JPS61188413A - Epoxy resin composition - Google Patents

Abstract

PURPOSE:To obtain an epoxy resin composition improved in heat resistance, flexibility, etc., by using a polyepoxy resin obtained by reacting a mixture of a specified dieposy resin and a novolak epoxy resin with a bisphenol and a curing gent for epoxy resin as essential components of the resin composition. CONSTITUTION:A polyepoxy resin (A) and a curing agent (B) for epoxy resin are used as essential components. Component A is a polyepoxy resin of an epoxy equivalent of 200-2,000, obtained by reacting a mixture of a diepoxy resin (a-1) of an epoxy equivalent of 170-800, having a skeleton comprising at lest one selected from among bisphenol A, bisphenol F and tetrabromobisphenol A, and a novolak epoxy resin (a-2) having 2.3-10, on the average, glycidyl groups per molecule with at least one bisphenol (a-3) selected from among bisphenol A, bisphenol F and tetrabromobisphenol A. As component B, any usual curing agent such as an aliphatic or aromatic amine can be used.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a new and developed epoxy resin composition. A polyfunctional epoxy resin obtained by reacting such specific bisphenols with a mixture with a type epoxy resin is an essential base resin component, and on the other hand, a curing agent for epoxy resin is an essential curing agent component. The present invention relates to resin compositions which develop excellent cured product properties such as water resistance, mechanical strength and flexibility and are therefore suitable for lamination, mold casting, coatings or adhesives.

[Problems to be solved by the prior art and the invention] Bisphenol A type epoxy tree as the most general-purpose one,
Due to its fat-bifunctional nature, it may lack heat resistance depending on its use.

In such cases, for the purpose of improving heat resistance,
It is common to use a polyfunctional novolac type epoxy resin in combination.

In addition, in fields where high flammability is required, brominated epoxy resins containing tetrabromobisphenol A as a single bisphenol component, or brominated epoxy resins that are a cocondensation of tetrabromobisphenol A and bisphenol A, are commonly used. Novolak type epoxy resins are often used in combination when heat resistance is also required.

In addition, so-called bisphenol F type epoxy resins, in which part or all of the bisphenol human skeleton has a bisphenol F skeleton, are also used, although this is rare.

In any case, if a novolanc type epoxy resin is used in combination with a trifunctional epoxy resin using various bisphenols as mentioned above for the purpose of imparting heat resistance, this heat resistance -
Although the improvement is certain, on the other hand, the cured product tends to be hard and brittle, and its flexibility decreases, so it is recommended to increase the amount of novolac type epoxy resin, considering only heat resistance. has problems and is generally disadvantageous in terms of cost.

For example, in epoxy resin laminates, the so-called G-10 grade, which is not flame retardant, uses bisphenol A type solid epoxy resin as the main raw material, and phenol novolac type or talesol novolac type epoxy resin is added to provide heat resistance. A mixture of both of these components is often used.

On the other hand, the flame-retardant FR-4 grade is a low-bromine type with a bromine content of at most 20 to 30% by weight, which is based on bisphenol A liquid epoxy resin and modified with tetrabromobisphenol A. Epoxy resins are used as the main raw material, and phenol novolac type epoxy resins, talesol novolac type epoxy resins, etc. are mixed with this for the purpose of imparting heat resistance.

However, when such laminates are used, the combined use of novolac-type epoxy resins deteriorates the dimensional stability of the laminates, makes them hard and brittle, and reduces drill resistance. The reality is that similar problems arise in the fields of powder coatings and molding materials, where similar resins are used in combination.

[Means for solving problems]

However, in view of the various drawbacks of the prior art as described above, the present inventors have developed a new technology that is not only heat resistant but also
As a result of intensive research in order to obtain an epoxy resin composition with well-balanced properties such as mechanical strength, water resistance, and flexibility, as mentioned above, we simply blended a novolak type epoxy resin with a trifunctional epoxy resin. Not only (
discovered that an extremely effective epoxy resin composition suitable for the above purpose could be obtained by preparing a structure in which these bifunctional epoxy resins and novolac type epoxy resin were grafted in advance. As a result, the present invention was completed.

