JP3436558B2 - Epoxy resin composition - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel epoxy resin composition, more specifically, physical properties of the obtained cured product,
In particular, the present invention relates to an epoxy resin composition which has significantly improved impact resistance and, when used as an adhesive, has excellent adhesiveness to metals, particularly impact peel strength and peel strength.

[0002]

2. Description of the Related Art Conventionally, cured epoxy resins have been widely used in paints, civil engineering, adhesives, electric / electronic materials and composite materials due to their excellent mechanical properties, electrical properties, chemical properties and thermal properties. It is used in the direction. As a method for curing an epoxy resin, a method using a compound that undergoes an addition reaction with an epoxy group, such as an amine-based curing agent, an acid anhydride-based curing agent, a polyamide-based curing agent, a phenol resin-based curing agent, and a tertiary amine, imidazole There is known a method of using a catalyst for polymerizing an epoxy group such as a group of Lewis acids.

However, the epoxy resin cured product cured by these methods has a major drawback of low impact strength.

Also, the epoxy resin adhesives currently on the market generally have the drawback of low impact peel strength and low peel strength, although they are generally excellent in tensile shear strength. Some of these have improved impact strength, and some have excellent impact peel strength of 10 kg · cm / cm ² or more, but even in this case, the peel strength is 10 kg / 25 mm or less. It was insufficient as an adhesive for use.

Under these circumstances, various attempts have been made to improve the impact strength of the cured epoxy resin product. In these methods, vulcanized rubber particles, rubber components such as liquid rubber, or low-molecular-weight polyurethane, thermoplastic resin such as polycarbonate are mixed in the epoxy resin,
It is intended to improve impact resistance by imparting flexibility to a cured epoxy resin product. For example, Japanese Examined Patent Publication No. 57-30133 discloses an epoxy resin composition comprising an epoxy resin, an acrylonitrile-butadiene copolymer having a carboxyl group, and an imidazole compound, and a cured product obtained from this epoxy resin composition. The article has improved impact strength, and when iron is bonded, impact peel strength and peel strength are improved. However, it was still insufficient as a structural adhesive. Further, in JP-A-58-91755, an incompatible liquid rubber is dispersed in an epoxy resin in the form of fine particles, which is vulcanized with a vulcanizing agent to give a vulcanizate having a particle size of 0.5 to 30 μm. A method for producing a vulcanized rubber-dispersed epoxy resin has been proposed. However, in this case, it was extremely difficult to control the particle size of the rubber-like fine particles in terms of reproducibility, and the particle size distribution range was extremely wide.

On the other hand, Japanese Examined Patent Publication No. 52-6747 and Japanese Examined Patent Publication No. 52-24933 disclose epoxy resin adhesive compositions containing a polyamide and having excellent peel strength. However, the polyamides used for these are those synthesized by a condensation reaction of a specific dibasic acid or its lower alkyl ester and a polyalkylene polyamine, and those having a high molecular weight, which has a large effect of addition, are preferable. After reacting for a time, it was necessary to further remove unreacted polyalkylene polyamine. Further, such a polyamide could not be expected to have a sufficient effect unless it was added in a large amount to the epoxy resin.

As a curing agent for an epoxy resin, a polyamide obtained by reacting a dimer acid with a polyamine is commercially available. Even if an epoxy resin is cured with this polyamide, the impact strength of the cured product is almost the same. It did not rise, and even when it was used as an adhesive for metals, the impact peel strength and the peel strength were hardly improved.

[0008]

The present invention has been made in view of the above-mentioned drawbacks, and an object thereof is to provide a cured product having excellent physical properties, particularly impact strength, and further to be used as an adhesive. Aims to provide an epoxy resin composition having excellent adhesiveness to metals, particularly impact peel strength and peel strength.

