CA1125561A - Photothermographic composition including a mixture containing benzyl alcohol or 2-phenoxyethanol speed-increasing solvent and an aromatic hydrocarbon solvent - Google Patents
Photothermographic composition including a mixture containing benzyl alcohol or 2-phenoxyethanol speed-increasing solvent and an aromatic hydrocarbon solventInfo
- Publication number
- CA1125561A CA1125561A CA319,279A CA319279A CA1125561A CA 1125561 A CA1125561 A CA 1125561A CA 319279 A CA319279 A CA 319279A CA 1125561 A CA1125561 A CA 1125561A
- Authority
- CA
- Canada
- Prior art keywords
- silver halide
- photothermographic
- solvent
- alcohol
- composition
- 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.)
- Expired
Links
Landscapes
- Non-Silver Salt Photosensitive Materials And Non-Silver Salt Photography (AREA)
Abstract
Abstract of the Disclosure In a photothermographic silver halide composition capable of being coated on a support comprising a hydro-philic photosensitive silver halide emulsion containing a gelatino peptizer with an organic solvent mixture, a hydro-phobic binder and an oxidation-reduction image-forming composition comprising (1) a silver salt of a long-chain fatty acid with (11) an organic reducing agent for said silver salt of a long-chain fatty acid, improvements are provided by a solvent mixture comprising a combination of (A) an alcohol photographic speed-increasing solvent which is a compound selected from the group sonsisting of benzyl alcohol photographic speed-increasing solvents and 2-phenoxyethanol speed-increasing solvents with (B) an aromatic hydrocarbon solvent that is compatible with the alcohol solvent said (C) 0 to 10% by weight of the solvent mixture of said hydrophobic binder. The discribed photo-thermographic composition can be prepared by very thoroughly mixing, such as ultrasonic wave mixing, (I) a hydrophilic photosensitive silver halide emulsion with (II) an organic solvent mixture comprising described (A), (B) and (C), and then very thoroughly mixing the resulting product with (III) comprising (a) a hydrophobic binder and (b) an oxidation-reduction image-forming composition comprising (i a silver salt of a long-chain fatty acid with (ii) an organic reducing agent, typically in an organic solvent. The photothermographic composition can be coated on a suitable support to provide a photothermographic element.
Description
l~S5~;1 PHOTOTHERMOGRAPHIC COMPOSITION AND PROC~SS
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
This invention relates to photothermographic silver halide materials as well as a method of preparing such materials. In one of its aspects it relates to a photothermographic silver halide composition capable of being coated comprising photosensitive silver halide and other components with a specified combination of solvents.
DESCRIPTION OF THE STATE OF THE ART
Photothermographic materials are well known in the photographic art. Photothermographic materials are also known as heat developable photographic materials. The photothermographic materials after imagewise exposure are heated to moderately elevated temperatures to produce a developed image in the absence of separate processing solutions or baths. The heat development can provide a developed silver image in the photothermographic material.
The term "material" as used herein, such as in photothermographic material, is intended to include elements and compositions. For instance, the use of "photothermo-graphic material" is intended to refer to photothermographic element and photothermographic composition.
An example of a known photothermographic silver halide material comprises (a) a hydrophilic photosensitive silver halide emulsion containing a gelatino peptizer with (b) an organic solvent mixture, (c) a hydrophobic binder and (d) an oxidation-reduction image-forming composition com-prising (i) a silver salt of a long-chain fatty acid, such as silver behenate or silver stearate, with (ii) an organic reducing agent, such as a phenolic reducing agent. It has been desirable to have hydrophilic photosensitive silver halide emulsion containing a gelatino peptizer in such a photothermographic material because of the higher photo-sensitivity of the silver halide emulsion and the ease ofcontrol in preparation of the emulsion based on conventional S56~L
aqueous silver halide gelatino emulsion technology. A
problem has been encountered in preparing such photothermo-graphic silver halide materials. This problem involves the mixing of a hydrophilic photosensitive silver halide emulsion containing a gelatino peptizer with a composition, as described, containing hydrophobic components including a hydrophobic binder, such as poly(vinyl butyral), and a silver salt of a long-chain fatty acid, such as a silver salt of behenic acid. Typically, when a hydrophilic photo-sensitive silver halide emulsion containing a gelatinopeptizer is mixed with such hydrophobic materials and then coated on a suitable support to produce a photothermographic element, the resulting photothermographic element produces a less than desired degree of photosensitivity, contrast and maximum density upon exposure and heat processing.
This problem has been encountered in photo-thermographic silver halide materials, as described in, for example, U.S. Patent 3,666,477 of Goffe, issued May 30, 1972.
Goffe proposed addition of alkylene oxide polymers and a mercaptotetrazole derivative to the photothermographic material to help provide increased photosensitivity.
In addition, a variety of organic solvents have been proposed in order to help prepare a photothermographic silver halide composition containing the described com-ponents. Such organic solvents that have been proposedinclude isopropanol, acetone, toluene, methanol, 2-methoxy-ethanol, chlorinated solvents, acetone-toluene mixtures and certain non-aqueous polar organic solvents. These solvents in photothermographic materials are described in, for example, U.K. Specifications 1,422,145; 1,460,868; and 1,354,186.
The described individual solvents, such as isopropanol, have not provided the desired improved described properties.
There has been a continuing need to provide improved relative speed and contrast with desired maximum image density.
S~l SUI~MARY OF T~E INVENTION
It has been found according to the invention that the described advantages are provided in a photothermo-graphic silver halide composition capable of being coated on a support comprising a hydrophilic photosensitive sllver halide emulsion containing a gelatino peptizer with an organic solvent mixture, a hydrophobic binder and an oxidation-reduction image-forming composition comprising (i) a silver salt of a long-chain fatty acid with (ii) an organic reducing agent for said silver salt of a long-chain fatty acid, wherein the solvent mixture comprises a combination of (A) an alcohol photographic speed-increasing solvent which is a compound selected from the group con-sisting of benzyl alcohol photographic speed-increasing solvents and 2-phenoxyethanol speed-increasing solvents, (B) an aromatic hydrocarbon solvent that is compatible with the benzyl alcohol solvent. An especially useful organic solvent mixture as described comprises (C) a minor portion, that is up to 10% by weight of the mixture, of the hydrophobic binder, such as poly(vinyl butyral).
A photothermographic composition according to the invention can be prepared by very thoroughly mixing, such as by ultrasonic wave mixing, (I) a hydrophilic photosensitive silver halide emulsion with (II) an organic solvent mixture comprising (A) an alcohol photographic speed-increasing solvent with (B) an aromatlc hydrocarbon solvent that ls compatible with the alcohol solvent and (C) O to 10~ by weight of said organlc solvent mixture of a hydrophobic binder, such as poly(vinyl butyral) and then very thoroughly mlxing the resultlng product with (III) comprising (a) a hydrophobic binder and (b) an oxidation-reduction image-formlng composition comprlsing (i) a silver salt of a long-chain fatty acld with (ii) an organic reducing agent, typically ln an organic solvent. A photothermographic element according to the invention can be prepared by coatlng the resultlng photothermographic composition on a suitable support.
~55~1 An image can be developed ln the photothermographic element after exposure by merely heatlng the photothermo-! graphic element to moderately elevated temperatures.
DETAILED DESCRIPTION 0~ THE INVENTION
A variety of descrlbed alcohol photographlc speed-increasing solvents are useful in the described solvent mlxture. It ls necessary that the described alcohol solvent be compatible with the described aromatlc hydrocarbon solvent and other components of the photothermographlc sllver hallde composition. Some alcohol solvents can be lnsufflclently soluble in the described composltion to be useful, such as chloro, hydroxy and nltro substltuted benzyl alcohols.
Selection of an optimum alcohol solvent will depend upon such factors as the particular components of the photo-thermographic composltion, the desired image, coatlng , condltlons, the partlcular aromatic hydrocarbon solvent, the particular photographic silver halide emulsion, and the concentration of the various components of the photothermo-,~ graphic composition. Combinatlons of alcohol solvents ' 20 can be useful if desired. Selection of an optlmum alcohol solvent can be carried out by a simple test in which the alcohol solvent is used in Example 1 ln place of benzyl alcohol. If the results of the alcohol solvent selected are slmilar to those of Example 1, the alcohol solvent is con-sidered to be at least satisfactory. The descrlbed alcohol photographlc speed-increaslng solvents can be selected from, for example, phenalkylols and phenoxyalkylols, ln which the alkylol contains 1 to 4 carbon atoms, and in which the phenyl group ls unsubstltuted or substltuted with lower alkyl, such as alkyl containing 1 to 4 carbon atoms, lower alkoxy, such as alkoxy containlng 1 to 4 carbon atoms, fluorosubstltuted lower alkyl or phenoxy.
The term "speed-increaslng" as used hereln with regard to the speed-lncreaslng solvent is intended to mean that the alcohol solvent provldes a hlgher relatlve speed -- . .
~1255~1 -4a-compared to a similar photothermographic composition containing no alcohol solvent.
The described benzyl alcohol solvent can be sub-stituted benzyl alcohol or can be benzyl alcohol which is substituted with a group which does not adversely affect the desired solvent or sensitometric properties produced by the benzyl alcohol derivative. Examples of substituents which do not adversely affect the desired properties include methyl, phenoxy, trifluoromethyl, methoxy and ethoxy.
Unsubstituted benzyl alcohol is preferred.
A variety of aromatic hydrocarbon solvents are userul ln the described solvent mlxture wlth the descrlbed alcohol speed-lncreaslng solvent. The aromatlc hydrocarbon solvent must be compatible wlth the alcohol solvent and other components of the photothermographic composltion wlthout adversely affecting the deslred solvent and sen-sltometric properties produced by the solvent mixture. The optimum aromatic hydrocarbon solvent can be selected based on such factors as the particular components of the photo-thermographic compositlon, the particular alcohol solvent, coating conditions for the photothermographic composition, the particular photosensitive silver halide emulsion and the llke. Combinations of aromatic hydrocarbon solvents can be useful if desired.
Examples of useful aromatic hydrocarbon solvents include toluene, xylene and benzene. Toluene ls preferred as a solvent with benzyl alcohol.
