JP2848241B2 - Epoxy resin composition for laminate and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an epoxy resin composition for a laminate used, for example, in electric and electronic equipment.

[0002]

2. Description of the Related Art Conventionally, a laminated board used for electric / electronic equipment is obtained by impregnating a base material such as a glass cloth with a varnish made of an epoxy resin composition, and then drying a plurality of prepregs obtained by drying. Furthermore, copper foil is arranged on the upper and lower sides of the copper foil, and then molded. In an epoxy resin composition used for this purpose, an amine-based curing agent such as dicyandiamide is generally used as a curing agent. In recent years, as the mounting density has increased, a laminate having better heat resistance than ever has been demanded, and phenol-based curing agents having better heat resistance than conventional amine-based curing agents have been studied. (For example, Japanese Unexamined Patent Publication No. Hei 3-79621) When manufacturing a laminated board, if the dried state of the prepreg is insufficiently heated, the resin flows out at the time of molding to cause a sheet thickness defect. If, for example, fine voids occur in the obtained laminate, so-called blurring defects occur,
In the case of a conventional amine-based curing agent, in order to prevent such defects, the drying conditions under which the prepreg having both the time until gelation suitable for lamination molding (hereinafter abbreviated as gelation time) and the melt viscosity are manufactured can be manufactured. Setting was possible.

However, in an epoxy resin composition using a phenolic curing agent, it is considered that three-dimensional crosslinking proceeds without the molecules of the epoxy resin or the like extending in a linear manner during the curing reaction. Since a phenomenon occurs in which gelation occurs immediately after the melt viscosity starts to increase, it is difficult to produce a prepreg so as to have both a gel time and a melt viscosity suitable for lamination molding, no matter how the prepreg production conditions are adjusted. Was.

[0004] The moldability and prepreg characteristics are modeled and explained. It is considered that they have the relationship shown in Table 1 below. When a phenolic curing agent is used, (b) or (d) in Table 1 is used. It is considered that only the prepreg in the state of was obtained.

[0005]

[Table 1]

In other words, when the melt viscosity is in an appropriate range, the sheet thickness defect caused by resin outflow can be prevented. On the other hand, by having an appropriate gel time, molding can be performed during molding. It is presumed that an appropriate flow state of the resin is obtained, and the fine voids in the laminate are completely filled with the resin, thereby preventing the blurring failure.

In the case of a conventional amine-based curing agent, both the gelation time and the melt viscosity can be set within appropriate ranges. However, when a phenol-based curing agent is used, one of them can be used. If the range is set to an appropriate range, the other part deviates from the appropriate range, and it is considered that the result is inferior in moldability.

[0008]

In view of the above circumstances, it is difficult to obtain a prepreg excellent in moldability by using an epoxy resin composition using a phenol-based curing agent, having an appropriate gel time and melt viscosity. It is an object of the present invention to solve the problem described above.

That is, the present invention provides an epoxy resin composition using a phenolic curing agent and capable of reducing the occurrence of molding defects (thickness or blurring) in the production process of a laminate, and a method for producing the same. The purpose is to do.

[0010]

The epoxy resin composition for a laminate according to claim 1 of the present invention has a skeleton represented by the following formula 4 in the molecule and has an epoxy equivalent of 1,000 or less. Epoxy resin containing 60% by weight or more of functional epoxy resin (a)

[0011]

Embedded image

(Wherein X represents a hydrogen atom or a halogen atom), a novolak resin (b) having a skeleton represented by the following formula 5 in the molecule:

[0013]

Embedded image

(Wherein R represents a hydrogen atom or an alkyl group having up to 9 carbon atoms), a phenoxy resin (c) having a skeleton represented by the following formula 6 and having a weight average molecular weight of 5,000 to 100,000: )

[0015]

Embedded image

(Wherein Y represents a hydrogen atom or a halogen atom, and n represents a positive number), a curing accelerator (d) and a solvent (e) are essential components, and an epoxy resin (a) and a
The pheno resin was added to 100 parts by weight of the total amount of the rack resin (b).
It is characterized in that 1.5 to 10 parts by weight of the xy resin (c) is blended .

