T 0378/15 04-05-2018

Reasons for the Decision

Admittance of items of evidence

1. Document A1, A2, A4 to A9 and E23, E25, E27 and E28 were all submitted with the statements of grounds of appeal or replies to them. The admission to the proceedings is left to the power of the Board pursuant to Article 12(4) RPBA.

1.1 A first version of auxiliary request 7 on the basis of which the patent in suit was maintained in accordance with the contested decision had been submitted in a group of eight auxiliary requests filed only one month before the oral proceedings, which represented the first attempt to submit amendments of the granted patent. That first version was, to the exception it did not include the modification of dependent claim 8, identical to the one maintained. The modification that the reinforcing particles were acicular as defined in auxiliary request 7 was not a feature of the claims as granted, so that the filing of E23 and E28 dealing with the use of acicular wollastonite as reinforcing material for polyamides represents a timely and appropriate submission in response to the late filing of auxiliary request 7 before the opposition division and the submissions of the patent proprietor in their statement of grounds of appeals that the use of acicular reinforcing particles was not suggested by the prior art.

1.2 A8 and E25 are excerpts of an encyclopedia showing the meaning of the terms "mineral fibers", "carbon" and "carbon fibers" used in the patent in suit or in the prior art documents alleged to be novelty destroying. The submissions of those documents to merely elucidate the meaning attributed to those terms by the skilled person at the date of filing or priority of the patent in suit is reasonable and does not delay the proceedings in any way.

1.3 Experimental report A6 submitted by the patent proprietor is meant to show the advantages of using mineral particles having a maximum dimension of less than 300 mym or of using wollastonite fibers over carbon fibers. It can be therefore considered to be in response to the finding of the opposition division that no effect had been shown to be obtained over the powder composition described in E11. A7 is a data sheet about the commercial product FILLEX® 2-AH3, i.e. a document explaining the nature of the mineral particles used in the examples of the patent in suit which are also employed in A6. The admissibility of A6 and A7 has not been challenged by the opponents and the Board has no reason to take a different view.

1.4 E27 and A9 were submitted in direct response to the experimental data A6 filed by the patent proprietor on appeal. They provide structural information on the specific wollastonite filler and the carbon fibers used by the patent proprietor in the comparative examples of A6. E27 and A9 in particular provide missing information required to determine whether the technical effect allegedly shown in A6 can be attributed to one of the features of present claim 1, namely the maximum dimension of the reinforcing particles or the use of mineral particles. Hence, the filing of E27 and A9 constitutes an appropriate and timely response to the filing of A6 by the patent proprietor.

1.5 Accordingly, the Board has no reason to make use of its discretionary power under Article 12(4) RPBA and to hold documents A6 to A9, E23, E25, E27 and E28 as inadmissible. As a consequence these documents are in the proceedings.

1.6 A1, A2, A4 and A5 are extracts of Wikipedia cited by opponent 2 in order to demonstrate the meaning to be attributed to certain terms contained in claim 1 as maintained by the opposition division (A1 and A2) or to analyse the disclosure of embodiment 2 of E11 regarding the amount of carbon fibers contained in the composition described therewith. However, the reliability of the information contained in these specific articles of Wikipedia cannot be assessed and/or there is no evidence that the content of those documents was made available to the public before the effective date of filing of the patent in suit. Accordingly, and independently from the question whether or not there was any justification to submit those documents on appeal, those documents cannot be used to prove common general knowledge available at the effective date of the patent in suit and therefore cannot be held to relate in its broadest sense to the case under appeal. Accordingly, the Board makes use of its discretionary power under Article 12(4) RPBA to hold documents A1, A2, A4 and A5 as inadmissible.

2. Documents A14 and A18 were submitted after the reply of the parties within the meaning of Article 12(2) RPBA and their admission to the proceedings is therefore subject to the Board's discretion pursuant to Article 13(1) RPBA.

2.1 A14 is a declaration submitted in response to the argument by the opponents that the comparison offered with A6 cannot demonstrate any technical effect arising from the feature distinguishing the claimed compositions from those disclosed in the closest prior art, since the comparison offered also differed in a further feature, namely the presence of a silane coating. It follows therefore that the filing of A14 is the result of normal developments in the appeal proceedings so that the Board finds it appropriate to exercise its discretion by admitting it into the proceedings (Article 13(1) RPBA).

