关键词: 聚氯乙烯纤维, 熔融纺丝, 力学性能, 耐腐蚀性能, 牵伸工艺

Abstract: Polyvinyl chloride is a non-toxic, odorless, and widely used thermoplastic material. It has advantages such as good flame retardancy, acid and alkali resistance, low price, good physical properties, and electrical insulation. It is currently one of the most widely used plastics. However, due to its poor stability to light and heat, it can decompose and produce hydrogen chloride when exposed to sunlight above 100 ℃ or for a long time, causing discoloration and rapid decline in physical and mechanical properties. When applying, it is necessary to add plasticizers, heat stabilizers, and other additives to improve the stability of PVC materials to light and heat. The traditional methods for PVC spinning and forming are wet spinning and dry spinning, but both methods require PVC resin to swell in acetone. However, acetone itself is toxic, and solvent recovery is harmful to the environment. The melt spinning method lags behind other technologies due to the poor heat resistance of PVC and its thermal decomposition and carbonization at high temperatures.
This article used heat stabilizers and plasticizers to modify PVC resin to make it resistant to high temperatures and enable smooth melt spinning. The melt spinning process of PVC fibers was studied. The melt flow index instrument was used to test the melting temperature of PVC granules to preliminarily determine the optimal spinning temperature. The effects of different spinning temperatures and drafting ratios on the structure and properties of PVC fibers were studied. And research on the breaking strength, elongation at break, crystallinity, surface and cross-sectional morphology, as well as acid and alkali corrosion resistance and flame retardancy of the fibers were conducted. Through comparative experiments, it is found that the optimal comprehensive mechanical properties of PVC fibers are obtained when the screw temperature is 160 ℃ and the spinneret temperature is 190 ℃. When the drawing ratio is 4, the breaking strength and orientation of PVC fibers are the highest. The best spinning parameters obtained from the experiment are as follows: the spinneret is 1 cm away from the water bath, the screw temperature is 160 ℃, the spinneret temperature is 190 ℃, the hot water bath temperature is 60 ℃, the metering pump pressure is 2 MPa, and the drafting ratio is 4. Under such conditions, the PVC fibers prepared have the best performance, and their breaking strength, breaking elongation, and Linear density are 1.16 cN/dtex, 32.1%, and 12 tex, respectively; PVC fibers have excellent mechanical properties, good flame retardancy, and excellent resistance to acid and alkali corrosion. They have minimal loss of quality and strength in acid and alkali solutions, especially in acidic solutions. 
The use of melt spinning technology to prepare PVC fibers has the advantages of simple process and low price. And the PVC fibers obtained through melt spinning have excellent properties and can be used to prepare corrosion-resistant and flame-retardant fabrics.

Key words: PVC fiber, melt spinning, mechanical properties, corrosion resistance, drafting process