DE2011649A1 - Antistatic photographic material - Google Patents

Abstract

Antistatic photographic material has a silver halide emulsion layer and an antistatic layer consisting of a mixture or graft copolymer contg. (I) a polymer of olefinically unsatd. monomers contg. sulpho groups of m. wt. >=10,000, and (II) a polymer of m. wt. of >=10,000 contg. at least 50 mole % COOH-contg. monomers in free or neutralized form.

Description

Improved Photographic Materials The present invention relates to photographic materials with improved antistatic sizes.

Due to the accumulation of electrical charges on photographic Films are great both in their manufacture and in their use Trouble. These static electrical charges can, for example, be caused by friction of the film on the rollers or other parts of the device through which the film runs through it or caused by contact with rough surfaces. By static discharges, the film is exposed. This occurs after the photographic Processing irregular stripes, lines or dark spots. The appearance static charges on processed films, especially those for cinematography certain films, are also undesirable because they create friction as they pass through of the film is increased through the picture window or other parts of the projection device will.

This can reduce the electrostatic charge on the film surfaces be that you add matting agents to the protective layers, the adhesion of two films on top of one another. Once a charge has occurred, it can be continue to remove with electrically conductive additives. You can do both combine.

In order to avoid these difficulties, a conductive one is usually used or hygroscopic material applied to the surface of the film so as to to increase the electrical conductivity of the film. Many effective in this regard Substances are however photographically not inert, so that a Deterioration in photographic properties occurs.

Quaternary salts are usually not in photographic materials usable because they create veils. Hygroscopic substances such as glycerine, potassium acetate or LiOl lead to sticking of the layers and are at low humidity ineffective. Higher molecular weight carboxylic or sulphonic acids, such as polystyrenesulphonic acid Sodium and sodium polyvinyl sulfonic acid point directly to a hydrophobic layer support brought a good antistatic effect, when used in gelatin or emulsion layers however, this effect is greatly reduced. Chromium complexes react with the gelatin and can therefore only be used under certain conditions.

Many compounds that have a good antistatic effect, change the casting properties of the casting solutions when added to gelatin solutions, so that irregular layer surfaces arise.

The invention is based on the object of finding antistatic agents which are photographically inactive and which can be used alone or in admixture with gelatin are.

A photographic material having at least one silver halide emulsion layer has now been obtained found, which has an antistatic layer, in this layer as an antistatic in the form of a mixture or of a graft polymer I) an olefinic polymer unsaturated monomers with a molecular weight of at least 10,000, the at least Contains 40 mol. Sulfosubstituierte N-Shenylmalinimide in polymerized form and II) a polymer with a molecular weight of at least 10,000, the one containing carboxyl groups Monomers in free or neutralized form in amounts of at least 50 mol. In polymerized contains.

The mixture of the carboxyl and sulfonic acid group-containing polymers can be achieved in a simple manner by mixing the two polymers in the desired Quantities are produced. However, it is also possible to use one polymer component in the presence of the others, e.g. by sulfonation or saponification reactions or by polymerization reactions, in the latter case also partly Graft polymers can arise. A cheap way of working is best in that carboxyl group-containing polymers directly in the aqueous solution of the sulfonic acid group-containing Polymerizats, preferably by radical polymerization to produce, wobai the occurrence of graft reactions is possible.

The weight ratio of carboxyl group-containing polymer to Polymer containing sulfonic acid groups can vary within wide limits. In general, weight ratios of 1:10 to 10: 1 are sufficient. As special Mixtures with a weight ratio between 1: 3 and 3: 1 have proven favorable.

The polymers can be in dispersions or emulsion form or in Form of their solutions in suitable solvents, especially in water or methanol be applied. They can be completely or partially neutralized. The pH should preferably be between 4 and 8.5.

The polymers containing carbonyl groups are preferably direct or in the form of their salts - water-soluble homo- and copolymers based on Itakon-, Maleic, Fuma, methacrylic acid, but especially based on acrylic acid, preference is given to the homopolymers.

In the case of copolymers, the ComQnom.eTen are predominantly hydrophilic consider such as short-chain vinyl filters, e.g. Vinyl acetate or derivatives of acrylic --- or Methacrylic acid such as amides or short-chain esters, especially hydrophilic groups such as hydroxyl group-containing esters, e.g., oxypropyl methacrylate, allyl compounds such as trimethylolpropane monoalkyl ethers. Other comonomers are of course also possible suitable as long as they are contained in such small amounts that the water solubility of the copolymer is retained in the form of the salt. Such monomers are olefins like ethylene or propylene, styrene vinyl chloride longer Acrylic ester such as butyl acrylate, decyl methacrylate, acrylonitrile and the like.

The copolymers preferably containing water-soluble carboxyl groups or the preferred homopolymers should have molecular weights above 10,000, preferably from 50,000 to 1,000,000, although higher molecular weights can also be used but due to the high viscosity of their solutions, certain technical difficulties.

