AU/EU Rubber

Millable Polyurethane Rubber can be processed with typical rubber processing equipment although it exhibits the properties of polyurethane (TPU and cast). Tipically, curing can be performedwith sulfur or peroxide; some special grades exploit isocyanate-based curatives. Polyurethane Rubber is produced with a stoichiometric deficiency of di-isocyanate compared to TPU where the di-isocynate is slightly in excess. This specific feature enables to benefit from the advantages of polyurethane elastomers with conventional equipment. In addition, extra properties can be achieved by adding fillers, additives and blending with other polymers. Polyurethane consists of a polyol (e.g.: polytetramethylene ether glycol [EU] or polyesteradpates [AU], a diisocyanate (normally MDI or TDI) and a chain extender (e.g.: ethylene glycol, 1,4-butandiol). The chemical composition of polyurethanes largely determines its range of properties and is thus of vital significance. The poylurethanes based on polytetrametylene glycol provides excellent hydrolysis resistance; ethylene glycol adipate provides excellent oil&fuel resistance, but poor hydrolysis resistance; butandiol gives excellent low temperature properties; Hexanediol adipates imparts hydrolysis resistance and heat resistance.  Cyclohexanedimethanol affords very low gas permeation.