KR102313134B1 - Multilayer polyester film - Google Patents

Abstract

A laminated polyester film having a resin layer (X) on at least one side of a polyester film, wherein the resin layer (X) contains an acrylic structure (A), a urethane (B), and a naphthalene structure (C), It does not contain a mid structure (G), The change amount (DELTA)R of the spectral reflectance before and behind the boiling process test on the side of the said resin layer (X) is 0 % or more and 2 % or less, The laminated polyester film characterized by the above-mentioned. It has excellent transparency and suppression (visibility) of the iris-like shape (interference fringes) when the hard coating layer is laminated, and the initial adhesion with the hard coating layer, adhesion under high temperature and high humidity (moisture and heat resistance), when immersed in boiling water Provided is a laminated polyester film that is excellent in adhesiveness at the time of boiling (stickiness resistance against boiling) and is further excellent in transparency in hot water when immersed in hot water.

Description

Laminated polyester film {MULTILAYER POLYESTER FILM}

This invention relates to the laminated polyester film which has a resin layer on at least single side|surface of a polyester film. More specifically, transparency and suppression (visibility) of the iris-like pattern (interference fringes) when the hard coat layer is laminated are excellent, and the initial adhesion with the hard coat layer, adhesion under high temperature and high humidity (moisture and heat resistance), Excellent adhesion when immersed in boiling water (hot water resistance) and adhesion after UV irradiation (UV resistance), and further suppression of deterioration of transparency (whitening) when immersed in hot water (hot water transparency) , to provide a laminated polyester film excellent in oligomer suppression properties.

As a representative of a display material, a touch panel provided on a screen of an image display device and giving a predetermined instruction to an information processing device according to a position at which the screen is pressed is known. In many image display apparatuses, including the image display apparatus provided with a touchscreen, the hard-coat film for flaw prevention is provided in the outermost surface. In recent years, opportunities for image display devices such as mobile phones, notebook computers, and personal digital assistants (PDAs) to be used outdoors are increasing. A hard coat film used for an image display device for outdoor use, including car navigation, requires a property (UV adhesion resistance) that does not cause peeling of the hard coat layer and the base film even when exposed to ultraviolet light for a long time.

Moreover, in recent years, the case of using a portable device in a bathroom etc. is also increasing, In the hard-coat film used for portable devices, such as a mobile phone, especially a mobile phone which has a touch panel, adhesiveness under high temperature, high humidity (moisture-resistant adhesiveness) gender) is strongly required. The hard coat film used for such a use is required to have heat-and-moisture adhesiveness that maintains adhesiveness even after being maintained for 250 to 500 hours in an environment of 85° C. and 85% RH. In recent years, boiling-resistant adhesiveness which maintains adhesiveness even after boiling in boiling water (100 degreeC) which is harsher conditions is calculated|required. There is a growing demand for a laminated polyester film that satisfies the adhesiveness under such a harsh environment, has no change in appearance, and is excellent in suppression (visibility) of the iris-like shape (interference fringes) when the hard coating layer is laminated.

In addition, when a high-temperature heat treatment is performed in the processing process of the polyester film, which is a substrate, and when the display device is stored for a long time under high temperature and high humidity, precipitation of oligomers from the polyester film occurs, and the transmittance is lowered and visibility is deteriorated. Since there was a problem, further suppression of precipitation of oligomers (oligomer suppression properties) is demanded.

Therefore, conventionally, the method of providing adhesion|attachment easiness to the surface of a polyester film by various methods is examined. For example, a method of forming an acrylic-modified polyurethane on the film surface as a primer layer (Patent Document 1), a method of forming a copolymer polyester resin and an isocyanate-based crosslinking agent as a primer layer (Patent Document 2), a polyurethane resin and a carbodie Method of forming a mid-type crosslinking agent as a primer layer (patent document 3), a method of forming a primer layer containing an acrylic urethane copolymer resin, an isocyanate type compound, an oxazoline type compound, and a carbodiimide type compound (patent document 4) Moreover, the method (patent document 5) etc. which form the compound and urethane resin which have 30 to 70% of a melamine compound and a naphthalene ring as a primer layer are proposed. In addition, as a method of suppressing oligomer precipitation, a method of forming a coating film on the surface of a resin film using an acrylic modified polyester (Patent Documents 6 and 7), a resin having a specific functional group, mineral oil, and additives such as a crosslinking agent are added to the resin layer Methods (Patent Documents 8 and 9) and the like have been proposed.

Japanese Patent Laid-Open No. 2000-229394 Japanese Patent Laid-Open No. 2003-49135 Japanese Patent Laid-Open No. 2001-79994 International Publication No. 2007/032295 pamphlet Japanese Patent No. 4916339 International Publication No. 2011/122209 pamphlet Japanese Patent Laid-Open No. 2003-012841 Japanese Patent Laid-Open No. 2006-281498 Japanese Patent Laid-Open No. 2002-127621

Although patent document 1 is excellent in initial stage adhesiveness with an ultraviolet curable ink, it is easy to generate|occur|produce the problem, such as adhesiveness in a moist-heat-resistant environment, and boiling-resistant adhesiveness being not obtained.

In addition, in the method described in Patent Document 2, although a certain improvement effect of heat-and-moisture adhesiveness is recognized, adhesion to UV-curable resins, especially solvent-free UV-curable resins constituting the prism lens layer, etc. is insufficient.

In the method described in patent document 3 and patent document 4, although heat-and-moisture adhesiveness besides initial stage adhesiveness was improved, since the refractive index of resin itself was low, there existed a problem that visibility (interference fringe) became insufficient.

In addition, in the method described in Patent Document 5, the decrease in refractive index is suppressed by the compound having a naphthalene ring, visibility is improved, and initial adhesiveness is also improved. In addition, since the method described in Patent Document 5 contains a lot of melamine compounds, there is a problem that process contamination due to volatilization of the melamine compound in the production process becomes a problem, or that the melamine compound generates formaldehyde harmful to the human body by a crosslinking reaction. .

In addition, the method of providing an acrylic-modified polyester having a glass transition point of a certain temperature or higher on the film surface as in Patent Documents 6 and 7 obtains an oligomer precipitation inhibitory effect, but has a problem of adhesion to the laminate.

In addition, when an additive such as mineral oil or a crosslinking agent is used as in Patent Documents 8 and 9, the additive itself bleeds out over time on the surface of the resin layer during formation of the resin layer or during film formation, as in the case of deposition of oligomers, whitening of the film There was a problem of causing contamination, etc. in the film conveyance process.

As described above, in the prior art, suppression of interference fringes (visibility), heat-and-moisture adhesiveness, boiling-resistant adhesiveness, and UV-resistance could not all be satisfied. Moreover, in the prior art, it was not able to satisfy|fill hot water transparency and oligomer suppression property.

Therefore, it is an object of the present invention to solve the above-mentioned drawbacks, and particularly excellent in wet and heat resistance, boiling resistance and UV resistance as well as initial adhesiveness, and also laminated poly which is excellent in hot water transparency and oligomer suppression properties. It aims at providing an ester film. Another object of the present invention is to provide a laminated polyester film having the above-described excellent properties even when a small amount or no melamine compound is contained.

The laminated polyester film which concerns on this invention has the following structure.

(1) A laminated polyester film having a resin layer (X) on at least one side of a polyester film, wherein the resin layer (X) includes an acrylic structure (A), a urethane structure (B), and a naphthalene structure (C) and does not contain a carbodiimide structure (G), and the amount of change ΔR of the spectral reflectance before and after the boiling treatment test on the resin layer (X) side is 0% or more and 2% or less.

(2) The surface zeta potential of the said resin layer (X) is -20 mV or more, The laminated polyester film characterized by the above-mentioned.

(3) The minimum value of the spectral reflectance in the wavelength range of 450 nm or more and 650 nm or less of wavelength on the side of the said resin layer (X) is 4.5 % or more and 6.0 % or less, The laminated polyester film as described in (1) or (2) characterized by the above-mentioned.

(4) The resin layer (X) is an acrylic/urethane copolymer resin (a), a polyester resin having a naphthalene skeleton (b), an isocyanate compound (c), and an oxazoline compound (d) using a coating composition containing It is a formed layer, The laminated polyester film in any one of (1)-(3) characterized by the above-mentioned.

(5) The dispersion index of the aggregate containing the acrylic urethane copolymer resin (a) in the resin layer (X) is 5 or less, and the proportion of the acrylic urethane copolymer resin (a) in the coating composition is 3 wt% or more The laminated polyester film as described in (4) characterized by the above-mentioned.

(6) The polyester resin (b) is a co-polyester resin containing 1 to 30 mol% of an aromatic dicarboxylic acid component containing a sulfonic acid metal base based on the total dicarboxylic acid component of the polyester. The laminated polyester film in any one of said (4) or (5).

(7) Said polyester resin (b) contains the diol component represented by following formula (1), The laminated polyester film in any one of (4)-(6) characterized by the above-mentioned.

(wherein, X ¹ , X ² : represents -(C _n H _2n O) _m -H (an integer of n=2 or more and 4 or less, m=1 or more and 15 or less))

(8) In any one of (4) to (7), characterized in that the solid content weight ratio of the acrylic/urethane copolymer resin (a) and the polyester resin (b) in the coating composition is 40/60 to 5/95. The laminated polyester film described.

(9) In the above coating composition, when the total of the solid content of the acrylic/urethane copolymer resin (a) and the polyester resin (b) is 100 parts by weight, 3 to 20 parts by weight of the isocyanate compound (c) by the solid content weight , The laminated polyester film according to (8), characterized by containing 20 to 50 parts by weight of the oxazoline compound (d) by solid content weight.

(10) When the total weight of the solid content of the acrylic/urethane copolymer resin (a) and the polyester resin (b) is 100 parts by weight, the coating composition further contains 5 to 30 parts by weight of the melamine compound (e) The laminated polyester film as described in (9) characterized by the above-mentioned.

The laminated polyester film of the present invention has excellent transparency and suppression (visibility) of an iris-like pattern (interference fringes) when the hard coating layer is laminated, as well as excellent initial adhesion with the hard coating layer, and adhesion under high temperature and high humidity (resistance to moisture and heat). Adhesiveness), the adhesion when immersed in boiling water (the boiling water adhesion), the adhesion after UV irradiation (UV resistance), and furthermore, the deterioration of transparency when immersed in hot water (whitening) suppression ( It exhibits the effect that it is excellent also in hot water transparency) and oligomer suppression property.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows typically a laminated polyester film with a large dispersion index.
2 is a cross-sectional view schematically showing a laminated polyester film having a small dispersion index.
3 is a cross-sectional view schematically showing a laminated polyester film having a small dispersion index.
It is a figure which shows typically the surface which performs cross-sectional observation of a laminated polyester film.

Hereinafter, the laminated polyester film of this invention is demonstrated in detail.

The laminated polyester film of this invention has a polyester film used as a base material, It has a resin layer (X) in at least single side|surface of the polyester film.

(1) polyester film

In the present invention, the polyester constituting the polyester film serving as the substrate is a generic term for polymers having an ester bond as a main bond chain of the main chain. As the preferred polyester, at least one constituent resin selected from ethylene terephthalate, ethylene-2,6-naphthalate, butylene terephthalate, propylene terephthalate and 1,4-cyclohexanedimethylene terephthalate is used as the main constituent resin. can be heard These constituent resins may be used alone or in combination of two or more. The intrinsic viscosity of the aforementioned polyester (measured in o-chlorophenol at 25°C) is preferably in the range of 0.4 to 1.2 dl/g, more preferably in the range of 0.5 to 0.8 dl/g. is suitable for

In addition, in the polyester, various additives, for example, antioxidants, heat-resistant stabilizers, weathering stabilizers, ultraviolet absorbers, organic lubricants, pigments, dyes, organic or inorganic fine particles, fillers, antistatic agents, nucleating agents and crosslinking agents, etc. have their properties It may be added to such an extent that it does not deteriorate.

Moreover, it is preferable to use a biaxially-oriented polyester film as said polyester film. Here, "biaxial orientation" means showing a pattern of biaxial orientation by wide-angle X-ray diffraction. A biaxially oriented polyester film can be obtained by generally extending|stretching a polyester sheet in an unstretched state about 2.5 to 5 times, respectively in the sheet longitudinal direction and the width direction, and performing heat processing after that.

In addition, as for the polyester film, the laminated structure of two or more layers may be sufficient as polyester film itself. Preferred laminated structures in the polyester film of the present invention include, for example, a composite film having an inner layer portion and a surface layer portion, in which a layer containing particles only in the surface layer portion without substantially containing particles in the inner layer portion is formed. can Further, the polyester constituting the inner layer portion and the surface layer portion may be of the same type or different types.

The thickness of the polyester film is not particularly limited and is appropriately selected depending on the use or type, but from the viewpoint of mechanical strength and handling properties, it is usually preferably 10 to 500 µm, more preferably 38 to 250 µm, and most preferably preferably 75 to 150 μm. Moreover, the composite film by co-extrusion may be sufficient as a polyester film, and the film which laminated|attached the obtained film by various methods may be sufficient as it.

(2) Resin layer (X)

The laminated polyester film of the present invention is a laminated polyester film having a resin layer (X) on at least one side of the polyester film, wherein the resin layer (X) has an acrylic structure (A), a urethane structure (B) and a naphthalene structure ( Laminated polyester comprising C) and not including the carbodiimide structure (G), wherein the amount of change ΔR of the spectral reflectance before and after the boiling treatment test on the resin layer (X) side is 0% or more and 2% or less it's a film

The laminated polyester film of the present invention has excellent transparency and suppression (visibility) of an iris-like pattern (interference fringes) when a hard coat layer is laminated, and also has excellent initial adhesion with the hard coat layer, and adhesion under high temperature and high humidity (resistance to moisture and heat). Adhesiveness), the adhesion when immersed in boiling water (the boiling water adhesion), the adhesion after UV irradiation (UV resistance), and furthermore, the deterioration of transparency when immersed in hot water (whitening) suppression ( It is excellent in hot water transparency) and oligomer suppression properties.

The resin layer (X) of the present invention includes an acrylic structure (A) and a urethane structure (B), so that initial adhesion with the hard coat layer, heat-and-moisture adhesion, boiling-resistance adhesion, UV resistance and general-purpose adhesion can be given In addition, by including the naphthalene structure (C), which is a high refractive structure, in the resin layer (X), the refractive index of the resin layer (X) can be an intermediate value between the refractive index of the polyester film and the refractive index of a general hard coating, so hard Interference fringes when a coating layer is laminated can be suppressed. On the other hand, by removing the carbodiimide structure (G) from the resin layer (X), it is possible to maintain the transparency of hot water when immersed in hot water.

The laminated polyester film of the present invention is a laminated polyester film having a resin layer (X) on at least one side of the polyester film, wherein the resin layer (X) is a polyester having an acrylic/urethane copolymer resin (a) and a naphthalene skeleton It is preferable that it is a layer formed using the coating composition containing resin (b), an isocyanate compound (c), and an oxazoline compound (d).

Here, when the change amount ΔR of the spectral reflectance before and after the boiling treatment test in the present invention performs a boiling treatment test in which the laminated polyester film is immersed in boiling water (100°C) for 5 hours, the resin layer of the laminated polyester film It shows the absolute value (%) of the change amount of the spectral reflectance before and behind the boiling process test when the spectral reflectance is measured from the (X) side.

