Producing high tenacity, high modulus crystalline article such as fiber or film
First Claim
1. A process for producing a high strength, high modulus shaped thermoplastic article of substantially indefinite length which comprises the steps:
- (a) forming a solution of a thermoplastic crystalline polymer selected from the group consisting of polyethylene, polypropylene, polyoxymethylene, polybutene-1, poly(vinylidene fluoride) and poly(4-methylpentene-1) in a first, non-volatile solvent at a first concentration of about 2 to 15% by weight of polymer per unit weight of first solvent, said thermoplastic polymer having a weight average molecular length between about 7×
104 and about 71×
104 backbone atoms and the solubility of said thermoplastic polymer in said first solvent at a first temperature being at least said first concentration;
(b) extruding said solution through an aperture, said solution being at a temperature no less than said first temperature upstream of the aperture and being substantially at the first concentration both upstream and downstream of the aperture;
(c) cooling the solution adjacent to and downstream of the aperture to a second temperature below the temperature at which a gel is formed to form a gel containing first solvent of substantially indefinite length;
(d) extracting the gel containing first solvent with a second, volatile solvent for a sufficient contact time to form a gel containing second solvent which gel is substantially free of first solvent and is of substantially indefinite length;
(e) drying the gel containing second solvent to form a xerogel of substantially indefinite length free of first and second solvent; and
,(f) stretching at a sufficient temperature at least one of;
(i) the gel containing the first solvent,(ii) the gel containing the second solvent and,(iii) the xerogel at a total stretch ratio;
(i) in the case of polyethylene which is sufficient to achieve a tenacity of at least about 20 g/denier and a modulus of at least about 600 g/denier,(ii) in the case of polypropylene which is sufficient to achieve a tenacity of at least about 10 g/denier and a modulus of at least about 160 g/denier, and(iii) in the case of polyoxymethylene, polybutene-1, poly(vinylidene fluoride) or poly(4-methylpentene-1) of at least about 10;
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Accused Products
Abstract
Solutions of ultrahigh molecular weight polymers such as polyethylene in a relatively non-volatile solvent are extruded through an aperture at constant concentration through the aperture and cooled to form a first gel of indefinite length. 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. The first gel, second gel or xerogel, or a combination, are stretched. Among the products obtainable are polyethylene fibers of greater than 30 or even 40 g/denier tenacity and of modulus greater than 1000 or even 1600 or 2000 g/denier.
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Citations
30 Claims
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1. A process for producing a high strength, high modulus shaped thermoplastic article of substantially indefinite length which comprises the steps:
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(a) forming a solution of a thermoplastic crystalline polymer selected from the group consisting of polyethylene, polypropylene, polyoxymethylene, polybutene-1, poly(vinylidene fluoride) and poly(4-methylpentene-1) in a first, non-volatile solvent at a first concentration of about 2 to 15% by weight of polymer per unit weight of first solvent, said thermoplastic polymer having a weight average molecular length between about 7×
104 and about 71×
104 backbone atoms and the solubility of said thermoplastic polymer in said first solvent at a first temperature being at least said first concentration;(b) extruding said solution through an aperture, said solution being at a temperature no less than said first temperature upstream of the aperture and being substantially at the first concentration both upstream and downstream of the aperture; (c) cooling the solution adjacent to and downstream of the aperture to a second temperature below the temperature at which a gel is formed to form a gel containing first solvent of substantially indefinite length; (d) extracting the gel containing first solvent with a second, volatile solvent for a sufficient contact time to form a gel containing second solvent which gel is substantially free of first solvent and is of substantially indefinite length; (e) drying the gel containing second solvent to form a xerogel of substantially indefinite length free of first and second solvent; and
,(f) stretching at a sufficient temperature at least one of; (i) the gel containing the first solvent, (ii) the gel containing the second solvent and, (iii) the xerogel at a total stretch ratio; (i) in the case of polyethylene which is sufficient to achieve a tenacity of at least about 20 g/denier and a modulus of at least about 600 g/denier, (ii) in the case of polypropylene which is sufficient to achieve a tenacity of at least about 10 g/denier and a modulus of at least about 160 g/denier, and (iii) in the case of polyoxymethylene, polybutene-1, poly(vinylidene fluoride) or poly(4-methylpentene-1) of at least about 10;
1. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A process for producing a high strength, high modulus shaped thermoplastic article of substantially indefinite length which comprises the steps:
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(a) forming a solution of a thermoplastic crystalline polymer selected from the group consisting of polyethylene, polypropylene, polyoxymethylene, polybutene-1, poly(vinylidene fluoride) and poly(4-methylpentene-1) in a first, non-volatile solvent at a first concentration between about 2 and 15% by weight of polymer per unit weight of first solvent, said thermoplastic polymer having a weight average molecular length between about 7×
104 and about 71×
104 backbone atoms and the solubility of said thermoplastic polymer in said first solvent at a first temperature being at least said first concentration;(b) extruding said solution through an aperture, said solution being at a temperature no less than said first temperature upstream of the aperture and being substantially at the first concentration both upstream and downstream of the aperture; (c) cooling the solution adjacent to and downstream of the aperture to a second temperature below the temperature at which a gel is formed, forming a gel containing first solvent of substantially indefinite length; (d) extracting the gel containing first solvent with a second, volatile solvent for a sufficient contact time to form a gel containing second solvent which gel is substantially free of first solvent and is of substantially indefinite length; (e) stretching at a sufficient temperature at least one of; (i) the gel containing the first solvent, and (ii) the gel containing the second solvent, (f) drying the gel containing second solvent to form a xerogel of substantially indefinite length free of first and second solvent, which (i) in the case of polyethylene has a tenacity of at least about 20 g/denier and a modulus of at least about 600 g/denier, (ii) in the case of polypropylene has a tenacity of at least about 10 g/denier and a modulus of at least about 160 g/denier, and (iii) in the case of polyoxymethylene, polybutene-1, poly(venylidene fluoride) or poly(4-methylpentene-1) been stretched at a ratio of at least about 10;
1. - View Dependent Claims (14, 15, 16, 17, 18)
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19. A process for producing a high strength, high modulus shaped thermoplastic article of substantially indefinite length which comprises the steps:
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(a) forming a solution of a thermoplastic crystalline polymer selected from the group consisting of polyethylene and polypropylene in a first, nonvolatile solvent at a first concentration of between about 4 and 10% by weight of polymer per unit weight of first solvent, said thermoplastic polymer having a weight average molecular length between about 7×
104 and about 71×
104 backbone atoms and the solubility of said thermoplastic polymer in said first solvent at a first temperature being at least said first concentration;(b) extruding said solution through an aperture, said solution being at a temperature no less than said first temperature upstream of the aperture and being substantially at the first concentration both upstream and downstream of the aperture; (c) cooling the solution adjacent to and downstream of the aperture to a second temperature below the temperature at which a rubbery gel is formed, forming a gel containing first solvent of substantially indefinite length; (d) extracting the gel containing first solvent with a second, volatile solvent for a sufficient contact time to form a gel containing second solvent which gel is substantially free of first solvent and is of substantially indefinite length; (e) stretching at a sufficient temperature at least one of; (i) the gel containing the first solvent, and (ii) the gel containing the second solvent; and (f) drying the gel containing second solvent to form a xerogel of substantially indefinite length free of first and second solvent, and (i) in the case of polyethylene a tenacity of at least about 30 g/denier and/or a modulus of at least about 1000 g/denier, and (ii) in the case of polypropylene a tenacity of at least about 10 g/denier and a modulus of at least about 160 g/denier. - View Dependent Claims (20, 21)
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22. A process for producing a high strength, high modulus shaped polyethylene article of substantially indefinite length which comprises the steps:
