Tanazawa Hakkosha develops technology to reduce gloss of resin molded products

Tanazawa Hakkosha, Japan (Headquarters: Higashi-Osaka City, Osaka Prefecture) has developed 'CeramatteDuring the specific processing, fine granular ceramics with a diameter of about 20 μm are sprayed on the surface of the mold and fixed by firing. It is possible to combine existing wrinkle processing technologies to make weld lines and the like inconspicuous, thus greatly reducing the need for finishing by painting or the like. According to the company, this technology has achieved mass production of 50,000 moldings in automotive interior parts. Tanazawa Hakkosha specializes in wrinkle processing. Wrinkles are fine irregularities (about 200 μm in height) formed on the surface, so they have the effect of reducing the degree of specular reflection. However, even in combination with sandblasting, there is a reduction in gloss. limit. According to the company, the specular gloss can only be reduced to a maximum of 0.5 at this time. In addition, the gloss also varies greatly depending on the resin material. When molding different materials with the same mold, if only the molding conditions are adjusted, most of them cannot achieve uniform gloss. For example, when combining parts made of ABS (acrylonitrile-butadiene-styrene) resin, which is prone to gloss, and parts made of PP (polypropylene) resin, which is less glossy, it is necessary to adjust the molding conditions no matter what. , it is difficult to completely eliminate the gloss difference between the two. The newly developed Ceramatte technology reduces gloss due to the effect of a ceramic film on the mold surface. It can also reduce the gloss difference caused by the difference between ABS and PP and other materials. Although the detailed mechanism is unknown, Tanazawa Hakkosha speculates: 'This may be because the surface of each ceramic particle has very fine irregularities, and the thermal conductivity of the ceramic film is also low, and the resin flows into it before solidification. The reason for these fine irregularities.” Regarding the cost of Ceramatte, Tanazawa Hakkosha said that “it is about the same level as normal wrinkling.” Although the cost will be approximately doubled when the wrinkle and ceramatte processing technologies are used at the same time, 'the part of the increase in cost is expected to be fully compensated by reducing treatments such as trimming' (Tandazawa Hakkosha). The company said that in the future, it will provide additional Ceramatte processing services to molds in use that have already been wrinkled by other companies.