DETAILED ACTION
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on March 27, 2026 has been entered.
Claims 1 and 49 are currently amended. Claims 1, 4, 5, 10, 14-16, 18, 20-27, 48 and 49 are pending review in this action.
New grounds of rejection necessitated by Applicant’s amendments are presented below.
Response to Amendment
The declaration under 37 CFR 1.132 filed on February 27, 2026 is insufficient to overcome the rejection of claims 1, 4, 5, 10, 14-16, 18, 20-27, 48 and 49 are rejected under 35 U.S.C. 103 as being unpatentable over Miller (US PG Pub 2014/0255789) in view of Miller ‘127 (US PG Pub 2009/0305127), Whear (US PG Pub 2012/0070713), Pekala (US PG Pub 2016/0028060), Whear ‘747 (US PG Pub 2012/0070747), Schmidt (US Patent No. 4,440,838) and Yaacoub (US Patent No. 5,246,798), with evidence from Elé Corporation as set forth in the last Office action for the reasons articulated below.
Applicant’s arguments are addressed below in the order presented in the declaration and numbered as presented in the declaration.
8. Applicant argues that the inventors of the present application were looking for an anti-foaming agent and would choose an HLB value from 1 to 3 and not 7 to 9, “which is a wetting and spreading agent”.
It is not immediately clear why applicant is arguing against an HLB value of 7 to 9. The prior art reference (Schmidt) used in the prior and current office actions to address the HLB value limitation teaches surfactants with an HLB value of less than 5 (col. 4, lines 56-68).
9. Applicant argues that 40-70% silica filled membranes are wettable with sulfuric acid and do not require an additional surfactant to impart wettability.
It is firstly noted that the Whear ‘747 reference teaches precisely this type of membrane and explicitly teaches including a wetting agent (paragraph [0042]). Further, the Pekala reference discusses separators containing 55-70 wt% silica filler and teaches that even in those separators there are “polymer rich” pores that are not accessible to the electrolyte (paragraph [0026]). Thus, the prior art appreciates that even separators with high silica concentrations can benefit from a wetting agent.
10. Applicant argues that the instantly disclosed separators are 40-70% silica filled membranes and do not need a surfactant with an HLB value of 7 to 9.
As in argument 8 above, it is not immediately clear why applicant is arguing against an HLB value of 7 to 9. The prior art reference (Schmidt) used in the prior office action to address the HLB value limitation teaches surfactants with an HLB value of less than 5 (col. 4, lines 56-68).
11. Applicant argues against the Elé reference. Specifically, applicant argues that Elé is not directed to acid electrolyte, is not accurate, is not enabling, does not list surfactants with an HLB value less than 3.
Elé is not used to select surfactants. The compounds used as surfactants are already taught by the Whear ‘747 (paragraphs [0119-0166]). The HLB value (less than 5) is taught by Schmidt (col. 4, lines 56-68).
12. Applicant restates claims 1 and 49 and argues that surfactant properties are pH dependent.
No argument related to pH is presented in the current or prior office action.
13. Applicant argues without evidence that Schmidt prefers wetting agents that are water soluble and further argues that Schmidt teaches away from a non-ionic surfactant with an HLB of less than 5 and that is not soluble in water.
Schmidt is directed to a polyolefin based separator for a lead-acid battery and a non-ionic surfactant with an HLB value of less than 5. Given its low hydrophilicity (as indicated by an HLB value in a range that goes to 0), such a surfactant is expected to not be soluble in water.
14. Applicant argues that one of ordinary skill would not look to Schmidt to modify a silica filled polymer membrane.
All of the references (including Miller, Whear ‘747 and Schmidt) teach a polyethylene-based separator for a lead-acid battery. Both Whear ‘747 and Schmidt teach using a non-ionic surfactant and specifically one that is based on alkylene oxides. Schmidt provides a clear motivation for the HLB value of the surfactant (less than 5).
15. Applicant argues that Schmidt is directed to wetting agents that tend to be soluble in water.
Schmidt does not describe the wetting agents as being soluble in water. It is unclear why applicant makes such a claim. Applicant is welcome to provide examples of non-ionic surfactants taught by Schmidt and having an HLB value of say 1 that are water-soluble.
Compact Prosecution
In the interest of compact prosecution, in addition to the grounds of rejection presented in the prior office action, a new ground of rejection is also provided below.
