Syndiotactic propylene polymers and lubricating oils comprising the same

A lubricating oil composition comprising:

• (i) at least 50 wt % of a base oil based on the weight of the lubricating oil;
• and
• (ii) a syndiotactic polymer containing units derived from at least one α-olefin having 4 to 10 carbon atoms and ≥50 mol % of units derived from propylene, wherein the polymer has a melt flow rate, as determined by ASTM D-1238 (2.16 kg, 230° C.), of about 1 g/10 m to about 10 g/10 min, and wherein the lubricating oil composition comprises about 0.1 wt % to about 10 wt % of the polymer based on the weight of the lubricating oil composition;
• wherein the polymer is produced by a polymerization process comprising contacting propylene and at least one α-olefin having 4 to 10 carbon atoms with a catalyst system comprising a precatalyst compound and an activator in a reactor;
• wherein the precatalyst compound is selected from those having the structure of formula (1), (2), (3), or (4);
• wherein structure (1) has a Cs or pseudo-Cs symmetry and the following formula (1):
• wherein
• M is a zirconium;
• L1 is a unsubstituted fluorenyl, unsubstituted heterocyclopentapentalenyl, unsubstituted heterofluorenyl, substituted fluorenyl, substituted heterocyclopentapentalenyl, or substituted heterofluorenyl ligand with one or more symmetric or pseudo symmetric substituents, each substituent group being, independently, a radical group which is a hydrocarbyl, substituted hydrocarbyl, halocarbyl, substituted halocarbyl, silylcarbyl or germylcarbyl, and optionally two or more adjacent substituents may join to form a substituted or unsubstituted, saturated, partially unsaturated or aromatic, cyclic or polycyclic substituent;
• L2 is a cyclopentadienyl ring or a substituted cyclopentadienyl ring with one or more symmetric or pseudo symmetric substituents in the 2 and 5 positions of the ring, each substituent group being, independently, a radical group which is a hydrocarbyl, substituted hydrocarbyl, halocarbyl, substituted halocarbyl, silylcarbyl or germylcarbyl;
• G is a bridging group;
• and
• X are, independently, halogen, alkoxide, aryloxide, amide, phosphide, hydride radicals, hydrocarbyl radicals, substituted hydrocarbyl radicals, halocarbyl radicals, substituted halocarbyl radicals, silylcarbyl radicals, substituted silylcarbyl radicals, germylcarbyl radicals, or substituted germylcarbyl radicals;
• or both X are joined and bound to the metal atom to form a metallacycle ring containing from 3 to 20 carbon atoms;
• or both together can be an olefin, diolefin or aryne ligand;
• or both X can also be joined to form a anionic chelating ligand;
• wherein structure (2) has Cs or pseudo-Cs symmetry and the following formula (2):
• wherein:
• M, L1, G, and X are the same as in structure (1);
• J is a heteroatom from group 15;
• R′ is a radical group which is a hydrocarbyl, substituted hydrocarbyl, halocarbyl, or substituted halocarbyl;
• and
• L′ is a neutral Lewis base and w represents the number of L′ bonded to M where w is 0, 1, or 2, and optionally any L′ and any X may be bonded to one another;
• wherein structure (3) has Cs or pseudo-Cs symmetry and the following formula (3):
• wherein:
• M and X are the same as in structure (1);
• L3 is a cyclopentadienyl ring optionally substituted in the 4 position of the ring, the substituent group being chosen from a radical group which is a hydrocarbyl, substituted hydrocarbyl, halocarbyl, substituted halocarbyl, silylcarbyl or germylcarbyl;
• L4 is a substituted cyclopentadienyl ring with symmetric or pseudo symmetric substituents in the 3 and 5 positions of the ring, each substituent group being, independently, a radical group which is a hydrocarbyl, substituted hydrocarbyl, halocarbyl, substituted halocarbyl, silylcarbyl or germylcarbyl;
• and
• G′ and G″ are bridging groups;
• and
• wherein structure (4) has C2 symmetry and the following formula (4):
• wherein:
• X is the same as in structure (1);
• M is titanium;
• O is oxygen;
• N is nitrogen;
• R1 is a radical group which is a hydrocarbyl, substituted hydrocarbyl, halocarbyl, substituted halocarbyl, silylcarbyl or germylcarbyl;
• R2 is a radical group which is a hydrocarbyl, substituted hydrocarbyl, halocarbyl, substituted halocarbyl, silylcarbyl or germylcarbyl;
• and
• RL3, R4 and R5 are independently hydrogen or a radical group which is a hydrocarbyl, substituted hydrocarbyl, halocarbyl, substituted halocarbyl, silylcarbyl or germylcarbyl.