Laminated film

Abstract

The present invention provides a laminated film that achieves both suppression of lifting and peeling of the surface layer, which is formed by coating the resin layer of the laminated film, and easy peelability, and further provides recoatability to the surface layer when it is peeled off. [Solution] A laminated film having a resin layer containing a long-chain alkyl group resin (A) on at least one side of a polyester resin base layer, wherein the tape peeling force is 2.0 N / 50 mm or more and 12.0 N / 50 mm or less, and the residual adhesion rate is 50% or more and 95% or less.

Description

[Technical Field]

[0001] The present invention relates to a laminated film having a resin layer on at least one side of a resin substrate. [Background technology]

[0002] Plastic films are widely used as base films in many applications, such as magnetic recording materials and packaging materials, due to their excellent mechanical properties, electrical properties, dimensional stability, transparency, and chemical resistance. Furthermore, plastic films having a resin layer with excellent release properties on at least one outermost surface are often used as process films (hereinafter sometimes referred to as release films) as protective films for adhesive layers in adhesive products, and as carrier films used in the production and processing of components for electronic parts and batteries. For example, when a release film is used as a process film in the manufacture of printed circuit boards, it is used as an insulating release film, in which an insulating layer is formed on the resin layer of the release film. Subsequently, the insulating release film is laminated (layered) onto a core layer, and the release film is peeled off to obtain a laminate for printed circuit boards. In subsequent processes, surface processing such as copper plating or via processing is performed on the surface from which the release film was peeled off. Furthermore, in fields such as automobiles, furniture, and building materials, a method is sometimes employed to give the surface of a product an aesthetically pleasing design by applying another coating layer to the release film to form a laminate, then transferring the laminated coating layer to the mating material, and finally laminating a topcoat layer on the peeled surface of the transferred coating layer to provide color, gloss, weather resistance, and stain resistance (hereinafter, the coating layers laminated to the insulating layer and release film are collectively referred to as surface layers). In these processing steps, it is required that immediately after applying the coating liquid containing the resin composition for forming the surface layer to the release film and dispersing the solvent, the resin layer of the release film and the surface layer adhere closely together at the interface, and that the surface layer does not lift or peel off during the transport process. On the other hand, in the subsequent process of peeling the surface layer from the release film, it is necessary that the two can be easily separated (light peeling).

[0003] For use as release films in the production and processing of components for electronic parts and batteries, studies are being conducted on using release agents that do not contain silicone compounds, such as long-chain alkyl group-containing resins, olefin resins, fluorine compounds, and wax-based compounds, with long-chain alkyl group-containing resins being particularly important (see, for example, Patent Documents 1 to 5). [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2004-351626 [Patent Document 2] Japanese Patent Publication No. 2014-151481 [Patent Document 3] Japanese Patent Publication No. 2004-230772 [Patent Document 4] Japanese Patent Publication No. 2015-199329 [Patent Document 5] Japanese Patent Publication No. 2020-152095 [Overview of the project] [Problems that the invention aims to solve]

[0005] When the release film of the present invention is used, for example, as a process film in the manufacture of printed circuit boards, copper plating is performed on the surface of the peeled surface layer that was in contact with the release film. Therefore, it is necessary to suppress the migration of low surface free energy components, such as release agents and silicone materials, and maintain surface processability (recoatability).

[0006] A release film containing a long-chain alkyl group-containing resin, which is a representative example of a release film not containing a silicone compound, generally tends to have heavy peeling compared to a release film containing a silicone compound. Therefore, for example, when light peeling is achieved by methods such as increasing the blending amount of a release agent or using a fluorine-based release agent, floating or peeling may occur on the surface layer in the conveyance process before the peeling process, or there is a problem that the low surface free energy component of the release film migrates to the surface layer after peeling, deteriorating the recoatability.

[0007] For example, when the inventors verified the film described in Patent Document 1, it was found that significant heavy peeling occurred when the surface layer was peeled from the laminated film. Also, when a long-chain alkyl group-containing resin and a crosslinking agent are used in combination as in the films described in Patent Documents 2 and 3, or when a long-chain alkyl acrylate resin and a melamine resin are used in combination as in Patent Document 4, although light peeling is achieved, the surface layer laminated on these release films may float in the conveyance process, reducing the yield. Furthermore, in the release film of Patent Document 5, although floating in the conveyance process does not occur and the peelability of the surface layer is not a problem, it has been clarified that the migration of the release agent component and the fluorine-based surfactant component to the surface layer deteriorates the recoatability of the surface layer.

[0008] Therefore, an object of the present invention is to solve the above drawbacks, suppress the floating and peeling of the surface layer provided on the resin layer of the release film, and provide a laminated film that can impart light peelability and recoatability to the surface layer when peeling the surface layer from the release film.

Means for Solving the Problems

[0009] To solve the above problems, the present invention has the following configuration. That is, the laminated film for solving the above problems is [1] A laminated film having a resin layer containing a long-chain alkyl group-containing resin (A) on at least one side of a polyester resin base material layer, with a tape peel strength of 2.0 N / 50 mm or more and 12.0 N / 50 mm or less, and a residual adhesion rate of 50% or more and 95% or less. [2] The laminated film according to [1], wherein the receding contact angle of the surface of the resin layer with respect to water is 50° or more and 85° or less. [3] When the peak intensity of the fragment of the positive ion showing the maximum intensity detected by time-of-flight secondary ion mass spectrometry on the surface of the resin layer is M + , and Si / M when the peak intensity of the fragment of the positive ion derived from polydimethylsiloxane is Si + is less than 0.01, the laminated film according to [1] or [2]. [4] When the peak intensity of the fragment of the negative ion showing the maximum intensity detected by time-of-flight secondary ion mass spectrometry on the surface of the resin layer is M - , and Ff / M when the peak intensity of the negative ion (F - ) derived from the fluorine element is Ff - is less than 0.01, the laminated film according to any one of [1] to [3]. [5] The laminated film according to any one of [1] to [4], wherein the resin layer contains any one or more compounds (X) selected from the group consisting of alkylene glycol, acetylenediol, polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl ether, glycerin fatty acid ester, sorbitan fatty acid ester, sucrose fatty acid ester, polyethylene glycol fatty acid ester, and polyoxyethylene sorbitan fatty acid ester. [6] When the peak intensity of the fragment of the positive ion showing the maximum intensity detected by time-of-flight secondary ion mass spectrometry on the surface of the resin layer is M + , and the peak intensity of the fragment of the negative ion showing the maximum intensity is M - , when M + and M - , the larger absolute value is the maximum peak intensity M, and when the total peak intensity of the fragments derived from the compound (X) is Fh, Fh / M is 0.05 or more and 0.50 or less, the laminated film according to [5]. [7] The laminated film according to any one of [1] to [6], wherein the resin layer contains at least one compound (B) selected from acrylic resin, polyester resin, urethane resin, oxazoline compound, carbodiimide compound, and melamine resin. [8] The laminated film according to [7], wherein the mass ratio of the long-chain alkyl group-containing resin (A) to the compound (B) in the resin layer, i.e., the long-chain alkyl group-containing resin (A) / compound (B), is 5 / 95 or more and 30 / 70 or less. [9] The laminated film according to any one of [1] to [8], wherein the arithmetic mean height Sa of the laminated film surface opposite to the surface having the resin layer is 1.0 nm or more and 30.0 nm or less.

[10] The laminated film according to any one of [1] to [9], wherein the polyester resin substrate layer comprises at least one of biomass raw materials and recycled raw materials. A laminate for surface layer transfer, wherein a surface layer is further laminated on the surface of the resin layer of the laminated film described in any of [1] to

[10] .

[12] A method for producing a laminated film according to any one of [1] to

[10] , comprising the steps of applying a coating composition containing the long-chain alkyl group resin (A) to at least one side of a polyester film before crystal orientation is completed, stretching it in at least one axial direction, and then heat-treating it to complete the crystal orientation of the polyester film. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a laminated film that suppresses lifting and peeling of the surface layer provided on the resin layer of the release film, and further provides easy peelability and recoatability to the surface layer when peeling the surface layer from the release film. [Brief explanation of the drawing]

[0011] [Figure 1] Schematic diagram illustrating the estimated mechanism of surface layer recoating. [Modes for carrying out the invention]

[0012] The laminated film of the present invention will be described in detail below.

[0013] The laminated film of the present invention has a resin layer containing a long-chain alkyl group resin (A) on at least one side of a polyester resin substrate layer, and is a laminated film having a tape peel strength of 2.0 N / 50 mm to 12.0 N / 50 mm and a residual adhesion rate of 50% to 95%. First, the meaning of these physical properties and examples of control methods will be explained.

[0014] Tape peeling force is an indicator of the interaction between the resin layer and the surface layer. Reducing the interaction between the resin layer and the surface layer makes it possible to peel the surface layer from the resin layer with less force. As a result of diligent research by the inventors, we found a correlation between the lifting and peeling behavior of the surface layer of the present invention before peeling it from the laminated film and the tape peeling force (the peeling force between the resin layer of the laminated film of the present invention and the acrylic adhesive tape).

[0015] The peeling force between the resin layer and the surface layer of the laminated film of the present invention is thought to depend on the tape peeling force defined in this application, that is, the strength of the interaction between the resin layer of the laminated film of the present invention and the acrylic adhesive tape. In other words, a stronger interaction results in a stronger peeling force (heavy peeling (difficult to peel)), and a weaker interaction results in a weaker peeling force (light peeling (easy to peel)). The interaction here refers to intermolecular forces due to hydrogen bonding and hydrophobic interactions, as well as values ​​determined by the surface free energy of each layer and its difference. Furthermore, when detected as peeling force, it is affected by the thickness and elastic modulus of the layers depending on the direction of peeling.

[0016] In this invention, the tape peeling force can be measured by the following method. First, an acrylic adhesive tape (Nitto Denko Corporation, No. 31B tape, 19 mm wide, total thickness 0.053 mm) is bonded onto the resin layer of the laminated film of this invention, and a 2 kgf roller is passed over it once. After that, the laminated film with the bonded tape is left to stand for 24 hours in an environment of 25°C and 65% RH, and the peeling load obtained when peeling the tape using a Shimadzu Corporation universal testing machine "Autograph AG-1S" at a peeling angle of 180° and a tensile speed of 300 mm / min is defined as the tape peeling force. The specific method for measuring the tape peeling force will be described later. Note that tapes with equivalent adhesive properties and measuring devices capable of similar measurements may be used.

[0017] If the tape peeling force exceeds 12.0 N / 50 mm, the surface layer may rupture without separating from the resin layer during the surface layer peeling process, reducing the yield. On the other hand, if the tape peeling force is below 2.0 N / 50 mm, the surface layer may lift or peel off during the transport process before peeling the surface layer from the laminated film.

[0018] The laminated film of the present invention preferably has a lower limit of tape peeling force of 4.0 N / 50 mm or more, and more preferably 6.0 N / 50 mm or more. The upper limit of the tape peeling force is preferably 11.5 N / 50 mm or less, and more preferably 11.0 N / 50 mm or less. By setting the tape peeling force within the above preferred range, lifting and peeling of the surface layer during the transport process can be suppressed, while the surface layer can be peeled off from the release film with light force during the peeling process.