That is, the present invention has, as an essential component, a skeleton based on at least one bisphenol selected from the group consisting of bisphenol A, bisphenol F, and tetrabromobisphenol A (hereinafter also referred to as a bisphenol skeleton), and an epoxy A trifunctional epoxy resin (a-1) having an equivalent weight of 170 to 800, and a trifunctional epoxy resin (a-1) having an equivalent weight of 170 to 800,
．． A mixture with a novolac type epoxy resin (a-2) having 3 to 10 glycidyl groups is mixed with a small amount (both one type of bisphenol) selected from the group consisting of bisphenol A, bisphenol F, and tetrabromobisphenol (a-3). ), the polyfunctional engineered 4i resin (A) has a myeboxyl equivalent of 200 to 2□000.
An object of the present invention is to provide an epoxy resin composition which is excellent in heat resistance, mechanical strength, water resistance, flexibility, etc., and comprises a curing agent (B) for epoxy resins.

Here, the trifunctional epoxy resin (a-1) used to prepare the multifunctional epoxy resin (A), which is the first essential component constituting the composition of the present invention, refers to 1 liter of bisphenol (a-3 ), using at least one compound selected from bisphenol A, bisphenol F and tetrabromobisphenol A, and epichlorohydrin.
Liquid or solid (brominated) epoxy resins having two glycidyl ethers in the same molecule, which can be easily obtained by the method described in ``Epoxy Resins'', or epoxy resins obtained in this way. As a base,
Further, at least one compound selected from bisphenol A, bisphenol F and tetrabromobisphenol A used as bisphenols (a-3) is added to a known compound as described in the above-mentioned "epoxy resin". Refers to a (brominated) epoxy resin having a structure as shown in the following general formula, which is obtained by reacting by the method of It is a conflict that collectively refers to.

For the mixture of the polyfunctional epoxy resin (A), the thus obtained trifunctional epoxy resin (a-1), and a novola 7-type epoxy resin (a-2) as described below. Since it is obtained by reacting bisphenol 11(a-3) to introduce a novolak structure into the molecule, if the amount of bisphenol (a-3) used is small, this bisphenol 11(a-3) ) is less effective.

For example, when the epoxy equivalent of the bifunctional epoxy resin (a-1) is high, that is, the molecular weight of the resin (a-1) is high, and you do not want the molecular weight of the target polyfunctional epoxy resin (A) to be too high. In the end, the amount of bisphenol 11(a-3) used, which also has the role of increasing the molecular weight, has to be suppressed, but as a result, the effect of grafting is diluted by that amount. It is inevitable that it will become.

Therefore, the molecular weight of the bifunctional epoxy resin (a-1) to be used is preferably lower, except in the case where a relatively high molecular weight polyfunctional epoxy resin (A) is to be obtained.

Next, the above-mentioned novolac type epoxy resin (a-2)
is based on a novolak obtained from a monophenolic compound such as phenol and/or alkylphenol and formaldehyde, or a novolak obtained from a diphenolic compound such as dihydroxybenzene such as resorcinol or bisphenol A and formaldehyde, Based on novolac-type epoxy resin or xylene resin obtained by reacting epichlorohydrin with such novolanc by a known method as described in "Epoxy resin" listed above, this is used as a base for phenol, substituted phenol or phenol. Among the epoxidized products of so-called modified phenolic resins, etc., which are obtained by modification with novolac and are described in "Plastics" Volume 33, No. 7 and No. 8 published by Kogyo Kenkyukai, etc. The average number of glycidyl groups is within the range of 2.3 to 10.

The above-mentioned epoxy resin (a) used in preparing the polyfunctional epoxy resin (A) is
-1), epoxy resin (a-2), and bisphenols (a-3), the usage ratio of each raw material component varies depending on the use and required performance of the composition of the present invention. If heat resistance must be emphasized, the ratio of novolac type epoxy resin (a-2) should be increased, and in addition, in order to increase the grafting rate to this resin (a-2). Also, bisphenol 1! [The usage amount of (a-3) also needs to be increased.

In addition, when obtaining the composition of the present invention for use in laminates, impregnating properties are important, so as mentioned above, it is not possible to increase the molecular weight of the polyfunctional epoxy resin (A) so much. The molecular weight of the epoxy resin (a-1) itself can also be determined. The amount of bisphenols (a-3) used should be raised to an appropriate level while keeping the amount low. It is necessary to keep this in mind.

Furthermore, when using it for applications such as powder coatings,
From the point of view of performance, it is difficult to use a material with too low a molecular weight or a low melting point, so the polyfunctional epoxy resin (
It is necessary to increase the molecular weight of A) to a certain extent,
In such cases, too low molecular weight epoxy resin (a
-1), the amount of bisphenol* (a-3) used will increase, and at the same time, the amount of epoxy resin (a-2) will increase.
), if the amount of polyfunctional epoxy resin (
The risk of gelation in A) also arises, so care must be taken.

Therefore, in such cases, bisphenols (a-3
), it becomes necessary to use an epoxide (a-1) having a higher molecular weight.

