T 1115/09 – Epsilonics

Both the patent proprietor and the opponent appealed against the decision of the Opposition Division (OD) to maintain the patent in amended form.

Claim 1 of the main request before the Board (identical to claim 1 of the patent as granted) read: 

Process for the purification from organic impurities of an inert gas stream exiting a solid state polycondensation reactor of an aromatic polyester resin, wherein the gas is added with oxygen or gas containing oxygen and passed on a catalyst bed-containing Pt or a mixture of Pt and Pd supported on an inert porous support at a temperature comprised between 250°C and 600°C, wherein the quantity of the added oxygen is in such an excess over the stoichiometric amount referred to the impurities present in the gas that the gas at the exit of the catalytic bed contains more than 10 ppm oxygen and up to 250 ppm, and the purified gas is recycled to the reactor after drying to remove the water formed in the oxidation stage, characterised in that a deoxidation stage with hydrogen is not present before recycle of the purified gas to the reactor. (my emphasis)

Claim 1 of auxiliary request 1 differed from claim 1 as granted in that the gas at the exit of the catalytic bed is defined as containing “a quantity of oxygen comprised between 10 and 250 ppm” (my emphasis).

In claim 1 of auxiliary request 2, the gas at the exit of the catalytic bed was defined as containing “from 10 to 250 ppm of oxygen, except 10 ppm”. (my emphasis)

The Board found these requests to lack novelty over document D1:

Main request

[2.1] Document D1 (claim 1) discloses a process for the purification of an inert gas from impurities formed of organic compounds, where the gas added with oxygen or gas containing oxygen is circulated on a catalyst bed containing Pt or mixtures of Pt and Pd supported on an inert porous support at temperatures from 250° to 600 °C, the quantity of oxygen used being stoichiometric with respect to the organic impurities or in such an excess that the gas at the outlet of the oxidation reactor contains no more than about 10 ppm of oxygen (my emphasis). D1 (claim 3) further specifies the gas to be purified as coming from a solid-state polycondensation reactor of a polyester resin and that the gas, after purification, is recycled to the solid-state polycondensation reactor after a drying treatment to eliminate the water formed in the oxidation stage.

It is undisputed that the sole issue to be decided is whether D1 discloses a quantity of oxygen in the gas exiting the catalytic bed which falls within the terms of claim 1 or not, and in particular whether an amount of “no more than about 10 ppm of oxygen” falls within the range “more than 10 ppm oxygen and up to 250 ppm”.

[2.2] In this respect, it is a generally applied principle for concluding lack of novelty that there must be a direct and unambiguous disclosure in the state of the art inevitably leading the skilled person to subject-matter falling within the scope of what is claimed.

[2.3] D1 discloses that the gas at the outlet of the catalytic bed contains no more than about 10 ppm oxygen, i.e. a range of oxygen concentrations ending with the upper value of “about 10 ppm”.

According to established case law of the boards of appeal (see e.g. T 240/95 [4.2]), the disclosure of a range is an explicit disclosure of the end values. In the present case it follows by analogy that the end value “about 10 ppm” is explicitly disclosed in D1.

[2.4] The sole question which remains to be answered is whether this end value falls within the range defined in claim 1 at issue, i.e. “more than 10 ppm oxygen and up to 250 ppm”.

In the board’s view, in the absence of a clear definition in document D1 of the relative term “about”, the expression “about 10 ppm of oxygen” is to be given its broadest meaning, namely “10 ± ε ppm of oxygen”, with ε denoting - as in mathematics - a small undefined positive quantity. It follows that the upper end value “about 10” can be read as: “10-ε”, “10” or “10+ε”, which means that document D1 directly and unambiguously discloses a list of three ranges ending respectively with “10-ε”, “10” and “10+ε”.

As the value “10+ε” is synonymous with the value “more than 10”, the choice of the latter as the lower end of the range defined in claim 1 thus boils down to the selection of one discrete value within the list of three: “10-ε”, “10” and “10+ε” disclosed in D1.

[2.5] Following the case law (e.g. T 730/01 [2.3]) according to which the selection of one item within one single list of equivalent alternative items does not confer novelty, in the present case the board concludes by analogy that the disclosure of document D1 inevitably leads to subject-matter falling within the scope of protection of claim 1 at issue.

[2.6] [T]he patentee argued that document D1 taught to work with less than 5 ppm (as in the Example) and even with no oxygen (as in the statement at page 6, paragraph 4: “the gaseous stream at the reactor outlet contains only nitrogen, carbon dioxide and water”). In this context the skilled person would not consider carrying out the process of document D1 with more than 10 ppm oxygen, because there was a risk of degradation of the PET polymer.

The board cannot accept these arguments because even if document D1 discloses that the risk of degradation is limited with a gas leaving the oxidation reactor containing less than 5 ppm oxygen, there is no limitation at all in the claims – let alone in the description – regarding the degree of degradation which might be accepted with the claimed process. Furthermore, it is directly and unambiguously disclosed in D1 […] that a maximum excess of about 10 ppm of oxygen is tolerated at the oxidation reactor outlet.

It follows that the skilled person has no reason to worry about a risk of degradation of the PET polymer within the whole range claimed and he would therefore indeed consider also carrying out the process of document D1 with a gas containing 10+ε ppm of oxygen at the oxidation reactor’s outlet.

[2.7] For the above reasons, claim 1 does not meet the requirements of A 54(1) and (3) (document D1 being state of the art under the meaning of A 54(3)).

Auxiliary request 1

[3.1] Claim 1 of this request defines the quantity of oxygen in the gas exiting the catalytic bed as being “comprised between 10 and 250 ppm”.

[3.2] According to the established case law of the boards of appeal, the wording used for defining the above range is to be considered as an explicit disclosure of the end values “10” and “250”.

The end value “10” being explicitly disclosed in D1 as one of the upper end values of the oxygen concentration range […], the subject-matter of claim 1 at issue lacks novelty under A 54 (1) and (3).

[3.3] The board observes that even if – as argued by […] the patentee – one would consider the value “10” to be excluded by the wording used in above claim 1, the scope of protection of claim 1 would then be the same as that of claim 1 of the main request, since the lower end value of the range would then be the same - apart from the semantic difference - as in claim 1 of the main request. The subject-matter of claim 1 of the first auxiliary request lacks novelty under A 54 (1) and (3).

Auxiliary request 2

[4.1] Claim 1 of this request defines the gas at the exit of the catalytic bed as containing “from 10 to 250 ppm of oxygen, except 10 ppm”.

[4.2] The board observes that – apart from the semantic difference of wording – the lower end value of this corresponds to the one in claim 1 of the main request (“more than 10”) and so, for the same reasons that apply to claim 1 of the main request, the present request is to be rejected under A 54 (1) and (3).

The patent was finally revoked.

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