Silicone oil fabric softening finishing agent
Source:iotachem.com
PostTime:2024-07-26 15:28:19
Silicone emulsion is mainly used as a silicone fabric softening agent. The first generation of silicone fabric finishing agents is a mechanical mixture of dimethyl silicone oil and hydrogen silicone oil (and its derivatives). The second generation of silicone fabric finishing agents is a hydroxyl-terminated polydimethylsiloxane emulsion, which is formed by emulsion polymerization of octamethylcyclotetrasiloxane monomer, water, emulsifier, catalyst and other raw materials under certain conditions. Since polymerization and emulsification are completed in one step, it has the advantages of short working time, high efficiency, simple equipment and convenient operation. The obtained emulsion is very stable, the particles are very uniform, and the obtained polymer has active groups (hydroxyl groups) at both ends, which can further react to form a film, which is conducive to improving the application effect of the emulsion, which is beyond the reach of mechanical emulsified silicone oil.
Hydroxy silicone oil emulsions can be divided into several types of emulsions, such as cationic, anionic, nonionic, and complex ionic, according to the different surfactants used.
1. Cationic hydroxy silicone oil emulsion
The emulsifier used in cationic hydroxy emulsion polymerization is generally quaternary ammonium salts (octadecyl trimethyl ammonium chloride is reported in foreign literature), and the catalyst is ammonium hydroxide. Cationic hydroxy emulsion can be used for finishing of various textiles, which has the advantages of improving the feel of fabrics, increasing the elasticity of fabrics, and enhancing the smoothness and crispness of fabrics; its other unique advantage is that it is an ideal waterproof agent for fabrics. When used in combination with methyl hydrogen silicone oil emulsion, the waterproof performance and waterproof durability can reach a very high level. It can be used as a waterproof agent for vinylon awning canvas and polyester fabric.
2. Anionic hydroxy silicone oil emulsion
The characteristics of anionic hydroxy emulsion are good compatibility in fabric finishing agents and very stable emulsions. In particular, most of the auxiliaries in textile printing and dyeing are anionic. If cationic hydroxy emulsion is used, it is easy to cause demulsification and oil bleaching. Anionic hydroxy emulsion can avoid this drawback, so it is more popular with users and has a wide range of uses.
3. Composite ionic hydroxy silicone oil emulsion
Although cationic hydroxy emulsion is an excellent fabric softening finishing agent, it is not resistant to hard water and cannot be used in the same bath with dihydroxymethyl dihydroxyethylene urea resin (2D) resin, catalyst magnesium chloride and anionic brightener, so it has certain limitations in use. In addition, due to the poor stability of the emulsion, the silicone polymer is easily separated from the emulsion and floats on the liquid surface, commonly known as "floating oil". If cationic and non-ionic emulsifiers are compounded during the emulsion polymerization process, the shortcomings of the preparation of hydroxy silicone oil emulsion with cationic emulsifiers can be overcome. The prepared silicone emulsion is resistant to hard water, can be used simultaneously with 2D resin, magnesium chloride and brightener VBL, and has good heat resistance and freezing resistance.
4. Nonionic hydroxy silicone oil emulsion
Non-ionic hydroxy emulsions are more adaptable and stable than ionic hydroxy emulsions, so many countries have made great efforts to study non-ionic hydroxy emulsions. For example, the new product Ultrace FSA produced by Ciba-Geigy of Switzerland is a hydroxyl-capped polydimethylsiloxane emulsion with a molecular weight of more than 200,000, which is a step forward compared to the DC-1111 anionic hydroxy emulsion of Dow Corning of the United States.
5. Silicone finishing agents with other active groups
In order to meet the needs of advanced finishing of various fabrics, improve the anti-oil, anti-static and hydrophilic properties of silicone-finished fabrics, and make chemical fiber fabrics have many advantages of natural fabrics, silicone workers have studied the introduction of other active groups such as amino, amide, ester, cyano, carboxyl, epoxy, etc. on silicone molecules. The introduction of these groups makes silicone fabric finishing agents have special effects. For example, the introduction of amino groups into silicone molecules is suitable for shrinkage prevention and softening finishing of wool fabrics; the introduction of amide groups is suitable for anti-fouling finishing, and the softness is also greatly improved; the introduction of cyano groups has good oil resistance, and the copolymer of polyoxyethylene ether and silicone has good anti-static effect; organic fluorine-modified silicone has many advantages such as oil repellency, anti-fouling, anti-static, and water repellency.
