Patent GB-1049772-A (GB)
Title: Coated particles
Inventor: COX GEORGE HAROLD
IPC: C09B67/08
Filed: 1961-10-04
Abstract: Particles of organic and inorganic pigments are coated with polymeric material by dispersing them in a solution of a block or graft polymer comprising polymeric components of different degrees of polarity, and modifying the polarity of the solution so that at least one, but not all, of the components of the polymer become non-solvated by the liquid of the solution. The modification of the polarity of the solution of block or graft polymer may be achieved by adding thereto a miscible liquid of different polarity.  The coated pigments may be used in the preparation of paints The Examples describe (3) coating particles of yellow oxide pigment with a block polymer of polyisobutylene and methyl and dimethylaminoethyl methacrylates dissolved in white spirit and adding the resulting dispersion to a linseed oil-pentaerythritol alkyd vehicle to form a paint, (5) coating particles of cyan blue pigment with a block polymer methyl methacrylate and methacrylic acid on a copolymer of lauryl methacrylate and allyl alcohol esterified with acrylate groups, (6) coating mixed particles of titanium dioxide and cyan blue pigments with a graft copolymer of methyl methacrylate and acrylic acid on polybutadiene in solution in xylol and adding the resulting dispersion to a linseed oil-pentaerythritol alkyd vehicle to form a paint, and (8) coating aluminium flake pigment with a graft copolymer of methyl methacrylate and methacrylic acid on a copolymer of lauryl, octyl and glycidyl methacrylates esterified with acrylic acid.ALSO:Particles of inorganic pigments are coated with polymer by dispersing them in a solution of a block or graft polymer comprising polymeric components of different degrees of polarity, and modifying the polarity of the solution so that at least one, but not all, of the components of the polymer become non-solvated by the liquid of the solution.  The modification of the polarity of the solution of block or graft polymer may be achieved by adding thereto a miscible liquid of different polarity.  The Examples describe the use of the process to coat particles of (1) vegetable black with a graft copolymer of methyl methacrylate and methacrylic acid on degraded rubber, (2) titanium dioxide with a graft copolymer of methyl methacrylate and acrylic acid on polybutadiene, (3) yellow oxide pigment with a block copolymer of methyl methacrylate and dimethylaminoethyl methacrylate on polyisobutylene, (4) titanium dioxide with a graft copolymer of acrylamide, methacrylic acid, ethyl acrylate and methyl methacrylate on a copolymer of ethylene glycol monomethacrylate and styrene containing pendant methacrylate ester groups, (6) mixed titanium dioxide and cyan blue pigments with the graft copolymer of (2), (10) titanium dioxide with a graft copolymer of methyl methacrylate and methacrylic acid on a copolymer of lauryl, octyl and glycidyl methacrylates esterified with acrylic acid, (11) titanium dioxide with a graft copolymer of methyl methacrylate and methacrylic acid on degraded rubber, and (12) titanium dioxide with a copolymer of methyl methacrylate, methacrylic acid and the methacrylic ester of methoxy-polyethylene glycol 750.  The suspended coated particles may be converted to the dry state and may then be redispersed in liquids which resolvate the second component of the polymer.ALSO:Solid particles are coated with polymeric material by dispersing them in a solution of a block or graft polymer comprising polymeric components of different degrees of polarity, and modifying the polarity of the solution so that at least one, but not all, of the components of the polymer become non-solvated by the liquid of the solution.  Solid particles which may be coated by the process are pigments, metallic powders and particles of polymers such as polyvinyl chloride, polyvinyl acetate, polyvinylidene chloride, polyethylene and polyacrylonitrile.  The modification of the polarity of the solution of block or graft polymer may be achieved by adding thereto a miscible liquid of different polarity.  