Porous Styrene-acrylic Latex Film And Its Application In Textile Finishing

Pigment dyeing has the characteristers of simple progress, complete chromatography, convenient post-processing, and without steaming or washing after fixing. It was regarded as an effective way to achieve clean production and energy-saving in the dyeing industry. Adhesives are the important component in pigment dyeing (printing) working liquid. Being environmental benign, the water-dispersed adhesives are widely used in pigment dyeing (printing), functional finishing and other areas. During the baking process, the adhesive forms film on the surface of the fabric, where the paint or other finishing materials are fixed onto the fabric. However, it leads to a decrease in the air permeability of the fabric. So, the wearability and comfortability of finished fabrics are closely correlated to the properties of the engaged adhensives. Aiming at solving those problems, styrene - butyl acrylate copolymer latex with designed mophologies was synthesized. And some water soluble polymers were fed into the latex. The effects of the particle morphology, as well as the added polymers, on the film forming process and the film structure were investigated. The distribution of the sodium dodecyl sulfate (SDS) in the films was also studied finally. The followings are concluded:Latex particles with core-shell morphology were prepared by a batch-semibatch two stage miniemulsion polymerization technology. The crosslinking degree of the middle layer of the polymer was controlled by the crosslinker concentration in the feeding stream. It is found that the continuity of the film decreased greatly with the increase of the crosslinking degree, and the contour of the initial particles are more obvious, which leads to the fracture of the final films.It was found that the drying process could still be divided into three stages even after the addition of PVP and PEG. And the water evaporation rate during the first and the last stage remained the same as usual. However,after the addition of PVP, the onset of the second stage was delayed to high volume fractions. Finally, PVP formed into dispersion phase. The size and the morphology were greatly determined by the concentration and the molecular weight. When the concentration was less than 15%, the PVPK30 (Mn=10,000 g·mol₁) phase appeared as"finger-like"structures. It changed into near spherical structure as the concentration increased to 15%. However, tensile analysis showed a decrease in tensile breaking strength of the films. A different case was found after the feeding of PEG. Firstly, the first stage ended at low volume fraction and a decreased evaporation rate was observed in the second stage. Secondly, the PEG dispersion appeared as"finger-like"in the TEM picture with 6.6μm in length. But the effect of PEG on the tensile breaking strength was similar to those of PVP. After rinsing, pores were found in the films formerly containing PVP or PEG. While the shapes and the sizes were closely correlated with the initial morphologies of the PVP or PEG dispersion. The PVP or PEG modified latex were used in fabric finishing and pigment dyeing, the air permeability of the finished fabrics remarkably improved after rinsing, which is even comparable with the non-finished fabrics. The shade and rubbing fastness of the dyed fabrics are little affected by PVP or PEG.The relative concentrations of SDS at film-air (F/A) and film-substrate (F/S) interface of the resulting St-BA copolymer latex films were also analysized by ATR-FTIR technique. It was found that: the concentration of SDS at the F/S was always much higher than that at F/A interface, and it migrated very easily.