JPWO2018221037A1 - Polyolefin adhesive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive containing an acid-modified polyolefin and a polyfunctional polyisocyanate curing agent, which has good pot life and good adhesion, chemical resistance, and moldability between a metal substrate and a polyolefin resin substrate. It is to provide a composition. An adhesive composition comprising an acid-modified polyolefin (A), a polyfunctional polyisocyanate curing agent (B) and an organic solvent (C), wherein the acid-modified polyolefin (A) has an acid value of 2 to 50 mgKOH. / G-resin, the adhesive composition whose acetone extraction component ratio is 0.01-2 mass%. [Selection diagram] None

Description

  The present invention relates to an adhesive composition exhibiting good adhesion, chemical resistance, and moldability between a polyolefin resin substrate and a metal substrate. More specifically, the present invention relates to an adhesive composition containing an acid-modified polyolefin, a polyfunctional polyisocyanate curing agent, and an organic solvent. In particular, the present invention relates to an adhesive composition for a lithium ion battery (hereinafter abbreviated as LiB) and a packaging material that is a laminate containing the same.

  2. Description of the Related Art In recent years, LiBs that can be made ultrathin and compact have been actively developed as batteries used in personal digital assistants, mobile phones and other portable terminal devices, video cameras, satellites, and the like. Unlike the conventional metal cans, this LiB packaging material has the advantage of being lightweight and allowing the battery shape to be freely selected, so that a laminate having a structure such as a base material layer / barrier layer / sealant layer is used. It is being used.

  LiB is impregnated with an electrolyte or a lithium electrolyte dissolved in an aprotic solvent such as propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate, together with the cathode material and the anode material as battery contents. And an electrolyte layer made of a polymer gel. When such a highly permeable solvent passes through the sealant layer, the lamination strength between the barrier layer and the sealant layer is reduced to cause delamination, which eventually causes a problem that the electrolyte leaks out. LiPF6, LiBF4, and other substances are used as lithium salts, which are electrolytes for batteries. These salts generate hydrofluoric acid by a hydrolysis reaction with moisture, and hydrofluoric acid corrodes the barrier layer. Reduces the laminate strength. It is necessary that the battery packaging material has resistance to the electrolyte as described above.

  Also, LiB needs to have more severe durability, assuming that it will be used in various environments. For example, when used in a mobile device, it is required to have a liquid leakage resistance in a high temperature environment of 60 to 70 ° C. such as in a vehicle. Also, assuming that it is used by a mobile phone and accidentally dropped into water, it is necessary to have water resistance so that moisture does not enter.

  Under such circumstances, various packaging materials for lithium batteries with improved electrolyte resistance have been proposed (for example, see Patent Documents 1 to 3).

Further, in the battery packaging material, when enclosing the battery element, it is molded with a mold to form a space for accommodating the battery element. During this molding, the battery packaging material is stretched,
There is a problem that cracks and pinholes are easily generated in the barrier layer at the flange portion of the mold. In particular, with the recent demand for smaller and thinner batteries, thinner battery packaging materials are required, and such problems are more likely to occur.

  Under such circumstances, packaging materials for batteries with improved moldability have been proposed (for example, see Patent Documents 4 and 5).

JP 2001-243928 A JP-A-2004-42477 JP 2009-238475 A JP 2002-216714 A JP 2003-31188 A

However, the proposed packaging materials for lithium batteries are still insufficient in terms of electrolyte resistance and moldability. Further, even if the improvement in the electrolytic solution resistance and the moldability was large, a problem was observed.
Specifically, it is difficult to ensure both the pot life of the adhesive after the curing agent is compounded and the resistance to the electrolytic solution (Patent Document 1), and the lamination machine base is restricted due to the bonding by extrusion lamination. However, the polyolefin substrate is affected by heat shrinkage due to bonding at a high temperature (Patent Literature 2). Since the polyolefin base is an aqueous material, the drying time is long and the production conditions are limited (Patent Literature 3). In addition, it is necessary to provide a step of coating the amide-based slip agent on the surface of the outer-layer film.In addition to lowering the productivity, the coated amide-based slip agent provides sufficient lamination strength between the outer-layer film and the aluminum foil. No (Patent Literature 4), a configuration in which only an unstretched polypropylene resin film is disposed on the inner layer side of the aluminum foil, or a configuration in which only a blended resin film of polypropylene and polyethylene is disposed on the inner layer side of the aluminum foil, When formed into a rectangular parallelepiped or the like, pinholes are generated in the aluminum foil, or broken portions (cracks) are likely to be generated in the aluminum foil, and sufficient moldability cannot be obtained (Patent Document 5). It was something that could be seen.

  An object of the present invention is to provide an adhesive composition which is excellent in adhesiveness, chemical resistance (electrolyte resistance) and moldability without problems such as pot life and restrictions on production conditions. Another object of the present invention is to provide a battery packaging material including an adhesive layer made of the adhesive composition, and a battery using the packaging material.

  In order to achieve the above object, the present inventors diligently studied and found that it is effective to arrange a layer that can sufficiently follow the elongation during molding not only on the outer layer side but also on the inner layer side of the aluminum foil. The following inventions have been proposed.

  An adhesive composition containing an acid-modified polyolefin (A), a polyfunctional polyisocyanate curing agent (B), and an organic solvent (C), wherein the acid value of the acid-modified polyolefin (A) is 2 to 50 mgKOH / g-resin. And an adhesive composition having an acetone extraction component ratio of 0.01 to 2% by mass.

  It is preferable to contain 0.5 to 40 parts by mass of the polyfunctional polyisocyanate curing agent (B) and 80 to 2,000 parts by mass of the organic solvent (C) based on 100 parts by mass of the acid-modified polyolefin (A). The organic solvent (C) is a mixture of the solvent (C1) and the solvent (C2), and the solvent (C1) is an aromatic hydrocarbon, an aliphatic hydrocarbon, an alicyclic hydrocarbon, and a halogenated hydrocarbon. Wherein the solvent (C2) is one or more solvents selected from the group consisting of alcohol solvents, ketone solvents, ester solvents and glycol ether solvents. , Solvent (C1) / solvent (C2) = 50 to 97/50 to 3 (mass ratio).

  The adhesive composition is preferably used for bonding a polyolefin resin substrate and a metal substrate.

  A laminate of a polyolefin resin substrate and a metal substrate bonded by the adhesive composition, and a packaging material for a lithium ion battery including the laminate as a constituent member.

  The adhesive composition according to the present invention contains an acid-modified polyolefin, a polyfunctional polyisocyanate curing agent, and an organic solvent, and maintains good pot life without thickening or gelling even when stored for a long time. can do. Further, even when the polyolefin substrate is bonded at a low temperature such as 120 ° C. or less where the heat shrinkage effect is small and aging is performed at a low temperature such as 40 ° C. or less, good adhesion between the polyolefin resin substrate and the metal substrate can be obtained. It is possible to achieve both chemical properties and moldability.