[0019] In the laminated film of the present invention, methods for achieving the tape peeling force within the above range include using a long-chain alkyl group-containing resin (A) as a release agent, including a compound (B) described later as a component other than the long-chain alkyl group-containing resin (A) and controlling their composition ratio to a preferred range described later, using a material that does not contain fluorine or silicone compounds, and setting the surface roughness on the side opposite to the side with the resin layer to a preferred range described later. Note that not all of these methods are essential and can be used in combination as appropriate.

[0020] Furthermore, the laminated film of the present invention must have a residual adhesion rate of 50% to 95%. The residual adhesion rate is expressed as the ratio of the adhesive strength after applying and peeling off an adhesive tape from a specific material to the initial adhesive strength, and is generally used as an indicator to confirm the migration properties of components such as release agents contained in the resin layer. A detailed method for measuring the residual adhesion rate will be described later.

[0021] The inventors have found that by setting the tape peeling force within the aforementioned preferred range and the residual adhesion rate to 50% to 95%, lifting and peeling of the surface layer during the transport process can be suppressed, the peeling force of the surface layer can be reduced to light peeling, and furthermore, the surface layer can be given recoatability when peeled off from the release film.

[0022] As mentioned above, the residual adhesion rate is used as an indicator to confirm the migration of release agent components, and generally, a high residual adhesion rate, that is, low migration of release agent components, is preferred. To suppress the migration of release agent components, for example, a method is used to provide reaction sites that act as crosslinking points in the release agent, but in that case, the interaction between the resin layer and the adhesive tape decreases, resulting in a tape peeling force of less than 2.0 N / 50 mm, which may cause lifting or peeling of the surface layer during the transport process. On the other hand, in order to suppress lifting or peeling of the surface layer, it is necessary to increase the interaction between the resin layer and the surface layer, for example, a method is used to reduce low surface free energy components such as release agents, but in that case, the tape peeling force becomes 12 N / 50 mm or more, and the peeling force of the surface layer becomes heavy peeling, which may reduce the yield.

[0023] As a result of diligent research by the inventors, it was found that the residual adhesion rate is affected not only by the release agent but also by the migration of low molecular weight substances contained in the resin layer, specifically surfactants, to the surface layer. Generally, surfactants are added to paint compositions as leveling agents to impart coatability, but in the laminated film of the present invention, the surfactant contained in the resin layer migrates to the surface layer side during the process of peeling the surface layer from the resin layer, making it possible to reduce the peeling force of the surface layer and also impart recoatability to the surface layer. The reason for this is thought to be as follows.

[0024] First, surfactants have hydrophilic and hydrophobic parts within a single molecule. When applied as a paint composition and dried, forming a resin layer, the hydrophobic parts with lower surface free energy are positioned upwards (towards the exposed surface) and the hydrophilic parts downwards (towards the substrate). When the surface layer is peeled off, slight peeling occurs due to the migration of surfactant components in addition to the reduction of surface free energy by the hydrophobic parts on the surface. Furthermore, after peeling, the surfactant that has migrated to the surface layer will be positioned with the hydrophilic parts with higher surface free energy upwards (towards the exposed surface) and the hydrophobic parts downwards (towards the surface layer). As a result, hydrophilic parts are aligned on the surface of the surface layer, which is thought to impart recoatability to the surface layer. When the surface layer is peeled off, the migration of release agent components worsens the recoatability of the surface layer, so it is important to actively migrate the surfactant while suppressing the migration of release agent components. A schematic diagram representing the estimated mechanism of surface layer recoatability is shown in Figure 1.

[0025] In the laminated film of the present invention, the lower limit of the residual adhesion rate is preferably 55% or more, and more preferably 60% or more. The upper limit of the residual adhesion rate is preferably 85% or less, and more preferably 75% or less.

[0026] In the laminated film of the present invention, methods for controlling the residual adhesion rate within the above range include using a long-chain alkyl group-containing resin (A) as a release agent, including a compound (B) described later as a component other than the long-chain alkyl group-containing resin (A) and controlling their composition ratio within a preferred range described later, using a material that does not contain fluorine or silicone compounds, controlling the type and amount of surfactant within a preferred range described later, and applying high-temperature heat treatment by an in-line coating method. Note that not all of these methods are essential and can be used in combination as appropriate.

[0027] The polyester resin substrate and resin layer in the laminated film of the present invention will be described in detail below. The polyester resin substrate (hereinafter, the polyester resin substrate may be referred to as the "substrate film" or "substrate") refers to a sheet-like molded article mainly composed of polyester, and the main component refers to the resin component that is included in more than 50% by mass when the total resin constituting the film is considered to be 100% by mass. Unless otherwise specified, the definition of the main component can be interpreted in the same way.

[0028] The following describes the polyester used as the resin substrate for the laminated film of the present invention. First, polyester is a general term for polymers having repeating ester bonds in their main chain. In the resin substrate of the laminated film of the present invention, it is preferable to use a polyester whose main constituent unit is at least one of the following: ethylene terephthalate, propylene terephthalate, ethylene-2,6-naphthalate, butylene terephthalate, propylene-2,6-naphthalate, ethylene-α,β-bis(2-chlorophenoxy)ethane-4,4'-dicarboxylate, etc. Here, the main constituent unit refers to the constituent unit that is present in the largest amount on a molar basis in the molecular chain constituting the resin, and a specific example is the ethylene terephthalate unit in polyethylene terephthalate. Note that one type of polyester may be used, or a mixture of multiple types may be used.

[0029] The polyester film using the above-mentioned polyester is preferably a biaxially oriented polyester film. A biaxially oriented polyester film is a polyester film in which molecules are oriented in two orthogonal directions, and this shows a biaxial orientation pattern in wide-angle X-ray diffraction. A biaxially oriented polyester film is generally obtained by stretching an unstretched polyester sheet by about 2.5 to 5.0 times in the longitudinal direction, which is the direction in which the film runs during the manufacturing process, and in the width direction perpendicular to the longitudinal direction within the film plane, and then heat-treating it to complete the crystal orientation. Biaxially oriented polyester films have excellent thermal stability, especially dimensional stability and mechanical strength, and also have good flatness.

[0030] Furthermore, various additives, such as inorganic particles, antioxidants, heat stabilizers, weather stabilizers, ultraviolet absorbers, organic lubricants, pigments, dyes, organic or inorganic fine particles, fillers, antistatic agents, and nucleating agents, may be added to the polyester film in an amount that does not impair its properties.

[0031] The thickness of the polyester film is not particularly limited and is selected appropriately depending on the application and type, but from the viewpoint of mechanical strength and handling properties, it is usually preferably 10 to 500 μm, more preferably 15 to 250 μm, and even more preferably 20 to 100 μm. The polyester film has a certain thickness to ensure strength, and conversely, handling properties can be ensured by not making the thickness excessively large.

[0032] In the laminated film of the present invention, it is preferable that the arithmetic mean height Sa of the laminated film surface opposite to the side having the resin layer is 1.0 nm or more and 30.0 nm or less. Setting Sa to 1.0 nm or more results in a very high surface smoothness, which increases the coefficient of friction with the resin layer and prevents wrinkles from forming when the laminated film is wound into a roll. Setting Sa to 30 nm or less results in a back attack when the laminated film is wound into a roll, where the uneven shape of the laminated film surface opposite to the side having the resin layer is transferred to the resin layer, and the anchoring effect prevents the surface layer from peeling off completely.

[0033] The laminated film of the present invention preferably has a lower limit of 3.0 nm or more, and more preferably 5.0 nm or more, for the arithmetic surface roughness Sa of the laminated film surface opposite to the side having the resin layer. Furthermore, the upper limit is preferably 20 nm or less, and even more preferably 10 nm or less.

[0034] The method for controlling the Sa of the laminated film of the present invention is not particularly limited, but for example, methods such as using a raw material containing particle material in the film-forming process of polyester film, using particle-containing polyester, scraping the surface of the polyester film by methods such as high-voltage discharge or plasma, or coating the surface opposite to the surface having the resin layer with a coating composition to which particles have been added can be used. In the present invention, when coating the surface opposite to the surface having the resin layer with a coating composition to which particles have been added can be used, suitable particle components to be used are oxide fine particles of elements located on the diagonal line connecting boron (B), silicon (Si), arsenic (As), tellurium (Te), and astatine (At) on the periodic table, and to the left of the said diagonal line.

[0035] Examples of such particulate components include SiO2, TiO2, ZrO2, ZnO, CeO2, SnO2, Sb2O5, indium-doped tin oxide (ITO), phosphorus-doped tin oxide (PTO), Y2O3, La2O3, and Al2O3.

[0036] These particulate components may be used individually or in combination of two or more. From the viewpoint of dispersion stability and refractive index, SiO2, TiO2, and ZrO2 are particularly preferred.

[0037] In the laminated film of the present invention, when applying a coating composition containing particles to the laminated film surface opposite to the surface having the resin layer, the particle component used preferably has a number-average particle diameter of 3 nm to 1000 nm. More preferably, it is 20 nm to 600 nm, and even more preferably 50 nm to 300 nm. If the number-average particle diameter of the particle component is too small, the van der Waals forces between the particles become very large, making aggregation more likely. On the other hand, if the number-average particle diameter of the particle component is too large, it tends to detach from the resin layer.

[0038] The content of particulate components in the paint composition is preferably 0.5% by mass or more and 10% by mass or less relative to the total resin constituting the paint composition. More preferably, it is 1% by mass or more and 7% by mass or less, and even more preferably 2% by mass or more and 5% by mass or less.

[0039] A film using a resin substrate containing particulate material may be a single-layer film, a composite film produced by co-extrusion, or a composite film obtained by laminating the resulting films using various methods. Examples of films having a two-layer laminated structure include one consisting of layer A and layer B, while examples of films having a three-layer laminated structure include a two-type three-layer configuration of layer A / layer B / layer A, or a three-type three-layer configuration of layer A / layer B / layer C. Examples of films having a four-layer or more laminated structure include one in which the intermediate layer has a laminated structure. The same layer configuration can be used whether a polyester film or another type of film is used as the resin substrate.

[0040] The slippery particles may be either inorganic or organic. Examples of inorganic slippery particles include calcium carbonate, agglomerated alumina, aluminum silicate, silicon oxide, barium sulfate, mica, clay, and talc. Examples of organic slippery particles include polyimide resins, olefins or modified olefin resins, crosslinked polystyrene resins, and silicone resins. However, when wound into a roll, particles contained in the outermost layer opposite the resin layer may detach and transfer to the resin layer, potentially reducing the smoothness, quality, and peelability of the resin layer. In addition, the migration of particles to the surface layer on the resin layer side may worsen the performance of the surface layer. Therefore, it is preferable to use organic particles that easily enhance affinity with the resin substrate for the particles contained in the film. Furthermore, from the viewpoint of suppressing the detachment of slippery particles, a method of modifying the particle surface with a surfactant or the like to improve affinity with the resin components of the resin substrate containing the particles is also preferably employed. In particular, when the resin substrate is polyester, crosslinked polystyrene particles made of styrene-divinylbenzene copolymer, adjusted by emulsion polymerization, can be preferably used. Such cross-linked polystyrene particles are preferable because their particle shape is close to a perfect sphere, their particle size distribution is more uniform, and it is possible to achieve uniform protrusion formation.

[0041] Furthermore, the calcium element content in the laminated film of the present invention is preferably 300 ppm (by mass, the same applies hereinafter) or less. A preferred content is 150 ppm or less, and more preferably 10 ppm or less. Particles formed by calcium in polyester have lower solubility in polyester compared to particles formed by organic particles, etc., and tend to form coarse aggregates even in trace amounts. By limiting the calcium element content to a specified amount or less, it is possible to suppress the generation of coarse aggregates and the shedding of particles.

[0042] From the viewpoint of reducing environmental impact, it is preferable that the resin substrate of the present invention contains at least one of biomass raw materials and recycled raw materials. To make such a laminated film, it is preferable to use a polyester film containing at least one of biomass raw materials and recycled raw materials as the resin substrate. Here, biomass refers to organic compounds derived from plants that are photosynthesized from carbon dioxide and water. When biomass is burned, it usually turns back into carbon dioxide and water, so biomass can be used as a so-called carbon-neutral renewable energy source. Furthermore, biomass raw materials refer to polyester containing constituent units derived from biomass.

[0043] When the proportion of plant-derived carbon to the total carbon is defined as the biomass percentage, for example, in an ethylene terephthalate unit, if only the ethylene glycol component is entirely plant-derived, the biomass percentage is theoretically 20%. To increase the biomass percentage further, the terephthalic acid must also be plant-derived, which would have a greater effect on reducing environmental impact but would increase production costs. For the ethylene glycol and terephthalic acid components, a combination of petroleum-derived and plant-derived components may be used.

[0044] The lower limit of the biomass content of the polyester constituting the laminated film is preferably 5%, more preferably 10%, and even more preferably 13%, from the viewpoint of exhibiting an environmental load reduction effect. An environmental load reduction effect can be expected if the biomass content is 5% or higher. On the other hand, if only environmental load reduction is considered, a higher upper limit for the biomass content is preferable, with 100% being the upper limit. However, from the viewpoint of balancing production costs and environmental load reduction, a practical upper limit of 20% for the biomass content is preferable.

[0045] Furthermore, a known method for analyzing the presence or absence of biomass raw materials is, for example, the carbon isotope analysis described on the website of the Japan Bioplastics Association (http: / / www.jbpaweb.net / bp / ). 14 One possible method is to use C).

[0046] Recycled raw materials are raw materials obtained by recovering and reusing polyester that has been used in chemical products once or multiple times. Examples of recycled raw materials in the laminated film of the present invention include uncoated portions at both ends in the width direction that are cut and removed during the manufacturing process of the laminated film of the present invention, recovered products of other polyester films, and polyester products that have been distributed in forms other than film, such as bottles.

[0047] In the laminated film of the present invention, it is preferable that the proportion of recycled polyester (recycled raw material) in 100% by mass of polyester contained in the laminated film (recycling rate) be 90% by mass or less. By limiting the use of recycled polyester to 90% by mass or less, the amount of highly crystalline polyester that has once become a chemical product is reduced, thereby reducing the decrease in thermal properties and transparency, as well as discoloration, of the resulting laminated film.

[0048] The laminated film of the present invention has a resin layer on at least one surface of a resin substrate. Here, the resin layer is a layer mainly composed of resin and is located on the outermost surface. The preferred form of the resin layer of the laminated film of the present invention will be described below.

[0049] In the laminated film of the present invention, the receding contact angle with respect to water of the resin layer surface is preferably 50° to 85°. The receding contact angle is preferably 55° to 85°, and more preferably 60° to 75°. Furthermore, by setting the receding contact angle with respect to water of the resin layer surface within the above range, the surface layer can be recoated when the surface layer is peeled off.

[0050] Methods for achieving the above-mentioned receding contact angle with water include, for example, using a long-chain alkyl group-containing resin (A) as a mold release agent, including a compound (B) described later as a component other than the long-chain alkyl group-containing resin (A) and controlling their composition ratio to a preferred range described later, using a material that does not contain fluorine or silicone compounds, controlling the type and amount of surfactant to a preferred range described later, and applying high-temperature heat treatment by an in-line coating method. Note that not all of these methods are essential and can be used in combination as appropriate.

[0051] In the laminated film of the present invention, the resin layer, when used as a release film, prevents contamination of the surface layer by silicone and suppresses deterioration of recoatability, by setting the peak intensity of the positive ion fragment that exhibits maximum intensity to M. + When the peak intensity of the positive ion fragment derived from polydimethylsiloxane is taken as Si, the Si / M + It is preferable that the value is less than 0.01.

[0052] The ratio of peak intensities in time-of-flight secondary ion mass spectrometry (Si / M) + When the above preferred range is met, it means that there are few components derived from polydimethylsiloxane in the resin layer, which suppresses the migration of release agent components when peeling off the surface layer provided on the resin layer of the laminated film of the present invention, and suppresses deterioration of the recoatability of the surface layer. From the viewpoint of feasibility, Si / M + The lower limit is 0.001 (measurement lower limit). Si / M of the resin layer of the laminated film of the present invention + One method for achieving the above range is to use a mold release agent that does not contain silicone.

[0053] In the laminated film of the present invention, the resin layer is determined by time-of-flight secondary ion mass spectrometry of the surface of the resin layer, and the peak intensity of the negative ion fragment exhibiting maximum intensity is M - , negative ions (F) derived from the element fluorine - When the peak intensity of ) is Ff, Ff / M - It is preferable that the value is less than 0.01.

[0054] The ratio of peak intensities Ff / M in time-of-flight secondary ion mass spectrometry. - When the above preferred range is reached, it means that there are few components derived from fluorine elements in the resin layer, which suppresses the migration of low surface free energy components when peeling off the surface layer provided on the resin layer of the laminated film of the present invention, and suppresses deterioration of the recoatability of the surface layer. From the viewpoint of feasibility, Ff / M - The lower limit is 0.001 (measurement lower limit). Ff / M of the resin layer of the laminated film of the present invention - One method for achieving the above range is to use a mold release agent or surfactant that does not contain fluorine.

[0055] The thickness of the resin layer in the laminated film of the present invention is not particularly limited, but is preferably greater than 5 nm and less than 100 nm. More preferably, it is 10 nm to 80 nm, and even more preferably 15 nm to 40 nm. By setting the thickness of the resin layer within the above range, it is possible to reduce the amount of paint composition used to form the resin layer and reduce the absolute amount of components that migrate from the resin layer to the surface layer while ensuring the function of the resin layer. More specifically, a resin layer thickness greater than 5 nm makes it easier to sufficiently ensure the function of the resin layer, and a resin layer thickness of less than 100 nm can suppress the migration of the release agent from the resin layer to the surface layer.

[0056] The following describes preferred coating compositions for forming the resin layer of the laminated film of the present invention.

[0057] Examples of release agents that can be used in the resin layer of the laminated film of the present invention include long-chain alkyl resins, silicone resins, olefin resins, fluorine compounds, and wax compounds. Among these, long-chain alkyl resins are preferred because they can exhibit good release properties while suppressing component migration to the surface layer.

[0058] When using a long-chain alkyl resin as a release agent, it is preferable that it contains a reactive functional group as a side chain in addition to the long-chain alkyl group. That is, a particularly preferred form of the release agent of the present invention is a copolymer resin having a long-chain alkyl group and a reactive functional group. Examples of reactive functional groups include hydroxyl groups, carboxyl groups, amino groups, glycidyl groups, isocyanate groups, vinyl groups, acrylic groups, and methacrylic groups, but it is particularly preferable to have a hydroxyl group from the viewpoint of compatibility with water, which is a preferred solvent described later. Note that there may be one type or multiple types of reactive functional groups. By containing a functional group in the long-chain alkyl resin, the long-chain alkyl resin can be immobilized in the resin layer and migration to the surface layer can be suppressed.

[0059] Commercially available long-chain alkyl resins may be used. Specifically, the "Ashiorezin" (registered trademark) series of long-chain alkyl compounds manufactured by Ashio Industries Co., Ltd., the "Piroyl" (registered trademark) series of long-chain alkyl compounds manufactured by Lion Specialty Chemicals, and the Rezem series of aqueous dispersions of long-chain alkyl compounds manufactured by Chukyo Oils Co., Ltd. can be used.

[0060] The long-chain alkyl group-containing resin (A) used as a mold release agent preferably has an alkyl group with 12 or more carbon atoms, and more preferably has an alkyl group with 16 or more carbon atoms. By increasing the number of carbon atoms in the alkyl group to 12 or more, the hydrophobicity is enhanced, allowing it to exhibit sufficient performance as a mold release agent. There is no particular upper limit to the number of carbon atoms in the alkyl group, but it is preferable to have 25 or fewer carbon atoms because it facilitates the manufacture of laminated films.

[0061] Furthermore, the presence or absence of alkyl groups with 12 or more carbon atoms can be evaluated from the laminated film, for example, by using the intensity of the signal corresponding to the alkyl group obtained by TOF-SIMS. In this case, by using the ion sputtering method in combination, it is possible to perform continuous measurements in the depth direction (thickness direction), and the distribution state of alkyl group-containing compounds can also be evaluated.

[0062] The laminated film of the present invention preferably contains at least one compound (B) selected from acrylic resin, polyester resin, urethane resin, oxazoline compound, carbodiimide compound, and melamine resin as a component other than the long-chain alkyl group-containing resin (A).

[0063] When using an acrylic resin as compound (B), the monomers constituting the acrylic resin are not particularly limited, but examples of monomers having a hydroxyl group include 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, and 3-methyl-3-hydroxybutyl (meth)acrylate. Examples of monomers having a carboxyl group include acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, crotonic acid, itaconic acid, citraconic acid, cinnamic acid, 2-(meth)acryloyloxyethyl succinic acid, monohydroxyethyl (meth)acrylate maleate, monohydroxyethyl (meth)acrylate fumarate, monohydroxyethyl (meth)acrylate phthalate, 1,2-dicarboxycyclohexane monohydroxyethyl (meth)acrylate, (meth)acrylate dimers, and ω-carboxy-polycaprolactone mono(meth)acrylate. These monomers may be polymerized individually or copolymerized in combination with other monomers.

[0064] When using a polyester resin as compound (B), it is preferable to use one having ester bonds in the main chain or side chains, and obtained by polycondensation of a dicarboxylic acid and a diol. As the dicarboxylic acid used as the raw material for the polyester resin, aromatic, aliphatic, and alicyclic dicarboxylic acids can be used. As aromatic dicarboxylic acids, terephthalic acid, isophthalic acid, orthophthalic acid, phthalic acid, 2,5-dimethylterephthalic acid, 1,4-naphthalenedicarboxylic acid, biphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,2-bisphenoxyethane-p-p'-dicarboxylic acid, phenylindanedicarboxylic acid, etc. As aliphatic and alicyclic dicarboxylic acids, succinic acid, adipic acid, sebacic acid, azelaic acid, dodecanedionic acid, dimer acid, 1,3-cyclopentanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, etc., and their ester-forming derivatives can be used. Note that these may be used individually or in combination of multiple types.

