JP2017065114A - Laminated film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated film which has sufficiently excellent adhesiveness to a coat layer such as a hard coat layer, suppresses precipitation of an oligomer from the coat layer during heat treatment, and can keep excellent adhesiveness even when used under high temperature environment for a long period of time.SOLUTION: There is provided a polyester laminated film which is a laminated film that has a resin layer on at least one surface of a polyester film base material, where the resin layer contains 0.1-30 pts.mass of a curing agent with respect to 100 pts.mass of a polyester resin, and 5 mol% or more and less than 70 mol% of a diol component of a polyester resin constituting the resin layer is a diol component having a tricyclodecane structure.SELECTED DRAWING: None

Description

  The present invention relates to a laminated film suitable for electronic materials and the like.

  Biaxially oriented polyester films are used as substrates in various fields such as optical applications because of their excellent stability and mechanical and electrical properties. Various coat layers are provided for imparting functionality.

  Since a polyester film generally has low adhesion to a coat layer, an adhesive property modification layer (also referred to as an easy adhesion layer) is provided between the polyester film substrate and the coat layer.

  For example, Patent Document 1 discloses a polyester film provided with an easy adhesion layer containing an acrylic resin or a polyester resin.

  In recent years, due to diversification of uses of polyester films, the processing conditions and the use environment have been increased in temperature, and accordingly, oligomers contained in the polyester film of the substrate may be precipitated. In this case, problems such as a decrease in transparency of the film due to the precipitated oligomer, contamination of the line, and a decrease in adhesiveness occur. In addition, when used in a high temperature environment for a long period of time, there is a possibility that the adhesiveness may deteriorate with time and become a serious defect.

  In order to solve the above problems, studies have been made to laminate an oligomer prevention layer on a polyester film (Patent Document 2).

  Moreover, the laminated polyester film of 3 or more layers which reduced the amount of oligomers in a film base material by forming into a film using the polyester resin by which the solid state polymerization process was carried out is also known conventionally (patent document 3).

  On the other hand, using an aqueous polyester resin dispersion containing specific amounts of aromatic dicarboxylic acid and tricyclodecane dimethanol as the acid component and alcohol component constituting the polyester resin, adhesion, transparency, water resistance, A technique for forming a resin film excellent in performance such as solvent resistance and heat resistance is disclosed (Patent Document 4). Also, a copolyester resin comprising a dicarboxylic acid component containing a specific amount of aromatic dicarboxylic acid and a glycol component containing a specific amount of tricyclodecane dimethanol, having a glass transition temperature of more than 30 ° C. and 70 ° C. or less. A technique for improving the hot adhesiveness and wet heat durability by using is disclosed (Patent Document 5).

JP 2010-76439 A JP 2012-92314 A JP 2000-141570 A JP 2011-137086 A Japanese Patent No. 5466095

  However, the oligomer prevention layer disclosed in Patent Document 2 was not sufficient in the effect of suppressing oligomer precipitation.

  Further, as disclosed in Patent Document 3, a method using a polyester resin obtained by subjecting a polyester film to solid phase polymerization treatment is difficult to employ because of its high cost.

  Furthermore, when the resin film was formed using the polyester resin aqueous dispersion described in Patent Document 4 between the polyester film and a coat layer such as a hard coat layer, the adhesion of the coat layer was not sufficient. When the polyester resin described in Patent Document 5 is applied to a film as an adhesive and laminated, the blocking resistance is not sufficient, and it may not be formed into a roll.

  The present invention is intended to solve the above problem, and when a coat layer such as a hard coat layer is formed on a resin film, it has excellent adhesion to the coat layer, and oligomer precipitation occurs during heat treatment. The present invention provides a polyester-based laminated film that is suppressed and can maintain the initial adhesiveness even when used for a long time in a high-temperature environment.

  As a result of intensive studies to solve the above problems, the present inventors have achieved the above object by providing a polyester layer having a specific monomer structure and a resin layer containing a curing agent on a polyester film substrate. The present invention was reached.

That is, the gist of the present invention is as follows.
(1) A laminated film having a resin layer on at least one side of a polyester film substrate, wherein the resin layer contains 0.1 to 30 parts by mass of a curing agent with respect to 100 parts by mass of a polyester resin, and the resin layer is A polyester-based laminated film, wherein a diol component having a tricyclodecane structure is comprised of 5 mol% or more and less than 70 mol% of a diol component of a polyester resin constituting the polyester resin.
(2) The curing agent is one or more curing agents selected from the group consisting of a polyfunctional isocyanate compound, a carbodiimide group-containing compound, an oxazoline group-containing compound, and a melamine resin, (1) The polyester-type laminated film as described in.
(3) After applying a coating liquid containing a polyester resin and a curing agent on at least one surface of the polyester base material, a heat drying treatment is performed at a temperature of 180 ° C. or higher. (1) or (2) The manufacturing method of the polyester-type laminated | multilayer film of description.
(4) The method for producing a polyester-based laminated film according to (3), wherein the polyester film substrate coated with the coating liquid is stretched in at least one direction.

  ADVANTAGE OF THE INVENTION According to this invention, while being excellent in adhesiveness with various coating layers, the polyester-type laminated | multilayer film with which precipitation of the oligomer from a base polyester film was reduced can be provided. Since the polyester-based laminated film of the present invention can suppress the precipitation of oligomers from the substrate surface during heat treatment, the contamination of the line and the decrease in transparency of the film are suppressed. Therefore, even when incorporated as a member in a touch panel, a smartphone, or the like, the resolution of the optical element is not impaired, and excellent adhesion with various coat layers can be maintained even when used for a long time in a high temperature environment.

  The polyester-based laminated film of the present invention has a polyester resin containing a diol component having a tricyclodecane structure and a resin layer containing a curing agent on the surface of the polyester film substrate.

  Although it does not specifically limit as a polyester resin used for a polyester film base material, For example, a polyethylene terephthalate, a polybutylene terephthalate, polyethylene-2,6-naphthalate is mentioned. You may copolymerize another component with a polyester resin as needed.

  Examples of other components include a carboxylic acid component, a hydroxycarboxylic acid component, and an alcohol component. Examples of the carboxylic acid component include isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 5-sodium sulfoisophthalic acid, oxalic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, dodecanedioic acid, dimer acid , Maleic anhydride, maleic acid, fumaric acid, itaconic acid, citraconic acid, mesaconic acid, cyclohexanedicarboxylic acid, trimellitic acid, trimesic acid, and pyromellitic acid. Examples of the hydroxycarboxylic acid component include 4-hydroxybenzoic acid, ε-caprolactone, and lactic acid. Examples of the alcohol component include ethylene glycol, diethylene glycol, 1,3-propanediol, neopentyl glycol, 1,6-hexanediol, cyclohexanedimethanol, triethylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and bisphenol. Examples include ethylene oxide adducts of A and bisphenol S, trimethylolpropane, glycerin, and pentaerythritol. Two or more of these copolymer components may be used in combination.

  The melting point of the polyester resin for the substrate is preferably 230 ° C. or higher from the viewpoint of imparting heat resistance.

