Method for preparing latex containing pigment copolymerized with a crystalline polymer

Abstract

A method of preparing a latex that includes pigments copolymerized with a crystalline polymer includes: dispersing a pigment and a dispersing agent in water having an ultra-high purity to obtain a pigment dispersion; dissolving a crystalline monomer in a basic monomer mixture to obtain an organic phase; dissolving while heating the dispersing agent in water having an ultra-high purity, and then mixing the solution with the pigment dispersion to obtain an aqueous phase; mixing and agitating the organic phase and the aqueous phase to obtain a homogenized solution; agitating and heating the homogenized solution; adding a polymerization initiator to the homogenized solution to be reacted; and cooling the reaction solution to room temperature.

1 . A method of preparing a latex, comprising: 
 copolymerizing pigments with a crystalline polymer in one process in a reaction solution without a separate aggregation process to facilitate control of amounts and aggregation of each component in the latex and provide the latex with a minimized particle size distribution, wherein the crystalline polymer material acts as a mold release agent and has a lower melting point than a melting point of the latex, when prepared; and    cooling the reaction solution.    
   
   
       2 . The method of preparing a latex of  claim 1 , wherein a pigment and a dispersing agent are dispersed in water having an ultra-high purity to obtain a pigment dispersion and the dispersing agent used in the dispersing the pigment and the dispersing agent in water is an anionic surfactant selected from the group consisting of a carboxylate, an ester sulfate and a sulfonate; or a non-ionic surfactant selected from the group consisting of a polyoxyethylene alkylether, a polyoxyethylene alkylphenylether, a polyoxyethylene fatty acid ester, a sorbitan fatty acid ester, a polyoxysorbitan fatty acid ester, a polyoxyethylene alkylamine and an oxyethyleneoxypropylene block copolymer.  
   
   
       3 . The method of preparing a latex of  claim 2 , wherein the pigment dispersion in the dispersing the pigment and the dispersing agent in water is prepared by agitating at a speed of 2,000 to 10,000 rpm for 1 to 5 hours.  
   
   
       4 . The method of preparing a latex of  claim 3 , wherein a crystalline monomer is dissolved in a basic monomer mixture to obtain an organic phase and the basic monomer mixture is a mixture of an aromatic-based vinyl monomer selected from the group consisting of a styrene, an o-methyl styrene, an m-methyl styrene, a p-methyl styrene, a p-methoxy styrene, a p-phenyl styrene, a p-chloro styrene, a p-ethyl styrene, a p-n-butyl styrene, a p-tert-butyl styrene, a p-n-hexyl styrene, a p-n-octyl styrene, a p-n-nonyl styrene, a p-n-decyl styrene, a p-n-dodecyl styrene, a 2,4-dimethyl styrene, a 3,4-dichloro styrene and their derivatives; a (meth)acrylic acid ester-based monomer selected from the group consisting of an acrylic acid methyl, an acrylic acid ethyl, an acrylic acid butyl, an acrylic acid-2-ethyl hexyl, an acrylic acid cyclohexyl, an acrylic acid phenyl, a methacrylic acid methyl, a methacrylic acid ethyl, a methacrylic acid butyl, a methacrylic acid hexyl, a methacrylic acid-2-ethyl hexyl, β-hydroxy acrylic acid ethyl, γ-amino acrylic acid propyl, a methacrylic acid stearyl, a methacrylic acid dimethyl amino ethyl, a methacrylic acid diethyl amino ethyl and their derivatives; a vinyl ester-based monomer selected from the group consisting of an acetic acid vinyl, a propionic acid vinyl, a benzoic acid vinyl and their derivatives; a vinyl ether-based monomer selected from the group consisting of a vinyl methyl ether, a vinyl ethyl ether, a vinyl isobutyl ether, a vinyl phenyl ether and their derivatives; a monoolefine-based monomer selected from the group consisting of an ethylene, a propylene, an isobutylene, a 1-butene, a 1-pentene, a 4-methyl-1-pentene and their derivatives; a diolefine-based monomer selected from the group consisting of a butadiene, an isoprene, a chloroprene and their derivatives; and a halogenated olefine-based monomer selected from the group consisting of a vinyl chloride, a vinylidene, chloride, a vinyl fluoride and their derivatives.  
   
   
       5 . The method of preparing a latex of  claim 4 , wherein the crystalline monomer has 18 to 32 carbon atoms, and a melting point of 30° C. to 70° C.  
   
   
       6 . The method of preparing a latex of  claim 4 , wherein the crystalline monomer forms a crystalline polymer by copolymerization with the basic monomer, and the amount of the crystalline polymer in the latex is 1 to 50 parts by weight based on 100 parts by weight of the latex.  
   
   
       7 . The method of preparing a latex of  claim 4 , wherein the basic monomer forms a polymer material having a glass transition temperature of 40° C. to 100° C. by polymerization, and the crystalline monomer forms a crystalline polymer material having a melting point of 30° C. to 80° C. by copolymerization with the basic monomer.  
   
   
       8 . The method of preparing a latex of  claim 4 , wherein a dispersing agent is dissolved, while heating, in water having an ultra-high purity to form a solution, and then the solution is mixed with the pigment dispersion to form an aqueous phase, wherein the dispersing agent is a non-ionic surfactant selected from the group consisting of a polyoxyethylene alkyl ether, a polyoxyethylene alkyl phenyl ether, a polyoxyethylene fatty acid ester, a sorbitan fatty acid ester, a polyoxy sorbitan fatty acid ester, a polyoxyethylene alkyl amine and an oxyethyleneoxypropylene block copolymer.  
   
   
       9 . The method of preparing a latex of  claim 8 , wherein the organic phase and the aqueous phase are mixed and agitated to achieve homogenization, and the mixing and agitation is carried out at an agitation speed of 1,000 to 7,000 rpm for 1 to 60 min.  
   
   
       10 . The method of preparing a latex of  claim 9 , wherein the agitation speed in the agitating and heating the homogenized solution is 100 to 800 rpm, and the heating temperature is 50° C. to 80° C.  
   
   
       11 . The method of preparing a latex of  claim 10 , wherein a polymerization initiator is added to the homogenized solution and is a water-soluble polymerization initiator selected from the group consisting of a persulfate, an azo based compound and a peroxide compound.  
   
   
       12 . The method of preparing a latex of  claim 11 , wherein the polymerization initiator is used in 1 to 5 parts by weight based on 100 parts by weight of the homogenized solution.