EP0439944A2 - Papier photothermographique pour enregistrement recto-verso - Google Patents

Papier photothermographique pour enregistrement recto-verso Download PDF

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Publication number
EP0439944A2
EP0439944A2 EP90313868A EP90313868A EP0439944A2 EP 0439944 A2 EP0439944 A2 EP 0439944A2 EP 90313868 A EP90313868 A EP 90313868A EP 90313868 A EP90313868 A EP 90313868A EP 0439944 A2 EP0439944 A2 EP 0439944A2
Authority
EP
European Patent Office
Prior art keywords
silver
layer
weight
polyvinyl acetate
coating
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.)
Withdrawn
Application number
EP90313868A
Other languages
German (de)
English (en)
Other versions
EP0439944A3 (en
Inventor
Gregory J. C/O Minnesota Mining And Mccarney
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 EP0439944A2 publication Critical patent/EP0439944A2/fr
Publication of EP0439944A3 publication Critical patent/EP0439944A3/en
Withdrawn legal-status Critical Current

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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
    • G03C1/494—Silver salt compositions other than silver halide emulsions; Photothermographic systems ; Thermographic systems using noble metal compounds
    • G03C1/498—Photothermographic systems, e.g. dry silver
    • G03C1/49836—Additives
    • G03C1/49863—Inert additives, e.g. surfactants, binders

