US3537856A - Light-sensitive photographic composition - Google Patents

Description

United States Patent Claims priority, application Japan, Aug. 26, 1 965,

- lli/52,123

Int. Cl. G03c 1/72 US. CI. 9690 11 Claims ABSTRACT OF THE DISCLOSURE A light-sensitive photographic composition comprises, as the light-sensitive component, an effective proportion of a compound of the formula wherein A is a member of the group consisting of H and Ilii t. X is a member of the group consisting of O, S, phenyl and phenyl substituted with lower alkyl; Z is a member of the group consisting of N, O, S and --N-Y, wherein Y is a member of the group consisting of lower alkyl, aryl and aralkyl; R and R alike or different, are each a member of the group consisting of straight and branchedchain lower alkyl, phenyl, phenylalkyl, substituted phenyl and substituted phenylalkyl with the phenyl radical substituted with a member of the group consisting of lower alkyl, lower alkoxy, halogen, amino, substituted amino, nitro, cyano, and alkoxy carbonyl; R is a member of the group consisting of cyano, acyl and alkoxy carbonyl; and R is a member of the group consisting of cyano, alkoxy carbonyl, nitro, acyl, carbamoyl and substituted carbamoyl.

This invention relates to a new light-sensitive, photographic composition containing, as a light-sensitive component, a chemical compound having a group of the after-specified structure.

It is a principal object of the present invention to provide a light-sensitive composition which is capable of forming a stable image of the good tone quality by simple procedures and which has good stability during storage. Some additional advantages and characteristics of the present invention will be apparent from the following description.

In the prior art of photography, a number of lightsensitive compounds including silver halide compounds, diazo compounds, etc. have been known and used in various forms. All these known light-sensitive compounds, however, have one or more disadvantages. For example, a light-sensitive photographic composition which contains silver halide as a light-sensitive component is most widely 3,537,856 Patented Nov. 3, l97 0 light-sensitive silver halide composition requires complicated procedures and equipments. Furthermore silver which is essential as a starting material is very expensive. The actual use of such silver halide composition usually necessitates a series of wet treatments including develop ment and fixation. On the otherhand, a light-sensitive diazotype composition although it is inexpensive has poor tone quality and it also necessitates troublesome wet treatments or use of irritating ammonia vapor. Further it is not so stable during the storage for a long period. A binary light-sensitive composition comprising diarylamine and halogenated hydrocarbon is also well known, which, however, is diflicult to be practically used because the halogenated hydrocarbon is remarkably toxic.

In accordance with the present invention, there is pro vided a new light-sensitive composition which is free from the disadvantages encountered in the prior art. A lightsensitive compound having a group of the specific structure is rather inexpensive and can be synthesized by simple procedures. Further, the light-sensitive compound can be easily prepared as a light-sensitive composition which will yield a stable image of the good tone quality through photographic treatments.

Now the present invention will be explained in full detail. A light-sensitive photographic composition of the present invention comprises, as a light-sensitive component, a chemical compound having in its molecular structure a group represented by the formula s} n j l wherein X means oxygen or sulfur atom, and Z means oxygen or sulfur atom or a group =N-Y in which Y is lower alkyl, aryl or aralkyl. Typical compounds which are suitable as light-sensitive components in the present invention will be generically represented by any one of the following general Formulas I to III wherein Z is oxygen or sulfur atom or a group =NY (in which Y is lower alkyl, aryl or aralkyl), and R and R have the same significance as in the above general Formula I. The phenyl group or groups of the general Formula II are optionally substituted with lower alkyl or the like.

R1 1 1 1 N H H X: 2 y X R t R2 R2 (III) wherein X, R R R and R have the same significances as before.

Typical compounds which fall within the category of the above general Formula I are as follows:

COMPOUND I 1,3-dibenzyl 6- [cyano (ethoxyearbonyl)methy1] 1,2 3,6=tetnahydrocycloheptimidazol-'20ne COMPOUND II CH 1's /C I M-P. 143 C. HmCsOOC \N M.P. 153 C. HsCzO O C 1,3-dihenzyl-6- [cy-ano hexyloxycarbonyl) methyl] 1,2,3,6-tetmhydrocycloheptimidazoLZ-one COMPOUND III 1,3-dibenzyl-6-[earbamoylcyanomethyl]-1,-2,3,6- tetrahydrocycloheptimidazol-Z-one COMPOUND IV gradually reddening by heating 1 Q 1,3-dibenzyl-6-dicyanomethyl-1,2,3,6- tetrallydroeycloheptimidazol-2-one COMPOUND V 1,3-dibenzy16- [ethoxycarbonylnltnomethyl] 1,2,3,fi-tetrah drocyeloheptimidazol-z ne C- OzN COMPOUND VI ua. :O

