Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H19/00—Coated paper; Coating material
  • D21H19/36—Coatings with pigments
  • D21H19/44—Coatings with pigments characterised by the other ingredients, e.g. the binder or dispersing agent
  • D21H19/62—Macromolecular organic compounds or oligomers thereof obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/16—Nitrogen-containing compounds
  • C08K5/34—Heterocyclic compounds having nitrogen in the ring
  • C08K5/3442—Heterocyclic compounds having nitrogen in the ring having two nitrogen atoms in the ring
  • C08K5/3445—Five-membered rings
  • C08K5/3447—Five-membered rings condensed with carbocyclic rings
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/16—Nitrogen-containing compounds
  • C08K5/34—Heterocyclic compounds having nitrogen in the ring
  • C08K5/35—Heterocyclic compounds having nitrogen in the ring having also oxygen in the ring
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H19/00—Coated paper; Coating material
  • D21H19/36—Coatings with pigments
  • D21H19/44—Coatings with pigments characterised by the other ingredients, e.g. the binder or dispersing agent
  • D21H19/52—Cellulose; Derivatives thereof
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H19/00—Coated paper; Coating material
  • D21H19/36—Coatings with pigments
  • D21H19/44—Coatings with pigments characterised by the other ingredients, e.g. the binder or dispersing agent
  • D21H19/56—Macromolecular organic compounds or oligomers thereof obtained by reactions only involving carbon-to-carbon unsaturated bonds
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H19/00—Coated paper; Coating material
  • D21H19/36—Coatings with pigments
  • D21H19/44—Coatings with pigments characterised by the other ingredients, e.g. the binder or dispersing agent
  • D21H19/56—Macromolecular organic compounds or oligomers thereof obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • D21H19/60—Polyalkenylalcohols; Polyalkenylethers; Polyalkenylesters
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H21/00—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties
  • D21H21/14—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties characterised by function or properties in or on the paper
  • D21H21/30—Luminescent or fluorescent substances, e.g. for optical bleaching
• • 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
  • G03C1/76—Photosensitive materials characterised by the base or auxiliary layers
  • G03C1/815—Photosensitive materials characterised by the base or auxiliary layers characterised by means for filtering or absorbing ultraviolet light, e.g. optical bleaching
  • G03C1/8155—Organic compounds therefor

