Cover film-equipped gas adsorption sheet for secondary batteries

Abstract

Provided is a gas adsorption sheet that can preferentially adsorb sulfide-based gases.　According to an embodiment of the present invention, a cover film-equipped gas adsorption sheet for secondary batteries comprises: a gas adsorption sheet for secondary batteries, which contains a heat-resistant base material and a gas adsorption layer disposed on at least one side of the heat-resistant base material; and a cover film disposed on the side of the gas adsorption layer opposite from the heat-resistant base material. This gas adsorption layer contains a binder resin and gas-adsorbing particles that are constituted of a pore-bearing inorganic porous material and that can adsorb gas.

Description

Gas absorption sheet for secondary batteries with cover film

[0001] The present invention relates to a gas adsorbent sheet with a cover film for a secondary battery.

[0002] In recent years, all-solid-state batteries have been studied as secondary batteries with high energy density. All-solid-state batteries have advantages such as excellent safety because they do not use flammable organic solvents, resistance to electrolyte degradation due to rapid charging, and stable operation in high-temperature environments. In these all-solid-state batteries, sulfide-based solid electrolytes are commonly used from the viewpoint of output current.

[0003] Japanese Patent Application Laid-Open No. 2020-187855

[0004] However, in all-solid-state batteries constructed using a sulfide-based solid electrolyte, when the sulfide-based solid electrolyte comes into contact with water, sulfide-based gases such as hydrogen sulfide are generated, posing a safety issue due to gas leakage. The present invention has been made to solve such problems, and its object is to provide a gas adsorption sheet that can preferably adsorb sulfide-based gases.

[0005] [1] A gas adsorption sheet for a secondary battery with a cover film according to an embodiment of the present invention comprises a gas adsorption sheet for a secondary battery including a heat-resistant substrate and a gas adsorption layer disposed on at least one side of the heat-resistant substrate; and a cover film disposed on the gas adsorption layer opposite the heat-resistant substrate. The gas adsorption layer is composed of a binder resin and an inorganic porous material having pores and contains gas adsorption particles capable of adsorbing gas. [2] The gas adsorption sheet for a secondary battery with a cover film described in [1] above may further comprise an intermediate layer disposed between the heat-resistant substrate and the gas adsorption layer. [3] In the gas adsorption sheet for a secondary battery with a cover film described in [1] or [2] above, the gas adsorption particles may be a composite of a silicate and at least one metal salt selected from copper, zinc, manganese, cobalt, and nickel, and the pore volume of the gas adsorption particles may preferably be 0.3 ml / g to 0.5 ml / g. [4] In the gas adsorption sheet for a secondary battery with a cover film according to any one of [1] to [3] above, the gas adsorption particles may have a surface treated with silicone. [5] In the gas adsorption sheet for a secondary battery with a cover film according to [4] above, the silicone may have an ethoxysilane group or a methoxysilane group. [6] In the gas adsorption sheet for a secondary battery with a cover film according to [4] above, the silicone may be a silane coupling agent containing an epoxy group or an amino group. [7] In the gas adsorption sheet for a secondary battery with a cover film according to [4] above, the silicone may be an alkoxysilane or an organosilazane compound. [8] In the gas adsorption sheet for a secondary battery with a cover film according to any one of [1] to [7] above, the binder resin may be an acrylic resin. [9] In the gas adsorption sheet for a secondary battery with a cover film according to the above item [8], the binder resin may contain a structural unit derived from a (meth)acrylic acid alkyl ester, and the (meth)acrylic acid alkyl ester may have a linear or branched alkyl group having 4 to 12 carbon atoms.

[10] In the gas adsorption sheet for a secondary battery with a cover film described in any one of [1] to [9] above, the binder resin may be butyl rubber, isoprene rubber, polyisobutylene rubber, ethylene propylene rubber, or a silicone-based resin.

[11] In the gas adsorption sheet for a secondary battery with a cover film described in any one of [1] to

[10] above, the content of the gas adsorption particles may be 10 to 90 parts by weight per 100 parts by weight of the gas adsorption sheet for a secondary battery.

[12] In the gas adsorption sheet for a secondary battery with a cover film described in any one of [1] to

[11] above, the material constituting the heat-resistant substrate may be polyamideimide, polyetherimide, polyphenylene sulfide, polyethylene naphthalate, polyimide, or polyether ether ketone.

[13] In the gas adsorption sheet for a secondary battery with a cover film described in any one of [1] to

[12] above, the cover film may include a substrate and a pressure-sensitive adhesive layer disposed on at least one side of the substrate.

[14] In the gas adsorption sheet for a secondary battery with a cover film according to the above item

[13] , the pressure-sensitive adhesive layer may be formed from a pressure-sensitive adhesive containing a base polymer, and the content of structural units derived from an organic acid monomer may be preferably 0.5 parts by weight or less per 100 parts by weight of the base polymer.

[15] In the gas adsorption sheet for a secondary battery with a cover film according to any one of items [1] to

[14] , the cover film may be peelable.

[16] An all-solid-state secondary battery according to an embodiment of the present invention comprises the gas adsorption sheet for a secondary battery with a cover film according to any one of items [1] to

[15] .

[17] An all-solid-state secondary battery using a sulfide-based solid electrolyte according to an embodiment of the present invention comprises the gas adsorption sheet for a secondary battery with a cover film according to any one of items [1] to

[15] .

[0006] According to the present invention, it is possible to provide a gas adsorbent sheet that can preferably adsorb sulfide gases.

[0007] 1 is a schematic cross-sectional view of a gas adsorbent sheet for a secondary battery according to one embodiment of the present invention.

[0008] A. Overall Configuration of a Gas Adsorbent Sheet for a Secondary Battery with a Cover Film FIG. 1 is a schematic cross-sectional view of a gas adsorbent sheet for a secondary battery with a cover film (hereinafter simply referred to as a gas adsorbent sheet with a cover film) according to one embodiment of the present invention. The gas adsorbent sheet with a cover film 100 includes a gas adsorbent sheet for a secondary battery (hereinafter simply referred to as a gas adsorbent sheet) 110 including a heat-resistant substrate 10 and a gas adsorbing layer 20 disposed on at least one side of the heat-resistant substrate 10, and a cover film 120 disposed on the side of the gas adsorbing layer 20 opposite the heat-resistant substrate 10. The gas adsorbing layer includes a binder resin and gas adsorbing particles. The gas adsorbing particles are composed of an inorganic porous material having pores. In this specification, gas adsorbing particles are particles that can adsorb sulfide gases by chemical adsorption and exhibit gas adsorption performance. An example of a sulfide gas is hydrogen sulfide. In one embodiment, the gas adsorption sheet 110 further includes an intermediate layer 30 between the heat-resistant substrate 10 and the gas adsorption layer 20. The formation of the intermediate layer can prevent the gas adsorption layer from falling off. In another embodiment, the cover film 120 includes a substrate 41 and a pressure-sensitive adhesive layer 51 disposed on at least one side of the substrate 41. The pressure-sensitive adhesive layer 51 can be laminated so as to face the gas adsorption layer 20. The gas adsorption sheet with a cover film and the gas adsorption sheet may include any other appropriate layer as long as the effects of the present invention are achieved. For example, the gas adsorption sheet may include a pressure-sensitive adhesive layer disposed on one or both outer surfaces thereof (not shown).

[0009] According to an embodiment of the present invention, a gas adsorption sheet that is easy to handle and applicable to various applications can be obtained by dispersing gas adsorption particles in a binder resin, forming a gas adsorption layer composed of the gas adsorption particles and the binder resin, and forming the sheet. Furthermore, by providing a heat-resistant substrate, the effect of improving handleability becomes even more pronounced. Furthermore, by using a heat-resistant substrate as the substrate, the gas adsorption sheet can be heated (e.g., heated at 200°C for 24 hours) before use. Heating before use can remove unnecessary substances adhering to the gas adsorption particles, allowing the gas adsorption particles to fully exhibit their performance during use.

[0010] The gas adsorption sheet can be suitably used, for example, as a gas adsorbent for an all-solid-state battery. The gas adsorption sheet has the advantage that it can absorb even trace amounts of sulfide gases with a high absorption rate and with little re-release.

