JPS5811115A - Manufacture for frp with rib - Google Patents

Abstract

PURPOSE:To produce FRP having ribs without shrinkage by forming FRP under the condition in which one of sheet molding compounds defining an upper layer and a fower layer is colored and the boundary surface of both layers is caused to be as even as possible. CONSTITUTION:Sheet molding compound (under mention iSMC) composed of resin compound mixed together with 5-35mm. long glass fiber-bundle is placed on a female mold having concave gloove corresponding to the rib-part of FRP. On tnis compound, SMC composed of resin compound mixed together colorfully with 35-80mm. long glass fiber-bundle is put int piles. Then, SMC is hold compressibly between a male mold and a female mold and is heated, under the condition in which the boundary surface of SMC is caused to be as even as possible, thereby providing FRP with smooth surface. Further, when SMC-boundary surface has tendency to be uneven, it may be checked easily by optical method, because one of two layers is colored.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing an FR, P having a lip by using SMC (Sheet Molding Corner Land). The objective is to obtain FRP with a smooth surface.

SMC made of glass fiber bundles and thickened resin compositions is widely used when manufacturing various FRP products by press molding.

FftP by press molding using SMC as raw material
When manufacturing, for example, a predetermined amount of SMC is placed on a male mold, the female mold is lowered, and the SMC is heated while being compressed between the male and female molds. SMC flowed during this time.

Plastically deforms and fills the gap between both molds with SMC, bringing SMC into close contact with both mold surfaces.

The main components of S'MC are glass fiber bundles and liquid resin.

Regarding fillers and thickeners, when making SMC fluid, if the fluidity of the above-mentioned components differs greatly, it will not be possible to form a homogeneous product. Particularly when trying to manufacture large-sized FRP products, the fluidity of SMC is of great significance.

When manufacturing large and thin FRPM products, F'R
In order to give the P product the desired strength, it is necessary to reinforce it with a lip, but when a lip is provided, sink marks are likely to occur on the surface of the lip, making it impossible to obtain a smooth surface.

The reason for the occurrence of sink marks on the lip part is thought to be as follows. The isMc is pressed by the female mold and flows into the recess provided in the male mold to form a lip, but since glass fiber has poor fluidity compared to resin, the glass fibers above the lip flow into the lip. However, the glass fibers are not sufficiently supplied from the lip periphery, and the resin content increases near the top surface of the lip, and this area seems to have a large shrinkage rate when the resin hardens, causing sink marks. .

The fluidity of the glass fibers becomes better as the length of the glass fibers becomes shorter, but as the length of the glass fibers becomes shorter, the strength of the resulting product tends to decrease. In order to take advantage of these characteristics and prevent sink marks on the lip part, it has been proposed to bind the SMC in a two-layer structure and shorten the length of the glass fibers in the back layer of the SMC that contacts the male mold having four parts. .

When such a two-layer SMC is used, the glass fibers are supplied to the lip mainly from the back layer, and the fluidity of the glass fibers in the back layer is also good, which effectively prevents sink marks and improves the surface area. Since the layers can be composed of long glass fibers, the strength can be extended to thick FRP, and the two-layer structure of SMC is industrially useful.

The above-mentioned two-layer structure 8M (4-The molding method used is an effective method for preventing sink marks, but the SMC supply water place 1 heating temperature,
It has been found that product quality such as the presence or absence of sink marks and product yield vary considerably due to changes in working conditions such as the clamping force due to the heating time and the single mold.

Although working conditions are set to maximize the yield, there are cases where the operator is unaware that these conditions are changing during the work, resulting in a large number of defective products.

Furthermore, it is practical for SMC with a two-layer structure to manufacture each layer separately and stack them on a mold, but due to operator error, the order of stacking both layers was incorrect, and both layers used the same 5MCf: Defective products due to such accidental mistakes are not discovered during sampling inspections, and the defective products end up being mixed into the product.

As a result of various studies in order to solve these difficulties, the present inventor found that the SMC that constitutes the upper layer (surface layer) and the lower layer (back layer)
We have discovered that extremely favorable results can be obtained by coloring one of the layers and performing molding under conditions such that the interface between the SMC constituting both the upper and lower layers is as flat as possible, and we have proposed this as the present invention. This is what I did.

Why does the incidence of defective products decrease when molding is performed under conditions where the interface between both layers is flat? It was found that the incidence of defective products was significantly reduced compared to the previous model.

In the present invention, one of the upper and lower SMC layers is colored,
The other one is not colored. Therefore, if the boundary surface between both layers is not flat but uneven, in the case of a thin molded product, if you shine strong light from one side of the product and observe and measure the transmitted light from the other side, the unevenness can be seen as a difference in brightness and darkness. Since it is possible to understand the working conditions, it is extremely easy to manage the working conditions.

