초록 ▼

A process for making an extruded foamable composition is disclosed where the foamable composition includes a partially-crystalline melt processible perfluoropolymer and a foam nucleating package. The process makes a foamed product having uniform foam cell size at high speeds without loss of product

A process for making an extruded foamable composition is disclosed where the foamable composition includes a partially-crystalline melt processible perfluoropolymer and a foam nucleating package. The process makes a foamed product having uniform foam cell size at high speeds without loss of product quality.

대표청구항 ▼

1. An extrusion foaming process comprising extruding a foamable composition at a line speed of 1,000 feet per minute or greater on to a conductor to form a layer of foamed composition on said conductor, said layer having foam cells concentrated towards the center of said layer, whereby said layer ha

1. An extrusion foaming process comprising extruding a foamable composition at a line speed of 1,000 feet per minute or greater on to a conductor to form a layer of foamed composition on said conductor, said layer having foam cells concentrated towards the center of said layer, whereby said layer has a skin on its interior and exterior surfaces, said skin extending from the surface of said layer into the interior of said layer at least about 5% of the shortest distance between the inner and outer surfaces of said layer, said skin having less than about 50% of the total void content of said layer, and said layer comprising foamed cells wherein 90% of the foamed cells are 50 micrometers in diameter or less, wherein said foamable composition comprises: a) a partially-crystalline melt-processible fluorinated perfluoropolymer, wherein said perfluoropolymer contains less than 50 ppm alkali metal ion and is fluorinated in the melt and contains no greater than 50 —CF2CH2OH, —CONH2, —COF and —COOH endgroups per million carbon atoms, andb) a foam nucleating package comprising i) 91.1±0.5 weight percent boron nitride,ii) 2.5±0.2 weight percent calcium tetraborate, and iii) 6.4±0.2 weight percent of the barium salt of F(CF2)nCH2CH2SO3H, wherein n is 6, 8, 10 or 12, wherein the sum of the weight percents of foam nucleating package components i), ii) and iii) is 100, and wherein said foam nucleating package ranges from 0.1-5 wt % of the combined weight of said perfluoropolymer and said foam nucleating package.