The examples describe the use of the process to coat particles of (1) vegetable black with a graft copolymer of methyl methacrylate and methacrylic acid on degraded rubber, (2) titanium dioxide with a graft copolymer of methyl methacrylate and acrylic acid on polybutadiene, (3) yellow oxide pigment with a block copolymer of methyl methacrylate and dimethylaminoethyl methacrylate with polyisobutylene, (4) rutile titanium dioxide with a graft copolymer of acrylamide, methacrylic acid, ethyl acrylate and methyl methacrylate on a copolymer of ethylene glycol monomethacrylate and styrene containing pendant methacrylate ester groups, (5) cyan blue pigment with a block copolymer of methyl methacrylate and methacrylic acid on a copolymer of lauryl methacrylate and allyl alcohol esterified with acrylate groups, (6) rutile titanium dioxide and cyan blue with the graft copolymer of (2), (7) polyvinyl chloride with a graft copolymer of methyl methacrylate and methacrylic acid on a copolymer of lauryl, octyl and glycidyl methacrylates esterified with acrylic acid, (8) aluminium flake with the graft copolymer of (7), (10) titanium dioxide with the graft copolymer of (7), (11) titanium dioxide with a graft copolymer of methyl methacrylate and methacrylic acid on degraded rubber, and (12) titanium dioxide with a copolymer of methyl methacrylate, methacrylic acid and the methacrylic ester of methoxy-polyethylene glycol 750.  The examples describe also coating compositions containing the pigment dispersions of: (2) and acetyl tributyl citrate and a dispersion of a 98/2 methyl methacrylate/methacrylic acid copolymer in petroleum ether, (3) and a linseed oil-pentaerythritol alkyd vehicle in nonanol and white spirit, (4) and either a coconut oil-modified short oil glycerol/phthalic acid resin and a butylated melamine resin in mineral spirit, methyl ethyl ketone, MeOH, acetone, xylol and butanol or a solution of a styrene/ethyl acrylate/acrylic acid copolymer, an epoxide resin and a quaternary ammonium base, (5) and isobutyl sextol phthalate and a dispersion of a methylmethacrylate/methacrylic acid copolymer in petroleum ether, (6) and a linseed oil-pentaerythritol alkyd in octanol and mineral spirit, (8) and a dispersion of polymethyl methacrylate and isobutyl cyclohexanyl phthalate, (9) and either an alkyd vehicle as in (6) with kerosene and petroleum as additional solvents or a non-aqueous methyl methacrylate copolymer dispersion, and (12) and a water-based emulsion paint.  The particles of (7) are dispersed in hydrocarbon liquid with sextol phthalate plasticizers and, optionally, titanium dioxide, and films are prepared from the compositions. The preparation of graft and block polymers is described, either by polymerizing monomers and polymers in solution in an inert solvent in the present of a peroxide or azo catalyst, or by masticating monomer with polymer.ALSO:Solid particles are coated with polymeric material by dispersing them in a solution of a block or graft polymer comprising polymeric components of different degrees of polarity, and modifying the polarity of the solution so that at least one, but not all, of the components of the polymer become non-solved by the liquid of the solution.  Solid particles which may be coated by the process are organic pigments, metallic powders and particulate polymers, e.g. polyvinyl and polyvinylidene chlorides, polyethylene and polyacrylonitrite.  The modification of the polarity of the solution of block or graft polymer may be achieved by adding thereto a miscible liquid of different polarity.  The examples describe the use of the process to coat particles of: (5) cyan blue pigment with a block copolymer of methyl methacrylate and methacrylic acid on a copolymer of lauryl methacrylate and allyl alcohol esterified with acrylate groups, (6) mixed titanium and cyan blue pigments with a graft copolymer of methyl methacrylate and acrylic acid on polybutadiene, (7) polyvinyl chloride with a graft copolymer of methyl methacrylate and methacrylic acid on a copolymer of lauryl, octyl and glycidyl methacrylates esterified with acrylic acid, and (8) aluminium flake with the graft copolymer of (7), the resulting coated aluminium dispersion being added to a dispersion of polymethyl methacrylate to provide a composition which is sprayed on an undercoated metal panel and stored at 127 degrees to yield a coating of metallic appearance.