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 IDS filed 5/5/2026 has been considered bye examiner.
Response to Amendment
The Amendment filed on 3/18/2026 has been entered. Claims 6-8 are cancelled. Claims 1-5 and 9-14 remain pending in the application.
Claim Objections
Claim 1 is objected to because of the following informalities: Claim 1 is not written concisely [see MPEP(T)(Article 6)]. Examiner proposes the following claim language to correct this issue:
A method for manufacturing a separator for a lithium secondary battery, comprising the steps of:
preparing a slurry for forming a porous coating layer comprising inorganic particles dispersed in an asymmetric linear ketone solvent and a binder polymer, comprising a first binder polymer and a second binder polymer, dissolved therein; and
applying the slurry for forming the porous coating layer onto a porous polymer substrate having a plurality of pores, followed by drying,
wherein the first binder polymer comprises a thermoplastic polyurethane comprising a soft segment having a polyol-derived repeating unit and a hard segment having a urethane binding structure,
wherein the second binder polymer comprises polymethyl methacrylate
wherein the first binder polymer is present in an amount larger than 10 parts by weight based on 100 parts by weight of a total content of the binder polymer,
wherein asymmetric linear ketone solvent comprises methyl ethyl ketone, and
wherein the first binder polymer and the second binder polymer are introduced into the solvent at a weight ratio in a range of 90:10 to 30:70.
Applicant is advised that should claim 3 be found allowable, claim 11 will be objected to under 37 CFR 1.75 as being a substantial duplicate thereof. When two claims in an application are duplicates or else are so close in content that they both cover the same thing, despite a slight difference in wording, it is proper after allowing one claim to object to the other as being a substantial duplicate of the allowed claim. See MPEP § 608.01(m).
Claim Rejections - 35 USC § 112
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.
Claim 1 and dependent claims 2-5 and 9-14 are 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 limitations "the second binder" and “the solvent” in line 15. There is insufficient antecedent basis for these limitations in the claim.
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 text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claims 1, 3-5, 10-11, and 13-14 are rejected under 35 U.S.C. 103 as being unpatentable over Wu et al. (US 2013/0327704, hereinafter "Wu") in view of Kwon et al. (KR 20190056157, making reference to previously provided English translation thereof, hereinafter “Kwon”) and Maruoka et al. (JP 2016134247, making reference to previously provided English translation thereof, hereinafter “Maruoka”).
Regarding claim 1, Wu teaches a method of manufacturing an electrochemical separation membrane (“separator”) for a lithium secondary battery [Abstract, “An electrochemical separation membrane and the manufacturing method thereof are disclosed”, 0005, “With the technology of the battery design and materials in existence and the development of new materials, the application fields of the secondary lithium ion battery are broadened”]. Wu teaches that the method comprises the steps of:
Preparing a polymer solution (“slurry”) for forming a polymer gel (“porous coating layer”) comprising ceramic precursors (“inorganic particles”) dispersed in an asymmetric linear ketone solvent such as butanone (otherwise known as methyl ethyl ketone) and a polymer material (“binder polymer”) dissolved therein [0030, “The polymer solution preparing step S11 is to mix at least one polymer material, at least one solvent and at least one ceramic precursor thoroughly, such that the polymer material and the ceramic precursor dissolve uniformly in the solvent”, “The polymer material becomes a polymer gel … and the ions not only move free in the continuous micro holes”, 0032, “ The solvent is selected from the group consisting of at least one of acetone, butanone … acetone and butanone with high vaporization and low boiling points are preferred for forming the porous polymer membrane”, 0040, “A porous ceramic-polymer composite membrane which can be used to an electrochemical separation membrane is obtained after drying”]; and
coating the polymer solution onto a porous base material having a plurality of pores (“porous polymer substrate”) [0034, “The coating step S13 is to coat the polymer solution on a porous base material, 0028, “The porous base material 10 is a polyolenfine cellulose material”], followed by drying [0038, “The drying step S17 is to remove the water and solvent from the porous base material”]; wherein
wherein the polymer material may comprise polyurethane (“first binder polymer”) and polymethyl methacrylate (“second binder polymer/acrylate-containing polymer”) [0031, “The polymer material is selected from the group consisting of at least one of … polyurethane … polymethyl methacrylate”].
