JPS61293216A - Epoxy resin curing agent - Google Patents

Abstract

PURPOSE:To epoxy resin curing agent having good compatibility with epoxy resins and a strong activity, obtained by the intermolecular dehydrohalogenation between a quat. phosphonium halide and a benzoic acid derivative and represented by the specified formula. CONSTITUTION:An epoxy resin curing agent comprising a phosphonium benzoate compound of the formula (wherein R1, R2, R3 and R4 are each alkyl, alkenyl, aryl, benzyl, cyanoethyl or hydroxymethyl, and R5 and R6 are each H, halogen, alkyl, amino, nitro, carboxyl, hydroxyl or cyano) as an effective component. Since this benzoate compound is a salt between a phosphonium cation as a strongly basic group and a benzoate anion as a weakly acidic group, it has an activity as an epoxy resin curing agent higher than that of a quat. phosphonium halide (its activity as an epoxy resin curing agent is well-known) as a neutral salt and it does not lose heat curability even when its pot life is markedly prolonged.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an epoxy resin curing agent containing a quaternary phosphonium benzoate compound as an active ingredient. The nuclear benzoate compound is obtained by intermolecular dehydrohalogenation of a quaternary phosphonium halide and a benzoic acid derivative, that is, the detailed reaction is synthesized according to the reaction shown by formula α).

[In formula (1), R1*R, I R1*R4 represents an alkyl group, an alkenyl group, an aryl group, a benzyl group, a Schiff/ethyl group, or a hydroxymethyl group, and -0R6 represents a hydrogen atom, a halogen atom, or an alkyl group.

Abano group, nitro group, carboxyl group, hydroxyl group, cyano group, and X also represents a halogen atom] The present inventors were interested in the reaction between quaternary phosphonium compounds and benzoic acid derivatives and conducted extensive research. As a result, we have arrived at the present invention.

That is, the quaternary phosphodiampenzoate compound according to the present invention differs from the generally-conceived quaternary phosphonium compound in that it contains a quaternary phosphonium cation as a cation component and a fluorocarboxyl anion in place of the halogen ion of the strong electrolyte as an anion component. It has unique properties by owning it.

The characteristics of this benzoate are described below.

1. Compared to general quaternary phosphonium halides, it is poorly soluble in water, but very well soluble in organic solvents and epoxy resins.

2. Decomposed with mineral acid and the constituent I! It is divided into quaternary phosphonium compounds and benzoic acid derivatives.

λ Stable to water and heat.

By utilizing the properties described above, we have obtained knowledge that the benzoate compound can be used as an epoxy resin curing agent.

It is a well-known fact that the quaternary phosphonium halide, which is the raw material for the benzoate compound, acts as an epoxy resin curing agent, but this quaternary phosphonium halide has a hydrophilic halogen ion as an anion component. Because of this, it has poor compatibility with epoxy resins, and also has the disadvantage that halogen ions, which are strong electrical waste substances, are incorporated into the cured resin, which significantly impairs the electrical insulation properties of the cured resin. However, since the anion component of the benzoate compound is a lipophilic benzoate ion, it has good compatibility with the epoxy resin, and since it is a weak electrolyte ion, the electrical insulation properties of the cured resin are not impaired.

In addition, since this compound is a salt of a phosphonium cation, which is a strong basic group, and a benzoate anion, which is a weakly acidic group, it has stronger activity as an epoxy resin curing agent than quaternary phosphonium halides, which are neutral salts, and has a shorter pot life. It has the characteristic that the heat curing property does not deteriorate even if it is significantly extended. The present invention is applicable to cases in which quaternary phosphonium benzoate ft and compound 46ff are used alone as a curing agent, and other curing agent components 1 such as aliphatic polyabane and aromatic polyamine.

Amine salts, dicyandiamide, urea, melamine.

It also includes combinations with imidazole compounds, polycarboxylic acid anhydrides, polyhydric phenols, hydrazide compounds, and the like.

The polyepoxy compound in the present invention has an average of 1 per molecule.
The polyepoxy compound may contain many individual epoxy groups, or may be interposed in the middle of the molecular formula, and the polyepoxy compound may be aliphatic, cycloaliphatic, aromatic or heterocyclic, and a hydroxyl group.

Alkyl group, alkoxy group, ester group, acetal group,
It may also be substituted with non-interfering substituents such as ether groups.

The most desirable polyepoxy compounds are bisphenol A,
Bisphenol F, resorcinol, hydroquinone, 4.
4'-diphenol, dihydroxydiphenylsulfone, phenol/formaldehyde resin, cresol/
It is a polyglycidyl ether of polyhydric phenol such as formaldehyde resin. Examples of other suitable polyepoxy compounds include glycidyl ethers of polyhydric alcohols such as ethylene glycol, glopylene glycol, glycerin, trimethylolpropane, 1,4-butanediol, phthalic acid, tetrahydrophthalic acid,
These include polyglycidyl esters of polycarboxylic acids such as hexahydrophthalic acid, adipic acid, and dimer acid, glycidyl amines, epoxidized polyolefins, and epoxidized vegetable oils.

In addition, specific examples of the quaternary phosphonitam penzoate compound which is the most characteristic epoxy resin curing agent in the present invention include triethylbenzylphosphonium benzoate, n-butylphosphonium benzoate, Tetra-n-butylphosphonium p-methylbenzoate, Tetra-n-Butylphosphonium p-chlorobenzoate, Tetra-n-butylphosphonium rhochlorbenshade, Tetra-n-butylphosphonium p-tert, Butylbenzoate, Tri-n -butylmethylphosphonium p-hydroxybenzony),)! J-n-butylallylphosphonium p-
Abanobenzoate, tri-n-butylhexadecylphosphonium p-nitrobenzoate, tri-n-octylethylphosphonium 2,4--)chlorobenzony)
, )! I-n-oIf ethylphosphonium 3
-4-Dicarboxybenzoate.

Tris-2-cyanoethylallylphosphonium 2-nitro-4-chlorobenshade, tetraphenylphosphonium benzoate, tetraphenylphosphonium p-chlorobenshade, tetraphenylphosphonium m-chlorobenshade, ethyltriphenylphosphonium O
-hydroxybenzoate, ethyltriphenylphosphonium O-carboxybenzoate, ethyltriphenylphosphonium-p-cyanobenzoate, and tetrahydroxymethylphosphonium benzoate.

Note that the curable composition of the present invention contains dibutyl phthalate,
Plasticizers such as dioctyl phthalate, inert organic solvents or so-called reactive diluents.

In particular, monoepoxides such as butyl glycidyl ether, phenyl glycidyl ether, etc. may be included.

In addition, the composition obtained according to the present invention may contain extenders, fillers, reinforcing agents, etc. at any stage before curing.
sO additives 1 For example, pigments, dyes, flame retardants, thixotropic agents, flow inhibitors, polymeric substances as flexibility agents, etc. may be included.

Hereinafter, embodiments of the present invention will be described by way of examples.

Example 1 Polyepoxy compound (DIR-33 manufactured by Dow Chemical Company)
1) 5 parts by weight of the curing agent of the present invention were added to 100 parts by weight, and mixed and dissolved at room temperature.

This was heated at 780''C for 2 hours, and then at 130℃ for 4 hours.The resulting cured product was measured for heat distortion temperature, tensile strength, and volume resistivity.The results are shown in Table 1. For comparison, Table 1 also shows the physical properties of a friend-cured product obtained by curing in the same manner as above using tetra-n-butylphosphonium bromide instead of the curing agent of the present invention.

Example 2 Polyepoxy compound (DER-33 manufactured by Dow Chemical Company)
1) Prepare a homogeneous mixture of 100 parts by weight and 10 parts by weight of curing agent. Gelation time in 1201: of this composition,
Table 2 shows the results of pot life measurements at 40°C and the pot life-gelling time ratios determined therefrom.

The gelation time in the table above refers to the composition of 0.5 gr f placed on a hot plate maintained at 120 ± 0.5°C, metal,
・Stretch the composition t-2 to 3- with your arm and knead it while pressing it evenly at an interval of about 2 seconds. When you lift the spatula, no strings will be drawn between the composition and the spatula until - It says time. 1.Bottle life is the initial viscosity value when the composition is stored at a temperature of t-40°C and the viscosity change is measured.
This is the time it takes to double. Moreover, the pot life-gelling time ratio is the ratio of the gelling time to the pot life value.

Example 3 Polyepoxy compound (DER-33 manufactured by Dow Chemical Company)
100 parts by weight of 1), 10 parts by weight of dicyandiamide, tetra-n-butylphosphonium p-chlorobenzony)
A homogeneous mixture consisting of 1 part by weight of colloidal silica and 3 parts by weight of colloidal silica was heated at 150°C for 30 minutes, and the resulting cured product had a heat distortion temperature of 153°C.

The tensile shear strength was 195 kg/-.

Example 4 Polyepoxy compound (DER-33 manufactured by Dow Kebakar)
100 parts by weight of 1) and anhydrous hexahydrophthalene J180
parts by weight, and 0.5 parts by weight of tetraphenylphosphonium p-hydroxybenzoate at 80°C.
The cured product obtained by heating at 130°C for 2 hours and 3 hours has a heat distortion temperature of 132°C.

; 1 tension strength 498 edge/-1 bending strength 775Kp/m,
The compression strength was 102XKf/-.

Claims (1)

[Claims] 1. General formula ▲ Numerical formulas, chemical formulas, tables, etc. and R_5 and R_6 represent a hydrogen atom, a halogen atom, an alkyl group, an amino group, a nitro group, a carboxyl group, a hydroxyl group, or a cyano group. agent.