EP0041984B1 - Diazophotographisches system - Google Patents

Diazophotographisches system Download PDF

Info

Publication number
EP0041984B1
EP0041984B1 EP81900099A EP81900099A EP0041984B1 EP 0041984 B1 EP0041984 B1 EP 0041984B1 EP 81900099 A EP81900099 A EP 81900099A EP 81900099 A EP81900099 A EP 81900099A EP 0041984 B1 EP0041984 B1 EP 0041984B1
Authority
EP
European Patent Office
Prior art keywords
layer
leuco
leuco dye
feature
layer according
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP81900099A
Other languages
English (en)
French (fr)
Other versions
EP0041984A4 (de
EP0041984A1 (de
Inventor
Kenneth G. Gatzke
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
3M Co
Original Assignee
Minnesota Mining and Manufacturing Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Minnesota Mining and Manufacturing Co filed Critical Minnesota Mining and Manufacturing Co
Publication of EP0041984A1 publication Critical patent/EP0041984A1/de
Publication of EP0041984A4 publication Critical patent/EP0041984A4/de
Application granted granted Critical
Publication of EP0041984B1 publication Critical patent/EP0041984B1/de
Expired legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
    • G03C1/00—Photosensitive materials
    • G03C1/72—Photosensitive compositions not covered by the groups G03C1/005 - G03C1/705
    • G03C1/73—Photosensitive compositions not covered by the groups G03C1/005 - G03C1/705 containing organic compounds
    • G03C1/732—Leuco dyes
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
    • G03C1/00—Photosensitive materials
    • G03C1/52—Compositions containing diazo compounds as photosensitive substances
    • G03C1/61—Compositions containing diazo compounds as photosensitive substances with non-macromolecular additives

