| 摘要 |
PROBLEM TO BE SOLVED: To provide reinforcing composite fiber for cement, which contains polyolefin-based fiber such as polypropylene fiber or polymethylpentene fiber and can be dispersed well in a cement slurry and, when the reinforcing-fiber-containing cement slurry is formed into a cement formed body by using a papermaking or extrusion process, hardly floats up on the surface of the cement slurry. SOLUTION: This composite fiber using a polyacetal-based resin and a polyolefin-based resin as components, has two types, that is, core-sheath type composite fiber and division type composite fiber. The core-sheath type composite fiber in which the polyacetal-based resin is used as a sheath component and the polyolefin-based resin is used as a core component, can be dispersed well in a cement slurry, because of hydrophilicity and high specific gravity of the polyacetal-based resin. The division type composite fiber has a structure such that each of the both components continuously exists in a part of the surface of the composite fiber, and in the division type composite fiber, when divided in a cement slurry, since polyacetal-based fiber and polyolefin-based fiber coexist in a mixed state in the cement slurry, the polyolefin-based fiber can be dispersed well in the cement slurry because of good dispersibility of the polyacetal-based fiber, wherein mixing of a filler into the polyolefin-based fiber in order to enhance its specific gravity and hydrophilicity, is more effective in well- dispersing the polyolefin-based fiber in the cement slurry.
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