EP0681211B1

EP0681211B1 - Process for preparing a photographic support

Info

Publication number: EP0681211B1
Application number: EP95302039A
Authority: EP
Inventors: Takatoshi Yajima; Mami Ishii
Original assignee: Konica Minolta Inc
Current assignee: Konica Minolta Inc
Priority date: 1994-03-28
Filing date: 1995-03-27
Publication date: 2001-12-12
Anticipated expiration: 2015-03-27
Also published as: EP0681211A1; DE69524474D1

Description

FIELD OF THE INVENTION

The present invention relates to a process for preparing a photographic support comprising a biaxially oriented polyester film which has excellent mechanical strength and dimensional stability and reduced remaining curl.

BACKGROUND OF THE INVENTION

Recently, applications of photographic light-sensitive material (hereinafter, referred to as simply a light-sensitive material) has been diversified. As a result, improvement of unwinding of film in photographing, enhancement of photographing magnification and downsizing of photo-taking units have been advanced. Therefore, for a support of a photographic light-sensitive material, excellent mechanical strength and dimensional stability have been demanded. In addition, in the case of a roll film type photographic light-sensitive material, reduction of the diameter of the roll core is critical.
In the case of a roll film photographic light-sensitive material such as conventional color negative film, triacetyl cellulose film (hereinafter referred also as TAC film) has been used. However, the mechanical strength of TAC film is weak and dimensional change due to moisture absorption is large. Therefore, it has been impossible to reduce the thickness of a film. In addition, when the roll core is reduced, remaining curl is enhanced. Accordingly, poor conveyance in a pre-splicing step before photographic processing has come to be a new problem. In other words, in a photo-finishing laboratory processing film in large amounts, exposed photographic films are not processed one roll by one. Several rolls are spliced to make a long roll, and processed as one. When the remaining curl of exposed photographic film is too large, effective splicing of the photographic film becomes difficult.
A polyethylene terephthalate film (hereinafter, referred also as PET film) subjected to biaxial orientation has excellent transparency, mechanical strength and dimensional stability. It is used for micro film when it is necessary to reduce the thickness of the film layer, for graphic arts films wherein dimensional stability is essential and for X-ray films wherein transparency and stiffness are desired.
However, PET film does not have as much curl recovery property after being subjected to photographic processing as TAC film has. When PET film is used for a roll film type photographic light-sensitive material, curl remaining after being subjected to photographic processing is excessive. Accordingly, it is inferior in terms of handling property during separation operations. In addition, for example, during a process of printing images onto a photographic paper after photographic processing, problems such as the occurrence of scratches, fading of focus and jamming during conveyance occur.
In addition, PET film is more difficult to give remaining curl compared to TAC film. However, when the dimension of a roll core is reduced, PET was not satisfactory.
Generally, a polyester film is excellent in terms of mechanical strength and dimensional stability. Accordingly, by reducing the remaining curl of the polyester film typified by PET film, the remaining curl after being developed can also be reduced. Therefore, it is considered that the various above-mentioned problems can be solved.
From the above-mentioned viewpoint, as a method for reducing remaining curl of the polyester film, Japanese Patent Publication Open to Public inspection (hereinafter, referred to as Japanese Patent O.P.I. Publication) No. 16358/1976 discloses a method of heating a thermo-plastic resin film at its Tg-5°C to its Tg-30°C. In addition, Japanese Patent O.P.I. Publication No. discloses a method of heating a polyester film whose Tg is from 90°C to 200°C at 50°C to Tg for 0.1 to 1500 hours after subbing.
A method of heating a thermo-plastic resin film at its Tg-5°C to Tg-30°C for from 0.1 to 1500 hours has an effect to reduce remaining curl of crystalline or semi-crystalline thermo-plastic resins such as PET film and polyethylene naphthalate film (hereinafter referred to as PEN film). This method seemed to be effective. However, the above-mentioned method of heating a film at a relatively high temperature for many hours has a problem of deteriorating the quality of the film.
A light-sensitive material is ordinarily composed of a plastic film on which various functional layers are provided such as an adhesive layer, an anti-static layer and a photographic light-sensitive layer. The production procedure is ordinarily as follows: On a wide and long roll of plastic film, the above-mentioned functional layers are coated, and then, it is wound onto a roll core having a relatively large diameter as an intermediate product. Following this, it is cut into the final product form for packing.
This intermediate product is advantageous when it is as wide and as long as possible in terms of reducing switching time and improving productivity. Therefore, the weight of the intermediate product tends to continuously increased. As a result, the roll core portion bears a considerable load.
Incidentally, it is well known that the coefficient of elasticity of the thermo-plastic resin film is reduced steeply when it is heated in the vicinity of Tg. Therefore, when the thermo-plastic resin film is subjected to heating for a long time in the vicinity of Tg under a condition of noticeable load the film cannot bear the load, so that shrinking, folding and pressure marks are forced to occur. Such surface defects appear as a coating fault and deterioration of film flatness even when they are so fine as to be invisible, when a subbing layer is coated in the succeeding subbing layer coating process. Therefore, such a film practically cannot be used.
A method of heating a polyester film whose Tg is from 90°C to 200°C at from 50°C to the Tg for from 0.1 to 1500 hours is theoretically completely the same as a method described in Japanese Patent O.P.I. Publication No. 16358/1976. Accordingly, in order to reduce remaining curl sufficiently, it is necessary for the film to be heated in the vicinity of the Tg. For example, in the case of a polyester film whose Tg is 90°C, sufficient additional effects cannot be obtained without being heated at 60°C or more. In addition, in the case of a polyester film whose Tg is 120°C, sufficient effects cannot be obtained without being heated at 90°C or more. Therefore, Tg of a polyester film must be high, and the film must be heated at extremely high temperature. Therefore, the following additional problem occurs.
Namely, with regard to a conventional light-sensitive material, the highest temperature used therein is, at highest, 50°C. Use of this light-sensitive material at higher temperature than this must be restricted to a short time. In addition, heat resistance of a subbing layer composed of various functional layers is also designed considering the above-mentioned ordinary temperature condition. Therefore, these subbing layer cannot bear heating processing for reducing remaining curl of a film sufficiently. As a result, various additional problems such as shift of additives to the surface, bleeding out and cracking of the coated surface due to deterioration of raw materials and decomposition.
As explained, above, so far, there has not been discovered a photographic support which is excellent in terms of enhancement of unwinding speed of a film in photographing, mechanical strength and dimensional stability capable of enhancing photographing magnification and downsizing of a photo-taking unit, and which has no conveyance defect in the pre-splicing process, even when the diameter of the roll core is reduced, and is excellent in assortment operability after photographic processing.

SUMMARY OF THE INVENTION

Considering the above-mentioned problems, an object of the present invention is to prepare a photographic support comprising a biaxially oriented polyester film which has excellent mechanical strength and dimensional stability and reduced remaining curl wherein no poor transportability occurs in a pre-splicing process and separation operability is excellent after being subjected to photographic processing even when the dimension of the roll core is reduced.

