Silicone Emulsion

Apr 23, 2020

The silicone oil R is CH3, oh; R & acute;, CH3, h, etc. The oil content is generally 20% - 30%. PH 6-8. Centrifugal stability (3000r / min) 15-30min. The surface tension is small and the contact angle to water is large. Heat resistant, antioxidant. The emulsion was polymerized by eight methyl ring four siloxane in the presence of anionic surfactants such as twelve alkyl sulfonate or cationic surfactant such as sixteen alkyl three methyl ammonium bromide and catalyst. It is a kind of textile chemical finishing agent with excellent performance. It is often used for soft elastic and smooth finishing, silk like finishing, wool like finishing, water repellent and waterproof finishing, etc. it can be used alone or mixed with other finishing agents. The fabric treated with it can get comfortable, stylized, high-grade and functional quality effect.
Product properties
Silicone emulsion (referred to as silicone milk) is an oil in water emulsion consisting of silicone oil, water and surfactant.
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 premixed silicone oil, emulsifier and thickening agent, then gradually added water to mix it up, and then rubbed it repeatedly in the colloid mill until the desired emulsion was obtained.
Silicone oil emulsion defoamer is the most widely used and defoaming agent 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 sooner or later than the scope of its use, and it will become inefficient or ineffective (the amount of silicone oil emulsion, generally 10~10Oppm of the foaming liquid weight). Of course, there are also less than 10 ppm and more than 100 ppm in special cases. The most 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 power is greatly improved; Organosilicon polyether copolymerization 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, such a molecule has a large polarity, as a defoamer, its spreading coefficient is large, and it can be used in foaming medium It is a new type of high efficient defoamer with uniform dispersion and high defoaming efficiency. 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.