GB2046626A - Polyester support for use in photography - Google Patents

Abstract

A polyester support for use in photography is provided, on at least one surface thereof with a layer containing a copolymer which comprises a) 60 to 90% by weight of at least one monomer selected from glycidyl methacrylate and glycidyl acrylate (first component), b) 10 to 40% by weight of at least one diolefin monomer (second component), and c) 0 to 30% by weight of a vinyl monomer (third component). The presence of the copolymer layer leads to improved adhesion of photosensitive emulsion layers to the support and a reduced tendency to "edge stripping".

Description

SPECIFICATION Polyester support for use in photography This invention relates to a photographic polyester support having a sub layer, more particularly, to the polyester support improved in adhesion to a hydrophilic colloid as a binder of a light-sensitive photographic material constituting layer.

The polyester support whose representative example is polyesthylene terephthalate is used for the light-sensitive photographic material, which has hydrophobic surface and does not adhere well directly to a photographic hydrophilic layer.

It is required to bring about strong adhesion under various conditions including a variety of treatments applied to the light-sensitive photographic material in the dry state before and after development, wet state during development. Further, it is required to strongly adhere under various conditions as mentioned above to the polyester support a variety of layers as the photographic hydrophilic layer, such as silver halide emulsion layers having various compositions, an anti-halation layer, a backing layer for inhibiting curling, a second sub layer and the like, which contain gelatin or other natural or synthetic polymer as a binder.

In order to keep satisfactorily strong adhesion, it is ordinarily effected to apply a sub layer containing certain polymer before the photographic hydrophilic layers are applied thereon.

The polyester support is formed by effecting two kinds of stretching, namely monoaxial stretching and a biaxial stretching which is effected vertically to the monoaxial stretching thereafter. Such subbing process is usually carried out during the course of film-forming of the polyester support, i.e. before the monoaxial stretching, after monoaxial stretching and/or after biaxial stretching and heat set. The subbing process effected before monoaxial stretching or between monoaxial stretching and biaxial stretching is carried out under different process conditions from those where the subbing process after both of biaxial stretching and heat set is effected.

In the former case, particularly in case that the process is effected before the monoaxial stretching, the resin used for the subbing is very limited because a resin tends to withstand the stretch and heat set treatment which are carried out after the subbing process. As this type, there are known the process using as the resin for subbing a copolymer containing vinyl chloride and/or vinylidene chloride as described in U.S. Patent 2,852,378; 3,586,508; 3,630,741; 2,627,088 or 2,698, 235; Japanese Patent Pre-Exam.Publication No. 51-135991; Japanese Patent Publication No. 52-48312; Belgian Patent 721,469 or 742,769 and the process using as the resin for subbing a vinyl halogeno ester-containing copolymer alone or in combination with a vinyl chloride and/or vinylidene chloride-containing copolymer as described in British Patents 1208821 and 1141395. However, each of the above processes makes it unable to recover or re-use the polyester support after completion of the subbing process because halogens are contained in the resin for subbing used in each process. Furthermore, the above processes show such defects that a harmful halogen gas is emitted on burning up of waste base.As the example where a resin for subbing free from halogens is used as the resin for subbing, there is known the process using a copolymer which contains diolefin monomers described in Japanese Patent Pre-Exam. Publication No. 52-65422, No.

52-96016 or No. 52-108114. The photographic polyester support prepared by each of these subbing processes shows satisfactory adhesive strength to the gelatin-silver halide emulsion layer, but only unsatisfactory adhesive strength to the gelatin backing layer.

On the other hand, in the subbing process for the polyester support after biaxial stretch and heat set, it is necessary to subject the surface of the polyester support to some kind of treatment at the subbing process, because molecules on the surface of the polyester support are oriented to crystallize and thus the surface is made too stable both chemically and physically to be subbed easily. Usually, after completion of surface treatment to the polyester support by means of acid treatment, flame treatment, corona discharge treatment, plasma treatment, UV treatment or pre-treatment with a swelling agent, either an aqueous dispersion sub solution containing dispersed therein a resin for subbing is coated and then dried, or a sub solution comprising an organic solvent or one in which a swelling agent for the polyester support is included is coated and then dried.

Alternatively, the above-mentioned subbing processes are combined. Particularly, in these days, because of pollution problem, such subbing process that does not use any organic solvent or a swelling agent for the polyester support have been required.

As an example, there is known the subbing process where a copolymer comprising as the monomer constituting element the diolefin as described in Japanese Patent Publication No. 48-3564 and British Patent 1,278,924 and an acid component is used as the resin for subbing. However, every light-sensitive photographic material prepared according to such subbing process is poor in the adhesive strength between the support and the photographic hydrolphilic layer under wet condition during development (such adhesive strength being referred to herein as wet film adhesion; the adhesion strength between support and photographic hydrophilic layer being referred to as film adhesion).In particular, in passing through an automatic developing machine, the light-sensitive photographic material prepared according to such subbing process has a tendency to cause "edge strip" when an edge of film runs against a part of the device during development, resulting in stripping of the photographic hyd rophilic layer at that portion. Thus, such subbing process is not one providing film adhesion as ordi narily usable. On the other hand, there has been proposed a subbing process using as the resin for subbing a copolymerwhich contains 10-90% by weight of a diolefin monomer as described in Japanese Patent Pre-Exam. Publication No. 50-43911, No. 51-121323, No.51-123139, No. 50-112326 or No.

51-58469,90-1 oO/o byweight of one or more of vinyl monomers and 30% by weight or less of an N-alkanolamido group-containing monomer, epoxy groups-containing monomer, hydroxyl groupcontaining monomer, ally group-containing monomer, acrylamide series monomer or aldehydo group-containing monomer as the cross-linking monomer. However, these subbing processes provide only unsatisfactory film adhesion to the gelatin-backing layer, though good adhesion is achieved thereby to the gelatin-silver halide emulsion layer.

On one hand, there has been known an example where increase in the film attachment is aimed at by using as the sub layer the diolefin compound as described in Japanese Patent Pre-Exam. Publication No. 49-11118 in combination with ethylene imine and/or methyl sulfone compound. However, in this case, the reactive additive remains still active even after completion of the subbing process and consequently as the polyester support on which the sub layer is applied is kept stored, the film adhesion to the photographic hydrophilic layer which should be applied thereon will be deteriorated.On the other hand, as an example for using a comparatively large amount of reactive component as the constituting element for the resin for subbing, there has been known such subbing process that uses a copolymer containing 20-60% or 20-90% by weight of the reactive component described in Japanese Patent Pre Exam. Publication No. 51-27918 or No. 52-104913, i.e. glycidyl methacrylate and/or glycidyl acrylate.

However, even when the above subbing process is carried out, there is required, depending upon the type of the photographic hydrophilic layers to be applied, use of a cross-linking additive, for example, 1 ,3-dimethylsulfoxypropane, in order to achieve good film adhesion, and in this case, deterioration of the subbed polyester support in the film adhesion with passage of time of storage cannot be avoided.

Accordingly, there is strong need for a polyester support with an improved sub layer.

An object of the present invention is to provide a polyester support which has such sub layer that gives good film adhesion to various photographic hydrophilic layers under various treatment conditions.

Another object is to provide a photographic polyester support having such sub layer which support may be recovered and re-used.

The other object is to provide a photographic polyester support which has such sub layer that does not emit any harmful gas at the burning treatment after the subbing process.

The other object is to provide a photographic polyester support which has such sub layer that need not use of any organic solvent or a swelling agent which becomes a cause of nuisance.

The other object is to provide a polyester support which has such sub layer that is free from deterioration with passage of time in film adhesion of subbed polyester support.

Further object is to provide a subbing process which is applicable even before monoaxial stretch ing effectively.

As a result of extensive researches, inventors of the present invention have succeeded to obtain the polyester support having a novel sub layer which achieves the afore-mentioned objects.

The above objects of the present invention can be achieved by such photographic polyester support that has on at least one surface thereof a layer which contains a copolymer comprising substantially a. 60-90% by weight of at least one monomer selected from glycidyl methacrylate and glycidyl acrylate (referred to as the first component), b. 10-40% by weight of at least one diolefin monomer (referred to as the second component) and c. 0-30 /O by weight of a vinyl monomer (referred to as the third component).

In the copolymer used for the sub layer according to the present invention, when the proportion in said copolymer of the first component, i.e. at least one monomer selected from glycidyl methacrylate and glycidyl acrylate exceeds 90% by weight, the adhesive power becomes so poor that there may be caused a problem in practical use. To the contrary, when the proportion of the first component is less than 60% by weight, wet film adhesion is unsatisfactory. In one of preferable embodiment of the present invention, the proportion of the first component is from 60 to 80 mole percents.

The term, diolefin monomer for the second component means a compound having two ethylene bondings in a molecule. Specifically, known conjugated and unconjugated dienes such as butadiene, isoprene, isobutene and 1,4-pentadiene are included. When the proportion of the above diolefin monomers in the copolymer according to this invention is more than 40% by weight, the blocking of the subbed polyester support during its transportation becomes worse and adhesion trouble may be caused between sub layers to each other after winding. When the proportion of the second component is less than 10% by weight, the sub layer cannot follow the stretch of the polyester support at the stretching stage in the film forming process of the polyester support and thus becomes readily breakable and will cause blushing in the finishing process, resulting in poor adhesion.The proportion of the sum of the first component and the second component in the copolymer may be any one so long as it is 70% by weight or more, though 80% by weight or more is more preferable.

As the third component, if necessary, 0-30% by weight of a vinyl monomer may be added. The vinyl monomer may be any one so far as it is copolymerizable with the first and the second components. Among vinyl monomers useful in the present invention are included vinyl esters such as vinyl acetate, vinyl butyrate and vinyl propionate; acrylic acid or methacrylic acid esters containing a hydroxyl group such as hydroxyethyl methacrylate, hydroxyethyl acrylate and hydroxypropyl methacrylate; acrylic acid or methacrylic acid esters of lower alcohols such as methyl acrylate, methyl methacry late and ethyl acrylate; acrylic acid or methacrylic acid amides such as acrylic amide, N-methyl acrylic amide, N-ethyl acrylic amide, N,N - di - dimethyl acrylic amide and vinyl ethers such as methyl vinyl ether and ethyl vinyl ether.In particular, copolymerization with a hydrophilic vinyl monomer as the third component enables such subbing process as causing no repelling, coating unevenness or drying unevenness with the use of a less amount of an active agent as compared with the case where a copolymer without such type of monomer is used.

Particularly preferable third component includes Vinyl acetate, hydroxyl group-containing vinyl monomer, acrylic amide and acrylic acid or methacrylic acid ester of an alcohol having 1 to 4 carbon atoms.

The copolymer according to this invention can be prepared by a known synthetic process similar to one for obtaining ordinary diolefin-containing latex.

In particular, emulsion polymerization in water dispersion system is preferable to the homogeneous polymerization in an organic solvent, which requires after treatment. For the polymerization, as the polymerization initiator, there can be used an organic or inorganic peroxide, peracetic acid, acetyl peroxide, benzoyl peroxide, lauryl peroxide, hydrogen peroxide and peracid salt such as percarbonate, persulfate and perborate. Further, in order to assist the ability of the above initiator, an organic or inorganic reducing agent as ordinarily employed may be used together. Furthermore, in order to increase the dispersion stability of latex during or after polymerization, various dispersion aids can be used.As the dispersion aid, there may be used high molecular protective colloid such as polyvinyl alcohol and hydroxymethyl cellulose and anionic or nonionic active agent such as sodium dodecylbenzenesulfonate, sodium laurate, polyoxyethylene fatty acid monoester and polyoxyethylene nonyl phenol ether. If necessary, mercaptans as the molecular weight regulator may be added. Polymerization is carried out in a closed container and the mode of addition of each component to the polymerization system, concentration of each component as well as temperature, pressure and agitation conditions during the polymerization reaction should be varied as required. The diolefin monomer may be added in excess amount to the calculated one which will be recovered after completion of the reaction.

Further, if necessary, a stabilizer for glycidyl group, reaction accelerator, cross-linking agent may be added either before of during the synthesis. After completion of the synthesis, a pH regulator, surface active agent, dispersion stabilizer, wetting agent, stabilizer for glycidyl group, particular stabilizer for other monomer, etc., should further be added to the resulting latex, according to an ordinary art to impart retention stability.

The following Examples will illustrate synthesis of the representative copolymers included within the copolymers used in the sub layer of the present invention and of comparative copolymer: Synthesis Example A Into an autoclave was charged 760cc or pure water and dry nitrogen was introduced with stirring at normal temperature for 30 minutes to deair. Then, the whole of the autoclave was cooled up to -20 C and 40cc of a 5% aqueous solution of sodium dodecyl sulfate and 0.5g of each of sodium hydrogen sulfite and ammonium persulfate were added.

Further, 409 of butadiene, 20g of vinyl acetate and 1409 of glycidel methacrylatewhich had been weighed separately were added and the autoclave was closed. Subsequently, the temperature was elevated with stirring and when the temperature amounted at 60 C, the temperature was kept at 60 C continuously. After the pressure get at 0, the reaction was continued for further one hour and thereafter cooling was effected. The time required for the completion of the reaction was 5 hours. The copolymer thus prepared was obtained as a composition in the form of an aqueous dispersion wherein said copolymer was dispersed in an aqueous dispersion medium as fine particles.

Synthesis Examples B to Q In an analogous process, copolymer compositions (latex) having different monomer composition were prepared as shown in Table 1.

Table 1 Synthesis Example Monomer Composition (O/o by weight} B Glycidyl methacrylate 90 Butadiene 10 C Glycidyl methacrylate 80 Butadiene 20 D Glycidyl methacrylate 70 Butadiene 30 E Glycidyl methacrylate 60 Butadiene 40 F Glycidyl methacrylate 50 Butadiene 50 G Glycidyl methacrylate 70 Isoprene 30 H Glycidyl acrylate 80 Butadiene 20 Glycidyl methacrylate 50 Glycidyl acrylate 20 Butadiene 30 J Glycidyl methacrylate 70 Butadiene 20 Isoprene 10 K Glycidyl methacrylate 70 Butadiene 25 Vinyl acetate 5 L Glycidyl methacrylate 70 Butadiene 15 Vinyl acetate 15 M Glycidyl methacrylate 70.

Butadiene 10 Vinyl acetate 20 N Glycidyl methacrylate 70 Butadiene 20 Hydroxyethyl methacrylate 10 O Glycidyl methacrylate 70 Butadiene 20 Acrylicamide. 10 P Itaconic acid 4 Butadiene 24 Styrene 72 Q Glycidyl methacrylate 3 Butadiene 40 Styrene 57 The aqueous dispersion solution which contains as the dispersion the copolymer according to the present invention obtained as above in an aqueous dispersion medium usually contains 3-40% by weight (preferably 4-300/a by weight) of the copolymer of the present invention and can be applied as the sub solution for the sub layer accord ing to the present invention. If necessary, an active agent, wetting agent, hydrophilic organic colloid, mat agent, lubricant antistatic agent or the like may further be added to the above aqueous dispersion solution.In particular, in order to inhibit the reaction of the epoxy group during the subbing process, a known alkali agent such as sodium hydroxide, sodium carbonate, potassium hydroxide, ammonium hydroxide, lithium hydroxide or a known cross-linking agent for epoxy resin such as pyromellitic acid, trimellitic acid or phenylenediamine is conveniently added. The type and quantity of these additives may vary depending upon the conditions for subbing process. Although neither wetting agent nor organic solvent for the polyester support need to be added to the sub solution containing the copolymer of the present invention, addition thereof within the extent where no adverse effect is caused thereby on the subbing ability is not obstructed.

The above sub solution can be applied on the polyester support before stretching or after monoaxial stretching, or biaxial stretching and heat set, without requiring any previous treatment being effected on the surface of said support, although to the polyester support which has been subjected to biaxial stretch and heat set, the sub solution is desirably applied after a known previous treatment such as corona discharge, flame treatment, plasma treatment or UV treatment has been effected.

The above sub solution can be coated on the polyester support in a manner known per so to the art, such as dip coating, double roll coating, curtain coating, reverse roll coating, fountain coating, slide hopper coating or spray coating. The amount of the copolymer applied at the time when the subbing process for the polyester support has been finished is 0.02-5g/m2 preferably 0.05-1 g/m2. When the amount is less than the above-mentioned range, the film adhesion is unsatisfactory and, to the contrary, when the amount exceeds the above range, cracking is readily caused during drying process after development treatment on the silver halide emulsion layer when it is applied.The drying process after coating of the sub solution can be carried out in a manner know per se to the art, such as hot-air drying, UV-heating drying, heater-roll drying or microwave drying.

