Abstract: Recently, as a process for manufacturing cyclopentadiene resin-shaped articles, an attention has been given to reaction injection molding (RIM). To conduct RIM, it is necessary to use high purity dicyclopentadiene (DCPD) as the raw material. Vapor-phase thermal cracking of DCPD is usually used as a step of process for manufacturing high purity DCPD. Hithertofore, when conducting thermal cracking of DCPD, coke formation within cracking tubes is the most serious and troublesome problem. A vapor-phase thermal cracking process for resolving the problem by a very simple procedure is described herein. Further, a process for manufacturing high purity DCPD suitable as a raw material for use in RIM utilizing the vapor-phase thermal cracking process just mentioned above is also described.

Abstract: A process for manufacturing a petroleum resin is disclosed. The process comprises, polymerizing a petroleum fraction containing unsaturated hydrocarbons in the presence of Friedel-Crafts catalyst, and washing the polymerized product with water or an alkaline solution in the presence of 1-200 ppm of a polymer having a hydroxyl value of 40-120 mg KOH/g and represented by formula (I): ##STR1## wherein R.sub.1 represents a C.sub.4-16 alkyl group, each R.sub.2 individually represents H or a methyl group, each X individually represents H, an alkyl or an aminomethyl group, n is an integer of 0-8, and m is an integer of 8-20. The process can remarkably shorten the time required for the separation of oil from water after the polymerization, producing transparent, light-colored, petroleum resins with a low ash content.

Abstract: A hydrogenated petroleum resin is provided, which features excellent heat stability and good compatibility with polar polymers. The resin provides an adhesive compound in combination with such a polar polymer, exhibiting an outstanding adhesion capability. The resin is prepared by copolymerization of a C.sub.5 fraction, containing diolefins and monoolefins in a specific proportion, and an aromatic monoolefin, followed by a proper degree of hydrogenation of the copolymer.