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Sudarshan Chemical Industries Ltd v Clariant Produkte (Deutschland) GmbH [2013] EWCA Civ 919

Case Summary  |  Judgment  |  30 July 2013


Martin Howe QC and Henry Ward appeared in the Court of Appeal for Sudarshan, successfully resisting an appeal by Clariant from the Patents Court decision [2012] EWHC 1569 (Ch).

The case concerned a pigment and its crystal forms. Clariant owned patents in Europe and elsewhere (the “First Patents”) which disclosed the new pigment and a process for its manufacture. Once the First Patents expired, Sudarshan began to sell its own pigment made in accordance with the teaching of Clariant’s First Patents. However, Clariant had obtained a subsequent patent (the “Second Patent”) for a particular crystal form (polymorph) of the pigment. Clariant alleged that Sudarshan’s product infringed the Second Patent and wrote a letter threatening to sue Sudarshan and its customers for infringement.

At first instance, Sudarshan successfully ran a “Gillette” defence in that they had simply implemented the prior art with obvious and route variations; and hence the claims of the Second Patent must be invalid if and to the extent that they covered the Sudarshan product. All the product claims of the Second Patent were held to be obvious in any event. Giving the leading judgment in the Court of Appeal, Kitchin LJ held that there was ample evidence before the trial Judge (John Baldwin QC sitting as a deputy judge of the Patents Court) for him to have come to these conclusions. The Court of Appeal also held after reviewing the authorities both since and before the 1977 Act, that the threat made by Clariant to sue Sudarshan’s customers, even where those threats had not been communicated to the customers, was actionable under s.70 of the Patents Act 1977.