Claim Rejections - 35 USC § 103
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, 4, 5, 10, 14-16, 18, 20-27, 48 and 49 are rejected under 35 U.S.C. 103 as being unpatentable over U.S. Pre-Grant Publication No. 2014/0255789, hereinafter Miller in view of U.S. Pre-Grant Publication No. 2009/0305127, hereinafter Miller ‘127, U.S. Pre-Grant Publication No. 2012/0070713, hereinafter Whear, U.S. Pre-Grant Publication No. 2016/0028060, hereinafter Pekala, U.S. Pre-Grant Publication No. 2012/0070747, hereinafter Whear‘747, U.S. Patent No. 3,933,525, hereinafter Palmer, U.S. Patent No. 3,967,978, hereinafter Honda and U.S. Patent No. 5,246,798, hereinafter Yaacoub.
Regarding claim 1, Miller teaches a battery separator for a lead-acid battery having an acid electrolyte. The battery separator comprises a porous polyolefin membrane. The porous membrane comprises a polymer material such as polyethylene (“base material”), a silica (“particle-like”) filler and rubber (paragraphs [0014, 0015]).
The rubber is latex, tire crumb (“crosslinked rubber”), uncrosslinked rubber, uncured rubber, natural rubber or synthetic rubber (paragraph [0015]).
The rubber is impregnated into the membrane and is present at a concentration of 1-12 % by weight (paragraph [0017]).
The membrane is prepared in the conventional way using processing oil, which is extracted after extrusion and calendering (paragraph [0018]).
Miller fails to: 1) specify the relative concentrations of the polymer material (“base material”), the silica filler and their ratio; 2) specify the amount of residual processing oil left in the membrane; 3) specify a backweb thickness and 4) teach a surfactant.
Regarding 1), the Miller ‘127 reference, which shares inventors with and is commonly owned with the Miller reference, teaches an analogous silica-filled polyethylene separator for a lead-acid battery. Miller ‘127 teaches that the silica filler is present at a concentration in the range 5-95 percent by weight and a ratio of filler to polyethylene (“base material”) is in the range 0.1:1 to 15:1 (paragraph [0030]). The corresponding polyethylene (“base material”) concentration range can be calculated from the filler concentration range and the ratio range and overlaps the instantly claimed range. In a specific example, Miller ‘127 teaches a ratio of 2.6:1 (Example A).
Therefore it would have been obvious to the ordinarily skilled artist before the effective filing date of the claimed invention to adopt the concentration ranges and ratio of Miller ‘127 for the purpose of forming the membrane without undue experimentation and with a reasonable expectation of success.
Regarding 2), Pekala teaches an analogous silica-filled polyethylene separator for a lead-acid battery. Pekala’s separator is formed using an analogous process using processing oil which is extracted after extrusion and calendering (paragraphs [0019, 0020]). In various examples, Pekala reports silica filler to polyethylene ratios lower than 3:1 (paragraphs [0017, 0018]). Pekala teaches that a processed separator typically contains 12-21 wt% processing oil (paragraph [0023]).
Therefore it would have been obvious to the ordinarily skilled artist before the effective filing date of the claimed invention to form the separator such that it contains 12-21 wt% processing oil without undue experimentation and with a reasonable expectation of success.
Regarding 3), it is well-known in the art that backweb thicknesses are a design option motivated by the intended properties of the separator. The Whear reference, which is commonly owned with and shares inventors with the Miller reference, teaches analogous silica-filled polyethylene separators for lead-acid batteries with substrate (backweb) thickness in the range 65 µm to 750 µm (paragraph [0235]).
Therefore it would have been obvious to the ordinarily skilled artist before the effective filing date of the claimed invention to form Miller’s separator with a backweb thickness in the range 65 µm to 750 µm without undue experimentation and with a reasonable expectation of success.
Regarding 4), the use of surfactants as wetting agents in forming silica-filled polyethylene separators for lead-acid batteries is well-known in the art – see, e.g. Miller ‘127 (paragraph [0029]) and Pekala (paragraphs [0026-0028]). The Whear‘747 reference, which is commonly owned with the Miller reference teaches using various surfactants such as non-ionic surfactants and a sulfosuccinate (paragraphs [0119, 0124, 0141-0166]). Whear‘747 teaches block copolymers of polyethylene glycol and polypropylene glycol as non-ionic surfactants (paragraph [0166]). Polyethylene glycol is prepared by polymerizing ethylene oxide and polypropylene glycol is prepared by polymerizing propylene oxide. Therefore, the compounds taught by Whear‘747 are among the class of block copolymers of ethylene oxide and propylene oxide.
