Introduction: Silac U210 is a Single Pack Urethane Alkyd Resin based on Linseed Oil. They are polymers built up by Urethane linkages containing air drying Polyunsaturated ester groups as substitutes. In effect the modern Urethane oils are a type of Alkyd Resin in which the Dibasic Acid is replaced by a Di-Isocyanate. The Lacquers & Coatings based on Urethane varnishes are high-tech film formers, very widely used and are unequalled in properties such as toughness, hardness, durability and rapid drying. Though our “Urethane Resins” are as convenient to use as ordinary Oil modified Alkyds, being Single Pack systems and require the common solvents such as MTO and conventional driers, yet yield surface coatings which are as far superior to those possible with Alkyds or other known media. The free Isocyanate content is also Nil and hence can be used even by an unskilled worker.
Properties: The films of Urethane varnishes exhibit the following properties which are superior to those conventional media.
COMPATIBILITY: Silac U210 is compatible with all Drying oils, Long and Medium oil Alkyds, Epoxies, Ester gums, Phenolics and Maleics in all proportions and only to a limited extent in Chlorinated resins, Short oil Alkyds and Urea resins.
SOLUBILITY: Silac U210 is soluble in Mineral Turpentine Oil (M.T.O) in all proportions. They are also soluble in most of the common paint solvents like Xylene, Naphtha’s, Esters and Ketones. Wherever the ‘U' Resins have to be used with other resins of limited solubility in MTO like Epoxies & Vinyl’s etc., other suitable solvents like Toluene, Xylene or Ethyl methyl ketone should be used.
RECOMMENDED DRIERS: Since 'U' Resins are very rapid drying comparatively smaller quantity of Cobalt drier that is 1.5% to 2.00% of Cobalt as metal on the solid resin content will be adequate. However, if faster drying is required driers upto 1.50% Zirconium and 0.5 % Cobalt as metals on the resin contents can be further added, after addition of driers ageing for 24 hours in air tight containers is recommended. The Oil Modified Urethane Coatings dry (or cure) by the usual oxidation process as applicable to drying Alkyds and unsaturated oils hence require conventional driers. While the other types of Urethanes such as Moisture cured, Blocked type or the Two pack systems cure by the reaction of Isocyanate groups with Hydrogen thus require special type of drier chemicals.
MODE OF SUPPLY: Presently the 'U' Resin is supplied in 200 or 25 kg’s packing’s as 60% solids. It can be customized as per the requirements of customer.
APPLICATIONS: The unique and excellent film forming properties of 'U' Resins have made possible their use in a very wide range of applications. Some of the areas where they have shown considerable promise are: