A thermoplastic molding composition comprising (A) 15 to 45 wt.-% graft copolymer (A) obtained by emulsion polymerization of styrene and acrylonitrile in presence of an agglomerated butadiene rubber latex (A1) with D50 of 150 to 800 nm; (B) 40 to 75 wt.-% copolymer (B) of styrene and acrylonitrile having a weight ratio of 80:20 to 65:35 and Mw of 150,000 to 300,000 g/mol, (C) 2.0 to 5.0 wt.-% elastomeric block copolymer (C) made from 15 to 65 wt.-% diene, and 35 to 85% by weight vinylaromatic monomer; (D) 2.0 to 5.0 wt.-% titanium dioxide pigment D comprising at least 95 wt.-% titanium dioxide and 1.7 to 3.3 wt.-% alumina; and (E) 0 to 7.0 wt.-% of at least one additive/processing aid (E) different from (D); having a high chemical resistance, high color and thermal stability and low tendency to delamination. This can be used for sheet extrusion and thermoforming, in particular as inner liner for a cooling apparatus.

A method of preparing a graft copolymer includes a step of performing coagulation by adding an acid coagulant to 100 parts by weight (based on solids) of graft copolymer latex prepared by graft-polymerizing an aromatic vinyl compound and a vinyl cyanide compound onto conjugated diene rubber latex; and a step of performing coagulation once more by adding a salt coagulant thereto. In a resulting graft copolymer, coagulation efficiency may be improved and the gloss of the prepared graft copolymer may be increased. In addition, since a b-value measured using a Hunter lab colorimeter and a b-value measured after being left at 250° C. for 15 minutes are low, the graft copolymer may have excellent color characteristics. In addition, since heating loss is low and scorch time is long, the graft copolymer may have excellent processing characteristics.

A method of preparing a graft copolymer includes a step of performing coagulation by adding an acid coagulant to 100 parts by weight (based on solids) of graft copolymer latex prepared by graft-polymerizing an aromatic vinyl compound and a vinyl cyanide compound onto conjugated diene rubber latex; and a step of performing coagulation once more by adding a salt coagulant thereto. In a resulting graft copolymer, coagulation efficiency may be improved and the gloss of the prepared graft copolymer may be increased. In addition, since a b-value measured using a Hunter lab colorimeter and a b-value measured after being left at 250° C. for 15 minutes are low, the graft copolymer may have excellent color characteristics. In addition, since heating loss is low and scorch time is long, the graft copolymer may have excellent processing characteristics.

An acrylic rubber, including: 50 to 99.9% by weight of a bond unit derived from at least one (meth) acrylic acid ester selected from the group consisting of (meth) acrylic acid alkyl ester and (meth) acrylic acid alkoxyalkyl ester; 0.1 to 20% by weight of a bond unit derived from a monomer containing a reactive group; and 0 to 30% by weight of a bond unit derived from other monomer, wherein the acrylic rubber contains a phenolic anti-aging agent represented by a general formula (1),

##STR00001##

(R1 represents an isopropyl group or a t-butyl group, and R2 represents an alkyl group having 1 to 12 carbon atoms), and the weight average molecular weight (Mw) of the acrylic rubber is in the range of 100,000 to 5,000,000.

An acrylic rubber, including: 50 to 99.9% by weight of a bond unit derived from at least one (meth) acrylic acid ester selected from the group consisting of (meth) acrylic acid alkyl ester and (meth) acrylic acid alkoxyalkyl ester; 0.1 to 20% by weight of a bond unit derived from a monomer containing a reactive group; and 0 to 30% by weight of a bond unit derived from other monomer, wherein the acrylic rubber contains a phenolic anti-aging agent represented by a general formula (1),

##STR00001##

(R1 represents an isopropyl group or a t-butyl group, and R2 represents an alkyl group having 1 to 12 carbon atoms), and the weight average molecular weight (Mw) of the acrylic rubber is in the range of 100,000 to 5,000,000.

An acrylic rubber, including: 50 to 99.9% by weight of a bond unit derived from at least one (meth) acrylic acid ester selected from the group consisting of (meth) acrylic acid alkyl ester and (meth) acrylic acid alkoxyalkyl ester; 0.1 to 20% by weight of a bond unit derived from a monomer containing a reactive group; and 0 to 30% by weight of a bond unit derived from other monomer, wherein the acrylic rubber contains a phenolic anti-aging agent represented by a general formula (1),

##STR00001##

(R1 represents an isopropyl group or a t-butyl group, and R2 represents an alkyl group having 1 to 12 carbon atoms), and the weight average molecular weight (Mw) of the acrylic rubber is in the range of 100,000 to 5,000,000.

A method for producing a fluoropolymer powder including (A1) adding, to a fluoropolymer aqueous dispersion obtained by polymerization using a carboxylic acid type hydrocarbon surfactant, and an acid to adjust a pH to 4.0 or less and cause coagulation to thereby obtain a wet fluoropolymer powder containing a fluorine-containing compound represented by the following general formula (1A), and (B1) heat-treating the wet fluoropolymer powder at a temperature higher than 150° C. and lower than 240° C.: General Formula (1A): H—(CF.sub.2).sub.m—COOH wherein m is 3 to 19.

A method for producing a fluoropolymer powder including (A1) adding, to a fluoropolymer aqueous dispersion obtained by polymerization using a carboxylic acid type hydrocarbon surfactant, and an acid to adjust a pH to 4.0 or less and cause coagulation to thereby obtain a wet fluoropolymer powder containing a fluorine-containing compound represented by the following general formula (1A), and (B1) heat-treating the wet fluoropolymer powder at a temperature higher than 150° C. and lower than 240° C.: General Formula (1A): H—(CF.sub.2).sub.m—COOH wherein m is 3 to 19.

The present invention relates to a multistage polymer, its composition, its process of preparation, and its use as impact modifier in thermoplastic compositions. More particularly the present invention relates a process for manufacturing a multistage polymer, a multistage polymer in thermoplastic compositions, which provides the composition having satisfying thermal stability.

The present invention relates to a multistage polymer, its composition, its process of preparation, and its use as impact modifier in thermoplastic compositions. More particularly the present invention relates a process for manufacturing a multistage polymer, a multistage polymer in thermoplastic compositions, which provides the composition having satisfying thermal stability.