JP2024044992A - Adhesive composition and laminate - Google Patents

Abstract

To provide an adhesive composition excellent in adhesiveness to metals, moist heat resistance, and heat resistance to a reflow process, and to provide a laminate having a layer comprising the adhesive composition.SOLUTION: The adhesive composition contains 100 pts.mass of a copolyester, 3-13 pts.mass of an epoxy compound, and 0.3-0.9 pt.mass of an imidazole compound. The copolyester contains 30 mol% or more of isophthalic acid in an acid component and contains 30 mol% or more of a glycol having a side chain and 1-20 mol% of a polyalkylene glycol in a glycol component, the polyalkylene glycol having 2-4 carbon atoms in a repeating unit and having a number average molecular weight of 200 or more. The copolyester has an acid value of 2-8 mg KOH/g and a glass transition temperature of -10 to 10°C.SELECTED DRAWING: None

Description

The present invention relates to an adhesive composition and a laminate having layers thereof.

By changing the types and amounts of dicarboxylic acids and glycols that are the constituents of the polyester, it is possible to obtain copolymer polyesters having various characteristics.
Copolymer polyesters generally have excellent adhesive properties to plastics such as polyester, polycarbonate, and polyvinyl chloride, and to metals such as aluminum and copper, and are therefore widely used in adhesives, coating agents, ink binders, paints, and the like.

In addition, copolyester has excellent properties such as electrical insulation, flame retardancy, and flexibility (resistance to peeling at bent parts), so it has been used in digital home appliances and automobiles, which have become thinner and smaller in recent years. It is widely used as an adhesive for flexible flat cables used in industrial parts.

The copolymerized polyester used for the above applications needs to be resistant to heat, as it is affected by heat dissipation from LCD backlights and CPUs, etc. Also, since it may be used outdoors, it must be resistant to high temperatures. It is also required to have heat and humidity resistance so that adhesive properties can be maintained without peeling at the adhesive interface even under humid conditions. For example, Patent Document 1 discloses a polyester that is formed by copolymerizing a specific alkylene glycol and has excellent adhesion to metals and moist heat resistance.

In recent years, as light emitting diodes have become smaller and more sophisticated, the use of LED digital signage has rapidly increased. In particular, flexible printed wiring films are used for transparent LED digital signage because of their light weight and flexibility. The flexible printed wiring film for LED digital signage, which is designed for outdoor use, has adhesion to the metal that forms the wiring and moisture and heat resistance that can withstand long-term outdoor use, as well as the reflow process for surface mounting of LEDs onto the flexible printed wiring film. Heat resistance is required. However, although the adhesive composition described in Patent Document 1 has excellent adhesion to metals and moist heat resistance, and good heat resistance at 80°C, it has poor heat resistance at high temperatures exceeding 200°C such as in a reflow process. had poor performance.

Patent No. 6955768

The object of the present invention is to solve the above problems and provide an adhesive composition that has excellent adhesion to metals, resistance to moist heat, and heat resistance during the reflow process, and a laminate having a layer made of the adhesive composition.

As a result of extensive research to solve the above problems, the present inventors have developed a copolyester consisting of a specific acid component and a glycol component, having a specific acid value and glass transition temperature, and an epoxy compound. The inventors have discovered that a composition containing an imidazole compound can achieve the above object, and have arrived at the present invention.
That is, the gist of the present invention is as follows.

(1) containing 100 parts by mass of copolymerized polyester, 3 to 13 parts by mass of epoxy compound, and 0.3 to 0.9 parts by mass of imidazole compound,
The copolymerized polyester contains 30 mol% or more of isophthalic acid in the acid component, 30 mol% or more of glycol having a side chain in the glycol component, the number of carbon atoms in the repeating unit is 2 to 4, and a number average molecular weight. contains 1 to 20 mol% of polyalkylene glycol having 200 or more,
An adhesive composition characterized in that the copolymerized polyester has an acid value of 2 to 8 mgKOH/g and a glass transition temperature of -10 to 10°C.
(2) A laminate comprising a layer made of the adhesive composition described in (1) above.

