JP3627190B2 - Polyester film and photographic photosensitive material - Google Patents

Description

【表２】

【表３】

【００８７】
【発明の効果】
本発明のポリエステルフィルムは、透明性、吸水性、機械的特性、耐熱性に優れており、写真感光材料の支持体またはカバー層として利用する場合、従来のＴＡＣフィルムより薄膜化が可能となり、撮影装置の小型化、巻出しの高速化等を実現することができる。[0001]
[Industrial application fields]
The present invention relates to a polyester film, and more particularly to a polyester film excellent in transparency, water absorption, and mechanical properties useful for a photographic light-sensitive material.
[0002]
[Prior art]
Photosensitive materials include those in sheet form such as X-ray film, plate making film and cut film, and roll film. A typical roll film is a color or black-and-white negative film that is stored in a cartridge with a width of 35 mm or less and is loaded into a general camera and used for photographing.
[0003]
Photosensitive materials are generally produced by coating at least one photographic photosensitive layer on a plastic film support. As the plastic film, a fiber polymer represented by triacetyl cellulose (hereinafter referred to as “TAC”) and a polyester polymer represented by polyethylene terephthalate (hereinafter referred to as “PET”) are generally used. (Fiber and Industry, 41 (9), 329-324).
[0004]
The TAC film is produced by a solution casting method using methylene chloride as a main solvent, has a small optical anisotropy, and is excellent in transparency and flatness. Further, since it has an appropriate water absorption property, it has excellent properties for decurling after development processing. In other words, curl curl occurs in the film as it rolls over time as a roll film, but the mobility of the molecular chain increases due to water absorption in the development process, and the immobilized molecular chain rearranges over time. As a result, the curl curl is eliminated.
[0005]
Photosensitive materials using a film that does not have curl curl recovery can cause scratches and defocusing when used in a roll state, for example, in a printing process that forms an image on photographic paper after development. This causes problems such as jamming during conveyance. Accordingly, TAC films have been widely used as photographic light-sensitive materials.
[0006]
However, in recent years, the use of photographic photosensitive materials has been diversified, and the film unwinding speed at the time of shooting, the development printing magnification and the slide shooting magnification have been increased, and the size of the photographing apparatus has been remarkably advanced. Therefore, the support for photographic light-sensitive materials has been required to have properties such as mechanical characteristics, dimensional stability, and thinning.
[0007]
The biaxially stretched PET film has excellent transparency, mechanical properties, and dimensional stability. For microfilms that require film thinning and printing sensitive materials that require strict dimensional stability, A PET film is used instead of the TAC film. However, in the case of a PET film, since the water absorption is small, the curl curl recovery property of the TAC film is small, so that the handleability after the development processing is poor, and the use range is limited while having the above-mentioned excellent characteristics. .
[0008]
Therefore, attempts have been made to impart water absorption to PET films by modifying PET polymers. For example, JP-A-1-244446 proposes a biaxially stretched film of a polymer obtained by copolymerizing 5-sodium sulfoisophthalic acid and adipic acid with PET. However, since the water absorption rate is inferior to that of a TAC film, sufficient winding癖 Curl recovery cannot be obtained. In addition, USP-4217441 and USP-4241170 propose a biaxially stretched film obtained by copolymerizing polyethylene glycol and 5-sodium sulfoisophthalic acid with PET, but this simply gives water vapor permeability to the film. This film is not intended for roll-shaped photographic films that require curl curl recovery, but has a certain level of water absorption, and is slightly inferior to curl curl recovery. Due to the change over time, the transparency of the film deteriorated, and further, the tensile Young's modulus at the time of water absorption decreased. JP-A-4-93937 proposes laminating a water-absorbing copolyester on the outer layer of a PET film, but this is expected to provide curl curl recovery and mechanical strength to the film. Since it is necessary to increase the copolymerization rate of the polymer in the outer layer portion, there is a problem that the crystallinity of the polymer is lowered, and the roll surface and the film stick to each other during film formation, and the total thickness of the film is If it is 80 μm or more, it is necessary to increase the thickness of the outer layer, and the productivity is greatly reduced. In addition, when the film ends other than the product are collected and the polymer is blended, and the film is formed again, the outer layer polymerWhenSince the compatibility of the core layer PET was poor, there was a problem that the transparency of the film was lowered when the film was stretched. Furthermore, there has been a problem that, during use as a photographic light-sensitive material, peeling occurs on the base film laminated surface.
[0009]
[Problems to be solved by the invention]
That is, the subject in this invention is providing the polyester film which has curling curl recovery property equivalent to a TAC film, maintaining the outstanding transparency, mechanical property, and dimensional stability.
[0010]
[Means for Solving the Problems]
The present invention has the following configuration in order to solve this problem. That is, polyesterresinConsists of at least A and B2 layersPolyester filmThe polyesters of layer A and layer B are composed of copolymers having different compositions, andA layer of polyesterA polyester in which an ester-forming monomer composed of an aromatic dicarboxylic acid having a metal sulfonate or a derivative thereof is copolymerized,B layer polyesterPolyester comprising at least one ester-forming monomer selected from aromatic dicarboxylic acids having metal sulfonates or derivatives thereof, polyethers, aliphatic dicarboxylic acids, and aliphatic polyesters as a copolymerization componentInThe tear propagation resistance is 700 g / mmthat's allAnd a photographic photosensitive material using the polyester film as a support.
[0011]
In other words, specific substances are copolymerized on a polyester film with a laminated structure to improve the affinity between polymers in each layer, thereby preventing peeling on the laminated surface and maintaining the transparency of the film when the film is collected In addition, the curl can be sufficiently recovered even in a thick film.
[0012]
In the present invention, the polyester is a polyester mainly composed of an aromatic dibasic acid and glycol, and the dibasic acid includes terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, diphenylsulfone dicarboxylic acid, Examples thereof include diphenyl ether dicarboxylic acid, diphenoxyethane dicarboxylic acid, cyclohexane dicarboxylic acid, diphenyl dicarboxylic acid, diphenyl thioether dicarboxylic acid, diphenyl ketone dicarboxylic acid, and phenylindane dicarboxylic acid. As glycols, ethylene glycol, propylene glycol, tetramethylene glycol, cyclohexanedimethanol, 2,2-bis (4-hydroxydiphenyl) propane, 2,2-bis (4-hydroxyethoxyphenyl) propane, bis (4 -Hydroxyphenyl) sulfone, diethylene glycol, neopentyl glycol, hydroquinone, cyclohexanediol and the like. Among the polyesters composed of these components, polyethylene terephthalate, polycyclohexanedimethylene terephthalate, and polyethylene naphthalate are preferable from the viewpoints of heat resistance, mechanical strength, dimensional stability, and the like.
[0013]
In the present invention,In order to impart curl curl recovery to the film, water-absorbing, and further, a component that lowers the glass transition temperature due to water absorption is copolymerized with the polymer.But,As these ingredientsAndAromatic dicarboxylic acid component, polyether, aliphatic dicarboxylic acid, aliphatic polyester with metal sulfonateIs used.
[0014]
Specific examples of the aromatic dicarboxylic acid having a metal sulfonate include 5-sodium sulfoisophthalic acid, 2-sodium sulfoterephthalic acid, 4-sodium sulfophthalic acid, 4-sodium sulfo-2,6-naphthalenedicarboxylic acid, and The compound which substituted these sodium with other metals, for example, potassium, lithium, etc. can be mentioned. Furthermore, you may substitute by ammonium salt, a phosphonium salt, etc.
[0015]
Examples of the polyether component include polyalkylene glycol and polyether dicarboxylic acid. Examples of the polyalkylene glycol include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and polyethylene glycol-polypropylene glycol copolymer. In addition, polyether dicarboxylic acid has the following formula:
R₁OOCCH₂-(O-R₂)_n-OCH₂COOR₃
(Wherein R₁, R₃: H or an alkyl group having 1 to 8 carbon atoms, R₂: An alkylene group having 2 to 8 carbon atoms, n: a positive integer. )
Polyethyleneoxydicarboxylic acid and polytetramethyleneoxydicarboxylic acid are preferred. As the polyether component, polyethylene glycol, polytetramethylene glycol, or polyethyleneoxydicarboxylic acid represented by the following formula is preferable from the viewpoint of polymerization reactivity of polyester and dimensional stability of the film.
[0016]
R₁OOCCH₂-(O-CH₂CH₂)_n-OCH₂COOR₂
(Wherein R₁, R₂: H or an alkyl group having 1 to 8 carbon atoms, n: a positive integer. )
The average molecular weight of this polyether component is 600-20000, preferably 1000-15000, more preferably 2000-10000. When the average molecular weight is 600 or less, the water absorption is insufficient and the curl curl recovery property cannot be sufficiently obtained. To obtain curl curl recovery similar to that of a TAC film, a longer polyether chain length is preferable. However, a molecular weight of 20000 or more is not preferable because the transparency and rigidity of the film are decreased.
[0017]
The aliphatic dicarboxylic acid is a dicarboxylic acid having an alkylene group having 4 to 60 carbon atoms, preferably adipic acid, sebacic acid, eicoic acid, dodecanedioic acid, dimer acid, and more preferably adipic acid, sebacic acid, dimer acid. preferable.
[0018]
Examples of the aliphatic polyester include poly ε-caprolactone, poly (methyl-ε-caprolactone), and poly β-propiolactone, and the molecular weight is preferably about 800 to 40000, more preferably 2000 to 20000.
[0019]
Also, copolymerization of polyolefins such as polyethylene, polypropylene, and ethylene / propylene copolymers that have been modified to form esters as long-chain components can improve curl curl recovery and tensile Young's modulus during water absorption. it can. The average molecular weight after modification is preferably 500 to 10,000.
[0020]
The present inventionNoSteal-forming monomerー andIs a substance listed in each of the aromatic dicarboxylic acid component, polyether, aliphatic dicarboxylic acid, aliphatic polyester and the like having the above-described metal sulfonate, for example. In the case of an aromatic dicarboxylic acid having a metal sulfonate, the metal part may be substituted with other components, and in the case of a polyether or aliphatic polyester, the main chain part may be copolymerized or the terminal part. May be modified with a carboxylic acid or a hydroxy group.
