JP3289972B2 - Manufacturing method of epoxy resin adhesive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a novel epoxy resin adhesive, and more particularly, to a method for producing an epoxy resin adhesive having excellent adhesion to metals, particularly excellent impact strength and peel strength. is there.

[0002]

2. Description of the Related Art Conventionally, epoxy resin cured products have been widely used for paints, civil engineering, adhesives, electric / electronic materials and composite materials because of their excellent mechanical properties, electrical properties, chemical properties and thermal properties. It is used in the direction. However, the epoxy resin cured product has a major drawback of low impact strength. Among the epoxy resin adhesives currently on the market, the impact strength is improved and the impact strength is 10 kg.
-Some adhesives are as excellent as cm / cm2 or more, but even with this adhesive, the peel strength is 10 kg / 25mm or less, which is still insufficient as a structural adhesive.

Under such circumstances, in order to improve the impact strength and peel strength of the epoxy resin adhesive, for example, Japanese Patent Publication No. 57-30133 discloses an epoxy resin, an acrylonitrile-butadiene copolymer having a carboxyl group, And an epoxy resin composition comprising an imidazole compound. However, although the adhesive made of this epoxy resin composition has improved impact strength and peel strength, it is still insufficient as a structural adhesive.

Japanese Patent Application Laid-Open No. 58-91755 discloses that an incompatible liquid rubber is dispersed in an epoxy resin into fine particles, which are vulcanized with a vulcanizing agent to a particle size of 0.5 to 0.5. 30
A method for producing a μm vulcanized rubber-dispersed epoxy resin has been proposed. However, in this case, it is extremely difficult to control the particle size of the rubber-like fine particles in terms of reproducibility, and the distribution range of the particle size is extremely wide.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks, and an object of the present invention is to provide a method for producing an epoxy resin adhesive having excellent adhesion to metals, particularly excellent impact strength and peel strength. The purpose is to provide.

[0006]

According to the present invention, an equivalent ratio of epoxy group: anhydride group: amino group is from 100: 0.2 to 100: 0.2.
15: 0.2 to 15 , epoxy resin (A), polybasic acid anhydride (B), metal salt of aminocarboxylic acid having a primary and / or secondary amino group (C ′)
Is partially dissolved in a solvent, and the solvent is distilled off.
A method for producing an epoxy resin adhesive is provided.

Namely, the present inventors have found, after intensive studies to solve the above problems, the above-mentioned compounding ratio of the epoxy resin, a polybasic acid anhydride, an aminocarboxylic having a primary and / or secondary amino groups An epoxy resin adhesive obtained from a metal salt of an acid and a curing accelerator has excellent adhesiveness to metal, and it has been found that not only tensile shear strength but also impact strength and peel strength are remarkably improved. Things.

The epoxy resin (A) used in the present invention is not particularly limited in molecular structure, molecular weight and the like as long as it is a compound having two or more epoxy groups in a molecule. For example, bisphenol A type epoxy resin, bisphenol F type Epoxy resin, dimer acid glycidyl ester type epoxy resin, polyalkylene ether type epoxy resin, phenol novolac type epoxy resin, alicyclic epoxy resin, heterocyclic epoxy resin, diglycidyl epoxy resin, brominated epoxy resin, etc. are commonly used. Epoxy resin is used.

The polybasic acid anhydride (B) includes maleic anhydride, phthalic anhydride, succinic anhydride, dodecenyl succinic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrohydrogen. Phthalic anhydride, methylhymic anhydride,
Hetatic anhydride, tetrabromophthalic anhydride and the like.

[0010]

[0011] and an ionic bond with primary and / or secondary metal salts of aminocarboxylic acids containing amino groups (C ')
Te is, for example, amino acid, amino chlorobenzoic acid, aminomethyl benzoic acid, glycine, aminocaproic acid, caprylic acid, aminoundecanoic acid, and metal salts such as amino valeric acid. As the metal, an alkali metal such as lithium, sodium and potassium, an alkaline earth metal such as magnesium and calcium, and a transition metal such as zinc, nickel, aluminum, chromium and iron are used.

An epoxy group in the epoxy resin (A),
The charging ratio of the anhydride group in the polybasic acid anhydride (B) and the amino group in the metal salt of the aminocarboxylic acid ( C ′ ) is 0.2 to 0.2 for the epoxy group per 100 epoxy groups.
It is preferable that the number of amino groups is 15 and the number of amino groups is 0.2 to 15, and the proportion of the acid groups to the amino groups is 0.6 to 1.5 amino groups per one acid anhydride group.

When the amounts of the polybasic acid anhydride (B) and the metal salt of aminocarboxylic acid ( C ' ) to the epoxy resin (A) are smaller than the above, the effect of adding these compounds has almost no effect, and the amount is larger than this. In such a case, the obtained adhesive becomes a solid at room temperature, and the workability is undesirably reduced.

[0014]

[0015] The solvent used in the present invention, the epoxy resin (A), the polybasic acid anhydride (B), and aminocarboxy
Any one may be used as long as it can dissolve the mixture of the metal salt of the acid (C ′) . For example, N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone, dimethylsulfoxide, tetrahydrofuran, acetonitrile And the like, and these can be used alone or as a mixture.

Furthermore, the epoxy resin adhesive of the present invention may contain additives used in ordinary epoxy resin adhesives, such as plasticizers, fillers, coloring agents, reinforcing agents, and other modifiers having various purposes. May be blended.

The epoxy resin adhesive of the present invention comprises, for example, an epoxy resin (A), a polybasic anhydride (B),
RT metal salts of amino acids (C '), or is obtained by mixing the reaction under heating, the epoxy resin (A), the polybasic acid anhydride (B), and aminocapronitrile
If carboxylic acid metal salt (C ') does not dissolve the epoxy resin (A), the polybasic acid anhydride (B), aminocarboxylic
It is preferable that the acid metal salt ( C ′ ) is mixed in a solvent and partially reacted so that insolubles do not precipitate even when the solvent is removed. The reaction conditions in this case are preferably at 50 to 160 ° C. for about 30 minutes to 8 hours. After the reaction, the solvent is distilled off to obtain the epoxy resin adhesive of the present invention.

[0018]

[Action] Epoxy resin (A), polybasic acid anhydride (B),
The epoxy resin adhesive of the present invention obtained by reacting a metal salt of an aminocarboxylic acid and a metal salt of an aminocarboxylic acid (C ′) has excellent adhesion to metals, particularly excellent impact strength and peel strength. By mixing an appropriate amount of a polybasic acid anhydride and a metal salt of an aminocarboxylic acid into an agent, an amide bond is generated, and the internal cohesion due to hydrogen bonding between the amide bonds in the adhesive is increased. It is considered that the interaction between the amide bond and the metal surface is increased, so that the adhesion to the metal is increased, and in particular, the impact strength and the peel strength are increased.

Further, a metal salt of aminocarboxylic acid (C ')
Bonds with the catalyst for the etherification of epoxy groups.
Therefore, the curing of the epoxy resin is remarkably accelerated, and the heat resistance is also improved by the action of metal ions.

[0020]

Next, the present invention will be described in detail with reference to examples. Parts in Examples are parts by weight. The components used below are as follows. Epoxy resin a: Epomic R-139 (manufactured by Mitsui Petrochemical Industries, Inc., bisphenol-type epoxy resin having an epoxy equivalent of 183) Epoxy resin b: Epicoat 191 (manufactured by Shell Chemical Co., Ltd.)
Bisphenol-type epoxy resin having an epoxy equivalent of 162) polybasic anhydride a: hexahydrophthalic anhydride polybasic anhydride b: methylhymic anhydride amino compound a: 4,4′-diaminodiphenylmethane amino compound b: p-amino Magnesium salt of benzoic acid Amino compound c: Calcium salt of p-aminobenzoic acid Amino compound d: Hexamethylenediamine Amino compound e: N-methylaniline Amino compound f: 3,3'-diaminodiphenyl sulfone Curing accelerator a: N , N-benzyldimethylamine curing agent a: Tomide # 296 (Fuji Kasei Kogyo; polyaminoamide curing agent)

The glass transition temperature is obtained by measuring the cured product of the adhesive by using a torsional free damping type viscoelasticity measuring device (manufactured by Resca) at a frequency of 0.1 to 3.0 Hz and a heating rate of 2 ° C./min. Determined based on The heat distortion temperature of the cured product of the adhesive was measured in accordance with ASTM D648-82.

Adhesion Test After applying an epoxy resin adhesive to the test piece and superimposing,
Post-curing was performed at 150 ° C. overnight and further at 180 ° C. for 4 hours. <Tensile shear strength> Using a cold-rolled steel plate as a test piece,
Measured according to ASTM D1002-64. <Impact strength> Using a rolled steel material for general structure as a test piece,
Measured according to ASTM D950-54. <Peeling strength> Using a cold-rolled steel plate as a test piece,
Measured according to 4578.

Embodiment 1(Reference example)  100 parts of epoxy resin a, polybasic acid anhydride a1.08
After mixing 0.69 part of the amino compound a
Stirred at 10 ° C for 10 minutes to make uniform. 80 ° C
After cooling, add 1.0 part of curing accelerator a, mix,
A thick inventive epoxy resin adhesive was obtained. Made of this adhesive
Preparation charge of epoxy group, acid anhydride group and amino group during production
In this case, the acid anhydride group is 1.25 per 100 epoxy groups.
And 1.25 amino groups. This epoxy resin bonding
Adhesion was performed using an adhesive. As a result,
Tensile shear strength is 210 kg / cm2, impact strength is 13.9 kg
Cm / cm2, peel strength was 18.3 kg / 25 mm.

Comparative Example 1 85.6 parts of polybasic acid anhydride a and amino compound a
After melting 5.6 parts at 130 ° C., the mixture was cooled to 80 ° C., and 100 parts of epoxy resin a and a curing accelerator a0.2
Parts were added and mixed to obtain a viscous epoxy resin adhesive.
The preparation ratio of the epoxy group, the acid anhydride group, and the amino group at the time of production of the adhesive was 100 epoxy groups, 100 acid anhydride groups, and 10 amino groups. Bonding was performed using this epoxy resin adhesive, and an adhesion test was performed. As a result, the tensile shear strength was 131 kg / cm2 and the impact strength was 2.8.
kg · cm / cm 2, and the peel strength was 1.3 kg / 25 mm.

Example 1 As shown in (Reference Example), when the epoxy resin adhesive of the present invention is used for bonding a metal, the impact strength and peel strength, which are disadvantages of the conventional epoxy resin adhesive, are greatly improved. . On the other hand, the conventional epoxy resin adhesive shown in Comparative Example 1 has a very low impact strength and peel strength because of a large amount of the polybasic anhydride, and could not be used as a structural adhesive at all. .

Examples 2 and 3 Polybasic acid anhydrides and aminocarboxylic acids having the formulations shown in Table 1 were prepared.
After dissolving the metal salt and the epoxy resin in N, N-dimethylformamide and reacting at 130 ° C. for 2 hours, the N, N-dimethylformamide is distilled off under reduced pressure to obtain a viscous epoxy resin adhesive of the present invention. I got Table 1 shows properties of the epoxy resin adhesive.

Embodiment 4(Reference example)  The polybasic acid anhydride, amino compound, and
And epoxy resin dissolved in N, N-dimethylformamide
After reacting at 130 ° C for 3 hours, the N, N
Methylformamide was distilled off. Cool the mixture to 80 ° C.
After cooling, 1.0 part of curing accelerator a was added and mixed,
Epoxy resin adhesive was obtained. This epoxy resin adhesive
Are shown in Table 1.

Comparative Example 2 To 100 parts of an epoxy resin a, 2 parts of a curing accelerator a were added.
An epoxy resin adhesive was obtained. Table 1 shows properties of the epoxy resin adhesive.

[0029]

[Table 1] Numbers in parentheses indicate epoxy groups 10 in the charge composition.
Number of anhydride groups and amino groups per 0 groups.

Examples 5 to 6(Reference example)  Polybasic acid anhydride, amino compound, and
And epoxy resin dissolved in N, N-dimethylformamide
After reacting at 130 ° C for 3 hours, the N, N-di
Methylformamide was distilled off. Cool the mixture to 80 ° C.
After cooling, 1.0 part of curing accelerator a was added and mixed,
Epoxy resin adhesive was obtained. This epoxy resin adhesive
Are shown in Table 2.

Comparative Example 3 A curing accelerator b was added to 42.9 parts by weight of 100 parts by weight of an epoxy resin a.
Parts by weight were mixed to obtain an epoxy resin adhesive. Table 2 shows properties of the epoxy resin adhesive.

[0032]

[Table 2] Numbers in parentheses indicate epoxy groups 10 in the charge composition.
Number of anhydride groups and amino groups per 0 groups.

[0033]

As described above, the epoxy resin adhesive of the present invention has excellent adhesion to metal, and not only tensile strength, but also the impact strength and peel strength, which are disadvantages of the epoxy resin adhesive, are extremely large. It is expected that the use as a structural adhesive will further expand. Furthermore, the fact that by using the amino compound having ion bonds as an amino compound, since ionic bonds to accelerate the curing of the epoxy resin, without necessarily requiring a curing accelerator, also to improve the heat resistance by the action of metal ions The effect is seen. Therefore, the epoxy resin adhesive of the present invention,
It is extremely useful in practice.

Claims (1)

(57) [Claims] 1. A epoxy group: anhydride groups: 100 amino group equivalent ratio: 0.2 to 15: 0.2 to 15 and so as
The epoxy resin (A), the polybasic acid anhydride (B), amino acids having a primary and / or secondary amino groups
Metal salt (C ′) is dissolved in a solvent and partially reacted.
And then distilling off the solvent .