Palmer teaches a polyolefin separator for a lead-acid battery. Palmer teaches applying a surfactant with an HLB (“hydrophilic-lipophilic balance”) value of less than 5, because such surfactants provide hydrophilicity to the polyolefin and thus allow robust wetting of the separator, while also not being easily washed away (col. 5, lines 35-42). Palmer further teaches that such surfactants result in low foaming in the battery (col. 6, lines 2-5; col. 1, lines 58-59). Palmer lists Pluronic L-121 as an example surfactant (col. 5, lines 55-56). Pluronic L-121 is a block copolymer of ethylene oxide and propylene oxide.
Honda teaches a porous separator for a lead-acid battery, which includes a polyolefin base and silica filler (col. 2, lines 44-46, 56-57, col. 3, lines 12-16). Honda teaches that the separator includes a non-ionic, water-insoluble surfactant that is a copolymer of polyethylene glycol and polypropylene glycol (col. 4, lines 40-45). The separator further includes an anionic surfactant, which is a sulfosuccinate (col. 4, lines 46-55). Honda teaches that the surfactants enable the permeation of the electrolytic solution into the pores of the separator (col. 4, lines 56-64).
Treating the surface of a separator membrane with surfactant at concentrations greater than 0.5 g/m2 is known in the art – see, e.g. Yaacoub (col. 5, lines 29, 30, 60-63). In a specific example, Yaacoub teaches a concentration of 2.5 g/m2 (col. 7, lines 58-62).
Therefore it would have been obvious to the ordinarily skilled artist before the effective filing date of the claimed invention to select a sulfosuccinate and a water-insoluble, non-ionic surfactant, which is a block copolymer of ethylene oxide and propylene oxide having a HLB value of less than 5 and to apply the surfactant at a concentration of 2.5 g/m2 for the purpose of ensuring a robust wetting effect and low foaming.
The ranges for the concentrations of the polymer base material, the filler and the residual processing oil, the backweb thickness and the HLB value in Miller as modified by Miller ‘127, Pekala, Whear and Schmidt overlap the instant application's optimum ranges of 5-15 wt%, 40-70 wt%, 20-30 wt%, 275 µm to 500 µm and less than 3, respectively. It has been held that in the case where claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. See MPEP 2144.05.
Regarding claims 4 and 5, Miller teaches that the rubber is methyl rubber, polybutadiene, chloroprene rubbers, butyl rubber, bromobutyl rubber, polyurethane rubber, epichlorohydrin rubber, polysulphide rubber, chlorosulphonyl polyethylene, polynorborene rubber, acrylate rubber, fluorine rubber, silicone rubber or copolymer rubbers. The copolymer rubbers may be styrene/butadiene, acrylonitrile/butadiene, ethylene/propylene rubbers (EPM and EPDM) and ethylene/vinyl acetate rubbers (paragraph [0015]).
Regarding claim 10, Miller teaches rubber present at a concentration of 1.2-6 % by weight (paragraph [0017]).
Regarding claims 14-16, Miller as modified by Yaacoub teaches that the surfactant should be applied at a concentration greater than 0.5 g/m2 (Yaacoub’s col. 5, lines 60-63). In a specific example, Yaacoub teaches a concentration of 2.5 g/m2 (Yaacoub’s col. 7, lines 58-62).
Regarding claim 18, Miller teaches that the filler is silica (paragraph [0014]).
Regarding claim 20, Miller teaches processing oil (paragraphs [0014, 0018]).
Regarding claim 21, Miller teaches that the separator includes a glass mat (paragraph [0012]).
Miller does not specify that the glass mat is laminated to the porous membrane.
The commonly owned Whear reference teaches that the glass mat is laminated to the porous membrane to form the separator (see, e.g. figure 32).
Therefore it would have been obvious to the ordinarily skilled artist before the effective filing date of the claimed invention to laminate the glass mat to the porous membrane for the purpose of forming the separator.
Regarding claim 22, Miller teaches a glass mat.
Miller does not specify glass fibers.
It is well-known in the art that glass mats used in separators of the kind taught by Miller are formed of glass fibers – see, e.g. the commonly owned Whear reference (paragraph [0307]).
Therefore it would have been obvious to the ordinarily skilled artist before the effective filing date of the claimed invention to form Miller’s glass mat of glass fibers for the purpose of achieving a desired porosity and mechanical properties of the glass mat.
