GB1430796A - Process for preparing polymer fibres - Google Patents

Abstract

1430796 Polymeric fibres CROWN ZELLERBACH INTERNATIONAL Inc 16 March 1973 [20 March 1972] 12785/73 Heading B5B Polymeric fibres for making paper are produced by forming an emulsion of water dispersed in a polymer in the presence of an emulsifying agent and a solid hydrophilic dispersing aid at autogenous or higher pressure and at a temperature above the melting point of the polymer but below the critical temperature of water, and rapidly passing the emulsion through an orifice into a region of lower pressure to adiabatically vaporize the water and form fibres of polymer. The polymer has a melting- point above the normal boiling point of water. The polymer may be ethylene, propylene, 4- methyl, 1-butene, 1-pentene, pentene-1, vinyl cyelohexane, styrene, nylon-66, polyurethane, or polyethylene terephthalate, or a mixture or copolymer thereof. The polymer may be crystalline and has a melt viscosity less than 500 cp. 0À1 to 20% (by wt. of polymer) of the emulsifying agent is present, and the agent has an HLB value less than 7À0, e.g. calcium or aluminium stearate, cellulose ether, "Span" (Registered Trade Mark), amine salts of alkyl aryl sulphonate or alkyl sulphate, bis-(alkyl)- sulphosuccinate monovalent salts, alkyl aryl polyethyleneglycol, alkyl polyethyleneglycol, and esters of fatty acids. 1À0 to 25% (by wt. of polymer) of the dispersing aid is also included, e.g. bentonite clay, fuller's earth, diatomaceous earth, silica aerogel, or pyrogenic silica. The emulsion normally contains 15 to 45% (by wt. of polymer) of water, and may be formed by blending finely divided polymer (passing through 50 U.S. standard mesh screen) with the other components before heating above melting point, and may be raised to 100 to 1000 p.s.i. above autogenous pressure by nitrogen. The emulsion may itself be dispersed in a quantity of water to form a "dual emulsion". The process may be performed batchwise or continuously.