Open cell thermoplastics e.g. for filters and noise dampers - made by compressing thermoplastics with polar organic liq. and heating

摘要

Prodn. of open-celled polymer materials comprises (i) compressing a powdery thermoplastic polymer (I), under 10-250 kp/cm2 applied pressure, in the presence of 5-30 (10-20 wt. % w.r.t. (I), of an organic polar liq. (II), the b.pt. of which lies 5-20 degrees C above the softening point of (I), and then (ii) heat-treating the compsn. at the softening point of (I) at a heating rate of 20-190(30-80) degrees C/min. Prods. can be used as (a) gas-permeable insulators and constructional materials, (b) as pneumatic noise dampers in machine-building, (c) as pressure mixers in purifying waste waters and in water tank aeration; (d) as carriers for liq. extractants in metal extn.; (e) as filters for gases and liquids, including aggressive liquids, bio-masses, blood, cellulose ester dopes, lacquers, enamels and polyurethane solns. The prods. allow filtration at high pressures, repeated sterilisation and regeneration with solvents, acids and alkali.