Huels Aktiengesellschaft

Chemische Werke Huls Aktiengesellschaft

Hans-Joachim Panoch

Martin Bartmann

Roland Feinauer

Rainer Feldmann

Jurgen Finke

Heinz Scholten

Markus Wenzel

The invention relates to molding compositions which are stable with respect to alcohol and boiling water. The known molding compositions which are stable to boiling water and comprise amorphous copolyamides have unsatisfactory stability to alcohols. There is therefore a demand to improve molding compositions comprising polyamide in this respect. The invention provides molding compositions based on an amorphous copolyamide prepared from:

Molding compositions which are stable to alcohols and boiling water

The invention relates to molding compositions which are stable with respect to alcohol and boiling water. The known molding compositions which are stable to boiling water and comprise amorphous copolyamides have unsatisfactory stability to alcohols. There is therefore a demand to improve molding compositions comprising polyamides in this respect.

Molding polyamide composition which are stable to alcohols and boiling

Polylaurolactam powder coating compositions for the coating of metals at high temperatures are obtained by grinding low molecular weight and brittle polylaurolactam with subsequent condensation by heating of the powder to temperatures of below its melting point. A. For the production of pigment free polylaurolactam powders, the low molecular weight granules are ground at temperatures of between 0.degree. and 45.degree. C. which have a relative viscosity of between 1.25 and 1.45 (measured in a 0.5 percent mecresol solution at 25.degree. C.) and have been produced by the polymerization of laurolactam in the presence of 2-10 percent by weight of water, 0.3-0.7 percent by weight of phosphoric acid at temperatures of between 265.degree. and 300.degree. C. in the absence of chain stabilizers under internal pressure, with subsequent granulating, and extraction between 25.degree. and 70.degree. C. with methanol or ethanol. The subsequent condensation is conducted at temperatures of between 140.degree. C. and below the melting point of the polyamide to relative viscosity value of between 1.55 and 1.65; and finally the powders obtained are brought to a particle size distribution of between greater than 60 and less than 350 microns. B. For the production of pigmented polylaurolactam powders, the low molecular weight granules are treated at temperatures of between 110.degree. and 140.degree. C. and pressures of between 5 and 8 bars with the addition of pigments in primary aliphatic alcohols having 1-3 carbon atoms, cyclohexanol, or ethylbutanol, these granules having a relative viscosity of between 1.25 and 1.65 and likewise having been obtained by the polymerization of laurolactam in the presence of 2-10 percent by weight of water, 0.3-0.7 percent by weight of phosphoric acid at temperatures of between 265.degree. and 300.degree. C. in the absence of chain stabilizers under internal pressure, with subsequent granulating, and extraction between 25.degree. and 70.degree. C. with methanol or ethanol. The powders are obtained with gradual cooling to room temperature with a minimum of mechanical motion and these powders are dried, optionally screened and, if necessary, the thus-extracted granules or the dried powders are brought to relative viscosity value of between 1.55 and 1.65 by subsequent condensation at temperatures of between 140.degree. C. and below the melting point of the polyamide.

Method for producing polylaurolactam powder compositions for the coating

Polylaurolactam powder coating compositions for the coating of metals at high temperatures are obtained by grinding low molecular weight and brittle polylaurolactam with subsequent condensation by heating of the powder to temperatures of below its melting point. A. for the production of pigment free polylaurolactam powders, the low molecular weight granules are ground at temperatures of between 0.degree. and 45.degree. C. which have a relative viscosity of between 1.25 and 1.45 (measured in a 0.5 percent m-cresol solution at 25.degree. C.) and have been produced by the polymerization of laurolactam in the presence of 2 - 10 percent by weight of water, 0.3 - 0.7 percent by weight of phosphoric acid at temperatures of between 265.degree. and 300.degree. C. in the absence of chain stabilizers under internal pressure, with subsequent granulating, and extraction between 25.degree. and 70.degree. C. with methanol or ethanol. The subsequent condensation is conducted at temperatures of between 140.degree. C. and below the melting point of the polyamide to relative viscosity value of between 1.55 and 1.65; and finally the powders obtained are brought to a particle size distribution of between greater than 60 and less than 350 microns. B. for the production of pigmented polylaurolactam powders, the low molecular weight granules are treated at temperatures of between 110.degree. and 140.degree. C. and pressures of between 5 and 8 bars with the addition of pigments in primary aliphatic alcohols having 1 - 3 carbon atoms, cyclohexanol, or ethylbutanol, these granules having a relative viscosity of between 1.25 and 1.65 and likewise having been obtained by the polymerization of laurolactam in the presence of 2 - 10 percent by weight of water, 0.3 - 0.7 percent by weight of phosphoric acid at temperatures of between 265.degree. and 300.degree. C. in the absence of chain stabilizers under internal pressure, with subsequent granulating, and extraction between 25.degree. and 70.degree. C. with methanol or ethanol. The powders are obtained with gradual cooling to room temperature with a minimum of mechanical motion and these powders are dried, optionally screened and, if necessary, the thus-extracted granules or the dried powders are brought to relative viscosity value of between 1.55 and 1.65 by subsequent condensation at temperatures of between 140.degree. C. and below the melting point of the polyamide.

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Haltern, Germany

Hans-Joachim Panoch