Most of the paint materials currently used for motorcycles contain a large amount of Volatile Organic Compounds. Volatile Organic Compounds are environmental load substances, and there is a strong demand for reducing their emissions in recent years. Many of a motorcycle’s exterior parts are made of ABS plastics or PA plastics. These two plastic materials have different film adhesion mechanisms and adhesion strengths. Therefore it was necessary to use different conductive primers and it was one of the factors that caused a loss of time and materials in the painting processes. We challenged those two objectives, i.e., the reduction of Volatile Organic Compounds and the common use of the same conductive primer for different parts materials, by combining two kinds of resins originally designed individually, i.e., urethane resins with carboxylic acid groups and acrylic resins with amide groups, which have different properties. Many of the plastic parts used in motorcycles are painted manually because they have difficult areas to be painted by automated painting machines. Thus, the viscosity was adjusted to satisfy both the controllability of paint sagging and the surface smoothness to maintain the efficiency of paint workers’ operations by using a thixotropic rheology control agent.
Article of Honda R&D Technical Review Vol.25 No.2 (154 - 164)