At even stage being applied whether during or after completion of the film forming process of the polyester support, the sub layer according to this invention is able to provide strong adhesive power between the polyester support and the photographic hydrophilic layer. On such sub layer of the present invention, a second sub layer may further be applied, if necessary, after heat set. As the second sub layer, an aqueous solution of known natural hydrophilic organic colloid such as gelatin or casein, synthetic hydrophilic organic colloid or antistatic agent is particularly useful when it is coated and dried. In to the coating solution for this second sub layer, there may be included a mat agent, lubricant known cross-linking agent for epoxy resin or reaction inhibitor for epoxy resin, hardening agent, wetting agent, active agent or various antistatic regulating agents.There is no particular need to use the swelling agent and organic solvent for the polyester support, but use of them is not obstructed at all. For coating and drying the coating solution of the second sub layer, a known manner similar as that used for processing the sub layer according to the present invention can be used.

Either before or after the coating of the sub solution for the sub layer according to the present i nvention and the coating solution for the second sub layer which is applied, if necessary, a surface treatment known per se, such as corona discharge, flame treatment, plasma treatment or UV treatment may, if necessary, be effected.

The photographic polyester support to which the sub layer according to the present invention has been applied shows very strong adhesive power to a variety of photographic hydrophilic layers applied on the support throughout before and after the process of various photographic treatments as well as during said process. Further, such adhesive power does not suffer any loss due to lapse of time for storage of the polyester support to which the sub layer according to this invention has been applied.

What should be noted further is the fact that there has not been found heretofore any subbing polymer which is able to achieve the object of this invention among subbing polymers which can be used com money to each of the subbing processes as carried out before stretching or after monoaxial stretching and the subbing process as carried out after biaxial stretching and heat set, these subbing processes being quite different from each other in processes being quite different from each other in the functions thereof. Thus, according to the prior art, there was complexity that the mode of subbing process appropriate for each stage of process must be selected as to multiple equipments or subbing processes which are different from one another in the stage where they are to be applied. However, according to the sub layer of the present invention, almost the same process can be effected using the same polymer for subbing to achieve the object of this invention, irrespective of the stage where the subbing process is effected, namely even by any subbing process carried out at each stage before stretching, after monoaxial stretching or after biaxial stretching and heat set.

The present invention may be applied to any polyester film, which polyester is a linear polymer ester of a dihydric alcohol and dibasic organic acid.

The present invention will be illustrated further specifically in the following Examples.

Example 1 The copolymer composition (latex) as prepared according to the above Synthesis Example A was diluted with distilled water so that the concentration of the solid might be 10% by weight and the active agent of the formula

was added in the amount of 1% by weight of said copolymer.

Further, 0.1N aqueous sodium hydroxide solution was added to adjust pH value to 8.5. The sub solutiqn thus obtained was coated on a polyethylene terephthalate film support which has not been stretched at the thickness of 20 w and then dried at 90 C for 3 minutes. After stretching and heat set, the coating solution having the following composition used for a second sub layer was coated at the thickness of 20 it and then dried at 100 C for 2 minutes: Coating solution for second sub layer Gelatin 1g Saponin 0.029 Distilled water 1009 Subsequently, heat relaxation treatment was carried out at 1300C for 3 minutes.

In a similar manner as in the above process, subbing processes were carried out with the copolymer compositions prepared in the Synthesis Examples B to Q. On the subbed polyethylene terephthalate supports thus obtained, a silver halide emulsion layer for printing and gelatin backing layer were coated and dried according to an ordinary manner, respectively. With regard to samples of finished lightsensitive photographic materials, film adhesion under dry state before development treatment (referred to hereinafter as raw film attachment), wet film adhesion and film adhesion under dry state after development treatment (referred to hereinafter as dry film attachment) were evaluated according to the method as mentioned below to obtain results as shown in Table 2.

Evaluation Method of Film Adhesion (All of the evaluation methods in the following Examples are according to the similar method.) Raw film adhesion and Dry film adhesion: On the surface of the photographic hydrophilic layer of a sample which has been finished or dried subsequent to development treatment, a wound reaching up to the polyester support is inflicted in lattice form with an edge of razor at an angle of 450.

Over such wound adhesive tape (cellophan adhesive tape) is stuck under pressure and thereafter said tape is rapidly stripped off at an angle of about 450. The area of the photographic hydrophilic layer stripped off together with said tape is compared with the area where the tape was stuck and evaluated in terms of five grades.

Evaluation Grade /OStripping 5 quite no strip 4 0-20% 3 21 -50% 2 2 51-100% 1 more than 101% When an evaluation rate is 4 or higher, such film adhesion can be deemed as satisfactorily strong for practical use.

Wet film adhesion During various development treatments, a wound reaching up to the polyester support is inflicted with a sharp needle in lattice form on the surface of the photographic hydrophilic layer of a sample, and subsequently the surface of said layer is strongly rubbed for 10 seconds under still wet state. In this case, the surface of the photographic hydrophilic layer stripped off is compared with the lattice area and evaluated in terms of five grades. The base for this evaluation is the same as that used for the raw or dry film adhesion.

As apparent from Table 2, it is noted that the support to which the sub layer containing a copolymer according to the present invention has been applied before stretching is totally good in the film adhesion under various conditions to both silver halide emulsion layer and gelatin backing layer. To the contrary, the support to which the sub layer wherein the comparative copolymer (F, P or Q) is used has been applied is totally inferior to the sub layer of the present invention in the film adhesion.

Moreover, each of the samples obtained by the subbing process using the copolymers according to the present invention caused quite no edge stripping. Furthermore, even when the photographic hydrophilic layer of the same type as above was applied in a similar manner as above after lapse of storage time for 6 months of the subbed polyester support, a similar film adhesion result as that obtained before such lapse of storage time was shown.

Table 2 Silver halide emulsion Copolymer layer for printing Gelatin backing layer composition Raw Wet Dry Raw Wet Dry used for film film film film film film subbing adhe- adhe- adhe- adhe- adhe- adhe process sion sion sion sion sion sion A 5 5 5 5 5 5 B 4 5 4 3 5 3 C C 5 5 5 4 5 5 D 5 5 5 5 5 5 E 5 5 5 5 5 3 F 2 3 2 3 3 3 G 5 5 5 4 5 4 H 5 5 5 5 5 5 5 5 5 5 5 5 J 5 5 5 5 5 5 K 5 5 5 5 5 5 L 5 5 5 5 5 5 M 5 5 5 4 5 4 N 4 5 5 4 5 4 0 4 5 5 4 5 4 P 4 2 4 3 2 3 Q 4 2 4 3 2 3 Example 2 On the polyethylene terephthalate support stretched monoaxially in the longitudinal direction, a sub layer was applied in a manner similar to that in Example 1 and further a second sub layer was applied in a similar manner as in Example 1 after stretching in the transverse direction and heat set and then heat relaxation treatment was effected.On the subbed polyethylene terephthalate support thus obtained were coated a layer of a silver halide emulsion for printing and gelatin backing layer in an ordinary manner and then dried. With regard to samples of the finished, light-sensitive photographic materials, raw, wet and dry film adhesion were evaluated.

Results obtained are shown in Table 3.

Table 3 Silver halide emulsion Copolymer layer for printing Gelatin backing layer composition Raw Wet Dry Raw Wet Dry used for film film film film film film subbing adhe- adhe- adhe- adhe- adhe- adhe process sion sion sion sion sion sion A 5 5 5 5 5 5 C 4 5 5 4 5 4 F 4 4 4 3 4 3 M 4 5 5 4 5 4 N 4 5 5 4 5 4 0 4 5 5 4 5 4 As apparent from Table 3, it is noted that the supports having the sub layers according to the present invention show good film adhesion under various conditions to both the silver halide emulsion layer and gelatin backing layer even when the subbing process is carried out after monoaxial stretching but before biaxial stretching. To the contrary, the support having the sub layer obtained from the comparative copolymer (F) is poor in the film adhesion to the gelatin backing layer.

Further, edge stripping was caused in the case where the copolymer F was used, whereas no edge stripping was caused in other cases. Moreover, a similar test carried out on a sample prepared by coating the photographic hydrophilic layer on the same subbed support as above but after its storage for 6 months gave quite the same results as those shown in Table 3.

Example 3 In a similar manner as in Example 1, the sub layer and the second sub layer were applied on the surface of stretched and heat set polyethylene terephthalate support, immediately after corona diseharge treatment of 50Wlm2lmin applied to said surface. On the support thus subbed were coated a layer of a silver halide emulsion for use in printing and gelatin backing layer in an ordinary manner and then dried.

With regard to the finished, light-sensitive photographic material, raw wet and dry film adhesions were evaluated. Results of this evaluation are shown in Table 4.

Table 4 Silver halide emulsion Copolymer layerforprinting Gelatin backing layer composition Raw Wet Dry Raw Wet Dry used for film film film film film film subbing adhe- adhe- adhe- adhe- adhe- adhe process sion sion sion sion sion sion A 5 5 5 4 5 4 C 5 5 5 4 5 4 F 5 5 5 5 4 3 M 5 5 5 4 5 4 N 5 5 5 4 5 4 O 5 5 5 4 5 4 P 5 3 5 3 2 3 Q 5 3 5 3 2 3 As apparent from Table 4, the sub layers according to the present invention are totally superior in the film adhesion to the comparative sub layers (F, P and Q), even when corona discharge treatment was applied to the stretched and heat set polyethylene terephthalate support.

Further, the edge stripping was caused in the cases where the copolymers F, P and 0 were used, respectively, whereas no edge stripping was caused in other cases. Moreover, a similar test carried out on a sample prepared by coating the photographic hydrophilic layer on the same subbed polyester support as above but after its storage for 6 months gave the same results as those shown in Table 4.

Example 4 In a similar manner as in Example 1 excepting that coating of the second sub layer was omitted, samples wherein a layer of a silver halide emulsion for use in printing and a layer of a silver halide emulsion for use in roentgenogram were applied, respectively, were prepared and film adhesions were evaluated. Results obtained are shown in Table 5.

Table 5 Silver halide emulsion Silver halide emulsion layer for printing layer for roentgenogram Copolymer Raw Wet Dry Raw Wet Dry composition film film film film film film subbing adhe- adhe- adhe- adhe- adhe- adhe process sion sion sion sion sion sion A 5 5 5 4 5 5 D 5 5 5 4 5 5 N 4 5 4 4 5 5 0 4 5 4 -- 4 5 5 As apparent from Table 5, various film adhesions were good even when the sub layers according to the present invention were applied to the polyethylene terephthalate support before stretching without effecting any pre-treatment on the surface, such as corona discharge treatment and the photographic hydrophilic layer was directly applied without coating any second sub layer.

Further, no edge stripping was caused in each case and the same evaluation results were obtained in test carried out on samples prepared by coating the silver halide emulsion layer in a similar manner as above after storage of the above subbed support for 6 months.

Claims (11)

1. A polyester support for use in photography, which comprises on at least one surface thereof a layer containing a copolymerwhich comprises a) 60 to 90 /O by weight of at least one monomer selected from glycidyl methacrylate and glycidyl acrylate (first component), b) 10 to 40% by weight of at least one diolefin monomer (second component), and c) 0 to 30% by weight of a vinyl monomer (third component).

2. A polyester support according to Claim 1, wherein the copolymer comprises 60 to 80% by weight of the first component

3. A polyester support according to Claim 1 or 2 wherein the sum of the first component and the second component of the copolymer is at least 80% by weight.

4. A polyester support according to any preceding Claim wherein the vinyl monomer is a hydrophilic vinyl monomer.

5. A polyester support according to Claim 4 wherein the hydrophilic monomer is vinyl acetate, a hydroxyl group-containing vinyl monomer, acrylic amide or an ester of an alcohol containing 1 to 4 carbon atoms with acrylic acid or methacrylic acid.

6. A polyester support according to any preceding Claim which comprises the copolymer layer in an amount from 0.02 to 5 g/m2.

7. A polyester support according to Claim 6 wherein the amount of copolymer layer is from 0.05 to 1 glum2.

8. A polyester support according to any preceding Claim wherein the copolymer layer is applied before stretching.

9. A polyester support according to any of Claims 1 1 to 7 wherein the copolymer layer is applied after monoaxial or biaxial stretching.

10. A polyester support according to Claim 1 and substantially as hereinbefore described with referonce to any of Examples 1 to 4.

11. A photographic film which comprises a photosensitive emulsion and a support according to any of the preceding Claims.