nlwxpearo
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 Posted: Mon 1:22, 03 Jan 2011 Post subject: Scouring and bleaching linen knitting yarn process |
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Linen knitting yarn of scouring and bleaching process
Normal, the cans are closed, circular heated to 8O ℃, the pressure in the 2 for 3 to 4 hours. Scouring is completed, first the pressure reduced to 0, let go of lye, the 8O ℃ hot water, then cold water. 1.2 Bleaching of sodium hypochlorite 2.0g / l sodium nitrate 08g / 1 3O ℃ temperature value of 9.5 ~ lO time 30minDH sodium hypochlorite bleach, using appropriate technology, with less damage to the fibers. Require a higher degree of some white yarn,[link widoczny dla zalogowanych], often with heavy chlorine bleaching, light oxygen bleaching process, and strive to avoid excessive damage of yarn strength. 4 2000 51.3 Heilongjiang Textile finishing processes in the alkaline bleaching of yarn after the state, taking into account performance. So to the yarn acid: acetic acid lg / l, temperature 45, time 5rain, when pH = 7, add softener (5%), temperature 7O ~ 8O, time 30min, dehydration and drying. 2 Experimental results and analysis of Yama fiber belongs to Shu fiber, Chu containing 90% cellulose, but also contains pectin, ash, wax, hemp particles, and impurities, these impurities Cunzai a direct impact on Asia Masha in the high-stitch knitting Heng machine on the application, must be scouring process to remove these impurities + can help the knitting yarn. However, under the action of concentrated alkali, destroy the pectin,[link widoczny dla zalogowanych], cellulose fiber cohesion to decrease, thereby reducing the strength. Process by the scouring of flax yarn, the alkali concentration is too high,[link widoczny dla zalogowanych], a longer processing time,[link widoczny dla zalogowanych], resulting in greater strength loss. DH value of the bleaching solution quality of the bleaching effect is very important, uH values decrease, faster bleaching of cellulose will be more serious injury, is not conducive to knitting yarn, ~ like to control the DH value of 9.5 ~ 10 room. Bleaching temperature increased, although the bleaching rate was increased, but the rate of oxidation of flax fibers are also improved, and a lot more than the bleaching rate of increase is very significant, the higher the bleaching temperature will lead to greater damage by cellulose Therefore, in the actual production, the bleaching temperature is usually maintained at about 3O. Too long, injury fiber; time is too short, bleach does not thoroughly, uneven, it is usually the time set for 30rain. Bleaching is also an important factor in the concentration, the concentration too low to bleaching requirements; concentration is too high is a waste of drugs, and serious injury fiber, therefore, the concentration of bleaching solution and other conditions must also be compatible. Under the action of the lye, flax fiber in the shape of the cross section has changed and improved softener and the dye uptake rate, therefore, scouring and bleaching linen knitting yarn The optimum choice for: lye, bleach concentration moderate; time not too long; temperature can not be too high; bleaching solution DH value can not be too low, to reduce the loss of strength, the overall strength loss control within 20% to meet the needs of knitting yarn. 3 Conclusion After a number of technology test and production practice, to explore a reasonable linen knitting yarn scouring and bleaching process route and process parameters. Scouring and bleaching process compared with the past, greatly reducing the strength loss of flax yarn, knitting yarn to meet the requirements, but also for linen knitting laid the foundation for industrial development. Received date: 1999 A I2 ~ l4 (on the next page 6) chelate type of organic stabilizer too multivalent chelating agents can cooperate with the sting of metal ions to form stable water-soluble with a sting complex, the metal catalysis does not occur. Carboxylic acid salts such as EDTA, HEDTA (hydroxyethyl ethylenediamine triacetic acid), DTPA (diethylenetriamine pentaacetic acid) are less effective, expensive, carboxyl hydroxyl, such as GAS (gluconate) complexing ability . But the biggest drawback Chelation type can not be as absorptive, as the metal ion concentration can and can not chelate metals other than the catalytic decomposition of hydrogen peroxide impurities. Therefore, the stability of single-oxygen bleaching agent in the use of a single function has been mainly the adsorption and sequestration must be mixed with stabilizers. Adsorption of such stabilizer type and concentration of chelating type of advantage, get rid of its shortcomings, to high temperature, alkali, white high requirements. Sorption and chelation-based stabilizer mixture according to a certain molar ratio, supplemented by some non-ionic surface active agent, protective agent and a small amount of polysaccharide fiber glass,[link widoczny dla zalogowanych], oxygen bleaching process in a single complex stability by adjusting the composition Jing and hydrogen peroxide dosage on the different quality of flax can reach the required brightness. Especially for special coarse linen fibers can also be the maximum range (30% to 40%) increase the concentration of alkali, in order to achieve the roving can be spun and whiteness. Therefore, semi-bleached linen roving and using a single oxygen bleach mixed oxygen bleaching stabilizer is a trend. This process not only saves a lot of chemical materials and funds, but also conducive to environmental protection and improve the operating environment of workers, shorten the process, the quality of spun yarn structure is not in any way. Animal husbandry, issued Date :1999-12-15
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