JPH10260500A - Film base for photographic film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the film base for the photographic film superior in mechanical characteristics and curling characteristics and transparency and the like. SOLUTION: This film base is a laminate of a first layer made of polyethylene-2,6-naphthalenedicarboxylate and a second layer made of a copolymer polyester composed of 2,6-naphthalenedicarboxylic acid as an acid component and ethylene glycol bis 4-(2-hydroxyethoxy)phenyl}sulfone as diol components and/or a mixture of this copolymer and the polyethylene-2,6- naphthalenedicarboxylate, and this base has a heat absorption peak in the temperature range of 120-160 deg.C, and a ratio of the first layer thickness to the second layer thickness is 1/4-4/1, and the sum of both layers is 40-120 μm, and its haze value is <=2.0%, and a curling degree in the lateral direction is 5-30 m<-1> and that in the longitudinal direction is <40 m<-1> .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a base film for a photographic film, and more particularly to a base film for a photographic film, which has excellent mechanical properties, delamination resistance (delamination) resistance, and transparency, and is provided with a photosensitive agent layer. The present invention relates to a photographic film base film having excellent film processing characteristics.

[0002]

2. Description of the Related Art Photo films are used as roll films such as negative films which are mounted on a general camera and used for photographing, X-ray films, plate making films, and the like.
Some are used as sheet films such as cut films.

[0003] A triacetyl cellulose (hereinafter sometimes abbreviated as "TAC") film is mainly used for the base film of the roll film, and a biaxially stretched polyethylene terephthalate film is mainly used for the base film of the sheet film. Used.

A TAC film has a low optical anisotropy and a high transparency, and furthermore, as a plastic film, has a relatively high water absorption. Therefore, the TAC film has a curl caused by being aged while being wound as a roll film. It has excellent properties to be eliminated due to rearrangement of molecular chains due to water absorption during development processing.

[0005] However, with the progress of downsizing of the photographing apparatus and the like, it is necessary to reduce the size of the patrone for storing the photographic film, and the thickness of the photographic film base film used for this purpose is also reduced. In addition, it has been required that mechanical strength and dimensional stability have sufficient performance even if the thickness is small. However, when the thickness of the TAC film is reduced, the mechanical strength is insufficient, and such a requirement cannot be satisfied.

By the way, polyethylene terephthalate films are used in many applications because they have excellent mechanical properties, transparency, dimensional stability, heat resistance and chemical resistance.

However, this polyethylene terephthalate film has a curl in the longitudinal direction (hereinafter simply referred to as a "curl habit") when it is rolled into a photographic film and held for a long time.
) Is insufficient in the property (hereinafter, sometimes referred to as "curl recovery property") after the development processing, and the curl remains strongly in the film after development.

For this reason, when the developed film is further used in a process of forming an image on a photographic printing paper, problems such as scratches and defocusing occur, and the developed film is used as a base film of a roll film. Is difficult.

Various proposals have been made to use a polyethylene-2,6-naphthalenedicarboxylate film as a roll film as a polyester film which can improve mechanical properties, dimensional stability and heat resistance more than a polyethylene terephthalate film. In the case of a conventional photographic film using a polyethylene-2,6-naphthalenedicarboxylate film as a base film, when the photosensitive layer is coated, the shrinkage during drying of the photosensitive layer is larger than the shrinkage of the base film. After the film is set, the film curls in the width direction (in a state of being concave on the photosensitive agent layer side), and there is a problem in processing characteristics of the film.

As a countermeasure against this curling, a first layer made of polyethylene-2,6-naphthalenedicarboxylate and polyethylene-2,6-naphthalenedicarboxylate copolymerized with various dibasic acids and / or glycols are used. The first in the laminated film with the second layer
A method has been studied in which a curl in the width direction due to a difference in contraction stress between the layer and the second layer is developed to cancel the curl in the width direction due to shrinkage of the photosensitive agent layer during drying.

[0011]

SUMMARY OF THE INVENTION It is an object of the present invention to overcome the above-mentioned drawbacks of the film, to provide excellent mechanical properties, transparency and curl properties, and to provide a film width after a photosensitive agent layer is applied. An object of the present invention is to provide a photographic base film which suppresses curling in the direction and has excellent processing characteristics.