Definitions

  • the present invention relates to dry silver photothermographic imaging elements and in particular to dry silver photothermographic imaging elements comprising an opaque substrate having imageable photothermographic layers on both sides of the substrate.
  • Silver halide photothermographic imaging materials often referred to as "dry silver" compositions because no liquid development is necessary to produce the final image, have been known in the art for many years. These imaging materials basically comprise a light insensitive, reducible silver source, a light sensitive material which generates silver when irradiated, and a reducing agent for the silver source.
  • the light sensitive material is generally photographic silver halide which must be in catalytic proximity to the light insensitive silver source. Catalytic proximity is an intimate physical association of these two materials so that when silver specks or nuclei are generated by the irradiation or light exposure of the photographic silver halide, those nuclei are able to catalyze the reduction of the silver source by the reducing agent.
  • silver is a catalyst for the reduction of silver ions and the silver-generating light sensitive silver halide catalyst progenitor may be placed into catalytic proximity with the silver source in a number of different fashions, such as partial metathesis of the silver source with a halogen-containing source (e.g., U.S. Pat. No. 3,457,075), coprecipitation of the silver halide and silver source material (e.g., U.S. Pat. No. 3,839,049), and any other method which intimately associates the silver halide and the silver source.
  • a halogen-containing source e.g., U.S. Pat. No. 3,457,075
  • coprecipitation of the silver halide and silver source material e.g., U.S. Pat. No. 3,839,049
  • the silver source used in this area of technology is a material which contains silver ions.
  • the earliest and still preferred source comprises silver salts of long chain carboxylic acids, usually of from 10 to 30 carbon atoms.
  • the silver salt of behenic acid or mixtures of acids of like molecular weight have been primarily used. Salts of other organic acids or other organic materials such as silver imidazolates have been proposed, and U.S. Pat. No. 4,260,677 discloses the use of complexes of inorganic or organic silver salts as image source materials.
  • the latent image In both photographic and photothermographic emulsions, exposure of the silver halide to light produces small clusters of silver atoms. The imagewise distribution of these clusters is known in the art as the latent image. This latent image generally is not visible by ordinary means and the light sensitive article must be further processed in order to produce a visual image. The visual image is produced by the catalytic reduction of silver ions which are in catalytic proximity to the specks of the latent image.
  • Useful resins such as poly(vinyl butyral), cellulose acetate butyrate, polymethyl methacrylate, ethyl cellulose, polystyrene, polyvinyl chloride, chlorinated rubber, butadiene-styrene copolymers, vinyl chloride-vinyl acetate copolymers; copolymers of vinyl acetate, vinyl chloride, and maleic acid and poly(vinyl alcohol) were cited.
  • U.S. Patent No. 4,460,681 discloses a color photothermographic element in which color forming layers are separated by barrier layers to prevent migration of components between layers which would reduce the color separation.
  • the imageable article of the present invention comprises a substrate having on both sides thereof at least one dry silver photothermographic emulsion layer in which the binder for the emulsion layer comprises above 2.0% and usually at least 2.5% by weight of polyvinyl acetate.
  • Conventional photothermographic chemistry is usually constructed as one or two layers on the same side of a substrate.
  • Single layer constructions must contain the silver source material, the silver halide, the developer and binder as well as optional additional materials such as toners, coating aids and other adjuvants.
  • Two-layer constructions on the same side of a substrate must contain silver source and silver halide in one emulsion layer (usually the layer adjacent substrate) and the other ingredients in the second layer or both layers.
  • the silver source material ordinarily may be any material which contains a reducible source of silver ions.
  • Silver salts of organic acids, particularly long chain (10 to 30, preferably 15 to 28 carbon atoms) fatty carboxylic acids are preferred in the practice of the present invention.
  • Complexes of organic or inorganic silver salts wherein the ligand has a gross stability constant between 4.0 and 10.0 are also useful in the present invention.
  • the silver source material should constitute from about 20 to 70 percent by weight of the imaging particles. Preferably it is present as 30 to 55 percent by weight.
  • the silver halide may be any photosensitive silver halide such as silver bromide, silver iodide, silver chloride, silver bromoiodide, silver chlorobromoiodide, silver chlorobromide, etc., and may be added to the article in any fashion which places it in catalytic proximity to the silver source.
  • the silver halide is generally present as 0.75 to 15 percent by weight of the layer, although larger amounts are useful. It is preferred to use from 1 to 10 percent by weight silver halide in the particle and most preferred to use from 1.5 to 7.0 percent.
  • the silver halide may be provided by in situ halidization or by the use of pre-formed silver halide.
  • sensitizing dyes for the silver halide is particularly desirable. These dyes can be used to match the spectral response of the emulsions to the spectral emissions of intensifier screens. It is particularly useful to use J-banding dyes to sensitive the emulsion as disclosed in U.S. Patent No. 4,476,220.
  • the reducing agent for silver ion may be any material, preferably organic material, which will reduce silver ion to metallic silver.
  • Conventional photographic developers such as phenidone, hydroquinones, and catechol are useful, but hindered phenol reducing agents are preferred.
  • the reducing agent should be present as 1 to 20 percent by weight of the imaging layer. In a two-layer construction, if the reducing agent is in the second layer, slightly higher proportions, of from about 2 to 20 percent tend to be more desirable.
  • Toners such as phthalazinone, phthalazine and phthalic acid are not essential to the construction, but are highly desirable. These materials may be present, for example, in amounts of from 0.2 to 5 percent by weight.
  • the binder may be selected from any of the wellknown natural and synthetic resins such as gelatin, polyvinyl acetals, polyvinyl chloride, cellulose acetate, polyolefins, polyesters, polystyrene, polyacrylonitrile, polycarbonates, and the like. Copolymers and terpolymers are, of course, included in these definitions.
  • the polyvinyl acetals, such as polyvinyl butyral and polyvinyl formal, and vinyl copolymers, such as polyvinyl acetate/chloride are particularly desirable.
  • the binders are generally used in a range of from 20 to 75 percent by weight of the particle, and preferably about 30 to 55 percent by weight.
  • the binder for the photothermographic layer coated onto the paper substrate as the second coated photothermographic system must contain above 2.0% and usually at least 2.5% or preferably at least 3% by weight of total solids in the dry layer as polyvinyl acetate (PVAc).
