Process to produce thermoplastic elastomers

• US 5,516,848 A
• Filed: 01/31/1995
• Issued: 05/14/1996
• Est. Priority Date: 01/31/1995
• Status: Expired due to Fees

• Current Assignee: Exxon Chemical Patents Inc. (Exxon Mobil Corporation)
• Original Assignee: Exxon Chemical Patents Inc. (Exxon Mobil Corporation)
• Inventors: Licciardi, Gary F., Canich, Jo Ann M., Yang, Henry W.
• Primary Examiner(s): Seccuro, Jr., Carman J.
• Application Number:
  US08/381,171
• Time in Patent Office: 469 Days
• Field of Search: 525/240
• US Class Current: 525/240
• CPC Class Codes: C08L 2205/02 containing two or more polymers of the same C08L -group
• CPC Class Codes: C08L 2205/025 containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure
• CPC Class Codes: C08L 2207/14 Amorphous or atactic polypropylene
• CPC Class Codes: C08L 23/10 Homopolymers or copolymers of propene
• CPC Class Codes: C08L 2666/06 Homopolymers or copolymers of unsaturated hydrocarbons; Derivatives thereof

Abstract

This invention relates to polypropylene blends, particularly blends of high molecular weight amorphous polypropylene with lower molecular weight isotactic polypropylene. These blends exhibit unusual elastomeric properties.

Claims

1. A process for producing a polypropylene composition comprising:

selecting a first catalyst system comprising an activator and a monocyclopentadienyl transition metal compound capable of producing an amorphous polypropylene having a Mw of at least 150,000 and a Mw/Mn of less than 3;

selecting a second catalyst system comprising an activator and another bis-cyclopentadienyl transition metal compound capable of producing a crystalline polypropylene having a Mw of less than 300,000 and a Mw/Mn of less than 3;

provided that the first and second catalyst systems are selected such that the Mw of the amorphous polypropylene is greater than the Mw of the crystalline polypropylene; and

contacting the first and second catalyst systems under polymerization conditions in a polymerization reactor with olefin monomers consisting essentially of propylene to produce a polypropylene composition comprising higher Mw amorphous polypropylene having a Mw of at least 150,000 and a Mw/Mn of less than 3 and lower Mw crystalline polypropylene having a Mw of less than 300,000 and a Mw/Mn of less than 3.

2. The process of claim 1, wherein the first catalyst system comprises a symmetrically substituted mono-cyclopentadienyl transition metal compound used in combination with an alumoxane or a compatible, non-coordinating anion activator;

and the second catalyst system comprises a bridged bis-cyclopentadienyl transition metal compound used in combination with an alumoxane or a compatible, non-coordinating anion activator.

3. The process of claim 1 wherein the transition metal compound of the first catalyst system is represented by the formula:

##STR7## where A'"'"' is a bridging Group;

(JS'"'"'_z-2) is a heteroatom ligand in which J is an element from Group 15 of the Periodic Table of Elements with a coordination number of 3 or an element from Group 16 with a coordination number of 2, S'"'"' is a radical Group which is a hydrocarbyl, substituted hydrocarbyl, halocarbyl, substituted halocarbyl, hydrocarbyl-substituted organometalloid, or halocarbyl-substituted organometalloid; and

z is the coordination number of the element J;

L'"'"' is an olefin, diolefin, aryne, amine, phosphine, ether, or sulfide ligand, or any other neutral Lewis base;

X₁ and X₂ are, independently, hydride radicals, hydrocarbyl radicals, substituted hydrocarbyl radicals, halocarbyl radicals, substituted halocarbyl radicals, and hydrocarbyl- and halocarbyl-substituted organometalloid radicals, substituted pnictogen radicals, or substituted chalcogen radicals;

or X₁ and X₂ are joined and bound to the metal atom to form a metallacycle ring containing from about 3 to about 20 carbon atoms;

or X₁ and X₂ together can be an olefin, diolefin or aryne ligand;

or when Lewis-acid activators which are capable of donating an X₁ ligand to the transition metal component are used, X₁ and X₂ may independently be a halogen, alkoxide, aryloxide, amide, phosphide or other univalent anionic ligand or both;

or X₁ and X₂ can also be joined to form a anionic chelating ligand provided that X₁ and X₂ are not a substituted or unsubstituted cyclopentadienyl ring;

z is the coordination number of the element J;

w is an integer from 0 to 3;

M is titanium;

S_v is a radical group which is a hydrocarbyl, substituted-hydrocarbyl, halocarbyl, substituted-halocarbyl, hydrocarbyl-substituted organometalloid, halocarbyl-substituted organometalloid, disubstituted boron, disubstituted pnictogen, substituted chalcogen or halogen radical where the subscript "v" denotes the carbon atom on the cyclopentadienyl ring to which the substituent is bonded and where there can be zero, two or four substituents, S, on the cyclopentadienyl ring, provided that the cyclopentadienyl ring is symmetrically substituted in the 2 and 5 positions and/or 3 and 4 positions with S groups that are within 2 carbons of each other.