[0012]

The object of the present invention is to provide, according to the present invention, (a) a first layer (a1) comprising polyethylene-2,6-naphthalenedicarboxylate;
A copolyester containing naphthalenedicarboxylic acid as an acid component and ethylene glycol and bis (4- (2-hydroxyethoxy) phenyl) sulfone as a diol component, and / or the copolymer polyester and polyethylene-2,
A laminated film comprising a second layer (a2) comprising a mixture with 6-naphthalenedicarboxylate, wherein (b) 1
Shows an endothermic peak of 0.3 mJ / mg or more in a temperature range of 20 to 160 ° C., (c) a ratio of the thickness of the first layer to the thickness of the second layer is ４ to 4/1, and (d) The sum of the thickness of the first layer and the thickness of the second layer is 40 to 120 μm,
(E) the haze value of the laminated film is 2.0% or less;
(F) The degree of curl in the width direction of the laminated film is 5 to 30 m ^-1.
And (g) a curl degree of curl in the longitudinal direction of the laminated film of less than 40 m ^-1 can be achieved by a base film for a photographic film. Hereinafter, the present invention will be described in detail.

[First Layer] In the present invention, the polyethylene-2,6-naphthalenedicarboxylate used in the first layer contains ethylene-2,6-naphthalenedicarboxylate in an amount of 97 mol% or more, preferably 98 mol%. It is a polymer having the above components, and may be a homopolymer, a copolymer or a mixture thereof. As a monomer unit component constituting these polymers, one kind other than 2,6-naphthalenedicarboxylic acid and ethylene glycol is used. The above components (hereinafter sometimes referred to as “third component”) are 3 in total.
It can be contained in an amount of less than 2 mol%, preferably less than 2 mol%, particularly preferably less than 1 mol%. 3 mol%
Exceeding the above is not preferable because the excellent mechanical properties of polyethylene-2,6-naphthalenedicarboxylate are not exhibited.

The following components can be exemplified as the third component. Examples of the acid component include oxalic acid, adipic acid, phthalic acid, sebacic acid, dodecanedicarboxylic acid, succinic acid, isophthalic acid, 5-sodium sulfoisophthalic acid, terephthalic acid, 2-potassium sulfoterephthalic acid, and 2,7-naphthalenedicarboxylic acid Dicarboxylic acids such as acid, 1,4-cyclohexanedicarboxylic acid, 4,4′-diphenyldicarboxylic acid, phenylindanedicarboxylic acid and diphenyletherdicarboxylic acid; and oxycarboxylic acids such as p-oxyethoxybenzoic acid.

As the diol component, for example, propylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6- Hexanediol, 1,2-cyclohexanedimethanol,
1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, p-xylylene glycol, ethylene oxide adduct of bisphenol A, diethylene glycol, triethylene glycol, polyethylene oxide glycol, polytetramethylene oxide glycol, neopentyl glycol, etc. Such dihydric alcohols are exemplified.

The polyethylene-2,6-naphthalenedicarboxylate has a terminal hydroxyl group and / or a carboxyl group partially or entirely blocked by a monofunctional compound such as benzoic acid or methoxypolyalkylene glycol. Alternatively, it may be modified with a very small amount of an ester-forming compound having three or more functions such as glycerin and pentaerythritol within a range where a substantially linear polymer can be obtained.

The polymer of the first layer may contain bis (4- (2-hydroxyethoxy) phenyl) sulfone as a third component, but the content of bis (4
It should be lower than the content of-(2-hydroxyethoxy) phenyl) sulfone, the lower the better, the more preferable it is less than 0.2 mol%.

[Second Layer] The polymer used for the second layer is
A copolymerized polyester containing 2,6-naphthalenedicarboxylic acid as an acid component and ethylene glycol and bis (4- (2-hydroxyethoxy) phenyl) sulfone as a diol component and / or a copolymerized polyester and polyethylene-2,6- It is a mixture with naphthalenedicarboxylate.

The polymer used for the second layer is bis (4- (2-hydroxyethoxy)) as a component of the polymer.
The phenyl) sulfone component is contained in an amount of 0.2 to 10 mol% based on the 2,6-naphthalenedicarboic acid component. The bis (4- (2-hydroxyethoxy) phenyl) sulfone component is present as a copolymer component and / or as a monomer component of the polymer constituting the polymer mixture, preferably as a copolymer component.

If the amount is less than 0.2 mol%, the effect of canceling the curl in the width direction of the film by the photosensitive agent layer becomes insufficient, and if it exceeds 10 mol%, the mechanical strength of the base film becomes insufficient, or The coloring of the film becomes remarkable. If the coloring of the base film is remarkable, for example, when a dye is added to the base film to impart light-piping prevention properties, the optical density should be increased more than necessary to make the optical density uniform over the entire visible light region. Inevitably, transparency is impaired.

It is preferred that the first layer does not contain a bis (4- (2-hydroxyethoxy) phenyl) sulfone component. However, when the component is present in the first layer, the bis (4- (2- (2-hydroxyethoxy) phenyl) sulfone component is present. The proportion of the hydroxyethoxy) phenyl) sulfone component in the entire layer is higher in the second layer than in the first layer. The bis (4- (2
The first of the -hydroxyethoxy) phenyl) sulfone components
Assuming that the existing ratio of the layer to the total amount of the polymer is S ₁ mol%, the existing ratio of the same component in the second layer to the total amount of the polymer in the second layer is (S ₁ +0.2) to (S ₁ +10) mol%. .

The bis (4- (2-hydroxyethoxy) phenyl) sulfone component accounts for 0.2 to 10 mol% of the 2,6-naphthalenedicarboxylic acid component in the second layer formed on the film. It is also possible to use a polymer prepared by copolymerization so as to have this ratio, and to use a prepolymerized master polymer having a high bis (4- (2-hydroxyethoxy) phenyl) sulfone component concentration. You may use what was diluted with polyethylene-2,6-naphthalenedicarboxylate polymer and adjusted to such a concentration.

The reason is that when the chips are melt-extruded, a transesterification reaction occurs, and bis (4-
This is because the (2-hydroxyethoxy) phenyl) sulfone component is uniformly dispersed in the polyethylene-2,6-naphthalenedicarboxylate polymer.

In carrying out this transesterification reaction, the concentration of the bis (4- (2-hydroxyethoxy) phenyl) sulfone component in the master polymer is preferably 0.2 to 2,6-naphthalenedicarboxic acid component. ~
It is 50 mol%, more preferably 0.2 to 20 mol%. Within this range, the ester re-exchange reaction proceeds efficiently.

[Endothermic Energy] The base film for a photographic film of the present invention has an endothermic peak in the range of 120 to 160 ° C., preferably 130 to 150 ° C. when the film is thermally analyzed by a differential scanning calorimeter (DSC). (Abnormal specific heat) is observed.

This endothermic peak is different from the peak indicating the heat of crystal fusion. The endothermic energy representing the size of the endothermic peak is 0.3 mJ / mg or more, preferably 0.5 mJ / mg or more. A film having an endothermic peak temperature and an endothermic energy not in the above-mentioned ranges is inferior in difficulty in winding.

[Glass Transition Point] The copolymerized polyester constituting the second layer of the present invention preferably has a glass transition point (glass transition temperature) of less than 125 ° C. as measured by a differential scanning calorimeter (DSC). It is a polymerized polyester. When the glass transition point is less than 125 ° C., a film having excellent strength is obtained.

[Thickness of first layer / thickness of second layer] The laminated base film of the present invention has a ratio of the thickness of the first layer to the thickness of the second layer in the range of 1/4 to 4/1. Yes, and particularly preferably 1/3 to 3/1. If this ratio is smaller than 1/4, the curl recovery property and mechanical strength will be poor.
If this ratio is larger than 4/1, the effect of canceling the curl due to the photosensitive agent layer is insufficient.

[Base Film Thickness] The thickness of the base film for a photographic film of the present invention is such that the total thickness of the first layer and the second layer is in the range of 40 to 120 μm.
Preferably it is 50 to 100 μm. This thickness is 40μ
If it is less than m, the mechanical strength is insufficient, and if it exceeds 120 μm, the thinning of the film becomes meaningless.

[Haze value] The haze value of the base film for a photographic film of the present invention is 2.0% or less, preferably 1.5% or less. This haze is 2.
If it is larger than 0%, the transparency of the film is undesirably reduced.

