US2872318A - Polystyrene film elements and subbing compositions therefor - Google Patents

Description

Feb. 3, 1959 c. B. STARCK 2,872,313

POLYSTYRENE FILM ELEMENTS AND SUBBING COMPOSITIONS THEREFOR Filed Feb. 14, 1958 GELAUN AND CELLULOSE N/T RATE ORIENTED POLYSTYRENE F/LM BASE GELAT/N AND SILVER HAL/DE GELAT/N AND CELLULOSE N/TRAT E ORIENTED POLYSTYRENE F/LM BASE GELAT/N AND S/LVER HAL/DE GELAT/N AND CELLULOSE N/TRAT E ORIENTED POLKSTYRENE F/LM BASE a\\\\\\\\\\\\\w GELAT/IVA/VD CELLULOSE N/TRAT E GELATYN AND S/LVER HAL/DE GELA77N AND CELLULOSE N/TRATE /O V///% OR/EIVTED POLYSTYRE/VE F/LM BASE zL\ GEL AT/N AND CELLULOSE xv/r/m r5 GEL/177A! LAYER CLEMENS B. STA/PCK INVENTOR.

ATTORNEY 8 AGENT United States Patent if POLYSTYRENE FILM ELEMENTS AND SUBBING COMPOSITIONS THEREFOR {Siemens Bernard Starch, Rochester, Eastman Kodak Company, Rochester, N. Y., a corporation of New Jersey Application February 14, 1958, Serial No. 715,295 r f.

a 18 Claims. ('Cl. 96-437) This invention relates to photographic film' or she'et 2,8 7 2,3 18 Patented Feb. 3,1959

However, such negatives produced from the materials available heretofore have not been entirely satisfactory in the above respects. Also, it is sometimes necessary to reduce or intensify'the negative images, and here too, the prior art materials have shown serious separation of I the emulsion from the film base in the regions where the Y., assignor to conventional reducing and intensifying solutions have been applied.

I have found that a very effective subbing composition for'oriented polystyrene sheeting and film base is obtained "I by dispersing gelatin and cellulose nitrate in a solvent elements wherein the film base is a highly hydrophobic 1.;

mixturecontaining-in addition to low boiling solvents from 520% by weight of the subbing composition of a' higher. boiling solvent, i. e. having a boiling points'ubstantiallyi above 120" C., from the group consisting of acetonyl acetone, butyl carbitol acetate cm oc mo'c mococm a mixture of 70-80% of a-methyl benzyl alcohol and 30-20% of acetophenone, but more especially mesityl 7 oxide. The subbing layer adheres firmly to the film of the above kind having an improved anchoring substratum (commonly known as a subbing layer) between the film base and the light-sensitive water-permeable colloid layer or emulsion disposed thereon, preferably a gelatin'o silver halide emulsion layer.

Oriented polystyrene sheeting has many desirable physical properties which make it attractive for use as a photographic film base. However, it is highly hydrophobic, and in order to secure adhesion to it of a normal type of. hydrophilic gelatino-silver halide emulsion layer, it is' necessary to provide one or more intermediate anchoring layers, so-called subbing or substratum layers. Such substratum layers are intended to provide firm adhesion of the polystyrene film base to the gelatin emulsion layer. To secure anchorage to the polystyrene film ba's'e, however, it is necessary to applya coating th'ereover from a solution of a suitable anchoring material in a solvent medium which has at least some solvent or swelling action on the polystyrene but which action is insuflicient to distort the surface of the film base. While various compositions and combination of layers have been proposed j for this purpose, none have proven entirely satisfactory in actual commercial practice. For example,

when solvents such as toluol, ethylene dichloride, methylene dichloride, acetone, etc.,. which are known to be active Solvents or swelling'solvents for polystyrene were used in the substratum compositions in varying concentrations, it

has been found that bad cra'zing of the film base surfacedeveloped, and when such subbed materials were .overcoated withemulsion, adhesion of the emulsion to the film base was found to be very poor. In addition, the.

