High temperature bulk polymerization of branched crystalline polypropylene

A process of preparing a polymer composition that comprises branched crystalline polypropylene, said process comprising:

• combining a metallocene catalyst compound with propylene monomers in a polymerization medium having less than 30 volume percent diluent;
• conducting polymerization of the propylene monomers in the polymerization medium at a reaction temperature of over 70° C. to form branched crystalline polypropylene;
• and
• recovering branched crystalline polypropylene that has from 0.0 wt % to 2.0 wt % ethylene and a heat of fusion of 70 J/g or more.

A process of preparing a branched crystalline polypropylene composition, comprising:

• combining a catalyst system that comprises a metallocene compound with a polymerization mixture that comprises propylene monomers in a reactor system, and carrying out polymerization of the propylene monomers in the reactor system for a time sufficient to form branched crystalline polypropylene, in which:
• the metallocene compound is represented by the formula:
• 13
• wherein:
• M1 is selected from the group consisting of titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum and tungsten;
• R1 and R2 are identical or different, and are one of a hydrogen atom, a C1-C10 alkyl group, a C1-C10 alkoxy group, a C6-C10 aryl group, a C6-C10 aryloxy group, a C2-C10 alkenyl group, a C2-C40 alkenyl group, a C7-C40 arylalkyl group, a C7-C40 alkylaryl group, a C8-C40 arylalkenyl group, an OH group or a halogen atom;
• R1 and R2 may also be joined together to form an alkanediyl group or a conjugated C4-40 diene ligand which is coordinated to M1 in a metallocyclopentene fashion;
• R1 and R2 may also be identical or different conjugated dienes, optionally substituted with one or more hydrocarbyl, tri(hydrocarbyl)silyl groups or hydrocarbyl, tri(hydrocarbyl)silylhydrocarbyl groups, said dienes having up to 30 atoms not counting hydrogen and forming a π complex with M, examples include 1,4-diphenyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, 2,4-hexadiene, 1-phenyl-1,3-pentadiene, 1,4-dibenzyl-1,3-butadiene, 1,4-ditolyl-1,3-butadiene, 1,4-bis(trimethylsilyl)-1,3-butadiene, and 1,4-dinaphthyl-1,3-butadiene;
• Each R3 is identical or different from the other R3 and is each a hydrogen atom, a halogen atom, a C1-C10 alkyl group which may be halogenated, a C6-C10 aryl group which may be halogenated, a C2-C10 alkenyl group, a C7-C40-arylalkyl group, a C7-C40 alkylaryl group, a C8-C40 arylalkenyl group, a —NR′2, —SR′, —OR′, —OSiR′3 or —PR′2 radical, wherein R′ is one of a halogen atom, a C1-C10 alkyl group, or a C6-C 10 aryl group;
• R4 to R7 are identical or different and are hydrogen, or are as defined for R3 or two or more adjacent radicals R5 to R7 together with the atoms connecting them form one or more rings;
• 14 —B(R14)—, −Al(R14)—, —Ge—, —Sn—, —O—, —S—, —SO—, —SO2—, —N(R14)—, —CO—, —P(R14)—, or —P(O)(R14)—;
• wherein:
• R14, R15and R16 are identical or different and are a hydrogen atom, a halogen atom, a C1-C20 branched or linear alkyl group, a C1-C20 fluoroalkyl or silaalkyl group, a C6-C30 aryl group, a C6-C30 fluoroaryl group, a C1-C20 alkoxy group, a C2-C20 alkenyl group, a C7-C40 arylalkyl group, a C8-C40 arylalkenyl group, a C7-C40 alkylaryl group, or R14 and R15, together with the atoms binding them, form a cyclic ring;
• or, R13 is represented by the formula:
• 15
• wherein:
• R17 to R24 are as defined for R1 and R2, or two or more adjacent radicals R17 to R24, including R20 and R21, together with the atoms connecting them form one or more rings;
• M2 is one or more carbons, silicon, germanium or tin;
• and
• R8, R9, R10, R11 and R12 are identical or different and have the meanings stated for R4 to R7.