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

Definitions

• the present invention pertains to light sensitive diazotype materials having fast printing speed and being capable of yielding images of high density, and more particularly to such materials in which the light sensitive component is located on the base in a layer comprising a polyvinyl ester having finely divided silica dispersed rherethrough.
• diazonium compound having such a high light sensitivity that it may be used in a concentration which will give the required image density while still permitting complete burn-out in the whites in the desired period of time.
• diazos of widely varied chemical structures have been proposed, synthesized and tested in the diazotype process.
• the stabilized diazos derived from N,N-disubstituted p-phenylenediamines appear to offer the best compromise between high light sensitivity and greater dye density, on the one hand, and the other requisite features such as Water solubility in coating solutions, stability to decomposition and/ or precoupling, fastness properties and the like, on the other hand.
• Another tack has been the used additives in the diazotype coating solution to increase the burn-out sensitivity of the diazo in the light struck areas.
• diazotype coating solution For this purpose there have been proposed such compounds as anthraquinone disulfonic acid, ketonic organiccompounds and the like. It is evident that this phenomenon, if successful, would permit more diazo to be used in the sensitized layer and thereby result in a higher density in the image areas with no sacrifice in printing speed. Unfortunately, this approach has met'with but limited" success, the results not being commercially satisfactory on a quality or cost basis.
• 2,566,709 proposes to produce the same improvement in the diazotype system of photoreproduction by the incorporation of colloidal silica in a dispersed state in a diazotype sensitizing solution.
• the latter procedure has the very important added economic advantage of eliminating a separate coating step.
• Rub-off, or powdering-oif, as the name implies involves the tendency of the silica particles to be removed during manufacture and end use of the diazotype materials.
• the silica layer acts as a chromatographic separator toward the several ingredients present in a typicaldiazo coating solution. This re sults in poorer stability, poorer fade resistance, and, in the case of the black line (which uses a multiplicity of coupling components) off-colored blacks. It has been stated that the use of the silica layers in the above patents enhanced brightness and density. It is to be noted, however, that the degree of improvement when weighed against the aforesaid objections, the increased cost and extra eiforts is disappointingly small.
• the water insoluble polymers may be a polyvinyl ester per se, such as polyvinyl acetate, polyvinyl chloride or the like, or copolymers of a vinyl ester, suchas vinyl chloride, vinyl acetate or the like with another vinyl compound copolymerizable with such ester, i. e., acrylic acid, styrene or the like.
• the vinyl ester in such copolymers will range from to 40 parts by weight.
• These polymers and copolymers are employed in the form of aqueous dispersions in which the solids content is 40-55% by Weight, Such polymers are readily obtainable in the open market.
• the silica which we use in our dispersions may be either colloidal in character or may be of a coarser grade, i. e., ranging from 1 to 5 microns in. size. We find that we obtain best results with the coarser particles and so prefer their use.
• diazos examples are those derived from .N,N-diethyl-p-phenylenediamine; N-benzyl N ethyl p phenylenediamine; N-ethyl-p-phenylenediamine; N phenyl p phenylenediamine; N,N-diethyl-2- ethoxy p-phenylenediamine; N-ethyl-Z-methyl-p-phenylenediamine; N,N bis(fl hydroxyethyl) p-phenylenediamine; N fi-hydroxyethyl-N-methyl-p-phenylenediamine and the like. According to customary procedure these diazos are used in the form of salts stabilized with zinc chloride, tin chloride, cadmium chloride and the like.
• any of the usual coupling components are satisfactory for our purpose.
• couplers are 2,5- xylenol; 2,3-dihydroxynaphthalene; 1,8-dihydroxynaphthalene; resorcinol, octyl resorcinol; p-methyl-N-phenyl pyrazolone; the amide of u-resorcylic acid; 2-hydroxynaphthalene-3,6'disu1fonic acid; H acid; acetyl acetanilide; 2,3-dihydroxynaphthalene-6-sulfonic acid and the like.
• Other couplers are mentioned in the Van der Grinten article supra.
• the coating solution in addition to the polymer, silica and light sensitive diazo may contain the various adjuncts usual in the manufacture of light sensitive diazotype ma terials. These include metal salts for intensification of the dyestuif image, suchas ammonium sulfate, nickel sulfate, zinc chloride and the like; stabilizing agents such as thiourea, thiosinamine, naphthalene trisulfonic acid and the like; acids acting to retard precoupling such as acetic acid,'boric acid, tartaric acid and the like; hygroscopic agents such as glycol, glycerinand the like; and wetting agents such as saponin, lauryl sulfonate, keryl benzene sulfonate, the oleic acid 'amid of N-methyl.taurine and the like.
• metal salts for intensification of the dyestuif image suchas ammonium sulfate, nickel sulf
• agents which have the property of accelerating the rate of azo dye color development. particularly under conditions of low ammonia concentration.
• thiourea derivatives and, particularly those in which either one or both nitrogen atoms are substituted byan aliphatic radi cal. Examples of such compounds are l-allyl-3-p-hydroxyethyl-Z-thiourea; 1-allyl-2-thiourea and the like.
• the ratio of silica to binder is not as critical in our procedure as in the procedure of U. S. P. 2,662,013.
• the quantity of binder may range from /6 to 1 part by weight for each part by weight of silica.
• the quantity of silica on the other hand, based on the weight of the light sensitive diazonium compound is about 1 part of the diazonium compound to 1 to 4 parts of silica.
• the base to which our coating solution is applied may be any of the bases which have been previously suggested for use in the diazotype field.
• bases are high grade all-sulfite bond paper, rayon or cotton cloth, starch filled cloth, partially hydrolyzed cellulose acetate film base, regenerated cellulose acetate and the like.
• the polyvinyl ester dispersion is essentially composed of discrete water insoluble particles of resin with tiny amounts of polyvinyl alcohol in solution. Being in the insoluble state, the concentration used raises viscosity negligibly compared to what a typical water soluble resin in an equally effective concentration would. This permits rapid sensitizing and drying during the coating operation.
• the low pH of the coating solution in combination with the heating applied during the drying step hydrolyzes a small amount of the polyvinyl ester to polyvinyl alcohol on the surface of the particles thus making these particles more receptive to impregnation by the coating solutioningredients.
• the low block temperature of the resin permits a portion of the particles to fuse during the drying step.
• This fusion together with the well-known adhesive qualities of the polyvinyl ester, makes its binding properties upon the silica especially desirable.
• this polyvinyl ester In the diazotype system in which this polyvinyl ester is used, one can thus visualize the eflfectsof coating solution and resin acting upon one another to produce in a discrete particle, discontinuous film form, a mixture of polyvinyl alcohol and polyvinyl ester, the latter being partially hydrolyzed, unhydrolyzed and partially fused.
• This mixture represents a very effective manner for receiving the coating solution and enhancing the density of the dye images formed therein.
• Example I High grade all-sulfite bond paper is coated with a sensitizing solution of the following composition:
• Example 11 High grade all-sulfite bond paper is coated with a sensitizing solution of the following composition:
• Example III A high grade, well-sized bond paper is coated with the following solution:
• Example IV The procedure is the same as in Example I, excepting that there is employed 50% solids cationic type polyvinyl chloride aqueous suspension in lieu of the polyvinyl acetate of Example I.
• Example V The procedure is the same as in Example II, except ing that there is employed, in lieu of the polyvinyl acetate, 50% solids cationic type vinyl acetateacrylic acid copolymer aqueous dispersion, the content of acrylic acid in said copolymer being 20% by weight.
• a light sensitive composition for diazo type materials comprising a compatible aqueous dispersion of a light sensitive diazonium compound, a water insoluble polymer of a vinyl ester selected from the class consisting of those which are cationic and non-ionic and finely divided silica.
• composition as defined in claim 1, wherein the water insoluble polymer is polyvinyl acetate.
• composition as defined in claim 1, wherein the silica has a particle size ranging from 1 to 5 microns.
• a water receptive base coated with a light sensitive composition comprising a compatible aqueous dispersion of a light sensitive diazonium compound, a polymer of a vinyl ester selected from the class consisting of those which are cationic and non-ionic and finely divided silica.
• silica has a particle size ranging from 1 to 5 microns.

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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)
• Photosensitive Polymer And Photoresist Processing (AREA)

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Cited By (20)

Citations (7)

• 0
  • NL NLAANVRAGE8601394,A patent/NL188976B/xx unknown
  • BE BE529755D patent/BE529755A/xx unknown
• 1954
  • 1954-02-10 US US409521A patent/US2822272A/en not_active Expired - Lifetime
  • 1954-06-22 CH CH337726D patent/CH337726A/de unknown
  • 1954-08-17 GB GB23942/54A patent/GB752422A/en not_active Expired

Patent Citations (7)

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