Wu is silent regarding the first binder polymer being a thermoplastic polymer comprising a soft segment having a polyol-derived structure and the second binder polymer having a glass transition temperature of 25°C to 125°C.
Kwon teaches analogous art of a method of manufacturing a separator for a secondary battery [0001]. Kwon teaches a porous coating membrane for a separator, the porous coating membrane including a multiphase polymer [0007, “a porous coating membrane containing a multiphase polymer”] such as polyurethane or polymethyl methacrylate [0017, “The multiphase polymer may be one or more selected from, for example, a polymethyl methacrylate-polybutylene methacrylate copolymer, a fish oil polymer, a soybean oil-styrene-divinylbenzene copolymer, and a shape memory polyurethane”]. Kwon teaches that the multiphase polymer comprises a hard segment and a soft segment [0007, “multi-phase polymer including a hard segment and a soft segment”]. The soft segment is derived from a polyol unit [0028, “The soft segment is a unit derived from a polyol”], and the hard segment has urethane bonds (“urethane binding structure”) [0029, “The hard segment forms a rigid crystal lattice through strong hydrogen bonds between urethane bonds”]. While Kwon does not explicitly say that the polyurethane is a thermoplastic polyurethane, the “shutdown” function of the disclosed separator wherein the separator melts to shutdown pores when the battery is overheated [0015] would require a thermoplastic polymer. Kwon also discloses that the multiphase polymers, which include an acrylate-containing polymer, have a glass transition temperature of around 100°C [0017].
Kwon discloses that including a polymer with a hard and soft segment in the separator imparts a shutdown function to the separator during overheating while also preventing the separator from losing its shape completely, preventing ignition or explosion of the battery [0015]. Kwon also discloses that the glass transition temperature of the polymer contributes to the shutdown function, which enhances the heat safety of the battery [0096, “By using the glass transition temperature of a membrane manufactured by incorporating a porous coating membrane containing a multiphase polymer into a high-heat-resistant nonwoven fabric, it is possible to secure a shutdown function”, “Therefore, these composite separators greatly enhance the heat safety of large-capacity or high-capacity secondary batteries”].
Therefore, it would have been obvious to a person having ordinary skill in the art prior to the effective filing date of the claimed invention to have modified the polyurethane and acrylate-containing polymers taught by Wu to include a hard and soft segments and a glass transition temperature as taught by Kwon, in order to impart a shutdown function on the battery, therefore improving the safety of the battery and preventing ignition or explosion.
Wu is silent regarding the amount of the first binder polymer based on the total content of the binder polymer and the weight ratio of the first binder polymer to the second binder polymer.
Maruoka teaches analogous art of a coating material for a secondary battery separator [0001]. Maruoka teaches that the coating material includes an acid-modified polyolefin resin (A) (“second binder polymer”) and a polyurethane resin (B) (“first binder polymer”) [0012], the acid-modified polyolefin resin including a (meth)acrylic acid ester [0024, “The acid-modified polyolefin resin may contain a (meth)acrylic acid ester”]. Maruoka teaches that the weight ratio of (A) to (B) is preferably 70:30 to 55:45, meaning that the weight ratio of (B) to (A) is 45:55 to 30:70, which is within the recited range [0042, “The mass ratio (A)/(B) of the acid-modified polyolefin resin (A) to the polyurethane resin (B) … most preferably 70 /30 to 55/45”]. Furthermore, the polyurethane resin (B) would be present in an amount of 30 parts by weight to 45 parts by weight based on 100 parts by weight of the total content of the binder polymer, which is within the recited range.
Maruoka teaches that if the amount of polyurethane (B) is too small, the adhesive quality, dimensional stability at high temperature, and permeability of the separator will all decrease, resulting in worsened battery characteristics [0044].
Therefore, it would have been obvious to a person having ordinary skill in the art prior to the effective filing date of the claimed invention to have modified the method of manufacturing the separator taught by Wu to include the first binder polymer in the amount taught by Maruoka, in order to prevent a decrease in battery characteristics.
Regarding claim 3, Wu as modified by Kwon teaches a thermoplastic polymer having a hard and soft segment.
Kwon teaches that the in the multiphase polymer, the soft segment is a unit derived from a polyol, while the hard segment is a unit derived from a semi-crystalline aromatic diisocyanate [0028]. Kwon further teaches that the molar ratio of diisocyanate to polyol, or hard segment to soft segment, is 1.1:1 to 5:1 [0042, “The content of the above-mentioned difunctional aromatic diisocyanate is 1.1 to 5.0 mol based on 1 mol of the difunctional polyol”], which is within the claimed range.
Kwon teaches that within that range, the amount of hard segment, or fixed phase, is larger than the amount of soft segment, or reversible phase [0042, “When the content of the bifunctional aromatic diisocyanate, polyol, and chain stabilizer is within the above range, a polyurethane having a higher content of the fixed phase than that of the reversible phase can be produced”]. Kwon teaches that when the fixed phase content is greater than the reversible phase content, the thermal and mechanical stability characteristics are excellent [0018].
Therefore, it would have been obvious to a person having ordinary skill in the art to modify the method taught by modified Wu to include a molar ratio of the hard segment to the soft segment as taught by Kwon, in order for the separator to have excellent thermal and mechanical stability characteristics.
Furthermore, it would have been obvious to one having ordinary skill in the art at the effective filing date of the invention to additionally determine the optimum or workable amounts of the hard and soft segments in order to achieve the desired thermal and mechanical stability characteristics [0018] given, ““[W]here 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.” In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955)”; MPEP 2144.05. See also the following case law:
“The normal desire of scientists or artisans to improve upon what is already generally known provides the motivation to determine where in a disclosed set of percentage ranges is the optimum combination of percentages.” In re Peterson, 315 F.3d at 1330, 65 USPQ2d at 1382.
Claimed elastomeric polyurethanes which fell within the broad scope of the references were held to be unpatentable thereover because, among other reasons, there was no evidence of the criticality of the claimed ranges of molecular weight or molar proportions. In re Hoeschele, 406 F.2d 1403, 160 USPQ 809 (CCPA 1969).
The discovery of an optimum value of a known result effective variable, without producing any new or unexpected results, is within the ambit of a person of ordinary skill in the art. See In re Boesch, 205 USPQ 215 (CCPA 1980) (see MPEP § 2144.05, II.).
Regarding claim 4, Wu is silent regarding the weight average molecular weight of the first binder polymer.
Maruoka teaches that the weight average molecular weight of the polyurethane resin is preferably 50,000 to 500,000, which lies within the claimed range [0040, “The weight average molecular weight of the polyurethane resin is preferably 50,000 to 500,000”].
Maruoka teaches that the weight average molecular weight is preferably within this range to further improve the adhesion between the non-conductive (“inorganic”) particles and the porous substrate [0040, “from the viewpoint of further improving the adhesion between the non-conductive particles and between the non-conductive particles and the porous substrate in the separator”].
Therefore, it would have been obvious to a person having ordinary skill in the art to modify the method taught by modified Wu to have the weight average molecular weight of the first binder polymer to be within the range taught by Maruoka, in order to improve the adhesion between the inorganic particles and porous substrate in the separator.
Regarding claim 5, Wu is silent regarding the weight average molecular weight of the second binder polymer.
Maruoka teaches that the weight average molecular weight of the acid-modified polyolefin resin, which may contain a may contain a (meth)acrylic acid ester, is preferably 20,000 to 150,000, which lies within the claimed range [0027, “the weight-average molecular weight of the acid-modified
polyolefin resin is preferably 20,000 or more, more preferably 20,000 to 150,000”].
Maruoka teaches that the weight average molecular weight is preferably within this range to further improve the adhesion between the non-conductive (“inorganic”) particles and the porous substrate [0027, “From the viewpoint of further improving the adhesion between the non-conductive particles and between the non-conductive particles and the porous substrate in the separator”].
