Method for producing dacron FDY (Fully Drawn Yarn) filaments in large scale by utilizing recycled PET (Poly Ethylene Terephthalate) bottle chips

Abstract

The invention provides a method for producing dacron FDY (Fully Drawn Yarn) filaments in large scale by utilizing recycled PET (Poly Ethylene Terephthalate) bottle chips. The method comprises the following steps: crushing recycled PET bottles into chips; cleaning and then drying; feeding the chips into a crystallizing bed so as to crystallize, and then drying; pouring the dried bottle chips into a screw extruder for performing fusion extrusion; causing the filtered flux to enter into a homogenizing kettle and performing condensation polymerization for 1.4-1.5 hours, thereby homogenizing the flux in the homogenizing kettle; causing the homogenized flux to enter into a spinning box; and spinning according to a high-speed spinning technology, thereby obtaining the dacron FDY filaments. A homogenizing step is added in the producing method, so that the problems of big viscosity fluctuation and inferior stability of the flux of the PET bottle chips are solved, and the continuous and large-scale production of the FDY filament products by taking the recycled PET bottle chips as raw materials is realized.

Description

technical field [0001] The invention provides a method for large-scale production of polyester FDY filaments, in particular a method for large-scale production of polyester FDY filaments from recycled PET bottle flakes. Background technique [0002] The traditional method of producing polyester FDY (abbreviation for fully drawn yarn, ie fully drawn yarn) filaments uses raw polyester chips as raw materials. The raw material is characterized by high purity, stable viscosity and low water content. Its production process is short, and the specific process is drying-screw melt extrusion-first-stage filtration-spinning. The disadvantage is high cost and large consumption of petroleum resources. For this reason, people are actively looking for ways to produce polyester FDY filaments with other raw materials such as PET (polyester) bottle flakes. However, due to the large change in intrinsic viscosity, unstable quality, high water content, high impurity content and low bulk densit...

AI Technical Summary

Problems solved by technology

[0005] This method of producing polyester FDY 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 operating 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 for spinning; Class filter for filtering, divided into coarse filter and fine filter, the coarse filter has fewer meshes to reduce the filtration pressure, and the fine filter has more meshes to ensure the filtering quality and good filtering effect