Xylotheque Ltd v Construction Research & Technology GmbH
[2014] APO 1
•15 January 2014
IP AUSTRALIA
AUSTRALIAN PATENT OFFICE
Xylotheque Ltd v Construction Research & Technology GmbH [2014] APO 1
Patent Application: 2007272060
Title:Stable air-placed concrete accelerator dispersion with a high active substance content
Patent Applicant: Construction Research & Technology GmbH
Opponent: Xylotheque Ltd
Delegate: Karen Ayers
Decision Date: 15 January 2014
Hearing Date: 31 October 2013
Catchwords: PATENTS - opposition to the grant of the patent under s 59 – opposed on the basis of novelty and inventive step – opposition unsuccessful – accelerator storage stability in dispersions and solutions was a known problem but required different approaches – insufficient evidence to establish that a skilled worker would apply a successful approach in one system across to the second
Representation: Patent applicant: Craig Smith of counsel instructed by Carolyn Harris and Grant Jacobsen of Watermark- Melbourne
Opponent:Julian Cooke of counsel instructed by Frank Papamichalakis Pappas IP. The opponent’s European attorney (Robin Browne) also attended
IP AUSTRALIA
AUSTRALIAN PATENT OFFICE
Patent Application: 2007272060
Title:Stable air-placed concrete accelerator dispersion with a high active substance content
Patent Applicant: Construction Research & Technology GmbH
Date of Decision:
DECISION
The opposition is unsuccessful. Subject to appeal, I direct this application proceed to sealing. Costs awarded according to Schedule 8 against the opponent, Xylotheque Ltd.
REASONS FOR DECISION
Background
Patent application 2007272060 was filed in the name of Construction Research &Technology GmbH on 27 February 2007 under the provisions of the PCT. It claimed priority from an EP application (EP 06014696) which was filed on 14 July 2006.
The Australian application was published accepted on 21 January 2010 and on 21 April 2010, a notice of opposition was filed by Xylotheque Ltd. Evidence was completed in this matter on 23 October 2012 and the matter was set for hearing in Canberra on 31 October 2013.
Evidence
The following evidence was filed in this matter:
(a)Evidence in support
Statutory declaration by Roar Myrdal dated 20 December 2010 together with exhibits RM-1 to RM-3 (Myrdal-1)
Statutory Declaration by Frank Pappas dated 22 December 2010 together with exhibits FP-1 and FP-2 (Pappas)
(b)Evidence in Answer
Statutory declaration by Montserrat Alfonso dated 26 March 2012 together with exhibits MA-1 to MA-6 (Alfonso)
(c)Evidence in Reply
Statutory declaration by Roar Myrdal dated 8 October 2012 plus exhibits (RM-4 to RM-7) (Myrdal-2)
(d)Further Evidence (Applicant)
Statutory declaration by Elena Kolomiets dated 23 January 2013 plus exhibits (EK-1 to EK-3)
(e)Evidence in response to the further evidence (Opponent)
Statutory declaration by Roar Myrdal dated 20 March 2013 (Myrdal-3)
Statutory declaration by Roar Myrdal dated 14 October 2013 (Myrdal-4)
Onus of Proof
The request for examination in relation to this patent application was filed on 27 March 2009. As a consequence, substantive amendments of the Patents Act brought about by the Intellectual Property Laws Amendment (Raising the Bar) Act 2012 do not apply to the present application. This includes the amendment to subsection 60 (3A) that allows the Commissioner to refuse a patent application if satisfied on the balance of probabilities that a ground of opposition exists.
Consequently it appears that the former standard for opposition proceedings applies and the opponent must establish that it is clear or practically certain that the patent is invalid (F Hoffman La Roche AG v New England Biolabs Inc [2000] FCA 283 at [29], [67]; 50 IPR 305 at 311, 319; Commissioner of Patents v Sherman [2008] FCAFC 182 at [18], [22]; 79 IPR 426; Genetics Institute Inc v Kirin-Amgen Inc [1999] 92 FCR 106 at [17]).
Specification
The specification as accepted relates to an alkali free accelerator for air-placed concrete and pneumatically applied mortar. This type of concrete (known as “shot concrete” or “shotcrete”) is sprayed onto the face of rock excavation surfaces (such as tunnels or mines) to form a protective layer and stabilise the site. Accelerators ensure that the shotcrete when applied sets quickly and has good early strength. For full effectiveness, this strength also needs to be maintained over the long term (final strength).
