Fabric Technology: Introducing The Compound And Its Synthetic Method Of Wool Fabric Shrink Proof Finishing.

(1) interfacial polymerization

In this method, wool is dissolved in two amine of water and then treated by two acyl chloride or two ISO nitrile ester dissolved in organic solvent (which is insoluble with water), resulting in polymerization of water and non-aqueous interface on the surface of the fiber to produce polyamide. The reaction is as follows:

NH2RNH2+CICOR 'COCI- to ----CONHR NH COR' CO -

The primary amine groups on the side chains of protein macromolecules can react with acyl chloride, so graft copolymerization may occur at the same time.

　 wool ? NH2+ClCORCONH--- > wool NHCORCO NH--- +HCI

In this way, the polymer film has a strong bond with the fibers. It is reported that hexane diamine and Decyl two acyl chloride can achieve good results.

When the method is used for continuous processing, the equipment has special requirements, so industrial production is affected.

(two) pretreatment of prepolymer

The structures of commonly used prepolymers usually have three types. A polyether with branched skeleton and polyols, commonly used as polyepoxide, and polyetherethylene and butene with molecular weight of 2000~10000, usually having three functional groups. These functional groups can react with diisocyanate to form a prepolymer with active groups. The commonly used diisocyanate has toluene diisocyanate (2, 4 one and 2, 6 isomer mixture), six methylene diisocyanate or L, 4 cyclohexane diisocyanate.

Because isocyanates lose their reactivity due to their interaction with water, they are mostly processed by solvent method. The commonly used solvent is perchloroethylene or trichloroethylene. The common amount of prepolymer (solid) is L. 0~3. 5% (for wool weight). The curing reaction at room temperature takes 4~8 days to complete. If temperature, humidity, steam or catalyst are used, the reaction rate can be increased. In order to avoid using a large number of solvents as the reaction medium, the prepolymer solution can be emulsified in water. Recently, some researchers have studied the reaction of low molecular weight compounds containing active hydrogen with prepolymers, blocking the isocyanate group, and making the prepolymer stable in water. The closed reaction is reversible, and the blocked group can be removed by heating. If the blocked group can also participate in the cross-linking reaction, then the blocking or not will not affect the cross-linking reaction.

Another kind of prepolymer has a wired skeleton and has an active group at a certain distance. Most of the linear skeleton is polyacrylate or ethylene copolymer, commonly used as the inclusion group, and its content is about 5 to 10% (monomer). A prepolymer which is copolymerized by ethylene, vinyl acetate and methacryl chloride is copolymerized and 70:24:6 Zeset TP is the prepolymer. Because acyl chloride is extremely sensitive to water, organic solvents such as trichloroethylene are used as solvents. After the fabric was pretreated with a prepolymer solution, the prepolymer rapidly solidified after drying, steaming or hot pressing, forming a very thin polymer film on the fiber. If the prepolymer solution is padded into the boiling water solution, the evaporation of the solvent and polymer solidification will be completed simultaneously.

Another commonly used prepolymer is formed by reaction of polyamide with epichlorohydrin. Commercial Hercosett 57 is the reaction of polyamide containing secondary amine with adipic acid and two ethylene three amine, and then reacts with epichlorohydrin. The prepolymer can be processed by water as a medium, so it is more convenient. The technology commonly used is chlorine one Hereosett 57 for continuous processing of wool tops. The processing is basically: after the treatment of non-ionic detergent, the chlorine is treated in the condition of 1.4 to 2% of the effective chlorine (to wool weight) and pH=l.5 to 2, then dechlorination is neutralized, and then treated with prepolymer, the dosage is 2 to 0% (for wool weight), and then dried at 75~90 degrees, when the prepolymer is further reacted and solidified.

After polymer treatment Wool fabric There are two different views on the mechanism of the effect of shrinkage prevention. A kind of polymer film is considered to cover the scale surface of the wool fiber or to wrap the fibers, which reduces the directional friction effect and achieves the effect of anti felting. The other view is that the polymer mainly introduces some adhesive points between the fibers (some people call it "spot welding"), and the fibers are glued together to move freely, thus preventing the shrinkage from being felt. By observing the wool treated with Synt happret LKF by optical microscope, it is found that the fiber is completely wrapped in the polymer film. The woven fabric and knitted fabric treated with this method do have anti felting properties, but the same way can not get the effect of anti felting. The above phenomenon seems to indicate that "spot welding" is an important factor. Of course, it does not exclude the function of covering the scale. Through the observation of wool fabric treated by Synthappret LKF, it is shown that only when the polymer content on the fiber is dry 4%, "spot welding" becomes an important factor, but this quantity is much larger than the general effective anti felting requirement. In addition, after observing the fabric treated with Htercosett 57, it is considered that "spot welding" is the main factor. Therefore, these two mechanisms seem to be able to provide fibers with their own properties through their own channels.