JP2889376B2 - Laminated base film for photographic film - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a laminated base film for photographic films. More specifically, a photographic film comprising a first layer of polyethylene-2,6-naphthalenedicarboxylate and a second layer of a polymer composition containing 2,6-naphthalenedicarboxylate units and ethylene units in a total amount of 70% by weight or more. The present invention relates to a laminated base film.

BACKGROUND ART Polyester films, especially polyethylene terephthalate, polyethylene-2,6-naphthalenedicarboxylate and polyester-based films based on these, have excellent heat resistance, chemical resistance, and mechanical properties. , For photography, for electricity, for packaging,
It is used for many purposes such as drafting.

However, although the polyester film has excellent mechanical properties, transparency, and dimensional stability, it expands and contracts with a change in humidity, for example, as compared with a triacetyl cellulose film generally used as a photographic support. Due to the small amount, when a photosensitive emulsion containing a hydrophilic polymer such as gelatin as a main binder is applied, curl is generated due to a difference in shrinkage due to a large expansion and contraction caused by a change in humidity of the emulsion layer, and the work of stretching and printing is performed. The point at which efficiency is reduced is an important issue to be solved.

In recent years, with respect to photographic films, portable and easy-to-use small cameras have been put to practical use, and there is a demand to reduce the film thickness in pursuit of further miniaturization. At that time, the film needs to have high mechanical strength, particularly high breaking strength. On the other hand, a polyethylene-2,6-naphthalenedicarboxylate film having a higher mechanical strength than a polyethylene terephthalate film is promising for thinning. However, polyethylene-2,6-naphthalenedicarboxylate has a drawback that the polymer is likely to be delaminated in the thickness direction because of its rigid structure.

Conventionally, proposals have been made to improve the curl property by facilitating the cancellation of the generated curl and to improve the curl property by reducing the curl property so as not to curl.

JP-A-50-16783 and JP-B-56-53745.
UK Patent No. 1, based on three patent applications
No. 476,343 describes a first crystalline aromatic polyester layer (A) provided on one surface of a laminate, and a second crystalline aromatic polyester layer (A) provided on the other surface of the laminate. B) and optionally a third crystalline aromatic polyester layer (C) between the layers (A) and (B), and the aromatic polyester constituting the layer (A) is 0.1%.
The aromatic polyester constituting the layer (B) has an intrinsic viscosity of 0.37 to 1.0, and has an intrinsic viscosity of 35 to 1.0;
0.02-0.5 than the aromatic polyester constituting the layer
An oriented heat-set laminated film characterized by having a high intrinsic viscosity is disclosed. This laminated film causes curl with the (A) layer on the outside and the (B) layer on the inside, and when a photosensitive layer is applied on the (A) layer side, shrinkage of the photosensitive layer can give a photographic film in which curl is offset. It has been disclosed.

Further, the following proposals have been made from a single layer as a base film for a photographic film.

Japanese Patent Application Laid-Open No. 50-81325 discloses that the ratio of Young's modulus in the vertical and horizontal directions is in the range of 0.9 to 1.1, the saturation shrinkage or expansion at 180 ° C is 0.9% or less, and the saturation at 200 ° C or less. A photographic film based on a biaxially oriented polyethylene-2,6-naphthalenedicarboxylate film having a difference in shrinkage or saturation expansion in a machine direction of 0.4% or less and a haze of 4.5% or less is disclosed. ing.

Japanese Patent Application Laid-Open No. 50-95374 discloses a method for producing a polyester film, which comprises biaxially stretching, heat setting, and heat aging in a temperature range of 40 ° C to 130 ° C. Examples include biaxial stretching at 4.3 times in the machine direction and 3.5 times in the transverse direction, heat setting at 200 ° C., and
A 12 μm thick polyethylene-2,6-naphthalenedicarboxylate film aged at a temperature in the range of 0 ° C. for 24 hours is disclosed.

JP-A-50-109715 discloses an intrinsic viscosity (35 ° C., o-
(In chlorophenol) is at least 0.40 and at least 90 mol% of all constituent units consist of a polyester which is ethylene-2,6-naphthalenedicarboxylate, the haze does not exceed 5% and is biaxially oriented. A photographic film comprising a heat-set film at least as a base material is disclosed.

U.S. Pat. No. 4,141,735 discloses a self-supporting film formed from a thermoplastic polymer having a thickness of about 5-50 mils and a heating rate of 20 DEG K / min, with a Tg measured by DSC of greater than about 60 DEG C. Of the film to reduce the core set curl of the film without substantially deforming or shrinking the film. This method is used at a temperature of 30 ° C. to a temperature of Tg of the polymer and a relative humidity of 100% or less until the core set curl of the film is reduced by at least 15%.
It is carried out by maintaining for about 0.1 to about 1,500 hours. This decrease in core set curl property is due to the change in the number of ANSI curl units when the heat-treated film passes through a core set of 49 ° C., 50% RH for 24 hours on a core having an outer diameter of 3 ″.
It is measured in comparison to the change in number of ANSI curl units through a similar core set of the corresponding film that has not been subjected to the heat treatment as described above.

