Laminate for electrochemical element and electrochemical element

Abstract

The purpose of the present invention is to provide a laminate for electrochemical elements which can be advantageously used as an element member having excellent blocking properties and low-temperature adhesion. This laminate is provided with a base material and a functional layer. The functional layer contains heat-resistant microparticles, adhesive particles containing an adhesive polymer, and a bonding material. The adhesive polymer contains a polyester polymer having a glass transition temperature in the range of 10-95°C. When viewing the laminate in plan view from the functional layer side, the functional layer has an adhesion region formed from the adhesive particles, and a heat-resistant region formed from the heat-resistant microparticles and the bonding material. Further, the volume average particle diameter of the adhesive particles in the laminate is greater than the lamination-direction average height of the heat-resistant region.

Description

[Technical Field]

[0001] The present invention relates to a laminate for an electrochemical device and an electrochemical device. [Background technology]

[0002] Electrochemical devices such as lithium ion secondary batteries, electric double layer capacitors, and lithium ion capacitors are small, lightweight, have high energy density, and are capable of repeated charging and discharging, and are therefore used in a wide range of applications. Electrochemical devices generally include multiple electrodes and element components such as separators that isolate the electrodes and prevent internal short circuits.

[0003] Here, laminates for electrochemical devices have been used for device components such as electrodes and separators, which are formed by laminating layers (functional layers) for achieving desired functions such as heat resistance and adhesiveness on a substrate. For example, Patent Document 1 discloses a separator formed by laminating a porous layer containing a resin and a filler, having a film thickness of less than 8.0 μm, and having a surface roughness (Ra) of 0.15 μm or less, on a polyolefin porous film substrate. According to Patent Document 1, the porous layer of the separator has excellent ion permeability and peel strength. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-177773 Summary of the Invention [Problem to be solved by the invention]

[0005] Here, element components such as electrodes and separators are sometimes stored and transported in a rolled-up state, and during such storage and transport, the element components may stick together (i.e., block) via the functional layer. In other words, a laminate used as an element component is required to suppress blocking via the functional layer (to improve blocking resistance). On the other hand, the functional layer of the laminate is required to exhibit excellent adhesiveness when manufacturing an electrochemical device. In particular, when a cell is produced by stacking multiple element components such as electrodes and separators, arbitrarily winding them, and then hot-pressing them, shortening the hot-pressing time to improve cell production efficiency, etc., has been problematic in that the functional layer in the laminate located in the center of the cell, where heat is not sufficiently transmitted, is unlikely to exhibit sufficient adhesiveness. In other words, a laminate used as an element component is required to ensure the above-mentioned blocking resistance while also exhibiting excellent adhesiveness at low temperatures (excellent low-temperature adhesiveness).

[0006] However, when used as a component of an element, the above-mentioned conventional laminates are unable to exhibit a good balance between blocking resistance and low-temperature adhesion.

[0007] Therefore, an object of the present invention is to provide a laminate for an electrochemical device that can be advantageously used as a device component having excellent blocking resistance and low-temperature adhesion, and an electrochemical device that includes the laminate for an electrochemical device as a device component. [Means for solving the problem]

[0008] The present inventors have conducted extensive research to achieve the above object, and have found that when preparing a laminate, a functional layer is formed on a substrate using heat-resistant fine particles (fine particles capable of exhibiting heat resistance), adhesive particles (particles capable of exhibiting adhesiveness) containing a polyester polymer having a glass transition temperature within a predetermined range, and a binder, and the functional layer is given predetermined properties, thereby enabling the resulting laminate to be used as a device component having excellent both blocking resistance and low-temperature adhesion, and have completed the present invention.

[0009] The present invention aims to advantageously solve the above-mentioned problems, and provides a laminate for an electrochemical device comprising a substrate and a functional layer disposed on the substrate, wherein the functional layer contains heat-resistant fine particles, adhesive particles containing an adhesive polymer, and a binder, and the adhesive polymer contains a polyester polymer having a glass transition temperature in the range of 10°C to 95°C, and when viewed from above from the functional layer side, the functional layer comprises an adhesive region made of the adhesive particles and a heat-resistant region made of the heat-resistant fine particles and the binder, and the volume average particle diameter of the adhesive particles is larger than the average height in the stacking direction of the heat-resistant region. The above-mentioned laminate can be advantageously used as a device component having excellent blocking resistance and low-temperature adhesion. In the present invention, the "glass transition temperature" can be measured using the method described in the examples. In the present invention, the "volume average particle size" of the adhesive particles can be measured using the method described in the Examples. In the present invention, the "average height in the stacking direction" of the heat-resistant region can be measured using the method described in the Examples.

[0010] In the laminate for an electrochemical device of the present invention, the adhesive particles preferably further contain a meltable additive having a melting point in the range of 40° C. to 95° C. If the adhesive particles contain a meltable additive having a melting point within the above range, the low-temperature adhesiveness of the device member made of the laminate can be further improved. In the present invention, the "melting point" of the meltable additive can be determined by measuring using a differential scanning calorimeter (DSC) under conditions of a temperature increase of 100°C / min and taking the maximum value of the obtained DSC curve.

[0011] In the laminate for an electrochemical device of the present invention, the meltable additive is preferably at least one selected from the group consisting of ester wax, paraffin wax, and a crystalline polyester resin having a glass transition temperature not in the range of 10° C. to 95° C. Use of at least one of the above-mentioned meltable additives can further improve the low-temperature adhesiveness of the device member made of the laminate. In the present invention, the "crystalline polyester resin" does not have a glass transition temperature in the range of 10°C or more and 95°C or less, and is therefore a different component from the "polyester polymer" which has a glass transition temperature within this range.

[0012] In the laminate for an electrochemical device of the present invention, the adhesive particles preferably have a volume average particle diameter of 1.0 μm or more and 10.0 μm or less. If the volume average particle diameter of the adhesive particles is within the above range, the heat resistance of the device member made of the laminate can be increased, and the blocking resistance and low-temperature adhesion can be further improved.

[0013] Furthermore, in the laminate for electrochemical devices of the present invention, the ratio of the volume average particle diameter of the adhesive particles to the average height in the stacking direction of the heat-resistant region is preferably 1.1 to 10.0. If the ratio of the volume average particle diameter of the adhesive particles to the average height in the stacking direction of the heat-resistant region (volume average particle diameter of adhesive particles / average height in the stacking direction of the heat-resistant region) is within the above-mentioned range, it is possible to further improve the blocking resistance and low-temperature adhesion while increasing the heat resistance of the device member made of the laminate.

[0014] In the laminate for electrochemical devices of the present invention, the volume ratio of the content of the heat-resistant fine particles to the content of the adhesive particles in the functional layer is preferably 55 / 45 or more and 95 / 5 or less. If the volume ratio of the content of the heat-resistant fine particles to the content of the adhesive particles in the functional layer (heat-resistant fine particles / adhesive particles) is within the above-mentioned range, the heat resistance of the device member made of the laminate can be increased while the low-temperature adhesion can be further improved.

[0015] In the laminate for electrochemical devices of the present invention, the adhesive particles preferably have an average circularity of 0.90 or more and 0.99 or less. If the average circularity of the adhesive particles is within the above-mentioned range, the low-temperature adhesiveness of the device member made of the laminate can be further improved, and the device characteristics (rate characteristics, cycle characteristics) of an electrochemical device including the device member can be improved. In the present invention, the "average circularity" of the adhesive particles can be measured using the method described in the Examples.

[0016] In the laminate for an electrochemical device of the present invention, the heat-resistant fine particles are preferably inorganic fine particles. If inorganic fine particles are used as the heat-resistant fine particles, the heat resistance of the device member made of the laminate can be improved.

[0017] In the laminate for an electrochemical element of the present invention, the inorganic fine particles preferably include at least one selected from the group consisting of alumina particles, boehmite particles, barium sulfate particles, and magnesium hydroxide particles. Use of at least one of the inorganic fine particles described above can further improve the heat resistance of the element member made of the laminate.

[0018] Furthermore, the present invention aims to advantageously solve the above-mentioned problems, and provides an electrochemical device comprising any one of the above-mentioned laminates for electrochemical devices. An electrochemical device comprising any one of the above-mentioned laminates as a device component has excellent device characteristics such as rate characteristics and cycle characteristics. [Effects of the Invention]

[0019] According to the present invention, it is possible to provide a laminate for an electrochemical device that can be advantageously used as a device component having excellent blocking resistance and low-temperature adhesion, and an electrochemical device including the laminate for an electrochemical device as a device component. [Brief explanation of the drawings]

[0020] [Figure 1]1 is a plan view schematically showing an example of a laminate for an electrochemical device according to the present invention when viewed from the functional layer side. [Figure 2] 1 is a cross-sectional view schematically showing an example of a cross section in the stacking direction of a laminate for an electrochemical device according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, embodiments of the present invention will be described in detail. The laminate for an electrochemical device of the present invention can be used as element members such as separators and electrodes (positive and negative electrodes).The electrochemical device of the present invention includes the laminate for an electrochemical device of the present invention as an element member.

[0022] (Laminate for electrochemical devices) The laminate of the present invention includes a substrate and a functional layer formed on the substrate. When the laminate is viewed from above from the functional layer side, the functional layer on the substrate includes at least an adhesive region made of adhesive particles and a heat-resistant region made of heat-resistant fine particles and a binder. The adhesive particles constituting the adhesive region have a volume-average particle diameter greater than the average height in the stacking direction of the heat-resistant region.

[0023] The laminate of the present invention having such a configuration can adhere well to the substrate via the functional layer, presumably because there are many places in the functional layer where the adhesive particles in the adhesive region protrude beyond the heat-resistant region. In addition, it is believed that the polyester polymer derived from the adhesive particles melted by the heat press penetrates into the matrix of the heat-resistant region formed by binding the heat-resistant fine particles with the binder, thereby acting as an anchor (obtaining an anchor effect), improving the low-temperature adhesion of the device component made of the laminate. On the other hand, it is believed that the heat-resistant region prevents the polyester polymer derived from the adhesive particles melted by the heat press from spreading excessively in a direction parallel to the spreading direction of the substrate surface, thereby ensuring a path for charge carriers such as lithium ions, improving device characteristics such as rate characteristics and cycle characteristics.

[0024] An example of the laminate of the present invention will be further described with reference to FIGS. 1 is a plan view schematically illustrating an example of a laminate 100 for an electrochemical device according to the present invention, as viewed from the functional layer side. In FIG. 1, a heat-resistant region 12 and a plurality of adhesive regions 11 surrounded by the heat-resistant region 12 are present on the surface of a functional layer 10 included in the laminate 100 for an electrochemical device. FIG. 2 is a cross-sectional view schematically illustrating an example of a cross section in the stacking direction of a laminate 100 for electrochemical devices according to the present invention. In FIG. 2, the laminate 100 for electrochemical devices is formed by stacking a functional layer 10 on a substrate 20, and the functional layer 10 has an adhesive region 11 and a heat-resistant region 12. Also, in FIG. 2, the adhesive region 11 is composed of adhesive particles 11a. On the other hand, the heat-resistant region 12 is formed by heat-resistant fine particles 12a bound by a binder 12b, which are stacked in the stacking direction (thickness direction). In FIG. 2, the particle diameter D of the adhesive particles 11a (height from the surface of the substrate 20 in the stacking direction) is larger than the height T of the heat-resistant region 12 in the stacking direction. In the laminate of the present invention, the volume-average particle diameter of the adhesive particles is larger than the average height in the stacking direction of the heat-resistant region, and therefore, it is believed that there are many protruding portions of the adhesive particles, as shown in FIG. 2.

[0025] The laminate of the present invention is not limited to the examples shown in FIGS. 1 and 2. For example, in the laminate of the present invention, functional layers may be provided on both sides of the substrate. When the laminate of the present invention has functional layers on both sides of the substrate, at least one of the functional layers may have predetermined properties. In addition, in the laminate of the present invention, the adhesive region of the functional layer may be composed of a single adhesive particle as shown in FIG. 2, or may be formed by a collection of multiple adhesive particles. Furthermore, in the laminate of the present invention, the adhesive region of the functional layer may be composed only of adhesive particles as shown in FIG. 2, or may be composed of adhesive particles and at least one selected from the group consisting of a binder and other components described below. In addition, in the laminate of the present invention, the heat-resistant region of the functional layer may be composed only of heat-resistant fine particles and a binder as shown in FIG. 2, or may be composed of heat-resistant fine particles, a binder, and other components described below.

