US 11,807,752 B2
Process for preparing graft rubber compositions with improved dewatering
Tobias Schulz, Cologne (DE); and Wolfgang Fischer, Heidelberg (DE)
Assigned to INEOS STYROLUTION GROUP GMBH, Frankfurt am Main (DE)
Appl. No. 17/262,284
Filed by INEOS STYROLUTION GROUP GMBH, Frankfurt am Main (DE)
PCT Filed Jul. 23, 2019, PCT No. PCT/EP2019/069764
§ 371(c)(1), (2) Date Jan. 22, 2021,
PCT Pub. No. WO2020/020869, PCT Pub. Date Jan. 30, 2020.
Claims priority of application No. 18185248 (EP), filed on Jul. 24, 2018.
Prior Publication US 2021/0269631 A1, Sep. 2, 2021
Int. Cl. C08L 51/00 (2006.01); C08F 220/18 (2006.01); C08F 2/22 (2006.01); C08F 6/00 (2006.01); C08F 6/22 (2006.01); C08F 212/08 (2006.01); C08F 220/44 (2006.01); C08K 3/30 (2006.01); C08L 25/12 (2006.01); C08L 55/02 (2006.01)
CPC C08L 51/003 (2013.01) [C08F 2/22 (2013.01); C08F 6/008 (2013.01); C08F 6/22 (2013.01); C08F 212/08 (2013.01); C08F 220/1804 (2020.02); C08F 220/44 (2013.01); C08K 3/30 (2013.01); C08L 25/12 (2013.01); C08L 55/02 (2013.01); C08K 2003/3063 (2013.01); C08L 2201/52 (2013.01); C08L 2205/03 (2013.01); C08L 2207/53 (2013.01)] 16 Claims
 
1. A process for the production of a graft copolymer composition comprising:
B: from 90 to 100% by weight of at least one graft copolymer B comprising:
B1: 50 to 90% by weight, based on the graft copolymer B, of at least one graft base B1, obtained by emulsion polymerization of:
B11: 50 to 100% by weight, based on the graft base B1, of at least one monomer B11 selected from C1-C8 alkyl(meth)acrylate and butadiene;
B12: 0 to 10% by weight, based on the graft base B1, of at least on poly-functional cross-linking monomer B12; and
B13 0 to 50% by weight, based on the graft base B1, of at least one further monomer B13 selected from styrene, α-methylstyrene, C1-C4-alkylstyrene, acrylonitrile, methacrylonitrile, isoprene, butadiene, chloroprene, methyl(meth)acrylate, alkylenglycol-di(meth)acrylate, and vinylmethylether;
where the sum of B11, B12, and B13 equals 100% by weight; and
B2: 10 to 50% by weight, based on the graft copolymer B, of at least one graft shell B2, which is obtained via emulsion polymerization in the presence of the at least one graft base B1 of:
B21: 50 to 100% by weight, based on graft shell B2, of at least one monomer B21 selected from styrene, α-methylstyrene or mixtures of styrene and at least one further monomer selected from α-methylstyrene, p-methylstyrene, and C1-C8 alkyl(meth)acrylate; and
B22: 0 to 50% by weight, based on graft shell B2, of at least one monomer B22 selected from acrylonitrile or mixtures of acrylonitrile and at least one further monomer chosen from methacrylonitrile, acrylamide, vinylmethyl ether, anhydrides of unsaturated carboxylic acids, and imides of unsaturated carboxylic acids;
where the total sum of graft base B1 and graft shell B2 equals 100% by weight; and
K1: from 0 to 10% by weight of at least one other component K1;
comprising the following steps:
a) preparation of the at least one graft copolymer B encompassing emulsion polymerization of the monomers B21 and B22 in the presence of at least one graft base B1 to form the at least one graft shell B2, wherein the graft copolymer B is obtained in the form of a latex;
b) precipitation of the at least one graft copolymer B after its emulsion polymerization in step a), wherein the graft copolymer B latex is mixed with at least one precipitation solution PS resulting in a precipitation mixture, wherein the at least one precipitation solution PS comprises at least one alkaline-earth metal salt, and wherein the precipitation mixture has a solid content of more than 10.2% by weight;
c) mechanical dewatering of the precipitated graft copolymer B, where a graft copolymer B having a water content equal or less than 40% by weight is obtained, and wherein the molar ratio of alkaline metal ions to alkaline-earth metal ions in the graft copolymer B is equal or less than 0.16;
d) optionally washing of the dewatered graft copolymer B;
e) optionally drying of the dewatered graft copolymer B obtained in step c) or d); and
f) optionally addition of one or more optional components K1.