Regarding claims 23 and 24, Miller as modified by Whear teaches that the substrate (backweb) thickness is in the range 65 µm to 750 µm (paragraph [0235]).
Miller as modified by Whear’s optimum range overlaps the instant application's optimum ranges of 300 µm to 500 µm and 350 µm to 500 µm. It has been held that in the case where claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. See MPEP 2144.05.
Regarding claim 25, Miller teaches that the separator includes positive ribs, cross ribs and channels (paragraph [0014, 0018]).
Regarding claim 26, Miller teaches that the rubber is impregnated in the microporous membrane and the ribs are formed by calendering the membrane (paragraph [0018]). Therefore, the ribs include the rubber.
Regarding claim 27, Miller teaches that the separator is in the shape of a cut piece, envelope or pocket (paragraph [0012]).
Regarding claim 48, Miller teaches that the polymer material (“base material”) comprises polypropylene, polyethylene, ultra-high molecular weight polyethylene, polyvinyl chloride, phenolic resin and the like (paragraph [0014]).
Regarding claim 49, Miller teaches a battery separator for a lead-acid battery. The battery separator comprises a porous membrane. The porous membrane comprises a polymer material such as polyethylene (“base material”), a silica (“particle-like”) filler and rubber (paragraphs [0014, 0015]).
The rubber is impregnated into the membrane and is present at a concentration of 1-12 % by weight (paragraph [0017]).
The membrane is prepared in the conventional way using processing oil, which is extracted after extrusion and calendering (paragraph [0018]).
Miller fails to: 1) specify the relative concentrations of the polymer material (“base material”) and the silica filler; 2) specify the amount of residual processing oil left in the membrane; 3) specify a backweb thickness; and 4) teach a surfactant.
Regarding 1), the Miller ‘127 reference, which shares inventors with and is commonly owned with the Miller reference, teaches an analogous silica-filled polyethylene separator for a lead-acid battery. Miller ‘127 teaches that the silica filler is present at a concentration in the range 5-95 percent by weight and a ratio of filler to polyethylene (“base material”) is in the range 0.1:1 to 15:1 (paragraph [0030]). The corresponding polyethylene (“base material”) concentration range can be calculated from the filler concentration range and the ratio range and overlaps the instantly claimed range.
Therefore it would have been obvious to the ordinarily skilled artist before the effective filing date of the claimed invention to adopt the concentration ranges of Miller ‘127 for the purpose of forming the membrane without undue experimentation and with a reasonable expectation of success.
Regarding 2), Pekala teaches an analogous silica-filled polyethylene separator for a lead-acid battery. Pekala’s separator is formed using an analogous process using processing oil which is extracted after extrusion and calendering (paragraphs [0019, 0020]). In various examples, Pekala reports silica filler to polyethylene ratios lower than 3:1 (paragraphs [0017, 0018]). Pekala teaches that a processed separator typically contains 12-21 wt% processing oil (paragraph [0023]).
Therefore it would have been obvious to the ordinarily skilled artist before the effective filing date of the claimed invention to form the separator such that it contains 12-21 wt% processing oil without undue experimentation and with a reasonable expectation of success.
Regarding 3), it is well-known in the art that backweb thicknesses are a design option motivated by the intended properties of the separator. The Whear reference, which is commonly owned with and shares inventors with the Miller reference, teaches analogous silica-filled polyethylene separators for lead-acid batteries with substrate (backweb) thickness in the range 65 µm to 750 µm (paragraph [0235]).
Therefore it would have been obvious to the ordinarily skilled artist before the effective filing date of the claimed invention to form Miller’s separator with a backweb thickness in the range 65 µm to 750 µm without undue experimentation and with a reasonable expectation of success.
Regarding 4), the use of surfactants as wetting agents in forming silica-filled polyethylene separators for lead-acid batteries is well-known in the art – see, e.g. Miller ‘127 (paragraph [0029]) and Pekala (paragraphs [0026-0028]). The Whear‘747 reference, which is commonly owned with the Miller reference teaches using various surfactants such as non-ionic surfactants and a sulfosuccinate (paragraphs [0119, 0124, 0141-0166]). Whear‘747 teaches block copolymers of polyethylene glycol and polypropylene glycol as non-ionic surfactants (paragraph [0166]). Polyethylene glycol is prepared by polymerizing ethylene oxide and polypropylene glycol is prepared by polymerizing propylene oxide. Therefore, the compounds taught by Whear‘747 are among the class of block copolymers of ethylene oxide and propylene oxide.
