US3769020A

US3769020A - Photographic material with improved properties

Info

Publication number: US3769020A
Application number: US00114666A
Authority: US
Inventors: W Verburg
Original assignee: Agfa Gevaert AG
Current assignee: Agfa Gevaert AG
Priority date: 1971-02-11
Filing date: 1971-02-11
Publication date: 1973-10-30
Anticipated expiration: 1990-10-30

Abstract

A photographic material is provided having a layer support backed on both sides with polyolefine and having at least one layer of a light sensitive silver halide gelatine emulsion layer thereon. The rear surface of the support having thereon a water impermeable layer containing a major proportion of a water insoluble binder and minor proportions of an antistatic agent and an inorganic or organic matting agent.

Description

Uited States Patent Vet-burg Oct. 30, 1973 [54] PHOTOGRAPH: MATERIAL WITH 3,399,995 9/1968 Winchell 96/87 A KMPROVED E'ROPERTIES FOREIGN PATENTS OR APPLICATIONS Inventor: Werner g, Carl-Rumpff, 815,662 7/1959 Great Britain 96/87 A Germany [73] Assignee: AGFA-Gevaert Aktiengesellschaft, Primary Exami"e" Rnald Smith Leverkusen Germany Attorney-Walter C. Kehm, Samson B. Leavitt and Morton Friedman [22] Filed: Feb. 11, 1971 [21] Appl. No.: 114,666 [57] ABSTRACT A photographic material is provided having a layer 52 us. c1. 96/85, 96/87 A pp backed on both Sides with Polyolefine and [51] 03 1 32 having at least one layer of a light sensitive silver ha- [58] Field of Search 96/87 A, 85 gelatine emulsion layer thereon- The rear Surface of the support having thereon a water impermeable [56] References Cited layer containinga major proportion of a water insolu- UNTED STATES PATENTS ble binder and minor proportions of an antistatic 3 525 621 8/1970 M11 9 A X agent and an inorganic or organic matting agent.

1 er 2,725,297 11/1955 Morey 96/87 A 7 Claims, No Drawings PHOTOGRAPHIC MATERIAL WITH IMPROVED PROPERTIES The invention relates to a photographic material having a polyolefme backed layer support the rear surface of which carries an antistatic layer and which is easier to write on.

It is known to use polyolefine backed sheets, especially polyolefine backed paper, as layer supports for photographicmaterials which contain light sensitive silver halide emulsion layers. The main advantage of these polyolefine backed materials over simple supports such as paper alone is that they absorb much less of the aqueous photographic baths in the course of processing so that both the amount of chemicals used and the treatment time are reduced. Polyolefine backed supports, and especially supports which are backed with polyethylene have, however, certain disadvantages, the main disadvantages being that they become electrically charged much more readily and that the rear surface of the support is much more difficult to write on than paper supports. To overcome these disadvantages, polyethylene backed paper used for photographic purposes is treated with antistatic layers and with auxiliary layers which are intended to improve the writing surface. The known methods used for improving the tendency of these layer supports not to become charged have, however, not provided satisfactory results. This is mainly due to the fact that the choice of antistatic agents which are photographically inert is relatively small. Thus there are no sufficiently effective antistatic agents which can be incorporated into the polyethylene layer without exerting an adverse effect on the photographic layers. Other antistatic agents which are compatible with silver halide emulsion layers, however, are washed out to a considerable extent in the course of processing so that the antistatic effect is severely reduced in the processed material. For this reason, attempts have also been made to arrange the antistatic layer between the support and the polyethylene layer, but the effect of layers arranged in this way is generally not sufficient.

lt is among the objects of the invention to modify polyolefme backed supports for-photographic materials so that their tendency to become electrostatically charged will be reduced and at the same time their quality as a writing surface will be improved.

A photographic material comprising a layer support which is backed with polyolefine on both sides and comprising at least one light sensitive silver halide gelatine emulsion layer has now been found in which a water impermeable layer is applied to the rear surface of the layer support in a thickness of 0.5 to ID microns, which water-impermeable layer contains at least 70 percent by weight of a water-insoluble binder, 5 to 25 percent by weight of an antistatic agent and l to percent by weight of an inorganic or organic matting agent, based on the total weight of the dry layer.

Suitable binders for the back'coating in the material according to the invention are water-insoluble synthetic polymers or copolymers. Copolymers which contain (l) a polymerizable olefine in particular ethylene, (2) a half-ester of an a, B-unsaturated carboxylic acid in which the alcohol component is preferably aliphatic or cycloaliphatic and contains up 'to eight carbon atoms, preferably a maleic acid half-ester, (3) vinyl chloride and (4) a vinyl ester of a saturated carboxylic acid, preferably of an aliphatic carboxylic acid containing up to five carbon atoms have been found to be particularly suitable. The proportion of the components in the copolymer may vary within wide limits. Copolymers of the following composition are especially advantageous:

9 30 percent weight of a polymerizable olefine in particular ethylene 2 12 percent by weight of a half-ester of dicarboxylic acid and 58 percent by weight of a mixture of vinyl chloride and the vinyl ester in which the proportion of the vinyl ester is 15 to 45 percent by weight of the mixture.

