Plasticizers for Polyurethane Elastomers

Only specific classes are compatible with particular polyurethane elastomer types. Polyether-based urethanes are compatible with such esters as dioctylphthalate (DOP) and its many analogues. Polyester-based urethanes are not compatible with these phthalate-based esters. Instead, polyester-based urethanes are only compatible with benzoate-based esters. A typical example is dipropylene glycol dibenzoate.t 

Many aspects of manufacturing have been covered in Chapter 6 on RIM. However, there are some additional factors which apply to the fully solid polyurethane elastomers (the RIM materials are microcellular). 

Moulds are made from steel, aluminium and sometimes from solid polyurethane or silicone rubber or occasionally glass-reinforced plastic (polyester or epoxy resins). For long life, case-hardened steel is very satisfactory. Air vents are recommended as OT mm (0 004 in) between horizontal mould plates. 

For injection-moulded TPU the injection gate must be significantly larger than for other thermoplastic materials. 

---