5. AN IMPROVED PHOTOGRAPHIC MATERIAL ESSENTIALLY COMPRISED OF A PAPER BASE HAVING A COATING ON AT LEAST ONE OF THE SURFACES OF SAID BASE, COMPRISING GELATIN HAVING INCORPORATED THEREWITH FROM 10% TO 50% OF A POLYMERIC REACTION OBTAINED BY REACTING STYRENE WITH MALEIC ANHYDRIDE, FOLLOWED BY THE TREATMENT THEREOF WITH AMMONIA, SAID GELATIN-POLYMERIC COATING BEING OVERCOATED WITH A LAYER CONTAINING A FORMALDEHYDE-SENSITIVE PHOTOGRAPHIC LAYER.
2,739,062 Patented Mar. 20, 1956 METHOD OF SIZING PHOTOGRAPHKC PAHER AND RESULTANT PRODUCT William H. Griggs and Warren T. Heard, Rochester,
N. Y., assignors to Eastman Kodak Company, Rochester, N. Y., a corporation of New Jersey No Drawing. Application January 2, 1953, Serial N 0. 329,438
Claims. CI. 95-88) This invention relates to a new and improved method of sizing paper for photographic purposes and the resultant new photographic paper product. More particularly this invention relates to a new method of the class described and photographic paper product wherein the paper product is characterized by being particularly suitable for accepting certain types of photographic coatings.
It is well known in the paper art that many of the uses to which paper is put require that the paper fibers be at least partially non-absorbent toward liquids, or in certain instances the absorbency is controlled. This has been accomplished by treatment of the paper fibers referred to as sizing. One method of sizing in extensive use apparently involves the application of a gelatin or glue coating to the surface of the paper. The gelatin may contain other materials such as starch fillers and the like, as will be discussed hereinafter. Such type of sized paper has been extensively produced and much of it used for photographic purposes. That is, the sized paper is overcoated with various photographic coatings such as emulsion coatings and the like. However, in recent years in some instances difliculties have been experienced from the photographic standpoint, such as instability of photographic coatings or components therein.
Investigations indicate that certain carbonyl compounds or the like in the gelatin sizing may migrate from the sizing or otherwise enter the photographic layers and adversely affect some couplers, or developers in said layers. In other Words, the paper sizing may directly or indirectly be a factor in reducing the effectiveness of the photographic paper product or otherwise causes difficulty such as the obtaining of unsatisfactory quality when using the product. It is therefore apparent that provision for correcting or minimizing the aforesaid difiiculties represents a highly desirable result.
After substantial investigation we have found paper sizing materials and a method of paper sizing as will be described in detail hereinafter, which while giving a paper photographic product of substantially the same appearance and having as good or better properties as conventionally sized, represents a distinct improvement over the prior art in that our new method and sized product may be readily overcoated with numerous diflerent type layers containing various developers, couplers, etc. without difficulties of the type referred to above.
This invention has for one object to provide a new method of sizing paper for photographic uses. Another object is to provide as a new product a photographic paper sized in a special manner. Still another object is to provide a photographic paper sized or coated with one or more layers of sizing materials which arerelatively non-injurious toward certain components of photographic coatings. Still another object is to provide a new composite photographic paper product made up of a plurality of elements including paper base, gelatinpolymer size and one or more photographic layers, all of which elements are relatively compatible. Other objects will appear hereinafter.
As indicated above, there were certain instances in connection with photographic papers prepared by prior art procedure where photographic layers containing couplers, developers or the like, of a type to be referred to in detail hereinafter, were not as effective as they should be, or the layers were otherwise impaired. We have found that the cause of such difiiculties may be due to a substantial extent to the gelatin sizing containing an aldehyde such as formaldehyde. That is, this aldehyde which has been commonly added to gelatin may migrate into the photographic layer or otherwise adversely affect such layers containing developers, couplers and the like. Apparently in the prior art it has heretofore been regarded as necessary or desirable to put rather substantial amounts of formaldehyde in gelatin in order to render the gelatin satisfactory for use as a sizing. That is, the art is replete with information relative to formaldehyde treatment of gelatin so that gelatin sizes commercially used may contain aldehyde.
We have found, in accordance with the present invention, that it is possible to avoid the use of formaldehydetreated gelatin thereby obviating or minimizing difliculties from the photographic standpoint discussed above. That is, in general in accordance with our invention, a good grade of paper base may be sized with a gelatin (CHCsH5-CH2CHCONH2-CHCOO(NH4) a: combination where (-CHCOH5-CH2CHCONH2CHCOO; NI-Li) 3:
represents a polymer in which said monomer is repeated x times. This gives a sizing of comparable physical qualities or better qualities than those obtained by prior art gelatin sizes. Sized photographic paper is then overcoated with photographic coatings such as emulsion coatings and the like containing various developers, couplers, either alone or in combination with any of the usual sensitive silver salts. This product may then be further overcoated with additional layers of the size aforementioned or additional photographic layers. All of the above procedure may be carried out on the same equipment that has been previously used for applying conventional sizing and coating layers. The resultant product in appearance, physical properties and the like, is the same as existing photographic paper stock but possesses improvement in that the paper product of the present invention is more stable photographically as already discussed as respects developer or coupler components.
