US4330501A
Expired / Lapsed
US
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Method and apparatus for cooling film bubble of low strain hardening polymers
Assignee: Union Carbide Corp
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Filing: 1980-06-30
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Granted: 1982-05-18
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Expires: 2000-06-30
Abstract
Abstract A process and apparatus are disclosed for forming blown film of a low strain hardening polymer, such as a low pressure polymerized-low density ethylene copolymer, including an improved film bubble cooling technique which permits high production rates to be achieved with good film bubble stability. The disclosed process comprises cooling a molten film bubble by contacting the outside of the film bubble with separate annular streams of cooling fluid fed through at least two stacked annular cooling rings disposed around the film bubble, wherein all or substantially all of the cooling fluid exits the system through a common plane formed by the last cooling ring. The disclosed apparatus comprises means for forming a molten film bubble and means for cooling same including at least two separate annular cooling rings disposed around the bubble, each provided with means for feeding an annular cooling fluid stream against the bubble and further including means whereby all or substantially all of said cooling fluid exits the system through a common plane formed by the last cooling ring.
Inventors
- 👤 David N. Jones
- 👤 Stuart J. Kurtz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 09:49
CPC Classifications
B; B29; B29C; B29C48/00; B29C48/25; B29C48/88; B29C48/885; B29C48/03; B29C48/09; B29C48/10; B29C48/911; B29C48/9115; B29C48/912
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
95 words
A process for cooling a molten tube of a low strain hardening polymer, while maintaining the stability of said molten tube, which comprises contacting the outside periphery of said molten tube with at least two annular streams of cooling fluid from at least two annular cooling rings disposed around said molten tube and through which said tube advances, wherein substantially all of the cooling fluid flows parallel to and in the same direction as said tube and exits the system through a common plane formed by the last cooling ring through which said tube advances.
Claim 2
Dependent Claim
95 words
A process for cooling a molten tube of a low strain hardening polymer, while maintaining the stability of said molten tube, which comprises contacting the outside periphery of said molten tube with at least two annular streams of cooling fluid from at least two annular cooling rings disposed around said molten tube and through which said tube advances, wherein substantially all of the cooling fluid flows parallel to and in the same direction as said tube and exits the system through a common plane formed by the last cooling ring through which said tube advances.
Claim 3
Dependent Claim
61 words
A process according to claim 1, wherein the extensional viscosity index of said polymer is no greater than about 4.5, said index comprising the ratio of the extensional viscosity of said polymer at a total Hencky strain of 2 to its extensional viscosity at a total Hencky strain of 0.2, both calculated at a strain rate of 1 second -1 .
Claim 4
Dependent Claim
30 words
A process according to claim 1, wherein said polymer is a low pressure polymerized-low density copolymer of ethylene and at least one C 3 to a C 8 alpha-olefin hydrocarbon.
Claim 5
Dependent Claim
34 words
A process according to claim 3, wherein said polymer is a copolymer of at least 90 mole percent ethylene and less than 10 mole percent of said C 3 to C 8 alpha-olefin hydrocarbon.
Claim 6
Dependent Claim
49 words
A process according to claim 1, wherein said advancing molten tube is a film bubble formed by tubular blown extrusion and is cooled by two annular streams of cooling fluid from upper and lower annular cooling rings, and said upper cooling ring is downstream of said lower cooling ring.
Claim 7
Dependent Claim
33 words
A process according to claim 5, wherein the amount and velocity of cooling fluid from said lower cooling ring is sufficient to cool said film bubble by about 75° to about 100° F.
Claim 8
Dependent Claim
29 words
A process according to claim 5, wherein said upper cooling ring is disposed downstream of said lower cooling ring by a distance of from about 4 to 15 inches.
Claim 9
Dependent Claim
30 words
A process according to claim 7, wherein the space between said upper and lower cooling rings is sealed to prevent said cooling fluid from exiting the system from said space.
Claim 10
Dependent Claim
17 words
A process according to claim 5, wherein said lower cooling ring comprises a dual lip air ring.
Claim 11
Dependent Claim
18 words
A process according to claim 9, where said air ring is recessed into the face of said die.
Claim 12
Dependent Claim
43 words
A process according to claim 9, wherein said air ring is disposed around said molten film bubble at a distance above the face of said die to define a space through which a portion of said cooling fluid is vented from the system.
