tow pre-pregs

This technology is available from Temarex Corporation.

TOW PRE-PREGS, THERMOPLASTIC COATED

Advantage: These two (2) pre-preg inventions overcome the problem encountered in the preparation of fiber reinforced thermoplastic composites.The problem identified is that it is difficult to obtain good wetting of the reinforcing fibers or filaments, and consequently it is difficult to obtain composites in which air bubbles are absent at the interfaces between resin and reinforcing fiber.

Tow-pregs prepared according to the present invention are nearly as flexible and have nearly as good a hand as the uncoated fiber.This is in contrast to tow-pregs prepared according to methods presently known in the art, which tend to be stiff.At the same time, the coatings in tow-pregs of this invention are continuous and therefore fully compatible with the matrix polymer of the end use composite into which the tow-preg (or pre-preg) herein is incorporated.The reduced stiffness of pre-pregs herein, compared to those of the prior art, greatly facilitates preparation of the end composites.Tow-pregs prepared according to the present inventions are sufficiently flexible to be suitable for weaving applications.

Title:METHOD OF DEPOSITING AND FUSING POLYMER PARTICLES ONTO MOISTENED CONTINUOUS FILAMENTS

Inventor(s):J. Throne

Disclosure 131 U.S. Patent 5,364,657

Process for making a tow pre-preg comprising long continuous fibers coated with a thermoplastic polymer.

A continuously moving spread tow of long continuous fibers, preferably carbon or glass, is humidified in an atmosphere of essentially 100% relative humidity and coated with particles of a thermoplastic polymer.A polymer particle-laden air stream contacts the moistened continuously moving tow, depositing polymer particles on the fibers.

The fiber diameter is about 5-50 microns and the mean particle diameter is about 0.1-40 microns.The fibers with thermoplastic particles clinging thereto are continuously heated to a temperature sufficient to cause fusion of the thermoplastic polymer.This results in long continuous fibers coated with the thermoplastic polymer.The resulting tow-preg, or tow of coated fibers, is useful in the preparation of structural composites in which the fibers service reinforcing fibers.

The thermoplastic coating polymer is a high performance polymer, such as PEEK, UHMWPE, thermoplastic polyimide (TPI) and polybenzimidazole (PBI), where high performance and the structural composite is desired.Other high performance thermoplastics are known and may be used as coating materials. Coating polymer constitutes from about 10 to 80 percent and fiber conversely from about 90 to 20 percent by weight of a coated fiber tow product or tow-preg.

This technology is ideally suitable for non-aerospace applications such as model kit airplanes, (high performance) bicycle and motor cycle frames, sports equipment, home and institutional athletic\rehabilitation work out equipment (i.e. step machine), ultra light wheel chairs and the like.Another application is for structural repair and strengthening of damaged prestressed bridge\pier columns, or reinforcement\retrofit of undamaged columns located in seismic regions (advantage - avoid liquid treatments on a vertical structure).Of course, aerospace and high speed civil transport vehicles remain viable applications.

Title:METHOD OF DEPOSITING AND FUSING CHARGED POLYMER PARTICLES ON CONTINUOUS FILAMENTS

Inventor(s):J. Throne, A. Ogden

Disclosure 127 U.S. Patent 5,370,911

Process for making a tow pre-preg (or tow-preg) comprising long continuous fibers coated with a thermoplastic polymer. A spread tow of long continuous fibers, preferably carbon or glass, is grounded and coated with electrostatically charged particles.

The process of depositing and fusing polymer particles onto continuous filaments is similar to that described in Disclosure #131, except in this process, the filament is not moistened at time of depositing and fusing.

The mean fiber diameter, mean particle diameter, and the ratio of mean particle size are the same as described in Disclosure #131. Likewise, the thermoplastic coating polymers are the same as described in Disclosure #131.Polymer coating weights may vary from about 10% to about 80% of the total tow-preg weight.