ABSTRACT
Blow molding is a very complex process because a large number of properties are balanced and interdependent. In general, blow molding requires that plastic has high stiffness, good impact properties, good environmental stress cracking resistance, and processes consistently. Most plastic parts require specific physical performance properties that provide a benefit over an alternate material. When selecting resin for a part similar to an existing part, the obvious choice is to start with the resin, if known. Cost should be the last consideration in the material selection process. Most often data sheets for blow molding resins show melt index, density, tensile, elongation, and modulus. Tensile strength is the extensible resistance to breakage of a material expressed in force per cross-sectional area. Elongation is a measure of a material's ability to flow under force in a given time period. Tensile yield is another property measured during the tensile test.
