Polyorganosiloxane latex, graft copolymer using the same, thermoplastic resin composition, and molded body

Abstract

A variety of molded bodies having high weatherability, impact resistance, designability, and the like, and a polyorganosiloxane latex and a graft copolymer used as the raw material therefor are provided. A polyorganosiloxane latex having a mass average particle diameter (Dw) of a polyorganosiloxane particle of 100 to 200 nm, and a ratio of the mass average particle diameter (Dw) to a number average particle diameter (Dn) (Dw/Dn) of 1.0 to 1.7. A polyorganosiloxane-containing vinyl-based copolymer (g) obtained by polymerizing one or more vinyl-based monomers in the presence of the latex. A graft copolymer (G) obtained by graft polymerizing one or more vinyl-based monomers in the presence of the copolymer. A thermoplastic resin composition including the graft copolymer (Ga) and a thermoplastic resin (Ha) except for the graft copolymer (Ga). A molded body obtained by molding the resin composition. A lamp housing for vehicle lighting including the molded body obtained by molding the composition.

1 . A polyorganosiloxane latex, wherein a mass average particle diameter (Dw) of a polyorganosiloxane particle is 100 to 200 nm, and wherein a ratio (Dw/Dn) of the mass average particle diameter (Dw) to a number average particle diameter (Dn) of the particle is 1.0 to 1.7. 
     
     
         2 . The polyorganosiloxane latex according to  claim 1 , wherein a standard deviation of the mass average particle diameter (Dw) of the polyorganosiloxane particle is 0 to 80. 
     
     
         3 . The polyorganosiloxane latex according to  claim 1 , wherein a proportion of the polyorganosiloxane particle having a particle diameter less than 50 nm is 5% by mass or less based on the total amount of the particle, and wherein a proportion of the polyorganosiloxane particle having a particle diameter of 300 nm or more is 20% by mass or less based on the total amount of the particle. 
     
     
         4 . A polyorganosiloxane-containing vinyl-based copolymer obtained by polymerizing one or more vinyl-based monomers in the presence of the polyorganosiloxane latex according to  claim 1 . 
     
     
         5 . The polyorganosiloxane-containing vinyl-based copolymer according to  claim 4 , wherein a mass average particle diameter (Dw) of a particle in the polyorganosiloxane-containing vinyl-based copolymer is 110 nm to 800 nm, and a ratio (Dw/Dn) of the mass average particle diameter (Dw) to a number average particle diameter (Dn) of the particle is 1.0 to 2.0. 
     
     
         6 . The polyorganosiloxane-containing vinyl-based copolymer according to  claim 4 , wherein the vinyl-based monomer is an acrylic acid ester. 
     
     
         7 . A graft copolymer (G) obtained by graft polymerizing one or more vinyl-based monomers in the presence of the polyorganosiloxane-containing vinyl-based copolymer according to  claim 4 . 
     
     
         8 . The graft copolymer (G) according to  claim 7 , wherein a molded body obtained by molding the following composition exhibits the following performance (1) and (2) when evaluated under the following measurement conditions:
 (1) a Charpy impact strength at 23° C. is 6 kJ/m 2  or more, and   (2) a diffuse reflectance is 5% or less;   
       test piece production conditions of:
 (a) 33 parts by mass of a graft copolymer (Ga), 
 (b) 9 parts by mass of an acrylonitrile-styrene copolymer comprising 25% by mass of an acrylonitrile unit and 75% by mass of a styrene unit and having a reduced viscosity (ηsp/c) of 0.40 dL/g in an N,N-dimethylformamide solution of 0.2 g/dL at 25° C., 
 (c) 9 parts by mass of an acrylonitrile-styrene copolymer comprising 28% by mass of an acrylonitrile unit and 72% by mass of a styrene unit and having a reduced viscosity of 0.62 dL/g in an N,N-dimethylformamide solution of 0.2 g/dL at 25° C., 
 (d) 50 parts by mass of an acrylonitrile-styrene-N-phenylmaleimide copolymer comprising 22% by mass of an acrylonitrile unit, 55% by mass of a styrene unit, and 23% by mass of an N-phenylmaleimide unit and having a reduced viscosity of 0.40 dL/g in an N,N-dimethylformamide solution of 0.2 g/dL at 25° C., 
 (e) 0.5 parts by mass of ethylenebisstearylamide, 
 (f) 0.03 parts by mass of silicone oil, and 
 (g) 0.05 parts by mass of carbon black; 
 wherein the seven materials (a) to (g) above are blended and kneaded using a volatilizing extruder whose barrel is heated to a temperature of 260° C. to obtain pellets; the pellets are molded using a 4-ounce injection molding machine in conditions of a cylinder temperature of 260° C. and a mold temperature of 60° C. to obtain a test piece 1 with a length of 80 mm, a width of 10 mm and a thickness of 4 mm; 
 
