US 6,132,657 A · Process for producing polymeric materials

Abstract

An improved process for producing a consolidated polymeric monolith from an assembly of thermoplastic polymer fibers. The assembly is placed under pressure to fill a majority of the voids thereof by mechanical deformation of the fibers, and heated to a temperature too low to melt the fibers at the deformation pressure but sufficiently high to at least partly melt the fibers at a lower transition pressure. While maintaining the assembly at this temperature, the pressure is reduced to the transition pressure long enough for partial melting of the fibers to fill the rest of the voids, and then is increased to a consolidation pressure at least as high as the deformation pressure. The assembly is cooled slowly to ambient temperature at the consolidation pressure.

Claims17

Dependent claims

A process for the production of a consolidated polymeric monolith from thermoplastic polymer fibers, comprising the steps of:

(a) forming an assembly of thermoplastic polymer fibers;
(b) applying a pressure to said assembly sufficient to deform the fibers to substantially fill a majority of voids in said assembly, said assembly having a melting temperature at said deformation pressure;
(c) heating said assembly to a temperature below said melting temperature but at which said assembly would at least partly melt at a transition pressure lower than said deformation pressure;
and
(d) subsequently reducing said applied pressure to said transition pressure while maintaining said assembly at said temperature for a time sufficient for said assembly to at least partly melt, thereby substantially filling a remainder of said voids.

2 more elements

Dependencies are inferred from the claim text.

Process for producing polymeric materials

Life of this patent

Process for producing polymeric materials

Life of this patent

Abstract

Claims17