Polycaprolactone polyols are considered a special class of aliphatic polyester polyols, used as the soft block segment of high-performance polyurethane elastomers. The polycaprolactone polyols can be produced with very low acid values; perfect end-termination functionality; and narrow molecular weight distributions (MWD). These features manifest themselves in polyurethanes characterized by the following property profile, many of which are best-in-class performance attributes.
1,4-butanediol (BDO/1,4-BD) is a versatile liquid diol intermediate with reactive primary hydroxyl functionality and a linear structure that lends itself to formulating polyurethanes with a good balance of hardness and low temperature flexibility; high strength and durability; and thermal stability.
Polyurea is formed by reaction of diisocyanates and diamines, and it is one of the toughest synthetic polymer materials. These are some of its attributes:
When using cast polyurethane systems, the polyurethane casting process requires the right temperature for polyurethane components that are used in the process. Cast polyurethanes are processed in a liquid state. That is to say that the individual components of the system are liquified prior to mixing and then the mixed compound is cast into a mold or poured onto a surface to allow the cure to advance to a solid state.
When it comes to MDI systems, the chain extender of choice for most processors is 1,4-Butanediol (BDO). Even though BDO possesses good physical properties and an easy liquid form, its higher freezing point, hygroscopic character, and regulative control may leave processors wondering if there are other chain extender alternatives.
What many manufacturers may not realize is that 2-Methyl-1,3-propanediol (MPO) is a viable substitute for BDO.
The most commonly used chain extenders with 4,4’-diphenylmethyl diisocyanate (MDI) terminated prepolymers are 1,4-butanediol (BDO) and hydroquinone bis (2-hydroxyethyl) ether (HQEE).