Therefore, it would have been obvious to a person having ordinary skill in the art to modify the method taught by modified Wu to have the weight average molecular weight of the second binder polymer to be within the range taught by Maruoka, in order to improve the adhesion between the inorganic particles and porous substrate in the separator.
Regarding claim 10, Wu is silent regarding the weight ratio of the inorganic particles to a total content of the binder polymer.
Maruoka teaches a weight ratio of the total content of the binder polymer to the non-conductive particles (“inorganic particles”) of 70:30 to 1:99, or a weight ratio of non-conductive particles to the total content of the binder polymer of 30:70 to 99:1, which overlaps with the claimed range [0077, “the blending ratio of the separator coating material to the non-conductive particles in the separator-forming slurry is preferably such that the content mass ratio of the total content of the acid-modified polyolefin resin (A) and the polyurethane resin (B) in the coating material to the content of the non-conductive particles is 70/30 to 1/99”]. In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists (see MPEP 2144.05 I).
Maruoka teaches that the weight ratio of non-conductive particles to binder polymer is preferably within this range in order to improve air permeability, heat resistance, adhesion between the particles and the porous substrate, and penetration in the separator [0077, “From the viewpoint of further improving the air permeability, heat resistance, and adhesion between the porous substrate and the non-conductive particles, and further improving the penetration”].
Therefore, it would have been obvious to a person having ordinary skill in the art to modify the method taught by modified Wu to have a weight ratio of inorganic particles to a total content of the binder polymer in the range taught by Maruoka, in order to improve air permeability, heat resistance, adhesion between the inorganic particles and porous substrate, and penetration in the separator.
Regarding claim 11, Wu as modified by Kwon teaches a thermoplastic polymer having a hard and soft segment.
Kwon teaches that in the multiphase polymer, the soft segment is a unit derived from a polyol, while the hard segment is a unit derived from a semi-crystalline aromatic diisocyanate [0028]. Kwon further teaches that the molar ratio of diisocyanate to polyol, or hard segment to soft segment, is 1.1:1 to 5:1 [0042, “The content of the above-mentioned difunctional aromatic diisocyanate is 1.1 to 5.0 mol based on 1 mol of the difunctional polyol”], which is within the claimed range.
Kwon teaches that within that range, the amount of hard segment, or fixed phase, is larger than the amount of soft segment, or reversible phase [0042, “When the content of the bifunctional aromatic diisocyanate, polyol, and chain stabilizer is within the above range, a polyurethane having a higher content of the fixed phase than that of the reversible phase can be produced”]. Kwon teaches that when the fixed phase content is greater than the reversible phase content, the thermal and mechanical stability characteristics are excellent [0018].
Therefore, it would have been obvious to a person having ordinary skill in the art to modify the method taught by modified Wu to include a molar ratio of the hard segment to the soft segment as taught by Kwon, in order for the separator to have excellent thermal and mechanical stability characteristics.
Furthermore, it would have been obvious to one having ordinary skill in the art at the effective filing date of the invention to additionally determine the optimum or workable amounts of the hard and soft segments in order to achieve the desired thermal and mechanical stability characteristics [0018] given, ““[W]here 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.” In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955)”; MPEP 2144.05. See also the following case law:
“The normal desire of scientists or artisans to improve upon what is already generally known provides the motivation to determine where in a disclosed set of percentage ranges is the optimum combination of percentages.” In re Peterson, 315 F.3d at 1330, 65 USPQ2d at 1382.
Claimed elastomeric polyurethanes which fell within the broad scope of the references were held to be unpatentable thereover because, among other reasons, there was no evidence of the criticality of the claimed ranges of molecular weight or molar proportions. In re Hoeschele, 406 F.2d 1403, 160 USPQ 809 (CCPA 1969).
The discovery of an optimum value of a known result effective variable, without producing any new or unexpected results, is within the ambit of a person of ordinary skill in the art. See In re Boesch, 205 USPQ 215 (CCPA 1980) (see MPEP § 2144.05, II.).
