JP2019089908A - Adhesive sheet for cell and lithium ion cell - Google Patents

Abstract

To provide an adhesive sheet for cell excellent in insulation properties even after high temperature heating, and a lithium ion cell using the adhesive sheet for cell.SOLUTION: There is provided an adhesive sheet for cell having a substrate 11, a hard coat layer 12 arranged on one surface side of the substrate 11, and an adhesive layer 13 arranged on a surface side opposite to the substrate 11 in the hard coat later 12, in which the hard coat layer 12 is formed form a composition for hard coat layer containing an inorganic oxide fine particle having insulation properties, and values represented by X and Y satisfies following Condition 1 and Condition 2, wherein thickness of the hard coat layer 12 is X μm, and a value obtained by reducing haze value (%) of the substrate 11 from haze value (%) of a laminate of the substrate 11 and the hard coat layer 12 is Y. (Condition 1) Y≥-12X+30. (Condition 2) X>0.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a pressure-sensitive adhesive sheet for batteries and a lithium ion battery produced using the pressure-sensitive adhesive sheet for batteries.

  In some batteries, a strip-shaped laminate in which a positive electrode, a negative electrode, and a separator positioned between them are stacked is accommodated inside in a wound state. The positive electrode and the negative electrode are respectively connected to electrode extraction tabs made of a conductor, and the positive electrode and the negative electrode are electrically connected to the positive electrode terminal and the negative electrode terminal of the battery through these electrode extraction tabs, respectively. .

  A pressure-sensitive adhesive tape is used to fasten the laminate and fix the electrode extraction tab to the electrode. Patent documents 1 and 2 disclose such an adhesive tape. These pressure-sensitive adhesive tapes consist of a substrate and a pressure-sensitive adhesive layer provided on one side of the substrate.

Patent No. 5639733 JP, 2011-138632, A

  The pressure-sensitive adhesive tape used inside the battery may come in contact with the electrolytic solution filled inside the battery or may be exposed to heat generated during charge and discharge. Particularly in recent years, development of small-sized and high-performance batteries has been promoted, and adhesive tapes used inside the batteries are exposed to more severe conditions.

  Although the substrate constituting the adhesive tape used inside the battery is generally made of an insulating material, when such a substrate is exposed to a high temperature, carbonization, combustion and decomposition (hereinafter referred to as "carbonization etc." May occur, and the entire substrate may be transformed into a conductor. In this case, the adhesive tape becomes conductive, and in the battery in which the adhesive tape is used, a short circuit or thermal runaway may occur due to the adhesive tape, and a serious accident may occur. Therefore, the adhesive tape used inside the battery is required to maintain insulation even when exposed to high temperatures. Moreover, since the adhesive tape used inside a battery may be immersed in electrolyte solution, maintaining insulation also in the state immersed in electrolyte solution for a long time is requested | required.

  The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a pressure-sensitive adhesive sheet for a battery which is excellent in insulation even after high-temperature heating and a lithium ion battery using such a pressure-sensitive adhesive sheet. .

In order to achieve the above object, firstly, according to the present invention, a substrate, a hard coat layer provided on one surface of the substrate, and a surface of the hard coat layer opposite to the substrate are provided. And a pressure-sensitive adhesive layer provided on the hard coat layer, wherein the hard coat layer is formed from a composition for hard coat layer containing inorganic oxide fine particles having an insulating property, and the thickness of the hard coat layer is Assuming that X is a value obtained by subtracting the haze value (%) of the base material from the haze value (%) of the laminate of the base material and the hard coat layer as Y, the X and Y represent the table. The values to be calculated are the following condition 1 and condition 2
(Condition 1) Y − -12X + 30
(Condition 2) X> 0
And a pressure-sensitive adhesive sheet for a battery (invention 1). In the present specification, a sheet also includes the concept of a tape. Moreover, the hard-coat layer in this specification means the layer which consists of material harder than a base material, and does not mean the layer which exists in the outermost layer of a film.

  The pressure-sensitive adhesive sheet for a battery according to the above invention (Invention 1) has a hard coat layer formed of a composition for hard coat layer containing inorganic oxide fine particles having insulating properties, and also has a thickness of the hard coat layer, When the value obtained by subtracting the haze value of the base material from the haze value of the laminate of the base material and the hard coat layer satisfies the conditions 1 and 2 described above, the insulation property is excellent even after high temperature heating.

  In the said invention (invention 1), it is preferable that the said inorganic oxide fine particles are metal oxide fine particles (invention 2).

In the above invention (invention 1), the hard coat layer, the inorganic oxide particles, 0.01 cm ³ / ^{m 2} or more, preferably contains ^{7 cm} 3 / ^{m 2} or less (invention 3).

  Second, in the present invention, lithium is characterized in that two or more conductors are in contact with each other by using the above-mentioned adhesive sheet for batteries (inventions 1 to 3) inside the battery. An ion battery is provided (invention 4).

  According to the pressure-sensitive adhesive sheet for batteries and the lithium ion battery according to the present invention, the pressure-sensitive adhesive sheet for batteries is excellent in insulation property even after high temperature heating.

It is sectional drawing of the adhesive sheet for batteries which concerns on one Embodiment of this invention. It is a partial section disassembled perspective view of a lithium ion battery concerning one embodiment of the present invention. It is an expanded perspective view of an electrode body of a lithium ion battery concerning one embodiment of the present invention. Graph showing the relationship between the thickness of the hard coat layer and the value obtained by subtracting the haze value of the substrate from the haze value of the laminate of the substrate and the hard coat layer in the pressure-sensitive adhesive sheets for batteries of Examples and Comparative Examples. It is.

Hereinafter, embodiments of the present invention will be described.
[Adhesive sheet for battery]
As shown in FIG. 1, a battery pressure-sensitive adhesive sheet 1 according to an embodiment of the present invention includes a substrate 11, a hard coat layer 12 provided on one surface of the substrate 11, and a hard coat layer 12. It is comprised from the adhesive layer 13 provided in the opposite side to the base material 11, and the peeling sheet 14 provided in the opposite side to the hard-coat layer 12 in the adhesive layer 13. As shown in FIG.

  Here, the “pressure-sensitive adhesive sheet for battery” in the present specification is a pressure-sensitive adhesive sheet used in a portion which may come in contact with an electrolytic solution in the manufacture of a battery, preferably a pressure-sensitive adhesive sheet used inside a battery It may be an adhesive sheet for battery interiors. The battery is preferably a non-aqueous battery. Therefore, it is preferable that the electrolyte used for the said battery is a non-aqueous electrolyte. The pressure-sensitive adhesive sheet for a battery in the present specification is preferably a pressure-sensitive adhesive sheet attached to a portion which may be immersed in the electrolyte or a portion which may come in contact with the electrolyte inside the non-aqueous battery. It is particularly preferable that the adhesive sheet for a battery for tab attachment. A lithium ion battery is particularly preferable as the non-aqueous battery.

  The hard coat layer 12 in the pressure-sensitive adhesive sheet 1 for a battery according to the present embodiment is formed of a composition for a hard coat layer containing inorganic oxide fine particles having an insulating property. As a result, inorganic oxide fine particles are present in the hard coat layer 12, and the battery pressure-sensitive adhesive sheet 1 has insulation. As the thickness of the hard coat layer 12 increases, the amount of inorganic oxide fine particles present per unit area increases, and the insulating property also improves.

Moreover, in the adhesive sheet 1 for batteries which concerns on this embodiment, the thickness of the hard-coat layer 12 shall be X micrometer, and the haze value (%) of the laminated body of the base material 11 and the hard-coat layer 12 is a haze value of the base material 11. Assuming that a value obtained by subtracting (%) is Y, the numerical values represented by the X and Y are the following condition 1 and condition 2
(Condition 1) Y − -12X + 30
(Condition 2) X> 0
Meet. The method for measuring the haze value (%) of the laminate of the substrate 11 and the hard coat layer 12 and the haze value (%) of the substrate 11 is as described in the test examples described later.

  The above Y is one in which the haze value of the hard coat layer 12 is reflected. The haze value of the hard coat layer 12 is strongly influenced by the dispersion state of the inorganic oxide fine particles in the hard coat layer 12. That is, the better the dispersed state of the inorganic oxide fine particles in the hard coat layer 12, the lower the haze value, and the lower the dispersed state, the higher the haze value.

  Here, the inventors of the present invention have better insulation properties of the pressure-sensitive adhesive sheet 1 for battery as the dispersed state of the inorganic oxide fine particles in the hard coat layer 12 is lower, that is, as the haze value of the hard coat layer 12 is higher. I found it to be. The inventors have also found a condition under which excellent insulation can be achieved by the balance between such action and the action of improving the insulation property as the thickness of the hard coat layer 12 is thicker as described above. The condition is the condition 1 described above.

  In condition 1, when the thickness of the hard coat layer 12 is relatively thick (that is, when X is relatively large), the hard coat layer 12 has the effect of improving the insulation as the thickness of the hard coat layer 12 increases. It is shown that good insulation is achieved regardless of the haze value of (ie, the value of Y). In condition 1, when the thickness of the hard coat layer 12 is relatively thin (that is, when X is relatively small), it is difficult to obtain the effect of improving the insulation as the thickness of the hard coat layer 12 increases. Therefore, it is shown that excellent insulation can be achieved by setting the haze value of the hard coat layer 12 to a relatively high value (that is, by relatively increasing the value of Y). By these, the adhesive sheet 1 for batteries which concerns on this embodiment which satisfy | fills the said condition 1 becomes the thing excellent in insulation at least in a normal state. As to condition 2, it is confirmed that the hard coat layer 12 is present, that is, the hard coat layer 12 has a thickness.

