The composite fiber is a melt of two or more polymers, divided by a special distribution plate, and extruded through the same spinning hole. There are hundreds of composite fiber varieties, and there are also many classification methods. According to the production method, they can be divided into composite spinning and blended spinning. There are 5 types commonly used according to the form of spinning: co-spinning, side-by-side, and sheath-core. Split type, island type. Polyester / nylon composite fiber, which has the advantages of nylon's abrasion resistance, high strength, easy dyeing and moisture absorption, but also has the advantages of good elasticity, good shape retention, stiffness and no ironing. The general composite spinning is mainly based on polyester-nylon composite, which has orange-shaped, rice-shaped and other shaped cross-sections, and has good hygroscopicity. It is mainly used in cleaning supplies and home textile supplies. In addition, the low melting point, flame retardant, antistatic, and conductive functions of many fibers are also achieved by the special structure of composite spinning.
Production technology of polyester-nylon composite ultrafine fiber
01. Production method of polyester-nylon composite ultrafine fiber
Polyester / nylon composite ultrafine fibers are made by melt-spinning at a certain ratio in the production process, taking advantage of the differences in the chemical structure of the two polymers, PET and PA, and their interface binding strength, which can be separated from each other. Generally, antimicrobial ultra-fine fibers are added to chemical fibers by blending or adding masterbatch to obtain permanent antibacterial effect. Compared with the antibacterial finishing technology, the antibacterial fiber has good antibacterial effect and durability, the fabric weaving, dyeing and finishing process is simple, the fiber does not attach resin, and the finished fabric has a good feel. However, this method has high technical content and great difficulty, especially high requirements for antibacterial agents. In addition, most organic antibacterial agents are not resistant to high temperatures and are difficult to use for melt spinning. Inorganic antibacterial agents, such as antibacterial phosphates, glass, ceramics, and oxides, have unique high temperature resistance. They mainly pass through the contained silver , Copper, zinc and other metal ions antibacterial effect to achieve antibacterial and deodorizing effect. Relevant domestic enterprises applied the antibacterial agent containing silver inorganic phosphate and metal oxide to the production of polyester-nylon composite ultrafine fibers, and adopted the production technology of antibacterial masterbatch and fiber slice blending spinning to produce antibacterial polyester-nylon composite Microfiber and antibacterial fabric. The antibacterial material is made of inorganic antibacterial agent (containing silver 3% phosphate and metal oxide mixture, average particle size 400nm), and the spinning grade resin chips are made of domestic superfine denier nylon chips and domestic superfine denier polyester chips. The melt spinning method uses the masterbatch addition method to produce melt spun antibacterial polyester / nylon (80/20) composite ultrafine fibers. The antibacterial masterbatch is added to the polyester component at a rate of about 2% of the base material. The process route adopts the high-speed spinning technology of composite fibers and the POY-DTY two-step process. The average single fiber produced by this method is about 0.2dtex, which is equivalent to 1 / 5-1 / 10 of silk, which can give the fabric good physical and chemical properties, and is widely used in textile cleaning supplies and clothing industry.
02. Application technology test of polyester-nylon composite ultrafine fiber
The antibacterial properties of the industrially produced antibacterial polyester-nylon composite ultrafine fiber DTY filament and its warp knitted fabric dyed products were tested. The antibacterial test adopts the Japanese JIS L 1902 standard to carry out antibacterial tests on Staphylococcus aureus, Pneumococcus and Escherichia coli respectively. The test results show that the antibacterial effect of the fiber and the finished fabric of the dye have reached the blue and orange of the Japan Fiber Evaluation Technology Association The standard requires a high antibacterial effect. This action shows that the silver-containing inorganic phosphate and metal oxide micropowder antibacterial agent can be applied to the industrial production of antibacterial polyester-nylon composite filament ultrafine fiber melt spinning, thereby opening up a new way of functionalized and differentiated fiber production . The antimicrobial ultrafine fibers produced by this antibacterial masterbatch melt spinning technology and POY-DTY two-step process have good physical and mechanical properties and antibacterial effects. The technology is feasible, the process is reliable, and the quality index of the finished warp knit fabric is excellent. The actual production of antibacterial ultrafine fibers can better solve the problem of easy discoloration of the fibers produced by inorganic antibacterial agents, and the color difference and yellowing index of the finished dyed products all meet the actual production requirements.
Warp-knitted fabrics were produced in batches with antibacterial polyester-nylon superfine fibers, and the dyeing and finishing process was studied. The quality of the finished dyeing products is excellent. The ISO standard is used to test at 95 ° C. The shrinkage rate and color fastness indicators are in line with actual needs, especially the excellent shrinkage resistance. In addition, a chemical fiber enterprise in Guangdong Province has cooperated with the American Hills Company to successfully carry out technical transformation of the traditional polyester POY spinning production line of 12 × 8 parts. The transformed production line can also produce island-type and split-type bicomponent composite fibers. And the production is normal and stable, and the product quality fully meets the requirements. The company has also carried out technical cooperation with South Korea, Taiwan and other related companies to carry out the technical transformation of the traditional polyester POY spinning production line to produce single-component ultrafine fibers. The goal is to make the single fiber fineness of the product less than 0.35dtex. In this way, the use of the traditional polyester POY spinning production line to produce polyester-nylon composite filament antibacterial microfibers and fabrics has broad development space.
03. Dyeing performance of polyester-nylon composite ultrafine fiber
The new synthetic fibers represented by ultra-fine fibers, because of the monofilament fineness, cross-sectional morphology, surface morphology, shrinkage properties, and polymer structure (chemical structure, crystallinity, orientation, etc.), are significantly different from conventional synthetic fibers. Therefore, there are many differences between the new synthetic fiber fabric and the conventional synthetic fiber in the spinning, weaving, dyeing and finishing processes. Adding leveling agent in the dyeing process is an important way to improve the dyeing performance of ultrafine fibers. Domestic companies have found in the production process that adding leveling agents to the dyeing liquor can increase the solubility of disperse dyes in water, increase the proportion of single-molecule state dyes, and help improve dyeing performance. It shows that the leveling agent has a solubilizing effect on the disperse dyes, that is, it increases the amount of single-molecule and micellar dyes in the dyeing solution. The single-molecule dye in the dyeing solution is the main form of dyeing fibers, and the ratio of micelle-like dyes Dye crystals are easier to release dye monomers, which are conducive to uniform dyeing. At the same time, the presence of leveling agent also helps to improve the high-temperature dispersion stability of disperse dyes, less color flowers and color dots. This is because the specific surface area of the ultra-fine fibers is large, and the adsorption rate of the dye is also very fast, which easily forms uneven dyeing. For polyester / nylon composite filament antibacterial ultrafine fibers, the single fiber specific surface area is not only larger. And the difference is also very large, it is more likely to cause differences in dyeing rate, the result is easy to dye flowers. Therefore, controlling the dyeing rate is one of the keys to disperse dyeing of ultrafine fibers. When the leveling agent is not added, due to the large difference in the dyeing curve of different disperse dyes, the dyed color flower and color difference are caused during dyeing. If the disperse dye transfer effect is not obvious, these defects will not be overcome. After adding leveling agent, the up-staining curves of different disperse dyes can be made closer. This is very important for color matching.
The researchers found that an important way for leveling agents to improve the dyeing performance of ultrafine fibers is to improve the dyeing curve of disperse dyes, reduce the difference between the dyeing curves of different disperse dyes, and thus improve the compatibility between dyes. This is very important for the color matching dyeing, because when the dyeing rate of the disperse dyes for color matching becomes basically the same, it can ensure the gradual progress of the same color, reduce the chance of color difference, and the reproducibility of the dyeing will be better.