In addition, the spectral reflectance (%) before a boiling process test, and the spectral reflectance (%) after a boiling process test are calculated|required based on "(8) evaluation method of the amount of change ΔR of the spectral reflectance before and after the boiling process test" mentioned later. ΔR is the absolute value of the amount of change obtained by subtracting the average spectral reflectance (%) after the boiling treatment test from the spectral reflectance (%) before boiling test treatment (ΔR=|average spectral reflectance before boiling test treatment - average spectral reflectance after boiling test treatment |) ( %) as

The change amount ΔR of the spectral reflectance before and after the boiling treatment test is required to be 0% or more and 2% or less, more preferably 0% or more and 1.8% or less, still more preferably 0% or more and 1.5% or less, and the closer to 0%, the more preferable do.

When the amount of change ΔR of the spectral reflectance before and after the boiling treatment test when measured from the resin layer (X) side is 0% or more and 2% or less, the laminated polyester film of the present invention is transparency and iris when a hard coat layer is laminated Excellent in suppression (visibility) of phase pattern (interference fringes), and excellent initial adhesion with the hard coating layer, heat-and-moisture adhesion, and surprisingly, adhesion when immersed in boiling water (bitter-resistant adhesiveness) can manifest.

The reason is assumed as follows. The change of the spectral reflectance when measured from the resin layer (X) side occurs with the change of the refractive index by the composition of the resin layer (X) changing. Therefore, that a spectral reflectance changes before and behind a boiling process test means that the refractive index of resin layer (X) is changing by a boiling process test. That is, it has shown that the composition of the resin layer (X) changed. As a composition change of resin layer (X) by a boiling treatment test, the outflow to boiling water of the composition component of resin layer (X), and penetration into resin layer (X) of boiling water is considered. When the change amount ΔR of the spectral reflectance before and after the boiling treatment test is 0% or more and 2% or less, the composition change of the resin layer (X) by the boiling treatment test is small, so even after immersion under high temperature, high humidity or boiling water, excellent moist heat resistance adhesion It is possible to express the adhesiveness and boiling-resistance.

On the other hand, when the change amount ΔR of the spectral reflectance before and after the boiling treatment test exceeds 2%, since the composition change of the resin layer (X) by the boiling treatment test is large, the wet-and-heat adhesiveness and boiling-resistant adhesiveness fall.

In the present invention, as a method of forming the resin layer (X) in which the change amount ΔR of the spectral reflectance before and after the boiling treatment test is 0% or more and 2% or less, the resin layer (X) containing the acrylic urethane copolymer resin (a) By making the dispersion index of an aggregate into 5 or less, the change amount (DELTA)R of the spectral reflectance before and behind a boiling process test can form the resin layer (X) used as 0 % or more and 2 % or less.

Moreover, it is preferable that the resin layer (X) of this invention has a surface zeta potential of -20 mV or more.

By setting the surface zeta potential of the resin layer (X) to -20 mV or more, the polarity of the surface of the resin layer (X) can be reduced, and penetration and adsorption of water into the resin layer (X) can be suppressed. It can express boiling-resistant adhesiveness.

In addition, the method for adjusting the surface zeta potential of resin layer (X) to -20 mV or more is not specifically limited. As a method of adjusting the surface zeta potential, a method of adjusting the composition ratio of the structure or chemical structure of the resin contained in the resin layer (X), a discharge treatment such as corona treatment, plasma treatment, physical treatment such as frame treatment, acid treatment or alkali treatment A method of performing chemical treatment such as treatment and introducing anionic functional groups such as carboxyl groups and hydroxyl groups to the surface of the resin layer (X), and a method of performing discharge treatment such as corona treatment and plasma treatment to the resin layer (X) etc. are preferable.

The laminated polyester film of the present invention is a coating material in which the resin layer (X) contains an acrylic/urethane copolymer resin (a), a polyester resin (b) having a naphthalene skeleton, an isocyanate compound (c), and an oxazoline compound (d) It is a layer formed using the composition, and it is preferable that it is a laminated polyester film whose dispersion index of the aggregate containing the acrylic urethane copolymer resin (a) of the said layer (X) is 5 or less, and it is more preferable that it is 3 or less. The dispersion index in the present invention refers to an aggregate containing an acrylic urethane copolymer resin (a) having a size observed in a specific area of 40 nm or more when the cross section of the resin layer (X) is observed using a transmission electron microscope (TEM). Indicates the average number. The magnification was 20,000 times, and the number of aggregates having a size of 40 nm or more containing the acrylic urethane copolymer resin (a) observed in the viewing area (Z direction × X direction: 500 nm × 1200 nm) was measured. The number of the obtained aggregates is converted into the number per ^{predetermined area (120000 nm 2 ) by the following formula.}

(the number of aggregates having an observed size of 40 nm or more) × 120000/area occupied by the resin layer (X) in the viewing area

This observation was performed with respect to 10 visual fields, the average number of aggregates containing the acrylic urethane copolymer resin (a) present per predetermined area was computed, and the value which rounded off the number of 1st decimal places was made into the dispersion index. Here, the size of the aggregate indicates the maximum diameter of the aggregate (that is, the long diameter of the aggregate and represents the longest diameter in the aggregate), and also in the case of an aggregate having a cavity therein, it also indicates the maximum diameter of the aggregate.

The variance index represents an integer greater than or equal to 0. It is preferable that the dispersion index in this invention is 5 or less, More preferably, it is 3 or less.

In order to confirm the dispersion index of the resin layer (X), it can be determined by observing the cross-sectional structure of the layer (X) using a transmission electron microscope (TEM).

First, cross-sectional observation of the resin layer (X) is demonstrated.

With respect to the laminated polyester film, a sample of the cross section of the layer (X) is prepared by _{RuO 4 dyeing ultra-thin film sectioning method.} When the cross section of the obtained sample is observed with respect to the viewing area (Z direction × X direction: 500 nm × 1200 nm) observed at an acceleration voltage of 100 kV and a magnification of 20,000 times, the structure shown in FIGS. 1 to 3 can be confirmed, for example.

Here, cross-sectional observation of the resin layer (X) means cross-sectional observation of the XZ plane in FIG. 4 . Here, _{dyeing with RuO 4} can be performed on a portion having an acrylic skeleton.

For example, the resin layer (X) performs sample preparation similarly to a polyester resin (b) having a naphthalene skeleton, and a laminated polyester film containing only an isocyanate compound (c) and an oxazoline compound (d), and observe the cross section because of the case, it does not contain an acrylic-urethane copolymer resin (a) to be dyed by RuO ₄ is not observed black portion. On the other hand, when the resin layer (X) performs sample preparation similarly to the laminated polyester film containing only the acrylic urethane copolymer resin (a) and observes the cross section, the acrylic urethane copolymer resin (a) dyed with _{RuO 4} ), the entire resin layer (X) becomes a black portion. From this result, it can be judged that a black part is a part containing an acrylic urethane copolymer resin (a).

When the layer (X) has a sea-island structure as shown in FIG. 1 , compared to the structures of FIGS. 2 and 3 , the islands of the black portion (eg, acrylic urethane copolymer resin) in the thickness direction of the layer (X) As the number of , the variance index increases. On the other hand, in the case of the structures of FIGS. 2 and 3 , the dispersion index decreases because the number of islands in the black portion is small.

When the dispersion index observed by the above-described method exceeded 5, it was judged that the resin layer (X) did not form a uniform dispersion structure. On the other hand, when the dispersion index was 5 or less, it was judged that the resin layer (X) had a uniform dispersion structure.

The resin layer (X) is a layer formed using a coating composition comprising an acrylic urethane copolymer resin (a), a polyester resin having a naphthalene skeleton (b), an isocyanate compound (c), and an oxazoline compound (d), It is preferable that the dispersion index of the aggregate containing the acrylic urethane copolymer resin (a) of the said layer (X) is 5 or less, More preferably, it is 5 or less, Furthermore, 2 or less are preferable. By setting it as this range, the laminated polyester film of this invention is more excellent in transparency and suppression (visibility) of an iris-like pattern (interference fringe) when a hard-coat layer is laminated|stacked, and initial stage adhesiveness with a hard-coat layer, heat-and-moisture resistance It is more excellent in adhesiveness, and since it can also express surprisingly the adhesiveness when immersed in boiling water (heat-resistant adhesiveness), and the adhesiveness after UV irradiation (UV-resistance adhesiveness), it is preferable.

The reason is assumed as follows. When the acrylic urethane copolymer resin (a) forms a uniform dispersion structure having a dispersion index of 5 or less as in FIGS. It is also distributed on the surface. Moreover, the isocyanate compound (c) and the oxazoline compound (d) which are excellent in adhesiveness with a hard-coat layer are distributed also on the said layer (X) surface similarly. As a result, the interaction between the hard coat layer and the layer (X) increases, and the adhesion with the hard coat layer is significantly improved, and when a force to peel the laminated hard coat layer is applied, the adhesion in the plane is uniform. In general, the stress is dispersed without concentration, and excellent heat-and-moisture adhesion, boiling-resistant adhesion, and UV-resistance adhesion can be expressed. In addition, when the acrylic urethane copolymer resin (a) forms a uniform dispersed structure in the resin layer (X), the acrylic urethane copolymer resin (a) with a low refractive index does not collect locally, so the layer ( The refractive index in X) also becomes uniform, and the said layer (X) which has a uniform refractive index in the thickness direction can be formed. As a result, when a hard-coat layer is laminated|stacked, since it is excellent also in suppression (visibility) of an iris-like pattern (interference fringe), it is preferable.

On the other hand, when the dispersion index exceeds 5, a decrease in transparency, heat-and-moisture adhesiveness, boiling-resistant adhesiveness, and UV-resistance adhesiveness occur due to poor dispersion of the mutual resin.

In the present invention, as a method for forming a uniform dispersion structure having a dispersion index of 5 or less in the resin layer (X), for example, as described below, the polyester resin (b) having a naphthalene skeleton is a metal sulfonic acid. Each resin of (a) to (d) in the coating composition using a copolymerized polyester resin containing 1 to 30 mol% of an aromatic dicarboxylic acid component containing a base with respect to the total dicarboxylic acid component of the polyester The resin layer (X) can form a structure with a dispersion index of 5 or less by making the ratio of .

Moreover, as for the laminated polyester film of this invention, it is preferable that the minimum values of the spectral reflectance in the wavelength range of 450 nm or more and 650 nm or less on the side of the resin layer (X) are 4.5 % or more and 6.0 % or less.

The reason is that if the absorption wavelength of human photoreceptors is in the range of 450 nm or more and 650 nm or less, and the minimum value of the spectral reflectance in this wavelength range is 4.5% or more and 6.0% or less, the iris-like shape (interference non-uniformity) when the hard coating layer is laminated is Because it is difficult to see.

In the present invention, as a method for forming a laminated polyester film in which the minimum value of the spectral reflectance in the wavelength range of 450 nm or more and 650 nm or less on the side of the resin layer (X) is 4.5% or more and 6.0% or less, for example, a naphthalene skeleton The polyester resin (b) having a co-polyester resin containing 1 to 30 mol% of an aromatic dicarboxylic acid component containing a sulfonic acid metal base, based on the total dicarboxylic acid component of the polyester, is used in the coating composition. By making the ratio of each resin of (a) to (d) into a certain range, the minimum value of the spectral reflectance in the wavelength range of 450 nm or more and 650 nm or less on the side of the layer (X) is 4.5% or more and 6.0% or less laminated polyester A film can be formed.

As the reason, for example, the polyester resin (b) having a naphthalene skeleton contains an aromatic dicarboxylic acid component containing a sulfonic acid metal base in an amount of 1 to 30 mol% based on the total dicarboxylic acid component of the polyester. When an ester resin is used, compatibility with acryl-urethane copolymer resin (a) and other resin improves, and it becomes possible to form a uniform dispersed structure. As a result, the refractive index in the resin layer (X) is also uniform, and the minimum value of the spectral reflectance in the wavelength range of 450 nm or more and 650 nm or less on the side of the resin layer (X) is 4.5% or more and 6.0% or less to form a laminated polyester film can do. By setting it as the range of this reflectance, when the hard-coat layer is laminated|stacked, since suppression (visibility) of an iris-like pattern (interference fringe) becomes possible from the principle of optical interference, it is preferable.

The reason will be described in detail below. Suppression of the iris-like shape becomes possible by controlling the refractive index and the film thickness of the resin layer (X). When the refractive index of resin layer (X) is made into the refractive index of the value of the rising average of the refractive index of the polyester film which is a base material, and the hard-coat layer laminated|stacked, an iris-like pattern can be suppressed most. For example, when the hard coat layer contains an acrylic resin and the polyester film as the base material contains polyethylene terephthalate, the refractive index of the hard coat layer is 1.52, and the refractive index of the polyester film as the base material is 1.65, so the optimum for suppressing the iris shape The refractive index of the phosphorus resin layer (X) is 1.58, which is a rising average thereof. Since there is a correlation between the refractive index of the coating film and the reflectance in the wavelength range of 450 nm or more and 650 nm or less, the minimum value of the spectral reflectance in the wavelength range of 450 nm or more and 650 nm or less of the resin layer (X) is 4.5% or more and 6.0% or less. By setting it as a polyester film, suppression of an iris-shaped pattern becomes possible.

In addition, in the laminated polyester film of the present invention, a coating composition having a solid content weight ratio of 40/60 to 5/95 of the acrylic/urethane copolymer resin (a) and the polyester resin (b) is applied to at least one side of the polyester film, If it is a laminated polyester film obtained by forming the formation layer (X), since the adhesiveness of a laminated polyester film and a hard-coat layer becomes favorable, it is preferable. In addition, when the total weight of the solid content of the acrylic/urethane copolymer resin (a) and the polyester resin (b) in the coating composition is 100 parts by weight, 3 to 20 parts by weight of the isocyanate compound (c) by weight of the solid content, oxazoline If it is a laminated polyester film obtained by forming a resin layer (X) by applying a coating composition containing 20 to 50 parts by weight of the compound (d) by solid content weight, the acrylic/urethane copolymer resin (a) of the resin layer (X) It is preferable because the dispersion index can form a laminated polyester film having a uniform dispersion structure of 5 or less, and the heat-and-moisture adhesiveness, boiling resistance, and UV resistance of the laminated polyester film are improved.

As a result, the resin layer has high transparency, adhesiveness with the hard coating layer, heat-and-moisture adhesiveness, boiling-resistance adhesiveness, UV-resistance resistance, and furthermore, when the hard coating layer is laminated, excellent suppression of interference fringes (visibility) is expressed. it becomes possible

Moreover, the laminated polyester film of this invention is excellent also in transparency deterioration (whitening) suppression at the time of being immersed in hot water (hot water transparency). Hot water transparency can be evaluated by film haze change amount (DELTA)Hz before and behind a boiling process test. Film haze change amount (DELTA)Hz before and behind a boiling process test shows the change amount of the film haze before and behind the boiling process test which immerses a laminated polyester film in 100 degreeC hot water. Specifically, the value obtained by subtracting the haze value of the laminated polyester film before the boiling treatment test from the haze value of the laminated polyester film after the boiling treatment test is the amount of change in film haze before and after the boiling treatment test ΔHz (ΔHz = film haze - boiling after the boiling treatment) film haze before the treatment test) is shown. A detailed measurement method will be described later. In this invention, let the film whose film haze change amount (DELTA)Hz before and behind a boiling process test is less than 5.0 % as a film excellent in hot water transparency.

By making film haze change amount (DELTA)Hz before and behind a boiling treatment test less than 5.0 %, even when it uses for a long time in harsh environments, such as high temperature and high humidity, it can be set as the laminated polyester film which can suppress deterioration of transparency. As for the film haze change amount (DELTA)Hz before and behind a boiling process test, it is more preferable that it is less than 4.5 %. As a method for obtaining the laminated polyester film used as film haze change amount ΔHz before and after the boiling treatment test is less than 5.0%, for example, using an oxazoline compound (d) in the coating composition for forming the resin layer (X), paint The method of making the ratio of resin or compound of (a)-(d) in a composition into arbitrary fixed ranges, the method of combining these methods, etc. are mentioned.