The chemical compound referred to above may be prepared by reacting an unsaturated hydrocarbon exemplified by styrene, with an anhydride of a dibasic acid exemplified by maleic anhydride, followed by the reaction of the polymeric product with ammonia. There are a number of ways of carrying outthe reaction and for further details reference may be made to U. S. Patent Nos. 2,313,565 and 2,698,794. The exact manner of forming the polymeric material, which for convenience herein may be referred to as SMA (styrene-maleic anhydride-ammonia), is not a part of or a limitation upon the instant invention.
For a more complete understanding of our invention reference will be made to certain specific examples which follow and which examples are set forth for illustrating some of the preferred embodiments of our invention. In these examples the paper base is preferably of high grade uncontaminated stock. That is, the paper fibers may come from either wood pulp or cotton cellulose and preferably the pulp for the paper is disintegrated and friabllated in stainless steel, tile-lined or plated equipment in order that the paper stock be free of contamination. While the sizing agent of the present invention may be added to the resultant uniform blend of cellulose fibers Id in water, as will be apparent from the description which follows, we prefer in most instances to apply a surface or tub sizing in addition to, or in place of, sizing in the beater. The relatively pure paper stock as just described is subjected on the continuous moving wire of paper making machines to the process of water removal, the water drainage being assisted by suction boxes and pressure rolls until the paper base sheet is obtained at the end of the moving wire. This sheet then traverses the dryer stacks which are made up preferably of heated revolving chromium plated iron drums and after calendering, the paper stock is wound into rolls and is ready for further treatment in accordance with the present invention. in the description set forth in the examples which follow it will be assumed that a suitable high grade paper has been prepared along the lines aforementioned. This paper may contain baryta or the like components as may be conventional, although such features are only briefly mentioned herein.
Example I In accordance with this example, approximately 42 parts by weight of gelatin was soaked in 200 parts by weight of cold water for about one hour. Solution of the gelatin was accomplished by heating to about 115 F. and adding approximately 745 parts of hot water. There was then added 125 parts by weight of a aqueous solution of being very careful to keep the pH between 4.5 and 5. This gelatin-SMA size solution is then cast on a support and dried. It will be noted that the resultant gelatin- SMA film so obtained is insolubilized to a degree entirely comparable to the prior art type of gelatin which has been formed from a solution containing formaledhyde, chromic chloride and the like.
The gelatin-SMA solution of the present invention may be used to size photographic paper stock. That is, the photographic paper stock may be passed under or over a coating roll or other device for applying a thin layer of size to the paper base. The sized paper may be partially or fully dried by passing through a chamber in which warm air is circulated, or the sized paper, for example with limited drying, promptly passed to further coating operations where photographic layers are applied as will be described in greater detail in examples which follow.
It will be observed that while in the above example the incorporation of was to the extent of about (based on the weight of the gel), this is not intended to restrict the concentration at that level. We have found that concentrations of SMA as low as 10% are quite useful as are concentrations as high as However, around 20 to 35% seems quite satisfactory and there is usually no need of incorporating higher amounts. In instances where the photographic paper sized in accordance with the present invention is to be further coated with layers containing developers or the like, it may be desirable to use lower amounts of SMA, say of the order of about 10% as just mentioned.
As already pointed out, the pH during the addition of the small amount of acid, say the addition of a limited quantity of 0.1 N-HCl. Also the stability of the gelatinmixture may be improved by lowering the pH to about 3.5 where higher amounts of the polymeric material are used, as in instances where 4050% of the polymer is being incorporated into the gelatin.
Example II it was caiendered and then over-coated with a photor graphic layer.
Example 111 in accordance with this example, paper of the type described was passed through a tub size pan immediately after the first drying section on the paper machine. The size pan contained a gel-SMA size comparable in makeup to that of Example I. The SMA concentration (based on gel weight) can be varied in accordance with Example I. The gel concentration can be varied from 2-5 parts per parts solution.
Example IV In accordance with this example photographic paper of a type as already described, after being sized with gelatin- SMA and suitably further processed, was then overcoated with a photographic layer. In this instance this layer contained one or more of the following developing agents: 3,4-dihydroxy diphenyl, 2,5-dihydroxy diphenyl, 5,6,7,8- tetrahydronaphthohydroquinonc, and 2,3-dihydroxy diphenyl. in addition, the product contained certain amounts of the usual silver halide components and antiabrasion overcoatings were applied.
Subsequent use, observation and test of this photographic paper sized in accordance with the present example, indicated that even after several months this product was stable, there being no evidence of developer disintegration.