Table 10 in Example 10 of the same specification shows the heat treatment temperature of a poly (ethylene-2,6-naphthalenedicarboxylate) film having a Tg of 198 ° C. and the net ANSI curl value in the core set curl property. And processing temperature 60 ° C, 71
At 100 ° C., 100 ° C., 120 ° C., 149 ° C. and 180 ° C., the net ANSI curl values are shown to be 18, 16, 13, 16, 20, and 25, respectively.

JP-A-1-244446 discloses a photographic photosensitive material having a polyester base film having a haze of 3% or less and a water content of 0.5% by weight or less and at least one photosensitive layer. The feature of this light-sensitive material is that the base film has a water content of 0.5% by weight or more, and an aromatic dicarboxylic acid component having a metal sulfonate is copolymerized in order to obtain this water content.

DISCLOSURE OF THE INVENTION An object of the present invention is to provide a laminated base film for photographic films.

Another object of the present invention is to provide a laminated base film for a photographic film which has an appropriate widthwise curl which can be eliminated by shrinkage of the photosensitive emulsion and which is excellent in transparency and slipperiness.

Still another object of the present invention is to provide a laminated base film for a photographic film having excellent anti-curling properties, that is, excellent performance in resisting formation of curled curl, transparency and slipperiness.

Still another object of the present invention is to provide a laminated base film for photographic films using polyethylene-2,6-naphthalenedicarboxylate as a material.

Still another object of the present invention is to provide an anti-curling property,
An object of the present invention is to provide a laminated base film for a photographic film which is excellent in curl-removing property, that is, performance in which curling of curl once formed easily proceeds easily.

Still another object of the present invention is to provide a laminated base film for photographic films having excellent delamination resistance and scratch resistance.

Still other objects and advantages of the present invention will become apparent from the following description.

According to the present invention, the above objects and advantages of the present invention include: (A) a first layer consisting essentially of polyethylene-2,6-naphthalenedicarboxylate; and 2,6-naphthalenedicarboxylate. unit And an ethylene unit (-CH ₂ CH ₂ -) is a laminated film comprising a second layer consisting essentially of a polymer composition containing more than 50 wt% in total, (B) a haze value is 3.0% or less, (C) the plane orientation coefficient (NS ₁ ) of the first layer is 0.270 or less;
And (D) the ratio of the thickness of the first layer to the thickness of the second layer is in the range of 3/7 to 7/3.

BEST MODE FOR CARRYING OUT THE INVENTION The laminated base film for a photographic film of the present invention is specified by the constituent elements (A) to (D) as described above.

First, regarding the requirement (A), the base film of the present invention is a laminated film including a first layer and a second layer.

The first layer consists essentially of polyethylene-2,6-naphthalenedicarboxylate.

As the polyethylene-2,6-naphthalenedicarboxylate, a homopolymer having ethylene-2,6-naphthalenedicarboxylate as a total repeating unit or at least 97 mol% of all repeating units is ethylene-2,6-naphthalene carboxylate. A copolymer that is a carboxylate is preferably used.

The third component constituting the copolymer includes 2 in the molecule.
Examples of compounds having two ester-forming functional groups include:
Dicarboxylic acids such as oxalic acid, adipic acid, phthalic acid, isophthalic acid, terephthalic acid, 2,7-naphthalenedicarboxylic acid, diphenyl ether dicarboxylic acid, etc .: p
Oxycarboxylic acids such as oxybenzoic acid, p-oxyethoxybenzoic acid and the like: or propylene glycol;
Trimethylene glycol, tetramethylene glycol,
Examples thereof include dihydric alcohols such as hexamethylene glycol, cyclohexane dimethanol, neopentyl glycol, and diethylene glycol.

Further, the polyethylene-2,6-naphthalenedicarboxylate may have a terminal hydroxyl group and / or a carboxyl group partially or wholly blocked by a monofunctional compound such as benzoic acid or methoxypolyalkylene glycol. Alternatively, it may be modified with a very small amount of a trifunctional or higher-functional polyfunctional compound such as glycerin or pentaerythritol within a range where a substantially linear polymer can be obtained.

As the polyethylene-2,6-naphthalenedicarboxylate, a homopolymer comprising ethylene-2,6-naphthalenedicarboxylate as substantially all repeating units is preferable.

Such polyethylene-2,6-naphthalenedicarboxylate may contain additives such as stabilizers, ultraviolet absorbers, colorants, flame retardants and the like.

The polyethylene-2,6-naphthalenedicarboxylate of the first layer contains a small amount of inert fine particles, for example, an average particle diameter of 0.1.
Inert fine particles of 05 to 1.5 μm can be contained in an amount of 0.2% by weight or less.

As the inert fine particles, those described later for the second layer are preferably used.

The second layer is a 2,6-naphthalenedicarboxylate unit And an ethylene unit (-CH ₂ CH ₂ -) consists essentially of polymer composition containing a total of 7 wt% or more.

This polymer composition is, for example, polyethylene-2,6-
A composition of naphthalenedicarboxylate and another polymer or a copolymerized polyester in which the main acid component is 2,6-naphthalenedicarboxylic acid and the main glycol component is ethylene glycol, or a composition of the same and another polymer Can be.