2.2 A18 is an additional experimental report submitted by the patent proprietor two days prior to the oral proceedings, which concerns the measurement of the same mechanical properties as in A6, but in respect of an uncoated wollastonite. According to the patent proprietor its purpose is to confirm the arguments brought forward in their prior submissions, in particular in view of A14, that the coating of a silane agent on the wollastonite fibers used in the example according to the patent in suit in experimental report A6 does not have any influence of the mechanical properties tested, i.e. in other words that A6 is suitable evidence for the effect alleged to be achieved over the closest prior art. However the argument of the patent proprietor that the submissions based on A18 could not take the opponents by surprise and were in response to the Board's comments in its communication expressing concerns about the persuasiveness of A6 do not constitute any justification for their late filing. The criticism exercised by the Board with respect to A6 in its communication stemmed from exactly the same objection as raised by the opponents in their written submissions as early as with letter of 14 September 2015 of opponent 1 (point 1.3, first full paragraph of page 8) and with letter of opponent 2 of 29 September 2015 (point iii) starting at page 9). Accordingly, the patent proprietor should not have waited until two days before the oral proceedings and more than two years after said submissions of the opponents to file experimental data A18, but submit it in a timely manner to allow the opponents sufficient time to provide a response thereto. While the Board does not find any justification for the late filing of A18, its admittance would also put the opposing party in the position of not being able to properly reply to it without adjournment of the oral proceedings. On this basis, the Board does not admit document A18 into the proceedings (Article 13(1) and 13(3) RPBA).

