Laminated polyester film and method for manufacturing polyester film

Abstract

The objective of this invention is to provide a laminated polyester film with high reusability and suitability for subsequent processing steps. A laminated polyester film comprises a polyester film and a layer X satisfying the following conditions: Condition 1: 20 ≤ γX P ≤ 45; Condition 2: 3.0 ≤ γX H ≤ 10; γX P (mN / m): polar component of the surface free energy of layer X; γX H (mN / m): hydrogen bond component of the surface free energy of layer X.

Description

[Technical Field]

[0001] The present invention relates to a laminated polyester film that is excellent in removing layers disposed on a laminated polyester film. [Previous Technology]

[0002] Plastics are used in various fields, but on the other hand, they are considered a cause of marine pollution such as microplastics, making it urgent to reduce the environmental burden caused by plastics. Furthermore, in recent years, due to the development of the Internet of Things (IoT), electronic components such as central processing units (CPUs) in computers or smartphones have increased dramatically. Consequently, the number of multilayer ceramic capacitors (MLCCs), crucial for driving these electronic components, has also increased explosively. A typical manufacturing method for MLCCs involves stacking ceramic green sheets and electrodes onto a release film (with a release layer on the plastic film substrate), drying and fixing the stack, then peeling the stack off the release film, stacking multiple layers, and firing. In this step, the release film is discarded as an unwanted material.

[0003] That is, due to the explosive increase in the number of MLCCs in recent years, the environmental burden caused by the increase in release films discarded as unwanted materials has gradually become a problem. From the point of view of release properties, the release layer contained in the release film used in the manufacturing process of MLCCs generally has a different composition from the composition of the film. Therefore, when the release film with the release layer is directly remelted, the components of the release layer exist as foreign matter and are therefore difficult to reuse.

[0004] Therefore, as an example of a technology for reusing a release film, Patent Document 1 discloses a method for cleaning a release film having a release layer using a metal brush and reusing the film after the release layer has been removed. Furthermore, Patent Document 2 discloses a method for providing a layer of water-soluble resin between the release layer and the polyester film, removing the release layer by washing with water, and then reusing the film. Moreover, Patent Document 3 discloses a method in which ceramic green sheets with good smoothness and peelability can be obtained by specifying the step conditions during ceramic green sheet lamination, and a method for providing a layer of water-soluble resin between the release layer and the polyester film, removing the release layer by washing with water, and then reusing the film. [Prior Art Documents] [Patent Documents]

[0005] Patent Document 1: Japanese Patent Application Publication No. 2012-171276; Patent Document 2: Japanese Patent No. 4284936; Patent Document 3: Japanese Patent Application Publication No. 2004-160773 [Summary of the Invention]

[0006] [The problem the invention aims to solve]

[0007] It is important to reduce the environmental burden caused by the increase in release films discarded as unwanted materials, which accompanies the explosive increase in the number of MLCCs as described above. Therefore, the laminated polyester film used as the substrate for the release film needs to be "reusable" and, for the film itself, requires processing adaptability in subsequent steps.

[0008] In response to the above requirements, the inventors reviewed the prior art and found that, in the case of the technology described in Patent Document 1, the release layer could not be removed evenly, requiring considerable effort for reuse, resulting in problems with reusability. In the case of the technology described in Patent Document 2, reusability was also insufficient. Furthermore, in the case of the technology described in Patent Document 3, post-processing was poor depending on the step conditions, and there was room for improvement in reusability.

[0009] Based on the above aspects, the object of the present invention is to provide a laminated polyester film with high reusability and suitable for subsequent processing steps. [Means for Solving the Problem]

[0010] [I] A laminated polyester film comprising a polyester film and a layer X satisfying the following conditions. Condition 1: 20 ≦ γXP ≦ 45 Condition 2: 3.0 ≦ γXH ≦ 10 γXP (mN / m): polar component of the surface free energy of layer X γXH (mN / m): hydrogen bond component of the surface free energy of layer X [II] The laminated polyester film as described in [I], wherein the thickness xa (nm) of layer X and the roughness RzjisB (nm) of the surface of the polyester film opposite to the side having layer X (side A) satisfy the following conditions. Condition 3: 1.0 ≦ RzjisB / xa ≦ 20.0 xa (nm): thickness of layer X [III] The laminated polyester film as described in [I] or [II], wherein layer X satisfies the following conditions. Condition 4: 20≦γXP≦30 Condition 5: 6.0≦γXH≦10 [IV] The laminated polyester film as described in [II] or [III] satisfies the following conditions. Condition 6: 1.5≦RzjisB / xa≦10.0 [V] The laminated polyester film as described in any one of [I] to [IV], wherein the thickness xa (nm) of layer X and the surface roughness RzjisX (nm) of layer X satisfy the following conditions. Condition 7: 0.01≦RzjisX / xa≦3.0 [VI] The laminated polyester film as described in any one of [I] to [V], wherein the thickness xa of layer X is 10 nm or more and 500 nm or less. [VII] The laminated polyester film as described in any one of [I] to [VI], wherein the water contact angles HX(1) (°) and HX(20) (°) of layer X satisfy the following conditions. Condition 8: 5≦|HX(1)-HX(20)|≦60 HX(1) (°): Contact angle after 1 second of contact between water and layer X HX(20) (°): Contact angle after 20 seconds of contact between water and layer X [VIII] A laminated polyester film as described in any one of [I] to [VII], wherein layer X comprises a resin having a polyvinyl alcohol backbone. [IX] A laminated polyester film as described in [VIII], wherein layer X comprises a resin having a sulfonate-modified polyvinyl alcohol backbone. [X] A laminated polyester film as described in any one of [I] to [IX], wherein the crystallinity of layer X is 14% or more and 40% or less. [XI] A laminated polyester film as described in [X], wherein the crystallinity of layer X is greater than 31% and 40% or less. [XII] A laminated polyester film as described in any one of [I] to [XI], wherein layer X comprises a resin with a degree of polymerization greater than 200. [XIII] The laminated polyester film as described in any one of [I] to [XII] has layers Y, X, and a polyester film that satisfy the following conditions in sequence.Condition 9: 80≦HY(1)≦120 Condition 10: 1≦|HY(1)-HY(20)|≦90 HY(1) (°): Contact angle after 1 second when water comes into contact with layer Y HY(20) (°): Contact angle after 20 seconds when water comes into contact with layer Y [XIV] As described in [XIII], the laminated polyester film wherein the solvent durability of the surface of layer Y is determined by the following method is 5% or more and 100% or less. [Method for determining solvent durability] Testing machine: Vibration testing machine (Type II friction testing machine as described in Japanese Industrial Standards (JIS) L 0849 (2013)) Friction component: Toluene:ethanol mixed solvent (mass ratio 1:1) impregnated in cotton cloth (wide fine cotton cloth No. 3) Load: 1 kg Number of cycles: 30 cycles Solvent durability (%) = F(A) / F(B)×100 F(A): Peel force on the surface of layer Y F(B): Peel force on the surface of layer Y after wiping test with solvent-impregnated cloth [XV] Laminated polyester film as described in [XIII] or [XIV] wherein the surface free energy of layer Y has a hydrogen bond component γYH of 1.5 or more and 10 or less. [XVI] Laminated polyester film as described in any one of [XIII] to [XV] for demolding purposes of setting a demolding layer on the side of layer Y opposite to the side in contact with layer X and peeling the demolding layer off layer Y. [XVII] The laminated polyester film as described in [XVI] is used for removing layers X and Y after the release layer is peeled off from layer Y. [XVIII] The laminated polyester film as described in [XVII] is used for reuse of the laminated polyester film after the layers X and Y have been removed. [XIX] The laminated polyester film as described in any one of [XVI] to [XVIII], wherein the release layer is a ceramic green sheet with barium titanate as its main component. [XX] The laminated polyester film as described in any one of [I] to [XIX] is used at least as part of a release film for a multilayer ceramic capacitor (MLCC) manufacturing process. [XXI] A laminated polyester film having a layer Y on at least one surface layer that satisfies the following conditions. Condition 11: 80≦HY(1)≦120 Condition 12: 1≦|HY(1)-HY(20)|≦90 HY(1) (°): Contact angle after 1 second after water comes into contact with layer Y HY(20) (°): Contact angle after 20 seconds after water comes into contact with layer Y [XXII] As described in any one of [I] to [XXI], the laminated polyester film has a laminated structure of three or more layers, the laminated structure of three or more layers having a layer (A layer) constituting an A surface as one surface of the polyester film, a layer (B layer) constituting a B surface as another surface, and a layer (C layer) without a surface, the C layer containing recycled polyester raw material.[XXIII] A method for manufacturing a polyester film, comprising at least the following steps: using a laminated polyester film as described in [XXII] having a release layer, a layer Y, and a polyester film in sequence, peeling the release layer from the layer Y; removing the layer Y from the film from which the release layer has been peeled off; and manufacturing recycled raw material from the film from which the release layer and layer Y have been removed, further comprising the step of using the recycled raw material to form a film. [XXIV] A laminated polyester film is a polyester film formed by laminating a layer X, which is mainly composed of a hydrophilic resin, onto one side (A side) of a polyester film, wherein the thickness xa (nm) of layer X and the surface roughness RzjisB (nm) of the polyester film on the side opposite to the side having layer X (A side) satisfy the following conditions. Condition 13: 0.2≦RzjisB / xa≦20.0 [XXV] A laminated polyester film comprising a polyester film and a layer X, wherein the laminated polyester film comprises a resin having a sulfonate-modified polyvinyl alcohol backbone, wherein the sulfonate-based copolymerization amount of the resin having the sulfonate-modified polyvinyl alcohol backbone is 0.1 mol% or more and 10 mol% or less, and when the average degree of polymerization of layer X is determined using the method described in JIS K 6726 (1994), the average degree of polymerization is 200 or more and 2400 or less, and when the degree of saponification of layer X is determined using the method described in JIS K 6726 (1994), the degree of saponification is 30 or more and 97 or less. [Effects of the Invention].

[0011] According to the present invention, a laminated polyester film with high reusability and suitable for processing in subsequent steps can be provided.

Implementation Method

[0013] The present invention will be described in detail below with specific examples.

[0014] This invention relates to a laminated polyester film having a polyester film and one or more layers. The polyester mentioned in this invention is formed having dicarboxylic acid constituents and diol constituents. Furthermore, in this specification, the term "constituent" refers to the smallest unit obtainable by hydrolyzing the polyester. Examples of dicarboxylic acid constituents constituting the polyester include: terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 4,4'-diphenyldicarboxylic acid, 4,4'-diphenyl ether dicarboxylic acid, and other aromatic dicarboxylic acids or their ester derivatives.

[0015] In addition, examples of diol components constituting the polyester include: aliphatic diols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,2-butanediol, and 1,3-butanediol; alicyclic diols such as cyclohexanediol and spiroglycerol; and polyesters formed by linking multiple of the diols. From the viewpoint of mechanical properties and transparency, polyethylene terephthalate (PET), polyethylene-2,6-naphthalene dicarboxylate (PEN), polyesters copolymerized with isophthalic acid or naphthalene dicarboxylic acid and a portion of the dicarboxylic acid component of PET, and polyesters copolymerized with a portion of the diol component of PET such as cyclohexanediol, spiroglycerol, and diethylene glycol are preferred.

[0016] A preferred embodiment of the laminated polyester film of the present invention is a laminated polyester film having a polyester film and a layer X satisfying the following conditions 1 and 2. From the viewpoint of simpler structure and higher productivity, a more preferred embodiment is a laminated polyester film having a layer X satisfying the following conditions 1 and 2 on at least one side of the polyester film. Condition 1: 20≦γXP≦45 Condition 2: 3.0≦γXH≦10 γXP (mN / m): Polar component of the surface free energy of layer X γXH (mN / m): Hydrogen bond component of the surface free energy of layer X The polar component γXP and hydrogen bond component γXH of the surface free energy refer to the following values, which are obtained by calculating the static contact angles of glycerol, ethylene glycol, methylamine, and diiodomethane relative to the surface of layer X of the laminated polyester film at 25°C, and then incorporating the static contact angles under each liquid with the dispersion component, polar component, and hydrogen bond component of the surface free energy of each liquid as described in Non-Patent Document 1 below into the "Extended Hawkes Formula of Hata and Kitasaki" described in Non-Patent Document 2 below, and solving the simultaneous equations. Details of the measurement method will be described later. Furthermore, if layer X is not exposed, it is assumed that layer X is exposed by grinding until its thickness is 30% to 70% of the original thickness, and the surface free energy of layer X is calculated. Non-patent literature 1: J. Panzer: "J. Colloid Interface Sci.", 44, 142 (1973). Non-patent literature 2: Kitasaki Yasuaki, Hata Toshio: "Journal of Japan Adhesion Association", 8, (3) 131 (1972). By setting the polar component γXP and the hydrogen bonding component γXH of the surface free energy within this range, the internal interaction of layer X itself or the interaction between layer X and the laminated polyester film becomes stronger, the solvent resistance is improved, and layer X can easily absorb water. Therefore, layer X can be easily removed from the laminated polyester film by washing with water or aqueous solution. Furthermore, the solvent resistance mentioned here refers to the fact that, for example, when a release layer is applied to layer X using a solvent-containing coating, and then a ceramic green sheet is applied to it using a solvent-containing slurry, the smoothness or washability of the laminated polyester film will not be significantly deteriorated. From the same perspective, γXP is preferably 20 mN / m or more and 30 mN / m or less, more preferably 22 mN / m or more and 28 mN / m or less; and γXH is preferably 4.0 mN / m or more and 10 mN / m or less, more preferably 6.0 mN / m or more and 10 mN / m or less, and particularly preferably 7 mN / m or more and 9 mN / m or less.

[0017] When using a resin with a polyvinyl alcohol backbone as layer X, it is a preferred embodiment to introduce ionic polar groups such as carboxylates, sulfonates, or tertiary ammonium salts as side chain groups in order to set the polar component γXP and the hydrogen bonding component γXH within this range. From the viewpoint of water solubility and solvent resistance, sulfonates are preferred. That is, layer X preferably comprises a resin with a sulfonate-modified polyvinyl alcohol backbone. As the copolymerization amount, relative to the total amount of resin with a polyvinyl alcohol backbone, it is preferably 0.1 mol% or more and 10 mol% or less, more preferably 0.5 mol% or more and 10 mol% or less, further preferably 0.5 mol% or more and 5.0 mol% or less, and particularly preferably 1.0 mol% or more and 3.0 mol% or less. Furthermore, the degree of polymerization is preferably more than 200 and less than 1000, more preferably 300 or more and less than 1000, and further preferably 400 or more and 600 or less. Furthermore, the degree of saponification is preferably 30 or higher and 90 or lower, and more preferably 60 or higher and 88 or lower. Additionally, by setting the copolymerization amount or degree of polymerization and the degree of saponification within the aforementioned ranges, it is easy to set the polar component γXP and the hydrogen bonding component γXH of the surface free energy of layer X within the aforementioned ranges.

[0018] The laminated polyester film of the present invention preferably has an absolute value (|HX(1)-HX(20)|) of the difference between the contact angle HX(1) after water contacts the layer X for 1 second and the contact angle HX(20) after water contacts the layer X for 20 seconds, which is 5° or more and 60° or less. |HX(1)-HX(20)| represents the amount of change in the contact angle of water before and after a certain period of time. If the value is small, it means that the amount of change in the contact angle of water before and after a certain period of time is small. If the value is large, it means that the amount of change in the contact angle of water before and after a certain period of time is large. By setting |HX(1)-HX(20)| to 5° or more, the water absorption of the layer X is improved, and it is easy to clean with water. In addition, by setting |HX(1)-HX(20)| to 60° or less, the layer X can be stably film-formed. Furthermore, by having |HX(1)-HX(20)| between 10° and 30°, it is less likely to be locally biased, thus further improving washability. From the aforementioned point of view, it is even more preferable to have a value between 10° and 25°. In addition, from the aforementioned point of view, it is even more preferable to have HX(1)-HX(20) ≧ 0°.

[0019] Layer X of the laminated polyester film of the present invention preferably contains a water-soluble substance. By containing a water-soluble substance in layer X, it is easy to set |HX(1)-HX(20)| as a preferred range. In addition, when layer X contains a water-soluble substance, by washing the laminated polyester film containing layer X with water, layer X dissolves into the water, removing the layer laminated on or above layer X, and it is easy to obtain a polyester film with high purity. The water-soluble substance preferably contains 60% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, and most preferably contains only the water-soluble substance, relative to the entire layer X. Furthermore, from the viewpoint of obtaining a polyester film with high purity, layer X is preferably in contact with the polyester film.

