DE2321328A1 - IMPROVED RECORDING MATERIAL - Google Patents

Description

Improved recording material

The invention relates to recording material for the production of copies by dry means and the use of such Materials in thermal imaging processes and photographic processes.,

Thermal recording processes and photographic processes which produce copies of an original by dry means are known per se. These are essentially materials that contain light-sensitive or heat-sensitive layers. These layers are exposed or heated imagewise, as a result of which a coloring reaction is triggered which leads to the formation of the image _{or the like}

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Heat-sensitive covers that change their color through a thermally initiated reduction of a compound with an organic reducing agent change are from the British Patent specification 318 203, German patent specification 888 045 and US patents 2,129,242, 2,504,593, 2,663,654, 2,663,657 and 2,910,377 known

In the process described in German Patent 1300-014 copying method recording materials are used, an oxidizing agent, a reducing agent and a minor amount of a photosensitive compound containing "At the exposed areas formed during subsequent heating by a redox reaction, a colored BIId ₀ Suitable oxidizing agents are are organic silver salts and reducing agent aminophenols, hydroxylamines, pyrazolidones or phenols, further phenylenediamine or etherified naphthols, for _o example, 4-methoxy-naphthol-1, used "as photosensitive compounds are suitable heavy metal salts which form upon exposure to traces of the free metal; In particular, they are light-sensitive silver salts, ZoBo silver halide, which photolytically form silver on exposure. The redox reaction is initiated by these photolytically formed heavy metal nuclei.

The use of light-insensitive silver salts as oxidizing agents, e.g. silver saccharide, or silver salts of long-chain fatty acids is essential for the practical use of such materials Compound, Z ₀ B ₀ according to the method described in US Patent 3 457 075, generated

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These materials have a sensitivity in the short-wave part of the spectrum corresponding to their intrinsic sensitivity of the silver halides used and can by adding. spectral sensitizing dyes also for longer wavelengths To be sensitized to light »

In the heat-sensitive and light-sensitive layers containing silver salts, the amount of reducing agent present must be kept to a minimum in order to avoid undesired darkening of the casting solution or the layer, ie a reduction of the organic silver salts during the production and storage of the material the above-mentioned method preferably contain weak reducing agent of the type of o-alkyl-substituted phenols or hydroxycoumarans and hydroxychromans, such as are described in German Offenlegungsschriften 1908761 and 2031748 or German Patent 1,250,842, for example, ₀ c

In addition to the unsatisfactory stability of the known materials during production and storage, a further disadvantage is that, due to the yellowing of the reducing agents which remain in the layer after production, discoloration of the image background, ie _, the image whites, can be observed. In the case of some of the known reducing agents, this is so strong that a yellow or brownish spotty background arises even after a short storage period.

The invention is based on the object of finding reducing agents for the methods described above, which the Stability of the material during manufacture or storage does not deteriorate and the whiteness of the finished product does not deteriorate Do not affect the image.

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A recording material has now been found for the production of copies by dry means with a layer which contains essentially light-insensitive, reducible silver salts,
Reducing agent and optionally a toner and optionally a light-sensitive heavy metal compound,
which is optionally spectrally sensitized with a polymethine sensitizer, a bisphenol being contained as a reducing agent.
Bisphenols of the following formula are particularly suitable:

where mean:

R ^ = straight-chain or branched alkyl with preferably up to 5 carbon atoms or cycloalkyl with 5-8 carbon atoms, preferably cyclopentyl or cyclohexyl;

Rp = straight-chain or branched alkyl with preferably

up to 5 carbon atoms, cycloalkyl, in particular cyclopentyl or cyclohexyl, aralkyl such as benzyl or phenyl;
Hydrogen, alkyl with preferably up to 3 carbon atoms or cycloalkyl, preferably cyclopentyl or cyclohexyl, and
-S- or R,
-C-

where R, or R ₅ = hydrogen or alkyl, preferably with up to 3 carbon atoms, are ₀

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The bisphenols of the following formulas are particularly suitable;

C (CH,), C (CH ₃ ),

OH

—CH

CH

OH

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OH

OH

H.

