JPH08104737A - Epoxy resin composition and prepreg prepared using the same - Google Patents

Abstract

PURPOSE: To obtain an epoxy resin compsn. which enables the production of a fast-curing, voidless prepreg having a high storage stability and a substrate improved in heat resistance by the hot-melt process using specific components. CONSTITUTION: The compsn. is obtd. by compounding 100 pts.wt. epoxy resin component comprising 3-50 pts.wt. polyepoxy resin, a brominated epoxy resin in such an amt. as to make the bromine content of the epoxy resin component to be 15-30wt.%, and a diepoxy resin with 1.0-4.0 pts.wt. dicyandiamide and an imidazole compd. latent at normal temp. and in an amt. of 3-95mol% based on dicyandiamide. A fibrous sheetlike reinforcing substrate is directly coated with the compsn. at 50-90 deg.C and impregnated therewith by heating, thus providing a prepreg having a viscosity at 100 deg.C of 1,000-1,000,000cP. The prepreg is semicured by further heating at 100 deg.C, thereby providing the prepreg having a viscosity at 100 deg.C of 100,000-10,000,000cP.

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 useful for producing printed wiring boards and the like, and a prepreg using the same. More specifically, the present invention relates to an epoxy resin composition and a prepreg that enable rapid curing with good storage stability and production of voidless prepreg by a hot melt method, and that provides a high-performance printed board with improved heat resistance.

[0002]

2. Description of the Related Art Epoxy resin is the heat resistance of the cured product,
It is excellent in elastic modulus, hardness, chemical resistance and the like, and is widely used as a resin composition for prepreg, which uses reinforcing fibers such as glass fiber, aramid fiber and carbon fiber. Such a prepreg (hereinafter sometimes referred to as PP) is widely used in various technical fields, and in particular, PP using glass fiber is one of the important applications of which is the production of printed circuit boards. . In recent years, with the miniaturization of electronic devices in recent years, the density and integration of printed circuit boards have increased, and the demand for improved heat resistance of printed circuit boards has increased.

Conventionally, prepregs are manufactured according to their manufacturing method.
Solvent type that uses a low viscosity impregnating solution (epoxy resin varnish) that uses a solvent as the resin composition for prepreg, and hot melt that uses a high viscosity resin that fluidizes at a certain temperature without using a solvent. There are a mold type and a room temperature impregnated type that uses a low-viscosity resin that is fluid at room temperature without using a solvent.

Solvent type PP has been used for molding the above-mentioned printed circuit board. However, solvent type P
In P, the epoxy resin composition is varnished by using various solvents to reduce the viscosity and the process of impregnating the base glass fiber with the resin is performed, so that the blending of the curing agent is limited for stable production. , PP rapid curing and substrate molding efficiency improvement cannot be realized. Furthermore, the storage stability of PP is poor,
In addition, since a large amount of voids due to the solvent remain in the PP, there is a problem in heat resistance performance and stable manufacturing of the final printed circuit board. Therefore, quick curing of the resin, improvement of impregnation into the base glass cloth, removal of voids in PP, P
In order to improve the stability of P and the heat resistance of the substrate,
Mixtures of bisphenol A type epoxy resin, brominated bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol A type novolac epoxy, bisphenol A type novolac (Japanese Patent Laid-Open No. 64-175).
6, JP-A-4-66890) and an epoxy resin having a limited amount of α-diol and hydrolyzable chlorine (Japanese Patent Publication No.
No. 44574), polyglycidyl ether, bisphenol A type epoxy resin, bisphenol F type epoxy resin, tetrabromobisphenol A type epoxy resin, bisphenol compound and the like mixture (JP-A-5-1).
No. 78963), a grafted resin of a brominated phenol novolac type epoxy resin and a bisphenol A type epoxy resin (JP-A-4-272919), and blending dicyandiamide and an imidazole compound. Is proposed. However, even if such an epoxy resin composition is used, it is difficult to completely solve the above problems when PP is produced by the solvent method.