Claim 13
Dependent Claim
44 words
A process according to claim 10, wherein said air ring is disposed around said molten film bubble at a distance above the face of said die recess to define a space through which a portion of said cooling fluid is vented from the system.
Claim 14
Dependent Claim
17 words
A process according to claim 5, wherein said upper cooling ring comprises a single orifice air ring.
Claim 15
Dependent Claim
23 words
A process according to claim 13, wherein the upper lip height of said upper air ring is no more than about 4 inches.
Claim 16
Dependent Claim
18 words
A process according to claim 1, wherein the lip of said die gap is greater than 50 mils.
Claim 17
Dependent Claim
27 words
A process according to claim 3, wherein said polymer contains up to 10 weight percent, based on the total polymer weight, of a high pressure-low density polyethylene.
Claim 18
Dependent Claim
146 words
Apparatus for producing a film tube from a low strain hardening polymer comprising: means including a die for extruding a molten tube of said polymer; and means for cooling said molten polymer tube whereby a frost line is formed while maintaining the stability of said molten polymer tube, including at least 2 annular cooling rings disposed around said molten polymer tube upstream of said frost line, each of said cooling rings being provided with means for forcing an annular stream of cooling fluid into contact with the outside periphery of said molten polymer tube, said cooling means further including means for venting said cooling fluid from said apparatus whereby substantially all of said cooling fluid flows parallel to and in the same direction as said tube and exits said apparatus through a common plane formed by the last cooling ring through which said polymer tube advances.
Claim 19
Dependent Claim
146 words
Apparatus for producing a film tube from a low strain hardening polymer comprising: means including a die for extruding a molten tube of said polymer; and means for cooling said molten polymer tube whereby a frost line is formed while maintaining the stability of said molten polymer tube, including at least 2 annular cooling rings disposed around said molten polymer tube upstream of said frost line, each of said cooling rings being provided with means for forcing an annular stream of cooling fluid into contact with the outside periphery of said molten polymer tube, said cooling means further including means for venting said cooling fluid from said apparatus whereby substantially all of said cooling fluid flows parallel to and in the same direction as said tube and exits said apparatus through a common plane formed by the last cooling ring through which said polymer tube advances.
Claim 20
Dependent Claim
40 words
An apparatus according to claim 17, wherein said cooling rings include upper and lower cooling rings, said lower cooling ring is disposed adjacent the face of said die and said upper cooling ring is downstream of said lower cooling ring.
Claim 21
Dependent Claim
17 words
An apparatus according to claim 18, wherein said lower cooling ring comprises a dual lip air ring.
Claim 22
Dependent Claim
18 words
An apparatus according to claim 19, wherein said air ring is recessed into the face of said die.
Claim 23
Dependent Claim
43 words
An apparatus according to claim 19, wherein said air ring is disposed around said molten polymer tube at a distance above the face of said die to define a space through which a portion of said cooling fluid is vented from the system.
Claim 24
Dependent Claim
44 words
An apparatus according to claim 20, wherein said air ring is disposed around said molten polymer tube at a distance above the face of said die recess to define a space through which a portion of said cooling fluid is vented from the system.
Claim 25
Dependent Claim
17 words
An apparatus according to claim 18, wherein said upper cooling ring comprises a single orifice air ring.
Claim 26
Dependent Claim
24 words
An apparatus according to claim 23, wherein the height of the upper lip of said orifice air ring is no more than 4 inches.
Claim 27
Dependent Claim
18 words
An apparatus according to claim 17, wherein the lip gap of said die is greater than 50 mils.
Claim 28
Dependent Claim
29 words
An apparatus according to claim 18, wherein said upper cooling ring is disposed downstream of said lower cooling ring by a distance of from about 4 to 15 inches.
Claim 29
Dependent Claim
30 words
An apparatus according to claim 26, wherein the space between said upper and lower cooling rings is sealed to prevent said cooling fluid from exiting the system from said space.
References Cited (Backward Citations)
US3167814A
Cited
US3307218A
Cited
US3548042A
Cited
US3568252A
Cited
GB1120075A
Cited
US3819790A
Cited
US3888609A
Cited
DE2259732A1
Cited
US3867083A
Cited
US3976732A
Cited
US4139338A
Cited
US4115048A
Cited
US4145177A
Cited
US4243619A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-05-17 | 1985-11-16 | 1986-05-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-05-17 | 1989-11-16 | 1990-05-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-05-17 | 1993-11-16 | 1994-05-18 | $7700.00 | Window Closed / Lapsed |