Other solvents that are useful in place of or in combination with the described aromatic hydrocarbon solvents include butyl acetate, dlmethyl acetamide and dimethyl-formamide. These solvents can be useful in combination if - desired. However, an aromatic hydrocarbon solvent, such as toluene, is preferred with the described alcohol solvent, such as benzyl alcohol.
A range of concentration Or described alcohol - solvent is useful in the described photothermographic silver halide composition. Typlcally, the alcohol solvent is useful at a concentration which produces a photothermographic element as coated containing the alcohol within the range of 30 about 0.50 grams/m2 to about 2.80 grams/m2. An especially useful concentration of alcohol solvent, such as benzyl alcohol, is within the range of about 0.8 grams to about 1.35 grams of alcohol solvent/m2 of support of the described photothermographic element. ~he optimum concentration of alcohol solvent will depend upon the particular components of the photothermographic material, coating conditlons, deslred image, the partlcular aromatic hydrocarbon solvent, the partlcular alcohol solvent and the like.
a~
55~1 A range of concentratlon of aromatic hydrocarbon solvent is useful in the described photothermographic silver halide composition also. The concentration of aromatic hydrocarbon solvent is typically within the range of 30% to about 80% by weight of total photothermo-graphic composition. A preferred concentration of aromatic hydrocarbon solvent, such as toluene, is within the range of about 70% to about 80% by weight of total photothermo-graphic composition. The optimum concentration of aromatic hydrocarbon solvent will depend upon the described factors that relate to selection of the optimum concentration of described alcohol solvent.
A range of ratios of described alcohol solvent to aromatic hydrocarbon solvent is useful in the described solvent mixture at the time of mixing the solvent mixture with the silver halide. Typically, the ratio of alcohol solvent to aromatic hydrocarbon solvent at this point is within the range of about 1:10 to about 1:30. A preferred ratio of described alcohol solvent to aromatic hydrocarbon solvent is within the range of about 1:15 to about 1:25.
An optimum ratio of alcohol solvent to aromatic hydrocarbon solvent will depend upon such factors as the particular solvents, the specific components of the photothermographic silver halide composition, coating conditions, the desired image, the particular silver halide emulsion and the like.
Typically, in the described photothermographic composition, that is prior to coating onto a suitable support, the ratio of alcohol solvent to hydrocarbon solvent is within the range of about 1:50 to 1:200 with a preferred range of 1:75 to 1:150.
The photothermographic materials according to the invention comprise a photosensitive component which consists essentially of photosensitive silver halide. The photo-sensitive silver halide is in the form of a hydrophilic photosensitive silver halide emulsion containing a gelatino S5~i1 peptizer. The photosensitive silver halide is especially useful due to its high degree of photosensitivity compared to other photosensitive components. A typical concentration of hydrophilic photosensitive silver halide emulsion con-taining a gelatino peptizer in a photothermographic com-position according to the invention is within the range of about 0.2 to about l.O mole of photosensitive silver halide per mole of the described silver salt of a long-chain fatty acid in the photothermographic material. Other photo-sensitive materials can be useful in combination with thedescribed photosensitive silver halide if desired. Preferred photosensitive silver halides are silver chloride, silver bromoiodide, silver bromide, silver chlorobromoiodlde or mixtures thereof. For purposes of the invention, silver iodide is also considered to be a photosensitive silver halide. A range of grain size of photosensitive silver halide from very coarse grain to very fine grain silver halide is useful. Very fine grain silver halide is typically preferred.
The hydrophilic photosensitive silver halide emulsion containing a gelatino peptizer can be prepared by any of the procedures known in the photographic art which involve the preparation of photographic silver hallde gelatino emulsion. Useful procedures and forms of photo-sensitive silver halide gelatino emulsions for purposes of the invention are described in, for example, the Product Licensing Index, ~olume 92, December 1971, Publication 9232 on page 107, published by Industrial Opportunities Limited, Homewell, Havant Hampshire, PO9 lEF, UK. The photographic silver halide, as described, can be washed or unwashed, can be chemically sensitized using chemical sensitization procedures and materials known in the photographic art, can be protected against the production of fog and stabilized against loss of sensitiVity during keeping as described in the mentioned Product Licensing Index publication.
l~ZS5~L
A hydrophilic photosensitive silver halide emulsion containing a gelatino peptizer which contains a low concen-tration of gelatin is often very useful. The concentration of gelatin which is very useful is typically within the range of about 9 to about 15 grams per mole of silver.
The term "hydrophilic" is intended herein to mean that the photosensitive silver halide emulsion con-taining a gelatino peptizer is compatible with an aqueous solvent.
The gelatino peptizer that is useful with the photosensitive silver halide emulsion can comprise a variety of gelatino peptizers known in the photographic art. The gelatino peptizer can be, for example, phthalated gelatin or non-phthalated gelatin. Other gelatino peptizers that are useful include acid or base hydrolyzed gelatins. A non-phthalated gelatin peptizer is especially useful with the described photosensitive silver halide emulsion.
The photosensitive silver halide emulsion can con-tain a range of concentration of the gelatino peptizer.
Typically, the concentration of the gelatino peptizer is within the range of about 5 grams to about 20 grams of gelatino peptizer, such as gelatin, per mole of silver in the silver halide emulsion. This is described herein as a low-gel silver halide emulsion. An especially useful concentration of gelatino peptizer is within the range of about 9 to about 15 grams of gelatino peptizer per mole of silver in the silver halide emulsion. The optimum concentration of the gelatino peptizer will depend upon such factors as the particular photosensitive silver halide, the desired image, the particular components of the photothermographic com-position, coating conditions, the particular benzyl alcohol solvent and the particular aromatic hydrocarbon solvent.
The silver halide emulsion pH can be maintained within a range of pH. Typically, the silver halide emulsion pH is maintained within the range of about 5.0 to about 6.2 during the emulsion precipitation step. Lower pH values may cause undesired coagulation and higher pH values may cause undesirable grain growth.
l~S~l g The temperature of the reactlon vessel within whlch the silver hallde emulslon ls prepared ls typlcally malntalned wlthln a temperature range of~about 35C to about 75C durlng the composltlon preparatlon. The temperature range and duratlon of the preparatlon can be altered to produce the deslred emulslon graln slze and deslred com-position properties. The silver hallde emulslon can be prepared by means of emulsion preparatlon technlques and apparatus known in the photographlc art.
An especlally useful method for preparatlon of the photothermographlc composltlon ls by a slmultaneous double-~et emulslon additlon of the components (I) and (II) lnto a Jacket enclosing an ultrasonic means for exposlng the composition to hlgh frequency waves. After combinatlon ln the ~acket and thorough mlxlng due to the ultrasonlc waves, ? ~ the mlxture can be wlthdrawn and recirculated through the ~acket encloslng the ultrasonlc m~ans for addltional mixlng or wlthdrawn lmmedlately and comblned readlly wlth other rl addenda to produce the deslred photothermographlc composltlon.
~'. 20 A variety of hydrophobic binders are useful in the described photothermographlc materials. The blnders that are useful include various colloids alone or in comblnatlon as vehicles and/or binding agents. The hydrophobic binders which are suitable include transparent or translucent materials. Useful binders lnclude polymers of alkylacrylates and methacrylates, acryllc acld, sulfoalkylacrylates or methacrylates, and those whlch have crosslinking sites that facllltate hardenlng or curlng. Other useful hydrophoblc blnders lnclude hlgh molecular welght materlals and reslns, such as poly(vlnyl butyral), cellulose acetate butyrate, poly(methyl methacrylate~, poly(styrene), poly(vlnyl chlorlde), chlorinated rubber, poly(lsobutylene), butadlene-styrene copolymers, vinyl chlorlde-vinyl acetate copolymers, copolymers of vinyl acetate, vinyl chloride and maleic anhydride and the like. It ls lmportant that the hydrophoblc blnder not adversely a~fect the sensitometric or other ~.
~.
55ti1 desired properties of the described photothermographic material. Poly(vinyl butyral) is especially useful.
This is available under the trade~e "BUTVAR" from The Monsanto Company, U.S.A.
A range of concentration of hydrophobic binder can be useful in the photothermographic silver halide materials according to the invention. Typically, the concentration of hydrophobic binder in a photothermographic silver halide com-position according to the invention is within the range of about 20 to about 65 mg/dm2. An optimum concentration of the described binder can vary depending upon such factors as the particular binder, other components of the photothermo-graphic material, coating conditions, desired image, processing temperature and conditions and the like.
If desired, a portion of the photographic silver halide in the photothermographic composition according to the invention can be prepared in situ in the photothermographic material. The photothermographic com-position, for example, can contain a portion of the photo-graphic silver halide that is prepared in or on one or more of the other components of the described photothermographic material rather than prepared separate from the described components and then admixed with them. Such a method of preparing silver halide in situ is described in, for example, U.S. Patent 3,457,075 of Morgan et al, issued July 22, 1969.
The described photothermographic composition com-prises an oxidation-reduction image-forming combination con-taining a long-chain fatty acid silver salt with a suitable reducing agent. The oxidation-reduction reaction resulting from this combination upon heating is believed to be catalyzed by the latent image silver from the photosensitive silver halide produced upon imagewise exposure of the photo-thermographic material followed by overall heating of the photothermographic material. The exact mechanism of image formation is not fully understood.
~!255~1 A variety of silver salts of long-chain fatty acids are useful in the photothermographic materials according to the lnvention. The term "lon~-chaln" as used hereln ls lntended to refer to a ratty acid containlng 12 to 30 carbon atoms and which is typically resistant to darkenlng upon exposure to light. Use~ul long-chain fatty acld sllver salts lnclude, for example, silver stearate, sllver behenate, sllver caprate, silver hydroxystearate, silver myrlstate and silver palmltate. A minor proportlon of another sllver salt oxidizing agent which is not a long-chain fatty acld sllver salt can be useful in comblnatlon wlth the sllver salt Or the long-chain fatty acld lf desired. Such silver salts which can be useful in combination with the descrlbed sllver salts of a long-chain fatty acid include, for example, ; 15 silver benzotriazole, silver imidazole, silver benzoate and ~ the like. Combinations of silver salts of long-chain fatty ; acids can be useful in the described photothermographlc materials if desired.