  In addition, in the battery pressure-sensitive adhesive sheet 1 according to the present embodiment, even when the matrix (organic component) in the base material 11 or the hard coat layer 12 is carbonized by being exposed to high temperature, the inorganic material having insulating properties. Since the oxide particles remain as an insulating film, the insulation of the battery pressure-sensitive adhesive sheet 1 itself is secured. Furthermore, a high voltage is partially applied to the battery adhesive sheet 1 and a current flows in the thickness direction with respect to the battery adhesive sheet 1 to change the path of the current in the base material 11 to a conductor path. Even when the matrix in the coating layer 12 is carbonized along the path of the current, the inorganic oxide fine particles having an insulating property are present as an insulator in the path, so the insulating sheet 1 for the battery adhesive sheet itself Sex is secured. Furthermore, in the battery pressure-sensitive adhesive sheet 1, the hard coat layer 12 and hence the insulating film are present at a position closer to the adherend, so it is more difficult to form a bypass path of the conductor path due to dielectric breakdown. Become.

  That is, the pressure-sensitive adhesive sheet 1 for a battery according to the present embodiment is excellent in the insulation property even in the normal state even when heated at a high temperature even when the hard coat layer 12 is present. In the battery using the pressure-sensitive adhesive sheet 1 according to the present embodiment having the above-described function and effect, the reduction in performance caused by the pressure-sensitive adhesive sheet is suppressed, and the malfunction, thermal runaway and short circuit of the battery are suppressed. It will be highly sexual.

  The dispersed state of the inorganic oxide fine particles in the hard coat layer 12 is the composition for the hard coat layer for forming the hard coat layer 12 (when the composition for the hard coat layer is mixed with a solvent) The dispersion can be adjusted by controlling the dispersion state of the inorganic oxide fine particles in the coating solution obtained thereby. For example, it can be adjusted according to stirring conditions or ultrasonic treatment conditions at the time of preparing the composition for hard coat layer (or the above-mentioned coating solution), surface treatment conditions of inorganic oxide fine particles, addition conditions of a dispersant, and the like. Furthermore, the dispersion state adjusted as described above can also be maintained by adjusting the viscosity of the composition for hard coat layer (or the above-mentioned coating solution).

Furthermore, in the battery pressure-sensitive adhesive sheet 1 according to the present embodiment, the above-described numerical value represented by X is the following condition 3
(Condition 3) X ≦ 5.0
It is preferable to satisfy In other words, in the battery pressure-sensitive adhesive sheet 1 according to the present embodiment, it is preferable to satisfy the condition 3 together with the conditions 1 and 2 described above. When the pressure-sensitive adhesive sheet 1 for battery satisfies the condition 3, that is, when the thickness of the hard coat layer 12 is 5.0 μm or less, curing shrinkage occurs when the hard coat layer 12 is formed on the substrate 11 Even in this case, the occurrence of curling is effectively suppressed. Further, in the battery pressure-sensitive adhesive sheet 1 according to the present embodiment, by satisfying the conditions 1 and 2 described above, it is effective even when the hard coat layer 12 has a relatively small thickness as described above. Can exhibit insulation.

  In addition, regarding the value of X described above, the hard coat is obtained from the viewpoint of being able to effectively block the permeation of the hard coat layer 12 by the electrolytic solution while the insulation of the pressure-sensitive adhesive sheet 1 for battery becomes more excellent. The thickness (X μm) of the layer 12 is preferably 0.3 μm or more, and particularly preferably 0.7 μm or more. The upper limit of the thickness (X μm) of the hard coat layer 12 is not particularly limited, but is preferably less than 2.5 μm, particularly preferably less than 2 μm, and further preferably 1.8 μm or less Is preferred. According to the pressure-sensitive adhesive sheet 1 for a battery according to the present embodiment, excellent insulation can be achieved by satisfying the above-described condition 1 even when the thickness of the hard coat layer 12 is thus thin. it can.

  Furthermore, with respect to the value of Y described above, the value of Y is preferably 65 or less, particularly from the viewpoint that the scratch resistance of the battery pressure-sensitive adhesive sheet 1 and the adhesion to the adherend become better. It is preferably 55 or less, more preferably 45 or less.

1. Each component 1-1. Substrate In the battery adhesive sheet 1 according to the present embodiment, the substrate 11 preferably has a high minimum voltage causing insulation breakdown, for example, the voltage is preferably 1 kV or more, particularly 2 kV or more Is preferably 5 kV or more. When the voltage is 1 kV or more, dielectric breakdown of the base 11 is unlikely to occur, and the reliability of the battery pressure-sensitive adhesive sheet 1 becomes higher.

  Moreover, it is preferable that the base material 11 has the flame retardance which satisfy | fills the flame-retardant level V-0 of UL94 specification. Since the base material 11 has such a flame retardance, even when heat is generated by the use of a normal battery, modification and deformation of the base material 11 are suppressed. In addition, even if the battery has a defect and generates heat excessively, ignition and combustion of the base material 11 are suppressed, and a serious accident is prevented.

  The material of the substrate 11 can be appropriately selected from the viewpoints of insulation, flame retardancy, heat resistance, reactivity with the electrolyte, permeability of the electrolyte, and the like. In particular, as the substrate 11, it is preferable to use a resin film. Examples of the resin film include polyester films such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate, polyolefin films such as polyethylene film and polypropylene film, and films containing nitrogen in the main chain such as polyamide film, polyimide film, and polyamideimide film. Film consisting of uniting, cellophane, diacetyl cellulose film, triacetyl cellulose film, acetyl cellulose butyrate film, polyvinyl chloride film, polyvinylidene chloride film, polyvinyl alcohol film, ethylene-vinyl acetate copolymer film, polystyrene film, polycarbonate film , Polymethylpentene film, polysulfone film, polyether ether Ketone film, polyethersulfone film, polyetherimide film, fluorine resin film, acrylic resin film, polyurethane resin film, norbornene polymer film, cyclic olefin polymer film, cyclic conjugated diene polymer film, vinyl alicyclic A resin film such as a hydrocarbon polymer film or a laminated film thereof can be mentioned. In particular, from the viewpoint of insulation and flame retardancy, a film of a polymer containing nitrogen in the main chain (which may contain components other than the polymer as described in the present specification) is preferred, and particularly the main chain. The film of the polymer having a nitrogen-containing ring structure is preferred, and further, the film of a polymer having a nitrogen-containing ring structure and an aromatic ring structure in the main chain is preferred. Specifically, for example, a polyimide film, a polyetherimide film or a polyamideimide film is preferable, and among these, a polyimide film which is particularly excellent in insulation and flame retardancy is preferable.

  The thickness of the substrate 11 is preferably 5 μm or more, particularly preferably 10 μm or more, and further preferably 15 μm or more. The thickness of the substrate 11 is preferably 200 μm or less, particularly preferably 100 μm or less, and further preferably 40 μm or less. When the thickness of the substrate 11 is 5 μm or more, the substrate 11 is given appropriate rigidity, and curling occurs even when curing shrinkage occurs when the hard coat layer 12 is formed on the substrate 11 The occurrence is effectively suppressed. In addition, when the thickness of the substrate 11 is 200 μm or less, the battery pressure-sensitive adhesive sheet 1 has appropriate flexibility, and on the surface where a step is present as in the case of fixing the electrode and the electrode extraction tab. Even when the battery pressure-sensitive adhesive sheet 1 is attached, the step can be favorably followed.

1-2. Hard Coat Layer (1) Composition of Hard Coat Layer The hard coat layer 12 of the pressure-sensitive adhesive sheet 1 for a battery according to this embodiment is formed of a composition for a hard coat layer containing inorganic oxide fine particles having an insulating property. It is. The pressure-sensitive adhesive sheet 1 for a battery having the hard coat layer 12 and satisfying at least one of the conditions 1 and 2 described above has an insulating property even when heated at a high temperature even under normal conditions as described above. Excellent.

  The hard coat layer 12 is preferably cured by irradiation with active energy rays. Therefore, it is preferable that the composition for hard-coat layers for forming the hard-coat layer 12 contains an active energy ray curable component and the said inorganic oxide fine particle.

(1-1) Active Energy Ray-Curable Component The active energy ray-curable component is not particularly limited as long as it can be cured by irradiation with active energy rays to exhibit a desired hardness.

  Specific examples of the active energy ray-curable component include polyfunctional (meth) acrylate monomers, (meth) acrylate prepolymers, etc. Among them, polyfunctional (meth) acrylate monomers and / or (meth It is preferable that it is an acrylate-type prepolymer. The polyfunctional (meth) acrylate monomer and the (meth) acrylate prepolymer may be used alone or in combination. In the present specification, (meth) acrylate means both acrylate and methacrylate. Other similar terms are also the same.

  As a polyfunctional (meth) acrylate monomer, for example, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, polyethylene glycol di (Meth) acrylate, hydroxypivalate neopentyl glycol di (meth) acrylate, dicyclopentanyl di (meth) acrylate, caprolactone modified dicyclopentenyl di (meth) acrylate, ethylene oxide modified phosphate di (meth) acrylate, allylated Cyclohexyl di (meth) acrylate, isocyanurate di (meth) acrylate, trimethylolpropane tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, propionic acid modified dipenta Lysitol tri (meth) acrylate, pentaerythritol tri (meth) acrylate, propylene oxide modified trimethylolpropane tri (meth) acrylate, tris (acryloxyethyl) isocyanurate, propionic acid modified dipentaerythritol penta (meth) acrylate, di Polyfunctional (meth) acrylates such as pentaerythritol hexa (meth) acrylate and caprolactone modified dipentaerythritol hexa (meth) acrylate can be mentioned. One of these may be used alone, or two or more of these may be used in combination. The polyfunctional (meth) acrylate monomer is not particularly limited, but from the viewpoint of preventing the metal oxide particles from coming out of the hard coat layer 12 while immersed in the electrolytic solution, the one having a molecular weight of less than 1000 is more preferable preferable.

  On the other hand, as a (meth) acrylate type prepolymer, prepolymers, such as polyester acrylate type, epoxy acrylate type, urethane acrylate type, a polyol acrylate type, are mentioned, for example. The prepolymers may be used alone or in combination of two or more.

  It is preferable that the glass transition point after hardening of the active energy ray curable component which comprises the hard-coat layer 12 of this embodiment is 130 degreeC or more, It is more preferable that it is 150 degreeC or more, A glass transition point is observed It is particularly preferred that the When the glass transition point of the active energy ray curable component is as described above, the heat resistance of the hard coat layer 12 becomes excellent, and the battery pressure-sensitive adhesive sheet 1 provided with such a hard coat layer 12 is included. Battery performance and safety will also be excellent.

  In addition, when using 2 or more types of active energy ray curable components in the hard-coat layer 12 of this embodiment, it is preferable that those active energy ray curable components are mutually excellent in compatibility.

(1-2) Inorganic Oxide Fine Particles The inorganic oxide fine particles used in the present embodiment are insulating inorganic oxide fine particles. Examples of the inorganic oxide fine particles include fine particles made of materials such as aluminum, zirconium, magnesium, titanium, hafnium, yttrium, germanium, zinc, copper, tungsten sol, oxides of metals such as cobalt and tin, silica and the like. Be One of these may be used alone, or two or more may be used in combination. In particular, metal oxide fine particles are more preferable because they have low decomposition solubility to hydrofluoric acid generated when a salt such as lithium hexafluorophosphate which is an electrolyte in an electrolytic solution reacts with water. That is, if it is metal oxide fine particles, even if the pressure-sensitive adhesive sheet 1 for a battery is immersed in the electrolyte solution of the battery for a long time, it is difficult for the hard coat layer 12 to slip out. Therefore, the adhesive sheet 1 for batteries provided with the hard-coat layer 12 containing metal oxide fine particles becomes the thing excellent in insulation, even when it is immersed in electrolyte solution for a long time, and it is made to heat at high temperature after that.

  The inorganic oxide fine particles are preferably contained in the composition for hard coat layer as a sol of inorganic oxide. By forming the hard coat layer 12 using the composition for a hard coat layer containing such an inorganic oxide sol, the degree of dispersion of the inorganic oxide fine particles contained in the hard coat layer 12 is compared It is easy to adjust to As a result, the haze value of the hard coat layer 12 becomes relatively high, and the battery pressure-sensitive adhesive sheet 1 easily meets at least one of the conditions 1 and 2 described above. As a result, the battery pressure-sensitive adhesive sheet 1 can easily achieve excellent insulation.

  Preferred examples of the inorganic oxide sol include metal oxide sols and silica sols containing the above-mentioned metals as constituent elements, and metal oxide sols are particularly preferable from the viewpoint of easily achieving excellent insulation. .

  Specific examples of metal oxide sols include alumina sol, zirconia sol, magnesia sol, titania sol, barium titanate sol, hafnia sol, yttria sol, germania sol, zinc oxide sol, copper oxide sol, tungsten oxide sol, cobalt oxide sol, cobalt oxide sol, oxide Tin sol etc. are mentioned. Among them, alumina sols, zirconia sols and magnesia sols are particularly preferable, which are excellent in insulation and difficult to slip out of the hard coat layer 12 even when immersed in an electrolytic solution for a long time. Furthermore, alumina sols and alumina sols are more preferable. Zirconia sol is preferred. One of these may be used alone, or two or more of these may be used in combination.

  The dispersion medium of the metal oxide sol is preferably propylene glycol monomethyl ether, methyl isobutyl ketone, ethyl acetate or toluene from the viewpoint of compatibility with the active energy ray-curable component. The concentration of metal oxide particles in the metal oxide sol is preferably 10% by mass or more, particularly preferably 12% by mass or more, and further preferably 15% by mass or more. The concentration is preferably 50% by mass or less, particularly preferably 40% by mass or less, and further preferably 30% by mass or less.

  The inorganic oxide fine particles may be surface-modified by an organic compound. As the said organic compound, what has unsaturated hydrocarbon groups, such as a (meth) acryloyl group and a vinyl group, is mentioned. The inorganic oxide fine particles which have been surface-modified with such an organic compound to have an unsaturated hydrocarbon group on the surface can form a bond with the above-mentioned active energy ray-curable component Become. Thereby, the detachment of the inorganic oxide fine particles from the hard coat layer 12 into the electrolytic solution is effectively suppressed.

  The average particle diameter of the inorganic oxide fine particles is preferably 1 nm or more, particularly preferably 5 nm or more, and further preferably 10 nm or more. The average particle diameter of the inorganic oxide fine particles is preferably 1000 nm or less, particularly preferably 750 nm or less, and further preferably 500 nm or less. When the average particle diameter of the inorganic oxide fine particles is 1 nm or more, the haze value of the hard coat layer 12 can be easily improved, and the hard coat layer 12 satisfying the condition 1 described above can be easily obtained. In addition, when the hard coat layer 12 is formed on the substrate 11 because the average particle diameter of the inorganic oxide fine particles is 1000 nm or less, unevenness of the surface of the hard coat layer 12 on the opposite side to the substrate 11 The occurrence can be effectively prevented. Furthermore, by forming the pressure-sensitive adhesive layer 13 on the surface, it is possible to obtain very high smoothness on the surface of the pressure-sensitive adhesive layer 13 opposite to the hard coat layer 12. Thus, the pressure-sensitive adhesive layer 13 can exhibit excellent adhesion to the adherend. In addition, the average particle diameter of inorganic oxide fine particles shall be measured by the laser diffraction scattering type particle size distribution measuring apparatus.

  The content of the inorganic oxide fine particles in the composition for a hard coat layer is preferably 1 part by volume or more, more preferably 5 parts by volume or more with respect to 100 parts by volume of the active energy ray-curable component. In particular, it is preferably 10 parts by volume or more, and more preferably 30 parts by volume or more. In addition, the content is preferably 500 parts by volume or less, particularly preferably 200 parts by volume or less, and further preferably 100 parts by volume or less. When the content of the inorganic oxide fine particles in the composition for the hard coat layer is in the above range, the insulating property, in particular, the insulation at the time of high temperature heating after long-term immersion of the electrolytic solution while maintaining the strength of the hard coat layer 12 The sex can be made better.

The content of the inorganic oxide fine particles in the hard coat layer 12 is preferably 0.05 cm ³ / ^{m 2} or more, preferably particularly 0.2 cm ³ / ^{m 2} or more, further 0. It is preferable that it is 3 cm < ³ > / m < ² > or more. Further, the content, ^{7 cm} 3 / ^m is preferably ² or less, more preferably ^{5 cm} 3 / ^{m 2} or less, preferably especially ^{3 cm} 3 / ^{m 2} or less, more ^{1 cm} 3 / m is preferably ² or less. When the content of the inorganic oxide fine particles in the hard coat layer 12 is in the above range, the insulation property, in particular, the insulation property at the time of high temperature heating after long-term immersion in the electrolytic solution is maintained while maintaining the strength of the hard coat layer 12 It can be better.

(1-3) Other Components The composition for forming the hard coat layer 12 of the present embodiment may contain various additives in addition to the components described above. As various additives, for example, a photopolymerization initiator, an antioxidant, an antistatic agent, a silane coupling agent, an antiaging agent, a thermal polymerization inhibitor, a colorant, a surfactant, a storage stabilizer, a plasticizer, and a lubricant , Antifoam agents, organic fillers and the like.

  In the case of forming the hard coat layer 12 using ultraviolet light as active energy rays, it is preferable to use a photopolymerization initiator. The photopolymerization initiator is not particularly limited as long as it functions as a photopolymerization initiator of the active energy ray-curable component to be used, but, for example, acyl phosphine oxide compounds, benzoin compounds, acetophenone compounds, titanocene compounds, thioxanthone Compounds, peroxide compounds and the like can be mentioned. Specifically, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 2,2-dimethoxy-1,2-diphenylethane-1-one, benzoin, benzoin Examples include methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyl diphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, dibenzyl, diacetyl, β-chloro anthraquinone and the like. One of these may be used alone, or two or more of these may be used in combination.

  In general, the content of the photopolymerization initiator in the composition for hard coat layer is preferably 0.1 parts by mass or more, and particularly preferably 1 part by mass, with respect to 100 parts by mass of the active energy ray-curable component. It is preferable that it is more than. In addition, the content is preferably 20 parts by mass or less, and particularly preferably 15 parts by mass or less.

(2) Physical Properties of Hard Coat Layer In the pressure-sensitive adhesive sheet 1 for a battery according to the present embodiment, the hard coat layer 12 in the state provided on the substrate 11 is a load of 100 g / cm ² using # 0000 steel wool. It is preferable that the hard coat layer 12 be rubbed back and forth 10 cm for 10 cycles so that no scratch occurs. With such steel wool resistance evaluation, the permeation of the hard coat layer 12 of the electrolytic solution is effectively blocked, and the detachment of the inorganic oxide fine particles due to the swelling of the hard coat layer 12 is effectively suppressed.

1-3. Pressure-Sensitive Adhesive Layer The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer 13 is not particularly limited, and can be appropriately selected from the viewpoints of elution to an electrolytic solution, flame retardancy, heat resistance, insulation and the like. Especially as an adhesive which comprises the adhesive layer 13, an acrylic adhesive, a silicone adhesive, a rubber adhesive, and a urethane adhesive are preferable. Among them, acrylic pressure-sensitive adhesives are particularly preferable from the viewpoints of adhesion to the hard coat layer 12 and electrodes, easiness of fine adjustment of adhesion, and the like.

  It is preferable that an acrylic adhesive is obtained from the adhesive composition (Hereafter, it may be called "adhesive composition P.") containing a (meth) acrylic acid ester polymer (A). The adhesive composition P preferably contains a crosslinking agent (B) in addition to the (meth) acrylic acid ester polymer (A), and particularly preferably contains a silane coupling agent (C). In addition, in this specification, the concept of a "copolymer" shall also be included in a "polymer."

(1) Each component (1-1) (meth) acrylic acid ester polymer (A)
The (meth) acrylic acid ester polymer (A) has a preferable adhesiveness by containing a (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms of an alkyl group as a monomer unit constituting the polymer. It can be expressed. Examples of the (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate and n- (meth) acrylate Butyl, n-pentyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, n-decyl (meth) acrylate, (meth) acrylate n-dodecyl, myristyl (meth) acrylate, palmityl (meth) acrylate, stearyl (meth) acrylate and the like can be mentioned. Among them, from the viewpoint of further improving the adhesiveness, it is preferable that the (meth) acrylic acid ester having 1 to 8 carbon atoms in the alkyl group is contained. These may be used alone or in combination of two or more.

