Abstract: A pressure spring for tape cassettes which consists of a spring steel strip which is, in particular, narrow and is of roughly uniform width comprises a flat central part and curved spring arms adjacent to said part and having a continuous curve. The flat central part has, as fastening parts, holes with indented fastening collars which, together with rivet pegs and recesses in a housing wall, form a roughly projection-free spring fastening, the riveted peg ending roughly at the spring surface. The pressure spring exhibits a straight line with a defined slope in the operating region of its spring characteristic. The pressure spring can be used for tape cassettes of all types, in particular for video cassettes.

Abstract: A process for removing volatile constituents from polymer melts or pastes, wherein the polymer or paste containing the volatile constituents is passed, with continuous formation of fresh surfaces, through one or more zones in which the volatile constituents evaporate, and the volatile constituents are removed from the zone or zones in which they evaporate through, in each case, a plurality of porous orifices, and an apparatus for carrying out said process.

Abstract: Nylons are prepared by a continuous process in which, in a precondensation zone, an aqueous solution of a salt of a dicarboxylic acid of 6 to 18 carbon atoms and a diamine of 6 to 18 carbon atoms is heated to 250.degree.-300.degree. C. under superatmospheric pressure, with simultaneous vaporization of water and formation of a prepolymer, the prepolymer and the vapor are separated, and the former is fed into a polycondensation zone and condensed under superatmospheric pressure of from 1 to 10 bar and at from 250.degree. to 300.degree. C., wherein the aqueous salt solution is condensed under superatomspheric pressure of from 1 to 10 bar in the first third of the tubular precondensation zone provided with baffles, until the degree of conversion is not less than 93%, and the prepolymer and the vapor phase are brought into intimate contact with one another in the remaining two thirds of the precondensation zone.