Advantages of pure liquid ammonia finishing
Liquid ammonia mercerizing finishing is an innovative finishing method that improves fiber function, characteristics and feel. The fabric treated with liquid ammonia becomes plumper, more elastic, softer and smoother to the touch, has increased color fastness, gloss, silky feel, and improved tensile and compressive strength. Reduce natural distortion, make the yarn smoother and smoother, greatly reduce the resistance to fabric rebound, and greatly improve the anti-wrinkle performance.
This treatment not only has the effect of mercerization, but also overcomes the erosion and unevenness that may be caused by traditional caustic soda mercerization. Liquid ammonia treatment has now become an important means of high-grade fiber treatment.
denim, shirting, linen and other fabrics treated with liquid ammonia can immediately improve the grade of the company’s textile products, playing a positive role in the company’s comprehensive competitiveness and its own brand effect.
[Caustic soda] mercerization, known in the textile field, aims to increase physical, chemical-physical, optical and Sensory properties to change some properties of cotton. In addition to [caustic sodium], anhydrous ammonia can also bring a mercerizing effect to cellulose fibers, and it can give cellulose fibers better characteristics. This special effect cannot be obtained through ordinary alkali mercerization.
The main performance characteristics that can be obtained through ammonia treatment are as follows:
1. Ammonia treatment will not reduce the strength of the fiber. , and the mechanical properties of the fiber (such as abrasion resistance, tensile resistance, tear resistance) are strengthened without changing the feel of the fabric. The fabric can still maintain a soft feel even after being washed multiple times.
2. The ammonia treatment causes the fibers to expand slightly. The treated fabrics show stronger plasticity and ductility when they withstand the stress caused by wear and repeated washing. The lifespan and “new” appearance of the garment can be extended and maintained. At the same time, the difference between this kind of expansion after alkali mercerization and ammonia treatment is that alkali mercerization produces a shiny surface on the fabric surface, but ammonia-treated fabric surface produces a satin effect, but the gloss is darker.
3. Since ammonia molecules are smaller than [caustic soda] molecules, the penetration of caustic soda into the fiber cannot reach the depth of ammonia penetration, which will make the treatment more uniform, regular, effective and simultaneous. Qualitative. The fabric will not gradually shrink when washed, and the color will not change.
The above characteristics are sufficient to illustrate that ordinary alkali mercerization cannot be compared with [liquid ammonia mercerization] treatment.
[Note: [Caustic soda] is [sodium hydroxide], the chemical formula is NaOH, commonly known as caustic soda and caustic soda , [Caustic soda] is a highly corrosive strong alkali, generally in the form of flakes or blocks, easily soluble in water (it releases heat when dissolved in water) and forms an alkaline solution. It is also deliquescent and easily Absorb water vapor (deliquescence) and carbon dioxide (deterioration) in the air, and add hydrochloric acid to check whether it has deteriorated. 】
The main differences between alkali mercerization and liquid ammonia finishing of cotton fabrics
1. Cotton fabrics after mercerization with caustic soda solution The dye uptake rate is higher and the gloss is stronger, but the dye uniformity is slightly worse. After finishing with liquid ammonia, the dye uptake rate during dyeing is not as high as that of alkali mercerization, and the gloss is not as good as that of alkali mercerization. However, cotton fabrics treated with liquid ammonia have good flammability and soft luster.
2. Fabrics treated with liquid ammonia have good dimensional stability and less discoloration. Despite multiple washes, the size changes remain minimal.
3. Liquid ammonia finishing hardly damages the fiber, but can improve its wear resistance and tear strength. When mercerizing with caustic soda solution, not only will the cotton fibers be somewhat damaged, but the weight will also be reduced by more than 10%.
4. Liquid ammonia can instantly penetrate into the interior of cotton fibers during fabric finishing, causing the cotton fibers to bulge evenly. After finishing, the liquid ammonia is easily removed. The process is simple and energy-saving.
Theoretical research on liquid ammonia finishing technology for textiles began in the 1930s and was officially put into industrial production after the 1970s. Initially it was only used for yarn finishing, replacing the mercerizing technology of yarn. Since liquid ammonia has extremely strong permeability to the opposite fiber, the ammonia liquid remaining on the yarn is easier to remove than alkali liquid, and the mercerizing effect is better than liquid alkali liquid, so it has attracted attention.
Liquid ammonia finishing is called “liquid ammonia mercerization”. In fact, the mechanisms and effects of the two finishing processes are different. When cotton fiber is treated with liquid ammonia, liquid ammonia can instantly penetrate into the fiber, causing it to expand from the core. The cross-section expands from flat to round, the cavity becomes smaller, and the surface is smooth. Due to the change in the crystal structure of the fiber, the internal stress is eliminated and no longer twisted, thereby improving the tensile strength and tear strength. Liquid ammonia finishing of cotton cloth shows its unique advantages as it can still maintain a good feel even after repeated washing. In the laundry chain, liquid ammonia finishing and mercerizing finishing are both finishing technologies for cotton fabrics, but their characteristics and effects are still somewhat different.
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Conclusion
Technical transformation is the most concerning measure for enterprise development. Ammonia finishing was once a technical transformation project that some printing and dyeing companies paid attention to. Through the understanding of the development history of liquid ammonia finishing technology at home and abroad over the years, many companies have a relatively comprehensive understanding of this. After all, liquid ammonia finishing is a high-tech , high investment, high risk technology, so do a good job in domestic and foreign market research, determine the product based on the market, determine the process based on the product, and ultimately determine the equipment based on the process, comprehensively analyze the specific situation and conditions of the enterprise, and do a scientific and economical , reliable comprehensive balance, careful planning of the company’s technological transformation direction and projects is very necessary. </p
