JPS5837335B2 - Novel epoxy resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel solvent-free epoxy resin composition comprising a liquid epoxy resin and a liquid cyclopentadiene resin. This invention relates to a composition that has improved adhesive strength, coating adhesion, and workability without impairing its physical properties.

Epoxy resin is adhesive. Because it has excellent chemical resistance, oil resistance, corrosion resistance, and electrical properties, it is widely used in fields such as adhesives, injection molding, and painting.

However, epoxy resins are expensive; however, cheap diluents are usually used in combination with epoxy resins, and examples of such diluents include coumaron-indene resin, asphalt, and tar.

On the other hand, in order to conserve resources and energy, there has recently been a demand for solvent-free formulations that mainly use liquid epoxy resins or high-solvent formulations that contain a small amount of solvent in fields such as civil engineering, adhesives, and paints. However, if a solid diluent is blended with the epoxy resin in such a case, the viscosity of the system will increase extremely, resulting in a significant loss of workability.

Therefore, liquid diluents are attracting attention in order to overcome these drawbacks, but in general, liquid diluents have significantly lower mechanical and chemical properties than solid diluents. All diluents, such as petroleum-based and coal-based diluents, are not sufficiently compatible with epoxy resins and various hardening agents, and even when mixed with epoxy resins, they may affect the mechanical properties such as compressive strength of the molded product, and the adhesion. It has the disadvantage of reducing strength and chemical and oil resistance.

Therefore, at present, liquid diluents are hardly used in fields such as civil engineering, adhesives, casting, and paints.

Therefore, the present inventors conducted intensive studies to develop a new diluent that has physical properties equivalent to solid diluents and is suitable for solvent-free formulations. The inventors have discovered that the system resin is extremely excellent as a diluent for liquid epoxy resin, and have completed the present invention.

An object of the present invention is to provide a novel solvent-free epoxy resin composition that has improved adhesive strength, adhesion, and workability without impairing the inherent properties of the epoxy resin. (B) 85 to 35% by weight of a cyclopentadiene monomer and 15 to 65% by weight of a polar vinyl monomer copolymerizable with the cyclopentadiene monomer are heated as a diluent to a liquid epoxy resin. A copolymer obtained by polymerization or a hydrogenated copolymer obtained by hydrogenating the copolymer, with a viscosity at 25°C of ioo to 30,000.
This is achieved by blending a centipoise liquid cyclopentadiene resin, an effective amount of the curing agent (C), and, if desired, other commonly used blending agents.

The liquid cyclopentadiene resin used in the present invention is produced by mixing a cyclopentadiene monomer and a polar vinyl monomer copolymerizable with the monomer in benzene, toluene, etc. in the absence of a non-radical catalyst such as a cationic catalyst. , with or without an inert hydrocarbon solvent such as xylene.
At 300°C, preferably 230-280°C, 0.
It can be produced by heating polymerization in a pressure vessel for 5 to 20 hours, preferably 1 to 10 hours, and then separating it from low-boiling substances such as solid polymers and unreacted substances by means such as distillation.

The cyclopentadiene monomer used refers to cyclopentadiene or its derivatives, and specifically includes cyclopentadiene, alkyl-substituted cyclopentadiene such as methyl-substituted and ethyl-substituted cyclopentadiene, and dimers thereof; Examples include trimers and codimers, and mixtures thereof may also be used.

Since cyclopentadiene exists stably as dicyclopentadiene at room temperature, cyclopentadiene and dicyclopentadiene are usually handled in exactly the same way.

On the other hand, polar vinyl monomers copolymerizable with cyclopentadiene include allyl alcohol, crotyl alcohol,
1. Hydroxyl group-containing vinyl monomers such as 4-butenediol, hydroxyethyl acrylate, hydroxyethyl methacrylate: vinyl acetate, vinyl propionate, allyl acetate, methalyl acetate, allyl propionate, . Lower fatty acid esters of unsaturated alcohols such as metaallyl propionate; esters of unsaturated carboxylic acids such as acrylic acid, methacrylic acid, and lower alcohols such as methyl alcohol, ethyl alcohol, butyl alcohol; unsaturated cyanide compounds such as; unsaturated ethers such as allyl glycidyl ether; among others, lower fatty acid esters of hydroxyl group-containing vinyl monomers and unsaturated alcohols, particularly allyl alcohol and vinyl acetate, give excellent results.

