The use of non-woven fabrics as automotive interior decoration materials is the current international development trend. Because of its low cost, strong adaptability, high strength, and light weight, it is widely used in the automotive industry.
However, many non-woven fabrics for automobiles require water-repellent finishing, such as automobile carpets. This kind of carpets are generally molded by molding and consist of three to four layers of different materials. The outer surface layer is made of carpets with water and oil repellent, flame retardant and antistatic treatments. The roof, door trim, wall protection, and Door and window sealing strips generally have to be finished with water and oil repellent. However, the traditional water-repellent nonwovens in the market today are obtained by applying a water-repellent finishing agent in the post-finishing stage. Although the water-repellent effect has been improved, its stability has not been ideal.
In response to this situation, researchers from the materials department of the Lower Rhine University of Technology in Germany proposed the "silicone water-repellent finishing technology." According to the published information, it can be seen that after the silicone water repellent finishing, a layer of polymethylhydrosiloxane emulsion film will be covered on the surface of the nonwoven fabric, and its oxygen atoms point to the surface of the fiber, while the methyl It is oriented and arranged away from the fiber surface. Researchers have found that the proper orientation of the silicone polymer on the fiber surface is a necessary condition for its water repellency. In general, water repellency will increase with the growth of the carbon chain.
In addition to being condensed with each other into a film, polymethylhydrosiloxane can also form hydrogen bonds with the hydroxyl groups on the fiber surface, so that the hydrophobic methyl groups are arranged densely and oriented on the fiber surface to obtain satisfactory water repellency, and Has a certain washable effect. Researchers pointed out that polymethylhydrosiloxane is best kept in emulsion form. Therefore, the choice of emulsifier is very important in the water-repellent finishing of silicone. After verification, it is found that the temporary composite cationic emulsifier can effectively convert the polymethylhydrosiloxane into a stable emulsion, and it can also be decomposed during the finishing and baking process, which better solves the emulsion stability and water repellency The contradiction between.
Silicone water-repellent finishing technology is still in the laboratory stage, but the key experimental data is relatively complete: the best mixing ratio of polymethylhydrosiloxane and emulsifier is 3:7, and the drying temperature should not be lower than 150℃ , The water repellent effect is the best. It is understood that a German automotive manufacturer has cooperated with Lower Rhine University for experimental production.
In addition, Japan’s Mitsubishi Heavy Industries Co., Ltd. recently developed a high-tech resin with waterproof and breathable functions. As long as this liquid material called shape memory polymer is applied to the surface of the fabric, the fabric will not be permeable, but moisture can still be maintained. From the inside out, it is very suitable for making functional clothing such as raincoats. The waterproof and breathable function of the shape memory polymer is similar to that of human sweat pores, and it is very promising.