JPH11246687A - Production of prepreg and laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a good laminate not causing air pollution, capable of saving resources and having a stable quality at a low cost. SOLUTION: This method for producing a prepreg comprises giving mechanical energies to powdery components, respectively, consisting essentially of a powdery thermosetting resin and a powdery curing agent, to cause a mechanochemical reaction and subsequently disposing the obtained powdery resin composition at least on the surface of a sheet-like fiber substrate as such or after homogeneously mixed with a finely powdery additive having an average particle diameter of 0.01-1 μm. The method for producing a laminate comprises laminating one or more of the prepregs and subsequently heating and pressing the laminated prepregs.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a prepreg and a laminate, and more particularly to a method for producing a prepreg and a laminate suitable for a printed circuit board used in electric equipment, electronic equipment, communication equipment and the like. .

[0002]

2. Description of the Related Art As for printed circuit boards, demands for miniaturization and high performance are increasing, but price competition is intense. In particular, multilayer laminated boards, glass cloth base epoxy resin laminated boards, or glass used for printed circuit boards are used. The cost reduction of any laminate using nonwoven fabric as the intermediate layer base material and glass woven fabric as the surface layer base material has been a major issue. Conventionally, a large amount of a solvent has been used in a process for producing a prepreg or a laminate used for these. This is because the preparation of the resin varnish is easy, and the application and impregnation of the resin on the base material is uniform and easy. This solvent evaporates in a drying step after coating and does not exist in the product, and most of the solvent is treated by a combustion device or the like or released to the atmosphere as it is. It has been pointed out that this contributes to global warming and air pollution.
On the other hand, various measures have been taken to reduce the amount of solvent used,
This reduction was difficult due to manufacturing problems such as application and impregnation of the resin to the base material.

[0003] For the production of prepregs and laminates that do not use a solvent, studies have been made to heat and mix a low-melting-point resin or a liquid resin so as to be uniform and apply it to a base material. It is not possible to achieve sufficient production, and there are problems such as resin consolidation in equipment due to a decrease in heating temperature during continuous production, gelling of thermosetting resin during heating, and cleaning of equipment due to this. Was. On the other hand, a method of directly applying a powdery resin has also been proposed (Japanese Patent Application Laid-Open No. 50-14387).
No. 0), however, have problems such as difficulty in uniform mixing and coating, partial curing, and insufficient impregnation of the substrate, and have not been put to practical use.

[0004]

DISCLOSURE OF THE INVENTION The present invention has been studied to obtain a prepreg made of a resin that does not use a solvent and a laminate using the prepreg, which has been conventionally difficult to produce. By using it and applying a mechanochemical reaction to the powder, we obtained the knowledge that uniform mixing and impregnation into the substrate could be equivalent to that of a resin using a conventional solvent. Based on various studies, the present invention has been completed.

[0005]

According to the present invention, there is provided a powdery thermosetting resin and a curing agent which are essential components, and a mixture of these components is given a mechanical energy to cause a mechanochemical reaction to be carried out. A method for producing a prepreg, wherein a resin composition (hereinafter, referred to as a powder composition) is present at least on a surface of a sheet-like fiber substrate (hereinafter, referred to as a substrate). The present invention relates to a method for producing a laminate or a metal foil-clad laminate, comprising laminating one or more prepregs obtained as described above, and applying heat and pressure.

In the present invention, the powdery thermosetting resin used is preferably an epoxy resin. In addition, a polyimide resin, a polyester resin, a phenol resin and the like can be used. When the thermosetting resin is an epoxy resin, the curing agent is preferably an amine type, particularly dicyandiamide and an aromatic amine, and a novolak resin, in terms of heat resistance and electric characteristics, but acid anhydrides and imidazole compounds are also preferable. Can be used. The curing agent is preferably in the form of a powder, but when the amount is small (for example, 20% by weight or less with respect to the resin), the curing agent may be in a liquid state. It is possible. Preferably, a curing accelerator is used. The curing accelerator is preferably in the form of a powder, but a liquid accelerator can also be used as described above. As such a curing accelerator, an imidazole compound, a tertiary amine, or the like can be used. These components are not limited to those described above.