In any case, when designing to obtain the resin (A) having the desired molecular weight and desired heat resistance, special attention should be paid to the fact that the degree of grafting to the epoxy resin (a-2) is small. On the contrary, it is important to avoid exceeding the desired grafting range and reaching gelation, which requires sufficient preliminary experiments and Compared to the simple blending method, it is important to design while confirming the effect of grafting.

Thus, each of the aforementioned bifunctional epoxy resins (a
-1), to carry out the reaction using novolac type epoxy resin (a-2) and bisphenols (a-3),
The above-mentioned "epoxy resin" and even JP-A-48-83
The polyfunctional epoxy resin (A) having five purposes, which is excellent in heat resistance, mechanical strength, water resistance, flexibility, etc., can be obtained by a known method as described in Japanese Patent No. 199.

In the present invention, the use of the multifunctional epoxy resin (A) obtained as described above is a method of grafting this resin (a-2) in advance to the novolac type epoxy resin (a-2). The polyfunctional epoxy resin (A) of the present invention obtained by taking the above method and the conventional epoxy blend obtained by simply blending the resin (a-2) are different from each other. Even if the cured products of both resins are designed to have the same heat resistance, such as heat distortion temperature or glass transition point (Tg), the former method, that is, polyfunctional epoxy resin (A
), this novolac type epoxy resin (
The amount of a-2) used can be reduced compared to the latter method, that is, when an epoxy blend is used, and as a result, the former method has better toughness, Furthermore, the former case also has excellent water resistance, which is a surprising result, and can therefore be said to be truly advantageous.

Furthermore, when designing the amount of novolac type epoxy resin to be the same between the case of using the polyfunctional epoxy resin (A) in the present invention and the case of using a conventional simple blend, Results have been obtained that the cured product according to the present invention is superior in heat resistance, mechanical strength, water resistance, etc., and is also tougher.

On the other hand, as the curing agent (B) for epoxy resin, which is the second essential component constituting the composition of the present invention, any compound known and commonly used as a curing agent for epoxy resin can be used. Examples include aliphatic amines such as diethylenetriamine and triethylenetetramine; aromatic amines such as metaphenylenediamine, diaminodiphenylmethane, and diaminodiphenylsulfone;
Polyamide resins or modified products thereof; or acid anhydrides such as maleic anhydride, hexahydrophthalic anhydride, pyromellitic anhydride, dicyandiamide,
Imidazole, BF.

- Latent curing agents such as amine complexes or guanidine derivatives.

When using each of these compounds as a curing agent, it is often necessary to also use a curing accelerator, but in such cases, tertiary amines such as dimethylbenzylamine, imidazole, etc. It goes without saying that known and commonly used compounds including metal compounds of the same type or various types can be used.

In addition, the above-mentioned polyfunctional epoxy resin (A) in the present invention
The term polyfunctional shall mean a resin with an average functionality of greater than two.

Thus, the epoxy resin composition of the present invention contains both the above-mentioned essential components, the polyfunctional epoxy resin (A) and the curing agent for epoxy resin (B), in a solid content of 10% of the resin (A) component.
It is obtained by blending in a ratio of 2 to 70 parts by weight to 0 parts by weight. However, it should be noted that this blending ratio varies greatly depending on the type of curing agent (B) component used.

The composition of the present invention obtained in this manner may further contain various additives such as fillers and colorants, if necessary, and may also contain tar, pitch, amino resin, alkyd resin, phenol resin, etc. can also be used together.

〔Effect of the invention〕

The epoxy resin composition of the present invention not only has excellent heat resistance, mechanical strength, and water resistance, but also provides an extremely useful cured product that is strong and does not bend.

Because of these properties, the composition of the present invention is extremely useful and can be used in a wide range of applications such as laminated materials, molding materials, coating materials, and adhesives.

〔Example〕

Next, the present invention will be specifically explained with reference to Reference Examples, Examples, and Comparative Examples. In the following, all parts and percentages are based on 1F weight unless otherwise specified.

Reference Example 1 [Preparation example of polyfunctional epoxy resin (A)] 53 parts of liquid "Epiclon 850" (bisphenol A type epoxy resin manufactured by Dainippon Ink & Chemicals) with an epoxy equivalent of 190 and "Epiclon N- To a mixture consisting of 13 parts of 673J (cresol novolac type epoxy resin manufactured by the same company; epoxy equivalent lt -210, softening point -73°C), 34 parts of tetrabromobisphenol A was added, and the mixture was heated to 120°C and stirred. Further, 0.01 part of 2-methyl-imidazole was added and reacted at 150°C for 4 hours to obtain a solid target resin having an epoxy equivalent of 4□73 and a bromine content of 20%. Hereinafter, this will be abbreviated as resin (A-1).

Reference Example 2 (same as above) In place of Epiclon N-673J, the same amount of semi-solid Epiclon N-7404 (phenol novolac type epoxy resin manufactured by the same company; epoxy equivalent: -180) was used. A solid objective resin having an epoxy equivalent of 450 and a bromine content of 20% was obtained in the same manner as in J Reference Example 1 except for this.Hereinafter, this will be abbreviated as resin (A-2).

Reference example 3 (same as above) ' 52 parts of "Epicron 850" and "Epicron N-67"
A target resin having an epoxy equivalent of 831 and a melting point of 93° C. was obtained in the same manner as in Reference Example 1, except that 28 parts of bisphenol A was added to the mixture consisting of 20 parts of 34 and 20 parts of bisphenol A. Hereinafter, this will be abbreviated as resin (A-3).

Reference Example 4 (same as above) Liquid “Epicron 830J (bisphenol F type epoxy resin manufactured by the above company; epoxy equivalent: -175) 6
The epoxy resin was prepared in the same manner as in Reference Example 1, except that 20 parts of bisphenol F was added to the mixture consisting of 0 parts of epoxy resin and 20 parts of Epiclon N-673J.
0 and a melting point of 72° C. was obtained. Hereinafter, this will be abbreviated as resin (A-4).

Reference Example 5 (same as above) 65 parts of "Epiclon 152J (tetrabromo bisphenol A type epoxy resin manufactured by the same company; epoxy equivalent -360, melting point -60°C, bromine content = 47%)" and "Epiclon N-740J" The epoxy equivalent was 540 in the same manner as in Reference Example 1, except that 20 parts of tetrabromobisphenol A was added to the mixture consisting of 15 parts.
Thus, a desired resin having a melting point of 83° C. and a bromine content of 42% was obtained. Hereinafter, this will be abbreviated as resin (A-5).

Reference Example 6 [Preparation example of trifunctional epoxy resin (A') for comparison] A mixture of 46 parts of "Epiclone 850" and 34 parts of tetrabromobisphenol A was heated to 120°C, stirred, and further mixed with 2-methyl -0.01 part of imidazole was added and reacted for 4 hours at 150°C to obtain a solid control resin with an epoxy equivalent weight of 695 and a bromine content of 25%. Hereinafter, this will be abbreviated as resin (A'-1).

Reference Example 7 (same as above) The epoxy equivalent was 615 and the bromine content was the same as Reference Example 6, except that the amounts of "Epiclone 850" and tetrabromobisphenol A were changed to 52 parts and 35 parts, respectively. A control resin of 23% solids was obtained. Hereinafter, this will be abbreviated as resin (A'-2).

Reference example 8 (same as above) 60 parts of "Epicron 830" and 2 parts of bisphenol F
A mixture consisting of 0 parts was heated to 120°C, stirred, and 2 parts
- Add 0.01 part of methyl-imidazole and bring to 150°C.
A solid control resin having an epoxy equivalent weight of 570 and a melting point of 74° C. was obtained. Hereinafter, this will be abbreviated as resin (A'-3).

Reference Example 9 (same as above) A mixture of 68 parts of "Epiclone 152" and 17 parts of tetrabromobisphenol A was heated to 120°C and stirred, and further 0.01 part of 2-methyl-imidazole was added and the mixture was heated to 150°C. After 4 hours of reaction, the epoxy equivalent was 687.
A solid control resin with a melting point of 86° C. and a bromine content of 49% was obtained. Hereinafter, this will be abbreviated as resin (A'-4).

Examples 1 and 2 Each resin (A-1) obtained in Reference Examples 1 and 2
and (A-2) were each dissolved in methyl ethyl ketone, and then dissolved in methyl cellosolve in advance,
A mixed solution having a non-volatile content (NY) of 55% was prepared by adding the curing agent dicyandiamide and the curing accelerator dimethylbenzylamine in the amounts listed in Table 1. The amount of curing agent (B) at this time is polyfunctional epoxy resin (A).
The ratio was set to 0.25 mol per 1 epoxy group in the resin, and the amount of curing accelerator was set to 0.2 parts per 100 parts of solid content of the polyfunctional epoxy resin.

Thereafter, each mixed solution was used and cured under the following conditions to produce a laminate.

Next, each laminate was tested for physical properties of the cured product.
The results shown in the same table were obtained.

