Shaped polyethylene articles of intermediate molecular weight and high modulus

• US 5,972,498 A
• Filed: 03/23/1998
• Issued: 10/26/1999
• Est. Priority Date: 01/11/1985
• Status: Expired due to Fees

• Current Assignee: Alliedsignal Inc.
• Original Assignee: Alliedsignal Inc.
• Inventors: Kavesh, Sheldon, Prevorsek, Dusan Ciril
• Primary Examiner(s): Krynski, William
• Assistant Examiner(s): Gray, Jill M.
• Application Number:
  US09/046,317
• Time in Patent Office: 582 Days
• Field of Search: 428/364, 428/369, 428/359, 428/394, 428/500, 526/348.1
• US Class Current: 428/364
• CPC Class Codes: B29C 48/022 characterised by the choice of material
• CPC Class Codes: B29C 48/05 Filamentary, e.g. strands
• CPC Class Codes: B29C 48/08 flexible, e.g. films
• CPC Class Codes: B29K 2023/06 PE, i.e. polyethylene
• CPC Class Codes: B29K 2105/0061 Gel or sol
• CPC Class Codes: B29K 2223/06 PE, i.e. polyethylene
• CPC Class Codes: B29K 2995/0088 Molecular weight
• CPC Class Codes: C08J 2323/06 Polyethene
• CPC Class Codes: C08J 5/18 Manufacture of films or sheets
• CPC Class Codes: D01D 5/00 Formation of filaments, threads, or the like
• CPC Class Codes: D01F 6/04 from polyolefins
• CPC Class Codes: D07B 1/02 Ropes built-up from fibrous or filamentary material, e.g. of vegetable origin, of animal origin, regenerated cellulose, plastics
• CPC Class Codes: D07B 1/025 comprising high modulus, or high tenacity, polymer filaments or fibres, e.g. liquid-crystal polymers
• CPC Class Codes: D07B 2205/2014 High performance polyolefins, e.g. Dyneema or Spectra
• CPC Class Codes: D07B 2801/10 Smallest filamentary entity of a rope or strand, i.e. wire, filament, fiber or yarn
• CPC Class Codes: D10B 2321/0211 high-strength or high-molecular-weight polyethylene, e.g. ultra-high molecular weight polyethylene [UHMWPE]
• 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 428/31855 Of addition polymer from unsaturated monomers

Abstract

Solutions of intermediate molecular weight polymers from about 200,000 to about 4,000,000, such as polyethylene, in a relatively non-volatile solvent are extruded through an aperature at constant concentration and thereafter stretched at a ratio of at least about 3:1 prior to cooling to form a first gel. The first gels are extracted with a volatile solvent to form a second gel, and the second gel is dried to form a low porosity xerogel. Stretching occurs with any one or more of the first gel, second gel or xerogel. The polyethylene products produced by our process include products having a molecular weight between about 200,000 and about 4,000,000 a tenacity of at least about 13 grams/denier, a modulus of at least about 350 gram/denier, a porosity of less than 10% by volume, a crystalline orientation function of at least about 0.95, and a main melting temperature of at least about 140° C.

Claims

1. A composite article comprising polyethylene film or fiber having a weight average molecular weight between 200,000 and 4,000,000 kg/kg mole, a tensile modulus of at least 350 g/d, a tenacity of at least 13 g/d, a crystalline orientation function of at least 0.95, and a main melting temperature of at least 140°

C. (measured at 10°

C. per minute heating rate by differential scanning calorimetry), and subjected to solution stretching at a ratio of at least 3;

1.

2. A composite article comprising polyethylene film or fiber having a weight average molecular weight between 200,000 and 4,000,000 kg/kg mole, a tensile modulus of at least 350 g/d, a tenacity of at least 13 g/d, a crystalline orientation function of at least 0.95, a main melting temperature of at least 140°

C. (measured at 10°

C./minute heating rate by differential scanning calorimetry), an ultimate elongation of not more than 5%, and a transverse microfibrillar spacing of less than 150 Å

.