OH CHo OH I. - CH ₃ H ₃ C Ί

OH OH

10)

OH

OH

C (CH ₃ ) ₃

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The bisphenols to be used in the manner according to the invention are prepared by processes known per se, Z ₀ B ₀ by reacting suitably substituted phenols with aliphatic aldehydes or sulfur dichloride can be obtained in an analogous manner ₀

Connection 3

97.6 g of 2,5 ~ di-cyclopentyl-4-methyl-phenol in 300 ml of benzene with 12.8 ml of sulfur for 3 hours at 50 ⁰ C gerührtο The solvent is evaporated and the residue recrystallized from ligroin.
Yield: 21.9 g; Mp: 194-195 ° C.

Connection 8

390 g of 3,6-dicyclopentyl-4-methylphenol 2400 ml of H ₂ O

5 ml 10 % ± ge aqueous mersolate solution

24 ml cone HCl

120 ml of 30% aqueous formaldehyde solution are stirred well at 90 - 95 ° C for 4 hours one again

160 ml of 30% aqueous formaldehyde solution 40 ml cone HCl and

Add 40 ml of 10% aqueous Mersolate solution and stir for a further 3 hours at 90-95 ° C. After cooling, the solid precipitate is filtered off with suction, dried and recrystallized from ligroin _{or the like}

Yield: 224 g; Mp 137-139 ⁰ C

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The inventive recording materials containing bisphenols are used for the processes described above Used to produce silver images by dry means

The first method uses a thermographic material having a layer that is insensitive to light Silver salt and a bisphenol as reducing agent, optionally in combination with other known reducing agents to reduce the silver salt at the heated areas contain an analogous process and similar materials are described in U.S. Patent 2,910,377

The second method uses a photographic material having a layer that is insensitive to light Silver salt and generally small amounts of a light-sensitive heavy metal salt, especially a silver salt, and bisphenol as a reducing agent, possibly in combination with other known reducing agents, to reduce the silver salts in the exposed areas One such method is described in U.S. Patents 3,457,075 and 3,589,903.

The addition of the bisphenol derivatives increases the image density and the contrast without causing a disruptive yellow haze arises in the image whites.

The amount of bisphenols added can vary within wide limits. The optimum amount depends on the desired effect, and the layer composition from _o The optimum amount can easily by a few festgestellt.werden the average skilled worker attempts _o The bisphenols can be present in concentrations from 0.1 to 2 moles, preferably 0.3 to 1 , 5 moles of reducing agent per mole of oxidizing agent, ie ₀ per mole of light-insensitive organic silver salt can be used.

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The bisphenols can also be used in a mixture with other known ones Reducing agents are applied »The concentration of the additional reducing agents can also be used within further limits fluctuate.

For example, the bisphenols mentioned can be used in combination with known organic reducing agents which contain active hydrogen bonded via 0, N or C, Z ₀ B ₀ with o-alkyl- or cycloalkyl-substituted phenols, di- and tri-hydroxyaryl, Aminophenol, aminonaphthol, p-phenylenediamine and hydroxylamine derivatives, gallates, alkoxynaphthols, acetoacetonitriles, pyrazolidin-3-one and pyrazolin-5-one, indanedione-1,3 derivatives, hydroxytetronic acids, hydroxytetronimides, reductones, Z ₀ B ₀ anhydrodihydro-pyrrolidinohexose reductone, ascorbic acid and hydroxychroman or hydroxycoumaran derivatives, for example in accordance with German Offenlegungsschrift 2,031,748; preferred are Z ₀ B ₀ o-alkyl-substituted phenols, hydroquinone, aminophenol and methoxynaphthol derivatives, bis-β-naphthols, hydroxycoumarans and hydroxychromans "

The bisphenol derivatives in the presence of the above-mentioned reducers, preferably in admixture with the sterically hindered 2,6-dialkyl such as 2,6-di-Terto-butyl and / or 2,6-Dicycloalkylwie 2,6-Dicyclohexylmonophenol applied ₀ Examples of suitable sterically hindered monophenols are described in US Pat. Nos. 3,218,166 and 3,653,907, Z ₀ B ₀ 2,6-di-tert-butyl-4-methylphenol and ₀ 2,6-dicyclohexylp-cresol _{0, respectively}

The reducing agents to be used in the manner according to the invention are preferably used in heat-sensitive copying materials in which silver salts of aliphatic carboxylic acids with a thioather group or silver salts of long-chain fatty acids with at least 14 carbon atoms such as silver behenate, Silver palmitate, silver stearate are present.