[0020] Examples of water-soluble substances include resins containing a water-soluble polyester backbone, resins containing a polyester amino carbamate backbone, resins containing a polyvinyl alcohol backbone (hereinafter, polyvinyl alcohol is sometimes referred to as PVA), resins containing a polyvinyl pyrrolidone backbone (hereinafter, polyvinyl pyrrolidone is sometimes referred to as PVP), and those with starch as the main component. Water solubility as mentioned here refers to a mass change of 15% or more when immersed in water at 50°C for 10 minutes, thus becoming an aqueous solution. The specific method is as follows. That is, water solubility means that after immersing the resin in water at 50°C for 10 minutes, removing it from the water, and measuring the mass after thoroughly wiping away water droplets adhering to the surface with a rag, the mass change ΔM calculated using the following method is 15% or more, thus becoming an aqueous solution. ΔM = |(M2-M1)| / M1×100 (%) M1 (g): Resin mass before immersion in water at 50℃ for 10 minutes M2 (g): Resin mass after immersion in water at 50℃ for 10 minutes

[0021] Furthermore, the term "principal component" refers to the component that contains 60% or more of the stated content per 100% mass of the layer.

[0022] From the viewpoint of affinity with polyester film, or water solubility and solvent resistance, layer X is preferably a resin containing a polyvinyl alcohol backbone, and layer X is more preferably a resin containing only a polyvinyl alcohol backbone. In particular, resins with a PVA backbone are preferred because they have fewer non-polar sites and contain a large number of hydrophilic groups, thus exhibiting high water solubility and solvent resistance.

[0023] When using a resin with a polyvinyl alcohol backbone as layer X, the degree of polymerization is preferably greater than 200 and less than 1000, more preferably greater than 300 and less than 1000, and even more preferably greater than 400 and less than 600. By setting the degree of polymerization to less than 1000, the molecular chains of polyvinyl alcohol become longer, suppressing encapsulation within the molecular chains, reducing crystallinity, and improving the solubility of layer X. In addition, by setting the degree of polymerization to greater than 200, when layer X is formed by coating, good coatability can be achieved, and the situation where it tends to remain on the film due to deterioration of coatability or the situation where the washability deteriorates due to increased crystallinity can be suppressed. Furthermore, the degree of polymerization refers to the average degree of polymerization calculated using JIS K 6726 (1994).

[0024] In the same viewpoint, layer X contains a resin having a polyvinyl alcohol backbone, and when the average degree of polymerization of layer X is determined using the method described in JIS K 6726 (1994), the determined average degree of polymerization is preferably greater than 200 and less than 1000, more preferably greater than 300 and less than 1000, and even more preferably greater than 400 and less than 600.

[0025] Furthermore, in view of the aforementioned point, layer X preferably contains 60% by mass or more of a resin having a polyvinyl alcohol backbone, more preferably 90% by mass or more, even more preferably 95% by mass or more, and most preferably contains only a resin having a polyvinyl alcohol backbone. Additionally, layer X preferably exhibits water solubility.

[0026] In addition, when using a resin with a polyvinyl alcohol backbone as layer X, the degree of saponification is preferably 30 or more and 90 or less, and more preferably 60 or more and 88 or less. Polyvinyl alcohol has at least hydroxyl and acetate groups as side chains. The higher the degree of saponification, the more hydroxyl groups with small volume as functional groups there are, and the less acetate groups there are. Therefore, when the degree of saponification is high, there is a tendency for crystallization caused by molecular chain encapsulation to easily occur. If the degree of saponification is set to 90 or less, the crystallinity can be reduced, and the washability can be further improved. In addition, if the degree of saponification is set to 30 or more, the amount of acetate groups can be kept below a certain level, and the washability becomes good. In addition, it is easy to set |HX(1)-HX(20)| in a better range, and the solvent resistance can be good.

[0027] Alternatively, it is also a preferred embodiment to use a copolymer of polyvinyl alcohol (PVA) copolymerized from side chains with functional groups other than hydroxyl or acetic acid groups as the resin having a PVA backbone for layer X. In particular, by introducing hydrophilic and bulky functional groups, such as sulfonates, it is easy to set the range of γXP and γXH, |HX(1)-HX(20)| to a preferred range. Among these, sulfonic acid is preferred from the viewpoint of water solubility and solvent resistance. That is, layer X preferably contains a resin having a sulfonate-modified PVA backbone. As the copolymerization amount, relative to the total amount of resin having a PVA backbone, it is preferably 0.1 mol% or more and 10 mol% or less, more preferably 0.5 mol% or more and 5.0 mol% or less, and even more preferably 1.0 mol% or more and 3.0 mol% or less. If the copolymer amount is set within the range described above, the coatability becomes good when layer X is formed by coating, and the situation where the film tends to be biased and the crystallinity becomes too high can be suppressed.

[0028] The sulfonate salt used as the copolymer component is preferably sodium sulfonate. Furthermore, when the copolymer component is a sodium salt as described above, the sodium can be supplied by sodium hydroxide, which is used as an alkali during saponification.

[0029] When using a resin with a polyvinyl alcohol backbone as layer X, it is preferable that layer X does not contain acrylic resin or polyester resin with adhesive properties, or resins with crosslinking properties such as melamine or oxazoline that improve film-forming properties. Resins with adhesive properties or crosslinking properties interact with the hydroxyl groups of the side chains of the resin with a polyvinyl alcohol backbone, making it difficult to set |HX(1)-HX(20)| in a preferred range.

[0030] The crystallinity of layer X of the laminated polyester film of the present invention is preferably 14% or more and 40% or less, more preferably 15% or more and 40% or less, and even more preferably greater than 31% and 40% or less. Crystallinity generally indicates the degree of crystallization of a substance. The higher the crystallinity, the more free energy-stable crystalline parts the substance contains. That is, the higher the crystallinity, the more stable the substance itself. If the crystallinity is set to 15% or more, the solvent resistance can be good. In addition, if the crystallinity is set to 40% or less, the washability can be better. In addition, |HX(1)-HX(20)| can also be set to a preferred range. In addition, by setting the copolymerization amount or degree of polymerization and degree of saponification to the preferred range, the crystallinity of layer X can be set to the range.

[0031] Furthermore, the crystallinity of layer X is set to be determined using the method described in the embodiments.

[0032] A preferred embodiment of the laminated polyester film of the present invention is a laminated polyester film having a polyester film and a layer X, wherein the thickness xa (nm) of the layer X and the roughness RzjisB (nm) of the surface of the polyester film opposite to the surface (surface B) having the layer X satisfy the following condition: Condition: 0.2 ≤ RzjisB / xa ≤ 20.0 From the viewpoint of simpler structure and higher productivity, a more preferred embodiment is one where the surface of the opposite side (surface B) is the surface (surface B) of the polyester film opposite to the surface (surface A) having the layer X. Furthermore, from the viewpoint of improved washability, embodiments where the layer X satisfies the aforementioned performance, or embodiments where the layer X exhibits hydrophilicity, are listed as more preferred embodiments different from the above. Furthermore, the statement that layer X exhibits hydrophilicity means that the surface free energy value is 10 mN / m or higher when measured using the method described in the examples. If layer X is not exposed, it is assumed that layer X is exposed by grinding until its thickness is 30% to 70% of the original layer X thickness, and the surface free energy of layer X is calculated.

[0033] When a membrane having layer X is stored in a humid and hot environment, especially when it is wound into a roll and surface pressure is applied, the properties of the membrane can sometimes change significantly, causing problems when using the membrane. By manufacturing a membrane having layer X and satisfying condition 3, this change in properties can be significantly suppressed. This will be explained in detail below.

[0034] When the laminated polyester film of the present invention is wound in a roll shape, the surface of the layer X and the surface of the polyester film opposite to the surface (surface B) having the layer X (surface A) are in contact. RzjisB is the 10-point average roughness measured using the method described in the embodiments. The larger the value, the greater the surface unevenness. When the value of RzjisB / xa is small and less than 0.2, that is, when RzjisB is small or the value of xa is large, or both, sometimes when surface pressure is applied in a roll shape, layer X tends to adhere closely to the surface of the B side in a humid and hot environment, and layer X is transferred to the surface of the B side. In addition, when the shape of layer X changes, the washability of layer X may sometimes decrease, or when another layer is coated in contact with layer X, the coatability or function of that layer may sometimes decrease.

[0035] When the value of RzjisB / xa is large and exceeds 20.0, that is, when RzjisB is large or the value of xa is small, or both, sometimes when surface pressure is applied in a roll shape, the shape of layer X changes according to the unevenness of the B-side surface itself in a humid and hot environment, and the washability of layer X decreases. In addition, when another layer is coated in contact with layer X, the coatability or function of that layer sometimes decreases. For the same reason, the value of RzjisB / xa is preferably 1.0 or more and 10.0 or less, more preferably 1.5 or more and 10.0 or less, and particularly preferably 3.0 or more and 8.5 or less.

[0036] Preferably, the thickness xa (nm) of the layer X and the surface roughness RzjisX (nm) of the layer X in the laminated polyester film of the present invention satisfy the following condition 7. Condition 7: 0.01 ≤ RzjisX / xa ≤ 3.0. RzjisX refers to the surface roughness RzjisX of layer X, which is the 10-point average roughness measured using the method described in the embodiments. In the case of a bilayer structure consisting of layer X and a polyester film, RzjisX represents the roughness of the surface of layer X opposite to the surface in contact with the polyester film. The roughness of layer X is affected by the roughness of surface A of the polyester film. By setting RzjisX / xa to 3.0 or less, layer X can cover surface A entirely, which can improve the hydrophilicity of layer X. In addition, when other layers are coated in contact with layer X, the coatability or function of that layer can be fully demonstrated.

[0037] By setting RzjisX / xa to 0.01 or higher, the membrane's processability can be improved. From the same point of view, RzjisX / xa is preferably 0.5 or higher and 1.5 or lower.

[0038] In the laminated polyester film of the present invention, the thickness xa of layer X is preferably 10 nm or more and 500 nm or less. By setting xa to 10 nm or more, conditions 3 and 7 are easily satisfied, thus increasing productivity. In addition, by setting xa to 500 nm or less, when layer X is formed by coating, good coatability can be achieved.

[0039] As a preferred embodiment of the laminated polyester film of the present invention, a laminated polyester film having at least one surface layer having a layer Y satisfying the following formula can be cited. Among them, from the viewpoint of further improving washability, a laminated polyester film having a layer Y, a layer X, and a polyester film satisfying the following formula in sequence can be cited as a further preferred embodiment, and a laminated polyester film having a layer Y satisfying the following condition on the side opposite to the surface of the layer X and the surface in contact with the polyester film can be cited as a particularly preferred embodiment. 80≦HY(1)≦120、1≦|HY(1)-HY(20)|≦90 HY(1) (°): Contact angle of water after 1 second after contact with layer Y HY(20) (°): Contact angle of water after 20 seconds after contact with layer Y By controlling the contact angle with water and having a layer Y with HY(1) set to the range, the surface energy of layer Y can be reduced, and as a result, the laminated polyester film having layer Y can be used as a release film.

[0040] That is, by controlling the contact angle with water and setting it to 80°≦HY(1), the release property can be sufficiently high, and the laminated polyester film with layer Y can be better used as a release film. In addition, by setting HY(1)≦120, it is difficult for the coating used to form the release layer to bounce off when the release layer is set by coating, and coating defects such as pinholes in the release layer can be prevented. From the same point of view, HY(1) is preferably 85° or higher and 110° or lower.

[0041] In addition, HY (20) changes compared to HY (1), and |HY (1)-HY (20)| is set as the range, thereby allowing the physical properties of layer Y to change using water as a medium. That is, by changing the physical properties using water as a medium, the adhesion between layer Y and the laminated polyester film changes, thereby making it easy to remove layer Y using water from the laminated polyester film.

[0042] The setting of 1≦|HY(1)-HY(20)| means that layer Y gradually permeates with water. By setting it to 1≦|HY(1)-HY(20)|, a large amount of water permeates to the polyester film side as the substrate, so it is easy to peel off from other layers on the surface of the substrate. Layer Y can be removed by water self-deposition polyester film, which is easy to recycle. From the same point of view, it is better to set it to 5≦|HY(1)-HY(20)|. In addition, by setting it to |HY(1)-HY(20)|≦90, the physical properties of layer Y are stable, and the deterioration of layer Y due to water vapor, etc. can be suppressed. In addition, by setting it to |HY(1)-HY(20)|≦30, it is easy to form other layers on layer Y, or it can suppress the local deterioration of washability due to the modification or segregation of layer Y when other layers are formed on layer Y, which is better. For the same viewpoint, |HY(1)-HY(20)| is preferably 5° or more and 25° or less. In addition, for the same viewpoint, it is preferable that HY(1)-HY(20)≧0.

[0043] In order to set the |HY(1)-HY(20)| of layer Y within the preferred range, the following methods are listed as preferred embodiments: a method of making layer Y contain the resin and surfactant described later; or a method of forming a laminated polyester film in which layer X of a polyester film has a polar component γXP with a surface free energy of 20 mN / m or more and 30 mN / m or less on at least one side and a hydrogen bond component γXH with a surface free energy of 6.0 mN / m or more and 10 mN / m or less on the side opposite to the side of layer X and the side in contact with the polyester film.

[0044] If layer X and layer Y are in contact with each other and the surface free energy is within the range, then in order to promote the permeation of water in contact with layer Y, |HY(1)-HY(20)| can be increased. The higher the water repellency of layer Y, the higher the water permeability of layer Y, and the more |HY(1)-HY(20)| can be increased.

[0045] The resin used in layer Y of a laminated polyester film comprising a substrate / layer Y structure is preferably selected from one or more compounds selected from silicone compounds having a dimethylsiloxane backbone, compounds having long-chain alkyl groups, compounds having a polyolefin backbone, perfluoroalkyl groups, and other fluorinated compounds. Among these, compounds having a polyolefin backbone are preferably used. Compounds with a polyolefin backbone tend to have good compatibility with the surfactants described later, so it is easy to set |HY(1)-HY(20)| in the range described above. Examples of compounds having a polyolefin backbone include polymers or copolymers of one or more of polyethylene, polypropylene, polybutadiene, hydrogenated polybutadiene, polyisoprene, hydrogenated polyisoprene, polyisobutylene, and α-olefins. α-olefins refer to olefins having a double bond at a single end of their molecular chain, such as 1-octene.

[0046] When a compound with a polyolefin backbone is used in layer Y of a laminated polyester film comprising a substrate / layer Y, layer Y preferably contains a surfactant. By setting it to the aforementioned state, water permeating layer Y can easily diffuse to the substrate side surface, and is preferably set to 1≦|HY(1)-HY(20)|. The amount of surfactant added relative to 100 parts by mass of the compound with the polyolefin backbone is preferably 0.5 parts by mass or more and 4 parts by mass or less, more preferably 1 part by mass or more and 2 parts by mass or less. If the amount of surfactant is 0.5 parts by mass or more, the surfactant becomes an amount sufficient to diffuse into the entire layer Y, and water easily permeates layer Y. When the amount of surfactant added exceeds 4 parts by mass, the surfactant accumulates on the surface of layer Y, and may sometimes contaminate the molded material.

[0047] Examples of surfactants that can be used in layer Y of a laminated polyester film containing a substrate / layer Y include various nonionic surfactants, such as polyoxyethylene lauryl ether, polyoxyethylene hexadecyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, and other polyoxyethylene alkyl ethers; polyoxyethylene octylphenyl ether, polyoxyethylene nonylphenyl ether, and other polyoxyethylene alkylphenyl ethers; polyoxyethylene monolaurate, polyoxyethylene monostearate, polyoxyethylene monooleate, and other polyoxyethylene fatty acid esters; sorbitol monolaurate... Sorbitol fatty acid esters, including sorbitol monopalmitate, sorbitol monostearate, and sorbitol monooleate; polyoxyethylene sorbitol fatty acid esters, including polyoxyethylene sorbitol monolaurate, polyoxyethylene sorbitol monopalmitate, polyoxyethylene sorbitol monostearate, polyoxyethylene sorbitol tristearate, polyoxyethylene sorbitol triisostearate, polyoxyethylene sorbitol monooleate, and polyoxyethylene sorbitol trioleate; polyoxyethylene glycerol ether fatty acid esters; and polyoxyethylene-polyoxypropylene block copolymers. These nonionic surfactants can be used alone or in combination of two or more.

[0048] Examples of highly water-repellent resins that can be used in layer Y of a laminated polyester film having a substrate, layer X, and layer Y include: silicone compounds having a dimethylsiloxane backbone, compounds having long-chain alkyl groups, and compounds having fluorine. Among these, silicone (organic polysiloxane) with a dimethylsiloxane backbone that has high water permeability is preferred, and resins having a curable silicone backbone are particularly preferred. Resins with a curable silicone backbone include: "addition reaction type," in which organohydrogen polysiloxanes and alkenyl-containing organosiloxanes are heat-cured using a platinum catalyst; "condensation reaction type," in which organohydrogen polysiloxanes and hydroxyl-terminated organosiloxanes are heat-cured using an organotin catalyst; "UV-curing type," in which photopolymerization initiators are formulated into organosiloxanes containing acrylonitrile or methacrylonitrile, or into alkenylonitrile and mercaptoonitrile, and then cured by UV light irradiation; and "cationic polymerization type," in which epoxy groups are photo-ring-opened using onium salt initiators for curing. Any of these types can be used, but from the viewpoint of productivity and peel strength, addition reaction type or UV-curing type are preferred.

[0049] Specific examples of resins having an addition-reaction type silicone backbone are preferably those containing polydimethylsiloxane and hydrosiloxane with vinyl groups at the ends, such as: KS-847, KS-847T, KS-841, KS-774, KS-3703T, X-62-2825 manufactured by Shin-Etsu Chemical Co., Ltd., and SD7333, SRX357, SRX345, LTC310, LTC303E, LTC300B, LTC350G, LTC750A, LTC851, LTC759, LTC755, LTC761, LTC856, etc. manufactured by Dow Toray Industries, Ltd. (Furthermore, "LTC" is a registered trademark).

[0050] As a specific example of a resin and catalyst having a condensation reaction type silicone backbone, it is preferred to include polydimethylsiloxane and hydrosiloxane with hydroxyl groups at the end and organotin catalysts, such as SRX290 or SY LOFF23 manufactured by Dow Toray Industries, Ltd.

[0051] As specific examples of resins and catalysts having a UV-curable silicone backbone, it is preferable that they contain an organic polysiloxane containing acrylonitrile or methacrylonitrile and a photopolymerization initiator, or contain a polydimethylsiloxane containing alkenyl and a polydimethylsiloxane containing mercapto and a photopolymerization initiator. Examples include FM-0711, FM-0721, FM-0725, FM-7711, FM-7721, FM-7725 manufactured by JNC Corporation, and BY24-510H and BY24-544 manufactured by Dow Toray Industries, Ltd.

[0052] As specific examples of resins and catalysts having a cationic polymeric silicone backbone, those comprising an epoxy-containing silicone and an onium salt initiator are preferred, such as TPR6501, UV9300 and XS56-A2775 manufactured by Momentive Performance Materials Japan.

[0053] In addition, the solvent durability of the surface of layer Y of the laminated polyester film of the present invention is preferably 5% or more and 100% or less. More preferably 10% or more and 100% or less. The solvent durability refers to the value obtained by performing a wiping test on the surface of layer Y of the laminated polyester film using a solvent and dividing the peel force of the surface of layer Y by the peel force of the surface of layer Y after the wiping test. Details of the determination method will be described later. The higher the solvent durability, the higher the solvent resistance, which can suppress the deterioration of smoothness caused by subsequent steps or the deterioration of removability caused by water. The practical upper limit of the solvent durability is 100%. If a resin with high removability is used in order to improve reusability, the solvent durability tends to be lower. By setting |HY(1)-HY(20)| in the range and setting the solvent durability in the range, both good reusability and good solvent resistance can be achieved.

[0054] Furthermore, the hydrogen bonding component γYH of the surface free energy of layer Y in the laminated polyester film of the present invention is preferably 1.5 mN / m or more and 10 mN / m or less, more preferably 1.5 mN / m or more and 5.0 mN / m or less. By setting γYH within this range, layer Y is easily permeable to water. Therefore, when washing with water, not only is the removability of layer Y good, but the layer formed on the substrate can also be easily removed by peeling it off from the side closer to the substrate surface by water permeating layer Y. Especially when layer X is also present, layer X can be removed more actively by water permeating layer Y, and layers X and Y can be easily removed from the laminated polyester film.

[0055] The laminated polyester film of the present invention, by flexibly utilizing the aforementioned characteristics, is preferably used for demolding applications where a release layer is provided on the side of layer Y opposite to the side in contact with layer X or the substrate, and the release layer is peeled off from layer Y. Furthermore, the laminated polyester film of the present invention allows layer X or layer Y to be removed by water, thus, after peeling off the demolded object, layer X or layer Y can be removed, yielding a high-purity polyester film. Furthermore, it is preferable that the laminated polyester film of the present invention, after removing layer X or layer Y, yields a high-purity polyester film for reuse. Moreover, it is even more preferable that after removing layer X or layer Y, only the polyester film is removed and reused. As a method of reuse, examples include the method of re-providing layer X or layer Y on the removed polyester film for use as a demolding film, or the method of remelting the polyester film and re-forming it into a polyester film. Regarding the method of remelting and re-forming into a polyester film, the reuse application is not limited and can be used for various applications, which can greatly contribute to reducing environmental impact, and is therefore preferred.

[0056] When using silicone compounds, especially compounds containing dimethylsiloxane bonds, as layer Y of the laminated polyester film of the present invention, if the component containing dimethylsiloxane bonds is mixed with the polyester film and remelted, it may sometimes become a foreign object and promote the deterioration of the polyester, or it may be impossible to extrude after melting. Therefore, in order to remelt and reuse the film of the present invention, it is preferable to remove layer Y.

[0057] When using the laminated polyester film of the present invention having layer X or layer Y as a release film, the release layer may be, for example, an organic adhesive mainly composed of acrylic acid, or a sheet of inorganic material mainly composed of metal or metal oxide. In particular, barium titanate, a metal oxide, is essential for the manufacture of MLCCs, and the amount of release film used in the step of manufacturing barium titanate sheets increases. In this case, by using the laminated polyester film of the present invention having layer X or layer Y in the step of manufacturing barium titanate sheets, layer X or layer Y can be removed from the laminated polyester film of the present invention after use in the step of manufacturing barium titanate sheets, resulting in a high-purity polyester film that can be reused, thereby greatly contributing to the reduction of environmental impact.

[0058] The following describes a method for manufacturing the laminated polyester film of the present invention, but the present invention is not limited to the laminated polyester film obtained by this method.

[0059] The polyester film of the laminated polyester film of the present invention can be produced by heating and melting dried raw materials in an extruder as needed, extruding them from a die onto a cooled casting drum, and processing them into a sheet (melt casting method). Preferably, the sheet is produced by electrostatic close-contact cooling and solidification on a drum cooled to a surface temperature of 20°C or higher and 60°C or lower, thus creating an unstretched sheet. More preferably, the temperature of the casting drum is 20°C or higher and 40°C or lower, and even more preferably 20°C or higher and 30°C or lower.

[0060] Preferably, the unstretched sheet is then biaxially stretched at a temperature T1n (°C) that satisfies the following formula (i) to a length of 3.6 times or more in the long side direction (MD) of the film, a width direction (TD) of 3.9 times or more in the film, and an area ratio of 14.0 times or more and 20.0 times or less.

[0061] The stretching ratio in the width direction of the film is preferably 4.0 times or more, more preferably 4.3 times or more and 5.0 times or less. By setting the stretching ratio in the width direction of the film to 4.0 times or more, when layer X is coated onto the uniaxially stretched film using the inline coating method described later, the components constituting layer X are stretched and elongated along with the film, thus suppressing the regular arrangement of the components constituting layer X and setting the crystallinity of layer X to a better range. If the stretching ratio in the width direction exceeds 5.0 times, the film-forming properties of the film may sometimes decrease. (i) Tg (°C) ≦ T1n (°C) ≦ Tg+40 (°C) Tg: Glass transition temperature of polyester film (°C) The stretching method in the long side direction of the film can preferably use a method that utilizes the speed difference between rollers. In this case, in order to prevent the film from slipping, it is also a better implementation method to fix the film with clamping rollers while stretching in multiple sections.

[0062] Preferably, the biaxially stretched film is then subjected to heat-fixing treatment for 1 second to 30 seconds at a temperature (Th0 (°C)) that satisfies the following formula (ii), and then cooled to room temperature after uniform slow cooling to obtain a polyester film. (ii) Tmf-35 (°C) ≦ Th0 (°C) ≦ Tmf (°C) Tmf: melting point of the film (°C) By obtaining a biaxially stretched film using the conditions that satisfy (ii), the film can be given appropriate orientation, improving its processability when used as a release film.

[0063] In the laminated polyester film of the present invention, in addition to the manufacturing method described above, in order to set conditions 3 and 7 within the aforementioned range, it is preferable that the film contains particles. The particles contained are preferably spherical particles with a uniform particle size distribution, such as colloidal silica particles, cross-linked polystyrene particles, or calcium carbonate particles. The particle content is preferably 0.01% by mass or more and 3.0% by mass or less relative to the mass of the polyester film. Furthermore, the particle size is preferably 50 nm or more and 5000 nm or less. To satisfy condition 6, the particle size is 100 nm or more and 5000 nm or less, and more preferably 300 nm or more and 2000 nm or less. To satisfy condition 7, the particle size is 50 nm or more and 1000 nm or less, and more preferably 50 nm or more and 400 nm or less. Regarding the polyester film of the present invention, in order to set conditions 6 and 7 to preferred ranges, the sheet extruded onto the casting drum is preferably a laminated structure of two or more layers, and more preferably a laminated structure of three or more layers having an intermediate layer (C layer) between the layer constituting side A (layer A) and the layer constituting side B (layer B). In particular, when there is an intermediate layer (C layer) between layer A and layer B, recycled raw materials using the method described later can be used in layer C, which is therefore preferred.

[0064] Next, the method of providing layers X and Y on the polyester film of the laminated polyester film of the present invention will be described below, but the present invention is not limited to the film obtained by this method.

[0065] In the case where layer X is formed from a resin that readily absorbs water, a method of dissolving the resin forming layer X in water and coating it onto the polyester film of the present invention is preferred. As a coating method, conventional coating methods such as gravure coating, Meyer bar coating, air knife coating, and blade coating can be used. In particular, from the viewpoint of controlling the crystallinity of layer X, an in-line coating method is preferred, wherein the resin that forms the basis of layer X is coated onto the surface of a polyester film uniaxially stretched along its long side direction, and layer X is formed while the polyester film is stretched along its width direction. The thickness of layer X is preferably 10 nm or more and 500 nm or less. By setting it to 10 nm or more, the water absorption of layer X can be fully manifested, resulting in good removability. Furthermore, by setting it to 500 nm or less, the occurrence of blocking and reduced processability can be suppressed. From the same viewpoint, it is more preferably 50 nm or more and 200 nm or less.

[0066] Next, the method for setting layer Y will be described. Layer Y can be set simultaneously with layer X or separately. When set simultaneously, methods such as coating both layers simultaneously using a mold or the like, or coating using a coating agent that pre-mixes the components of layer X and layer Y, can be listed. In order to improve the lamination accuracy of layer X and layer Y, when setting layer X and layer Y, it is preferable to set layer X and layer Y separately. A coating liquid that dissolves the components of layer Y can be used and coated onto the laminated polyester film containing layer X obtained by the method using a common coating method such as gravure coating, Mayer rod coating, air knife coating, or doctor blade coating. The thickness of layer Y is preferably 10 nm or more and 1000 nm or less. By setting it to 10 nm or more, the function of layer Y can be fully displayed, and by setting it to 1000 nm or less, the water permeability of layer Y can be fully displayed, making it easy to set |HY(1)-HY(20)| in a preferred range. From the same perspective, it is better to be above 50 nm and below 500 nm.

[0067] Next, the method for removing layers X and Y will be described. Layer X has the aforementioned characteristics, therefore, cleaning with water is a preferred embodiment. For example, the preferred method for removing layers X and Y is to provide the laminated polyester film comprising layers X and Y of the present invention to a step of winding up the laminated polyester film, a step of supplying warm water to the surface of the wound-up laminated polyester film and peeling off the surface laminated portions (layers X and Y) from the laminated polyester film, and a step of winding up the peeled polyester film. The temperature of the warm water is preferably 50°C or higher and 120°C or lower. By setting it to 50°C or higher, sufficient cleaning performance can be obtained. By setting it to 120°C or lower, the situation where the film cannot be transported due to exceeding the glass transfer temperature of the polyester film can be suppressed. The contact time between the water and the surface of the laminated polyester film is preferably 5 seconds or higher, more preferably 10 seconds or higher, and even more preferably 30 seconds or higher and 600 seconds or lower. The step of providing warm water to the surface of the rolled-out laminated polyester film can be performed in a water bath, covering the entire laminated polyester film, or by pressurizing heated water and spraying it onto the laminated polyester film. By supplying water to layer Y of the laminated polyester film, the water permeates through layer Y and is absorbed on the side of layer X or the substrate, causing a change in the physical properties of layer Y. As a result, layer Y is easier to peel off from the laminated polyester film, improving cleanability. In the above steps, the speed of transporting the laminated polyester film is 5 m / min or more, preferably 10 m / min or more, more preferably 20 m / min or more and 100 m / min or less. In the step of removing layers X and Y, applying tension to the laminated polyester film while transporting the laminated polyester film with layers X and Y is also a preferred example. By applying tension, the surface of the laminated polyester film is stretched, improving the peelability of layers X and Y, thereby improving cleanability. The tension is preferably 5 N / m or more and 100 N / m or less, more preferably 20 N / m or more and 80 N / m or less, and even more preferably 30 N / m or more and 50 N / m or less. By setting the tension to 5 N / m or more, the surface of the laminated polyester film is sufficiently stretched, resulting in good cleanability. Furthermore, by setting the tension to 100 N / m or less, wrinkles in the film and reduced surface stretchability can be suppressed, further improving cleanability.

[0068] Next, a preferred embodiment of a method for using a film from which layers X and Y have been removed as recycled raw material will be described. Preferably, the method involves: feeding a film roller from which layers X or Y have been removed using the method into a pulverizer having a rotating blade driven by a motor for pulverization, then feeding it into an extruder for melting, extruding it into a filament, and cutting it into pellets to obtain recycled raw material. To set the inherent viscosity of the recycled raw material within a preferred range, the melting temperature is preferably 250°C or higher and 300°C or lower. Furthermore, the extruder may have a single-screw or twin-screw screw. Since the film from which layers X or Y have been removed sometimes contains particles, or sometimes contains residue from the removal of layers X or Y, from the viewpoint of uniformly mixing the contained components, a twin-screw extruder is preferred. Additionally, during melt extrusion, to set the components other than polyester within an appropriate range, filtration using a filter is also preferred. The resulting recycled materials can be used as raw materials for layers A, B, and C.

[0069] Preferably, the obtained recycled raw material contains 0.0001% by mass or more and 0.3% by mass or less of components other than polyester. If the content of components other than polyester exceeds 0.3% by mass, depending on the manufacturing apparatus, a large amount of foreign matter is generated when the film is formed using recycled raw material, making it difficult to obtain the desired characteristics. For example, when the recycled raw material is used in layer A or layer B of the laminated film of the present invention, the surface characteristics of layer A or layer B may not be satisfied. If it is desired to reduce the amount of impurities to less than 0.0001% by mass of polyester, the damage to the substrate film caused by the step of removing layer X or layer Y becomes greater, and it may be difficult to obtain recycled polyester.

[0070] Recycled materials can be used in any of layers A, B, and C, but are preferably used in layer C. Recycled materials sometimes contain particles from the laminated film as components other than polyester; therefore, using recycled materials in layer A or layer B may sometimes affect the surface properties of layer A or B. On the other hand, when used in the intermediate layer between layers A and B, i.e., layer C, layer C does not have a surface, so even when using recycled materials, the surface properties will not be impaired, which is therefore preferable.

[0071] As a preferred embodiment of the laminated polyester film of the present invention, as described above, after providing layer X on at least one side of the polyester film, layer Y is provided and used as a release film or other functional laminated film for a step. Layer X and layer Y are then washed and removed by water, thereby obtaining a polyester film with high purity. Therefore, the obtained polyester film can be directly reused, or the film can be remelted and wafered for use as a recycled raw material in film production, and reused as a film. From the viewpoint of film-forming properties, the intrinsic viscosity (IV) of the recycled raw material is 0.5 or more and 0.7 or less, preferably 0.55 or more and 0.65 or less.

[0072] [Evaluation Method of Properties] A. Thickness of Each Layer The thickness of each layer of the laminated film is determined using the following method. A cross-section of the film is cut out in a direction parallel to the width direction using a slicer. The cross-section is observed at 5000x magnification using a scanning electron microscope, and the thickness of each layer of the laminated film is measured.

