PROCESS FOR THE PREPARATION OF POLYALPHAOLEFINE FIBRIDS OBTAINED THEREBY

摘要

: The invention relates to a process for the production of polymeric products in the from of fibrids, comprising polymerizing at least one compound containing at least one olefinic unsaturation in the presence of a catalytic system comprising a reducing aluminium compound and a compound of a transition metal selected from the groups IV and VIII of the Periodic System, the aluminium compound being selected either among organometallic compounds having the general formula Al RxX3-x wherein R is an aryl, alkyl or cycloalkyl radical, X is a hydrocarbon radical or hydrogen, x is a whole or fractional number between 0 and 3 or among polymeric compounds of polyiminic nature containing repeating units of the type (AlH-NR) where is R has the aforesaid meaning, the catalytic system having a Al Me ratio, wherein Me represents the transition metal, ranging from 1 to 200 and a total concentration of the transition metal, ranging from 1 to 200 and a total concentration of the transition metal compound ranging from 0.001 to 5 mmoles/1, in a solvent selected among those having good solvent power for the monomer and low solvent power for the polymer which forms, at a temperature comprised between 0.degree.C and -20.degree.C, when the catalytic system comprises aluminium compounds AlRxX3-x and vanadium compounds, between 50.degree.C and 90.degree.C, when the catalytic system comprises a polyiminoalane and a titanium compound, and between -15.degree.C and +90.degree.C, when the catalytic system comprises a polyiminoalane and a vanadium compound. It is therefore possible to obtain fibrids directly during polymerisation without application of shear stress. The fibrids of the present invention can be used as synthetic pulp for the production of papers.