With the development and progress of society, people are increasingly pursuing the color and style of clothes. Although fibers and fabrics can be dyed with bright colors, some dyes have soluble groups, which makes the color fastness to wet friction poor, the fading and staining phenomenon of soaping is serious, and the effect of sweat resistance is not good. The appearance of color fixing agent solves this problem, but the traditional color fixing agent contains free formaldehyde, which will stimulate the skin, lead to inflammation and even ulcer. In serious cases, it will cause cancer, and the sewage discharged from the dyeing process will pollute the environment. In order to solve the shortcomings of poor fixation effect and toxic components of traditional color fixing agents, environmental friendly aldehyde free color fixing agents have become a research hotspot. However, the formaldehyde free color fixing agent on the market has the disadvantages of high energy consumption, complex synthesis operation and limited color fixing
Polydimethyldiallyl ammonium chloride (PDMDAAC) has a linear structure and belongs to polyamine compounds. The structure contains high-density positive centers and is easy to combine with anionic compounds. It is often used in sewage treatment, or as a polycation fixing agent in dyeing process. It is generally believed that the fixation mechanism of cationic compounds is that the positive center reacts with the anionic dye on the fiber through electrostatic attraction, so as to achieve the fixation effect, but this fixation mechanism has not been proved by experiments. In addition, the fixation mechanism of polycation fixing agent is only one effect of electrostatic effect, or the result of several effects acting together; Whether the fixation mechanism can be directly verified by experiments, these practical problems are worthy of further research.
A modified polycationic fixing agent for superfine fiber PU leather was synthesized by using di⁃methyl diallyl ammonium chloride and diallylamine as raw materials, epichlorohydrin (ECH) as crosslinking agent and azodiisobutyronitrile (AIBN) as initiator. The effects of reaction temperature, material ratio, initiator dosage, glacial acetic acid dosage and crosslinking agent dosage on color fastness to sweat were investigated. The results showed that when the reaction temperature was 75 ℃, the mass ratio of raw material dimethyl diallyl ammonium chloride and diallylamine was 100∶7, the initiator was 0.10 g, glacial acetic acid was 1.7 g and the dosage of crosslinking agent was 1.55 g, the color fixation effect was the best. At the same time, it was found that the color fixing mechanism of polycationic color fixing agent was the result of the joint action of the two effects of the reaction of polycationic compounds with anion dye molecules to produce color deposition and the formation of dense polymer film on the fabric surface. The product is used for sweat resistant fixation of microfiber PU leather, and the effect of fixation treatment is satisfactory.