[0073] B. Intrinsic Viscosity (IV) The polyester film of the present invention was dissolved in 100 ml of o-chlorophenol (solution concentration C = 1.2 g / dl), and the viscosity of the solution at 25°C was measured using an Ostwald viscometer. In addition, the viscosity of the solvent was measured in the same way. Using the obtained solution viscosity and solvent viscosity, [η] (dl / g) was calculated by the following formula (a), and the obtained value was set as the intrinsic viscosity (IV). (a) ηsp / C = [η] + K[η]2·C (Here, ηsp = (solution viscosity (dl / g) / solvent viscosity (dl / g)) - 1, K is the Huggins constant (set to 0.343)).

[0074] B-2. Amount of terminal carboxyl groups The amount of terminal carboxyl groups (COOH terminal group amount) is determined by the method described in International Publication No. 2010 / 103945.

[0075] C. Compositional Analysis of Layer X: Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) and Fourier Transform Infrared Spectroscopy (FT-IR) spectra of layer X were determined to analyze the presence or absence of a polyvinyl alcohol backbone, etc. [TOF-SIMS Measurement Conditions] For the surface of layer X, the TOF-SIMS spectrum was measured using the following apparatus. Apparatus: TOF.SIMS5 manufactured by ION-TOF Corporation. Primary ion species: Bi3++. Primary ion accelerating voltage: 25 kV. Pulse width: 125 ns. Perforation: None (for high spatial decomposition energy measurement). Grating size: 40 μm × 40 μm. Number of scans: 64. Secondary ion polarity: Positively charged. Neutralization: Yes. Post-acceleration voltage: 9.5 kV. [FT-IR Measurement Conditions] For the surface of layer X, the FT-IR spectrum was measured using the following apparatus. Apparatus: Spectrum 100 manufactured by PerkinElmer; Light source: Special ceramic detector: DTGS; Decomposition energy: 4 cm⁻¹; Number of measurements: 256; Measurement frequency range: 4,000 cm⁻¹ to 680 cm⁻¹; Measurement mode: Attenuated total reflection (ATR) method; Auxiliary device: Single-reflection ATR crystal (material: diamond / ZnSe).

[0076] Copolymer content (mol%) of layer X (C-2) The copolymer content (mol%) was determined using the following apparatus in 13C nuclear magnetic resonance (NMR) and DEPT135 spectra based on the peak area of ​​the carbon signal with the introduced modified group. Apparatus: ECZ-600R (manufactured by JEOL RESONANCE Co., Ltd.) Measurement method: Single 13C pulse with inverse gated 1H decoupling Measurement frequency: 150.9 MHz Pulse width: 5.25 μs Locking solvent: D2O Chemical shift reference: TSP (0 ppm) Number of cycles: 10,000 Measurement temperature: 20℃ Sample rotation speed: 15 Hz.

[0077] D. The degree of saponification of layer X is calculated by titrating the amount of acetic acid groups in the sample using a titration method based on sodium hydroxide aqueous solution, according to JIS K 6726 (1994) test method for polyvinyl alcohol.

[0078] E. The average degree of polymerization of layer X is determined according to JIS K 6726 (1994) test method for polyvinyl alcohol. After the sample is completely saponified in an aqueous sodium hydroxide solution, the viscosity at 25°C is measured using an Oswald viscometer, and the average degree of polymerization is calculated based on the limiting viscosity.

[0079] The surface free energy of layer X was measured using a contact angle meter DM501 manufactured by Kyowa Interface Science Co., Ltd. and the accompanying analytical software FAMAS, by the following method. Glycerol, ethylene glycol, methylamine, and diiodomethane were used as standard solutions relative to the surface of layer X. The static contact angles of each liquid at 25°C were determined. The static contact angles of each liquid, along with the dispersion components, polar components, and hydrogen bond components of the surface free energy of each liquid as described in Non-Patent Document 1, were imported into the "Extended Hawkes Formula of Hata and Kitasaki" described in Non-Patent Document 2. The simultaneous equations were solved to determine the dispersion components, polar components, and hydrogen bond components of the surface free energy of layer X.

[0080] Regarding the determination of the static contact angle, the sample was placed in an environment of 25°C for 12 hours beforehand. The contact time of the droplet with the sample surface was set to 0 seconds. Using the image taken after 30 seconds, the static contact angle was calculated using the θ / 2 method. The measurement was performed 5 times at different positions. Using the average value of the static contact angle, the dispersion component, polar component, and hydrogen bond component of the surface free energy of layer X were calculated.

[0081] G. The surface free energy of layer Y was determined using the same method as that of layer X, except that benzyl alcohol, ethylene glycol, methylamine and diiodomethane were used as standard solutions.

[0082] H. Contact Angle of Water (°) The contact angle was measured using a contact angle meter DM501 manufactured by Kyowa Interface Science Co., Ltd. and the accompanying analysis software FAMAS. The following method was used. The contact time of the water droplet with the sample surface was set to 0 seconds in an environment of 23°C and 65%RH. An animation of the shape of the water droplet was recorded for 20 seconds. The measurement was performed 5 times with different positions. When the sample surface in contact with the water droplet was layer X, the average contact angles calculated based on the shape of the water droplet after 1 second and the shape of the water droplet after 20 seconds were calculated as HX (1) and HX (20), respectively. When the sample surface in contact with the water droplet was layer Y, the average contact angles were calculated as HY (1) and HY (20), respectively.

[0083] H-2. The crystallinity of layer X was determined by measuring the spectrum of the laminated polyester film on the side of layer X using the ATR method of FT-IR under the following apparatus and conditions, and then dividing it by the spectrum of the polyester film "Lumirror" (registered trademark) #50T60 manufactured by Toray Industries, Inc., which was measured in the same manner, to obtain the difference spectrum. Subsequently, with the minimum absorbance value between 1400 cm⁻¹ and 1550 cm⁻¹ as the baseline, the maximum absorbance value between 1400 cm⁻¹ and 1450 cm⁻¹ is set as c. With the line connecting the two minimum absorbance values ​​between 1100 cm⁻¹ and 1200 cm⁻¹ as the baseline, the maximum absorbance value between 1130 cm⁻¹ and 1150 cm⁻¹ is set as d. Based on the formula "Percent crystallinity = 92(d / c) - 18" described in the non-patent literature ("J. Polymer Science": Part A-1, Vol.4, pp.679-698 (1966)), the crystallinity of layer X is calculated. Furthermore, in the calculation of c and d, if there are two or more maximum absorbance values ​​in the corresponding frequency range, the larger absorbance value is used to calculate c and d. Additionally, if there are three or more minimum absorbance values ​​between 1100 cm⁻¹ and 1200 cm⁻¹, the two with the lowest absorbance are used to determine the baseline. Furthermore, in the X-side of the laminated polyester film, layer X can be the outermost surface, and layer Y can also be the outermost surface. Apparatus: 670-IR (FT-IR manufactured by Varian) Light source: Silicon carbide incandescent rod Detector: DLatgs (deuterated L-alanine-doped triglycine sulfate) Decomposition energy: 4 cm⁻¹ Number of measurements: 256 Measurement method: Attenuated total internal reflection method Auxiliary device: Single-reflection ATR measurement auxiliary device (The Seagull™) ATR crystallization; germanium incident angle: 60° Polarized light: None.

[0084] I. Solvent durability (%) The following method was used to determine the solvent durability using a vibration type testing machine manufactured by Daiei Scientific & Precision Machinery Co., Ltd. (according to JIS L 0849 (2013)). [Wiping treatment using solvent impregnated cloth] The Y-layer surface of the film was wiped using the following testing machine and friction element. Testing machine: Vibration testing machine (JIS L 0849 (2013) Type II friction testing machine) Friction component: Toluene and ethanol mixed solvent (mass ratio 1:1) impregnated in cotton cloth (wide fine cotton cloth No. 3) Load: 1.0 kg Number of cycles: 30 cycles [peeling treatment] The polyester adhesive tape (No. 31B manufactured by Nitto Denko Co., Ltd., 19 mm wide) was pressed and attached to the wiped part of the surface of layer Y using a 2.0 kg roller. After standing for 24 hours at 23°C and 65%RH, the peeling force between the sample surface and the polyester adhesive tape was measured using a peeling tester VPA-H200 manufactured by Kyowa Interface Science Co., Ltd. at a peeling angle of 180° and a peeling speed of 300 mm / min. The force was converted to a width of 50 mm and F(B) was calculated. The peel force F(A) of the Y-layer surface before wiping was also determined using the same method. Solvent durability was determined based on the following formula: Solvent durability (%) = F(A) / F(B) × 100 J. Peelability of the demolded material: Polyester adhesive tape (No. 31B, 19 mm wide, manufactured by Nitto Denko Co., Ltd.) was attached to the surface of the demolded material of the laminated polyester. The strength was determined using a peel testing machine VPA-H200 manufactured by Kyowa Interface Science Co., Ltd., with a peel angle of 180° and a peel speed of 300 mm / min, and converted to a width of 50 mm.

[0085] K. Solvent resistance as an indicator of haze change: After the self-laminated polyester with a demolding material is peeled off, the haze Hz (B) is measured using a haze meter NDH-5000 manufactured by Nippon Denshoku Co., Ltd., based on JIS K 7136 (2000). The haze Hz (A) of the laminated polyester before the demolding material is laminated is also measured using the same method, and ΔHz is calculated based on the following formula. ΔHz = Hz (B) - Hz (A) L. Solvent resistance as an indicator of surface roughness change: Using a non-contact surface shape measurement system "VertScan" (registered trademark) R550H-M100 manufactured by Mitsubishi Kagaki Systems Co., Ltd., the surface roughness Sa (A) of the laminated polyester before the demolding material is laminated and the surface roughness Sa (B) of the laminated polyester after the demolding material is peeled off are measured under the following conditions, and ΔSa is calculated based on the following formula. Surface roughness was calculated as the arithmetic mean of five measurements. ΔSa = Sa(B) - Sa(A) (Measurement conditions) • Measurement mode: Wave mode. • Objective lens: 50x. • 0.5× Tube lens. • Measurement area: 187 μm × 139 μm.

[0086] The evaluation of the removability of M. layers X and Y is performed by measuring the water contact angle obtained after 1 second using the polyester film obtained after removing layers X and Y, as described in item H., and the following determination is made.

[0087] A: 65° or higher but less than 80° B: 80° or higher but less than 90° or less than 65° C: 90° or higher but less than 95°

[0088] D: 95° or higher but less than 98°.

[0089] E: above 98°.

[0090] N. Reusability: The polyester film after removing layers X and Y is pulverized, dried at 180°C for 2 hours, fed into an extruder, melt-extruded at 280°C, and then formed into a sheet on a casting drum cooled to 25°C. The intrinsic viscosity of the resulting sheet is determined using the method described in B. The smaller the difference (ΔIV) between this intrinsic viscosity IV(R) and the intrinsic viscosity IV of the polyester film, the better.

[0091] O.RzjisB, RzjisX (nm) The three-dimensional surface roughness of the sample was measured using the following apparatus and conditions. The ten-point average roughness Rzjis of the surface roughness was calculated using analysis software. The measurement was performed 10 times at different positions, and the average value was taken as RzjisB and RzjisX (nm). Apparatus: Surf-corder ET-4000A manufactured by Kosaka Research Institute Analysis software: i-Face model TDA31 Stylus tip radius: 0.2 μm Measurement field of view: X direction: 380 μm Spacing: 1 μm Y direction: 280 μm Spacing: 5 μm Needle pressure: 50 μN Measurement speed: 0.1 mm / s Cutoff value: Low frequency; 0.8 mm, high frequency; no leveling: whole area Filter: Gaussian filter (2D) Magnification: 100,000 times.

[0092] P. Amount of components other than polyester in the recycled raw material (mass%): A specified amount of sample was dissolved in o-chlorophenol at 160°C for 40 minutes and filtered using a glass filter (3G3). After filtration, the residue was washed with dichloromethane and dried with hot air at 130°C for 10 hours. The mass of the residue was calculated as (mass%) relative to the sample before dissolution.

[0093] Q. Removability of Layers X and Y after Humidity and Heat Treatment: The remaining portion of the laminated polyester film with layer X obtained by the method of each embodiment is wrapped in a moisture-proof packaging material (aluminum tube manufactured by Nagaoka Sangyo Co., Ltd.) in a roll shape and left to stand for 7 days at 60°C and 80% relative humidity. Then, the laminated polyester film with layer X is taken out, and coating agent A described later is applied to the side opposite to the side of layer X and the side in contact with the polyester film, with a thickness of 0.1 μm for layer Y, using a gravure coating method, thereby obtaining a laminated polyester film with layers X and Y. Furthermore, the laminated polyester film with layers X and Y thus prepared is used as a release film, and dielectric paste described later is applied to the side opposite to the side of layer Y and the side in contact with layer X using a die coating method with a dried thickness of 1.0 μm as the release material. Then, a release film roll is obtained for the step of demolding the dielectric and peeling off the demolded material from the obtained laminate. This film roll is fed into a washing apparatus equipped with a roll-out device and a take-up device, and washed with water at 60°C for 2 minutes under a tension of 100 N / m to remove layers X and Y. The removability of layers X and Y is evaluated on the polyester film after removing layers X and Y. [Example]

[0094] The following examples illustrate the present invention, but the present invention is not necessarily limited to these examples.

[0095] [Manufacturing of PET-1] Antimony trioxide and magnesium acetate tetrahydrate were used as catalysts to polymerize PET from terephthalic acid and ethylene glycol using conventional methods. The resulting melt-polymerized PET had a glass transfer temperature of 81°C, a melting point of 255°C, an intrinsic viscosity of 0.65, and a terminal carboxyl group content of 20 eq. / t.

[0096] [Manufacturing of MB-A] 80 parts by weight of PET-1 and 10 parts by weight (1 part by weight as cross-linked polystyrene particles) of 0.1 μm cross-linked polystyrene particles (styrene-acrylate copolymer) are supplied as a 10% by weight water slurry. The vent hole is kept at a reduced pressure of less than 1 kPa and the moisture is removed to obtain MB containing 1% by weight of cross-linked polystyrene particles. The glass transition temperature is 81°C, the melting point is 255°C, the intrinsic viscosity is 0.61, and the terminal carboxyl group content is 22 eq. / t.

[0097] [Production of MB-B] 80 parts by weight of PET-1 and calcium carbonate particles with a particle size of 1.0 μm are supplied. The venting is kept at a reduced pressure of less than 1 kPa and moisture is removed to obtain MB containing 1% by weight of the particles. The glass transfer temperature is 81°C, the melting point is 255°C, the intrinsic viscosity is 0.61, and the terminal carboxyl group content is 22 eq. / t.

[0098] [Manufacturing of MB-C] MB-C is obtained by using PET-1 and alumina silica particles with a particle size of 4.0 μm, containing 1.0% by mass of alumina silica particles relative to the total MB-C content, while maintaining a reduced pressure of less than 1 kPa at the venting holes, removing moisture and mixing. The glass transfer temperature is 81°C, the melting point is 255°C, the intrinsic viscosity is 0.61, and the terminal carboxyl group content is 22 eq. / t.

[0099] [Manufacturing of MB-D] A 10% by mass water slurry of PET-1 and cross-linked polystyrene particles (styrene-acrylate copolymer) with a particle size of 0.2 μm is fed into an extruder with venting holes, containing 2% by mass of cross-linked polystyrene particles relative to the total MB-D content. The mixture is kneaded while maintaining a reduced pressure of less than 1 kPa to remove moisture, thereby obtaining MB-D. The glass transition temperature is 81°C, the melting point is 255°C, the intrinsic viscosity is 0.61, and the terminal carboxyl group content is 22 eq. / t. [Manufacturing of PEN] A transesterification reaction is carried out using manganese acetate as a catalyst. After the transesterification reaction, antimony trioxide is used as a catalyst to obtain PEN from dimethyl 2,6-naphthalenedicarboxylate and ethylene glycol using conventional methods. Additionally, 0.1% of δ-crystalline alumina particles with a particle size of 0.1 μm are added during polymerization. The resulting PEN had a glass transition temperature of 124℃, a melting point of 265℃, an intrinsic viscosity of 0.62, and a terminal carboxyl group content of 25 eq. / t.

[0100] [Preparation of Coating A] Coating A was obtained by adjusting 100 parts by mass of addition-reaction silicone resin release agent (trade name KS-847T manufactured by Shin-Etsu Chemical Industry Co., Ltd.) and 1 part by mass of platinum catalyst (trade name CAT-PL-50T manufactured by Shin-Etsu Chemical Industry Co., Ltd.) with toluene as the solvent and the solid content being 1.5% by mass.

[0101] [Preparation of Coating B] Coating B was prepared by adjusting 100 parts by weight of condensation reaction type silicone resin release agent (trade name SRX290 manufactured by Dow Toray Corporation) and 6 parts by weight of hardener (trade name SRX242C manufactured by Dow Toray Corporation) with toluene as solvent and solid content of 1.5% by weight.

