Adhesive composition and heat-sealable member using the same

Abstract

To provide an adhesive composition having high room-temperature peel strength, high hot peel strength, and excellent adhesion, as well as excellent electrolyte resistance even when used in packaging materials for lithium ion batteries, and a heat-fusible member including the adhesive composition.SOLUTION: An adhesive composition contains an organic solvent, a polyolefin (A) that has an acidic group and / or an acid anhydride group and is soluble in the organic solvent, and an isocyanate compound, wherein the isocyanate compound comprises (B) a diisocyanate compound having a C4-7 hydrocarbon group and / or a derivative thereof, and (C) a diisocyanate compound having a C8-14 hydrocarbon group and / or a derivative thereof. There is also provided a heat-fusible member including the adhesive composition.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an adhesive composition and a heat-sealable member using the same, and can be used in various industrial product fields such as the electrical field, the automotive field, and the industrial field, and belongs to these technical fields.

Background Art

[0002] Hot-melt type adhesive compositions are processed into film or sheet form for use, and are used in various industrial product fields such as the electrical field, the automotive field, and the industrial field as adhesive films or sheets in which the adhesive composition is laminated on the surface of a member. In order to bond metal members such as iron, aluminum, titanium, and other metals, and their alloys, etc., used in these fields, and molded bodies made of polyolefin with poor adhesiveness, various adhesive compositions have been proposed. Patent Document 1 discloses an adhesive composition obtained by dissolving and dispersing components composed of a carboxylic acid-containing polyolefin, a carboxylic acid-containing epoxy resin, a polyisocyanate compound, and, if necessary, an epoxy resin in an organic solvent. Patent Document 2 discloses an adhesive composition containing a polyolefin having a carboxyl group or an acid anhydride group, a polyfunctional isocyanate compound, and a solvent, wherein the glass transition temperature, melting point, and melting energy of the polyolefin are specific values.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, although the adhesive compositions described in Patent Documents 1 and 2 have an adhesiveness at room temperature (hereinafter referred to as "room temperature peel strength") of 5 N / 15 mm or more, which is in the practical range, there is still room for improvement, and the adhesiveness at a high temperature of about 80°C (hereinafter referred to as "hot peel strength") is insufficient. In addition, when a packaging material for a lithium-ion battery is manufactured using these adhesive compositions, although the packaging material does not come into contact with the electrolyte during normal use, adhesiveness (hereinafter referred to as "electrolyte resistance") after immersion in an electrolyte at a high temperature of about 80°C in case of an abnormality is required, but there is a problem of insufficiency. An object of the present invention is to provide an adhesive composition having a room temperature peel strength of 20 N / 15 mm or more, a hot peel strength of 10 N / 15 mm or more, excellent adhesiveness, and excellent electrolyte resistance even when used for a packaging material for a lithium-ion battery, and a heat-sealable member using the same.

Means for Solving the Problems

[0005] As a result of intensive studies to solve the above problems, the present inventors have found that an adhesive composition containing an organic solvent, a polyolefin having an acidic group and / or an acid anhydride group dissolved in the organic solvent, and two specific isocyanate compounds has high room temperature peel strength and hot peel strength, excellent adhesiveness, and excellent electrolyte resistance even when used for a packaging material for a lithium-ion battery, and thus completed the present invention.

[0006] That is, according to one aspect of the present invention, An adhesive composition containing an organic solvent, a polyolefin (A) having an acidic group and / or an acid anhydride group dissolved in the organic solvent, and an isocyanate compound, wherein the isocyanate compound contains a diisocyanate compound having a hydrocarbon group having 4 to 7 carbon atoms and / or a derivative (B) thereof, and a diisocyanate compound having a hydrocarbon group having 8 to 14 carbon atoms and / or a derivative (C) thereof. According to a preferred embodiment of the adhesive composition of the present invention, the diisocyanate compound having a hydrocarbon group with 4 to 7 carbon atoms is hexamethylene diisocyanate. According to another preferred embodiment of the adhesive composition of the present invention, the diisocyanate compound having a hydrocarbon group with 8 to 14 carbon atoms is a diisocyanate compound having at least one secondary isocyanate group. According to another preferred embodiment of the adhesive composition of the present invention, the diisocyanate compound having a hydrocarbon group with 8 to 14 carbon atoms is isophorone diisocyanate. According to another preferred embodiment of the adhesive composition of the present invention, the derivative of the diisocyanate compound having a hydrocarbon group with 4 to 7 carbon atoms and / or the derivative of the diisocyanate compound having a hydrocarbon group with 8 to 14 carbon atoms contains at least one bond selected from the group consisting of isocyanurate bond, burette bond, urethane bond, and allophanate bond. According to another preferred embodiment of the adhesive composition of the present invention, the component (A) is a polyolefin graft-modified with an acidic group-containing monomer and / or an acid anhydride group-containing monomer, and the graft amount thereof is 0.10 to 30% by weight. According to another preferred embodiment of the adhesive composition of the present invention, the component (A) is a polyolefin graft-modified with an esterified product of an alkyl alcohol having 8 to 18 carbon atoms and (meth)acrylic acid, and the graft amount thereof is 0.10 to 20% by weight. According to another preferred embodiment of the adhesive composition of the present invention, the weight average molecular weight of the component (A) is 15,000 to 200,000. According to another aspect of the present invention, there is provided a heat-sealable member comprising an adhesive layer formed by curing the adhesive composition of the present invention, a metal layer joined to one side of the adhesive layer, and a heat-sealable resin layer joined to the other side of the adhesive layer. According to still another aspect of the present invention, there is provided a packaging material for a lithium ion battery including the heat-sealable member of the present invention.

Advantages of the Invention

[0007] According to the present invention, there are provided an adhesive composition having high room temperature peel strength and hot peel strength, excellent adhesiveness, and excellent electrolyte resistance even when used as a packaging material for lithium ion batteries, and a heat-sealable member using the same.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0009] The present invention relates to an adhesive composition containing an organic solvent, a polyolefin (A) having an acidic group and / or an acid anhydride group dissolved in the organic solvent, and an isocyanate compound, wherein the isocyanate compound is a diisocyanate compound having a hydrocarbon group having 4 to 7 carbon atoms and / or a derivative (B) thereof, and a diisocyanate compound having a hydrocarbon group having 8 to 14 carbon atoms and / or a derivative (C) thereof. Hereinafter, the component (A), component (B), component (C), organic solvent, other components, adhesive composition, method for producing the adhesive composition, heat-sealable member, method for producing the heat-sealable member, and uses will be described. In the present specification, acrylic acid and / or methacrylic acid is represented as (meth)acrylic acid.

[0010] 1. Component (A) The component (A) is a polyolefin having an acidic group and / or an acid anhydride group.

[0011] As the component (A), a polyolefin modified with an acidic group-containing monomer and / or an acid anhydride group-containing monomer is preferable in terms of high room temperature peel strength and high hot peel strength.

[0012] As the component (A), a polyolefin modified with a (meth)acrylate is preferable in terms of excellent solubility in an organic solvent and compatibility with other resins.

[0013] Specific examples of the polyolefin constituent monomer units of the component (A) include ethylene, propylene, and α-olefins such as 1-butene, isobutylene, 1-hexene, and 1-octene. Among these, when a difficult-to-adhere non-polar polyolefin resin such as crystalline polyethylene or polypropylene is used as the adherend, ethylene, propylene, and 1-butene are preferable in terms of improving the hot peel strength and electrolyte resistance.

[0014] Specific examples of the acidic group include carboxylic acid groups, sulfonic acid groups, and phosphoric acid groups, etc. Among these, carboxylic acid groups are preferable in terms of easy modification.

[0015] Specific examples of the acid anhydride group include carboxylic acid anhydride groups, sulfonic acid anhydride groups, and phosphoric acid anhydride groups, etc. Among these, carboxylic acid anhydride groups are preferable in terms of easy availability of raw materials and easy modification.

[0016] As the modification method, known methods can be adopted. For example, in melt kneading or in an organic solvent, in the presence of a known radical polymerization initiator such as an organic peroxide or an aliphatic azo compound, graft modification in which an acidic group-containing monomer and / or an acid anhydride group-containing monomer is added to the polyolefin, and copolymerization of an acidic group-containing monomer and / or an acid anhydride group-containing monomer with olefins, etc. can be mentioned.

[0017] The component (A) may further be graft-modified with an alkyl (meth)acrylate. As the alkyl (meth)acrylate, an esterified product of an alkyl alcohol having 8 to 18 carbon atoms and (meth)acrylic acid (hereinafter referred to as “long-chain alkyl (meth)acrylate”) is preferable.

[0018] When the (A) component is a polyolefin graft-modified with an acidic group-containing monomer, an acid anhydride group-containing monomer, and a long-chain alkyl (meth)acrylate, examples of the raw polyolefin include polyethylene, polypropylene, a random copolymer of propylene and ethylene, a block copolymer of propylene and ethylene, a random copolymer of ethylene and an α-olefin, a block copolymer of ethylene and an α-olefin, a random copolymer of propylene and an α-olefin, and a block copolymer of propylene and an α-olefin.

[0019] Among these, when using a difficult-to-adhere non-polar polyolefin resin such as crystalline polyethylene or polypropylene as the adherend, polypropylene-based polymers such as propylene-ethylene copolymers, propylene-1-butene copolymers, and propylene-ethylene-1-butene copolymers are preferred in terms of improving the hot peel strength and electrolyte resistance. Furthermore, it is particularly preferred that the propylene unit in the polyolefin is 50% by weight or more.

[0020] In order to improve the graft amount of the acidic group-containing monomer, the acid anhydride group-containing monomer, and the long-chain alkyl (meth)acrylate in the (A) component, it is preferable to use organic peroxides such as benzoyl peroxide, dicumyl peroxide, lauroyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, and cumene hydroperoxide, or stabilizers for adjusting the reaction aid and resin stability can be used.

[0021] Specific examples of the reaction aid include styrene, o-methylstyrene, p-methylstyrene, α-methylstyrene, divinylbenzene, hexadiene, and dicyclopentadiene.

[0022] Specific examples of the stabilizer include hydroquinone, benzoquinone, and nitrosophenylhydroxy compounds.

[0023] 1-1. Monomer containing acidic group As the acidic group-containing monomer serving as the raw material of the (A) component, it is a compound having an ethylenic double bond and a carboxylic acid group or the like in the same molecule, and examples thereof include various unsaturated monocarboxylic acid compounds, unsaturated dicarboxylic acid compounds, and unsaturated tricarboxylic acid compounds.

[0024] Specific examples of the unsaturated monocarboxylic acid compound include acrylic acid, methacrylic acid, crotonic acid, and isocrotonic acid.

[0025] Specific examples of the unsaturated dicarboxylic acid compound include maleic acid, itaconic acid, citraconic acid, tetrahydrophthalic acid, nadic acid, and endic acid.

[0026] Examples of the unsaturated tricarboxylic acid compound include aconitic acid.

[0027] As the acidic group-containing monomer, unsaturated dicarboxylic acid compounds and unsaturated tricarboxylic acid compounds are preferable in terms of easy modification and excellent adhesiveness, and itaconic acid, maleic acid, and aconitic acid are particularly preferable.

[0028] These acidic group-containing monomers may be used alone or in combination of two or more.

[0029] When a part of the acidic group-containing monomer used for modification is unreacted, it may be removed by known methods such as heating and distilling off and reprecipitation purification as necessary.

[0030] When the (A) component is a polyolefin graft-modified with an acidic group-containing monomer, the graft amount is preferably 0.10 to 30% by weight based on the graft-modified product. In terms of maintaining solubility in a solvent and adhesiveness to materials such as a metal adherend, 0.10% by weight or more is preferable, and 0.50% by weight or more is more preferable. Also, in terms of obtaining sufficient adhesiveness, 30% by weight or less is preferable, 20% by weight or less is more preferable, and 10% by weight or less is particularly preferable.

[0031] The graft amount of the acidic group-containing monomer can be measured by a known method. For example, it can be determined by an alkali titration method or Fourier transform infrared spectroscopy.

[0032] 1-2. Monomer containing acid anhydride group The acid anhydride group-containing monomer used as the raw material of the component (A) is a compound having an ethylenic double bond and a carboxylic acid anhydride group, etc. in the same molecule, and includes the acid anhydride of the unsaturated monocarboxylic acid compound, the acid anhydride of the unsaturated dicarboxylic acid compound, and the acid anhydride of the unsaturated tricarboxylic acid compound, etc.

[0033] Specific examples of the acid anhydride of the unsaturated monocarboxylic acid compound include acrylic anhydride, methacrylic anhydride, crotonic anhydride, and isocrotonic anhydride, etc.

[0034] Specific examples of the acid anhydride of the unsaturated dicarboxylic acid compound include maleic anhydride, itaconic anhydride, citraconic anhydride, tetrahydrophthalic anhydride, nadic anhydride, and endic anhydride, etc.

[0035] Specific examples of the acid anhydride of the unsaturated tricarboxylic acid compound include aconitic anhydride, etc.

[0036] As the acid anhydride group-containing monomer, the acid anhydride of the unsaturated dicarboxylic acid compound and the acid anhydride of the unsaturated tricarboxylic acid compound are preferable in terms of easy modification and excellent adhesiveness, and itaconic anhydride, maleic anhydride, and aconitic anhydride are particularly preferable.

[0037] These acid anhydride group-containing monomers may be used alone or in combination of two or more.

[0038] When a part of the acid anhydride group-containing monomer used for modification is unreacted, it may be removed by a known method such as heating and distilling off and reprecipitation purification as necessary.

[0039] In the case of a polyolefin graft-modified with an acid anhydride group-containing monomer as the component (A), the graft amount is preferably 0.10 to 30% by weight based on the graft-modified product. From the viewpoint of maintaining solubility in a solvent and adhesiveness to materials such as a metal adherend, 0.10% by weight or more is preferable, and 0.50% by weight or more is more preferable. Further, from the viewpoint of obtaining sufficient adhesiveness, 30% by weight or less is preferable, 20% by weight or less is more preferable, and 10% by weight or less is particularly preferable.

[0040] The graft amount of the acid anhydride group-containing monomer can be measured by a known method. For example, it can be determined by an alkali titration method or a Fourier transform infrared spectroscopy method.

[0041] 1-3. (Meth)acrylic acid long-chain alkyl ester Specific examples of the (meth)acrylic acid long-chain alkyl ester as the raw material of the component (A) include octyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, and stearyl (meth)acrylate. Among them, octyl (meth)acrylate, lauryl (meth)acrylate, and tridecyl (meth)acrylate are preferable in terms of improving adhesiveness when a poorly adherent non-polar polyolefin resin is used as an adherend.