Palmer teaches a polyolefin separator for a lead-acid battery. Palmer teaches applying a surfactant with an HLB (“hydrophilic-lipophilic balance”) value of less than 5, because such surfactants provide hydrophilicity to the polyolefin and thus allow robust wetting of the separator, while also not being easily washed away (col. 5, lines 35-42). Palmer further teaches that such surfactants result in low foaming in the battery (col. 6, lines 2-5; col. 1, lines 58-59). Palmer lists Pluronic L-121 as an example surfactant (col. 5, lines 55-56). Pluronic L-121 is a block copolymer of ethylene oxide and propylene oxide.
Honda teaches a porous separator for a lead-acid battery, which includes a polyolefin base and silica filler (col. 2, lines 44-46, 56-57, col. 3, lines 12-16). Honda teaches that the separator includes a non-ionic, water-insoluble surfactant that is a copolymer of polyethylene glycol and polypropylene glycol (col. 4, lines 40-45). The separator further includes an anionic surfactant, which is a sulfosuccinate (col. 4, lines 46-55). Honda teaches that the surfactants enable the permeation of the electrolytic solution into the pores of the separator (col. 4, lines 56-64).
Treating the surface of a separator membrane with surfactant at concentrations greater than 0.5 g/m2 is known in the art – see, e.g. Yaacoub (col. 5, lines 29, 30, 60-63). In a specific example, Yaacoub teaches a concentration of 2.5 g/m2 (col. 7, lines 58-62).
Therefore it would have been obvious to the ordinarily skilled artist before the effective filing date of the claimed invention to select a sulfosuccinate and a water-insoluble, non-ionic surfactant, which is a block copolymer of ethylene oxide and propylene oxide having a HLB value of less than 5 and to apply the surfactant at a concentration of 2.5 g/m2 for the purpose of ensuring a robust wetting effect and low foaming.
The ranges for the concentrations of the polymer base material, the filler and the residual processing oil, the backweb thickness and HLB value in Miller as modified by Miller ‘127, Pekala, Whear and Schmidt overlap the instant application's optimum ranges of 5-15 wt%, 40-70 wt%, 20-30 wt%, and 275 µm to 500 µm, respectively. It has been held that in the case where claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. See MPEP 2144.05.
Claims 1, 4, 5, 10, 14-16, 18, 20-27, 48 and 49 are rejected under 35 U.S.C. 103 as being unpatentable over U.S. Pre-Grant Publication No. 2014/0255789, hereinafter Miller in view of U.S. Pre-Grant Publication No. 2009/0305127, hereinafter Miller ‘127, U.S. Pre-Grant Publication No. 2012/0070713, hereinafter Whear, U.S. Pre-Grant Publication No. 2016/0028060, hereinafter Pekala, U.S. Pre-Grant Publication No. 2012/0070747, hereinafter Whear‘747, U.S. Patent No. 4,440,838, hereinafter Schmidt and U.S. Patent No. 5,246,798, hereinafter Yaacoub, with evidence from Elé Corporation and U.S. U.S. Patent No. 3,933,525, hereinafter Palmer.
Regarding claim 1, Miller teaches a battery separator for a lead-acid battery. The battery separator comprises a porous membrane. The porous membrane comprises a polymer material such as polyethylene (“base material”), a silica (“particle-like”) filler and rubber (paragraphs [0014, 0015]).
The rubber is latex, tire crumb (“crosslinked rubber”), uncrosslinked rubber, uncured rubber, natural rubber or synthetic rubber (paragraph [0015]).
The rubber is impregnated into the membrane and is present at a concentration of 1-12 % by weight (paragraph [0017]).
The membrane is prepared in the conventional way using processing oil, which is extracted after extrusion and calendering (paragraph [0018]).
Miller fails to: 1) specify the relative concentrations of the polymer material (“base material”), the silica filler and their ratio; 2) specify the amount of residual processing oil left in the membrane; 3) specify a backweb thickness and 4) teach a surfactant.
Regarding 1), the Miller ‘127 reference, which shares inventors with and is commonly owned with the Miller reference, teaches an analogous silica-filled polyethylene separator for a lead-acid battery. Miller ‘127 teaches that the silica filler is present at a concentration in the range 5-95 percent by weight and a ratio of filler to polyethylene (“base material”) is in the range 0.1:1 to 15:1 (paragraph [0030]). The corresponding polyethylene (“base material”) concentration range can be calculated from the filler concentration range and the ratio range and overlaps the instantly claimed range. In a specific example, Miller ‘127 teaches a ratio of 2.6:1 (Example A).