As the polyethylene-2,6-naphthalenedicarboxylate, the same as described above for the first layer can be used. Further, in the copolymerized polyester, the acid component other than 2,6-naphthalenedicarboxylic acid is 40 mol% or less, preferably 20 mol% or less of the total acid component, and the glycol component other than ethylene glycol is 50 mol% of the glycol component. What is not more than 25 mol%, preferably not more than 25 mol% is used.

As the acid component other than 2,6-naphthalenedicarboxylic acid and the glycol component other than ethylene glycol, the same components as described above can be mentioned. Further, the terminal may be blocked with a monofunctional compound, and a trifunctional or higher functional compound may be copolymerized to some extent in a substantially linear form.

Other polymers include, for example, polyethylene terephthalate homopolymer, copolymerized polyethylene terephthalate in which at least 80 mol% of the acid component is composed of terephthalic acid and at least 90 mol% of the glycol component is composed of ethylene glycol, polycyclohexane dimethylene-2, Examples thereof include 6-naphthalenedicarboxylate, polybutylene terephthalate, polyamide, polyolefin, and polycarbonate. Among these, polyethylene terephthalate and copolymerized polyethylene terephthalate are preferred.

As the other acid component of 20 mol% or less constituting the copolymerized polyethylene terephthalate, the above-mentioned dicarboxylic acids and 2,6-naphthalenedicarboxylic acid other than terephthalic acid can be preferably mentioned. As the other glycol component of 10 mol% or less, a dihydric alcohol as described above can be used.

The polymer composition constituting the second layer comprises a total of 2,6-naphthalenedicarboxylate units and ethylene units of 70% by weight or more, preferably 75 to 99% by weight, more preferably 80% by weight.
It contains about 98.5% by weight.

The polymer composition of the second layer preferably comprises a combination of polyethylene-2,6-naphthalenedicarboxylate and another polymer. Further, the polymer composition of the second layer may contain a polymer composition comprising the composition of the laminated base film of the present invention, for example, a polymer composition comprising the composition of a recovered product of the laminated base film of the present invention.
The polymer composition consisting of the composition of the laminated base film is 2,
When the content of the units other than the 6-naphthalenedicarboxylate unit and the ethylene glycol unit is smaller than a desired value, it is possible to form a second polymer composition having a desired composition by appropriately combining other polymers, for example. it can. The polymer composition of the second layer contains a small proportion of inert fine particles,
For example, an inert fine particle having an average particle size of 0.05 to 1.5 μm is 0.001 to
It can be contained in the range of 0.2% by weight.

Examples of such inert fine particles include silica spherical particles,
Examples include inorganic particles such as calcium carbonate, alumina and zeolite, or organic particles such as silicon resin particles and crosslinked polystyrene particles. When the inert fine particles are inorganic particles, synthetic inorganic particles are preferred, and the crystal form may be any.

Among these, silica spherical particles are one of the preferable inert fine particles. The silica spherical particles each have a particle shape close to a true sphere and have a particle size ratio (maximum diameter / minimum diameter) of preferably 1.0 to 1.2, more preferably 1.0 to 1.1, and particularly preferably 1.0 to 1.05. It is within the range. The silica spherical particles exist in a monodispersed state, and do not mean, for example, spherical particles of primary particles forming aggregated particles. When this spherical ratio increases,
Voids are likely to be generated around the particles, and the generated voids are relatively large to increase haze, which is not preferable.

Further, silicone resin particles and crosslinked polystyrene particles are also preferable other inert fine particles.

As the silicon resin particles, organopolysiloxane particles in which at least 80% by weight of the structural units are composed of structural units represented by CH ₃ · SiO _3/2 are preferred. This structural unit CH ₃・ SiO
_3/2 is the following formula Is represented by Further, the silicon resin particles can be expressed as an organopolysiloxane having a three-dimensional bonding structure in which 80% by weight or more of the structural unit is represented by (CH ₃ .SiO _3/2 ) n. Here, the above n represents the degree of polymerization, and is preferably 100 or more. Other components include a bifunctional organopolysiloxane or another trifunctional organosiloxane derivative.

The silicon resin particles are excellent in lubricity, have a specific gravity smaller than inorganic inert fine particles, and have a characteristic that they have excellent heat resistance than other organic fine particles, and are further insoluble in organic solvents. And is non-melting. Furthermore, the silicone resin particles are polyethylene-2,6-
Shows excellent affinity for naphthalenedicarboxylate. The silicon resin particles further have a volume shape factor of 0.
It is preferably 20 to π / 6. With this property,
The biaxially stretched film has better slipperiness, and the transparency of the film is greatly improved due to the good affinity of the silicone resin particles for polyethylene-2,6-naphthalenedicarboxylate. .

As the crosslinked polystyrene particles, those having a spherical shape and a narrow particle size distribution are preferable. For the shape, the particle size ratio defined by the ratio of the maximum diameter to the minimum diameter is 1.0 to 1.2
, More preferably in the range of 1.0 to 1.15, particularly preferably in the range of 1.0 to 1.12.

