Plastic wire drawing is one of the main processes in the production of plastic woven bags. The wire drawing machine is used as the main production machine. The machine is mixed with various additives such as polypropylene granules, masterbatch, color masterbatch, optical brightener, etc., and then melted, Extruded, cut, shaped, and rewinded to produce flat yarns for plastic woven bags.
Woven bag Plastic wire drawing machine introduction:
Wire drawing machines are also called wire drawing machines and wire drawing machines. They are widely used in industrial applications. They are widely used in machinery manufacturing, hardware processing, petrochemicals, plastics, bamboo and wood products, wires and cables and other industries. Wire drawing machines can be divided into metal wire drawing machines, plastic wire drawing machines, bamboo and wood wire drawing machines, etc. according to their uses.
Plastic wire drawing:
The wire drawing process is common in the plastic process. The wire drawing material is produced by the plastic raw material through the wire drawing process, such as the common PP drawing material and PE drawing material. The drawing material is usually used in the plastic woven industry, such as plastic woven bags, woven bags, and ropes. And other products.
So, what issues should be paid attention to in the drawing process of plastic raw materials?
In the drawing process, the plastic raw materials are first put in a dryer for drying(instead to add desiccant masterbatch), and then the dried raw materials are put into the screw machine, and the screw is forcefully pushed to the head, and then the viscous flow state is extruded The membrane is heated and then stretched under the traction force to increase the longitudinal strength of the flat wire, and finally the drawn wire is wound up.
In short, the plastic raw materials mainly go through the processes of drying（if add desiccant masterbatch then no need to dry）, feeding, extruding, cooling, shearing, stretching, and winding in the drawing process. Therefore, the four most basic points that need to be paid attention to in the drawing process should also be based on These few details are optimized.
Dryness of raw materials for woven bag:
In the drawing and extrusion process, the drying degree of the raw materials is very important. The recycled materials, powder raw materials, and raw materials are not allowed to be over-dried. Once they are over-dried, they will directly affect the luster of the flat yarn, and will be accompanied by peculiar smells, easy melting of the resin, and easy jumps.
On the contrary, if the degree of drying is not enough, it will affect the surface gloss and transparency of the wire drawing product, resulting in broken wires, opaqueness, small pores, and edge curling.So many customers use desiccant masterbatch instead of use dryer machine.
Quality of raw materials:
Before feeding, the quality of the raw materials must be ensured. If the raw materials are mixed with more damp or expired materials, it is easy to block the filter during the processing, causing the fastening to be broken.
Configuration of extruder:
Plastic raw materials need to pay attention to the gap between the screw rod and the barrel in the wire drawing process. Usually the gap between the screw rod and the barrel does not exceed 0.8mm. Once it exceeds 0.8mm, there will be broken wires, threaded edges and poor light and chromaticity. And other phenomena.
Temperature of the extruder:
Extrusion temperature is also an important part of the drawing process. The temperature of the barrel, tee, and die will directly affect the temperature of the flat yarn.
When the extrusion temperature is too high, the melt fluidity is poor, which easily causes uneven film thickness, especially when the die temperature is high, it is easy to cause the film to relax and jump, but when the temperature is too low, poor plasticization, Large extrusion pressure can easily damage the three-way fastening screws.
Regarding the extrusion temperature and the drying and stirring temperature in the wire drawing process, it is determined according to the grades and mechanical properties of the plastic raw materials. Therefore, the extrusion temperature and the drying and stirring temperature of different resins are also different.
Optical Brighteners for wire drawing:
The most common products made of plastic wire drawing in daily life are woven bags. Most of the woven bags are white in appearance. PP woven bags have good recycling performance.
In order to reduce costs and save resources, most manufacturers often use new materials and recycled materials for processing. The recycled materials are generally yellow and old, dull and dull, and the appearance of the woven bags made is not good, usually due to the difference in the recycled materials. It appears black or yellowish.
In order to solve this problem, most manufacturers will add optical brightener to solve the problem of insufficient whiteness.
As for the entire plastic knitting industry, everyone knows that the main purpose of adding optical brighteners to new materials is to reduce yellow and brighten. The main purpose of adding brighteners to recycled materials is to remove the yellow background of recycled materials and solve the problem of dark and blue. Therefore, different products must be selected for new materials and recycled materials in order to achieve the best results.
For new materials (or a small part of recycled materials) for woven bags, our company recommends Optical brightener OB-1 which with blue light. Its appearance is bright yellow-green crystalline powder, high temperature resistance, and low dosage.
For woven bags with all recycled materials and poor materials, the whiteness cannot be improved at all. It is recommended to use Optical Brightener DBH developed by our company for plastic drawing woven bags. This product is specially designed for which the whiteness of recycled materials for woven bags cannot be improved.