Patent US3816213A successfully refreshed from Google Patents.
US3816213A
Expired / Lapsed
US
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Process and agents for opening paper constructions
Assignee: THOR DAHL INC US
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Filing: 1971-10-26
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Granted: 1974-06-11
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Expires: 1991-10-26
Abstract
Abstract The present process is for opening paper constructions or structures, such as the marginal edges of envelopes, by treating a portion with a sensitizing agent which comprises an alkyl sodium sulfate, thereafter applying a developing agent comprising a strong organic acid to the sensitized portion, heating the developed portion to degrade it and thereafter applying mild mechanical action to remove the degraded portion.
Inventors
- 👤 N Whitman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 16:43
CPC Classifications
B; B43; B43M; B43M7/00; B43M7/004; B65; B65D; B65D27/00; B65D27/32; Y; Y10; Y10T; Y10T156/00; Y10T156/11; Y10T156/1111; Y10T156/1116
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
20 words
A process as claimed in claim 1 in which said sensitizing agent comprises a lower molecular weight alkyl sodium sulfate.
Claim 2
Dependent Claim
16 words
A process as claimed in claim 1, in which said sensitizing agent comprises n-propyl sodium sulfate.
Claim 3
Dependent Claim
22 words
A process as claimed in claim 1 in which said sensitizing agent comprises about a 10 percent solution of n-propyl sodium sulfate.
Claim 4
Dependent Claim
18 words
A process as claimed in claim 4 in which said solution comprises a major amount of isopropyl alcohol.
Claim 5
Dependent Claim
15 words
A process as claimed in claim 1 in which said developing compound comprises oxalic acid.
Claim 6
Dependent Claim
20 words
A process as claimed in claim 1 in which said developing compound comprises a 10 percent solution of oxalic acid.
Claim 7
Dependent Claim
19 words
A process as claimed in claim 1 wherein said sensitizing agent comprises a higher molecular weight alkyl sodium sulfate.
Claim 8
Dependent Claim
15 words
A process as claimed in claim 1 wherein said sensitizing agent is sodium lauryl sulfate.
Claim 9
Dependent Claim
15 words
A process as claimed in claim 1 in which said developing agent is acetic acid.
Claim 10
Dependent Claim
20 words
A process as claimed in claim 1 in which said predetermined portion is a zone along a plurality of edges.
Claim 11
Dependent Claim
112 words
A process for opening a portion of a paper envelope, to which a chemical sensitizing agent comprising an alkyl sodium sulfate has been applied to a predetermined portion adjacent at least one edge of said envelope, said process consisting of steps of: (1) applying a chemical developing agent comprising an organic acid selected from the class consisting of oxalic acid and acetic acid to said predetermined portion to release a degrading agent from the developed sensitizing agent to degrade said predetermined portion, said degrading agent comprising sulfuric acid of sufficient concentration to degrade the paper, (2) heating the developed sensitized portion, and (3) applying mild mechanical action to the developed sensitized portion.
Claim 12
Dependent Claim
20 words
A process as claimed iN claim 12 in which said sensitizing agent comprises a lower molecular weight alkyl sodium sulfate.
Claim 13
Dependent Claim
16 words
A process as claimed in claim 12 in which said sensitizing agent comprises n-propyl sodium sulfate.
Claim 14
Dependent Claim
22 words
A process as claimed in claim 12 in which said sensitizing agent comprises about a 10 percent solution of n-propyl sodium sulfate.
Claim 15
Dependent Claim
18 words
A process as claimed in claim 15 in which said solution comprises a major amount of isopropyl alcohol.
Claim 16
Dependent Claim
15 words
A process as claimed in claim 12 in which said developing compound comprises oxalic acid.
Claim 17
Dependent Claim
20 words
A process as claimed in claim 12 in which said developing compound comprises a 10 percent solution of oxalic acid.
Claim 18
Dependent Claim
15 words
A process as claimed in claim 12 in which said developing agent is acetic acid.
Claim 19
Dependent Claim
20 words
A process as claimed in claim 12 in which said predetermined portion is a zone along a plurality of edges.
Claim 20
Dependent Claim
19 words
A process as claimed in claim 12 wherein said sensitizing agent comprises a higher molecular weight alkyl sodium sulfate.
Claim 21
Dependent Claim
15 words
A process as claimed in claim 12 wherein said sensitizing agent is sodium lauryl sulfate.
References Cited (Backward Citations)
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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) | 1977-06-10 | 1977-12-10 | 1978-06-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-10 | 1981-12-10 | 1982-06-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-10 | 1985-12-10 | 1986-06-11 | $7700.00 | Window Closed / Lapsed |