JP4301008B2 - Prepreg and laminate manufacturing method - Google Patents

Description

  The present invention relates to a method for producing a prepreg and a laminate without substantially using an organic solvent.

  Generally, a prepreg used for a printed circuit board is obtained by applying a varnish obtained by dissolving a resin component such as a thermosetting resin in an organic solvent to a fiber base material such as a glass cloth, and drying by heating. Conventionally, a large amount of an organic solvent has been used for such a resin varnish. This is because preparation of the resin varnish and subsequent handling are easy, and there is an advantage that application and impregnation to the substrate can be performed uniformly. However, organic solvents evaporate in the drying process at the time of prepreg production, and many of them are processed by a combustion device or released into the atmosphere as they are, which may contribute to global warming and air pollution. Came to be pointed out. For this reason, various attempts have been made to reduce the amount of organic solvent used in prepreg production, such as a water-dispersed resin solution (see, for example, Patent Document 1), but it becomes difficult to apply the resin to the substrate. There were problems in manufacturing and quality problems such as reduced impregnation into the substrate.

  Recently, there is a strong demand for flame retardancy and low thermal expansion coefficient that do not depend on halogen-containing compounds such as bromine and chlorine as laminate characteristics, but it causes cyanate resin and metal migration as a resin composition that satisfies this requirement. In order to reduce the generation of voids, low molecular weight (low softening point, low viscosity) epoxy resins with good impregnation properties have been studied. In a composition using such a resin, there are cases where the resin cannot be handled by a simple method such as a slurry in which the resin is pulverized and dispersed in water, or an emulsion in which the resin is liquefied and dispersed in water. It is a problem to be done.

  In addition to this, for example, a method of using a low melting point resin or a liquid resin, and applying this to a base material by heating and mixing with other components (hot melt method) has been performed. Since the curing progresses as the melting time becomes longer, each component must be melt-mixed and further applied to the substrate in a short time, and the uniformity of the mixed resin may be insufficient. In addition, there are many problems in continuous production because the resin is easily consolidated into a device due to a temperature drop during production or the thermosetting resin component is gelled by heating.

  In addition, a method of directly applying a powdery resin has been proposed, but when a powdery resin having a particle size of several tens to several hundreds of μm is used, it is difficult to uniformly mix and apply the materials, and the resin It may be partially cured or the impregnation of the substrate may be insufficient. On the other hand, when a powdery resin having a smaller particle size is used, the bulk density decreases and handling becomes difficult, and there is a problem that the finely divided material causes secondary aggregation and the uniform dispersibility is reduced. Neither method has been put to practical use.

  On the other hand, when a water-soluble resin such as a water-based paint is used, the substrate impregnation property can be almost the same as when an organic solvent is used. It is difficult to satisfy the required electrical and mechanical properties, and it is also necessary to select these raw materials from a very limited range of types, compared with the case of using an organic solvent. This is often expensive.

JP 09-316219 A

  The present invention provides a method for producing a prepreg capable of obtaining a laminate having performance equivalent to that when a conventional organic solvent is used without substantially using an organic solvent, and a method for producing a laminate using the same. It is to provide.

Said subject is achieved by the following this invention (1)-( 3 ).
(1) In the manufacturing method of the prepreg comprised from a fiber base material and the thermosetting resin composition carry | supported by the said fiber base material, a softening point is 100 degrees C or less, The at least 1 type has the softening point 40. Two or more thermosetting resins having a temperature of not more than 0 ° C. are melted and mixed by heating. After that, the molten resin composition is dispersed in water to form an aqueous emulsion resin liquid, and the resin liquid is supported on the fiber base material. A method for producing a prepreg characterized by the above.
(2) The method for producing a prepreg according to (1), wherein the thermosetting resin contains an epoxy resin and / or a cyanate resin.
(3) A method for producing a laminated board, wherein the prepreg obtained by the method for producing a prepreg according to (1) or (2) is heated and pressed.

