JPH10139898A - Production of prepreg and production apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a prepreg hardly containing remaining babbles by using a liquid of a nonsolvent-type liquid resin. SOLUTION: This method for producing a prepreg comprises a step for coating a liquid 3 of a nonsolvent-type liquid resin on one surface of a sheet-like substrate 1, a step for impregnating the liquid 3 of the nonsolvent-type liquid resin into the sheet-like substrate 1 by heating the sheet-like substrate 1 coated by the liquid 3 of the nonsolvent-type liquid resin and lowering the viscosity of the liquid of the nonsolvent-type liquid resin, and a step for semihardening the resin-impregnated sheet-like substrate in the method for producing the prepreg by coating the resin liquid 3 on the one surface of the sheet-like substrate 1 comprising a fiber material, impregnating the resin liquid 3 into the sheet-like substrate 1 and heating the impregnated substrate 1 to provide the prepreg.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fibrous material such as paper and cloth used for manufacturing so-called laminated boards such as electric insulating boards such as printed wiring boards for industrial equipment and electronic equipment and decorative boards. The present invention relates to a method and an apparatus for producing a prepreg obtained by impregnating a sheet-like base material with a solventless resin liquid.

[0002]

2. Description of the Related Art Conventionally, when a resin material is continuously impregnated into a sheet material made of a fiber material, the sheet material is immersed in a resin solution dissolved with a solvent, and the resin solution is passed through the resin solution. An operation of impregnating the sheet-like base material is performed, but at this time, there is a limit to the penetration of the resin solution into the fine voids between the fibers of the sheet-like base material, and fine bubbles remain, and even after heating and drying, the prepreg is not used. The air bubbles are likely to remain in the prepreg, and voids are often generated in a laminate obtained by laminating the prepreg. Various methods of impregnating with a resin liquid have been proposed to reduce such residual air bubbles in the prepreg. For example, a method of applying a solvent or a low-concentration resin solution in advance and then immersing it in a high-concentration resin solution or a method and apparatus for vacuum-degassing a sheet-like base material are known, all of which improve the impregnation property. In this method, a solvent is used.

[0003]

In recent years, there has been a growing interest in environmental issues and a movement to regulate the use of solvents. On the other hand, it has been desired to manufacture a laminate using a solventless resin liquid from the viewpoint of cost reduction by reducing raw material costs, energy costs, exhaust gas treatment costs, and the like. However, the solvent-free resin liquid containing no solvent has very poor impregnation into the sheet-like fiber base material, and the conventional production method has many residual bubbles in the prepreg, and can satisfy the performance required for the electrical insulating plate. Could not be obtained.

The present invention has been made as a result of various studies in order to solve the above problems. It is an object of the present invention to provide a solvent-free resin liquid containing no solvent in a sheet-like substrate made of a fiber material. After application, the sheet-like base material coated with the solventless resin liquid is heated to have a viscosity equivalent to that of a resin liquid containing a commonly used solvent. It is an object of the present invention to provide a manufacturing method for obtaining a prepreg having few residual bubbles and satisfying the performance required for an electric insulating plate, and a manufacturing apparatus for optimally performing the method.

[0005]

According to the present invention, a prepreg is produced by applying a resin liquid to one side of a sheet-like base material made of a fibrous material, impregnating the sheet-like base material with the resin liquid, and heating. In the above, after applying a liquid solvent-free resin liquid on one side of the sheet-like substrate, the sheet-like substrate coated with the liquid solvent-free resin liquid is heated to reduce the solvent-less resin liquid. The present invention relates to a method for producing a prepreg, comprising heating the resin-impregnated sheet-like base material so as to make the resin semi-cured, by viscous impregnation into the fibrous interior of the sheet-like base material. is there.

That is, the prepreg manufacturing method of the present invention comprises a coating step of applying a liquid solvent-free resin liquid to one side of a sheet-like base material made of a fibrous material, The essential steps include a heating step of reducing the viscosity of the solventless resin liquid and a step of heating and semi-curing.

Further, depending on the type and properties of a sheet-like base material made of a fibrous material and a liquid non-solvent type resin liquid to be used for the same, the amount of resin adhering to a predetermined amount can be determined only by the step of coating on one side of the sheet-like base material. May not be enough. In this case, in order to adjust the amount of resin adhered after the heating step, a step of applying a liquid solvent-free resin liquid on the opposite side or both sides of the surface to which the solvent-free resin liquid was first applied, and then, A step of semi-curing by heating the solventless resin liquid applied first and the resin liquid applied for adjusting the amount of adhesion is provided.

