Silicone oil usually refers to a linear polysiloxane product that remains liquid at room temperature, generally a colorless (or light yellow), odorless, non-toxic, and non-volatile liquid. Their molecular weights are not high, and they are in a fluid state at room temperature, so they are usually called silicone oils. It is generally not simply used, but made through special formulations, and is often used as an auxiliary material to produce a certain effect.

Generally speaking, there are 3 basic forms of silicone oil on the market: pure silicone oil, solution, emulsion.
1. Pure silicone oil has very strong stability, heat resistance, frost resistance, good storage performance, high flash point and high ignition point, and there are few storage and transportation problems.
2. In fact, it is often necessary to dilute the silicone oil solution. Sometimes it is desirable to add active auxiliary agents (catalysts, cross-linking agents, etc.) to the solution to facilitate storage and use. Aliphatic, aromatic or chlorinated hydrocarbons can be used as solvents as needed. Other kinds of solvents are only used under special circumstances. Generally, the concentration of polymer polysiloxane solution can only reach 35%, otherwise the viscosity is too high.
3. A large part of silicone oil or products containing silicone oil are in the form of emulsion. Compared with solvent silicone oil, it has the advantages of low price, not easy to burn, and harmless to health. Unlike solvent-based, all silicone emulsions are "oil-in-water" heterogeneous systems. Its external closed phase is an aqueous phase. The silicone oil is dispersed in the aqueous phase in very fine droplets, which can be easily diluted with water to the desired concentration. For application, the stability of this emulsion can be achieved by making the droplets as fine as possible and by the stabilizing effect of the emulsifier.

The role of silicone oil in the textile industry

Silicone oil can be used as fabric softener, lubricant, waterproofing agent, finishing agent and so on in the textile and garment industry. In order to meet the high-end demand for textiles, chemical product manufacturers are also constantly developing silicone oils that can be used in baths with various functional additives such as waterproofing agents, flame retardants, antistatic agents, and color-fixing agents. In addition, in order to improve the performance of the fabric, there are also silicone products that can be used in the same bath with dyeing, silicone oil for cotton with a cool feeling, silicone products that can improve the fabric feel, and can give fabrics excellent darkening effect and storage stability Good, does not affect color fastness, good hand feel, such as silicone-based deepening agent. In addition to the functionalization of textiles as additives in textiles, silicone products will also be applied to other fields in textiles, such as the combination of silicone and polyurethane to form the coating of the fabric; the polymerization of silicone and acrylic to form the printing of the fabric; The combination of silicon and organic fluorine forms a waterproof coating on the surface of the fabric, etc.

Silicone oils can be divided into primary products and secondary products according to their processing conditions.

The former refers to the silicone oil products before processing, including 4 categories: hydroxyl silicone oil, silicon functional silicone oil, carbon functional silicone oil and inactive modified silicone oil. Among these four categories, it is customary to call the first two types of linear silicone oils, and the latter two types of modified silicone oils.

Secondary silicone oil products refer to products such as greases, emulsions and solutions that are made of silicone oil as raw materials, mixed with thickeners, surfactants, solvents and additives, and processed through a specific process, such as silicone grease, silicone paste, Defoamer, release agent and release agent, etc.

Evolution history of domestic silicone softeners

The production and application of silicone softeners in China can be said to have gone through 4 generations:
01. The first generation is a high molecular weight polysiloxane emulsion with hydroxyl end (hydroxyl emulsion)
It is formed by emulsion polymerization of octamethylcyclotetrasiloxane (D4), water, emulsifier, catalyst and other raw materials under certain conditions.
02. The second generation is polyether modified silicone oil
It is prepared by hydrosilylation of methyl hydrogen-containing silicone oil and polyethers such as polyethylene glycol and polypropylene glycol with unsaturated bonds at the end.
03. The third generation is a polysiloxane emulsion with active groups (amino groups, epoxy groups)
The polymerization method is basically the same as that of hydroxy emulsion, the difference is that a certain amount of silane coupling agent is added to the raw material. The introduction of these amino and epoxy functional groups greatly improves the softness, smoothness, elasticity and durability of the finishing effect of the finished fabric. This type of polysiloxane emulsion with active groups uses ionic surfactant, and its emulsion is strongly cationic or anionic, and has strong selectivity and poor compatibility when compounded with other additives.
04. The fourth generation is modified silicone oil represented by amino silicone oil
It is the most representative variety of silicone softeners on the market. Usually we call aminoethyl aminopropyl polydimethylsiloxane standard amino silicone oil, and other amino substituted polysiloxanes are called modified Amino silicone oil. Due to the strong amino polarity, amino silicone oil interacts with the hydroxyl and carboxyl groups on the fiber surface, forming a very strong orientation and adsorption with the fiber, which reduces the friction coefficient between the fibers. The force starts to slide between the fibers, so that they feel soft. In recent years, organo-modified silicone oil has developed rapidly, and many organo-modified silicone oils with special properties have appeared.