Pelletizing aid for polymers

• US 5,623,012 A
• Filed: 12/19/1995
• Issued: 04/22/1997
• Est. Priority Date: 12/19/1995
• Status: Expired due to Fees

• Current Assignee: Shell Oil Company (Shell Plc)
• Original Assignee: Shell Oil Company (Shell Plc)
• Inventors: Hwo, Charles C.
• Primary Examiner(s): Szekely, Peter A.
• Application Number:
  US08/574,805
• Time in Patent Office: 490 Days
• Field of Search: 524/394, 524/398, 524/399, 524/400
• US Class Current: 524/398
• CPC Class Codes: C08J 2323/20 having four to nine carbon atoms
• CPC Class Codes: C08J 3/124 Treatment for improving the free-flowing characteristics

Abstract

The addition of a synergistic pelletizing aid package of HDPE and metallic fatty acid surfactant to the water bath to minimize the agglomeration of polyolefin pellets in an underwater pelletizing process.

Claims

1. A method for minimizing the agglomeration of freshly manufactured polyolefin pellets comprising adding an effective amount of pelletizing aid package consisting essentially of a high density polyethylene and a fatty acid metallic surfactant to a device comprising a cooling agent and said freshly prepared pellets during the manufacturing of said pellets.

2. The method as described in claim 1, wherein said cooling agent is water.

3. The method as described in claim 1, wherein said polyolefin pellets are high melt flow polyolefin pellets.

4. The method as described in claim 1, wherein said polyolefin pellets are poly-1-butene homopolymer or poly-1-butene copolymer pellets.

5. The method as described in claim 1, wherein said polyolefin pellets are high melt flow poly-1-butene-ethylene copolymer pellets.

6. The method as described in claim 1, wherein said high density polyethylene has a density of above 0.93 g/cc at 25°

C.

7. The method as described in claim 6, wherein said fatty acid metallic surfactant is a metal salt of a fatty acid having 12 to 22 carbon atoms, wherein said metal of the metal salt is selected from the group consisting of Group IA metal, Group IIA metal, aluminum, zinc, and cadmium (Cd).

8. The method as described in claim 7, wherein said fatty acid metallic surfactant is selected from the group consisting of zinc stearate, zinc oleate, aluminum stearate, aluminum oleate, calcium stearate, calcium oleate, lithium stearate, lithium oleate, sodium stearate, and sodium oleate.

9. The method as described in claim 7, wherein said polyolefin polymer is butene-1-ethylene copolymer.

10. The method as described in claim 5, wherein said butene-1-ethylene copolymer contains from about 0.1 to 8 wt % ethylene.

11. The method as described in claim 1 wherein said fatty acid metallic surfactant is added in an amount of from about 0.01 to about 0.6 wt % of said cooling agent, and said high density polyethylene is added in an amount of from about 0.03 to about 1.0 wt % of said cooling agent.

12. The method as described in claim 1 wherein said fatty acid metallic surfactant is added in an amount of from about 0.07 to about 0.2 wt % of said cooling agent, and said high density polyethylene is added in an amount of from about 0.09 to about 0.4 wt % of said cooling agent.

13. A poly-1-butene pellet product made by a method effective for minimizing the agglomeration of freshly manufactured poly-1-butene homo- or copolymer pellets, which method comprising adding an effective amount of pelletizing aid package consisting essentially of a high density polyethylene and a fatty acid metallic surfactant to a device comprising a cooling agent and said freshly prepared pellets during the manufacturing of said pellets.