11 Provisional 1 Knotting Base Material: rWE-18 to -104-BZ2J (
Nittobo ■ glass cloth] Ply failure: 9 Resin content: about 40% Comparative Example 1 80 parts of the control resin (A'-1) obtained in Reference Example 6 and 20 parts of "Epicron N-673J" A mixture consisting of parts (
A laminate was produced in the same manner as in Examples 1 and 2, except that a mixed solution was used, and the physical properties of the cured product were evaluated in the same manner. The results are shown in Table 1.

Comparative Example 2 The same procedure as in Examples 1 and 2 was carried out except that 87 parts of the control resin (A'-2) obtained in Reference Example 7 and 13 parts of [Epicron N-673J] were used. A laminate was produced and the physical properties of the cured product were evaluated. The results are shown in Table 1.

Comparative Example 3 A laminate was produced in the same manner as in Comparative Example 1, except that the same amount of Epiclon N-740J was used instead of Epiclon N-673J, and the physical properties of the cured product were evaluated.

The results are summarized in Table 1.

Comparative Example 4 A laminate was produced in the same manner as Comparative Example 2, except that the same amount of Epiclon N-7404 was used instead of Epiclon N-673J, and the physical properties of the cured product were evaluated.

The results are summarized in Table 1.

Examples 3 to 5 Control resins (A-3) to (A-
5) were used separately, and the amounts of the curing agent "Epiclon B-57QJ (manufactured by Dainippon Ink and Chemicals, Φ, methyltetrahydrophthalic anhydride, which is liquid at room temperature)] and the curing accelerator 2 were added as shown in Table 2. -Ethyl-4-methyl-imidazole was added to obtain the epoxy resin composition of the present invention.The amount of the curing agent (B) at this time was the polyfunctional epoxy resin (
The ratio should be 1 mole per 1 epoxy group in A), and the amount of curing accelerator should be 1 part per 100 parts of the polyfunctional epoxy resin (A). did.

Thereafter, each epoxy resin composition was cured under the conditions described below to produce a cast plate.

Next, the physical properties of the cured products of each cast plate were tested, and the results shown in the table were obtained.

Curing conditions for the hardening process: The material was held at 100°C for 1 hour, then at 160°C for 2 hours, and then at 180°C for 2 hours.

Casting piece thickness: about 3. Comparative Examples 5 and 6 Solid [Epicron 3050J [bisphenol A type epoxy resin manufactured by Dainippon Ink & Chemicals ■; epoxy equivalent = 835, melting point -98°C]] and [Epicron N-67]
A casting plate was prepared in the same manner as in Examples 3 to 5, except that 3J and 3J were blended separately at a weight ratio of 80:20 and 70:30, and then the respective blends were used. Similarly, the physical properties of the cured product were evaluated. The results are summarized in Table 2.

Comparative Example 7 Examples 3 to 5 except that a blend of 80 parts of the control resin (A'-3) obtained in Reference Example 8 and 20 parts of Epiclon N-673J was used. A casting plate was prepared in the same manner as above, and the physical properties of the cured product were evaluated.The results are summarized in Table 2.

Comparative Example 8 Examples 3 to 5 except that a blend of 85 parts of the control resin (A'-4) obtained in Reference Example 9 and 15 parts of Epiclon N-740J was used. A casting plate was prepared in the same manner as above, and the physical properties of the cured product were evaluated.The results are summarized in Table 2.

* "Water absorption", which is the weight increase before and after treatment, expressed as a percentage, of the test piece after being treated in pressurized hot water at 121°C for a specified period of time was designated as the "Pressure Kutzker Test J (PCT)". .

*11 Two test pieces were subjected to PCT at 120°C for 4 hours.
The test piece was floated on molten solder at 60° C., and the appearance of the test piece, especially the presence or absence of “blister”, was visually evaluated.

○---------No abnormalities x-------1 "Blistering" ＊＊＊ The following is the percentage weight loss before and after the treatment when the product is placed in a dry product at IB□℃ for a specified period of time. It was displayed.

Claims (1)

[Scope of Claims] (A) The skeleton is at least one member selected from the group consisting of bisphenol A, bisphenol F, and tetrabromobisphenol A, and the epoxy equivalent is 170 to 80.
Bisphenol A, bisphenol A,
Bisphenol F and tetrabromobisphenol A
A polyfunctional epoxy resin having an epoxy equivalent of 200 to 2000 obtained by reacting at least one type of bisphenol (a-3) selected from the group consisting of (B) a curing agent for epoxy resin as essential components. An epoxy resin composition comprising: