Basf Aktiengesellschaft

Wil Duijzings

Norbert Niessner

Michael Breulmann

Sabine Oepen

Norbert G&uuml;ntherberg

Bernhard Czauderna

Graham Edmund Mc Kee

Klaus-Dieter Hungenberg

Norbert Güntherberg

Peter Rossmanith

Hardy Korb

A polybutadiene latex is prepared by a process in which butadiene is polymerized by free radical emulsion polymerization in the presence of initiator and, if required, dispersants and further conventional assistants, the polymerization being carried out in the presence of reactive comonomers in such a way that the heat flow of 43 watt/kg solids content of the polymerization mixture is not exceeded. Owing to the presence of reactive comonomers, the reaction rate at the beginning of the reaction is increased, with the result that an overall flatter heat flow profile is obtained. A preferred reactive comonomer is styrene. Preferably, the process is carried out by a semi-batch procedure in which

Method for producing polybutadiene latex with an optimized thermal current profile

Thermoplastic molding compounds with improved impact resistance

A process for the agglomeration of at least one rubber (A), dispersed in an aqueous phase, by the addition of a dispersion of at least one agglomerating polymer (B) in aqueous phase, in which the agglomerating polymer B used is one containing substantially no free acid groups and the agglomeration is carried out in the presence of at least one basic electrolyte.

Method for agglomerating dispersed rubber

Undesirable changes in shade brought about by low temperatures (Cold Stress Whitening) in impact-modified thermoplastic molding compositions F which comprise at least one elastomeric graft polymer A and at least one thermoplastic polymer B are reduced by adding from 10 to 200 ppm, based on the molding compositions F, of at least one polyorganosiloxane S to the impact-modified thermoplastic molding composition F.

Method for reducing cold stress whitening

The invention relates to a method for producing caoutchouc particles (K) by means of emulsion polymerisation in the presence of an emulsifier and a polymerisation initiator. Said particles contain A) 80 to 100 wt. % of one or more conjugated diene monomers (A) in relation to (K) and B) 0 to 20 wt. % of one or more monoethylenically unsaturated comonomers (B) in relation to (K) in the polymerised form. The inventive method is characterised in that 1) a mixture (M ) containing water and an emulsifier is provided, 2) a mixture (M ) containing one or more monomers in the monomer or polymerised form selected from styrole, &agr;-methylstyrole, butadiene, n-butylacrylate, MMA and acrylnitrile and optionally comonomers is added, 3) polymerisation of the obtained mixture starts in the presence of a polymerisation initiator at temperature of 5 to 95&deg; C., 4) a mixture (M ) containing 0 to 100 wt. % of the comonomers (B) in relation to (B) and 0 to 25 wt. % of the diene monomers (A) in relation to (A) is added, 5) a mixture (M ) containing the (remaining) diene monomers (A) and the (remaining) comonomers (B) is proportioned and polymerised and 6) polymerisation is terminated when there is conversion of more than 90 and less than 95% in relation to the sum of the monomers.

Method for producing caoutchouc particles

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Ludwigshafen, Germany

Wil Duijzings