JPH1158537A - Manufacture of frp molded article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the strength decrease, and improve the surface smoothness and the gloss by a method wherein on at least one part of the internal surface of dies for molding, a gel coated layer is formed, and then, in the dies, a bulk molding compound material containing a recycling FRP powder, is arranged, and a forming is performed by heating and pressurizing. SOLUTION: After forming a gel coated layer on at least one part of the internal surface of dies for molding, a bulk molding compound(BMC) material containing a recycling FRP powder is arranged in the dies, and a forming is performed by heating and pressurizing. Therefore, the gel coated layer is formed on the surface of an FRP molded article containing the recycling powder by the heating-pressurizing forming, and the gel coated layer prevents the surface characteristics from deteriorating due to the recycling powder, and the surface smoothness and the gloss are improved. Also, even when a reinforcing fiber contained in the recycling FRP powder is slightly short, the strength of the obtained FRP molded article can be made hard to decrease, and a larger amount of the recycling FRP powder can be contained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a recycled FRP.
The present invention relates to a method for producing an FRP molded product in which a bulk molding compound (hereinafter abbreviated as “BMC”) is molded using powder.

[0002]

2. Description of the Related Art Conventionally, as a method of recycling an FRP molded article, a method of manufacturing an SMC molded article by using a recycled FRP powder from an SMC molded article, a method of recycling an FRP powder from a molded article by spraying-up, etc. A method for producing a molded article by spraying up using
There has been known a method of recycling finely ground recycled FRP powder as a filler.

The above-mentioned method is disclosed in, for example,
No. 112500 discloses that recycled FR is provided on both surfaces of a first layer containing recycled FRP powder from SMC molded products.
By forming the second layer containing no P powder, SM
Techniques have been proposed to reduce a decrease in bending elastic modulus and bending strength of a C molded product. As the above method, for example, JP-A-8-11211 discloses that the surface of the gel coat layer is
A technique has been proposed in which a backup layer containing recycled FRP powder is formed by spray-up. As the above method, for example, Japanese Patent Application Laid-Open No. Hei 5-309753 proposes a technique of recycling recycled FRP powder finely pulverized to 100 μm or less as a filler.

[0004]

However, in the above and the above-mentioned recycling methods, the waste FRP
When a molded product is recycled into an SMC molded product or a spray-up molded product, the reinforcing fibers contained in the molded product are inevitably shortened due to pulverization or the like, so that a decrease in the strength of the molded product is inevitable. That is, a reinforcing fiber having a length of 10 mm or more is usually used for an SMC molded product or a spray-up molded product, but when crushed to a recyclable size, the recycled powder is contained at the time of crushing. The length of the fiber becomes very short (about 2mm at most), SM
The reinforcing effect on the C molded product and the spray-up molded product cannot be expected much. Therefore, in the above, the decrease in strength is reduced by adopting a sandwich structure, and the reinforcing effect is considered to be small because the recycled powder ground to 20 to 200 μm is used in the above.

[0005] On the other hand, in the above-mentioned method, it is not clear what type of molded article is recycled.
Since there is a statement that fibers with a size of 00 μm or more have been removed, it is not expected that the fibers contained in the recycled powder have a reinforcing effect. Instead, recycled powder is used as a substitute for a simple filler (such as calcium carbonate). It is clear that it is used.

[0006] In other words, the conventional methods have problems in practicality, such as the strength of the FRP molded product obtained by recycling is easily reduced, and it is necessary to make the structure to compensate for the reduced strength. Was.

On the other hand, FRP molded products obtained by recycling are known to have inferior surface smoothness and gloss, and in particular, when performing BMC molding, the difference from the case without recycling is remarkable. In the above-mentioned technology, there has been proposed a method in which a backup layer containing recycled FRP powder is formed on a surface of a gel coat layer by spraying up. However, there has been no example in which a BMC molded product has been recycled. Therefore, in BMC molding, it was unknown to those skilled in the art how much the effect of improving the surface properties by the gel coat layer was.

[0008] Accordingly, an object of the present invention is to provide a method for producing an FRP molded article which can obtain an FRP molded article having good surface smoothness and gloss, can reduce the strength reduction, and can increase the content of recycled powder. Is to provide.

