摘要：

OF THE DESCROSURE Processes for polymerizing alpha olefinic hydrocarbons comprising polymerizing an alpha olefin with a solid Stereospecific catalyst in the presence of a diluent which is a solvent for the poly-alpha-olefin at the reaction tem perature to produce a polymer solution containing cata lyst residues. The polymer solution is filtered to remove catalyst residues. The filtered solution is contacted with alumina and concentrated to form a solid polymer con centrate containing residual solvent. Pellets are formed of the polymer concentrate and the pellets extracted with a solvent for amorphous low molecular weight polymer to produce a highly crystalline polymer substantially free of impurities. This application is a continuation-in-part application of Ser. No. 636,118, filed May 4, 1967 and now aban doned. This invention relates to a process for the preparation of Solid olefinic hydrocarbon polymers. More particularly, this invention relates to a process for the preparation of Substantially ash free, non-corrosive solid polymers pre pared by Solution polymerization of olefins employing high temperature stereoSpecific lithium containing cata lysts, which polymers have excellent color. In recent years Solid, high molecular weight polymers which are partially or substantially crystalline have been prepared from olefinic hydrocarbons such as ethylene and propylene by low pressure polymerization of the monomer in the presence of solid stereospecific polym erization catalysts. Such polymers have been used exten sively in a number of different applications including, for example, fibers, molding and coating applications. These polymers are, however, deficient for many uses because they contain metal contaminants (ash) caused primarily by the catalyst Systems used in their prepara tion. It is particularly difficult to obtain polymers free of catalyst residues because they are present in the polym erization partly in dissolved form, partly as solid particles and partly in a form completely enclosed by the polymer. The quantities of ash present in the aforementioned poly mers vary from about 0.3 to about 0.5 weight percent and cause the polymer to discolor badly during process ing. Such ash may also unfavorably affect the electrical properties of the polymer. In addition, these relatively high ash contents cause the polymer to exhibit some de gree of instability and may corrode materials commonly used in processing apparatus. Polymers having ash con tents as high as .05 weight percent have been found to be satisfactory for some commercial applications, but for many other applications these polymers should be sub stantially free of ash, i.e., exhibit ash contents of .01 weight percent or less. Thus, the tendency of polymers to darken or degrade upon being shaped, molded or otherwise formed into fibers, film or other structures, par ticularly when exposed to heat or upon exposure to light, is, for all practical purposes, eliminated when the ash content of the polymer is .01 weight percent or less. It is obvious, therefore, that a simple, direct and commer O

展开