Patent US3756758A successfully refreshed from Google Patents.
US3756758A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Extrusion die for plastic film
Assignee: Chemplex Co
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Filing: 1969-07-15
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Granted: 1973-09-04
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Expires: 1989-07-15
Abstract
Abstract An extrusion apparatus for producing plastic film and especially blown film that comprises a die having a passage through it with an entrance and an annular exit from which the plastic film flows in tubular form together with a divider in the passage for dividing the plastic material during its flow into a plurality of spaced separated streams and subdividing each stream into a further plurality of side-by-side film segments, means for then joining the segments at their edges in tubular form, and merging means within the die for merging the tubes of each stream in concentric interfacial contact, with the result that the tubular structure emerging from the annular exit has a wall formed of a plurality of facially merged plastic layers. For improved strength and appearance, each edge joined area of one layer is covered by a film segment of the next tubular layer.
Inventors
- 👤 G Prall
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 15:01
CPC Classifications
B; B29; B29C; B29C48/00; B29C48/25; B29C48/30; B29C48/32; B29C48/335; B29C48/336; B29C48/3363; B29C48/03; B29C48/09; B29C48/10; B29C48/14; B29C48/147; B29C48/1472; B29C48/16; B29C48/18; B29C48/19; B29C48/21; B29C2791/00; B29C2791/004; B29C2791/007
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
160 words
Extrusion apparatus for producing plastic film, comprising: a die having a passage means therethrough with an entrance and an annular exit for flowable plastic material; dividing means in said passage means for dividing said material into a plurality of spaced separated streams; a plurality of film forming means for arranging said streams in separate films; and merging means for merging said films in interfacial merged tubular form prior to reaching said exit, said die having a central axis with which said passage entrance and annular exit are concentric, with said plurality of streams spaced along said axis, each said film forming means comprising a plurality of adjacent passages radiating from said axis, and with each said passage having a straight portion of substantially uniform width adjacent said axis and an outwardly flared portion at said annular exit, said flared portions for each said film forming means being coplanar in a plane that is at substantially right angles to said axis.
Claim 2
Dependent Claim
160 words
Extrusion apparatus for producing plastic film, comprising: a die having a passage means therethrough with an entrance and an annular exit for flowable plastic material; dividing means in said passage means for dividing said material into a plurality of spaced separated streams; a plurality of film forming means for arranging said streams in separate films; and merging means for merging said films in interfacial merged tubular form prior to reaching said exit, said die having a central axis with which said passage entrance and annular exit are concentric, with said plurality of streams spaced along said axis, each said film forming means comprising a plurality of adjacent passages radiating from said axis, and with each said passage having a straight portion of substantially uniform width adjacent said axis and an outwardly flared portion at said annular exit, said flared portions for each said film forming means being coplanar in a plane that is at substantially right angles to said axis.
Claim 3
Dependent Claim
196 words
Extrusion apparatus for producing plastic film, comprising: a die having a central axis and a passage means through the die with an entrance and an annular exit for flowable plastic material, the entrance and exit being concentric to each other and to said axis; dividing means in said passage means for dividing said material into a plurality of separated streams spaced along said axis; separate film forming means for arranging said streams in separate films with each film forming means comprising means providing a plurality of adjacent passages radiating from said axis in which each said passage has a straight portion of substantially uniform width adjacent said axis and an outwardly flared portion at said annular exit, said flared portions for each film forming means being coplanar in a plane that is at substantially right angles to said axis and being in an adjacent series with their outer edges merged in intermingling areas at said annular exit, the intermingling areas of one said stream dividing means being angularly offset from the intermingling areas of the next stream dividing means; and merging means for merging said films in interfacial merged tubular form prior to reaching said exit.
Claim 4
Dependent Claim
196 words
Extrusion apparatus for producing plastic film, comprising: a die having a central axis and a passage means through the die with an entrance and an annular exit for flowable plastic material, the entrance and exit being concentric to each other and to said axis; dividing means in said passage means for dividing said material into a plurality of separated streams spaced along said axis; separate film forming means for arranging said streams in separate films with each film forming means comprising means providing a plurality of adjacent passages radiating from said axis in which each said passage has a straight portion of substantially uniform width adjacent said axis and an outwardly flared portion at said annular exit, said flared portions for each film forming means being coplanar in a plane that is at substantially right angles to said axis and being in an adjacent series with their outer edges merged in intermingling areas at said annular exit, the intermingling areas of one said stream dividing means being angularly offset from the intermingling areas of the next stream dividing means; and merging means for merging said films in interfacial merged tubular form prior to reaching said exit.
Claim 5
Dependent Claim
243 words
Extrusion apparatus for producing plastic film, comprising: a die having a passage means therethrough with an entrance and an annular exit for flowable plastic material, dividing means in said passage means for dividing said material into a plurality of spaced separated streams; film forming means for atranging said streams in separate films with each film foRming means comprising a plurality of adjacent passages extending from said entrance toward said annular exit, said dividing means comprising a spreader plate in said die having opposite side surfaces each provided with a plurality of said film forming passages, said die comprising separable parts cooperating to form a chamber means in which said spreader plate is located with an outer wall of said chamber and the outer edge of said plate being located at said annular exit, said die having a central axis and said passages on each side of said plate radiating outwardly from said axis, each said passage having a narrow portion adjacent said entrance and an outwardly flared portion from the narrow portion to said annular exit, the outer extremities of said flared portions merging at said annular exit, said flared portions being in an adjacent series with their outer edges in intermingling areas at said annular exit with said areas of one said stream dividing means angularly offset from those of the next stream dividing means; and merging means for merging said films in interfacial merged tubular form prior to reaching said exit.
Claim 6
Dependent Claim
243 words
Extrusion apparatus for producing plastic film, comprising: a die having a passage means therethrough with an entrance and an annular exit for flowable plastic material, dividing means in said passage means for dividing said material into a plurality of spaced separated streams; film forming means for atranging said streams in separate films with each film foRming means comprising a plurality of adjacent passages extending from said entrance toward said annular exit, said dividing means comprising a spreader plate in said die having opposite side surfaces each provided with a plurality of said film forming passages, said die comprising separable parts cooperating to form a chamber means in which said spreader plate is located with an outer wall of said chamber and the outer edge of said plate being located at said annular exit, said die having a central axis and said passages on each side of said plate radiating outwardly from said axis, each said passage having a narrow portion adjacent said entrance and an outwardly flared portion from the narrow portion to said annular exit, the outer extremities of said flared portions merging at said annular exit, said flared portions being in an adjacent series with their outer edges in intermingling areas at said annular exit with said areas of one said stream dividing means angularly offset from those of the next stream dividing means; and merging means for merging said films in interfacial merged tubular form prior to reaching said exit.
Claim 7
Dependent Claim
26 words
The apparatus of claim 1 wherein said flared portions are in an adjacent series with their outer edges merged in intermingling areas at said annular exit.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-09-03 | 1977-03-05 | 1977-09-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-03 | 1981-03-05 | 1981-09-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-03 | 1985-03-05 | 1985-09-04 | $7700.00 | Window Closed / Lapsed |