Teijin Develops Polycarbonate Resin for In-mold Decorations

Teijin Limited announced today its development of a polycarbonate (PC) resin suitable for in-mold decoration, an efficient method of decorating plastic parts during the injection molding process. The new PC resin will allow manufacturers to enhance productivity while reducing product weight. Potential applications include casings of mobile devices such as smartphones, tablets and notebooks, as well as medical devices and automotive parts.

Incorporating special glass fibers and additive agents, the new PC resin achieves excellent rigidity and dimensional stability for thin-wall molded casings, as well as optimized surface flatness for in-mold decoration and 40% higher fluidity than conventional glass fiber-reinforced PC resins. In addition, Teijin’s proprietary flame-retardant technology enables the new PC resin to achieve top-level flame retardancy – equivalent to UL94V-0 at 0.6mm.

Reducing the weight of mobile device casings demands a combination of thin-wall molding and high rigidity. Materials that meet these requirements include carbon fiber-reinforced plastics and magnesium alloys, but they require additional steps for pattern printing, coating or other post-processing after the casing has been molded. The added production costs have limited use to some high-end models.

Conventional PC or nylon resin composites are commonly used for the casings of mass-market models, but these materials are prone to wrinkles, cracks or other degradation in surfaces during in-mold decoration. Also, it has been a challenge to achieve desired levels of dimensional stability, coating and flame-retardancy in thin-wall molding made of these materials.

Source: Teijin