Polyols are used in the manufacture of Polyurethane Foams (PU), which find extensive use in the automotive, construction, refrigeration and other industrial sectors. Polyurethane Foams can be broadly classified as flexible, semi rigid, molded and rigid foams. Other important applications are in the manufacture of thermoplastic elastomers, coatings, adhesives, artificial leather and medical devices.

Commercially, Polyether Polyol is manufactured by ethoxylation/ propoxylation of a polyhydric alcohol in the presence of a catalyst. The polyhydric alcohols used are ethylene glycol, di-propylene glycol, di-ethyelene glycol, and glycerol. Carbohydrates such as Sorbitol, Mannitol, triethanolamine. Sucrose is also used as polyhydric alcohol in the preparation of Polyether Polyols for making Polyurethane Foam.

The polyester polyols used in the manufacture of polyurethane are required to be hydroxyl terminated. Polyester polyol is prepared by reacting an excess of the stoichiometric amount of difunctional glycol with dibasic acid. The manufacture is usually carried out through a batch process. The most widely used Polyester Polyol is polyethylene adipate.

Polyols used in manufacture of polyurethane have very low toxicity. High molecular weight Polyether Polyols derived from Propylene Oxide and copolymers of propylene oxide and ethylene oxide have a low oral toxicity. Polyols are not irritating to the eyes & skin. Similarly, Polyester Polyols also have low toxicity.

Although Polyols have low toxicity, the raw material from which they are manufactured e.g. ethylene oxide, propylene oxide are highly toxic. Ethylene oxide is toxic both in gaseous and liquid form. The current TWA is 1 ppm. Like EO, Propylene oxide is also a toxic material. The AGGIH recommends an 8h-TWA limit of 20 ppm.