JP2023111662A - polyester film roll - Google Patents

Abstract

To provide a polyester film roll which has a cured resin layer having an uneven structure, can adequately control a surface shape, has a good air leakage index, minimizes occurrence of wrinkles, improves roll winding property, and thereby can cope with a long size.SOLUTION: A polyester film roll is obtained by winding a laminated polyester film having a polyester film, and a cured resin layer on one surface of the polyester film, wherein the laminated polyester film satisfies all the following (1) to (4). (1) The cured resin layer has an uneven structure. (2) The cured resin layer is a cured product of a cured resin composition containing (A) a release agent, (B) a crosslinking agent, and (D) fine particles. (3) Average surface roughness (Sa) of the surface of the cured resin layer is 1-9 nm. (4) A root-mean-square gradient (Sdq) of the surface of the cured resin layer is 0.40-0.80.

Description

TECHNICAL FIELD The present invention relates to a polyester film roll, and for example, to a polyester film roll suitable as a support for a process release film used in the manufacturing process of laminated ceramic capacitors.

2. Description of the Related Art In recent years, with the increasing use of electronics in automobiles and the increasing functionality of smartphones, multi-layered-ceramic-capacitors (MLCCs) are becoming smaller and higher in capacity.
A multilayer ceramic capacitor is manufactured as follows.
First, a ceramic slurry containing a ceramic component and a binder resin is applied onto a release film and dried to prepare a ceramic green sheet (dielectric sheet), on which electrodes are printed by screen printing or the like. After drying, the printed ceramic green sheets are peeled off from the release film to form internal electrodes, and a large number of such green sheets are laminated. After the laminated green sheets are pressed and integrated, they are cut into individual chips.
Then, the internal electrodes and dielectric layers are sintered in a kiln to manufacture a multilayer ceramic capacitor.

In order to reduce the size and increase the capacity of MLCCs, ceramic green sheets are becoming thinner. When the thinning of the ceramic green sheet further progresses to 0.5 μm (thickness after drying) or less, if there are minute projections on the surface of the release film as a carrier film, pinholes may occur in the ceramic green sheet due to this. etc. occur. Therefore, the release film is required to have a higher surface smoothness.

Conventionally, as a support for this type of release film, Patent Document 1 discloses a substrate having a first surface and a second surface, and a smooth film provided on the first surface side of the substrate. and a release agent layer provided on the side of the smoothing layer opposite to the substrate, wherein the smoothing layer contains a thermosetting compound having a mass average molecular weight of 950 or less. A release film for green sheet production is disclosed which is formed by heating and curing a layer-forming composition. In the release film, the outer surface of the release agent layer has an arithmetic mean roughness Ra1 of 8 nm or less and a maximum peak height Rp1 of the outer surface of the release agent layer of 50 nm or less. there is

Further, in Patent Document 2, as a release polyester film with excellent surface smoothness and particularly few fine defects on the film surface, the number of depression defects with a depth of 0.5 μm or more is 5/m ² or less. , a releasing polyester film having a center line average roughness SRa of 15 to 35 nm and a ten-point average roughness SRz of 1000 nm or less on at least one surface.

As the thinning of green sheets progresses, there is a growing demand for higher lamination accuracy when laminating thinned green sheets into multiple layers. For this reason, the importance of the flatness of the release film is increasing, and efforts are being made to control heat wrinkles and the like.

As a film of this kind, Patent Document 3 discloses a polyester film roll obtained by winding a polyester film, wherein the polyester film has less than 5 slack defects per 100 m ² . It is

JP 2014-177093 A JP 2013-7054 A Japanese Unexamined Patent Application Publication No. 2002-273719

As ceramic green sheets become thinner, dielectric layers are required to have higher smoothness. However, along with the high smoothness of the polyester film, if the production speed is increased or the film winding length is increased in order to improve productivity during the manufacturing process, the windability of the film roll will be improved. There were problems such as being difficult to apply and wrinkles easily occurring.

Therefore, an object of the present invention is to provide a polyester film roll that is highly smooth, does not easily wrinkle, has good winding properties, and can be made longer. .

The present inventors have made intensive studies in view of the above circumstances, and as a result, have found that the above problems can be easily solved by using a polyester film roll having a specific configuration, and have completed the present invention. That is, the present invention provides the following [1] to [17].
[1] A polyester film roll obtained by winding a polyester film and a laminated polyester film having a cured resin layer on one side of the polyester film,
A polyester film roll in which the laminated polyester film satisfies all of the following requirements (1) to (4).
(1) The cured resin layer has an uneven structure.
(2) The cured resin layer is a cured product of a cured resin composition containing (A) a release agent, (B) a cross-linking agent, and (D) fine particles.
(3) The average surface roughness (Sa) of the surface of the cured resin layer is 1 to 9 nm.
(4) The root-mean-square gradient (Sdq) of the cured resin layer surface is 0.40 to 0.80.
[2] The polyester film roll according to [1], wherein the ratio (Sp/Sa) between the maximum peak height (Sp) and the average surface roughness (Sa) of the surface of the cured resin layer is 30 or less.
[3] The polyester film roll according to any one of [1] or [2], wherein the height (Spk) of protruded peaks on the surface of the cured resin layer is 70 nm or more.
[4] The polyester film roll according to any one of [1] to [3], wherein the cured resin composition contains (C) a binder resin.
[5] (B) The polyester film roll of [4], wherein the binder resin contains one or more selected from the group consisting of (meth)acrylic resin and polyvinyl alcohol.
[6] The polyester film roll according to any one of [1] to [5], wherein the cured resin layer has a thickness of 0.02 to 0.15 g/m ² in weight per unit area.
[7] The polyester film roll according to any one of [1] to [6], wherein the content of (A) the release agent in the cured resin composition is 5 to 90% by mass as a non-volatile component.
[8] The polyester film is a polyester film having at least a three-layer structure having a surface layer, an intermediate layer, and a surface layer in this order, and the cured resin layer is provided so as to be in contact with one of the surface layers. The polyester film roll according to any one of [1] to [7].
[9] The polyester film roll according to any one of [1] to [8], wherein the intrinsic viscosity (IV) of the polyester constituting the surface layer of the polyester film is 0.50 dL/g or more.
[10] The polyester film roll according to any one of [1] to [9], wherein the surface layer of the polyester film contains a titanium compound.
[11] The polyester film according to any one of [1] to [10], wherein the surface layer of the polyester film contains at least one of an antimony compound and a titanium compound, and the content of the antimony compound is 100 ppm or less. roll.
[12] The polyester film roll according to any one of [1] to [11], wherein one surface layer of the polyester film contains substantially no particles.
[13] The polyester film roll of [12], wherein the other surface layer of the polyester film contains substantially no particles.
[14] Any one of [1] to [13], wherein in the polyester film, the average surface roughness (Sa) of the surface layer opposite to the surface on which the cured resin layer is provided is 0.1 to 9 nm A polyester film roll as described.
[15] The polyester film roll according to any one of [1] to [14], which has a release layer on the film surface opposite to the surface on which the cured resin layer is provided.
[16] The polyester film roll according to any one of [1] to [15], which is used as a support for ceramic green sheets in the manufacturing process of multilayer ceramic capacitors.
[17] The polyester film roll according to any one of [1] to [16], which is used as a support for ceramic green sheets in the manufacturing process of ceramic capacitors for automobiles.

ADVANTAGE OF THE INVENTION According to this invention, while having high smoothness, wrinkles are hard to generate|occur|produce, the windability of a film roll is favorable, and the polyester film roll which can respond to lengthening can be provided.

In addition, since the polyester film roll of the present invention has extremely excellent surface smoothness, when the film is used as a support for a ceramic green sheet in, for example, the manufacturing process of a laminated ceramic capacitor, fine fine grains on the film surface can be obtained. There is an advantage that there is little possibility that defects will occur in the ceramic green sheets due to unevenness.

In addition, the polyester film roll of the present invention has extremely excellent surface smoothness, and the surface of the cured resin layer has a characteristic concave-convex shape, so that wrinkle prevention is excellent. Therefore, if the film is used as a support for a ceramic green sheet, for example, in the manufacturing process of a laminated ceramic capacitor, a uniform dielectric layer can be formed by uniformly applying the ceramic slurry, and the film roll can be used. Since the winding property is good, wrinkles are less likely to occur, and it can contribute to the improvement of productivity due to the reduction in switching frequency accompanying the lengthening of polyester film rolls.
In particular, it can be suitably used as a support for a ceramic green sheet used in multilayer ceramic capacitors for automobiles.

4 shows the surface shape of the cured resin layer obtained in Example 2. FIG. 2 shows the surface shape of a cured resin layer obtained in Comparative Example 1. FIG. The surface shape of a conventional film (particle kneaded) is shown.

Next, an example of an embodiment of the invention will be described. However, the present invention is not limited to the embodiments described below.

In this specification, when the expression "(meth)acryl" is used, "(meth)acryl" means one or both of "acryl" and "methacryl". Similarly, "(meth)acrylic acid" is one or both of "acrylic acid" and "methacrylic acid", "(meth)acrylate" is one or both of "acrylate" and "methacrylate", "(meth)acryloyl ” shall mean one or both of “acryloyl” and “methacryloyl”. Others are the same as above.

<Polyester film roll>
The polyester film roll of the present invention is a polyester film roll obtained by winding a polyester film and a laminated polyester film having a cured resin layer on one side of the polyester film, wherein the laminated polyester film is the following (1) It satisfies the requirements of (4).
(1) The cured resin layer has an uneven structure.
(2) The cured resin layer is a cured product of a cured resin composition containing (A) a release agent, (B) a cross-linking agent, and (D) fine particles.
(3) The average surface roughness (Sa) of the surface of the cured resin layer is 1 to 9 nm.
(4) The root-mean-square gradient (Sdq) of the cured resin layer surface is 0.40 to 0.80.

The polyester film roll of the present invention (hereinafter also referred to as "main roll") is a laminated polyester film having a cured resin layer (hereinafter sometimes simply referred to as "resin layer") and a polyester film in this order (hereinafter also referred to as "main film" It is a polyester film roll obtained by winding up a film.
This roll is a polyester film roll wound around a core such as a paper tube, a metal tube, a plastic tube, etc., and preferably has a width of 0.2 m or more, more preferably 0.3 m or more. 0 m or more is particularly preferable, and 1.5 m or more is most preferable. Although the upper limit of the width of the polyester film roll is not particularly limited, it is preferably 2.3 m or less, more preferably 2.0 m or less.
The length of the film wound on the roll is not particularly limited, but is preferably 1,000 m or longer, more preferably 6,000 m or longer, and still more preferably 12,000 m or longer.
Furthermore, the thickness of the present film is preferably 19 μm or more and 38 μm or less, more preferably 25 μm or more and 32 μm or less.

[Surface properties]
(1) Average surface roughness (Sa) of cured resin layer surface
The cured resin layer surface of this film has an average surface roughness (Sa) of 1 to 9 nm.
When the average surface roughness (Sa) of the surface of the cured resin layer of this film is greater than 9 nm, the smoothness of the surface of the cured resin layer is lost, and defects such as pinholes are likely to occur due to fine irregularities on the surface of the film. Become. On the other hand, when the average surface roughness (Sa) is less than 1 nm, the film surface becomes too flat and easily scratched.
The film preferably has an average surface roughness (Sa) of 2 to 7 nm on the surface of the cured resin layer, from the viewpoints of thinning the ceramic green sheet and suppressing pinholes.
In the present film, the surface on which the cured resin layer is provided is typically the surface opposite to the surface (processed surface) on which various materials are applied and laminated in the production of a ceramic layer, etc., as described later. (opposite side). However, even on the opposite surface, by reducing the average surface roughness (Sa) as described above, the unevenness of the opposite surface is transferred to the processed surface, and the transferred unevenness may cause pinholes. , it is possible to prevent the inability to respond to thinning.

Average surface roughness (Sa) is one of the surface roughness parameters (ISO 25178), and is a three-dimensional expansion of two-dimensional Ra (arithmetic mean roughness of lines). It is obtained by dividing the volume of the portion surrounded by the plane by the measurement area, and is obtained from the following formula (1).
When the surface is the XY plane and the height direction is the Z axis, A: the defined area (the entire image), Z (x, y): the height of the image point (x, y) from the plane of 0 The height is expressed as follows.

(2) root-mean-square gradient (Sdq)

The present inventors focused on the shape of the protrusions on the surface of the cured resin layer, particularly the inclined structure, and set the root-mean-square gradient (Sdq) to a certain value or more, so that when the film is wound into a roll, It has been found that good air leakage can be expressed, thereby improving windability.
The root-mean-square gradient (Sdq) is one of the surface roughness parameters obtained by measurement according to ISO25178, and is represented by the following formula (2).
The root-mean-square gradient (Sdq) represents the average magnitude of the local gradient of the unevenness of the surface, and the larger the value, the steeper the surface.