Novelty over E11

3. E11 defines in claim 8, which refers to claims 6 and 7 dependent on claim 2, a powder composition suitable for selective laser sintering which comprises a polymer powder such as Polyamide 11 or Polyamide 12 and carbon and/or glass fibers as reinforcing material. An example of such powder composition is described in embodiment 2 of E11 (page 15, line 23 - page 16, line 34), whose disclosure is seen by the opponents to anticipate the subject-matter of granted claim 1. 3.1 That embodiment 2 describes in accordance with figure 4 a mixture of a powder of Polyamide 12 with a grain size distribution width d50 of about 50 microns and 10 volume% carbon fibers of two different types with an average fiber length L50 of about 70 microns and a fiber thickness of 7 microns. It is undisputed that the mixture employed in embodiment 2 of E11 is disclosed through the use of the above described carbon fibers to contain at least about 3 weight percent of reinforcing particles having an aspect ratio of at least about 5:1 and a maximum dimension of less than about 300 microns, based on the total weight of the powder composition. The sole issue in dispute concerning novelty over E11 is whether the definition in operative claim 1 that "at least a portion of the reinforcing particles are mineral particles that comprise at least about 1 wt-% of the powder composition, based on the total weight of the powder composition" constitutes a distinguishing feature over embodiment 2 of E11. The opponents submitted in this respect that the term mineral cannot confer any novelty to operative claim 1 as that term, within the meaning of the patent in suit also covers the type of carbon of which are made carbon fibers used in embodiment 2 of E11. 3.2 The excerpts of technical encyclopedia E1 or technical lexicon A8 demonstrate that carbon fibres at the relevant date of filing of the patent in suit were not classified by the skilled person as mineral fibers. This also is not contradicted by the definition of the term "mineral" provided in paragraph [0018] of the patent in suit, namely "any of the genus of naturally occurring inorganic substances (including fossilized organic substances) that typically have a definite chemical composition and a characteristic crystalline structure, color, or hardness. The term encompasses both purified minerals and synthetically-produced equivalents of naturally-occurring minerals", because no evidence was provided showing that the characteristics of carbon fibers also called graphite fibers (see E25, page 2289), let alone those used in E11, corresponded to those of naturally-occurring graphite. The opponents further argued that the term "equivalent" in the definition given in paragraph [0018] was vague so that the term mineral within the meaning of the patent in suit would also include man-made graphite whose characteristics resemble those of naturally-occurring graphite. 3.3 However, it is constant jurisprudence (Case Law of the Boards of Appeal of the EPO, 8th edition, 2016, e.g. I.C.4.1) that a term as used in a document has to be construed in the context of the document taken as a whole and not in isolation. In the presence case, even if one took the position that the term "equivalent" taken alone could designate products whose characteristics resemble the products naturally occurring, one would understand having regard to paragraphs [0004] and [0050] of the specification describing the drawbacks of carbon (graphite) fibers and the need to reduce or eliminate their use by the use of mineral particles that the term "equivalent" used in paragraph [0018] is not meant to allow the wording "mineral particles" to include carbon fibers. 3.4 Accordingly, the objection that embodiment 2 of E11 would anticipate granted claim 1 fails to convince. Inventive step Closest state of the art 4. The patent in suit concerns Laser Sintering (LS) technology (also called selective laser sintering) for which carbon fibers and glass fibers have been considered as filler materials to improve the mechanical properties of LS articles (see paragraphs [0001] to [0004] of the patent in suit). In view of drawbacks linked to the use of carbon or glass fibers which are recited in paragraph [0004], in particular their costs, the patent in suit has the objective to provide improved powder compositions for use in producing LS articles that exhibit suitable mechanical properties at ambient and/or elevated temperatures (see paragraph [0005]) . 4.1 All parties in line with the contested decision argued inventive step starting from the disclosure of E11, in particular from the powder composition of embodiment 2 of that document described in above section 3.1. Having regard to the objective of the patent in suit to improve powder compositions for use in producing LS articles, in particular those comprising glass or carbon fibers, and as indicated in the Board's communication, the undisputed finding that the other prior art documents cited in the proceedings do not come closer to the present invention than E11, the Board is satisfied that E11 represents a suitable starting point for assessing inventive step. 4.2 It follows from the analysis given in respect of novelty over E11 that the powder composition of operative claim 1 differs from those disclosed in E11, only in that it contains at least 1 wt-% based on the total weight of the composition of mineral reinforcing particles having an aspect ratio of at least about 5:1 and a maximum dimension of less than about 300 microns. Having regard the wording of present claim 1, the mineral reinforcing fibers can be used in the absence of or in combination with carbon fibers, as confirmed by paragraph [0050] of the specification. Problem successfully solved 5. Having regard to the disclosure of E11, the patent proprietor submitted that the technical problem solved by the subject-matter of claim 1 of the patent in suit was the provision of powder compositions for use in producing LS articles exhibiting comparable mechanical properties without the need to use carbon or glass fibers. That problem is alleged to be solved by the use of at least 1 wt-% based on the total weight of the composition of mineral reinforcing particles having an aspect ratio of at least about 5:1 and a maximum dimension of less than about 300 microns, which constitutes the feature distinguishing the claimed subject-matter from E11 (see above sections 3.1 to 3.3). 