Abstract: Platelet-shaped multilayered particles wherein the core includes alumina and/or a mixed phase of alumina and silica, the interlayer includes amorphous silica and the sheath includes iron, the iron being present in elemental form and/or in the form of one or more ferriferous compounds selected from the group consisting of ferdisilicide, maghemite, hematite and magnetite. What is disclosed is a preparative process and the use of the particles in the isolation and separation of organic substances or in enzymatic cleavage reactions and in a magnetically stabilized moving bed.

Abstract: There is disclosed an electrically conductive pigment containing 20 to 95% by weight of a component A comprising one or more conductive platelet-like pigments and 5 to 80% by weight of a component B comprising one or more conductive needle-shaped or fibrous pigments.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

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

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: Vulcanisable, elastomeric chloroprene-sulphur copolymers having viscosities of from 60 to 35 MU, strengths of >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.

Abstract: 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.

Abstract: 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; andX represents C.sub.2 -C.sub.10 alkylene.

Abstract: 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.

Abstract: 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.

Abstract: 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:R.sub.1 --S.sub.n --R.sub.1whereinn represents an integer having a value of from 2 to 10, preferably from 3 to 8 and, more particularly, from 4 to 6; and R.sub.1 represents a C.sub.6 -C.sub.14 aryl radical, a C.sub.6 -C.sub.14 aryl-C.sub.1 -C.sub.3 alkyl radical or a heterocycle containing from 1 to 3 hereto atoms, such as N, which may be the same or different and which may optionally be substituted;optionally in combination with a nucleophilic substance, is added to the latex and peptized at from 5.degree. to 100.degree. C. and at pH of from 14 to 3.

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

Abstract: A freeflowing rubber mixture which is stable against coalescence and cohesion comprising a vulcanizable rubber in powder form and a minor amount of an acrylonitrile polymer as a separating agent.

Abstract: This invention relates to xanthogen disulphides of the formula ##STR1## in which R is the same or different and denotes the following groups: ##STR2## WHEREIN X = H, alkyl, aryl, aralkyl or halogenn = 1 to 20,A process for preparing them, a process for polymerizing dienes and .alpha.-olefines in the presence of these particular xanthogen disulphides and to vulcanizable rubber mixtures consisting of an uncross-linked benzene soluble chloroprene homopolymer or copolymer which is prepared in the presence of said xanthogen disulphides.

Abstract: This invention relates to xanthogen disulphides of the formula ##STR1## in which R is the same or different and denotes the following groups: ##STR2## wherein X = H, alkyl, aryl, aralkyl or halogenn = 1 to 20,A process for preparing them, a process for polymerizing dienes and .alpha.-olefines in the presence of these particular xanthogen disulphides and to vulcanizable rubber mixtures consisting of an uncross-linked benzene soluble chloroprene homopolymer or copolymer which is prepared in the presence of said xanthogen disulphides.