Crosslinked polystyrene particles are not restricted by their manufacturing method, for example, spherical crosslinked polystyrene particles,
In addition to styrene derivative monomers such as styrene monomer, methylstyrene monomer, α-methylstyrene monomer and dichlorostyrene monomer, conjugated diene monomer of butadiene, unsaturated nitrile monomer such as acrylonitrile, and methacrylic acid such as methyl methacrylate One or two selected from monomers such as esters, functional monomers such as unsaturated carboxylic acids, monomers having hydroxyls such as hydroxyethyl methacrylate, monomers having epoxide groups such as glycidyl methacrylate, and unsaturated sulfonic acids. As a crosslinking agent for forming a three-dimensional structure of the polymer particles, a polyfunctional vinyl compound such as divinylbenzene,
Ethylene glycol dimethacrylate, trimethylolpropane triacrylate, diallyl phthalate, and the like are emulsion-polymerized in an aqueous medium in which a water-soluble polymer is dissolved as a protective colloid to prepare an emulsion of polymer particles. Can be recovered by drying and then released by a jet mill, and then classified.

The average particle size of the inert fine particles as described above is 0.05 to 1.5 μm
Is preferably within the range. In particular, when the inert fine particles are inorganic particles, the average particle diameter is more preferably in the range of 0.1 to 0.8 μm, and particularly preferably 0.2 to 0.5 μm. When the inert fine particles are silicon resin particles, the average particle diameter is preferably in the range of 0.1 to 1.5 μm,
It is particularly preferred to be in the range of 1.3 μm. When the inert fine particles are cross-linked polystyrene particles, the average particle size is
More preferably, it is in the range of 0.1 to 1 μm.

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 transparency of the film decreases. Is not preferred.

Further, for the particle size distribution of the inert fine particles, the relative standard deviation represented by the following formula is 0.5 or less, further 0.3 or less, particularly 0.
It is preferably 12 or less.

Here, Di is the area circle equivalent diameter (μm) of each particle, Da is the average value of the area circle equivalent diameter, n is the number of particles measured.

When using inert fine particles having a relative standard deviation of 0.5 or less,
Since the particles are spherical and the particle size distribution is very steep, the height of the film surface projections becomes extremely uniform. Furthermore, the individual projections formed on the film surface have very sharp projections, and the film has extremely good slipperiness.

The content of the inert fine particles is preferably 0.001 to 0.2% by weight. When the inert fine particles are inorganic particles, the content is preferably 0.001 to 0.1% by weight, particularly preferably 0.002 to 0.005% by weight.

Further, when the inert fine particles are silicon resin particles, 0.00
1 to 0.1% by weight, more preferably 0.001 to 0.02% by weight, especially 0.001 to
Preferably it is 0.01% by weight. Further, when the inert fine particles are cross-linked polystyrene particles, preferably 0.01 to 0.1
% By weight, particularly preferably from 0.001 to 0.05% by weight. When the amount of the inert fine particles is less than 0.001% by weight, the film tends to have insufficient slipperiness. On the other hand, when the amount exceeds 0.2% by weight, the film haze increases and the transparency becomes insufficient.

The timing of adding the inert fine particles is not particularly limited as long as it is a stage before forming the polymer composition, and may be, for example, a polymerization stage of the polymer to be used, or may be added to the polymer composition at a stage before the film formation. Is also good.

The haze value of the laminated base film for photographic films of the present invention is 3.0% or less (requirement (B)). The haze value is preferably 2.0% or less, more preferably 1.5% or less, particularly preferably 1.0% or less. If the haze is too high, the transparency of the film decreases, which is not preferable.

In the laminated base film of the present invention, the plane orientation coefficient (NS ₁ ) of the first layer is 0.270 or less (requirement (C)), preferably
0.260 or less. The plane orientation coefficient (NS) is defined by the following equation.

Here, n _x represents a mechanical axis direction of the refractive index of biaxially oriented film, n _y represents a refractive index in a direction (axial direction) perpendicular to the mechanical axis direction, n _z is a refractive index in the thickness direction of the film Represents

When the plane orientation coefficient (NS ₁ ) of the first layer exceeds 0.270, the degree of plane orientation is too high and the film is liable to cause delamination in the thickness direction.

Laminated base film of the present invention, preferably the difference between the plane orientation coefficient of the second layer (NS ₂₎ and plane orientation coefficient of the first layer _{(NS 1) (△ NS =} NS 1 -NS 2) is 0.002 to 0.200 In the range. △ NS
Is in this range, the film is easily curled by the film formation, and the film forming property is very easy.

The laminated base film of the present invention has a thickness of the first layer versus the second layer.
The thickness ratio of the layers is between 3/7 and 7/3 (Requirement (D)), preferably between 3/7 and 1/1.

The laminated base film of the present invention is a biaxially stretched unstretched laminated film obtained by a usual method such as co-extrusion,
It can be advantageously prepared by heat setting and, if appropriate, annealing. The stretching method may be a known method, the stretching temperature is usually 80 to 140 ° C., and the stretching ratio is preferably 2.0 to 4.2 times in the longitudinal direction, more preferably 2.
It is 5 to 4.0 times, preferably 2.5 to 4.3 times, more preferably 2.8 to 4.0 times in the lateral direction. The obtained biaxially stretched film is heat-set at 170 to 260 ° C., preferably 180 to 250 ° C. for 1 to 100 seconds. The stretching may be carried out simultaneously in the vertical and horizontal directions by using a general roll or a stenter, or may be carried out by a method of successively stretching in the vertical and horizontal directions.