Regarding claim 13, modified Wu teaches a method for manufacturing a separator for a lithium secondary battery as described in the rejection for instant claim 1. Wu teaches that the separator obtained by the manufacturing method comprises:
a porous base material (“porous polymer substrate”) [0026, “the electrochemical separation membrane 1 of the present invention includes a porous base material 10”, 0028, “The porous base material 10 is a polyolenfine cellulose material”]; and
a polymer gel (“porous coating layer”) on at least one surface of the porous base material [0026, “a gelatinous polymer 20 coated on at least one surface of the porous base material 10”, 0030, “wherein the polymer gel has the coherence property of solid state and the diffusion and transportation properties of liquid state, such that the electrolyte is limited in a polymer network, and the ions not only move free in the continuous micro holes”, 0040, “A porous ceramic-polymer composite membrane which can be used to an electrochemical separation membrane is obtained after drying”], wherein the polymer gel comprises ceramic particles (“inorganic particles”) [0026, “a plurality of ceramic particles 30 distributed uniformly in the gelatinous polymer 20”], and polymers such as polyurethane (“first binder polymer”) and polymethyl methacrylate (“second binder polymer”) [0031].
Regarding claim 14, Wu, as modified by Kwon and Maruoka, teaches the separator of claim 13, as described in the rejection of instant claim 13. Wu is silent regarding a lithium secondary battery comprising a positive electrode and a negative electrode.
Kwon teaches a secondary battery including a positive electrode, a negative electrode, and a separator interposed therebetween [0057]. Kwon teaches that the secondary battery may be a lithium secondary battery [0058, “The above secondary batteries include, for example, lithium secondary batteries”].
Both Kwon and Wu teach separators intended to address the limitations of polyethylene/polyolefin separators, in order to improve the safety of secondary batteries [Kwon 0002-0003, Wu 0009, “the manufacturers of the separation membrane understand the disadvantages in thermal stability of traditional separation membrane (the main material is PE) recently, and try to improve the safety”].
Therefore, it would have been obvious to a person having ordinary skill in the art prior to the effective filing date of the claimed invention to have combined the separator taught by modified Wu with the lithium secondary battery taught by Kwon to yield the predictable result of providing a lithium secondary battery including a separator with improved safety characteristics.
Claim 2 is rejected under 35 U.S.C. 103 as being unpatentable over Wu (US 2013/0327704) in view of Kwon (KR 20190056157) and Maruoka (JP 2016134247) as applied to claim 1 above, and further in view of Matsumoto et al. (US 2011/0143183, hereinafter “Matsumoto”).
Regarding claim 2, modified Wu teaches the method of claim 1, as described in the rejection of instant claim 1. Wu is silent regarding the melting point of polyurethane.
Matsumoto teaches analogous art of a separator including a multilayer porous film comprising thermoplastic resin [Abstract]. Matsumoto teaches that the thermoplastic resin has a melting point of 80°C to 180°C, which overlaps the claimed range, and that the thermoplastic resin may be a thermoplastic polyurethane [0048, “Examples of the thermoplastic resin that softens at 80 to 180°C. include thermoplastic resins having a melting point of 80 to 180°C.”, “Specific examples of the thermoplastic resins include polyolefins and thermoplastic polyurethanes”]. 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 I].
Matsumoto teaches that the thermoplastic resin having a melting point of 80°C to 180°C is able to soften within that range, therefore closing the pores of the porous film [0048, “a thermoplastic resin that softens at 80 to 180°C to close the pores”]. Matsumoto teaches that closing the pores of a porous film increases the internal resistance of the battery so as to improve the battery safety in the event of short-circuiting [0003].
Therefore, it would have been obvious to a person having ordinary skill in the art prior to the effective filing date of the claimed invention to have modified the method taught by modified Wu to have the melting point of the first binder polymer be within the range taught by Matsumoto, in order to improve battery safety.
Claim 9 is rejected under 35 U.S.C. 103 as being unpatentable over Wu (US 2013/0327704) in view of Kwon (KR 20190056157) and Maruoka (JP 2016134247) as applied to claim 1 above, and further in view of Wensley et al. (US 2004/0241550, hereinafter “Wensley”).
