Basf Aktiengesellschaft

Basf Se Corporation

Thomas Sauer

Gunter Pipper

Christoph Plachetta

Axel Wilms

Gerhard Wegner

Alfons Ludwig

Rainer Neuberg

Jens Becker

Achim Gerstlauer

Reinhard Lang

Horst Egly

Walter Caseri

Hans-Harald H&uuml;nger

A process for continuously preparing copolyamides from lactams and salts of diamines and dicarboxylic acids, in which lactams together with salts of diamines and dicarboxylic acids are passed from the top downward through a vertical polymerization tube at polyamide-forming temperatures, which comprises

Process for continuously preparing copolyamides from lactams and salts of diamines and dicarboxylic acids

The disclosure is a process for preparing polyamides by concentrating the wash water extract from the extraction of polyamide to an extractables content of not more than 85% by weight, adding fresh lactam down to a water content of from 0.5 to 13% by weight, and effecting at least one adiabatic expansion during the polymerization.

Preparation of polyamides

The disclosure is a process for recovering caprolactam monomer and oligomer from aqueous polycaprolactam extracts by removing the inorganic contaminants present therein.

Recovery of caprolactam monomer and oligomer from aqueous

Novel polymers contain phthalocyanine ring systems bonded via axial bonds to a central metal atom in the polymer chain and consist of repeating units of the general formula (I) ##STR1## In the general formula (I), Pc.sup.s is a phthalocyanine ring system having peripheral substituents, Me is the central atom of the phthalocyanine ring system, which atom is bonded in the polymer main chain, suitable central metal atoms Me being silicon and germanium, R is alkylene, R' and R' are each alkyl, cycloalkyl, aryl or alkoxy and Z is a silicon-carbon bond or further Si-containing groups. The novel polymers can be particularly advantageously used for the production of ultrathin layers by the LB technique, optically transparent films having high optical anisotropy and a high volume concentration of phthalocyanine radicals being formed.

Polymers having phthalocyanine units and their use as optically

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Dirmstein, Germany

Thomas Sauer