Non-drying castor oil is converted into a drying oil when the hydroxyl group and adjacent hydrogen are removed from each ricinoleic acid chain. An additional double bond is created, resulting in two double bonds on each chain. The result of this process is a light colored, odorless, drying oil known as dehydrated castor oil.Dehydrated castor oil is a castor oil from which approximately 5% of the chemically combined water has been removed. Heating the oil in the presence of catalysts such as clays and metal oxides, phosphoric acid, and sulfuric acid, is where dehydration is carried out Main fatty acid composition of DCO is octa decadienoic acid. The most characteristic aspect is it contains conjugated linoleic acid .Therefore it has drying properties similar to those of Tung oil. DCO dries quicker than linseed oil. Paints incorporating DCO is superior in non-yellowing property, adhesion to metals, chemical resistance, water-proof, flexibility, hardness and gloss.DCO can be converted to dehydrated castor fatty acid by hydrolysis and distillation. This (dehydrated castor fatty acid) is used in the manufacture of alkyd resins, coatings, appliance finishes, primers and inks.
In commercial manufacture of dehydrated castor oil, the aim is to produce the most valuable material for use as a drying oil. Dehydrated castor oil is now recognized as an individual drying oil with its own characteristic properties and advantages. The drying oils owe their value as raw materials for decorative and protective coatings to their ability to polymerize or "dry" after they have been applied to a surface to form tough, adherent, impervious, and abrasion resistance films. The advantages claimed in surface coating applications include excellent odor and heat bleachability, good drying properties, more uniform polymer structure, and lack of after-yellowing.
|Parameters||Dehydrated Castor Oil (D.C.O.)||DCO Stand Oil|
|DCO Commercial||DCO PALE||DCO EXTRA PALE|
|Appearance||Reddish yellow Clear, liquid.||Pale yellow Clear, liquid||Pale yellow Clear, liquid||Yellowish, Viscous, Clear liquid.|
|Relative density |
|Refractive index |
|Refractive index |
|Viscosity on Brookfeild |
@ 20? C
|1.8-2.0 Poise||1.7-2.0 Poise||1.6-1.9 Poise||10-250 Poise|
|viscosity (25?C)||1,6 - 2,8||1,6 - 2,8||1,6 - 2,8|
|Viscosity (Gardner scale)||G ? I||G ? I||G ? I|
|Acid value||6.00 Max.||5.00 Max.||4.00 Max.||25.00 Max.|
|Iodine value(Wijs)||127 Min.||127 Min.||128 Min.||100-200|
|Hydroxyl value?? mg KOH/g||25 Max.||23 Max.||22 Max.||15.00 Max.|
|Saponification value mg KOH/g||192-200||192-200||192-200||192-200|
|specific gravity (15?C)||0,982 - 0,933||0,982-0,933||0,982 -0,933|
|Color, Gardner||8 G Max.||7 G Max.||4 G Max.||8 G Max.|
|Color, Lovibond 1?cell (Y+5R)||40 Unit Max.||15 Unit Max.||10 Unit Max||10 Max.|
|Uses & Applications|
As superior drying oils the Dehydrated Castor Oil (D.C.O.) may be used as primary binders to upgrade house paints, enamels, caulks, sealants and inks. In cooked varnishes they combine with all the Basic resins, Rosin, Rosin-esters, Hydrocarbons and phenolic to produce clear varnishes and vehicles for pigmented coatings. In Varnishes, Alkyds and complex copolymers they provide impart resistance, Flexibility, Gloss, Chemical resistance, Adhesion, Flow and leveling.
The major applications are in high quality durable vehicles. These include Corrosion resistant coating, Traffic paints, Wire enamels, Can coating, Aluminum paints, Primers and application finishes.
D.C.O. Stand oil blended with hydrocarbon or phenolic resins produce excellent vehicle for aluminum pigments. Topcoats and primers have demonstrated superior weathering, water resistance and anti-corrosive properties. Storage test on paint prepared from these vehicles have shown excellent retention of leafing properties and no viscosity change after one year.
D.C.O. Stand oil is also used to modify alkyds. It is used in the preparation of alkyd resins to increase the oil length. Alkyds prepared with copolymer D.C.O. Stand oil impart batter flexibility, impact resistance toughness without adversely affecting water and chemical resistance.
Different grades of DCO are available on request