JPH0367606B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method for manufacturing a molded product having a stone grain pattern formed on its surface, such as a waterproof floor pan for a bathroom.

[Background Art] Conventionally, press molding methods and hand lay-up methods have been used to produce reinforced molded products having a stone grain pattern. Press molding methods include SMC (Sheet Molding Compound) and BMC.
This is a method in which grain-forming materials such as granular stones and resin are mixed into a molding material called (Bulk Molding Compound), and molding is performed using direct pressure or injection molding methods. In addition, in the hand lay-up method, a clear resin is applied to the surface of the mold and gelled, and then a mixture of grain-forming particles and resin molding material is sprayed with a spray gun, etc. In this method, the back layer is molded and hardened using glass fiber and resin.

However, the press molding method has good productivity because it can be manufactured in one molding process, and although it is advantageous in terms of manufacturing costs (compared to the hand lay-up method, the productivity is 10 times higher and the manufacturing cost is 1/2). , the stone pattern is
The design is made of grain-forming particles mixed with SMC or BMC, so it is formed on the entire surface of the molded product, and it is difficult to form a grain pattern only on a part of the surface. There is also a problem in that the strength of the molded product is easily affected because grain-forming particles are mixed throughout the molded product. In addition, in the hand lay-up method, the stone pattern can be formed by spraying a mixture of stone grain-forming grains and resin molding material with a spray gun, etc. It is possible to form a stone pattern, giving freedom in terms of design, and since the grain-forming particles exist only on the surface layer of the molded product, the strength of the molded product is affected by the grain-forming grains. Although it is advantageous in that it does not suffer from damage, it requires a large number of molding steps, has poor productivity, and has problems in terms of manufacturing costs.

[Object of the Invention] The present invention has been made in view of the above-mentioned points, and it is possible to form a stone pattern only on a part of the surface, without fear of deterioration in strength, and moreover, it is easy to form. It is an object of the present invention to provide a method for manufacturing a molded article with a stone grain pattern, which can be manufactured with fewer man-hours and with good productivity.

[Disclosure of the Invention] The method for manufacturing a molded product with a stone pattern according to the present invention includes forming a stone sheet 3 by attaching grain-forming grains 2 to the surface of a release sheet 1, and also forming a stone sheet 3. 3 on the surface of the mold 4 so that the granules 2 are exposed, then a glass cloth 10 is placed on the stone sheet 3, and the molding material 5 is placed on the glass cloth 10 and hardened. This method is characterized by peeling off the mold release sheet 1 from the cured molded product, and at the same time when molding the molding material 5, grain-forming grains 2 are attached only to the surface of the molded product. The present invention will be described in detail below.

The stone sheet 3 is made by applying an adhesive 9 to the surface of the release sheet 1, and then uniformly scattering granular materials 2 such as granular stones or granular resin having a stone-like appearance on the surface of the release sheet 1. 2 to the release sheet 1, it is formed as shown in FIG. 1a. As the release sheet 1, a release paper or a release resin sheet such as a polyester sheet or a nylon sheet can be used, and any material may be used as long as the resin of the molding material does not penetrate during molding and is difficult to tear when peeled off. . When manufacturing a molded product by the pressing method using this stone sheet 3, the stone sheet 3 is first placed on the surface of a mold 4 formed by a metal mold as shown in Fig. 1b. Set. The stone sheet 3 is set on the surface of the mold 4 so that the granules 2 are exposed on the upper surface, and is set in the mold 4 at a portion where a stone pattern is to be formed on the molded product.
Then, a glass cloth 10 is layered on top of the stone sheet 3, a molding material 5 such as SMC or BMC is layered and set on the mold 4 from above the glass cloth 10, and then the upper mold of the mold 4 is replaced with the lower mold. It is molded by tightening it, pressurizing it, and heating it (the figure shows only the lower mold, and the upper mold is omitted). At this time, even if the molding material 5 has good fluidity, the grain-forming granules 2 do not flow due to the presence of the glass cloth 10. After the molding is performed in this manner, the molded product formed by hardening the molding material 5 is removed from the mold 4, and the release sheet 1 is peeled off from the stone sheet 3. The granules 2 in the stone sheet 3 remain fixed to the surface of the molded product, and a stone pattern is formed by the granules 2, making it possible to obtain a molded product with a stone pattern. It is possible. If you want to provide a clear layer on the surface of the stone pattern formed by the granules 2,
After molding, the release sheet 1 may be peeled off and then a clear resin may be applied by spray or brush, but instead of the adhesive 9, a clear resin may be applied to the surface of the release sheet 1 and granular particles may be applied on the surface of the release sheet 1. It is also possible to use a stone sheet 3 prepared by adhering the particulate material 2 to the release sheet 1 by spraying the material 2 and curing the clear resin. In the molded product with a stone pattern formed in this way, by arbitrarily setting the setting position of the stone sheet 3 in the flat part of the mold 4, the part where the stone pattern is desired to be provided can be formed. Only in this method can a stone grain pattern be formed in the molded product, and the granules 2 are present only in the surface layer of the molded product, so that the granules 2 do not impair the strength of the molded product. Also, the number of man-hours for molding is 4 molds.
It is only necessary to set the stone sheet 3 and the molding material 5 once, and manufacturing can be carried out with high productivity.

Although the manufacturing method using the press molding method, which has excellent productivity, has been described above, the present invention can also be applied to the hand lay-up method. That is, after placing and setting the stone sheet 3 on the mold 4, gel coat resin 11 is applied to the surface of the stone sheet 3 and the surface of the mold 4 other than where the stone sheet 3 is placed, as shown in FIG. After the gel coat resin 11 is applied and cured, a molding material 5 such as unsaturated polyester resin and glass mat is hand-layed up and molded, and the gel coat resin 11 is cured while being reinforced with reinforcing wood or the like. After the molding is performed in this manner, the molded product formed by hardening the molding material 5 is removed from the mold 4, and the release sheet 1 is peeled off from the stone sheet 3. stone sheet 3
The granules 2 remain fixedly attached to the surface of the molded product, and the grain pattern is formed by the grains 2, making it possible to obtain a molded product with a grain pattern.

Next, the present invention will be further explained using specific examples.

Creating a stone sheet (1) Use a 50μ thick polyester sheet or nylon sheet as a release sheet, apply a synthetic rubber adhesive to the surface of the release sheet, and then add granite with a diameter of 1 to 3 mm on top. A stone sheet was created in which the granite grains were evenly dispersed and adhered to a release sheet using an adhesive.

Preparation of stone sheet (2) A polyester sheet or nylon sheet with a thickness of 50μ was used as a release sheet, and a clear resin was applied to the surface of the release sheet. As a clear resin, 100 parts by weight of an unsaturated polyester resin is mixed with a 0.6% aqueous solution of cobalt naphthenate as a curing accelerator.
0.5 parts by weight and 1 part by weight of methyl ethyl ketone peroxide as a hardening agent were mixed and stirred, and the coating thickness was set to 0.1 to 0.2 mm. After applying the clear resin in this way, granite grains with a diameter of 1 to 3 mm are further uniformly sprinkled on top of the clear resin, the clear resin is cured, and a stone sheet with the granite grains attached to the release sheet is formed using the clear resin. Created.

Molding First, as shown in Figure 3a, place a stone sheet on the wash area molding part of the mold for waterproof floor pans for bathroom units, with the release sheet facing toward the surface of the mold, and then place the stone sheet about 10mm further than the stone sheet. A glass cloth with a large width was placed on top of the stone sheet. After this, the third
Place the SMC material on the mold as shown in Figure b,
The temperature of the mold is 145℃ on the product side and 130℃ on the back side.
Pressure and heat molding was carried out under conditions of a pressing force of 1200 tons and a pressing time of 4 minutes. After this, the mold is removed from the mold, followed by post-processing such as deburring, and the release sheet is peeled off from the surface of the molded product to create a waterproof bathroom unit with a stone-grain pattern in the washing area. Got floor bread. still,
When using the stone sheet obtained in (1) above, if there is a performance problem because the granite grains are directly exposed on the surface of the molded product, a clear resin can be applied on top of it to form a clear layer. However, when the stone sheet obtained in (2) above is used, the granite grains are already coated with clear resin, so the clear layer after forming is No formation was necessary.

[Effects of the Invention] As described above, in the present invention, a stone sheet is formed by attaching grain-forming grains to the surface of a release sheet, and this stone sheet is shaped so that the grains are exposed. The molding material was set on the surface of the mold, then overlaid on the stone sheet, set in the mold and cured, and then the mold release sheet was peeled off from the cured molded product, so the stone sheet was placed on the mold. By setting the set position arbitrarily, it is possible to form a stone pattern on the molded product only in the part where the stone pattern is desired, which provides excellent design freedom in forming the stone pattern. Moreover, the granules are present only in the surface layer of the molded product, and there is no risk of affecting the strength of the molded product.Furthermore, a glass cloth is sandwiched between the stone sheet and the molding material. Since it is molded with a glass cloth, even if the molding material has good fluidity, the flow of the grain-forming particles is suppressed by the glass cloth, and a beautiful grain pattern can be formed without the grain pattern flowing. . In addition, the number of man-hours required for molding can be completed only once, after setting the stone sheet and molding material in the mold, making it possible to manufacture with high productivity.

[Brief explanation of drawings]

Figures 1a and b are sectional views of one embodiment of the present invention, Figure 2 are sectional views of another embodiment of the same, and Figures 3a and b.
1 is a sectional view and a plan view showing the manufacture of a waterproof pan for a bathroom unit. 1 is a release sheet, 2 is a granular material for forming grains, 3 is a stone sheet, 4 is a mold, and 5 is a molding material.

Claims (1)

[Claims] 1. Attach grain-forming grains to the surface of a release sheet to form a stone sheet, and set this stone sheet on the surface of a mold so that the grains are exposed. Next, layer glass cloth on the stone sheet. A method for manufacturing a molded article with a stone grain pattern, which comprises placing the molding material on a glass cloth and setting the molding material in a mold and curing it, and then peeling off a release sheet from the cured molded article.