  • the polyvinyl acetate may be present as a homopolymer or copolymer. If present as a copolymer, the PVAc units should comprise at least 2.5% or 3% by weight of the total solids in the imaging layers of the system (not just the copolymer unless only the copolymer is used) as the binder. It is preferred to use polymeric additives having at least 5% or at least 10% by weight of total solids as PVAc. It is sometimes desirable to use at least 50% by weight units of PVAc or even 100% and most preferable to use PVAc homopolymers as the additive.
  • toners, accelerators, acutance dyes, sensitizers, stabilizers, surfactants, lubricants, coating aids, antifoggants, leuco dyes, chelating agents, binder crosslinking agents, and various other well-known additives may be usefully incorporated in either the particle or continuous layer.
  • acutance dyes matched to the spectral emission of an intensifying screen is particularly desirable.
  • a particularly useful chemistry which can be present in the layer binder is stabilization chemistry, and particularly image stabilization chemistry.
  • Crosslinking agents either active or thermally latent, for the particle binder or the binder in the photosensitive layer can be present in the layer binder.
  • Other standard addenda such as coating aids, antifoggants, accelerators, toners, and acutance dyes may be present in the layer binder.
  • the effect of the polyvinylacetate polymer is believed to be that of a moderator of the vapor transmission of the coated layers, thus avoiding the defect produced by escaping vaporized gases blistering and otherwise deforming the plastic film that is formed on the substrate.
  • the observed defect is not due to poor wetting of the substrate by the coating media, as coatings applied with and without PVAc resin wet the paper and form a continuous film upon it with apparent equal ability.
  • the blister defects are observed to occur as the wet film is dried down to its solid components and the solvents are released.
  • the PVAc may be present as homopolymers, copolymers, graft copolymers, block copolymers, and the like. High levels of ethylene or polyvinylchloride in the polymer would not be desirable as that should have the effect of decreasing the permeability of the PVAc.
  • acetone/AYAF solutions were combined in a vial and added to each sample batch with agitation.
  • the respective amounts of AYAF PVAc polymeric resin added to the five 100 gram samples of the silver dispersion were 0, .25, .5, 1.0, and 2.0 grams (in Samples A, B, C, D, and E, respectively). These levels equate to (respectively) 0, 1.2, 2.4, 4.7, and 9.4% polyvinylacetate relative to the total dry solids left in the coating after the solvents have been removed by the drying process.
  • the five finished dispersions were then coated on the uncoated side of the aforementioned paper base.
  • the wet coating thickness was metered with a knife coating head set at 4.0 mils (102 microns).
  • the coatings were transported into a 'Blue M' oven on a moving web and dried at 77°C. for 2.5 minutes.
  • the evaluation of the sample coatings is noted below:
  • Victoria Pure Blue dye was added as a colorant to make detection of the blister defects easier in the white unprocessed sheet samples.
  • the above dispersion was coated on side two of a base paper (Simpson SP 7772 39# paper) which had been previously coated on side one with the silver soap dispersion noted in Example 1.
  • the silver dispersion was split into 100 gram portions to which were added various polyvinylacetate polymers or copolymers. The listing of those samples appears below:
  • the finalized dispersions were coated at 4.0 mils (102 microns) with a notched bar coater and dried for 2 minutes at 77°C in a modified Blue M oven. The dried coatings were evaluated for blister type defects and were compared with the control sample. The evaluations of the samples are shown below.
  • Polyvinylacetate polymers are also found to improve the coating uniformity of other coated layers cast from solutions for two sided photothermographic constructions. For instance, it is common to overcoat the silver image forming layer with a protective topcoat, which may also contain elements of the activating chemistry for the total construction. These topcoats also suffer defects of blisters and open coat voids when applied to a two-sided sheet construction in which both sides have already been coated with the silver imaging layer.
  • the use of polyvinylacetate resins as a coating aid in such two sided constructions is again found to improve coating uniformity, to the point of eliminating such defects.
  • This overcoat was applied over the silver imaging layer of a previously coated two-sided construction in which the silver layers had been applied to each side of a paper base (SP 7774 60# paper, Simpson Paper Co.) and dried to form continuous, defect free coatings on each side.
  • the silver imaging media was similar to that described in Example 1, with 1.5% by weight AYAF polyvinylacetate resin (Union Carbide Co.) To 100 gram portions of the above premix, the following resins were added and dissolved with a mechanical shaker prior to coating of the overcoat:
  • overcoat formulations were coated at 3.4 mils (85 microns) wet orifice on a notched bar coater and dried for 1.5 minutes at 77°C.
  • the coated samples were evaluated for freedom from coating defects that would normally be encountered when coating this solvent-based formulation over a paper substrate having both sides already coated with the thermoplastic silver imaging layers. To provide maximum visibility of the defects, the samples were exposed to a light source (Olix AI 121 ultraviolet printer with Kokomo filter, 8 second exposure) and thermally developed (3M Model 9014, six seconds processing at 132°C). The evaluations of those samples appear below.
  • Example 2 The experimental series of polyvinylacetate levels described in Example 1 was later repeated on a different paper substrate.
  • a 60# base sheet made by Simpson Paper Co. was tested.
  • This second sheet was identified as "SP 7773" paper, and differed from SP 7772 in several aspects: SP 7773 was not opacified with titanium dioxide, it was manufactured with a high solids latex size press coating, it utilized an aluminum chloride (rather than aluminum sulfate) flocculating agent, and it was greater in caliper (as expected, given its higher basis weight).
  • the procedure for the silver dispersion batch preparation was identical to that listed in Example 1, except that the mixing time after the addition of mercuric chloride was only twenty minutes.
  • AYAF was accompanied by compensating weight addition of acetone, as listed in Example 1.
  • the levels of AYAF resin added to Samples A, B, C, D, and E were respectively 0, .25, .5, 1.0, and 2.0 grams per 100 grams of silver imaging media, as was the case in Example 1.
  • Example 2 The coating conditions were the same as indicated in Example 1, with the finished silver dispersion coated on each side of the SP 7773 base.
  • the resulting coating uniformity with the five levels of AYAF addition are listed below.
  • Examples 1 and 4 establish .5 grams of AYAF added to 100 grams of the silver dispersion as a threshold for effective reduction of blistering during coating and drying of the silver imaging layer. This equates to a percentage of about 2.4%, based on the solid components of the dried coating media. The minimum effective level is expected to be additionally affected, however, by drying conditions, applied media coating weights, and by solvent holdout, density, and water content of the substrate.

