JPH06180481A - Photographic support - Google Patents

Abstract

PURPOSE:To enhance mechanical strength as well as resistance to winding tendency caused by development processing, and to prevent deterioration of planeness even in heat treatment at high temperature by using a specified copolymerized polyester film made partly from a small amount of diethylene glycol. CONSTITUTION:The support is formed with a film made of the copolymerized polyester having an aromatic dicarboxylic acid having a metal sulfonate group as a monomer unit and containing the diethylene glycol in an amount of <=5mol% of the total ester bonds. This copolymerized polyester may have polyalkylene glycols and/or 4-20C aliphatic dicarboxylic acids as the copolymer component, so long as it has the aromatic dicarboxylic acid having a metal sulfonate group and the diethylene glycol as the copolymer components, and it can be embodied as a preferable example by the copolymerized polyester obtained by using the aromatic dicarboxylic acid having a metal sulfonate group and a small amount of diethylene glycol as the copolymer components and an aromatic dicarboxylic acid and ethylene glycol as the main copolymer components.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to a photographic support,
More specifically, it relates to a photographic support suitable for a silver halide photographic light-sensitive material, which is capable of easily eliminating curl after development, while maintaining its strength. Also,
The present invention relates to a photographic support suitable as a photographic film (sometimes referred to as a photographic light-sensitive material) that can be loaded in a small camera.

[0002]

2. Description of the Related Art In recent years, with the downsizing of photographing devices such as cameras, various technical problems have arisen for photographic light-sensitive materials.

For example, in order to achieve downsizing of a photographing device, it is necessary to make the photographic support thin. However, when the photographic support is made thin, the so-called stiffness becomes weak, so that the transportability of the photographic film in the photographing device or the handleability in the development processing step in the development processing machine deteriorates. In order to solve such a problem, the mechanical strength, especially the elastic modulus, of the photographic support must be made larger than that conventionally used.

By the way, as a plastic used for a conventional photographic support, triacetyl cellulose (T
AC) and polyethylene terephthalate (PET) are typical.

The TAC film has a property that it has no optical anisotropy and high transparency.
The photographic light-sensitive material using the C film as a photographic support has an excellent property that the curl can be swiftly taken after development processing. However, the TAC film has a drawback that mechanical strength is originally low.

On the other hand, the PET film has excellent productivity, mechanical strength, dimensional stability and the like, and is therefore mainly used for sheet films such as X-ray films. However, the roll form widely used as a photographic light-sensitive material has a drawback that it is difficult to take a curl after the above-mentioned development processing. Therefore,
The use of PET film is considerably limited in the field of photosensitive materials.

If the curling tendency is strong, problems such as poor conveyance in various automatic conveying devices, scratches on the negative photosensitive material, and defocusing at the time of print printing may occur.

In order to improve the characteristic of eliminating the curl, that is, the curl recovery property, the PET film was imparted with hydrophilicity by using an aromatic dicarboxylic acid having a metal sulfonate group as a copolymer component. It has been proposed to use a copolyester (see JP-A-1-244446). However, with this method, it is possible to obtain good curl recovery,
The heat treatment causes a new problem that the flatness is deteriorated.

Generally, a photographic light-sensitive material is produced by coating a film such as PET or TAC with a functional layer such as an adhesive layer, an antistatic layer or a slippery layer, and further coating a photographic light-sensitive layer. From the viewpoint of safety and environment, the mainstream application of such a functional layer is to apply an aqueous functional layer coating liquid.

In general, in comparison with a solvent-based functional layer coating liquid, a water-based functional layer coating liquid requires heat treatment at a high temperature in order to dry the coating liquid. Moreover, to improve productivity,
Heat treatments at higher temperatures tend to be performed. Therefore, the photographic support itself is required to have sufficient heat resistance to withstand such a high temperature.

Further, since deterioration of the flatness of the photographic support causes various coating failures in the subsequent steps, it is important that the photographic support does not deteriorate in flatness even by heat treatment at high temperature. It is a characteristic.

An object of the present invention is to solve the above problems,
An object of the present invention is to provide a photographic support which has excellent mechanical strength and also has a curl recovery property after development, and whose flatness is not deteriorated even by heat treatment at high temperature.

[0013]

The invention according to claim 1 for achieving the above object is a film made of a copolyester having an aromatic dicarboxylic acid having a metal sulfonate group as a monomer unit. ,
The film according to claim 2, wherein the content of diethylene glycol in the film is 5 mol% or less based on all ester bonds, and the copolymerized polyester is used as a monomer unit. The photographic support according to claim 1 containing a polyalkylene glycol, and the invention according to claim 3 is characterized in that the copolymerized polyester further comprises an aliphatic dicarboxylic acid having 4 to 20 carbon atoms as a monomer unit. The photographic support according to claim 1 or 2, wherein the copolyester is sodium acetate, sodium hydroxide, tetraethyl at the time of transesterification and / or polymerization. The said 1-3 obtained by adding at least 1 sort (s) selected from the group which consists of hydroxyammonium. It is a photographic support according to any one.

The present invention will be described in detail below.

As the copolyester in the present invention, a copolyester having an aromatic dicarboxylic acid having a metal sulfonate group and a small amount of diethylene glycol as a copolymer component and an aromatic dibasic acid and a glycol as main constituents is preferable. As an example:

Examples of the aromatic dibasic acid include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, and the glycols are ethylene glycol, propylene glycol, butanediol,
Examples include neopentyl glycol, 1,4-cyclohexanedimethanol, p-xylylene glycol and the like. Among these, terephthalic acid is preferable as the aromatic dibasic acid, and ethylene glycol is preferable as the glycol.

Examples of the aromatic dicarboxylic acid having a metal sulfonate group include 5-sodium sulfoisophthalic acid, 2-sodium sulfoisophthalic acid, 4-sodium sulfoisophthalic acid, 4-sodium sulfo-2,6.
-Naphthalenedicarboxylic acid, or an ester-forming derivative represented by the following (Chemical formula 1), and compounds obtained by substituting these sodiums with other metals such as potassium and lithium can be given.

[0018]

[Chemical 1]

In the copolymerized polyester having an aromatic dicarboxylic acid having a metal sulfonate group as a monomer unit in the present invention, the amount of the aromatic dicarboxylic acid having a metal sulfonate group, which can be detected by hydrolyzing the same, is , 2 to 7 mol% based on all ester bond units. If the amount of the aromatic dicarboxylic acid having a metal sulfonate group is less than 2 mol%, the curl of the photographic film may not be sufficiently recovered, and if it exceeds 7 mol%, the heat resistance of the photographic support is poor. May be.

The copolymerized polyester in the present invention is
It contains diethylene glycol in a proportion of 5 mol% or less based on all ester bonds. The amount of this diethylene glycol is a value detected by hydrolyzing the copolyester. By containing this diethylene glycol in a proportion of 5 mol% or less with respect to all ester bonds, the photographic support of the present invention is excellent in curl recovery, and moreover, various aqueous systems are formed on the surface of the photographic support. Even if a coating solution is applied and heat-treated at a high temperature, the flatness of the photographic support can be prevented from decreasing.

The copolymerized polyester in the present invention is
As long as it has an aromatic dicarboxylic acid having a metal sulfonate group as a monomer unit and diethylene glycol, and does not impair the object of the present invention, polyalkylene glycols and / or C 4 -C 2
The aliphatic dicarboxylic acid of 0 may be contained as a copolymerization component.