  The method for producing a prepreg of the present invention is a method for producing a prepreg composed of a fiber base material and a thermosetting resin composition, using two or more kinds of thermosetting resins, and heating and melting and mixing them. Thereafter, the melted resin composition is dispersed in water to form an aqueous emulsion resin liquid, and the resin liquid is supported on the fiber base material. Thereby, a prepreg equivalent to the conventional one can be produced without substantially using an organic solvent.

  When the thermosetting resin has a softening point of 100 ° C. or lower, the resin can be easily melted and mixed and emulsified, and when at least one resin has a softening point of 40 ° C. or lower (including a liquid resin), Heat melting and mixing and emulsification of the resin are facilitated, and a prepreg in which the resin is sufficiently permeated between the monofilaments of the fiber substrate can be obtained. Therefore, it is more preferable that the thermosetting resin used in the present invention has a softening point of 100 ° C. or lower, and at least one of them has a softening point of 40 ° C. or lower.

The method for producing a laminate according to the present invention is characterized by heat-press molding the prepreg obtained by the above-described prepreg production method, and has excellent heat resistance without voids, equivalent to the conventional one. A laminated board can be obtained.
In addition, since the prepreg manufacturing method and the laminate manufacturing method of the present invention do not substantially use an organic solvent, resource saving, energy saving, and cost reduction can be achieved, and further, the working environment can be improved. It can also contribute to the reduction of air pollution.

Below, the manufacturing method of the prepreg of this invention is demonstrated.
In the present invention, the prepreg is composed of a fiber base material and a thermosetting resin composition supported on the fiber base material. This resin composition contains two or more kinds of thermosetting resins, and these resins are heated, melted and mixed, and dispersed in water, usually an aqueous emulsifier solution, to obtain an aqueous emulsion resin solution. In this step, usually, an aqueous emulsifier solution is gradually added to and mixed into the heat-melted resin composition to form an emulsion. Next, if necessary, an inorganic filler, a curing agent, a curing accelerator, and other additives are added to the aqueous emulsion resin liquid to form an impregnating resin liquid, which is supported on the fiber substrate by impregnation or the like. Thereby, since the prepreg equivalent to the conventional one can be produced without substantially using the organic solvent, the steps necessary for the removal and treatment of the organic solvent can be omitted.

The thermosetting resin composition used in the present invention will be described.
In the present invention, the thermosetting resin used is an epoxy resin, a cyanate resin, a phenol resin, or the like, and is not particularly limited. Examples of the epoxy resin include bisphenol type epoxy resins such as bisphenol A type and bisphenol F type, novolac type epoxy resins, biphenyl type epoxy resins and the like, and examples of cyanate resins include novolak type cyanate resins and prepolymers thereof. . Thereby, the flame resistance, the low linear expansion property, heat resistance, mechanical characteristics, and electrical characteristics which are basically required as a prepreg and a laminated board can be provided. In the present invention, two or more kinds of thermosetting resins are contained, and by melting and mixing them, the melt viscosity of the resin is lowered, and the subsequent emulsification becomes easy. Preferably, it contains an epoxy resin and a cyanate resin. Thereby, the characteristics can be further improved.

  The thermosetting resin preferably has a softening point of 100 ° C. or lower. Thus, after the resin is melted, an operation for emulsification can be easily performed by a usual method, and the obtained emulsion is stable, and the resin can be easily removed in the impregnation drying step. Can penetrate into. Moreover, it is preferable that at least one of the thermosetting resins has a softening point of 40 ° C. or less. This facilitates heat melting and mixing and emulsification of the resin, and in addition, the resin can sufficiently penetrate between the monofilaments of the fiber base material. Therefore, it is more preferable that the thermosetting resin used in the present invention has a softening point of 100 ° C. or lower, and at least one of them has a softening point of 40 ° C. or lower.

  In this invention, a hardening | curing agent and a hardening accelerator can be mix | blended with the said thermosetting resin. For example, when the thermosetting resin is an epoxy resin, an acid anhydride compound, an amine compound, an imidazole compound, a novolak type phenol resin, or the like can be used as a curing agent, and an imidazole compound, a second compound can be used as a curing accelerator. A tertiary amine compound or the like can be used. Moreover, also when a thermosetting resin is an epoxy resin and cyanate resin, an imidazole compound, a tertiary amine compound, etc. can be used as a hardening accelerator. These are blended in the aqueous emulsion resin liquid as they are, or after blending into an aqueous dispersion such as an emulsion or slurry, they are blended in the aqueous emulsion resin liquid.

