Hoechst Aktiengesellschaft

Horst Jastrow

Siegfried Noetzel

Edgar Fischer

Wolfgang Strobel

Johann Mixich

Michael Lederer

Horst-Dieter Schuddemage

Harry Barth

Rudolf Uebe

The invention provides finely grained, expandable particles of a styrene homopolymer or copolymer which contain an expanding agent and a flameproofing organic halogen compound as well as, in addition a 2,4-diamino-1,3,5-triazine derivative.

Finely divided expandable styrene polymers

There are disclosed novel flame-proofing agents for plastics, especially for homopolymers and copolymers of styrene and acrylonitrile. These agents are organic compounds containing bromine and one or two phosphinic acid groups. Besides the good flame-retarding properties these compounds have the advantage that they do not adversely affect the shrinking of foamed plastics.

Bromine-containing phosphinic acid esters and flame-resistant plastic

Bromine-containing phosphonic acid esters of the formula ##STR1## in which R represents a halogen-containing linear or branched aliphatic or cycloaliphatic hydrocarbon radical having from 1 to 8 carbon atoms and R' and R' are hydrogen, halogen or alkyl groups having from 1 to 4 carbon atoms which may be closed to form a ring and/or substituted by halogen, at least one substituent being a bromine atom, are suitable as flame retardants for plastic materials, especially polystyrene and styrene copolymers.

Bromine-containing cyclic phosphonic acid esters

Bromine containing telomeric phosphonic acid esters of the formula ##STR1## which are used as flameproofing agent for the preparation of flame-repellent thermoplastic compositions.

Bromine containing telomeric phosphonic acid esters as flame retardant

There is disclosed a process for preparing impact resistant styrene graft copolymers having improved properties, especially a high gloss. They are obtained by polymerizing a solution of an ethylene/propylentercomponent rubber in a mixture of styrene and acrylonitrile in one step (mass polymerization) or two steps (mass/suspension polymerization) in the presence of an organic peroxide and submitting the polymer to a two step extrusion, the first step being carried out at temperatures of from 130.degree. to 240.degree. C, the second step at temperatures of from 200.degree. to 280.degree. C, and providing that during the second extrusion step a quantity of about 0.05 to about 0.5% by weight of the organic peroxide is still present.

Process for preparing impact resistant styrene polymers

The present invention relates to 1,2-dibromoethane phosphonic acid bis-(2,3-dibromopropyl) ester, to a method for preparing the same, and to moldable plastics materials with improved flame retarding characteristics containing 1,2-dibromoethane phosphonic acid bis-(2,3-dibromopropyl) ester as the flame proofing agent.

Process for preparing flame resistant plastics materials

The invention relates to novel impact resistant graft copolymers of a vinyl aromatic on an ethylene/propylene/tercomponent rubber especially characterized by an improved notched impact strength and resistance to atmospheric corrosion, and a process for their preparation. Said copolymers are obtained by a two-step mass/suspension polymerization process characterized by the presence of oxygen, preferably by the presence of air, at a pressure of from 0.05 to 10 atmospheres gauge during the course of the mass polymerization step.

Process for preparing impact resistant polyvinyl aromatics

Bromine-containing phosphonic acid esters of the formula ##EQU1## in which R represents a halogen-containing linear or branched aliphatic or cycloaliphatic hydrocarbon radical having from 1 to 8 carbon atoms and R' and R' are hydrogen, halogen or alkyl groups having from 1 to 4 carbon atoms which may be closed to form a ring and/or substituted by halogen, at least one substituent being a bromine atom, are suitable as flame retardants for plastic materials, especially polystyrene and styrene copolymers.

Bromine containing telomeric phosphonic acid esters of the formula ##EQU1## which are used as flameproofing agent for the preparation of flame-repellent thermoplastic compositions.

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Niederhochstadt, Taunus, Germany

Horst Jastrow