M&t Chemicals, Inc.

Robert D Dworkin

Adam J Ejk

William A Larkin

The combination of a conventional antimony- or bismuth-containing heat stabilizers with certain aromatic esters or aryloxides containing boron, phosphorus, silicon, antimony, tin or zinc interacts synergistically to provide an unexpectedly high level of heat stability to halogen-containing polymers such as polyvinyl chloride (PVC). In addition the aromatic ester or aryloxide inhibits spontaneous degradation of the heat stabilizing component in the presence of heat and/or light.

Synergistic heat stabilizer compositions containing an antimony or a

This invention relates to novel organotin compounds containing at least one sulfur atom that is bonded exclusively to tin or to tin and hydrogen. The compounds are derivatives of mercaptoalkanols, which are present as the free alcohols, as esters of polycarboxylic acids, esters of acids containing specified non-metallic elements or as alkoxides of specified metallic elements. The compounds are effective catalysts for a variety of reactions and impart heat stability to halogen-containing resins.

Organotin mercaptoalkanol esters and alkoxides containing sulfide groups

The combination of a conventional antimony--or bismuth-containing heat stabilizers with certain aromatic esters or aryloxides containing boron, phosphorus, silicon, antimony, tin or zinc interacts synergistically to provide an unexpectedly high level of heat stability to halogen-containing polymers such as polyvinyl chloride (PVC). In addition the aromatic ester or aryloxide inhibits spontaneous degradation of the heat stabilizing component in the presence of heat and/or light.

Organotin derivatives of mercaptoalcohol esters that correspond to the general formula ##STR1## wherein R and R' are hydrocarbon and m is 2 or 3, are prepared by sequentially reacting a monoorganotin trihalide with stoichiometric amounts of a base, a mercaptoalcohol, an alkali metal sulfide or disulfide and a carboxylic acid or an ester thereof. The present method offers advantages over the prior art, which teaches reacting an esterified mercaptoalcohol with an organotin halide, oxide or organostannoic acid. Compounds wherein R' is n-heptyl are unique in that they do not exhibit the disagreeable odor that characterizes this class of compounds.

Method for preparing organotin compounds

Organotin derivatives of mercaptoalcohol esters that correspond to the general formula ##STR1## wherein R and R' are hydrocarbon, m is 2 or 3, and p is 1 or 2 are prepared by sequentially reacting a quantity of a monoorganotin trihalide, a diorganotin dihalide or an equimolar mixture of a mono- and a diorganotin halide containing n moles of halogen with n-2 equivalent weights of a base, n-2 moles of a mercaptoalcohol, 0.5 mole of an alkali metal sulfide when p is 1 or an alkali metal disulfide when p is 2, for every mole of tin present and n-2 moles of an carboxylic acid or ester thereof. The present method offers advantages over the prior art, which teaches reacting an esterified mercaptoalcohol with an organotin halide, oxide or organostannoic acid. Compounds wherein R' is n-heptyl are unique in that they do not exhibit the disagreeable odor that characterizes this class of compounds.

Method for preparing bis(organotin mercaptoalkanol ester) sulfides

Organotin derivatives of mercaptoalcohol esters corresponding to the general formula ##STR1## WHEREIN R and R' are hydrocarbon, m is 2 or 3 and q is 1 or 2 are prepared by reacting a mercaptoalcohol of the formula HS(CH.sub.2).sub.m OH with a diorganotin oxide, organostannoic acid or an anhydride of said acid in an aqueous medium and subsequently esterifying the reaction product with the desired carboxylic acid, R'COOH, or an ester thereof. The present method offers advantages over the prior art, which teaches reacting an esterified mercaptoalcohol with an organotin compound. Compounds wherein R' is n-heptyl are unique in that they do not exhibit the disagreeable odors that characterize this class of compounds.

The presence of free carboxylic acids containing from 8 to 20 carbon atoms or the anhydrides of these acids inhibits the rate of heat induced discoloration exhibited by certain polymer formulations containing as a heat stabilizer the reaction product of a carboxylic acid with a stoichiometric excess, based on the number of carboxyl groups present, of a diorganotin oxide. The free acids are virtually ineffective heat stabilizers for these polymers in the absence of the aforementioned reaction product. The polymers which can be stabilized include vinyl chloride polymers and acrylonitrile-butadiene-styrene terpolymers.

Method for stabilizing vinyl chloride polymers

Diorganotin carboxylates containing more than 1 mole of tin for every 2 moles of carboxylic acid ##STR1## residues are prepared by a solid state reaction between a diorganotin oxide and a dicarboxylic acid anhydride. Depending upon the temperature of the oxide-anhydride mixture, the reaction is substantially complete in from less than 1 to up to 48 hours and produces no by-products.

One step method for preparing non-stoichiometric diorganotin

Cellular vinyl chloride polymers are prepared in the presence of a blowing agent and a diorganotin dimercaptide such as di-n-butyltin bis(dodecyl mercaptide). These organotin compounds are unique in that they activate the blowing agent to achieve maximum gas evolution at conventional processing temperatures while imparting a superior level of heat stability to the polymer. The dimercaptide is preferably employed in combination with a specified organotin derivative of a carboxylic acid, alcohol or phenol and/or metal salts of carboxylic acids containing between 4 and 18 carbon atoms wherein the metal is selected from Group IIB of the Periodic Table.

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Old Bridge, NJ, United States of America

Robert D Dworkin