Catalytic Dyeing Technology Of Reactive Dyes On Cotton Fabric

Reactive dyes are the most common dyes used in cotton fabric dyeing. But the dyes have some problems including high concentration electrolyte, low exhaustion and fixation, long washing process, etc. The project selects tertiary amines with high nucleophilicity as catalyst to improve reactive dyes’ reactivity and realize catalytic dyeing. The project also researches reactive dyes dyeing process with low concentration of sodium sulfate and sodium carbonate and using few power and waste water. The result shows that it will produce reactive dyes with active group quaternization if putting catalysts and reactive dyes with s-triazine together. The reactivity of reactive dyes and cellulose’ hydroxyl is enhanced because that the leaving group’ electronic absorption heighten. As a result, the modified reactive dyes can react nucleophilic substitution reaction with cellulose’ hydroxyl in weaker alkaline dying liquid. Besides, the new process can reduce sodium carbonate dosage, dyeing time and dyeing temperature. It can also improve dyeing depth and dye fixation percentage.Firstly, the project researchs many kinds of tertiary amine compounds’ catalytic effect on s-triazine reactive dye. The project selects niacin, trimethylamine and triethylene- diamine as catalyst. The experiment search suitable catalyst and dyes. Then, it explores the catalytic dyeing mechanism. The result shows that trimethylamine and triethylene-diamine have the better catalytic effect on K reactive dyes.Secondly, the the suitable adding ways and catalytic dyeing conditions are as follows: The adding way of 2%(owf) dyeing concentration is that putting trimethylamine, sodium carbonate, sodium sulfate and cotton fabrics together at the beginning of dyeing. The fixing temperature decreases from 80 ℃ to 60 ℃. Sodium carbonate decreases from 15g/L to 8g/L. Sodium sulfate decreases from 50g/L to 25g/L. The adding way of 5%(owf) dyeing concentration is that putting trimethylamine, sodium carbonate, sodium sulfate and cotton fabrics together at the beginning of dyeing. The fixing temperature decreases from 80 ℃ to 60 ℃. Sodium carbonate decreases from 20g/L to 14g/L. Sodium sulfate decreases from 80g/L to 50g/L; The adding way of 2%(owf) dyeing concentration is that putting triethylene diamine, sodium carbonate, sodium sulfate and cotton fabrics together at the beginning of dyeing. The fixing temperature decreases from 80 ℃ to 60 ℃. Sodium carbonate decreases from 15g/L to 7g/L. Sodium sulfate decreases from 50g/L to 14g/L; The adding way of 5%(owf) dyeing concentration is that putting triethylene diamine, sodium carbonate, sodium sulfate and cotton fabrics together at the beginning of dyeing. The fixing temperature decreases from 80 ℃ to 70 ℃. Sodium carbonate decreases from 20g/L to 12g/L. Sodium sulfate decreases from 80g/L to 45g/L. Besides, the project research the S.E.R.F. of reactive blue K-3R and reactive blue M-2GE due to catalytic dyeing can reduce K reactive dyes’ fixing temperature to 60℃ which is close to M reactive dyes’ fixing temperature. The result shows that the range of reactive blue K-3R and reactive blue M-2GE’s S.E.R.F. from-5% to +15%. So, this 2 type reactive dyes can match and the match have the positive significance in expanding the reactive dyes’ chromatographic scope.Thirdly, compound of trimethylamine and triethylene diamine may have the multistage catalysis on s-triazine reactive dyes because trimethylamine and triethylene diamine have the similar catalytic dyeing conditions. So, the project researches the catalytic dyeing effect of different concentration proportion of catalyst. The result shows that the effect is best when the mass ratio of trimethylamine and triethylene-diamine is 1:3. It can increase K/S of the 2%(owf) dyeing concentration from 2.3 to 4.5.Finally, the project researches that the catalyst as reactive dyes’ reinforcing agent can also further improve the reactive dyes’ degree of fixation even if putting it in dye liquor after fixation process. The project researches the influence of holding time and catalyst dosage on dyeing effects. The result shows that the K/S can increase from 2.3 to 3.2 with 0.6g/L of catalyst dosage and 20 minutes of heat preservation after fixation.