Bayer Aktiengesellschaft

The Firestone Tire & Rubber Company

Hans-Wilhelm Engels

Daniel F Graves

Thomas Scholl

Pramod Gupta

Ulrich Eisele

Werner Obrecht

Rudiger Schubart

Hermann-Josef Weidenhaupt

Peter Wendling

Joachim Thormer

Wilfried Nolte

Hansjurgen Rabe

Ulrich Eholzer

Christian Konig

Stefan Kelbch

Chiraranjan Podder

R&uuml;diger Schubart

Bernd Stollfuss

Hans-Jurgen Rabe

Zinc dithiocarbamates are obtained in especially readily filterable form and high purity when zinc salts are first added, in aqueous solution, to the secondary amines underlying the zinc carbamates, so that a zinc salt complex of the amines is formed, and carbon disulfide and then sodium hydroxide solution are then introduced, with stirring, into the aqueous suspension so obtained, the temperatures being maintained in the range from room temperature to the boiling temperature of carbon disulfide until the reaction has completely finished.

Process for the preparation of zinc dithiocarbamates

New vulcanization accelerators, corresponding to the formula ##STR1## are particularly suitable for the production of vulcanized rubbers modified with lateral polar groups.

Vulcanization accelerators suitable for the introduction of polar

Vulcanizable rubber compositions are disclosed which contain partial polycarboxylic acid esters or their salts. Vulcanizates obtained from the compositions are readily processible and are found to have reduced compression set and high tension values, in particular after ageing by heat.

Vulcanizable rubber compositions containing salts of partial carboxylic

The present invention relates to the use of nucleus-substituted 4-hydroxyphenyl propionic acid compounds for stabilizing organic polyisocyanates.

Stabilization of organic polyisocyanates

The rubber vulcanizates according to the invention, which are produced using certain carboxyalkyl oligosulfides, are distinguished by improved hysteresis behavior; their mechanical properties remain substantially unaffected.

Rubber vulcanizates having improved hysteresis behavior

Rubber mixtures containing so-called 'pre-crosslinked' polychloroprene give vulcanizates having an improved combination of low rolling resistance and low abrasion.

Rubber mixtures containing sulfur-modified polychloroprene gel

The elminination of sulfur from bis-(dialkoxythiophosphoryl)-tetrasulfides to bis-(dialkoxythiophosphoryl)-trisulfides on certain silicate fillers, carbon black and aluminium oxide is quantitative.

Process for the production of bis-(dialkoxythio-phosphoryl)-trisulfides

The present invention relates to a method for stabilizing a polyether polyol having a molecular weight of from about 300 to about 10,000 comprising adding 3,5-di-tert-butyl-4-hydroxyphenylpropionic acid as an antioxidant stabilizer, optionally in combination with other antioxidants, to said polyether polyol. This invention further relates to polyols stabilized by the method of this invention and to stabilized polyurethanes prepared from such stabilized polyols.

Use of 3,5-di-tert-butyl-4-hydroxyphenylpropionic acid for stabilizing

It now has been found that uncured rubber composition comprising rubbers having an unsaturated carbon chain and at least one carbon black can be improved by including therein, a minor property-improving amount of at least one aromatic heterocyclic di-N-oxide compound of the partial formula ##STR1## wherein the depicted carbon atoms are part of an optionally substituted aromatic ring, and R.sup.1 and R.sup.2 are each independently hydrogen, hydrocarbyl, halohydrocarbyl, hydrocarbyloxy, hydrocarbyl sulfonyl, hydrocarbyl thio, hydrocarbylsulfoxidyl, halogen, amino,

Rubber compositions modified with heterocyclic di-N-oxides

It now has been found that the properties of rubber compositions comprising rubbers having an unsaturated carbon chain can be improved by including therein, a minor property-improving amount of at least one hydroxy-benzimidazole oxide compound of the formula ##STR1## wherein R is hydrogen, or a halogen, hydroxyl, lower acyl, lower hydrocarbyl, lower hydrocarbyloxy, lower hydrocarbylthio, carboxyl, cyano, amino, amide or --C(O)-- lower hydrocarbyl group, and R' is hydrogen, or a lower hydrocarbyl, lower hydrocarbyl amide, carboxamide carboxy acid, carboxy ester, or aryl group. When vulcanizates are prepared from such rubber compositions containing one or more fillers, the vulcanizates exhibit reduced low strain hysteresis and a high electrical resistivity. In another aspect of the invention, a filled vulcanizate made by vulcanizing uncured compositions of the type described above and containing a filler, particularly carbon black, is improved in filler interaction, hysteresis, modulus, compression set and resiliency. Rubber articles and portions thereof such as tires, hoses, springs, belts, treads, sidewalls and the like can be made utilizing the improved filled vulcanizates of the invention.

Rubber compositions modified with hydroxy-benz-imidazole oxides

It now has been found that the properties of filled rubber compositions comprising rubbers having an unsaturated carbon chain can be improved by including therein, a minor property-improving amount of at least one 1,3-dihydroxy-benzimidazolinone or derivative compound of the formula ##STR1## wherein R is hydrogen, or a halogen, hydroxyl, lower hydrocarbyl, lower hydrocarbyloxy, lower hydrocarbylthio, lower hydrocarbyl nitrile, carboxyl, cyano, nitro, amino, amide or --C(O)--R'' where R'' is an aryl or a lower hydrocarbyl group; each R' independently is H, lower alkyl, acyl, CONR'2 or CONHR' where R' is alkyl or aryl. When vulcanizates are prepared from such uncured rubber compositions, the vulcanizates exhibit reduced low strain hysteresis and a high electrical resistivity. In another aspect of the invention, a filled vulcanizate made by vulcanizing uncured compositions of the type described above and containing a filler, particularly carbon black, is improved in filler interaction, hysteresis, modulus, compression set and resiliency. Rubber articles and portions thereof such as tires, hoses, belts, springs, tread, sidewalls and the like can be made utilizing the improved filled vulcanizates of the invention.

Growing community of inventors

Kerpen, Germany

Hans-Wilhelm Engels