JPH055860B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention provides a block copolymer consisting of an epoxy resin, a vinyl aromatic polymer block and a conjugated diene polymer block, and/or a hydrogenated product thereof, an α,β-unsaturated glycidyl compound. The present invention relates to an epoxy resin composition comprising a modified product, and provides an epoxy resin composition having improved adhesion and excellent impact resistance, heat resistance, water resistance, solvent resistance, etc. [Prior art and its problems] General epoxy resins that have benzene rings in their molecular skeletons, such as epoxy resins derived from bisphenol A and epichlorohydrin, have excellent mechanical and chemical properties and adhesive properties. It is widely used in industrial applications such as electrical insulation materials, paints, adhesives, and fiber-reinforced composite materials. However, cured products of these general epoxy resins are rigid and have the disadvantage of being inferior in impact resistance and adhesive peel strength due to large internal stress and shrinkage that occur during curing. One way to overcome these drawbacks is to use epoxy resins and curing agents that have flexible chemical bonds in their molecular skeletons to soften the cured product and reduce internal stress. Another problem is a decrease in heat resistance and water resistance. Therefore, as a method to improve the impact resistance and adhesive peel strength while maintaining the heat resistance and water resistance of the cured product, a method has been proposed in which an elastomer component is mixed with the epoxy resin and the elastomer component is dispersed in the epoxy resin matrix. has been done. Elastomer components that can serve this purpose include natural rubber, synthetic rubber, polyamide resin, vinyl chloride-vinyl acetate copolymer, acrylic resin, silicone resin, polyester elastomer, and polyurethane elastomer, among which synthetic rubber has been widely used. This synthetic rubber is generally a liquid acrylonitrile-butadiene copolymer (functional group-containing NBR) having a functional group at the end of the molecule. However, although this functional group-containing NBR can improve impact resistance and adhesive peel strength to some extent, the level is not sufficient, and
There is a problem in that it tends to cause thermal deterioration.
For this improvement, JP-A-57-149369 and JP-A-57-149370 disclose that an epoxy resin has (1) a block made of a monovinyl aromatic compound polymer and (2)
A composition having excellent adhesive properties has been proposed by adding a modified block copolymer obtained by grafting an unsaturated carboxylic acid to a hydrogenated product of a block copolymer consisting of a block made of a conjugated diolefin polymer. However, even when these modified block copolymers are modified with maleic anhydride, which is said to be the most preferable among them, when the starting polymer is reacted with maleic anhydride under heating, the modified block copolymer is may become discolored, or due to the presence of small amounts of unreacted maleic anhydride or low polymers of maleic anhydride, compositions containing these may decompose and foam during the heat curing process or subsequent heating conditions. However, the adhesive hardness is lowered and the appearance deteriorates, so that the results are not always satisfactory. Moreover, these tendencies become more pronounced as the graft modification rate is increased, and there has been no effective preventive measure. [Means for Solving the Problems] The present invention aims to solve these problems, and in a composition of an epoxy resin and a modified block copolymer, the initial objective of improving adhesion and The present invention provides an epoxy resin composition that provides excellent impact resistance, heat resistance, water resistance, solvent resistance, etc., and at the same time does not deteriorate performance or appearance due to coloring or foaming. That is, the present invention comprises (a) 100 parts by weight of an epoxy resin having two or more epoxy groups in one molecule; (b) a polymer block A mainly composed of at least one vinyl aromatic compound; Glycidyl-modified block copolymers 2 to 100 obtained by modifying a block copolymer consisting of a polymer block B mainly composed of a conjugated diene compound and/or a hydrogenated product thereof with an α,β-unsaturated glycidyl compound