1,3dianisyl-G-dicyanomethyl-l,2,3,G-tetral1ydrocycl0 heptimidazol-Z-one COMPOUND VII slow decomposition by heating 1,3-dibenzyl6-dieth0xycarbonylmethyl-l2,3,6-

tetrahydrocycl0heptimidaz0l-2-0ne All these Compounds I to VII are new compounds which have never been disclosed in the known literatures. They can be prepared by the reaction of a 1,3-disubstituted-2- 0x0-cycloheptaimidazolinium halide of the formula R1 are =0 l (wherein R and R are the same as defined before and X is halogen or acid residue) with an active methylene compound of the formula (wherein R and R are the same as defined before) in the presence of a condensing agent. For illustration, the preparation of the Compound I will be mentioned in Example A.

EXAMPLE A Bis (2-pheny1-(SH-cycloheptoxazol-G-yl) malononitrile COMPOUND VIII COMPOUND IX N N H (IJN H 3 w I Q 0 i O reddening at O O 0 02115 about C.

Ethyl bis (2-phenylGILcyclohept0xazol-G-yl) cyanoacetate COMPOUND X about 145 C.

Bis (2-phenyl-6Hcycl0heptoxaz01-Gy1) cyanoacetamide COMPOUND XI reddening at about 142-3 C.

Bis (1-p-tolyl-2-pheny1-1,6-dihydroeycloheptimidazol- 6-5 1) malononitrile These compounds VIII to XIare new compounds and can be synthesized by the reaction of a cycloheptatrienium compound of the formula (wherein X and Z are the same as defined before) with an active ,methylene compound of the formula (wherein R and R are the same as defined before) in the presence of a condensing agent. For illustration, the procedures for the preparation of the Compound VIII will be mentioned in Example B.

EXAMPLE B To 0.8 g. of metallic sodium dissolved in 100 ml. of ethanol are added 2.1 g. of malononitrile and 10 g. of 2-phenyl-oxazolo-tropilium monomethyl sulfate. The resiilting solution is stirred at room temperature for 6 hours. The separated crystals are collected by filtration and washed with ethanol. The mass is added with chloroform and washed with water twice. The chloroform layer is dried over anhydrous sodium sulfate. Then it is treated .with active carbon and concentrated at a bath temperature of not more than 50 C. under reduced pressure. The crystalline residue is added with benzene and then separated by filtration. 5.0 g. of bis(2-phenyl-6H- cycloheptoxazol-6-yl)malononitrile is obtained.

'Typical'compound belonging to the category of the general Formula III is as follows:

COMPOUND XII N-methyl-bis (1,3-dibenzy1-1,2,3,6 tetrahydro cyclo heptimidazo1-2 n-6-yl) eyanoacetamide The preparation of this compound XIII will be govern in Example'C.

EXAMPLE C To 0.2 g. of metallic sodium dissolved in 40 ml. of ethanol is added 0.72 g. of cyanoacetic methyl amide. To the solution is then added 3.0 g. of 1,3-dibenzyl-2-oxocycloheptaimidazolinium chloride dissolved in 50 ml. of ethanol. The mixture is stirred at room temperature for 5 hours. After standing the mixture overnight, it is filtered to remove undissolved matters. The filtrate is concentrated under reduced pressure. The oily residue is dissolved in ethyl acetate and the resulting solution is passed through a column packed with alumina. Then the solution is concentrated and the residue is recrystallized from cyclohexane to obtain 1.0 g. of N-methyl-bis-(l,3-dibenzyl 1,2,3,6 tetrahydrocycloheptimidazol 2 on 3-y1)- cyanoacetamide, M.P. 7 C.