The particle size of these powders is usually 100
0 μm or less, preferably 0.1 to 500 μm, more preferably 0.1 to 200 μm. This is because if the particle size exceeds 1000 μm, the surface area with respect to the particle weight becomes small, the number of contact points of each component such as a thermosetting resin, a curing agent and a curing accelerator decreases, and uniform dispersion becomes difficult. It may react at a different ratio than the target ratio,
There is a possibility that a uniform reaction is not performed. For the mechanochemical reaction, when the curing agent and / or the curing accelerator is in a powder form, the particle size of the thermosetting resin is preferably 5 to 15 times the particle size of the curing agent and / or the curing accelerator. This is because the curing agent and / or the curing accelerator are easily fused to the thermosetting resin in this range.

[0008] The mechanochemical reaction is a "modification of solids by solids, surface modification of particles by pulverization, grinding, friction, contact, dissolution by transformation of crystal form and increase in strain energy, modification of rate of thermal decomposition". Or mechanical strength and magnetic properties, or surface activity is used to react with or adhere to other substances.Engineering uses mechanical impact energy to cause friction, electric charge due to contact, or Chemical modification as well as physical modification such as adhesion by magnetism, embedding of modifier in nuclear material, formation of film by melting, etc. are performed. " ,
The present invention utilizes chemical modification by a mechanochemical reaction, but also includes a case where solids and liquids are chemically modified by mechanical energy.

[0009] Powder processing methods for applying mechanical energy for the mechanochemical reaction include Raikai machines, Henschel mixers, planetary mixers, ball mills,
There is mixing or kneading by a jet mill, an ong mill, a multi-stage mill-type kneading extruder, or the like. Among these, Ongmill (Mechanofusion method manufactured by Hosokawa Micron Corporation), multi-stage mill-type kneading extruder (Made by KCK: Mechanochemical dispersion method, etc.), Jet mill (Nara Machinery Co., Ltd .: Hybridizer) And the like, and mixing or kneading is preferred. In order to efficiently carry out the mechanochemical reaction, a multi-stage mill-type kneading extruder (manufactured by KCK: mechanochemical dispersion method) is preferred.

[0010] In order to carry out the mechanochemical reaction, the softening point of the thermosetting resin is preferably 50 ° C or higher, more preferably 70 ° C or higher, and further preferably 80 ° C or higher. This is because heat of about 20 to 50 ° C. is generated due to friction, pulverization, and fusion between the powders or between the powder and the processing apparatus during the above-mentioned processing, so that this influence is minimized. On the other hand, if the softening point is too high, an effective mechanochemical reaction is unlikely to be performed, and it is difficult to impregnate the base material with the resin composition in a later step. Before the powder treatment for the mechanochemical reaction, each component such as the powdery thermosetting resin and the powdery curing agent should be ground to the above particle size in advance and mixed as uniformly as possible with a Henschel mixer. Is preferred.

The thermosetting resin composition used in the present invention may optionally contain an inorganic filler. When an inorganic filler is added, characteristics such as tracking resistance, heat resistance, and a decrease in coefficient of thermal expansion can be imparted. Such inorganic fillers include aluminum hydroxide, magnesium hydroxide, calcium carbonate, talc, wollastonite, alumina, silica, unfired clay, fired clay, barium sulfate and the like. These particle sizes are the same as above.

The particle size of the powder composition subjected to the mechanochemical reaction by the powder treatment is usually 1000 μm or less, preferably 0.1 to 500 μm, more preferably 0.1 to 200 μm. Such a particle size is to improve the fluidity of the powder composition at the time of spraying or application, and to improve the flow and surface smoothness at the time of heating and melting, to improve the resin impregnation property of the base material, It is suitable for stabilizing the distribution of the resin composition.

The powder composition obtained as described above is
It is made to exist on at least the surface of the substrate by spraying or coating. The amount of this powder composition depends on the fiber material of the base material, properties,
Although it depends on the weight (per unit area), it is usually about 40 to 60% of the weight of the substrate. The method of causing the powder composition to be present on the substrate includes a method of sprinkling from the upper surface of the substrate, an electrostatic coating method, a fluid immersion method, a spraying method with a spray, a knife coater, a coating method using various coaters such as a comma coater, and the like. There is no particular limitation. As the substrate, other than glass cloth, glass fiber substrate such as glass non-woven cloth, paper,
Woven fabrics and nonwoven fabrics made of synthetic fibers and the like, metal fibers, carbon fibers, woven fabrics made of mineral fibers and the like, nonwoven fabrics, mats and the like, and the raw material fibers of these substrates may be used alone or in combination. Good.

The powder composition may be present on the base material, and the powder composition may be present on one side of the base material. Preferably, the powder composition is provided on both surfaces of the base material in order to balance the front and back from the aspect of warpage or the like. It is preferred that the substance be present. This operation is usually performed on each side of the substrate. That is, after being made to exist on one surface, the powder composition is heated and adhered to the substrate, and then the same operation is performed on the other surface. Although the heating temperature depends on the softening point of the powder composition, it is usually 90 to 17 on the surface (lower surface) opposite to the surface to which the powder composition is attached for the above-described reason.
It is 0 degreeC, Preferably it is 110-150 degreeC. In addition, on the adhesion surface, the temperature is usually 80 to 150 ° C, preferably 100 to 140 ° C. The resin-impregnated base material may be heated in order to further sufficiently impregnate the resin composition and, if necessary, bring the resin into a semi-cured state. This heating temperature is
Usually, it is 100-200 ° C, preferably 120-1.
Although it is 90 ° C., it may be different depending on the fluidity and curability of the resin composition.

However, when the thickness of the substrate is as thin as 100 μm or less (100 g / m ² or less for a glass substrate) or when the powder composition is easily and uniformly melted, the powder composition is present only on one side. It may be a method. Again,
Usually, a step of heating and / or heating is provided thereafter.

The prepreg obtained as described above is
One or more of the sheets are laminated with a metal foil such as a copper foil as necessary, and heated and pressed by a usual method to form a laminate or a metal foil-clad laminate. The method for producing a prepreg and a laminate according to the present invention, the performance of the obtained prepreg or laminate, without substantially changing the conventional one,
The production by using the powder composition is facilitated, resource saving by solvent-free, energy saving and reduction of air pollution are achieved, and further cost reduction can be achieved.

The present invention is an application of the use of powder materials (resins, hardeners, etc.) and their mechanochemical reactions. By this technique, the components are uniformly dispersed and combined, and the resulting powder composition is obtained. When a product is present on a substrate and impregnated, uniform distribution and smoothness of a coated surface can be obtained, whereby uniform impregnation of the substrate can be achieved.

Hereinafter, with respect to the method of the present invention, typical examples will be sequentially described for each step with reference to the drawings. FIG. 1 is a schematic diagram showing an example of the steps of the method of the present invention.

(Powder Composition Mixing Step) A powder composition comprising a powdery thermosetting resin, a curing agent, and, if necessary, a curing accelerator is mixed uniformly while causing a mechanochemical reaction to occur. Then, it is charged into the fixed quantity supply device 4.

(Powder Composition Coating Step) A predetermined amount of the powder composition 3 subjected to the mechanochemical reaction treatment is supplied to a quantitative supply device 4.
From the upper surface side by a coater 5 or through a sieve.

(Heating Step) The substrate coated with the powder composition is heated by a heater 6 such as a hot air heater or a panel heater to melt the powder composition and adhere sufficiently to the substrate. This is a step of allowing air in the resin composition-adhered base material to easily escape together with the subsequent heating step. When the powder composition is present on the upper surface of the substrate and the lower surface is heated to a higher temperature or only the lower surface is heated, the impregnating property by the driving force due to the temperature difference between the molten resin and the substrate is improved. it can.

(Heating Step) If necessary, the powder composition is applied or adhered, and the heated substrate is heated by the heating device 7 to impregnate the resin further inside the substrate. The heating method may be a method conventionally used, and is not particularly limited.

(Resin Amount Adjusting Step) In order to prevent the powder composition from adhering to both sides of the base material in a well-balanced manner and to prevent warpage of the laminated board after molding, the powder composition is mixed with the base material after the heating or heating step. A step of adjusting the amount of resin adhered to the opposite surface is added. Usually, only the opposite surface is sufficient, but depending on the properties of the base material, it may be attached to both surfaces. Therefore, for this step,
Normally, the base material 8 having the powder composition adhered to one side is inverted, and a predetermined amount of the powder composition 9 is applied to the single-side resin-attached base material 8 from the quantitative supply device 10 by the coater 11 or through a sieve, Heating is performed by a heater 12 such as a hot air heater or a panel heater. This heating can be omitted. When an electrostatic coating method, a fluidized-bed method, or the like is used, the powder composition can be adhered without inversion.

