T 0212/91 (Iodine adsorbens/HITACHI Ltd.) 16-05-1995

1. The appeal is admissible.

2. Admissibility of the late filed evidence: a preliminary point

The admissibility of late filed evidence is a matter of discretion for the Boards, which of course, act in a judicial capacity to decide whether or not the first instance's decision was correct on its merits: (see decisions G 9/91 and G 10/91, OJ 1993, 408 and 420). Whilst those decisions dealt expressly only with the issues of whether or not the Boards of Appeal, as judicial bodies, had the power to decide on matters which went beyond the extent to which the European patent had been opposed (G 9/91) or, (G 10/91) the grounds upon which such opposition had been based, it is clear to this Board that the legal principles in both these cases apply with equal force to the third component of all those matters that Rule 55(c) EPC enjoins the parties to state within the opposition period, namely the "indication of the facts evidence and arguments" in support of the grounds on which the opposition is based. The heart of the matter, of course, is that cases decided by the Boards of Appeal should have the same, or substantially the same, legal and factual framework as the case on the basis of which the first instances decision had been rendered.

Following those principles, new facts and in particular new evidence which do go beyond the "indication of the facts and evidence" presented in the Notice of Opposition in support of the grounds of opposition, should only very exceptionally be admitted into the proceedings, and then only if such material is prima- facie highly relevant, in the sense that it is highly likely to prejudice the maintenance of the European patent in suit. In the Board's judgement there can be no question that in this instance the late filed evidence does relate to a ground, namely insufficiency, upon which the Opposition Division's decision had been based. However, it is equally clear to the Board that, this evidence does substantially alter the factual (but not the legal) framework of the case which the Respondent had to deal with before the first instance (see point III above - the communication annexed to the summons), and, furthermore, it has been filed at a very late stage of the proceedings i.e. more than a year after the Appellants had become aware that the Opposition Division regarded the ground of insufficiency as being unfounded. In exercising its discretion either to admit or to reject such matters, the Board needs to have regard to all the circumstances of the case, including the lack of satisfactory explanation as to why the evidence had been filed in such a tardy manner; that the patent is now some 14 years old, and, lastly and possibly most significantly, that the evidence is not of such a high degree of relevance as to be reasonably likely to change the eventual result in the Appellants' and the party as of rights favour. Having regard to all these considerations, the Board has accordingly decided to exclude the late filed evidence, and also to refuse to hear all insufficiency arguments which are based upon it or are in any way whatsoever related to it.

3. Sufficiency of disclosure

3.1. Appellant 2 submitted that the Opposition Division's finding that the second sintering step to obtain the pores with a mean diameter of 20 to 200 nm does not substantially affect the mean pore diameter of the smaller pores, was incorrect in view of Table 1 of the patent specification, which showed a substantial decrease of the volume of the smaller pores at higher sintering temperatures, whereas the volume of the larger pores is increased at sintering temperatures from 800 to 1200°C. This meant that the mean pore size had been shifted to larger pores.

According to the Respondent, the increase in pore volume of the larger pores could be explained by the difference in pH during gel-forming. For the samples with the same gel-forming conditions, i.e. Nos. 1, 5 and 7, the pore volume of the larger pores was the same at 800 and 1200°C and was only substantially reduced at 1400°C. This reflected the phenomenon that pore volume was reduced at high sintering temperatures. Thus at higher temperatures the pore volume of both the smaller and the larger pores was reduced, but this did not mean that the distribution of the pores was substantially changed.

In view of the total lack of evidence for a significant increase in the mean pore size of the smaller pores during the sintering process for obtaining the larger pores, the Board up holds the finding of the Opposition Division in this respect. Moreover, the present process claim does not require that the mean pore size of the smaller pores in the particles formed in the first step does not change when these particles are bonded together in the second step.

3.2. Appellant 2 further challenged the sufficiency of the patent, on the basis that it did not indicate how particles could be bonded together without a bonding agent, in order to obtain pores between the particles with a mean pore size of 20 to 200 nm. Whilst the Board agrees that such a process is not expressly disclosed in the patent specification, it notes that such a process is not part of claims here at issue. Indeed, in present Claim 1, the second step is defined by the result to be achieved. If this result can only be achieved by the use of a bonding agent as illustrated by the examples, said definition simply implies the use of a bonding agent. Thus the Board finds this insufficiency objection to be unfounded, since the claim excludes processes which do not provide a structure whereby the particles obtained in the first step are bonded in a porous matrix with a mean pore diameter of 20 to 200 nm.

4. Novelty (main request)

4.1. Novelty was attacked by the Appellants on the basis of Example 7 of (1). This example discloses a process for preparing an adsorbing material for adsorbing an organic iodine compound by impregnating porous beads with a silver nitrate solution. The silver taken up reacts readily with organic iodine compounds. The beads were prepared according to Example 6, whereby silicic acid filler particles were mixed with a silica sol to form a suspension, followed by forming spherical droplets thereof, gelling the droplets to obtain a granular material and heating the granules to 700°C for 2 hours to obtain the porous beads. After a subsequent acid treatment and annealing at 700°C for one hour, the beads had a specific surface of 125 m2/g and a pore diameter range of 4 to 200 nm. Of these pores 28% have a diameter less than 10 nm and 10% have a diameter of more than 100 nm.

According to the Appellants, said pore size distribution meant that the beads contained small pores with a pore diameter below 10 nm, derived from the silicic acid filler particles, and large pores with a pore diameter of more than 100 nm in the matrix between the filler particles, derived from the silica sol used to bond the filler particles. Because the above prior art example also disclosed the two-step method of forming small particles in a first step, and binding them in a second step, so that pores with a diameter between 100 and 200 nm were formed between the particles, they submitted that the process of present Claim 1 lacked novelty over (1).

4.2. Apart from the fact that the pore diameters given in Claim 1 relate to mean pore diameters, so that these figures cannot be directly compared with those given in Example 7 of (1), there exists another fundamental difference caused by the requirement of present Claim 1 that in the first step particles having pores with a mean pore diameter of 4 to 20 nm are formed.

The silicic acid filler used in Example 6 of (1) is made up of porous particles, whose pores are, at least, partially filled with water (column 7, lines 45 to 51). The pore size distribution is not given and indeed could not be given, since the current method of determining the pore size distribution is the mercury-porosimeter method as used in the patent in suit, which requires a stabilised pore structure. In the case of a silicic acid gel, the latter requirement means that the particle should be sintered. Since in said prior art Example 6 the filler was not sintered before it was mixed with the sol it could not have had a stabilised pore structure permitting the determination of the mean pore diameter. Thus the method of present Claim 1 is new for the simple reason that in the first step a particle is formed with a stabilised pore structure permitting the determination of the mean pore diameter.

Moreover, the required mean pore diameter of 4 to 20 nm is not necessarily implied by the presence of pores with diameters of between 4 to 10 nm in the sintered beads of Example 7 of (1), since the original pores underwent substantial change by the sintering at 700°C for 2 hours followed by acid treatment and annealing at 700°C for another hour as indicated in Example 6 for the beads used in Example 7.

For all the above reasons the Board confirms the finding of the Opposition Division that the method of present Claim 1 is new.

5. Inventive step (main request)

5.1. The Board considers (1) as the closest prior art, as did the parties and the Opposition Division. As indicated above, both (1) and the patent in suit relate to a process of preparing an adsorption material for the adsorption of organic iodine compounds and both materials have been proven to be highly effective. According to (1), Example 7, CH3I could be removed from a humid gas-stream to an extend of 99.9995%. According to the patent-in-suit, Sample 2, the same compound could be removed with an efficiency of 99.9992%. The conditions under which the removing efficiency was determined were, however, not identical. In the later filed comparative examples the conditions were also not identical so that a fair comparison was not possible. Since other advantages have not been made credible either, the technical problem underlying the invention can only be seen in providing an alternative process for preparing an effective adsorption material for the adsorption of organic iodine compounds.

From the examples given in the patent specification (Table 1), falling within the realm of present Claim 1, it is evident that an effective adsorption material could be obtained, so that the Board is satisfied that the above mentioned problem has indeed been solved by the process of Claim 1.

5.2. It remains therefore to be decided whether, in view of the prior art, the claimed solution would have been obvious to persons skilled in the art.

Present Claim 1 differs from (1) in that in a first step porous particles are formed with a defined pore size distribution.

The general procedure for obtaining the sorption agent as set out in (1), column 4, lines 22 to 49, requires in a first step the forming of silicic acid filler particles which are then suspended in a silicic acid sol. As set out under paragraph 4.2 above, such particles have no defined pore size distribution. There is no indication for the forming of particles with a well defined pore size distribution with a mean pore size of 4 to 20 nm.

In the absence of any other prior art document disclosing a process for preparing an adsorbent by first forming particles with a well defined pore structure before they are mixed with a binding agent, the Board must conclude that the present solution to the said problem would not have been obvious to persons skilled in the art.

5.3. For these reasons the process of Claim 1 of the main request involves an inventive step.

Since the dependent Claims 2 and 3 relate to particular embodiments of Claim 1, the same applies to said claims.

Since the main request is allowed, there is no need to consider the auxiliary requests.