DETAILED DESCRIPTION OF THE INVENTION

The above problems can be solved by the following:
1. A process for preparing a photographic support comprising a biaxially oriented polymer film, which process comprises subjecting the polyester film to humidity conditioning to have a moisture content of from 0.1 to 1.5% and heat treating the thus obtained support at a temperature of from 15°C to less than (Tg - 5)°C.
2. A process for preparing a photographic support comprising a biaxially oriented polyester which comprises subjecting the film to humidity conditioning to have a moisture content of from 0.1 to 1.5%, and heat treating the thus obtained support at a temperature of from 15°C to less than (Tg - 30)°C.
3. The process of (1) or (2) above, wherein the polyester film comprises an ethyleneterephthalate unit or an ethylene 2,6-naphthalate unit.
4. The process of (1), (2) or (3) above, wherein the polyester film comprises an ethyleneterephthalate unit or an ethylene 2,6-naphthalate unit in an amount of 70% by weight or more.
5. The process of (1), (2), (3) or (4) above, wherein the polyester film comprises two or more layers and at least one of the layers comprises a polyester comprising as a copolymerisation unit, a dicarboxylic acid unit having a metal sulfonate group.
6. A process for preparing a light sensitive material comprising a support and a photosensitive layer, comprising the steps of:
subjecting a support comprising a biaxially oriented polyester film to humidity conditioning to have a moisture content of from 0.1 to 1.5% by weight;
preserving the support at a temperature between 15°C and less than (Tg of the polyester film - 5)°C; and
coating the thus obtained support with at least one light-sensitive layer.
7. A process for preparing a photographic support comprising a biaxially oriented polyester film, which process comprises subjecting the polyester film to humidity conditioning to have a moisture content of from 0.1 to 1.5% and heat treating the thus obtained film at a temperature of from 15°C to (Tg - 30)°C for 0.1 hours or more and then providing at least one subbing layer on the heat treated polyester film.
8. The process of item 7 above, wherein the polyester film comprises mainly an ethyleneterephthalate unit or an ethylene 2,6-naphthalate unit.
9. The process of item 7 or 8 above, wherein the polyester film comprises an ethyleneterephthalate unit or an ethylene 1,6-naphthalate unit in an amount of 70% by weight or more.
The invention will be detailed below:
The polyester constituting a biaxially oriented polyester film prepared according to the invention is not particularly limited, but is preferably a film forming polyester comprising a dicarboxylic acid unit and a diol unit as a main component.
The dicarboxylic acid unit as a main component includes terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalene dicarboxylic acid, 2,7-naphthalene dicarboxylic acid, diphenylsulfone dicarboxylic acid, diphenylether dicarboxylic acid, diphenylethane dicarboxylic acid, cyclohexane dicarboxylic acid, diphenyl dicarboxylic acid, diphenylthioether dicarboxylic acid, diphenylketone dicarboxylic acid, and phenylindane dicarboxylic acid. The diol unit includes ethylene glycol, propylene glycol, tetramethylene glycol, cyclohexane dimethanol, 2,2-bis(4-hydroxyphenyl) propane, 2,2-bis(4-hydroxyethoxyphenyl) propane, bis(4-hydroxyphenyl) sulfone, bisphenolfluorenedihydroxyethylether, diethylene glycol, neopentyl glycol, hydroquinone and cyclohexane diol.
Of the polyesters comprising mainly the above component, polyesters comprising mainly as the main component terephthalic acid and/or 2,6-naphthalene dicarboxylic acid as a dicarboxylic acid unit and ethylene glycol and/or 1,4-cyclohexane dimethanol as a diol unit are preferable in view of transparency, mechanical strength or dimensional stability. Of these polyesters, polyesters comprising mainly as a main component polyethylene terephthalate or polyethylene 2,6-naphthalate or copolyesters comprised of a terephthalic acid, 2,6-naphthalene dicarboxylic acid and ethylene glycol unit are preferable.
The polyester comprising an ethyleneterephthalate unit or an ethylene 2,6-naphthalate unit in an amount of 70% by weight or more gives a film highly excellent in view of transparency, mechanical strength or dimensional stability. It is well known that a polyester film comprising as a main component polyethylene 2,6-naphthalate is superior in mechanical strength or heat resistance to one comprising as a main component polyethylene terephthalate. However, the polyester film comprising as a main component polyethylene 2,6-naphthalate has drawbacks such as fluorescence and high price.
Accordingly, one comprising as a main component polyethylene terephthalate is usually used, and one comprising as a main component polyethylene 2,6-naphthalate is optionally used when used as a thinner film or under high temperature. Further, a mixture thereof can compensate for each drawbacks.
The polyesters useful in the process of the invention constituting a biaxially oriented polyester film may contain other copolymerizable units and may mix with other polyesters as far as it does not inhibit the effects of the invention. Examples thereof include the above described dicarboxylic acid or diol unit and polyesters composed thereof.
The polyester constituting the polyester film prepared according to the present invention is desirable because appropriate moistureabsorption properties can be obtained by copolymerizing at least one kind of a compound having at least one hydrophilic group and incorporation of appropriate moisture in a film becomes easy in the heating process described later.
As a hydrophilic group having at least one hydrophilic group, a sulfonic acid, a sulfinic acid, a phosphoric acid, a carboxylic acid or its salts, a polyoxyalkylene group, a sulfamoyl group, a carbamoyl group, an acylamino group, a sulfonamide group, a disulfonamide group, a ureido group, a urethane group, an alkylsulfonyl group and an alkoxysulfonyl group are cited. Of these, a sulfonic acid, a sulfinic acid, a phosphoric acid, a carboxylic acid or its salts, a polyoxyalkylene group and a disulfonamide group are desirable.
The compound having a hydrophilic group includes an aromatic dicarboxylic acid having a sulfonate group and its ester derivative, a dicarboxylic acid having a polyoxyalkylene group and its ester derivative or a diol having a polyoxyalkylene group in view of prevention of delamination. In view of transparency or polymerizability are preferable 5-sodiumsulfoisophthalic acid, 2-sodiumsulfoterephthalic acid, 4-sodiumsulfophthalic acid, 4-sodiumsulfo-2,6-naphthalene dicarboxylic acid, a compound wherein the sodium is substituted with an other metal atom (for example, potassium or lithium), ammonium or phosphonium and ester derivatives thereof, polyethylene glycol, polytetramethylene glycol or polyethylene glycol-polypropylene glycol. A copolymer containing the above monomer unit or a polymer in which the hydroxy groups at the ends of the copolymer are oxidized to carboxy groups is preferable.
With regard to the above-mentioned compounds respectively having a hydrophilic group, one kind may be used independently or two or more kinds may be used in combination. Both of an aromatic group dicarboxylic acid component having a sulfonate group in a polyester and a compound component having a polyoxyalkylene group are copolymerized, it is so desirable that moisture-absorption property is further improved.
The copolymerization content of the aromatic group dicarboxylic acid component having a sulfonate group is preferably from 0.5 to 10 mol% based on a difunctional dicarboxylic acid constituting polyester.
The number average molecular weight of a component having the polyoxyalkylene group is preferably from 300 to 20000. In addition, a range of from 600 to 10000 is more desirable and a range of from 1000 to 5000 is most desirable. Its copolymerization content is desirably from 0.5 to 15 wt% against the polyester of the reaction-produced product.
In order to improve heat resistance of a film, a bisphenol compound or a compound having a naphthalene ring or a cyclohexane ring may be copolymerized. The copolymerization ratio of the above compound unit in the copolymer is preferably from 1 to 20 mol% based on the total dicarboxylic acid unit of the copolymer.
The polyester used in the process of the invention may contain an oxidizing agent. The oxidizing agent is effective in a polymer comprising a polyoxyalkylene unit. The oxidizing agent is not particularly limited to the kinds and various oxidizing agents may be used. Examples thereof include a hindered phenol compound, a phosphite and a thioether. In view of transparency a hindered phenol compound is preferred.
The content of the oxidizing agent in the polyester is from 0.01 to 2% by weight, and preferably from 0.1 to 0.5% by weight. The content of the oxidizing agent within the above range prevents fog phenomenon having high density at unexposed portions or lowers a film haze. Therefore, a transparent photographic support is obtained. The oxidizing agents may be used alone or in combination.
The polyester used in the process of the invention preferably comprises dyes in order to prevent light piping phenomenon. As the dyes used for this object, there is no limitation to the kinds thereof, but anthraquinone or perinone type dyes are preferable in view of heat resistance in the course of manufacturing a film.
With regard to color tone of the film, gray dyes as used in ordinary light sensitive materials are preferable. Dyes such as MACROLEX (RTM) produced by Bayer Co., SUMIPLAST (RTM) produced by Sumitomo Kagaku Co., Ltd. and Diaresin produced by Mitsubishi Kasei Co. Ltd. can be used alone or in combination to form the desired color tone. The dyes are preferably incorporated in the film to have a 60 to 85% spectral transmittance of from 600 to 700 nm and a difference between the maximum and minimum transmittance of not more than 10% in order to prevent the light piping phenomenon and to obtain excellent photographic prints.
To the biaxially-oriented polyester film, smoothness can be provided if necessary. There is no specific limitation to a smoothness-providing means. However, a particle addition method wherein an inert inorganic particle is added to the polyester, a particle precipitation method wherein a catalyst added in the synthesis of the polyester is precipitated or a method to coat a surfactant on a film surface is conventional. Of them, the particle precipitation method which can control the precipitated particle to a relatively small range is preferred, because smoothness can be provided without deteriorating the transparency of the film. As a catalyst, various conventional catalysts can be used. Specifically, those containing Ca and Mn are preferred because high transparency can be retained. These catalysts may be used independently, or two or more catalysts may be used in combination.
The constitution of the biaxially-oriented polyester film prepared according to the present invention may be of poly layers composed of different kinds of polyesters. For example, provided that a layer composed of polyester whose main component is ethylene terephthalate unit or ethylene-2,6-naphthalate unit is defined to be A layer and layers composed of other polyesters are defined respectively be B layer and C layer, a two-layer structure composed of A layer and B layer is allowed. Three layers structures such as A layer/B layer/A layer, A layer/B layer/C layer, B layer/A layer/B layer or B layer/A layer/C layer are allowed. In addition, a constitution having 4 or more layers is allowed, of course. However, this is not practically preferable, because production facilities become too complicated. It is preferred that the thickness of the A layer is 30% or more compared to the total thickness of the polyester film, but 50% or more is more preferable.
The transparency, mechanical strength and dimensional stability of an entire film can be improved by the use of polyethylene terephthalate, polyethylene naphthalate or other homopolyesters or other copolymer polyesters that are excellent in terms of transparency, mechanical strength and dimensional stability, and may be used as the polyester constituting the B layer or the C layer.
In addition, when the biaxially-oriented polyester film has a multilayered constitution, provision of functions such as the above-mentioned prevention of oxidation, prevention of light-piping and smoothness and addition of various additives other than the above-mentioned materials may be applied only to the surface layer. Therefore, transparency of a film may be kept high.
Precipitation of oligomer onto the surface of a film can be prevented strictly by laminating on both sides of the biaxially-oriented polyester film a layer composed of another polyester. In this case, as the polyester constituting a layer composed of another polyester (polyester D) laminated on both sides, it is preferred to use the above-mentioned polyester. The Tg of the polyester D is preferably higher than the Tg of the inner polyester. The Tg of the polyester D is preferably higher than the Tg of the inner polyester by 5°C or higher and more preferably higher by 15°C or more. The layer composed of the polyester D is necessarily thin in a certain range of thinness in order to retain the moisture-absorption property of the film. The thickness is preferably from 0.05 to 10µm.
There is no specific synthesis method for a raw material polyester of the biaxially-oriented polyester film. It can be produced in accordance with the conventional polyester production method. For example, a direct ester method, where a dicarboxylic acid component is subjected to direct esterization-with a diol component and an ester exchange method wherein dialkylester as a dicarboxyl acid component and a diol component are subjected to an ester exchange reaction, the resulting material is heated under evacuating conditions so that excessive diol component is removed for copolymerizing can be used. In this instance, an ester-exchange catalyst, a polymerization reaction catalyst or an anti-heat stabilizer can be added. In addition, during each processing of synthesizing, an anti-coloration agent, an anti-oxidation agent, a crystal nuclei agent, a lubricant, a stabilizer, an anti-blocking agent, a UV absorber, a viscosity regulator, an anti-foaming agent, a transparency agent, an anti-static agent, a pH regulator, a dye and a pigment may also be added.
The remaining curl of the biaxially-oriented polyester film is preferably 110m^-1 when calculated by the following method. When the remaining curl of the film is too large, conveyance property in the pre-splicing process and operability in the separating operation become problematic. In addition, it is preferred that there is an appropriate remaining curl because it is easier to feed the end of a film from a film cartridge and the thrusting property becomes superior. Therefore, the more preferred range of remaining curl is from 5 to 90m^-1.

