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Discussion on the Development Trend of Spunbonded Technology

2022-09-15  41

Spunbonded method is a comprehensive technology involving many disciplines. Spunbonded technology is developing rapidly and has formed several distinctive production modes. We should strengthen development, innovate constantly, and form our own proprietary technology and intellectual property rights, which is the fundamental way for enterprises to remain invincible.

1 Large plate narrow width

Since the products produced in the large plate mode have uniform surface, they are suitable for medical and health products. Since most of these products have colors, because the output of narrow production lines is low, several narrow production lines are installed, and each line produces one color, so as to minimize the transition color products and improve economic efficiency.

2 Small board width

The vertical and horizontal strength difference of the small board mode is small. The products are suitable for waterproof base cloth and packaging materials. Most of these products are colorless. At the same time, the processing cost of the large board spinneret increases exponentially. The production line with a width of 5. lm has been put into production. At present, the domestic high-yield extruders have been industrialized, and the manufacturing technology of wide hot rolling mills has been mature. Production lines with a width of 6.4m and an annual output of tens of thousands of tons of 9.6m may also be manufactured. It is calculated that the unit power consumption of the production line with the output of 20000 t/a single die of 6.4 m in width reaches 450 Kwh; The width of double die head in large plate mode is 3.2m, and the output is 15000 t/a, and the unit power consumption reaches 434Kwh.

With the rapid development of nonwovens industry in recent years, the number of spunbonded lines has expanded rapidly, and improving the production capacity of single machine equipment has become the focus. Although there are some difficulties in the design and manufacturing of wide and high-speed production lines, high-yield production lines play a positive role in reducing the processing costs and large-scale management of the entire industry, and enable production enterprises to bring considerable economic benefits in the market competition. For example, in the 1970s, the output of small chemical fertilizer was 3000 t/a, and later it developed into a large ammonia plant of 300 kt/a; The output of the original small paper mill is thousands of tons, and 400000 t/a paper machines have appeared in recent years. This is the trend of social development and the inevitable result of market competition and technological progress.

3 Spunbonded and melt blown composite

Spunbonded and melt blown composite (SMS for short) nonwovens are suitable for all applications from filter materials to sanitary cladding materials. This method makes full use of the advantages of the two to overcome their shortcomings. The nonwovens produced have the dual characteristics of fine denier of melt blown fiber, good filterability, soft handle, and high strength of spunbonded continuous filament.

4 Polyester tube drafting

As the spinning speed of polyester fiber is required to be high, the air for spinning and drawing of polyester fiber needs higher pressure and more flow, and the power consumption of drafting takes a large proportion of the total power consumption. As the air consumption of tube drafting is less, most polyester fiber spinning and drawing uses tube drafting devices from the perspective of energy conservation.

5 Orange petal fiber spunlace

The superfine fiber nonwovens made of spunbonded orange petal fiber filament through spunlace are used for wiping cloth, medical and sanitary products and the base cloth of high-grade synthetic leather due to their good performance. For example, the Evolon of Kedebao Company belongs to this product. The fiber size of this product is between 0.05 and 0.13dtex. Such superfine fibers cannot be directly spun from spinneret. They are split from orange petal fibers through the water pricking process. In the past, the superfine short fibers in the carding fiber web were obtained by dissolving a component from island or orange petal fibers.

When orange short fiber is combed and spunlaced, it is easy to cause fiber cracking and knot in the carding process when the adhesion is low. Although the carding performance of the fiber can be improved when the adhesion is high, the fiber is not easy to split in the spunlaced process. The requirements of carding and spunlacing on the adhesion of orange short fiber are contradictory.

Spunlaced products have good flatness and uniform product density, and will not damage fibers like the needle punching process. Spunlaced nonwovens have much higher strength than combed nonwovens. The combination of spunbonded fiber and spunlaced fiber is used to produce superfine fiber nonwovens. It is a continuous production process from polymer chips to final products. When the spunbonded fiber mesh made of lightly bonded orange petal fiber passes through the spunlaced fiber, it is not only used to wind the fiber, but also used to split the orange petal fiber. The fiber mesh consolidation and fiber splitting are completed at one time, which greatly reduces the processing cost of the product, avoids the environmental protection problems caused by the use of chemicals, and also solves the difficulty of processing superfine fibers on the carding machine.

Split microfiber, also known as orange petal fiber or split fiber, gets its name because its cross section is like a cross cut orange. It is made by ejecting two kinds of fibrous polymers with different properties from the same spinning hole using the same spinning component. Due to differences in modulus, elongation and shrinkage, the two kinds of fibrous polymers are easy to separate at the interface under the action of external forces. The surface of orange petal fiber should have folds, convex and concave, and the two thermoplastic polymers should bond with each other at the folds, not at the ridges. The energy of high-pressure spunlace can effectively concentrate on the concave part of the orange petal fiber, making the fiber easy to split. In order to achieve better cracking effect, hollow orange petal fiber can also be made.

At present, 16 or 32 orange petal fibers are common. Generally, products with low surface density less than 120g/m2 are produced by spunlace process, and products with surface density more than 250g/m2 are generally produced by needle punching process.

The good web entanglement effect of obtaining high-performance nonwovens depends on the fineness, strength and elongation of the spunbonded filament, the evenness and longitudinal and transverse strength of the web, the water pressure in the spunlace process, the pore diameter of the water needle plate, the pore density, the pore shape, and the number of water needles.

To produce high-quality superfine fiber spunbonded spunlace nonwovens, the fiber opening rate should be 60% or higher, so that some coarse fibers of the nonwovens can have high strength, and a large number of fine fibers can obtain the desired feel and other characteristics.

The combination of spunbonded and spunlaced technology to produce superfine fiber nonwovens is a perfect combination, or "one stone and two birds", which is an appropriate and economical process. When the two processes have the same high capacity and are combined, the production of spunbonded spunlace nonwovens will become efficient and low-cost, and a new generation of high-quality nonwovens will be produced.

Super fine spun viscose spunlace is an innovative technology. The forming and entanglement of the fiber mesh are fast, wide, high output, low production cost and high productivity. And there is no rolling point on the cloth surface. The product feels soft, has good permeability and high strength. Super fine spun viscose spunlace nonwovens are products with more development potential in the future market.

Content source: Yingjie Textile