As polymers containing sulfonic acid, preference is given to copolymers: 3rd suitable to 40-60 mol from units of sulfo-substituted N-phenylmaleimides exist and which have a molecular weight between 50,000 and 70,000. With these Copolymers are suitable as comonomers, for example: polymerizable olefinically unsaturated Aliphatics with up to 5 carbon atoms, e.g. ethylene, propylene, butylene, 2-methylpentene-1 or isoprene, also vinyl alcohol, vinyl esters with aliphatic carboxylic acids up to 5 carbon atoms, e.g. vinyl acetate, vinyl propionate or vinyl butyrate, vinyl ether, where the ether component is aliphatic and contains up to 5 carbon atoms, e.g. vinyl isobutyl ether, also styrene or substituted styrenes, e.g. styrenes containing sulfo groups. Copolymers of ethylene, isobutylene and / or styrenes are particularly suitable with sulfo-substituted N-phenylmaleimides.

Some preferred suitable sulfo group-containing polymers with idealized formulas and an average molecular weight are given below: The polymers containing sulfo groups are accessible in various ways belonging to the prior art, preferably by reacting maleic anhydride copolymers with corresponding aromatic aminosulfonic acids or their alkali salts in an aqueous or non-aqueous medium at temperatures above 1200 ° C., the maleic acid imide ring being formed with the escape of water. The polymers can also be prepared by sulfonating copolymers of N-phenylmaleimide, which are tough either by copolymerization of N-phenylmaleimide or subsequent reaction of maleic anhydride copolymers with aniline with imidation.

The production of some polymers is given below by way of example described; the parts given are parts by weight: Polymer I: In 17,000 Parts of H20 are 600 parts of XaOH and 4,500 parts of aniline-3,4-disulfonic acid monopotassium as solved. 3,000 parts of an approximately alternating maleic anhydride-styrene copolymer are then used with a t-value of sun 0.56 measured in dimethylformamide at 2500 (molar weight na.

100,000) and heated in the autoclave to 17500 for 10 hours, whereby a clear solution of the polymer I is formed.

Polymer II: The procedure is the same as for polymer I, only used an approximately alternating maleic anhydride-styrene copolymer with a t-value of 1.5 (molar weight approx.

2,500,000).

Polymer derivative 111: 300 parts of aniline-3,5-disulfonic acid monopotassium salt and 40 parts of NaOH are dissolved in 900 parts of water and alternating with 130 parts of one built-up ethylene-maleic anhydride copolymer voa value 0.91 (molar weight approx. 50,000).

The mixture is then heated to 1700 ° C. for 10 hours and a clear solution is obtained of the polymer III.

Polymer IV: 300 parts of aniline-3,5-disulfonic acid monopotassium salt and 40 parts of NaOH are dissolved in 1500 parts of water. Then 152 pieces are placed isobutylene-maleic anhydride copolymer with a value of approximately alternating 0.7 (molar weight about 65,000) and heated to 175 ° C for 10 hours, with a clear solution of the polymer IV is formed.

Polymer V: In 300 parts by volume of dry SO2 at -600C 10 parts of dry liquid SO3 dissolved. Then stir well 20.2 parts of alternating styrene-maleic anhydride copolymer entered. One stirs 8 hours at approx. 500C and then allowed to evaporate. Then the so obtained, Polymer sulfonated in the aromatic nucleus with 8 parts of NaOH and 17.4 parts of sulfanilic acid dissolved in 140 parts of water and heated to 17,500 for 10 hours, during which the impurity accomplishes. A clear solution of the polymer V is obtained.

Polymer VI: 80 parts of NaOE and 346 are dissolved in 3300 parts of water Parts sulfanilic acid. 400 parts of equimolar styrene-maleic anhydride copolymer are then stirred into this solution. m value 0.62, and heated in the autoclave to 170 ° C for 10 hours. You get a clear approx. 20 fig. solution of the polymeric imide.

Polymer VII: The procedure is as for polymer VI, one uses only the corresponding metasulfonic acid instead of the sulfanilic acid.

The polymers are preferably completely imidized. In principle suitable however, there are also corresponding polymers which, to a small extent, contain maleic acid or maleic anhydride units or the hemiamide.

The occurrence of such saponification products can also be found in the The above-described production in an aqueous medium cannot always be excluded with certainty, so that the above formula is only to be regarded as an approximation formula and for the whole of the polymer molecule is sometimes not strictly applicable.

The preparation of the antistatic agents to be used according to the invention Mixtures of carboxyl groups and polymers containing sulfonic acid groups is said Described below by way of example: Mixture 1: In a 15 point aqueous solution polymer I dissolves as much polyacrylic acid (molar weight approx. 90,000) at 6500, that the resulting mixture has a solid content after neutralization with NaOH to pH 6.5 of 30.