5.1 As to whether evidence has been provided that the claimed subject-matter provides a successful solution to the problem mentioned above, the patent proprietor referred to comparative test A6 which are alleged to demonstrate that mineral particles having an aspect ratio of more than 5:1 and a maximum dimension of less than 300 µm allow the production of three dimensional articles being less brittle and which exhibit lower anisotropy as far as tensile strength is concerned. The test is based on a comparison between three powder compositions, all comprising an unfilled nylon 12 powder and 25 wt% of a reinforcing agent, which is either FILLEX® 2-AH3 (wollastonite particles with an average fiber diameter of 10 µm, an aspect ratio of 15:1 and an "Avg maximum dimension" of 150 µm), NYAD G® (wollastonite particles with an unspecified average fiber diameter, an aspect ratio of 15:1 and an "Avg maximum dimension" of 800 µm) or Toho Tenax A HT M100 100mu (milled carbon fibers with an average fiber diameter of 7 µm, an aspect ratio of 15:1 and an "Avg maximum dimension" of 100 µm). 5.1.1 According to the established jurisprudence, if comparative tests are relied on to demonstrate an inventive step on the basis of an improved effect, the nature of the comparison with the closest state of the art must be such that the alleged advantage or effect is convincingly shown to have its origin in the features distinguishing the invention from the closest state of the art (Case Law, supra, I.D.10.9), i.e. in the present case the presence of at least 1 wt-% based on the total weight of the composition of mineral reinforcing particles having an aspect ratio of at least about 5:1 and a maximum dimension of less than about 300 microns. 5.1.2 The comparison offered with A6 between the powder composition comprising FILLEX® 2-AH3 representing an embodiment of the present invention and the powder composition comprising Toho Tenax A HT M100 is meant to demonstrate the existence of an effect arising from the replacement of carbon fibers by wollastonite fibers. However, that comparison cannot demonstrate any causal link between the effects reported in that test and the replacement of carbon by the mineral wollastonite, since the fibers compared do not only differed by the type of material, but also by their length (150 µm for FILLEX® 2-AH3 vs 100 µm for Toho Tenax A HT M100) and the presence of a coating agent (an aminosilane for FILLEX® 2-AH3 as shown in A7 and the absence of a material applied on the carbon fibers for Toho Tenax A HT M100 as indicated in A9, see legend of the second picture on page 1 and last table on page 2). Accordingly, the technical effects obtained in A6 when replacing Toho Tenax A HT M100 fibers by FILLEX® 2-AH3 fibers cannot be attributed to the nature of the material making the fibers, i.e. wollastonite instead of the type of carbon of which carbon fibres are made.5.1.3 The second comparison relied on by the patent proprietor based on A6 is between FILLEX® 2-AH3 and NYAD G® which comparison aims at showing the advantages of using the maximum dimension of the mineral particles set out in operative claim 1. That comparison, however, is not made with respect of the closest prior art, which does not use wollastonite particles as reinforcing filler, but carbon fibers. It cannot even show that the specific maximum dimension of the particles defined in present claim 1 of less than about 300 microns brings about any advantage in comparison to the closest prior art, since E11 also uses reinforcing particles having a maximum dimension within that range. 5.1.4 It was also submitted by the patent proprietor based on a further comparison provided in A6 between the composition comprising FILLEX® 2-AH3 and the composition comprising NYAD G® that the size of the reinforcing particles defined in claim 1 was not arbitrary, but allowed to achieve both an efficient processing of the powder in laser-sintering machines and desired mechanical properties of the obtained LS articles, meaning that the purposive character of the selection operated by the patent proprietor when defining the size of the mineral particles should be retained for the formulation of the problem solved over the closest prior art. Having regard to A7 and E27 describing the reinforcing materials FILLEX® 2-AH3 and NYAD G®, respectively, it is undisputed that these two fillers do not only differ in their maximum dimension, but also in their chemical composition and the presence of an aminosilane coating for FILLEX® 2-AH3, whereas NYAD G® is untreated. The assertion of the patent proprietor based on declaration A14 that the surface coating FILLEX® 2-AH3 does not provide for any differences in the end parts, meaning implicitly that the effect shown in A6 can be imputed only to the difference in the maximum size of the filler, lacks credibility not only in the light of A7, but also in view of E23. A7 stresses that the coating on FILLEX® 2-AH3 and the form of the filler provide an optimal embedding of the filler in the polymer matrix and a significant increase of the tensile strength, whereas E23 teaches that a coupling agent such as an aminosilane coated on the wollastonite improves the bonding between the polyamide and the mineral surface resulting in an improvement of strength (see last paragraph of page 119, paragraph bridging pages 123 and 124, page 124, last bullet point of section 4.1 and third paragraph of page 126). Based on the above, the nature of the comparative tests submitted with A6 cannot demonstrate a causal link between the dimension of the reinforcing particles which is defined in operative claim 1 and the alleged advantages both in respect of an efficient processing of the claimed composition in laser-sintering machines and in respect of the mechanical properties of the obtained LS articles. Accordingly, the technical effects allegedly arising from the selection of a dimension of the reinforcing particles as defined in operative claim 1 has not been demonstrated either. 