US3679421A - Azo dye-forming system including a boric acid ester - Google Patents

Abstract

THE RESISTANCE TO PREMATURE COUPLING AND THE DEVELOPMENT RATE OF TWO-COMPONENT DIAZOTYPE COMPOSITIONS I.E., AT LEAST ONE DIAZONIUM SALT AND AT LEAST ONE COUPLER COMPOUND) ARE ADVANTAGEOUSLY INCREASED BY THE INCLUSION THEREIN OF A BORIC ACID ESTER.

Description

25, 1972 G. P. KASPER 3,679,421

AZO DYE-FORMING SYSTEM INCLUDING A BORIC ACID ESTER Filed Aug. 26, 1969 D/AZOTYPE COMPOSITION INCLUDING A BOP/C ACID ESTER OIA Z0 TYPE 6 OMPOS/ T/ON WITHOUT A BOP/C ACID E 5 T E I? "/0 COMPLETION OF DEVELOPMENT 0 I l l 1 DEVELOPMENT TIME SECONDS GEORGE P KASPEE INVENTOR.

BY Mk/k ATTORNEY United States Patent US. CI. 96-91 R 7 Claims ABSTRACT OF THE DISCLOSURE The resistance to premature coupling and the development rate of two-component diazotype compositions (i.e., at least one diazonium salt and at least one coupler compound) are advantageously increased by the inclusion therein of a boric acid ester.

This invention is related to photography and is concerned particularly with novel, two-component diazotype compositions which provide increased resistance to premature coupling upon storage and permit an increased development rate.

Two-component diazotype reproduction media normally comprise a polymeric matrix containing at least one diazonium salt and at least one coupler compound which reacts with the diazonium salt, typically in an alkaline medium, to form an azo dye. In addition, there can be present various other additives, such as ultraviolet absor bers, stabilizers to prevent premature coupling of the diazonium salt and the coupler as well as additional known addenda. These diazotype compositions or azo dye-forming systems have been employed generally as duplicating media. Their use typically involves an imagewise exposure to activating radiation, e.g., light, through an original, whereby the transmitted light decomposes the diazonium salt. After exposure the iilm is usually treated with a basic medium, such as aqueous ammonia vapor, to promote coupling of the undecomposed diazonium salt and coupler compound, thereby forming an azo dye in the unexposed areas to provide a positive image corresponding to that of the original.

Two disadvantages heretofore associated with diazotype reproduction media are that such media tend towards instability causing undesirable pre-coupling upon storage, and that the processing times for image development are often unduly long. (It is known that certain organic acids contained in the media prevent pre-coupling of the diazonium salt and the coupler compound before development of the desired image. Likewise, it is known that certain addenda compounds accelerate the development rate. However, many modifying chemical addenda can deleteriously affect photographic properties. Also, it has been necessary heretofore to incorporate at least two distinct compounds to promote storage stability and to accelerate development rate of a diazotype composition.

Accordingly, it is an object of this invention to provide a new light-sensitive azo dye-forming system.

Another object of the present invention is to provide a novel light-sensitive azo dye-forming system which exhibits both an increased resistance to premature coupling and an increased development rate.

Still an additional object of the instant invention is to provide a new light-sensitive azo dye-forming system containing a boric acid ester to promote increased resistance to premature coupling and an increased develop ment rate.

Yet another object of the present invention is to provide a novel two-component diazotype composition containing a boric acid ester both to inhibit premature coupling and to promote rapid development.

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These and other objects of the present invention will become increasingly apparent from a reading of the following specification and appended claims.

The objects of this invention are accomplished with a diazotype composition which is useful as an image reproduction medium and which includes at least one lightsensitive diazonium salt, at least one coupler compound which can react with the diazonium salt to form an azo dye, as a combined precoupling inhibitor-development accelerator, at least one boric acid ester.

The boric acid esters used in the present diazonium compositions include the esterification products of boric acid and at least one hydroxylated organic compound such as an alcohol which is advantageously an aliphatic or aromatic monoor polyhydroxylic compound with monoand dihydroxy alcohols and glycols being favored. The boric acid esters useful herein can be desirably substituted, but it is preferred that they are substituted with other than highly basic substituents such as alkaline nitrogen-containing radicals, so as to preserve the advantageous acidic character of the diazotype composition prior to the desired time of image development, thereby heightening the precoupling restraint promoted by the subject boric acid esters.

