Halogen containing polymer composition with tin stabilizer and co-stabilizer

Abstract

The present invention relates to the thermal stabilization of halogen containing polymer compositions. More particularly the invention relates to a tin stabilizer composition for chlorine containing polymers, and more specifically a composition comprising a mono alkyltin compound as major compound of the tin stabilizer composition and a co-stabilizer. The present invention relates as well to the use of a mono alkyl tin compound as major compound of the tin stabilizer and a co-stabilizer as heat stabilizers for processing chlorine containing polymer composition.

1 . A thermoplastic processable stabilized polymer composition comprising
 a) at least one halogen containing polymer,   b) at least one tin based stabilizer composition comprising a mono alkyl tin compound of formula RSn(T) 3  which represents at least 85 wt % of the tin based stabilizer composition; and,   c) at least one co-stabilizer,   
       wherein the co-stabilizer presents at least 0.65 phr with respect to the halogen containing polymer and wherein the co-stabilizer c) is chosen from an organic polyol with at least three hydroxyl groups, an organic ester with a molecular weight of at least 172 g/moL or an ester of an organic polyol said ester having at least three free hydroxyl groups, and mixtures thereof. 
     
     
         2 . The thermoplastic processable stabilized polymer composition according to  claim 1 , wherein the halogen containing polymer is a chlorine containing polymer. 
     
     
         3 . The thermoplastic processable stabilized polymer composition according to  claim 2  wherein the tin based stabilizer composition comprises from 85 wt % to 99.99 wt % of at least one monoalkyltin compound of formula RSn(T) 3 , in which R is a C 1 -C 10  alkyl, and T is a ligand. 
     
     
         4 . The thermoplastic processable stabilized polymer composition according to  claim 3  wherein the tin based stabilizer composition comprises
 from 0.001 wt % to 10 wt %, of at least one di-alkyltin compound of formula R 2 Sn(T) 2 ; 
 from 0.001 wt % to 5 wt % of at least one tri-alkyltin compound of formula R 3 Sn(T); and 
 from 0 wt % to 5 wt % of one or more impurities. 
 
     
     
         5 . The thermoplastic processable polymer composition according to  claim 2 , wherein the chlorine containing polymer is chosen from among polymers or mixtures of polymers chosen from: polyvinyl chloride, polyvinylidene chloride, chlorinated polyvinyl chloride, post-chlorinated polyvinyl chloride, and copolymers formed by the polymerization of a vinyl halide monomer with up to 40% of a comonomer; and wherein the comonomer is chosen from: vinyl acetate, vinyl butyrate, vinylidene chloride, propylene, methylmethacrylate, or a chlorine-containing polymer containing other polymers. 
     
     
         6 . The thermoplastic processable polymer composition according to  claim 5 , wherein the chlorine containing polymer is chosen from PVC homopolymer, copolymer, or mixtures thereof. 
     
     
         7 . The thermoplastic processable polymer composition according to  claim 1 , wherein R of the monoalkyl tin compound of b) is chosen from: methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, 2-ethylhexyl, iso-octyl, and decyl, preferably R is methyl, n-butyl, 2-ethylhexyl, n-octyl, or n-decyl. 
     
     
         8 . The thermoplastic processable polymer composition according to  claim 1 , wherein T of the monoalkyl tin compound of b) is chosen from: thioglycolate esters, 2-ethylhexylthioglycolate esters, iso-octylthioglycolates, iso-butylthioglycolates, thioglycolate, hydroxyl, carboxylates, maleates, diketonates and alcoholates. 
     
     
         9 . The thermoplastic processable polymer composition according to  claim 1 , wherein the co-stabilizer is present at least at 0.75 phr. 
     
     
         10 . The thermoplastic processable polymer composition according to  claim 1 , wherein the polyol has a molecular weight M of at least 78 g/mol. 
     
     
         11 . The thermoplastic processable polymer composition according to  claim 1 , wherein the polyol has a molecular weight M of less at least 92 g/mol and less then 3000 g/mol. 
     
     
         12 . The thermoplastic processable polymer composition according to  claim 1 , wherein the organic ester is presented by the general formula R1-COO-R2 and R1 and R2 are a linear, branched or cyclic alkyl radical having from 4 to 25 carbon atoms (C 4 -C 25  alkyl), alkenyl radicals, aryl radical or alkylaryl radicals. 
     
     
         13 . The thermoplastic processable polymer composition according  claim 1 , wherein the organic ester is the reaction product of an organic acid and monofunctionel difunctionel aliphatic alcohols. 
     
     
         14 . The thermoplastic processable polymer composition according to  claim 1 , wherein the co-stabilizer is an organic ester of a polyol, said ester having at least three hydroxyl groups. 
     
     
         15 . The thermoplastic processable polymer composition according to  claim 1 , wherein the co-stabilizer is an organic ester of a polyol, said ester having at least three free hydroxyl groups and at least one hydroxyl group is on an acid part of the organic ester of the polyol. 
     
     
         16 . The thermoplastic processable polymer composition according to  claim 15 , wherein the ester of the polyol has no insaturations. 
     
     
         17 . A method of using a tin based stabilizer composition, wherein the stabilizer composition comprises: (a) a monoalkyltin compound RSn(T) 3 , and (b) a co-stabilizer, wherein the monoalkyltin compound represents at least 85 wt % of the tin based stabilizer composition, and wherein the co-stabilizer is chosen from the group consisting of: an organic polyol with at least three hydroxyl functions, an organic ester with a molecular weight of at least 172 g/mol, an ester of an organic polyol said ester having at least three free hydroxyl groups, and mixtures thereof. 
     
     
         18 . An article comprising a thermoplastic processable polymer composition according to  claim 1 , wherein the articles is selected from the group consisting of a hollow article, a packaging film, a blown film, a pipe, a foamed material, a heavy profile, a transparent-wall profile, a construction profile, a siding, a fitting, an office film, an apparatus enclosure, preferably a rigid or semi-rigid opaque or transparent PVC film, a PVC rigid foamed article, or a PVC pipe for drinking water or wastewater, a pressure pipe, a gas pipe, a cable-duct and a cable protection pipe, a pipe for industrial pipelines, a seepage pipe, a flow off pipe, and a guttering pipe or a drainage pipe.