E.i. Dupont De Nemours and Company

Marlin D Buckmaster

Stuart Karl Randa

Richard A Morgan

Paul Gregory Bekiarian

Donald Leonidas Henry

Extrusion rheology of thermoplastic polymer as manifested by surface smoothness is improved by incorporating foam cell nucleating agents into the polymer and extruding the polymer under laminar flow to form unfoamed extrudate.

High speed extrusion

Fluoropolymer having unstable end groups is used to form foamed fluoropolymer structures without added blowing agent.

Self-foaming fluoropolymer composition

A foam cell nucleating agent that is a combination of sulfonic or phosphonic acid or salt thereof and inorganic salt containing a polyatomic anion yields improved foaming of thermoplastic resins such as polyolefins and melt-fabricable fluoropolymers.

Two-part nucleating agent system

Extrusion theology of thermoplastic polymer as manifested by surface smoothness is improved by incorporating foam cell nucleating agents into the polymer and extruding the polymer under laminar flow to form unfoamed extrudate.

An improved foam nucleation system based on selected boron nitride provides smaller foam cell size for melt-fabricable fluoropolymers.

Foamable fluoropolymer composition

Thermally and hydrolytically stable fluorocopolymers, especially melt-processible fluorocopolymers, for example, tetrafluoroethylene/hexafluoropropylene copolymers, having --COOH and/or --COF groups on the polymer chains are contacted and reacted with a secondary or tertiary amine and heated at 160.degree. -400.degree. C. for a time sufficient to convert --COOH and/or --COF groups to stable --CF.sub.2 H groups, the resultant stabilized copolymers being useful, for example, in electrically conductive compositions having a good combination of melt flow and electrical conductivity.

Process for the stabilization of fluoropolymers

Melt-processible copolymers of at least two halogenated comonomers from a defined class, especially perhalogenated comonomers, and particularly perfluorinated comonomers, of improved thermal stability are obtained by first contacting the copolymers with a stabilizing agent selected from bases (ammonia or amines) having a boiling point at normal pressure of at most 130.degree. C. and tertiary alcohols having up to 8 carbon atoms, to form an intermediate, drying the intermediate at about 70.degree.-150.degree. C., and fluorinating the intermediate at a temperature between 20.degree. C. and the lowest temperature at which the copolymer exhibits a solid state transistion, then removing excess fluorine and by-products and recovering the stabilized copolymer. Such stabilized copolymers are useful for a variety of technically important applications, including as cladding for optical fibers, substrates for electronic components, thermal laminates, pipes, tubes, and fittings, etc.

This invention relates to the use of a special class of sulfonic and phosphonic acids, and salts of the acids, to give improved nucleation for foam extrusion of thermoplastics using either dissolved gas or chemical blowing agents to produce foam.

Nucleating agents for thermoplastic resins

Melt-processible copolymers of at least two halogenated comonomers from a defined class, especially perhalogenated comonomers, and particularly perfluorinated comonomers, of improved thermal stability are obtained by first contacting the copolymers with a stabilizing agent selected from bases (ammonia or amines) having a boiling point at normal pressure of at most 130.degree. C. and tertiary alcohols having up to 8 carbon atoms, to form an intermediate, drying the intermediate at about 70.degree.-150.degree. C., and fluorinating the intermediate at a temperature between 20.degree. C. and the lowest temperature at which the copolymer exhibits a solid state transition, then removing excess fluorine and by-products and recovering the stabilized copolymer. Such stabilized copolymers are useful for a variety of technically important applications, including as clading for optical fibers, substrates for electronic components, thermal laminates, pipes, tubes, and fittings, etc.

Process for the setabilization of fluoropolymers

This invention relates to foamable melt processible fluoropolymer resins containing boron nitride and one or more of a class of inorganic salts which significantly enhance foam nucleation (as evidenced by small foam cell size).

Foam nucleation system for fluoropolymers

Melt-processible tetrafluoroethylene/perfluoroolefin copolymer granules, and process for their preparation, are disclosed having improved thermal stability, high purity and reduced bubble tendency.

Melt-processible tetrafluoroethylene/perfluoroolefin copolymers and

This invention relates to a process for preparing melt-processible tetrafluoroethylene perfluoro(alkyl vinyl ether) (TFE/PAVE) copolymer granules having good particle flow characteristics and thermal stability, and to the product of the process.

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Vienna, WV, United States of America

Marlin D Buckmaster