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(a) forming a solution of polyethylene in a first, nonvolatile solvent at a first concentration of about 2 to 15 percent by weight of polymer per unit weight of first solvent, said polyethylene having a weight average molecular weight between about one million and about ten million and the solubility of said polyethylene in said first solvent at a first temperature being at least said first concentration; (b) extruding said solution through an aperture, said solution being at a temperature no less than said first temperature upstream of the aperture and being substantially at the first concentration both upstream and downstream of the aperture; (c) cooling the solution adjacent to and downstream of the aperture to a second temperature below the temperature which rubbery gel is formed, including quenching in a quench bath, forming a gel containing first solvent of substantially indefinite length; (d) extracting the gel containing first solvent with a second, volatile solvent for a sufficient contact time to form a gel containing second solvent which gel is substantially free of first solvent and is of substantially indefinite length; (e) stretching at a sufficient temperature at least one of; (i) the gel containing the first solvent, and (ii) the gel containing the second solvent; and (f) drying the gel containing second solvent to form a xerogel of substantially indefinite length free of first and second solvent the xerogel having a tenacity of at least about 20 g/denier, and a modulus of at least about 600 g/denier. - View Dependent Claims (23, 24, 25)
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26. A process for producing a high strength, high modulus shaped polyethylene article of substantially indefinite length which comprises the steps:
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(a) forming a solution of polyethylene in a first, nonvolatile solvent at a first concentration of about 2 to 15 percent by weight of polymer per unit weight of first solvent, said polyethylene having a weight average molecular weight between about one million and about ten million and the solubility of said polyethylene in said first solvent at a first temperature being at least said first concentration; (b) extruding said solution through an aperture, said solution being at a temperature no less than said first temperature upstream of the aperture and being substantially at the first concentration both upstream and downstream of the aperture; (c) cooling the solution adjacent to and downstream of aperture to a second temperature below the temperature which rubbery gel is formed, including quenching in a quench bath, forming a gel containing first solvent of substantially indefinite length; (d) extracting the gel containing first solvent with a second, volatile solvent for a sufficient contact time to form a gel containing second solvent which gel is substantially free of first solvent and is of substantially indefinite length; (e) drying the gel containing second solvent to form a xerogel of substantially indefinite length free of first and second solvent, which xerogel has a pore volume less than about 10%; and (f) stretching at a sufficient temperature at least one of; (i) the gel containing the first solvent, (ii) the gel containing the second solvent and, (iii) the xerogel, at a total stretch ratio which is sufficient to achieve a tenacity of at least about 20 g/denier and a modulus of at least about 600 g/denier. - View Dependent Claims (27, 28, 29)
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30. A process for producing a high strength, high modulus shaped polyethylene article of substantially indefinite length which comprises the steps:
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(a) forming a solution of polyethylene in a first, novolatile solvent at a first concentration of between about 2 and about 15% by weight of polymer per unit weight of first solvent, said polyethylene having a weight average molecular weight between about one million and about ten million and the solubility of said polyethylene in said first solvent at a first temperature being at least said first concentration; (b) extruding said solution through an aperture, said solution being at a temperature no less than said first temperature upstream of the aperture and being substantially at the first concentration both upstream and downstream of the aperture; (c) cooling the solution adjacent to and downstream of the aperture to a second temperature below the temperature which rubbery gel is formed, including quenching in a quench bath, forming a gel containing first solvent of substantially indefinite length; (d) extracting the gel containing first solvent with a second, volatile solvent for a sufficient contact time to form a gel containing second solvent which gel is substantially free of first solvent and is of substantially indefinite length; (e) stretching at a sufficient temperature at least one of; (i) the gel containing the first solvent, (ii) the gel containing the second solvent; (f) drying the gel containing second solvent to form a xerogel of substantially indefinite length free of first and second solvent having a pore volume less than about 10%; (g) stretching to xerogel to produce a stretched polyethylene article having a tenacity of at least about 20 g/denier and a modulus of at least about 1000 g/denier.
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Specification