[0008] The step of adjusting the resin adhesion amount may be performed only on the surface opposite to the surface on which the liquid solvent-free resin liquid is first applied, or from both surfaces, depending on the type of the sheet-like substrate and the resin liquid to be impregnated. It can be selected depending on the properties and the required quality of the prepreg to be obtained, but the former is more preferable in consideration of the cost of the apparatus and the balance of the amount of adhesion on both sides. It should be noted that the resin adhesion amount adjustment step does not need to be continuous with the previous step, and may be carried out once after winding up, but a winding up apparatus and man-hours are required.

On the other hand, a prepreg manufacturing apparatus of the present invention for carrying out such a method includes an apparatus for applying a liquid solvent-free resin liquid to one side of a sheet-like base material made of a fibrous material, and a sheet-like base material coated with the resin liquid. A device for heating the material, and configured to sequentially pass through a device for heating and semi-curing the resin-impregnated sheet base material, the type of the sheet base material to be used and the liquid solventless resin liquid to be impregnated, This is a prepreg manufacturing apparatus in which an adjusting device for adjusting the amount of adhered resin is further installed before the heating device depending on properties and the like.

The sheet-like base material made of the fiber material used in the present invention includes glass fiber base materials such as glass cloth, glass nonwoven fabric and glass paper, aromatic polyamide fibers, and the like.
Examples thereof include woven fabrics and nonwoven fabrics made of organic fibers such as aromatic polyester fibers, paper, and the like, woven fabrics and mats made of metal fibers and carbon fibers, and the like. These base materials may be used alone or as a mixture.

The liquid solvent-free resin liquid used in the present invention is a low-viscosity liquid at room temperature or is heated to an appropriate temperature so that curing does not proceed in order to uniformly apply it to a sheet-like substrate. This is a resin liquid that has been reduced in viscosity and made liquid. Examples of the resin that can be used for the laminate include an epoxy resin, an imide resin, a cyanate resin, a melamine resin, a phenol resin, a modified resin thereof, and a mixture thereof, and can be obtained by a known method.

As a component other than the above, a coloring agent, an ultraviolet absorber and the like can be added, if necessary, and a filler such as aluminum hydroxide, silica, talc,
Calcium carbonate or the like can be appropriately compounded as necessary. Further, the method of the present invention can be optionally carried out using a small amount of an organic solvent or a reactive diluent for each treatment. For example, when dicyandiamide is used as a curing agent in a liquid epoxy resin, a small amount of dimethylformamide or the like is used in order to dissolve dicyandiamide in the liquid epoxy resin. It is preferred that the amount of solvent per unit be about 10% by weight or less.

In the present invention, even when a liquid solventless resin liquid is used, the liquid solventless resin liquid is applied to one side of the sheet-like substrate, and then the sheet-like substrate coated with the resin liquid is heated. By heating the sheet-like base material and lowering the viscosity of the resin liquid at the same time, the impregnating property is equal to or more than that of the case where the resin liquid used in the conventional solvent and having the reduced viscosity is used. A prepreg with few residual air bubbles can be obtained even after a curing step.

Hereinafter, the steps of the present invention will be sequentially described. (Resin liquid application step) Instead of immersing a sheet-like substrate made of a fibrous material in a liquid solvent-free resin solution, a sheet-like substrate is continuously supplied, and a necessary amount is supplied from one side of the sheet-like substrate. This is the step of applying the liquid non-solvent type resin liquid. A coating device consisting of a fixed coater roll or a coater such as a doctor knife and a stationary or forward-rotating backup roll, and a liquid pump from a storage tank for non-solvent resin liquid are sent out by a gear pump or the like. It consists of a resin delivery device having a nozzle and the like arranged on one side of the material. The amount of the liquid non-solvent type resin liquid applied to the sheet-like substrate can be kept constant and uniform by carefully setting the feeding speed of the sheet-like substrate and the interval between the coater and the backup roll. Further, in order to uniformly apply the liquid solventless resin liquid to the sheet-like substrate, the guide roll may be a heat roll heated by electric heating, hot water, or the like, or may be a device equipped with a fixed heat plate. However, at high temperatures, the applied resin hardens,
It is preferable that the temperature of the surface in contact with the sheet-like substrate is 80 ° C. or less.