[0005]

In the case of the solvent type PP, the resin composition is dissolved in a solvent to reduce the viscosity and the glass fiber is impregnated with the resin composition. Then, it is semi-cured while applying heat to remove the solvent, and the final product is manufactured. In the case of the solvent type, since the solvent is used as described above, the stability of the resin is poor, and problems are likely to occur in the stable production of PP and the stable molding of the printed circuit board. Further, in order to obtain the above stability,
In general, the amount of the curing agent or the curing accelerator has to be considerably reduced, and therefore the PP cannot achieve the rapid curing / improvement of the molding cycle. Furthermore, in the case of the same PP, since the process of semi-curing is performed while removing the solvent by heat, the product PP
A considerably large amount of voids remain inside, which adversely affects the molding of the printed circuit board and the performance of the molded board, particularly the heat resistance. For example, even if the linear velocity in the desolvent process is reduced and the reduction of residual voids is aimed at, the production efficiency is only significantly reduced, and it is difficult to significantly reduce the voids (generally 4,000 to 5). 1,000 / in ²
Exist to some extent). Furthermore, by using a solvent,
There are drawbacks such as environmental problems and large capital investment for solvent recovery equipment.

Therefore, an object of the present invention is to provide an epoxy resin composition and a prepreg using the same which can solve the above problems and further improve the heat resistance of the final product.

[0007]

According to the present invention, 3 to 5
1 part by weight of a polyfunctional epoxy resin, a brominated epoxy resin in an amount such that the bromine content is 15 to 30% by weight based on the total amount of the epoxy resin, and a bifunctional epoxy resin 1
To 100 parts by weight of epoxy resin, dicyandiamide 1.0
~ 4.0 parts by weight and 3 to 95 relative to the dicyandiamide
There is provided an epoxy resin composition comprising a mol% of a latent imidazole compound at room temperature.

Further, according to the present invention, the above-mentioned substantially solvent-free epoxy resin composition is directly coated on a sheet-like reinforcing substrate made of fibers at 50 to 90 ° C., and then impregnated by heating. And the viscosity of the matrix resin composition at 50 ° C. is 1,000 to 1.0.
An epoxy resin prepreg having a capacity of 0,000 cps is provided, and the above-mentioned substantially solvent-free epoxy resin composition is directly coated on a sheet-like reinforcing substrate made of fiber at 50 to 90 ° C. Then
Then, after heat impregnation, it is further heated and semi-cured,
Moreover, the epoxy resin prepreg is provided in which the matrix resin composition has a viscosity at 100 ° C. of 100,000 to 10,000,000 cps.

As a result of intensive studies by the present inventors, as described above, the storage stability of the resin and the PP production stability are improved, the curing rate of the resin and the molding efficiency are greatly increased, and further voids in the PP are eliminated. In order to drastically reduce, simplify and streamline the substrate molding process, and greatly improve the heat resistance of the product substrate,
We have found that: That is, in order to realize the storage stability of the resin and to manufacture PP without voids, by selecting a curing agent and a curing accelerator which are substantially free of a solvent and are stable at room temperature and have potential. Will be realized. Further, in order to improve the heat resistance, which is the most important property of the product substrate, it is essential to remove the voids described above, and also to introduce a thermally stable and highly rigid aromatic structure, improve the crosslink density, and Has been found to require elimination of the heteroatoms that are the origin of thermal decomposition. Among them, the control of the matrix structure is achieved by, for example, selecting the polyfunctional epoxy resin species and controlling the amount thereof. Further, regarding the elimination of heteroatoms, it has been found that it is possible to significantly improve the heat resistance while realizing the stability and fast curing characteristics of the resin by controlling the quality and amount of the curing agent that is the nitrogen source. It was According to it, it is essential that the addition amount of dicyandiamide which is a curing agent is 1.0 to 4.0 parts by weight, and the latent imidazole which is an accelerator is 3 to 95 mol% with respect to dicyandiamide. Only when the above condition was satisfied, a highly heat-resistant resin having excellent storage stability, containing almost no voids, and capable of improving molding efficiency by rapid curing was achieved.