Examples of the polyalkylene glycols include polyethylene glycol, polypropylene glycol, polytetramethylene glycol and the like and derivatives thereof. The molecular weight of the polyalkylene glycol that can be used is not particularly limited, but is preferably 300 to 20,000, more preferably 600 to 10,000, and particularly preferably 1.00.
It is 0 to 5,000. As the polyalkylene glycol, polyalkylene glycol is particularly preferable, and among them, polyethylene glycol represented by the formula (a) is particularly preferable. H (O—CH ₂ CH ₂ ) _n —OH (a) As the polyalkylene glycol, the polyethyleneoxydicarboxylic acid represented by the formula (b) in which the terminal —H of polyethylene glycol is replaced with —CH ₂ COOR (R: H or an alkyl group having 1 to 10 carbon atoms, n:
A positive integer), a polyether dicarboxylic acid represented by the formula (c) (R ': H or an alkylene group having 2 to 10 carbon atoms, n: a positive integer) and the like can be used to obtain the same effect.

ROOCCH _2- (O-CH ₂ CH ₂ ) _n -OCH ₂ COOR (b) ROOCCH _2- (O-R ') _n -OCH ₂ COOR (C) (b) A compound represented by the formula and ( There is no particular limitation on the molecular weight of any of the compounds represented by the formula c).
0 to 20,000 is preferable, more preferably 600 to
It is 10,000, and particularly preferably 1,000 to 5,000.

The amount of polyalkylene glycol added is usually 3 to 10% based on the total weight of the reaction product.

Examples of the aliphatic dicarboxylic acid having 4 to 20 carbon atoms include succinic acid, adipic acid, sebacic acid, etc. Of these, adipic acid is preferred.

When the copolymerized polyester having an aromatic dicarboxylic acid having a metal sulfonate group as a monomer unit and diethylene glycol in the present invention contains an aliphatic dicarboxylic acid as a monomer unit, the copolymerized polyester is hydrolyzed. The amount of aliphatic dicarboxylic acid thus detected is usually 3 to 25 mol% based on all ester bonds. When the aliphatic dicarboxylic acid as a monomer unit is contained in the copolyester so that the amount of the aliphatic dicarboxylic acid is within the above range, the curl of the photographic film can be easily eliminated, and the photographic film can be easily removed. The support for use can be provided with practical heat resistance.

The copolyester used in the present invention may have other types of monomer units as long as the object of the present invention is not impaired.

The copolyester having an aromatic dicarboxylic acid having a metal sulfonate group as a monomer unit is not particularly limited in its production method. For example, after transesterifying the dicarboxylic acid component and the glycol component, a high temperature is used. And polycondensation under reduced pressure. At this time, the copolymerization component,
For example, aromatic dicarboxylic acids containing a metal sulfonate group or polyethylene glycols may be added during the transesterification reaction, or may be polycondensed after the transesterification reaction.

Examples of the catalyst used for this transesterification include acetates, fatty acid salts, carbonates and the like of metals such as manganese, calcium, zinc and cobalt. Of these, hydrates of manganese acetate and calcium acetate are preferable, and it is preferable to use them in combination.

It is also effective to add a hydroxide, a metal salt of an aliphatic carboxylic acid, a quaternary ammonium or the like to the extent that the reaction is not inhibited or the polymer is colored during the transesterification and / or polycondensation. Among them, sodium hydroxide, sodium acetate and tetraethylhydroxyammonium are preferable, and sodium acetate is particularly preferable. The addition amount of these is 1 × 10 ^-2 to 2 with respect to all acid components.
0 × 10 ^-2 mol% is preferable.

The copolyester used in the present invention is phosphoric acid, phosphorous acid,
And their esters and inorganic particles (for example, silica, kaolin, calcium carbonate, calcium phosphate, titanium dioxide, etc.), or the inorganic particles appropriately added after the polymerization.

The copolymerized polyester may contain a dye, an ultraviolet absorber, an antioxidant, etc., which are appropriately added during the transesterification reaction, at any of the polymerization stage and the post-polymerization stage. .

The photographic support of the present invention preferably contains a specific copolyester and an antioxidant.

The type of the antioxidant is not particularly limited, and specific examples thereof include hindered phenol compounds, allylamine compounds, phosphite compounds and thioether antioxidants. . Among these, hindered phenol compounds are preferable. Among them, the compounds represented by the compound numbers 1 and 2 in (Chemical Formula 2) are preferable.

The content of the antioxidant in the photographic support is usually 0.01 to the copolymerized polyester in order not to increase the turbidity of the copolymerized polyester and to obtain an excellent photographic performance effect. 2% by weight, preferably 0.1
It is 0.5% by weight. In addition, these antioxidants can be used alone or in combination of two or more thereof.

Next, the structural formula of the antioxidant that can be used in the present invention is shown.

[0037]

[Chemical 2]

[0038]

[Chemical 3]

[0039]

[Chemical 4]

[0040]

[Chemical 5]

[0041]

[Chemical 6]

[0042]

[Chemical 7]

[0043]

[Chemical 8]

[0044]

[Chemical 9]

[0045]

[Chemical 10]

[0046]

[Chemical 11]

[0047]

[Chemical 12]

[0048]

[Chemical 13]

[0049]

[Chemical 14]

Further, the photographic support according to the present invention has a light piping phenomenon (fogging) which occurs when light is incident on the photographic support coated with a photographic emulsion layer from an edge.
For the purpose of preventing this, it is preferable to incorporate a dye in this photographic support. The dye to be blended for such a purpose is not particularly limited in its type, but in the film forming process of the film, a dye excellent in heat resistance is preferable,
For example, anthraquinone type chemical dye and the like can be mentioned. Further, as the color tone of the photographic support, gray dyeing is preferable as seen in general light-sensitive materials, and one kind or two or more kinds of dyes can be mixed and used. As these dyes, S manufactured by Sumitomo Chemical Co., Ltd.
UMIPLAST, Mitsubishi Kasei Kogyo's Diar
Dyes such as MACREX manufactured by Esin and Bayer can be used alone or in an appropriate mixture.

The photographic support of the present invention comprises, for example, the above-mentioned copolyester, or an antioxidant optionally blended with the copolyester, or a group consisting of sodium acetate, sodium hydroxide and tetraethylhydroxyammonium. After sufficiently drying the copolyester composition containing at least one selected, the composition is melt extruded into a sheet through an extruder, a filter, a die and the like controlled in a temperature range of 260 to 320 ° C., and the molten polymer is rotated. It is cooled and solidified on a cooling drum to obtain an unstretched film. After that, the unstretched film can be produced by biaxially stretching in the machine direction and the transverse direction and heat-setting.

The stretching conditions of the film vary depending on the copolymerization composition of the copolyester, and therefore cannot be uniformly defined. However, the stretching ratio in the temperature range from the glass transition temperature (Tg) of the copolyester to Tg + 100 ° C. in the longitudinal direction. 2.5-6.0 times, Tg + 5 ° C to Tg + 50 in the lateral direction
The draw ratio is in the range of 2.5 to 4.0 times in the temperature range of ° C. The biaxially stretched film obtained as described above is usually heat set and cooled at 150 ° C to 240 ° C. In this case, if necessary, it may be relaxed in the vertical direction and / or the horizontal direction.

The photographic support of the present invention may be a single-layer film or sheet formed by the above-mentioned method, or may be a film or sheet of another material formed by a coextrusion method or a laminating method. It may have a multilayer structure in which a film or sheet formed by the above method is laminated.

The thickness of the photographic support of the present invention thus obtained is not particularly limited, but is 40 to 20.
0 μm, particularly 50 to 100 μm is preferable. The photographic support of the present invention can achieve the object of the present invention well even if it has such a small thickness.

The photographic support of the present invention is particularly suitable as a photographic film support used in the form of a roll.

The photographic film has the following layer structure using the photographic support of the present invention.

That is, the photographic film has at least one silver halide emulsion layer on at least one surface of the photographic support of the present invention. In other words, this silver halide emulsion layer may be provided on at least one layer on one side of the photographic support, or may be provided on at least one layer on both sides of the photographic support. The silver halide emulsion can be coated directly on the photographic support or can be coated through another layer, for example, a hydrophilic colloid layer containing no silver halide emulsion, and A hydrophilic colloid layer as a protective layer may be coated on the silver halide emulsion layer. Further, the silver halide emulsion layers may be separately coated on each of the silver halide emulsion layers having different sensitivities, for example, high sensitivity and low sensitivity. In this case, an intermediate layer may be provided between each silver halide emulsion layer. That is, you may provide the intermediate layer which consists of hydrophilic colloids as needed. Further, a non-photosensitive hydrophilic colloid layer such as an intermediate layer, a protective layer, an antihalation layer and a backing layer may be provided between the silver halide emulsion layer and the protective layer.

The silver halide used in the silver halide emulsion may have any composition.
Examples thereof include silver chloride, silver chlorobromide, silver chloroiodobromide, pure silver bromide and silver iodobromide.

Further, this silver halide emulsion may contain a sensitizing dye, a plasticizer, an antistatic agent, a surfactant, a hardener and the like.

To develop a photographic film using the photographic support of the present invention, for example, T.W. H. James, The Theory of The Photografic Process,
Forth Edition) pp. 291-334 and Journal of the American Chemical Society 7th
The developer described in Volume 3, page 3,100 (1951) can be used.

[0061]

【Example】

(Example 1) To 100 parts by weight of dimethyl terephthalate and 64 parts by weight of ethylene glycol, 0.1 part by weight of calcium acetate hydrate as an ester exchange catalyst was added, and an ester exchange reaction was carried out according to a conventional method.

28 parts by weight of an ethylene glycol solution of 5-sodium sulfodi (β-hydroxyethyl) isophthalic acid (concentration: 35% by weight), and 8 parts by weight of polyethylene glycol (number average molecular weight: 3000) were added to the obtained product. , 0.05 parts by weight of antimony trioxide, 0.13 parts by weight of phosphoric acid trimethyl ester, and 0.02 parts by weight of sodium hydroxide were added. Then, the temperature was gradually raised and the pressure was reduced, and polymerization was carried out at 280 ° C. and 0.5 mmHg to obtain a copolyester. The copolymer contained diethylene glycol, which is a by-product of the polymerization reaction, as an acid component.

The copolyester was vacuum dried at 150 ° C., melt-extruded at 280 ° C., and rapidly cooled and solidified on a cooling drum to prepare an unstretched film. This unstretched film was stretched 3.3 times in the vertical direction at 80 ° C., then 3.3 times in the horizontal direction at 90 ° C., and then 220 ° C.
Was heat set for 30 seconds to obtain a biaxially stretched film having a thickness of 80 μm. The diethylene glycol content of this biaxially stretched film was determined according to the following formulation, and its flatness and curl recovery property were evaluated by the following evaluation methods. The results are shown in Table 1. Although this film is slightly colored in appearance, such coloring is not a problem in practical use, and as is clear from Table 1, the content of diethylene glycol is 4 mol% and the flatness and curl The recoverability was good.

<Diethylene glycol content> 2 g of the crushed film was added to 50 ml of a 1N potassium hydroxide methanol solution, and the mixture was heated and dissolved under reflux for 90 minutes while stirring. Then, 10 ml of pure water was added, and heating was continued for another 30 minutes. Then terephthalic acid 7
g, and the mixture was further heated and stirred for 20 minutes, cooled to room temperature, 5 ml of a 1 vol% methanol solution of tetraethylene glycol dimethyl ether was added, and the mixture was stirred for 5 minutes. The liquid thus obtained was filtered, the filtrate was analyzed by gas chromatography, and the diethylene glycol content was determined by a calibration curve determined in advance.