Example V In accordance with this example, paper of the type aiready described was suitably coated with a baryta coating and thereafter sized with gelatin-SMA size of the present invention. The sized coating was suitably processed by calendering, after which a plurality of coatings were applied, which coatings contained one or more of the magenta and other couplers described in U. S. Patent No. 2,322,027, such as for example:
l-p-sec. amylphenyl-3-n-amyl-5-pyrazolone 2-cyanoacetyl-5-(p-sec. amylbenzoylamino)-coumarone 2-cyanoacetylcoumarone-5-(n-n-amyl-p sec. amylsulfanilide) Z-cyanoacetylcoumarone-S-(N-n-amyl-p-tert. amylsulfanilide) 2-cyanoacetylcoumarone-S-sulfon-N-n-butylanilide 2-cyanoacetyl-5-benzoylamino-coumarone Z-cyanoacetylcoumarone-S-sulfondimethylamide 2-cyanoacctylcoumarone-S-sulfon-N-methylanilide 2-cyanoacetylnaphthalene sulfon-N-methylanilide Z-cyanoacetylcoumarone-5-(N-- -phenylpropyl) p tert.
amylsulfonanilide l-p-laurylphenyl-3-methyl-5-pyrazolone 1-fl-naphthyl-3-amyl-S-pyrazolone 1-p-nitrophenyl-3-n-amyl-5-pyrazolone 1-p-phenoxyphenyl-3-n-amyl-5-pyrazolone l-phenyl-3-n-amyl-5-pyrazolone V 1,4-phenylene bis-3- l-phenyl-S-pyrazolone) N-amyl-p-benzoylacetarninobenzenesulfonate N-(4-anisoylacetaminobenzenesulfonyl) N benzyl mtoluidine N-(4-benzoylacetaminobenzenesulfonyl)-N benzyl mtoluidine When we refer to magenta and yellow couplers we refer to chemical compounds of the type just enumerated.
The product was then further finished in conventional manner. Observation and tests at the end of six months indicated that the couplers were still in an efficient, active 90 form and that no substantial disintegration or change thereof had occurred.
Example VI In accordance with this example, sizing solutions were made up as described in Example I except that citric acid, acetic acid, or dilutesulfuric acid were used to adjust the pH of the solution to the level described. The sizing solution was applied to the paper as described in Example I with similar results. no
Example VII In accordance with this example, photographic paper stock as previously described was sized in a suitable manner with a gelatin-SMA solution as in Example I. The
sized stock was then overcoated with a sensitized trans- 35 fer material useful in photomechanical reproduction processes similar to those described in U. S. Patent No. 2,596,756. The sizing had no deleterious effects on the sensitive materials which are obtained with regular formaldehyde hardened sized paper. 40
It can be seen from the foregoing that we have provided new and improved photographic paper product and method for the production thereof, in that, while the paper product is comparable to the prior art product in all general respects, nevertheless our product exhibits ini- 45 provement in that it is relatively free of instability due to prior art sizing. Our product may be made on existing equipment by substantially the same technique heretofore used, and in view of the limited amount of change thus ammonia, incorporating 10 to 50% by weight of said reaction product with gelatin while controlling the pH to less than 5 during said incorporation to form a polymericgclatin size and then applying said size to a surface of a good grade paper, at least partially drying the paper thus coated, whereby an improved paper for photographicuses is obtained.
2. A process for the manufacture of an improved gelatin coated paper which is particularly adapted for use as a base material to receive photographic coatings, which comprises obtaining a polymeric reaction product comprising the product obtained by reacting styrene with maleic anhydride, followed by the reaction thereof with ammonia, incorporating to by weight of said reaction product with gelatin while controlling the pH to less than 5 during said incorporation to form apolymericgelatin size, and then applying said size to a surface of a good grade paper, at least partially drying the paper thus coated, whereby an improved paper for photographic uses is obtained. I
3. A process for the manufacture of an improved paper which is particularly adapted for use as a base material to receive photographic coatings which comprises obtaining a polymeric reaction product having the properties of the reaction product obtained by reacting styrene with maleic anhydride, followed by the treatment thereof with ammonia, incorporating from 40% to by weight of such polymeric reaction product with gelatin, during said incorporation maintaining a pH below 3.5 by adding a suitable amount of acid to the polymer-gelatin composition, thereafter applying said polymer-gelatin combination to at least one of the surfaces of a good grade paper whereby an improved paper for photographic purposes is obtained.
4. An improved treated paper particularly adapted for receiving photographic coatings comprising a paper base, a coating on at least one of the surfaces of said base, said coating being essentially comprised'of gelatin having incorporated therewith from 10% to 50% of a polymeric material obtained from the reaction of styrene with maleic anhydride and then with ammonia.
5. An improved photographic material essentially comprised of a paper base having a coating on at least one of the surfaces of said base, comprising gelatin having incorporated therewith from 10% to 50% of a polymeric reaction obtained by reacting styrene with maleic anhydride, followed by the treatment thereof with ammonia, said gelatin-polymeric coating being. overcoated with a layer containing a formaldehyde-sensitive photographic layer.
required, our invention readily adapts itself to applica- 50 tion to existing industry.
1. A process for the manufacture of an improved gelatin coated paper which is particularly adapted for use as a base material to receive photographic coatings, which comprises obtaining a polymeric reaction product comprising the product obtained by reacting styrene with maleic anhydride, followed by the reaction thereof with References Cited in the file of this patent UNITED STATES PATENTS 1,623,522 Bent Apr. 5, 1927 2,313,565 McDowell Mar. 9, 1943 FOREIGN PATENTS 676,459 Great Britain July so, 1952