CSR Building Products Limited v United States Gypsum Company

[2024] APO 1

IP AUSTRALIA

AUSTRALIAN PATENT OFFICE

CSR Building Products Limited v United States Gypsum Company [2024] APO 1

Patent Application:             2016284331

Title:Composite gypsum board and methods related thereto

Patent Applicant:                United States Gypsum Company

Opponent:CSR Building Products Limited

Delegate:M. Umehara

Decision Date:  23 January 2024

Hearing Date:  27 October 2023, by video conference

Catchwords:  PATENTS – Section 59 – opposition to grant of a patent – grounds of sufficiency, support, novelty and inventive step – technical contribution to the art does not extend to a general principle – the specification does not provide clear guidance telling the person skilled in the art how to adjust the process and materials so as to achieve with certitude the full range of products – citations do not disclose all features of the claims – it would not be a matter of routine to arrive at the claimed invention – opposition succeeds on section 40(2)(a) and section 40(3) – costs awarded

Representation:                   Counsel for the applicant: Gus Hazel and George Jackson

Patent attorney for the applicant: Andrew Scott and Sam Fraser of James & Wells
Counsel for the opponent: David Larish and Sophie Yates
Patent attorney for the opponent: Derek Baigent, Robert Wulff and John Scicluna of Griffith Hack

IP AUSTRALIA

AUSTRALIAN PATENT OFFICE

Patent Application:             2016284331

Title:Composite gypsum board and methods related thereto

Patent Applicant:                United States Gypsum Company

Date of Decision:                23 January 2024

DECISION

The opposition succeeds on the grounds of section 40(2)(a) and section 40(3) with respect to all claims, and fails on the grounds of novelty and inventive step.

I allow the applicant two (2) months from the date of this decision to file amendments to overcome the deficiencies identified in this decision.

I award costs according to Schedule 8 against the applicant, United States Gypsum Company.

REASONS FOR DECISION

Background

1. Australian patent application no. 2016284331 (the application) was filed under the provisions of the Patent Cooperation Treaty on 22 June 2016 and claims priority from US provisional patent applications 62/184060 filed 14 June 2015 and 62/290361 filed on 2 February 2016 as well as US utility model applications 15/186176, 15/186212, 15/18615/186232 and 15/186257 filed on 17 June 2016.  The application was filed by United States Gypsum Company (the applicant).

2. The application was accepted on 10 September 2021 with the notice of acceptance advertised on 30 September 2021.  While nothing turns on this point, divisional applications claiming priority from the opposed application have been filed.  AU 2021229169 was accepted on 2 September 2023 and a notice of opposition has subsequently been filed on 2 January 2024.  AU 2021229170 and AU 2021229171 are currently under examination.

3. On 20 December 2021, a notice of opposition under section 59 of the Patents Act 1990 (the Act) to the grant of a patent on the above application was filed by CSR Building Products Limited (the opponent).  A statement of grounds and particulars (SGP) was filed by the opponent on 21 March 2022.  The opponent then filed the evidence in support (EIS) on 21 June 2022.  The EIS consisted of a statutory declaration dated 20 June 2022 by Steven Sucech (Sucech #1) with supporting exhibits SS-1 to SS-16.

4. The applicant filed their evidence in answer (EIA) on 22 September 2022.  The EIA was comprised of a statutory declaration dated 20 September 2022 by Christopher Killalea (Killalea #1) with supporting exhibits CK-1 to CK-8 and a statutory declaration by William White (White #1) dated 21 September 2022 with supporting exhibits WW-1 to WW-8.   

5. The evidence in reply (EIR) was then filed by the opponent on 25 November 2022.  The EIR consisted of a second statutory declaration by Steven Sucech dated 22 November 2022 (Sucech #2) with supporting exhibits SS2-1 to SS2-5.

6. After filing the EIR, on 6 December 2022, the opponent requested to amend their SGP.  In the absence of any comments from the applicant on the matter, the SGP amendment was allowed on 23 December 2022.

7. Also on 23 December 2022, the applicant formally challenged the EIR as not being properly in reply.  Following a series of correspondences, on 15 February 2023, I directed that paragraphs [15], [16], [24]-[26], [28], [34], [36], [51], [57], [67], [77]-[79], [85], [87], [90]-[93], [110], [131], [135], [138], [147], [149], [150], [156], [161]-[163], [165], [166], [179] and [184] and exhibits SS2-2 and SS2-3 of Sucech #2 were not properly in reply to the EIA.  On 3 March 2023, I directed that these passages and exhibits will be consulted under Regulation 5.23.  Consequently, the entirety of Sucech #2 has been considered in this decision.

8. Responding evidence to the parts of Sucech #2 incorporated into evidence under Regulation 5.23 was filed by the applicant on 3 May 2023.  The responding evidence comprised of a statutory declaration dated 30 April 2023 by William White (White #2) with supporting exhibits WW-9 to WW-11 and a statutory declaration dated 2 May 2023 by Christopher Killalea (Killalea #2) with supporting exhibits CK-9 to CK-10.

9. On 19 May 2023, the applicant filed amendments under section 104 to the claims.  The amendment was allowed on 6 September 2023 without opposition.  Further references relate to the specification as amended.

10. On 13 October 2023, the opponent filed their summary of submissions.  The applicant filed their summary of written submissions on 20 October 2023.  The matter was heard by video conference on 27 October 2023.

    The nature of the opposition

11. In the SGP, the opponent listed the following grounds of opposition:

    -Section 59(a) – Entitlement

    -Section 18(1)(a) – Not a manner of manufacture

    -Section 18(1)(b)(i) – Lack of novelty

    -Section 18(1)(b)(ii) – Lack of inventive step

    -Section 18(1)(c) – Lack of utility

    -Section 40(2) – Not clear enough and complete enough

    -Section 40(3) – Lack of clarity and lack of support

12. At the hearing, the opponent did not press the grounds of entitlement, manner of manufacture, utility, or clarity. 

    Onus and standard of proof

13. The present case is governed by the Act as amended by the Intellectual Property Laws Amendment (Raising the Bar) Act 2012 (the Raising the Bar Act).  The standard of proof that applies in the present case is the balance of probabilities.  Under subsection 60(3A), if I am satisfied, on the balance of probabilities, that a ground of opposition to the grant of a patent exists, I may refuse the application.  Nevertheless, it remains the case that, in proceedings such as these before the Commissioner, the onus rests with the opponent to establish its case. 

    The specification

14. The specification includes 72 pages of written description, followed by 22 claims and 6 drawings.  Before construing the specification, I note the comments of Middleton J in Eli Lilly and Company Limited v Apotex Pty Ltd [2013] FCA 214 (Eli Lilly) at [139]:

    “It is well settled that the Court should, from the outset, approach the task of patent construction with a generous measure of common sense. The Court must place itself in the position of a person skilled in the relevant art, being the subject matter of the patent. From this perspective, the patent is to be read as a whole, in the context of the specification and in light of the prevailing common general knowledge and state of the relevant art at the priority date.”

15. The description begins by providing background information on gypsum boards and their manufacture.  A typical gypsum board is described at [0002] as being in the form of a set gypsum core sandwiched between two cover sheets with an optional densified at the paper-core interface and commonly used in drywall construction in interior walls and ceilings of buildings. 

16. The general manufacturing process for a typical gypsum board is described at [0003]:

    “During manufacture of the board, stucco (i.e., calcined gypsum in the form of calcium sulfate hemihydrate and/or calcium sulfate anhydrite), water, and other ingredients as appropriate are mixed, typically in a pin mixer as the term is used in the art. A slurry is formed and discharged from the mixer onto a moving conveyor carrying a cover sheet with one of the skim coats (if present) already applied (often upstream of the mixer). The slurry is spread over the paper (with skim coat optionally included on the paper). Another cover sheet, with or without skim coat, is applied onto the slurry to form the sandwich structure of desired thickness with the aid of e.g., a forming plate or the like. The mixture is cast and allowed to harden to form set (i.e., rehydrated) gypsum by reaction of the calcined gypsum with water to forma matrix of crystalline hydrated gypsum (i.e., calcium sulfate dihydrate).  It is the desired hydration of the calcined gypsum that enables the formation of the interlocking matrix of set gypsum crystals, thereby imparting strength to the gypsum structure in the product. Heat is required (e.g., in a ki1n) to drive off the remaining free (i.e., unreacted) water to yield a dry product.”

17. In the following passages at [0004] and [0005], some challenges in the art are described.  For example, the process of driving off the excess water is a point of inefficiency in the system but simply reducing the use of water can compromise the final product.  Another challenge in the art is reducing the weight of the gypsum board while maintaining its strength. 

18. At [0007]-[0014], a summary of the invention is provided.  Briefly, the composite gypsum board of the invention comprises a board core formed from at least water and stucco and a concentrated layer formed from an enhancing additive, water, and stucco.  Specifically incorporating higher concentrations of the enhancing additive in the concentrated layer, relative to the board core, contributes to “considerable advantage” described at [0027], including reducing overall enhancing additive use, reducing the overall cost of raw materials, enhancing efficiencies in manufacturing, and enhancing the product strength. 

19. At [0021], the nature of the invention is set out as the provision of a novel construction for a composite gypsum board and a method for making such a board.  The composite gypsum board is intended to have multiple layers containing different cementitious compositions.  One layer forms the board core, and another layer forms a concentrated layer, described as being “of substantial thickness (e.g., at least about 0.02 inches, or about 0.05cm).” 

20. The board core is described in detail at [0040]-[0064].  The board core forms the majority of the volume of the gypsum board and is formed from at least water and stucco.  The board core may include additional ingredients, such as low-density fillers, foaming agents, accelerators, retarders, dispersants, and phosphate-containing compounds.  At [0055], it is stated that an enhancing additive for imparting strength properties can also optionally be included in the slurry for forming the board core.

21. The concentrated layer is described in detail at [0065]-[0084].  The “concentrated layer” is referred to as such because of the presence of an enhancing additive in higher concentration than in the board core.  The concentrated layer is formed from a slurry comprising water, cementitious material, and an enhancing additive.  Upon drying, the concentrated layer has a density that is at least about 1.1 times higher than the density of the board core and a “substantial” thickness in the composite gypsum board product.  Incorporating fibre additives into the concentrated layer slurry imparts additional improvements to the process of preparing the gypsum board.  However, the addition of fibres is optional.

22. The enhancing additive is described at [00100]-[0118].  It provides desired strength properties, such as any one of compressive strength, nail pull resistance, flexural strength, core hardness or “other strength parameter”.  Examples of suitable enhancing additives that help provide strength are given at [00101]: starch, polyvinyl alcohol, boric acid, gypsum-cement, nano-cellulose and micro-cellulose.  With respect to starch, suitable examples are given as being hydroxylated starches, uncooked starches, pregelatinized starches (also referred to as “cooked starches”), high molecular weight acid-modified starches and functionalised starches.  These examples of starches are said to be preferred over low molecular weight acid-modified starches “which generally provide paper-core bond enhancement but not core strength enhancement.”  If a starch is used as the enhancing additive, it is present in the concentrated layer in an amount from about 5% to about 40% by weight of the stucco.

23. With respect to polyvinyl alcohol and/or boric acid, it is described at [0115]-[0116] that the strength of the facing paper is enhanced by their presence.  It is suggested that boric acid “acts as a cross-linker for the polyvinyl alcohol and starch to further enhance starch.”  The polyvinyl alcohol can be present in the concentrated layer in an amount from about 1% to about 5% by weight of the stucco.  The boric acid can be present in the concentrated layer in an amount from about 0.1% to about 1% by weight of the stucco.

24. With respect to nano-cellulose and micro-cellulose, it is suggested at [0117] that it may enhance nail pull resistance or “other strength parameter” when included in the concentrated layer at about 0.01% to about 2% by weight of the stucco.  Similarly, at [0118], gypsum-cement, included at about 5% to about 30% by weight of the stucco, is said to enhance nail pull resistance or “other strength parameter”.

25. Discussions of cover sheets at [0085]-[0099] and board strength at [0119]-[0124] are also provided.  It is clear that these are standard in the art, being described as being in any suitable form or meeting standardised measurement requirements.

26. The process of preparing the composite gypsum board of the present invention is described in detail at [0134]-[0136]:

    “Board is formed in a sandwich structure, normally concurrently and continuously, as will be understood in the art. The face cover sheet travels as a continuous ribbon on a conveyor. After being discharged from its mixer, the concentrated layer slurry is applied to the moving face cover sheet. Also, hard edges, as known in the art, can be formed, e.g., from the same slurry stream forming the concentrated layer for convenience, if desired.

    The board core slurry is then applied over the moving face paper bearing the concentrated layer slurry, and covered with a second cover sheet (typically the "back" cover sheet) to forma wet assembly in the form of a sandwich structure that is a board precursor to the final product. The back (bottom) cover sheet may optionally bear a skim coat, which can be formed from the same or different gypsum slurry as for the concentrated layer. The cover sheets may be formed from paper, fibrous mat or other type of material (e.g., foil, plastic, glass mat, non-woven material such as blend of cellulosic and inorganic filler, etc.). In some embodiments, the concentrated layer is applied on both major sides of the board, i.e., in bonding relation to both the top and bottom sheets.

    The wet assembly thereby provided is conveyed to a forming station where the product is sized to a desired thickness (e.g., via forming plate), and to one or more knife sections where it is cut to a desired length. The wet assembly is allowed to harden to form the interlocking crystalline matrix of set gypsum, and excess water is removed using a drying process (e.g., by transporting the assembly through a kiln), Surprisingly and unexpectedly, it has been found that board prepared according to the disclosure requires significantly less time in a drying process because of the low water demand characteristic of the board arrangement and composition. This is advantageous because it reduce energy costs.”

27. Following the discussion of the components of the invention, Examples 1-3 provided at [0139]-[0161] describe laboratory-based tests comparing various enhancing additives and concentration layer thicknesses and effects on board strength characteristics.  Example 1 compared a gypsum board sample absent a concentrated layer with samples having a concentrated layer comprising pregelatinized starch as the enhancing additive.  In example 2, discs made with various starches were compared as representative concentrated layers.  Example 3 demonstrates the optional use of fibres in the concentrated layer which also included pregelatinized starch as the enhancing additive and each slurry was then used to form a concentrated layer in separate production boards.  Examples 4-10 given at [0162]-[0185] provide worked examples of composite gypsum boards prepared on a production line.  These boards were prepared with pregelatinized starch as the enhancing additive.

28. Example 4 compares a typical gypsum board of the same thickness and weight to a composite gypsum board to confirm that nail pull resistance can be increased by including a concentrated layer.  Examples 5 and 6 then go on to tailor the ratios of ingredients to resist washout from the main slurry being poured onto the concentrated layer during the manufacturing process.  Examples 7 and 8 show that the density and the starch content of the concentrated layer can be used to improve nail pull resistance.  Example 9 shows improvement in nail pull resistance by increasing the thickness of the concentrated layer.  Example 10 compares two boards prepared to the same weight where one comprises a 0.5 inch core and the other comprises a 0.5 inch core and a 0.035 inch concentrated layer.  In these production line examples a main mixer was used to prepare the core slurry and a portion of this slurry was diverted for the concentrated slurry to a secondary mixer or a discharge conduit, where additional ingredients were added.

    The claims

29. The specification as amended includes a total of 22 claims with claim 1 being the only independent claim, which reads as follows:

    1. A composite gypsum board comprising:

    a)a board core comprising set gypsum formed from at least water, stucco, and optionally, an enhancing additive, the core having a dry density and dry thickness, the core defining first and second core faces in opposing relation; and

    b)a concentrated layer formed from at least water, stucco, and the enhancing additive, the concentrated layer disposed in bonding relation to the first core face, the concentrated layer having a dry density of at least about 1.1 times higher than the dry density of the board core; wherein:

    i.when the enhancing additive is present in forming the core, the enhancing additive is included in a higher concentration in forming the concentrated layer than in forming the board core, and

    ii.the board core dry thickness is greater than the dry thickness of the concentrated layer, the latter thickness being from 0.05cm to 0.23cm; and

    iii.the board has a nail pull resistance according to ASTM C473-10, Method B of at least 30.8 kg or 302.48 N.

30. Appended claims 2-22 define additional features relating to the arrangement of the various parts of the gypsum board, densities of the various parts, the nature and amounts of additives, and the like.

    Person skilled in the art

31. The specification is to be construed through the eyes of the person skilled in the art, a notionally non-inventive skilled worker aware of the common general knowledge in the relevant field.  In KD Kanopy Australasia Pty Ltd v Insta Image Pty Ltd [2007] FCA 481 at [16] Kiefel J identified the person skilled in the art as:

    “...a person acquainted with the surrounding circumstances of the state of the art and manufacture at the relevant time...They are likely to have a practical interest in the subject matter of the invention...and may often work in the art with which the invention is connected.”

1. In Root Quality Pty Ltd v Root Control Technologies Pty Ltd [2000] FCA 980, Finkelstein J stated at [70]:

   “He is the person to whom the patent is addressed and who must construe it.  He is the person whose knowledge will determine whether a patent is novel.  He is the person who will judge whether a patent is obvious.”

2. Finkelstein J went on to say at [70]-[72] that the hypothetical skilled person works in the field with which the invention is connected and is a non-inventive person or team likely to have a practical interest in the subject matter of the invention. 

3. As noted by Yates J in Otsuka Pharmaceutical Co., Ltd v Generic Health Pty Ltd (No 4) [2015] FCA 634 at [125]-[128], it is not permissible to treat the person skilled in the art as constituted by different teams depending on the patent question involved.  However, Nicholas J noted in ToolGen Incorporated v Fisher (No 2) [2023] FCA 794 (ToolGen) at [81] that the notional team for considering obviousness may have wider skills than the team required for sufficiency.

4. The key declarants in this matter are Mr Killalea and Mr White for the applicant and Mr Sucech for the opponent.  All three declarants hold positions within businesses that are engaged in the production and supply of gypsum boards, including composite gypsum boards.  Furthermore, all three declarants have worked with the applicant in some capacity in their careers.

5. Mr Killalea is an industrial engineer and project manager for a licensee of the applicant. Mr Killalea has been involved in the manufacturing process of gypsum boards in various capacities such as process control, engineering, equipment design, equipment selection, installation, procedures and commissioning and project management. This is detailed in Killalea #1 at [5].

6. Mr White has had a half-century career with the applicant’s parent company and has held the position of the Vice President of Advanced Technology since 2009. His current duties include technology acquisition and licensing activities. However, he has also had experience in the management of plants, technical services and research and development in building materials. This is detailed in White #1 at [2].

7. At the hearing, the opponent raised concerns as to the impartiality of the evidence given by Mr White, given his long career with the applicant’s parent company.  I accept that the identity of the expert witness and their independence may be a relevant consideration when assessing the weight that can be given to their evidence, but these are not the only considerations in that assessment.  Other considerations may include the nature and relevance of their experience and evidence, and as discussed above, whether the evidence is provided from the point of view of the person skilled in the particular art.  Taking these broader considerations into account, I do not consider the issues identified by the opponent justifies the exclusion of evidence from Mr White, even though it may necessitate a detailed consideration as to the weight it can be given in the circumstances. 

8. Mr Sucech is a technical consultant providing technical assistance and guidance in operations of gypsum board manufacturing as well as developing new gypsum formulations and additives.  A significant portion of his experience includes his employment with the applicant, during which time he developed and implemented new products, formulation additives and processes.  This is detailed in Sucech #1 at [8]-[11].

9. While a technical consultant, vice president in charge of technology acquisition and industrial engineer would have different levels of knowledge and interests in the field, a range of persons could provide useful evidence.  In this case, I will have regard to the evidence of all declarants.  Where there is conflict in their evidence, I will resolve that conflict in the usual manner. 