[0102] [Preparation of Coating C] Coating C was prepared by adjusting the following ingredients with toluene as the solvent and solid content as 1.5% by mass: 2 parts by mass of UV-curing silicone resin release agent (trade name FM-7721 manufactured by JNC Corporation), 100 parts by mass of 1,9-nonanediol diacrylate (trade name "Biscoat" (registered trademark) #260 manufactured by Osaka Organic Chemicals Co., Ltd.), and 2 parts by mass of photopolymerization initiator (trade name "OMNIRAD" (registered trademark) manufactured by IGM Resins Co., Ltd.).

[0103] [Preparation of Coating D] Referring to Japanese Patent Application Publication No. 9-227627, a PVA with a saponification degree of 88, an average degree of polymerization of 500, and a copolymerization amount of sodium sulfonate of 0.1 mol% was prepared. The PVA was dissolved in water to obtain coating D at a mass percentage of 4%.

[0104] [Preparation of Coating E] Referring to Japanese Patent Application Publication No. 9-227627, a PVA with a saponification degree of 88, an average degree of polymerization of 500, and a copolymerization amount of sodium sulfonate of 0.5 mol% was prepared. The PVA was dissolved in water to obtain coating E at a mass percentage of 4%.

[0105] [Preparation of Coating F] Referring to Japanese Patent Application Publication No. 9-227627, a PVA with a saponification degree of 88, an average degree of polymerization of 500, and a copolymerization amount of sodium sulfonate of 1 mol% was prepared. The PVA was dissolved in water to obtain coating F at a mass percentage of 4%.

[0106] [Preparation of Coating G] Referring to Japanese Patent Application Publication No. 9-227627, a PVA with a saponification degree of 88, an average degree of polymerization of 400, and a copolymerization amount of sodium sulfonate of 3 mol% was prepared. The PVA was dissolved in water to obtain coating G at a mass percentage of 4%.

[0107] [Preparation of Coating H] Referring to Japanese Patent Application Publication No. 9-227627, a PVA with a saponification degree of 88, an average degree of polymerization of 300, and a copolymerization amount of 5 mol% sodium sulfonate was prepared. The PVA was dissolved in water to obtain coating H at a mass percentage of 4%.

[0108] [Preparation of Coating I] Referring to Japanese Patent Application Publication No. 9-227627, a PVA with a saponification degree of 88, an average degree of polymerization of 1000, and a copolymerization amount of sodium sulfonate of 1 mol% was prepared. The PVA was dissolved in water to obtain Coating I.

[0109] [Preparation of Coating J] Referring to Japanese Patent Application Publication No. 9-227627, a PVA with a saponification degree of 88, an average degree of polymerization of 300, and a copolymerization amount of sodium sulfonate of 1 mol% was prepared. The PVA was dissolved in water to obtain coating J.

[0110] [Preparation of Coating K] Polyvinyl alcohol "GL-05" (with a saponification degree of 88 and an average degree of polymerization of 500) manufactured by Mitsubishi Chemical Corporation was dissolved in water at a concentration of 4% by mass to obtain Coating K.

[0111] [Preparation of Coating L] Referring to Japanese Patent Application Publication No. 2008-291120, a PVA with a saponification degree of 88, an average degree of polymerization of 1000, and a copolymerization amount of sodium carboxylate of 1 mol% was prepared. The PVA was dissolved in water to obtain coating L at a mass percentage of 4%.

[0112] [Preparation of Coating M] Referring to Japanese Patent Application Publication No. 2004-285143, a PVA with a saponification degree of 88, an average degree of polymerization of 450, and a copolymerization amount of 1,2-ethylene glycol of 6 mol% was prepared. The PVA was dissolved in water to obtain coating M at a mass percentage of 4%.

[0113] [Preparation of Coating N] Referring to Japanese Patent Application Publication No. 9-227627, a PVA with a saponification degree of 98, an average degree of polymerization of 500, and a copolymerization amount of sodium sulfonate of 1 mol% was prepared. The PVA was dissolved in water to obtain coating N.

[0114] [Preparation of Coating O] Referring to Japanese Patent Application Publication No. 9-227627, a PVA with a saponification degree of 88, an average degree of polymerization of 2500, and a copolymerization amount of sodium sulfonate of 1 mol% was prepared. The PVA was dissolved in water to obtain coating O at a mass percentage of 4%.

[0115] [Preparation of dielectric paste] 100 parts by weight of barium titanate (trade name HPBT-1 manufactured by Fuji Titanium Industry Co., Ltd.), 10 parts by weight of polyvinyl butyral (trade name BL-1 manufactured by Sekisui Chemical Co., Ltd.), 5 parts by weight of dibutyl phthalate, and 60 parts by weight of toluene-ethanol (mass ratio 30:30) were mixed and dispersed using a jet mill for 20 hours, and then filtered to prepare a paste-like dielectric paste.

[0116] [Preparation of Adhesive Q] After adding 97 parts by mass of butyl acrylate, 3 parts by mass of acrylic acid, 0.2 parts by mass of azobisisobutyronitrile (azobisisobutyronitrile) as a polymerization initiator, and 233 parts by mass of ethyl acetate, nitrogen gas was introduced and nitrogen replacement was carried out for about 1 hour while stirring. Then, the flask was heated to 60°C and reacted for 7 hours to obtain an acrylic polymer with a weight average molecular weight (Mw) of 1.1 million. In the acrylic polymer solution (with the solid component set at 100 parts by mass), 0.8 parts by mass of trimethylolpropane toluene diisocyanate (trade name "Coronate (registered trademark) L", manufactured by Nippon Polyurethanes Industries, Ltd.) as an isocyanate crosslinking agent and 0.1 parts by mass of silane coupling agent (trade name "KBM-403", manufactured by Shin-Etsu Chemical Co., Ltd.) were added to prepare the adhesive composition (adhesive Q).

[0117] [Preparation of Coating R] Referring to Japanese Patent Application Publication No. 9-227627, a PVA with a saponification degree of 88, an average degree of polymerization of 300, and a copolymerization amount of 1,2-ethylene glycol of 10 mol% was prepared. The PVA was dissolved in water to obtain coating R at a mass percentage of 4%.

[0118] [Preparation of Coating S] Referring to Japanese Patent Application Publication No. 9-227627, a PVA with a saponification degree of 88, an average degree of polymerization of 200, and a copolymerization amount of sodium sulfonate of 3 mol% was prepared. The PVA was dissolved in water to obtain coating S at a mass percentage of 4%.

[0119] [Preparation of Coating T] Referring to Japanese Patent Application Publication No. 2004-230772, ethylene propylene copolymer and ethylene hexene copolymer were synthesized separately. Coating T was obtained by adjusting 53 parts by mass of ethylene propylene copolymer, 42 parts by mass of ethylene hexene copolymer, and 1 part by mass of nonionic surfactant (polyoxyethylene sorbitol monolaurate) "Leodol (registered trademark) TW-L120" manufactured by Kao Corporation, with toluene-ethyl acetate (mass ratio 85:15) as solvent and the solid content being 1.5% by mass.

[0120] (Example 1) 80 parts by weight of PET-1 and 20 parts by weight of MB-A, which are used as raw materials to form layers A and B, were mixed and vacuum dried at 160°C for 2 hours. The mixture was then fed into an extruder and melted at 280°C. The mixture was extruded through a die onto a casting drum with a surface temperature of 25°C to produce an unstretched sheet. The sheet was then preheated using heated rollers and stretched 3.8 times along the long side direction (MD direction) at 90°C. It was then cooled using rollers at 25°C to obtain a uniaxially stretched film. Coating agent D was applied to the obtained uniaxially stretched film using a bar coating method to achieve a dry coating thickness of 100 nm. Then, while holding both ends of the film with clamps, the film was stretched 4.3 times along the width direction (TD direction) perpendicular to the long side direction in a heated area at 100°C in a tenter frame. Subsequently, heat curing was performed in the heat treatment area of ​​the tenter frame at 230°C for 10 seconds. Subsequently, after being uniformly and slowly cooled in the cooling zone, the film is wound up to obtain a laminated polyester film with multiple layers X.

[0121] On the side opposite to the surface in contact with the polyester film of the obtained laminated polyester film, coating agent A is applied in such a way that the thickness of the dried layer Y is 100 nm, thereby obtaining a laminated polyester film.

[0122] A dielectric paste was applied as a release agent to the obtained laminated polyester film using a die-coating method to achieve a dried thickness of 1.0 μm. After 15 seconds of application, the film was dried in an oven at 100°C for 2 minutes at a wind speed of 5 m / s. A roll of laminated polyester film, from which the dielectric (release agent) was removed and peeled off from the obtained laminate, was then obtained. This roll was fed into a washing apparatus equipped with a roll-out device and a roll-up device, and washed with water at 100°C for 2 minutes under a tension of 30 N / m to recover the polyester film from which layers X and Y were removed.

[0123] The evaluation results are shown in the table.

[0124] (Examples 2 to 7) Except for the use of coating E in Example 2, coating F in Example 3, coating G in Example 4, coating H in Example 5, coating I in Example 6, and coating J in Example 7, the laminated polyester film was prepared in the same manner as in Example 1. After the laminate was removed from the mold release material, layers X and Y were removed and the polyester film was reused.

[0125] (Examples 8, Examples 9) Except for changing the thickness of layer X as described in the table, the laminated polyester film was made in the same manner as in Example 3. After the laminate was removed by the release agent, layers X and Y were removed and the polyester film was reused.

[0126] (Example 10) Except that the polyester raw material used was changed to PEN, a laminated polyester film was made in the same way as in Example 3. After the laminate was removed by the release agent, layers X and Y were removed and the polyester film was reused.

[0127] (Examples 11 and 12) Except for changing the thickness of layer Y as described in the table, the laminated polyester film was prepared in the same manner as in Example 3. After the laminate was removed from the mold, layers X and Y were removed, and the polyester film was reused. Furthermore, in the evaluation of the removability of layers X and Y after Q. hydrothermal treatment, the thickness of layer Y was changed as described in the table, and the evaluation was performed.

[0128] (Example 13) Except that coating agent B was used as layer Y, a laminated polyester film was prepared in the same manner as in Example 3. After the laminate was removed by a release agent, layers X and Y were removed, and the polyester film was reused. Furthermore, in the evaluation of the removability of layers X and Y after Q. hydrothermal treatment, coating agent B was used instead of coating agent A for layer Y, and the evaluation was conducted.

[0129] (Example 14) Except that coating C was used as layer Y, and after drying, UV irradiation was performed in an environment with an oxygen concentration of 0.1% by volume and a cumulative light intensity of 200 mJ / cm2, a laminated polyester film was prepared in the same manner as in Example 3. After lamination with a release agent, the film was peeled off, and then layers X and Y were removed, and the polyester film was reused. Furthermore, in the evaluation of the removability of layers X and Y after Q. hydrothermal treatment, coating C was used instead of coating A as layer Y, and after drying, UV irradiation was performed in an environment with an oxygen concentration of 0.1% by volume and a cumulative light intensity of 200 mJ / cm2, and layer Y was laminated and evaluated.

[0130] (Examples 15 to 17) Except for coating K used as layer X in Example 15, coating L used in Example 16, and coating M used in Example 17, the laminated polyester film was made in the same manner as in Example 1. After the laminate was removed from the mold, layers X and Y were removed and the polyester film was reused.

[0131] (Example 19) 30 parts by weight of PET-1 and 20 parts by weight of MB-B, which are used as raw materials to form side A and side B, were mixed and vacuum dried at 160°C for 2 hours. The mixture was then fed into an extruder and melted at 280°C. The mixture was extruded through a die onto a casting drum with a surface temperature of 25°C to produce an unstretched sheet. The sheet was then preheated using heated rollers and stretched 3.8 times along the long side direction (MD direction) at 90°C. It was then cooled using rollers at 25°C to obtain a uniaxially stretched film. Coating agent F was applied to the side A of the obtained uniaxially stretched film using a bar coating method, with the dried and stretched coating thickness reaching 100 nm. Then, while holding both ends of the film with clamps, the film was stretched 4.3 times along the width direction (TD direction) perpendicular to the long side direction in a heated area at 100°C in a tenter frame. Next, heat-fixing was performed for 10 seconds at 230°C in the heat treatment zone of the tenter frame. After uniform and slow cooling in the cooling zone, it was wound into a roll shape to obtain a laminated polyester film with layer X. Using a portion of the obtained laminated polyester film with layer X, coating agent A was applied to the upper surface of layer X (the side opposite to the side of layer X that contacts the polyester film) using a gravure coating method, with a thickness of layer Y of 0.1 μm, to obtain a laminated polyester film with layers X and Y. Then, using the laminated polyester film with layers X and Y thus prepared as a release film, a dielectric paste was applied to the side of layer Y opposite to the side that contacts layer X, with a dried thickness of 1.0 μm as the release material, using a die-coating method. Finally, a release film roll was obtained for the step of demolding the dielectric from the obtained laminate and peeling off the release material. The film roll is fed into a washing device equipped with a roll-out device and a take-up device, and washed with water at 60°C for 2 minutes under a tension of 100 N / m to remove layers X and Y.

[0132] (Example 20) Except that the thickness of layer X is set as described in the table, a laminated polyester film with layer X, a polyester film with layers X and Y, and a release film are obtained in the same manner as in Example 19. The characteristics of each are shown in the table.

[0133] The release film using a laminated film having layer X without being stored in a humid and hot environment, and the release film using a laminated film having layer X after being stored in a humid and hot environment, have layers X and Y that are practically problem-free to remove, and are also problem-free to use as a release film.

[0134] (Example 21) Raw materials obtained by mixing 95 parts by mass of PET-1 and 5 parts by mass of MB-D as raw materials constituting side A and vacuum drying at 160°C for 2 hours, and raw materials obtained by mixing 50 parts by mass of PET-1 and 50 parts by mass of MB-B as raw materials constituting side B and vacuum drying at 160°C for 2 hours, were respectively fed into their respective extruders and melted at 280°C. After being laminated by a confluence device with the thickness of the layer constituting side A (layer A) and the thickness of the layer constituting side B (layer B) being 5 / 95, the layers were extruded through a die onto a casting drum with a surface temperature of 25°C to produce an unstretched sheet. Then, the sheet was preheated using heated rollers and stretched 3.8 times along the long side direction (MD direction) at 90°C. After being cooled using rollers at 25°C, a uniaxial stretched film was obtained. Coating agent F was applied to side A of the obtained uniaxially stretched film using a bar coating method, with the coating thickness dried and stretched to 100 nm. Then, while holding both ends of the film with clamps, it was stretched 4.3 times in the width direction (TD direction) perpendicular to the long side in a heating zone at 100°C within a tenter frame. Next, it was heat-fixed at 230°C for 10 seconds in a heat treatment zone within the tenter frame. After uniform and slow cooling in a cooling zone, it was wound into a roll shape to obtain a laminated polyester film with multiple layers X.

[0135] Next, using a portion of the obtained laminated polyester film, coating agent A is applied to the side opposite to the surface of the laminated polyester film with layer X and the surface in contact with the polyester film, such that the thickness of layer Y is 0.1 μm, and the coating is performed by gravure coating, thereby obtaining a laminated polyester film with layers X and Y.

[0136] The release film using a laminated film having layer X without being stored in a humid and hot environment, and the release film using a laminated film having layer X after being stored in a humid and hot environment, have excellent removability of layers X and Y, and are also excellent as release films.

[0137] (Example 22) Except for changing the thickness of layer X as described in the table, a laminated polyester film with layer X, a polyester film with layers X and Y, and a release film were obtained in the same manner as in Example 21. The characteristics of each are shown in the table.

[0138] The release film using a laminated film having layer X without being stored in a humid and hot environment, and the release film using a laminated film having layer X after being stored in a humid and hot environment, have layers X and Y that are practically problem-free to remove, and are also problem-free to use as a release film.

[0139] (Example 23) Except for the raw material obtained by mixing 95 parts by mass of PET-1 and 5 parts by mass of MB-D as raw materials constituting side A, and the raw material obtained by mixing 10 parts by mass of PET-1 and 90 parts by mass of MB-C as raw materials constituting side B, a laminated polyester film with layer X, a polyester film with layers X and Y, and a release film were obtained in the same manner as in Example 22. The characteristics of each are shown in the table.

[0140] The release film using a laminated film having layer X without being stored in a humid and hot environment, and the release film using a laminated film having layer X after being stored in a humid and hot environment, have excellent removability of layers X and Y, and are also excellent as release films.

