Varnish is a transparent, hard, protective finish or film primarily used in wood finishing but also for other materials. Varnish is traditionally a combination of a drying oil, a resin, and a thinner or solvent. Varnish has little or no color, is transparent, and has no added pigment, as opposed to paints or wood stains, which contain pigment and generally range from opaque to translucent. Early varnishes were developed by mixing resin—pine sap, for example—with a solvent and applying them with a brush to get the golden and hardened effect as seen in today's varnishes.
Components of classic varnishes-drying oil, resin, solvent.
The two main types of natural varnishes are spirit varnish (alcohol-based) and turpentine or petroleum based varnish.
Spirit varnishes are solutions of gum resins, like dammar and lac, in volatile liquids such as turpentine, mineral spirits, alcohol, benzoyl, etc., produced commonly with and without the application of heat.
Varnish has been known from antiquity; the Egyptians coated mummy cases with a paste like form made of soft resins dissolved in oil and applied when warm. Natural varnishes have largely been replaced by varnishes containing synthetic resins, chief among which are the alkyd, polyurethane, phenolic, vinyl, and epoxy resins.
At end-2012 and varnishes market in India surpasses Rs479.4 billion, supported by stable demand for home paints and increasing consumer interest in innovative and premium products. Imports’ value maintains steady growth with 23% CAGR. Global demand for varnishes is forecast to expand 4.7% p.a. between 2014 and 2018. Global Research & Data Services, the expansion of the global paint and varnish industry is forecast to reach 4.7% p.a. between 2007 and 2013 the market increased with an average annual growth of 4.2%. Currently, non-aqueous polymer (other than polyester, vinyl and acrylic polymer) based paints and varnishes account for 36.6% of the global market.
Further information:
Spirit Varnishes Technology Handbook (with Testing and Analysis) describes the detailed information on the subject. The major contents of this book are-Characteristics of Spirit Varnishes Solvents, Source, preparation and uses of solvents, The Oleoresinous conifers, Distillation of Turpentine, Chemistry and distillation of rosin, Rosin Spirit Rosin Oil, Wood turpentine, wood tar and wood creosotes, Dragon blood, Elemi, Gamboge, Balsam, Java, Japanese, Chinese and Burmese lacquers, Shellac, Colors and Stains, Principles and Practice of Spirit, Copal and damar spirit varnishes, Rosin Spirit, Sandarach, Shellac Spirit Varnishes and Enamels, The determination of resins and solvents in Spirit Varnishes.etc.
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