Parts by weight of an epoxy resin composition are provided. The epoxy resin used in the present invention may have any structure as long as it has two or more epoxy groups in one molecule. Preferred examples are given below. (1) Examples of polyglycidyl ethers of polyhydric phenols Bisphenol-type diglycidyl compounds synthesized from one of bisphenol A, bisphenol F, bisphenol AD, and tetrabromobisphenol A and epihalohydrin, phenol novolak, and resorcinol. (2) Examples of polyglycidyl esters of polycarboxylic acids Diglycidyl ester of phthalic acid, diglycidyl ester of tetrahydrophthalic acid, hexahydrophthalic acid, etc. Diglycidyl ester of acid, diglycidyl ester of adipic acid, etc. (3) Examples of alicyclic epoxy compounds Vinylcyclohexene oxide, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 34-epoxy-
6-Methylcyclohexylmethyl-3,4-epoxy-6-epoxycyclohexanecarboxylate, 3,4-epoxyhexahydrobenzal-
3,4-epoxycyclohexane 1,1-dimethanol, bis(3,4-epoxy-6-methyl-
cyclohexylmethyl)adipate, bis(3,
(4-Epoxycyclohexylmethyl) adipate, etc. (4) Examples of polyglycidyl-ter of polyhydric alcohols: ethylene glycol, propylene glycol,
Glycerin, 1,4-butanediol, hydrogenated bisphenol A, polyethylene glycol, polyglycidyl compounds of polypropylene glycol and epihalohydrin, etc. (5) Examples of polyglycidyl compounds of polyvalent amines Aniline, xylene diamine, p-aminophenol, 4,4-diaminodiphenylmethane,
Polyglycidyl compounds of 5,5-dimethylhydantoin and epihalohydrin, etc. The modified block copolymer of α,β-unsaturated glycidyl compound (hereinafter referred to as modified block copolymer) used as component (b) in the present invention is:
A block copolymer and/or a hydrogenated product thereof (hereinafter referred to as a block copolymer consisting of a polymer block A mainly composed of at least one vinyl aromatic compound and a polymer block B mainly composed of at least one conjugated diene compound) (referred to as unmodified block copolymer)
This is a modified block copolymer obtained by mixing .alpha.,.beta.-unsaturated glycidyl compound under heating. The block structure of the unmodified block copolymer, which is the starting material for the modified block copolymer, has the general formula A-B-A, A(-B-A) _o , B(-A-B) _o ,
(A-B) _o , (A-B) _n X [However, n in the formula is 2 to
An integer of 10, m is an integer of 3 to 7, and X represents a polyfunctional residue with m bonds] is suitable; It may be a mixture of different ratios. For applications requiring high heat resistance, weather resistance, and stability over time, it is preferable that 80% or more of the aliphatic double bonds in the conjugated diene compound be hydrogenated. The proportion of the constituent components of the unmodified block copolymer is 10 to 70% by weight, preferably 10 to 50% by weight of the vinyl aromatic compound. The structure of each polymer block A and B is a polymer block A mainly composed of a vinyl aromatic compound.
is a homopolymer block of vinyl aromatic compounds,
Alternatively, the polymer block B is composed of a vinyl aromatic compound containing a vinyl aromatic compound in an amount of 50% by weight or more, preferably 70% by weight or more, and a conjugated diene compound or a hydrogenated product thereof, and the polymer block B mainly consists of a conjugated diene compound. It consists of a homopolymer block of a compound or a conjugated diene compound or a hydrogenated product thereof containing 50% by weight or more, preferably 70% by weight or more of a conjugated diene compound or a hydrogenated product thereof, and a vinyl aromatic compound. Also,
These polymer block A mainly consists of a vinyl aromatic compound, and the polymer block B mainly consists of a conjugated diene compound or its hydrogenated product. The distribution of the conjugated diene compound and vinyl aromatic compound may be random, tapered (the monomer component increases or decreases along the molecular chain), partially block-like, or any combination of these. , if there are two or more polymer blocks mainly composed of the vinyl aromatic compound and two or more polymer blocks mainly composed of a conjugated diene compound or a hydrogenated conjugated diene compound, each polymer block has the same structure. or have a different structure. Examples of the vinyl aromatic compound constituting the unmodified block copolymer which is the starting material for the modified block copolymer of the present invention include styrene, α-methylstyrene, vinyltoluene, and p-tert-butylstyrene. One or more types can be selected from among them, and styrene is preferred among them. Examples of the conjugated diene compound or the conjugated diene compound before hydrogenation constituting the hydrogenated conjugated diene compound include butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, etc. One or more types are selected from the following, and among them, butadiene, isoprene, and a combination thereof are preferred. For a polymer block mainly composed of a conjugated diene compound or a conjugated diene compound before hydrogenation, the microstructure of the block can be arbitrarily selected. For example, in a polybutadiene block, a 1,2-vinyl bond structure is used. is 20~