[0011] Furthermore, by providing the cover film, the gas adsorption sheet with the cover film can prevent the gas adsorption layer from being detached, damaged, etc., and the performance of the gas adsorption particles can be favorably exhibited. The gas adsorption sheet with the cover film can be used as a gas adsorption sheet by peeling off the cover film.

[0012] B. Gas adsorption sheet H of the above gas adsorption sheet ２ The S adsorption amount is preferably 10 mg / g or more, more preferably 30 mg / g or more, even more preferably 50 mg / g or more, particularly preferably 80 mg / g or more, and most preferably 100 mg / g or more. ２ The upper limit of the S adsorption amount is, for example, 500 mg / g, preferably 800 mg / g, and more preferably 1000 mg / g. ２ The method for measuring the amount of adsorbed sulfur will be described later.

[0013] The gas adsorption sheet may have adhesiveness on one or both sides, or may be a gas adsorption sheet without adhesiveness. Examples of the gas adsorption sheet having adhesiveness include a gas adsorption layer having adhesiveness, and a gas adsorption sheet having an adhesive layer disposed on the outermost surface thereof.

[0014] When the gas adsorption sheet has adhesive properties, the adhesive strength of the gas adsorption sheet to a stainless steel plate at 23°C is preferably 0.1 N / 19 mm to 30 N / 19 mm, more preferably 0.5 N / 19 mm to 20 N / 19 mm. Within these ranges, the gas adsorption sheet can be suitable for battery applications. In this specification, adhesive strength refers to adhesive strength measured by a method in accordance with JIS Z 0237:2000, in which an adhesive tape is applied to an adherend (SUS304BA) by rolling a 2 kg roller back and forth once, and the adhesive tape is left to stand at 25°C for 30 minutes, and then peeled off at a peel angle of 180° and a peel rate (tensile speed) of 300 mm / min.

[0015] The thickness of the gas adsorption sheet is preferably 10 μm to 1000 μm, more preferably 20 μm to 500 μm, even more preferably 20 μm to 150 μm, still more preferably 20 μm to 120 μm, and particularly preferably 20 μm to 110 μm. Within these ranges, a gas adsorption sheet with excellent gas adsorption performance and handleability can be obtained.

[0016] B-1. Gas Adsorption Layer As described above, the gas adsorption layer contains a binder resin and gas adsorption particles dispersed in the binder resin. In the present invention, this configuration makes it possible to form the gas adsorption layer by coating using a coating liquid containing the binder resin and the gas adsorption particles. As a result, a gas adsorption layer with excellent dispersibility of the gas adsorption particles can be formed, and a gas adsorption sheet with excellent gas adsorption performance can be obtained.

[0017] The thickness of the gas adsorption layer is preferably 5 μm to 150 μm, more preferably 5 μm to 100 μm, and even more preferably 10 μm to 80 μm. Within this range, the gas adsorption layer can fully exhibit the performance of the gas adsorption particles. Furthermore, a gas adsorption sheet with excellent handleability can be obtained.

[0018] (Gas-adsorbing particles) As described above, the gas-adsorbing particles can adsorb sulfide-based gases by chemical adsorption. Chemical adsorption refers to adsorbing a target gas through a chemical reaction. The gas-adsorbing particles are made of an inorganic porous material having pores. In one embodiment, the gas-adsorbing particles may be a composite of a silicate and at least one metal salt selected from copper, zinc, manganese, cobalt, and nickel.

[0019] Preferably, copper, zinc, or manganese is used as the metal (metal ion) constituting the metal salt, and more preferably copper or zinc. By using these metals, a gas adsorption sheet with particularly excellent adsorption properties for sulfide-based gases can be obtained. Furthermore, a gas adsorption sheet can be provided that can be easily determined as to whether it has been used or not by the coloring after gas adsorption. Examples of acids that form the metal salt include sulfuric acid, hydrochloric acid, and nitric acid.

[0020] The silicate is preferably an alkali metal silicate, more preferably sodium silicate or potassium silicate, and particularly preferably sodium silicate.

[0021] The molar ratio of the metal salt to the silicate (metal salt / silicate) is preferably 0.29 or more and less than 0.5, more preferably 0.3 to 0.45, and even more preferably 0.3 to 0.4.

[0022] In one embodiment, the gas-adsorbing particles have a surface-treated surface. The surface treatment may be a treatment for adjusting the affinity between the gas-adsorbing particles and the binder resin. By using gas-adsorbing particles having a surface-treated surface, a gas-adsorbing layer having excellent mechanical strength and resistance to shedding can be formed. The gas-adsorbing sheet with a cover film laminated thereon is particularly preferred in that damage to the gas-adsorbing layer can be prevented when the cover film is peeled off during use of the gas-adsorbing sheet. Furthermore, by using gas-adsorbing particles having a surface-treated surface, a gas-adsorbing sheet having excellent processability during cutting can be obtained. For example, damage to the gas-adsorbing layer can be prevented when punching the gas-adsorbing sheet with a blade such as a Thomson blade. The surface-treated surface may be the entire surface of the gas-adsorbing particles, or a portion of the surface. Examples of surface treatments include silane coupling agent treatment, isocyanate compound treatment, thiol compound treatment, acid compound treatment, alcohol compound treatment, and epoxy compound treatment. In one embodiment, the surface treatment may be a coupling treatment. The use of coupling-treated gas adsorbent particles significantly prevents the gas adsorbed layer from being separated and improves processability.

[0023] In one embodiment, gas adsorption particles having a surface treated with silicone are used. In one embodiment, the silicone has an ethoxysilane group or a methoxysilane group. Use of such a silicone allows for the formation of a gas adsorption layer that is excellent in mechanical strength and resistant to shedding. The silicone may be a silane coupling agent. Preferably, the silane coupling agent contains an epoxy group and / or an amino group. Use of such a silane coupling agent allows for the formation of a gas adsorption layer that is excellent in mechanical strength and resistant to shedding. The gas adsorption particles, i.e., gas adsorption particles surface-treated with silicone (silane coupling agent), can be obtained by contacting the silane coupling agent with the gas adsorption particle surface to react organic groups (e.g., hydroxyl groups) present on the surface with silanol groups generated by hydrolysis of the silane coupling agent, or by bonding oligomers generated by condensation of the silanol groups to the gas adsorption particles.

[0024] Examples of the silane coupling agent include vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, N-2-(aminoethyl)-3-amino N-propylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, N-(vinylbenzyl)-2-aminopropyltrimethoxysilane hydrochloride, tris-(trimethoxysilylpropyl)isocyanurate, 3-ureidopropyltrialkoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-isocyanatopropyltriethoxysilane, dithioltriazinepropyltriethoxysilane, and the like.

[0025] In one embodiment, the silicone may be an alkoxysilane such as phenyltrimethoxysilane; an organosilazane compound such as hexamethyldisilazane; or the like.

[0026] The average particle size (median size D50) of the gas-adsorbed particles is preferably 10 μm or less. Within this range, a gas-adsorbed layer with a high gas adsorption capacity can be formed. The average particle size (median size D50) can be measured using a laser diffraction / scattering particle size distribution analyzer.

[0027] The pore volume of the gas adsorption particles is preferably 0.3 ml / g to 0.5 ml / g, and more preferably 0.35 ml / g to 0.45 ml / g. Within this range, a gas adsorption sheet with particularly excellent adsorption properties for sulfide gases can be obtained. The pore volume can be measured by the BET method using nitrogen gas.

[0028] The specific surface area of ​​the gas adsorption particles is preferably 100 m ２ / g to 3000m ２ / g. Within this range, gas-adsorbed particles having excellent gas adsorption performance and mechanical strength can be obtained. Gas-adsorbed particles having a large specific surface area are prone to aggregation, but according to the present invention, a gas-adsorbed layer can be formed with good dispersibility of the gas-adsorbed particles.

[0029] H of gas adsorbed particles ２ The S adsorption amount is preferably 10 mg / g or more, more preferably 30 mg / g or more, even more preferably 50 mg / g or more, particularly preferably 80 mg / g or more, and most preferably 100 mg / g or more. ２ The upper limit of the S adsorption amount is, for example, 500 mg / g, preferably 800 mg / g, and more preferably 1000 mg / g.

