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
  • G03C1/54—Diazonium salts or diazo anhydrides

Definitions

• the invention relates to a proce s s for making positive diazotype copies and to light-sensitive diazotype material suited for carrying out this process.
• the determination of the endpoint of the exposure is of importance. In practice this is sometimes done in the positive diazotype process by means of visual observation.
• the visual determination is uncertain in the case of exposure with non-fluorescent lamps; upon exposure of the usual diazotype materials with actinically fluorescent lamps the observed endpoint lies too far before the point at which the diazotype material has received the exposure desired in practice. This being so, in practice the exposure is continued at random for a short time, but this naturally involves errors.
• p-diazodiphenyl-amine a diazo compound which is known to be particularly suited for visual endpoint determination, is employed.
• an actinically fluorescent mercury vapour lamp is used as light-source for the image-wise exposure, while for copying use is made of a diazotype material the light-sensitive layer of which contains a diazo compound of the general formula:
• R represents an alkyl group with at most 4 carbon atoms
• R represents an alkyl group with at most 4 carbon atoms oran aralkyl group with at most-7 carbon atoms
• R represents an alkyl group with at most 4 carbon atoms.
• the visually observable endpoint of the exposure lies particularly near to the point at which the diazotype material TL/5 type lamp of N.V. Philips Gloeila-mpenfabriek,
• wavelengths contains a variety of wavelengths, including emissions in a continuous spectrum in the range between about 3000 and 4700 Angstrom uni-ts with the maximum emission at about 3655 Angstrom units and certain emissions in the green-yellow range above 5000 Angstrom units, its prevailing wavelengths perceptible to the human eye lie in the blue range between 4000 and 4700 Angstrom units.
• the diazo compounds in which the substituents R R and/or R contain 3 or 4 carbon atoms are better suited for the one-component diazotype process while those in which these substituents are methyl and/or ethyl groups are to be preferred for the two-component diazotype process.
• R is an aralkyl group or if, in the absence of an aralkyl group, one of the substituents R R or R is an alkyl group of 3 or 4 carbon atoms, the compound is already suited for the one-component diazotype process. Consequently, the number of compounds suited for the one-component process is relatively large. With the compounds suited for the one-component process suitable two-component di-azotype materials may also be obtained.
• azo components of poor coupling activity and/ or coupling-retarding agents are preferably employed in the material.
• the substituents are alkyl groups with three or four carbon atoms (for example, normal butyl or isobutyl)
• the diazo compounds may have a capillary-active eifect. In aqueous solution these compounds penetrate deeply into the usual base-papers upon sensitization. The visual determination of the endpoint of the exposure is thus made diflicult and the light-sensitivity of the diazotype material, as well as the strength of the copies, decreases.
• Such diazo compounds are, however, better suited for sensitizing film layers, for example, superficially saponified cellulose-ester layers, and natural tracing paper.
• the light-sensitive material for the new process may of course contain mixtures of diazo compounds according Mixtures with other diazo compounds may also be suitable. In that case, however, the eflect is smaller.
• Diazotype material which is particularly suited for carrying out the process according to the invention contains as the light-sensitive compound a diazo compound of the type of 1-diazo4-(alkyl) (benzyl)amino-3-alkoxybenzene, the two alkyl groups of which contain together at most 3 carbon atoms.
• diazo compounds have various attractive properties: they are suificiently soluble, their solutions do not penetrate deeply into the paper; they keep well; they are able to form black azo-clyestufis upon development of diazotype material sensitized therewith.
• the diazo compounds with a benzyl group for use in the process according to the invention, give entirely colourless photochemical decomposition products upon exposure.
• Diazotype material particularly suited for the process contains, as the light-sensitive compound, 1-diazo-4-din-propylamino-3-ethoxybenzene; the compound is readily available.
• the azoalyestuif images obtained by development of these materials with a diazotype developer containing phloro-glucinol are more resistant to change of pH; in
• the diazo compounds according to the invention are readily available.
• the starting material is o-anisidine or o-phenetidine; for the compounds with other alkoxy groups it is o-nitrophenol, which is alkylated and subsequently reduced.
• the amino group is then alkylated.
• the resulting o-alkoxydialkylaniline is thereupon nitrosated in acetic acid, the nitroso compound is reduced, for example with hydrochloric acid and aluminium powder, and the p-amino compound is diazotized.
• the o-olkoxy-dialkylaniliue may be caused to couple with an actively coupling diazo compound, for example, 1 diazo 2.5 dichlorobenzene.
• diazo compound for example, 1 diazo 2.5 dichlorobenzene.
• the azo-dyestulf obtained is reduced, the 2.5-dichloroaniline thus formed is separated from the p.amino-oalkoxy-dialkylaniline formed at the same time, and the latter is diazotized.
• the diazo compound is obtained from the diazotizing liquid by precipitation in the form of diazonium salt, for example a diazonium borofluoride or a diazonium zinc chloride double salt.
• diazonium salt for example a diazonium borofluoride or a diazonium zinc chloride double salt.
• R and R may be the same or different alkyl groups. Their carbon chain may or may not be branched, provided their presence in the molecule of the diazo compound in the places indicated is possible from the point of view of structure of the molecule.
• Example 1 White base-paper of 80 g./m. for the diazotype process is sensitized with a solution of:
• the sensitized surface contains approximately 0.5 millimole of the diazo compound per m
• a sheet of the diazotype paper is exposed under a film positive of a pencil line-drawing on the outer surface of a glass cylinder in the axis of which is placed an actinically fluorescent low-pressure mercury vapour lamp of the TL/ type, of N. V. Philips Gloeilampenfabriek, Eindhoven.
• the sheet of diazotype paper, together with the line-positive, is held against the cylinder surface by means of an apron.
• the distance from the outer surface of the cylinder to the centre of the lamp is 9.5 cm.
• the progress of the bleaching of the yellow diazo compound in the diazotype surface can easily be observed visually, for example, from the direction of the lamp; the endpoint of the observation is reached after approximately 55 seconds. The exposure is stopped at this point.
• the latent diazotype copy obtained is developed by applying on its image surface a layer of approximately 8 g./n1. of the following developer:
• Example II Natural tracing paper of g./m. is sensitized with a solution of:
• Example 111 White base-paper of 80 g./m.
• the sensitized surface contains approximately 0.5 millimole of the diazo compound per m
• a sheet of the diazotype material is exposed as in Example I.
• the latent diazotype copyobtained is developed in ammonia vapour.
• the developed copy shows a strong red azo-dyestuff image with the fog most desirable in practice.
• a process for making diazotype copies which comprises imagewise exposing to the light of an actinically fluorescent mercury vapor lamp a diazotype sheet material having a light-sensitive layer containing a 1-diazo-4- alkylbenzyl amino-B-alkoxy-benzene in which the alkyl groups together contain from 2 to 3 carbon atoms, said lamp being one having emissions in a continuous spectrum in the range between about 3000 and 4700 A. with the maximum emission at about 3655 A. and having certain emissions in the range above 5000 A. and its prevailing wavelengths perceptible to the human eye being in the range between 4000 and 4700 A.
• a diazotype material comprising a sheet-like support carrying a light-sensitive layer containing as its principal light-sensitive constituent a 1-diazo-4-alkylbenzy1 amino- 3-a1koxybenzene in which the alkyl groups together contain from 2 to 3 carbon atoms, said layer upon being exposed to the light of an actinically fluorescent meroury vapor lamp attaining a stage of optimum exposure when a portion of said layer being exposed to said light appears to the human eye to :have become bleached by the exposure, said lamp being one having emissions in a continuous spectrum in the range between about 3000 and 4700 A. with the maximum emission at about 3655 A. and having certain emissions in the range above 5000 A. and its prevailing Wavelengths perceptible to the human eye being in the range between 4000 and 4700 A.

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

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  • NL NL110414D patent/NL110414C/xx active
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  • BE BE564343D patent/BE564343A/xx unknown
• 1958
  • 1958-01-04 DE DEC16042A patent/DE1092767B/de active Pending
  • 1958-01-07 FR FR1191365D patent/FR1191365A/fr not_active Expired
  • 1958-01-15 CH CH5470458A patent/CH366743A/de unknown
  • 1958-01-15 GB GB1471/58A patent/GB867629A/en not_active Expired
  • 1958-02-04 US US713105A patent/US3081166A/en not_active Expired - Lifetime

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