JPS6038260B2 - Method for manufacturing patterned plastic molded products - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the production of plastic material moldings, such as patterned bathtubs.

Conventionally, methods for applying patterns on FRP (reinforced plastic) bathtubs include spray-up and hand-wrap methods, in which patterned cloth woven from glass fibers is layered on the surface of a mold and resin is sprayed from the surface side. This method requires a large number of manufacturing steps, tends to produce an uneven surface layer, and the quality of the product is largely dependent on the skill of the worker.

However, as another method for manufacturing FRP bathtubs, for example, a lower male mold and an upper female mold are used to fill the gap between the two.
The so-called SMC material (Seat M
This method is typified by the so-called SMC method, in which the FRP is melted while heating the pair of molds, diffused to a uniform thickness between the two molds, cured, and then removed from the molds using an olding component plate d). There is a press molding method.

Applying this method, the applicant first developed a method for molding by interposing a patterned cloth on the surface of the mold, and published
I applied as No. 1. However, the density of the warp and warp threads of patterned fabrics tends to be uneven, and especially during molding, the resin heated and melted in the mold is pressurized by the press and flows at high speed, which moves the fabric threads and causes unevenness. A problem arose in that special considerations were required during molding.

The present invention solves the above problems and provides a molding method using a patterned film having one or more pinholes instead of patterned cloth.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

As shown in FIGS. 1 and 2, a resin-impregnated polyester film pattern 3 having a large number of pinholes 3a sewn into a bag shape to match the shape of the bathtub is heated to 80°C below its melting temperature.
A necessary and sufficient amount of FRP SMC material is placed on top of the male mold 1 which is constantly heated to 150°C, and is placed over the mold 1 as much as possible to form a bathtub. After this, the female mold 2 is placed on top, and the male and female molds are closed and pressurized. Through this operation, the FRP material is melted, and as shown in the second figure, the resin of the FRP material is transferred to the surface of the film through the pinholes 3a of the base layer 4 and pattern body 3, forming a transparent resin surface layer 5. At that point, the resin begins to harden. After a predetermined time has elapsed, the mold is opened and the molded product is taken out. As shown in FIG. 3, as the impregnated pattern body 3 before being sewn into the bag shape, the pattern body 3A printed with a desired pattern is made of polyethylene to which a fluid unsaturated polyester resin 8 is attached. A sandwich-like material sandwiched between films 6a and 6b from both sides is used.

That is, polyester resin 8 containing Mg○ is dripped from resin tanks 7a and 7b onto polyethylene films 6a and 6b located on both sides of pattern body 3A, and the resin is bulked with respective doctor knives 9a and 9b so as to maintain a substantially constant amount. The pattern body 3A, which is sandwiched between films with the resin layer inside, passes through an impregnation roll 10 to become an impregnated pattern body 3 formed into a single sheet. . Thereafter, the resin layer is heated and cured in a curing furnace until it gels, and the resin thickens due to the action of M-gen. Then polyethylene films 6a, 6
Sewn with the impregnated pattern left after removing b and place it on a mold. In this way, a thick clear resin layer is formed in advance on the front and back surfaces (only one side may be used) of the pattern body of the present invention to close the pinhole 3a, but this film is heated with the FRP material between the molds. When pressurized, the resin blocking the pinhole melts, allowing the pressurized and flowing molten resin in the FRP material to permeate through the film surface. Therefore, the transparent resin surface layer 5 becomes a thick clear layer consisting of the resin layer impregnated into the cloth and the resin layer in the FRP material. At the same time, since the resin is continuous with the front and back sides of the film through the pinholes 3a, the pattern body 3 and the base layer 4
Adhesion with resin is significantly improved. The number of pinholes 3a in the film 3 is so large that it appears like a cloth grain,
When the transfer of the resin through the pinholes is sufficient, the mold 1 may be covered with a film 3 that is not impregnated with resin, and the resin for forming the base layer 4 may be interposed thereon for molding.

In this case, the resin migrates to the film surface through the pinhole 3a to form the surface layer 5. Another method for forming the transparent surface layer 5 is to form an unsaturated polyester resin transparent surface gel coat layer 5 on the surface of the male mold 1 with a brush, spray gun, etc., and after the layer dries, it will not adhere to the resin. Cover with film.

Furthermore, in order to thicken the surface layer 5, both of the above methods may be roughly combined. That is, a resin-applied patterned body is used, and a gelcoal layer is formed in advance on a mold. Note that as the sandwich-shaped films 6a and 6b, they may be used as they are without being peeled off, as long as they melt at the mold temperature, and thermosetting resin films are most convenient.

In addition to the materials mentioned above, nylon and vinylon are used as materials for the pattern body 3, and film and sheet-like patterns are used, which have strength that does not deform or tear during press molding, heat resistance that does not melt, and printability, and extremely patterns are printed on this. Then, cure thoroughly with steam, etc.

In addition, as plastic materials, unsaturated polyester resin,
Short or cut glass fibers are impregnated in a solution sufficiently mixed with fillers, application materials, mold release materials, etc., and the mixture is thickened with magnesium oxide and made slightly softer.
Other plastics may also be used.

In addition to the above embodiments, surface patterning can also be applied to the outer surface of the bathtub by attaching a patterned cloth to the inner surface of the female mold.

In this case, the male and female molds are arranged upside down. The method of the present invention is not limited to bathtubs, but also boats, tanks, and other small container-shaped molded products made of plastic or FRP materials, and flat or curved molded products such as bathtub aprons and vanity washstands. etc. also applies. As described above, in the present invention, by interposing a pattern film on the surface of a mold and integrally molding a plastic material, it has become possible to impart an arbitrary pattern to a press-molded product with high efficiency.

In addition, since a film is used as the pattern, there is no uneven density phenomenon as with cloth threads, and the pattern of the molded product does not undergo any undesirable deformation.Furthermore, the film has many pinholes, so The sexiness of the resin has improved considerably.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view showing the manufacturing method of the present invention, Fig. 2 is a vertical end view of the main part of the bathtub, Fig. 3 is a diagram of the impregnation treatment process of the pattern body,
1...Male mold, 2...Female mold, 3...
...Pattern film, 4...FRP material base layer, 5...Resin surface layer, 6a, 6b...Polyethylene film, 7a
, 7b... Resin tank, 8... Unsaturated polyester resin, 9a, 9b... Doctor knife, 1
0...Sha-immersion Ronore. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1 A method of hardening and molding by interposing a plastic material between a pair of heated molds, closing the molds and melting the material under pressure, which has a large number of pinholes, and
A method for manufacturing a patterned plastic molded product, characterized in that a film pattern with a pattern is placed along the surface of the one mold, and the plastic material is interposed between the pattern and the other mold. .