Pigment dispersions stabilization

Uses Pigment dispersant, stabilizer for aq. systems incl. emulsion paints, plastic disps. 

Chem. Descrip. Polymeric agent in water and DEA Uses Pigment dispersant, stabilizer for inorg. pigments, in aq. paints, flexographic aq. inks, disps. based on water... 

Uses Pigment dispersant, stabilizer, wetting agent for silica matting aid disps., radiation-cured coatings and inks, U V wood coatings, disps. based on UV monomers... 

Uses Pigment dispersant, stabilizer in aq. paints, decorative paints, industrial paints... 

Uses Dispersant for low color applies., calcium sensitive systems, pigment dispersions stabilizer for emulsion polymerization water reducer for metal oxides, specialty dispersions... 

Pigment dispersion stability, room temperature film formation, and ink re-solu-bihty are important properties to consider in the design of emulsion polymers for printing ink. A support resin (Sect. 5.2.2) is used in most ink grade emulsions to maintain these properties. The support resin is a low to medium molecular weight styrene acryHc or other water soluble resin. It comprises up to 60 % solids content of the emulsion and replaces up to 90 % of surfactant stabilizers. 

Solution vehicles consist of water soluble polymers not manufactured by emulsion polymerization. The solution vehicle is an alkali soluble polymer in aqueous solution or a blend of polymers with combined properties into a single waterborne varnish. Soluble polymers are made by free radical polymerization in a processing solvent or as addition or condensation products with heat reaching temperatures up to 265 °C. Solution vehicles are mixtures of soluble resins unlike emulsion polymers. A solution vehicle is used to increase adhesion to film and improve ink printabihty or transfer to meet specific performance requirements. The solution vehicle provides pigment dispersion stabilization, transparency, low film forming temperature, gloss and re-solubility. An alkali soluble resin is a carboxylic acid functional polymer neutralized (solubilized) with ammonia, amine or sodium hydroxide. The add numbers are generally above 100. Ammonia or volatile amines are used in most aqueous inks except for news print inks. After evaporation of the amine, the resin becomes insoluble and resistant to water spray or other water contact. The ink is re-solubilized with alkaline water for the clean-up cycle. For news print ink, the polymers are solubiHzed with sodium hydroxide to maintain re-solubility (open time) of the ink on the press. News print ink pressman prefer unlimited open time and fewer clean-up cycles. Water resistance is not required since ink penetrates the news print paper fibers. 

Pigment dispersions are stabilized by charge repulsion and entropic, ie, steric or osmotic, repulsion. Although both types of stabilization force may be present in most cases, for pigment dispersions in solvent-bome coatings entropic repulsion is usually the most important mechanism for stabilization. 

Colorant containing annatto and Ca caseinate as carrier mixed with water to be added directly to cheese milk yielding uniform colored cheese mass Water-dispersible beadlet of p-carotene is mixed with oil to attein composition that remains stable even in presence of polyphosphates and with antioxidant action even in absence of ascorbic acid Blending carotenoid pigment and soybean fiber (wifii tomato juice) as effective ingredient for dispersion stability... 

Isohexides exhibit excellent properties as plasticizers for polyvinyl alcohol polymers.2 Compounds obtained from isosorbide and trialkylaluminum proved to be highly active cocatalysts for polymerization of alkenes. Such derivatives, which were supposed to be oligomeric O-aluminum-isosorbides, are of glass-like appearance and exhibit pyrophoric properties.255 Isosorbide is a component of mixtures used for water-based pigment inks, having excellent dispersion stability, which is necessary for ink-jet printing.256 257... 

Although cholesterol is essentially insoluble in water, a soluble cholesterol derivative can be formed by reacting it with high levels of ethylene oxide.66,67 This ethoxylated product has balanced hydrophobic and hydrophilic properties. The increased hydrophilicity makes it useful as an oil-inwater emulsifier or as a stabilizer. Ethoxylated lanolin is used for viscosity regulation, pigment dispersion, and as a solubilizer. Less than 1% ethoxylated cholesterol is effective at reducing the viscosity of anionic lotions to make them easier to pour. Non-ionic systems require more ethoxylated cholesterol for this purpose 68... 

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