Knowledge analysis of silicone oil and low hydrogen silicone oil

Silicone oil is a kind of polysiloxane with different degree of polymerization chain structure. It is made of dimethyldichlorosilane by hydrolysis with water to produce primary polycondensation ring. The ring body is cracked and rectified to produce low ring body. Then the ring body, head sealing agent and catalyst are put together for polycondensation to obtain a variety of mixtures with different degrees of polymerization. After the low boiling matter is removed by vacuum distillation, silicone oil can be produced.

Commonly used silicone oil, the organic groups are all methyl, called methyl silicone oil. Other organic groups can also be used to replace some methyl groups in order to improve some properties of silicone oil and apply to various purposes. Other common groups are hydrogen, ethyl, phenyl, chlorophenyl, trifluoropropyl, etc. In recent years, organic modified silicone oil has been developed rapidly, and there are many organic modified silicone oil with special properties.


Jiangxi Huahao Chemical Co., Ltd.

Silicone oil is generally colorless (or light yellow), tasteless, non-toxic, non-volatile liquid. Silicone oil is insoluble in water, methanol, glycol and - ethoxyethanol. It is miscible with benzene, dimethyl ether, methyl ethyl ketone, carbon tetrachloride or kerosene. It is slightly soluble in acetone, dioxane, ethanol and alcohol. It has small vapor pressure, high flash point and ignition point, and low freezing point. With the different number of chain segments n, the molecular weight increases and the viscosity also increases. There are various viscosities for fixing the silicone oil, ranging from 0.65 centistokes to millions of centistokes. If low viscosity silicone oil is to be prepared, acid clay can be used as catalyst and polymerized at 180 ℃, or sulfuric acid can be used as catalyst and polymerized at low temperature to produce high viscosity silicone oil or viscous substance.

According to the chemical structure, silicone oil can be divided into methyl silicone oil, ethyl silicone oil, phenyl silicone oil, methyl hydrosilicone oil, methyl phenylsilicone oil, methyl chlorophenyl silicone oil, methyl ethoxy silicone oil, methyl trifluoropyl silicone oil, methyl vinyl silicone oil, methyl hydroxysilicone oil, ethyl hydrosilicone oil, hydroxyhydrosilicone oil, cyanogen silicone oil, low hydrosilicone oil, etc.; from the purpose, damping silicone oil is available. Oil, diffusion pump silicone oil, hydraulic oil, insulating oil, heat transfer oil, brake oil, etc.

Silicone oil has excellent heat resistance, electrical insulation, weather resistance, hydrophobicity, physiological inertia and small surface tension, in addition to low viscosity temperature coefficient, high compression resistance) some varieties also have radiation resistance.

Jiangxi Huahao Chemical Co., Ltd. is located in Xinghuo Industrial Park. It was founded in November 2011 and covers an area of more than 30 mu. In 2014, phase I Project (4500t / a silicone series products) was put into operation and accepted. The main products are: hydroxy silicone oil, dimethylsilicone oil, low hydrogen silicone oil, polyether modified silicone oil and 107 rubber. In 2017, it enriched the downstream organic products, increased vinyl silicone oil, amino silicone oil and silanes, including methyltrimethoxysilane, methyltriethoxysilane and methylsilicic acid, and also improved the varieties of hydrogenated silicone oil, with a single side hydrogen in the early stage, and increased end hydrogen and other hydrogenated structural products. At present, high boiling silicone oil which can partially replace methyl silicone oil is being studied. Started to operate in phase III project in 2018, the products include heptamethicone, polyether modified silicone oil, silazane, silicon ether, dimethyldiethoxysilane and other products

Silicone Emulsion

Silicone emulsion is a form of silicone oil. The following is introduced from two aspects: silicone oil softener and silicone oil emulsion defoamer.

I. silicone oil fabric softener

Silicone emulsion is mainly used as softener for silicone oil fabrics. The first generation of silicone fabric finishing agent is a mechanical mixture of dimethylsilicone oil and hydrosilicone oil (and its derivatives). The two generation of organosilicon fabric finishing agent is hydroxyl terminated poly two methyl siloxane emulsion. It is made by emulsion polymerization of eight methyl ring four siloxane monomer, water, emulsifier, catalyst and other raw materials under certain conditions. Because polymerization and emulsification are completed in one step, it has the advantages of short working hours, high working efficiency, simple equipment and convenient operation. The emulsion obtained is very stable, and the particles are very uniform. The active polymer (hydroxyl) at both ends of the polymer can be further reacted to form a film, which is conducive to improving the application effect of emulsion, which is not enough for mechanical emulsified silicone oil.

Hydroxyl silicone oil emulsion can be divided into several types of emulsion, such as cation, anion, nonionic and compound ions, according to the different surfactants used.

1. cationic hydroxyl silicone oil emulsion

The emulsifier used in cationic emulsion polymerization is usually quaternary amine salt (octadecyltrimethyl ammonium chloride reported in Foreign Literature), and the catalyst is ammonium hydroxide. Cationic hydroxyl milk can be used in various textiles after finishing. It has the properties of improving fabric handle, improving fabric elasticity and smoothness. It has another unique advantage: the ideal waterproof agent for fabrics, it is compatible with methyl hydrogen silicone oil emulsion, waterproofing and waterproof durability. It can be used as waterproofing agent for polyester cover canvas and waterproof agent for polyester card cloth. And so on.

2. anionic hydroxyl silicone oil emulsion

The anionic hydroxyl milk is characterized by its compatibility in fabric finishing agent, and the emulsion is very stable. 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 bleaching oil, while anionic hydroxy emulsion can avoid this disadvantage, so it is more popular with users and widely used.

