Study On The Discoloration Mechanism And Fastness Improvement Of Cotton Fabric Dyed By Reactive Dyes Under Light-perspiration Conditions

Reactive dyes are the main dye for dyeing of cotton fiber.Some reactive dyes dyed cotton fabrics show poor light-perspiration fastness,leading to serious fading and discoloration of outdoor textiles during the wearing process,which is difficult to meet the production requirements.Therefore,there is an urgent need to improve the light-perspiration fastness of reactive dyes.In addition,the test method for light-perspiration fastness in GB/T 14576-2009 is not only complicated,but also subjective,which seriously affects the efficiency and accuracy of analysis and testing.In order to solve the above-mentioned problems,the article takes the C.I.Reactive Black 5,C.I.Reactive Blue 222,C.I.Reactive Red 195 and C.I.Reactive Blue 19 as the research objects.By establishing a simple evaluation method,then researching on the key factors affecting the light-perspiration fastness,and the designing and developing of light-perspiration fastness enhancers,reveal discoloration mechanism and fastness improvement of cotton fabric dyed by reactive dyes under light-perspiration conditions.The main research content of this paper includes: 1)Changing part of the experimental conditions in the national standard method,the feasibility of the paper substitution method,solution illumination method,and ultraviolet aging method are studied respectively,and K/S and?E of dyed fabrics are used as evaluation indicators to replace the subjectivity in the national standard method,exploring how to improve the evaluation efficiency of light-perspiration fastness,so establishing a simpler,efficient and objective evaluation method;2)Analyzing degradation of dyes by components in artificial sweat and degradation of dyes by acid-base in artificial sweat,then studying the key influencing factors of light-perspiration fastness;3)Based on the use of liquid chromatography and mass spectrometry,investigating the effect of anti-oxidant HALS-1and anti-reducing agent sodium m-nitrobenzene sulfonate,and exploring the discoloration mechanism of cotton fabric dyed by reactive dyes under light-perspiration conditions;4)Choosing and synthesizing the light-perspiration fastness enhancers that can inhibit dye degradation,and exploring effective methods for improving light-perspiration fastness of reactive dyes.The research results show that:Using "ultraviolet aging method + K/S and ?E method" instead of " the GB/T 14576-2009method" can significantly improve work efficiency and evaluation objectivity.Acidity and alkalinity of the artifical sweat have a greater impact on light fastness.The stronger the acidity or alkalinity,the worse the light-perspiration fastness of reactive dyes.In the GB/T 14576-2009,acidic sweat 1 with p H 4.3 has the greatest impact;the influence of different components in sweat is different,it is L-histidine hydrochloride monohydrate> lactic acid> sodium chloride.The fading mechanism of reactive dyed cotton fabrics under light-perspiration conditions is revealed,which is reactive dyes main mechanism are photoreduced on cotton fabrics under sweat and light conditions.After finishing dyed cotton fabrics with reactive ultraviolet absorbers TF-6160 and TF-6162 and reactive anti-reduction agent A,the fabric fading rate and ?E have been significantly improved with using light and the acid perspiration 1 in GB/T 14576-2009.Among them,the effect of reactive anti-reduction agent A is the most significant,the fade rate is reduced from 23.50%before finishing to 10.58%,and the ?E improvement rate reaches 43.48%.