T 0518/08 (Pot and marble/JOHNS MANVILLE) 19-08-2011

Reasons for the Decision

1. Main request - Novelty

1.1 D1 discloses (column 1, lines 30 to 38) glass fibers formed by use of traditional fiber-forming techniques, such as centrifugation, which are quickly and readily degraded when placed in contact with a physiological medium. The glass fibers comprise the following components (D1, column 2, lines 12 to 30):

SiO2: 57 to 70 wt. %;

CaO: 5 to 10 wt. %;

Na2O + K2O: 13 to 16 wt. %;

B2O3: 2 to 12 wt. %;

Impurities: less than 2 wt. %.

The fibers may further comprise one or more of the following additional components (in weight %):

Al2O3: 0 to 5 %;

MgO: 0 to 5 %;

F: 0 to 1.5 %;

P2O5: 0 to 4%, but greater than 0.1% when the amount of Al2O3 is greater than or equal to 1%.

1.2 The specific fibers according to Example 5 of D1 have the following composition (calculated in mol percent):

SiO2: 66.5;

Al2O3: 1.2;

RO (R = Ca + Mg) : 12.2;

R2O (R = Na + K): 15.3;

B2O3: 3.7.

This composition leads to the following (calculated) values for C (acid) = 2.1, C (bio) = 2.2 and C (moist) = 2.6.

The fibers according to Example 5 are further characterised by having a DeltaT (calculated from Table 5 and 6 in D1) of 229ºC.

1.3 It follows that the sole difference between the subject-matter of the different independent claims at issue and the fibers according to Example 5 lies in the method of forming the fibers. In this respect, appellant I referred to paragraph [0020] of the contested patent and specified that the flame attenuated pot and marble process led to fibers structurally different from fibers produced by centrifugal or rotary processes, such as those known from D1. Fibers produced by pot and marble were namely provided with an outer shell depleted of a portion of volatile oxides, while the fibers according to D1 did not have such a shell.

1.4 Therefore, the subject-matter of claim 1 of the main request is novel (Article 54(1) and (2) EPC).

2. Main request - Inventive step

2.1 The alleged invention relates to fiberglass products exhibiting enhanced biosolubility while maintaining other desirable properties and having been prepared from glass compositions suitable for fiberisation by the pot and marble process.

2.2 Regarding the starting point for assessing inventive step, the board considers D1 to represent the closest state of the art for the following reasons.

The board commented on D1 under points 1.1 to 1.3.

Appellant I explained that owing to the structural difference outlined under point 1.3, D1 would not represent the closest state of the art.

The board cannot accept this argument, because even if a structural difference exists between these two kinds of fibers, the fibers of D1 are described to be formed by "use of traditional fiber-forming techniques". So, even if the pot and marble fiberisation process is not explicitly mentioned in D1, this forming process is the sole other "traditional fiber-forming technique" on the market, since it is undisputed that only these two techniques are traditionally used. Therefore, D1 is plainly suitable as the starting point for assessing inventive step.

2.3 Starting from this state of the art, appellant I - referring to paragraph [0004] of the patent in suit - argued that the problem to be solved was to provide glass fibers having improved properties as regards in particular their mechanical strength, resiliency, chemical resistance, moisture resistance and biosolubility.

2.4 As a solution to this technical problem the contested patent proposes glass fibers of the types defined in independent claims 1, 9 and 12, which all three are characterised in that the fibers have been fiberised by a flame attenuated pot and marble process.

2.5 The question is whether the problem identified under point 2.3 has actually been solved.

2.5.1 First of all, the board does not recognise any improvement in favour of the fibers prepared by pot-and-marble over those fibers disclosed in D1 for the following reasons.

Paragraph [0004] of the patent in suit, which tackles the properties mentioned in item 2.3, namely mechanical strength, resiliency, chemical resistance, moisture resistance and biosolubility, concerns the prior art, not the invention. This paragraph furthermore does not disclose any improvement, let alone any improvement over the fibers known from D1.

The contested patent also does not investigate any of the properties (resiliency and mechanical strength) on which the appellant's representative focused during the oral proceedings.

Comparative example 7/Table 5 of the patent in suit - which concentrates on example 6 of document D1 - also does not show any improvement as regards these specific properties.

Also, appellant I did not provide any experimental data confirming its allegations regarding the so-called "improved properties".

2.5.2 According to the patent in suit (paragraph [0009] "Summary of the invention"), it has been "surprisingly discovered that glass fibers of enhanced biosolubility may be prepared from glass compositions suitable for pot and marble processing, which exhibit minimally about a 350ºF difference in HTV and liquidus, and which have well defined formulations meeting both narrow mol percentage composition as well as meeting each of three specific "C-ratios" which govern chemical resistance, moisture resistance, and biosolubility."

So, the contested patent concentrates on the same properties as document D1 (column 4, lines 19 to 27), namely the biosolubility and the chemical and hydrolytic resistance of the glass fibers.

2.5.3 It follows that, in the absence of any improvement, the problem to be solved in the light of D1 has to be reformulated in less ambitious terms, namely as providing further biosoluble, chemically and moisture resistant glass fibers.