[0030] The content of the gas adsorption particles is preferably 10 to 90 parts by weight, more preferably 30 to 80 parts by weight, and even more preferably 40 to 70 parts by weight, relative to 100 parts by weight of the gas adsorption sheet. Within such a range, a gas adsorption sheet having excellent gas adsorption performance and easy handling can be obtained.

[0031] The content of the gas adsorption particles is preferably 10 to 2,000 parts by weight, more preferably 50 to 1,500 parts by weight, even more preferably 100 to 1,000 parts by weight, and particularly preferably 280 to 1,000 parts by weight, relative to 100 parts by weight of the binder resin constituting the gas adsorption layer. Within this range, a gas adsorption layer can be obtained from which the gas adsorption particles are difficult to desorb. Furthermore, a gas adsorption sheet with excellent gas adsorption performance and handleability can be obtained.

[0032] (Binder Resin) Any appropriate resin can be used as the binder resin as long as the effects of the present invention can be obtained. Examples of binder resins include acrylic resins; rubber-based resins such as butyl rubber, isoprene rubber, polyisobutylene rubber, and ethylene propylene rubber; silicone-based resins; urethane-based resins; epoxy-based resins; alkyd-based resins; polyester-based resins; melamine-based resins; polyamide-based resins; polyimide-based resins; ethylene-vinyl acetate copolymer resins; and polyvinyl alcohol-based resins. In one embodiment, acrylic resins, butyl rubber, or silicone-based resins are preferably used. Use of these resins makes it possible to form a gas adsorption layer that exhibits excellent dispersibility of gas adsorption particles.

[0033] The binder resin preferably has gas permeability. By using a binder resin having gas permeability, a gas adsorption sheet suitable for battery applications can be obtained. Examples of resins with excellent gas permeability include rubber-based resins such as acrylic resins, butyl rubber, isoprene rubber, polyisobutylene rubber, and ethylene propylene rubber, silicone-based resins, urethane-based resins, epoxy-based resins, alkyd-based resins, polyester-based resins, melamine-based resins, polyamide-based resins, and polyimide-based resins.

[0034] In one embodiment, an acrylic resin is used as the binder resin. The use of an acrylic resin makes it possible to form a gas adsorption layer from which gas adsorption particles are less likely to desorb. Furthermore, it is possible to form a gas adsorption layer from which the gas adsorption performance of the gas adsorption particles can be fully exhibited.

[0035] Examples of acrylic resins include acrylic resins containing one or more structural units derived from (meth)acrylic acid alkyl esters. The content of the structural units derived from (meth)acrylic acid alkyl esters is preferably 50 to 97 parts by weight, more preferably 70 to 94 parts by weight, per 100 parts by weight of the acrylic resin.

[0036] Preferably, the (meth)acrylic acid alkyl ester has a linear or branched alkyl group having 1 to 24 carbon atoms (more preferably 3 to 20, and even more preferably 6 to 18).

[0037] In one embodiment, the (meth)acrylic acid alkyl ester preferably has a linear or branched alkyl group having a carbon number of 4 to 12, and more preferably has a linear or branched alkyl group having a carbon number of 6 to 12. If a gas adsorption layer is formed using an acrylic resin having such a (meth)acrylic acid alkyl ester as a main structural unit, a gas adsorption sheet can be obtained that is suppressed from discoloring and swelling in an electrolyte solution.

[0038] Examples of the (meth)acrylic acid alkyl ester include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, and eicosyl (meth)acrylate.

[0039] In one embodiment, a (meth)acrylic acid alkyl ester having a branched alkyl group is used as the (meth)acrylic acid alkyl ester. By using a (meth)acrylic acid alkyl ester having a branched alkyl group, a gas adsorption layer can be formed that can fully exhibit the gas adsorption performance of the gas adsorption particles. A (meth)acrylic acid alkyl ester having a linear alkyl group and a (meth)acrylic acid alkyl ester having a branched alkyl group may be used in combination. Furthermore, a (meth)acrylic acid alkyl ester having a branched alkyl group may be used alone as the (meth)acrylic acid alkyl ester.

[0040] In one embodiment, in the acrylic resin, the content of the structural units derived from a (meth)acrylic acid alkyl ester having a branched alkyl group is preferably 20 to 100 parts by weight, more preferably 30 to 100 parts by weight, even more preferably 50 to 100 parts by weight, and particularly preferably 70 to 100 parts by weight, per 100 parts by weight of the structural units derived from a (meth)acrylic acid alkyl ester (i.e., 100 parts by weight of the total amount of the (meth)acrylic acid alkyl ester having a linear alkyl group (including methyl (meth)acrylate and ethyl (meth)acrylate) and the (meth)acrylic acid alkyl ester having a branched alkyl group).

[0041] Examples of (meth)acrylic acid alkyl esters having a branched alkyl group include isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, isononyl (meth)acrylate, isodecyl (meth)acrylate, stearyl (meth)acrylate, 2-ethylbutyl (meth)acrylate, and 2-methylbutyl (meth)acrylate. Of these, 2-ethylhexyl (meth)acrylate is preferred.

[0042] The acrylic resin may contain, as necessary, a structural unit derived from another monomer copolymerizable with the alkyl (meth)acrylate, for the purpose of modifying properties such as cohesive strength, heat resistance, and crosslinkability. Examples of such other monomers include carboxyl group-containing monomers such as (meth)acrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid; acid anhydride group-containing monomers such as maleic anhydride and itaconic anhydride; phosphoric acid group-containing monomers such as 2-hydroxyethyl acryloyl phosphate; sulfonic acid group-containing monomers such as styrenesulfonic acid, allylsulfonic acid, 2-(meth)acrylamido-2-methylpropanesulfonic acid, (meth)acrylamidopropanesulfonic acid, sulfopropyl (meth)acrylate, and (meth)acryloyloxynaphthalenesulfonic acid; hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, hydroxyhexyl (meth)acrylate, hydroxyoctyl (meth)acrylate, hydroxydecyl (meth)acrylate, hydroxylauryl (meth)acrylate, and (4-hydroxymethylcyclohexyl)methyl methacrylate. hydroxyl group-containing monomers; (N-substituted) amide monomers such as (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N-butyl(meth)acrylamide, N-methylol(meth)acrylamide, and N-methylolpropane(meth)acrylamide; aminoalkyl (meth)acrylate monomers such as aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, and t-butylaminoethyl (meth)acrylate; methoxyethyl (meth)acrylate, (Meth)acrylate alkoxyalkyl monomers such as ethoxyethyl (meth)acrylate; maleimide monomers such as N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, and N-phenylmaleimide; itaconimide monomers such as N-methylitaconimide, N-ethylitaconimide, N-butylitaconimide, N-octylitaconimide, N-2-ethylhexylitaconimide, N-cyclohexylitaconimide, and N-laurylitaconimide;succinimide-based monomers such as N-(meth)acryloyloxymethylene succinimide, N-(meth)acryloyl-6-oxyhexamethylene succinimide, and N-(meth)acryloyl-8-oxyoctamethylene succinimide; vinyl-based monomers such as vinyl acetate, vinyl propionate, N-vinylpyrrolidone, methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole, vinylmorpholine, N-vinylcarboxylic acid amides, styrene, α-methylstyrene, and N-vinylcaprolactam; cyanoacrylate monomers such as acrylonitrile and methacrylonitrile; epoxy group-containing acrylic monomers such as glycidyl (meth)acrylate; polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, methoxyethylene glycol (meth)acrylate, and (meth)acrylate. Examples of suitable monomers include glycol-based acrylic ester monomers such as methoxypolypropylene glycol acrylate; acrylic ester monomers having heterocycles, halogen atoms, silicon atoms, etc., such as tetrahydrofurfuryl (meth)acrylate, fluorine (meth)acrylate, and silicone (meth)acrylate; polyfunctional monomers such as hexanediol di(meth)acrylate, (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, epoxy acrylate, polyester acrylate, and urethane acrylate; olefin-based monomers such as isoprene, butadiene, and isobutylene; and vinyl ether-based monomers such as vinyl ether. These monomer components may be used alone or in combination of two or more.

[0043] The content of the structural units derived from the other monomers is preferably 20 parts by weight or less, more preferably 15 parts by weight or less, and even more preferably 1 to 10 parts by weight, relative to 100 parts by weight of the acrylic resin.

[0044] In one embodiment, the acrylic resin does not contain a structural unit derived from a carboxyl group-containing monomer such as (meth)acrylic acid. By using such an acrylic resin, it is possible to preferably form a gas adsorption layer while preventing gelation even when the gas adsorption particles are contained.

[0045] The weight-average molecular weight of the acrylic resin is preferably 300,000 to 2,000,000, and more preferably 500,000 to 1,500,000. The weight-average molecular weight can be measured by GPC (solvent: THF).

[0046] B-2. Heat-Resistant Substrate In this specification, a heat-resistant substrate refers to a substrate that can withstand heating for 24 hours in an atmosphere at a temperature of 150°C and a pressure of -100 kPa to 0 kPa (preferably, 24 hours in an atmosphere at a temperature of 200°C and a pressure of -100 kPa to 0 kPa), and specifically refers to a substrate that undergoes a dimensional change of 5% or less when heated for 24 hours in an atmosphere at a temperature of 150°C and a pressure of -100 kPa (preferably, 24 hours in an atmosphere at a temperature of 200°C and a pressure of -100 kPa). Furthermore, when the heat-resistant substrate is formed from a resin, the heat-resistant substrate refers to a substrate made of a resin having a glass transition temperature of 80°C or higher (preferably, 100°C or higher, more preferably, 150°C or higher). The term "glass transition temperature" refers to the temperature at which the loss tangent (tan δ) peaks when measured by the DMA method (tensile method) under the following conditions: a temperature rise rate of 5°C / min, a sample width of 5 mm, a chuck distance of 20 mm, and a frequency of 10 Hz.

[0047] Any suitable material can be used as the material for the heat-resistant substrate as long as the effects of the present invention can be obtained. Preferably, the heat-resistant substrate is made of a resin. Examples of materials for the heat-resistant substrate include polyamideimide (PAI), polyetherimide (PEI), polyphenylene sulfide (PPS), polyethylene naphthalate (PEN), polyimide (PI), and polyether ether ketone (PEEK). These resins have excellent heat resistance.

[0048] The thickness of the heat-resistant substrate is preferably 5 μm to 500 μm, more preferably 10 μm to 300 μm, and even more preferably 15 μm to 100 μm. Within such a range, a gas adsorbent sheet with particularly excellent handleability can be obtained.

[0049] B-3. ​​Intermediate Layer The intermediate layer contains any appropriate resin. Examples of resins forming the intermediate layer include acrylic resins, rubber resins, and silicone resins. Among these, acrylic resins are preferably used. Furthermore, an active energy ray-curable acrylic resin may be used as the adhesive. Examples of resins forming the intermediate layer include the binder resins described above. In one embodiment, the resin forming the intermediate layer is the same as the binder resin forming the gas adsorption layer. The intermediate layer does not contain gas adsorption particles.

[0050] By forming the intermediate layer, it is possible to obtain a gas adsorbing sheet in which the gas adsorbing layer is less likely to desorb.

[0051] The thickness of the intermediate layer is preferably 1 μm to 50 μm, more preferably 2 μm to 30 μm, and even more preferably 2 μm to 20 μm.

[0052] The intermediate layer may contain any appropriate additives as needed, such as a crosslinking agent, a tackifier, a plasticizer (e.g., a trimellitic ester-based plasticizer or a pyromellitic ester-based plasticizer), a pigment, a dye, a filler, an antioxidant, a conductive agent, an ultraviolet absorber, a light stabilizer, a release adjuster, a softener, a surfactant, a flame retardant, an antioxidant, and a solvent.

[0053] C. Method for Manufacturing Gas Adsorption Sheet The gas adsorption sheet can be manufactured by any appropriate method. In one embodiment, the gas adsorption sheet is manufactured by coating (applying and drying) a gas adsorption layer-forming composition containing the binder resin and gas adsorption particles on a heat-resistant substrate. Forming a gas adsorption layer by coating can provide a gas adsorption sheet with excellent dispersibility of the gas adsorption particles and excellent gas adsorption performance.

[0054] The gas-adsorbing layer-forming composition may further contain any suitable additives in addition to the binder resin and gas-adsorbing particles. Examples of additives include crosslinkers, tackifiers, plasticizers (e.g., trimellitate ester-based plasticizers, pyromellitate ester-based plasticizers), pigments, dyes, fillers, antioxidants, conductive agents, UV absorbers, light stabilizers, release modifiers, softeners, surfactants, flame retardants, and antioxidants. Examples of crosslinkers include isocyanate-based crosslinkers, epoxy-based crosslinkers, melamine-based crosslinkers, and peroxide-based crosslinkers, as well as urea-based crosslinkers, metal alkoxide-based crosslinkers, metal chelate-based crosslinkers, metal salt-based crosslinkers, carbodiimide-based crosslinkers, oxazoline-based crosslinkers, aziridine-based crosslinkers, and amine-based crosslinkers. Among these, isocyanate-based crosslinkers and epoxy-based crosslinkers are preferred. The gas-adsorbing layer-forming composition may also contain a solvent such as toluene or ethyl acetate.

[0055] Examples of methods for applying the gas adsorption layer-forming composition include coating methods such as air doctor coating, blade coating, knife coating, reverse coating, transfer roll coating, gravure roll coating, kiss coating, cast coating, spray coating, slot orifice coating, calendar coating, electrodeposition coating, dip coating, and die coating; and printing methods such as relief printing methods such as flexographic printing, intaglio printing methods such as direct gravure printing and offset gravure printing, lithographic printing methods such as offset printing, and stencil printing methods such as screen printing.

[0056] D. Cover Film In one embodiment, the cover film includes a substrate and a pressure-sensitive adhesive layer disposed on at least one side of the substrate.

[0057] In one embodiment, the cover film is disposed in a releasable manner. In one embodiment, the cover film is releasable from the gas adsorption sheet after heat drying at 110°C for 3 hours. The releasability of such a cover film can be controlled by adjusting the adhesive strength of the cover film, for example, by adjusting the composition of the adhesive layer.

[0058] The adhesive strength of the cover film to a stainless steel plate at 25°C is preferably 0.05 N / 20 mm to 5 N / 20 mm, more preferably 0.1 N / 20 mm to 3 N / 20 mm, more preferably 0.15 N / 20 mm to 2 N / 20 mm, and even more preferably 0.15 N / 20 mm to 1 N / 20 mm.

[0059] In one embodiment, the cover film is laminated so as to be releasable from the gas adsorption sheet. The gas adsorption sheet with the cover film is dried at 130°C under a reduced pressure of -100 kPa for 3 hours, and then the peel strength when peeling the cover film from the gas adsorption sheet is preferably 0.01 N / 50 mm to 5 N / 50 mm, more preferably 0.02 N / 50 mm to 3 N / 50 mm, and even more preferably 0.05 N / 50 mm to 2.5 N / 50 mm. Within these ranges, the cover film can be peeled while preventing damage to the gas absorption layer. The peel strength can be measured using a method in accordance with JIS Z 0237:2000. That is, the peel strength is measured by peeling the cover film of the gas adsorption sheet with the cover film from the gas adsorption sheet under the following conditions: a measurement temperature of 25°C, a peel angle of 180°, and a peel rate (tensile speed) of 300 mm / min.