Definitions

• the present invention relates to a process for whitening the surface color of papers provided with one or more surface coatings the composing elements of which are not able to strongly bind optical bleaching agents, and more particularly relates to a process for brightening the white areas in photographic images whereby the wandering of optical bleaching agents out of the photographic layers is inhibited.
• the reflecting power of the paper surface can considerably be increased by applying a surface coating containing filling substances with a high degree of whiteness.
• filling substances are i.a. titanous dioxide, barium sulphate, zinc sulphide, calcium carbonate and silicium dioxide.
• the surface color of the paper can be whitened to a certain extent, but not completely. If, however, a paper is concerned where this surface coating contains besides the white pigments products which are slightly colored or which are colored during the further treatments or during the storage of the paper or where on this surface coating still one or more other layers are coated which contain such products, the brightening eifect obtained by applying the reflecting surface coating is nullified wholly or partially.
• the surface color of the photographic paper is not completely white so that even the whitest areas in a photographic image obtained upon such a support still absorb a considerable amount of light.
• This coloration depends on various factors such as the reflecting power of the used paper, the quality of the gelatin applied as binding agent for the photographic layers and the kind and the amount of compounds such as e.g. sensitizing dyestuffs added to the photographic layers during the manufacture of the light-sensitive element.
• This coloration can also be caused by colored decomposition products which are formed during the development and further treatments of the photographic element in the photographic layers or are absorbed by these layers from the baths wherein they were formed.
• the photographic paper Since the cellulose fibers wherefrom the paper is composed, as well as the gelatin used as binding agent for the photographic layers and the decomposition products which are formed during the processing absorb the light particularly in the range of the short wave-lengths, the photographic paper shows in most cases a slight yellow tinge.
• the incident visible light is not completely reflected but partly absorbed by the yellow paper and partly by the blue dyestuif or the blue pigment.
• the whitest areas in the photographic image will not completely reflect the visible light.
• substantially colorless blue-fiuorescing ultraviolet-absorbing compounds are added during the manufacture to the paper or to one or more surface coatings e.g. compounds absorbing ultraviolet radiation of between about 3000 Angstrom units and 4000 Angstrom units and emitting fluorescent light of between about 4000 Angstrom units and 5500 Angstrom units.
• These compounds can be added during the manufacture of a photographic paper for instance to the paper support, to the layer wherein the photographic image is formed (for instance the silver halide emulsion layer) or to a layer therebetween (for instance a baryta-coating).
• the photographic element can also be treated with a solution of such compounds during the processing.
• the spectral partition of the reflected visible light is equalized by the use of these optical bleaching agents to that of the incident visible light by conversion of a part of the incident ultra-violet rays to which the human eye is not sensitive into the blue light absorbed by the paper.
• the reflected light is now completely neutral, without loss of a part of the visible incident light.
• the great difficulty in finding an effective solution for this problem mainly results from the fact that the optical bleaching agents are not or at least insufficiently adsorbed on elements, such as gelatin and baryt-a of which the usual surface-coatings applied to the paper are composed.
• Suitable polyesters for carrying out the process according to the present invention are for instance the oligomers of aromatic polyesters which can be prepared in a simple way by re-esterifying the dimethyl ester of an aromatic acid with a lower diol in the presence of a catalyst which mainly influences the re-esterification and to a less extent the polycondensation.
• a catalyst which mainly influences the re-esterification and to a less extent the polycondensation.
• PREPARATION 1 100 g. of dimethylterephthalate, 75 cm. of ethyleneglycol (molar proportion 112.63) and 0.015 g. of zinc acetate are heated for 3 hours in such a way that the liberated methanol (about 40 cm. is slowly distilled over. When no methanol distills over anymore, temperature is raised to 180190 C. and slowly increased until about 30 cm. of glycol has distilled over. The reaction mixture is crushed after cooling and as the case may be, ground under the addition of a certain amount of Water.
• PREPARATION 2 100 g. of a mixture consisting of equal parts of isoand terephthalic acid dimethylester, 75 cm. of glycol and 0.030 g. of zinc monomethyl terephthalate are heated for 3 hours so that the liberated methanol slowly distills over. When no methanol distills over anymore, the temperature is raised to 180-l90 C. and slowly increased until 38 cm. of glycol has distilled over. After cooling, the reaction mixture is crushed and as the case may be, ground under addition of a certain amount of water.
• PREPARATION 3 50 g. of dimethylisophthalate, 50 g. of dimethyl-pcarboxyphenyl-sulphone, 60 cm. of glycol and 0.020 g. of zinc acetate are heated for 3 hours, so that the liberated methanol distills over slowly. When no methanol distills over anymore, the temperature is raised to 200 C. and maintained until about 30 cm. of glycol has distilled over. After cooling, the reaction mixture is crushed and as the case may be, ground under addition of a certain amount of water.
• a polyamide which is suitable for carrying out the method according to the present invention can be prepared as follows:
• PREPARATION 4 20 g. of caprolactam and 0.05 g. of carbonate-free sodium hydroxide are heated for about minutes at 95 C. whilst pure nitrogen is bubbled through. Thereafter, heating is continued for another minutes at 230 C. and then the reaction mixture whilst strongly stirring is poured out into 1 /2 1. of water, sucked off and thoroughly washed with warm water.
• Suitable optical bleaching agents for carrying out the process of the present invention are described i.a. in Phot. Korrespondenz, 94 (1958), p. 5.
• a certain amount of the finely divided macromolecular product is dispersed in water.
• a solution of the optical bleaching agent involved If the optical bleaching agent is not or not sufficiently soluble, it can be added in dispersed form to the suspension.
• the treatment of the macromolecular product with the optical bleaching agent is preferably carried out at a temperature between and 100 C. and is continued until no more fluorescing substance is bound. After sucking off, a strongly fluorescing paste is thus obtained which strongly retains the fluorescing substance and v which can be added to the coating composition which is to be applied to a paper support.
• the fluorescing mass can for instance be added to a baryta-composition which is spread upon a paper whereon a photographic emulsion is to be coated.
• the fluorescing paste can, as the case may be, be incorporated in a photographic emulsion itself, in which case very favorable results can be attained by using as macromolecular product an ureaformaldehyde resin such as described in the Belgian specification 451,470 and which i.a. also compreses condensation products with a characteristically low degree of polymerization.
• the wandering of the optical bleaching agent out of the layer, wherein it was applied, is practically completely excluded by applying the method according to the present invention, so that the exposed photographic element after complete processing, which even may comprise a protracted rinsing, yields a photographic image wherein the white areas are strongly brightened.
• the method according to the present invention can be applied for brightening the white areas in usual photographic black-and-White and colored images as well as for whitening the surface color of any other surfacecoated paper such as for instance papers on which a positive photographic image is formed by applying the silver halide diffusion transfer process, or papers on Which an image is printed by means of an hectographic process.
• Example I 1 kg. of the polyester paste, obtained according to Preparation 1 is dispersed in 1500 cm. of a 5% aqueous solution of sodium sulphate together with 10 g. of a,,8-
• the whole mass is kept in suspension for 30 minutes at a temperature of 80-90 C.
• this treatment the fluorescing mass is sucked off and the strongly fluorescing paste thus obtained is added to a baryta composition which is spread on a paper to be coated with one or more photographic emulsion layers.
• the whiteness of the surface color of the photographic paper thus treated is not lost on rinsing and the photographic element yields after exposure and complete finishing a photographic image wherein the white areas are quinoline (cf. Formula 2), or a,,8-di-(benzimidaZyl-2)- ethylene (cf. Formula 11).
• Example 2 1 kg. of the polyester paste obtained according to Preparation 2 is dispersed in 1500 cm. of water together with g. of a,B-di(5-methylbenzimidazyl-2)ethylene (cf. Formula 1). By strongly stirring, the whole mass is kept in suspension for 30 minutes at a temperature of 60 C. After this treatment, the fluorescing mass is sucked off and the strongly fluorescing paste thus obtained is added to a baryta composition which is spread on a paper. The surface color is clearly white and is not modified when the paper is rinsed with water for a longer time.
• Example 3 1 kg. of the polyester paste obtained according to preparation 3 is dispersed in 1500 cm. of a 5% aqueous solution of sodium sulphate together with 10 g. of a,B-di(5- methylbenzimidazyl-Z)-ethylene (of. Formula 1). By strongly stirring, the whole mass is kept in suspension for 30 minutes at a temperature of 90 C. After this treatment the fiuorescing mass is sucked off and treated as indicated in Example 1.
• Example 4 1 kg. of the polyamide paste obtained according to the Preparation 4 is suspended in 1500 cm. of a 5% aqueous solution of sodium sulphate together with 10 g. of 4,4- bis(2 hydroxy 4-phenylamino-1,3,5-triazyl-6)-diaminostilbene-2,2-disulphonic acid disodium salt (cf. Formula 3). By strongly stirring the whole mass is kept in suspension for 30 minutes at a temperature of 8090 C. After this treatment the fluorescing mass is sucked Off and treated as indicated in Example 1.
• Example 5 1 kg. ground cellulose is dispersed in 1000 cm. of water. To this suspension are added 400 cm. of a 1% aqueous solution of the compound 4,4-bis(2-hydroxy-4-phenylamino 1,3,5 triazyl 6)-diaminostilbene-2,2-disulphonic acid disodium salt (cf. Formula 3). By strongly stirring, the whole mass is kept in suspension at a temperature of 50100 C. until no more fluorescing substance is bound by the cellulose. After this treatment the fluorescing mass is sucked off and the thus obtained strongly fluorescing paste is added to a baryta composition which is spread upon a paper whereon one or more photographic silver halide emulsion layers are to be coated. The whiteness of the surface color of the photographic paper thus treated is not lost on rinsing and the photographic element yields after exposure and complete finishing a photographic image wherein the light parts are strongly brightened.
• Example 7 1 kg. of ground cellulose is dispersed in 1000 cm. of water, together with 10 g. of a,,8-di(S-methylbenzimidazyl- 2)-ethylene (cf. Formula 1). By strongly stirring the whole mass is kept in suspension for 30 minutes at a temperature of 50100 C. After this treatment the fiuorescing mass is sucked off and further treated as given in Example 2.
• Example 8 1 kg. of an ureaformaldehyde resin, prepared according to the method indicated in Example 1 or 2 of the Belgian specification 451,470 is dispersed in 3000 cm. of water together with 10 g. of a,,B-di(5-methylbenz imidiaZyl-2)-ethylene (cf. Formula 1). By strongly stirring, the whole mass is kept in suspension for 30 minutes at a temperature of 5070 C. After this treatment, the fluorescing mass is sucked off. 50 g. of the strongly fluorescing paste thus obtained are added to 1 kg. of a photographic silver halide emulsion coated on a paper support. The whiteness of the surface color of the photographic paper thus obtained is not lost on rinsing and the photographic element yields after exposure and complete finishing a photographic image wherein the white areas are strongly brightened.
• Example 9 1 kg. of an ureaformaldehyde resin prepared according to the method indicated in Example 1 or 2 of the Belgian specification 451,470 is suspended in 3000 cm. of water. To this suspension are added 1000 cm. of a 1% ethanol solution of the compound 4,5-diphenylimidazolone-Z (cf. Formula 10). By strongly stirring, the whole mass is kept in suspension for 30 minutes at a temperature of 50-70 C. After this treatment, the fluorescing mass is sucked oif and further treated as indicated in Example 8.
• Light-sensitive photographic paper comprising a I H paper base, a white pigmented coating and a light-sensig tive silver halide emulsion layer, said White pigmented 0 coating containing a fluorescent mass comprising a mem- HaC(CH1)a z)a1 IH 2 her selected from the group consisting of a,,6-di(5-methyl- (7) OH CH N r 3 H C(l]OH (0-OII2-OH2)2-CHzNH-(] (flJ-NH- OH:

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Health & Medical Sciences (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
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Cited By (10)

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Citations (3)

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• 0
  • BE BE568156D patent/BE568156A/xx unknown
• 1957
  • 1957-06-06 NL NL217900A patent/NL92774C/xx active
• 1958
  • 1958-06-02 US US739211A patent/US3047390A/en not_active Expired - Lifetime
  • 1958-06-05 FR FR767201A patent/FR1239314A/fr not_active Expired
  • 1958-06-06 DE DEG24704A patent/DE1108560B/de active Pending
  • 1958-06-06 GB GB18194/58A patent/GB884736A/en not_active Expired
• 1960
  • 1960-03-12 DE DEG29220A patent/DE1149244B/de active Pending
  • 1960-03-12 FR FR821173A patent/FR77342E/fr not_active Expired
• 1962
  • 1962-06-11 US US201300A patent/US3181950A/en not_active Expired - Lifetime

Patent Citations (3)

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