[0141] (Example 24) In Example 21, adhesive Q was used as the release agent, and it was coated by a die-coating method to a thickness of 10 μm after drying. Then, a release film roll was obtained for the step of releasing adhesive Q and peeling off the release agent from the obtained laminate. The film roll was fed into a water washing device with a roll-out device and a take-up device, and washed with water at 60°C for 2 minutes under a tension of 100 N / m to remove layers X and Y.

[0142] The release film using a laminated film having layer X without being stored in a humid and hot environment, and the release film using a laminated film having layer X after being stored in a humid and hot environment, have excellent removability of layers X and Y, and are also excellent as release films.

[0143] (Example 25) The raw materials obtained by mixing 95 parts by mass of PET-1 and 5 parts by mass of MB-D as raw materials constituting surface A and vacuum drying at 160°C for 2 hours, the raw materials obtained by mixing 50 parts by mass of PET-1 and 50 parts by mass of MB-B as raw materials constituting surface B and vacuum drying at 160°C for 2 hours, and the raw materials obtained by vacuum drying PET-1, which constitutes the layer (A layer) constituting surface A and the layer (B layer) constituting surface B, at 160°C for 2 hours, were respectively fed into their respective extruders, melted at 280°C, and laminated in the order of layer A / layer C / layer through a confluence device, with the thickness of each layer being 5 / 90 / 5. After lamination, the layers were extruded through a die onto a casting drum with a surface temperature of 25°C to produce an unstretched sheet. Next, the sheet is preheated using heated rollers, stretched 3.8 times along the long side (MD direction) at 90°C, and then cooled using rollers at 25°C to obtain a uniaxially stretched film. Coating agent F is applied to the obtained uniaxially stretched film using a bar coating method, with the dried and stretched coating thickness reaching 100 nm. Then, while holding both ends of the film with clamps, it is stretched 4.3 times along the width direction (TD direction) perpendicular to the long side in the heating zone at 100°C within a tenter frame. Immediately afterwards, it is heat-set at 230°C for 10 seconds in the heat treatment zone within the tenter frame. After uniform and slow cooling in the cooling zone, it is wound into a roll shape to obtain a laminated polyester film with multiple layers (X).

[0144] Next, using a portion of the obtained laminated polyester film, coating agent A is applied to the side opposite to the surface of the laminated polyester film with layer X and the surface in contact with the polyester film, such that the thickness of layer Y is 0.1 μm, and the coating is performed by gravure coating, thereby obtaining a laminated polyester film with layers X and Y.

[0145] (Example 26) Except for using coating M as layer X, a laminated polyester film with layer X, a polyester film with layers X and Y, and a release film were obtained in the same manner as in Example 21.

[0146] (Reference Example 1) The polyester film obtained in Example 21, from which layers X and Y have been removed, was cut and fed into an extruder with venting holes. The pressure was maintained at 1 kPa or less, and while removing moisture, it was extruded at 280°C and processed into granules to obtain recycled raw material-1. The recycled raw material has a glass transition temperature of 81°C, a melting point of 255°C, an intrinsic viscosity of 0.58, and a terminal carboxyl group content of 28 eq. / t. The recycled raw material contains 0.47% by mass of components other than polyester.

[0147] (Reference Example 2) The polyester film obtained in Example 25, from which layers X and Y have been removed, was cut and fed into an extruder with venting holes. The pressure was maintained at below 1 kPa, and while removing moisture, it was extruded at 280°C and processed into granules to obtain recycled raw material-2. The recycled raw material has a glass transition temperature of 81°C, a melting point of 255°C, an intrinsic viscosity of 0.58, and a terminal carboxyl group content of 28 eq. / t. The recycled raw material contains 0.03% by mass of components other than polyester.

[0148] (Example 27) Using a raw material obtained by mixing 95 parts by mass of PET-1 and 5 parts by mass of MB-D as raw materials constituting surface A and vacuum drying at 160°C for 2 hours, a raw material obtained by mixing 50 parts by mass of PET-1 and 50 parts by mass of MB-B as raw materials constituting surface B and vacuum drying at 160°C for 2 hours, and a raw material obtained by mixing 50 parts by mass of PET-1 that constitutes the layer (A layer) constituting surface A and the intermediate layer (C layer) constituting the layer (B layer) constituting surface B, and a raw material obtained by vacuum drying at 160°C for 2 hours with 50 parts by mass of recycled raw material obtained in Reference Example 1, a laminated polyester film with layer X, a polyester film with layers X and Y, and a release film were obtained in the same manner as in Example 25.

[0149] (Examples 28 to 30) Except for the use of coating K as layer X in Example 28, coating G in Example 29, and coating L in Example 30, the laminated polyester film was prepared in the same manner as in Example 21.

[0150] (Example 31) Using a raw material obtained by mixing 85 parts by mass of PET-1, 5 parts by mass of MB-D, and 10 parts by mass of recycled raw material-1 obtained in Reference Example 1 and vacuum drying at 160°C for 2 hours, a raw material obtained by mixing 50 parts by mass of PET-1 and 50 parts by mass of MB-B, which are raw materials constituting side B, and vacuum drying at 160°C for 2 hours, and a raw material obtained by vacuum drying at 160°C for 2 hours of the intermediate layer (C layer) constituting side A (layer A) and the layer (layer B) constituting side B (layer B), a laminated polyester film having layer X, a polyester film having layers X and Y, and a release film were obtained in the same manner as in Example 25.

[0151] (Example 32) Using a raw material obtained by mixing 85 parts by mass of PET-1, 5 parts by mass of MB-D, and 10 parts by mass of recycled raw material-1 obtained in Reference Example 1 and vacuum drying at 160°C for 2 hours, a raw material obtained by mixing 10 parts by mass of PET-1, 40 parts by mass of MB-B, and 10 parts by mass of recycled raw material-1 obtained in Reference Example 1 and vacuum drying at 160°C for 2 hours, and a raw material obtained by vacuum drying at 160°C for 2 hours of the intermediate layer (C layer) of the layer (A layer) constituting the layer (B layer) constituting the layer (B layer) of the layer constituting the layer of ...

[0152] (Example 33) Using a raw material obtained by mixing 85 parts by mass of PET-1, 5 parts by mass of MB-D, and 10 parts by mass of recycled raw material-1 obtained in Reference Example 1 and vacuum drying at 160°C for 2 hours, a raw material obtained by mixing 10 parts by mass of PET-1, 40 parts by mass of MB-B, and 10 parts by mass of recycled raw material-1 obtained in Reference Example 1 and vacuum drying at 160°C for 2 hours, and a raw material obtained by vacuum drying at 160°C for 2 hours, i.e., 50 parts by mass of PET-1 and 50 parts by mass of recycled raw material-1 obtained in Reference Example 1, which constitutes the intermediate layer (layer A) of layer A and the layer (layer B) of layer B, a laminated polyester film having layer X, a polyester film having layers X and Y, and a release film, in the same manner as in Example 25, a laminated polyester film having layers X and Y was obtained.

[0153] (Example 34) Using a raw material obtained by mixing 85 parts by mass of PET-1, 5 parts by mass of MB-D, and 10 parts by mass of recycled raw material-1 obtained in Reference Example 1 and vacuum drying at 160°C for 2 hours, a raw material obtained by mixing 50 parts by mass of PET-1 and 50 parts by mass of MB-B, which are raw materials constituting the B side, and vacuum drying at 160°C for 2 hours, and a raw material obtained by vacuum drying at 160°C for 2 hours of the intermediate layer (C layer) constituting the layer (A layer) of the A side and the layer (B layer) of the B side, i.e., 100 parts by mass of PET-1, which is the raw material of the intermediate layer (C layer) constituting the A side (A layer) and the layer (B layer) constituting the B side (B layer), a laminated polyester film with layer X, a polyester film with layers X and Y, and a release film were obtained in the same manner as in Example 25.

[0154] (Examples 35 and 36) Except for the aspect in Example 35 where 95 parts by weight of PET-1 and 5 parts by weight of MB-D were used as raw materials to form surface A and surface B, and in Example 36 where 30 parts by weight of PET-1 and 70 parts by weight of MB-C were used as raw materials to form surface A and surface B, a laminated polyester film with layer X, a polyester film with layers X and Y, and a release film were obtained in the same manner as in Example 19.

[0155] (Example 37) Except for the raw material obtained by mixing 50 parts by mass of PET-1 and 50 parts by mass of MB-B as raw materials constituting side A and vacuum drying at 160°C for 2 hours, and the raw material obtained by mixing 95 parts by mass of PET-1 and 5 parts by mass of MB-D as raw materials constituting side B and vacuum drying at 160°C for 2 hours, a laminated polyester film with layer X, a polyester film with layers X and Y, and a release film were obtained in the same manner as in Example 21.

[0156] (Example 38) A single side (A side) of the polyester film "Lumirror" (registered trademark) #50T60 manufactured by Toray Industries, Inc. was coated with coating agent F by gravure coating method with a coating thickness of 100 nm after drying, and then rolled into a roll shape to obtain a laminated polyester film with multiple layers X.

[0157] Next, using a portion of the obtained laminated polyester film, coating agent A is applied to the side of the laminated polyester film with layer X opposite to the side in contact with the polyester film, such that the thickness of layer Y is 0.1 μm, and a gravure coating method is used to obtain a laminated polyester film with layers X and Y. Furthermore, the intrinsic viscosity after reuse was not measured.

[0158] (Example 39) Except that coating agent R is used as a component of layer X, a laminated polyester film with layer X, a polyester film with layers X and Y, and a release film are obtained in the same manner as in Example 21.

[0159] (Example 40) 80 parts by weight of PET-1 and 20 parts by weight of MB-A, which are used as raw materials to form layers A and B, were mixed, vacuum dried at 160°C for 2 hours, and then fed into an extruder. The mixture was melted at 280°C and extruded through a die onto a casting drum with a surface temperature of 25°C to produce an unstretched sheet. The sheet was then preheated using heated rollers and stretched 3.5 times along the long side direction (MD direction) at 95°C. It was then cooled using rollers at 25°C to obtain a uniaxially stretched film. Coating agent S was applied to the obtained uniaxially stretched film using a bar coating method to achieve a dried coating thickness of 100 nm. Then, while holding both ends of the film with clamps, it was stretched 3.7 times along the width direction (TD direction) perpendicular to the long side direction in a heated area at 95°C within a tenter frame. Subsequently, heat curing was performed for 10 seconds at 220°C in a heat treatment area within the tenter frame. Subsequently, after being uniformly and slowly cooled in the cooling zone, the film is wound up to obtain a laminated polyester film with multiple layers X.

[0160] On the side opposite to the surface in contact with the polyester film of the obtained laminated polyester film, coating agent A is applied in such a way that the thickness of the dried layer Y is 100 nm, thereby obtaining a laminated polyester film.

[0161] A dielectric paste was applied as a release agent to the obtained laminated polyester film using a die-coating method to achieve a dried thickness of 1.0 μm. After 15 seconds of application, the film was dried in an oven at 100°C for 2 minutes at a wind speed of 5 m / s. A film roll was then obtained, consisting of a laminated polyester film from which the dielectric (release agent) was demolded and peeled off. This film roll was fed into a washing apparatus equipped with a roll-out device and a winding device, and washed with water at 100°C for 2 minutes under a tension of 30 N / m to recover the polyester film from which layers X and Y were removed.

[0162] (Example 41) Except that the transverse stretching temperature is set as described in the table, a laminated polyester film with layer X, a polyester film with layers X and Y, and a release film are obtained in the same manner as in Example 21.

[0163] (Example 42) Raw materials obtained by mixing 95 parts by mass of PET-1 and 5 parts by mass of MB-D as raw materials constituting side A and vacuum drying at 160°C for 2 hours, and raw materials obtained by mixing 50 parts by mass of PET-1 and 50 parts by mass of MB-B as raw materials constituting side B and vacuum drying at 160°C for 2 hours, were respectively fed into their respective extruders and melted at 280°C. After being laminated by a confluence device with the thickness of the layer constituting side A (layer A) and the thickness of the layer constituting side B (layer B) being 5 / 95, the layers were extruded through a die onto a casting drum with a surface temperature of 25°C to produce an unstretched sheet. Next, the sheet was preheated using heated rollers and stretched 3.8 times along the long side direction (MD direction) at 90°C. Then, it was cooled using rollers at 25°C to obtain a uniaxial stretched film. While holding both ends of the obtained uniaxially stretched film with clamps, it is stretched 4.3 times in the width direction (TD direction) perpendicular to the long side direction in the heating zone at 100°C inside the tenter frame. Then, it is heat-fixed for 10 seconds at 230°C in the heat treatment zone inside the tenter frame. After being uniformly and slowly cooled in the cooling zone, it is wound into a roll shape to obtain a laminated polyester film without laminated layer X.

[0164] On one side of the unlaminated polyester film, a coating agent D is applied to form a layer Y with a thickness of 0.1 μm after drying, thereby obtaining a laminated polyester film with a laminated layer Y.

[0165] On the side of layer Y opposite to the side in contact with the polyester film, a dielectric paste is applied as a release agent with a dried thickness of 1.0 μm using a die-coating method. Then, a release film roll is obtained for the step of demolding the dielectric and peeling off the release agent from the obtained laminate. The film roll is fed into a water washing device equipped with a roll-out device and a take-up device, and washed with water at 60°C for 2 minutes under a tension of 100 N / m to remove layer Y. Furthermore, in the evaluation of the removability of layers X and Y after Q. hydrothermal treatment, coating agent D is used instead of coating agent A for layer Y and the evaluation is performed.

[0166] (Comparative Example 1, Comparative Example 2) Except that PET-1 was used as the raw material for forming side A and side B, and coating agent N was used as layer X in Comparative Example 1 and coating agent O was used in Comparative Example 2, the laminated polyester film was made in the same way as in Example 1. After the laminate was removed from the mold, layers X and Y were removed and the polyester film was reused.

[0167] In Comparative Example 1, where the saponification degree of the PVA constituting layer X is high, the polar component γXP and the hydrogen bonding component γXH of the surface free energy of layer X are not within the optimal range, resulting in poor removability of layers X and Y. Then, according to item N, the pulverized polyester film was melt-extruded, and as a result, layers X and Y could not be removed and remained, thus deteriorating in the extruder and failing to form sheets.

[0168] In Comparative Example 2, where the average degree of polymerization of the PVA constituting layer X is high, the polar component γXP and the hydrogen bonding component γXH of the surface free energy of layer X are not in the optimal range, resulting in poor removability of layers X and Y. Then, according to item N, the pulverized polyester film was melt-extruded, and as a result, layers X and Y could not be removed and remained, thus deteriorating in the extruder and failing to form sheets.

[0169] (Comparative Example 3) Except for using coating A as layer Y, a laminated polyester film was prepared in the same manner as in Example 42. Ceramic green sheets and adhesive sheets were laminated as demolding materials and evaluated. After peeling off the ceramic green sheets, layer Y was removed and the polyester film was reused.

[0170] Since layer X is not present and the HY(1)-HY(20) (°) of layer Y is not in a favorable range, the removability of layer Y is poor. Then, according to item N, the pulverized polyester film is melt-extruded, and as a result, layer Y cannot be removed and remains, thus deteriorating in the extruder and failing to form a sheet.

