Alpha-olefins such as 1-decene are copolymerized with vinylaromatic monomers, especially styrene or the alkylstyrenes, to produce liquid lubricant oligomers having a broad range of viscosities, high viscosity index(VI), improved thermal stability and additive solubility characteristics. The lubricant oligomers are random copolymers containing recurring units of 1-alkene and vinyl aromatic monomer in mole ratios between 2:1 and 500:1, but preferably between 5:1 and 100:1 and more preferably from about 10:1 to 50:1. The recurring 1-alkene units of the copolymer have a branch ratio of less than 0.19, indicative of a poly 1-alkene segment of the copolymer chain or backbone that is essentially linear. The copolymerization catalyst is a reduced Group VIB metal catalyst on porous support, preferably reduced chromium oxide on a silica support.
Please note there is up to 60 days of latency in this Status indicator for certain status conditions. You can obtain up-to-date Status indicator readings by ordering PAIR for the file.
An application with the status "Published" (which means it is pending) may be recently abandoned, but not yet updated to reflect its abandoned status. However, an application filed less than one year ago is unlikely to be abandoned.
A patent with the status "Granted" may be recently expired, but not yet updated to reflect its expired status. However, it is highly unlikely a patent less than 3.5 years old would be expired.
An application with the status "Abandoned" is almost always current, but there is a small chance it was recently revived and the status not yet updated.
This priority date is an estimated earliest
priority date and is purely an estimation. This date should not be
taken as legal conclusion. No representations are made as to the
accuracy of the date listed. Please consult a legal professional
before relying on this date.