Polyester bottles have the advantages of light weight, not easy to break, corrosion resistance, etc., and are widely used in food packaging. But waste polyester bottles are difficult to degrade, and incineration will produce harmful gases and pollute the environment. Recycled polyester staple fiber has low strength and many defects. There are super-long fibers, which can be compensated by spinning, and the unit consumption is low. Recycled polyester staple fiber has the characteristics of low raw material cost, high profit and environmental protection.
The production of recycled polyester is divided into front spinning and back spinning.
Before spinning includes: 1. Material selection
We know that the raw materials used in recycled chemical fiber are mainly bottle tablets, foam X-ray films, oil pot materials, etc. Bottle tablets are divided in color: white tablets, blue tablets, blue and white tablets, green tablets, coffee tablets, variegated tablets. From the performance points: cold water tablets, hot water tablets. From cleanliness: clean film and wool film. Blue and white films are generally used in the production of recycled chemical fiber.
Transparent polyester bottle flakes can be used to produce white polyester staple fiber by adding fluorescent whitening agent OB-1 with a mass fraction of 0.02-1% The toner is added 2 hours before the drum is dried and discharged, and the vacuum is stopped. Due to the thin and fluffy flakes and large intrinsic viscosity, when entering the screw extruder to melt from solid to liquid, its volume decreases rapidly, resulting in unstable spinning pressure. The appropriate proportion of foam can be added to mix to solve .
The purpose of drying is to remove moisture, improve the crystallinity of the raw materials, prevent the formation of bubbles and generate wool or broken ends, and reduce the hydrolysis of polyester. Use vacuum drum desiccant drying, drying temperature 110-115 degrees. The vacuum degree is lower than -0.09Mpa, and it is generally dried for 8-12 hours.
The spinning temperature is high, the melt viscosity is low, the fluidity is good, the floating yarn and the end are few, the spinning is smooth, but the temperature is too high, which leads to the thermal degradation of the melt. It causes spun yarn and many yarns. The spinning temperature is too low, the melt viscosity is too high, and the fluidity is poor. It is easy to cause slurry leakage and produce hard yarns. After stretching, it is easy to produce wool yarns and broken yarns.
5. Ring blow cooling
The production of polyester staple fiber usually uses ring blow cooling tow.
The oiling rate is low, the fiber is easy to generate static electricity, the oiling is too much, and the roller is easy to stick.
After spinning process includes
The bus density of the bundle is mainly determined by the drafting capacity of the drafting machine and the width of the crimping wheel. The width of the wire entering the crimping machine must match the width of the crimping wheel.
The production of recycled polyester fiber adopts two draws. The first draw uses oil-water bath as the heating medium, which is conducive to the stability of the drawing point, and the second draw uses superheated steam as the heating medium, which is beneficial to quickly increase the temperature of the tow.
Fiber crimping can increase the cohesion between fibers and improve spinnability.
4. Relaxation heat setting
Relaxing heat setting can eliminate internal stress and reduce fiber shrinkage and moisture regain.
5. Cut off
The length of the fiber is cut according to the needs of the customer, and the tension device of the cutting machine is adjusted to make the tow tension uniform and moderate to reduce the length deviation.
This is the entire production process of recycled polyester fiber. The addition of fluorescent whitening agent is added in the batching process. The varieties of fluorescent whitening agent are mainly fluorescent whitening agent OB-1. The appearance of this fluorescent whitening agent yellow-green crystalline powder is especially suitable for polyester whitening.
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Talk about the whitening principle of fluorescent whitening agent
Post time: May-13-2020