JP2715512B2 - Epoxy resin composition and molded article obtained by curing the same - Google Patents

Description

The present invention relates to a novel and useful epoxy resin composition and an article using the same.
The present invention relates to a resin composition using an epoxy resin obtained by reacting 4'-dihydroxybenzophenone and epichlorohydrin, and a molded article excellent in heat resistance and toughness.

(Prior art) Epoxy resins are generally cured with various curing agents to provide mechanical properties, water resistance, chemical resistance, heat resistance,
Excellent cured products such as electrical properties, adhesives, paints,
It is used in a wide range of fields such as laminates, molding materials, and casting materials.

The most versatile epoxy resins are liquid and solid bisphenol A epoxy resins obtained by reacting epichlorohydrin with bisphenol A, which give cured products with excellent toughness, but have a glycidyl group per molecule. Since there are no more than two, the crosslink density is low and the cured product tends to be inferior in heat resistance.

In order to improve such disadvantages, a so-called polyfunctional epoxy resin, such as a novolak type epoxy resin, is used.In these cases, although the heat resistance is certainly improved, the cured product is brittle and the toughness is low. Has disadvantages.

(Problems to be Solved by the Invention) An epoxy resin having both the toughness of a bisphenol A type epoxy resin and the heat resistance of a novolak type epoxy resin has been developed. However, a cured product having both these two properties is provided. There is no epoxy resin composition. In addition, development of an epoxy resin composition having more excellent heat resistance is desired.

(Means for Solving the Problems) In view of these circumstances, the present inventors have sought a epoxy resin composition having better heat resistance than a novolak type epoxy resin and as tough as a bisphenol A type epoxy resin. As a result of extensive research, an epoxy resin having an epoxy equivalent of 163-1350 obtained by reacting epichlorohydrin with 4,4'-dihydroxybenzophenone was an essential component,
It has been found that a resin composition obtained by blending a curing agent with the epoxy resin component and, if necessary, a curing accelerator further has the characteristics as described above, and to complete the present invention. It has arrived.

That is, the present invention provides an epoxy resin composition comprising an epoxy resin, a curing agent, and, if necessary, a curing accelerator, wherein the epoxy resin component comprises 4,4′-
An epoxy resin composition containing an epoxy resin having an epoxy equivalent of 163-1350 obtained by reacting dihydroxybenzophenone and epichlorohydrin, and a molded article obtained by curing the epoxy resin composition.

The epoxy resin used in the present invention is 4,4'-dihydroxybenzophenone, that is, the structural formula [I] Can be easily obtained by reacting epichlorohydrin with a compound represented by the formula in the presence of a base.

The reaction conditions in this case are the same as the conventional conditions for producing an epoxy resin, and are not particularly limited. For example, 1.4 to 20 mol of epichlorohydrin is added to 1 mol of 4,4'-dihydroxybenzophenone, and epoxidation can be carried out at 20 to 120 ° C for 2 to 7 hours in the presence of a base.

The base used in the epoxidation is not particularly limited, but examples include potassium hydroxide, sodium hydroxide, potassium carbonate, and sodium carbonate.

The epoxy resin obtained as described above usually has the general formula (II), [N represents 0 to 1.3, preferably 0.9. ] It contains the epoxy resin shown by these as a main component. The molecular weight, epoxy equivalent, and softening point of the obtained epoxy resin can be adjusted by adjusting the excess ratio of the mole number of epichlorohydrin to the mole number of 4,4'-dihydroxybenzophenone. Decreasing the excess of epichlorohydrin tends to increase the molecular weight of the epoxy resin and give a cured product with high toughness, while increasing it tends to give a cured product with a low molecular weight and high heat resistance. However, in general, when the excess ratio exceeds 8 times, it becomes difficult to obtain an epoxy resin which gives a cured product having more excellent heat resistance. Therefore, the excess ratio is desirably 10 times or less.

The epoxy resin thus obtained has an epoxy equivalent of
Although it is a thing of 163-350, it is preferable that an epoxy equivalent is 163-300 especially from the point which is excellent in heat resistance. Further, as will be described later, the composition of the present invention can further be used in combination with other known and commonly used epoxy resins, but in the present invention, the epoxy equivalent in all epoxy resins in the composition from the viewpoint of heat resistance. 163-350, furthermore 163-3
It is preferably 00.

The epoxy resin composition of the present invention can be easily prepared by mixing an epoxy resin obtained by reacting 4,4'-dihydroxybenzophenone with epichlorohydrin, a curing agent, and, if necessary, a curing accelerator by a known and common method. Can be obtained.

The curing agent used in the present invention is not particularly limited, and all compounds that are commonly used as curing agents for epoxy resins can be used, and diaminetriamine, aliphatic amines such as triethyltetramine,
Metaphenylenediamine, diaminodiphenylmethane,
Aromatic amines such as diaminodiphenyl sulfone, polyamide resins and modified products thereof, maleic anhydride, phthalic anhydride, hexahydrophthalic anhydride, acid anhydride-based curing agents such as pyromellitic anhydride, dicyandiamide, imidazole, BF Latent curing agents such as ₃ -amine complexes and guanidine derivatives.