When the biaxial stretching process and the heat setting process are performed, a difference in plane orientation occurs between the first layer and the second layer due to a difference in stretching characteristics, and a difference in shrinkage stress occurs due to the difference between the first layer and the first layer. Thus, a curled laminated polyester film having the second layer inside is obtained.

Further, in the heat setting of the biaxial stretching, the heat setting zone after the biaxial stretching is divided into multiple stages, and the heat setting temperature is gradually reduced so as not to give a rapid temperature change. It is easy to increase the refractive index (nz) in the thickness direction without causing the occurrence of. Further, when the width of the stenter rail is reduced in the heat fixing zone at the highest temperature to cause the film to contract in the width direction, this effect becomes more remarkable.

For example, the heat setting zone after biaxial stretching is 3 or more zones,
It is preferable to divide the heat setting zone into four or more zones, and to set the temperature of the final zone of the heat setting zone to 140 ° C. or lower, preferably 120 ° C. or lower.

From the zone with the highest heat setting temperature to the final zone,
It is preferable to gradually lower the temperature so as not to give a rapid temperature change. In this case, the temperature gradient between the zones is 70 ° C. or less, preferably 60 ° C. or less.

The laminated base film of the present invention can further have the following preferable properties as a base film for a photographic film.

Laminated base film of the present invention is preferably in the range width direction of the curl degree (f ₁₎ is 0.5 to 50% by the inner second layer. That is, the laminated base film of the present invention is
Indicates the nature of flex in the width direction of the layer as an inner, its degree is in the range 0.5 to 50% in the value of the curl degree (f _1). The laminated base film of the present invention exhibiting this degree of curl (f ₁ ) is preferable because when the photosensitive emulsion is coated on the first layer side, the curl is exactly eliminated by the drying shrinkage.

The refractive index nz in the thickness direction of the first layer of the laminated base film for photographic films of the present invention is preferably at least 1.493. When the refractive index (nz) is less than 1.493, the film is liable to cause delamination, and scratches due to scratching are liable to have scratches (unevenness), and the delamination portion and the scars become white and unsuitable. It is.

Here, the refractive index (nz) in the thickness direction of the film is a value obtained for an Na-D line at 25 ° C. by an Abbe refractometer.

In order to increase the refractive index (nz), the stretching ratio of the film may be reduced and the heat setting temperature may be increased. However,
If the draw ratio is too low or the heat setting temperature is too high,
The thickness unevenness of the film becomes large, and wrinkles (flutes) occur on the film surface.

The refractive index (nz) is preferably 1.495 or more. 1.510 or less is more preferable.

The film-to-film hardness of the laminated base film of the present invention is preferably tertiary or less, more preferably 2.5 or less, and particularly preferably 2 or less. The higher the grade of the degree of hardness, the more difficult the film is to slip, while the smaller the grade, the more the films tend to slip. If the degree of stiffness is higher than class 3, slippage between films is poor, occurrence of blocking between films, occurrence of scratches due to a transport roll or the like during film running, and easy occurrence of bump-like projections on the roll when the roll is wound up. It is not preferable for use as a photographic film.

The laminated base film of the present invention preferably has a degree of curl (f ₂ ) in the longitudinal direction of 0 to 70% with the first layer being inside and the second layer being outside after winding.

Such a property, that is, the degree of curl (f ₂ ) in the longitudinal direction is 0 to
The laminated base film of the present invention in the range of 70% can be advantageously produced by subjecting an unstretched laminated film obtained by a usual method to biaxial stretching, heat setting, and then annealing.

As a method of annealing the biaxially stretched laminated film, a method of heating while contacting the heating roll without once winding the film that has been biaxially stretched and heat set,
A method in which the film is heated in a non-contact manner while being conveyed by heated air, a method in which the film is once wound and heated in the same manner as described above, or a method in which the film is heat-treated in a heating oven in a roll state, and the like. .

The film is subjected to a heat history in a roll state and is higher than 150 ° C. or lower, and even 10 °
A method of annealing at a temperature higher by 130 ° C. and lower than 130 ° C. is more effective and preferable. Even if the film is annealed at a temperature equal to or lower than the temperature at which the film is subjected to the heat history in the roll state, it is insufficient to prevent curling, and if the annealing is performed at a temperature higher than 150 ° C., precipitation of oligomers on the film surface and It is not preferable because core transfer or the like easily occurs on the film surface, which causes inconvenience in using the film.

The flatness of the laminated base film of the present invention is preferably not more than 250 cm / m width. Film flatness is 2
If the width exceeds 50 cm / m, uniform coating of the photosensitive emulsion becomes difficult and unsuitable. The flatness is particularly preferably not more than 200 cm / m width.

The laminated base film of the present invention preferably allows uneven thickness of 5 μm or less, more preferably 4 μm or less. If the thickness unevenness exceeds 5 μm, it becomes difficult to apply the photosensitive emulsion uniformly to the film surface, and the quality of the photographic film may be reduced.

