JPH10211660A - Frp molded product and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing an FRP molded product wherein defoaming process is eliminated, by reducing the mixing of air bubbles in an intermediate layer itself and increasing the thickness of the intermediate layer to reduce the effect of a fiber reinforced layer on a gel coat layer, and to provide an FRP molded product. SOLUTION: A gel coat layer is formed on the surface of a mold and an intermediate layer is formed on the surface of the gel coat layer and a fiber reinforced layer is formed on the surface of the intermediate layer. In a method for producing an FRP molded product by a spray-up method, when the intermediate layer is formed, staple fibers having average fiber length shorter than that of fibers used in the fiber reinforced layer and a reaction curable resin containing a granular lightweight filler are individually sprayed on a gel coat layer as a coating material or mixed to be sprayed thereon.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for forming a gel coat layer on the surface of a mold, forming an intermediate layer on the surface of the gel coat layer, and forming a fiber reinforced layer on the surface of the intermediate layer.
The present invention relates to a method for producing an FRP (fiber reinforced resin) molded product by a spray-up method, and an FRP molded product that can be produced by the production method.

[0002]

2. Description of the Related Art Conventionally, bath tubs, septic tanks, waterproof pans for bathrooms, etc. have been manufactured as FRP molded articles by various manufacturing methods. However, the spray-up method is used because of the low equipment cost and the ability to cope with complicated shapes. Is widely used. When a molded article having a laminate structure is manufactured by such a spray-up method, a gel coat layer mainly composed of a reactive curable resin and a pigment is formed on the surface of a previously prepared mold, and the reactive curable resin is formed on the surface of the gel coat layer. And a step of forming a fiber reinforced layer mainly composed of fibers. At that time, bubbles are easily mixed into the formed fiber reinforced layer, and swelling and cracks are easily generated on the surface of the gel coat layer after molding due to the influence of the bubbles in the fiber reinforced layer. A defoaming step of removing bubbles using a defoaming roll or the like has been performed.

In order to improve the influence of air bubbles in the fiber reinforced layer, Japanese Patent Publication No. 5-24833 discloses a first laminate layer (intermediate layer) having a predetermined thickness composed of a relatively short reinforcing fiber and a thermosetting resin. ) Between the gel coat layer and the second laminate layer (fiber reinforced layer). Then, the formation of the first laminate layer is performed by a spray-up method, and when the defoaming step of the first laminate layer is performed according to the length of the reinforcing fiber (6 mm).
Above) or not (6 mm or less).

[0004]

However, in the method of using a relatively short reinforcing fiber for the intermediate layer as described above,
Since the length of the reinforcing fiber is small, there is a problem that the liquid is easily dripped and the thickness of the intermediate layer cannot be increased. As a result, even if the intermediate layer is provided, the effect of the fiber reinforced layer on the gel coat layer is likely to occur, and the defoaming step of the fiber reinforced layer is still required.

On the other hand, there is a method of adding various additives without using reinforcing fibers in the intermediate layer (for example, JP-A-6-305035). However, since no reinforcing fibers are used in the intermediate layer, dripping occurs. This is problematic in that the thickness of the intermediate layer cannot easily be increased, bubbles in the fiber reinforced layer may migrate to the intermediate layer during curing, and the strength after curing is not sufficient. As a result, even if the intermediate layer is provided, the effect of the fiber reinforced layer on the gel coat layer is likely to occur, and a defoaming step of the fiber reinforced layer is required unless a specific resin composition is used.

[0006] An object of the present invention is to solve the above-mentioned problems by reducing the incorporation of bubbles into the intermediate layer itself and increasing the thickness of the intermediate layer to reduce the influence of the fiber reinforced layer on the gel coat layer. Accordingly, it is an object of the present invention to provide a method of manufacturing an FRP molded article and an FRP molded article that do not require a defoaming step.

[0007]

Means for Solving the Problems In order to achieve this object, the present inventors have conducted intensive studies on the use of various additives and the composition and thickness of each layer. The inventors have found that the above object can be achieved by spraying a short fiber and a reactive curable resin containing a granular light filler as a coating material, and have completed the present invention.

That is, the characteristic structure of the method for producing an FRP molded product of the present invention is that a gel coat layer is formed on the surface of a mold, an intermediate layer is formed on the surface of the gel coat layer, and fiber reinforced is formed on the surface of the intermediate layer. Forming a layer, in the method for producing an FRP molded product by a spray-up method, when forming the intermediate layer, a short fiber having an average fiber length shorter than the fiber used in the fiber reinforced layer, and a granular lightweight filler The reaction curable resin contained therein is sprayed onto the gel coat layer individually or as a mixture as a coating material.

In the above structure, the average fiber length of the short fibers may be shorter than the fibers used in the fiber reinforced layer, and can be appropriately set according to the type and amount of the fibers. Is preferable from the operation and effect described below.