       and a plate-like molded body 2 a length of 100 mm, a width of 100 mm and a thickness of 2 mm is obtained in the same manner as above in conditions of a cylinder temperature of 260° C., a mold temperature of 60° C., and an injection rate of 5 g/sec; 
       Charpy impact strength measurement conditions of:
 measurement is conducted on a V-notched test piece 1 that is left under a 23° C. atmosphere for 12 hours or more by a method according to ISO 179; 
 
       diffuse reflectance measurement conditions of:
 a 50 nm aluminum film is formed through a direct deposition on the surface of the molded body 2 by a vacuum deposition method in conditions of a degree of vacuum of 6.0×10 −3  Pa and a film forming rate of 10 angstroms/sec; and a diffuse reflectance (%) of the obtained molded body is measured using a reflectance meter. 
 
     
     
         9 . The graft copolymer (Ga) according to  claim 8 , comprising 5 to 25% by mass of polyorganosiloxane based on 100% by mass of a polyorganosiloxane-containing vinyl-based copolymer, wherein a mixture of a vinyl cyanide-based monomer and an aromatic vinyl-based monomer is graft polymerized with the polyorganosiloxane-containing vinyl-based copolymer, wherein the polyorganosiloxane-containing vinyl-based copolymer has a mass average particle diameter (Dw) of 120 to 200 nm, wherein a proportion of a particle having a particle diameter of 100 nm or less is 15% by mass or less based on the total amount of the particle, and wherein a proportion of the particle having a particle diameter of 400 nm or more is 1% by mass or less based on the total amount of the particle. 
     
     
         10 . The graft copolymer (Ga) according to  claim 9 , wherein the polyorganosiloxane contains 0.5 to 5 parts by mass of a component derived from a siloxane-based crosslinking agent based on 100 parts by mass of the organosiloxane. 
     
     
         11 . A thermoplastic resin composition (Ia) comprising the graft copolymer (Ga) according to  claim 8 , and a thermoplastic resin (Ha) except for the graft copolymer (Ga). 
     
     
         12 . The thermoplastic resin composition (Ia) according to  claim 11 , wherein the thermoplastic resin (Ha) is a copolymer comprising 0 to 40% by mass of a vinyl cyanide-based monomer unit, 40 to 80% by mass of an aromatic vinyl-based monomer unit, and 0 to 60% by mass of another monomer unit whose monomer is copolymerizable with these monomers. 
     
     
         13 . A molded body obtained by molding the thermoplastic resin composition (Ia) according to  claim 11 . 
     
     
         14 . A lamp housing for vehicle lighting comprising a molded body obtained by molding the thermoplastic resin composition (Ia) according to  claim 11 . 
     
     
         15 . The graft copolymer (G) according to  claim 7 , wherein a molded body obtained by molding the following composition exhibits the following performance (1) and (2) when evaluated under the following measurement conditions:
 (1) L* is 24 or less, and   (2) a Charpy impact strength at −30° C. is 6 kJ/m 2  or more;   
       test piece production conditions of:
 (a) 42 parts by mass of a graft copolymer (Gb), 
 (b) 58 parts by mass of an acrylonitrile-styrene copolymer comprising 34% by mass of an acrylonitrile unit and 66% by mass of a styrene unit and having a reduced viscosity (ηsp/c) of 0.62 dL/g in an N,N-dimethylformamide solution of 0.2 g/dL at 25° C., 
 (c) 0.3 parts by mass of ethylenebisstearylamide, and 
 (d) 0.5 parts by mass of carbon black; 
 wherein the four materials (a) to (d) above are blended and kneaded using a volatilizing extruder whose barrel is heated to a temperature of 230° C. to obtain pellets; the pellets are molded using a 4-ounce injection molding machine in conditions of a cylinder temperature of 230° C. and a mold temperature of 60° C. to obtain a test piece 3 with a length of 80 mm, a width of 10 mm and a thickness of 4 mm and a tensile test piece 4 a length of 170 mm, a width of 20 mm and a thickness of 4 mm; 
 
       Charpy impact strength measurement conditions of:
 measurement is conducted on a V-notched test piece 3 that is left under a −30° C. atmosphere for 12 hours or more by a method according to ISO 179; 
 
       L*measurement conditions of:
 L* is measured for the tensile test piece 4 using a spectrophotometer on a side opposite to a gate. 
 
     
     
         16 . The graft copolymer (Gb) according to  claim 15 , comprising 15 to 80% by mass of polyorganosiloxane based on 100% by mass of a polyorganosiloxane-containing vinyl-based copolymer, wherein a mixture of a vinyl cyanide-based monomer and an aromatic vinyl-based monomer is graft polymerized with the polyorganosiloxane-containing vinyl-based copolymer, wherein the polyorganosiloxane-containing vinyl-based copolymer has a mass average particle diameter (Dw) of 110 to 250 nm, wherein a proportion of a particle having a particle diameter less than 100 nm is 20% by mass or less based on the total amount of the particle, and wherein a proportion of the particle diameter of 300 nm or more is 20% by mass or less based on the total amount of the particle. 
     
     
         17 . The graft copolymer (Gb) according to  claim 16 , wherein the polyorganosiloxane contains 0.5 to 3 parts by mass of a component derived from a siloxane-based crosslinking agent based on 100 parts by mass of the organosiloxane. 
     
     
         18 . A thermoplastic resin composition (Ib) comprising the graft copolymer (Gb) according to  claim 15  and a thermoplastic resin (Hb) except for the graft copolymer (Gb). 
     
     
         19 . The thermoplastic resin composition (Ib) according to  claim 18 , wherein the thermoplastic resin (Hb) is a copolymer comprising 0 to 40% by mass of a vinyl cyanide-based monomer unit, 40 to 80% by mass of an aromatic vinyl-based monomer unit, and 0 to 60% by mass of another vinyl-based monomer unit whose monomer is copolymerizable with these monomers. 
     
     
         20 . A molded body obtained by molding the thermoplastic resin composition (Ib) according to  claim 18 . 
     
     
         21 . A method of producing a polyorganosiloxane latex, the method comprising a step of dropping an emulsion (B) comprising organosiloxane, an emulsifier, and water into a water-based medium (A) comprising water, an organic acid catalyst, and an inorganic acid catalyst; and
 a step of performing polymerization, wherein a total amount of the organic acid catalyst and the emulsifier is 0.5 to 6 parts by mass based on 100 parts by mass of the organosiloxane, wherein the pH of the water-based medium (A) measured at 25° C. is within the range of 0 to 1.2, and wherein the dropping rate of the emulsion (B) is a rate such that an amount of organosiloxane to be fed is 0.5 [parts by mass/min] or less when a total amount of organosiloxane to be used is 100 parts by mass.