In order to reduce thickness unevenness, it is effective to increase the draw ratio and to lower the heat setting temperature, longitudinal stretch temperature, and transverse stretch temperature.

Further, the laminated base film of the present invention preferably has a Young's modulus in two orthogonal directions of 750 kg / mm ² or less,
More preferably, it is not more than kg / mm ² . This Young's modulus is 75
If it exceeds 0 kg / mm ² , a large amount of chips tends to be generated at the time of cutting the film or at the time of perforation perforation. The lower limit of the Young's modulus in both the vertical and horizontal directions is 400 kg / mm ² , and even 4
Preferably, it is 50 kg / mm ² .

The difference in Young's modulus in both directions is not particularly limited, but is 150 kg /
It is preferably not more than mm ² .

The laminated base film of the present invention is preferably 40 to 120 μm.
m, more preferably 50 to 100 μm.

Various thin layers including a photosensitive emulsion layer can be formed on the surface of the laminated base film of the present invention to obtain a photographic film. Known means can be used for forming these thin layers.

Examples Hereinafter, the present invention will be described in more detail with reference to Examples.
The present invention is not limited to these examples.

In addition, each physical property value is measured as follows.

(1) Plane Orientation Coefficient The refractive index of each surface was measured by an Abbe refractometer using a Na-D line at 25 ° C as a light source. The film orientation was measured on both sides of the first layer and the second layer of the film sample, and the plane orientation coefficient (NS
₁ ) and the plane orientation coefficient (NS ₂ ) of the second layer are determined by the following equations.

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

(3) Degree of curl in the width direction (f ₁ ) A test piece of 3 mm long × 120 mm wide was cut out from the film immediately after film formation, the test piece was suspended vertically, and the length of the curled chord X (mm) Is measured, and the degree of curl is determined from the following equation using the ratio (%) to the sample length of 120 mm.

The curl with the second layer inside is + and the curl with the first layer inside is one, and the determination is made as follows.

：: + 0.5 ≦ curl degree f ₁ ≦ + 50 Δ: +0 <curl degree f ₁ <+0.5 or +50 <curl degree f
₁ ×: + 0 ≧ curl degree f ₁ (4) Curl degree in the longitudinal direction (f ₂ ) A sample film having a size of 120 mm × 35 mm is wound around a core having a diameter of 10 mm with the first layer on the inside so as not to rewind. Temporarily fixed, heated at 70 ° C, 30% RH for 72 hours, released from the core, immersed in distilled water at 40 ° C for 15 minutes, then
Apply a load of 50 g, suspend the sample vertically, measure the "sample length" x (mm) in the state where the curl remains, and first determine the ratio (%) to the sample length of 120 mm in the longitudinal direction. the degree of curl f _2.

In this case, the "sample length" is the diameter when the sample is curled greatly and has a circular to semi-circular shape, and is the chord length when the curl of the sample is small and its shape is less than a semi-circle. .

The closer the degree of curl in the longitudinal direction is to zero (0), the better the curl resolving property is.

(5) Degree of chipping A rubber plate is laid on a flat table, and two films free of dust and dirt are placed between the films on the rubber plate. Outer diameter
Place a 70mm, 10kg weight cylindrical weight on the film gently from above, remove the weight gently after 10 minutes, leave it for 30 seconds, and then project the contact pattern in the circle inside the cylinder of the cylinder trace. ,
The ratio of the area of the sharpness portion is measured, and the results are rated from Table 1 on a scale of 0 to 5.

(6) Flatness A film sample having a length of 2 m is collected from a film roll and spread on a horizontal flat table with the side that was the front side of the roll when wound on the roll facing up. After standing for 10 minutes, observe the entire surface of the film sample, measure the length (cm) of wrinkles (flute) remaining on the surface, and divide the total by the width (m) of the film to obtain the flatness. calculate.

(7) Unevenness of film thickness Using an electronic micrometer model K-312A manufactured by Anritsu Corporation, measured at a stylus pressure of 30 g and a running speed of 25 mm / sec over a length of 2 m each in the longitudinal direction and the lateral direction of the film, and ±
A continuous thickness chart with a sensitivity of 4 μm is obtained. From this chart, the maximum value and the minimum value of the thickness over 2 m are obtained, and the difference R (μm) is defined as the thickness unevenness.

(8) Young's modulus Cut the film into a sample width of 10 mm and a length of 15 cm.
Pull at 100mm and pull at 10mm / min and 500mm / min chart speed with an Instron type universal tensile tester. The Young's modulus is calculated from the tangent at the rising portion of the obtained load-elongation curve.

(9) Cut out a film sample to a size of 80 mm x 80 mm
While folding the two lightly by hand the first layer on the outside, after sandwiched between pair of flat metal plates, the press predetermined pressure P ₁
(Kg / cm ² G) for 20 seconds. After pressing, the folded film is returned to the original state by hand, and is pressed between the metal plates at a pressure P1 (kg / cm ² G) for 20 seconds. afterwards,
The sample film is taken out, and the length (mm) of the whitened portion appearing on the fold is measured and totaled.

