Very low creep, ultra high modulus, low shrink, high tenacity polyolefin fiber having good strength retention at high temperatures and method to produce such fiber

• US 5,958,582 A
• Filed: 04/20/1998
• Issued: 09/28/1999
• Est. Priority Date: 06/17/1985
• Status: Expired due to Fees

• Current Assignee: Alliedsignal Inc. (Honeywell International Inc.)
• Original Assignee: Alliedsignal Inc. (Honeywell International Inc.)
• Inventors: Dunbar, James Jay, Prevorsek, Dusan Ciril, Weedon, Gene Clyde, Wincklhofer, Robert Charles, Kavesh, Sheldon, Tam, Thomas Yiu-Tai
• Primary Examiner(s): Krynski, William
• Assistant Examiner(s): GRAY, JILL M
• Application Number:
  US09/064,664
• Time in Patent Office: 526 Days
• Field of Search: 428/364, 428/902, 428/394, 264/210.7, 264/210.8, 264/205, 264/290.5, 526/348.1, 521/108, 442/181, 442/327
• US Class Current: 428/364
• CPC Class Codes: D01F 6/04 from polyolefins
• CPC Class Codes: D07B 2205/2014 High performance polyolefins, e.g. Dyneema or Spectra
• CPC Class Codes: D07B 2401/2005 Elongation or elasticity
• CPC Class Codes: D07B 2801/10 Smallest filamentary entity of a rope or strand, i.e. wire, filament, fiber or yarn
• CPC Class Codes: Y10S 428/902 High modulus filament or fiber
• CPC Class Codes: Y10T 428/2913 Rod, strand, filament or fiber
• CPC Class Codes: Y10T 428/2967 Synthetic resin or polymer
• CPC Class Codes: Y10T 442/30 Woven fabric [i.e., woven strand or strip material]
• CPC Class Codes: Y10T 442/60 Nonwoven fabric [i.e., nonwoven strand or fiber material]

Abstract

By poststretching, at a temperature between about 135° and 160° C., a polyethylene fiber, which has already been oriented by drawing at a temperature within 5° C. of its melting point, an ultra high modulus, very low creep, low shrink, high tenacity polyolefin fiber having good strength retention at high temperatures is obtained. The poststretching can be in multiple stages and/or with previous annealing. The poststretching should be done at a draw rate of less than 1 second^-1. Tensile modulus values over 2,000 g/d for multifilament yarn are consistently obtained for ultrahigh molecular weight polyethylene, with tensile strength values above 30 g/d while at the same time dramatically improving creep (at 160° F. (71.1° C.) and 39,150 psi load) by values at least 25% lower than fiber which has not been poststretched. Shrinkage is improved to values less than 2.5% of the original length when heated from room temperature to 135° C. Performance at higher temperature is improved by about 15° to 25° C.

Claims

1. A low creep, high modulus, high strength, low shrink, high molecular weight polyolefin shaped article or fabric having improved strength retention at high temperatures which has been prepared by poststretching at a drawing rate of less than about 1 second^-1 at a temperature within about 10°

C. of its melting temperature, said shaped article or fabric, prior to being poststretched, being fabricated from polyolefin which has been highly oriented at a higher rate than 1 second^-1 and at a temperature of within about 10°

C. of its melting point.