LBT process of making high-tenacity polyethylene fiber

• US 5,547,626 A
• Filed: 06/07/1995
• Issued: 08/20/1996
• Est. Priority Date: 12/16/1993
• Status: Expired due to Term

• Current Assignee: Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Original Assignee: Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Inventors: Oie, Yoshinobu, Ohta, Yasuo, Kuroki, Tadao
• Primary Examiner(s): Tentoni, Leo B.
• Application Number:
  US08/478,804
• Time in Patent Office: 440 Days
• Field of Search: 264/203, 264/205, 264/210.7, 264/210.8
• US Class Current: 264/203
• CPC Class Codes: C08F 110/02 Ethene
• CPC Class Codes: C08F 2500/10 Short chain branches
• CPC Class Codes: C08F 2500/17 Viscosity
• CPC Class Codes: D01F 6/04 from polyolefins
• CPC Class Codes: Y10T 428/2913 Rod, strand, filament or fiber
• CPC Class Codes: Y10T 428/2967 Synthetic resin or polymer

Abstract

There is disclosed a high-tenacity polyethylene fiber containing an ethylene component as a main repeating unit, the fiber exhibiting an intrinsic viscosity [η_B ] of at least 7 and having a tenacity of at least 30 g/d and an elastic modulus of at least 900 g/d; the peak value of loss tangent in the γ-dispersion being 0.025 to 0.06 and the peak temperature of loss modulus in the α-dispersion being 85° C. or higher, as determined by measurement of temperature dispersion of viscoelastic properties of the fiber. Also disclosed is a process of producing such a high-tenacity polyethylene fiber.

Claims

1. A process of producing a high-tenacity polyethylene fiber, comprising the steps of:

mixing an ultrahigh-molecular-weight polyethylene exhibiting an intrinsic viscosity [η

_A ] of at least 10 and a solvent with heating for dissolution, the weight ratio of the polyethylene to the solvent being in the range of 5;

95 to 50;

50;

extruding the mixture and cooling the extrudate to form a semi-finished fiber; and

stretching the semi-finished fiber at a ratio of at least 10 times to form a finished fiber exhibiting an intrinsic viscosity [η

_B ] of at least 7 and having a tenacity of at least 30 g/d and an elastic modulus of at least 900 g/d, the intrinsic viscosities [η

_A ] and [η

_B ] complying with the following relationship;

space="preserve" listing-type="equation">0.7×

[η

.sub.A ]≦

[η

.sub.B ]≦

0.9×

[η

.sub.A ].

2. A process according to claim 1, wherein the semi-finished fiber is subjected to pre-stretching at a temperature of 130°

C. or lower before the stretching.

3. A process according to claim 2, wherein the pre-stretching is conducted at a temperature of 120°

C. to room temperature.

4. A process according to claim 1, wherein the intrinsic viscosities [η

_A ] and [η

_B ] comply with the following relationship;

space="preserve" listing-type="equation">0.75×

[η

.sub.A ]≦

[η

.sub.B ]≦

0.85×

[η

.sub.A ].