Using each new film sample, the above measurement is repeated with a press pressure P ₁ = 1,2,3,4,5,6 (kg / cm ² G).

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

(10) Average particle size of particles Shimadzu Corporation CP-50 Centrifugal Particle Size Analyzer
Analyzer). The particle size corresponding to 50 mass percent (mass parcent) was read from the cumulative curve of the particles having each particle size and the amount present based on the obtained stretch settling curve, and this value was defined as the above average particle size ( "Granularity measuring technology", published by Nikkan Kogyo Shimbun, 1975, pp. 242 to 247).

(11) Volume shape factor (f) A photograph of the lubricant granules was taken with a scanning electron microscope at 5,000 times magnification.
The field of view is photographed, the average value of the maximum diameter is calculated for each field of view using an image analysis processing device Luzex 500 (manufactured by Nippon Regulator), and the average value of 10 fields of view is determined.

Using the average particle diameter d of the particles obtained in the above item (10), the volume of the particles is calculated by V = (π / 6) d ³ , and the shape factor f is calculated by the following equation.

f = V / D ³ where V is the volume of the particle (μm ³ ), and D is the maximum diameter of the particle (μ
m).

(12) Particle size ratio A small piece of film is fixedly formed with epoxy resin, and an ultrathin section (cut parallel to the film flow direction) with a thickness of about 600 angstroms is created with a microtome.
This sample was transferred to a transmission electron microscope (H-800, manufactured by Hitachi, Ltd.).
(Mold) to observe the cross-sectional shape of the lubricant in the film, and expresses the ratio of the maximum diameter to the minimum diameter of the particles.

(13) Average particle size, particle size ratio, etc. Particles are scattered on an electron microscope sample stand so that the individual particles do not overlap as much as possible, and a gold thin film deposition layer having a thickness of 200 to Formed with a 300 angstrom, observed at a magnification of 10,000 to 30,000 with a scanning electron microscope, and using Luzex 500 manufactured by Nippon Regulator Co., Ltd., the maximum diameter (Dli) and minimum diameter (Dsi) of at least 100 particles. And the area circle equivalent (Di). Then, the maximum diameter (Dl), the minimum diameter (Ds), and the average particle diameter (Da) of the particles are represented by the number average values represented by the following equations. Further, the particle size ratio is determined from this.

Further, the particles in the film are determined as follows.

A small piece of the sample film was fixed on a sample table for a scanning electron microscope, and a sputtering device (JFC-110 manufactured by JEOL Ltd.) was used.
The surface of the film is subjected to ion etching under the following conditions using a 0-type ion etching apparatus). The conditions are as follows. A sample is placed in a bell jar, the degree of vacuum is raised to a vacuum of about 10 ⁻³ Torr, and ion etching is performed at a voltage of 0.25 KV and a current of 12.5 mA for about 10 minutes. Further, the same apparatus was used to perform gold sputtering on the film surface, and the scanning electron microscope was used for 10,000.
Observed at a magnification of ~ 30,000 times, the maximum diameter of at least 100 particles (Dl
i), (Calculate minimum diameter (Dsi) and area circle equivalent diameter (Di).

Example 1 Polyethylene-2,6-naphthalenedicarboxylate containing 0.01% by weight of silica particles having an average particle size of 0.5 μm was used as a raw material (A). On the other hand, polyethylene-
A raw material (B) was obtained by blending 10% by weight of polyethylene terephthalate (α component) as a component other than 2,6-naphthalenedicarboxylate. These raw materials (A) and (B) were separately dried, extruded by separate melt extruders, and laminated by a co-extrusion method to obtain an unstretched film having a thickness constituting ratio of 50:50. This unstretched film is biaxially stretched sequentially 3.0 times in the machine direction (machine direction) and 3.1 times in the transverse direction (width direction).
It was heat-set at 20 ° C. for 30 seconds to obtain a laminated biaxially oriented polyester film having a thickness of 100 μm. From the obtained biaxially oriented film, a film having a width of 500 mm and a length of 500 m was sampled, taken up on a core having a diameter of 165 mm, and used as a sample roll.In this state, the temperature was raised to 100 ° C over 24 hours, Two
After holding for 4 hours, an annealing treatment for lowering the temperature to room temperature over 24 hours was performed. Table 1 shows the physical properties of the biaxially oriented film subjected to the annealing treatment.

Examples 2 and 3 In Example 1, the weight% of polyethylene terephthalate blended with the raw material (A) of the composition (B) was 30%.
(Example 2) or 50% (Example 3), average particle size
The same procedure was carried out except that 0.01% by weight of 0.3 μm silica particles was contained. Table 1 shows the results.

Example 4 The same procedure as in Example 1 was carried out except that the thickness constituting ratio was 33:67. Table 1 shows the results.

Example 5 In Example 1, the thickness ratio was set to 67:33, and the amount of the lubricant contained was set to 0.05 μm.
The same procedure was performed except that the amount was 1% by weight. Table 1 shows the results.

Example 6 The same procedure was performed as in Example 1, except that 5% by weight of polycarbonate was blended as a component other than polyethylene-2,6-naphthalate to be blended with the raw material (A) of the composition (B). Table 1 shows the results.