4. The process of claim 1 wherein the second catalyst system is represented by the formula:

##STR8## wherein M is Ti, Zr or Hf;

"v" denotes the carbon atom on the Cp-ring to which the substituent is bonded;

each substituent Group S or S" is, independently, a radical group which is hydrocarbyl, substituted-hydrocarbyl, halocarbyl, substituted-halocarbyl, hydrocarbyl-substituted organometalloid, halocarbyl-substituted organometalloid, disubstituted boron, disubstituted pnictogen, substituted chalcogen or halogen radicals;

A'"'"' is a bridging Group;

X₁ and X₂ are, independently, hydride radicals, hydrocarbyl radicals, substituted hydrocarbyl radicals, halocarbyl radicals, substituted halocarbyl radicals, and hydrocarbyl- and halocarbyl-substituted organometalloid radicals, substituted pnictogen radicals, or substituted chalcogen radicals;

or X₁ and X₂ are joined and bound to the metal atom to form a metallacycle ring containing from about 3 to about 20 carbon atoms;

or X₁ and X₂ together can be an olefin, diolefin or aryne ligand;

or when Lewis-acid activators which are capable of donating an X₁ ligand to the transition metal component are used, X₁ and X₂ may independently be a halogen, alkoxide, aryloxide, amide, phosphide or other univalent anionic ligand or both X₁ and X₂ can also be joined to form a anionic chelating ligand and with the proviso that X₁ and X₂ are not a substituted or unsubstituted cyclopentadienyl ring.

5. The process of claim 1 wherein the first and second catalyst systems comprise one of the following combinations:

(1) Me₂ Si(Me₄ C₅)(N-c-C₁₂ H₂₃)TiCl₂ and Me₂ Si(H₄ Ind)₂ ZrCl₂ activated with an alumoxane;

(2) Me₂ Si(Me₄ C₅)(N-c-C₁₂ H₂₃)TiCl₂ and Me₂ Si(H₄ Ind)₂ HfCl₂ activated with an alumoxane;

(3) Me₂ Si(Me₄ C₅)(N-c-C₁₂ H₂₃)TiCl₂ and Me₂ Si(2-MeInd)₂ ZrCl₂ activated with an alumoxane;

(4) Me₂ Si(Me₄ C₅)(N-c-C₁₂ H₂₃)TiCl₂ and Me₂ Si(2-MeInd)₂ HfCl₂ activated with an alumoxane;

or

(5) Me₂ Si(Me₄ C₅)(N-c-C₁₂ H₂₃)TiCl₂ and Me₂ C(C₅ H₄)(1-fluorenyl)ZrCl₂ activated with an alumoxane.

6. The process of claim 5 wherein the alumoxane is methlyalumoxane.

7. The process of claim 1 wherein the first and second catalyst systems comprise one of the following combinations:

(1) Me₂ Si(Me₄ C₅)(N-c-C₁₂ H₂₃)TiMe₂ and Me₂ Si(H₄ Ind)₂ ZrMe₂ activated with a non-coordinating anion activator;

(2) Me₂ Si(Me₄ C₅)(N-c-C₁₂ H₂₃)TiMe₂ and Me₂ Si(H₄ Ind)₂ HfMe₂ activated with a non-coordinating anion activator;

(3) Me₂ Si(Me₄ C₅)(N-c-C₁₂ H₂₃)TiMe₂ and Me₂ Si(2-MeInd)₂ ZrMe₂ activated with a non-coordinating anion activator;

(4) Me₂ Si(Me₄ C₅)(N-c-C₁₂ H₂₃)TiMe₂ and Me₂ Si(2-MeInd)₂ HfMe₂ activated with a non-coordinating anion activator;

or

(5) Me₂ Si(Me₄ C₅)(N-c-C₁₂ H₂₃)TiMe₂ and Me₂ C(C₅ H₄)(1-fluorenyl)ZrMe₂ activated with a non-coordinating anion activator.

8. The process of claim 6 wherein the non-coordinating anion activator is N,N-dimethylanilinium tetrakis(pentaflourophenyl)boron or triphenylcarbonium tetrakis(pentaflourophenyl)boron.

9. The process of claim 1 wherein the amorphous polypropylene is a copolymer of propylene and another α

-olefin.

10. The process of claim 1 wherein the crystalline polypropylene is a copolymer of propylene and another α

-olefin.

11. The process of claim 1 wherein the transition metal compound of the first catalyst system is present at one to ten times the amount of the transition metal compound of the second catalyst system.

12. The process of claim 1 wherein the transition metal compound of the first catalyst system is present at about two to about four times the amount of the transition metal compound of the second catalyst system.