[0042] The graft amount of the (meth)acrylic acid long-chain alkyl ester in the component (A) is preferably 0.10 to 20% by weight based on the graft-modified product. From the viewpoints of maintaining good solubility of the component (A) in a solvent, compatibility with other resins, and adhesiveness, 0.10% by weight or more is preferable. Further, from the viewpoint of maintaining good adhesiveness, 20% by weight or less is preferable, 10% by weight or less is more preferable, and 5.0% by weight or less is particularly preferable.

[0043] The graft amount of the (meth)acrylic acid long-chain alkyl ester can be measured by a known method. For example, it can be determined by a Fourier transform infrared spectroscopy method or 1 an H-NMR method.

[0044] In the present invention, depending on the purpose, monomers other than the acidic group-containing monomer, the acid anhydride group-containing monomer, and the (meth)acrylic acid long-chain alkyl ester (hereinafter referred to as "other monomers") can be used in combination within a range that does not impair the characteristics of the present invention.

[0045] Specific examples of other monomers include (meth)acrylic acid esters other than the above, such as hydroxyethyl (meth)acrylate, benzyl (meth)acrylate, glycidyl (meth)acrylate, and isocyanate-containing (meth)acrylic acid; unsaturated monomers copolymerizable with olefins, such as styrene, cyclohexyl vinyl ether, and dicyclopentadiene.

[0046] By using other monomers in combination, the adhesiveness, solubility in solvents, and the graft amount of the acidic group-containing monomer, the acid anhydride group-containing monomer, and the (meth)acrylic acid long-chain alkyl ester can be further improved. It is desirable that the amount of other monomers used does not exceed the total graft amount of the acidic group-containing monomer, the acid anhydride group-containing monomer, and the (meth)acrylic acid long-chain alkyl ester.

[0047] (A) component may be a polyolefin having an acidic group and / or an acid anhydride group, and an ethylenically unsaturated group, within a range that does not impair the characteristics of the present invention, depending on the purpose. As a method for introducing an ethylenically unsaturated group into the (A) component, for example, a method of adding a hydroxyl group-containing ethylenically unsaturated monomer such as hydroxyethyl (meth)acrylate and an epoxy group-containing ethylenically unsaturated monomer such as glycidyl (meth)acrylate to the acidic group and / or the acid anhydride group can be mentioned.

[0048] The weight average molecular weight of the (A) component is preferably 15,000 to 200,000. It is preferably 15,000 or more, more preferably 30,000 or more, in terms of improving the peel strength at room temperature and the electrolytic solution resistance. It is preferably 200,000 or less, more preferably 150,000 or less, in terms of improving the solubility in the organic solvent in the adhesive composition.

[0049] In the present invention, the weight-average molecular weight is a value obtained by converting the molecular weight measured by gel permeation chromatography into polystyrene equivalent molecular weight.

[0050] As the melting point of the component (A), 50 to 100 °C is preferable. From the viewpoint of obtaining sufficient peel strength, 50 °C or higher is preferable, and 60 °C or higher is more preferable. Further, from the viewpoint of obtaining sufficient storage stability at low temperatures, 100 °C or lower is preferable, and 95 °C or lower is more preferable.

[0051] As the adhesive composition of the present invention, only one kind or two or more kinds of the component (A) may be used in combination.

[0052] The content of the component (A) is preferably 80 to 100% by weight, more preferably 90 to 100% by weight, based on 100% by weight of the solid content of the adhesive composition, in terms of excellent hot peel strength and electrolytic solution resistance.

[0053] 2. Isocyanate compound As the isocyanate compound of the present invention, a diisocyanate compound having a hydrocarbon group with 4 to 7 carbon atoms and / or its derivative (B) and a diisocyanate compound having a hydrocarbon group with 8 to 14 carbon atoms and / or its derivative (C) are used in combination.

[0054] The component (B) has an effect of improving the adhesion to the adherend, and the component (C) has a high effect of increasing the crosslink density of the cured product and improving the hot peel strength because of its good compatibility with the component (A).

[0055] 2-1. Component (B) The component (B) is a diisocyanate compound having a hydrocarbon group with 4 to 7 carbon atoms (hereinafter referred to as the component (b)) and / or its derivative.

[0056] Specific examples of component (b) include hexamethylene diisocyanate, pentamethylene diisocyanate, tetramethylene diisocyanate, etc. As component (b), hexamethylene diisocyanate is preferred in that it has a high effect of improving the adhesion to the adherend.

[0057] As the derivative of component (b), a compound containing at least one bond selected from the group consisting of isocyanurate bond, biuret bond, urethane bond and allophanate bond is preferred. A compound containing an isocyanurate bond is particularly preferred in that it has a high effect of improving the adhesion to the adherend and can improve the peel strength at room temperature and the electrolyte resistance.

[0058] The derivative of component (b) may have a urea bond and / or a uretdione bond.

[0059] As the derivative of component (b), commercially available products can be used. Commercially available products of compounds having an isocyanurate bond include Duranate TPA-100 (manufactured by Asahi Kasei Corporation), Duranate MFA-75B (manufactured by Asahi Kasei Corporation), Duranate TUL-100 (manufactured by Asahi Kasei Corporation), Duranate TSA-100 (manufactured by Asahi Kasei Corporation), Coronate HX (manufactured by Tosoh Corporation), and Takenate D-170N (manufactured by Mitsui Chemicals, Inc.), etc. Commercially available products of compounds having a biuret bond include Duranate 24A-100 (manufactured by Asahi Kasei Corporation), Duranate 21S-75E (manufactured by Asahi Kasei Corporation), Takenate D-165NN (manufactured by Mitsui Chemicals, Inc.), and Desmodur N3200 (manufactured by Sumitomo Bayer Urethane Co., Ltd.), etc. Commercially available products of compounds having a urethane bond include Duranate P301-75E (manufactured by Asahi Kasei Corporation), which is an adduct of hexamethylene diisocyanate and trimethylolpropane, and Sumidur HT (manufactured by Sumitomo Bayer Urethane Co., Ltd.), etc. Commercially available products of compounds having an allophanate bond include Desmodur XP2580 (manufactured by Sumitomo Bayer Urethane Co., Ltd.), etc.

[0060] 2-2. Component (C) The (C) component is a diisocyanate compound having a hydrocarbon group with 8 to 14 carbon atoms (hereinafter referred to as the "(c) component") and / or its derivative.

[0061] Specific examples of the (c) component include diisocyanate compounds having one secondary isocyanate group such as isophorone diisocyanate and norbornane diisocyanate, diisocyanate compounds having two secondary isocyanate groups such as 4,4'-methylenebis(cyclohexyl isocyanate), and diisocyanate compounds having no secondary isocyanate group such as dodecane diisocyanate and 1,3-bis(isocyanatemethyl)cyclohexane.

[0062] As the (c) component, a diisocyanate compound having at least one secondary isocyanate group is preferable in terms of having a high effect of improving the electrolyte resistance. Among these, isophorone diisocyanate is particularly preferable.

[0063] As the derivative of the (c) component, a compound containing at least one bond selected from the group consisting of isocyanurate bond, burette bond, urethane bond, and allophanate bond is preferable, and a compound containing an isocyanurate bond is particularly preferable in terms of having a high effect of improving the thermal peel strength.

