C5 aliphatic petroleum resin and C9 aromatic petroleum resins can be modified by mixing the two feed streams together at a carefully chosen ratio to produce hybrid polymers. This ratio determines the aliphatic/aromatic balance of the resin, which is an essential determinant of the resin’s compatibility. The MMAP and DACP cloud points are the method used to characterize C5/C9 resins. As the cloud points decrease, the compatibility with polar and aromatic polymers increases.
This variation in aliphatic and aromatic composition accounts for solubility differences that enable these products to be useful in natural rubber, styrene butadiene rubber (SBR), nitrile-butadiene rubber (NBR), block copolymers, and ethylene vinyl acetate (EVA) for hot melt systems. The solubility and stability of C5/C9 hydrocarbon resins makes them especially useful in producing hot melt adhesives for nonwoven product construction based on styrene-butadiene-styrene (SBS) block copolymers. These resins develop superior tack in SBS systems as well as reducing the melt viscosity. Straight C5 aliphatic resins or C9 aromatic petroleum resins cannot perform both of these functions simultaneously. Mixed aliphatic/aromatic resins are manufactured with varying proportions of the previously described C5 and C9 feedstocks to produce resins with a range of softening points and molecular weights.
Table 1: Property Ranges of C5/C9 Aliphatic/Aromatic Copolymerized Petroleum Resins

Properties	Range
Ring and ball softening point, °C	90–105
Gardner color (50% in toluene)	5–12
Glass transition temperature, °C	7–50
MMAP cloud point, °C	65–90
DACP cloud point, °C	8–65

C5/C9 aliphatic/aromatic copolymerized petroleum resins produced by LESCO CHEMICAL LIMITED are:
LESTAC-CC Series Cold Polymerization C5/C9 Copolymerized Petroleum Resin
LESTAC-TC Series Thermal Polymerization C5/C9 Copolymerized Petroleum Resin