DE1495332A1 - Process for the production of impact-resistant styrene graft polymers - Google Patents

Description

- Patent Department - 1404 / Br ", _A ..

H95332

Our reference: O. Z. 1779

Process for the production of impact-resistant styrene graft polymers

It is known that impact-resistant styrene graft polymers are obtained if solutions of unsaturated, rubber-like homo- or homo- or Copolymers, e.g. styrene / butadiene copolymers in styrene, polymerized or mixtures of these rubber-like products with Manufactures polystyrene by mechanical means. This creates products with better mechanical properties than not modified polystyrene, but they are not transparent and have a matt white color.

It has now been found that impact-resistant styrene graft polymers can advantageously be prepared by polymerizing a solution of styrene / butadiene copolymers in styrene if a styrene / Butadiene copolymer used, the butadiene to more than 80% in the 1,4-cis form contains bound.

co Suitable styrene / butadiene copolymers in which the butadiene

to more than 80% is bound in the 1,4-cis-form, can by

ο Polymerization of mixtures of styrene and butadiene in counter ^ War can be produced by organometallic mixed catalysts.

CD CD .F-

o-> The polymerization of the solution of the styrene / butadiene copolymer in styrene can be carried out in bulk, in suspension or in emulsion. The styrene / butadiene copolymer solutions as obtained after polymerization with organometallic mixed catalysts in inert solvents are expedient,

141/63

-2- f ^ yt) 332 QZ 1779

11/25/63

emulsified, the solvent evaporated, monomeric styrene added and then polymerized under conditions known per se. In addition to the styrene / butadiene copolymer, 0.1 to 30 parts, based on the styrene graft polymer, can be added to the styrene. other unsaturated compounds such as acrylonitrile, methacrylonitrile, vinyl pyridine, alkyl styrenes, acrylic acid esters and methacrylic acid esters, can be added. The second copolymerization component optionally used in addition to styrene can also be used after Suspension or emulsification of the solution of the styrene / butadiene copolymer are added.

The styrene / butadiene copolymer is at in amounts of 0.1 to 50, in particular from 5 to 40%, based on monomeric styrene, used and should contain 1 to 40 percent by weight, in particular 5 to 30 percent by weight, of styrene in addition to butadiene. The butadiene component should be more than 80%, in particular more than 90%, in the 1,4-cis form.

The polymerization is carried out with the aid of initiators which produce free radicals, for example dibenzoyl-, dilauroyl, di-tert. -butyl peroxide or α, α'-Αζο- -diisobutyric acid nitrile, executed. When polymerizing in suspension, common dispersants, e.g. B. polyvinyl alcohol, gelatin, methyl cellulose or polyacrylic acid sodium, emulsifiers commonly used in emulsions, for example sodium dodecylbenzenesulfonate, potassium octyl sulfate or sodium laurate. The polymerization temperature employed depends upon the decomposition temperature of the polymerization used **> activators and is between 40 and 200 ^e C.

Impact-resistant, translucent polystyrenes which are almost transparent in the form of films and which, despite the good mechanical properties, are obtained and contrary to what is usually done when modifying polystyrene

- 3 - OZ 1779

U95332 ²⁵ ' ^{η 63}

with butadiene-containing polymers, the decrease in the softening points observed has almost the same softening points as homopolystyrene.

example

A solution of 55.6 parts by weight of butadiene-styrene-C opolymerisat (10% by weight of styrene, 91% of the butadiene is in the 1,4-cis configuration) in 444.4 parts by weight of monomeric styrene and 2 parts by weight of a, cr Azo-diisobutyric acid nitrile is suspended in 2000 parts by weight of water with the aid of 5 parts by weight of polyvinyl alcohol and ^{heated to 60 °} C. for 20 hours with vigorous stirring.

The polymer is filtered off, washed and dried. the end

Standard rods made from the polymer have a notched bar impact

2 Toughness (DIN 53453) of 9.3 cmkp / cm and a limit bending

tension (DIN 53 452) of 694 kp / cm.

Claims (1)

Claim Process for the production of impact-resistant styrene graft polymers by polymerizing a solution of styrene / butadiene copolymers in styrene, characterized in that a styrene / butadiene copolymer is used which contains butadiene ^ Z ₁ U ₁ pn more than 80 % in the 1 , 4-cis-form bound contains. IfL