US3671248A

US3671248A - Stain inhibitor in photographic paper bases

Info

Publication number: US3671248A
Application number: US44965A
Authority: US
Inventors: Merle K Eldridge; Roy C Bloom; Douglas C Joseph
Original assignee: Eastman Kodak Co
Current assignee: Eastman Kodak Co
Priority date: 1970-06-10
Filing date: 1970-06-10
Publication date: 1972-06-20
Anticipated expiration: 1989-06-20
Also published as: FR2096123A5; GB1338639A; BE768363A; DE2128832A1; JPS5512584B1; DE2128832C2

Abstract

PHOTOGRAPHIC ELEMENTS HAVING POLYOLEFIN COATED PAPER SUPPORTS, PROVIDED WITH SILVER HALIDE EMULSION LAYERS CONTAINING SILVER HALIDE DEVELOPING AGENTS, WITH OR WITHOUT HYDROPHILIC BACKING LAYERS, EXHIBIT STAIN DUE TO MIGRATION OF THE DEVELOPING AGENT TO PAPER AND TO THE BACKING LAYER. STAIN IS AVOIDED BY SIZING THE PAPER WITH AN ALDEHYDE BISULFITE AND COATING ANY BACKING LAYER AT A PH LESS THEN 7 PREFERABLY ABOUT 3 TO 4.

Description

United States Patent Oflice 3,671,248 Patented June 20, 1972 3,671,248 STAIN INHIBITOR IN PHOTOGRAPHI PAPER BASES Merle K. Eldridge and Roy C. Bloom, Hilton, and Douglas C. *Joseph, Victor, ,N.Y., assignors to Eastman Kodak Company, Rochester, N.Y.

Filed June 10, 1970, Ser. No. 44,965 Int. Cl. G03c 1/48, N86

US. Cl. 96-76 R 7 Claims ABSTRACT or THE DISCLOSURE v This invention relates to light-sensitive photographic elements and more particularly to, a process for preventing discoloration thereof due to migration of developing agent from an emulsion layer to the support.

An element of particular use in photography comprises a polymer coated paper support provided with a silver halide emulsion layer and contiguous silver halide developing agent such as a polyhydric phenol, e.g. hydroquinone. It is observed that after storage of this paper, stain is visible particularly when viewing this paper from the side opposite the emulsion layer. We have unexpectedly discovered that this stain arises, during storage, from gradual migration of the developing agent from the emulsion through the relatively impervious underlying polymer layer to the paper fiber where it is oxidized to produce the observed stain.

Another element of use in photography comprises-a polymer coated paper support having a hydrophilic organic colloid backing layer, suchas an antistatic backing, on one surface and on the other surface a silver halide emulsion layer and contiguous silver halide developing agent such as hydroquinone. It has been found that immediately after coating and drying the emulsion layer on the support and winding in a roll, particularly when the emulsion layer contains the developing agent or it is in a layer on the emulsion surface, a pronounced brown stain at once appears in the organic colloid backing layer. We have discovered that this fresh stain arises from migration of the developing agent to the adjacent polymer surface when the paper is wound in the roll. In addition, more stain arises upon storage of the paper due to the mentioned migration of developing agent from the emulsion through the relatively impervious underlying polymer layer to the paper fiber.

In a further aspect of our invention we have discovered that this brown stain does not appear on fresh or aged polymer coated paper if the paper stock has been treated, for example coated or tub sized, with a composition containing a lower-aldehyde bisulfide so as to obtain at least about 30 milligrams per square foot. However, if the hydrophilic backing layer is present, it must be acidic having a pH less than 7 and preferably about 3 to 4, otherwise the stain still appears.

The accompanying drawing shows in greatly enlarged cross-sectional views representative photographic elements of our invention wherein in FIG. 1 layer 10 is ordinary photographic paper base sized with an aldehyde bisulfite and carrying extruded polyethylene layers 11 and emulsion layer 13 containing developing agent. No

stain arises on winding the paper in a roll or on ageing the paper. In the FIG. 2 element an antistatic layer of low pH is provided to avoid stain.