The above-referred compounds can develop color when they are exposed to ultraviolet irradiation, and accordingly, a composition which contains one or more than two of these compounds is useful as a light-sensitive composition in the photographic art. As is well known to those skilled in the art, the light-sensitive composition with which the invention concerns may additionally comprise one or more auxiliary components to improve the properties of the composition. For example, alkanol amines (e.g. triethanol amine), polyalkylene oxide compounds, etc., can be used as effective sensitizers to increase the light sensitivity of the composition. Other suitable sensitizers include phenyl urethane, acrylamide, acetanilide, o-acetanisidide, diphenyl carbazide, benzalazine, maleic anhydride, phthalic anhydride, succinic anhydride, tartaric anhydride, potassium bichromate, etc. Incorporation of an aromatic amino or nitro compound as auxiliary component serves to control the color tone of the image resulting from ultraviolet irradiation of the composition. For example, phthalic, oxalic, benzoic, tartaric and malonic acids or their anhydride, m-hydroxydimethyl-aniline, methyl m-nitrobenzoate, 2-nitrohydroquinone methyl ether, etc. are suitable color-controlling agents. Diaminostilbenesulfonic acid or the like known optical whitening agent is effective to improve visible whiteness of the background of the image. Many other auxiliary components can be suitably selected depending on the purposes with reference to the known photographic techniques.

In the actual use of a light-sensitive photographic composition of the present invention, it is convenient to prepare the composition in the form of a light-sensitive layer coated on a support. Suitable supports include papers, cloths, film bases, metallic plates, etc. Generally, papers and film bases are suitable. For convenience, the term, a light-sensitive element, will be used hereinafter to mean a light-sensitive composition of the invention which is in the form of a layer coated on a support. Such lightsensitive element as referred to above can be prepared in several ways. Most simply, the light-sensitive composition which contains the light-sensitive compound together with or without any auxiliary compound is finely divided and then uniformly rubbed onto the surface of paper or the like support by means of buff rolls. In small scale preparation, the fine particles of the light-sensitive composition is rubbed onto the surface of paper by using absorbent cotton or soft cloth lump. More practically, however, it is advantageous to dissolve or disperese the lightsensitive component (and the auxiliary component), together with or without a binder, in an appropriate solvent and then coat the resulting solution or dispersion on a suitable support. Almost all of the light-sensitive compounds usable in this invention are soluble in ketones such as acetone or methyl ethyl ketone, acid esters such as ethyl acetate or butyl acetate, and cyclic oxy-hydrocarbons such as dioxane or cyclohexanone, and so, any one of these solvents can be conveniently used for preparation of a solution. On the other hand, water or an alcohol is suitable for preparation of a dispersion of the light-sensitive compound because the compound is sparingly soluble in these solvents. In film coating, use of a binder in combination with the light-sensitive compound is preferable. In coating of the solution containing the light-sensitive compound, a film-forming polymeric material which is well soluble in the solvent used is suitable as a binder. Typically usable are acrylic resin; polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinyl butyral or the like polyvinyl resin; and cellulose acetate, ethyl cellulose or other cellulose derivatives. For dispersion type coating, suitabe binders are water-soluble, alcohol-soluble polymeric materials including gelatine, gum arabic, polyvinyl alcohol, carboxymethyl cellulose, etc. In the preparation-f the coating solution, a lightsensitive compound and, if desired, an auxiliary compound are simply dissolved in a suitable solvent in which a binder has been dissolved. If the coating dispersion is to be prepared, a light-sensitive compound is ground with a small amount of acetone or the like and then the resulting mass, added with an aqueous gelatine, is treated by means of an ultrasonic disperser, ball mill, micron mill or the like, thereby to have desired dispersion. The coating solution or dispersion thus prepared can be applied onto a support by any procedures known per se in the art. Coating of the light-sensitive compound in the amount of 0.5- grams per square meter of the support is preferred. Generally, a light-sensitive element produced by rubbing of the fine particles of a light-sensitive compound or by using a dispersion of the light-sensitive compound yields a stable image with high contrast, whereas a lightsensitive element produced by using a solution of the light-sensitive compound yields a vividly colored image of the good tone quality which makes the composition adaptable to use in the reproduction of an image from a continuous tone photographic negative.

Imagewise exposure of the light-sensitive element to ultraviolet irradiation gives a color image which, when heated, is fixed with an increase of color density, to have good stability against further light exposure. The colored image thus obtained is of fine grain and high resolution, and it is stable during the long period of storage. In the practical use of the light-sensitive element, all the procedures are conducted in dry process not involving use of any liquid agent. Thus, the said element can be easily used without special care. In the particular embodiment using a light-sensitive element of the dispersion type coating, however, fixation by solvent treatment also is applicable. Further it is noted that reversal development of such light-sensitive element as above is possible.

As a light-sensitive element of the invention can develop color by light exposure, it is useful in so-called negative-positive method. Thus if a positive image is desired an original having a negative image should be employed. In a particular case, however, wherein excessive light exposure is given, reversal phenomenon which is alike solorization in a silver photographic process takes place so that the light-sensitive element is usable in the manner of a positive-positive method. As light exposure, ultraviolet irradiation is most eflicient. A mercury lamp, arc lamp, high power fluorescent lamp, etc. are recommended as light source. However, as far as sufficient illumination is assured, a usual incandescent lamp can be used in combination with a slide projector. The light-sensitive element thus exposed is then heated up to 100- 150 C. thereby to eifect fixation with simultaneous increase in image density. Heating may be elfected by various means. For instance, the light-sensitive element is passed at a speed of about 5 cm./sec. between hot rolls having a surface temperature of about lOO-l30 C. Insertion between two uniformly heated platens also is possible. Further alternatively, use of a hot air (120 C.) chamber or irradiation from an infrared lamp is acceptable for the purpose of fixation. In case of a lightsensi tive element of the dispersion type coating, solvent treatment may be made instead of heating, with the result of image fixation and increase of color density. For example, an organic solvent, such as pyridine, tetrahydrofuran, n-propyl alcohol, etc., to which is added an optional amonut of water to control the dissolving power of said solvent, is used to treat the light-sensitive element having been printed.

The following examples describe certain ways in which the principle of the invention has been applied, but are not to be construed as limiting its scope.

EXAMPLE 1 45 grams of a polystyrene resin Stylon (registered trade name, manufactured and sold by Dow Chemical Corp., USA.) is dissolved in 1 liter of methyl ethyl ketone. To the resulting solution is added 30 g. of the above-indicated compound (I) as light-sensitive component. After Well agitation, a light-sensitive solution is obtained, which is coated at the amount of 50 ml./m. on a photographic baryta paper and then dried. All the procedures mentioned above are carried out under yellow photographic safe light in a dark room, avoiding invasion of daylight.

The light-sensitive element thus prepared is superposed with a photographic negative bearing an original image and the resulting composite is exposed to irradiation from 1 kw. high pressure quartz mercury lamp for 5 seconds. Through a photochemical reaction which takes place in the exposed area of the element is formed a pale image. The element is then passed at a speed of 5 cm./sec. between hot rolls having a surface temperature of 120 C., thereby to effect fixation of the image while image density is remarkably increased. The resulting red-orange colored positive image has good tone quality and is so stable that it does not show any appreciable change even after one hour exposure to direct sunlight.

.By utilizing so-called reversal phenomenon, the same light-sensitive element can be used for obtaining reproduction of the positive-positive type. For instance, the light-sensitive element is superposed with a tracing paper bearing handwritten original and the composite is subected to irradiation from a mercury lamp for one minute. Thereafter, the element is heated by means of 120 C. hot rolls. A clear positive copy of the original is obtained.

Other light-sensitive elements can be prepared by repeating the above-mentioned procedures excepting that the equal amount of the compound (II), (HI), (X) or (XII) is used in place of the compound (I). The image color shade and specific speed of these light-sensitive elements produced thereby are as follows:

Specific Color shade speed, of image index Compound:

(I) (II)- 100 (III) 50 (IX) Orange 10 (XII) do--. 50

EXAMPLE 2 The light-sensitive solution as prepared in Example 1 is coated on a 0.12 mm. thick polycarbonate film base Konifoil C (trade name of Konishiroku Photo Industry Co., Ltd., Japan) and then dried. The light-sensitive film thus prepared is superposed with a photographic negative and then the composite is exposed in the same manner as in Example 1. After working up the film in the same manner as in Example 1, a transparent positive image is obtained, which is of no grain and has high resolution. A clear visible image is observed on a screen when the original image is projected at any desired magnification by means of a slide projector. The light-sensitive film of this example is useful for preparation of original slide plates or reproduction of microfilms.

