Melt extrusion process
AssigneeGeneral Electric Company
InventorWilliam P. Enlow
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Abstract
Melt extrusion processes involving phosphite stabilized polyolefin compositions subject to solid by-product formation during melt extrusion are improved by the addition of an epoxidized ester of a fatty acid to the composition. The processes involving the improved compositions exhibit reduced levels of screen pack plugging during fiber and film extrusion processes than that achieved with fatty acid salts, such as calcium stearate.
Claims10
An extrusion process for making plastic articles, said process comprising:
- a) forming a polyolefin composition comprising a polyolefin resin, a phosphite stabilizer, and at least one epoxidized ester of a fatty acid,
- b) melt extruding said composition through a filtration system to produce a filtered polyolefin melt stream,
- c) passing said melt stream through a die to make the plastic article, wherein said phosphite is a bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite.
A melt extrusion process for making polypropylene fibers, said process comprising:
- a) forming a polypropylene composition comprising a polypropylene resin, bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite, and an epoxidized ester of a fatty acid,
- b) melting said composition to form a melted composition,
- c) filtering said melted composition to remove unmelt solids,
- d) passing said filtered composition through a fiber forming die orifice to produce polypropylene fiber.
A melt extrusion process for making polypropylene fibers, said process consisting essentially of:
- a) forming a polypropylene composition comprising a polypropylene resin, bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite, and an epoxidized ester of fatty acid,
- b) melting said composition to form a melted composition,
- c) filtering said melted composition to remove unmelt solids,
- d) passing said filtered composition through a fiber forming die orifice to produce polypropylene fiber.
Dependencies are inferred from the claim text.