[0026] <Volume average particle size of adhesive particles> The volume average particle diameter of the adhesive particles is not particularly limited as long as it is greater than the average height in the stacking direction of the heat-resistant region, but is preferably 1.0 μm or more, more preferably 2.5 μm or more, and even more preferably 5.0 μm or more, and is preferably 10.0 μm or less, more preferably 9.0 μm or less, and even more preferably 8.0 μm or less. If the volume average particle diameter of the adhesive particles is 1.0 μm or more, it is presumed that the adhesive particles in the adhesive region protrude further than the heat-resistant region, which further improves the low-temperature adhesiveness of the element member made of the laminate. Furthermore, it is presumed that the larger volume average particle diameter of the adhesive particles allows the heat-resistant fine particles to be more densely concentrated in the heat-resistant region adjacent to the adhesive region, which further improves the heat resistance of the element member made of the laminate. In addition, it is presumed that the blocking resistance of the element member made of the laminate can be further improved. On the other hand, if the volume average particle diameter of the adhesive particles is 10.0 μm or less, the number of adhesive particles per unit volume of the functional layer (particle count) increases, which is presumably because the number of adhesion points increases when adhering an element member having the functional layer to an adherend, and the low-temperature adhesion of the element member can be further improved. In addition, the adhesive particles can be prevented from falling off, and a functional layer can be formed on the substrate in which adhesion areas made of adhesive particles are evenly distributed. The volume average particle size of the adhesive particles can be adjusted, for example, by changing the manufacturing conditions for the adhesive particles.

[0027] <Average height of heat-resistant area in the stacking direction> The average height of the heat-resistant region in the stacking direction is not particularly limited as long as it is smaller than the volume average particle diameter of the adhesive particles, but is preferably 0.5 μm or more, more preferably 0.8 μm or more, even more preferably 1.0 μm or more, and preferably less than 6.0 μm, preferably less than 5.0 μm, more preferably less than 4.0 μm, and even more preferably less than 2.5 μm. If the average height of the heat-resistant region in the stacking direction is 0.5 μm or more, the heat resistance of the element member including the functional layer can be sufficiently ensured, and if it is less than 6.0 μm, the ion diffusibility of the functional layer can be ensured, thereby improving the rate characteristics and cycle characteristics of the electrochemical element. The average height of the heat-resistant region in the stacking direction can be adjusted, for example, by changing the conditions for forming the functional layer (the content of heat-resistant microparticles and / or binder in the functional layer composition used to form the functional layer, and the thickness of the coating obtained by supplying the functional layer composition onto the substrate).

[0028] <Volume average particle size of adhesive particles / Average height in the layering direction of the heat-resistant region> The ratio of the volume average particle diameter of the adhesive particles to the average height of the heat-resistant region in the stacking direction (volume average particle diameter of adhesive particles / average height of the heat-resistant region in the stacking direction) is preferably 1.1 or more, more preferably 1.2 or more, even more preferably 1.6 or more, and preferably 10.0 or less, more preferably 5.0 or less, and even more preferably 3.5 or less. If the ratio is 1.1 or more, it is presumed that this is because the adhesive particles in the adhesive region sufficiently protrude beyond the heat-resistant region, which further improves the low-temperature adhesiveness of the element member made of the laminate. On the other hand, if the ratio is 10.0 or less, it is presumed that this is because the number of adhesive particles (particle number) per unit volume of the functional layer increases, thereby increasing the number of adhesive points when adhering the element member having the functional layer to the adherend, which further improves the low-temperature adhesiveness of the element member made of the laminate.

[0029] <Functional layer> The functional layer of the laminate of the present invention having the above-described structure contains heat-resistant particles, adhesive particles, and a binder. The functional layer may contain components (other components) other than the heat-resistant particles, adhesive particles, and binder.

[0030] <<Heat-resistant fine particles>> Here, the heat-resistant fine particles contained in the functional layer are not particularly limited, and examples thereof include fine particles made of inorganic materials (i.e., inorganic fine particles) and fine particles made of organic materials (i.e., organic fine particles) that are stable and electrochemically stable in the environment in which the electrochemical element is used. As the heat-resistant fine particles, inorganic fine particles and organic fine particles may be used alone, or inorganic fine particles and organic fine particles may be used in combination.

[0031] [Inorganic fine particles] Examples of inorganic fine particles include inorganic oxide particles such as aluminum oxide (alumina, Al2O3), aluminum oxide hydrate (boehmite, AlOOH), gibbsite (Al(OH)3), silicon oxide, magnesium oxide (magnesia), magnesium hydroxide, calcium oxide, titanium oxide (titania), barium titanate (BaTiO3), ZrO, and alumina-silica composite oxide; nitride particles such as aluminum nitride and boron nitride; covalently bonded crystalline particles such as silicon and diamond; sparingly soluble ionic crystalline particles such as barium sulfate, calcium fluoride, and barium fluoride; and clay fine particles such as talc and montmorillonite. These particles may be subjected to element substitution, surface treatment, solid solution formation, etc., as necessary. The inorganic fine particles may be used singly or in combination of two or more.

[0032] [Organic fine particles] Unlike adhesive particles and binders containing adhesive polymers such as polyester polymers, organic fine particles are fine particles made of polymers that do not have adhesive properties. Examples of organic fine particles include various crosslinked polymer particles such as crosslinked polymethyl methacrylate, crosslinked polystyrene, crosslinked polydivinylbenzene, styrene-divinylbenzene copolymer crosslinked products, polystyrene, polyimide, polyamide, polyamideimide, melamine resin, phenolic resin, and benzoguanamine-formaldehyde condensate, as well as heat-resistant polymer particles such as polysulfone, polyacrylonitrile, polyaramid, polyacetal, and thermoplastic polyimide, as well as modified products and derivatives thereof. The organic fine particles may be used singly or in combination of two or more. As described above, the organic fine particles are made of a polymer that does not have adhesive properties. Specifically, the glass transition temperature of the polymer that makes up the organic fine particles is preferably 150° C. or higher.

[0033] Among the above-mentioned heat-resistant fine particles, from the viewpoint of further improving the heat resistance of the element member consisting of the laminate, inorganic fine particles and organic fine particles composed of a polymer having a glass transition temperature of 150°C or higher are preferred, inorganic fine particles are more preferred, and particles composed of alumina (alumina particles), particles composed of boehmite (boehmite particles), particles composed of barium sulfate (barium sulfate particles), and particles composed of magnesium hydroxide (magnesium hydroxide particles) are even more preferred.

[0034] [Properties of heat-resistant particles] The heat-resistant fine particles preferably have a volume-average particle diameter of 0.1 μm or more, more preferably 0.2 μm or more, even more preferably 0.3 μm or more, and preferably 1.0 μm or less, more preferably 0.9 μm or less, and even more preferably 0.8 μm or less. When the heat-resistant fine particles have a volume-average particle diameter of 0.1 μm or more, a decrease in the ionic conductivity of the functional layer due to excessively dense packing of the heat-resistant fine particles in the functional layer can be suppressed, allowing the electrochemical device to exhibit excellent device characteristics (especially rate characteristics). On the other hand, when the heat-resistant fine particles have a volume-average particle diameter of 1.0 μm or less, even when the functional layer is thinned, the device component comprising the laminate including the functional layer can fully exhibit excellent heat resistance. Therefore, the capacity of the electrochemical device can be increased while ensuring sufficient heat resistance of the device component.

[0035] <<Adhesive particles>> The adhesive particles are particles containing an adhesive polymer including at least a polyester polymer, and the particles may contain components (optional components) other than the adhesive polymer. That is, the adhesive particles may be particles consisting essentially of the adhesive polymer alone, or may be particles consisting of the adhesive polymer and the optional component.

[0036] [Adhesive polymer] The adhesive polymer contains at least a polyester polymer as described above, and optionally contains an adhesive polymer other than a polyester polymer (another adhesive polymer).

[0037] [Polyester polymer] A polyester polymer is a polymer obtained by condensation polymerization of an alcohol component and a carboxylic acid component. In other words, a polyester polymer is a condensation polymer having repeating units derived from an alcohol component (alcohol units) and repeating units derived from a carboxylic acid component (carboxylic acid units).

[0038] -Alcohol content- The alcohol component can be a polyhydric alcohol, including dihydric alcohols and trihydric or higher alcohols.

[0039] Examples of dihydric alcohols include chain aliphatic diols, diols having an oxyalkylene group, and diols having a carbon ring. Examples of the chain aliphatic diol include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, and 1,12-dodecanediol. Examples of the diol having an oxyalkylene group include diethylene glycol, triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. Examples of diols having a carbon ring include 1,4-cyclohexanedimethanol, bisphenols (e.g., bisphenol A, bisphenol F, bisphenol S), hydrogenated bisphenols, and alkylene oxide adducts of bisphenols (e.g., ethylene oxide adducts, propylene oxide adducts, butylene oxide adducts).

[0040] Examples of trihydric or higher alcohols include glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol, and dipentaerythritol.

[0041] The alcohol component may be used alone or in combination of two or more. The alcohol component is preferably a diol having a carbon ring, more preferably a bisphenol, a hydrogenated bisphenol, or an alkylene oxide adduct of a bisphenol, still more preferably an alkylene oxide adduct of a bisphenol, particularly preferably an alkylene oxide adduct of bisphenol A, and most preferably an ethylene oxide adduct of bisphenol A or a propylene oxide adduct of bisphenol A.

[0042] -Carboxylic acid component- As the carboxylic acid component, polycarboxylic acids and their anhydrides, as well as their halides, can be used. Examples of polycarboxylic acids include chain aliphatic polycarboxylic acids such as oxalic acid, malonic acid, succinic acid, adipic acid, sebacic acid, dodecanedioic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, and glutaconic acid; and aromatic polycarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, naphthalenedicarboxylic acid, and pyromellitic acid.

[0043] The carboxylic acid component may be used alone or in combination of two or more thereof. Preferred carboxylic acid components are terephthalic acid, isophthalic acid, fumaric acid, trimellitic acid, and anhydrides thereof.

[0044] -Condensation polymerization- The method for condensation polymerizing the alcohol component and the carboxylic acid component is not particularly limited, and known polymerization aids and polymerization conditions can be used.

[0045] - Glass transition temperature - Here, the polyester polymer must have a glass transition temperature of 10°C or higher and 95°C or lower, preferably 15°C or higher, more preferably 30°C or higher, even more preferably 40°C or higher, particularly preferably 56°C or higher, and preferably 90°C or lower, more preferably 80°C or lower. If the glass transition temperature of the polyester polymer is lower than 10°C, the blocking resistance of the element member made of the laminate will decrease. On the other hand, if the glass transition temperature of the polyester polymer is higher than 95°C, the low-temperature adhesion of the element member made of the laminate will decrease. The glass transition temperature of the polyester polymer can be controlled by changing the type of alcohol component and / or carboxylic acid component used in preparing the polyester polymer, or by changing the polymerization conditions.

[0046] The melting point of the polyester polymer may be observed by the above-mentioned method applied to "meltable additives" such as "crystalline polyester resins" described below (i.e., the polyester polymer may be crystalline). However, even if the polyester polymer has a melting point, it is preferable that the melting point is outside the range of 40°C or higher and 95°C or lower. In other words, it is preferable that the polyester polymer does not have a melting point in the range of 40°C or higher and 95°C or lower.

[0047] [Other adhesive polymers] The adhesive polymer other than the polyester polymer optionally contained in the adhesive particles is preferably a polymer containing at least an aromatic monovinyl monomer unit (aromatic vinyl polymer). The aromatic vinyl polymer may contain a monomer unit other than the aromatic monovinyl monomer unit (other monomer unit).

[0048] - Aromatic monovinyl monomer unit - When the adhesive polymer contains a polymer containing an aromatic monovinyl monomer unit, the elasticity of the adhesive particles is improved, and the strength of the functional layer can be increased. Here, examples of aromatic monovinyl monomers that can form aromatic monovinyl monomer units are not particularly limited, and include, for example, styrene, α-methylstyrene, styrenesulfonic acid, butoxystyrene, vinylnaphthalene, etc. These may be used alone or in combination of two or more. Among these, styrene is preferred.

[0049] The content of the aromatic monovinyl monomer unit in the aromatic vinyl polymer is preferably 30% by mass or more, more preferably 60% by mass or more, and preferably 90% by mass or less, more preferably 85% by mass or less, when the total amount of all monomer units in the aromatic vinyl polymer is taken as 100% by mass. When the content of the aromatic monovinyl monomer unit is 30% by mass or more, the elasticity of the adhesive particles can be sufficiently improved, thereby increasing the strength of the functional layer. Therefore, the low-temperature adhesiveness of the device member comprising the laminate can be sufficiently improved. On the other hand, when the content of the aromatic monovinyl monomer unit is 90% by mass or less, the flexibility of the adhesive particles can be increased, thereby sufficiently improving the low-temperature adhesiveness of the device member comprising the laminate. Furthermore, if the content of the aromatic monovinyl monomer unit is within the above-mentioned range, it is presumed that a good balance between the elasticity and flexibility of the adhesive particles can be ensured, as described above. This sufficiently improves the low-temperature adhesiveness of the device member comprising the laminate, while allowing the electrochemical device to exhibit excellent device characteristics (rate characteristics, cycle characteristics) using the device member. In the present invention, the "content ratio of each monomer unit" contained in the polymer is 1 It can be measured using nuclear magnetic resonance (NMR) techniques such as H-NMR.

[0050] -Other monomer units- The other monomer units are not particularly limited, but preferred examples include crosslinkable monomer units and (meth)acrylic acid ester monomer units. In the present invention, "(meth)acrylic" means acrylic and / or methacrylic.