[0009]

According to the present invention , a polybasic acid anhydride and an amino compound having a primary and / or secondary amino group are added to 100 parts by weight of an epoxy resin (A).
Of non-hydroxyl groups in polybasic acid anhydrides and amino acid compounds in amino compounds.
0.2 to 30 parts by weight of an adduct (B) having an amide group and a carboxyl group in one molecule, which is an equivalent reaction product of a mino group.
Epoxy resin composition characterized by blending is provided a further, relative to the epoxy resin (A) 100 parts by weight of
Selected from tertiary amines, imidazoles, and Lewis acids
Characterized in that 0.01 to 7 parts by weight of the catalyst is added.
The above epoxy resin composition is provided.

That is, the inventors of the present invention have conducted extensive studies to solve the above-mentioned problems, and as a result, have found that the epoxy resin (A) contains a polybasic acid anhydride and an amino compound having a primary and / or secondary amino group . , Non-hydroxyl groups and amino acids in polybasic acid anhydrides
Addition product (B) having an amide bond and a carboxyl group in one molecule, which is obtained by reacting with an amino group in a compound in an equivalent amount
When a small amount (hereinafter referred to as an additive (B)) is blended, not only the impact resistance of the cured product is significantly improved, but also when a metal is used as an adhesive agent, not only the tensile shear strength but also the impact The inventors have found that the peel strength and the peel strength are remarkably excellent, and have reached the present invention.

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

Examples of the polybasic acid anhydride used for producing the adduct (B) include maleic anhydride, phthalic anhydride, succinic anhydride, dodecenyl succinic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride and hexahydro. Phthalic anhydride, methylhexahydrophthalic anhydride,
Examples thereof include methyl hymic acid anhydride, methyl nadic acid anhydride, het anhydride, and tetrabromophthalic anhydride.

On the other hand, the amino compound may be any amino compound having at least one primary and / or secondary amino group per molecule, and examples thereof include aniline and N-.
Methylaniline, N-ethylaniline, toluidine, phenylenediamine, diaminodiphenylsulfone, diaminodiphenylmethane, diaminodiphenyl ether,
Tolylenediamine, triaminobenzene, ethylamine, propylamine, butylamine, hexylamine,
Benzylamine, ethylenediamine, tetramethylenediamine, hexamethylenediamine, etc. are used.

The adduct (B) used in the present invention is, for example,
It can be obtained by reacting the above-mentioned polybasic acid anhydride with an amino compound having a primary and / or secondary amino group in the presence or absence of a solvent. Further, this reaction can be carried out under heating, but it is preferable that the reaction proceeds sufficiently even at room temperature and, if the heat generation is large, it is cooled if necessary. The adduct (B) thus obtained has both an amide bond and a carboxyl group in one molecule.

The charging ratio of the polybasic acid anhydride and the amino compound having a primary and / or secondary amino group at the time of production is such that the hydroxyl group-free in the polybasic acid anhydride and the amino compound in the amino compound are mixed.
It is necessary to make the mino group equivalent . According to
In the present invention, the unreacted polybasic acid in the reaction product is
Amine having an anhydride or a primary and / or secondary amino group
The compound has the advantage that the compound does not easily remain .

Additive (B) to epoxy resin (A)
The amount used is 0.2 per 100 parts by weight of the epoxy resin.
-30 parts by weight is preferred.

Addition product (B) to epoxy resin (A)
If the amount used is less than this, the effect of adding these is almost non-existent, and if the amount used is large, the peel strength decreases again, which is not preferable.

The epoxy resin composition of the present invention can be sufficiently cured only by the epoxy resin (A) and the adduct (B), but epoxy resins such as tertiary amines, imidazoles, Lewis acids and the like. It is preferable to use a catalyst usually used in the composition because the curing rate is increased. The addition amount is 0.0 with respect to 100 parts by weight of the epoxy resin (A).
1 to 7.0 parts by weight is preferable.

Further, the epoxy resin composition of the present invention includes additives used in ordinary epoxy resin compositions such as plasticizers, fillers, colorants, reinforcing agents, and other modifiers having various purposes. There is no problem in blending.

The epoxy resin composition of the present invention can be easily obtained by mixing the epoxy resin (A) and the adduct (B) at room temperature or under heating.