[0060] D-1. Substrate The substrate can be made of any appropriate material. Various sheet-like materials can be used as the substrate, such as resin film, paper, cloth, nonwoven fabric, metal foil, or plastic laminates thereof, or laminates of plastics. Among these, resin film is most preferable from the standpoints of handleability and cost. The material constituting the resin film can be selected as needed from the standpoints of strength, heat resistance, and the like. Examples include olefin-based resins containing α-olefins as monomer components, such as polyethylene (PE), polypropylene (PP), ethylene-propylene copolymer, and ethylene-vinyl acetate copolymer (EVA); polyesters such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polybutylene terephthalate (PBT); polyvinyl chloride (PVC); polyphenylene sulfide (PPS); amide-based resins such as polyamide (nylon) and wholly aromatic polyamide (aramid); polyether ether ketone (PEEK), polyimide, polyetherimide, polystyrene, and acrylic resin. These materials can be used alone or in combination of two or more. The plastic film may be any of an unstretched film, a uniaxially oriented film, and a biaxially oriented film. These films may be laminated films consisting of two or more film layers, or may contain a lubricant such as inert particles added thereto for ease of handling.

[0061] The thickness of the substrate is preferably 200 μm or less, more preferably 1 μm to 200 μm, even more preferably 5 μm to 100 μm, particularly preferably 10 μm to 100 μm, particularly preferably 20 μm to 100 μm, and most preferably 30 μm to 100 μm. Within such a range, lifting is prevented when the substrate is formed into a roll, and a gas adsorbent sheet with a cover film that is easy to work with can be obtained.

[0062] The moisture permeability of the substrate is preferably 500 g / m ２ 24 hours or less, more preferably 100 g / m ２The moisture permeability can be determined in accordance with the moisture permeability test (cup method) of JIS Z0208.

[0063] The substrate may be subjected to a surface treatment, such as corona treatment, chromic acid treatment, ozone exposure, flame exposure, high-voltage shock exposure, ionizing radiation treatment, or coating with a primer.

[0064] The thickness of the pressure-sensitive adhesive layer is preferably 30 μm or less, more preferably 20 μm or less, and even more preferably 10 μm or less. The lower limit of the pressure-sensitive adhesive layer thickness is, for example, 1 μm (preferably 0.5 μm).

[0065] The pressure-sensitive adhesive layer includes any suitable pressure-sensitive adhesive. Any suitable pressure-sensitive adhesive can be used as the pressure-sensitive adhesive as long as the effects of the present invention can be obtained. For example, a pressure-sensitive adhesive can be used as the pressure-sensitive adhesive.

[0066] Examples of pressure-sensitive adhesives include acrylic adhesives, rubber adhesives, vinyl alkyl ether adhesives, silicone adhesives, polyester adhesives, polyamide adhesives, urethane adhesives, and styrene-diene block copolymer adhesives. Among these, acrylic adhesives or rubber adhesives are preferred, and acrylic adhesives are even more preferred. The above-mentioned adhesives may be used alone or in combination of two or more. In one embodiment, from the viewpoint of ultraviolet absorption, an adhesive containing a base polymer having an aromatic ring and / or a double bond is used. From this perspective, acrylic adhesives may be preferably used.

[0067] Examples of the acrylic adhesive include an acrylic adhesive having as a base polymer an acrylic polymer (homopolymer or copolymer) using one or more (meth)acrylic acid alkyl esters as a monomer component. Specific examples of the (meth)acrylic acid alkyl ester include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, and methyl (meth)acrylate. Examples of (meth)acrylic acid C1-20 alkyl esters include nonyl acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, nonadecyl (meth)acrylate, and eicosyl (meth)acrylate. Of these, (meth)acrylic acid alkyl esters having a linear or branched alkyl group having 4 to 18 carbon atoms can be preferably used.

[0068] The acrylic polymer may contain, as necessary, units corresponding to other monomer components copolymerizable with the alkyl (meth)acrylate, for the purpose of modifying properties such as cohesive strength, heat resistance, and crosslinkability. Examples of such monomer components include carboxyl group-containing monomers such as acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid; acid anhydride monomers such as maleic anhydride and itanoic anhydride; hydroxyl group-containing monomers such as hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, hydroxyhexyl (meth)acrylate, hydroxyoctyl (meth)acrylate, hydroxydecyl (meth)acrylate, hydroxylauryl (meth)acrylate, and (4-hydroxymethylcyclohexyl)methyl methacrylate; sulfonic acid group-containing monomers such as styrenesulfonic acid, allylsulfonic acid, 2-(meth)acrylamido-2-methylpropanesulfonic acid, (meth)acrylamidopropanesulfonic acid, sulfopropyl (meth)acrylate, and (meth)acryloyloxynaphthalenesulfonic acid; (N-substituted) amide monomers such as methylol (meth) acrylamide, N,N-dimethyl (meth) acrylamide, N-butyl (meth) acrylamide, N-methylol (meth) acrylamide, and N-methylol propane (meth) acrylamide; aminoalkyl (meth) acrylate monomers such as aminoethyl (meth) acrylate, N,N-dimethylaminoethyl (meth) acrylate, and t-butylaminoethyl (meth) acrylate; alkoxyalkyl (meth) acrylate monomers such as methoxyethyl (meth) acrylate and ethoxyethyl (meth) acrylate; maleimide monomers such as N-cyclohexyl maleimide, N-isopropyl maleimide, N-lauryl maleimide, and N-phenyl maleimide; itaconimide monomers such as N-methyl itaconimide, N-ethyl itaconimide, N-butyl itaconimide, N-octyl itaconimide, N-2-ethylhexyl itaconimide, N-cyclohexyl itaconimide, and N-lauryl itaconimide;succinimide-based monomers such as N-(meth)acryloyloxymethylene succinimide, N-(meth)acryloyl-6-oxyhexamethylene succinimide, and N-(meth)acryloyl-8-oxyoctamethylene succinimide; vinyl-based monomers such as vinyl acetate, vinyl propionate, N-vinylpyrrolidone, methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole, vinylmorpholine, N-vinylcarboxylic acid amides, styrene, α-methylstyrene, and N-vinylcaprolactam; cyanoacrylate monomers such as acrylonitrile and methacrylonitrile; epoxy group-containing acrylic monomers such as glycidyl (meth)acrylate; polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, methoxyethylene glycol (meth)acrylate, and (meth)acrylate. Examples of suitable monomers include glycol-based acrylic ester monomers such as methoxypolypropylene glycol acrylate; acrylic ester monomers having heterocycles, halogen atoms, silicon atoms, etc., such as tetrahydrofurfuryl (meth)acrylate, fluorine (meth)acrylate, and silicone (meth)acrylate; polyfunctional monomers such as hexanediol di(meth)acrylate, (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, epoxy acrylate, polyester acrylate, and urethane acrylate; olefin-based monomers such as isoprene, butadiene, and isobutylene; and vinyl ether-based monomers such as vinyl ether. These monomer components may be used alone or in combination of two or more.

[0069] In one embodiment, the content of structural units derived from organic acid monomers (e.g., (meth)acrylic acid group-containing monomers, carboxyl group-containing monomers) in the base polymer (e.g., acrylic polymer) is preferably 0.5 parts by weight or less, more preferably 0.3 parts by weight or less, per 100 parts by weight of the base polymer. Within this range, a cover film can be obtained that is less likely to destroy the gas adsorption layer of the gas adsorption sheet when peeled from the gas adsorption sheet. This effect is particularly pronounced when surface-treated (preferably coupling-treated) gas adsorption particles are used. In one embodiment, an acrylic polymer that does not contain structural units derived from organic acid monomers is used.

[0070] In one embodiment, the content of the nitrogen-containing monomer-derived structural unit in the base polymer (e.g., acrylic polymer) is preferably 20 parts by weight or less, and more preferably 15 parts by weight or less, per 100 parts by weight of the base polymer. Within this range, a cover film can be obtained that is less likely to destroy the gas adsorption layer of the gas adsorption sheet when peeled from the gas adsorption sheet.

[0071] The pressure-sensitive adhesive may contain any suitable additives as needed, such as crosslinkers, tackifiers (e.g., rosin-based tackifiers, terpene-based tackifiers, hydrocarbon-based tackifiers, etc.), plasticizers (e.g., trimellitate ester-based plasticizers, pyromellitate ester-based plasticizers), pigments, dyes, antioxidants, conductive materials, antistatic agents, light stabilizers, release modifiers, softeners, surfactants, flame retardants, antioxidants, ultraviolet absorbers, particles, etc.

[0072] Examples of the crosslinking agent include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, melamine-based crosslinking agents, peroxide-based crosslinking agents, urea-based crosslinking agents, metal alkoxide-based crosslinking agents, metal chelate-based crosslinking agents, metal salt-based crosslinking agents, carbodiimide-based crosslinking agents, oxazoline-based crosslinking agents, aziridine-based crosslinking agents, and amine-based crosslinking agents. Among these, isocyanate-based crosslinking agents and epoxy-based crosslinking agents are preferred. In one embodiment, from the viewpoint of ultraviolet absorption, a crosslinking agent having an aromatic ring and / or a double bond (e.g., an aromatic isocyanate-based crosslinking agent) is used.

[0073] Specific examples of the isocyanate-based crosslinking agent include lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate; alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate and isophorone diisocyanate; aromatic isocyanates such as 2,4-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate and xylylene diisocyanate; and isocyanate adducts such as trimethylolpropane / tolylene diisocyanate trimer adduct (manufactured by Tosoh Corporation, trade name "Coronate L"), trimethylolpropane / hexamethylene diisocyanate trimer adduct (manufactured by Tosoh Corporation, trade name "Coronate HL"), and isocyanurate of hexamethylene diisocyanate (manufactured by Tosoh Corporation, trade name "Coronate HX"). The content of the isocyanate-based crosslinking agent can be set to any appropriate amount depending on the desired adhesive strength, and is typically 0.1 to 20 parts by weight, and more preferably 0.5 to 10 parts by weight, per 100 parts by weight of the base polymer.

[0074] Examples of the epoxy crosslinking agent include N,N,N',N'-tetraglycidyl-m-xylylenediamine, diglycidylaniline, 1,3-bis(N,N-glycidylaminomethyl)cyclohexane (manufactured by Mitsubishi Gas Chemical Company, Inc., trade name "Tetrad C"), 1,6-hexanediol diglycidyl ether (manufactured by Kyoeisha Chemical Co., Ltd., trade name "Epolite 1600"), neopentyl glycol diglycidyl ether (manufactured by Kyoeisha Chemical Co., Ltd., trade name "Epolite 1500NP"), ethylene glycol diglycidyl ether (manufactured by Kyoeisha Chemical Co., Ltd., trade name "Epolite 1500NP"), and ethylene glycol diglycidyl ether (manufactured by Kyoeisha Chemical Co., Ltd., trade name "Epolite 1500NP"). Licor diglycidyl ether (manufactured by Kyoeisha Chemical Co., Ltd., trade name "Epolite 40E"), propylene glycol diglycidyl ether (manufactured by Kyoeisha Chemical Co., Ltd., trade name "Epolite 70P"), polyethylene glycol diglycidyl ether (manufactured by NOF Corporation, trade name "Epiol E-400"), polypropylene glycol diglycidyl ether (manufactured by NOF Corporation, trade name "Epiol P-200"), sorbitol polyglycidyl ether (manufactured by Nagase ChemteX Corporation, trade name "Denacol") Examples of suitable crosslinking agents include glycerol polyglycidyl ether (manufactured by Nagase ChemteX Corporation, trade name "Denacol EX-314"), pentaerythritol polyglycidyl ether, polyglycerol polyglycidyl ether (manufactured by Nagase ChemteX Corporation, trade name "Denacol EX-512"), sorbitan polyglycidyl ether, trimethylolpropane polyglycidyl ether, adipic acid diglycidyl ester, o-phthalic acid diglycidyl ester, triglycidyl tris(2-hydroxyethyl)isocyanurate, resorcinol diglycidyl ether, bisphenol-S-diglycidyl ether, and epoxy resins having two or more epoxy groups in the molecule. The content of the epoxy crosslinking agent can be set at any appropriate amount depending on the desired adhesive strength, and is typically 0.01 to 10 parts by weight, and more preferably 0.03 to 5 parts by weight, per 100 parts by weight of the base polymer.

[0075] Examples of the tackifier include rosin-based resins (e.g., rosin ester resins), terpene-based resins (e.g., terpene-phenol copolymers (terpene-modified phenolic resins), hydrogenated terpene resins), coumarone-indene resins, alicyclic saturated hydrocarbon-based resins, petroleum-based resins (e.g., hydrocarbon-based petroleum resins such as aliphatic / aromatic copolymer petroleum resins and aromatic petroleum resins), and phenol-based resins. In one embodiment, from the viewpoint of ultraviolet absorption, a crosslinker having an aromatic ring and / or a double bond (e.g., rosin-based resin) is used. The content of the tackifier can be set to any appropriate amount depending on the desired adhesive strength, and is typically 1 to 50 parts by weight, more preferably 10 to 30 parts by weight, per 100 parts by weight of the base polymer.

[0076] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. Evaluation methods in the examples are as follows. In the examples, "parts" and "%" are by weight unless otherwise specified.

[0077] (1) Cover film peel strength (peel strength of cover film from gas adsorption layer) After drying for 3 hours at 130°C under reduced pressure of -100 kPa, the cover film was peeled from the gas adsorption layer of the gas adsorption sheet with cover film, and the peel strength was measured. Test speed: 300 mm / min Peel angle: 180° Measurement temperature: 25°C

[0078] (2) Cover film peelability The failure mode during the cover film peel test was evaluated. ◯: Peeling was possible at the interface between the cover film and the gas adsorption layer △: The surface layer of the gas adsorption layer was transferred to the cover film side ×: The entire gas adsorption layer was transferred to the cover film side

[0079] (3) Gas adsorption layer strength After drying for 3 hours at 130°C under a reduced pressure of -100 kPa, the cover film was peeled off from the gas adsorption layer of the gas adsorption sheet (1) with the cover film, and a Nitto Denko No. 31B was attached to the exposed surface of the gas adsorption layer, and the peel strength was evaluated. Attachment conditions: 25°C environment, 1 round trip with a 2 kg roller, Test speed: 300 mm / min, Peel angle: 180°, Measurement temperature: 25°C

[0080] (4) Heat resistance The state of the gas adsorption sheet was confirmed after drying for 3 hours at 130°C under reduced pressure of -100 kPa. ◯: Sheet shape can be maintained ×: Sheet shape cannot be maintained

[0081] (5) Adhesion of Gas Adsorption Layer When measuring the strength of the gas adsorption layer in (3) above, the failure mode was evaluated. ◯: Cohesive failure mode of the gas adsorption layer ×: Anchor failure mode of the gas adsorption layer

[0082] (6) Processability The gas adsorption sheet with cover film was punched using a Thomson blade (size 5 mm × 20 mm, blade thickness 0.7 mm, R: 0.2), and the state of the gas adsorption sheet was evaluated. ◯: No chipping in the gas adsorption layer Δ: No chipping in the gas adsorption layer, but lifting or peeling of the cover film ×: Chip in the gas adsorption layer

[0083] (7) Moisture resistance A gas adsorption sheet with a cover film was dried for 3 hours at 110°C under reduced pressure of -100 kPa in a dry room with a dew point temperature of -50°C and a room temperature of 23°C, and then stored in the dry room, and the change in moisture content due to moisture absorption was measured. ◯: A moisture content of 1% or less could be maintained for 8 hours or more in the dry room ×: A moisture content of 1% or less could not be maintained for 8 hours in the dry room Moisture content measurement method (Karl Fischer method) Moisture content: AQ-2100 manufactured by HIRANUMA

[0084] (8) Cover Film Adhesion The obtained cover film (1) was attached to a SUS304BA plate and peeled off to evaluate the peel strength. Attachment conditions: 25°C environment, 1 round trip with a 2 kg roller, Test speed: 300 mm / min, Peel angle: 180°, Peel angle: 180°, Measurement temperature: 25°C

[0085] (9) Handling Efficiency The handling property of the gas adsorbent sheet with the cover film was evaluated for any problems that occurred when the sheet was wound around a 3-inch core made of ABS resin. ◯: No problems ×: The absorbent layer easily fell off, or the sheet was thermally shrunk, or the gas adsorbent layer was scratched during transportation.