[0022]
It consists of at least A and B2 layers according to the present invention.Polyester filmInThe polyester of the A layer and the B layer is composed of copolymers having different compositions, and the polyester of the A layer isPolyester copolymerized with ester-forming monomer comprising aromatic dicarboxylic acid having metal sulfonate or derivative thereofAnd B layer polyesterPolyester having at least one ester-forming monomer selected from an aromatic dicarboxylic acid having a metal sulfonate or a derivative thereof, polyether, aliphatic dicarboxylic acid, or aliphatic polyester as a copolymerization componentLeis there. These water-absorbing components or glass transition temperature lowering components may be copolymerized with only one component, but may be copolymerized with a combination of two or more components.IsPreferably it is 3 to 15 weight% with respect to polyester, More preferably, it is 3 to 10 weight%.
[0023]
Components that are commonly copolymerized in a plurality of laminated polyesters include components for imparting curl curl recovery properties such as aromatic dicarboxylic acid components, polyethers, aliphatic dicarboxylic acids, and aliphatic polyesters having metal sulfonates. However, since high molecular weight components such as polyether and aliphatic polyester are low in copolymerization molar ratio, the effect is small from the viewpoint of improving the affinity between the respective layer polymers. In contrast, relatively low molecular weight components such as aromatic dicarboxylic acid components and aliphatic dicarboxylic acids having metal sulfonates have a high copolymerization molar ratio and thus greatly affect the affinity of the polymer. The copolymerization rate is affected by copolymerization of 1% by weight or more with respect to the reaction product polyester.
[0025]
Polyester for the total thickness of the polyester filmthe filmThe thickness ratio of each layer is y (%), and the y value is 5% or more.As a resin componentIn the layer, the reaction productIsEster-forming monomers for polyester.ーWhen the maximum value of the copolymerization rate x (% by weight) is z, the x value of each layer is z / 20 ≦ x ≦ z, preferably z / 10 ≦ x ≦ z, and more preferably z / 5 ≦ x. ≦ z.
[0026]
In other words, when copolymerizing, the copolymerization ratio of copolymer monomers with similar structures must be as close to each layer as possible, and if a layer with little copolymerization is provided, the lamination thickness should be as thin as possible. It is necessary.
[0027]
A great feature of the polyester film of the present invention is that it has a multilayer structure. The polyester film of the present invention may have an A / B two-layer structure or a B / A / B three-layer structure. If the polyester layer other than A and B is a C layer, a structure such as B / A / C may be used, and a multilayer structure such as C / B / A / B / C may be used. In any case, a common copolymerization component is necessary for each polyester layer having a y value of 5% or more, but the ratio of the copolymerization monomer that causes the above-mentioned water absorption in the B layer and further the glass transition temperature decrease due to water absorption. Is preferably greater than or equal to the ratio of the A layer.
[0028]
The polyester of the B layer is copolymerized with water-absorbing and glass transition temperature lowering components, so that a low polymer is easily deposited on the film surface due to thermal history. Therefore, when the film lamination structure is an A / B structure, it is particularly effective for preventing the precipitation of low molecular weight substances on one side of the film. Furthermore, the curl curl curl of the film can be efficiently recovered by the difference in water absorption between the A layer and the B layer.
[0029]
Next, the B / A / B configuration will be described. That is, the B layer may be laminated on both sides of the A layer. At that time, the B layer having a large water absorption has functions such as curling curl recovery and the A layer having a small water absorption has functions such as mechanical strength and dimensional stability. That is why. However, low molecular weight substances such as oligomers may remain in the B layer polyester. To prevent this, the B layer polyester may be solid-phase polymerized to reduce the low polymer, and further on the outside of the A layer. A C layer may be provided to prevent precipitation of low molecular weight substances. That is, for example, a five-layer structure of C / B / A / B / C may be used. As the polyester of the C layer, the same polyester as that of the A layer is preferably used, but it is desired that the amount of the low polymer is small, and the thickness of the laminated layer needs to be thin within a range in which the precipitation of the low polymer can be suppressed. .
[0030]
In the case of the B / A / C configuration, the C layer may use a polyester that hardly absorbs water and has a high glass transition temperature, and conversely, a polyester that imparts water absorption similar to or higher than that of the B layer. May be. In the former case, the film is less likely to curl and the transportability of the film in the development process is improved. In the latter case, the mechanical strength of the film is based on the A layer, and the curl curl recoverability can be adjusted by the difference in water absorption between the B layer and the C layer.
[0031]
In the present invention, a film having a laminated structure of B / A / B or C / B / A / B / C having an A layer in the core layer is particularly preferable.