  In addition to the resin composition, an inorganic filler can be blended if necessary. The inorganic filler can be added and mixed as it is in the aqueous emulsion resin liquid, but in order to facilitate dispersion in the aqueous emulsion resin liquid, a mixture or kneaded with a small amount of water may be used. By blending the inorganic filler, it is possible to prevent powder from falling off the prepreg as well as lowering the coefficient of thermal expansion and improving the heat resistance of the laminate without substantially reducing the properties of the prepreg and the laminate. Although it does not specifically limit as a compounding quantity, It is preferable that it is 30-80 weight% with respect to 100 weight% (solid content) of the whole composition containing resin and a filler, More preferably, it is 40-70 weight%. When the amount is less than the lower limit, the effect of reducing the flame resistance and the coefficient of thermal expansion may be insufficient. In particular, if the difference between the thermal expansion of components mounted on the laminated board is large, a problem may occur in reliability of a thermal cycle test or the like. On the other hand, if the upper limit is exceeded, the thixotropy of the resin liquid also increases, and the impregnation property and the appearance of the prepreg or the laminate may be lowered, and the workability such as drilling of the laminate tends to be lowered. is there. Moreover, a heat resistance fall may be seen from the relative shortage of resin.

Inorganic fillers include aluminum hydroxide, kaolin clay, hydrotalcite, attapulgite, sepiolite, mica, zinc stannate, silica, colemanite, brucite, talc, synthetic magnesium hydroxide, calcium carbonate, etc. Silica and talc are preferable for maintaining the average particle size, and the average particle size is preferably 0.2 to 5 μm in order to improve water dispersibility and impregnation. Accordingly, silica and talc having an average particle size of 0.2 to 5 μm are particularly preferable. Such an inorganic filler is preferably treated with a coupling agent, but a coupling agent may be added in advance to the aqueous emulsion resin liquid.

  In addition, additives such as an antifoaming agent, a leveling agent, an antioxidant, a surfactant, and a colorant can be blended in the resin composition used for the prepreg of the present invention as necessary.

  In the present invention, the fiber substrate used for the prepreg is not particularly limited, and examples thereof include woven fabrics or nonwoven fabrics such as glass fibers, fluororesin fibers, and aramid fibers, paper / glass fiber nonwoven fabrics, and the like from these fiber chops. A mat or the like can also be used.

Next, emulsification of the resin composition in the prepreg manufacturing method of the present invention will be described.
In the present invention, two or more kinds of thermosetting resins are combined as a resin composition and mixed by heating, melting and mixing. The thermosetting resin preferably has a softening point of 100 ° C or lower, or at least one of the thermosetting resins has a softening point of 40 ° C or lower. More preferably, a thermosetting resin having a softening point of 100 ° C. or lower and at least one of which has a softening point of 40 ° C. or lower is used in combination. Thereafter, the molten resin composition is dispersed in water to form an aqueous emulsion. The emulsification is usually performed by gradually adding and mixing an aqueous emulsifier solution to the heat-melted resin. The aqueous emulsifier solution is preferably heated to the same extent as the molten resin.

  In the conventional method, it is difficult to emulsify with a resin whose softening point is considerably higher than room temperature, and it has been pulverized into fine particles and dispersed in water to form a slurry. In the prescription using a plurality of resins, it is necessary to emulsify and slurry. Therefore, both the emulsion and the slurry are required for the equipment, which is a considerable equipment investment and the process of preparing the water-dispersed resin liquid is complicated. become. In the present invention, since two or more kinds of thermosetting resins are heated, melted and mixed to be emulsified, all the disadvantages of the conventional method are eliminated.

