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
  • G03C1/52—Compositions containing diazo compounds as photosensitive substances
  • G03C1/60—Compositions containing diazo compounds as photosensitive substances with macromolecular additives
• • 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
  • G03C1/615—Substances generating bases

Definitions

• the present invention relates to the production of photocopies, and more particularly refers to methods and materials for the production of photocopies.
• a support is coated with a light-sensitive layer containing a diazo compound, exposed, and then developed by the action of alkaline substances.
• the coupling component is coated together with the diazo compound and development is effected by gaseous ammonia.
• aqueous alkaline developer solutions containing the coupling component are used.
• the developing process consists in coupling the unexposed diazo compound with the coupling component to form an azo dye, whereby the image becomes visible.
• the lightsensitive coating must always be acid in order to stabilize the diazo compound, and coupling cannot take place in acid medium. Therefore, thermal development is possible only when the stabilizing acid is removed or the acidity of the coating is strongly reduced to produce the high pH-value necessary for coupling.
• stabilizing salt formers acids which thermally decompose into carbon dioxide or other volatile components have been used. Malonic acid and trichloracetic acid are examples.
• the pH values achieved are not sufficiently high to eilect satisfactory coupling. Contrast is poor.
• one object of the present invention is to provide a photocopying material which overcomes the disadvantages of the prior art.
• Another object is to provide a method of making a photocopy.
• Another object is to provide a method of using said material to produce a copy of an original.
• a process for the thermal development of exposed photocopying material has now been found, which overcomes these disadvantages.
• the process is characterized by the fact that a photocopying material having a lightsensitive layer containing a diazo compound, a coupling component, and at least one 1-hydroxy-napthalene-8-sulr fonamide is developed by heating to temperatures above C.
• the sulfonamide has the formula:
• R represents hydrogen or an alkyl group with one to four carbon atoms
• X represents hydrogen, alkyl, or the group SO NHR, where R represents alkyl, cycloakyl, arylalkyl, or aryl.
• R preferably represents hydrogen, but it may also be a low-molecular weight alkyl group with one to four carbon atoms, for example the methyl, ethyl, propyl, isopropyl or isobutyl group.
• X preferably represents a low molecular weight alkyl group or the group SO NHR' in which R is generally phenyl or a phenyl radical substituted by a. low molecular weight alkyl group.
• the sulfonamide of Formula A splits off a developing agent such as ammonia or amine with the simultaneous formation of the related sultone of Formula B. This creates the alkaline environment necessary for development directly on the photocopying material.
• the sulfonamides of Formula A split off ammonia or amine almost spontaneously within a very narrow temperature range at or very near to its melting point. In most cases a temperature above the melting point is used in the developing device to initiate spontaneous development of the photocopying material. This considerably shortens the developing time and avoids thermal damage to the copying paper.
• low melting compounds In order to develop at low temperatures, compounds with low melting points are used The melting points are greatly influenced by substituents X and R.
• low melting compounds have X or R substituted by an alkyl group with one to four carbon atoms.
• Still lower melting points may be achieved when mixtures of the sulfonamides with one another or with inert substances which depress the melting point are used.
• Aromatic hydrocarbons which are solid at normal temperatures are suitable melting point depressants.
• One such compound is diphenyl.
• the lower arrow of the equation indicates a possible way of preparing the present sulfonamides. This possible way is by reacting the 1,8-naphthosultones of Formula B with ammonia or an amine NH R. When carried out with excess ammonia or amine, the phenol group in the 1-position of the naphthalene ring may be converted directly into the related ammonia salt. It is frequently possible to convert a sultone of Formula B where X is hydrogen into its related sulfonamide and then introduce the substituent X by methods known in naphthalene chemistry.
• the amounts in which the present l-hydroxy-naphthalene-8-sulfonamides are present in the light-sensitive coatings are not critical, but in order to liberate suffieient amounts of ammonia or amine for adequate development, amounts of one to two times the weight of diazo compound are generally used. There is no upper limit to the amount of sulfonamide added. However, for economic reasons, amounts not higher than five times the weight of diazo compound are generally used.
• the degree of suitability of the l-hydroxy-naphthalene- 8-sulfonamides for the present invention may be investigated by preliminary tests, Thus, a particular compound may be heated above its melting point and the presence of volatile amine determined with indicator paper. However, an exposed diazotype paper may also be used instead. The paper is drawn over a vessel provided with a narrow opening and containing the test sulfonamide. When heat is applied, the ammonia or amine is liberated and the azo dye image appears. More expediently, the test compound is brought slowly to its melting point in a reaction vessel containing an unexposed diazotype material and the ammonia or amine formed is transferred to a separate vessel containing the exposed print. The color is rapidly developed when ammonia or amine is liberated at the particular temperature.
• the time that the photocopying material remains in the developing zone of many developing devices is less than 60 seconds, and is preferably under 10 seconds.
• the developing temperature necessary for the photocopying material naturally varies widely not only with the sulfonamide, but also with the kind of photocopying paper and equipment used.
• the temperature must be high enough to sufficiently split off ammonia or amine from the sulfonamide, but it must not be so high that the photocopying paper is damaged or that the diazo compound is decomposed.
• Temperatures above 80 C. are generally required.
• developing temperatures of not more than 30 C. below the melting point are used.
• developing temperatures are chosen in the range beginning about 30 C. below to 30 C. above the melting point of the sulfonamide.
• the temperature should not exceed 200 C.
• plastic and metal foils may be used where higher temperatures are critical.
• the light-sensitive coatings always contain a diazo compound and preferably a compound capable of coupling with the diazo compound.
• Substances suitable for this purpose are those with strong coupling power, such as dihydroxy-naphthalenes andtheir derivatives, phloroglucinol, and compounds which exhibit keto-enol tautomerism, such as pyrazolones, acetoacetic acid arylamides, and dihydroresorcinols.
• the light-sensitive coatings may also contain inorganic or organic acids for stabilization. Examples are hydrochloric acid, boric acid, formic acid, citric acid, tartaric acid, and 1,3,6-naphthalene trisulfonic acid. Acids which decompose at the developing temperature by decarboxylation, for example, with an increase in pH value are preferred.
• trichloroacetic acid which increases the rate of development.
• the process is carried out by coating paper with a solution containing diazo component, coupling component, and the 1-hydroxynaphthalene-8-sulfonamide.
• a solution containing diazo component, coupling component, and the 1-hydroxynaphthalene-8-sulfonamide may be advantageous to coat the paper first with a solution of the 1-hydroxynaphthalene-S-sulfonamide, dry it, and then apply the solution containing only diazo compound and the coupling component.
• the paper may be transparent to heat rays.
• Alcohol-water solvent mixtures are generally used.
• the solutions may also contain one or more of the stabilizing acids, one or more inorganic salts such as zinc chloride or aluminum sulfate, and other additives for accelerating dissolution of the coupling component, for promoting the coupling process (thiourea), or for other purposes (water-miscible organic solvents such as acetone, methyl ethyl ketone, ethylene glycol monomethyl ether).
• anti-yellowing agents and plasticizers may also be present.
• the dried photocopying material is then exposed in conventional manner under a transparent original and then heated to the required developing temperature. This takes place by contact with heat, for example with irons or rollers or static hot air atmospheres, for example in drying cupboards or heating cabinets, by heat convection, for example in a hot air stream, or by heat radiation. These measures may also be combined with one another.
• the present advantages are that no gaseous alkaline developer and no developer solution containing free alkali are required.
• the development of the photocopying material takes place spontaneously and at conditions which do not damage the photocopying paper.
• EXAMPLE 1 A transparent paper was coated with a solution comprising cc. ethyl alcohol and 50 cc. water together with:
• the sensitized paper was exposed under a transparent original and kept in a heating cabinet for a short time at 120140 C. Blue images with very good contrast were obtained.
• the compound of Formula No. 1 was prepared by covering 30 grams of 1,S-naphthosultone-4-sulfonic acid anilide (melting point 147 C.) with cc. of concentrated ammonia water and gently heating on a water bath. The anilide rapidly dissolved and the compound of Formula 1 was precipitated as a crystalline mass. After recrystallization from methanol, 22.5 grams with a melting point of 128 C. (decomposition) were obtained.
• the compounds of Formulas 2, 3, 4, and 5 in the table were prepared analogously. When preparing compounds 4 and S, the presence of water was not necessary. These compounds may be prepared by reaction of the related sultones with excess n-propylamine or n-butylamine.
• EXAMPLE 2 A photocopying base paper was coated with a six-toe ght percent solution of the compound of Formula 6 in dimethylformamide and dried for about three minutes at 70 C. This was then coated with a solution containing 100 cc. water and:
• T able--C ontinued Formula Melting Point 4-metl1yl-1-hydroxynaphthalenc-S-npropylsulphonamidc.
• a heat-developable photocopying material which comprises:
• a photosensitive layer coated on said support said layer comprising a photosensitive diazonium compound, a dye-forming coupling component, and at least one 1-hydroxy-naphthalene-B-sulfonamide having the formula:
• R is a member selected from the group consisting of hydrogen and alkyl with one to four carbon atoms
• X is a member selected from the group consisting of hydrogen, alkyl with one to four carbon atoms, and the group -SO NHR' where R is a member selected from the group consisting of alkyl, cycloalkyl, aralkyl, and aryl, said sulfonamide being heat-decomposable at temperatures above 80 C. to liberate a developing agent for said layer.
• a material in accordance with claim 1 in which said sulfonamide is l-hydroXy-naphthalene-8-sulfonic acid-npropylamide-4-sulfonic acid anilide.
• a method of making a photocopy of an original which comprises the steps of:
• a photocopying material comprising a support coated with a photosensitive layer including photosensitive diazonium compound, dye-forming coupling component, and at least one 1-hydroxy-naphthalenc-S-sulfonamide having the formula:
• R is a member selected from the group consisting of hydrogen and alkyl with one to four carbon atoms
• X is a member selected from the group consisting of hydrogen, alkyl with one to four carbon atoms, and the group SO NHR, where R is a member selected from the group consisting of alkyl, cycloalkyl, arylalkyl, and aryl, said sulfonamides being heat-decomposable at temperatures above C. to liberate a developing agent for said layer;
• heating temperature is at least 80 C. and not greater than 200 C.
• NORMAN G. TORCHIN Primary Examiner.
• A. D. RICCI Assistant Examiner.

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

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Cited By (4)

• 0
  • GB GB1052978D patent/GB1052978A/en active Active
• 1963
  • 1963-11-26 DE DEK51457A patent/DE1229844B/de active Pending
• 1964
  • 1964-11-24 US US413610A patent/US3272627A/en not_active Expired - Lifetime
  • 1964-11-25 BE BE656241A patent/BE656241A/xx unknown

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