~, A variety of organic reducing agents are useful in the described photothermographic sllver hallde materlals accordlng to the lnvention. These are typically silver halide developing agents which produce the desired oxidation-reduction image-forming reactlon upon exposure and heating of the descrlbed photothermographic silver hallde material. Examples of useful reduclng agents lnclude polyhydroxybenzenes, such as hydroquinone and alkyl sub-stltuted hydroquinones; catechols and pyrogallol; phenylene-dlamlne developing agents; amlnophenol developlng agents;
ascorblc acld developlng agents, such as ascorblc acid and ascorbic acld ketals and other ascorblc acld derlvatives;
hydroxylamlne developlng agents; 3-pyrazolidone developlng agents such as l-phenyl-3-pyrazolldone and 4-methyl-4-hydroxymethyl-l-phenyl-3-pyrazolldone; hydroxytetronlc acld and hydroxytetronamide developlng agents; reductone developlng agents; bls-B-naphthol reducing agents; sulfon-amldophenol reduclng agents and the llke. Comblnatlons Or , ~".....
55t~1 organlc reduclng agents can be useful ln the described photothermographlc sllver hallde materlals. Sulfonamldo-phenol developlng agents, such as descrlbed ln Belglan Patent 802,519 lssued January 18, 1974, can be especlally useful ln the photothermographlc sllver hallde composltlon.
A range of concentratlon Or the organlc reduclng agent can be useful ln the descrlbed photothermographlc sllver hallde materlals. The concentratlon of organlc reduclng agent ls typically withln the range of about 5 mg/dm2 to about 20 mg/dm2, such as wlthln the range of about 10 to about 17 mg/dm2. The optlmum concentration of organlc reduclng agent wlll depend upon such factors as the particular long-chaln fatty acld, the deslred lmage, processin~
condltlons, the partlcular solvent mlxture, coating condltlons and the llke.
The order of addltion of the descrlbed components for preparlng the photothermographic compositlon before coating the composition onto a sultable support ls lmportant to obtain optimum photographic speed, contrast and maxlmum density. In an especlally useful method accordlng to the invention the low-gel silver halide emulsion ls added to an ultrasonlc mixing means through one lnlet and a solvent mixture containing toluene, up to about 10% by weight poly(vlnyl butyral) and benzyl alcohol ls added through another lnlet. The low-gel silver hallde ls dlspersed thoroughly ln thls environment by ultrasonlc waves. The resultlng product is then combined with the remainlng components of the deslred photothermographlc composition.
If the low-gel silver halide is not dispersed as described before addlng the other components, the sllver hallde gralns ln the composltlon have a tendency to clump together and preclpltate to the bottom of the contalner ln whlch the composltion is mlxed.
~, l~St~l ~13-A variety of mixing means are useful for preparing the descrlbed composltlons. However, the mlxlng means should be one whlch provldes very thorough mixing, such as an ultrasonlc mlxlng means. Other mlxlng means than ultrasonlc mixing means that can be useful are commerclally avallable - colloid mlll mixing means and dlspersator mixing means known in the photographlc art. A blender, such as a blender known under the trade name of "Waring" blender, does not produce the very thorough mixlng that ls desired in most cases.
It is desirable, ln some cases, to have what ls descrlbed as a tonlng agent, also known as an actlvator-; toning agent, in the photothermographlc materlal accordlng to the invention. Combinations of toning agents can often be useful. Typical toning agents lnclude, for e~ample, phthalimide, succlnlmlde, N-hydroxyphthallmide, N-hydroxy-1,8-naphthalimide, N-hydroxysuccinimide, 1-(2H)-phthalazinone and phthalazinone derivatlves.
Photothermographlc materials according to the invention can contain other addenda that are userul ln imaging. Suitable addenda in the descrlbed photothermo-graphlc materials include development modl~lers that functlon as speed-lncreasing compounds, hardeners, anti-static layers, plasticizers and lubricants, coating alds, brighteners, spectral sensitlzing dyes, absorbing and fllter dyes, matting agents and the like.
It is useful in certain cases to include a stabilizer in the described photothermographic material.
This can help in stabilizatlon of a developed lmage. Com-binations of stabillzers can be useful lf deslred. Typlcal stabillzers or stabilizer precursors include certaln halogen compounds, such as tetrabromobutane and 2-(tribromo-methylsulfonyl), benzothiazole, which provide improved post-processing stabllity and azothioethers and blocked azollne thlone stabllizer precursors.
The photothermographlc elements accordlng to the inventlon can comprlse a varlety Or supports which can 1~2S5~1 tolerate the processing temperatures useful in developing an image. Typical supports include cellulose ester, poly(vinyl acetal), poly(ethylene terephthalate), poly-carbonate and polyester film supports. Related film and resinous support materials, as well as paper, glass, metal and the like supports which can withstand the described processing temperatures are also useful. Typically a flexible support is most useful.
The photothermographic compositions can be coated on a suitable support by coating procedures known in the photographic art including dip coating, airknife coating, curtain coating or extrusion coating using hoppers. If desired, two or more layers can be coated simultaneously.
The described silver halide and oxidation-reduction image-forming combination can be in any suitable location in the photothermographic element according to the invention which produces the desired image. In some cases it can be desirable to include certain percentages of the described reducing agent, the silver salt oxidizing agent and/or other addenda in a protective layer or overcoat layer over the layer containing the other components of the element as described. The components, however, must be in a location which enables their desired interaction upon processing.
It is necessary that the photosensitive silver halide, as described, and other components of the imaging combination be "in reactive association" with each other in order to produce the desired image. The term "in reactive association", as employed herein, is intended to mean that the photosensitive silver halide and the image-forming combination are in a location with respect to each other which enables the desired processing and produces a useful image.
A useful embodiment of the invention is a photo-thermographic silver halide composition capable of being coated on a support comprising ~a~ an aqueous photosensitive - ~2S~til silver hallde emulsion contalnlng a gelatlno peptlzer wlth (b) an organic solvent mixture comprlslng a comblnatlon Or a benzyl alcohol photographlc speed-lncreasing solven~, such as benzyl alcohol, with toluene and up to 4~ by welght 5 poly(vinyl butyral), (c) a hydrophobic polymeric blnder conslsting essentially of poly(vinyl butyral) and (d) an oxidation-reduction image-rorming combination comprlslng (i) a silver salt or a long-chain fatty acld conslstlng essentially of silver behenate wlth (11) an organlc reducing 10 agent consisting essentially of a sulfonamldophenol. This composition can be coated on a suitable support to produce a photothermographic element according to the lnventlon.
Another embodiment of the inventlon is a method of preparing a photothermographlc element comprising coating the resulting 15 composition onto a suitable support to produce a photothermo-graphic element as desired.
A variety of imagewise exposure means are useful ; wlth the photothermographic materials according to the invention. The imaging means according to the lnvention 20 can be any suitable source of radiation to which the photo-thermographic material is sensitive. The imaging materials according to the invention are typically sensitive to the t ultraviolet and blue regions of the spectrum and exposure means which provide this radiation are preferred. Typically, 25 however, if a spectral sensitizing dye or combination of spectral sensitizing dyes are present in the photothermo-graphic material, exposure means using other ranges of the electromagnetic spectrum can be useful. Typically, a photo-thermographic material according to the invention is exposed 30 imagewise with a visible light source, such as a tungsten lamp. Other sources of radiation can be useful and include, for instance, lasers, electron beams, X-ray sources and the like. The photothermographic materials are typlcally exposed imagewise to produce a developable latent image.
:
llZ55til A visible image can be developed in the photo-thermographic material according to the invention withln a short time, such as within several seconds, merely by heating the photothermographic material to moderately elevated temperatures. For example, the exposed photothermo-graphic material can be heated to a temperature within the range of about 100C to about 200C, such as a temperature within the range of about 110C to about 140C. Heating is carried out until a desired image is developed, typically within about 2 to about 30 seconds, such as about 2 to about 10 seconds. Selection of an optimum processing time and temperature will depend upon such factors as the desired image, particular components of the photothermographic element, the particular latent image and the like.
A variety of means can be useful to produce the necessary heating of the described photothermographic material to develop the desired image. The heating means can be a simple hot plate, iron, roller, infrared heating means, hot air heating means or the like.
Processing according to the invention is typically carried out under ambient conditions of pressure and humidity. Pressures and humidity outside normal atmospheric conditions can be useful if desired; however, normal atmospheric conditions are preferred.
The following examples are included for a further understanding of the invention.
Example 1 This illustrates the invention.
A silver behenate/behenic acid dispersion (C) was prepared by blending the following components:
acetone 250 ml toluene 250 ml poly(vinyl butyral~ 30.3 g behenic acid 16.0 g 35 silver behenate 42.0 g ~55~jl A silver hallde gelatlno photosensltlve dispersion (Z) was prepared as follows: An aqueous solution of 10 3 molar lithium bromide was added to 0.02 mole of a 400 A silver bromoiodlde (6 mole % lodlde) gelatino emulsion (40 grams non-phthalated gelatin per silver mole) to produce a total weight of 200 grams. The resulting mixture was stlrred for 15 minutes at 40C and a pH of 6.1 with a pAg of 8.4. The emulsion was centrifuged for 20 minutes at 3000 rpm. The resulting supernatant was discarded and a 100 mg sample of the wet centrifuged silver halide emulsion was treated with ultrasonic waves for 30 seconds in the presence of 3 ml of a solvent mixture containing toluene (87 grams) and 4~ by weight poly(vinyl butyral) with 4 grams of benzyl alcohol.
