Linear low density polyethylene for film applications

A process for producing a polyethylene composition, comprising:

• introducing, under first polymerization conditions, ethylene and a C3-C40 alpha-olefin to a catalyst system in a reactor, the catalyst system comprising a first catalyst compound, a second catalyst compound, and an activator;
• and
• forming a polyethylene composition, the first catalyst compound being represented by Formula (I)
• wherein:
• M is Ti, Hf, or Zr;
• each of X1 and X2 is independently C1 to C20 hydrocarbyl radical, a functional group comprising elements from Groups 13 to 17 of the periodic table of the elements, or X1 and X2 join together to form a C4 to C62 cyclic or polycyclic ring structure;
• each of R1, R2, R3, R4, R5, R6, R14, R15, and R16 is independently selected from hydrogen, halogen, C1-C40 hydrocarbyl, substituted C1-C40 hydrocarbyl, —NR′2, —SR′, —OR′, —OSiR′3, or —PR′2, wherein each R′ is independently hydrogen, halogen, C1-C10 alkyl, or C6-C10 aryl, or one or more of R1 and R2, R2 and R3, R3 and R4, R4 and R5, R1 and R5, R14 and R15, and R15 and R16 join together to form a C4 to C62 cyclic or polycyclic ring structure;
• each of R7, R8, R9, R10, R11, R12, R13 is independently selected from hydrogen, halogen, C1-C40 hydrocarbyl, substituted C1-C40 hydrocarbyl, aryl, substituted aryl, —NR′2, —SR′, —OR′, —OSiR′3, or —PR′2, wherein each R′ is independently hydrogen, halogen, C1-C10 alkyl, or C6-C10 aryl, or one or more of R7 and R8, R8 and R10, and R10 and R12 are joined to form a saturated ring, unsaturated ring, substituted saturated ring, or substituted unsaturated ring;
• and the second catalyst compound being represented by Formula (IIa) or Formula (IIb):
• wherein:
• each of R6a, R10a, R11a, and R15a are independently halogen, —CF3, or C1-C22-alkyl, C2-C22-alkenyl, C6-C22-aryl, arylalkyl (wherein alkyl has from 1 to 10 carbon atoms and aryl has from 6 to 20 carbon atoms), NR′2, —OR′, —SiR″3 or five-, six- or seven-membered heterocyclyl comprising at least one atom selected from N, P, O and S;
• each of R1a and R2a is independently hydrogen, C1-C22-alkyl, C2-C22-alkenyl, C6-C22-aryl, arylalkyl wherein alkyl has from 1 to 10 carbon atoms and aryl has from 6 to 20 carbon atoms, or five-, six- or seven-membered heterocycle comprising at least one atom selected from N, P, O and S, wherein each of R1a and R2a is optionally substituted by halogen, —NR′2, —OR′ or —SiR″3, wherein R1a optionally bonds with R3a, and R2a optionally bonds with R5a in each case to independently form a five-, six- or seven-membered ring;
• each of R3a, R4a, R5a, R7a, R8a, R9a, R12a, R13a, and R14a is independently hydrogen, C1-C22-alkyl, C2-C22-alkenyl, C6-C22-aryl, arylalkyl wherein alkyl has from 1 to 10 carbon atoms and aryl has from 6 to 20 carbon atoms, halogen, —NR′2, —OR′, —SiR″3 or five-, six- or seven-membered heterocyclyl comprising at least one atom selected from N, P, O and S;
• and
• each of X1a and X2a is independently hydrogen, halogen, C1-C20-alkyl, C2-C10-alkenyl, C6-C20-aryl, arylalkyl wherein alkyl has from 1 to 10 carbon atoms and aryl has from 6 to 20 carbon atoms, —NR′2, —OR′, —SR′, —SO3R′, —OC(O)R′, —CN, —SCN, β-diketonate, —CO, —BF4−, —PF6− or bulky non-coordinating anion, or X1a and X2a optionally bond to form a five- or six-membered ring;
• wherein the catalyst system is formed by steps including first adding the catalyst compound represented by Formula (IIa) or Formula (IIb) to a silica support with a first solvent to form a pre-treated iron silica support, then contacting the pre-treated iron silica support with the activator, and then contacting the pre-treated iron silica support with the catalyst compound represented by Formula (I) with a second solvent, wherein the first solvent and the second solvent are optionally different or same.