JP3318230B2 - Base film for photographic film consisting of polyethylene naphthalate copolymer - Google Patents

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 comprising a polyethylene naphthalate copolymer, and more particularly to a base film having excellent delamination resistance, anti-curl properties, mechanical strength, hue and transparency. polyethylene naphthalate copolymer capable of forming a film
Or on Ranaru photographic film for the base film.

[0002]

2. Description of the Related Art Triacetate films have conventionally been used as a base material for photographic films. Since the triacetate film uses an organic solvent in the production process, it has safety and environmental problems. There are also disadvantages such as limitations on mechanical strength and dimensional stability. For this reason, polyethylene terephthalate film has come to be used partially as a substitute material. However, when stored in a state in which the film is wound, there is a property that a strong curl (curl) remains, and it must be removed. Therefore, the handleability after the development processing is poor, and it has been difficult to use it for a photographic film used as a roll film.

[0003] As a technique for improving the anti-curl property, Japanese Unexamined Patent Publication Nos. 53-146773 and 1-244446 disclose a modified polyethylene terephthalate film having improved water vapor permeability and water content. Has been proposed. Although these were effective in terms of curl reduction, they had drawbacks such as a decrease in dimensional stability due to moisture absorption and an increase in deformation of the film end face due to a decrease in glass transition temperature, and were insufficient. .

In recent years, the quality requirements for photographic films have become more sophisticated. For example, in the case of roll films, the speed of film transport during photographing and the size of photographing apparatuses have been reduced.
There is a demand for performance such as exhibiting excellent curl resistance even when wound with a small winding diameter, and having good mechanical strength and dimensional stability even when formed into a thin film. Neither the triacetate film nor the modified polyethylene terephthalate film can sufficiently respond to these demands, and a photographic film having excellent properties is required.

[0005] In order to respond to this, application of a polyethylene naphthalate (PEN) film to a photographic film,
For example, JP-B-48-40414 and JP-A-50-414
No. 109715, and the like. These films were satisfactory to some extent about the adaptability of thin films such as mechanical strength and dimensional stability, and the anti-curl properties when wound with a small winding diameter. However, delamination (delamination) occurred on the films. Roll films tend to occur, and in particular, roll films have a new problem that delamination occurs when perforation holes are formed. In this case, the delaminated portion becomes white, making it difficult to use it as a base film for a photographic film.

[0006]

DISCLOSURE OF THE INVENTION In view of the above circumstances, the present inventors have made intensive studies to develop a polymer and a film suitable for a base film of a photographic film. As a result, the present inventors have found that a polyethylene naphthalate copolymer having a specific composition is obtained. The present inventors have found that a film has excellent characteristics as a base film for a photographic film and can solve the above-mentioned problems, and have accomplished the present invention.

An object of the present invention has excellent resistance to delamination resistance, anti-curling property, mechanical strength, polyethylene naphthalate copolymer or Ranaru photo film for the base film capable of forming a film having both hue and transparency Is to provide.

[0008]

SUMMARY OF THE INVENTION The object of the present invention is to provide: Naphthalenedicarboxylic acid is used as a main acid component, ethylene glycol is used as a main glycol component, and a fluorene compound having an ester-forming functional group is used as a copolymer component in the glycol component in an amount of 0.
5 to 5 mol%, and consists of Lupolen Li ethylene naphthalate copolymer to contain 3 mole% or less of diethylene glycol component relative to the total acid component, an anti-curling properties at 80 ° C.
Is less than 50 [m ^-1 ] in ANSI curl value , and
Delamination property is 10% or less in crease delamination whitening rate
This is achieved by a base film for a photographic film. Hereinafter, the present invention will be described in detail.

[Polyester Copolymer] In the present invention, the main dicarboxylic acid component constituting the polyethylene naphthalate copolymer is naphthalenedicarboxylic acid, and the main glycol component is ethylene glycol.

In the present specification, the main acid component means at least 80 mol%, preferably at least 90 mol%, based on the total acid component, and the main glycol component means at least 80 mol%, preferably at least 90 mol%, based on the total glycol component. Means 90 mol% or more.

