Bayer Aktiengesellschaft

Wilhelm Gobel

Rudiger Musch

Eberhard Muller

Wolfgang Konter

Werner Obrecht

Peter Wendling

Gottfried Pampus

Rudolf Mayer-Mader

Rudiger Schubart

Peter R Muller

Rudolf Casper

Heinrich Alberts

Manfred Beck

Joachim Thormer

Ulrich Eisele

Gerhard Hohmann

Wilfried Nolte

Jochen Schnetger

Jean Mirza

Gerhard Giersiepen

Toluene-soluble, sulphur-modified polychloroprene is obtained by emulsion copolymerization of chloroprene, sulphur and optionally further monomers which are copolymerizable with chloroprene and sulphur using a peroxy activator and subsequent working-up by stabilizing, stopping, degassing and isolating without separate peptization, in that polymerization is carried out in the presence of dithiocarbamates and/or xanthogenates and the activator is metered in continuously or batch-wise during the course of polymerization.

Process for the production of toluene-soluble, sulphur-modified

The invention relates to a polychloroprene rubber which shows advantages over the prior art in the sum total of its performance properties, namely vulcanization rate, tensile strength, elongation at break, modulus, tear propagation resistance and thermal stability of the vulcanizate.

Polychloroprene mixtures

An improved process for the preparation of polychloroprene by the emulsion (co)polymerization of chloroprene and optionally other monomers capable of copolymerization with chloroprene, using a peroxo activator, and subsequent working up of the product by stopping the reaction, stabilizing, degassing and isolating the product, characterized in that polymerization is carried out in the presence of dithiocarbamates and/or xanthates and 0 to 0.5% by weight of sodium .beta.-anthraquinone sulphonate.

Polymerization of chloroprene with xanthates and dithiocarbamates

An elastomeric mass of polychloroprene sol and polychloroprene gel in proportions in the range of 95:5 to 25:75% by weight in which the polychloroprene sol is free from sulphur and the polychloroprene gel used is a sulphur-containing gel with xanthate or carbamate functions has better processing characteristics than the pure sol component without the expected deterioration in the mechanical properties of the vulcanisates prepared from the mass.

Elastomeric mass of polychloroprene sol and polychloroprene gel

Polychloroprene rubbers having favorable processing behavior and excellent properties are obtained if mono-, di- or trichlorosubstituted polyisobutylene is added as plasticizer before vulcanization.

Vulcanizable polymer mixtures, their production and use and vulcanizates

A process for the production of storable polychloroprene having reduced tackiness on mixing rolls by the continuous polymerization of chloroprene and, optionally, up to 50%, by weight, of a monomer copolymerizable with chloroprene in aqueous alkaline emulsion in the presence of emulsifiers and radical initiators at temperatures of from 0.degree. to 70.degree. C., followed by isolation, characterized in that from 90 to 150 parts, by weight, of water, from 2.5 to 4.0 parts, by weight of a potassium salt of disproportionated abietic acid (based on acid), from 0.3 to 1.0 parts, by weight, of a condensation product of naphthalene sulphonic acid and formaldehyde and from 0.2 to 1.5 parts, by weight, of potassium hydroxide, all the quantities being based on 100 parts, by weight, of monomer, are used for the polymerization reaction.

Continuous polymerization of chloroprene

Solid polychloroprene mixtures consisting of sol and gel polymer, wherein the sol component consists of a copolymer of chloroprene and from 0.75 to 0.32% by weight of sulphur, based on the total quantity of unsaturated compounds of the sol polychloroprene, and the gel component consists of a copolymer of chloroprene, from 0.4 to 1.0% by weight of sulphur, based on the total quantity of unsaturated compounds of the gel polychloroprene and from 7.5.times.10.sup.-3 to 3.0.times.10.sup.-2 mols, based on 100 g of the total quantity of monomer of the gel polychloroprene, of a compound corresponding to the general formula ##STR1## wherein R.sub.1 and R.sub.2 each represents a hydrogen atom or C.sub.1 -C.sub.4 alkyl group, and X represents a C.sub.2 -C.sub.10 alkylene group, are suitable for the production by extrusion and by calandering of rubber articles which may be subjected to high strains.

Polychloroprene mixtures and the use thereof

Vulcanizable, elastomeric chloroprene/sulfur copolymers having viscosities of from 60 to 35 ME, strengths of greater than 20 MPa and sulfur contents of from about 0.3 to 0.45% by weight are obtained by polymerizing chloroprene in the presence of from 0.05 to 0.40% by weight of sulfur to form a latex I, polymerizing chloroprene in the presence of from 0.5 to 1.5% by weight of sulfur to form a latex II, mixing latices I and II, optionally together with other sulfur-modified polychloroprene latices, in a ratio of from 4:1 to 1:4 (based in each case on solids) and peptizing the mixture, followed by working up to form the solid rubber, the percentages quoted being based on the quantity of monomer.