In the present invention, the root mean square gradient (Sdq) of the surface of the cured resin layer is required to be 0.40 to 0.80. If the root-mean-square gradient (Sdq) is more than 0.80, defects such as pinholes are likely to occur, the scratch resistance is lowered, and there is a possibility that the ceramic green sheet cannot be made thinner. If the root-mean-square gradient (Sdq) is less than 0.40, it becomes difficult to develop good air leakage between films, and it becomes difficult to improve windability. In addition, the film surface is extremely flattened so that the slipperiness of the film is reduced and the film is easily scratched.
On the other hand, by satisfying the above range, even in a long roll film, the protrusions on the surface of the cured resin layer are less likely to deform, and a good roll appearance can be obtained.
The root-mean-square gradient (Sdq) is more preferably 0.40 to 0.60 from the viewpoints of improving scratch resistance and coping with longer polyester film rolls and thinner ceramic green sheets.
In addition, when the cured resin layer contains the fine particles described later, the slope of the convex portion becomes steep, the root mean square gradient (Sdq) tends to be within the above-described predetermined range, and good air leakage between the films is achieved. can be expressed.

(3) Maximum peak height (Sp) of cured resin layer surface
From the viewpoint of suppressing pinholes, the maximum peak height (Sp) of the cured resin layer surface of the film is, for example, 150 nm or less, preferably 100 nm or less, and more preferably 80 nm or less. Although the lower limit of the maximum peak height (Sp) on the surface of the cured resin layer is not particularly limited, it is preferably 10 nm or more, more preferably 15 nm or more, and still more preferably 20 nm or more from the viewpoint of film handling.

The maximum peak height (Sp) is one of the surface roughness parameters (ISO 25178), represents the maximum value of the height from the average surface of the surface, and is represented by the following formula (3).

(4) Load length ratio (Rmr(80)) of cured resin layer surface
The load length ratio (Rmr(80)) of the roughness curve at a cutting level of 80% on the surface of the cured resin layer is preferably 50% or less, more preferably 45% or less, still more preferably 40% or less. Especially preferably, it is 35% or less. The lower limit of the load length ratio (Rmr(80)) is not particularly limited, and is about 1%, preferably 4%, more preferably 6%.
The present inventors considered that the load length ratio (Rmr(80)) is effective as an index representing the uneven distribution of the uneven structure. In the present invention, if the uneven shape of the surface is controlled so that the load length ratio (Rmr (80)) is 50% or less, an appropriate fine uneven structure is formed, so that the air between the films can be easily released. , wrinkles and the like do not occur, and the winding property is excellent, and a good roll appearance can be obtained.

The load length ratio (Rmr (c)) is one of the line roughness (JIS B 0601), and is an evaluation of the load length ML (c) of the contour element at the cutting level c (height% or μm) It represents the ratio to the length Ln and is obtained from the following equation (4). For example, a large concave distribution has a small load length ratio (Rmr(80)), and a large convex distribution has a large load length ratio (Rmr(80)).

The load length ratio (Rmr(80)) can be adjusted by the composition and content of the main curable resin composition described later.
According to the results of studies by the present inventors, in a cured resin layer that forms a phase separation structure by using fine particles in combination, as the amount of fine particles added increases, the formation area of the convex portion tends to become narrower. , it was also found that the area of the recess tends to widen. Therefore, in the present invention, the load length ratio (Rmr(80)) tends to decrease by containing fine particles.

(5) Protruding peak height (Spk)
The protruding peak height (Spk) is one of the surface roughness parameters obtained by measurement according to ISO25178. The height (Spk) of protruding peaks on the surface of the cured resin layer is preferably 70 nm or more, more preferably 100 nm or more, particularly preferably 150 nm or more, especially 200 nm or more.
By satisfying the above range, even if Sp of irregularities on the surface of the cured resin layer is small, the air leakage index is small and good film handleability can be ensured by the protrusions.
The protruding peak height (Spk) is not particularly limited, but is, for example, 500 nm or less.

(6) Ratio (Sp/Sa)
The ratio (Sp/Sa) between the maximum peak height (Sp) and the average surface roughness (Sa) of the cured resin layer surface is preferably 30 or less, more preferably 25 or less. By setting the ratio (Sp/Sa) to 30 or less, there is no large projection on the surface of the cured resin layer, the occurrence of pinholes and the like is suppressed, and thinning is facilitated. Although the ratio (Sp/Sa) is not particularly limited, it is, for example, 1 or more, and may be 3 or more.

[Polyester film]
(polyester)
The polyester in the polyester film of the present invention refers to the polyester that is the raw material for the polyester film, etc., refers to a polymer compound having continuous ester bonds in the main chain, and is a homopolyester or a copolymer polyester. may Specifically, a polyester obtained by subjecting a dicarboxylic acid component and a diol component to a polycondensation reaction can be mentioned.

Moreover, it is preferable to use a polyester containing more than 50 mol % of an aromatic dicarboxylic acid or an aliphatic dicarboxylic acid when the dicarboxylic acid component is taken as 100 mol %.

Examples of the dicarboxylic acid component include terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-diphenyldicarboxylic acid, Aromatic dicarboxylic acids such as 4,4'-diphenyletherdicarboxylic acid and 4,4'-diphenylsulfonedicarboxylic acid, such as adipic acid, suberic acid, sebacic acid, dimer acid, dodecanedioic acid, cyclohexanedicarboxylic acid and their esters Mention may be made of aliphatic dicarboxylic acids such as derivatives.

Examples of the diol component include ethylene glycol, 1,2-propanediol, 1,3-propanediol, neopentyl glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1 ,6-hexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-hexanedimethanol, diethylene glycol, triethylene glycol, polyalkylene glycol, 2,2-bis(4-hydroxyethoxy phenyl)propane, isosorbate and spiroglycol, and the like.

When the polyester is a homopolyester, it is preferably obtained by polycondensation of an aromatic dicarboxylic acid and an aliphatic diol. Preferred aromatic dicarboxylic acids include terephthalic acid and 2,6-naphthalenedicarboxylic acid, and preferred aliphatic diols include ethylene glycol, diethylene glycol and 1,4-cyclohexanedimethanol.
Typical polyesters include polyethylene terephthalate (PET), polyethylene-2,6-naphthalenedicarboxylate (PEN), etc., and polyethylene terephthalate is preferred.

On the other hand, the copolyester is preferably a polycondensation polymer of, for example, a dicarboxylic acid component and an aliphatic diol. As the dicarboxylic acid component, preferably one or two of isophthalic acid, phthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid and oxycarboxylic acid (e.g., p-oxybenzoic acid, etc.) species or more. As the aliphatic diol, one or more of ethylene glycol, diethylene glycol, propylene glycol, butanediol, 1,4-cyclohexanedimethanol, neopentyl glycol and the like are preferably used. More preferably, the copolyester contains terephthalic acid as the dicarboxylic acid component and ethylene glycol as the aliphatic diol.
When the above polyester is a copolymerized polyester, it is preferably a copolymer containing 30 mol % or less of the third component. The third component is a compound other than the compound that is the main component of the dicarboxylic acid component that constitutes the polyester (that is, the component that has the highest content) and the compound that is the main component of the diol component. For example, copolymerized polyethylene terephthalate are components other than terephthalic acid and ethylene glycol.
The copolyester may also contain a structural unit derived from a bifunctional compound other than the dicarboxylic acid component and the aliphatic diol. Structural units derived from bifunctional compounds other than dicarboxylic acid components and aliphatic diols are preferably 20 mol % or less, more preferably 10 mol % or less, relative to the total mol of all structural units constituting the polyester. Bifunctional compounds include various hydroxycarboxylic acids, aromatic diols, and the like.

The content of terephthalic acid in all dicarboxylic acid components constituting the present polyester film is preferably 50 mol % or more, more preferably 70 mol % or more, still more preferably 90 mol % or more.
In addition, the content of ethylene glycol in all diol components constituting the present polyester film is preferably 50 mol % or more, more preferably 70 mol % or more, still more preferably 90 mol % or more.
In addition, the upper limit of the content of terephthalic acid and ethylene glycol is 100 mol %.
As the above polyester, polyethylene terephthalate containing ethylene terephthalate units in an amount of 80 mol % or more, preferably 90 mol % or more, and polyethylene-2,6-naphthalate containing ethylene-2,6-naphthalate units are also preferable.
Further, the polyester may be a recycled polyester or a biomass-derived polyester.

<Polycondensation catalyst>
The polycondensation catalyst for polycondensing the above polyester is not particularly limited, and conventionally known compounds can be used, for example, titanium compounds, germanium compounds, antimony compounds, manganese compounds, aluminum compounds, magnesium compounds and calcium compounds. compounds and the like. Among these, at least one of an antimony compound and a titanium compound is preferred, and it is particularly preferred to use a polyester obtained using a titanium compound.
Therefore, the polyester film preferably contains at least one of an antimony compound and a titanium compound, and more preferably contains a titanium compound.
By using the titanium compound, the amount of the antimony compound used can be reduced as a result, so the risk of forming new protrusions due to precipitation of the antimony compound on the film surface is reduced, and high surface smoothness, especially , the present film having a small maximum peak height (Sp) on at least one side can be obtained.

It is preferable to use a titanium compound as a polycondensation catalyst for the polyester constituting the outermost layer of the polyester film (also referred to as "surface layer" or "surface layer", for example, the surface layer on which the cured resin layer is laminated). Therefore, the surface layer preferably contains a titanium compound.
The content of titanium element derived from the titanium compound in the outermost layer is preferably 3 ppm or more and 40 ppm or less, more preferably 4 ppm or more and 35 ppm or less, based on mass.
If it is within the above range, it is possible to reduce the amount of foreign matter caused by the catalyst without lowering the production efficiency of polyester.
From the viewpoint of productivity, it is preferable that the polyester constituting the intermediate layer (also referred to as the "base layer" or "intermediate layer" described later) does not use a titanium compound as a polycondensation catalyst.
From the same point of view, the content of the antimony compound in the surface layer of the present film is preferably 100 ppm or less on a mass basis.
For example, the surface layer (for example, surface layer A described later) preferably contains at least one of an antimony compound and a titanium compound, and the content of the antimony compound in the surface layer is 100 ppm or less. At this time, the surface layer may not contain an antimony compound. That is, the lower limit of the antimony compound content in the surface layer is preferably 0 ppm.

(Limiting viscosity of polyester (IV))
The intrinsic viscosity (IV) of the polyester constituting the polyester film is preferably 0.50 dL/g or more, more preferably 0.55 dL/g or more, and still more preferably 0.60 dL/g or more. Within this range, there is an advantage that the particles are highly dispersed due to an increase in shear stress during kneading. Moreover, the intrinsic viscosity (IV) of the polyester is, for example, 1.00 dL/g or less.

In addition, "intrinsic viscosity (IV) of polyester constituting the polyester film" means the intrinsic viscosity (IV) of these mixed resins when two or more polyesters having different intrinsic viscosities (IV) are used. shall be

From the above viewpoint, especially when the polyester film has a laminated structure, the intrinsic viscosity (IV) of the polyester constituting the surface layer, specifically the outermost layer of the present film (for example, the surface layer on which the cured resin layer is laminated) is preferably 0.50 dL/g or more, more preferably 0.55 dL/g or more, still more preferably 0.60 dL/g or more. Moreover, the intrinsic viscosity (IV) of the polyester is, for example, 1.00 dL/g or less.

<Particle>
Particles can also be incorporated into the present polyester film. By containing the particles, the polyester film is imparted with slipperiness and prevents the occurrence of scratches in each step, thereby improving handleability.
The type of particles to be contained in the present polyester film is not particularly limited as long as it is particles capable of imparting lubricity. Specific examples include silica, calcium carbonate, magnesium carbonate, barium carbonate, and calcium sulfate. , In addition to inorganic particles such as calcium phosphate, magnesium phosphate, kaolin, aluminum oxide, and titanium oxide, crosslinked polymers such as crosslinked silicone resin particles, crosslinked acrylic resin particles, crosslinked styrene-acrylic resin particles, and crosslinked polyester particles, calcium oxalate and organic particles such as ion exchange resins. Among these, organic particles, silica, aluminum oxide and the like are preferred, and silica and aluminum oxide are more preferred.

The shape of the particles to be used is not particularly limited either, and any of spherical, lumpy, rod-like, flattened and the like may be used.
Moreover, there are no particular restrictions on its hardness, specific gravity, color, and the like. Two or more kinds of these series of particles may be used in combination, if necessary.

The average particle size of the particles is preferable from the viewpoint of increasing the average surface roughness (Sa) of the cured resin layer surface or film surface and suppressing the maximum peak height (Sp), that is, from the viewpoint of improving handling properties and suppressing pinholes. is 0.05 to 0.8 μm, more preferably 0.1 to 0.6 μm, still more preferably 0.1 to 0.5 μm.
The average particle size of the particles can be obtained by measuring the diameters of 10 or more particles with a scanning electron microscope (SEM) and calculating the average value. At that time, in the case of non-spherical particles, the average value of the longest diameter and the shortest diameter can be measured as the diameter of each particle.

The method for adding particles to the present polyester film is not particularly limited, and conventionally known methods can be employed. For example, in the case of a multi-layered polyester film, it can be added at any stage in the production of the polyester constituting each layer, but it is preferably added after the esterification or transesterification reaction is completed.

In order to suppress the precipitation amount of the oligomer component, the film may be produced using a polyester having a low content of the oligomer component as a raw material. As a method for producing a polyester having a low content of oligomer components, various known methods can be used.
Further, the polyester film may have a structure of three or more layers, and the surface layer of the polyester film may be a layer using a polyester raw material with a low content of the oligomer component, thereby suppressing the precipitation amount of the oligomer component.
The polyester may also be obtained by subjecting the polyester to esterification or transesterification, followed by melt polycondensation under reduced pressure at a higher reaction temperature.

In addition to the particles described above, conventionally known ultraviolet absorbers, antioxidants, antistatic agents, heat stabilizers, lubricants, dyes, pigments, etc. can be added to the present polyester film as necessary. .

(Structure of polyester film)
The polyester film in the polyester roll of the present invention can employ either a single layer or a laminated structure (laminated film) having two or more layers, but preferably has a laminated structure of three or more layers. A laminated structure of three or more layers preferably has a surface layer, an intermediate layer (also referred to as a “base layer”), and a surface layer in this order. Either one of the surface layers is preferably provided so as to be in contact with the cured resin layer.

It is also preferable that the polyester film has a surface layer containing particles (also referred to as "surface layer C") on at least one surface. By adopting such a configuration, it is possible to improve the handleability of the film. The film may have the surface layer C on one side and the surface layer A on the other side. The surface layer A may or may not contain particles, but from the viewpoint of thinning the ceramic layer and suppressing pinholes, it substantially contains particles. preferably not.

In the polyester film, the surface layer opposite to the surface on which the cured resin layer is provided has a surface roughness (Sa) of preferably 9 nm or less, and 5 nm or less, from the viewpoint of thinning the ceramic layer and suppressing pinholes. More preferably, it is 4 nm or less. In addition, from the viewpoint of improving windability, the thickness is preferably 0.1 nm or more, more preferably 0.3 nm or more, and even more preferably 1 nm or more.
In the polyester film, the surface layer opposite to the surface on which the cured resin layer is provided has a maximum surface peak height (Sp) of 800 nm or less from the viewpoint of thinning the ceramic layer and suppressing pinholes. is preferred, more preferably 500 nm or less, and still more preferably 100 nm or less. On the other hand, the maximum peak height (Sp) is not particularly limited, but is preferably 5 nm or more, more preferably 10 nm or more, and still more preferably 20 nm or more from the viewpoint of film handleability.
The surface layer on the side opposite to the surface on which the cured resin layer having the above surface properties is provided may be a layer that substantially contains particles or a layer that does not substantially contain particles. good.

(Laminated structure of polyester film)
When the polyester film has a laminated structure with two or more layers, A/B/C composed of the base layer B, the surface layer A and the surface layer C and A/B composed of the base layer B and the surface layer A /A three-layer structure is preferred. That is, both surface layers may contain substantially no particles, both surface layers may contain substantially no particles, or one surface layer may contain substantially no particles. and the other surface layer may be substantially free of particles.

In the A/B/C and A/B/A configurations, the cured resin layer may be provided on either the surface layer C side or the surface layer A side, but is preferably provided on the surface layer C side. The cured resin layers provided on the surface layer C side and the surface layer A side are typically preferably formed so as to be in contact with the surface layer C and the surface layer A, respectively.
In addition, in the A/B/C and A/B/A configurations, the intermediate layer B may have a structure of four or more layers, such as a configuration of two or more layers. Further, the intermediate layer B and the surface layer A may have substantially the same composition, or the intermediate layer B and the surface layer C may have substantially the same composition.

The surface layer of the polyester film, which is provided with the cured resin layer and is in contact with the cured resin layer, may contain particles or may not contain particles substantially. From the viewpoint of suppressing pinholes, it is preferable to contain substantially no particles. In addition, the surface opposite to the surface on which the cured resin layer is provided may also contain particles, or may not substantially contain particles, but from the viewpoint of thinning and pinhole suppression Therefore, it is preferred not to contain particles. Moreover, it is preferable to contain particles from the viewpoint of the handleability of the film.
In addition, "substantially does not contain" means that it does not contain intentionally, specifically, the content of particles (particle concentration) is 200 ppm or less, more preferably 150 ppm or less, More preferably, it refers to 100 ppm or less.

The surface layer A preferably has an average surface roughness (Sa) and a maximum peak height (Sp) that are equal to or smaller than those of the surface layer C.

In the laminated structure of A/B/C, the surface layer C preferably has an average surface roughness (Sa) of 5 nm or more or a maximum peak height (Sp) of 220 nm or less. In this case, the average surface roughness (Sa) may be about 20 nm or less.
By adopting such a laminated structure, the surface layer C can be provided with a rough surface necessary for improving handleability, and the surface layer A can be provided with the smoothness necessary for imparting a thin ceramic layer. can be provided.
From the above viewpoints, the average surface roughness (Sa) of the surface layer A is preferably 0.1 nm or more and 5 nm or less, more preferably 0.2 nm or more and 4 nm or less. Also, the maximum peak height (Sp) is preferably 43 nm or less, more preferably 40 nm or less.

The surface layer C may contain particles having a substantially uniform average particle size with a narrow particle size distribution (having so-called monodispersity). For example, in the three-layer structure of A/B/C, the surface layer C can contain particles having a narrow particle size distribution and a substantially uniform average particle size.

As the particles having a substantially uniform average particle diameter with a narrow particle size distribution, in the particle size distribution of the particles, the particle diameter at which the cumulative number is 10% is D10, the particle diameter at which the cumulative number is 50% is D50, and the cumulative number When D90 is the particle diameter at which the ratio is 90%, (D90-D10)/D50 is preferably 0.4 or less, more preferably 0.2 or less.
The relational expression (D90-D10)/D50 indicates the variation in particle size based on D50. It has a small and sharp particle size distribution, and can impart extremely high smoothness to the present film while maintaining excellent handleability.
The particle size distribution of the particles is measured with a laser diffraction measuring device.

The average particle size of the particles contained in the surface layer C is preferably 0.05 to 0.8 μm, more preferably 0.1 to 0.6 μm, still more preferably 0.1 to 0.5 μm.

In addition, the polyester film contains the particles at a mass ratio of, for example, 500 ppm or more, preferably 500 to 2000 ppm, more preferably 500 ppm or more and 1500 ppm or less, among which 800 ppm or more and 1500 ppm or less. is more preferred. The mass ratio as used herein is the ratio of particles in each surface layer.

The surface layer C may contain the particles at a mass ratio of less than 2000 ppm, preferably 500 ppm or more and 1500 ppm or less, more preferably 800 ppm or more and 1200 ppm or less.

The base layer (intermediate layer) B preferably functions as the thickest main layer, and preferably contains particles at least at a lower concentration than the surface layer C in order to reduce costs. Also, the base layer (intermediate layer) B may be substantially free of particles.
The content of the particles in the base layer (intermediate layer) B may be, for example, 5000 ppm or less, preferably 1000 ppm or less, particularly preferably 500 ppm or less, based on mass.

As described above, the surface layer A is a layer different from the surface layer C. Specifically, in addition to a form in which the type of particles, average particle diameter and blending amount are different, a form in which the layer thickness is different can be exemplified. can be done.

Moreover, a configuration including a surface layer A and/or a surface layer C shown in (X) and (Y) below is particularly preferable. By adopting such a configuration, the present film can have excellent handleability and surface smoothness.

(X) Especially preferred embodiment 1
(1) In the configuration A/B/C, the surface layer C contains particles and a titanium compound, and the surface layer A does not substantially contain particles. (2) In (1), the surface layer C contains at least (3) In any one of (1) to (2) above, the surface layer C contains an antimony compound and/or a titanium compound, and the antimony A mode in which the content of the compound is 100 ppm or less on a mass basis (4) In any of the above (1) to (3), the particles have a particle diameter at which the cumulative number is 10%, and the cumulative number is 50%. (D90-D10)/D50 is 0.4 or less, where D50 is the particle diameter at which the cumulative number is 90%, and D90 is the particle diameter at which the cumulative number is 90%. , silica particles and aluminum oxide

In the above (X), each of the surface layer A and the surface layer C uses a polyester polycondensed with a titanium compound as a catalyst, so that foreign matter caused by the catalyst can be reduced, and high surface smoothness can be provided. be able to. In (X) above, the cured resin layer is preferably formed on the surface layer (A) side.

(Y) Especially preferred embodiment 2
(1) In the A/B/A configuration, the surface layer A contains substantially no particles (2) In (1), the surface layer A contains an antimony compound and/or a titanium compound, (3) In (1) or (2) above, the intrinsic viscosity (IV) of the polyester constituting the surface layer A is 0.50 dL/g or more, preferably 0. 0.55 dL/g or more, more preferably 0.60 or more

In the above (Y), the surface layer A takes a form in which substantially no particles are contained, and a polyester film having high surface smoothness, especially a small maximum peak height (Sp) on at least one side can be obtained.

(Method for producing polyester film)
Hereinafter, production examples of the polyester film in the polyester roll of the present invention will be described in detail, but the invention is not limited to the following production examples.
For example, when producing a biaxially stretched film, the dried pellets of the polyester raw material described above are extruded as a molten sheet from a die using a melt extruder such as an extruder, and then cooled and solidified with a cooling roll such as a rotating cooling drum. A method of obtaining an unstretched sheet is preferred. Here, the cooling is preferably carried out, for example, to a temperature not higher than the glass transition point of the polymer to obtain a substantially amorphous non-oriented sheet (unstretched sheet). Further, in order to improve the flatness of the sheet, it is preferable to increase the adhesion between the sheet and the cooling roll, and the electrostatic application adhesion method and/or the liquid coating adhesion method are preferably employed.

The resulting unstretched sheet is then biaxially stretched. In that case, first, the unstretched sheet is stretched in one direction by a roll or tenter type stretching machine. The stretching temperature is usually 25 to 120° C., preferably 35 to 100° C., and the stretching ratio is usually 2.5 to 7 times, preferably 2.8 to 6 times.

Next, the film is stretched in a direction perpendicular to the stretching direction of the first stage. In this case, the stretching temperature is usually 50 to 140° C., and the stretching ratio is usually 3.0 to 7 times, preferably 4.5 times or more. , more preferably 4.5 to 5.0 times.

Subsequently, heat treatment is performed at a temperature of 180 to 220° C. under tension or under relaxation of 30% or less to obtain a biaxially stretched film. This heat treatment is also called a heat setting process. The heat treatment may be performed in two or more steps with different temperatures.
Also, cooling may be performed in a cooling zone after the heat treatment. The cooling temperature is preferably higher than the glass transition temperature (Tg) of the polyester resin constituting the film, and more specifically, preferably in the range of 100 to 160°C. This cooling may be performed in two or more steps with different temperatures.
In the above stretching, a method of stretching in one direction in two or more stages can also be employed. In that case, it is preferable to carry out so that the stretching ratios in the two directions finally fall within the above ranges.
A simultaneous biaxial stretching method can also be employed for the production of the present polyester film.

<< Cured resin layer >>
This laminated polyester film is provided with a cured resin layer formed from a cured resin composition on at least one side of the polyester film.
As described above, the main cured resin layer is formed from a cured resin composition (hereinafter also referred to as "the present composition") and has an uneven structure.

<Uneven structure>
The concave-convex structure of the cured resin layer is a fine shape formed by phase separation. The unevenness caused by phase separation is caused by phase separation in the process of application, stretching, drying, curing, heat treatment, etc., of resins having different compatibility, thereby forming an uneven structure on the surface. More specifically, phase separation forms recesses or protrusions to form an uneven structure on the surface.
The structure can be confirmed by means of various surface analysis techniques, such as an atomic force microscope (scanning probe microscope).

Here, in the present invention, "resin" refers to a main component involved in film formation. More specifically, the "resin" includes compound (A), compound (B), compound (C), etc., which will be described later.

<Cured resin composition>
This cured resin composition is required to contain the following compounds (A), (B) and (D).
(A) release agent (B) cross-linking agent (D) fine particles

The total content of compounds (A) and (B) contained in the present composition is preferably 30% by mass or more as non-volatile components. More preferably 40% by mass or more, still more preferably 50% by mass or more, and even more preferably 55% by mass or more. If the total content is in such a range, the effect of phase separation is sufficiently exhibited, and it becomes easy to obtain a desired fine uneven structure. The total content of the compounds (A) and (B) is not particularly limited in terms of the upper limit, but from the viewpoint of containing a certain amount of (D) fine particles and (C) a binder described later, for example, 97% by mass or less, It is preferably 90% by mass or less, more preferably 80% by mass or less, and even more preferably 70% by mass or less.

(((Compound (A))))
The present composition contains (A) a release agent ((compound (A)). The release agent is not particularly limited, and conventionally known release agents can be used. For example, wax, Examples include long-chain alkyl group-containing compounds, fluorine compounds, silicone compounds, etc. Among them, at least one of wax and long-chain alkyl group-containing compounds is preferable, and wax is more preferable. Compound (A) may be used singly or in combination of two or more.

As described above, the uneven structure of the present resin layer is formed by phase separation of resins having different compatibility. The water-repellent and/or oil-repellent effect can effectively develop a fine concave-convex structure. Although the mechanism by which the unevenness is formed by the water- and/or oil-repellent effect is not clear, the water- and/or oil-repellent effect repels other resins, and the repelled resin forms protrusions. It is estimated that fine unevenness is formed more effectively.

(wax)
Examples of the wax include natural wax, synthetic wax and modified wax.
Natural waxes are vegetable waxes, animal waxes, mineral waxes and petroleum waxes.
Vegetable waxes include candelilla wax, carnauba wax, rice wax, Japan wax and jojoba oil.
Animal waxes include beeswax, lanolin and whale wax.
Mineral waxes include montan wax, ozokerite and ceresin.
Petroleum waxes include paraffin wax, microcrystalline wax and petrolatum.
Synthetic waxes include synthetic hydrocarbons, modified waxes, hydrogenated waxes, fatty acids, acid amides, amines, imides, ester waxes and ketones.

Synthetic waxes include, for example, Fischer-Tropsch wax (also known as Sasol wax) and polyethylene wax. In addition, the following polymers that are low molecular weight polymers (specifically, polymers with a number average molecular weight of 500 to 20000): polypropylene, ethylene-acrylic acid copolymer, polyethylene glycol, polypropylene glycol and polyethylene glycol Polypropylene glycol block or graft conjugates and the like can be mentioned.

Modified waxes include, for example, montan wax derivatives, paraffin wax derivatives and microcrystalline wax derivatives. The derivative here is a compound obtained by purification, oxidation, esterification, saponification, or a combination thereof. Hydrogenated waxes may include hydrogenated castor oil and hydrogenated castor oil derivatives.

Among them, synthetic waxes are preferable as the release agent from the viewpoint of excellent unevenness-forming performance due to phase separation, polyethylene waxes are more preferable, and oxidized polyethylene waxes are even more preferable.
When the present composition is diluted with a solvent such as water to form a coating liquid, the wax may be dispersed with a surfactant or the like to form a wax emulsion and blended into the coating liquid.

The number average molecular weight of the synthetic wax is generally in the range of 500 to 30,000, preferably 1,000 to 15,000, and more preferably 2,000 to 8,000, from the viewpoints of unevenness-forming performance due to phase separation and handleability. In addition, a number average molecular weight is a value of polystyrene conversion measured using a gel permeation chromatography (GPC).

Considering that the cured resin layer is heated for cross-linking when forming the cured resin layer, the melting point or softening point of the wax is preferably 80° C. or higher, more preferably 110° C. or higher. On the other hand, the temperature is preferably 200° C. or lower, more preferably 170° C. or lower, and still more preferably 150° C. or lower from the viewpoint of controlling the phase separation performance after the heat treatment. In particular, when the process of heat treatment triggers phase separation, although it is not clear, it is assumed that the wax melts and the melted wax repels other resins, thereby forming protrusions.
The melting point of wax can be measured with a differential scanning calorimeter (DSC).

(Long-chain alkyl group-containing compound)
A long-chain alkyl group-containing compound is a compound having a linear or branched alkyl group having 6 or more carbon atoms, preferably 8 or more carbon atoms, more preferably 12 or more carbon atoms.
Examples of the alkyl group include alkyl groups having about 6 to 30 carbon atoms such as hexyl group, octyl group, decyl group, lauryl group, octadecyl group and behenyl group. Examples of compounds having an alkyl group include various long-chain alkyl group-containing polymer compounds, long-chain alkyl group-containing amine compounds, long-chain alkyl group-containing ether compounds, long-chain alkyl group-containing quaternary ammonium salts, and the like. . Considering heat resistance, it is preferable to use a polymer compound, and a polymer compound having a long-chain alkyl group in the side chain from the viewpoint that it is possible to effectively obtain unevenness-forming performance due to moderate phase separation with a small content. is more preferable.

A polymer compound having a long-chain alkyl group in a side chain can be obtained by reacting a polymer having a reactive group with a compound having an alkyl group capable of reacting with the reactive group. Examples of the reactive groups include hydroxyl groups, amino groups, carboxyl groups, acid anhydrides, and the like. Examples of compounds having these reactive groups include polyvinyl alcohol, polyethyleneimine, polyethyleneamine, reactive group-containing polyester resins, and reactive group-containing poly(meth)acrylic resins. Among these, polyvinyl alcohol is preferable in consideration of ease of handling. The degree of polymerization of the polyvinyl alcohol used is not particularly limited, but is usually 100 or more, preferably in the range of 300-40,000. The degree of saponification of polyvinyl alcohol is not particularly limited, but is usually 70 mol% or more, preferably in the range of 70 to 99.9 mol%, more preferably 80 to 97 mol%, further preferably 86 to 99.9 mol%. 95 mol % is used.

The compound having an alkyl group capable of reacting with the reactive group includes, for example, hexyl isocyanate, octyl isocyanate, decyl isocyanate, lauryl isocyanate, octadecyl isocyanate, behenyl isocyanate and other long-chain alkyl group-containing isocyanates, hexanoyl chloride, octanoyl long-chain alkyl group-containing acid chlorides such as chloride, decanoyl chloride, lauroyl chloride, octadecanoyl chloride and behenoyl chloride; long-chain alkyl group-containing amines; long-chain alkyl group-containing alcohols; Among these, long-chain alkyl group-containing isocyanates are preferred, and octadecyl isocyanate is particularly preferred, in view of ease of handling.

Polymer compounds having long-chain alkyl groups in side chains can also be obtained by polymerizing long-chain alkyl (meth)acrylates or by copolymerizing long-chain alkyl (meth)acrylates with other vinyl group-containing monomers. . Examples of long-chain alkyl (meth)acrylates include hexyl (meth)acrylate, octyl (meth)acrylate, decyl (meth)acrylate, lauryl (meth)acrylate, octadecyl (meth)acrylate, and behenyl (meth)acrylate. .

(Fluorine compound)
A fluorine compound is a compound containing a fluorine atom in the compound. Organic fluorine compounds are preferably used in terms of coating appearance by in-line coating, and examples thereof include perfluoroalkyl group-containing compounds, polymers of olefin compounds containing fluorine atoms, and aromatic fluorine compounds such as fluorobenzene. A compound having a perfluoroalkyl group is preferable from the viewpoint that a small content can effectively provide unevenness-forming performance due to moderate phase separation. Furthermore, compounds containing long-chain alkyl compounds as described above can also be used as fluorine compounds.

Compounds having a perfluoroalkyl group include, for example, perfluoroalkyl (meth)acrylate, perfluoroalkylmethyl (meth)acrylate, 2-perfluoroalkylethyl (meth)acrylate, 3-perfluoroalkylpropyl (meth)acrylate, Perfluoroalkyl group-containing (meth)acrylates such as 3-perfluoroalkyl-1-methylpropyl (meth)acrylate and 3-perfluoroalkyl-2-propenyl (meth)acrylate, polymers thereof, perfluoroalkylmethyl vinyl ether, Perfluoroalkyl group-containing vinyl ethers such as 2-perfluoroalkylethyl vinyl ether, 3-perfluoropropyl vinyl ether, 3-perfluoroalkyl-1-methylpropyl vinyl ether, 3-perfluoroalkyl-2-propenyl vinyl ether, polymers thereof, etc. is mentioned. Considering heat resistance, it is preferably a polymer. The polymer may be a single compound or a polymer of multiple compounds. In addition, the perfluoroalkyl group preferably has 3 to 11 carbon atoms from the viewpoint that it is possible to effectively obtain unevenness-forming performance due to moderate phase separation with a small content. Furthermore, it may be a polymer with a compound containing a long-chain alkyl compound as described above, and a polymer with vinyl chloride is also preferably used from the viewpoint of adhesion to the polyester film that is the base material. .

(silicone compound)
A silicone compound is a compound having a silicone structure in the molecule, and includes silicone emulsion, acrylic-grafted silicone, silicone-grafted acrylic, amino-modified silicone, perfluoroalkyl-modified silicone, alkyl-modified silicone, and the like. Considering heat resistance, it is preferable to contain a curable silicone resin.
As the type of curable silicone resin, any curing reaction type such as addition type, condensation type, ultraviolet curing type, electron beam curing type, etc. can be used.

The content of compound (A) in the present composition is preferably 5 to 90% by mass, more preferably 15 to 85% by mass, and still more preferably 20 to 60% as a proportion of the total nonvolatile components in the present composition. % by weight, more preferably in the range of 25 to 45% by weight. By setting the content to 5% by mass or more, it is possible to sufficiently form an uneven structure due to phase separation. In addition, by setting the content to 90% by mass or less, it is possible to secure the content of other resins, and it is possible to appropriately adjust the unevenness forming performance due to phase separation.

(((Compound (B))))
The composition contains (B) a cross-linking agent (compound (B)). The compound (B) can also contribute to the formation of a fine uneven structure by phase separation, and can improve the coatability when the present composition is used as a coating liquid.

The cross-linking agent selected as the compound (B) is not particularly limited, and conventionally known cross-linking agents can be used. The composition can be easily cured by using a cross-linking agent. Examples of cross-linking agents include melamine compounds, oxazoline compounds, epoxy compounds, carbodiimide compounds, isocyanate compounds, and silane coupling compounds. Among them, at least one of a melamine compound and an oxazoline compound is preferably used as the cross-linking agent, and a melamine compound is more preferable, from the viewpoint of easiness of adjusting the unevenness forming performance by phase separation. In the present composition, the cross-linking agent may be used singly or in combination of two or more.

(melamine compound)
A melamine compound is a compound having a melamine skeleton in the compound, and examples thereof include alkylolated melamine derivatives, compounds obtained by reacting alkylolated melamine derivatives with alcohol to partially or completely etherify them, and mixtures thereof. can be used.
Examples of alkylolation include methylolation, ethylolation, isopropylolation, n-butyrolation, and isobutyrolation. Among these, methylolation is preferable from the viewpoint of reactivity.
As the alcohol used for etherification, methanol, ethanol, isopropanol, n-butanol, isobutanol and the like are preferably used, and among these, methanol is more preferable.
Moreover, the melamine compound may be either a monomer or a polymer of dimers or higher, or a mixture thereof. Further, melamine may be partially co-condensed with urea or the like, and a catalyst may be further used in the present composition in order to increase the reactivity of the melamine compound.

(oxazoline compound)
An oxazoline compound is a compound having an oxazoline group in its molecule, and a polymer containing an oxazoline group is particularly preferred, and can be prepared by polymerization of an addition polymerizable oxazoline group-containing monomer alone or with another monomer. Addition polymerizable oxazoline group-containing monomers include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-ethyl-2-oxazoline and the like can be mentioned, and one or a mixture of two or more thereof can be used. Among these, 2-isopropenyl-2-oxazoline is suitable because it is easily available industrially. Other monomers are not limited as long as they are copolymerizable with addition-polymerizable oxazoline group-containing monomers. , n-butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group and cyclohexyl group); acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, Unsaturated carboxylic acids such as styrenesulfonic acid and salts thereof (sodium salts, potassium salts, ammonium salts, tertiary amine salts, etc.); Unsaturated nitriles such as acrylonitrile and methacrylonitrile; (meth)acrylamide, N-alkyl (Meth)acrylamide and N,N-dialkyl(meth)acrylamide (as alkyl groups, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, 2-ethylhexyl vinyl esters such as vinyl acetate and vinyl propionate; vinyl ethers such as methyl vinyl ether and ethyl vinyl ether; α-olefins such as ethylene and propylene; vinyl chloride and vinylidene chloride halogen-containing α,β-unsaturated monomers such as; α,β-unsaturated aromatic monomers such as styrene and α-methylstyrene; be able to.
Also, the oxazoline compound may have a polyalkylene oxide chain such as a polyethylene oxide chain, and for example, a (meth)acrylate having a polyalkylene oxide chain may be used as another monomer.
From the viewpoint of improving the adhesion of the resin layer to the polyester film, the oxazoline group content of the oxazoline compound is preferably in the range of 0.5 to 10 mmol/g, more preferably 1 to 9 mmol/g, and still more preferably 3 to 8 mmol/g. is.

(epoxy compound)
Epoxy compounds are compounds having an epoxy group in the molecule, and include condensates with hydroxyl groups and amino groups such as epichlorohydrin, ethylene glycol, polyethylene glycol, glycerin, polyglycerin and bisphenol A, and polyepoxy compounds. , diepoxy compounds, monoepoxy compounds and glycidylamine compounds.
Examples of polyepoxy compounds include sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, triglycidyl tris(2-hydroxyethyl) isocyanate, glycerol polyglycidyl ether and trimethylolpropane poly glycidyl ether and the like.
Examples of diepoxy compounds include neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, resorcin diglycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, and polypropylene glycol diglycidyl ether. Ether and polytetramethylene glycol diglycidyl ether and the like.
Examples of monoepoxy compounds include allyl glycidyl ether, 2-ethylhexyl glycidyl ether and phenyl glycidyl ether, and examples of glycidylamine compounds include N,N,N',N'-tetraglycidyl-m-xylylenediamine, 1,3-bis (N,N-diglycidylamino)cyclohexane and the like. From the viewpoint of improving the adhesion of the resin layer to the polyester film, a polyether-based epoxy compound is preferred.
As for the amount of epoxy groups, a polyepoxy compound having a polyfunctionality of 3 or more is preferable to a bifunctional one.

(carbodiimide compound)
A carbodiimide compound is a compound having a carbodiimide structure, and is a compound having one or more carbodiimide structures in the molecule. More preferred are polycarbodiimide compounds having one or more carbodiimide structures.

A carbodiimide compound can be synthesized by a conventionally known technique, and generally a condensation reaction of a diisocyanate compound is used. The diisocyanate compound is not particularly limited, and both aromatic and aliphatic compounds can be used. Specifically, tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, phenylene diisocyanate, naphthalene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, cyclohexane diisocyanate, methylcyclohexane diisocyanate, isophorone diisocyanate, dicyclohexyl diisocyanate and dicyclohexylmethane 4,4'-diisocyanate.

The content of the carbodiimide group contained in the carbodiimide compound is usually 100 to 1000, preferably 250 to 800, more preferably 300 to 300, in terms of carbodiimide equivalent (weight [g] of the carbodiimide compound to give 1 mol of carbodiimide group). 700 range. Durability of a resin layer improves by using it in the said range.

Furthermore, in order to improve the water solubility and water dispersibility of the polycarbodiimide compound, a surfactant may be added, polyalkylene oxide, quaternary ammonium salt of dialkylamino alcohol, and Hydrophilic monomers such as hydroxyalkylsulfonates may be added and used.

(isocyanate compound)
An isocyanate compound is a compound having an isocyanate derivative structure represented by isocyanate or blocked isocyanate. Examples of isocyanates include aromatic isocyanates such as tolylene diisocyanate, xylylene diisocyanate, methylene diphenyl diisocyanate, phenylene diisocyanate and naphthalene diisocyanate; aliphatic isocyanates such as methylene diisocyanate, propylene diisocyanate, lysine diisocyanate, trimethylhexamethylene diisocyanate and hexamethylene diisocyanate; Alicyclic isocyanate etc. are illustrated.
Polymers and derivatives of these isocyanates such as buret products, isocyanurate products, uretdione products and carbodiimide modified products are also included. These may be used alone or in combination of multiple types. Among the above isocyanates, aliphatic isocyanates or alicyclic isocyanates are more preferable than aromatic isocyanates in order to avoid yellowing due to ultraviolet rays.

When used in the form of blocked isocyanate, blocking agents include, for example, bisulfites; phenolic compounds such as phenol, cresol and ethylphenol; alcoholic compounds such as propylene glycol monomethyl ether, ethylene glycol, benzyl alcohol, methanol and ethanol. Compounds; active methylene compounds such as methyl isobutanoylacetate, dimethyl malonate, diethyl malonate, methyl acetoacetate, ethyl acetoacetate and acetylacetone; mercaptan compounds such as butyl mercaptan and dodecyl mercaptan; ε-caprolactam, δ-valerolactam and the like amine compounds such as diphenylaniline, aniline and ethyleneimine; acid amide compounds of acetanilide and acetic acid amide; These may be used alone or in combination of two or more.

Also, the isocyanate compound may be used alone, or may be used as a mixture or combination with various polymers. From the viewpoint of improving the dispersibility and crosslinkability of the isocyanate compound, it is preferable to use a mixture or combination with a polyester resin or a polyurethane resin.

(Silane coupling compound)
A silane coupling compound is an organosilicon compound having an organic functional group and a hydrolyzable group such as an alkoxy group in one molecule. For example 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, 2-(3,4-epoxy Epoxy group-containing compounds such as cyclohexyl)ethyltrimethoxysilane; Vinyl group-containing compounds such as vinyltrimethoxysilane and vinyltriethoxysilane; Styryl group-containing compounds such as p-styryltrimethoxysilane and p-styryltriethoxysilane; - (meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, 3-(meth)acryloxypropylmethyldimethoxysilane, 3-(meth)acryloxypropylmethyldiethoxysilane, etc. ( meth) acrylic group-containing compounds; 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3 -aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldiethoxysilane, 3-triethoxysilyl-N- Amino group-containing compounds such as (1,3-dimethylbutylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane; tris(trimethoxysilylpropyl)isocyanate Nurate, isocyanurate group-containing compounds such as tris(triethoxysilylpropyl) isocyanurate; 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropylmethyldiethoxy A mercapto group-containing compound such as silane can be used.

The content of the cross-linking agent in the composition is preferably 3 to 50% by mass, more preferably 8 to 45% by mass, and still more preferably 10 to 40% by mass as a proportion of the total nonvolatile components in the composition. , and more preferably in the range of 15 to 35% by mass. By setting the content within the above range, it becomes easier to form an uneven structure having a predetermined surface roughness. In addition, it becomes easy to appropriately apply the curable resin composition, curability, and the like.

(Compound (C))
The composition may contain (C) a binder resin (compound (C)). The compound (C) can also contribute to the formation of a fine uneven structure by phase separation, and can improve the coatability when the present composition is used as a coating liquid.

The binder resin selected as the compound (C) is measured by gel permeation chromatography (GPC) according to the "High molecular compound safety evaluation flow scheme" (November 1985, sponsored by the Chemical Substances Council). It is defined as a polymer compound having a number average molecular weight (Mn) of 1000 or more and having film-forming properties.
Such a binder resin is not particularly limited, and conventionally known binder resins can be used. For example, (meth)acrylic resin, polyvinyl alcohol, polyester resin, ion conductive polymer compound, polyurethane resin and the like can be mentioned. Among them, it is preferable to use at least one of a (meth)acrylic resin and polyvinyl alcohol, and a (meth)acrylic resin is more preferable, from the viewpoint of maintaining the unevenness forming performance by phase separation and film formation. In this composition, the binder resin may be used singly or in combination of two or more.

((meth)acrylic resin)
A (meth)acrylic resin is a polymer composed of polymerizable monomers including acrylic and methacrylic monomers. These may be homopolymers, copolymers, or copolymers with polymerizable monomers other than acrylic and methacrylic monomers.
A (meth)acrylic polymer is a polymer having structural units derived from (meth)acrylic acid or (meth)acrylic acid alkyl esters. The (meth)acrylic polymer may be at least one polymer selected from (meth)acrylic acid and (meth)acrylic acid alkyl ester, or at least one selected from these and monomers other than these , such as styrene or styrene derivatives, monomers containing hydroxyl groups, and the like.
Copolymers of these polymers with other polymers (eg, polyester, polyurethane, etc.) are also included. Examples include block copolymers and graft copolymers. That is, the (meth)acrylic resin may be a (meth)acryl-modified polyester resin or a (meth)acryl-modified polyurethane resin.
Alternatively, a polymer obtained by polymerizing a polymerizable monomer in a polyester solution or a polyester dispersion (sometimes a mixture of polymers) is also included. Similarly, polymers obtained by polymerizing polymerizable monomers in polyurethane solutions and polyurethane dispersions (mixtures of polymers in some cases) are also included. Similarly, other polymer solutions or polymers obtained by polymerizing polymerizable monomers in dispersions (polymer mixtures in some cases) are also included, and these are also referred to herein as (meth)acrylic-modified polyester resins and , (meth)acrylic-modified polyurethane resin. The polyester and polyurethane used in the (meth)acrylic resin can be appropriately selected and used from those exemplified as the polyester and polyurethane used in the binder resin described later.
In addition, the (meth)acrylic resin may contain a hydroxy group and an amino group in order to further improve adhesion to the polyester film.

The polymerizable monomer is not particularly limited, but particularly representative compounds include various carboxyl group-containing monomers such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, fumaric acid, maleic acid, and citraconic acid. , and salts thereof; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, monobutyl hydroxy fumarate, monobutyl hydroxy itaconate, etc. Various hydroxyl group-containing Monomers; various alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, lauryl (meth)acrylate; (meth)acrylamide , diacetone acrylamide, or (meth)acrylonitrile; hydroxyl group-containing nitrogen-containing monomers such as N-methylol (meth)acrylamide; styrene, α-methylstyrene, divinylbenzene, vinyltoluene, etc. Various styrene derivatives; various vinyl esters such as vinyl propionate; various silicon-containing polymerizable monomers such as γ-methacryloxypropyltrimethoxysilane and vinyltrimethoxysilane; phosphorus-containing vinyl monomers; various vinyl halides such as vinylidene chloride; and various conjugated dienes such as butadiene.

Among the above (meth)acrylic resins, polymers obtained by polymerizing polymerizable monomers containing acrylic and methacrylic monomers are preferable, and more preferably the polymerizable monomers contain alkyl (meth)acrylic acid esters. preferable.
The present composition containing a (meth)acrylic resin is preferably diluted with a solvent to form a coating liquid as described later, and the solvent preferably contains water as the main solvent (50% by mass or more). That is, the polymerizable monomer preferably has a hydrophilic group such as a hydroxyl group or a carboxyl group from the viewpoint of facilitating dissolution or dispersion when the coating liquid is an aqueous system. In addition, from the viewpoint of obtaining an uneven structure effectively by phase separation, it is preferable to have a hydrophilic group such as a hydroxyl group or a carboxyl group.
Therefore, the acrylic resin is also preferably a polymer obtained by polymerizing an alkyl (meth)acrylate and a polymerizable monomer containing a hydrophilic group-containing monomer such as a hydroxyl group-containing monomer and a carboxyl group-containing monomer.
The acrylic resin may also be an emulsion polymer obtained by polymerizing a polymerizable monomer in the presence of a surfactant, for example.

(polyvinyl alcohol)
Polyvinyl alcohol is a compound having a polyvinyl alcohol moiety. For example, conventionally known polyvinyl alcohols including partially acetalized or butyralized modified compounds can be used. Although the degree of polymerization of polyvinyl alcohol is not particularly limited, it is usually 100 or more, preferably in the range of 300 to 40,000. When the degree of polymerization is 100 or more, it becomes easy to improve the water resistance of the resin layer. The degree of saponification of polyvinyl alcohol is not particularly limited, but is usually 70 mol% or more, preferably in the range of 70 to 99.9 mol%, more preferably 80 to 97 mol%, further preferably 86 to 99.9 mol%. A saponified polyvinyl acetate of 95 mol % is used in practice.

(polyester resin)
Examples of polyester resins include those composed of polyvalent carboxylic acids and polyvalent hydroxy compounds as shown below as main constituents.
That is, polyvalent carboxylic acids include terephthalic acid, isophthalic acid, orthophthalic acid, phthalic acid, 4,4′-diphenyldicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6- Naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 2-potassium sulfoterephthalic acid, 5-sodium sulfoisophthalic 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 salts and ester-forming derivatives thereof can be used. Polyvalent hydroxy compounds include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 2-methyl-1,5-pentanediol, neo Pentyl 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, dimethylol Propionic acid, glycerin, trimethylolpropane, sodium dimethylolethylsulfonate, potassium dimethylolpropionate, and the like can be used. One or more of these compounds may be appropriately selected, and a polyester resin may be synthesized by a conventional polycondensation reaction.

In addition, as a part of the polyvalent carboxylic acid, a product obtained by copolymerizing sulfoisophthalic acids such as 5-sodium sulfoisophthalic acid to introduce a sulfonic acid group into the polyester skeleton and neutralizing to make it hydrophilic is preferable. Used. The amount to be copolymerized is generally 1 to 13 mol %, preferably 3 to 10 mol %, more preferably 5 to 9 mol %, based on the total polycarboxylic acid. By introducing an appropriate amount of sulfonic acid groups, the hydrophilicity of the resin can be enhanced and the uneven structure can be easily formed. Furthermore, water dispersion stability can be improved.

(Ion-conductive polymer compound)
The ion-conductive polymer compound is a polymer compound containing an ion-conductive functional group, and examples thereof include polymer compounds such as ammonium group-containing compounds, polyether compounds, sulfonic acid compounds, and betaine compounds. Among these, an ammonium group-containing compound is particularly preferable from the viewpoint of having high polarity and effectively forming irregularities.

The ammonium group-containing compound refers to a compound having an ammonium group in its molecule, and is preferably a polymer compound having an ammonium group. For example, a polymer containing as a component a monomer having an ammonium group and an unsaturated double bond can be used.

Specific examples of such polymers include polymers having, as repeating units, constituent elements represented by the following formula (1). These homopolymers and copolymers, and a plurality of other components may be copolymerized.