Mixture 2: As Mixture 1, but instead of Polymer I is now Polymer VI (molar weight 150,000) is used.

Mixture 3: Like mixture 1, except that instead of polyacrylic acid, a Copolymer of 90 parts of methacrylic acid and 10 parts of oxypropyl methacrylate (molar weight approx. 100,000) are used.

Mixture 4: 7500 parts of 15% aqueous solution of polymer (molar weight approx. 80,000) are stirred with 1275 parts of acrylic acid at 40.degree. C. and then set 6 parts of potassium persulfate and 3 parts of sodium pyrosulfite. The polymerization temperature is kept at a maximum of 50 ° C. The polymerization is complete after about 15 hours and the material after neutralization with 30 liters of NaOH to a pH of 6.5 usable. The substance content is 30.

Mixture 5: As mixture 4, only the polymer VI is now mixed with a Mol weight of about 160,000 used.

Mixture 6: As mixture 4, only 640 parts of acrylic acid are used. The solids content is about 22% after adjusting to pH 6.5.

The polymers to be used according to the invention as antistatic agents or polymer mixtures can be clear or cloudy solutions or dispersions. They are photographically inert, so that no negative influence on the photosensitive Layers occurs.

It is possible with the polymers by adding them to gelatin solutions or the casting solutions for the silver halide gelatin emulsions, in a simple manner pour smooth, non-sticky layers. The antistatic effect is extraordinary high, as demonstrated in the examples below.

The polymers are in the form of aqueous solutions with a solids content up to 15% by weight, preferably 2-4%, processed so that layers with a dry layer thickness of 1.5 - 2 µ arise. The conductivity depends on the layer thickness; at the thickness mentioned ensures sufficient conductivity. The mentioned Compounds have layer-forming properties. You can go alone or with Additions of water-permeable layer colloids, e.g. Gelatin, used; the content of layer colloids can optionally up to 10 times the amount of the antistatic, but preferably not more than 20% (based on on the dry weights).

The layers according to the invention can be surface-active as auxiliaries Substances such as anionic or non-ionic wetting agents or anti-Newton additives, e.g. 1 - 5 / u large particles of polystyrene, polymethacrylic acid esters or urea-formaldehyde condensates, or SiO2 can be added. This gives Nan smooth layers of eye-sight Antistatic effect.

The layers according to the invention are used in the customary manner as protective layers applied to the top of the layer structure and can be used for black and white and color photographic materials. In principle, these can have anti-static layers however, can be arranged at any point in the layer structure, both on the emulsion side as well as on the back side directly on the carrier or in the Emulsion itself.

The test for antistatic effectiveness takes place after two days Air conditioning of the sample strips with the rotating electrostatic field strength meter Type FM 300 - NR I according to Prof. Dr. Ing.F Schwenckhagen (manufacturer: Bergischer Feingerätebau, Wuppertal). The level of charge was measured at 60 g relative humidity. The surface resistance is determined with a measuring device from Lindenblatt, Electrical engineering and electronics, 'Berlin-Halensee. The device has two at a distance 2 cm parallel, 10 cm long comb electrodes against which the sufficient conditioned samples are pressed with constant pressure. The resistances will read on a terra ohmmeter connected to it.

Example 1 In a protective layer for photographic materials, which contains 20 g of gelatin per liter of water, half of the gelatin was successively replaced by antistatic agents A to I.

For a good casting quality, -12 ml of wetting agent were added per liter of solution. The casting thickness was 1.5 / u, measurements were made as indicated above.

Example 2 To a silver halide photographic emulsion containing about 60 g of gelatin and 35 g of AgBr, which contains panchromatic sensitizers for black and white photography, wetting agents, stabilizers, etc., 20 g of antistatic agents A to I are added per liter of emulsion. Measurements as in 1.

Claims (5)

Patent Claims 1) Photographic material having at least one silver halide emulsion layer, which contains an antistatic layer, characterized in that the antistatic Layer in the form of a mixture or graft polymer I) a polymer of olefinically unsaturated monomers with a molecular weight of at least 10,000 that at least 40 mol% of sulfo-substituted N-phenylmaleimides in polymerized form contains and II) a polymer with a molecular weight of at least 10,000, the carboxyl group-containing Monomers in free or neutralized form in amounts of at least 50 mol .- * contains polymerized. 2) Photographic material according to claim 1, characterized in that that the antistatic layer is gelatin as an additional, hydrophilic binder contains. 3) Photographic material according to claim 1, characterized in that that the weight ratio of the carboxyl-containing polymer to the sulfonic acid-containing Polymer is 1:10 to 10 * 1. 4) Photographic material according to claim 1, characterized in that that the carboxyl group-containing polymer is polymethacrylic acid or polyacrylic acid is included. 5) Photographic material according to claim 4, characterized in that that a copolymer is contained as the polymer containing sulfonic acid groups, which consists essentially of styrene and N-4-sulfophenylmaleimide units.