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Polyester staple fiber manufacturing process

Below is the detailed step-by-step PSF production process:

Wash and Dry – PSF Production Line

Pet flakes will be washed first when tons of pet bales send to the factory.  Most of them have caps, plastic paper,etc.

Extruder and Quenching – PSF Production Line

PET bottle flakes are fed into screw extruder by the meaning of melting, mixing and filtering from hopper after being heated and dried,The melted PET will go through a filter to remove the impurity, like PVC and other materials,The melt goes into a spin beam in which specially-designed distribution piping system guarantees same dwell time and same pressure drop for the melt to reach each spinning position.

The melt becomes a small stream after being extruded from micro-holes of the spinneret and is cooled and solidified by airflow after passing through a low-damping quenching. The melt stream sprayed from spinneret becomes plastic shape monofilament in a very short time and the structure is changed. This change is mainly influenced by the velocity evenness of airflow from quenching. Air temperature and velocity, control of air blowing gap, and airflow steady under high velocity affect the direct factor of yarn quality. Therefore, it requires airflow from quenching with stability, uniformity, and adjustability.

Winder – PSF Production Line

The cooled and solidified filaments are oiled and damped by an oiling device to increase the cohesion of the yarn, to improve the antistatic property of the yarn, to reduce the friction between the yarn and the yarn, and also to reduce the friction between the yarn and equipment, and to improve the after-treatment property of the yarn,After passing through the winder, the yarn from every position is guided by godet roller to the end of take up the unit and is entered into the drawing-off roller, then is fed into Tow Can by sunflower rollers. Six-roll drawing-off and sunflower wheels are driven by a synchronous motor. The engaged depth of two sunflower rollers is adjustable. The drawing-off and sunflower rollers are with the low speed set for yarn string-up and easy operation. The spinning and take-up system is set with the collective communication system.

Can unit – PSF Production Line

Can traversing unit is driven by A.C. motors, which realizes to transporting change of empty can, reciprocating movement of tow can and delivery of laden can. This unit has two kinds of control: manually (except reciprocating movement) and automatic. When tow can reach certain weight by time setting, the programmable-control time counter gives off a signal, and then reciprocating mechanism automatically moves laden can to the center of the unit and delivering mechanism moves laden can out, in meanwhile, to move in empty can for continuous tow collection. Then the tow in a can will be balanced and sent to the after-treatment process.

The second part is finishing line, there are also five steps.

Creel stand – PSF Production Line

The tow creel is arranged for 4 rows, in which, two rows of them are put into using and the other two rows are preparing. The tows from Tow creel are divided into 3 nos. sheets for drawing. The tow cable comes from the creel is guided firstly by Tow guide frame and passed through a dip bath to split tow sheets evenly with certain width and thickness, and ensure more even spin finish in tow sheets, and then start the drawing process.

Stretcher – PSF Production Line

The range uses 2-stage drawing technology. The first drawing stage carries out between the first stretcher and the second stretcher. The temperature of the Draw bath is about 60℃~80℃. The draft ratio of the first drawing stage is completed 80%~85%. The second drawing stage carries in Steam box chest between the second stretcher and the third stretcher. The draft ratio of the second drawing stage is completed 15%-20%.

Stacker and crimper – PSF Production Line

After cooled and oiled, the tow sheets are sent into Tow stacker, 2 or 3 tow sheets are stacked into 1 tow sheet. The tilt angle of stacking rollers is adjustable for achieving stacking process. The width of the tow sheet and the quality of stacking is special important for crimping. After stacking, the tow sheet is sent into Crimper through the Tension control roller and Steam pre-heating box. The tow sheet is crimped through squeezing to assure the good performance of fiber in a later process.

Relax and heating setter – PSF Production Line

After crimping, the tows spread to chain board type conveying of Relaxing dryer. The tows are dried evenly by blowing of forced air and then cooled down below glass temperature.

Baler / Packaging – PSF Production Line

After crimping, the tows spread to chain board type conveying of Relaxing dryer. The tows are dried evenly by blowing of forced air and then cooled down below glass temperature. After dried, the tows are dragged to the upper floor for cutting by a Tension stand, which also guarantees the tows under tension evenness to feed Cutter in the tangential direction of the cutting reel. The tows are cut into fixing length of staple by adopting press cutting. After cutting, the cut fibers enter into baler chamber in gravity or through conveyor for baling, and then the bale is weighting, manual baling and labeling and then sent to the storage by fork lifter.

Is Man-made Fiber ecofriendly and sustainable ?

Economic activities and developments invariably mean interfering with nature.

Therefore, a special responsibility to protect the environment arises from any kind of industrial activity.

A competitive industry is a prerequisite for effective protection of the climate and the environment because only competitive companies can develop novel technologies for efficient resource handling – e.g. to cut greenhouse gas emissions.

These descriptions of connections and backgrounds highlight how man-made fibres and their manufacture contribute to ecological sustainability and help solve environmental problems.

History

After man lost his natural fur in the course of evolution, clothing became as vitally important as food and housing. The first clothes consisted of simple pelts and were worn some 135 000 years ago in the Middle Stone Age. Soon this type of clothes was no longer sufficient, and the man started using fibers from natural plants for clothing purposes.

With the rising quality of life and the growing world population, the consumption and the demand for textiles went up continually. At the same time, the population had to be fed so that a conflict of interests arose, i.e. how to use available agricultural land. Finally, priority was given to food-producing agriculture in order to ensure direct survival – to the detriment of sheep farming and flax cultivation.

Consequently, only continually decreasing areas were available in Europe for the cultivation of renewable resources for the textile industry, so that the demand in Europe could be no longer fully covered with textile raw materials from this continent. Thus raw sheep wool imported from Australia became ever more important. Linen – that had been obtained from flax cultivation – was gradually replaced by cotton which, however, grows only in subtropical to tropical climates.

Most probably, the wish to be independent from transcontinental renewable resources was getting stronger due to military conflicts – which frequently interrupted transatlantic transport routes. Furthermore, requirements to textiles became more sophisticated. As late as in the 19th century, the conflict between agricultural land for food production or for plant growing for clothing purposes was still unsolved. This is understandable when considering that statistically one person would need ca. 1 hectare of fertile land if this person was to resort exclusively to natural products. Given the growing population, it is easy to see why other solutions had to be found to cover the demand for textiles, due to the lack of agricultural areas.

As early as 1665 the Englishman Robert Hooke had the idea to produce artificial fibers from the viscous mass. However, it was a long way with many failures before this idea became reality. For over two centuries the aim defined by Hooke was merely seen as fantastic utopia.

In 1845 Christian Friedrich Schönbein dissolved trinitrocellulose (‘gun cotton’) in alcohol ether, producing collodium. Artificial fibres were produced from this solution for the first time in 1855 by the Swiss Audemars.

Based on these experiments, Count Hilaire de Chardonnet achieved between 1878 and 1884 the breakthrough in the manufacture of the first natural man-made fibre (‘artificial silk’, ‘rayon’) from dissolved dinitrocellulose, which was produced industrially from 1890 – followed by the manufacture of ‘copper rayon’ from a solution of cellulose in copper oxide ammonia for which, however, relatively costly cotton linters (3.5 mm hairs on cotton seed capsules) were needed as raw materials.

Important to this day is the manufacture of viscose fibers from cellulose xanthogenate soluble in sodium hydroxide which became possible in 1885, and the acetylation of cellulose (cellulose triacetate) which was first performed successfully in 1865. From 1919 this material was spun into acetate silk on an industrial scale, by way of partial saponification.

Total independence from the natural raw material cellulose was achieved with synthetic fibers such as e.g. Polyamide 66 (‘Nylon’, 1935), Polyamide 6 (‘Perlon’, 1938), Polyacrylnitril e (1942), Polyester (1941), or Elastan (1958).

After World War II the triumph of man-made fibres was unstoppable. With the start of mass production of successful fibers – such as Polyacryl, Polyamide, Polyester, Elastan, and Viscose – people’s quality and feeling of life improved perceptibly.

