Control The Fastness Of Nylon-spendex Elastic Knitting Fabrics

Nylon-spandex elastic knitting fabrics are widely used for swimwear,underwear andsportswear,and they are favored by consumers because of their excellent performance.Nylon-spandex elastic knitted fabrics dyeing with the weak acid dyestuffs and theneutral dyestuffs mainly. In weakly acidic conditions, the dye molecules combine with nylonmolecules through ionic and hydrogen bonds and Van der Waals’force, at the same time, dyemolecules will contaminate the spandex.In the process of setting and finishing,with thetemperature and auxiliaries migration,the dyes will remove to the surface of the fabrics. In wetfastness tests conditions dyes will dissolve in water or migrate to the test standard crinoline,forming staining seriously.This paper analyzes the reasons according to the dyestuffs,auxiliaries,the dyeing andfixing processes,which lead the fastness inconsistent,and find the solution from many tests.The structure of the dyestuffs determine the chlorine-resistant fastness.Leveling agent,fixing agent and fixative pH values will impact the chlorine-resistant fastness. Though thespecific fix agent which can improve the chlorine-resistant fastness obviously, but it’s notwashable, and the light fastness of the fabrics will lower after process.So it is notrecommended for a general process.Light fastness mainly decided by the structure of the dyestuffs, the influence of variousauxiliaries is mild. Theoretically, the light fastness booster can boost the bond energy betweenthe dyes and fibers to resist decomposition of dyes.Reality, the role of such substances isextremely weak and even less than0.5degree.The wet fastness of Nylon-spandex elastic knitted fabric can be improved byfixation.The fixing agents contain anions and cations,Anionic fixing agent is used in the dyevat, temperature, time and pH value will make influences on the treatment effect.Cationicfixing agent is used in the process of finishing.Synergies between the two kinds of fixingagent can improve the fastness resistance to washing, water, perspiration and sea water.The other aspect to guarantee the fastness of nylon-spandex elastic knitting fabrics is tominimize the impact of finishing.For example, reduce the negative effect of temperature andagents on color fastness.The paper skiped this part.Some conclutions had applied in the production,the chlorine-resistant fastness of bluecolors improve1-1.5degree,and the wet fastness of dark colors improved0.5-1degree.