[0009]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies in order to achieve this object. As a result, by providing a gel coat layer in BMC molding, FRP molding with good surface smoothness and gloss was achieved. The present inventors have found that a product can be obtained, and further studied a method of forming a gel coat layer, and have completed the present invention. That is, the characteristic configuration of the manufacturing method of the FRP molded product of the present invention is that after forming a gel coat layer on at least a part of the inner surface of the molding die,
The point is that a bulk molding compound (BMC) material containing recycled FRP powder is placed, and the molding is performed by applying heat and pressure.

In the above structure, the recycled FRP
The powder is a sheet molding compound (SM
C) It is more preferable to be recycled from an FRP molded product formed by spray-up or hand lay-up than the operation and effect described below.

[Effects] According to the above-mentioned characteristic configuration, as shown in the results of the examples described later, the gel coat layer formed on the inner surface of the molding die forms the recycled powder by heat and pressure molding. It is formed on the surface of the FRP molded product containing it, and prevents the deterioration of the surface characteristics due to the recycled powder, so that an FRP molded product having good surface smoothness and gloss can be obtained. In BMC molding, usually, relatively short reinforcing fibers are used, so that even if the reinforcing fibers contained in the recycled FRP powder are somewhat short, it is possible to make it difficult to reduce the strength of the obtained FRP molded product. it can. In addition, since the deterioration of the surface characteristics is small as described above,
A larger amount of recycled FRP powder can be contained, and the effect on the global environment is great. The reason why relatively short reinforcing fibers are used in the FRP molding material composition for BMC molding is that a certain degree of fluidity is required after mixing the reinforcing fibers. As a result, it is possible to obtain an FRP molded product having good surface smoothness and gloss, and furthermore, it is possible to reduce strength reduction and increase the content of recycled powder.
A method for producing an RP molded article can be provided.

[0012] The recycled FRP powder is used for sheet molding compound (SMC), spray up,
Or when it is recycled from the FRP molded product molded by hand lay-up, especially, it becomes easy to include the reinforcing fiber having a length suitable for BMC molding in the recycled FRP powder, so that the strength reduction is more reduced. Can be reduced and the content of recycled powder can be increased. At that time, since the length of the reinforcing fiber included is relatively long, the surface characteristics of the FRP molded product are more likely to be impaired due to the influence thereof, but the effect of the gel coat layer as described above makes it effective. Can be improved.

[0013]

Embodiments of the present invention will be described below in detail.

According to the method of manufacturing an FRP molded article of the present invention, after forming a gel coat layer on at least a part of the inner surface of a molding die, a BMC material containing recycled FRP powder is placed in the die. Then, molding is performed by applying heat and pressure.

First, B containing recycled FRP powder
The MC material will be described. BMC used in the present invention
The material is not different from ordinary BMC materials except that it contains recycled FRP powder. For components and content other than recycled FRP powder, thermosetting resins, fillers, Any of a low shrinkage agent, a curing agent, an internal release agent, a pigment, various additives, and the like can be used in the present invention.

As the recycled FRP powder, a sheet molding compound (SM)
C) Recycled from an FRP molded product formed by spray-up or hand lay-up is preferably used, but the recycled FRP powder is too large and does not hinder mixing of materials or molding. As described above, it is preferable that the recycled FRP powder is classified into 10 mesh under after crushing. Such a recycled FRP powder contains a granular material and a fiber, and substantially contains a fiber having a fiber length of 1 mm or more from the viewpoint of containing a reinforcing fiber having a length in a preferable range for BMC molding. It is particularly preferable that the fibers mainly contain fibers having a fiber length of 1 mm or more.

The recycled FRP powder increases the amount of flexure at the time of bending fracture and improves the impact resistance. Therefore, the FRP molding material composition contains 20 to 70% by weight, particularly 30 to 60% by weight. % Is preferably contained.

The recycled FRP powder is obtained by first crushing an FRP molded product formed by sheet molding compound (SMC), spray-up, or hand lay-up into a 200 to 400 mm square FRP piece by a crusher or the like, and crushing the same. For example, 20
It can be obtained by crushing FRP pieces of mm square, further crushing with a fine crusher or the like, and then classifying with a vibrating screen or the like as described above.