  Examples of the method for polymerizing the polyester resin for the substrate include known production methods such as a direct esterification method and a transesterification method. Examples of the direct esterification method include a method in which a necessary monomer raw material is injected into a reaction vessel, an esterification reaction is performed, and then a polycondensation reaction is performed. In the esterification reaction, the reaction is performed by heating and melting at a temperature of 160 ° C. or higher for 4 hours or longer in a nitrogen atmosphere. At that time, oxides such as magnesium, manganese, zinc, calcium, lithium, titanium, and acetate may be used as the catalyst. In the polycondensation reaction, the polycondensation reaction proceeds under a reduced pressure of 130 Pa or less until a desired molecular weight is reached at a temperature of 220 to 280 ° C. At that time, an oxide such as antimony, titanium, germanium, or acetate may be used as a catalyst.

  Since the polyester resin for the base material after polymerization contains monomers, oligomers, and by-products such as acetaldehyde and tetrahydrofuran, it was obtained by performing solid-state polymerization at a temperature of 200 ° C. or higher under reduced pressure or under an inert gas flow. A polymer having a higher degree of polymerization may be used for the polyester film substrate.

  When polymerizing the polyester resin for the substrate, an antioxidant, a heat stabilizer, an ultraviolet absorber, an antistatic agent, a slip agent, an antiblocking agent, and the like may be added as necessary. Examples of the antioxidant include hindered phenol compounds and hindered amine compounds. Examples of the heat stabilizer include phosphorus compounds. Examples of the ultraviolet absorber include benzophenone compounds and benzotriazole compounds. Examples of the antistatic material include antimony-doped tin oxide. Examples of the slip agent include surfactants. Examples of the antiblocking agent include silicon oxide.

  The polyester film of the base material used in the present invention may be an unstretched film or a stretched film. The unstretched film is supplied with a sufficiently dried polyester resin raw material to the extruder, melted at a temperature higher than the fluidity, and passed through a filter as necessary. It can be obtained by extruding onto a cooling drum whose temperature is adjusted below the point (Tg).

  In the uniaxial stretching method, the unstretched film is stretched in the temperature range of Tg to (Tg + 50 ° C.) of the polyester resin so that the stretching ratio is about 2 to 6 times in the horizontal direction or the vertical direction. In the simultaneous biaxial stretching method, the unstretched film is biaxially stretched in the temperature range of Tg to (Tg + 50 ° C.) of the polyester resin so that the stretching ratio is about 2 to 4 times in the transverse direction and the longitudinal direction. In this case, preliminary longitudinal stretching of about 1 to 1.2 times may be performed before guiding to the simultaneous biaxial stretching machine. In the sequential biaxial stretching method, the unstretched film is heated with a roll, infrared rays, or the like, and stretched in the longitudinal direction to obtain a longitudinally stretched film. Stretching is preferably performed 2.5 to 4.0 times in a temperature range of Tg to (Tg + 40 ° C.) of the polyester resin by utilizing a difference in peripheral speed of two or more rolls. Subsequently, the longitudinally stretched film is continuously subjected to transverse stretching, heat setting, and thermal relaxation to form a biaxially stretched film. The transverse stretching starts in the temperature range of Tg to (Tg + 40 ° C.) of the polyester resin, and the maximum temperature is preferably in the temperature range of (Tm-100 ° C.) to (Tm-40 ° C.) of the polyester resin (Tm Is the melting point of the polyester resin). The transverse stretching ratio is adjusted depending on the required physical properties of the final film, but is preferably 3.5 times or more, more preferably 3.8 times or more, and 4.0 times or more. Is more preferable. The film can be stretched in the machine direction and the transverse direction, and further stretched in the machine direction and / or the transverse direction to increase the elastic modulus and dimensional stability of the film. Following stretching, heat fixing treatment for several seconds in the temperature range of polyester resin (Tm-50 ° C.) to (Tm-10 ° C.) and relaxation of 1-10% in the lateral direction of the film simultaneously with the heat fixing treatment preferable.

  In order to improve the winding property of the film, particles may be added to the polyester film used for the substrate.

  The type of particles to be blended in the substrate is not particularly limited, and specific examples include, for example, silica, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, calcium phosphate, magnesium phosphate, kaolin, aluminum oxide, Inorganic particles such as titanium oxide can be used. Moreover, you may use heat-resistant organic particles, such as a thermosetting urea resin, a thermosetting phenol resin, a thermosetting epoxy resin, and a benzoguanamine resin. Furthermore, precipitated particles obtained by precipitating and finely dispersing a part of a metal compound such as a catalyst during the polyester production process can also be used. The shape of the particles to be used is not particularly limited, and any of a spherical shape, a block shape, a rod shape, a flat shape, and the like may be used. Moreover, there is no restriction | limiting in particular also about the hardness, specific gravity, a color, etc. Two or more kinds of these particles may be used in combination as required.

  The average particle size of the particles used is usually in the range of 0.01 to 3 μm, preferably 0.01 to 1 μm. When the average particle diameter is less than 0.01 μm, the particles are likely to aggregate and dispersibility may be insufficient. On the other hand, when the average particle diameter exceeds 3 μm, the surface roughness of the film becomes too rough and There may be a problem when a release layer is applied in the process.

  The particle content in the polyester film substrate is usually 5% by mass or less, preferably 0.005 to 3% by mass. If the particles are added in excess of 5% by mass, the transparency of the film may be insufficient.

  The method for adding the particles to the polyester film substrate is not particularly limited, and the particles can be added at any stage for producing the polyester resin. For example, it is an esterification stage or a transesterification completion stage.

  The substrate polyester film used in the present invention may have a single layer or multiple layers (for example, two types, two types, two types, three layers, three types, three layers). From the viewpoint of controlling the degree and improving handling properties such as winding property, a multilayer structure is preferable. Two types, two layers, and two types and three layers are particularly preferable. The two-layer / two-layer structure is a two-layer structure manufactured using two kinds of layer forming materials, and these two layers have different compositions (for example, particle content). The two-layer / three-layer configuration is a three-layer configuration manufactured using two types of layer-forming materials, and the two outermost layers and the intermediate layer have different compositions (for example, particle content). Yes. The three-layer / three-layer structure is a three-layer structure manufactured using three kinds of layer forming materials, and these three layers have different compositions (for example, particle content).

  The polyester film base material preferably has a multilayer structure in which the layer containing particles is at least an outermost layer on one side.

  When the polyester film substrate has a multilayer structure, the thickness ratio in each layer of the multilayer is from the viewpoint of stability during production and transparency, and in the case of two types and two layers, the ratio of the thickness of each layer is 99: 1 to 1. 1:99 is preferable, 96: 4 to 4:96 is more preferable, and 90:10 to 10:90 is further preferable. In the case of two types and three layers, the thickness ratio of each layer is preferably 1: 98: 1 to 49.5: 1: 49.5, more preferably 4: 92: 4 to 48: 4: 48, and 10:80. : 10-45: 10: 45 is more preferable.

A polyester film substrate having a multilayer structure can be produced, for example, by the following method;
(1) A method in which two or more kinds of polyester resin compositions (layer forming materials) are separately melted, merged and laminated in layers, extruded from a multilayer die, laminated and fused before solidification, and then solidified;
(2) A method of stretching and heat setting after the method of (1) above;
(3) A method in which two or more kinds of polyester resin compositions (layer forming materials) are separately melted, extruded without being joined together to form a film, and then two or more kinds of films are laminated and fused; and ( 4) A method of laminating and fusing two or more kinds of stretched films after forming into a film and stretching in the method of (3) above.

  For the polyester film substrate, the above-mentioned methods (1) and (2) are preferably used in which a multi-layer die is used and laminated and fused before solidification in view of the simplicity of the process.