[0065] The diol components used as raw materials for the polyester resin include ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 2,4-dimethyl-2-ethylhexane-1,3-diol, neopentyl glycol, 2-ethyl-2-butyl-1,3-propanediol, 2-ethyl-2-isobutyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2,2,4-trimethyl- 1,6-Hexanediol, 1,2-Cyclohexanedimethanol, 1,3-Cyclohexanedimethanol, 1,4-Cyclohexanedimethanol, 2,2,4,4-Tetramethyl-1,3-Cyclobutanediol, 4,4'-Thiodiphenol, Bisphenol A, 4,4'-Methylenediphenol, 4,4'-(2-Norbornylidene)diphenol, 4,4'-Dihydroxybiphenol, o-, m-, and p-Dihydroxybenzene, 4,4'-Isopropylidenephenol, 4,4'-Isopropylidenebinediol, Cyclopentane-1,2-Diol, Cyclohexane-1,2'-Diol, Cyclohexane-1,2-Diol, Cyclohexane-1,4-Diol, etc. can be used. These can be used individually or in combination of multiple types.

[0066] Furthermore, it is also possible to use modified polyester copolymers, such as block copolymers or graft copolymers modified with acrylic, urethane, epoxy, etc.

[0067] Furthermore, the urethane resin that can be used as compound (B) is preferably a resin obtained by reacting a polyhydroxy compound and a polyisocyanate compound by known polymerization methods for urethane resins, such as emulsion polymerization or suspension polymerization.

[0068] Examples of polyhydroxy compounds include polyethylene glycol, polypropylene glycol, polyethylene-propylene glycol, polytetramethylene glycol, hexamethylene glycol, tetramethylene glycol, 1,5-pentanediol, diethylene glycol, triethylene glycol, polycaptolactone, polyhexamethylene adipate, polyhexamethylene sebacate, polytetramethylene adipate, polytetramethylene sebacate, trimethylolpropane, trimethylolethane, pentaerythritol, polycarbonate diol, and glycerin.

[0069] Examples of polyisocyanate compounds that can be used include hexamethylene diisocyanate, diphenylmethane diisocyanate, tolylene diisocyanate, isophorone diisocyanate, adducts of tolylene diisocyanate and trimethylenepropane, and adducts of hexamethylene diisocyanate and trimethylolethane.

[0070] Examples of melamine resins that can be used as compound (B) include melamine, methylolated melamine derivatives obtained by condensing melamine with formaldehyde, compounds partially or completely etherified by reacting methylolated melamine with a lower alcohol, and mixtures thereof. The melamine resin may be a monomer or a condensate consisting of two or more polymers, or a mixture thereof. Examples of lower alcohols used for etherification include methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butanol, and isobutanol. Functional groups include imino groups, methylol groups, or alkoxymethyl groups such as methoxymethyl groups and butoxymethyl groups in one molecule, and include imino-type methylated melamine resins, methylol-type melamine resins, methylol-type methylated melamine resins, and fully alkyl-type methylated melamine resins. Among these, methylolated melamine resins are most preferably used. A commercially available methylolated melamine resin may be used, for example, Sanwa Chemical Co., Ltd.'s "Nikarac" (registered trademark) MW-035, MW-30M, MW-30MLF, etc. are suitable.

[0071] Furthermore, the oxazoline compound that can be used as compound (B) is preferably one that has an oxazoline group as a functional group in the compound, and is composed of an oxazoline group-containing copolymer obtained by copolymerizing at least one monomer containing an oxazoline group with at least one other monomer.

[0072] Examples of monomers containing an oxazoline group include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, and 2-isopropenyl-5-ethyl-2-oxazoline. One or more of these can be used as a mixture. Among these, 2-isopropenyl-2-oxazoline is preferred because it is readily available industrially.

[0073] In oxazoline compounds, at least one other monomer used with a monomer containing an oxazoline group is a monomer copolymerizable with the oxazoline group-containing monomer, such as acrylic acid esters or methacrylic acid esters such as methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, and 2-ethylhexyl methacrylate; unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, and maleic acid; acrylonitrile; and methacrylonitrile. Any unsaturated nitriles, unsaturated amides such as acrylamide, methacrylamide, N-methylolacrylamide, and N-methylolmethacrylamide, vinyl esters such as vinyl acetate and vinyl propionate, vinyl ethers such as methyl vinyl ether and ethyl vinyl ether, olefins such as ethylene and propylene, halogen-containing α,β-unsaturated monomers such as vinyl chloride, vinylidene chloride, and vinyl fluoride, and α,β-unsaturated aromatic monomers such as styrene and α-methylstyrene can be used, and one or more of these can be used as mixtures.

[0074] Furthermore, the carbodiimide compound that can be used as compound (B) is a compound that has one or more carbodiimide groups or cyanamide groups in a tautomer relationship therewith as functional groups within its molecule. Specific examples of such carbodiimide compounds include dicyclohexylmethanecarbodiimide, dicyclohexylcarbodiimide, tetramethylxylylenecarbodiimide, and urea-modified carbodiimide, and one or more of these can be used as a mixture of two or more. Commercially available carbodiimide compounds may also be used; for example, Nisshinbo Chemical Co., Ltd.'s "Carbodilite" (registered trademark) V-04, V-02, V-02-L2, SV-02, etc., are preferred.

[0075] Furthermore, the coating composition for forming the resin layer of the laminated film of the present invention may also contain a crosslinking catalyst. By including a crosslinking catalyst, the crosslinking reaction during heat treatment is made more efficient, resulting in a higher degree of crosslinking of the resin layer. As a result, when a surface layer is applied to the resin layer, penetration of the surface layer into the resin layer becomes less likely, making it easier to achieve good peelability of the surface layer. As crosslinking catalysts, for example, acidic catalysts such as p-toluenesulfonic acid and dodecylbenzenesulfonic acid, or amine salt-based catalysts can be used. Commercially available catalysts may be used, and for example, "NACURE" (registered trademark) 5528, 5928, and 2500 manufactured by Kusumoto Chemical Co., Ltd. are preferred.

[0076] In the coating composition for forming the resin layer in the laminated film of the present invention, there is a preferred content for the release agent. Specifically, when the total of the long-chain alkyl group-containing resin (A) and compound (B) is set to 100, the mass ratio of the long-chain alkyl group-containing resin (A) to compound (B), i.e., the long-chain alkyl group-containing resin (A) / compound (B), is preferably in the range of 5 / 95 to 30 / 70. More preferably, the mass ratio of the long-chain alkyl group-containing resin (A) to compound (B) is in the range of 5 / 95 to 20 / 80, and even more preferably 5 / 95 to 10 / 90. By setting the mass ratio of the long-chain alkyl group-containing resin (A) to compound (B) within the above preferred range, it is possible to prevent the release agent component from migrating from the resin layer to the surface layer and to prevent deterioration of the recoatability of the surface layer.

[0077] The paint composition may contain a solvent or dispersion medium (hereinafter simply referred to as "solvent") to the extent that it does not impair the function of the resin layer. That is, various components may be dissolved or dispersed in a solvent to form a paint composition, which may then be applied to a polyester film that will serve as the resin substrate. When this method is employed, a laminated film with a resin layer can be obtained by drying the solvent after application and then heating the film.

[0078] In the coating composition for forming the resin layer of the laminated film of the present invention, it is preferable to use an aqueous solvent as the solvent. Here, an aqueous solvent refers to water, or a mixture of water as the main component with water and an organic solvent that is soluble in water, such as alcohols such as methanol, ethanol, isopropyl alcohol, and butanol, ketones such as acetone and methyl ethyl ketone, and glycols such as ethylene glycol, diethylene glycol, and propylene glycol. Using an aqueous solvent suppresses the rapid evaporation of the solvent during the heating process, which not only allows for the formation of a uniform resin layer but also has advantages in terms of environmental impact.

[0079] The coating composition for forming the resin layer of the laminated film of the present invention can be prepared by mixing and stirring a release agent, binder resin, crosslinking agent, and aqueous solvent in any order and in any weight ratio as needed, after dispersing or solubilizing them in water as necessary. Then, various additives such as lubricants, organic particles, surfactants, antioxidants, and catalysts can be mixed and stirred in any order as needed, to the extent that they do not degrade the properties of the resin layer. Methods of mixing and stirring include shaking the container by hand, stirring with a magnetic stirrer or stirring blades, ultrasonic irradiation, vibration dispersion, etc.

[0080] Of these, the surfactant is formed from a composition containing a surfactant in order to improve the uniformity of the coating film. Examples of surfactants include silicone-based surfactants, fluorine-based surfactants having perfluoroalkyl groups, and hydrocarbon-based surfactants such as acetylene-based surfactants. Among these, fluorine-based surfactants having perfluoroalkyl groups are preferably not used from the viewpoint of imparting recoatability to the surface layer, which is an issue of the present invention, and from the viewpoint of regulating PFAS materials, and hydrocarbon-based surfactants are preferred.

[0081] Examples of hydrocarbon surfactants include nonionic surfactants, anionic surfactants, cationic surfactants, amphoteric surfactants, and other emulsifying and dispersing agents. These may be used individually or in combination of two or more types.

[0082] Examples of nonionic surfactants include (poly)alkylene oxide (AO) adduct type nonionic surfactants and polyhydric alcohol type nonionic surfactants. Examples of AO adduct type surfactants include (poly)ethylene oxide (EO) adducts of aliphatic alcohols having 10 to 20 carbon atoms, EO adducts of phenols, EO adducts of nonylphenols, EO adducts of alkylamines having 8 to 22 carbon atoms, and EO adducts of poly(oxypropylene) glycols. Examples of polyhydric alcohol type surfactants include fatty acid (8 to 24 carbon atoms) esters of polyhydric (3 to 8 or more carbon atoms) alcohols (2 to 30 carbon atoms) (e.g., glycerin monostearate, glycerin monooleate, sorbitan monolaurate, and sorbitan monooleate) and alkyl (4 to 24 carbon atoms) poly(degree of polymerization 1 to 10) glycosides. Examples of commercially available nonionic surfactants include "Naroacty" (registered trademark) CL-95 and HN-100 (product name: manufactured by Sanyo Chemical Industries, Ltd.), Risolex BW400 (product name: manufactured by Higher Alcohol Industry Co., Ltd.), "EMALEX" (registered trademark) ET-2020 (all manufactured by Nippon Emulsion Co., Ltd.), and "Surfinol" (registered trademark) 104E, 420, 440, 465, and "Dynol" (registered trademark) 604, 607 (all manufactured by Nisshin Chemical Industry Co., Ltd.).