The accelerators originally used were strongly alkaline and therefore unpleasant and dangerous to use. Hence by the priority date, these had effectively been replaced by alkali-free products. The alkali-free accelerators contained aluminium sulphate and/or aluminium hydroxide in either a solution or a dispersion. Both products were required to be storage stable (so that the product did not precipitate, crystallise or gel) and have a high active substance (aluminium) content.
The specification lists a number of disadvantages of the prior art alkali-free accelerators including:
(a) High costs with using large amounts of aluminium hydroxide (more than 10%);
(b) High costs using large amounts of carboxylic acids;
(c) Insufficient early strength using a combination of aluminium sulphate and diethanolamine; and/or
(d) Insufficient final strength when aluminium sulphate, aluminium hydroxide and a carboxylic acid is used.
The accelerator of the current invention is said to eliminate these disadvantages. It is stable and rapid setting providing both good early and final strength. The accelerator comprises an aqueous dispersion of aluminium sulphate (Al2(SO4)3), a further aluminium compound and an inorganic stabiliser magnesium silicate (particularly sepiolite). The specification uses aluminium hydroxide (Al(OH)3) as the additional source of aluminium.
10.The specification ends with 13 claims only one of which (claim 1) is independent. This claim defines:
Accelerator for air-placed concrete or pneumatically applied mortar which is present as an aqueous dispersion which contains the following:
(a)25 to 40% by weight of aluminium sulphate,
(b)At least one further aluminium compound so that the molar ratio of aluminium to sulphate in the dispersion is from 1.35 to 0.70; and
(c)An inorganic stabilizer which comprises a magnesium silicate.
Preliminary matters
11.Shortly before the hearing date, the opponent filed a request to amend the Statement of Grounds and Particulars to particularise a lack of novelty allegation in relation to D2[1]. This document was listed in the admitted prior art of the opposed specification[2] and had been previously identified as the closest prior art in relation to inventive step. I am therefore satisfied that the applicant would have been aware of this document and its relevance well before the hearing. The applicant provided submissions to address the novelty concerns at the hearing and I consider that natural justice has been applied. I therefore formally allowed the amendment to the SGP at the beginning of the hearing.
[1] D2: EP 0812812-A1 (MBT Holding AG) published 17 December 1997
[2] Opposed specification page 3, line 1
Common General Knowledge
12.A key issue in dispute in this opposition was the nature of the CGK in Australia. The applicant noted that shotcrete accelerator products were not produced in Australia at the priority date and that neither party was able to locate an Australian expert in these proceedings. They argued that there was therefore no relevant common general knowledge base in Australia for this particular industry[3].
[3] Applicant’s submissions at [29]-[30]
13.However these products had been widely sold and have been used in Australia for decades by multi-national companies in the construction and mining industries and the technology used in Australia was the same as that used in other countries[4]. The four largest international suppliers of alkali-free shotcrete (BASF Construction Chemicals (earlier MBT, Degussa), SIKA, Grace Construction Products and Mapei) are all multinational companies with a significant presence in Australia[5]. I agree that with the opponent that these products are part of a global industry which includes Australia.
[4] Opponent’s submissions at [29(h)]
[5] Myrdal-1 at [10]
14.The applicant argued this did not necessarily establish that the underlying chemistry was known. However in my view a skilled worker using the products in Australia would be well-appraised of the different commercial products and be interested in new developments in the field. The chemistry is not complicated and has been discussed at a number of international conferences both within and outside Australia. There were also books published on the subject[6]. This suggests that the art was widely known and understood in this country. There is therefore no reason why Australia would have a different level of CGK in this field compared to the rest of the world despite the products themselves not being produced in this country. I therefore reject the applicant’s argument that the CGK in Australia was different to the international CGK.
[6] Opponent’s submissions at [29(d)-(g)]
15.The parties also disagreed on some key aspects of the international CGK. I will discuss the main dispute later in my determination of inventive step. However in order to provide some context for the following novelty and inventive step discussions, it is worthwhile for me to outline the agreed aspects of CGK and to resolve some of the less critical disagreement upfront.
16.Both parties accepted that an important factor in the preparation of alkali-free accelerators is controlling the levels of aluminium. It was known that a shorter setting time could be achieved with higher percentages of aluminium[7] but it was also recognised that if the percentage of aluminium was too high, the stability (and the later compressive strength) of the admixture was affected[8].
[7] Myrdal-1 (EIS) at [19]
[8] Myrdal-2 at [3e]
17.At the priority date, all (or virtually all) alkali-free accelerators contained high levels of aluminium sulphate[9]. This salt is highly soluble in water (36g/100cm3 at 20oC)[10] and therefore provides high levels of dissolved aluminium. The salt also reacts with the calcium hydroxide in the cement to form a solid cementitious product (ettringite) and aluminium hydroxide[11]:
[9] Myrdal-1 at [18]
[10] Myrdal-1 at [19]
[11] Alfonso at [17]
Al2(SO4)3 + 6Ca(OH)2 + 32 H2O → 3CaO∙Al2O3∙3CaSO4∙32H2O (ettringite) + Al(OH)3
18.Not only is ettringite responsible for the rapid setting of the shotcrete, the by-product (Al(OH)3) itself is an accelerator which contributes to the rapid setting.
19.There were two known forms of alkali-free accelerators containing aluminium sulphate. The first form was a dispersion (or suspension) where the only source of aluminium is aluminium sulphate. Such suspensions would have a molar ratio of Al:SO4 of 0.67 (the ratio of aluminium to sulphate in Al(SO4)3). The second form was a solution containing both aluminium sulphate and aluminium hydroxide.
20.For both the dispersion and solution forms, the aim is to obtain a stable product with an aluminium sulphate concentration which is close to its limits of solubility. As Dr Myrdal noted:[12]
[12] Myyrdal-1 at [19]
“the skilled person was aware that one wanted the highest level of aluminium present as possible, but without going too much beyond the saturation level (as the resulting suspension will become unstable - that is liable to settling out or gelling - if high levels of undissolved particles are present). For these reasons it was common to dissolve aluminium sulphate in concentrations from just below saturation point (for solution formulations), to a bit above the saturation concentration of Al2(SO4)3 (for dispersions or suspensions).”
21.Because aluminium sulphate is less expensive than aluminium hydroxide, dispersion accelerators were initially cheaper than their solution counterparts. However, solution accelerators are generally considered easier to use and a more cost-effective option. The increased aluminium content in solution accelerators improves the initial setting behaviour and early strength development of the shotcrete.[13] This means that these forms of accelerators require a lower dose[14] and have a lower rebound rate[15].
[13] Alfonso at [27] and Myrdal-1 at [20]
[14] Myrdal-1 at [20]
[15] A rebound rate is characterised by a portion of the concrete bouncing back from the substrate – this occurs when setting is too slow and results in poor adhesion to the substrate – see Alfonso at [28]
22.Because of the additional aluminium present in solution as aluminium hydroxide, solution accelerators also generally have a molar ratio of Al:SO4 of above 0.70. Both parties agreed that an Al:SO4 range between 0.67 and 1.2 would provide the right balance between fast setting and good development of compressive strength in solutions[16]. As a consequence (and this was not disputed), solution accelerators would normally have a molar ratio of aluminium to sulphate within the claimed range of 1.35 to 0.70.
[16] Myrdal-2 at [3f]
23.Storage stability was a known problem with both dispersions and solutions containing aluminium sulphate but the underlying issues (and therefore their means of resolution) in the two forms were different. To stabilise a solution containing aluminium sulphate and aluminium hydroxide, it was known to add large amounts of acids such as formic acid or hydrofluoric acid [17]. Several of the commercial products referred to by the applicant (Meyco® SA 162, Meyco® SA 164 and Mapequick® 2000) all containing 3-4% by weight HF[18]. Other common additives were carboxylic and phosphoric acids[19] (the former being mentioned in the opposed specification).
[17] Alfonso-1 at [41], [43(ii)] and [46]
[18] Alfonso-1 at [51]
[19] Myrdal-1 at [22]-[25]
24.To stabilise a dispersion, it was known to use rheological additives (such as magnesium silicates), the most common of which was sepiolite[20]. The applicant conceded that this was known but questioned whether this was part of the CGK. The applicant’s expert (Dr Alfonso) argued that the only publications she was aware of which used sepiolite were 3 patent documents which the opponent provided (D2, D5 and D6) but she did not believe these documents formed part of the CGK:[21]
[20]Myrdal-1 at [27]
[21] Alfonso at [49]
D2: EP 0812812-A1 (MBT Holding AG) published 17 December 1997;
D5 US 6423133 (Touzet et al) published 23 July 2002;
D6 US 6136867 (Frouin et al) published 24 October 2000.