10. On the face of the specification, there is little doubt that the notional person skilled in the art includes a person with experience in making gypsum boards, and in particular composite gypsum boards.  Such persons would have knowledge of the various ingredients and processes used in manufacturing these boards.  It is clear that the person skilled in the art would also need to possess an understanding of the effect of altering the ingredients or making modifications to the manufacturing processes on the final product and properties required for the product type. 

11. All three experts agreed that laboratory technicians and plant engineers would be part of the team constituting the notional person skilled in the art.  Mr Sucech, at [104] of Sucech #1, included suppliers of the materials in the team of persons skilled in the art.  However, Mr Killalea, at [64] of Killalea #1, stated that suppliers were only involved to the extent that they supplied what was specified.  Similarly, Mr White, at [58] of White #1, noted that suppliers would be included “only if they were part of a particular targeted mission.”  Consequently, I consider that suppliers may be a resource that the laboratory technicians and engineers may consult, rather than active members of the team.

12. Mr Killalea further included the following additional team members in Killalea #1 at [64]:

    -A quality manager for ensuring that the specified product is being made on the line;

    -Operators for actually making it;

    -A production manager for deciding which product to make and when to make it; and

13. Similar to the suppliers, I consider that quality managers, machine operators and production managers are people who are involved in making gypsum boards.  However, these additional roles would not necessarily possess an understanding of the effect of altering the ingredients or making modifications to the manufacturing processes on the final product and properties required for the product type.  I do not consider the additional roles to contribute to developing a new gypsum board product.

14. Consequently, I consider the person skilled in the art to include laboratory technicians and plant engineers who, respectively, formulate slurry compositions and set up the production equipment to make gypsum boards.  While these are the critical members of the team of persons skilled in the art, in the present case, nothing turns on the inclusion or exclusion of the other additional members who are involved in the production aspects. 

    Common general knowledge

15. Common general knowledge is the background knowledge and experience available to all those working in the relevant art.  Aickin J stated in Minnesota Mining and Manufacturing Co v Beiersdorf (Aust) Ltd [1980] HCA 9 (Minnesota Mining) at [115]:

    “The notion of common general knowledge itself involves the use of that which is known or used by those in the relevant trade.  It forms the background knowledge and experience which is available to all in the trade in considering the making of new products, or the making of improvements in old, and it must be treated as being used by an individual as a general body of knowledge.”

16. However, it is not enough that information is recorded in a document, even if that document is widely circulated.  Middleton J explained in Ranbaxy Laboratories Limited v AstraZeneca AB [2013] FCA 368 at [217], that it is only part of the common general knowledge when it is generally known and accepted in the art:

    “…information does not constitute common general knowledge merely because it might be found, for example, in a journal, even if widely read by persons in the art … Reference in this regard is made to the words of Luxmoore J in British Acoustic Films (1936) 53 RPC 221 at 250, cited by Lehane J in Aktiebolaget Hässle v Alphapharm Pty Ltd (1999) 44 IPR 593; [1999] FCA 628 at 605 [39]:

    In my judgment it is not sufficient to prove common general knowledge that a particular disclosure is made in an article, or series of articles, in a scientific journal, no matter how wide the circulation of that journal may be, in the absence of any evidence that the disclosure is accepted generally by those who are engaged in the art to which the disclosure relates. A piece of particular knowledge as disclosed in a scientific paper does not become common general knowledge merely because it is widely read, and still less because it is widely circulated. Such a piece of knowledge only becomes general knowledge when it is generally known and accepted without question by the bulk of those who are engaged in the particular art; in other words, when it becomes part of their common stock of knowledge relating to the art.”

17. Much of the evidence on common general knowledge was agreed to by both parties.  The evidence establishes that the relevant common general knowledge at the priority date included:

    (a)General knowledge of how to formulate and produce gypsum boards, including the fundamentals and what generic ingredients would be used;

    (b)Relevant standards to which commercial gypsum boards must comply (including the nail pull test);

    (c)Manufacturing systems and analysis techniques for gypsum boards;

    (d)The use of skim coats (including methods and equipment for thickness control) in gypsum boards; and

    (e)General use of additives, such as foaming agents, dispersants, fluidisers, fillers and the like.

18. These are consistent with the background information provided in the specification. I emphasise that a typical gypsum board, in the most basic form, consists of a single core layer and a cover sheet on each face. The core layer, in the most basic form, is made by pouring a slurry of water and calcined gypsum, also known as stucco. Additives may be used to adjust the properties of the slurry and/or to alter the properties of the gypsum board. For example, Mr Sucech noted that the present application used several additives in the slurries, including heat resistant accelerator, foaming agent, retarder, dispersant, alum, glass fibre, and dextrose, and noted “I consider these to be typical additives.” in Sucech #1 at [221].

19. Mr Killalea and Mr White, respectively in Killalea #1 at [69] and White #1 at [63], both qualified that while the person skilled in the art would have general knowledge of formulating and producing gypsum boards, specific formulations used by different companies would be trade secrets.  This is because each additive may have a knock-on effect, requiring other additives to counteract any undesirable effect.  As can be seen from the list of additives noted by Mr Sucech above, there is an accelerator and a retarder, which impart opposing effects but are balanced to give the desired pouring, setting and product properties.  This highlights that every new formulation is developed empirically, balancing the target product properties with processing requirements.  

20. In the context of the present invention, Mr Sucech gave examples of strength enhancing additives, such as pregelatinized starch and sodium trimetaphosphate (STMP) in Sucech #1 at [26] and [27], respectively. While Mr Killalea suggests in Killalea #1 at [343] that STMP is not a common additive, it was nevertheless known in the art. Mr Killalea also offers boric acid as an alternative agent to stiffen the board and reduce sag in Killalea #1 at [321]. Mr White agreed with Mr Sucech, in White #1 at [21], that polymers can also improve the strength of a gypsum board.

21. Put another way, typical gypsum boards are generally known in the art and there are many additives which are also generally known in the art.  The key to success lies in how you use the additives, which is why the experts consider different companies’ formulations as trade secrets. 

22. Arguably of less relevance to the present invention itself but of significant relevance to the matter at hand is the skim coat, which received much attention from the experts and the parties.  The skim coat is also known as a densified layer, hardfacing layer or bonding layer and these terms are used interchangeably throughout the evidence given by the experts.  There appears to be no technical difference between these terms and the choice of language does not raise any confusion or concerns of technical error for the experts.  To assist readability, I have adopted the term ‘skim coat’ for referring to this layer in the context of the invention, as it is the term used in the specification.

23. As noted above, gypsum boards typically have a cover sheet, which may be applied directly onto the core layer or a skim coat may be used as a bonding layer between the cover sheet and the core.  Mr Sucech gave a description of a typical skim coat in Sucech #1at [39]:

    “I would say typical [skim coats] were around 1/16 in thick (~0.159cm) before the Priority Date, and still are today. Typical [skim coats] have a density 25-35% higher than that of the core for example.”

24. Mr Sucech also described the history of the skim coat in Sucech #1 at [29]:

    “[Skim coat] technology has existed for around 25+ years, with many major plasterboard manufacturers using some type of [skim coat] since long before the Priority Date. Originally, skim coats of slurry with low or no foam were applied to facing paper, followed by the less dense or foamed core slurry. The original purpose was to improve paper-to-core bonding, and the aim has been to make [skim coats] as thin as possible, while achieving sufficient paper/core bond.”

25. Mr Killalea described the process of adding skim coat in Killalea #1 at [25]:

    “I will clarify that the [skim coat], where used, was produced using the same slurry as the core slurry, with the only possible difference being the amount of foam or water incorporated. In general terms, the slurry mixer will have a primary outlet (for the core) and a secondary outlet of smaller capacity for the [skim coat]. The primary outlet may have (more) foam added in that outlet stream so as to create a core of reduced density.”

26. From the evidence of all three experts, it was not common general knowledge to introduce additives specifically to the skim coat slurry, which was not already in the core slurry. In particular, Mr Sucech indicated that it was not common general knowledge to add strengthening additives to skim coat for the purposes of increasing nail pull resistance of a gypsum board in Sucech #1 at [48]. Mr Killalea and Mr White also shared similar experiences as that of Mr Sucech in regard to their experiments with adding strengthening additives to skim coats to no avail in Killalea #1 at [48] and White #1 at [38], respectively.

    Construction

27. The correct approach to the construction of claims was discussed by Bennett J in H Lundbeck A/S v Alphapharm Pty Ltd [2009] FCAFC 70; 81 IPR 228 at [118]-[120]:

    “the words in a claim should be read through the eyes of the skilled addressee in the context in which they appear...while the claims define the monopoly claimed in the words of the patentee's choosing, the specification should be read as a whole ... it is not permissible to read into a claim an additional integer or limitation to vary or qualify the claim by reference to the body of the specification...terms in the claim which are unclear may be defined or clarified by reference to the body of the specification.”

    Composite gypsum board

28. Claim 1 is the only independent claim and defines a composite gypsum board comprising a board core and concentrated layer, having a nail pull resistance according to ASTM C473-10, Method B, of at least 30.8kg or 302.48 N.  None of the experts questioned the use of the term ‘composite gypsum board’.  The opponent characterised the term, at [63] of their submissions, as a whole gypsum board made up of several parts.  The specification at [0021] refers to an aspect of the invention as “the composite board contains multiple layers which contain different cementitious compositions”.

29. The composite gypsum board as claimed is made up of a core layer and a concentrated layer which contain different compositions.  Claim 1 further defines that the concentrated layer is “disposed in bonding relation to the first core face” and has a density of at least about 1.1 times higher than the dry density of the board core.  In order for the two layers to be described in this manner, they must be distinct layers as opposed to relative zones in a single continuum throughout the thickness of the board. 

