Polyoxymethylene

Acetal Delrin Sheet Acetal resins (polyoxymethylene or POM) are engineering thermoplastics based on formaldehyde polymerization technology. Acetal resins have high tensile strength, stiffness, resilience, fatigue endurance, a low coefficient of friction against metals, acetals and other plastics and moderate toughness. The Acetal sheet has high resistance to organic solvents, excellent dimensional stability, a low coefficient of friction and outstanding abrasion resistance among thermoplastics. Acetals’ resistance to creep is excellent. Moisture, lubricants and solvents including gasoline and gasohol have little effect on this property, which is important in parts incorporating self-threading screws or interference fits. Good electrical properties qualify these materials for electrical applications requiring long-term stability. Acetal copolymers retain much of their toughness through a broad temperature range and are among the most creepresistant of the crystalline thermoplastics. A low moisture absorption characteristic permits molded parts to serve reliably in environments involving humidity variations.     Features ·         Excellent dimensional stability ·         Continuous use temperature of 180°F ·         Porosity free ·         Consistent properties in wet or moist environments ·         Very low moisture absorption ·         Excellent electrical properties ·         Easy to machine to close tolerances ·         Natural and Black are FDA & USDA compliant Applications ·         Bushings and bearings ·         Rollers and gears ·         Valves and manifolds ·         Scraper blades ·         Wear strips and pads ·         Jigs and fixtures ·         Electrical components ·         Parts which operate in water between 60 to 90C Certifications ·         ASTM POM 0211, D6778 ·         FDA21 CFR 177.2470 Properties  Standard Unit  Result  mechanical property Density  ASTM D792 g/cm3 1.43 Tensile strength  ASTM D638 Mpa 100 ultimate elongation ASTM D638 % 10 bending strength  ASTM 790 Mpa 150 bending  modulus  ASTM 790 Mpa 4500 hardness  ASTM D2240 D 85 Impact strength  ASTM D256 J/M 100 Thermal properties  Melting poing  DSC ℃ 190 working Temp. ASTM D648 ℃ 140 Permanent Temp. - ℃ 120 Short-period Temp. - ℃ 150 Pyroconductivity  DIN 52612-1 W/(K-M) 0.31 dilatation coefficient  ASTM D696 10-5-1/K 6 electrical property  dielectric strength  ASTM D150 KV-mm 22 dielectric loss coefficient  ASTM D150 - 0.005 Volume resistance ASTM D257 Ω.cm 1014 surface resistance  ASTM D257 Ω 1016 dielectric constant  ASTM D149 - 3.9 Chemical properties  Water absorption 23℃ 60%RH % 0.35 Acid resistance 23℃ 60%RH   + Alkali resistance     + Resistance to acid and alkali water     + Chloric acid alkali resistance     0 Resistant to aromatic compounds     + The ketone resistance 23℃ 60%RH   + Water resistance 23℃ 60%RH   + Others properties  combustibility UL 94   HB paste  -   + Non-toxic harmless EEC 90/128 FDA   + friction coefficient DIN 53375   - uvioresistant -   0