The fatty acid of castor oil contains 90% ricinoleic acid (9-alkenyl-12 hydroxy octadecanoic acid), the hydroxyl value is 163 mgKOH/g, the hydroxyl content is 4.94%, and the molecular weight calculated by hydroxyl is 929.26. Hemp oil contains 70% trifunctionality and 30% difunctionality, and the average hydroxyl functionality is 2.7.

The polyurethane adhesive made from castor oil has good low temperature performance, hydrolysis resistance and excellent electrical insulation.

Castor oil contains a large amount of ricinoleic acid (more than 80%), so it has many unique properties:

1. Easy to dissolve in ethanol, difficult to dissolve in petroleum ether. The presence of this characteristic makes it easier to distinguish castor oil from other oils.

2. The viscosity is much higher than that of general grease, 680CPS at 25, the viscosity index is 84, and the friction coefficient is very low (0.1).

Castor oil has good fluidity. Refined castor oil can still flow at -22°C, and there is no turbidity after quenching at -50°C. It is an ideal lubricating oil for aviation and high-speed machinery and protective oil for power belts.

3. It has strong optical activity because the asymmetric carbon atom in its main fatty acid - ricinoleic acid is after the 12th position.

4. The dielectric constant is about 4.30, which is the highest among common greases.

5. The relative density and acetyl value of castor oil are greater than those of ordinary oils.

6. Castor oil hardly undergoes oxidative rancidity in the air, and has good storage stability. It is a typical non-drying liquid oil.