[Additives] The polyethylene-2,6-naphthalenedicarboxylate and / or copolymerized polyester used in the present invention may contain additives such as stabilizers, lubricants, etc.
It may contain an ultraviolet absorber, a colorant, a flame retardant and the like.

The film of the present invention may contain a dye in the first layer and / or the second layer of the base film in order to impart light piping prevention. As a dye, heat resistance, compatibility and sublimation resistance are simultaneously satisfied,
In addition, those which are inert to silver halide emulsions and do not adversely affect photographic performance such as sensitivity and gamma are preferred.

Examples of such a dye include a red dye (having a maximum absorption wavelength in the range of 500 to 600 nm), a green dye (having a maximum absorption wavelength in the range of 600 to 700 nm), and a blue dye (having a maximum absorption wavelength of 600 to 600 nm). 680 nm). More preferably, a mixture of a red dye and a green dye in an appropriate ratio, a mixture of a red dye and a blue dye in an appropriate ratio, and the like are preferable.

The mixing ratio of the dye varies depending on the dye to be used.
Is preferable since transparency and light piping properties are improved.

The above-mentioned red dye, green dye and blue dye are preferably selected from, for example, anthraquinone dyes, triphenylmethane dyes, nitro dyes, stilbene dyes, indigoid dyes, thiazine dyes and azo dyes.

At that time, the colored base film preferably has a uniform optical density over the entire visible light region. That is, the optical density of the laminated film after dyeing measured with an optical densitometer manufactured by X-Rite Co.
50 or more, M for 0.050 or more, and Y for 0.050-0.
065, and the mutual relationship between C, M and Y is 0.
It is preferable that 030>CM> 0 and 0.030>MY> 0.

A colored base film that satisfies the above conditions for the optical density after coloring can be obtained by coloring the base film of the present invention by incorporating the above dye.

When the optical densities are smaller than the above lower limits, light incident from the film edge easily passes through the inside of the film, and the effect of preventing the light piping phenomenon cannot be obtained. Further, when each optical density is larger than the above upper limit, although the original purpose of imparting anti-piping properties is achieved, the optical density is unnecessarily high and the light transmittance is low, that is, unnecessarily. It becomes a dark base film, which is not preferable as a photographic film base film. Further, when the optical densities after coloring do not satisfy the above-mentioned relationship, the uniformity of the optical densities over the entire visible light region is poor, which is not preferable as a base film for a photographic film.

In the first place, the base film of the present invention containing polyethylene-2,6-naphthalenedicarboxylate as a substantial material is a film having a stronger yellow tint than a conventional TAC film or polyethylene terephthalate film. In dyeing for imparting anti-light-piping properties, it is desirable to color so as to achieve a uniform optical density over the entire visible light region, and for that purpose, a red dye, a green dye, and a blue dye are mixed at an appropriate ratio. It is preferable to dye using the compounded product.

The base film for a photographic film of the present invention can contain a small amount of inert fine particles in order to impart lubricity to the film.

Examples of such inert fine particles include inorganic particles such as spherical silica particles, calcium carbonate particles, alumina particles, zeolite particles, and kaolin particles, and organic particles such as silicon resin particles and crosslinked polystyrene particles. The inorganic particles are preferably synthetic products rather than natural products for reasons such as uniform particle size, and inorganic particles of any crystal form can be used.

The above-mentioned inert fine particles have an average particle size of 0.05.
It is preferably in the range of 1.5 μm. In particular, when the average particle size of the inert fine particles is smaller than 0.05 μm, the effect of improving the film's slipperiness, abrasion resistance or winding property is small, and when the average particle size is larger than 1.5 μm, the film becomes transparent. It is not preferable because the property is lowered. The content of inert particles is preferably from 0.001 to 0.2% by weight.

When the inert particles are inorganic particles, 0.001
It is preferably from 0.01 to 0.01% by weight, more preferably from 0.02 to 0.05% by weight.

When the inert fine particles are silicon resin particles, the content is preferably 0.001 to 0.1% by weight, more preferably 0.001 to 0.1% by weight.
It is preferably from 001 to 0.02% by weight, particularly preferably from 0.001 to 0.01% by weight.