Regarding claim 9, modified Wu teaches the method for manufacturing the separator as described in the rejection for instant claim 1. Wu is silent regarding the relative humidity under which the drying step is carried out.
Wensley teaches analogous art of a method for manufacturing separator for a lithium battery [Abstract]. The separator has a microporous membrane (“porous substrate”) [Abstract] and a porous coating formed on the surface of the membrane [0013, “When the second solvent is driven from the coating, a porous coating of gel forming polymer resides on the surface of the membrane”]. Wensley further teaches that the method includes a drying step [0013, “The second solvent may be driven off by the application of drying energy (e.g., heat)”]. Wensley discloses that the relative humidity during the drying steps is controlled to be between 15% and 44%, which overlaps the claimed range [0020, “It has been determined that the uniformity (as measured by the McMullin Number) of the separator is improved when the percent relative humidity during the coating and drying steps is controlled to between 15-44%”]. In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists (see MPEP 2144.05 I).
Wensley teaches that the uniformity of resistance of a coated separator is very important for battery manufacturing, and that uniformity of resistance can be controlled by controlling the relative humidity [0017, “Uniformity of resistance of the coated separator is of paramount importance to the battery manufacturer. Uniformity of resistance, as measured by McMullin Number, is controlled by controlling the relative humidity (% RH) during the coating process”]. Wensley teaches that when the relative humidity is between 15% and 44% during drying, the uniformity of the resistance is improved [0020].
Therefore, it would have been obvious to a person having ordinary skill in the art to modify the method taught by modified Wu to carry out the drying step under the relative humidity range taught by Wensley, in order to improve the uniformity of resistance of the separator.
Claim 12 is rejected under 35 U.S.C. 103 as being unpatentable over Wu (US 2013/0327704) in view of Kwon (KR 20190056157) and Maruoka (JP 2016134247) as applied to claim 1 above, and further in view of Kwack et al. (US 2020/0127266, hereinafter “Kwack”) and Kim et al. (US 2009/0246614, hereinafter “Kim”).
Regarding claim 12, modified Wu teaches the method for manufacturing the separator as described in the rejection for instant claim 1. Wu is silent regarding the Lami strength adhesion of the separator to an electrode and the compression ratio of the porous polymer substrate.
Kwack teaches analogous art of a separator for a secondary battery comprising a porous substrate, a heat resistant coating layer, and an electrode adhesive layer [0020, “An aspect of the present invention provides a composite separator including a porous substrate, a heat-resistant coating layer formed on the porous substrate, and an electrode adhesive layer”]. Kwack teaches that the separator has a peel strength (“Lami strength adhesion”) of 10 to 150 gf/25 mm to a carbon sheet (taking the place of an “electrode”) [0077, “the composite separator may have a peel strength of 10 to 150 gf/25 mm … when the composite separator is stacked on a carbon sheet”, 0090, “A carbon sheet having a thickness of 200 μm (manufactured by TOYO TANSO KOREA CO., LTD., product name: PF-20HP) was used instead of an electrode”], which overlaps with the claimed range. In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists (see MPEP 2144.05 I).
Kwack teaches that when the separator and electrode, or electrode assembly, are manufactured with the peel strength of the above range, distortion and lifting of the separator is suppressed, battery capacity maximized, and cycle characteristics improved [0077, “When the electrode assembly is manufactured in the above ranges, the occurrence of distortion or lifting phenomenon may be suppressed. Therefore, also the battery capacity may be maximized, and a battery having excellent cycle characteristics may be provided”].
Therefore, it would have been obvious to a person having ordinary skill in the art to modify the method taught by modified Wu to give the separator the peel strength to an electrode in the range taught by Kwack, in order to suppress distortion and lifting of the separator, maximize battery capacity, and improve cycle characteristics.
