T 0036/10 01-03-2012

Summary of Facts and Submissions

I. By its decision posted on 15 October 2009 the opposition division revoked European patent No. 1 302 554. The opposition division held that claim 1 as granted was not allowable for lack of novelty in view of document

D1: V. V. Tetyukhin: "Current State of Russian Titanium Industry and VSMPO; Development of New High Strength Alloys for Aircraft and Civil Engineering", Proceedings of the 1997 International Conference on Titanium Products and Applications, 1998, ISBN: 0-935-297-24-3; International Titanium Association, 1871 Folsom Street, Suite 200, Boulder, Colorado, 80302-5714, USA, pages 37 to 41, 54.

II. The appellant (patent proprietor) lodged an appeal against this decision on 3 December 2009, paying the appeal fee on the same day. The statement setting out the grounds of appeal was filed on 25 February 2010.

III. Oral proceedings took place before the Board on 1 March 2012. The following requests were made:

The appellant requested that the decision under appeal be set aside and the patent be maintained as granted or, in the alternative, on the basis of the first or second auxiliary requests filed on 1 February 2012.

The respondent requested that the appeal be dismissed.

IV. Claim 1 of the patent as granted (main request) reads as follows:

"Titanium-based alloy containing aluminum, vanadium, molybdenum, chromium, iron and titanium which distinction is that it contains components in the following proportion, % by mass:

aluminum 4.0-6.3

vanadium 4.5-5.9

molybdenum 4.5-5.9

chromium 2.0-3.6

iron 0.2-0.5

titanium the balance

while the molybdenum equivalent Mo3KB >= 13.8, wherein the molybdenum equivalent is determined by the following relation:

Mo3KB = %Mo/1 + %V/1.5 + %Cr/0.6 + %Fe/0.4."

Claim 1 of the first auxiliary request differs from claim 1 of the main request by the additional feature (in bold added by the Board):

"Titanium-based alloy containing... while the molybdenum equivalent is Mo3KB >=13.8 - 14.4, wherein... + %Fe/0.4."

Claim 1 of the second auxiliary request further differs from claim 1 of the main request by a point-like selection of the elements of the claimed alloy (also in bold added by the Board):

"Titanium-based alloy containing aluminium, vanadium, molybdenum, chromium, iron and titanium which distinction is that it contains components in the following proportion, % by mass:

aluminium 5.2

vanadium 5.1

molybdenum 5.0

chromium 3.0

iron 0.4

titanium the balance

while the molybdenum equivalent Mo3KB is 14.4, wherein the molybdenum equivalent is determined by the following relation:

Mo3KB = %Mo/1 + %V/1.5 + %Cr/0.6 + %Fe/0.4."

V. The appellant's arguments relevant to the present decision can be summarized as follows:

The composition of the titanium-based alloy claimed in the patent was defined, inter alia, by an iron content ranging from 0.2 to 0.5% and a Mo-equivalent Mo3KB >=13.8. Since these features were not disclosed for the alloys in D1, novelty arose for these reasons alone.

Document D1, page 40, first paragraph, described the nominal composition of titanium alloys VT22 (Ti-5Al-5Mo-5V-1.3Cr-1.3Fe), which served as a basis for developing alloy VT22M (Ti-5Al-5Mo-5V-3Cr). It was evident that in VT22M iron was removed from alloy VT22 (i.e. was present at the impurity level, but not exceeding 0.5%), while the chromium content was increased. Consequently, iron was a nominal constituent in alloy VT22, but not in alloy VT22M.

Moreover, alloy VT22M was unambiguously defined by exhibiting a molybdenum equivalent of 13.5, which was lower than that required for the claimed alloy (D1, page 41, 2nd paragraph and Figure 10 on page 54). It was therefore clear for the person skilled in the art reading the disclosure of document D1 that alloy VT22M was determined by three features which had to be satisfied:

(i) the nominal composition Ti-5Al-5Mo-5V-3Cr,

(ii) an iron content not exceeding 0.5% and

(iii) a Mo-equivalent of 13.5.

It was to be noted that feature (iii) was not in contradiction to feature (ii). Accordingly, the person skilled in the art putting into practice alloy VT22M would interpret the teaching of D1 without any contradiction by choosing a composition satisfying all three criteria. In consequence thereof, the skilled person would not seriously contemplate iron contents above the impurity level for alloy VT22M. Certainly, there was no incentive whatsoever to the person skilled in the art to consider a Mo-equivalent other than 13.5 associated with a higher iron content of 0.5% Fe, for example.

The subject matter of granted claim 1 according to the main request was therefore novel over D1.

As to claim 1 of the first auxiliary request, paragraphs [0014] to [0018] of the A1-published application as filed specifically described a Mo-equivalent of 14.4 for alloy 1 exhibiting mechanical properties superior to those of comparative alloy 2 in Table 1. Hence the upper limit for the range for the Mo-equivalent claimed in the first auxiliary request was originally disclosed.

The same arguments applied to the point alloy composition set out in claim 1 of the second auxiliary request, which was based on alloy 1 of Table 1 of the application as originally filed. The claimed alloy differed from alloy VT22M by the contents of Al, V, Fe and the Mo-equivalent. Since D1 neither disclosed the claimed titanium alloy composition nor provided any incentive or pointer making it obvious for the person skilled in the art to select the point composition of the claimed titanium alloy, the subject matter of claim 1 of the second auxiliary request was novel and involved an inventive step.

VI. The respondent's arguments relevant to the present decision can be summarized as follows:

The skilled person reading document D1 would have understood the disclosure of alloy VT22M to be an alloy having a nominal composition of Ti-5Al-5Mo-5V-3Cr and an iron content which was permitted to vary between the impurity level and 0.5%. One specific embodiment of alloy VT22M was stated to have a Mo-equivalent of 13.5, as was described on page 41 and Figure 10 of D1. There was, however, no disclosure anywhere in document D1 of the formula that was used for calculating the Mo-equivalent. Calculated with the formula given in the patent at issue, the exemplified embodiment of alloy VT22M having a Mo-equivalent of 13.5 exhibited an iron content of 0.08%. However, alloy VT22M was not restricted to this particular embodiment. Following the teaching of D1 according to which the iron content should not exceed 0.5%, the skilled person was free to permit an iron content within the whole range, irrespective of the Mo-equivalent. The maximum allowed and explicitly disclosed value for iron (0.5%) in alloy VT22M matched exactly the upper limit for iron of the claimed alloy and corresponded to a Mo-equivalent of 14.6 which was above the claimed proviso of Mo3KB >= 13.8. Hence, the subject matter of claim 1 as granted was anticipated by the disclosure of D1.

Turning to claim 1 of the first auxiliary request, the introduction of the upper limit of 14.4 was not disclosed independently anywhere in the application as filed but was derived from example alloy 1 in Table 1 of the patent. A range for the Mo-equivalent between >= 13.8 to 14.4 was not disclosed either and therefore contravened Article 123(2) EPC.

The point composition featuring in claim 1 of the second auxiliary request represented merely a workshop modification of the nominal composition of alloy VT22M. According to D1, page 41, first paragraph, alloy VT22M could provide a strength between 1200 to 1350 MPa at an elongation of more than 6% and exhibited a satisfactory ductility and crack resistance. Hence no particular technical problem was solved or technical advantage was achieved by the selected point composition.

Consequently, the subject matter claim 1 of the second auxiliary request did not involve an inventive step vis-à-vis the technical disclosure of document D1.