T 1146/07 (Process for depolymerizing carpet waste/ALLIEDSIGNAL INC. and KONINKLIJKE DSM N.V.) 22-01-2010

1. The appeal is admissible.

Main request

2. Added matter

2.1 The expression "...wherein the non-caprolactam components comprise at least one of jute, polypropylene, latex, calcium carbonate, clay, hydrated alumina filler, dye, soil repellent, stabiliser, dirt or up to 10% by weight of polyethylene terephthalate with respect to polycaprolactam." has been added to the granted version of claim 1.

The respondent argued that such an amendment is fully supported by the paragraphs spanning pages 2 and 3 of the application as originally filed. It also further argued that the detailed description of the invention makes it clear that the multi-component waste may be provided as carpet material (see page 7, lines 29 to 31 of the application as originally filed).

The board does not share this view. Although the passage introduced into claim 1 is mentioned in the paragraphs spanning pages 2 and 3, it however, clearly relates to carpets (see first word of the last paragraph on page 2 of the application as originally filed). Furthermore, lines 1 to 3 on page 7 of the application as originally filed mentions, as a preferred embodiment of the invention, that the caprolactam is recovered from waste carpet material. However, such a wording does not allow concluding that the wording of claim 1 is limited to carpet waste. In view thereof and since claim 1 of the main request is not limited to carpet waste, the introduction into claim 1 of the passage cited above would also include material containing one of the constituents listed in the said added passage but not being necessarily a carpet. Such a teaching cannot be inferred directly and unambiguously from the description as originally filed.

2.2 Claim 1 of the main request thus contravenes the requirements of Article 123(2) EPC.

First auxiliary request

3. Late filed request

3.1 Facing a request, which was late filed, the board has to decide whether such a request can be admitted into the proceedings in view of the requirements set out in Article 13(1) and (3) of the RPBA.

3.2 The appellant argued that this request was late filed and that such a request could have been filed previously, e.g. with the respondent's response to the annex to oral proceedings set by the board and requested therefore that this request not be admitted by the board.

3.3 Although the appellant's assertion, as to the late filing of the first auxiliary request, is correct, it remains that the amendment carried out by the respondent (adding of the word "carpet") was made in order to overcome the reason for which the main request was assessed not to be allowable by the board. Moreover, the adding of the word "carpet" into claim 1 cannot be regarded as a complex amendment. Furthermore, the board is convinced that this amendment does not raise any new unexpected issue, since dependent claim 3 as granted, whose wording is identical to claim 3 of the first auxiliary request, unambiguously refers to waste caprolactam carpet. Hence, the limitation of the claimed scope to carpets does not constitute a new and unexpected subject-matter requiring the postponement of the oral proceedings.

3.4 As a consequence, the board admits this late filed request into the proceedings.

4. Amendments

4.1 With respect to claim 1:

The feature "A process for depolymerizing multi-component carpet waste material comprising polycaprolactam and non-polycaprolactam components to form caprolactam" finds an unambiguous basis in claim 1 as filed and on page 7, lines 1-3. Indeed, nylon-6 is polycaprolactam and the term non-nylon-6 is identical to non-polycaprolactam components.

The feature "wherein said multi-component … and/or oligomeric component" finds support on page 6, lines 11-13.

The feature "in the absence of … is formed" is recited in claim 1 as filed".

The added feature "wherein the non-caprolactam … with respect to polycaprolactam", was contested on the basis of two grounds by the appellant:

The definition of the impurities which may be present in a carpet is found in the preamble of the description and moreover in direct relationship with the process defined in the further paragraph related to a process involving an acidic catalyst. Furthermore, the expression "at least one" has no basis in the description.

However, the definition of the impurities present in a carpet such as set out in the bridging paragraph of pages 2-3 has no link with the subsequent paragraph related to the process involving an acidic catalyst.

Moreover, although the definition of the impurities can be found in the preamble of the invention, this matter is not insuperable if the person skilled in the art can unambiguously derive from the description as a whole that the information present in the preamble apply to the claimed invention. This is the case here since the application as originally filed discloses that "a preferred embodiment is the recovery of caprolactam from waste carpet material that includes nylon-6 face fiber and non-nylon 6 components" (see page 7, lines 1-3). The definition of the carpet given in the preamble applies directly to the term "carpet" of the preferred embodiment cited above and claim 1 reflects this clear and unambiguous relationship.

