Brown factice

Factice is produced from fatty oils such as linseed oil, castor oil, soybean oil, or rape seed oil. To obtain brown factice, the oil is heated with sulfur to 130-160 C for 6- 8 h. This vulcanization gives a soft, crumbly, elastic product with 5%-20% sulfur. White factice is obtained by vulcanization of the oil with S2CI2 at room temperature. It contains 15%-20% sulfur and is not elastic. Both types of factice are used as cheap bulking materials in rubber articles, and improve the calendering processing of natural rubber. 

The above discussion relates to the "drying of oils by oxygen. Materials like natural rubber (see Natural Polyisoprenes section) are vulcanized with sulfur. The unsaturated oils can be made to undergo a similar set of reactions (48). Brown factice is made by first blowing a drying oil, then reacting it with 5-30% of sulfur at 250-350°F for 1-2 hours. 

The choice of vulcanizing agents has been much the same for the past 150 years with the exception of the use of an isocyanate cross-linker added during the last 50-60 years. Elemental sulfur (brown factice), sulfur chloride (white factice), hydrogen sulfide (light yeUow/translucent factice), isocyanate, and peroxide (very white/hard/translucent factice) comprise the main types employed for vulcanizing vegetable oils. 

Two main grades of factice exist, namely brown , which is usually vulcanized by elemental sulphur, and white , which is usually vulcanized by sulphur chloride. 

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