Bayer Aktiengesellschaft

Wolfgang Konter

Rudiger Musch

Wilhelm Gobel

Eberhard Muller

Gerhard Hohmann

Peter Wendling

Gottfried Pampus

Rudolf Casper

Hans-Dieter Block

Josef Witte

Peter R Muller

Ulrich Eisele

Peter Vehlewald

Wilfried Nolte

Ludwig Mott

The polymerization of chloroprene leads to non-colored products when a mixture of 2.0 to 5.0% by weight of a salt of disproportionated abietic acid and 0.1 to 1.0% by weight, in each case relative to the total amount of monomer, of a compound of the formula ##STR1## in which R.sub.1 and R.sub.2, independently of one another, denote hydrogen or CH.sub.3,

Process for polymerization of chloroprene

Storage-stable polychloroprene is obtained, using a polymerization initiator comprising a mixture of

Polymerization of chloroprene

Gel-free polychloroprene is obtained, at high monomer conversions, using a polymerization initiator comprising sodium dithionite or a mixture of sodium dithionite with formamidinesulphinic acid or with potassium peroxydisulphate or with formamidinesulphinic acid and potassium peroxodisulphate or with potassium peroxodisulphate and sodium anthraquinon-.beta.-sulphonate or with formamidinesulphinic acid and potassium peroxodisulphate and sodium anthraquinone-.beta.-sulphonate, and in the presence of oxygen and a chain transfer agent when 30 to 90% of the initiator is present at the commencement of polymerization and the remainder is added in portions during the polymerization, only further sodium dithionite being added at a conversion &gt;60% in the case of an initiator combination, and when 20 to 80% by weight of the total amount of chain transfer agents is present before or at the commencement of polymerization and the remaining amount is added in one or more parts at monomer conversions of greater than 20%.

An improved process of polymerizing an aqueous emulsion of chloroprene monomer stabilized with phenothiazine wherein polymerization is initiated in the presence of phenothiazine stabilizer and molecular oxygen with a polymerization initiator comprising sodium dithionite.

Polymerizing phenothiazine stabilizer chloroprene in the presence of an

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

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

The instant invention relates to graft polymers of vinyl phosphonic acid esters, optionally together with nitrogen-containing polymerizable vinyl compounds, on polyalkylene glycols and to a process for their production. The polymers so produced necessarily contain phosphorus and, optionally, nitrogen in the molecule. The polymers are rendered flameproof by the phosphorus and, in addition, self-extinguishing by the nitrogen.

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Neuss, Germany

Wolfgang Konter