US3871573A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process and agents for opening paper constructions
Assignee: Thor Dahl Inc
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Filing: 1972-06-16
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Granted: 1975-03-18
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Expires: 1992-06-16
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
- 👤 Nelson Whitman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 16:27
CPC Classifications
B; B65; B65D; B65D27/00; B65D27/32; B43; B43M; B43M7/00; B43M7/004
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
95 words
IN A PAPER ENVELOPE OF THE TYPE HAVING OPPOSED SHEETS FOLDED RELATIVE TO EACH OTHER AND CONNECTED TOGETHER AT A PLURALITY OF EDGES THE IMPROVEMENT OF WHICH COMPRISES AT LEAST A PORTION OF THE ENVELOPE ADJACENT AT LEAST ONE OF SAID EDGES BEING IMPREGNATED WITH A CHEMICAL SENSITIZING AGENT CONSISTING ESSENTIALLY OF A HIGHER MOLECULAR WEIGHT ALKYL SODIUM SULFATE, WHEREBY TREATMENT OF AT LEAST ONE OF SAID EDGES WITH A CHEMICAL DEVELOPING AGENT SUBJECTS THE PAPER OF SAID EDGE TO A CONTROLLED CHEMICAL DEGRADATION TO AFFECT THE SEPARATION OF THE OPPOSED SHEETS ALONG SAID EDGE.
Claim 2
Dependent Claim
95 words
IN A PAPER ENVELOPE OF THE TYPE HAVING OPPOSED SHEETS FOLDED RELATIVE TO EACH OTHER AND CONNECTED TOGETHER AT A PLURALITY OF EDGES THE IMPROVEMENT OF WHICH COMPRISES AT LEAST A PORTION OF THE ENVELOPE ADJACENT AT LEAST ONE OF SAID EDGES BEING IMPREGNATED WITH A CHEMICAL SENSITIZING AGENT CONSISTING ESSENTIALLY OF A HIGHER MOLECULAR WEIGHT ALKYL SODIUM SULFATE, WHEREBY TREATMENT OF AT LEAST ONE OF SAID EDGES WITH A CHEMICAL DEVELOPING AGENT SUBJECTS THE PAPER OF SAID EDGE TO A CONTROLLED CHEMICAL DEGRADATION TO AFFECT THE SEPARATION OF THE OPPOSED SHEETS ALONG SAID EDGE.
Claim 3
Dependent Claim
19 words
A paper envelope as claimed in claim 1 in which said sensitizing agent is impregnated along three coextensive edges.
Claim 4
Dependent Claim
37 words
A paper envelope as claimed in claim 1 wherein said edge has a first coating of said chemical sensitizing agent and a second coating of a chemical developing agent, said plural coatings being superimposed on each other.
Claim 5
Dependent Claim
16 words
A paper envelope as claimed in claim 1 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) | 1978-03-17 | 1978-09-16 | 1979-03-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-17 | 1982-09-16 | 1983-03-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-17 | 1986-09-16 | 1987-03-18 | $7700.00 | Window Closed / Lapsed |