EXAMPLE 3 The compound (X) is uniformly rubbed at the amount of 2 g./m. onto the surface of a coated paper by using absorbent cotton. The light-sensitive paper thus prepared is treated in the same manner as in Example 1. After printing (imagewise exposure) and thermal fixation, a

EXAMPLE 4 In a 2 litre-volume beaker, 30 g. of the compound (I) and 100 ml., of acetone are thoroughly mixed to form a pasty mass, to which is added 1 litre of a 4.5 aqueous gelatin solution. The total mass is then treated by means of a ultrasonic type homogenizer, Model USH-15Q (manufactured and sold by Ultrasonic Industry Co., Japan) to have a light-sensitive dispersion containing the fine particles of the light-sensitive component in gelatine. This dispersion is coated at the amount of 50 ml./m. onto the surface of a photographic baryta paper and then dried. The light-sensitive element thus prepared is treated in the same manner as in Example 1', thereby to obtain a clear positive image from a photographic negative. The light-sensitive element used in this example is characterized by that it gives an image which is higher in density and contrast and more vivid in tone quality than the image obtained in Example 1.

An alternative procedure for fixation of the-image obtained by using the light-sensitive element of this example is solvent treatment. For this purpose, the light-sensitive element bearing a pale image after printing is treated with a mixture of tetrahydrofuran and water (1:1) for several ten seconds, whereby fixation is completed with increasing image density. The fixed image is now stable even under daylight.

EXAMPLE 5 45 grams of polystyrene resin is dissolved in 1 l. of methyl ethyl ketone, and to the resulting solution are added g. of the above-indicated compound (XII) as light-sensitive component and 60 g. of m-dimethylaminophenol as image color-modifying agent. The .resulting mixture is well stirred to have a light-sensitive solution, which is then coated at the amount of 50 mL/m. on a photographic triacetate film base. The light-sensitive element thus prepared is superposed with a photographic negative and the resulting composite is exposed to ultraviolet irradiation from a 1 kw. mercury lamp for 10 seconds. Thereafter, the light-sensitive element is passed at the speed of 5 cm./sec. between hot rolls having a surface temperature of 120 C., thereby to effect fixation with an increase of image density. The resulting purplecolored, dense image is of non-grain and of high resolution and has good tone quality and satisfactorily high density. The image can be clearly seen on a screen by enlarged projection. If the procedures given in this example are repeated with exception of addition of the m-dimethylaminophenol, the image obtained thereby is orange in color and has insufficient density to effect production.

EXAMPLE 6 In a 2 litre-volume beaker, g. of the compound (I) as light-sensitive component and 100 ml. of acetone are well mixed to form a paste, to which are then added 1 litre of 4.5% aqueous gelatine solution and 5 ml. of 2% Teepol (trademark of Shell Chemical Co., U.S.A.; alkyl sulfate type anionic type surfactant). The total mixture is treated by means of an ultrasonic homogenizer to obtain a dispersion having the light-sensitive component dispersed therein. To the dispersion, 4 ml. of triethanol amine (sensitizer), 10 ml. of 1% mucochloric acid (gelatine hardener) and 8 ml. of 2% Leucophor (trademark of Sandoz Ltd, Switzerland; diaminostilbene sulfonic acid type optical whitening agent) are added. The mixture is thoroughly mixed. The light-sensitive dispersion thus prepared is coated at the amount of 50 mL/mfi on a photographic baryta paper and then dried.

The light-sensitive element thus obtained is used in the same manner as in Example 1. From a photographic negative, a clear, reddish orange-colored positive image is obtained. As the result of addition of the sensitizer,

the element of this example is twice faster in photographic speed than the'light-sensitive element of Example 1. Further, addition of the optical whitening agent results in improvement in whiteness of the background so that the image may be very clearly visible.

What we claim is:

1. A light-sensitive photographic composition which comprises, as the light-sensitive component, an effective proportion of a compound of the formula I wherein A is a member of the group consisting of H and R1 V p:

Z V I ka X is a member of the group consisting of O, S, phenyl and phenyl substituted with lower alkyl; Z is a member of the group consisting of N, O, S and -N-Y, wherein Y is a member of the group consisting of lower alkyl, aryl and aralkyl; R and R alike or different, are each a member of the group consisting of straight and branched-chain lower alkyl, phenyl, phenylalkyl, substituted phenyl and substituted phenylalkyl with the phenyl radical substituted with a member of the group consisting of lower alkyl, lower alkoxy, halogen, amino, substituted amino, nitro, cyano, and alkoxy carbonyl; R is a member of the group consisting of cyano, acyl and alkoxy carbonyl; and R is a member of the group consisting of cyano, alkoxy carbonyl, nitro, acyl, carbamoyl and substituted carbamoyl.

