Polypropylene impact copolymers with low haze

Patent metadata

Field	Value
Publication number	US-10808111-B2
Application number	US-201414773976-A
Country	US
Kind code	B2
Filing date	Mar 13, 2014
Priority date	Mar 14, 2013
Publication date	Oct 20, 2020
Grant date	Oct 20, 2020

Abstract

The present invention provides an in-reactor solution that avoids costly blending and the use of metallocene elastomers. The inventive Ziegler-Natta polypropylene composition also includes additional components that may improve properties relative to a metallocene catalyzed elastomers. The invention is a clear impact polypropylene composition that is made in-reactor with Ziegler-Natta catalyst, and is suitable for a wide range of processes. Unlike other clear impact copolymers, it does not rely on high-shear processes or compounding with elastomers. The invention uses conventional polypropylene reactor technology to produce these compositions.

First claim

The invention claimed is:

1. A propylene impact copolymer comprising: (a) a matrix comprising a polypropylene homopolymer or a propylene/alpha-olefin random copolymer which comprises more than 50 wt. % of units derived from propylene monomer; and (b) a dispersed phase comprising an ethylene-propylene copolymer, wherein the dispersed phase has a melting point between 100° C. and 124° C., and an enthalpy greater than 11 J/g, the dispersed phase having a molar ratio of ethylene moiety/(ethylene moiety plus propylene moiety) greater than 0.82, wherein the propylene impact copolymer has a haze value less than 30% in a 50 mil plaque, and a haze value less than 15% in a 20 mil plaque.

2. The propylene impact copolymer of claim 1 , having a Gardner impact value greater than 200 in-lbs.

3. The propylene impact copolymer of claim 1 , catalyzed with a Ziegler-Natta catalyst.

4. The propylene impact copolymer of claim 1 , having 10 wt. % or less xylene solubles.

5. A manufactured article comprising (a) a matrix comprising a polypropylene homopolymer or a propylene/alpha-olefin random copolymer which comprises more than 50 wt. % of units derived from propylene monomer; and (b) a dispersed phase comprising an ethylene-propylene copolymer, wherein the dispersed phase has a melting point between 100° C. and 124° C., and an enthalpy greater than 11 J/g, the dispersed phase having a molar ratio of ethylene moiety/(ethylene moiety plus propylene moiety) greater than 0.82, wherein the manufactured article has a haze value less than 30% in a 50 mil plaque, and a haze value less than 15% in a 20 mil plaque.

6. The manufactured article of claim 5 , catalyzed with a Ziegler-Natta catalyst.

7. The manufactured article of claim 5 is a thermoformed container.

8. The manufactured article of claim 5 is a blow molded container.

9. The manufactured article of claim 5 is an injection molded container.

10. A process to produce a propylene impact copolymer comprising the steps of: (a) one or more matrix phase polymerization steps, occurring in one or more liquid phase reactors; (b) one or more dispersed phase polymerization steps, occurring in one or more gas phase reactors; and (c) at least one de-gassing step, the propylene impact copolymer comprising: ( 1 ) a matrix comprising a polypropylene homopolymer or a propylene/alpha-olefin random copolymer which comprises more than 50 wt.% of units derived from propylene monomer; and ( 2 ) a dispersed phase comprising an ethylene-propylene copolymer, wherein the dispersed phase has a melting point between 100 ° C. and 124 ° C., and an enthalpy greater than 11 J/g, the dispersed phase having a molar ratio of ethylene moiety/(ethylene moiety plus propylene moiety) greater than 0.82, wherein the propylene impact copolymer has a haze value less than 30% in a 50 mil plaque, and a haze value less than 15% in a 20 mil plaque.

11. The propylene impact copolymer produced by the process of claim 10 , having a Gardner impact value greater than 200 in-lbs.

12. The propylene impact copolymer produced by the process of claim 10 , catalyzed with a Ziegler-Natta catalyst.

Assignees

• Braskem America Inc

Inventors

• Dias Peter Simon
• Meverden Craig Charles
• Catalina Edward E
• Cuthbert Thomas
• Majewski Rita
• Wilson Debra R

Classifications

• B29C49/0691

  using sheet like material, e.g. sheet blow-moulding from joined sheets · CPC title

• B29C49/22

  using multilayered preforms or parisons · CPC title

• B32B27/30 Primary

  comprising vinyl {(co)polymers; comprising acrylic (co)polymers} · CPC title

• B29C49/0685

  Compression blow-moulding · CPC title

• B32B2270/00

  Resin or rubber layer containing a blend of at least two different polymers · CPC title