Blends of thermoplastic copolyester elastomers with vinyl chloride polymers

Abstract

A uniform blend of about 5-95% by weight vinyl chloride polymer having a tensile modulus of at least about 50,000 p.s.i. and about 95-5% by weight of at least one thermoplastic segmented copolyester .[.polymer.]. containing (1) about 5-90 weight percent long chain ester units derived from at least one long chain glycol having a molecular weight of about 600-6000 and at least one low molecular weight dicarboxylic acid having a molecular weight less than about 300, and (2) about 10-95 weight percent short chain ester units derived from at least one low molecular weight diol having a molecular weight of less than about 250 and at least one low molecular weight dicarboxylic acid having a molecular weight of less than about 300. These blends exhibit excellent abrasion resistance which is maintained even in the presence of a large amount of plasticizer, improved low temperature flexibility, impact resistance and increased scuff resistance. These blends also exhibit improved processing because of excellent thermal stability and low melt viscosity.

We claim: 
     
       1. A uniform blend of about 5-95% by weight vinyl chloride polymer having a tensile modulus of at least about 50,000 p.s.i. and about 95-5% by weight of at least one .Iadd.elastomeric .Iaddend.thermoplastic segmented copolyester .[.polymer.]. containing (1) about 5-90 weight percent long chain ester units derived from at least one long chain glycol having a molecular weight of about 600--6000 and having a melting point of less than about 60°C. and a carbon-to-oxygen ratio of at least about 2 and at least one low molecular weight dicarboxylic acid having a molecular weight less than about 300 and (2) about 10-95 weight percent short chain ester units derived from at least one low molecular weight diol having a molecular weight of less than about 250 and at least one low molecular weight dicarboxylic acid having a molecular weight of less than about 300, said long chain ester units and short chain ester units randomly joined head-to-tail through ester linkages, said long chain ester units being represented by the formula ##EQU4##and said short chain ester units being represented by the formula ##EQU5##where G is a divalent radical remaining after the removal of terminal hydroxyl groups from said long chain glycol; R is a divalent radical remaining after removal of carboxyl groups from said dicarboxylic acid; and D is a divalent radical remaining after removal of hydroxyl from said low molecular weight diol .[...]..Iadd.; said copolyester having an inherent viscosity of at least 0.6..Iaddend. 
     
     
       2. The blend of claim 1 wherein the copolyester has a melting point of less than about 215°C. 
     
     
       3. The blend of claim 1 wherein the copolyester has 30-65 weight long chain ester units. 
     
     
       4. The blend of claim 1 wherein the long chain glycols are selected from the group consisting of poly(tetramethylene oxide)glycol, poly(1,2-propylene oxide)glycol, poly(ethylene oxide)glycol and poly(1,2-propylene oxide) glycol capped with ethylene oxide units. 
     
     
       5. The blends of claim 1 wherein the low molecular weight dicarboxylic acids are aromatic dicarboxylic acids containing 8-16 carbon atoms. 
     
     
       6. The blends of claim 1 wherein the low molecular weight diols are aliphatic diols containing 2-8 carbon atoms. 
     
     
       7. The blends of claim 1 wherein the vinyl chloride polymer is a vinyl chloride homopolymer or copolymer containing up to about 30% by weight of units from vinyl acetate or vinylidene chloride. 
     
     
       8. The blends of claim 1 containing 5-25% copolyester. 
     
     
       9. The blends of claim 1 containing about 10-50% copolyester. 
     
     
       10. The blends of claim 1 containing 30-60% copolyester. 
     
     
       11. The blends of claim 1 containing about 60-90% copolyester. 
     
     
       12. The blend of claim 1 wherein the copolyester is prepared by ester interchange of about 4.5 moles dimethyl terephthalate, 1.3 moles dimethyl isophthalate, 1 mole polytetramethylene glycol having a number average molecular weight of about 980, and excess 1,4-butanediol in the presence of a catalyst and a stabilizer, and polycondensation of the reaction product at about 250°C. 
     
     
       13. The blend of claim 1 wherein the copolyester is prepared by ester interchange of about 3.5 moles dimethyl terephthalate, 1 mole polytetramethyleneether glycol having a number average molecular weight of about 980, and excess 1,4 butanediol in the presence of a catalyst and a stabilizer.Iadd., .Iaddend.and polycondensation of the resulting reaction product at about 250°C. 
     
     
       14. The blend of claim 1 wherein the copolyester is prepared by ester interchange of about 7.9 moles dimethyl terephthalate, about 1 mole polytetramethyleneether glycol having a number average molecular weight of about 980, and excess 1,4-butanediol in the presence of a catalyst and a stabilizer.Iadd., .Iaddend.and polycondensation of the resulting reaction product at about 250°C. .Iadd.15. The blend of claim 1 wherein said copolyester has an inherent viscosity of 0.8-1.5. .Iaddend..Iadd.16. In a composition wherein a thermoplastic vinyl chloride polymer is uniformly blended with an elastomeric thermoplastic segmented copolyester, the improvement wherein said copolyester contains 1) 30 to 65% by weight of long-chain ester units derived from at least one long-chain glycol having a molecular weight of 600 to 6000 and at least one dicarboxylic acid having a molecular weight of less than 300, and   2) 70 to 35% by weight of short-chain ester units derived from at least one diol having a molecular weight of less than 250 and at least one dicarboxylic acid having a molecular weight of less than 300, and has an inherent viscosity of at least 0.6. .Iaddend..Iadd.17. The composition of claim 16 wherein the long-chain glycol is poly(tetramethylene oxide)glycol. .Iaddend..Iadd.18. The composition of claim 16 wherein the vinyl chloride polymer is polyvinyl chloride and the blend contains 30 to 60% by weight of copolyester. .Iaddend..Iadd.19. The composition of claim 16 wherein said copolyester has an inherent viscosity of 0.8-1.5. .Iaddend.