JPS5944962B2 - Method for manufacturing molded product with marble pattern - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing molded articles having a marble pattern by SMC molding.

In recent years, artificial marble made from synthetic resin has been used for bathtubs, washstands, kitchen countertops, etc., but most of them are made by hand and have poor productivity.

Recently, the hot-press molding method using SMC (sheet molding compound), which is mechanized and mass-producible, has become popular for glass fiber reinforced plastic (FRP) products. The object of the present invention is to provide a method for manufacturing molded articles having SMC is Sheet Molding Compound
Glass is made from a resin mixture that is usually based on unsaturated polyester resin that has been chemically thickened with MgO, etc., and contains fillers, colorants, low-shrinkage agents, curing agents, mold release agents, etc. A sheet-shaped molding material made by impregnating cut mat or rope fibers. Both sides are covered with a thermoplastic film, which is peeled off before use. This product is suitable for molding parts with ribs and boss structures, and the molding conditions are generally 1400C and 50-150kg.
/cwL13 to 5 minutes. Recently, a method of forming a marble pattern using SMC molding has been proposed, and these can be broadly divided into 1) methods that expect the transparency and depth of texture that marble has, and 2) methods that expect the color pattern of marble. .

Regarding the former, SMC contains unsaturated polyester resin, glass fiber, and the above-mentioned various additives as its constituent elements, and even if fillers and colorants are excluded, there is a natural limit to its transparency. Regarding the latter, most of them are force methods that create a flow pattern in the molding process by combining SMC made by thickening resins of different colors, but SMC molding requires a long flow distance and short curing conditions. As a result, dissimilar colored compounds mix together, resulting in color smearing, and it is generally difficult to control flow and color contrast. From this experience,
Furthermore, we focused on the coloring of fibers, and when we dispersed colored fibers into the glass fiber base material during the process of making SMC, the surface after molding had a colored pattern, but it did not have large striped patterns like marble. There were no eyes, and each colored fiber looked like hair, making it unsightly.

It is not suitable for situations where observation is to be done at close range, such as in a bathtub. As a result of various studies, we made an SMC using only colored fibers in advance, and placed uncolored fibers on the mold during molding.
When MC and colored fiber SMC were arranged appropriately according to the pattern, the surface after molding had large striped pattern cracks here and there, and the colored fibers did not have an unsightly hair-like appearance and were beautiful. It was possible to form a marble pattern.
In addition, the SMC made of colored fibers is made into a flake shape with a thickness of 1 to 211 mm and a size of 10 to 20 mm square, and this is
When it was sprayed together with glass fiber during the process of making MC, the surface exhibited a beautiful marble pattern after molding. This is because only the colored fibers are wrapped in resin and semi-solidified in advance, so even when flowing under pressure, the six colored fibers and the resin flow together as one, creating a moderate flow and moving with less dispersion and mixing with other things. Therefore, it is recognized that not only a large split pattern is formed, but also the colored fibers are not dispersed one by one.

Furthermore, when 30 to 120 parts by weight of hydrated alumina was added to 100 parts of resin instead of the conventional filler for SMC, CaCO, the surface after molding was translucent and milky white, and the deep fibers of B3 were slightly visible. It looks like it stands out, and we were able to recreate the deep and elegant feel of marble.

This is believed to be because hydrated alumina has superior transparency when impregnated with resin compared to CacO3. In short, in the present invention, the colored pattern component is made into a fibrous material, and by wrapping this in advance with resin and semi-solidifying it, it becomes easier to control the flow during molding. This is because the color contrast has improved and it has become possible to suppress excessive mixing and dispersion of colored components.

SMC using colored fibers may be made in several colors depending on the pattern, and it is also optional to make SMC from fibers of mixed colors from the beginning.

The fibers used for coloring are inorganic fibers or chemical fibers. Inorganic fibers include glass fibers and carbon fibers, and chemical fibers include recycled fibers such as rayon, semi-synthetic fibers such as acetate, and synthetic fibers such as polyester and polyacrylonitrile. The amount, thickness, and length of colored fibers can vary depending on the pattern and are not limited. -゛The filler used in SMC is usually CacO3, but hydrated alumina is better for achieving marble-like translucency.

Even if CacO3 is used in a small amount, there will be no problem depending on the pattern. When the purpose is to create a marble pattern using colored fibers as in the present invention, it is an essential condition that the colored fiber pattern should appear slightly raised at a certain depth, and for this purpose it must not be opaque; Further, it is desirable that the material is not transparent but milky-white and translucent; that is, it is necessary to have both depth and color pattern. For this purpose, it is preferable to use hydrated alumina (B5, in particular its amount and particle size, which affects the BS transparency, in a proportion of 30 to 120 parts by weight, preferably 40 to 60 parts by weight, based on 100 parts of resin/) 5 Usually, the particle size is 10~
20, mbS is appropriate. Example 1 Unsaturated polyester resin 100BI). Hydrated alumina (
A black glass rope cut into 25 mm is impregnated with a compound made by adding a thickener (MgO), a low shrinkage agent, a mold release agent hardener, etc. to 50 parts of Higilite (H-31, manufactured by Showa Denko). (G, .C, 2O%) and then thickened and cured to produce SMC.

This has a thickness of 2m TL and a size of 20W! When manufacturing SMC using uncolored glass fiber cut into m-square thin pieces using the same force method as above, when scattering the glass roping cut pieces, the black SMC thin pieces are simultaneously spaced apart. and add scattered operations. SM made in this way
Place several sheets of C on the mold and heat at 140℃, 100kg/CTi
When molded under hot pressure conditions of L and 5 minutes, a molded product b≦with a deep marble pattern on the surface was obtained. The marble pattern forming force method according to the present invention can be realized by adding relatively simple operations to the conventional SMC forming method, and therefore is useful as a force method for mass production of marble pattern molded products.

Claims (1)

[Claims] 1 When producing SMC with an uncolored fiber base material using 30 to 120 parts by weight of hydrated alumina as a filler for 100 parts by weight of an unsaturated polyester resin, the SMC with a colored fiber base material is made into flakes. A method for producing a molded article having a marble pattern, characterized in that SMC is produced by appropriately scattering the uncolored fibers together with the uncolored fibers, and the SMC is then hot-press molded.