US3677460A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Envelope having chemically treated edges
Assignee: Econo-Mail Inc
•
Filing: 1970-04-13
•
Granted: 1972-07-18
•
Expires: 1990-04-13
Abstract
Abstract The present process is for opening paper constructions of 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
- 👤 Nelson Whitman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 14:56
CPC Classifications
B; B43; B43M; B43M7/00; B43M7/004; B65; B65D; B65D27/00; B65D27/32; Y; Y10; Y10S; Y10S83/00; Y10S83/912
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
15 words
An envelope as claimed in claim 1 in which said agent comprises n-propyl sodium sulfate.
Claim 2
Dependent Claim
22 words
An envelope as claimed in claim 1 in which the n-propyl sodium sulfate is present along three coextensive edges of said envelope.
Claim 3
Dependent Claim
39 words
An envelope as claimed in claim 1 wherein said edge has a first coating of a lower molecular weight alkyl sodium sulfate and a second coating of a chemical developing agent, said plural coatings being superimposed on each other.
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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) | 1975-07-18 | 1976-01-17 | 1976-07-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-18 | 1980-01-17 | 1980-07-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-18 | 1984-01-17 | 1984-07-18 | $7700.00 | Window Closed / Lapsed |