Process for producing moldings from foamed polyolefins
First Claim
1. A process for producing a molding from prefoamed polyolefin particles, comprising the steps of:
- a) providing shrunken prefoamed polyolefin particles having a volume of from 30 to 95% of the original volume of the prefoamed polyolefin particles;
b) treating the shrunken particles at a temperature lying at least 20°
C. below the softening temperature of the shrunken particles, in an inert gas atmosphere under a gauge pressure of from 0.2 to 10 bar, for a time sufficient to provide expansion of the shrunken particles upon removal of said gauge pressure;
c) charging the particles into a mold with substantial maintenance of internal pressure of the particles; and
d) foaming the particles.
1 Assignment
0 Petitions
Accused Products
Abstract
A process for producing a molding from prefoamed polyolefin particles, involving: shrinking the prefoamed polyolefin particles to a volume of from 30 to 95% of the prefoamed polyolefin particles original volume to provide shrunken particles; treating the shrunken particles at a temperature lying at least 20° C. below the softening temperature of the shrunken particles, in an inert gas atmosphere under a gauge pressure of from 0.2 to 10 bar, for a time sufficient to provide expansion of the shrunken particles upon removal of the pressure; charging the particles into a mold with substantial maintenance of internal pressure of the particles; and foaming the particles, to provide moldings of very low density useful in applications such as packaging and soft upholstering in motor vehicle interiors.
9 Citations
9 Claims
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1. A process for producing a molding from prefoamed polyolefin particles, comprising the steps of:
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a) providing shrunken prefoamed polyolefin particles having a volume of from 30 to 95% of the original volume of the prefoamed polyolefin particles; b) treating the shrunken particles at a temperature lying at least 20°
C. below the softening temperature of the shrunken particles, in an inert gas atmosphere under a gauge pressure of from 0.2 to 10 bar, for a time sufficient to provide expansion of the shrunken particles upon removal of said gauge pressure;c) charging the particles into a mold with substantial maintenance of internal pressure of the particles; and d) foaming the particles. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification