Several new low-volatile pure monomer resins with varying softening points have been developed in response to general demand for low-VOC raw materials.
Pure monomer resins (PMRs) are produced from pure aromatic monomer streams, especially styrene and alkyl styrene derivatives. Major advantages of PMRs, compared to other aromatic crude C-9 resins, include light color (water white), excellent thermal stability, temperature resistance (similar to hydrogenated hydrocarbon resins) and controlled molecular weight.1-3
PMRs are typically manufactured using Lewis acids/Friedel-Crafts catalysis of styrenic/alkyl styrenic monomer. Pennsylvania Industrial Chemical Corp./Hercules pioneered the process in early 1960s.4-7 Since then, several PMRs have been commercialized with varying vinyl aromatic chemistries and properties (softening points, molecular weight, etc.).