Regarding the feature "at least one", it is to be noted that the description indicates that the carpets "may" include jute … (see page 2, line 25). This term "may" means of course that one or several impurities can be included but also that no impurity is present. However, it is unambiguously derivable from the application as filed that the process is directed to the depolymerizing nylon-containing waste. An impurity is necessarily present and the term "include" can only be understood if "at least one" impurity is present. The term "at least one" derives, therefore, unambiguously from the description as originally filed.

The subject-matter of claim 1 derives directly and unambiguously from the application as originally filed.

4.2 Claims 2 to 10 are identical to claims 2 to 10 as originally filed.

4.3 Furthermore, such an amendment limits the scope of the patent as granted.

4.4 The requirements of Articles 123(2) and (3) EPC are thus met.

5. Clarity

5.1 The passage added into claim 1 contains the word "dirt". It has to be assessed whether such a word has a clear meaning in the context of the invention.

5.2 The appellant pointed out that this word is not clear, since there is nothing in the description as originally filed describing what it is meant by "dirt" in the context of the invention.

5.3 It is true that the word "dirt" is not given a specific meaning in the description as originally filed. In its preliminary opinion (see paragraph V above), the board had pointed out that the term "dirt" might not be clear. However, this objection had been raised in conjunction with the undefined feed mentioned in claim 1 of the main request, namely "multi-component waste material".

5.4 By contrast, the board has no reason to doubt that in the technical field of the carpets, the term "dirt" has a well recognized meaning. In that respect, the board notes that the preparation oil can be present when manufacturing the fiber (see document (1)), this oil is removed (see document (1)) before the said fiber is further used to make carpets.

5.5 The board concludes that the amendments carried out do not render claim 1 unclear. The requirements of Article 84 EPC are fulfilled.

6. Novelty

6.1 Novelty has not been disputed by the appellant and the board is also convinced that the claimed subject-matter is novel vis-à-vis the disclosure of document (1) (Article 54 EPC).

7. Inventive step

7.1 Document (1) describes a process for the depolymerisation and reprocessing of material consisting of polyamide-6 waste and/or oligomer-containing polyamide-6 waste and/or oligomer-containing lactam residue and/or oligomer-containing lactam by hydrolysis in a pressurized reactor with the addition of water, wherein the material is melted and the melt is maintained continuously at a predetermined temperature and conveyed through the pressurized reactor, the internal pressure of which is regulated by the metered supply of water or water vapor (see col. 1, lines 1-4 and Claim 1). Preferably, the material is brought in the pressurized reactor at a temperature from 230ºC to 290ºC to a uniformly low degree of polymerization with a solution viscosity of more than 1.5 (see col. 2, lines 24-27). In order to save energy, the temperature of the water or water vapor is raised by a heat exchanger beyond the melting point of the polyamid-6 (see col. 4, lines 22-27). The examples 1 to 3 and 5 disclose specific embodiments. In example 1, the waste falling during the spinning of the polyamide silk is melt in an extruder, where a preparative oil in the double scroll extruder, which attaches the waste, is removed during the melting process (see col. 6, lines 18-22). Steam is introduced into the reactor under a pressure of 9.5 bar. After three hours at a temperature of 280ºC, the polymer obtained contains around 10% of monomer (water soluble extract). Example 7 discloses the reprocessing of polyamid-6 and -66 waste material.

7.2 At issue was the question whether or not the process according to document (1) made use of superheated steam. The appellant argued that superheated steam was, as per its definition, steam above its vaporization temperature. Several possibilities for providing steam were indicated in col. 4, lines 10 to 31 of document (1), and a heat exchanger was mentioned as one possibility, so that also superheated steam might be used. In support of its contention, document (2) was provided during oral proceedings. The respondent agreed that this document represented a correct definition of the so called "superheated steam". Therefore, although late-filed and post published the board has no reason not to admit this into the proceedings as common general knowledge.

7.3 The respondent argued that superheated steam would not be formed in any of the arrangements described in document (1). It is necessary in order to form superheated steam to expose saturated steam to surfaces with a higher temperature to bring the temperature of the steam above its evaporating temperature. The saturated seam must be passed through an additional heat exchanger. This may be a second heat exchange stage in the boiler or a separate superheating unit. It was not indicated in example 1 that no liquid water was present.

7.4 Document (2) teaches that superheated steam is steam at a temperature higher than water's boiling point. However, to produce superheated steam in a power plant or for processes (such as drying paper) the saturated steam, from the steam drum, is passed through a super heater. The superheating unit may be radiant, convection or separately fired.

