What is castor oil?

Natural oil extracted from castor seeds

Castor seed which is slightly smaller than an almond is harvested from castor plants indigenous in Africa. India is now known as the biggest producer. We also import crude castor oil mostly from India. Castor oil has been used as lubricant for engine oil or a laxative for long time and is currently seen in the fields of medicine and cosmetics. Continuous and stable use of castor seeds grown as they absorb CO2 attracts attentions as one of the ways to prevent global warming.

How is castor oil made?

We meet your ideal needs with our refinement system.

When we started extraction and refinement of castor oil for the first time in Japan in 1917, we had to import castor seeds from various countries. Countries producing castor seeds, however switched to oil extraction on their own to enhance added value and it became difficult to procure castor seeds, so we decided to import crude castor oil in 1995.We are committed to refinement by ourselves so as to meet various needs from customers.

Production Process


02Castor Plant Farm




06Castor Seeds

07Oil Expression


Structure and Characteristics

Unique Biomaterial for Various Applications

Castor oil is an ester consisting of glycerin and fatty acid. Because ricinoleic acid occupies fatty acids at 90%, castor oil displays unique characteristics different from other vegetable oils. With hydroxy value and double bond in a ricinoleic acid molecule, castor oil generates a variety of chemical reactions.

Main characteristics

  • Light yellow, viscous and nondrying
  • soluble in most organic
  • solvents including ethyl alcohol
  • compatible with various resins

Composition of fatty acids

Fatty Acid Content(%)
Palmitic Acid 0.5~1.5
Stearic Acid 0.5~1.5
Oleic Acid 2.5~4.0
Linoleic Acid 4.0~5.0
Linolenic Acid 0.5~1.5
Ricinoleic Acid 87.0~91.0
Dihydroxy Acid 0.5~1.5

(From "Handbook of Oleochemistry" edited by Japan Oleochemistry Association)

Common Specification

Specific Gravity(25℃/25℃) 0.959
Refractive Index(nD20) 1.477
Viscosity(25℃) 680mPa・s
Pour Point -22℃
Flash Point 292℃
Ignition Point 449℃
Designated Combustible, Flammable Liquid

(From "Handbook of Oleochemistry" edited by Japan Oleochemical Society)

Castor oil structure

Ricinoleic Acid structure