Imperial Chemical Industries PLC v the Lubrizol Corporation and E.I. Du Pont De Nemours and Co
[1999] APO 62
•11 October 1999
OFFICIAL NOTICE
DECISION OF A DELEGATE OF THE COMMISSIONER OF PATENTS
Application : No. 658005 in the name of Imperial Chemical Industries PLC
Title: Lubricants
Action: Oppositions under section 59 by The Lubrizol Corporation and E.I. Du Pont De Nemours and Company
Decision: Issued
Abstract
The opposition fails on all grounds.
a)The application is entitled to priority from the basic document. The changes from the basic document can be regarded as a working out of material broadly described in the basic document.
Coopers Animal Health Australia Ltd v Western Stock Distributors Pty Ltd (1987) 15 FCR 382 applied.
b)The application is novel. The citation discloses mixtures selected from specifically identified HFC's. The key HFC's (R-32 and R-125) are not specifically referred to, and the specification does not suggest mixtures including these particular refrigerants.
Meyers Taylor Pty Ltd v Vicarr Industries Ltd (1977) 137 CLR 228 followed.
c)The application is not obvious. The problem-solution approach is applied.
Rhone-Poulenc Rorer S.A.'s Application [1995] APO 50 followed.
If a document is published in Australia, it is prima facie reasonable to expect it to have been ascertained. On the other hand, when a document is not available in Australia, it is inherently unreasonable to expect the document to have been ascertained. Both presumptions are open to rebuttal.
d)The application is a manner of manufacture. On the face of the specification, there is an advantage possessed by the combination of components. The mixture is more than a mere collocation due to the miscibility result.
NV Philips Gloeilampenfabrieken v Mirabella International Ltd (1995) 183 CLR 655 and Commissioner of Patents v Microcell Ltd (1959) 102 CLR 232 applied.
PATENTS ACT 1990
DECISION OF A DELEGATE OF THE COMMISSIONER OF PATENTS
Re:Patent Application No. 658005 by Imperial Chemical Industries PLC, and oppositions under section 59 by The Lubrizol Corporation and E.I. Du Pont De Nemours and Company.
BACKGROUND
Patent application 26242/92 in the name of Imperial Chemical Industries PLC (hereafter referred to as ICI) was filed on 6 October 1992, claiming priority from two basic applications: GB 9121657 dated 11 October 1991, and GB 9215602 dated 22 July 1992. Following examination by the Commissioner, the application was advertised accepted on 30 March 1995 under the serial number 658005.
On 30 June 1995 two separate notices of opposition were filed, one by The Lubrizol Corporation (hereafter referred to as Lubrizol) and the other by E.I. Du Pont De Nemours and Company (hereafter referred to as Du Pont). Statements of grounds and particulars were filed on 2 October 1995. The Lubrizol statement of grounds and particulars was amended on 22 April 1996. The ICI statement of grounds and particulars was amended twice, the last occasion being on 19 February 1996. The service of evidence in the Lubrizol opposition was completed on 30 October 1998. The service of evidence in the Du Pont opposition was completed on 23 October 1998.
The oppositions were heard together, with the agreement of the parties, in Sydney on 7 and 8 July 1999. ICI was represented by Mr David Catterns QC instructed by Mr Ray Evans, patent attorney of Phillips Ormonde & Fitzpatrick, Melbourne. Lubrizol and Du Pont were represented by Mr Justin Gleeson of counsel, instructed by Dr Elizabeth Sutherland, patent attorney of Callinan Lawrie, Melbourne.
THE GROUNDS OF OPPOSITION
The patent application was filed under the Patents Act 1990. Consequently, the present oppositions are governed by section 59 of the Act and Chapter 5 of the Regulations. The statements of grounds and particulars identify the same grounds of opposition:
ØManner of manufacture;
ØNovelty;
ØInventive step; and
ØSection 40 matters.
The section 40 grounds were not pursued at the hearing. The two oppositions were argued together by Mr Gleeson.
THE SPECIFICATION
Background to the invention
The specification relates to heat transfer compositions for heat transfer devices (such as refrigerators and air conditioners), comprised of a lubricant and a heat transfer fluid (also referred to as a refrigerant). Heat transfer devices operate by circulating the refrigerant within a closed system. In one zone, the refrigerant takes in heat from the environment and evaporates at low pressure. In another zone the vapour condenses and gives off heat. The condensate is then returned through an expansion valve to the evaporation zone. The refrigerant is circulated by means of a pump or compressor. The operation of heat transfer devices of the type involved in the present application are described by Emmett J in ICI Chemicals & Polymers Ltd v Lubrizol Corp Inc [1999] FCA 345 (the first Lubrizol decision) at [8] to [33]. The refrigerants traditionally include chlorofluorocarbons (known as CFC's). Heat transfer devices frequently utilise lubricants such as mineral oils in conjunction with the circulating refrigerant. The solubility of mineral oils in CFC's allows the mineral oil to circulate around the heat transfer device together with the CFC, which provides proper lubrication of the compressor.
However, CFC's have been implicated in the destruction of the ozone layer, and their use is limited by international agreement. Consequently there is a need for a CFC-free heat transfer composition.
A table of the designation codes used in relation to refrigerant fluids is given in Annex 1 of this decision.
The consistory statement
The present specification provides a heat transfer composition (referred to as a "working fluid composition") comprising:
(A)a refrigerant comprising a mixture of at least two hydrofluoroalkanes (known as HFC's) selected from the group consisting of difluoromethane (R-32), 1,1,1,2-tetrafluoroethane (R-134a) and pentafluoroethane (R-125); and
(B)a lubricant which is at least partially soluble in each component of the refrigerant, said lubricant comprising one or more compounds of general formula:
R(O-C(=O)-R1)n II
wherein
R is the hydrocarbon radical remaining after removing the hydroxyl groups from pentaerythritol, dipentaerythritol, tripentaerythritol, trimethylol ethane, trimethylol propane or neopentyl glycol, or the hydroxyl containing hydrocarbon radical remaining after removing a proportion of the hydroxyl groups from pentaerythritol, dipentaerythritol, tripentaerythritol, trimethylol ethane, trimethylol propane or neopentyl glycol;
each R1 is, independently, H, a straight chain (linear) aliphatic hydrocarbyl group, a branched aliphatic hydrocarbyl group, or an aliphatic hydrocarbyl group (linear or branched) containing a carboxylic acid or carboxylic acid ester substituent, provided that at least one R1 group is a linear aliphatic hydrocarbyl group or a branched aliphatic hydrocarbyl group; and
n is an integer.
The body of the description
The specification discusses binary and ternary refrigerant mixtures of R-32, R-134a and R-125, and polyol ester lubricants. Optional additives in the composition are polyalkylene glycols (a co-lubricant), corrosion inhibitors, thermal stability improvers, metal deactivators, viscosity index improvers, anti-wear agents and extreme pressure resistance additives. The description ends with 5 examples. The first example reproduces the Tables from the basic document GB 9121657 (which relate to R-134a/32 and R-125) with some explanatory description. The other examples involve the binary mixture R-134a/32 and the ternary mixture R-134a/32/125.
The claims
The claims of the specification are reproduced in full in Annex 2. In approaching the construction of the claims I am conscious of the need to construe terms in the context of the specification and the state of the art: "one should not pick one’s way through a claim wearing blinkers that exclude from sight the context in which the claim is set. In the modern cases, it is frequently said that a specification should be given a purposive construction rather than a purely literal one" (International Business Machines Corp v Commissioner of Patents (1991) 22 IPR 417 at 421).
Claim 1 is the only independent claim. The claim is directed to a composition "comprising" two components, designated A and B. I consider that in the context of a composition of a refrigerant and lubricant, it is reasonable to construe the composition as including other standard additives (such as antioxidants). Thus I construe "comprising" in an inclusive sense.
Component A is a "heat transfer fluid". This is another name for a refrigerant. The refrigerant is defined as "comprising" a mixture of at least two named HFC's. The term "comprising" in this context could be either inclusive or exclusive. From the prior art and evidence filed in relation to this opposition it is apparent to me that mixtures of refrigerants are used in this art, but that mixtures of large numbers of refrigerants are not normal. It seems reasonable that the component A is limited to the specified HFC's. Thus "comprising" is used in an exclusive sense in this instance.
Component A can be summarised as:
Øa blend of two or three of R-32, R-134a and R-125.
Component B is a lubricant which is defined as (i) "which is at least partially soluble in each component" of A, and then defined as (ii) "said lubricant comprising" one or more compounds of formula II. The first question is whether the lubricants are compounds of the formula II (all of which are at least partially soluble in each refrigerant), or whether the lubricants are compounds of formula II provided they are at least partially soluble in each refrigerant.
Looking first at the words of the claim, component B is defined as "a lubricant which is" limited by requirement (i). It is clear that the lubricant must satisfy the partial solubility requirement (i). The structural requirement (ii) is introduced by the words "said lubricant comprising". I construe "said lubricant" to be the lubricant as already defined, which is a lubricant satisfying the partial solubility requirement (i). The structural requirement (ii) is a second limitation which follows after selecting the lubricants meeting the partial solubility requirement (i). This is not the same as saying that all compounds of formula II would satisfy the partial solubility requirement (i). It follows that the correct construction of the lubricant B is that there are two requirements that must be satisfied: a partial solubility requirement (i), and a structural requirement (ii).
The structural requirement (ii) specifies "comprising one or more compounds of general formula". The term "comprising" in this context could be inclusive or exclusive. However, lubricants are often mixtures of compounds, so it would be expected that "comprising" is used in an inclusive sense. However, any co-lubricant falling outside the structural requirement (ii) would still have to satisfy the partial solubility requirement (i). I would not expect such a co-lubricant to constitute a major proportion of the total lubricant.
PRIORITY DATES OF THE CLAIMS
The priority date of the claims of the opposed specification was the subject of detailed submissions by counsel.
The relevant law
The priority date of the claims is determined by section 43(2), which states:
"(2) The priority date of a claim is:
(a) the date of filing of the specification; or(b)where the regulations provide for the determination of a different date as the priority date - the date determined under the regulations."
Consequently, the starting point is the date of filing of the specification. In the present case the application is a Convention application, and the regulations provide for a different priority date. The relevant regulation is 3.12:
"3.12 (1) Subject to regulations 3.13 ("priority dates: certain persons and applications") and 3.14 ("priority dates: certain amended claims") and subregulation (2), the priority date of a claim of a specification is the earliest of the following dates:
(a) the date of filing of the specification;
(b)if the claim is fairly based on matter disclosed in 1 or more priority documents, the date of filing the priority document in which the matter was first disclosed; …
(2) For the purposes of paragraph (1)(b): …
(b)if the application that relates to the specification containing the claim is a Convention application, a document of any of the following kinds is a priority document:
(i)a basic application that is related to the Convention application;"
Thus a claim takes the filing date of the priority document as its priority date if it is fairly based on that priority document. The fair basis test for priority can be expressed as a "real and reasonably clear disclosure" test (F.Hoffman-La Roche & Co Aktiengesellschaft v Commissioner of Patents (1971) 123 CLR 529 at 539). In approaching this task, the courts have recognised that priority documents have a different role to that of complete specifications. In Coopers Animal Health Australia Ltd v Western Stock Distributors Pty Ltd (1987) 15 FCR 382 at 389, Fox J (with whom Spender J agreed) stated in relation to provisional specifications:
"Where the holder of the provisional specification proceeds with a complete specification with a view to the grant of a patent, it is recognised that greater definition, as a result of further experimentation or otherwise, may be achieved before the later step is taken and the result expressed therein. Some generality of expression in the provisional specification is accepted. In language which he would not have used as a definition, but is nevertheless a guide, Lloyd-Jacob J in Imperial Chemical Industries Ltd (Clark's Application) [1969] RPC 574 at 583 said of the function of a provisional specification that it is: '…a description of the general nature of the invention, its field of application and the anticipated result.' … The fact that there may be a further working out of details before the complete specification is lodged does not mean that the provisional specification can always be used as giving a priority date to something which is worked out and contained in the specification. In particular, the selection of one compound with special qualities from a class of compounds disclosed in the provisional is not permissible for that purpose"
In Hoffman-La Roche v Commissioner at 544 Gibbs J accepted that the opportunity for development is applicable to both provisional applications and Convention applications. It is clear that a basic document can be expressed in more general language than the complete specification, and it is legitimate for there to be some development between the basic document and the complete specification. However, the development cannot be such as to amount to a different invention. This is made very clear in Stauffer Chemical Co.'s Application [1977] RPC 33 (quoted in CCOM Pty Ltd v Jiejing Pty Ltd (1994) 28 IPR 481 at 501):
"If a new feature were a development along the same line of thought which constitutes or underlies the invention described in the earlier document, it might be that that development could properly be regarded as fairly based on the matter disclosed in the earlier document, and that the new process described in the later document which incorporates that development could as a whole be regarded as fairly based upon the matter disclosed in the earlier document. If, on the other hand, the additional feature involves a new inventive step or brings something new into the combination which represents a departure from the idea of the invention described in the earlier document, it could not, I think, be properly described as fairly based upon the earlier document."
Mr Gleeson suggested that the claims cannot be fairly based on the basic document if the basic document is cast in broader terms than the claims. This submission was based on the decision of Emmett J in ICI Chemicals & Polymers Ltd v Lubrizol Corp Inc [1999] FCA 662 (the second Lubrizol decision). In the second Lubrizol decision some claims had been abandoned but there had been no corresponding amendment to the body of the description. It was found that the amended claims were not fairly based on the unamended description because the description was inconsistent with the remaining claims: "a real tension between the disclosure of the invention in the body of the Specification and the delimitation of the invention in the Remaining Claims" (paragraph 44). This is reminiscent of the situation in the Coopers case, where DGBE was mentioned in the body of the description but not in the way that it was ultimately claimed, leading to a loss of priority. I do not believe that the second Lubrizol decision alters the approach I have outlined.
If the application is not entitled to priority from the basic document, it will take the date of filing as its priority date unless the claimed subject matter was included in the specification as a result of a later amendment (section 114, and regulation 3.14). It is possible for different aspects of a claim to be accorded different priority dates (section 43(3)).
GB 9121657
The starting point is to ascertain the invention that is described in this basic document. The basic document relates to lubricants for heat transfer devices, and heat transfer compositions containing these lubricants. The conventional hydrochlorofluorocarbon refrigerants (known as HCFC's) are damaging to the ozone layer (page 1, lines 19 to 21). Consequently, it "has been proposed" (lines 21 to 22) to use HFC's in place of HCFC's. R-134a is being used as a replacement for R-12, but mineral oil lubricants are not miscible with R-134a (line 27 to 29). New lubricants are needed, and "esters of polyhydroxy alcohols with mono and polyfunctional acids" (lines 31 to 32) have been proposed. R-134a cannot be used as a replacement for R-22 or R-502 because it has different boiling point characteristics, and mixtures of refrigerants have been proposed (page 2, lines 3 to 6).
It was not possible to predict whether a lubricant will be miscible with a refrigerant mixture (lines 9 to 15). The solution to this problem is that if a lubricant is at least partially soluble in each component of a mixture, the lubricant will be at least partially soluble in the mixture and be useful as a lubricant (lines 16 to 22).
The invention is then described as a composition of two components:
(a)a working fluid (or refrigerant) comprising a mixture of at least two components, wherein each component is a hydrofluoroalkane (HFC) or a fluoroalkane; and
(b)a lubricant which is at least partially soluble in each component (lines 23 to 29).
The refrigerant is described as:
Øa mixture of two, three or more components (line 31);
Øsuitably the components are selected from R-134a, R-125 and R-32 (line 33); and
Øreplacements for R-22 may be R-134a/32 or R-125/32 (line 34 to page 3 line1).
The lubricant is described as:
Øthose currently used with R-134a (page 3, lines 2 to 3);
Øparticularly effective lubricants are selected from a group including neopentyl polyol esters (line 6);
Øsuitable neopentyl polyol esters include esters of tri, di and mono pentaerythritol, trimethylolpropane, trimethylolethane and neopentylglycol with acids such as linear and/or branched aliphatic carboxylic acids (lines 8 to 13); and
Ølubricants suitable for use in higher temperature applications (lines 16 to 31).
Two examples are given on pages 4 and 5. First, a mixture of R-134a/32 (equal proportions by weight) and commercially available lubricants is exemplified, and the miscibility of the lubricant in the HFC is determined (page 4 lines 4 to 31). Second, a mixture of R-125 and the same commercially available lubricants is exemplified (page 4 line 32 to page 5 line 9).
It seems clear that this basic document discloses heat transfer compositions wherein an HFC mixture is used in combination with an ester lubricant. A binary HFC mixture is clearly exemplified, and more components are envisaged (page 2 line 31). The use of R-134a, R-125 and R-32 as the refrigerant HFC's is explicit (page 2 line 33).
The present claims differ from the basic document in several regards. These are:
a) The refrigerant is restricted to R-32, R-134a and R-125 mixtures
The basic document suggests binary and higher mixtures of HFC's and fluorocarbons, and specifically refers to R-32, R-134a and R-125. Focussing on R-32, R-134a and R-125 seems to be a legitimate focussing on a part of the material that is broadly described in the basic document.
b) The lubricant is identified by a chemical formula
A major change is the introduction of a chemical formula to represent the lubricant. Mr Catterns submitted that this is only a translation of the words of the basic document into a pictorial form. This suggestion is easily tested.
The R part of the ester is described in the basic document at page 3 lines 8 to 10. This is exactly the same range of groups as that given in claim 1. The R1 part of the ester is described at page 3 lines 10 to 13 of the basic document. This seems to be the same range of groups as that given in claim 1. However, claim 1 contains the proviso: "provided that at least one R1 group is a linear aliphatic hydrocarbyl group or a branched aliphatic hydrocarbyl group". This is a narrowing of the claim which seems to reflect the lubricants that are thermally stable at elevated temperatures (page 3 lines 16 to 31). The variable n is not discussed in the basic document. The exemplified esters (PE6, EMKARATE and EMKAROX) appear to mixtures rather than single compounds, so it is reasonable to expect that the basic document is concerned with esters containing one or more esterified alcohol groups. This is consistent with values of n given in claim 1.
The formula II seems to be no more than a pictorial representation of the description of the lubricant given in the basic document.
c)Polyalkylene glycol ethers are no longer identified as lubricants (other than as optional additional lubricants)
The basic document identifies polyalkylene glycols as suitable lubricants (page 3 line 5, and lines 31 to 35). The present specification has been drafted so as to exclude the polyalkylene glycols, other than as optional co-lubricants. This seems to be a narrowing in on one form of the invention.
d) The partial solubility of the lubricant in the refrigerants is presented in a different manner
In the basic document the lubricant must be one that is at least partially soluble in each component of the refrigerant (for example, page 2 line 29, page 3 lines 3 to 4, page 4 lines 12 to 14). Mr Gleeson submitted that this requirement has now been dropped in favour of the structural formula II. In my construction of claim 1 (above) I concluded that the partial solubility requirement is still present, in addition to the structural formula requirement. Consequently, this feature has not been lost, it is merely presented in different words.
Mr Gleeson suggested that the changes amounted to a new inventive concept. I consider that the changes can be regarded as a working out of material broadly described in the basic document. In particular, Mr Gleeson considered that the partial solubility test was the touchstone of the basic document, but suggested it had been downgraded in the present claims. That touchstone is still present, and is an essential feature of the invention as claimed. Only the form of words used in relation to this feature has changed, which does not make it a different invention.
As explained above, the present claimed invention can be viewed as a legitimate working out of the general principle described in the basic document. The claims are entitled to priority from GB 9121657, and thus take 11 October 1991 as their priority date. In this situation it is not necessary to consider whether the second basic document also provides support for the present claims.
NOVELTY
At the hearing the opponents relied on only one document for the ground of novelty: Australian patent application 54480/90 in the name of Lubrizol Corporation (hereafter referred to as the Lubrizol patent). The Lubrizol patent is particularised in both statements of grounds and particulars. The Lubrizol patent was available to the public in Australia on 16 November 1990, which is prior to the earliest priority date of the present application.
The relevant law
The test for novelty is the reverse infringement test. The classic formulation of this test is that given by Aickin J in Meyers Taylor Pty Ltd v Vicarr Industries Ltd (1977) 137 CLR 228 at 235:
"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."
A more recent summary of the law on novelty is in Nicaro Holdings Pty Ltd v Martin Engineering Co (1990) 91 ALR 513 at 517:
"It is well accepted that the prior art must disclose all features of the invention embodied in the patent in suit and must do so in clear, unequivocal and unmistakable terms. The prior art must enable the notionally skilled addressee at once to perceive and understand and be able practically to apply the discovery without the necessity of making further experiments. Whatever is essential to the invention must be read out of or gleaned from the prior publications"
In order to apply the reverse infringement test it is necessary to determine the disclosure of the citation, and then decide whether that subject matter would infringe the claims of the application under opposition. The disclosure of the citation is referred to in the classic statement of Sach LJ in General Tire & Rubber Co v Firestone Tyre & Rubber Co Ltd [1972] RPC 457 at 485 - 486 in the terms:
"a signpost, however clear, upon the road to the patentee's invention will not suffice. A prior inventor must be clearly shown to have planted his flag at the precise destination before the patentee."
The question of the disclosure of a citation, or the area where the prior inventor has planted his flag, is not to be confused with the scope of the claims of the citation. Mr Gleeson agreed that the disclosure of a citation is a question of the technical disclosure of the document. In Pharmacia Aktiebolag v Ueno Fine Chemicals Industry Ltd (1995) 34 IPR 445 I adopted such an approach, and stated that a distinction needs to be drawn between the intellectual content of a chemical shorthand (i.e. the materials encompassed by the shorthand) and the technical information that the citation would make public to the instructed reader (though not necessarily revealed in every detail).
The disclosure of the Lubrizol patent
The Lubrizol patent discloses heat transfer compositions which are described in the consistory statement as:
"A liquid composition is described which comprises
(A) a major amount of at least one fluorine containing hydrocarbon containing one or two carbon atoms; and
(B) a minor amount of at least one soluble organic lubricant comprising at least one carboxylic ester of a polyhydroxy compound containing at least 2 hydroxy groups and characterised by the general formula
R[OC(O)R1]n (I)
wherein R is a hydrocarbyl group, each R1 is independently hydrogen, a straight chain lower hydrocarbyl group, a branched chain hydrocarbyl group, or a straight chain hydrocarbyl group containing from 8 to about 22 carbon atoms provided that at least one R1 group is hydrogen, a lower straight chain hydrocarbyl or a branched chain hydrocarbyl group, or a carboxylic acid- or carboxylic acid ester-containing hydrocarbyl group, and n is at least 2."
Mr Catterns conceded that the lubricants of component (B) are the same as those of the present specification. The question is whether the anticipation discloses a refrigerant component (A) (in combination with the component (B)) that is the same as that claimed in the present application.
The expression "at least one fluorine containing hydrocarbon containing one or two carbon atoms" is a shorthand way of specifying a huge range of refrigerant compositions. It is clear that as a purely intellectual exercise, this includes the mixtures of HFC's that are claimed as component (A) of claim 1 of the present application. Thus the intellectual component of the Lubrizol patent encompasses the present claims. But this is not sufficient to establish lack of novelty. In order to determine where the Lubrizol patent has planted its flag, it is necessary to ask what refrigerant compositions would the Lubrizol patent make public to the instructed reader. For this purpose it is necessary to look to the body of the description.
From page 8 to page 10 there is a description under the heading "(A) Fluorine-Containing Hydrocarbon", which is the preferred embodiment in relation to the fluorocarbon. The relevant portions of this description read:
"The liquid compositions of the present invention comprise a major amount of at least one fluorine-containing hydrocarbon. That is, the fluorine-containing hydrocarbons contain at least one C-H bond as well as C-F bonds. In addition to these two essential types of bonds, the hydrocarbon also may contain other carbon-halogen bonds such as C-Cl bonds. … in one preferred embodiment, the hydrocarbon contains only carbon, hydrogen and fluorine. …Specific examples of the fluorine-containing hydrocarbons useful in the liquid compositions of the present invention, and their reported ozone depletion potentials are shown in the following Table I.
TABLE I
Compound
Designation Formula ODP*HCFC-22 CHClF2 0.05
HCFC-123 CHCl2CF3 <0.05
HCFC-141b CH3CCl2F <0.05
HFC-134a CH2FCF3 0__________
*Ozone depletion potential as reported in Process Engineering, pp 33-34, July, 1988.
Examples of other fluorine-containing hydrocarbons which may be useful in the liquid compositions of the present invention include trifluoromethane (HFC-23), 1,1,1,-trifluoroethane (HFC-143a), 1,1-difluoroethane (HFC-152a), 2-chloro-1,1,1,2-tetrafluoroethane (HCFC-124), 1-chloro-1,1,2,2-tetrafluoroethane (HCFC-124a), 1-chloro-1,1-difluoroethane (HCFC-142b), and 1,1,2,2-tetrafluoroethane (HFC-134). In the refrigerant art, the fluorohydrocarbons are often identified merely with the prefix 'R' in place of the above letters. For example HFC-23 is R-23, HCFC-124 is R-124, etc. … Mixtures of fluorine-containing hydrocarbons may be used, and the amount of each fluorocarbon in the mixture may be varied as desired. Examples of fluorohydrocarbon mixtures useful as (A) include: 142(b)/22; 134(a)/23; 22/124/152(a), etc."
The anticipation explicitly refers to single HFC's, and especially to R-134a. Mixtures of HFC's are mentioned towards the end of the above quote. The intellectual content of the disclosure includes mixtures of HFC's, thus including compositions of the present application.
The critical question is which mixtures are clearly disclosed, or form part of the technical information that the citation makes public. I do not believe that mixtures of any fluorocarbons should be regarded as clearly disclosed. I consider it is reasonable to regard the citation as clearly disclosing mixtures of those fluorocarbons that are themselves specifically disclosed, either as individual components or components of mixtures. [In the present case, that is those that are identified by their code number, e.g. R-22, R-23, etc.] R-32 and R-125 are not specifically referred to in the description. Consequently, it is unlikely that a reader would consider that they had been taught mixtures of HFC's including R-32 or R-125. On this basis I consider that the Lubrizol patent does not disclose a mixture including either R-32 or R-125.
Conclusion on novelty
Since component A must have at least one of R-32 or R-125, the Lubrizol patent does not disclose any compositions that would infringe the present application. The Lubrizol patent does not anticipate the present application.
It was conceded that other documents would have anticipated the present application if the priority date were deferred. As that is not the case, the other documents are not relevant to this opposition.
OBVIOUSNESS
Obviousness was argued on two different bases. First, it was submitted that there was no invention in the light of admissions of the common general knowledge in the specification itself. Second, it was submitted that there is no inventive step in the light of certain documents.
The relevant law
Section 7(2) provides a definition of inventive step for the purposes of the Patents Act.
"(2) For the purposes of this Act, an invention is to be taken to involve an inventive step when compared with the prior art base unless the invention would have been obvious to a person skilled in the relevant art in the light of the common general knowledge as it existed in the patent area before the priority date of the relevant claim, whether that knowledge is considered separately or together with either of the kinds of information mentioned in subsection (3), each of which must be considered separately.
(3) For the purposes of subsection (2), the kinds of information are:(a)prior art information made publicly available in a single document or through doing a single act; and
(b)prior art information made publicly available in 2 or more related documents, or through doing 2 or more related acts, if the relationship between the documents or acts is such that a person skilled in the relevant art in the patent area would treat them as a single source of that information;
being information that the skilled person mentioned in subsection (2) could, before the priority date of the relevant claim, be reasonably expected to have ascertained, understood and regarded as relevant to work in the relevant art in the patent area."
[The prior art base is defined in Schedule 1 of the Act.]
It is clear that inventive step is a matter that is presumed, unless it is demonstrated that the invention is obvious. The assessment of obviousness can be made against the common general knowledge alone, or the common general knowledge together with a document (or act) of the type covered by section 7(3). Section 7(3) documents must satisfy several requirements: the document must be publicly available inside or outside Australia (see the definition of "prior art base"); and the document would have reasonably been expected to have been ascertained, understood and regarded as relevant.
The normal approach to obviousness is the problem-solution approach: for instance, see Rhone-Poulenc Rorer S.A.'s Application [1995] APO 50. I note in passing that the problem-solution concept is evident in judicial decisions such as Minnesota Mining and Manufacturing Co v Beiersdorf (Australia) Ltd (1980) 144 CLR 253 (e.g. at 298: "this solution to the known problem") and Winner v Ammar Holdings Pty Ltd (1993) 113 ALR 63 (e.g. at 67: "The problem and the solution were readily apparent"). Once the problem has been formulated, and the common general knowledge or prior art base has been determined, the question of whether the claimed solution is obvious must be addressed. The test for obviousness is whether it would have been a matter of routine to proceed to the claimed invention.
"It is still correct to say that a valid patent may be obtained for something stumbled upon by accident, remembered from a dream or imported from abroad, if it otherwise satisfies the requirements of the legislation. What is important is that the patent itself should involve an inventive step, whether or not it was consciously taken by the patentee and whether or not it appeared obvious to the patentee himself. The test is whether the hypothetical addressee faced with the same problem would have taken as a matter of routine whatever steps might have led from the prior art to the invention, whether they be the steps of the inventor or not."
[Wellcome Foundation Ltd v V.R. Laboratories (Aust.) Pty Ltd (1981) 148 CLR 262 286]
The question of what would be routine can be considered using the "obvious to try" approach. This approach is well explained in Beecham Group Ltd's (Amoxycillin) Application [1980] RPC 261 (which has been approved in Coopers Animal Health Australia Ltd v Western Stock Distributors Ltd (1986) 67 ALR 390 at 410 and W R Grace & Co v Asahi Kasei Kogyo Kabushiki Kaisha (1993) 25 IPR 481 at 492 - 494) at 290 - 291:
"It is clearly established that, for a particular step or process to be obvious for the purpose of either section, it is not necessary to establish that its success is clearly predictable. It will suffice if it is shown that it would appear to anyone skilled in the art but lacking in inventive capacity that to try the step or process would be worthwhile. Worthwhile to what end? It must, in my opinion, be shown to be worth trying in order to solve some recognised problem or meet some recognised need."
[citations omitted]
This approach suggests that an invention is obvious if it would have been considered well worth trying, with the likelihood of success being sufficient to warrant the actual trial. However, it must always be remembered that there is an unclear line between normal trial and error and an inventive step:
"However, the test of whether something was 'worth trying' involves questions of degree … If the expectation of success is sufficiently predictable, and the effort involved is not going to be very great, it may well be that there is no inventive step. On the other hand, if the expectation of ultimate success is doubtful and the effort involved is great, the person undertaking the work should be entitled to a monopoly. A patent monopoly is awarded, not to reward genius but to encourage the disclosure of information which is of value to the public in that it takes the store of knowledge ahead by the requisite 'inventive step'."
