Basf Corporation

Mark W Waldrop

William C Walsh

Lawrence E James

Ulrich Abel

William Monahan

Tom A Hazenstab

Methods for cleaning screw extruder, especially powder-coating extruders, include filling the extruder barrel with a gel purge formulation comprised of a high-boiling pyrrolidone or piperidone (lactam) solvent (most preferably N-methyl pyrrolidone (NMP)), thickened with 5-50 wt. % of a thermoplastic resin thickening agent, most preferably polystyrene (PS). Once the extruder barrel is filled with the gel purge formulation, the screws are stopped and the gel allowed to soak for between about 10 to about 30 minutes. The screws are then restarted and the gel is discharged from the extruder. Immediately after the gel purge formulation exits the machine, a small amount of a thermoplastic &ldquo;rinse&rdquo; polymer (e.g., polyethylene) may be added so as to remove any vestigial amount of the gel purge formulation therefrom.

Gel purge formulations and methods of cleaning extruders by using the same

Disclosed is a PVC pipe cement composition that comprises a polymeric material of a methyl methacrylate homopolymer or copolymer, a styrene-acrylonitrile polymer, and a rubber grafted with at least a methacrylic acid ester of a C to C alkanol; and at least about 10% by weight solvent. The pipe cements of the invention form strong welds or bonds and have lower volatile organic content as compared to currently used materials

MABS-based PVC pipe cement

This invention relates to a plastics processing equipment cleaning compound comprising a hard outer shell made from a thermoplastic resin and a soft inner core containing a substituted pyrrolidone.

Substituted pyrrolidone plasticized thermoplastic resin useful as a

A process for making hot melt adhesive compositions comprising the steps of:

Process for making hot melt adhesives using water soluble substituted

Disclosed is a solvent-based cement for bonding joints of polyvinyl chloride pipe and fittings. The cement of the composition contains at least about 10% by weight of a polyvinyl chloride resin, at least about 2% by weight of a solid alcohol having a melting point above at least about 20.degree. C., and at least about 10% by weight of a solvent or a mixture of solvents. There is also provided a method of joining two pieces of thermoplastic material, such a poly(vinyl chloride) piping and fittings, and the product piece having one or more joints formed thereby.

Solid alcohol-filled PVC pipe cement

The present invention is directed to a method of removing polymer residue from chemical processing equipment, comprising contacting said residue with NMP vapors.

Method of cleaning polymer residues with NMP

There is now provided a solvent cement having a total of less than 80 weight percent of solvents and a thermoplastic polyurethane elastomer as at least one of the resins dissolved in the solvent. The solvent mixture contains at least a 5- or 6-membered water miscible lactone or lactam such as N-methyl-2-pyrrolidone (NMP) in an amount of 21 weight percent or less based on the weight of all the ingredients. The reduced solvent concentration assists in lowering VOC emissions while preserving the hydrostatic burst strength mechanical property required by ASTM D 2564-88.

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Royal Oak, MI, United States of America

Mark W Waldrop