Comparative Example 1 The same procedure as in Example 1 was carried out except that a film having a thickness of 10 μm was prepared using only the raw material (A) alone. The results are also shown in Table 1.

Comparative Example 2 The same procedure as in Example 1 was carried out except that sequential biaxial stretching was performed 4.8 times in the longitudinal direction and 5.1 times in the horizontal direction. The results are also shown in Table 1.

Comparative Example 3 The procedure of Example 1 was repeated, except that 0.30% by weight of titanium dioxide particles having an average particle diameter of 0.3 μm was contained instead of the silica particles. The results are also shown in Table 1.

Example 7 In Example 1, as a component other than polyethylene-2,6-naphthalenedicarboxylate blended with the raw material (A) of the raw material (B), polysiloxane dimethylene-2,6-
25% by weight of naphthalenedicarboxylate is blended,
All films were formed in the same manner except that 0.01% by weight of silica particles having an average particle diameter of 0.3 μm was contained. Table 1 shows the results.

Examples 8 to 10 and Comparative Example 5 Polyethylene-2,6-naphthalenedicarboxylate containing 0.01% by weight of silica particles having an average particle size of 0.5 μm was used as a raw material (A). On the other hand, polyethylene-
A raw material (B) was obtained by blending 10% by weight of polyethylene terephthalate (α component) as a component other than 2,6-naphthalenedicarboxylate. These raw materials (A) and (B) were separately dried, extruded by separate melt extruders, and laminated by co-extrusion to form an unstretched film having a thickness ratio of 50:50. . The unstretched film was biaxially stretched and heat-treated under the conditions shown in Table 2 to obtain a biaxially oriented film having a thickness of 75 μm. Incidentally heat treatment performed using the apparatus divided heat treatment zone 4 zone _{X 1, X 2, X 3} , X 4, the highest heat-setting temperature zones (X ₁₎ in, narrowing the width of stenter rails To give shrinkage in the width direction of the film.

With respect to each of the obtained biaxially oriented films, the Young's modulus in the vertical direction and the horizontal direction, the refractive index (nz) in the thickness direction, the thickness unevenness in the vertical direction and the horizontal direction, the flatness, and the fold delamination whitening ratio were measured.

 The results were as shown in Table 2.

Continuation of the front page (56) References JP-A-7-56275 (JP, A) JP-A-6-202279 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03C 1 / 795

Claims (16)

(57) [Claims] 1. A first layer consisting essentially of (A) polyethylene-2,6-naphthalenedicarboxylate, and 2,6
-Naphthalene dicarboxylate units And an ethylene unit (-CH ₂ CH ₂ -) is a laminated film comprising a second layer consisting essentially of a polymer composition containing more than 50 wt% in total, (B) a haze value is 3.0% or less, (C) the plane orientation coefficient (NS ₁ ) of the first layer is 0.270 or less;
(D) The laminated base film for photographic films, wherein the ratio of the thickness of the first layer to the thickness of the second layer is in the range of 3/7 to 7/3. 2. The method according to claim 1, wherein the polymer composition of the second layer is polyethylene-
The laminated base film according to claim 1, comprising a combination of 2,6-naphthalenedicarboxylate and another polymer. 3. The laminated base film according to claim 1, wherein the polymer composition of the second layer contains a polymer composition comprising the composition of the laminated base film of claim 1. 4. The laminated base film according to claim 1, which has a haze value of 2.0% or less. 5. The laminated base film according to claim 1, wherein the plane orientation coefficient (NS ₁ ) of the first layer is 0.260 or less. 6. A laminated base film of claim 1 the difference between the plane orientation coefficient of the second layer (NS ₂₎ and plane orientation coefficient of the first layer (NS ₁₎ (△ NS) is in the range of 0.002 to 0.200 . 7. The ratio of the thickness of the first layer to the thickness of the second layer is 3/7 to 1
2. The laminated base film of claim 1 in the range of / 1. 8. The laminated base film according to claim 1, wherein the curl degree (f ₁ ) in the width direction with the second layer inside is in the range of 0.5 to 50%. 9. The laminated base film according to claim 1, wherein the refractive index (nz) in the thickness direction is 1.493 or more. 10. The degree of stiffness between laminated base films is 3
2. The laminated base film according to claim 1, which is less than or equal to grade. 11. The degree of curl (f ₂ ) in the longitudinal direction of 0 to 70% with the first layer inside and the second layer outside after winding.
The laminated base film according to claim 1, wherein 12. The laminated base film according to claim 1, wherein the flatness is not more than 250 cm / m width. 13. The laminated base film according to claim 1, which has one direction in which unevenness in thickness is 5 μm or less. 14. An orthogonal ² having a Young's modulus of 750 kg / mm ² or less.
The laminated base film of claim 1 having a direction. 15. The first layer may contain 0.2% by weight or less of inert fine particles having an average particle size of 0.05 to 1.5 μm, and the second layer may contain inert fine particles having an average particle size of 0.05 to 1.5 μm. 0.0
The laminated base film according to claim 1, which is contained in the range of 01 to 0.2% by weight. 16. The laminated base film according to claim 1, which has a thickness of 40 to 120 μm.