(Heating Step) When there is a resin amount adjusting step,
It is preferable to provide a heating step as the next step. In this step, the prepreg can be obtained by heating the resin composition with the heating device 13 so that the resin composition is more sufficiently impregnated into the inside of the base material and, if necessary, the resin is semi-cured. it can. As the heating method, a method conventionally used may be used as in the heating step.

(Cutting Step) In order to form a laminated board, the prepreg 14 is cut to a required length by a cutting machine 15. When the prepreg is subjected to continuous molding, this cutting step is omitted.

In FIG. 1, the substrate is of a type in which the substrate is moved in a horizontal direction, and the whole apparatus used is of a horizontal type. It is also possible to adopt a method of spraying a pre-heated sheet on a base material. In this case, a vertical device is employed.

[0027]

Next, examples of the present invention will be specifically described together with comparative examples.

Example 1 100 parts by weight of a powdery epoxy resin having an average particle diameter of 150 μm (brominated epoxy resin Ep5048, manufactured by Yuka Shell Epoxy Co., Ltd., epoxy equivalent: 675), and curing of a powder having an average particle diameter of 15 μm. 5 parts by weight of an agent (dicyandiamide) and a powdery curing accelerator (2-ethyl-4-methylimidazole) having an average particle size of 15 μm 1
Parts by weight and then processed using a multi-stage mill-type kneading extruder (Mechano-Chemical Dispersion System KCK-80X2-V (6) manufactured by KCK Co., Ltd.) at a rotation speed of 200 rpm for 1 minute. A powder composition having a diameter of 150 μm was obtained. This powder composition was coated on the upper surface of a 100 g / m ² glass cloth with a knife coater so that the resin weight was 5%.
The coating was uniformly performed so as to be 0 g / m ² . Thereafter, the panel was heated from the lower surface side by a panel heater at 150 ° C. and 120 ° C. for about 1 minute. Next, the glass cloth was turned upside down, and the resin weight was 50 g / m ^{2 on the} other side using a knife coater.
And apply with a hot air heater at 170 ° C.
Heated for a minute to obtain a prepreg. The prepreg overlay two further superimposed copper foil having a thickness of 18μm on the upper and lower, temperature 165 ° C., at a pressure 60 kg / cm ² 90
The molded body was heated and pressed for one minute to produce a copper-clad laminate having a thickness of 0.22 mm.

Example 2 100 parts by weight of a powdery epoxy resin (Ep5048) having an average particle size of 150 μm, 5 parts by weight of a powdery curing agent (dicyandiamide) having an average particle size of 15 μm, and a powder having an average particle size of 15 μm 1 part by weight of a curing accelerator (2-ethyl-4-methylimidazole) in the form of a mixture was preliminarily mixed, and then a mechanofusion machine (AM-15F manufactured by Hosokawa Micron Corp.) was used.
The mixture was treated at 0 rpm for 5 minutes to obtain a powder composition having an average particle size of 150 μm. This powder composition was passed through a 60-mesh sieve on one side of a 100 g / m ² glass cloth and uniformly sprinkled so that the resin weight became 50 g / m ² . Then, the glass cloth was heated from both sides with 170 ° C hot air heater.
Heat for 0 seconds, then turn the glass cloth upside down and pass the other side through a 60 mesh sieve to reduce the resin weight to 50
g / m ² , and uniformly heated to 170 ° C. with a hot air heater for 3 minutes to obtain a prepreg. Using this prepreg, a thickness of 0.22 mm was obtained in the same manner as in Example 1.
Was produced.

Example 3 100 parts by weight of a powdery epoxy resin having an average particle diameter of 150 μm (the above-mentioned Ep5048), 5 parts by weight of a powdery curing agent (dicyandiamide) having an average particle diameter of 15 μm, and a powdery form having an average particle diameter of 15 μm Pre-mixed at a ratio of 1 part by weight of a curing accelerator (2-ethyl-4-methylimidazole) of the formula (5) with a Henschel mixer at a rotational speed of 5 parts.
The mixture was treated at 00 rpm for 5 minutes to obtain a powder composition. Using this powder composition, a prepreg was obtained in the same manner as in Example 2. Two prepregs are laminated, and a copper foil having a thickness of 18 μm is laminated on the upper and lower sides of the prepreg, and is heated and pressed at a temperature of 165 ° C. and a pressure of 60 kg / cm ² for 90 minutes to form a copper-clad laminate having a thickness of 0.22 mm. A plate was made.