Thls resultlng sllver hallde dlsperslon (Z) was combined with the following components:
acetone/toluene (1:9 parts 0.15 ml by volume) solution con-~ taining 0.01% by weight - 20 3-ethyl-2-thio-2,4-oxazolidinedione (speed-increasing addenda) acetone/toluene (1:9 parts 0.50 ml by volume) solution con-taining 0.01% by weight 3-ethyl-5-(3-ethyl-2-benzoxazolylideneethylidene)-- l-phenyl-2-thiohydantoin (sensitizing dye) silver behenate dispersion C 3.6 ml (described above) (oxidizing agent) The resulting composition was mixed by shaking for several mlnutes. The dispersion was combined with the following solutions and coated on an unsubbed poly(ethylene terephthalate) film support at a o.oo8 inch (8 mils) wet coatlng thlckness:
~'~
l~Z55~1 acetone~toluene (1:1 parts Q.50 ml by volume) solution con-taining 25% by weight 2,6-dichloro-4-benzenesulfon-amidophenol (reducing agent) toluene solution containing 2 drops siloxane surfactant (containing
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
This invention relates to photothermographic silver halide materials as well as a method of preparing such materials. In one of its aspects it relates to a photothermographic silver halide composition capable of being coated comprising photosensitive silver halide and other components with a specified combination of solvents.
DESCRIPTION OF THE STATE OF THE ART
Photothermographic materials are well known in the photographic art. Photothermographic materials are also known as heat developable photographic materials. The photothermographic materials after imagewise exposure are heated to moderately elevated temperatures to produce a developed image in the absence of separate processing solutions or baths. The heat development can provide a developed silver image in the photothermographic material.
The term "material" as used herein, such as in photothermographic material, is intended to include elements and compositions. For instance, the use of "photothermo-graphic material" is intended to refer to photothermographic element and photothermographic composition.
An example of a known photothermographic silver halide material comprises (a) a hydrophilic photosensitive silver halide emulsion containing a gelatino peptizer with (b) an organic solvent mixture, (c) a hydrophobic binder and (d) an oxidation-reduction image-forming composition com-prising (i) a silver salt of a long-chain fatty acid, such as silver behenate or silver stearate, with (ii) an organic reducing agent, such as a phenolic reducing agent. It has been desirable to have hydrophilic photosensitive silver halide emulsion containing a gelatino peptizer in such a photothermographic material because of the higher photo-sensitivity of the silver halide emulsion and the ease ofcontrol in preparation of the emulsion based on conventional S56~L
aqueous silver halide gelatino emulsion technology. A
problem has been encountered in preparing such photothermo-graphic silver halide materials. This problem involves the mixing of a hydrophilic photosensitive silver halide emulsion containing a gelatino peptizer with a composition, as described, containing hydrophobic components including a hydrophobic binder, such as poly(vinyl butyral), and a silver salt of a long-chain fatty acid, such as a silver salt of behenic acid. Typically, when a hydrophilic photo-sensitive silver halide emulsion containing a gelatinopeptizer is mixed with such hydrophobic materials and then coated on a suitable support to produce a photothermographic element, the resulting photothermographic element produces a less than desired degree of photosensitivity, contrast and maximum density upon exposure and heat processing.
This problem has been encountered in photo-thermographic silver halide materials, as described in, for example, U.S. Patent 3,666,477 of Goffe, issued May 30, 1972.
Goffe proposed addition of alkylene oxide polymers and a mercaptotetrazole derivative to the photothermographic material to help provide increased photosensitivity.
In addition, a variety of organic solvents have been proposed in order to help prepare a photothermographic silver halide composition containing the described com-ponents. Such organic solvents that have been proposedinclude isopropanol, acetone, toluene, methanol, 2-methoxy-ethanol, chlorinated solvents, acetone-toluene mixtures and certain non-aqueous polar organic solvents. These solvents in photothermographic materials are described in, for example, U.K. Specifications 1,422,145; 1,460,868; and 1,354,186.
The described individual solvents, such as isopropanol, have not provided the desired improved described properties.
There has been a continuing need to provide improved relative speed and contrast with desired maximum image density.
S~l SUI~MARY OF T~E INVENTION
It has been found according to the invention that the described advantages are provided in a photothermo-graphic silver halide composition capable of being coated on a support comprising a hydrophilic photosensitive sllver halide emulsion containing a gelatino peptizer with an organic solvent mixture, a hydrophobic binder and an oxidation-reduction image-forming composition comprising (i) a silver salt of a long-chain fatty acid with (ii) an organic reducing agent for said silver salt of a long-chain fatty acid, wherein the solvent mixture comprises a combination of (A) an alcohol photographic speed-increasing solvent which is a compound selected from the group con-sisting of benzyl alcohol photographic speed-increasing solvents and 2-phenoxyethanol speed-increasing solvents, (B) an aromatic hydrocarbon solvent that is compatible with the benzyl alcohol solvent. An especially useful organic solvent mixture as described comprises (C) a minor portion, that is up to 10% by weight of the mixture, of the hydrophobic binder, such as poly(vinyl butyral).
A photothermographic composition according to the invention can be prepared by very thoroughly mixing, such as by ultrasonic wave mixing, (I) a hydrophilic photosensitive silver halide emulsion with (II) an organic solvent mixture comprising (A) an alcohol photographic speed-increasing solvent with (B) an aromatlc hydrocarbon solvent that ls compatible with the alcohol solvent and (C) O to 10~ by weight of said organlc solvent mixture of a hydrophobic binder, such as poly(vinyl butyral) and then very thoroughly mlxing the resultlng product with (III) comprising (a) a hydrophobic binder and (b) an oxidation-reduction image-formlng composition comprlsing (i) a silver salt of a long-chain fatty acld with (ii) an organic reducing agent, typically ln an organic solvent. A photothermographic element according to the invention can be prepared by coatlng the resultlng photothermographic composition on a suitable support.
~55~1 An image can be developed ln the photothermographic element after exposure by merely heatlng the photothermo-! graphic element to moderately elevated temperatures.
DETAILED DESCRIPTION 0~ THE INVENTION
A variety of descrlbed alcohol photographlc speed-increasing solvents are useful in the described solvent mlxture. It ls necessary that the described alcohol solvent be compatible with the described aromatlc hydrocarbon solvent and other components of the photothermographlc sllver hallde composition. Some alcohol solvents can be lnsufflclently soluble in the described composltion to be useful, such as chloro, hydroxy and nltro substltuted benzyl alcohols.
Selection of an optimum alcohol solvent will depend upon such factors as the particular components of the photo-thermographic composltion, the desired image, coatlng , condltlons, the partlcular aromatic hydrocarbon solvent, the particular photographic silver halide emulsion, and the concentration of the various components of the photothermo-,~ graphic composition. Combinatlons of alcohol solvents ' 20 can be useful if desired. Selection of an optlmum alcohol solvent can be carried out by a simple test in which the alcohol solvent is used in Example 1 ln place of benzyl alcohol. If the results of the alcohol solvent selected are slmilar to those of Example 1, the alcohol solvent is con-sidered to be at least satisfactory. The descrlbed alcohol photographlc speed-increaslng solvents can be selected from, for example, phenalkylols and phenoxyalkylols, ln which the alkylol contains 1 to 4 carbon atoms, and in which the phenyl group ls unsubstltuted or substltuted with lower alkyl, such as alkyl containing 1 to 4 carbon atoms, lower alkoxy, such as alkoxy containlng 1 to 4 carbon atoms, fluorosubstltuted lower alkyl or phenoxy.
The term "speed-increaslng" as used hereln with regard to the speed-lncreaslng solvent is intended to mean that the alcohol solvent provldes a hlgher relatlve speed -- . .
~1255~1 -4a-compared to a similar photothermographic composition containing no alcohol solvent.
The described benzyl alcohol solvent can be sub-stituted benzyl alcohol or can be benzyl alcohol which is substituted with a group which does not adversely affect the desired solvent or sensitometric properties produced by the benzyl alcohol derivative. Examples of substituents which do not adversely affect the desired properties include methyl, phenoxy, trifluoromethyl, methoxy and ethoxy.
Unsubstituted benzyl alcohol is preferred.
A variety of aromatic hydrocarbon solvents are userul ln the described solvent mlxture wlth the descrlbed alcohol speed-lncreaslng solvent. The aromatlc hydrocarbon solvent must be compatible wlth the alcohol solvent and other components of the photothermographic composltion wlthout adversely affecting the deslred solvent and sen-sltometric properties produced by the solvent mixture. The optimum aromatic hydrocarbon solvent can be selected based on such factors as the particular components of the photo-thermographic compositlon, the particular alcohol solvent, coating conditions for the photothermographic composition, the particular photosensitive silver halide emulsion and the llke. Combinations of aromatic hydrocarbon solvents can be useful if desired.
Examples of useful aromatic hydrocarbon solvents include toluene, xylene and benzene. Toluene ls preferred as a solvent with benzyl alcohol.
Other solvents that are useful in place of or in combination with the described aromatic hydrocarbon solvents include butyl acetate, dlmethyl acetamide and dimethyl-formamide. These solvents can be useful in combination if - desired. However, an aromatic hydrocarbon solvent, such as toluene, is preferred with the described alcohol solvent, such as benzyl alcohol.
A range of concentration Or described alcohol - solvent is useful in the described photothermographic silver halide composition. Typlcally, the alcohol solvent is useful at a concentration which produces a photothermographic element as coated containing the alcohol within the range of 30 about 0.50 grams/m2 to about 2.80 grams/m2. An especially useful concentration of alcohol solvent, such as benzyl alcohol, is within the range of about 0.8 grams to about 1.35 grams of alcohol solvent/m2 of support of the described photothermographic element. ~he optimum concentration of alcohol solvent will depend upon the particular components of the photothermographic material, coating conditlons, deslred image, the partlcular aromatic hydrocarbon solvent, the partlcular alcohol solvent and the like.
a~
55~1 A range of concentratlon of aromatic hydrocarbon solvent is useful in the described photothermographic silver halide composition also. The concentration of aromatic hydrocarbon solvent is typically within the range of 30% to about 80% by weight of total photothermo-graphic composition. A preferred concentration of aromatic hydrocarbon solvent, such as toluene, is within the range of about 70% to about 80% by weight of total photothermo-graphic composition. The optimum concentration of aromatic hydrocarbon solvent will depend upon the described factors that relate to selection of the optimum concentration of described alcohol solvent.