50%, preferably 25-45%. Further, the number average molecular weight of the block copolymer having the above structure is 5,000 to 1,000,000, preferably 10,000 to
800,000, more preferably in the range of 15,000 to 500,000, and the molecular weight distribution [ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) (Mw/Mn)] is 10 or less. These block copolymers may be obtained by any manufacturing method as long as they have the above structure. For example,
According to the method described in Japanese Patent No. 23798, a vinyl aromatic compound-conjugated diene compound block copolymer can be synthesized in an inert solvent using a lithium catalyst. Further, as a method for producing a hydrogenated product of a vinyl aromatic compound-conjugated diene compound block copolymer that exhibits more preferable performance, for example, the method described in Japanese Patent Publication No. 42-8704 and Japanese Patent Publication No. 43-6636 is known. Although the method can be adopted,
In particular, hydrogenated block copolymers synthesized using titanium-based hydrogenation catalysts that exhibit excellent weather resistance and heat deterioration resistance of the resulting hydrogenated block copolymers are most preferred. −133203 Publication,
By the method described in Japanese Patent Application Laid-Open No. 60-79005,
The hydrogenated block copolymer used in the present invention can be synthesized by hydrogenation in the presence of a titanium-based hydrogenation catalyst in an inert solvent. At this time, at least 80% of the aliphatic double bonds based on the conjugated diene compound of the vinyl aromatic compound-conjugated diene compound block copolymer are hydrogenated, and the polymer block mainly composed of the conjugated diene compound is transformed into an olefin. The compound can be converted into a polymer block. In addition, hydrogen of an aromatic double bond based on a vinyl aromatic compound copolymerized into a polymer block A mainly composed of a vinyl aromatic compound and, if necessary, a polymer block B mainly composed of a conjugated diene compound. Although there is no particular restriction on the addition rate, it is preferable that the hydrogenation rate is 20% or less. The amount of non-hydrogenated aliphatic double bonds contained in the hydrogenated block copolymer can be easily determined using an infrared spectrophotometer, the magnetic resonance apparatus, or the like. The glycidyl-modified block copolymer obtained by modifying with an α,β-unsaturated glycidyl compound, component (b) of the present invention, is a glycidyl-modified block copolymer obtained by modifying one or more unmodified block copolymers with an α,β-unsaturated glycidyl compound. This is a modified block copolymer obtained by mixing and contacting an α,β-unsaturated glycidyl compound in the presence or absence of an organic peroxide and/or a solvent. Examples of α,β-unsaturated glycidyl compounds used for modification include glycidyl esters of α,β-unsaturated monocarboxylic acids, glycidyl esters of α,β-unsaturated dicarboxylic acids, and glycidyl ethers of α,β-unsaturated alcohols. It is an unsaturated monomer having a monoethylenically vinyl bond and an epoxy group in the same molecular chain, such as glycidyl acrylate,
Preferred are glycidyl methacrylate, alkyl glycidyl maleate, allyl glycidyl ether, and the like. The modified block copolymer is produced by mixing and contacting the raw material block copolymer with an α,β-unsaturated glycidyl compound under heating. Specifically, for example, a block copolymer or its hydrogenated product and an α,β-unsaturated glycidyl compound are added with an organic peroxide or an antioxidant, if desired, and then mixed into a tumbler, a Henschel mixer, etc. A good method is to mix the components in advance, and then extrude them using an extruder at a temperature above the softening temperature and below the decomposition temperature of the block copolymer, or knead them with a kneader, Banbury mixer, or the like. In addition, the raw material block copolymer is supplied to the extruder, and an α,β-unsaturated glycidyl compound is injected through the injection port provided on the cylinder wall between the feed port and the exit of the extruder, or is dropped into the feed hopper. You can also do something like this. Furthermore, if necessary,
A second monomer component such as styrene, methyl methacrylate, vinyl acetate, or vinyltriethoxysilane can also be coexisting during the mixing and contacting process, and this method allows for control of the reaction rate and further modification of the glycidyl-modified block copolymer. Useful for quality. Another method for producing modified block copolymers is to dissolve or disperse the block copolymer or its hydrogenated product in an inert solvent such as toluene or methyl ethyl ketone, which has a relatively low decomposition temperature. A method in which an organic peroxide and an α,β-unsaturated glycidyl compound are added and brought into contact with stirring is also preferred. In glycidyl modification in the presence of a solvent, a mixed solvent system containing ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone may suppress side reactions based on ring opening of glycidyl groups, and has the effect of preventing gelation. There is. Next, it is more preferable that the α,β-unsaturated glycidyl compound is grafted onto the unmodified block copolymer which is the starting material, and the grafting ratio is as follows with respect to the modified block copolymer:
A content of 0.01 to 30% by weight or less, especially 0.03 to 15% by weight gives good results. If it exceeds 30% by weight, not only can no longer be expected to achieve quantitative effects, but also tends to cause undesirable side reactions such as gelation. Also
If it is less than 0.01% by weight, the effect is only the same as that of an unmodified block copolymer, and the modifying effect is not sufficient. The presence or absence of grafting can be easily confirmed by purifying the modified block copolymer by extruding it with a solvent such as acetone, and then analyzing it with an infrared spectrophotometer or magnetic resonance apparatus. can. The proportion of the epoxy resin having two or more epoxy groups in one molecule and the modified block copolymer in the composition of the present invention is 2 to 100 parts by weight per 100 parts by weight of the epoxy resin.
parts by weight, and may contain an unmodified block copolymer which is a starting material for the modified block copolymer, or an unmodified block copolymer having a different structure or composition. When the unmodified block copolymer is used in common, the mixing ratio of the unmodified block copolymer and the modified block copolymer is 0 to 0.
95% by weight, modified block copolymer 100-5% by weight
can be arbitrarily selected from the range. The method of mixing the epoxy resin with the modified block copolymer and unmodified block copolymer (hereinafter referred to as block copolymers) is not particularly limited, but may be mixed using a kneader, extruder, heated roll, etc. It is best to use a solvent and stir to create a homogeneous solution. In addition, an epoxy resin can be dissolved in a solvent that is a good solvent for epoxy resins and a poor solvent for block copolymers, such as ketones or acetic esters, and then dissolved in toluene or the like with stirring. When the copolymers are added dropwise, an epoxy resin composition in which the block copolymers are finely dispersed can be obtained. In this case, the dispersed particle size of the block copolymers is such that the block copolymer or its hydrogenated product is dispersed in the epoxy resin matrix in the cured product that is the final use form, and the average Particle size is 0.01-30μm, preferably 0.05
The size is preferably ~20 μm, more preferably 0.1 to 10 μm. If it exceeds 30 μm, it is not preferable because the impact resistance improvement effect decreases or it causes blistering when immersed in water or heated at high temperatures. Obtaining a particle size of less than 0.01 μm is extremely difficult, and at the same time, the improvement effect has already reached saturation, so it is not very meaningful. In addition, the solvent is removed by distillation under reduced pressure from a solution of an epoxy resin composition obtained by mixing epoxy resins that are liquid at room temperature in the presence of a solvent, and a block copolymer containing substantially no solvent is obtained. The combined dispersion liquid epoxy resin composition is suitable for use as an epoxy resin material for casting. When using the present invention, a curing agent for epoxy resin is added for practical use. The curing agent that can be used is not particularly limited, and generally known curing agents can be used. The amount of curing agent used is 0.5 to 0.5 of the sum of the amounts of epoxy groups contained in each of component (a) and component (b).
2.0 times stoichiometric amount is preferred. Specific examples below include (1) Examples of aliphatic, alicyclic or aromatic amines: ethylenediamine, hexamethylenediamine,
N,N,N-trimethylhexamethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, N,N-dimethylpropylenediamine, N,N-diethylpropylenediamine, 2,2-bis(4-aminocyclohexyl)propane , 5,5-dimethyl-3-
Aminomethyl-cyclohexylamine, 2,4,
6-tris(dimethylaminomethyl)phenol, m-phenylenediamine, p-phenylenediamine, bis(4-aminophenyl)methane, bis(4-aminophenyl)sulfone, m-xylylenediamine, piperidine, monoethanolamine, etc. . (2) Examples of acid anhydrides Phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyl-tetrahydrophthalic anhydride, methyl-hexahydrophthalic anhydride, 3,6-endomethylene-tetrahydrophthalic anhydride, succinic anhydride acid, polyadipic anhydride,
Polyazelaic anhydride, dodecenylsuccinic anhydride, trimellitic anhydride, trimellitic anhydride, etc. (3) Examples of other curing agents Adducts of the various amines listed in (1) with monoepoxy compounds such as ethylene oxide or propylene oxide, adducts with bisphenol A type epoxy resin, addition condensation of phenol and formalin unsaturated fatty acids such as linoleic acid and linoleic acid.
dicyandiamide, benzyldimethylamine, imidazole and various imidazole derivatives, such as 2-methylimidazole, 2-ethyl-4-methyl-imidazole, etc., acid hydrazides such as adipic acid dihydrazide and sebacic acid dihydrazide, Boron trifluoride-amine complex compounds, etc. When using the present invention, curing accelerators, fillers, pigments, diluents, extenders, organic solvents, plasticizers, flame retardants, mold release agents, lubricants, etc. can be added as necessary. To use the present invention, a curing agent and other materials as necessary are added to a previously prepared composition consisting of an epoxy resin and modified block copolymers, and the mixture is uniformly mixed to produce a compounded product. Depending on the desired shape, it may be cured at any temperature ranging from room temperature or lower to 200° C. or higher for a period of several minutes to several days. Generally, these curing conditions are determined by the epoxy resin and curing agent used and are not significantly affected by the modified block copolymers. [Effects of the Invention] The epoxy resin composition of the present invention has improved adhesion, excellent impact resistance, thermal shock resistance, heat deterioration resistance, water resistance, and solvent resistance, and is also resistant to heating and immersion in water. It has the effect of not causing foaming or reducing adhesive strength, and having an excellent appearance with almost no coloration. Therefore, not only adhesives and paints, but also electrical insulating materials such as insulators, bushings, printed wiring boards, IC sealing materials, etc.
It is useful for a wide range of applications, including composite materials containing carbon fiber, glass fiber, glass beads, mica, etc. [Examples] The present invention will be described in more detail with reference to Examples below, but the present invention is not limited thereto. Note that % and parts are based on weight. Reference example: Production of glycidyl-modified block copolymer 100 parts of a block copolymer having a styrene polymer block and a butadiene polymer block shown in Table 1 or a hydrogenated product thereof, and 2,
Mix 5-dimethyl-2,5-di(tert-butylperoxy)hexane well in a tumbler or Henschel mixer, and mix it in a 30 mm container set at 200-260℃.
The glycidyl methacrylate shown in Table 1 was injected from the first vent located at the end of the first stage compression zone to obtain a glycidyl-modified block copolymer. The amount of glycidyl methacrylate added to the block copolymer by grafting was as shown in Table 1. In addition, these remained transparent with almost no coloration even after glycidyl modification, whereas when maleic anhydride was used in place of glycidyl methacrylate at the same blending ratio as A in Table 1, The maleic anhydride-modified block copolymer obtained had a 2.0 times higher amount of maleic anhydride added through grafting, but was colored deep yellowish brown.

[Table] Additives *2) Glycidyl methacrylate Examples 1 to 4 20 parts each of glycidyl modified block copolymers A to D obtained in reference examples and Asahi epoxy resin AER661R
(Epoxy equivalent: 450-500, manufactured by Asahi Kasei Industries) were well kneaded using a Brabender Plastograph, the resulting kneaded product was transferred to an open roll at 60°C, and all epoxy groups (epoxy resin and glycidyl-modified dicyandiamide in an equivalent amount to the total amount of glycidyl groups contained in the block copolymer,
7% benzyldimethylamine of dicyandiamide was added and kneaded for 10 minutes to obtain an epoxy resin composition. Next, these were transferred to a 100℃ heat press machine, sandwiched between Teflon sheets, and preheated for 5 minutes.
Pressure (50 Kgf/cm ² ) was applied for 1 minute to obtain an uncured sheet with a thickness of 0.2 mm. This sheet was sandwiched between 0.2 mm thick soft aluminum plates cleaned with toluene, compressed (pressure 20 Kgf/cm ² ) until the thickness of the epoxy resin composition layer became 0.1 mm, and held at 190°C for 15 minutes. A bonded laminate was obtained. Test pieces with a width of 25 mm were cut from this adhesive laminate, and the T-peel strength was measured at a tensile rate of 200 mm/min at temperatures of 23°C and 120°C. The results are shown in Table 2. In addition, the uncured sheet was placed between 0.6 mm thick chemically treated steel plates so that the adhesive surface was 25 mm wide.
mm, and the length is 15 mm, and the epoxy resin composition layer is compressed (pressure
20Kgf/cm ² ) and held at 190°C for 15 minutes to obtain a test piece for tensile shear test. Tensile shear rate 2mm/
Its strength was measured at temperatures of 23°C and 120°C. The results are shown in Table 2. Comparative Examples 1, 2 Glycidyl-modified block copolymer A of Example 1
An uncured sheet was prepared using the unmodified block copolymers as starting materials and D in the same manner and blending ratio as in Example 1, and an adhesive laminate and a test piece were obtained in the same manner as in Example 1. Next, the T-peel strength and tensile shear strength were determined under the same conditions as in Example 1. The results are shown in Table 2. Comparative Example 3 Glycidyl-modified block copolymer A of Example 1
Instead of, liquid terminal carboxylated 1,2-polybutadiene (NISSO-PBC-1000 manufactured by Nippon Shodatsu)
An adhesive was prepared in the same manner as in Example 1, except that the adhesive was used, and the same tests as in Example 1 were conducted. The results are shown in Table 2. Comparative Example 4 Using the epoxy resin AER661R used in Example 1 alone, using the same type of curing agent as in Example 1, and using the same formulation as in Example 1 using a Brabender plastograph at 60 ° C. After kneading for 15 minutes, an uncured sheet was obtained using a hot press at 80°C.
This product was adhered in the same manner as in Example 1, and tested in the same manner as in Example 1. The results are shown in Table 2.

[Table] From the results in Table 2, it can be seen that the epoxy resin composition of the present invention has improved adhesive properties.
In particular, compositions containing glycidyl-modified block copolymers of hydrogenated block copolymers (Example 1 to
3) also has excellent heat resistance. Example 5 A liquid epoxy resin with an epoxy equivalent of 189 and a viscosity of 14,000 CPS at 25°C (AER331 manufactured by Asahi Kasei Corporation) and the glycidyl-modified block copolymer A of the reference example were mixed into a third resin.
It was prepared according to the following procedure so as to have the proportions shown in the table. First, put an epoxy resin and a small amount of toluene/tetrahydrofuron mixture in a container, and while stirring using a homogenizer, mix 10-30% of the glycidyl-modified block copolymer and the unmodified block copolymer.
% toluene solution was added, and toluene and tetrahydrofuran were added so that the total concentration of the epoxy resin and block copolymer was 50%, and mixed uniformly. This mixed solution was transferred to a rotary evaporator (manufactured by Tokyo Rika Kikai) and heated at 60°C/60 rpm.
