Castor oil is increasingly finding application in the manufacture of polyurethane foams. The polyurethane is produced from polyols based on castor oil.

Polyols can be reacted with diisocyanates to make polyurethanes.

There are a limited number of naturally occurring vegetable oils (triglycerides) which contain the unreacted hydroxyl groups that account for both the name and important reactivity of these polyols. Castor oil is the only commercially-available natural oil polyol that is produced directly from a plant source: all other natural oil polyols require chemical modification of the oils directly available from plants.

Features of Castor Oil Based Polyurethane

·         Superior to PPG (Polypropylene Glycol) or polyester in water and hydrolysis resistance

·         Superior to PPG or polyester in insulation

·         Lower viscosity than Polybutadiene or Polyester

·         One of the most challenging issues of polyurethane flooring is heat and humidity. The urethane produced from castor oil is stable under high heat and humidity.

A Typical Polyurethane Formulation

Polyurethane –Applications

Polyurethane is ultimately used to make elastomeric shoe soles, fibers, foam insulation for appliances Castor oil by itself has been used in making a variety of polyurethane products, ranging from coatings to foams, and the use of castor oil derivatives continues to be an area of active development. Castor oil derivatized with propylene oxide makes polyurethane foam for mattresses., adhesives, mattresses, automotive seats and so on.

Prominent Companies and Efforts

·         In September 2013, Jayant Agro Organics Ltd, an Indian oleochemical company, have entered into a joint venture agreement with two Japanese firms – Mitsui Chemicals Inc and Itoh Oil Chemicals Co Ltd – for manufacturing castor oil based polyols.

·         In September 2011, Ford and BASF have teamed up to develop a sustainable, plant-sourced castor oil-based polyurethane foam product for the 2012 Ford Focus instrument panel.

·         ACTEGA Rhenania (www.actega.com) has developed a novel series of solvent-free polyurethane adhesives for laminates to be used in packaging. Raw material involved in polyurethane is castor oil derivative.

·         In Feb 2009, Keetsa, a San Francisco retailer, manufactured mattresses using  polyurethane foam made from castor oil. The product called as Biofoam, partially utilized castor oil (The other 88 percent, though, is still petroleum-based)

·         BASF produces Lupranol Balance, a polyol made up of 31% castor oil by weight. BASF’s European polyurethane (PU or PUR) subsidiary, Elastogran, produces it for the synthesis of soft PU foams used in mattresses.

·         Alberdingk Boley,  a German based company, produces castor oil based aliphatic polyurethane dispersions. To know more about the product, click - http://www.alberdingkusa.com/products/technical-data/cat2/renewable-polyurethanes.html

Research Data in Castor oil based Polyurethanes

·         In a recent research study conducted in France, ricinoleic acid from castor oil can serve as a substrate for the synthesis of intermediate monomers, 10-hydroxy-9-methoxyoctadecanoyl azide/9-hydroxy-10-methoxyoctadecanoyl azide (HMODAz), 12-hydroxy-9-cis-octadecenoyl azide (HODEAz) and methyl-N-11-hydroxy-9-cis-heptadecen carbamate (MHHDC) which will subsequently enter into a AB type- self condensation reaction for synthesis of bio-based polyurethanes.

·         Several Brazilian research works have shown that new materials, based on polyurethane resins derived from castor oil, have had great success in the medical field. This could in fact be expected because of their stable physical and chemical properties. In this work, using the same fabrication techniques, thin films and circular plates of 1-2 mm thickness, of these resins were made and electrically characterized. Tests for a.c. electrical breakdown, permittivity, D.C. insulation resistance and dissipation factor show that these materials are very good insulators. Internal insulators and conductor covers are among their main applications. Their mechanical properties are also presented and discussed – (Source: Gonzaga, D.P.; Murakami, C.R.; Chierice, G.O.; Altafim, R.A.C. Electrical Insulation, 1998. Conference Record of the 1998 IEEE International Symposium on Volume 1, Issue , 7-10 Jun 1998 Page(s):181 - 185 vol.1)