Colored Engineering Resins for High Strain/Thin Walled Applications

Abstract

As part designers push the limits of strain requirements on levers and snap-fits, or continue to reduce size and cost by designing thinner and thinner sections, processors often are faced with breakage problems with colored resins. This chapter discusses two main causes of breakage problems with engineering resins—colorant selection and colorant dispersion. Much has been documented with respect to the effect of colorants, primarily carbon black and titanium dioxide, on the properties of polymers. Properties talked about are usually viscosity of color concentrates, color development and consistency, or occasionally mechanical properties. Molders and part designers generally understand that mechanical property loss can be expected from the addition of colorants. However, problems arise when they grossly underestimate their effect. This chapter addresses several common problems observed with colored engineering resins. These problems include unfilled resin part breakage, glass-reinforced resin part breakage, and colorant induced shrinkage differences. This discussion includes explaining the cause of the problems and some suggested solutions.