JPH0985890A - Manufacture of laminated board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a laminated board which makes it possible to improve the preservation stability of a prepreg without extending the forming time. SOLUTION: The method for manufacturing a laminated board has the steps of laminating a plurality of prepregs obtained by impregnating a base material with epoxy resin, and thermally curing it, and comprises the step of alternately combining and laminating a first prepreg (A) containing epoxy resin and curing agent and obtained by impregnating it with varnish containing curing accelerator of the ratio of less than 0.05 pt.wt. to 100 pts.wt. of epoxy resin and a second prepreg (B) containing epoxy resin and curing accelerator and obtained by impregnating it with varnish containing curing accelerator of the ratio of less than 1.0 pt.wt. to 100 pts.wt. of epoxy resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a laminated board used as a material for a printed wiring board or the like, which is a component of electronic equipment or the like.

[0002]

2. Description of the Related Art Conventionally, a laminated board is manufactured by a method of laminating a plurality of prepregs impregnated with a varnish containing an epoxy resin, a curing agent and a curing accelerator on a substrate such as a glass cloth, and curing them by heating. . In such a manufacturing method, it is strongly required that the storage stability of the prepreg is good in order to stabilize the quality of the laminated plate, and in order to efficiently manufacture the laminated plate, the time required for heat curing, That is, it is also required to shorten the molding time. However, if an attempt is made to increase the reaction rate of the resin component contained in the prepreg by means such as increasing the amount of the curing accelerator in an attempt to shorten the molding time, there arises a problem that the storage stability of the prepreg is impaired. At the same time it was difficult to satisfy.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide:
It is an object of the present invention to provide a method for producing a laminated plate that can improve the storage stability of a prepreg without extending the molding time.

[0004]

According to a first aspect of the present invention, there is provided a laminated plate produced by laminating a plurality of prepregs impregnated with a varnish containing an epoxy resin on a base material and heat-curing the prepregs. In the manufacturing method of 1, the epoxy resin and the curing agent are contained, and the content ratio of the curing accelerator is the epoxy resin 1
The first prepreg (A) impregnated with varnish of less than 0.05 parts by weight relative to 00 parts by weight, the epoxy resin and the curing accelerator are contained, and the content ratio of the curing agent is the epoxy resin 10.
The second prepreg (B) impregnated with varnish of less than 1.0 part by weight relative to 0 part by weight is alternately combined and laminated.

According to a second aspect of the present invention, there is provided a method for producing a laminated plate according to the first aspect, wherein the curing agent contained in the first prepreg (A) is dicyandiamide.
It is characterized in that the curing accelerator contained in the second prepreg (B) is an imidazole curing accelerator.

According to a third aspect of the present invention, there is provided a method for producing a laminated plate according to the first aspect, wherein the curing agent contained in the first prepreg (A) is a polyfunctional phenolic curing agent. The curing accelerator contained in the prepreg (B) is an imidazole curing accelerator.

According to a fourth aspect of the present invention, there is provided the method for producing a laminated plate according to the first aspect, wherein the curing agent contained in the first prepreg (A) is a polyfunctional phenolic curing agent. The curing accelerator contained in the prepreg (B) is a phosphorus-based curing accelerator.

[0008]

Embodiments of the present invention will be described below.

The substrate in the present invention includes, for example, glass cloth, glass paper, paper and the like, and is not particularly limited as long as it is a substrate generally used for laminated plates.

The epoxy resin in the present invention may be a compound having two or more epoxy groups in the molecule, and may be a mixture of two or more epoxy resins.
Specific examples include bisphenol A type epoxy resin and novolac type epoxy resin.

As the curing agent in the present invention, a compound having two or more functional groups capable of reacting with an epoxy group in the molecule may be used, and amine-based compounds, acid anhydride-based compounds, polyfunctional phenol-based compounds, and the like can be used, with particular limitations. However, from the viewpoint of improving the storage stability of the prepreg, a multifunctional phenolic curing agent, which is a curing agent having extremely low reactivity in the absence of a latent curing agent, dicyandiamide, or a curing accelerator, is used. Preference is given to using.

As the curing accelerator in the present invention, for example, an imidazole type, a tertiary amine type, a phosphorus type or the like can be used, and there is no particular limitation. Then, depending on the types of the epoxy resin and the curing agent used, a curing accelerator capable of accelerating these reactions may be selected.

