T 1889/15 - Suffiency of disclosure; burden of proof

Key points

• This is an opposition appeal about insufficiency of disclosure. Claim 1 is for a polymerization process "to produce a polyethylene copolymer having [] an ESCR Index of 1.4 or more". 
• " The findings of the [impugned] decision in respect of lack of sufficiency of disclosure relied solely on the results of examples 17 and 20 [which do not give a polymer with the required ESCR index value] and on the above-noted limited comparability of the examples ["due to multiple variations of reaction parameters, it is not possible on the basis of the examples to isolate the effect of any individual reaction parameter on the properties of the resulting product"]" . The OD concluded, "that the information in paragraph [0017] [of the patent] represented little more than an outline for a research programme." 
• The Board notes that "However, the burden for proving lack of sufficiency rests with the opponent". "[In] T 63/06 the board explained that following grant of a patent there is a presumption of validity. The weight of submissions required to rebut this presumption depends on its strength." There are two cases.
• The first case is that of "strong presumption", "which exists in the situation where the patent contained detailed information on how to put the invention into practice including test results relating to a particular property. In this case detailed information or evidence e.g. in the form of comparative tests was required to establish a lack of sufficiency"
• The second case is that of  "weak presumption", " in the case that the patent did not contain detailed information. In this case less substantial submissions were required - it was adequate to raise serious doubts e.g. by comprehensive and plausible arguments".
• In the case at hand, the patent has the strong presumption because " there are several examples indicating variations of the reaction conditions and a general discussion of how certain of the reaction parameters affect the outcome, in particular the single critical parameter (the ESCR index)". 
• " Thus, applying the above indicated approach there exists a strong presumption of validity in respect of sufficiency of disclosure in the present case, and a commensurately high standard of proof is required on the part of the respondent to demonstrate that this is not the case, e.g. in the form of comparative tests showing that following the teaching of the patent does not make it possible to obtain reliably the defined ESCR index" 
• The opponent had not discharged of its burden. The case is remitted for novelty and inventive step.
• There is also further issue of admissibility of an experimental report filed by Patentee. "It is therefore clear that all evidence was in the hands of the proprietor and that it was a deliberate choice not to provide it during opposition proceedings. In this respect it is not relevant that the opposition division changed their minds at the oral proceedings as the objection was clear as of the filing of the notice of opposition and the evidence was available." Hence, the report is not admitted. 

EPO T 1889/15 -  link

II. The patent was granted with a set of 24 claims, whereby claim 1 read as follows:

"A continuous fluidized-bed gas-phase polymerization process for making a high strength, high density polyethylene copolymer, comprising: contacting monomers that include ethylene and optionally at least one non-ethylene monomer with fluidized catalyst particles in a gas phase in the presence of hydrogen gas at an ethylene partial pressure of 689 kPa (100 psi) or more and a polymerization temperature of 120 °C or less, wherein oxygen is present in the range of from 10 to 600 ppbv based on the ethylene feed rate, to produce a polyethylene copolymer having a density of 0.945 g/cc or more and an ESCR Index (defined as the measured ESCR, based on ASTM D1693, condition B, using 10% Igepal CO-630 in water, divided by the product of 0.0481 and (Density)**(-142), wherein Density values are based on ASTM D1505) of 1.4 or more wherein the catalyst particles are prepared at an activation temperature of 700 °C or less, and wherein the catalyst particles consist essentially of silica, chromium, and titanium."

Reasons for the Decision

1. Admittance of the declaration and experimental report submitted with the statement of grounds of appeal

In the notice of opposition the opponent raised an objection of insufficiency of disclosure which was based on the observation that Examples 17 and 20 did not result in polymers having the required ESCR values. The submissions in respect of example 17 were as follows:

FORMULA/TABLE/GRAPHIC

This statement clearly drew attention to the apparent defect with example 17 and the lack of any indication in the patent as to the cause.

In the light of this submission the patent proprietor would have had a reason to provide in opposition the information submitted with the statement of grounds of appeal relating to example 17. In the letter of 28 November 2018 reference was made to the original experimental data which was reviewed. This statement indicates that the information which would have served to answer this objection was available to the appellant and could have been provided in the response to the notice of opposition, i.e. during the opposition proceedings.

It is therefore clear that all evidence was in the hands of the proprietor and that it was a deliberate choice not to provide it during opposition proceedings. In this respect it is not relevant that the opposition division changed their minds at the oral proceedings as the objection was clear as of the filing of the notice of opposition and the evidence was available.

It is therefore considered that the proprietor should have filed the evidence in opposition if it was intended that it should be evaluated so that it is appropriate for the Board pursuant to Article 12(4) RPBA not to admit the declaration and experimental report provided with the statement of grounds of appeal to the procedure.

2. Main request - sufficiency of disclosure

As noted above, two examples in the patent - 17 and 20 - do not provide polyethylene copolymers having the required ESCR.

The patent contains 21 examples. In examples 1-10 the catalyst had been activated at a temperature of 825°C (paragraph [0086] and Table 1) and hence above the maximum of 700°C specified in operative claim 1.

Examples 11-21 comply with the process features of claim 1. All of these examples provide copolymers having the required density and, with the exception of examples 17 and 20, result in copolymers meeting the requirements of ESCR.

It is true, as observed by the respondent, that due to multiple variations of reaction parameters, it is not possible on the basis of the examples to isolate the effect of any individual reaction parameter on the properties of the resulting product.

However in paragraph [0017] of the patent the effects of various reaction parameters, in particular activation temperature of the catalyst and reaction temperature are discussed with respect to the ESCR, stating that using a lower activation temperature i.e. 600°C or less allows higher polymerisation temperatures to be employed whilst maintaining excellent ESCR and ESCR index. Moreover it is indicated in the same paragraph which further process conditions should be controlled and in which manner if it is desired to obtain the defined ESCR and ESCR index (in particular high ethylene partial pressure and low polymerisation temperature).

The findings of the decision in respect of lack of sufficiency of disclosure relied solely on the results of examples 17 and 20 and on the above-noted limited comparability of the examples, concluding that the information in paragraph [0017] represented little more than an outline for a research programme.

However, the burden for proving lack of sufficiency rests with the opponent (T 16/87, OJ EPO 1992, 212; T 182/89, OJ EPO 1991, 391).

The question of how this burden can be discharged was addressed and developed in decision T 63/06 (24 June 2008, not published in the OJ EPO).

In section 3.3 of T 63/06 the board explained that following grant of a patent there is a presumption of validity. The weight of submissions required to rebut this presumption depends on its strength.

The board then distinguished between two cases:

- "strong presumption" which exists in the situation where the patent contained detailed information on how to put the invention into practice including test results relating to a particular property. In this case detailed information or evidence e.g. in the form of comparative tests was required to establish a lack of sufficiency (T 63/06, section 3.3.1(a));
- "weak presumption" in the case that the patent did not contain detailed information. In this case less substantial submissions were required - it was adequate to raise serious doubts e.g. by comprehensive and plausible arguments (T 63/06, section 3.3.1(b)).

In the present case, as noted above, there are several examples indicating variations of the reaction conditions and a general discussion of how certain of the reaction parameters affect the outcome, in particular the single critical parameter (the ESCR index, above 1.4) the obtaining of which is contested by the respondent.

Thus, applying the above indicated approach there exists a strong presumption of validity in respect of sufficiency of disclosure in the present case, and a commensurately high standard of proof is required on the part of the respondent to demonstrate that this is not the case, e.g. in the form of comparative tests showing that following the teaching of the patent does not make it possible to obtain reliably the defined ESCR index

The respondent has however provided no detailed arguments, let alone verifiable evidence, e,g. in the form of experimental results, to demonstrate any deficiency in the disclosure beyond referring to two examples, which by the - undisputed - submission of the appellant were defective.

Under these circumstances, in particular with reference to the established approach developed in the Case Law the Board can identify no grounds to conclude that the case of lack of sufficiency of disclosure has been proven.

3. Remittal

In the present case the opposition division addressed the issues of novelty and inventive step only for a process which was limited to the presence of trialkyl aluminium during polymerization, whereby this feature, which is not present in claim 1 of the main request, was material to the reasoning of the opposition division in reaching its findings. This means that novelty and inventive step were not addressed for the operative main request in the decision under appeal.

In view of this and considering that both parties requested remittal in case sufficiency were acknowledged, the Board finds it appropriate to exercise its discretion under Article 111(1) EPC by remitting the case to the department of first instance for further prosecution.

Order

For these reasons it is decided that:

1. The decision under appeal is set aside.

2. The case is remitted to the first instance for further prosecution.