According to the present invention, it is possible to provide an adhesive composition that has excellent adhesion to metals, as well as excellent moist heat resistance and heat resistance. A laminate having a layer made of this adhesive composition can be used as a component of flexible printed wiring for LED digital signage and the like.

The adhesive composition of the present invention contains a copolymerized polyester, an epoxy compound, and an imidazole compound. The copolymerized polyester contains isophthalic acid as an acid component, and contains, as glycol components, a glycol having a side chain and a polyalkylene glycol having a carbon number of 2 to 4 in the repeating unit and a number average molecular weight of 200 or more. The adhesive composition has an acid value of 2 to 8 mgKOH/g and a glass transition temperature of -10 to 10°C.
The present invention will be described in detail below.

<Copolymer polyester>
The acid component of the copolymer polyester constituting the adhesive composition of the present invention must contain 30 mol % or more of isophthalic acid, preferably 40 mol % or more, and more preferably 50 to 80 mol %. If the content of isophthalic acid in the acid component is less than 30 mol %, the resulting adhesive composition tends to have reduced adhesion and reduced solubility in organic solvents.

Acid components other than isophthalic acid include terephthalic acid, naphthalene dicarboxylic acid, succinic acid, adipic acid, azelaic acid, sebacic acid, hexahydroterephthalic acid, phthalic acid, 4,4'-dicarboxybiphenyl, 5-sodium sulfoisophthalate. Acid, 5-hydroxyisophthalic acid, fumaric acid, maleic acid, itaconic acid, mesaconic acid, citraconic acid, 1,3,4-benzenetricarboxylic acid, 1,2,4,5-benzenetetracarboxylic acid, oxalic acid, 1 , 3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, tetrahydrophthalic acid, 2,5-norbornenedicarboxylic acid and the like. These may use an anhydride as a monomer raw material, or may be used in combination. Among these, from the viewpoint of maintaining heat resistance, it is preferable to use terephthalic acid, naphthalene dicarboxylic acid, and hexahydroterephthalic acid as acid components other than isophthalic acid.

The glycol component of the copolymerized polyester needs to contain 30 mol% or more of glycol having a side chain, more preferably 40 mol% or more, and even more preferably 50 to 80 mol%. If the content of glycol having a side chain in the glycol component is less than 30 mol %, the resulting adhesive composition tends to have lower adhesive properties and also lower solubility in organic solvents. On the other hand, if the content of glycol having a side chain exceeds 80 mol%, the adhesive composition tends to have lower adhesive properties.
Glycols having side chains include 1,2-propanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 2-methylpropanediol, 3-methyl-1,5-pentanediol, Examples include 2-ethyl-2-butylpropanediol, an ethylene oxide adduct of bisphenol A, a propylene oxide adduct of bisphenol A, and trimethylolpropane, and these may be used in combination. Among them, from the viewpoint of improving adhesion, the glycol having a side chain is preferably 2,2-dimethyl-1,3-propanediol (neopentyl glycol) or an ethylene oxide adduct of bisphenol A.

The glycol component of the copolymerized polyester must contain 1 to 20 mol% of polyalkylene glycol whose repeating unit has 2 to 4 carbon atoms and a number average molecular weight of 200 or more, and 3 to 15 mol%. The content is preferably 4 to 10 mol%, more preferably 4 to 10 mol%. When the content of the polyalkylene glycol in the glycol component of the copolymerized polyester is less than 1 mol %, the moisture and heat resistance of the copolyester decreases. Moreover, the glass transition temperature becomes high, and the resulting adhesive composition may have poor adhesive properties. On the other hand, if the content of the polyalkylene glycol exceeds 20 mol%, the resulting adhesive composition will have poor heat resistance.
The polyalkylene glycol needs to have a number average molecular weight of 200 or more, preferably 500 to 10,000, more preferably 800 to 5,000. By using a polyalkylene glycol with a repeating unit having 2 to 4 carbon atoms and a number average molecular weight of 200 or more, the resulting adhesive composition has improved moist heat resistance.
Polyalkylene glycols whose repeating units have 2 to 4 carbon atoms and a number average molecular weight of 200 or more include polyethylene glycol, polypropylene glycol, polytrimethylene glycol, and polytetramethylene glycol from the viewpoint of adhesiveness and moist heat resistance. is preferred.

Other glycol components include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, etc., and two or more of these may be used in combination.

In addition, other components constituting the copolymerized polyester include lactic acid, glycolic acid, 2-hydroxybutyric acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 2-hydroxyisobutyric acid, 2-hydroxy-2-methylbutyric acid, 2-hydroxybutyric acid, Hydroxy such as hydroxyvaleric acid, 3-hydroxyvaleric acid, 4-hydroxyvaleric acid, 5-hydroxyvaleric acid, 6-hydroxycaproic acid, 10-hydroxystearic acid, 4-(β-hydroxy)ethoxybenzoic acid, malic acid, etc. Examples include carboxylic acids, aliphatic lactones such as β-propiolactone, β-butyrolactone, γ-butyrolactone, δ-valerolactone, and ε-caprolactone, and oxiranes, and these may be contained.

The copolymer polyester may also be copolymerized with monocarboxylic acids and monoalcohols as necessary. Examples of monocarboxylic acids include lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, benzoic acid, p-tert-butylbenzoic acid, cyclohexanoic acid, and 4-hydroxyphenylstearic acid. Examples of monoalcohols include octyl alcohol, decyl alcohol, lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, and 2-phenoxyethanol.

The above-mentioned monomers constituting the copolymerized polyester may be used in combination depending on the properties desired to be imparted.
Further, copolymerized polyesters may be used in combination of two or more types, and may be phase separated or uniformly mixed.

The copolymerized polyester needs to have an acid value of 2 to 8 mgKOH/g, preferably 3 to 7 mgKOH/g, and more preferably 4 to 6 mgKOH/g. When the acid value of the copolyester is within the above range, the resulting adhesive composition will have excellent adhesion to metals and excellent heat resistance. If the acid value is less than 2 mgKOH/g, the copolymerized polyester will have poor heat resistance, and if the acid value exceeds 8 mgKOH/g, the copolymerized polyester will have poor adhesion to metal.

Examples of methods for controlling the acid value of the copolyester include a method of producing a high molecular weight polyester and then adding a depolymerizing agent, a method of adding an acid anhydride, and the like. In the present invention, a method in which a depolymerizing agent is added after producing a high molecular weight polyester is preferred because the acid value can be easily controlled.
As the depolymerizing agent, isophthalic acid, adipic acid, sebacic acid, etc. are preferable, and as the acid anhydride, trimellitic anhydride, pyromellitic anhydride, etc. are preferable.

The copolyester needs to have a glass transition temperature of -10 to 10°C, preferably -8 to 9°C, more preferably -6 to 8°C. When the glass transition temperature of the copolyester is within the above range, the resulting adhesive composition will have excellent adhesion to metals. If the glass transition temperature of the copolyester is lower than -10°C or higher than 10°C, the adhesive composition obtained will have poor adhesion to metal.

The copolymerized polyester preferably has a number average molecular weight of 10,000 to 50,000, more preferably 10,000 to 40,000, and even more preferably 10,000 to 30,000. If the number average molecular weight of the copolyester is less than 10,000, the resulting adhesive composition may have somewhat poor adhesive strength. If the number average molecular weight of the copolyester exceeds 50,000, the adhesive composition may have reduced fluidity and become difficult to apply.

<Epoxy Compound>
The adhesive composition of the present invention must contain an epoxy compound, and the content thereof must be 3 to 13 parts by mass, preferably 3 to 12 parts by mass, and more preferably 4 to 11 parts by mass, relative to 100 parts by mass of the copolymerized polyester. By containing an epoxy compound, the heat resistance of the adhesive composition is improved. If the content of the epoxy compound is less than 3 parts by mass, the heat resistance of the resulting adhesive composition is reduced, whereas if the content exceeds 13 parts by mass, both the heat resistance and the adhesiveness of the resulting adhesive composition are reduced.