The present invention will be described in detail below. The epoxy resin (main component) used in the epoxy resin composition of the present invention is
3 to 50 parts by weight of a polyfunctional epoxy resin, brominated epoxy resin and bifunctional epoxy resin in an amount such that the bromine content is 15 to 30% by weight based on the total amount of the epoxy resin, and 100 parts by weight in total. . Polyfunctional epoxy resins include orthocresol novolac type, phenol novolac type, glycidyl amine type, etc. which are on the market such as Yuka Shell Co., Sumitomo Chemical Co., Asahi Kasei Co., Ltd., Dainippon Ink Co., Ltd. It is a resin that has more functional groups than the functional group, and the epoxy equivalent of the novolac type is 170-25
0, epoxy equivalent 90-150 for glycidyl amine type
Is. The chlorine concentration of the resin is also important, and the hydrolyzable chlorine content is 800 ppm, preferably 500 ppm or less. (If this is high, the reaction rate becomes slow and the heat resistance decreases). By incorporating 3 to 50 parts by weight of a polyfunctional epoxy resin per 100 parts by weight of the base resin, heat resistance and Tg can be improved. When the amount of the polyfunctional epoxy resin is more than 50 parts by weight, the number of epoxy groups in the system becomes too large and steric hindrance of the epoxy groups causes a slight curing failure. Further, in this case, the viscosity of the system is too high, which makes it difficult to form PP.

Specific examples of the above polyfunctional epoxy resin include the following. Phenol novolac type: Yuka Shell Co., Ltd .: Epicoat 152 (2.2 functional),
Epicoat 154 (3.5 functional +), Dainippon Ink Co., Ltd .: Epicron N730 (2.5 functional), Epicron N740 (3.6 functional), Epiclon N738-740 (3.5-4.5 functional), Nippon Kayaku Co., Ltd .: EPPN201, RE300, etc. Cresol novolac type: Yuka Shell Co., Ltd .: Epicoat 180 series, Asahi Kasei Corporation: A. R. E273, 280, 299, Sumitomo Chemical Co., Ltd .: ESCN-195X, 220, Dainippon Ink Co., Ltd .: Epicron N-665, 670,
673, 680, 690, 695, Nippon Kayaku Co., Ltd .: ECON-100, 102S, 103
S, 104S, etc. Glycidylamine type: Yuka Shell Co., Ltd .: Epikote 604 [tetraglycidyldiaminodiphenylmethane (TGDDM)], Sumitomo Chemical Co., Ltd .: ELM-100 (trifunctional), ELM-
120 (3-functional), ELM-434 (4-functional), Dainippon Ink Co., Ltd .: Epiclon 421L (3-functional),
430 (tetrafunctional). Other glycidyl amine type: triglycidyl-p-aminophenol (trifunctional) [Chipa Geigy Co., Ltd., Toto Kasei Co., Ltd.] tetraglycidyl-m-xylylenediamine (tetrafunctional)
[Mitsubishi Gas Chemical Co., Ltd.] Triglycidyl-metaaminophenol (trifunctional) [Sumitomo Chemical Co., Ltd.].

Further, in the present invention, the base resin 100
It is preferable to add the brominated epoxy resin in an amount such that the bromine content is 15 to 30% by weight (more preferably 17 to 25% by weight) per part by weight. In the brominated epoxy resin, a type in which a part of the aromatic ring hydrogen of the bisphenol A type epoxy resin is replaced by bromine is general, and a high brominated type (bromine content 45 to 55% by weight) and a low bromine content are used. There are chemical types (bromine content 10 to 30% by weight). Bromine content is 15% by weight based on 100 parts by weight of resin
If less, UL (Underwriter
In the combustion test according to the Laboratories standard, the first framing becomes 10 seconds or more, and the V-0 standard of UL94 safety standard regarding flame retardancy cannot be achieved. Further, when the bromine content exceeds 30% by weight, heat resistance is deteriorated, which is not preferable.

