JPH01235605A - Method for manufacturing prepreg - Google Patents

Abstract

PURPOSE:To reduce the use of organic solvent in a manufacturing process as well as enable the method for manufacturing the prepreg having few void and uniformity by further pressurizing and heating via pressure medium the prepreg placed under the decompressed state by a decompression mechanism. CONSTITUTION:By passing through a pair of squeeze rollers 3, 3, the resin is forcedly dispersed into a base material 1. Between both metallic belts 11, 14, the base material 1 is held via separation films 8, 8 and a cylindrical suction pipe 15 and a rod-shaped seal member 16 are provided at regular intervals with the base material 1 so as to suck the unnecessary moisture and organic solvent contained in the resin through suction of a vacuum pump. The sucked resin impregnated base material is transferred to a pressure container 13, and then applied a certain temperature and pressure from both upper and lower surfaces of the metallic belts 11, 14, thus the resin is dispersed and infiltrated uniformly into the base material and the prepreg passed through the pressure container 13 acts to remove the separation films after passing through driving pulleys 10, 10, so that a desired prepreg single body may be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for manufacturing prepreg used as a laminate material.

(Prior Art) As a conventional prepreg manufacturing method, there is a method in which a base material is impregnated with a synthetic resin and then dried.

Now, to explain this based on FIG. 3, a base material 1 made of cotton linter paper or the like is first impregnated with synthetic resin varnish in an impregnating tank 2, and then passed through squeeze rolls 3 to remove excess resin. A portion of the prepreg is squeezed out, roughly dried in a drying oven 4, and then cut into an appropriate size using a cutter 5 to obtain a desired prepreg 6.

In the above method, when impregnating the base material 1 with a synthetic resin in the impregnation tank 2, the resin is diluted with an organic solvent in advance, and the above-mentioned base material is placed in a resin varnish that has been adjusted to have an ia degree and viscosity that facilitate penetration. Impregnating the material 1 with resin by immersing it,
Thereafter, the prepreg 6 is obtained by passing through a drying oven 4 to evaporate the organic solvent.

(Problems to be Solved by the Invention) However, in the above-mentioned method, since an organic solvent is used, there are problems such as the risk of ignition and explosion and the occurrence of air pollution due to pollution.

In addition, the obtained prepreg contains trace amounts of unreacted substances and organic solvents, and during the subsequent laminate manufacturing process, these unreacted substances and organic solvents develop into minute voids and become harmful. In addition, there was a problem in that the quality characteristics of the laminate were also impaired.

In view of the above-mentioned problems, an object of the present invention is to reduce the use of organic solvents in the manufacturing process and to provide a method for manufacturing a prepreg with fewer voids.

(Means for Solving the Problems) The present invention involves sandwiching a base material impregnated with a liquid resin between sheet-like materials, vacuuming the inside of the space formed by the sheet-like materials to remove volatile components, and then The present invention relates to a method for manufacturing a prepreg, which is characterized in that the prepreg is passed through a heated and pressurized pressure medium while being sandwiched between sheet-like materials.

Next, the present invention will be explained based on the drawings.

FIG. 1 is a schematic diagram of the apparatus used in the present invention, in which 1 is a base material wound around a roller (not shown), and includes cotton linter paper, kraft paper, glass cloth, glass fiber 1gJ<15
, plastic nonwoven 15, etc.

In addition, 7 is a resin dripping device, in which synthetic resins, thermosetting liquid resins (epoxy resins, phenolic resins, melamine resins, silicone resins, unsaturated polyester resins, acrylic resins, etc.) are dispersed in appropriate organic solvents. A concentrated resin or a solvent-free liquid resin is dropped onto the base material 1, and the resin is forcibly dispersed into the base material 1 by passing between a pair of squeeze rolls 3, 3. ing.

For this reason, it is preferable that the squeeze rolls 3, 3 are heating rolls.

Further, reference numerals 9, 9', and 10.10- are drive pulleys for conveying the base material provided opposite to each other, a metal belt 11 is provided between the pulleys 9 and 10, and a metal belt 14 is provided between the pulleys 9- and 10'. is suspended.

In addition, between pulleys 9 and 9', 9' is 1 more than the other pulley 9.
It is provided 50 cm in front of Qcm (on the left side in FIG. 1) and is configured to facilitate the supply of the base material 1.

8.8' is a release film inserted between the base material 1 and both metal belts 11.14, and the film 8.8' unwound from the release film unwinding roller 18.18'' is
The release film is configured to be taken up by a take-up roller 17.17-.

The release film used is preferably a polyester film, Teflon film, aluminum foil film, etc., which have excellent heat resistance and solvent resistance.

Next, 12 is a preheating section provided immediately after the base material 1 passes between the pulleys 9, 9-, and is heated with steam, electric heat, etc. at 40 to 100°C to lower the viscosity of the resin in the base material. It is configured to promote resin dispersion, suck out unnecessary water and organic solvents generated by heating, and reduce pressure.

FIG. 2 is a perspective view showing the depressurization structure in the preheating section 12, in which the base material 1 is held between the metal belts 11 and 14 via release films 8, 8- (not shown). At the same time, a cylindrical suction tube 15 and a round bar-shaped sealing material 16 are provided at a constant interval from the base material 1.

That is, the suction pipe 15 is disposed approximately to the center in the width direction between both metal belts, and one side opening 15B of the suction pipe is connected to a vacuum pump (not shown), and the other side opening 15B is connected to a vacuum pump (not shown). The portion 15A is opened between the base material 1 and the sealing material 16, and is configured to suck out unnecessary moisture and organic solvent contained in the resin by suction from the vacuum pump.

On the other hand, as a result of the suction of unnecessary moisture and organic solvent as described above, the base material 1 is configured to be placed under reduced pressure between both belts.

As the suction pipe 15, a plastic pipe or the like having excellent heat resistance can be used.

Further, the sealing material 16 is arranged to have the same length as the width direction of both metal belts 11 and 14, and serves to seal between both metal belts and prevent pressure medium from entering the pressure vessel, which will be described later. , a diameter larger than the thickness of the base material 1 and the diameter of the suction tube 15 is used.

The sealing material used may be a tube, an elastic round cord, a flat plate, or the like.

Materials include fluororubber, polytetrafluoroethylene, silicone rubber, nitrile rubber, chloroprene rubber, etc. Depending on the material, 1 to 3 pieces may be used.
The larger the number, the better the sealing performance. In addition, sufficient sealing performance can be obtained even when disposable cardboard is used. Also, when using flexible sealing materials,
If a metal band slightly thicker than the base material, plastic suction tube, etc. is provided at the outer end for sealing, the sealing performance will be further improved.

The resin-impregnated base material sucked as described above is transported to the pressure vessel 1.
3, and by applying constant temperature and pressure from both the upper and lower surfaces of the metal belts 11 and 14, the resin is further uniformly dispersed and impregnated into the base material. On the other hand, gas, solvent, etc. generated within the pressure vessel are discharged via the suction pipe 15 in the front.

In addition, as the pressure vessel 13, Japanese Patent Application Laid-Open No. 61-17971
The one described in No. 1 is used and heats and pressurizes with a pressure medium.

That is, the inlet and outlet sides of the pressure vessel are cooling zones, which are configured to cool and solidify the pressure medium and maintain the pressure within the pressure vessel.

As the pressure medium, pressure media that are solid at room temperature and stable even after heating, such as paraffin and polyethylene wax, are preferred.
The melting point is 50 to 100°C, and it is preferably liquid at 100 to 170°C at h0 heat.

The prepreg that has passed through the pressure vessel 13 as described above then passes through the driving boolean JI0, 10-, and then the release film is peeled off to obtain a desired single prepreg.

Moreover, even if the mold release film is applied to the cutting machine 5 and cut into a regular length, a void-free prepreg can be obtained.

(Explanation of Examples) Next, the present invention will be explained based on examples.

Example 1 A paper base cotton linter paper (130g/c+++2) was pre-primed with a water-soluble phenol resin, and a liquid epoxy resin was poured onto the dried base material and temporarily dispersed using a squeeze roll. .

Next, the upper and lower sides were covered with Mylar film (35 μm), further sandwiched between stainless steel belts, and the vacuum level of the pressure vessel was set at 100 Torr, the preheating temperature was 60°C, and the temperature at the entrance and exit of the pressure vessel was 20°C using the apparatus shown in Figure 1. It was heated to 130'C using industrial normal paraffin as a pressure medium, and the set pressure was 5kCl/C1112.

In addition, the conveyance speed is 2 m/min, and the total length of the pressure vessel is 20 m/min.
It was set as m.

A laminate plate obtained by laminating and molding the prepregs obtained under the above conditions had excellent heat resistance and water resistance.

Example 2 Liquid epoxy resin was dropped and dispersed on an epoxy silane treated base material of glass cloth (0.10 mm thick), the upper and lower sides were covered with polyethylene film (38 μm thick), the material was sandwiched between stainless steel belts, and the apparatus shown in Fig. 1 was prepared. 80' at the preheating section.
The mixture was heated to C and further suctioned at a suction vacuum level of 50 torr.

Next, it was sent to a pressure vessel, and polyethylene wax was used as the pressure medium in the pressure vessel, the heating temperature was 140°C, and the set pressure was 15 kg/cm 2 .

In addition, the conveyance speed is 2 m/min, and the total length of the pressure vessel is 20 m/min.
It was set as m.

The prepreg obtained in the above manner was evaluated as having no voids.

Furthermore, as a result of manufacturing a laminate using the above prepreg, the laminate had no voids that occur during interlayer adhesion and had fewer molding defects.

(Effects of the Invention) As described above, the prepreg manufacturing method according to the present invention obtains a prepreg by further pressurizing and heating the prepreg placed under reduced pressure by a pressure reducing mechanism via a pressure medium, so it is a solvent-free type. It is possible to mold resin prepregs, and since the amount of solvent used is small, there is no danger of explosion and no need for pollution prevention facilities. Further, since vacuum suction can be performed, a void-free prepreg can be obtained, and since pressure and temperature are uniformly applied to the prepreg, a uniform prepreg can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of the apparatus used in the present invention, and FIG.
A partially detailed perspective view of the figure and FIG. 3 are schematic diagrams showing a conventional prepreg manufacturing method. 1...Base material 6...Prepreg 13...Pressure vessel 15...Suction pipe 16...Sealing material No. 2 16-"y-41° Fig. 3

Claims (1)

[Claims] 1. A base material impregnated with a liquid resin is sandwiched between sheet-like materials, and the inside of the space formed by the sheet-like materials is vacuum-suctioned to remove volatile components, and then heated and pressurized while being sandwiched between the sheet-like materials. A method for producing prepreg characterized by passing the prepreg through a pressure medium.