High tenacity polyethylene yarn

• US 7,736,561 B2
• Filed: 10/21/2009
• Issued: 06/15/2010
• Est. Priority Date: 06/08/2007
• Status: Expired due to Fees

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Twomey, Conor, Young, John A., Zhou, Qiang, Arnett, Charles R., Tam, Thomas Y-T.
• Primary Examiner(s): EDWARDS, NEWTON O
• Application Number:
  US12/589,285
• Publication Number:
  US 20100065982A1
• Time in Patent Office: 237 Days
• Field of Search: 264/176.1, 264/178.F, 264/46.1, 264/213, 264/204, 264/210.7, 264/210.8, 526/352, 526/348.1
• US Class Current: 264/178.00F
• CPC Class Codes: B29C 2948/9259 Angular velocity
• CPC Class Codes: B29C 2948/92952 Drive section, e.g. gearbox, motor or drive fluids
• CPC Class Codes: B29C 48/05 Filamentary, e.g. strands
• CPC Class Codes: B29C 48/405 Intermeshing co-rotating screws
• CPC Class Codes: B29K 2023/0683 UHMWPE, i.e. ultra high molecular weight polyethylene
• CPC Class Codes: D01D 1/02 Preparation of spinning solutions
• CPC Class Codes: D01D 5/06 Wet spinning methods D01D5/0046 takes precedence
• CPC Class Codes: D01F 1/10 Other agents for modifying properties
• CPC Class Codes: D01F 6/04 from polyolefins
• CPC Class Codes: Y10T 428/2913 Rod, strand, filament or fiber
• CPC Class Codes: Y10T 428/2931 Fibers or filaments nonconcentric [e.g., side-by-side or eccentric, etc.]
• CPC Class Codes: Y10T 428/2967 Synthetic resin or polymer

Abstract

A process for preparing ultra-high molecular weight polyethylene (UHMWPE) multi-filament yarns having improved tensile properties and the yarns and articles thereby produced.

Claims

1. A process of producing a high strength polyethylene multi-filament yarn comprising the steps of:

a) forming a slurry of an ultrahigh molecular weight polyethylene (UHMWPE) having an initial intrinsic viscosity (IV₀) at least about 10 dl/g and an antioxidant in a solvent for said UHMWPE having an atmospheric pressure boiling point at least about 180°

C. at a temperature that is below the temperature at which the UHMWPE will dissolve in said solvent, the weight ratio of said UHMWPE to said solvent being from about 5;

95 to about 95;

5 and the weight ratio of said antioxidant to said solvent being from about 10 parts per million to about 1000 parts per million;

b) feeding said slurry to an intermeshing co-rotating twin screw extruder wherein the screws in said twin screw extruder are comprised of multiple segments having a root diameter of D_r millimeters, an outside diameter of D_o millimeters, the ratio D_r/D_o is R, the rotational speed of the screws is ω

revolutions per minute and following relationships are satisfied

2. The process of claim 1, wherein said antioxidant is selected from the group consisting of tetrakis[methylene(3,5-di-ter-butylhydroxyhydrocinnamate)]methane, tris(2,4-di-tert-butylphenyl) phosphite, octadecyl 3,5-di-tert-butyl-4-hyroxyhydrocinnamate, 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6 (1H,3H,5H)-trione, 2,5,7,8 tetramethyl-2(4′

,8′

,12′

-trimethyltridecyl)chroman-6-ol, α

-tocopherol, and their mixtures.

3. The process of claim 1, wherein the weight ratio of said antioxidant to said solvent is from about 10 parts per million to about 100 parts per million.

4. The process of claim 1, wherein said twin screw extruder is run liquid full with the extruder feed zone flooded with said slurry under an inert gas blanket.

5. The process of claim 1, wherein the average residence time of said liquid mixture in said twin screw extruder is not more than about 1.5 minutes.

6. The process of claim 1 wherein substantially all of said screw segments in said twin screw extruder are forwarding conveying flight segments.

7. The process of claim 1, wherein the temperature of the mixture exiting said twin screw extruder is from about 220°

C. to about 320°

C.

8. The process of claim 1, wherein the liquid in said liquid quench bath is selected from the group consisting of water, ethylene glycol, ethanol, iso-propanol, a water soluble anti-freeze and their mixtures, and wherein said liquid quench bath temperature is from about minus 35°

C. to about 35°

C.

9. The process of claim 1, wherein said high strength multi-filament yarn comprises at least about 100 filaments.

10. The process of claim 9, wherein said high strength multi-filament yarn has an intrinsic viscosity less than or equal to about 18 dl/g.