solvents penetrated into the film base and destroyed dimensional stability. Also; the final photographic film element so produced showed serious skidding and spontaneous stripping after processing and drying. Another serious disadvantage of prior art photographic elements is in connection with graphic arts and cartographic processes wherein the exposed and processed negatives are subjected to scribing to produce sharp lines in the printed images, for example, in aerial'surveying wherein latitude and longitude lines are produced by scribing such lines through the emulsion layer of the exposed and processed negative. It will be obvious thatin this kind of process theemulsion must adhere tightly to the film base so that the scribed lines will have clean edges without any peeling basefahd when ove'rcoated with a light-sensitive emulsion, preferably a gelatino-silver halide emulsion layer, the film element thus obtained retains all of the desirable physical properties of oriented polystyrene film base with none of the above mentioned disadvantages of emulsion'skidding and stripping found with related prior art photographic elements.

' It is, accordingly, an object of the invention to provide a noveland'useful composition that adheres strongly to oriented polystyrene film base or sheets. Another objectis to provide a high stability photographic element wherein'a layer of the above composition is coated directly on at least one side of oriented polystyrene film base and wherein at least one of the coated sides is overcoated with a layer of light-sensitive emulsion, more particularly with a gelatino-silver halide emulsion layer. Anotherobject is to provide a process for preparing these novel materials. Other objects will become apparent hereinafter.

In accordance with the invention, my novel photographic elementsare prepared by applying a subbing composition on oriented polystyrene film base, preferably on both surfaces, dryingthe subbed film base and then applying on or more light sensitive compositions over at least one of the subbed surfaces, followed by drying the element so formed. Preferably only one of the subbed surfaces is overcoated with a light-sensitive layer, and the other-subbed surface is coated with a non-sensitive gelatin solutionwhich mayralso contain antistatic materials, filter dyes, are, which primarily serve to prevent curling of the film base and also avoids static charge'build up,

. essentially of from 0.407175% by weight of gelatin and back re'fl e ction, and the like.

Suitable subbing.compositions of the invention consist from 0.032-,0.l40% by weight of cellulose nitrate in a solvent, combination of acetone, lower saturated aliphatic alcohols of 1 to 3 carbon atoms such as methyl alcohol,

ethyl alcohol and isopropyl alcohol, and from 5-20% by weight of at leastone Off the previously mentioned suitable higher boiling solvents, and more particularly mesityl oxide; A conventional acid dispersing agent for gelatin such as acetic acid is employed in an amount varying from0.041.0% based on the total weight of the sub- I bingcomposition, together with from 0.8-3.5% of water,

even after prolonged storage of the scribed negative.

to promote dispersion of thegelati'n. Preferably, there is also incorporateda hardener for the gelatin varying in amount from a trace 0.001%) to not more than 0.026%, preferably in the form of CrCl -6H O.

Typical subbing compositions of the invention come smears within the ranges specified in the following general for- The cellulose nitrate is preferably a relatively low viscosity type having a nitrogen content of 11% by weight and being 80-90% soluble in alcohol. For optimum emulsion adhesion and film base appearance, a composition containing on a weight basis about 0.8% of gelatin and 0.064% of cellulose nitrate, and the remainder of the solvent combination containing mesityl oxide, as the high boiling component has been found to be the most satisfactory. When the solids are reduced below 0.4% of gelatin and 0.032% of cellulose nitrate per 100 parts of the solvent combination or increased substantially above the specified upper limits of 1.75% of gelatin and 0.1492 of cellulose acetate, poor bonding of the subbing composition layer to the oriented polystyrene film base results. However, not all higher boiling solvents are effective in obtaining the objects of the invention. For example, I have found that related solvents such as 3-heptanone,4-, methyl-Z-pentanone and hexachloro-1,3-butadi ene when substituted as the higher boiling solvent component in the aforesaid compositions give very unsatisfactory subbing compositions, i. e., the adherence of the gelatino-silver halide emulsion layer to the oriented polystyrene base is from poor to bad in any concentration under testing and use conditions, while other higher boiling solvents such as 2,6-dimethyl-4-heptanone, dibutyl carbitol and mixtures of acetophenone and wmethyl benzyl alcohol wherein the latter component is less than 70%, showonly slightly better adherence under the sameconditions as compared to those giving from poor to bad results.