  Examples of the method for forming the resin layer on the polyester film substrate as described above include a method in which a coating liquid containing a polyester resin is applied on the substrate and then dried.

  The application method of the coating liquid is not particularly limited, and examples thereof include a gravure roll method, a reverse roll method, an air knife method, a reverse gravure method, a Mayer bar method, an inverse roll method, or various coating methods based on a combination thereof. It is done. Various spraying methods can also be employed. The coating thickness is such that the thickness after drying (especially the thickness after heat drying) falls within the following range from the viewpoints of further reduction of the precipitated oligomer, improvement of blocking resistance, prevention of coating defects and improvement of productivity. It is preferable to make it a small value. The thickness after drying (particularly the thickness after heat drying) is preferably 0.01 to 2 μm, more preferably 0.03 to 1 μm, and even more preferably 0.04 to 0.5 μm. 0.2 to 0.5 μm is most preferable.

  Although it does not specifically limit as a drying method, From a viewpoint of the further improvement of the adhesiveness of a resin layer and a coating layer when providing a coating layer (for example, acrylic coating film) on a resin layer, it heats and performs drying. It is preferable to employ a heat drying method. The reason is not clear, but when the heat drying temperature of the resin layer is 140 ° C. or higher, particularly 180 ° C. or higher, the adhesiveness is remarkably increased. The heat drying treatment temperature is preferably 140 to 250 ° C., preferably 160 to 230 ° C., particularly 180 to 230 ° C., from the viewpoint of further improving adhesiveness and preventing heat wrinkles and deformation of the polyester film substrate. Is more preferable. The heat drying treatment time is preferably 5 to 60 seconds, and more preferably 20 to 60 seconds.

  The resin layer can be formed by an inline coating method or a post coating method. The in-line coating method is a method in which a coating liquid is applied to an unstretched film or a uniaxially stretched film and then stretched in at least one direction. The stretching method may be determined according to the stretched state of the film before coating. For example, when the film before coating is an unstretched film, the stretching method after coating is a sequential biaxial stretching method or a simultaneous biaxial stretching method. For example, when the film before coating is a film that is uniaxially stretched in a predetermined direction (MD direction or TD direction), the stretching method after coating is uniaxially stretched in the unstretched direction (TD direction or MD direction). Stretching method. On the other hand, the post-coating method is a method in which an unstretched film is converted into a biaxially stretched film by a sequential biaxial stretching method or a simultaneous biaxial stretching method, and a coating solution is applied to the biaxially stretched film.

  In general, the in-line coating method has higher productivity and is more economical than the post coating method. Further, in the in-line coating method, since the coating liquid is applied to an unstretched film or a uniaxially stretched film, it can be heated at a high temperature. In the present invention, since the resin layer is preferably heat-dried at 140 to 250 ° C., an in-line coating method that can be heated at a high temperature is preferable. By employing the in-line coating method, it is possible to suppress thermal wrinkles that occur due to the shrinkage of the polyester film accompanying the heat drying treatment.

  The polyester resin (hereinafter referred to as polyester resin (A)) used in the resin layer of the present invention is mainly composed of a dicarboxylic acid component and a diol component. That the polyester resin (A) is mainly composed of a dicarboxylic acid component and a diol component is 35 to 50 mol%, preferably 45 to 50 mol%, more preferably among all monomer components constituting the polyester resin (A). Means that 48-50 mol% is the dicarboxylic acid component and 35-50 mol%, preferably 45-50 mol%, more preferably 48-50% is the diol component. In the present specification, the content ratio of the monomer component of the polyester resin (A) is indicated by a value based on the amount of raw material used before polymerization.

  The diol component having a tricyclodecane structure must be contained in an amount of 5 mol% or more and less than 70 mol% with respect to 100 mol% of the diol component constituting the polyester resin (A). The lower limit is preferably 10 mol% or more, more preferably 15 mol% or more, and the upper limit is 60 mol% or less from the viewpoint of further improving the adhesion with the film) and further reducing the precipitated oligomer. Is preferable, and it is more preferable that it is 50 mol% or less. When the content of the diol component having a tricyclodecane structure is less than 5 mol%, the effect of suppressing the precipitation of oligomers accompanying heat treatment is low. On the other hand, in the case of 70 mol% or more, particularly when it exceeds 70 mol%, the adhesion between the resin layer to be formed and the coating layer (for example, acrylic coating film) is inferior, and the stretchability is reduced. Become.

  Examples of the diol component having a tricyclodecane structure include a tricyclodecane compound represented by the following general formula (I).

In general formula (I), X ₁ and X ₂ are a group having 1 to 4 moles of alkylene oxide added to a hydroxyalkylene group having 1 to 4 carbon atoms and / or the hydroxyalkylene group having 1 to 4 carbon atoms, They may be the same or different. The hydroxyalkylene group is a group in which one hydrogen atom of an alkyl group having 1 to 4 carbon atoms, preferably 1 to 2 carbon atoms, is substituted with one hydroxyl group. The alkyl group may be linear or branched, and is preferably linear. The alkylene oxide is not particularly limited, but is preferably an alkylene oxide compound having 2 to 4 carbon atoms. Examples of the alkylene oxide include ethylene oxide, propylene oxide, and butylene oxide. Addition of an alkylene oxide to a hydroxyalkylene group produces an ether bond based on the hydroxyl group of the hydroxyalkylene group and a hydroxyl group based on the epoxy group of the alkylene oxide. X ₁ and X ₂ usually only have to be bonded to different carbon atoms out of 10 carbon atoms constituting the three carbon 5-membered rings of the tricyclodecane structure, preferably different carbon 5-membered rings. It is bonded to the constituent carbon atoms, and more preferably X ₁ and X ₂ are bonded to the 6- and 2-positions of the tricyclodecane structure, respectively. A carbon atom constituting the tricyclodecane structure may be substituted with a monovalent substituent. Although it does not specifically limit as a monovalent substituent, For example, a C1-C3 alkyl group (specifically a methyl group, an ethyl group, a propyl group) is mentioned. Most preferred X ₁ and X ₂ are hydroxyalkylene groups having 1 to 4 carbon atoms, particularly 1 to 2 carbon atoms, which may be the same or different. The diol component having a tricyclodecane structure may be two or more compounds having different structures.

Examples of the compound represented by the general formula (I) include tricyclo [5.2.1.0 ^2,6 ] decandimethanol, 4,10-dimethyltricyclo [5.2.1.0 ^2,6 ]. Decandimethanol, 4,4,10,10-tetramethyltricyclo [5.2.1.0 ^2,6 ] decandimethanol, 1,2,3,4,5,6,7,8,9, An example is 10-decamethyltricyclo [5.2.1.0 ^2,6 ] decandimethanol. Of these, tricyclo [5.2.1.0 ^2,6 ] decanedimethanol is preferred because of its high versatility and high adhesion between the coating and the acrylic coating. In addition, you may use these in mixture of 2 or more types.

  Examples of the diol component that can be used in combination with the compound represented by the general formula (I) include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, and 2-methyl-1 , 3-propanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,9-nonanediol, 2-ethyl-2-butylpropane Aliphatic glycols such as diols, 1,4-cyclohexanedimethanol, 1,3-cyclobutanedimethanol, dimethanol decalin, dimethanol bicyclooctane and other alicyclic glycols, diethylene glycol, triethylene glycol, dipropylene glycol, polytetra Methylene glycol, polyethylene glycol And glycols containing ether bonds such as polypropylene glycol, alkylene oxide adducts of 2,2-bis [4- (hydroxyethoxy) phenyl] propane, and alkylene oxide adducts of bis [4- (hydroxyethoxy) phenyl] sulfone. . Among them, one or more diol components selected from the group consisting of aliphatic glycols, particularly ethylene glycol, neopentyl glycol, and 1,2-propanediol, in terms of influence on versatility, polymerizability, and resin properties, It is preferably used together with a diol component having a tricyclodecane structure.

