JPH0741681B2 - Method for manufacturing reinforced plastic molded products - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a reinforced plastic molded product which is molded by a hand-up method, a spray-up method or the like.

(Prior Art) FIG. 5 shows the structure of an FRP molded product (for example, a bathtub or a washing room) molded by the hand-up method or the spray-up method.

That is, in the conventional FRP molded product, the intermediate laminate layer b was formed on the upper surface of the gel coat layer a, and the backing laminate layer c was formed on the upper surface of the intermediate laminate layer b. In addition, the code | symbol d in the figure is a shaping | molding die.

In the method of manufacturing an FRP molded product having such a structure, first, a gel coat resin as a surface component of the product is laminated on the upper surface of the molding die d to a thickness of about 0.2 to 0.6 m / m and then cured to form a gel coat layer a. Then, a thermosetting resin such as a polyester resin mixed with glass fibers is laminated on the upper surface of the gel coat layer a to a thickness of about 0.5 to 1.0 m / m, and cured to remove bubbles. Then, an intermediate laminated layer b is formed, and a thermosetting resin such as polyester resin mixed with glass fiber is laminated on the upper surface of the intermediate laminated layer b to a thickness of about 0.5 to 2.0 m / m. After curing, defoaming was performed to form the backing laminate layer c. That is, the conventional manufacturing method is: gel coat layer formation → curing (about 10 minutes) → intermediate laminate layer formation → defoaming (about 5 minutes)
Min) → curing (about 10 minutes) → backing laminate layer formation → defoaming (about 5 minutes) → curing (about 10 minutes), and it takes about 40 minutes for curing and defoaming in all the steps. Was.

(Problems to be Solved by the Invention) As described above, when the FRP molded product having the above-described conventional structure is manufactured by the above-described conventional manufacturing method, it is necessary to mold two types of laminate layers, and thus the hand-up method is used. Alternatively, there has been a problem that a lot of man-hours are required for the laminating process by the spray-up method and the equipment for laminating and curing becomes large in scale. In addition, since defoaming is performed manually by forming the upper surface of the laminate layer with a roll, air bubbles may remain, and as a result, pinholes and voids may be generated on the surface of the gel coat layer a, and heat resistance and water resistance may be increased. There was a problem that the surface blistered due to poor property.

The gel coat layer a, which is the surface of the molded product, is usually made of a special resin (for example, a colored gel coat) because of its appearance, but such a special resin is expensive in cost. Therefore, in order to reduce the manufacturing cost,
It is necessary to form the gel coat layer a, which is the surface layer, as thinly as possible. However, if the gel coat layer a is formed as thin as described above, the above-mentioned problems (that is, problems such as pinholes, voids, and surface swelling on the surface of the gel coat layer a) occur. Will occur more significantly. Therefore, it has been conventionally desired to develop a manufacturing method capable of solving the above-mentioned problems while keeping the gel coat layer a serving as the surface thin.

The present invention was devised to solve the above problems, and an object thereof is to provide a method for producing a reinforced plastic molded product which is good in appearance while keeping the gel coat layer as a surface thin. is there.

(Means for Solving Problems) In order to solve the above problems, the method for producing a reinforced plastic molded product according to the present invention is a method for producing a reinforced plastic molded product by a hand-up method or a spray up method. Then, the gel coat resin is laminated on the molding die and then cured to form a gel coat layer.The gel coat reinforcing layer is formed by laminating a resin that is cured by ultraviolet rays on the gel coat layer and then irradiating the ultraviolet rays to cure the resin. The laminate resin is formed, and a laminating resin is laminated on the gel coat reinforcing layer, followed by defoaming and curing to form a laminate layer.

(Function) The method for producing a reinforced plastic molded article of the present invention relates to the production of a gel coat layer, a gel coat reinforcing layer, and a laminate layer, which comprises laminating a gel coat resin on a molding die and then curing the gel coat resin for gel coating. After forming a layer, laminating a resin that is cured by ultraviolet rays on the gel coat layer, and then irradiating with ultraviolet rays to form a gel coat reinforcing layer, and then laminating a resin for laminating on the gel coat reinforcing layer. The laminated layer is formed by defoaming and curing. That is, gel coat layer formation → curing (about 10 minutes) → gel coat reinforcing layer formation → ultraviolet curing (depending on the type of resin, about 1 minute for unsaturated polyester resin) → laminating layer formation → defoaming (about 5 minutes) Minutes)
→ Curing (about 10 minutes), and the time required for curing and defoaming in all the steps is about 26 minutes. In addition, since the gel coat reinforcing layer is UV-cured, the viscosity does not decrease even if the layer thickness increases, and therefore dripping does not occur on the molding die.

That is, according to the manufacturing method of the present invention, the gel coat layer is
Due to the layered structure, even if the gel coat layer serving as the surface of the molded product is formed thin, by forming the next gel coat reinforcing layer thick, the gel coat layer as a whole can be kept at a constant thickness. This means that when an expensive colored gel coat is used for the gel coat layer which is the surface of the molded product, the colored gel coat layer can be made thinner and the material cost can be reduced accordingly. Further, even if bubbles are left by defoaming after forming the laminate layer on the gel coat reinforcing layer, if the gel coat reinforcing layer is formed thickly, the influence of the remaining bubbles extends to the gel coat layer which becomes the surface layer. In that sense, the defoaming process becomes simple.

Further, even if the gel coat reinforcing layer is formed thick, it can be performed in a short time because it is cured by ultraviolet light, and it does not attack the first (the surface) gel coat layer formed by heat curing.
If the gel coat reinforcing layer is formed by heat curing instead of UV curing according to the present invention, the styrene monomer penetrates into the first gel coat layer (becomes the surface) at the time of heat curing of the gel coat reinforcing layer to improve the appearance of the surface. Cause damage,
Such a situation does not occur in the ultraviolet curing of the present invention.

That is, the manufacturing method of the present invention is characterized in that the advantages of heat curing (formation of gel coat layer to be a surface layer) and the advantages of ultraviolet curing (formation of gel coat reinforcing layer) are effectively combined. Is to have.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a partial vertical sectional view of a reinforced plastic molded product molded by the manufacturing method of the present invention. In addition,
The figure shows the state before the mold is released from the mold 5.

In the figure, a reinforced plastic molded article (for example, a bath) of the present invention has a gel coat layer 1 which is a surface portion of the molded article.
It comprises a gel coat reinforcing layer 2 formed on the upper surface of the gel coat layer 1 and a laminating layer 3 formed on the upper surface of the gel coat reinforcing layer 2.

An unsaturated polyester resin is the most common resin for forming the gel coat layer 1 and the laminate layer 3. However, when the molded product is a water bath product such as a bath or a washing place, for example, a bisphenol resin or an isophthalic acid resin having excellent water resistance and heat resistance is used as the gel coat layer 1.

The gel coat reinforcing layer 2 is one that is cured by ultraviolet rays. That is, as the constituent material, a mixture of an unsaturated polyester resin or a prepolymer and a monomer, and a photoinitiator are essential constituent materials, and if necessary, a mixture with an additive is used. The prepolymers are mainly polyester acrylates, epoxy acrylates, polyurethane acrylates, and other polyether acrylates, melamine acrylates, alkyd acrylates, silicone acrylates, and the like. Monomers include monofunctional acrylates and polyfunctional acrylates. Monofunctional acrylates include lauryl acrylate, 2-ethylhexyl acrylate, and 2-hydroxyethyl acrylate, and polyfunctional acrylates include dicyclohexyl acrylate. Examples include pentenyl acrylate, dicyclopentenyloxyethyl acrylate, and trimethylolpropane tri acrylate. Examples of the photoinitiator include acetophenone, Michler's ketone, benzyl, benzoin, benzyl dimethyl ketal, and tetramethyl thiuram monosulfide. The photoinitiator is mixed with 0.1 to 5% by weight (generally 2% by weight or less) with respect to the unsaturated polyester resin and the mixture. As an additive,
A sensitizer, a storage stabilizer, a thixotropic agent and the like are used. The sensitizer is used with the photoinitiator to accelerate the reaction, and examples thereof include triethylamine, diethylaminoethyl methacrylate, and triethylenetetramine used with benzyl. Examples of storage stabilizers include quaternary ammonium chloride, organic acids (lactic acid, oxalic acid, citric acid, etc.), hydroquinone and its methyl ether, tertiary butyl pyrocatechol and the like. In addition, in order to improve strength, water resistance, and heat resistance, in addition to the above-described constituent materials, a short glass fiber having a length of 1 mm or less is 15% by weight or less (preferably 5 to 10% by weight) and a filler such as calcium carbonate. A mixture of 30% by weight or less (preferably 5 to 20% by weight) is used. By adding this glass fiber, a molded product having excellent physical properties and surface finish can be obtained.

Next, a method of manufacturing the reinforced plastic molded product having the above structure will be described with reference to FIGS. 3 and 4. However, FIG. 3 shows an ultraviolet irradiation device 10, and ultraviolet lamps 11, 11, ... Are provided on the entire inner wall. As the ultraviolet lamp, mercury lamp of discharge lamp type, metal halide lamp,
A light source such as a fluorescent lamp is used, but a low-pressure mercury lamp or a high-pressure mercury lamp is practically used. Also, the fourth
The figure shows an example of molding equipment by spray-up method.
Is a mold, 12 is a turntable, 13 is a spray nozzle,
Reference numeral 14 is a roving cutter, 15 is a resin supply hose, 16 is a glass roving, and 17 is a storage chamber that stores these devices and members.

