Fiber-reinforced strand and method of manufacturing a fiber-reinforced strand

摘要

In a method of manufacturing a fiber-reinforced strand, the fiber-reinforced strand is so manufactured that the cross-section thereof becomes as circular as possible. Particularly a method of causing a reinforced fiber bundle 3 to pass through a resin bath means 7 and, thereafter, twisting the reinforced fiber bundle 3. The resin bath means 7 includes an impregnation region 21 where the reinforced fiber bundle 3 is impregnated with a thermoplastic resin 5 and a twisting region 22 where the reinforced fiber bundle 3 after the resin impregnation can be twisted, and the reinforced fiber bundle 3 after the resin impregnation is twisted in such a manner that a twist pitch P imparted to the reinforced fiber bundle 3 after the resin impregnation within a length L in the twisting region 22 satisfies L/3≧P≧3.15/90×(dtex)1/2.

主权项

1. A method of manufacturing a fiber-reinforced strand by causing a reinforced fiber bundle to pass through a resin bath means storing a molten thermoplastic resin and twisting the reinforced fiber bundle after resin impregnation about a bundle center by a twisting means provided downstream of the resin bath means, wherein
the resin bath means includes an impregnation region where the reinforced fiber bundle is impregnated with the thermoplastic resin and a twisting region where the reinforced fiber bundle after the resin impregnation can be twisted by the twisting means, and the fiber-reinforced strand is produced by twisting the reinforced fiber bundle by the twisting means in such a manner that a twist imparted to the reinforced fiber bundle in the twisting region satisfies Equation (1):L3≥P≥3.1590⁢dtex(1)where
dtex: decitex of reinforced fibers L: length of the twisting region of the resin bath means (mm) P: twist pitch imparted to the reinforced fiber bundle (mm).