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 .
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.
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.
Claims 1 and 4 – 15 are rejected under 35 U.S.C. 103 as being unpatentable over WO 2015/082379 to Wang et al. (hereinafter referred to as Wang) in view US Patent Application Publication No. 2017/0121875 to Schultz et al. (hereinafter referred to as Schultz).
In regard to claim 1, as discussed in page 1 lines 4 – 9, Wang discloses a melt-blown web made from a polypropylene composition. As discussed in page 2 lines 4 – 11, the polypropylene composition includes a propylene homopolymer that has a melt flow rate (MFR2) and melting temperature that overlap with the claimed ranges. Further, as discussed in page 3 lines 2 – 6, the propylene homopolymer can have a content of 2,1 erythro defects that overlaps with the claimed range. The subject matter as a whole would have been obvious to one having ordinary skill in the art at the time the invention was made to have selected the overlapping portion of the range disclosed by the reference because overlapping ranges have been held to be a prima facie case of obviousness, see In re Malagari, 182 U.S.P.Q. 549; In re Wertheim 191 USPQ 90 (CCPA 1976).
As discussed in page 15 lines 19 – 28, the melt-blown web can be used as a filtration medium. Wang, however, does not disclose an electret melt-blown web. Schultz discloses an electret web. As discussed in paragraphs [0001] – [0003] and [0036] of Schultz, electret webs are well known to be used as filtration media and provide for improved performance in different filter applications. As discussed in paragraph [0022], polypropylene is known to be a material that can be used to form an electret web. Thus, one of ordinary skill in the art would reasonably expect the melt-blown web of Wang made from a polypropylene composition could be formed as an electret web.
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Wang to form the web as an electret web as suggested by Schultz in order to enhance the filtration properties of the web when used in filtration applications.
In regard to claims 4 – 6, as discussed in page 6 of Wang, the propylene homopolymer can be formed by visbreaking a precursor propylene homopolymer. The visbreaking ratio and the MFR2 of the precursor propylene polymer can overlap with the claimed ranges. The subject matter as a whole would have been obvious to one having ordinary skill in the art at the time the invention was made to have selected the overlapping portion of the range disclosed by the reference because overlapping ranges have been held to be a prima facie case of obviousness, see In re Malagari, 182 U.S.P.Q. 549; In re Wertheim 191 USPQ 90 (CCPA 1976).
In regard to claims 7 and 8, how the propylene homopolymer is polymerized relates to the method of making the web. The electret melt-blown web of Wang and Schultz is considered to have the same structure as a web where the propylene homopolymer is polymerized as described in claims 7 and 8.
In regard to claims 9 and 10, Schultz is used as the secondary reference disclosing the electret web. As discussed in paragraphs [0029] and [0030], Schultz discloses using a charge-enhancing additive that includes a hindered amine. The charge-enhancing additive can also be considered a charge-stabilizing agent. Schultz discloses using the additive in range that falls within the claimed range in claim 9 of the present application. It would further have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Wang and Schultz to include a charge-stabilizing agent including a hindered amine in an amount from 0.005 to 5.0 wt.% based in the total weight of the composition as suggested by Schultz in order to provide a more effective electret web.
In regard to claims 11 – 13, the electret melt-blown web of the combination of Wang and Schultz includes all of the required structural features and inherently is considered to have the properties recited in claims 11 – 13. These claims do not require any further structural limitations.
In regard to claim 14, the electret melt-blown web of the combination of Wang and Schultz inherently is formed by the steps of providing a propylene homopolymer or a precursor homopolymer, pelletizing either the precursor propylene homopolymer or the propylene homopolymer to obtain the polypropylene composition, melt-blowing the pellets, and electrostatically charging the melt-blown web to obtain an electret melt-blown web.
In regard to claim 15, as discussed in paragraph [0003] of Schultz, corona charging, tribocharging, and hydro-charging can all be used to form the electret web.
Claims 2 and 3 are rejected under 35 U.S.C. 103 as being unpatentable over Wang and Schultz as applied to claim 1 above, and further in view of US Patent Application Publication No. 2019/0301055 to Wang et al. (hereinafter referred to as Wang ‘055).
The combination of Wang and Schultz is discussed above in section 4. Wang is used as the primary reference disclosing the polypropylene composition. Wang does not specifically disclose the molecular weight distribution or the weight average molecular weight for the propylene homopolymer. Wang ‘055 discloses a similar melt-blown web made from two polypropylenes. As discussed in paragraphs [0019], [0020], [0077], the molecular weight distribution of both the polypropylenes and the mixture overlaps with the claimed range. Similarly, as discussed in paragraphs [0009], [0012], and [0075], the weight average molecular weight overlaps with the claimed range. One of ordinary skill in the art would reasonably expect a single propylene homopolymer having a molecular weight distribution and weight average molecular weight in these ranges could similar to be formed into a melt-blown web.
Thus, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Wang and Schultz to use a propylene homopolymer having a molecular weight distribution in the range from 1.0 to 5.0 and weight average molecular weight in the range from 25,000 to 85,000 as suggested by Wang ’055 as a propylene composition with these properties is known to be useful for forming melt-blown webs.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
Other prior art references listed on the PTO-892 (Notice of References Cited) are considered to be of interest disclosing similar non-woven webs.
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/ROBERT CLEMENTE/Primary Examiner, Art Unit 1773