Resin film, resin film with separator, laminate, and method for producing same

Abstract

Provided is a resin film which has a first surface and a second surface, wherein at least the first surface has a relief structure, and the relief structure of the first surface has a load area ratio Smr(C) of 7% to 37% inclusive at C that satisfies the requirement of formula (1).　(1): C = Sdc(0.2%) – Spk - (Sk / 5) - 0.5 (µm) (In formula (1), Sdc(0.2%) is the level height at a load area ratio of 0.2%, Spk is the profile peak height, and Sk is the core height. Smr(C) is the load area ratio (%) at the time when the level height is C.)

Description

Resin film, resin film with separator, laminate, and method for producing the same

[0001] The present invention relates to a resin film, a resin film with a separator, and a laminate used for an interlayer film of laminated glass or the like.

[0002] Conventionally, a resin film made of a polyvinyl acetal resin or the like is disposed between two glass members and widely used as an interlayer film for laminated glass to bond them. In recent years, an interlayer film for laminated glass has been studied to include a functional layer such as a light control element or electronic components (see, for example, Patent Document 1). When including a light control element or the like, on the resin film, a light control element, a spacer resin film for filling a step, etc. are arranged and laminated side by side, aligned, and then, if necessary, another resin film is further overlapped and then directly bonded. In addition, a functional layer such as a light control element may be disposed between two resin films so that the resin films do not contact each other, and may be pressure-bonded by thermocompression bonding or the like and included in the interlayer film.

[0003] Generally, the surface of an interlayer film for laminated glass often has irregularities formed by embossing or the like. By having irregularities on the surface, the interlayer film becomes slippery with respect to the glass plate, blocking during storage is prevented, and workability during lamination can be improved.

[0004] Also, in various members other than the interlayer film for laminated glass, it is widely known that irregularities are formed to exhibit various functions. For example, as shown in Patent Document 2, it is known to form minute irregularities on at least a part of the surface of a glass member. In Patent Document 2, in the surface of a glass member having minute irregularities, in the load curve of the surface within a square region having a side of 5 μm, the range of the load area ratio from 10% to 99% is obtained by performing simple regression analysis by the least squares method, and it is shown that the coefficient of determination R2 of the regression line is 0.600 or more and 0.960 or less. In Patent Document 2, it is shown that with the above configuration, the touch feeling such as the writing feeling by an input pen or the touch feeling by a fingertip can be excellent.

[0005] International Publication No. 2019 / 066042, Japanese Patent Publication No. 2023-038097

[0006] Incidentally, interlayers containing functional layers are often laminated by roll-to-roll lamination, followed by pressing them onto a glass plate to create laminated glass. However, in recent years, due to the integration of electronic components and other factors, the structure of interlayers has become more complex, and sometimes the functional layer is laminated onto an interlayer (resin film) that has been pre-cut into a single sheet of the desired size. In this case, if the functional layer is not positioned in the specified location on the resin film, it may lead to a decrease in the performance of the functional layer. Also, if there are large gaps between other components arranged on the resin film, these gaps may cause air bubbles to form when laminated glass is created. Therefore, when laminating a functional layer on a resin film, precise alignment with other components and the resin film is sometimes required.

[0007] Furthermore, since the functional layer may shift position during transport or the resin film may shrink at room temperature after lamination, it is desirable to minimize unintended shifting after lamination on the resin film. On the other hand, the functional layer may not be able to be positioned precisely when laminating on the resin film, and it may be necessary to make it easy to readjust the position and align it even after lamination on the resin film.

[0008] To prevent misalignment, one could consider bonding the functional layer and the resin film with a solvent or adhesive, or heat-sealing them using a laser or hot press. However, bonding with solvents or adhesives generally results in high tackiness, making positional adjustment difficult after bonding, and there is also a risk that the solvent or adhesive may affect the quality of the final product. Furthermore, heat sealing with a laser or hot press can cause the resin film to shrink due to the heat during sealing, creating gaps, and requires high temperatures, making it undesirable from a safety standpoint.

[0009] Furthermore, conventional embossed interlayers have good slipperiness, making it easy to adjust the position of the component laminated on the interlayer, but it is difficult to sufficiently prevent misalignment. Moreover, the uneven shape disclosed in Patent Document 2 does not demonstrate that it is possible to make the component laminated on the resin film less prone to misalignment while also providing good position adjustment performance.

[0010] Therefore, the object of the present invention is to provide a resin film that has good positional adjustment performance when laminating various components such as functional layers onto the resin film, and that prevents unintended positional displacement of the various components after lamination.

[0011] The present invention provides the following [1] to

[23] . [1] A resin film having a first surface and a second surface, wherein at least the first surface has an uneven structure, and the uneven structure of the first surface satisfies the requirements of the following formula (1), and the load area ratio Smr(C) at C is 7% or more and 37% or less. C = Sdc(0.2%) - Spk - (Sk / 5) - 0.5 [μm] (1) (Note that in formula (1), Sdc(0.2%) is the level height at a load area ratio of 0.2%, Spk is the height of the protruding peak, and Sk is the height of the core. Smr(C) is the load area ratio (%) when the level height is C) [2] The resin film according to [1] above, wherein the uneven structure has a random shape. [3] The resin film according to [1] or [2] above, wherein the Spk of the uneven structure of the first surface is 0.4 μm or more and 7 μm or less. [4] The resin film according to any one of [1] to [3], wherein the Sk of the uneven structure of the first surface is 1.0 μm or more and 10 μm or less. [5] The resin film according to any one of [1] to [4], comprising the first surface which is temporarily bonded to an adherend by ultrasonic bonding. [6] The resin film according to any one of [1] to [5], wherein the load area ratio Smr(C) is 7% or more and 12% or less, comprising the first surface which is temporarily bonded to an adherend by ultrasonic bonding. [7] The resin film according to any one of [1] to [6], wherein the thickness of the resin film is 50 μm or more and 1 mm or less. [8] The resin film according to any one of [1] to [7], wherein the resin film contains a thermoplastic resin. [9] The resin film according to [8], wherein the thermoplastic resin is at least one selected from the group consisting of polyvinyl acetal resin, ethylene-vinyl acetate copolymer resin, polyurethane resin, and ionomer resin.

[10] A resin film with a separator, comprising a resin film according to any one of [1] to [9] above, and a release substrate provided on at least one of the first and second surfaces of the resin film.

[11] The resin film with a separator according to

[10] above, wherein the release substrate is provided on the first surface, and the surface of the release substrate that is in contact with the first surface has an uneven shape.

[12] The resin film with separator according to

[10] or

[11] , wherein the release substrate is at least one selected from the group consisting of a release film having a film substrate, release paper, mesh material, metal, and prepreg, and the resin constituting the film substrate is at least one selected from the group consisting of polyester resin, polyolefin resin, polyimide resin, fluororesin, silicone resin, liquid crystal polymer, polysulfone resin, cellulose acetate, polyamide resin, polyetheretherketone resin, polyetherketoneketone resin, modified polyphenylene ether, polyphenylene sulfide resin, polycarbonate resin, and polybenzimidazole resin.

[13] A laminate comprising the resin film according to any one of [1] to [9] above and at least one other resin sheet disposed on the first surface of the resin film.

[14] The laminate according to

[13] , wherein the resin constituting the other resin sheet is at least one selected from the group consisting of polyvinyl acetal resin, polyester resin, acetylcellulose resin, polyolefin resin, and polycarbonate resin.

[15] The laminate according to

[13] or

[14] , wherein the other resin sheet includes second and third resin sheets, each disposed on the first surface.

[16] The laminate according to

[15] , wherein the resin constituting the second resin sheet is at least one selected from the group consisting of polyester resin, polyolefin resin, and polycarbonate resin, and the resin constituting the third resin sheet is at least one selected from the group consisting of polyvinyl acetal resin, ethylene-vinyl acetate copolymer resin, urethane resin, and ionomer resin.

[17] The laminate according to any one of

[13] to

[16] , wherein the second surface of the resin film having the uneven structure on the first surface has a bonding mark, and the surface roughness (Sz) at the bonding mark is 1 μm or more and 120 μm or less.

[18] The laminate according to any one of

[13] to

[17] , wherein the other resin sheet is a second resin sheet having any of a dimming element, a light-emitting element, a polarizing film, a hologram film, and a power supply section.

[19] A light-emitting device comprising a laminate according to any of

[13] to

[18] above, wherein the laminate has a light-emitting element.

[20] Laminated glass comprising a laminate according to any one of

[13] to

[18] above and a glass member.

[21] A method for manufacturing a laminate, comprising the step of overlapping another resin sheet on the first surface of a resin film according to any one of [1] to [9] above so as to be in contact with the first surface.

[22] A method for manufacturing a laminate according to

[21] above, further comprising the step of temporarily joining the resin film and the other resin sheet by ultrasonic bonding.