In the present invention, without extending the molding time,
A first prepreg impregnated with a varnish, which contains an epoxy resin and a curing agent, and has a curing accelerator content of less than 0.05 parts by weight per 100 parts by weight of the epoxy resin in order to improve the storage stability of the prepreg. A second prepreg (B) impregnated with a varnish containing (A), an epoxy resin and a curing accelerator, and the content ratio of the curing agent is less than 1.0 part by weight relative to 100 parts by weight of the epoxy resin is alternately combined. And stack. As described above, the first prepreg (A) does not contain the curing accelerator, or the curing accelerator is contained in a very small amount, and the second prepreg (B) does not contain the curing agent or does not contain the curing accelerator. Even if it is extremely small, each prepreg alone has good storage stability, and the amount of the curing accelerator contained in the second prepreg (B) can be arbitrarily increased, so that the molding time is extended. There is no need, and the molding time can be shortened depending on the amount of the curing accelerator.

When the curing agent contained in the first prepreg (A) is dicyandiamide, the curing accelerator contained in the second prepreg (B) is an imidazole type curing accelerator. It is preferable from the viewpoint of accelerating the reaction between the resin and the curing agent. As this imidazole-based curing accelerator, 2-methylimidazole, 2-ethyl-
Examples thereof include imidazoles such as 4-methylimidazole and 2-phenylimidazole. The content of the imidazole-based curing accelerator contained in the second prepreg (B) may be determined according to the desired length of molding time and the characteristics of the laminate, but is 4.0 with respect to 100 parts by weight of the epoxy resin. If the amount is more than 4.0 parts by weight, the reaction of the epoxy resin with the imidazole-based curing accelerator may proceed and the storage stability of the second prepreg (B) may be impaired. Therefore, the amount is preferably 4.0 parts by weight or less.

When the curing agent contained in the first prepreg (A) is a polyfunctional phenol type curing agent such as a phenol novolac resin or an alkylphenol novolac resin, curing acceleration contained in the second prepreg (B) is promoted. The agent is preferably an imidazole-based curing accelerator or a phosphorus-based curing accelerator from the viewpoint of promoting the reaction between the epoxy resin and the curing agent. Examples of the imidazole-based curing accelerator include 2-methylimidazole and 2
Examples include imidazoles such as -ethyl-4-methylimidazole and 2-phenylimidazole, and examples of phosphorus-based curing accelerators include tertiary phosphines such as triethylphosphine, tributylphosphine, and triphenylphosphine. The content of the imidazole-based curing accelerator contained in the second prepreg (B) in this case may be determined according to the desired length of molding time and the characteristics of the laminated plate, and is based on 100 parts by weight of the epoxy resin. 4.
If the amount exceeds 0 parts by weight, the reaction of the epoxy resin with the imidazole-based curing accelerator proceeds and the second prepreg (B)
Therefore, the amount is preferably 4.0 parts by weight or less because it may impair the storage stability. Also, the second prepreg (B)
The content of the phosphorus-based curing accelerator contained in the composition may be determined according to the desired length of molding time and the characteristics of the laminated plate. However, since uneven curing may occur, it is preferably 15 parts by weight or less.

In the present invention, the first prepreg (A) and the second prepreg (B) are alternately combined and laminated as described above. When the total number of prepregs to be laminated is an even number, they may be simply combined alternately. However, when the total number of prepregs to be laminated is an odd number of 3 or more, one of the prepregs is increased by one. The layers are combined alternately.

[0017]

EXAMPLES In the following examples and comparative examples, the following raw materials were used in the proportions shown in Tables 1 to 3.

Epoxy resin 1 --- epoxy equivalent 500
Brominated bisphenol A type epoxy resin (manufactured by Dow Chemical Co., product number DER511) Epoxy resin 2 --- epoxy equivalent 200 cresol novolac type epoxy resin (manufactured by Toto Kasei Co., product number YDC
N702P) Curing agent 1 --- dicyandiamide (reagent, molecular weight 84) Curing agent 2 --- Phenol novolac resin having a hydroxyl equivalent of 105 (manufactured by Arakawa Chemical Industry Co., Ltd., Tamanol 7)
52) Curing accelerator 1--2-ethyl-4-methylimidazole (reagent) Curing accelerator 2--triphenylphosphine (reagent)

Raw materials and organic solvents in the proportions shown in Tables 1 to 3 were blended to prepare varnishes in Examples and Comparative Examples. The obtained varnish was impregnated into a glass cloth (manufactured by Asahi Schwebel, product number 7628W) and then dried in a dryer at 150 ° C for about 7 minutes to obtain a prepreg having a resin content of 45% by weight and a thickness of 0.2 mm. It was made. In addition,
In each example, the first prepreg (A) and the second prepreg (B) described in the section of the above-described embodiment were produced,
In each comparative example, only one type of prepreg was manufactured. The storage stability of each of the obtained prepregs was evaluated by the method shown below, and the results are shown in Tables 1 to 3.