In formula (1) above, R ¹ and R ² are each independently a hydrogen atom, an alkyl group, a phenyl group, or the like, and these alkyl groups and phenyl groups may be substituted with groups shown below. Substitutable groups are, for example, hydroxyl groups, amide groups, ester groups, alkoxy groups, phenoxy groups, naphthoxy groups, thioalkoxy groups, thiophenoxy groups, cycloalkyl groups, trialkylammoniumalkyl groups, cyano groups, halogens, and the like. be. Also, R ¹ and R ² may be chemically bonded, for example, —(CH ₂ ) _m — (m=an integer from 2 to 5), —CH(CH ₃ )CH(CH ₃ )—, -CH=CH-CH=CH-, -CH=CH-CH=N-, -CH=CH-N=C-, -CH ₂ OCH ₂ -, -(CH ₂ ) ₂ O(CH ₂ ) ₂ - etc. can be mentioned.

X- in the above formula (1) can be appropriately selected within a range that does not impair the gist of the present invention. Examples include halogen ions, sulfonates, phosphates, nitrates, alkylsulfonates, carboxylates and the like.

Among the above polymers, that is, polymers containing monomers having an ammonium group and an unsaturated double bond as components, from the viewpoint of enhancing film-forming properties and obtaining stable coatings, copolymerization with other monomers You may have
Other monomers include, for example, alkyl acrylates such as methyl acrylate, ethyl acrylate, propyl acrylate and butyl acrylate; alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, propyl methacrylate and butyl methacrylate; Acrylamides such as n-methylolacrylamide may be mentioned.

Further, from the viewpoint of increasing polarity and effectively forming unevenness, a homopolymer having a repeating unit of the constituent element represented by the above formula (1) is preferable.

The number average molecular weight of the ammonium group-containing compound is preferably 1,000 to 500,000, more preferably 2,000 to 350,000, still more preferably 5,000 to 200,000 or less. By setting the molecular weight to 1000 or more, it is possible to prevent the strength of the coating film from being weakened, and it becomes easy to improve the heat resistance stability. In addition, by setting the molecular weight to 500,000 or less, it is possible to prevent the viscosity of the coating liquid from increasing, thereby making it easier to improve the handling and coating properties.

(polyurethane resin)
A polyurethane resin is a polymer compound having a urethane bond in its molecule, and is preferably water-dispersible or water-soluble. In the present invention, it may be used alone or in combination of two or more.

In order to impart water dispersibility or water solubility, it is common and preferred to introduce a hydrophilic group such as a hydroxyl group, a carboxyl group, a sulfonic acid group, a sulfonyl group, a phosphoric acid group or an ether group into the polyurethane resin. Among the hydrophilic groups, a carboxyl group or a sulfonic acid group is particularly preferable from the viewpoint of adhesion between the resin layer and the polyester film.

One of the methods for preparing polyurethane resins is by reacting a hydroxyl group-containing compound with isocyanate. As the hydroxyl group-containing compound used as a raw material, polyols are preferably used, and examples thereof include polyether polyols, polyester polyols, polycarbonate polyols, polyolefin polyols, and acrylic polyols. These compounds may be used alone or in combination.

Polyether polyols include polyethylene glycol, polypropylene glycol, polyethylene propylene glycol, polytetramethylene ether glycol, polyhexamethylene ether glycol and the like.

Polyester polyols include those obtained from polyhydric carboxylic acids or their acid anhydrides and polyhydric alcohols. Examples of polycarboxylic acids include malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, sebacic acid, fumaric acid, maleic acid, terephthalic acid, and isophthalic acid. Polyhydric alcohols include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 2-methyl-1,3-propanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 2-methyl-2,4-pentanediol , 2-methyl-2-propyl-1,3-propanediol, 1,8-octanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2 ,5-dimethyl-2,5-hexanediol, 1,9-nonanediol, 2-methyl-1,8-octanediol, 2-butyl-2-ethyl-1,3-propanediol, 2-butyl-2 -hexyl-1,3-propanediol, cyclohexanediol, bishydroxymethylcyclohexane, dimethanolbenzene, bishydroxyethoxybenzene, alkyldialkanolamine, lactonediol, etc.).

Polycarbonate-based polyols include polycarbonate diols obtained by a dealcoholization reaction from polyhydric alcohols and dimethyl carbonate, diethyl carbonate, diphenyl carbonate, ethylene carbonate, etc., such as poly(1,6-hexylene) carbonate, poly(3 -methyl-1,5-pentylene)carbonate and the like.
Among the above, polyester polyols are preferred.

Polyisocyanate compounds used to obtain polyurethane resins include aromatic diisocyanates such as tolylene diisocyanate, xylylene diisocyanate, methylene diphenyl diisocyanate, phenylene diisocyanate, naphthalene diisocyanate, and tolidine diisocyanate; - Aliphatic diisocyanates having aromatic rings such as tetramethylxylylene diisocyanate; aliphatic diisocyanates such as methylene diisocyanate, propylene diisocyanate, lysine diisocyanate, trimethylhexamethylene diisocyanate and hexamethylene diisocyanate; Alicyclic diisocyanates such as methane diisocyanate and isopropylidene dicyclohexyl diisocyanate are exemplified. These may be used alone or in combination of multiple types.

A chain extender may be used when synthesizing the polyurethane resin, and the chain extender is not particularly limited as long as it has two or more active groups that react with isocyanate groups. Alternatively, a chain extender having two amino groups can be mainly used.

Examples of chain extenders having two hydroxyl groups include aliphatic glycols such as ethylene glycol, propylene glycol and butanediol; aromatic glycols such as xylylene glycol and bishydroxyethoxybenzene; ester glycols such as neopentyl glycol hydroxypivalate. Glycols such as

Examples of chain extenders having two amino groups include aromatic diamines such as tolylenediamine, xylylenediamine and diphenylmethanediamine; ethylenediamine, propanediamine, hexanediamine, 2,2-dimethyl-1,3-propanediamine, 2-methyl-1,5-pentanediamine, trimethylhexanediamine, 2-butyl-2-ethyl-1,5-pentanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, etc. Alicyclic diamines such as 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, dicyclohexylmethanediamine, 1,4-diaminocyclohexane, 1,3-bisaminomethylcyclohexane, etc. mentioned.

The content of compound (C) in the present composition is preferably 2 to 50% by mass, more preferably 5 to 40% by mass, more preferably 8 to 35% by mass, as a proportion of the total nonvolatile components in the present composition. % by weight, more preferably in the range of 10 to 25% by weight. By setting the content to 2% by mass or more, it is possible to achieve both the formation of an uneven structure by phase separation and the improvement of coating properties when the present composition is used as a coating liquid. Moreover, by setting the content to 50% by mass or less, the content of one resin can be secured, and the unevenness forming performance due to phase separation can be appropriately adjusted.

(((particularly preferred form)))
As the compounds (A), (B) and (C) contained in the present composition, (a) a release agent and a cross-linking agent, and (b) a combination of a release agent, a binder resin and a cross-linking agent are particularly preferred.

((Compound (D)))
The present composition must contain (D) fine particles (compound (D)). By using fine particles in combination, it is possible to further improve the surface hardness of the projections in the cured resin layer having the uneven structure. By increasing the surface hardness of the projections, even when the laminated polyester film is rolled, the projections on the surface of the cured resin layer are less likely to deform, and a good roll appearance can be obtained. In addition, by containing fine particles, the surface of the cured resin layer can be easily made to have a desired roughness. easier to adjust.

Examples of the fine particles include inorganic particles such as silica, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, calcium phosphate, magnesium phosphate, kaolin, aluminum oxide and titanium oxide, crosslinked silicone resin particles, crosslinked acrylic resin particles, Examples include crosslinked polymers such as crosslinked styrene-acrylic resin particles and crosslinked polyester particles, and organic particles such as calcium oxalate and ion exchange resins. Among these, silica and aluminum oxide are preferred.

The average particle size of the fine particles is preferably 1 to 100 nm, more preferably 2 to 60 nm, still more preferably 3 to 30 nm. When the average particle diameter is within such a range, it is possible to suppress the generation of coarse projections due to particle aggregation and contamination of the process due to falling off of particles, making it easier to obtain a desired fine uneven structure.
The method of measuring the average particle diameter of the fine particles is a method of calculating from the specific surface area and the density of the particles measured by a specific surface area measuring device, or by observing with a transmission electron microscope (TEM) or a scanning electron microscope (SEM). There are a method of calculating the diameter of particles and a method of determining the diameter from measurement by a dynamic light scattering method.

The content of the fine particles in the present composition is preferably 1 to 50% by mass, more preferably 5 to 45% by mass, more preferably 10 to 40% by mass, as a proportion of the total nonvolatile components in the present composition. Even more preferably, it is in the range of 25 to 35% by mass. By setting the content in such a range, it is possible to obtain a desired fine concave-convex structure while improving the surface hardness of the convex portions.

((Compound (E)))
When a cross-linking agent is included as the compound (B), the composition may further include a cross-linking catalyst (E) (compound (E)). The cross-linking catalyst (E) is used to increase the reactivity of the cross-linking agent, and various known catalysts can be used. For example, amine compounds, salts of amine compounds, aromatic sulfonic acid compounds such as p-toluenesulfonic acid, organic acids such as phosphoric acid compounds and their salts, imine compounds, amidine compounds, guanidine compounds, organometallic compounds, zinc stearate and metal salts such as zinc myristate, aluminum stearate and calcium stearate. Among these, amine compounds, salts of amine compounds, and p-toluenesulfonic acid are preferred, and amine compounds and salts of amine compounds are more preferred.

When the present composition contains a cross-linking catalyst, the content of the cross-linking catalyst in the present composition is preferably 0.01 to 5% by mass, more preferably 0.01 to 5% by mass, as a proportion of all non-volatile components in the present composition. It is in the range of 1 to 4% by mass, more preferably 1 to 3% by mass. By setting the content in such a range, the decrease in pot life can be suppressed, and the unevenness forming performance due to phase separation is sufficient.

((Other ingredients))
In addition to the above components, antifoaming agents, coatability improvers, surfactants, thickeners, organic lubricants, ultraviolet absorbers, antioxidants, and foaming agents are used as long as they do not impair the gist of the present invention. , dyes, pigments, and other additives may be added as appropriate.

(((solvent)))
The composition may be diluted with a solvent to form a coating liquid. That is, the present composition may be applied, for example, to the present polyester film as a liquid coating liquid, dried and cured as necessary to form a resin layer.
In addition, each component (compound (A), compound (B), fine particles (D), optionally added binder resin (C), cross-linking catalyst (E), other components, etc.) constituting the present composition is a solvent may be dissolved in or dispersed in a solvent.
When used as a coating liquid, the concentration of all non-volatile components in the present composition in the coating liquid is preferably 0.1 to 50% by mass. If it is 0.1% by mass or more, a resin layer having a desired thickness can be efficiently formed. On the other hand, if it is 50% by mass or less, the appearance of the resin layer can be improved by suppressing the viscosity during coating, and the stability in the coating liquid can be enhanced.

The solvent is not particularly limited, and both water and organic solvents can be used. From the viewpoint of environmental protection, it is preferable to use water as the main solvent (50% by mass or more of the total solvent) to form an aqueous coating solution. The water content is preferably 60% by mass or more, more preferably 70% by mass or more. The aqueous coating liquid may contain a small amount of organic solvent. The specific amount of the organic solvent is preferably equal to or less than the amount of water on a mass basis. .
Organic solvents used in combination with water include alcohols such as ethanol, isopropanol, ethylene glycol and glycerin; ethers such as ethyl cellosolve, t-butyl cellosolve, propylene glycol monomethyl ether and tetrahydrofuran; ketones such as acetone and methyl ethyl ketone; ethyl acetate. and amines such as dimethylethanolamine. These can be used singly or in combination. By appropriately selecting and including these organic solvents in the aqueous coating liquid as necessary, the stability and coatability of the coating liquid can be improved in some cases.

When only an organic solvent is used as the solvent, the organic solvent includes aromatic hydrocarbons such as toluene; aliphatic hydrocarbons such as hexane, heptane and isooctane; esters such as ethyl acetate and butyl acetate. ketones such as ethyl methyl ketone and isobutyl methyl ketone; alcohols such as ethanol and 2-propanol; ethers such as diisopropyl ether and dibutyl ether. These may be used singly or in combination of two or more in consideration of solubility, coatability, boiling point, and the like.

In the resin layer, each component constituting the composition (compound (A), compound (B), fine particles (D), optionally added binder resin (C), crosslinking catalyst (E), other components, etc.) ), a compound after the reaction, or a mixture thereof.
Incidentally, the analysis of each component in the resin layer can be performed by, for example, TOF-SIMS, ESCA, fluorescent X-rays, and the like.

<Method for forming cured resin layer>
Next, a method for forming the cured resin layer that constitutes the laminated polyester film will be described.
The present resin layer may be formed by applying the present composition to a polyester film and, if necessary, performing treatments such as drying, curing, heat treatment, etc. on the applied present composition, and at least heat treatment. is preferred. Moreover, it is preferable to cure the curable resin composition by heat treatment. The method of applying the cured resin composition is not particularly limited, and conventionally known coating methods such as reverse gravure coating, direct gravure coating, roll coating, die coating, bar coating and curtain coating can be used.

Moreover, as a method of forming the resin layer, there are in-line coating and off-line coating. The method of heat-treating the applied resin composition is not particularly limited. It is preferable to perform the heat treatment for 40 seconds as a guideline. On the other hand, when the resin layer is provided by in-line coating, it is generally preferable to perform heat treatment at 70 to 280° C. for 3 to 200 seconds.
Moreover, the heat treatment may be performed in two or more stages with different temperatures within the above temperature range. At least part of the heat treatment may be performed by heating during stretching. Drying and curing are preferably performed together by heating in the heat treatment.

In the present invention, the resin layer is preferably formed by in-line coating, which treats the film surface during the process of forming the polyester film.
In-line coating is a method of coating within the polyester film manufacturing process. Specifically, it is a method of coating at any stage from melt extrusion of polyester to stretching, heat setting and winding. . Usually, it is coated on an unstretched sheet obtained by melting and quenching, a stretched uniaxially stretched film, a biaxially stretched film before heat setting, or a film after heat setting and before winding up.

Although not limited to the following, for example, in sequential biaxial stretching, a method of coating a uniaxially stretched film stretched in the longitudinal direction (machine direction) and then stretching in the transverse direction is excellent. According to such a method, since film formation and resin layer formation can be performed simultaneously, there is an advantage in terms of manufacturing cost, and since stretching is performed after coating, the thickness of the resin layer can be changed by the stretching ratio. It is possible to perform thin film coating more easily compared to off-line coating films.

Further, by providing the resin layer on the film before stretching, the resin layer can be stretched together with the polyester film, thereby firmly adhering the resin layer to the polyester film.

Furthermore, in the production of biaxially stretched polyester film, the film can be restrained in the vertical and horizontal directions by stretching while holding the ends of the film with a clip or the like. High temperature can be applied while maintaining flatness without entering etc.
Therefore, since the heat treatment applied after coating can be performed at a high temperature that cannot be achieved by other methods, the film-forming property of the resin layer is improved, and the resin layer and the polyester film can be adhered more firmly. Furthermore, a strong resin layer can be formed, and performances such as resistance to migration to various functional layers that can be formed on the resin layer and resistance to moist heat can be improved.

In addition, regardless of off-line coating or in-line coating, heat treatment and active energy ray irradiation such as ultraviolet irradiation may be used together as needed. The polyester film constituting the present laminated polyester film may be previously subjected to a surface treatment such as corona treatment or plasma treatment.

The coating amount of the non-volatile component of the resin layer is preferably 0.005 to 0.95 g/m ² , more preferably 0.01 to 0.5 g/m ² , still more preferably 0.02 to 0.2 g/m 2 . ² , more preferably 0.02 to 0.15 g/m ² , still more preferably 0.02 to 0.10 g/m ² , especially 0.03 to 0.08 g/m ² preferable.
If the coating amount is within such a range, a fine uneven structure can be formed by phase separation.
The coating amount can be obtained by calculation from the non-volatile component concentration of the coating liquid, the coating amount before drying derived from the consumption of the coating liquid, the transverse stretching ratio, and the like.
Moreover, the coating amount of the non-volatile component is the coating amount in the present laminated polyester film, for example, when drying and stretching are performed, it is the coating amount after drying and stretching. The coating amount of the non-volatile component can also be said to be an index indicating the thickness of the cured resin layer, which is represented by the weight per unit area.

The cured resin layer according to the present invention is a cured product of a curable resin composition formed from the resin composition described above.
The preferred range of the thickness of the cured resin layer is as described for the amount of non-volatile component applied. can be formed. As a result, the smoothness of the surface of the cured resin layer is improved, and both the average surface roughness (Sa) and the maximum peak height (Sp) can be reduced.
In particular, when the polyester film provided with the cured resin layer has an A/B/C configuration, the surface layer on the side in contact with the cured resin layer does not substantially contain particles, and the base layer B contains particles, This is more effective because it can reduce the influence of fine irregularities on the surface of the surface layer, which is the underlying layer, on the formation of irregularities on the surface of the cured resin layer (for example, the effect of pushing up from the surface layer).

In the resin layer, each component constituting the present composition ((A) release agent, (B) cross-linking agent, (D) fine particles, optionally added (C) binder, (E) cross-linking catalyst and others components, etc.), compounds after reaction, or mixtures thereof.
The analysis of each component in the resin layer can be performed by TOF-SIMS, ESCA, fluorescent X-rays, or the like.

(air leak evaluation)
An air leakage index can be used as an index for evaluating handling properties such as windability of the present laminated polyester film. If the air leakage index is low, air trapped in the laminated polyester film when it is rolled up can be easily released, and defects in the appearance of the roll such as wrinkles and uneven edges can be prevented. In addition, when the air leakage index is high, the trapped air escapes after a sufficient period of time, especially during transportation, causing problems such as displacement of the film in the winding core direction and scratches due to displacement.
The air leakage index of the present laminated polyester film is, for example, 20,000 seconds or less, preferably 10,000 seconds or less, more preferably 8,000 seconds or less, and particularly preferably 6,000 seconds or less. By satisfying the above range, the air between the films can be easily released, wrinkles and the like can be prevented, the windability can be improved, and a good roll appearance can be obtained.

The cured resin layer in the present invention is characterized in that it forms a phase-separated structure and has a fine uneven structure by being composed of a composition having a specific constitution. Furthermore, taking into consideration the risk of wrinkles when the roll film is formed, fine particles are also used in order to improve the surface hardness of the projections. Based on the above design concept, it has become possible to form a fine uneven structure while precisely controlling it, which is difficult to achieve with the conventional particle kneading type film manufacturing method.

[Release layer]
The polyester film roll of the present invention preferably has a release layer on the film surface opposite to the surface on which the cured resin layer of the laminated polyester film is provided.
The release layer is preferably laminated on the surface side of the film having an average surface roughness (Sa) of 0.1 nm or more and 15 nm or less.
Therefore, for example, when the polyester film has an A/B/A structure, the cured resin layer is laminated on the film surface opposite to the release layer surface, and the release layer/A/B/A/cured resin layer Configuration.
When a release layer is provided, by laminating a cured resin layer having an uneven structure on the rough surface side of the film, the film winding property is improved, and an ultra-thin ceramic layer is laminated to form a green sheet. It is preferable because pinholes and the like are less likely to occur during molding.

In the laminated polyester film, the release layer is laminated on the film surface opposite to the surface on which the cured resin layer is provided.
The release layer is formed from a release agent composition containing a release agent, and from the viewpoint of obtaining good release performance, the release agent composition preferably contains a silicone resin. Specifically, it is preferable to contain a type containing a curable silicone resin as a main component, a modified silicone type obtained by graft polymerization with an organic resin such as a polyurethane resin, an epoxy resin, an alkyd resin, or a fluorosilicone resin. .

As the curable silicone resin, it is possible to use any existing curing reaction type such as addition type, condensation type heat curing type, ultraviolet curing type electron beam curing type, etc. In addition, multiple types of curing type silicone resins can be used. may be used together.
In addition, there is no particular limitation on the coating form of the curable silicone resin when forming the release layer, and it may be dissolved in an organic solvent, in the form of an aqueous emulsion, or in the form of no solvent. .

The release agent composition that forms the release layer may also contain binders, antifoaming agents, coatability improvers, thickeners, inorganic organic particles, organic lubricants, antistatic agents, if necessary. agents, conductive agents, ultraviolet absorbers, antioxidants, foaming agents, dyes, pigments, and the like.

Formation of the release layer is provided by coating the present film with a release agent composition, in-line coating performed within the film forming process, or so-called offline coating, which is applied outside the system on the film once produced. You can adopt either.

Examples of methods for providing a release layer on the film include conventionally known coating methods such as reverse gravure coating, direct gravure coating, roll coating, die coating, bar coating, and curtain coating.

The curing conditions for forming the release layer are not particularly limited. The heat treatment is preferably performed for 40 seconds, more preferably at 120 to 180° C. for 3 to 40 seconds.

Moreover, you may combine heat processing and active-energy-ray irradiation, such as ultraviolet irradiation, as needed. As an energy source for curing by irradiation with active energy rays, known devices and energy sources can be used.

The coating amount (after drying) of the release layer is usually 0.005-5 g/m ² , preferably 0.005-1 g/m ² , more preferably 0.005-0. It is in the range of 1 g/ ^m2 . When the coating amount (after drying) is 0.005 g/m ² or less, the coatability is stable and it becomes easy to obtain a uniform coating film. On the other hand, if it is 5 g/m ² or less, it is possible to prevent thick coating and prevent deterioration of coating film adhesion, curability, etc. of the release layer itself.

The amount of coating is determined by calculation from the amount of liquid per coating time (before drying), non-volatile content concentration of coating liquid, coating width, stretching ratio, line speed, and the like.

(Application of laminated polyester film)
The film can be suitably used for various release applications.
For example, it can be used for various release and process applications such as dry film resist (DFR), multilayer circuit board, ceramic green sheet production for laminated ceramic capacitors, etc. Among them, it is more preferably used for sheet molding. The present film is used, for example, as a support in release applications and process applications, and for example, various materials such as ceramic slurry may be applied or laminated on at least one surface of the support.
When the present resin layer is provided only on one side, various materials are preferably applied or laminated on the film surface opposite to the surface provided with the cured resin layer (opposite surface). It may be coated or laminated on the film surface side provided with the resin layer. In the present film, various materials may be applied or laminated on the release layer provided on the side opposite to the surface provided with the cured resin layer.

In particular, as described above, the polyester film roll of the present invention has high smoothness, a good air leakage index, minimal wrinkle generation, and improved roll windability. As the roll productivity improves, the film can be made even longer.
For example, in the manufacturing process of a multilayer ceramic capacitor, if it is used as a support for a ceramic green sheet, a uniform thin dielectric layer can be formed, and the polyester film roll is reduced in switching frequency due to lengthening. , can contribute to productivity improvement. In particular, it can be suitably used as a support for a ceramic green sheet used in multilayer ceramic capacitors for automobiles.

<<<explanation of words>>>
In the present invention, the term "film" includes the "sheet", and the term "sheet" includes the "film".
In the present invention, when described as "X to Y" (X and Y are arbitrary numbers), unless otherwise specified, "X or more and Y or less" and "preferably larger than X" or "preferably Y It also includes the meaning of "less than".
In addition, when described as "X or more" (X is an arbitrary number), it includes the meaning of "preferably greater than X" unless otherwise specified, and is described as "Y or less" (Y is an arbitrary number). If not otherwise specified, it also includes the meaning of "preferably smaller than Y".

EXAMPLES The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

<Production of polyester>
[Polyester (A)]
100 parts by mass of dimethyl terephthalate and 65 parts by mass of ethylene glycol were charged into a transesterification reactor equipped with a stirrer, a heating device and a distillate separation tower, and heated to 150° C. to melt the dimethyl terephthalate.

Then, an ethylene glycol solution of magnesium acetate tetrahydrate was added so that the amount of magnesium acetate added to the obtained polyester was 0.09% by mass.
Thereafter, the temperature was raised to 225°C over 3 hours under normal pressure, and the mixture was further stirred and held at 225°C for 1 hour and 15 minutes, and the transesterification reaction was carried out while distilling off methanol to substantially complete the transesterification reaction. A polyester low polymer (oligomer) was obtained.

The oligomer was then transferred to a stirred polycondensation reactor equipped with a distillation tube.
An ethylene glycol solution of magnesium acetate tetrahydrate was added to the transferred oligomer so that the amount of magnesium acetate added to the obtained polyester resin content was 0.09% by mass.
Thereafter, an ethylene glycol solution of phosphoric acid was added as a heat stabilizer so that the amount of phosphoric acid added to the resulting polyester was 0.017% by mass.

Then, an ethylene glycol solution of tetrabutyl titanate as a polycondensation catalyst was added to the oligomer so that the amount of titanium atoms in the obtained polyester was 4.5 ppm by mass.
After that, the pressure was reduced from 101.3 kPa to 0.4 kPa in 85 minutes, and the pressure was maintained at 0.4 kPa. was performed to obtain a polyester A having an intrinsic viscosity (IV) of 0.63 dL/g.

[Polyester (B)]
Instead of adding tetrabutyl titanate in polyester (A), polyester (A) except that antimony trioxide is added as a polycondensation catalyst so that the amount of antimony atoms is 300 ppm by mass with respect to the polyester resin content obtained. In the same manner as above, a polyester (B) having an intrinsic viscosity (IV) of 0.63 dl/g was obtained.

[Polyester (C)]
0.75% by mass of alumina particles having an average particle size (average primary particle size) of 0.05 μm are added to the polyester (A), and kneaded using a vented twin-screw kneader to obtain an intrinsic viscosity (IV) of 0.63 dL/g of polyester (C) was obtained.

A curable resin composition obtained by stirring and mixing the composition shown in Table 1 below was diluted with water to prepare a coating liquid for each example and comparative example. The compounds used are as follows.