[23] A method for manufacturing a laminate according to

[22] above, wherein the surface roughness (Rzjis) of the surface of the horn or anvil that is in contact with the resin film among the horn or anvil used for ultrasonic bonding is 5 μm or more and 100 μm or less.

[0012] The present invention provides a resin film that exhibits good positional adjustment performance when laminating various components such as functional layers onto the resin film, and that is less prone to unintended positional displacement of the various components after lamination.

[0013] This is a graph showing an example of a load curve. This is a schematic diagram that virtually shows what happens when a planar virtual member is placed above the first surface of the resin film and the virtual member is moved closer to the resin film. This is a schematic cross-sectional view showing an example of a resin film with separators. This is a schematic cross-sectional view showing another example of a resin film with separators. This is a schematic diagram showing a manufacturing apparatus for manufacturing resin films and resin films with separators. This is a schematic diagram showing another example of a manufacturing apparatus. This is a schematic cross-sectional view showing an example of a laminate. This is a schematic cross-sectional view showing another example of a laminate. This is a schematic cross-sectional view showing an example of laminated glass. This is a schematic diagram showing a method of temporarily bonding a resin film to another resin sheet by ultrasonic bonding. This is a diagram showing a method for measuring the bonding strength of a resin film to another resin sheet, with Figure 11(A) being a top view and Figure 11(B) being a side view.

[0014] The present invention will now be described in detail. <Resin Film> This resin film (hereinafter sometimes simply referred to as "this resin film") is a resin film having a first surface and a second surface, wherein at least the first surface has an uneven surface structure. The first surface is one main surface of the resin film, and the second surface is the main surface of the resin film opposite to the first surface.

[0015] [Uneven Structure] In the present invention, the uneven structure of the first surface is such that the load area ratio Smr(C) at C satisfying the requirements of the following formula (1) is 7% or more and 37% or less. C = Sdc(0.2%) - Spk - (Sk / 5) - 0.5 [μm] (1) (Note that in formula (1), Sdc(0.2%) is the level height at a load area ratio of 0.2%, Spk is the height of the protruding peak, and Sk is the height of the core. Smr(C) is the load area ratio (%) when the level height is C) The resin film having the above-specified uneven structure has good positional adjustment performance when laminating various components such as functional layers and other resin sheets onto the resin film, and unintended positional displacement of the various components after lamination is less likely to occur.

[0016] The load area ratio Smr(C) will be explained below with reference to Figures 1 and 2. Figure 1 shows the load curve S on the first surface. Figure 2 virtually shows what happens when a planar virtual member B is placed above the first surface 50A of the resin film 50 and moved closer to the resin film 50. In Figure 2, the convex parts 51 of the uneven structure on the first surface 50A are emphasized and shown as large, and schematically as triangles. The virtual member B is not particularly limited, but it may be a functional member or another resin sheet, as will be described later.

[0017] The load curve S shown in Figure 1 is a curve that represents the height from 0% to 100% load area ratio (load area ratio Smr(y)) with the vertical axis (y) being height (C) and the horizontal axis (x) being load area ratio. The load area ratio is the ratio of the area occupied by the film (protrusions) at each height position on the first surface 50A. Furthermore, the secant line of the load curve, drawn from 0% load area ratio along the load curve S with a difference of 40% load area ratio, is moved from 0% load area ratio until the position where the slope of the secant line is gentlest is defined as the central part of the load curve. The equivalent line is defined as the line that minimizes the sum of the squares of the deviations in the vertical axis direction relative to the central part, and the portion of the equivalent line included in the height range from 0% to 100% load area ratio is defined as the core, with the height of the core being defined as Sk. The average value of the heights of the protruding peaks that protrude from the core is defined as Spk.

[0018] In equation (1), Sdc (0.2%) is the height position where the load area ratio is 0.2%. The portion where the load area ratio is 0 to 0.2% is the so-called outlier at the edge of 3σ (99.7%). Therefore, as described above, when the virtual member B is moved closer to the resin film 50, as shown by the dotted line in Figure 2, it can be said that this is the height position where the virtual member B substantially begins to contact the protrusion 51 of the resin film 50. Then, the position where the virtual member B is moved further closer to the resin film 50 from that height position (Sdc (0.2%)) by the height of the protruding peak (Spk), 1 / 5 of the height of the core (Sk / 5), and 0.5 μm (i.e., the position where the value of C calculated in equation (1) is obtained) is shown by the solid line in Figure 2, and roughly corresponds to the position of the virtual member B when superimposed on the resin film 50. Therefore, the load area ratio Smr(C) can be said to be roughly the contact area of ​​the resin film with respect to the virtual member B when the virtual member B is superimposed on the resin film 50.

[0019] Here, if the load area ratio Smr(C) is lower than 7%, when other components such as functional layers or other resin sheets are stacked on top of the main resin film, the contact area of ​​the other components with the main resin film cannot be sufficiently secured, making unintended positional misalignment more likely to occur when other components are stacked, resulting in problems such as the position of other components shifting during transport. Also, if the load area ratio Smr(C) is greater than 37%, when other components are stacked on top of the main resin film, the contact area of ​​the other components with the main resin film becomes too large, making it difficult to adjust the position after the other components have been laminated. Therefore, for example, if one tries to lift other components or the main resin film to adjust their position, problems such as wrinkles forming on the main resin film or other components may occur. From the viewpoint of more effectively preventing unintended positional misalignment while further improving positional adjustment performance, the load area ratio Smr(C) is preferably 12% to 34.4%, more preferably 12% to 26.6%, and even more preferably 16% or more.

[0020] Furthermore, the resin film 50 is superimposed on another component, such as a second resin sheet described later, to form a laminate. In this case, the first surface may be temporarily bonded to the second or third resin sheet (also called the adherend) by ultrasonic bonding. By temporarily bonding the resin film 50 to another component, displacement of the resin film 50 relative to the other component becomes even easier to prevent. Note that temporary bonding is performed to temporarily fix the resin film 50 to the other component, and the temporarily bonded resin film 50 and the other component are then permanently bonded with even higher bonding strength by methods such as thermocompression bonding.

[0021] Furthermore, when the load area ratio Smr(C) of the first surface is relatively low, misalignment is likely to occur depending on the material of the adherend, but this misalignment can be appropriately prevented by temporary bonding. Specifically, when the load area ratio Smr(C) of the first surface is 7% or more and 12% or less, it is preferable to temporarily bond the first surface to the adherend by ultrasonic bonding from the viewpoint of reliably preventing misalignment. Examples of adherends include the second resin sheet and the third resin sheet described later. That is, specific examples of resins constituting the adherend include resins that can be used in the second resin sheet and the third resin sheet, but misalignment is particularly likely to occur in the case of polyester resin, especially PET. For this reason, when the resin constituting the adherend is polyester resin, especially PET, and the load area ratio Smr(C) of the first surface is 7% or more and 12% or less, it is more preferable to temporarily bond the first surface to the adherend by ultrasonic bonding.

[0022] In a resin film, the height of the protruding peaks (Spk) of the uneven structure of the first surface is preferably 0.4 μm or more and 7 μm or less. Furthermore, the height of the core portion (Sk) of the uneven structure of the first surface is preferably 1.0 μm or more and 10 μm or less. When Spk is 0.4 μm or more, or Sk is 1.0 μm or more, the first surface can be said to have protruding peaks or core portions of a certain height or more, making it easier to adjust the position without the unevenness of the film coming into excessive contact with other components such as functional layers or resin sheets. Also, when Spk is 7 μm or less, or Sk is 10 μm or less, the height of the protruding peaks or core portions does not become too high, and the uneven structure of the film comes into appropriate contact with other components such as functional layers or resin sheets, making it less likely to cause misalignment. The height of the protruding peaks (Spk) of the uneven structure of the first surface is more preferably 0.42 μm or more and 6 μm or less, and even more preferably 0.8 μm or more and 4 μm or less. The height of the core portion (Sk) of the uneven structure of the first surface is more preferably 1.2 μm or more and 9 μm or less, and even more preferably 2.5 μm or more and 8 μm or less. The load area ratio Smr(C), Sk, and Spk can be brought within the above-mentioned predetermined range by appropriately adjusting the height of the unevenness, the number of unevenness, the density of the unevenness, the shape of the unevenness, etc.

[0023] In the present invention, in addition to the first surface, the second surface may also have the above-described uneven structure. That is, the uneven structure of the second surface is preferably such that the load area ratio Smr(C) at C satisfying the requirements of formula (1) above is 7% or more and 37% or less, preferably 12% or more and 34.4%, more preferably 12% or more and 26.6%, and even more preferably 16% or more. Furthermore, the height of the protruding peaks (Spk) and the core portion height (Sk) of the uneven structure of the second surface may be as described for the first surface. By having both the first and second surfaces have the specified uneven structure, even when other members such as functional layers or resin sheets are laminated on either surface of the resin film, the positional adjustment performance is good and unintended positional misalignment is less likely to occur, thus further improving workability.