[0086] (10) Hydrogen Sulfide Gas Adsorption Evaluation The hydrogen sulfide gas adsorption properties of the gas adsorption sheet with cover film were evaluated using the following equipment and evaluation method. Test Equipment 1: Tedlar Bag (10 L for containing test gas) *hereinafter referred to as bag) 2: Detector tube (Gastec, models 4HM, 4M, 4 L) 3: Constant temperature bath (Fukushima Galilei, model FMU-263I) 4: Metering pump for air charging (Shibata Scientific, model MP-Σ300NII) 5: Electronic balance (Shimadzu, model ATX224) 6: Hydrogen sulfide cylinder (Sumitomo Chemical, 99.9% purity) 7: Air cylinder (Taiyo Nippon Sanso, grade G2) Evaluation Method: Static Method 1: The sample was dried at 130°C for 3 hours under atmospheric pressure. 2: The weighed sample was placed in a bag using an electronic balance, sealed, and any remaining air in the bag was evacuated. 3: A predetermined amount of air was introduced into the bag using a metering pump. 4: Hydrogen sulfide gas was injected into the bag using a gas-tight syringe to adjust the test gas to a predetermined concentration (340 ppm). 5: The bag was left standing in a thermostatic chamber adjusted to a predetermined temperature and humidity (25°C, 0% RH). 6: After a predetermined time (24 hours) had passed, the bag was removed and the residual concentration in the bag was measured using a detector tube.

[0087] [Production Example 1] 2-ethylhexyl acrylate / ethyl acrylate / methyl methacrylate / hydroxyethyl acrylate (30 parts by weight / 70 parts by weight / 5 parts by weight / 4 parts by weight), 0.2 parts by weight of benzoyl peroxide as an initiator, and 244 parts by weight of toluene were charged into a four-neck flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser, and nitrogen gas was introduced while gently stirring. The liquid temperature in the flask was maintained at around 60°C, and a polymerization reaction was carried out for about 6 hours to obtain a resin composition (1) containing an acrylic copolymer (1).

[0088] [Production Example 2] 2-ethylhexyl acrylate / hydroxyethyl acrylate (100 parts by weight / 4 parts by weight), 0.2 parts by weight of an initiator (benzoyl peroxide), and 120 parts by weight of ethyl acetate were charged into a four-neck flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser, and nitrogen gas was introduced while gently stirring. The liquid temperature in the flask was maintained at around 60°C, and a polymerization reaction was carried out for about 6 hours to obtain a resin composition (2) containing an acrylic copolymer (2).

[0089] [Production Example 3] Butyl acrylate / 4-hydroxybutyl acrylate (99 parts by weight / 1 part by weight), 0.2 parts by weight of an initiator (benzoyl peroxide), and 120 parts by weight of ethyl acetate were charged into a four-neck flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser, and nitrogen gas was introduced while gently stirring. The liquid temperature in the flask was maintained at around 60°C, and a polymerization reaction was carried out for about 6 hours to obtain a resin composition (3) containing an acrylic copolymer (3).

[0090] [Production Example 4] Butyl acrylate / 4-hydroxybutyl acrylate / acrylic acid (97 parts by weight / 3 parts by weight / 0.2 parts by weight), 0.2 parts by weight of an initiator (benzoyl peroxide), and 120 parts by weight of ethyl acetate were charged into a four-neck flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser, and nitrogen gas was introduced while gently stirring. The liquid temperature in the flask was maintained at around 60°C, and a polymerization reaction was carried out for about 6 hours to obtain a resin composition (4) containing an acrylic copolymer (4).

[0091] [Production Example 5] 2-ethylhexyl acrylate / acrylic acid (95 parts by weight / 5 parts by weight), 0.2 parts by weight of an initiator (benzoyl peroxide), and 120 parts by weight of ethyl acetate were charged into a four-neck flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser, and nitrogen gas was introduced while gently stirring. The liquid temperature in the flask was maintained at around 60°C, and a polymerization reaction was carried out for about 6 hours to obtain a resin composition (5) containing an acrylic copolymer (5).

[0092] [Production Example 6] Production of heat-resistant substrate with intermediate layer To a resin composition (5) containing 100 parts by weight of the acrylic copolymer (5), 3 parts by weight of an isocyanate-based crosslinking agent (manufactured by Mitsui Chemicals, Inc., trade name "Takenate D-101E") and ethyl acetate were added to prepare an intermediate layer-forming composition (1) with a base of 18%. The obtained intermediate layer-forming composition (1) was coated onto a heat-resistant substrate (polyimide film, manufactured by Toray DuPont Co., Ltd., trade name "Kapton 100H", thickness: 25 μm) so that the thickness after drying would be 10 μm, and a heat-resistant substrate (1) with an intermediate layer was obtained.

[0093] [Production Example 7] Method for surface treatment of gas-adsorbed particles A four-neck flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser was charged with 100 parts by weight of Kesmon NS-20C (manufactured by Toagosei Co., Ltd.) as gas-adsorbed particles, 4 parts by weight of KBM-4803 (manufactured by Shin-Etsu Chemical Co., Ltd.) as a silane coupling agent, 150 parts by weight of tetrahydrofuran, and 1.3 parts by weight of distilled water, and nitrogen gas was introduced while gently stirring. The liquid temperature in the flask was maintained at around 60°C, and a coupling reaction was carried out for about 6 hours to obtain surface-treated particles (1).

[0094] [Production Example 8] Production of cover film (1) 3 parts by weight of an isocyanate-based crosslinking agent (manufactured by Mitsui Chemicals, Inc., trade name "Takenate D-101E") and ethyl acetate were added to a resin composition (3) containing 100 parts by weight of an acrylic copolymer (3) to prepare a 15% base adhesive layer-forming composition (1). The adhesive layer-forming composition (1) was applied to a 75 μm thick polyester film (manufactured by Toray Industries, Inc., trade name "Lumirror S10") so that the thickness after drying would be 10 μm, and a cover film (1) was obtained.

[0095] [Production Example 9] Production of cover film (2) A cover film (2) was obtained in the same manner as in Production Example 8, except that the adhesive layer-forming composition (1) was applied to a thickness of 20 µm.

[0096] [Production Example 10] Production of cover film (3) 3 parts by weight of an isocyanate-based crosslinking agent (manufactured by Mitsui Chemicals, Inc., trade name "Takenate D-101E") and ethyl acetate were added to a resin composition (4) containing 100 parts by weight of an acrylic copolymer (4) to prepare a 15% base adhesive layer-forming composition (2). The adhesive layer-forming composition (2) was applied to a 75 μm thick polyester film (manufactured by Toray Industries, Inc., trade name "Lumirror S10") so that the thickness after drying would be 10 μm, to obtain a cover film (3).

[0097] [Production Example 11] Production of cover film (4) A cover film (4) was obtained in the same manner as in Production Example 8, except that the thickness of the polyester film was 50 µm.

[0098] [Production Example 12] Production of cover film (5) A cover film (5) was obtained in the same manner as in Production Example 8, except that the thickness of the polyester film was 25 µm.

[0099] [Production Example 13] Production of cover film (6) 3 parts by weight of an isocyanate-based crosslinking agent (manufactured by Mitsui Chemicals, Inc., trade name "Takenate D-101E") and ethyl acetate were added to a resin composition (1) containing 100 parts by weight of an acrylic copolymer (1) to prepare a 15% base adhesive layer-forming composition (3). The adhesive layer-forming composition (3) was applied to a 50 μm thick polyester film (manufactured by Toray Industries, Inc., trade name "Lumirror S10") so that the thickness after drying would be 5 μm, to obtain a cover film (6).

