Basf Aktiengesellschaft

Franz Zahradnik

Rainer Theysohn

Gunter Pipper

Graham E McKee

Horst Reimann

Rolf Wurmb

Claus Cordes

Rolf Steinberger

Walter Ziegler

Franz Schmidt

Hans-Peter Weiss

Wolfgang Seydl

Karlheinz Ulmerich

Richard Pflueger

Farid Rizk

Hans Georg Dorst

Josef G Floss

Manfred Liebscher

Klaus J Tischendorf

Polyamide granules are dried and heated by feeding a suspension of granules in water into a sieve (1), where the bulk of the water is removed, and then into a tower dryer (10), where they are deposited in bed form and then freed of the remaining water while moving in plug flow under the force of gravity with a counter-current inert gas stream at from 70.degree. to 200.degree. C. The tower dryer possesses an inlet at the top (11) and outlet at the bottom (34) for the granules and also feed lines (20, 22, 31) for the inert gas. To achieve a uniform degree of drying of the granules, the inert gas is divided on entry into the tower dryer at a point between the drying zone and the heating zone into a stream which flows radially inward into the bed of granules on the one hand and a stream which flows radially inward and outward on the other. In this way the inert gas is distributed particularly uniformly and the granules are dryable in a very short drying zone down to a water content of 0.0001 kg of water/kg of polymer. The lower, conically tapered area of the tower dryer--bin 30--ensures a uniform rate of descent of the granules and hence a uniform solid-phase condensation with a favorable molecular weight distribution. The tower dryer (10) is followed by a fluidized bed cooler (41) in which the granules are cooled with air to &lt;50.degree. C.

Drying and heating of polyamide granules

High-impact polyamide molding compositions contain as essential components

Polyamide compositions containing alkyl orthotitanate or dialkyltin

Nylon granules having an outer shell

A process for the preparation of high-impact nylon molding materials, containing 30-88% by weight of a thermoplastic nylon, 10-50% by weight of an organosilane-coated silicate reinforcing filler, 0.1-5% by weight of a polyurethane ionomer, 2-30% by weight of a carboxyl-containing thermoplastic elastomer and, where appropriate, effective amounts of conventional additives, by mixing the silicate filler, coated with an organosilane and a polyurethane ionomer, with the thermoplastic elastomer and the nylon at above the melting point of the nylon, wherein, in a first stage, the silicate filler coated with an organosilane and a polyurethane ionomer is mixed with the nylon at above the melting point of the latter, and in a second stage the thermoplastic elastomer is finely dispersed in the filler-containing nylon at above the melting point of the latter.

Preparation of high-impact nylon molding materials

Polylactams are prepared continuously by a process in which a lactam containing from 1 to 25% by weight of water is heated in a prepolymerization zone under a pressure of from 1 to 10 bar at from 220.degree. to 280.degree. C. for 1 to 10 minutes, water being vaporized at the same time, with the proviso that the degree of conversion on emergence from the prepolymerization zone is not less than 85%, the prepolymer and the vapor are separated continuously, and the prepolymer is passed into a polymerization zone and is polymerized further under superatmospheric pressure at from 240.degree. to 290.degree. C.

Continuous hydrolytic preparation of polylactams

Nylons are prepared by a continuous process in which, in an evaporator 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 vapors are separated continuously, the vapors are rectified and the entrained diamines are recycled, and the prepolymer is fed to a polycondensation zone and subjected to polycondensation under superatmospheric pressure of from 1 to 10 bar and at from 250.degree. to 300.degree. C., wherein the aqueous salt solution is heated under superatmospheric pressure of from 1 to 10 bar during a residence time of less than 60 seconds, with the proviso that, on leaving the evaporator zone, the degree of conversion is not less than 93% and the water content of the prepolymer is not more than 7% by weight.

Continuous preparation of nylon with diamine recycling

Filled nylon molding compositions of increased rigidity containing red phosphorus as a flameproofing agent and talc or mica as a filler. They may be converted to moldings which are used, above all, in the electrical industry.

Flameproof nylon molding compositions

A process for the manufacture of polyamides from .epsilon.-caprolactam and/or other polyamide-forming starting compounds by polymerization and subsequent extraction of the polymer. The extract containing solvent, monomer and oligomers is concentrated in the absence of atmospheric oxygen, the surfaces which come into contact with the extract being made of materials which are inert under the conditions of the concentration process, and the concentrate, without further purification or separation, is polymerized by itself or together with other polyamide-forming starting compounds.

Manufacture of polyamides

Growing community of inventors

Ludwigshafen, Germany

Franz Zahradnik