A range of ratios of described alcohol solvent to aromatic hydrocarbon solvent is useful in the described solvent mixture at the time of mixing the solvent mixture with the silver halide. Typically, the ratio of alcohol solvent to aromatic hydrocarbon solvent at this point is within the range of about 1:10 to about 1:30. A preferred ratio of described alcohol solvent to aromatic hydrocarbon solvent is within the range of about 1:15 to about 1:25.
An optimum ratio of alcohol solvent to aromatic hydrocarbon solvent will depend upon such factors as the particular solvents, the specific components of the photothermographic silver halide composition, coating conditions, the desired image, the particular silver halide emulsion and the like.
Typically, in the described photothermographic composition, that is prior to coating onto a suitable support, the ratio of alcohol solvent to hydrocarbon solvent is within the range of about 1:50 to 1:200 with a preferred range of 1:75 to 1:150.
The photothermographic materials according to the invention comprise a photosensitive component which consists essentially of photosensitive silver halide. The photo-sensitive silver halide is in the form of a hydrophilic photosensitive silver halide emulsion containing a gelatino S5~i1 peptizer. The photosensitive silver halide is especially useful due to its high degree of photosensitivity compared to other photosensitive components. A typical concentration of hydrophilic photosensitive silver halide emulsion con-taining a gelatino peptizer in a photothermographic com-position according to the invention is within the range of about 0.2 to about l.O mole of photosensitive silver halide per mole of the described silver salt of a long-chain fatty acid in the photothermographic material. Other photo-sensitive materials can be useful in combination with thedescribed photosensitive silver halide if desired. Preferred photosensitive silver halides are silver chloride, silver bromoiodide, silver bromide, silver chlorobromoiodlde or mixtures thereof. For purposes of the invention, silver iodide is also considered to be a photosensitive silver halide. A range of grain size of photosensitive silver halide from very coarse grain to very fine grain silver halide is useful. Very fine grain silver halide is typically preferred.
The hydrophilic photosensitive silver halide emulsion containing a gelatino peptizer can be prepared by any of the procedures known in the photographic art which involve the preparation of photographic silver hallde gelatino emulsion. Useful procedures and forms of photo-sensitive silver halide gelatino emulsions for purposes of the invention are described in, for example, the Product Licensing Index, ~olume 92, December 1971, Publication 9232 on page 107, published by Industrial Opportunities Limited, Homewell, Havant Hampshire, PO9 lEF, UK. The photographic silver halide, as described, can be washed or unwashed, can be chemically sensitized using chemical sensitization procedures and materials known in the photographic art, can be protected against the production of fog and stabilized against loss of sensitiVity during keeping as described in the mentioned Product Licensing Index publication.
l~ZS5~L
A hydrophilic photosensitive silver halide emulsion containing a gelatino peptizer which contains a low concen-tration of gelatin is often very useful. The concentration of gelatin which is very useful is typically within the range of about 9 to about 15 grams per mole of silver.
The term "hydrophilic" is intended herein to mean that the photosensitive silver halide emulsion con-taining a gelatino peptizer is compatible with an aqueous solvent.
The gelatino peptizer that is useful with the photosensitive silver halide emulsion can comprise a variety of gelatino peptizers known in the photographic art. The gelatino peptizer can be, for example, phthalated gelatin or non-phthalated gelatin. Other gelatino peptizers that are useful include acid or base hydrolyzed gelatins. A non-phthalated gelatin peptizer is especially useful with the described photosensitive silver halide emulsion.
The photosensitive silver halide emulsion can con-tain a range of concentration of the gelatino peptizer.
Typically, the concentration of the gelatino peptizer is within the range of about 5 grams to about 20 grams of gelatino peptizer, such as gelatin, per mole of silver in the silver halide emulsion. This is described herein as a low-gel silver halide emulsion. An especially useful concentration of gelatino peptizer is within the range of about 9 to about 15 grams of gelatino peptizer per mole of silver in the silver halide emulsion. The optimum concentration of the gelatino peptizer will depend upon such factors as the particular photosensitive silver halide, the desired image, the particular components of the photothermographic com-position, coating conditions, the particular benzyl alcohol solvent and the particular aromatic hydrocarbon solvent.
The silver halide emulsion pH can be maintained within a range of pH. Typically, the silver halide emulsion pH is maintained within the range of about 5.0 to about 6.2 during the emulsion precipitation step. Lower pH values may cause undesired coagulation and higher pH values may cause undesirable grain growth.
l~S~l g The temperature of the reactlon vessel within whlch the silver hallde emulslon ls prepared ls typlcally malntalned wlthln a temperature range of~about 35C to about 75C durlng the composltlon preparatlon. The temperature range and duratlon of the preparatlon can be altered to produce the deslred emulslon graln slze and deslred com-position properties. The silver hallde emulslon can be prepared by means of emulsion preparatlon technlques and apparatus known in the photographlc art.
An especlally useful method for preparatlon of the photothermographlc composltlon ls by a slmultaneous double-~et emulslon additlon of the components (I) and (II) lnto a Jacket enclosing an ultrasonic means for exposlng the composition to hlgh frequency waves. After combinatlon ln the ~acket and thorough mlxlng due to the ultrasonlc waves, ? ~ the mlxture can be wlthdrawn and recirculated through the ~acket encloslng the ultrasonlc m~ans for addltional mixlng or wlthdrawn lmmedlately and comblned readlly wlth other rl addenda to produce the deslred photothermographlc composltlon.
~'. 20 A variety of hydrophobic binders are useful in the described photothermographlc materials. The blnders that are useful include various colloids alone or in comblnatlon as vehicles and/or binding agents. The hydrophobic binders which are suitable include transparent or translucent materials. Useful binders lnclude polymers of alkylacrylates and methacrylates, acryllc acld, sulfoalkylacrylates or methacrylates, and those whlch have crosslinking sites that facllltate hardenlng or curlng. Other useful hydrophoblc blnders lnclude hlgh molecular welght materlals and reslns, such as poly(vlnyl butyral), cellulose acetate butyrate, poly(methyl methacrylate~, poly(styrene), poly(vlnyl chlorlde), chlorinated rubber, poly(lsobutylene), butadlene-styrene copolymers, vinyl chlorlde-vinyl acetate copolymers, copolymers of vinyl acetate, vinyl chloride and maleic anhydride and the like. It ls lmportant that the hydrophoblc blnder not adversely a~fect the sensitometric or other ~.
~.
55ti1 desired properties of the described photothermographic material. Poly(vinyl butyral) is especially useful.
This is available under the trade~e "BUTVAR" from The Monsanto Company, U.S.A.
A range of concentration of hydrophobic binder can be useful in the photothermographic silver halide materials according to the invention. Typically, the concentration of hydrophobic binder in a photothermographic silver halide com-position according to the invention is within the range of about 20 to about 65 mg/dm2. An optimum concentration of the described binder can vary depending upon such factors as the particular binder, other components of the photothermo-graphic material, coating conditions, desired image, processing temperature and conditions and the like.
If desired, a portion of the photographic silver halide in the photothermographic composition according to the invention can be prepared in situ in the photothermographic material. The photothermographic com-position, for example, can contain a portion of the photo-graphic silver halide that is prepared in or on one or more of the other components of the described photothermographic material rather than prepared separate from the described components and then admixed with them. Such a method of preparing silver halide in situ is described in, for example, U.S. Patent 3,457,075 of Morgan et al, issued July 22, 1969.
The described photothermographic composition com-prises an oxidation-reduction image-forming combination con-taining a long-chain fatty acid silver salt with a suitable reducing agent. The oxidation-reduction reaction resulting from this combination upon heating is believed to be catalyzed by the latent image silver from the photosensitive silver halide produced upon imagewise exposure of the photo-thermographic material followed by overall heating of the photothermographic material. The exact mechanism of image formation is not fully understood.
~!255~1 A variety of silver salts of long-chain fatty acids are useful in the photothermographic materials according to the lnvention. The term "lon~-chaln" as used hereln ls lntended to refer to a ratty acid containlng 12 to 30 carbon atoms and which is typically resistant to darkenlng upon exposure to light. Use~ul long-chain fatty acld sllver salts lnclude, for example, silver stearate, sllver behenate, sllver caprate, silver hydroxystearate, silver myrlstate and silver palmltate. A minor proportlon of another sllver salt oxidizing agent which is not a long-chain fatty acld sllver salt can be useful in comblnatlon wlth the sllver salt Or the long-chain fatty acld lf desired. Such silver salts which can be useful in combination with the descrlbed sllver salts of a long-chain fatty acid include, for example, ; 15 silver benzotriazole, silver imidazole, silver benzoate and ~ the like. Combinations of silver salts of long-chain fatty ; acids can be useful in the described photothermographlc materials if desired.
~, A variety of organic reducing agents are useful in the described photothermographic sllver hallde materlals accordlng to the lnvention. These are typically silver halide developing agents which produce the desired oxidation-reduction image-forming reactlon upon exposure and heating of the descrlbed photothermographic silver hallde material. Examples of useful reduclng agents lnclude polyhydroxybenzenes, such as hydroquinone and alkyl sub-stltuted hydroquinones; catechols and pyrogallol; phenylene-dlamlne developing agents; amlnophenol developlng agents;
ascorblc acld developlng agents, such as ascorblc acid and ascorbic acld ketals and other ascorblc acld derlvatives;
hydroxylamlne developlng agents; 3-pyrazolidone developlng agents such as l-phenyl-3-pyrazolldone and 4-methyl-4-hydroxymethyl-l-phenyl-3-pyrazolldone; hydroxytetronlc acld and hydroxytetronamide developlng agents; reductone developlng agents; bls-B-naphthol reducing agents; sulfon-amldophenol reduclng agents and the llke. Comblnatlons Or , ~".....
55t~1 organlc reduclng agents can be useful ln the described photothermographlc sllver hallde materlals. Sulfonamldo-phenol developlng agents, such as descrlbed ln Belglan Patent 802,519 lssued January 18, 1974, can be especlally useful ln the photothermographlc sllver hallde composltlon.