[0171] [Table 1] [Table 1] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Example 10 polyester film A floor Raw materials PET-1 MB-A PET-1 MB-A PET-1 MB-A PET-1 MB-A PET-1 MB-A PET-1 MB-A PET-1 MB-A PET-1 MB-A PET-1 MB-A PEN MB-A B layer constitutive raw materials PET-1 MB-A PET-1 MB-A PET-1 MB-A PET-1 MB-A PET-1 MB-A PET-1 MB-A PET-1 MB-A PET-1 MB-A PET-1 MB-A PEN MB-A RzjisB (nm) 235 235 235 235 235 235 235 235 235 214 IV 0.64 0.64 0.64 0.64 0.64 0.64 0.64 0.64 0.64 0.61 Manufacturing conditions double Temperature (℃) 90 90 90 90 90 90 90 90 90 120 magnification 3.8 3.8 3.8 3.8 3.8 3.8 3.8 3.8 3.8 3.8 Horizontal double Temperature (°C) 100 100 100 100 100 100 100 100 100 150 magnification 4.3 4.3 4.3 4.3 4.3 4.3 4.3 4.3 4.3 3.8 Heat treatment temperature (°C) 230 230 230 230 230 230 230 230 230 230 Thickness (nm) 30 30 30 30 30 30 30 30 30 30

[0172] [Table 2] [Table 2] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Example 10 Layer X Does it have a PVA skeleton? ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ Does it have a sulfonate-modified PVA backbone? ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ Modified base Sodium sulfonate Sodium sulfonate Sodium sulfonate Sodium sulfonate Sodium sulfonate Sodium sulfonate Sodium sulfonate Sodium sulfonate Sodium sulfonate Sodium sulfonate Copolymer content (mol%) 0.1 0.5 1 3 5 1 1 1 1 1 degree of saponification 88 88 88 88 88 88 88 88 88 88 Average degree of polymerization 500 500 500 400 300 1000 300 500 500 500 Thickness (xa) (nm) 100 100 100 100 100 100 100 1000 50 100 RzjisX (nm) 98 98 98 98 98 98 98 98 98 95 RzjisX / xa 1.0 1.0 1.0 1.0 1.0 1.0 1.0 0.1 2.0 1.0 Surface free energy (mN / m) Total 51.2 51.6 55.5 58.8 59.2 54.0 57.2 55.5 55.5 55.5 Dispersed components twenty four twenty three twenty four twenty three twenty two twenty four twenty three twenty four twenty four twenty four polar component γX P twenty one twenty two twenty four 28 29 20 28 twenty four twenty four twenty four Hydrogen bond component γX H 6.2 6.6 7.5 7.8 8.2 10 6.2 7.5 7.5 7.5 Water contact angle HX (1) (°) 41 41 39 32 twenty four 54 33 39 39 39 Water contact angle HX (20) (°) 25 20 19 14 9 48 7 twenty two 16 20 |HX(1)-HX(20)| 16 twenty one 20 18 15 6 26 17 twenty three 19 Crystallinity 35 34 33 20 14 38 32 33 33 33 RzjisB / xa 2.4 2.4 2.4 2.4 2.4 2.4 2.4 0.2 4.7 2.1

[0173] [Table 3] [Table 3] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Example 10 Layer Y Main components Addition reaction silicone Addition reaction silicone Addition reaction silicone Addition reaction silicone Addition reaction silicone Addition reaction silicone Addition reaction silicone Addition reaction silicone Addition reaction silicone Addition reaction silicone Thickness (nm) 100 100 100 100 100 100 100 100 100 100 Surface free energy (mN / m) Dispersed components 11 10 10 10 10 10 10 11 10 10 polar component γY P 0.2 0.3 0.4 1.2 1.8 0.3 0.4 0.6 0.3 0.4 Hydrogen bond component γY H 1.5 1.6 1.8 1.7 1.7 2.4 1.8 2.0 1.7 1.8 Water contact angle HY (1) (°) 109 109 109 109 109 109 109 109 109 109 Water contact angle HY (20) (°) 95 95 95 97 99 99 90 95 95 95 |HY(1)-HY(20)|(°) 14 14 14 12 10 10 19 14 14 14 F(A) (mN / 50 mm) 90 90 90 90 90 90 90 90 90 90 F(B) (mN / 50 mm) 820 690 560 560 500 450 900 600 640 560 Solvent durability (%) 11 13 16 16 18 20 10 15 14 16 Release film Demolding material barium titanium oxide barium titanium oxide barium titanium oxide barium titanium oxide barium titanium oxide barium titanium oxide barium titanium oxide barium titanium oxide barium titanium oxide barium titanium oxide The peelability of the demolded material peeling force (mN / 50 mm) 45 40 40 40 40 40 45 40 40 40 Solvent resistance as an indicator of haze change Hz (A) (%) 6 6 6 6 6 6 6 6 6 4 Hz (B) (%) 7 6 6 6 6 6 7 6 6 4 ΔHz (%) 1 0 0 0 0 0 1 0 0 0 Solvent resistance as an indicator of surface roughness change Surface roughness Sa (A) (nm) 5 5 5 5 5 5 5 4 6 4 Surface roughness Sa (B) (nm) 6 5 5 5 5 5 6 4 6 4 ΔSa (nm) 1 0 0 0 0 0 1 0 0 0 Removability of layer X and layer Y Removal methods Water wash Water wash Water wash Water wash Water wash Water wash Water wash Water wash Water wash Water wash Contact angle (°) of the removed water 80 82 70 75 82 85 80 85 66 70 Reusability Reuse methods Melt extrusion Melt extrusion Melt extrusion Melt extrusion Melt extrusion Melt extrusion Melt extrusion Melt extrusion Melt extrusion Melt extrusion IV(R) 0.52 0.50 0.60 0.60 0.50 0.48 0.52 0.50 0.60 0.60 Removability of layers X and Y after hydrothermal treatment Removal methods Water wash Water wash Water wash Water wash Water wash Water wash Water wash Water wash Water wash Water wash Contact angle (°) of the removed water 91 93 81 86 93 93 91 93 77 81

[0174] [Table 4] [Table 4] Example 11 Example 12 Example 13 Example 14 Example 15 Example 16 Example 17 Comparative Example 1 Comparative Example 2 polyester film A layer Raw materials PET-1 MB-A PET-1 MB-A PET-1 MB-A PET-1 MB-A PET-1 MB-A PET-1 MB-A PET-1 MB-A PET-1 PET-1 B Floor Raw materials PET-1 MB-A PET-1 MB-A PET-1 MB-A PET-1 MB-A PET-1 MB-A PET-1 MB-A PET-1 MB-A PET-1 PET-1 RzjisB (nm) 235 235 235 235 235 235 235 10 10 IV 0.64 0.64 0.64 0.64 0.64 0.64 0.64 0.65 0.65 Manufacturing conditions Double Temperature (°C) 90 90 90 90 90 90 90 90 90 magnification 3.8 3.8 3.8 3.8 3.8 3.8 3.8 3.8 3.8 Yokomoto Temperature (°C) 100 100 100 100 100 100 100 100 100 magnification 4.3 4.3 4.3 4.3 4.3 4.3 4.3 4.3 4.3 Heat treatment temperature (°C) 230 230 230 230 230 230 230 235 235 Thickness (nm) 30 30 30 30 30 30 30 30 30

[0175] [Table 5] [Table 5] Example 11 Example 12 Example 13 Example 14 Example 15 Example 16 Example 17 Comparative Example 1 Comparative Example 2 Layer X Does it have a PVA skeleton? ○ ○ ○ ○ ○ ○ ○ ○ ○ Does it have a sulfonate-modified PVA backbone? ○ ○ ○ ○ × × × ○ ○ Modified base Sodium sulfonate Sodium sulfonate Sodium sulfonate Sodium sulfonate - Sodium carboxylate 1,2-Ethylene glycol Sodium sulfonate Sodium sulfonate Copolymer content (mol%) 1 1 1 1 - 1 6 1 1 degree of saponification 88 88 88 88 88 88 88 98 88 Average degree of polymerization 500 500 500 500 500 1000 450 500 2500 Thickness (xa) (nm) 100 100 100 100 100 100 100 100 100 RzjisX (nm) 98 98 98 98 98 98 98 10 10 RzjisX / xa 1.0 1.0 1.0 1.0 1.0 1.0 1.0 0.1 0.1 Surface free energy (mN / m) sum 55.5 55.5 55.5 55.5 56.8 58.8 60.3 57.0 43.0 Dispersed components twenty four twenty four twenty four twenty four 25 twenty three 25 twenty three twenty four polar component γX P twenty four twenty four twenty four twenty four 26 32 31 19 5 Hydrogen bond component γX H 7.5 7.5 7.5 7.5 5.8 3.8 4.3 15 14 Water contact angle HX (1) (°) 39 39 39 39 47 40 49 twenty three 62 Water contact angle HX (20) (°) 19 19 19 19 33 14 17 12 59 |HX(1)-HX(20)| 20 20 20 20 14 26 32 11 3 Crystallinity 33 33 33 33 35 38 3 38 42 RzjisB / xa 2.4 2.4 2.4 2.4 2.4 2.4 2.4 0.1 0.1

[0176] [Table 6] [Table 6] Example 11 Example 12 Example 13 Example 14 Example 15 Example 16 Example 17 Comparative Example 1 Comparative Example 2 Layer Y Main components Addition reaction silicone Addition reaction silicone Condensation reaction type silicone UV-cured silicone Addition reaction silicone Addition reaction silicone Addition reaction silicone Addition reaction silicone Addition reaction silicone Thickness (nm) 10 1000 100 100 100 100 100 100 100 Surface free energy (mN / m) Dispersed components 11 9 10 10 11 11 11 10 9 polar component γY P 1.2 0.2 0.5 0.5 0.2 0.6 0.6 0.2 0.1 Hydrogen bond component γY H 3.6 1.5 2.0 1.8 1.3 0.9 1.0 2.5 2.5 Water contact angle HY (1) (°) 109 109 100 104 103 103 103 109 109 Water contact angle HY (20) (°) 90 104 90 91 31 90 26 106 105 |HY(1)-HY(20)|(°) 19 5 10 13 72 13 77 3 4 F(A) (mN / 50 mm) 90 90 150 110 85 90 90 90 90 F(B) (mN / 50 mm) 750 560 830 740 8500 11000 13000 300 410 Solvent durability (%) 12 16 18 15 1.0 0.8 0.7 30 twenty two Release film Demolded material Barium titanate Barium titanate Barium titanate Barium titanate Barium titanate Barium titanate Barium titanate Barium titanate Barium titanate Peelability of the demolded material Peeling force (mN / 50 mm) 40 40 65 45 100 100 95 40 40 Solvent resistance as an indicator of haze change Hz (A) (%) 6 6 6 6 6 6 6 6 6 Hz (B) (%) 6 6 6 6 18 20 twenty one 6 6 ΔHz (%) 0 0 0 0 12 14 15 0 0 Solvent resistance as an indicator of surface roughness Surface roughness Sa (A) (nm) 6 4 5 5 5 5 5 5 5 Surface roughness Sa (B) (nm) 6 4 5 5 13 15 15 5 5 ΔSa (nm) 0 0 0 0 8 10 10 0 0 Removal of layer X and layer Y Removal methods Water wash Water wash Water wash Water wash Water wash Water wash Water wash Water wash Water wash Contact angle (°) of the removed water 65 78 72 70 79 75 76 95 95 Reuse Reuse methods Melt extrusion Melt extrusion Melt extrusion Melt extrusion Melt extrusion Melt extrusion Melt extrusion Melt extrusion Melt extrusion IV(R) 0.60 0.60 0.60 0.60 0.60 0.60 0.60 - - Removability of layers X and Y after hydrothermal treatment Removal methods Water wash Water wash Water wash Water wash Water wash Water wash Water wash Water wash Water wash Contact angle (°) of the removed water 76 90 83 81 90 86 87 98 98

[0177] [Table 7] [Table 7] Example 19 Example 20 Example 21 Example 22 Example 23 Example 24 Example 25 Example 26 Example 27 Example 28 polyester film A layer Raw materials PET-1 MB-B PET-1 MB-B PET-1 MB-D PET-1 MB-D PET-1 MB-D PET-1 MB-D PET-1 MB-D PET-1 MB-D PET-1 MB-D PET-1 MB-D B Floor Raw materials PET-1 MB-B PET-1 MB-B PET-1 MB-B PET-1 MB-B PET-1 MB-C PET-1 MB-B PET-1 MB-B PET-1 MB-B PET-1 MB-B PET-1 MB-B RzjisB (nm) 951 951 813 821 2322 813 823 809 810 813 IV 0.63 0.63 0.63 0.63 0.62 0.63 0.63 0.63 0.63 0.63 Manufacturing conditions Double Temperature (°C) 90 90 90 90 90 90 90 90 90 90 magnification 3.8 3.8 3.8 3.8 3.8 3.8 3.8 3.8 3.8 3.8 Horizontal double Temperature (°C) 100 100 100 100 100 100 100 100 100 100 magnification 4.3 4.3 4.3 4.3 4.3 4.3 4.3 4.3 4.3 4.3 Heat treatment temperature (°C) 235 235 235 235 235 235 235 235 235 235 Thickness (nm) 30 30 30 30 30 30 30 30 30 30

[0178] [Table 8] [Table 8] Example 19 Example 20 Example 21 Example 22 Example 23 Example 24 Example 25 Example 26 Example 27 Example 28 Layer X Does it have a PVA skeleton? ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ Does it have a sulfonate-modified PVA backbone? ○ ○ ○ ○ ○ ○ ○ × ○ × Modified base Sodium sulfonate Sodium sulfonate Sodium sulfonate Sodium sulfonate Sodium sulfonate Sodium sulfonate Sodium sulfonate 1,2-Ethylene glycol Sodium sulfonate - Copolymer content (mol%) 1 1 1 1 1 1 1 6 1 - degree of saponification 88 88 88 88 88 88 88 88 88 88 Average degree of polymerization 500 500 500 500 500 500 500 500 500 500 Thickness (xa) (nm) 100 300 100 500 500 100 100 100 100 100 RzjisX (nm) 903 846 115 90 90 115 104 111 114 115 RzjisX / xa 9.0 2.8 1.2 0.18 0.18 1.2 1.0 1.1 1.1 1.2 Surface free energy (mN / m) Total 54.0 55.5 55.5 58.0 58.0 58.0 55.5 55.5 60.3 56.0 Dispersed components 26 twenty four twenty four twenty three twenty three 26.5 twenty four 20.2 28.8 25.5 polar component γX P twenty two twenty four twenty four 27 27 twenty four twenty four 31 twenty four 25 Hydrogen bond component γX H 6.0 7.5 7.5 8.0 8.0 7.5 7.5 4.3 7.5 5.5 Water contact angle HX (1) (°) 40 41 39 32 32 39 39 51 39 49 Water contact angle HX (20) (°) 19 19 19 14 14 19 19 17 19 34 |HX(1)-HX(20)| twenty one twenty two 20 18 18 20 20 34 20 15 Crystallinity 34 34 34 34 34 34 34 3 34 35 RzjisB / xa 9.5 3.2 8.1 1.6 4.6 8.1 8.2 8.1 8.1 8.1

[0179] [Table 9] [Table 9] Example 19 Example 20 Example 21 Example 22 Example 23 Example 24 Example 25 Example 26 Example 27 Example 28 Layer Y Main components Addition reaction silicone Addition reaction silicone Addition reaction silicone Addition reaction silicone Addition reaction silicone Addition reaction silicone Addition reaction silicone Addition reaction silicone Addition reaction silicone Addition reaction silicone Thickness (nm) 100 100 100 100 100 100 100 100 100 100 Surface free energy (mN / m) Dispersed components 10 10 10 10 10 10 10 11 10 10 polar component γY P 0.3 0.4 0.4 0.5 0.4 0.4 0.4 0.6 0.4 0.4 Hydrogen bond component γY H 1.7 1.8 1.8 1.8 1.8 1.8 1.8 1.0 1.8 1.7 Water contact angle HY (1) (°) 110 110 110 110 110 110 110 110 110 110 Water contact angle HY (20) (°) 107 95 91 85 85 91 89 78 90 107 |HY(1)-HY(20)|(°) 3 15 19 45 45 19 twenty one 32 20 3 F(A) (mN / 50 mm) 90 90 90 90 90 90 90 90 90 90 F(B) (mN / 50 mm) 560 560 560 560 560 560 560 13000 560 1100 Solvent durability (%) 16 16 16 16 16 16 16 0.7 16 9 Release film Demolded material Barium titanate Barium titanate Barium titanate Barium titanate acrylic acid acrylic acid Barium titanate Barium titanate Barium titanate Barium titanate Peelability of the demolded material Peeling force (mN / 50 mm) 30 32 30 31 32 30 30 45 30 41 Solvent resistance as an indicator of haze change Hz (A) (%) 20 20 10 10 15 10 10 10 10 10 Hz (B) (%) 20 20 10 10 15 10 10 twenty four 10 twenty two ΔHz (%) 0 0 0 0 0 0 0 14 0 12 Solvent resistance as an indicator of surface roughness Surface roughness Sa (A) (nm) twenty one 19 6 5 5 6 6 6 6 6 Surface roughness Sa (B) (nm) twenty one 19 6 5 5 6 6 16 6 14 ΔSa (nm) 0 0 0 0 0 0 0 10 0 8 Removal of layer X and layer Y Removal methods Water wash Water wash Water wash Water wash Water wash Water wash Water wash Water wash Water wash Water wash Contact angle (°) of the removed water 90 79 71 71 73 70 70 70 70 94 Reuse Reuse methods Melt extrusion Melt extrusion Melt extrusion Melt extrusion Melt extrusion Melt extrusion Melt extrusion Melt extrusion Melt extrusion Melt extrusion IV(R) 0.51 0.59 0.59 0.59 0.58 0.59 0.59 0.59 0.59 0.50 Removability of layers X and Y after hydrothermal treatment Removal methods Water wash Water wash Water wash Water wash Water wash Water wash Water wash Water wash Water wash Water wash Contact angle (°) of the removed water 94 81 71 86 73 70 70 70 70 94

