JP6650123B2 - Polyester modified epoxy resin and adhesive - Google Patents

Description

  The present invention relates to a polyester-modified epoxy resin having excellent flexibility and toughness in a cured product, a curable composition containing the same, a cured product thereof, and an adhesive.

  In recent years, lightweight materials such as aluminum, magnesium, and plastic have been adopted as automobile body materials from the viewpoint of energy saving, and adhesives have been increasingly used in assembling instead of welding. The characteristics of automotive adhesives are that they are used for bonding between different materials and that the temperature of the operating environment changes very sharply.Currently, epoxy resin adhesives with excellent heat resistance and mechanical properties are mainly used. ing. However, conventional epoxy resin-based adhesives have insufficient flexibility and toughness in cured products and cannot follow thermal deformation of members, and thus have a problem that distortion and peeling easily occur in high-temperature and low-temperature environments. In particular, when different materials such as a metal material and a non-metal material are bonded, the difference in thermal expansion coefficient between the two materials is large, and the problems of distortion and peeling have been remarkable.

  A lactone-modified epoxy resin obtained by reacting a bisphenol A type epoxy resin with ε-caprolactone at a mass ratio of 90/10 to 80/20 is known as an epoxy resin having excellent flexibility in a cured product ( However, the flexibility and toughness of the cured product were not such that they could be used for automotive adhesives.

JP-A-58-32628

  Accordingly, an object of the present invention is to provide a polyester-modified epoxy resin having excellent flexibility and toughness in a cured product, a curable composition containing the same, a cured product thereof, and an adhesive.

  The present inventors have conducted intensive studies in order to solve the above problems, and as a result, reacted the epoxy resin having a hydroxyl group and the lactone compound at a ratio by which the mass ratio of both becomes 55/45 to 65/35. The resulting polyester-modified epoxy resin was found to have excellent flexibility and toughness in the cured product, and was suitable for use in adhesives, and completed the present invention.

  That is, the present invention provides the following general formula (1)

［式中Ｒ^１は水素原子又はポリエステル構造部位であり、Ｘはそれぞれ独立に下記一般式（２−１）〜（２−８）

[Wherein R ¹ is a hydrogen atom or a polyester structure site, and Xs are each independently the following general formulas (2-1) to (2-8)

（式中、Ｒ^２はそれぞれ独立に水素原子、炭素原子数１〜４のアルキル基、炭素原子数１〜４のアルコキシ基の何れかであり、Ｒ^３はそれぞれ独立に炭素原子数１〜４のアルキル基、炭素原子数１〜４のアルコキシ基の何れかであり、ｎは１以上の整数である。）
の何れかで表される構造部位である。］
で表される分子構造を有する化合物（Ｚ）を含有し、樹脂中に存在する前記Ｒ^１の少なくとも一つはポリエステル構造部位であり、ポリエステル構造部位の含有量が３５〜４５質量％の範囲であることを特徴とするポリエステル変性エポキシ樹脂に関する。

(Wherein, R ² is independently any one of a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, and an alkoxy group having 1 to 4 carbon atoms, and R ³ is each independently a group having 1 to 4 carbon atoms. Is an alkyl group or an alkoxy group having 1 to 4 carbon atoms, and n is an integer of 1 or more.)
Is a structural site represented by any of the above. ]
Wherein at least one of the R ¹ present in the resin is a polyester structural site, and the content of the polyester structural site is in the range of 35 to 45% by mass. The present invention relates to a polyester-modified epoxy resin characterized by the following.

  The present invention further comprises reacting the epoxy resin (A) having a hydroxyl group with the lactone compound (B) in such a ratio that the mass ratio [(A) / (B)] of both becomes 55/45 to 65/35. The present invention relates to a polyester-modified epoxy resin having a molecular structure obtained by the above.

  The present invention further relates to a curable composition containing the polyester-modified epoxy resin and a curing agent or a curing accelerator.

  The present invention further relates to a cured product obtained by curing the curable composition.

  The present invention further relates to an adhesive containing the polyester-modified epoxy resin and a curing agent.

  According to the present invention, it is possible to provide a polyester-modified epoxy resin having excellent flexibility and toughness in a cured product, a curable composition containing the same, a cured product thereof, and an adhesive.

FIG. 1 is a GPC chart of the polyester-modified epoxy resin (1) obtained in Example 1. FIG. 2 is a GPC chart of the polyester-modified epoxy resin (2) obtained in Example 2.

Hereinafter, the present invention will be described in detail.
The polyester-modified epoxy resin of the present invention has the following general formula (1)

［式中Ｒ^１は水素原子又はポリエステル構造部位であり、Ｘはそれぞれ独立に下記一般式（２−１）〜（２−８）

[Wherein R ¹ is a hydrogen atom or a polyester structure site, and Xs are each independently the following general formulas (2-1) to (2-8)

（式中、Ｒ^２はそれぞれ独立に水素原子、炭素原子数１〜４のアルキル基、炭素原子数１〜４のアルコキシ基の何れかであり、Ｒ^３はそれぞれ独立に炭素原子数１〜４のアルキル基、炭素原子数１〜４のアルコキシ基の何れかであり、ｎは１以上の整数である。）
の何れかで表される構造部位である。］
で表される分子構造を有する化合物（Ｚ）を含有し、樹脂中に存在する前記Ｒ^１の少なくとも一つはポリエステル構造部位であり、ポリエステル構造部位の含有量が３５〜４５質量％の範囲であることを特徴とする。

(Wherein, R ² is independently any one of a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, and an alkoxy group having 1 to 4 carbon atoms, and R ³ is each independently 1 to 4 carbon atoms. Is an alkyl group or an alkoxy group having 1 to 4 carbon atoms, and n is an integer of 1 or more.)
Is a structural site represented by any of the above. ]
Wherein at least one of the R ¹ present in the resin is a polyester structural site, and the content of the polyester structural site is in the range of 35 to 45% by mass. There is a feature.

  X in the general formula (1) is a structural site represented by any of the general formulas (2-1) to (2-8), and a plurality of Xs in the molecule are the same structural site. Or different structural parts. Among them, a structural part represented by the general formula (2-1) or (2-2) is preferable because the cured product has excellent flexibility and toughness.

  The polyester-modified epoxy resin of the present invention is obtained, for example, by mixing a hydroxyl group-containing epoxy resin (A) and a lactone compound (B) in a mass ratio [(A) / (B)] of 55/45 to 65/35. It is obtained by reacting at a ratio within the range.

  The epoxy resin (A) having a hydroxyl group is, for example, represented by the following general formula (3)

［式中Ｘはそれぞれ独立に下記一般式（２−１）〜（２−８）

[Wherein X is independently the following general formulas (2-1) to (2-8)

（式中、Ｒ^２はそれぞれ独立に水素原子、炭素原子数１〜４のアルキル基、炭素原子数１〜４のアルコキシ基の何れかであり、Ｒ^３はそれぞれ独立に炭素原子数１〜４のアルキル基、炭素原子数１〜４のアルコキシ基の何れかであり、ｎは１以上の整数である。）
の何れかで表される構造部位である。］
で表される分子構造を有するものが挙げられる。

(Wherein, R ² is independently any one of a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, and an alkoxy group having 1 to 4 carbon atoms, and R ³ is each independently 1 to 4 carbon atoms. Is an alkyl group or an alkoxy group having 1 to 4 carbon atoms, and n is an integer of 1 or more.)
Is a structural site represented by any of the above. ]
And those having a molecular structure represented by

  The epoxy equivalent of the epoxy resin (A) having a hydroxyl group is such that the cured product thereof is excellent in flexibility and toughness, and the fluidity is a value suitable for use in an adhesive, in the finally obtained polyester-modified epoxy resin. For this reason, the range is preferably 370 to 600 g / equivalent.

  Examples of the method for producing the epoxy resin (A) having a hydroxyl group include, for example, a method of reacting a bisphenol or biphenol type compound (a1) with these diglycidyl ether compounds (a2) (method 1), or a method of reacting bisphenol or bisphenol. A method (method 2) of reacting the type compound (a1) with epihalohydrin is exemplified. Among them, method 1 is preferable because the reaction is easily controlled and the epoxy equivalent of the obtained epoxy resin (A) is easily controlled to the preferable value.

  Regarding the method 1, the reaction ratio between the bisphenol or biphenol type compound (a1) and the diglycidyl ether compound (a2) is such that the mass ratio [(a1) / (a2)] of the two is 10/90 to 30 /. It is preferably in the range of 70. The reaction temperature is preferably about 120 to 160 ° C., and a reaction catalyst such as tetramethylammonium chloride may be used.