When the inert fine particles are crosslinked polystyrene particles, the content is preferably 0.001 to 0.05% by weight. If the amount of the inert fine particles is less than the above amount, the film has insufficient slipperiness, while if it exceeds the above amount, the film haze increases, and the transparency becomes insufficient.
Not preferred.

The addition time of the inert fine particles is not particularly limited as long as it is a stage before the polyethylene-2,6-naphthalenedicarboxylate and / or the copolymerized polyester is formed into a film. And may be added during film formation.

The curl degree in the width direction of the photographic film base film of the present invention has a curl degree in the width direction of 5 to 30 m ^-1 with the second layer inside. That is,
The laminated base film of the present invention exhibits the property of bending in the width direction with the second layer inside (the second layer side curls concavely), and the degree of curl in the width direction is in the range of 5 to 30 m ^-1. It is. A photosensitive agent layer is applied to the first layer side of the laminated film of the present invention having such a curl degree. Curling in the width direction (curl by the photosensitive agent layer) due to drying shrinkage of the photosensitive agent layer causes the curl of the present invention. A photographic film with less curl, which is canceled by the curl in the width direction with two layers inside, can be obtained.

[ANSI Curl Value] The base film for a photographic film of the present invention has a property that a curl is hard to be formed, that is, a curl resistance. For example, the curl resistance at 80 ° C. is preferably an ANSI curl value of 40.
[M ^-1 ] or less. This 80 ° C. is an approximate value of the maximum temperature to which the photographic film can be usually exposed in daily life. If the ANSI curl value is larger than 40 [m ^-1 ], it becomes difficult to handle in the photographic processing step, which is not preferable.

Conventionally, the evaluation of the curl property of a photographic film is as follows.
It depends on the extent to which curling curls are eliminated through the usual photographic film development or drying process. On the other hand, the base film for a photographic film of the present invention is hardly curled, that is, excellent in curl resistance.

The above-mentioned hard winding property can be imparted, for example, by subjecting a roll film to a heat treatment at a temperature of (Tg-40) ° C. to Tg. The heat treatment time is preferably 0.1 to 1500 hours in terms of production efficiency. Heat treatment time (Tg
If the temperature is lower than −40) ° C., a very long time is required for the heat treatment, and the production efficiency is deteriorated. On the other hand, when the heat treatment temperature exceeds Tg, the hard-to-wind property is inferior and the hard-to-wind property tends to be formed.

[Young's Modulus] The base film for a photographic film of the present invention has a Young's modulus of 750 kg / mm ² or less, especially 700 kg / mm ² in two directions perpendicular to each other, for example, a vertical direction and a horizontal direction.
mm ² or less. Young's modulus is 750k
If it exceeds g / mm ² , delamination or large amount of chips tends to be generated when the film is cut or perforated. The sum of the Young's modulus in the vertical direction (Y _MD ) and the Young's modulus in the horizontal direction (Y _TD ) (Y _MD + Y) in order to obtain a base film with good rigidity
_TD ) is preferably 800 kg / mm ² or more.

[Production conditions of laminated film] The laminated base film for photographic film of the present invention is obtained by biaxially stretching an unstretched laminated film obtained by a usual method such as coextrusion.
It can be advantageously produced by heat setting and then annealing.

The stretching method may be a known one, but the stretching temperature is usually 80 to 140 ° C., and the stretching ratio is preferably 1.5 to 4.2 times, more preferably 2.0 to 4.times.
0 times, preferably 2.5 to 5.0 times, more preferably 2.8 to 4.0 times in the horizontal direction. The obtained biaxially stretched film is 170-260 ° C., preferably 180-2 ° C.
Heat set at 50 ° C. for 1 to 100 seconds.

The stretching can be performed by a commonly used method such as a roll method or a method using a stenter. The stretching may be performed simultaneously in the machine direction and the transverse direction, or may be performed sequentially in the machine direction and the transverse direction. .

However, when the proportion of the bis (4- (2-hydroxyethoxy) phenyl) sulfone component in the second layer increases, the non-crystallinity increases, so that the heat setting temperature decreases with the increase in the copolymerization proportion. This is necessary to prevent a decrease in the Young's modulus of the film and maintain the flatness of the film.