  The (meth) acrylic acid ester polymer (A) preferably contains 50% by mass or more of (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group as a monomer unit constituting the polymer. In particular, the content is preferably 60% by mass or more, and more preferably 70% by mass or more. When 50 mass% or more of the (meth) acrylic acid alkyl ester is contained, the (meth) acrylic acid ester polymer (A) can exhibit suitable adhesiveness. In addition, the (meth) acrylic acid ester polymer (A) contains, as a monomer unit constituting the polymer, 99 mass% or less of (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms of an alkyl group. In particular, the content is preferably 97% by mass or less, and more preferably 90% by mass or less. By adjusting the (meth) acrylic acid alkyl ester to 99% by mass or less, other monomer components can be introduced into the (meth) acrylic acid ester polymer (A) in a suitable amount.

  Moreover, the (meth) acrylic acid ester polymer (A) is a glass transition as a homopolymer, as a (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms of an alkyl group as a monomer unit constituting the polymer. It is also preferable to use a combination of a monomer (hard monomer) whose temperature (Tg) exceeds 0 ° C. and a monomer (soft monomer) whose glass transition temperature (Tg) as a homopolymer is 0 ° C. or less. Thereby, the elution resistance to the electrolytic solution can be further improved. In this case, the weight ratio of the hard monomer to the soft monomer is preferably 5:95 to 40:60, and more preferably 20:80 to 30:70.

  Examples of the hard monomer include methyl acrylate (Tg 10 ° C.), methyl methacrylate (Tg 105 ° C.), isobornyl acrylate (Tg 94 ° C.), isobornyl methacrylate (Tg 180 ° C.), adamantyl acrylate (Tg 115 ° C.), methacrylic acid Examples include adamantyl (Tg 141 ° C.) and the like. These may be used alone or in combination of two or more.

  Among the above hard monomers, methyl acrylate, methyl methacrylate and isobornyl acrylate are preferable from the viewpoint of exerting the performance of the hard monomer while preventing adverse effects on the properties such as adhesiveness, and in particular methyl acrylate and methacrylic acid. Methyl is preferred.

  As said soft monomer, the acrylic acid alkylester which has a C2-C12 linear or branched alkyl group is mentioned preferably. For example, 2-ethylhexyl acrylate (Tg-70 ° C), n-butyl acrylate (Tg-54 ° C) and the like are preferable, and n-butyl acrylate is particularly preferable. These may be used alone or in combination of two or more.

  The (meth) acrylic acid ester polymer (A) may optionally contain other monomers as monomer units constituting the polymer. The other monomer may be a monomer containing a functional group having reactivity, or may be a monomer not containing a functional group having reactivity.

  As a monomer containing a functional group having reactivity (reactive functional group-containing monomer), a monomer having a carboxy group in the molecule (carboxy group-containing monomer), a monomer having a hydroxyl group in the molecule (hydroxyl-containing monomer), an intramolecular And monomers having an amino group (amino group-containing monomers) and the like. Among these, the (meth) acrylic acid ester polymer (A) preferably contains, as a monomer unit constituting the polymer, a carboxy group-containing monomer. When a metal chelate-based crosslinking agent is used as the crosslinking agent (B) described later, the carboxy group derived from the carboxy group-containing monomer reacts with the metal chelate-based crosslinking agent at the time of crosslinking of the (meth) acrylic acid ester polymer (A) To form a cross-linked structure which is a three-dimensional network structure. The pressure-sensitive adhesive having a crosslinked structure by the reaction of the carboxy group with the metal chelate-based crosslinking agent has high resistance to an electrolytic solution, particularly a non-aqueous electrolytic solution, and is hardly eluted even when in contact with the electrolytic solution.

  Examples of carboxy group-containing monomers include ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, citraconic acid and the like. Among these, acrylic acid is preferred. According to acrylic acid, the above effects become more excellent. The carboxy group-containing monomers may be used alone or in combination of two or more.

  The (meth) acrylic acid ester polymer (A) preferably contains, as a lower limit value, 0.5% by mass or more of a carboxy group-containing monomer as a monomer unit constituting the polymer, particularly 1% by mass or more Preferably, the content is 3% by mass or more. In addition, the (meth) acrylic acid ester polymer (A) preferably contains a carboxy group-containing monomer as an upper limit value of 30% by mass or less, particularly 25% by mass or less, as a monomer unit constituting the polymer. Preferably, the content is 20% by mass or less. When the (meth) acrylic acid ester polymer (A) contains a carboxy group-containing monomer in the above amount as a monomer unit, the above-mentioned effects become more excellent in the obtained adhesive.

  Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, (meth And (iii) hydroxyalkyl esters of (meth) acrylic acid such as 3-hydroxybutyl acrylate and 4-hydroxybutyl (meth) acrylate. These may be used alone or in combination of two or more.

  Examples of the amino group-containing monomer include aminoethyl (meth) acrylate and n-butylaminoethyl (meth) acrylate. These may be used alone or in combination of two or more.

  The reactive functional group-containing monomer is preferably only the above-mentioned carboxy group-containing monomer, in order not to inhibit the effect obtained by the cross-linked structure by the reaction of the carboxy group and the metal chelate-based crosslinking agent.

  On the other hand, examples of the monomer not containing a reactive functional group include (meth) acrylic acid alkoxyalkyl esters such as methoxyethyl (meth) acrylate and ethoxyethyl (meth) acrylate, (meth) acrylic acid N, (Meth) acrylic acid ester having non-crosslinkable tertiary amino group such as N-dimethylaminoethyl, N, N-dimethylaminopropyl (meth) acrylate and (meth) acryloyl morpholine, (meth) acrylamide, dimethyl acrylamide , Vinyl acetate, styrene and the like. These may be used alone or in combination of two or more.

  The polymerization mode of the (meth) acrylic acid ester polymer (A) may be a random copolymer or a block copolymer.

  The lower limit of the weight average molecular weight of the (meth) acrylic acid ester polymer (A) is preferably 50,000 or more, more preferably 100,000 or more, and particularly preferably 200,000 or more. Is preferably 500,000 or more. When the lower limit value of the weight average molecular weight of the (meth) acrylic acid ester polymer (A) is above, the elution resistance of the obtained pressure-sensitive adhesive to the electrolytic solution becomes more excellent.

  Further, the weight average molecular weight of the (meth) acrylic acid ester polymer (A) is preferably not more than 2,500,000 as an upper limit value, more preferably not more than 2,000,000, and particularly preferably not more than 1,500,000. Furthermore, it is preferable that it is 1.2 million or less. When the upper limit value of the weight average molecular weight of the (meth) acrylic acid ester polymer (A) is above, the adhesive strength of the obtained pressure-sensitive adhesive becomes more excellent. In addition, the weight average molecular weight in this specification is the value of standard polystyrene conversion measured by the gel permeation chromatography (GPC) method.

  In addition, in the adhesive composition P, a (meth) acrylic acid ester polymer (A) may be used individually by 1 type, and may be used in combination of 2 or more type.

(1-2) Crosslinking agent (B)
The crosslinking agent (B) may be any one that reacts with the reactive functional group possessed by the (meth) acrylic acid ester polymer (A). For example, an isocyanate crosslinking agent, an epoxy crosslinking agent, an amine crosslinking agent Melamine based crosslinking agent, Aziridine based crosslinking agent, Hydrazine based crosslinking agent, Aldehyde based crosslinking agent, Alkaline based crosslinking agent, Metal alkoxide based crosslinking agent, Metal chelate based crosslinking agent, Metal salt based crosslinking agent, Ammonium salt based crosslinking agent, etc. Can be mentioned. As the crosslinking agent (B), one type may be used alone, or two or more types may be used in combination.

  Among the above, it is preferable to use a metal chelate-based crosslinking agent as the crosslinking agent (B). In this case, the (meth) acrylic acid ester polymer (A) preferably contains a carboxy group-containing monomer as a monomer unit constituting the polymer. By this combination, as described above, the obtained pressure-sensitive adhesive has high resistance to the electrolyte solution, particularly the non-aqueous electrolyte solution, and is hardly eluted even when in contact with the electrolyte solution. Therefore, the adhesive does not adversely affect the battery performance, and the malfunction of the battery due to the adhesive elution is suppressed.

  As a metal chelate type crosslinking agent, a metal chelate compound whose metal atom is aluminum, zirconium, titanium, zinc, iron, tin or the like can be used. Among them, aluminum chelate compounds are particularly preferable. The aluminum chelate compound particularly effectively exerts the above-mentioned elution resistance to the electrolytic solution.

  As an aluminum chelate compound, for example, diisopropoxyaluminum monooleyl acetoacetate, monoisopropoxyaluminum bisoleyl acetoacetate, monoisopropoxyaluminum monooleate monoethyl acetoacetate, diisopropoxyaluminum monolauryl acetoacetate, diisopropoxyaluminum Aluminum monostearylacetoacetate, diisopropoxyaluminum monoisostearylacetoacetate, monoisopropoxyaluminum mono-N-lauroyl-β-alanate monolaurylacetoacetate, aluminum tris (acetylacetonate), monoacetylacetonate aluminum bis ( Isobutyl acetoacetate) chelate, monoacetylacetonate aluminum Umubisu (2-ethylhexyl acetoacetate) chelate, monoacetylacetonate aluminum bis (dodecyl acetoacetate) chelate, monoacetylacetonate aluminum bis (oleyl acetoacetate) chelate, and the like. Among these, aluminum tris (acetylacetonate) is preferable from the viewpoint of the above effect. These may be used alone or in combination of two or more.

  Moreover, as other metal chelate compounds, for example, titanium tetrapropionate, titanium tetra-n-butylate, titanium tetra-2-ethylhexanoate, zirconium sec-butylate, zirconium diethoxy-tert-butyrate, triethanol Amine titanium dipropionate, ammonium salt of titanium lactate, tetraoctylene glycol titanate and the like can be mentioned. These may be used alone or in combination of two or more.

  The above-mentioned metal chelate-based crosslinking agents may be used alone or in combination of two or more.

  Content of the metal chelate type crosslinking agent (B) in adhesive composition P which concerns on this embodiment is 0.1 mass as a lower limit with respect to 100 mass parts of (meth) acrylic acid ester polymers (A). The content is preferably at least parts, more preferably at least 0.2 parts by mass, particularly preferably at least 0.3 parts by mass, and still more preferably at least 0.5 parts by mass. In addition, the content of the metal chelate crosslinking agent (B) is preferably 5 parts by mass or less as the upper limit value, particularly preferably 4 parts by mass or less, and further preferably 3 parts by mass or less . When the content of the metal chelate crosslinking agent (B) is in the above range, the above-described effects become more excellent.

  Moreover, adhesive composition P which concerns on this embodiment may contain crosslinking agents other than a metal chelate type crosslinking agent (B). As a crosslinking agent other than metal chelate type crosslinking agent (B), for example, isocyanate type crosslinking agent, epoxy type crosslinking agent, amine type crosslinking agent, melamine type crosslinking agent, aziridine type crosslinking agent, hydrazine type crosslinking agent, aldehyde type crosslinking Agents, oxazoline based crosslinking agents, metal alkoxide based crosslinking agents, metal salt based crosslinking agents, ammonium salt based crosslinking agents and the like. Among the above, preferred is an isocyanate-based crosslinking agent which reacts with a carboxy group without inhibiting the reaction of the carboxy group of the (meth) acrylic acid ester polymer (A) with the metal chelate-based crosslinking agent (B).

  The isocyanate crosslinking agent contains at least a polyisocyanate compound. Examples of polyisocyanate compounds include aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, aliphatic polyisocyanates such as hexamethylene diisocyanate, alicyclic polyisocyanates such as isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, and the like And biuret bodies thereof, isocyanurate bodies, and adducts which are reaction products with low molecular weight active hydrogen-containing compounds such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, castor oil and the like. Among them, from the viewpoint of reactivity with a hydroxyl group, trimethylolpropane-modified aromatic polyisocyanates, particularly, trimethylolpropane-modified tolylene diisocyanate and trimethylolpropane-modified xylylene diisocyanate are preferable, and further, trimethylolpropane-modified tolylene diisocyanate is preferable. . These may be used alone or in combination of two or more.

  When an isocyanate crosslinking agent is used in combination, the mass ratio of the metal chelate crosslinking agent (B) to the isocyanate crosslinking agent is preferably 99: 1 to 1:99, particularly 90:10 to 5:95. Is preferably 20:80 to 10:90.

(1-3) Silane coupling agent (C)
The adhesive composition P preferably contains a silane coupling agent (C). When the silane coupling agent (C) is contained, even when the pressure-sensitive adhesive layer 13 is in contact with the electrolytic solution, it exhibits excellent adhesion to an adherend (particularly to a metal member). As a result, peeling of the battery adhesive sheet 1 from the adherend is further suppressed, and a decrease in battery performance caused by the battery adhesive sheet 1 is suppressed. Moreover, the adhesive layer 13 obtained becomes a thing with the adhesiveness with respect to the hard-coat layer 12 higher. Therefore, it is prevented that peeling etc. occur at the interface between the hard coat layer 12 and the adhesive layer 13 by immersing the adhesive sheet 1 for battery in the electrolyte solvent, and the adhesion after immersion in the electrolyte solvent is made high. be able to. Furthermore, when peeling the release sheet 14 from the pressure-sensitive adhesive layer 13, it can be effectively suppressed that the pressure-sensitive adhesive layer 13 is transferred to the release sheet 14 and peeled from the hard coat layer 12.

  The silane coupling agent (C) is preferably an organosilicon compound having at least one alkoxysilyl group in the molecule and having good compatibility with the (meth) acrylic acid ester polymer (A).

  As such a silane coupling agent (C), for example, polymerizable unsaturated group-containing silicon compounds such as vinyltrimethoxysilane, vinyltriethoxysilane, methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, Silicon compounds having an epoxy structure such as 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, mercapto groups such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyldimethoxymethylsilane Amino group-containing silicon compounds such as 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, etc. Silicon compounds, 3-chloropropyltrimethoxysilane, 3-isocyanatepropyltriethoxysilane, or at least one of these, and alkyltril groups such as methyltriethoxysilane, ethyltriethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, etc. A condensate with a silicon compound etc. are mentioned. Among these, in view of the above effects, silicon compounds having an epoxy structure are preferable, and 3-glycidoxypropyltrimethoxysilane is particularly preferable. One of these may be used alone, or two or more of these may be used in combination.

  The content of the silane coupling agent (C) in the adhesive composition P is preferably 0.01 parts by mass or more with respect to 100 parts by mass of the (meth) acrylic acid ester polymer (A), and 0 The content is more preferably 0.05 parts by mass or more, particularly preferably 0.1 parts by mass or more, and further preferably 0.4 parts by mass or more. In addition, the content is preferably 5 parts by mass or less, more preferably 4 parts by mass or less, particularly preferably 3 parts by mass or less, and further preferably 1.5 parts by mass or less Is preferred. When the content of the silane coupling agent (C) is in the above range, the adhesion after immersion in a solvent of an electrolytic solution is more excellent.

(1-4) Various Additives In the adhesive composition P, various additives generally used for acrylic pressure-sensitive adhesives, for example, tackifiers, antioxidants, softeners, fillers, etc., are optionally added. can do. In addition, the below-mentioned polymerization solvent and dilution solvent shall not be contained in the additive which comprises the adhesive composition P.

(2) Production of adhesive composition The adhesive composition P produces a (meth) acrylic acid ester polymer (A), and the obtained (meth) acrylic acid ester polymer (A) optionally produces It can manufacture by adding a crosslinking agent (B), a silane coupling agent (C), an additive, etc.

  The (meth) acrylic acid ester polymer (A) can be produced by polymerizing a mixture of monomers constituting the polymer by a conventional radical polymerization method. The polymerization of the (meth) acrylic acid ester polymer (A) can be carried out by solution polymerization or the like, using a polymerization initiator, if desired. As a polymerization solvent, ethyl acetate, n-butyl acetate, isobutyl acetate, toluene, acetone, hexane, methyl ethyl ketone etc. are mentioned, for example, You may use 2 or more types together.

  As a polymerization initiator, an azo compound, an organic peroxide, etc. are mentioned, You may use 2 or more types together. As an azo compound, for example, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-methylbutyronitrile), 1,1′-azobis (cyclohexane 1-carbonitrile), 2 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (2,4-dimethyl-4-methoxyvaleronitrile), dimethyl 2,2'-azobis (2-methyl propionate) 4,4'-azobis (4-cyanovaleric acid), 2,2'-azobis (2-hydroxymethylpropionitrile), 2,2'-azobis [2- (2-imidazolin-2-yl) Propane] and the like.

  As the organic peroxide, for example, benzoyl peroxide, t-butyl perbenzoate, cumene hydroperoxide, diisopropyl peroxy dicarbonate, di-n-propyl peroxy dicarbonate, di (2-ethoxyethyl) peroxy Dicarbonate, t-butyl peroxy neodecanoate, t-butyl peroxy bivalate, (3,5,5-trimethylhexanoyl) peroxide, dipropionyl peroxide, diacetyl peroxide and the like can be mentioned.

  In addition, in the said superposition | polymerization process, the weight average molecular weight of the polymer obtained can be adjusted by mix | blending chain transfer agents, such as 2-mercapto ethanol.

  When the (meth) acrylic acid ester polymer (A) is obtained, optionally, a crosslinking agent (B), a silane coupling agent (C), an additive, and a solution of the (meth) acrylic acid ester polymer (A) The adhesive composition P is obtained by adding etc. and thoroughly mixing.

  In addition, in order to adjust the adhesive composition P to a viscosity suitable for coating or to adjust the pressure-sensitive adhesive layer to a desired film thickness, appropriately add it to the above-mentioned polymerization solvent and dilute it with a dilution solvent, etc. It may be a coating solution described later. Examples of the dilution solvent include ethyl acetate, n-butyl acetate, isobutyl acetate, toluene, acetone, hexane, methyl ethyl ketone and the like, and two or more kinds may be used in combination.

(3) Physical Properties of Pressure-Sensitive Adhesive / Pressure-Sensitive Adhesive Layer In the pressure-sensitive adhesive sheet 1 according to the present embodiment, the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer 13 is adhered for 72 hours at 80 ° C. The lower limit of the gel fraction of the agent is preferably 50% or more, more preferably 60% or more, and still more preferably 70% or more. When the lower limit value of the gel fraction is above, the elution amount of the pressure-sensitive adhesive when the pressure-sensitive adhesive layer 13 contacts the electrolytic solution can be suppressed to a low level. As a result, the malfunction of the battery due to the elution of the adhesive is more effectively suppressed.

  On the other hand, the upper limit value of the gel fraction is preferably 100% or less, particularly preferably 99% or less, and further preferably 98% or less. When the upper limit of the gel fraction is 98% or less, the battery pressure-sensitive adhesive sheet 1 has appropriate flexibility, and the battery has a level difference as in the case of fixing the electrode and the electrode extraction tab. Even when the pressure-sensitive adhesive sheet 1 is attached, the step can be favorably followed.

  In addition, the solvent of the non-aqueous electrolyte solution here is a preparation liquid which mixed ethylene carbonate and diethyl carbonate by volume ratio of 1: 1, and the test method of a gel fraction can be measured as follows. A measurement sheet in which both surfaces of the pressure-sensitive adhesive layer 13 to be measured are protected by a release sheet is prepared. The measurement sheet is cut into a size of 80 mm × 80 mm, and the release sheet protecting both surfaces of the pressure-sensitive adhesive layer 13 is peeled off. The pressure-sensitive adhesive layer 13 thus obtained is wrapped in a polyester mesh (mesh size 200), the mass thereof is weighed with a precision balance, and the mass of the adhesive alone is calculated by subtracting the mass of the mesh alone. The mass at this time is M1. Next, the adhesive wrapped in the polyester mesh is immersed in a preparation solution in which ethylene carbonate and diethyl carbonate are mixed at a volume ratio of 1: 1 as an electrolyte solvent at 80 ° C. for 72 hours. Thereafter, the pressure-sensitive adhesive layer is taken out, and once dipped in ethanol, the adhering electrolytic solution solvent is dissolved and removed. Thereafter, it is air-dried for 24 hours in an environment at a temperature of 23 ° C. and a relative humidity of 50%, and further dried in an oven at 80 ° C. for 12 hours. After drying, the mass is weighed with a precision balance, and the mass of the adhesive alone is calculated by subtracting the mass of the mesh alone. The mass at this time is M2. The gel fraction (%) described above can be calculated from the formula of (M2 / M1) × 100 for the values of M1 and M2 obtained as described above.

(4) Thickness of Pressure-Sensitive Adhesive Layer The thickness (value measured according to JIS K 7130) of the pressure-sensitive adhesive layer 13 is preferably 1 μm or more, particularly preferably 3 μm or more, and further preferably 4 μm or more. Is preferred. Further, the thickness is preferably 50 μm or less, particularly preferably 15 μm or less, and further preferably 9 μm or less. By the thickness of the adhesive layer 13 being 1 micrometer or more, the adhesive sheet 1 for batteries can exhibit favorable adhesive force. Moreover, when the thickness of the adhesive layer 13 is 50 micrometers or less, the quantity of the electrolyte solution which infiltrates from the edge part of the adhesive layer 13 can be reduced effectively.

1-4. Release Sheet The release sheet 14 protects the pressure-sensitive adhesive layer until the use of the battery pressure-sensitive adhesive sheet 1 and is peeled off when the battery pressure-sensitive adhesive sheet 1 is used. In the adhesive sheet 1 for batteries which concerns on this embodiment, the peeling sheet 14 is not necessarily required.

  As the release sheet 14, for example, polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polyethylene naphthalate film, polybutylene terephthalate film , Polyurethane film, ethylene vinyl acetate film, ionomer resin film, ethylene (meth) acrylic acid copolymer film, ethylene (meth) acrylic acid ester copolymer film, polystyrene film, polycarbonate film, polyimide film, fluorine resin film And liquid crystal polymer films are used. Moreover, these crosslinked films are also used. Furthermore, these laminated films may be sufficient.

  Peeling treatment is preferably performed on the peeling surface of the peeling sheet 14 (the surface in contact with the pressure-sensitive adhesive layer 13). Examples of the release agent used for the release treatment include alkyd-based, silicone-based, fluorine-based, unsaturated polyester-based, polyolefin-based and wax-based release agents.

  The thickness of the release sheet 14 is not particularly limited, but is usually about 20 to 150 μm.

2. Physical Properties of Adhesive Sheet for Battery, Etc. The adhesive strength to the aluminum plate of the adhesive sheet 1 for a battery according to the present embodiment is preferably 0.5 N / 25 mm or more as a lower limit, and particularly preferably 0.75 N / 25 mm or more Is more preferable, and 1.0 N / 25 mm or more is more preferable. Since the lower limit value of the adhesive force before the electrolyte solution solvent immersion of the adhesive sheet 1 for batteries is above, the adhesive sheet 1 for batteries is an adherend (especially metal) before the adhesive sheet 1 for battery contacts the electrolyte. It is difficult for the problem of peeling off from the member) to occur. The upper limit of the adhesive strength before immersion in the electrolytic solution solvent is not particularly limited, but usually it is preferably 50 N / 25 mm or less, particularly preferably 40 N / 25 mm or less, and further preferably 30 N / 25 mm or less Is preferred.

  In addition, the adhesive force in this specification says the adhesive force measured by the 180 degree peeling method basically based on JISZ0237: 2009, and can be measured as follows. The battery adhesive sheet 1 is cut into a width of 25 mm and a length of 250 mm, and then the release sheet 14 is peeled off to obtain a test piece. The exposed adhesive layer 13 of the test piece is attached to an aluminum plate as an adherend using a 2 kg rubber roller under an environment of 23 ° C. and 50% RH. Immediately after that, the test piece is peeled off from the above aluminum plate at a peeling angle of 180 ° and a peeling speed of 300 mm / min using a universal tensile tester (trade name “Tensilon UTM-4-100” manufactured by ORIENTEC Co., Ltd.) Thus, the above-mentioned adhesion (N / 25 mm) can be measured.

The resistance value in the thickness direction at normal time (normal temperature, normal humidity, normal pressure) of the battery pressure-sensitive adhesive sheet 1 (excluding the release sheet 14) is preferably 1.0 × 10 ¹⁰ Ω or more. It can be said that the said battery adhesive sheet 1 is excellent in insulation because the resistance value of the thickness direction of the battery adhesive sheet 1 is more than the above, and the battery using the said battery adhesive sheet 1 The occurrence of short circuit and thermal runaway is suppressed. The upper limit value of the resistance value is not particularly limited, but in general, it is preferably 1.0 × 10 ¹⁶ Ω or less.

  Here, the resistance value in the thickness direction of the pressure-sensitive adhesive sheet for battery in the present specification is located on the pressure-sensitive adhesive sheet for battery and the back surface located on the surface of a laminate obtained by sticking the pressure-sensitive adhesive sheet for battery on a 1 mm thick aluminum plate. It measures by making the terminal of a tester contact each of an aluminum board. Details are as shown in the test described later.

Moreover, the resistance value of the thickness direction of the said adhesive sheet 1 (except peeling sheet 14) for the said battery after heating the adhesive sheet 1 for batteries in nitrogen atmosphere of 80 degreeC for 1 hour is 1.0 * 10 < ¹⁰ > ohm. It is preferable that it is more than. By the said resistance value being the above or more, it can be said that the battery adhesive sheet 1 is excellent in insulation, even when heated at high temperature.

Furthermore, the resistance value in the thickness direction of the pressure-sensitive adhesive sheet 1 (except for the release sheet 14) after the battery pressure-sensitive adhesive sheet 1 is immersed in a non-aqueous electrolyte and heated at 80 ° C. for 4 weeks is 1.0. It is preferable that it is 10 ¹⁰ Ω or more. When the said resistance value is the above or more, it can be said that the adhesive sheet 1 for batteries is excellent in insulation, even when it is a case where it is immersed in electrolyte solution for a long time. In addition, the non-aqueous electrolyte solution here is prepared by dissolving lithium hexafluorophosphate (LiPF ₆ ) at a concentration of 1 mol / L in a mixed solution in which ethylene carbonate and diethyl carbonate are mixed at a volume ratio of 1: 1. It is a liquid.

  The thickness of the pressure-sensitive adhesive sheet 1 for batteries (excluding the thickness of the release sheet 14) is preferably 10 μm or more, particularly preferably 15 μm or more, and further preferably 20 μm or more. Further, the thickness is preferably 250 μm or less, particularly preferably 110 μm or less, and further preferably 45 μm or less. When the thickness of the battery pressure-sensitive adhesive sheet 1 is in the above range, the battery pressure-sensitive adhesive sheet 1 is more suitable in which the adhesive strength and the insulation property are compatible.

3. Manufacturing method of adhesive sheet for batteries The adhesive sheet 1 for batteries which concerns on this embodiment produces the laminated body of the base material 11 and the hard-coat layer 12, and the laminated body of the adhesive layer 13 and the peeling sheet 14, respectively, for example It can manufacture by pasting these laminated bodies so that hard coat layer 12 and adhesive layer 13 may contact. From the viewpoint of improving the adhesion between the hard coat layer 12 and the pressure-sensitive adhesive layer 13, corona treatment, plasma treatment, etc. on the surface to which one of these layers is to be bonded or the surface to which both layers are to be bonded. It is also preferable to bond the two layers after performing the surface treatment.

  The laminate of the substrate 11 and the hard coat layer 12 can be produced, for example, as follows. First, a coating solution containing a composition for a hard coat layer and, optionally, a solvent, is applied to one of the main surfaces of the substrate 11 and dried. The coating solution may be applied by a conventional method, for example, by a bar coating method, a knife coating method, a Mayer bar method, a roll coating method, a blade coating method, a die coating method, or a gravure coating method. Drying can be performed, for example, by heating at 80 to 150 ° C. for about 30 seconds to 5 minutes.

Thereafter, the layer obtained by drying the coating solution is irradiated with active energy rays to cure the layer and form the hard coat layer 12. As an active energy ray, what has an energy quantum can be used among electromagnetic waves or a charged particle beam, for example, and an ultraviolet ray, an electron beam, etc. can be used specifically ,. In particular, ultraviolet light which is easy to handle is preferable. The irradiation of the ultraviolet light can be performed by a high pressure mercury lamp, a xenon lamp or the like, and the irradiation amount of the ultraviolet light is preferably about 50 to 1000 mW / cm ^{2 of} illuminance. Further, the light quantity is preferably 50~10000mJ / cm ^2, more preferably 80~5000mJ / cm ^2, and particularly preferably 200~2000mJ / cm ^2. On the other hand, the irradiation of the electron beam can be performed by an electron beam accelerator or the like, and the irradiation dose of the electron beam is preferably about 10 to 1000 krad.

  The laminate of the pressure-sensitive adhesive layer 13 and the release sheet 14 can be produced, for example, as follows.

  A coating solution containing the above-mentioned adhesive composition P and optionally a solvent is applied to the release surface of the release sheet 14 and heat treatment is performed to form a coating film. The formed coating film becomes the adhesive layer 13 as it is when the curing period is unnecessary, and becomes the adhesive layer 13 after the aging period when the curing period is necessary.

  The above heat treatment can be combined with the drying treatment at the time of volatilizing the dilution solvent and the like of the coating liquid. When heat-processing, it is preferable that heating temperature is 50-150 degreeC, and it is preferable that it is especially 70-120 degreeC. The heating time is preferably 30 seconds to 10 minutes, and more preferably 50 seconds to 2 minutes. After the heat treatment, if necessary, a curing period of about 1 to 2 weeks may be provided at normal temperature (for example, 23 ° C., 50% RH).

  And the adhesive sheet 1 for batteries is manufactured by laminating | stacking two said laminated bodies so that the adhesive layer 13 and the hard-coat layer 12 may mutually contact | connect. The curing period of the pressure-sensitive adhesive layer 13 may be provided after laminating with the hard coat layer 12.

  As another manufacturing method of the adhesive sheet 1 for batteries which concerns on this embodiment, you may manufacture the adhesive sheet 1 for batteries by forming the hard-coat layer 12 and the adhesive layer 13 in order on the base material 11. FIG.

Lithium-ion battery
The lithium ion battery according to one embodiment of the present invention is fixed inside the battery in a state in which two or more conductors are in contact with each other using the above-described battery pressure-sensitive adhesive sheet. Preferably, at least one of the two or more electrical conductors is in the form of a sheet and at least one is in the form of a line or a tape. Hereinafter, a lithium ion battery according to a preferred embodiment will be described.

  As shown in FIG. 2, in the lithium ion battery 2 according to this embodiment, a bottomed cylindrical exterior body 21 whose bottom portion constitutes a negative electrode terminal 23, and a positive electrode terminal 22 provided in the opening of the exterior body 21. And an electrode body 24 provided inside the exterior body 21. In addition, an electrolytic solution is enclosed in the lithium ion battery 2.

  The electrode body 24 includes a positive electrode current collector 241 on which the positive electrode active material layer 241 a is stacked, a negative electrode current collector 242 on which the negative electrode active material layer 242 a is stacked, and a sheet-like (band-like) And a separator 243. The laminate of the positive electrode current collector 241 and the positive electrode active material layer 241a may be referred to as a positive electrode, and the laminate of the negative electrode current collector 242 and the negative electrode active material layer 242a may be referred to as a negative electrode. Sometimes called an electrode. The positive electrode, the negative electrode, and the separator 243 are respectively wound and inserted into the inside of the exterior body 21.

  Further, as shown in FIG. 3, a linear or tape-like electrode lead-out tab 244 is attached to the positive electrode current collector 241 by the above-described battery adhesive sheet 1, whereby the electrode lead-out tab 244 is It is electrically connected to the positive electrode current collector 241. The electrode extraction tab 244 is also electrically connected to the positive electrode terminal 22. The negative electrode current collector 242 is electrically connected to the negative electrode terminal 23 through an electrode extraction tab (not shown).

  In general, the positive electrode current collector 241 and the negative electrode current collector 242 are made of a metal such as aluminum, and the electrode extraction tab 244 is made of a metal such as aluminum or copper.

The electrolyte used in the lithium ion battery 2 is usually a non-aqueous electrolyte. As this non-aqueous electrolyte solution, for example, one in which a lithium salt as an electrolyte is dissolved in a mixed solvent of a cyclic carbonate and a lower chain carbonate is preferably mentioned. As lithium salts, fluorine-based complex salts such as lithium hexafluorophosphate (LiPF ₆ ) and lithium borofluoride (LiBF ₄ ), LiN (SO ₂ Rf) ₂ · LiC (SO ₂ Rf) ₃ (where Rf = CF ₃ , C ₂ F ₅ ) or the like is used. Moreover, ethylene carbonate, a propylene carbonate, etc. are used as cyclic carbonate ester, Dimethyl carbonate, an ethyl methyl carbonate, a diethyl carbonate etc. are mentioned preferably as a lower chain | strand-shaped carbonate ester.

  The lithium ion battery 2 according to the present embodiment can be manufactured by a usual method except using the above-described battery adhesive sheet 1 for fixing the electrode extraction tab 244.

  In the lithium ion battery 2 according to the present embodiment, the pressure-sensitive adhesive sheet 1 for a battery is used to attach the electrode extraction tab 244 to the positive electrode current collector 241. The pressure-sensitive adhesive sheet 1 for a battery has a hard coat layer 12 obtained by using inorganic oxide fine particles, and at the same time, at least one of the above-described conditions 1 and 2 satisfies high temperature heating even under normal conditions. Even in the case where the substrate 11, the pressure-sensitive adhesive layer 13, the matrix of the hard coat layer 12 and the like are carbonized, the insulating property is excellent.

  From the above, the lithium ion battery 2 according to the present embodiment is a battery having high performance as a battery, in which the performance decrease due to the adhesive sheet, malfunction, thermal runaway and short circuit are suppressed, and the battery is highly reliable. It is expected to be excellent in temperature stability and safety even under conditions of current.

  The embodiments described above are described to facilitate the understanding of the present invention, and are not described to limit the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents that fall within the technical scope of the present invention.

  For example, in the pressure-sensitive adhesive sheet 1 for battery, the release sheet 14 may be omitted. In the battery pressure-sensitive adhesive sheet 1, another layer may be provided between the base 11 and the hard coat layer 12 or between the hard coat layer 12 and the pressure-sensitive adhesive layer 13.

  Hereinafter, the present invention will be more specifically described by way of examples and the like, but the scope of the present invention is not limited to these examples and the like.

Example 1
1. Formation of Hard Coat Layer on Substrate 100 parts by mass of pentaerythritol triacrylate as an active energy ray-curable component (in terms of solid content; the same applies hereinafter) and 3 parts by mass of 1-hydroxycyclohexyl phenyl ketone as a photopolymerization initiator And 195 parts by mass of alumina sol (hereinafter referred to as “alumina sol A”) (in terms of solid content; the same applies hereinafter) as inorganic oxide fine particles, and diluting with ethyl acetate to have a solid content concentration of 16%, A coating solution of the composition for a hard coat layer having a viscosity of 3.35 mPa · s at 23 ° C. was prepared. The volume ratio of the pentaerythritol triacrylate to the alumina sol was 65: 35 (≒ 100: 54).

The above coating solution was applied by Meyer bar to one side of a polyimide film (made by Toray DuPont, trade name "Kapton 100H", thickness: 25 μm, flame resistance level of UL 94 standard: V-0) as a substrate. Thereafter, it was dried at 70 ° C. for 1 minute. Next, the coating film was cured by irradiating the coating film with ultraviolet light (illuminance 230 mW / cm ² , light quantity 510 mJ / cm ² ). As a result, a first laminate was obtained in which a hard coat layer having an inorganic oxide particle content of 0.7 cm ³ / m ² and a thickness of 2.0 μm was formed on one surface of the substrate.

2. Formation of coating film of adhesive composition on release sheet 76.8 parts by mass of butyl acrylate, 19.3 parts by mass of methyl acrylate and 4 parts by mass of acrylic acid are copolymerized by solution polymerization to obtain (meth) acrylic An acid ester polymer was prepared. When the molecular weight of this polymer was measured using gel permeation chromatography (GPC) described later, the weight average molecular weight (Mw) was 1,000,000.

  Next, 100 parts by mass of the obtained (meth) acrylic acid ester polymer, and aluminum tris (acetylacetonate) as a metal chelate-based crosslinking agent (manufactured by Soken Chemical & Co., Ltd., trade name "M-5A") 0.31 Parts by mass, 2.35 parts by mass of trimethylolpropane-modified tolylene diisocyanate (manufactured by Toyo Chem Co., Ltd., trade name "BHS 8515") as an isocyanate crosslinking agent, and 3-glycidoxypropylmethyldimethoxysilane (silane coupling agent) Shin-Etsu Chemical Co., Ltd., trade name "KBM-403" (trade name) 0.5 parts by mass was mixed and diluted with methyl ethyl ketone to prepare a coating solution of a tacky composition having a solid content concentration of 30%.

  The resulting coating solution is coated on a release-treated surface of a release sheet (trade name “PET 251130”, manufactured by Lintec Corporation, trade name “PET 251130”) obtained by release-treating one side of a polyethylene terephthalate film with a silicone release agent, then 1 Heated for a minute. Thereby, the 2nd laminated body by which the coating film of the adhesive composition was laminated | stacked on the peeling process surface of the peeling sheet was obtained.

3. Production of Pressure-Sensitive Adhesive Sheet for Battery The surface of the first laminate produced as described above on the hard coat layer side and the surface of the adhesive composition of the second laminate produced as described above on the coating side are bonded Then, it was aged at 23 ° C. and 50% RH for 7 days. Thereby, the adhesive sheet for batteries in which the coating film of the adhesive composition became an adhesive layer was obtained. The thickness of the pressure-sensitive adhesive layer was 7 μm. The thickness of the said adhesive layer calculated | required by calculating | requiring the total thickness of the adhesive sheet for batteries, and deducting the thickness of a 1st laminated body and the said peeling sheet from the said total thickness.

[Examples 2 and 3]
A pressure-sensitive adhesive sheet for a battery was produced in the same manner as in Example 1 except that the thickness of the hard coat layer was changed as shown in Table 1.

Example 4
As the inorganic oxide fine particles, an alumina sol (hereinafter referred to as “alumina sol B”) different from the alumina sol A in the dispersed state in the coating solution for the composition for hard coat layer described above is used, and the thickness of the hard coat layer is A pressure-sensitive adhesive sheet for a battery was produced in the same manner as in Example 1 except that the changes were made as shown in 1. In the prepared coating solution for a hard coat layer, the solid content concentration is 16%, the viscosity at 23 ° C. is 2.75 mPa · s, and the volume ratio of pentaerythritol triacrylate to alumina sol is 65 It was 35 (≒ 100: 54). Moreover, content of the inorganic oxide particle in a hard-coat layer was 0.7 cm < ³ > / m < ² >.

[Example 5]
As the inorganic oxide fine particles, an alumina sol (hereinafter referred to as "alumina sol C") different from the alumina sol A in the dispersed state in the coating solution for the composition for hard coat layer is used, and the compounding amount is 600 parts by mass. A pressure-sensitive adhesive sheet for a battery was produced in the same manner as in Example 1 except for the change. In the prepared coating solution for a hard coat layer, the solid content concentration is 30%, the viscosity at 23 ° C. is 2.42 mPa · s, and the volume ratio of pentaerythritol triacrylate to alumina sol is 38 : 62 (62 100: 163). Moreover, content of the inorganic oxide particle in a hard-coat layer was 1.2 cm < ³ > / m < ² >.

Comparative Example 1
As the inorganic oxide fine particles, an alumina sol (hereinafter referred to as “alumina sol D”) different from the alumina sol A in the dispersed state in the coating solution for the composition for hard coat layer is used, and the thickness of the hard coat layer is A pressure-sensitive adhesive sheet for a battery was produced in the same manner as in Example 1 except that the changes were made as shown in 1. In the prepared coating solution for a hard coat layer, the solid content concentration is 16%, the viscosity at 23 ° C. is 3.08 mPa · s, and the volume ratio of pentaerythritol triacrylate to alumina sol is 65 It was 35 (≒ 100: 54). In addition, the content of inorganic oxide particles in the hard coat layer was 0.4 cm ³ / m ² .

Comparative Example 2
A pressure-sensitive adhesive sheet for a battery was produced in the same manner as in Example 1, except that the alumina sol B described above was used as the inorganic oxide fine particles, and the thickness of the hard coat layer was changed as shown in Table 1. In the prepared coating solution for a hard coat layer, the solid content concentration is 16%, the viscosity at 23 ° C. is 2.75 mPa · s, and the volume ratio of pentaerythritol triacrylate to alumina sol is 65 It was 35 (≒ 100: 54). In addition, the content of inorganic oxide particles in the hard coat layer was 0.4 cm ³ / m ² .

Comparative Example 3
While using the alumina sol C described above as the inorganic oxide fine particles, changing the compounding amount to 360 parts by mass and further changing the thickness of the hard coat layer as shown in Table 1, the battery is carried out in the same manner as Example 1 Adhesive sheet was manufactured. The solids concentration in the coating solution for the hard coat layer composition prepared is 16%, the viscosity at 23 ° C. is 2.31 mPa · s, and the volume ratio of pentaerythritol triacrylate to alumina sol is 50 : 50 (50 100: 100). Moreover, content of the inorganic oxide particle in a hard-coat layer was 1.0 cm < ³ > / m < ² >.

[Test example 1] (Measurement of haze value)
The haze value (%) of the laminate (first laminate) of the hard coat layer and the substrate produced in Examples and Comparative Examples, and the haze value (%) of the substrates used in Examples and Comparative Examples Each was measured using a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., trade name "NDH 5000"). The results are shown in Table 1.

  In addition, the haze value (%) of the laminate of the hard coat layer and the substrate (expressed as "A" in Table 1) indicates the haze value (%) of the substrate (expressed as "B" in Table 1). The value obtained by subtracting was calculated. The results are shown in Table 1 as "A-B". In Table 1, the thickness of the hard coat layer is represented as "X", and the value of "A-B" is represented as "Y".

  Further, in FIG. 4, the thickness (X) (μm) of the hard coat layer is taken as the horizontal axis, and the haze value (%) of the laminate of the hard coat layer and the substrate is the haze value (%) of the substrate What plotted the example and the comparative example is shown in the graph which makes a vertical axis the value (Y) obtained by subtracting. In the graph, a straight line satisfying Y = -12 X + 30 is also indicated by a broken line.

[Test Example 2] (Insulation Evaluation at Normal Time)
The release sheet was peeled off from the pressure-sensitive adhesive sheet for batteries obtained in Examples and Comparative Examples, and the exposed pressure-sensitive adhesive layer was attached to an aluminum plate (thickness: 1 mm), and this was used as a test piece. Using a tester (trade name “Digital High Tester 3802-50” manufactured by Hioki Electric Co., Ltd.), contact the terminals of the tester with each of the battery adhesive sheet located on the surface of the test piece and the aluminum plate located on the back surface, The resistance value of the thickness direction of the adhesive sheet for batteries was measured. This measurement was performed on each of the five samples of each example, and among the five measurements, the number of samples having a measured value of 1.0 × 10 ¹⁰ Ω or more was counted. The number of samples is shown in Table 1. Furthermore, based on the said number of samples, the insulation at the time of the normal time of the adhesive sheet for batteries was evaluated by the following judgment criteria. The results are shown in Table 1.
... ... 5 samples have a measured value of 1.0 × 10 ¹⁰ Ω or more.
X: Four or less samples have measured values of 1.0 × 10 ¹⁰ Ω or more.

[Test Example 3] (Insulation evaluation after high temperature heating)
The test pieces obtained in the same manner as in Test Example 2 were heated under a nitrogen atmosphere environment at 80 ° C. for 1 hour. Thereafter, in the same manner as in Test Example 2, a test was performed to measure the resistance value in the thickness direction of the pressure-sensitive adhesive sheet for a battery. Table 1 shows the number of samples having a measured value of 1.0 × 10 ¹⁰ Ω or more in this test. Furthermore, based on the said number of samples, the insulation after the high temperature heating of the adhesive sheet for batteries was evaluated by the following judgment criteria. The results are shown in Table 1.
... ... 5 samples have a measured value of 1.0 × 10 ¹⁰ Ω or more.
X: Four or less samples have measured values of 1.0 × 10 ¹⁰ Ω or more.

[Test Example 4] (Evaluation of Insulating Property after Electrolyte Durability Test)
A test piece obtained in the same manner as in Test Example 2 was mixed with ethylene carbonate and diethyl carbonate in a volume ratio of 1: 1 as an electrolyte solution to prepare a 1 mol / L lithium hexafluorophosphate (LiPF ₆ ) solution. It was enclosed in an aluminum laminate bag together with a preparation solution dissolved at a concentration, and heated for 4 weeks in an environment of 80 ° C. (electrolyte durability test). Thereafter, in the same manner as in Test Example 2, a test was performed to measure the resistance value in the thickness direction of the pressure-sensitive adhesive sheet for a battery (after electrolyte durability). Table 1 shows the number of samples having a measured value of 1.0 × 10 ¹⁰ Ω or more in this test. Furthermore, based on the said number of samples, the insulation after the electrolyte solution endurance test of the adhesive sheet for batteries was evaluated by the following judgment criteria. The results are shown in Table 1. In addition, the object of the insulation evaluation after this electrolyte solution endurance test was taken only as to Examples 1 to 5 which obtained the evaluation of "o" in Test Example 3.
... ... 5 samples have a measured value of 1.0 × 10 ¹⁰ Ω or more.
X: Four or less samples have measured values of 1.0 × 10 ¹⁰ Ω or more.

[Test Example 5] (Evaluation of curl)
A first laminate made of a substrate and a hard coat layer, which was produced in the same manner as in Examples and Comparative Examples, was cut to a size of 50 mm × 50 mm as a test piece. The obtained test piece was placed on a horizontal table, and the vertical distance (mm) from the table surface at the four corners of the test piece was measured under an atmosphere of 23 ° C. and 50% RH, and the average value (mm) was calculated. . Based on this average value, the curl of the adhesive sheet for batteries was evaluated according to the following judgment criteria. The results are shown in Table 1.
... ... The average value is less than 60 mm.
X: The average value is 60 mm or more.

[Test Example 6] (Evaluation of scratch resistance)
About the 1st laminated body which consists of a base material and a hard-coat layer produced similarly to the Example and the comparative example, it mounted on the horizontal stand so that the hard-coat layer side might become an upper side. Then, the surface of the hard coat layer was rubbed with a load of 100 g / cm ² for 10 cm for 10 cycles using # 0000 steel wool, and the presence or absence of a scratch was confirmed. And the abrasion resistance of the adhesive sheet for batteries was evaluated by the following judgment criteria. The results are shown in Table 1.
... ... substantially no damage occurred.
... ... several thin scratches occurred.
X ... several distinct scratches occurred.

  As apparent from Table 1, the pressure-sensitive adhesive sheet for a battery according to the example is excellent in insulation even in the normal state, even when heated at a high temperature, or when immersed in an electrolytic solution for a long time It was a thing. Moreover, the adhesive sheet for batteries of the example was hardly curled. Furthermore, the adhesive sheet for batteries of the example was excellent in abrasion resistance.

  The pressure-sensitive adhesive composition and the pressure-sensitive adhesive sheet for a battery according to the present invention are suitable for attaching an electrode extraction tab to an electrode in a lithium ion battery.

DESCRIPTION OF SYMBOLS 1 ... Battery adhesive sheet 11 ... Base material 12 ... Hard-coat layer 13 ... Adhesive layer 14 ... Peeling sheet 2 ... Lithium ion battery 21 ... Exterior body 22 ... Positive electrode terminal 23 ... Negative electrode terminal 24 ... Electrode body 241 ... Positive electrode current collection Body 241a ... positive electrode active material layer 242 ... negative electrode current collector 242a ... negative electrode active material layer 243 ... separator 244 ... electrode extraction tab

Claims (4)

A substrate,
A hard coat layer provided on one side of the substrate;
And a pressure-sensitive adhesive layer provided on the side of the hard coat layer opposite to the substrate,
The hard coat layer is formed of a composition for a hard coat layer containing inorganic oxide fine particles having an insulating property,
When the thickness of the hard coat layer is X μm, and the value obtained by subtracting the haze value (%) of the substrate from the haze value (%) of the laminate of the substrate and the hard coat layer is Y In addition, the numerical values represented by X and Y are condition 1 and condition 2 below.
(Condition 1) Y − -12X + 30
(Condition 2) X> 0
An adhesive sheet for a battery, characterized in that   The pressure-sensitive adhesive sheet for a battery according to claim 1, wherein the inorganic oxide fine particles are metal oxide fine particles. The hard coat layer, the inorganic oxide particles, 0.01 cm ³ / ^{m 2} or more, the battery adhesive sheet according to claim 1 or 2, characterized in that it contains ^{7 cm} 3 / ^{m 2} or less.   It fixes in the state which two or more conductors contacted in the inside of a battery using the adhesive sheet for batteries as described in any one of Claims 1-3. battery.

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