Patent US3853661A successfully refreshed from Google Patents.
US3853661A
Expired / Lapsed
US
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A method of producing plastic bags
Assignee: Mitsubishi Chemical Corp
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Filing: 1972-04-24
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Granted: 1974-12-10
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Expires: 1992-04-24
Abstract
Abstract This invention relates to a method of producing plastic bags made of cylindrical film which is manufactured by the well known method called the ''''inflation method,'''' being improved and characterized in forming film in layers which are crossed in their stretched directions by using a compound die assembled with a plurality of annular dies concentrically.
Inventors
- 👤 M Sudo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 13:40
CPC Classifications
B; B29; B29C; B29C48/00; B29C48/03; B29C48/09; B29C48/10; B29C48/001; B29C48/0013; B29C48/0015; B29C48/16; B29C48/18; B29C48/21; B29C48/25; B29C48/30; B29C48/32; B29C48/33; B32; B32B; B32B27/00; B32B27/06; B32B27/08; B32B27/32; B32B38/00; B32B38/18; B32B38/1825; B32B38/1833; B29C48/0018; B29C48/0019; B32B2307/00; B32B2307/50; B32B2307/514; B32B2307/518; B32B2323/00; B32B2323/10; Y; Y10; Y10S; Y10S383/00; Y10S383/908
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
88 words
A method of forming plastic bags comprising the steps of extruding plastic material in molten condition through at least two concentric annular gaps formed in concentric cylindrical dies to form at least one pair of bubbles of plastic material in which one is located within the other; rotating during such extrusion at least one of said dies relative to the other; and blowing air only into said one bubble so that the whole outer surface thereof is in full contact with the inner surface of the other bubble.
Claim 2
Independent Claim
88 words
A method of forming plastic bags comprising the steps of extruding plastic material in molten condition through at least two concentric annular gaps formed in concentric cylindrical dies to form at least one pair of bubbles of plastic material in which one is located within the other; rotating during such extrusion at least one of said dies relative to the other; and blowing air only into said one bubble so that the whole outer surface thereof is in full contact with the inner surface of the other bubble.
Claim 3
Dependent Claim
17 words
A method as defined in claim 1, wherein both gaps are supplied with the same plastic material.
Claim 4
Dependent Claim
30 words
A method as defined in claim 1, wherein the plastice material supplied to one of the gaps is different from the plastic material supplied to the other of said gaps.
Claim 5
Dependent Claim
35 words
A method as defined in claim 1, wherein the inner of said concentric gaps is supplied with plastic material having a lower melting point than that supplied to the outer one of said annular gaps.
Claim 6
Dependent Claim
50 words
A method as defined in claim 4, and including the step of cooling the outer bubble while maintaining the inner bubble in plastic state during expansion and contacting thereof with said outer bubble, and flattening the bubbles by passing the same through the nip of a pair of rotating rolls.
Claim 7
Independent Claim
74 words
A method of forming plastic bags comprising the steps of extruding plastic material in molten condition through at least two concentric annular gaps formed in concentric cylindrical dies to form at least one pair of bubbles of plastic material of which one is located within the other; rotating during such extrusion both dies in opposite directions; and blowing air into said one bubble to expand said one bubble into contact with the other bubble.
Claim 8
Independent Claim
74 words
A method of forming plastic bags comprising the steps of extruding plastic material in molten condition through at least two concentric annular gaps formed in concentric cylindrical dies to form at least one pair of bubbles of plastic material of which one is located within the other; rotating during such extrusion both dies in opposite directions; and blowing air into said one bubble to expand said one bubble into contact with the other bubble.
Claim 9
Dependent Claim
19 words
A method as defined in claim 6, wherein both dies are rotated In opposite directions at the same speed.
Claim 10
Dependent Claim
18 words
A method as defined in claim 6, wherein both dies are rotated in opposite directions at different speeds.
Claim 11
Independent Claim
103 words
A method of forming plastic bags comprising the steps of extruding plastic material in molten condition through three concentric annular gaps formed in three concentric cylindrical dies to form three plastic bubbles of which a first one is located in a second one and the latter in the third of said three bubbles; rotating during such extrusion the outermost and the innermost of said dies in opposite directions while holding the intermediate die stationarily; and blowing air into said first of said bubbles to expand said first bubble into contact with said second bubbles and the latter into contact with said third bubble.
Claim 12
Independent Claim
103 words
A method of forming plastic bags comprising the steps of extruding plastic material in molten condition through three concentric annular gaps formed in three concentric cylindrical dies to form three plastic bubbles of which a first one is located in a second one and the latter in the third of said three bubbles; rotating during such extrusion the outermost and the innermost of said dies in opposite directions while holding the intermediate die stationarily; and blowing air into said first of said bubbles to expand said first bubble into contact with said second bubbles and the latter into contact with said third bubble.
Claim 13
Dependent Claim
38 words
A method as defined in claim 9, wherein the gap formed in said intermediate die is supplied with plastic material having a lower melting point than the plastic materials supplied to the gaps of the other two dies.
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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) | 1977-12-09 | 1978-06-10 | 1978-12-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-09 | 1982-06-10 | 1982-12-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-09 | 1986-06-10 | 1986-12-10 | $7700.00 | Window Closed / Lapsed |