  ADVANTAGE OF THE INVENTION According to this invention, while maintaining favorable pot life property, it can fully be hardened by the aging process after bonding, and can exhibit excellent adhesiveness and chemical resistance. Furthermore, it is possible to obtain an adhesive layer that satisfies the storage elastic modulus and elongation at break necessary for exhibiting excellent moldability.

  Hereinafter, embodiments of the present invention will be described in detail.

<Acid-modified polyolefin (A)>
The acid-modified polyolefin (A) used in the present invention is an acid-modified polyolefin having an acid value of 2 to 50 mgKOH / g-resin and an acetone extraction component ratio of 0.01 to 2% by mass.

  The acid-modified polyolefin (A) used in the present invention is not limited, but at least one of polyethylene, polypropylene and propylene-α-olefin copolymer may contain at least one of α, β-unsaturated carboxylic acid and its acid anhydride. Those obtained by grafting one type are preferred.

  The propylene-α-olefin copolymer is obtained by copolymerizing α-olefin with propylene as a main component. As the α-olefin, for example, one or several kinds of ethylene, 1-butene, 1-heptene, 1-octene, 4-methyl-1-pentene, vinyl acetate and the like can be used. Among these α-olefins, ethylene and 1-butene are preferred. The ratio between the propylene component and the α-olefin component of the propylene-α-olefin copolymer is not limited, but the propylene component is preferably at least 50 mol%, more preferably at least 70 mol%.

  Examples of at least one of the α, β-unsaturated carboxylic acids and their acid anhydrides include maleic acid, itaconic acid, citraconic acid and acid anhydrides thereof. Of these, acid anhydrides are preferred, and maleic anhydride is more preferred. Specifically, maleic anhydride-modified polypropylene, maleic anhydride-modified propylene-ethylene copolymer, maleic anhydride-modified propylene-butene copolymer, maleic anhydride-modified propylene-ethylene-butene copolymer, and the like, These acid-modified polyolefins can be used alone or in combination of two or more.

  The acid value of the acid-modified polyolefin (A) needs to be in the range of 2 to 50 mgKOH / g-resin from the viewpoint of the adhesion between the polyolefin resin base and the metal base and the resistance to electrolytic solution. It is preferably in the range of 3 to 45 mg KOH / g-resin, more preferably 5 to 40 mg KOH / g-resin, and particularly preferably 7 to 35 mg KOH / g-resin. If it is less than the above value, the compatibility with the curing agent may be poor. Therefore, the crosslinking density is low, and the adhesive strength and the chemical resistance (electrolyte resistance) may decrease. If the above value is exceeded, the molecular weight is low and the cohesive strength is weak, so that the adhesive strength and chemical resistance (electrolyte resistance) may be reduced. Further, the production efficiency is undesirably reduced.

  The acid value of the acid-modified polyolefin (A) can be adjusted by the amount of the α, β-unsaturated carboxylic acid, the acid anhydride of the α, β-unsaturated carboxylic acid, and the amount of the radical generator used.

  The ratio of the acetone-extracted component of the acid-modified polyolefin (A) must be in the range of 0.01% by mass to 2% by mass from the viewpoint of the adhesion between the polyolefin resin substrate and the metal substrate and the resistance to electrolytic solution. It is. It is preferably from 0.03% by mass to 1.7% by mass, more preferably from 0.05% by mass to 1.4% by mass, even more preferably from 0.07% by mass to 1.2% by mass, Particularly preferably, it is in the range of 0.1% by mass to 1% by mass. If it is less than the above value, the production efficiency is undesirably reduced. If it exceeds the above-mentioned value, the cohesive strength becomes weak, and the adhesiveness, chemical resistance and moldability may be poor.

  The storage elastic modulus (E ′) of the acid-modified polyolefin (A) at 25 ° C. is in the range of 10 to 2000 MPa from the viewpoints of adhesion between the polyolefin resin base and the metal base and chemical resistance (electrolyte resistance). Preferably, there is. It is more preferably 15 to 1700 MPa, further preferably 20 to 1400 MPa, particularly preferably 25 to 1100 MPa, and most preferably 30 to 800 MPa. If it is less than the above-mentioned value, the cohesive strength of the adhesive layer composed of the adhesive composition may be insufficient, and the adhesiveness and chemical resistance (electrolyte resistance) may be poor. When the value exceeds the above-mentioned value, the followability of the adhesive layer composed of the adhesive composition is lowered, and the adhesiveness may be poor. Further, when the content is within the above range, the adhesiveness and the substrate followability are improved, and the moldability of the laminate is improved, so that it is more preferable as a packaging material for a lithium ion battery.

  The tensile elongation at break (Eb) at 25 ° C. of the acid-modified polyolefin (A) is preferably in the range of 50% to 1000%. It is more preferably from 80% to 900%, further preferably from 120% to 800%, particularly preferably from 160% to 700%, and most preferably from 200% to 600%. If it is less than the above-mentioned value, the followability of the adhesive layer made of the adhesive composition is reduced, which may lead to pinholes or the like during molding, resulting in poor moldability. In general, the tensile elongation at break (Eb) and the storage modulus (E ') are contradictory properties. If the value exceeds the above value, the storage modulus (E') becomes low, and the adhesiveness and the electrolytic solution May be inferior. Further, when the content is within the above range, the adhesiveness and the substrate followability are improved, and the moldability of the laminate is improved, so that it is more preferable as a packaging material for a lithium ion battery.

  The weight-average molecular weight (Mw) of the acid-modified polyolefin (A) is preferably in the range of 10,000 to 200,000. It is more preferably in the range of 20,000 to 180,000, further preferably in the range of 30,000 to 160,000, particularly preferably in the range of 40,000 to 140,000, and most preferably in the range of 50 to 140,000. 000 to 110,000. If it is less than the above value, the cohesive strength may be weak and the adhesiveness may be poor. On the other hand, if it exceeds the above-mentioned value, there may be a problem in operability when bonding with low fluidity. It is preferable if it is in the above-mentioned range because the curing reaction with the curing agent is utilized.

  The crystallinity in the acid-modified polyolefin (A) means that the temperature is raised from −100 ° C. to 250 ° C. at a rate of 20 ° C./min using a differential scanning calorimeter (DSC), and a clear melting peak is observed in the temperature rising process. Indicates what is shown.

  Making the acid-modified polyolefin crystalline is advantageous because it has a stronger cohesive force and is more excellent in adhesiveness and chemical resistance than amorphous.

  The melting point (Tm) of the acid-modified polyolefin (A) is preferably in the range of 50C to 120C. It is more preferably in the range of 60 ° C to 100 ° C, most preferably in the range of 70 ° C to 90 ° C. When the value is less than the above value, the cohesive force derived from the crystal becomes weak, and the adhesiveness and chemical resistance may be poor. On the other hand, if the above value is exceeded, the solution stability and the fluidity are low, and there may be a problem in the operability at the time of bonding.

  The heat of fusion (ΔH) of the acid-modified polyolefin (A) is preferably in the range of 1 J / g to 60 J / g. It is more preferably in the range of 3 J / g to 50 J / g, and most preferably in the range of 5 J / g to 40 J / g. When the value is less than the above value, the cohesive force derived from the crystal becomes weak, and the adhesiveness and chemical resistance may be poor. On the other hand, if the above value is exceeded, the solution stability and the fluidity are low, and there may be a problem in the operability at the time of bonding.

  The method for producing the acid-modified polyolefin (A) is not particularly limited, and may be, for example, a radical grafting reaction (that is, a method in which a radical species is generated with respect to a polymer serving as a main chain, the unsaturated carboxylic acid and A reaction for graft-polymerizing an acid anhydride).

  The radical generator is not particularly limited, but it is preferable to use an organic peroxide. The organic peroxide is not particularly limited, but may be di-tert-butylperoxyphthalate, tert-butyl hydroperoxide, dicumyl peroxide, benzoyl peroxide, tert-butylperoxybenzoate, tert-butylperoxy- Peroxides such as 2-ethylhexanoate, tert-butylperoxypivalate, methyl ethyl ketone peroxide, di-tert-butyl peroxide and lauroyl peroxide; azobisisobutyronitrile, azobisisopropionitrile and the like Azonitriles and the like.

<Polyfunctional polyisocyanate curing agent (B)>
The polyfunctional polyisocyanate curing agent (B) used in the present invention is not particularly limited as long as it is a polyisocyanate having two or more isocyanate groups in one molecule, and well-known diisocyanates and compounds derived therefrom are preferably used. be able to.
For example, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, 1,5-naphthalene diisocyanate, hexamethylene diisocyanate, bis (4-isocyanatocyclohexyl) methane, or water And diisocyanates such as added diphenylmethane diisocyanate. Further, a compound derived from the diisocyanate, that is, an isocyanurate form, an adduct form, a biuret form, a uretdione form, an allophanate form of the diisocyanate, a prepolymer having an isocyanate residue (a low polymer obtained from diisocyanate and polyol), or These complexes are exemplified. These may be used alone or in combination of two or more.

  In addition, a compound obtained by reacting a part of the isocyanate compound with a compound having reactivity with an isocyanate group may be used as a polyfunctional isocyanate curing agent. Compounds having reactivity with an isocyanate group include compounds having an amino group such as butylamine, hexylamine, octylamine, 2-ethylhexylamine, dibutylamine, ethylenediamine, benzylamine, and aniline; methanol, ethanol, propanol, and isopropanol. , Butanol, hexanol, octanol, 2-ethylhexyl alcohol, dodecyl alcohol, ethylene glycol, propylene glycol, benzyl alcohol, phenol and other compounds containing a hydroxyl group; allyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, neopentyl Glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, cyclohexane dimethano Compounds having an epoxy group such as rudiglycidyl ether; and compounds containing a carboxylic acid such as acetic acid, butanoic acid, hexanoic acid, octanoic acid, succinic acid, adipic acid, sebacic acid and phthalic acid.

  As the polyfunctional polyisocyanate curing agent (B) used in the present invention, those having an isocyanurate form of the diisocyanate are preferable because of excellent electrolytic solution resistance.

  The amount of the polyfunctional polyisocyanate curing agent (B) used in the present invention is preferably in the range of 0.5 to 40 parts by mass, more preferably 1 to 40 parts by mass, per 100 parts by mass of the acid-modified polyolefin (A). The amount is 35 parts by mass, more preferably 2 to 30 parts by mass, and particularly preferably 3 to 25 parts by mass. If it is less than the above value, a sufficient curing effect cannot be obtained, and the adhesiveness and chemical resistance may be low. If it exceeds the above range, the pot life and the adhesiveness may decrease, and a pinhole may occur during molding due to a decrease in followability. Further, it is not preferable from the viewpoint of cost.

<Organic solvent (C)>
The organic solvent (C) used in the present invention is not particularly limited as long as it can dissolve the acid-modified polyolefin (A) and the polyfunctional polyisocyanate curing agent (B). Specifically, for example, benzene, toluene, xylene and other aromatic hydrocarbons, hexane, heptane, octane, decane and other aliphatic hydrocarbons, cyclohexane, cyclohexene, methylcyclohexane, ethylcyclohexane and other alicyclic hydrocarbons Halogenated hydrocarbons such as trichloroethylene, dichloroethylene, chlorobenzene, and chloroform; alcoholic solvents such as methanol, ethanol, isopropyl alcohol, butanol, pentanol, hexanol, propanediol, and phenol; acetone, methyl isobutyl ketone, and methyl ethyl ketone Ketone solvents such as pentanone, hexanone, cyclohexanone, isophorone, acetophenone, cellsolves such as methylcellsolve and ethylcellsolve, methyl acetate, ethyl acetate, acetic acid Ester solvents such as chill, methyl propionate and butyl formate, ethylene glycol mono-n-butyl ether, ethylene glycol mono-iso-butyl ether, ethylene glycol mono-tert-butyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol mono-iso- Glycol ether solvents such as butyl ether, triethylene glycol mono-n-butyl ether and tetraethylene glycol mono-n-butyl ether can be used, and one or more of these can be used in combination.

  The amount of the organic solvent (C) is preferably in the range of 80 to 2,000 parts by mass based on 100 parts by mass of the acid-modified polyolefin (A). It is more preferably in the range of 90 to 1600 parts by mass, further preferably 100 to 1200 parts by mass, and particularly preferably in the range of 110 to 800 parts by mass. If the amount is less than the above range, the solution state and the pot life may decrease.If the amount exceeds the above range, productivity, production cost, and transport cost of the laminate and the LiB packaging material including the laminate are disadvantageous. There is.

  The organic solvent (C) is selected from the group consisting of aromatic hydrocarbons, aliphatic hydrocarbons, alicyclic hydrocarbons, and halogenated hydrocarbons from the viewpoint of the solution state and pot life of the adhesive composition. A mixed solution of at least one solvent (C1) selected from the group consisting of at least one solvent (C1), an alcohol solvent, a ketone solvent, an ester solvent, and a glycol ether solvent is preferred. The mixing ratio is preferably in a range of solvent (C1) / solvent (C2) = 50 to 97/50 to 3 (mass ratio), more preferably 55 to 95/45 to 5 (mass ratio). Preferably, it is more preferably 60 to 90/40 to 10 (mass ratio), and particularly preferably 70 to 80/30 to 20 (mass ratio). If the ratio is outside the above range, the solution state and pot life of the adhesive composition may decrease. It is particularly preferable that the solvent (C1) is an aromatic hydrocarbon or an alicyclic hydrocarbon, and the solvent (C2) is a ketone solvent.

<Adhesive composition>
The adhesive composition according to the present invention is a mixture of the acid-modified polyolefin (A), the polyfunctional polyisocyanate curing agent (B) and the organic solvent (C), and comprises an acid-modified polyolefin (A) and a curing agent (B). May be dissolved or dispersed in the organic solvent (C). It is preferably dissolved from the viewpoint of pot life.

  The adhesive composition according to the present invention provides various tackifiers in addition to the acid-modified polyolefin (A), the polyfunctional polyisocyanate curing agent (B) and the organic solvent (C) as long as the performance of the present invention is not impaired. Agents, thermoplastic elastomers and plasticizers can be used. Examples of the tackifier include, but are not particularly limited to, polyterpene resins, rosin resins, aliphatic petroleum resins, alicyclic petroleum resins, copolymer petroleum resins, and hydrogenated petroleum resins. Further, as the thermoplastic elastomer, styrene-ethylene-butylene-styrene copolymer resin, styrene-based elastomer such as styrene-ethylene-propylene-styrene, ethylene-propylene copolymer resin, ethylene-butene copolymer resin, ethylene-vinyl acetate Olefin-based elastomers such as copolymer resins and ethylene-ethyl acrylate copolymer resins are exemplified. Further, as the plasticizer, preferably, a liquid rubber such as polyisoprene, polybutene, or the like, a process oil, or the like is used. These tackifiers, thermoplastic elastomers and plasticizers may be used alone or in combination of two or more.

  The adhesive composition according to the present invention includes various curing agents in addition to the acid-modified polyolefin (A), the polyfunctional polyisocyanate curing agent (B), and the organic solvent (C) as long as the performance of the invention is not impaired. Can be used in combination. Examples of the curing agent include, but are not particularly limited to, an epoxy resin, a carbodiimide compound, an oxazoline compound, and a coupling agent. Epoxy resins include glycidyl ester types such as glycidyl hexahydrophthalate and glycidyl dimer, alicyclic groups such as triglycidyl isocyanurate, 3,4-epoxycyclohexylmethyl carboxylate, epoxidized polybutadiene, and epoxidized soybean oil. Alternatively, an aliphatic epoxide, a glycidyl ether type epoxy resin, a glycidylamine type epoxy resin, or the like may be used. Further, as the carbodiimide compound, dimethylcarbodiimide, diisopropylcarbodiimide, dicyclohexylcarbodiimide, t-butylisopropylcarbodiimide, diphenylcarbodiimide, monocarbodiimide compounds such as di-β-naphthylcarbodiimide, or aliphatic diisocyanate, aromatic diisocyanate, or alicyclic ring And polycarbodiimide compounds which can be produced by conducting a decarboxylation condensation reaction of an organic diisocyanate such as an aromatic diisocyanate in the presence of a condensation catalyst in the absence of a solvent or an inert solvent. Examples of the oxazoline compound include monooxazoles such as 2-oxazoline, 2-methyl-2-oxazoline, 2-phenyl-2-oxazoline, 2,5-dimethyl-2-oxazoline, and 2,4-diphenyl-2-oxazoline. Oxazoline compound, 2,2 ′-(1,3-phenylene) -bis (2-oxazoline), 2,2 ′-(1,2-ethylene) -bis (2-oxazoline), 2,2 ′-(1 And dioxazoline compounds such as 2,4-butylene) -bis (2-oxazoline) and 2,2 ′-(1,4-phenylene) -bis (2-oxazoline). Examples of the coupling agent include a silane coupling agent and a titanate coupling agent.

  The adhesive composition according to the present invention may further comprise a curing accelerator in addition to the acid-modified polyolefin (A), the polyfunctional polyisocyanate curing agent (B), and the organic solvent (C) as long as the performance of the invention is not impaired. Can be used in combination. Examples of the curing accelerator include, but are not particularly limited to, carboxylic acid metal salts, tertiary amines, quaternary ammonium salts, organic peroxides, hydrazine compounds, metal chelate compounds, phosphorus-containing compounds, and basic vulcanizing agents. No. Examples of the carboxylic acid metal salt include a metal salt of a carboxylic acid having 1 to 30 carbon atoms. Examples of the carboxylic acid constituting the metal carboxylate include acetic acid, butyric acid, octanoic acid, decanoic acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, behenic acid, octenoic acid, erucic acid, and elaidin. Aliphatic carboxylic acids such as acid, adipic acid, malonic acid, succinic acid, glutaric acid, citric acid, tartaric acid, malic acid, diglycolic acid; benzoic acid, chlorobenzoic acid, anisic acid, aminobenzoic acid, phthalic acid, terephthalic acid Aromatic carboxylic acids such as acid, naphthoic acid, naphthalenedicarboxylic acid, and benzenetricarboxylic acid; naphthenic acid; and acetone acid. Examples of the metal constituting the metal carboxylate include Li, Na, K, Mg, Ca, Zn, Al, Cu, Pb, Co, Fe, Mn, Sn, and Ti. Specific examples of the metal carboxylate include lithium acetate, sodium acetate, magnesium acetate, aluminum acetate, potassium butyrate, calcium butyrate, zinc butyrate, sodium octanoate, calcium octanoate, potassium decanoate, magnesium decanoate, and decane. Zincate, lithium laurate, sodium laurate, calcium laurate, aluminum laurate, potassium myristate, sodium myristate, aluminum myristate, sodium palmitate, zinc palmitate, magnesium palmitate, sodium stearate, potassium stearate, Calcium stearate, zinc stearate, sodium oleate, sodium behenate, sodium benzoate, zinc benzoate, sodium phthalate, phthalic acid Minium, magnesium terephthalate, calcium naphthalenedicarboxylate, dibutyltin laurate, tributyltin laurate, dioctyltin laurate, tributyltin acetate, dibutyltin diacetate, dioctyltin diacetate, dibutyltin 2-ethylhexoate, tetrabutyl titanate, tetraisobutyl Titanate, tetra-2-ethylhexyl titanate, cobalt naphthenate, copper naphthenate, magnesium naphthenate, cobalt acetoacetate, and the like. Among these, lithium laurate, sodium laurate, calcium laurate, aluminum laurate, potassium myristate, sodium myristate, aluminum myristate, sodium palmitate, zinc palmitate, magnesium palmitate, sodium stearate are preferred. Examples include potassium stearate, calcium stearate, zinc stearate, and sodium oleate. Further, as the carboxylic acid metal salt, a polymer having a carboxylic acid metal salt structure can also be used. As such a polymer, ethylene is used in combination with a metal (eg, Li, Na, K, Mg, Ca, Zn, Al, etc.) salt of a group IA, IIA, IIB, or IIIB of a radically polymerizable carboxylic acid. Those having a polymerized structure; those having a structure in which ethylene and a metal salt of a radically polymerizable carboxylic acid and another radically polymerizable carboxylic acid and / or a derivative thereof are multi-component copolymerized; The tertiary amines include, for example, dimethylaniline, triethanolamine, dimethyl-p-toluidine and the like. Examples of the hydrazine compound include 1-acetyl-2-phenylhydrazine. Examples of the metal chelate compound include vanadium acetylacetonate. Examples of the phosphorus-containing compound include dimethylphosphine and triphenylphosphine. Examples of the basic vulcanizing agents include hexamethylenetetraamine and n-butyraldehyde-aniline condensate.