[Compound (A): release agent]
300 g of oxidized polyethylene wax having a melting point of 105° C., an acid value of 16 mg KOH/g, a density of 0.93 g/mL, and a number average molecular weight of 5000, and ion-exchanged water of 650 g were placed in an emulsification facility with a capacity of 1.5 L equipped with a stirrer, thermometer, and temperature controller. 50 g of decaglycerin monooleate surfactant and 10 g of 48% potassium hydroxide aqueous solution were added and replaced with nitrogen. Wax emulsion passed and cooled to 40°C.

[Compound (B): cross-linking agent]
Melamine compound: Hexamethoxymethylol melamine

[Compound (C): binder resin]
Aqueous dispersion of acrylic resin polymerized with the following composition Emulsion polymer of ethyl acrylate/n-butyl acrylate/methyl methacrylate/N-methylolacrylamide/acrylic acid = 65/21/10/2/2 (mass%) (emulsifier: anionic surfactant)

[Compound (D): fine particles]
Silica particles with an average particle size of 0.005 μm

[Compound (E): Crosslinking catalyst]
2-amino-2-methylpropanol hydrochloride

[Example 1]
A raw material containing 100% by mass of polyester A was used as a raw material for the surface layer A, and a raw material containing 100% by mass of polyester B was used as a raw material for the intermediate layer B. Each raw material was supplied to three extruders and melted at 280 ° C. After that, a two-kind three-layer (A / B / A) layer structure in which the A layer is the surface layer and the B layer is the intermediate layer, and the thickness composition ratio is A / B / A = 1.6 / 27.8 / 1 It was co-extruded so as to have a thickness of 0.6, and cooled and solidified on a cooling roll set at 25° C. to obtain an unstretched film.

Then, this film was stretched 3.5 times in the machine direction (MD direction) while passing through a group of heating rolls at 86°C. After that, the longitudinally stretched film was coated on one side of surface layer A with a coating solution of the following curable resin composition so that the thickness after stretching and drying was 0.06 g/m ² , and the film was led to a tenter stretching machine in the transverse direction ( After stretching 4.5 times at 105 ° C. in the TD direction) and further heat-treating at 230 ° C., a 2% relaxation treatment is performed in the width direction to obtain a laminated polyester film having a thickness of 31 μm. It was wound up into a polyester film roll.

The obtained film had a cured resin layer formed from a cured resin composition having the following composition.
(A) Release agent: 32% by mass
(B) Crosslinking agent: 18% by mass
(C) Binder resin: 15% by mass
(D) Fine particles: 33% by mass
(E) Crosslinking catalyst 2% by mass

[Examples 2 to 4]
A polyester film roll was obtained in the same manner as in Example 1, except that the thickness of the cured resin layer and the composition of the cured resin layer were changed.

[Example 5]
A raw material obtained by mixing polyesters A and C at a ratio of 87% by mass and 13% by mass is used as a raw material for surface layer A, and a raw material containing 100% by mass of polyester A is used as a raw material for layer B and surface layer C, and each of the raw materials is used in three units. After being supplied to an extruder and melted at 280 ° C., each of the surface layers A and C is the surface layer, and the layer B is the intermediate layer. were coextruded so that A/B/C=1.6/27.8/1.6, and cooled and solidified on a cooling roll whose surface temperature was set to 25° C. to obtain an unstretched film.

Then, this film was stretched 3.5 times in the machine direction (MD direction) while passing through a group of heating rolls at 86°C. After that, a coating solution of a curable resin composition is applied to the surface layer C side of this longitudinally stretched film so that the thickness after stretching and drying becomes 0.06 g/m ² , and the film is led to a tenter stretching machine in the transverse direction. (TD direction) was stretched 4.5 times at 105 ° C., further heat treated at 230 ° C., and then subjected to 2% relaxation treatment in the width direction to obtain a laminated polyester film having a thickness of 31 μm. was wound up to make a polyester film roll.

[Examples 6-7]
In Example 5, a polyester film roll was obtained in the same manner as in Example 1, except that the thickness of the cured resin layer and the composition of the cured resin layer were changed.

[Comparative Example 1]
A polyester film roll was obtained in the same manner as in Example 1, except that the thickness of the cured resin layer and the composition of the cured resin layer were changed.

[Comparative Example 2]
A polyester film roll was obtained in the same manner as in Example 2, except that the thickness of the cured resin layer and the composition of the cured resin layer were changed.
The properties of each film roll obtained are shown in Table 1 below.

<Measurement and evaluation method>
Measurement methods and evaluation methods used in Examples and Comparative Examples are as follows. The measurement and evaluation results are summarized in Table 1.

(1) Intrinsic viscosity (IV)
Accurately weigh 1 g of polyester, add 100 mL of a mixed solvent of phenol / tetrachloroethane = 50/50 (mass ratio) to dissolve, and use a viscosity (IV) measuring device (Rigosha "VMS-022UPC F10"). , 30°C.

(2) Average particle size and particle size distribution of particles Using a scanning electron microscope (manufactured by HITACHI, "S3400N"), powder was observed from the A layer side of the polyester film of the polyester film roll of Examples and Comparative Examples. . The size of each particle was measured from the obtained image data, and the average value of 10 points was taken as the average particle size (average primary particle size).
Further, (D90-D10)/D50 of particles can be calculated as follows. A dispersion with a solid content of 0.03 g/mL is prepared by adding a mixed solvent of phenol/tetrachloroethane = 2/3 to the particles, and the dispersion is subjected to a laser diffraction scattering method using “MT3300EXII” manufactured by Microtrack Bell. By measuring the particle diameter D10 at which the cumulative number is 10%, the particle diameter D50 at which the cumulative number is 50%, and the particle diameter D90 at which the cumulative number is 90%, (D90-D10)/D50 is calculated.

(3) Average surface roughness (Sa), maximum peak height (Sp)
Using a surface roughness measuring instrument (Ametech Co., Ltd., "NewView" (registered trademark)), the A layer side and the cured resin layer side (that is, there is a C layer) of the laminated polyester film of the polyester film rolls of Examples and Comparative Examples In this case, the surface of C layer side) was measured, and the average surface roughness Sa value and the maximum peak height Sp value were obtained from the obtained surface profile curve (Both Sa and Sp are the maximum values for 36 measurement points・The average of 30 measured values excluding the three minimum values was used as the Sa value and the Sp value).

(4) Concavo-convex Structure of Cured Resin Layer Measurement was performed under the following conditions using a scanning probe microscope (SPM-9700 manufactured by Shimadzu Corporation).
Probe: Silicon cantilever Scanning mode: Dynamic mode Scanning range: 25 μm × 25 μm
Scanning speed: 0.8Hz
Number of pixels: 512 × 512 data points Observe the cross-sectional shape of 25 μm width from the obtained data. When no protrusions or recesses could be confirmed, it was determined that the uneven structure was "absent".
All of the curable resin layers of the present examples and comparative examples had the concave-convex structure.

(5) Load length ratio (Rmr(80)) of cured resin layer surface
Cross-sectional analysis with a scanning probe microscope was performed in the same manner as in (4) above, and the load length ratio (Rmr(80)) at a cutting level of 80% was determined. Cross-sectional analysis data were obtained at 10 points at equal intervals in the film-forming direction (that is, the longitudinal direction) of the film, and these were averaged.

(6) Root-mean-square gradient (Sdq) and protruding peak height (Spk) of cured resin layer surface
The surface of the laminated polyester film provided with the cured resin layer of the polyester film rolls of Examples and Comparative Examples was observed using an AFM (Shimadzu Corporation, SPM-9700) in the same manner as in (4) above. The image data was analyzed using image analysis software SPIP6.2.5 ImageMetrology to calculate the root mean square gradient (Sdq) and the peak height (Spk).

(7) Air Leakage Index Using a Digivec smoothness tester (manufactured by Toyo Seiki Co., Ltd., "DB-2"), measurements were made in accordance with JIS P8119 at a temperature of 23°C and a humidity of 50% RH. The pressure of the pressure device is 100 kPa, and the vacuum vessel has a volume of 38 ml. The time for 1 mL of air to flow, that is, the time (seconds) until the pressure inside the vessel changes from 50.7 kPa to 48.0 kPa, is measured. 10 times the obtained number of seconds was taken as the air leakage index. The sample size of the test film was 70 mm square, and 20 test films were laminated so that the front and back sides of the test film overlapped to obtain a laminated film for test.
A hole with a diameter of 5 mm was made in the center of the laminated film for testing, and the air leakage index was measured as described above. The larger the value of this air leakage index, the longer it takes for air to leak from the gaps between the films, so it indicates that the films are in closer contact, and the risk of wrinkles when made into a roll film. is large.

The polyester film rolls of Examples 1 to 7 all had an air leakage index of 20,000 seconds or less, indicating that the risk of wrinkles when formed into roll-shaped films is small.
Further, from the results of Examples 1 to 7, in order to achieve both low Sa and high Sdq on the surface of the cured resin layer, it is necessary to form unevenness by combining cured resin compositions having a specific configuration. .
Furthermore, in Comparative Examples 1 and 2, since it is difficult to achieve both low Sa and high Sdq, the air leakage index is large, and the risk of wrinkles when formed into a roll film is high. This is because, in the concave-convex structure formed by phase separation, the convex structures of Examples 1 to 7 are steep, whereas the convex structures of Comparative Examples 1 and 2 are gentle. It is presumed that the formation of a part led to the decrease in the air leakage index.
The cured resin layer in the present invention is characterized in that it forms a phase-separated structure and has a fine uneven structure by being composed of a composition having a specific constitution. Furthermore, taking into account the risk of wrinkling when the roll film is formed, fine particles are used in combination in order to sharpen the shape of the projections. Based on the above design concept, it has become possible to form a fine uneven structure while precisely controlling it, which is difficult to achieve with the conventional particle kneading type film manufacturing method.

The polyester film roll of the present invention has high smoothness, a good air leakage index, minimal wrinkle generation, and improved roll windability. , further lengthening of the film is possible.
For example, in the manufacturing process of a multilayer ceramic capacitor, if it is used as a support for a ceramic green sheet, a uniform thin dielectric layer can be formed, and the polyester film roll is reduced in switching frequency due to lengthening. , can contribute to productivity improvement. In particular, it can be suitably used as a support for a ceramic green sheet used in multilayer ceramic capacitors for automobiles.

Claims (17)

A polyester film roll obtained by winding a polyester film and a laminated polyester film having a cured resin layer on at least one side of the polyester film,
A polyester film roll in which the laminated polyester film satisfies all of the following requirements (1) to (4).
(1) The cured resin layer has an uneven structure.
(2) The cured resin layer is formed from a cured resin composition containing (A) a release agent, (B) a cross-linking agent, and (D) fine particles.
(3) The average surface roughness (Sa) of the surface of the cured resin layer is 1 to 9 nm.
(4) The root-mean-square gradient (Sdq) of the cured resin layer surface is 0.40 to 0.80. The polyester film roll according to claim 1, wherein the ratio (Sp/Sa) between the maximum peak height (Sp) and the average surface roughness (Sa) of the surface of the cured resin layer is 30 or less. The polyester film roll according to claim 1 or 2, wherein the height (Spk) of protruded peaks on the surface of the cured resin layer is 70 nm or more. The polyester film roll according to any one of claims 1 to 3, wherein the cured resin composition contains (C) a binder resin. (C) The polyester film roll according to claim 4, wherein the binder resin contains one or more selected from the group consisting of (meth)acrylic resin and polyvinyl alcohol. The polyester film roll according to any one of claims 1 to 5, wherein the cured resin layer has a thickness of 0.02 to 0.15 g/ ^m2 in weight per unit area. The polyester film roll according to any one of claims 1 to 6, wherein the content of (A) the release agent in the cured resin composition is 5 to 90 mass% as a non-volatile component. The polyester film is a polyester film having at least a three-layer structure having a surface layer, an intermediate layer, and a surface layer in this order,
The polyester film roll according to any one of claims 1 to 7, wherein the cured resin layer is provided so as to be in contact with one of the surface layers. The polyester film roll according to any one of claims 1 to 8, wherein the intrinsic viscosity (IV) of the polyester constituting the surface layer of the polyester film is 0.50 dL/g or more. The polyester film roll according to any one of claims 1 to 9, wherein the surface layer of the polyester film contains a titanium compound. The polyester film roll according to any one of claims 1 to 10, wherein the surface layer of the polyester film contains at least one of an antimony compound and a titanium compound, and the content of the antimony compound is 100 ppm or less. The polyester film roll according to any one of claims 1 to 11, wherein one surface layer of said polyester film is substantially free of particles. 13. The polyester film roll of Claim 12, wherein the other surface layer of said polyester film is substantially free of particles. The polyester film roll according to any one of claims 1 to 13, wherein the polyester film has an average surface roughness (Sa) of 1 to 9 nm on the surface layer opposite to the surface on which the cured resin layer is provided. The polyester film roll according to any one of claims 1 to 14, which has a release layer on the film surface opposite to the surface on which the cured resin layer is provided. The polyester film roll according to any one of claims 1 to 15, which is used as a support for ceramic green sheets in the manufacturing process of laminated ceramic capacitors. The polyester film roll according to any one of claims 1 to 16, which is used as a support for ceramic green sheets in the manufacturing process of ceramic capacitors for automobiles.