25.I note that the outcome of this decision will not turn on whether sepiolite was (or wasn’t) a well-known stabiliser. There is no suggestion that the applicant was first to recognise the stabilisation properties of sepiolite in accelerators. D2 in particular, specifically highlights these properties (see page 3, line 1). Thus, even if sepiolite was not considered a well-known stabiliser, it merely means that the inventive step determination would be based on a combination of CGK with D2 (rather than CGK alone). Further (as will become evident later in this decision), both parties agree that the key inventive step question in this case is whether the skilled person was directly led to add extra aluminium to a suspension containing high levels of aluminium sulphate. The use of sepiolite to stabilise such suspensions is a secondary consideration which only becomes relevant if the claims fail this primary test.
26.With regard to whether sepiolite was (or was not) a well-known stabiliser, this is a difficult question to answer. The evidence as a whole suggests that the underlying causes of instability in dispersions (and their means of resolution) were well-known at the priority date. As the applicant’s expert (Dr Alfonso) explains[22]:
[22] Alfonso-1 at [39]
“Aluminium sulphate dispersions are thermodynamically unstable. The particles in suspension are subjected to different forces that push the particles against one another, forming larger-size agglomerates which settle to the bottom. Long-term stabilization of the dispersed aluminium sulphate particles in the formulation of a stable suspension may be achieved through both (a) mechanical energy (impact and shear forces), the agglomerates are broken up and disrupted into smaller units and (b) using rheology additives to prevent the formation of larger agglomerates. To my knowledge, at the priority date of the opposed application, only bentonite and sepiolite were disclosed as stabilizers in alkali-free accelerator formulations based on aluminium sulphate dispersions.”
27.I have inferred from her comments that sepiolite was one of a limited number of reported stabilisers which could resolve the (known) instability problems in accelerator dispersions. This would be a reasonable assumption given that sepiolite is a well-known product and its properties would have been well-understood at the priority date. Dr Myrdal also appears to have recognised sepiolite’s role as a general suspension stabiliser[23]:
[23] Myrdal-1 at [27]
“The skilled person would have had an overall and general knowledge of the rheological additives, which were used to stabilise suspension/slurry formulations. These were commonly magnesium silicates of various types, and of particular importance to this patent application, sepiolite. These products act to prevent or retard the settling out of solid particles in suspension or slurry products.”
28.This combined evidence strongly suggests that that the use of sepiolite to stabilise suspensions (including those containing aluminium sulphate) would have been well-known at the priority date. The applicant challenged this position but did not provide any substantive reasons supporting their contrary view. Nonetheless, the opponent did not provide any corroborative evidence of sepiolite being routinely used in alkali-free accelerator (or any) dispersion products at the priority date of the opposed specification[24]. The only general reference[25] which mentioned that sepiolite was a well-known additive in shotcrete referred to its role in increasing the viscosity and improving the thixotropic properties of the shotcrete[26] rather than stabilising the accelerator dispersion (see page 34, column 1, last paragraph et seq).
[24] In fact, the opponent did not provide any evidence that sepiolite was routinely added to commercial suspension products at the priority date The only material safety data sheet for a commercial suspension product provided by the opponent was Meyco-160 (attached to Myrdal-4) does not contain sepiolite
[25] “Sepiolite The Spanish special clay” by J.Santarén Industrial Clays 1996: 27-35 (exhibit RM-5)
[26] Increasing the viscosity gives rise to a more elastic application surface where the projected particles can be embedded. This reduces rebound.
29.As a consequence, there may not be quite enough evidence for me to be practically certain that that sepiolite was a well-known suspension stabiliser at the priority date. However I believe this is highly likely to be the case. I will therefore accept the opponent’s argument and proceed on the basis that the stabilisation properties of sepiolite in suspensions were well-known at the priority date (noting that this will not affect the outcome of the decision).
Novelty
30.The question of novelty is determined under the provisions of subsection 7(1) of the Patents Act (Cth). The basic test for novelty is the "reverse infringement test" as set out in Meyers Taylor Pty Ltd v Vicarr Industries [1977] HCA 19; (1977) 137 CLR 228 at page 235 where Aickin J stated:
"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 invention would if the patent were valid, constitute an infringement."
31.Infringement is said to occur where "each and every one of the essential features of that claim have been taken" (Rodi and Wienenberger AG v. Henry Showell Ltd (1969) RPC 367).
32.However, as noted in Pfizer Overseas Pharmaceuticals v Eli Lilly and Company [2005] FCAFC 224 (see paragraphs 311 et seq), it is not sufficient for a citation to contain all the essential features of the claim, there must be “clear and unmistakable” directions to the claimed invention. In that regard, the Full Court referred to three key decisions:
(a) Canadian General Electric Co v Fada Radio Limited [1930] AC 97:
“...it is not enough to prove that an apparatus described in an earlier specification could have been used to produce this or that result. It must also be shown that the specification contains clear and unmistakeable directions to use it.”
(b) General Tire & Rubber Co v Firestone Tyre and Rubber Co Ltd [1972] RPC 45:
“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”
(c) ICI Chemicals v Lubrizol Corp [2000] FCA 1349; (2000) 106 FCR 214
‘... skilled addressees are not required to rummage through the prior patentee’s "flag locker" to find a "flag which the [prior patentee] possessed and could have planted".’
33.Novelty can however be found where a feature is not explicitly mentioned but nonetheless present as an inherent feature as an inevitable result of the disclosure. As noted in General Tire & Rubber Co v Firestone Tyre & Rubber Co Ltd [supra] at page 486:
"if in carrying out the directions contained in a prior inventor's publication will inevitably result in something being made or done which, if the claim of the opposed specification were a claim of a valid patent, would constitute an infringement of that claim, then that claim would have been anticipated".
34.However as also observed by the same Court:
“ 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 that would not do so, the patentee's claim will not be anticipated."
Relevant art
35.The opponent raised one document under the ground of novelty
D2: EP 0812812-A1 (MBT Holding AG) published 17 December 1997.
36.D2 was discussed as part of the admitted prior art of the opposed specification. It discloses an aqueous dispersion for use as a shotcrete accelerator containing aluminium sulphate and at least one alkanolamine. Diethanolamine (DEA) and triethanolamine (TEA) are among the preferred alkanolamines.[27]
[27] D2 at page 2, lines 27-28
37.D2 does not specify a range of aluminium sulphate concentrations which should be used. However (as noted by Dr Myrdal[28]), the solubility of aluminium sulphate in water is 36g/100cm3. The skilled worker would commonly dissolve aluminium sulphate in concentrations slightly below this level for solution formulations to slightly above this level for dispersions. The three preparation examples respectively contain 60%, 63%, and 63% aluminium sulphate (17% Al2O3 grade) which corresponds to 34-36% anhydrous aluminium sulphate in each preparation[29]. This falls within the aluminium range defined in claim 1 (25-40%).
[28] Myrdal-1 at [19(a)]
[29] See calculation provided for example 1 at Myrdal-1 at [72]
38.In a preferred embodiment the dispersion in D2 contains sepiolite (magnesium silicate) as a stabiliser.[30] Preparation example 1 (which provides the best compressive strength) contains sepiolite and D2 specifically notes at paragraph [0015] that:
[30] D2 at page 2, lines 55-59
“It has been found that sepiolite works particularly well in this invention. It is preferably used in the proportion of from 0.1 to 10.0% by weight of the admixture.”
39.The applicant argued that the difference between D2 and the current claims is the molar ratio of aluminium to sulphate. Aluminium sulphate on its own has an Al/SO4 molar ratio of 0.67 and thus there needs to be an additional aluminium compound to change this proportion to fall with the claimed range (ie: 1.35 to 0.70). In contrast to the opposed specification, the citation teaches away from the addition of aluminium hydroxide (Al(OH)2)[31]. Nonetheless the citation notes that final strength of the shotcrete can be improved by the addition of at least one additional water-soluble salt in the accelerator. The preferred salt listed is ferric sulphate but the citation notes that other salts including ferric nitrate and aluminium nitrate can be used. The proportion of salt added may be up to 20% maximum (preferably 10% maximum)[32]. The opponent’s expert (Dr Myrdal) calculated that adding 20% aluminium nitrate (by weight of the aluminium sulphate + aluminium nitrate) would give the dispersion an Al/SO4 ratio of 0.80[33] which falls within the scope of the claims (1.35 to 0.7).
[31] D2 at page 2, lines 20
[32] D2 at page 2, lines 23-26
[33] Myrdal-1 at [73]
40.However, while the citation teaches that aluminium nitrate could be added to the dispersion, the skilled worker would be at least as likely to use another salt (particularly the preferred salt ferric sulphate) which would not lead to the same result. In addition, none of the examples in D2 use aluminium nitrate (or indeed any additional salt). As a consequence, the citation does not provide “clear and unmistakeable directions” to produce a dispersion where the molar ratio of aluminium to sulphate is from 1.35 to 0.70 and hence all the claims are novel in light of D2.
