Formulators of coatings, adhesives, sealants, and elastomers (CASE), as well as makers of foams and elastic fiber applications, utilize a diverse family of polyols to meet specifications for product performance. These polyols include polytetramethylene ether glycols (PTMEG), polypropylene glycols (PPG), adipate- and phthalate-based polyesters, polycaprolactone polyols, and polycarbonate polyols.
Selecting the best polyol for a specific formula can be the difference between making a high-quality product or a low-performance offering. The key for proper material selection is a good understanding of the inherent characteristics of each polyol chemistry, a level of business intelligence that's a hallmark of the Ganrade team. PTMEG is the premier polyol used in high-performance polyurethane elastomers. PTMEG-based polyurethanes are known for superior resistance to hydrolytic cleavage, good mechanical properties retention at low temperature, high resiliency, good processing characteristics and excellent mechanical and dynamic properties.
Strain-induced crystallization of the PTMEG soft segments, exact difunctionality and low acid values are all contributing factors to the superior mechanical properties of the associated polyurethane elastomers. These factors make PTMEG the material of choice for processors specializing in wheels, belts, tires, tubing, abrasion-resistant surfaces, and many other products.
Compared with polyester-type polyurethanes, the PPG-polyether polyols also exhibit excellent hydrolysis resistance and low temperature properties. However, when compared with the PTMEG and polyester polyols, the PPG polyols have inferior mechanical properties and are more prone to thermo-oxidative degradation.
In contrast to PPG polyols, polyester polyols possess better mechanical properties, such as tensile and tear strength and flex fatigue resistance. Polyester polyols are reaction products of dicarboxylic acids and diols, and polyester segments can be crystalline or amorphous. These polyesters are more resistant to oil, grease, solvents, and oxidation.
The polycaprolactone polyols exhibit lower melt viscosities, a narrower molecular weight distribution, and low acid values which improve their hydrolytic stability. The polycarbonate polyols are characterized by superior heat and moisture resistance vs. polyester polyols.