A range of concentratlon Or the organlc reduclng agent can be useful ln the descrlbed photothermographlc sllver hallde materlals. The concentratlon of organlc reduclng agent ls typically withln the range of about 5 mg/dm2 to about 20 mg/dm2, such as wlthln the range of about 10 to about 17 mg/dm2. The optlmum concentration of organlc reduclng agent wlll depend upon such factors as the particular long-chaln fatty acld, the deslred lmage, processin~
condltlons, the partlcular solvent mlxture, coating condltlons and the llke.
The order of addltion of the descrlbed components for preparlng the photothermographic compositlon before coating the composition onto a sultable support ls lmportant to obtain optimum photographic speed, contrast and maxlmum density. In an especlally useful method accordlng to the invention the low-gel silver halide emulsion ls added to an ultrasonlc mixing means through one lnlet and a solvent mixture containing toluene, up to about 10% by weight poly(vlnyl butyral) and benzyl alcohol ls added through another lnlet. The low-gel silver hallde ls dlspersed thoroughly ln thls environment by ultrasonlc waves. The resultlng product is then combined with the remainlng components of the deslred photothermographlc composition.
If the low-gel silver halide is not dispersed as described before addlng the other components, the sllver hallde gralns ln the composltlon have a tendency to clump together and preclpltate to the bottom of the contalner ln whlch the composltion is mlxed.
~, l~St~l ~13-A variety of mixing means are useful for preparing the descrlbed composltlons. However, the mlxlng means should be one whlch provldes very thorough mixing, such as an ultrasonlc mlxlng means. Other mlxlng means than ultrasonlc mixing means that can be useful are commerclally avallable - colloid mlll mixing means and dlspersator mixing means known in the photographlc art. A blender, such as a blender known under the trade name of "Waring" blender, does not produce the very thorough mixlng that ls desired in most cases.
It is desirable, ln some cases, to have what ls descrlbed as a tonlng agent, also known as an actlvator-; toning agent, in the photothermographlc materlal accordlng to the invention. Combinations of toning agents can often be useful. Typical toning agents lnclude, for e~ample, phthalimide, succlnlmlde, N-hydroxyphthallmide, N-hydroxy-1,8-naphthalimide, N-hydroxysuccinimide, 1-(2H)-phthalazinone and phthalazinone derivatlves.
Photothermographlc materials according to the invention can contain other addenda that are userul ln imaging. Suitable addenda in the descrlbed photothermo-graphlc materials include development modl~lers that functlon as speed-lncreasing compounds, hardeners, anti-static layers, plasticizers and lubricants, coating alds, brighteners, spectral sensitlzing dyes, absorbing and fllter dyes, matting agents and the like.
It is useful in certain cases to include a stabilizer in the described photothermographic material.
This can help in stabilizatlon of a developed lmage. Com-binations of stabillzers can be useful lf deslred. Typlcal stabillzers or stabilizer precursors include certaln halogen compounds, such as tetrabromobutane and 2-(tribromo-methylsulfonyl), benzothiazole, which provide improved post-processing stabllity and azothioethers and blocked azollne thlone stabllizer precursors.
The photothermographlc elements accordlng to the inventlon can comprlse a varlety Or supports which can 1~2S5~1 tolerate the processing temperatures useful in developing an image. Typical supports include cellulose ester, poly(vinyl acetal), poly(ethylene terephthalate), poly-carbonate and polyester film supports. Related film and resinous support materials, as well as paper, glass, metal and the like supports which can withstand the described processing temperatures are also useful. Typically a flexible support is most useful.
The photothermographic compositions can be coated on a suitable support by coating procedures known in the photographic art including dip coating, airknife coating, curtain coating or extrusion coating using hoppers. If desired, two or more layers can be coated simultaneously.
The described silver halide and oxidation-reduction image-forming combination can be in any suitable location in the photothermographic element according to the invention which produces the desired image. In some cases it can be desirable to include certain percentages of the described reducing agent, the silver salt oxidizing agent and/or other addenda in a protective layer or overcoat layer over the layer containing the other components of the element as described. The components, however, must be in a location which enables their desired interaction upon processing.
It is necessary that the photosensitive silver halide, as described, and other components of the imaging combination be "in reactive association" with each other in order to produce the desired image. The term "in reactive association", as employed herein, is intended to mean that the photosensitive silver halide and the image-forming combination are in a location with respect to each other which enables the desired processing and produces a useful image.
A useful embodiment of the invention is a photo-thermographic silver halide composition capable of being coated on a support comprising ~a~ an aqueous photosensitive - ~2S~til silver hallde emulsion contalnlng a gelatlno peptlzer wlth (b) an organic solvent mixture comprlslng a comblnatlon Or a benzyl alcohol photographlc speed-lncreasing solven~, such as benzyl alcohol, with toluene and up to 4~ by welght 5 poly(vinyl butyral), (c) a hydrophobic polymeric blnder conslsting essentially of poly(vinyl butyral) and (d) an oxidation-reduction image-rorming combination comprlslng (i) a silver salt or a long-chain fatty acld conslstlng essentially of silver behenate wlth (11) an organlc reducing 10 agent consisting essentially of a sulfonamldophenol. This composition can be coated on a suitable support to produce a photothermographic element according to the lnventlon.
Another embodiment of the inventlon is a method of preparing a photothermographlc element comprising coating the resulting 15 composition onto a suitable support to produce a photothermo-graphic element as desired.
A variety of imagewise exposure means are useful ; wlth the photothermographic materials according to the invention. The imaging means according to the lnvention 20 can be any suitable source of radiation to which the photo-thermographic material is sensitive. The imaging materials according to the invention are typically sensitive to the t ultraviolet and blue regions of the spectrum and exposure means which provide this radiation are preferred. Typically, 25 however, if a spectral sensitizing dye or combination of spectral sensitizing dyes are present in the photothermo-graphic material, exposure means using other ranges of the electromagnetic spectrum can be useful. Typically, a photo-thermographic material according to the invention is exposed 30 imagewise with a visible light source, such as a tungsten lamp. Other sources of radiation can be useful and include, for instance, lasers, electron beams, X-ray sources and the like. The photothermographic materials are typlcally exposed imagewise to produce a developable latent image.
:
llZ55til A visible image can be developed in the photo-thermographic material according to the invention withln a short time, such as within several seconds, merely by heating the photothermographic material to moderately elevated temperatures. For example, the exposed photothermo-graphic material can be heated to a temperature within the range of about 100C to about 200C, such as a temperature within the range of about 110C to about 140C. Heating is carried out until a desired image is developed, typically within about 2 to about 30 seconds, such as about 2 to about 10 seconds. Selection of an optimum processing time and temperature will depend upon such factors as the desired image, particular components of the photothermographic element, the particular latent image and the like.
A variety of means can be useful to produce the necessary heating of the described photothermographic material to develop the desired image. The heating means can be a simple hot plate, iron, roller, infrared heating means, hot air heating means or the like.
Processing according to the invention is typically carried out under ambient conditions of pressure and humidity. Pressures and humidity outside normal atmospheric conditions can be useful if desired; however, normal atmospheric conditions are preferred.
The following examples are included for a further understanding of the invention.
Example 1 This illustrates the invention.
A silver behenate/behenic acid dispersion (C) was prepared by blending the following components:
acetone 250 ml toluene 250 ml poly(vinyl butyral~ 30.3 g behenic acid 16.0 g 35 silver behenate 42.0 g ~55~jl A silver hallde gelatlno photosensltlve dispersion (Z) was prepared as follows: An aqueous solution of 10 3 molar lithium bromide was added to 0.02 mole of a 400 A silver bromoiodlde (6 mole % lodlde) gelatino emulsion (40 grams non-phthalated gelatin per silver mole) to produce a total weight of 200 grams. The resulting mixture was stlrred for 15 minutes at 40C and a pH of 6.1 with a pAg of 8.4. The emulsion was centrifuged for 20 minutes at 3000 rpm. The resulting supernatant was discarded and a 100 mg sample of the wet centrifuged silver halide emulsion was treated with ultrasonic waves for 30 seconds in the presence of 3 ml of a solvent mixture containing toluene (87 grams) and 4~ by weight poly(vinyl butyral) with 4 grams of benzyl alcohol.
Thls resultlng sllver hallde dlsperslon (Z) was combined with the following components:
acetone/toluene (1:9 parts 0.15 ml by volume) solution con-~ taining 0.01% by weight - 20 3-ethyl-2-thio-2,4-oxazolidinedione (speed-increasing addenda) acetone/toluene (1:9 parts 0.50 ml by volume) solution con-taining 0.01% by weight 3-ethyl-5-(3-ethyl-2-benzoxazolylideneethylidene)-- l-phenyl-2-thiohydantoin (sensitizing dye) silver behenate dispersion C 3.6 ml (described above) (oxidizing agent) The resulting composition was mixed by shaking for several mlnutes. The dispersion was combined with the following solutions and coated on an unsubbed poly(ethylene terephthalate) film support at a o.oo8 inch (8 mils) wet coatlng thlckness:
~'~
l~Z55~1 acetone~toluene (1:1 parts Q.50 ml by volume) solution con-taining 25% by weight 2,6-dichloro-4-benzenesulfon-amidophenol (reducing agent) toluene solution containing 2 drops siloxane surfactant (containing
2% by weight silicone AF-70, trademark of the General Electric Company) acetone solution containing 5% 0.30 ml by weight 2-(tribromomethyl-sulfonyl)benzothiazole (stabilizer) The resulting coating was dried at 48.9C for 5 minutes. This produced a photothermographic element according to the invention. The element was imagewise exposed to light through a 1.0 neutral density and a graduated density step wedge to produce a developable latent image in the photothermographic element. The resulting image was developed by heating the photothermo-graphic element for 5 seconds at 140C. A high contrast developed image was produced. The image had a maximum density above 3.8 and a minimum density of 0.12.
The resulting photothermographic element was free from mottle and exhibited a smooth surface.
The resulting photothermographic element and its sensitometric properties compared favorably with a similarly prepared photothermographic element that con-tained silver halide having a similar grain size but which, in the absence of gelatin, had been formed in a poly(vinyl butyral) composition with an acetone solvent in place of the combination of benzyl alcohol and toluene.
Example 2 This illustrates use of a phthalated gelatin peptized silver halide emulsion containing less than 9 grams of phthalated gelatin per mole of silver in a non-aqueous photothermographic material according to the invention.