Examples of the thermosetting resin include unsaturated polyester resin, epoxy resin, vinyl ester resin, and acrylic resin. However, since the reaction curability, viscosity before curing, etc. are suitable for BMC molding, unsaturated resins are used. Polyester resins are particularly preferably used. In addition, since the affinity between the resins is improved, and the dispersibility at the time of mixing and the strength after molding are improved, the recycled FRP powder contains the same type of thermosetting resin as the thermosetting resin blended. It is preferable that

As the unsaturated polyester, those having an ester bond and an unsaturated bond in the main chain may be used, and any of ortho-type, iso-type, tele-type, bis-type and halogen-type can be used. Unsaturated polyester is
Usually, it is produced by polycondensation using an acid component such as an unsaturated dibasic acid or an acid anhydride thereof and an alcohol component such as glycol. As the above acid component, a saturated dibasic acid or the like may be used in combination.For example, fumaric acid, itaconic acid, maleic anhydride and the like are unsaturated components, and isophthalic acid, adipic acid, sebacic acid, phthalic anhydride and the like. Used as a saturated component. As the alcohol component, ethylene glycol, propylene glycol, diethylene glycol, bisphenol dihydroxypropyl ether and the like are used.

As a curing agent for the unsaturated polyester, for example, an organic peroxide is used, and its chemical structure is ketone peroxide, hydroperoxide, diacyl peroxide, dialkyl peroxide, peroxyketal, alkyl perester, or the like. It is classified and used as percarbonate. In addition, as a vinyl monomer for forming a three-dimensional structure (chain-extending monomer),
Styrene, vinyl toluene, methyl methacrylate and the like are used. In addition, various polymerization catalysts, various polymerization initiators, chain-extending monomers, and the like are used for other thermosetting resins.

The content of the reinforcing fiber can be reduced by the reinforcing effect of the above-mentioned recycled powder, and depending on the required performance, it is not necessary to add a new reinforcing fiber. As the reinforcing fiber, an inorganic fiber such as a glass fiber or a ceramic fiber, an organic fiber such as a high elastic polymer fiber, or the like is used. The length of the fiber is preferably about 1 to 6 mm.

As the filler is considerably contained in the recycled powder, its content can be reduced, and depending on the required performance, it is not necessary to add a new filler. As the filler, inorganic fillers such as glass powder, calcium carbonate, alumina, aluminum hydroxide, barium sulfate, talc, and clay, and organic fillers such as various elastomers are used. Polystyrene, polyethylene, styrene / vinyl acetate copolymer and the like are used as the low shrinkage agent. As the internal release agent, fatty acid metal salts such as zinc stearate and calcium stearate are used. As the pigment, an organic pigment such as an azo pigment or a copper phthalocyanine pigment, or an inorganic pigment such as titanium oxide or red iron oxide is used. When arranging the BMC material, if it is necessary to increase the viscosity, a thickener such as magnesium hydroxide or calcium hydroxide is used. The BMC material can be obtained by mixing and stirring the above components with a biaxial kneader or the like.

Next, each step will be described. In the present invention, a gel coat layer is first formed on at least a part of the inner surface of a molding die. The gel coat layer is formed on a portion where surface characteristics are required, and is usually formed on a visible portion of various molded articles such as a surface portion of a bathtub, but may be formed entirely. Therefore, of the entire molding die,
The gel coat layer is formed over any one of the molds (for example, a lower mold) or a plurality of molds.

The gel coat layer is formed by spraying a gel coat material onto the inner surface of a molding die and subjecting the applied gel coat layer to the next step in an uncured state or after curing. .

As the material for forming the gel coat layer, the above-described thermosetting resin and components for curing the same, ie, various polymerization catalysts, various polymerization initiators, chain-extending monomers, and the like are used. Among them, unsaturated polyester resins and components for curing the same, that is, vinyl monomers such as styrene monomers and various curing agents are preferably used. In addition, materials for forming the gel coat layer include, in addition, inorganic powders such as fine powder silica and calcium carbonate for imparting appropriate viscosity and thixotropy to the gel coat for sagging prevention, and inorganic hydroxides such as aluminum hydroxide. Used.