The epoxy compound is not particularly limited as long as it is a compound having two or more epoxy groups per molecule. Preferred specific examples include polyethylene glycol, glycerin and its derivatives, compounds with polyhydric hydroxyl groups such as sorbitol in which some of the hydroxyl groups are converted into glycidyl groups, such as sorbitol polyglycidyl ether, glycerol polyglycidyl ether, trimethylolpropane poly Examples include glycidyl ether, diglycerol polyglycidyl ether, and polyglycerol polyglycidyl ether, as well as novolac type epoxy resin, bisphenol type epoxy resin, trisphenolmethane type epoxy resin, amino group-containing epoxy resin, and copolymerized epoxy resin. It will be done. These may be used alone or in combination.

<Imidazole compound>
The adhesive composition of the present invention needs to contain an imidazole compound as a curing accelerator, and the content thereof is 0.3 to 0.9 parts by mass based on 100 parts by mass of copolyester. The amount is preferably from 0.3 to 0.8 parts by weight, more preferably from 0.3 to 0.7 parts by weight. The heat resistance of the adhesive composition is improved by containing the imidazole compound. If the content of the imidazole compound is less than 0.3 parts by mass, the resulting adhesive composition will have reduced heat resistance, while if the content exceeds 0.9 parts by mass, the resulting adhesive composition will have reduced heat resistance. , both heat resistance and adhesion are reduced.

Specific examples of imidazole compounds include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidozolium trimellitate, 2,4-diamino-6-[ 2'-methylimidozolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-undecylimidazolyl-(1')]ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidozolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, and the like. Among these, 2-undecylimidazole, 1-benzyl-2-phenylimidazole, and 1-cyanoethyl-2-undecylimidazole are preferred due to their solubility in the adhesive composition and their stability during high-temperature processing. These may be used alone or in combination.

<Other ingredients in the adhesive composition>
The adhesive composition of the present invention may contain a heat stabilizer, an antioxidant, a flame retardant, etc., if necessary.
Heat stabilizers include phosphoric acid, phosphoric acid esters, dibutyl hydroxytoluene tetrakis[3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionic acid]pentaerythritol, 3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionic acid n-octadecyl, 3,3',3",5,5',5"-hexa-tert-butyl-a,a',a"-(mesitylene-2,4,6 -triyl)tri-p-cresol, 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, 3,9-bis{2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1-dimethylethyl}-2, Examples of the heat stabilizer include phosphorus-based or hindered phenol-based heat stabilizers such as 4,8,10-tetraoxaspiro[5,5]undecane, 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzene)isophthalic acid, triethyl glycol-bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate], 1,6-hexanediol-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2,2-thio-diethylene-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and diethyl[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]phosphate.

Antioxidants include hindered amine compounds, dioctyl thiodipropionate, didodecyl thiodipropionate, didodecyl stearyl thiodipropionate, distearyl thiodipropionate, dimyristyl thiodipropionate, didecyl thiodipropionate, didecyl thiodipropionate, didodecyl-β,β'-thiodibutyrate, distearyl-β,β'-thiodibutyrate, pentaerythritol-tetrakis(dodecyl thiopropionate), pentaerythritol-tetrakis(dodecyl thiopropionate), Examples of antioxidants include pentaerythritol tetrakis (dodecylthioacetate), pentaerythritol tetrakis (dodecylthiobutyrate), pentaerythritol tetrakis (octadecylthiopropionate), pentaerythritol tetrakis (laurylthiopropionate), dilauryl-3,3'-thiodipropionate, distearyl-3,3'-thiodipropionate, ditridecyl 3,3'-thiodipropionate, and tetrakis [methylene-3-(dodecylthio)propionate].

Flame retardants include halides such as decabromodiphenyl ether, bis(pentabromophenyl)ethane, tetrabromobisphenol, hexabromocyclododecane, and hexabromobenzene; phosphorus compounds such as triphenyl phosphate, tricresyl phosphate, 1,3-phenylene bis(diphenyl phosphate), ammonium polyphosphate, polyphosphoric acid amide, and guanidine phosphate; halogen-containing phosphate esters such as tris(chloroethyl)phosphate and tris(dichloropropyl)phosphate; red phosphorus; nitrogen-based flame retardants such as triazine, melamine cyanurate, and ethylenedimelamine; tin dioxide, antimony pentoxide, and antimony trioxide.

In addition, it may contain conventionally known additives such as lubricants such as talc and silica, pigments such as titanium oxide and carbon black, fillers, antistatic agents, and foaming agents.

<Production Method>
Next, a method for producing the adhesive composition of the present invention will be described.
In producing the copolymerized polyester constituting the adhesive composition, the necessary raw materials are charged into a reaction vessel and subjected to an esterification reaction by a known method.
Next, for example, a polycondensation reaction is allowed to proceed under reduced pressure of 130 Pa or less at a temperature of 220 to 280° C. until a desired molecular weight is reached, thereby obtaining a copolymerized polyester. In the esterification reaction and polycondensation reaction, polymerization can be carried out using a titanium compound such as tetrabutyl titanate, a metal acetate such as zinc acetate, magnesium acetate, or zinc acetate, an organic tin compound such as antimony trioxide, hydroxybutyltin oxide, or tin octylate, or an organic sulfonic acid compound such as benzenesulfonic acid. The amount of catalyst used in this case is preferably 0.1 to 20×10 ⁻⁴ mol per 1 mol of the acid component.
Subsequently, after the above-mentioned polycondensation reaction is completed, a predetermined amount of a polybasic acid component or its anhydride or the like is added and reacted to modify the terminal hydroxyl groups to carboxy groups, or to introduce carboxy groups into the middle chains of the molecule by an ester exchange reaction, thereby imparting an appropriate acid value.

Next, the copolymerized polyester is dissolved in a suitable organic solvent to prepare a solution with a solids concentration of about 20 to 60 mass %, and an epoxy compound and an imidazole compound are added to produce a solution of the adhesive composition. The adhesive composition can be obtained by removing the organic solvent from the solution of the adhesive composition.

Examples of organic solvents include aromatic solvents such as toluene, xylene, solvent naphtha, and Solvesso, ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone, and alcohol solvents such as methyl alcohol, ethyl alcohol, isopropyl alcohol, and isobutyl alcohol. Examples include solvents, ester solvents such as ethyl acetate and n-butyl acetate, acetate solvents such as cellosolve acetate and methoxy acetate, and mixed solvents of two or more of these solvents (for example, a mixed solvent of toluene and methyl ethyl ketone). In view of ease of handling, the organic solvent is preferably methyl ethyl ketone, ethyl acetate, or a mixed solvent of toluene and methyl ethyl ketone.

<Laminated body>
The laminate of the present invention has a layer made of an adhesive composition.
As a method for producing a laminate having a layer made of the adhesive composition (hereinafter sometimes abbreviated as adhesive layer) using the adhesive composition of the present invention, the adhesive composition is dissolved in an organic solvent. Examples include a method of applying a dissolved solution (hereinafter sometimes abbreviated as adhesive solution) to a base material such as a film and drying it. As the adhesive solution, a solution prepared by adding an epoxy compound and an imidazole compound to a copolymerized polyester solution in an organic solvent may be used in the production of the adhesive composition described above. In the adhesive solution, the solid content concentration is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 30% by mass or more.
By applying an adhesive solution to a base material using a known coating method and drying it, a laminate in which adhesive layers are laminated can be obtained. As the coater, for example, a bar coater, a comma coater, a die coater, a roll coater, a reverse roll coater, a gravure coater, a gravure reverse coater, a flow coater, etc. can be used. In the coating method using these coaters, the thickness of the adhesive layer can be arbitrarily controlled. Alternatively, the coating may be applied to the substrate using a plurality of coating methods.

The base material is not particularly limited, but includes, for example, those made of resin materials, paper, synthetic paper, cloth, metal materials, glass materials, and the like. The thickness of the base material is also not particularly limited, and can be selected depending on the application and the like.

Examples of resin materials that form the substrate include polyethylene terephthalate, polycarbonate, cycloolefin polymer, polyimide, polyamide, etc. Among these, polyamide is preferred because of its excellent heat resistance and mechanical properties, and in particular, semi-aromatic polyamides that are composed of a dicarboxylic acid component and a diamine component and have an aromatic component in the dicarboxylic acid component or the diamine component are preferred.