The epoxy resin composition for a laminate according to the second aspect of the present invention is the epoxy resin composition for a laminate according to the first aspect, wherein the epoxy resin (a) having 1 epoxy equivalent is 0.6 to 1. It is characterized in that novolak resin (b) having 3 phenolic hydroxyl equivalents is blended.

The epoxy resin composition for a laminate according to claim 3 of the present invention is the epoxy resin composition for a laminate according to claim 1 or 2, wherein the novolak resin (b) is a resin.
Nol novolak resin, cresol novolak resin and
From p-xylene-phenol copolymerized novolak resin
At least one novolak tree selected from the group consisting of
It is characterized by being fat .

Further, the method for producing an epoxy resin composition for a laminate according to claim 4 of the present invention is characterized in that the phenoxy resin (c)
Is previously dissolved in a solvent (e) to form a solution, and the solution is used to produce an epoxy resin composition.

Hereinafter, the present invention will be described in detail. The epoxy resin (a) used in the present invention has a bifunctional compound having a skeleton represented by the above formula 4 in the molecule and having an epoxy equivalent of 1000 or less (having two epoxy groups in one molecule). 60% by weight or more of epoxy resin. In addition, having the skeleton represented by Formula 4 means that
This represents a so-called bisphenol A (including halogenated) epoxy resin. Bisphenol A
A bifunctional epoxy resin having an epoxy equivalent of 1000 or less has an appropriate melt viscosity, and in the curing reaction process, compared to a trifunctional or higher polyfunctional epoxy resin,
Since the molecule can extend linearly, it is characterized in that rapid three-dimensional crosslinking does not proceed. Therefore, when the above-mentioned bifunctional epoxy resin is used, it is easy to control the gel time of the prepreg depending on the prepreg production conditions, which is advantageous for achieving the object of the present invention.

The reason why the content of the bifunctional epoxy resin is limited to 60% by weight or more is that if the content of the bifunctional epoxy resin is less than 60% by weight, the remaining epoxy resin is monofunctional or trifunctional or more. In this case, if there are many monofunctional epoxy resin components, the heat resistance of the obtained laminate is impaired, and trifunctional or higher polyfunctional epoxy resin components are used. If the amount is too large, rapid three-dimensional crosslinking proceeds, and it is difficult to obtain a prepreg having an appropriate gel time and melt viscosity.

Specific examples of the above-mentioned bifunctional epoxy resin include compounds synthesized from bisphenol A or tetrabromobisphenol A and epichlorohydrin and having epoxy groups at both ends. The bisphenol A type bifunctional epoxy resin having an epoxy equivalent of 1000 or less and the phenoxy resin described below both have the basic skeleton represented by the above formula 4, but have a large molecular weight. Are different.

Novolak resin (b) used in the present invention
Is a compound having a skeleton represented by Formula 5 in the molecule, and examples thereof include a phenol novolak resin, a cresol novolak resin, and a p-xylene-phenol copolymerized novolak resin. These may be used alone. Two or more of them may be used in combination.

As for the amount of the novolak resin (b), 0.6 to 1.3 phenolic hydroxyl equivalents of the novolak resin (b) may be added to 1 epoxy equivalent of the epoxy resin (a). desirable. Outside of this range, there is a problem that the heat resistance of the obtained laminate is impaired.

Phenoxy resin (c) used in the present invention
Although there is no particular limitation, a linear polymer synthesized from bisphenol A or tetrabromobisphenol A and epichlorohydrin can be exemplified. This phenoxy resin (c) has a skeleton represented by the above formula 6, and has a weight average molecular weight of 5,000 to 10
0000 is desirable. Weight average molecular weight of 50
If it is less than 00, the melt viscosity is low, so that it is difficult to obtain a prepreg having an appropriate gel time and melt viscosity and improved moldability, and if it exceeds 100,000, the solubility in a solvent is poor, It becomes difficult to make a uniform solution of the resin composition. As for the blending amount of the phenoxy resin (c), 1.5 to 10 parts by weight of the phenoxy resin (c) may be blended with respect to 100 parts by weight of the total amount of the epoxy resin (a) and the novolak resin (b). desirable.
When the amount is less than 1.5 parts by weight, it is difficult to obtain a prepreg having an appropriate gel time and melt viscosity and having improved moldability. There is a problem that strength (bending strength, etc.) is reduced.