Definitions

  • a novel light sensitive, heat developable imaging system incorporating a diazonium salt and a leuco dye in a binder is disclosed.
  • the system is useful, for example, as a microfilm duplicating sheet or a heat sensitive recording material.
  • U.S. Patent 3,390,997 discloses a light-sensitive admixture of an alkylthio, benzylthio, 2-phenyl- hydrazino or alkoxycarbonyl derivative of a triphenylmethane compound (a "leuco dye") and a selected non-volatile nitrogen-containing compound which functions as a photooxidant useful as an imaging system.
  • the light sensitive compounds ofthe present invention differ significantly from those of the patent which contain only trivalent nitrogen atoms.
  • the present invention requires elevated temperatures 82°C to 193°C [180°F to 380°F] for image development, whereas the patent disclosure is of a room temperature developing system.
  • U.S. Patent 3,445,233 relates to a composition which may contain a polymeric binder in addition to three active ingredients which are an organic nitrogen-containing color generator, a photooxidant, and diazonium ' compound.
  • the photooxidant oxidizes the color generator in the presence of radiation. There is no reaction between the color generator and the diazonium salt when irradiated.
  • An imaging system comprising a polymeric binder, a bleachable dye or leuco dye, a photosensitive diazonium salt, and at least 0.1 mole nitrate ion/1.0 mole dye is described in assignee's copending patent application, International Publication No. WO 81/01755 (European Patent Application No. 81 900 234.6) published 25 June 1981.
  • the present invention relates to a light sensitive, heat developable imaging system comprising a polymeric binder resin, a leuco dye, and a diazonium salt.
  • a polymeric binder resin e.g., polyethylene glycol dimethacrylate copolymer
  • a leuco dye e.g., polyethylene glycol dimethacrylate copolymer
  • a diazonium salt e.g., organic or inorganic acid
  • oxidizing anion including nitrate ion
  • nitrate ion is a necessary component of the present invention as it is in assignee's copending application mentioned above. If any nitrate ion is present, it is in amounts of less than 0.1 mole nitrate/1.0 mole dye. Other oxidizing anions and compounds may be present in greater or lesser amounts, but are not essential in the practice of the present invention.
  • the leuco dye (a clear to faintly colored material), the diazonium salt and the polymeric binder resin are incorporated in a solvent system and cast on any substrate such as paper, polymeric filmn such as polyester, glass, metal, ceramics and the like.
  • the diazonium salt Upon irradiation by light, the diazonium salt is destroyed.
  • the subsequent application of heat to the coating results in oxidation of the leuco dye by the diazonium salt to a colored form in the non-light struct portion of the coating. A positive-acting image is thus produced since color is generated where no light has contacted the coating.
  • reaction appears to be an oxidation of the leuco dye during heat development by the diazonium salt which has not been decomposed by incident radiation.
  • the present invention provides a light-sensitive, positive-acting, heat developable layer on a substrate, said layer comprising a polymeric binder, a leuco dye, and a diazonium salt, the dry ingredients of said layer characterized by including at least 25 percent by weight of a polymeric binder, at least 0.3 percent by weight of a leuco dye capable of being oxidized to a colored form, a sufficient amount of a photosensitive diazonium salt to oxidize said leuco dye, upon heating, to a colored form in non-light struck portions of said layer, and less than 0.1 mole nitrate ion per 1.0 mole leuco dye.
  • Any natural or synthetic polymeric binder may be used in the practice of the present invention.
  • Organic polymeric resins preferably thermoplastic resins (although thermoset resins may be used), are generally preferred.
  • the most preferred resins are polyvinyl acetate and polyvinyl chloride copolymers.
  • Such resins as polyvinyl acetals, polyesters, polyvinyl resins, polyvinylpyrrolidone, polyesters, polycarbonates, polyamides, polyvinyl butyral, polyacryllates, cellulose esters, copolymers and blends of these classes of resins, and others have been used with particular success.
  • Natural polymeric materials ' such as gelatin and gum arabic may also be used.
  • the resin should be able to withstand those conditions. Generally it is preferred that the polymer not decompose or lose its structural integrity at (147°C) (300°F) for 60 seconds and most preferred that it not decompose or lose its structural integrity at (193°C) (380°F) for 5 minutes. Also, polymers must be compatible with the other components and solvents, in addition to having a reasonably low softening point for processability. Such polymers desirably are permeable to trapped gases.
  • the selected binder must be transparent or translucent and be either clear or lightly colored. This will ensure an obvious contrast with colored areas (non-light struck) after heat development.
  • the binder may serve a number of additionally important purposes in the constructions of the present invention.
  • the imageable materials may be protected from ambient conditions such as moisture.
  • the consistency of the coating and its image quality are improved.
  • the durability of the final image is also significantly improved.
  • the binder should be present as at least 25% by weight of ingredients in the layer, more preferably as at least 50% by weight and most preferably as at least 70% by weight of dry ingredients (i.e., excluding solvents in the layer).
  • Leuco dyes are well known in the art. These are colorless or lightly colored dyes which when subjected to an oxidation reaction form a colored dye. These leuco dyes are described in the literature (e.g., Mees and James, “The Theory of the Photographic Process", 3rd Edition, published 1966, by Macmillan Co. (N.Y.), see pages 283-4, 390-1; and J. Kosar, "Light-Sensitive Systems", published 1 d65, by Wiley and Sons, Inc. (N.Y.), see pages 367, 370-380, 406). Amongst the best known leuco dyes are leuco crystal violet (LCV) and Leuco malachite green (LMG).
  • LCV leuco crystal violet
  • LMG Leuco malachite green
  • leuco dyes which can be converted to colored dyes by oxidation are useful in the practice of the present invention.
  • Acid or base sensitive dyes such as phenolphthalein and other indicator dyes are not useful in the present invention unless they are also oxidizable to a colored state.
  • Indicator dyes would only form transient images or would be too sensitive to changes in the environment.
