Preparation method for polyvinyl alcohol coarse denier monofilaments

Abstract

The invention discloses a preparation method for polyvinyl alcohol coarse denier monofilament fibers. The high-strength high-modulus coarse denier polyvinyl alcohol monofilament fibers are prepared by a solid-phase alcoholysis spinning method. The preparation method is characterized in that: polyvinyl alcohol with a low alcoholysis degree under the plasticization of a small amount of water is spun to prepare the coarse denier fibers at a relatively low temperature, and the extraction problem caused by a plasticizer and the problem that the coarse denier (more than or equal to 1,000 D) fibers cannot be produced by a wet spinning method are avoided; the small amount of water is added to make the polyvinyl alcohol in a molten state, the fibers are extruded by a single screw, metered by a metering pump and extruded out of a spinning jet; a small amount of moisture existing can be removed by heating; and the fibers are subjected to drying, multi-level stretching (10 to 16 times) and high-temperature tension and heat shaping to form the high-strength high-modulus fibers. The preparation method makes up defects of the prior art and products sold in the market and meets the requirements on plasticizing, anti-cracking and the like of concrete in building projects.

Description

technical field [0001] The invention relates to a method for preparing coarse-denier and irregular-shaped monofilaments used in civil engineering, in particular to a method for preparing polyvinyl alcohol (PVA) coarse-denier monofilament fibers. Background technique [0002] Existing coarse denier chemical fiber monofilaments used in the field of civil engineering concrete, its technology and the products formed include polypropylene (PP) monofilaments, jelly spinning coarse denier fibers and polyvinyl alcohol (PVA) fibers sold on the market, wherein ( 1) Polypropylene (PP) monofilament is found in "a non-equal diameter polypropylene monofilament" disclosed in the Chinese utility model patent with the authorized announcement number CN2606750Y. The defect is that the hydrophobicity of polypropylene itself cannot be mixed with cement matrix. The material forms a relatively firm grip; (2) The polyvinyl alcohol (PVA) fibers sold on the market, due to the wet forming process, the...

AI Technical Summary

Problems solved by technology

[0002] Existing coarse denier chemical fiber monofilaments used in the field of civil engineering concrete, its technology and the products formed include polypropylene (PP) monofilaments, jelly spinning coarse denier fibers and polyvinyl alcohol (PVA) fibers sold on the market, wherein ( 1) Polypropylene (PP) monofilament is found in "a non-equal diameter polypropylene monofilament" disclosed in the Chinese utility model patent with the authorized announcement number CN2606750Y. The defect is that the hydrophobicity of polypropylene itself cannot be mixed with cement matrix. The material forms a relatively firm grip; (2) The polyvinyl alcohol (PVA) fibers sold on the market, due to the wet forming process, the fiber size cannot be greater than 20D, the fibers are thin, and the dispersion and reinforcement effect of the fibers are not good. Good; (3) jelly-spun coarse denier fiber is detailed in "a kind of polyvinyl alcohol monofilament of non-equal diameter shape" in the authorized announcement number CN201033811 of the Chinese Utility Model Patent Disclosure, which has a long process flow and high production cost, etc. Disadvantages; (4) alcoholysis direct spinning, (Ye Guangdou, "Synthetic Fiber Industry" 1998, third issue), due to the wet process route, there is a skin-core structure, and coarse denier fibers cannot be prepared