55Sà~
A gelatino silver halide emulsion was prepared by adding following Solutions B and C simultaneously to following Solution A at the rate of 6.3 milllliters per minute.
Solution A
Phthalated gelatin 9 g Distilled water 783 ml Temperature 35C
pH 5.0 VAg + 60 mv Solution B
NaBr 133.9 g KI 4.6 g Distilled water 152 ml Room temperature (about 20C) Total Vol. 186 ml Solution C
AgN03 170 g Distilled water 109 ml Room temperature (about 20C) Total Vol. 143 ml After 50 seconds, Solution A was adjusted to a VAg + 110 mv with a bromide ion solution. The total precipitation time was approximately 22 minutes, i.e.
until Solution C was completely added. Then Solution B
25 addition was stopped. The final composition had a pH of 5.50 and a pAg of 8.41. The temperature of the reaction vessel was increased to 40C and the pH was adjusted to
The resulting photothermographic element was free from mottle and exhibited a smooth surface.
The resulting photothermographic element and its sensitometric properties compared favorably with a similarly prepared photothermographic element that con-tained silver halide having a similar grain size but which, in the absence of gelatin, had been formed in a poly(vinyl butyral) composition with an acetone solvent in place of the combination of benzyl alcohol and toluene.
Example 2 This illustrates use of a phthalated gelatin peptized silver halide emulsion containing less than 9 grams of phthalated gelatin per mole of silver in a non-aqueous photothermographic material according to the invention.
55Sà~
A gelatino silver halide emulsion was prepared by adding following Solutions B and C simultaneously to following Solution A at the rate of 6.3 milllliters per minute.
Solution A
Phthalated gelatin 9 g Distilled water 783 ml Temperature 35C
pH 5.0 VAg + 60 mv Solution B
NaBr 133.9 g KI 4.6 g Distilled water 152 ml Room temperature (about 20C) Total Vol. 186 ml Solution C
AgN03 170 g Distilled water 109 ml Room temperature (about 20C) Total Vol. 143 ml After 50 seconds, Solution A was adjusted to a VAg + 110 mv with a bromide ion solution. The total precipitation time was approximately 22 minutes, i.e.
until Solution C was completely added. Then Solution B
25 addition was stopped. The final composition had a pH of 5.50 and a pAg of 8.41. The temperature of the reaction vessel was increased to 40C and the pH was adjusted to
3.5 with 1.5 N nitric acid. The supernatant was decanted and the coagulum was redispersed by adding 10 3 M lithium 3 bromide solution to make a final weight of 1300 grams (pAg 7.70) and ad~usting the composition to a pH of 6.50 with 2.0 M lithium hydroxide. This procedure was repeated twice and after removal of the final supernatant the con-centrated coagulum (about 500 grams per silver mole) was 1~ ~SS~I
adjusted to pH 6.5 and a pAg of 8.3 with vigorous stirring at 40C ~or 30 minutes to insure complete dispersal and ionic equilibrium before chill setting for storage. The resulting silver halide emulsion at 40C was mixed with 3 ml of a solvent mixture containing toluene (87 grams), 4~ by weight poly(vinyl butyral) and benzyl alcohol (4 grams) using an ultrasonic mixing means. The resulting composition was then combined with other components as described in Example 1 to provide a photothermographic element according to the invention.
The resultlng photothermographlc element was imagewise exposed to light to provlde a developable latent image in the element. The image was developed by heating the element at 125C for 5 seconds. The developed image had a maximum density of 1.64 and a minimum density of 0.26.
Example 3 The procedure described in Example 2 was repeated ; with the exception that one of the compounds designated as A - G was used as the solvent at 0.90 mole per mole of silver halide in place of the described concentration of benzyl alcohol.
Compound Name A benzyl alcohol B DL-~-methylbenzyl alcohol 25 C o-phenoxybenzyl alcohol D m-(trifluoromethyl)benzyl alcohol E p-bromobenzyl alcohol F o-iodobenzyl alcohol G Sucrose The photothermographic element containing the described compounds was prepared with the silver halide as described in Example 2. The resulting photothermographic elements were each imagewise exposed for one-eighth second to a mercury light source through a graduated density step wedge to produce a developable latent image in the element.
The image was developed by heating the element at 125C
for 5 seconds in each instance. The sensitometric results ~or each of the compounds noted is glven ln following Table I:
,w. , l~Z55C~1 X 3 r-- O ~L:) O ~1 ~D 3 3 O~ 3 0 r-l .. . . . ,~ .
E~
~D O t-- 0 3 ~I r I O
~3 O O O O O O O
o C) O ~ ~D O O CO
3 ~ ~D ~ ~:
.
O ~ ~ ~ O ~ O O
H t~
a) ~ O
Q~ ~1 .
~a) o E~ a~ u Q
a~ o ~ ~ ~ 3 0 Il~
~ o a~ co O ~1 ~I
,1 ~ ~ ~ ~
td a~
~:
a :~
o 2;
o c> a) c) ~
~ ~ ~ *
5~1 The data in Table I illustrates that Compounds B, C and D produce results similar to Compound A (benzyl alcohol). That is, the compounds produce increased relative speed and maximum density compared to the photo-thermographic element containing no benzyl alcohol.
Compounds E, F and G produced detrimental relative speed results. Enhanced contrast was observed in photographic elements containing Compounds B and C.
Example 4 The procedure described in Example 2 was repeated with the exception that one of the compounds designated 4A, 4H, 4I and 4J was used as the solvent at 0.90 mole per mole of silver halide in place of the described concentration of benzyl alcohol.
15Compound Name 4A benzyl alcohol 4H _-methylbenzyl alcohol 4I _-methoxybenzyl alcohol 4J 2-phenoxyethanol The resulting coatings were imagewise exposed for 10 3 seconds to a tungsten light source through a graduated density step wedge to produce a developable latent image in the exposed photothermographic element. The imagewise exposed photothermographic element was processed by heating the element at 125C for 5 seconds. A
developed image was produced in each element. The sensitometric results were as follows:
1~255~ 1 ~C O O
~D
H ~J N
~ ~ a~
rl ~ OOOOO
t~ O O O O
~_ O ~1 ~I r-l (~
H ~1 H
a D
E~ ~ a) ~n o a)o o~ ~ ~ o O ~ ~ U~ ~
r~ J O
td ~ J~
P;
*
~ a~ ~
O ~: C X H 1~ ~) E~ ~z; a) O ~;
V *
,.
Improvement in photographic speed, contrast, and maximum density with reduced minimum density was observed when comparing the results for Compounds 4A, 4H, 4I and 4J with the control. The use of benzyl alcohol and its derivatives in the described photothermographic material also provldes a reduction in haze in the photothermographic layer of the element. The photothermographic element in each instance after processing is free of haze.
The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.
adjusted to pH 6.5 and a pAg of 8.3 with vigorous stirring at 40C ~or 30 minutes to insure complete dispersal and ionic equilibrium before chill setting for storage. The resulting silver halide emulsion at 40C was mixed with 3 ml of a solvent mixture containing toluene (87 grams), 4~ by weight poly(vinyl butyral) and benzyl alcohol (4 grams) using an ultrasonic mixing means. The resulting composition was then combined with other components as described in Example 1 to provide a photothermographic element according to the invention.
The resultlng photothermographlc element was imagewise exposed to light to provlde a developable latent image in the element. The image was developed by heating the element at 125C for 5 seconds. The developed image had a maximum density of 1.64 and a minimum density of 0.26.
Example 3 The procedure described in Example 2 was repeated ; with the exception that one of the compounds designated as A - G was used as the solvent at 0.90 mole per mole of silver halide in place of the described concentration of benzyl alcohol.
Compound Name A benzyl alcohol B DL-~-methylbenzyl alcohol 25 C o-phenoxybenzyl alcohol D m-(trifluoromethyl)benzyl alcohol E p-bromobenzyl alcohol F o-iodobenzyl alcohol G Sucrose The photothermographic element containing the described compounds was prepared with the silver halide as described in Example 2. The resulting photothermographic elements were each imagewise exposed for one-eighth second to a mercury light source through a graduated density step wedge to produce a developable latent image in the element.
The image was developed by heating the element at 125C
for 5 seconds in each instance. The sensitometric results ~or each of the compounds noted is glven ln following Table I:
,w. , l~Z55C~1 X 3 r-- O ~L:) O ~1 ~D 3 3 O~ 3 0 r-l .. . . . ,~ .
E~
~D O t-- 0 3 ~I r I O
~3 O O O O O O O
o C) O ~ ~D O O CO
3 ~ ~D ~ ~:
.
O ~ ~ ~ O ~ O O
H t~
a) ~ O
Q~ ~1 .
~a) o E~ a~ u Q
a~ o ~ ~ ~ 3 0 Il~
~ o a~ co O ~1 ~I
,1 ~ ~ ~ ~
td a~
~:
a :~
o 2;
o c> a) c) ~
~ ~ ~ *
5~1 The data in Table I illustrates that Compounds B, C and D produce results similar to Compound A (benzyl alcohol). That is, the compounds produce increased relative speed and maximum density compared to the photo-thermographic element containing no benzyl alcohol.
Compounds E, F and G produced detrimental relative speed results. Enhanced contrast was observed in photographic elements containing Compounds B and C.
Example 4 The procedure described in Example 2 was repeated with the exception that one of the compounds designated 4A, 4H, 4I and 4J was used as the solvent at 0.90 mole per mole of silver halide in place of the described concentration of benzyl alcohol.
15Compound Name 4A benzyl alcohol 4H _-methylbenzyl alcohol 4I _-methoxybenzyl alcohol 4J 2-phenoxyethanol The resulting coatings were imagewise exposed for 10 3 seconds to a tungsten light source through a graduated density step wedge to produce a developable latent image in the exposed photothermographic element. The imagewise exposed photothermographic element was processed by heating the element at 125C for 5 seconds. A
developed image was produced in each element. The sensitometric results were as follows:
1~255~ 1 ~C O O
~D
H ~J N
~ ~ a~
rl ~ OOOOO
t~ O O O O
~_ O ~1 ~I r-l (~
H ~1 H
a D
E~ ~ a) ~n o a)o o~ ~ ~ o O ~ ~ U~ ~
r~ J O
td ~ J~
P;
*
~ a~ ~
O ~: C X H 1~ ~) E~ ~z; a) O ~;
V *
,.