Kim teaches analogous art of a separator for a secondary battery comprising a porous layer and a polyolefin-based resin layer (“porous polymer substrate”) [0021, “ the separator includes a porous layer comprising a ceramic material and a binder, and a polyolefin-based resin layer”]. Kim teaches that the porous layer can be formed on the polyolefin-based resin layer, which is porous, and that the polyolefin-based resin layer may have a compressibility (“compression ratio”) of 4% to 10% [0027, “the polyolefin-based resin layer has a porosity of 30% to 60%, and the polyolefin-based resin layer has a compressibility of 4% to 10%”].
Kim teaches that the compressibility of the polyolefin-based resin layer affects the lithium ion mobility in the battery [0046, “compressibility may be taken into account as another property of a separator having an effect on lithium ion mobility”]. Kim teaches that when the compressibility is too high, electrolyte can flow out of the separator and worsen its lifespan, but if it’s too low, the separator is less flexible, potentially causing the separator to break or unwind [0047].
Therefore, it would have been obvious to a person having ordinary skill in the art to modify the method taught by modified Wu to give the porous polymer substrate a compressibility in the range taught by Kim, in order to prevent worsening the separator lifespan or breakage or unwinding of the separator.
Response to Arguments
Applicant's arguments filed 3/18/2026 have been fully considered but they are not persuasive.
In response to applicant’s argument that there is no teaching, suggestion, or motivation to combine the references, the examiner recognizes that obviousness may be established by combining or modifying the teachings of the prior art to produce the claimed invention where there is some teaching, suggestion, or motivation to do so found either in the references themselves or in the knowledge generally available to one of ordinary skill in the art. See In re Fine, 837 F.2d 1071, 5 USPQ2d 1596 (Fed. Cir. 1988), In re Jones, 958 F.2d 347, 21 USPQ2d 1941 (Fed. Cir. 1992), and KSR International Co. v. Teleflex, Inc., 550 U.S. 398, 82 USPQ2d 1385 (2007). In this case, the motivation of the modification of Wu with Kwon is found in Kwon’s teaching that including a polymer with a hard and soft segment in a separator imparts a shutdown function to the separator during overheating and prevents ignition or explosion of the battery [0015], as well as Kwon’s teaching that the glass transition temperature of a polymer contributes to the shutdown function, which enhances the heat safety of the battery [0096], as described in the rejection of instant claim 1. The motivation of the modification of Wu with Maruoka is found in Maruoka’s teaching that the amount of polyurethane in a separator can affect the adhesive quality, dimensional stability at high temperature, and permeability of the separator [0044], as described in the rejection of instant claim 1. Therefore, this argument is considered unpersuasive and the rejection of claim 1 as obvious over Wu in view of Kwon and Maruoka is maintained.
In response to applicant's argument that "none of the applied references contemplate applying a slurry for forming a porous coating layer by dissolving a first binder polymer and a second binder polymer having predetermined properties in an asymmetric linear ketone solvent in order to make it possible to improve adhesion (Lami strength) to an electrode and to increase the compression resistance of the separator" [Remarks, pg. 6], the fact that the inventor has recognized another advantage which would flow naturally from following the suggestion of the prior art cannot be the basis for patentability when the differences would otherwise be obvious. See Ex parte Obiaya, 227 USPQ 58, 60 (Bd. Pat. App. & Inter. 1985). Therefore, this argument is considered unpersuasive and the rejection of claim 1 as obvious over Wu in view of Kwon and Maruoka is maintained.
Applicant alleges that "the comparative evidence in the specification establishes the unexpected results of forming a porous coating layer by dissolving a first binder polymer and a second binder polymer having predetermined properties in an asymmetric linear ketone solvent" [Remarks, pg. 6]. Applicant cites the results of Examples 1-5 and Comparative Examples 1-8, summarized in Tables 1 and 2 of the filed specification to support this allegation.
It is respectfully submitted that there are multiple deficiencies with respect to Applicant’s allegation of unexpected results.
The first overarching issue is that whether the unexpected results are the result of unexpectedly improved results or a property not taught by the prior art, the "objective evidence of nonobviousness must be commensurate in scope with the claims which the evidence is offered to support." [MPEP 716.02(d)] (Examiner emphasis). In other words, the showing of unexpected results must be reviewed to see if the results occur over the entire claimed range. In re Clemens, 622 F.2d 1029, 1036, 206 USPQ 289, 296 (CCPA 1980). See also the following case law[(MPEP 716.02(d)]:
In re Peterson, 315 F.3d 1325, 1329-31, 65 USPQ2d 1379, 1382-85 (Fed. Cir. 2003) (data showing improved alloy strength with the addition of 2% rhenium did not evidence unexpected results for the entire claimed range of about 1-3% rhenium);
In re Grasselli, 713 F.2d 731, 741, 218 USPQ 769, 777 (Fed. Cir. 1983) (Claims were directed to certain catalysts containing an alkali metal. Evidence presented to rebut an obviousness rejection compared catalysts containing sodium with the prior art. The court held this evidence insufficient to rebut the prima facie case because experiments limited to sodium were not commensurate in scope with the claims.); and
In re Lindner, 457 F.2d 506, 509, 173 USPQ 356, 359 (CCPA 1972) (Evidence of nonobviousness consisted of comparing a single composition within the broad scope of the claims with the prior art. The court did not find the evidence sufficient to rebut the prima facie case of obviousness because there was "no adequate basis for reasonably concluding that the great number and variety of compositions included in the claims would behave in the same manner as the tested composition.")
The evidenced offered to support the allegation of unexpected results is not commensurate in scope with the claim. For example, in the case law of In re Grasselli cited above, the evidence of experiments limited to sodium were considered insufficient to rebut the prima facie case of obviousness because the claims were directed to catalysts containing an alkali metal (sodium being a species of the genus alkali metal of which there are only six alkali metals). Likewise, in terms of rebutting a prima facie case of obviousness on the basis of unexpected results, the single species of AM160 does not provide sufficient evidence for the claimed genus of “thermoplastic polyurethane”. The instant specification specifically teaches that the molar ratio of the hard segment to the soft segment in the first binder polymer can have an effect on its properties as a thermoplastic elastomer and the temperature at which its association region is dissociated [0048 of published application]. The specification further discloses that the weight average molecular weight of the first binder polymer can have an effect on the first binder polymer accomplishing a desired object of the present disclosure effectively [0049 of the published application]. Therefore, it is not likely that any thermoplastic polyurethane that meets the sole requirement of having a polyol-derived repeating unit and a hard segment binding structure will achieve the same alleged unexpected results. Of note is that the claims entirely omit the use of isopropyl trioleyl titanate as a dispersing agent although every example provided as support for the allegation of unexpected results utilizes isopropyl trioleyl titanate as part of the slurry for forming a porous coating layer.
As to the range of “the first binder polymer and the second binder polymer are introduced into the solvent at a weight ratio in a range of 90:10 to 30:70”, in order to establish unexpected results over a claimed range, applicants should compare a sufficient number of tests both inside and outside the claimed range to show the criticality of the claimed range. In re Hill, 284 F.2d 955, 128 USPQ 197 (CCPA 1960). A single comparative example outside the lower limit of the range (at 10:90 - Comparative Example 8) and a single comparative example outside the upper limit of the range (at 100:0 - Comparative Example 3) is not a “sufficient number of tests” outside the claimed range to show criticality of the range. There is no data, for example, at a weight ratio of the first binder polymer to the second binder polymer of 20:80, 25:75, etc. Therefore, it is unclear whether any improvements in adhesion truly end at a weight ratio of the first binder polymer to the second binder polymer of 30:70. Similarly, there is no data for a weight ratio of the first binder polymer to the second binder polymer of, for example, 95:5, which would be helpful in determining whether any unexpected results truly end at a weight ratio of the first binder polymer to the second binder polymer of 90:10.
As such, the Examiner does not find the objective evidence offered to support the allegation of nonobviousness in terms of unexpected results commensurate in scope with the claims which the evidence is offered to support [MPEP 7160.02(d)]. Therefore, this argument is considered unpersuasive and the rejection of claim 1 as obvious over Wu in view of Kwon and Maruoka is maintained.
Conclusion
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/M.F.O./Examiner, Art Unit 1729
/ULA C RUDDOCK/Supervisory Patent Examiner, Art Unit 1729
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