[0032]
In order to improve the tensile Young's modulus at the time of water absorption, it is preferable to copolymerize a rigid component with the polyester of the A layer. As rigid components, 4,4′-diphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid, diphenylether-4,4′-dicarboxylic acid, diphenoxyethane-4,4′-dicarboxylic acid, diphenoxybutane-4, 4'-dicarboxylic acid, diphenylethane-4,4'-dicarboxylic acid, diphenyl ether-4,4'-dicarboxylic acid, 4,3'-diphenyldicarboxylic acid, diphenyl ether-3,3'-dicarboxylic acid, diphenoxyethane- 3,3′-dicarboxylic acid, diphenylethane-3,3′-dicarboxylic acid, naphthalene-1,6′-dicarboxylic acid, hydroquinone, 4,4′-dioxydiphenyl, 2,6-naphthalenediol, 4,4 '-Dioxydiphenyl ether, bis (4-oxyphenoxy) ethane, 3,3'-dioxy Diphenyl, phenyl hydroquinone, 4-hydroxybenzoic acid, 3-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, 6-hydroxy-1-naphthoic acid. Although these rigid components may be copolymerized singly or in plural, the copolymerization ratio is 0 to 40% by weight, preferably 0 to 30% by weight, more preferably 0 to 20% with respect to the polyester of the reaction product. % By weight.
[0033]
In order to improve the water absorption rate of the polyester film of the present invention, the polyester of the A layer and the B layer may be, for example, a single-end-capped polyether compound as long as it is a small proportion that does not impair transparency and mechanical properties. You may add water absorption promoters, such as. The one-end blocked polyether compound is represented by the following formula, for example.
[0034]
HOOCCH₂O (CH₂CH₂O)_nR₄
HO (CH₂CH₂O)_nR₄
HO (CH₃CHCH₂O)_nR₄
(Where R₄Is an alkyl group having 1 to 5 carbon atoms, and n is 30 to 500. )
The preferred molecular weight is 600-20000. Moreover, the addition amount of these water absorption accelerators is preferably 0 to 15% by weight with respect to the polyester component.
[0035]
The glass transition temperature of the polyester A layer is 60 ° C. or higher, preferably 65 ° C. or higher, more preferably 70 ° C. or higher. The glass transition temperature when immersed in water at 24 ° C. for 30 minutes is 45 ° C. or higher, preferably 55 ° C. or higher, more preferably 65 ° C. or higher. When the normal glass transition temperature is less than 60 ° C. or the glass transition temperature at the time of water absorption is less than 45 ° C., the strength of the film is greatly reduced, and the dimensional stability is extremely deteriorated.
[0036]
The glass transition temperature of the polyester B layer is 45 ° C to 75 ° C, preferably 50 ° C to 70 ° C, more preferably 55 ° C to 70 ° C or higher. Moreover, the glass transition temperature when immersed in water at 24 ° C. for 30 minutes is 30 ° C. to 60 ° C., preferably 35 ° C. to 55 ° C., more preferably 35 ° C. to 50 ° C. or more. If the glass transition temperature is too low, the strength of the film is greatly reduced, and if the glass transition temperature is too high, curl curl recovery is reduced.
[0037]
In the present invention, the thickness of the A layer is not particularly limited, but the thickness of the A layer is preferably in the range of 1 to 99% with respect to the total thickness of the polyester film.
[0038]
In the case of performing multi-layer lamination, specific examples of this means include a co-extrusion method using a plurality of extruders and field blocks or a multi-manifold die.
[0039]
The haze value of the polyester film of the present invention is 3% or less, preferably 2% or less. If the haze value exceeds 3%, it becomes an obstacle in applications where transparency is required. In the case of a general copolymerized polyester film, the low polymer tends to remain in the film as described above, and the low polymer tends to bleed out to the surface over time, thereby impairing transparency. One of the features of the present invention is that the decrease in transparency due to the precipitation of the low polymer is small. For example, the haze value of the polyester film of the present invention is preferably 10% or less even when left for 2 weeks in an atmosphere of 40 ° C. and 90% RH.
[0040]
The polyester film according to the present invention can be imparted with slipperiness depending on the application, and there is no particular limitation on the slipperiness imparting means, but the inert inorganic compound, organic crosslinked particles Kneading or application of a surfactant is used as a general method.
[0041]
Such inert inorganic particles include SiO 2₂TiO₂, BaSO₄, CaCO₂, Talc, kaolin and the like. In addition to providing lubricity by external particle system that adds inert particles to the above polyester synthesis reaction system, it is also possible to adopt a lubricity imparting method by internal particle system that deposits a catalyst added during the polymerization reaction of polyester. It is.
[0042]
These slipperiness imparting means are not particularly limited, but in applications where transparency is an important requirement, the slipperiness imparting method has a refractive index relatively close to that of the polyester film as the external particle system. SiO₂Alternatively, it is desirable to select an internal particle system capable of relatively reducing the particle size of the precipitated particles. These particle systems may be added to any layer of the polyester film of the present invention, but are preferably added to the surface layer.
[0043]
Photographic films are used even in harsh conditions such as in a car in the summer, in the tropics, and in the desert. At that time, if the dimensional change of the film becomes large, there arises a problem that the image is deformed. While the thermal shrinkage rate of TAC film and PET film is as small as 0.2% or less, the thermal shrinkage rate of copolymerized polyester film generally tends to increase, but the thermal shrinkage rate of the copolymerized polyester film of the present invention. One of the major features is that the rate is less than that of PET film. The polyester film of the present invention preferably has a heat shrinkage rate of 80% at 6 ° C of 0.4% or less, more preferably 0.3% or less.
[0044]
Further, the tear propagation resistance of the polyester film of the present inventionIs 700 g / mm or more,Preferably it is 800 g / mm or more.
[0045]
The breaking strength of the polyester film of the present invention is 8 kg / mm.²Or more, more preferably 13 kg / mm²That's it. Furthermore, the tensile Young's modulus is 300 kg / mm²Or more, preferably 350 kg / mm²That's it. The tensile Young's modulus when the polyester film is immersed in distilled water at 24 ° C. for 30 minutes is 260 kg / mm.²Or more, preferably 280 kg / mm²That's it. When the mechanical strength is reduced, when the film is used as a support for a photographic material, for example, the film may be easily deformed or broken by external force during winding in a camera, automatic development by a machine, or baking. There is.
[0046]
The method for synthesizing the raw material polymer of the copolymerized polyester film of the present invention can be produced according to a conventionally known polyester production method. For example, the acid component is directly esterified with the glycol component, or when a dialkyl ester is used as the acid component, the ester component is transesterified with the glycol component, and this is heated under reduced pressure to remove excess glycol component. A copolyester can be obtained. At this time, if necessary, a transesterification catalyst or a polymerization reaction catalyst can be used, or a heat-resistant stabilizer can be added. Of course, for practical purposes, coloring agents, antioxidants, crystal nucleating agents, slipping agents, stabilizers, antiblocking agents, UV absorbers, viscosity modifiers, antifoaming agents, clearing agents, antistatic agents, etc. are added. Also good.
[0047]
The copolyester obtained above is generally shaped into granules, dried and melted, and coextruded from a T-die to form an unstretched film. When the molten polyester film is brought into contact with the cooling roll, it is preferable to apply an electrostatic application cooling method.
[0048]
In order to impart mechanical strength to the film, the unstretched film extruded from the T die is preferably further biaxially stretched. In the case of biaxial stretching, a sequential biaxial stretching method or a simultaneous biaxial stretching method can be used, but a sequential biaxial stretching method in which stretching in the longitudinal direction first and then in the width direction is preferred.
[0049]
The stretching temperature is preferably in the range of the glass transition temperature to the cold crystallization temperature. In the present invention, it is desirable that the stretching temperature is 60 to 140 ° C. in the longitudinal direction and 70 to 150 ° C. in the width direction. A stretching ratio of 2.0 to 5.0 is usually appropriate. In order to increase the strength of the film, it is better to increase the draw ratio within a range in which the film forming property does not deteriorate, preferably 3.5 times or more, more preferably 4.0 times or more. In order to increase the tensile Young's modulus at the time of water absorption, a so-called multi-stage longitudinal stretching method may be performed in which stretching is performed at a high temperature at the time of longitudinal stretching and then at a low temperature. Further, after the longitudinal and lateral stretching, it may be re-stretched in either the longitudinal or lateral direction.
[0050]
In order to improve the tear propagation resistance of the film, it is desirable to balance the longitudinal direction and the transverse direction by increasing the draw ratio, preferably 3.4 times or more, more preferably 3.8 times or more, The difference between the draw ratios in the direction and the transverse direction is preferably 0.7 or less, and more preferably 0.5 or less.
[0051]
Furthermore, you may heat-process the stretched film. The heat treatment condition in this case may be any of a constant length, a relaxed state, and a finely stretched state. In the case of the polyester film of the present invention, it is 150 to 225 ° C., preferably 170 to 220 ° C. and 0.5 to 60. Seconds are preferred. In particular, in the case of the present invention, it is preferable that the heat treatment temperature is high within a range in which the film-forming property does not deteriorate. Specifically, when the polyester is measured with a differential scanning calorimeter, heat treatment is preferably performed in the vicinity of a temperature at which the endothermic peak appearing with crystal melting starts to deviate from the baseline. The heat treatment state is confirmed by measuring the obtained polyester film with a differential scanning calorimeter, and is originally observed as a shoulder portion of the crystal melting peak of polyester or another peak. By increasing this heat treatment peak, the amorphous part orientation of the polyester is relaxed, the heat shrinkage rate at high temperature, for example, the heat shrinkage rate at 150 ° C. is decreased, and further, water absorption, for example, water vapor permeability and water absorption rate is increased. Increase.
[0052]
Particularly in the case of the polyester film of the present invention, the tensile Young's modulus, the breaking strength, and the tear propagation resistance can be improved in a well-balanced manner by performing heat treatment at a high temperature after stretching at a high magnification, and also has a low heat shrinkage and a water absorption rate. As a result, the curl curl recovery property is also improved.
[0053]
Although it does not specifically limit as thickness of the polyester film of this invention, In the case of a stretched film, the thing of 3-360 micrometers is preferable in the case of an unstretched film, and 50-2000 micrometers. In the field of application of photographic film, a thickness of 25 to 250 μm is preferable, and a thickness of 40 to 150 μm is more preferable.