As the reason, the following mechanism is assumed. When the boiling process test was performed with respect to the laminated polyester film which has a resin layer from previous examination, a fine void will generate|occur|produce on the resin layer surface, and it confirmed that the haze of a laminated polyester film rises. It was thought that the unreacted component of the crosslinking component contributing to adhesiveness flows out by the boiling process test at the point that a haze rose and adhesiveness fell with the increase of this void formation amount. When the oxazoline compound (d) is used, compatibility with the polyester resin (b) having a naphthalene skeleton and other resins is improved, it is possible to form a resin layer having a uniform dispersed structure, and in particular, the degree of crosslinking is reduced. Since a high resin layer could be formed, an oxazoline compound or its unreacted component was hard to flow out in a boiling process test, As a result, generation|occurrence|production of a void was suppressed and it thought that haze change amount could be suppressed significantly.

Moreover, the laminated polyester film of this invention is excellent also in precipitation suppression (oligomer suppression property) of an oligomer under high temperature. The oligomer suppression property can be evaluated by the amount of change in film haze (ΔHz after heating) before and after high-temperature heat treatment. The amount of change in film haze (after heating ΔHz) before and after high-temperature heat treatment heat-processes a laminated polyester film at 150 degreeC, and shows the change amount of the film haze before and behind that. Specifically, the value obtained by subtracting the haze value of the laminated polyester film before heat treatment from the haze value of the laminated polyester film after heat treatment is the amount of change in film haze before and after high temperature heat treatment (ΔHz after heating) (ΔHz after heating = after heat treatment) Film haze - film haze before heat treatment) is shown. A detailed measurement method will be described later. In the present invention, a film having an amount of change in film haze before and after heat treatment (ΔHz after heating) of less than 2.5% is considered to be a film excellent in oligomer suppression property.

By setting the amount of change in film haze before and after heat treatment (ΔHz after heating) to less than 2.5%, even when high-temperature heat treatment is performed in the processing step of the polyester film as a base material, deterioration of transparency and deterioration of visibility can be suppressed. can be done with It is more preferable that the amount of change in film haze before and after heat treatment (ΔHz after heating) is less than 2.0%. As a method for obtaining a laminated polyester film in which the amount of change in film haze before and after heat treatment (ΔHz after heating) is less than 2.5%, for example, an oxazoline compound (d) is used in the coating composition for forming the resin layer (X) and a method of making the ratio of the resin or compound of (a) to (d) in the coating composition within an arbitrary fixed range, and a method of combining these methods, and the like.

As the reason, the following mechanism is assumed. The oligomer inhibitory property is expressed when the polyester resin (b) having a naphthalene skeleton and the oxazoline compound (d) react and crosslink. When the oxazoline compound (d) is used in the coating composition for forming the resin layer (X), or the ratio of the resins or compounds of (a) to (d) in the coating composition is set to an arbitrary fixed range, a poly having a naphthalene skeleton Since the ester resin (b) and the oxazoline compound (d) react quickly and a resin layer with a high degree of crosslinking can be formed, the oligomer becomes difficult to diffuse in high-temperature heat treatment, and the amount of change in film haze can be significantly suppressed. think it will

Here, when a carbodiimide compound (g) containing, for example, the carbodiimide structure (G) represented by Formula (2) is added to the coating composition, the polyester resin (b) having a naphthalene skeleton; Since the reaction of the isocyanate compound (c), the oxazoline compound (d), and the melamine compound (e) is inhibited, a resin layer with a high degree of crosslinking cannot be formed, and the oligomer suppression property is deteriorated, which is not preferable.

Hereinafter, the acrylic urethane copolymer resin (a) used in the laminated polyester film of the present invention, the polyester resin (b) having a naphthalene skeleton, the isocyanate compound (c), the oxazoline compound (d), and the melamine compound (e) will be described.

(1) Acrylic-urethane copolymer resin (a)

The acrylic urethane copolymer resin (a) in the laminated polyester film of this invention will not be specifically limited if it is resin by which the acrylic resin and the urethane resin were copolymerized.

The acrylic resin used by this invention shows resin obtained by copolymerizing the acrylic monomer mentioned later and another type monomer as needed by the polymerization method of well-known acrylic resins, such as emulsion polymerization and suspension polymerization.

As the acrylic monomer used for the acrylic urethane copolymer resin (a), for example, an alkyl acrylate (as an alkyl group, methyl, ethyl, n-propyl, n-butyl, isobutyl, t-butyl, 2-ethylhexyl, cyclohexyl, etc.) , alkyl methacrylate (as an alkyl group, methyl, ethyl, n-propyl, n-butyl, isobutyl, t-butyl, 2-ethylhexyl, cyclohexyl, etc., 2-hydroxyethyl acrylate, 2-hydroxyethyl meth Hydroxyl group-containing monomers such as acrylate, 2-hydroxypropyl acrylate and 2-hydroxypropyl methacrylate, acrylamide, methacrylamide, N-methylmethacrylamide, N-methylacrylamide, N-methylolacrylamide amide, N-methylmethacrylamide, N,N-dimethylolacrylamide, N-methoxymethylacrylamide, N-methoxymethylmethacrylamide, N-butoxymethylacrylamide, N-phenylacrylamide, etc. Amide group-containing monomers, amino group-containing monomers such as N,N-diethylaminoethyl acrylate and N,N-diethylaminoethyl methacrylate, glycidyl groups such as glycidyl acrylate and glycidyl methacrylate and monomers containing a carboxyl group or a salt thereof, such as a containing monomer, acrylic acid, methacrylic acid, and salts thereof (sodium salt, potassium salt, ammonium salt, etc.).

The acrylic resin is obtained by polymerization using one or two or more types of acrylic monomers, but when monomers other than the acrylic monomer are used together, the proportion of the acrylic monomer in the total monomers is 50% by weight or more, and further 70% by weight or more. It is preferable from a viewpoint of adhesiveness.

In addition, the urethane resin used by this invention shows resin obtained by making a polyhydroxy compound and a polyisocyanate compound react by well-known polymerization methods, such as emulsion polymerization and suspension polymerization, of a urethane resin.

Examples of the polyhydroxy compound include polyethylene glycol, polypropylene glycol, polyethylene propylene glycol, polytetramethylene glycol, hexamethylene glycol, tetramethylene glycol, 1,5-pentanediol, diethylene glycol, triethylene glycol, polycapro. Lactone, polyhexamethylene adipate, polyhexamethylene sebacate, polytetramethylene adipate, polytetramethylene sebacate, trimethylolpropane, trimethylolethane, pentaerythritol, polycarbonate diol, glycerin, etc. are mentioned. .

Examples of the polyisocyanate compound include hexamethylene diisocyanate, diphenylmethane diisocyanate, tolylene diisocyanate, isophorone diisocyanate, an adduct of tolylene diisocyanate and trimethylene propane, an adduct of hexamethylene diisocyanate and trimethylolethane, etc. is available.

When applying to the in-line coating method mentioned later as a method of forming the resin layer (X), it is preferable that the acryl-urethane copolymer resin (a) melt|dissolves or disperse|distributes in water. As a method of improving the affinity to water of an acrylic urethane copolymer resin, using a carboxylic acid group containing polyhydroxy compound or hydroxyl group containing carboxylic acid is mentioned as one of polyhydroxy compounds, for example. As a carboxylic acid group containing polyhydroxy compound, dimethylol propionic acid, dimethylol butyric acid, dimethylol valeric acid, trimellitic acid bis(ethylene glycol) ester etc. can be used, for example. As hydroxyl-containing carboxylic acid, 3-hydroxypropionic acid, gamma -hydroxybutyric acid, p-(2-hydroxyethyl) benzoic acid, malic acid, etc. can be used, for example.

Moreover, the method of introduce|transducing a sulfonic acid base into a urethane resin is mentioned as another method of improving the affinity to the water of acryl-urethane copolymer resin. For example, a prepolymer is produced from a polyhydroxy compound, a polyisocyanate compound, and a chain extender, and a compound having an amino or hydroxyl group capable of reacting with a terminal isocyanate group and a sulfonic acid base or a sulfate half ester base in the molecule is added thereto; It is a method of obtaining a urethane resin having a sulfonic acid base or a sulfate half ester base in the molecule. As the compound having an amino or hydroxyl group capable of reacting with a terminal isocyanate group and a sulfonic acid base, for example, aminomethanesulfonic acid, 2-aminoethanesulfonic acid, 2-amino-5-methylbenzene-2-sulfonic acid, β-hydroxyethanesulfonic acid sodium , a propane sultone of an aliphatic primary amine compound, a butane sultone addition product, and the like, and preferably a propane sultone adduct of an aliphatic primary amine compound.

An acrylic urethane copolymer resin (a) uses an acrylic resin as a skin layer, and if it is an acrylic urethane copolymer resin which uses a urethane resin as a core layer, since it is excellent in adhesiveness with a hard-coat layer, it is preferable. Among them, it is preferable that the core layer containing the urethane resin is not completely covered by the skin layer containing the acrylic resin, and the core layer is exposed. When the core layer is completely covered by the skin layer, the resin layer (X) is in a surface state having only the characteristics of the acrylic resin, and it is difficult to obtain a surface state having the characteristics of the urethane resin derived from the core layer. It is unpreferable from the point of adhesiveness with a coating layer. On the other hand, the state in which the core layer is not covered by the skin layer, that is, the state in which both are separated is a state in which an acrylic resin and a urethane resin are mixed. Then, in general, the acrylic resin having a small surface energy of the resin is selectively coordinated to the air-side surface of the resin layer (X). As a result, since the surface of the resin layer (X) has only the characteristics of an acrylic resin, it is unpreferable from the point of adhesiveness with a hard-coat layer.

One example of obtaining the acrylic urethane copolymer resin (a) which has a core skin structure is shown. First, a first stage emulsion polymerization is performed using a urethane resin monomer, an emulsifier, a polymerization initiator, and an aqueous solvent forming a core portion of the polymer resin. Next, after the 1st stage emulsion polymerization is substantially complete|finished, the acrylic monomer which forms a skin part and a polymerization initiator are added, and 2nd stage emulsion polymerization is performed. By this two-step reaction, the acrylic urethane copolymer resin which has a core skin structure can be obtained. In order to make the resulting copolymer resin a two-layer structure of a core layer and a skin structure, the emulsifier in the second stage emulsion polymerization is limited to an amount that does not form a new core, and the urethane resin formed in the first stage emulsion polymerization is included. A method for allowing polymerization to proceed on the surface of the core is useful.

Although the following method is mentioned as for the manufacturing method of an acrylic urethane copolymer resin (a), it is limited to what is obtained by this method, and is not interpreted. For example, a small amount of a dispersant and a polymerization initiator are added to the aqueous dispersion of the urethane resin, and the acrylic monomer is added gradually while maintaining the temperature at a constant temperature while stirring. After that, if necessary, the temperature is increased, the reaction is continued for a certain period of time, polymerization of the acrylic monomer is completed, and an aqueous dispersion of the acrylic urethane copolymer resin is obtained.

It is preferable that content of the acrylic urethane copolymer resin (a) in a coating composition is 3 weight% or more with respect to the total weight of resin solid content in a coating composition. When content of an acrylic urethane copolymer resin (a) is less than 3 weight%, adhesiveness and suppression of an interference fringe may not be compatible. 3 weight% or more and 25 weight% or less are preferable with respect to the total weight of resin solid content in a coating composition, and it is more preferable that it is 4 weight% or more and 20 weight% or less. Especially preferably, it is 5 weight% or more and 10 weight% or less.

20 degreeC or more is preferable and, as for the glass transition temperature (a glass transition temperature is called "Tg" hereafter) of the acrylic resin in an acrylic urethane copolymer resin (a), it is more preferable that it is 40 degreeC or more. Since the blocking property at the time of room temperature storage improves that Tg of an acrylic resin is 20 degreeC or more, it is preferable.

Further, the ratio of the acrylic resin to the urethane resin in the acrylic/urethane copolymer resin (a) (acrylic resin/urethane resin) is preferably 10/90 to 70/30, more preferably 20/80 to 50/50 by weight. do. When it becomes outside this range, the adhesiveness of a laminated polyester film and a hard-coat layer may deteriorate. The weight ratio of an acrylic resin and a urethane resin can be made into a desired value by adjusting the compounding quantity of the raw material at the time of manufacture of an acrylic urethane copolymer resin (a).

Moreover, since the adhesiveness of a laminated polyester film and a hard-coat layer becomes favorable if the solid content weight ratio of the acrylic urethane copolymer resin (a) and the polyester resin (b) in a coating composition is 40/60-5/95, it is preferable. do. More preferably, they are 30/70 - 10/90.

(2) polyester resin having a naphthalene skeleton (b)

The polyester resin (b) having a naphthalene skeleton in the present invention is a resin having a naphthalene skeleton in a polyester resin having an ester bond as a main bond chain of the main chain.

As a method for obtaining a polyester resin having a naphthalene skeleton, for example, a diol component or a polyhydric hydroxyl group component having two or more hydroxyl groups introduced as substituents into the naphthalene ring, or a carboxylic acid group or two or more ester-forming derivatives of carboxylic acid There is a method in which the introduced dicarboxylic acid component or polyhydric carboxylic acid component is used as a raw material for a polyester resin. It is preferable to obtain the polyester resin which has a naphthalene skeleton using the dicarboxylic acid component which introduce|transduced two carboxylic acid groups into the naphthalene ring from a stability viewpoint of a polyester resin as a polyester resin raw material. Examples of the naphthalene skeleton into which two carboxylic acid groups have been introduced include 2,6-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, and 1,5-naphthalenedicarboxylic acid. Aromatic dicarboxylic acids such as carboxylic acid and 2,7-naphthalenedicarboxylic acid, furthermore, 2,6-naphthalenedicarboxylic acid dimethyl, 2,6-naphthalenedicarboxylic acid diethyl, and 1,4-naphthalenedicarboxylic acid and ester-forming derivatives of aromatic dicarboxylic acids such as dimethyl carboxylate and diethyl 1,4-naphthalenedicarboxylic acid. Among them, 2,6-naphthalenedicarboxylic acid and an ester-forming derivative of 2,6-naphthalenedicarboxylic acid are particularly preferable from the viewpoint of refractive index and dispersibility with other resins.

Visibility is improved by using polyester in which the dicarboxylic acid component having such a naphthalene skeleton accounts for 30 mol% or more of the total dicarboxylic acid component, more preferably 35 mol% or more, and still more preferably 40 mol% or more. It is preferable because it can be done.

Moreover, as a constituent component of the polyester resin (b) containing a naphthalene skeleton, you may use together the following polyhydric carboxylic acid and polyhydric hydroxy compound which do not have a naphthalene skeleton, for example. That is, as polyhydric carboxylic acid, terephthalic acid, isophthalic acid, orthophthalic acid, phthalic acid, 4,4'- diphenylcarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 2-potassium sulfoterephthalic acid, 5-sodium sulfoyl Sophthalic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, glutaric acid, succinic acid, trimellitic acid, trimesic acid, pyromellitic acid, trimellitic anhydride, phthalic anhydride, p-hydroxybenzoic acid , trimellitic acid monopotassium salt, ester-forming derivatives thereof, etc. can be used, and examples of the polyvalent hydroxy compound include ethylene glycol, 1,2-propylene glycol, 1,3-propanediol, 1,4-butanediol, 1, 6-hexanediol, 2-methyl-1,5-pentanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, p-xylylene glycol, bisphenol A-ethylene glycol adduct, diethylene glycol, triethylene Glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polytetramethylene oxide glycol, dimethylolpropionic acid, glycerin, trimethylolpropane, sodium dimethylolethylsulfonate, potassium dimethylolpropionate, etc. are mentioned.

In addition, the polyester resin (b) in the present invention is a co-polyester resin having an aromatic dicarboxylic acid component containing a sulfonic acid metal base in an amount of 1 to 30 mol% based on the total dicarboxylic acid component of the polyester. desirable. When it is less than 1 mol%, the polyester resin may not exhibit water solubility, and compatibility with the acrylic urethane copolymer resin (a), the isocyanate compound (c), and the oxazoline compound (d) also decreases, so the resin layer The uniformity and transparency of (X) may fall. Moreover, when it exceeds 30 mol%, dispersibility with other resin falls and transparency, heat-and-moisture-resistance adhesiveness, and boiling-resistant adhesiveness become inferior easily.

Examples of the aromatic dicarboxylic acid component containing a sulfonic acid metal base include an alkali metal salt of sulfophthalic acid, an alkali metal salt of sulfoisophthalic acid, an alkali metal salt of sulfoterephthalic acid, an alkaline earth metal salt of sulfophthalic acid, and an alkaline earth salt of sulfoisophthalic acid. Metal salts, alkaline earth metal salts of sulfoterephthalic acid, alkali metal salts of sulfo-2,6-naphthalenedicarboxylic acid, alkali metal salts of sulfo-2,3-naphthalenedicarboxylic acid, sulfo-1,4-naphthalenedicarboxylic acid alkali metal salt of, alkaline earth metal salt of sulfo-2,6-naphthalenedicarboxylic acid, alkaline earth metal salt of sulfo-2,3-naphthalenedicarboxylic acid, alkaline earth salt of sulfo-1,4-naphthalenedicarboxylic acid The compound which has sulfonic acid bases, such as a metal salt, is mentioned.

Examples of the aromatic dicarboxylic acid component containing a sulfonic acid metal base other than the above include an alkali metal salt of dimethyl sulfophthalate, an alkali metal salt of dimethyl sulfoisophthalate, an alkali metal salt of dimethyl sulfoterephthalate, and an alkali of dimethyl sulfophthalate. Earth metal salts, alkaline earth metal salts of dimethyl sulfoisophthalate, alkaline earth metal salts of dimethyl sulfoterephthalate, alkali metal salts of dimethyl sulfo-2,6-naphthalenedicarboxylate, and dimethyl sulfo-2,3-naphthalenedicarboxylate Alkali metal salts, alkali metal salts of dimethyl sulfo-1,4-naphthalenedicarboxylate, alkaline earth metal salts of dimethyl sulfo-2,6-naphthalenedicarboxylic acid, alkalis of dimethyl sulfo-2,3-naphthalenedicarboxylate and salts of ester-forming derivatives of aromatic dicarboxylic acids having sulfonic acid bases such as earth metal salts and alkaline earth metal salts of dimethyl sulfo-1,4-naphthalenedicarboxylic acid.

Among these, alkali metal salts of sulfoisophthalic acid, alkaline earth metal salts of sulfoisophthalic acid, alkali metal salts of ester-forming derivatives of sulfoisophthalic acid, and alkaline earth metal salts are particularly preferable.

Specific examples of the alkali metal salt of dimethyl sulfophthalate include dimethyl lithium 5-sulfophthalate, sodium dimethyl 5-sulfophthalate, dimethyl potassium 5-sulfophthalate, and dimethyl cesium 5-sulfophthalate, and the alkali metal salt of dimethyl sulfophthalate described above. Specific examples of the earth metal salt include bis(5-dimethyldimethylsulfophthalate)magnesium, bis(5-sulfophthalatedimethyl)calcium, and bis(5-sulfophthalatedimethyl)barium. Although specific examples are abbreviate|omitted, the same applies to the alkali metal salts and alkaline-earth metal salts of dimethyl sulfoisophthalate and dimethyl sulfoterephthalate.

In addition, when the polyester resin (b) in the present invention contains a diol component represented by the following formula (1) as a diol component of the polyester resin, dispersibility with other resins is improved, and visibility is improved. It is preferable because Since following formula (1) has bisphenol S skeleton which has S element with high refractive index, the refractive index of a polyester resin (b) can be raised. On the other hand, even when a bisphenol compound including bisphenol A having a structure similar to that of Formula (1) is used as a diol component, the dispersibility improvement effect and visibility improvement effect with other resins compared to when the diol component represented by Formula (1) is used falls

Here, X ¹ , X ² : -(C _n H _2n O) _m -H n=2 or more and 4 or less, m=1 or more and 15 or less integers are represented. Here, ^{the oxyalkylene unit constituting X 1} and X ² has 2 or more and 4 or less carbon atoms, which includes an oxyethylene unit, an oxypropylene unit, an oxybutylene unit and/or an oxytetramethylene unit, but oxyethylene units and/or oxypropylene units (n=2 or 3). Moreover, as for the repetition number (m) of an oxyalkylene group, it is preferable to set it as 1 or more and 15 or less, It is more preferable to set it as 1 or more and 4 or less, It is still more preferable to set it as 1 or 2.

It is preferable that the polyester resin (b) in this invention is a co-polyester resin which contains 5 mol% or more and 50 mol% or less of the diol component represented by Formula (1) with respect to all the diol components of polyester. More preferably, it is a copolyester resin containing 10 mol% or more and 40 mol% or less.

Moreover, it is preferable that the polyester resin (b) contains at least 1 sort(s) of the diol compound represented by following formula (3) as a diol component other than said Formula (1).

(However, X ³ : -(C _x H _2x O) _y -, x= represents an integer of 2 or more and 10 or less, y=1 or more and 4 or less)

Examples of the alkanediol having 2 or more and 10 or less carbon atoms (x=2 or more and 10 or less) include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, 1,8 -octanediol, 1,10-decanediol, etc. are mentioned, Among them, 1, 3- propanediol and 1, 4- butanediol (x=2 or 3) are preferable. Moreover, it is preferable that they are 1 or more and 4 or less, and, as for y which is the repeating number of an oxyalkylene group, 1 or more and 3 or less are more preferable. It is preferable that the polyester resin (b) in this invention is a co-polyester resin which contains 5 mol% or more and 50 mol% or less of the diol component represented by Formula (3) with respect to all the diol components of polyester. More preferably, it is a copolyester resin containing 10 mol% or more and 40 mol% or less. By having such an oxyalkylene group, the hydrophilicity of a polyester resin (b) improves, and since dispersibility with other resin can be improved, it is more preferable.

Moreover, the intrinsic viscosity of the polyester resin (b) used for this invention is although it does not specifically limit, From an adhesive point, it is preferable that it is 0.3 dl/g or more and 2.0 dl/g or less, It is a thing of 0.4 dl/g or more and 1.0 dl/g or less more preferably. The intrinsic viscosity in the present invention is a value measured at 35°C by dissolving 0.3 g of a polyester resin in 25 ml of a mixed solvent of phenol/tetrachloroethane = 40/60 (weight ratio) and using a Canon Finsk type viscometer.

In addition, the polyester resin (b) according to the present invention has a refractive index of 1.58 or more, preferably 1.61 or more and 1.65 or less. In the present invention, the refractive index is a value measured at 25°C using an Abbe refractometer by molding a polyester resin into a resin plate having a thickness of 0.5 mm using a mini hot press. For the measurement, monobromonaphthalene is used as an intermediate solution.

The laminated polyester film of this invention WHEREIN: The said polyester resin (b) can be manufactured with the following manufacturing methods. For example, dimethyl naphthalene dicarboxylate as a dicarboxylic acid component having a naphthalene skeleton, and sodium 5-sulfoisophthalate dimethyl sodium as an aromatic dicarboxylic acid component containing a sulfonic acid metal base, and Formula (1) A compound obtained by adding 2 moles of ethylene oxide to 1 mole of bisphenol S as a diol component to be used, and ethylene glycol as a diol component represented by Formula (3) are subjected to a transesterification reaction in the presence of a known polymerization catalyst, followed by a high temperature and high vacuum A method for producing by a transesterification-polycondensation reaction in which a low molecular weight compound is subjected to a polycondensation reaction while distilling off, dimethyl naphthalenedicarboxylic acid as a dicarboxylic acid component having a naphthalene skeleton, and aromatic dicarboxyl containing a sulfonic acid metal base Dimethyl sodium 5-sulfoisophthalate as an acid component, a compound obtained by adding 2 moles of ethylene oxide to 1 mole of bisphenol S as a diol component represented by Formula (1), and a diol component represented by Formula (3) After transesterification reaction of ethylene glycol in the presence of a known polymerization catalyst, polycondensation reaction and depolymerization reaction while distilling off low molecular weight compounds under high temperature and high vacuum A method for preparing by transesterification-polycondensation-depolymerization reaction, naphthalene skeleton Dimethyl naphthalene dicarboxylate as a dicarboxylic acid component having, sodium 5-sulfoisophthalate dimethyl sodium as an aromatic dicarboxylic acid component containing a sulfonic acid metal base, and bisphenol S as a diol component represented by Formula (1) A compound obtained by adding 2 moles of ethylene oxide to 1 mole and ethylene glycol as a diol component represented by the formula (3) are subjected to a polycondensation reaction while distilling off the low molecular weight compound in the presence of a known polymerization catalyst at high temperature and high vacuum. The manufacturing method etc. are mentioned.

At this time, an alkali metal, alkaline earth metal, manganese, cobalt, zinc, antimony, germanium, titanium compound, etc. can be used as a reaction catalyst.

It is preferable that Tg of a polyester resin (b) is 0 degreeC or more and 130 degrees C or less, More preferably, it is 10-85 degreeC. If the Tg is less than 0°C, for example, the moisture and heat resistance and boiling resistance are poor, or a blocking phenomenon occurs in which the resin layers (X) adhere to each other, and conversely, when it exceeds 130°C, the stability or water dispersibility of the resin This is not preferable because it may fall.

(3) isocyanate compound (c)

The isocyanate compound (c) in this invention means the compound containing the structure derived from the isocyanate compound (c) demonstrated below or the isocyanate compound (c) demonstrated below.

As the isocyanate compound (c), for example, tolylene diisocyanate, diphenylmethane-4,4'-diisocyanate, methaxylylene diisocyanate, hexamethylene-1,6-diisocyanate, 1,6-diisocyanate hexane, tolyl Rendiisocyanate and hexanetriol adduct, tolylene diisocyanate and trimethylolpropane adduct, polyol-modified diphenylmethane-4,4'-diisocyanate, carbodiimide-modified diphenylmethane-4,4'-diisocyanate, Isophorone diisocyanate, 1,5-naphthalene diisocyanate, 3,3'-bitolylene-4,4' diisocyanate, 3,3' dimethyldiphenylmethane-4,4'-diisocyanate, metaphenylene diisocyanate, etc. is available. In particular, when a polymeric isocyanate compound having a plurality of isocyanate groups is used in the terminal or side chain of a polymer such as a polyester resin or an acrylic resin, since the toughness of the layer (X) is increased, it can be preferably used.

When applying to the in-line coating method mentioned later as a method of forming the resin layer (X), it is preferable that an isocyanate compound (c) is an aqueous dispersion. In particular, from the viewpoint of the pot life of the coating composition, a blocked isocyanate-based compound in which an isocyanate group is masked with a blocking agent or the like is particularly preferable. As a crosslinking reaction of a blocking agent, the said blocking agent volatilizes with the heat|fever of the drying process after application|coating, an isocyanate group is exposed, and the system which raise|generates a crosslinking reaction is known. In addition, the isocyanate group may be a monofunctional type or a polyfunctional type, but the crosslinking density of the layer (X) is improved in the case of a polyfunctional block polyisocyanate-based compound. It is preferable because it is excellent in property.

Examples of the low-molecular or high-molecular compound having two or more block isocyanate groups include tolylene diisocyanate, hexamethylene diisocyanate, trimethylolpropane tri-mol adduct, polyvinyl isocyanate, vinyl isocyanate copolymer, and polyurethane-terminated diisocyanate. , methyl ethyl ketone oxime block body of tolylene diisocyanate, sodium hyposulfite block body of hexamethylene diisocyanate, methyl ethyl ketone oxime block body of polyurethane terminal diisocyanate, phenol to tolylene diisocyanate 3 mole adduct of trimethylol propane A block body, etc. can be used.

When the total of the acrylic/urethane copolymer resin (a) and the polyester resin (b) in the coating composition is 100 parts by weight, it is preferable to contain 3 parts by weight or more and 20 parts by weight or less of the isocyanate compound (c), more preferably is 4 parts by weight or more and 18 parts by weight or less, more preferably 5 parts by weight or more and 16 parts by weight or less.

By making content of the isocyanate compound (c) into the said range and making the sum total of content of an oxazoline compound (d) into a predetermined range, the resin layer (X) has high transparency, moist-heat adhesiveness, boiling-resistant adhesiveness, excellent visibility can be demonstrated. When content of the isocyanate compound (c) in a coating composition is less than 3 weight part, adhesiveness with a hard-coat layer is inferior. Moreover, when it exceeds 20 weight part, transparency of a laminated polyester film deteriorated, and the refractive index of a resin layer falls, and visibility at the time of laminating|stacking a hard-coat layer is inferior.

(4) oxazoline compounds (d)

The oxazoline compound (d) in the present invention is not particularly limited as long as it has at least one oxazoline group or oxazine group per molecule. A polymer type polymerized together is preferable. By using a high molecular weight oxazoline compound, the layer (X) of the present invention is formed on a thermoplastic resin film, and the flexibility, toughness, water resistance, and solvent resistance of the layer (X) are improved when a laminated polyester film is used. because it becomes

Examples of the addition polymerizable oxazoline group-containing monomer include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl- 2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, and 2-isopropenyl-5-ethyl-2-oxazoline are mentioned. These may be used by 1 type and may use 2 or more types of mixtures. Among these, 2-isopropenyl-2-oxazoline is suitable also because it is easy to obtain industrially. The other monomer is not limited as long as it is a monomer copolymerizable with the addition polymerizable oxazoline group-containing monomer, for example, alkyl acrylate, alkyl methacrylate (as the alkyl group, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group , isobutyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group) such as (meth)acrylic acid esters, acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, styrenesulfonic acid, and its unsaturated carboxylic acids such as salts (sodium salt, potassium salt, ammonium salt, tertiary amine salt, etc.); unsaturated nitriles such as acrylonitrile and methacrylonitrile; Acrylamide, methacrylamide, N-alkyl acrylamide, N-alkyl methacrylamide, N,N-dialkyl acrylamide, N,N-dialkyl methacrylate (as alkyl group, methyl group, ethyl group, n-propyl group, unsaturated amides such as isopropyl group, n-butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group, etc.), vinyl acetate, vinyl propionate, acrylic acid, and methacrylic acid Vinyl esters such as those added with polyalkylene oxide, vinyl ethers such as methyl vinyl ether and ethyl vinyl ether, α-olefins such as ethylene and propylene, halogens such as vinyl chloride, vinylidene chloride, and vinyl fluoride containing α,β-unsaturated monomers, α,β-unsaturated aromatic monomers such as styrene and α-methylstyrene, and the like, and one or two or more types of these monomers can be used.