30. The composite gypsum board is distinguished from a typical gypsum board in being made up of multiple core layers which contain different compositions.  As I have discussed above, all three experts gave evidence that a typical gypsum board was prepared from a core slurry and, when present, the same core slurry would be used for the skim coat as well.  While they were not put to the task of distinguishing the two types of gypsum boards, from the common general knowledge on typical gypsum boards, it is clear that having multiple core layers distinguishes the claimed composite gypsum board. Simply put, a typical gypsum board would only have a single core layer and the use of a skim coat is not generally regarded as making a composite gypsum board.  

31. In the context of the present application, it is clear that the claimed invention relates to a composite gypsum board having multiple distinct layers forming the core, the composite board as a whole exhibiting the claimed minimum nail pull strength. 

    Board core

32. There was no apparent dispute between the experts as to what was intended by the board core as defined in the claims.  However, as the board core plays an important role in the present invention, I will discuss its features.

33. The board core comprises set gypsum formed from at least water, stucco, and optionally an enhancing additive.  The board core has two opposing faces and its dry thickness is greater than the dry thickness of the concentrated layer.

34. Typical gypsum board cores generally comprise set gypsum formed from drying a slurry of at least water and stucco poured out in sheet form.  Mr Sucech described the process of making conventional gypsum boards in Sucech #1 at [19]:

    “In the most basic form, gypsum board generally consists of a gypsum core that is faced with two covering sheets. These sheets are typically paper or fibreglass. The core is formed by first producing a slurry of calcined gypsum (also known as stucco) with water and typically a range of additives including starches, fluidisers and surfactant foams. The ingredients are added to a mixer (pin-type or pin-less-type) and mixed to produce the slurry for gypsum board manufacture.”

35. Consequently, with the exception of its occurrence as part of a composite gypsum board, the board core of the present claims appears to be an ordinary board core found in the art. 

    Concentrated layer

36. At the hearing, the opponent highlighted that none of the experts were familiar with the term “concentrated layer”.  The opponent characterised the use of the term as jargon introduced by the applicant.  Throughout the evidence, submissions and at the hearing, the nature of the “concentrated layer” was discussed at length. 

37. Claim 1 defines the concentrated layer as being formed from at least water, stucco, and an enhancing additive and it is disposed in bonding relation to the first core face.  The enhancing additive is included in a higher concentration in forming the concentrated layer than in forming the board core.  Hence the name, “concentrated layer”.  In its dry form, the concentrated layer has thickness in the range of 0.05 cm to 0.23 cm and a density of at least about 1.1 times higher than the dry density of the board core.

38. Mr Sucech stated that “The patent uses the term "concentrated layer(s)" but this is simply another name for a [skim coat].” at Sucech #1 [111]. I note that Mr Sucech was asked to provide general comments in relation to gypsum boards prior to being shown the present application. The first questions asked of Mr Sucech, listed at [17] of Sucech #1, was for him to provide comments on [skim coat] technology and additives used in gypsum boards at the relevant time, in particular:

    ·The state of skim coat technology leading up to the priority date;

    ·How skim coats were applied;

    ·How skim coat thickness was controlled during production and measured in finished boards;

    ·The use of any additives in board cores or skim coat and relative amounts of those additives in the skim coat and the core;

    ·The purpose of starch addition to gypsum boards and the different types of starches used in gypsum board making at that time.

1. Mr Sucech’s statements at Sucech #1 [19]-[90] answer these points.  It is therefore not surprising that, when Mr Sucech was provided with the present application, he considered the concentrated layer to be interchangeable with skim coats commonly used in the art.  Mr Sucech’s evidence on the concentrated layer was given after the idea of skim coats had been imprinted.  Following criticisms from Mr Killalea and Mr White on this point, Mr Sucech explained in his second declaration, in Sucech #2 at [41], as follows:

   “… I note that claim 1 of the 331 Application also requires that the concentrated layer has "a dry density of at least about 1.1 times higher than the dry density of the board core". I understand that the claims of the 331 Application set out the scope of the invention. Because of this density requirement, the claimed invention requires that the concentrated layer be more-dense than the core of the board. This is why I consider the 'concentrated layer' claimed and exemplified by the 331 Application to be similar to conventional [skim coats]. I do understand that not all [skim coats] can be considered to be 'concentrated layers', unless they have a higher concentration of an enhancing additive.”

2. At the hearing, the opponent accepted that not all skim coats would be concentrated layers as defined in the present application. 

3. To my mind, if the concentrated layer was equivalent to a typical skim coat, the claimed product would be a typical gypsum board.  However, the present invention is directed to a composite gypsum board requiring multiple distinct layers making up the body of the board.  I also note that the specification discusses the addition of skim coats to the composite gypsum board of the invention at [0135] of the specification and the skim coat is added to the composite gypsum board in claim 18.  It is therefore clear that “concentrated layer” was not intended to encompass a skim coat as known in the art.  

4. As discussed above, it was common general knowledge that a typical skim coat is 25-35 % denser than the core layer and has a thickness of around 0.159 cm.  These features are shared by the concentrated layer of the claims.  However, a concentrated layer must also have a higher concentration of an enhancing additive.  In this regard, it was common general knowledge that skim coats are prepared from the same slurry composition as the core.  Furthermore, the addition of a skim coat to a typical gypsum board core only makes a typical gypsum board.  It would be absurd to include typical gypsum boards within the scope of composite gypsum boards. 

5. Consequently, I agree with the criticisms from Mr Killalea and Mr White that it would be wrong to equate the concentrated layer with a typical skim coat.  The concentrated layer is a distinct layer in the body of the composite gypsum board.  The concentrated layer must be formed from at least water, stucco and enhancing additive, have a higher concentration of the enhancing additive than the core, a dry density of at least 1.1 times higher than the dry density of the core layer, and a thickness of 0.05cm to 0.23cm.  

   Enhancing additives

6. At the hearing, there was agreement between the parties that the specification defines enhancing additives as a “strength-imparting additive” which provides “desired strength properties”.  This is consistent with the evidence provided by the experts. 

7. All of the experts referred to the specification rather than pointing to any technical meaning in the art.  The specification at [00100] provides suitable enhancing additives which help provide strength, listing “starch, polyvinyl alcohol, boric acid, gypsum-cement, nano-cellulose, micro-cellulose, or any combination thereof.”  At [00101], examples of the strength characteristics of the board to be enhanced by the additive is given as compressive strength, nail pull resistance, flexural strength, core hardness, or other strength parameter.   

8. At [107] of the opponent’s submissions, the term is characterised as being “very broad”.  Although the applicant disputed that the term was unduly broad, the applicant submissions at [91]-[94] concludes that the evidence points to the term as meaning “an ingredient, or combination of ingredients, that can be added to a layer to increase strength of the board relative to what the strength of the board would be without it.”

9. Breadth of the term being a separate consideration, I understand “enhancing additives” to include within its scope any additive that contributes to providing increased strength to the final product in some way.  While examples of suitable additives are given in the specification, the term is not limited to these examples.  

   Clear enough and complete enough disclosure

10. The opponent’s submissions on clear enough and complete enough disclosure and support overlap considerably.  I have dealt with the issues raised as I see most appropriate to each ground. 

11. Subsection 40(2)(a) requires that the complete specification must disclose the invention in a manner which is clear enough and complete enough for the invention to be performed by a person skilled in the relevant art.  In CSR Building Products Ltd v United States Gypsum Company [2015] APO 72 (CSR 2015) at [95], the delegate formulated the following three steps:

    1 – Construe the claims to determine the scope of the invention as claimed;
    2 – Construe the description to determine what it discloses to the person skilled in the art; and
    3 – Decide whether the specification provides an enabling disclosure of all the things that fall within the scope of the claims.

12. In Evolva SA [2017] APO 57, the third question was reformulated as the following two-step consideration:

    1 – Is it plausible that the invention can be worked across the full scope of the invention?
    2 – Can the invention be performed across the full scope of the claims without undue experimentation?

13. This approach has found approval with the Federal Court in Cytec Industries Inc v Nalco Company [2021] FCA 970 at [143]-[146] and Jusand Nominees Pty Ltd v Rattlejack Innovations Pty Ltd [2022] FCA 540 at [373]-[379], which has further been confirmed on appeal by the Full Court in Jusand Nominees Pty Ltd v Rattlejack Innovations Pty Ltd [2023] FCAFC 178. Also, recently in ToolGen, at [167]-[175], Nicholas J further analysed the Explanatory Memorandum to the Intellectual Property Laws Amendment (Raising the Bar) Bill 2011 and the alignment of Australian law with that of UK and European laws of sufficiency.

14. An invention may be defined in general terms and be considered enabled, provided that the specification discloses a principle of general application.  This is explained in Biogen v Medeva plc [1996] UKHL 18; [1997] RPC 1 at [48]-[49]:

    “If the invention discloses a principle capable of general application, the claims may be in correspondingly general terms. The patentee need not show that he has proved its application in every individual instance. On the other hand, if the claims include a number of discrete methods or products, the patentee must enable the invention to be performed in respect of each of them.

    Thus, if the patentee has hit upon a new product which has a beneficial effect but cannot demonstrate that there is a common principle by which that effect will be shared by other products of the same class, he will be entitled to a patent for that product but not for the class, even though some may subsequently turn out to have the same beneficial effect... On the other hand, if he has disclosed a beneficial property which is common to the class, he will be entitled to a patent for all products of that class (assuming them to be new) even though he has not himself made more than one or two of them.”

1. The gist of the opponent’s argument was that, with the exception of the production line examples, the specification does not provide sufficient information to enable a person skilled in the art to produce a composite gypsum board having all of the claimed properties.  It is their view that while the specification provides general discussion of enhancing additives, methods of making composite gypsum boards and methods of testing various physical properties of composite gypsum boards and parts thereof, the invention cannot be performed across the full breadth of the invention without undue experimentation and there is a lack of guidance in the specification on how to proceed in case of failure.

