Degussa Aktiengesellschaft

Dequssa Ag

Agomer Gesellschaft MIT Beschrankter Haftung

Detlef Arnoldi

Edwin Nun

Stephanie Schauhoff

Wolfgang Leonhardt

Maurizio Ragnetti

Volker Schull

Volker H Schull

Udo Gropp

Beata-Maria Lortz

A method for lowering the residual monomer content of non-vitrified processing aids for thermoplastic polymers involves subjecting an emulsion polymerizate containing methylmethacrylate and, optionally, up to 50% by weight of a comonomer to a post-catalysis step to reduce the residual monomer content followed by a spray-drying step where the residual monomer content is further reduced. The spray-drying step is performed at an exit temperature which is either above the boiling point of methylmethacrylate or if an optional comonomer is present which has a higher boiling point than methacrylate, at a temperature above the boiling point of the comonomer. The resulting product which is suitable for use as a non-vitrified processing aid has a residual monomer content of 100 ppm or less. The processing aid can be used with thermoplastics to form containers, e.g., beverage bottles of PVC, which would not adversely affect odor or taste of the contained food product.

Method of producing non-vitrified processing aid low in residual

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.

Polyoxymethylene with improved acid stability, process for production

The subject invention relates to method for processing crude polyoxymethylene in which the isolation of unstable components from crude polyoxymethylene, such as residual monomers which are at least partly in the form of cyclic formaldehyde derivatives, is effected by treatment of the crude polyoxymethylene with an inert gaseous medium. The method of the invention is characterized in that the gaseous medium contains at least 10 volume % of water vapor, and less than 0.1 volume % of a volatile base, and/or less than 1 volume % of a volatile solvent. In an alternative variant method, the gaseous medium contains at least 10 volume % of water vapor and the treatment occurs at a temperature between 114.degree. C and the softening temperature of the crude polyoxymethylene and at a pressure of less 1.2 .multidot.10.sup.5 Pa.

Method for processing crude polyoxymethylene

A detergent composition with improved dirt-suspending power, method for its production and use of a suitable polycarboxylate for this purpose. The novel detergent contains, in addition to the customary components such as surfactant, calcium-binding silicate, etc., at least 1% by weight of a polycarboxylate with the schematic structure (X, Y, Z) in which X stands for ##STR1## Y for ##STR2## and Z for

Detergent composition and method of use with surfactant, silicate, and

A processing agent for polyvinyl chloride and other thermoplastic polymers. The processing agent is a copolymer which contains a monomer whose homopolymer has a T.sub.g .gtoreq.65 C. and contains 3 to less than 75% by weight of a comonomer which has a C.sub.8 -C.sub.22 alkyl component. The alkyl component should be apportioned in such a fashion that the transmission of the copolymer in ethyl acetate is at least 90% in the case of a 10% solution.

Processing agent having a C.sub.8 -C.sub.22 component

By adding melamine cyanurate, polyoxymethylene is stabilized against acid attack, wherein in particular as little as under 3 parts of MCA per 100 parts of POM are effective. The weight loss of a stabilized POM under the action of acid may be less than 3% of that of an unstabilized POM. The product is useful in products which are exposed to acidic agents such as irrigation systems, dishwashers, sanitary installations.

Polyoxymethylene having improved acid stability

Polyoxymethylene molding materials having improved thermal stability and reduced formaldehyde emission consisting essentially of a polyoxymethylene as the main component and containing in addition, relative in each instance to the weight of the polyoxymethylene, 0.1 to 10% by weight of an endocopolymerizate, 0.05 to 3% by weight of a phenolic antioxidant, 0 to 5% by weight carbon black and 0 to 3% by weight of further additives customary in polyoxymethylene molding materials.

Growing community of inventors

Weisenheim am Berg, Germany

Detlef Arnoldi