Example 4 5 parts by weight of a powdery curing agent (dicyandiamide) having an average particle diameter of 15 μm, and an average particle diameter of 15
A mixture of 1 μm of a μm powdery curing accelerator (2-ethyl-4-methylimidazole) mixed at a ratio of 1 part by weight was used as a mechanofusion machine (AM-15F, manufactured by Hosokawa Micron Corporation).
2,000 rpm for 2 minutes, and then a powdery epoxy resin having an average particle size of 150 μm (the Ep504
8) 100 parts by weight were mixed, and the mixture was further treated with the mechanofusion machine at a rotation speed of 2000 rpm for 3 minutes to obtain a powder composition. A prepreg was obtained in the same manner as in Example 2 using this powder composition. Two prepregs are laminated, and a copper foil having a thickness of 18 μm is laminated on the upper and lower sides of the prepreg, and is heated and pressed at a temperature of 165 ° C. and a pressure of 60 kg / cm ² for 90 minutes to form a copper-clad laminate having a thickness of 0.22 mm. A plate was made.

Example 5 The powder composition obtained in Example 1 was uniformly applied to one side of a glass cloth of 210 g / m ^{2 using} a knife coater so that the resin weight became 90 g / m ² . Thereafter, the mixture was heated from the lower surface side by a hot air heater at 120 ° C. for about 1 minute. Next, turn the glass cloth upside down, and weigh 90 g of resin on the other side with a knife coater.
/ M ^2, and heated for 1 minute with a hot air heater at 170 ° C. to obtain a prepreg. Two prepregs were superimposed, and a copper foil having a thickness of 18 μm was superimposed on top and bottom of the prepreg, at a temperature of 165 ° C. and a pressure of 60 kg / cm ^2.
For 90 minutes to produce a copper-clad laminate having a thickness of 0.42 mm.

Example 6 A powdery epoxy resin having an average particle size of 150 μm (brominated epoxy resin Ep manufactured by Yuka Shell Co., Ltd.)
5048, epoxy equivalent 675) 100 parts by weight, powdered phenol novolak resin having an average particle diameter of 30 μm (Phenol Novolak PR-51470 manufactured by Sumitomo Durez, Inc.)
Phenolic hydroxyl equivalent 105) 16 parts by weight, premixed at a ratio of 1 part by weight of powdery triphenylphosphine having an average particle diameter of 10 μm, and then a multi-stage mill-type kneading extruder (Mechanochemical dispersion system manufactured by KCK Co., Ltd.) Using KCK-80X2-V (6)) for 1 minute at a rotation speed of 200 rpm, a powder composition having an average particle size of 150 μm was obtained. This powder composition was coated on the upper surface of a 100 g / m ² glass cloth with a knife coater so that the resin weight was 5%.
The coating was uniformly performed so as to be 0 g / m ² . Thereafter, the panel was heated from the lower surface side by a panel heater at 150 ° C. and 120 ° C. for about 1 minute. Next, the glass cloth was turned upside down, and the resin weight was 50 g / m ^{2 on the} other side using a knife coater.
And apply with a hot air heater at 170 ° C.
After heating for a minute, a prepreg was obtained. Two prepregs were superimposed, and a copper foil having a thickness of 18 μm was further superimposed on the two prepregs at a temperature of 175 ° C. and a pressure of 20 kg / cm ² .
The molded body was heated and pressed for one minute to produce a copper-clad laminate having a thickness of 0.22 mm.

Comparative Example 1 A powdery epoxy resin having an average particle size of 150 μm (brominated epoxy resin Ep manufactured by Yuka Shell)
5048, epoxy equivalent 675) 100 parts by weight, powdery curing agent (dicyandiamide) 5 having an average particle size of 15 μm 5
Parts by weight and 1 part by weight of a powdery curing accelerator (2-ethyl-4-methylimidazole) having an average particle size of 15 μm are mixed by stirring with an anchor-type stirrer at a rotation speed of 70 rpm for 1 minute. A composition was obtained. Using this powder composition, a prepreg was obtained in the same manner as in Example 1, and then a copper-clad laminate having a thickness of 0.22 mm was produced using this prepreg.

Comparative Example 2 A powdery epoxy resin having an average particle size of 150 μm (brominated epoxy Ep50 manufactured by Yuka Shell Co., Ltd.)
48) 100 parts by weight, 5 parts by weight of a powdery curing agent (dicyandiamide) having an average particle diameter of 15 μm, and an average particle diameter of 15 μm
After mixing at a ratio of 1 part by weight of a powdery curing accelerator (2-ethyl-4-methylimidazole), the powder composition was heated and melted at 100 ° C., and then 100 g as a resin solid content
/ M ² , soaked and impregnated with 100 g / m ² glass cloth, and heated with a heating device at 170 ° C for 2 minutes to obtain a prepreg. Two prepregs are laminated, and a copper foil having a thickness of 18 μm is laminated on the upper and lower sides of the prepreg, and is heated and pressed at a temperature of 165 ° C. and a pressure of 60 kg / cm ² for 90 minutes to form a copper-clad laminate having a thickness of 0.22 mm. A plate was made.

Comparative Example 3 A powdery epoxy resin having an average particle size of 150 μm (brominated epoxy Ep50 manufactured by Yuka Shell Co., Ltd.)
48) 100 parts by weight, 5 parts by weight of a powdery curing agent (dicyandiamide) having an average particle diameter of 15 μm, and an average particle diameter of 15 μm
Was mixed with 1 part by weight of a powdery curing accelerator (2-ethyl-4-methylimidazole) in 100 parts by weight of methylcellosolve. The varnish was impregnated with 100 g / m ² glass cloth so as to have a resin solid content of 100 g / m ^2, and then heated with a hot air heater at 170 ° C. for 3 minutes to obtain a prepreg. This prepreg is 2
A copper foil having a thickness of 18 μm is laminated on the upper and lower sides, and the temperature is 165 ° C. and the pressure is 60 kg / cm ² .
It was heated and pressed for 0 minutes to produce a copper-clad laminate having a thickness of 0.22 mm.

In the above Examples and Comparative Examples, for the prepreg, the impregnation of the resin into the glass cloth was measured, and for the copper-clad laminate, the moldability, tensile strength, copper foil peeling strength, and solder heat resistance were measured. The properties were measured. The results are shown in Tables 1 and 2.

[0038]

[Table 1]

[0039]

[Table 2]

(Measurement method) Impregnating property: The prepreg was observed with a stereoscopic microscope, and the presence or absence of voids between glass fibers was confirmed. 2. Formability: The copper foil of the copper-clad laminate was etched, the presence or absence of the precipitation of a curing agent or the like was visually observed, and the dispersibility of the resin composition was evaluated. 3. Tensile strength: Etching copper foil of copper clad laminate,
After cutting to 10 × 100 mm, the tensile strength was measured with Tensilon. 4. Copper foil peel strength: Measured according to JIS C6481. 5. Solder heat resistance: A laminate of 50 × 50 mm is subjected to 260 ° C.
Was floated in a solder bath for 3 minutes, and the presence or absence of blisters was measured. 6. Insulation resistance: Measured according to JIS C6481.

As for the manufacturing cost, since the method of the embodiment does not use a solvent, the laminated board obtained in the embodiment is reduced in cost by about 30 to 40% as compared with that obtained in the comparative example 3. Was completed. Moreover, about the comparative example 2,
In the step of melting the resin at 100 ° C., the change over time in the curing characteristics of the resin was remarkable, and the resin adhered to the equipment hardened, making cleaning difficult.

[0042]

According to the method of the present invention, a laminate having good quality such as electric characteristics and heat resistance can be stably obtained even though no organic solvent is used. Since no organic solvent is used, resource saving, energy saving, and reduction of air pollution are achieved, and resource saving and energy saving are also excellent in terms of cost reduction. Thus, the present invention is suitable as an industrial method for producing a prepreg and a laminate.

Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI // B29K 105: 06

Claims (4)

[Claims] 1. A powdery resin composition obtained by using a powdery thermosetting resin and a curing agent as essential components and applying a mechanical energy to a mixture of these components to cause a mechanochemical reaction to obtain a sheet-like fiber. A method for producing a prepreg, wherein the method is present on at least a surface of a substrate. 2. The method for producing a prepreg according to claim 1, wherein the curing agent is a powdery curing agent. 3. The method for producing a prepreg according to claim 1, wherein the apparatus for causing the mechanochemical reaction is a jet mill, an ong mill, or a multi-stage mill-type kneading extruder. 4. A method for producing a laminate or a metal foil-clad laminate, comprising laminating one or more prepregs obtained by the method according to claim 1, 2, or 3 and heating and pressing.