Reinforcing short fibers having excellent fibrillation property

摘要

PROBLEM TO BE SOLVED: To provide a staple fiber for reinforcement having excellent loosening property and high cement-reinforcing effect, and quickly loosened and uniformly dispersed without carrying out mechanical agitation for a long period even in an alkaline medium developed e.g. by adding a kneading water to a hydraulic material such as cement.;SOLUTION: The reinforcing staple fiber having excellent loosening property is a bundled staple fiber produced by separably integrating a plurality of polyvinyl alcohol staple fibers with a bundling agent. The aspect ratio of the staple fiber is 100-1,000 and the bundling agent is a (meth)acrylic acid copolymer having a number-average molecular weight of 1,000-100,000 and containing 20-40 mol% constitution unit expressed by formula 1, 10-30 mol% constitution unit expressed by formula 2 and 45-60 mol% (the total of the components is 100 mol%) constitution unit expressed by formula 3.;COPYRIGHT: (C)2005,JPO&NCIPI