Toluene and tetrahydrofuran were distilled off under reduced pressure while stirring at 150° C. for 1 hour until the volatile content became 0.3% or less. To the obtained composition, an equivalent amount of triethylenetetramine was added to the total epoxy groups (the total amount of glycidyl groups contained in the epoxy resin and the glycidyl-modified block copolymer), and the mixture was further incubated at 80°C for 3 hours at room temperature. Izot impact strength of the cured product cured for 7 days (according to JIS K-6911), average dispersed particle diameter of the block copolymer measured by electron microscope, and weight when immersed in methyl ethyl ketone (3 days at room temperature) We looked at the rate of increase. The results are shown in Table 3. Comparative Example 5 The epoxy resin of Example 5 was used alone, and the properties of the cured product obtained by curing in the same manner as in Example 5 with the same type of curing agent and formulation as in Example 5 were evaluated using the same method as in Example 5.・Examined the conditions. The results are shown in Table 3. Comparative Example 6 100 parts of the epoxy resin of Example 5 and 20 parts of the maleic anhydride-modified block copolymer obtained in Reference Example were mixed.
A composition containing no curing agent was prepared using the same procedure and method as in Example 5, and the properties of the cured product obtained by curing in the same manner as in Example 5 using the same type of curing agent and formulation as in Example 5 were evaluated. The investigation was conducted according to Example 5. The results are shown in Table 3. Comparative Example 7 100 parts of the epoxy resin of Example 5 was mixed with 20 parts of a liquid acrylonitrile-butadiene copolymer with carboxylated terminals on both ends and 12 parts of triethylenetetramine as a curing agent, and the same procedure as in Example 5 was carried out. The Izot impact strength of the obtained cured product and the weight increase rate due to methyl ethyl ketone immersion were investigated. The results are shown in Table 3.

[Table] As can be seen from Table 3, the epoxy resin composition of the present invention has excellent impact resistance and the weight increase rate when immersed in methyl ethyl ketone is lower than that of the maleic anhydride-modified block copolymer with the same blending standard and that of the maleic anhydride-modified block copolymer with carboxylated at both ends. The chemical resistance was lower than that of an epoxy resin composition using an acrylonitrile-butadiene copolymer. Example 6 The glycidyl-modified block copolymer obtained in Reference Example A was pulverized by a freeze-pulverization method or a spray ring operation method to obtain a powder having an average diameter of 60 μm and 20 μm. 20 parts of this powder was dispersed in 100 parts of the epoxy resin used in Example 5, and a cured product of the epoxy resin composition was obtained using the curing agent, compounding criteria, and curing conditions shown in Example 5. When the Izot impact strength of these polymers was measured, it was found that the average diameter of the glycidyl-modified block copolymer was
In the case of 60μm, the value is 3.3Kg・cm/cm, and in the case of 20μm, the value is 4.1Kg・cm/cm, and when combined with Table 3,
It can be seen that there is a preferable range for the particle size of the glycidyl-modified block copolymer in the cured product. Example 7, Comparative Examples 8 and 9 Cured product of an epoxy resin composition containing 20 parts of glycidyl-modified block copolymer per 100 parts of the epoxy resin of Example 5 (Example 7) and maleic anhydride of Comparative Example 6 A cured product of an epoxy resin composition containing a block copolymer (Comparative Example 8) and a cured product of an epoxy resin composition containing a carboxylated acrylonitrile-butadiene copolymer at both ends of Comparative Example 7 (Comparative Example 9) were heated at 150°C. JIS K 6911 with 1000 hours retention
The flexural modulus was measured according to . In addition, changes in appearance were observed after holding at 230°C for 2 hours. The results are shown in Table 4.

[Table] As shown in Table 4, the epoxy resin composition of the present invention has a higher initial elastic modulus than that of Comparative Example 9, which contains the acrylonitrile-butadiene copolymer with carboxylation at both ends, but when maintained at a high temperature. There is little change in the properties of the copolymer, and unlike the case of Comparative Example 8 containing the maleic anhydride-modified block copolymer, there is no appearance change such as blistering even when exposed to higher temperatures, and it has excellent flexibility. Has heat resistance. Example 8 17% of a blend of 33% glycidyl-modified block copolymer B obtained in Reference Example and 67% unmodified block copolymer (raw material block copolymer for glycidyl-modified block copolymer) toluene solution 60
and 40 parts of an epoxy resin (used in Example 5) with an epoxy equivalent of 189 were mixed with a homogenizer until a uniform cloudy mixture was obtained, and 2.5 times more piperidine was added as a hardening agent to form a 0.4 mm thick mixture. It was applied onto a chemical conversion treated steel plate using a film applicator so that the dry film thickness was 10 μm. This was transferred to a dryer at 110°C and held for 30 minutes to dry and precure, and a separately prepared film of the maleic anhydride-modified block copolymer obtained in the reference example with a thickness of 50 μm was used as a core layer. The block copolymer coated surface was placed on top of the film to form an adhesive surface, and the rolls were crimped at a linear pressure of 5 kg/cm using rolls heated to 160°C with a roll spacing of 0.85 mm.
It was cured for 10 hours at ℃. The obtained sandwich steel plate has a tensile shear strength at room temperature of 90Kg/cm ² and a T-peel strength at room temperature of 10.5Kg/25
mm, and not only can withstand punching and bending processes, but when tested for water resistance by immersing it in water at 40℃, it maintained almost the same strength as the initial adhesive strength even after 14 days. The vibration damping properties near room temperature were also excellent.

Claims (1)

[Scope of Claims] 1. A polymer block A consisting mainly of (a) 100 parts by weight of an epoxy resin having two or more epoxy groups in one molecule, and (b) at least one vinyl aromatic compound.
and a polymer block B mainly composed of at least one conjugated diene compound, and/or a glycidyl-modified block copolymer obtained by modifying a hydrogenated product thereof with an α,β-unsaturated glycidyl compound. An epoxy resin composition comprising 2 to 100 parts by weight of a combination. 2 The block copolymer and/or its hydrogenated product is composed of a polymer block A mainly composed of styrene and a polymer block B mainly composed of butadiene or isoprene.
B-A) _o , B(-A-B) _o , (A-B) n, (A-
B) Block copolymer represented by mX [wherein n is an integer of 2 to 10, m is an integer of 3 to 7, and X represents a polyfunctional residue having m bonds] The epoxy resin composition according to claim 1, which is a hydrogenated product thereof. 3. The epoxy resin composition according to claim 1, wherein the block copolymer and/or its hydrogenated product contains 10 to 70% by weight of styrene as a polymer constituent and has a number average molecular weight of 5,000 to 500,000. 4 α,β-unsaturated glycidyl compound is α,β-
The epoxy resin composition according to claim 1, which is at least one glycidyl ester of an unsaturated carboxylic acid or a glycidyl ether of an α,β-unsaturated alcohol. 5 The α,β-unsaturated glycidyl compound is glycidyl acrylate, glycidyl methacrylate,
The epoxy resin composition according to claim 1, which is at least one of alkyl glycidyl maleate and allyl glycidyl ether. 6 The glycidyl-modified block copolymer is combined with the block copolymer and/or its hydrogenated product, α,
The epoxy resin composition according to claim 1, which is a modified block copolymer obtained by mixing and contacting a β-unsaturated glycidyl compound with heating in the presence or absence of an organic peroxide and/or a solvent. . 7 Modification in which the glycidyl-modified block copolymer contains an α,β-unsaturated glycidyl compound grafted to the block copolymer and/or its hydrogenated product in a proportion of 0.01 to 30% by weight based on the total amount of the modified product. The epoxy resin composition according to claim 1, which is a block copolymer. 8. The epoxy resin composition according to claim 1, wherein the modified block copolymer is present in a dispersed state in the epoxy resin, and the average diameter of the dispersed particles is 0.01 to 30 μm.