ABSTRACT
Until recently, the greatest use of the HER™ chain extender family, in particular HER-HP, had been noted in MDI applications where higher hardness, tougher tear, higher tensiles and resistance to fatigue were necessary properties. The most recent evaluation of HER™ products in the chain extension of TDI prepolymers (low free isocyanate and conventional systems) suggests there are new opportunities for longer chain HER™ in the production of “lower durometer” TDI elastomers without the use (or with reduced use) of plasticizers; depending upon the target hardness.
The HER™ product line is comprised of various grades that include a powder at room temperature, waxy solids, and liquid at room temperature consistencies. The information within presents the physical properties and resistance to solvents that can be attained with HER™ extension of TDI prepolymers. Much of the data readily pertains to roll cover applications (e.g. inks & coatings) but other uses where durable low durometer “plasticizer free" properties are needed will also find this data to be of value. The results of this study provide TDI’s an opening to commercial applications requiring physical performance at low hardness with resistance to solvent attack.