The dicarboxylic acid component constituting the semi-aromatic polyamide preferably has terephthalic acid as its main component, and dicarboxylic acid components other than terephthalic acid include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, and sebacic acid. , aliphatic dicarboxylic acids such as dodecanedioic acid, tetradecanedioic acid, and octadecanedioic acid, and aromatic dicarboxylic acids such as 1,4-naphthalene dicarboxylic acid, 1,3-naphthalene dicarboxylic acid, 1,2-naphthalene dicarboxylic acid, and isophthalic acid. Examples include dicarboxylic acids. The proportion of terephthalic acid in the dicarboxylic acid component is preferably 60 to 100 mol%.
Further, the diamine component constituting the semi-aromatic polyamide preferably has an aliphatic diamine having 4 to 15 carbon atoms as a main component. Aliphatic diamines having 4 to 15 carbon atoms include 1,4-butanediamine, 1,5-pentanediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1 , 9-nonanediamine, 2-methyl-1,8-octanediamine, 4-methyl-1,8-octanediamine, 1,10-decanediamine, 1,11-undecanediamine, 1,14-tetradecanediamine, 1, Examples include 15-pentadecanediamine. These may be used alone or in combination of two or more.

As long as the effects of the present invention are not impaired, the base material may include, for example, antioxidants, stabilizers, ultraviolet absorbers, pigments, dyes, antistatic agents, plasticizers, antioxidants, organic or inorganic particles, fillers, It may also contain known additives such as crosslinking agents.

Hereinafter, the present invention will be specifically explained with reference to Examples.
1. Raw materials (1) Raw materials for copolymerized polyester TPA: Terephthalic acid IPA: Isophthalic acid SEA: Sebacic acid TMA: Trimellitic anhydride NPG: Neopentyl glycol EG: Ethylene glycol PTMG: Polytetramethylene glycol (number average molecular weight 1000)
PEG: Polyethylene glycol (number average molecular weight 1000)
DEG: diethylene glycol (molecular weight 106.12)
Hindered phenolic antioxidant: manufactured by BASF Japan, Irganox1010

(2) Epoxy compound: Sorbitol polyglycidyl ether (manufactured by Nagase ChemteX, Denacol EX-614B)
(3) Imidazole compound: 2-undecylimidazole (manufactured by Shikoku Kasei Co., Ltd., C11Z)

2. Evaluation method (1) Composition of copolymer polyester ^1H -NMR measurement was performed using an NMR device (JNM-ECZ400R/S1 type manufactured by JEOL Ltd.), and the composition was determined from the peak intensity of each copolymer component. As the measurement solvent, a mixed solvent of deuterated trifluoroacetic acid and deuterated tetrachloroethane with a volume ratio of 1/11 was used.

(2) Number average molecular weight of copolymerized polyester GPC analyzer (Liquid delivery unit LC-10ADvp type and UV-visible spectrophotometer SPD-6AV type, manufactured by Shimadzu Corporation, detection wavelength: 254 nm, solvent: tetrahydrofuran, polystyrene equivalent) , the number average molecular weight was determined.

(3) Glass transition temperature (Tg) of copolymer polyester
The glass transition temperature (extrapolated glass transition onset temperature) was determined using a power compensation type differential scanning calorimeter (Diamond DSC manufactured by PerkinElmer) in accordance with JIS-K7121.

(4) Acid value of copolymer polyester 150 mg of copolymer polyester was weighed out in a test tube, 5 mL of benzyl alcohol was added, and the mixture was dissolved by heating, and transferred to a Mayer flask containing 10 mL of chloroform. The test tube used was washed by heating with 5 mL of benzyl alcohol, and the washings were also transferred to the Mayer flask. The obtained copolymer polyester solution was titrated with 0.1 N KOH benzyl alcohol solution using phenol red as an indicator, and the acid value (mg KOH/g) of the copolymer polyester was calculated from the difference with the titration amount of the blank test.

(5) Adhesiveness Rolled copper foil (18 μm) was layered on the adhesive composition layer of the laminate obtained in Examples and Comparative Examples, and heated from 30°C in a vacuum press at 1.07 kPa (8 Torr). The temperature was raised to 180°C at a rate of 15°C/min, and the temperature was maintained at 180°C for 60 minutes while applying a pressure of 30 kgf/cm ² . Thereafter, a laminate sheet was obtained by cooling to room temperature. A sample with a width of 15 mm was prepared from the obtained laminate sheet, and a 180 degree peel test was performed at 23° C. and 50 mm/min to measure the peel strength and evaluate the adhesive strength.
○: 14N/15mm or more △: Less than 14N/15mm, 11N/15mm or more ×: Less than 11N/15mm

(6) Moist Heat Resistance The laminate sheet prepared by the method described in (5) Adhesion was subjected to a moist heat treatment by keeping it for 1000 hours under conditions of a temperature of 85°C and a relative humidity of 85% in a thermo-hygrostat (Model LH-30-13M manufactured by Nakatsu Scientific Machinery Works, Ltd.).
A 15 mm wide sample was prepared from the laminate sheet after the moist heat treatment, and a 180° peel test was performed at 23° C. and 50 mm/min to measure the peel strength and evaluate the moist heat resistance. Note that, when the peel strength in (5) above was less than 11 N/15 mm, the moist heat resistance was not evaluated.
○: 10N/15mm or more △: less than 10N/15mm, 8N/15mm or more ×: less than 8N/15mm

(7) Soldering heat resistance A 40 mm x 40 mm sample was prepared from the laminate sheet prepared using the method described in (5) Adhesion above, and the soldering heat resistance was evaluated by immersing the sample in a 260°C solder bath for 60 seconds. did.
○: There is no flaking or peeling on the sample ×: There is flaking or peeling on the sample

Production of Copolymer Polyester (A1) Raw materials were charged into an esterification reaction vessel so that the acid components were 50.0 mol % of terephthalic acid and 49.2 mol % of isophthalic acid, the glycol components were 44.0 mol % of ethylene glycol, 49.0 mol % of neopentyl glycol, 6.0 mol % of polytetramethylene glycol having a number average molecular weight of 1000, and 1.0 mol % of diethylene glycol, and the hindered phenol-based antioxidant was 0.25 mass % based on the obtained copolymer polyester, and esterification was carried out at 250° C. for 5 hours under a pressure of 0.25 MPa with stirring to produce an esterified product.
Thereafter, the mixture was transferred to a polycondensation vessel, a polymerization catalyst was added, the pressure was gradually reduced to 1.3 hPa over 60 minutes, and a polycondensation reaction was carried out at 250° C. until a predetermined molecular weight was reached.
Next, the polycondensation tank was filled with nitrogen to a pressure of 0.1 MPa, trimellitic anhydride was added so that the acid component was 0.8 mol %, and a depolymerization reaction was carried out at 250° C. for 2 hours with stirring to obtain a copolymerized polyester.
The resulting copolymer polyester had a number average molecular weight of 18,000, an acid value of 4 mgKOH/g and a glass transition temperature of 5°C.

Preparation of Copolymer Polyesters (A2) to (A6), (A8) to (A9), and (A12) to (A15) Copolymer polyesters were obtained in the same manner as in Example 1, except that the compositions of the copolymer polyesters were changed as shown in Table 1.

Production of copolymerized polyesters (A7), (A10) to (A11) Copolymerized polyesters were produced in the same manner as in Example 1, except that the composition of the copolymerized polyester was changed as shown in Table 1, and the depolymerization reaction was not performed. A polymerized polyester was obtained.

Production of copolymerized polyester (A16) Using 80 parts by mass of copolymerized polyester (A9) and 20 parts by mass of copolymerized polyester (A10), the solid content was added to a mixed solvent of toluene/methyl ethyl ketone (8/2 (mass ratio)). The solution was dissolved to a concentration of 25% by mass, air-dried at room temperature for 24 hours, and heat-treated at 100° C. for 6 hours to obtain a copolyester blend (A16). The obtained copolyester blend (A16) had an acid value of 4 mgKOH/g and a glass transition temperature of 6°C.

