Properties: The films of Urethane varnishes exhibit the following properties which are superior to those conventional media.
COMPATABILITY: 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 0.5% to 1.0% of Cobalt as metal on the solid resin content will be adequate. However, if faster drying is required driers upto 1.5% Zirconium and 0.5 % Cobalt as metals on the resin contents can be 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% & 80% solids. It can be customized as per the requirements of customer. We can also supply the above ‘U’ Resins up to 80% solids only and packed in MS Drums with 200 Kg’s net packing.
COMPARATIVE FILM PROPERTIES: 'U' Resins represent the latest high technology development in the surface coatings field, they have made possible to manufacture superior grade enamels which are very popular abroad both for decorative and Industrial applications. Their performance is usually compared with Alkyds which are widely used by the Paint Industry. The following table presents the comparative advantages and disadvantages of 'U' Resins with alkyd resin varnishes, Cardanol based Styrenated Phenolic resin (i.e. Silex 55) is also included as a reference point being our very popular resin. The comparison is made between the films of varnishes of the above with 30% solids and MTO as solvent
SUPERIORITY OF OIL MODIFIED POLYURETHANES OVER OTHER P.U. SYSTEMS: It can be seen from the following table that all other P.U. Systems require special costly thinners. Special techniques for pigmentation, costly driers and specially trained labour for handling paints based on them as they contain free N.C.O. They also have limited pot life. The only advantage which they have over modified PU Systems is better hardness of the film and better chemical resistance in some cases.
APPLICATIONS: Very Fast drying paints with high scratch hardness, high Gloss, Excellent water chemical and Abrassion Resistance, Wood Lacquers and high class insulating varnishes etc,.