A light-sensitive material having a width of 35mm and a length of 1200mm was subjected to humidity conditioning for one day at 23°C and 55%RH. With its photographic light-sensitive layer side inside, the light-sensitive material was wound on a roll core having a diameter of 7mm and fixed to the core so as not return. Next, this film was housed into a cartridge case made of polyethylene and heated for 4 hours at 50°C and 20%RH, and then, left for one hour at 23°C and 55%RH. Following this, the film was released from the roll core. The external edge of a film roll was clipped and hung. In this state, the film was left for one hour at 23°C and 55%RH. Then, the degree of curling at the bottom of the film is calculated in terms of inverse of curvature radius. The unit of measure is m^-1.
There is no specific limitation to the thickness of the biaxially-oriented polyester film used in the process of the present invention. It may be altered so that it has necessary strength in accordance with its specific application. Specifically, when a film is used for a photographic light-sensitive material for color negative film, it is preferred to be from 20 to 125 µm and more preferred to be from 40 to 90 µm. In addition, when the film is used for medical use or graphic art film use, it is preferred to be from 50 to 200 µm and more preferred to be from 60 to 150 µm. When the film is less than the above-mentioned range, the necessary strength may not be obtained. On the other hand, when the film is thicker than the above-mentioned range, any superiority to conventional support for a light-sensitive material is lost.
To the biaxially-oriented polyester film, it is desirable to provide curling in a transversal direction in terms of obtaining a photographic light-sensitive material not causing the occurrence of scratches or an out-of-focus effect during the process of printing on a photographic paper. Incidentally, the above-mentioned effect is displayed when a photographic light-sensitive layer is provided on the convex side of the curling of a film and the film is wound with aforesaid surface to the inside.
The transversal direction herein refers to a direction perpendicular to a direction rolled in a rolled film which is not the thickness direction.
The degree of curling provided to the film for the above-mentioned purpose cannot be determined overwhelmingly because it is dependent on the film thickness, coefficient of elasticity and moisture-absorption swelling coefficient of the photographic light-sensitive layer. It may be provided as flat as possible in a range that the photographic light-sensitive layer side is not convex when a photographic light-sensitive layer is prepared. Ordinarily, under conditions of 23°C and 20%RH, it is 5m^-1 to 50m^-1. The degree of curling is calculated in the following manner.

A test sample cut 35mm in the width direction and 2mm in the longitudinal direction in a rolled film was subjected to humidity conditioning at 23°C and 20%RH for one day. Following this, the curvature radius of curl in a transversal direction of the sample is calculated in terms of meter. The curl degree in the transversal direction is represented by its inverse. The unit is m^-1.
The transversal direction referred to herein, means a right angle (provided that a direction of film thickness is eliminated) to a roll direction when a photographic light-sensitive material is used in a roll form. A lateral direction means the roll direction. Since roll direction is a long roll, it is desirable to set a machine direction in producing a film to be a length direction.
There is no limitation to a method to provide curling in a transversal direction. For example, a method to laminate polyesters having different copolymer components and main constitution components to each other, a method to laminate the same or different polyesters respectively having different intrinsic viscosities, a method to have a three-layer structure and to change the thickness of both outer layers and a method to change orientation condition and heat fixing condition of the front and rear side and to give dispersion of molecule orientation and the degree of crystallization in a direction of the thickness of a film are cited. In addition, there is a method of processing with a chemical such as resolsine. In addition, it goes without saying that it is possible to mix the above-mentioned methods appropriately and to provide the above-mentioned methods in a layer constitution of four layers or more.
Of them, a method having a two-layer constitution wherein the main constitution components are the same and the copolymer components are different from each other and a method having a three-layer constitution wherein the main constitution components of the center layer and both outer layer are the same, copolymer components between them are different from each other and the thickness of both outer layers is changed are preferred because the degree of curling is easily adjusted. When the thickness of both outer layers is changed for the above-mentioned purpose, it is preferred to be 1.1≤ d1/d2, provided that the thickness of both outer layers are defined to be d1 and d2. In the case of a film not included in the above-mentioned range, it may be difficult to be oriented.
In addition, the Haze of the biaxially-oriented polyester film is preferably 3% or less. It is more preferably 1% or less. When the Haze is larger than 3%, in the case that a film is used as a support for a light-sensitive material, images printed on a photographic paper become faded and unclear. The above-mentioned Haze is measured in accordance with ASTM-D1003-52.
Tg of the biaxially-oriented polyester film is preferably 60°C or more, and more preferably 70°C or more. Tg is calculated as a mean value of temperature at which the base line measured by a differential scanning calorimeter starts to be deviated and temperature at which the deviation returns to the base line. When Tg is the above-mentioned value or higher, film shows no deformation in the drying process in a processing machine. Accordingly, a light-sensitive material having small remaining curl after photographic processing is obtained.
Next, the production method of the invention for preparation of the polyester film will be explained.
As a method for obtaining an unoriented sheet and a method for subjecting a sheet to a mono-axial orientation in a machine direction, conventional methods can be used. For example, raw material polyester is molded in a pellet state. It is subjected to hot air drying or vacuum drying. Following this, it is melted and extruded wherein it is extruded in a sheet state from a T die. It is brought into contact with a chilling drum by means of an electrostatic method, and then, it is cast to obtain an unoriented sheet. Next, the resulting unoriented sheet is heated to a range from a glass transition temperature (Tg) of the polyester to Tg + 100°C through a heating device such as plural rolls and/or an infrared heater for orienting laterally in one step or multiple steps. The longitudinal stretching ratio is ordinarily in a range from 2.5 times to 6 times. It is necessary to be in a range to achieve transversal orientation. In setting the stretching temperature when a sheet is of multilayered structure, it is preferred that the highest Tg among the Tgs of the polyester of each constituting layer is set as the Tg.
In this occasion, lamination of the polyester may be conducted by means of a conventional method. For example, a co-extrusion method using a plural extruder and a feed-block type die or a multi-manifold type die, a extrusion lamination method wherein, on a mono-layer film constituting laminated layers or a laminated film, an other resin constituting other laminated layers is melted and extruded from an extruder and the resin is chilled and solidified on a chilling drum and a dry lamination method wherein a mono-layer film constituting laminated layers or a laminated film is laminated through an anquor agent or an adhesive agent if necessary are cited. Of them, the co-extrusion method wherein the number of production process is small and adhesivity between each layer is desirable is preferable.
Next, the polyester film subjected to mono-axial orientation in the machine direction obtained in the above-mentioned manner was subjected to transverse orientation in a temperature range from Tg to Tm-20°C. Next, it was subjected to heat-set. The transversal stretching ratio is ordinarily from 3 to 6 times. In addition, the ratio of the longitudinal orientation magnification and the transverse orientation magnification was adjusted appropriately by measuring the physical properties so that the film had desirable properties. In the case of the present invention, the modulus of elasticity in the transversal direction is caused to be greater than the modulus of elasticity in the longitudinal direction. In accordance with application, the ratio may be changed. In this occasion, when the film is subjected to transversal orientation while increasing the difference of temperature between oriented regions divided into two or more regions in a range from 1 to 50°C, it is preferred that the dispersion of the physical properties in the lateral direction is reduced. In addition, after transversal orientation, when the temperature of film is kept in a range from the final transversal orientation temperature or lower and Tg-40°C or higher, it is desirable that the dispersion of the physical properties in the lateral direction can be reduced.
Regarding heat fixing, the film is subjected to heat fixing ordinarily from 0.5 to 300 seconds in a temperature range from the final transversal orientation temperature or higher to Tm-20°C or lower. In this occasion, in 2 or more separate regions, the difference of temperature is enhanced gradually in a range of 1 to 100°C for heat fixing.
The film subjected to heat fixing is chilled ordinarily to Tg or lower. The clip held portions at both ends of film are cut off and the film is wound. In this occasion, it is preferred that the film is loosened in the longitudinal direction and/or transversal direction by 0.1 to 10% of the temperature range of the final heat fixing temperature or lower and Tg or higher. In addition, with regard to chilling, it is preferred that the film is chilled gradually from the final heat fixing temperature to Tg at a chilling rate of 100°C or less per second. There is no limitation to chilling and loosening means. Any conventional means is acceptable. It is desirable that these processes are conducted while chilling in several temperature drops gradually, to retain the dimensional stability of the film. Incidentally, the chilling speed is calculated by the equation (T₁-T_g)/t, provided that the final heat fixing temperature is T₁ and the time from the final heat fixing temperature to Tg is t.
The above-mentioned appropriate conditions for heat fixing, chilling and loosening are different depending upon the kind of polyester constituting the film. Therefore, they may be determined by adjusting appropriately by measuring the physical property of the resulting biaxially-oriented film so that the film acquires desirable characteristics.
In addition, in producing the above-mentioned film, functional layers such as an anti-static layer, a lubricant layer, an adhesive layer and a barrier layer may be coated before and/or after orientation. In this occasion, various surface processing methods such as corona discharge and chemical processing may be added as desired. In addition, in order to improve strength, conventional orientation for an oriented film such as a multi-step longitudinal orientation, a relongitudinal orientation, a re-longitudinal-transversal orientation and a transversal-longitudinal orientation may be considered. It is without saying that the cut off clip holding portion at both ends of the film cut may be recycled as a raw material for the same kind of film or as raw material for a different kind of film after crushing processing or, if necessary, after granulating processing, depolymerization or repolymerization processing.
The biaxially-oriented polyester film obtained in the above-mentioned manner tends to have a remaining curl. In the present invention, a biaxially-oriented polyester film is subjected to humidity conditioning to have a moisture content of 0.1 to 1.5 wt%, and then is heat treated at 15°C to (Tg - 5)°C. The humidity conditioned polyester film is preferably heat treated at 15°C (Tg - 30)°C for not less than 0.1 hours. When a film is multilayered, the layer which shows the lowest Tg value among the polyester films constituting a layer substantially bearing a film is used as the standard.
Incorporating a small amount of moisture in a hydrophobic polyester is considered to have no relation to curl, however, it is surprising that the incorporating can provide a sufficient remaining curl reduction effect even when it is heated at a lower temperature than the conventional one. When moisture of film in processing is small, a sufficient remaining curl reduction effect cannot be obtained. When it is too large, coating defect after coating a subbing layer cannot be eliminated. Incidentally, moisture content and Tg are calculated as follows.

The moisture content may be measured by any conventional method, and is measured at a temperature of 150°C by the use of a micro moisture meter (for example, Model CA-05, produced by Mitsubishi Kasei Co., Ltd.).