When the biaxial stretching process and the heat setting process are performed, a difference in plane orientation occurs between the first and second layers due to a difference in stretching characteristics between the first layer and the second layer. A base film having directional curl is obtained.

Annealing (heat treatment) is 100 to 115
At a temperature of 10 ° C. for 10 minutes to 1000 hours, and further for 1 hour to 30 hours.
It is preferable to carry out under the condition of time.

[0058]

The present invention will be described in more detail with reference to the following examples. In addition, each physical property value in an Example and a comparative example was measured as follows.

(1) Degree of curl in width direction: 1.5 mm in length (longitudinal direction) from the film (width direction)
A test piece of 50 mm is cut out, the radius of curvature (mm) of the test piece is measured, and the reciprocal is used as the degree of curl in the width direction.

(2) Hardness to roll (ANSI curl value) A sample film having a size of 120 mm in length (longitudinal direction) × 24 mm in width (width direction) was placed on a first layer inside, and had a diameter of 7 mm.
mm, and temporarily fix it so that it does not rewind.
After holding at 80 ° C for 2 hours, release from the core, 40 ° C
In distilled water for 15 minutes. Then, a load of 35 g was applied to the longitudinal end of the film, and the sample was suspended vertically.
After holding at 55 ° C. for 3 minutes, the radius of curvature (mm) in the state where the curl remains is measured, and the reciprocal thereof is defined as the curl curl degree.

(3) Optical Density Using a densitometer (TR-310) manufactured by X-Rite, the three primary colors C (Cyan) and M (Mag) of the film sample were measured.
enta) and the optical density at Y (Yellow) are measured.

(4) Haze Total haze value per film measured by a commercially available haze meter according to the method of JIS K-6714.

[0063] (5) set in the endothermic peak temperature TK (° C.) Seiko the film 10mg Electronic Industries Co., Ltd. thermal analysis system SSC5200, DSC220, N ₂
The film is heated in a gas stream at a heating rate of 20 ° C./min, and the endothermic behavior of the film is analyzed by the first derivative and the second derivative to determine the temperature at which the film exhibits a peak, which is defined as the endothermic peak temperature.

(6) Endothermic energy ΔHK (mJ / m
g) In the same manner as in (5), 10 mg of the film was subjected to thermal analysis systems SSC5200 and DSC220 manufactured by Seiko Electronic Industry Co., Ltd.
, And heated at a heating rate of 20 ° C./min in a stream of N ₂ , and determined from the heat absorption side area on the DSC chart corresponding to the heat absorption energy of the film. This area is shifted from the baseline to the endothermic side by increasing the temperature, and is the area on the endothermic side from the endothermic peak after returning to the baseline position after continuing the temperature increase and going through the endothermic peak. To the area (A). Same D
In (indium) is measured under the SC measurement conditions, and the area (B) is determined as 28.5 mJ / mg by the following equation.

[0065]

(A / B) × 28.5 = △ HK (mJ / mg)

(7) Glass transition temperature Tg (° C.) In the same manner as in (5), 10 mg of the second layer film was added to 330
The sample is kept at 3 ° C. for 3 minutes and melted, and then rapidly cooled to prepare a sample. The sample was subjected to a thermal analysis system (differential scanning calorimeter) SSC5200, DSC22 manufactured by Seiko Denshi Kogyo KK
It is set to 0, and heated in a nitrogen stream at a heating rate of 20 ° C./min. This is the midpoint temperature of the region where discontinuity appears in the baseline.

(8) Young's Modulus The film was cut into a sample having a width of 10 mm and a length of 15 cm, and the distance between the chucks was set to 100 mm. The Young's modulus is calculated from the tangent line at the top of the obtained load-elongation curve.

(9) Crease Delamination Whitening Ratio A film was cut out into a size of 80 mm × 80 mm, folded into two by a hand, sandwiched between a pair of flat metal plates, and then pressed at a predetermined pressure P1 (kg / cm) by a press. ² G)
Press for 20 seconds. After pressing, return the folded film to the original state by hand, and sandwich the metal plate with the pressure P1.
(Kg / cm ² G) for 20 seconds. After that, remove the sample and measure the length of the whitened portion that appears on the crease (mm)
Measure and sum.