3. compound ionic hydroxyl silicone oil emulsion

Although cationic hydroxyapatite is an excellent fabric softener, this emulsion is not resistant to hard water and can not be used with dimethylolyl two hydroxyurea urea resin.

Although cationic hydroxyapatite is an excellent fabric softener, this emulsion is not resistant to hard water, and can not be used in the same bath with dimethoxylated two hydroxyvinyl urea resin (2D) resin, catalyst magnesium chloride and anionic whitening agent. In addition, because of the poor stability of the emulsion, silicone polymers are easily separated from the emulsion and float on the liquid surface, commonly known as "bleaching oil". If the cationic and non-ionic emulsifiers are used in the emulsion polymerization, the shortcomings of the cationic emulsifier for preparing hydroxyl silicone oil emulsion can be overcome. The prepared silicone emulsion can withstand hard water, and can be used in the same bath with 2D resin, magnesium chloride and whitening agent VBL, and has good heat resistance and freezing resistance.

4. non ionic hydroxyl silicone oil emulsion

Nonionic hydroxy milk has better adaptability and stability than isolated hydroxy milk, so many countries have made great efforts to study nonionic hydroxy milk. For example, UltrateX FSA, a new product made in Switzerland, is a non-ionic emulsion with a molecular weight of more than 200 thousand and a hydroxyl head of two methylsiloxane. It is a step forward than the Dc-1111 anionic hydroxyapatite emulsion in the United States.

5. Organosilicon finishing agent with other active groups

In order to meet the needs of advanced finishing of all kinds of fabrics, improve the anti oil, anti-static and hydrophilic properties of silicone finishing 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 group, amide group, ester group, cyano group, carboxyl group, epoxy group, etc. The introduction of these groups makes organosilicon fabric finishing agent have special effects, for example, the introduction of amino group into organosilicon molecule is suitable for preshrunk and soft finishing of wool; the introduction of amide group is suitable for antifouling finishing, and the softness is greatly improved: the introduction of cyano group has good oil resistance, and the anti-static effect of the copolymer of polyoxyethylene ether and organosilicon is good; the organofluorine modified organosilicon has oil repellency. Anti pollution, anti-static, water repellent and many other advantages.

Two. Silicone oil emulsion defoamer.

Silicone oil emulsion defoamer is generally oil in water (O/W) emulsion, that is, water is a continuous phase, silicone oil is a discontinuous phase. It is pre mixed with silicone oil, emulsifier and thickening agent, and then gradually add water to mix, repeatedly grinding in the colloid mill until the desired emulsion is obtained.

Silicone oil emulsion defoamer is a defoaming agent widely used in silicone defoamer. It can be widely used as defoamer in aqueous system. When used, the emulsion can be added directly to the foaming system, and good defoaming effect can be obtained. In order to improve the defoaming effect of emulsion and the accuracy of measurement, it is generally not used directly more than 10% of concentrated silicone oil emulsion: first, it is diluted to 10% or less with cold water or directly with foaming solution. Taboo should be diluted with overheated or undercooled liquid, otherwise it will cause emulsion demulsification. The stability of emulsion will become worse after dilution, and layering (oil bleaching) phenomenon may occur in storage process, that is, demulsification. Therefore, the diluted emulsion should be used as soon as possible. If necessary, thickeners can be added to improve the stability of the emulsion. For batch operation, silicone oil emulsion can be added either before the system runs or in batches. For continuous operation, silicone oil emulsion should be added continuously or intermittently in the appropriate parts of the system.

In the use of emulsion defoamers, the temperature and acid and alkaline conditions of the foaming system should be taken into consideration. Because the silicone oil emulsion is more delicate, its emulsion will be demulsified earlier, and it will become inefficient or ineffective. The amount of silicone oil emulsion is generally 10 to 10Oppm of the weight of the foaming liquid (according to the silicone oil meter). Of course, there are also less than 10 ppm and more than 100 ppm in special cases. The suitable dosage is mainly determined by experiments.

Generally, silicone oil emulsion defoamer is mostly oil in water. According to the different types of silicone oil, silicone oil emulsion defoamer has the following types:

1. silicone oil emulsion based on two methyl silicone oil

This kind of defoamer is made up of dimethylsilicone oil, emulsifier and water. It can be widely used in fermentation, food, papermaking, fiber, pharmacy, synthetic resin and so on.

2. silicone oil emulsion based on methyl ethoxy silicone oil

This kind of defoamer is made of methyl ethoxy silicone oil and its compounding agent.

3. silicone oil emulsion based on ethyl silicone oil

In recent years, organosilicon defoamer is developing towards block copolymerization (or graft copolymerization) of organosilicon polyether. This kind of defoamer has the characteristics of both organosilicon and polyether, so the defoaming force is greatly improved; organosilicon polyether copolymer defoamer, also known as self emulsifying organosilicon defoamer, is a hydrophilic ethylene oxide chain or ethylene oxide propylene oxide chain block (or graft) in the organosilicon molecular chain, so that the hydrophobic siloxane part is combined with the hydrophilic polyether. As a defoamer, such a molecule has a large spreading coefficient, can disperse evenly in the foaming medium, and has a high defoamer efficiency. It is a new type of high-efficiency defoamer. The emulsifying effect of self emulsifying silicone oil without emulsifier is quite satisfactory for some systems. It is especially suitable for those unsuitable for general silicone oil emulsion and general silicone oil emulsion.

Post time: Sep-24-2022