The amount of the granular lightweight filler used may be an amount capable of exhibiting the effect of preventing dripping, and may be appropriately set depending on the type and amount of the lightweight filler, the type of the short fiber and the resin, and the like. Although it is possible, the amount is preferably 20 to 30 parts by weight with respect to 100 parts by weight of the reaction curable resin from the viewpoint of the operation and effect described later.

Further, the average thickness of the intermediate layer may be set in consideration of the influence of the fiber reinforced layer on the gel coat layer, its strength, etc., but it is preferably 1.0 to 4.0 mm after curing. It is preferable from the operation and effect described below.

On the other hand, the FRP molded article of the present invention is characterized by a gel coat layer mainly composed of a reaction curable resin and a pigment, an intermediate layer formed on the surface thereof and composed mainly of a reaction curable resin, In a FRP molded article having a fiber-reinforced layer mainly composed of a reaction-curable resin and fibers, the intermediate layer has a short fiber having an average fiber length shorter than that of the fiber contained in the fiber-reinforced layer; And a lightweight filler.

According to the method for producing an FRP molded article of the present invention, when forming the intermediate layer, short fibers having an average fiber length shorter than the fibers used in the fiber reinforced layer are provided; By spraying the curable resin containing the granular lightweight filler with the gel coat layer individually or as a coating material, and mixing the foam with the intermediate layer itself as shown in the results of Examples described later. By reducing the influence of the fiber reinforced layer on the gel coat layer by increasing the thickness of the intermediate layer and reducing the thickness, the defoaming step could be made unnecessary. Note that, with such a configuration, the effect as described above is obtained because if only short fibers are added in a usage amount that does not cause air bubbles to mix, dripping easily occurs due to low viscosity and the thickness of the intermediate layer cannot be increased, but granular By using the lightweight filler, in addition to the thickening effect is obtained, short fibers can be easily adapted to the resin and the total amount of the short fibers and the lightweight filler can be increased, so that dripping can be effectively prevented, and as a result,
It is considered that since the thickness of the intermediate layer can be increased, its strength can be further increased and the influence of the fiber reinforced layer on the gel coat layer can be reduced.

When the average fiber length of the short fibers is 2 to 8 mm, fiber cutting by the apparatus is easier, and air bubbles are hardly mixed into the intermediate layer even at the bent portion of the molded product.

When the amount of the particulate lightweight filler used is 20 to 30 parts by weight with respect to 100 parts by weight of the reaction curable resin, dripping can be effectively prevented and bubbles are mixed into the intermediate layer. Hard to do.

The intermediate layer has an average thickness of 1.0 after curing.
When the thickness is 4.0 mm, the influence of the fiber reinforced layer on the gel coat layer can be reduced, and necessary and sufficient strength can be provided.

On the other hand, according to the FRP molded article of the present invention, the thickness of the intermediate layer can be increased for the same reason as described above, so that the strength can be further increased and the influence of the fiber reinforced layer on the gel coat layer can be reduced. .

[0018]

Embodiments of the present invention will be described below. The method for producing an FRP molded product according to the present invention is a spray-up method comprising: forming a gel coat layer on the surface of a mold, forming an intermediate layer on the surface of the gel coat layer, and forming a fiber reinforced layer on the surface of the intermediate layer. In the method for producing an FRP molded product according to the above, when forming the intermediate layer, a short fiber having an average fiber length shorter than the fiber used in the fiber reinforced layer, and a reactive curable resin containing a granular lightweight filler And spraying the gel coat layer individually or in combination as a coating material. Therefore,
The steps other than the step of forming the intermediate layer are not particularly limited, and generally known steps can be employed. Hereinafter, each step will be described in order.

[Step of Forming Gel Coat Layer] The gel coat layer is formed by a known material / method mainly for the purpose of forming an aesthetically pleasing surface and preventing water leakage. The outline of this step is to form a gel coat layer by applying a coating material mainly containing a reaction curable resin and a pigment by spraying or brush coating on a surface of a mold such as a mold and a resin mold, When the next step is performed after the resin is cured, the resin is cured after the application. As the reaction curable resin, an unsaturated polyester resin, a vinyl ester resin, an epoxy resin or the like is used. In addition to pigments, additives such as thickeners can be used. The average thickness of the gel coat layer is about 0.2 to 0.5 mm after curing, preferably 0.3 to 0.4 m.
m.

[Step of Forming Intermediate Layer] The step of forming the intermediate layer comprises, when forming the intermediate layer, short fibers having an average fiber length shorter than the fibers used in the fiber reinforced layer, and a granular lightweight filler. A reaction curable resin is sprayed on the gel coat layer individually or mixed as a coating material.

Examples of the type of the short fiber include glass fiber and those obtained by performing various surface treatments on the fiber, but any fiber having the same physical properties can be used. The average fiber length of short fibers is
It is preferably 2 to 8 mm, more preferably 3 to 8 mm.
6 mm, most preferably about 4 mm. The amount of the short fiber used depends on the type of the resin used and the amount of the lightweight filler, but is preferably 10 to 25% by weight, more preferably 15 to 20% by weight, based on the total weight of the intermediate layer. If the thickness exceeds this range, the thickness of the layer tends to be increased, but air bubbles tend to remain. If the thickness is less than this range, dripping tends to occur and the thickness of the layer tends to be hard to increase.

As the type of the granular lightweight filler, a hollow inorganic material or a resin material can be used, but a spherical hollow body is preferably used. Specifically, shirasu balloon, ceramic balloon, glass balloon, silica balloon, carbon balloon, phenol balloon, alumina balloon and the like are used. Above all, a shirasu balloon is preferably used in the present invention because it is inexpensive and has good compatibility with resins and fibers. The particle diameter of the lightweight filler is preferably an average particle diameter of 10 to 300 μm,
It is more preferably from 30 to 200 μm, most preferably about 100 μm. If it exceeds this range, the affinity with the resin and the fiber tends to be poor.

For the reasons described above, the amount of the particulate lightweight filler used is 20 to 100 parts by weight of the reaction curable resin.
It is preferably 30 parts by weight, but about 10 to 40 parts by weight can also be used depending on the type of resin used and the amount of short fibers.

Examples of the reactive curable resin include those containing a resin component such as an unsaturated polyester resin, a vinyl ester resin and an epoxy resin, and a monomer component such as a styrene monomer and an acrylic monomer. The viscosity of such a reaction curable resin can be adjusted by adjusting the amount of the monomer component, but after mixing the lightweight filler, 14 to 2 times.
It is preferably adjusted to 0 poise, more preferably 16 poise.
~ 18 poise. If it exceeds this range, it will tend to be less compatible with the resin and the fibers, and if it is less than this range, it will be easy for liquid to drool and the thickness of the layer will not be easily obtained.

The above coating materials are sprayed onto the gel coat layer individually or in a mixture. The method of spraying the short fibers and the resin composition simultaneously from separately provided nozzles is as follows.
It is preferable without the influence of thickening or the like due to premixing of short fibers. That is, in the method of mixing and spraying in advance, there is a problem such as clogging of nozzles. For example, nozzles are individually provided and mixed immediately after spraying from the nozzles, and the mixture is applied to the coating surface in the mixed state. And other methods. The average thickness of the intermediate layer obtained above is preferably from 1.0 to 4.0 mm after curing for the reasons described above, and is preferably from 1.5 to 4.0 mm.
It is more preferable that the thickness be 2.0 mm, because the effect of the fiber reinforced layer on the gel coat layer can be reduced while imparting sufficient strength.

[Process of Forming Fiber Reinforced Layer] The fiber reinforced layer is formed mainly for the purpose of increasing the overall strength of the FRP molded product.
It is performed by a known material and method. The outline of this step is to form a fiber reinforced layer by applying a coating material mainly composed of a reaction-curable resin and fibers to the surface of the intermediate layer by spraying or the like, and the resin is cured after the application.

Examples of the type of fiber include glass fiber and those obtained by subjecting the fiber to various surface treatments, and any fiber having similar physical properties can be used. The average fiber length of the fibers is preferably from 15 to 50 mm, more preferably from 25 to 30 mm. If it exceeds this range, fluffing tends to increase, and if it is less than this range, the reinforcing effect tends to decrease. The amount of the fiber used depends on the type of resin used, but is preferably 30 to 40% by weight based on the total weight of the fiber reinforced layer from the viewpoint of the strength of the fiber reinforced layer.

Examples of the reactive curable resin include those containing a resin component such as an unsaturated polyester resin, a vinyl ester resin, and an epoxy resin, and a monomer component such as a styrene monomer and an acrylic monomer. The viscosity of such a reaction curable resin can be adjusted by the amount of the monomer component.

The above-mentioned coating material is sprayed on the intermediate layer in the same manner as in the above-mentioned step of forming the intermediate layer. The average thickness of the obtained fiber reinforced layer is preferably about 2 to 3 mm after curing.

[FRP molded article] The FRP molded article of the present invention comprises a gel coat layer mainly composed of a reaction curable resin and a pigment, an intermediate layer formed on the surface thereof and composed mainly of a reaction curable resin, and a surface thereof. A FRP molded article having a fiber-reinforced layer mainly composed of a reaction-curable resin and a fiber, wherein the intermediate layer has a short fiber having an average fiber length shorter than the fiber contained in the fiber-reinforced layer. , And a granular lightweight filler. Such an FRP molded product is suitably produced by the production method of the present invention. Therefore, the types and compositions of various materials, the thicknesses of the layers, and the like are as described above. The FRP molded product of the present invention is used for applications such as bathtubs, septic tanks, waterproof pans for bathrooms, etc., and the shape of the mold is determined according to the shapes thereof.

[0031]

EXAMPLES Specific examples and comparative examples for confirming the effects of the present invention will be shown below, but the present invention is not limited to these examples.

Example 1 Under the following conditions, a gel coat layer, an intermediate layer and a fiber reinforced layer were formed on a resin mold for a waterproof pan for a bathroom by a spray-up method, and cured and released without any defoaming. The surface of the gel coat layer was visually evaluated. In addition, when the intermediate layer was formed, the dripping of the coating material on the vertical surface was visually evaluated.

[Step of Forming Gel Coat Layer] Reaction curable resin: gel coat (M3, manufactured by Mikuni Color Co., Ltd.)
370) Average thickness of gel coat layer: 0.4 mm after curing [Step of forming intermediate layer] Type of short fiber: glass fiber (GR manufactured by Nippon Sheet Glass Co., Ltd.)
27) Average fiber length of short fibers: about 4 mm Amount of short fibers used: 17% by weight Type of lightweight filler: Shirasu balloon (Silax Corporation, PB-03) Particle diameter of lightweight filler: 100 μm (average particle diameter) Amount of lightweight filler used: 25 parts by weight (based on resin: 100 parts by weight) Reaction curable resin: unsaturated polyester resin (5139, manufactured by Nippon Yupika Co., Ltd.) Monomer: styrene Average thickness of intermediate layer: 1.7 mm [fiber Forming Step of Reinforcing Layer] Average fiber length of fiber: about 30 mm Fiber usage amount: 30% by weight based on total weight Reaction curable resin: Unsaturated polyester resin (5139, manufactured by Nippon Yupika Co., Ltd.) Average thickness of fiber reinforcing layer Sa: 2.5 mm after curing The results are shown in Table 1.

Example 2 In Example 1, except that the kind of the lightweight filler was changed to a glass balloon (Z-27, manufactured by Asahi Glass Co., Ltd.),
Each layer was formed in the same manner as in Example 1. Table 1 shows the results.

Example 3 In Example 1, the particle size of the lightweight filler was 40 μm.
Each layer was formed in the same manner as in Example 1 except that the average particle diameter was changed. Table 1 shows the results.

Comparative Example 1 Each layer was formed in the same manner as in Example 1 except that the lightweight filler was not used for forming the intermediate layer. Table 1 shows the results.

Comparative Example 2 Each layer was formed in the same manner as in Example 1 except that the lightweight filler was not used for forming the intermediate layer and that the coating thickness of the intermediate layer was reduced to half. Table 1 shows the results.

[0038]

[Table 1]

As shown in the results of Table 1, in each of the examples, the air bubbles were not mixed into the intermediate layer itself, and the influence of the fiber reinforced layer on the gel coat layer was reduced, so that the defoaming step was not performed. An RP molded product having good surface smoothness was manufactured.
On the other hand, in Comparative Example 1 in which the lightweight filler was not used to form the intermediate layer, the intermediate layer was dripped and the thickness of the intermediate layer could not be increased, and Comparative Example 2 in which the intermediate layer was thinner The surface smoothness was not good due to the influence of bubbles in the fiber reinforced layer.

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Claims (5)

[Claims] 1. A gel coat layer is formed on a surface of a mold,
A method for producing an FRP molded product by a spray-up method, wherein an intermediate layer is formed on the surface of the gel coat layer, and a fiber reinforced layer is formed on the surface of the intermediate layer. Spraying short fibers having an average fiber length shorter than the fibers used in the reinforcing layer and a reactive curable resin containing a granular light filler individually or mixed as a coating material onto the gel coat layer
Manufacturing method of RP molded product. 2. An average fiber length of the short fibers is 2 to 8 mm.
The method for producing an FRP molded product according to claim 1, wherein 3. The method for producing an FRP molded product according to claim 1, wherein an amount of the granular lightweight filler used is 20 to 30 parts by weight based on 100 parts by weight of the reaction curable resin. 4. The method according to claim 1, wherein the intermediate layer has an average thickness of 1.
The FR according to any one of claims 1 to 3, which has a thickness of 0 to 4.0 mm.
Manufacturing method of P molded product. 5. A gel coat layer mainly composed of a reaction-curable resin and a pigment, an intermediate layer formed on the surface thereof and composed mainly of a reaction-curable resin, and a gel coat layer mainly composed of a reaction curable resin and fibers formed on the surface thereof. An FRP molded article having a fiber reinforced layer as a material, wherein the intermediate layer contains short fibers having an average fiber length shorter than the fibers contained in the fiber reinforced layer, and a particulate lightweight filler. Goods.