Using each new film sample, press pressure P1 = 1,2,3,4,5,6 kg / cm
About ² G) to repeat the measurement.

Length of whitened portion at each press pressure (mm)
The ratio of the average value of the total to the total length (80 mm) of the fold is defined as the fold delamination whitening ratio, and this value is used as an index indicating the likelihood of delamination (delamination) of the film.

[0071]

## EQU2 ## (Crease Delamination Whitening Ratio (%)) = ((total length of whitened portion (mm)) / (80 mm × 6)) × 100

Example 1 A pellet of polyethylene-2,6-naphthalenedicarboxylate (intrinsic viscosity = 0.62) is used as a raw material (A) for the first layer. On the other hand, copolymerized polyester (95.0 mol% of ethylene glycol as a glycol component based on a 2,6-naphthalenedicarboic acid component) and a bis (4- (2-hydroxyethoxy) phenyl) sulfone component (BPS-EO and Abbreviated) is copolymerized with 5.0 mol%, intrinsic viscosity = 0.62) The pellets are used as a raw material (B) for the second layer.
Raw material (A) and raw material (B) contain 0.005% by weight of silica particles having an average particle diameter of 0.3 μm. The raw material (A) and the raw material (B) are separately dried and laminated by a co-extrusion method using separate melt extruders, and an unstretched film having a thickness ratio of the first layer and the second layer of 1: 2. I got
Then, the unstretched film is 3.0 times in the longitudinal direction (the direction of film extrusion) and 3.0 times in the lateral direction (the width direction of the film).
1-time sequential biaxial stretching, then heat treatment, thickness 75 μm
Was obtained. Following the heat treatment, the biaxially oriented film was released from gripping in the lateral direction, contacted with a cooling roll in a longitudinally tensioned state, rapidly cooled, and wound around a roll.

The obtained biaxially oriented film is 500 mm wide.
Into a sample roll having a length of 500 m.
The temperature was raised to 10 ° C. for 24 to 72 hours, maintained for 24 hours, and then annealed under annealing conditions of cooling to room temperature for 24 to 72 hours to obtain a biaxially oriented film having a thickness of 75 μm. The properties of the obtained film were good as shown in Table 1.

The raw material (A) and the raw material (B)
Using a raw material containing 0.015% by weight of red and green dyes, a colored base film was obtained in the same manner as in the above base film. The optical density of the obtained colored base film was C = 0.067, M = 0.065, Y = 0.066.
And it was almost uniform and showed good optical density.

[Example 2] In Example 1, the copolymerized polyester (ethylene glycol 93.0 as a glycol component with respect to the 2,6-naphthalenedicarboic acid component) was used.
Mol%, a copolymerized polyester obtained by copolymerizing 7.0% by mol of bis (4- (2-hydroxyethoxy) phenyl) sulfone component, intrinsic viscosity = 0.62) 40% by weight of pellets and polyethylene-2,6-naphthalenediene A base film and a colored base film were obtained in the same manner as above except that a polyester mixture obtained by mixing 60% by weight of carboxylate (intrinsic viscosity = 0.62) pellets was used as a raw material (B). The properties of the obtained base film and colored base film were good as shown in Table 1.

Example 3 A base film and a colored base film were obtained in the same manner as in Example 1, except that the stretching ratio was 2.3 times in length and 3.2 times in width.
The properties of the obtained base film and colored base film were good as shown in Table 1.

[Example 4] In Example 1, the copolymer polyester (ethylene glycol 93.0 as a glycol component with respect to the 2,6-naphthalenedicarboic acid component) was used.
Mol%, a copolymerized polyester obtained by copolymerizing 7.0 mol% of a bis (4- (2-hydroxyethoxy) phenyl) sulfone component, intrinsic viscosity = 0.62) pellets as a raw material (B)
A base film and a colored base film were obtained in the same manner as described above. The properties of the obtained base film and colored base film were good as shown in Table 1.

