How is recycled material produced in woven products?

At present, domestic woven products are highly competitive and the level of profitability of enterprises is low. In order to reduce production costs, all enterprises are striving to strengthen internal management, deepen their internal potential, and continuously carry out technological innovation and technological transformation to improve economic efficiency. In the production of woven products, if the recycled materials can be used effectively, the cost of raw materials can be reduced and the production cost can be reduced. Especially in the case that the price of polypropylene and polyethylene, the main raw materials of woven products, is greatly improved, the use of recycled materials has obvious effects in improving the economic benefits of enterprises.

Due to the abundant source of polypropylene and relatively low price, polypropylene is widely used as the main raw material for woven products. The application of recycled materials should be determined according to the use and quality requirements of the products. The product quality requirements are low, which can increase the amount of addition; the product quality requirements are high, and the amount of addition can be reduced. This should be explored during the production process. In the production process using recycled materials, the raw materials should be selected correctly. It is necessary to strengthen the monitoring of the production process and continuously adjust the drawing and weaving processes according to the production conditions.

First, the impact of recycled materials on product quality

In general, recycled raw materials are obtained by recycling, washing and regranulating waste plastic woven fabrics. In the process of recycling and reclaiming, due to the aging, pollution, unclean cleaning and high-temperature melting treatment of the waste fabric, the tensile strength and anti-aging property of the recycled material are greatly reduced. The recycled material recovered for the first time has better quality performance; as the number of recycling increases, the quality performance of the recycled material is getting worse. In the production process of woven products, the mixing of recycled materials directly affects the quality of the products. Therefore, when using recycled materials, it is necessary to select raw materials according to the quality requirements of the products and determine the amount of addition. This should be explored and explored in production practice.

Second, the choice of renewable raw materials

Due to the influence of many factors in the production process of recycled materials, the quality indicators vary greatly. Therefore, before using recycled materials, it must be strictly selected according to the performance and quality requirements of the woven products. Conditional companies can also conduct a measurement of the melt index after an apparent test to guide the adjustment of the production process.

For the choice of polypropylene recycled materials, we can use the following methods to test: first observe the surface, the surface waxy, black, no bubbles, good quality; use the teeth to bite the grain, the harder is the polypropylene grain The bite is a good polypropylene pellet, and the softer one is the polyethylene pellet. It is also possible to ignite the pellets on the flame, and after burning off the flame, it can burn by itself. The bottom of the flame color is blue, the top is yellow, and during the combustion process, a large amount of black smoke is emitted, which melts and drops, and emits a smell of oil. It is a polypropylene pellet; in the molten state, the polypropylene pellets which can continuously pull out the filaments are pulled out, and the filaments are short and waxy, and the paraffin-flavored polyethylene pellets after burning.

Third, the pretreatment of recycled materials

The raw materials must be dried and agitated before the molding process. The purpose is to uniformly disperse the materials; pre-plasticize the raw materials to help the molding process. When the recycled material is dry and stirred, the temperature should be controlled at about 100 °C. The regenerated material after stirring and drying should be released in time, and the heat is dissipated in the mixing box to prevent the material from being burned due to the accumulation of material in the dryer. If the humidity of the recycled material is large, it can be placed for several days or longer, and the water is naturally released before use. The stirring and drying time of the recycled material should not be too short, and the temperature should not be too low. Otherwise, it will not function as drying and plasticizing.

Fourth, the process control of recycled materials

After the raw materials are dried and stirred, they enter the barrel of the wire drawing machine and are heated and melted. The heating temperature of the wire drawing machine is controlled in stages, and the temperature of the barrel rises step by step and remains constant to the die. The heating temperature control of the wire drawing machine is also different depending on the properties of the raw material and the type of the flat wire, the linear density and the mixing ratio of the recycled materials. It can usually be determined by combining the type of raw materials, equipment performance and practical experience. The molding temperature of the new polypropylene material is generally controlled at 160 to 250 ° C, and the molding temperature of the recycled material can be appropriately lowered to 150 to 200 ° C according to the amount of the compounding amount.

The molten material is filtered before it is discharged. The purpose of the molten material is to filter the impurities of the material, to stabilize the flow of the material, and to make the product more compact. The wire drawing machine for processing recycled materials generally has a large changeover area and adopts manual network changing. The purpose is to reduce the number of manual network changes and reduce the cost of changing the network. The number of layers of the filter should generally be determined according to the cleanliness and experience of the recycled materials. The mixing amount of the recycled material is large, the impurities are large, the filter should be lean; the mixing amount of the recycled material is small and clean, and the filter can be dense.

After the filtered molten material is discharged through the die, it is immediately cooled. Flat film drawing machines are generally water cooled. The cooling temperature of the recycled material can be controlled between 35 and 45 °C. There are three purposes for cooling: one is to shape the melt; the other is to avoid high temperature oxidation of the material; the third is to prevent the material from crystallizing and to facilitate hot stretching.

The hot drawing and setting temperature of the recycled material are controlled at about 90 ° C and about 100 ° C, and can be appropriately adjusted depending on the type of the flat yarn, the linear density, and the compounding amount of the recycled material. The draw ratio is controlled to 4 to 6 times depending on the amount of the mixed material. There are many recycled materials, the stretching ratio can be smaller; the recycled material is less, and the stretching ratio can be larger.

V. Weaving and bag making

After the flat yarn is wound into a spindle, it is used for weaving the garden loom. At present, most woven companies use the four shuttle looms, which rotate at a speed of 100 to 130 rpm. The performance of the four shuttle garden loom is relatively stable, and it can be used to weave a variety of widths of the cloth, the cloth surface is smooth, smooth, and has a high quality. When the garden loom weaves the recycled flat yarn, it is necessary to adjust the tension of the warp and weft according to the amount of recycled material in the flat yarn. The recycled material is more, the tension is smaller, the recycled material is less, and the tension can be appropriately increased. some. When the recycled flat yarn is woven, it is preferable to use a looms that are actively fed, and the rotation speed of the feed rollers can be appropriately increased. The rotational resistance of the warp beam flat shaft should also be reduced. The tension of the shuttle should be properly adjusted to reduce the resistance of the weft.

In the bag making process, the retraction of the reclaimed material woven fabric is larger than that of the new material woven fabric, and a certain margin is left when cutting. The more the woven bag of the recycled material, the worse the ability to resist aging. When storing, be careful to keep it in a cool, dark, sun-proof place. When using, pay attention to the time limit, and do not place it for too long.