Wacker Polymer Systems Gmbh & Co. Kg

Peter Weiler

Abdulmajid Hashemzadeh

Peter Ball

Klaus Kohlhammer

Ulf Dietrich

Thomas Lehmann

Particulate materials are cold molded by preheating a binder and the material to be bound to a temperature of from 160 to 240&deg; C., and then press molding at a temperature less than 80&deg; C. and at a pressure of from 1 to 120 bar to give a molding, wherein the binder contains a polymer powder or aqueous polymer dispersion thereof, the polymer having a glass transition temperature Tg greater than 80&deg; C. and a complex viscosity less than 15,000 Pa&middot;s at 190&deg; C., and derived from one or more comonomer units from the group of vinyl esters of optionally branched C alkylcarboxylic acids, (meth)acrylic esters of optionally branched C alcohols, dienes, olefins, vinylaromatics, and vinyl halides. The moldings exhibit excellent properties including resistance to sagging at elevated temperatures, and are recyclable.

Process for the cold molding of particulate materials

The invention provides for the use of non-copolymerizable hydroperoxides of the formula R&mdash;O&mdash;O&mdash;H as regulators in the free-radically initiated polymerization of ethylenically unsaturated monomers, where R is H, a C -C -alkyl radical, a C -C -aralkyl radical or a saturated or unsaturated carbocyclic or heterocyclic ring having from 3 to 18 carbon atoms, and may be substituted or unsubstituted.

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Geretstried, Germany

Peter Weiler