5.1.5 It is also undisputed that the reference in A6 to a lower degree of anisotropy in respect of the tensile strength property which is alleged to result from the use of mineral fibers instead of carbon fibers amounts to addressing a technical effect which is not described or even derivable from the description of the invention in the specification, although powder compositions comprising carbon fibres for the production of LS articles as described in E11 correspond to the starting point for the present invention as already identified in the patent in suit at its date of filing (see paragraph [0005] of the application as filed). Accordingly, and independently of the probative value of experimental evidence A6, having regard to the jurisprudence of the Boards of Appeal (see Case Law, supra, I.D.4.4.1 and I.D.4.4.2) there is no justification for accepting a formulation of the problem solved over E11 which would take into account an improvement of homogeneity of the the mechanical properties of the produced LS articles. 5.2 In addition to this, it is noted that according to established case law, if the inventive step of a claimed invention is based on a given technical effect allegedly obtained over the closest prior art, the latter should, in principle, be achievable over the whole area claimed, i.e. the effect can be acknowledged if it is credible that substantially all the claimed embodiments lead to that particular technical effect (Case Law, supra, I.D.9.8.3). As submitted by the opponents no evidence has been submitted to show that further embodiments of operative claim 1, e.g. those using mineral particles other than wollastonite in the absence of carbon fibers, or those using any mineral particle having the dimensions specified in claim 1, including wollastonite, but in the presence of carbon fibers, as explicitly foreseen in the patent in suit (see section 4.2 above), provide a successful solution to the problem formulated by the patent proprietor. Having regard to those embodiments employing carbon fibres the Board cannot accept the formulation of the problem offered by the patent proprietor (see above section 5) which by nature can only concern embodiments which do not use carbon fibres.5.3 Consequently, it follows from the above analysis that the patent proprietor has not presented any corroborating evidence or explanations making it credible that the purported technical benefit of providing powder compositions for use in producing LS articles exhibiting comparable mechanical properties to those obtained in the closest prior art without the need to use carbon or glass fibers is achieved. Accordingly, the technical problem solved over the closest prior art by the claimed subject-matter as proposed by the patent proprietor needs to be reformulated and can only be considered to lie in the provision of further powder compositions which are suitable for laser sintering. Obviousness 6. It remains to be decided whether or not the proposed solution to the objective problem underlying the patent in suit is obvious in view of the state of the art. 6.1 As shown in E11 by its claim 2 and the last paragraph of page 5, the use reinforcing fibres in the powder compositions of that document is not restricted to carbon or glass fibres, so that the skilled person faced with the problem of providing further powder compositions suitable for laser sintering would consider the use of any reinforcing fiber which he would consider suitable for that purpose. E12 also concerned with powder compositions for laser sintering which can be based on nylon (see paragraph [0045] and claim 6) teaches in paragraph [0047] the use of wollastonite as inorganic filler. Wollastonite inorganic filler as shown in E28 is marketed either with a low-aspect ratio (generally 5:1 or less) or a high-aspect ratio (generally 12:1 and higher) (page 1027, right-hand column, lines 4-5), their use for nylon being described in the same paragraph, as well as in Tables 7 and 8 on page 1035. Most importantly, the use of acicular wollastonite as reinforcing filler for polyamides is the subject-matter of a chapter in E23, a monography about plastics technology. E23 in particular teaches the use of acicular wollastonite having an aspect ratio of between 10:1 and 20:1 and a mean length of 90 mym, which material is coated with gamma-aminopropyl-triethoxysilane, i.e. an aminosilane (page 124, last bullet point of section 4.1) when a further improvement of the reinforcing properties is sought (page 126, third paragraph and page 127, Table 4). Moreover, an acicular wollastonite coated with an aminosilane, which is described in the patent in suit as a mineral filler in accordance with the definition of operative claim 1 (aspect ratio 1:15, maximum dimension of less than 300 mym), namely FILLEX® 2-AH3, is not only commercially available, but recommended as reinforcing filler for thermoplastic compounds as shown in A7. Accordingly, starting from E11, in particular from its embodiment 2, the skilled person having in mind the objective to merely provide further powder compositions which are suitable for laser sintering would be guided by the prior art to use FILLEX® 2-AH3 even in a small amount such as 1 wt-% based on the powder composition in replacement of or in addition to the other reinforcing carbon fibres used in embodiment 2 of E11, arriving thereby in an obvious manner at aqueous compositions falling within the ambit of present claim 1. 6.2 The argument of the patent proprietor that the solution proposed by the composition of claim 1 would not be obvious since E23 does not concern the use of wollastonite fibres in laser sintering applications, but merely injection moulding applications, is for the following reasons not convincing. The fact that E23 does not suggest the use of wollastonite in LS application cannot be considered by the skilled person as a deterrent to their use in such applications, since E23 was obviously published before the development of this technology. Moreover, E12 hints at the use of wollastonite in LS applications and E11 even provides on page 16, lines 17-27 the unmistakable indication regarding its embodiment 2 that the mechanical characteristics of the articles obtained in accordance with the laser sintering technology are by no way inferior to those of the injection-moulded articles addressed in E23 which recommends the use of the acicular wollastonite. 6.3 Accordingly, the subject-matter of claim 1 of patent as granted which encompasses obvious embodiments does not meet the requirements of Article 56 EPC with the consequence that the main request is not allowable. Auxiliary requests 1 to 13 7. As can be taken from above sections II and VIII, claim 1 according to auxiliary requests 1 to 13 contains in comparison to claim 1 of the main request various features inserted either alone or as combinations thereof, which features define the maximum dimension of the reinforcing particles which is greater than about 10 microns, the maximum amount of reinforcing particles being mineral particles which is less than 40 wt-% of the powder composition, the chemical nature of the mineral particles which are selected from silicate minerals, calcium minerals, barium minerals, magnesium minerals or combination thereof, or which is defined to be wollastonite or that at least some of the reinforcing particles are acicular. The patent proprietor did not submit that due to their introduction into claim 1 the problem allegedly solved over the closest prior art (see above section 5) should be formulated in a different manner. It is also not apparent to the Board that as the result of their introduction into the various versions of claim 1, the breadth of these claims would be restricted to subject-matters for which the evidence on file would be sufficient for the Board to acknowledge that the problem formulated by the patent proprietor can be considered to be successfully solved over the whole scope of the claims. In particular the experimental evidence on file still concerns comparisons which do not only differ in the feature(s) distinguishing the claimed subject-matter from the closest prior art, or do not concern embodiments comprising the combined use of carbon fibers and mineral fibres, which are still encompassed by the amended claims. Moreover, the additional feature introduced in claims 1 of auxiliary requests 1 to 3, 5, 6 and 8 that the reinforcing particles have a maximum dimension of greater than about 10 microns does not introduce a further distinguishing feature over the closest prior art, whereas the acicular wollastonite fibers described in A7 which represented an obvious solution of the objective problem also fulfill that additional condition, which implies that this feature has no impact on the above analysis of inventive step. As to the feature added to claims 1 of auxiliary requests 2, 3 and 6 defining the maximum amount of reinforcing particles being mineral particles to be less than 40 wt-% of the powder composition, it is also suggested by the state of the art as mentioned above in respect of the use of a small amount of mineral particles such as 1 wt.-% based on the powder composition (see section 6.1). The restrictions that mineral particles must be selected from silicate minerals, calcium minerals, barium minerals, magnesium minerals or combination thereof as defined in claim 1 of auxiliary request 3, or that the mineral particles comprise wollastonite as defined in claims 1 of auxiliary requests 4 to 6 or the definition that at least some of the reinforcing particles are acicular or that the mineral particles comprise acicular wollastonite particles, as defined in claims 1 of auxiliary requests 7 and 8, respectively, do not change the above finding in respect of inventive step, since the mineral particles described in A7 whose use was found to be obvious for merely providing further powder compositions also fulfill those additional requirements, meaning that the amended versions of claim 1 still encompass non-inventive embodiments. As a result, claims 1 of auxiliary requests 1 to 8 must also fail on the same ground. 8. Concerning auxiliary requests 9 to 13 and 6A, whose admittance has been contested, the Board notes that even if those were admitted into the proceedings to the benefit of the patent proprietor, those could not overcome the finding that claim 1 of the main request lacks an inventive step over E11. Despite the restricted definition of the polymer powder in claims 1 of auxiliary requests 9 to 13, those are not further distinguished from the closest prior art, as they still allow the use of polyamide 12 (i.e. Nylon-12) employed in embodiment 2 of E11. The various restrictions of the definition of the polymer powder in claims 1 of auxiliary requests 9 to 13 therefore could have no influence on the above analysis of inventive step. It is also undisputed that the amount of laser-sinterable polymer powder and the amount of reinforcing particles defined now in auxiliary request 6A (see section XII above) would have no influence of the analysis of inventive step. As a result the submissions of those auxiliary requests, whether or not they should be admitted into the proceedings, cannot lead to a conclusion different from that arrived at in respect of the requests of higher ranking.