  The content of the aliphatic glycol is usually 95 mol% or less, particularly 30 mol% or more and 95 mol% or less with respect to 100 mol% of the diol component constituting the polyester resin (A). For example, from the viewpoint of further improving adhesiveness with an acrylic coating) and further reducing the amount of precipitated oligomers, it is preferably 31 to 85 mol%, more preferably 50 to 85 mol%. The content is preferably 51 to 85 mol% from the viewpoints of further improvement of adhesiveness, further reduction of precipitated oligomers and improvement of blocking resistance.

  The polyester resin (A) can be easily dispersed in water or a hydrophilic organic solvent by having a dicarboxylic acid having a sulfonate group. When the content of the dicarboxylic acid having a sulfonate group is 3 mol% or more with respect to 100 mol% of the dicarboxylic acid component constituting the polyester resin (A), the stretchability of the resin layer to in-line coating is enhanced. On the other hand, the water resistance of the resin layer is improved by setting it to 15 mol% or less, preferably 9 mol% or less, and particularly 8 mol% or less. Therefore, it is preferable from a water-resistant viewpoint that 0.1-15 mol% of dicarboxylic acid which has a sulfonate group is contained with respect to 100 mol% of dicarboxylic acid component which comprises a polyester resin (A), and water resistance is further improved. From the viewpoint of improving the stretch followability (at the time of in-line coating), it is more preferably 3 to 9 mol%, particularly 3 to 8 mol%. Stretching followability is a property that even when stretching is performed after the resin layer is formed, the resin layer can be satisfactorily stretched following the polyester film substrate. The water resistance is a property that can prevent appearance changes such as whitening and swelling occurring in the resin layer even when the laminated film of the present invention is immersed in water.

  As the dicarboxylic acid having a sulfonate group, sodium sulfophthalate is preferable. For example, 5-sodium sulfoisophthalic acid, 5-sodium sulfoterephthalic acid, 5-potassium sulfoisophthalic acid, 5-potassium sulfoterephthalic acid, 5-lithium Sulfoisophthalic acid, 5-lithium sulfoterephthalic acid, sodium 3,5-di (carbo-β-hydroxyethoxy) benzenesulfonate, sodium 2,5-di (carbo-β-hydroxyethoxy) benzenesulfonate, 3,5 -Potassium di (carbo-β-hydroxyethoxy) benzenesulfonate, lithium 3,5-di (carbo-β-hydroxyethoxy) benzenesulfonate, dimethyl 5-sodium sulfoisophthalate, dimethyl 5-sodium sulfoterephthalate, 5 − Potassium sulfoisophthalic acid dimethyl, include 5 lithium sulfoisophthalic acid dimethyl.

  The dicarboxylic acid component other than the dicarboxylic acid having a sulfonate group is not particularly limited, and examples thereof include terephthalic acid, isophthalic acid, phthalic acid, phthalic anhydride, 2,6-naphthalenedicarboxylic acid, and 3-tert-butylisophthalic acid. Aromatic dicarboxylic acids such as diphenic acid, oxalic acid, succinic acid, succinic anhydride, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, aicosane diacid, hydrogenated dimer acid, etc. Acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, citraconic acid, citraconic anhydride, dimer acid and other unsaturated aliphatic dicarboxylic acids, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 2,5-norbornene dicarboxylic acid And their anhydrides, alicyclic dicarboxylic acids such as tetrahydrophthalic acid and its anhydride. Of these, aromatic dicarboxylic acids, particularly terephthalic acid, isophthalic acid, and 2,6-naphthalenedicarboxylic acid are preferred from the viewpoint of versatility, polymerizability, and resin properties.

  The content of the aromatic dicarboxylic acid is usually 70 to 97 mol% with respect to 100 mol% of the dicarboxylic acid component constituting the polyester resin (A), and adhesion between the resin layer and the coating layer (for example, acrylic coating film). From the viewpoint of further improving the property and further reducing the amount of precipitated oligomer, it is preferably 80 to 95 mol%.

  The polyester resin (A) may contain a hydroxycarboxylic acid component. Examples of the hydroxycarboxylic acid include 2-hydroxy sebacic acid, 5-hydroxyisophthalic acid, 4-hydroxyisophthalic acid, citric acid, isocitric acid, malic acid, 2-methyl-2-hydroxysuccinic acid, tartaric acid, tetrahydroxyadipine Examples thereof include alkylene oxide adducts of acid, ε-caprolactone, δ-valerolactone, γ-valerolactone, lactic acid, β-hydroxybutyric acid, p-hydroxybenzoic acid, and 4-hydroxyphenyl stearic acid. When using hydroxycarboxylic acid, the content is preferably 50 mol% or less, more preferably 40 mol% or less, out of a total of 100 mol% of all monomer components constituting the polyester resin (A). Preferably, it is more preferably 30 mol% or less.

  The polyester resin (A) may contain a monocarboxylic acid component or a monoalcohol component. Examples of the monocarboxylic acid include benzoic acid, phenylacetic acid, lauric acid, palmitic acid, stearic acid, oleic acid and the like. Examples of the monoalcohol include cetyl alcohol, decyl alcohol, lauryl alcohol, myristyl alcohol, octyl alcohol, and stearyl alcohol.

  The polyester resin (A) may contain a trifunctional or higher functional carboxylic acid or a trifunctional or higher functional alcohol. When the trifunctional or higher functional carboxylic acid or the trifunctional or higher functional alcohol is charged before the esterification reaction, the content may be 5 mol% or less with respect to 100 mol% of the dicarboxylic acid component or dialcohol component, respectively. Preferably, it is 4 mol% or less, more preferably 3 mol% or less.

  Examples of the tri- or higher functional carboxylic acid include trimellitic acid, benzophenone tetracarboxylic acid, trimellitic anhydride, pyromellitic acid, pyromellitic anhydride, benzophenone tetracarboxylic anhydride, trimesic acid, ethylene glycol bis (anhydrotrimethyl). And glycerol tris (anhydro trimellitate), 1,2,3,4-butanetetracarboxylic acid. Examples of the trifunctional or higher functional alcohol include glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol.

  The glass transition temperature of the polyester resin (A) is not particularly limited, but is 60 to 110 ° C., particularly more than 70 ° C. and 110 ° C. or less, from the viewpoint of improving the blocking resistance and stretchability of the resulting resin layer. It is preferable, and 80-110 degreeC is preferable from a viewpoint of the further improvement of blocking resistance. A glass transition temperature becomes so high that there are many diol components which have a tricyclodecane structure among the diol components which comprise a polyester resin (A). In diol components other than the diol component having a tricyclodecane structure, the glass transition temperature increases as the amount of the above-described aliphatic glycol component increases. The blocking resistance is a property that even if the laminated films of the present invention are stacked and stored at a high temperature, adhesion (blocking) does not occur between the films, and even if they occur, they can be easily peeled off.

