JPS6022607B2 - FRP molding method - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for molding FRP.

FR made by reinforcing resin with reinforcing fibers such as glass fiber
P (fiber reinforced resin) is well known.

Various methods are known for molding such FRP.

One such method is called resin injection. In the FRP molding method called resin injection, for example, glass cloth is placed on both sides of a glass strand mat or glass swirl mat, and the glass strand mat or glass swirl mat and glass cloth are molded into a desired shape using a pair of molds. The resin is held under molding pressure, and in this held state, a resin is press-fitted between a pair of molds, and then the resin is cured.

The FRP obtained in this case has a resin reinforced with a three-layer structure of glass cloth and glass strand mat or glass swirl mat and glass cloth. However, with such conventional methods, glass strand mats and glass swirl mats have low porosity, with an upper limit of about 85% at most, and glass swirl mats have uneven dispersion of the fibers that constitute them. Because the pore size is extremely large in some areas, it is difficult to disperse particularly high viscosity resin.
There is a drawback that it is difficult to mold FRP with uniform physical properties.

On the other hand, a method of forming FRP as described above by hand-laying is also known.

However, this method requires lamination of cloth or mats,
It is necessary to alternately repeat impregnating these with resin, which is time-consuming and has the drawback of low productivity. The purpose of the present invention is to solve the above-mentioned drawbacks of the conventional FRP molding method, to easily disperse even high viscosity resin, and to mold FRP with uniform physical properties with high productivity. The purpose of the present invention is to provide a method for molding FRP.

To achieve the above object, the present invention arranges a cloth material made of reinforcing fibers on at least one surface of a porous sheet, and then molds the porous sheet and cloth material into a desired shape using a pair of molds. A method for molding FRP in which the resin is held under pressure, and in such a held state, a resin is press-fitted between a pair of molds to impregnate the porous sheet and cloth-like material, and then the resin is cured. In this case, a net-like material is used as the porous sheet, and the net-like material of the bracket has legs extending in arbitrary three-dimensional directions and connecting portions that connect the legs to each other, and the legs between the adjacent connecting portions. The length of the part is 0.
The FRP molding method is characterized in that there are three or more ribs, and the total volume of the pores formed surrounded by the legs is 90% or more of the total volume of the mesh under the desired molding pressure. It is something to do.

The porous sheet referred to in the present invention is, for example, a foamed sheet of polyurethane resin, vinyl chloride resin, polyethylene resin, or epoxy resin, or a sheet formed by blending these resins with other substances and then forming the sheet with the other substances mentioned above. It can be obtained by dissolving and removing it, and an example is shown in FIG.

In FIG. 1 (schematic perspective view of main parts), "the porous sheet is a net-like material having leg portions 11 and connecting portions 12 that connect the leg portions 11 to each other.

The leg portion 11 extends in any three-dimensional direction, and a hole 13 is formed in a space surrounded by the leg portion 11. In the present invention, the length of the leg portion 11 of the net-like material as described above, that is, the length between two adjacent joint portions 12 is 0.3
The size of the pores 13 must be at least 90% of the total volume of the net when a desired molding pressure is applied to the sheet-like surface of the mesh. Leg length is 0.
If the total volume of the pores is less than 90% of the total volume of the net-like material when the desired molding pressure is applied to the sheet-like surface of the silk-like material, as described below. It becomes difficult to disperse the resin or the mixture of the resin and the microscopic hollow particles.
It becomes impossible to mold FRP with uniform physical properties. The reinforcing fiber cloth strip mentioned in the present invention is a woven fabric, knitted fabric, or mat made of high-strength, high-elasticity fiber such as carbon fiber, glass fiber, polyaramid fiber, silicon carbide fiber, or metal fiber. be.

Such a cloth material is disposed on one or both sides of the porous sheet, ie, on at least one side of the sheet. The resin used in the present invention is preferably a thermosetting resin such as an epoxy resin, an unsaturated polyester resin, or a polyimide resin, and a room temperature curing type.

For the purpose of reducing the weight of FRP and improving its strength against compressive loads, fine granular hollow bodies called feelers may be added to these resins. This filler is
For example, the average diameter of foamed inorganic materials such as quartz is 20.
It is a thin hollow body with a low specific gravity of ~300 (microns) and a volume ratio of 0.1 to 0. group added. In the present invention, a highly viscous mixture of such a resin and a feeler can also be used. next,
An embodiment of the FRP molding method of the present invention will be described.

In FIG. 2 (schematic longitudinal sectional view), a pair of molds consists of an upper mold 1 and a lower mold 2.

The pair of molds have surfaces facing each other. After applying a template agent such as polyvinyl alcohol or silicone grease to each of these opposing surfaces, the FRP is molded.
Gel coat layers 3 and 4 of epoxy resin are formed to smooth the surface. Next, a carbon fiber fabric 5 is laid as a reinforcing fiber sheet on the gel coat layer 4 of the lower mold 2, and a polyurethane resin foam sheet 6 is stacked thereon as a porous sheet.

Next, the carbon fiber fabric 7 is stacked on top of the foam sheet 6, and the upper mold 1 is placed on top of this, and then the bolts 8 are
, 9 to tighten the upper mold 1 and the lower mold 2. The tightening force is adjusted so that a predetermined molding pressure is applied to the carbon fiber fabrics 5 and 7 and the foam sheet 6. In this state, the total volume of the pores in the foam sheet 6 is 90% or more of the total volume of the foam sheet 6. On the other hand, the upper mold 1 is provided with a resin injection tube 10 whose injection port is open on the surface of the foam sheet 6, and a desired amount of the mixture of epoxy resin and filler is poured from this resin injection tube 10. 0
．． Press in with an air pressure of 5 to 10 (k9/k).

By this press-fitting, the mixture of the epoxy resin and the filler is impregnated into the carbon fiber fabrics 5 and 7 and the polyurethane foam sheet 6 through the pores of the foam sheet 6. At this time, the voids are expelled from the ends of the pair of molds into the outside air. After the epoxy resin is cured, it is removed from the mold to obtain an FRP having a three-layer structure of a carbon fiber fabric 5, a polyurethane resin foam sheet 6, and a carbon fiber fabric 7. As explained above, the FRP molding method of the present invention uses a net-like material as a porous sheet, and the net-like material of the parentheses has legs extending in arbitrary three-dimensional directions and joints that connect the legs to each other. The length of the legs between adjacent joints is 0.3 ribs or more, and the total volume of the holes surrounded by the legs is equal to or greater than the entire silk material under the desired molding pressure. 90% or more of the product, even highly viscous materials such as a mixture of resin and filler can be easily dispersed, making it an FRP with uniform physical properties.
Not only can it be molded, but it also eliminates the need to alternately repeat the process of laminating cloth or mats and impregnating them with resin, which is the case with conventional hand-laid methods, resulting in high productivity.

Further, by using a mixture of resin and filler, it is possible to obtain FRP that not only has uniform physical properties but also is lightweight and has high strength against compressive loads.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view showing the appearance of an example of a porous sheet used in the present invention, and FIG. 2 is a schematic longitudinal sectional view showing the FRP molding method of the present invention. 1: Upper mold of the mold, 2: Lower mold of the mold, 5, 7: Carbon delicate fabric (cloth-like material), 6: Polyurethane foam sheet (porous sheet), 11: Legs, 12: Joint part, 13:
Vacancy. Figure 1 Figure 2

Claims (1)

[Claims] 1 A fabric-like material made of reinforcing fibers is placed on at least one surface of a porous sheet, and then the porous sheet and the fabric-like material are held under a desired molding pressure by a pair of molds, and in such a held state, A method for molding FRP in which a resin is press-fitted between a pair of molds to impregnate the porous sheet and the fabric material, and then the resin is cured, the method comprising using a mesh material as the porous sheet. and this net-like material has legs extending in arbitrary three-dimensional directions and coupling parts that couple the legs to each other, and the length between adjacent coupling parts is 0.3 mm or more; A method for molding FRP, characterized in that the total volume of the pores formed by being surrounded by the parts is 90% or more of the total volume of the net-like material under the desired molding pressure.