2. The applicant submitted that, in addition to a series of production line examples of Examples 4-10, the information given in the body of the specification and the laboratory-based tests of Examples 1-3 provided sufficient information to enable the person skilled in the art to work the invention across the full breadth of the invention.  The applicant pointed to the evidence given by Mr White and Mr Killalea, who opined that they could replicate the invention described in the specification.  The applicant further submitted that “a routine method of formulation trialling is not 'undue experimentation'.”

3. In contrast, Mr Sucech explained in Sucech #1 at [124]:

   “… changing a parameter such as the type of enhancing additive or even the amount of enhancing additive used, is not necessarily straightforward. This is because so many aspects of the board core/concentrated layer composition interact – e.g. the type of additive, the amount of water required, whether a dispersant is needed, etc. As the composition changes, the conditions required to produce the slurry, set and dry the board etc. also change. It would take considerable trial and error for the skilled person to successfully substitute pregelatinized starch with each of the different potential enhancing additives noted in the Patent (such as other starches, polyvinyl alcohol, boric acid, gypsum-cement, nano-cellulose, and/or micro-cellulose) and/or change the amount of enhancing additives in a board so as to achieve a lightweight board with the required strength properties, according to the Patent.”

4. At the hearing, the opponent presented five specific points of concern.  I will discuss these in turn. 

   No enhancing additive in core

5. The opponent submitted that all production line examples included an enhancing additive, in particular pregelatinized starch, in the core of the composite gypsum board as well as in the concentrated layer.  In contrast to this, the claims include embodiments where the enhancing agent was not present in the core.  The applicant agrees, specifically stating at [280](a) of their submissions that: “It is optional.” 

6. At the hearing, the applicant further pointed me to parts of the specification where the addition of enhancing additive to the core slurry was not mandatory.  For example, the addition of an enhancing additive to the core slurry is optional at [0055] and may be included at about 0% by weight of stucco at [0114] and [0116]-[0118].  It was stressed that 0% of an ingredient pointed to its absence in that slurry.

7. The nail pull resistance required in the claims is at least 30.8 kg.  Mr Sucech noted in Sucech #1 at [131] that this nail pull resistance is “lower than what is required by the ASTM C1396 "Standard Specification for Gypsum Board" of 77 lbs force”, which would be equivalent to 34.9 kg.  Given that the composite gypsum board of the present application is not required to meet the commercial standard for strength, I do not consider that there would be undue burden for a person skilled in the art to prepare a composite gypsum board as claimed having no enhancing additive in the core. 

   Not only pregelatinized starch / Acid modified starch

8. These points in the opponent’s submissions revolve around the breadth of the term “enhancing additive”.  The construction of the term was previously discussed.  Both parties and all experts agreed that an enhancing additive was an additive that contributes to providing increased strength to the final product in some way. 

9. At [00100] of the specification, six classes of enhancing additives are identified.  They are starch, polyvinyl alcohol, boric acid, gypsum-cement, nano-cellulose, micro-cellulose, or any combination thereof.  Starch includes subclasses of cooked (pregelatinized), uncooked, acid modified, otherwise chemically modified or natural starches. 

10. At the hearing, I raised the question of the sheer breadth of the term “enhancing additive” with the applicant.  Their response was that the breadth of enhancing additives encompasses agents that provide desired strength properties because “enhancing additives” was itself a principle of general application.  They went on to say that the six classes of agents have been particularly identified as enhancing additives and whether or not something beyond those named additives might amount to an enhancing additive in the context of this application is something that the person skilled in the art can explore and determine, for example by the methodology given in Example 2.

11. The applicant drew an analogy to CSR Building Products Limited v United States Gypsum Company [2017] APO 64 (CSR 2017), where the delegate had considered the burden placed upon a person skilled in the art to carry out bench top tests to enable a broader range:

    “I also find it plausible, based on the information provided in the specification, that the skilled addressee has at their disposal all the information required to enable them to adjust the amounts of the key ingredients of gypsum and high expansion vermiculite in alternative preparations of gypsum panel and utilise these relatively inexpensive bench top tests to verify their performance parameters as correlated to commercially available Type X panels, in order to arrive at a gypsum panel which is fire resistant, without undue burden.”

12. I note that the consideration of high expansion vermiculite as a class is significantly narrower than enhancing additives.  Furthermore, in CSR 2017, the performance parameters were tested against a single commercial product for a single purpose.  This is contrasted with the present application where any number of physical properties relating to strength in some way could be the subject of testing.  While I appreciate that bench-testing is a common aspect of the development process, the scale of work left for the person skilled in the art in the present application is incomparable to CSR 2017. 

13. Simply relying on broad terms to capture embodiments which have not been properly enabled does not represent a principle of general application and does not justify a person skilled in the art extending the scope of the claims beyond their contribution to the art.  The applicant’s invitation for the person skilled in the art to determine further suitable alternatives by conducting their own research highlights the lack of a general principle across the full breadth of the term “enhancing additive” in the present application. 

14. The opponent conceded that there was sufficient information provided in the specification, particularly through the production line examples 4-10, to enable a person skilled in the art to work the invention where the enhancing additive was pregelatinized starch. 

15. I consider that the specification, at best, provides a starting point for further research to be conducted by a person skilled in the art.  However, changing the enhancing agent from pregelatinized starch is not a simple matter of substituting like for like.  Mr Sucech stressed the impact of changing the enhancing additive in the slurries in Sucech #1 at [116]:

    “Changing the compositions provided in the examples, to replace pregelatinized starch with one of the other claimed enhancing additives (different starches, polyvinyl alcohol, boric acid, gypsum-cement, nano-cellulose, and/or micro-cellulose), may necessitate a complete reformulation of the slurry composition and changes to the processing parameters for the boards. This is because different additives can have different effects on slurry fluidity, water demand, drying conditions, setting time etc.”

16. In this regard, specific information for each of starch, polyvinyl alcohol, boric acid, gypsum-cement, nano-cellulose and micro-cellulose is given at [0114]-[0118] of the specification.  While no particular mechanism for imparting strength to a gypsum board is suggested for gypsum-cement, nano-cellulose or micro-cellulose, at [0115] it is suggested that polyvinyl alcohol and boric acid “positively impact strength in the face paper” and that boric acid further acts as a cross-linker for the polyvinyl alcohol and starch to further enhance starch.  In contrast, at [0151] of the specification, the enhancing property of starch is attributed to “extra bonding between gypsum crystals”.  Otherwise, according to the specification at [00101], an enhancing agent may provide any of compressive strength, nail pull resistance, flexural strength, core hardness or “other strength parameter”. 

17. In addition to the varied mechanisms of strengthening properties, each class is suggested for incorporation at very different concentrations.  For instance, starch of any type may be present in the concentrated layer in an amount from about 5% to 40% by weight of the stucco.  This is contrasted to 1-5% for polyvinyl alcohol, 0.1-1% for boric acid, 0.01-2% for nanocellulose or microcellulose and 5-30% for gypsum cement.

18. In contrast to the extensive discussion of starches as enhancing agent throughout the specification, discussion of polyvinyl alcohol, boric acid, gypsum-cement, nano-cellulose, micro-cellulose is limited to [0115]-[0118].  Given the different mechanisms by which the enhancing agents may provide strength to the composite gypsum board and the considerable alterations to the slurry formulation that would be required for each class, any detailed guidance given with respect to pregelatinized starch would be rendered useless to a person skilled in the art with respect to any other enhancing agent.   

19. On balance I consider it would require an undue burden to work the invention substantially across its full scope in relation to the enhancing additive.  The specification therefore does not disclose the invention in a manner that is clear enough and complete enough for the invention to be performed by a person skilled in the relevant art in relation to the definition of enhancing additive.  On the other hand, I consider the specific choice of pregelatinized starch as the enhancing additive is sufficiently enabled by the specification. 

    No separate slurries

20. With respect to the requirement for separate slurries, the opponent and the applicant are again in agreement.  The opponent submissions at [141]-[148] explain that the claims do “not necessarily require that the composite gypsum board have been formed by a separate core and concentrated layer slurries.”  The opponent submissions at [142] explains that a board could be formed from a single slurry poured as a whole or identical slurries poured separately, where the migration of an ingredient during the drying process would increase its concentration at the surface, thereby forming the concentrated layer and a core layer by a relative accumulation of additives towards the surface of the board upon drying. 

21. The applicant submissions at [280] agree that “[t]he use of multiple slurries is not claimed, what is claimed is a product with a concentrated layer not a method of making that.”  Within the same paragraph, they go on to say that “It is not necessary for there to be multiple slurries, but it is clearly an option.”  The applicant drew my attention to the specification at [0129], which provides that the slurry for the concentrated layer may be a portion of the same slurry as that used to prepare the board core, which is diverted to a separate discharge port and the enhancing additive is added in the line.  Alternatively, two mixers can be connected in series or two separate mixers can be used to prepare slurries for each of the core and concentrated layers. 

22. In any event, given my construction for the body of the composite gypsum boards requiring a distinct core layer and a distinct concentrated layer, rather than relative zones in a single continuum, nothing turns on this point. 

    Concentrated layer thickness

1. Opponent’s final point of concern with the themes of enablement lay in the examples having been worked over a range of concentrated layer thicknesses from 0.0635 cm to 0.1016 cm whereas the concentrated layer in claim 1 is defined in the range 0.05 cm to 0.23 cm. 

2. The opponent submissions at [149]-[152] note that the upper bound of 0.23cm is “extremely thick”, being more than twice the thickest concentrated layer in the examples. While Mr Sucech did note that “a thickness of 0.23 cm for the concentrated layer is extremely thick” at [129] of Sucech #1, he also stated that “I will refer to 'concentrated layers' interchangeably as 'densified layers', 'concentrated layers' and/or 'hardfacing layers'…” in Sucech #1 at [100]. I note that densified layers and hardfacing layers are used interchangeably in the art for ‘skim coat’, which is the term I have used. As explained with regard to the common general knowledge, a typical skim coat has a thickness of around 0.159 cm. Consequently, it is not surprising that Mr Sucech characterised the upper bound the concentrated layer being 0.23 cm as being “extremely thick” for a skim coat.