Therefore it would have been obvious to the ordinarily skilled artist before the effective filing date of the claimed invention to adopt the concentration ranges and ratio of Miller ‘127 for the purpose of forming the membrane without undue experimentation and with a reasonable expectation of success.
Regarding 2), Pekala teaches an analogous silica-filled polyethylene separator for a lead-acid battery. Pekala’s separator is formed using an analogous process using processing oil which is extracted after extrusion and calendering (paragraphs [0019, 0020]). In various examples, Pekala reports silica filler to polyethylene ratios lower than 3:1 (paragraphs [0017, 0018]). Pekala teaches that a processed separator typically contains 12-21 wt% processing oil (paragraph [0023]).
Therefore it would have been obvious to the ordinarily skilled artist before the effective filing date of the claimed invention to form the separator such that it contains 12-21 wt% processing oil without undue experimentation and with a reasonable expectation of success.
Regarding 3), it is well-known in the art that backweb thicknesses are a design option motivated by the intended properties of the separator. The Whear reference, which is commonly owned with and shares inventors with the Miller reference, teaches analogous silica-filled polyethylene separators for lead-acid batteries with substrate (backweb) thickness in the range 65 µm to 750 µm (paragraph [0235]).
Therefore it would have been obvious to the ordinarily skilled artist before the effective filing date of the claimed invention to form Miller’s separator with a backweb thickness in the range 65 µm to 750 µm without undue experimentation and with a reasonable expectation of success.
Regarding 4), the use of surfactants as wetting agents in forming silica-filled polyethylene separators for lead-acid batteries is well-known in the art – see, e.g. Miller ‘127 (paragraph [0029]) and Pekala (paragraphs [0026-0028]). The Whear‘747 reference, which is commonly owned with the Miller reference teaches using various surfactants such as non-ionic surfactants and a sulfosuccinate (paragraphs [0119, 0124, 0141-0166]). Whear‘747 teaches block copolymers of polyethylene glycol and polypropylene glycol as non-ionic surfactants (paragraph [0166]). Polyethylene glycol is prepared by polymerizing ethylene oxide and polypropylene glycol is prepared by polymerizing propylene oxide. Therefore, the compounds taught by Whear‘747 are among the class of block copolymers of ethylene oxide and propylene oxide.
Schmidt teaches a polyolefin separator for a lead-acid battery (abstract). Schmidt teaches applying a surfactant with an HLB (“hydrophilic-lipophilic balance”) value of less than 5, because such surfactants provide some hydrophilicity to the polyolefin and thus allow robust wetting of the separator, while also not being easily washed away by the electrolyte. Schmidt explicitly describes a non-ionic surfactant which is a block copolymer of alkylene oxides (col. 4, lines 56-68).
Treating the surface of a separator membrane with surfactant at concentrations greater than 0.5 g/m2 is known in the art – see, e.g. Yaacoub (col. 5, lines 29, 30, 60-63). In a specific example, Yaacoub teaches a concentration of 2.5 g/m2 (col. 7, lines 58-62). Yaacoub further teaches a number of suitable non-ionic surfactants, which include various amine ethoxylates (col. 4, lines 67-68; col. 5, lines 1-2).
Therefore it would have been obvious to the ordinarily skilled artist before the effective filing date of the claimed invention to select a sulfosuccinate and a non-ionic surfactant, which is a block copolymer of ethylene oxide and propylene oxide having a HLB value of less than 5 and to apply the surfactant at a concentration of 2.5 g/m2 for the purpose of ensuring a robust wetting effect.
In the art, a surfactant with an HLB value of less than 10 is considered not soluble in water – see Elé Corporation. As such, the block copolymer of ethylene oxide and propylene oxide having a HLB value of less than 5 is expected to be not soluble in water.
See also Palmer, who describes nonionic surfactant with HLB value of less than 5 as having “a necessary water insolubility” (col. 5, lines 22-42).
The ranges for the concentrations of the polymer base material, the filler and the residual processing oil, the backweb thickness and the HLB value in Miller as modified by Miller ‘127, Pekala, Whear and Schmidt overlap the instant application's optimum ranges of 5-15 wt%, 40-70 wt%, 20-30 wt%, 275 µm to 500 µm and less than 3, respectively. It has been held that in the case where claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. See MPEP 2144.05.