The content of the oxazoline compound (d) is preferably 20 to 50 parts by weight when the content of (a) and (b) in the coating composition is 100 parts by weight. If it is in the range of 20 to 50 parts by weight, the resin layer (X) of the present invention is formed on a polyester film, and when a laminated polyester film is formed, high moisture and heat resistance, UV adhesion, boiling resistance, and further oligomer suppression properties can be imparted to the laminated polyester film.

(5) melamine compound (e)

The resin layer (X) of this invention may be a layer formed using the coating composition containing the melamine compound (e) further.

Although it does not specifically limit as a melamine compound (e), From the point of hydrophilization, the methylol melamine derivative obtained by condensing melamine and formaldehyde is etherified by dehydration condensation reaction of methyl alcohol, ethyl alcohol, isopropyl alcohol, etc. as a lower alcohol. one compound and the like.

Examples of the methylolation melamine derivative include monomethylolmelamine, dimethylolmelamine, trimethylolmelamine, tetramethylolmelamine, pentamethylolmelamine and hexamethylolmelamine.

If the resin layer (X) of the present invention is a layer formed by using the coating composition containing the melamine compound (e), it is preferable because the adhesiveness can be improved. Process contamination due to volatilization of the melamine compound is a problem, or the melamine compound generates formaldehyde harmful to the human body through a crosslinking reaction. Therefore, when content of a melamine compound (e) makes content of (a) and (b) in a coating composition 100 weight part, it is preferable that it is 30 weight part or less. More preferably, they are 5 weight part or more and 30 weight part or less, Especially preferably, they are 10 weight part or more and 25 weight part or less.

When 5 parts by weight or more and 30 parts by weight or less of the melamine compound (e) is used, the layer (X) of the present invention is formed on a polyester film, and the adhesiveness of the laminated polyester film and the hard coat layer when the laminated polyester film is used can be made better.

(6) Formation method of resin layer (X)

The resin layer (X) in the present invention is the above-mentioned acrylic/urethane copolymer resin (a), polyester resin (b), isocyanate compound (c), and oxazoline compound on at least one side of the polyester film serving as the above-mentioned base material. It is a layer formed using the coating composition containing (d). Here, "formed using" means an acrylic urethane copolymer resin (a), a polyester resin (b), an isocyanate compound (c), an oxazoline compound (d), and, if necessary, on at least one side of the polyester film serving as the substrate. Accordingly, the coating composition including the mixture containing the melamine compound (e) is formed in a layer shape on the base film, and curing or crosslinking treatment is performed as necessary. To give specific examples, the acrylic/urethane copolymer resin (a), polyester resin (b), isocyanate compound (c), oxazoline compound (d), and, if necessary, a melamine compound (e), and, if necessary, a solvent A resin layer (X) can be formed on the polyester film by applying a coating solution containing a surfactant or the like on the polyester film, drying the solvent as necessary, and curing or crosslinking if necessary.

Moreover, in this invention, it is preferable to use the aqueous solvent (f) as a solvent. It is because not only can suppress rapid evaporation of the solvent in a drying process by using an aqueous solvent, and can form uniform resin layer (X), but it is excellent in the point of environmental load.

Here, the aqueous solvent (f) refers to water or water and alcohols such as methanol, ethanol, isopropyl alcohol and butanol, ketones such as acetone and methyl ethyl ketone, glycols such as ethylene glycol, diethylene glycol, propylene glycol, etc. It indicates that an organic solvent soluble in water is mixed in an arbitrary ratio. By using an aqueous solvent, rapid evaporation of the solvent in a drying process can be suppressed, and a uniform resin layer can be formed. Moreover, it is excellent also in the point of environmental load.

Although either an in-line coating method and an off-coating method can be used for the coating method of the said coating composition on the polyester film, Preferably it is an in-line coating method.

An in-line coating method is a method of apply|coating within the manufacturing process of a polyester film. Specifically, it refers to a method in which a polyester resin is melt-extruded, then applied in an arbitrary step, after biaxial stretching, heat treatment, and winding up, usually in a substantially amorphous state obtained by melt-extrusion and rapid cooling ( unoriented) polyester film (hereinafter referred to as "A film"), then uniaxially stretched (uniaxially oriented) polyester film (hereinafter referred to as "B film") stretched in the longitudinal direction, or further stretched in the width direction It is apply|coated to the film in any one of the biaxially stretched (biaxial orientation) polyester films (henceforth "C film") before the performed heat treatment.

In the present invention, the coating composition is applied to the polyester film of any one of the A film, B film, or C film before crystal orientation is completed, and then the polyester film is stretched uniaxially or biaxially, and a solvent It is preferable to adopt a method of forming the resin layer (X) while performing heat treatment at a temperature higher than the boiling point of the polyester film to complete the crystal orientation of the polyester film. According to this method, since film forming of a polyester film and coating-drying of a coating composition (namely, formation of resin layer (X)) can be performed simultaneously, there exists an advantage in manufacturing cost. Moreover, in order to extend|stretch after application|coating, it is easy to make the thickness of resin layer (X) thinner. The thickness of the resin layer (X) is preferably a thickness that can cancel optical interference from the viewpoint of visibility, and is 50 nm or more and 200 nm or less, more preferably 60 nm or more and 150 nm or less, and still more preferably 70 nm or more and 130 nm or less.

Especially, the method of apply|coating the coating composition to the film (B film) uniaxially stretched in the longitudinal direction, then extending|stretching in the width direction, and heat-processing was excellent. After coating on an unstretched film, since the stretching step is less than the method of biaxial stretching, it is difficult to generate defects or cracks in the resin layer (X) due to stretching, and the resin layer (X) excellent in transparency and smoothness because it can be formed.

On the other hand, the offline coating method is a process separate from the film forming process on the film or A film after the A film is stretched uniaxially or biaxially, and heat treatment is performed to complete the crystal orientation of the polyester film. method of dispensing.

In the present invention, the resin layer (X) is preferably formed by an in-line coating method from the various advantages described above.

Therefore, in the present invention, a preferred method of forming the resin layer (X) is a method of forming a water-based coating composition using an aqueous solvent (f) on a polyester film using an in-line coating method, followed by drying. Moreover, more preferably, it is a method of in-line-coating the coating composition on the B film after uniaxial stretching. Moreover, it is preferable that the solid content concentration of the coating composition in a coating liquid is 5 weight% or less. When solid content concentration is 5 % or less, favorable applicability|paintability can be provided to a coating composition, and the laminated polyester film which has a transparent and uniform resin layer can be manufactured.

(7) Method for producing a coating solution comprising a coating composition using an aqueous solvent (f)

The coating composition using the water-based solvent (f) is a water-based compound of the acrylic/urethane copolymer resin (a), the polyester resin (b), the isocyanate compound (c), and the oxazoline compound (d), which are optionally water-oxidized or water-soluble. and mixing and stirring the aqueous solvent (f) at a desired solid content weight ratio in any order.

Then, as needed, it can produce by mixing and stirring a melamine compound (e) in the said coating composition at a desired solid content weight ratio in arbitrary order.

Mixing and stirring may be performed by shaking the container by hand, using a magnetic stirring bar or stirring blade, ultrasonic irradiation, vibration dispersion, or the like.

Moreover, you may add various additives, such as a lubricant, an inorganic particle, organic particle|grains, surfactant, and antioxidant, as needed to the extent which does not deteriorate the characteristic of the resin layer formed with the coating composition.

(8) Application method

As the coating method of the coating composition to the polyester film, any method such as a known coating method, for example, a bar coating method, a reverse coating method, a gravure coating method, a die coating method, and a blade coating method can be used.

(9) Laminated polyester film manufacturing method

Next, with respect to the manufacturing method of the laminated polyester film of this invention, although the case where a polyethylene terephthalate (hereinafter, abbreviated as PET) film is used for a polyester film is used as an example as an example, it is not necessarily limited to this. First, the PET pellets are sufficiently vacuum-dried, then supplied to an extruder, melt-extruded into a sheet at about 280° C., and solidified by cooling to prepare an unstretched (non-oriented) PET film (A film). This film is stretched 2.5 to 5.0 times in the longitudinal direction with a roll heated at 80 to 120° C. to obtain a uniaxially oriented PET film (B film). The coating composition of the present invention prepared at a predetermined concentration is applied to one side of the B film. At this time, you may surface-treat corona discharge treatment etc. to the coated surface of PET film before application|coating. By performing surface treatment such as corona discharge treatment, the wettability of the coating composition to the PET film can be improved, repelling of the coating composition can be prevented, and a uniform coating thickness can be achieved.

After application, the end of the PET film is gripped with a clip, guided to a heat treatment zone (preheating zone) at 80 to 130° C., and the solvent of the coating composition is dried. After drying, it is stretched 1.1 to 5.0 times in the width direction. Then, it guide|induced to 160-240 degreeC heat processing zone (heat setting zone), heat processing for 1 to 30 second is performed, and crystal orientation is completed.

In this heat treatment step (heat setting step), if necessary, 3 to 15% relaxation treatment may be performed in the width direction or the length direction. The laminated polyester film obtained in this way turns into a laminated polyester film excellent in transparency and the adhesiveness with a hard-coat layer, heat-and-moisture adhesiveness, boiling-resistant adhesiveness, and visibility at the time of laminating|stacking a hard-coat layer.

[Methods for measuring characteristics and methods for evaluating effects]

(1) Transparency evaluation method

Transparency was evaluated by initial haze (%). The measurement of haze was performed using Nippon Denshoku Kogyo Co., Ltd. turbidimeter "NDH5000", after leaving a laminated polyester film to stand for 1 hour in a state (temperature 23 degreeC, relative humidity 65%). The average value measured three times was made into the initial stage haze of the laminated polyester film. Transparency was evaluated in four steps according to the value of the haze. C is a practically problematic level, B is a practical use level, S and A were made favorable.

S: less than 1.0%

A: 1.0% or more and less than 2.0%

B: 2.0% or more and less than 3.0%

C: 3.0% or more.

(2) Evaluation method of adhesiveness with hard-coat layer

(2-1) Evaluation method of initial adhesiveness

On the surface of the resin layer (X) of the laminated polyester film, a UV cured resin mixed in the following ratio was uniformly applied using a bar coater so that the cured UV cured resin layer had a film thickness of 2 µm.

Dipentaerythritol hexaacrylate: 60 parts by weight

(“Kayarad” (registered trademark) DPHA manufactured by Nippon Kayaku Co., Ltd.)

・Pentaerythritol triacrylate: 40 parts by weight

(“Kayarad” (registered trademark) PETA manufactured by Nippon Kayaku Co., Ltd.)

・Photoinitiator (“Irgacure” (registered trademark) 184 manufactured by Nagase Sangyo Co., Ltd.): 3 parts by weight

·Methyl ethyl ketone: 100 parts by weight

Then, a condensing high-pressure mercury lamp (H03-L31 manufactured by Eye Graphics Co., Ltd.) having an irradiation intensity of 120 W/cm set at a height of 9 cm from the surface of the UV-curing resin layer so that the accumulated irradiation intensity is 300 mJ/cm ² An ultraviolet-ray was irradiated, it hardened, and the hard-coat laminated polyester film in which the hard-coat layer was laminated|stacked on the laminated polyester film was obtained. ^{100 crosscuts of 1 mm 2} were put on the hard coat laminated surface of the obtained hard coat laminated polyester film, a cellophane tape (registered trademark) (Nichiban Co., Ltd. CT405AP) was attached, and 1.5 kg/cm ^{2 with a hand roller} After pressurizing with a load of , it peeled rapidly in a 90 degree direction with respect to the hard-coat laminated polyester film. Adhesiveness was evaluated in four stages according to the number of remaining crosscuts. The number of the remaining crosscuts was taken as the average value performed three times. C is a practically problematic level, B is a practical use level, S and A were made favorable.

S: 100 remaining

A: 80 to 99 remaining

B: 50 to 79 remaining

C: 0 to less than 50 remaining.

(2-2) Evaluation method of heat-and-moisture adhesiveness

The hard-coat laminated polyester film was obtained by the method similar to (2-1). The obtained hard coat laminated polyester film was left to stand for 240 hours in a constant temperature and humidity chamber with a temperature of 85 ° C. and a relative humidity of 85%, and then dried in a state (23 ° C., 65% relative humidity) for 1 hour, and hard coat lamination for wet heat adhesion test A sample was obtained. Adhesive evaluation was performed by the method similar to (2-1) about the obtained hard-coat lamination|stacking sample for wet-and-heat adhesion tests, and four-step evaluation was performed. The number of the remaining crosscuts was taken as the average value performed three times. C is a practically problematic level, B is a practical use level, S and A were made favorable.

(2-3) Evaluation method of boiling-resistant adhesiveness

The said UV curable resin was apply|coated and hardened on the resin layer surface of a laminated polyester film similarly to evaluation of (2-1), and the boiling-resistant adhesiveness evaluation sample was obtained. Next, a boiling water adhesion evaluation sample is cut into a size of 10 cm × 10 cm, fixed to a clip and suspended in a state, and then the entire surface of the laminated polyester film is placed in boiling water (100° C.) containing pure water prepared in a beaker. It was put in this immersion state for 18 hours. Then, the boiling-proof adhesiveness evaluation sample was dried in the taken-out state (23 degreeC, 65% of relative humidity) for 1 hour, and the hard-coat lamination|stacking sample for boiling-resistant adhesiveness tests was obtained. Adhesive evaluation was performed by the method similar to (2-1) about the obtained hard-coat lamination|stacking sample for boiling-resistant adhesiveness tests, and four-step evaluation was performed. The number of the remaining crosscuts was taken as the average value performed three times. C is a level with a problem practically, B is a practical use level, and it was set as the thing of S and A good.

(2-4) Evaluation method of UV adhesion resistance

UV cured resin was applied to the surface of the resin layer (X) of the laminated polyester film in the same manner as in the evaluation of (2-1) and cured to obtain a sample for a UV adhesive resistance test. Then, ultraviolet-ray was irradiated so that integrated irradiation intensity might be set to 500 mJ/cm<^2> similarly to (2-1), and it repeated 3 times in total until the total accumulated irradiation intensity became 1500 mJ/cm<^2>. Adhesive evaluation was performed by the method similar to (2-1) about the obtained hard-coat lamination|stacking sample for UV adhesive resistance tests, and four-step evaluation was performed. C is a practically problematic level, B is a practical use level, S and A were made favorable.

(3) Evaluation method of transparency of hot water

The hot water transparency was evaluated by the haze change amount (ΔHz) (%) before and after immersion of the laminated polyester film in hot water. After cutting the laminated polyester film to a size of 10cm × 10cm, fixing it to a clip to make it suspended, and then immersing the entire surface of the laminated polyester film in a boiling water (100°C) containing pure water prepared in a beaker. put in for 1 hour. Then, the laminated polyester film was taken out, it dried in the state (23 degreeC, 65% of relative humidity) for 1 hour, and the sample for the hot water transparency test was obtained. Here, in the case of a sample having a resin layer (X) on only one side of the polyester film, a nonwoven fabric containing acetone on the side of the polyester film opposite to the resin layer (manufactured by Ozu Sangyo Co., Ltd., Hyze Gauze NT-4) ), and left to dry for 1 hour under normal conditions to remove the oligomers deposited on the polyester film side opposite to the resin layer, thereby preparing a sample for a hot water transparency test.

Transparency evaluation was performed by the method similar to (1) about the obtained sample for hot water transparency test, and the obtained value was made into haze (%) after boiling test process. From this value, the value obtained by subtracting the haze (%) (initial haze) before boiling test treatment was defined as the amount of change in film haze before and after boiling test treatment ΔHz (ΔHz = haze after boiling test treatment - haze before boiling test treatment), and evaluation of hot water transparency was performed, and a four-step evaluation was performed. C is a practically problematic level, B is a practical use level, S and A were made favorable.