[0100] Example 1 To a resin composition (1) containing 100 parts by weight of an acrylic copolymer (1), 3 parts by weight of an isocyanate-based crosslinking agent (manufactured by Mitsui Chemicals, Inc., trade name "Takenate D-101E"), ethyl acetate, and 900 parts by weight of hydrogen sulfide gas adsorbent particles (copper ion-supported silicate, manufactured by Toa Gosei, trade name "Kesmon NS-20C", average primary particle diameter D50: 10 μm or less) were added to prepare a 50% base gas adsorption layer-forming composition (1). The resulting gas adsorption layer-forming composition (1) was applied to a release-treated film (manufactured by Fujiko Co., Ltd., trade name "CA0", thickness: 75 μm) to a thickness of 60 μm after drying, thereby obtaining a gas adsorption layer (1). The resulting gas adsorption layer (1) was transferred to the intermediate layer of a heat-resistant substrate (1) with an intermediate layer, thereby obtaining a gas adsorption sheet (1). A cover film (1) was attached to the gas adsorption layer of the gas adsorption sheet (1) to obtain a gas adsorption sheet (1) with a cover film. The obtained gas adsorption sheet (1) with a cover film was subjected to the above-mentioned evaluations. The results are shown in Table 1.

[0101] [Examples 2 to 6] Gas adsorbent sheets with cover films were obtained in the same manner as in Example 1, except that the resin composition constituting the gas adsorbing layer, the blending amount of hydrogen sulfide gas adsorbing particles, the thickness of the gas adsorbing layer, and the type of cover film were as shown in Table 1. The obtained gas adsorbent sheets with cover films (1) were subjected to the above-mentioned evaluations. The results are shown in Table 1.

[0102] Comparative Example 1 A 50% base gas adsorption layer-forming composition was prepared by adding 3 parts by weight of an isocyanate-based crosslinking agent (manufactured by Mitsui Chemicals, Inc., trade name "Takenate D-101E"), ethyl acetate, and 900 parts by weight of hydrogen sulfide gas adsorbent particles (copper ion-supported silicate, manufactured by Toa Gosei Co., Ltd., trade name "Kesmon NS-20C", average primary particle diameter D50: 10 μm or less) to a resin composition (3) containing 100 parts by weight of acrylic copolymer (3). The gas adsorption layer-forming composition was applied to a heat-resistant substrate (polyimide film, manufactured by Toray DuPont Co., Ltd., trade name "Kapton 100H", thickness: 25 μm) to a thickness of 10 μm after drying, to obtain a gas adsorption sheet. The resulting gas adsorption sheet was subjected to the above-described evaluations. The results are shown in Table 2.

[0103] Comparative Example 2 To a resin composition (3) containing 100 parts by weight of an acrylic copolymer (3), 3 parts by weight of an isocyanate-based crosslinking agent (manufactured by Mitsui Chemicals, Inc., trade name "Takenate D-101E"), ethyl acetate, and 10 parts by weight of hydrogen sulfide gas adsorbent particles (copper ion-supported silicate, manufactured by Toa Gosei, trade name "Kesmon NS-20C", average primary particle diameter D50: 10 μm or less) were added to prepare a 50% base gas adsorption layer-forming composition. The resulting gas adsorption layer-forming composition was applied to a release-treated film (manufactured by Fujiko Co., Ltd., trade name "CA0", thickness: 75 μm) to a thickness of 80 μm after drying, thereby obtaining a gas adsorption layer. The resulting gas adsorption layer was transferred to the intermediate layer of the heat-resistant substrate (1) with an intermediate layer, thereby obtaining a gas adsorption sheet.

[0104] Comparative Example 3 To a resin composition (3) containing 100 parts by weight of an acrylic copolymer (3), 3 parts by weight of an isocyanate-based crosslinking agent (manufactured by Mitsui Chemicals, Inc., trade name "Takenate D-101E"), ethyl acetate, and 250 parts by weight of hydrogen sulfide gas adsorbent particles (copper ion-supported silicate, manufactured by Toa Gosei, trade name "Kesmon NS-20C", average primary particle diameter D50: 10 μm or less) were added to prepare a 50% base gas adsorption layer-forming composition. The resulting gas adsorption layer-forming composition was applied to a release-treated film (manufactured by Fujiko Co., Ltd., trade name "CA0", thickness: 75 μm) so that the thickness after drying was 80 μm, obtaining a gas adsorption layer. The resulting gas adsorption layer was transferred to the intermediate layer of the heat-resistant substrate (1) with an intermediate layer to obtain a gas adsorption sheet.

[0105] Comparative Example 4 A gas adsorption sheet was obtained in the same manner as in Comparative Example 2, except that 900 parts by weight of Molecular Sieve 5A (manufactured by Union Showa Co., Ltd.) was used instead of 10 parts by weight of hydrogen sulfide gas adsorption particles (copper ion-supported silicate, manufactured by Toagosei, trade name "Kesmon NS-20C", average primary particle diameter D50: 10 μm or less).

[0106]

[0107]

[0108] The gas adsorbent sheet of the present invention can be suitably used as a gas adsorbent for non-aqueous secondary batteries.

[0109] REFERENCE SIGNS LIST 10 heat-resistant substrate 20 gas adsorption layer 30 intermediate layer 110 gas adsorption sheet 120 cover film 100 gas adsorption sheet with cover film

Claims

1. A gas adsorption sheet for a secondary battery, comprising a heat-resistant substrate and a gas adsorption layer disposed on at least one side of the heat-resistant substrate, and a cover film disposed on the side of the gas adsorption layer opposite to the heat-resistant substrate, wherein the gas adsorption layer is composed of a binder resin and an inorganic porous material having pores, and contains gas adsorption particles capable of adsorbing gas.

2. The gas adsorption sheet for a secondary battery with a cover film according to claim 1, further comprising an intermediate layer between the heat-resistant substrate and the gas adsorption layer.

3. The gas adsorption particles are a composite of at least one metal salt selected from copper, zinc, manganese, cobalt, and nickel and a silicate, and the pore volume of the gas adsorption particles is preferably 0.3 ml / g to 0.5 ml / g. The gas adsorption sheet for a secondary battery with a cover film according to claim 1.

4. The gas adsorption sheet for a secondary battery with a cover film according to claim 1, wherein the gas adsorption particles have a surface treated surface with silicone.

5. The gas adsorption sheet for a secondary battery with a cover film according to claim 4, wherein the silicone has an ethoxysilane group or a methoxysilane group.

6. The gas adsorption sheet for a secondary battery with a cover film according to claim 4, wherein the silicone is a silane coupling agent containing an epoxy group or an amino group.

7. The gas adsorption sheet for a secondary battery with a cover film according to claim 4, wherein the silicone is an alkoxysilane or an organosilazane compound.

8. The gas adsorption sheet for a secondary battery with a cover film according to claim 1, wherein the binder resin is an acrylic resin.

9. The binder resin contains a structural unit derived from an alkyl (meth)acrylate, and the alkyl (meth)acrylate has a linear or branched alkyl group having 4 to 12 carbon atoms. The gas adsorption sheet for a secondary battery with a cover film according to claim 8.

10. The gas adsorption sheet for a secondary battery with a cover film according to claim 1, wherein the binder resin is butyl rubber, isoprene rubber, polyisobutylene rubber, ethylene propylene rubber, or a silicone resin.

11. The cover film-attached gas adsorption sheet for a secondary battery according to claim 1, wherein the content ratio of the gas adsorption particles is 10 parts by weight to 90 parts by weight with respect to 100 parts by weight of the gas adsorption sheet for a secondary battery.

12. The cover film-attached gas adsorption sheet for a secondary battery according to claim 1, wherein the material constituting the heat-resistant base material is polyamideimide, polyetherimide, polyphenylene sulfide, polyethylene naphthalate, polyimide or polyetheretherketone.

13. The cover film-attached gas adsorption sheet for a secondary battery according to claim 1, wherein the cover film includes a base material and an adhesive layer disposed on at least one side of the base material.

14. The cover film-attached gas adsorption sheet for a secondary battery according to claim 13, wherein the adhesive layer is formed from an adhesive containing a base polymer, and the content ratio of the structural unit derived from the organic acid monomer is preferably 0.5 parts by weight or less with respect to 100 parts by weight of the base polymer.

15. The cover film-attached gas adsorption sheet for a secondary battery according to claim 13, wherein the cover film is peelable.

16. An all-solid-state secondary battery using the gas adsorption sheet according to claim 1 inside a battery case.

17. An all-solid-state secondary battery using a sulfide-based solid electrolyte and using the gas adsorption sheet according to claim 1 inside a battery case.

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