Specific examples of the above-mentioned brominated epoxy resin include the following. Highly brominated type: Yuka Shell Co., Ltd .: Epikote 5050T60, 505
0,5051, Ciba Geigy, Inc .: Araldite XAC8100,8
049SP, XAC8101, Sumitomo Chemical Co., Ltd .: ESB340, ESB400, Dainippon Ink Co., Ltd .: Epicron 152, Toto Kasei Co., Ltd .: Epomate YDB340, YDB40
0, Mitsui Petrochemical Co., Ltd .: EPOMIK R210, R21
First magnitude. Low brominated type: Yuka Shell Co., Ltd .: Epikote 5045B80, 504
6B80, 5048B70, 5049B70, Ciba Geigy Ltd .: Araldite XAC5010, 8
011LA, 8024LA, Sumitomo Chemical Co., Ltd .: ESB500, ESB700, Dainippon Ink Co., Ltd .: Epicron 1120, Toto Kasei Co., Ltd .: Epomate YDB500, YDB70
0 etc.

Further, in the present invention, a bifunctional epoxy resin is used for the remainder [100- (polyfunctional epoxy resin + brominated epoxy resin)] of the main resin. Bifunctional epoxy resins include bisphenol A type (diglycidyl ether, diglycidyl ester type, etc.) marketed by Yuka Shell Co., Sumitomo Chemical Co., Asahi Kasei Co., Ltd., Dainippon Ink Co., Ltd., etc. ) Resin. The following are mentioned as a specific example of these bifunctional epoxy resins. Yuka Shell Co., Ltd .: Epicoat 801, 802, 80
7, 815, 819, 828, 834, 1001, 10
02, 1003, 1004, etc., Dainippon Ink Co., Ltd .: Epicron 840, 850, 85
5, 860, 900, 830, etc. Sumitomo Chemical Co., Ltd .: ELA115, 127, 128, 13
4th grade, Asahi Kasei Corporation: AER330, 331, 354, 33
7, 661, 662, etc., Nippon Kayaku Co., Ltd .: RE-403S, -404S, -41.
0S, -310S, -304S, etc.

In the epoxy resin composition of the present invention,
Dicyandiamide (Dicy) of 1.0 to 4.0 parts by weight (preferably 1.5 to 3.0 parts by weight) is blended with 100 parts by weight of the base resin as a curing agent. Since Dicy is a latent curing agent, the resin has good storage stability. If the amount of Dicy is less than 1.0 part by weight, curing will be insufficient, and if it exceeds 4 parts by weight, heat resistance will decrease.

In the present invention, an imidazole compound having a latent property at room temperature is added as a curing accelerator. The blending amount is 3 to 95 mol% (molar ratio) with respect to Dicy, and preferably 9 to 70 mol% with respect to Dicy. Imidazole compound is 3 mol% based on Dicy
If it is less than 95% by weight, rapid curing cannot be achieved.
If it exceeds, the storage stability of PP deteriorates and the heat resistance also decreases.

As the imidazole compound, generally used 2-methylimidazole, 2-ethyl-4methylimidazole and the like are dissolved in the epoxy resin even when mixed at room temperature to start the reaction, so that storage stability and PP are improved. Is not preferable because of poor production stability. On the other hand, for example, an imidazole compound having an aliphatic side chain or a phenyl group at the 2-position is a solid at room temperature and does not dissolve in an epoxy resin, but dissolves / starts a reaction at a high temperature. That is, the storage stability and the production stability of the resin can be obtained because it is a latent curing accelerator at room temperature. Thus, it is characterized by adding an imidazole compound that does not dissolve in the epoxy resin at room temperature, for example, 2-undecylimidazole [C11Z manufactured by Shikoku Chemicals Co., Ltd.], 2-heptadecylimidazole [Shikoku Chemicals (stock) ) C17Z], 2-phenylimidazole [2PZ manufactured by Shikoku Kasei Co., Ltd.], and microcapsule-type imidazole low-temperature curing agents described in JP-A No. 64-70523.

