Polyoxymethylene with improved acid stability, process for production and use thereof

US5693709A · kind A · utility

Assignee

• Degussa AG · DE

Inventors

• Edwin Nun · Billerbeck, DE
• Stephanie Schauhoff · Frankfurt, DE
• Detlef Arnoldi · Weisenheim am Berg, DE

Key dates

• Filing date: Aug 26, 1996
• Grant date: Dec 2, 1997
• Expiry date: Aug 26, 2016

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08L75/04
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

Polyoxymethylene with improved acid stability, process for production and use thereof. By adding 0.01 to 5 parts of an alkali metal salt of a polybasic acid, for example oxalic acid, citric acid and/or 0.01 to 5 parts of a polyalkylene glycol, for example polyethylene glycol and/or 0.1 to 100 parts of a thermoplastic polyurethane, each related to 100 parts of a polyoxymethylene, this polymer is stabilized against attack by acids, wherein in particular the combination of an alkali metal salt, in particular an oxalate, with small proportions of a thermoplastic polyurethane is advantageous. The proportion of thermoplastic polyurethane may be reduced when the thermoplastic polyurethane has a Shore A hardness of 70 to 96. The weight loss of a stabilized POM under the action of acid may be less than 3% of that of an unstabilized POM. The products are useful when exposed to acidic agents such as irrigation systems, dishwashers, sanitary installations.