In a nitrogen air flow of 300 ml/minute, 10 mg of film is melted at 300°C. Immediately following this, the film is chilled in liquid nitrogen quickly. This quickly-chilled sample was measured by a differential scanning calorimeter (Model DSC8230, produced by Rigaku Denki co., Ltd.). In nitrogen air flow of 100 ml per a minute, the temperature was elevated at a rate of 10°C per minute to detect Tg. Tg is a mean value between the temperature at which the base line starts deviation and the temperature at which the deviation returns to the base line again. Incidentally, the measurement starting temperature is by 50°C or more lower than the Tg.
The higher the processing temperature, the more the remaining curl reduction effect is. However, when the temperature is too high, shrinkage, pressure marks and folding of the film easily occur. Therefore, coating defect after coating a subbing layer cannot be eliminated. When the processing temperature is low, a longer processing time is necessary. However, when the processing temperature is too low, sufficient remaining curl reduction effect cannot be obtained. With regard to the processing time, the remaining curl reduction effect can be obtained from 0.1 hour or more. The longer the time is, the higher the effects which can be obtained. Therefore, the time can be set appropriately so that a desired effect may be obtained. However, when the time is too long, productivity becomes inferior. Therefore, up to 1500 hours is ordinarily preferred.
There is no limitation to incorporate an appropriate moisture to polyester film. For example, a method to prevent contact of films by providing emboss processing partially at an arbitrary position such as the edge of film and the central portion or throughout the whole length, a process to fold the edge portion and thickening the thickness of the film partially and to regulate humidity necessarily in a room provided with air-conditioning, a method to insert a material having favorable moisture-absorption property such as paper between films in winding and a method to blow humidified air in winding are cited. Of them, the method to provide emboss processing is the most preferable because it is simplest and surest. Off course, the above-mentioned methods may be used in combination. for the above-mentioned purpose, emboss processing is preferred to be processed so that concave and convex of ordinarily 10 to 100 µm may be made.
There is no limitation to the kind of core winding. It is desirable that it provides strength not causing loosening when a film is wound, appropriate moisture vapor transmitting property or fine unevenness on its surface so that the atmosphere reaches a core central portion. As examples thereof, paper roll, resin roll, fiber-strengthened resin roll, metal roll with a groove, mesh roll and ceramic roll are cited. When the diameter of the core is too small, shrink are easily occurs at the core central portion. Therefore, it is preferred that it is large to a certain extent. Ordinarily, it is desirable to be 75mm or more and it is more desirable to be 200mm or more.
Since the diameter of the roll of film roll wound is too large, even processing becomes difficult. Therefore, the roll diameter is desirable to be small to a certain extent. It is ordinarily 1000 mm or less and desirably 850 mm or less.
In order to assure the effects of the present invention more firmly, it is desirable to envelop the film roll with a vapor barrier type material when the film is caused to incorporate an appropriate moisture. As a vapor barrier type material, there is no specific limitation. It is suitable if is bears temperature at heating. Examples thereof include various films such as polyethylene, polypropylene and polyester and films on which metal is deposited. The thickness is preferably from 5 to 1000 µm.
In the present invention, a photographic support is preferably obtained, by coating at least one subbing layer on a surface of a film after the above-mentioned processing, which has no coating defects and is excellent in terms of flatness after coating the subbing layer. The reason in detail is unknown. However, it is considered to be a multiplication effect of that the surface defect of the film is strictly restricted compared to convention remaining curl reduction method due to heat processing in the vicinity of Tg of film and that the subbing layer is coated under circunstances wherein the moisture amount in a film is appropriately adjusted.
When a hydrophilic photographic emulsion layer is coated directly on a hydrophobic film such as a polyester film, it is usual that the necessary adhesive force cannot be obtained. Therefore, it is ordinarily necessary to coat a subbing layer on the surface of the film. There is no limitation to the material usable for the subbing layer, but the material may include copolymers whose starting raw material is vinyl chloride, vinylidene chloride, butadiene, methacrylic acid, acrylic acid, itaconic acid or maleic anhydride, polyethylene imine, polyester, polystyrene, polyurethane, epoxy resins, grafted gelatin and nitro cellulose and their mixture.
In the above-mentioned subbing layer, one or two or more various additives such as a surfactant, an anti-static agent, an anti-halation agent, a crossover-cutting agent, a coloration dye, a pigment, a viscosity increasing agent, a coating aid, an anti-foggant, an anti-oxidation agent, a UV absorber, a UV stabilizer, an etching processing agent, magnetic powder and a matting agent may be added.
There is no limitation to a method for coating the subbing layer. Various methods known conventionally can be used. For example, the above-mentioned materials are dissolved in a solvent to make a solution or a dispersed solution. By the use of an air-knife coater, a dip coater, a curtain coater, a wire bar coater, a graveure coater and an extrusion coater, they are coated and dried. In this case, if necessary, methods to subjecting to surface activation processing such as corona discharge processing, UV processing, glow discharge processing, plasma processing and fire processing and methods to subjecting to etching processing such as resolsine processing, phenols processing, alkaline processing, amine processing and trichloro acetic acid processing are desirably used. In addition, from the viewpoint of operation environment, the coating solution is desirably water dispersion solution or an aqueous solution.
The subbing layer may be composed of one layer or two or more layers. It may contain, in addition, an anti-static layer, a lubricant layer, a barrier layer, an anti-halation layer, a cross-over cutting layer, a UV absorber layer and a magnetic recording layer.
The film wherein the subbing layer is coated in the above-mentioned manner is chilled to room temperature and wound. It is stored until it is subjected to the following step. In this case, when the moisture ratio of the film is regulated to 0.2% or less, it is desirable that curling due to storage can be prevented.
Next, a method for forming a light-sensitive material will be explained.
A light-sensitive material is prepared by providing, on at least one side of the photographic support prepared according to the present invention, a photographic emulsion layer. The photographic emulsion layer is formed by coating a silver halide emulsion. The photographic emulsion layer can be formed on one side or on both sides of the photographic support. In addition, the photographic emulsion layer may be provided in one or two or more layers on each side. The silver halide emulsion can be coated directly on a photographic support or through another layer, for example, a hydrophilic layer not containing a silver halide emulsion. In addition, the silver halide emulsion layer can be coated dividedly into plural silver halide photographic light-sensitive 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. In addition, on the silver halide emulsion layer and at arbitrary places between the intermediate layer or the silver halide emulsion layer and the photographic support, nonsensitive layers such as a hydrophilic colloidal layer, a protective layer, an anti-halation layer, a backing layer and a masking layer may be provided.
The silver halide emulsion used in the process of the present invention can be prepared by methods described in "1. Emulsion preparation and types" of Research Disclosure (hereinafter, abbreviated as RD) No. 17643, pp. 22 to 23 (December, 1979) and RD No. 18716, on page 648, P. Glkides, Chimie et Phyzique Photographique, Paul Montel, 1967), "Photographic Emulsion chemistry" written by Daffin, Focal Press, 1966) and V. L. Zelikman etal, Making and Coating Photographic Emulsion, focal Press, 1964).
As a silver halide emulsion used in the process of the present invention, other suitable mono-dispersed emulsions are described in U.S.P. Nos. 3,574,628 and 3,665,394 and British Patent No. 1,413,748.

To a silver halide emulsion used in the process of the present invention, physical ripening, chemical ripening and spectral sensitization may be provided. Additives used in the above-mentioned processes are described in RD Nos. 17643, 18716 and 308119 (hereinafter, referred to as RD17643, RD18716 and RD308119). Table 1 shows places where they are described.

Item	RD308119	RD17643	RD18716
Chemical sensitizer	page 996III-A	page 23	page 648
Spectral sensitizer	page 996IV-A, B, C, D, I and J	pp. 23-24	pp. 648-9
Super sensitizer	page 996IV-A-E and J	pp. 23-24	pp. 648-9
Anti-foggant	page 998VI	pp. 24-25	page 649
Stabilizer	page 998VI	pp. 24-25	page 649

When the photographic light-sensitive material prepared according to the present invention is a color photographic light-sensitive material, suitable photographic additives are described in the above-mentioned RDs. Table 2 shows related places where they are described.

Item	RD308119	RD17643	RD18716
Anti-color agent	page 1002VII-I	page 25	page 650
Dye image stabilizer	page 1001VII-J	page 25
Brightening agent	page 998V	page 24
UV absorber	page 1003VIII-C	pp. 25-6
	XIII-C
Light absorber	page 1003VIII	pp. 25-6
Light scattering agent	page 1003VIII
Filter dye	page 1003VIII	pp. 25-6
Binder	page 1003IX	page 26	page 651
Anti-static agent	page 1006XIII	page 27	page 650
Hardener	page 1004X	page 26	page 651
Plasticizer	page 1006XII	page 27	page 650
Lubricant	page 1006XII	page 27	page 650
Activator/Coating aid	page 1005XI	pp. 26-7	page 650
Matting agent	page 1007XVI
Developer (contained in the light-sensitive material)	page 1011XX-B

When the photographic light-sensitive material prepared according to the present invention is a color photographic light-sensitive material, various couplers can be used. Practical examples thereof are described in the below-mentioned RDs 17643 and 308119. Table 3 shows related places where they are described.

Item	RD 308119	RD 17643
Yellow coupler	page 1001VII-D	page 25VII-C-G
Magenta coupler	page 1001VII-D	page 25VII-C-G
Cyan coupler	page 1001VII-D	page 25VII-C-G
Colored coupler	page 1002VII-G	page 25VII-G
DIR coupler	page 1001VII-F	page 25VII-F
BAR coupler	page 1002VII-F
Other couplers releasing a useful residual group	page 1001VII-F
Alkaline-soluble coupler	page 1001VII-E

In addition, these additives can be added to a photographic light-sensitive layer by means of a dispersion method described in RD No. 308119, on page 1007, Item XIV.
When the photographic light-sensitive material prepared according to the present invention is a color photographic light-sensitive material, an auxiliary layer such as a filter layer and an intermediate layer described in the above-mentioned RD 308119 Item VII-K can be provided.
When the above-mentioned color photographic light-sensitive material is structured, various layer structures such as an ordinary layer, a reverse layer and a unit structure described in the above-mentioned RD 308119, Item VII-K can be used.
For subjecting the photographic light-sensitive material prepared according to the present invention to photographic processing, conventional developing agents described in The Theory of The Photographic Process Fourth Edition, pp. 291 to 334 and journal of the American Chemical Society, Volume 73, page 3,100 (1951) can be used. In addition, the above-mentioned color photographic light-sensitive material can be subjected to photographic processing by means of an ordinary method described in RD 17643, pp. 28 to 29, RD 18716, page 615 and RD 308119, XIX.

EXAMPLES

Hereunder, the present invention will be explained in detail referring to examples. However, the embodiments of the present invention is not limited thereto.

Example 1

In the following example, evaluation of density, glass transition temperature and melting point, film haze, moisture content, intrinsic viscosity, modulus of elasticity and tensile strength, coefficient of thermal shrinkage, curling degree in the transvesal direction, remaining curl value, coating or flatness fault after coating a subbing layer, pre-splicing conveyance property and separation operability was measured as follows.

(1) Density

A film subjected to humidity conditioning was regulated at 23°C and 55%RH for 8 hours was charged into a density grading tube (n-heptane-tetrachlorocarbon). After 24 hours, graduation of the position of film is read. Concurrently, the graduation of the position for the standard sphere is also read so that a calibration line is prepared. Thus, the density is calculated. The unit is g/cm³.

(2) Glass transition temperature Tg and melting point Tm

In nitrogen air flow of 300 ml per a minute, 10 mg of a film or a pellet was melted at 300 °C. Immediately after that, it was chilled abruptly in liquid nitrogen. This abruptly-chilled sample was set to a differential scanning calorimeter (Model DSC8230, produced by Rigaku Denki Co., Ltd.). In nitrogen air flow at 100 ml per minute, the temperature of sample was elevated at a rate of 10°C per minute so that Tg and Tm were detected. Tg is a mean value between temperature at which the base line starts deviation and temperature at which deviation returns to the base line again. Tm is peak temperature of its heat absorption peak. Incidentally, measurement starting temperature is lower than Tg measured by 50°C or lower.

(3) Film haze

In accordance with ASTM-D1003-52, the film haze was measured.

(4) Intrinsic viscosity

A film or a pellet was dissolved in a mixed solvent of phenol and 1,1,2,2-tetrachloroethane (the weight ratio of 60/40) to obtain a solution having a concentration of 0.2 g/dl, 0.6 g/dl or 1.0 g/dl. By the use of a Ubbelohde's viscometer, specific viscosity (ηsp) of each solution at 20°C was measured. Next, ηsp/C was plotted to C. The resulting line was extrapolated to zero of the concentration as the following equation,
Thus, intrinsic viscosity is calculated. The unit is dl/g.

(5) Modulus of elasticity and rupture strength

The film was cut to width of 10 mm and length of 200 mm. The humidity thereof was regulated at 23°C and 55%RH for 12 hours. Following this, by the use of a Tensilone (RTA-100) produced by Orientec Co., Ltd., length between chucks was 100 mm and pulling test was conducted at pulling speed of 100 mm/minute so that modulus of elasticity and rupture strength were measured.

(6) Coefficient of thermal shrinkage

From the film, a sample of 150 mm x 150 mm was picked up. Under the conditions of 23°C and 55%RH, the humidity of the sample was regulated. Following this, lines with an interval of 100 mm was inputted. Then, the resulting sample was heat treated for 30 minutes at 130°C. After regulating the humidity under the conditions of 23°C and 55%RH for one day, the interval of lines was measured. By measuring the difference of the interval of the lines before and after the heat treatment, it was represented by percentage to the interval before the heat treatment. Incidentally, shrinkage was defined to be + and an extension was defined to be -.

(7) Curling degree in the transversal direction

A sample having width of 35 mm and length of 2 mm was prepared. The sample was subjected to humidity conditioning for one day at 23°C and 20%RH. Following this, the curvature radius of curling in the transversal direction of the sample was calculated in terms of meter. The curling degree in the transversal direction was represented by its inverse. The unit is m^-1.

(8) Coefficient of moisture-absorption swelling

By means of a thermal mechanical property measurer (Model TM-7000, produced by Shinkuu rikou Co., Ltd.), the extension of the dimension was measured when humidity was changed from 10%RH to 90%RH at 23°C. The unit is cm/cm·%RH.

(9) Moisture content

By the use of a fine amount moisture meter (Model CA-05, produced by Mitsubishi Kasei Co., Ltd.), the moisture content was calculated at drying temperature of 150°C.

(10) Remaining curl

A photographic light-sensitive material having width of 35 mm and length of 1200 mm was subjected to humidity conditioning for one day under 23°C and 55%RH. Following this, with the photographic light-sensitive layer side inside, the photographic light-sensitive material was wound on a roll core having a diameter of 7 mm and fixed so that it does not return. Next, this film was housed in a cartridge case made of polyethylene, and heated for 4 hours under 50°C and 20%RH. In addition, it was left for one hour under 23°C and 55%RH. Next, the film was released from the roll core, clipped with the outernal edge of the roll of film at top for hanging, and was left for one hour under 23°C and 55%RH. Following this, the degree of remaining curl at the lower edge of the film was measured by the inverse of curvature radius. The unit was m^-1.

(11) Coating fault

The number of surface defect per m² of film was evaluated visually. Ranking was provided under the following criteria. This ranking was determined by the tolerance of quality as a light-sensitive material. Ranking O or higher is necessary for practical use.

Rank Number of surface defect

o ○ 0

○ 1 - 3

× 4 or more

(12) Flatness

A film was subjected to humidity conditioning under 23°C and 55%RH for 12 hours. Thereafter, the film was spread on a flat disc. The degree of waving was checked visually. It was ranked as the following criteria. Incidentally, practicality of this ranking was determined by the tolerance of the quality as a light-sensitive material. It is necessary to be rank O or higher.

Rank Degree of waving

o ○ excellent

○ Slight waving is observed

× waving is remarkable

(13) Pre-splicing conveyance property

In the same manner as in the measurement of the above-mentioned remaining curl; a photographic light-sensitive material was inserted to a Noritsu pre-splicer PS-35-1 (produced by Noritsu Kouki Co., Ltd.) so that its roll core side may take the lead. In each sample, 10 rolls were inserted so that ranking was given under the following criteria by the occurrence of defective conveyance.

Rank The number of occurrence of defective conveyance

o ○ 0

○ 1

× 2 - 10

(14) Separation operability

In the same manner as in the measurement of the above-mentioned remaining curl, a photographic light-sensitive material provided with curling was subjected to photographic processing by the use of a cine type automatic processing machine NCV36 (produced by Noritsu Kouki Co., Ltd.). In each sample, 10 rolls were developed. By means of the conventional method, operation to insert the films into a negative film case was conducted. Under the following criteria, ranking was given.

Rank Operability

o ○ Not problematic

○ Slightly difficult

× Extremely difficult
As stated above, polyester A to polyester F were evaluated.

(Polyester A)

To a mixture of 100 weight parts of dimethyl 2,6-naphthalenedicarboxylate and 60 weight parts of ethylene glycol were added 0.1 weight parts of calcium acetate hydrate and the mixture was subjected to an ester exchange reaction by a conventional method. The reaction product was mixed with 0.05 weight parts of antimony trioxide and 0.03 weight parts of trimethylphosphate. The resulting mixture was gradually heated under reduced pressure, and polymerized at 290°C and at 0.5 mmHg to obtain polyethylene 2,6-naphthalate having an intrinsic viscosity of 0.60.

(Polyester B)

To a mixture of 100 weight parts of dimethyl 2,6-naphthalenedicarboxylate and 60 weight parts of ethylene glycol were added 0.1 weight parts of calcium acetate hydrate and the mixture was subjected to an ester exchange reaction by a conventional method. The reaction product was mixed with 5 weight parts of a 35 weight% 5-sodiumsulfodi(β-hydroxyethyl)-isophthalate ethylene glycol solution, 0.05 weight parts of antimony trioxide and 0.03 weight parts of trimethylphosphate. The resulting mixture was gradually heated under reduced pressure, and polymerized at 290°C and at 0.5 mmHg to obtain polyester having an intrinsic viscosity of 0.55.

(Polyester C)

To a mixture of 100 weight parts of dimethyl terephthalate and 65 weight parts of ethylene glycol were added 0.05 weight parts of magnesium acetate hydrate and the mixture was subjected to an ester exchange reaction by an ordinary method. The reaction product was mixed with 0.05 weight parts of antimony trioxide and 0.03 weight parts of trimethylphosphate. The resulting mixture was gradually heated under reduced pressure, and polymerized at 280°C and at 0.5 mmHg to obtain polyethylene 2,6-naphthalate having an intrinsic viscosity of 0.65.

(Polyester D)

To a mixture of 100 weight parts of dimethyl terephthalate and 65 weight parts of ethylene glycol were added 0.1 weight parts of magnesium acetate hydrate and the mixture was subjected to an ester exchange reaction by an ordinary method. The reaction product was mixed with 5 weight parts of a 35 weight% 5-sodiumsulfodi(β-hydroxyethyl)-isophthalate ethylene glycol solution, 0.05 weight parts of antimony trioxide, 0.03 weight parts of trimethylphosphate, 0.2 weight parts of Irganox 1010® (produced by Ciba Geigy Co. Ltd.) and 0.04 weight parts of sodium acetate. The resulting mixture was gradually heated under reduced pressure, and polymerized at 280°C and at 0.5 mmHg to obtain polyester having an intrinsic viscosity of 0.62.

(Polyester E)

To a mixture of 100 weight parts of dimethyl 2,6-naphthalenedicarboxylate and 60 weight parts of ethylene glycol were added 0.05 weight parts of magnesium acetate hydrate and the mixture was subjected to an ester exchange reaction by an ordinary method. The reaction product was mixed with 30 weight parts of a 35 weight% 5-sodiumsulfodi(β-hydroxyethyl)-isophthalate ethylene glycol solution, 8 weight parts of polyethylene glycol (number average molecular weight 3000), 0.05 weight parts of antimony trioxide, 0.03 weight parts of trimethylphosphate, 0.2 weight parts of Irganox 1010® (produced by Ciba Geigy Co. Ltd.) and 0.04 weight parts of sodium acetate. The resulting mixture was gradually heated under reduced pressure, and polymerized at 280°C and at 0.5 mmHg to obtain polyester having an intrinsic viscosity of 0.55.

(Polyester F)

Polyesters A and C were blended in a tumbler mixer to have a weight ratio of polyester A to polyester C of 80/20.
By the use of each polyester obtained in the above-mentioned manner, films were obtained as follows.

(Film 1)

Polyester A was subjected to vacuum drying at 150°C for 8 hours. Thereafter, it was melted and extruded from a T die in a layer form at 300°C. It was statically brought into contact with a chilling drum at 50°C, chilled and solidified for obtaining an unoriented sheet film. This unoriented sheet film was oriented by 3.3 times in a mechanical direction at 135°C by the use of a roll type longitudinal orientation machine.
The resulting mono-oriented film was oriented by 50% of the total transversal orientation at 145°C in the first orientation zone, and then, the resulting film was oriented to 3.3 times of the total transversal orientation at 155°C in the second orientation zone. Next, the resulting film was heated at 100°C for 2 seconds. Then, the resulting film was subjected to heat-set for 5 seconds at 200°C in the first heat-set zone and then the resulting film was subjected to heat-set for 15 seconds at 240°C in the second heat-set zone. Next, while the resulting film was loosened in the transversal direction by 5%, the film was chilled to room temperature gradually to obtain a biaxially-oriented film having thickness of 80µm.

(Film 2)

Polyester F was subjected to vacuum drying at 150°C for 8 hours. Thereafter, it was melted and extruded from a T die in a layer form at 300°C. It was statically brought into contact with a chilling drum at 40°C, chilled and solidified for obtaining an unoriented sheet film. This unoriented sheet film was oriented by 3.3 times in a mechanical direction at 130°C by the use of a roll type longitudinal orientation machine.
The resulting mono-oriented film was oriented by 50% of the total transversal orientation at 140°C in the first orientation zone, and then, the resulting film was oriented to 3.3 times of the total transversal orientation at 150°C in the second orientation zone. Next, the resulting film was heated at 100°C for 2 seconds. Then, the resulting film was subjected to heat fixing for 5 seconds at 200°C in the first heat fixing zone and then the resulting film was subjected to heat fixing for 15 seconds at 240°C in the second heat fixing zone. Next, while the resulting film was loosened in the transversal direction by 5%, the film was chilled to room temperature gradually to obtain a biaxially-oriented film having thickness of 80µm.

(Film 3)

Polyester A and B were subjected to vacuum drying at 150°C for 8 hours. Thereafter, by the use of 2 units of extruders, they were melted and extruded at 300°C. In a T die, they are jointed in a layer form. The resulting film was statically brought into contact with a chilling drum at 40°C chilled and solidified for obtaining a laminated unoriented sheet film having two layers structure. In this occasion, the amount of extrusion of each extruder was regulated so that the ratio of the thickness of each layer be 1:1. This unoriented sheet film was oriented by 3.3 times in a mechanical direction at 130°C by the use of a roll type longitudinal orientation machine.
The resulting mono-oriented film was oriented by 50% of the total transversal orientation at 145°C in the first orientation zone, and then, the resulting film was oriented to 3.3 times of the total transversal orientation at 155°C in the second orientation zone. Next, the resulting film was heated at 100°C for 2 seconds. Then, the resulting film was subjected to heat fixing for 5 seconds at 200°C in the first heat fixing zone and then the resulting film was subjected to heat fixing for 15 seconds at 240°C in the second heat fixing zone. Next, while the resulting film was loosened in the transversal direction by 5% in 30 seconds, the film was chilled to room temperature gradually to obtain a biaxially-oriented film having thickness of 80µm.

(Film 4)

Polyester C and D were subjected to vacuum drying at 150'C for 8 hours. Thereafter, by the use of 2 units of extruders, they were melted and extruded at 285°C. In a T die, they were jointed in a layer form. The resulting film was statically brought into contact with a chilling drum at 30°C, chilled and solidified for obtaining a laminated unoriented sheet film having two layers structure. In this occasion, the amount of extrusion of each extruder was regulated so that the ratio of the thickness of each layer be 1:1. This unoriented sheet film was oriented by 3.3 times in a mechanical direction at 130°C by the use of a roll type longitudinal orientation machine.
The resulting mono-oriented film was oriented by 50% of the total transversal orientation at 100°C in the first orientation zone, and then, the resulting film was oriented to 3.3 times of the total transversal orientation at 115°C in the second orientation zone. Next, the resulting film was heated at 70°C for 2 seconds. Then, the resulting film was subjected to heat fixing for 5 seconds at 150°C in the first heat fixing zone and then the resulting film was subjected to heat fixing for 15 seconds at 230°C in the second heat fixing zone. Next, while the resulting film was loosened in the transversal direction by 5% in 30 seconds, the film was chilled to room temperature gradually to obtain a biaxially-oriented film having thickness of 90µm.

(Film 5)

Polyester A and E were subjected to vacuum drying at 150°C for 8 hours. Thereafter, by the use of 2 units of extruders, they were melted and extruded at 300°C. In a T die, they were jointed in a layer form. The resulting film was statically brought into contact with a chilling drum at 50°C chilled and solidified for obtaining a laminated unoriented sheet film having three layers structure. In this occasion, the amount of extrusion of each extruder was regulated so that the ratio of the thickness of each layer be 1:1:3. This unoriented sheet film was oriented by 3.3 times in a mechanical direction at 135°C by the use of a roll type longitudinal orientation machine.
The resulting mono-oriented film was oriented by 50% of the total transversal orientation at 145°C in the first orientation zone, and then, the resulting film was oriented to 3.3 times of the total transversal orientation at 155°C in the second orientation zone. Next, the resulting film was heated at 100°C for 2 seconds. Then, the resulting film was subjected to heat fixing for 5 seconds at 200°C in the first heat fixing zone and then the resulting film was subjected to heat fixing for 15 seconds at 240°C in the second heat fixing zone. Next, while the resulting film was loosened in the transversal direction by 5% in 30 seconds, the film was chilled to room temperature gradually to obtain a biaxially-oriented film having thickness of 80µm.
The intrinsic viscosity and the glass transition temperature of each layer of the resulting biaxially-oriented film were measured. The intrinsic viscosity of polyester A of film 1 was 0.58, the glass transition temperature and melting point thereof were 123°C and 270°C, respectively. The intrinsic viscosity of polyester F of film 2 was 0.60, the glass transition temperature and melting point thereof were 105°C and 267°C, respectively. The intrinsic viscosity of polyester A of film 3 was 0.58, the glass transition temperature and melting point thereof were 123°C and 270°C, respectively. The intrinsic viscosity of polyester B of film 3 was 0.52, the glass transition temperature and melting point thereof were 125°C and 265°C, respectively. The intrinsic viscosity of polyester C of film 4 was 0.63, the glass transition temperature and melting point thereof were 76°C and 260°C, respectively. The intrinsic viscosity of polyester D of film 4 was 0.60, the glass transition temperature and melting point thereof were 85°C and 255°C, respectively. The intrinsic viscosity of polyester A of film 5 was 0.58, the glass transition temperature and melting point thereof were 123°C and 270°C, respectively. The intrinsic viscosity of polyester E of film 5 was 0.52, the glass transition temperature and melting point thereof were 100°C and 260°C, respectively. Incidentally, film 3 was curled to polyester A side. Film 4 was curled to polyester C side. Film 5 was curled to the thinner polyester E layer. Therefore, processing thereafter was conducted so that the concave surfaces was on a photographic light-sensitive layer side.
The film sample thus obtained was wound on a paper core having a diameter of 200 mm and subjected to humidity conditioning at 23°C and at 55%RH for periods as shown in Tables 4 through 7. Thereafter, the wound sample was re-wound on another paper core having a diameter of 200 mm. At this time the leading portion and trailing portion of the film sample had the same moisture content.
The rolled sample was packaged in two layers of 20 µm polyethylene film vapor deposited with aluminum. The packaged sample was processed to reduce curling degree as shown in Tables 4 through 7 and further kept at 23°C and at 55%RH for 48 hours.
The above obtained film was evaluated for the above described physical properties and the results are shown in Tables 4 through 7.
The subbing layers were coated according to the following procedures.
The film was subjected to corona discharge treatment on one side thereof. The following subbing solution A-1 was coated thereon at ordinary temperature and humidity using a roll fit coating pan and an air knife, and dried at 90°C for 30 minutes to obtain subbing layer A-1 having a dry thickness of 0.8 µm. The following subbing solution B-1 was coated on the other side in the same manner as above to obtain subbing layer B-1 having a dry thickness of 0.8 µm.

Latex comprising a copolymer of 30 wt% butyl acrylate, 20 wt% t-butyl acrylate, 25 wt% styrene, and 25 wt% 2-hydroxyethyl acrylate (30 wt% solid content)	270 g
Compound UL-1	0.6 g
Hexamethylene-1,6-bis(ethylene urea)	0.8 g
Water was added to	1,000 ml

Latex comprising a copolymer of 40 wt% butyl acrylate, 20 wt% styrene, and 40 wt% glycidyl acrylate (30 wt% solid content)	270 g
Compound UL-1	0.6 g
Hexamethylene-1,6-bis(ethylene urea)	0.8 g
Water was added to	1,000 ml

After subjecting subbing layers A-1 and B-1 to corona discharge treatment at 8 W/m²·min, subbing layer A-2 was formed on subbing layer A-1 by coating the following subbing solution A-2 to a dry coating thickness of 0.1 µm, and subbing layer B-2 was formed on subbing layer B-1 by coating the following subbing solution B-2 to a dry coating thickness of 0.8 µm.

Gelatin	10 g
Compound UL-1	0.2 g
Compound UL-2	0.2 g
Compound UL-3	0.1 g
Silica particles (average particle size:3 µm)	0.1 g
Water was added to	1,000 ml

Water-soluble conductive polymer UL-4	60 g
Latex comprising compound UL-5 (20% solid content)	80 g
Ammonium sulfate	0.5 g
Hardener UL-6	12 g
Polyethylene glycol (weight average molecular weight:600)	6 g
Water was added to	1,000 ml

The subbing layer B-2 of the above obtained film support was subjected to corona discharge treatment at 8 W/m²·min. and the following coating solution MC-1 was coated thereon to have a dry thickness of 1 µm.

(MC-1)

The following components were mixed in a dissolver and dispersed by a sand-mill to obtain a dispersion. The amount is in terms of parts by weight.

Nitrocellulose	70 parts
Lauric acid	1 part
Oleic acid	1 part
Butyl stearate	1 part
Cyclohexanone	75 parts
Methylethyl ketone	150 parts
Toluene	150 parts
Co covered γ-Fe₂O₃	5 parts

(Major axis:0.2 µm, minor axis:0.2 µm, Hc = 650 ersted)
Further, the following coating solution OC-1 was coated on the MC-1 layer to have a coating amount of 10 ml/m².

<OC-1>

Carnauba wax	1g
Toluene	700 ml
Methylethyl ketone	300 ml

The above obtained film was evaluated for coating failure or flatness. The results are shown in Tables 4 through 7.
The 35 × 150 mm film sample was subjected to humidity conditioning for 6 hours at 23°C and at relative humidity of 0, 20, 40 or 60%. Thereafter, each sample was wound around a core having a diameter of 89 mm and packaged in a 20 µm thick polyethylene film doubly. The packaged sample was further stored for 168 hours at 23°C and at 55%RH, and then was released from the core. Thirty minutes after the core release, the curling degree of the resulting sample was evaluated in terms of reciprocal (m^-1) of the radius of curvature.
The moisture content of the sample after the humidity conditioning and the curling degree were as follows:

Humidity condition (%RH) Moisture content of the sample (%) Curling degree (m^-1)

0 0 2

10 0.05 2

20 0.10 3

40 0.20 5

60 0.25 10
As is seen from the above, samples having a moisture content of not more than 0.2% exhibit reduced curling degree.
A 25-W/m²·min corona discharge was given to subbing layer A-2, and then, multilayered color photographic material was prepared by forming the following photographic layers in sequence. The amounts of the components in the following photographic layers are per square meter of the material, unless specifically stated. The amount of silver halide or colloidal silver is represented in terms of silver amount.