The composition of the present invention containing the latent imidazole compound at room temperature has a viscosity increase within 3 times the initial value after 7 days at room temperature (23 ° C.), which indicates storage stability of the resin and prepreg. Good manufacturing stability.

As the reinforcing fiber used in the prepreg of the present invention, an organic fiber such as glass fiber or aramid fiber is used from the viewpoint of electric insulation and strength of the printed circuit board, and the fiber is added to the epoxy resin composition. 20 in content
~ 70 wt% used.

Further, in the epoxy resin composition for prepreg of the present invention, various additives such as a filler, a coloring agent and a diluent may be blended within the range not impairing the basic characteristics.

In order to produce the prepreg of the present invention, for example, first, the above resin composition containing no solvent is directly applied to a sheet-like reinforcing substrate made of fibers at 50 to 90 ° C. using a coater device. To coat. Next, the prepreg is manufactured by impregnating the reinforcing fibers with the resin through a heating bath. In the above process, heat rolls and heat plates may be installed before and after the heating impregnation tank to smooth the prepreg.

At this time, the viscosity of the matrix resin of the prepreg is 1,000 to 1,000,0 at 50 ° C.
00 cps, preferably 50,000-500,
000 cps. The amount of voids in the obtained prepreg is preferably 200 / in ² or less,
It is more preferably 80 / in ² or less. Since the prepreg of the present invention uses no solvent at all, the amount of voids can be significantly reduced as compared with the solvent system, and the heat resistance of the molded substrate is improved.

Further, the temperature of the impregnated heater and the prepreg residence time are optimized, or a new heating zone is provided at the rear of the impregnated heater to semi-cure (B stage).
It is also possible to produce a prepreg by carrying out. When the semi-curing step is included, the viscosity of the matrix resin composition of the prepreg is 100,0 at 100 ° C.
It is from 00 to 10,000,000 cps, preferably from 200,000 to 5,000,000 cps.

[0024]

EXAMPLES Next, the present invention will be described in more detail by way of examples. All parts shown below are based on weight.

Example 1 <Resin Blend> A resin composition having the blend ratio shown in Table 3 was prepared using the following resins. Resin composition Epicoat 828 30 parts (Oilized shell: glycidyl ether type, epoxy equivalent 180) Epicoat 1001 20 parts (Oilized shell: glycidyl ether type, epoxy equivalent 450) Epicoat 5050 40 parts (Oilized shell: glycidyl ether type, epoxy Equivalent 400, bromine content 50% by weight) Epicoat 180S70 10 parts (oiled shell: cresol novolak type, epoxy equivalent 213) Dicy (dicyandiamide) 1.5 parts (oiled shell: Dicy, average particle size 7 μm) C17Z [ 2-heptadecyl imidazole, manufactured by Shikoku Kasei Co., Ltd.] 1.0 part (18 mol% with respect to Dicy) Viscosity of resin composition at 50 ° C Immediately after production: 274,000 cps One month later: 283,000 cps (23 ° C) Save)

<Production of prepreg (hot melt method)
> The epoxy resin composition having the above composition was coated on a reinforcing fiber [glass cloth fiber {Kanbo Co., Ltd., KS1633}, fiber basis weight 215 g / m ² ] using a coater (resin coating device) to give a resin content of 42%. Direct coating was performed at 70 ° C. so that the ratio became constant, and then heat impregnation was performed at 130 ° C. for 30 seconds to obtain a prepreg. 150 ° C-
It was heated under the condition of 2 minutes and converted into B stage to obtain a prepreg with a reaction rate of 53%.

<Storage stability of resin> Resin composition and B
In order to confirm the stability of the staged PP resin, the viscosity of the resin at 50 ° C. and the value of the reaction rate by DSC were measured. The results are shown in Tables 1 and 2.