First, the gel coat resin described above is laminated on the molding die 5 formed in a predetermined shape to a predetermined thickness by a spray-up method or a hand-up method, and then cured at room temperature or by heating to form the gel coat layer 1. Form. next,
On the gel coat layer 1, the above-mentioned resin for gel coat reinforcement was laminated to a predetermined thickness by a spray-up method or a hand-up method, and then stored in an irradiation device 10 (see FIG. 3) together with a mold 5. The gel coat reinforcing layer 2 is formed by curing (or passing it through). In this case, even if the gel coat reinforcing layer 2 is thickly formed, it can be performed in a short time because it is cured by ultraviolet light, and the first gel coat layer 1 formed by heat curing is not damaged. That is, when the gel coat reinforcing layer 2 is formed by thermosetting, the styrene monomer may enter the gel coat layer 1 during thermosetting of the gel coat reinforcing layer 2 and cause the appearance of the gel coat layer 1 to be impaired. The reason for this is that the occurrence of such a situation can be prevented by performing ultraviolet curing as described above.

Next, on the gel coat reinforcing layer 2 thus formed, glass fibers and a thermosetting resin such as a polyester resin are mixed by a hand-up method or a spray-up method and laminated to a predetermined thickness to remove bubbles. After that, the laminate layer 3 is formed by heating or curing at room temperature.
In this case, even if air bubbles remain due to defoaming performed after forming the laminate layer 3 on the gel coat reinforcing layer 2, if the gel coat reinforcing layer 2 is formed thickly, the effect of the remaining air bubbles becomes the surface layer. It does not extend to layer 1.
Therefore, the defoaming step can be performed without being concerned about the influence on the gel coat layer 1.

In this way, a molded product having the layer structure shown in FIG. 1 is obtained.

In forming the laminating layer 3, the inside of the storage chamber 17 shown in FIG. 4 is evacuated, and then the laminating layer 3 and the top coat layer 4 are sequentially laminated by the vacuum spray-up method, and then the atmospheric pressure is applied. It may be exposed to (atmospheric pressure) and heated or cured at room temperature. This way,
It is possible to omit the defoaming work that was performed manually.
As the top coat layer 4, only resin is laminated and glass fiber is not used. Therefore, the top coat layer 4
The resin forming the resin is preferably a resin having thixotropy by itself. The layered structure of the molded product thus molded is shown in FIG.

(Effects of the Invention) As described above, according to the method for manufacturing a reinforced plastic molded product of the present invention, since the lamination molding is performed only once, the man-hours for the lamination molding are significantly reduced as compared with the conventional manufacturing method. In addition to being able to do so, labor saving of equipment can be achieved. In addition, the time required for defoaming and curing in all steps can be significantly shortened compared to the conventional manufacturing method, and the number of defoaming operations during the steps can be reduced, so that the quality due to the remaining bubbles Can be prevented. Furthermore, even if air bubbles remain due to defoaming performed after forming the laminate layer, the presence of the gel coat reinforcing layer prevents the remaining air bubbles from affecting the gel coat layer serving as the surface layer. Therefore, it is possible to perform defoaming without worrying about the influence on the gel coat layer, which simplifies the defoaming step.
Furthermore, when the gel coat reinforcing layer is formed by thermosetting, styrene monomer penetrates into the gel coat layer during thermosetting of the gel coat reinforcing layer, which causes the appearance of the gel coat layer to be impaired. Curing also prevents the occurrence of such a situation. Furthermore, by forming the gel coat layer into a two-layer structure, even if the gel coat layer serving as the surface of the molded product is formed thin, by forming the next gel coat reinforcing layer thick, the gel coat layer as a whole has a constant thickness. Can be kept. This means that when an expensive colored gel coat is used for the gel coat layer which is the surface of the molded product, the colored gel coat layer can be thinned and the material cost can be reduced accordingly.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a reinforced plastic molded product obtained by the method of the present invention, FIG. 2 is a vertical sectional view of a reinforced plastic molded product in which a laminate layer and a top coat layer are formed in a vacuum state, and FIG. 3 is a spray. FIG. 4 is a schematic configuration diagram showing an example of a molding device by the up method, FIG. 4 is a schematic configuration diagram of an ultraviolet irradiation device, and FIG. 5 is a vertical sectional view of a conventional reinforced plastic molded product. 1 ... Gel coat layer, 2 ... Gel coat reinforcing layer 3 ... Laminate layer

 ─────────────────────────────────────────────────── --- Continuation of front page (56) References JP-A-60-149417 (JP, A) JP-A-50-107070 (JP, A) JP-A-53-102392 (JP, A) JP-A-50- 34363 (JP, A)

Claims (1)

[Claims] 1. A gel coat is formed by laminating a gel coat resin on a molding die and then curing the gel coat layer to form a gel coat layer, and laminating a resin which is cured by ultraviolet rays on the gel coat layer and then irradiating and curing the resin. A method for producing a reinforced plastic molded article, comprising forming a reinforcing layer, laminating a laminating resin on the gel coat reinforcing layer, defoaming and curing the resin to form a laminating layer.