| 主权项 |
1. A method to make an aqueous pour point depressant dispersion composition consisting of:
i) an ethylene vinyl acetate copolymer (EVA) in an amount of from 12 to 50 weight percent; ii) a dispersing agent in an amount of from 1 to 10 weight percent; said dispersing agent consisting of one or more of:
a) a fatty acid/salt having the formula R1COOR2 wherein R1 is a straight chain, saturated or unsaturated, hydrocarbon radical of 8 to 25 carbon atoms and R2 is H or a base-forming radical;b) an alkyl, arene and/or alkylarene sulfonate;c) a salt of a polymer of alkyl acrylate and/or alkyl methacrylate and acrylic and/or methacrylic acid, or a salt of partial esters of maleic anhydride-styrene copolymers;d) a cationic surfactant;e) a zwitterionic surfactant;orf) a nonionic surfactant; iii) water; iv) optionally an aqueous freezing point depressant; v) optionally a stabilizing agent; and vi) optionally an additional additive selected from a biocide, a colorant, an anti-foaming agent, or a mixture thereof,wherein weight percents are based on the total weight of the aqueous pour point depressant dispersion composition, comprising the steps of:
a) adding the EVA (i) and dispersing agent (ii) to an extruder having a mix and convey zone, an emulsification zone, and a dilution and cooling zone; b) forming a resin melt by melt kneading (i) and (ii) together in the mix and convey zone; c) delivering the resin melt to the emulsification zone; d) adding water (iii) and a base to the resin melt in the emulsification zone to form an aqueous dispersion of EVA; e) passing the aqueous dispersion of EVA through the dilution and cooing zone; and f) forming the aqueous pour point depressant dispersion. |