  • the leuco dyes which have been specifically shown to work in the present invention are discussed in detail below, including their formulae; and include but are not limited to the following:
  • the leuco dyes of the present invention become colored due to oxidation, that is, they have absorbance after coloration in the visible portion of the electromagnetic spectrum (approximately 400 to 700 nm).
  • the leuco dye should be present as at least 0.3% by weight of the binder layer, preferably at least 1 % by weight, and mist preferably at least 2% to 10% or more by weight of the dry weight of the imageable layer.
  • temperatures should, of course, not be used during manufacture which would colorize the layer or decompose the diazonium salts. Some slight colorization is tolerable, with the initial leuco dye concentrations chosen so as to allow for anticipated colorization. It is preferred, however, that little or no leuco dye be colorized during forming or coating so that more standardized layers can be formed.
  • the coating or forming temperature can be varied. Therefore, if the anticipated development temperature were, for example, 167°C, the drying temperature could be 138°C, and it would not be desirable for the layer to gain 20% of its optical density at the drying temperature in less than 4-5 minutes. Such a gain would be tolerable by correspondingly increasing the amount of leuco dye.
  • colorizable dye present in the colorizable layer of the present invention to provide an increase in optical density upon development of at least 0.2, more preferably 0.6, and most preferably 1.0 or greater. These increases can be measured at the development temperatures for the imaging materials, e.g., 132°C for 60 seconds.
  • the preferred limitation of at least 0.2 gain in optical density or absorbance of colorless light at 132°C for 60 seconds is based on the assumption of a development temperature of 132°C. For an anticipated higher or lower development temperature, the 0.2 gain in optical density or absorbance should occur at that development temperature within a reasonable period of time.
  • a reasonable development temperature range is between 82°C and 193°C and a resonable dwell time is between 5 seconds and 5 minutes, preferably at between 105°C and 167°C and for 10 to 180 seconds, with the longer times most likely accosicated with the lower development temperatures. Therefore, all of the absorbance characteristics are applicable to the generally useful development range of 82°C to 193°C.
  • Light sensitive diazonium salts are well known in the art. These salts comprise a light sensitive aromatic nucleus with an external diazonium group and an anion associated therewith (e.g., J. Kosar, "Light-Sensitive System”, published 1965, by John Wiley and Sons, Inc. (N.Y.), see pages 202-214; and P. Glafkides, "Photographic Chemistry", Vol. II, published 1960, by Fountain Press (London), see pages 709-725). They may be generally represented by the formula:
  • Ar is an aromatic nucleus
  • X- is an anion
  • Any anion may be used in the diazonium salt.
  • Anions as diverse as zinc chloride, tri-isopropyl naphthalene sulfonate, fluoroborate (i.e., BF4-), and bis(perfluoroalkylsulonyl)methides may be used.
  • the change in anions may affect the speed of the imaging layer, but not its function.
  • Any light sensitive aromatic diazonium nucleus as known in the art, may also be used in the practice of the present invention.
  • diazonium nuclei particularly those belonging to the classes pyrrolidine, morpholine, aniline, and diphenyl amine and its polymers are well known in the art and include, for example, P-anilinobenzene; N-(4-diazo-2,4-dimethoxy phenyl)pyrrolidine; 1-diazo-2,4-diethoxy-4-morpholino benzene; 1-diazo-4-benzoyl amino-2,5-diethoxy benzene; 4-diazo-2,5-dibutoxy phenyl morpholino; 4-diazo-1-dimethyl aniline; 1-diazo-N,N-dimethyl aniline; 1-diazo-4-N-methyl-N-hydroxyethyl aniline; etc.
  • Other materials which may be useful in the formulations of the present invention include reducers and complexors, plasticizers and polyketones, stabilizers, surfactants, antistatic agents, coating aids, oxidizing materials (other than nitrate ion which may be present only in amounts less than 0.1 mole nitrate to 1.0 mole dye), inhibitors, lubricants, flexibilizers, fillers and the like.
  • Solution A comprised .020 g phthalic acid, .010 g catechol, .10 g Phenidone A (1-phenyl-3-pyrazolidone), .200 g aromatic ketone resin, .200 g polymeric plasticizer (ter, 2,4-trimethylpentane, 1,3-diol adipate 2-ethylhexanol terminated [900-1100 molecular weight]) and 1.060 g methyl ethyl ketone (MEK) for a total weight of 1.5 g.
  • MEK methyl ethyl ketone
  • Solution B comprised .051 g leuco crystal violet (4,4',4"-methylidynetris-(N-N-dimethylaniline)), .046 g leuco malachite green (p,p'- benzylidenebis-(N,N-dimethylaniline)), and 1.429 g tetrahydrofuran (THF), for a total weight of 1.5 g.
  • Phthalic acid is useful in these formulations to stabilize the coating solution by preventing the diazonium salt from reacting before development.
  • the binders of examples 12, 13 and 14 decrease progressively in molecular weight which correlates with a progressive decrease in softening points of these resins. It is of note that the A Density increases as the softening temperature of the resin decreases, reflecting better reacting conditions in softer resins.
  • the binders of examples 15 and 16 are resins with acid content, a factor which did not enhance the A Density.
  • Tetrachlorophthalic anhydride 2,4,4-trimethylpentyl-bis-(2-hydroxy-3,5-dimethylphenyl)methane (TBHDM), 2,6-bis(2'-hydroxy-3'-tert butyl-5'-methyl benzyl)-4-methylphenol, and 2,2'-methylenebis(4-methyl-6-tert butylphenol) showed some degree of usefulness in increasing the A Density compared to experiments without these materials.
  • Phenidone A (1-phenyl-3-pyrazolidone) and ascorbic acid greatly depressed both the Dmin and Dmax values and when studied at lower levels of concentration (.01 g) were found to be useful in depressing the Dmin.
  • plasticisers and polyketones effectively lower the softening point of the polymeric binder, thereby increasing the rate of development. They have been found to be most effective in the higher softening resins (i.e. resins of higher molecular weight) as might be expected.
  • DDBF diphenylamine-4-diazonium borofluoride
  • 1-diazo-2,5-diethoxy-4-morpholino benzene borofluoride and 2,5-diethoxy-4-(p-tolyethio)benzene diazonium chloride 1/2 zinc chloride gave the highest Dmax values but the A Density values were not improved due to corresponding higher Dmin values.
  • Examples 130, 131, 135 and 139 gave borderline commercial results, the Density values being respectively 1.16, 1.00, 1.02 and .94. The resolution in these cases is excellent, being in the order of 400 line pairs per mm.

