Method of depositing and fusing charged polymer particles on continuous filaments

  • US 5,370,911 A
  • Filed: 04/20/1990
  • Issued: 12/06/1994
  • Est. Priority Date: 04/20/1990
  • Status: Expired due to Term
First Claim
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1. A process for coating a fiber tow with a thermoplastic resin polymer which comprises:

  • (a) pneumatically spreading a fiber tow of long continuous fibers and electrically grounding said fibers;

    (b) forming a particle-laden air stream by introducing uncharged thermoplastic resin polymer particles from a fluidized bed into a flowing air stream which is at a velocity in excess of the settling velocity of said particles;

    (c) electrostatically charging the particles in said particle-laden air stream;

    (d) depositing the charged polymer particles from said air stream on to the spread tow of long continuous fibers formed in step (a), wherein said charged particles have a mean particle size in the range of about 0.1 to about 40 microns, said fibers are dry, uncoated and uncharged and of essentially uniform diameter in the range of about 5 to about 50 microns and the ratio of mean particle size to fiber diameter is in the range of about 0.1 to about 10;

    (e) heating the fibers with adhering particles to a temperature sufficiently high to fuse said particles of thermoplastic polymer and thereby form a coating of said thermoplastic polymer on said fibers; and

    (f) winding up the coated fibers.

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