While the subbing compositions of the invention can be applied to the oriented polystyrene film base by any conventional method such as dipping, spraying, etc., the

preferred method is to use a bead coating technique wherein the film base moves continuously and progressively under an applicationhopperf The temperature of thesubbing composition and the film base surface at point of application is advantageously maintained at a range of from about 50-120 F. After drying, a coating of gelatino-silver halide is applied over the subbed surface, also in a. continuous manner, as wellas any other coatings such as the mentioned backing layers on the reverse;

side which also has been subbed as above. The completed photographic element is then dried under conventional conditions of temperature and humidity. I

Film elements of the kind described above are shown in sectional views in the accompanying drawing.

As shown in Fig. 1 an oriented polystyrene film base is coated with a subbing layer 11 comprising gelatin and cellulose nitrate. In the preferred form, layer 11 also contains a hardener for the gelatin, e. g. chromic chloride.

The element shown in Fig. 2 is the same as that shownin Fig. 1, except that a gelatino-silver halide 12 is coated over the subbing layer 11.

The element shown in Fig. 3 is the same as that shown in Fig. 2, except that the subbing layer 11 is also coated on the back of the oriented polystyrenefilm base 10.

'The element shown in Fig. 4 is the preferred element and is the same as Fig. 3, except that an additional layer 13 of gelatin iscoated over subbing layerll on the back surface of theoriented polystyrenefilm base ,10'. Layer 4 13 is intended primarily to prevent curling, but may also contain suitable antistatic materials, filter dyes, and the like.

The manner of practicing my invention is further illustrated by the following examples:

Example 1 An oriented polystyrene film base was coated on both surfaces with the following subbing solution, the components being given as percent by weight:

ethyl alcohol, suiiicient to make a total of After drying, one or" the coated surfaces was overcoated with an ordinary gelatino-silver halide emulsion and the other surface was overcoated with an aqueous gelatin solution containing no silver halide. On drying and curing, no curl was observed. The photographic element thus obtained, on testing, showed highly satisfactory physical characteristics such as good flexibility without brittleness, and was outstanding as to dimensional stability and firm adherence of the emulsion layer to the film base. No stripping or emulsion skidding occurred when samples of the element were exposed and processed. The negatives produced had good definition and were readily scribed on the emulsion side to give clean lines, and the prints reproduced therefrom showed sharp, welldefined lines. -On storing the negatives for several weeks at relatively low humidity, no edge peeling of the emulsion from the film base was observed, and the prints made matched perfectly those prepared prior to storing. The tests indicated, accordingly, that the photographic element produced as above described was eminently suited for graphic arts and cartographic operations.

Example 2 surfaces with the following subbing composition, the proportions being given as percent by weight.

Percent Gelatin 1.75 Acetic acid- 1.00 Chrornic chloride (CrCl -6H O) 0.046 Cellulose nitrate 0.14 Acetone 10.0 Isopropyl alcohol 10.0 Acetonyl acetone 20.0 Water 3.5

Methylalcohol, sufiicient to make a total of 100% After drying, one of the coated surfaces was overcoated withan ordinary gelatino-silver halide emulsion and the other coated surface was overcoated with an aqueous gelatin solution containing no silver halide. On drying, the-element obtained showed no tendency to curl. It showed excellent physical characteristics and underwent all the tests without any indication of stripping or skidd spi h emuls l y r- Example 4 This example was carried exactly the same as Example 1, except that 5% by weight of butyl carbitol acetate was substituted for the mesityl oxide in the subbing composition. The photographic element obtained also showed satisfactory resistance to stripping and skidding of the emulsion under test conditions simulating actual intended use practices.

Example 5 This example was carried out exactly the same as Example 1, except that 5% by weight of a mixture of 25% acetophenone and 75% of a-methyl benzyl alcohol was substituted for the mesityl oxide. No stripping or skidding of the emulsion was observed under the test conditions which followed the processes generally employed in graphic arts and cartographic practices.

The invention further contemplates a subbing composition of the aforementioned kind modified by the addition of resins which in themselves will adhere to oriented polystyrene film base. Polybutyl methacrylate represents a resin ofthis kind. When added in a concentration of 50% of the weight of the gelatin employed it promotes bonding of the subbing layer to the film base. However, a greater amount of active solvent is required to cause it to dissolve to a homogeneous mixture. While at the higher concentrations of active solvents the adhesion appears to be excellent, the subbed base tends to be hazy and shows some crazing. Accordingly, only limited uses are contemplated for such subbed oriented polystyrene sheeting.

What is claimed is:

1. A coating composition for oriented polystyrene sheeting consisting essentially of 0.40-1.7S% by weight of gelatin, 0.032-0.140% by weight of cellulose, nitrate, 0.83.5% by weight of Water, -30% by weight of acetone, 10-30% by weight of isopropyl alcohol, -75% by weight of methyl alcohol, and 5-20% by weight of a higher boiling solvent selected from the group consisting of mesityl oxide, acetonyl acetone, butyl carbitol acetate,

' and a mixture of from 70-80% by weight of u-methyl benzyl alcohol and 30-20% by weight of acetophenone.

2. A coating composition according to claim 1, wherein the said higher boiling solvent is mesityl oxide.

3. A coating composition according to claim 1, wherein the said higher boiling solvent is acetonyl acetone.

4. A coating composition according to claim 1, wherein the said higher boiling solvent is butyl carbitol acetate.

5. A coating composition according to claim 1, wherein the said higher boiling solvent is a mixture of 70-80% by weight of a-methyl benzyl alcohol and 30-20% by weight of acetophenone.

6. An oriented polystyrene film base coated on at least one surface with a coating composition consisting essentially of 0.40-1.75 by weight of gelatin, 0.032-0.140% by weight of cellulose nitrate, 0.8-3.5 by weight of water, 10-30% by weight of acetone, 10-30% by weight of isopropyl alcohol, 15-75% by weight of methyl alcohol, and 5-20% by weight of a higher boiling solvent selected from the group consisting of mesityl oxide, acetonyl acetone, butyl carbitol acetate, and a mixture of from 7080% by weight of a-methyl benzyl alcohol and 30- by weight of acetophenone.

7. An oriented polystyrene film base coated on at least one surface with a coating composition according to claim 6, wherein the said higher boiling solvent is mesityl oxide.

8. An oriented polystyrene film base coated on at least one surface with a coating composition according to claim 6, wherein the said higher boiling solvent is acetonyl acetone.

9. An oriented polystyrene film base coated on at least one surface with a coating composition according to claim 6, wherein the said higher boiling solvent is butyl carbitol acetate.

, 6 10. An oriented "polystyrenefilm base coated on at least one surface with a coating composition according to claim 6, wherein the said higher boiling solvent is a mixture of 70-80% by weight of a-methyl'benzyl alcohol and'30-20% by weight of acetophenone.

11. A photographic element comprising an oriented polystyrene film base coated on at least one surface with a coating composition consisting essentially of 0.40-1.75% by weight of gelatin, 0.032-0.140% by weight of cellulose nitrate, 0.8-3.5 by weight of water, 10-30% by weight of acetone, 10-30% by weight of isopropyl alcohol, 15- 75 by weight of methyl alcohol, and 5-20% by weight of a higher boiling solvent selected from the group consisting of mesityl oxide, acetonyl acetone, butyl carbitol acetate, and a mixture of from 70-80% by weight of a-methyl benzyl alcohol and 30-20% by weight of acetophenone, and having a gelatino-silver halide emulsion layer coated directly over one of said coated surfaces of the said film base.

12. A photographic element comprising an oriented polystyrene film base coated on at least one surface with a coating composition according to claim 11 wherein the said higher boiling solvent is mesityl oxide, and having a gelatino-silver halide emulsion layer coated directly over one of said coated surfaces of said film base.

13. A photographic element comprising an oriented polystyrene film base coated on both surfaces with a coating composition consisting essentially of 0.40-1.75% by weight of gelatin, 0.032-0.140% by Weight of cellulose nitrate, 0.8-3.5 by weight of water, 10-30% by weight of acetone, 10-30% by weight of isopropyl alcohol, 15-75% by weight of methyl alcohol, and 5-20% by weight of a higher boiling solvent selected from the group consisting of mesityl oxide, acetonyl acetone, butyl carbitol acetate, and a mixture of from 70-80% by Weight of a-methyl benzyl alcohol and 30-20% by weight of acetophenone, and having a gelatino-silver halide emulsion layer coated directly over 7 one of said coated surfaces of said film base, and hav- 1 ing a non-sensitive gelatin composition coated directly over the other of said coated surfaces of said film base.