Improvement in photographic speed, contrast, and maximum density with reduced minimum density was observed when comparing the results for Compounds 4A, 4H, 4I and 4J with the control. The use of benzyl alcohol and its derivatives in the described photothermographic material also provldes a reduction in haze in the photothermographic layer of the element. The photothermographic element in each instance after processing is free of haze.
The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.
Claims (23)
1. In a photothermographic silver halide com-position capable of being coated on a support comprising a hydrophilic photosensitive silver halide emulsion containing a gelatino peptizer with an organic solvent mixture, a hydrophobic binder and an oxidation-reduction image-forming composition comprising (i) a silver salt of a long-chain fatty acid with (ii) an organic reducing agent for said silver salt of a long-chain fatty acid, the improvement wherein said composition comprises, as said solvent mixture, a combination of (A) an alcohol photographic speed-increasing solvent which is a compound selected from the group consisting of benzyl alcohol photo-graphic speed-increasing solvents and 2-phenoxyethanol photographic speed-increasing solvents with (B) an aromatic hydrocarbon solvent that is compatible with said alcohol solvent.
2. A photothermographic silver halide com-position as in Claim 1 wherein the concentration of the gelatino peptizer is within the range of about 5 g to about 20 g of gelatin per mole of silver in said silver halide emulsion.
3. A photothermographic silver halide composition as in Claim 1 wherein said alcohol solvent consists essentially of 2-phenoxyethanol.
4. A photothermographic silver halide com-position as in Claim 1 wherein said alcohol solvent consists essentially of benzyl alcohol.
5. A photothermographic silver halide composition as in Claim 1 wherein said alcohol solvent consists essentially of DL-.alpha.-methylbenzyl alcohol.
6. A photothermographic silver halide composition as in Claim 1 wherein said alcohol solvent consists essentially of m-(trirluoromethyl)benzyl alcohol.
7. A photothermographic silver halide composition as in Claim 1 wherein said hydrocarbon solvent consists essentially of toluene.
8. A photothermographic silver halide composition as in Claim 1 comprising a concentration of said alcohol solvent that is within the range of about 0.25 mole to about 2.0 moles of said alcohol solvent per mole of photosensitive silver halide in said emulsion; and, the ratio by volume of said alcohol solvent to said hydrocarbon solvent is within the range of about 1:50 to 1:200.
9. A photothermographic silver halide composition as in Claim 1 wherein said solvent mixture also comprises up to 10% by weight poly(vinyl butyral).
10. In a photothermographic silver halide com-position capable of being coated on a support comprising an aqueous photosensitive silver halide emulsion containing a gelatino peptizer with an organic solvent mixture, a hydrophobic polymeric binder consisting essentially of poly(vinyl butyral) and an oxidation-reduction image-forming combination com-prising (1) a silver salt of a long-chain fatty acid con-sisting essentially of silver behenate with an organic reducing agent consisting essentially of a sulfonamido-phenol reducing agent for said silver salt of a long-chain fatty acid, the improvement wherein said composition comprises, as said solvent mixture, a combination of 2-phenoxyethanol with toluene and up to 10% by weight poly(vinyl butyral).
11. In a photothermographic silver halide com-position capable of being coated on a support comprising (I) an aqueous photosensitive silver halide emulsion containing a gelatino peptizer with (II) comprising an organic solvent mixture, (a) a hydrophobic polymeric binder consisting essentially of poly(vinyl butyral) and (b) an oxidation-reduction image-forming combination comprising (i) a silver salt of a long-chain fatty acid consisting essentially of silver behenate with (ii) an organic reducing agent con-sisting essentially of a sulfonamidophenol reducing agent for said silver salt of a long-chain fatty acid, the improvement wherein said composition comprises, as said solvent mixture, a combination of benzyl alcohol with toluene and up to 10% by weight poly(vinyl butyral).
12. In a method of preparing a photothermographic element comprising very thoroughly mixing (I) a hydrophilic photosensitive silver halide emulsion comprising a gelatino peptizer with (II) an organic solvent mixture and then very thoroughly mixing the resulting product with (III) comprising (a) a hydrophobic binder and (b) an oxidation-reduction image-forming composition comprising (i) a silver salt of a long-chain fatty acid with (ii) an organic reducing agent for said silver salt of a long-chain fatty acid, and coat-ing the resulting composition onto a support, the improvement wherein said method comprises said mixing of (I) with (II) wherein (II) comprises (A) an alcohol photographic speed-increasing solvent with (B) an aromatic hydrocarbon solvent that is compatible with said alcohol solvent and (C) 0 to 10% by weight of (II) of a hydro-phobic binder.
13. A method as in Claim 12 wherein said alcohol solvent consists essentially of benzyl alcohol.
14. A method as in Claim 12 wherein said alcohol solvent consists essentially of DL-.alpha.-methylbenzyl alcohol.
15. In a method as in Claim 12 wherein said alcohol solvent consists essentially of m-(trifluoromethyl)benzyl alcohol.
16. A method as in Claim 12 wherein said alcohol solvent consists essentially of 2-phenoxyethanol.
17. In a method as in Claim 12 wherein said hydrocarbon solvent consists essentially of toluene.
18. A method as in Claim 12 wherein the concen-tration of said alcohol solvent is within the range of about 0.25 mole to about 2.0 moles of said alcohol solvent per mole of photosensitive silver halide; and, the ratio by volume of said alcohol solvent to said hydrocarbon solvent prior to said coating is within the range of about 1:50 to 1:200.
19. In a method of preparing a photothermographic element comprising ultrasonic wave mixing (I) a hydrophilic photosensitive silver halide emulsion comprising a gelatino peptizer with (II) an organic solvent mixture and then ultrasonic wave mixing the resulting product with (III) com-prising (a) poly(vinyl butyral) binder and (b) an oxidation-reduction image-forming composition comprising (i) silver behenate with (ii) a sulfonamidophenol reducing agent for said silver behenate, and coating the resulting composi-tion onto a support, the improvement wherein said method comprises said mixing of (I) with (II) wherein (II) comprises (A) benzyl alcohol with (B) toluene and (C) 0 to 10% by weight poly-(vinyl butyral).
20. In a method of preparing a photothermographic element comprising ultrasonic wave mixing (I) a hydrophilic photosensitive silver halide emulsion comprising a gelatino peptizer with (II) an organic solvent mixture and then ultrasonic wave mixing the resulting product with (III) com-prising (a) poly(vinyl butyral) binder and (b) an oxidation-reduction image-forming composition comprising (i) silver behenate with (ii) a sulfonamidophenol reducing agent for said silver behenate and coating the resulting composition onto a support, the improvement wherein said method comprises said mixing of (I) with (II) wherein (II) comprises (A) 2-phen-oxy-ethanol with (B) toluene and (C) 0 to 10% by weight poly(vinyl butyral).
21. A photothermographic element prepared by the process defined in Claim 12.
22. A photothermographic element prepared by the process defined in Claim 19.
23. A photothermographic element prepared by the process defined in Claim 20.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US95286378A | 1978-10-19 | 1978-10-19 | |
| US952,863 | 1978-10-19 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1125561A true CA1125561A (en) | 1982-06-15 |
Family
ID=25493299
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA319,279A Expired CA1125561A (en) | 1978-10-19 | 1979-01-08 | Photothermographic composition including a mixture containing benzyl alcohol or 2-phenoxyethanol speed-increasing solvent and an aromatic hydrocarbon solvent |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPS5555333A (en) |
| CA (1) | CA1125561A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57169782A (en) * | 1981-04-11 | 1982-10-19 | Dainippon Printing Co Ltd | Production for hologram |
-
1979
- 1979-01-08 CA CA319,279A patent/CA1125561A/en not_active Expired
- 1979-10-19 JP JP13427079A patent/JPS5555333A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6255649B2 (en) | 1987-11-20 |
| JPS5555333A (en) | 1980-04-23 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US3874946A (en) | Photothermographic element, composition and process | |
| US6143488A (en) | Photothermographic recording material coatable from an aqueous medium | |
| US6140037A (en) | Photothermographic material and method for making | |
| JP2690351B2 (en) | Thermoworkable element comprising a backing layer | |
| US4435499A (en) | Photothermographic silver halide material and process | |
| JPH0426097B2 (en) | ||
| US6132949A (en) | Photothermographic material | |
| US6093529A (en) | Imaging materials | |
| US4264725A (en) | Photothermographic composition and process | |
| EP0969313A1 (en) | Photothermographic element having desired color | |
| US4459350A (en) | Photothermographic material and processing comprising a substituted triazine | |
| EP0791187A1 (en) | Photographic element comprising antistatic layer and process for making an element having antistatic properties | |
| US6132948A (en) | Photothermographic material | |
| US6274297B1 (en) | Photothermographic recording material with in-situ and ex-situ photosensitive silver halide and a substantially light-insensitive organic salt | |
| US5998127A (en) | Photothermographic materials | |
| CA1125561A (en) | Photothermographic composition including a mixture containing benzyl alcohol or 2-phenoxyethanol speed-increasing solvent and an aromatic hydrocarbon solvent | |
| JP2656973B2 (en) | Method of manufacturing a photothermographic element | |
| US3761273A (en) | Process for preparing radiation sensitive materials | |
| CA1116917A (en) | Covering power photothermographic material containing a hydrazino thiourea nucleating agent | |
| US5965348A (en) | Thermographic material | |
| JP2002189269A (en) | Thermally developable imaging material containing surface barrier layer | |
| EP0922995B1 (en) | Photothermographic recording material with in-situ and ex-situ photosensitive silver halide and a substantially light-insensitive organic silver salt | |
| JPH08297345A (en) | Medical heat developable photosensitive material sensitive to infrared laser beam | |
| JP3860043B2 (en) | Method for packaging photothermographic material | |
| JP3626307B2 (en) | Photothermographic material |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |