The Lost Art of Patent Claim Drafting – Why Good Claim Drafting is Essential Under Australia’s Revised Patents Act

Dr. Jim Y. Onishi and Dr. Elizabeth E. Houlihan

We report the recent Patent Office Decision in Cytec Industries Inc. v Nalco Company [2018] APO 4, which dealt with interpreting the “Raising the Bar”-revised requirements of subsection 40(2)(a) of Australia’s Patents Act 1990 in relation to post acceptance claim amendments under subsection 102(2)(b).

Relevant Law

Subsection 102(2) states that:
An amendment of a complete Specification is not allowable after the relevant time if, as a result of the amendment:
(a) a claim of the Specification would not in substance fall within the scope of the claims of the Specification before amendment; or
(b) the Specification would not comply with subsection 40(2) or (3),

where the “relevant time” is after the Specification has been accepted.

Subsection 40(2) of the Patents Act 1990 states that:
A complete Specification must: (a) disclose the invention in a manner which is clear enough and complete enough for the invention to be performed by a person skilled in the relevant art.

This Australian Patent update will focus on the Patent Office’s consideration of whether, as a result of the proposed claim amendments filed by the patent applicant, the complete Specification disclosed the claimed invention clearly and completely enough to satisfy the requirement of subsection 40(2)(a) of the Patents Act 1990. It will also focus on whether a proper understanding of the invention and correct claim drafting could have saved the claim.


Cytec Industries Inc (“Cytec”, the Opponent) filed an Opposition against the acceptance of Nalco Company’s (“Nalco”, the Applicant) patent application, which was directed to reducing scale in a Bayer process. During the opposition proceedings, Nalco filed a request to amend Claim 1 to recite:

A method for the reduction of aluminosilicate containing scale in a Bayer process comprising the steps of:
adding to the Bayer process stream an aluminosilicate scale inhibiting amount of a composition comprising at least one small molecule,
wherein the small molecule is selected from the group consisting of compounds (I) through (XIII), (XV) through (XXX), (XXXII) through (LVIII) and (LX) through (LXVII):
[structures omitted].”

Prior to filing the amendment, Claim 1 recited a method for the reduction of aluminosilicate containing scale in a Bayer process comprising adding to the Bayer process stream an aluminosilicate scale inhibiting amount of a composition comprising at least one small molecule selected from a broad class of small molecules defined in a generic “Markush” format. Since all the small molecules specified in amended Claim 1 fell within the scope of the broad class defined in the accepted claim, subsection 102(2)(a) was satisfied.

Opposition to the Amendment

One of the grounds asserted by Cytec was that the compounds denoted by LXVI and LXVII, which were not specifically claimed previously, are not disclosed in the complete Specification in a clear enough and complete enough manner for the invention to be performed by a person skilled in the relevant art (“PSA”) as required by subsection 40(2)(a) of the Patents Act 1990.

The Delegate’s Observations

Did the Specification disclose the subject matter (i.e., the compounds denoted by LXVI and LXVII) now claimed as a result of the amendments, in a clear enough and complete enough manner to be performed by the person skilled in the art?

In answering this question, the Delegate followed the same process of reasoning applied in UK and EPO decisions for guidance. In so doing, the Delegate had to determine:
(i) the scope of the invention as claimed;
(ii) what the Specification disclosed to the PSA; and
(iii) whether the Specification provided an enabling disclosure of all the things falling within the scope of the claims.

The Delegate construed Claim 1 as being directed to reducing aluminosilicate scale in a Bayer process stream involving the step of adding to the process stream an amount of a composition. The use of the term “comprising” in relation to the step meant that additional steps, not explicitly defined in the claim, could be included within the method. The Delegate also considered that the composition to be added may optionally contain more than one of the components specified in the Claim. Accordingly, the composition to be added could include either of the compounds denoted by LXVI and LXVII, either in the presence or the absence of any other of the small molecules specified in the Claim.

The Delegate determined that the Specification referred to the small molecule as being a reaction product between an amine molecule and an amine-reactive molecule, or a mixture of such reaction products. Thus, it was considered that mixtures of scale inhibiting small molecules were clearly envisaged in the Specification.

The Delegate noted that there were no depictions of structures of compounds LXVI and LXVII; however, he concluded that these compounds were inherently disclosed in the Specification.

Notably, the Specification contained one Example teaching a general method of combining three components, designated A, G and E, to form mixtures of compounds of the invention. Importantly, the Specification only ever referred to isolating the “product mixture” and there was no disclosure or any worked examples demonstrating how each component of the mixture could be isolated.

Evidence submitted by the Opponent, Cytec, suggested that the product mixtures obtained by following the example would in fact be a complex mixture of many compounds, the actual composition of which would vary according to numerous factors. The Delegate considered that it was plausible that the reactions disclosed in the Specification produced mixtures containing compound LXVI or LXVII. However, it was clear that these compounds could only be produced as part of a complex mixture involving at least 15 possible compounds being formed from reagents having several reactive functional moieties.

Accordingly, the Delegate considered that the Specification enabled the production of compound mixtures.

In relation to the question of whether each of these compounds on its own, as claimed, could be produced, the Delegate then considered whether each compound could be produced without undue burden.

The applicant, Nalco, made submissions to the effect that the PSA would not expect chemical additives for use in the Bayer process to be 100% pure compounds and that it was commonplace to use chemical structures to denote industrial grade mixtures of chemical compounds. Therefore, their isolation is not necessary.

Despite what the PSA might expect, the Delegate considered that it is the scope of the claims, as defined by the words used, that must be given due consideration.

The Delegate agreed that the Claims and teaching of the Specification do not require the isolation of compounds LXVI and LXVII, but that this in itself did not help in determining whether as a result of the amendment, a real and reasonable clear disclosure of the invention as claimed had been satisfied. The Delegate recognized that the Claims included the possibility of the compounds in question being in their isolated forms, yet the Specification only disclosed use of a complex mixture containing many compounds.

Since the Specification was silent regarding how a PSA could isolate, identify, or quantify the individual components of the mixture in the presence of the other components in the mixture, the Delegate considered that there was insufficient information in the Specification for PSA to produce the individual compounds absent others and therefore that the PSA would be unable to perform the full scope of the claimed invention without undue burden.

Accordingly, the proposed amendments were rejected.

Take Home Message

For Applicants seeking patent protection of their invention in Australia, this Decision confirms that there is a real need to ensure that the Specification fulfills enablement requirements across the full scope of the claimed invention. As the law currently stands, this does not mean that everything that could fall within the scope of the claim has to be disclosed in the Specification and practically demonstrated to work, but rather, everything that has been explicitly claimed must be practically demonstrated for enablement. This Decision teaches that being silent regarding how a single molecule could be made and yet explicitly claiming “at least one small molecule”, led to the detriment of the amendment request.

The authors take a moment to reflect back to their training years many years ago and wonder whether if the actual inventive concept was identified by first identifying the problem to be solved by the invention, then perhaps this lack of enablement issue would not exist. A possible representative claim could be drafted as follows:

A method of reducing siliceous scale in a Bayer process stream, the method comprising adding an aluminosilicate scale inhibiting amount of a composition comprising N [(hydroxy)alkyloxyalkyl[(trihydroxy)silyl]]-N-alkyldiamine to the process stream.

Such a Claim would avoid the need to explicitly claim both single compounds and mixtures by referring to the common structural features of the relevant compounds used for reducing scale in the Bayer process. It would follow that the question of whether or not production of single compounds has been disclosed would be unlikely to be entertained by the Delegate since that subject matter would not have been explicitly claimed.

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