(Evaluation method of storage stability of prepreg) The prepreg is stored in a constant temperature bath at 40 ° C, and the minimum melt viscosity of the resin component of the prepreg at 130 ° C is measured at regular intervals. This minimum melt viscosity was measured by rubbing off the resin component adhering to the prepreg and using a Koka type flow tester. From the obtained results, based on the following formula,
The rate of change in melt viscosity is calculated. The number of days of storage in which the rate of change in melt viscosity exceeds 50% is defined as "the number of days of storage of the prepreg at 40 ° C". Then, the prepreg is evaluated using this number of days as a characteristic value indicating the storage stability of the prepreg.

Melt viscosity change rate (%) = (minimum melt viscosity after aging−initial minimum melt viscosity) × 100 / (initial minimum melt viscosity) Then, in each example, the first prepreg (A) was used. And the second
The prepregs (B) of (1) were alternately combined one by one, and a total of four prepregs were laminated. Further, in each comparative example, four prepregs of the same type were laminated. 170 degreeC of the obtained laminated body
The heat-pressurization molding was performed while changing the molding time to obtain a laminate, and the curing reaction completion time was evaluated by the following method using the obtained laminate, and the results are shown in Tables 1 to 3. . Further, with respect to the laminated plate obtained by setting the molding time as the completion time of the curing reaction, it was visually observed whether there was any abnormality such as coloring or unevenness of curing, and the results are shown in Tables 1 to 3.

(Evaluation Method of Curing Reaction Completion Time) The coefficient of thermal expansion of each laminate obtained by changing the molding time was measured by a coefficient of thermal expansion measuring device (TMA device), and the inflection point of the coefficient of thermal expansion was found. Find the resulting temperature. The temperature at which the inflection point of this coefficient of thermal expansion occurs is defined as the glass transition temperature (Tg) of the laminated plate, and the glass transition temperature (Tg) fluctuates less than 5 ° C even if the molding time is changed. The curing reaction completion time is set.

[0023]

[Table 1]

[0024]

[Table 2]

[0025]

[Table 3]

As can be seen from Tables 1 to 3, the examples of the present invention have the same or shorter curing reaction completion time and longer storable days of prepreg than the comparative examples. Then, it was confirmed that it is possible to shorten the curing reaction completion time by increasing the amount of the curing accelerator contained in the second prepreg (B) (Examples 2, 4, and 6). .

[0027]

EFFECTS OF THE INVENTION According to the method for manufacturing a laminated plate of the invention according to claims 1 to 4, since the storage stability of the prepreg can be improved without extending the molding time, the laminated plate is manufactured. Very useful when doing.

Front page continued (72) Inventor Eiji Motobu 1048 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Works Co., Ltd.

Claims (4)

[Claims] 1. A method for producing a laminated plate, comprising manufacturing a plurality of prepregs in which a base material is impregnated with a varnish containing an epoxy resin and heating and curing the prepreg, the epoxy resin and the curing agent are contained, and a curing accelerator is contained. Ratio is 100 epoxy resin
A first prepreg (A) impregnated with a varnish of less than 0.05 parts by weight based on parts by weight, an epoxy resin and a curing accelerator are contained, and the content ratio of the curing agent is 1.0 with respect to 100 parts by weight of the epoxy resin. A method for producing a laminated plate, characterized in that the second prepreg (B) impregnated with a varnish of less than part by weight is alternately combined and laminated. 2. The curing agent contained in the first prepreg (A) is dicyandiamide, and the second prepreg (B).
The method for producing a laminated board according to claim 1, wherein the curing accelerator contained in is an imidazole curing accelerator. 3. A curing agent contained in the first prepreg (A) is a polyfunctional phenol type curing agent, and a curing accelerator contained in the second prepreg (B) is an imidazole type curing accelerator. The method for manufacturing a laminated board according to claim 1, which is characterized in that. 4. The curing agent contained in the first prepreg (A) is a polyfunctional phenol type curing agent, and the curing accelerator contained in the second prepreg (B) is a phosphorus type curing accelerator. The method for manufacturing a laminated board according to claim 1, which is characterized in that.