Landscapes

  • Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • General Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Non-Silver Salt Photosensitive Materials And Non-Silver Salt Photography (AREA)
  • Heat Sensitive Colour Forming Recording (AREA)

Claims (9)

  1. Positivwirkende lichtempfindliche Bilddarstellungsschicht auf einem Substrat, wobei die genannte Schicht ein polymeres Bindemittel, einen Leukofarbstoff und ein Diazoniumsalz enthält und die Trockenbestandteile der Schicht dadurch gekennzeichnet sind, daß sie in der Wärme entwickelbar sind und mindestens 25 Gew.% eines polymeren Bindemittels, mindestens 0,3 Gew.% eines in einen farbigen Zustand oxidierbaren Leukofarbstoffes, eine bei Erwärmung zum Oxidieren des Leukofarbstoffes in nicht lichtbeaufschlagten Teilen der Schicht genügende Menge eines lichtempfindlichen Diazoniumsalzes und weniger als 0,1 Mol Nitration pro 1,0 Mol Leukofarbstoff enthalten.
  2. 2. Schicht nach Anspruch 1, dadurch gekennzeichnet, daß der Leukofarbstoff 1 bis 10 Gew.% der Trockenbestandteile der genannten Schicht ausmacht.
  3. 3. Schicht nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß der Leukofarbstoff in einer so hohen Konzentration vorhanden ist, daß er bei seiner Entwicklung die optische Dichte um mindestens 0,2 erhöht.
  4. 4. Schicht nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß der Leukofarbstoff in einer so hohen Konzentration vorhanden ist, daß er bei seiner Entwicklung die optische Dichte um mindestens 0,6 erhöht.
  5. 5. Schicht nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß der Leukofarbstoff in einer so hohen Konzentration vorhanden ist, daß er bei seiner Entwicklung die optische Dichte um mindestens 1,0 erhöht.
  6. 6. Schicht nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß der Leukofarbstoff aus der Klasse ausgewählt ist, die aus Leukokristallviolett und Leukomalachitgrün besteht.
  7. 7. Schicht nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß sie das Diazoniumsalz 1-Diazo-2,5-diethoxy-4-morpholinobenzolborfluorid enthält.
  8. 8. Schicht nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß sie ein Bindemittel enthält, daß aus den Klassen ausgewählt ist, die aus den polyvinylchlorid- bzw. den Polyvinylacetatharzen bestehen.
  9. 9. Schicht nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß das Bindemittel einer Menge von mindestens 25 Gew.% der Trockenbestandteile der Schicht vorhanden ist.
EP81900099A 1979-12-07 1980-10-27 Diazophotographisches system Expired EP0041984B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US10114379A 1979-12-07 1979-12-07
US101143 1979-12-07

Publications (3)

Publication Number Publication Date
EP0041984A1 EP0041984A1 (de) 1981-12-23
EP0041984A4 EP0041984A4 (de) 1982-05-10
EP0041984B1 true EP0041984B1 (de) 1984-09-19

Family

ID=22283224

Family Applications (1)

Application Number Title Priority Date Filing Date
EP81900099A Expired EP0041984B1 (de) 1979-12-07 1980-10-27 Diazophotographisches system

Country Status (4)

Country Link
EP (1) EP0041984B1 (de)
JP (1) JPH0143938B2 (de)
DE (1) DE3069247D1 (de)
WO (1) WO1981001756A1 (de)

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5151942A (de) * 1974-10-31 1976-05-07 Naigai Ink Mfg Co Ltd

Family Cites Families (23)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2411811A (en) * 1945-02-01 1946-11-26 Gen Aniline & Film Corp Light-sensitive materials
US2560137A (en) * 1948-12-21 1951-07-10 Gen Aniline & Film Corp Diazotype photoprinting material
US2756144A (en) * 1951-04-25 1956-07-24 Brown Allen Chemicals Inc Photochemical multicolor printing of textile and the like
US2772284A (en) * 1951-10-20 1956-11-27 Du Pont Solvent-soluble, complex, phthalocyanine-yielding compounds
BE546818A (de) * 1955-04-06
US3215529A (en) * 1960-07-18 1965-11-02 Kalvar Corp Color photographic material
NL292007A (de) * 1962-04-27
US3390997A (en) * 1964-04-29 1968-07-02 Du Pont Photosensitive composition comprising a triphenylemethane derivative and a nitrogen-containing photo-oxidant
US3460964A (en) * 1964-11-19 1969-08-12 Eastman Kodak Co Heat-sensitive recording element and composition
US3445233A (en) * 1965-04-16 1969-05-20 Du Pont Photosensitive composition
DE1522496A1 (de) * 1966-02-12 1969-09-11 Kalle Ag Lichtreprographische Kopiermasse und damit beschichtetes Kopiermaterial
GB1204917A (en) * 1967-11-14 1970-09-09 Howson Algraphy Ltd Photographic printing plates
DE1931482A1 (de) * 1968-11-18 1970-06-04 Matsushita Electric Ind Co Ltd Lichtempfindliche Massen und Folien
AT289152B (de) * 1968-12-09 1971-04-13 Kalle Ag Lichtempfindliches Kopiermaterial zum Herstellen einer Flachdruckform
US3620739A (en) * 1969-08-13 1971-11-16 Eastman Kodak Co Photographic process and element for the production of add-on images
US3992450A (en) * 1971-04-30 1976-11-16 E. I. Du Pont De Nemours And Company 2,3-Disubstituted-1-indanones
US3801319A (en) * 1972-06-21 1974-04-02 Xerox Corp Imaging method utilizing chemical reactivities of photoexcited states of aromatic hydroxy compounds
US4017313A (en) * 1974-09-30 1977-04-12 E. I. Du Pont De Nemours And Company Photosensitive composition containing a leuco dye, a photosensitizer, an aromatic aldehyde and a secondary or tertiary amine and the use thereof in a direct-print process
CH593807A5 (de) * 1975-01-27 1977-12-15 Ciba Geigy Ag
DE2655553A1 (de) * 1976-12-08 1978-06-15 Licentia Gmbh Mittels einer diazoniumverbindung sensibilisierte waesserige loesung eines polymerisates sowie verwendung einer solchen loesung zur herstellung von leuchtschirmen fuer farbbildkathodenstrahlroehren
JPS53102038A (en) * 1977-02-18 1978-09-06 Ricoh Co Ltd Mutlchromatic copying and recording material
US4097288A (en) * 1977-02-25 1978-06-27 Lawton William R Heat sensitive recording composition containing a complexed phenolics and a spiropyran or leuco lactone
JPH05151942A (ja) * 1991-11-28 1993-06-18 Iwasaki Electric Co Ltd メタルハライドランプ装置

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5151942A (de) * 1974-10-31 1976-05-07 Naigai Ink Mfg Co Ltd

Also Published As

Publication number Publication date
EP0041984A4 (de) 1982-05-10
EP0041984A1 (de) 1981-12-23
JPH0143938B2 (de) 1989-09-25
JPS56501503A (de) 1981-10-15
WO1981001756A1 (en) 1981-06-25
DE3069247D1 (en) 1984-10-25

Similar Documents

Publication Publication Date Title
US4370401A (en) Light sensitive, thermally developable imaging system
US4394433A (en) Diazonium imaging system
US3152904A (en) Print-out process and image reproduction sheet therefor
US4373020A (en) Decolorizable imaging system
EP0019219B1 (de) Verbesserte Photobildsysteme mit cyclischen Hydraziden
US4196002A (en) Photothermographic element containing heat sensitive dye materials
CA1174887A (en) Visible light sensitive, thermally developable imaging system including a leuco dye, nitrate salt, photoinitiator and sensitizing dye
US4487826A (en) Diazotype heat development recording medium with hydrophobic salt of alkyl substituted guanidine
US4201590A (en) Heat sensitive reactive products of hexaarylbiimidazole and antihalation dyes
US3655383A (en) Method for reproducing images of a solid photocatalyst with an oxidizing agent
US4201588A (en) Radiation sensitive co(III)complex photoreduction element with image recording layer
US3615481A (en) Leuco dye/hexaarylbiimidazole thermally activated imaging process
US4460677A (en) Visible light sensitive, thermally developable imaging systems
US3589901A (en) Method of making a heat developable sheet containing mercury lens
US3679415A (en) Diazotype photographic elements having extended exposure latitude with specific u-v absorber
US4587211A (en) Photothermographic stabilizers for syringaldazine leuco dyes
US3753395A (en) Photo-thermographic recording process with 5-pyrazolane
US3630736A (en) Leuco dye/hexaarylbiimidazole compositions and processes
EP0041984B1 (de) Diazophotographisches system
US4094687A (en) Heat-sensitive recording composition
US3856531A (en) Photographic compositions and processes
US3146348A (en) Heat-sensitive copy-sheet
US3526506A (en) Heat reactive,light desensitizing compositions
EP0273590B1 (de) Stabilisierung von Ketazinfarbstoffen
US3767409A (en) Photographic triorganophosphine-azide dye forming composition and article

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Designated state(s): DE FR GB

17P Request for examination filed

Effective date: 19811021

RBV Designated contracting states (corrected)

Designated state(s): DE FR GB SE

RBV Designated contracting states (corrected)

Designated state(s): DE FR GB

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Designated state(s): DE FR GB

REF Corresponds to:

Ref document number: 3069247

Country of ref document: DE

Date of ref document: 19841025

ET Fr: translation filed
PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
REG Reference to a national code

Ref country code: GB

Ref legal event code: 732

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 19940916

Year of fee payment: 15

Ref country code: DE

Payment date: 19940916

Year of fee payment: 15

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 19940927

Year of fee payment: 15

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Effective date: 19951027

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 19951027

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Effective date: 19960628

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Effective date: 19960801

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST