JPH0745561B2 - Epoxy resin composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a novel and useful epoxy resin composition, and more specifically, to a bifunctional epoxy resin having a specific bisphenol group as a skeleton and a bisphenol A novolak type epoxy resin composition. A mixture with an epoxy resin, a polyfunctional epoxy resin obtained by reacting such a specific bisphenol as an essential base resin component, on the other hand, a curing agent for epoxy resin as an essential curing agent component, heat resistance, water resistance The present invention relates to a resin composition having excellent cured product properties such as toughness, mechanical strength and flexibility, and therefore suitable for lamination, molding, coating or adhesion.

[Problems to be Solved by Conventional Techniques and Inventions] Since bisphenol A type epoxy resins, which are the most general-purpose ones, are bifunctional, they may lack heat resistance depending on the application.

In order to improve the heat resistance in such a case, a polyfunctional novolac type epoxy resin is often used together.

Further, in the field where flame retardancy is required, a brominated epoxy resin containing tetrabromobisphenol A as a single bisphenol component or a brominated epoxy resin which is a co-condensation of tetrabromobisphenol A and bisphenol A is generally used. When the heat resistance is also required, the arrow tension novolac type epoxy resin is often used together.

In addition, a so-called bisphenol F type epoxy resin having a bisphenol F skeleton in a part or all of the bisphenol A skeleton is also used, although it is rare.

In any case, if a novolac type epoxy resin is used in combination with a bifunctional epoxy resin using various bisphenols as described above for the purpose of imparting heat resistance, this heat resistance improvement is sure, but On the other hand, since the cured product tends to be hard and brittle, and flexibility tends to decrease, it is problematic to increase the amount of the novolac type epoxy resin used together considering only heat resistance, and also in terms of cost. Is often disadvantageous in general.

For example, in so-called G-10 grade, which is not flame-retarded in an epoxy resin laminated plate, a bisphenol A type solid epoxy resin is used as a main raw material component, and a phenol novolac type or gresol novolac type epoxy resin is provided with heat resistance. As a component, a mixture of these two components is often used.

On the other hand, the flame-retarded FR-4 grade is based on a bisphenol A type liquid epoxy resin and is modified with tetrabrom bisphenol A to obtain a low bromine type with a bromine content of at most 20 to 30% by weight. A form in which an epoxy resin is used as a main raw material component, and a phenol novolac type epoxy resin, a cresol novolac type epoxy resin, or the like is mixed with the main component is also used for the purpose of imparting heat resistance.

However, in the application of such a laminated board, by using a novolac type epoxy resin together, the dimensional stability of the laminated board becomes poor, or the drill resistance becomes poor because it is hard and brittle, and insulation Even in the field of powder coating materials and molding materials, the fact that similar resins are used together has caused the same problems.

[Means for solving problems]

However, in view of the existence of various drawbacks in the prior art as described above, the present inventors not only have heat resistance,
As a result of diligent research to obtain an epoxy resin composition balanced in various properties such as mechanical strength, water resistance and flexibility, it is possible not only to blend a novolac type epoxy resin with a bifunctional epoxy resin, When a bifunctional epoxy resin and a novolac type epoxy resin, especially a bisphenol A novolac type epoxy resin, are made to have such a structure that they are grafted, an extremely effective epoxy resin for the above purpose is obtained. It was found that a composition was obtained, and the present invention was completed.

The reason why the novolac type epoxy resin used in the present invention is limited to the bisphenol A novolac type epoxy resin is that the heat resistance and water resistance are higher than those obtained by grafting the phenol novolac type epoxy resin or the cresol novolac type epoxy resin in the same way. This is because the sex is much better. This is because the bisphenol A novolac type epoxy resin itself is superior in heat resistance and water resistance to the phenol novolac type epoxy resin or the cresol novolac type epoxy resin, and the novolac type epoxy resin and the bifunctional epoxy resin (a In the bisphenol A novolac type epoxy resin, the reactivity with the bisphenol (a-3) used for grafting with -1) is higher than that of the phenol or cresol novolac type epoxy resin, and as a result, the novolac type epoxy resin is obtained. It is considered that one of the reasons is that the grafting ratio of the above-mentioned to the bifunctional epoxy resin is higher.