[0083] Examples of anionic surfactants include ether carboxylic acids or salts thereof having hydrocarbon groups with 8 to 24 carbon atoms [e.g., sodium lauryl ether acetate and (poly)oxyethylene (1 to 100 added moles) sodium lauryl ether acetate]; sulfate esters or ether sulfate esters or salts thereof having hydrocarbon groups with 8 to 24 carbon atoms [e.g., sodium lauryl sulfate, (poly)oxyethylene (1 to 100 added moles) sodium lauryl sulfate, (poly)oxyethylene (1 to 100 added moles) triethanolamine lauryl sulfate and (poly)oxyethylene (1 to 100 added moles) coconut oil fatty acid monoethanolamide sulfate sodium]; sulfonates having hydrocarbon groups with 8 to 24 carbon atoms [e.g., sodium dodecylbenzenesulfonate]; hydrocarbon groups with 8 to 24 carbon atoms Examples include sulfosuccinates having one or two of these groups; phosphate esters or ether phosphate esters having hydrocarbon groups with 8 to 24 carbon atoms, or salts thereof [e.g., sodium lauryl phosphate and (poly)oxyethylene (1 to 100 moles added) sodium lauryl ether phosphate]; fatty acid salts having hydrocarbon groups with 8 to 24 carbon atoms [e.g., sodium laurate and triethanolamine laurate]; and acylated amino acid salts having hydrocarbon groups with 8 to 24 carbon atoms [e.g., sodium methyl taurate, sodium sarcosinate, triethanolamine sarcosinate, triethanolamine acyl-L-glutamate, sodium acyl-L-glutamate, and sodium lauroylmethyl-β-alanine]. Examples of commercially available anionic surfactants include "Rapizol" (registered trademark) A-90, A-80, BW-30, B-90, and C-70 (all manufactured by NOF Corporation), "NIKKOL" (registered trademark) OTP-100 (all manufactured by Nikko Chemical Co., Ltd.), "Kohakuru" (registered trademark) ON, L-40, and "Phosphanol" (registered trademark) 702 (all manufactured by Toho Chemical Industry Co., Ltd.), and "Viewlight" (registered trademark) A-5000 and SSS (all manufactured by Sanyo Chemical Industries, Ltd.).

[0084] Examples of cationic surfactants include quaternary ammonium salts [such as stearyltrimethylammonium chloride, behenyltrimethylammonium chloride, distearyldimethylammonium chloride, and lanolin fatty acid aminopropylethyldimethylammonium ethyl sulfate] and amine salts [such as diethylaminoethylamide lactate stearate, dilaurylamine hydrochloride, and oleylamine lactate].

[0085] Examples of amphoteric surfactants include betaine-type amphoteric surfactants [such as coconut oil fatty acid amidopropyl dimethylaminoacetic acid betaine, lauryl dimethylaminoacetic acid betaine, 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, lauryl hydroxysulfobetaine, and lauroylamide ethyl hydroxyethyl carboxymethyl betaine hydroxypropyl sodium phosphate] and amino acid-type amphoteric surfactants [such as β-laurylaminopropionate sodium].

[0086] In the resin layer of the laminated film of the present invention, it is preferable to include a nonionic surfactant, specifically one or more compounds (X) from the group consisting of alkylene glycol, acetylenediol, polyoxyethylene alkylphenyl ether, polyoxyethylene alkyl ether, glycerin fatty acid ester, sorbitan fatty acid ester, sucrose fatty acid ester, polyethylene glycol fatty acid ester, and polyoxyethylene sorbitan fatty acid ester.

[0087] The amount of compound (X) blended is preferably 0.1 parts by mass or more and 1.0 part by mass or less per 100 parts by mass of the total paint composition. More preferably, it is 0.2 parts by mass or more and 0.8 parts by mass or less, and even more preferably 0.3 parts by mass or more and 0.6 parts by mass or less.

[0088] In the laminated film of the present invention, the resin layer is determined by time-of-flight secondary ion mass spectrometry of the surface of the resin layer, and the peak intensity of the positive ion fragment exhibiting maximum intensity is M + The peak intensity of the negative ion fragment showing maximum intensity is M- When that happens, M + and M - When the peak intensity M is defined as the one with the larger absolute value among them, and the total peak intensity of the fragments derived from compound (X) is defined as Fh, it is preferable that Fh / M is between 0.05 and 0.50.

[0089] By setting the Fh / M to 0.50 or less, excess low molecular weight material remains on the surface, inhibiting the function of the release agent and preventing excessive delamination between the resin layer and the surface layer. By setting the Fh / M to 0.05 or more, uneven formation of the resin layer due to poor leveling can occur, preventing lifting and peeling during the transport process and preventing excessive delamination between the resin layer and the surface layer. A Fh / M of 0.10 to 0.50 is more preferable, and 0.20 to 0.50 is even more preferable.

[0090] The fragments detected by time-of-flight secondary ion mass spectrometry are ions produced by the decomposition of compound (X), and can take various forms depending on the structure of compound (X). Here, the fragments derived from compound (X) in this invention refer to the smallest constituent units that characterize compound (X), and specifically, 45 C2H5O + , and / or 59 C3H7O + It means a fragment consisting of [something].

[0091] The method for measuring and controlling the fragments derived from the compound (X) can be controlled by the amount of compound (X) that makes up the resin layer, the manufacturing method, and combinations thereof.

[0092] Furthermore, the laminated film of the present invention can be preferably used as a substrate for surface layer transfer, which transfers a surface layer provided on the resin layer of the laminated film. The surface layer is a general term for a film obtained by drying and solidifying a composition coated on the resin layer, and can be used as, for example, a layer of acrylic, urethane, or silicone material to impart durability and design, a polyimide protective layer having heat resistance and chemical resistance for protection from the external environment, an inorganic oxide layer and / or organic resin layer to ensure insulation between wirings in semiconductor devices, or an inorganic material layer such as aluminum oxide or silicon nitride having high hardness and high heat resistance.

[0093] Next, the method for forming the resin layer will be described. In the laminated film of the present invention, the method for providing a resin layer on at least one side of the base film can be either an in-line coating method or an off-coat method, but the in-line coating method is more preferable. The in-line coating method is a method of coating within the manufacturing process of the polyester film that will become the resin base. Specifically, it refers to a method of applying a coating composition for forming the resin layer at any stage from melt extrusion of the polyester to biaxial stretching, heat treatment, and winding. Typically, it is applied to one of the following films: a substantially amorphous unstretched (unoriented) polyester film (A film) obtained by rapid cooling after melt extrusion, a uniaxially stretched (uniaxially oriented) polyester film (B film) which is then stretched in the longitudinal direction, or a biaxially stretched (biaxially oriented) polyester film (C film) before heat treatment which is further stretched in the width direction.

[0094] When using the in-line coating method, it is preferable to apply the coating composition to either film A or film B before crystal orientation is complete, then stretch the film in a uniaxial or biaxial direction, and heat-treat it at a temperature higher than the boiling point of the solvent to complete the crystal orientation of the film and to form a resin layer. This method offers advantages in terms of manufacturing costs because it allows for the simultaneous formation of the polyester film corresponding to the resin substrate and the coating and drying of the coating composition (i.e., the formation of the resin layer), as well as making it easier to ensure adhesion between the substrate and the resin layer.

[0095] Among these methods, the method of applying the coating composition to a film (B film) that has been uniaxially stretched in the longitudinal direction, then stretching it in the width direction and heat-treating it, is superior. This is because, compared to the method of applying the coating to an unstretched film and then biaxially stretching it, there is one less stretching step, which reduces the likelihood of defects and cracks in the resin layer caused by stretching, and allows for the formation of a resin layer with excellent smoothness. Furthermore, as mentioned above, by applying the coating composition to the film before the crystal orientation is complete, adhesion between the resin layer and the polyester film can be improved.

[0096] On the other hand, the offline coating method is a method in which the above-mentioned A film is stretched uniaxially or biaxially, heat-treated to complete the crystal orientation of the polyester film, and then the coating composition is applied to the resulting film (B film or C film) in a process separate from the film manufacturing process.

[0097] In this invention, it is preferable to manufacture the laminated film by an in-line coating method. By manufacturing by an in-line coating method, it is possible to manufacture the laminated film at a lower cost than, for example, forming a resin layer on a biaxially oriented PET film by off-coating, and by applying high-temperature heat treatment of 200°C or higher, which is substantially impossible with off-coating, dense crosslinking of the resin layer can be promoted. As a result, the penetration of surface layer components into the resin layer is suppressed, so that the surface layer can be peeled off easily. In addition, the reaction between the reactive site of the long-chain alkyl group-containing resin (A) and compound (B) is promoted, preventing the migration of the long-chain alkyl group-containing resin (A) from the resin layer to the surface layer, and the deterioration of the recoatability of the surface layer can be suppressed.

[0098] In particular, it is preferable, from the viewpoint of manufacturing cost, dimensional stability after heat treatment, and thermal shrinkage characteristics, to manufacture the product by applying a coating composition to at least one side of the polyester film before the crystal orientation is completed, stretching it in at least one axial direction, and then heat-treating it to complete the crystal orientation of the polyester film.

[0099] In conventional off-coat methods, when a resin layer is applied to a polyester film (which corresponds to the resin substrate), if the resin layer contains a release agent, the low surface energy of the resin layer results in poor adhesion to the film. Therefore, laminated films obtained through such processes may experience problems such as the resin layer being scraped off when the film roll is rewound, leading to a deterioration in peel strength (equivalent to tape peel strength). On the other hand, when a resin layer is laminated using an in-line coating method, applying the coating composition to the polyester film before crystal orientation is complete allows a very small amount of the coating composition to penetrate the polyester film, thereby improving the adhesion between the resin layer and the resin substrate.

[0100] In the present invention, it is preferable to form a resin layer by applying a coating composition to at least one side of a polyester film corresponding to a resin substrate and then drying it. In the present invention, when the coating composition contains a solvent, it is preferable to use an aqueous solvent. By using an aqueous solvent, the rapid evaporation of the solvent during the drying process can be suppressed, which not only allows for the formation of a uniform and high-quality resin layer but is also environmentally friendly.

[0101] When manufacturing the laminated film of the present invention, it is preferable to dry the coating composition at a temperature range of 80 to 130°C to complete the removal of the solvent. Furthermore, when using the in-line coating method, it is preferable to perform the heat treatment at a temperature range of 180 to 240°C to complete the crystal orientation of the polyester film and to complete the formation of the resin layer by the thermal curing of the coating composition. From the above viewpoint, the heat treatment temperature is particularly preferably 120 to 240°C. If the heat treatment temperature is less than 180°C, the heat resistance of the resin substrate will decrease, and it will be difficult to obtain the crosslinking properties of the resin layer, which may lead to deterioration of the peelability of the surface layer and deterioration of the recoatability of the surface layer due to the migration of the release agent.

[0102] Next, the method for manufacturing the laminated film of the present invention will be described. The method for manufacturing the laminated film of the present invention is a method for manufacturing the laminated film of the present invention, and is characterized by comprising, in this order: a coating step of applying the resin composition for forming the resin layer, which mainly uses water as a solvent, to at least one surface of a polyester resin substrate sheet; a stretching step of stretching the polyester resin substrate sheet after the resin composition has been applied in at least one axial direction; and a heat treatment step of heating the stretched polyester resin substrate sheet to form a resin layer. In other words, the method for manufacturing the laminated film of the present invention uses an in-line coating method that performs film formation of the resin substrate and resin layer formation in a single process.

[0103] The present invention provides a method for manufacturing a laminated film, comprising a coating step of applying a resin composition for forming a resin layer, with water as the main solvent, to at least one surface of a polyester resin substrate sheet. Here, "resin composition with water as the main solvent" refers to a resin composition in which solid components are mixed with the aforementioned aqueous solvent. Furthermore, "at least one surface" refers to both sides or one side. Any known coating method can be used for applying the coating composition in the coating step, such as the bar coating method, reverse coating method, gravure coating method, die coating method, blade coating method, etc.

[0104] The present invention provides a method for manufacturing a laminated film, comprising a stretching step of stretching the polyester resin substrate sheet, after coating it with a resin composition, in at least one axial direction. Here, "stretching in at least one axial direction" means stretching in one or two axial directions. When stretching in one axial direction, a method of stretching in the longitudinal direction using a roll-type stretcher that utilizes the difference in peripheral speed of the rolls, or a method of stretching in the longitudinal or width direction using a stenter can be used. When stretching in two axial directions, after stretching in the longitudinal direction using the method described above, stretching in the width direction can be further performed using a tenter device. In the stretching step, it is preferable to stretch in two axial directions from the viewpoint of dimensional stability, mechanical strength, and flatness of the resulting laminated film.