[0180] [Table 10] [Table 10] Example 29 Example 30 Example 31 Example 32 Example 33 Example 34 Example 35 Example 36 Example 37 polyester film A layer Raw materials PET-1 MB-D PET-1 MB-D PET-1 MB-D Recycled Raw Materials-1 PET-1 MB-D Recycled Raw Materials-1 PET-1 MB-D Recycled Raw Materials-1 PET-1 MB-D Recycled Raw Materials-2 PET-1 MB-D PET-1 MB-C PET-1 MB-B B Floor Raw materials PET-1 MB-B PET-1 MB-B PET-1 MB-B PET-1 MB-B Recycled Raw Materials-1 PET-1 MB-B Recycled Raw Materials-1 PET-1 MB-B PET-1 MB-D PET-1 MB-C PET-1 MB-D RzjisB (nm) 813 813 813 890 890 813 118 1100 121 IV 0.63 0.63 0.63 0.62 0.61 0.63 0.65 0.62 0.65 Manufacturing conditions Double Temperature (°C) 90 90 90 90 90 90 90 90 90 magnification 3.8 3.8 3.8 3.8 3.8 3.8 3.8 3.8 3.8 Yokomoto Temperature (°C) 100 100 100 100 100 100 100 100 100 magnification 4.3 4.3 4.3 4.3 4.3 4.3 4.3 4.3 4.3 Heat treatment temperature (°C) 235 235 235 235 235 235 235 235 235 Thickness (nm) 30 30 30 30 30 30 30 30 30

[0181] [Table 11] [Table 11] Example 29 Example 30 Example 31 Example 32 Example 33 Example 34 Example 35 Example 36 Example 37 Layer X Does it have a PVA skeleton? ○ ○ ○ ○ ○ ○ ○ ○ ○ Does it have a sulfonate-modified PVA backbone? ○ × ○ ○ ○ ○ ○ ○ ○ Modified base Sodium sulfonate Sodium carboxylate Sodium sulfonate Sodium sulfonate Sodium sulfonate Sodium sulfonate Sodium sulfonate Sodium sulfonate Sodium sulfonate Copolymer content (mol%) 3 1 1 1 1 1 1 1 1 degree of saponification 88 88 88 88 88 88 88 88 88 Average degree of polymerization 400 1000 500 500 500 500 500 500 500 Thickness (xa) (nm) 100 100 100 100 100 100 100 100 100 RzjisX (nm) 115 115 311 311 311 280 110 1124 841 RzjisX / xa 1.2 1.2 3.1 3.1 3.1 2.8 1.1 11.1 8.4 Surface free energy (mN / m) sum 58.8 58.8 55.0 55.0 55.0 55.5 55.5 55.5 55.5 Dispersed components twenty three twenty three 25.5 25.5 25.5 twenty four twenty four twenty four twenty four polar component γX P 28 32 twenty three twenty three twenty three twenty four twenty four twenty four twenty four Hydrogen bond component γX H 7.8 3.8 6.5 6.5 6.5 7.5 7.5 7.5 7.5 Water contact angle HX (1) (°) 30 40 40 40 40 39 39 42 41 Water contact angle HX (20) (°) 14 14 19 19 19 19 19 twenty two 19 |HX(1)-HX(20)| 16 26 twenty one twenty one twenty one 20 20 20 twenty two Crystallinity twenty one 38 34 34 34 34 34 34 34 RzjisB / xa 8.1 8.1 8.1 8.9 8.9 8.1 1.2 11.0 1.2

[0182] [Table 12] [Table 12] Example 29 Example 30 Example 31 Example 32 Example 33 Example 34 Example 35 Example 36 Example 37 Layer Y Main components Addition reaction silicone Addition reaction silicone Addition reaction silicone Addition reaction silicone Addition reaction silicone Addition reaction silicone Addition reaction silicone Addition reaction silicone Addition reaction silicone Thickness (nm) 100 100 100 100 100 100 100 100 100 Surface free energy (mN / m) Dispersed components 10 11 10 10 10 10 10 10 10 polar component γY P 0.4 0.6 0.4 0.4 0.4 0.4 0.4 0.4 0.4 Hydrogen bond component γY H 1.8 0.9 1.8 1.8 1.8 1.8 1.8 1.8 1.8 Water contact angle HY (1) (°) 110 110 110 110 110 110 110 110 110 Water contact angle HY (20) (°) 76 100 107 107 107 98 91 109 107 |HY(1)-HY(20)|(°) twenty four 10 3 3 3 12 19 1 3 F(A) (mN / 50 mm) 90 90 90 90 90 90 90 90 90 F(B) (mN / 50 mm) 1000 11000 560 560 560 560 560 560 560 Solvent durability (%) 9 0.8 16 16 16 16 16 16 16 Release film Demolded material Barium titanate Barium titanate Barium titanate Barium titanate Barium titanate Barium titanate Barium titanate Barium titanate Barium titanate Peelability of the demolded material Peeling force (mN / 50 mm) 32 43 30 30 30 30 30 34 32 Solvent resistance as an indicator of haze change Hz (A) (%) 10 10 10 10 10 10 6 12 6 Hz (B) (%) 10 twenty three 10 10 10 10 6 12 6 ΔHz (%) 0 13 0 0 0 0 0 0 0 Solvent resistance as an indicator of surface roughness Surface roughness Sa (A) (nm) 6 6 10 10 10 9 6 twenty two 19 Surface roughness Sa (B) (nm) 6 16 10 10 10 9 6 twenty two 19 ΔSa (nm) 0 10 0 0 0 0 0 0 0 Removal of layer X and layer Y Removal methods Water wash Water wash Water wash Water wash Water wash Water wash Water wash Water wash Water wash Contact angle (°) of the removed water 70 94 90 90 87 83 71 92 91 Reuse Reuse methods Melt extrusion Melt extrusion Melt extrusion Melt extrusion Melt extrusion Melt extrusion Melt extrusion Melt extrusion Melt extrusion IV(R) 0.59 0.50 0.51 0.50 0.57 0.59 0.61 0.50 0.53 Removability of layers X and Y after hydrothermal treatment Removal methods Water wash Water wash Water wash Water wash Water wash Water wash Water wash Water wash Water wash Contact angle (°) of the removed water 70 94 90 90 90 83 97 97 97

[0183] [Table 13] [Table 13] Example 38 Example 39 Example 40 Example 41 Example 42 Comparative Example 3 polyester film A layer Raw materials - PET-1 MB-D PET-1 MB-A PET-1 MB-D PET-1 MB-D PET-1 MB-D B Floor Raw materials - PET-1 MB-B PET-1 MB-A PET-1 MB-B PET-1 MB-B PET-1 MB-B RzjisB (nm) 138 813 235 813 813 813 IV - 0.63 0.64 0.63 0.63 0.63 Manufacturing conditions Vertical double Temperature (°C) 90 90 95 90 90 90 magnification 3.8 3.8 3.5 3.8 3.8 3.8 Horizontal double Temperature (°C) 100 100 95 130 100 100 magnification 4.3 4.3 3.7 4.3 4.3 4.3 Heat treatment temperature (°C) 235 235 220 235 235 235 Thickness (nm) 50 30 30 30 30 30

[0184] [Table 14] [Table 14] Example 38 Example 39 Example 40 Example 41 Example 42 Comparative Example 3 Layer X Does it have a PVA skeleton? ○ ○ ○ ○ × × Does it have a sulfonate-modified PVA backbone? ○ × ○ ○ × × Modified base Sodium sulfonate 1,2-Ethylene glycol Sodium sulfonate Sodium sulfonate - - Copolymer content (mol%) 1 10 3 1 - - degree of saponification 88 88 88 88 - - Average degree of polymerization 500 300 200 500 - - Thickness (xa) (nm) 100 100 100 100 - - RzjisX (nm) 131 111 94 311 - - RzjisX / xa 1.3 1.1 0.9 3.1 - - Surface free energy (mN / m) sum 55.5 61.0 60.5 55.0 Dispersed components twenty four 17 twenty three 25.5 - - polar component γX P twenty four 41 34 twenty three - - Hydrogen bond component γX H 7.5 3.0 3.5 6.5 - - Water contact angle HX (1) (°) 39 51 30 40 - - Water contact angle HX (20) (°) 19 17 5 19 - - |HX(1)-HX(20)| 20 34 25 twenty one - - Crystallinity 34 2 14 38 - - RzjisB / xa 1.4 8.1 2.4 8.1 - -

[0185] [Table 15] [Table 15] Example 38 Example 39 Example 40 Example 41 Example 42 Comparative Example 3 Layer Y Main components Addition reaction silicone Addition reaction silicone Addition reaction silicone Addition reaction silicone Ethylenepropylene / ethylenehexene copolymer Addition reaction silicone Thickness (nm) 100 100 100 100 100 100 Surface free energy (mN / m) Dispersed components 10 11 10 10 28 11 polar component γY P 0.4 0.9 0.3 0.4 0.8 0.2 Hydrogen bond component γY H 1.8 0.8 1.4 1.8 1.0 0.9 Water contact angle HY (1) (°) 110 110 109 110 100 108 Water contact angle HY (20) (°) 92 92 90 107 85 108 |HY(1)-HY(20)|(°) 18 18 19 3 15 0 F(A) (mN / 50 mm) 90 90 90 90 200 90 F(B) (mN / 50 mm) 560 560 1100 560 1000 5000 Solvent durability (%) 16 16 8 16 20 2 Release film Demolded material Barium titanate Barium titanate Barium titanate Barium titanate Barium titanate Barium titanate Peelability of the demolded material Peeling force (mN / 50 mm) 30 30 50 30 60 35 Solvent resistance as an indicator of haze change Hz (A) (%) 6 10 6 10 10 6 Hz (B) (%) 6 26 10 10 12 6 ΔHz (%) 0 16 4 0 2 0 Solvent resistance as an indicator of surface roughness Surface roughness Sa (A) (nm) 70 9 5 10 6 5 Surface roughness Sa (B) (nm) 70 20 9 10 7 5 ΔSa (nm) 0 11 4 0 1 0 Removal of layer X and layer Y Removal methods Water wash Water wash Water wash Water wash Water wash Water wash Contact angle (°) of the removed water 70 70 94 75 72 98 Reuse Reuse methods Melt extrusion Melt extrusion Melt extrusion Melt extrusion Melt extrusion Melt extrusion IV(R) - 0.59 0.51 0.59 0.60 - Removability of layers X and Y after hydrothermal treatment Removal methods Water wash Water wash Water wash Water wash Water wash Water wash Contact angle (°) of the removed water 97 70 95 75 72 98

[0186] Furthermore, regarding the embodiments, in the event of any inconsistency between the description in the specification and the description in the table, the description in the table shall prevail. [Industrial Applicability]

[0187] The laminated polyester film of the present invention exhibits excellent solvent resistance in subsequent steps and excellent removability of layers other than the polyester film. Furthermore, by using layer Y of the present invention as a water-repellent material, it can be preferably used as a release film in the manufacturing process of multilayer ceramic capacitors (MLCCs) where the dielectric paste is the release material. Additionally, since the polyester film can be easily recycled from the release film used in the MLCC manufacturing process, it can be easily reused as a raw material for melt-forming. [Simplified Explanation of the Diagram]

[0012] None

Claims

1. A laminated polyester film comprising a polyester film and a layer X satisfying the following conditions, said layer X comprising a resin having a sulfonate-modified polyvinyl alcohol backbone: Condition 1: 20 ≦ γXP ≦ 45 Condition 2: 3.0 ≦ γXH ≦ 10 γXP (mN / m): polar component of the surface free energy of layer X γXH (mN / m): hydrogen bond component of the surface free energy of layer X 2. The laminated polyester film as claimed in claim 1, having layers Y, X and polyester film in sequence satisfying the following conditions, for demolding purposes of setting a demolding layer on the surface of layer Y opposite to the surface in contact with layer X and peeling the demolding layer off from layer Y, Condition 9: 80≦HY(1)≦120 Condition 10: 1≦|HY(1)-HY(20)|≦90 HY(1) (°): the contact angle of water after 1 second after contact with layer Y HY(20) (°): the contact angle of water after 20 seconds after contact with layer Y.

3. A method for manufacturing a polyester film, comprising at least: Using a laminated polyester film as described in claim 1, having sequentially a demolding layer, layer Y, layer X, and a polyester film containing recycled polyester raw material, the steps of peeling the demolding layer from layer Y; and removing layer Y from the film from which the demolding layer has been peeled off. The process includes the step of manufacturing recycled raw materials from the film after removing the demolded layer and layer Y, and further includes the step of using the recycled raw materials to form a film.

4. A laminated polyester film comprising a polyester film and a layer X, wherein the laminated polyester film, the layer X contains a resin having a sulfonate-modified polyvinyl alcohol backbone, wherein the sulfonate-based copolymerization amount of the resin having the sulfonate-modified polyvinyl alcohol backbone is 0.1 mol% or more and 10 mol% or less, and the average degree of polymerization of the layer X is determined by the method described in JIS K 6726 (1994) to be 200 or more and 2400 or less, and the degree of saponification of the layer X is determined by the method described in JIS K 6726 (1994) to be 30 or more and 97 or less.

5. The laminated polyester film as claimed in claim 1, having a layer X satisfying the following conditions: Condition 1': 20 ≦ γXP ≦ 41 Condition 2': 3.0 ≦ γXH ≦ 10 γXP (mN / m): polar component of the surface free energy of layer X γXH (mN / m): hydrogen bond component of the surface free energy of layer X 6. The laminated polyester film as claimed in claim 1, wherein the thickness xa (nm) of the layer X and the roughness RzjisB (nm) of the surface of the polyester film opposite to the surface (surface B) having the layer X satisfy the following condition: Condition 3: 1.0 ≦ RzjisB / xa ≦ 20.0 xa (nm): thickness of layer X.

7. The laminated polyester film as claimed in claim 1, wherein the thickness xa (nm) of the layer X and the surface roughness RzjisX (nm) of the layer X satisfy the following condition: Condition 7: 0.01 ≦ RzjisX / xa ≦ 3.

0.

8. The laminated polyester film as claimed in claim 1, wherein the thickness xa of layer X is 10 nm or more and 500 nm or less.

9. The laminated polyester film as claimed in claim 1, wherein the water contact angles HX(1) (°) and HX(20) (°) of layer X satisfy the following conditions: Condition 8: 5≦|HX(1)-HX(20)|≦60 HX(1) (°): the contact angle of water after 1 second after contact with layer X HX(20) (°): the contact angle of water after 20 seconds after contact with layer X 10. The laminated polyester film as claimed in claim 1, wherein the crystallinity of layer X is 14% or more and 40% or less.

11. The laminated polyester film as claimed in claim 10, wherein the crystallinity of layer X is greater than 31% and less than 40%.

12. The laminated polyester film as claimed in claim 1, wherein layer X comprises a resin with a degree of polymerization greater than 200.

13. The laminated polyester film as claimed in claim 2, wherein layer Y satisfies the following conditions: Condition 9': 100≦HY(1)≦110 Condition 10': 1≦|HY(1)-HY(20)|≦77 HY(1) (°): the contact angle of water after 1 second after contact with layer Y HY(20) (°): the contact angle of water after 20 seconds after contact with layer Y 14. The laminated polyester film as claimed in claim 13, wherein the solvent durability of the surface of layer Y, determined by the following method, is 5% or more and 100% or less, [Method for determining solvent durability] Testing machine: Vibration tester (friction tester type II as described in Japanese Industrial Standard L 0849 (2013)) Friction component: a mixed solvent of toluene and ethanol (mass ratio 1:1) impregnated in cotton cloth (wide fine cotton cloth No. 3) Load: 1 kg Number of cycles: 30 cycles Solvent durability (%) = F(A) / F(B)×100 F(A): peel force of the surface of layer Y F(B): peel force of the surface of layer Y after the solvent impregnation cloth wiping test 15. The laminated polyester film as claimed in claim 2, wherein the hydrogen bonding component γYH of the surface free energy of layer Y is 1.5 or more and 10 or less.

16. The laminated polyester film as claimed in claim 2, for use in removing layers X and Y after the release layer has been peeled off from layer Y.

17. The laminated polyester film as claimed in claim 16, for the purpose of reusing a laminated polyester film from which layers X and Y have been removed.

18. The laminated polyester film as claimed in claim 2, wherein the release layer is a ceramic green sheet with barium titanate as the main component.

19. A method for manufacturing a laminated polyester film as claimed in claim 3, wherein the polyester film comprising recycled polyester raw material has a laminated structure of three or more layers, the laminated structure having a layer (A layer) constituting an A surface as one surface of the polyester film, a layer (B layer) constituting a B surface as another surface, and a layer (C layer) having no surface.

20. A method of manufacturing a polyester film as claimed in claim 19, wherein the C layer of the polyester film comprising recycled polyester raw material comprises recycled polyester raw material.