We are a one-stop shop for the development and manufacturing of compound products tailored by application and with plastics as their raw materials. The industries we serve are various and include automobiles, home appliances, and health care. We manufacture products to order, tailored to customers’ needs, using proprietary compound technologies.




Three strengths of Rhombic’s compound products

  1. (1)Technical ability
    We have delivered numerous difficult-to-perfect compound technologies, including "coloration technologies," which add color to resins, and "kneading technology," which combines different materials, and have received high praise from those with whom we do business.  We are confident that our value as a company will only increase as demands for plastic materials, in terms of function and physical properties, become more advanced, as they currently are.
  2. (2)Responsiveness
    We manufacture compound products for a wide range of applications, from automobiles and industrial materials to healthcare device components and food packaging. We thus offer total solutions for the plastic processing industry.  We have all the required knowledge in all departments, whether it is concerning raw materials, molding, or transportation. We provide thorough support for all your on-the-ground needs, wherever plastics are used.
  3. (3)Development ability
    As a professional materials organization, we look to the infinite possibilities for plastics and focus on research and development to apply plastic technologies to an even broader range of applications.  We are creating new value in our technology development wing, which is equipped with the latest facilities. Through close partnerships with those on the ground in manufacturing, located next door, we are actively engaged in improving the quality and lowering the cost of existing products.


(Technology Development Wing) Development Facility



We have five factories, located in Mie Prefecture; Ibaraki Prefecture; Okayama Prefecture; Saitama Prefecture; and Aichi Prefecture.

  • Yokkaichi Factory (Yokkaichi, Mie Prefecture)
    This cutting-edge compound factory pursues efficiency and effort-saving and has a high labor-efficiency rate. It primarily manufactures compound products that are mainly constituted from polyolefin, thermoplastic elastomer and carbon-containing masterbatches. To meet even more customer requests, it is also equipped with a clean building, in which contamination with foreign material is removed from medical components and food packaging. There is also the technology development wing next door, helping us to engage in industrial technology development, even in response to difficult problems, through close cooperation with research and development staff.
  • Kashima Factory (Kamisu, Ibaraki Prefecture)
    The Kashima factory is home to one of the largest kneading extrusion equipment facilities in Japan and manufactures polyolefin resin compound products.
  • Mizushima (Kurashiki, Okayama Prefecture)
    The factory is located within the larger Mizushima operations site, which is the base for Mitsubishi Chemical’s petrochemical business. The factory primarily manufactures compound products for food packaging and industrial materials.
  • Saitama Factory (Kazo, Saitama Prefecture)
    This factory primarily manufacturers materials for automobiles and industry and also produces small-lot coloring products.
  • Nagoya Factory (Nagoya, Aichi Prefecture)
    This is the flagship factory for vinyl chloride compounds and has accumulated considerable technology and experience. On these bases, it manufactures high-quality soft vinyl chloride compound products.

Inquiries Concerning Products

Resin compound product


View the products of RHOMBIC[Open in a new window]