The proportion of cyclopentadiene monomer and polar vinyl monomer used is 15% to 6% by weight of the latter based on the total amount of both.
It is in the range of 5% by weight, preferably in the range of 20 to 50% by weight. If it is less than 15% by weight, it will have poor compatibility with the epoxy resin and curing agent, and if it is blended with the epoxy resin, the physical properties of the cured product will deteriorate. This is not preferable because it lowers the

On the other hand, if it exceeds 65% by weight, the resulting liquid cyclopentadiene resin will be markedly colored and the cured product will have poor water resistance and solvent resistance, which is not preferred.

Further, in the present invention, among the liquid cyclopentadiene resins, those having a viscosity at 25° C. of 100 to 30,000 centipoise, preferably 1,000 to io, ooo centipoise are selectively used.

When using a resin with a viscosity exceeding 30,000 centipoise, the viscosity of the compound is too high, making it difficult to make it solvent-free and high solid, and the workability, castability, and smoothness of the coating film are poor. , ioo centipoise is undesirable because the physical properties of the cured product deteriorate.

In addition, in the present invention, a hydrogenated resin obtained by hydrogenating such a liquid cyclopentadiene resin by a conventional method can also be used. gives better results than other resins.

Although a wide variety of liquid epoxy resins can be used in the present invention, condensation reaction products of polyfunctional halohydrins and polyhydric phenols are generally commercially available.

Typical polyhydric phenols used in the production of epoxy resins include various bisphenols and low-molecular-weight phenolic aldehydes, which are condensation products of resorcinol or phenol with aldehydes or ketones such as formaldehyde, acetaldehyde, acetone, and methyl ethyl ketone. A typical epoxy resin is a reaction product of epichlorohydrin and bisphenol A, but the epoxy resin used in the present invention is not limited to those mentioned above. ，
All compounds having two or more epoxy groups in the molecule can be used in the present invention.

The blending ratio of the liquid cyclopentadiene resin in the present invention may be arbitrary as long as a normal diluent is used, but it is usually 60% by weight or less based on the total amount of the liquid cyclopentadiene resin and the liquid epoxy resin. However, if the liquid cyclopentadiene resin exceeds 60% by weight, it is not preferable because the properties originally possessed by the epoxy resin will be impaired.

Furthermore, in order to obtain a composition that has excellent adhesive properties and does not impair oil resistance, it is preferable that the proportion of liquid cyclopentadiene resin used is in the range of 5 to 50% by weight, more preferably 10 to 40% by weight. .

The epoxy resin composition of the present invention is suitable for applications such as civil engineering construction or structural adhesives, decorative articles, sealants, paints, etc. When used in such applications, liquid cyclopentadiene resin and In addition to liquid epoxy resins, known amines, amides, incyanate compounds, which are usually used as curing agents for epoxy resins,
An effective amount of acid anhydrides is used, and if desired, a resin having a polar group such as a hydroxyl group or an amine group, such as modified or unmodified phenol resin, urea resin, melamine resin, polyamide resin, etc., is used as a curing agent. You can also.

In addition, within the range that does not essentially impair the effects of the present invention,
In addition, reactive diluents such as alkyl glycidyl ethers, which are known as modifiers for epoxy resins, and modifiers such as solid cyclopentadiene resins can also be used. , inorganic fillers such as asbestos, various inorganic or organic pigments, etc. can be appropriately selected and used according to conventional methods.

The present invention will be explained in more detail with reference to Examples below.

Reference Example 1 Production of liquid cyclopentadiene resin 70 parts of dicyclopentadiene and comonomer 3 shown in Table 1
After bulk polymerizing 0 parts at 260°C for 3 hours in a pressure-resistant reaction vessel, unreacted monomers were removed from the resulting polymer mixture, and then polymerization was carried out at 200°C and 760 mmHj! , ■
200°C, 5mm}{,9, ■250'C, 5mm
Three types of liquid cyclopentadiene resins were obtained by sequential fractional distillation under Hg conditions.

Table 1 shows the viscosity of the obtained liquid cyclopentadiene resin at 25°C.

Reference Example 2 Hydrogenation of Liquid Cyclopentadiene Resin 100 parts each of liquid cyclopentadiene resins A-2 and A-3 copolymerized with allyl alcohol obtained in Reference Example 1 were placed in an autoclave, and stabilized nickel catalyst 1 was added. After reacting for 3 hours at a hydrogen pressure of 35 ky/cIrL and a temperature of 200°C, the residue of the hydrogenation catalyst was removed by filtration to obtain samples with viscosities of 1,800 and 11,000 centipoise at 25°C, respectively. AH-2 and AH-3 were obtained.

Example 1 Various cyclopentadiene resins obtained in Reference Examples or commercially available liquid diluent 3 were added to 70 parts of bisphenol A-epichlorohydrin type liquid epoxy resin (epoxy equivalent: 185).
0 parts and aromatic amine curing agent (amine value 120) 42
A cured molded product was obtained by blending the parts and leaving it at 25°C for 10 days.

The performance of this molded product is determined according to JISK6911 and JIS860.
40, and the results are shown in Table 2.

For comparison, performance was evaluated in the same manner when only 100 parts of epoxy resin and 60 parts of aromatic amine curing agent were blended.

The meanings of the symbols used in the evaluation of toluene resistance, etc. in Table 2 are as follows.

A: No change B: Whitening C: Compounds 1 to 6 affected
Comparison of the inventive example and the epoxy resin alone formulation of Formulation 15 shows that the shear adhesive strength of the inventive examples is improved without impairing mechanical properties, water resistance, and solvent resistance. I understand that.

However, if a resin with too low a viscosity is used (formulation 7
and 8) or when using a commercially available liquid diluent (Formulation 1
6 and 17), the mechanical properties were slightly lower and no improvement in adhesive strength was observed, and the cured products turned white and became brittle in terms of water resistance and solvent resistance.

In addition, when using a copolymer resin of a cyclopentadiene monomer and a nonpolar copolymerizable monomer (compounds 9 to 14)
Because it is not compatible with epoxy resin, it does not exhibit mechanical properties.
Moreover, in solvent resistance tests, it is unfavorable because it is extracted by solvents.

Example 2 AH- obtained in Reference Example 2 as a cyclopentadiene resin
2 was used, and the mixing ratio with the epoxy resin was varied to investigate the effect of the mixing ratio.

The epoxy resin and curing agent were the same as those used in Example 1, and the amount of curing agent used was constant with respect to the epoxy resin.

The results are shown in Table 3.

Example 3 Bisphenol A-epichlorohydrin type liquid epoxy resin (epoxy equivalent 185, Epicote 828, manufactured by Mitsubishi Yuka Co., Ltd.), liquid cyclopentadiene resin, solid cyclopentadiene resin, and butyl glycidyl ether were mixed in the proportions shown in Table 4. After measuring the viscosity at 25° C., an aromatic amine curing agent (amine value: 120) was added, and the cured physical properties were evaluated in the same manner as in Example 1.

The results are shown in Table 4.

These results show that when a solid cyclopentadiene resin is blended (Blend 22), the viscosity becomes high and workability is poor, and the effect of improving shear adhesive strength and peel strength is also insufficient. It can also be seen that even when a reactive diluent was used to adjust the viscosity (Formulation 23), the effect of improving adhesive strength was not sufficient.

Claims (1)

[Claims] 1 (AJ liquid epoxy resin, (B) 85 to 35% by weight of cyclopentadiene monomer and 15% by weight of polar vinyl monomer)
A copolymer obtained by thermal copolymerization of ~65% by weight or a hydrogenated copolymer obtained by hydrogenating the copolymer at 25°C.
A novel solvent-free epoxy resin composition comprising a liquid cyclopentadiene resin having a viscosity of ioo to 30,000 centipoise and (C) an effective amount of a curing agent. 2. The composition according to claim 1, wherein the proportion of the liquid cyclopentadiene resin is less than 60% by weight based on the total amount of the liquid epoxy resin and the liquid cyclopentadiene resin.