In the present invention, in order to improve the surface characteristics of the FRP molded product, the thickness of the formed gel coat layer is preferably 0.1 to 2 mm, more preferably 0.5 to 1.5 mm.

In the present invention, subsequently, the above-mentioned BMC material containing the recycled FRP powder is placed in a mold, and the molding is performed by heating and pressing. In arranging the BMC material, thickening, shaping, aging and the like are performed as necessary. The conditions for heating and pressing, the type of the press device, the type of the die, and the like can be set according to ordinary BMC molding.

[0029]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments and the like showing specific configurations and effects of the present invention will be described below, but the present invention is not limited to the embodiments.

Examples 1 to 3 A gel coat material having the following composition was applied to the inner surface of a mini bathtub test die, and heated to 90 ° C. by the heat of the die.
(Core mold temperature), cured in about 30 seconds, thickness 0.5
mm of a gel coat layer was formed. [Composition] Unsaturated polyester resin 100 parts by weight (Polymer 9305Z manufactured by Takeda Pharmaceutical Co., Ltd.) Styrene monomer 20 parts by weight Curing agent (benzoyl peroxide) 1.5 parts by weight

A BMC material having the composition shown in Table 1 was placed in the above mold, and heated and pressed at 80 to 90 ° C. (cavity mold temperature 80 ° C., core mold temperature 90 ° C.), 10 MPa, and 700 seconds. Thus, a molded product was obtained. A sample was cut out from the bottom surface of the molded product to form a sample for each test, and the surface smoothness, gloss, bending strength, and Izod impact value were measured for each sample. Table 1 shows the results.
The numbers in the table indicate parts by weight.

[0032]

[Table 1]

The components in the table are as follows. Unsaturated polyester resin: Takeda Pharmaceutical Co., Ltd., Polymer 9305Z Curing agent: Benzoyl peroxide) Glass powder: Average particle size 30 μm, manufactured by Nippon Fellow Co., Ltd.
M-600S FRP powder A: SMC molded product is pulverized and classified into 10-38 mesh FRP powder B: SMC molded product is pulverized and classified into 38 mesh pass FRP powder C: BMC molded product is finely pulverized Classified so as not to contain fibers of 100 μm or more Glass fiber: 3 mm long, made of central glass, ECS
-03-554A

Each evaluation method is as follows. -The surface smoothness and gloss were evaluated by a visual test. -Flexural strength Measured according to JIS-K7203. -Izod impact value Measured in accordance with JIS-K 7110. However, the test pieces were notched.

Comparative Examples 1 and 2 Using the BMC materials having the compositions shown in Table 2, samples in which no gel coat layer was formed were molded in the same manner as in the examples, and evaluation was performed in the same manner as in the examples. Table 2 shows the results.

Reference Example 1 Using a BMC material having the composition shown in Table 2, a sample containing no recycled powder was molded in the same manner as in the example, and was evaluated in the same manner as in the example. Table 2 shows the results.

REFERENCE EXAMPLE 2 A sample was molded in the same manner as in the example, except that a BMC material having a composition shown in Table 2 was used and a recycled powder containing no fiber of 100 μm or more was used. Was evaluated. Table 2 shows the results.

[0038]

[Table 2]

As shown in the results of Tables 1 and 2, in the examples, the surface smoothness and the gloss were significantly improved as compared with the comparative example, and the bending strength was reduced as compared with the reference example 2. It is small, and the Izod impact value is larger than that of Reference Example 2.

Claims (2)

[Claims] After forming a gel coat layer on at least a part of an inner surface of a molding die, a bulk molding compound (BMC) material containing recycled FRP powder is placed in the die, and heating and heating are performed. A method for producing an FRP molded product in which molding is performed under pressure. 2. The FR according to claim 1, wherein the recycled FRP powder is recycled from an FRP molded product formed by sheet molding compound (SMC), spray-up, or hand lay-up.
Manufacturing method of P molded product.