JPH0480051B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for producing a cured epoxy product that is used as a molding material, adhesive, paint, etc. for electronic and electrical parts, and more specifically, a method for producing a cured epoxy product that has excellent flexibility. Regarding. [Prior Art] Conventionally, epoxy resins typically produced by the reaction of bisphenol A and epichlorohydrin have high mechanical strength in molded products, and have excellent water resistance, chemical resistance,
It is used heavily in various materials because of its excellent electrical insulation properties. However, this epoxy resin has the disadvantage that it is too hard and has no flexibility, and is easily broken by impact. For this reason, various improvements have been attempted, such as adding rubber components or changing the type of curing agent. However, since these conventional improvement methods involve blending and adding other components, the original excellent properties of the epoxy resin may be lost. [Problems to be Solved by the Invention] An object of the present invention is to provide a method for producing a cured epoxy body having excellent flexibility, which overcomes the above-mentioned problems. [Means for Solving the Problems] The method for producing a cured epoxy product of the present invention involves combining a diene monomer and an epoxy group-containing monomer in the presence of a polymerization initiator and/or chain transfer agent capable of introducing a hydroxyl group. It is characterized in that a copolymer obtained by polymerization and having a hydroxyl group and an epoxy group in the molecule is cured with a curing agent for epoxy resin. The diene monomer is not particularly limited, but usually a diolefin-based unsaturated unsubstituted, 2-substituted, or 2,3-substituted 1,3-diene having 4 to 12 carbon atoms is used. Examples of the substituent here include an alkyl group, an aryl group, a halogen, a cyano group, and a nitro group. Specific monomers include 1,3-butadiene, isoprene, 1,
3-pentadiene, chloroprene, 2,3-dichlorobutadiene, 2-cyano-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, etc. are used. The epoxy group-containing monomer is not particularly limited, but unsaturated glycidyl esters such as glycidyl acrylate, glycidyl methacrylate, and allyl glycidyl ether are used. The polymerization initiator and/or chain transfer agent capable of introducing a hydroxyl group into the copolymer is not particularly limited, but includes δ,δ'-azobis(δ-cyano)-n-
Azo compounds with hydroxyl groups such as pentanol,
A mixture of an azo compound such as 2,2'-azobisisobutyronitrile and a mercaptoalkanol such as mercaptoethanol, hydrogen peroxide, etc. are used. Among these, hydrogen peroxide is preferred. The blending ratio of the diene monomer and the epoxy group-containing monomer is not particularly limited, but usually the epoxy group-containing monomer is used in an amount of 50 to 2% by weight to 50 to 98% by weight of the diene monomer. The copolymer used in the present invention is basically obtained by copolymerizing a diene monomer and an epoxy group-containing monomer, but if necessary, a part of the diene monomer may be replaced with an ethylenically unsaturated monomer. An α-olefin addition polymerizable monomer having 2 to 22 carbon atoms is used instead. Specifically, styrene, α-methylstyrene, vinyltoluene, methyl methacrylate, acrylic acid, vinyl chloride, vinylidene chloride, acrylonitrile, acrylamide, 2-ethylhexyl acrylate, n-octadecyl acrylate,
These include maleic anhydride, butene, and 2-hydroxyethyl methacrylate. Although the polymerization reaction does not particularly require a solvent, it is usually preferably carried out in a solvent such as alcohol, a mixture of alcohol and water, ether, ketone, aliphatic hydrocarbon, aromatic hydrocarbon, or halogenated hydrocarbon. Such solvents include methanol,
Examples include ethanol, n-propanol, isopropanol, butanol, propyl ether, tetrahydrofuran, ethyl acetate, cellosolve, cellosolve acetate, ethyl cellosolve, acetone, and mixtures thereof. The amount of solvent used is not particularly limited, but usually the total amount (monomer, solvent,
5 to 500% by weight of hydrogen peroxide, etc.), preferably 30% by weight
~300% by weight. When hydrogen peroxide is used as an initiator, there are no particular restrictions, but hydrogen peroxide usually
0.1 to 50 parts by weight per 100 parts by weight, preferably
0.3 to 30 parts by weight are used. Hydrogen peroxide is usually
It is used as a 30-80% aqueous solution, preferably about 50% aqueous solution. Polymerization reaction conditions vary depending on the type of diene monomer used, the amount used, etc., and cannot be unambiguously specified, but are usually under stirring, at a reaction temperature of 50 to 200°C,
Preferably 80~150℃, reaction pressure 0~200Kg/ ^cm2
G, preferably 1 to 100 Kg/cm ² G for 0.1 to 24 hours,
Preferably by reacting for 0.2 to 20 hours,
A liquid copolymer having a hydroxyl group and an epoxy group in the molecule can be produced. This copolymer preferably has an average number of functional hydroxyl groups of 1.0 or more. It is thought that the hydroxyl group present in the molecule acts as a curing accelerator during the subsequent curing treatment. The copolymer used in the present invention has, for example, the following structure. (Here, R is a methyl group or hydrogen, a and b represent the ratio of structural units in the copolymer, and are positive decimal numbers that add up to 1. n is a positive decimal that represents the degree of polymerization of the copolymer. In number, n = 5 to 500, preferably 10 to
It is 200. ) The copolymer thus obtained is cured using a common curing agent for epoxy resins, optionally in the presence of a curing accelerator, to obtain a cured epoxy product. The curing agent for epoxy resins is not particularly limited, but polyamines, polyamides, dibasic acids or their anhydrides, etc. are usually used. Specifically, the polyamines include diethylenetriamine, triethylenetetramine, imidazole, metaphenylenediamine, diaminodiphenylmethane, etc., and the polyamides include polyamide oligomers produced by the condensation reaction of dimer acid and polyamines.
Dibasic acids or anhydrides include phthalic acid or anhydride, hexahydrophthalic acid or anhydride, methyl 3,6-endo-methylene-δ ⁴ -tetrahydrophthalic acid or methyl 3,6-anhydride. Examples include endo-methylene-δ ⁴ -tetrahydrophthalic acid, pyromellitic acid, and pyromellitic anhydride. The curing agent for epoxy resin is not particularly limited, but
It is usually added in an amount of 5 to 200 parts by weight per 100 parts by weight of the copolymer. The curing accelerator is not particularly limited, but includes, for example, tertiary amines such as triethylenediamine, benzyldimethylamine, triethanolamine, dimethylethanolamine, dimethylaminoethanol, and tri(dimethylaminomethyl)phenol, 2-methylimidazole, Imidazoles such as 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-heptadecyl imidazole, tributylphosphine, methyldiphenylphosphine, diphenylphosphine, triphenylphosphine, phenylphosphine, etc. organic phosphines, tetraphenol phosphionium tetraphenylborate, 2-ethyl-4
Examples include tetraphenyl boron salts such as methylimidazole tetraphenyl borate. The curing accelerator is not particularly limited, but usually based on the total amount of the copolymer and the curing agent for epoxy resin,
It is used in an amount of 0.01 to 10% by weight, preferably 0.05 to 5% by weight. The curing reaction is carried out at 0-200°C, preferably 20-160°C. The copolymer of the present invention may also contain an inorganic filler, a mold release agent, a coloring agent, a coupling agent, and the like, if necessary. [Examples] The present invention will be explained below with reference to Examples, but the scope of the present invention is not limited to these Examples. Table 1 shows the conditions for producing copolymers of Examples and Comparative Examples of the present invention, and the results of measuring various properties of the copolymers. Table 2 shows the formulation, curing conditions, and physical properties of the epoxy cured products of Examples and Comparative Examples of the present invention. [Production example of copolymer] Production examples 1 to 5 The ingredients shown in the proportions shown in Table 1 were charged into a stainless steel pressure-resistant container equipped with a stirrer, and after raising the temperature for 60 minutes, polymerization was carried out under the conditions shown. I went. After that, air is blown onto the outer surface of the container to lower the temperature.
The indicated post-treatments were carried out to obtain a copolymer. Production Examples 6 to 8 The temperature was raised for 30 minutes, 0.05 parts by weight of 4-t-
A copolymer was obtained by carrying out the reaction in the same manner as in Production Examples 1 to 5, except that 1 part by weight of toluene containing butylcatechol was added to stop the polymerization. In addition, the numerical values in the table mean parts by weight unless otherwise stated. [Manufacture of epoxy cured product] Stir and mix the indicated ingredients in the proportions shown in Table 2,
A cured product was obtained by curing treatment under the indicated curing conditions.

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Claims (1)

[Claims] 1 obtained by copolymerizing a diene monomer and an epoxy group-containing monomer in the presence of a polymerization initiator and/or chain transfer agent capable of introducing a hydroxyl group,
A method for producing a cured epoxy product, which comprises curing a copolymer having a hydroxyl group and an epoxy group in the molecule with a curing agent for epoxy resin.