3. The applicant submissions at [280](e) states that “A range of thicknesses is a principle of general application, accordingly the Application does not have to prove the application of the claims in every individual instance of a suitable thickness within that range.”  However, as discussed above, a broad term is not itself a principle of general application.  A range of thickness, in and of itself, is not a principle of general application. 

4. Despite this, I consider that concentrated layers having a range of thicknesses can be prepared by the person skilled in the art without undue burden.  Although the worked examples are limited to a range of concentrated layer thicknesses from 0.0635 cm to 0.1016 cm, the opponent has provided no evidence to establish that a person skilled in the art cannot produce a composite gypsum board with a concentrated layer ranging from 0.05 cm to 0.23 cm and that such a board will have the required nail pull resistance.  Mr Sucech merely noted that the upper bound was extremely thick, not that such a layer could not be made. 

   Conclusion on clear enough and complete enough disclosure

5. The composite gypsum board of the invention must have a concentrated layer with a higher density in relation to the board core layer and a required thickness, and the composite gypsum board as a whole must have the required nail pull resistance.  It is not a simple matter of whether a person skilled in the art can mix a slurry with a certain number of ingredients, choosing an ingredient as an enhancing additive, whether slurries are poured separately for the concentrated layer and the core layer or how thick the concentrated layer is.  The important question is whether there is sufficient information provided in the specification to enable a person skilled in the art to make a composite gypsum board having the required properties with certitude. 

6. There are many variables that will affect the final properties of a composite gypsum board.  The specification does not provide clear guidance for the person skilled in the art how to adjust the process and materials as to achieve with certitude the full combination of properties, in particular the nail pull resistance, of the composite gypsum board when the enhancing additive is not pregelatinized starch. 

7. The production line examples provide critical information in relation to the slurry formulations that enable the invention to be worked where the enhancing additive is pregelatinized starch.  The ingredients and their respective ratios in the slurry formulations given for the core layer and the concentrated layer are important information to enable a person skilled in the art to make the claimed composite gypsum boards.  While a person skilled in the art may experiment for optimum conditions, pour rate, line speed, drying temperature and the like are all key information for the person skilled in the art to prepare any gypsum board successfully.  As a consequence of the variables involved, the specification fails to provide sufficient information to enable a person skilled in the art to work with any other enhancing additive and production method. 

8. I am satisfied that the specification does not provide a disclosure of the claimed invention that is clear enough and complete enough for the invention to be performed by a person skilled in the art. 

   Support

9. Both parties made similar comments on support to those made under the grounds of clear enough and complete enough disclosure.  I see no need to reiterate these in full again. 

10. Subsection 40(3) as amended by the Raising the Bar Act requires that the claims must be supported by matter disclosed in the specification.  Burley J explained in Merck Sharp & Dohme Corporation v Wyeth LLC (No 3) [2020] FCA 1477 at [546]-[547]:

    “In CSR Building Products Ltd v United States Gypsum Company [2015] APO 72, Dr S D Barker adopted the summary provided by Aldous J in Schering Biotech at 252 – 253, which has been often followed in the United Kingdom (emphasis added):

    …to decide whether the claims are supported by the description it is necessary to ascertain what is the invention which is specified in the claims and then compare that with the invention which has been described in the specification. Thereafter the court’s task is to decide whether the invention in the claims is supported by the description. I do not believe that the mere mention in the specification of features appearing in the claim will necessarily be a sufficient support. The word "support" means more than that and requires the description to be the base which can fairly entitle the patentee to a monopoly of the width claimed.

    That approach encapsulates broadly the claim support obligation under s 40(3). To it may be added the requirement that the technical contribution to the art must be ascertained. Where it is a product, it is that which must be supported in the sense that the technical contribution to the art disclosed by the specification must justify the breath of the monopoly claimed.”

11. In Cytec Industries Inc. v Nalco Company [2021] FCA 970 at [120], Burley J made a similar observation. Similarly, Nicholas J, most recently in ToolGen at [391]-[395], considered the ground of support and affirmed the approach taken by Burley J. In that decision, Nicholas J also stressed the following at [396]:

    “The question whether a disclosure in a patent application fairly entitles the patentee to a monopoly of the width claimed calls for an assessment of the patentee’s contribution to the art, which must be weighed against the scope of the patentee’s monopoly as defined by the claims.  The monopoly, according to UK and European authorities, must be justified by the technical contribution to the art that arises from the disclosure of the specification.”

12. The approach to determining whether the requirements of support are satisfied as approved by the Federal Court was set out in CSR 2015 at [115]:

    i.construe the claims to determine the scope of the invention as claimed,

    ii.construe the description to determine the technical contribution to the art, and

    iii.decide whether the claims are supported by the technical contribution to the art.

13. This guidance is particularly relevant to the present case.  At the hearing, the opponent submitted that the specification mentioned options for including or not including enhancing additives in the core layer, a range of six possible enhancing additives, and a range of thicknesses for the concentrated layer.  However, the opponent went on to say that support requires more than a “mere mention” of features. 

14. In Jusand Nominees Pty Ltd v Rattlejack Innovations Pty Ltd [2022] FCA 540, Rofe J had regard to the principles set out by the UK Supreme Court decision in Regeneron Pharmaceuticals Inc v Kymab Ltd [2020] UKSC 27, which stated that in the case of a product claim, the contribution to the art is the ability of the skilled person to make the product itself, rather than (if different) the invention. Rofe J continued at [503]-[504]:

    “…In the case of a product, the contribution to the art is the product which is enabled to be made by the disclosure. Sufficiency requires substantially the whole range of products within the scope of the claim to be enabled to be made by means of the disclosure in the patent, and this both reflects and applies the principle that the contribution to the art is to be measured by the products which can thereby be made as at the priority date, not by the contribution which the invention may make to the value and utility of the products, the ability to make which, if at all, lies in the future.

    Enablement across the scope of a product claim is not established merely by showing that all products within the relevant range will, if and when they can be made, no matter how much ingenuity is required, deliver the same general benefit intended to be generated by the invention.”

15. As noted by Rofe J, a key consideration in the case of a product is what the specification enabled to be made at the priority date.  This was confirmed by the Full Court in Jusand Nominees Pty Ltd v Rattlejack Innovations Pty Ltd [2023] FCAFC 178 (Jusand) at [222]-[224]. 

16. At [159] of the opponent’s submissions, the technical contribution of the present application is summarised as follows: 

    “a)a composite gypsum board with a nail pull resistance according to ASTM C473-10, Method B of at least 30.8 kg or 302.48 N, comprising:

    (i)a board core comprising [pregelatinized] starch;

    (ii)a concentrated layer comprising [pregelatinized] starch, the concentrated layer:

    A.    having a dry density of at least about 1.1x higher than the dry density of the board core;

    B.     having a dry thickness less than the dry thickness of the board care; and

    C.     having a dry thickness of 0.06 to 0.105 cm;

    b)  the composite gypsum board having been formed using a concentrated layer slurry and a board core slurry, the former of which had a higher concentration of [pregelatinized] starch than the latter.”

17. According to the opponent, the claims lack support because they extend beyond this technical contribution.  Applicant submissions at [296] gladly acknowledged this concession that “there is a technical contribution to the art” (emphasis in original) and “that something in claim 1 is supported.”  However, I note that it is the full breadth of the claims that must be supported, not just something falling within their scope.

18. The applicant submitted that the specification does not have to prove the workability of every possible embodiment falling within the scope of the claims through the provision of worked examples.  However, I do not understand the opponent to be suggesting that the only way to enable an embodiment is through worked examples.  I do not consider that there is any requirement for a patentee/applicant to demonstrate every embodiment within the scope of the claims have been tried, tested, and proven to have been enabled to be made in the specification.  However, it is a risk taken by said patentee/applicant that the scope of what has been enabled may be challenged, as is the case here.   

19. At the hearing, the opponent confirmed that it is not their submission that specific exemplification of all combinations of features is the only way to achieve enablement across the full breadth of the claims.  Nevertheless, it is their view that the present specification does not enable a person skilled in the art to prepare composite gypsum boards having the claimed properties beyond the embodiments shown in Examples 4-10 and the contribution to the art cannot be extended to other composite gypsum boards. 

    No enhancing additive in core

20. As indicated above, there is no undue burden in preparing a board core without an enhancing additive.  That is, if required, a person skilled in the art would be able to make a composite gypsum board having  no pregelatinized starch in the core and still having the required nail pull resistance without the need for further invention.  Furthermore, Mr Killalea and Mr White opined that the specification provides a workable standard that would allow a person skilled in the art to prepare a composite gypsum board having a board core and a concentrated layer, with a nail pull resistance of at least 30.8 kg, as explained in Killalea #1 at [210] and White #1 at [121]-[122], respectively. 

21. Mr Sucech observed in Sucech #1 at [121] that all of the core slurries in the production line examples contained “an extremely high quantity of pregelatinized starch in the core”.  Mr Sucech explained that, in his experience, 2-8 lbs/1000 square feet (MSF) would be a high content of pregelatinized starch, while some of the boards in Examples 4-10 contain up to 20 lbs/MSF of pregelatinized starch in the core.  Mr Sucech reiterated at [215] of Sucech #1 that “pregelatinized starch is a well-known strength enhancing additive” , and that “in the amounts used in every Example of the Patent, would certainly contribute positively to the nail pull results obtained.”

22. I have no doubt that high quantities of an ingredient known to enhance the strength of a gypsum board would contribute to the overall strength of the composite gypsum boards in the examples of the present application.  However, the use of strengthening additives to the core was already common general knowledge in the art.  Consequently, overdosing the core with a well-known strengthening additive is not a technical contribution to the art.  Furthermore, as noted by Mr Sucech himself, the required nail pull resistance of the claimed gypsum boards is lower than the industry standard.  Consequently, it would be plausible for a person skilled in the art to expect that a composite gypsum board without enhancing additives in the core would meet the requirements of the claims.

    Not only pregelatinized starch / Acid modified starch

23. At the hearing, the opponent submitted that the passages at [0114]-[0118] of the specification referring to the six enhancing additives were not sufficient to enable a person skilled in the art to put them all to practice without undue burden.  The applicant submitted that enhancing additive was itself a principle of general application.

24. I am unable to find any principle that would allow a person skilled in the art to apply generally across a range of ingredients representing the full breadth of enhancing agents.  Admittedly, the specification at [0009] states that:

    “Surprisingly and unexpectedly, the concentrated layer, formed from a higher weight percentage of the enhancing additive, is able to distribute the desired resulting properties throughout the board core, such that the board exhibits the strength properties.  As a result, the board core can be made with less overall enhancing additive, and in some embodiments can be lighter and less dense than conventional board cores.  In turn, overall board weight can be reduced as the density in a large weight section of the board (i.e., the core) is reduced.”

25. This would suggest that having the layered structure in the composite board is the principle of general application allowing a person skilled in the art to make stronger, lighter boards with less ingredients. However, according to Mr Sucech, at [30] of Sucech #1, “Manufacturers have tried in the past making the [skim coat]s thicker, to improve nail pull resistance of the boards, but this has not worked well.” Similarly, Mr Killalea recalled his past efforts experimenting with “thicker and thinner [skim coat]s in the 2000s to see if those changes would affect nail pull resistance.” in Killalea #1 at [33]. For completeness, Mr White, in White #1 at [27], also agreed that the skim coat does not really affect nail pull resistance and that “there would only be a marginal improvement in nail pull by using a thicker [skim coat].”

26. Consequently, it is not just the layered structure in the composite gypsum board or the thickness of the concentrated layer that provides the required nail pull resistance.  The higher concentration of the enhancing agent in the concentrated layer distinguishes the present composite gypsum board from typical gypsum boards and is key in achieving the required nail pull resistance.  This effect has been shown with pregelatinized starch and Examples 4-10 provide sufficient guidance for a person skilled in the art to prepare a composite gypsum board with the required nail pull resistance.  

27. The applicant’s contribution to the art resides in producing a composite gypsum board with a concentrated layer enhanced by pregelatinized starch.  Although the specification names other candidates for the enhancing agent, given the varied mechanisms for imparting strength and suggested quantities for each of the alternatives, the specification does not enable the full breadth of the enhancing agents in the composite gypsum board.

    No separate slurries

28. As indicated above, given my construction for the composite gypsum boards requiring a distinct core layer and a distinct concentrated layer, rather than relative zones in a single continuum, nothing turns on this point.   

29. Mr Killalea stated in Killalea #1 at [27] that Mr Killalea himself had never seen a production line where two or more mixers were used to create different slurries for use in the same board before the priority date. However, Mr Killalea was otherwise quite familiar with separately pouring a skim coat and a core layer in Killalea #1 at [25]. The technical contribution does not reside in the idea of separately pouring layers of a composite gypsum board.

    Concentrated layer thickness

30. As indicated above, I consider the concentrated layer in claim 1 having a thickness of 0.05 cm to 0.23 cm to be enabled across its full breadth.  Production line examples 4-10 have been worked over a range of concentrated layer thicknesses from 0.0635 cm to 0.1016 cm. 

31. According to Mr Killalea in Killalea #1 at [39], adjusting the amount of slurry exiting the outlet of the mixer is a common way of controlling the thickness of a layer.  Mr Sucech offers additional strategies in Sucech #1 at [36], such as controlling the shape of the discharge port of the mixer, changing discharge hose length, or controlling the speed of the roller moving the cover paper onto which the slurry is being poured.  Although these examples were given with respect to skim coats, the same principles for pouring slurries would apply to other layers as well.

32. On balance, I do not consider that the broader range of concentrated layer thickness to exceed the applicant’s contribution to the art.

    Conclusion on support

33. I agree with the opponent that, despite the specification providing some additional information on the alternative enhancing agents at [0115]-[0118], the claimed invention exceeds the technical contribution the specification makes to the art.  As noted in CSR 2015 at [110], an important consideration when considering support is whether the technical contribution is a general principle or the specific examples in the specification.

34. The contribution to the art made by the present application resides in the use of pregelatinized starch in the concentrated layer, which forms part of the body of a composite gypsum board.  While the pregelatinized starch may have been added for the purposes of enhancing the concentrated layer, a broad term such as an enhancing agent does not constitute a principle of general application.  In the absence of a principle of general application, the specific use of pregelatinized starch in the composite gypsum boards is the applicant’s contribution to the art.

    Novelty

35. It is a requirement of subsection 18(1) of the Act that the invention, so far as claimed in any claim, is novel. Downes J recently summarised the requirements for novelty in Allied Pumps Pty Ltd v LAA Industries Pty Ltd [2023] FCA 1457 at [187] as follows:

    “The starting point for determining novelty is s 7(1) of the Patents Act, which provides that an invention is taken to be novel when compared with the prior art base unless it is not novel in light of prior art information made publicly available in: a single document or through doing a single act; or in two or more related documents, or through doing two or more related acts, if the relationship between the documents or acts is such that a skilled addressee would treat them as a single source of information.”

1. It is well established that the general test for lack of novelty is the reverse infringement test, as set out by Aickin J in Meyers Taylor Pty Ltd v Vicarr Industries Ltd [1977] HCA 19 at [20]:

   “The basic test for anticipation or want of novelty is the same as that for infringement and generally one can properly ask oneself whether the alleged anticipation would, if the patent were valid, constitute an infringement.”

2. It follows that if a citation discloses all the integers of the claim, the claim will lack novelty.  If the citation does not disclose all the integers of the claim, the claim will still lack novelty provided the citation discloses all the essential integers of the claim.  However, if one or more of the essential integers are not disclosed in the citation, the claim is novel (see Nicaro and Catnic Components Ltd v Hill and Smith (1982) RPC 183).

3. It is noted that General Tire & Rubber Company v The Firestone Tyre and Rubber Company Limited [1972] RPC 457 at [486] stated that:

   “If … the prior publication contains a direction which is capable of being carried out in a manner which would infringe the patentee’s claim, but would be at least as likely to be carried out in a way which would not do so, the patentee’s claim will not have been anticipated, although it may fail on the ground of obviousness.”

   and that, in order to meet the test for anticipation, the prior art:

   “…must contain clear and unmistakeable directions to do what the patentee claims to have invented…A signpost, however clear, upon the road to the patentee’s invention will not suffice. The prior inventor must be clearly shown to have planted his flag at the precise destination before the patentee.”

4. More recently, Beach J in BlueScope Steel Limited v Dongkuk Steel Mill Co., Ltd (No 2) [2019] FCA 2117 stated at [1025]:

   “It is not sufficient to demonstrate that a prior publication is capable of being carried out in a manner which would equally infringe or not infringe the particular claim.  In such a case there would not be the relevant anticipation.  To elaborate, if the prior art is a document and there is ambiguity in the sense that the disclosure can be read in two or more ways, such that one way would, if carried out, infringe, and one or more other ways would not, then there has been no anticipation.  Anticipation must not merely be a possibility or even a likely consequence of performing the invention disclosed by the prior art, but it must necessarily be entailed in or an inevitable result of carrying out the disclosure.”

5. However, Beach J went on to say at [1026]:

   “An invention can be patentable even if it was only conceived in the mind (it can be "remembered from a dream" (Wellcome Foundation Ltd v VR Laboratories (Aust) Pty Ltd (1981) 148 CLR 262 at 286)), if it otherwise satisfies the requirements of the Act. Likewise, a publication can anticipate even if it is purely theoretical. In Merck & Co Inc v Arrow Pharmaceuticals Ltd (2006) 154 FCR 31, the Full Court upheld the primary judge's decision that Lunar News anticipated the claims of a patent to a method of treatment despite the fact that the article said that the proposed new dosing regimen needed to be tested (at [104]). The Court rejected the notion that the need for routine testing and experimentation meant that a prior suggestion could not be novelty defeating (at [104] to [112]).”

6. At the hearing, the opponent advanced that claims 1-5, 7-9, 11, 16, 17, 19, 21 and 22 lack novelty in view of the disclosure of US 2012/0207989 A1 (D1) alone or in combination with US 2010/024937 A1 (D12) and US 5714032 B (D13), which are incorporated by reference into D1. 

   The nature of the submitted prior art

7. Mr White provided a convenient summary of the disclosure of D1 in White #1 at [73]:

   “D1 describes making composite boards. The composite boards have multiple core layers that increase overall nail pull resistance because of their different densities, and the greater thickness of the first, denser core layer. The densities are controlled by controlling foam in the layers. The first core layer is a layer that is made denser by taking foam out. To improve nail pull, this first core layer has an exaggerated thickness, which seems to have been designed only under lab bench conditions.”

8. At [0043] of D1, the addition of “an accelerator, retarder, an enhancing agent, a strength additive, or any combination thereof” to any core layer cementitious composition is disclosed.  In D1, examples of “enhancing agents” are given at [0045], such as phosphonic or phosphonate-containing ingredients, while “strength additives” are given at [0053] and includes starches, such as corn, wheat, potato, or tapioca starches, and may also be pregelatinized starches.  [0053] of D1 reads on as follows:   

   “Enhancing nail pull resistance can be achieved in a multi-layer core board by having two or more core layers such that the facing core layer has a higher concentration of strength additives than a non-facing core layer. Although the density of the facing core layer may not be different than the non-facing layer(s), the presence of the strength additives can allow for the multi-layered board to have improved nail pull resistance compared to a board with a single layer, the multi layered board and single layer board having the same facing material and the same overall thickness, and the single layer board comprised of a layer of the non-facing layer of the multi-layered board and having the same overall amount of strength additives as the non-facing layer. In addition, it is contemplated that embodiments of the invention can be substantially free of strength additives as described herein. As used herein, "substantially free" means that the composition of the present invention contains 0 wt.% based on the weight of stucco of additive, or no additive, or an ineffective trace amount of additive.”

