Patent US4303606A successfully refreshed from Google Patents.
US4303606A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of extruding polypropylene yarn
Assignee: Kling-Tecs Inc
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Filing: 1980-03-15
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Granted: 1981-12-01
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Expires: 2000-03-15
Abstract
Abstract A method of extruding multi-filament polypropylene yarn in which the polypropylene is extruded at a temperature below 425° F., such as in the range 415° F. to 350° F., particularly about 400° F., into a hot zone having a temperature sufficiently high to retard cooling of the extruded polypropylene yarn. The temperature of the hot zone can be within 60° F. of the temperature of extrusion. The yarn is then passed through a quenching zone across which air is blown to cool the yarn. The swell value of the polypropylene can be less than 3 and its melt flow may be greater than 30. The yarn is drawn down in the hot zone and the filaments may be drawn down to an undrawn denier of less than 40.
Inventors
- 👤 John S. Roberts
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 16:34
CPC Classifications
D; D01; D01F; D01F6/00; D01F6/02; D01F6/04; D01F6/06; D01D; D01D5/00; D01D5/08; D01D5/084
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
142 words
A method of producing polypropylene filaments, comprising heating polypropylene having a narrow molecular weight distribution with a swell value of less than 2.5 and a melt flow greater than 20 to a temperature at which it is molten, extruding the molten polypropylene at a temperature in the range 415° F. to 350° F. into a plurality of filaments, passing the filaments through a hot zone having a temperature sufficiently high to retard cooling of the filaments therein, drawing down the filaments in said hot zone, then passing the filaments through a quenching zone, and directing gas over the filaments in said quenching zone to cool them, the characteristics of the polypropylene, the temperature of extrusion, and the temperature of said hot zone interacting to substantially eliminate the occurrence of resonance in the filaments as they are drawn down in said hot zone.
Claim 2
Independent Claim
142 words
A method of producing polypropylene filaments, comprising heating polypropylene having a narrow molecular weight distribution with a swell value of less than 2.5 and a melt flow greater than 20 to a temperature at which it is molten, extruding the molten polypropylene at a temperature in the range 415° F. to 350° F. into a plurality of filaments, passing the filaments through a hot zone having a temperature sufficiently high to retard cooling of the filaments therein, drawing down the filaments in said hot zone, then passing the filaments through a quenching zone, and directing gas over the filaments in said quenching zone to cool them, the characteristics of the polypropylene, the temperature of extrusion, and the temperature of said hot zone interacting to substantially eliminate the occurrence of resonance in the filaments as they are drawn down in said hot zone.
Claim 3
Dependent Claim
24 words
The method recited in claim 1, in which said molten polypropylene is extruded at a temperature in the range 410° F. to 360° F.
Claim 4
Dependent Claim
14 words
The method recited in claim 2, in which said extrusion temperature is 400° F.
Claim 5
Dependent Claim
15 words
The method recited in claim 1, in which said swell value is less than 2.0.
Claim 6
Dependent Claim
18 words
The method recited in claim 4, in which said swell value is in the range 1.2 to 1.7.
Claim 7
Dependent Claim
18 words
The method recited in claim 5, in which said melt flow is in the range 35 to 45.
Claim 8
Dependent Claim
23 words
The method recited in claim 1, in which said gas comprises air and is blown transversely across said filaments and exhausted to atmosphere.
Claim 9
Dependent Claim
24 words
The method recited in claim 7, in which the temperature of said air as it enters said quenching zone is less than 90° F.
Claim 10
Dependent Claim
36 words
The method of producing filaments recited in claim 1, in which said filaments are produced as multifilament yarns, and further comprising the steps of winding said yarns onto separate packages, and subsequently multi-end drawing said yarns.
Claim 11
Dependent Claim
16 words
The method recited in claim 9, in which said multi-end drawing comprises drawing eight yarns together.
Claim 12
Independent Claim
122 words
A method of producing polypropylene filaments, comprising heating polypropylene having a narrow molecular weight distribution to a temperature at which it is molten, extruding the molten polypropylene at a temperature below 425° F. into a plurality of filaments, passing the filaments through a hot zone having a temperature sufficiently high to retard cooling of the filaments therein, drawing down the filaments in said hot zone, then passing the filaments through a quenching zone, and directing gas over the filaments in said quenching zone to cool them, the characteristics of the polypropylene, the temperature of extrusion, and the temperature of said hot zone interacting to substantially eliminate the occurrence of resonance in the filaments as they are drawn down in said hot zone.
Claim 13
Independent Claim
122 words
A method of producing polypropylene filaments, comprising heating polypropylene having a narrow molecular weight distribution to a temperature at which it is molten, extruding the molten polypropylene at a temperature below 425° F. into a plurality of filaments, passing the filaments through a hot zone having a temperature sufficiently high to retard cooling of the filaments therein, drawing down the filaments in said hot zone, then passing the filaments through a quenching zone, and directing gas over the filaments in said quenching zone to cool them, the characteristics of the polypropylene, the temperature of extrusion, and the temperature of said hot zone interacting to substantially eliminate the occurrence of resonance in the filaments as they are drawn down in said hot zone.
Claim 14
Independent Claim
128 words
A method of producing polypropylene filaments, comprising heating polypropylene to a temperature at which it is molten, extruding the molten polypropylene at a temperature below 425° F. into a plurality of filaments, passing the filaments through a relatively short hot zone containing gas in a quiescent state at a temperature sufficiently high to retard cooling of the filaments therein and drawing down the filaments to their undrawn denier while in said hot zone, followed thereafter by cooling the drawn down filaments by passing them through a quenching zone and directing cooling gas over them to cool them therein, the low temperature of extrusion, the characteristics of said hot zone, and said drawing down in said hot zone interacting to substantially eliminate the occurrence of resonance in the filaments.
Claim 15
Independent Claim
128 words
A method of producing polypropylene filaments, comprising heating polypropylene to a temperature at which it is molten, extruding the molten polypropylene at a temperature below 425° F. into a plurality of filaments, passing the filaments through a relatively short hot zone containing gas in a quiescent state at a temperature sufficiently high to retard cooling of the filaments therein and drawing down the filaments to their undrawn denier while in said hot zone, followed thereafter by cooling the drawn down filaments by passing them through a quenching zone and directing cooling gas over them to cool them therein, the low temperature of extrusion, the characteristics of said hot zone, and said drawing down in said hot zone interacting to substantially eliminate the occurrence of resonance in the filaments.
Claim 16
Dependent Claim
29 words
The method recited in claim 12, in which said polypropylene has a narrow molecular weight distribution, and said extrusion temperature is in the range 415° F. to 350° F.
Claim 17
Dependent Claim
18 words
The method recited in claim 13, in which said polypropylene has a swell value of less than 3.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-11-30 | 1985-06-01 | 1985-12-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-11-30 | 1989-06-01 | 1989-12-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-11-30 | 1993-06-01 | 1993-12-01 | $7700.00 | Window Closed / Lapsed |