[Table 1]

[Table 2]

<Curing characteristics> 15 using a gelling tester
The gelation time at 0 ° C. was examined and used as an index of the curing rate. Gelation time of B-stage resin: 52 seconds

<Manufacture of Substrate> 8 plies of the obtained prepreg were laminated, and copper foil (Nikko Gould standard 35 μm thick) was attached to each of the front and back surfaces of the prepreg, and a hot press machine was used for 15
It was cured and molded at 0 ° C. for 30 minutes to obtain a 1.6 mm thick GFRP substrate with copper foil.

<Measurement of Physical Properties> Table 4 shows various properties of the obtained prepreg and substrate. The measurement conditions for various performances are as follows. Peel strength, solder heat resistance: In accordance with JIS C6481. Regarding the solder heat resistance, GFRP with copper foil was floated on a solder bath at 260 ° C., and the time until blistering occurred on the copper foil was measured. Flame resistance: Complies with UL94 safety standards. Gelation time: A gelation tester was used to measure the gelation time at 150 ° C. (the time for the resin to cure into a rubber). It was used as an index of the curing speed. Curing reaction rate of resin: The calorific value of the resin before and after the B-stage conversion was measured by DSC and used as the curing reaction rate of the B-stage conversion resin. DSC measurement condition: 30 ° C. → 250 ° C. (10
° C / min) Quantification of voids in PP: The presence or absence of voids was examined by observing the obtained PP with an optical microscope (transmission). At this time, the number of voids in an area of 1 inch square was counted at 10 or more places, and the average value was defined as the PP void density.

Examples 2 to 7 An epoxy resin composition was prepared in the same manner as in Example 1 except that the composition of Dicy and C17Z was changed as shown in Table 3, and the epoxy resin composition was prepared using the same and the production of PP and the substrate. Was manufactured and evaluated. The results are shown in Table 4.

Examples 8 to 10 Epoxy resin compositions were prepared in the same manner as in Example 1 except that Dicy = C17Z = 1.5 parts was fixed and the composition of the main component was changed as shown in Table 3. , Using it PP
And the substrate were manufactured and evaluated. The results are shown in Table 4.

Examples 11-14 Except that the accelerator was changed from C17Z to a microcapsule type imidazole curing agent HX3722 (manufactured by Asahi Kasei Co., Ltd.), and the composition of the main agent was partially changed as shown in Table 3, An epoxy resin composition was prepared in the same manner as in Example 1, and PP and a substrate were produced using the same.
evaluated.

Comparative Example 1 An epoxy resin composition was prepared in the same manner as in Example 9 except that the polyfunctional epoxy resin 180S70 was added in an amount of 70 parts and no bifunctional epoxy resin was added as shown in Table 5. Was prepared and PP was produced using it, but the resin viscosity was high and PP could not be stably produced.

Comparative Examples 2 to 3 Addition amount of the brominated epoxy resin 5050 was added so that the bromine content in the main component was 10% by weight and 35% by weight, respectively (addition amount of 5050, 20, 70 parts by weight, respectively). ), And an epoxy resin composition was prepared in the same manner as in Example 9 except that the compounding amounts of the bifunctional and polyfunctional epoxy resins were changed as shown in Table 5, and using the epoxy resin composition, the production of PP and the substrate were performed. Was manufactured and evaluated. Table 6 shows the results.

Comparative Examples 4 to 5 The addition amount of Dicy to 100 parts of the main agent was adjusted to 0.
5 parts and 6.0 parts, and except that the addition amount of C17Z was changed as shown in Table 5, an epoxy resin composition was prepared in the same manner as in Example 1, and it was used to produce PP and The substrate was manufactured and evaluated. Table 6 shows the results.

Comparative Examples 6 to 7 Epoxy resin compositions were prepared in the same manner as in Example 5 except that the amounts of imidazole C17Z added were 2.7 mol% and 110 mol% with respect to Dicy, respectively. Was used for the production of PP and the production of a substrate for evaluation. Table 6 shows the results.