' The copolymers used according to the invention preferably have an average molecular weight of between 20,000 and 100,000. They should be free from low molecular weight constituents. They are particularly easy to use in the form of an aqueous dispersion. The polymer latices have a particle size of less than 0.5 microns.

The matting agents may be either organic or inorganic substances. Suitable organic substances are e.g., polyacrylonitrile dispersions; these must be heterogeneously dispersed in the layer. Inorganic matting agents are especially suitable, e.g., silicic acid or silicates and especially aluminium oxides, if desired in the form of their oxihydrates.

Suitable polyolefine backed supportsare e.g., those which contain polyethylene or polypropylene layers. Polyethylene backed paper is preferred.

In principle, a wide variety of antistatic agents may be used for the layers in the material according to the invention. The choice ofa suitable antistatic agent will depend on-the properties required of the layer. according to the invention. Thefirst requirement, of course, is that the antistatic agents should be photographically inert so that they will not have an adverse effect on the light sensitive photographic layers with which they come into contact. Polystyrene sulphonic acid and its derivatives have been found to be especially useful for this purpose. Suitable products of this type have been described in German Pat. No. 912,778. Spirocyclic .organic phosphoric acid esters are also quite suitable, e.g., those mentioned in U.S. Pat. No. 3,428,456.

An excellent antistatic effect and an excellent writing surface at the back of the photographic material are achieved with the layers according to the invention. The material according to the invention fully meets the requirements in practice as regards both these properties. The antistatic properties and hence the surface resistance of the material are adequately preserved even after the photographic processing.

At the same time, the rear surface can be easily and clearly imprinted with the usual printing dyes such as those used in stamping pads or in automatic printing mechanisms in photographic processing apparatus or the dyes used in typewriter ribbons or with ordinary pencils. The writing produced on these surfaces is resistant to the photographic baths and is still clearly legible after the photographic process. This is very important when automatic apparatus is used for processing because in that case information is written on the back of the exposed photographic material to note the filter values in the case of colour photographic copies or reference numbers or other data of the client.

The rear coating layers according to the invention are applied bythe usual methods of dipping, spraying or wiper application. A preliminary treatment such as exposure to corona discharge according to Deutsche Auslegeschrift No. 1,159,159 isadvisable to obtain better bonding of these coatings. The coatings are advantageously produced by mixing aqueous solutions or dispersions of the components and applying them to the polyoleiine backed material from the aqueous medium. After the rear coating according to the invention has been applied, the light sensitive photographic silver halide emulsion layers and auxiliary layers may be applied to the other side of the layer support.

The rear coating is suitable both for black and white materials and for colour photographic materials and especially for the latter.

The properties of the photographic layer are not disadvantageously affected by the rear coating.

The binder for the rear coatings may, of course, consist of a mixture of various polymers. According to one advantageous embodiment, the layer may contain ionic polyurethanes in addition to the copolymers mentioned above, especially anionic polyurethanes of the type described in US. Pat. No. 3,297,989. Small quantities of hydrophilic binders such as gelatine may also be added to the layers.- When using the copolymer mentioned above which has been described in Belgian Pat. No. 741,338 up to 30% by weight of other binders, based on the total weight of binder, may be used, such as the anionic polyurethanes mentioned above or gelatine.

Example 1 A rear coating of the following casting solution is applied to a layer support of paper which has been backed on both sides with polyethylene:

1 liter of a percent aqueous solution of polystyrene sulphonic acid (molecular weight 40,000, sulphonic acid group content 50 to 80 percent based on 1 mol of styrene); I

liter of a 50 percent polymer latex of a copolymer having the following composition:

18.2 percent by weight of vinyl acetate 63.2 percent by weight of vinyl chloride 15.3 percent by weight oflethylene and 3.3 percent by weight of the cyclohexyl half-ester of maleic acid, and i 10 g ofa commercial aluminium silicate, e.g., the aluminium silicate sold by Farbenfabriken Bayer AG. under the name Baysikal.

The rear coating is applied with a conventional roller applicator. The thickness of the dried layer is 2 microns.

A bonding layer is first applied to the other side of the layer support to improve the bond between the polyethylene and the hydrophilic photographic layers, and this is then coated with an ordinary silver halide gelatine emulsion layer used for black and white copying material.

The photographic material is exposed and figures and letters are then written on the back with the usual instrument using a typewriting ribbon. The material is then developed, fixed and dried in known manner.

After the photographic processing, the letters and numerals are clearly legible.

Measurements of the conductivity of the rear coating before and after processing indicate that the conductivity is sufficiently high to prevent troublesome accumucourse of the process. The surface resistance of the unconverted polyethylene layer is 10 ohm.