The amount of the curing agent is not particularly limited,
The number of epoxy groups contained in one molecule of epoxy resin,
The amount in which the number of active hydrogen groups such as amino groups or imino groups, phenolic hydroxyl groups or the like or the number of acid anhydride groups in the curing agent is close to the equivalent is generally used.

When using each of the compounds as listed above as a curing agent,
In many cases, it is necessary to further use a curing accelerator, but in such a case, a tertiary amine such as dimethylbenzylamine, imidazoles, or various metal compounds and the like, a known and commonly used curing accelerator Of course, all can be used. The composition of the present invention, if necessary, further known and commonly used epoxy resins and fillers,
Various additives such as a coloring agent, a flame retardant, a release agent, and a silane coupling agent can be added and blended, and a tar, a pitch, an amino resin, an alkyd resin, a phenol resin, and the like can be used in combination.

Since the epoxy resin composition of the present invention is excellent in both heat resistance and toughness, it can be used in various fields such as prepregs, laminates, paints, adhesives, structural materials, molding materials and casting materials.

For example, the epoxy resin composition of the present invention can be heated and cured while maintaining an arbitrary shape to obtain various molded products having both heat resistance and toughness.

(Examples) Next, the present invention will be specifically described with reference to Production Examples, Examples, and Comparative Examples. In the following, all parts are by weight unless otherwise specified.

Production Example 1 214 g (1 mol) of 4,4'-dihydroxybenzophenone
Was dissolved in 740 g (8 mol) of epichlorohydrin,
440 g (2.2 mol) of a 20% aqueous NaOH solution was added dropwise over 5 hours at 80 ° C. with stirring, and the reaction was further performed for 1 hour. After discarding the aqueous layer, the excess epichlorohydrin was recovered by distillation. 490 g of toluene was added and dissolved uniformly, 160 g of water was added and the mixture was washed with water, oil-water separated, water was removed from the oil layer by azeotropic distillation, filtration was performed, and toluene was further distilled off to obtain an epoxy equivalent. 310 g of epoxy resin (a) 180 was obtained.

Production Example 2 An epoxy equivalent of 19 was obtained in the same manner as in Production Example 1 except that the amount of epichlorohydrin used was changed to 324 g (3.5 mol).
305 g of epoxy resin (b) 7 was obtained.

Production Example 3 214 g (1 mol) of 4,4'-dihydroxybenzophenone
With epichlorohydrin (231 g, 2.5 mol) and toluene 5
After dissolving in 4 g of the mixture, 440 g (2.2 mol) of a 20% aqueous NaOH solution was added dropwise at 80 ° C. over 5 hours with stirring at 80 ° C., and further reacted for 1 hour. After discarding the aqueous layer, excess epichlorohydrin was recovered by distillation. The reaction product obtained in
After adding 490 g and dissolving uniformly, adding 160 g of water and washing with water, separating oil and water, removing water from the oil layer by azeotropic distillation, filtering, and further distilling toluene, and epoxy having an epoxy equivalent of 208. 300 g of resin (c) was obtained.

Examples 1 to 3 and Comparative Examples 1 to 2 Epoxy resins (a) to (c) obtained in Production Examples 1 to 3 as epoxy resins, phenol novolak type epoxy resin EPICLON N-738 [Dainippon Ink Chemical Industry Co., Ltd. )
Epoxy equivalent 180] or bisphenol A type epoxy resin Epiclon 840 (manufactured by the company, epoxy equivalent 185), Epicron B-570 (manufactured by the company, methyltetrahydrophthalic anhydride), 2-ethyl- as a curing accelerator Using 4-methylimidazole, the epoxy resin of the present invention and a comparative epoxy resin were blended in a composition shown in Table 1 so that one epoxy group of the epoxy resin would have one acid anhydride group of the curing agent. A resin composition was obtained.

These epoxy resin compositions were cured at 100 ° C. for 2 hours, then at 160 ° C. for 2 hours, and further at 180 ° C. for 2 hours to obtain test specimens, and subjected to heat deformation temperature according to JIS K-6911,
Flexural strength, flexural modulus, tensile strength, tensile elongation and boiling absorption were measured. The results are shown in Table 1.

(Effect of the Invention) The epoxy resin composition of the present invention can provide a cured product having both the toughness of a conventional bisphenol A type epoxy resin cured product and the heat resistance of a novolak type epoxy resin cured product. Moreover, the heat resistance is superior to that of a cured novolak epoxy resin.

Therefore, the epoxy resin composition of the present invention can be used in various fields such as prepregs, laminates, paints, adhesives, structural materials, molding materials, and casting materials.

Claims (5)

(57) [Claims] 1. An epoxy resin composition comprising an epoxy resin, a curing agent and, if necessary, a curing accelerator, wherein an epoxy equivalent obtained by reacting 4,4'-dihydroxybenzophenone with epichlorohydrin as the epoxy resin component. An epoxy resin composition comprising 163 to 350 epoxy resins. 2. An epoxy resin composition comprising an epoxy resin, a curing agent and, if necessary, a curing accelerator, wherein the epoxy resin component comprises an epoxy resin represented by the general formula [II]. Epoxy resin composition. [N represents 0 to 1.3] 3. The composition according to claim 1, wherein the epoxy equivalent of all epoxy resin components in the composition is 163-1350. 4. A laminate obtained by curing the composition according to claim 1. 5. A molded article obtained by curing the composition according to claim 1.