JPH11254435A - Film for manufacture of prepreg, prepreg and manufacture of film and prepreg - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a wide and extremely thin resin film for a low resin weight per unit area prepreg for manufacturing a molded body of good quality and quality level generating a small amount of resin loss and provide its manufacturing method and also manufacture a low resin weight per unit area prepreg of good quality level using the film. SOLUTION: Resin of 50 cm width or more is applied on a release sheet in the setting of the 20 g/m<2> average weight per unit area or less and at 100% weight per unit area unevenness or less and the volatile content is 4 wt.% or less for the manufacture of a resin film for manufacturing a prepreg, and a prepreg using the film and the manufacturing methods for the film and the prepreg are also provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin film suitable for producing a prepreg impregnated with a fiber-reinforced resin, and a prepreg using the resin film and having a uniform resin content distribution. In particular, the present invention has a fiber basis weight of 50 g / m
^A resin film for producing a prepreg having a width of 50 cm or more suitable for uniformly and uniformly producing a molded article having a thickness of ² or less, or a molded article having a high fiber content having a resin content of 30% or less, and a uniform resin basis weight Having a resin basis weight of 20 g /
m ² or less, preferably relates prepreg or less 10 g / m ^2.

[0002]

2. Description of the Related Art Conventionally, a molded article having an extremely thin weight and a molded article having a high resin content are once produced in a so-called A stage or B stage state by a filament winding method or a prepreg method, and are then molded. Have been obtained.

[0003] These are usually prepared by preparing an intermediate having a target resin weight substantially equal to the target weight and molding them, or by preparing an intermediate having a resin amount higher than the final target weight of the molded article. It has been manufactured by flowing and squeezing a resin in a molding stage to adjust a basis weight. However,
When an intermediate with the target weight of resin is manufactured by the filament winding method, the resin impregnation is not uniform, voids are frequently generated in the molded product, the quality of the molded product is poor, and the mechanical properties are insufficient. Point. On the other hand, in the method using a prepreg, a resin film is usually prepared on release paper, and a fiber is impregnated with the prepreg to prepare a prepreg.In particular, it is difficult to prepare a low-weight resin film having a width of 50 cm or more. The impregnation unevenness was caused by the spots and the prepreg quality was not preferable.

[0004] An improvement of this method, in which the resin is caused to flow out and squeezed in the prepreg molding step, is disclosed in Japanese Patent Publication No. 6-98.
As shown in Japanese Patent No. 627, a molded article having relatively good quality and quality can be obtained, but not only loss of resin flowing out, but also special materials must be used as auxiliary materials used for molding. There was a need to improve on economics. Further, a method of directly applying a resin to a yarn when preparing a prepreg has been proposed as in Japanese Patent Publication No. 9-31219, but in this method, the viscosity of the resin to be used is limited, or the width of the resin is limited. The impregnation was not uniform in the direction and in the longitudinal direction of the yarn, and it was difficult to form a wide product having a width of about 50 cm or more without unevenness, and the characteristics of the molded product were not improved. Further, a method in which the resin is dissolved in an appropriate solvent and directly supplied to the carbon fiber is also conceivable, but there is a problem that a uniform resin content cannot be obtained, and voids are generated when the remaining solvent is volatilized. There were also improvements such as the need for a solvent treatment step to prevent this.

In a method in which a resin is dissolved in a solvent and once supplied onto release paper, a resin film is manufactured by a method in which the coating is made thicker and then the solvent is evaporated.
In a wide release paper having a width of 0 cm or more, the basis weight is likely to be uneven in the width direction, and the basis weight is likely to be uneven in the longitudinal direction due to a change in the solvent concentration over time. There are problems such as infiltration into release paper, and voids in the residual solvent during molding.

Japanese Unexamined Patent Publication (Kokai) No. 3-123671 discloses a method in which a molten resin is supplied to an applicator roll using a die, and the resin is stretched when supplied. Manufacturing methods are known. However, when a wide resin film is to be obtained by this method, unevenness in the width direction increases, and there is a problem that a complicated improvement is required in die equipment.