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Silver behenate and silver stearate, together with free Behenic acid or stearic acid increase the moisture resistance of the copy layer, are preferred » Other typical silver salts suitable as oxidizing agents are, for example, silver benzoate, silver phthalazinone, Silver benzotriazole, silver saccharin, silver-4'-n-octadecyloxydiphenyl-4 ~ carboxylic acid, Silver o-amlnobenzoate, silver acetate amido benzoate, Silver furoate, silver camphorate, silver p-phenylbenzoate, Silver phenyl acetate, silver salicylate, silver butyrate, Silver terephthalate, silver phthalate, silver acetate and silver hydrogen phthalato

In the variant of the material according to the invention, where light-sensitive compounds, in particular light-sensitive silver salts, are present in addition to the light-insensitive silver salts, these layers can be optically sensitized by adding dyes. As sensitizers preferably compounds are suitable which are also commonly used for optical sensitization of conventional silver halide d _o h _o cyanine dyes, merocyanines, Oxonols or rhodacyanines of various kinds, as for example ₀ in the book of F ₀ M ₀ HAMER "The Cyanine Dyes and Related Compounds "(1964) are described.

The light-sensitive heavy metal salts which are suitable for said second procedure and form upon exposure metal nuclei, which are able to initiate the image-forming redox reaction, z "B _u inorganic are or organic salts of silver, mercury or gold geeignetρ Preferred are Heavy metals of subgroup Ib of the Periodic Table of the Elements, in particular silver salts and of these in turn preferably silver halides.

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The light-sensitive heavy metal salt that is particularly suitable for the respective redox system can be determined by a few manual experiments. Thus, one can Z ₀ B ₀ mix the metal salt in the form of its aqueous suspension with the · components of the redox reaction must be carried out in the dark with no change _o this mixture is irradiated with UV, it is to be discolored relatively quickly. If these conditions apply, then the heavy metal salt is suitable for the redox system »

The photosensitive heavy metal salt is in relatively low Quantities of about 0.1-10% by weight, preferably 0.2-1 % By weight, based on the weight of the oxidizing agent, used This proportion of photosensitive salt is sufficient for most systems. In exceptional cases, this percentage can of course be exceeded or fallen short of.

The light-sensitive heavy metal salt, Z ₀ B ₀ the silver halide, should be present in such amounts that the photolytically formed heavy metal nuclei can initiate the redox reaction; however, the concentration of the silver halide should be so low that no or only negligible discoloration of the copying material occurred due to the metal nuclei formed

The silver halide can be added to the casting solution for the layer containing the components for the redox reaction or in the casting solution in situ, ie _o by precipitation of the silver halide in the mixture Silver salt originate o

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The silver halides can be prepared from the non-light-sensitive silver salts in various ways. Z ₀ B ₀ can treat the surface of the non-light-sensitive silver salts with vapors of hydrohalic acids, Z ₀ B ₀ hydrochloric acid, hydrobromic acid or hydriodic acid. The amount of silver halide formed on the surface can be kept within the desired limits by the concentration of the hydrogen halide in the vapor phase and the treatment time.

Of course, the non-photosensitive silver salts can the organic acids can also be treated with a solution containing halogen ions such as chlorine ions, bromine ions or iodine ions The halogen ions can be obtained from the hydrohalic acids themselves or their salts, in particular ammonium and alkali salts, come from »

The non-light-sensitive silver salts are preferably reacted with the halogen ion-releasing compounds in the form of their suspension in a volatile, non-aqueous liquid. However, it is also possible to react the dry salts Z ₀ B ₀ with hydrogen halide vapors. In addition to hydrogen halide acids and salts thereof, Z ₀ B ₀ the above-mentioned alkali metal salts, ammonium salts, alkaline earth metal salts or other metal salts, such as zinc salts, and mercury salts can also ionizable organic halogen compounds are used, for example, _o triphenylmethyl bromide, 2-bromo-2-methylpropane, 2-bromobutyric acid, , 2-bromoethanol or benzophenone dichloride «

The formation of the light-sensitive silver halides from the light-insensitive silver salts of the organic acids is preferred for the production of this modification »The ability of the silver halides to be photolytic To form silver nuclei, which are particularly effective for introducing

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The redox reaction is favored by “Separate production the silver halides and later mixing with the light-insensitive silver salts also lead to usable ones However, materials which have photolytic heavy metal nuclei formed from such mixtures are generally not so effective.