1st layer; antihalation layer HC
Black colloidal silver	0.15 g
UV absorbent UV-1	0.20 g
Colored cyan coupler CC-1	0.02 g
High boiling solvent Oil-1	0.20 g
High boiling solvent Oil-2	0.20 g
Gelatin	1.6 g
2nd layer; intermediate layer IL-1
Gelatin	1.3 g
3rd layer; low-speed red-sensitive emulsion layer R-L Silver iodobromide emulsion (average grain size: 0.3 µm, average iodide content:2.0 mol%)	0.4 g
Silver iodobromide emulsion (average grain size: 0.4 µm, average iodide content:8.0 mol%)	0.3 g
Sensitizing dye S-1	3.2 × 10^-4 (mol/mol of silver)
Sensitizing dye S-2	3.2 × 10^-4 (mol/mol of silver)
Sensitizing dye S-3	0.2 × 10^-4 (mol/mol of silver)
Cyan coupler C-1	0.50 g
Cyan coupler C-2	0.13 g
Colored cyan coupler CC-1	0.07 g
DIR compound D-1	0.006 g
DIR compound D-2	0.01 g
High boiling solvent Oil-1	0.55 g
Gelatin	1.0 g
4th layer; high-speed red-sensitive emulsion layer R-H Silver iodobromide emulsion (average grain size: 0.7 µm, average iodide content:7.5 mol%)	0.9 g
Sensitizing dye S-1	1.7 × 10^-4 (mol/mol of silver)
Sensitizing dye S-2	1.6 × 10^-4 (mol/mol of silver)
Sensitizing dye S-3	0.1 × 10^-4 (mol/mol of silver)
Cyan coupler C-2	0.23 g
Colored cyan coupler CC-1	0.03 g
DIR compound D-2	0.02 g
High boiling solvent Oil-1	0.25 g
Gelatin	1.0 g
5th layer; intermediate layer IL-2
Gelatin	0.8 g
6th layer; low-speed green-sensitive emulsion layer G-L Silver iodobromide emulsion (average grain size: 0.4 µm, average iodide content:8.0 mol%)	0.6 g
Silver iodobromide emulsion (average grain size: 0.3 µm, average iodide content:2.0 mol%)	0.2 g
Sensitizing dye S-4	6.7 × 10^-4 (mol/mol of silver)
Sensitizing dye S-5	0.8 × 10^-4 (mol/mol of silver)
Magenta coupler M-1	0.17 g
Magenta coupler M-2	0.43 g
Colored magenta coupler CM-1	0.10 g
DIR compound D-3	0.02 g
High boiling solvent Oil-2	0.7 g
Gelatin	1.0 g
7th layer; high-speed green-sensitive layer G-H
Silver iodobromide emulsion (average grain size: 0.7 µm, average iodide content:7.5 mol%)	0.9 g
Sensitizing dye S-6	1.1 × 10^-4 (mol/mol of silver)
Sensitizing dye S-7 x	2.0 × 10^-4 (mol/mol of silver)
Sensitizing dye S-8	0.3 × 10^-4 (mol/mol of silver)
Magenta coupler M-1	0.30 g
Magenta coupler M-2	0.13 g
Colored magenta coupler CM-1	0.04 g
DIR compound D-3	0.004 g
High boiling solvent Oil-2	0.35 g
Gelatin	1.0 g
8th layer; yellow filter layer (YC)
Yellow colloidal silver	0.1 g
Additive HS-1	0.07 g
Additive HS-2	0.07 g
Additive SC-1	0.12 g
High boiling solvent Oil-2	0.15 g
Gelatin	1.0 g
9th layer; low-speed blue-sensitive emulsion layer B-L
Silver iodobromide emulsion (average grain size: 0.3 µm, average iodide content:2.0 mol%)	0.25 g
Silver iodobromide emulsion (average grain size: 0.4 µm, average iodide content:8.0 mol%)	0.25 g
Sensitizing dye S-9	5.8 × 10^-4 (mol/mol of silver)
Yellow coupler Y-1	0.6 g
Yellow coupler Y-2	0.32 g
DIR compound D-1	0.003 g
DIR compound D-2	0.006 g
High boiling solvent Oil-2	0.18 g
Gelatin	1.3 g
10th layer; high-speed blue-sensitive emulsion layer B-H
Silver iodobromide emulsion (average grain size: 0.8 µm, average iodide content:8.5 mol%)	0.5 g
Sensitizing dye S-10	3 × 10^-4 (mol/mol of silver)
Sensitizing dye S-11	1.2 × 10^-4 (mol/mol of silver)
Yellow coupler Y-1	0.18 g
Yellow coupler Y-2	0.10 g
High boiling solvent Oil-2	0.05 g
Gelatin	1.0 g
11th layer; 1st protective layer PRO-1
Silver iodide (average grain size:0.08 µm)	0.3 g
UV absorbent UV-1	0.07 g
UV absorbent UV-2	0.10 g
Additive HS-1	0.2 g
Additive HS-2	0.1 g
High boiling solvent Oil-1	0.07 g
High boiling solvent Oil-3	0.07 g
Gelatin	0.8 g
12th layer; 2nd protective layer PRO-2
Compound A	0.04 g
Compound B	0.004 g
Polymethyl methacrylate (average particle size:3 µm)	0.02 g
Gelatin	0.7 g

-Preparation of Silver Iodobromide Emulsion-

The silver iodobromide emulsion used in the 10th layer was prepared by the following method.
Using monodispersed silver iodobromide grains having an average grain size of 0.33 µm and a silver iodide content of 2 mol% as seed grains, the silver iodobromide emulsion was prepared by means of a double jet method.
While stirring the following solution G-1 under conditions of 70°C, pAg 7.8 and pH 7.0, 0.34 mol of the seed emulsion was added thereto.

(Formation of Inner High Iodide Content Phase-Core Phase)

Then, the following solutions H-1 and S-1 were added, while keeping the flow ratio at 1:1, in 86 minutes at an accelerated flow rate (the final flow rate was 3.6 times the initial flow rate).

(Formation of Outer Low Iodide Content Phase-Shell Phase)

Subsequently, the following solutions H-2 and S-2 were added at a flow ratio of 1:1 in 65 minutes, under conditions of pAg 10.1 and pH 6.0, while accelerating the flow rate so as to make the final flow rate 5.2 times the initial flow rate.
During grain formation, the pAg and pH were controlled with an aqueous solution of potassium bromide and an aqueous solution of 56% acetic acid. The resulting silver halide grains were desalted according to the usual flocculation method and redispersed with the addition of gelatin to give an emulsion, which was then adjusted to pH 5.8 and pAg 8.06 at 40°C.
The emulsion thus obtained was a monodispersed emulsion comprising octahedral silver iodobromide grains having an average grain size of 0.80 µm, a grain size distribution extent of 12.4% and a silver iodide content of 8.5 mol%.

Osein gelatin	100.0 g
10 weight% ethanol solution of the following Compound-I	25.0 ml
28% aqueous ammonia	440.0 ml
56% aqueous acetic acid solution	660.0 ml
Water was added to (Compound-I : Sodium polyisopropyleneoxypolyethyleneoxy disuccinate)	5,000.0 ml

Osein gelatin	82.4 g
Potassium bromide	151.6 g
Potassium iodide	90.6 g
Water was added to	1,030.5 ml

Silver nitrate	309.2 g
28% Aqueous ammonia	equivalent
Water was added to	1,030.5 ml

Osein gelatin	302.1 g
Potassium bromide	770.0 g
Potassium iodide	33.2 g
Water was added to	3,776.8 ml

Solution S-2

Silver nitrate	1,133.0 g
28% Aqueous ammonia	equivalent
Water was added to	3,776.8 ml

The silver iodobromide emulsions used in the emulsion layers other than the 10th layer were prepared in the same way so as to give different average grain sizes and silver iodide contents, by varying the average grain size of seed grains, temperature, pAg, pH, flow rate, addition time and halide composition.
Each of these emulsions, which were monodispersed emulsions comprised core/shell type grains having a distribution extent not more than 20%, was optimally chemically ripened in the presence of sodium thiosulfate, chloroauric acid and ammonium thiocyanate. Then, sensitizing dyes, 4-hydroxy-6-methyl-1,3,3a,7-tetrazaindene and 1-phenyl-5-mercaptotetrazole were added thereto.
In addition to the above components, photographic light-sensitive materials 1 to 5 contained compounds Su-1 and Su-2, a viscosity regulator, hardeners H-1 and H-2, stabilizer ST-1, antifoggants AF-1 and AF-2 (weight average molecular weights were 10,000 and 1,100,000, respectively), dyes AI-1 and AI-2, and compound DI-1 (9.4 mg/m²).
The chemical structures of the compounds used in the above multilayered light-sensitive materials were as follows:
The thus obtained light sensitive material was cut to have a size of 35 × 1200 mm, and perforated according to the description of JIS 7519-1982. The resulting material was evaluated for remaining curl, transportability through a pre-splicer and handling operability. The results are shown in Tables 4 through 7.

In Tables 4 through 7, items, humidity conditioning time, moisture content, heat treatment, density, haze, curling degree in transversal direction, modulus of elasticity, rupture strength, coefficient of thermal shrinkage and coefficient of hygroscopic expansion relate to the film, items, coating fault and flatness to a film having a subbing layer, and items, remaining curl, pre-splicer transportability and handling operability to a photographic light sensitive material.