Further, Japanese Patent Application Laid-Open No. 3-123670 proposes a method for controlling a resin basis weight by controlling a roll speed ratio using a reverse roll coater, and produces a film having a thickness of about 15 μm. That is, it is described that a particle having a large particle diameter in a resin is coated. However, specific conditions for obtaining an extremely thin and highly accurate resin film in a wide film have not been disclosed.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a wide and ultra-thin resin film for a prepreg having a low resin weight, which is capable of obtaining a molded article having good quality and quality and having little resin loss. And a low-quality resin with good quality using them, for example, a resin weight of 20
It is to provide a prepreg having a g / m ² or less, preferably 10 g / m ² or less. In particular, the present invention is suitably applied to a prepreg having a resin content of 30% by weight or less or a fiber weight of 50 g / m ² or less.

[0009]

Means for Solving the Problems A resin film for producing a prepreg of the present invention has the following constitution to solve the above-mentioned problems. That is, the resin is applied on the release sheet with a width of 50 cm or more and an average basis weight of 20 g / m ² or less, and a basis weight variation of 10% or less as defined in the text, and a volatile content of 4% by weight or less. A resin film for producing a prepreg. Such a resin film is prepared by applying a resin to release paper using a reverse roll coater having a width of 50 cm or more having a metalling roll and a coating roll to produce a resin film for prepreg production. C, and
The release paper speed P satisfies the following relational expression:
It can be suitably obtained by a method for producing a resin film for producing a prepreg.

0.5 ≦ M / C ≦ 2 (1) 0.4 ≦ C / P ≦ 1.5 (2) The prepreg of the present invention has the following features to solve the above-mentioned problems. Having a configuration. That is, in a prepreg having a width of 50 cm or more in which a sheet-like reinforcing material made of reinforcing fibers is impregnated with a resin, the average resin weight in the prepreg is 20 g / m ² or less, and the volatile content is 3% by weight or less. A prepreg characterized in that the resin basis weight variation defined therein is 10% or less. Such a prepreg can be suitably obtained by a method for producing a prepreg, wherein the resin film is brought into contact with a sheet-like reinforcing material made of reinforcing fibers from one side or both sides and heated and pressed.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

In the resin film of the present invention, the resin has a width of 50 cm or more on the release sheet, an average weight of 20 g / m ² or less, preferably 10 g / m ² or less, and a variation in the weight of 10% or less, preferably 5%. It is necessary that the composition be applied below and that the content of volatile components be 4% by weight or less, preferably 3% by weight or less. If the variation in the basis weight exceeds 10%, there is a problem that unevenness of the prepreg is produced when the prepreg is produced, and in a severe case, the prepreg is impregnated or cracked in a portion using a resin film having a low basis weight. They are,
The average basis weight had the significant disadvantage of a resin film exceeding 20 g / m ^2, an average basis weight has been a serious problem in case of manufacturing a prepreg by the following low basis weight resin film 20 g / m ^2.

In the present invention, the average basis weight and the basis weight variation of the resin are measured as follows.

The average basis weight of the resin was an average of the basis weight in the width direction and the basis weight in the longitudinal direction. In addition, the variation in the basis weight was expressed as an average value of the variation in the width direction and the variation in the longitudinal direction represented by the variation rate (CV value).

(1) Weight of resin film in width direction The resin film is sampled so as to be even in the width direction, and the weight of the resin film is measured by a gravimetric method. The size of the cut sample is 10 cm × 10 cm. Width 50c
For the resin film of m, the measurement is performed at n = 4 excluding both ends, and for the resin film of 1 m, the measurement is performed at n = 9 excluding both ends.

(2) Weight of resin film in longitudinal direction A center portion in the width direction of the resin film is sampled every 10 cm into a size of 10 cm × 10 cm over a length of 4.1 m and measured by a gravimetric method. (N = 21) In order to apply the molten resin in a thin film on release paper,
Knife coater, blade coater, air blade coater, reverse roll coater, etc. are used.In order to apply the resin in a thin film form with less unevenness in the present invention, it is necessary to apply the resin under specific conditions using a reverse roll coater. Preferably, even if other coaters are used, a resin having a minimum viscosity of 0.1 poise to 300 poise is used.
It may be difficult to apply the coating with a width of 50 cm or more with few spots.

The resin used in the present invention has a minimum viscosity of 0.1 to 300 poise, preferably 1 to 300 poise, as measured by the following method.
It is a thermosetting resin having a viscosity of 150 poise, preferably an epoxy resin.