[0064] The derivative of the (c) component may have a urea bond and / or a uretdione bond.

[0065] Commercially available products can be used as the derivative of the (c) component. Commercially available products of compounds having an isocyanurate bond include Desmodur Z4470 BA (manufactured by Sumitomo Bayer Urethane Co., Ltd.) and Duranate T4900-70B (manufactured by Asahi Kasei Corporation). Commercially available products of compounds having an allophanate bond include Desmodur XP2565 (manufactured by Sumitomo Bayer Urethane Co., Ltd.). Examples of commercially available products of compounds having urethane bonds include Takenate D-140N (manufactured by Mitsui Chemicals, Inc.), which is an adduct of isophorone diisocyanate and trimethylolpropane, and VESTANAT EP-DC1241 (manufactured by Evonik Japan Co., Ltd.), which is a mono-adduct of isophorone diisocyanate and hydroxyethyl acrylate.

[0066] The weight ratio of component (A) and the isocyanate compound in the adhesive composition of the present invention is not particularly limited, but the equivalent ratio (NCO / OH) of the isocyanate group of the isocyanate compound to the carboxylic acid group of component (A) is preferably from 0.01 to 12.0. From the viewpoint of excellent initial adhesiveness, it is preferably 0.01 or more, more preferably 0.04 or more, and particularly preferably 0.1 or more. Also, from the viewpoint of forming a cured product having a sufficient crosslink density and excellent flexibility, etc., it is preferably 12.0 or less, more preferably 9.0.

[0067] In the adhesive composition of the present invention, when the total amount of component (B) and component (C) is 100% by weight, the weight ratio of component (B) and component (C) is preferably 10 to 80% by weight for component (B) and 20 to 90% by weight for component (C) from the viewpoint of improving the adhesion to the adherend, more preferably 20 to 50% by weight for component (B) and 50 to 80% by weight for component (C) from the viewpoint of enhancing the crosslink density of the cured product and improving the hot peel strength.

[0068] 3. Organic solvent In the adhesive composition of the present invention, the organic solvent is blended for the purpose of dissolving component (A).

[0069] Specific examples of the organic solvent include aromatic organic solvents such as toluene and xylene, aliphatic organic solvents such as n-hexane, alicyclic organic solvents such as cyclohexane, methylcyclohexane, and ethylcyclohexane, ketone organic solvents such as acetone and methyl ethyl ketone, alcohol organic solvents such as methanol and ethanol, ester organic solvents such as ethyl acetate and butyl acetate, and propylene glycol ether organic solvents such as propylene glycol methyl ether, propylene glycol ethyl ether, and propylene glycol-t-butyl ether, etc.

[0070] As the adhesive composition of the present invention, only one kind of organic solvent may be used, or two or more kinds may be used in combination.

[0071] As the organic solvent, an organic solvent that can be easily volatilized and removed by heating etc. of the adhesive composition is preferable, and in particular, it is preferable to use a mixed solvent of an alicyclic organic solvent and an ester-based or ketone-based organic solvent. Also, from the viewpoints of the solubility of the component (A) and environmental problems, it is preferable not to use an aromatic organic solvent.

[0072] In the adhesive composition of the present invention, the weight ratio of the organic solvent and the component (A) is not particularly limited, and this weight ratio can be set according to the types of the organic solvent and the modified polyolefin-based resin, etc.

[0073] When the total of the organic solvent and the component (A) is 100% by weight, the content of the component (A) is preferably 5 to 25% by weight, particularly preferably 10 to 20% by weight. With such a content, it is easy to apply the adhesive composition to the adherend and the workability is excellent.

[0074] 4. Other components The adhesive composition of the present invention contains an organic solvent and the above components (A) to (C), but various components can be blended according to the purpose.

[0075] Specific examples of other components include curing catalysts, styrenic thermoplastic elastomers, tackifiers, antioxidants, hindered amine light stabilizers, ultraviolet absorbers, antistatic agents, flame retardants, colorants, dispersants, adhesion promoters, defoamers, leveling agents, plasticizers, lubricants, fillers, and the like.

[0076] Hereinafter, these components will be described. Note that as for the other components described below, only one kind of the exemplified compounds may be used, or two or more kinds may be used in combination.

[0077] 4-1. Curing catalyst The curing catalyst can be blended for the purpose of promoting the crosslinking reaction between the component (A) and the isocyanate compound and obtaining excellent adhesion performance.

[0078] From the viewpoints of ease of curing and adhesion performance, the adhesive composition of the present invention preferably further contains a curing catalyst. Preferred examples of the curing catalyst include organotin compounds and tertiary amines.

[0079] Specific examples of the organotin compound include dialkyltin fatty acids such as dibutyltin dilaurate, dibutyltin dimaleate, dioctyltin dilaurate, and dioctyltin dimaleate, in which the alkyl group has 3 to 10 carbon atoms.

[0080] Specific examples of the tertiary amine include tetraalkyl ethylenediamines such as tetramethylethylenediamine; N,N'-dialkylbenzylamines such as dimethylbenzylamine; triethylenediamine, pentamethyldiethylenetriamine, N-ethylmorpholine, N-methylmorpholine, 1-methyl-4-dimethylaminoethylpiperazine, and diazabicycloundecene.

[0081] As the curing catalyst, an organotin compound and a tertiary amine can also be used in combination.

[0082] The content ratio of the curing catalyst is preferably 0.001 to 5 parts by weight with respect to 100 parts by weight of the total amount of components (A) to (C). By setting the ratio of the curing catalyst to 0.001 part by weight or more, the catalytic effect can be easily obtained sufficiently, and by setting the ratio of the curing catalyst to 5 parts by weight or less, the storage stability of the adhesive composition can be ensured.

[0083] 4-2. Styrene-based thermoplastic elastomer The styrene-based thermoplastic elastomer can be blended for the purpose of improving the adhesive strength.

[0084] Specific examples of the styrene-based thermoplastic elastomer include styrene-butadiene copolymers, epoxy-modified styrene-butadiene copolymers, styrene-butadiene-styrene block copolymers, styrene-ethylene / propylene-styrene block copolymers (hereinafter referred to as "SEPS"), styrene-ethylene / butylene-styrene block copolymers (hereinafter referred to as "SEBS"), styrene-isoprene / butadiene-styrene block copolymers, styrene-isoprene-styrene block copolymers, and other styrene-based resins. They may have no acidic group and acid anhydride group, or may have an acidic group and / or an acid anhydride group, and may also have an amino group.

[0085] As a modification method for introducing an acidic group and / or an acid anhydride group, a known method can be adopted. For example, graft modification such as melt-kneading the acidic group-containing monomer and / or the acid anhydride group-containing monomer with the styrene-based resin in the presence of a radical polymerization initiator such as an organic peroxide or an aliphatic azo compound can be mentioned.

[0086] As a modification method for introducing an amino group, a known method can be adopted. For example, terminal modification such as adding an amino group-containing compound to the living end of the styrene-based resin obtained by living anionic polymerization, or graft modification such as melt-kneading an amine compound having an unsaturated bond such as 2-(1-cyclohexenyl)ethylamine with the styrene-based resin in the presence of a radical polymerization initiator such as an organic peroxide or an aliphatic azo compound can be mentioned.

[0087] Among these, SEPS and SEBS are preferable in terms of improving the adhesive strength.

[0088] 4-3. Tackifier The tackifier can be blended for the purpose of improving the adhesive strength.