2. The light-sensitive, photographic composition of claim 1 which comprises, as the light-sensitive component, a member of the group consisting of compounds havin the formulae:

1?: R3 H H N \i R4 N I M (I) N H Rs H N i y-K) Z R Z (II) and 1 R1 1% 11: J O l C- 0 I ia I ia (III) with the proviso that when the compound is of Formula III R represents a cyano group and R represents a substituted carbamoyl group and that when the compound is of Formula I R; does not represent a substituted carbamoyl group.

3. A composition according to claim 2 wherein the light-sensitive agent is 1,3-dibenzyl-6-[cyano(ethoxycarbonyl)methyl] 1,2,3,5 tetrahydrocycloheptimidazol-1-2- one; 1,3-dibenzyl-6- [cyano (hexyloxycarbonyl) methyl] 1 2,3,6 tetrahydrocycloheptimidazol 2-one; 3-dibenzyl-6- (carbamoylcyanomethyl) 1,2,3,6 tetrahydrocycloheptimidazol 2 one; 1,3 dibenzy1-6-dicyanomethyl-1,2,3,6- tetrahydrocycloheptimidazol 2 one; 1,3-dibenzyl-6-(ethoxycarbonylnitromethyl) 1,2,3,6 tetrahydrocycloheptimidazol 2-one; 1,3 di-p-anisyl-6-dicyanomethyl-1,2,3,6- tetrahydroxycycloheptimidazol-2-one; or 1,3-dibenzyl-6- diethoxycarbonylmethyl 1,2,3,6-tetrahydrocycloheptirnidazol-2-one.

4. A composition according to claim 2 wherein the light-sensitive agent is bis(2-phenyl-6H-cycloheptoxazol- 6-yl)malononitrile; ethyl bis (2-phenyl-6H-cycloheptoxazol-6-yl)cyanoacetate; bis (2-phenyl-6H-cycloheptoxazol- 6 -yl) cyanoacetamide; or his (1-p-t0yly-2-phenyl-1,6-dihydrocycloheptimidazol-6-yl -malononitrile.

5. A composition according to claim 2 wherein the light-sensitive agent is N-methyl-bis (1,3-dibenyl-1,2,3,6- tetrahydrocycloheptimidazol-Z-on-6-yl) cyanoacetamide.

6. A light-sensitive, photographic composition as claimed in claim 1, wherein the composition is present in the form of a light-sensitive layer supported on a support.

7. A light-sensitive, photographic composition as claimed in claim 6, wherein said layer further comprises a sensitizer, a color-controlling agent and/or an optical whitening agent.

8. A light-sensitive, photographic composition as claimed in claim 7, wherein said sensitizer is selected from triethanol amine, phenyl urethane, acrylamide, acetanilide, o-acetanisidide, diphenyl carbazide, benzalazine,

maleic anhydride, phthalic anhydride, succinic anhydride, tartaric anhydride, polyethylene oxide and potassium bichromate.

9. A light-sensitive, photographic composition as claimed in claim 7, wherein said color-controlling agent is selected from phthalic, oxalic, benzoic, tartaric and malonic acids and their anhydrides, m-hydroxydimethylaniline, methyl m-nitrobenzoate and 2-nitrohydroquinone methyl ether.

10. A light-sensitive, photographic composition as claimed in claim 1, wherein the composition is in the form of a solution in which said light-sensitive compound, together with a film-forming binder selected from the group consisting of polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinyl butyral, acetyl cellulose, and ethyl cellulose is dissolved in an organic solvent therefor.

11. A light-sensitive, photographic composition as claimed in claim 1, wherein the composition is in the form of a dispersion in which said light-sensitive compound, together with a water-soluble polymeric binder selected from the group consisting of gelatine, gum arabic, polyvinyl alcohol, and carboxymethyl cellulose is dis persed in water.

References Cited UNITED STATES PATENTS 5/1968 Willems et a1. 9690 X 7/1964 Stewart et a1 96-90 X US. Cl. X.R.