Study On Disperse Modification Of Thermochromic Microcapsules And Its Padding Finishing On Cotton Fabrics

Thermochromic textiles are a new type of functional textile that can change color with the change of temperature.Its appearance is in line with the individualized demands of modern people pursuing fashion and eager to innovate.It mainly uses thermochromic microcapsules to realize the principle of color-changing.Because microcapsule color paste is easy to precipitate and can't be stored for a long time,it needs to be produced and used immediately,etc.At present,its production still has certain limitations and it's not completely marketed.Therefore,it is a necessity to study and solve the dispersion stability of microcapsules in order to facilitate its long-term stable storage and use in the field of thermochromic textiles.This thesis aims to explore the dispersion stability of melamine formaldehyde resin(MF)microcapsules in aqueous systems and their applications in the field of thermochromic fabrics.In the paper,the dispersion stability of unmodified microcapsules was first studied.The single-factor experimental method was used to discuss the effect of different dispersion processing parameters on the dispersion stability of microcapsules.The optimal dispersion processing parameters of microcapsules was determined.Then the coupling agents KH550 and KH560 were used to modify microcapsules and study the dispersion stability of the modified microcapsules in the aqueous system.Finally,the microcapsule color paste with better dispersion stability was used on pure cotton woven fabric to realize fabrics' reversible color-changing by padding method,using orthogonal design method to study the effect of binder content,rolling ratio,baking temperature and baking time on the single properties of fabrics.When the multiple properties of the fabric are comprehensively evaluated,the optimized finishing processing parameters are obtained according to the orthogonal design multi-index evaluation method(integrated balance method).The main findings of the paper are as follows:First,microcapsules were dispersed to us different kinds and dosage of dispersants to study the dispersion stability of the unmodified microcapsules in aqueous systems under different dispersion conditions.Through experiments,it was found that when the mass ratio of dispersant BYK-190 to microcapsule paste are 50%,ultrasonic dispersion time are 30 min,pH of aqueous system are 7,mixing speed are 3000 rpm,and mixing time are 1 h,the dispersion stability of microcapsule color paste is better;Secondly,the microcapsules were modified by different concentrations of coupling agents KH550 and KH560,and it was found that the surface smooth and dispersity of microcapsules modified with 2% concentration of coupling agent KH550 and 1% concentration of coupling agent KH560 are better,and then the modified microcapsules are dispersed by different kinds and dosage of dispersants to study the dispersion stability in the aqueous system.And it was found that the dispersion stability of the microcapsule paste modified by the coupling agent KH550 are poor and the hydrophobic phenomenon of the microcapsules was serious.The stability of the microcapsule paste modified with coupling agent KH560 are better compared the coupling agent KH550.However,its stability does not reach a desired ideal state that the absorbance ratio is less than 90%,and some microcapsule agglomerates in the color paste are not dispersed;After that,the dispersed microcapsule paste was finished on the pure cotton plain fabric of cationic modification by padding method,and studies the influence of different factors on the single properties of the fabric with orthogonal design method.The multiple index evaluation orthogonal design analysis method(integrated balance method)was used to choose the optimal process parameters for fabric color-changing finishing that the binder content is 20%,the rolling rate is 80%,the baking time is 3min and the baking temperature is 100 °C;Finally,the fabrics are finished by the above-mentioned optimization process parameters with the undispersed and dispersed microcapsule paste.The experimental results show that the surface of the fabric after finishing with the undispersed microcapsule color paste has some microcapsule particles and an uneven color,besides the fabric has a poor dry and wet rubbing fastness and washing fastness,and the color-changing sensitivity is relatively low.The color of finished fabric with dispersed microcapsule color paste are darker and uniform,and the dry and wet rubbing fastness and washing fastness of the fabric are better,the discoloration performance is also better,but the air permeability and hand feeling are slightly lower than that of the unfinished raw cotton cloth.