Some of the useful in the present invention, light-insensitive per se silver salts exhibit in precipitation in the presence of a protective colloid, Z ₀ B ₀ proteins, particularly gelatin, as usually proceed in the production of conventional Silberhalogenidgelatineemulsionen, some - albeit small - intrinsic sensitivity _o In the Precipitation of the silver salts for the production of the material according to the invention must therefore be carried out in such a way that the silver salts formed are insensitive to light. This is generally already achieved if precipitation is carried out in the absence of a protective colloid "

The dried silver salts are then added to the solutions or dispersions of the desired layer binder. The concentration of the silver salt in the binder dispersions can vary within wide limits, depending on the situation desired silver application in the photographic layers " In general, amounts of 0.01-0.1 moles of silver salt are per Kilogram of casting solution sufficient »Preferably, 0.02-0.05 mol of silver salt is used per kilogram of the solution or Dispersion »The same applies to the application of silver in the finished photographic layer “Here, too, the concentration can be varied within wide limits depending on the desired effect and the intended use, in general the order is 0.1 - 1.5 g of silver in the form of the silver

2 ?

salt per m, preferably 0.2-1 g per m ~.

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Of course, mixtures of different light-insensitive 'silver compounds are used in the context of the material according to the invention.

To improve the photographic properties of the material according to the invention, other light-insensitive heavy metal compounds can be added to the material, preferably to the layer containing the light-insensitive silver salt. In this way one can, for example, _o a reduction of the veil, an increase in the density or a shift in the image tone to desired shades, z-.B "neutral black to achieve.

Bind suitable for this purpose, for example, salts or _o compounds of mercury, cadmium, lead, uranium, gold, platinum? Palladium or Rhodiumo The heavy metal compounds can be added during the precipitation of the silver salt. Preferably, solutions of the heavy metal salts and the silver salts are added to the submitted precipitation component in the double inlet process and are precipitated at the same time. Although the joint precipitation of the silver salt and the heavy metal salt is particularly advantageous and, depending on the nature of the heavy metal salt, produces particularly favorable effects, the heavy metal salts can, however, also be added in solid or dissolved form to the casting solutions already containing silver salt for the photographic layer. The heavy metal salts can also be mixed with the dried silver salts by grinding or added shortly before the casting solution for the photographic layer is poured _o Of course, combinations of different heavy metal salts can also be used "

The amount of heavy metal salts or heavy metal compounds added can vary within wide limits. Here, too, the concentration depends on the type of difficulty

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metal salt and silver salt and the desired effect. The optimal amount can easily be determined by any average person skilled in the art with a few simple manual experiments. The effectiveness of the heavy metal salts is often more pronounced when they are precipitated together. To achieve the desired effect, concentrations of 0.001-10 mol% are usually sufficient, preferably 0.01-5 mol% _o If the heavy metal salts are added at a later stage in the production of the photographic material before casting, concentrations of 0.001 - 0.2, preferably 0.005-0.07 mol heavy metal _{salt, Z 0} B ₀ mercury (II) acetate per mol of silver salt.

Further, the image tone in the copying materials for the first and second methods can be improved. To this end So-called toners can be added to layers that "shift the image tone from brown to black", such compounds are e.g. 2H-phthalazinone- (1), barbituric acid, saccharin and 2-mercapto-benzoxazole, phthalimides and 2-acyl-2H-phthalazinone- (1).

Those in the German Offenlegungsschrift are also suitable Phthalazinone toners described in 2,220,597 and 2,220,618. The layers can also contain white pigments such as zinc oxide, silicon dioxide or titanium dioxide as fillers, to improve the whiteness and to influence the adhesion of the layers as well as terpene resins and organic acids to improve storage stability. Such layers are in the U.S. Patents 3,074,809 and 3,107,174

The usual natural or synthetic film-forming polymers are suitable as binders for the light-sensitive layer or _o for the heat-sensitive copying layer, ZoBc proteins, especially gelatine, cellulose derivatives, especially cellulose ethers, cellulose esters or carboxymethyl

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cellulose, alginic acid and derivatives thereof, starch ethers or Gallactomannen, also polyvinyl alcohol, polyvinylpyrrolidone, polyvinyl chloride, copolymers of vinyl chloride and vinyl acetate, polyvinyl acetate or wholly or partially saponified Polyvinyl acetate "or copolymers of vinyl acetate, copolymers of acrylonitrile and acrylamides, polyacrylic acid esters, polymethacrylic acid esters, polyethylene, etc.