[0105] The present invention relates to a method for manufacturing a laminated film, which includes a heat treatment step in which a stretched polyester resin substrate sheet is heated to form a resin layer. This heat treatment step completes the crystal orientation of the polyester resin substrate sheet and completes the formation of the resin layer. It is believed that this heat treatment step promotes crosslinking of the resin layer. In addition, in this heating step, a relaxation treatment of 3 to 15% may be applied in the width direction, the longitudinal direction, or both, as needed, to improve dimensional stability in a high-temperature environment.

[0106] Next, the method for manufacturing the laminated film of the present invention will be described in more detail using an example where the polyester resin base sheet is a polyethylene terephthalate (PET) film. However, the laminated film of the present invention is not limited to those obtained by this manufacturing method.

[0107] First, PET pellets are thoroughly vacuum-dried, then fed into an extruder and melt-extruded into a sheet at 270-290°C. This is then cooled and solidified in a casting drum with a surface temperature of 20-40°C to produce an unstretched (unoriented) PET film (Film A, corresponding to a polyester resin substrate sheet). This Film A is stretched 2.5-5.0 times in the longitudinal direction on a roll heated to 80-120°C to obtain a uniaxially oriented PET film (Film B). A coating composition prepared to a predetermined concentration is applied to one side of Film B. At this time, surface treatment such as corona discharge treatment may be performed on the coated surface of the PET film before application. Surface treatment such as corona discharge treatment improves the wettability of the coating composition to the PET film, prevents the coating composition from repelling, and achieves a uniform coating thickness. After application, the ends of the PET film are gripped with clips and guided to a heat treatment zone (preheating zone) at 80-130°C to dry the solvent of the coating composition. After drying, it is stretched 1.1-5.0 times in the width direction. The material is then guided to a heating zone (heat treatment zone) at 150-250°C (preferably 160-240°C, more preferably 180-240°C) and subjected to heat treatment for 1-30 seconds to complete crystal orientation and resin layer formation. This heating step (heat treatment step) is thought to promote crosslinking of the resin layer. In addition, during this heating step (heat treatment step), a relaxation treatment of 3-15% in the width direction or longitudinal direction may be applied as needed. A laminated film can be obtained in this way, and the obtained laminated film can be wound into a roll to form a film roll. [Examples]

[0108] The laminated film of the present invention will be described in more detail below using examples, but the laminated film of the present invention is not limited thereto.

[0109] [Methods for measuring characteristics and evaluating effects] The method for measuring the properties and evaluating the effects in this invention is as follows.

[0110] (1) Tape peeling force Acrylic adhesive tape (Nitto Denko Corporation, No. 31B tape, 19 mm wide, total thickness 0.053 mm) was laminated onto the resin layer of a laminated film, and a 2 kgf roller was passed over it once to create a tape-laminated laminated film. After that, the tape-laminated laminated film was left to stand for 24 hours in an environment of 25°C and 65% RH, and the peel force was measured using a Shimadzu Corporation universal testing machine "Autograph" (registered trademark) AG-1S at a peel angle of 180° and a tensile speed of 300 mm / min. From the peel force-test time (sec) graph obtained from the measurement, the average value of the peel force at 5 to 10 sec was calculated and converted to a value for a measurement width of 50 mm. This measurement was performed 5 times, and the average of the 3 measurements excluding the maximum and minimum values ​​was taken as the peel force (N / 50 mm) of the laminated film.

[0111] (2)Residual adhesion rate The Nitto Denko 31B adhesive tape (tape width 19 mm, total thickness 0.053 mm) that was peeled off from the laminated film surface by the tape peel strength test in (1) was applied to a SUS plate that had been thoroughly cleaned with ethanol, and the environment was conditioned at 25°C and 65% RH. Subsequently, the peel strength F1 between the tape and the SUS plate was measured in the same manner as in (1).

[0112] On the other hand, unused 31B adhesive tape (tape width 19 mm) was applied to a SUS plate that had been thoroughly cleaned with ethanol, and the atmosphere was conditioned at 25°C and 65% RH. Subsequently, the peel strength F2 between the 31B adhesive tape and the SUS plate was measured in the same manner as in (1). From the obtained F1 and F2, the residual adhesion rate was calculated using the following formula. Residual adhesion rate (%)=(F1 / F2)×100 (3) Receding contact angle with respect to water The receding contact angle of the resin layer with respect to water was measured using the expansion-contraction method with a Drop Master DM-501 contact angle meter manufactured by Kyowa Interface Science, according to the device's expansion-contraction method measurement manual. First, the laminated film was left to stand for 24 hours in an atmosphere at room temperature (25°C) and relative humidity (65%). Then, under the same atmosphere, a droplet of pure water with a volume of 55 μL was created on the surface side of the resin layer of the laminated film. Next, with the tip of a syringe needle still inserted into the droplet, it was continuously aspirated at a liquid discharge rate of 5.6 μL / s. The shape of the droplet during the shrinking process was continuously photographed from the side of the droplet every 100 milliseconds starting 5000 milliseconds after the start of aspiration, and the contact angle was calculated from each captured image. The contact angle initially changes as the droplet contracts, and then becomes constant. The contact angle at this point was defined as the receding contact angle. To determine that the contact angle had become constant, the contact angles calculated from images taken continuously at 100-millisecond intervals were arranged sequentially over time. Five consecutive points were selected in this order, and the average value at which the standard deviation of these five consecutive points first fell below 1° was defined as the receding contact angle θr for that measurement. This measurement was performed five times for each sample, and the average of the three measurements excluding the maximum and minimum values ​​was defined as the receding contact angle of the water in that sample.

[0113] (4) Composition of the resin layer surface (peak intensity of each ion) The surface composition of the resin layer of the laminated film was analyzed using time-of-flight secondary ion mass spectrometry (TOF-SIMS). The measurement conditions were as follows. In the resulting chart, the peak intensity M of the fragment showing the highest intensity and the peaks of each fragment used for analysis were determined. <Measurement conditions> Measurement device: TOF.SIMS 5 (manufactured by ION-TOF) Analysis software: SurfaceLab Primary ion: Bi3 ++ Primary ion acceleration voltage: 25kV Secondary ion polarity: positive ion Mass range: m / z 0~1,000 Measurement range: 400 μm × 400 μm Number of scans: 25 scans Pulse width: 10.2ns Bunching: Yes Neutralization of static charge: Yes Rear acceleration: 9.5kV Measurement vacuum degree: 1×10 -7 Below Pa.

[0114] (4-1) Peak intensities of positive ion fragments derived from polydimethylsiloxane: Si and Si / M + The positive ion peak originates from polydimethylsiloxane. 43 Si Black 3 + The peak intensity Si of the same positive ion is the fragment peak intensity M that accounts for the maximum intensity. + Normalization was performed by dividing by Si / M. The measurement was repeated three times, and the average value was taken. + That's what I decided.

[0115] (4-2) Negative ions derived from the element fluorine ( 17 F - ) Peak intensity Ff and Ff / M - The negative ion peak originates from the element fluorine. 17 F - The peak intensity Ff of ) is the fragment peak intensity M that accounts for the maximum intensity in the same negative ion. - The value was normalized by dividing by Ff / M. The measurement was repeated three times, and the average value was taken as Ff / M. - That's what I decided.

[0116] (4-3) Total peak intensities Fh and Fh / M of fragments derived from compound (X) Similarly, from the resulting chart (horizontal axis: mass number / vertical axis: signal intensity), fragments of compound (X) contained in the resin layer and resin substrate can be identified, i.e. 45 C2H5O + , 59 C3H7O +The peak intensity of the ion and the peak intensity of the resin substrate fragment were read. Next, with the aim of uniformly calculating positive and negative ions and eliminating inter-measurement differences between samples, the peak intensity M of the positive ion fragment showing the highest intensity was read. + and the peak intensity M of the negative ion fragment showing maximum intensity - Of these, the one with the larger absolute value was taken as the maximum peak intensity M, and normalized to a dimensionless quantity by dividing Fh by M. The measurement was repeated three times, and the average value was taken as the sum of the peak intensities of the fragments derived from compound (X), which was taken as Fh / M.

[0117] (5) The arithmetic mean roughness Sa of the surface opposite to the surface having the resin layer A 5cm x 5cm square sample was obtained from the laminated film and measured and calculated according to ISO 25178-2:2012 and ISO 25178-3:2012. The measuring instrument used was a scanning white light interference microscope "VS1540" (manufactured by Hitachi High-Tech Science Corporation). Details of the measurement conditions and instrument configuration will be described later.

[0118] Sa was calculated using the data obtained by interpolating (completely interpolating) the captured image using the included analysis software, correcting the surface using a quartic polynomial approximation, and then processing it with a median filter (3x3 pixels). The S-filter Nesting Index was set to 0.455. Measurement points were set at the intersection of the diagonals (starting point) and at 1 cm away from each of the four corners, for a total of 5 points. Measurements and Sa calculations were performed at each measurement position, and the average of the obtained values ​​was adopted as the arithmetic mean roughness Sa. <Measurement conditions and equipment configuration> Objective lens: 10x Telescope tube: 1x Zoom lens: 1x Wavelength filter: 530nm white Measurement mode: Wave Measurement software: VS-Measure 10.0.4.0 Analysis software: VS-Viewer 10.0.3.0 Measurement area: 561.1μm×561.5μm Pixel count: 1,024 x 1,024.

[0119] (6) Adhesion of the surface layer An epoxy resin varnish mixed to the composition described below was applied to the resin layer of the laminated film of the present invention using an applicator to a final thickness of 40 μm. The varnish was then dried in a hot air oven at 100°C for 5 minutes to form an epoxy resin laminated sheet. A 10 cm square sheet of the epoxy resin laminated sheet was left in an atmosphere of 60°C and 90% RH for 100 hours, then removed and placed in an atmosphere of 23°C and 50% RH. After 1 hour, the state of the epoxy resin laminated sheet was visually observed to evaluate its ability to suppress lifting. <Criteria for evaluating buoyancy suppression> S: No lifting, peeling, or bubble formation whatsoever. A: There are several instances of lifting, peeling, or air bubbles at the edges. B: Lifting, delamination, or bubble formation is present in the center. C: Lifting, peeling, or air bubbles are present throughout the entire surface. The following evaluations were conducted: S and A were considered good, and B was considered to be at a level that is acceptable for practical use.

[0120] In the above evaluation, if the longitudinal and width directions of the film are unknown, the direction with the greatest refractive index in the film will be considered the width direction, and the direction perpendicular to the width direction will be considered the longitudinal direction. <How to make epoxy resin varnish> 15.78 g of bisphenol A type liquid epoxy resin (RE-410S, manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent 178), 0.17 g of curing accelerator (2MAOK-PW, manufactured by Shikoku Kasei Co., Ltd.), and 19.43 g of N,N-dimethylformamide were stirred at room temperature (23°C) for 2 hours until a homogeneous solution was obtained.

[0121] Next, 17.23 g of a biphenyl-type phenol curing agent (MEH7851-4H, manufactured by Meiwa Kasei Co., Ltd., OH equivalent 243, softening point 130°C) was added, and the mixture was stirred at room temperature (23°C) for 1 hour to prepare an epoxy resin varnish.

[0122] (7) Peeling force of the surface layer The peel strength of the surface layer was measured as follows: The epoxy resin laminate sheet described in section (6) "Adhesion of the surface layer" was further heated in a hot air oven at 150°C for 30 minutes to form a post-heat epoxy resin laminate sheet. An acrylic adhesive tape (Nitto Denko Corporation, Nitto 31B tape, 50 mm wide, total thickness 0.053 mm) was laminated onto the epoxy resin of the post-heat epoxy resin laminate sheet as a support, and the peel strength (N / 50 mm) was measured using a Shimadzu Corporation universal testing machine "Autograph AG-1S" at a peel angle of 180° and a tensile speed of 300 mm / min. From the graph of peel strength (N / 50 mm) - test time (sec) obtained from the measurement, the average value of the peel strength at 5 to 10 seconds was calculated. This measurement was performed 5 times, and the average of the 3 measurements excluding the maximum and minimum values ​​was taken as the peel strength (N / 50 mm) of the laminate film, and it was evaluated according to the following criteria. Items rated S and A were considered good, while items rated B were considered to be at a level where there were no practical problems. S: Peeling force 8.0N / 50mm or less A: Peeling force 8.0N / 50mm or more, less than 12.0N / 50mm B: Peeling force 12.0 N / 50 mm or more, less than 15.0 N / 50 mm C: Peeling force 15.0 N / 50 mm or more.

[0123] (8) Recoating properties of the surface layer In the evaluation of "(6) Adhesion of the surface layer," an acrylic UV-curable resin (DIC's "Unidick" V6841) was uniformly applied to the peeled surface layer using a bar coater so that the cured film thicknesses were 3 μm, 1 μm, and 0.5 μm, and the cumulative irradiation intensity was 500 mJ / cm². 2 After UV irradiation, a visual evaluation was performed. Generally, the smaller the coating thickness, the more likely repellency is to occur. S: No repellency was observed at any coating thickness. A: No repellency is observed at coating thicknesses of 3 μm and 1 μm, but repellency is observed at 0.5 μm. B: No repellency is observed at a coating thickness of 3 μm, but repellency is observed at 1 μm and 0.5 μm. C: Repellency is observed at all coating thicknesses. Grades S and A or higher are considered to have good surface layer recoating properties, while grade B is considered to be at a level that does not pose practical problems.

[0124] [Raw materials for resin substrates] • Polyester raw material 1 (homopolyester) 86.5 parts by mass of terephthalic acid and 37.1 parts by mass of ethylene glycol were mixed, and an esterification reaction was carried out at 255°C while distilling off water. After the esterification reaction was completed, 0.02 parts by mass of trimethyl phosphate, 0.06 parts by mass of magnesium acetate, 0.01 parts by mass of lithium acetate, and 0.0085 parts by mass of antimony trioxide were added, and subsequently, under reduced pressure, the mixture was heated to 290°C and the temperature was increased to carry out a polycondensation reaction to obtain polyester raw material 1 with an intrinsic viscosity of 0.63 dl / g.

[0125] • Polyester raw material 2 (organic particle master pellets) Using a vented twin-screw kneader, an aqueous slurry of divinylbenzene / styrene copolymer crosslinked particles with a volume-average particle size of 0.3 μm and a volume-shaft shape coefficient of f = 0.51 was incorporated into the above substantially particle-free polyester raw material 1 to obtain a master pellet (polyester raw material 2) containing 2% by mass of divinylbenzene / styrene copolymer crosslinked particles with a volume-average particle size of 0.3 μm relative to the polyester.

[0126] • Polyester raw material 3 (recycled material) The aforementioned resin substrate 1 was recovered and re-pelletized to obtain polyester raw material 3.

[0127] • Polyester raw material 4 (inorganic particle master pellets) Calcium carbonate with an average particle size of 1.0 μm was prepared by laser diffraction and used to make a 10% by mass ethylene glycol slurry. This slurry was dispersed using a jet agitator for one hour and then filtered with high precision using a filter with a collection efficiency of 95% for particles of 5 μm or larger. A transesterification reaction was carried out by adding 100 parts by mass of dimethyl terephthalate and 64 parts by mass of ethylene glycol, along with 0.04 parts by mass of manganese acetate and 0.03 parts by mass of antimony trioxide as catalysts. Subsequently, 0.04 parts by mass of trimethyl phosphate as a phosphorus compound was added to the reaction product, and then 1.0 part by mass of the previously prepared slurry was added to carry out a polycondensation reaction to obtain a calcium carbonate-containing master pellet (polyester raw material 4) with an intrinsic viscosity of 0.63 dl / g and containing 1% by mass of calcium carbonate with an average particle size of 1.0 μm.

[0128] <Resin substrate> • Resin base material 1: Polyester film 95 parts by mass of polyester raw material 1 and 5 parts by mass of polyester raw material 2 were dry-blended and thoroughly vacuum-dried. The mixture was then supplied to an extruder and melted at 280°C. It was extruded into a sheet through a T-shaped die and wrapped around a mirror-finish casting drum with a surface temperature of 25°C using an electrostatic casting method to cool and solidify, thereby obtaining an unstretched film (film A). This unstretched film was heated to 90°C and stretched 3.1 times in the longitudinal direction to obtain a uniaxially oriented film (film B) of resin substrate 1.

[0129] • Resin base material 2: Polyester film A uniaxially oriented film of resin substrate 2 was obtained using the same method as for resin substrate 1, except that 100 parts by mass of polyester raw material 1 was used.

[0130] • Resin base material 3: Polyester film A uniaxially oriented film of the resin substrate 3 was obtained using the same method as for the resin substrate 1, except that the polyester raw material 3 was 100 parts by mass.

[0131] • Resin base material 4: Polyester film A uniaxially oriented film of resin substrate 4 was obtained in the same manner as for resin substrate 1, except that a raw material prepared by dry-blending 95 parts by mass of polyester raw material 1 and 5 parts by mass of polyester raw material 4 was used.

[0132] <Paint composition for resin layer formation> • Release agent 1: Long-chain alkyl resin 200 parts by mass of xylene and 600 parts by mass of octadecyl isocyanate were added to a four-necked flask and heated with stirring. From the point when the xylene began to reflux, 100 parts by mass of polyvinyl alcohol with an average degree of polymerization of 500 and a degree of saponification of 88 mol% was added in small amounts at 10-minute intervals over approximately 2 hours. After the addition of polyvinyl alcohol was completed, reflux was continued for another 2 hours to terminate the reaction. The reaction mixture was then cooled to approximately 80°C and added to methanol, and the resulting white precipitate was filtered off. 140 parts by mass of xylene was added to the obtained white precipitate, heated to completely dissolve it, and then methanol was added again to precipitate it. This process was repeated several times. The obtained precipitate was then washed with methanol and dried and ground to obtain a long-chain alkyl group-containing resin (having an alkyl group with 18 carbon atoms in the side chain) having a hydroxyl group as a reactive functional group. This was diluted with deionized water to a concentration of 20% by mass to obtain release agent 1.

[0133] • Release agent 2: Long-chain alkyl resin A release agent 2 was obtained using the same method as for release agent 1, except that dodecyl isocyanate was used instead of octadecyl isocyanate, and the resin was a long-chain alkyl-containing resin (having an alkyl group with 12 carbon atoms in the side chain).

[0134] • Release agent 3: Olefin resin 60.0 g of acid-modified polyolefin resin (Arkema Bondine LX-4110, ethylene / ethyl acrylate / maleic anhydride = 91 / 7 / 2 (mass%), MFR: 5 g / 10 min, melting point: 107°C, Vicat softening point: 83°C), 90.0 g of isopropanol (IPA), 3.0 g of N,N-dimethylethanolamine (DMEA, 1.0 equivalent to the carboxyl groups of the maleic anhydride units in the resin), and 147.0 g of distilled water were placed in a glass container. The impeller rotation speed was set to 300 rpm, and the system temperature was maintained at 140-145°C for 60 minutes while stirring. After that, the container was placed in a water bath and cooled to room temperature (approximately 25°C) while stirring at a rotation speed of 300 rpm. Subsequently, to remove the organic solvent from the aqueous medium, a rotary evaporator was used to distill off a portion of the aqueous medium at a bath temperature of 80°C while adding water. Subsequently, the mixture was cooled to room temperature (25°C) by air cooling, and then pressure filtered (air pressure 0.2 MPa) was performed using a 300-mesh stainless steel filter (wire diameter 0.035 mm, plain weave). This yielded a milky white, uniform acid-modified polyolefin resin (solid content concentration: 20% by mass, IPA: 0% by mass, DMEA: 0.9% by mass) as the mold release agent 3.

[0135] • Release agent 4: Silicone resin Silicone emulsion 400E (manufactured by Wacker Silicones, solids content 50% by mass).

[0136] <Compound> • Compound 1: Acrylic resin In a stainless steel reaction vessel, methyl methacrylate (α), ethyl acrylate (β), 2-hydroxyethyl acrylate (γ) having a hydroxyl group as a reactive functional group, and acrylonitrile (δ) were charged in a mass ratio of (α) / (β) / (γ) / (δ) = 60 / 32 / 6 / 2 to prepare a mixture. In a reaction vessel equipped with a stirrer, reflux condenser, thermometer, and dropping funnel, 50 parts by mass of the mixture prepared above, 200 parts by mass of isopropyl alcohol, and 0.5 parts by mass of 2,2'-azobis(isobutyronitrile) (AIBN) were charged, and the temperature was raised until the mixture refluxed. After holding the mixture at the refluxed state for 20 minutes, the remaining mixture, along with a mixture of 60 parts by mass of isopropyl alcohol and 1.8 parts by mass of AIBN, was added dropwise over 120 minutes. Twenty minutes after the end of the dropwise addition, a mixture of 40 parts by mass of isopropyl alcohol and 1.5 parts by mass of AIBN was added dropwise over 120 minutes, and the reflux was maintained for another 120 minutes. After the reaction mixture was cooled to below 50°C, it was transferred to a reaction vessel equipped with a stirrer and a vacuum device, and 50 parts by mass of 25% ammonia water and 900 parts by mass of deionized water were charged in. The isopropyl alcohol and unreacted monomers were recovered under reduced pressure at 60°C to obtain acrylic resin aqueous dispersion 1. Furthermore, 240.5 parts by mass of deionized water and 100 parts by mass of the acrylic resin aqueous dispersion 1 prepared above were charged into a reaction vessel equipped with a thermometer, stirring rod, reflux condenser, and dropping funnel, and the temperature was raised to 80°C while purging the reaction vessel with nitrogen.

[0137] Meanwhile, in a stirring vessel separate from the reaction vessel, 42.7 parts by mass of deionized water, 9 parts by mass of "Adekaria Soap" (registered trademark) ER-30 (nonionic reactive surfactant, active ingredient: 65% by mass, manufactured by ADEKA Corporation, reactive emulsifier), and 0.5 parts by mass of N-methylolacrylamide (NMAM) were added and stirred. Then, a solution of 61.3 parts by mass of methyl methacrylate (MMA) and 37.0 parts by mass of n-butyl acrylate (BA) was added and stirred to prepare a preemulsion.

[0138] Next, while maintaining the internal temperature of the reaction vessel at 80°C, 1.0 part by mass (active ingredient: 0.7 parts by mass) of perbutyl PV (chemical name: t-butyl peroxypivalate, organic peroxide, active ingredient: 70% by mass, manufactured by NOF Corporation) was added to initiate the polymerization reaction. Five minutes after addition, the pre-emulsion prepared above was uniformly added sequentially over three hours to carry out polymerization. The resulting polymer was aged at 80°C for two hours, then cooled to room temperature. The pH was adjusted with an appropriate amount of aqueous ammonia solution to obtain an acrylic resin aqueous dispersion (compound 1) with a pH of 8.5. The acid value of the obtained resin was 65 mgKOH / g.

[0139] • Compound 2: Polyester resin "Pluscoat" (registered trademark) Z760, manufactured by Go-O Chemical Industry Co., Ltd. (-COOH group contained, solid content concentration 25% by mass, acid value 50 mgKOH / g).

[0140] • Compound 3: Polyester resin "Pluscoat" (registered trademark) Z561, manufactured by Go-O Chemical Industry Co., Ltd. (contains -SO3Na group, solid content concentration 25% by mass, acid value 2 mgKOH / g).

[0141] Compound 4: Melamine compound (methylolated melamine) Manufactured by Sanwa Chemical Co., Ltd., "Nikarac" (registered trademark) MW-035 (solid content concentration 70% by mass, solvent: water).

[0142] • Compound 5: Oxazoline compound Nippon Shokubai Co., Ltd., "Epocross" (registered trademark) WS-500 (solid content concentration 40% by mass, solvent: water) • Compound 6: Crosslinking agent for silicone resins CROSSLINKER V72 (Solid content concentration 50% by mass, solvent: water), manufactured by Asahi Kasei Wacker Silicone Co., Ltd.

[0143] <Crosslinking catalyst> • Catalyst 1: Dodecylbenzenesulfonic acid Manufactured by Kusumoto Kasei Co., Ltd., “NACURE” (registered trademark) 5528 (Manufacturer: KING INDUSTRIES).

[0144] <Surfactants> • Surfactant 1: Acetylenediol-based surfactant "Orphine" (registered trademark) EXP.4200, manufactured by Nisshin Chemical Industry Co., Ltd. • Surfactant 2: Polyoxyethylene oleyl ether Manufactured by Kao Corporation, Product name: "Emulgen" (registered trademark) 404 • Surfactant 3: Fluorine-based surfactant "Pluscoat" RY-2, manufactured by Go-O Chemical Industry Co., Ltd. (Example 1) As shown in Table 1, release agent 1 / compound 1 was mixed in a solid content mass ratio of 15 / 85. Next, water was added to adjust the solid content concentration according to the target coating film thickness. Furthermore, an acetylenediol-based surfactant ("Orphine" (registered trademark) EXP.4200, manufactured by Nisshin Chemical Industry Co., Ltd.) was added in an amount of 0.1 parts by mass per 100 parts by mass of the mixed coating composition to obtain a coating composition for forming a resin layer.

[0145] Next, the uniaxially oriented film of the resin substrate 1, while it was moving through the film manufacturing process, was subjected to corona discharge treatment in air. Then, the coating composition for forming the resin layer was applied to a thickness of approximately 6 μm using a wire bar coat. Subsequently, both ends of the uniaxially oriented film coated with the coating composition were gripped with clips in the width direction and guided to a tenter, where the solvent of the coating composition was dried in a preheating zone with an ambient temperature of 90-100°C. Subsequently, it was continuously stretched 3.8 times in the width direction in a stretching zone at 100°C, followed by heat treatment for 20 seconds in a heat treatment zone at 235°C to form a resin layer, and then a 5% relaxation treatment in the width direction was performed at the same temperature to complete the crystal orientation of the polyester film. In the resulting laminated film, the thickness of the PET film was 50 μm, and the thickness of the resin layer was 50 nm.

[0146] Subsequently, the film was cut parallel to its longitudinal direction using a slitter, thereby cutting and removing the uncoated portions at both ends in the width direction that the clips had been holding, and the laminated polyester film was wound into a roll. The properties of the obtained laminated polyester film are shown in Tables 2 and 3.

[0147] (Examples 2, 6-8, Comparative Examples 1, 4) Various laminated polyester films were obtained in the same manner as in Example 1, except that the composition of the resin substrate and the coating composition for forming the resin layer was changed as shown in Table 1. The properties of the obtained laminated films are shown in Tables 2 and 3.

[0148] (Example 3) After subjecting the uniaxially oriented film of the resin substrate 2, which was running through the film manufacturing process, to corona discharge treatment in air, the coating composition 3 described in Table 1 was applied to a coating thickness of approximately 6 μm using a wire bar coat. Furthermore, as coating composition 3-2 to be applied to the side opposite to the side with the resin layer, acrylic resin (compound 1) and melamine resin (compound 4) were mixed in a solid content mass ratio of 15 / 85, and 3 parts by mass of silica particles with a particle size of 140 nm (Spherica® 140 manufactured by Catalytic Chemicals Co., Ltd.) were added to these resins, and surfactant 1 was added in an amount of 0.1 parts by mass per 100 parts by mass of the total coating composition to obtain coating composition 3-2. The obtained coating composition 3-2 was applied to the side opposite to the side with the resin layer using a gravure coat to a coating thickness of approximately 10 μm. Various laminated polyester films were obtained in the same manner as in Example 1. The characteristics of the obtained laminated films are shown in Tables 2 and 3.

[0149] (Examples 4 and 5, Comparative Example 2) Various laminated polyester films were obtained in the same manner as in Example 3, except that the composition of the resin substrate and the coating composition for forming the resin layer was changed as shown in Table 1. The properties of the obtained laminated films are shown in Tables 2 and 3.

[0150] (Example 9) A laminated film was obtained using the coating composition of Example 3 by the following method. A polyethylene terephthalate (PET) film "Lumirror" (registered trademark) T60 (substrate thickness 50 μm) manufactured by Toray Industries, Inc. was used as the substrate. The coating composition with the composition shown in Table 1 was applied to the substrate using an offline coating method with a wire bar. Next, to prevent deformation due to heat, a SUS plate film of the same type as the film was placed on top, and after gripping all four sides without gaps with double clips, drying and curing were carried out in a hot air oven at 150°C for 2 minutes to obtain a laminated film. The properties of the obtained laminated film are shown in Tables 2 and 3.

[0151] (Comparative Example 3) Release agent 4 / compound 3 / compound 6 were mixed in the proportions shown in Table 1. Next, a silane coupling agent (manufactured by Shin-Etsu Silicone Co., Ltd., trade name: KBM-403) and surfactant 2 (0.15 parts by mass per 100 parts by mass of the mixed coating composition) were added to 100 parts by mass of the total release agent and compounds so that the solid content was 5 parts by mass, thereby obtaining a silicone emulsion coating composition. The solid content concentration of the coating was 6.0% by mass. The subsequent steps were carried out in the same manner as in Example 1, except that a uniaxially oriented film of resin substrate 2 was used, to obtain a laminated film. The properties of the obtained laminated film are shown in Tables 2 and 3.

[0152] [Table 1]

[0153] [Table 2]

[0154] [Table 3] [Industrial applicability]

[0155] The laminated film of the present invention can be suitably used as a process film in the manufacture of electronic components, battery components, printed circuit boards, and automotive components. More specifically, it can be suitably used as a process film for manufacturing layers of acrylic, urethane, or silicone materials to provide durability and aesthetic appeal; polyimide protective layers with heat resistance and chemical resistance for protection from the external environment; inorganic oxide layers and / or organic resin layers to ensure insulation between wiring in semiconductor devices; and inorganic material layers such as aluminum oxide and silicon nitride that have high hardness and high heat resistance. [Explanation of symbols]

[0156] 1. Polyester resin base material 2 resin layers 3. Laminated film 4. Hydrophobic parts 5 Hydrophilic site 6. Surfactants 7 Surface layer

Claims

1. A laminated film having a resin layer containing a long-chain alkyl group resin (A) on at least one side of a polyester resin base layer, wherein the tape peel strength is 2.0 N / 50 mm or more and 12.0 N / 50 mm or less, and the residual adhesion rate is 50% or more and 95% or less.

2. The laminated film according to claim 1, wherein the receding contact angle with water on the surface of the resin layer is 50° or more and 85° or less.

3. The peak intensity of the positive ion fragment exhibiting maximum intensity, detected by time-of-flight secondary ion mass spectrometry on the surface of the resin layer, is M ＋ When the peak intensity of the positive ion fragment derived from polydimethylsiloxane is taken as Si, the Si / M ＋ The laminated film according to claim 1 or 2, wherein is less than 0.

01.

4. The peak intensity of the negative ion fragment exhibiting maximum intensity, detected by time-of-flight secondary ion mass spectrometry on the surface of the resin layer, is M － , negative ions (F) derived from the element fluorine - When the peak intensity of ) is Ff, Ff / M － The laminated film according to claim 1 or 2, wherein is less than 0.

01.

5. The laminated film according to claim 1 or 2, wherein the resin layer comprises one or more compounds (X) from the group consisting of alkylene glycol, acetylenediol, polyoxyethylene alkylphenyl ether, polyoxyethylene alkyl ether, glycerin fatty acid ester, sorbitan fatty acid ester, sucrose fatty acid ester, polyethylene glycol fatty acid ester, and polyoxyethylene sorbitan fatty acid ester.

6. The peak intensity of the fragment of the positive ion showing the maximum intensity, detected by time-of-flight secondary ion mass spectrometry on the surface of the resin layer, is M ＋ The peak intensity of the fragment of the negative ion showing the maximum intensity is M － When, ＋ and M － Among them, the one with the larger absolute value is defined as the maximum peak intensity M, and when the total peak intensity of the fragments derived from the compound (X) is Fh, the laminated film according to claim 5, wherein Fh / M is 0.05 or more and 0.50 or less.

7. The laminated film according to claim 1 or 2, wherein the resin layer contains at least one compound (B) selected from acrylic resin, polyester resin, urethane resin, oxazoline compound, carbodiimide compound, and melamine resin.

8. The laminated film according to claim 7, wherein the mass ratio of the long-chain alkyl group-containing resin (A) to the compound (B) in the resin layer, i.e., the long-chain alkyl group-containing resin (A) / compound (B), is 5 / 95 or more and 30 / 70 or less.

9. The laminated film according to claim 1 or 2, wherein the arithmetic mean height Sa of the laminated film surface opposite to the surface having the resin layer is 1.0 nm or more and 30.0 nm or less.

10. The laminated film according to claim 1 or 2, wherein the polyester resin substrate layer includes at least one of biomass raw materials and recycled raw materials.

11. A laminate for surface layer transfer, comprising a surface layer further laminated on the surface of the resin layer of the laminated film according to claim 1 or 2.

12. A method for producing a laminated film according to claim 1 or 2, comprising the steps of applying a coating composition containing the long-chain alkyl group-containing resin (A) to at least one side of a polyester film before crystal orientation is completed, stretching it in at least one axial direction, and then heat-treating it to complete the crystal orientation of the polyester film.

Images