14. A photographic element comprising an oriented polystyrene film base coated on both surfaces with a coating composition according to claim 13, wherein the said higher boiling solvent is mesityl oxide, and having a gelatinio-silver halide emulsion layer coated directly over one of said coated surfaces of said film base, and having a non-sensitive gelatin composition coated directly over the other of said coated surfaces of said film base.

15. A photographic element comprising an oriented polystyrene film base coated on both surfaces with a coating composition according to claim 13, wherein the said higher boiling solvent is acetonyl acetone, and having a gelatino-silver halide emulsion layer coated di- 7 rectly over one of said coated surfaces of said film base, and having a non-sensitive gelatin composition coated directly over the other of said coated surfaces of said film base.

16. A photographic element comprising an oriented polystyrene film base coated on both surfaces with a coating composition according to claim 13, wherein the said higher boiling solvent is butyl carbitol acetate, and having a' gelatino-silver halide emulsion layer coated directly over one of said coated surfaces of said film base, and having a non-sensitive gelatin composition coated directly over the other of said coated surfaces of said film base. p

17. A photographic element comprising an oriented polystyrene film base coated on both surfaces with a coating composition according to claim 13, wherein the said higher boiling solvent is a mixture of 70-80% by weight of a-methyl benzyl alcohol and 30-20% by weight of acetophenone, and having a gelatino-silver halide emulsion layer coated directly over one of said 7 coated surfaces of said film base, and having a nonsensitive gelatin composition coated directly over the other of said coated surfaces ofsaid filrn base.

18. A process for preparing a photographic element comprising an oriented polystyrene as a film base which comprises coating both surfaces of said film base with a coating composition consisting essentially of GAO-1.75% by eight of gelatin, 0.032-O.140% by Weight of cellulose nitrate, Oil-3.5% by weight of Water, 1030% by weight of acetone, 10-30% by Weight of isopropyl alcohol, 15-75% by weight of methyl alcohol, and

540% by weight of a higher boiling solvent selected from the group consisting of mesityl oxide, acetonyl acetone, butyl carbitol acetate, and a mixture of from.

70-80% by Weight of ot-methyl benzyl alcohol and 30-20% by Weight of acetophenone, and subsequently coating a layer of gelatino-silver halide over one of said coated surfaces, and coating a non-sensitive gelatin composition over the other of said coated surfaces.

No references cited

Claims (1)

13. A PHOTOGRAPHIC ELEMENT COMPRISING AN ORIENTED POLYSTYRENE FILM BASE COATED ON BOTH SURFACES WITH A COATING COMPOSITION CONSISTING ESSENTIALLY OF 0.40-1.75% BY WEIGHT OF GELATIN, 0.032-0.140% BY WEIGHT OF CELLULOSE NITRATE, 0.8-3.5% BY WEIGHT OF WATER, 10-30% BY WEIGHT OF ACETONE, 10-30% BY WEIGHT OF ISOPROPYL ALCOHOL, 15-75% BY WEIGHT OF METHYL OXIDE, ACETONYL 5-20% BY WEIGHT OF A HIGHER BOILINGSOLVENT SELECTED FROM THE GROUP CONSISTING OF MESITYL OXIDE, ACETONYL ACETONE, BUTYL CARBITOL ACETATE, AND A MIXTURE OF FROM 70-80% BY WEIGHT OF A-METHYL BENZYL ALCOHOL AND 30-20% BY WEIGHT OF ACETOPHENONE, AND HAVING A GELARINO-SILVER HALIDE EMULSION LAYERCOATED DIRECTLY OVER ONE OF SAID COATED SURFACES OF SAID FILM BASE, AND HAVING A NON-SENSITIVE GELANTIN COMPOSITION COATED DIRECTLY OVER THE OTHER OF SAID COATED SURFACES OF SAID FILM BASE.

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