  Next, the lactone compound (B) is not particularly limited as long as it has a cyclic ester structure. For example, β-propiolactone, γ-butyrolactone, δ-valerolactone, ε-caprolactone, 7-hydroxyheptane Lactones having a 4- to 10-membered ring such as acid lactone, 8-hydroxyoctanoic acid lactone, and 9-hydroxynonanoic acid lactone are exemplified. Among them, ε-caprolactone is preferable because it becomes a polyester-modified epoxy resin having excellent flexibility and toughness in a cured product.

  The reaction between the epoxy resin (A) having a hydroxyl group and the lactone compound (B) may be carried out, for example, in the presence of a suitable reaction catalyst at a temperature of about 100 to 130 ° C.

  The epoxy equivalent of the thus obtained polyester-modified epoxy resin of the present invention is preferably in the range of 500 to 1000 g / equivalent because the cured product has excellent flexibility and toughness.

  The curable composition of the present invention contains the polyester-modified epoxy resin and a curing agent or a curing accelerator.

  As the curing agent or curing accelerator, those generally used for curing epoxy resins can be widely used, for example, polyamine compounds, amide compounds, acid anhydrides, phenolic hydroxyl group-containing resins, phosphorus compounds , Imidazole compounds, imidazoline compounds, urea compounds, organic acid metal salts, Lewis acids, amine complex salts and the like.

  Examples of the polyamine compound include trimethylenediamine, ethylenediamine, N, N, N ′, N′-tetramethylethylenediamine, pentamethyldiethylenetriamine, triethylenediamine, dipropylenediamine, N, N, N ′, N′-tetramethyl. Propylene diamine, tetramethylene diamine, pentane diamine, hexamethylene diamine, trimethyl hexamethylene diamine, N, N, N ', N'-tetramethyl hexamethylene diamine, N, N-dimethylcyclohexylamine, diethylene triamine, triethylene tetramine, tetraethylene Ethylenepentamine, dimethylaminopropylamine, diethylaminopropylamine, dibutylaminopropylamine, 1,4-diazabicyclo (2,2,2) octane (triethylene Amine), polyoxyethylene diamine, polyoxypropylene diamine, bis (2-dimethylaminoethyl) ether, dimethylaminoethoxy ethoxyethanol, triethanolamine, aliphatic amine compounds such as dimethylamino hexanol;

  Piperidine, piperazine, menthanediamine, isophoronediamine, methylmorpholine, ethylmorpholine, N, N ′, N ″ -tris (dimethylaminopropyl) hexahydro-s-triazine, 3,9-bis (3-aminopropyl) -2, 4,8,10-tetraoxyspiro (5,5) undecane adduct, N-aminoethylpiperazine, trimethylaminoethylpiperazine, bis (4-aminocyclohexyl) methane, N, N'-dimethylpiperazine, 1,8-diazabicyclo Alicyclic and heterocyclic amine compounds such as-[5.4.0] -undecene (DBU);

  aromatic amines such as o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, benzylmethylamine, dimethylbenzylamine, m-xylenediamine, pyridine, picoline, α-methylbenzylmethylamine Compound;

  Epoxy compound added polyamine, Michael added polyamine, Mannich added polyamine, thiourea added polyamine, ketone-blocked polyamine, dicyandiamide, guanidine, organic acid hydrazide, diaminomaleonitrile, amine imide, boron trifluoride-piperidine complex, boron trifluoride-mono Modified amine compounds such as an ethylamine complex are exemplified.

  Examples of the amide compound include dicyandiamide and polyamidoamine. The polyamidoamines include, for example, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, aliphatic dicarboxylic acids such as azelaic acid, fatty acids, carboxylic acid compounds such as dimer acid, and aliphatic polyamines and polyoxyalkylenes. Those obtained by reacting a polyamine having a chain and the like can be mentioned.

  Examples of the acid anhydride include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride, and methylhexahydro. And phthalic anhydride.

  Examples of the phenolic hydroxyl group-containing resin include phenol novolak resin, cresol novolak resin, aromatic hydrocarbon formaldehyde resin-modified phenol resin, dicyclopentadiene phenol addition type resin, phenol aralkyl resin (Xyloc resin), naphthol aralkyl resin, Trimethylolmethane resin, tetraphenylolethane resin, naphthol novolak resin, naphthol-phenol co-condensed novolak resin, naphthol-cresol co-condensed novolak resin, biphenyl-modified phenol resin (polyphenol compound with phenol nucleus linked by bismethylene group) , Biphenyl-modified naphthol resin (a polyvalent naphthol compound having a phenol nucleus linked by a bismethylene group), aminotriazine-modified phenol resin (melamine, benzo Polyhydric phenol compounds such as a polyhydric phenol compound having a phenol nucleus linked with an anamine or the like and an alkoxy group-containing aromatic ring-modified novolak resin (a polyphenol compound having a phenol nucleus and an alkoxy group-containing aromatic ring linked with formaldehyde) are used. No.

  Examples of the phosphorus compound include: alkyl phosphines such as ethyl phosphine and butyl phosphine; first phosphines such as phenyl phosphine; dialkyl phosphines such as dimethyl phosphine and dipropyl phosphine; second phosphines such as diphenyl phosphine and methyl ethyl phosphine; trimethyl phosphine And tertiary phosphines such as triethylphosphine and triphenylphosphine.

  Examples of the imidazole compound include, for example, imidazole, 1-methylimidazole, 2-methylimidazole, 3-methylimidazole, 4-methylimidazole, 5-methylimidazole, 1-ethylimidazole, 2-ethylimidazole, 3-ethylimidazole, -Ethylimidazole, 5-ethylimidazole, 1-n-propylimidazole, 2-n-propylimidazole, 1-isopropylimidazole, 2-isopropylimidazole, 1-n-butylimidazole, 2-n-butylimidazole, 1-isobutyl Imidazole, 2-isobutylimidazole, 2-undecyl-1H-imidazole, 2-heptadecyl-1H-imidazole, 1,2-dimethylimidazole, 1,3-dimethylimidazole, 2,4-dimethyl Louisimidazole, 2-ethyl-4-methylimidazole, 1-phenylimidazole, 2-phenyl-1H-imidazole, 4-methyl-2-phenyl-1H-imidazole, 2-phenyl-4-methylimidazole, 1-benzyl- 2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl- 2-phenylimidazole, 2-phenylimidazole isocyanuric acid adduct, 2-methylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, - include cyanoethyl-2-phenyl-4,5-di (2-cyanoethoxy) methylimidazole, 1-dodecyl-2-methyl-3-benzyl-imidazolium chloride, 1-benzyl-2-phenylimidazole hydrochloride etc.

  Examples of the imidazoline compound include 2-methylimidazoline and 2-phenylimidazoline.

  Examples of the urea compound include p-chlorophenyl-N, N-dimethylurea, 3-phenyl-1,1-dimethylurea, 3- (3,4-dichlorophenyl) -N, N-dimethylurea, and N- (3 -Chloro-4-methylphenyl) -N ', N'-dimethylurea and the like.

  Among these curing agents or curing accelerators, any of an imidazole compound, an amine compound, and an amide compound are preferable because of high adhesive strength when used for an adhesive. Further, among the amine compounds, a polyetheramine having a polyoxyalkylene structure site in the molecular structure is more preferable.

  The curable composition of the present invention may be used in combination with another epoxy resin other than the polyester-modified epoxy resin of the present invention. Other epoxy resins include, for example, bisphenol type epoxy resins such as bisphenol A type, F type and S type, alkoxy-modified bisphenol type epoxy resin, phenol novolak type, naphthol novolak type, cresol novolak type, phenol-cresol co-condensed novolak type And the like, a novolak-type epoxy resin, a urethane-modified epoxy resin, a triphenylmethane-type epoxy resin, and the like.

  In the present invention, the blending amount of the epoxy resin component and the curing agent or the curing accelerator is such that when a curing agent having a functional group capable of reacting with an epoxy group is used, the curing is performed with respect to 1 mol of the epoxy group in the epoxy resin component. It is preferable to mix the functional groups in the composition at a ratio of 0.9 to 1.1 mol. When a curing accelerator is used, it is preferable to mix the curing accelerator in an amount of 0.5 to 10 parts by mass with respect to 100 parts by mass of the epoxy resin component.

  The curable composition of the present invention may further include an organic solvent, an ultraviolet absorber, an antioxidant, a silicon-based additive, a fluorine-based additive, a flame retardant, a plasticizer, a silane coupling agent, an organic bead, inorganic fine particles, It may contain an inorganic filler, a rheology control agent, a defoaming agent, an antifogging agent, a colorant, and the like. These various components may be added in optional amounts depending on the desired performance.

