In this opposition appeal case, claim 1 before the Board read:
1. A process for producing metal powders comprising the steps of:
- providing a hydride powder of a first metal being selected from the group consisting of tantalum, niobium and alloys of said metals with each other or one or both of them with other metals, the hydride having an oxygen content of under 300 ppm;
- mixing said metal hydride with a metal having a higher affinity for oxygen, and heating the mixture;
- removing the metal having a higher affinity for oxygen from the metal, to form a powder of the first metal having an oxygen content of less than 100 ppm.
The Opposition Division (OD) had dismissed the opponent’s inventive step attack, which was based on a combination of documents D1 and D3, and then pursued:
The Board found the way in which the OD had assessed inventive step to be unsatisfactory, because the lack of inventive step was asserted without referring to any concrete prior art document:
[3.1] [The opponent] submitted that the alleged inventive effect of producing a powder with an oxygen content of less than 100 ppm cannot be achieved simply by following the steps defined in claim 1, and that it has not been shown that the effect is obtained for all the alloys covered by the claim, hence the requirements of A 56 have not been met. It was argued that, although the basic process steps are defined in claim 1, many specific details, such as quantities, particle sizes, temperatures, times etc., which influence the oxygen content, are not present. In particular, Examples 1 and 2 of the patent specification show that, despite following the steps defined in the claim, an oxygen content of below 100 ppm is not obtained. Even Example 3, which results in 75 ppm oxygen, fails to give details of the hydride starting material, which would be important for the desired effect.
[3.1.1] The board agrees that there are many parameters that influence the final oxygen content of the powder. Examples 1 and 2, which are not cited as examples of the invention, show that an oxygen content above 100 ppm is obtained when lower temperatures and shorter times are employed. This, however, does not mean that the technical effect underlying the invention is not achieved. Example 3 demonstrates that when heating takes place at a sufficiently high temperature and for a sufficient length of time, the claimed process leads to a powder having the required oxygen content.
[3.1.2] It may or may not be the case that there is insufficient information, such as details about the tantalum hydride starting material or about other process parameters, for the skilled person to achieve the required oxygen content, but this relates to sufficiency of disclosure (A 83), which is not an issue in these proceedings.
[3.1.3] [The patent proprietor] has shown that the decision under appeal regarding the ground according to A 76 is wrong. In addition, [the patent proprietor] can rely on Example 3 as demonstrating that the inventive effect is plausible, particularly as the skilled person is aware that the properties of tantalum and niobium are similar, as evidenced by D9, page 1, first four lines. Consequently, it was for [the opponent] to put forward reasons as to why the invention could not be worked over the entire scope of the claim. However, that the required effect cannot be achieved for all metals and alloys falling within the scope of the claim has not been substantiated. Hence the board sees no reason to conclude that the invention cannot be worked over the entire scope of the claim.
[3.2] The OD agreed with the above submission of [the opponent] that the claimed subject-matter does not meet the requirements of A 56. It reasoned […] that the claimed process was inventive over the disclosures of D1 and D3 but, citing T 939/92 (“the Agrevo decision”), concluded that the technical problem of reducing the oxygen content to below 100 ppm had not been solved over the whole ambit of the claim.
[3.2.1] As submitted by [the patent proprietor], the reasoning of the OD is incorrect. As set out in T 87/08 [6.3], T 306/09  and T 2375/10 , the requirement of inventive step, as defined in A 56, is based on the “state of the art”. Hence the mere statement that the technical problem is not solved over the whole scope of the claim without reference to prior art amounts to insufficient reasoning for a lack of inventive step. If the conclusion was that the objective problem had not been solved, then the problem should have been re-defined and inventive step assessed on the basis of the re-defined problem.
[3.2.2] T 87/08, T 306/09 and T 2375/10 are consistent with T 939/92 which, despite saying that there was a lack of technical effect, analysed inventive step in light of prior art (points [2.5-6]). In T 939/92 the claim concerned a group of chemical compounds and, on the basis of the prior art, the problem to be solved was to provide alternative compounds having herbicidal activity; since the claim included compounds not having his property, it extended to compounds that were not inventive.
[3.2.3] In T 87/08, T 306/09 and T 2375/10 the opposition or examining divisions gave no analysis whatsoever of inventive step based on the prior art, but merely stated that the purported effect was not achieved over the scope of the claim. This is not quite the same situation as in the present case, where the OD considered the prior art before it, and concluded that the claimed process was inventive [...] but then went on decide that the claimed process nevertheless did not meet the requirements of A 56.
[3.3] So, in assessing inventive step correctly, the prior art must be taken into account, which in the present case means taking D1 into consideration.
As with the contested patent, D1 relates to the production of powders of tantalum, niobium and their alloys having low oxygen contents (column 1, lines 16 to 18). This is the same objective as the disputed patent, hence D1 is a suitable starting point for determining inventive step.
[3.3.1] According to the process of D1, metal powders are heated in the presence of an oxygen-active metal, i.e. a metal having a higher affinity for oxygen; this results in a powder having less than 300 ppm oxygen […].
[3.3.2] The process of claim 1 differs in that a metal hydride containing a lower amount of oxygen is used as the starting powder, and in that the resulting powder has a lower oxygen content (less than 100 ppm).
[3.3.3] [The opponent] argued that the first step in the claimed process is the reduction of the hydride to metal, which then reacts at a higher temperature with the metal having a higher affinity for oxygen, hence is indistinguishable from the process of D1. This may well be the case, but as argued by [the patent proprietor], a different starting material is used in the claimed process, and this has a different structure and morphology which, on the face of it, has an effect, namely it results in a lower oxygen content.
[3.3.4] Irrespective of the magnitude of the specific oxygen contents of the powders of the patent and D1, the oxygen content is defined in claim 1 as being less than 100 ppm, whereas the lowest oxygen content achieved by the process of D1 is 135 ppm […]. The problem to be solved starting from D1 is thus not merely to provide an alternative process, as argued by [the opponent], but to reduce the oxygen content yet further to below 100 ppm.
[3.3.5] According to [the opponent], this results in a powder having worse properties than that of D1. However, [the patent proprietor] has argued convincingly that the purpose of the invention is to produce a powder with a very low oxygen content, and this is itself desirable, irrespective of the fact that may have some disadvantages.
[3.3.6] [The opponent] submitted that the solution to the problem can be found in D3, which discloses a process for reducing the oxygen content of tantalum and niobium powders. [… I]t is said that any tantalum or niobium (columbium) containing material can be treated.
Although Examples 1 to 10 and 12 all concern metallic tantalum, Example 11 discloses a process in which tantalum hydride is used as the starting material. The tantalum hydride powder is heated in hydrogen gas, and the water vapour formed by the reaction of hydrogen with the oxygen in the powder is then “gettered” by a more oxygen-active metal than tantalum, in this example, zirconium. However, the oxygen content is not reduced to less than 100 ppm by the process; it is 1140 ppm in the hydride starting powder and present in a comparable amount in the tantalum powder end product […].
Unlike D3, the process of D1 does not involve heating a hydride powder in a hydrogen atmosphere, so the board agrees with the OD that D1 and D3 concern different processes and it is unreasonable to combine the teachings. Consequently, tantalum hydride is not an obvious alternative to tantalum metal as a starting material for the process of D1. Even if D1 and D3 were to be combined, there is no indication that use of a hydride starting powder results in an oxygen content below 100 ppm.
[3.4] Consequently, the subject-matter of claim 1 is not obvious in light of D1 and D3.
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