That is, the present invention provides a bifunctional epoxy resin (a-1) having an epoxy equivalent of 170 to 800, which has (A) at least one bisphenol selected from the group consisting of bisphenol A, bisphenol F and tetrabromobisphenol A as a skeleton. )When,
The average number of glycidyl groups in one molecule obtained by reacting bisphenol A novolak resin derived from bisphenol A and formaldehyde with epichlorohydrin is
A mixture of 2.3 to 10 bisphenol A novolac type epoxy resin (a-2) is reacted with at least one bisphenol (a-3) selected from the group consisting of bisphenol A, bisphenol F and tetrabromobisphenol A. Obtained, the epoxy equivalent is 200
The present invention provides an epoxy resin composition containing, as essential components, a polyfunctional epoxy resin of about 2,000 and a curing agent (B) for epoxy resin.

Here, the bifunctional epoxy resin (a-1) used for preparing the polyfunctional epoxy resin (A) which is the first essential component constituting the composition of the present invention is a bisphenol (a-3). At least one compound selected from the group consisting of bisphenol A, bisphenol F, and tetrabromobisphenol A and epichlorohydrin are used, and known compounds such as those described in "Epoxy Resin" published by Shokoido Co., Ltd. A liquid or solid (brominated) epoxy resin having two glycidyl ethers in the same molecule, which is easily obtained by the method,
Alternatively, based on the epoxy resin thus obtained, at least one selected from bisphenol A, bisphenol F and tetrabromobisphenol A used as bisphenols (a-3).
The following general formula, obtained by reacting certain compounds by known methods, such as those described in "Epoxy Resins" above It means a (brominated) epoxy resin having a structure as shown in (3), and is a general term for resins having a bisphenol skeleton and having an epoxy equivalent of 170 to 800, preferably 190 to 500.

The polyfunctional epoxy resin (A) is a mixture of the thus obtained bifunctional epoxy resin (a-1) and a bisphenol A novolac type epoxy resin (a-2) as described below with respect to a bisphenol (a). -3) is reacted to introduce a novolac structure into the molecule, so long as the bisphenol (a-3) is used in a small amount, the bisphenol (a-3) is used. The effect of the grafting of is too short.

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 the desired polyfunctional epoxy resin (A) does not have too high molecular weight. The amount of the bisphenol (a-3) used also has a role of increasing the molecular weight,
After all, it must be suppressed, but as a result, the effect of grafting is necessarily diluted by that amount.

Therefore, the molecular weight of the bifunctional epoxy resin (a-1) to be used is preferably low, except when the polyfunctional epoxy resin (A) having a relatively high molecular weight is to be obtained.

Next, the above-mentioned bisphenol A novolac type epoxy resin (a-2) is a known bisphenol A novolac type resin obtained by combining bisphenol A and formaldehyde with epichlorohydrin, as described in "Epoxy Resin" above. It is a novolac type epoxy resin having an average of 2.3 to 10, preferably 4 to 8 glycidyl groups in one molecule, which is obtained by the reaction by the method (1).

And, as the polyfunctional epoxy resin (A), those having an epoxy equivalent of 200 to 2,000, preferably 300 to 1,200 are usually used. The bifunctional epoxy resin (a) mentioned above, which is used in preparing this, is used. -1), the bisphenol A novolac type epoxy resin (a-2) and the bisphenols (a-3) as raw material components are used in different proportions depending on the use and required performance of the composition of the present invention. If, for example, heat resistance is to be emphasized as much as possible, the ratio of the bisphenol A novolac type epoxy resin (a-2) should be increased, and the grafting rate to this resin (a-2) should be increased. The amount of bisphenols (a-3) also needs to be increased in order to increase the amount of bisphenol.