[0051] The crosslinkable monomer capable of forming the crosslinkable monomer unit is a monomer capable of forming a crosslinked structure during or after polymerization by heating or irradiation with energy rays. When the aromatic vinyl polymer contains the crosslinkable monomer unit, the elasticity of the adhesive particles can be improved, and as a result, the low-temperature adhesiveness of the element member made of the laminate can be sufficiently improved.

[0052] Examples of monomers capable of forming crosslinkable monomer units include polyfunctional monomers having two or more polymerization reactive groups. Examples of such polyfunctional monomers include divinyl compounds such as allyl methacrylate and divinylbenzene; di(meth)acrylic acid ester compounds such as diethylene glycol dimethacrylate, ethylene glycol dimethacrylate, diethylene glycol diacrylate, and 1,3-butylene glycol diacrylate; tri(meth)acrylic acid ester compounds such as trimethylolpropane trimethacrylate and trimethylolpropane triacrylate; and ethylenically unsaturated monomers containing epoxy groups such as allyl glycidyl ether and glycidyl methacrylate. These may be used alone or in combination of two or more. Among these, divinylbenzene is preferred.

[0053] The content of the crosslinkable monomer units in the aromatic vinyl polymer is preferably 0.01% by mass or more, preferably 2% by mass or less, more preferably 1.5% by mass or less, and even more preferably 1% by mass or less, when the amount of all monomer units in the aromatic vinyl polymer is taken as 100% by mass. When the content of the crosslinkable monomer units is within the above range, the aromatic vinyl polymer contained in the adhesive particles can be sufficiently prevented from leaching into the electrolyte solution. Furthermore, the elasticity of the adhesive particles can be improved, and as a result, the low-temperature adhesiveness of the element member made of the laminate can be sufficiently improved.

[0054] In addition, examples of (meth)acrylic acid ester monomers that can form (meth)acrylic acid ester monomer units include acrylates such as methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, butyl acrylate (n-butyl acrylate, t-butyl acrylate, etc.), pentyl acrylate, hexyl acrylate, heptyl acrylate, octyl acrylate (2-ethylhexyl acrylate, etc.), nonyl acrylate, decyl acrylate, lauryl acrylate, n-tetradecyl acrylate, and stearyl acrylate. and alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, butyl methacrylate (such as n-butyl methacrylate and t-butyl methacrylate), pentyl methacrylate, hexyl methacrylate, heptyl methacrylate, octyl methacrylate (such as 2-ethylhexyl methacrylate), nonyl methacrylate, decyl methacrylate, lauryl methacrylate, n-tetradecyl methacrylate, and stearyl methacrylate. These (meth)acrylic acid ester monomers may be used alone or in combination of two or more. Among these, n-butyl acrylate, 2-ethylhexyl acrylate, and methyl methacrylate are preferred, and n-butyl acrylate and 2-ethylhexyl acrylate are more preferred.

[0055] The content of (meth)acrylic acid ester monomer units in the aromatic vinyl polymer is preferably 5% by mass or more, more preferably 10% by mass or more, and preferably 65% ​​by mass or less, more preferably 60% by mass or less, and even more preferably 35% by mass or less, when the total amount of monomer units in the aromatic vinyl polymer is taken as 100% by mass. If the content of (meth)acrylic acid ester monomer units is 5% by mass or more, an excessive decrease in the glass transition temperature of the aromatic vinyl polymer can be prevented, and the blocking resistance of the element member made of the laminate can be sufficiently improved. On the other hand, if the content of (meth)acrylic acid ester monomer units is 65% by mass or less, the low-temperature adhesion of the element member made of the laminate can be sufficiently improved.

[0056] In addition to the above-mentioned crosslinkable monomer unit and (meth)acrylic acid ester monomer unit, other monomer units are not particularly limited and include monomer units described later in the section "Binder" (excluding those corresponding to any of aromatic monovinyl monomer units, crosslinkable monomer units, and (meth)acrylic acid ester monomer units). Furthermore, the content of monomer units other than the above-mentioned aromatic monovinyl monomer units, crosslinkable monomer units, and (meth)acrylic acid ester monomer units in the aromatic vinyl polymer is preferably 0% by mass or more and 10% by mass or less, more preferably 0% by mass or more and 7% by mass or less, and even more preferably 0% by mass or more and 5% by mass or less, when the total monomer units in the aromatic vinyl polymer is taken as 100% by mass, from the viewpoint of ensuring the stability of the functional layer composition used to form the functional layer.

[0057] - Glass transition temperature - Here, the glass transition temperature of the other adhesive polymers such as the aromatic vinyl polymers described above is preferably 10° C. or higher, more preferably 30° C. or higher, even more preferably 40° C. or higher, and is preferably 90° C. or lower, more preferably 80° C. or lower. If the glass transition temperature in the adhesive particles is 10° C. or higher, the blocking resistance of the element member made of the laminate can be further improved, and if it is 90° C. or lower, the low-temperature adhesiveness of the element member can be further improved. The glass transition temperature of other adhesive polymers can be controlled by changing the type and / or ratio of the monomers used in preparing the polymer, or the polymerization conditions.

[0058] Here, when the adhesive polymer contained in the adhesive particles is composed of a polyester polymer and another adhesive polymer, it is preferable that these two or more (plural) polymers form particles with a heterogeneous phase structure formed by physical or chemical bonding of two or more different polymers. Specific examples of heterogeneous phase structures include a core-shell structure in which the central part (core) and the outer shell part (shell) are formed of different polymers in spherical particles; and a side-by-side structure in which two or more polymers are juxtaposed. In the present invention, the "core-shell structure" includes not only a structure in which the shell part completely covers the outer surface of the core part, but also a structure in which the shell part partially covers the outer surface of the core part. When the adhesive polymer is composed of a polyester polymer and another adhesive polymer, it is preferable that the core portion is composed of the other adhesive polymer (for example, the aromatic vinyl polymer described above) and the shell portion is composed of the polyester polymer.

[0059] [Optional ingredients] A preferred example of an optional component other than the adhesive polymer is a meltable additive having a melting point in the range of 40° C. to 95° C. When the adhesive particles contain a meltable additive, the low-temperature adhesiveness of the element member made of the laminate can be further improved.

[0060] Here, as described above, the melting point of the meltable additive must be 40° C. or higher and 95° C. or lower, preferably 42° C. or higher, more preferably 45° C. or higher, even more preferably 50° C. or higher, preferably 90° C. or lower, more preferably 70° C. or lower, and even more preferably 60° C. or lower. If the melting point of the meltable additive is 40° C. or higher, the blocking resistance of the element member made of the laminate will not be excessively impaired, and if the melting point of the meltable additive is 95° C. or lower, the low-temperature adhesion of the element member made of the laminate can be sufficiently improved.

[0061] Examples of meltable additives having the above-mentioned melting points include waxes (plant waxes, animal waxes, petroleum waxes, synthetic waxes, and modified products thereof) and crystalline polyester resins. The meltable additives may be used alone or in combination of two or more.

[0062] -wax- Examples of vegetable waxes include candelilla wax, carnauba wax, rice wax, Japan wax, and jojoba oil. An example of an animal wax is beeswax. Examples of petroleum waxes include paraffin wax, microcrystalline wax, and petrolatum wax.

[0063] Synthetic waxes can be classified into Fischer-Tropsch waxes, polyolefin waxes, ester waxes, and the like. Examples of polyolefin waxes include polyethylene wax, polypropylene wax, and polybutylene wax. As the ester wax, both monohydric alcohol fatty acid esters and polyhydric alcohol fatty acid esters can be used. Specific examples of monohydric alcohol fatty acid esters include behenyl stearate. Specific examples of polyhydric alcohol fatty acid esters include pentaerythritol esters such as pentaerythritol tetramyristate, pentaerythritol tetrapalmitate, pentaerythritol tetrastearate, pentaerythritol tetralaurate, and pentaerythritol tetrabehenate; and dipentaerythritol esters such as dipentaerythritol hexamyristate, dipentaerythritol hexapalmitate, and dipentaerythritol hexalaurate.

[0064] -Crystalline polyester resin- The crystalline polyester resin is not particularly limited as long as it has a melting point in the range of 40°C or higher and 95°C or lower and does not have a glass transition temperature in the range of 10°C or higher and 95°C or lower (in other words, it does not have a glass transition temperature itself, or has a glass transition temperature in the range below 10°C and / or above 95°C), and a polymer obtained by condensation polymerization of an alcohol component and a carboxylic acid component can be used. The alcohol component and carboxylic acid component used in preparing the crystalline polyester resin can be any of those described above in the "Polyester Polymer" section. The alcohol component is preferably a chain aliphatic diol, more preferably 1,6-hexanediol. The carboxylic acid component is preferably a chain aliphatic polycarboxylic acid, more preferably sebacic acid. The method for condensation polymerization of the alcohol component and the carboxylic acid component is not particularly limited, and known polymerization aids and polymerization conditions can be used.

[0065] Among the above-mentioned melt-soluble additives, from the viewpoint of further improving the low-temperature adhesion of the element member consisting of the laminate, ester wax, paraffin wax, and crystalline polyester resin are preferred, ester wax and crystalline polyester resin are more preferred, and ester wax is even more preferred.

[0066] - Content of melting additives - Here, the content of the meltable additive in the adhesive particles is preferably 1 part by mass or more, more preferably 2 parts by mass or more, even more preferably 5 parts by mass or more, even more preferably 6 parts by mass or more, particularly preferably 10 parts by mass or more, and preferably 30 parts by mass or less, more preferably 25 parts by mass or less, even more preferably 20 parts by mass or less, and particularly preferably 15 parts by mass or less, per 100 parts by mass of the adhesive polymer. If the content of the meltable additive in the adhesive particles is 1 part by mass or more per 100 parts by mass of the adhesive polymer, the low-temperature adhesiveness of the element member composed of the laminate can be further improved. On the other hand, if the content of the meltable additive in the adhesive particles is 30 parts by mass or less per 100 parts by mass of the adhesive polymer, bleeding out of the meltable additive can be sufficiently suppressed, the blocking resistance of the element member composed of the laminate can be further improved, and the rate characteristics and cycle characteristics of an electrochemical element including the element member can be improved.

[0067] Furthermore, the content of the meltable additive in the functional layer is preferably 1 part by mass or more, more preferably 2 parts by mass or more, even more preferably 5 parts by mass or more, even more preferably 6 parts by mass or more, particularly preferably 10 parts by mass or more, and preferably 30 parts by mass or less, more preferably 25 parts by mass or less, even more preferably 20 parts by mass or less, and particularly preferably 15 parts by mass or less, per 100 parts by mass of the adhesive polymer. If the content of the meltable additive in the functional layer is 1 part by mass or more per 100 parts by mass of the adhesive polymer, the low-temperature adhesiveness of the element member composed of the laminate can be further improved. On the other hand, if the content of the functional layer in the adhesive particle is 30 parts by mass or less per 100 parts by mass of the adhesive polymer, bleeding out of the meltable additive can be sufficiently suppressed, the blocking resistance of the element member composed of the laminate can be further improved, and the rate characteristics and cycle characteristics of the electrochemical element including the element member can be improved.

[0068] [Average circularity] Here, the adhesive particles preferably have an average circularity of 0.90 or more, more preferably 0.92 or more, even more preferably 0.95 or more, particularly preferably 0.97 or more, and particularly preferably 0.99 or less. If the average circularity of the adhesive particles is 0.90 or more, the low-temperature adhesiveness of the element member made of the laminate can be further improved. In addition, the element member made of the laminate can exhibit good adhesiveness even in an electrolyte. On the other hand, if the average circularity of the adhesive particles is 0.99 or less, the resistance of the element member made of the laminate in an electrolyte can be reduced, and the rate characteristics and cycle characteristics of an electrochemical element including the element member can be improved. The average circularity of the adhesive particles can be adjusted by changing the method for preparing the adhesive particles.

[0069] [Preparation of adhesive particles] The method for preparing adhesive particles containing an adhesive polymer is not particularly limited as long as it can granulate an adhesive polymer containing a polyester polymer and optional components such as a meltable additive used as needed (these are collectively referred to as "adhesive particle material"). For example, the following methods 1) to 4): 1) A method in which an adhesive particulate material is dissolved and / or dispersed in an organic solvent in which at least a polyester polymer can be dissolved to prepare a liquid composition, the liquid composition is dispersed in an aqueous medium, and then the organic solvent is removed to form particles of the adhesive particulate material (dissolution suspension method); 2) A method of dispersing an adhesive particulate material in an aqueous medium using a surfactant and / or a dispersion stabilizer, and aggregating the dispersed fine particles to form particles of the adhesive particulate material (emulsion aggregation method); 3) A method in which the adhesive particulate material is melted and kneaded, cooled, and then the resulting kneaded product is pulverized to form particles of the adhesive particulate material (pulverization method); 4) A method of granulating an adhesive particle material by suspension polymerization of a monomer used for preparing other adhesive polymers in the presence of a polyester polymer and optional components used as needed (suspension polymerization method); Examples include:

[0070] Among the above-mentioned particle forming methods, from the viewpoint of easily adjusting the volume average particle size and average circularity of the adhesive particles, the dissolution suspension method, the emulsion aggregation method, and the suspension polymerization method are preferred, and the dissolution suspension method and the suspension polymerization method are more preferred. The dissolution suspension method, emulsion aggregation method, pulverization method, and suspension polymerization method can be carried out by employing known methods and conditions, respectively.

[0071] [Ratio of heat-resistant particles to adhesive particles] Here, the content ratio of heat-resistant fine particles to adhesive particles in the functional layer is not particularly limited, but the volume ratio of the heat-resistant fine particles to the adhesive particle content (heat-resistant fine particles / adhesive particles) is preferably 55 / 45 or more, more preferably 60 / 40 or more, preferably 95 / 5 or less, more preferably 80 / 20 or less, and even more preferably 75 / 25 or less. If the heat-resistant fine particles / adhesive particles (volume basis) value is 55 / 45 or more, the heat resistance of the element member consisting of the laminate can be improved, and if it is 95 / 5 or less, the low-temperature adhesion of the element member can be further improved.

[0072] Furthermore, the mass ratio of the heat-resistant microparticles to the adhesive particle content (heat-resistant microparticles / adhesive particles) is preferably 49 / 51 or more, more preferably 58 / 42 or more, even more preferably 64 / 36 or more, and preferably 99 / 1 or less, more preferably 94 / 6 or less, and even more preferably 91 / 9 or less. If the heat-resistant microparticles / adhesive particles (by mass) ratio is 49 / 51 or more, the heat resistance of the element member made of a laminate having a functional layer can be improved, and if it is 99 / 1 or less, the low-temperature adhesion of the element member can be further improved.

[0073] <<Binding material>> As described above, the binder binds the heat-resistant fine particles together in the heat-resistant region. Examples of the binder include known polymers used as binders, such as conjugated diene polymers, acrylic polymers, polyvinylidene fluoride (PVDF), and polyvinyl alcohol (PVOH). One binder may be used alone, or two or more binders may be used in combination. Preferred binders are water-insoluble polymers that can be dispersed in a dispersion medium such as water, such as conjugated diene polymers, acrylic polymers, and polyvinylidene fluoride (PVDF), with conjugated diene polymers and acrylic polymers being more preferred, and acrylic polymers being even more preferred. In the present invention, a polymer being "water-insoluble" means that when 0.5 g of the polymer is dissolved in 100 g of water at 25°C, the insoluble content is 90 mass % or more.

[0074] [Conjugated diene polymer] The conjugated diene polymer refers to a polymer containing conjugated diene monomer units derived from a conjugated diene monomer. Specific examples of the conjugated diene polymer include, but are not limited to, copolymers containing aromatic monovinyl monomer units and aliphatic conjugated diene monomer units, such as styrene-butadiene copolymer (SBR), butadiene rubber (BR), nitrile rubber (NBR) (copolymers containing acrylonitrile units and 1,3-butadiene units), and hydrogenated products thereof.

[0075] [Acrylic polymer] The acrylic polymer refers to a polymer containing (meth)acrylic acid ester monomer units. The acrylic polymer preferably contains, in addition to the (meth)acrylic acid ester monomer units, at least one of crosslinkable monomer units and acid group-containing monomer units.

[0076] Examples of (meth)acrylic acid ester monomers that can form (meth)acrylic acid ester monomer units include those mentioned above in the "adhesive particles" section. These may be used alone or in combination of two or more. Among these, n-butyl acrylate is preferred. Furthermore, the content of (meth)acrylic acid ester monomer units in the binder (acrylic polymer) is preferably more than 65% by mass, more preferably 70% by mass or more, even more preferably 80% by mass or more, and particularly preferably 90% by mass or more, when the total amount of all monomer units in the binder is 100% by mass, and is preferably 99% by mass or less, more preferably 98% by mass or less, and even more preferably 95% by mass or less.

[0077] Examples of crosslinkable monomers capable of forming crosslinkable monomer units include those mentioned above in the "adhesive particles" section. These may be used alone or in combination of two or more. Among these, allyl methacrylate and allyl glycidyl ether are preferred. Furthermore, the content of the crosslinkable monomer units in the binder (acrylic polymer) is preferably 0.1% by mass or more, preferably 3.0% by mass or less, and more preferably 2.5% by mass or less, when the total amount of monomer units in the binder is taken as 100% by mass. If the content of the crosslinkable monomer units is 0.1% by mass or more, the rate characteristics and cycle characteristics of the electrochemical device can be improved, and if it is 3.0% by mass or less, the low-temperature adhesion of the device member made of the laminate can be further improved.

[0078] Examples of acid group-containing monomers that can form acid group-containing monomer units include monomers having a carboxylic acid group, monomers having a sulfonic acid group, monomers having a phosphoric acid group, and monomers having a hydroxyl group. Examples of the monomer having a carboxylic acid group include monocarboxylic acids and dicarboxylic acids. Examples of the monocarboxylic acids include acrylic acid, methacrylic acid, and crotonic acid. Examples of the dicarboxylic acids include maleic acid, fumaric acid, and itaconic acid. Examples of the monomer having a sulfonic acid group include vinyl sulfonic acid, methyl vinyl sulfonic acid, (meth)allyl sulfonic acid, (meth)acrylic acid-2-ethyl sulfonate, 2-acrylamido-2-methylpropanesulfonic acid, and 3-allyloxy-2-hydroxypropanesulfonic acid. In the present invention, "(meth)allyl" means allyl and / or methallyl. Furthermore, examples of the monomer having a phosphate group include 2-(meth)acryloyloxyethyl phosphate, methyl-2-(meth)acryloyloxyethyl phosphate, and ethyl-(meth)acryloyloxyethyl phosphate. In the present invention, "(meth)acryloyl" means acryloyl and / or methacryloyl. Examples of the monomer having a hydroxyl group include 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, and 2-hydroxypropyl methacrylate. These acid group-containing monomers may be used alone or in combination of two or more. Among these, monomers having a carboxylic acid group are preferred, and methacrylic acid is more preferred.

[0079] Furthermore, the content of the acid group-containing monomer units in the binder (acrylic polymer) is preferably 0.1% by mass or more, preferably 3.0% by mass or less, and more preferably 2.5% by mass or less, when the total amount of all monomer units in the binder is 100% by mass.

[0080] The acrylic polymer used as the binder may contain monomer units (other monomer units) other than the above-mentioned (meth)acrylic acid ester monomer units, crosslinkable monomer units, and acid group-containing monomer units. Examples of other monomers that can form other monomer units that can be contained in the acrylic polymer include aliphatic conjugated diene monomers such as 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, and 2-chloro-1,3-butadiene; aromatic monovinyl monomers described above in the "adhesive particles" section; nitrile group-containing monomers such as acrylonitrile and methacrylonitrile; olefin monomers such as ethylene and propylene; and halogen atoms such as vinyl chloride and vinylidene chloride. Examples of the other monomer include heterocyclic ring-containing monomers, vinyl ester monomers such as vinyl acetate, vinyl propionate, vinyl butyrate, and vinyl benzoate, vinyl ether monomers such as methyl vinyl ether, ethyl vinyl ether, and butyl vinyl ether, vinyl ketone monomers such as methyl vinyl ketone, ethyl vinyl ketone, butyl vinyl ketone, hexyl vinyl ketone, and isopropenyl vinyl ketone, and heterocyclic ring-containing vinyl compound monomers such as N-vinylpyrrolidone, vinylpyridine, and vinylimidazole. Among these, acrylonitrile is preferred as the other monomer. These other monomers may be used singly or in any combination of two or more at any ratio. The content of the other monomer units in the acrylic polymer may be adjusted as appropriate. Here, the binder may contain aromatic monovinyl monomer units, but the content of aromatic monovinyl monomer units in the binder (particularly the acrylic polymer) is preferably less than 30% by mass, more preferably 20% by mass or less, even more preferably 10% by mass or less, particularly preferably 5% by mass or less, and most preferably 0% by mass (i.e., no aromatic monovinyl monomer units are included), when the total amount of all monomer units in the binder is 100% by mass.

[0081] [Properties of binder] The binder preferably has a glass transition temperature of −100° C. or higher, more preferably −90° C. or higher, even more preferably −80° C. or higher, preferably lower than 30° C., more preferably lower than 20° C., even more preferably lower than 15° C., and particularly preferably lower than 10° C. If the binder has a glass transition temperature of −100° C. or higher, the binding ability and strength of the binder can be increased, and if the glass transition temperature is lower than 30° C., the flexibility of the functional layer containing the binder can be sufficiently ensured.

[0082] [Binder content] The content of the binder in the functional layer is preferably 0.1 parts by mass or more, more preferably 0.2 parts by mass or more, even more preferably 0.5 parts by mass or more, and preferably 20 parts by mass or less, more preferably 15 parts by mass or less, even more preferably 10 parts by mass or less, and particularly preferably 6 parts by mass or less, per 100 parts by mass of the heat-resistant fine particles. If the content of the binder in the functional layer is 0.1 parts by mass or more per 100 parts by mass of the heat-resistant fine particles, the heat-resistant fine particles present in the heat-resistant region can be sufficiently prevented from falling off the functional layer, while the low-temperature adhesion of the element member including the functional layer can be further improved. On the other hand, if the content of the binder in the functional layer is 20 parts by mass or less per 100 parts by mass of the heat-resistant fine particles, the rate characteristics and cycle characteristics of the electrochemical element including the element member made of the laminate can be improved.

[0083] [Method for preparing binder] The binder is not particularly limited, and can be prepared, for example, by polymerizing a monomer composition containing the above-mentioned monomers in an aqueous solvent such as water. Here, the proportion of each monomer in the total monomers in the monomer composition is usually the same as the proportion of each monomer unit in the binder. The polymerization method and polymerization reaction are not particularly limited, and known methods can be used.

[0084] <<Other ingredients>> The functional layer of the laminate of the present invention is not particularly limited, and may contain, as components other than the heat-resistant fine particles, adhesive particles, and binder described above, known components such as dispersants and thickeners that can be used in preparing the functional layer (for example, sodium dodecylbenzenesulfonate, and water-soluble polymers such as polyacrylic acid and its salts, and carboxymethylcellulose and its salts).The other components may be used alone or in combination of two or more. In the present invention, a polymer being "water-soluble" means that when 0.5 g of the polymer is dissolved in 100 g of water at 25°C, the insoluble content is less than 1.0 mass %.

[0085] <Base material> The substrate having the functional layer on at least one surface thereof may be appropriately selected depending on the type of element member in which the laminate of the present invention is used. For example, when the laminate of the present invention is used as a separator, a separator substrate is used as the substrate. For example, when the laminate of the present invention is used as an electrode, an electrode substrate is used as the substrate.

[0086] <<Separator substrate>> The separator substrate is not particularly limited, and examples thereof include known separator substrates such as organic separator substrates, which are porous members made of organic materials, and examples of organic separator substrates include microporous membranes or nonwoven fabrics containing polyolefin resins such as polyethylene, polypropylene, polybutene, and polyvinyl chloride, and aromatic polyamide resins. Among these, a microporous film made of a polyolefin resin is preferred from the viewpoint that the ratio of the electrode active material in the electrochemical device can be increased to increase the capacity per volume. The thickness of the separator substrate can be any thickness, preferably 5 μm or more and 30 μm or less, more preferably 5 μm or more and 20 μm or less, and even more preferably 5 μm or more and 18 μm or less.

[0087] <<Electrode base material>> The electrode substrates (positive electrode substrate and negative electrode substrate) are not particularly limited, but examples thereof include electrode substrates in which an electrode mixture layer is formed on a current collector. Here, the current collector, the electrode active materials (positive electrode active material, negative electrode active material) and binders for the electrode composite layer (binders for the positive electrode composite layer, binders for the negative electrode composite layer) in the electrode composite layer, and the method for forming the electrode composite layer on the current collector may be known, and for example, the method described in JP 2013-145763 A may be used.

[0088] <Method of manufacturing laminate> The method for producing the laminate of the present invention is not particularly limited, and for example, a method of forming a functional layer on a release sheet and transferring the functional layer onto a substrate can be used. However, from the viewpoint of eliminating the need for a transfer operation and improving production efficiency, it is preferable to produce the laminate through a step of supplying a functional layer composition containing at least heat-resistant fine particles, adhesive particles, a binder, and a dispersion medium onto a substrate (supplying step), and a step of drying the functional layer composition supplied onto the substrate (drying step).

[0089] <<Composition for functional layer>> As described above, the composition for the functional layer contains at least heat-resistant particles, adhesive particles, and a binder in a dispersion medium, and optionally contains other components. The dispersion medium is not particularly limited, but water is preferably used. The method for preparing the composition for the functional layer is not particularly limited, and any known mixing or dispersing method can be used. Furthermore, when the laminate of the present invention is produced through the supplying step and the drying step as described above, the functional layer of the laminate is made of a dried product of the functional layer composition. Therefore, the components contained in the functional layer are those contained in the functional layer composition, and the preferred abundance ratios of the components in the functional layer composition are the same as the preferred abundance ratios of the components in the functional layer described above.

[0090] <<Supply process>> In the supplying step, the functional layer composition is supplied onto a substrate to form a coating of the functional layer composition on the substrate. The method for supplying the functional layer composition onto the substrate is not particularly limited, and the functional layer composition may be applied to the surface of the substrate, or the substrate may be immersed in the functional layer composition. Furthermore, it is preferable to apply the functional layer composition to the surface of the substrate, as this makes it easier to control the thickness of the functional layer (particularly the average height in the stacking direction of the heat-resistant region). The method for applying the composition for the functional layer to the surface of the substrate is not particularly limited, and examples thereof include the doctor blade method, reverse roll method, direct roll method, gravure coating method, bar coating method, extrusion method, and brush coating method. In the supplying step, a coating of the composition for a functional layer may be formed on only one surface of the substrate, or a coating of the composition for a functional layer may be formed on both surfaces of the substrate.

[0091] <<Drying process>> In the drying step, the coating of the functional layer composition formed on the substrate in the supplying step is dried to remove the dispersion medium, thereby forming a functional layer. The method for drying the coating of the composition for functional layer is not particularly limited and any known method can be used, such as drying with warm air, hot air, or low-humidity air, vacuum drying, or drying by irradiation with infrared rays or electron beams, etc. The drying conditions are not particularly limited, but the drying temperature is preferably 50 to 150°C, and the drying time is preferably 1 to 30 minutes.

[0092] In addition, when manufacturing the laminate of the present invention, a supplying process and a drying process may be performed on one side of the substrate to form a functional layer, and then a supplying process and a drying process may be performed on the other side of the substrate to form a functional layer.

[0093] (electrochemical element) The electrochemical element of the present invention comprises an electrode and a separator, and is characterized in that at least one of the electrode and the separator comprises the laminate of the present invention described above. Since the electrochemical element of the present invention uses the laminate of the present invention described above as at least one of the electrode and the separator, the electrochemical element of the present invention has excellent element characteristics such as rate characteristics and cycle characteristics.

[0094] The electrochemical device of the present invention is not particularly limited, and may be, for example, a lithium ion secondary battery, an electric double layer capacitor, or a lithium ion capacitor, and is preferably a lithium ion secondary battery.

[0095] Hereinafter, a lithium ion secondary battery will be taken as an example of the electrochemical element of the present invention, and a case where the above-described laminate of the present invention is used as a separator of the lithium ion secondary battery will be described, but the electrochemical element of the present invention is not limited thereto.

[0096] <Positive and negative electrodes> As the positive electrode and negative electrode, electrodes made of the known electrode substrates (positive electrode substrate and negative electrode substrate) described above in the section "Substrate" can be used.

[0097] <Electrolyte> As the electrolyte, an organic electrolyte solution in which a supporting electrolyte is dissolved in an organic solvent is usually used. For example, in lithium ion secondary batteries, a lithium salt is used as the supporting electrolyte. Examples of lithium salts include LiPF6, LiAsF6, LiBF4, LiSbF6, LiAlCl4, LiClO4, CF3SO3Li, CF4F9SO3Li, CF3COOLi, (CF3CO)2NLi, (CF3SO2)2NLi, and (C2F5SO2)NLi. Among these, LiPF6, LiClO4, and CF3SO3Li are preferred because they are easily soluble in solvents and exhibit a high degree of dissociation. One type of electrolyte may be used alone, or two or more types may be used in combination. Generally, the lithium ion conductivity tends to increase as the supporting electrolyte with a higher degree of dissociation is used, so the lithium ion conductivity can be adjusted by the type of supporting electrolyte.

[0098] The organic solvent used in the electrolyte is not particularly limited as long as it can dissolve the supporting electrolyte. For example, in lithium ion secondary batteries, carbonates such as dimethyl carbonate (DMC), ethylene carbonate (EC), diethyl carbonate (DEC), propylene carbonate (PC), butylene carbonate (BC), methyl ethyl carbonate (ethyl methyl carbonate (EMC)), and vinylene carbonate; esters such as γ-butyrolactone and methyl formate; ethers such as 1,2-dimethoxyethane and tetrahydrofuran; sulfur-containing compounds such as sulfolane and dimethyl sulfoxide; and the like are suitably used.

[0099] A mixture of these solvents may also be used. Among them, carbonates are preferred because of their high dielectric constant and wide stable potential range. Generally, the lower the viscosity of the solvent used, the higher the lithium ion conductivity tends to be, so the lithium ion conductivity can be adjusted by the type of solvent. The concentration of the electrolyte in the electrolytic solution can be adjusted as appropriate. Known additives may also be added to the electrolytic solution.

[0100] <Method of manufacturing an electrochemical element> The method for producing the electrochemical element of the present invention is not particularly limited. For example, the lithium ion secondary battery, which is an example of the electrochemical element of the present invention described above, can be produced by stacking a positive electrode and a negative electrode with a separator interposed therebetween, rolling or folding the stack as necessary, placing the stack in a battery container, injecting an electrolyte into the battery container, and sealing the container. At least one of the element components among the positive electrode, negative electrode, and separator is the laminate of the present invention. Furthermore, the battery container may contain an expanded metal, a fuse, an overcurrent prevention element such as a PTC element, a lead plate, or the like, as necessary, to prevent pressure buildup within the battery and overcharging and discharging. The shape of the battery may be any shape, such as a coin type, button type, sheet type, cylindrical type, rectangular type, or flat type. [Example]

[0101] The present invention will be specifically described below based on examples, but the present invention is not limited to these examples. In the following description, "%" and "parts" representing amounts are based on mass unless otherwise specified. Furthermore, in a polymer produced by copolymerizing multiple types of monomers, the proportion of a repeating unit (monomer unit) formed by polymerizing a certain monomer in the polymer usually coincides with the ratio (feed ratio) of that certain monomer to all the monomers used in the polymerization of the polymer, unless otherwise specified.

[0102] In the examples and comparative examples, the glass transition temperature, volume average particle diameter, average circularity, average height of the heat-resistant region in the stacking direction, ratio of the volume average particle diameter of the adhesive particles to the average height of the heat-resistant region in the stacking direction, ratio of the content of heat-resistant fine particles to the content of adhesive particles (volume ratio, mass ratio), low-temperature adhesion, blocking resistance, and heat resistance of the separator having a functional layer, and rate characteristics and cycle characteristics of the lithium-ion secondary battery were evaluated by the following methods.

[0103] <Glass transition temperature (Tg) of polyester polymer and binder> The polyester polymer and binder were used as measurement samples. 10 mg of the sample was weighed into an aluminum pan and measured using a differential scanning calorimetry (DSC) analyzer (SII NanoTechnology, Inc., "EXSTAR DSC6220") under the conditions specified in JIS Z 8703. The measurement temperature range was -100°C to 200°C, with a heating rate of 10°C / min. The DSC curve was obtained under the conditions specified in JIS Z 8703. The glass transition temperature (°C) was determined by the intersection of the baseline just before the endothermic peak, where the differential signal (DDSC) was 0.05 mW / min / mg or greater, and the tangent to the DSC curve at the first inflection point after the endothermic peak. <Volume average particle size of binder> The volume-average particle size of the binder was measured by laser diffraction. Specifically, an aqueous dispersion containing the binder (adjusted to a solids concentration of 0.1% by mass) was used as a sample. The particle size distribution (volume basis) was measured using a laser diffraction particle size distribution analyzer (Beckman Coulter, Inc., "LS-230"), and the particle size D50 at which the cumulative volume calculated from the smallest diameter side reached 50% was defined as the volume-average particle size. <Volume average particle size of heat-resistant fine particles> In the particle size distribution (volume basis) measured by laser diffraction, the particle size (D50) at which the cumulative volume calculated from the smallest diameter side becomes 50% was defined as the volume average particle size of the heat-resistant fine particles. <Volume average particle size of adhesive particles> An amount equivalent to 0.1 g of adhesive particles was weighed and placed in a beaker. 0.1 mL of an alkylbenzene sulfonic acid aqueous solution (Fujifilm Drywell) was added as a dispersant. 10-30 mL of diluent (Beckman Coulter Isoton II) was then added to the beaker, and the particles were dispersed in a 20 W ultrasonic disperser for 3 minutes. The volume-average particle size of the adhesive particles was then measured using a particle size analyzer (Beckman Coulter Multisizer) under the following conditions: aperture diameter: 20 μm, medium: Isoton II, and particle count: 100,000. <Average circularity of adhesive particles> A container was pre-filled with 10 mL of ion-exchanged water, to which 0.02 g of a surfactant (alkylbenzene sulfonic acid) was added as a dispersant. 0.02 g of adhesive particles was then added, and the mixture was dispersed using an ultrasonic disperser at 60 W (Watt) for 3 minutes. The adhesive particle concentration at the time of measurement was adjusted to 3,000 to 10,000 particles / μL, and 1,000 adhesive particles with a circle-equivalent diameter of 0.4 μm or more were measured using a flow particle image analyzer (Cimex Corporation, "FPIA-3000"). The circularity is expressed by the following formula (I), and the average circularity is the arithmetic mean of the circularities of the 1,000 adhesive particles measured. Circularity = perimeter of a circle equal to the projected area of ​​the adhesive particle / perimeter of the projected image of the adhesive particle (I) <Average height of heat-resistant area in the stacking direction> The cross section of the separator with the functional layer was observed using the above-mentioned field emission scanning electron microscope (FE-SEM), and the height in the stacking direction of any five points in the heat-resistant region was measured from the obtained SEM image.The average of these measured values ​​was then calculated as the average height in the stacking direction of the heat-resistant region. <Ratio of volume average particle diameter of adhesive particles to average height in stacking direction of heat-resistant region> From the values ​​obtained as described above, the volume average particle diameter / average height in the stacking direction was calculated. <Ratio of heat-resistant fine particle content to adhesive particle content> The ratio (volume ratio, mass ratio) of the content of heat-resistant fine particles to the content of adhesive particles was calculated from the amounts of heat-resistant fine particles and adhesive particles charged when the composition for the functional layer was prepared. The density of alumina particles as heat-resistant fine particles was 4 g / cm. 3 It was calculated as: <Low temperature adhesion> The prepared positive electrode, negative electrode, and separator (having functional layers on both sides with an average height in the stacking direction of the heat-resistant region of 2.0 μm) were each cut into a width of 10 mm and a length of 50 mm. The positive electrode and separator were stacked and pressed using a roll press under conditions of a temperature of 50°C, a load of 8 kN / m, and a press speed of 30 m / min, to obtain an integrated product in which the positive electrode and separator were integrated. The resulting integrated product was placed with the current collector side of the positive electrode facing downwards, and cellophane tape was attached to the surface of the positive electrode. The cellophane tape used was that specified in JIS Z1522. The cellophane tape was fixed to a horizontal test table. One end of the separator was then pulled vertically upward at a pulling rate of 50 mm / min, and the stress when peeled off was measured. The negative electrodes prepared in the examples and comparative examples were also subjected to the same operations as in the case of using the positive electrodes, and the stress was measured. The above-mentioned stress measurement was performed three times for each of the integrated positive electrode and separator and the integrated negative electrode and separator, for a total of six times, and the average stress value was calculated, and the obtained average value was used as the peel strength (N / m). The calculated peel strength was then used to evaluate the low-temperature adhesiveness of the separator with the functional layer according to the following criteria: A higher peel strength indicates that the separator as an element component can exhibit excellent low-temperature adhesiveness due to the functional layer. A: Peel strength 3N / m or more B: Peel strength 2N / m or more and less than 3N / m C: Peel strength 1N / m or more but less than 2N / m D: Peel strength less than 1N / m <Blocking resistance> The prepared separator (featuring functional layers on both sides with an average height in the stacking direction of the heat-resistant region of 2.0 μm) was cut into two pieces measuring 4 cm wide x 4 cm long to prepare test specimens. The two obtained test specimens were stacked with the functional layer side facing each other and pressed at a temperature of 40°C and a pressure of 5 MPa for 2 minutes to obtain a pressed body. One end of the obtained pressed body was fixed, and the other end of the pressed body was pulled vertically upward at a tensile speed of 50 mm / min. The stress when peeled was measured, and the obtained stress was taken as the blocking strength. The blocking resistance was then evaluated according to the following criteria. The smaller the blocking strength, the better the functional layer suppresses the occurrence of blocking, i.e., the higher the blocking resistance of the functional layer. A: Blocking strength is less than 4N / m B: Blocking strength is 4N / m or more and less than 6N / m C: Blocking strength is 6N / m or more <Heat resistance> The prepared separator (equipped with functional layers on both sides with a heat-resistant region having an average height of 2.0 μm in the stacking direction) was cut into a square measuring 12 cm wide x 12 cm long, and a square measuring 10 cm on each side was drawn inside the resulting square to prepare a test piece. The test piece was then placed in a thermostatic chamber at 150°C and left for 1 hour. The change in the area of ​​the square drawn inside (= {(area of ​​square before leaving - area of ​​square after leaving) / area of ​​square before leaving} × 100%) was calculated as the thermal shrinkage rate and evaluated according to the following criteria. A smaller thermal shrinkage rate indicates that the separator with the functional layer has better heat resistance. A: Heat shrinkage rate is less than 3% B: Heat shrinkage rate is 3% or more and less than 5% C: Heat shrinkage rate is 5% or more and less than 10% D: Heat shrinkage rate is 10% or more <Rate characteristics> The fabricated lithium-ion secondary battery was left standing for 24 hours in an environment at 25°C, and then charged and discharged at 4.35 V and 0.1 C, and discharged at 3.0 V and 0.1 C, at 25°C, to measure the initial capacity C0. Subsequently, the battery was charged and discharged at 4.35 V and 0.1 C, and discharged at 3.0 V and 2 C, at 25°C, to measure the capacity C1. The rate characteristics were evaluated by ΔC = (C0 - C1) / C0 × 100 (%), with a larger value indicating a better rate characteristic of the lithium-ion secondary battery. A: ΔC is 90% or more B: ΔC is 85% or more and less than 90% C: ΔC is 80% or more and less than 85% D: ΔC is less than 80% <Cycle characteristics> After injecting the electrolyte, the fabricated lithium-ion secondary battery was left standing at 25°C for 5 hours. Next, it was charged at 25°C at a constant current of 0.2C to a cell voltage of 3.65V, and then aged at 60°C for 12 hours. Then, it was discharged at 25°C at a constant current of 0.2C to a cell voltage of 3.00V. Then, it was subjected to CC-CV charging at a constant current of 0.2C (upper limit cell voltage 4.20V), and CC discharging at a constant current of 0.2C to 3.00V. This charge / discharge cycle at 0.2C was repeated three times. Thereafter, 100 cycles of charge and discharge were performed at a temperature of 25°C, a cell voltage of 4.20-3.00V, and a charge and discharge rate of 1.0 C. The discharge capacity of the first cycle was defined as X1, and the discharge capacity of the 100th cycle as X2. Then, the discharge capacity X1 and the discharge capacity X2 were used to calculate the capacity retention rate ΔC′=(X2 / X1)×100(%), and the capacity retention rate was evaluated according to the following criteria: A larger value of the capacity retention rate ΔC′ indicates that the lithium ion secondary battery has better cycle characteristics. A: ΔC´ is 93% or more B: ΔC´ is 90% or more and less than 93% C: ΔC´ is less than 90%

[0104] Example 1 <Preparation of Polyester Polymer> 2000 g of BPA-PO (a propylene oxide adduct of bisphenol A, average number of moles added: 2.2 mol) and 800 g of BPA-EO (an ethylene oxide adduct of bisphenol A, average number of moles added: 2.2 mol) as alcohol components, 600 g of fumaric acid and 500 g of trimellitic anhydride as carboxylic acid components, and 4 g of dibutyltin oxide were placed in a 5-liter four-neck flask equipped with a nitrogen inlet tube, a dehydration tube, a stirrer, and a thermocouple, and reacted at 220°C for 8 hours. The reaction was then continued at 8.3 kPa until the softening point of the reactant (measured by the method described below) reached 150°C, yielding a polyester polymer. The resulting polyester polymer had a glass transition temperature of 62°C. -Method for measuring softening point- Using a high-speed flow tester (Shimadzu Corporation, product name "CFT-500D"), 1 g of the sample was heated at a temperature increase rate of 6°C / min, while a load of 1.96 MPa was applied with the plunger to push out a nozzle with a diameter of 1 mm and a length of 1 mm. This produced a plunger descending amount (flow value)-temperature curve of the flow tester, and when the height of the S-shaped curve was defined as h, the temperature corresponding to h / 2 (the temperature at which half of the polymer had flowed out) was taken as the softening point. <Preparation of ester wax (meltable additive)> A 0.5 L four-neck flask equipped with a nitrogen inlet tube, a stirring blade, and a condenser was charged with 18 g (0.13 mol) of pentaerythritol and 104 g (0.52 mol) of lauric acid, and the mixture was reacted at 220°C for 10 hours under a nitrogen stream while distilling off the generated water. 46.5 g of toluene, 32 g of 2-propanol, and 19 g of a 10% aqueous potassium hydroxide solution containing 2.0 equivalents of potassium hydroxide as the acid value were added, and the mixture was stirred at 70°C for 30 minutes. After standing for 30 minutes, the aqueous layer was removed to obtain a crude product. Using 40 parts of ion-exchanged water per 100 parts of the crude product, the crude product was washed four times at 70°C to adjust the pH to 7. The solvent was distilled off from the resulting purified product under heating and reduced pressure conditions, and the product was filtered, solidified, and pulverized to obtain 140 g of pentaerythritol tetralaurate (melting point: 44°C) as an ester wax. <Preparation of adhesive particles> The adhesive particulate material (polyester polymer, ester wax) was granulated by the following procedure using a dissolution suspension method. 100 parts of polyester resin, 10 parts of ester wax, and 230 parts of toluene as an organic solvent were dispersed in a ball mill to obtain a liquid composition. Separately, 480 parts of an aqueous solution of hydroxyapatite (concentration: 5%), 6 parts of an aqueous solution of sodium dodecylbenzenesulfonate (concentration: 1%), and 120 parts of water were mixed together to prepare an aqueous medium. The liquid composition was dispersed in the aqueous medium using a homogenizer. The rotor peripheral speed was adjusted to a range of 6 to 8 m / sec. The resulting dispersion was placed under conditions of a temperature of 50 to 70°C and a pressure of 30 to 150 mmHg to remove toluene. After toluene removal, the composition was cooled and then washed with 12 N hydrochloric acid until the pH reached 2. The composition was then further washed with water, dried, and classified to obtain adhesive particles containing a polyester polymer and an ester wax. The adhesive particles had a volume average particle size of 6.0 μm and an average circularity of 0.97. <Preparation of binder> To a reactor equipped with a stirrer, 70 parts of ion-exchanged water, 0.15 parts of sodium lauryl sulfate (manufactured by Kao Chemical Corporation, "EMAL (registered trademark) 2F") as an emulsifier, and 0.5 parts of ammonium persulfate as a polymerization initiator were supplied, the gas phase was replaced with nitrogen gas, and the temperature was raised to 60°C. Meanwhile, in another container, 50 parts of ion-exchanged water, 0.5 parts of sodium dodecylbenzenesulfonate as a dispersion stabilizer, 94 parts of n-butyl acrylate as a (meth)acrylic acid ester monomer, 2 parts of methacrylic acid as an acid group-containing monomer, and 2 parts of acrylonitrile as a nitrile group-containing monomer, as well as 1 part of allyl methacrylate and 1 part of allyl glycidyl ether as crosslinkable monomers were mixed to prepare a monomer composition. The resulting monomer composition was continuously added to the above-mentioned reactor equipped with a stirrer over 4 hours to carry out polymerization. The reaction was carried out at 60°C during the addition. After the addition was completed, the mixture was stirred at 70°C for an additional 3 hours, and then the reaction was terminated, yielding an aqueous dispersion containing a particulate binder as an acrylic polymer. The resulting binder had a volume average particle diameter of 0.25 μm and a glass transition temperature of -40°C. <Preparation of Functional Layer Composition> 0.5 parts of polyacrylic acid as a water-soluble polymer was added to 100 parts of alumina (volume average particle diameter: 0.5 μm) as heat-resistant fine particles, and ion-exchanged water was added to make the solid content concentration 55%, followed by mixing using a ball mill to obtain an alumina-containing slurry. In addition, 100 parts of the adhesive particles, 0.2 parts of sodium dodecylbenzenesulfonate ("Neopelex G-15" manufactured by Kao Chemical Corporation) as a dispersant, and ion-exchanged water were mixed to obtain an adhesive particle-containing mixed liquid with a solid content of 40%. The alumina-containing slurry and the adhesive particle-containing mixed solution were mixed so that the ratio of alumina to adhesive particles (alumina / adhesive particles) was 70 / 30 by volume (90 / 10 by mass). To the resulting mixed solution, 6 parts (solids equivalent) of the aqueous dispersion containing the binder per 100 parts of alumina, 1.5 parts of carboxymethyl cellulose as a water-soluble polymer (thickener), and ion-exchanged water were added to obtain a functional layer composition (solids concentration: 40%). <Fabrication of separator with functional layer> A polyethylene microporous film (thickness: 12 μm) was prepared as a separator substrate. The functional layer composition obtained above was applied to one side of the prepared separator substrate using a bar coater method. The coating was dried at 50°C. The same operation as above was then performed on the other side of the separator substrate, resulting in a separator with functional layers on both sides of the separator substrate. Each of the two functional layers of the obtained separator had an adhesive region made of adhesive particles and a heat-resistant region made of alumina as heat-resistant fine particles and a binder, and the average height of the heat-resistant region in the stacking direction was 2.0 μm. The separator having functional layers on both sides was then evaluated for low-temperature adhesion, blocking resistance, and heat resistance. The results are shown in Table 1. <Preparation of positive electrode> A mixture of 100 parts of LiCoO2 (volume average particle diameter: 12 μm) as a positive electrode active material, 2 parts of acetylene black (HS-100, manufactured by Denki Kagaku Kogyo Co., Ltd.) as a conductive material, 2 parts of polyvinylidene fluoride (#7208, manufactured by Kureha Corporation) as a binder for the positive electrode composite layer in terms of solid content, and N-methylpyrrolidone as a solvent was mixed to a total solid content of 70%. These components were mixed using a planetary mixer to prepare a positive electrode slurry composition. The positive electrode slurry composition was applied to a 20 μm-thick aluminum foil current collector using a comma coater so that the dried film thickness was approximately 150 μm, and then dried. This drying was performed by transporting the aluminum foil at a speed of 0.5 m / min through an oven at 60°C for 2 minutes. The aluminum foil was then heat-treated at 120°C for 2 minutes to obtain a pre-press positive electrode blank. This pre-press positive electrode blank was rolled using a roll press to obtain a positive electrode having a positive electrode composite layer (thickness: 60 μm). <Preparation of negative electrode> A 5 MPa pressure vessel equipped with a stirrer was charged with 33 parts of 1,3-butadiene, 3.5 parts of itaconic acid, 63.5 parts of styrene, 0.4 parts of sodium dodecylbenzenesulfonate as an emulsifier, 150 parts of ion-exchanged water, and 0.5 parts of potassium persulfate as a polymerization initiator. After thorough stirring, the mixture was heated to 50 °C to initiate polymerization. When the polymerization conversion reached 96%, the reaction was stopped by cooling, yielding a mixture containing a binder (SBR) for the negative electrode composite layer. A 5% aqueous sodium hydroxide solution was added to the mixture containing the binder for the negative electrode composite layer, adjusting the pH to 8, and then the unreacted monomer was removed by heated vacuum distillation. The mixture was then cooled to below 30 °C to obtain an aqueous dispersion containing the desired binder for the negative electrode composite layer. 80 parts of artificial graphite (volume average particle diameter: 15.6 μm) as a negative electrode active material and 16 parts of silicon-based active material SiOx (volume average particle diameter: 4.9 μm) were blended, and 2.5 parts of a 2% aqueous solution of carboxymethylcellulose sodium salt (manufactured by Nippon Paper Industries Co., Ltd., "MAC350HC") as a viscosity modifier, equivalent to solids, and ion-exchanged water were mixed to adjust the solids concentration to 68%, and then further mixed at 25 ° C for 60 minutes. The solids concentration was further adjusted to 62% with ion-exchanged water, and then further mixed at 25 ° C for 15 minutes to obtain a mixed solution. 1.5 parts of the aqueous dispersion containing the above-mentioned binder for the negative electrode composite layer, equivalent to solids, and ion-exchanged water were added to this mixed solution, and the final solids concentration was adjusted to 52%, and then further mixed for 10 minutes to obtain a mixed solution. This mixed solution was degassed under reduced pressure to obtain a negative electrode slurry composition with good fluidity. The negative electrode slurry composition was applied to a 20 μm-thick copper foil current collector using a comma coater so that the dried film thickness was approximately 150 μm, and then dried. This drying was performed by transporting the copper foil at a speed of 0.5 m / min through an oven at 60°C for 2 minutes. The copper foil was then heat-treated at 120°C for 2 minutes to obtain a pre-press negative electrode blank. This pre-press negative electrode blank was rolled using a roll press to obtain a negative electrode having a negative electrode composite layer (thickness: 80 μm). <Fabrication of lithium-ion secondary batteries> The positive electrode prepared as described above was cut into a 49 cm x 5 cm rectangle and placed with the surface on the positive electrode composite layer facing up. A separator (with functional layers on both sides) cut to 120 cm x 5.5 cm was placed on the positive electrode composite layer so that the positive electrode was located on one side of the separator in the longitudinal direction. Furthermore, the negative electrode prepared as described above was cut into a 50 cm x 5.2 cm rectangle and placed on the separator so that the surface on the negative electrode composite layer faced the separator and the negative electrode was located on the other side of the separator in the longitudinal direction. The resulting laminate was then wound around a wound body to obtain a wound body. This wound body was pressed at 50°C and 1 MPa to form a flat body, then wrapped in an aluminum packaging exterior as the battery exterior, and an electrolyte solution [solvent: ethylene carbonate / diethyl carbonate / vinylene carbonate (volume ratio) = 68.5 / 30 / 1.5, electrolyte: LiPF6 concentration 1 mol)] was injected so that no air remained. The opening of the aluminum packaging exterior was then heat-sealed at a temperature of 150°C to produce a wound-type lithium-ion secondary battery with a capacity of 800 mAh. The rate characteristics and cycle characteristics of the obtained lithium ion secondary battery were evaluated, and the results are shown in Table 1.

[0105] Examples 2 to 5 In preparing the adhesive particles, the amount of the ester wax, which is a meltable additive, was changed to 5 parts (Example 2), 20 parts (Example 3), 30 parts (Example 4), and 35 parts (Example 5), respectively. In the same manner as in Example 1, polyester polymers, ester waxes, adhesive particles, binders, functional layer compositions, separators, negative electrodes, positive electrodes, and lithium ion secondary batteries were obtained. Various evaluations were then performed in the same manner as in Example 1. The results are shown in Table 1.

[0106] Example 6 When preparing the ester wax, which is a meltable additive, behenic acid was used instead of lauric acid to obtain pentaerythritol tetrabehenate (melting point: 81°C) as the ester wax. Except for using this ester wax, a polyester polymer, adhesive particles, a binder, a functional layer composition, a separator, a negative electrode, a positive electrode, and a lithium ion secondary battery were obtained in the same manner as in Example 1. Various evaluations were then performed in the same manner as in Example 1. The results are shown in Table 1.

[0107] Example 7 Except for not preparing the ester wax as a meltable additive and not using any meltable additive when preparing the adhesive particles, a polyester polymer, adhesive particles, a binder, a functional layer composition, a separator, a negative electrode, a positive electrode, and a lithium ion secondary battery were obtained in the same manner as in Example 1. Various evaluations were then performed in the same manner as in Example 1. The results are shown in Table 1.

[0108] Example 8 In preparing the adhesive particles, the concentration of the hydroxyapatite aqueous solution was changed to 10% and the volume average particle diameter of the adhesive particles in the laminate was changed to 3 μm. Except for this, a polyester polymer, an ester wax, adhesive particles, a binder, a functional layer composition, a separator, a negative electrode, a positive electrode, and a lithium ion secondary battery were obtained in the same manner as in Example 1. Then, various evaluations were performed in the same manner as in Example 1. The results are shown in Table 1.

[0109] Example 9 In preparing the adhesive particles, the concentration of the hydroxyapatite aqueous solution was changed to 3% and the volume average particle diameter of the adhesive particles in the laminate was changed to 9 μm. Except for this, a polyester polymer, an ester wax, adhesive particles, a binder, a functional layer composition, a separator, a negative electrode, a positive electrode, and a lithium ion secondary battery were obtained in the same manner as in Example 1. Then, various evaluations were performed in the same manner as in Example 1. The results are shown in Table 2.

[0110] Example 10 Except for using a crystalline polyester resin prepared as described below instead of ester wax as the meltable additive, a polyester polymer, adhesive particles, a binder, a functional layer composition, a separator, a negative electrode, a positive electrode, and a lithium ion secondary battery were obtained in the same manner as in Example 1. Various evaluations were then performed in the same manner as in Example 1. The results are shown in Table 2. <Preparation of crystalline polyester resin (melt additive)> A 5L four-neck flask equipped with a nitrogen inlet tube, dehydration tube, stirrer, and thermocouple was charged with sebacic acid as the carboxylic acid component and 1,6-hexanediol as the alcohol component, so that the molar ratio of hydroxyl groups to carboxyl groups (OH / COOH) was 0.85. The mixture was reacted with titanium tetraisopropoxide (500 ppm relative to the resin component) at 180°C for 10 hours, then heated to 200°C and reacted for 3 hours, and then reacted at a pressure of 8.3 kPa for an additional 2 hours to obtain a crystalline polyester resin (melting point: 65°C). It was confirmed that this crystalline polyester resin had a glass transition temperature not in the range of 10°C to 95°C.

[0111] Example 11 In preparing the adhesive particles, a polyester polymer, adhesive particles, binder, functional layer composition, separator, negative electrode, positive electrode, and lithium ion secondary battery were obtained in the same manner as in Example 1, except that 5 parts of paraffin wax (manufactured by Nippon Seiro Co., Ltd., product name "HNP-11", melting point: 68°C) was used instead of 10 parts of ester wax as the meltable additive. Then, various evaluations were performed in the same manner as in Example 1. The results are shown in Table 2.

[0112] (Examples 12 to 13) In preparing the functional layer composition, the alumina-containing slurry and the adhesive particle-containing mixed solution were mixed so that the mixing ratio of the alumina particles to the adhesive particles (alumina particles / adhesive particles) was 80 / 20 by volume (94 / 6 by mass, Example 12) and 55 / 45 by volume (82 / 18 by mass, Example 13), respectively. The polyester polymer, ester wax, adhesive particles, binder, functional layer composition, separator, negative electrode, positive electrode, and lithium-ion secondary battery were obtained in the same manner as in Example 1. Various evaluations were then performed in the same manner as in Example 1. The results are shown in Table 2.

[0113] Example 14 Except for using a polyester polymer prepared as follows, an ester wax, adhesive particles, a binder, a functional layer composition, a separator, a negative electrode, a positive electrode, and a lithium ion secondary battery were obtained in the same manner as in Example 1. Various evaluations were then performed in the same manner as in Example 1. The results are shown in Table 2. <Preparation of Polyester Polymer> A reaction vessel was charged with 143 parts of BPA-PO (a propylene oxide adduct of bisphenol A, average number of moles added: 2.2 mol) as the alcohol component, 133 parts of terephthalic acid and 33 parts of isophthalic acid as carboxylic acid components, and 0.2 parts of dibutyltin oxide. While blowing nitrogen gas into the reaction vessel, the temperature was gradually raised to 180°C to proceed with the condensation reaction for 5 hours, and then the reaction was completed at 230°C to obtain a polyester polymer. The glass transition temperature of the obtained polyester polymer was 56°C.

[0114] Example 15 Except for using adhesive particles prepared as follows, a polyester polymer, an ester wax, a binder, a functional layer composition, a separator, a negative electrode, a positive electrode, and a lithium ion secondary battery were obtained in the same manner as in Example 1. Various evaluations were then performed in the same manner as in Example 1. The results are shown in Table 2. <Preparation of adhesive particles> The adhesive particulate material (polyester polymer, ester wax) was granulated by the emulsion aggregation method according to the following procedure. <<Preparation of Meltable Additive Dispersion>> Example 1 and Example 2 were carried out by mixing 100 parts of an ester wax (meltable additive) obtained in the same manner as in Example 1, 1 part of an anionic surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., product name "Neogen (registered trademark) RK"), and 350 parts of ion-exchanged water, heating the mixture to 100°C, dispersing the mixture using a homogenizer (Ultra Turrax T50 manufactured by IKA), and then dispersing the mixture using a Manton-Gaulin high-pressure homogenizer (manufactured by Gaulin), to obtain a meltable additive dispersion (solid concentration: 20%) in which an ester wax having a volume average particle size of 200 nm was dispersed. <<Preparation of polymer particle dispersion>> A vessel equipped with a temperature control means and a nitrogen substitution means was charged with 40 parts of ethyl acetate and 25 parts of 2-butanol to prepare a mixed solvent, and then 100 parts of the polyester polymer obtained in the same manner as in Example 1 was gradually added and dissolved therein. Further, a 10% by mass aqueous ammonia solution (equivalent to three times the molar amount of the acid value of the polyester polymer) was added and stirred for 30 minutes to prepare a mixed solution. Next, the atmosphere inside the vessel was replaced with dry nitrogen, the temperature was maintained at 40°C, and 400 parts of ion-exchanged water was added dropwise at a rate of 2 parts / minute while stirring the mixture, to carry out emulsification. After the addition was completed, the emulsion was returned to room temperature (20°C or higher and 25°C or lower), and dry nitrogen was bubbled through the emulsion for 48 hours while stirring to reduce the ethyl acetate and 2-butanol concentrations to 1,000 ppm or less. Further, ion-exchanged water was added to adjust the solids concentration to 20%, yielding a polymer particle dispersion in which polymer particles having a volume average particle size of 200 nm were dispersed. <<Emulsification aggregation>> An apparatus was prepared in which a round flask (made of stainless steel) and a container A (a polyester bottle) were connected by a tube pump A, and the solution contained in the container A was sent to the flask by driving the tube pump A, and the container A and a container B were connected by a tube pump B, and the solution contained in the container B was sent to the container A by driving the tube pump B. The following operations were carried out using this apparatus. 500 parts of the polymer particle dispersion obtained as described above and an anionic surfactant (product name "TaycaPower (registered trademark)") were placed in a round flask of the above-mentioned apparatus, and after 0.1 N nitric acid was added to adjust the pH to 3.5, 30 parts of an aqueous nitric acid solution with a polyaluminum chloride concentration of 10 mass % was added. Subsequently, the mixture was dispersed at 30°C using a homogenizer (Ultra Turrax T50 manufactured by IKA), and the particle size of the aggregated particles was grown while the temperature was raised in a heating oil bath at a rate of 1°C every 30 minutes. Meanwhile, 150 parts of the polymer particle dispersion obtained as described above were placed in container A of the above-mentioned apparatus, and 25 parts of the meltable additive dispersion obtained as described above were placed in container B. Next, the pumping rate of tube pump A was set to 0.70 parts / min, and the pumping rate of tube pump B was set to 0.14 parts / min. Once the temperature inside the round flask during aggregate particle formation reached 37.0°C, tube pumps A and B were driven to start feeding each dispersion. As a result, the concentration of the meltable additive was gradually increased, and the mixed dispersion in which the polymer particles and the meltable additive were dispersed was sent from container A to the round flask during aggregate particle formation. After the transfer of each dispersion liquid to the round flask was completed and the temperature inside the round flask reached 48°C, the temperature was maintained for 30 minutes. Then, 50 parts of the polymer particle dispersion obtained as described above was slowly added to a round flask and held for 1 hour. Next, 0.1 N aqueous sodium hydroxide was added to adjust the pH to 8.5, and the mixture was heated to 85°C with continuous stirring and held for 5 hours. The mixture was then cooled to 20°C at a rate of 20°C / min, filtered, thoroughly washed with ion-exchanged water, and then dried to obtain adhesive particles containing a polyester polymer and an ester wax (the amount of ester wax was 10 parts per 100 parts of polyester polymer). The volume-average particle diameter of the adhesive particles was 6.0 μm and the average circularity was 0.96.

[0115] Example 16 Except for using adhesive particles prepared as follows, a polyester polymer, an ester wax, a binder, a functional layer composition, a separator, a negative electrode, a positive electrode, and a lithium ion secondary battery were obtained in the same manner as in Example 1. Various evaluations were then performed in the same manner as in Example 1. The results are shown in Table 2. <Preparation of adhesive particles> The adhesive particulate material (polyester polymer, ester wax) was granulated by the following procedure using a grinding method. 100 parts of polyester polymer and 10 parts of ester wax were melt-kneaded using a co-rotating twin-screw extruder (total length of kneading section: 1560 mm, screw diameter: 42 mm, barrel inner diameter: 43 mm), then cooled and coarsely pulverized. During melt-kneading, the raw material was fed to the extruder at a rate of 10 kg / h, and the average residence time was approximately 18 seconds. The coarsely pulverized material was then pulverized using a jet mill and classified to obtain adhesive particles containing a polyester polymer and an ester wax. The adhesive particles had a volume average particle size of 6.0 μm and an average circularity of 0.94.

[0116] Example 17 Except for using adhesive particles prepared as follows, a polyester polymer, an ester wax, a binder, a functional layer composition, a separator, a negative electrode, a positive electrode, and a lithium ion secondary battery were obtained in the same manner as in Example 1. Various evaluations were then performed in the same manner as in Example 1. The results are shown in Table 3. <Preparation of adhesive particles> <<Preparation of Monomer Composition>> 4.7 parts of the polyester polymer obtained in the same manner as in Example 1, 61.2 parts of styrene as an aromatic monovinyl monomer, 34.1 parts of n-butyl acrylate as a (meth)acrylic acid ester monomer, and 0.01 parts of divinylbenzene as a crosslinkable monomer were mixed together. 12 parts of the ester wax obtained in the same manner as in Example 1 was further added to the resulting mixture and mixed again to prepare a monomer composition. <<Preparation of colloidal dispersion containing dispersion stabilizer (metal hydroxide)>> A colloidal dispersion containing magnesium hydroxide as a dispersion stabilizer (metal hydroxide) was prepared by gradually adding, with stirring, an aqueous solution prepared by dissolving 5.6 parts of sodium hydroxide in 50 parts of ion-exchanged water (aqueous sodium hydroxide solution) to an aqueous solution prepared by dissolving 8.0 parts of magnesium chloride in 200 parts of ion-exchanged water (aqueous magnesium chloride solution). <<Suspension polymerization>> The above-mentioned monomer composition was added to the above-mentioned colloidal dispersion and further stirred, and then 2.0 parts of t-butylperoxy-2-ethylhexanoate (manufactured by NOF Corporation, product name "Perbutyl O") as a polymerization initiator was added to obtain a mixed solution. The obtained mixed solution was subjected to high-shear stirring at a rotation speed of 15,000 rpm for 1 minute using an in-line emulsifying disperser (manufactured by Pacific Machinery Works, product name "Cavitron") to form droplets of the monomer composition in the colloidal dispersion. The colloidal dispersion in which droplets of the monomer composition had been formed was placed in a reactor, heated to 90° C., and subjected to a polymerization reaction for 5 hours to obtain an aqueous dispersion containing adhesive particles. <<Drying>> Further, while stirring the aqueous dispersion containing the adhesive particles, sulfuric acid was added dropwise at room temperature (25°C) and acid washing was performed until the pH reached 6.5 or less. Next, filtration and separation were performed, and 500 parts of ion-exchanged water was added to the obtained solid matter to re-slurry it, and the water washing treatment (washing, filtration, and dehydration) was repeated several times. Then, filtration and separation were performed, and the obtained solid matter was placed in a container of a dryer and dried at 40°C for 48 hours to obtain adhesive particles. The adhesive particles contained an adhesive polymer having a core-shell structure with a core portion made of an aromatic monovinyl polymer and a shell portion made of a polyester polymer, and an ester wax.

[0117] Example 18 In preparing the functional layer composition, a polyester polymer, an ester wax, adhesive particles, a binder, a functional layer composition, a separator, a negative electrode, a positive electrode, and a lithium ion secondary battery were obtained in the same manner as in Example 1, except that organic fine particles prepared as follows were used instead of alumina particles. Various evaluations were then performed in the same manner as in Example 1. The results are shown in Table 3. <Preparation of organic fine particles (heat-resistant fine particles)> In a reactor A equipped with a stirrer, 0.20 parts of sodium dodecyl sulfate, 0.30 parts of ammonium persulfate, and 180 parts of ion-exchanged water were mixed to form a mixture, and the mixture was heated to 65° C. Meanwhile, in a separate vessel, 80.0 parts of n-butyl acrylate as a (meth)acrylic acid ester monomer, 10.0 parts of methacrylic acid as an acid group-containing monomer, 10.0 parts of acrylonitrile as a nitrile group-containing monomer, 0.8 parts of sodium dodecyl sulfate, and 40 parts of ion-exchanged water were mixed to prepare a monomer composition for seed particles. This seed particle monomer composition was continuously added to the above-mentioned reactor A over a period of 4 hours to carry out a polymerization reaction. The temperature inside the reactor was maintained at 65°C during the continuous addition of the seed particle monomer composition. After the continuous addition was completed, the polymerization reaction was continued for an additional 3 hours at 80°C. This resulted in an aqueous dispersion of seed particles. The volume average particle diameter of the seed particles was measured in the same manner as for the binder and was found to be 120 nm. Next, 20 parts of the aqueous dispersion of the seed particles (based on solids content) (16 parts n-butyl acrylate units, 2 parts methacrylic acid units, and 2 parts acrylonitrile units), 80 parts ethylene glycol dimethacrylate (Kyoeisha Chemical Co., Ltd., product name "Light Ester EG") as a crosslinking monomer, 0.8 parts sodium dodecylbenzenesulfonate, 3.2 parts t-butylperoxy-2-ethylhexanoate (NOF Corporation, product name "Perbutyl O") as a polymerization initiator, and 160 parts ion-exchanged water were added to a reactor equipped with a stirrer, and the mixture was stirred at 35°C for 12 hours, allowing the crosslinking monomer and polymerization initiator to be completely absorbed into the seed particles. The temperature inside the reactor was then maintained at 90°C, and a polymerization reaction (seed polymerization) was carried out for 5 hours. Next, steam was introduced to remove unreacted monomers and initiator decomposition products, and an aqueous dispersion of organic fine particles (volume average particle diameter: 0.5 μm) was obtained. The glass transition temperature of the obtained organic fine particles was measured in the same manner as for the adhesive particles and binder, but no peak was observed within the measurement temperature range (-100 ° C to 200 ° C). This confirmed that the glass transition temperature of the organic fine particles was above 200 ° C.

[0118] (Comparative Example 1) Except for not preparing the polyester polymer and ester wax and using adhesive particles prepared as follows, a binder, a functional layer composition, a separator, a negative electrode, a positive electrode, and a lithium ion secondary battery were obtained in the same manner as in Example 1. Various evaluations were then performed in the same manner as in Example 1. The results are shown in Table 3. <Preparation of adhesive particles> A monomer composition was prepared by mixing 81.9 parts of styrene as an aromatic monovinyl monomer, 18 parts of 2-ethylhexyl acrylate as a (meth)acrylic acid ester monomer, and 0.1 part of ethylene glycol dimethacrylate as a crosslinkable monomer. A colloidal dispersion was prepared in the same manner as in Example 17, except that the above monomer composition was used, and then suspension polymerization and drying were carried out to obtain adhesive particles.

[0119] (Comparative Example 2) Except for not preparing the polyester polymer and ester wax and using adhesive particles prepared as follows, a binder, a functional layer composition, a separator, a negative electrode, a positive electrode, and a lithium ion secondary battery were obtained in the same manner as in Example 1. Various evaluations were then performed in the same manner as in Example 1. The results are shown in Table 3. <Preparation of adhesive particles> A monomer composition was prepared by mixing 60.9 parts of styrene as an aromatic monovinyl monomer, 39 parts of 2-ethylhexyl acrylate as a (meth)acrylic acid ester monomer, and 0.1 part of ethylene glycol dimethacrylate as a crosslinkable monomer. A colloidal dispersion was prepared in the same manner as in Example 17, except that the above monomer composition was used, and then suspension polymerization and drying were carried out to obtain adhesive particles.

[0120] (Comparative Example 3) Except for not preparing the polyester polymer and ester wax and using adhesive particles prepared as follows, a binder, a functional layer composition, a separator, a negative electrode, a positive electrode, and a lithium ion secondary battery were obtained in the same manner as in Example 1. Various evaluations were then performed in the same manner as in Example 1. The results are shown in Table 3. <Preparation of adhesive particles> 81.9 parts of styrene as an aromatic monovinyl monomer, 18 parts of 2-ethylhexyl acrylate as a (meth)acrylic acid ester monomer, and 0.1 parts of ethylene glycol dimethacrylate as a crosslinkable monomer were mixed together. 5 parts of polyethylene wax (melting point: 95°C, number average molecular weight: 7,300) was added to the resulting mixture and mixed again to prepare a monomer composition. A colloidal dispersion was prepared in the same manner as in Example 17, except that the above monomer composition was used, and then suspension polymerization and drying were carried out to obtain adhesive particles.

[0121] Comparative Example 4 Except for not using alumina particles when preparing the functional layer composition, a polyester polymer, an ester wax, adhesive particles, a binder, a functional layer composition, a separator, a negative electrode, a positive electrode, and a lithium ion secondary battery were obtained in the same manner as in Example 1. Various evaluations were then performed in the same manner as in Example 1. The results are shown in Table 3.

[0122] (Comparative Example 5) Except for using the polyester polymer prepared as follows, an ester wax, adhesive particles, a binder, a functional layer composition, a separator, a negative electrode, a positive electrode, and a lithium ion secondary battery were obtained in the same manner as in Example 1. Various evaluations were then performed in the same manner as in Example 1. The results are shown in Table 3. <Preparation of Polyester Polymer> A mixture consisting of 1661 parts of terephthalic acid as a carboxylic acid component, 1316 parts of bisphenoxyethanolfluorene (BPEF) as an alcohol component, 1094 parts of neopentyl glycol, and 2.7 parts of trimethylolpropane (terephthalic acid:BPEF:neopentyl glycol:trimethylolpropane=100:30:105:0.2 (molar ratio)) was stirred in an autoclave for 3 hours under controlled conditions of 0.3 MPa and 260°C. After the pressure was released, the reaction was carried out for 3 hours at normal pressure and 260°C. The temperature was then raised to 270°C, and 6.8 parts of tetrabutyl titanate (20 x 10 per mole of terephthalic acid) was added as a catalyst. -4 The pressure in the system was gradually reduced to 13 Pa after 1.5 hours, and the reaction was continued. Condensation was continued until an appropriate viscosity was achieved, and a polyester polymer pellet was obtained using a strand cutter. The glass transition temperature of the resulting polyester polymer was 100°C.

[0123] (Comparative Example 6) Except for using the polyester polymer prepared as follows, an ester wax, adhesive particles, a binder, a functional layer composition, a separator, a negative electrode, a positive electrode, and a lithium ion secondary battery were obtained in the same manner as in Example 1. Various evaluations were then performed in the same manner as in Example 1. The results are shown in Table 3. <Preparation of Polyester Polymer> 900 parts of ethylene glycol as the alcohol component, 2000 parts of dimethyl terephthalate as the carboxylic acid component, and 4 parts of dibutyltin oxide were placed in a 5-liter four-neck flask equipped with a nitrogen inlet tube, a dehydration tube, a stirrer, and a thermocouple. The mixture was heated from 165°C to 200°C over 70 minutes and allowed to react. One part of trimethyl phosphate was then added, and the mixture was allowed to react for 35 minutes. 1000 parts of dodecanedioic acid as the carboxylic acid component was then added, and the mixture was heated to 240°C over 30 minutes and allowed to react. The mixture was then heated to 265°C and allowed to react for 4 hours at 0.1 mmHg, yielding a polyester polymer. The glass transition temperature of the resulting polyester polymer was 0°C.

[0124] In addition, in Tables 1 to 3 shown below, "PES polymer" refers to a polyester polymer; "Aromatic" refers to an aromatic vinyl polymer; "Additive" refers to a meltable additive; "PES resin" refers to a crystalline polyester resin, "Acrylic" refers to an acrylic polymer; "Organic" refers to organic particles; "Particle diameter of adhesive particles / height of heat-resistant region" indicates the volume average particle diameter of adhesive particles / average height of heat-resistant region in the stacking direction, "PE" indicates a microporous membrane made of polyethylene.

[0125] [Table 1]

[0126] [Table 2]

[0127] [Table 3]

[0128] It is clear from Tables 1 to 3 that the laminates of Examples 1 to 18 can be used favorably as separators excellent in low-temperature adhesion, blocking resistance, and heat resistance. It is also clear that lithium ion secondary batteries excellent in rate characteristics and cycle characteristics were obtained in Examples 1 to 18. [Industrial Applicability]

[0129] According to the present invention, it is possible to provide a laminate for an electrochemical device that can be advantageously used as a device component having excellent blocking resistance and low-temperature adhesion, and an electrochemical device including the laminate for an electrochemical device as a device component. [Explanation of symbols]

[0130] 100 laminate 10 Functional Layers 11 Adhesion area 11a Adhesive particles 12 Heat resistant area 12a Heat-resistant fine particles 12b Binder 20 Base material T Height of heat-resistant area in the stacking direction D Particle diameter of adhesive particles

Claims

1. A laminate for an electrochemical device comprising a substrate and a functional layer disposed on the substrate, the functional layer contains heat-resistant fine particles, adhesive particles containing an adhesive polymer, and a binder; the adhesive polymer contains a polyester polymer having a glass transition temperature in the range of 10°C or higher and 95°C or lower, When viewed from above from the functional layer side, the functional layer has an adhesive region made of the adhesive particles and a heat-resistant region made of the heat-resistant fine particles and the binder, The adhesive particles have a volume average particle diameter greater than an average height in the stacking direction of the heat-resistant region.

2. 2. The laminate for an electrochemical device according to claim 1, wherein the adhesive particles further contain a meltable additive having a melting point in the range of 40°C or higher and 95°C or lower.

3. 3. The laminate for an electrochemical element according to claim 2, wherein the meltable additive is at least one selected from the group consisting of ester wax, paraffin wax, and a crystalline polyester resin having a glass transition temperature not in the range of 10°C or higher and 95°C or lower.

4. 4. The laminate for an electrochemical device according to claim 1, wherein the adhesive particles have a volume average particle size of 1.0 μm or more and 10.0 μm or less.

5. 5. The laminate for an electrochemical device according to claim 1, wherein the ratio of the volume average particle diameter of the adhesive particles to the average height in the stacking direction of the heat-resistant region is 1.1 or more and 10.0 or less.

6. 6. The laminate for an electrochemical element according to claim 1, wherein the volume ratio of the content of the heat-resistant fine particles to the content of the adhesive particles in the functional layer is 55 / 45 or more and 95 / 5 or less.

7. 7. The laminate for an electrochemical device according to claim 1, wherein the adhesive particles have an average circularity of 0.90 or more and 0.99 or less.

8. 8. The laminate for an electrochemical device according to claim 1, wherein the heat-resistant fine particles are inorganic fine particles.

9. 9. The laminate for an electrochemical device according to claim 8, wherein the inorganic fine particles include at least one selected from the group consisting of alumina particles, boehmite particles, barium sulfate particles, and magnesium hydroxide particles.

10. An electrochemical device comprising the laminate for an electrochemical device according to any one of claims 1 to 9.

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