Abstract: An aliphatic polyester and/or copolyester, obtained from a polyreaction of at least one monomer from the group comprising lactides, lactones, cyclic carbonates and cyclic anhydrides. To be able to prepare the aliphatic polyester and/or copolyester a reaction mixture is used which contains at least one catalyst of the general formula (M) (X.sub.1, X.sub.2 . . . X), M being a metal selected from the group 3 to 12 of the periodic system (X.sub.1, X.sub.2 . . . X.sub.m) being a substituent selected from one of the families of alkyls, aryls, oxides, carboxylates, halogenides, alkoxides and compounds with elements from group 15 and/or 16 of the periodic system, m being an integer in the range of from 1 to 6, and n being an integer in the range of from 0 to 6, and which also contains a co-catalyst of the general formula (Y) (R.sub.1, R.sub.2 . . . R.sub.q).sub.p, Y being an element selected from the group 15 or 16 of the periodic system. (R.sub.1, R.sub.2 . . . R.sub.

Abstract: A polymer material (6) is formed from a first polyethylene component (1) having a low density (VLDPE) which is silane-grafted with an organic silane (3) in combination with organic peroxide (4) and is cross-linked through storage in a damp environment and/or in water. The polymer material (6) can be processed into medical instruments under dry conditions prior to cross-linkage. After cross-linkage the medical instruments made from the polymer material (6) exhibit a high degree of transparency, are non-buckling and flexible. The polymer material (6) is produced in an extruder, preferentially in a double-worm extruder.

Abstract: A method and an apparatus have been found, with the aid of which important properties can be determined during the extrusion of polymer melts:continuous measurement of the density of pure polymers (density constancy)plotting of p, v, T diagrams of plastics determination of percentagesf by volume and weight in polymer/filler or polymer/reinforcing agent mixturesdetermination of proportions by weight of pigment in masterbatch preparationdetermination of measuring data for statements going further regarding mixing and thermal homogeneity of the material.Furthermore, the apparatus as a sensor is suitable as basic module for a closed control loop for monitoring and keeping constant porportions of filler.

Abstract: The wear on machine components is reduced during processing of solids concentrates containing abrasive solids if solids concentrates in which the carrier material has a resistance to shear and/or deformation which is the same as or higher than that of the polymer to be provided with the solids concentrate are employed.

Abstract: An injection stretch-blow molding apparatus is disclosed. The apparatus includes at least two preform conditioning stations, a molding injection station for initially molding the preform and a blow molding station. Each of the stations is preferably able to process an equal number of preforms at once. The apparatus also includes a turntable and preform supporting jaws connected to the turntable for transporting consecutive sets of preforms made at the injection station to the two conditioning stations alternately, and for transporting sets of preforms alternately from each of the conditioning stations to the blow molding station. This allows all four stations to operate at their respective full capacities, even though conditioning at the conditioning station requires up to twice as long as injection molding or stretch-blow molding.