  The adhesive composition according to the present invention contains various additives in addition to the acid-modified polyolefin (A), the polyfunctional polyisocyanate curing agent (B), and the organic solvent (C) as long as the performance of the present invention is not impaired. It can be used in combination. The additive is not particularly limited, but it is preferable to use a flame retardant, a pigment, an anti-blocking agent and the like.

<Laminate>
The laminate of the present invention is obtained by laminating a polyolefin resin base and a metal base with the adhesive composition according to the present invention.

As a method of laminating, a conventionally known laminate manufacturing technique can be used. For example, although not particularly limited, the adhesive composition is applied to the surface of the metal substrate by using an appropriate application means such as a roll coater or a bar coater, and dried. After drying, while the layer of the adhesive composition (adhesive layer) formed on the surface of the metal substrate is in a molten state, the polyolefin resin substrate is laminated and adhered (laminated) to the application surface to form a laminate. Obtainable.
The thickness of the adhesive layer formed by the adhesive composition is not particularly limited, but is preferably 0.5 to 10 μm, more preferably 0.8 to 9.5 μm, and more preferably 1 to 9 μm. More preferably,

<Polyolefin resin substrate>
The polyolefin resin substrate may be appropriately selected from conventionally known polyolefin resins. For example, although not particularly limited, polyethylene, polypropylene, ethylene-propylene copolymer and the like can be used. Among them, use of a non-stretched polypropylene film (hereinafter, also referred to as CPP) is preferable. The thickness is not particularly limited, but is preferably 20 to 100 μm, more preferably 25 to 95 μm, and further preferably 30 to 90 μm. The polyolefin resin base material may be mixed with a pigment or various additives as necessary, or may be subjected to a surface treatment.

<Metal base material>
Although it does not specifically limit as a metal base material, For example, various metals, such as aluminum, copper, steel, chromium, zinc, duralumin, and die casting, and alloys thereof can be used. In addition, any shape such as a metal foil, a rolled steel plate, a panel, a pipe, a can, and a cap can be used. Generally, aluminum foil is preferred from the viewpoint of workability and the like. Further, although it varies depending on the purpose of use, it is generally used in the form of a sheet having a thickness of 0.01 to 10 mm, preferably 0.02 to 5 mm.
The surface of these metal substrates may be subjected to a surface treatment in advance, or may be left untreated. In any case, the same effect can be exhibited.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the embodiments. In the examples and comparative examples, “parts” simply indicates parts by mass.

<Production example of acid-modified polyolefin (A)>
Production Example 1
In a 1 L autoclave, 100 parts by mass of a propylene-ethylene copolymer (storage modulus at 25 ° C., 320 MPa, tensile elongation at break at 750%: 760%), 233 parts by mass of toluene and 1 part by mass of maleic anhydride, di-tert-butyl After 0.5 part by mass of peroxide was added and the temperature was raised to 140 ° C., the mixture was further stirred for 1 hour (here, it was referred to as “reacted” for 1 hour). Thereafter, the obtained reaction solution was cooled to 100 ° C., and then poured with stirring into a container containing 717 parts by mass of toluene and 950 parts by mass of methyl ethyl ketone, which had been previously heated to 40 ° C., cooled to 40 ° C., and further stirred for 30 minutes. Then, the resin was precipitated by further cooling to 25 ° C. (Here, an operation of pouring the reaction solution into a solvent such as methyl ethyl ketone with stirring and cooling to precipitate the resin is referred to as “reprecipitation”). Thereafter, the slurry liquid containing the resin was centrifuged to separate an acid-modified propylene-ethylene copolymer on which maleic anhydride was graft-polymerized from (poly) maleic anhydride and a low molecular weight product.
Further, the acid-modified propylene-ethylene copolymer taken out by centrifugation was charged with stirring into a new container of 2,000 parts by mass of methyl ethyl ketone kept at 25 ° C. in advance, and stirring was continued for 1 hour. Thereafter, the slurry liquid was centrifuged to further separate the acid-modified propylene-ethylene copolymer from (poly) maleic anhydride and a low molecular weight product. This operation was repeated twice to purify (here, the acid-modified propylene-ethylene copolymer taken out by centrifugation was added to methyl ethyl ketone while stirring, and centrifuged again to strengthen the purification. Is referred to as “reslurry”).
After purification, the polymer was dried under reduced pressure at 70 ° C. for 5 hours to obtain a maleic anhydride-modified propylene-ethylene copolymer (PO-1, acid value 2 mgKOH / g-resin, acetone extraction component ratio 0.1), which is an acid-modified polyolefin. Mass%, storage elastic modulus at 25 ° C of 300 MPa, tensile elongation at break of 600% at 25 ° C, weight average molecular weight of 190,000, Tm of 88 ° C, and ΔH37J / g).

Production Example 2
The acid modification was performed in the same manner as in Production Example 1 except that the charged amount of maleic anhydride was changed to 3 parts by mass, the number of reslurries was changed to 1, and the amount of methyl ethyl ketone to be charged at the time of reslurry was changed to 1000 parts by mass. Polyolefin maleic anhydride-modified propylene-ethylene copolymer (PO-2, acid value 5 mg KOH / g-resin, acetone extraction component ratio 1.8 mass%, storage elastic modulus 280 MPa at 25 ° C., tensile elongation at break at 25 ° C.) Degree 650%, weight average molecular weight 180,000, Tm 88 ° C, ΔH36J / g).

Production Example 3
150 parts by weight of toluene, 40 parts by weight of maleic anhydride, 8 parts by weight of di-tert-butyl peroxide, 3 hours of reaction time, and 700 parts by weight of a solvent used for reprecipitation using methyl ethyl ketone. Parts, the number of reslurries was changed to 5 times, and the same procedure as in Production Example 1 was carried out to obtain a maleic anhydride-modified propylene-ethylene copolymer (PO-3, acid value 48 mg KOH / g-resin, an acid-modified polyolefin). An acetone extraction component ratio of 0.1% by mass, a storage elastic modulus at 25 ° C of 180 MPa, a tensile elongation at break of 350% at 25 ° C, a weight average molecular weight of 31,000, a Tm of 85 ° C, and ΔH31J / g) were obtained.

Production Example 4
150 parts by weight of toluene, 40 parts by weight of maleic anhydride, 8 parts by weight of di-tert-butyl peroxide, 3 hours of reaction time, and 700 parts by weight of a solvent used for reprecipitation using methyl ethyl ketone. Parts, the solvent used for the reslurry was changed to 1,000 parts by mass of methyl ethyl ketone, and the number of reslurries was changed to three times, thereby producing a maleic anhydride-modified propylene-ethylene copolymer (PO- 4, acid value 48mgKOH / g-resin, acetone extraction component ratio 1.8% by mass, storage elastic modulus at 25 ° C 150 MPa, tensile elongation at break 300% at 25 ° C, weight average molecular weight 27,000, Tm 85 ° C, ΔH30J / G).

Production Example 5
The amount of toluene was 150 parts by mass, the amount of maleic anhydride was 20 parts by mass, the amount of di-tert-butyl peroxide was 6 parts by mass, the reaction time was 3 hours, and the solvent used for reprecipitation was 700 parts by mass of methyl ethyl ketone. Parts, the solvent used for the reslurry was changed to 1,000 parts by mass of methyl ethyl ketone, and the number of reslurries was changed to two times to produce a maleic anhydride-modified propylene-ethylene copolymer (PO- 5, acid value 25mgKOH / g-resin, acetone extraction component ratio 0.9 mass%, storage elastic modulus at 25 ° C 400 MPa, tensile elongation at break 500% at 25 ° C, weight average molecular weight 60,000, Tm87 ° C, ΔH35J / G).

Production Example 6
100 parts by mass of a propylene-ethylene copolymer (storage modulus at 25 ° C., 52 MPa, tensile elongation at break at 25 ° C., 1050%), 150 parts by mass of toluene, 30 parts by mass of maleic anhydride, The charged amount of di-tert-butyl peroxide was changed to 6 parts by mass, the reaction time was changed to 3 hours, the solvent used for reprecipitation was changed to 700 parts by mass of methyl ethyl ketone, the solvent used for reslurry was changed to 1000 parts by mass of methyl ethyl ketone, and the number of reslurries was changed to twice. Except for the above, the same procedure as in Production Example 1 was carried out to obtain a maleic anhydride-modified propylene-ethylene copolymer (PO-6, acid value 25 mgKOH / g-resin, an acetone extraction component ratio of 1.0% by mass, which is an acid-modified polyolefin) Storage elastic modulus at 25 ° C 12 MPa, tensile elongation at break 900% at 25 ° C, weight average molecular weight 0,000, Tm58 ℃, △ H7J / g) was obtained.

Production Example 7
100 parts by mass of a propylene homopolymer (storage elastic modulus at 25 ° C., 2100 MPa, tensile elongation at break at 25 ° C .: 900%), 150 parts by mass of toluene, 30 parts by mass of maleic anhydride, Except that the charged amount of tert-butyl peroxide was 6 parts by mass, the reaction time was 3 hours, the solvent used for reprecipitation was 700 parts by mass of methyl ethyl ketone, the solvent used for reslurry was 1000 parts by mass of methyl ethyl ketone, and the number of reslurries was changed to twice. In the same manner as in Production Example 1, a maleic anhydride-modified propylene homopolymer (PO-7, acid value 25 mgKOH / g-resin, an acetone-extracting component ratio of 0.9% by mass, storage at 25 ° C.) was used as an acid-modified polyolefin. Modulus of elasticity 1800MPa, tensile elongation at break at 25 ° C 60%, weight average molecular weight 60,000 Tm85 ℃, to obtain a △ H5J / g).

Production Example 8
100 parts by mass of a propylene-ethylene copolymer (a storage elastic modulus at 25 ° C. of 2,720 MPa and a tensile elongation at break of 400% at 25 ° C.), a charged amount of toluene of 186 parts by mass, and a charged amount of maleic anhydride of 20 parts by mass. The charged amount of di-tert-butyl peroxide was changed to 6 parts by mass, the reaction time was changed to 3 hours, the solvent used for reprecipitation was changed to 700 parts by mass of methyl ethyl ketone, the solvent used for reslurry was changed to 1000 parts by mass of methyl ethyl ketone, and the number of reslurries was changed to twice. Except for the above, the same procedure as in Production Example 1 was carried out to produce a maleic anhydride-modified propylene-ethylene copolymer (PO-8, acid value 25 mgKOH / g-resin, an acetone extraction component ratio of 1.0% by mass, which is an acid-modified polyolefin) Storage elastic modulus at 25 ° C 2350 MPa, tensile elongation at break 38% at 25 ° C, weight average The amount 60,000, Tm125 ℃, △ H63J / g) was obtained.

Production Example 9
The charged amount of toluene was 186 parts by weight, the charged amount of maleic anhydride was 20 parts by weight, the charged amount of di-tert-butyl peroxide was 6 parts by weight, the reaction time was 3 hours, and the solvent used for reprecipitation was 1200 parts by weight of methyl ethyl ketone. Parts, the solvent used for the reslurry was changed to 1200 parts by mass of methyl ethyl ketone, and the number of reslurries was changed to two times to produce a maleic anhydride-modified propylene-ethylene copolymer (PO- 9, acid value 25 mg KOH / g-resin, acetone extraction component ratio 1.2 mass%, storage elastic modulus 7 MPa at 25 ° C, tensile elongation at break 1200% at 25 ° C, weight average molecular weight 60,000, no Tm peak, Δ H0J / g).

Production Example 10
100 parts by mass of a propylene-ethylene copolymer (storage elastic modulus at 25 ° C .: 500 MPa, tensile elongation at break at 680%: 680%), 150 parts by mass of toluene, and 0.5 parts by mass of maleic anhydride Parts, the amount of di-tert-butyl peroxide charged was 0.2 parts by mass, the reaction time was 1 hour, the solvent used for reprecipitation was 1000 parts by mass of methyl ethyl ketone, the solvent used for reslurry was 1000 parts by mass of methyl ethyl ketone, and the number of reslurries was 2 The same procedure as in Production Example 1 was carried out except that the number of times was changed to the number of times, whereby a maleic anhydride-modified propylene-ethylene copolymer (PO-10, an acid value of 1 mg KOH / g-resin, an acetone extraction component ratio of 0.1) was used as an acid-modified polyolefin. 1% by mass, storage modulus at 25 ° C of 400 MPa, tensile elongation at break of 600% at 25 ° C, weight Average molecular weight 65,000, Tm71 ℃, △ H35J / g) was obtained.

Production Example 11
The charged amount of toluene was 150 parts by weight, the charged amount of maleic anhydride was 50 parts by weight, the charged amount of di-tert-butyl peroxide was 10 parts by weight, the reaction time was 3 hours, and the solvent used for reprecipitation was 700 parts by weight of methyl ethyl ketone. Parts, the solvent used for the reslurry was changed to 1,000 parts by mass of methyl ethyl ketone, and the number of reslurries was changed to three times, thereby producing a maleic anhydride-modified propylene-ethylene copolymer (PO- 11, acid value 55 mgKOH / g-resin, acetone extraction component ratio 1.0 mass%, storage elastic modulus at 25 ° C 150 MPa, tensile elongation at break 320% at 25 ° C, weight average molecular weight 30,000, Tm83 ° C, ΔH25J / G).

Production Example 12
Except that the charged amount of toluene was 150 parts by weight, the charged amount of maleic anhydride was 40 parts by weight, the charged amount of di-tert-butyl peroxide was 8 parts by weight, the reaction time was 3 hours, and the number of reslurries was changed to 3 times. In the same manner as in Production Example 1, a maleic anhydride-modified propylene-ethylene copolymer (PO-12, acid value: 46 mgKOH / g-resin, an acetone-extractable component ratio of 4.5% by mass, 25 ° C.) was used as an acid-modified polyolefin. , A tensile elongation at break of 90% at 25 ° C, a weight average molecular weight of 35,000, a Tm of 86 ° C, and ΔH30J / g).

(Preparation of main agent 1)
In a 500 ml four-necked flask equipped with a water-cooled reflux condenser and a stirrer, 100 parts by mass of the maleic anhydride-modified propylene-ethylene copolymer (PO-1) obtained in Production Example 1 and 280 parts by mass of methylcyclohexane And 120 parts by mass of methyl ethyl ketone were charged, the temperature was raised to 80 ° C. with stirring, stirring was continued for 1 hour, and then the mixture was cooled to obtain a main agent 1. Table 1 shows the solution state.

(Preparation of main agents 2 to 19)
The acid-modified polyolefin and the organic solvent were changed as shown in Table 1, and main agents 2 to 19 were produced in the same manner as in main agent 1. Table 1 shows the compounding amount and the solution state.

Example 1
500 parts by mass of the main agent 1 and 1 part by mass of Sumidur (registered trade table) N-3300 as a polyfunctional polyisocyanate curing agent (B) were blended to obtain an adhesive composition. Table 2 shows the evaluation results of the pot life, adhesion, chemical resistance, and moldability.

Examples 2 to 21, Comparative Examples 1 to 3
The main agents 1 to 19 and the respective curing agents were changed as shown in Tables 2 and 3, and Examples 2 to 21 and Comparative Examples 1 to 3 were carried out in the same manner as in Example 1. Tables 2 and 3 show the results of the compounding amount, pot life, adhesion, chemical resistance and moldability.

The curing agents used in Tables 2 and 3 are as follows.
<Polyfunctional polyisocyanate curing agent (B)>
Isocyanurate of hexamethylene diisocyanate: Sumidur (registered trademark) N-3300 (manufactured by Bayer)
Biuret of hexamethylene diisocyanate: Duranate (registered trademark) 24A-100 (manufactured by Asahi Kasei Chemicals Corporation)

Analytical measurement and evaluation were performed on each of the acid-modified polyolefin, main agent, and adhesive composition obtained as described above based on the following methods.
Measurement of Acid Value The acid value (mg KOH / g-resin) in the present invention is the amount of KOH required to neutralize 1 g of acid-modified polyolefin (A), and is a test method according to JIS K0070 (1992). It measured according to. Specifically, after dissolving 1 g of the acid-modified polyolefin in 100 g of xylene adjusted to a temperature of 100 ° C., a 0.1 mol / L potassium hydroxide ethanol solution [trade name “0” using phenolphthalein as an indicator at the same temperature. .1 mol / L ethanolic potassium hydroxide solution ", manufactured by Wako Pure Chemical Industries, Ltd.]. At this time, the acid value (mgKOH / g) was calculated by converting the amount of potassium hydroxide required for the titration into mg.

Measurement of Acetone Extraction Component Ratio The acetone extraction component ratio in the present invention was measured by refluxing with acetone for 2 hours using a Soxhlet extractor. Specifically, 50 g of the acid-modified polyolefin (A) was weighed into a cylindrical filter paper, placed in a Soxhlet extraction tube, and then assembled with a flat-bottomed flask containing 1100 mL of acetone and a cooling tube, and assembled in a water bath. Acetone extraction was performed by refluxing for 2 hours. Thereafter, the cylindrical filter paper was taken out, the acetone extract in the flat-bottomed flask was distilled off, and the residue after drying under reduced pressure at 100 ° C. for 1 hour was weighed, and the value was calculated by the following equation.
Acetone extraction component ratio (% by mass) = (weight of extraction residue / sampled amount) × 100

Measurement of Storage Elastic Modulus (E ') at 25 ° C The storage elastic modulus (E') in the present invention was measured according to the test method of JIS K7244-4 (1999). Specifically, it is a value measured using a dynamic viscoelasticity measuring device DVA-200 manufactured by IT Measurement Control Co., Ltd. at a frequency of 10 Hz while increasing the temperature from -50 ° C at a rate of 5 ° C / min. .

Measurement of tensile elongation at break (Eb) at 25 ° C. The tensile elongation at break (Eb) in the present invention was measured according to the test method of JIS K7161 (2014). Specifically, it is a value obtained by measuring the elongation (%) at the time of breaking at a tension of 50 mm / min in a 25 ° C. environment under a 25 ° C. environment using Tensilon RTM-100 manufactured by Orientec Corporation.

Measurement of weight average molecular weight (Mw) The weight average molecular weight in the present invention is determined by gel permeation chromatograph Alliance e2695 manufactured by Nippon Waters (hereinafter, GPC, standard substance: polystyrene resin, mobile phase: tetrahydrofuran, column: Shodex KF-806 + KF). -803, column temperature: 40 ° C., flow rate: 1.0 ml / min, detector: value measured by a photodiode array detector (wavelength 254 nm = ultraviolet light).

Measurement of melting point and heat of fusion The melting point and heat of fusion in the present invention are increased at a rate of 20 ° C./min using a differential scanning calorimeter (hereinafter, DSC, manufactured by TA Instruments Japan, Q-2000). It is a value measured from the top temperature and the area of the melting peak when the resin is heated and melted, cooled and then heated again.

Evaluation of Main Agent Solution State For the solution state of the main agents 1 to 19, measuring the solution viscosity at 25 ° C. using a Brookfield viscometer TVB-10M (hereinafter also referred to as a B-type viscometer) manufactured by Toki Sangyo Co., Ltd. Was evaluated.
<Evaluation criteria>
◎ (excellent in practical use): less than 500 mPa · s ○ (practicable): 500 mPa · s or more and less than 1000 mPa · s × (impractical): 1000 mPa · s or more or viscosity measurement impossible due to gelation

Evaluation of Pot Life Pot life refers to the stability of a solution obtained by mixing a crosslinking agent or a curing agent with an acid-modified polyolefin and immediately after the compounding or after a certain period of time from the compounding. If the pot life property is good, it means that the solution has a small increase in viscosity and can be stored for a long period of time. If the pot life property is poor, the viscosity of the solution increases (thickness), and if it is severe, This indicates that gelation occurs, making it difficult to apply the composition to a base material and making it impossible to store for a long period of time.
The pot life of the adhesive compositions obtained in Examples 1 to 21 and Comparative Examples 1 to 3 was stored at 25 ° C and 40 ° C for 24 hours, and then the solution viscosity was measured at 25 ° C using a B-type viscometer. Was evaluated by measuring. The evaluation results are shown in Tables 2 and 3.
<Evaluation criteria>
◎ (excellent in practical use): less than 500 mPa · s ○ (practicable): 500 mPa · s or more and less than 1000 mPa · s × (impractical): 1000 mPa · s or more or viscosity measurement impossible due to gelation