Production of copolyester (A17) Using 20 parts by mass of copolyester (A10) and 80 parts by mass of copolyester (A11), the solid content was added to a mixed solvent of toluene/methyl ethyl ketone (8/2 (mass ratio)). The solution was dissolved to a concentration of 25% by mass, air-dried at room temperature for 24 hours, and heat-treated at 100° C. for 6 hours to obtain a copolyester blend (A17). The obtained copolymerized polyester blend (A17) had an acid value of 1 mgKOH/g and a glass transition temperature of 7°C.

Example 1
100 parts by mass of copolymerized polyester (A1) was dissolved in a mixed solvent of toluene/methyl ethyl ketone (8/2 (mass ratio)) so that the solid content concentration was 25 mass%, and 5 parts by mass of an epoxy compound and 0.35 parts by mass of an imidazole compound were added to obtain a solution of an adhesive composition.
The solution was applied to a polyimide film (Kapton 200H, 50 μm thick, manufactured by DuPont-Toray Co., Ltd.) using a bar coater and heat-treated at 180° C. for 30 seconds to obtain a laminate in which an adhesive composition layer having a dry thickness of 15 μm was laminated on the polyimide film.

Examples 2 to 9, Comparative Examples 1 to 14
A laminate in which the adhesive composition solution and the adhesive composition layer were laminated was obtained in the same manner as in Example 1, except that the type of copolymerized polyester and the added amounts of the epoxy compound and the imidazole compound were changed as shown in Table 1.

Comparative example 15
A laminate in which the solution of the adhesive composition and the adhesive composition were laminated was obtained in the same manner as in Example 1 except that the epoxy compound was changed to an isocyanate compound (isophorone diisocyanate, containing 38% isocyanate).

The composition and properties of the adhesive compositions obtained in the examples and comparative examples are shown in Table 1.

The adhesive compositions obtained in Examples 1 to 9 satisfied the configurations specified in the present invention, and therefore had excellent adhesive properties as well as moist heat resistance and soldering heat resistance.

The adhesive compositions of Comparative Examples 1 and 2 had epoxy compound contents outside the range specified by the present invention, and therefore were inferior in adhesion or solder heat resistance.
The adhesive compositions of Comparative Examples 3 and 4 had inferior adhesion or solder heat resistance because the content of the imidazole compound was outside the range specified in the present invention.
The adhesive compositions of Comparative Examples 5 and 14 had poor solder heat resistance because the acid value of the copolymer polyester was less than 2 mgKOH/g.
The adhesive compositions of Comparative Examples 6 to 9 had poor adhesive properties because the acid value and/or glass transition temperature of the copolymerized polyester was outside the range specified by the present invention.
The adhesive compositions of Comparative Examples 10 and 11 had poor adhesion because the content of isophthalic acid or glycol having a side chain in the copolymer polyester was outside the range specified in the present invention.
The adhesive composition of Comparative Example 12 had a polyalkylene glycol content of 2 to 4 carbon atoms in the repeating unit and a number average molecular weight of 200 or more that exceeded the range specified in the present invention, and therefore had poor solder heat resistance.
The adhesive composition of Comparative Example 13 had a low content of polyalkylene glycol having a repeating unit with 2 to 4 carbon atoms and a number average molecular weight of 200 or more, outside the range specified in the present invention, and therefore had poor moist heat resistance.
The adhesive composition of Comparative Example 15 was inferior in solder heat resistance because an isocyanate compound was used instead of an epoxy compound.

Claims (2)

Containing 100 parts by mass of copolymerized polyester, 3 to 13 parts by mass of epoxy compound, and 0.3 to 0.9 parts by mass of imidazole compound,
The copolymerized polyester contains 30 mol% or more of isophthalic acid in the acid component, 30 mol% or more of glycol having a side chain in the glycol component, the number of carbon atoms in the repeating unit is 2 to 4, and a number average molecular weight. contains 1 to 20 mol% of polyalkylene glycol having 200 or more,
An adhesive composition characterized in that the copolymerized polyester has an acid value of 2 to 8 mgKOH/g and a glass transition temperature of -10 to 10°C. A laminate comprising a layer made of the adhesive composition according to claim 1.