Silicone Solvent

Novel Solvent and Dispersant Systems for Fluoropolymers and Silicones  

Prior to their current phase-out, chlorofluorocarbons (CFCs) were widely used as processing solvents for various materials. CFCs were well suited for many medical applications owing to their high solvency, nonflammability, good materials compatibility, and low toxicity. The uses for CFCs include a silicone deposition solvent, a fluoropolymer dispersion liquid, and processing solvents. However, the Montreal Protocol phase-out of ozone-depleting substances has required that alternative dispersants and solvents be found. Limitations of most available alternatives include flammability, low volatility, poor solvency, and poor materials compatibility. 

MARK W. GRENFELL 3M Company, St. Paul, Minnesota 55144-1000 Fluoropolymers 2 Properties, edited by Hougham et al. Plenum Press, New York, 1999. 

This chapter will discuss the advantageous properties of PFCs for use as carrier solvents and dispersants, and several application examples will be illustrated to demonstrate their efficacious use. 

Perfluorocarbons are a class of organic compounds in which all of the hydrogen atoms are replaced with fluorine atoms. They possess unicpie properties that make them very useful as dispersants, carrier solvents, and processing solvent additives. Their lack of chlorine or bromine atoms results in zero-ozone-depletion 

One useful blend currently being employed as a very effective silicone solvent on an industrial scale is a mixture of 80 vol % hydrocarbon heptane and 20 vol % perfluoropentane, called 1.-12808 (see Table 6.7). 1.-12808 is useful for applying silicone lubricants to numerous medical devices, such as needles, IV spikes, blood filters, and catheters. This mixture shows no flash point and no explosion limits in air. The presence of the more volatile PFC, relative to the HC, 

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Chemical compounds manufactured at petrochemical plants include methanol, formaldehyde, and halogenated hydrocarbons. Formaldehyde is used in the manufacture of plastic resins, including phenolic, urea, and melamine resins. Halogenated hydrocarbons are used in the manufacture of silicone, solvents, refrigerants, and degreasing agents. 

Exemplary water-repellent treatments for masonry surfaces include metal stearates, oils, waxes, acrylates (both polymers and monomers), silicones (solvent-based and emulsion), siliconates, silanes and, fluorochemicals. In contrast, to waterproofing coatings, water-repellent coatings, because they are permeable to water vapor, do not trap moisture and, therefore they can reduce spalling. In addition most water-repellent coatings do not alter the appearance of a porous masonry. 

Table II. FT-lR Analysis of Low Volatiles from Cured RTV Silicone Solvent Extractables...

Yeoceal Water Repellent [Wacker Silicones] Solvent-free, all weather sealer. 

Hydrophobic pore liner Silicones Solvented Loss of solvent and reaction... 

Silicone Solvents—poor Excellent Excellent Good Very low Fair to excellent. Cured by heat Airdiy(RTV) Snrav. brash, dip Heat-resistant coating fiir... 

Within solvent release type thermosetting sealants, there are Neoprene, hutadiene-styrene, chlorosulfonated polyethylene, EPDM, and silicones. Solvent release types constitute the largest variety of sealants and are composed of three parts (1) the liquid portion of the compound which is the basic non-volatile polymer/elastomeric vehicle, (2) the pigment component, and a (3) solvent or thinner component used to ease the process and to control the thickness. The sealant is cured and its required viscosity is controlled by the evaporation of solvent. 

Silstrip silicone solvent/remover Penn-White... 

In the adhesives, sealants and coatings market, Kraton SBC products primarily compete with acrylics, silicones, solvent-based... 

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