S: less than 3.0%

A: 3.0% or more and less than 5.0%

B: 5.0% or more and less than 6.0%

C: 6.0% or more.

(4) Evaluation method of visibility (interference fringes)

The hard-coat film by which the hard-coat layer of thickness 2 micrometers was laminated|stacked on the laminated polyester film was obtained by the method similar to (2-1). Then, a sample of the size of 8 cm (hard coat film width direction) x 10 cm (hard coat film length direction) is cut out from the obtained hard coat film, and a black glossy tape (Yamato Co., Ltd. vinyl tape) on the opposite surface of the hard coat layer No.200-50-21: black) was pasted so as not to contain air bubbles.

This sample was placed in a dark room at 30 cm directly under a 3-wavelength fluorescent lamp (Matsushita Denki Sangyo Co., Ltd. 3-wavelength main white (F·L 15EX-N 15W)), and the degree of interference non-uniformity was observed with the naked eye while changing the viewing angle. , the following evaluations were performed. A thing or more was made favorable.

S: Almost no interference non-uniformity

A: Slight interference unevenness is seen

B: Weak interference non-uniformity is seen

C: The interference nonuniformity is strong.

(5) Evaluation method of the film thickness of the resin layer (X)

For the laminated polyester film, a _{sample was prepared by the RuO 4} dyeing ultra-thin film sectioning method. By observing the cross section of the obtained sample using a transmission electron microscope (TEM), the thickness of the resin layer (X) on the laminated polyester film was measured. As for the thickness of the resin layer (X), the thickness of the resin layer was read from the image image|photographed by 200,000 times magnification by TEM. The resin layer thickness of 20 points|pieces was measured, and the average value was made into the film thickness (nm) of the resin layer (X).

- Measurement apparatus: Transmission electron microscope (Hitachi Co., Ltd. product H-7100FA type).

(6) Evaluation method of spectral reflectance

The film sheet cut to the A4 cut size was divided into 3 vertical and horizontal sections, respectively, and a total of 9 points was used as a measurement sample. The long side was made into the longitudinal direction. For measurement of the spectral reflectance, a 50 mm wide black glossy tape (Vinyl Tape No. 200-50-21: Black) manufactured by Yamato Co., Ltd. was placed on the back side of the measurement surface (the resin layer (X)) with the sample so as not to contain air bubbles. After aligning the longitudinal direction of the tape and bonding, it cut out into a sample piece of 4 cm square, and the spectral reflectance at 5 degrees of incidence angle was measured with the spectrophotometer (Shimadzu Corporation UV2450). The direction of setting the sample to the measuring device was aligned with the longitudinal direction of the sample in the front-back direction toward the front of the measuring device. Also used a part of the Al ₂ O ₃ plate as standard reflection plate to screen based on the reflectance. The spectral reflectance of the surface side having the resin layer (X) is measured in a wavelength range of 450 nm or more and 650 nm or less, and the minimum value (%) of the spectral reflectance in the wavelength range of 450 nm or more and 650 nm or less on the resin layer (X) side is obtained. did. The measurement was performed with respect to 9 sample pieces cut out at a 4 cm square, and calculated|required from the average value of 9 points|pieces.

(7) Evaluation method of dispersion index (determination by cross-sectional photograph of transmission electron microscope (TEM))

A sample of the surface of the resin layer (X) is prepared by _{the RuO 4} dyeing ultra-thin film sectioning method for the laminated polyester film. A cross-sectional photograph of the obtained sample was obtained using a transmission electron microscope (TEM) under the following conditions. In the obtained cross-sectional photograph, the number of aggregates containing the acrylic urethane copolymer resin (a) having a size observed in the viewing area (Z direction × X direction: 500 nm × 1200 nm) of 40 nm or more is observed, and the number of the obtained aggregates is shown below. It is converted into the number per predetermined area (120000 nm ^{2 ) by the formula.}

(the number of aggregates having an observed size of 40 nm or more) × 120000/area occupied by the resin layer (X) in the viewing area

The observation was performed with respect to 10 visual fields, and the number to the first decimal place of the average number of aggregates observed per predetermined area was rounded off, and it was set as the dispersion index. The variance index represents an integer greater than or equal to 0. The dispersion index in the present invention made the thing of 5 or less favorable.

・Measuring device: Transmission electron microscope (Hitachi Co., Ltd. H-7100FA type)

Measurement conditions: Acceleration voltage (100 kV)

· Magnification: 20,000 times.

(8) Evaluation method of change amount ΔR of spectral reflectance before and after boiling treatment test

The spectral reflectance (%) before the boiling treatment test is the same as the method described in the evaluation method of (6) spectral reflectance, and the spectral reflectance is measured for a wavelength range of 400 nm or more and 800 nm or less on the side of the resin layer (X), and as the average value saved

In addition, the spectral reflectance (%) after a boiling process test was calculated|required with the following method. That is, 9 samples of the laminated polyester film were cut out to a size of 10 cm × 10 cm, fixed to a clip to be suspended, and then the entire surface of the laminated polyester film was placed in boiling water (100° C.) containing pure water prepared in a beaker. It boiled for 5 hours in the state immersed (boiling treatment test). Then, the laminated polyester film was taken out, it dried in a normal state (23 degreeC, 65% of relative humidity) for 1 hour, and the sample for spectral reflectance measurement after a boiling process test was obtained.

With respect to the obtained sample for spectral reflectance measurement after the boiling treatment test, a 50 mm wide black glossy tape (Yamato Co., Ltd. vinyl tape No. 200-50-21: black) on the back side of the measurement surface (the resin layer (X)) was applied. After bonding so as not to contain air bubbles, it was cut into a 4 cm square sample piece, and spectral reflectance was measured with a spectrophotometer (UV2450 manufactured by Shimadzu Corporation) for a wavelength range of 400 nm or more and 800 nm or less at an incident angle of 5°. . The average value of the wavelength range of 400 nm or more and 800 nm or less of wavelength was made into the spectral reflectance (%) after a boiling process test, and it calculated|required as the average value of 9 sample pieces cut out at a 4 cm square.

The absolute value of the value obtained by subtracting the average spectral reflectance average value (%) after the boiling test process from the average spectral reflectance (%) before the boiling process test obtained by the above, the change amount ΔR of the spectral reflectance before and after the boiling test process ΔR (ΔR = | Spectral reflectance - It was set as the spectral reflectance|) (%) after a mercy test process. Change amount (DELTA)R of the spectral reflectance before and behind a boiling process test made 0% or more and 2% or less favorable.

(9) Heat treatment evaluation (ΔHz after heating)

The laminated film sample was fixed to a metal frame at four sides, and the sample fixed to the metal frame in a hot air oven "HIGH-TEMP-OVEN PHH-200" manufactured by SPEC Co., Ltd. set at 150 ° C (air volume gauge "7"). It was put upright with respect to the floor in a hot air oven, and was heated for 1 hour, and then left to stand at room temperature for 1 hour. Here, the laminated film sample in which the resin layer is formed on only one side of the polyester film is a nonwoven fabric (manufactured by Ozu Sangyo Co., Ltd., Hyze gauze NT-4) containing acetone on the side of the polyester film on the opposite side to the resin layer. It was wiped off, washed with acetone and left to dry for 40 hours under normal conditions, and the oligomer deposited on the polyester film side opposite to the resin layer was removed. Thereafter, the sample was measured for haze value after heating by the initial haze evaluation method described in the preceding paragraph (1), and the difference between the haze values on one side of the resin layer before and after the heat treatment was evaluated as the ΔHz value after heating. In addition, for the laminated film sample in which the resin layer was formed on both sides of the polyester film, after heating in a hot air oven, the sample was left to stand in a normal state for 40 hours, and then the haze value after heating was measured by the initial haze evaluation method described in the preceding paragraph (1). and the difference between the haze values before and after heat treatment was set to half (50%) as the difference between the haze values of one side of the resin layer, and this was evaluated as a ΔHz value after heating. The measurement made the average value measured a total of 10 times the haze value of the sample.

<ΔHz value after heating>

S: less than 2.0%

A: More than 2.0% and less than 2.5%

B: 2.5% or more and less than 3.0%

C: 3.0% or more

In addition, heat treatment evaluation made A or more favorable.

(10) Measurement of surface zeta potential of resin layer (X)

First, the laminated polyester film is sampled at 3 cm × 1 cm according to the size of the cell for measuring the solid surface zeta potential, and a zeta electrometer (manufactured by Otsuka Denshi Co., Ltd.) so that the measurement surface is the resin layer (X) side of the laminated polyester film , ELSZ-1000, using a Flat Surface Cell), and measured three times with water (temperature: 25°C, refractive index: 1.3328, viscosity: 0.8878 (cP), dielectric constant: 78.3) as a solvent, and by Smoluchowski's formula The average value of three times of the calculated value was made into the value of the zeta potential.

Example

The present invention will be described in more detail based on Examples. However, the present invention is not limited to the following examples.

In addition, the synthesis method of the polyester resin which has an acrylic urethane copolymer resin and a naphthalene skeleton is shown in a reference example.

(Reference Example 1)

Preparation of water dispersion of acrylic urethane copolymer resin (a-1)

66 parts by weight of polyester-based urethane resin ("Hydraan" (registered trademark) AP-40(F) manufactured by DIC Co., Ltd.) in container 1 under nitrogen gas atmosphere and room temperature (25° C.), methyl methacrylate 35 weight part, 29 weight part of ethyl acrylates, and 2 weight part of N-methylolacrylamide were thrown in, and the solution 1 was obtained. Subsequently, 7 parts by weight of an emulsifier (“Rear Soap” ER-30 manufactured by ADEKA Corporation) was added, and water was added so that the solid content of the solution was 50% by weight to obtain a solution 2. 30 parts by weight of water was added to container 2 at room temperature (25°C), and the temperature was raised to 60°C. Then, the solution 2 was continuously dripped at the container 2 over 3 hours, stirring. At the same time, 3 parts by weight of a 5% by weight aqueous solution of potassium persulfate was continuously added dropwise to the container 2. After completion|finish of dripping, after further stirring for 2 hours, it cooled to 25 degreeC, reaction was complete|finished, and the acrylic urethane copolymer resin (a-1) aqueous dispersion was obtained. In addition, the solid content concentration of the obtained acrylic urethane copolymer resin (a-1) aqueous dispersion is 30 weight%.

In the following Reference Examples 2 to 13, the composition ratio of the dicarboxylic acid component and the diol component represents a value when the total dicarboxylic acid component and the total diol component are 100 mol%. In Reference Examples 2 to 13, the molar ratio of all dicarboxylic acid components to all diol components was 1:1.

(Reference Example 2)

Preparation of water dispersion of polyester resin (b-1) having a naphthalene skeleton

Water dispersion of polyester resin comprising the following copolymer composition

<Copolymerization component>

(dicarboxylic acid component)

Dimethyl 2,6-naphthalenedicarboxylic acid: 88 mol%

Dimethyl sodium 5-sulfoisophthalate: 12 mol%

(diol component)

A compound obtained by adding 2 moles of ethylene oxide to 1 mole of bisphenol S: 86 mole%

1,3-propanediol: 14 mol%.

(Reference example 3)

Preparation of aqueous dispersion of polyester resin (b-2) having an aromatic dicarboxylic acid component having a naphthalene skeleton and containing a sulfonic acid metal base

Water dispersion of polyester resin comprising the following copolymer composition

<Copolymerization component>

(dicarboxylic acid component)

Dimethyl 2,6-naphthalenedicarboxylic acid: 99 mol%

Dimethyl sodium 5-sulfoisophthalate: 1 mol%

(diol component)

A compound obtained by adding 2 moles of ethylene oxide to 1 mole of bisphenol S: 86 mole%

1,3-propanediol: 14 mol%.

(Reference Example 4)

Preparation of aqueous dispersion of polyester resin (b-3) having an aromatic dicarboxylic acid component having a naphthalene skeleton and containing a sulfonic acid metal base

Water dispersion of polyester resin comprising the following copolymer composition

<Copolymerization component>

(dicarboxylic acid component)

Dimethyl 2,6-naphthalenedicarboxylic acid: 85 mol%

Dimethyl sodium 5-sulfoisophthalate: 15 mol%

(diol component)

A compound obtained by adding 2 moles of ethylene oxide to 1 mole of bisphenol S: 86 mole%

1,3-propanediol: 14 mol%.

(Reference example 5)

Preparation of aqueous dispersion of polyester resin (b-4) having an aromatic dicarboxylic acid component having a naphthalene skeleton and containing a sulfonic acid metal base

Water dispersion of polyester resin comprising the following copolymer composition

<Copolymerization component>

(dicarboxylic acid component)

2,6-naphthalenedicarboxylic acid: 85 mol%

Dimethyl sodium 5-sulfoisophthalate: 15 mol%

(diol component)

A compound obtained by adding 2 moles of ethylene oxide to 1 mole of bisphenol S: 86 mole%

1,3-propanediol: 14 mol%.

(Reference example 6)

Preparation of aqueous dispersion of polyester resin (b-5) having an aromatic dicarboxylic acid component having a naphthalene skeleton and containing a sulfonic acid metal base

Water dispersion of polyester resin comprising the following copolymer composition

<Copolymerization component>

(dicarboxylic acid component)

Dimethyl 2,6-naphthalenedicarboxylic acid: 65 mol%

Dimethyl sodium 5-sulfoisophthalate: 35 mol%

(diol component)

A compound obtained by adding 2 moles of ethylene oxide to 1 mole of bisphenol S: 86 mole%

1,8-octanediol: 14 mol%.

(Reference example 7)

Preparation of aqueous dispersion of polyester resin (b-6) having a naphthalene skeleton and not having an aromatic dicarboxylic acid component containing a sulfonic acid metal base

Water dispersion of polyester resin comprising the following copolymer composition

<Copolymerization component>

(dicarboxylic acid component)

Dimethyl 2,6-naphthalenedicarboxylic acid: 88 mol%

trimellitic acid: 12 mol%

(diol component)

A compound obtained by adding 2 moles of ethylene oxide to 1 mole of bisphenol S: 86 mole%

Ethylene glycol: 14 mol%.

(Reference example 8)

Preparation of aqueous dispersion of polyester resin (b-7) having a naphthalene skeleton and having a bisphenol S skeleton

Water dispersion of polyester resin comprising the following copolymer composition

<Copolymerization component>

(dicarboxylic acid component)

Dimethyl 2,6-naphthalenedicarboxylic acid: 88 mol%

Dimethyl sodium 5-sulfoisophthalate: 12 mol%

(diol component)

A compound obtained by adding 2 moles of propylene oxide to 1 mole of bisphenol S: 86 mole%

Ethylene glycol: 14 mol%.

(Reference example 9)

Preparation of aqueous dispersion of ester resin (b-8) having a naphthalene skeleton and having a bisphenol S skeleton

Water dispersion of polyester resin comprising the following copolymer composition

<Copolymerization component>

(dicarboxylic acid component)

Dimethyl 2,6-naphthalenedicarboxylic acid: 88 mol%

Dimethyl sodium 5-sulfoisophthalate: 12 mol%

(diol component)

A compound obtained by adding 10 mol of propylene oxide to 1 mol of bisphenol S: 50 mol%

Ethylene glycol: 50 mol%.

(Reference example 10)

Preparation of water dispersion of polyester resin (b-9) having a naphthalene skeleton and having a bisphenol A skeleton

Water dispersion of polyester resin comprising the following copolymer composition

<Copolymerization component>

(dicarboxylic acid component)

Dimethyl 2,6-naphthalenedicarboxylic acid: 85 mol%

Dimethyl lithium 5-sulfoisophthalate: 15 mol%

(Diol component) A compound obtained by adding 2 mol of ethylene oxide to 1 mol of bisphenol A: 86 mol%

Ethylene glycol: 14 mol%.

(Reference Example 11)

Preparation of aqueous dispersion of polyester resin (b-10) having a naphthalene skeleton and having a bisphenol A skeleton

Water dispersion of polyester resin comprising the following copolymer composition

<Copolymerization component>

(dicarboxylic acid component)

Dimethyl 2,6-naphthalenedicarboxylic acid: 85 mol%

Dimethyl sodium 5-sulfoisophthalate: 15 mol%

(diol component)

A compound obtained by adding 10 mol of propylene oxide to 1 mol of bisphenol A: 86 mol%

Ethylene glycol: 14 mol%.

(Reference example 12)

Preparation of water dispersion of polyester resin (b-11) having no naphthalene skeleton

Water dispersion of polyester resin comprising the following copolymer composition

<Copolymerization component>

(dicarboxylic acid component)

Isophthalic acid: 88 mol%

Dimethyl sodium 5-sulfoisophthalate: 12 mol%

(diol component)

A compound obtained by adding 2 moles of ethylene oxide to 1 mole of bisphenol S: 86 mole%

Ethylene glycol: 14 mol%.

(Reference Example 13)

Preparation of water dispersion of polyester resin (b-12) having no naphthalene skeleton

Water dispersion of polyester resin comprising the following copolymer composition

<Copolymerization component>

(dicarboxylic acid component)

Terephthalic acid: 88 mol%

Dimethyl sodium 5-sulfoisophthalate: 12 mol%

(diol component)

A compound obtained by adding 2 moles of ethylene oxide to 1 mole of bisphenol S: 86 mole%

Ethylene glycol: 14 mol%.

(Example 1)

A coating composition was prepared as follows.

Aqueous dispersion of acrylic/urethane copolymer resin (a): "Sannaron" WG-658 manufactured by Sannan Kosei Chemical Co., Ltd. (solid content concentration: 30% by weight)

Aqueous dispersion of polyester resin (b): polyester resin (b-1) (solid content concentration: 15% by weight)

Aqueous dispersion of isocyanate compound (c): Daiichi Kogyo Seyaku Co., Ltd. "Elastron" (registered trademark) E-37 (solid content concentration 28% by weight)

Aqueous dispersion of oxazoline compound (d-1): "Epocross" WS-500 manufactured by Nippon Shokubai Co., Ltd. (solid content concentration: 40 wt%)

Water-based solvent (f): pure water

(a) to (d) above (a)/(b)/(c)/(d) = 15/85/10/40 in the solid content weight ratio, and the solid content concentration of the coating composition was 8.5 wt% The concentration was adjusted by mixing (f) as much as possible. The resin composition in the coating composition at this time is shown in Table 1-1.

Subsequently, after sufficiently vacuum-drying PET pellets (intrinsic viscosity 0.63 dl/g) substantially free of particles, it is supplied to an extruder and melted at 285°C, extruded from a T-shaped nozzle into a sheet shape, and electrostatic applied casting method It was wound on a mirror casting drum with a surface temperature of 25° C. and solidified by cooling. This unstretched film was heated at 90 degreeC, and it extended|stretched 3.4 times in the longitudinal direction, and it was set as the uniaxially stretched film (B film). This film was corona-discharge-treated in air.

Next, the coating composition adjusted to the concentration in an aqueous solvent was applied to the corona discharge-treated surface of the uniaxially oriented film by bar coating. Both ends of the uniaxially oriented film coated with the coating composition adjusted in concentration with a water-based solvent are gripped with clips and guided to the preheating zone, and the ambient temperature is set to 75° C. The coating composition was dried at a concentration of an aqueous solvent at an atmospheric temperature of 90°C and then dried to form a resin layer (X). Then, continuously stretched 3.5 times in the width direction in a heating zone (stretching zone) at 120 ° C., heat treatment is performed for 20 seconds in a heat treatment zone (heat setting zone) at 230 ° C., and crystal orientation is completed. got a film. In the obtained laminated polyester film, the thickness of PET film was 100 micrometers. In addition, the resin layer (X) is a composition which contains an acrylic structure (A), a urethane structure (B), and a naphthalene structure (C) from the composition of a coating composition, and does not contain a carbodiimide structure (D).

The characteristics of the obtained laminated polyester film, etc. are shown in Table 2-1. The haze is low and the transparency is excellent, the initial adhesion with the hard coating layer, the heat-and-moisture adhesion are excellent, and the reflectance change amount ΔR before and after the boiling treatment test is small, the boiling resistance adhesion, UV adhesion resistance, hot water transparency, The oligomer suppression property and visibility were favorable.

(Examples 2 to 3)

Using the following melamine compound (e), the laminated polyester film was obtained by the method similar to Example 1 except having changed the solid content weight ratio of (e) to the numerical value of Table 1-1. The characteristics of the obtained laminated polyester film, etc. are shown in Table 2-1. By containing a melamine compound compared with Example 1, the reflectance change amount ΔR before and after the boiling treatment test is small, boiling resistance, UV adhesion resistance, excellent transparency, initial adhesion, moisture and heat resistance, It showed the transparency of hot water, oligomer suppression property, and visibility.

Water dispersion of melamine compound (e): Sanwa Chemical Co., Ltd. "Nikalac" (registered trademark) MW12LF (solid content concentration: 71% by weight)

(Example 4)

The laminated polyester film was obtained by the method similar to Example 3 except having changed the solid content weight ratio of a melamine compound (e) to the numerical value of Table 1-1. The characteristics of the obtained laminated polyester film, etc. are shown in Table 2-1. By increasing the content of the melamine compound (e) compared to Example 3, the initial haze is slightly higher, the reflectance change amount ΔR before and after the boiling treatment test, the dispersion index slightly increases, transparency, boiling resistance, UV adhesion resistance Although it fell slightly, it was favorable and showed the equivalent initial stage adhesiveness, moist-and-heat-resistance adhesiveness, hot-water transparency, oligomer suppression property, and visibility.

(Example 5)

A laminated polyester film was obtained by the method similar to Example 3 except having used the polyester resin (b-2) as a polyester compound (b). The characteristics of the obtained laminated polyester film, etc. are shown in Table 2-1.

By using the polyester resin (b-2) with a small content of the aromatic dicarboxylic acid component containing a sulfonic acid metal base as compared with Example 3, the initial haze is slightly higher, and the reflectance change amount ΔR before and after the boiling treatment test, dispersion The index slightly increased, and transparency, boiling resistance, UV adhesiveness, and hot water transparency were slightly lowered, but were good, and showed equivalent initial adhesiveness, heat-and-moisture adhesiveness, oligomer suppression property, and visibility.

(Examples 6 to 7)

As the polyester compound (b), the polyester resin (b-3) (Example 6) and the polyester resin (b-4) (Example 7) were used in the same manner as in Example 3, except that the laminated polyester film was used. got The characteristics of the obtained laminated polyester film, etc. are shown in Table 2-1. Compared with Example 3, by using a polyester resin with a large content of the aromatic dicarboxylic acid component containing a sulfonic acid metal base, the initial haze is slightly lower, the reflectance change amount ΔR before and after the boiling treatment test is equal, but the dispersion index is It became smaller and showed equivalent excellent initial stage adhesiveness, heat-and-moisture adhesiveness, boiling-resistant adhesiveness, UV-resistance resistance, hot water transparency, oligomer suppression property, and visibility.

(Example 8)

A laminated polyester film was obtained by the method similar to Example 3 except having used the polyester resin (b-5) as a polyester compound (b). The characteristics of the obtained laminated polyester film, etc. are shown in Table 2-1. Compared with Example 3, by using a polyester resin with a large content of the aromatic dicarboxylic acid component containing a sulfonic acid metal base, the initial haze is slightly higher, the reflectance change amount ΔR before and after the boiling treatment test, and the dispersion index become larger, Transparency, visibility, initial adhesiveness, boiling resistance, UV resistance, hot water transparency, and oligomer suppression properties were slightly inferior, but good.

(Example 9)

A laminated polyester film was obtained by the method similar to Example 3 except having used the polyester resin (b-6) as a polyester compound (b). The characteristics of the obtained laminated polyester film, etc. are shown in Table 2-1. Compared with Example 3, by using a polyester resin that does not contain an aromatic dicarboxylic acid component containing a sulfonic acid metal base, the initial haze is slightly higher, the reflectance change amount ΔR before and after the boiling treatment test, and the dispersion index become larger, Transparency, visibility, initial adhesion, boiling resistance, UV resistance, hot water transparency, and oligomer properties were slightly inferior, but good.

(Examples 10 to 11)

The laminated polyester film was carried out in the same manner as in Example 3 except that the polyester resin (b-7) (Example 10) and the polyester resin (b-8) (Example 11) were used as the polyester compound (b). got

The characteristics of the obtained laminated polyester film, etc. are shown in Table 2-1. By using a polyester resin having a different bisphenol S skeleton as compared with Example 3, the oligomer suppression property was slightly lowered, but it was good, and the reflectance change amount ΔR before and after the boiling treatment test was small, and the same excellent initial adhesiveness, heat and moisture resistance Adhesiveness, boiling-resistant adhesiveness, UV-resistance adhesiveness, hot water-resistant transparency, and visibility were shown.

(Example 12)

The laminated polyester film was obtained by the method similar to Example 3 except having changed the solid content weight ratio of an isocyanate compound (c) into the numerical value of Table 1-1. The characteristics of the obtained laminated polyester film, etc. are shown in Table 2-1. By reducing the content of the isocyanate compound (c) as compared with Example 3, the reflectance change amount ΔR before and after the boiling treatment test slightly increases, initial adhesion, heat-and-moisture adhesion, boiling-resistant adhesion, UV-resistance, heat-resistant water Although transparency fell slightly, it showed equivalent transparency, oligomer suppression property, and visibility.

(Examples 13 to 14)

The laminated polyester film was obtained by the method similar to Example 3 except having changed the solid content weight ratio of an isocyanate compound (c) into the numerical value of Table 1-1. The characteristics of the obtained laminated polyester film, etc. are shown in Table 2-1. By increasing the content of the isocyanate compound (c) in comparison with Example 3, equivalent transparency, excellent initial adhesion, heat-and-moisture adhesion, boiling-resistant adhesion, UV adhesion, hot water transparency, oligomer inhibition, visibility showed

(Example 15)

A laminated polyester film was obtained in the same manner as in Example 3 except that the solid content weight ratio of the oxazoline compound (d) was changed to the numerical value shown in Table 1-1. The characteristics of the obtained laminated polyester film, etc. are shown in Table 2-1. By reducing the content of the oxazoline compound (d) compared with Example 3, the reflectance change amount ΔR before and after the boiling treatment test slightly increased, initial adhesion, heat-and-moisture adhesion, boiling resistance, UV adhesion, Although the oligomer suppression property fell slightly, it was favorable and showed equivalent transparency, visibility, and hot water transparency.

(Example 16)

A laminated polyester film was obtained in the same manner as in Example 3 except that the solid content weight ratio of the oxazoline compound (d) was changed to the numerical value shown in Table 1-1. The characteristics of the obtained laminated polyester film, etc. are shown in Table 2-1. By increasing the content of the oxazoline compound (d) as compared with Example 3, equivalent excellent transparency, initial adhesion, heat-and-moisture adhesion, boiling-resistant adhesion, UV resistance, visibility, hot water transparency, oligomer inhibition showed

(Example 17)

The laminated polyester film was obtained by the method similar to Example 3 except having used the following oxazoline compound (d-2) as an oxazoline compound (d). The characteristics of the obtained laminated polyester film, etc. are shown in Table 2-1. Compared with Example 3, even when using an oxazoline compound (d-2) having a different terminal structure and polymerization degree, the same transparency, initial adhesion, heat-and-moisture adhesion, boiling-resistance adhesion, UV resistance, visibility, heat resistance It showed transparency and oligomer suppression property.

Aqueous dispersion of oxazoline compound (d-2): "Epocross" WS-700 manufactured by Nippon Shokubai Co., Ltd. (solid content concentration: 40 wt%)

(Examples 18 to 19)

A laminated polyester film was obtained in the same manner as in Example 3 except that the solid content weight ratio of the acrylic/urethane copolymer resin (a) and the polyester resin (b) was changed to the numerical value shown in Table 1-1. The characteristics of the obtained laminated polyester film, etc. are shown in Table 2-1. Compared with Example 3, acrylic urethane copolymer resin (a) / polyester resin (b) = 40/60 (Example 18), acrylic urethane copolymer resin (a) / polyester resin (b) = 30/70 By setting it as (Example 19), although the reflectance change amount (DELTA)R before and behind a boiling process test, and a dispersion index became slightly large, reflectance decreased slightly, and haze increased slightly, it was favorable. Moreover, although boiling-resistance adhesiveness, UV-resistance resistance, oligomer suppression property, and visibility fell slightly, it was favorable, and showed the equivalent initial stage adhesiveness, heat-and-moisture-resistance adhesiveness, and hot water transparency.

(Example 20)

A laminated polyester film was obtained in the same manner as in Example 3 except that the solid content weight ratio of the acrylic/urethane copolymer resin (a) and the polyester resin (b) was changed to the numerical value shown in Table 1-1. The characteristics of the obtained laminated polyester film, etc. are shown in Table 2-1. Compared with Example 3, even when the acrylic/urethane copolymer resin (a)/polyester resin (b) = 20/80, the reflectance change amount ΔR before and after the boiling treatment test and the oligomer inhibitory property slightly increased, but equal transparency and excellent Initial adhesiveness, heat-and-moisture adhesiveness, boiling-resistance adhesiveness, UV-resistance adhesiveness, hot water resistance transparency, and visibility were shown.

(Example 21)

A laminated polyester film was obtained in the same manner as in Example 3 except that the solid content weight ratio of the acrylic urethane copolymer resin (a) and the polyester resin (b) was changed to the numerical value shown in Table 1-2. The characteristics of the obtained laminated polyester film, etc. are shown in Table 2-2. Compared with Example 3, by setting the acrylic urethane copolymer resin (a)/polyester resin (b) = 5/95, the dispersion index becomes slightly small, the haze decreases slightly, the reflectance slightly increases, transparency and oligomer suppression. The castle was good. In addition, since the reflectance change amount ΔR before and after the boiling treatment test slightly increased, initial adhesiveness, heat-and-moisture adhesiveness, boiling-resistance adhesiveness, UV-resistance resistance, hot water transparency, and visibility fell slightly, but were good.

(Example 22)

The laminated polyester film was obtained by the method similar to Example 3 except having adjusted the solid content weight ratio of the isocyanate compound (c) to the numerical value of Table 1-2. The characteristics of the obtained laminated polyester film, etc. are shown in Table 2-2. By reducing the content of the isocyanate compound (c) as compared with Example 3, transparency, visibility, and oligomer suppression properties were excellent, and the reflectance change amount ΔR before and after the boiling treatment test slightly increased, so initial adhesiveness, heat-and-moisture adhesiveness , boiling-resistance adhesiveness, UV-resistance resistance, and hot water transparency were slightly deteriorated, but were good.