9. Alternative additives disclosed in D1 include hydroxyethylated starch at [0054]; polyvinyl acetate polymer, monobasic phosphate, and boric acid at [0056]; and structural additives such as mineral wool, perlite, clay, vermiculite, calcium carbonate, polyester, paper fibre, foaming agents, fillers, sugars, borates, binders, colourants, fungicides, and the like at [0057].

10. A general manufacturing process for the multi-layered boards is given at [0058] of D1 as follows:

    “[A]pplying on the facing material a first cementitious composition having a first density, to form a first core layer; allowing the first core layer to at least partially set; and applying on the first core layer a second cementitious composition having a second density, to form a second core layer. The first density is higher than the second density, and the partial setting of the first layer conforms to the level of setting as described in ASTM C472 at 10.3.1 or until the first layer is sufficiently set so that wash-out of the first layer is substantially prevented when the second layer is applied.”

11. At [0061] of D1, reference is made to D12:

    “A skim coat is a very thin, very dense layer of a cementitious composition that assists in bonding the facer material to the core layer, as discussed above, the slurry of which also may form the edges of the board, as is described in U.S. Patent Application Publication No. 2010/0247937, which is incorporated by reference herein in its entirety.”

12. At [0070] of D1, reference is made to D13:

    “In one aspect, the additives may be introduced in multiple mixer arrangements known in the art. See, e.g., U.S. Pat. No. 5,714,032 and U.S. Pat. Appl. Pub. No. 2004/0134585 A1, each incorporated by reference herein in its entirety.”

13. In the examples spanning [0077]-[0094] of D1, gypsum boards with multiple core layers were prepared in a laboratory setting, each core comprising at least stucco, water, pregelatinized corn starch and foaming agents, which are compared against single-layer gypsum boards made from the same slurry composition.  For preparing boards with multiple core layers, the non-facing core layer was poured on top of the facing core layer about 10 minutes after the facing core layer was poured, when the facing core layer was already set hard. 

    Consideration of novelty

14. At the hearing, the opponent submitted that the disclosure of D1 was “very similar to” the present application.  The facing core layer having a higher density than the non-facing core layer and the multiple layers forming a composite gypsum board.  Although not exemplified, the opponent submitted that the facing core layer, if and when incorporating a strength additive, would resemble the concentrated layer of the present application and the non-facing core layer would be representative of the core layer of the present application.  

15. In contrast, the applicant submitted that a concentrated layer was not disclosed in D1.  The applicant submissions at [135] state that other kinds of layers are disclosed while the concentrated layer of the present application is new and quite different because it contains an enhancing additive.  In response, the opponent stressed that [0053] of D1 taught that the nail pull resistance could be enhanced by having two or more core layers such that the facing core layer has a higher concentration of strength additives than a non-facing core layer. 

16. I agree with the opponent insofar as the facing core layer of D1 being comparable to the concentrated layer as defined in the present application if and when it is formulated to have a higher concentration of strength additives and a higher density than the non-facing core layer.  However, as noted by the applicant, D1 does not provide clear and unmistakable directions for making a composite gypsum board with a facing core layer having the required dry density with the required thickness range and including a strength additive, where such a board would also have a minimum nail pull resistance according to ASTM C473-10, Method B, of at least 30.8 kg.

17. The matter of whether D12 and D13 were incorporated by reference into D1 such that a person skilled in the art would treat them as a single source of information as prior art base for novelty was raised at the hearing.  I have not considered the matter any further as the disclosure of D1 itself does not provide specific, clear and unmistakable directions and adding further documents cannot increase the specificity of the disclosure.    

    Conclusion on novelty

18. I consider that the claims are novel in view of D1 (alone or incorporating D12 and D13) and the opponent has not made out the ground of novelty.

    Inventive step

19. Subsection 7(2) states that an invention is taken to involve an inventive step unless it would have been obvious to a person skilled in the art in light of the common general knowledge (whether in or out of the patent area) before the priority date of the relevant claim when considered alone or together with the information mentioned in subsection 7(3). 

1. Subsection 7(3) defines the relevant information as:

The information for the purposes of subsection (2) is:

(a)   any single piece of prior art information; or

(b) a combination of any two or more pieces of prior art information that the skilled person mentioned in subsection (2) could, before the priority date of the relevant claim, be reasonably expected to have combined.

1. Importantly, where a claim is directed to a combination of known integers, obviousness is not established merely by identifying each of those features in the prior art or the common general knowledge.  This was explained by Aickin J in Minnesota Mining at [116], stressing that the question is whether the combination of those features is obvious. In a similar vein, the High Court in Lockwood Security Products Pty Ltd v Doric Products Pty Ltd (No 2) [2007] HCA 21, at [111], said that the question of whether it would be obvious to add one integer to a combination of other integers:

“…will turn on what a person skilled in the relevant art, possessed with that person’s knowledge would have regarded, at the time, as technically possible in terms of mechanics, and also as practical. … Even if an idea of combining integers, which individually may be considered mere design choices, is simple, its simplicity does not necessarily make it obvious.”

Consideration of inventive step

1. Although other documents were presented to the experts and discussed in their evidence, at the hearing, the opponent only pressed D1, incorporating D12 and D13 by reference, and in combination with common general knowledge.  

2. The opponent submitted that obviousness falls to be assessed based on the practical and commercial reality of the priority date.  They went on to submit that D1 would be the starting point for the person skilled in the art, who would then adapt the teaching therein to the commercial and practical reality of gypsum board manufacturing rather than looking at D1 in a vacuum.  Accordingly, the opponent posed that the person skilled in the art, starting from D1, would choose slurry formulations, layer thicknesses, and production processes according to their production needs to arrive at an embodiment falling within the scope of the present claims.  However, the opponent did not provide what production needs would be driving the person skilled in the art in making these decisions.

3. The applicant submissions at [234]-[237] characterise the very long setting time between the pouring of the core layers in the examples of D1 as being completely impractical in a production line setting and that the person skilled in the art would consider the composite gypsum board of D1 to be a specialised product due to this difficulty.  The applicant submissions at [248]-[251] summarise the evidence of Mr White and Mr Killalea on D1 as merely motivating the person skilled in the art to produce thick, denser, core layers if a specialised board was needed with increased nail pull.  The applicant goes on to conclude at [252] of their submissions that “it would not have been obvious from D1 in combination with the common general knowledge to arrive at the invention the subject of the Application.”

4. On that note, Mr Killalea gave his consideration of D1 in Killalea #1 at [81]-[82]:

   “D1 describes the use of multi-layer boards - two of the layers being called "core layers" - shown as 41 and 32. The Figures make those layers look very thick - a lot thicker than the skim coats shown as 21 and 22. As I have explained in paragraphs [32] to [42] above, I was familiar with skim coats, which are otherwise known as hardfacing layers or densified layers. However I was not at all familiar with the layering of the core as suggested in D1 immediately before 24 June 2015.

   I am not sure exactly how you would apply this technology to the commercial manufacture of gypsum boards. Perhaps this could be done by using two rollers and applying different layers of slurry into the core between the two facing sheets.”

5. I find Mr Killalea’s statement difficult to reconcile with his statements regarding the sufficiency of information provided by the present application.  With regard to the concept of layering of the core layers in D1 as opposed to the concentrated layer and core layer in the composite gypsum board of the present application, prima facie, the level of disclosure regarding their manufacture appears similar.  Given the similarities, it is surprising that Mr Killalea considered the present specification to provide sufficient guidance in this regard but not D1.  In any case, it is clear that simply knowing the components and the desired structure of the product does not enable a person skilled in the art to prepare a composite gypsum board, even where basic preparatory instructions are provided.

6. While [0053] of D1 does provide information on strength additives, such as starches, the strength additives may be used in a higher concentration in the facing layer than in the non-facing layer (or not).  Moreover, the addition of strength additives to any part of the composite gypsum board is optional in D1.  I also note that the worked examples of D1 use the same slurry for both the facing and the non-facing core layers, wherein the amount and/or aeration time of foaming agents for the different core layers provides the different densities. 

7. With the benefit of hindsight, one can identify information in D1 for individual elements that could make up the composite gypsum board of the present application.  However, obviousness is not established merely by separately identifying each of the claimed features in the prior art, there must be some a priori motivation for a skilled person to proceed to a particular combination.  

8. At the hearing, the parties further exchanged submissions on additional features, such as the exaggerated thickness of the facing layer (in comparison to a typical skim coat), the impractical drying time required between the pouring of the two core layers, and whether the use of enhancing additives in a skim coat could improve nail pull resistance.  However, I note that the facing core layer in D1 and the concentrated layer in the present claims are not skim coats.  D1 discloses the application of a skim coat.  Consequently, submissions made in relation to a typical skim coat or possible modifications to a skim coat does not aid my consideration in the present matter.  

9. On balance, I consider that there is no motivation in D1 that would direct a person skilled in the art to include a strength additive in a higher concentration in the facing core layer relative to the non-facing core layer.  Furthermore, there is nothing in the common general knowledge or in D12 or D13 that would lead the person skilled in the art to the claimed invention.

   Conclusion on inventive step

10. The opponent has not established that the claims lack inventive step in light of D1 (with or without incorporating D12 and D13), alone or in combination with common general knowledge.

    Conclusion

11. The opposition succeeds on the grounds of section 40(2)(a) and section 40(3), and fails on all other grounds.

12. Despite my determination, I consider that the specification includes patentable subject matter and these issues can be overcome by amendment.  I therefore allow the applicant two (2) months from the date of this decision to propose amendments to overcome the issues identified.

    Costs

13. The normal approach is that costs should follow the event.  I see no sufficient reason to depart from this approach.  The opposition is successful.  Accordingly, I award costs in accordance with Schedule 8 against the applicant, United States Gypsum Company.

    M. Umehara

    Delegate of the Commissioner of Patents