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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)
EP19900313868 1990-01-31 1990-12-19 Two-side imageable photothermographic paper Withdrawn EP0439944A3 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US47277790A 1990-01-31 1990-01-31
US472777 1990-01-31

Publications (2)

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EP0439944A2 true EP0439944A2 (fr) 1991-08-07
EP0439944A3 EP0439944A3 (en) 1991-08-28

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EP19900313868 Withdrawn EP0439944A3 (en) 1990-01-31 1990-12-19 Two-side imageable photothermographic paper

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EP (1) EP0439944A3 (fr)
JP (1) JPH05197066A (fr)
CA (1) CA2029980A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1996015478A3 (fr) * 1994-11-16 1996-06-20 Minnesota Mining & Mfg Element photothermographique a adherence entre couches amelioree
WO1997004355A1 (fr) * 1995-07-18 1997-02-06 Agfa-Gevaert Naamloze Vennootschap Materiau d'enregistrement photo-thermographique revetu a partir d'un milieu aqueux
EP0889355A1 (fr) * 1997-07-04 1999-01-07 Agfa-Gevaert N.V. Matériau (photo)thermographique avec un fond bleu

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6146821A (en) 1997-07-04 2000-11-14 Agfa-Gevaert (Photo) thermographic material with a blue background
DE60011390T2 (de) 1999-01-28 2004-10-14 Université De Genève Verfahren und vorrichtung zur identifikation oder karakterisierung von polypeptiden

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3672933A (en) * 1970-11-30 1972-06-27 Du Pont Preparation of photosensitive coated papers by single pass per side

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1996015478A3 (fr) * 1994-11-16 1996-06-20 Minnesota Mining & Mfg Element photothermographique a adherence entre couches amelioree
WO1997004355A1 (fr) * 1995-07-18 1997-02-06 Agfa-Gevaert Naamloze Vennootschap Materiau d'enregistrement photo-thermographique revetu a partir d'un milieu aqueux
US6143481A (en) * 1995-07-18 2000-11-07 Agfa-Gevaert Photothermographic recording material coated from an aqueous medium
EP0889355A1 (fr) * 1997-07-04 1999-01-07 Agfa-Gevaert N.V. Matériau (photo)thermographique avec un fond bleu

Also Published As

Publication number Publication date
JPH05197066A (ja) 1993-08-06
EP0439944A3 (en) 1991-08-28
CA2029980A1 (fr) 1991-08-01

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