[0024] Furthermore, the identification of the uneven structure on the first and second surfaces, i.e., the preparation of load curves, and the measurement of Sdc (0.2%), Spk, Sk, and load area ratio Smr(C), etc., should be performed using a three-dimensional roughness meter in accordance with ISO 25178. In addition, if a release substrate is provided on the first and second surfaces, such as in the resin film with separator described later, it is preferable to remove the release substrate and expose the first or second surface before measurement.

[0025] The surface shape of the first surface having an uneven structure is not particularly limited, and may have ridges or grooves formed, with the ridges or grooves arranged regularly. Specifically, it may be a grooved shape with many ridges or grooves arranged in parallel, or a grid shape with multiple ridges or grooves intersecting. It may also be a random shape with many random protrusions or recesses formed. In the case of a random shape, the uneven structure is more preferably a matte finish. The surface shape of the release film is preferably random. By making it a random shape, the bias of the contact surface of the resin film with other components can be reduced. In addition, it becomes easier to adjust the load area ratio Smr(C) at C that satisfies the requirements of formula (1) to within a desired range.

[0026] The uneven structure may be formed, for example, by directly embossing the resin film, but it is preferable that the uneven shape of the release substrate is transferred to it, as will be described later.

[0027] [Thermoplastic Resin] The resin film contains a thermoplastic resin, and more specifically, it is preferably made of a thermoplastic resin composition containing a thermoplastic resin. Examples of thermoplastic resins include polyvinyl acetal resin, polyvinyl alcohol resin (PVA), polyurethane resin (PU), ethylene-vinyl acetate copolymer resin (EVA), ethylene-vinyl acetate copolymer saponified product (EVOH), ethylene-methacrylic acid copolymer resin, (meth)acrylic resin, ionomer resin, isobutylene resin, styrene-isoprene copolymer resin, and styrene-butadiene copolymer resin. These thermoplastic resins may be used individually or in combination of two or more. Among these thermoplastic resins, from the viewpoint of adhesion, ethylene-vinyl acetate copolymer resin, polyvinyl acetal resin, polyurethane resin, and ionomer resin are preferred, ethylene-vinyl acetate copolymer resin (EVA) and polyvinyl acetal resin are more preferred, and from the viewpoint of adhesion to glass, polyvinyl acetal resin is even more preferred, and polyvinyl butyral resin (PVB) is even more preferred. Furthermore, because this resin film has the specified uneven structure described above, it prevents misalignment while also facilitating positional adjustment. Therefore, even with relatively flexible resins such as polyvinyl acetal resin, problems such as wrinkles forming in the resin film during positional adjustment are less likely to occur. The thermoplastic resin used in the thermoplastic resin composition may be used alone or in combination of two or more types.

[0028] (Polyvinyl acetal resin) The polyvinyl acetal resin used as the thermoplastic resin in the thermoplastic resin composition may be a modified polyvinyl acetal resin or an unmodified polyvinyl acetal resin. As described later, the modified polyvinyl acetal resin only needs to have structures other than acetal groups, hydroxyl groups, and acetyl groups (modified groups), and preferably has modified groups in its side chains. Polyvinyl acetal resin is obtained by acetalizing polyvinyl alcohol with an aldehyde and further reacting it with a modifying agent as needed. In addition, to obtain a modified polyvinyl acetal resin, modified polyvinyl alcohol may be used as the raw material polyvinyl alcohol.

[0029] <Degree of Acetalization> The degree of acetalization of polyvinyl acetal resin is preferably 65 mol% or more and 75 mol% or less. When the degree of acetalization of polyvinyl acetal resin is 65 mol% or more, the number of hydroxyl groups in the polyvinyl acetal resin decreases, and the adhesive film becomes sufficiently flexible. Furthermore, when the degree of acetalization of polyvinyl acetal resin is 75 mol% or less, the adhesion to substrates such as inorganic glass becomes good. From this viewpoint, the degree of acetalization of polyvinyl acetal resin is more preferably 67 mol% or more and 74 mol%, even more preferably 68 mol% or more and 73 mol%, and even more preferably 69 mol% or more and 72 mol% or less. Note that when the acetal group is a butyral group and the polyvinyl acetal resin is a polyvinyl butyral resin, the degree of acetalization refers to the degree of butyralization.

[0030] The degree of acetalization described above is a value expressed as a percentage of the mole fraction obtained by dividing the total amount of ethylene groups in the main chain (the difference between the total amount of ethylene groups in the main chain and the amount of ethylene groups to which hydroxyl groups and ethylene groups are to which acetyl groups are to be) by the total amount of ethylene groups in the main chain. The degree of acetalization (degree of butyralization) can be calculated from the results obtained by measuring according to a method such as JIS K6728 "Test Method for Polyvinyl Butyral".

[0031] <Weight-Average Molecular Weight> The weight-average molecular weight (Mw) of the polyvinyl acetal resin is preferably 220,000 or more. When the weight-average molecular weight (Mw) of the polyvinyl acetal resin is 220,000 or more, the impact resistance of the polyvinyl acetal resin can be improved. From this viewpoint, the weight-average molecular weight (Mw) of the polyvinyl acetal resin is more preferably 230,000 or more, even more preferably 240,000 or more, and even more preferably 260,000 or more. Furthermore, the weight-average molecular weight (Mw) of the polyvinyl acetal resin is preferably 310,000 or less. When the weight-average molecular weight (Mw) of the polyvinyl acetal resin is 310,000 or less, the resin film will have sufficient flexibility. In addition, when the adherend is glass, the scattering of glass can be suppressed more effectively. From this perspective, the weight-average molecular weight (Mw) of the polyvinyl acetal resin is more preferably 305,000 or less, even more preferably 300,000 or less, and even more preferably 290,000 or less.

[0032] The weight-average molecular weight (Mw) of polyvinyl acetal resin is measured by gel permeation chromatography. The weight-average molecular weight can be measured by the following method: The sample to be measured is dissolved to a concentration of 0.05% by mass in an N-methyl-2-pyrrolidone solution to which lithium bromide has been added to a concentration of 10 mM, and filtered using a syringe filter (Merck Millex-LH 0.45 μm). After filtration, the measurement is performed using gel permeation chromatography (Waters e2690), and the molecular weight is calculated using a molecular weight calibration curve prepared with monodisperse polystyrene standard samples. A Shodex GPC KF-806L column (Showa Denko Corporation) is used, and an N-methyl-2-pyrrolidone solution to which lithium bromide has been added to a concentration of 10 mM is used as the eluent.

[0033] <Aldehydes> The polyvinyl acetal resin is preferably a polyvinyl acetal resin obtained by acetalizing polyvinyl alcohol (PVA) with an aldehyde. The aldehyde is not particularly limited, but generally, aldehydes having 1 to 10 carbon atoms are preferably used. The aldehydes having 1 to 10 carbon atoms are not particularly limited, and examples include n-butyraldehyde, isobutyraldehyde, n-valeraldehyde, 2-ethylbutyraldehyde, n-hexylaldehyde, n-octylaldehyde, n-nonylaldehyde, n-decylaldehyde, formaldehyde, acetaldehyde, and benzaldehyde. These aldehydes may be used alone or in combination of two or more. Among the above, n-butyraldehyde, n-hexylaldehyde, and n-valeraldehyde are preferred, and n-butyraldehyde is more preferred. Therefore, polyvinyl butyral resin (PVB) is preferred as the polyvinyl acetal resin.

[0034] <Polyvinyl Alcohol (PVA)> Polyvinyl alcohol (PVA), used as a raw material for polyvinyl acetal resin, is obtained by saponifying polyvinyl esters such as polyvinyl acetate. The degree of saponification of polyvinyl alcohol is generally 70 to 99.9 mol%. The average degree of polymerization of PVA is preferably 200 or higher, more preferably 500 or higher, even more preferably 1000 or higher, and even more preferably 1500 or higher. Setting the average degree of polymerization above the above lower limit increases the penetration resistance of laminated glass when used in laminated glass. Furthermore, the average degree of polymerization of PVA is preferably 5000 or lower, more preferably 4000 or lower, even more preferably 3500 or lower, and even more preferably 2500 or lower. The average degree of polymerization of polyvinyl alcohol is determined by a method in accordance with JIS K6726 "Test Method for Polyvinyl Alcohol". Furthermore, when two or more types of polyvinyl alcohol are used as raw materials, the average degree of polymerization of the polyvinyl alcohol can be estimated by calculation from the average degree of polymerization of each polyvinyl alcohol. Furthermore, two or more types of polyvinyl alcohol with different average degrees of polymerization may be used as the raw material for the polyvinyl acetal resin.

[0035] <Hydroxyl Group Content> The hydroxyl group content of polyvinyl acetal resin is preferably 15 mol% or more, and more preferably 38 mol% or less. Setting the hydroxyl group content to 15 mol% or more makes it easier to achieve good adhesion to the adherend. Setting the hydroxyl group content to 38 mol% or less makes it easier to ensure flexibility, further improving the impact absorption of the resin film. The above hydroxyl group content is more preferably 20 mol% or more, and even more preferably 25 mol% or more. Furthermore, the above hydroxyl group content is more preferably 35 mol% or less, and even more preferably 33 mol% or less. When polyvinyl butyral resin is used as the polyvinyl acetal resin, from a similar viewpoint, the hydroxyl group content is 15 mol% or more, and more preferably 38 mol% or less, more preferably 20 mol% or more, even more preferably 25 mol% or more, more preferably 35 mol% or less, and even more preferably 33 mol% or less. The amount of hydroxyl groups in polyvinyl acetal resin is the mole fraction obtained by dividing the amount of ethylene groups to which hydroxyl groups are attached by the total amount of ethylene groups in the main chain, expressed as a percentage. The amount of ethylene groups to which hydroxyl groups are attached can be measured, for example, in accordance with JIS K6728 "Test Method for Polyvinyl Butyral".

[0036] <Degree of Acetylation> The degree of acetylation of the polyvinyl acetal resin is preferably 30 mol% or less, more preferably 20 mol% or less, even more preferably 10 mol% or less, and even more preferably 2 mol% or less. When the degree of acetylation is below the above upper limit, the moisture resistance of the thermoplastic resin composition is increased. Furthermore, the degree of acetylation is not particularly limited, but is preferably 0.01 mol% or more, and more preferably 0.1 mol% or more. The degree of acetylation is a value expressed as a percentage of the mole fraction obtained by dividing the amount of ethylene groups to which the acetyl group is bonded by the total amount of ethylene groups in the main chain. The amount of ethylene groups to which the acetyl group is bonded can be measured, for example, in accordance with JIS K6728 "Test Method for Polyvinyl Butyral".

[0037] <Modified Polyvinyl Acetal Resin> The polyvinyl acetal resin used as the thermoplastic resin in a thermoplastic resin composition is preferably an unmodified polyvinyl acetal resin, but it may also be a modified polyvinyl acetal resin. A modified polyvinyl acetal resin has structures other than acetal groups, hydroxyl groups, and acetyl groups (modified groups), and preferably has modified groups in its side chains. Examples of modified groups include those having a polyalkylene oxide structure in the side chain, and those having alkyl groups other than acetal groups and acetyl groups (for example, with about 2 to 30 carbon atoms) in the side chain. A preferred modified polyvinyl acetal resin is a polyalkylene oxide modified polyvinyl acetal resin, and a more preferred modified polyvinyl acetal resin is a polyethylene oxide modified polyvinyl acetal resin. The amount of modification is not particularly limited, but for example, it is about 0.1 mol% to 10 mol%. The amount of modification represents the ratio of functional groups to the total vinyl monomer units constituting the polyvinyl acetal resin.

[0038] (Method for producing polyvinyl acetal resin) Polyvinyl acetal resin is preferably produced by a manufacturing method that includes a mixing step of mixing the above-mentioned polyvinyl alcohol and the above-mentioned aldehyde, and a maturation step of maturing the mixture obtained in the mixing step.

[0039] In the mixing step, polyvinyl alcohol and aldehyde should be mixed according to the conventional method. In addition to polyvinyl alcohol and aldehyde, catalysts such as acid catalysts to promote the acetalization reaction may be added. For example, the aldehyde can be added to a mixture of polyvinyl alcohol and an acid catalyst under low temperature conditions of about 0 to 40°C. A solvent such as water is also usually added. Furthermore, when using two or more types of polyvinyl alcohol (for example, when using two or more types of polyvinyl alcohol with different molecular weights), it is best to mix the two or more types of polyvinyl alcohol with the aldehyde.

[0040] The above-mentioned aging process is not particularly limited, but for example, a catalyst such as an acid catalyst may be added to the mixture (reaction mixture) obtained in the mixing process, heated to the aging temperature, and held at the aging temperature for a certain period of time. In this manufacturing method, the acetalization of polyvinyl alcohol proceeds in the mixing and aging processes, and polyvinyl acetal resin is obtained. After the reaction mixture is held at the aging temperature for a certain period of time, it may be cooled as appropriate and neutralized, and then washed with water, dried, etc. as needed.

[0041] Examples of acid catalysts added in the mixing and maturation processes include inorganic acids such as hydrochloric acid, nitric acid, phosphoric acid, sulfuric acid, and boric acid. In the maturation process, the concentration of the acid catalyst should be adjusted to, for example, 0.5% by mass or more and 5% by mass or less, preferably 1% by mass or more and 2.5% by mass or less.

[0042] The maturation temperature in the maturation process is preferably relatively low, for example, 30°C to 68°C, preferably 30°C to 65°C, more preferably 35°C to 60°C, and even more preferably 40°C to 58°C. The time for holding at the above maturation temperature (maturation time) can be longer than a certain period, for example, 75 minutes to 180 minutes, preferably 90 minutes to 150 minutes, and more preferably 100 minutes to 140 minutes.

[0043] (Ethylene-vinyl acetate copolymer resin (EVA)) The ethylene-vinyl acetate copolymer resin may be a non-crosslinked type ethylene-vinyl acetate copolymer resin, or a high-temperature crosslinked type ethylene-vinyl acetate copolymer resin. In addition, ethylene-vinyl acetate modified resins such as ethylene-vinyl acetate copolymer saponified products and hydrolyzed products of ethylene-vinyl acetate can also be used as the ethylene-vinyl acetate copolymer resin.

[0044] The ethylene-vinyl acetate copolymer resin preferably has a vinyl acetate content of 10% by mass or more and 50% by mass or less, more preferably 20% by mass or more and 40% by mass or less, measured in accordance with JIS K6924-2:1997. By setting the vinyl acetate content to be not less than these lower limit values, the adhesiveness of the resin film to the adherend is increased. Further, by setting the vinyl acetate content to be not more than these upper limit values, the breaking strength of the resin film is increased.

[0045] (Plasticizer) The thermoplastic resin composition preferably contains a plasticizer in addition to the thermoplastic resin. By containing a plasticizer in the thermoplastic resin composition, the adhesive film becomes more flexible and the impact absorbency can be further improved. The plasticizer is more preferably contained in the thermoplastic resin composition when the thermoplastic resin is a polyvinyl acetal resin.

[0046] Examples of the plasticizer include organic ester plasticizers, organic phosphorus plasticizers such as organic phosphate plasticizers and organic phosphite plasticizers, polyalkylene glycol-based plasticizers, organic ether-based plasticizers such as polyoxyalkylene ether-based plasticizers, and alcohol-based plasticizers. The plasticizer may be used alone or in combination of two or more. Among the above, organic ester plasticizers and organic ether-based plasticizers are preferred.

[0047] Preferred organic ester plasticizers include monobasic organic acid esters and polybasic organic acid esters. Examples of monobasic organic acid esters include esters of glycol and monobasic organic acid. Examples of glycols include polyalkylene glycols in which each alkylene unit has 2 to 4 carbon atoms, preferably 2 or 3 carbon atoms, and the number of repeating alkylene units is 2 to 10, preferably 2 to 4. Alternatively, the glycol may be a monoalkylene glycol with 2 to 4 carbon atoms, preferably 2 or 3 carbon atoms (i.e., 1 repeating unit). Specific examples of glycols include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, and butylene glycol. Examples of monobasic organic acids include organic acids having 3 to 10 carbon atoms, specifically butyric acid, isobutyric acid, caproic acid, 2-ethylbutyric acid, heptylic acid, n-octylic acid, 2-ethylhexylic acid, n-nonylic acid, and decylic acid.

[0048] Specific monobasic organic acid esters include triethylene glycol di-2-ethylbutyrate, triethylene glycol di-2-ethylhexanoate, triethylene glycol dicaprylate, triethylene glycol di-n-octanoate, triethylene glycol di-n-heptanoate, tetraethylene glycol di-n-heptanoate, tetraethylene glycol di-2-ethylhexanoate, diethylene glycol di-2-ethylbutyrate, diethylene glycol di-2-ethylhexanoate, dipropylene glycol di-2-ethylbutyrate, triethylene glycol di-2-ethylpentanoate, tetraethylene glycol di-2-ethylbutyrate, diethylene glycol dicaprate, triethylene glycol di-n-heptanoate, tetraethylene glycol di-n-heptanoate, triethylene glycol di-2-ethylbutyrate, ethylene glycol di-2-ethylbutyrate, 1,2-propylene glycol di-2-ethylbutyrate, 1,3-propylene glycol di-2-ethylbutyrate, 1,4-butylene glycol di-2-ethylbutyrate, 1,2-butylene glycol di-2-ethylbutyrate, and the like.

[0049] Examples of polybasic organic acid esters include ester compounds of dibasic organic acids having 4 to 12 carbon atoms, such as adipic acid, sebacic acid, and azelaic acid, and alcohols having 4 to 10 carbon atoms. The alcohol having 4 to 10 carbon atoms may be linear, may have a branched structure, or may have a cyclic structure. Specifically, dibutyl sebacate, dioctyl azelate, dihexyl adipate, dioctyl adipate, hexyl cyclohexyl adipate, diisononyl adipate, heptyl nonyl adipate, dibutyl carbitol adipate, mixed adipic acid esters, and the like can be mentioned. Also, oil-modified sebacic acid alkyds and the like may be used. Examples of mixed adipic acid esters include adipic acid esters prepared from two or more alcohols selected from alkyl alcohols having 4 to 9 carbon atoms and cyclic alcohols having 4 to 9 carbon atoms.

[0050] The organic ester plasticizer is not limited to the complete esters of the esters described above, but may also be a partial ester. For example, it may be a partial ester of a glycol and a monobasic organic acid, or a partial ester of a dibasic organic acid and an alcohol. Specifically, examples include triethylene glycol-mono-2-ethylhexanoate. Furthermore, it may be a partial ester of a trivalent or higher alcohol, such as glycerin, and a monobasic organic acid. Examples of monobasic organic acids include those having 3 to 24 carbon atoms, preferably 6 to 18 carbon atoms. Specific examples of partial esters of trivalent or higher alcohols and monobasic organic acids include mono or diesters of glycerin and stearic acid, and mono or diesters of glycerin and 2-ethylhexyl acid. Among the above, triethylene glycol-di-2-ethylhexanoate (3GO) is particularly preferred as the organic ester plasticizer.

[0051] Examples of organophosphorus plasticizers include phosphate esters such as tributoxyethyl phosphate, isodecylphenyl phosphate, and triisopropyl phosphate. Examples of polyalkylene glycol plasticizers include polyethylene glycol, polypropylene glycol (PPG), poly(ethylene oxide / propylene oxide) block copolymer, poly(ethylene oxide / propylene oxide) random copolymer, and polytetramethylene glycol, among which polypropylene glycol (PPG) is preferred.

[0052] Polyoxyalkylene ether plasticizers are ether compounds of a monohydric or polyhydric alcohol and a polyoxyalkylene. Specific examples of polyoxyalkylene ether plasticizers include polyoxyethylene hexyl ether, polyoxyethylene heptyl ether, polyoxyethylene octyl ether, polyoxyethylene-2-ethylhexyl ether, polyoxyethylene nonyl ether, polyoxyethylene decyl ether, polyoxyethylene allyl ether, polyoxyethylene allyl ether, polyoxyethylene glyceryl ether, polyoxypropylene glyceryl ether, polyoxyethylene diglyceryl ether, polyoxypropylene diglyceryl ether (DGP), and polyoxyalkylene pentaerythritol ether. Among these, polyoxypropylene diglyceryl ether (DGP) is preferred. The polyoxyalkylene ether plasticizer is preferably an ether compound of a polyhydric alcohol and a polyoxyalkylene, more preferably an ether compound of glycerin or diglycerin and a polyoxyalkylene, and even more preferably an ether compound of glycerin or diglycerin and a polyoxypropylene. Examples of alcohol-based plasticizers include various polyhydric alcohols such as butanediol, hexanediol, trimethylolpropane, and pentaerythritol. Among these, trimethylolpropane is preferred.

[0053] The above plasticizers can be used individually or in combination of two or more. Among the above plasticizers, triethylene glycol-di-2-ethylhexanoate (3GO), polyoxypropylene diglyceryl ether (DGP), and polypropylene glycol (PPG) are preferred, and triethylene glycol-di-2-ethylhexanoate (3GO) is more preferred.

[0054] The content of plasticizer in the thermoplastic resin composition is not particularly limited, but is preferably 20 parts by mass or more and 70 parts by mass or less per 100 parts by mass of thermoplastic resin. When the plasticizer content is 20 parts by mass or more, the resin film becomes moderately flexible and the adhesion of the resin film to glass plates and the like becomes good. On the other hand, when the plasticizer content is 70 parts by mass or less, separation of the plasticizer from the adhesive film is prevented. The above content of plasticizer is more preferably 25 parts by mass or more, even more preferably 30 parts by mass or more, and more preferably 65 parts by mass or less, even more preferably 60 parts by mass or less, even more preferably 55 parts by mass or less, and even more preferably 50 parts by mass or less.

[0055] The thermoplastic resin composition may contain, in addition to plasticizers, known additives used in combination with thermoplastic resins as appropriate. That is, the thermoplastic resin composition may consist of a thermoplastic resin alone, such as polyvinyl acetal resin, or it may consist of a thermoplastic resin and a plasticizer, but it may also contain additives other than plasticizers as needed. Specifically, additives other than plasticizers include ultraviolet absorbers, infrared absorbers, antioxidants, light stabilizers, adhesion modifiers, colorants (pigments or dyes), fluorescent whitening agents, crystal nucleating agents, etc. However, even when other components are blended into the thermoplastic resin composition, the thermoplastic resin composition is mainly composed of a thermoplastic resin, or the sum of the thermoplastic resin and plasticizer, and the total amount of thermoplastic resin and plasticizer is usually 70% by mass or more, preferably 80% by mass or more and 100% by mass or less, and more preferably 90% by mass or more and 100% by mass or less, based on the total amount of the resin layer.

[0056] The thickness of the resin film is preferably 50 μm or more and 1 mm or less, more preferably 100 μm or more and 760 μm or less, and even more preferably 100 μm or more and 500 μm or less. A thickness of the resin film above the lower limit enhances impact resistance and facilitates adhesion to glass components. On the other hand, a thickness below the upper limit prevents the laminate or laminated glass from becoming unnecessarily thick, making it possible, for example, to place multiple resin films between two glass components in laminated glass.

[0057] The resin film may be a single-layer film having a single-layer structure. When the resin film is composed of a single layer, the single-layer resin film may have the composition described above for the thermoplastic resin composition. That is, the layers constituting the single-layer resin film may contain the thermoplastic resin described above, and may also contain a plasticizer as needed, and may also contain additives other than plasticizers as appropriate.

[0058] The resin film may be a multilayer film with two or more layers. Preferably, each resin layer of the multilayer film has the composition described in the thermoplastic resin composition above. That is, each resin layer preferably contains a thermoplastic resin as described in the thermoplastic resin composition above, and may optionally contain a plasticizer, and may also contain additives other than plasticizers as appropriate. More preferably, each resin layer contains the polyvinyl acetal resin described above as the thermoplastic resin. Details of the thermoplastic resin, plasticizer, and additives in each resin layer of the multilayer film, and the details of the content of each component, are as described in the thermoplastic resin composition above. However, the thermoplastic resin used as the basis for the content is the thermoplastic resin contained in each layer. In a multilayer film, each resin layer may have the same composition or different compositions. Furthermore, in a multilayer film, it is preferable that at least the surface layer constituting the first surface has the composition described in the thermoplastic resin composition above, and it is also preferable that at least the resin layer constituting the surface layer constituting the first surface contains the polyvinyl acetal resin described above as the thermoplastic resin. The details of each component in the surface layer are as described in the thermoplastic resin composition above.

[0059] The method for manufacturing this resin film is not particularly limited and can be manufactured by conventionally known methods, such as extrusion molding or press molding. However, as detailed below, it is preferable to manufacture it by extrusion molding.

[0060] [Separator-type resin film] This resin film may be laminated with a release substrate to form a separator-type resin film. The separator-type resin film comprises this resin film and a release substrate provided on at least one of the first and second surfaces of this resin film. The separator-type resin film can protect the surface of this resin film by having a release substrate. This resin film has the above-described specified uneven structure, and although the unevenness is relatively small, if it is rolled up on its own, the first and second surfaces of this resin film will stick together and become difficult to unwind. However, by making it a separator-type resin film, the first and second surfaces do not come into contact even when rolled up, making it easy to unwind. Furthermore, as described later, by giving the release substrate an uneven shape, an uneven structure can be easily formed on the first or second surface of this resin film.

[0061] As shown in Figure 3, the separator-attached resin film 60 may have release substrates 21 and 22 on both the first surface 50A and the second surface 50B of the resin film 50. Alternatively, the separator-attached resin film 60 may have the release substrate on at least one of the first surface 50A or the second surface 50B. For example, as shown in Figure 4, the release substrate 22 may be provided only on the second surface 50B, or, although not shown, the release substrate 21 may be provided only on the first surface 50A. However, it is preferable that the separator-attached resin film 60 has the release substrate 22 on at least the second surface 50B. When the release substrate 22 is provided on the second surface 50B, the release substrate 22 can be laminated onto the resin film 50 while exposing the first surface 50A having the specific structure described above. Therefore, when laminating other components such as functional layers or resin sheets, which will be described later, onto the first surface 50A, the release substrate 22 can be placed on the second surface 50B, resulting in improved workability and making it less likely for scratches or other damage to occur on the second surface 50B of the resin film 50. In this specification, the release substrate 21 provided on the first surface 50A may be described as the first release substrate, and the release substrate 22 provided on the second surface 50B may be described as the second release substrate.

[0062] The release substrate is not particularly limited as long as it can be peeled off the resin film. Examples of release substrates include release films, release paper, mesh materials, metals, and prepregs. These release substrates can be used individually or in combination of two or more. For example, a release film laminated with a mesh material or metal can also be used. As the first release substrate, a release film is more preferable from the viewpoint of handling ease and further reducing the heat shrinkage rate. The release substrate may have a release layer as appropriate if necessary. For example, a release film has a film substrate and may consist of the film substrate alone, or a release layer may be provided on at least one side of the film substrate. The release layer is preferably provided on the surface of the release substrate that is in contact with the resin film.

[0063] The film substrate constituting the release film can be any known resin film. The resin constituting the film substrate is not particularly limited, but examples include polyester resin, polyolefin resin, polyimide resin, fluororesin such as tetrafluoroethylene, silicone resin, liquid crystal polymer, polysulfone resin, cellulose acetate, polyamide resin, polyether ether ketone resin, polyether ketone ketone resin, modified polyphenylene ether, polyphenylene sulfide resin, polycarbonate resin, or polybenzimidazole resin.

[0064] Examples of polyester resins include polyethylene terephthalate resin (PET), polyethylene terephthalate glycol resin (PETG), polybutylene naphthalate resin (PBN), polybutylene terephthalate resin (PBT), polytrimethylene terephthalate resin (PTT), polyhexamethylene terephthalate resin (PHT), copolymer polyethylene terephthalate / isophthalate resin (PET / PEI), polyethylene naphthalate resin (PEN), and polylactic acid resin. PET, PEN, and PBN are preferred polyester resins, with PET being more preferred. Examples of polyolefin resins include polyethylene resins such as ultra-high molecular weight polyethylene, high-density polyethylene, low-density polyethylene, and linear low-density polyethylene, as well as polypropylene resin, polymethylpentene resin (PMP), and cyclic olefin resin (COP). Among these, polypropylene resin and polymethylpentene resin (PMP) are more preferred.

[0065] Examples of fluororesins include polytetrafluoroethylene (PTFE), polychlorotrifluoroethylene (PCTFE or CTFE), polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), perfluoroalkoxy fluororesin (PFA), tetrafluoroethylene / hexafluoropropylene copolymer (FEP), ethylene / tetrafluoroethylene copolymer (ETFE), ethylene / chlorotrifluoroethylene copolymer (ECTFE), and tetrafluoroethylene / perfluoroalkoxyethylene copolymer. Among these, polytetrafluoroethylene is more preferred. Examples of polysulfone resins include polysulfone (PSU), polyphenylsulfone (PPSU), and polyethersulfone (PES).

[0066] Among the above, polyolefin resin and polyester resin are preferred, and among these, PET, polyethylene resin, polypropylene resin (PP), and polymethylpentene resin are preferred, PET and PP are more preferred, and PET is even more preferred. Therefore, the film substrate constituting the release film is preferably a polyolefin resin film or a polyester resin film, among these, PET film and PP film are more preferred, and PET film is even more preferred. These resins may be used individually or in combination of two or more. The film substrate may also consist of a single layer or have a multilayer structure of two or more layers. In the case of a multilayer structure of two or more layers, the resins constituting each layer may be the same or different. Furthermore, the resin film may be an unstretched film or a stretched film.

[0067] In a release substrate, the release layer is formed by a release agent, which may be a silicone-based release agent or a non-silicone-based release agent. In the case of a silicone-based release agent, a silicone resin is preferably used as the resin in the release agent. Examples of resins used in non-silicone-based release agents include fluororesins, melamine resins, epoxy resins, phenolic resins, and acrylic resins. Among these, silicone-based release agents are preferred. Furthermore, the release substrate may have layers other than the release layer on the side that contacts the resin film. For example, if the adhesion between the release substrate and the resin layer is insufficient, an adhesion adjustment layer formed by a primer such as a urethane resin or polyethylene resin may be provided. Using an adhesion adjustment layer formed by these primers can increase the adhesion strength (peel strength) of the release substrate to the resin film. The thickness of the release layer and the adhesion adjustment layer is not particularly limited, but is preferably 0.01 μm or more and 20 μm or less, more preferably 0.05 μm or more and 10 μm or less, and even more preferably 0.08 μm or more and 5 μm or less.

[0068] As the release paper, any known release paper may be used, preferably one in which a release layer is provided on at least one side of the paper substrate. The release layer is preferably provided on the side on which the resin film is laminated. The release layer is preferably formed by a release agent, and specific examples of release agents are as described above. Furthermore, as the paper substrate used for the release paper, it is preferable to use one that has been processed to prevent the release agent from immersing in the base paper, for example, glassine paper, smear-coated paper, PE laminated paper, or PET laminated paper may be used.

[0069] Furthermore, examples of mesh materials include resin mesh and metal mesh. Resin mesh may be woven or knitted fabrics made of resin fibers, or nonwoven fabrics. The resin used for the resin mesh may be any of the resins listed above for use in the base film. Examples of metal mesh include aluminum mesh, stainless steel mesh, and copper mesh. The metal may be metal foil such as aluminum foil, stainless steel foil, or copper foil, or metal plate. The metal plate only needs to be thin and flexible, and examples include aluminum plate, stainless steel plate, and copper plate. Examples of prepregs include those made by impregnating reinforcing fibers such as glass fiber or carbon fiber with a matrix resin such as epoxy resin, modified polyphenylene ether resin, polyimide resin, or polybenzoxazole resin.

[0070] The release substrate may have an uneven surface on the surface in contact with the resin film. Having an uneven surface allows the release substrate to easily transfer the uneven surface to the resin film, forming an uneven structure on the first or second surface of the resin film. Therefore, in this invention, it is preferable that at least the first release substrate has an uneven surface. The surface shape of the release substrate having an uneven surface may be a configuration in which protrusions and grooves are formed and arranged regularly, and may be engraved or grid-like. Alternatively, it may be a random shape with numerous random recesses and protrusions, in which case the uneven structure is preferably a textured surface.

[0071] The surface shape of the release substrate may be complementary to the surface (first surface or second surface) of the resin film on which the release substrate is laminated. Therefore, if the first surface has the specified uneven structure described above, the first release substrate may also have a complementary uneven shape to match the specified uneven structure. Accordingly, the uneven shape of the first release substrate may be engraved if the uneven structure of the first surface is engraved, or random if the uneven structure of the first surface is random. Similarly, the shape of the second release substrate may be complementary to the second surface. Therefore, if the second surface has the specified uneven structure described above, the second release substrate may also have a complementary uneven shape to match the specified uneven structure. Furthermore, if the second surface does not have the specified uneven structure described above, the surface of the second release substrate does not need to be given an uneven surface by embossing or the like.

[0072] Methods for creating irregularities on the surface of a release film include, for example, the embossing roll method, the calendering roll method, the shape extrusion method, and the melt fracture method. Among these, embossing by the embossing roll method is preferred. In the embossing roll method, it is preferable to create random irregularities on the surface of the roll used for embossing using a blasting agent. Alternatively, after creating random irregularities using a blasting agent, the roll (for example, an iron roll) may be further vertically ground to create an embossing roll that forms random recesses on the surface of the release film, and this embossing roll may be used.

[0073] The thickness of each release substrate is preferably 10 μm to 200 μm. When the thickness of each release substrate is 10 μm to 200 μm, the handling of the separator-attached resin film becomes easier. From this viewpoint, the thickness of each release substrate is more preferably 20 μm to 150 μm, and even more preferably 30 μm to 130 μm.

[0074] [Manufacturing Method] Next, a method for manufacturing the resin film and the resin film with separators will be described. The resin film and the resin film with separators are not particularly limited, but for example, they can be manufactured using the manufacturing apparatus described below. Below, an example of manufacturing a resin film with separators, in which first and second release substrates 21 and 22 are provided on both sides of the resin film, using the manufacturing apparatus 10 shown in Figure 5 will be described in detail.

[0075] The manufacturing apparatus 10 comprises an extruder 11, a mold 12, a feeding mechanism 13, a substrate heating mechanism 14, a laminating mechanism 15, an annealing section 16, a cooling mechanism 17, and a winding mechanism 18. The manufacturing apparatus 10 manufactures a roll-shaped resin film with separators by winding a laminate 25 obtained by laminating the first and second release substrates 21 and 22 fed out from the feeding mechanism 13 with a resin layer 20 for constituting the resin film onto the winding mechanism 18.

[0076] In this embodiment, the manufacturing method involves unwinding the first and second release substrates 21 and 22 and winding them using a winding mechanism 18, all performed between rolls, in a so-called roll-to-roll manner. When the release substrates, separator-attached resin film, etc., are conveyed by the roll-to-roll method, the release substrates and separator-attached resin film are not particularly limited, but for example, they may be conveyed by a pinch roll 41 and guided by a guide roll 42. However, the pinch roll 41 and guide roll 42 shown in Figure 5 are merely examples and are not particularly limited.

[0077] The extruder 11 is not particularly limited as long as it can melt and knead the thermoplastic resin, and may be a single-screw extruder with one screw inside the cylinder, or a twin-screw extruder with two screws in parallel. The thermoplastic resin and other components added as needed are fed into the extruder 11 from the raw material supply port on the upstream side of the cylinder, and are melted and kneaded by the screws inside the cylinder as they are sent downstream. The melted and kneaded thermoplastic resin composition, including the thermoplastic resin, is supplied to a mold 12 connected to the extruder 11. In the mold 12, the thermoplastic resin composition is extruded in a sheet-like form as a resin layer 20 from a die provided in the mold 12 and supplied to the laminating mechanism 15. The temperature at which the thermoplastic resin composition is extruded from the mold 12 (i.e., the temperature of the thermoplastic resin composition at the mold exit) can be appropriately adjusted according to the type of thermoplastic resin, and specifically, it is preferable to set it to a temperature higher than the softening temperature of the thermoplastic resin. For example, when polyvinyl butyral is used as the thermoplastic resin, the extrusion temperature can be set to, for example, about 180 to 220°C.

[0078] In the above description, the thermoplastic resin composition extruded from the mold 12 was described on the premise that a single layer of resin was extruded. However, a co-extrusion method may be employed to extrude multiple layers of resin. When multiple layers of resin are extruded, it is preferable to provide multiple extruders, connect the multiple extruders to the mold 12, and extrude the thermoplastic resin composition from the mold 12 in a manner that results in multiple layers of resin.

[0079] Preferably, the first and second release substrates 21 and 22, which are fed out from the first and second feeding mechanisms 31 and 32 respectively, are heated in a substrate heating mechanism 14 before being supplied to the laminating mechanism 15. Specifically, it is preferable that the first and second release substrates 21 and 22 are heated by the substrate heating mechanism 14 to a temperature above the softening temperature of the resin layer 20. By preheating the first release substrates 21 and 22 to a temperature above the softening temperature, the release substrates 21 and 22 will shrink due to heat before being laminated onto the resin layer 20. Therefore, when the release substrates 21 and 22 are laminated onto the extruded resin layer 20, it is possible to prevent the release substrates 21 and 22 from shrinking due to the heat of the resin layer 20 and causing wrinkles. The substrate heating mechanism 14 is not particularly limited, but examples include a heating roll and a heating space. The substrate heating mechanism 14 may heat the first and second release substrates 21 and 22 in one of the paths supplied from the dispensing mechanism 13 to the laminating mechanism 15. However, the substrate heating mechanism 14 may be omitted, and the release substrates 21 and 22 may be laminated onto the resin layer 20 without heating.

[0080] The laminating mechanism 15 laminates the first and second release substrates 21 and 22, supplied from the dispensing mechanism 13, onto the thermoplastic resin composition (resin layer 20) extruded from the mold 12. The laminating mechanism 15 includes, for example, first and second rolls 35 and 36, as shown in Figure 5, and the thermoplastic resin composition is supplied between the first and second rolls 35 and 36. Between the first and second rolls 35 and 36, the first release substrate 21 and the second release substrate 22, supplied along each roll 35 and 36, are laminated onto both sides of the supplied resin layer 20, respectively, to obtain a laminate 25. The first and second rolls 35 and 36 may also have a temperature control mechanism, such as flowing a fluid like steam, oil, or water inside, or introducing a heater or electromagnetic induction. The first and second release substrates 21 and 22 and the resin layer 20 may be heated by the temperature control mechanism. The temperature control mechanism makes it easier to adjust the temperature during lamination of the first and second release substrates 21 and 22 and the resin layer 20 to a desired range. In this embodiment, the temperature R1 of the resin layer 20 when laminating the first and second release substrates 21 and 22 onto the resin layer 20 is preferably above the softening temperature of the resin layer 20. However, the temperature R1 is not particularly limited, but it is preferable to keep it below a certain level from the viewpoint of preventing the resin layer 20 from softening or melting more than necessary when laminating the resin layer 20 onto the first release substrate 21 and the second release substrate 22.

[0081] The first release substrate 21 is preferably one having an uneven surface structure on the surface in contact with the resin layer 20. This forms the specified uneven surface structure on the first surface of the resin film. In addition to the first release substrate 21, an uneven surface structure may also be formed on the surface of the second release substrate 22 in contact with the resin layer 20. With such a configuration, the specified uneven surface structure can be formed on the second surface as well as the first surface. Details of the release substrate are as described above.

[0082] In the lamination mechanism 15, the laminate 25 obtained by laminating the first and second release substrates 21 and 22 is then maintained at a temperature above the softening temperature of the resin layer 20 in the annealing section 16 and annealed. The laminate 25 is then cooled by the cooling mechanism 17 and then wound into a roll shape as a separator-attached resin film in the winding mechanism 18 to obtain a roll-shaped separator-attached resin film. Here, the laminate 25 may be kept warm or heated by the heating mechanism in the annealing section 16, or it may be slowly cooled in a room temperature environment. The cooling mechanism 17 is not particularly limited, but examples include a cooling roll and a cooling space. Furthermore, the winding mechanism 18 is not particularly limited, and a known winding machine may be used. By annealing the laminate 25, stress relaxation is promoted, the strain generated in the resin layer 20 during extrusion is removed, and shrinkage of the resin layer 20 (resin film 50) due to subsequent cooling can be prevented. Furthermore, the width of the laminate 25 may be adjusted by cutting the ends before it is wound up by the winding mechanism 18, and inspections may be performed as appropriate. Note that the annealing section 16 and the cooling mechanism 17 may be omitted as appropriate.

[0083] It should be noted that the above manufacturing method is just one example, and the product can be manufactured using various other methods. For example, in the laminating mechanism 15 described above, the first and second release substrates 21 and 22 are laminated on both sides of the resin layer 20 on a pair of rolls, but it is not necessary for the release substrates 21 and 22 to be laminated on a pair of rolls. For example, two sets of rolls may be prepared, and one of the first and second release substrates may be laminated on the resin layer between the rolls of the first set of rolls, and the other release substrate may be laminated on the resin layer between the rolls of the second set of rolls.

[0084] Furthermore, in the above manufacturing method, the laminate 25 is wound up with the first and second release substrates 21 and 22 laminated on both sides of the resin layer 20, and a separator-type resin film 60 having release substrates on both sides is obtained. However, at least one of the first and second release substrates 21 and 22 may be peeled off and removed before being wound up by the winding mechanism 18. It is preferable that at least one of the first and second release substrates 21 and 22 be peeled off and removed from the laminate 25 after being cooled by the cooling mechanism 17. This results in a separator-type resin film 60 (see Figure 4) in which the release substrate is provided on only one of the first surface 50A and the second surface 50B of the resin film 50. The release substrate may be peeled off, for example, between the cooling mechanism 17 and the winding mechanism 18, and then peeled off when wound up by a winding roll or the like.

[0085] Furthermore, although the above manufacturing method shows an embodiment in which the first and second release substrates are laminated on both sides of the resin layer, a circumferential belt may be laminated on the resin layer instead of at least one of the first and second release substrates. An example of using a circumferential belt will be specifically described below with reference to Figure 6.

[0086] Figure 6 shows an example in which a circumferential belt 40 is used instead of the first release substrate 21. The circumferential belt 40 may be made endless. When the circumferential belt 40 is used, as described above, the circumferential belt 40 is heated in the substrate heating mechanism 14 and then supplied to the laminating mechanism 15, where it is laminated onto the resin layer 20 to form a laminate 25. The laminate 25 is then sent to the winding mechanism 18 via the annealing section 16 and the cooling mechanism 17. Between the cooling mechanism 17 and the winding mechanism 18, the circumferential belt 40 is peeled off from the resin layer 20, resulting in a laminate 25X in which the substrate (second release substrate 22) is laminated on only one side of the resin layer 20, and the laminate 25X becomes a separator-type resin film 60 (see Figure 4).

[0087] The circumferential belt 40, peeled from the resin layer 20, is preferably heated again by the substrate heating mechanism 14 after circulating as shown in Figure 6, and then supplied to the laminating mechanism 15. As described above, the circumferential belt is not provided on the final resin film 50, but is removed from the resin layer 20 during manufacturing and reused after circulating, thus improving production efficiency. The circumferential belt 40 is not particularly limited, but it is preferable that it is guided by multiple guide rolls 42 or the like while circulating.

[0088] The circumferential belt may have an uneven surface. By using a circumferential belt having an uneven surface, a specific uneven shape is transferred to the resin layer (the resin film), and the specified uneven structure described above can be formed on the surface (first surface) of the resin film. Details of the uneven shape on the circumferential belt are as described in the section on the releaseable substrate.