The polymer coated paper used in production of the sensitive photographic elements as illustrated in the drawing can be prepared by first tub sizing a photographic paper base of about 30 pounds per thousand square feet with an aqueous composition containing the aldehyde bisulfite, followed by coating or extruding polymer layers, e.g. polyester, polyolefin and the like, preferably a polyolefin layer, onto both surfaces of the paper. These polymers include polyolefins such as polyethylenes and polypropylenes and ethylene-propylene copolymers, polystyrene, polybutenes, polypentenes, polyacrylic acid esters, linear polyesters such as polyethylene terephthalates, polycarbonates, polyamides such as nylon, cellulolose esters, polyacrylonitrile, polyvinylidene chloride and other copolymers of the indicated monomers such as ethylenevinylacetate copolymers.

The paper can first be treated with corona discharge as described in US. Pat. 3,411,908 to facilitate adhesion of the polymer layers to the paper. About 8 pounds of polyethylene per thousand square foot of paper surface is useful for this purpose. When this polymer coated paper (FIG. 1) is activated, especially with controlled speed and corona frequency as disclosed in Ambusk, US. patent application Ser. No. 724,491, filed Apr. 26, 1968, now Pat. No. 3,549,406 and coated with the emulsion containing developing agent, no stain appears after winding in the roll or on storage of the paper. In another case (FIG. 2) when the polyethylene paper is coated at pH less than 7 with a hydrophilic organic colloid backing layer 12 such as gelatin, or a water-soluble cellulose ether or a cellulose ester, starch, etc., optionally containing an ionic antistatic agent, after emulsion coating of this paper stain is not visible after winding the paper in a roll even with the emulsion and antistatic layers in contact in the roll or on ageing the paper. A useful ionic antistatic composition includes an alkali metal salt of an alkylaryl polyether sulfonate or of a polymeric carboxylic acid, or a mixture thereof. In some cases it may be desirable to incorporate colloidal silica into the antistatic composition to obtain the desired antistatic properties. The above sulfonates are described in detail in US. Pat. 2,600,831, for example, the salt sold under the trade name of Triton X200 (p-[1,l,3,3 tetramethylbutyl]phenoxyethoxyethyl sodium sulfonate) sold by Du Pont de Nemours and Company. The polymeric carboxylic acids are illustrated by polymerized acrylic acids such as polyacrylic acid, polymethacrylic acid, and polyethacrylic acid such as Daxad 30 (trade name for the sodium salt of polymethacrylic acid) sold by Dewey and Almy Chemical Company. Many other alkali metal salts of polymeric carboxylic acids may also be utilized as the ionic organic antistatic agent, for example, potassium polyacrylatcs, alkali metal salts of acrylic acidmethyl acrylate copolymer, and the like. In addition, the sodium salt of cellulose sulfate can be used alone for the antistatic layer. A gelatin layer may separate layers 11 and 12 for controlling curl.

Useful developing agents for the emulsion layer include the polyhydric phenol silver halide developing agents such as hydroquinone, substituted hydroquinone, e.g. chlorohydroquinone, aminophenols, 3-pyrazolidones, catechol, substituted catechols, reductones, hydrazines and hydroxylamines. Mixtures of these developing agents are especially useful such as a mixture of hydroquinone and a 3-pyrazolidone, e.g. 50 to 200 milligrams hydroquinone per square foot and 0-20 miligrams 1-phenyl-3-pyrazolidone per square foot. If desired, the developed agent can also be made contiguous to the silver halide of the emulsion layer by being coated either in a subbing layer under the emulsion layer or in a layer.

The silver halide emulsions useful with this invention can comprise silver chloride, silver bromide, silver bromoiodide, silver chlorobromiodide or-mixtures thereof. The emulsions may be coarse or fine grained and can be prepared by any of the well-known procedures. Surface image emulsions or internal image emulsions may be used if desired. Regular grained emulsions may be used. The silver halide emulsion .grainsmay, in a particular coating, vary widely in grain size or mono-dispersed emulsions may be used. The emulsion used may comprise grains which have irregular crystal structures or they may be regular grained emulsions such as cubic gained emulsions. Negative type emulsions may be used or, if desired, direct positive emulsions may be used in the practice of the invention. The following examples will serve to illustrate the invention.

EXAMPLE 1 A photographic papersupport of about 30 pounds per thousand square foot is tub sized with the following compositions:

*Sodium formaldehyde bisulfite.

The sizing operations A, B and C yield coverages of about 125 milligrams, 62.5 milligrams and 3l.2 milligrams of the aldehyde bisulfite per square foot, respectively. At least about 30 milligrams per square foot is useful to produce the advantageous results mentioned below.

Thereafter, polyethylene is extruded onto the corona activated surfaces of the papers A, B, C and D at about 8 pounds per thousand square feet. The wireside of the polyethylene paper is then coronaactivated and coated with the following aqueous acidic antistatic composition, applying approximately 3 grarns/m. (dry weight).

Parts by wt. Starch 5.0 Daxad 30 5.0 Triton X200E 0.2 Water 85.9

Butyl alcohol pH 3.5 (adjusted with hydrochloric 4 acid) 4.0 The face side of the polyethylene coated paper is corona activated and coated with a gelatin-silver chlorobromoiodide emulsion containing hydroquinone and 1- phenyl-S-pyrazolidone so as to obtain about :125 milligrams hydroquinone and 6 milligrams 1-phenyl-3- pyrazolidone per square foot. It is observed that just after preparation of papers A, B, C and D as described above and winding in the roll, papers A, B and C viewed from the surface opposite the emulsion layer had high reflectivities (about 80% reflectance of light of wavelength 460 mm.) whereas the corresponding surface of paper D not containing SFB showed a pronounced brown stain (reflectance about 55% of 460 mm. light). Additional stain appears on D after storage. The papers A, B, ,C and D have structures essentially as shown in FIG. 2 of the aclayer. on top oftheemulsion.

companying-drawing is.-..t-he-..case. .of paper. D. thev stain. being visible on viewing from the side opposite layer 13.

Papers A, B, C and D are exposed to black-and-white images and processed by use of an alkaline activator solution to initiate silver halide development followed by fixing and washing. As a result; papers-A", B and showed no stain in the highlights of the images or on the rear surface wh'ereas some stain is still visible-on the'corresponding surfaces of paper D not containing the SFB.

' EXAMPLE -2 The processes of Examples 1A and are carried out except omitting the antistatic layer (FIG. 1). As a result,

followed by extrusion or solvent coating ofpolymer layers on each paper surface. If desired, White pigment can be incorporated into the polymer layer under the emulsion layer. The polyethylene layers can be replaced with other polymeric layers including cellulose ester and linear polyesters. Similarly, other antistatic agents and hydrophilic.

organic colloid carriers may comprise the acidic backing layer.

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

What we claim is:

1. A light-sensitive photographic element comprising a paper support treated with a lower aldehyde bisulfite, eX-' truded polymer layers on each surface 'of the paper,-a silver halide emulsion layer and contiguous silver halide developing agent adhered to thesurface of one of the polymer layers, and a hydrophilic organic colloid layer having a. pH less'than 7 adhered to the surface of the other polymer layer.-

2. The element according to claim 1 wherein'the polymer layers contain-a polyolefin or olefin copolymer.

3. The element according to claim 1 wherein the aldehyde bisulfite is sodium formaldehyde bisulfite and the veloping agent is hydroquinone.

developing agent'is a polyhydric phenol contained in the emulsion layer. 4. The element according to claim 1 wherein the hydro.-

philic organic colloid layer is an antistatic layer contain-.- a ing an alkali metal salt of an alkylaryl polyether sulfonate' or of a polymeric carboxylic acid, or a mixture thereof.

5. The element according to claim 1 wherein the developing agent is a polyhydric phenol.

6. The element according to claim '1 7. The element according to claim 1 wherein the developing agent is a mixture of hydroquinone and a 3-- pyrazolidone.

' a References Cited UNITED STATES'PATENTS 3,212,895

wherein the de-