SNF (Australia) Pty Ltd v Ciba Specialty Chemicals Water Treatments Limited [2012] FCAFC 95 (29 June 2012)

In a majority decision, the Full Federal Court has affirmed the decision of Justice Kenny at first instance, finding five innovation patents owned by Ciba Specialty Chemicals Water Treatments Limited to be valid. SNF (Australia) Pty Ltd, the appellant and accused infringer, had sought to overturn the primary judge's findings on validity but did not challenge the infringement findings.

The issues raised by SNF and Ciba on appeal

SNF appealed the first instance decision primarily on the basis that the primary judge had incorrectly applied legal principles of claim construction, and had given undue weight to evidence from an expert who was not suitably qualified to comment on how particular terms in the claims would be interpreted by a skilled addressee of the patents.

The appeal turned almost entirely on the interpretation of the term "rigidification" (as it applied to the state of a slurry containing tailings) in the context of the patents. SNF contended that, if its interpretation was adopted, the claims lacked novelty or an innovative step in view of one of a number of pieces of prior art information including prior publications and prior public uses at various mining sites. Ciba's contention, in line with the evidence of its expert, was that the term "rigidification" implied the presence of a networked or chemically bonded structure, thereby distinguishing it from settling or sedimentation processes disclosed by the prior art.

The Court's conclusions on interpretation of the claims

The Court's decision was made with reference to one of the innovation patents, in which the claims were directed specifically to use of the process in rigidifying coal tailings. The parties had agreed that this patent was representative of the patents as a whole for the purposes of settling the issues.

On the issue of construction, neither Justice Bennett (with whom Justice Finn agreed) nor Justice Dowsett found the expert evidence regarding the meaning of rigidification to be of assistance. Accordingly, construction of the claims was carried out purely with reference to the content of the patent specification.

Justice Bennett considered the meaning of "rigidification" in the context of the problems addressed by the invention, including improving on the prior art processes described in the specification. In that context, Her Honour found, the specification referred to advantageous results achieved by the claimed process by particular means, namely the use of "an effective rigidifying amount" of aqueous solution of a water-soluble polymer. This was to be contrasted with the "natural" rigidification process brought about by settling and sedimentation, which in her Honour's view did not fall within the meaning of "rigidification" in the sense meant by the patents. Notably, interpretation of the claims did not depend on the concept of a networked structure or the evidence in relation to it.

In a dissenting judgment, Justice Dowsett came to a different conclusion regarding the meaning of "rigidification". His Honour considered the use of the term throughout the specification and rejected Ciba's contention that the term had a special meaning which implied the presence of a networked structure, finding that nothing in the specification provided any reason for departing from the usual meaning of the word. In particular, the specification did not disclose the presence of any networking or chemical bonding effect within the slurry. "A process of improving rigidification" was held to mean "a process which develops yield strength", and thus to encompass settling and sedimentation processes of the prior art.

Validity depended on the claim interpretation adopted

The claims were novel over the prior art relating to settling and sedimentation

The claim interpretation adopted by Justices Bennett and Finn, in the majority, was determinative of novelty and innovative step. On the basis that "rigidification" was distinct from settling and sedimentation, it followed that the claimed process was distinguished over the majority of the prior art relied upon by SNF. It was apparent from the evidence at trial that this distinction made a substantial contribution to the working of the invention, and the majority therefore upheld the primary judge's finding that the claims involved an innovative step.

Had SNF's (and Justice Dowsett's) interpretation of "rigidification" been adopted, the claims would have lacked novelty in view of one of a number of pieces of prior art and it would have been unnecessary to consider the issue of innovative step.

Did the prior art disclose aqueous solutions of water-soluble polymers?

A further issue on appeal was whether two of the prior art documents disclosed use of a flocculant in the form of an aqueous solution of a water-soluble polymer.

The majority held that the first document disclosed, in isolation, an aqueous solution of a water-soluble polymer. Importantly, however, it did not disclose that feature in combination with all the other features of the claimed process, and so did not deprive claim 1 of novelty.

With regard to the second document, it was agreed that although it may have disclosed an aqueous solution of a water-soluble polymer, this was not in the context of its use in a process of the type claimed in the patents. The Court therefore found that the claims were novel in view of the second document.

Given that neither document disclosed a process in which an aqueous solution of a water-soluble polymer was used as a flocculant, and that the evidence showed that this made a substantial contribution to the working of the invention, the majority held that the claims involved an innovative step.

Lessons for patent owners

Importance of statements in the patent specification

In Australian patent litigation, expert evidence typically plays an important role in assisting the Court to interpret the claims and to ascertain common general knowledge. This was certainly the case in the first instance decision. However, on appeal, it is apparent that none of the judges considered the evidence as it related to claim interpretation to be particularly helpful. As a result it was the wording of the specification itself which was critical in determining the outcome. In particular, the specification included statements in the summary of the invention section which explained the effects of certain features of the claims. These statements proved to be persuasive, in the eyes of the Court, in distinguishing the claims over the prior art.

The decision provides an important reminder that the claims are interpreted in the light of the specification as a whole, and that the importance of features recited in the claims should be discussed in the body of the specification whenever possible and appropriate.