| 摘要 |
Pigment compositions are prepared by mixing an aqueous mass of pigment of particle size 0.02-1.0 micron with an aqueous dispersion of a copolymer, prepared by emulsion polymerization 30-70 parts of styrene and 70-30 parts of a C1- 12 (preferably ethyl) acrylate or methacrylate, of particle size 0.02-1.0 micron, subsequently coagulating the mixture at a temperature ranging from ambient to the boil, removing the aqueous phase from the coagulum and drying and pulverizing the solid. The aqueous mass of pigment may be prepared by dispersing the pigment with a wetting agent, e.g. the sodium or potassium salt of dinaphthyl methane disulphonate, octyl or butyl naphthalene sulphonate or a sulphated alkyl phenol/ polyoxyethylene condensate. Coagulation may be achieved by addition of hydrochloric acid or a salt and may be in the presence of an agent for improving the pigment texture, e.g. rosin or a cresol/formaldehyde resin. The copolymer, which may be a terpolymer, e.g. styrene/n-butyl acrylate/2-ethylhexyl acrylate, may be produced using sodium N-lauryl sarcosinate as emulsifier. The pigment composition may be blended with polyvinyl chloride, polystyrene or an acrylonitrile/butadiene/styrene terpolymer. Examples describe the emulsion polymerization of styrene and ethyl acrylate using n-dodecyl mercaptan as chain transfer agent and potassium persulphate as catalyst. Numerous pigments consisting of organic colouring matter are exemplified under trade names. The composition may be used to form an ink, by blending (1) with a vinyl chloride/vinyl acetate/ maleic anhydride terpolymer and methyl ethyl ketone, (2) with a zinc/calcium resionate and toluene, (3) with a chlorinated rubber and toluene. |
