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 .
Information Disclosure Statement
The information disclosure statement (IDS) submitted on 02 July 2025 is in compliance with 37 CFR 1.97, 1.98, and have/has been considered.
Election/Restrictions
Applicant’s election without traverse of Group 1: claims 1-13 in the reply filed on 17 August 2026 is acknowledged. Claims 14-17 are withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to a nonelected invention, there being no allowable generic or linking claim.
Examiner’s Note
It is noted that all references hereinafter to Applicant’s specification are to the published application US 20240178520 A1 unless otherwise stated. Additionally, any italicized, bolded, or underlined text utilized hereinafter is to be interpreted as emphasis placed thereupon.
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 1-3, 5-10, and 12 are rejected under 35 U.S.C. 103 as being unpatentable over He et al. (CN 107611320 A, provided by IDS on 02 July 2025, machine translation used hereafter, “He”) in view of Kim et al. (KR 20190092876 A, machine translation used hereafter, “Kim”).
Regarding Claims 1 and 10, He discloses a coating for a lithium-ion battery separator (i.e. a secondary battery separator, [0018]) wherein the coating is formed from an aqueous slurry composed of cellulose microfibers, cellulose nanofibers, cellulose nanocrystals, or a combination thereof (i.e. a cellulose coating layer containing cellulose nanofibers and cellulose nanocrystals, [0015] and [0033]) and is disposed on one or both sides of a polyolefin-based film (i.e. one surface or both surfaces of a support, [0023]-[0025]). The polyolefin-based film is a polyethylene-based film, a polypropylene-based film, or a combination thereof (i.e. the porous support comprises any one selected from the group consisting of high-density polyethylene, low-density polyethylene, linear low-density polyethylene, ultrahigh- molecular weight polyethylene, polypropylene, polybutylene, polypentene, polypropylenepolyethylene terephthalate, polybutylene terephthalate, polyester, polyacetal, polyamide, polycarbonate, polyimide, polyetheretherketone, polyethersulfone, polyphenylene oxide, polyphenylene sulfide and polyethylene naphthalene, or a combination of two or more of them; overlapping limitations are bolded for clarity, [0024]).
He however is silent regarding the coating layer as comprising a continuous phase formed from a plurality of cellulose nanofibers having a chain entanglement structure and a dispersed phase formed from the cellulose nanocrystals. He is further silent regarding the support as being porous. As mentioned above, He discloses a polyolefin support but does not explicitly disclose the polyolefin support as being porous. The background of He states, “polyethylene or polypropylene is extruded into a film using wet or dry processes, and then stretched to create nanopores that allow lithium ions to migrate through” ([0004]). It would have been obvious to one having ordinary skill in the art at the time the invention was made to apply a porous coating to a porous support for use within a battery, since it has been held to be within the general skill of a worker in the art to select a known material on the basis of its suitability for the intended use as a matter of obvious engineering choice. In re Leshin, 125 USPQ 416.
Furthermore, it is understood that polyolefin supports are by nature microporous to nanoporous, and it stands to reason that He invented a porous nanocellulose coating to apply to a porous support, as otherwise applying a porous coating to a nonporous support is unreasonable. Where the Patent Office has reason to believe that a functional limitation asserted to be critical for establishing novelty in the claimed subject matter may, in fact, be an inherent characteristic of the prior art, it possesses the authority to require applicant to prove that the subject matter shown to be in the prior art does not possess the characteristic relied upon. In re Swinehart, 439 F.2d 210, 169 USPQ 226 (CCPA 1971). See MPEP 2144.03. Kim discloses a coating composition comprising cellulose nanofibers and nanocrystals ([0034]) where the cellulose nanocrystals with a relatively small particle size are positioned in the interlocking chain structure gaps between the cellulose nanofibers (i.e. a continuous phase formed from a plurality of cellulose nanofibers having a chain entanglement structure and a dispersed phase formed from the cellulose nanocrystals, [0048]).
He and Kim each constitute prior art which is directly analogous to the claimed invention: nanocellulose coatings. Therefore, in view of the combined teachings of the prior art, it would have been obvious to a person of ordinary skill in the art prior to the effective filing date of the claimed invention to include cellulose nanocrystals within the cellulose nanofiber network, as Kim shows that the oxygen permeability was improved, and thus having improved gas barrier properties ([0080} of Kim), since it has been held to be within the general skill of a worker in the art to select a known material on the basis of its suitability for the intended use as a matter of obvious engineering choice. In re Leshin, 125 USPQ 416. Regarding Claim 2, He discloses that the slurry used to form the coating has a cellulose nanofiber content of 1% and a cellulose nanocrystal content of 0.5% (i.e. the cellulose nanocrystals are present in an amount of 1-200 parts by weight based on 100 parts by weight of the cellulose nanofibers, [0090]). As this is a 2:1 relationship of cellulose nanofibers to nanocrystals, it can be found that 0.5% (the content of the cellulose nanocrystal) is 100 parts by weight and 1% (the content of the cellulose nanofiber) is 200 parts by weight.
