Rubbing color fastness is a very leather rubbing colorfastness tester important test index, some products or customers, the requirements of this aspect is very strict. Therefore, in the processing, must pay attention to improve the leather textile fabrics rubbing color fastness. How to improve the color fastness to rubbing of leather textile fabrics?
11 feasible countermeasures to improve the color fastness of leather textile fabrics to rubbing.
(1) pay attention to the screening of dyestuff, use those good solubility, combined with a good quality dyestuff, when the conditions allow, it is best to use metal complex dyestuff and alcohol-soluble dyestuff, as little as possible to use acid dyestuff.
(2) Before dyeing, we must remove the dust and chips on the leather surface.
(3)The color should be dyed as accurate as possible, avoid spray dyeing and color mixing afterwards.
(4) When dyeing or top dyeing, the dyeing temperature should be controlled in a high range, generally to 60~65 ℃. When using low temperature dyeing with small liquid ratio, the temperature can be warmed up by replenishing water at the later stage of dyeing, and finally the temperature should be controlled at 60~65 ℃.
(5) When formic acid fixing, there should not be more remaining uncombined dyestuff with leather in the dyeing bath, formic acid should be added slowly in stages, and the fixing rotation time should be extended and the final pH control value should be adjusted down.
(6)When using cationic material to fix the color in the late dyeing stage, the bath should be changed.
(7) Covering the leather blank after color fixing and washing with a small amount of soft filling resin will improve its rubbing resistance color fastness to some extent.
(8) After the dyeing is finished, the water washing should be strengthened to thoroughly wash away the surface floating color and unbound dye.
(9) Reduce the amount of dyestuff as much as possible. Such as the following methods can be used to reduce the amount of dye: pre-dyeing with a small amount of dye before chrome retanning; dyeing first and then filling to avoid serious color defeat; using deepening agents such as rare earth to increase color. The amount of dyestuff is less, and the amount of uncombined dyestuff in the leather is reduced accordingly, which helps to improve the color fastness of suede to rubbing.
(10)If the wet leather is already greasy before top-dyeing, you should remove the grease before top-dyeing, which will help the dye penetrate into the leather fiber and combine with it firmly.
(11)In wet processing, the charge of wet leather should be strictly controlled, because anionic retanning agents (such as tannin, resin tanning agent, synthetic tanning agent) and anionic fatliquor will compete with anionic dyes for the binding point, therefore, excessive neutralization should be avoided and excessive retanning with anionic materials should be avoided. At the same time, it can be considered to strengthen chromium and aluminum retanning appropriately to increase the cationic charge of wet leather and improve the binding rate of dyes and collagen fibers.
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