<Flatness> The film was conditioned at 23 ° C. and 55% relative humidity for 4 hours or more, and then cut into 120 mm × 150 mm, and the film was cut in a hot air oven at 150 ° C. for 30 minutes without tension. Heat treated. After conditioning the heat-treated film at 23 ° C. to a relative humidity of 55%, the degree of waviness was visually evaluated and ranked according to the following criteria. The practicality in this ranking is determined based on the acceptability as a photographic support, and if it is rank 3 or higher, there is no practical problem.

(Rank and its contents) 5 ... Extremely good, 4 ... Good, 3 ... Ripples can be seen by looking closely, 2 ... Ripples are moderate, 1 ... Ripples Very big.

<Curling tendency recovery property> A 12 cm x 35 mm film was wound around a winding core having a diameter of 10 mm and left standing for 3 days at 55 ° C and 20% RH to give a winding tendency. Thereafter, the film was released from the winding core. Put the film in pure water at 38 ℃ 1
It was immersed for 5 minutes. Thereafter, a load of 50 g was applied to the film, and the film was dried in a hot air dryer at 55 ° C. for 3 minutes. The load was released from the film after 3 minutes and the film was hung vertically. The distance between the ends of the hung film was determined. Then, it was evaluated how much the curl was recovered with respect to the original length of 12 cm. Practically 50% or more, particularly 80% or more is preferable as a photographic support, and there is no problem as a photographic film.

Example 2 A biaxially stretched film having a thickness of 80 μm was prepared in the same manner as in Example 1 except that 0.07 parts by weight of tetraethylhydroxyammonium was added instead of sodium hydroxide in Example 1. Got
This film was evaluated in the same manner as in Example 1 above,
The results are shown in Table 1. As in Example 1 above, this film was slightly colored in appearance but was not a problem in practical use, and as is clear from Table 1, the content of diethylene glycol was 5 mol%, There was no practical problem in both sex and curl recovery.

Example 3 A biaxial tube having a thickness of 80 μm was prepared in the same manner as in Example 1 except that 0.04% by weight of sodium acetate was added during the transesterification reaction instead of sodium hydroxide in Example 1. A stretched film was obtained.
The obtained film was evaluated in the same manner as in Example 1, and the results are shown in Table 1. As in Example 1, the film was slightly colored in appearance but was not a problem in practical use, and as is clear from Table 1, the content of diethylene glycol was 3 mol%.
There were practically no problems in flatness and curl recovery.

Further, a photographic film provided with a photographic photosensitive layer on this film by a known method had practically no problem and had good performance.

(Example 4) Dimethyl terephthalate 100
To 0.1 part by weight of ethylene glycol, 70 parts by weight of ethylene glycol, and 10 parts by weight of dimethyl adipate, 0.1 part by weight of calcium acetate hydrate was added as a transesterification catalyst, and transesterification reaction was carried out according to a conventional method.

32 parts by weight of an ethylene glycol solution of 5-sodium sulfodi (β-hydroxyethyl) isophthalic acid (concentration 35% by weight), antimony trioxide 0.05 part by weight, phosphoric acid trimethyl ester were added to the obtained product. 0.13 parts by weight and 0.04 parts by weight of sodium acetate were added. Then, gradually raise the temperature and reduce the pressure to 280
Polymerization was performed at 0.5 ° C. and 0.5 mmHg to obtain a copolyester.

The copolyester was vacuum dried at 150 ° C., melt-extruded at 280 ° C. and rapidly cooled and solidified on a cooling drum to prepare an unstretched film. This unstretched film was stretched 3.3 times in the vertical direction at 80 ° C., then 3.3 times in the horizontal direction at 90 ° C., and then 200 ° C.
Was heat set for 30 seconds to obtain a biaxially stretched film having a thickness of 80 μm. For this biaxially stretched film, the content of diethylene glycol was determined in the same manner as in Example 1 above, and the flatness and curl recovery property thereof were evaluated by the same evaluation method as in Example 1. The results are shown in Table 1.
It was shown to. This film is colorless and transparent in its appearance,
As is clear from Table 1, the diethylene glycol content was 3 mol%, and the flatness and the curl recovery property were good.

Example 5 Dimethyl terephthalate 100
Parts by weight, ethylene glycol 64 parts by weight, dimethyl 5-sodium sulfoisophthalate 10 parts by weight, polyethylene glycol (number average molecular weight: 1,000) 8 parts by weight,
Calcium acetate 0.1 part by weight, sodium acetate 0.04
By weight, antimony trioxide (0.05 parts by weight) and Irganox 1010 (manufactured by CIBA-GEIGY) (0.5 parts by weight) were added, and a transesterification reaction was carried out by a conventional method. 0.1 parts by weight of phosphoric acid trimethyl ester was added to the obtained product, the temperature was gradually raised and the pressure was reduced, and finally 280 ° C.
Polymerization was performed at 0.5 mmHg to obtain a copolyester having an intrinsic viscosity of 0.50.

The copolyester was vacuum dried at 150 ° C., melt-extruded at 280 ° C. and rapidly solidified on a cooling drum to prepare an unstretched sheet. This unstretched sheet was stretched 3.3 times in the vertical direction at 80 ° C.
After stretching 3.3 times in the horizontal direction at 0 ° C, 30 times at 180 ° C
It was heat set for 2 seconds to obtain a biaxially stretched film having a thickness of 100 μm. The biaxially stretched film was evaluated in the same manner as in Example 1, and the results are shown in Table 1. This film is colored yellow in appearance and is inferior in quality as a photographic support as compared with the films in the other Examples, but is in a practically usable range, and as shown in Table 1, it contains diethylene glycol. The amount was 5 mol%, and the flatness and the curl recovery property were good.

Comparative Example 1 Dimethyl terephthalate 100
0.1 part by weight of calcium acetate hydrate as an ester exchange catalyst was added to 64 parts by weight of ethylene glycol and 64 parts by weight of ethylene glycol, and transesterification reaction was carried out according to a conventional method.

28 parts by weight of an ethylene glycol solution of 5-sodium sulfodi (β-hydroxyethyl) isophthalic acid (concentration: 35% by weight) and 8 parts by weight of polyethylene glycol (number average molecular weight: 3,000) were added to the obtained product. ,
0.05 parts by weight of antimony trioxide and 0.13 parts by weight of phosphoric acid trimethyl ester were added. Then, the temperature was gradually raised and the pressure was reduced, and polymerization was carried out at 280 ° C. and 0.5 mmHg to obtain a copolyester.

The copolyester was vacuum dried at 150 ° C., melt-extruded at 280 ° C. and rapidly cooled and solidified on a cooling drum to prepare an unstretched film. This unstretched film was stretched 3.3 times in the vertical direction at 80 ° C., then 3.3 times in the horizontal direction at 90 ° C., and then 200 ° C.
Was heat set for 30 seconds to obtain a biaxially stretched film having a thickness of 80 μm. For this biaxially stretched film, the content of diethylene glycol was determined in the same manner as in Example 1 above, and the flatness and curl recovery property thereof were evaluated by the same evaluation method as in Example 1. The results are shown in Table 1.
It was shown to. Although this film does not cause any particular problem in terms of its appearance, as is clear from Table 1, the diethylene glycol content was 8 mol% and the film was inferior in flatness.

(Comparative Example 2) A biaxially stretched film was obtained in the same manner as in Comparative Example 1 except that the heat setting temperature in Comparative Example 1 was changed to 220 ° C. This film was slightly cloudy in appearance and was inferior in transparency, and as shown in Table 1, it was inferior in flatness. (Comparative Example 3) 100 parts by weight of dimethyl terephthalate, 70 parts by weight of ethylene glycol, and dimethyl adipate 1
To 0 part by weight, 0.1 part by weight of calcium acetate hydrate as a transesterification catalyst was added, and the transesterification reaction was carried out according to a conventional method.

The obtained product was mixed with 32 parts by weight of a solution of 5-sodium sulfodi (β-hydroxyethyl) isophthalic acid in ethylene glycol (concentration: 35% by weight), 0.05 parts by weight of antimony trioxide, and trimethyl phosphate. 0.13 parts by weight of ester was added. Then gradually raise the temperature,
The pressure was reduced and polymerization was carried out at 280 ° C. and 0.5 mmHg to obtain a copolyester.

This copolymerized polyester was vacuum dried at 150 ° C., melt-extruded at 280 ° C., and rapidly solidified on a cooling drum to prepare an unstretched film. This unstretched film was stretched 3.3 times in the vertical direction at 80 ° C., then 3.3 times in the horizontal direction at 90 ° C., and then 180 ° C.
Was heat set for 30 seconds to obtain a biaxially stretched film having a thickness of 80 μm. For this biaxially stretched film, the content of diethylene glycol was determined in the same manner as in Example 1 above, and the flatness and curl recovery property thereof were evaluated by the same evaluation method as in Example 1. The results are shown in Table 1.
It was shown to. This film was colorless and transparent in appearance, but as apparent from Table 1, the diethylene glycol content was 9 mol%, and the flatness was poor.

(Comparative Example 4) A biaxially stretched film was obtained in the same manner as in Comparative Example 3 except that the heat setting temperature in Comparative Example 3 was changed to 220 ° C. This film was partially cloudy in appearance and could not be put to practical use.

Example 6 Dimethyl terephthalate 100
Parts by weight, 70 parts by weight of ethylene glycol, 10 parts by weight of dimethyl 5-sodium sulfoisophthalate, polyethyleneoxydicarboxylic acid (number average molecular weight: 3,000) 1
0 part by weight, antimony trioxide 0.05 part by weight, phosphoric acid trimethyl ester 0.13 part by weight and sodium acetate 0.05 part by weight were charged in the reaction vessel. Then, the reaction system is gradually heated and depressurized at 280 ° C. and 0.5 mmH.
Polymerization was performed with g to obtain a copolyester. Using the obtained copolyester, a biaxially stretched film having a thickness of 80 μm was obtained in the same manner as in Example 1. This film was evaluated by the same evaluation method as in Example 1, and the results are shown in Table 1. The film was colored a little yellow in appearance, but there was no problem in practical use. As shown in Table 1, the content of diethylene glycol was 5 mol%, and there were no problems in practical use in terms of flatness and curl recovery.

[0084]

[Table 1]

[0085]

According to the present invention, while maintaining strength,
It is possible to provide a photographic support having excellent curl recovery after development processing.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kenji Nakanishi 1st Sakura-cho, Hino-shi, Tokyo Konica Co., Ltd. (72) Inventor Yoshioki Okubo 2-33-5 Soja-sha, Hofu-shi, Yamaguchi (72) Inventor Hashimura Tetsutaro 1751-15 Nitta, Hofu City, Yamaguchi Prefecture (72) Inventor Hiroshi Naito 2265-5 Yoshikashi, Yamaguchi City, Yamaguchi Prefecture

Claims (4)

[Claims] 1. A film made of a copolyester having an aromatic dicarboxylic acid having a metal sulfonate group as a monomer unit, wherein the content of diethylene glycol in the film is 5 with respect to all ester bonds.
A photographic support characterized by being at most mol%. 2. The photographic support according to claim 1, wherein the copolymerized polyester contains polyalkylene glycols as a monomer unit. 3. The photographic support according to claim 1, wherein the copolyester further has an aliphatic dicarboxylic acid having 4 to 20 carbon atoms as a monomer unit. 4. The copolyester is obtained by adding at least one selected from the group consisting of sodium acetate, sodium hydroxide and tetraethylhydroxyammonium during transesterification and / or polymerization. The photographic support according to any one of 1 to 3.