That ended the competition between agriculture and clothing industries for limited farmland. Rising fibre production was no longer to the detriment of the population’s food situation.

Raw materials

Today the awareness of the finiteness of fossil raw materials faces especially the energy industry with great challenges. It is urgently imperative for the energy industry to look for alternatives to fossil energy sources because currently some 90 % of petroleum produced go directly – without preceding uses in other material life cycles ‑ into incineration processes (heating and mobility). Here, it is important to significantly enhance the possibilities for using the only external energy source of the ‘system Earth’ – namely the sun – without the ‘detour’ via petroleum or natural gas.

In context with the search for alternative raw materials, the call for renewable resources is getting louder. In the textile sector, too, voices can be heard that advocate an increasing cultivation of natural fibres for this reason. This demand shows that the connection between a stronger use of natural fibres and famines is no longer seen, unlike only 100 years ago. However, first signs that prove the lasting validity of this connection are rising global food prices – because agricultural areas are more and more put to different uses in order to produce raw materials for industry.

Now as in the past, man-made fibers ease the strain on agricultural areas and thus make contributions to sustainability without aggravating the food situation. Only 0.8 % of currently produced volumes of petroleum are needed for the global production of synthetic man-made fibres.

Cellulosic man-made fibres do not compete with food production, either. Only 0.2 % of amounts of wood felled globally are used for the manufacture of cellulosic man-made fibres. Furthermore, the wood used for this purpose comes from sustainably managed plantations or marginal productivity areas that are unsuitable for food crops due to soil conditions, anyway.

Area

In a comparison of areas needed to produce 1 tonne of fibres, 67 ha are required for wool production against only 0.8 ha for viscose fibres – whilst no agricultural area at
all is needed for the production of synthetic fibres.

The sustainability of chemistry – compared with natural fibers – is highlighted even better when looking at the total area used globally for fiber production. 867 000 km2
of grasslands are currently used for wool production (69 % of total fiber production area) and 344 000 km2 (27 %) are used for cotton growing. By comparison, 44 000 km2 (3.5 %) are needed for viscose fiber production while only 400 km2 (0.03 %) are sufficient for the production of synthetic fibers.

Here, sizes of areas are inversely proportionate to yields: With a share of only 3.5 %
in the total area, man-made fibers cover 60 % of the global fiber production. By contrast, 27 % (cotton) of the total area account only for the 38 % share of cotton fibres, and 55 % (wool) of the total area contribute the share of merely 2 % of wool fibre in fibre production worldwide.

The worldwide fibre demand amounts to 68 million tonnes. If man-made fibres were abandoned with a changeover exclusively to wool production, 46 million km2 of grasslands would be needed for this purpose. This corresponds to one-third of the entire land surface of the Earth, with globally available grasslands amounting to only 3.4 million km2. To enable a comparison: The total area of the Federal Republic of Germany is ca. 0.36 million km2; the total area of the Republic of Austria is 0.08 million km2. In theoretically necessary sheep farming, there would be four times as many sheep as humans. Those sheep would emit 160 million tonnes of the climate gas methane, corresponding to 3 700 million tonnes of CO2 equivalent. Global transport burdens the environment with 3.3 million tonnes of CO2 equivalent.

Producing exclusively cotton would not be ecologically viable, either. Currently 25 %
of fertile cultivation areas of good value and suitable for food production are used for cotton growing. If the entire worldwide fibre demand was to be covered with cotton, yields would have to increase by 300 %. Then 75 % of cultivation areas would be taken up by cotton, with only 25 % remaining for food production – resulting in global famines. In practice, such a dramatic increase in cotton areas would not even be possible, because cotton can be cultivated only in certain climatic conditions. Therefore, improved yields can be achieved only with artificial irrigation and high inputs of fertilisers and pesticides. Already now, some 10 % of globally used insecticides and one-fifth of all pesticides are sprayed in conventional cotton cultivation.

Water consumption

Crop cultivation requires not only agricultural areas but also water. It is a well-known fact that water resources worldwide are limited and precious. For example, in cotton growing some 25 000 m3 liters of water are needed to produce 1 tonne of cotton fibers – which is doubtful in ecological terms. This is over 70 times the water quantity needed for viscose fiber production and over 6 000 times more than what is required in polyester fiber production. Thus man-made fibres make important contributions to preserving vital water resources.

Without man-made fibers, there would be neither enough agricultural areas for food production nor sufficient water resources for humankind.

CO2-balance

Compared with natural fibres, man-made fibres offer the extra advantage that they can be manufactured wherever there are markets with a demand for them. Grasslands and arable areas cannot be created just anywhere – unlike production plants for man-made fibres.

Transporting textiles across the globe makes little sense ecologically, even less so if they are made of man-made fibres. But also T-shirts made of biologically grown cotton may have flown half across the globe. For example, an item of clothing made in China is transported over a distance of ca. 19 000 km to the final consumer in Europe. If transported by ship, some 0.4 kg of CO2 is emitted per kg of textile.

In air transport, the eco-balance deteriorates by ca. 10 kg of CO2. Assuming that textile production exclusively in Europe would involve transport distances of ca. 2 000 km, in European rail transport ca. 0.04 kg and in air transport ca. 1 kg of CO2 would be calculated in an eco-balance for the transport of textiles. Considering that ca. 90 % of textiles offered in Germany are imported, the ecological benefits of manufacturing man-made fibres and textiles close to their consumers are obvious

Recycling

Man-made fibres are ecologically valuable also after their use as products. Whilst cellulosic man-made fibres are biodegradable, synthetic fibres can be reused in the recycling process, via their monomers. Furthermore, many man-made fibres consist of recycled raw materials in the first place. For example, annually some 40 % of old PET bottles in Europe are processed into fibres. This reduces rubbish piles by 10 million PET bottles per day, saving 200 000 tonnes of primary raw materials.

Unlike natural fibers, the energy fraction in man-made fibers can be recovered and used for heating purposes in the form of long-distance heating, saving valuable primary energy.

“Eco” or not

The growing trend toward and the rising demand for environmentally friendly textiles, manufactured in socially acceptable conditions, leads to a proliferation of eco-labels and eco-collections. However, so far designations such as “natural”, “bio” or “eco” are not protected in respect of clothing. The sweeping judgment “nature is better than chemistry” is unjustified, because the overall eco-balance of man-made fibers is more favorable than that of cotton. Besides energy and resource consumption, also factors such as machine deployment, fertilizers, and finishing and transport costs must be taken into account.

Man-made fibres are used in several technical applications and also help solve with environmental problems.

Light weight by Man-made fibres

Man-made fibres are indispensable raw materials for light weight constructions. Synthetic fibers are precursors for carbon fibers that are processed into modern composite materials, for use as metal substitutes. With the use of composite materials in aircraft and automotive industry high reduction in weight and significant decrease of fuel consumption can be achieved

Insulating materials save energy

Up to 80 million tonnes of CO2 emissions can be avoided annually with insulating materials. Man-made fibers are processed into nonwovens – for use in buildings as insulating and sealing materials in facades, floors, and windows or as roofing sheets. Energy savings achieved with innovative products based on man-made fibres are higher than the energy input needed in the production of these products and fibres

Strong presence in environmental protection

At the workplace, in production, in exhaust gas and air purification. Almost always in the background, unseen and unnoticed – man-made fibres make active contributions to clean water and air. As nonwovens, man-made fibres filter liquids, collect solids and e. g. purify waste air from power plants by removing pollutant particles. Only man-made fibres can resist such a wide range of thermal and chemical strains.

Man-made fibres are the solution

Humans and the environment must adapt to changing conditions that come with climate change. Man-made fibres are the solution. As nonwovens, wovens and nets they make foundation materials for roads on less stable ground and also help reinforce ways, dams and heaps

 

Source from: Industrievereinigung Chemiefaser e.V.

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