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Silicone Emulsion

Silicone Emulsions are inert, heat stable, non-toxicity products, which suit many industrial applications where lubrication, gloss, antistatic, protective and release properties are advantageous. Silicone Emulsions can be divided into three groups depending on the type of emulsifier system used, they can be: anionic, cationic and non-ionic. Most emulsions are non-ionic as they are compatible with either of the other two systems but depending on the application, cationic or anionic emulsions can be chosen.

The viscosity and physical characteristics can be altered by using different viscosity base polymers. High perentage solids versions can be supplied as concentrates and diluted with water prior to application, this makes for more cost effective transportation

Rubber & Plastics Industry uses Release agents and lubrication Application,
Food trays & Plastics Industry uses Release agents Application,
Car Polish & Dressings Industry uses Protection, weather resistance, gloss and spreadability Application,
Household cleaners and polish Industry uses Protection, improved gloss and spreadability Application,
Textile finishing Industry uses Enhanced feel, water repellency and reduced ironing Application,
Perlite, vermiculite and clay Industry uses Water repellency Application,
Printing and paper making Industry uses Lubrication and antistatic agent Application,

ABSTRACT

Silicone polymers are a class of hybrid organic/inorganic polymers, that show desirable surface properties such a low surface energy and high flexibility, which enables even a very high molecular weight chain to achieve optimal orientation at the interface. Silicone polymers have dual characteristics, because of which they can either be used as emulsifiers or act as the continuous/dispersed phase of the emulsion in presence of surface active agents. Major characteristics of silicone emulsions are discussed in this review along with new information on silicone surfactants used for emulsification. Finally an analysis of silicone emulsification technology is presented along with their recent applications and significance to the modern day life style.

Silicone (e.g. poly(dimethyl siloxane) and derivatives) polymers are an important class of hybrid organic/ inorganic polymers that have been commercialized extensively in their liquid state. Silicones differ considerably from their organic counterparts due to their weak intermolecular attractive forces. Structurally they are characterized by 1) Si-O-Si bond angles (140°) that are larger than C-O-C bond angles (110°), 2) Si-O bond lengths (1.64 A) that are longer than C-C bonds (1.53 A), 3) a greater freedom of rotation around the Si-O bond compared to the C-C bond and 4) freely rotating methyl groups which can orient towards interfaces (11). These characteristics allow silicone molecules to present it in unique molecular conf igurat ions that al low lower interfacial energies and outstanding lubricating properties at low pressures. Silicones are water repellent, heat stable, and highly resistant to chemical attack (11). Since silicones are insoluble in both water and many hydrocarbons, a very common mode of delivering them is in the form of emulsions. The delivery of silicones in hydrocarbons or hydrocarbon continuous emulsions has gained little interest; therefore only water-continuous emulsions will be considered in this paper. Silicone emulsions typically contain water, silicone oil, stabilizing surfactants, preservatives and other additives for viscosity stabilization and freeze-thaw stability (5). The low surface tension and incompat ibi l i ty of silicones with water and many hydrocarbons pose unique problems that mak e emulsification process distinctly different from traditional hydrocarbon emulsification processes (8). Thus most surfactants that are considered suitable for emulsification of hydrocarbons and fats are not effective for silicones. Additionally, chemical modifications of silicones further complicate the emulsification technology for silicones. Although any type of surfactants could be used to develop silicone emulsions, majority of emulsions involves the use of non ionic surfactants .

Other Applications

Silicone oils and emulsions are used as lubricants and release agents in a variety of fields (28). Various silicone emulsions are used as release agents for manufacturing rubberized belts, lubricants to prevent wear and increased abrasion resistance to latex rubber, as release agents in the printing industry, as lubricants for yarn and sewing threads to eliminate friction and tension, and as finishes to improve water-repellency and scuff resistance for leather, vinyl and foam upholstery. In an interesting application silicone emulsions have been used as lubricants in peaseed protectants (28). Silicone emulsions have been employed to treat glass surfaces in order to add new advantageous properties such as the removal of a water film, lowering the wettability towards water, and increase of the tensile strength. Advantages of lowered wettability of glass by silicone treatment in the pharmaceutical area include: 1) retardation of blood coagulation; 2) complete emptying of medicines from bottles. In the drilling of oil wells, the drilling fluids used can be brine-in-oil emulsions, which must be stable at high temperatures and pressures. Calcium chloride, calcium bromide or zinc bromide are used to obtain brines with high specific gravity to improve the pressure control. These conditions require emulsifiers of high performance, which is the case for silicone-based emulsifiers (29). In a similar application silicone emulsions of lower viscosity have been used for removal of chlorinated solvents from contaminated subsurface environments (30).

Mould Release Agents

Mould release agents like silicone mould release agents, release coatings, release coating emulsions etc., are special types of lubricants that are applied to mold surfaces for assisting in the release of molded article. Certain characteristics which add to the excellent features of our Mould Release Agents are anti stick characteristics, parting agent, mold wash, mold lubricant and others.