Production of sulfur-modified solid chloroprene rubbers

Vulcanisable, elastomeric chloroprene-sulphur copolymers having viscosities of from 60 to 35 MU, strengths of &gt;20 MPa and sulphur contents of from about 0.5 to 0.7%, by weight, in the batch are obtained by polymerising chloroprene in the presence of from 0.10 to 0.35%, by weight, of sulphur to form a latex I, polymerising chloroprene in the presence of from 0.50 to 1.00% by weight, of sulphur to form a latex II, mixing latices I and II in a ratio of from 4:1 to 1:4 (based in each case on solids), optionally together with other sulphur-modified polychloroprene latices, the mixture is peptised and worked-up to form the solid rubber, the percentages quoted being based on the quantity of monomer.

Process for the production of sulphur-modified solid chloroprene rubbers

This invention relates to a polychloroprene elastomer distinguished by good processing properties and high tensile strength in the form of a polychloroprene mixture containing a sol polymer and a gel polymer in a ratio, by weight, of from 1:4 to 9:1, characterized in that both polymers have been produced in the presence of from 2.5 to 4.0 parts, by weight, of the potassium salt of disproportionated abietic acid (expressed as acid), from 0.3 to 1.0 part, by weight, of a condensation product of naphthalene sulphonic acid and formaldehyde and from 0.1 to 1.5 parts, by weight, of potassium hydroxide, based in each case on 100 parts, by weight, of monomer, and in that the gel polymer is a copolymer of chloroprene and from 1.5 to 2.5 mole percent, based on total monomer, of a diester corresponding to the following general formula: ##STR1## wherein R.sub.1 and R.sub.2 represent hydrogen, chlorine or C.sub.1 -C.sub.4 alkyl; and

Mixtures of chloroprene polymers and the production thereof

A process for the production of polychloroprene mixtures of sol and gel polymers in a ratio, by weight, of rom 1:4 to 9:1, the gel polymer being produced by radical emulsion polymerization from chloroprene in the presence of 4 to 10% by weight of water soluble disproportionated abietic acid, and the sol polymer being produced by radical emulsion polymerization of chloroprene in the presence of not more than 3.5% by weight of a water soluble disproportionated abietic acid with the polychloroprene mixture containing at most 3.8% of said acid.

Process for the production of chloroprene polymer mixtures

Vulcanizable, elastomeric, sulphur-modified polychloroprene rubbers having improved properties are obtained by adding up to 40%, by weight, of SBR latex (solids, based on total solids) before working-up and before or after peptization.

Production of sulphur-modified polychloroprene rubbers

By adding substances corresponding to the following general formula I ##STR1## in which X=O, S or N--R.sub.5 ; R.sub.1 =hydrogen, C.sub.1 -C.sub.19 -alkyl, C.sub.2 -C.sub.19 -alkenyl, phenyl, C.sub.1 -C.sub.4 -alkylene phenyl, C.sub.5 -C.sub.12 -cycloalkyl or C.sub.5 -C.sub.12 -cycloalkenyl; R.sub.2 =hydrogen, C.sub.1 -C.sub.19 -alkyl, C.sub.2 -C.sub.12 -alkenyl, phenyl or C.sub.1 -C.sub.4 -alkylene phenyl; R.sub.3 =hydrogen, C.sub.1 -C.sub.19 -alkyl, C.sub.2 -C.sub.19 -alkenyl, phenyl, C.sub.1 -C.sub.4 -alkylene phenyl, acryl formyl or acetyl; R.sub.4 and R.sub.5 =same or different, C.sub.1 -C.sub.19 -alkyl, C.sub.2 -C.sub.19 -alkenyl, phenyl, C.sub.1 -C.sub.4 -alkylene phenyl, acryl, C.sub.5 -C.sub.12 -cycloalkyl or C.sub.5 -C.sub.12 -cycloalkenyl; R.sub.4 and R.sub.5 may also form a C.sub.4 -C.sub.7 -ring which may optionally contain an oxygen atom in ether form and the radicals R.sub.1 and R.sub.2 may form a C.sub.5 -C.sub.12 -alkylene bridge or a C.sub.5 -C.sub.12 -alkenylene bridge, the radicals R.sub.1 and R.sub.4 may form a C.sub.2 -C.sub.9 -alkylene bridge and the radicals R.sub.1 and R.sub.3 may form a C.sub.3 -C.sub.10 -alkylene bridge; where R.sub.1 and R.sub.2 are attached, the ring formed may be bridged by a C.sub.1 -C.sub.4 -alkylene bridge and the ring systems formed may be substituted by the radical R.sub.6 which represents hydrogen, C.sub.1 -C.sub.5 -alkyl or C.sub.2 -C.sub.5 -alkenyl, in quantities of from 0.05 to 3% by weight, based on 100 parts by weight of monomer, to the aqueous emulsion polymerization of chloroprene at the beginning of the reaction, during or after polymerization, but at the latest before the residual monomers are removed, high-viscosity polychloroprenes characterized by excellent processing behaviour and product properties are obtained.

Process for the production of high molecular weight polychloroprene and

A process for the production of storable 2-chloro-1,3-butadiene/sulphur copolymers by peptization using sulphur containing petizing agents, wherein a compound corresponding to the following general formula:

Process for the production of storable 2-chloro-1,3-butadiene/sulfur

The molecular weight of chlorine containing elastomers are increased by adding sulphur compounds before or during the chlorination of elastomers.

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Leverkusen, Germany

Wilhelm Gobel