2.5.4 The board is satisfied that this problem has effectively been solved, as the contested patent contains enough examples - in particular examples 1, 2 and 3 - showing that biosoluble fibers having the required properties can be produced by the flame attenuated pot and marble process (see table 2).

2.6 It remains to be decided whether the proposed solution (under point 2.4) is obvious in view of the state of the art.

The skilled person starting from the glass fibers known from document D1 and faced with the problem defined under point 2.5.3 would in the board's opinion arrive in an obvious manner at the subject-matter of claim 1 at issue, for the following reasons.

As indicated in items 1.1 and 1.2 above, document D1 discloses biosoluble, chemically and moisture resistant glass fibers, the composition of which falls under the wording of claim 1, inclusive the C (acid), C (bio) and C (moist) values.

D1 further describes that the above biodegradable fibers were formed by use of traditional fiber-forming techniques, such as centrifugation. The glass compositions to be fiberised in D1 were preferably those which had the following characteristics:

- a viscosity of 1000 cps at a temperature lower than about 1200ºC (D1, column 2, lines 57 to 60) (The board observes that this feature corresponds to the HTV (10**(3) poise) defined in claim 1 at issue) and

- a difference between the temperature at which the viscosity of 1000 cps was achieved and the liquidus temperature of greater than about 50ºC (column 3, lines 4 to 6) (The board observes that this feature corresponds to the DeltaT defined in claim 1 at issue).

The DeltaT of the glass compositions described in Table 6 of D1 varies from 122ºC (glass no. 7) to 264ºC (glass no. 8), and the specific glass composition of example 5 of document D1 is characterised by having a DeltaT of 229ºC.

In view of the above and bearing in mind that it was common general knowledge at the priority date (see paragraphs [0005] to [0008] of the patent in suit) that there were only two principal methods of glass wool fiber production: the rotary spinning process and the process by flame attenuation (pot and marble), and that a high DeltaT was a prerequisite for a smooth working of a flame attenuation pot and marble fiberisation process, the skilled person seeking for an alternative fiber glass to those of D1 finds in this document all the ingredients for arriving in an obvious way at the subject-matter of claim 1 at issue.

First of all, the glass compositions disclosed in D1 fulfill all the criteria for obtaining biosoluble and chemically and moisture resistant glass fibers. Furthermore the glass composition of Example 5 has a high DeltaT, which means that it is optimally designed for achieving a smooth working of the flame attenuation pot and marble fiberisation process. In this context, the skilled person, who knows that this is the key criteria for fiberising a glass composition by the flame attenuation pot and marble process, would inevitably try to fiberise this composition by this (sole) other fiberising process with the expectation of getting a glass fiber having similar properties to those of the rotary spun-glass fiber according to example 5 of D1.

Appellant I argued that this reasoning was based on an ex-post-facto analysis and that the skilled person could not arrive at the subject-matter of claim 1 starting from D1, because - as explained in paragraphs [0008] and [0020] of the contested patent - of the huge impact on the biosolubility of the highly resistant shell existing on the surface of pot and marble fibers as a result of the flame attenuation and consequent loss of volatile oxides from the fiber surface. This shell was expected to lower the measured biodissolution rate of a pot and marble fiber by a factor of about 2 to 4 and so, the skilled person could not expect a high biosolubility for the fibers known from D1.

The board cannot accept this argument because even if the skilled man was aware of a certain difficulty of solubilising fibers obtained by pot and marble, there is a strong incentive in D1 to try this fiberisation technique, since D1 (column 3, lines 4 to 7) specifically focuses on composition having a DeltaT of 50ºC or higher. As explained above, a high DeltaT is specifically the key feature for a good working of the fiberisation technique used in the contested patent. So, the skilled person trying this technique on the glass composition according to D1 would directly arrive at a fiber falling within the terms of claim 1 at issue, which therefore lacks the requirements of Article 56 EPC.

It follows that the main request is not allowable.

3. Auxiliary request - admissibility

3.1 At the oral proceedings, appellant I amended the claims so as to introduce the feature "free of phosphates" in independent claims 1 and 12. Independent claim 9 remained unamended.

Appellant II argued that this new request was not admissible because it was belated and furthermore, it raised new issues which had never been brought to discussion before.

3.2 The board observes that the three independent claims 1, 9 and 12 of the new auxiliary request have not been amended in a uniform way. This raises the question which feature in each independent claim is essential for solving the problem at the basis of the contested patent. The question also arises whether each of these features contributes to the technical solution or whether their combination is at stake.

3.3 In view of these new issues that the amended claims submitted at this late stage in the appeal proceedings raises, the board exercises its power of discretion (Article 13(1),(3) RPBA) and decides not to admit the amended claims into the proceedings. In this respect, the board observes that it is established case law of the boards of appeal that when new claims are submitted, these should be clearly allowable in the sense that they do not introduce new objections under the EPC and overcome all outstanding objections (T 1126/97 (not published in the OJ EPO), point 3.1.2 of the reasons). The amended claims should also not raise new issues which would require a further written phase in order to be properly dealt with (T 81/03, point 2.4 of the reasons).

3.4 As the claims of the present auxiliary request clearly do not fulfil the conditions set out in the above decisions, none of the requests is allowable.