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Glossary » Materials » Polymers » Polyacetal » Impact Modified

Impact Modified Acetal is a subcategory of Polyacetal. The additative is added during the manufacturing process. Its elastic modulus ranges from 190 to 350 MPa. Its flexural modulus ranges from 50 to 100 MPa. Its tensile strength ranges from 6500 to 8400 MPa at break. Its flexural strength ranges from 5800 to 10000 MPa. Its compressive strength ranges from 7600 to 11900 MPa. Its Izod Impact strength ranges from 2 to 17 J/cm. Its elongation at break ranges from 60 to 200 %. Its hardness ranges from 58 to 79 Rockwell M. Its specific gravity ranges from 1.32 to 1.39. Its coefficient of thermal expansion ranges from 92 to 117 x 10^-6/°C. Its molding pressure ranges from 6 to 12 MPa.

Polyacetal, also known as Acetal, is a thermoplastic. Common trade names are Delrin and Ultraform. homopolymer It is a lubricious, strong, and resistant to creep and fatigue. It has good dimensional stability and relatively high abrasion and chemical resistance. Acetal is commonly used in quality toy parts, handles, knobs, and bearing parts. Delrin is approved by FDA for use in the food industry. Acetal resins were commonly used in the plumbing industry. However, they are sensitive to chlorine which leads to cracks in acetal plumbing fittings. The widespread failure of acetal moldings in potable and hot water supplies resulted in one of the largest class actions in the USA when acetal plumbing fittings cracked and caused floods of many homes in many states.