Method for producing industrial polyester filament by recycled PET (Polyethylene Terephthalate) bottle chips on scale

Abstract

The invention provides a method for producing industrial polyester filament by recycled PET (Polyethylene Terephthalate) bottle chips on a scale. The method comprises the steps of crushing the recycled PET bottles into chips, washing and drying, sending into a crystallization bed body for crystallization, forming crystallization layers on the surfaces of the bottle chips, sending the crystallizedbottle chips into a drying tower which is provided with a pair of spiral agitators, leading the dried bottle chips to enter a screw extruder for melting and extrusion, sending the obtained melt into a two-stage filtration device consisting of a coarse filter, a fine filter and a pressure pump between the coarse filter and the fine filter for filtration, leading the melt which is filtrated by two stages to enter a liquid phase tackifying kettle, conducting polycondensation reaction in the liquid phase tackifying kettle, leading the melt after being subjected to liquid phase tackifying to entera spinning box, and spinning by adopting a high-speed spinning process, thus obtaining the industrial polyester filament. In the method for producing the industrial polyester filament, the liquid phase tackifying step is added in the production process, so that the problems of low viscosity and poor stability of the PET bottle chip melts are solved.

Description

technical field [0001] The invention provides a method for large-scale production of polyester industrial filaments, in particular a method for large-scale production of polyester industrial filaments from recycled PET bottle flakes. Background technique [0002] The traditional method of producing polyester industrial filaments uses virgin polyester chips as raw material. The raw material is characterized by high purity, stable viscosity and low water content. Due to the high strength of industrial yarn, the strength is generally 7.00-8.20cN / dtex, so the viscosity of the melt is required to be higher than that of the polyester fiber for textile production, which should be 0.82-0.910±0.001dl / g, while the viscosity of virgin polyester chips is generally 0.6dl / g, so it is necessary to increase the viscosity of the raw polyester chips to increase the molecular weight of the polyester, that is, to carry out the polycondensation reaction. Since it is a solid-phase polycondensati...

AI Technical Summary

Problems solved by technology

[0005] This method of producing polyester industrial filaments adopts a filling drying method to ensure uniform drying. Compared with drum drying, it solves the problem of inconsistent water content between drums during large-scale production. The process is less and the operation cost is low; a spiral agitator is installed in the drying tower, which solves the problem of "bridging" in the drying process of recycled PET bottle flakes due to their small unit volume and irregular shape. The cyclone separation method separates the fine powder from the bottle flakes, which solves the problem that the melt is degraded due to the early melting of the fine powder in the bottle flakes, resulting in a decrease in melt viscosity or instability, which is unfavorable to spinning; Class filter for filtering, divided into coarse filter and fine filter, the coarse filter has fewer meshes, which reduces the filtration pressure, and the fine filter has more meshes, which ensures the filtering quality and good filtering effect