(Example 23)

The laminated polyester film was obtained by the method similar to Example 3 except having adjusted the solid content weight ratio of the isocyanate compound (c) to the numerical value of Table 1-2. The characteristics of the obtained laminated polyester film, etc. are shown in Table 2-2. As compared with Example 3, when content of an isocyanate compound (c) increased, the haze slightly increased, and although transparency and oligomer suppression property fell slightly, it was favorable. Moreover, since the reflectance change amount (DELTA)R before and behind a boiling treatment test was equal, it showed equivalent initial stage adhesiveness, moist-and-heat-resistance adhesiveness, boiling-resistant adhesiveness, UV-resistant adhesiveness, and hot water transparency.

(Example 24)

The laminated polyester film was obtained by the method similar to Example 3 except having adjusted the solid content weight ratio of an oxazoline compound (d) to the numerical value of Table 1-2. The characteristics of the obtained laminated polyester film, etc. are shown in Table 2-2. Compared with Example 3, since the content of the oxazoline compound (d) decreased, the oligomer suppression property was slightly reduced, but it was good, and the reflectance change amount ΔR before and after the boiling treatment test slightly increased, so initial adhesiveness, heat-and-moisture adhesion Although the property, boiling-resistance adhesiveness, UV-resistance resistance, and hot water transparency slightly fell, it was favorable.

(Example 25)

The laminated polyester film was obtained by the method similar to Example 3 except having adjusted the solid content weight ratio of an oxazoline compound (d) to the numerical value of Table 1-2. The characteristics of the obtained laminated polyester film, etc. are shown in Table 2-2. As compared with Example 3, when content of an oxazoline compound (d) increased, the haze slightly increased, and although transparency fell slightly, it was favorable. Moreover, since the reflectance change amount (DELTA)R before and behind a boiling treatment test was equal, it showed equivalent initial stage adhesiveness, moist-and-heat-resistance adhesiveness, boiling-proof adhesiveness, UV-resistance resistance, hot water transparency, and oligomer suppression.

(Example 26)

The laminated polyester film was obtained by the method similar to Example 3 except having adjusted the solid content weight ratio of a melamine compound (e) to the numerical value of Table 1-2. The characteristics of the obtained laminated polyester film, etc. are shown in Table 2-2. As compared with Example 3, when content of a melamine compound (e) decreased, the excellent transparency, initial stage adhesiveness, heat-and-moisture-resistance adhesiveness, and oligomer suppression were exhibited equally. Moreover, since the reflectance change amount (DELTA)R before and behind a boiling treatment test slightly increased, although boiling-resistant adhesiveness, UV-resistant adhesiveness, and hot water transparency fell slightly, it was favorable.

(Example 27)

The laminated polyester film was obtained by the method similar to Example 3 except having adjusted the solid content weight ratio of a melamine compound (e) to the numerical value of Table 1-2. The characteristics of the obtained laminated polyester film, etc. are shown in Table 2-2. Compared with Example 3, when content of a melamine compound (e) increased, a dispersion index became slightly large, and although haze became slightly high, it was favorable. Moreover, although the reflectance change amount (DELTA)R before and behind a boiling process test became large slightly, boiling-resistant adhesiveness and UV-resistant adhesiveness fell slightly, it was favorable.

(Example 28)

A laminated polyester film was obtained by the method similar to Example 3 except having used the polyester resin (b-9) as a polyester compound (b). The characteristics of the obtained laminated polyester film, etc. are shown in Table 2-2. Compared with Example 3, by using a polyester resin having a bisphenol A skeleton, the initial haze is slightly higher, the reflectance change amount ΔR before and after the boiling treatment test, the dispersion index is slightly large, the reflectance is small, transparency, visibility, resistance Although boiling adhesiveness, UV adhesiveness, and oligomer suppression property fell slightly, the outstanding initial stage adhesiveness and moist-and-heat-resistance adhesiveness were shown.

(Example 29)

A laminated polyester film was obtained by the method similar to Example 3 except having used the polyester resin (b-10) as a polyester compound (b). The characteristics of the obtained laminated polyester film, etc. are shown in Table 2-2. By using a polyester resin having a skeleton of bisphenol A compared with Example 3, the initial haze is slightly higher, the reflectance change amount ΔR before and after the boiling treatment test, the dispersion index, the oligomer suppression property is slightly high, the reflectance becomes small, and the transparency , visibility, boiling-resistance adhesiveness, and UV-resistance adhesiveness were slightly lowered, but exhibited equivalent excellent initial adhesiveness and heat-and-moisture adhesiveness.

(Example 30)

A laminated polyester film was obtained by the method similar to Example 1 except having used the polyester resin (b-2) as a polyester compound (b). The characteristics of the obtained laminated polyester film, etc. are shown in Table 2-2.

By using the polyester resin (b-2) with a small content of the aromatic dicarboxylic acid component containing a sulfonic acid metal base as compared with Example 1, the initial haze is slightly high, the dispersion index is slightly increased, transparency, and boiling resistance Adhesiveness, UV-resistance, heat-resistance transparency, and oligomer suppression properties were slightly lowered, but were good, and the reflectance change amount ΔR before and after the boiling treatment test was excellent, and showed equivalent initial adhesiveness, heat-and-moisture adhesiveness, and visibility.

(Examples 31 to 33)

A polyester resin (b-2) was used as the polyester compound (b), and the solid content weight ratio of the acrylic/urethane copolymer resin (a) and the polyester resin (b) was changed to the numerical value shown in Table 1-2. The laminated polyester film was obtained by the method similar to Example 3. The characteristics of the obtained laminated polyester film, etc. are shown in Table 2-2. By using the polyester resin (b-2) with a small content of the aromatic dicarboxylic acid component containing the sulfonic acid metal base as compared with Example 3, the acrylic/urethane copolymer resin (a)/polyester resin (b) = 40/60 (Example 31), acrylic urethane copolymer resin (a) / polyester resin (b) = 30/70 (Example 32), acrylic urethane copolymer resin (a) / polyester resin (b) = By setting it as 20/80 (Example 33), the dispersion index slightly increased, the reflectance slightly decreased, the haze slightly increased, and the oligomer suppression property was slightly lowered, but it was good. In addition, the reflectance change amount ΔR before and after the boiling treatment test was slightly increased, and although boiling resistance, UV resistance, and visibility were slightly lowered, it was good, and showed equivalent initial adhesiveness, moisture and heat resistance, and transparency with hot water.

(Example 34)

The laminated polyester film was obtained by the method similar to Example 3 except having changed the film thickness of resin layer (X). The characteristics of the obtained laminated polyester film, etc. are shown in Table 2-2. By reducing the film thickness of the resin layer (X) compared with Example 3, the reflectance is lowered, the visibility is slightly lowered, the oligomer suppression property is slightly lowered, but it is good, and the initial adhesion property, the heat-and-moisture resistance, and resistance are good. Boiling adhesiveness, UV adhesiveness-resistance, and hot water transparency were shown.

(Comparative Example 1)

The laminated polyester film was obtained by the method similar to Example 1 except having adjusted the solid content weight ratio of (a)-(e) to the numerical value of Table 1-3. The characteristics of the obtained laminated polyester film, etc. are shown in Table 2-3. The laminated polyester film of Comparative Example 1 did not contain an acrylic urethane copolymer resin, and thus exhibited excellent transparency and oligomer suppression properties equivalent to those of Example 1, but the amount of change in reflectance before and after the boiling treatment test ΔR, initial adhesiveness, The performance was inferior in heat-and-moisture adhesiveness, boiling-resistant adhesiveness, UV-resistance adhesiveness, and visibility.

(Comparative Examples 2-3)

The laminated polyester film was obtained by the method similar to Example 3 except having adjusted the solid content weight ratio of (a)-(e) to the numerical value of Table 1-3. The characteristics of the obtained laminated polyester film, etc. are shown in Table 2-3. The laminated polyester films of Comparative Examples 2 and 3 did not contain the polyester resin (b) having a naphthalene skeleton, so that the amount of change in reflectance before and after the boiling treatment test equivalent to that of Example 3 ΔR, transparency, initial adhesion, Although heat-and-moisture adhesiveness, boiling-resistance adhesiveness, UV-resistance resistance, and oligomer suppression were shown, it was inferior in performance in visibility.

(Comparative Examples 4 to 5)

The laminated polyester film was obtained by the method similar to Example 3 except having adjusted the solid content weight ratio of (a)-(e) to the numerical value described in a table|surface. The characteristics of the obtained laminated polyester film, etc. are shown in Table 2-3.

By not containing the isocyanate compound (c), the laminated polyester film of Comparative Example 4 exhibits excellent transparency, good visibility, and oligomer suppression properties equivalent to those of Example 3, but the reflectance change amount ΔR before and after the boiling treatment test, resistance The performance was inferior in wet-heat adhesiveness, boiling-resistance adhesiveness, and UV-resistance adhesiveness.

In addition, the laminated polyester film of Comparative Example 5 did not contain the oxazoline compound (d), and thus exhibited excellent transparency and good visibility equivalent to those of Example 3, but the reflectance change amount ΔR before and after the boiling treatment test, initial adhesion The performance was inferior in property, heat-and-moisture adhesiveness, boiling-resistance adhesiveness, UV-resistance resistance, hot water-resistant transparency, and oligomer suppression property.

(Comparative Examples 6 to 9)

The laminated polyester film was obtained by the method similar to Example 3 except having changed the solid content weight ratio of the acrylic urethane copolymer resin (a) and the polyester resin (b) to the numerical value of Table 1-3. The characteristics of the obtained laminated polyester film, etc. are shown in Table 2-3.

Compared with Example 3, the laminated polyester film of Comparative Example 6 had an acrylic urethane copolymer resin (a)/polyester resin (b) = 50/50, so that the dispersion index became 7, and the haze slightly increased, The reflectance was reduced. In addition, although it exhibits equivalent excellent initial adhesiveness and heat-and-moisture adhesiveness, the reflectance change amount ΔR before and after the boiling treatment test, boiling resistance, UV adhesiveness, hot water transparency, oligomer suppression property, and visibility were inferior.

As for the laminated polyester film of Comparative Example 7, compared with Example 3, the dispersion index becomes large by 10 by setting it as acrylic urethane copolymer resin (a)/polyester resin (b) = 60/40, reflectance falls, and haze increased, and transparency decreased. In addition, although it shows the same initial adhesiveness and heat-and-moisture-resistance adhesiveness, the reflectance change amount ΔR before and after the boiling treatment test, boiling resistance, UV adhesion resistance, hot water transparency, oligomer suppression property, and visibility were inferior.

As for the laminated polyester film of Comparative Example 8, as compared with Example 3, by setting it as acrylic urethane copolymer resin (a)/polyester resin (b) = 80/20, the dispersion index becomes large to 15, reflectance falls, and haze increased, and transparency decreased. In addition, although it shows the same initial adhesiveness and heat-and-moisture-resistance adhesiveness, the reflectance change amount ΔR before and after the boiling treatment test, boiling resistance, UV adhesion resistance, hot water transparency, oligomer suppression property, and visibility were inferior.

As for the laminated polyester film of Comparative Example 9, when the acrylic urethane copolymer resin (a)/polyester resin (b) = 90/10, the dispersion index became 20, the reflectance decreased, the haze increased, and the transparency was it became falling In addition, although it shows the same initial adhesiveness and heat-and-moisture-resistance adhesiveness, the reflectance change amount ΔR before and after the boiling treatment test, boiling resistance, UV adhesion resistance, hot water transparency, oligomer suppression property, and visibility were inferior.

(Comparative Examples 10 to 11)

A laminated polyester film was obtained in the same manner as in Example 3 except that the following carbodiimide compound (g) was used and the solid content weight ratio of (g) was changed to the numerical value shown in Table 1-3. The characteristics of the obtained laminated polyester film, etc. are shown in Table 2-3. By containing the carbodiimide compound as compared with Example 3, the transparency, initial adhesion, heat-and-moisture-resistance adhesiveness, hot water transparency, and visibility were the same as in Example 3, but the polyester resin (b) and the isocyanate compound Since reaction of (c), an oxazoline compound (d), and a melamine compound (e) was inhibited, a resin layer with a high degree of crosslinking could not be formed, and it was inferior in oligomer suppression property.

Aqueous dispersion of carbodiimide compound (g): Nisshinbo Chemical Co., Ltd. "Carbodilite" V-04 (solid content concentration: 40 wt%)

[Table 1-1]

[Table 1-2]

[Table 1-3]

[Table 2-1]

[Table 2-2]

[Table 2-3]

The present invention is a laminated polyester film having a resin layer that is excellent not only in initial adhesiveness but also in particularly moist and heat-resistance, boiling-resistance, and hot-water transparency, and excellent in suppression of interference fringes when a hard coat layer is laminated. It relates to an easy-to-adhesive film for optical use for various display uses, an easy-to-adhesive film for hard coating films used for industrial purposes such as window glass of automobiles and buildings, and construction materials, and also excellent in adhesion with various laminates such as inks Available for easy-to-adhesive films.

1: resin layer (X)
2: polyester film
3: X direction
4: Y direction
5: Z direction

Claims (10)

on at least one side of the polyester film
A laminated polyester film having a resin layer (X), comprising:
The resin layer (X)
an acrylic structure (A), a urethane structure (B), and a naphthalene structure (C);
does not contain a carbodiimide structure (G);
The resin layer (X)
Acrylic-urethane copolymer resin (a) and
A polyester resin (b) having a naphthalene skeleton and
isocyanate compound (c) and
It is a layer formed using a coating composition comprising an oxazoline compound (d),
The solid content weight ratio of the acrylic urethane copolymer resin (a) and the polyester resin (b) in the coating composition is 40/60 to 5/95,
The change amount ΔR of the spectral reflectance before and after the boiling treatment test on the side of the resin layer (X) is 0% or more and 2% or less. The laminated polyester film of Claim 1 whose surface zeta potential of the said resin layer (X) is -20 mV or more. The minimum value of the spectral reflectance in the wavelength range of wavelength 450nm or more and 650 nm or less on the said resin layer (X) side is 4.5 % or more and 6.0 % or less, The laminated polyester film of Claim 1 or 2 characterized by the above-mentioned. The dispersion index according to claim 1, wherein the agglomerate containing the acrylic/urethane copolymer resin (a) of the resin layer (X) has a dispersion index of 5 or less, and
The ratio of the acrylic urethane copolymer resin (a) in the said coating composition is 3 weight% or more, The laminated polyester film characterized by the above-mentioned. 5. The polyester resin (b) according to any one of claims 1, 2 and 4, wherein the aromatic dicarboxylic acid component containing a sulfonic acid metal base is added to all the dicarboxylic acid components of the polyester. It is a copolyester resin containing 1-30 mol%, The laminated polyester film characterized by the above-mentioned. The laminated polyester film according to any one of claims 1 to 4, wherein the polyester resin (b) contains a diol component represented by the following formula (1).

(wherein, X ¹ , X ² : represents -(C _n H _2n O) _m -H (an integer of n=2 or more and 4 or less, m=1 or more and 15 or less)) The method according to any one of claims 1, 2 and 4, wherein the solid content weight ratio of the acrylic/urethane copolymer resin (a) and the polyester resin (b) in the coating composition is 20/80 to 5/95. Laminated polyester film characterized in that. The method according to claim 7, wherein in the coating composition, when the total of the solid content of the acrylic/urethane copolymer resin (a) and the polyester resin (b) is 100 parts by weight,
3 to 20 parts by weight of the isocyanate compound (c) by solid content,
A laminated polyester film comprising 20 to 50 parts by weight of the oxazoline compound (d) by solid content. The coating composition according to claim 8, wherein when the total of the solid content of the acrylic/urethane copolymer resin (a) and the polyester resin (b) is 100 parts by weight, 5 to 30 parts by weight of the melamine compound (e) Laminated polyester film comprising. delete

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