Abstract: A method is provided for removing paint from plastic parts by treating the painted part with a solvent mixture. The solvent mixture used to remove the paint is a mixture of a high-boiling pyrrolidone or piperidone (lactam) solvent and an aqueous mineral acid, optionally with a surfactant added.

Abstract: 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 “rinse” polymer (e.g., polyethylene) may be added so as to remove any vestigial amount of the gel purge formulation therefrom.

Abstract: 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 “rinse” polymer (e.g., polyethylene) may be added so as to remove any vestigial amount of the gel purge formulation therefrom.

Abstract: 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 “rinse” polymer (e.g., polyethylene) may be added so as to remove any vestigial amount of the gel purge formulation therefrom.

Abstract: 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 “rinse” polymer (e.g., polyethylene) may be added so as to remove any vestigial amount of the gel purge formulation therefrom.

Abstract: 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.

Abstract: 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.

Abstract: A process for making hot melt adhesive compositions comprising the steps of:(a) dissolving hot melt adhesive components into a room temperature or higher solution of a water soluble substituted (e.g. NMP) to form a water soluble substituted lactam (e.g. NMP)/hot melt adhesive component solution;(b) adding said solution formed in step (a) into water to form a solid;(c) extracting out the water soluble substituted lactam (e.g. NMP) from said solid formed in step (b);(d) drying of said solid wherein water soluble substituted lactam e.g. NMP, is leached out as in step (c) to form the hot melt adhesive.

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

Abstract: 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.

Abstract: 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.