Especially advantageous boric acid esters utilized herein are boric acid triesters of monohydn'c alcohols. Exemplary triesters include those having alkyl ester groups such as cycloalkyl and aliphatic alkyl groups including substituted aliphatic alkyl groups such as aralkyl groups as well as those having aryl ester groups. The ester groups attached to any boric acid molecule can be the same or different and can be composed of various substituent ester groups of the types mentioned immediately hereinabove. Especially useful ester groups include cycloalkyl radicals having from 4 to 6 carbon atoms in the ring nucleus, aliphatic alkyl radicals having from .1 to 8 carbon atoms in an alkyl chain which can be substituted with radicals including carbon atoms additional to those of the 1 to 8 carbon aliphatic alkyl chain (e.g. aralkyl radicals) and aryl radicals such as phenyl or n'aphthyl radicals. It is understood that the noted cycloalkyl, aliphatic alkyl and aryl ester group radicals are joined to the boric acid moiety through an oxygen linkage.

Preferred boric acid esters include such compounds as:

a trimethyl boric acid ester,

a dimethylethyl boric acid ester,

a triethyl boric acid ester,

a tripropyl boric acid ester,

a triphenyl boric acid ester,

3. tri(p-chlorophenyl) boric acid ester, a trinaphthyl boric acid ester,

a tricyclohexyl boric acid ester,

a tri(p-tolyl) boric acid ester, and

a triphenethyl boric acid ester.

The boric acid esters which are useful in this invention are advantageously incorporated into diazotype compositions in an amount up to 25 parts by weight per parts by weight of polymeric matrix and preferably between about 5 and 10 parts by weight per 100 parts by weight of polymeric matrix.

The diazotype compositions utilized herein typically include a diazonium salt and at least one coupler compound which can react with the diazonium salt to form an azo dye. Advantageous diazonium salts include benzene diazonium salts such as those having the formula:

wherein M is either:

(1) a hydrogen atom, (2) a halogen atom, (3) an aryl radical, (4) an amino radical including substituted amino radicals which can be cyclic radicals including the amino nitrogen atom and other hetero atoms such as oxygen, sulfur, nitrogen, etc., (5) a rnercapto radical, or (6) an alkyl or aryl thioether radical, and

acid anion.

These compounds can also be substituted on one or more of the nuclear benzene carbons with, for example, at least one of either a halogen atom, an aliphatic alkyl radical, an alkoxy radical, an acyl radical, a carbamyl radical, a carboxyl radical or a nitro radical. Aliphatic alkyl radicals are defined herein to include straight and branched chain alkyl radicals having from 1 to 8 carbon atoms such as methyl, ethyl, isopropyl, tertbutyl, n-amy], octyl and the like.

Particularly useful diazonium salts include p-aminobenzenediazonium salts having the formula as described above wherein M is either an amino radical including substituted amino radicals or a thioether radical such as described above, and wherein the benzene nucleus is unsubstituted or substituted in at least one of the 2-position and the 5-position with either an aliphatic alkyl radical or an alkoxy radical. This class of useful diazonium salts can be represented by the formula:

wherein:

(1) D is either a sulfur atom or a radical having the formula NR (2) R when taken alone, is either a hydrogen atom when D is NR or a lower aliphatic alkyl radical, a lower alkoxy radical, an acyl radical having the formula wherein T is either an aryl radical or an alkyl radical as described elsewhere herein, or a phenyl radical when D is either a sulfur atom or NR,

(3) R, when taken alone, is either a hydrogen atom, a

lower alkyl radical or a lower alkoxy radical,

(4) R and R when taken together, complete a divalent radical having the formula:

Preferred p-aminobenzene diazonium salts include substituted aminobenzene diazonium salts having the formula:

4 wherein:

( 1) each of R and R, when taken alone, is a lower alkyl radical,

(2) R and R when taken together, are the number of The most preferred benzene diazonium salts are the fluoroborate salts wherein:

(1) R and R are alkoxy radicals when R and R complete a morpholino radical, and

(2) R and R are each a hydrogen atom when R and R are each a lower alkyl radical.

Illustrative of the subject diazonium salts are such compounds as the salts of 1-diazo-2,S-dimethoxybenzene; l-diazo-2,5-diethoxybenzene; l-diazo-4-chloro-2,S-diethoxybenzene; 4idiazo-2,5-dimethoxybiphenyl; 4-diazo-2,5,4'-triethoxybiphenyl; 1-diazo-4-dimethylaminobenzene; l-diazo-4-(diethoxyamino)benzene; 1-djazo-4- [bis (hydroxypropyl)amino1benzene; l-diazol(N-methyl-N-allylamino)benzene; 1-diazo-4-(diamy1amino)benzene; l-diazo-4-(oxazolidino)benzene; 1-diazo-4-'(cyclohexylamino)benzene; l-diazo-4-(9-carbaz1olyl)benzene; 1-diazo-4.-(dihydroxyethylarnino)-3-methylbenzene; 1-diazo-4-dimethylamino-3-methylbenzene; 1-diazo-2-methyl-4-(N-methyl-N-hydroxypropylamino) benzene; 1-diaZo-4-dimethylamino-3-ethoxybenzene; 1-diazo-4-diethylamino-3-chlorobenzene; 1-diazo-2-carboxy-4-dimethylaminobenzene; 1-diazo-3- (2-hydroxyethoxy) -4-pyrrolidinobenzene; 1-diazo-2,5-diethoxy-4 acetoxyaminobenzene; 1-diazo-4-methylamino-3-ethoxy-6-chlorobenzene; 1-diazo-2,5-dichloro-4- benzylaminobenzene; 1-diazo-4-phenylaminobenzene; l-diazo-4-morpholinobenzene; 1-diazo-4-morpholino-3-methoxybenzene; 1-diazo-4-morpholino-2,S-dimethoxybenzene; 1-diazo-4-morpholino-2-ethoxy-S-methoxybenzene; 1-diazo-4-morpholino-2,S-dibutoxybenzene; 1-diazo-2,S-diethoxy-4-benzoylaminobenzene; 1-diazo-2,5-dibutoxy-4-benzoylaminobenzene; l-diazo-4-ethylmercapto-2,5-diethoxybenzene; 1-diazo-4-tolylmencapto-2,5-diethoxybenzene and the like,

as well as mixtures thereof.

Azo dye couplers which can be reacted with the diazonium salt to form an azo dye include a wide variety of chemical species such as those disclosed by Kosar, Light-Sensitive Systems, John Wiley & Sons, Inc., New York 1965), pp. 220-240. Phenolic couplers are preferred, however, with particularly preferred classes including:

(1) As blue couplers, 2-hydroxy-3-naphthanilides having the formula:

wherein R is a phenyl radical, and preferably a phenyl radical substituted with at least one of either a lower alkyl radical or a lower alkoxy radical or a halogen atom;

(2) As blue couplers, ortho naphthalenediols,

(3) As yellow couplers, l-hydroxy-Z-naphthamides having the formula:

(III

wherein:

NH 0 R wherein R is either an alkyl radical or an alkoxy radical and R is an aliphatic alkyl radical, an aryl radical, an aralkyl radical or an aralkoxy radical.

Illustrative of the subject couplers are such compounds as for example,

2-hydroxy-3-naphthanilide; 2-hydroxy-2-methyl-3-naphthanilide; Z-hydroxy-Z,2'-dimethoxy-5-chloro-3-naphthanilide; 2-hydroxy-2-dimethoxy-3-naphthanilide; 2-hydroxy-2',5-dimethoxy-4'-chloro-3-naphthanilide; 2-hydroxy-1'-naphthyl-3-naphthanilide; Z-hydroxy- '-naphthyl-3-naphthanilide; 2-hydroxy-4'-chloro-3-naphthanilide; 2-hydroxy-3-naphthanilide; 2-hydroxy-2',5'-dimethoxy-3-naphthanilide; 2-hydroxy-2',4'-dimethyl-B-naphthanilide; 2,3-naphthalene diol; l-hydroxy-Z-naphthamide; N-methyl-l-hydroxy-Z-naphthamide; N-butyl-l-hydroxy-Z-naphthamide; N-octadecyl-l-hydroxy-Z-naphthamide; N-phenyl-l-hydroxy-Z-naphthamide; N-methyl-N-phenyl-l-hydroxy-Z-naphthamide; N-(Z-tetradecyloxyphenyl)-1-hydroxy-2-naphthamide; N-[4(2,4-di-tert-amylphenoxy)butyl]-l-hydroxy-2- naphthamide; l-hydroxy-Z-naphthopiperidide; N-(3,5-dicarboxyphenyl)-N-ethyl-l-hydroxy-2-naphthamide; N,N-dibenzyl-l-hydroxy-2-naphthamide; N-(Z-chlorophenyl)-l-hydroxy-2-naphthamide; N-(4-methoxyphenyl)-l-hydroxy-2-naphthamide; 1-hydroxy-2-naphthopiperidide; l,3-bis( l-hydroxy-2-naphthamidobenzene) Z-acetamido-S-methylphenol; 2-acetamido-5-pentadecylphenyl; Z-butyramido-S-methylphenol; 2-(2,4di-tert-amylphenoxyacetamido)-5-methy1phenol; Z-benzamido-S-methylphenol and the like, as well as mixtures thereof.

In addition to the various alkyl, alkoxy and aryl radicals described herein, it is noted that lower aliphatic alkyl and alkoxy radicals are deemed to refer to aliphatic alkyl and alkoxy radicals having from 1 to 4 carbon atoms such as methyl, ethyl, propyl, isopropyl, isobutyl, tert-butyl and like alkyl radicals as well as alkoxy radicals such as methoxy, ethoxy, propoxy, tert-butoxy and the like.

For ease of coating and stability of the coated layer, the diazotype composition is generally dispersed in a polymeric matrix such as those described hereinbelow, conventionally in an amount of from about 20 to about 40 parts by weight per parts of matrix polymer.

In addition to the dye-forming components and boric acid esters of this invention, the diazotype composition can contain and usually does contain other additives such as ultraviolet absorbers, stabilizers and the like to advantageously modify its photographic and chemical properties. A preferred class of additives includes the known acid stabilizers which operate to prevent premature coupling of the diazonium salt and coupler compound. These acid stabilizers include organic acids such as S-sulfosalicylic acid and the like. In general, an organic acid stabilizer is preferably present in all of the diazotype reproduction media of this invention, with the amount normally varying from about 1 part to about 6, and preferably from about 2 to about 5 parts by weight per 100 parts of polymeric matrix. Additionally, metal salts such as zinc chloride can also be present as a development accelerator or dye brightener, generally in an amount of from about 0.5 to about 1.5 parts by weight per 100 parts of matrix polymer.

Another, and especially desirable, class of additives for diazotype compositions comprises hindered phenols containing in the 2-position either an alkyl or a cycloalkyl radical and in the 4-position an alkyl radical, an alkoxy radical, a hydroxyl radical or a thioether radical, which with the hindered phenolic moiety completes a hindered bisthiophenol and more generally a symmetrical bisthiophenol. These hindered phenols restrain fading of the developed azo dye image. Such advantageous hindered phenols are described in detail in the copending US. patent application Ser. No. 663,470, filed July 31, 1967, now Patent No. 3,591,381.

The diazotype compositions, including all supplemental addenda, are typically carried in a film-forming hydrophobic polymeric matrix or hinder when preparing photographic elements, both for ease of coating and physical stability of the resultant light-sensitive layer. Advantageous matrix polymers include a wide variety of polymeric substances such as, for example, cellulosic ethers such as ethyl cellulose, butyl cellulose as well as cellulose esters such as cellulose acetate, cellulose triacetate, cellulose propionate, cellulose acetate propionate, cellulose butyrate and cellulose acetate butyrate; vinyl polymers such as poly(vinyl acetate), poly(vinylidene chloride), poly (vinyl butyral), copolymers of vinyl chloride and vinyl acetate, polystyrenes, poly(methyl methacrylate), copolymers of alkylacrylates and acrylic acid, etc.; polyesters such as the esterification product of p-cyclohexanedicarboxylic acid and 2,2,4,4-tetramethylcyclobutane-1,3-diol, as well as additional polymers such as polyphenylene oxides, terpolymers of ethylene glycol, isophthalic acid and terephthalic acid and terpolymers of p-cyclohexane dicarboxylic acid, isophthalic acid and cyclohexylenebismethanol.

Photographic elements utilizing the light-sensitive diazotype compositions of this invention are conveniently prepared by coating such a composition onto a support material by means such as immersion, flow coating, whirl coating, brushing, doctor blade coating, hopper coating and the like to prepare a light-sensitive layer. Advantageous support materials include conventional photographic film base materials, for example, cellulose esters such as cellulose acetate, cellulose triacetate, cellulose acetate butyrate, etc., poly a-olefins such as polyethylene and polypropylene, polyesters such as poly(ethylene terephthalate), polystyrenes, polycarbonates, as well as metals such as zinc and aluminum and paper including polyethylene and polypropylene coated papers. Other support materials that are suitable for use herein are known in the art.