  As the emulsifier used in the present invention, among nonionic dispersants, some of polyoxyalkylene alkyl ether type such as polyoxyethylene alkyl ether type, polyoxyalkylene aryl ether type or polyoxyethylene fatty acid ester type may be used. Specifically, Emulgen A-500 (polyoxyethylene aryl ether type), Emulgen A-4085 (polyoxyethylene alkyl ether type), and Emulgen 220 (polyoxyethylene alkyl ether type) manufactured by Kao Corporation , Emanon 3199 (polyoxyethylene fatty acid ester type), Rheodor TW-S120V (polyoxyethylene fatty acid ester type), and the like. Further, as an aqueous solution type, there is Emulgen 1150S-70 (polyoxyethylene alkyl ether type).

  The content of the emulsifier is preferably 0.5 to 5 parts by weight with respect to 100 parts by weight of the resin solid content. More preferably, it is 1 to 4 parts by weight. If it is less than the above lower limit, the aqueous emulsion resin solution is unstable, and the time until the resin once emulsified is re-agglomerated tends to be short. If the upper limit is exceeded, the amount of emulsifier is excessive, and the heat resistance of the laminated board May adversely affect the properties and peeling properties, and increase the cost.

The emulsification method is not particularly limited. For example, a homogenizer, a disperser, and a clearer are added while gradually adding an emulsifier aqueous solution (preferably a heated emulsifier aqueous solution) to a thermosetting resin composition that has been previously heated and melted and mixed. A method of dispersing using a known stirring and mixing apparatus such as a mix is employed. The temperature at which the resin is heated and melted is usually such that the melt viscosity of the resin can be easily mixed when an aqueous emulsifier solution heated to the same degree is added and mixed.
The average particle size of the emulsion particles is preferably 30 μm or less, more preferably 10 μm or less. As a result, the emulsified resin liquid can be made to have a high concentration and a low viscosity, and the resin particles can easily enter between the fibers of the base material, so that the coating impregnation property is excellent. The high resin concentration of the aqueous emulsion resin liquid means that less energy is consumed for drying, and not only does not use an organic solvent, but also provides a formulation with a low environmental load. When the average particle diameter of the emulsion particles is larger than the above upper limit value, the dispersed emulsion particles may be re-aggregated and separated and precipitated.

  As described above, by heating and mixing two or more thermosetting resins into an aqueous emulsion resin liquid, there is no need for large capital investment, and the resin liquid has excellent handling properties and is impregnated into the fiber base material. Since it has excellent properties, it is extremely useful as a formulation that does not substantially use an organic solvent.

Next, other additives are blended into the aqueous emulsion resin liquid to obtain an impregnating resin liquid, and then the resin liquid is supported on the fiber substrate. Such a supporting method is not particularly limited. For example, the resin liquid is sprayed onto the base material using an spraying device such as a spray nozzle, the base material is immersed in the resin liquid, the knife coater. And a method of applying the resin liquid to the substrate with various coaters such as a comma coater, or a method of transferring the resin liquid to the substrate with a transfer roll.
Among these, in the method in which the resin liquid is applied to the base material by the spraying device, the resin liquid sprayed from the spraying device collides with the base material with energy, so that the impregnation into the base material is improved. It is preferable.

  In addition, when applying a method of spraying a resin liquid onto a base material using a spraying device or a method of immersing a base material in a resin liquid, it may be performed only by that method or carrying A comma coater, knife coater, squeeze roll, or the like may be used in combination to adjust the amount of the resin composition to be adjusted and to improve the smoothness of the prepreg surface.

In the method for producing a prepreg of the present invention, after the resin composition is supported on the substrate as described above, it is usually dried by heating. Thereby, substantially all of the water evaporates, and the resin component melts to lower the viscosity, so that a prepreg impregnated between the base fibers can be obtained. In addition, you may add heat until a resin component will be in a semi-hardened state as needed. Although it does not specifically limit as conditions to heat-dry, Usually, 100-220 degreeC, Preferably it carries out at 120-190 degreeC for 2 to 10 minutes.
The amount (solid content) of the resin composition supported on the prepreg is not particularly limited, but is usually about 40 to 60% by weight with respect to the entire prepreg (base material + resin composition).

