Effects of small range color (Pigment) concentration levels on plastic injection molded parts

Color (pigment) concentration levels play a great role in changing the mechanical properties of an injection molded part. Higher concentration levels result in failure during the use of the parts [1]. A general rule of thumb for concentration levels are between 3 to 5% or 5 to 10% is being used across different industries to achieve the required color. The above concentration levels are considered as small range in this manuscript. It is observed during the tensile test conducted on injection molded plastic parts that the small range of concentration levels has an impact on a few mechanical properties including strain at yield and strain at failure. There is no impact on tensile strength, Young's modulus and Poisson's ratio. Hence Product Designers need to assess the impact of these small concentration levels with respect to the base resin and need to specify the acceptable concentration levels in their product drawings or in product specification documents. It is equally important for the molders to verify these concentration levels during molding process.