Polypropylene for reduced plate out in polymer article production processes

Patent metadata

Field	Value
Publication number	US-9718903-B2
Application number	US-201615093390-A
Country	US
Kind code	B2
Filing date	Apr 7, 2016
Priority date	Oct 1, 2008
Publication date	Aug 1, 2017
Grant date	Aug 1, 2017

Abstract

Polymer articles and processes of forming polymer articles are described herein. The processes generally include providing a propylene based polymer formed from a metallocene catalyst and melt processing the propylene based polymer to form a polymer article.

First claim

What is claimed is:

1. A process of forming molded polymer articles comprising:
selecting one or more propylene based polymers formed from a metallocene catalyst;
providing the one or more propylene based polymers;
melt processing by blow molding the one or more propylene based polymers at a barrel temperature of at least 420° F. and a hot runner temperature of at least 480° F. for at least about 30 hours to form blow molded polymer articles therefrom without experiencing plate-out or blooming in the blow molded polymer articles, wherein the propylene based polymers comprises an ethylene content of less than 5 weight percent and less than 5 weight percent of xylene solubles; and;
heat treating the blow molded polymer articles, wherein the heat treating comprises heating the blow molded polymer articles at a temperature of at least about 120° C for a time of at least about 30 minutes, wherein the blow molded polymer articles exhibit a haze reduced by at least 20% in comparison to prior to the heat treating.

2. The process of claim 1 , further comprising sterilizing the molded polymer article, wherein the molded polymer article at least maintains haze upon heat treating at 120° C. for 30 minutes.

3. The process of claim 1 , wherein the propylene based polymer comprises less than about 5 wt. % xylene solubles.

4. The process of claim 1 , wherein the blow molding of the propylene based polymers is performed at a barrel temperature of at least 420° F. and a hot runner temperature of at least 480° F. for at least 100 hours without experiencing plate-out or blooming in the blow molded polymer articles.

5. The process of claim 1 , wherein the melt processing occurs at a temperature of at least about 110° C.

6. The process of claim 1 , further comprising contacting the propylene based polymers with an additive selected from the group consisting of: antistatic agents, slip agents, clarifiers, nucleators, hindered amine light stabilizers and combinations thereof.

7. The process of claim 1 , further comprising contacting the propylene based polymers with a slip agent, wherein the propylene based polymer is contacted with less than 100 ppm of the slip agent.

8. The process of claim 1 , wherein the propylene based polymers comprise a polypropylene homopolymer or a random copolymer of propylene and ethylene.

9. The process of claim 1 , wherein the propylene based polymers exhibit a molecular weight distribution of from about 1.5 to about 12.

10. The process of claim 1 , wherein the propylene based polymers exhibit a melt flow rate of from about 15 dg/min. to about 100 dg/min.

Assignees

• Fina Technology

Inventors

• Patkar Mahesh
• Musgrave Michael
• Thierry-Mieg Jerome
• Sun Luyi
• Sun Likuo

Classifications

• B29C49/0005

  characterised by the material · CPC title

• B29C71/0072

  for changing orientation · CPC title

• C08F110/06 Primary

  Propene · CPC title

• C08F210/06

  Propene · CPC title

• C08F2500/12

  Melt flow index or melt flow ratio · CPC title