Examples of the naphthalenedicarboxylic acid include 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, and 1,5-naphthalenedicarboxylic acid. Is preferred.

In the present invention, the polyethylene naphthalate copolymer is obtained by copolymerizing a fluorene compound having an ester-forming functional group as a copolymer component in the glycol component in an amount of 0.5 to 5 mol% based on all acid components. There is a need. If the copolymerization amount of the fluorene compound having an ester-forming functional group is less than 0.5 mol% with respect to the total acid components, the delamination resistance of the film is not improved, and if it exceeds 5 mol%, the film In this case, not only the crystallinity is impaired but the mechanical strength is poor, but also the anti-curl property is reduced.

As a preferred fluorene compound having an ester-forming functional group, 9,9-bis [4- (2-hydroxyethoxy) phenyl] fluorene can be mentioned as a preferred example.

In the present invention, the amount of the diethylene glycol component present in the polyethylene naphthalate copolymer must be 3 mol% or less based on the total acid component.

This diethylene glycol component is not copolymerized by being added as a copolymer component in the form of diethylene glycol or its ester-forming derivative, but by-produced in the course of production of the polyester copolymer. It is.

When the copolymerization amount of the diethylene glycol component exceeds 3 mol%, the effect of improving the delamination resistance of the film becomes large, but the crystallinity is impaired, so that the mechanical strength is greatly reduced, Not preferred.

The polyethylene naphthalate copolymer according to the present invention may contain other bifunctional carboxylic acid components in an amount of, for example, 10 mol%, preferably 5 mol% or less of the total acid components, as long as the effects of the present invention are not impaired. Alternatively, another glycol component may be copolymerized in a proportion of 10 mol%, preferably 5 mol% or less of all glycol components. Examples of the bifunctional carboxylic acid component include aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid; oxycarboxylic acids such as oxybenzoic acid; aliphatic carboxylic acids such as adipic acid; and alicyclic carboxylic acids such as cyclohexanedicarboxylic acid. Acids and the like can be exemplified. Examples of the glycol component include aliphatic glycols such as trimethylene glycol and tetramethylene glycol; alicyclic glycols such as cyclohexanedimethanol; hydroquinone;
Examples include aromatic glycols such as bis (4-hydroxyethoxyphenyl) propane.

The polyethylene naphthalate copolymer in the present invention is substantially linear, but, unless the effects of the present invention are impaired, for example, in a range of 2 mol% or less based on the total acid component, a trifunctional or higher functional group. A polycarboxylic acid or a polyhydroxy compound such as trimellitic acid or pentaerythritol may be copolymerized.

[Additives] In the polyethylene naphthalate copolymer of the present invention, for example, a lubricant, a pigment, a dye, an antioxidant may be used as long as the transparency, surface flatness and thermal stability of the film are not impaired. If necessary, additives such as a light stabilizer and a light-shielding agent may be added.

[Lubricant] The film of the present invention is preferably imparted with lubricity depending on the mode of use. As a means for imparting lubricity, a known method can be used. For example, a method of dispersing lubricant particles in a polymer, a method of providing a layer having lubricity on the film surface, and the like can be preferably used. .

Examples of the method for dispersing the lubricant particles in the polymer include a method in which one or more of SiO ₂ , BaSO ₄ , CaCO ₃ , aluminosilicate, crosslinked organic particles, and the like are added to the polymer, and a catalyst in the polymerization of polyethylene naphthalate. A method of depositing a residue or the like can be given.

A preferred method for dispersing the lubricant particles in the polymer is to add the lubricant particles to the polymer. According to this method, the effect of imparting lubricity is remarkable.

A particularly preferred method in this method is a method in which lubricant particles having a refractive index close to that of the polyethylene naphthalate copolymer, for example, BaSO ₄ , aluminosilicate, and crosslinked organic particles (for example, crosslinked polystyrene) are added. . According to this method, the lubricity can be effectively imparted, and the transparency of the film can be kept high.

