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UK – Anan Kasei & Rhodia Operations v. Neo Chemicals and Oxides

29 Oct 2019

Anan Kasei Co. Ltd & Rhodia Operations S.A.S. v Neo Chemicals and Oxides Limited & Neo Performance Materials Inc, Court of Appeal, London, 9 October 2019, [2019] EWCA Civ 1646

In this judgment, the Court of Appeal has dismissed an appeal by Neo Chemicals and Oxides (Europe) Limited (previously Molycorp Chemicals and Oxides (Europe) Limited) and Neo Performance Materials Inc (together “Neo”) relating to the sufficiency of European Patent (UK) No. 1 435 338 (the “Patent”) owned by Anan Kasei Co. Ltd (now Solvay Special Chem Japan, Ltd) and exclusively licensed to Rhodia Operations S.A.S. (together “Rhodia”).

In doing so, the Court of Appeal has provided further guidance on the law of sufficiency, in particular insufficiency due to ambiguity (or uncertainty), and excessive claim breadth. In the same judgment, the Court of Appeal allowed two procedural appeals by Rhodia regarding the joining of Neo’s parent company to the proceedings.


The Patent in suit related to the use of ceric oxide as a catalyst for purifying vehicle exhaust gases. Claim 1 of the Patent was to “A ceric oxide consisting essentially of a ceric oxide, and wherein said ceric oxide has a specific surface area of not smaller than 30.0 m2/g when subjected to calcination at 900oC for 5 hours” i.e. a class of products identified by their composition and physical characteristics following calcination.

The proceedings started with Rhodia bringing patent infringement proceedings against Neo. In response, Neo denied infringement and counterclaimed for revocation of the Patent on the basis of lack of novelty, obviousness and insufficiency (although the lack of novelty objection was dropped at trial). At first instance, Mr Roger Wyand QC (sitting as Deputy High Court Judge) found the Patent to be valid and infringed. Neo appealed the Judge’s rejection of two of its insufficiency attacks.

Attack 1: Insufficiency due to uncertainty

First, although the parties were agreed that the inclusion of the words “consisting essentially of” in Claim 1 meant that, apart from the mandatory ingredient (here, ceric oxide), no other ingredients are present which materially affect the essential characteristics of the product, Neo contended that the inclusion of this language rendered the claim invalid for insufficiency.

According to Neo, if an allegedly infringing ceric oxide contained an ingredient other than ceric oxide, the skilled person would be required to perform a test to determine whether the presence of the extra ingredient had a material effect on the essential characteristics of the product (the so-called “materiality test”). Neo argued that a purchaser of the alleged infringing sample would not be able to obtain the control sample needed to perform the materiality test nor determine the effect of the added ingredient, such a test therefore gave rise to uncertainty and imposed an undue burden.

Dismissing this insufficiency attack, Lord Justice Floyd considered the law on insufficiency due to ambiguity or, as he stated it should more accurately be referred to, uncertainty. He explained that provided the claim is conceptually certain, it will not be rendered insufficient merely because there is some doubt at the edge of a claim (a so-called fuzzy boundary). Given that the specification must disclose the invention clearly and completely enough for it to be performed by the skilled person, the question of whether or not a purchaser of the product would be able to determine infringement was simply not relevant. Further, on the evidence, Neo had not established that the materiality test did impose an undue burden on the skilled person.

Attack 2: Insufficiency due to excessive claim breadth

Secondly, Neo contended that Claim 1 of the Patent was excessively broad. Although Claim 1 disclosed a desirable class of products (being ceric oxide with required characteristics), the Patent only disclosed one method of making ceric oxide with those characteristics. On this basis, Neo argued, the scope of Claim 1 extended beyond Rhodia’s technical contribution to the art.

Although Lord Justice Floyd agreed that the specification only enables those structures that would be made by the skilled person using the methods disclosed in the specification together with their common general knowledge, it was necessary for Neo to have positively established that there were structures that were covered by the claim that could not be made using the method taught in the Patent. In the absence of any evidence, there was no reason for the Court to assume that Claim 1 extended to any such structures. Accordingly, Neo’s second insufficiency attack failed on the basis that it had not been made out on the evidence.

A copy of the decision can be read here.

Headnote by Olivia Henry and Rachel Mumby, Bristows LLP