MPDiol Glycol is used in the production of unsaturated polyester resins (UPRs). UPRs are the most commonly used thermoset resins in the world.
There are approximately 2.2 billion kilograms/year of UPR used around the globe in the manufacturing of a wide assortment of products, including sinks, shower stalls, pipes, tanks, gratings and high performance components for boats, buses, trucks, trailers and automobiles.
These versatile resins are made from aromatic acids (isophthalic, terephthalic, and phthalic anhydride), reacted with a glycol (typically propylene glycol(PG)) or mixture of glycols, and maleic anhydride. The polymer thus generated is diluted with styrene monomer to adjust the viscosity and form the final resin composition.
Ortho resins (made from phthalic anhydride) are the least expensive class of resin and are used when the structural and corrosion requirements of the part are low. Iso(phthalate) resins have very good structural and corrosion properties, but with their relatively high cost are used only in demanding applications. Tere(phthalate) resins are currently made in small volumes and are considered a specialty resin. A major reason for the limited availability of terephthalate resins is the difficulty in making these resins from terephthalic acid (TPA) and PG.
Even though PG is the predominant glycol used in producing all types of UPRs, other glycols are used including neopentyl glycol (NPG), diethylene glycol (DEG) and ethylene glycol (EG). Each of these glycols, when used in production of a polyester resin, makes a contribution to the final set of polymer characteristics, including heat distortion temperature (HDT), water uptake, strength, weatherability, etc.
Benefits and Applications
The unique structure of MPDiol glycol provides a variety of advantages including both improvements in processing and in final polymeric properties. It is a low viscosity, clear liquid, with very little odor, that is easy to handle in a manufacturing environment. MPDiol glycol contains two very reactive primary hydroxyls. It is therefore inherently more reactive than the industry standard glycol, PG.
It also has a boiling point that is 30 degrees C higher that PG, making it possible to run reactions at a higher temperature (faster). MPDiol glycol can be used to make UPRs in one stage or two stage reactions similar to the way other glycols are used. The use of MPDiol glycol when reacted into an unsaturated polyester (ortho, iso, tere) routinely forms polymers with improved strength and ductility, and also produces UPRs with excellent corrosion resistance.
MPDiol is a trademark owned or used by LyondellBasell group companies. Trademark MPDiol is registered in the U.S. Patent and Trademark Office.