HALOGEN-CONTAINING THERMOPLASTIC RESINS COMPOSITIONS
A halogen-containing thermoplastic resin composition comprises (i) a halogen-containing thermoplastic resin; and (ii) a graft copolymer comprising (a) a first polymer produced by emulsion polymerization of at least one vinyl ester of a C 1 to C 20 carboxylic acid in the presence of a nonionic surfactant and (b) a second polymer having a glass transition temperature of at least 45° C. produced by emulsion polymerization of at least one monomer in the presence of the first polymer.
1 . A halogen-containing thermoplastic resin composition comprising:
(i) a halogen-containing thermoplastic resin; and
(ii) a graft copolymer comprising
(a) a first polymer produced by emulsion polymerization of at least one vinyl ester of a C 1 to C 20 carboxylic acid in the presence of a nonionic surfactant; and
(b) a second polymer having a glass transition temperature of at least 45° C. produced by emulsion polymerization of at least one monomer in the presence of the first polymer.
2 . The composition of claim 1 , wherein the halogen-containing thermoplastic resin comprises polyvinyl chloride.
3 . The composition of claim 1 and comprising from 0.5 weight % to 80 weight % of the graft copolymer (ii).
4 . The composition claim 1 , wherein the vinyl ester of a C 1 to C 20 carboxylic acid comprises vinyl acetate.
5 . The composition of claim 1 , wherein the first polymer also comprises ethylene, preferably in an amount from 5 to 60 wt % of the first polymer.
6 . The composition of claim 1 , wherein the graft copolymer has a weight average particle size of less than 200 nm.
7 . The composition of claim 1 , wherein at least the first polymer (a) comprises up to 5 wt % of a cross-linking monomer.
8 . The composition of claim 1 , wherein the at least one monomer of the second polymer (b), when polymerized alone, gives a homopolymer with a glass transition temperature of 65 to 150° C.
9 . The composition of claim 1 , wherein the at least one monomer of the second polymer (b) comprises an ester of methacrylic acid and a C 1 to C 10 alcohol.
10 . The composition of claim 1 , wherein the second polymer (b) comprises at least 60 wt % of an ester of methacrylic acid and a C 1 to C 10 alcohol.
11 . The composition of claim 1 , wherein the at least one monomer of the second polymer (b) comprises methyl methacrylate, ethyl methacrylate, butyl methacrylate, isopropyl methacrylate, phenyl methacrylate and mixtures thereof, preferably methyl methacrylate.
12 . The composition of claim 1 , wherein the weight ratio of the first polymer (a) to the second polymer (b) is from 5:95 to 95:5, preferably from 80:20 to 50:50.
13 . The composition of claim 1 and comprising from 0.5% to 10% of the graft copolymer based on the total weight of the halogen-containing thermoplastic resin and the graft copolymer.
14 . The composition of claim 1 and comprising from 20% to 60% of the graft copolymer based on the total weight of the halogen-containing thermoplastic resin and the graft copolymer.