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US 4,731,215 AGranted
Process for forming non-woven webs from highly oriented melt blown fibers
AssigneeBiax-Fiberfilm Corporation
InventorEckhard C. A. Schwarz
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Abstract
There is disclosed a process and apparatus for melt blowing at an initial velocity of from 500 to 1000 feet per second a molten thermoplastic condensation polymer at a temperature less than 50.degree. C. above the melting point thereof to form fibers of high molecular orientation, and collecting the fibers to form a non-woven web. In one aspect of the present invention, the fibers are collected on a rotating mandrel and heat treated during collection or subsequent to collection.
Claims6
A process for producing a tubular sleeve of non-woven fibers, which comprises:
- (a) heating a thermoplastic condensation polymer selected from the group consisting of polyethylene terephthalate and nylon 6,6 to a molten state to a temperature sufficient to attain an apparent melt viscosity of less than 50 poise;
- (b) spinning by melt blowing said molten thermoplastic condensation polymer in the presence of a first gaseous medium heated to melt blowing conditions to form oriented, heat shrinkable, melt blown fibers, said melt blown fibers exhibiting a shrinkage of at least about 19%;
- (c) collecting said melt blown fibers on a rotating mandrel to form a loose tubular sleeve of said oriented melt blown fibers;
- (d) contacting said tubular sleeve with a second gaseous medium heated to a temperature of from 70.degree. to 265.degree. C. to thereby shrink and entangle said melt blown fibers and form a rigid cartridge having a density of at least 0.1 gram/cc;
- and
- (e) removing said cartridge from said rotating mandrel.
3 more elements
Dependencies are inferred from the claim text.