In the present invention, the resin viscosity is measured by using a dynamic viscoelasticity method. For example, when an RDA-II type device manufactured by Rheometrics is used as the dynamic viscoelasticity measurement device, the measurement is performed under the following conditions. Here, as the temperature rises, the viscosity of the resin decreases, and thereafter a curing reaction occurs to start increasing. The viscosity in the present invention is a viscosity showing a minimum value measured under the following conditions. The resin temperature at that time is defined as the minimum viscosity temperature. In the embodiments described later,
An RDA-II type device manufactured by Rheometrics was used.

Operation mode: dynamic frequency 3.1
4 radians / sec Heating rate: 1.5 ° C./min Plate composition: parallel plate (25 mm radius), gap 1.
00 mm.

If the minimum viscosity of the resin is lower than 0.1 poise, the resin film cannot be formed uniformly, causing problems such as flow and repelling. Further, there is a problem that the resin adheres to the back surface of the release body and the separator. on the other hand,
If it exceeds 300 poise, the film is not evenly formed. In addition, when transferring the resin from the coating roll to the release paper, a transfer unevenness is generated so that a uniform resin film cannot be obtained. Or drape is insufficient, and a good molded body cannot be obtained. In addition,
In order to prevent the above problems by raising the temperature at the time of coating, in the case of a thermosetting resin,
Since curing starts, stable coating is difficult.

The resin film of the present invention can be obtained by adopting specific conditions when coating the resin using a reverse roll coater.

That is, the metering roll speed M and the coating roll speed C in the reverse roll coater,
The release paper speed P is set so as to satisfy the following relationship.

0.5.ltoreq.M / C.ltoreq.2 (1) 0.4.ltoreq.C / P.ltoreq.1.5 (2) More preferably, the following relationship should be satisfied.

0.5 ≦ M / C ≦ 1.2 (3) 0.4 ≦ C / P ≦ 1.2 (4) First, the ratio of the metering roll speed M to the coating roll speed C is calculated as follows. It is necessary to be 2 or less, preferably 1.2 or less and 0.5 or more. When M / C is more than 2, there is a problem that the spots on the film increase. If the M / C is less than 0.5, it is difficult to set conditions for obtaining an ultrathin film, and the amount of spots increases. In the case of a remarkable condition, the clearance between the coating roll and the metering roll can be maintained. The possibility of breakage of the rolls.

Usually, the speed ratio M / C of the metering roll and the coating roll in the reverse roll coater is:
For example, Harazaki, "Coating method" (Maki Shoten 1988
6th printing per year P. Although it is used at 0.35 or less as shown in 89), different condition settings are used in the present invention.

On the other hand, C / P is 1.5 or less, preferably 1.2 or less. In order to produce a low-weight resin film having a C / P of more than 1.5, it is necessary to set the distance between the coating roll and the metalling roll to be narrow. In addition, there is an increase in the number of streaky defects that are not coated with a resin having a width of 1 mm or more, which may cause defects in the prepreg, and may cause breakage due to too close roll intervals. C / P needs to be applied at 0.4 or more. If it is less than 0.4, the resistance of stretching the resin when transferring the resin to the release paper increases, so if the winding is uneven and severe, the release paper will be destroyed,
When resin is transferred, spots are likely to occur. Here, the release paper speed P is controlled by the speed of the backup roll, the nip pressure, and the winding tension, so that a predetermined C / P ratio condition can be obtained.

A more preferred C / P range is 0.5 to
0.9.

In the reverse roll coater, the ratio of the coating roll speed C to the release paper speed P is usually 0.4 or less as described in the above-mentioned publication. However, in the present invention, different condition settings are used. Can be

The basis weight of the resin to be applied is determined by setting the resin under the above-mentioned roll conditions without using a solvent by one minute from the lowest viscosity temperature.
Melting is performed at a temperature of 0 ° C. or higher and at a temperature of 50 ° C. lower than the minimum viscosity temperature, and the clearance between the metalling roll and the coating roll is set to a predetermined amount to obtain a target resin weight basis film. If the resin is melted and coated at a temperature higher than the minimum viscosity temperature by 10 ° C., in the case of a thermosetting resin, the viscosity of the resin becomes unstable due to the effect of the curing reaction, and it becomes difficult to prevent a change with time. On the other hand, if the coating is performed at a temperature lower than the lowest viscosity temperature by 50 ° C., the viscosity is too high, and a viscosity unevenness due to a temperature unevenness or the like is generated, so that it is difficult to produce the resin film of the present invention with less unevenness.

In the present invention, the viscosity of the resin at the time of coating is from 1 to 2000 poise, preferably from 10 to 800 poise.
Poise is good. When it exceeds 2,000 poise, it becomes difficult to produce a resin film having a uniform basis weight, especially with a basis weight of 10 g / m ² or less. On the other hand, if it is less than 1 poise, a portion where the resin does not adhere, that is, so-called coating unevenness occurs, which is not preferable.

At this time, the resin raw material is adjusted by grinding using a three-roll mill, filtering or other methods so as not to contain a cured product of the resin, coarse particles, and foreign matter, and by applying the above-described conditions, the width of the resin is reduced to 1 mm. It is possible to obtain a resin film not having the above-mentioned resin-free streaky defects having a width of 5 lines / m or more, preferably 3 lines or more.

Preferably, the resin film of the present invention is produced on a release sheet having an appropriate release force and surface tension. These are typically release paper or a plastic film having a surface subjected to release treatment, and the release treatment is preferably silicone treatment. It is sufficient that the surface to which the resin adheres is subjected to a release treatment, but the back surface may be subjected to a release treatment having a release force different from that of the front surface.

The resin used in the present invention is preferably a thermosetting resin, such as an epoxy resin, a polyester resin, a vinyl ester resin, a phenol resin, a bismaleimide resin, and a polyimide resin. More preferably, an epoxy resin is used.

Examples of the epoxy resin used for these are, for example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, biphenyl type epoxy resin, naphthalene type epoxy resin, dicyclopentadiene type epoxy resin and fluorene type epoxy resin which are bifunctional resins. A resin or a combination thereof is preferably used.

Examples of the trifunctional or higher-functional polyfunctional epoxy resin used for these include phenol novolak type epoxy resin, cresol novolak type epoxy resin, glycidylamine such as tetraglycidyldiaminodiphenylmethane, triglycidylaminophenol and tetraglycidylamine. A type epoxy resin, a glycidyl ether type epoxy resin such as tetrakis (glycidyloxyphenyl) ethane or tris (glycidyloxy) methane, or a combination thereof is preferably used.

As the curing agent used for these, aromatic amines such as diaminodiphenylmethane and diaminodiphenylsulfone, aliphatic amines, imidazole derivatives,
Of carboxylic acid anhydrides such as dicyandiamide, tetramethylguanidine, thiourea-added amine, methylhexahydrophthalic anhydride, carboxylic acid hydrazide, carboxylic acid amide, polyphenol compound, novolak resin, polymercaptan, and boron trifluoride ethylamine complex And the like.

Also, those obtained by microencapsulating these curing agents can be suitably used in order to enhance the storage stability of the prepreg.

These curing agents can be combined with an appropriate curing accelerator to increase the curing activity. Preferred examples include dicyandiamide with 3- (3,4-
Dichlorophenyl) -1,1-dimethylurea (DCMU)
And the like, and examples of combining a carboxylic acid anhydride or a novolak resin with a tertiary amine as a curing accelerator.

The epoxy resin and the curing agent, or a product obtained by preliminarily reacting a part of the curing agent and the curing agent, can be incorporated into the composition. This method may be effective for adjusting viscosity and improving storage stability in some cases.

In addition to the above components, a thermoplastic resin may be blended for the purpose of controlling the viscosity of the resin and controlling the handleability of the prepreg. Preferred examples of the compatibility with the epoxy resin, such as having no adverse effect on the physical properties of the composite material, include polyvinyl formal, polyvinyl butyral,
Examples include polyethylene oxide, polymethyl methacrylate, polyamide, polyester, polyethersulfone, polysulfone, polyetherimide, and polyimide. Further, two or more of these resins may be mixed. As additives, rubber particles, soluble rubber,
Core-shell rubber or the like can be included. These are at least partially dissolved in the base resin or present in the form of particles without being dissolved, but in the present invention, in order to obtain a prepreg of good quality without streaks, when the particles are present, the particle size is substantially reduced. It is preferable that the particles are previously pulverized or dissolved so that those having a size of about 50 μm or more are not contained.

In the present invention, a resin material having a low volatile content is selectively used or used after removing the volatile component, and is used in a resin adjusting step, a film manufacturing step, and a prepreg forming step. 4% by weight of volatile matter in resin film
Hereinafter, preferably 3% by weight or less, the obtained resin film is used in the prepreg step while preventing moisture absorption, and furthermore, by preventing the obtained prepreg from absorbing moisture, the volatile content in the prepreg is reduced to 3% by weight or less. Preferably, it is necessary to be 2% by weight or less. In the case where such a method is not used, volatile components remain in the final prepreg, which causes a problem that the voids of the molded article increase or the quality is deteriorated.

As the sheet-like reinforcing material made of reinforcing fibers, a sheet-like material obtained by aligning a plurality of reinforcing fibers in one direction and a woven fabric obtained by weaving the reinforcing fibers can be used. As the reinforcing fibers, carbon fibers are preferably used from the viewpoint of their mechanical properties.

The resin film having a basis weight of 20 g / m ² or less and a width of 50 cm or more obtained in the present invention is converted into a sheet-like reinforcing material made of reinforcing fibers in a prepreg forming step which is continuous or separated from the film forming step. On the other hand, supply so as to match from above, below, above, or below, heating,
By applying pressure, the fiber is impregnated with the resin to form an integrated prepreg. The heating temperature at this time is preferably +50 to −40 ° C. with respect to the minimum viscosity of the resin.
Further, the pressure cannot be unconditionally determined by the pressure application mechanism, but it is more preferable to apply a relatively low pressure in two or more stages than to apply a high pressure in one stage. A preferred method of applying pressure is 0.5 to 30 kg / cm as a calculated linear pressure in three stages,
Preferably, it is in the range of 1 to 15 kg / cm. If the pressure is too low or the temperature is too low, impregnation of the resin may be insufficient, and defects such as fiber gaps may occur. On the other hand, when an excessive pressure is applied to the prepreg, the fluff of the fibers is generated, and the variation in the resin areal weight tends to increase.

By selecting these conditions, it is possible to reduce the variation in resin weight by 10% using the resin film of the present invention.
The following prepregs can be obtained.

The variation in the basis weight of the resin of the prepreg is measured as follows.

The prepreg is sampled in the width direction of the prepreg at the same sampling interval as the basis weight of the resin film, and the prepreg weight is measured. Thereafter, the resin content is removed with an extract of an organic solvent capable of dissolving the matrix resin, the weight of the remaining fiber is measured, and the weight of the prepreg is subtracted to obtain the resin weight. Make this measurement 1
The average value and the variation rate (CV value) are obtained by repeating three points every m. This variation rate is referred to as resin weight variation of the prepreg.

[0047]

EXAMPLES The present invention will be described more specifically below with reference to examples.

Examples 1 to 7 and Comparative Examples 1 to 4 35 parts of phenol novolak type epoxy resin and 65 parts of bisphenol A type epoxy resin were added with dicyandiamide 4
Parts, 3 (3,4-dichlorophenyl) 1,1 'dimethyl urea 5 parts were uniformly blended, and the epoxy resin whose minimum viscosity was adjusted to 20 poise and minimum viscosity temperature 120 ° C was melted at 70 ° C and released on release paper. Using a three-roll type reverse roll coater, coating was performed by changing the ratio of the coating roll speed C to the release paper speed P and the ratio of the coating roll speed C to the metalling roll speed M as shown in Table 1. Was carried out to prepare a resin film having a coating width of 100 cm. Here, the speed of the release paper is 10 to 25.
m / min.

The properties of the resin film obtained here are shown in Table 1.
Shown in The resin viscosity at the time of coating was 800 poise. The volatile content of the resin film was 1 to 2.5% by weight as measured under each condition.

[0050]

[Table 1] Comparative Example 5 A resin film was prepared in the same manner as in Example 6, except that the temperature during coating was changed to 60 ° C. At this time, the resin viscosity was 2,200 poise. The average basis weight of the resin fluctuated in a short period of time from 10 to 12 g / m ² , the variation in the basis weight increased to 10% or more, and the coating state became unstable.

Comparative Example 6 The molecular weight of the epoxy resin was changed and the coating temperature was changed to 9
By setting the temperature at 0 ° C., the viscosity at the time of coating is 0.5
A resin film was prepared in the same manner as in Example 6 except that poise was adjusted. Spotted uncoated portions of the resin resulted in the coated resin. Further, when coating is performed for a long time, there is a problem that the resin is partially cured.

Example 8 The resin film obtained in Example 6 was supplied from the lower surface of a sheet in which carbon fibers having a fineness of 0.2 g / m and a number of filaments of 3000 were aligned in one direction, and only one surface was measured from the upper surface. Is supplied with a release agent treated with a release agent, and the carbon fiber basis weight is 30 g /
A prepreg having an m ² and a width of 100 cm was prepared. Heating temperature is 120 ° C and pressurization is the calculated linear pressure at the maximum of 10kg
/ Cm and pressurized in 3 steps, resin weight variation 5
% And a resin content of 25% by weight.

[0053]

According to the present invention, a wide ultra-thin resin film for a prepreg having a low resin weight, which is capable of obtaining a molded article having good quality and quality and low resin loss, and good quality using the same. A low resin weight prepreg can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of an apparatus suitable for producing a resin film of the present invention.

[Explanation of symbols]

 41: Release paper unwinder 42: Release paper 43: Unwound release paper 44: Backup roll 45: Coating roll 48: Resin film winding body 50: Resin melting roll 51: Metering roll 57: Roller slit 60: Resin the film

Claims (14)

[Claims] 1. A resin having a width of 50 cm or more on a release sheet and an average weight of 20 g / m ² or less, and a weight variation 1 defined in the text.
0% or less applied and volatile content 4% by weight
A resin film for producing a prepreg, comprising: ^2. A weight variation as defined in the text, wherein the resin has a width of 50 cm or more and an average weight of 10 g / m ² or less on the release sheet.
0% or less applied and the volatile content is 3% by weight
A resin film for producing a prepreg, comprising: 3. The resin film for prepreg production according to claim 1, wherein said resin is a thermosetting resin having a minimum viscosity of 0.1 to 300 poise as defined in the text. 4. The method according to claim 1, wherein said resin is an epoxy resin.
3. The resin film for producing a prepreg according to any one of 3. 5. The resin film for producing a prepreg according to claim 1, wherein the number of streak defects having a width of 1 mm or more is less than 5 / m per resin film width. 6. A prepreg having a width of 50 cm or more obtained by impregnating a resin into a sheet-like reinforcing material made of reinforcing fibers,
The average resin weight in the prepreg is 20 g / m ² or less,
A prepreg having a volatile content of 3% by weight or less and a resin weight variation as defined in the text of 10% or less. 7. The prepreg according to claim 6, wherein the average resin weight is 10 g / m ² or less and the volatile matter content is 2% by weight or less. 8. The prepreg according to claim 6, wherein the resin is a thermosetting resin having a minimum viscosity of 0.1 to 300 poise and a resin content of the prepreg is 30% by weight or less. . 9. The resin is a thermosetting resin having a minimum viscosity of 0.1 to 300 poise and a prepreg fiber weight of 5
8. The composition according to claim 6, wherein the content is 0 g / m ² or less.
Prepreg. 10. When a resin film is applied to release paper using a reverse roll coater having a width of 50 cm or more having a metalling roll and a coating roll to produce a resin film for prepreg production, a metalling roll speed M and a coating roll speed are used. A method for producing a resin film for producing a prepreg, wherein C and the release paper speed P satisfy the following relational expression. 0.5 ≦ M / C ≦ 2 (1) 0.4 ≦ C / P ≦ 1.5 (2) 11. The method for producing a resin film for prepreg production according to claim 10, wherein the metering roll speed M, the coating roll speed C, and the release paper speed P satisfy the following relational expression. 0.5 ≦ M / C ≦ 1.2 (3) 0.4 ≦ C / P ≦ 1.2 (4) 12. The resin has a minimum viscosity of 0.1 to 300.
A poise thermosetting resin, the resin viscosity at the time of coating is 1 to 2000 poise, and the obtained resin film has an average basis weight of 20 g / m ² or less, and a basis weight variation of 10% or less as defined in the text. Claim 10 or 11
A method for producing a resin film for producing a prepreg. 13. The method according to claim 13, wherein the average basis weight is 10 g / m ² or less.
A method for producing a resin film for producing a prepreg according to claim 12. 14. A method for producing a prepreg, comprising bringing the resin film of claim 1 or 2 into contact with a sheet-like reinforcing material made of reinforcing fibers from one side or both sides, and applying heat and pressure.