EXAMPLE 2 A rear coating of the following casting solution is applied to a layer support which has been backed with polyethylene on both sides:

1 liter of a 10 percent aqueous. solution of polystyrene sulphonic acid (molecular weight 40,000 to 80,000, sulphonic acid group content 50 to percent based on 1 mol of styrene),

0.8 liter ofa 50 percent aqueous latex of the following copolymer:

32.6 percent by weight of vinyl acetate 47.5 percent by weight of vinyl chloride 14.0 percent of ethylene 5.5 percent by weight of the cyclohexyl half-ester of maleic acid Latex solids content: 59 percent,

0.2 liter of a 30 percent aqueous dispersion of an anionic polyurethane according to US. Pat. No. 3,428,456 (the polyurethane is a poly-addition product of 218.5 g of the polyester of adipic acid, hexanediol and neopentyl glycol (OH number 63), 32.6 g of hexane-1,6-diisocyanate and 46 g of a 20 percent aqueous solution of sodium aminoethane sulphonate, and

8 g of aluminium hydroxide.

The layer has a thickness of 3 microns when dry. A layer of this composition has practically the same good qualities when applied to a support which has been coated with polypropylene.

The usual layers for a multilayered colour photographic material are applied to the other side of the layer support. These layers comprise a blue sensitive silver halide emulsion. layer which contains yellow coupler, a yellow filter layer, a green sensitive silver halide emulsion layer containing a magenta coupler and a red sensitive silver halide emulsion layer containing a cyan coupler.

The layers are processed as indicated in Example 1.

Before processing, the rear coating has a surface resistance of 10 ohm and after processing a surface resistance of 10 ohm. The rear coating is a good writing surface. The writing on it is resistant to the processing baths.

Similar advantages are obtained with rear coatings applied from casting solutions of the following composition:

1.2 liter of a 10 percent polystyrene sulfonic acid solution 0.9 liter of the copolymer latex of Example 1 0.3 liter of the polyurethane dispersion of Example 2 5 g of aluminium hydroxide 5 g of aluminium silicate 0.2 of saponin as wetting agent in the form of a 5 percent aqueous solution. 2.

Same composition as above, but instead of aluminium hydroxide/aluminium silicate mentioned there as matting agent, 0.01 of a 12 percent aqueous dispersion of polyacrylonitrile (molecular weight about 100,000) is used.

I claim:

1. A photographic material comprising a layer support which is backed with polyolefine on both sides and at least one light sensitive silver halide gelatine emulsion layer, characterised in that a water impermeable layer having a thickness of 0.5 to microns is applied to the rear surface of the layer support, said layer containing at least 70 percent by weight of a waterinsoluble binder, said binder comprising a copolymer of ethylene, a half-ester of an a,B-unsaturated carboxylic acid, vinyl chloride and a vinyl ester of a saturated carboxylic acid, 5 to 25 percent by weight of an antistatic agent and l to 10 percent by weight of an inorganic or organic matting agent, based on the total weight of the dry layer.

2. A photograhic material according to claim 1, characterised in that it contains, as the layer support, paper which has been backed with polyethylene on both sides.

3. A photographic material according to claim 1, characterised in that the binder has the following composition:

9 to 30 percent by weight of ethylene 2 to 12 percent by weight of a half-ester of the dicarboxylic acid to 58 percent by weight of a mixture of vinyl chloride and the vinyl ester, the proportion of the latter being 15 to 45 percent by weight of this mixture.

4. A photographic material according to claim 1, wherein the matting agent is an insoluble inorganic aluminum compound.

5. A photographic materialaccording to claim 4, wherein the matting. agent is aluminum hydroxide or aluminum silicate.

6. A photographic material according to claim 1, wherein the antistatic agent is polystyrene sulphonic acid.

7. A photographic material as defined in claim 1 wherein said half-ester of an a,,B-unsaturated carboxylic acid is the cyclohexyl half-ester of maleic acid and wherein said vinyl ester of a saturated carboxylic acid is vinyl acetate.

Claims

2. A photograhic material according to claim 1, characterised in that it contains, as the layer support, paper which has been backed with polyethylene on both sides.
3. A photographic material according to claim 1, characterised in that the binder has the following composition: 9 to 30 percent by weight of ethylene 2 to 12 percent by weight of a half-ester of the dicarboxylic acid 90 to 58 percent by weight of a mixture of vinyl chloride and the vinyl ester, the proportion of thE latter being 15 to 45 percent by weight of this mixture.
4. A photographic material according to claim 1, wherein the matting agent is an insoluble inorganic aluminum compound.
5. A photographic material according to claim 4, wherein the matting agent is aluminum hydroxide or aluminum silicate.
6. A photographic material according to claim 1, wherein the antistatic agent is polystyrene sulphonic acid.
7. A photographic material as defined in claim 1 wherein said half-ester of an Alpha , Beta -unsaturated carboxylic acid is the cyclohexyl half-ester of maleic acid and wherein said vinyl ester of a saturated carboxylic acid is vinyl acetate.