Preparation of a laminate of a metal substrate and a polyolefin resin substrate An aluminum foil (8079-0, 40 μm thick, manufactured by Sumi Light Aluminum Foil Co., Ltd.) was used as the metal substrate, and unstretched polypropylene was used as the polyolefin resin substrate A film (Pyrene (registered trademark) film CT, manufactured by Toyobo Co., Ltd., thickness: 40 μm) (hereinafter, also referred to as CPP) was used.
The adhesive compositions obtained in Examples 1 to 19 and Comparative Examples 1 to 15 were applied to a metal substrate by using a bar coater so that the thickness of the dried adhesive layer was 3 μm. The coated surface was dried in a 100 ° C. atmosphere for 1 minute using a warm air drier to obtain a metal substrate on which an adhesive layer having a thickness of 3 μm was laminated. A polyolefin resin substrate is superimposed on the surface of the adhesive layer, and using a small table-top test laminator (SA-1010-S) manufactured by Tester Sangyo Co., at a lamination temperature of 80 ° C. or 120 ° C., 0.3 MPa, 1 m / min. And cured at 25 ° C. and 50% RH for 36 hours to obtain a laminate.

  The laminate obtained as described above was evaluated by the following method.

Evaluation of Adhesiveness The laminate was cut into a size of 100 mm × 15 mm, and the adhesiveness was evaluated by a T-type peel test according to the following criteria. The evaluation results are shown in Tables 2 and 3.

<T-type peel test>
Based on the test method of ASTM-D1876-61, the peel strength at a tensile speed of 50 mm / min was measured at 25 ° C. using Tensilon RTM-100 manufactured by Orientec Corporation. The peel strength (N / cm) between the metal substrate and the polyolefin resin substrate was an average of five test values.

<Evaluation criteria>
☆ (Especially excellent in practical use): 8.0 N / cm or more or CPP is broken (hereinafter simply referred to as “broken”). The material fracture means that the metal substrate or CPP is destroyed without delamination occurring at the interface between the metal substrate and the CPP.
◎ (excellent in practical use): 7.5 N / cm or more and less than 8.0 N / cm ○ (practicable): 7.0 N / cm or more and less than 7.5 N / cm × (impractical): less than 7.0 N / cm

Evaluation of chemical resistance
In order to examine the utility of LiB as a packaging material, the chemical resistance (hereinafter, also referred to as electrolyte resistance) was evaluated by an electrolyte test. The laminate was cut into a size of 100 mm × 15 mm, and added to an electrolytic solution [ethylene carbonate / diethyl carbonate / dimethyl carbonate = 1/1/1 (volume ratio) to which lithium hexafluorophosphate was added] at 85 ° C. For one day. Thereafter, the laminate was taken out, washed with ion-exchanged water, wiped off with a paper wiper, dried sufficiently, and evaluated for chemical resistance by a T-type peel test according to the following criteria. The evaluation results are shown in Tables 2 and 3.

<Evaluation criteria>
☆ (excellent in practical use): 8.0 N / cm or more or material breakage ◎ (excellent in practical use): 7.5 N / cm or more and less than 8.0 N / cm ○ (practicable): 7.0 N / cm or more Less than 5 N / cm × (impractical): less than 7.0 N / cm

Evaluation of formability Similarly, in order to examine the utility of LiB as a packaging material, the formability was evaluated by a deep drawing tester.
The laminate was cut into a size of 80 × 120 mm and cold-formed. Specifically, an overhang molding machine (product number: TP-25C-X2) manufactured by Amada Co., Ltd., a forming die (female die) having a diameter of 55 mm × 35 mm, and a forming die (male die) corresponding thereto ), Cold forming was performed on 10 samples (laminates) at a holding pressure of 0.4 MPa in a 25 ° C. atmosphere and a forming depth of 0.5 mm from a forming depth of 0.5 mm. Was. Regarding the sample after cold forming, the deepest forming depth at which pinholes and cracks did not occur in all ten samples in wrinkles and aluminum foil was defined as the limit forming depth of the sample. From the limit molding depth, the moldability of the battery packaging material was evaluated according to the following criteria. The evaluation results are shown in Tables 3 and 4.
<Judgment criteria>
☆ (Especially excellent in practical use): Limit forming depth of 6.0 mm or more ◎ (Excellent in practical use): Limit forming depth of 4.0 mm or more and less than 6.0 mm ○ (Practical use): Limit forming depth of 2.0 mm or more 4 Less than 0.0 mm ×: less than 2.0 mm limit forming depth

  The adhesive composition according to the present invention contains an acid-modified polyolefin, a polyfunctional polyisocyanate curing agent and an organic solvent, and maintains a good pot life without causing thickening or gelling even when stored for a long time. In addition, good adhesion between the metal substrate and the polyolefin resin substrate, resistance to electrolytes, and moldability can be achieved at the same time. Therefore, a laminate of a polyolefin resin base material and a metal base material formed from the adhesive composition of the present invention can be used not only in the fields of household electrical appliance outer panels, furniture materials, architectural interior members, and the like, but also in personal computers and mobile phones. It can be widely used as a packaging material (pouch type) for lithium batteries used in video cameras and the like.

Claims (6)

  An adhesive composition containing an acid-modified polyolefin (A), a polyfunctional polyisocyanate curing agent (B), and an organic solvent (C), wherein the acid value of the acid-modified polyolefin (A) is 2 to 50 mgKOH / g-resin. And an adhesive composition having an acetone extraction component ratio of 0.01 to 2% by mass.   The polyfunctional polyisocyanate curing agent (B) is contained in 0.5 to 40 parts by mass and the organic solvent (C) is contained in 80 to 2,000 parts by mass with respect to 100 parts by mass of the acid-modified polyolefin (A). Adhesive composition.   The organic solvent (C) is a mixture of the solvent (C1) and the solvent (C2), and the solvent (C1) is composed of an aromatic hydrocarbon, an aliphatic hydrocarbon, an alicyclic hydrocarbon, and a halogenated hydrocarbon. A solvent selected from the group consisting of alcohol solvents, ketone solvents, ester solvents and glycol ether solvents, wherein the solvent (C2) is at least one solvent selected from the group consisting of alcohol solvents, ketone solvents, ester solvents and glycol ether solvents; The adhesive composition according to any one of claims 1 to 2, wherein (C1) / solvent (C2) = 50 to 97/50 to 3 (mass ratio).   The adhesive composition according to any one of claims 1 to 3, which is used for bonding a polyolefin resin substrate and a metal substrate.   A laminate of a polyolefin resin substrate and a metal substrate bonded by the adhesive composition according to claim 1. A packaging material for a lithium ion battery comprising the laminate according to claim 6 as a constituent member.