Study Of Alkaline Colored Burnt-out Printing With Disperse Dyes In PET Raised Fabric

Colored burnt-out printing product of raised fabric of polyester is popular with customers because of its gorgeous appearance,stereoscopic pattern and fine touch.Burnt-out is achieved by caustic soda based on the poor alkali resistance of polyester fibers.Partial fabric is corroded,which brings stereoscopic effect.If it can be colored when burnt-out,more colorful design effect will be gotten.However,PET raised fabrics generally need to be colored after burnt-out due to poor alkali resistance of disperse dyes,which leads to complex processes and high cost.In order to make alkaline colored burnt-out printing one step process possible,the stability of disperse dyes in different alkaline conditions were studied.Combining visual inspection,the screening rules were made and a series of alkaline stable disperse dyes were obtained.The relationship between dye structure and their alkali resistance were explored.In addition,the formula of colored burnt-out paste was prepared and the process conditions were optimized.Thus,an ideal technique of Alkaline colored burnt-out printing with disperse dyes in PET was developed.Absorbency curves of different disperse dye baths which were treated in the condition of 120?,0-10g/L sodium hydroxide were studied.According to the characteristics of the visible light absorption of different disperse dyes their alkali resistance were analyzed.The smaller changes in absorbency curves after the high temperature alkali treatment means better alkali resistances of disperse dyes.The wavelength of maximum absorption,K/S value and color shading ?E of colored burnt-out fabrics in concentration of 25% sodium hydroxide and direct printing fabrics were compared and a screening rule was made.Combined with the alkali resistance study of disperse dyes in baths,the following 10 disperse dyes with good alkali resistances were selected.They are Disperse Red SXF,Disperse Magenta HA-B,Disperse Deep Red SA-6B,Disperse Yellow SXF,Disperse Yellow SA-RL,Disperse Bright Yellow SA-GL,Disperse Diamond Blue A-BR,Disperse Navy Blue A-BT,Disperse Blue HA-2R and Disperse Blue SA-GBL.And the result was nearly consistent with the one in dye baths.The paper compared High-performance liquid chromatograms and Infrared spectrums of Disperse Red SXF(Benzothiazole azo dyes),Disperse Bright Red SXF(Benzothiazole azo dyes)and Disperse Yellow SXF(monoazo dyes)before and after high temperature a nd alkaline treatment.The result indicates that the main structures of the three have little effect on their alkali resistance,while the hydrolysis groups affect significantly.Dyes with ester group hydrolyze easily which results in poor alkali resistance.However,the alkali resistance of cyanogroup is better than ester group.Higher electronegativity of N atoms in cyano means more reactive the cyano is.The electron conjugation effect in diazo component of azo dyes makes the charge in the system more dispersed.Then the electronegativity of N atoms in cyano of coupling component decreases,which brings poorer hydrolysis ability of cyano and good alkali resistance of the dyes.Alkali stable disperse dye blue A-BR was selected for colored burnt-out printing in PET raised fabric.The influences of properties of paste,concentrations of sodium hydroxide and auxiliaries on the effect of colored burnt-out printing were explored.It shows that paste D-10 has good alkali stability,storage stability and water holding and brings good colored burnt-out effect to PET raised fabric.Burnt-out effect was very obvious when the dosage of caustic soda was 25%.Increased dosage of caustic soda does little to the improvement of burnt-out effect but leads to decreased bursting strength.Nonionic anionic surfactants are suitable for colored burnt-out printing process.Therefore,the formula of paste was determined: disperse dye is 2%,paste D-10 is 35%-37%,sodium hydroxide is 25% and penetrating agent 107 is 3%.Influences of printing parameters on unit area paste add-on,colored burnt-out effects and pattern edge sharpness were studied.The result shows that,the increased magnetic-rod diameter and decreased speed of printing make the paste add-on and weight loss rate higher,but leads to the decreased pattern edge sharpness.Yet the effect of magnetic force on the printing is slightly less than the former two.When magnetic-rod diameter is 12 mm,magnetic force is 3#,printing speed is 1 m·min-1 and unit area paste add-on is 133-135 g·m-2,the colored burnt-out effect of fabric is excellent.In addition,baking conditions were optimized.The optimized baking temperature is 190 ? and baking time is 3 min.Ten alkali stable disperse dyes selected above were applied to make burnt-out printing product of raised fabric of polyester.Their soaping fastness and color fastness to rubbing were all above grade 3 and most of them were grade 4 or grade 4-5.And bursting strength loss of the fabrics were within 35%.The paper produced brightly color,clear pattern and excellent stereoscopic effect on raised fabric of polyester.It has import practical meaning.