DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Specification
Paragraph [0030] of the specification is objected to because it is lacking in clarity and contains apparent inconsistencies. Paragraph [0030] is as follows (emphasis added):
Also, the quality of cracker feedstock is higher when the depolymerization oil obtained from real plastic waste has low values of C6-C8 aromatics and Internal Olefin Index (I.O.I.). This latter is defined as the molar ratio between internal double bonds with respect to double bond in chain end position (alfa-olefins) determined as described in the characterization section. Preferably, in the liquid depolymerization product the IO.I. is lower than 1%wt and more preferably lower than 0.5%wt.
This disclosure appears to define IOI as the molar ratio of internal double bonds to chain end double bonds. If IOI is indeed a molar ratio, then how can it be defined in terms of weight %? Considering that IOI is apparently defined as a ratio of one type of double bond (internal double bonds) to another type of double bond (chain end double bonds), it does not seem appropriate to express IOI even in terms of mol percentage.
Claim Objections
Claim(s) 1 is/are objected to because it contains/they contain informalities.
With regard to claim 1: In line 1, replace “the steps of” with --steps of--.
Appropriate correction is required.
Claim Rejections - 35 USC § 112(b)
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 1-15 rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claim 1 recites the limitation "the melt product obtained in (a)" in line 4. There is insufficient antecedent basis for this limitation in the claim.
Furthermore, step (a) as presently claimed is merely a step of “providing a melt plastic waste feedstock”. While one could fairly characterize a step of “providing a melt plastic waste feedstock” as yielding a “melt product” (said melt product being the melt plastic waste feedstock), the fact that step (b) refers to a “melt product” rather than simply --the melt plastic waste feedstock-- suggests that step (a) involves more than simply providing a melt feedstock.
For the purposes of examination, step (a) has been treated as a step of melting a waste plastic feedstock to obtain a melt product.
Applicant should amend claim 1 to clarify as appropriate.
Claim 1 recites “a catalyst comprising a supported heteropolyacid, having a transition metal portion containing transition metals selected from the group consisting of W, Mo, and V and a non-metal portion containing non-metal elements selected from the group consisting of Si, P, and As” (emphasis added).
As presently worded, this limitation requires that the heteropolyacid comprises metals, i.e. more than one metal, selected from the group consisting of W, Mo, and V, and elements, i.e. more than one element, selected from the group consisting of Si, P, and As. However, a review of the dependent claims suggests that Applicant’s intent is for claim 1 to require that the heteropolyacid comprise at least one metal selected from the group consisting of W, Mo, and V and at least one element selected from the group consisting of Si, P, and As.
Namely, dependent claims 10 and 11 require that the catalyst is tungstosilicic acid. Tungstosilicic acid comprises Si and W, but does not comprise any of Mo, V, P, or As. Thus, if claims 10 and 11 are to be proper dependent claims, then claim 1 must be treated as requiring merely one or more of Si, P, and As and one or more of W, Mo, and V.
To overcome this rejection, Applicant should amend claim 1 to recite --a catalyst comprising a supported heteropolyacid, having a transition metal portion containing one or more transition metals selected from the group consisting of W, Mo, and V and a non-metal portion containing one or more non-metal elements selected from the group consisting of Si, P, and As--. Claims 2-15 are rejected due to their dependency on indefinite claim 1.
Claim 2 recites the limitation "the amount of catalyst" in line 1. There is insufficient antecedent basis for this limitation in the claim.
Claim 3 recites the limitation "the support" in line 2. There is insufficient antecedent basis for this limitation in the claim.
Claim 5 recites the limitation "the transition metal compound comprising W or Mo" in lines 2-3. There is insufficient antecedent basis for this limitation in the claim.
Note: Claim 6 also recites "the transition metal compound comprising W or Mo".
Claim 6: Recites “wherein the heteropoly acid further comprises additional transition metal compounds”. Examiner understands “additional transition metal compounds” as referring to additional transition metal elements other than W or Mo. Note: When the heteropoly acid include W, the additional transition metal elements may include Mo and vice versa.