Regarding Claim 3, He discloses that the cellulose nanofibers have a width of less than 200 nm (i.e. the cellulose nanofibers have an average diameter of 50-500 nm on the longitudinal section thereof, [0076]). In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976). See MPEP 2144.05.
Regarding Claims 5 and 6, He discloses that the cellulose nanocrystals have a width of less than 10 nm (i.e. the cellulose nanocrystals have an average diameter of 1-50 nm on the longitudinal section thereof, [0076]). The aspect ratio can be calculated by dividing the longest dimension (i.e. the length which is greater than 200 nm, [0076]) by the shortest dimension (i.e. the width, which is less than 10 nm, [0076]. Taking two embodiments within those ranges where the length is 250 nm and the width is 5 nm, the aspect ratio is calculated to be 50 (i.e. the cellulose nanocrystals have an average aspect ratio of 10-1000; 250 divided by 5 =50, [0076]).
In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976). See MPEP 2144.05. Regarding Claim 7, He discloses that the cellulose coating layer, as discussed above, is prepared by forming a water-based slurry of the nanocellulose fibers and crystals along with common solvents such as N-Methyl-2-pyrrolidone (NMP), which has a boiling point of 202-204°C (i.e. the cellulose coating layer is prepared from a cellulose coating composition comprising: cellulose nanofibers; cellulose nanocrystals; and a mixed solvent of water with an organic solvent having a higher boiling point than the boiling point of water, see [0042]-[0044] and [0048]).
Furthermore, He discloses the cellulose coating later as described above in the analysis of claim 1, and while the claim includes the product-by-process limitation wherein the cellulose coating layer is prepared from a cellulose coating composition, patentability is based on the product itself. "[E]ven though product-by-process claims are limited by and defined by the process, determination of patentability is based on the product itself. The patentability of a product does not depend on its method of production. If the product in the product-by-process claim is the same as or obvious from a product of the prior art, the claim is unpatentable even though the prior product was made by a different process." In re Thorpe, 777 F.2d 695, 698, 227 USPQ 964, 966 (Fed. Cir. 1985). See MPEP 2113.
Regarding Claim 8, The coating of He has a thickness ranging from 0.2 to 10 micrometers (i.e. the cellulose coating layer has a thickness of 1-10 µm, [0060]).
Regarding Claim 9, He discloses an aqueous slurry as containing various polymer nanospheres, metal oxides and metal hydroxides, such as alumina, boehmite, magnesium oxide, calcium oxide, silicon oxide, diatomaceous earth, titanium oxide, calcium sulfate, barium sulfate and calcium carbonate. It also includes additives such as fluorinated resins such as polyacrylic acid and its copolymers, polyacrylates and their copolymers, polyvinyl alcohol and its copolymers, polyvinylpyrrolidone and its copolymers, carboxymethyl cellulose and its derivatives, polyvinylidene fluoride, polytetrafluoroethylene, and polyvinylidene fluoride copolymers; or polymers such as polyimide, polyamide, polysulfone, and acrylonitrile polymers (i.e. the cellulose coating layer further comprises at least one selected from a dispersant and inorganic particles, [0016], [0046], and [0047]). He additionally discloses that by selecting cellulose nanofibers and cellulose nanocrystals of different lengths and diameters, and by adjusting the cellulose content, the type and size range of fillers, and the variety and content of known additives, the resulting slurry can effectively prevent the fillers from self-aggregating and precipitating (i.e. the role of a dispersant, [0056]).
Regarding Claim 12, He discloses that the battery separator supplied with the coating, as detailed above (see analysis for claim 1), has a puncture strength of 525 gram-force (gf) (see translated table of He below, where the right-most column details the puncture strength, and example 5, which corresponds to the coating layer as detailed above; translation provided by Google translate).
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Table 1 of He, annotated by the examiner and translated using Google translate
A puncture strength of 525gf corresponds to a puncture strength of 5.148 N (i.e. a puncture strength of 5 N or more; gf is converted to Newtons by multiplying 525 by 0.009807, see table above).
In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976). See MPEP 2144.05.
Claim 13 is rejected under 35 U.S.C. 103 as being unpatentable over He et al. in view of Kim et al., as applied to claims 1-3, 5-10, and 12 above, and further in view of Official Notice.
Regarding Claim 13, He does not explicitly disclose the use of the separator with a secondary battery, however it is common knowledge to one of ordinary skill in the art that a separator is a necessary component of a secondary battery, as implied by the phrase “secondary battery separator” present in claims 1 and 13. As such, it would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to use the secondary battery separator within a secondary battery, as the motivation need not be found in the references sought to be combined, but may be found in any number of sources, including common knowledge, the prior art as a whole, or the nature of the problem itself. In re Dembiczak, 175 F.3d 994, 999 (Fed. Cir. 1999). As we explained in Motorola, Inc. v. Interdigital Tech. Corp., 121 F.3d 1461, 1472 (Fed. Cir. 1997), "there is no requirement that the prior art contain an express suggestion to combine known elements to achieve the claimed invention. Rather, the suggestion to combine may come from the prior art, as filtered through the knowledge of one skilled in the art." See MPEP 2144.03.
Furthermore, the phrase “secondary battery separator” necessarily implies its use within a secondary battery. It has been held that a recitation with respect to the manner in which a claimed apparatus is intended to be employed does not differentiate the claimed apparatus from a prior art apparatus satisfying the claimed structural limitations (Ex Parte Masham, 2 USPQ2d 1647 (1987).
Claims 4 and 11 are rejected under 35 U.S.C. 103 as being unpatentable over He in view of Kim, as applied to claims 1, 2, 7-10, and 12 above, and further in view of Park et al. (US 2019237731 A1, “Park”). Regarding Claim 4, He in view of Kim does not disclose the cellulose nanofibers as having an average aspect ratio of 50-3000.
Park discloses a nanocellulose coating for a porous separator comprising small-diameter cellulose nanofibers (i.e. cellulose nanofibers, [0008] and [0040]) wherein the aspect ratio of the small-diameter cellulose nanofibers ranges from 10-100 or greater (i.e. the cellulose nanofibers have an average aspect ratio of 50-3000, [0040]).
He, Kim, and Park each constitute prior art which is directly analogous to the claimed invention: nanocellulose coatings for porous separators. Therefore, in view of the combined teachings of the prior art, it would have been obvious to a person of ordinary skill in the art prior to the effective filing date of the claimed invention to use the small-diameter fibers of Park within the coating slurry of He, as the small-diameter fibers may have improved binding strength therebetween, and thus, the porous film may have improved mechanical properties ([0040] of Park). Furthermore, in the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976). See MPEP 2144.05.
Regarding Claim 11, He in view of Kim is silent regarding the secondary battery separator as having an air permeability (Gurley value) of 600 s/100 cc air or less. Park discloses nano-cellulose coated porous separator as discussed above, wherein the porous film has an air permeability (Gurley value) per unit thickness of 30 sec/100 cc·μm or less ([0028]). As this is reported in a value of unit per thickness, converting to the air permeability value simply requires multiplying 30 sec/100 cc cc·μm by the thickness of the film. The thickness of the film of He is 0.2 to 10 micrometers, which is established within the analysis of claim 8 above. Multiplying 30 sec/100 cc cc·μm by the endpoints of the range of the film gives Gurley value range of 6 s/100 cc to 300 s/100 cc (i.e. an air permeability (Gurley value) of 600 s/100 cc air or less, [0028], see further air permeability ranges of Park in [0030]). He, Kim, and Park each constitute prior art which is directly analogous to the claimed invention: nanocellulose coatings for porous separators. Therefore, in view of the combined teachings of the prior art, it would have been obvious to a person of ordinary skill in the art prior to the effective filing date of the claimed invention to seek a material with similar Gurley value, as when the Gurley value is too low, lithium may easily precipitate in pores of the porous film. Accordingly, when a porous film having an excessively low Gurley value is used as a separator in a lithium battery, a short circuit caused by lithium dendrites is more likely to occur due to poor lithium blocking characteristics of the separator. On the other hand, when the Gurley value is too high, migration of lithium ions through the porous film may be hindered. Accordingly, when a porous film having an excessively high Gurley value is used as a separator in a lithium battery, cycle characteristics of the lithium battery may be deteriorated due to increased internal resistance of the lithium battery ([0030] of Park).
Bearing in mind the deleterious effects of too low or high a Gurley value as discussed above, the claimed range is a result of optimizing to negate the undesired effects, and as such, it has been held that the discovery of the optimum value of a result effective variable in a known process is ordinarily within the skill in the art. In re Boesch and Slaney, 205 USPQ 215 (CCPA 1980). Furthermore, in the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976). See MPEP 2144.05.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to MICHAEL P MALONEY whose telephone number is (571)270-1730. The examiner can normally be reached M-Th: 7:30a-5p, F: 7:30a-4p.
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/MICHAEL PATRICK MALONEY/Examiner, Art Unit 1782
/AARON AUSTIN/Supervisory Patent Examiner, Art Unit 1782
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