  The curable composition of the present invention comprises the above-mentioned polyester-modified epoxy resin, a curing agent or a curing accelerator, and the above-mentioned various optional components in a pot mill, a ball mill, a bead mill, a roll mill, a homogenizer, a super mill, a homodisper, a universal mixer, and a Banbury. It can be prepared by mixing uniformly using a mixer, kneader or the like.

  The use of the curable composition of the present invention is not particularly limited, and the curable composition can be used for various uses such as a paint, a coating agent, a molding material, an insulating material, a sealant, a sealant, and a fiber binding agent. Above all, the cured product can be suitably used as an adhesive for structural members in the fields of automobiles, trains, civil engineering, electronics, aircraft, and the space industry, taking advantage of its excellent flexibility and toughness. The adhesive of the present invention can maintain high adhesiveness without being affected by changes in the temperature environment, for example, even when used for bonding different materials such as a metal and a non-metal. hard. In addition, the adhesive of the present invention can be used as an adhesive for general office work, medical use, carbon fiber, electronic materials, and the like, in addition to structural members, and as an adhesive for electronic materials, for example, build-up Adhesives for interlayer of multi-layer substrates such as substrates, adhesives for bonding optical components, adhesives for bonding optical disks, adhesives for mounting printed wiring boards, die bonding adhesives, adhesives for semiconductors such as underfill, BGA reinforcement under An adhesive for mounting such as a fill, an anisotropic conductive film, and an anisotropic conductive paste may be used.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.

Example 1 Production of Polyester-Modified Epoxy Resin (1) In a flask equipped with a thermometer, a stirrer, and a reflux condenser, 48 mass of bisphenol A type epoxy resin ("EPICLON 850" epoxy equivalent, 188 g / equivalent, manufactured by DIC Corporation) was added. Parts, 12 parts by mass of bisphenol A, and 0.002 parts by mass of tetramethylammonium chloride as a catalyst, and the mixture was heated to 140 ° C., stirred and reacted until the epoxy equivalent reached 400 g / equivalent. A-1) was obtained. Then, the temperature inside the reaction system was lowered to 110 ° C., and 40 parts by mass of ε-caprolactone and 0.05 parts by mass of dioctyltin catalyst (“Neostan U-820” manufactured by Nitto Kasei Co., Ltd.) were added. The reaction was performed until the nonvolatile content became 99% by mass or more to obtain a polyester-modified epoxy resin (1), and the obtained polyester-modified epoxy resin (1) had an epoxy equivalent of 670 g / equivalent.

Example 2 Production of Polyester-Modified Epoxy Resin (2) In a flask equipped with a thermometer, a stirrer, and a reflux condenser, 49 mass of bisphenol F type epoxy resin ("EPICLON 830" epoxy equivalent 170 g / equivalent, manufactured by DIC Corporation) was added. Parts, 11 parts by mass of bisphenol F, and 0.002 parts by mass of tetramethylammonium chloride as a catalyst. The mixture was heated to 140 ° C., stirred and reacted until the epoxy equivalent reached 400 g / equivalent. A-2) was obtained. Then, the temperature inside the reaction system was lowered to 110 ° C., and 40 parts by mass of ε-caprolactone and 0.05 parts by mass of dioctyltin catalyst (“Neostan U-820” manufactured by Nitto Kasei Co., Ltd.) were added. The reaction was performed until the nonvolatile content became 99% by mass or more to obtain a polyester-modified epoxy resin (2), and the obtained polyester-modified epoxy resin (2) had an epoxy equivalent of 590 g / equivalent.

Example 3 Production of Polyester-Modified Epoxy Resin (3) Bisphenol A type epoxy resin ("EPICLON 850" epoxy equivalent: 188 g / equivalent, manufactured by DIC Corporation) was placed in a flask equipped with a thermometer, a stirrer, and a reflux condenser. 5 parts by mass, 13.5 parts by mass of bisphenol A, and 0.002 parts by mass of tetramethylammonium chloride as a catalyst were charged, and the mixture was heated to 140 ° C. and stirred until the epoxy equivalent reached 470 g / equivalent. The resulting epoxy resin (A-3) was obtained. Then, the temperature inside the reaction system was lowered to 110 ° C., and 40 parts by mass of ε-caprolactone and 0.05 parts by mass of dioctyltin catalyst (“Neostan U-820” manufactured by Nitto Kasei Co., Ltd.) were added. The reaction was performed until the nonvolatile content became 99% by mass or more to obtain a polyester-modified epoxy resin (3), which had an epoxy equivalent of 800 g / equivalent.

Comparative Production Example 1 Production of Polyester-Modified Epoxy Resin (1 ') Bisphenol A type epoxy resin ("EPICLON 850" epoxy equivalent: 188 g / equivalent, manufactured by DIC Corporation) was placed in a flask equipped with a thermometer, a stirrer, and a reflux condenser. 75 parts by mass, 25 parts by mass of ε-caprolactone, and 0.05 parts by mass of dioctyltin catalyst (“Neostan U-820” manufactured by Nitto Kasei Co., Ltd.) were heated. The reaction was continued until a polyester-modified epoxy resin (1 ′) was obtained, which had an epoxy equivalent of 250 g / equivalent.

Comparative Production Example 2 Production of Polyester-Modified Epoxy Resin (2 ′) Bisphenol A type epoxy resin (“EPICLON 850” epoxy equivalent: 188 g / equivalent, manufactured by DIC Corporation) was placed in a flask equipped with a thermometer, a stirrer, and a reflux condenser. 45 parts by mass, 55 parts by mass of ε-caprolactone, and 0.05 parts by mass of dioctyltin catalyst (“Neostan U-820” manufactured by Nitto Kasei Co., Ltd.). The mixture was heated to 120 ° C. to increase the non-volatile content to 99% by mass or more. The reaction was continued until the polyester-modified epoxy resin (2 ′) was obtained, which had an epoxy equivalent of 420 g / equivalent.

Examples 4 to 6, Comparative Examples 1 and 2
Preparation and evaluation of curable composition (I) Curable composition (I) was prepared using the polyester-modified epoxy resin obtained in Examples 1 to 3 and Comparative Production Examples 1 and 2 in the following manner, and the cured product was obtained. Various evaluation tests were carried out on. Table 1 shows the results.

Preparation of Curable Composition (I) A polyester-modified epoxy resin, 2-ethyl-4-methylimidazole, and 3- (3,4-dichlorophenyl) -N, N-dimethylurea were blended in the proportions shown in Table 1, A curable composition (I) was obtained.

Tensile test The curable composition (I) obtained above was poured into a mold having a thickness of 2 mm, and cured at 150 ° C for 1 hour. A No. 1 dumbbell-shaped sample was cut out from the cured product, and a tensile test was performed using “AUTOGRAPH AG-IS 1 kN” manufactured by Shimadzu Corporation to evaluate the elongation (%).

Adhesion test Two sheets of steel sheet were bonded by thermosetting using the curable composition (I) obtained above. The thickness of the adhesive layer was set to 0.2 mm, and it was cured by heating at 150 ° C. for 1 hour. The obtained adhesive test steel sheet was subjected to a tensile shear test using “AUTOGRAPH AG-IS 10 kN” manufactured by Shimadzu Corporation based on JIS K6859 (creep fracture test of adhesive), and evaluated by breaking strength (MPa). .

Examples 7 to 15
Preparation and evaluation of curable compositions (II) to (IV) Curable compositions (II) to (IV) were prepared using the polyester-modified epoxy resin obtained in Examples 1 to 3 in the following manner, and cured. Various evaluation tests were performed on the product. The results are shown in Tables 2 to 4.

Preparation of Curable Composition (II) Polyester-modified epoxy resin and polyetheramine ("JEFFAMINE D-230" manufactured by Huntsman Co., active hydrogen equivalent: 57 g / equivalent) were blended in the ratio shown in Table 2 to obtain curable composition (II). ) Got.

Tensile test The curable composition (II) obtained above was poured into a mold so as to have a film thickness of 2 mm, and was heated and cured at 80 ° C, 100 ° C, and 120 ° C for 3 hours each. A No. 1 dumbbell-shaped sample was cut out from the cured product, and a tensile test was performed using “AUTOGRAPH AG-IS 1 kN” manufactured by Shimadzu Corporation to evaluate the elongation (%).

Adhesion test Two sheets of steel sheet were bonded by thermosetting using the curable composition (II) obtained above. The thickness of the adhesive layer was 0.2 mm, and the coating was heated and cured at 80 ° C., 100 ° C., and 120 ° C. in this order for 3 hours. The obtained test steel sheet was subjected to a tensile shear test using “AUTOGRAPH AG-IS 10 kN” manufactured by Shimadzu Corporation based on JIS K6859 (creep fracture test of adhesive), and evaluated by breaking strength (MPa).

Preparation of Curable Composition (III) A polyester-modified epoxy resin, dicyandiamide, and 3,4-dichlorophenyl-N, N-dimethylurea were blended at a ratio shown in Table 3 to obtain a curable composition (III).

Tensile test The curable composition (III) obtained above was poured into a mold so as to have a thickness of 2 mm, and was cured by heating at 180 ° C for 1 hour. A No. 1 dumbbell-shaped sample was cut out from the cured product, and a tensile test was performed using “AUTOGRAPH AG-IS 1 kN” manufactured by Shimadzu Corporation to evaluate the elongation (%).

Adhesion test Two sheets of steel sheet were bonded by thermosetting using the curable composition (III) obtained above. The thickness of the adhesive layer was set to 0.2 mm, and it was cured by heating at 180 ° C. for 1 hour. The obtained adhesive test steel sheet was subjected to a tensile shear test using “AUTOGRAPH AG-IS 10 kN” manufactured by Shimadzu Corporation based on JIS K6859 (creep fracture test of adhesive), and evaluated by breaking strength (MPa). .

Preparation of Curable Composition (IV) A polyester-modified epoxy resin and an amide resin ("Lacamide TD-960" manufactured by DIC Corporation, active hydrogen equivalent: 78 g / equivalent) were blended in the ratio shown in Table 4 to obtain a curable composition (IV). ) Got.

Tensile test The curable composition (IV) obtained above was poured into a mold so as to have a film thickness of 2 mm, and heated and cured at 80 ° C, 100 ° C, and 120 ° C for 3 hours each. A No. 1 dumbbell-shaped sample was cut out from the cured product, and a tensile test was performed using “AUTOGRAPH AG-IS 1 kN” manufactured by Shimadzu Corporation to evaluate the elongation (%).

Adhesion test Two sheets of steel sheet were bonded by thermosetting using the curable composition (IV) obtained above. The thickness of the adhesive layer was 0.2 mm, and the coating was heated and cured at 80 ° C., 100 ° C., and 120 ° C. in this order for 3 hours. The obtained adhesive test steel sheet was subjected to a tensile shear test using “AUTOGRAPH AG-IS 10 kN” manufactured by Shimadzu Corporation based on JIS K6859 (creep fracture test of adhesive), and evaluated by breaking strength (MPa). .

Claims (9)

The following general formula (1)

[Wherein R 1 is a hydrogen atom or a polyester structure site, and Xs are each independently the following general formulas (2-1) to (2-8)

(Wherein, R ² is independently any one of a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, and an alkoxy group having 1 to 4 carbon atoms, and R 3 is each independently a group having 1 to 4 carbon atoms. Any of an alkyl group and an alkoxy group having 1 to 4 carbon atoms, and n is an integer of 1 or more.)
Is a structural site represented by any of the above. ]
Wherein at least one of the R ¹ present in the resin is a polyester structural site, and the content of the polyester structural site is in the range of 35 to 45% by mass. there is a polyester-modified epoxy resin, and an epoxy equivalent weight of the polyester-modified epoxy resin is Ri range der of 500 to 1000 g / eq,
The polyester-modified epoxy resin, polyester-modified Epoxy resin, characterized in that is obtained by an epoxy resin (A) and lactonized compound having a hydroxyl group and (B) are reacted. The polyester modified according to claim 1, wherein the lactone compound (B) is ε-caprolactone. Epoxy resin. The epoxy resin (A) having a hydroxyl group and the lactone compound (B) are mass ratio of both. [(A) / (B)] was reacted at a ratio in the range of 55/45 to 65/35. 3. The polyester-modified epoxy resin according to claim 1 or 2. The epoxy equivalent of the epoxy resin (A) having a hydroxyl group is in the range of 370 to 600 g / equivalent. The polyester-modified epoxy resin according to any one of claims 1 to 3, wherein A curable composition comprising the polyester-modified epoxy resin according to any one of claims 1 to 4, and a curing agent or a curing accelerator. The curable composition according to claim 5, wherein the curing agent or the curing accelerator is any of an imidazole compound, a polyetheramine compound, and an amide compound. A cured product obtained by curing the curable composition according to claim 5 . Adhesives containing a polyester-modified epoxy resin; and a curing agent to one of claims 1 to 4. The adhesive according to claim 8 , wherein the curing agent is a polyetheramine having a polyoxyalkylene structure site in a molecular structure.

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