Comparative Examples 8 to 9 Solvent-type epoxy resin compositions (epoxy resin varnish) were prepared by adding 50 parts of methyl ethyl ketone to 100 parts of each of the epoxy resin compositions having the same compositions as in Examples 2 and 12. Prepared. Attempts were made to produce PP and substrates using these epoxy resin varnishes. When glass cloth was coated with resin at 70 ° C., a curing reaction started and a rapid increase in viscosity occurred, resulting in a stable and uniform thickness. (Resin amount) PP could not be manufactured. A substrate was manufactured using a small amount of the manufactured PP and evaluated. Table 6 shows the results. The number of voids in the obtained PP was considerably large at 4532 and 6240 / in ² , respectively, and the resin areal unit weight was also unstable. Therefore, many bubbles were recognized in the obtained substrate. As a result, the substrate has low heat resistance.

[0039]

[Table 3]

[0040]

[Table 4]

[0041]

[Table 5]

[0042]

[Table 6]

[0043]

The epoxy resin composition for prepreg of the present invention comprises 3 to 50 parts by weight of a polyfunctional epoxy resin and bromine in an amount such that the bromine content is 15 to 30% by weight based on the total amount of the epoxy resin. 100 parts by weight of a epoxidized resin and a bifunctional epoxy resin, and 1.0 to 4.0 parts by weight of dicyandiamide and a latent imidazole compound at room temperature of 3 to 95 mol% based on the dicyandiamide. In addition, since the above-mentioned epoxy resin composition containing substantially no solvent is directly coated and impregnated on the sheet-shaped reinforcing base material made of fiber at 50 to 90 ° C., Moreover, the viscosity of the matrix resin composition at 50 ° C. is 1,000 to 1,000.
The above-mentioned substantially solvent-free epoxy resin composition was directly coated on a sheet-like reinforcing base material having a rate of 10,000 cps or made of fibers at 50 to 90 ° C., and then heat impregnated. After that, it is heated and semi-cured, and the matrix resin composition has a temperature of 100 ° C.
Viscosity at 100,000 to 10,000,000
Since it is assumed to be cps, it has the following excellent effects. The storage stability of the resin and the stability during prepreg production are good, and the performance of the final product, the molding substrate, is stabilized. It is environmentally clean without the step of removing the solvent, and there are almost no voids in the manufactured PP. This improves the performance of the molded substrate. The curing speed is considerably faster than that of the conventional solvent method, and it is possible to lower the molding temperature and increase the molding cycle. Improves solder heat resistance while achieving flame resistance (UL94V-0). The conventional FR-4 standard (NEMA, American Electrical Manufacturers' Association) is 1 minute (@ 260 ° C. solder bath), while it can be held for 10 to 20 minutes.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Makiharu Miyao 1-3-1, Nishitsurugaoka, Oi-cho, Iruma-gun, Saitama Tonen Research Institute

Claims (3)

[Claims] 1. A polyfunctional epoxy resin of 3 to 50 parts by weight,
1.0 to 4.0 parts by weight of dicyandiamide is added to 100 parts by weight of a brominated epoxy resin and a bifunctional epoxy resin such that the bromine content is 15 to 30% by weight based on the total amount of the epoxy resin. An epoxy resin composition, characterized in that a latent imidazole compound is mixed at 3 to 95 mol% with respect to dicyandiamide at room temperature. 2. A sheet-like reinforcing base material made of fibers is directly coated with the substantially solvent-free epoxy resin composition according to claim 1 at 50 to 90 ° C., and then heat impregnated. The viscosity of the matrix resin composition at 50 ° C. is 1,000 to 1,000,000.
Epoxy resin prepreg characterized by being cps. 3. A sheet-like reinforcing base material made of fibers is directly coated with the substantially solvent-free epoxy resin composition according to claim 1 at 50 to 90 ° C., followed by heat impregnation and heating. It is semi-cured, and the viscosity of the matrix resin composition at 100 ° C. is 100,
Epoxy resin prepreg characterized in that it is 000-10,000,000 cps.