[ICI Chemicals & Polymers Ltd v Lubrizol Corp Inc [1999] FCA 345 at [115], citations omitted]
What was the problem
In the Rhone-Poulenc decision I decided that the problem can be formulated from a reading of the specification in the light of surrounding facts (see also my recent decision in Emory University v Biochem Pharma Inc [1999] APO 50). The present specification lies in the field of CFC free heat transfer compositions. The specification makes it clear that HCFC's (which had been promoted as an alternative for CFC's) are not a long term solution to the problem of CFC's:
"However, such chlorine containing fluoroalkanes have been implicated in the destruction of the ozone layer and as a result the use and production thereof is to be severely limited by international agreement."
[page 1A, lines 28 - 32]
From the words of the specification itself, I consider that it is reasonable to formulate the problem as a desire to find a heat transfer composition that does not utilise CFC's or HCFC's.
What was the common general knowledge
Common general knowledge was defined by Aickin J in Minnesota Mining and Manufacturing Co v Beiersdorf (Australia) Ltd (1980) 144 CLR 253 at 292:
"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"
Mr Gleeson sought to rely on admissions in the specification as statements of common general knowledge. All parts of a document must be construed in context to determine their meaning, and the same is true of admissions (note Sumitomo Chemical Co Ltd v Rhone-Poulenc Chimie (1994) 30 IPR591 at 601 - 602).
Mr Gleeson asserted that a number of matters were common general knowledge.
a)CFC's, HCFC's and HFC's were known, and their refrigeration properties were known
b)CFC's, HCFC's and blends were useful in commercial refrigeration
c)the boiling points of the refrigerants were known
d)HCFC's were a short term replacement for CFC's, and HFC's were a long term alternative
e)R-134a was a useful replacement for R-12
f)mineral oils were not sufficiently miscible with R-134a to work satisfactorily
g)replacement lubricants for R-134a were being investigated from the classes of synthetic lubricants including PAG's and polyol esters
h)polyol esters were commercially available from ICI
i)R-134a was not a suitable replacement for R-22 in low temperature applications because of its boiling point
j)R-125 has been identified as a possibility for low temperature application
k)blends of R-134a, R-32 and R-125 were known, if not common general knowledge
l)ester lubricants were known
I will only consider whether these elements are common general knowledge as they are necessary below.
Is the invention obvious in the light of the common general knowledge alone
Assuming all of the above matters are common general knowledge, the use of HFC's as refrigerants would have been obvious to try. R-134a appears to have been a routine choice. The motivation to look beyond R-134a was suggested to be the fact that it was unsuitable for low temperature applications. However, low temperature applications are not part of the problem. Consequently, although blends may have been known, there was no motivation to go beyond R-134a. The claimed solution was not the obvious answer to the problem.
What documents are part of the prior art base
Mr Gleeson argued obviousness in the light of the following documents:
i)AU 54480/90 (the Lubrizol patent referred to earlier)
ii)EP 406479
iii)EP 415778
iv)AU 71419/91
v)AU 56198/90
vi)AU 56197/90
vii)AU 74076/91
viii)AU 91433/91
ix)EP 448402
All of the citations relate to heat transfer compositions. Document viii) was published on 22 July 1992. This is after the priority date of the present application. Consequently this document is not relevant to the ground of obviousness. Document ix) was published in Europe a short time (11 days) before the priority date of the present claims. The question that this raises is whether such a document would have reasonably been expected to be ascertained by a skilled person. While the onus of establishing that a document would have been ascertained is upon the opponents, there are reasonable presumptions that should apply. In the case of section 7(3) the relevant art is that in Australia, and the skilled person should be presumed to be working in Australia. It seems to me that if a document is published in Australia, it is prima facie reasonable to expect it to have been ascertained. On the other hand, when a document is not available in Australia, it is inherently unreasonable to expect the document to have been ascertained. Both presumptions are open to rebuttal. In the present case, it is not reasonable to expect that the skilled worker in Australia would have ascertained the document EP 448402. Consequently this document is not relevant to the ground of obviousness. Document vii) was published on 10 October 1991. This is one day before the priority date of the present application. Based on what I have said above, it is reasonable to expect that this document would have been ascertained.
Consequently documents viii) and ix) are not prior art for the purposes of section 7(3).
Is the invention obvious in the light of the prior art base documents
The essence of Mr Gleeson's submission was that the invention claimed in the present application amounts to a mere verification that a known set of lubricants can be used with a known refrigerant mixture.
The main document argued was the Lubrizol patent. As already discussed under novelty, this document discloses heat transfer compositions made of lubricants that are the same as that in the present case, and refrigerants that are different. It was argued that the present case merely represents the extrapolation of the Lubrizol lubricants to other refrigerants. The Lubrizol patent does not mention R-32 or R-125, so the extrapolation to refrigerants containing these HFC's is not suggested by that document. Instead, the motivation to try mixtures containing R-32 or R-125 must come from the common general knowledge. Item k) of the asserted common general knowledge is that blends of R-134a, R-32 and R-125 were known, if not common general knowledge. As this is the key element of common general knowledge for this ground, I will now consider whether it is common general knowledge.
a) The priority document GB 9121657 states at page 2, lines 3 to 6:
"It has thus been proposed that these other refrigerants are replaced by refrigerant mixtures, in particular binary mixtures of refrigerants, such as R-134a and difluoromethane (R-32) or pentafluoroethane (R-125) and R-32."
This does not suggest that the mixtures were widely known enough to be considered as common general knowledge.
b)The refrigerant mixtures are referred to in the documents i), iv), v), vi), vii), viii) and ix). On its own, the fact that the matter is included in patents is not sufficient to establish that the information has become widely known enough to be considered as common general knowledge.
I conclude that it has not been established that the refrigerant mixtures were common general knowledge, and consequently obviousness in the light of the Lubrizol patent is not made out.
It was then argued that the invention is obvious in the light of the other documents as follows. Documents ii) and iii) disclose polyol esters that are useful lubricants with at least a single HFC. Mr Gleeson's argument was that the refrigerant mixtures of the present application were common general knowledge, making the combination a mere analogous use. The relevant knowledge in this case is again item k), which I consider has not been shown to be common general knowledge (see above). Consequently this attack on obviousness fails.
The next argument was that documents iv), v), vi) and vii) disclose mixtures of HFC's, and the lubricants of the present application were common general knowledge. Document iv) discloses binary blends of R-134 with either R-134a or R-125, with a polyalkylene glycol lubricant. Document v) discloses R-134, R-134a or R-125 (or blends thereof) combined with a polyalkylene glycol lubricant. Document vi) also discloses R-134, R-134a or R-125 (or blends thereof) combined with a polyalkylene glycol lubricant. Document vii) discloses ternary blends, including R-32/125/134a (see Fig 3), but does not refer to lubricants. None of the documents suggest the use of ester lubricants.
It seems that the citations teach a solution to the problem that does not use ester lubricants, and it is not apparent why a person would seek to vary the compositions disclosed by the citations. This is probably enough to dispose of the question of obviousness. However, assuming that it would have been a matter of routine to look beyond the citations, I will consider whether it would have been a matter of routine to use ester lubricants. The declarants Dobney and Harrington make some reference to the use of ester lubricants:
"In addition, prior to the priority date, if I had been provided with the mixture of hydrofluoroalkanes claimed in claim 1 of the opposed patent application, namely R-32, R-134a and R-125, and asked to suggest a suitable lubricant, I would have considered it obvious to try a lubricant which was known to be suitable for use with R-134a and for mixtures of other HFCs is referred to in AU-A-54480/90. Examples of lubricants which were known to be suitable for use with R-134a prior to the priority date include Emkarate® RL-212 and Emkarate® RL-184 which are described on page 23 of the opposed patent application as commercially available ester-based lubricants for use with R-134a"
[Harrington declaration in support, para 31]"I believe that all the applicants have done is to take an ester lubricant which was known to be suitable for use with R-134a, test it with mixtures of fluoroalkanes containing a significant proportion of R-134a and determine that it is suitable. That known ester lubricant is set out in Australian Patent Application No 54480/90 (to which I will refer later) in which the same formula to describe the lubricants is used. In addition, the opposed patent application admits that commercially available ester-based lubricants for use with R-134a were used and found to be suitable."
[Dobney declaration in support, para 19]
I am satisfied that ester lubricants were known, and commercially available. It is not clear whether they had become part of the common general knowledge (particularly with regard to their suitability for use with R-134a), and thus it is uncertain whether their use could have been a matter of routine. I am not satisfied that it would have been obvious to replace the polyalkylene glycol lubricant with an ester.
Conclusion on obviousness
The invention as claimed is not obvious, either in the light of the common general knowledge alone or any of the citations.
MANNER OF MANUFACTURE
Mr Gleeson submitted that the invention is not a manner of manufacture for the reasons given in the statement of grounds and particulars. This statement says:
"Polyol esters derived from compounds such as pentaerythritol, dipentaerythritol, tripentaerythritol, trimethylolpropane and neopentylglycol were known at the priority date to have lubricant properties which made them useful as lubricants in fluid compositions for use in compression refrigeration which comprise fluorohydrocarbons. Accordingly the use of known polyol esters to provide lubrication in known compositions for the reason that the esters possessed known properties which rendered them useful for that purpose renders the alleged invention not a manner of manufacture.
It is admitted in the Opposed Application at pages 23-24 that "EMKARATE"™ RL-212 and "EMKARATE"™ RL-184 were commercially available ester based lubricants for use with R-134a. The use of known commercially available ester based lubricants with mixtures of fluorohydrocarbons utilising known properties of those lubricants is a mere new use of an old contrivance and is therefore not a manner of manufacture."
This was argued as a matter on the face of the specification, and as a mere collocation.
The relevant law
The High Court in NV Philips Gloeilampenfabrieken v Mirabella International Ltd (1995) 183 CLR 655 stated that manner of manufacture is a threshold question, which is assessed by reference to traditional principles. For instance:
"if it is apparent on the face of the specification that the quality of inventiveness necessary for there to be a proper subject of letters patent under the Statute of Monopolies is absent, one need go no further"
[page 664]"the preferable conclusion is that the phrase 'manner of manufacture within the meaning of section 6 of the Statute of Monopolies' in s 18(1)(a) should be understood as referring to a process which is a proper subject matter of letters patent according to traditional principle"
[page 667]
It is clear that this determination is made "on the face of the specification", without consideration of the prior art. Mr Gleeson also submitted that the present case can be compared to that in Commissioner of Patents v Microcell Ltd (1959) 102 CLR 232. The principle in Microcell is summarised in the headnote as:
"It is not an inventive idea for which a monopoly can be claimed to take a substance which is known and used for the making of various articles and make out of it an article for which its known properties make it suitable, although it has not in fact been used to make that article before."
There was some discussion of the appropriate date for assessing whether the invention is a manner of manufacture. Under section 59(b), the ground of opposition is:
"that the invention is not a patentable invention because it does not comply with paragraph 18(1)(a) or (b)"
Clearly the question for me is whether the invention "is not" a patentable invention. This implies that the relevant date is the date at which I am deciding the issue.
Is there a manner of manufacture?
On the face of the specification before me, it deals with compositions that are useful as an ozone friendly heat transfer composition. While the refrigerants and lubricants used are known compounds, it is apparent on the face of the specification that these compositions are asserted to have an advantage over previous compositions. In my opinion, this is sufficient for there to be an invention on the face of the specification.
Turning to the issue of a collocation, it is apparent that miscibility of lubricants and refrigerants is an important issue in this art. The known properties of lubricants and refrigerants do not seem to have made it apparent that a miscible collocation would be achieved. Consequently, achieving the miscible end result is something more than the known properties of the refrigerants and lubricants. The invention is not a mere collocation.
CONCLUSION
The oppositions are unsuccessful on all grounds. Subject to any appeal, I direct that the application proceed to sealing.
COSTS
The opponents have been unsuccessful on all grounds, so I consider it appropriate to award costs against them. I can see no reasons to vary the costs from the full amount specified in the Schedule.
I award costs according to Schedule 8 against each of the opponents.
Dr S.D.Barker
Delegate of the Commissioner of Patents
Patent attorneys for the applicant : Phillips Ormonde & Fitzpatrick, Melbourne
Patent attorneys for the opponents : Callinan Lawrie, Melbourne
ANNEX 1: DESIGNATIONS OF REFRIGERANT FLUIDS
| Designation | Type | Chemical Name | Chemical Formula |
| R-11 | CFC | Trichlorofluoromethane | CCl3F |
| R-12 | CFC | Dichlorodifluoromethane | CCl2F2 |
| R-13 | CFC | Chlorotrifluoromethane | CClF3 |
| R-22 | HCFC | Chlorodifluoromethane | CHClF2 |
| R-23 | HFC | Trifluoromethane | CHF3 |
| R-32 | HFC | Difluoromethane | CH2F2 |
| R-113 | CFC | 1,1,2-Trichlorotrifluoroethane | CCl2FCClF2 |
| R-114 | CFC | 1,2-Dichlorotetrafluoroethane | CClF2CClF2 |
| R-115 | CFC | Chloropentafluoroethane | CClF2CF3 |
| R-123 | HCFC | 1,1-Dichloro-2,2,2-trifluoroethane | CHCl2CF3 |
| R-125 | HFC | Pentafluoroethane | CHF2CF3 |
| R-134 | HFC | 1,1,2,2-Tetrafluoroethane | CHF2CHF2 |
| R-134a | HFC | 1,1,1,2-Tetrafluoroethane | CH2FCF3 |
| R-141b | HCFC | 1,1-Dichloro-1-fluoroethane | CCl2FCH3 |
| R-142b | HCFC | 1-Chloro-1,1-difluoroethane | CClF2CH3 |
| R-143 | HFC | 1,1,2-Trifluoroethane | CHF2CH2F |
| R-143a | HFC | 1,1,1-Trifluoroethane | CF3CH3 |
| R-152a | HFC | 1,1-Difluoroethane | CHF2CH3 |
| R-227ca | HFC | 1,1,1,2,2,3,3-Heptafluoropropane | CF3CF2CF2H |
| R-227ea | HFC | 1,1,1,2,3,3,3-Heptafluoropropane | CF3CHFCF3 |
| R-245ca | HFC | 1,1,2,2,3-Pentafluoropropane | CHF2CF2CFH2 |
| R-500 | CFC/HFC | R-12/152a (73.8/26.2 wt %) | |
| R-501 | HCFC/CFC | R-22/12 (75/25 wt %) | |
| R-502 | HCFC/CFC | R-22/115 (48.8/51.2 wt %) |
ANNEX 2: THE CLAIMS OF 658005
A working fluid composition comprising:
(A) a heat transfer fluid comprising a mixture of at least two hydrofluoroalkanes selected from the group consisting of difluoromethane, 1,1,1,2-tetrafluoroethane and pentafluoroethane; and
(B) a lubricant which is at least partially soluble in each component of the heat transfer fluid said lubricant comprising one or more compounds of general formula:R(O-C(=O)-R1)n II
wherein
R is the hydrocarbon radical remaining after removing the hydroxyl groups from pentaerythritol, tripentaerythritol, trimethylol ethane, trimethylol propane or neopentyl glycol, or the hydroxyl containing hydrocarbon radical remaining after removing a proportion of the hydroxyl groups from pentaerythritol, dipentaerythritol, tripentaerythritol, trimethylol ethane, trimethylol propane or neopentyl glycol;
each R1 is, independently, H, a straight chain (linear) aliphatic hydrocarbyl group, a branched aliphatic hydrocarbyl group, or an aliphatic hydrocarbyl group (linear or branched) containing a carboxylic acid or carboxylic acid ester substituent, provided that at least one R1 group is a linear aliphatic hydrocarbyl group or a branched aliphatic hydrocarbyl group; and
n is an integer.
A working fluid composition as claimed in claim 1 wherein the heat transfer fluid (A) is a binary mixture consisting substantially of 1,1,1,2-tetrafluoroethane and difluoromethane.
A working fluid composition as claimed in claim 1 wherein the heat transfer fluid (A) comprises a mixture of:
difluoromethane; and
pentafluoroethane.
A working fluid composition as claimed in claim 1 wherein the heat transfer fluid (A) comprises a mixture of:
1,1,1,2-tetrafluoroethane;
difluoromethane; and
pentafluoroethane.
A working fluid composition as claimed in any one of claims 1 to 4 wherein the linear and branched hydrocarbyl groups specified for R1 are unsubstituted and the carboxylic acid or carboxylic acid ester containing hydrocarbyl group specified for R1 contains no other substituents.
A working fluid composition as claimed in any one of claims 1 to 5 wherein the lubricant (B) comprises one or more compounds of Formula II in which R is the hydrocarbon radical remaining after removing the hydroxyl groups from pentaerythritol, dipentaerythritol, tripentaerythritol, trimethylol ethane, trimethylol propane or neopentyl glycol.
A working fluid composition as claimed in claim 6 wherein the lubricant (B) comprises one or more compounds of Formula II in which R is the hydrocarbon radical remaining after removing the hydroxyl groups from pentaerythritol, dipentaerythritol, trimethylol propane or neopentyl glycol.
A working fluid composition as claimed in claim 7 wherein the lubricant (B) comprises one or more compounds of formula II in which R is the hydrocarbon radical remaining after the hydroxyl groups from pentaerythritol, dipentaerythritol or trimethylol propane.
A working fluid composition as claimed in any one of claims 1 to 8 wherein the lubricant (B) comprises one or more compounds of Formula II in which each R1 is, independently, a linear alkyl group or a branched alkyl group.
A working fluid composition as claimed in claim 9 wherein at least one R1 group is a linear alkyl group.
A working fluid composition as claimed in claim 9 or claim 10 wherein at least one R1 group is a linear alkyl group and at least one R1 group is a branched alkyl group.
A working fluid composition as claimed in any one of claims 1 to 4 wherein the lubricant (B) comprises one or more esters of general formula:
R2(O-C(=O)-R3)p III
wherein
R2 is the hydrocarbon radical remaining after removing the hydroxyl groups from pentaerythritol, dipentaerythritol or trimethylol propane;
each R3 is, independently, a linear alkyl group or a branched alkyl group; and
p is an integer of 3, 4 or 6,
wherein one of more of the named polyols, one or more linear alkanoic acids, or esterifiable derivatives thereof, and optionally one or more branched alkanoic acids, or esterifiable derivatives thereof, are utilised in the synthesis of the ester.
A working fluid composition as claimed in claim 12 wherein a mixture of one or more linear alkanoic acids, or esterifiable derivatives thereof, and one or more branched alkanoic acids, or esterifiable derivatives thereof, are utilised in the synthesis of the ester.
A working fluid composition as claimed in claim 12 or claim 13 wherein the lubricant comprises one or more compounds of Formula III in which R2 is the hydrocarbon radical remaining after removing the hydroxyl groups from pentaerythritol or dipentaerythritol.
A heat transfer device containing the working fluid composition claimed in any one of claims 1 to 14.
A working fluid composition as claimed in claim 1 substantially as hereinbefore described with reference to any one of the examples.
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