US3884697A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Photographic process utilizing spiropyran compound dispersed in nitrocellulose films with high nitrogen content
Assignee: Individual
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Filing: 1974-03-19
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Granted: 1975-05-20
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Expires: 1994-03-19
Abstract
Abstract This invention relates to reverse photochromic nitrocellulose films which are produced by combining specific spiro-pyran compounds with specific types of nitrocellulose. Also, this invention relates to a method for producing the reverse photochromic nitrocellulose films. These reverse photochromic films are colored at room temperature and the coloring of the films can be erased by irradiation with visible light. The films can be restored to their original color when they are placed in the dark or when they are subjected to the irradiation with ultraviolet light. The novel films have superior color stability in the coloration-decoloration cycle.
Inventors
- 👤 Eiichi Inoue
- 👤 Mitsunobu Nakazawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 14:12
CPC Classifications
G; G03; G03C; G03C1/00; G03C1/685; Y; Y10; Y10S; Y10S430/00; Y10S430/163
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
120 words
A METHOD FOR PRODUCING A REVERSIBLE COLOR CHANGE IMAGE BY THE USE OF A REVERSE PHOTOCHROMIC FILM CONSISTING ESSENTIALLY OF NITROCELLULOSE HAVING A NITROGEN CONTENT OF FROM ABOUT 10 TO 12.2% BY WEIGHT AND A MOLECULAR WEIGHT OF ABOUT 10,000 TO 250,000 AND A SPIRO-PYAN COMPOUND BEING PRESENT IN AN AMOUNT OF ABOUT 1 PART BY WEIGHT PER 60 PARTS BY WEIGHT NITROCELLULOSE, SAID METHOD COMPRISING (I) DECOLORING SAID REVERSE PHOTOCHROMIC FILM, WHICH IS ORIGINALLY COLORED AND IN A STABLE STATE, BY SUBJECTING IT TO IRRADIATION WITH VISIBLE LIGHT TO FORM AN IMAGE, AND (II) RESTORING THE DECOLORED IMAGE TO THE ORIGINAL COLOR BY SUBJECTING THE FILM TO IRRADITION WITH ULTRAVIOLET LIGHT OR BY PLACING THE FILM IN THE DARK.
Claim 2
Independent Claim
120 words
A METHOD FOR PRODUCING A REVERSIBLE COLOR CHANGE IMAGE BY THE USE OF A REVERSE PHOTOCHROMIC FILM CONSISTING ESSENTIALLY OF NITROCELLULOSE HAVING A NITROGEN CONTENT OF FROM ABOUT 10 TO 12.2% BY WEIGHT AND A MOLECULAR WEIGHT OF ABOUT 10,000 TO 250,000 AND A SPIRO-PYAN COMPOUND BEING PRESENT IN AN AMOUNT OF ABOUT 1 PART BY WEIGHT PER 60 PARTS BY WEIGHT NITROCELLULOSE, SAID METHOD COMPRISING (I) DECOLORING SAID REVERSE PHOTOCHROMIC FILM, WHICH IS ORIGINALLY COLORED AND IN A STABLE STATE, BY SUBJECTING IT TO IRRADIATION WITH VISIBLE LIGHT TO FORM AN IMAGE, AND (II) RESTORING THE DECOLORED IMAGE TO THE ORIGINAL COLOR BY SUBJECTING THE FILM TO IRRADITION WITH ULTRAVIOLET LIGHT OR BY PLACING THE FILM IN THE DARK.
Claim 3
Dependent Claim
28 words
A method for producing a reversible color change image according to claim 1, wherein the spiro-pyran compound is selected from the group consisting of: 1,3,3-trimethyl-indoline-5-chloro-6''-nitro-benzopyryl-spiran, 1,3,3-trimethyl-indoline-5-methoxy-6''-nitro-benzopyryl-spiran, and 1,3,3-trimethyl-indoline-6''-carboxy-benzopyryl-spiran.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-05-19 | 1978-11-18 | 1979-05-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-19 | 1982-11-18 | 1983-05-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-19 | 1986-11-18 | 1987-05-20 | $7700.00 | Window Closed / Lapsed |