Removal of silicone softener on knitted finished fabric
Jul 26, 2019
Removal of silicone softener on knitted finished fabric
In recent years, silicone softeners have developed rapidly and are widely used in the soft finishing of high-grade knitted fabrics. Silicone softener can give the knitted fabric a soft, smooth, full and elastic hand, as well as anti-wrinkle, abrasion resistance, washing and sewing, and greatly enhance the added value of the product, which is favored by customers.
The silicone softener is chemically stable and belongs to a water-insoluble macromolecular structure. It has strong surface absorbing ability, and some reactive groups form chemical bonds with the fibers or self-crosslink, forming a highly polymerized elastic network structure on the fiber surface. Therefore, it is difficult to remove the silicone softener on the knitted finished fabric by the conventional method. However, the rate of dyeing and repairing of knitted fabrics is higher. If the silicone softener is not removed, the counterstaining or repairing fabrics will not be colored at all. If the removal is not clean, it will cause obvious color, only The silicone softener on the reworked cloth is removed for counterstaining and repair. After repeated trials and large-scale production promotion and application, a method for effectively removing the silicone softener on the knitted finished fabric was found.
1 removal method test
1.1 Test materials and equipment
Cloth: polyester knit fabric, polyester/cotton blended knit fabric, cotton knit fabric
Reagents: Silica DM-1741 (Shunde Demei), silicone softener SA (South Sea Saite), caustic soda (industrial grade), soda ash (industrial grade), Alcoa AD (ciba), 27.5% hydrogen peroxide (industrial) level)
Equipment: Overflow Jet Dyeing Machine (Hong Kong Lixin)
1.2 Test results and discussion
The silicone softener removal test was carried out on polyester-woven fabrics, cotton-knitted fabrics and polyester/cotton blended knitted fabrics with different formulations. The results are shown in Table 1, Table 2 and Table 3, respectively.
The effect rating in the table is 1-5, which corresponds to the removal effect of the silicone softener in the order of poor, poor, medium, good and excellent. When the removal effect reaches level 4, the dyeing and repair of the cloth will not appear color.
2 results and discussion
(1) The polyester fiber molecules on the polyester-knitted fabric do not have polar groups such as hydroxyl groups, and the alkali-strong caustic soda combined with the silicon-eliminating agent can remove the silicone softener on the cloth surface to a level of 4, and the cloth is counter-dyed and returned. There will be no color flowers.
The effect of removing the silicone softener by Alcosan AD (acrylic quaternary ammonium salt) and silica gel DM-1741: polyester polyester knitted fabric grade 5, polyester/cotton blended knitted fabric of grade 4 or above. The reason is that Alcoa AD can dissolve the aminosilicone emulsified and then cooperate with the function of removing silicon spirit, and the effect is better.
(2) Cotton knit cotton fiber has a large number of hydroxyl groups on the molecule. The first four methods in Table 2 are not satisfactory. Only 27.5% hydrogen peroxide is used, combined with Alcoa and caustic soda, which destroys the formation of aminosilicon and fiber. Chemical bond or self-crosslinking can achieve the effect of fully emulsifying and dissolving the silicone softener.
(3) Polyester/cotton blended knitted fabrics contain both polyester and cotton fiber molecules. Under the comprehensive comparison, the removal effect of Alcosan AD combined with SiGeling DM-1741 is the best.
(4) It has been verified by experiments that the removal method is not only suitable for removing the silicone softener SA, but also for removing most of the commercially available silicone softeners.
The above method is applied to the whole production of polyester, cotton and polyester/cotton blended knitted fabrics, which effectively solves the problem of light, medium-color counterstaining and repairing color of knitted fabrics after soft finishing of silicone softener. The problem of high probability of staining silicon spots has been recognized and applied by the knitting bleaching and dyeing factory.