  As described above, the method for producing the prepreg of the present invention comprises two or more thermosetting resins heated and melted and mixed, and the molten resin composition is dispersed in water to obtain an aqueous emulsion resin liquid. It carries on the said fiber base material, It is characterized by the above-mentioned. Thereby, a prepreg equivalent to the conventional one can be produced without substantially using an organic solvent. Further, when the thermosetting resin has a softening point of 100 ° C. or less, the resin can be easily melted and mixed and emulsified, and when the resin contains a softening point of 40 ° C. or less (including a liquid resin), the resin is heated. Melt mixing and emulsification become easy, and a prepreg in which the resin is sufficiently infiltrated between the monofilaments of the fiber substrate can be obtained. Furthermore, when the thermosetting resin has a softening point of 100 ° C. or lower, and at least one of them has a softening point of 40 ° C. or lower, the resin is further easily melted and mixed and emulsified, and the monofilament of the fiber base material A prepreg in which the resin is sufficiently infiltrated can be obtained.

The method for producing a laminated board is characterized in that the prepreg obtained by the above prepreg production method is subjected to heat and pressure molding. The heat and pressure molding can be performed under the same conditions as in the case of molding a prepreg from a resin varnish using a conventional organic solvent, for example, at a temperature of 170 to 200 ° C. and a pressure of 20 to 40 kg / cm ² . Heat and press for ~ 200 minutes. In this way, it is possible to obtain a laminated plate having excellent heat resistance and no voids, equivalent to the conventional one.
The method for producing a prepreg and the method for producing a laminate according to the present invention do not substantially use an organic solvent, so that resource saving, energy saving, and cost reduction are achieved, and further, improvement of the working environment and air pollution are achieved. It can also contribute to the reduction of.

  Hereinafter, the present invention will be described in detail with reference to examples. “Parts” and “%” described here all indicate “parts by weight” and “% by weight”.

Example 1
A biphenyl type epoxy resin (NC-3000H, manufactured by Nippon Kayaku Co., Ltd., softening point: 70 ° C.) is used as the epoxy resin, and a novolac type cyanate resin (Primaset, PT-30, manufactured by Lonza Japan Co., Ltd.) A softening point of 30 ° C. was used.

  50 g of epoxy resin and 50 g of cyanate resin were heated to 90 ° C. and melt mixed. On the other hand, 1.5 g of Emulgen A-500 manufactured by Kao Corporation was dissolved in 125 g of pure water as an emulsifier to prepare an aqueous emulsifier solution and heated to 90 ° C. Using a disperser, the above-mentioned aqueous solution of emulsifier was added in small portions over 10 minutes while stirring the heated and melted resin with a 40 mm stirring blade at 6000 rpm, and further stirred and mixed for 10 minutes. Thereafter, the mixture was cooled to 30 ° C. with stirring at 2000 rpm, and an aqueous emulsion resin solution having an average particle diameter of 5 μm and a resin concentration of about 45% by weight was prepared.

Next, 0.75 g of an imidazole compound (2PHZ · PW, manufactured by Shikoku Kasei Co., Ltd.) as a curing accelerator and silica treated with a coupling agent as a filler (Admafine SC2500-SE, Ad) 150 g of Matex Co., Ltd. (average particle size 0.5 μm) was blended to obtain a resin solution for impregnation.
This resin solution for impregnation was applied to glass cloth (manufactured by Nitto Boseki Co., Ltd., WE116E-S136, thickness 100 μm) by a spray method and dried by heating at 170 ° C. for 5 minutes to obtain a prepreg. The resin liquid solid content in the prepreg was 50% by weight.

Example 2
As the epoxy resin, 50 g of biphenyl type epoxy resin (Nippon Kayaku Co., Ltd., NC-3000H, softening point 70 ° C.) is used, and as the cyanate resin, two types of novolak type cyanate resins (Lonza Japan Co., Ltd., Primaset, 25 g each of PT-30 (softening point 30 ° C.) and PT-60 (softening point 60 ° C.) were used. Moreover, the compounding quantity of the silica (Admafine SC2500-SE, the product made from Admatex Co., Ltd.) which processed the coupling agent was 125 g. Except this, a prepreg was obtained in the same manner as in Example 1. The resin liquid solid content in the prepreg was 50% by weight.