Regarding claims 4 and 5, Miller teaches that the rubber is methyl rubber, polybutadiene, chloroprene rubbers, butyl rubber, bromobutyl rubber, polyurethane rubber, epichlorohydrin rubber, polysulphide rubber, chlorosulphonyl polyethylene, polynorborene rubber, acrylate rubber, fluorine rubber, silicone rubber or copolymer rubbers. The copolymer rubbers may be styrene/butadiene, acrylonitrile/butadiene, ethylene/propylene rubbers (EPM and EPDM) and ethylene/vinyl acetate rubbers (paragraph [0015]).
Regarding claim 10, Miller teaches rubber present at a concentration of 1.2-6 % by weight (paragraph [0017]).
Regarding claims 14-16, Miller as modified by Yaacoub teaches that the surfactant should be applied at a concentration greater than 0.5 g/m2 (Yaacoub’s col. 5, lines 60-63). In a specific example, Yaacoub teaches a concentration of 2.5 g/m2 (Yaacoub’s col. 7, lines 58-62).
Regarding claim 18, Miller teaches that the filler is silica (paragraph [0014]).
Regarding claim 20, Miller teaches processing oil (paragraphs [0014, 0018]).
Regarding claim 21, Miller teaches that the separator includes a glass mat (paragraph [0012]).
Miller does not specify that the glass mat is laminated to the porous membrane.
The commonly owned Whear reference teaches that the glass mat is laminated to the porous membrane to form the separator (see, e.g. figure 32).
Therefore it would have been obvious to the ordinarily skilled artist before the effective filing date of the claimed invention to laminate the glass mat to the porous membrane for the purpose of forming the separator.
Regarding claim 22, Miller teaches a glass mat.
Miller does not specify glass fibers.
It is well-known in the art that glass mats used in separators of the kind taught by Miller are formed of glass fibers – see, e.g. the commonly owned Whear reference (paragraph [0307]).
Therefore it would have been obvious to the ordinarily skilled artist before the effective filing date of the claimed invention to form Miller’s glass mat of glass fibers for the purpose of achieving a desired porosity and mechanical properties of the glass mat.
Regarding claims 23 and 24, Miller as modified by Whear teaches that the substrate (backweb) thickness is in the range 65 µm to 750 µm (paragraph [0235]).
Miller as modified by Whear’s optimum range overlaps the instant application's optimum ranges of 300 µm to 500 µm and 350 µm to 500 µm. It has been held that in the case where claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. See MPEP 2144.05.
Regarding claim 25, Miller teaches that the separator includes positive ribs, cross ribs and channels (paragraph [0014, 0018]).
Regarding claim 26, Miller teaches that the rubber is impregnated in the microporous membrane and the ribs are formed by calendering the membrane (paragraph [0018]). Therefore, the ribs include the rubber.
Regarding claim 27, Miller teaches that the separator is in the shape of a cut piece, envelope or pocket (paragraph [0012]).
Regarding claim 48, Miller teaches that the polymer material (“base material”) comprises polypropylene, polyethylene, ultra-high molecular weight polyethylene, polyvinyl chloride, phenolic resin and the like (paragraph [0014]).
Regarding claim 49, Miller teaches a battery separator for a lead-acid battery. The battery separator comprises a porous membrane. The porous membrane comprises a polymer material such as polyethylene (“base material”), a silica (“particle-like”) filler and rubber (paragraphs [0014, 0015]).
The rubber is impregnated into the membrane and is present at a concentration of 1-12 % by weight (paragraph [0017]).
The membrane is prepared in the conventional way using processing oil, which is extracted after extrusion and calendering (paragraph [0018]).
Miller fails to: 1) specify the relative concentrations of the polymer material (“base material”) and the silica filler; 2) specify the amount of residual processing oil left in the membrane; 3) specify a backweb thickness; and 4) teach a surfactant.
Regarding 1), the Miller ‘127 reference, which shares inventors with and is commonly owned with the Miller reference, teaches an analogous silica-filled polyethylene separator for a lead-acid battery. Miller ‘127 teaches that the silica filler is present at a concentration in the range 5-95 percent by weight and a ratio of filler to polyethylene (“base material”) is in the range 0.1:1 to 15:1 (paragraph [0030]). The corresponding polyethylene (“base material”) concentration range can be calculated from the filler concentration range and the ratio range and overlaps the instantly claimed range.
Therefore it would have been obvious to the ordinarily skilled artist before the effective filing date of the claimed invention to adopt the concentration ranges of Miller ‘127 for the purpose of forming the membrane without undue experimentation and with a reasonable expectation of success.