The curing accelerator (d) used in the present invention is not particularly limited, but includes 1,8-diaza-bicyclo (5,4,0) undecene-7, triethylenediamine,
Tertiary amines such as benzyldimethylamine, imidazoles such as 2-methylimidazole, 2-ethyl-4-methylimidazole and 2-phenylimidazole, and organic phosphines such as tributylphosphine and triphenylphosphine (phosphorus-based curing accelerator) And tetraphenylboron salts such as tetraphenylphosphonium tetraphenylborate and triphenylphosphine tetraphenylborate.

The solvent (e) used in the present invention includes:
Any solvent can be used as long as it can provide a uniform solution of the resin composition, and is not particularly limited. Ketones such as acetone and methyl ethyl ketone, ethers such as ethylene glycol monomethyl ether, and aromatic compounds such as benzene and toluene Group hydrocarbons and the like.

In the process for producing an epoxy resin composition for a laminate, if the solid phenoxy resin (c) is mixed with other components and dissolved in the solvent (e), the phenoxy resin (c) Is difficult to dissolve, and it is difficult to obtain an epoxy resin composition having a uniform composition. When a prepreg is manufactured using an epoxy resin composition (varnish) having a non-uniform composition, a phenomenon in which the dispersion of the resin content in one obtained prepreg becomes as large as ± 3% or more in some cases occurs. . When a laminate is formed using a prepreg having a large variation in resin content, the variation in the thickness of the obtained laminate becomes large, which causes a practical inconvenience such as a failure to reliably connect to a connector.

In the invention relating to the production method of the present invention, the phenoxy resin (c) is dissolved in the solvent (e) in advance to form a solution, and the epoxy resin composition is produced using this solution. The variation of the resin content within one obtained prepreg is, for example, ± 2% or less,
It becomes possible to fall within a good range. The phenoxy resin (c) may be heated when dissolved in the solvent (e) in advance.

[0030]

In the present invention, the inclusion of a phenoxy resin having a specific weight average molecular weight in the epoxy resin composition serves to increase the melt viscosity of the resin component in the epoxy resin composition. Therefore, by adjusting the blending amount of the phenoxy resin and adjusting the production conditions (drying conditions) of the prepreg, it becomes possible to obtain a prepreg having an appropriate gel time and melt viscosity and improved moldability. That is, by adjusting the blending amount of the phenoxy resin, it has become possible to change only the melt viscosity without substantially changing the gel time of the prepreg, which has been difficult in the past.

The use of a phenoxy resin having a halogen atom such as bromine in the molecule as the phenoxy resin has an effect of imparting flame retardancy to the obtained laminate.

Further, the method of dissolving the phenoxy resin in a solvent in advance to form a solution and producing the epoxy resin composition using this solution has the effect of obtaining an epoxy resin composition (varnish) having a uniform composition. I do.

[0033]

The present invention will be described below based on examples and comparative examples.

As the epoxy resin (a), the following five types of epoxy resins were used in the proportions shown in Tables 2, 3 and 4. Epoxy resin 1—a bifunctional bisphenol A type epoxy resin having a skeleton represented by Formula 4 and an epoxy equivalent of 500 [manufactured by Yuka Shell Epoxy Co., Ltd.
Trade name: Epicoat 1001] Epoxy resin 2—a bifunctional bisphenol A-type epoxy resin having a skeleton represented by Formula 4 and an epoxy equivalent of 180 [manufactured by Yuka Shell Epoxy Co., Ltd.
Product name: Epicoat 828] Epoxy resin 3—a bifunctional tetrabromobisphenol A type epoxy resin having a skeleton represented by the above formula 4 and an epoxy equivalent of 400 [manufactured by Sumitomo Chemical Co., Ltd. Name ESB400] Epoxy resin 4-a bifunctional tetrabromobisphenol A type epoxy resin having a skeleton represented by the above formula 4 and having an epoxy equivalent of 500 [DER511, a product of Dow Chemical Co.] epoxy resin 5--A polyfunctional cresol novolak-type epoxy resin not having a skeleton represented by Formula 4 and having an epoxy equivalent of 200, and mainly having three or more functionalities [trade name: YDCN702P, manufactured by Toto Kasei Co., Ltd.] ]