[0089] As the tackifier, known ones can be used, and examples thereof include polyterpene resins, rosin resins, aliphatic petroleum resins, alicyclic petroleum resins, copolymerized petroleum resins, and hydrogenated petroleum resins.

[0090] Specific examples of the polyterpene resin include α-pinene polymers, β-pinene polymers, and copolymers thereof with phenol or bisphenol A.

[0091] Specific examples of the rosin resin include natural rosin, polymerized rosin, and ester derivatives thereof.

[0092] Specific examples of the aliphatic petroleum resin are also called C5 resins and are generally resins synthesized from the C5 fraction of petroleum. The alicyclic petroleum resin is also called C9 resin and is generally a resin synthesized from the C9 fraction of petroleum.

[0093] Specific examples of the copolymerized petroleum resin include C5 / C9 copolymer resins.

[0094] The hydrogenated petroleum resin is generally produced by hydrogenating the above various petroleum resins.

[0095] In terms of excellent hot water resistance, the content of the tackifier is preferably 1 to 20% by weight, more preferably 1 to 10% by weight, based on 100% by weight of the adhesive composition.

[0096] 5. Adhesive composition The adhesive composition of the present invention contains an organic solvent and the components (A) to (C) as essential components.

[0097] The viscosity of the adhesive composition of the present invention at 25°C is preferably 10 to 5,000 mPa·s. From the viewpoint of excellent coatability, 10 mPa·s or more is preferable. Further, from the viewpoint of excellent leveling property, 5,000 mPa·s or less is preferable, and 1,000 mPa·s or less is more preferable.

[0098] The adhesive composition of the present invention is suitable for bonding a polyolefin resin molded body to other members (such as a metal member and a resin member). It can be used not only for bonding polyolefin resin molded bodies such as a polyolefin resin film, but also for bonding a polyolefin resin film to a metal foil made of aluminum or the like, and for bonding a polyolefin resin film to a metal layer in a composite film provided with a resin layer and a metal layer. The adhesive layer obtained from the adhesive composition of the present invention has high peel strength at normal temperature and high peel strength at high temperature, excellent adhesiveness, and high electrolyte resistance, and thus can be preferably used as a packaging material for a lithium ion battery.

[0099] 6. Method for producing adhesive composition The adhesive composition of the present invention can be produced by a known method.

[0100] Specifically, it is a method in which a solution obtained by dissolving the component (A) in an organic solvent is mixed with other components excluding the isocyanate compound, and then the obtained mixture is mixed with the isocyanate compound. The temperature at the time of mixing is usually 40°C or lower, preferably 10°C to 30°C.

[0101] 7. Heat-sealable member The heat-sealable member of the present invention includes an adhesive layer formed by curing the adhesive composition of the present invention, a metal layer joined to one surface side of the adhesive layer, and a heat-sealable resin layer joined to the other surface side of the adhesive layer. A schematic diagram of the heat-sealable member of the present invention is shown in FIGS. 1 and 2. That is, the heat-sealable member 1 in FIG. 1 sequentially includes a heat-sealable resin layer 11, an adhesive layer 12, and a metal layer 13. Further, the heat-sealable member 1 in FIG. 2 sequentially includes a heat-sealable resin layer 11, an adhesive layer 12, a metal layer 13, and another layer 14.

[0102] The shape of the heat-sealable member of the present invention may be appropriately set according to the intended use and the like, and is not particularly limited, and examples thereof include a film shape, a sheet shape, a plate shape, an angle shape, and a rod shape.

[0103] The above heat-sealable resin layer is a layer containing a resin that can be melted by heat and fuse the material constituting the layer on one side and the material constituting the layer on the other side. And this heat-sealable resin layer is preferably a layer containing a resin that melts at a temperature of 50°C to 200°C. Examples of resins having such properties include polyolefin resins, polyamide resins, and polyester resins. Among these, polyolefin resins are preferred because they can be heat-sealed with sufficient strength. Further, as the polyolefin resin, polypropylene is preferred. In particular, when integrating with other members using the heat-sealable member, unstretched polypropylene is more preferred because there is little dimensional change (shrinkage).

[0104] The above heat-sealable resin layer may, if necessary, be a layer containing additives such as lubricants, fillers, heat stabilizers, antioxidants, ultraviolet absorbers, antistatic agents, flame retardants, colorants, dispersants, and adhesion promoters.

[0105] The thickness of the above heat-sealable resin layer is not particularly limited and also depends on the material of the resin and the like. For example, when it is a layer containing unstretched polypropylene, it is preferably 10 to 200 μm, more preferably 20 to 100 μm. If the thickness of the layer containing unstretched polypropylene is 10 to 200 μm, a heat-sealed composite product such as a sealed container with high durability can be obtained without being easily damaged.

[0106] The above-mentioned adhesive layer is a layer formed by curing the adhesive composition of the present invention. The thickness of the adhesive layer is not particularly limited, but is preferably 1 to 20 μm, particularly preferably 2 to 10 μm. If the thickness of the adhesive layer is 1 to 20 μm, processing such as bending is easy when the heat-sealable member is, for example, in the form of a sheet.

[0107] The above-mentioned metal layer is a layer containing a metal or an alloy. Examples of the metal or alloy include aluminum, iron, titanium, magnesium, copper, nickel, chromium and other metals, as well as alloys thereof. Among these, aluminum is preferred because of its excellent workability. The thickness of the metal layer is not particularly limited depending on its material and the like. When the metal layer is made of, for example, aluminum, it is preferably 20 to 100 μm, particularly preferably 20 to 80 μm, and more preferably 30 to 60 μm.

[0108] When the heat-sealable member of the present invention includes a metal layer, as shown in FIG. 2, another layer 14 can be provided on the surface of the metal layer 13. From the viewpoint of protecting the metal layer, the material constituting the other layer preferably contains a resin. That is, the other layer is preferably a resin layer. This resin is not particularly limited and can be a polyamide resin, a polyester resin, or the like. The transparency of the resin layer is not particularly limited, but when the resin layer is transparent or translucent, an excellent appearance can be obtained when a sealed container or the like is used as the heat-sealed composite product. The thickness of the other layer is not particularly limited and is preferably 30 to 60 μm, particularly preferably 30 to 50 μm.

[0109] The heat-sealable member using the adhesive composition of the present invention has high peel strength at room temperature and high peel strength at high temperature, excellent adhesiveness, and excellent resistance to solvents such as electrolytic solutions. Therefore, while maintaining its structure, it can prevent the deterioration of the contents.

[0110] When used as a packaging material for lithium-ion batteries, it can maintain adhesiveness and the like in temperature changes in battery storage or use environments, particularly in the chemical temperature rise of battery constituent materials accompanying charging or discharging, in summer, or in a temperature range higher than normal temperature such as inside an automobile.

[0111] 8. Method for producing heat-sealable member The manufacturing method of the heat-sealable member shown in FIG. 1 is as follows. (1) A method in which an adhesive composition is applied to the surface of a metal foil for forming a metal layer 13, a metal film, etc., then the organic solvent in the composition is removed to form an adhesive layer 12, and then a resin film for forming a heat-sealable resin layer 11 (hereinafter referred to as "heat-sealable resin film") is brought into contact with the surface on which the adhesive layer 12 is formed, and pressure-bonded while heating. (2) A method in which an adhesive composition is applied to the surface of a heat-sealable resin film, then the organic solvent in the composition is removed to form an adhesive layer 12, and then a metal foil for forming a metal layer 13 or the like is brought into contact with the surface on which the adhesive layer 12 is formed, and pressure-bonded while heating.

[0112] Also, the manufacturing method of the heat-sealable member shown in FIG. 2 is as follows. (3) A method in which an adhesive composition is applied to the surface of a metal layer 13 in a composite film having a resin layer constituting another layer 14 and a metal layer 13 formed by vapor deposition or the like on one side of this resin layer, then the organic solvent in the composition is removed to form an adhesive layer 12, and then the surface on which the adhesive layer 12 is formed is brought into contact with a heat-sealable resin film, and pressure-bonded while heating. (4) A method in which an adhesive composition is applied to the surface of a heat-sealable resin film, then the organic solvent in the composition is removed to form an adhesive layer 12, and then the surface on which the adhesive layer 12 is formed is brought into contact with the surface on which a metal layer 13 is formed in a composite film having a resin layer constituting another layer 14 and a metal layer 13 formed by vapor deposition or the like on one side of this resin layer, and pressure-bonded while heating. (5) A method of extrusion-molding a film for forming another layer 14 on the surface of a metal layer 13 in the laminate obtained by the method of (1) or (2) above.

[0113] The adhesive composition is often applied to a material for forming a metal layer such as a metal foil, or to the surface of the metal layer in a composite film including a metal layer and other layers (resin layers), but is not particularly limited. When using a metal foil, it is preferable to use an aluminum foil with a thickness of 20 to 100 μm. Thereby, a heat-sealable member with suppressed breakage can be easily formed. When using a composite film, it is preferable that the metal layer contains aluminum and the other layer (resin layer) contains a polyamide resin, a polyester resin, etc. Further, when manufacturing the heat-sealable member shown in FIG. 2 without using a composite film, that is, when adopting the method of (5) above, it is preferable to use a film containing a polyamide resin, a polyester resin, etc. as the film for forming the other layer 14.

[0114] As the heat-sealable resin film, a polyolefin resin film, a polyamide resin film, a polyester resin film, etc. can be used. These resin films can be films obtained by a film-forming method such as an extrusion method, a cast molding method, a T-die method, and an inflation method. The thickness of the heat-sealable resin film is usually 10 to 200 μm. In the present invention, a polyolefin resin film is preferable in that heat-sealing for completing the heat-sealable member and heat-sealing when manufacturing a heat-sealed composite product can be easily performed, and a non-stretched polypropylene film is particularly preferable in that a heat-sealed composite product such as a sealed container that is not easily damaged and has excellent durability can be obtained. When using this non-stretched polypropylene film, the preferable thickness is 10 to 200 μm, more preferably 20 to 100 μm.

[0115] The adhesive composition can be applied by a conventionally known method. For example, it can be applied using a bar coater, a gravure coater, etc. The thickness of the coating film and its drying temperature are not particularly limited. The drying temperature of the coating film is not particularly limited, and is preferably 30°C to 100°C from the viewpoint of workability.

[0116] As described above, since the dried coating film generally has adhesiveness and adhesivity, two members can be adhered without heating. However, when manufacturing the heat-sealable member of the present invention, a method such as pressure bonding can be applied while heating to a temperature considering the melting point and melt viscosity of the resin component based on the modified polyolefin resin. As the heating conditions and pressure bonding conditions, for example, the temperature is 180 ° C, the pressure is 0.3 MPa, and the pressure bonding time is 2 seconds.

[0117] In addition, the conditions for promoting the crosslinking reaction between the component (A) and the isocyanate compound to complete the heat-sealable member (hereinafter referred to as "aging conditions") are not particularly limited, and are preferably set according to the material of the metal foil, the material of the heat-sealable resin film, the melting temperature, etc., and the composition of the adhesive layer. As the aging conditions, heating at about 40 ° C for about 3 to 7 days may be sufficient, or a polyolefin having an acidic group and / or an acid anhydride group and an ethylenically unsaturated group as the component (A) may be used, and active energy ray curing such as ultraviolet rays and electron beams and heating may be used in combination to shorten the aging time.

[0118] 9. Use The heat-sealable member of the present invention can be used in various industrial product fields in the electrical, automotive, industrial, and other fields.

[0119] Examples of applications in the electrical field include packaging materials for secondary batteries such as lithium-ion batteries and lithium-ion polymer batteries, decoration by attaching decorative sheets, adhesion between metal members and resins, and encapsulation of electronic components in mobile devices, TV casings, and white goods casings.

[0120] Examples of applications in the automotive field include adhesion of exterior materials made of metal members / resins, adhesion of genuine leather, fabrics, instrument panel foam sheets, and decorative sheets to the base material in interior and exterior members such as pillars, moldings, door trims, spoilers, and roofs.

[0121] Examples of applications in the industrial field include adhesion between films of multilayer films such as industrial packaging materials and barrier films.

[0122] Examples of uses in other fields include adhesion of logistics materials, housing building materials, daily sundries, and sports goods.

[0123] Among these, as the use of the heat-sealable member of the present invention, since it has high peel strength at room temperature and high peel strength during heating, excellent adhesiveness, and high electrolyte resistance, it is preferable as a packaging material for lithium-ion batteries.

Examples

[0124] Hereinafter, examples and comparative examples are shown to more specifically explain the present invention.

[0125] 1. Production example 1) Production example 1 〔Production of component (A)〕 Into a twin-screw extruder (L / D = 42, φ = 58 mm), 100 parts by weight of a propylene-ethylene-1-butene copolymer (propylene component 72 mol%, ethylene component 7 mol%, 1-butene component 21 mol%, weight average molecular weight 120,000, Tm = 100 °C), 2.3 parts by weight of maleic anhydride, 4 parts by weight of lauryl methacrylate, and 1.5 parts by weight of 2,5-dimethyl-2,5-di(t-butylperoxy)hexane were charged. The residence time was 10 minutes, and the barrel temperature was 180 °C (from the first barrel to the seventh barrel) for reaction. Degassing was performed at the seventh barrel to remove the remaining unreacted maleic anhydride and lauryl methacrylate, and a reaction product (hereinafter referred to as "component A1") was obtained.

[0126] 2) Production example 2 〔Production of component (A)〕 In a four-necked flask equipped with a stirrer, a cooling tube, and a dropping funnel, 100 parts by weight of a propylene-ethylene copolymer (propylene component: 97 mol%, ethylene component: 3 mol%, weight-average molecular weight: 250,000, Tm = 125 °C) was heated and dissolved in 400 parts by weight of toluene. After that, while maintaining the temperature in the system at 110 °C and stirring, 1 part by weight of dicumyl peroxide was added dropwise, and then a devolatilization treatment was carried out for 1 hour. Next, 1.5 parts by weight of itaconic anhydride, 3 parts by weight of octyl acrylate, and 0.5 part by weight of benzoyl peroxide were each added dropwise over 3 hours, and the reaction was further carried out for 1 hour. After the reaction, the mixture was cooled to room temperature, and then the crude reaction product was poured into a large excess of acetone to remove unreacted itaconic anhydride and octyl acrylate, and a reaction product (hereinafter referred to as "Component A2") was obtained.

[0127] 3) Production example 3 〔Production of Component (A)〕 Into a twin-screw extruder similar to that in Production Example 1, 100 parts by weight of a propylene-ethylene-1-butene copolymer (propylene component: 68 mol%, ethylene component: 8 mol%, 1-butene component: 24 mol%, weight-average molecular weight: 50,000, Tm = 70 °C), 8 parts by weight of itaconic anhydride, 5 parts by weight of tridecyl acrylate, and 2 parts by weight of lauroyl peroxide were charged. The residence time was 10 minutes, and the barrel temperature was 170 °C (from the first barrel to the seventh barrel) for reaction. Degassing was carried out at the seventh barrel to remove the remaining unreacted itaconic anhydride and tridecyl acrylate, and a reaction product (hereinafter referred to as "Component A3") was obtained.

[0128] 2. Evaluation method for reaction product For the reaction products A1 to A3 obtained in Production Examples 1 to 3, according to the method described below, the weight-average molecular weight, melting point, graft amount of acidic group-containing monomer and / or acid anhydride group-containing monomer, and graft amount of long-chain alkyl (meth)acrylate were measured. The results are shown in Table 1.

[0129] (1) Weight-average molecular weight Apparatus: HLC-8220GPC (manufactured by Tosoh Corporation) Column: Two TSKgel GMHXL (manufactured by Tosoh Corporation) Column temperature: 40 °C Eluent: Tetrahydrofuran 1.00 ml / min Detector: RI The molecular weight measured by GPC was converted based on the molecular weight of polystyrene.

[0130] (2) Melting point In accordance with the provisions of JIS K 7121 (established in 1987), measurement was carried out using a differential scanning calorimeter at a heating rate of 10 °C / min, and the crystallization temperature was defined as the melting point (hereinafter referred to as "Tm").

[0131] (3) Graft amount of monomer containing acid anhydride group The graft amount of the acid anhydride group-containing monomer is defined by the following formula from the acid value obtained by the measurement described below. Graft amount (wt%) = acid value × M × 100 / (1000 × 56.1 × V) M = (molecular weight of the acid anhydride group-containing monomer) + (number of unsaturated groups in the acid anhydride group-containing monomer) × 1.008 · In the case of maleic anhydride, M = 99.1 · In the case of aconitic anhydride, M = 157.1 · In the case of itaconic anhydride, M = 113.1 V = valence of the acidic group when the acid anhydride group-containing monomer is hydrolyzed · In the case of maleic anhydride, V = 2 · In the case of aconitic anhydride, V = 3 · In the case of itaconic anhydride, V = 2 The graft amounts of the acid anhydride group-containing monomers of the reactants A1 to A3 were calculated according to the following formula. Graft amount of A1 (wt%) = acid value × 99.1 × 100 / (1000 × 56.1 × 2) Graft amount of A2 (wt%) = acid value × 157.1 × 100 / (1000 × 56.1 × 3) Graft amount of A3 (wt%) = acid value × 113.1 × 100 / (1000 × 56.1 × 2) ◆ Method for measuring acid value The acid value indicates the number of milligrams of potassium hydroxide required to neutralize the acid contained in 1 g of the sample, and was measured in accordance with JIS K 0070:1992. Specifically, 0.2 g of the sample to be measured was precisely weighed into an Erlenmeyer flask with a stopper, 20 ml of tetrahydrofuran was added, and it was dissolved while heating to obtain a sample solution. Next, several drops of a 1 w / v% phenolphthalein ethanol solution were added as an indicator to this sample solution, and titration was performed using a 0.1 mol / L ethanol solution of potassium hydroxide as the titrant until a faint pink color that persisted for 10 seconds was exhibited, and the acid value was calculated according to the following formula. Acid value (mgKOH / g) = (T × F × 56.1 × 0.1) / W Here, in the above calculation formula, T represents the titration volume (mL), F represents the factor of the titrant, and W represents the sample collection amount (g).

[0132] (4) Graft amount of (meth)acrylic acid long-chain alkyl ester First, using a twin-screw extruder similar to that in Production Example 1, a long-chain alkyl (meth)acrylate (concentration (wt%): C1, C2, and C3), which is a raw material for Reactants A1 to A3, was mixed with the polyolefin, which is a raw material for Reactants A1 to A3. After that, using a hot press, three types of films (thickness: 100 μm) with different long-chain alkyl (meth)acrylate concentrations were obtained. By Fourier transform infrared spectroscopy, the infrared absorption spectra of the three types of films were measured, and absorbance ratios Y1, Y2, and Y3 were determined according to the following formula, and a calibration curve for concentrations C1, C2, and C3 was created. Absorbance ratio Y = (Absorbance derived from ester carbonyl stretching vibration (1730 ± 10 cm -1 )) / (Absorbance derived from C-H bending vibration of CH3 (1380 ± 10 cm -1 )) Y1: Y when the concentration is C1 Y2: Y when the concentration is C2 Y3: Y when the concentration is C3 Next, the infrared spectra of Reactants A1 to A3 were measured, and the absorbance ratio Y A1 (Y of Reactant A1), Y A2 (Y of Reactant A2) and Y A3(Y of Reactant A3) was determined, and the grafting amounts of (meth)acrylic acid long-chain alkyl esters of Reactants A1 to A3 were calculated according to the following formula based on the calibration curve. Grafting amount of A1 (wt%) = (Y A1 -b) / a Grafting amount of A2 (wt%) = (Y A2 -b) / a Grafting amount of A3 (wt%) = (Y A3 -b) / a a = (3f - d×e) / (3c - d 2 ) b = (c×e - f×d) / (3c - d 2 ) c = C1 2 + C2 2 + C3 2 d = C1 + C2 + C3 e = Y1 + Y2 + Y3 f = C1Y1 + C2Y2 + C3Y3

[0133]

Table 1

[0134] 3. Examples 1 to 14, Comparative examples 1 to 8 1) Preparation of adhesive composition Into a 300 ml flask equipped with a condenser and a stirrer, the (A) component and the organic solvent shown in Table 2 below were charged, and the mixture was stirred at 60 °C for 10 minutes to obtain a solution. After cooling to room temperature, a reaction accelerator was added to this solution and further mixed to obtain a liquid resin composition. Next, the isocyanate compound (B) component and / or (C) component shown in Table 2 were blended and mixed with the resin composition at the ratios shown in Table 2 to obtain an adhesive composition. In addition, when preparing the test pieces described below, after blending the isocyanate compound, the adhesive composition was used within 1 hour.

[0135] Using the obtained adhesive composition of Table 2, the evaluations described below were conducted. The results are shown in Table 2.

[0136] The numbers in Table 2 represent parts by weight. The abbreviations in Table 2 have the following meanings. · DBTL: Dibutyltin dilaurate, manufactured by ADEKA Corporation, Adeka Stab BT-11 · TPA100: Isocyanurate of hexamethylene diisocyanate (having a hydrocarbon group with 6 carbon atoms), Duranate TPA-100 manufactured by Asahi Kasei Corporation · N3200: Biuret of hexamethylene diisocyanate (having a hydrocarbon group with 6 carbon atoms), Desmodur N3200 manufactured by Sumitomo Bayer Urethane Co., Ltd. · HT: Adduct of hexamethylene diisocyanate (having a hydrocarbon group with 6 carbon atoms) and trimethylolpropane, Sumidur HT manufactured by Sumitomo Bayer Urethane Co., Ltd. · XP2580: Allophanate of hexamethylene diisocyanate (having a hydrocarbon group with 6 carbon atoms), Desmodur XP2580 manufactured by Sumitomo Bayer Urethane Co., Ltd. · HDI: Hexamethylene diisocyanate (having a hydrocarbon group with 6 carbon atoms) · TMDI: Tetramethylene diisocyanate (having a hydrocarbon group with 4 carbon atoms) · Z4470: Isocyanurate of isophorone diisocyanate (having a hydrocarbon group with 10 carbon atoms), Desmodur Z4470 BA manufactured by Sumitomo Bayer Urethane Co., Ltd. · XP2565: Allophanate of isophorone diisocyanate (having a hydrocarbon group with 10 carbon atoms), Desmodur XP2565 manufactured by Sumitomo Bayer Urethane Co., Ltd. · D140N: Adduct of isophorone diisocyanate (having a hydrocarbon group with 10 carbon atoms) and trimethylolpropane, Takenate D-140N manufactured by Mitsui Chemicals, Inc. · EPDC1241: Mono-adduct of isophorone diisocyanate (having a hydrocarbon group with 10 carbon atoms) and hydroxyethyl acrylate, VESTANAT EP-DC1241 manufactured by Evonik Japan Co., Ltd. · IPDI: Isophorone diisocyanate (having a hydrocarbon group with 10 carbon atoms) ·DDDI: Dodecane diisocyanate (having a hydrocarbon group with 12 carbon atoms)

[0137] 2) Evaluation of liquidity of adhesive composition (1) Viscosity Measurement was carried out using a B-type rotational viscometer (manufactured by Toki Sangyo Co., Ltd.) under the condition of a temperature of 25°C ± 0.5°C.

[0138] 3) Preparation of test piece The adhesive composition was applied to an aluminum foil (size: 100 mm × 200 mm, thickness: 40 μm, surface treatment: chemical conversion treatment) using a bar coater, and then dried at 80°C for 60 seconds and further at 180°C for 20 seconds to remove the organic solvent contained in the adhesive composition, thereby forming an adhesive layer with a film thickness of 4 μm. Next, an unstretched polypropylene film (thickness 80 μm, hereinafter referred to as "CPP") as a heat-sealable resin film was laminated on the surface of the adhesive layer, and pressure was applied from the surface of the aluminum foil using a thermal gradient tester to perform pressure bonding. The bonding conditions at this time were a temperature of 180°C, a pressure of 0.3 MPa, and a pressure bonding time of 2 seconds. Thereafter, this integrated product was placed in a hot air circulation oven adjusted to 40°C for 3 days to obtain test pieces.

[0139] 4) Evaluation of test piece Using the test pieces obtained in the above 3.3), the evaluation described below was carried out.

[0140] (1) Adhesiveness [Normal temperature peel strength] The test pieces were cut into a width of 15 mm, and the normal temperature peel strength (measurement temperature 25°C) between the aluminum foil and CPP was measured by a T-peel test (tensile speed 100 mm / min), and evaluation was carried out at the following three levels. The results are shown in Table 2. ◎: 20 N / 15 mm or more 〇: 10 N / 15 mm or more and less than 20 N / 15 mm ×: Less than 10 N / 15 mm [Hot peel strength] The test piece was cut to a width of 15 mm, and the hot peel strength (measurement temperature: 80°C) between the aluminum foil and CPP was measured by a T-peel test (tensile speed: 100 mm / min), and evaluation was performed at the following three levels. The results are shown in Table 2. ◎: 15 N / 15 mm or more 〇: 10 N / 15 mm or more and less than 15 N / 15 mm ×: Less than 10 N / 15 mm

[0141] (2) Electrolyte resistance As the electrolytic solution, ethylene carbonate, diethyl carbonate, and dimethyl carbonate were mixed at a weight ratio of 1:1:1, and lithium hexafluorophosphate was added thereto at a concentration of 1 mol / L. After the test piece was immersed in the electrolytic solution at 80°C for 8 days, the normal temperature peel strength (measurement temperature: 25°C) between the aluminum foil and CPP was measured by a T-peel test (tensile speed: 100 mm / min), and evaluation was performed at the following three levels. The results are shown in Table 2. ◎: 15 N / 15 mm or more 〇: 10 N / 15 mm or more and less than 15 N / 15 mm ×: Less than 10 N / 15 mm

[0142]

Table 2

[0143] 5. Evaluation results As is clear from the results of Examples 1 to 14, the adhesive composition of the present invention has a high normal temperature peel strength of 20 N / 15 mm or more and a high hot peel strength of 10 N / 15 mm or more, is excellent in adhesiveness, and is also excellent in electrolytic solution resistance. On the other hand, the adhesive compositions of Comparative Examples 1 to 8, although containing the (A) component, contain only one of the (B) component or the (C) component as the isocyanate compound, so either the normal temperature peel strength or the hot peel strength is low and the adhesiveness is poor.

Industrial Applicability

[0144] The present invention relates to an adhesive composition and a heat-sealable member using the same, and can be used in various industrial product fields such as the electrical field, the automotive field, and the industrial field, and belongs to these technical fields.

[0145] This application claims priority based on Japanese Patent Application No. 2017-124637 filed on June 26, 2017, and all of its disclosures are incorporated herein.

Claims

1. An adhesive composition containing an organic solvent, a polyolefin (A) having an acid anhydride group dissolved in the organic solvent, an isocyanate compound, and a curing catalyst, wherein the isocyanate compound contains a diisocyanate compound having a hydrocarbon group with 4 to 7 carbon atoms and / or its derivative (B), and a diisocyanate compound having a hydrocarbon group with 8 to 14 carbon atoms and / or its derivative (C), the weight average molecular weight of the polyolefin (A) is 15,000 to 200,000, and the curing catalyst contains an organotin compound.

2. The adhesive composition according to claim 1, wherein the diisocyanate compound having a hydrocarbon group with 4 to 7 carbon atoms is hexamethylene diisocyanate.

3. The adhesive composition according to claim 1 or 2, wherein the diisocyanate compound having a hydrocarbon group with 8 to 14 carbon atoms is a diisocyanate compound having at least one secondary isocyanate group.

4. The adhesive composition according to any one of claims 1 to 3, wherein the diisocyanate compound having a hydrocarbon group with 8 to 14 carbon atoms is isophorone diisocyanate.

5. The adhesive composition according to any one of claims 1 to 4, wherein the derivative of the diisocyanate compound having a hydrocarbon group with 4 to 7 carbon atoms and / or the derivative of the diisocyanate compound having a hydrocarbon group with 8 to 14 carbon atoms contains at least one bond selected from the group consisting of isocyanurate bond, burette bond, urethane bond, and allophanate bond.

6. The adhesive composition according to any one of claims 1 to 5, wherein the total graft amount of the acidic group-containing monomer and the acid anhydride group-containing monomer in the component (A) is 1.2% by weight or more.

7. The adhesive composition according to any one of claims 1 to 6, wherein the component (A) is a polyolefin graft-modified with an esterified product of an alkyl alcohol having 8 to 18 carbon atoms and (meth)acrylic acid, and the graft amount thereof is 0.10 to 20% by weight.

8. A heat-sealable member comprising an adhesive layer formed by curing the adhesive composition according to any one of claims 1 to 7, a metal layer joined to one side of the adhesive layer, and a heat-sealable resin layer joined to the other side of the adhesive layer.

9. A packaging material for a lithium-ion battery, comprising the heat-sealable member according to claim 8.

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