Photographic light sensitive material No.	1	2	3	4	5
Film No.	1	1	1	1	1
Humidity conditioning	hours	0	3	6	24	72
Moisture content	%	0	0.05	0.1	0.2	0.25
Heat treatment time	hours	24	24	24	24	24
Heat treatment temperature	°C	60	60	60	60	60
Density	g/cm³	1.366	1.366	1.366	1.366	1.366
Haze	%	0.5	0.5	0.5	0.5	0.5
Curling degree in the transversal direction	m^-1	0	0	0	0	0
Modulus of elasticity	MD	kg/mm²	680	680	680	680	680
TD		720	720	720	720	720
Rupture strength	MD	kg/mm²	25	25	25	25	25
TD		27	27	27	27	27
Coefficient of thermal shrinkage	MD	%	0.5	0.5	0.4	0.4	0.4
TD		0.0	0.0	0.0	0.0	0.0
Coefficient of hygroscopic expansion	MD	-/%RH	15×10^-6	15×10^-6	13×10^-6	10×10^-6	10×10^-6
TD		12×10^-6	12×10^-6	10×10^-6	8×10^-6	8×10^-6
Coating fault	Rank	○	○	○	o ○	o ○
Flatness	Rank	○	○	○	o ○	o ○
Remaining curl	m^-1	130	115	105	90	80
Pre-splicer transportability	Rank	×	×	○	o ○	o ○
Handling operability	Rank	×	×	○	o ○	o ○
Remarks		Comp.	Comp.	Inv.	Inv.	Inv.
Comp.: Comparative Inv.: Invention MD : machine direction TD : transversal direction

Photographic light sensitive material No.	6	7	8	9
Film No.	1	1	1	1
Humidity conditioning	hours	168	72	72	72
Moisture content	%	0.3	0.25	0.25	0.25
Heat treatment time	hours	24	168	720	6
Heat treatment temperature	°C	60	40	20	80
Density	g/cm³	1.366	1.366	1.366	1.366
Haze	%	0.5	0.5	0.5	0.5
Curling degree in the transversal direction	m^-1	0	0	0	0
Modulus of elasticity	MD	kg/mm²	680	680	680	680
TD		720	720	720	720
Rupture strength	MD	kg/mm²	25	25	25	25
TD		27	27	27	27
Coefficient of thermal shrinkage	MD	%	0.4	0.4	0.4	0.4
TD		0.0	0.0	0.0	0.0
Coefficient of hygroscopic expansion	MD	-/%RH	10×10^-6	10×10^-6	10×10^-6	10×10^-6
TD		8×10^-6	8×10^-6	8×10^-6	8×10^-6
Coating fault	Rank	o ○	o ○	o ○	○
Flatness	Rank	o ○	o ○	o ○	○
Remaining curl	m^-1	70	70	70	100
Pre-splicer transportability	Rank	o ○	o ○	o ○	○
Handling operability	Rank	o ○	o ○	o ○	○
Remarks		Inv.	Inv.	Inv.	Inv.
Comp.: Comparative Inv. : Invention MD : machine direction TD : transversal direction

Photographic light sensitive material No.	11	12	13	14	15
Film No.	1	2	3	4	5
Humidity conditioning	hours	0	72	72	72	72
Moisture content	%	0	0.3	0.5	0.6	1.5
Heat treatment time	hours	24	48	48	48	48
Heat treatment temperature	°C	110	60	60	40	60
Density	g/cm³	1.366	1.360	1.355	1.390	1.360
Haze	%	0.5	0.7	0.7	0.4	1.0
Curling degree in the transversal direction	m^-1	0	0	20	25	40
Modulus of elasticity	MD	kg/mm²	680	640	680	500	650
TD		720	680	720	550	700
Rupture strength	MD	kg/mm²	25	22	25	19	20
TD		27	25	26	20	25
Coefficient of thermal shrinkage	MD	%	0.4	0.7	0.6	0.8	1.0
TD		0.0	0.0	0.0	0.0	0.0
Coefficient of hygroscopic expansion	MD	-/%RH	11×10^-6	11×10^-6	12×10^-6	12×10^-6	18×10^-6
TD		9×10^-6	9×10^-6	10×10^-6	11×10^-6	14×10^-6
Coating fault	Rank	×	○	o ○	○	o ○
Flatness	Rank	×	○	o ○	○	o ○
Remaining curl	m^-1	70	100	40	100	90
Pre-splicer transportability	Rank	o ○	○	o ○	○	o ○
Handling operability	Rank	o ○	○	o ○	○	o ○
Remarks		Comp.	Inv.	Inv.	Inv.	Inv.
Comp.: Comparative Inv.: Invention MD : machine direction TD : transversal direction

Photographic light sensitive material No.	16
Film No.	5
Humidity conditioning	hours	168
Moisture content	%	1.7
Heat treatment time	hours	48
Heat treatment temperature	°C	60
Density	g/cm³	1.360
Haze	%	1.0
Curling degree in the transversal direction	m^-1	40
Modulus of elasticity	MD	kg/mm²	650
TD		700
Rupture strength	MD	kg/mm²	20
TD		25
Coefficient of thermal shrinkage	MD	%	1.0
TD		0.0
Coefficient of hygroscopic expansion	MD	-/%RH	17×10^-6
TD		13×10^-6
Coating fault	Rank	×
Flatness	Rank	×
Pre-splicer transportability	Rank	o ○
Handling operability	Rank	o ○
Remarks		Comp.
Comp.: Comparative Inv.: Invention MD : machine direction TD : transversal direction

As is seen from Tables 4 to 7, samples prepared according to the invention, comprising a polyester film support heat treated under an appropriate moisture content are reduced in remaining curl, excellent in pre-splicer transportability and handling operability as compared with comparative samples. Further, it has been proved that the samples subjected to high temperature conditioning has many coating faults and poor flatness, although reduced in remaining curl.

Example 2

In the following example, glass transition temperature and melting point, film haze, moisture content, intrinsic viscosity, coefficient of elasticity and rupture strength, coefficient of thermal shrinkage, curling degree in transversal direction, remaining curl value and coating fault after coating a subbing layer were measured in the same manner as in Example 1. Remaining curl after processing was measured as follows.

Remaining curl after processing

A light sensitive material of 12 cm x 35 mm was wound on a roll core having 10 mm of diameter in such a manner that photographic constituting layers side was wound insidely. The resulting material was left for 3 days at 55°C and 20%RH to give curling. Thereafter, the material was released from the roll core, and then, immersed in pure water at 38°C for 15 minutes. Next, load of 50 g was applied thereto and dried for 3 minutes with a heat air drier. Then, the load was removed. The resulting sample was hang vertically, and distance of both ends of the sample was measured so that the ratio of the distance of the initial length of 12 cm was calculated. Evaluation was conducted by the following criteria.
o ○: 70% or more
○: 50% or more to less than 70%
×: Less than 50%
Incidentally, ○ or higher refers to practically non-problematic level.
To both ends of each of biaxially-oriented films 1 to 5 obtained in Example 1, an embossing ring heated to 250°C was applied with pressure. While adjusting the pressure so that the height becomes 30 µm, embossing was carried out in an entire mechanical direction.
Film 3 showed convex curl on polyester A side. Film 4 showed convex curl on polyester C side and film 5 showed convex curl on the thinner layer composed of polyester E. Accordingly, the succeeding procedures were carried out so that the convex side is the photographic light-sensitive layer side.

In the same manner as in Example 1 subbing layers A-1, A-2, B-1 and B-2 were coated on the films above obtained.
The thus obtained film sample of 500 m was wound around a paper core having a diameter of 200 mm. Sample Nos. 1 to 15 were subjected to humidity conditioning at 23°C and at 55%RH for a period shown in Table 8, and sample No. 16 was subjected to humidity conditioning at 23°C and at 80%RH for a period shown in Table 8. Thereafter, the wounded samples were rolled around another paper core having a diameter of 250 mm. At this time the moisture content of the leading portion and trailing portion of the film sample was measured.
The rolled sample was doubly packaged in a 20 µm thick polyethylene film, heat treated as shown in Table 8, and further kept at 23°C and at 55%RH for 48 hours.
The resulting sample was evaluated for coefficient of thermal shrinkage and coefficient of hygroscopic expansion.
The subbing layer A-2 of the above film sample was subjected to corona discharge treatment at 8 W/m²·min., and photographic layers were provided thereon in the same manner as in Example 1. Thus, a color photographic light sensitive material was obtained.
Thus obtained light sensitive material was perforated according to the description of JIS 7519-1982. The coating fault or flatness of portions adjacent to the core were checked. Further, the remaining curl after processing was evaluated. The physical properties of the film and the test results are shown in Table 8.
As is seen from Table 5, samples prepared according to the invention comprising a polyester film support which is heat-treated under an appropriate moisture content are reduced in remaining curl after processing as compared with comparative samples. The samples prepared according to the invention are reduced in coefficient of hygroscopic expansion, and have excellent flatness and less coating fault even when heat treated in the form of rolled film, since low temperature can be applied. The high temperature application enables shortening of the time.

Claims

A process for preparing a support for a light sensitive material comprising the steps of:

subjecting a support comprising a biaxially oriented polyester film to humidity conditioning to have a moisture content of from 0.1 to 1.5% by weight; and

heat-treating the thus conditioned support at a temperature between 15°C and less than (Tg of the polyester film -5)°C.
The process of claim 1, wherein the polyester film subjected to humidity conditioning to have a moisture content of from 0.1 to 1.5% by weight is heat treated at a temperature of from 15°C to less than (Tg - 30)°C.
The process of claim 1 or 2, wherein the polyester film comprises an ethyleneterephthalate or ethylene 2,6-naphthalate unit.
The process of claim 3, wherein the polyester film comprises the ethyleneterephthalate or ethylene 2,6-naphthalate unit in an amount of 70% by weight or more.
The process of claim 3, wherein the polyester film comprises an ethylene 2,6-naphthalate unit.
The process of any preceding claim, wherein the polyester film comprises two or more layers and at least one of the layers comprises a polyester comprising a dicarboxylic acid unit having a metal sulfonate group as a copolymerization unit.
The process of any preceding claim, wherein the heating time is 0.1 hours or more.
The process of any preceding claim, which further comprises providing a subbing layer.
The process of any preceding claim, comprising the step of winding the support on the core having a diameter of not less than 200 mm before the heat-treating of the support.
A process for preparing a light sensitive material comprising a support and a photosensitive layer, comprising the steps of:

subjecting a support comprising a biaxially oriented polyester film to humidity conditioning to have from a moisture content of from 0.1 to 1.5% by weight;

preserving the support at a temperature between 15°C and less than (Tg of the polyester film -5)°C; and

coating the thus obtained support with at least one light-sensitive layer.
The process of claim 10, comprising the steps of:

coating a subbing layer on the support; and

coating with the light-sensitive layer after the preserving step.