Thickened latex-pigment dispersions

There are numerous applications where the development of high viscosity is necessary in a finished product. For example, thickeners, mainly based on poly(acrylic acid), are used to give body to so-called emulsion paints. Emulsion paints are not formulated from true emulsions (Le. stable dispersions of organic liquids in water), but are prepared from latexes, that is, dispersions of polymer in water. Since latexes do not contain soluble polymers, they have a viscosity almost the same as pure water. As such, they would not sustain a pigment dispersion, but would allow it to settle they would also fail to flow out adequately when painted on to a surface. Inclusion of a thickener in the formulation gives a paint in which the pigment does not settle out and which can readily be applied by brush to a surface. 

Poly(acrylic acid) is water soluble. Because of its water solubility and its ability to increase the viscosity of water, it is used as a thickener. It is also a good flocculent for sewage treatment and is added as a pigment dispersant in latex paints, and is used in binders and adhesives. Polymers and copolymers containing acrylic or/and methacrylic acid are manufactured at a rate of about 2,000,000 metric tons yearly. 

The dispersion stability can be increased due to thickeners added, e.g. ethoxylated urethanes, which are able to form associates with the film forming latex [201]. At the same time, the dispersion contains a certain amount of surfactants these is free surfactant present in the latex, and added surfactant to disperse pigments and fillers. Stability is achieved by varying interaction with the two dispersed phases - latex particles associated with the thickener, and pigment particles. 

Uses Dispersant, stabilizer for high solids min. slurries thickener for nat. rubber latex coatings pigment dispersant in coatings food-contact paper/paperboard... 

Uses Emulsifier, plasticizer, lubricant, wetting agent, dispersant, binder, thickener for emulsion polymerization, dry cleaning, textiles, leather, min. oil emulsions, paper industry, wall-tile mastics, solvent emulsions, aq. systems pigment dispersant in latex paints solubilizer for essential oils coupling agent, solubilizer, emulsifier for o/w creams and lotions... 

GeneraL Claiiflcation and thickening duties, recycling of pigment dispersions, latex product recovery and concentration. 

Inorganic pigment dispersant— photographic films Emulsifier—latex polymerization Ag halide emulsion stabilizer Thickeners, emulsifiers Cellulose nitrate latex stabilizer Inorganic pigments dispersant— photocopying Textile finishes dispersant Dispersant, thickeners polyamide dyes... 

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