In the absence of a binder, the reactants can also be incorporated into a fibrous web. In order to obtain desired special effects, pigments, fillers, fusible substances such as _o waxes, dyes and various other additives may be incorporated "

The layers can be applied as self-supporting layers or applied to a substrate "Suitable supports are, for example, _o paper, particularly baryta or laminated paper, Celluloseester such as cellulose triacetate, polyester, in particular based on ethylene terephthalate, glass, etc. _o

The silver salt, the reducing agents and the toner are preferably mixed together prior to encapsulation. You can However, they can also be applied separately in adjacent layers, from which one or more reductors - e.g. at Heating of the carrier film - being able to diffuse to the metal salt «

Heat-sensitive copying materials according to the present invention can be used in any process in which heat is information-wise applied or generated in the copying material, e.g. "B ₀ by means of hot bodies, such as a heating rod, or heat-generating radiation",

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Heat-sensitive, film-like copying materials according to The present invention are particularly suitable for thermographic copying of originals that absorb infrared Image markings included. When the original is contact-exposed with the present copy material with infrared radiation the infrared-absorbing image areas of the original are selectively heated and cause heat transfer in the adjacent thermosensitive film a visible color change resulting from the reaction of the organic Reducing agent results with the silver salt.

To expose the photosensitive layers, the in light sources commonly used in reproduction technology, such as halogen lamps, iodine quartz lamps or incandescent lamps, The spectral sensitivity of the photosensitive material depends on the nature of the sensitizer dyes used from ο

The exposed layers can be heated, for example, by guiding the exposed photosensitive layer over hot Plates or rollers or by irradiation with UR radiation.

The most favorable temperature and heating time depend of course on the nature of the image-forming compound or the composition of the light-insensitive silver salt-containing Copy material from; it can be determined by a few simple experiments.

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Example .

A mixture containing the following substances is ground in a ball mill for hours:

Ethyl acetate 40.0 g

Stearic acid 7.0 g

Polymethyl methacrylate 0.6 g

(the viscosity of a 5% solution by weight. in chloroform at 20 ⁰ C is 0,91cP) butyrate 0.2 g

(Degree of substitution of acetate and butyrate: 0.5 or 2.4 or the viscosity of a 20% solution in acetone is 15 cP) ' 0

f ¹¹ (tinting agent) 0.25 g

Zinc oxide 4.1. G

(average grain size: 10 / µm) Silver stearate 0.9 g

Before application, the following substances are added to the composition milled with the ball mill:

Methyl ethyl ketone. 20.0 g

Bisphenol 9 0.64 g

The final mixture is made on a polyethylene terephthalate

2 carriers applied at a ratio of 150 g per m.

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The applied layer is brought into thermally conductive contact with a paper bearing a text that is printed with printing ink containing carbon black and is contact-exposed with infrared radiation in a THERMOFAX copier _{or the like} . . "The Model 47-3M THERMOFAX copier is a thermographic copier from the Minnesota Mining & Manufacturing Company, St.", Paul, Minn./USA.

A neutral black, positive copy of strong is obtained Density ο

If one replaces the bisphenol 9 with another of the above Table, z "B _o by bisphenol 1, we obtain similar good results.

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Claims (1)

Claims Photographic material for the production of dry copies having a layer which is essentially light-insensitive reducible silver salts, reducing agents and optionally a toner and optionally a photosensitive heavy metal compound, optionally with a polymethine sensitizer is spectrally sensitized, characterized in that the reducing agent is a bisphenol of the following Formula included is: OH where mean: R ₁ = straight-chain or branched alkyl, cycloalkyl; R ₂ = straight-chain or branched alkyl, cycloalkyl, Aralkyl or phenyl;
R = hydrogen, alkyl or cycloalkyl and X = -S- or 4th
-C- where R. or R = hydrogen or alkyl, Material according to claim 1, characterized in that the light-insensitive silver salt is a silver salt long chain fatty acid is included. A-G 1129-20 409846/0519 3. Material according to claim 2, characterized in that silver behenate or SiTberstearat is included. Material according to Claim 1, characterized in that the layer contains a toner 5. Material according to claim 4, characterized in that the toner is 2H-phthalazinone (1) or a 2H-phthalazinone (1) derivative is included » 6. Material according to claim 1, characterized in that as a light-sensitive heavy metal compound, silver halide is included. 7. Material according to claim 6, characterized in that the light-sensitive heavy metal compound in amounts of 0.05-0.2% by weight, based on the weight of the
light-insensitive silver salt. A-G 1129 ■ - 21 - 409846/0519