In addition, since impregnability is important when obtaining the composition of the present invention for a laminated board, the molecular weight of the polyfunctional epoxy resin (A) cannot be increased so much, as described above. Bifunctional epoxy resin (a-
It should be noted that 1) the molecular weight of itself should be kept as low as possible, while the amount of bisphenol (a-3) used should be raised to an appropriate level.

Furthermore, when it is intended for use as a powder coating material, it is difficult to use a substance having a too low molecular weight or a substance having a low melting point in terms of blocking. Therefore, the polyfunctional epoxy resin (A) is used.
It is necessary to increase the molecular weight of the bisphenols (a-3) to a certain extent. In such a case, if the too low molecular weight difunctional epoxy resin (a-1) is used, the bisphenols (a-3)
The amount of bisphenol A used at the same time increases
When the amount of the novolac type epoxy resin (a-2) used is large, the danger of gelation of the polyfunctional epoxy resin (A) also comes out, so it should be noted.

Therefore, in such a case, bisphenols (a-
In order to reduce the amount of 3) used, it becomes necessary to use the bifunctional epoxy resin (a-1) having a higher molecular weight.

In any case, what should be particularly noted in the design for obtaining the resin (A) having the desired molecular weight and the desired heat resistance is to graft onto the bisphenol A novolac type epoxy resin (a-2). It is essential that the degree of gelation is not too low, and, conversely, that gelation does not occur beyond the desired grafting range, which requires sufficient preliminary experiments. At the same time, compared to the conventional simple blending method, it is important to design while confirming the effects of such grafting. As the usage ratio of each raw material component in the normal case,
The weight ratio (a-1) / (a-2) is 90/10 to 60/40,
{(A-1) + (a-2)} / (a-3) is 100/20 to 10
It is in the range of 0/70.

Thus, each difunctional epoxy resin (a-
1), bisphenol A novolac type epoxy resin (a
-2) and the reaction using bisphenols (a-3), the above-mentioned "epoxy resin" and known methods such as those described in JP-A-48-83199. For example, an alkaline hydroxide such as sodium hydroxide, a tertiary amine such as triethylamine or benzyldimethylamine, a quaternary ammonium salt such as tetramethylammonium chloride, an imidazole compound, triphenylphosphine, etc. can be used as a catalyst. ~ 180
By reacting at 0 ° C., the intended polyfunctional epoxy resin (A) having excellent heat resistance, mechanical strength, water resistance and flexibility can be obtained.

In the present invention, the use of the polyfunctional epoxy resin (A) obtained as described above means that the bisphenol A novolac type epoxy resin (a-2) is preliminarily grafted with this resin (a-2). In addition to the polyfunctional epoxy resin (A) in the present invention obtained by adopting the method, on the other hand, a novolac type epoxy resin such as a phenol novolac type epoxy resin and a cresol novolac type epoxy resin including this resin (a-2). In the case of a conventional epoxy blend obtained by simply blending, when the cured products of these two resins are designed to have the same heat resistance, such as heat distortion temperature and glass transition point (Tg). However, in the former method, that is, when the polyfunctional epoxy resin (A) is used, this bisphenol A The amount of the rack type epoxy resin (a-2) used is much smaller than that of the latter method, that is, the case of using the epoxy blend, and as a result, the toughness is naturally the former method. It can be said that it is really advantageous because of the surprising result that the water resistance is excellent and the water resistance is also excellent in the former case.

Also, when the polyfunctional epoxy resin (A) of the present invention is used and the conventional simple blend is used, the novolac type epoxy resin is designed to have the same amount of use, respectively, The cured product according to the present invention is far superior in heat resistance, mechanical strength and water resistance, and is also tough.

Furthermore, in the present invention, by limiting the novolac type epoxy resin to be grafted to the bisphenol A novolac type epoxy resin, compared with the case where another novolac type epoxy resin such as phenol or cresol novolac type epoxy resin is grafted. However, it has been found that a product having even better heat resistance and water resistance can be obtained.

On the other hand, as the above-mentioned 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 maleic anhydride or hexahydrophthalic anhydride. In addition to acid anhydrides such as pyromellitic dianhydride, latent hardeners such as dicyandiamide, imidazole, BF ₃ -amine complex or guanidine derivative can be mentioned.

When using each of these compounds as a curing agent, it is often necessary to further use a curing accelerator together. In such a case, tertiary amines such as dimethylbenzylamine, imidazole, etc. It is needless to say that known and commonly used compounds such as a class or various metal compounds can be applied.

The polyfunctional epoxy resin (A) in the present invention
The term polyfunctional shall mean a resin with a functionality greater than 2 on average.

Thus, the epoxy resin composition of the present invention comprises the above-mentioned polyfunctional epoxy resin (A) and both essential components which are the curing agent for epoxy resin (B), and the solid content of the resin (A) component is 100%.
It is obtained by mixing in a ratio of 2 to 70 parts by weight with respect to parts by weight. However, it should be noted that such a compounding ratio greatly varies depending on the type of the curing agent (B) component used.

The composition of the present invention thus obtained can further be mixed with various additives such as a filler and a colorant, if necessary, and tar, pitch, amino resin, alkyd resin, phenol resin, or the like. Can also be used together.

〔The invention's effect〕

The epoxy resin composition of the present invention is excellent in heat resistance, mechanical strength, water resistance and the like, and also provides a very useful cured product that is tough and not brittle.

Due to the combination of these properties, the composition of the present invention is extremely useful for a wide range of applications such as laminate materials, molding materials, coating materials and adhesives.

〔Example〕

Next, the present invention will be described in detail with reference to Reference Examples, Examples and Comparative Examples. In the following, all parts and% are based on 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 and Chemicals, Inc.] having an epoxy equivalent of 190 and bisphenol A To a mixture of 13 parts of novolac type epoxy resin (epoxy equivalent = 210, softening point = 78 ° C., average glycidyl group number = 6.5, hereinafter referred to as bisphenol A novolac type epoxy resin (I)), 34 parts of tetrabromobisphenol A was added. Plus 120
The mixture was heated to 0 ° C. and stirred, and then 2-methyl-imidazole was added.
When 0.01 part was added and reacted at 150 ° C. for 4 hours, a solid target resin having an epoxy equivalent of 475 and a bromine content of 20% was obtained. Hereinafter, this is abbreviated as resin (A-1).

Reference Example 2 (Same as above) Reference Example 1 except that the amount of "Epiclone 850" used was changed from 53 parts to 56 parts and the amount of bisphenol A novolac type epoxy resin (I) was changed from 13 parts to 10 parts. Similarly, the epoxy equivalent is 471 and the bromine content is 20.
% Solid resin was obtained. Hereafter, this is referred to as resin (A-
2) is abbreviated.

Reference Example 3 (Same as above) Instead of the bisphenol A novolac type epoxy resin (I), a bisphenol A novolac type epoxy resin (II) having an epoxy equivalent of 208, a softening point of 68 ° C. and an average number of glycidyl groups of 5.0 was used. A solid type target resin having an epoxy equivalent of 470 and a bromine content of 20% was obtained in the same manner as in Reference Example 1 except for the above. Hereinafter, this is abbreviated as resin (A-3).

Reference Example 4 (same as above) Same as Reference Example 1 except that 28 parts of bisphenol A was added to a mixture of 52 parts of "Epiclone 850" and 20 parts of bisphenol A novolac type epoxy resin (I). Thus, a target resin having an epoxy equivalent of 830 and a softening point of 95 ° C. was obtained. Hereinafter, this is a resin (A-
4) is abbreviated.

Reference Example 5 (Same as above) 65 of "Epiclone 152" [Tetrabrom bisphenol A type epoxy resin manufactured by Dainippon Ink and Chemicals, Inc .; epoxy equivalent = 360, softening point = 60 ° C, bromine content = 47%]
Parts and bisphenol A novolac type epoxy resin (I)
15 parts of the above, except that 20 parts of tetrabromobisphenol A was added, and the epoxy equivalent was 540, the softening point was 83 ° C., and the bromine content was the same as in Reference Example 1. 42% of the target resin was obtained. Hereinafter, this is abbreviated as resin (A-5).

Reference Example 6 [Preparation Example of Polyfunctional Epoxy Resin (A ') for Control] Semi-solid type "Epiclone N-740" [Dainippon Ink and Chemicals (instead of 13 parts of bisphenol A novolac type epoxy resin (I)] Co., Ltd. phenol novolac type epoxy resin; epoxy equivalent = 180, average glycidyl group number = 4.
In the same manner as in Reference Example 1 except that 13 parts of [0] was used, a solid control resin having an epoxy equivalent of 450 and a bromine content of 20% was obtained. Hereinafter, this is abbreviated as resin (A'-1).

Reference Example 7 (same as above) Instead of 13 parts of bisphenol A novolac type epoxy resin (I), "Epiclon N-680" (cresol novolac type epoxy resin manufactured by the same company; epoxy equivalent = 210,
Epoxy equivalent was 473 in the same manner as in Reference Example 1 except that 13 parts of softening point = 84 ° C. and average glycidyl group number = 6.6) were used.
A solid control resin having a bromine content of 20% was obtained. Hereinafter, this is abbreviated as resin (A'-2).

Reference Example 8 (same as above) The epoxy equivalent was 831 in the same manner as in Reference Example 4 except that the same amount of "Epiclone N-680" was used instead of the bisphenol A novolac type epoxy resin (I).
And a control resin having a softening point of 93 ° C. was obtained. Hereinafter, this is abbreviated as resin (A'-3).

Reference Example 9 [Preparation Example of Control Bifunctional Epoxy Resin (A ″)] A mixture of 46 parts of “Epiclone 850” and 34 parts of tetrabromobisphenol A was heated to 120 ° C., stirred, and further treated with 2-methyl. 0.01 part of imidazole was added and reacted at 150 ° C. for 4 hours to obtain a solid control resin having an epoxy equivalent of 695 and a bromine content of 25%. Hereinafter, this is abbreviated as resin (A ″ -1).

Reference Example 10 (same as above) In the same manner as in Reference Example 8 except that the amounts of "Epiclone 850" and tetrabromobisphenol A used were changed to 52 parts and 35 parts, respectively, the epoxy equivalent was 615, and the bromine content was A 23% solid control resin was obtained. Hereinafter, this is abbreviated as resin (A ″ -2).

Reference Example 11 (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 0.01 part of 2-methyl-imidazole was further added to the mixture at 150 ° C for 4 hours. After reacting for a time, the epoxy equivalent is 687 and the softening point is 86.
A control resin having a bromine content of 49% at 0 ° C. was obtained. Hereinafter, this is abbreviated as resin (A ″ -3).

Examples 1 to 3 and Comparative Examples 1 to 2 Resins (A-1), (A-2), (A-3), and (A ′) obtained in Reference Examples 1 to 3 and Reference Examples 6 to 7, respectively. −
1) and (A′-2) were separately dissolved with methyl ethyl ketone, and then the amounts of the curing agent dicyandiamide and the curing accelerator dimethylbenzylamine, which had been previously dissolved in methyl cellosolve, shown in Table 1 below were added, A mixed solution having a nonvolatile content (NV) of 55% was prepared. The amount of the curing agent (B) at this time is such that it is 0.25 mol with respect to one epoxy group in the polyfunctional epoxy resin (A),
On the other hand, as the amount of the curing accelerator, the polyfunctional epoxy resin (A)
The ratio was 0.2 part with respect to 100 parts of solid content.

Then, the mixed solution was used and cured under the following conditions to prepare a laminated plate.

Then, when the physical properties of the cured product were tested for each laminate,
The results shown in the table were obtained.

Laminated plate manufacturing conditions Base material: "WE-18K-104-BZ2" [glass cloth manufactured by Nittobo Co., Ltd.] Number of plies: 9 Resin content: about 40% Comparative Example 3 Using a mixture (mixed solution) of 80 parts of the control resin (A ″ -1) obtained in Reference Example 9 and 20 parts of “Epiclone N-740”. A laminated board was produced in the same manner as in Example 1 except that the above was changed to, and the cured product properties were evaluated in the same manner. The results are shown in Table 1.

Comparative Example 4 A laminated sheet was prepared in the same manner as in Example 1 except that 87 parts of the control resin (A ″ -2) obtained in Reference Example 10 and 13 parts of “Epiclone N-740” were used. Was prepared, and the physical properties of the cured product were evaluated in the same manner. The results are shown in Table 1.

Comparative Example 5 A test was conducted in the same manner as Comparative Example 3 except that the same amount of "Epiclone N-680" was used instead of "Epiclone N-740". The results are shown in Table 1.

Comparative Example 6 A test was conducted in the same manner as Comparative Example 4 except that the same amount of "Epiclone N-680" was used instead of "Epiclone N-740". The results are shown in Table 1.

Comparative Example 7 A test was performed in the same manner as in Comparative Example 4 except that the same amount of bisphenol A novolac type epoxy resin was used instead of “Epiclone N-740”. The results are shown in Table 1.

Examples 4-5 and Comparative Example 8 Control resins (A) obtained in Reference Examples 4-5 and Reference Example 8
-4), (A-5) and (A'-3) are used separately,
The amount of the curing agent shown in Table 2 is "Epiclone B-570" (manufactured by Dainippon Ink and Chemicals, Inc., methyl tetrahydrohetalic anhydride that is liquid at room temperature) and a curing accelerator 2-ethyl-4-.
Methyl-imidazole was added to obtain an epoxy resin composition of the present invention. In this case, the amount of the curing agent (B) is 1 with respect to one epoxy group in the polyfunctional epoxy resin (A).
On the other hand, the amount of the curing accelerator was set to 1 part with respect to 100 parts of the polyfunctional epoxy resin (A).

Then, each epoxy resin composition was cured under the following conditions to prepare a casting plate.

Next, when the physical properties of the cured product were tested for each casting plate, the results shown in the same table were obtained.

Casting plate manufacturing conditions Curing conditions: 100 ° C. for 1 hour, 160 ° C. for 2 hours, and 180 ° C. for 2 hours.

Cast piece thickness: about 3 mm Comparative Examples 9 and 10 Solid bisphenol A type epoxy resin "Epcron 3050" for comparison [Dainippon Ink and Chemicals, Inc., epoxy equivalent = 835, softening point = 98 ° C] "Epiclon N-680" is blended separately in a weight ratio of 80:20 and 70:30,
Next, a cast plate was prepared in the same manner as in Example 4 except that each blended product was used, and the physical properties of the cured product were evaluated in the same manner. The results are shown in Table 2.

Comparative Example 11 A blend of "Epiclone 3050" and bisphenol A novolac type epoxy resin (I) in a weight ratio of 80:20 was tested in the same manner as in Comparative Example 9. The results are shown in Table 2.

Comparative Example 12 Same as Example 4 except that a blend of 85 parts of the control resin (A ″ -3) obtained in Reference Example 11 and 15 parts of “Epiclone N-740” was used. Then, a casting plate was prepared and the physical properties of the cured product were evaluated. The results are shown in Table 2.

Claims (1)

[Claims] 1. A bifunctional epoxy resin (a-1) having an epoxy equivalent of 170 to 800, which has (A) a skeleton of at least one bisphenol selected from the group consisting of bisphenol A, bisphenol F and tetrabromobisphenol A. ) And a bisphenol A novolac type epoxy resin (a-2) having an average number of glycidyl groups in a molecule of 2.3 to 10 obtained by reacting bisphenol A novolak resin derived from bisphenol A and formaldehyde with epichlorohydrin. A polyfunctional epoxy resin having an epoxy equivalent of 200 to 2,000, obtained by reacting with at least one bisphenol (a-3) selected from the group consisting of bisphenol A, bisphenol F and tetrabromobisphenol A; B) With a curing agent for epoxy resin Comprising as essential components, an epoxy resin composition.