[0054]
The wetting tension of the surface of the polyester film of the present invention is 50 dyne / cm or more, preferably 54 dyne / cm or more. Moreover, in order to improve adhesiveness and the wettability of the coating liquid, various surface treatments such as corona discharge treatment, chemical treatment, flame treatment, ultraviolet treatment, and plasma treatment can be applied to the film as necessary. In the present invention, corona discharge treatment is preferred.
[0055]
The polyester film of the present invention can be used for various transparent films such as OHP films and optical films by utilizing its excellent transparency, thermal dimensional stability and mechanical properties in addition to the support or cover layer of photographic photosensitive materials. It can be used for packaging film for fresh food, magnetic recording tape, magnetic floppy film, and the like.
[0056]
[Methods for measuring physical properties and methods for evaluating effects]
The characteristic values of the present invention are based on the following measurement methods and evaluation criteria.
[0057]
(1) Glass transition temperature
A polyester film or 10 mg of polyester film is set in a differential scanning calorimeter, the temperature is increased at a rate of 20 ° C./min under a nitrogen stream, the temperature at which the baseline begins to deviate, and the temperature at which the baseline returns to the new baseline Was the glass transition temperature. The glass transition temperature at the time of water absorption was measured by immediately setting a film that was immersed in distilled water at 24 ° C. for 30 minutes to absorb water and then setting the film on a differential scanning calorimeter.
[0058]
(2) Film haze
Film haze was measured according to ASTM-D1003-52.
[0059]
(3) Thermal contraction rate
Film samples having a width of 10 mm and a length of 250 to 300 mm were marked at intervals of 200 mm, fixed to a sample support plate under a constant tension, and the original length of the marking interval was measured using a universal projector (V16A manufactured by Nippon Optical Co., Ltd.). A load was applied to the measured sample using a 3 g clip, and the sample was processed while rotating in a hot air oven set at 80 ° C. for 6 hours. The treated sample was allowed to stand in the atmosphere where the original length was measured for 2 hours, and then the marking interval was measured in the same manner as the original length measuring method to obtain the shrinkage rate.
[0060]
(4) Tear propagation resistance
It measured according to ASTM-D-1922 using a light load type tear tester (manufactured by Toyo Seiki Co., Ltd.). The sample size was 51 × 64 mm with a 13 mm cut, and the indicated value was read when the remaining 51 mm was torn.
[0061]
(5) Breaking strength, tensile Young's modulus
According to JIS-Z1702-1976, a strip having a width of 10 mm and a length of 100 mm, the tensile speed was measured at 300 mm / min when measuring the breaking strength, and the tensile Young's modulus was measured at 20 mm / min. The tensile Young's modulus at the time of water absorption was measured by immediately immersing it in distilled water at 24 ° C. for 30 minutes as a strip.
[0062]
(6) Intrinsic viscosity
It measured at 25 degreeC using the o-chlorophenol solvent.
[0063]
(7) Curling curl recovery
A polyester film is sampled in a size of 35 mm in the horizontal direction and 135 mm in the longitudinal direction, wound on a core with a diameter of 10 mm, treated at 70 ° C., 30% RH, 72 hours, then released from the core and distilled water at 38 ° C. For 30 minutes, and then dried in a hot air oven at 50 ° C. for 5 minutes under a tension of 30 g. The diameter of the cylinder formed when the treated film sample was placed on a flat surface was measured. The curl curl recoverability was evaluated in the following five stages. In evaluations 4-5, it can be used for photography, but in evaluations 1-3, it cannot be used.
[0064]
5: The film did not curl and became flat
4: Cylindrical diameter is 60mm or more
3: The diameter of the cylinder is 40-60 mm
2: The diameter of the cylinder is 20 to 40 mm
1: The diameter of the cylinder is less than 20 mm
(8) Collection test
A mixture of polymer chips corresponding to each polyester lamination ratio was mixed by 20% by weight with respect to the original core layer polymer chip to perform extrusion film formation, and the haze of the film was measured.
[0065]
(9) Lamination interface peelability
100 squares with a side of 1 mm were made on the film surface using a single blade, and a cellophane adhesive tape peeling test was conducted. Out of the squares, the number of peeled pieces was less than 20, ◎, 20 to 40 were marked with ◯, and 40 or more were marked with x.
[0066]
【Example】
Next, the present invention will be described in more detail with reference to examples.
[0067]
Example 1
To 100 parts by weight of dimethyl terephthalate, 70 parts by weight of ethylene glycol, 5 parts by weight of dimethyl 5-sodium sulfoisophthalate, 0.1 parts by weight of calcium acetate and 0.03 parts by weight of antimony trioxide are added, and the ester exchange reaction is carried out by a conventional method. Was done. To the obtained product, 0.05 part by weight of trimethyl phosphate is added, gradually heated and depressurized, and finally polymerized at 280 ° C. and 1 mmHg or less, and a copolyester having an intrinsic viscosity of IV = 0.65. A was created.
[0068]
100 parts by weight of dimethyl terephthalate, 70 parts by weight of ethylene glycol, 8 parts by weight of dimethyl 5-sodium sulfoisophthalate, 10 parts by weight of polyethylene glycol having an average molecular weight of 4000, 0.1 part by weight of calcium acetate and 0.03 part by weight of antimony trioxide The copolymer polyester B having an intrinsic viscosity IV = 0.85 was obtained in the same manner as the polyester A.
[0069]
After drying the polyester in a conventional manner, a biaxially stretched film forming machine equipped with two extruders and a die capable of two-layer melt coextrusion is used. Polyester A is used in one extruder and the other extruder is used. Polyester B was provided and melted at 280 ° C., and two layers of A / B were coextruded to prepare an unstretched film. Subsequently, the film was sequentially stretched 3.5 times in the longitudinal direction at 85 ° C. and 3.5 times in the transverse direction at 90 ° C., and then heat-fixed at 215 ° C. for 5 seconds to obtain a biaxially stretched film having a thickness of 100 μm. The thickness of A / B was 65 μm / 35 μm.
[0070]
Example 2
Using the same polyesters A and B as in Example 1, after drying in a conventional manner, one extruder using a biaxially stretched film forming machine equipped with two extruders and a die capable of three-layer melt coextrusion. Polyester A and polyester B in the other extruder were melted at 280 ° C., and three layers of B / A / B were coextruded to prepare an unstretched film. Subsequently, the film was sequentially stretched 3.5 times in the longitudinal direction at 85 ° C. and 3.5 times in the transverse direction at 90 ° C., and then heat-fixed at 215 ° C. for 5 seconds to obtain a biaxially stretched film having a thickness of 100 μm. The thickness of B / A / B was 20 μm / 60 μm / 20 μm.
[0071]
Example 3
Polyester A having an intrinsic viscosity of IV = 0.75 using 100 parts by weight of dimethyl terephthalate, 70 parts by weight of ethylene glycol, 3 parts by weight of dimethyl 5-sodium sulfoisophthalate, and 5 parts by weight of dimethyl dimer as in Example 1. It was created.
[0072]
Further, in the same manner as in Example 1 using 100 parts by weight of dimethyl terephthalate, 70 parts by weight of ethylene glycol, 8 parts by weight of dimethyl 5-lithium sulfoisophthalate, and 10 parts by weight of polyethylene glycol having an average molecular weight of 4000, the intrinsic viscosity IV = A 0.75 polyester B was prepared.
[0073]
In the same manner as in Example 2, three layers of B / A / B were coextruded to produce an unstretched film. Next, the film was successively stretched 3.5 times in the longitudinal direction at 80 ° C. and 3.5 times in the transverse direction at 90 ° C., and then heat-fixed at 205 ° C. for 5 seconds to obtain a biaxially stretched film having a thickness of 100 μm. The thickness of B / A / B was 15 μm / 70 μm / 15 μm.
[0074]
Example 4
It was prepared in the same manner as in Example 1 using 100 parts by weight of dimethyl terephthalate, 70 parts by weight of ethylene glycol, 3 parts by weight of dimethyl 5-sodium sulfoisophthalate, and 3 parts by weight of polyethyleneoxydicarboxylic acid having an average molecular weight of 4000. Polyester A with IV = 0.85 was obtained.
[0075]
It was prepared in the same manner as in Example 1 using 100 parts by weight of dimethyl terephthalate, 70 parts by weight of ethylene glycol, 6 parts by weight of dimethyl 5-sodium sulfoisophthalate, and 8 parts by weight of polyethyleneoxydicarboxylic acid having an average molecular weight of 4000. = 0.75 polyester B was obtained.
[0076]
In the same manner as in Example 2, three layers of B / A / B were coextruded to produce an unstretched film. Subsequently, the film was sequentially stretched 3.5 times in the longitudinal direction at 85 ° C. and 3.5 times in the transverse direction at 90 ° C., and then heat-fixed at 215 ° C. for 5 seconds to obtain a biaxially stretched film having a thickness of 100 μm. The thickness of B / A / B was 15 μm / 70 μm / 15 μm.
[0077]
Example 5
It was prepared in the same manner as in Example 1 using 100 parts by weight of dimethyl terephthalate, 70 parts by weight of ethylene glycol, and 5 parts by weight of dimethyl dimer to obtain polyester A having an intrinsic viscosity IV = 0.85.
[0078]
Prepared in the same manner as in Example 1 using 100 parts by weight of dimethyl terephthalate, 70 parts by weight of ethylene glycol, 6 parts by weight of dimethyl 5-sodium sulfoisophthalate, 5 parts by weight of polyethylene glycol having an average molecular weight of 4000, and 5 parts by weight of dimethyl adipate. As a result, polyester B having an intrinsic viscosity IV of 0.75 was obtained.
[0079]
In the same manner as in Example 2, three layers of B / A / B were coextruded to produce an unstretched film. Next, the film was successively stretched 3.5 times in the longitudinal direction at 85 ° C. and 3.5 times in the transverse direction at 90 ° C., and then heat-fixed at 205 ° C. for 5 seconds to obtain a biaxially stretched film having a thickness of 100 μm. The thickness of B / A / B was 25 μm / 50 μm / 25 μm.
[0080]
Comparative Example 1
Polyethylene terephthalate having an intrinsic viscosity of IV = 0.65 is prepared by a conventional method, and further formed into a film, which is successively stretched 3.5 times in the longitudinal direction at 90 ° C. and 3.5 times in the transverse direction at 95 ° C., and then at 220 ° C. The film was heat-fixed for 5 seconds to obtain a biaxially stretched film having a thickness of 100 μm.
[0081]
Comparative Example 2
100 parts by weight of dimethyl terephthalate, 70 parts by weight of ethylene glycol, 10 parts by weight of dimethyl 5-sodium sulfoisophthalate, 10 parts by weight of polyethylene glycol having an average molecular weight of 4000, 0.1 part by weight of calcium acetate and 0.03 part by weight of antimony trioxide Part to make a copolyester having an intrinsic viscosity of IV = 0.80, further filmed, stretched 3.3 times in the machine direction at 85 ° C and 3.5 times in the transverse direction at 90 ° C, The film was heat-set at 180 ° C. for 5 seconds to obtain a biaxially stretched film having a thickness of 100 μm.
[0082]
Comparative Example 3
To 100 parts by weight of dimethyl terephthalate, 70 parts by weight of ethylene glycol, 10 parts by weight of dimethyl 5-sodium sulfoisophthalate, and 10 parts by weight of dimethyl adipate, 0.1 part by weight of calcium acetate and 0.03 part by weight of antimony trioxide are added. Then, a copolyester having an intrinsic viscosity of IV = 0.80 is prepared, and further formed into a film, which is successively stretched 3.6 times in the machine direction at 85 ° C. and 3.8 times in the transverse direction at 90 ° C., and then at 200 ° C. The film was heat-fixed for 5 seconds to obtain a biaxially stretched film having a thickness of 100 μm.
[0083]
Comparative Example 4
Polyethylene terephthalate having an intrinsic viscosity IV = 0.68 was designated as polyester A. Further, it was prepared in the same manner as in Example 1 using 100 parts by weight of dimethyl terephthalate, 70 parts by weight of ethylene glycol, 20 parts by weight of dimethyl 5-sodium sulfoisophthalate, and 10 parts by weight of dimethyl adipate, and an intrinsic viscosity IV = 0.65. Polyester B was obtained.
[0084]
In the same manner as in Example 2, three layers of B / A / B were coextruded to produce an unstretched film. Next, the film was successively stretched 3.5 times in the longitudinal direction at 90 ° C. and 3.5 times in the transverse direction at 95 ° C., and then heat-fixed at 210 ° C. for 5 seconds to obtain a biaxially stretched film having a thickness of 100 μm. The thickness of B / A / B was 30 μm / 40 μm / 30 μm. However, the film was easy to stick to the heat-treated tenter clip during film formation, and film tearing frequently occurred.
[0085]
Tables 1, 2 and 3 show physical properties of Examples 1 to 5, Comparative Examples 1 to 4 and the TAC film. In Examples, a film useful as a photographic light-sensitive material having excellent curl curl recovery, mechanical properties, transparency and the like was obtained. Comparative Example 4 was excellent in curl curl recovery and mechanical properties, but was poor in productivity and easily peeled off at the lamination interface, and had a problem in recoverability.
[0086]
[Table 1]

[Table 2]

[Table 3]

[0087]
【The invention's effect】
The polyester film of the present invention is excellent in transparency, water absorption, mechanical properties, and heat resistance. When used as a support or cover layer of a photographic photosensitive material, the polyester film can be made thinner than a conventional TAC film, and photography is possible. It is possible to realize downsizing of the apparatus and high speed of unwinding.

Claims (4)

An aromatic dicarboxylic acid comprising a polyester film comprising at least A and B layers containing polyester as a resin component, wherein the polyesters in layers A and B are composed of copolymers having different compositions, and the polyester in layer A has a metal sulfonate Alternatively, an ester-forming monomer composed of a derivative thereof is a polyester copolymerized, and the polyester of B layer is an ester selected from an aromatic dicarboxylic acid having a metal sulfonate or a derivative thereof, a polyether, an aliphatic dicarboxylic acid, and an aliphatic polyester. Ru polyester der to at least one copolymerization component forming monomer, polyester film, wherein the tear propagation resistance of 700 g / mm or more. The thickness ratio of each layer of the polyester film to the total thickness of the polyester film and y (%), in a layer y value is more than 5% of the polyester resin component, a co-ester-forming monomer over to polyester is the reaction product When z is the largest value of the polymerization rate x (% by weight), the x value of each layer is z / 20 ≦ x ≦ z.
Polyester film of claim 1 Symbol mounting, characterized in that a. 3. The polyester film according to claim 1 , wherein the polyester film has a laminated structure composed of at least two layers formed by a coextrusion method. Photographic material as support the polyester film according to any one of claims 1 to 3, characterized by comprising at least one layer photosensitive layer of on the polyester film.