Ambiguity in specific definition of claim terms

Tsuyoshi Nakamura | October 25, 2017

ORGANIK KIMYA AS, v. ROHM AND HAAS COMPANY

October 11, 2017

Before Prost, Newman, and Taranto. Opinion by Newman.

Summary:

In the inter partes review (“IPR”) proceedings, the Patent Trial and Appeal Board (“PTAB”) made claim interpretation about claimed “swelling agent” by relying on patentee’s specific definition provided in the specification and decided that the alleged prior arts fail to disclose such “swelling agent.”  Appellant, Organik Kimya AS argues that the specific definition includes ambiguity due to open-ended definition and the claims cannot be reasonably interpreted to exclude those prior arts.  The court affirmed the decision of PTAB.  The specification contained many definitions of technical terms.  Careful wording would be more desired in drafting functional definition for claim terms, which provides specific meaning different from ordinary and customary one.

当事者系レビュー(IPR)のクレーム解釈において、審判部は、用語”swelling agent”について明細書に記載された特別な定義に基づいてその意味を確定し、そのような限定は先行技術に開示がないと判断した。IPR申請者側は、明細書の定義はオープンであって先行技術も含むように解釈されるべきとして争った。CAFCは特許権者に有利な判断を下した。本件特許の明細書には多くの用語に関する定義が含まれており、争点となった定義は機能的な特徴をもって用語を広く定義しようと試みたものである。機能的な定義は外縁が不明確になりがち故、特に留意が必要となる。機能的な定義を構成要件とした従属項を追加しておくという方法も考えられる。

Details:

The patent at issue (U.S Patent No. 6,020,435 (“the ’435 Patent”)) relates to aqueous emulsion polymerization processes for preparing polymer emulsions and emulsion polymers formed therefrom to overcome the deficiencies in the previously known processes by providing low density voided emulsion polymers and a process for preparing them.  Especially, the ’435 patent describes the features: “we have discovered that by providing an aqueous emulsion of the multi-stage emulsion polymer, monomer and swelling agent under conditions wherein there is no substantial polymerization of the monomer, we can enhance the extent of swelling of the multistage emulsion polymer.” Representative claim 1 is as follows:

  1.  A process for preparing emulsion polymer particles comprising:

 (a) providing an aqueous emulsion of

(i) multi-stage emulsion polymer, comprising a core stage polymer and a shell stage polymer,
wherein the core stage polymer comprises, as polymerized units, from 5 to 100 percent by weight, based on the weight of the core stage polymer, of hydrophilic monoethylenically unsaturated monomer, and from 0 to 95 percent by weight, based on the weight of the core stage polymer, of at least one nonionic monoethylenically unsaturated monomer; and wherein the shell stage polymer comprises, as polymerized units, at least 50 percent by weight of nonionic monoethylenically unsaturated monomer;

(ii) monomer at a level of at least 0.5 percent by weight based on the weight of the multi-stage emulsion polymer; and

(iii) swelling agent under conditions wherein there is no substantial polymerization of the monomer; and

(b) reducing the level of monomer by at least fifty percent.

The key issue in the present case is the interpretation of the claimed “swelling agent” which is a part of the aqueous emulsion.  Patentee alleged and the PTAB accepted specific definition which was different from ordinary and customary meaning of claim term by relying on legal precedent, for example, “claim term will not receive its ordinary meaning if the patentee acted as his own lexicographer and clearly set forth a definition of the disputed claim term in either the specification or prosecution history.” CCS Fitness, Inc. v. Brunswick Corp., 288 F.3d 1359, 1366 (Fed. Cir. 2002).

Patentee alleged that that a person of ordinary skill in the art would understand from the Specification that the term “swelling agent” means

an ingredient that is capable of permeating the shell and swelling the core of the multi-stage emulsion polymer (ingredient (i) of step (a)) in the presence of the swelling monomer (ingredient (ii) of step (a)) under conditions of no substantial polymerization, in the process in which the ingredient in question is being employed as a “swelling agent.”

The PTAB interpreted the claimed “swelling agent” as:

expressing a structural element, i.e., “an aqueous or gaseous, volatile or fixed base, or combinations thereof,” in functional terms, i.e., “capable of permeating the shell and swelling the core, in the presence of the multistage polymer and monomer, under the conditions of the specific process for which the agent is to be used.”

In making this interpretation, the PTAB relied on the several descriptions of the specification:

Suitable swelling agents include, are those which, in the presence of the multistage emulsion polymer and monomer, are capable of permeating the shell and swelling the core. Swelling agents may be aqueous or gaseous, volatile or fixed bases or combinations thereof.

Suitable swelling agents include volatile bases such as ammonia, ammonium hydroxide, and volatile lower aliphatic amines, such as morpholine, trimethylamine, and triethylamine, and the like; fixed or permanent bases such as potassium hydroxide, lithium hydroxide, zinc ammonium complex, copper ammonium complex, silver ammonium complex, strontium hydroxide, barium hydroxide and the like.

The core polymer of the multistage emulsion polymer swells when the core is subjected to a basic swelling agent that permeates the shell to at least partially neutralize the hydrophilic-functionality of the core, preferably to a pH of at least about 6 to at least about 10, and thereby result in swelling by hydration of the hydrophilic core polymer.

(emphasis added)

In this appeal, Appellant, Organik Kimya AS, challenged the ambiguity contained in the definition of the specification.  More specifically, Appellant alleged that the specification provides an open-ended definition of “swelling agent” by using the word “include” in the definition, and thus, the PTAB improperly adopted the narrower of two possible constructions caused by a “grammatically ambiguous passage.”  The paragraph at issue is as follows:

Suitable swelling agents include, are those which, in the presence of the multistage emulsion polymer and monomer, are capable of permeating the shell and swelling the core. Swelling agents may be aqueous or gaseous, volatile or fixed bases or combinations thereof.

Appellant alleged that “the word ‘include’ opens the definition of ‘swelling agent’ to include bases that do not act by penetrating the shell, that are not used under the conditions described in the specification, and that have not been shown to achieve swelling.”  According to such broader interpretation, the ’435 Patent claims should have been anticipated.

The PTAB took a position and the court agreed that “the [s]pecification’s use of the word ‘include,’ in this instance, is modified by the phrase immediately following it, i.e., ‘are those which,’ suggesting that suitable swelling agents include only those which exhibit the functional characteristic thereafter described.” (emphasis added)

The PTAB further described its basis that, “[i]n contrast, the following paragraph of the Specification describes the structural requirement for suitable swelling agents using the word ‘include,’ without modifying it with a restrictive phrase. Instead, when disclosing the volatile, fixed and permanent bases, the word ‘include’ is coupled with the phrases ‘such as’ and ‘and the like.’” (emphasis added)

Take away:

 Functional definition, in its nature, may give broader meanings to structural terms.  But, it may cause ambiguity problem at the same time.  Careful wording would be more desired in drafting functional definition for claim terms, which provides specific meaning different from ordinary and customary one.  Including an additional dependent claim which defines such functional feature would be one option.

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