Coating is typically by solvent coating means, since it offers the potential for rapid, convenient, continuous operation. Coating is'eflected by first dissolving the photographic image-forming composition in a suitable solvent, along with a matrix polymer if desired. Exemplary matrix polymers are described hereinabove. The coating solution conventionally contains from about to about 20 weight percent solids, and preferably from about 8 to about 15 percent solids. In that solution, if a matrix polymer is utilized, the photographic image-forming components are typically included in an amount of from about 20 to about 50 parts by weight per 100 parts of polymeric binder, with concentrations in the range of from about 25 to about 45 parts per 100 parts of matrix polymer being preferred. Wider variations are possible where desired, but .the abovementioned ratios are typical for most conventional preparations. After coating by such means as whirl coating, brushing, doctor blade coating, hopper coating or the like, typically at a Wet thickness of from about 25 microns to about 125 microns, the coated material is dried to prepare a composite photographic element of this invention.

The diazotype compositions of this invention, including a boric acid ester such as those described herein, are advantageouslyrapidly processibleunder a wide variety of proc s sing conditions. Moreover, they exhibit significant resistance to undesirable precoupling, even at elevated temperatures and under high humidity conditions, this resistance being maintained for long periods of time (e.g. 6 months to 1 year).

After the light-sensitive layer has dried, the resultant elements can be imagewise exposed and developed to prepare a positive azo dye image corresponding'to the original. Exposure is typically to a light source rich in ultraviolet rays, such as a mercury arc lamp, a photoflood lamp or the like. Image development is conveniently accomplished by contacting the exposed element with an alkaline medium such as moist ammonia vapor at ambient pressure or high pressure anhydrous ammonia gas, which promotes the reaction ofdiazonium salt and coupler compound to form an azo dye image. No further image stabilization is necessary.

The following examples are included for a further understanding of the invention.

EXAMPLE 1 -A light-sensitive diazotype composition is prepared containing the following ingredients:

The composition is coated using a doctor blade onto a subbed poly(ethylene terephthalate) support material to prepare a photographic element. After drying, the thickness of the light-sensitive layer is about 7.5 microns. Portions of the element so prepared are stored under dark conditions at 21 C. and 100% relative humidity for a A light-sensitive diazotype composition containing the following ingredients is prepared:

G. Cellulose acetate-butyrate 7.220 Acetone 49.280 Methanol 19.420 Methyl Cellosolve 7.520 5-su1fosalicylic acid 0.306 2,5 dibutoxy 1 morpholinobenzene diazonium sulfate with 20% tartaric acid 1.530 2'-methoxy-3-hydroxy-2-naphathanilide 0.788 1-hydroxy-2-naphthopiperidide 0.497 Propylene oxide 0.050

Additive A as in Example 1 12.620 Tricyclohexyl boric acid ester 0.769

The composition is coated using a doctor blade apparatus onto a subbed poly(ethylene terephthalate) support to prepare a photographic element. After drying, the lightsensitive layer has a thickness of about 7.5 microns. Portions of this element are then stored under dark conditions at 38 C. and relative humidity for a period of hours. Minimum density of the unexposed portions rises by 0.38 after the storage period. Density measurements are obtained as in Example 1.

EXAMPLE 4 A photographic element is prepared according to the procedure of Example 3, except that tricyclohexyl boric acid ester is omitted from the diazotype composition. Af-

ter storage of samples as in Example 3, the minimum density rises to 0.51, density measurements being obtained as in Example 1.

EXAMPLE 5 The unexposed photographic element portions of Examples 1, 2, 3 and 4 are processed by treatment with anhydrous ammonia gas at a temperature of 55 C. in a General Aniline and Film Ozalid Junior Ozamatic Processor. The development rate of the portions from Examples 1 and 3 (containing a boric acid ester) is about twice as rapid as that for the portions from Examples 2 and 4 (boric acid ester omitted). Comparative development rates for the photographic elements of Examples 1 and 2 are summarized below in tabular form, the rates being expressed in percent of developed density as a function of time.

Percent completion of development l 1 Percent of maximum developable density.