As the novolak resin (b) having a skeleton represented by the above formula (5) in the molecule, the following two phenolic curing agents are blended in the proportions shown in Tables 2, 3 and 4. used. Tables 2, 3 and 4 show the ratio of the reactive groups of the epoxy resin (a) and the novolak resin (b) as the equivalent ratio of epoxy group / phenolic hydroxyl group. -1 phenolic curing agent 1-phenol novolak resin having a hydroxyl equivalent of 105 (manufactured by Arakawa Chemical Industries, Ltd.
Brand name Tamanol 752] -2 phenolic curing agent 2--p-xylene-phenol copolymerized novolak resin having a hydroxyl equivalent of 180 [Mirex 225, manufactured by Mitsui Toatsu Chemicals, Inc.]

As the phenoxy resin (c) having a skeleton represented by the above formula 6, the following two kinds were blended and used in proportions shown in Tables 2, 3 and 4. Phenoxy resin 1-weight average molecular weight is 42600, phenoxy resin wherein Y in the formula 6 is a hydrogen atom [PKHH, manufactured by Union Carbide Co., Ltd.] Phenoxy resin 2-weight average molecular weight is 52,500, Phenoxy resin in which Y in Formula 6 is a hydrogen atom [YP50 (trade name, manufactured by Toto Kasei Co., Ltd.)] Phenoxy resin 3-a skeleton in which Y in Formula 6 is a bromine atom Phenoxy resin having the product name (YPB40, manufactured by Toto Kasei Co., Ltd.)
Bromine content 20% by weight]

2-Ethyl 4-methylimidazole was used as the curing accelerator (d), and methyl ethyl ketone was used as the solvent (e) in the proportions shown in Tables 2, 3 and 4, respectively.

Using the above-mentioned raw materials, in Example 1 and Comparative Examples 1 and 2, the raw materials were simultaneously mixed and dissolved to obtain an epoxy resin composition. On the other hand, for Examples 2 to 10, the phenoxy resin was previously dissolved in a solvent to form a solution,
Next, this solution and other raw materials were mixed and dissolved to obtain an epoxy resin composition.

The varnish-like epoxy resin composition thus obtained was added to a glass cloth [manufactured by Asahi Schwebel Co., Ltd., product no.
628W] and then dried at 150 ° C. to prepare a prepreg having a resin content of about 45% by weight and a thickness of about 0.2 mm. The drying time at this time is such that the resin composition has a melt viscosity at 130 ° C. (minimum melt viscosity measured at 130 ° C.) of 300 to 5 at the stage of forming the prepreg.
The setting was made for each of the resin compositions so as to be 00 poise. 130 ° C for the prepreg prepared above
, The melt viscosity at 130 ° C., and the dispersion of resin content in one prepreg were measured. The results are shown in Tables 2, 3 and 4. In addition, the above-mentioned melt viscosity was measured by a Koka type flow tester by rubbing off the resin component adhering to the prepreg, and the dispersion of resin content was obtained by collecting test pieces from different positions of one prepreg, and performing each test. The resin content of each test piece was calculated by subtracting the weight of only the glass cloth of the size equivalent to the test piece from the weight of the test piece, and the variation (Rmax) was obtained from the resin content of each obtained test piece.

Next, eight prepared prepregs were stacked, sandwiched between metal plates via a release film, and pressed and heated under the following conditions to form a laminate. First step: pressure 5 kg / cm ² , temperature 120 ° C., time 5 minutes Second step: pressure 40 kg / cm ² , temperature 120 ° C.
Time 15 min third step: hold at a pressure 40kg / cm ^2, 170
4th step: pressure 40 kg / cm ² , temperature 170 ° C.
Time 60 minutes Fifth step: Hold pressure 40 kg / cm ² and cool to room temperature

With respect to the laminate prepared as described above, the presence or absence of so-called blurring defects, in which fine voids were formed in the laminate, was visually observed. The results are shown in Tables 2, 3 and 4. In addition, a test piece of a predetermined size was cut out from the laminated plate, and the flame retardancy was checked in accordance with the UL standard, and it was determined whether the flame retardancy was equivalent to V-0 of the UL standard. 3 and Table 4.