Inventive step
Relevant Law
41.Section 7(2) provides that an invention is taken to involve an inventive step when compared to the prior art base unless it would have been obvious to a person skilled in the relevant art in the light of common general knowledge within Australia either considered alone or together with information made publicly available anywhere in the world. Section 7(3) restricts the information to that which could be reasonably expected to have been ascertained, understood and regarded as relevant by the person skilled in the relevant art.
42.Inventive step may be assessed having regard to the reformulated so-called “Cripps question” set out in Aktiebolaget Hassle v Alphapharm Pty Limited [2002] HCA 59; 212 CLR 411 at [53]:
“Would the notional research group at the relevant date in all the circumstances … directly be led as a matter of course to try [the claimed invention] in the expectation that it might well produce [the desired result]?”
43.To provide some context to that question, the Courts commonly determine the “starting point” for consideration of inventive step in terms of an existing problem for which the inventor found a solution. As noted by High Court in Lockwood Security Products Pty Ltd v Doric Products Pty Ltd (no. 2) [2007] HCA 21 at [105]:
“While not every invention constitutes a solution to a problem, it is commonplace so to describe an invention where is appropriate to do so”
44.Recent Federal Court decisions have followed this approach. Thus in Ranbaxy Laboratories Ltd v AstraZeneca AB [2013] FCA 368 (23 April 2013) ([203]-[218]), Justice Middleton cited Jagot J’s comments in Apotex Pty Ltd v AstraZeneca AB (No 4) [2013] FCA 162 with approval:
“In assessing obviousness, it is necessary first to determine the nature of the claimed invention and the inventive step described in the Patent. This may involve ascertaining the “starting point” of the inventive step, sometimes described in terms of an existing problem for which the inventor found a solution. The obviousness of the invention as claimed is then assessed by reference to common general knowledge in Australia at the priority date.”
Problem to be solved
45.The problem for the invention is to provide an accelerator for air-placed concrete and pneumatically applied mortar that:
(a) exhibits rapid setting behaviour and very good early strength;
(b) achieves comprehensive strength after a few hours (early strength) which is maintained after several days (later strength); and
(c) has sufficient storage stability.
Inventive step based on the CGK alone
46.The difference between the current claims and the CGK are that the claims define a dispersion (suspension) containing a specific proportion of aluminium/sulphate (1.35 to 0.70) and also contained an inorganic stabilizer (magnesium silicate). The opponent argued that the skilled worker knew that the aluminium levels were known to be needed to be in a particular range for optimum performance (fast setting, long term strength) and would also have understood that accelerator dispersion suspensions could be stabilised by an inorganic stabiliser. They therefore argued that both differences were a mere optimisation of a known product by a known means which was not inventive[34].
[34] Myrdal-1 at [29], [54] and [61]
47.The applicant suggested that suspensions had effectively been superseded by the easier to use and more cost effective “solution” formulations containing additional aluminium hydroxide. In their view, suspensions were “first generation” products and solutions were “second generation” products. Most of the research effort was concentrated on improving stability in solution[35] and reverting to a stabilised dispersion would go against the background teaching (and general direction) of the art.
[35] Alfonso-1 at [45]
48.I note that if the applicant is correct about a first and second generation product, I would have expected that commercial products used at the priority date would all be solutions. However the opponent provided a material safety data sheet from a well-known commercial product used in January 2006 (Meyco® SA 160) which is clearly a liquid suspension containing aluminium sulphate[36]. The specification itself also appears to acknowledge that the 2 forms co-existed in the market place as known alternatives:
[36] Myrdal-4
“The alkali-free accelerators may be present both in the form of a dispersion and in the form of a solution. What is important is that said dispersions or solutions firstly have a high active substance content and secondly are sufficiently stable – i.e. dispersed or dissolved active substance does not settle out and dissolved accelerator components do not precipitate, crystallise or gel”[37].
[37] Opposed specification at page 2, paragraph 3
49.Thus I am not convinced that the solution product was necessarily a “second generation” product as argued by the applicant. However I accept (and both parties acknowledged) that there were practical differences between solution and dispersion formulations and that the stability problems each would have been approached very differently. In doing so, the skilled worker would aim to prevent precipitation in solutions and to stabilise precipitated solids within a dispersion.