Comparative Example 1
The epoxy resin and cyanate resin are the same as those used in Example 1.
These are used in a ratio of 1: 1 and dissolved in an organic solvent (methyl ethyl ketone) to obtain a varnish having a resin content of 50% by weight. Further, 1.1 g of an imidazole compound (2PHZ · PW) with respect to 100 g of resin solid content (200 g of varnish). Then, 150 g of silica (Admafine SC2500-SE) was added to prepare a varnish for impregnation. This varnish is made of glass cloth (Nittobo Co., Ltd.,
WE116E-S136) was applied by a dipping method and dried by heating at 170 ° C. for 5 minutes to obtain a prepreg. The varnish solid content in the prepreg was 50% by weight.

Comparative Example 2
In the same manner as in Example 1, a biphenyl type epoxy resin (NC-3000H) was used as an epoxy resin, and a novolac type cyanate resin (Primaset, PT-30) was used as a cyanate resin. Each of these resins was tried to be pulverized, but the cyanate resin had a low melting point, so that it could not be pulverized. Therefore, an aqueous dispersion slurry dispersed in an aqueous dispersant (emulsifier) solution could not be prepared.

Comparative Example 3
In the same manner as in Example 1, a biphenyl type epoxy resin (NC-3000H) was used as an epoxy resin, and a novolac type cyanate resin (Primaset, PT-30) was used as a cyanate resin. Each of these resins was heated and melted and dispersed in an aqueous emulsifier solution in the same manner as in Example 1 to prepare an emulsion. However, since the epoxy resin had a high melting point, it could not be formed into an aqueous emulsion.

Comparative Example 4
The epoxy resin and cyanate resin are the same as those used in Example 1.
The epoxy resin was coarsely pulverized with a feather mill, and further finely pulverized with a counter jet mill to an average particle size of 4 μm. 100 g of this finely pulverized epoxy resin and 1 g of Emulgen A-500 manufactured by Kao Co., Ltd. as a dispersant are mixed with an aqueous solution dissolved in 50 g of pure water, and stirred and mixed at 2000 rpm with a 40 mm stirring blade for 10 minutes. A water-dispersed slurry having an epoxy resin concentration of 66.7% by weight was obtained.

  On the other hand, the cyanate resin was melted by heating to 60 ° C. in an oven, and 100 g was weighed. 5 g of Emulgen 123P manufactured by Kao Corporation was dissolved in 50 g of pure water as an emulsifier and mixed with an aqueous solution heated to 90 ° C., and kept at 70 ° C. with a 40 mm stirring blade at 6000 rpm while keeping the temperature at 70 ° C. The mixture was stirred and mixed for 10 minutes, and then cooled to 25 ° C. while stirring at 2000 rpm to obtain an aqueous emulsion having an average particle size of 7 μm and a cyanate resin concentration of 66.7% by weight.

  These slurry and emulsion were mixed at a ratio of 1: 1 to obtain an aqueous dispersion resin liquid having a resin concentration of 66.7% by weight. At this time, aggregates were partially formed and precipitated. Immediately thereafter, 1.1 g of an imidazole compound (2PHZ · PW, manufactured by Shikoku Kasei Co., Ltd.) as a curing accelerator and silica treated with a coupling agent as a filler (Admafine SC2500-) with respect to 100 g of the resin content of the aqueous dispersion resin liquid SE) 150 g was mixed and stirred to obtain a resin solution for impregnation. Thereafter, a prepreg was obtained in the same manner as in Example 1. The resin liquid solid content in the prepreg was 50% by weight.

One prepreg obtained in Examples 1 and 2 and Comparative Examples 1 to 4 was used, and a single-side roughened copper foil having a thickness of 18 μm (manufactured by Furukawa Electric Co., Ltd., GTS-MP18) was layered thereon at 180 ° C. By heating and pressing at 30 kg / cm ^{2 for} 150 minutes, defoaming and molding were carried out while the thermosetting resin was being cured, and a copper-clad laminate was produced.