[0042]

[Table 2]

[0043]

[Table 3]

[0044]

[Table 4]

From the results of Tables 2, 3 and 4, the following was confirmed. Comparison between Example 1 and Comparative Example 1 and Example 3
From the comparison between Comparative Example 2 and Comparative Example 2, when the prepreg did not contain a phenoxy resin, if the prepreg had a melt viscosity of 300 to 500 (an appropriate melt viscosity range), the gel time was 1
It has become short and the laminating board obtained by lack of fluidity of the resin at the time of molding has suffered from blurring failure, but the one containing phenoxy resin has a melt viscosity of prepreg of 300-500. And the gel time is 15 ~
Since the gelation time can be set to an appropriate time of 25 minutes, no blurring failure occurs. (The appropriate gelation time is estimated to be 15 to 30 minutes.) In Examples 4 to 7 and Example 10 using the brominated phenoxy resin 3, excellent passability of V-0 was obtained. Has flammability.

From the comparison between Example 1 and Example 2, a phenoxy resin was previously dissolved in a solvent to form a solution, and then this solution and another raw material were mixed and dissolved to obtain an epoxy resin composition. In the prepreg of Example 2, the dispersion of the resin content is within a good (small) range of ± 1% or less.

[0047]

Since the epoxy resin composition for a laminate according to the present invention according to claims 1 to 3 is constituted as described above,
According to these epoxy resin compositions for laminates, it is possible to obtain a prepreg having both an appropriate gel time and melt viscosity, and thus having excellent moldability. That is, in the production of a laminated board using a phenolic curing agent, the use of the epoxy resin composition for a laminated board of the present invention makes it possible to reduce molding defects (defective thickness or blurring).

According to the method for producing an epoxy resin composition for a laminate according to the fourth aspect, an epoxy resin composition (varnish) having a uniform composition can be obtained, so that a prepreg having a small variation in resin content can be produced. This makes it possible to reduce the variation in the thickness of the laminated board.

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Yukihiro Hatta 1048 Odomo Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Works, Ltd. (56) References JP-A-3-37256 (JP, A) JP-A-2-60918 (JP, a) JP Akira 63-113084 (JP, a) JP flat 4-59819 (JP, a) JP flat 3-79621 (JP, a) (58 ) investigated the field (Int.Cl. ⁶ , DB name) C08G 59/22 C08G 59/62 C08J 5/24 B32B 27/04 B32B 27/38

Claims (4)

(57) [Claims] 1. An epoxy resin (a) having a skeleton represented by the following formula 1 in a molecule and containing 60% by weight or more of a bifunctional epoxy resin having an epoxy equivalent of 1000 or less. (Wherein X represents a hydrogen atom or a halogen atom), a novolak resin (b) having a skeleton represented by the following formula 2 in the molecule: (In the formula, R represents a hydrogen atom or an alkyl group having up to 9 carbon atoms.) Having a skeleton represented by the following formula 3, and having a weight average molecular weight of 5
Phenoxy resin (c) having a molecular weight of 000 to 100,000 (Where Y represents a hydrogen atom or a halogen atom, and n represents a positive number), a curing accelerator (d) and a solvent (e) as essential components ,
Total amount of xy resin (a) and novolak resin (b) 100
1.5 to 10 parts by weight of phenoxy resin (c) based on parts by weight
An epoxy resin composition for a laminated board to be blended in parts by weight . 2. The epoxy resin composition for a laminate according to claim 1, wherein a novolak resin (b) having a phenolic hydroxyl group equivalent of 0.6 to 1.3 is blended with respect to one epoxy equivalent of the epoxy resin (a). 3. The phenolic resin according to claim 1, wherein the novolak resin (b) is a phenolic resin.
Volak resin, cresol novolak resin and p-xy
Of the group consisting of len-phenol copolymerized novolak resins
The epoxy resin composition for a laminate according to claim 1 or 2, which is at least one kind of novolak resin selected from the group . 4. The phenoxy resin (c) is added to a solvent (e) in advance.
The method for producing an epoxy resin composition for a laminate according to any one of claims 1 to 3, wherein the epoxy resin composition is produced using the solution.