[0021]

The epoxy resin (A) is treated with an adduct (B) having an amide bond and a carboxyl group in one molecule, which is obtained by reacting a polybasic acid anhydride with an amino compound having a primary and / or secondary amino group. The added epoxy resin composition of the present invention not only significantly reduces the impact resistance of the obtained cured product, in spite of the small amount of the additive (B) added, but also improves the adhesiveness to metal, particularly, Excellent impact peel strength and peel strength.

Although the reason for exhibiting such excellent performance is not clear, the carboxyl group in the adduct (B) mixed in a small amount with the epoxy resin reacts with the epoxy group in the epoxy resin to form the adduct (B). Is bonded to the epoxy resin via a covalent bond, and the amide bond resulting from the adduct (B) increases the interaction between the epoxy resin and the metal surface, thereby increasing the adhesiveness with the metal, and particularly impact debonding. It is considered that the strength and peel strength are increased.

[0023]

EXAMPLES Next, the present invention will be described in detail with reference to Examples. Parts in the examples indicate parts by weight.

The ingredients used in the following are as follows.

Epoxy resin a: Epomic R-139
(Mitsui Petrochemical Co., Ltd., bisphenol type epoxy resin with an epoxy equivalent of 183) Epoxy resin b: Epicoat 191 (Shell Chemical Co.,
Epoxy Epoxy Resin Epoxy Equivalent 162) Polybasic Anhydride a: Hexahydrophthalic Anhydride Polybasic Anhydride b: Succinic Anhydride Polybasic Anhydride c: Anhydromethylnadic Acid Amino Compound a: Aniline Amino Compound b: 4,4'-diaminodiphenylmethanamino compound c: N-monomethylaniline amino compound d: hexamethylenediamine catalyst: N, N-dimethylbenzylamine curing agent: Tomeide # 296 (manufactured by Fuji Kasei Kogyo; polyamide-based curing agent) adduct The acid value of (B) is 0.
It was determined by titration with a 1N KOH aqueous solution.

The flexural strength, tensile strength, and impact strength of the cured product are ASTM D790-81 and ASTM D790-81, respectively.
D638-82 and ASTM D256-81, respectively.

Adhesion test After coating and overlaying the epoxy resin composition on the test piece,
It was heat-cured at 150 ° C. for 24 hours.

Tensile shear strength-measured according to ASTM D1002-64 using cold rolled steel sheet as the test piece.

Impact Peel Strength-Rolled steel for general structure was used as a test piece and measured according to ASTM D950-54.

Peel strength-measured according to ISO 4578 using cold rolled steel sheets as test pieces.

Production Example 1 62.3 g of polybasic acid anhydride a dissolved in chloroform
To (0.40 mol), 37.7 g (0.40 mmol) of amino compound a dissolved in chloroform was gradually added while cooling, and the mixture was reacted at room temperature for 1 hour. After the reaction, chloroform was concentrated under reduced pressure to obtain a white powder. By recrystallizing this white powder with methanol, an adduct a of the polybasic acid anhydride and the amino compound used in the present invention was obtained. Table 1 shows the acid value and elemental analysis value of the obtained adduct a. From this result, it was confirmed that the product was the adduct a represented by Chemical formula 1.

[0032]

[Chemical 1]

Production Example 2 In 49.7 g (0.25 mol) of amino compound b dissolved in a mixed solvent of chloroform-dimethylformamide,
Polybasic acid anhydride b5 dissolved in dimethylformamide
0.3 g (0.50 mol) was gradually added while cooling, and a white precipitate was deposited by reacting at room temperature for 1 hour. This was filtered and washed with chloroform to obtain an adduct b of the polybasic acid anhydride and the amino compound used in the present invention. Table 1 shows the acid value and the elemental analysis value of the obtained adduct b. From this result, it was confirmed that the product was the target adduct b.

Production Example 3 Used in the present invention by mixing 62.4 g (0.35 mol) of polybasic acid anhydride c and 37.6 g (0.35 mol) of amino compound c and reacting at 80 ° C. for 30 minutes. Adduct c of polybasic acid anhydride and amino compound c
Got Table 1 shows the acid value and the elemental analysis value of the obtained adduct c. From this result, it was confirmed that the product was the target adduct c.

Production Example 4 72.6 g of polybasic acid anhydride a dissolved in chloroform
To (0.47 mol), 27.4 g (0.236 mol) of amino compound d dissolved in chloroform was gradually added while cooling, and the mixture was allowed to react at room temperature for 2 hours, whereby a white precipitate was deposited. This was filtered and washed with chloroform to obtain an adduct d of the polybasic acid anhydride and the amino compound used in the present invention. Table 1 shows the acid value and elemental analysis value of the obtained adduct d. From this result, it was confirmed that the product was the target adduct d.

[0036]

[Table 1]

Examples 1 and 2 100 parts of the epoxy resin a and the adduct a obtained in Production Example 1 were dissolved by stirring at 120 ° C. until homogeneous, then cooled to room temperature, and a catalyst was added to the present invention. The epoxy resin composition of was obtained. This composition was subjected to 16 at 130 ° C.
A cured product was obtained by curing at 180 ° C. for 4 hours. Table 2 shows the flexural strength, tensile strength, and impact strength of this cured product. Further, a rolled steel plate or a rolled steel material was bonded using this composition, and an adhesion test was conducted. The results are also shown in Table 2.

Comparative Example 1 An epoxy resin composition was obtained by adding 2 parts of catalyst to 100 parts of epoxy resin a. This composition at 130 ° C. for 16 hours,
A cured product was obtained by further curing at 180 ° C. for 4 hours. Table 2 shows the flexural strength, tensile strength, and impact strength of this cured product. Further, the results of an adhesion test using this composition are also shown in Table 2.

[0039]

[Table 2]

As shown in the examples, the cured product obtained by curing the epoxy resin composition of the present invention containing the adduct (B) of the polybasic acid anhydride and the amino compound has flexural strength and The impact resistance is significantly improved without lowering the tensile strength, and shows significantly superior physical properties to the cured products of Comparative Examples. Furthermore, when a metal is adhered using the epoxy resin composition of the present invention, impact peel strength and peel strength, which are the drawbacks of conventional epoxy resin adhesives, are significantly improved. On the other hand, the conventional epoxy resin compositions shown in Comparative Examples do not contain an adduct of a polybasic acid anhydride and an amino compound, so that the impact peel strength and the peel strength are extremely low, and they are used as structural adhesives. Was completely unusable.

Examples 3 to 7 Epoxy resin and a predetermined amount of adduct were dissolved by stirring at 120 ° C. until homogeneous, then cooled to room temperature, and a catalyst was added to obtain an epoxy resin composition of the present invention. It was A rolled steel plate or rolled steel material was bonded using this composition, and an adhesion test was conducted. The results are shown in Table 3.

Comparative Example 2 An epoxy resin composition was obtained by mixing 100 parts by weight of the epoxy resin a with 42.9 parts by weight of a polyamide curing agent containing an amide bond. Table 3 also shows the results of an adhesion test using this epoxy resin composition.

[0043]

[Table 3]

[0044]

As described above, when the epoxy resin composition of the present invention is used as a cured product, the epoxy resin composition has excellent flexural strength and tensile strength, but has a great drawback of the epoxy resin, that is, impact resistance. It has been greatly improved, and its application is expected to expand as a casting material and laminated material. Further, when used as an adhesive, the adhesive strength to metal is excellent, and not only the tensile shear strength but also the impact peel strength and peel strength, which are the drawbacks of the epoxy resin adhesive, are significantly increased. Is expected to expand further. Therefore, the epoxy resin composition of the present invention is extremely useful in practice.

Claims (2)

(57) [Claims] 1. To 100 parts by weight of epoxy resin (A)
Of a polybasic acid anhydride and an amino compound having a primary and / or secondary amino group in the polybasic acid anhydride
And 0.2 to 30 parts by weight of an adduct (B) having an amide group and a carboxyl group in one molecule which is a reaction product of an amino group in an amino compound . 2. Further, 100 parts by weight of the epoxy resin (A) is added.
In contrast, from tertiary amines, imidazoles, Lewis acids
The epoxy resin composition according to claim 1, wherein 0.01 to 7 parts by weight of the selected catalyst is added .