Regardless, as presently worded, the limitation “additional transition metal compounds” requires the presence of multiple additional transition metals in the heteropoly acid. Considering that Applicant included a similar and apparently unintentional requirement for multiple transition metals in claim 1 (see 112(b) rejection of claim 1 above), Examiner believes that the requirement to multiple additional transition metal elements in claim 6 is also unintentional.
Having reviewed Applicant’s specification, Examiner has been unable to find any disclosed examples of a heteropoly acids having one additional transition metal element, let alone multiple additional transition metal elements, as is apparently required by claim 6. Accordingly, Examiner is unable to verify Applicant’s intentions with claim 6.
Examiner notes that the specification includes disclosures of catalysts comprising additional transition metal elements in the support material or in an additional material (a material other than the support or the heteropoly acid). However, Examiner sees no disclosure of a specific heteropolyacid containing multiple transition metal elements.
For the purposes of examination, claim 6 is treated as requiring that the heteropoly acid comprise multiple additional transition metal elements.
Claim 7 recites the limitation "the non-metal element comprising Si or P" in lines 2-3. There is insufficient antecedent basis for this limitation in the claim.
Claim 8 recites the limitation "the non-metal element comprising Si" in line 2. There is insufficient antecedent basis for this limitation in the claim.
Claim 9 recites the limitation "the amount of transition metal" in line 2. There is insufficient antecedent basis for this limitation in the claim.
Claim 9 recites the limitation "the total amount of supported catalyst" in line 3. There is insufficient antecedent basis for this limitation in the claim.
Claim 12 recites the limitation "the transition metal compound" in line 2. There is insufficient antecedent basis for this limitation in the claim.
Claims 9 and 12 recite “the total amount of supported catalyst”. It is unclear if “the total amount of supported catalyst” is calculated as the mass of the of catalyst, i.e. the heteropolyacid, which is disposed on a catalyst support, or if it is calculated to include the mass of the catalyst support.
The plain meaning of the term “the total amount of supported catalyst” suggests that the mass catalyst support is to be excluded. However, at least when the transition metal compound is W, it seems that it is not possible for the heteropolyacid catalyst to comprise merely 1-15 wt% W unless the mass of the support is included in the mass of the catalyst.
Therefore, for the purposes of examination, “the total amount of supported catalyst” has been interpreted as including the mass of the catalyst support.
Applicant should amend claims 9 and 12 to clarify as appropriate.
Claim 13 recites the limitation "the amount of liquid depolymerization product" in lines 1-2. There is insufficient antecedent basis for this limitation in the claim.
Claim 14 recites the limitation "the amount of the higher than C28 fraction in the liquid depolymerization product" in lines 1-2. There is insufficient antecedent basis for this limitation in the claim.
Claim 14 recites the limitation "the higher than C28 fraction" in line 2. There is insufficient antecedent basis for this limitation in the claim.
Claim 14 recites the limitation "the total amount of liquid depolymerization product" in lines 3-4. There is insufficient antecedent basis for this limitation in the claim.
Claim 15 recites an “the Internal Olefin Index (I.O.I)”. The scope of the Internal Olefin Index is unclear for reasons which will be apparent from the specification objection above.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
Claim(s) 1, 2, 4, 5, 7, 9, 12, 13, 14, and 15 is/are rejected under 35 U.S.C. 103 as being unpatentable over Kumar et al. (US 2012/0016169) in view of Yalcin (“PERFORMANCE OF TPA LOADED SBA-15 CATALYST IN POLYPROPYLENE DEGRADATION REACTION”) and Aydemir et al. (“Synthesis of TPA impregnated SBA-15 catalysts and their performance in polyethylene degradation reaction”), hereafter referred to as Aydmir.
With regard to claim 1: Kumar teaches a process for depolymerizing plastics (abstract, Figure 1, paragraphs [0017]-[0023]), the process comprising:
a) Melting a plastic waste feedstock comprising polyethylene and polypropylene to produce a melt product (Figure 1, paragraphs [0017]-[0023], especially paragraphs [0019] and [0020]).
b) Subjecting the melt product to a temperature in the range of 300-600 °C to thereby obtain a depolymerization product (Figure 1, paragraphs [0017]-[0023], especially paragraph [0020]).
Wherein the melt product is contacted with a catalyst in a depolymerization reactor during step b to facilitate depolymerization of the melt product (Figure 1, paragraphs [0017]-[0023], especially paragraph [0020]). Because the melt product is contacted with the catalyst to facilitate the depolymerization, it is understood that at least a portion of the depolymerization product will also be contacted with said catalyst upon being formed.
“The catalyst used is [Fe--Cu--Mo--P]/Al.sub.2O.sub.3 which is disposed on a stirring blade of the high pressure reactor. The catalyst is prepared by binding a ferrous-copper complex to an alumina support and reacting it with heteropolyacid to obtain the final catalyst,” (paragraph [0020]).
The process of Kumar is fairly characterized as a process of recycling plastic waste. Accordingly, the polyethylene and polypropylene in the waste plastic feedstock are implicitly recycled polyethylene and polypropylene by virtue of being used as a feedstock for Kumar’s process.
In the alternative, i.e. if the term “recycled polyethylene and polypropylene” is treated as requiring that the polyethylene and polypropylene are comprised of polyethylene and polypropylene that have already been recycled at least once in the past, e.g. by some other recycling process, then it would have been obvious to one of ordinary skill in the art to use such “recycled polyethylene and polypropylene” as the feedstock in Kumar. To elaborate, polyethylene is polyethylene regardless of whether or not its been recycled previously. The same is true of polypropylene. Accordingly, a person having ordinary skill in the art would recognize polyethylene and polypropylene from substantially any source, including sources which have already been recycled at least once, as being suitable for use as the polyethylene and polypropylene in the feedstock of Kumar.
If it is not implicit that the plastics in Kumar are recycled plastics, then it would have been obvious to one of ordinary skill in the art before the effective filing date to modify Kumar by using a feedstock comprising recycled polyethylene and polypropylene, in order to obtain a predictably functional process wherein the feedstock is still comprised of polyethylene and polypropylene.
It is unclear to Examiner whether or not the catalyst in Kumar can be fairly considered to comprise a “supported heteropolyacid”. Examiner respectfully requests Applicant described their position on the matter.
Regardless, assuming that the catalyst in Kumar cannot be fairly considered to comprise a “supported heteropolyacid”, the use of such a catalyst is an obvious alternative to the use of the catalyst in Kumar.
Yalcin teaches the use of a, tungstophosphoric acid (TPA) loaded SBA-15 catalyst to depolymerize polypropylene (pages v and vi). Said catalyst represents a catalyst comprising a supported heteropolyacid, i.e. the TPA, said heteropolyacid being supported on the SBA-15. Said heteropolyacid (TPA) comprises a transition metal portion comprising W and a non-metal portion comprising P. The use of the said TPA loaded SBA-15 decreases the activation energy of polypropylene depolymerization (degradation) (page vi).
Aydemir teaches the use of a TPA loaded SBA-15 catalyst to depolymerize polyethylene (abstract). The use of said TPA loaded SBA-15 decreases the activation energy of polyethylene depolymerization (degradation) (abstract).
In view of Yalcin and Aydemir, a TPA loaded SBA-15 catalyst is clearly a suitable catalyst for carrying out a depolymerization of a mixed polyethylene and polypropylene waste feed.
It would have been obvious to one of ordinary skill in the art before the effective filing date to modify Kumar in view of Yalcin and Aydemir by using a TPA loaded SBA-15 catalyst as the catalyst for facilitating the depolymerization reaction in the method of Kumar, in order to obtain a predictably functional depolymerization process wherein the catalyst decreases the activation energy of the polyethylene and polypropylene depolymerization reactions.
With regard to claim 2: Modified Kumar is silent to the catalyst being present in an amount of 1-20 wt% with respect to a total weight of the plastic waste feedstock and the catalyst.
However, a person having ordinary skill in the art would recognize that the amount of catalyst relative to the amount of feedstock is a result effective variable. Namely, a person having ordinary skill in the art would recognize that if the amount of catalyst is too small, then there will not be sufficient catalyst to catalyze the depolymerization of the waste plastic feed. On the other hand, if the amount of catalyst is too large, the process will be inefficient due to an excessive use of catalyst. "[When] the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation," (see MPEP 2144.05 II A).
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Kumar by optimizing the amount of catalyst present, i.e. such that the catalyst is present in an amount of 1-20 wt% with respect to a total weight of the plastic waste feedstock and the catalyst, in order to obtain a method which uses sufficient amounts of catalyst to catalyze the depolymerization without using an excessive amount.
With regard to claims 4, 5, and 7: In modified Kumar, the catalyst is a TPA tungstophosphoric loaded SBA-15 catalyst (see rejection of claim 1 above). Said catalyst comprises W (tungsten), P (phosphorous), and an inorganic oxide support, i.e. the SBA-15.
With regard to claims 9 and 12: In modified Kumar, the catalyst comprises W.
Modified Kumar does not explicitly teach that the W is present in an amount ranging from 1-15 wt% based on a total amount (mass) of the catalyst.
However, the weight percent of the tungsten in the catalyst is merely a reflection of the relative amounts of heteropolyacid and support material present in the catalyst. As the heteropolyacid is the portion of the catalyst which has the catalytic effect (see Aydemir: Introduction), a person having ordinary skill in the art would recognize that the amount of heteropolyacid relative the support material is a result effective variable. Namely, if there is relatively too little heteropolyacid, the catalyst will not make an efficient catalyst. On the other hand, if there is relatively too much heteropolyacid, the available support material will be insufficient to support said heteropolyacid. "[When] the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation," (see MPEP 2144.05 II A).
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Kumar by optimizing the relative amounts of heteropolyacid and support material, such that the transition metal, i.e. W, present in the heteropolyacid is present in an amount 1-15 wt% based on a total amount (mass) of the catalyst, in order to obtain a catalyst which is efficient and properly supported.
With regard to claim 13: Modified Kumar does not explicitly teach that an amount of liquid depolymerization product is higher than 60% wt. of the initially fed plastic waste feedstock.
However, the teachings of Yalcin show that the yield of liquid product can be manipulated by manipulating process variables (Section 6.3, pages 81-83, Figure 6.13). With this in mind, a person having ordinary skill in the art would recognize that it is possible to optimize a plastic depolymerization reaction so as to attain a desired yield of liquid products.
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Kumar in view of Yalcin by optimizing the depolymerization reaction so as to attain desired yield of liquid product, e.g. a yield of 60 wt% or greater relative to the weight of the plastic feedstock.
With regard to claim 14: In modified Kumar, at least a portion of the depolymerization product is liquid (Yalcin: Section 6.3.2, pages 86-89, Figures 6.16 and 6.17, Aydemir: Results and discussion section, especially the final sentence thereof; Kumar: paragraph [0022]).
Modified Kumar does not explicitly teach that the liquid depolymerization product contains less than or equal to 4 wt% of C28 fraction or higher.
However, Aydemir’s teachings show that depolymerizing polyethylene in the presence of the TPA loaded SBA-15 catalyst yields a liquid product comprising hydrocarbons in the range of C8-C14 (Results and discussion section, especially the final sentence thereof). Yalcin’s teachings show that depolymerizing polypropylene in the presence of the TPA loaded SBA-15 catalyst yields a liquid product comprising hydrocarbons, the majority of which are C8-C14 hydrocarbons (Section 6.3.2, pages 86-89, especially the final paragraph on page 88). In view of these teachings, a person having ordinary skill in the art would expect that the process of Modified Kumar would yield a similar liquid product. These teachings also suggest that it is at least possible for the process of modified Kumar to be carried out so as to yield a liquid product containing less than 4 wt% of C28 fraction or higher.
Furthermore, Yalcin’s teachings clearly indicate that the yield of various hydrocarbons in the liquid product can be manipulated through the manipulation of several process variables. Thus, a person having ordinary skill in the art would recognize that it would be possible to manipulate the yield of C28 or higher hydrocarbons in the process of modified Kumar.
A person having ordinary skill in the art would recognize that the fraction of C28 or higher hydrocarbons in the liquid product is a result effective variable, as the amount of C28 hydrocarbons will affect the quality of the liquid product. Namely, a large amount of C28 or higher hydrocarbons in the liquid product will cause said liquid product to become viscous or solidify. "[When] the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation," (see MPEP 2144.05 II A).
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Kumar in view of Aydemir and Yalcin by optimizing the yield of C28 or higher hydrocarbons, such that the liquid depolymerization product comprises less than or than or equal to 4 wt% of C28 or higher hydrocarbons, in order to yield a liquid product which is actually liquid and not overly viscous.
With regard to claim 15: The feedstock in modified Kumar is a mixture of polyethylene and polypropylene (Kumar: Figure 1, paragraphs [0017]-[0023], especially paragraphs [0019] and [0020]). Polyethylene and Polypropylene comprise no internal double bonds. Accordingly, it is understood that any liquid depolymerization product thereof will implicitly have an I.O.I of 1 or less (I.O.I being the ratio of internal double bonds to chain end double bonds).
In the alternative, for the aforementioned reason, a person having ordinary skill in the art would have a reasonable expectation that a mixture of polyethylene and polypropylene could be depolymerized to yield a liquid depolymerization product having an I.O.I of 1 or less. Furthermore, a person having ordinary skill in the art would have a reasonable expectation that the I.O.I. of said liquid product can be ensured to be 1 or less simply by excluding any polymers having internal double bonds from the waste plastic mixture of polyethylene and polypropylene.
Assuming it is not an inherent result of the method of modified Kumar, it would have been obvious to one of ordinary skill in the art to further modify Kumar by carrying out the process to yield a liquid depolymerization product having an I.O.I of 1 or less, in order to obtain, with predictable success, a product having low amounts of internal double bonds.
Claim(s) 3 is/are rejected under 35 U.S.C. 103 as being unpatentable over Kumar in view of Yalcin and Aydemir, as applied to claim 1 above, and in further view of Kumar et al. (2015/0361374), hereafter referred to as Kumar II.
With regard to claim 3: Kumar is silent to the ratio of polyethylene to polypropylene being 85:15 to 15:85.
However, Kumar II, which is by the same first inventor and drawn to a highly similar process to that of Kumar (see Figure 1), teaches that the method can be carried out on “a mixture including any combination of LDPE, LLDPE, HDPE, and PP” (paragraph [0024]). This teaching suggests that it is suitable to carry out the method of Kumar on a mixture comprising polyethylene and polypropylene at a ratio of 85:15 to 15:85, or any other ratio.
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Kumar in view of Kumar II by carrying out the method of Kumar on a mixture of polyethylene and polypropylene at a ratio of 85:15 to 15:85, in order to obtain a predictably functional method which is congruent the suggestions of Kumar II.
Claim(s) 6 is/are rejected under 35 U.S.C. 103 as being unpatentable over Kumar in view of Yalcin and Aydemir, as applied to claim 5 above, and in further view of Bardin et al. (“Characterization of copper and vanadium containing heteropolyacid catalysts for oxidative dehydrogenation of propane”; https://doi.org/10.1016/S0926-860X(99)00174-X), hereafter referred to as Bardin.
With regard to claim 6: Modified Kumar is silent to the heteropoly acid further comprising additional transition metal compounds, wherein the ratio of W or Mo and the additional transition metal compounds is 0.5-100.
However, at least the disclosure of Aydemir would, to one of ordinary skill in the art, suggest that SBA supported heteropolyacids in general, not just TPA, would be suitable for use as a catalyst in depolymerization reactions. Namely, a person having ordinary skill in the art would take such a suggestion from the following except of Aydemir:
Mesostructured catalysts such as aluminosilicates, mobil composition of matter (MCM)-type and Santa Barbara Amorphous (SBA)-type catalysts on the other hand, have mesopores which allow easier access of the polymeric molecules within the pores of the solid material. However, SBA-15 itself does not show considerable catalytic activity unless appropriate acidic medium is introduced into the structure.1 Therefore, heteropoly acids can be incorporated to the structure for better catalytic activity. Heteropoly acids are selected as acid source because of their highly acidic character. Heteropoly acids could not be used alone as catalysts in cracking reactions due to their low thermal stability and surface area.12 Therefore, they are being used by impregnating into SBA-type silicate catalysts because of high surface area, thermal, and hydrothermal stabilities of these materials.12 There are very few studies in the literature which use heteropoly acids as the solid acid catalysts in polymer cracking reactions.13
(Aydemir: Introduction; emphasis added).
Bardin teaches a heteropolyacid comprising Mo, as well as copper (Cu) and Vanadium (V), both of which are transition metal elements (see whole document, especially abstract, section 2.1, section 3, and Table 1). From the information provided in Table 1, it can be determined that said heteropolyacid has a Mo to Cu and V ratio of 5.22. Thus, Bardin’s teachings show that heteropolyacids comprising Mo and additional transition metal compounds, wherein the ratio of Mo and the additional transition metal compounds is 0.5-100, are known in the art.
Taking the teachings of Aydemir and Bardin in combination, a person having ordinary skill in the art would have a reasonable expectation that it is possible to form a heteropolyacid catalyst comprising Mo, Cu, and V, wherein the ratio of Mo to Cu and V is in the range of 0.5-100. A person having ordinary skill I the art would also have a reasonable expectation that such a catalyst would be functional as a depolymerization catalyst.
Accordingly, it would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Kumar in view of Aydemir and Bardin by using, as the catalyst, a supported heteropolyacid catalyst comprising Mo, Cu, and V, wherein the ratio of Mo to Cu and V is in the range of 0.5-100, based on its predictable suitability for use as a depolymerization catalyst (see MPEP 2143 I.E).
Claim(s) 8, 10, and 11 is/are rejected under 35 U.S.C. 103 as being unpatentable over Kumar in view of Yalcin and Aydemir, as applied to claim 1 above, and in further view of Thomas et al. (“Comparison of H3PW12O40 and H4SiW12O40 heteropolyacids supported on silica by 1H MAS NMR”; https://doi.org/10.1016/j.crci.2005.06.006).
With regard to claims 8, 10, and 11: In modified Kumar, the catalyst comprises a heteropolyacid (TPA) supported by SBA-15 (see rejection of claim 1 above). SBA-15 is a silica material. Therefore, the catalyst comprises a silica supported heteropolyacid.
Modified Kumar is silent to the heteropolyacid being tungstosilicic acid (TSA).
However, at least the disclosure of Aydemir would, to one of ordinary skill in the art, suggest that SBA supported heteropolyacids in general, not just TPA, would be suitable for use as a catalyst in depolymerization reactions. Namely, a person having ordinary skill in the art would take such a suggestion from the following except of Aydemir:
Mesostructured catalysts such as aluminosilicates, mobil composition of matter (MCM)-type and Santa Barbara Amorphous (SBA)-type catalysts on the other hand, have mesopores which allow easier access of the polymeric molecules within the pores of the solid material. However, SBA-15 itself does not show considerable catalytic activity unless appropriate acidic medium is introduced into the structure.1 Therefore, heteropoly acids can be incorporated to the structure for better catalytic activity. Heteropoly acids are selected as acid source because of their highly acidic character. Heteropoly acids could not be used alone as catalysts in cracking reactions due to their low thermal stability and surface area.12 Therefore, they are being used by impregnating into SBA-type silicate catalysts because of high surface area, thermal, and hydrothermal stabilities of these materials.12 There are very few studies in the literature which use heteropoly acids as the solid acid catalysts in polymer cracking reactions.13
(Aydemir: Introduction; emphasis added).
Thomas, which is notably cited as reference 12 in the above excerpt from Aydemir, teaches the production of a silica supported TPA (H3PW12O40) catalyst as well as a silica supported TSA (H4SiW12O40) catalyst (abstract, introduction). Thus, Thomas’ teachings show that TSA is known in the art, as silica supported TSA catalyst. It is reiterated that SBA-15 is a silica material.
Taking the teachings of Aydemir and Thomas in combination, a person having ordinary skill in the art would have a reasonable expectation that it is possible to form a SBA-15 supported TSA catalyst that would be functional as a depolymerization catalyst.
Accordingly, it would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Kumar in view of Aydemir and Thomas by using SBA-15 supported TSA as the catalyst, based on its predictable suitability for use as a depolymerization catalyst (see MPEP 2143 I.E).
Citation of Pertinent Prior Art
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
US 8,664,458 and US 10,000,715 are granted patents corresponding to the Kumar and Kumar II PG pubs relied upon in the 103 rejections above.
Conclusion
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/JONATHAN LUKE PILCHER/Examiner, Art Unit 1772