US3790744A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of forming a line of weakness in a multilayer laminate
Assignee: Rexam Beverage Can Co
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Filing: 1971-07-19
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Granted: 1974-02-05
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Expires: 1991-07-19
Abstract
Abstract A method of forming a line of weakness in at least one but not all layers of multilayer laminate which comprises effecting relative movement between a beam of radiant energy of a particular predetermined wavelength and intensity and the laminate so that the energy is selectively relatively absorbed by at least one layer in an amount and manner that alters the structure of the layer and thereby forms a line of weakness in the laminate. The source of radiant energy preferably is a laser. The laminate layers can be comprised of any material used in manufacturing multilayer packaging laminates such as thermoplastics, thermosets, paper and foil. Preferably, the laminate includes at least one layer of thermoplastic material. The layer that absorbs more energy can be an adhesive.
Inventors
- 👤 W Bowen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 20:47
CPC Classifications
B; B29; B29C; B29C59/00; B29C59/007; B23; B23K; B23K26/00; B23K26/0006; B23K26/352; B23K26/359; B23K26/36; B23K26/361; B23K26/40; B23K2103/00; B23K2103/16; B23K2103/166; B23K2103/172; B23K2103/30; B23K2103/40; B23K2103/42; B29C35/00; B29C35/02; B29C35/08; B29C35/0805; B29C2035/0838; B29C2791/00; B29C2791/004; B29C2791/009; B29C37/00; B29C37/0053; B29C37/0057; B29L; B29L2009/00; Y; Y10; Y10T; Y10T156/00; Y10T156/10; Y10T156/1052; Y10T225/00; Y10T225/30; Y10T225/304; Y10T83/00; Y10T83/02; Y10T83/0333
Claims Analysis
Total Claims: 31
Claim 1
Independent Claim
155 words
A method of forming at least one line of weakness in a laminate having multiple layers, said line of weakness being formed in at least one but not all of said layers, which comprises, effecting at a certain rate of speed along a predetermined path, relative movement between said laminate and at least one theretoward source-directed beam of radiant energy, said beam being directed to pass through a layer proximate to the source without vaporizing said proximate layer, said energy having a particular predetermined wavelength and intensity such that said energy is selectively relatively absorbed by said at least one layer in an amount sufficient to directly preferentially vaporize said at least one layer and gases formed by said vaporization form said line of weakness in said at least one layer and in said laminate, said at least one layer being a layer which is not the most proximate layer in relation to said source.
Claim 2
Independent Claim
155 words
A method of forming at least one line of weakness in a laminate having multiple layers, said line of weakness being formed in at least one but not all of said layers, which comprises, effecting at a certain rate of speed along a predetermined path, relative movement between said laminate and at least one theretoward source-directed beam of radiant energy, said beam being directed to pass through a layer proximate to the source without vaporizing said proximate layer, said energy having a particular predetermined wavelength and intensity such that said energy is selectively relatively absorbed by said at least one layer in an amount sufficient to directly preferentially vaporize said at least one layer and gases formed by said vaporization form said line of weakness in said at least one layer and in said laminate, said at least one layer being a layer which is not the most proximate layer in relation to said source.
Claim 3
Dependent Claim
13 words
The method of claim 1 wherein said laminate is at least partly flexible.
Claim 4
Dependent Claim
13 words
The method of claim 1 wherein said at least one layer is polymeric.
Claim 5
Dependent Claim
46 words
The method of claim 3 wherein one or more of the non-proximate layers other than said at least one layer is foil and reflects an amount of said energy sufficient to aid in the forming of said line of weakness in said at least one layer.
Claim 6
Dependent Claim
14 words
The method of claim 1 wherein said at least one layer is a thermoset.
Claim 7
Dependent Claim
46 words
The method of claim 5 wherein one or more of the non-proximate layers other than said at least one layer is foil and reflects an amount of said energy sufficient to aid in the forming of said line of weakness in said at least one layer.
Claim 8
Dependent Claim
13 words
The method of claim 1 wherein said at least one layer is paper.
Claim 9
Dependent Claim
46 words
The method of claim 7 wherein one or more of the non-proximate layers other than said at least one layer is foil and reflects an amount of said energy sufficient to aid in the forming of said line of weakness in said at least one layer.
Claim 10
Dependent Claim
13 words
The method of claim 1 wherein said at least one layer is thermoplastic.
Claim 11
Dependent Claim
46 words
The method of claim 9 wherein one or more of the non-proximate layers other than said at least one layer is foil and reflects an amount of said energy sufficient to aid in the forming of said line of weakness in said at least one layer.
Claim 12
Dependent Claim
15 words
The method of claim 1 wherein each of said layers of said laminate is polymeric.
Claim 13
Dependent Claim
15 words
The method of claim 1 wherein each of said layers of said laminate is thermoplastiC.
Claim 14
Dependent Claim
44 words
The method of claim 1 wherein one or more of the non-proximate layers other than said at least one layer reflects an amount of said energy sufficient to aid in the forming of said line of weakness in said at least one non-proximate layer.
Claim 15
Dependent Claim
15 words
The methd of claim 13 wherein said one or more non-proximate reflecting layers is foil.
Claim 16
Dependent Claim
48 words
The method of claim 1 wherein one or more of said multiple layers is oriented in a predetermined direction, and said orientation aids in the forming of said line of weakness such that greater processing speed is achieved than if said one or more layers was not oriented.
Claim 17
Dependent Claim
30 words
The method of claim 1 wherein said at least one layer is treated in a manner that makes it more absorptive of said energy than the rest of said layers.
Claim 18
Dependent Claim
14 words
The method of claim 1 wherein said at least one layer is an adhesive.
Claim 19
Dependent Claim
24 words
The method of claim 1 wherein said at least one layer has the highest coefficient of absorption of said multiple layers of said laminate.
Claim 20
Dependent Claim
28 words
The method of claim 1 wherein a layer other than said at least one layer has the highest coefficient of absorption of said multiple layers of said laminate.
Claim 21
Dependent Claim
56 words
The method of claim 19 wherein said other layer absorbs sufficient energy to vaporize some of its own material and thereby at least partly form said line of weakness in itself, and, gases resulting from said vaporization aid in the forming of said line of weakness in said at least one layer and in said laminate.
Claim 22
Dependent Claim
17 words
The method of claim 20 wherein said highest coefficient layer is adjacent said at least one layer.
Claim 23
Dependent Claim
13 words
The method of claim 21 wherein said highest coefficient layer is an adhesive.
Claim 24
Dependent Claim
33 words
The method of claim 1 wherein said at least one layer is formed of two substantially equally absorptive layers which selectively relatively absorb more of said energy than other layers of said laminate.
Claim 25
Dependent Claim
33 words
The method of claim 23 wherein one of said substantially equally absorptive layers degrades more readily than the other and said line of weakness is first formed in said more readily degradable layer.
Claim 26
Dependent Claim
39 words
The method of claim 23 one of said substantially equally absorptive layers is more oriented than the other, and a line of weakness is first formed in it rather than in the other of said substantially equally absorptive layers.
Claim 27
Dependent Claim
20 words
The method of claim 25 wherein said direction of orientation is substantially at right angles to said line of weakness.
Claim 28
Dependent Claim
74 words
The method of claim 1 wherein the laminate is in the form of a package having a seal, and said one or more lines of weakness are formed adjacent said seal so that said one or more lines of weakness cooperate with said seal such that one or more sealed layers of said package can be released from adjacent layers of said package in a manner that said package is opened along said seal.
Claim 29
Dependent Claim
60 words
The method of claim 1 wherein one or more of said multiple layers is oriented in a predetermined direction thereby imparting a partial preferential weakness in said laminate that cooperates with said formed line of weakness to achieve easier manipulation of said laminate along said line of weakness than if said one or more multiple layers was not so oriented.
Claim 30
Dependent Claim
21 words
The method of claim 28 wherein said direction of orientation is substantially in the same direction as said line of weakness.
Claim 31
Dependent Claim
20 words
The method of claim 1 wherein said source-directed beam is interrupted so that said line of weakness is not continuous.
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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) | 1977-02-04 | 1977-08-06 | 1978-02-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-04 | 1981-08-06 | 1982-02-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-04 | 1985-08-06 | 1986-02-05 | $7700.00 | Window Closed / Lapsed |