| abstract |
A process is disclosed for the preparation of chlorinated poly(vinyl chloride), (hereinafter "CPVC" for brevity), in the form of free-flowing macrogranules which are derived from solid free-flowing macrogranules of poly(vinyl chloride), (hereinafter "PVC" for brevity), by causing from about 0.6 to about 3.0 parts by weight (wt) of liquid chlorine which are absorbed perunit wt of solid PVC macrogranules to react with the PVC, without shedding reacted material from the macrogranules. The macrogranules of PVC containing absorbed liquid chlorine held therewithin, are maintained in a wetted but free-flowing, apparently dry reaction mass (due to which the process is referred to as "the relatively dry chlorination" or "the low liquid chlorine" process), in a reaction zone maintained at a temperature in the range from about -50 DEG C. to about 50 DEG C., and a pressure sufficient to maintain the chlorine in its liquid state. The reaction is carried out in the presence of actinic radiation, but without swelling agents and the like. The process may be operated as a batch process, or a continuous process. The CPVC formed by the process of this invention has improved processing and working characteristics. This CPVC is distinguishable from prior art CPVC compositions by its spectral fingerprint, and by the presence of 5-15 percent by weight (% by wt) of the CPVC as glassy macrogranules. In another embodiment of the invention, a process is disclosed for simultaneously chlorinating (hence "co-chlorinating") a free-flowing mixture of solid PVC macrogranules and solid polyethylene ("PE") particles, without shedding reacted material from the macrogranules, to yield a mixed reaction product of separate macrogranules of CPVC and particles of chlorinated polyolefin, which mixture, in a preselected ratio of its components, may be directly used in an injection molding machine. The reaction product formed by the co-chlorination process is visually distinguishable by the characteristic coating of individual CPVC macrogranules with particles of chlorinated polyethylene ("CPE" for brevity). |