| 摘要 |
Water in oil dispersions of hydrophilic polymers based on acrylic acid partially or totally converted into the salt form with ammonia are disclosed for use in formulating printing pastes for colour printing. The water in oil dispersions are characterized by 65 to 75% of an aqueous dispersed phase, 3 to 7% of an emulsifying system having overall an HLB value greater than 7, and the remainder (up to 100%) being an oil phase. Approximately 35 to 50% of the aqueous dispersed phase is constituted by a hydrophilic polymer having a molecular weight greater than 3,000,000 formed, in molar proportions, from 0 to 50% acrylamide, 0.008 to 0.1% bisacrylamidoacetic acid partially or totally converted into the salt form with ammonia, and the remainder acrylic acid, of which 65 to 100% is in the form of ammonium acrylate. The emulsifying system constituted by a mixture of at least three surface active agents of which more than 50% by weight is contributed by at least one surface active agent having an HLB between 3 and 5, and the complement to 100% being contributed by at least two surface active agents individually having an HLB between 11 and 14. The oil phase constituted by one or a plurality of hydrocarbons which are liquid at ambient temperature, containing less than 20% by weight of aromatic hydrocarbons and having simultaneously a density, determined at 20.degree.C, greater than 0.8 g/cm3, a kinematic viscosity, determined at 20.degree.C, greater than 10 mm2/s and a boiling point above 250.degree.C.
|