Regarding 2), Pekala teaches an analogous silica-filled polyethylene separator for a lead-acid battery. Pekala’s separator is formed using an analogous process using processing oil which is extracted after extrusion and calendering (paragraphs [0019, 0020]). In various examples, Pekala reports silica filler to polyethylene ratios lower than 3:1 (paragraphs [0017, 0018]). Pekala teaches that a processed separator typically contains 12-21 wt% processing oil (paragraph [0023]).
Therefore it would have been obvious to the ordinarily skilled artist before the effective filing date of the claimed invention to form the separator such that it contains 12-21 wt% processing oil without undue experimentation and with a reasonable expectation of success.
Regarding 3), it is well-known in the art that backweb thicknesses are a design option motivated by the intended properties of the separator. The Whear reference, which is commonly owned with and shares inventors with the Miller reference, teaches analogous silica-filled polyethylene separators for lead-acid batteries with substrate (backweb) thickness in the range 65 µm to 750 µm (paragraph [0235]).
Therefore it would have been obvious to the ordinarily skilled artist before the effective filing date of the claimed invention to form Miller’s separator with a backweb thickness in the range 65 µm to 750 µm without undue experimentation and with a reasonable expectation of success.
Regarding 4), the use of surfactants as wetting agents in forming silica-filled polyethylene separators for lead-acid batteries is well-known in the art – see, e.g. Miller ‘127 (paragraph [0029]) and Pekala (paragraphs [0026-0028]). The Whear‘747 reference, which is commonly owned with the Miller reference teaches using various surfactants such as non-ionic surfactants and a sulfosuccinate (paragraphs [0119, 0124, 0141-0166]). Whear‘747 teaches block copolymers of polyethylene glycol and polypropylene glycol as non-ionic surfactants (paragraph [0166]). Polyethylene glycol is prepared by polymerizing ethylene oxide and polypropylene glycol is prepared by polymerizing propylene oxide. Therefore, the compounds taught by Whear‘747 are among the class of block copolymers of ethylene oxide and propylene oxide.
Schmidt teaches a polyolefin separator for a lead-acid battery (abstract). Schmidt teaches applying a surfactant with an HLB (“hydrophilic-lipophilic balance”) value of less than 5, because such surfactants provide some hydrophilicity to the polyolefin and thus allow robust wetting of the separator, while also not being easily washed away by the electrolyte. Schmidt explicitly describes a non-ionic surfactant which is a block copolymer of alkylene oxides (col. 4, lines 56-68).
Treating the surface of a separator membrane with surfactant at concentrations greater than 0.5 g/m2 is known in the art – see, e.g. Yaacoub (col. 5, lines 29, 30, 60-63). In a specific example, Yaacoub teaches a concentration of 2.5 g/m2 (col. 7, lines 58-62). Yaacoub further teaches a number of suitable non-ionic surfactants, which include various amine ethoxylates (col. 4, lines 67-68; col. 5, lines 1-2).
Therefore it would have been obvious to the ordinarily skilled artist before the effective filing date of the claimed invention to select a sulfosuccinate and a non-ionic surfactant, which is a block copolymer of ethylene oxide and propylene oxide having a HLB value of less than 5 and to apply the surfactant at a concentration of 2.5 g/m2 for the purpose of ensuring a robust wetting effect.
In the art, a surfactant with an HLB value of less than 10 is considered not soluble in water – see Elé Corporation. As such, the block copolymer of ethylene oxide and propylene oxide having a HLB value of less than 5 is expected to be not soluble in water.
See also Palmer, who describes nonionic surfactant with HLB value of less than 5 as having “a necessary water insolubility” (col. 5, lines 22-42).
The ranges for the concentrations of the polymer base material, the filler and the residual processing oil, the backweb thickness and HLB value in Miller as modified by Miller ‘127, Pekala, Whear and Schmidt overlap the instant application's optimum ranges of 5-15 wt%, 40-70 wt%, 20-30 wt%, and 275 µm to 500 µm, respectively. It has been held that in the case where claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. See MPEP 2144.05.
Response to Arguments
Applicant's arguments filed on February 27, 2026 have been fully considered but they are not persuasive.
See section Response to Amendment Above.
Conclusion
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/LILIA V. NEDIALKOVA/
Examiner
Art Unit 1724
/MIRIAM STAGG/Supervisory Patent Examiner, Art Unit 1724
Prosecution Insights