The method of providing a layer having lubricity on the surface of the film is preferably a method of thinly laminating a layer having lubricant particles on at least one surface of a polyethylene naphthalate film substantially containing no lubricant particles. According to this method, a film having good lubricity and transparency can be obtained. In this method, in the lamination, it is preferable that a plurality of extruders and a feed block or a multi-manifold are combined and co-extruded for lamination.

[Thickness] The thickness of the film in the present invention can be appropriately selected according to the form of use of the photographic film used as the base film, but is preferably 25 to 250 μm.
m, particularly preferably 40 to 150 μm.

[Anti-curling property] The base film for a photographic film of the present invention is required to have a property of hardly curling and curling, that is, an anti-curling property. Must be 50 [m ^-1 ] or less. This 80
C is an approximate value of the maximum temperature to which a photographic film can be normally exposed in daily life. If the ANSI curl value exceeds 50 [m ^-1 ], it becomes difficult to handle in the photographic processing step, which is not preferable.

Conventionally, the evaluation of curling of a photographic film is as follows.
It depends on the extent to which the curl is eliminated through the usual photo film development or drying process. However, if the base film for a photo film has the above ANSI curl value, the curl of the curl is hard to occur. It has excellent properties, that is, anti-curling properties, and also has excellent curling-removing properties, in which curling once formed is easily resolved.

[Delamination Resistance] In the present invention, the delamination resistance is expressed by using the fold delamination whitening ratio as an index. In the present invention, the fold delamination whitening ratio is defined as the ratio of the length of the whitened portion generated when the film is bent to the entire length of the folded portion of the film.

The film of the present invention is required to have a delamination resistance of not more than 10% in terms of a fold delamination whitening ratio. When the delamination resistance is 10% or less, it is possible to suppress the occurrence rate of the whitening phenomenon that occurs when a perforation hole is formed as a photographic base film.

[Production Method] The polyethylene naphthalate copolymer of the present invention comprises an acid component having the above-mentioned naphthalenedicarboxylic acid or a lower alkyl ester thereof as a main component, ethylene glycol and a fluorene compound having an ester-forming functional group. It can be produced by polycondensing a glycol component as a main component. Preferably, a reaction product obtained by subjecting an acid component mainly containing a lower alkyl ester of naphthalenedicarboxylic acid to a glycol component mainly containing ethylene glycol and a fluorene compound having an ester-forming functional group as a main component, Is produced by polycondensation. When a film is formed using the polyethylene naphthalate copolymer produced by this method, a film having good hue and good transparency can be obtained.

The lower alkyl ester of naphthalenedicarboxylic acid includes, for example, dimethyl ester, diethyl ester and dipropyl ester. Preferably, it is a dimethyl ester.

For producing the film of the present invention, a conventionally known method can be applied. For example, a polyethylene naphthalate copolymer is melted, extruded into a sheet, cooled with a cooling drum to obtain an unstretched film, and then the unstretched film is stretched biaxially and heat-fixed, if necessary. It can be manufactured by heat relaxation treatment. Since the surface characteristics, density, and heat shrinkage of the film at that time vary depending on the stretching conditions and other manufacturing conditions, the film is formed by appropriately selecting the conditions as needed.

Among them, in the above production method, the polyethylene naphthalate copolymer may be used at a temperature between Tm + 10 ° C. and Tm +
It is melted at a temperature of 30 ° C. (where Tm represents the melting point of the polyethylene naphthalate copolymer) and extruded to obtain an unstretched film, and the unstretched film is subjected to Tg-10 in a uniaxial direction (longitudinal or transverse direction). C. to Tg + 50.degree. C. (where Tg represents the glass transition temperature of the polyethylene naphthalate copolymer) at a magnification of 2 to 5 times, and then in a direction perpendicular to the above stretching direction (the first stage stretching is a longitudinal direction). In the case of (2), the second stage is in the horizontal direction), it is preferable to stretch at a temperature of Tg to Tg + 50 ° C. at a magnification of 2 to 5 times.

Thereafter, the film is preferably heat-set at a temperature of Tg + 60 ° C. to Tg + 120 ° C. of the polyethylene naphthalate copolymer for 0.2 to 20 seconds. When the temperature and time for heat setting are within these ranges, a film having excellent delamination resistance and anti-curl properties and high transparency can be obtained.

[0035]

The present invention will be described below in more detail with reference to examples. In addition, each characteristic value in an Example was measured by the following method. In the examples, “parts” means “parts by weight”. Diethylene glycol may be abbreviated as DEG. Hitachi 263-70 was used for gas chromatography, and Hitachi R-1900 was used for ¹ H-NMR.

(1) Intrinsic viscosity Measured at 35 ° C. in a phenol / tetrachloroethane (6: 4 weight ratio) mixed solvent.

(2) Copolymerization amount of fluorene compound having ester-forming functional group The polymer was dissolved in deuterated trifluoroacetic acid, and ¹ H-
Quantified by NMR.

(3) Content of diethylene glycol (DEG) The polymer was decomposed using hydrazine hydrate and quantified by gas chromatography.

(4) Crease Delamination Whitening Ratio (Delamination Resistance) A film sample is cut out to a size of 80 × 80 mm, and is gently folded in two by hand, sandwiched between a pair of flat metal plates, and then pressed by a pressing machine. Pressing was performed at a predetermined pressure P ₁ (kg / cm ² G) for 20 seconds. After pressing, the folded film sample is returned to the original state by hand, sandwiched between the metal plates, and subjected to pressure P
Pressing at ₁ (kg / cm ² G) for 20 seconds. Thereafter, the film sample was taken out, and the length (mm) of the whitened portion appearing on the fold was measured and totaled.

Using each new film sample, press pressure P ₁ = 1,2,3,4,5,6 (kg / cm
^The above measurement was repeated for 2G).

The length (m
m) is the ratio (%) of the total length of the fold (80 mm) to the fold delamination whitening ratio (%),
This value was used as an index indicating the difficulty of delamination (delamination) of the film (delamination resistance).

(5) Anti-curling property (ANSI curl value) After adjusting a film sample of 120 × 25 mm in a flat state at 23 ° C. and 50% RH for 24 hours,
The core was wound around a 7 mm diameter core in the longitudinal direction, temporarily fixed so as not to unwind, heated at 80 ° C. for 2 hours, and then released from the core. Next, the sample was immersed in distilled water at 40 ° C. for 15 minutes, and the sample was hung vertically in the longitudinal direction.
Heat drying was performed for 3 minutes in a 55 ° C. air thermostat under a load of 5 g. Samples with curls remaining
H Measured according to Test Method A of 1.29-1971,
The curl value was calculated by changing inches to a metric system and used as an index indicating anti-curl property.

(6) Young's modulus A sample film having a width of 10 mm was set on a tensile tester so that the distance between the chucks was 100 mm, and the temperature was 23 ° C. and 50% R.
Under the condition of H, a tensile test was performed at a tensile speed of 10 mm / min, and the Young's modulus in the machine direction (MD) and the transverse direction (TD) was measured.

Example 1 100 parts of dimethyl naphthalene-2,6-dicarboxylate, 60 parts of ethylene glycol and 5.4 parts of 9,9-bis [4- (2-hydroxyethoxy) phenyl] fluorene (total dicarboxylic acid) (3 mol% based on the acid component) was subjected to a transesterification reaction according to a conventional method using 0.03 parts of manganese acetate tetrahydrate as a transesterification catalyst, and then 0.023 parts of trimethyl phosphate was added to substantially add The transesterification reaction was terminated.

Further, 0.024 parts of antimony trioxide was added, and a polycondensation reaction was carried out by a conventional method under a high temperature and high vacuum to obtain a polyethylene having an intrinsic viscosity of 0.62 dl / g and a DEG copolymerization amount of 1.3 mol%. A naphthalate copolymer was obtained.

The polyethylene naphthalate copolymer pellets were dried at 180 ° C. for 3 hours, fed to an extruder popper, melted at a melting temperature of 300 ° C., and rotated and cooled at a surface temperature of 40 ° C. through a 1 mm slit die. It was extruded on a drum to obtain an unstretched film. The unstretched film thus obtained was preheated at 120 ° C., further heated by a 900 ° C. IR heater from 15 mm above between low-speed and high-speed rolls and stretched 3.0 times in the longitudinal direction. Subsequently, it was supplied to a stenter and stretched 3.3 times in the transverse direction at 140 ° C.
The obtained biaxially stretched film was heat-set at a temperature of 210 ° C. for 5 seconds to obtain a 75 μm-thick copolymerized polyethylene naphthalate film.

The obtained film was heat-treated at 110 ° C. for 2 days, and the characteristics of the film were measured. As shown in Table 1, the film was good as a base film for a photographic film.

Examples 2 to 4 A biaxially stretched film was obtained in the same manner as in Example 1 except that the amount of the fluorene compound having an ester-forming functional group was changed to the amount shown in Table 1. Table 1 shows the properties of the obtained film. As in Example 1, the film had good characteristics as a base film for a photographic film.

Comparative Example 1 A biaxially stretched film was obtained in the same manner as in Example 1 except that no fluorene compound having an ester-forming functional group was added. Table 1 shows the properties of the obtained film. A film satisfactory in delamination characteristics and curl resolving properties was not obtained.

Comparative Examples 2 and 3 The same procedure as in Example 1 was carried out except that the copolymerization amount of the fluorene compound having an ester-forming functional group was changed to the amount shown in Table 1, ie, an amount exceeding 5 mol%. A biaxially stretched film was obtained. Table 1 shows the properties of the obtained film. The delamination properties were sufficient, but the Young's modulus and curl resolving properties were insufficient.

Comparative Examples 4 and 5 A biaxially stretched film was obtained in the same manner as in Example 1 except that 2 parts of DEG was added (Comparative Example 4). D present in polyester copolymer
The copolymerization amount of EG was 4.1 mol%.

A biaxially stretched film was obtained in the same manner as in Example 1, except that the reaction was carried out at normal pressure for 25 minutes after the addition of antimony trioxide under polymerization conditions without addition of DEG. 5). The amount of DEG copolymerized in the polyester copolymer was 3.5 mol%. The DEG is produced as a by-product of the polymerization reaction and contained as a copolymer component.

When the copolymerization amount of DEG exceeds 3 mol%, the Young's modulus and curl-removing property are not good even if the same fluorene compound having an ester-forming functional group as in Example 1 is copolymerized. Was enough.

[0054]

[Table 1]

[0055]

The base film for a photographic film comprising the polyethylene naphthalate copolymer of the present invention has excellent delamination resistance, anti-curl properties, mechanical strength, good hue and transparency. For example, it can be particularly suitably used as a base film for a photographic film in a wide range of photographic applications, such as a film for photography, a roll film for still photography, a roll film for movies, a roll film for X-rays, and a film for plate making.

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-8-239459 (JP, A) JP-A-8-104742 (JP, A) JP-A-6-192408 (JP, A) (58) Field (Int. Cl. ⁷ , DB name) C08G 63/00-63/91

Claims (4)

(57) [Claims] 1. A fluorene compound having an ester-forming functional group as a copolymer component in a glycol component, comprising naphthalenedicarboxylic acid as a main acid component, ethylene glycol as a main glycol component, and 0.5% of the total acid component. A film comprising a polyethylene naphthalate copolymer containing -5 mol% and a diethylene glycol component in an amount of 3 mol% or less based on the total acid component, and having an ANSI curl value of 50 [m] at 80 ° C. ^-1 ] and a delamination resistance of not more than 10% in fold delamination whitening ratio. (2) Naphthalenedicarboxylic acid is 2,6-na
2. The photographic film according to claim 1, which is phthalenedicarboxylic acid.
Base film. (3) Thickness in the range of 25 to 250 μm
A base film for a photographic film according to claim 1. (4) Fluores with ester-forming functional groups
Compound is 9,9-bis [4- (2-hydroxyethoxy)
2. The photograph according to claim 1, which is [xy) phenyl] fluorene.
Base film for film.