Furthermore, as the unevenness of the boundary surface becomes larger, the incidence of defective products increases. If the unevenness of the boundary surface is extremely large, for example, a colored pattern will appear on the back side of a product with a colored surface, or a non-colored pattern will appear on the surface of the product, so it is extremely easy to check. As mentioned above, the degree of unevenness on the boundary surface increases the incidence of non-defective products, so if an unevenness occurs on the boundary surface, check the working conditions and make sure the boundary surface is as flat as possible. . In addition to changing the work conditions, if the unevenness of the boundary surface exceeds a certain standard value, (1) increase the number of sample inspections.

(2) Perform a complete inspection.

(3) It is assumed that the product is defective.

By taking such measures, the rate of contamination of defective products can be greatly reduced.

Furthermore, in the present invention, the SMC of the surface layer and the SMC of the back layer
Since the two layers can be easily distinguished from each other in appearance 2, it is possible to eliminate the occurrence of work errors due to confusion between the two layers.

Furthermore, by making the surface layer a color that is as inconspicuous as the color of the product's paint, it is possible to reduce appearance defects when the paint film peels off during use.

Next, the present invention will be explained in more detail.

A sizing agent is added to the glass fibers pulled out from the bushing to form a glass fiber bundle. In the present invention, suitable results were obtained by using the following glass fiber bundles.

(1) Glass fiber thickness: 9 to 20μ (2) Number of bundled fibers: 50 to 400 (3) Type of sizing agent: polyester, vinyl acetate, or epoxy (4) Amount of sizing agent added: Solid 0 for glass fiber as a minute
．． A 5-2wt glass fiber bundle cut into a length of 35-35 cm (referred to as long C8) was used to form the surface layer SMC, and the glass fiber bundle was cut into a length of 5-35 cm. (shortly referred to as C8) is used to manufacture the SMC of the back layer. Furthermore, SMC
Since a conventional method can be used for manufacturing, no particular explanation will be given.

SMCs constituting the front and back layers are suitable to have the following specifications.

13 Surface layer (1) Length of C8 35-80 Long (2) Amount of C8O (weight ratio of CS in SMC) 30-4
5Wt Chi (3) Type of resin: unsaturated polyester resin, phenol resin, vinyl ester resin (4) Amount of resin (weight ratio of resin in SMC) 20-3
5wt% (5) Type of thickener: magnesium hydroxide, magnesium oxide, calcium hydroxide, calcium oxide,
Amount of isocyanate (6) thickener (weight ratio of thickener in resin composition)
0.1-1wt% (Power) Type of colorant: Carbon, iron oxide, inorganic pigment such as chrome yellow, or organic pigment (8) Amount of colorant (weight percentage of colorant in resin composition)
0.1-3wt% ■, Back layer (1) Length of C8 5-35 Dragon (2) Amount of csO (weight ratio of CS in SMC) 15-3
0wt% (3) Type of resin: unsaturated polyester resin, phenol resin, vinyl ester resin (4) Amount of resin (weight ratio of resin in SMC) 20-3
5wt% (5) Type of thickener: magnesium hydroxide, magnesium oxide, calcium hydroxide, calcium oxide,
Amount of isocyanate (6) thickener (weight ratio of thickener in resin composition)
0.1-1wt% (Power) Type of colorant: Carbon, iron oxide, inorganic pigment such as chrome yellow, or organic pigment (8) Amount of colorant (weight percentage of colorant in resin composition)
0.1-3wt% Calcium carbonate, clay, aluminum hydroxide,
It is appropriate to use a resin premixed with a filler such as zinc borate.

The type and amount of resin in the SMC of the surface layer and the back layer are substantially the same, and the amount of filler in the SMC of the back layer is 1.1-1.6. It has been found that a more uniform product can be obtained by approximately doubling the amount.

Place the uncolored SMC containing the short C8′f described above on a female mold having a groove corresponding to the lip portion, overlay the colored isMC containing the long C8 on top of this, and lower the female mold,
Press and heat with both male and female molds.

Normal clamping force is 20~140 kglcr&, lowering speed of female mold is 0.5/16 dragon/nose, heating temperature is 130~170
C1 heating time is about 1 to 4 minutes, but the degree of unevenness of the interface between both layers varies depending on changes in these working conditions. In the present invention, working conditions are determined experimentally to make the interface between both layers as flat as possible.

Here, "as flat as possible" means that when the average thickness of the colored layer is 1, the width of thickness variation is within ±25%, preferably 15%.
It means that it is within. In this state, the boundary surface is substantially parallel to the surface layer and has substantially no irregularities. In addition, when cutting and removing the end portion of the molded product, the above conditions shall be determined excluding this end portion.

The thickness of the surface layer and back layer (X number per layer) is determined depending on the desired product thickness and the size and number of lips and bosses, but the ratio of the two is l: 0.3 to 1: 5. It is appropriate that the length ratio of the long glass fiber bundle to the short glass fiber bundle is about 2 to 8:l.

Claims (1)

[Claims] SM consisting of short glass fiber bundles and thickened resin composition
C, a long glass fiber bundle, a thickened resin composition, and an SMC are layered on the lower mold in such order that the former is in contact with the mold having the concave groove, and one of both SMC is colored, and both SM
FRP with a lip characterized by heating while being compressed with an upper die under conditions such that the boundary surface of C is as flat as possible.
manufacturing method.