[Comparative Example 1] In Example 1, the copolymerized polyester (ethylene glycol 99.9 as a glycol component with respect to the 2,6-naphthalenedicarboic acid component) was used.
Mol%, bis (4- (2-hydroxyethoxy) phenyl) sulfone component copolymerized 0.1 mol% copolymerized polyester, intrinsic viscosity = 0.62) pellets as raw material (B)
A base film and a colored base film were obtained in the same manner as described above. Table 1 shows the properties of the obtained base film and colored base film. The biaxially oriented film of Comparative Example 1 did not exhibit the effect of canceling the curl due to the photosensitive agent layer, because the film exhibited insufficient curl in the width direction, which is one of the features of the present invention.

Comparative Example 2 A base film and a colored base film were obtained in the same manner as in Example 1, except that the thickness ratio of the first layer to the second layer was changed to 6: 1. Table 1 shows the properties of the obtained base film and colored base film. The biaxially oriented film of Comparative Example 2 did not exhibit the effect of canceling the curl due to the photosensitive agent layer because the curl in the width direction, which is one of the features of the present invention, was insufficient.

[Comparative Example 3]
The temperature was raised for 24 to 72 hours until the temperature was maintained for 24 hours, and then the temperature was lowered to room temperature for 24 to 72 hours. I got a film. Table 1 shows the physical property evaluation results of the obtained base film and colored base film. The base film and the colored base film of Comparative Example 3 tended to have curl curl and insufficient curl resistance.

[Comparative Example 4] In Example 1, the copolymerized polyester (95.0 ethylene glycol was used as the glycol component with respect to the 2,6-naphthalenedicarboic acid component).
Mol%, a copolymerized polyester obtained by copolymerizing a bis (4- (2-hydroxyethoxy) phenyl) propane component (abbreviated as BPA-EO in the table) with 5.0 mol%, intrinsic viscosity = 0.62) pellets. Except for using the raw material (B), a film was formed in the same manner to obtain a base film and a colored base film. Table 1 shows the properties of the obtained base film and colored base film. The base film and the colored base film of Comparative Example 4 tended to be curled and had insufficient anti-curl properties.

[Comparative Example 5] In Example 5, the copolymerized polyester (95.0 ethylene glycol as a glycol component with respect to the 2,6-naphthalenedicarboic acid component) was used.
Mol%, a copolymerized polyester obtained by copolymerizing 5.0 mol% of 2,2′-dihydroxydiethylether component (abbreviated as DEG in the table, intrinsic viscosity = 0.62) pellets) is used as a raw material (B). Except for the above, a film was formed in the same manner to obtain a base film and a colored base film. Table 1 shows the physical property evaluation results of the obtained base film and colored base film.
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The base film and the colored base film of Comparative Example 5 tended to have curl curl and insufficient curl resistance.

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[Table 1]

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According to the present invention, the film has excellent mechanical properties, curling properties, delamination resistance (delamination) properties, and transparency, and curls in the width direction of the film after the photosensitive agent layer is applied. And a base film for a photographic film having excellent processing characteristics can be provided.

Claims (3)

[Claims] 1. A first layer (a1) comprising (a) polyethylene-2,6-naphthalenedicarboxylate;
A copolyester containing 6-naphthalenedicarboxylic acid as an acid component and ethylene glycol and bis (4- (2-hydroxyethoxy) phenyl) sulfone as a diol component, and / or a copolyester and polyethylene-
A laminated film comprising a second layer (a2) comprising a mixture with 2,6-naphthalenedicarboxylate,
(B) 0.3 mJ / mg in a temperature range of 120 to 160 ° C.
It shows the above endothermic peak, (c) the ratio of the thickness of the first layer to the thickness of the second layer is 1/4 to 4/1, and (d) the total of the thickness of the first layer and the thickness of the second layer. Is 40 to 120 μm, (e) the haze value of the laminated film is 2.0% or less, and (f) the curl degree in the width direction of the laminated film is 5 to 3
0m is ^-1, and (g) photo film for the base film, wherein the longitudinal direction of the curl degree of curl of the laminated film is less than 40 m ^-1. 2. The content ratio of bis (4- (2-hydroxyethoxy) phenyl) sulfone component in the second layer (a2) is 0.2 to 2.0 parts of 2,6-naphthalenedicarboxylic acid component.
The base film for a photographic film according to claim 1, which is 10 mol%. 3. The photographic film base film according to claim 1, wherein the copolymerized polyester of the second layer (a2) is a copolymerized polyester having a glass transition temperature of less than 125 ° C.