Tables 1 and 2 show the characteristics of the impregnating resin solution, the prepreg, and the laminate.

(Measuring method)
1. Storage stability of impregnating resin solution: Store the impregnating resin solution at 20 ° C., and set the number of days until the gel time (170 ° C. hot plate method) of the resin solution becomes half of the initial value every 5 days. It was measured.
2. Prepreg impregnation property: The prepreg was observed with an optical microscope (50 times), and the impregnation property of the resin solution for impregnation was evaluated based on the presence or absence of voids. The number of voids per 1 cm ² was 3 or less.
3. Prepreg storage stability: A prepreg was placed in an atmosphere at a temperature of 20 ° C. and a relative humidity of 40%, and was molded every 10 days under the above copper-clad laminate molding conditions, and the copper foil was etched to confirm the moldability. For the evaluation of formability, the presence or absence of voids in the laminate was visually observed, and the number of days until voids were determined was obtained.
4). Solder heat resistance of the laminated plate: In accordance with JIS C 6481, after 50 × 50 mm test pieces (10 pieces) were subjected to a pressure cooker moisture absorption treatment at 125 ° C. for 10 hours,
The test piece was floated in a 260 ° C. solder bath for 180 seconds, peeled off from the test piece, and the probability of occurrence of swelling was examined.
5. Copper foil peel strength: According to JIS C 6481, a test piece having a width of 10 mm was used, and the peel strength when the copper foil was pulled up at a right angle was measured.
6). Thickness direction thermal swelling rate: Measured up to 200 ° C. at a rate of temperature rise of 3 ° C./min with a thermal expansion measuring device (TA Instruments).

From the above results, in Examples 1 and 2, the impregnating resin liquid is an aqueous emulsion, and is excellent in preservability and impregnation properties even though no organic solvent is used. The laminate characteristics are also the same as the prepreg characteristics obtained by the conventional method of Comparative Example 1 and the laminate.
Comparative Example 2 is a case where the same two types of resins as in Example 1 were used and water dispersion slurries were prepared individually, and Comparative Example 3 was also similarly prepared using two types of resins and individually aqueous. This is a case where only an emulsion is to be prepared. In either case, a stable water-dispersed resin liquid could not be obtained. Comparative Example 4 is a case where a water-dispersed slurry and an aqueous emulsion are prepared according to the softening point of the resin, and these are mixed to obtain a resin liquid for impregnation. The slurry particles and the emulsion particles partially aggregate. The problem of clogging the spray nozzles occurred.

In the method for producing a prepreg of the present invention, two or more kinds of thermosetting resins are heated, melted and mixed, and then the molten resin composition is dispersed in water to form an aqueous emulsion resin liquid, which is used as the fiber base material. A stable aqueous emulsion resin solution can be prepared without substantially using an organic solvent, and a prepreg equivalent to the conventional one can be produced.
The laminate obtained by the laminate production method of the present invention has characteristics equivalent to those of a laminate produced by a conventional method using a resin varnish of an organic solvent.
In addition, since the prepreg manufacturing method and the laminate manufacturing method of the present invention do not substantially use an organic solvent, resource saving, energy saving, and cost reduction can be achieved, and further, the working environment can be improved. It can contribute to the reduction of air pollution, and is extremely useful as a method for producing prepregs and laminates for printed circuit boards, fiber reinforced plastics, and the like.

Claims (3)

In the manufacturing method of the prepreg comprised from a fiber base material and the thermosetting resin composition carry | supported by the said fiber base material, a softening point is 100 degrees C or less, At least 1 type is a softening point of 40 degrees C or less some more thermosetting resin heated and melted and mixed, thereafter, characterized in that the molten resin composition dispersed in water to form an aqueous emulsion resin solution, carrying the resin solution to the fibrous substrate A method for producing a prepreg. The method for producing a prepreg according to claim 1, wherein the thermosetting resin contains an epoxy resin and / or a cyanate resin. A method for producing a laminated board, wherein the prepreg obtained by the method according to claim 1 or 2 is heated and pressed.