Butanediol 1,4 (BDO) is made for both the hard and soft segments of polyurethanes. It can serve as a chain extender, or as polyesterdioles such as polybutylene adipate glycol. BDO makes a variety of esters, including monomeric plasticizers, the engineering plastic polybutylene terephthalate (PBT) and low molecular weight polyester glycols.
The reaction between BDO and various dibasic acids (e.g., adipic and sebacic) produces polyester glycols for soft segments in polyurethanes. In the hard segments, particularly those made with MDI, the use of BDO provides balance between hardness and low temperature flexibility.
BDO in Polyesters
Products such as poly (butylene adipate) glycol yield urethanes with excellent resistance to oils, solvents and ultraviolet light. These urethanes exhibit good mechanical properties at room and elevated temperatures, as well as high resistance to flexing and abrasion. Urethanes made from polyester glycols generally show better metal adhesion than those derived from polyethers.