Castor Oil Derivative Polyols

By adding ethylene glycol, glycerol, trimethylolpropane, pentaerythritol, sorbitol, or even low molecular weight polyether polyols for alcoholysis and transesterification, castor oil derivatives with different hydroxyl values, functionalities, and molecular weights can be obtained. The transesterification reaction temperature is generally 200-220°C, with a catalyst added to promote the alcoholysis. For example, the alcoholysis (transesterification) reaction of castor oil with glycerol can yield glycerol monoricinoleate and glycerol diricinoleate. The castor oil derivatives obtained from transesterification not only increase the hydroxyl value and functionality but also improve the reactivity of the product due to the increased content of primary hydroxyl groups. These castor oil alcoholysis product polyols have been widely used in coatings and can be used in rigid and semi-rigid polyurethane foams.

Vertellus Performance Materials Inc. specializes in supplying Polycin and Caspol series of castor oil-based oligomer polyols for polyurethane coatings, adhesives, sealants, and elastomers, offering excellent adhesion, moisture resistance, water resistance, and chemical resistance. The low-viscosity Polycin and Caspol series products exhibit the typical flow and leveling advantages of castor oil derivatives. The Polycin GR series polyols are all-natural, renewable resource products made by Vertellus using only castor oil as a raw material. It is claimed that the mechanical properties obtained from this series of products have never before been achieved in ricinoleic acid glyceride polyurethane products. Curing these polyols with MDI yields polyurethane elastomers with a wide range of hardness. The low-viscosity Polycin D, M, and T products, as well as the castor oil-based polyols in the Caspol series, are light yellow liquids and are recommended as reactive diluents and modifying polyols for 100% solids and low-VOC polyurethane and melamine cross-linked coatings. Applications include: formulating 100% solids high-performance polyurethane coatings, low-VOC UV-resistant two-component industrial maintenance coatings and thermosetting OEM coatings; used as a performance modifier for flexibility, moisture resistance, and chemical resistance in coatings, adhesives, sealants, and elastomeric materials; low-VOC forced-drying topcoats and primers for plastics and metals; and reducing viscosity and solvent use in coatings and adhesives.

Lupranol Balance 50 from Elastogran (a subsidiary of BASF) is a natural oil-based polyol product based on castor oil, containing 31% castor oil. It is obtained by ring-opening polymerization of propylene oxide/ethylene oxide on the hydroxyl groups of castor oil using a double metal cyanide (DMC) catalyst to produce a castor oil polyether polyol. Lupranol Balance 50 has a typical hydroxyl value of 50 mg KOH/g, a functionality of approximately 2.7, a typical viscosity of 725 mPa·s, and low odor. It is mainly used as a soft foam polyether polyol.

The Uric H series of castor oil-based polyols from Itoh Oil Chemicals Co., Ltd. includes Uric H30 (refined castor oil), Uric H52, H56, and H57 (polyether-modified castor oil), and other high-performance oligomeric polyols based on castor oil. Uric H series castor oil-based polyols are used in CASE polyurethane materials, exhibiting better thermal stability, hydrolysis resistance, acid resistance, and chemical resistance than general polyether and polyester polyurethanes, and possessing excellent flexibility, electrical insulation, wear resistance, and impact resistance. Uric Y polyols have low viscosity and are suitable as reactive diluents for two-component polyurethanes. They have good compatibility with polyolefin polyols and improve mechanical properties such as tensile strength and elongation. Uric Y331 and Y332 do not contain double bonds, exhibiting excellent weather resistance and yellowing resistance, and can also be used as reactive diluents for polyisoprene polyols. Uric AC is a castor oil-based polyol containing an aromatic backbone, used in solvent-free polyurethane systems. The Uric PH series are special castor oil-based polyols that, when combined with different polyisocyanate curing agents, yield soft, high-elongation polyurethane elastomers with better thermal stability and hydrolysis resistance than typical polyether and polyester polyurethanes.