Process for extruding thermoplastic materials using low pressure

Details Process for extruding thermoplastic materials using low pressure Process for extruding thermoplastic materials using low pressure

1989-11-30

1991-07-23

Lorin, Hubert C.

Plastic and nonmetallic article shaping or treating: processes

Pore forming in situ

By gas forming or expanding

26421123, B29C 6722

Patent

active

050341715

ABSTRACT:
A process for producing microcellular foamed articles wherein a low pressure compressible, inert gas such as nitrogen is used as a foaming agent. The process comprises introducing a thermoplastic material into an inlet of an extruder having a length to diameter ratio of at least 30:1, said extruder comprising a screw having at least one stage; heating the thermoplastic material in a melt zone to a temperature sufficient to melt or soften the thermoplastic material to form a melted thermoplastic material; injecting an insoluble compressible, inert gas into the melted thermoplastic material at a position approximately 1 to 2 screw diameters downstream of the melt zone; mixing the molten thermoplastic material and the inert, compressible gas to form a homogeneous dispersion of insoluble bubbles within the material; reducing the pressure of the molten thermoplastic material causing the homogeneously dispersed bubbles to expand within the melted thermoplastic material to form a foamed article and cooling the foamed article to a temperature below the melting or softening point of the foamed article.

REFERENCES:
patent: 3444283 (1969-05-01), Carlson, Jr.
patent: 3806569 (1974-04-01), Gallard et al.
patent: 3814779 (1974-06-01), Wiley
patent: 3843757 (1974-10-01), Ehrenfreund et al.
patent: 4185060 (1980-01-01), Ladney, Jr.
patent: 4390332 (1983-06-01), Hendry
patent: 4393017 (1983-07-01), Kim et al.
patent: 4409164 (1983-10-01), Brasz et al.
patent: 4409165 (1983-10-01), Kim
patent: 4473665 (1984-09-01), Martini-Vvedensky et al.
patent: 4913864 (1990-04-01), Soga et al.

Affiliated with

Also associated with

Rating

Process for extruding thermoplastic materials using low pressure does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Process for extruding thermoplastic materials using low pressure, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for extruding thermoplastic materials using low pressure will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-431253