(Heating Step) A step of heating the sheet-like base material coated with the liquid solvent-free resin liquid, thereby lowering the viscosity of the resin liquid and easily replacing the air with the air in the fiber material. It is. By heating the liquid non-solvent type resin liquid, it is possible to obtain the same viscosity as the resin liquid containing a commonly used solvent. Furthermore, when the liquid resin is heated from the surface coated with the liquid solvent-free resin liquid, even if the resin liquid is heated and the viscosity is reduced before the sheet-shaped base material, the sheet-shaped base material has a lower temperature. Cannot be improved, which is not preferable. For this reason, it can be said that it is preferable to heat the sheet-like base material from the side opposite to the surface on which the resin liquid is applied, because the impregnating property is further improved. Although heating may be performed from both surfaces, it is clear that the effect is equal to or less than the above-described method in which heating is performed from the surface opposite to the surface on which the resin liquid is applied. The viscosity of the liquid solvent-free resin liquid by heating is usually 1 to 100 centipoise, preferably 5 to 30 centipoise. In order to reduce the temperature to 1 centipoise or less, the heating temperature must be considerably increased, and the curing of the resin proceeds and the resin is polymerized, thereby impairing the impregnating property. Above 100 centipoise, impregnation of the fiber material with the resin liquid is inferior, and a prepreg with few residual bubbles cannot be obtained.

(Heating and semi-curing step) In this step, a prepreg in which a liquid non-solvent type resin liquid is in a semi-cured state, that is, a so-called B stage, is obtained by heating a sheet-like base material after a heating step. Can be. The heating method may be a method conventionally used, and is not particularly limited.

[0017]

An embodiment will be described below with reference to FIGS. However, the present invention is not limited by these examples.

<< Example 1 >> A glass cloth 1 of 46 g / m2 was wound at a speed of 3 m / min, passed through a guide roll 8a, and rolled forward (or a stationary roll) 4b.
To a coating device 4 comprising a fixed type coater roll (or a coater such as a doctor knife) 4a. Using the solventless liquid resin liquid supply device 2 having a nozzle or the like disposed on the upper surface side of the glass cloth, the following solventless liquid epoxy resin liquid 3 in an amount of 220 g per minute is applied to the upper surface of the running glass cloth. . The gap between the roll 4b rotating forward and the coater 4a such as a fixed coater roll or doctor knife is adjusted to 0.15 mm in advance.

The glass cloth 1 coated with the solvent-free resin liquid on the upper surface is immediately transferred to a heating device 5 and heated from the lower surface with hot air at an ambient temperature of 120 ° C. for about 1 minute and 30 seconds to remove the solvent. After making the viscosity of the mold liquid resin liquid 27 centipoise and impregnating the glass cloth, both sides were heated and dried with hot air at an ambient temperature of 180 ° C. for about 1 minute in a heat-curing device 6 to obtain a resin amount of about 61 cm 2. % Prepreg was obtained.

(Solvent-free liquid resin composition) 50 parts by weight of liquid bisphenol A type epoxy resin (Epiclon 850, manufactured by Dainippon Ink and Chemicals, epoxy equivalent 184 to 194) 35 parts by weight of tetrabromobisphenol A (FR- 1542, BROMINE COMPOUNDS LTD.) ・ Phenol novolak 15 parts by weight (Sumilite Resin PR-51470P, manufactured by Sumitomo Bakelite) ・ 2-phenyl-4-methylimidazole 0.2 parts by weight (Curesol 2P4MZ, Shikoku Chemicals)

<< Embodiment 2 >> In this embodiment, 210 g /
The case of a glass cloth of m2 is shown. The epoxy resin liquid 3a is transferred to the coating device 4 at a speed of 3 m / min and coated on the upper surface side of the glass cloth at a rate of about 330 g per minute as in the first embodiment. A stationary or forward rotating roll 4b and a fixed coater roll or a coater 4 such as a doctor knife.
The gap of a is adjusted to 0.20 mm in advance. The glass cloth 1 coated with the resin liquid on the upper side is immediately heated 5
And heated from the lower side with hot air at an ambient temperature of 150 ° C. for about 1 minute and 30 seconds to reduce the viscosity of the resin liquid to 1
5 cp and after impregnating the glass cloth,
The resin liquid impregnated sheet is turned over by the guide rolls 7a and 7b, and the resin adhering amount adjusting device 9 having the same structure as the resin liquid supply device 2 applies the resin liquid impregnated sheet to the surface opposite to the surface on which the resin liquid is first applied, every minute. About 150 g of the resin liquid 3b is applied. At this time, the same resin liquid as the resin liquid 3a to be applied first was used (may be different). Then heat curing device 6
Both sides were heated and dried with hot air at an ambient temperature of 180 ° C. for about 2 minutes to obtain a prepreg having a resin amount of about 43%.

<Resin liquid composition> 30 parts by weight of liquid bisphenol A type epoxy resin (Epiclon 850, manufactured by Dainippon Ink and Chemicals, epoxy equivalent 184 to 194) 40 parts by weight of brominated bisphenol A type epoxy resin (Epiclon 153, (Epoxy equivalent: 390-410, bromine content: about 48%, manufactured by Dainippon Ink and Chemicals, Inc.) 25 parts by weight of phenol novolak resin (Sumilite Resin PR-51470P, manufactured by Sumitomo Bakelite) 0.3 parts by weight of dicyandiamide-dimethylformamide ( 3.0 parts by weight • 2-phenyl-4-methylimidazole 0.2 parts by weight (Curesol 2P4MZ, manufactured by Shikoku Chemicals)

The prepregs of Examples 1 and 2 were observed with a microscope at a magnification of 50 times, and the presence or absence of air bubbles in the prepreg was examined. As a result, the number of air bubbles was extremely small in each case, and a large amount of solvent was used. The number of bubbles was significantly smaller than that of the prepreg obtained by the usual immersion impregnation method using the epoxy resin liquid.

[0024]

According to the method of the present invention, a non-solvent type liquid resin liquid is applied to one side of a sheet-like substrate made of a fibrous material, and then the sheet-like substrate coated with the non-solvent type resin liquid is heated. By doing so, it is possible to lower the viscosity of the solventless resin liquid and impregnate the inside of the fibrous material of the sheet-like substrate. Unlike the conventional case, since the solvent is not substantially used, the cost can be reduced and the environment can be cleaned. Further, unlike the conventional case, it is not always necessary to use a vertical dryer, and a horizontal dryer can be used, so that the capital investment can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic side view showing a first embodiment of the present invention.

FIG. 2 is a schematic side view showing a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sheet-shaped base material 2 Resin liquid supply device 3, 3a, 3b Resin liquid 4 Coating device 4a Backup roll 4b Coater 5 Heating device 6 Heat curing device 7a, 7b Guide roll 8a, 8b Guide roll 9 Resin liquid supply device

Claims (6)

[Claims] 1. A method for producing a prepreg by applying a resin liquid to one side of a sheet-like base material made of a fibrous material, impregnating the sheet-like base material with the resin liquid and heating the sheet-like base material. A step of applying a liquid solventless resin liquid to one side of the sheet, and further heating the sheet substrate coated with the liquid solventless resin liquid to reduce the viscosity of the solventless resin liquid to form a sheet base. The process of impregnating the material,
A method for producing a prepreg, comprising a step of heating and semi-curing a resin-impregnated sheet-like substrate. 2. A method for producing a prepreg by applying a resin liquid to one side of a sheet-like substrate made of a fibrous material, impregnating the sheet-like substrate with the resin liquid and heating the sheet-like substrate. A step of applying a liquid solventless resin liquid to one side of the sheet, and further heating the sheet substrate coated with the liquid solventless resin liquid to reduce the viscosity of the solventless resin liquid to form a sheet base. The step of impregnating the material, the step of applying a liquid solventless resin liquid on the opposite side or both sides of the surface to which the solventless resin liquid was first applied, and furthermore, the resin impregnated sheet-like substrate is heated and semi-cured. A method for producing a prepreg, comprising the steps of: 3. The step of impregnating the sheet-like base material coated with the liquid solvent-free resin liquid by heating the sheet-shaped base material coated with the liquid solvent-free resin liquid, The viscosity is 1 to 100 centipoise (cps),
The method for producing a prepreg according to claim 1 or 2, wherein the method is a step of impregnating a sheet-like substrate. 4. An apparatus for applying a liquid solvent-free resin liquid to one side of a sheet-like substrate made of a fibrous material, an apparatus for heating the sheet-like substrate coated with the liquid solvent-free resin liquid, and a resin A heating device through which the impregnated sheet-shaped substrate passes. 5. An apparatus for applying a liquid solvent-free resin liquid to one side of a sheet-like substrate made of a fibrous material, an apparatus for heating the sheet-like substrate coated with the liquid solvent-free resin liquid, A device for applying a liquid solvent-free resin liquid to the surface or both surfaces opposite to the surface coated with the solvent-free resin liquid, and a heating device for passing the resin-impregnated sheet-like base material through. Pre-preg manufacturing equipment. 6. An apparatus for applying a liquid solvent-free resin liquid to one side of a sheet-like base material includes a heat roll which is stationary or forward rotating or a fixed heat plate for heating the sheet-like base material in advance. The prepreg manufacturing apparatus according to claim 5 or 6, which is an apparatus.