JPS5910295B2 - Manufacturing method of prepreg sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a method for manufacturing a prepreg sheet by impregnating a fiber base material such as a glass chopped strand mat, a woven fabric, or a combination thereof with roping, etc., with a liquid resin. .

More specifically, the present invention particularly involves continuously impregnating a substrate with low strength, such as glass chopped strands, with a liquid resin, and using double-sided release paper only on one side of the target impregnated material. This relates to a technology for winding up into a roll. Conventionally, SMC (
SheetMoldingCompund)
As shown in FIG. 1, the manufacturing process for 5MC is as follows: First, a polyethylene film 1 is coated with an appropriate amount of the liquid resin composition 3, and a glass chop formed by cutting the roping 2 into an appropriate length with a chopper 5 is placed on top of it. After scattering and covering the polyethylene film coated with the liquid resin composition 3', the glass chops were pressed with a presser roll 8 to impregnate the glass chops with the resin.

After defoaming and winding up into a roll with polyethylene films 1 and 2 on the top and bottom surfaces, the material is heated and aged, thereby producing the desired SMC material. In FIG. 1, 4 and 4' represent doctor blades, 6 a side shield, T a belt, and 9 a wine turret. However, products made using this method use 10 pieces of polyethylene film on both the top and bottom surfaces, which are no longer needed during use, resulting in a large amount of wasted material and additional industrial waste. Furthermore, there is a drawback that defoaming is insufficient in the step of impregnating the fiber base material with the liquid resin (the step of pressing with the presser roll 8). The present invention has been made in order to eliminate the drawbacks of the prior art, and uses a liquid resin to impregnate fiber base materials such as glass chopped strands and glass chopped strand mats, which have extremely weak bonding strength between fibers. An object of the present invention is to provide a method for manufacturing a prepreg sheet that can effectively remove air bubbles even when impregnated with a prepreg sheet. For this reason. In the present invention, when manufacturing a prepreg sheet by impregnating a fiber base material with a liquid resin, the liquid resin is laminated on one side of a six-sided release sheet, and the fiber base material is superimposed on top of the liquid resin to form a laminated sheet. This laminated sheet is passed between a roll having a comb-like peripheral surface and two support rolls that support this roll, and the fiber base material of the laminated sheet is pressed by the comb-like roll, and further, the fiber base material of the laminated sheet is After pressing the fiber base material of the laminated sheet with a circumferential comb-shaped roll that reciprocates in the forward and reverse directions with respect to the direction in which the sheet travels, the fiber base material is pressed while pressing the other side of the double-sided release sheet of the laminated sheet with a nip roll. The present invention is characterized in that the laminated sheet is wound up so that the surface faces inside, and that the laminated sheet is transported by a suction belt constituted by a mesh belt and a suction box.

The configuration of the present invention will be explained in detail below.

The double-sided release sheet used in the present invention is a sheet that has releasability on both sides with respect to the prepreg sheet, and is, for example, a commercially available double-sided release paper or a polyethylene sheet.
An appropriate double-sided release sheet may be selected in consideration of the adhesiveness of the final product prepreg sheet.
The liquid resin used in the present invention is, for example, in the form of a composition obtained by mixing an unsaturated polyester resin, a vinyl ester resin, an epoxy resin, or a urethane resin with a curing agent and the like. The fiber base material to be impregnated with such a liquid resin may be a common material, such as a glass chopped strand mat, a continuous mat, a nonwoven fabric or felt made of organic fiber, or an organic fiber woven fabric. Inorganic fiber woven fabric or a combination of these. FIG. 2 shows an example of the manufacturing process of the prepreg sheet of the present invention, in which the double-sided release paper 10 is
9 , one side of which is coated with liquid resin 11 by means of a temperature-adjustable doctor knife 12 and a temperature-adjustable back roll 13 .

Note that the device for coating 6 liquid resin is a doctor knife 12 and a back roll 13 as a metering device.
Due to the temperature controllable structure, depending on the viscosity of the coating resin,
The temperature can be adjusted to the optimum temperature for coating, and in the impregnation process, by moving the sheet onto the hot bed 23,
It is possible to lower the resin viscosity to a state where it is easy to impregnate.
The temperature of the hot head 23 may be adjusted to an optimum temperature depending on the viscosity characteristics of the resin used. The fiber base material 14 is superimposed on the liquid resin coated on one side of the double-sided release paper 10 in this manner. Next, it is made to pass between a fixed impregnation roll 15 with a comb-like peripheral surface and two support rolls 16 that support this to promote impregnation into the fiber base material. This comb-like impregnation roll 15 comes into direct contact with the fiber base material, but by making the roll surface comb-like, even when glass chopped strands are used as the base material, glass hops will not adhere to the roll. Furthermore, defoaming during impregnation can be effectively carried out without damaging the shape of the mat. The fiber base material impregnated with a certain amount of resin by the fixed comb-like impregnating roll 15 is passed between the comb-like impregnating roll 17 and the hot head 23, which reciprocate in the forward and reverse directions with respect to the direction of travel. The resin impregnation and defoaming are completely carried out. This movable comb-like impregnating roll 17 is different from the fixed impregnating roll 15 described above. It is characterized by high impregnation and defoaming effects. Fixed impregnation roll 15 and support roll 1
6 naturally rotates in the direction of the arrow as the seat moves. The movable comb-like impregnating roll 17 is reciprocated in the direction of the arrow by an electric motor or an air cylinder. By directly forcibly pressing the fiber base material with the six-comb roll, the base material can be impregnated with the resin and defoamed very effectively. The movable comb-like impregnating roll 17 may not only reciprocate in the forward and reverse directions, but also reciprocate in the left and right directions at the same time. The impregnating roll portion is shown in an enlarged view in FIG. 3. Further, FIG. 4 is a plan view of the comb-like impregnation rolls 15 and 17. The sheet is transferred by pressing the sheet onto the mesh belt at atmospheric pressure using a suction belt constituted by a mesh belt 18 and a suction box 20, and simultaneously rotating the mesh belt 18.

In addition to this drive method, a pitch type tender etc. can also be used, but the suction belt method is effective when using a release sheet etc. that is not strong. By transferring the six sheets without contacting one side of the sheet in this way, in other words, the surface of the fiber base material of the sheet does not come into contact with other objects (for example, rolls), and furthermore, when winding the product, it is possible to wind it with low tension. Since it can be removed, there is no resin leakage due to tightening b, and therefore a homogeneous product can be obtained. Note that by winding up the double-sided release sheet while pressing it with a nip roll, it is possible to prevent air from entering during winding, and furthermore, any remaining air bubbles can be defoamed. Therefore, according to the present invention, even a material with extremely weak base material strength can be effectively impregnated with a liquid resin without damaging the base material form, and even a thick fiber base material can be effectively impregnated with a liquid resin. Since defoaming can be performed, it becomes possible to easily produce a prepreg sheet that does not contain air bubbles in the product.

Examples are illustrated below.

Example The following composition was used as the resin composition for impregnation.

Unsaturated polyester resin (for commercially available SMC, styrene content 40%) 100 parts by weight Benzoyl peroxide 2 parts by weight Magnesium oxide 1 part by weight As the fiber base material 14 for impregnation, commercially available glass chopped strand mat (300%
A commercially available double-sided release paper was used as the double-sided release paper 10.

First, after setting the double-sided release paper on the line, the clearance of the doctor knife 12 and back roll 13 is set to 0.
Adjusted to 71tm. The temperature of the doctor knife 12 and back roll 13 was adjusted to 30°C. Hot bed 2
The surface temperature of No. 3 was adjusted to 50°C. Next, while supplying the resin composition to the coater part, at the same time, the fiber base material 14 for impregnation is
was supplied. At this time, the line speed was adjusted to 2 m/min, and the reciprocating cycle of the movable impregnating roll was adjusted to 60 times/min. The comb-like impregnation roll used in this example had a comb pitch of 3.0? The depth of the can comb is 3.
0m3/f! } was used.

The prepreg sheet produced according to the above procedure is placed in a polyethylene bag or a container that can prevent styrene from scattering, and is aged in an oven at 50°C while rotating to B-stage, thereby eliminating air bubbles in the product. A semi-cured Bripreg sheet containing no resin was produced.

[Brief explanation of drawings]

Figure 1 is. An explanatory diagram showing an example of the conventional SMC manufacturing process, Fig. 2 is an explanatory diagram showing an example of the manufacturing process of the prepreg sheet according to the present invention, and Fig. 3 is an enlarged view of the impregnation roll part in Fig. 2. 4 is a plan view of a roll having a comb-shaped peripheral surface used in the present invention, and FIG.
The figure is an explanatory diagram showing the structure of a suction belt composed of a mesh belt and a suction box, and FIG. 6 is an explanatory diagram showing an enlarged view of the suction box in FIG. 5. 1, f...Polyethylene film. 2...Roping, 3,3''...Liquid resin composition, 4,4''...Doctor blade. 5... Chiyotsupa 1,. 6...Side shield, 7...Belt. ．． 8... Presser roll. 9... Winder Turret. 10...Double-sided release paper, 11...Liquid resin 612...Doctor knife. 13... Back roll 614... Fiber base material,
15... Roll for comb-like impregnation, 16... Support roll, 17... Roll for comb-like impregnation, 18... Mesh belt. 19...Guide roll, 20...
Suction box. 21...Final product. 22...Nipprol, 23...Hotbetsudo. 24...Suction hole.

Claims (1)

[Claims] 1. When manufacturing a prepreg sheet by impregnating a fiber base material with a liquid resin, the liquid resin is laminated on one side of a double-sided release sheet, and the fiber base material is layered on top of that to form a laminated sheet, and this laminated sheet is passed between a roll with a comb-like peripheral surface and two support rolls supporting this roll, the comb-like roll presses the fiber base material of the laminated sheet, and further, the laminate sheet is advanced. After pressing the fiber base material of the laminated sheet with a circumferential comb-shaped roll that reciprocates in the forward and reverse directions with respect to the direction, the fiber base material side is inside while pressing the other side of the double-sided release sheet of the laminated sheet with a nip roll. A method for producing a prepreg sheet, comprising: winding up the laminated sheet so that the laminated sheet becomes like this, and transporting the laminated sheet using a suction belt composed of a mesh belt and a suction box.