7.5 In the board's judgment, the answer to the question is not clear cut. Indeed, it is not clear that the conditions prevailing in the process of document (1) mentioned above (… Steam is introduced into the reactor under a pressure of 9.5 bar. After three hours at a temperature of 280ºC,) necessarily produces superheated steam because the heat exchanger through which the water or steam flows is not unambiguously described as a superheating unit. According to document (2) the superheating unit may be radiant, convection or separately fired. This information cannot be found in document (1). Furthermore, as pointed out by the respondent, it does not appear from document (1) that liquid water does not condense in the reactor, which condition being required by the term "superheated steam" in claim 1 (see claim 1: " … superheated steam at a temperature of about 250ºC to 400ºC and at a pressure within the range of about 1 atm to about 100 atm and substantially less than the saturated vapor of water at said temperature …" in conjunction with the description, page 13, lines 12-15 : "However, the pressure should be substantially less than the saturation vapor pressure of water under operating temperature to ensure that liquid water does not condense in the reactor" or "Therefore, it is clear that in the current process, no liquid aqueous phase is present", page 11, lines 16-17).

7.6 In conclusion, the claimed subject-matter differs from the process of document (1) at least by the fact that said process does not describe a process for the depolymerisation of carpet waste material comprising polycaprolactam and non-polycaprolactam "wherein the non-polycaprolactam components comprise at least one of jute, polypropylene, latex, calcium carbonate, clay, hydrated alumina filler, dye, soil repellant, stabilizer, dirt or up to 10% by weight of polyethylene terephthalate with respect to polycaprolactam" and involving superheated steam (see claim 1).

7.7 According to the Jurisprudence of the Boards of Appeal, in selecting the closest prior art, the first consideration is that it must be directed to the same purpose of effect as the invention (see Case law of the Boards of Appeal, 5th Ed., I. D. 3.2). This is clearly not the case of document (1) the sole document submitted in the opposition/appeal proceedings since this document does not aim at depolymerizing multi-component carpet waste material comprising polycaprolactam and non-polycaprolactam as defined in claim 1.

7.8 Furthermore, it had to be considered that an objective definition of the problem to be solved by the invention should normally start from the problem described in the contested patent. Only if examination showed that the problem disclosed had not been solved of if inappropriate prior art were used to defined the problem, was it necessary to investigate which other problems objectively existed (see Case law of the Boards of Appeal, 5th Ed., I. D. 4.3.2).

7.9 In view of document (1) the board has no reason to depart from the technical problem as defined in the patent. According to the patent in suit, the technical problem is to propose a method for the recovery of caprolactam from multi-component carpet that includes nylon-6 and non-nylon-6 components. The non-nylon-6 components interfere with caprolactam recovery. For example, alkaline components, such as calcium carbonate filler, neutralize acidic catalysts, such as phosphoric acid, that are conventionally used to promote nylon 6 depolymerization, thus requiring the use of increased amounts of catalysts. Furthermore, polypropylene and latex partially decompose to a mixture of hydrocarbons that co-distill with caprolactam. The remaining, partially decomposed, non-distilled portion, along with the filler and other inorganic components, renders the reaction mixture very viscous and difficult to process in conventional equipment.

7.10 Examples 1, 3 to 8 show that a yield of caprolactam between 87% and 95% can be obtained based on nylon present in the carpet in the conditions of temperature and pressure falling in the ranges defined in claim 1. The board is, therefore, satisfied that the technical problem defined in the patent in suit is solved.

7.11 No document in the prior art mentions a process for depolymerizing multi-component carpet waste material comprising polycaprolactam and non-polycaprolactam as defined in claim 1.

7.12 In contrast, the waste material feed of the method of document (1) is formed as a by-product in polyamide-6 production. Document (1) neither teaches nor suggests that the process disclosed therein could be applied to multi-components products such as carpets. Furthermore, there is no teaching in document (1) to suppress the production of caprolactam dimer during the nylon-6 depolymerisation. On the contrary, document (1) states that the object of the invention discloses therein is to provide polymeric material (see col. 1 and 2, bridging paragraph), whereas the technical problem to be solved of the present invention is to provide monomeric material.

7.13 Therefore, the person skilled in the art seeking to solve the technical problem mentioned above would not have arrived in view of document (1) without inventive ingenuity at the solution defined in claim 1.