50.Given the two different aims, it seems counter-intuitive to produce a dispersion from a solution. It is therefore not clear that that the person skilled in the art would, when trialling admixtures to provide a stable solution, would suddenly switch their approach to stabilising a dispersion. Rather the person skilled in the art in seeking to stabilise a solution would continue trialling of admixtures to avoid precipitation.
51.There was a single comment in a paper published in 1999 by Dr Myrdal[38] which suggested that some suppliers have developed suspension- or slurry-like products containing Al(OH)3 to avoid the problem of precipitation of solid particles in solution. However there was insufficient detail in the paper for me understand why this was the case and hence I am unable to determine whether this approach was the common thinking at the priority date or would have also been applied to aluminium sulphate formulations containing additional aluminium hydroxide.
[38] “Modern Chemical Admixtures for Shotcrete” in N. Barton et al (eds) Proceedings Third International Symposium on Sprayed Concrete”, Gol, Norway 26-29 September 1999 pp: 373-382 at p 377 [Myrdal-1 (exhibit RM2)]
52.In this regard, I note that additional aluminium hydroxide was added to increase the levels of aluminium in solution. As noted by the applicant, adding aluminium hydroxide to aluminium sulphate in solution at concentrations slightly above saturation forms a supersaturated solution of basic aluminium sulphate complexes of the formula [Al(OH)x(SO4)y(H2O)z]n[39]. Because the skilled worker would understand the purpose of the additional aluminium hydroxide is to form a solution, it is not clear that they would see any benefit of making a dispersion (especially given that aluminium sulphate is a cheaper option and can be can be added to a dispersion at beyond saturation levels).
[39] Alfonso at [41]
53.There may be an explanation for this gap but the opponent has not provided it. As a consequence, it is not clear that the skilled worker would arrive at the claimed solution without the benefit of hindsight. I am therefore unable to conclude that the skilled worker would be directly led from a solution containing aluminium sulphate/hydroxide to a dispersion and the opponent has not established that any of the claims lack an inventive step in light of the CGK alone.
Cited art for inventive step
54.The opponent relied on the following documents in relation to inventive step:
D2: EP 0812812-A1 (admitted prior art) (MBT Holding AG) published 17 December 1997
D4: WO 2005/028398 (Construction Research & Technology GmbH) published 31 March 2005
55.The applicant noted that the opponent did not provide any evidence that Dr Myrdal personally consulted patents in this area as part of his research or that a search (postulated or actual) would have found such documents. Hence they argued that neither of these documents are part of the section 7(3) prior art base for inventive step.[40]
[40] Applicant’s submissions at [37]-[40]
56.However I think it can be reasonably inferred that the skilled worker could have ascertained D2 and D4 at the priority date from the nature of these documents (and the evidence as a whole). D2 is part of the admitted prior art in the opposed specification. This is an active and commercially competitive field in which the skilled worker would need to be abreast of new product developments. In fact, both primary experts have a previous involvement with patents – Dr Myrdal being named as an inventor on 3 patent applications and Dr Alfonso working on projects which resulted in patent applications[41].
[41] Opponent’s submissions at [71]
57.Given the problem of providing an accelerator which is stable, is fast setting and has good strength, the skilled worker would consult the patent literature because this is a well-known source of information about new products. Both D2 and D4 are patent documents from readily searchable data bases. Both documents disclose non-caustic shotcrete accelerators and would have been straight forward to find. Having found these documents, the skilled worker would also understand and regard these documents as relevant. Hence my view is that both documents form part of the section 7(3) prior art base for inventive step.
Inventive step determination based on the cited art
D2 (EP 0812812)
58.As noted above, D2 discloses an aqueous dispersion for use as a shotcrete accelerator containing aluminium sulphate and at least one alkanolamine. In a preferred embodiment the dispersion contains sepiolite (magnesium silicate) as a stabiliser. The difference between the citation and the current claims is that it does not contain clear and unmistakable directions to add a further aluminium compound to the dispersion.
59.As the opponent noted, the citation still listed aluminium nitrate as a component in the dispersion as a specific and preferred embodiment:
“In a further preferred embodiment, the aluminium sulphate may include a proportion of at least one additional water-soluble salt. Such addition can prolong setting time and improve final strength. The preferred salt is ferric sulphate, but other salts, such as ferric nitrate and aluminium nitrate may also be used.” (page 2, lines 23-26)
60.There are no working examples of the addition of any water-soluble salt. Further, while aluminium salt is specifically listed as an alternative, it is amongst several (non-limiting) options. The citation did not recognise the critical importance of aluminium because the other listed options (including the most preferred) contained iron rather than aluminium. There was a selective advantage to using aluminium nitrate and no special inducement to choose this alternative. In fact, the applicant argued that the skilled worker could even be led away from aluminium nitrate because these salts were known to cause corrosion problems[42].
[42] Alfonso at [120]. Applicant’s submissions at [66]
61.Dr Myrdal argued that a skilled person would still understand that the formulation in D2 had been superseded by formulations containing low levels of aluminium hydroxide (typically in the range of 5-10%) to improve early strength development of the cement. According to Dr Myrdal, adding 5-10% by weight aluminium hydroxide would increase the aluminium to sulphate ratio to 0.75-0.83 and would have been an obvious step to take.[43]
[43] Myrdal-1 at [74]
62.However, the citation itself acknowledges that aluminium hydroxide had been used in non-caustic accelerator compositions previously (see page 2, lines 11-12) and noted that their advance was to replace aluminium hydroxide with aluminium sulphate (page 2, lines 18-20). Given this explicit teaching, it is difficult to see how the skilled worker could be led to then add aluminium hydroxide without the benefit of hindsight.
63.As a consequence, the opponent has not established that any of the claims lack inventive step in light of D2.
D4 (WO 2005/028398)
64.D4 was published in May 2005 (about 14 months before the priority date of the opposed application). D4 discloses a liquid accelerator composed of a fluoride-containing aqueous aluminium salt obtained by reacting aluminium sulphate and hydrofluoric acid, aluminium hydroxide and one or more lithium salts selected from the group consisting of lithium hydroxides, lithium carbonates and lithium sulphates. The fluoride-containing aqueous aluminium salt provides a good spraying workability without raising the initial accelerating effect too high[44]. The lithium salts enable the total alkali of the accelerator to be reduced (addressing the safety and environmental issues of using alkali reactors). The key embodiment (invention sample 9) contains 25% aluminium sulphate and a further aluminium compound (aluminium hydroxide) at 2% which results in an aluminium to sulphate ratio of 0.78[45].
[44] Applicant’s submissions at [43]
[45] Opponent’s submissions at [74(f)]
65.The difference between D4 and the current claims is that it discloses an accelerator solution rather than a dispersion and that there is no inorganic stabiliser. However the opponent provided some experimental data which reproduced the conditions in invention sample 9 and found that it resulted in a suspension (dispersion) rather than a solution[46]. According to the opponent, the skilled worker would then be directly led to stabilise this suspension from their CGK using an inorganic stabiliser.
[46] Opponent’s submissions at [74 (c)]; Myrdal-2 at [23], RM-4
66.However the stated aim of the invention in D4 is to improve storage stability of a liquid accelerator at low temperatures[47] which is achieved by eliminating crystalline precipitation[48]. D4 specifically teaches that invention sample 9 has a good solution stability without crystal precipitation even at low temperatures for a long period[49]. Given this clear and precise teaching, the skilled worker is clearly directed to make a solution and taught away from a suspension. If mixing the ingredients produced the latter, the skilled worker would therefore try to clarify the solution rather than stabilise the suspension (as discussed above). The skilled worker would therefore not be directly led to the claimed invention and the opponent has not established that the claims lack an inventive step in light of D4.
[47] D4 at [0006]
[48] D4 at [0014]
[49] D4 at p [0033]
Inventive step based on a combination of D2 or D4 and the common general knowledge
67.The opponent argued that a combination of D2 or D4 with the common general knowledge could deprive the current claims of their inventive step. However these combinations do not add anything to the opponent’s inventive step case already discussed above.
68.D4 clearly teaches away from using dispersions and there would be no motivation from this document of the CGK to make a dispersion as defined in any of the claims. D2 discloses a dispersion containing aluminium sulphate and an inorganic stabiliser. It does not teach an increased level of aluminium in dispersions and there is insufficient evidence to show that the skilled worker would have been motivated to use this approach based on previous success with solutions (where there were slightly different problems). As a consequence, the opponent has not established that any of the claims lack inventive step based on a combination of either D2 or D4 and the common general knowledge.
Conclusion
69.All the claims are novel and inventive in light of the prior art raised by the opponent and none of the grounds of opposition have been made out. Subject to appeal, I direct this application proceed to sealing.
Costs
70.The opposition is unsuccessful. Accordingly I award costs in accordance with Schedule 8 of the Patents Regulations 1991 against the opponent, Xylotheque Ltd.
Karen Ayers
Delegate of the Commissioner of Patents
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