  A polyester resin (A) can be manufactured by a well-known method combining the said monomer. For example, all the monomer components and / or low polymers thereof are reacted in an inert atmosphere to carry out an esterification reaction, followed by polycondensation reaction in the presence of a polycondensation catalyst under reduced pressure until the desired molecular weight is reached. A method of proceeding and a method of performing a depolymerization reaction by adding a tri- or higher functional carboxylic acid under an inert atmosphere after carrying out the method.

  In the esterification reaction, the reaction temperature is preferably 180 to 260 ° C., and the reaction time is preferably 2.5 to 10 hours, more preferably 4 to 6 hours.

  In the polycondensation reaction, the reaction temperature is preferably 220 to 280 ° C. The degree of vacuum is preferably 130 Pa or less. If the degree of vacuum is low, the polycondensation time may be long. It is preferable to gradually reduce the pressure over 60 to 180 minutes until the atmospheric pressure reaches 130 Pa or less.

  Although it does not specifically limit as a polycondensation catalyst, Well-known compounds, such as a zinc acetate, an antimony trioxide, a tetra- n-butyl titanate, n-butylhydroxy oxo tin, can be mentioned. It is preferable that the usage-amount of a catalyst shall be 0.1-20 * 10 <-4> mol with respect to 1 mol of dicarboxylic acid components.

  In the depolymerization, the reaction temperature is preferably 160 to 280 ° C., and the reaction time is preferably 0.5 to 5 hours.

The resin layer constituting the laminated film of the present invention is a curing agent added to the polyester resin from the viewpoint of good adhesion of the resin layer, maintenance of adhesion when stored for a long time in a high temperature environment, and good water resistance. The resin layer can be formed, for example, by applying and drying a coating liquid containing a polyester resin and a curing agent.
The coating liquid used for forming the resin layer can be mixed with a polyester resin and a curing agent at an arbitrary stage. For example, after mixing a polyester resin and a curing agent, a method of dissolving or dispersing into a coating liquid, and a method of mixing a polyester resin and a curing agent as a solution or a dispersion, respectively, to form a coating liquid, In the present invention, the latter method is preferred.

  Examples of the coating liquid include an organic solution obtained by dissolving a polyester resin (A) and a curing agent in an organic solvent, and a dispersion obtained by dispersing the polyester resin (A) and a curing agent in an organic solvent and / or water. In the present invention, it is preferable to use an aqueous dispersion dispersed in water from the viewpoint of working environment and the like.

The coating solution as the organic solution is produced by a method in which the polyester resin (A) and the curing agent are dissolved in an organic solvent.
The organic solvent for dissolving the polyester resin is not particularly limited as long as the polyester resin and the curing agent can be dissolved. Among the organic solvents, those having a boiling point of 180 ° C. or lower are preferable, and those having a boiling point of 165 ° C. or lower are more preferable. Preferably, the thing below 150 degreeC is more preferable. If the boiling point of the organic solvent exceeds 180 ° C., it may be difficult to volatilize the organic solvent by drying during coating.

  The coating liquid as a dispersion is produced by a method in which the polyester resin (A) and the curing agent are dispersed in an organic solvent and / or water. From the viewpoint of workability, a method in which a polyester resin (A) dispersion and a curing agent solution or dispersion are prepared and mixed to form a coating solution is preferable.

  Examples of the method for producing the dispersion of the polyester resin (A) include a self-emulsification method. The self-emulsification method is a method for preparing a polyester resin aqueous dispersion containing an organic solvent by charging the polyester resin (A), water, and an organic solvent all at once and heating the system while stirring. If necessary, a basic compound may be added.

  Examples of the organic solvent used for producing the dispersion include acetone (boiling point: 56.2 ° C.), methyl ethyl ketone (boiling point: 79.6 ° C.), methyl isobutyl ketone (boiling point: 117 ° C.), cyclohexanone (boiling point: Ketone organic solvents such as toluene (boiling point: 111 ° C.) and xylene (boiling point: 140 ° C.); ethylene glycol monoethyl ether (boiling point: 136 ° C.), tetrahydrofuran ( Boiling point: 66.0 ° C), 1,4-dioxane (boiling point: 101 ° C) and other ether-based organic solvents; halogen-containing organic solvents; n-propanol (boiling point: 97.2 ° C), isopropanol (boiling point: 82. Alcohol-based organic solvents such as 4 ° C; Estes such as ethyl acetate (boiling point: 77.1 ° C) and normal butyl acetate (boiling point: 126 ° C) System organic solvent; and glycol-based organic solvents. These may be used alone or in combination.

  In the production of the dispersion, a step of removing the organic solvent (solvent removal step) may be further provided after the dispersion step. The organic solvent content after the desolvation step is preferably less than 1% by mass of the dispersion, more preferably less than 0.5% by mass, and even more preferably less than 0.3% by mass. .

  In the present invention, the coating liquid preferably contains no emulsifier. The emulsifier as used in the present invention includes a surfactant, a compound having a protective colloid effect, a modified wax, an acid-modified product having a high acid value, a water-soluble polymer, and the like. Such an emulsifier may be contained in an amount less than 0.1 parts by mass with respect to 100 parts by mass of the polyester resin (A) component as long as the effects of the present invention are not impaired. When 0.1 mass part or more of an emulsifier is contained, it exists in the tendency for the water resistance of a film to fall.

  The resin layer in the present invention needs to contain a curing agent. The content of the curing agent is the stability of the coating liquid, coat cracking when stretched, further reduction of precipitated oligomers, in a high temperature environment. From the viewpoint of maintaining adhesion when used for a long period of time, the curing agent needs to be 0.1 to 30 parts by mass with respect to 100 parts by mass of the polyester resin (A), and 1 to 10 parts by mass. Preferably, it is 1-8 mass parts, More preferably, it is 1-5 mass parts.

  Examples of the curing agent that can be used in the present invention include a polyfunctional epoxy compound; a polyfunctional isocyanate compound; a polyfunctional aziridine compound; a carbodiimide group-containing compound; an oxazoline group-containing compound; a phenol resin; and a urea resin, a melamine resin, and a benzoguanamine. Examples include amino resins such as resins, and one of these may be used, or two or more may be used in combination. Preferred curing agents are one or more curing agents selected from the group consisting of polyfunctional isocyanate compounds, carbodiimide group-containing compounds, oxazoline group-containing compounds, and melamine resins, and the most preferred curing agents are oxazoline group-containing compounds. .

  Specific examples of the polyfunctional epoxy compound include polyepoxy compounds and diepoxy compounds. Examples of the polyepoxy compound include sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, triglycidyl tris (2-hydroxyethyl) isocyanate, glycerol polyglycidyl ether, trimethylolpropane. Polyglycidyl ether can be used. Examples of the diepoxy compound include neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, resorcin diglycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, and polypropylene glycol diester. Glycidyl ether and polytetramethylene glycol diglycidyl ether can be used.

  Examples of the polyfunctional isocyanate compound include tolylene diisocyanate, diphenylmethane-4,4′-diisocyanate, metaxylylene diisocyanate, hexamethylene-1,6-diisocyanate, 1,6-diisocyanate hexane, tolylene diisocyanate and hexanetriol. Adduct, adduct of tolylene diisocyanate and trimethylolpropane, polyol-modified diphenylmethane-4,4'-diisocyanate, carbodiimide-modified diphenylmethane-4,4'-diisocyanate, isophorone diisocyanate, 1,5-naphthalene diisocyanate, 3,3 ' -Vitrylene-4,4 'diisocyanate, 3,3' dimethyldiphenylmethane-4,4'-diisocyanate, metaphenylene diisocyanate, etc. Possible it is. Block isocyanate compounds in which these isocyanate groups are blocked with bisulfites and phenols containing sulfonic acid groups, alcohols, lactams, oximes and active methylene compounds may be used.

  As the polyfunctional aziridine compound, for example, N, N′-hexamethylene-1,6-bis- (1-aziridinecarboxamide), trimethylolpropane-tri-β-aziridinylpropionate, etc. can be used. is there.

  The carbodiimide group-containing compound is not particularly limited as long as it has at least two carbodiimide groups in the molecule. For example, compounds having a carbodiimide group such as p-phenylene-bis (2,6-xylylcarbodiimide), tetramethylene-bis (t-butylcarbodiimide), cyclohexane-1,4-bis (methylene-t-butylcarbodiimide) Alternatively, polycarbodiimide, which is a polymer having a carbodiimide group, can be used. These 1 type (s) or 2 or more types can be used.

  As the oxazoline group-containing compound, a polymer containing an oxazoline group can be used. Such a polymer can be prepared by polymerization of an addition polymerizable oxazoline group-containing monomer alone or with another monomer. Addition polymerizable oxazoline group-containing monomers include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, Examples include 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-ethyl-2-oxazoline, and the like. As the addition polymerizable oxazoline group-containing monomer, one or a mixture of two or more of these can be used. Among these, 2-isopropenyl-2-oxazoline is preferred because it is easily available industrially. The other monomer is not limited as long as it is a monomer copolymerizable with an addition-polymerizable oxazoline group-containing monomer, such as alkyl acrylate, alkyl methacrylate (the alkyl group includes a methyl group, an ethyl group, an n-propyl group, an isopropyl group, (meth) acrylic acid esters such as n-butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group); acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, styrene Unsaturated carboxylic acids such as sulfonic acid and its salts (sodium salt, potassium salt, ammonium salt, tertiary amine salt, etc.); Unsaturated nitriles such as acrylonitrile, methacrylonitrile; acrylamide, methacrylamide, N-alkylacrylamide N-alkyl methacrylate N, N-dialkylacrylamide, N, N-dialkylmethacrylate (alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, 2-ethylhexyl Group, cyclohexyl group, etc.); vinyl esters such as vinyl acetate and vinyl propionate; vinyl ethers such as methyl vinyl ether and ethyl vinyl ether; α-olefins such as ethylene and propylene; vinyl chloride and vinylidene chloride And halogen-containing α, β-unsaturated aliphatic monomers such as vinyl fluoride; α, β-unsaturated aromatic monomers such as styrene and α-methylstyrene. As the other monomer, one or more of these monomers can be used.

  Examples of phenol resins include resol type phenol resins and / or novolac types prepared from phenol, bisphenol A, pt-butylphenol, octylphenol, alkylphenols such as p-cumylphenol, p-phenylphenol, cresol and the like as raw materials. Phenolic resins can be used.

  As the urea resin, for example, dimethylol urea, dimethylol ethylene urea, dimethylol propylene urea, tetramethylol acetylene urea, 4-methoxy 5-dimethylpropylene urea dimethylol can be used.

  The melamine resin is a compound having, for example, an imino group, a methylol group, and / or an alkoxymethyl group (for example, a methoxymethyl group or a butoxymethyl group) as a functional group in one molecule. As the melamine resin, an imino group-type methylated melamine resin, a methylol group-type melamine resin, a methylol group-type methylated melamine resin, a complete alkyl-type methylated melamine resin, or the like can be used. Of these, methylolated melamine resins are most preferred. Furthermore, it is preferable to use an acidic catalyst such as p-toluenesulfonic acid in order to accelerate the thermosetting of the melamine resin.

  As the benzoguanamine resin, for example, trimethylol benzoguanamine, hexamethylol benzoguanamine, trismethoxymethylbenzoguanamine, hexakismethoxymethylbenzoguanamine and the like can be used.

  Particles may be contained in the resin layer in order to impart easy slipping and blocking resistance.

  The type of particles that can be blended is not particularly limited as long as it does not affect the adhesion and oligomer precipitation suppression effect. Specific examples include silica, talc, mica, kaolin, swellable fluoromica, montmorillonite, hectorite, Examples thereof include calcium carbonate, magnesium carbonate, calcium oxide, zinc oxide, magnesium oxide, sodium silicate, aluminum hydroxide, iron oxide, zirconium oxide, barium sulfate, titanium oxide, and carbon black. Of these, silica, talc, mica, and kaolin are preferred because they are highly effective in exhibiting heat resistance and transparency of the resulting coating, and silica is most preferred because of excellent slipperiness. Examples of the organic particles include acrylic particles, silicone particles, polyimide particles, Teflon (registered trademark) particles, crosslinked polyester particles, crosslinked polystyrene particles, crosslinked polymer particles, and core-shell particles. These particles can be used alone or in combination.

  The particles can be blended at any stage of preparing the coating solution. For example, there may be mentioned a method of adding a particle dispersion to the coating solution and mixing and stirring.

  When blending the particles, from the viewpoint of blocking resistance and adhesiveness of the coating film, the total mass of the polyester resin (A) and the curing agent, the polyester resin (A) + the curing agent, {polyester resin (A ) + Curing agent} / particle = 99/1 to 70/30 (mass ratio) is preferable, 99/1 to 80/20 (mass ratio) is more preferable, and 99/1 to 90/10. (Mass ratio) is more preferable.

  The coating liquid can further contain other optional components. Examples of optional components that can be blended include leveling agents, antifoaming agents, other thickeners, color pigments, water, alcohol, and the like.

  Examples of the leveling agent include silicone-based and fluorine-based leveling agents. Particularly, the silicone-based leveling agent is preferable from the viewpoint of compatibility with the coating liquid, coating suitability, adhesion, and blocking resistance. Examples of the silicone leveling agent include reactive silicone, polydimethylsiloxane, polyether-modified polydimethylsiloxane, and polymethylalkylsiloxane. By using a leveling agent, it is possible to improve the wettability during coating and to improve the smoothness of the coating. As a compounding quantity of a leveling agent, it is preferable that it is 1-15 mass% in a coating liquid.

  As the antifoaming agent, for example, an acetylene glycol compound or an ethylene oxide adduct thereof is preferable. Specifically, 3,6-dimethyl-4-decyne-3,6-diol, 2,4,7,9-tetramethyl-5-decyne-4,7-diol and compounds obtained by adding ethylene oxide thereto Is effective. By using an antifoaming agent, generation of bubbles mixed in the dispersion during coating can be suppressed, and the smoothness and transparency of the resulting coating can be improved. As a compounding quantity of an antifoamer, it is preferable that it is 1-10 mass% in a coating liquid.

  Although the thickness of the polyester-type laminated | multilayer film of this invention is not specifically limited, It is preferable that it is 15-150 micrometers. By setting the thickness to 15 to 150 μm, a film can be produced with high productivity.

  In the polyester-based laminated film of the present invention, the polyester film substrate is preferably stretched in at least one direction. By being stretched, the flatness and heat resistance of the film can be improved.

  In the polyester-based laminated film of the present invention, oligomer precipitation from the base film during heat treatment is suppressed. Specifically, the haze change amount when heat-treated at 150 ° C. for 1 hour is 1.0% or less. Preferably, it is 0.5% or less. Further, as a more severe condition, even when heat treatment is performed at 180 ° C. for 30 minutes, the amount of change in haze is 1.5% or less, preferably 1.0% or less.

  In this specification, the amount of change in haze is based on a value measured according to JIS-K7136: 2000.

  The polyester-based laminated film of the present invention has good adhesion to various coating layers, particularly acrylic hard coat resins, reduces oligomers that precipitate during heat treatment, and adheres even after long-term storage in a high-temperature environment. Sex is maintained. For this reason, it can be suitably used as an easily adhesive film for optics such as a touch panel display.

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.
<Evaluation of characteristics>

〔water resistant〕
The laminated film was immersed in distilled water at 25 ° C., gently pulled up after 24 hours and air-dried, and then the appearance of the resin layer was visually observed.
○: No change in appearance.
Δ: Part of the resin layer was whitened or swollen (no problem in practical use).
X: The entire resin layer was dissolved or swollen.

〔Adhesiveness〕
Acrylic hard coat resin (Seika Beam PHC, manufactured by Dainichi Seika Co., Ltd.) is applied onto the resin layer of the laminated film using a desktop coating device, and a low-pressure mercury lamp UV curing device (Toshiba Lighting & Technology Corp., 40 mW / cm, one lamp) Curing was performed according to the formula (1) to form a hard coat layer having a thickness of 3 μm. Adhesiveness was confirmed by a cross-cut method in which an adhesive tape was applied to the coating obtained by cutting and forming a lattice pattern of 100 sections in accordance with JIS K-5600-5-6. In addition, “100/100” is the best state with no separation at 100 sections, and “0/100” indicates the state where all 100 sections are peeled off and is not the best. 100/100 to 90/100 is accepted, 100/100 to 95/100, particularly 100/100 to 98/100, is excellent, and 100/100 is the most excellent.

[Adhesion after long-term storage in high temperature environment]
Acrylic hard coat resin (Seika Beam PHC, manufactured by Dainichi Seika Co., Ltd.) is applied onto the resin layer of the laminated film using a desktop coating device, and a low-pressure mercury lamp UV curing device (Toshiba Lighting & Technology Corp., 40 mW / cm, one lamp) Curing was performed according to the formula (1) to form a hard coat layer having a thickness of 3 μm. The film with the hard coat layer laminated is stored for 30 days under conditions of 70 ° C. and 80% RH, and then the coating is cut according to JIS K-5600-5-6 to form a lattice pattern of 100 sections. Adhesion was confirmed by a cross-cut method in which an adhesive tape was applied to the coated film and pulled apart. In addition, “100/100” is the best state with no separation at 100 sections, and “0/100” indicates the state where all 100 sections are peeled off and is not the best. 100/100 to 90/100 is accepted, 100/100 to 95/100, particularly 100/100 to 98/100, is excellent, and 100/100 is the most excellent.

[Glass transition temperature of polyester resin]
10 mg of the polyester resin is weighed, and using an input compensation type differential scanning calorimeter (DSC manufactured by PerkinElmer; Diamond DSC type, detection range: −50 ° C. to 200 ° C.) under the temperature rising rate of 10 ° C./min. Measurements were made. In the obtained temperature rise curve, the temperature at the intersection of the straight line obtained by extending the low temperature side baseline to the high temperature side and the tangent drawn at the point where the slope of the step change part of the glass transition becomes maximum is obtained. The glass transition temperature was determined.

[Change in haze]
A transparent adhesive sheet (LUCIACS CS9621T made by Nitto Denko) was pasted on the non-coated surface of the laminated film, and the haze value before the heat treatment of the laminated film using a haze meter NDH4000 (Nippon Denshoku) based on JIS-K7136: 2000 Was measured. Next, the laminated film was put into an oven heated to 150 ° C. and taken out after heat treatment for 1 hour. Thereafter, the haze value of the obtained film was measured again by the same method as described above. About the obtained film, the difference of the haze value after heat processing and before heat processing was made into the variation | change_quantity of haze.
The measurement of the amount of haze change was also performed when the heat treatment condition was changed to 180 ° C. and 30 minutes.

[Stability of coating solution]
The prepared coating solution was allowed to stand at 25 ° C. for 5 days, and gelation and sedimentation of the coating solution components were visually observed.
○: Gelation, sedimentation, etc. were not confirmed, and it was stable.
(Triangle | delta): Although coating was possible, it was gelatinized a little, or sedimentation of the component was confirmed, but it returned to the original state by stirring again.
X: Completely gelled and cannot be applied, components were settled, and the coating solution was separated.

[Blocking resistance]
The laminated film is cut into a size of 50 mm × 50 mm, and the laminated film and a biaxially stretched polyethylene terephthalate (PET) film (S-50, manufactured by Unitika) are biaxially stretched with the coated surface (resin layer) of the laminated film. The layers were superposed so that they contacted the non-corona surface of the PET film, and left for 24 hours at 60 ° C. under a load of 10 kPa. After removing the load and cooling to room temperature, blocking resistance was evaluated by examining the adhesion between the resin layer and the PET film.
○: Adhesion is not recognized between the laminated films in contact.
(Triangle | delta): Although close_contact | adherence was recognized between the laminated | multilayer films which contact, it peels easily and a change, such as whitening, is not seen by the resin layer (no problem practically).
X: Between the laminated | multilayer films which contact, a resin layer raise | generates cohesive failure, or the resin layer after peeling has become white as a whole.

[Preparation of polyester resin]
Preparation Example 1
A mixture of 3057 g of terephthalic acid, 474 g of dimethyl 5-sodium sulfoisophthalate, 1154 g of ethylene glycol and 275 g of tricyclo [5.2.1.0 ^2,6 ] decanedimethanol was heated in an autoclave at 250 ° C. for 4 hours. An esterification reaction was performed. At this time, the monomer component was blended with terephthalic acid: 5-sodium sulfoisophthalate dimethyl: ethylene glycol: tricyclo [5.2.1.0 ^2,6 ] decanedimethanol = 92: 8: 93: 7 (molar ratio). ). Next, 0.525 g of antimony trioxide, 0.328 g of triethyl phosphate and 1.580 g of zinc acetate dihydrate were added as catalysts, the temperature of the system was raised to 250 ° C., and the pressure of the system was 0.4 MPa. Suppressed and reacted for 3 hours. Thereafter, the pressure was gradually released, and the reaction was performed at normal pressure for 1 hour. Thereafter, the temperature was raised to 270 ° C. and gradually decreased to 13 Pa after 1 hour. The polycondensation reaction was continued under these conditions, and the polycondensation reaction was terminated after 2 hours and 30 minutes by setting the system to normal pressure with nitrogen gas. Thereafter, the system was pressurized with nitrogen gas, and the resin was dispensed into a sheet and allowed to cool. Next, the mixture was pulverized with a crusher, and a fraction having an opening of 1 to 6 mm was collected using a sieve to obtain a granular polyester resin (P-1) having the composition shown in Table 1.

Preparation Examples 2-8
The polyester resins (P-2) to (P-) are the same as the polyester resin (P-1) except that the resin composition is changed so that the resin composition after polymerization is as described in Tables 1 and 2. 8) were obtained respectively. The results are shown in Tables 1 and 2.

In Tables 1 and 2, abbreviations indicate the following.
TPA: terephthalic acid SIP: 5-sodium sulfoisophthalic acid EG: ethylene glycol TCD: tricyclo [5.2.1.0 ^2,6 ] decanedimethanol PD: 1,2-propanediol

Coating liquid production example 1
Using a jacketed cylindrical glass container (with an internal volume of 3 L) and a stirrer (manufactured by Tokyo Science Instruments Co., Ltd., “MAZELA NZ-1200”), 300 g of polyester resin (P-1) and 50 g of isopropanol Then, 650 g of distilled water was charged in each glass container, and the temperature was raised by passing hot water into the jacket while stirring while maintaining the rotation speed of the stirring blade at 70 rpm. When the internal temperature reached 80 ° C., the temperature was raised and stirring was continued for 90 minutes. During stirring, the internal temperature was kept at 72 ± 2 ° C. Thereafter, cold water was passed through the jacket, and the rotation speed was lowered to 30 rpm and the mixture was stirred and cooled to 25 ° C. to obtain a polyester resin dispersion. 800 g of the obtained polyester resin dispersion was charged into a round bottom flask, 40 g of water was added, a mechanical stirrer and a Liebig condenser were installed, the flask was heated in an oil bath, and 40 g of an aqueous medium was distilled off at normal pressure. Thereafter, the mixture was cooled to room temperature, and further with stirring, ion-exchanged water was finally added so that the solid content concentration was 30% by mass to obtain a polyester resin dispersion.
This polyester resin dispersion and an aqueous curing agent dispersion (oxazoline group-containing compound, Epocros WS-700; manufactured by Nippon Shokubai Co., Ltd.) are blended so that the solids mass ratio becomes 100/5, and mixed and stirred for coating. A liquid (S-1) was obtained.

Production Examples 2-19 of Coating Liquid
Except having changed the kind of polyester resin, and the kind and addition amount of a hardening | curing agent as described in Table 1-2, operation similar to manufacture example 1 was performed, and coating liquid (S-2)- (S-19) was obtained.

The following compounds were used as the curing agent.
Carbodilite V-02-L2 (Nisshinbo Co., Ltd.) was used as the carbodiimide group-containing compound.
Vasonate HW-100 (manufactured by BASF) was used as the polyfunctional isocyanate compound.
Changchun melamine resin M-30WT (manufactured by Chang Chun Plastic Co., Ltd.) was used as the melamine resin.

[Example A, Comparative Example A (Production of Post Coat Film)]
Example A1
On the corona-treated surface of a biaxially stretched polyethylene terephthalate (PET) film (S-50, manufactured by Unitika, thickness 50 μm, Hz 3.8%), a tabletop coating device (film applicator manufactured by Yasuda Seiki Co., Ltd .; No. 542) The coating liquid (S-1) was post-coated using an AB type and a bar coater) so that the resin layer thickness after the heat drying treatment was 0.24 μm. Then, the postcoat film was obtained by making it dry for 30 seconds in the hot air dryer set to 180 degreeC.

Examples A2-A13 and Comparative Examples A1-A6
Except having changed the coating liquid to be used as described in Table 1-2, the same operation as Example A1 was performed and the postcoat film was obtained.

[Example B, Comparative Example B (production of in-line coated film)]
Extruded molten polyethylene terephthalate resin (polymerization catalyst is antimony trioxide, intrinsic viscosity 0.67, glass transition temperature 78 ° C, melting point 253 ° C, 0.07 wt% silica contained) from T-die, and surface temperature is adjusted to 20 ° C The film was brought into close contact with the cooled drum and quenched to obtain an unstretched film having a thickness of 1000 μm. Subsequently, after preheating with a preheating roll group whose temperature is adjusted to 90 ° C., the longitudinal speed is changed 4.0 times by changing the peripheral speed between the drawing rolls whose temperature is adjusted to 90 ° C., thereby obtaining a 250 μm thick longitudinally stretched film. It was. Next, the longitudinally stretched film was coated in-line with the coating liquid (S-1) using a Meyer bar so that the resin layer thickness after the thermal drying treatment was 0.19 μm, and then led to a tenter type stretching machine, where a preheating temperature of 90 The film was stretched 5 times at a stretching temperature of 120 ° C., followed by a heat drying treatment at 230 ° C., followed by a relaxation treatment of 3% in the transverse direction at 200 ° C. The film coming out of the tenter was wound up at a film speed of 150 m / min. Thus, a biaxially stretched polyester film having a thickness of 50 μm was obtained. The Hz value of the film having no resin layer was 3.8.

Examples B2-13, Comparative Examples B1-B6
An in-line coated film was obtained by performing the same operation as in Example B1 except that the coating liquid used was changed as shown in Tables 1 and 2.

  The laminated films obtained in Examples and Comparative Examples and the evaluation results are shown in Tables 1 and 2.

  In Examples A1 to A13, B1 to 8 and 11 to 13, according to a predetermined composition, the obtained coating liquid had good stability, and the resin layer obtained from the coating liquid had adhesiveness and a high temperature environment. Even when stored for a long period of time, the adhesiveness was excellent, and the change in the haze value (ΔH) associated with the heat treatment was suppressed.

  In particular, Examples A2, A3, A6 and A11-A13 In Examples B2, B3, B6 and B11-B13, the amounts of TCD and curing agent contained in the coating were all in the optimum range. The liquid showed high stability. Moreover, the obtained coating film showed more excellent adhesiveness. Furthermore, since precipitation of the oligomer accompanying the heat treatment was further suppressed, the change in haze value (ΔH) was further suppressed.

  In particular, in Examples B1 to B8 and B11 to B13, the adhesiveness of the resin layer was further improved as compared with Examples A1 to A8 and A11 to A13 by performing a heat drying treatment in an in-line process.

  In Comparative Example A1, since the TCD component in the diol component of the polyester resin (A) was too much, the adhesiveness was lowered.

  In Comparative Examples A2 and B2 and Comparative Examples A3 and B3, since the TCD component in the diol component of the polyester resin (A) was too small, the haze value change (ΔH) accompanying the heat treatment was remarkably large.

  In Comparative Examples A4 and B4 and Comparative Examples A5 and B5, since the curing agent was not contained with respect to 100 parts by mass of the polyester resin (A) or the content was less than the specified amount of the present invention, the water resistance of the resin layer And adhesiveness after long-term storage in a high temperature environment deteriorated significantly.

  In Comparative Examples A6 and B6, since the content of the curing agent was too much than the specified amount of the present invention, the coating liquid was gelled and could not be applied.

  The laminated film of the present invention is useful as an electronic material, an optical material, or an electro-optical material.

Claims (4)

  A polyester film having a resin layer on at least one surface of a polyester film substrate, wherein the resin layer contains 0.1 to 30 parts by mass of a curing agent with respect to 100 parts by mass of a polyester resin, and constitutes the resin layer A polyester-based laminated film, wherein 5 mol% or more and less than 70 mol% of a diol component of a resin is a diol component having a tricyclodecane structure.   2. The curing agent according to claim 1, wherein the curing agent is at least one curing agent selected from the group consisting of a polyfunctional isocyanate compound, a carbodiimide group-containing compound, an oxazoline group-containing compound, and a melamine resin. Polyester-based laminated film. 3. The polyester-based laminate according to claim 1, wherein a heat-drying treatment is performed at a temperature of 180 ° C. or higher after applying a coating solution containing a polyester resin and a curing agent on at least one side of the polyester base material. A method for producing a film. 4. The method for producing a polyester-based laminated film according to claim 3, wherein the polyester film substrate coated with the coating solution is stretched in at least one direction.