Comparative results are obtained with a comparison of elements from Examples 3 and 4. A comparison of the results appearing in the above table is graphically presented in the accompanying drawing. In the graph, the vertical axis is calibrated for a percentage of the maximum visible difiuse density obtainable in a completely developed element. The horizontal axis is calibrated in seconds corresponding to the development time of each element. As indicated on the graph, the lower plotted curve indicates the development rate of a diazotype composition which does not contain a boric acid ester. The upper plotted curve indicates the increased development rate obtained with a like diazotype composition, but with tricyclohexyl boric acid ester added as a combined pre-coupling inhibitor, development accelerator. It is seen by reference to the graph that the rate of development with the boric acid ester present is significantly accelerated with developed density being increased by a factor of about 2.5 at 24 seconds development time.

EXAMPLE 6 The procedures of Examples 1, 2, 3, 4 and 5 are repeated in three separate sets, except that in those elements containing a boric acid ester, the following esters are used in lieu of tricyclohexyl boric acid ester.

Set 1triethyl boric acid ester, Set Z-triphenyl boric acid ester, Set 3tri-p-chlorophenyl boric acid ester.

Similar results are obtained.

The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be eflected within the spirit and scope of the invention.

I claim:

1. A diazotype composition consisting essentially of a light-sensitive diazonium salt, a coupler compound which can react with said diazonium salt to form an azo dye, a film-forming, hydrophobic polymeric binder, an acidic stabilizer and, as a combined precoupling inhibitor-development accelerator, a triester of boric acid and a monohydric alcohol.

2. A diazotype composition as described in claim 1 wherein said boric acid ester is present in an amount of up to about 25 parts by weight per 100 parts by weight of said hydrophobic polymeric binder.

3. A diazotype composition as described in claim 1 wherein said boric acid ester is present in an amount ranging from 5 to parts by weight per 100 parts by weight of said hydrophobic polymeric binder.

4. A diazotype composition as described in claim 1 wherein the boric acid triester is selected from the group consisting of trialiphatic alkyl boric acid esters, triaryl boric acid esters and tricycloalkyl boric acid esters.

5. A diazotype composition consisting essentially of a film-forming, hydrophobic polymeric matrix containing therein a light-sensitive diazonium salt, a coupler compound which can react with said diazonium salt to form an azo dye, an acidic stabilizer and as a combined precoupling inhibitor-development accelerator, a boric acid triester selected from the group consisting of:

(a) trialiphatic alkyl boric acid esters wherein the alkyl moiety has from 1 to 8 carbon atoms,

(b) triaryl boric acid esters wherein the aryl moiety is selected from the group consisting of a phenyl radical and a naphthyl radical, and

(c) tricycloalkyl boric acid esters having from 4 to 6 nuclear carbon atoms in the cycloalkyl ring.

6. A diazotype composition as described in claim 5 wherein the boric acid triester is selected from the group consisting of a trimethyl boric acid ester, a triethyl boric acid ester, a tripropyl boric acid ester, a triphenyl boric acid ester, and a tricyclohexyl boric acid ester.

7. A diazotype composition consisting essentially of a film-forming, hydrophobic polymeric matrix containing therein a light-sensitive diazonium salt, a coupler compound which can react with said diazonium salt to form an azo dye, an acidic stabilizer and, as a combined precoupling inhibitor-development accelerator, a tricyclohexyl boric acid ester in an amount ranging from 5 to 10 parts by weight per 100 parts by weight of said polymeric matrix.

References Cited UNITED STATES PATENTS 1,758,676 5/1930 Schmidt et al. 96-91 3,294,542 12/1966 Sus et al. 96-91 3,362,825 1/1968 Moskowitz et al. 96-91 X 3,386,827 6/1968 Aebi et al 96-49 X 3,409,434 11/ 1968 Landberge et al 96-75 3,567,453 3/1971 Borden 96-91 FOREIGN PATENTS 1,552,166 11/1968 France 96-75 OTHER REFERENCES Muller, P.: Precoating of Diazotype Paper, Tappi, August 1965, pp. 55A, 56A, 57A, 58A and 59A.

CHARLES L. BOWERS, JR., Primary Examiner U.S. Cl. X.R. 96-49,

"H050 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. $679421 Dat d July 1 972 Inventor(s) George P. Kasper I It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2, line 9, dye, as" should read ---dye d,

Column 3, line 1! "acid anion" should read ---Z is an acid anion---.

Signed and sealed this 27th day of May 1975.

(SEAL) Attest:

C. MARSHALL DANN RUTH C. MASON Commissioner of Patents Attesting Officer and Trademarks

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