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 .
Claim Objections
Claim 1 and the claims dependent therefrom are objected to because the limitation defining the sum of a, b, and c, as being as low as 5 and the limitation defining the content of low molecular weight siloxanes appear to be in conflict. Indeed, it would seem that the majority of the polymer chains would have a weight-average molecular weight less than 700 where the average sum of a, b, and c, is at the low end of the given range.
Claim Rejections - 35 USC § 102
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
Claim 1 is rejected under 35 U.S.C. 102(a)(1) as being anticipated by Matsumoto et al., U.S. Patent Application Publication No. 2020/0079803.
Applicant is directed to Example 6 where there is described a stepwise synthesis of an oligomer bearing a plurality of diphenylsiloxane units, but where none of said units are adjacent to one another. The product, isolated in 44% yield has between 5 and 500 repeat units and is anticipatory of formula 1 where one of each of the terminal R1 groups is an isopropoxy group and the remaining R groups are either methyl or ethyl. The polymer is prepared by alternatingly adding to the reaction mixture acetone to convert the hydrosilyl group-terminated chain to an alkoxy-terminated chain followed by the introduction of an equivalent of a dialkylsilane. The alkoxysilyl-terminated oligomer and dialkylsilane participate in a Piers-Rubinsztajn reaction. The resulting product is, once more, hydrosilyl group-terminated thus enabling the same sequence to be performed until a product of preferred degree of polymerization/molecular weight is obtained. Given that (i) the product mixture undergoes a purification process and (ii) insofar as the Piers-Rubinsztajn reaction is highly selective and the polymerization system is devoid of any components that can lend to side reactions, the product will inherently satisfy the limitation defining the oligomer content with a Mw less than 700 amu.
Claim 1 is rejected under 35 U.S.C. 102(a)(1) as being anticipated by the article entitled “Acid and Base-catalyzed Ring-opening Polymerization of 2,2,4,4,6,6-hexamethyl-8,8-diphenylcyclotetrasiloxane” authored by Teng et al. and published in Polymer (2003) 44, 4149-4155.
Applicant is directed to the abstract, Figure 2, and the subject matter under the heading 2.7.7 Cationic Polymerization of 1. (Copoly(dimethylsiloxane/diphenylsiloxane) (3:1 mol ratio) where there is described the initial polymerization of 2,2,4,4,6,6-hexamethyl-8,8-diphenylcyclotetrasiloxane in the presence of triflic acid followed by endcapping with hexamethyldisilazane so that groups R13SiO1/2, R = methyl, are introduced at the terminal positions. The resulting number-average molecular weight and weight-average molecular weight are 12,230 and 23,500 respectively consistent with a polymer that has fewer than 500 repeat units.
As for the limitations of the final 4 lines of claim 1, the subject matter in the abstract, Figure 2, and under the heading 4.1 Microstructure analysis by 29Si NMR spectroscopy of triflic acid-catalyzed ROP of I, indicates that the ring oxygen atoms of the cyclosiloxane precursor between two Me2Si residues generate a substantially more stable oxonium ion relative to the ring oxygen atoms flanked on one side with Ph2Si and, thus, bond-breaking/ring-opening occurs at those positions thus guaranteeing that the lone Ph2Si group will always end up in the interior of the 4 silicon atom siloxane chain as is depicted in Figure 2 and, therefore, there will rarely be formed -Ph2Si-O-SiPh2- diads. The reference is less forthcoming as to the amount of low molecular weight siloxane content but the background section indicates that triflic acid-catalyzed processes are not susceptible to randomization-causing backbiting or intermolecular exchange. Moreover, the reaction conditions mirror those outlined in the instant Specification in terms of similar cyclosiloxane starting materials being subject to cationic ring-opening polymerization promoted by triflic acid. The temperature at which the polymerization was carried out is not expressly disclosed, in which case it may be presumed that the reaction was performed at ambient temperature (within the range set forth in claims 4 and 5). Given that the monomers, catalyst, and conditions are all the same, a skilled practitioner may reasonably expect that the prior art polymer will inherently conform with the stated low molecular siloxane content.
Claim Rejections - 35 USC § 103
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.
Claims 2-5 are rejected under 35 U.S.C. 103 as being unpatentable over the article entitled “Acid and Base-catalyzed Ring-opening Polymerization of 2,2,4,4,6,6-hexamethyl-8,8-diphenylcyclotetrasiloxane” authored by Teng et al. and published in Polymer (2003) 44, 4149-4155 in view of Drake et al., WO 2013/086025.
One distinction between the synthetic approach of the claims and that summarized under the heading 2.7.7 Cationic Polymerization of 1. (Copoly(dimethylsiloxane/diphenylsiloxane) (3:1 mol ratio) is that the former employs a hexaorganodisiloxane compound as and endcapper whereas hexadimethylsilazane is used in this capacity in the reference.
Drake teaches the formation of polysiloxanes useful in the practice of their invention from cyclosiloxanes [0015+]. The cyclosiloxanes may be polymerized under anionic or cationic conditions alike with a strongly overlapping list of suitable protic acids to that set forth on page 5 of the instant Specification being delineated in [0016]. A discussion of chain terminating agents follows at [0027+] and [0029] outlines several different candidates including hexamethyldisiloxane and hexamethyldisilazane thus suggesting their equivalency. Further, the utilization of hexamethydisilazane in this context leads to ammonia formation as a by-product, which of course is corrosive. Hence, the substitution of hexamethyldisiloxane for hexadimethylsilazane would have been obvious to one of ordinary skill as of the effective filing date of the instant invention.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to MARC S ZIMMER whose telephone number is (571)272-1096. The examiner can normally be reached M-F 8:30-5:00.
Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Heidi Kelley can be reached at 571-270-1831. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000.
July 8, 2026
/MARC S ZIMMER/Primary Patent Examiner, Art Unit 1765
Prosecution Insights