US4357291A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Double metering extruder screw and method of extrusion
Assignee: Union Carbide Corp
•
Filing: 1980-08-28
•
Granted: 1982-11-02
•
Expires: 2000-08-28
Abstract
Abstract A high output extruder screw which produces throughputs at lower temperatures and lower specific energy input. The screw has a feed section, a first short transition section, a first metering section, a second short transition section and a second metering section wherein the screw diameter increases from the feed section to the second metering section. There is also provided a method for extruding specific ethylene polymers.
Inventors
- 👤 John C. Miller
- 👤 Archibald L. Burnett
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 18:12
CPC Classifications
B; B29; B29C; B29C48/00; B29C48/022; B29C48/03; B29K; B29K2023/00
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
160 words
An extruder screw for extruding low density narrow molecular weight distribution linear ethylene polymers which comprises: a screw root and a helical feed flight of constant pitch; a feed section wherein said screw root diameter is constant; a first short transition section having at least about one-half turn of said helical feed flight and wherein said screw root has an increasing diameter and is larger than the diameter in said feed section; a first metering section wherein said screw root has a constant screw root diameter greater than the screw root diameter in said feed and first short transition sections; a second short transition section having at least about one-half turn of said helical flight and wherein said screw root diameter is larger than the diameter of the screw root in said first metering section; and a second metering section wherein said screw has a constant screw root diameter greater than the screw root diameter in said first metering section.
Claim 2
Dependent Claim
160 words
An extruder screw for extruding low density narrow molecular weight distribution linear ethylene polymers which comprises: a screw root and a helical feed flight of constant pitch; a feed section wherein said screw root diameter is constant; a first short transition section having at least about one-half turn of said helical feed flight and wherein said screw root has an increasing diameter and is larger than the diameter in said feed section; a first metering section wherein said screw root has a constant screw root diameter greater than the screw root diameter in said feed and first short transition sections; a second short transition section having at least about one-half turn of said helical flight and wherein said screw root diameter is larger than the diameter of the screw root in said first metering section; and a second metering section wherein said screw has a constant screw root diameter greater than the screw root diameter in said first metering section.
Claim 3
Dependent Claim
18 words
An extruder screw according to claim 1 further including a mixing section associated with said second metering section.
Claim 4
Dependent Claim
22 words
An extruder screw according to claim 1 wherein said feed section has a length of about 6.5 times the nominal screw diameter.
Claim 5
Dependent Claim
25 words
An extruder screw according to claims 1 or 3 wherein said first metering section has a length of about 6 times the nominal screw diameter.
Claim 6
Dependent Claim
23 words
An extruder screw according to claim 4 wherein said second metering section has a length of about 3-4 times the nominal screw diameter.
Claim 7
Independent Claim
141 words
A method for extruding low density narrow molecular weight distribution, linear, ethylene polymers which comprises introducing said granular polymers into an extruder apparatus having an extruder screw having a helical feed flight of constant pitch and including a feed zone comprising a constant screw root diameter; thence passing said polymers through a first short transition zone of said screw wherein the screw root diameter increases; thence passing said polymers through a first metering zone of said screw having a constant screw root diameter greater than the screw root diameter in said feed zone; continuing passage of said polymer into and through a second short transition zone wherein the screw root diameter increases; and thence passing said polymer into and through a second metering zone having a constant screw root diameter greater than the screw root diameter in said first metering zone.
Claim 8
Independent Claim
141 words
A method for extruding low density narrow molecular weight distribution, linear, ethylene polymers which comprises introducing said granular polymers into an extruder apparatus having an extruder screw having a helical feed flight of constant pitch and including a feed zone comprising a constant screw root diameter; thence passing said polymers through a first short transition zone of said screw wherein the screw root diameter increases; thence passing said polymers through a first metering zone of said screw having a constant screw root diameter greater than the screw root diameter in said feed zone; continuing passage of said polymer into and through a second short transition zone wherein the screw root diameter increases; and thence passing said polymer into and through a second metering zone having a constant screw root diameter greater than the screw root diameter in said first metering zone.
Claim 9
Dependent Claim
26 words
A method according to claim 6 wherein said polymer leaving said second metering zone is introduced into a mixing zone associated with said second metering zone.
Claim 10
Dependent Claim
36 words
A method according to claim 7 in which said polymer is a copolymer of ethylene and at least one C 3 to C 8 alpha olefin having a melt index of about ≧0.1 to about ≦20.
Claim 11
Dependent Claim
33 words
A method according to claim 8 in which said polymer is a copolymer of ≧90 mol percent ethylene and ≦10 mol percent of at least one C 3 to C 8 alpha olefin.
Claim 12
Dependent Claim
33 words
A method according to claim 9 in which said copolymer has a molecular weight distribution of about ≧2.7 to ≦6.0 and a total unsaturation content of about ≧0.1 to ≦0.3 C=C/1000 C atoms.
Claim 13
Dependent Claim
33 words
A method according to claim 9 in which said copolymer has a melt flow ratio of about ≧22 to ≦40 and a total unsaturation content of about ≧0.1 to ≦0.3 C=C/1000 C atoms.
References Cited (Backward Citations)
US2702410A
Cited
US3300810A
Cited
US3496603A
Cited
US3767754A
Cited
US3712776A
Cited
US3862265A
Cited
US3905588A
Cited
US4129386A
Cited
US4267146A
Cited
US4282177A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-11-01 | 1986-05-03 | 1986-11-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-11-01 | 1990-05-03 | 1990-11-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-11-01 | 1994-05-03 | 1994-11-02 | $7700.00 | Window Closed / Lapsed |