[0089] In the above, an example in which a circumferential belt 40 is used instead of the first release substrate 21 has been specifically described, but a circumferential belt may also be used instead of the second release substrate 22. In this case, the circumferential belt used instead of the second release substrate 22 may or may not have an uneven shape. Furthermore, the release substrate laminated on only one side of the resin layer 20 (this resin film 50) becomes the first release substrate 21. Moreover, a circumferential belt may be used instead of the first release substrate, and a circumferential belt may also be used instead of the second release substrate. In this case, a resin film consisting of only the resin layer 20 will be obtained. However, one side may be a circumferential belt and the other side a release substrate, and the resin film consisting of only the resin layer 20 may also be obtained by peeling not only the circumferential belt but also the release substrate from the laminate.

[0090] Furthermore, when a circumferential belt is used, the feeding mechanism may be omitted as appropriate. For example, when a circumferential belt 40 is used instead of the first release substrate 21, the first feeding mechanism may be omitted as shown in Figure 6, and the feeding mechanism 13 may consist of a second feeding mechanism 32. Also, when a circumferential belt 40 is used instead of the second release substrate 22, the second feeding mechanism may be omitted.

[0091] The circumferential belt is not particularly limited, but it is preferable that it be composed of at least one belt substrate selected from the group consisting of film substrates, mesh materials, metals, and prepregs. These may be used individually as the circumferential belt, or two or more may be used in combination. For example, a laminate of a film substrate with a mesh material or metal can also be used. Details of the mesh material, metal, and prepreg are as described in the section on release substrates, so those details will be explained here. Furthermore, the resins that make up the film substrate can be those listed as film substrates in the section on release films, but from the viewpoint of durability and other factors, polyether ether ketone resin, polyphenylene sulfide resin, fluororesin, polyimide resin, etc., are more preferable.

[0092] The circumferential belt may also have a release layer as appropriate. Details of the release layer are as described in the section on the releaseable substrate. The release layer is preferably provided on the side of the circumferential belt that is laminated onto the resin layer. The release layer is preferably provided on the surface of the film substrate, but is not particularly limited. The thickness of the circumferential belt is not particularly limited, but is, for example, 50 μm or more and 3000 μm or less, preferably 100 μm or more and 2000 μm or less, and more preferably 150 μm or more and 1000 μm or less.

[0093] In the above description of the manufacturing method, a configuration in which a release substrate or a circumferential belt is laminated on both sides of the resin layer in the laminating mechanism has been shown. However, only one release substrate may be laminated in the laminating mechanism. In that case, the dispensing mechanism 13 consists of one dispensing mechanism, and the release substrate dispensed from that dispensing mechanism is heated in the heating mechanism 14 and then supplied to the laminating mechanism 15, where it is laminated onto the resin layer 20. In this case, the release substrate is typically a first release substrate. Alternatively, only one circumferential belt may be laminated in the laminating mechanism 15 instead of a release substrate. As described above, when only one release substrate or circumferential belt is laminated in the laminating mechanism 15, the laminating mechanism 15 may consist of a pair of rolls 35 and 36, but it may also consist of one roll, on which the release substrate or circumferential belt is laminated onto the resin layer 20. Furthermore, even in an embodiment in which the release substrate is laminated on only one side of the resin layer, as described above, the release substrate may remain laminated on the resin layer 20 without being peeled off and be wound up by the winding mechanism 18. However, the release substrate may be peeled off from the resin layer 20, resulting in a resin film consisting solely of the resin layer 20, which may then be wound up by the winding mechanism 18.

[0094] Furthermore, although the above description shows an embodiment in which a release substrate and a circumferential belt are laminated onto a resin layer obtained by extruding a molten thermoplastic resin composition from a mold 12, the release substrate and circumferential belt may also be laminated onto a resin layer unwound from a winding body that has been pre-processed into a sheet and wound into a roll. In addition, although the above description has described an embodiment in which a bumpy structure is formed using a release substrate and a circumferential belt, the bumpy structure may also be formed by means other than a release substrate and a circumferential belt. For example, the bumpy structure may be directly formed on the resin film by an embossing roll method, a calender roll method, a shape extrusion method, a melt fracture method, etc. In this case, if the resin film is a resin film with a separator, the release substrate may be laminated onto the resin film on which the bumpy structure has been formed, or the bumpy structure may be formed on a resin film on which the release substrate has been laminated.

[0095] Furthermore, although the resin film with separator or the resin film is shown to be wound up by the winding mechanism 18, it is not necessary for them to be wound up by the winding mechanism 18, and they may be cut or punched out as appropriate to form individual sheets.

[0096] [Laminate] The resin film may be configured as a laminate of the present invention by layering another resin sheet or the like on the first surface having the specified uneven structure described above. Here, the other resin sheet may consist of the resin film alone, or it may be a laminate in which another component is further provided on the resin film. In this specification, both the resin film alone and the sheet-like material in which another component is further provided on the resin film are collectively referred to as a resin sheet.

[0097] The laminate of the present invention will be described in detail below with reference to Figures 7 and 8. The laminate 65 may, for example, include a first resin film 50X made of the resin film and another resin sheet 55 placed on the first surface 50A of the first resin film 50X, as shown in Figure 7. When the other resin sheet 55 is placed on the first surface 50A of the resin film (first resin film 50X), the first surface 50A has a predetermined uneven structure as described above, which prevents the resin sheet 55 from shifting position. Furthermore, even if the resin film 50 and the resin sheet 55 are lifted or otherwise adjusted after being placed together, wrinkles and other defects are prevented from occurring in the film 50X and the sheet 55, resulting in good position adjustment functionality. In Figure 7, the first resin film 50X and the other resin sheet 55 are schematically shown to have the same thickness and size, but the size and thickness of the first resin film 50X and the other resin sheet 55 may be different from each other.

[0098] The resin constituting the other resin sheet is not particularly limited, but is preferably a thermoplastic resin. It is preferable to use a resin that can serve as the base film for the functional layer described later, or a resin that has relatively high adhesion to the first resin film 50X. Specifically, examples include the resins listed as usable for this resin film, as well as acetylcellulose resin, polyester resin, polyolefin resin, and polycarbonate resin. Among these, polyvinyl acetal resin, ethylene-vinyl acetate copolymer resin, polyurethane resin, ionomer resin, polyester resin, acetylcellulose resin, polyolefin resin, and polycarbonate resin are preferred. Details of polyvinyl acetal resin, ethylene-vinyl acetate copolymer resin, polyurethane resin, and ionomer resin are as described in the description of this resin film, and details of polyester resin and polyolefin resin are as described in the description of the base film.

[0099] Among the above, polyvinyl acetal resin, polyester resin, acetylcellulose resin, polyolefin resin, and polycarbonate resin are preferred as the resins that constitute the other resin sheet. Among these, using polyvinyl acetal resin makes it easier to improve adhesion with the present resin film. In particular, using polyvinyl acetal resin for the resins that constitute both the present resin film and the other resin sheet makes it easier to improve adhesion. Furthermore, using polyester resin, polyolefin resin, and polycarbonate resin in the other resin sheet can impart relatively high strength to the other resin sheet, and can be suitably used, for example, as a base film for the functional layer described later. The resins that constitute the other resin sheet may be used individually or in combination of two or more. It is preferable that the resins that constitute the resin film in the other resin sheet are the above-mentioned resins.

[0100] The thickness of the other resin sheet 55 is not particularly limited, but is preferably 1 μm or more and 1000 μm or less, more preferably 10 μm or more and 800 μm or less, and even more preferably 50 μm or more and 500 μm or less.

[0101] Another resin sheet may have layers on its surface such as an anti-reflective layer, a brightness-enhancing layer, a hard coat layer, a forward-scattering layer, an anti-glare layer, an anti-fouling layer, an anti-static layer, and an adhesion-adjusting layer. These layers can be formed on the surface of another resin sheet by conventionally known methods.

[0102] Furthermore, as shown in Figure 8, the laminate 65 may be provided with multiple resin sheets as separate resin sheets. For example, a second resin sheet 55X and a third resin sheet 55Y may be arranged on the first surface 50A as separate resin sheets. Even when multiple resin sheets are arranged on the first surface 50A in this way, the first surface 50A has the specified uneven structure as described above, which prevents any of the resin sheets from shifting position and allows for easy position adjustment, thus enabling accurate alignment. Therefore, the second resin sheet 55X and the third resin sheet 55Y can be easily positioned at the desired location on the first surface 50A, and it is possible to prevent gaps from forming between the second resin sheet 55X and the third resin sheet 55Y, for example.

[0103] Here, the resins constituting the second and third resin sheets 55X and 55Y may be appropriately selected from the resins exemplified in the other resin sheets described above, but the second resin sheet 55X is preferably a laminate including a functional layer and a base film for the functional layer, as will be described later. Therefore, among the above resins, it is preferable to use polyester resin, polyolefin resin, and polycarbonate resin for the resin constituting the second resin sheet 55X. The resin constituting the second resin sheet 55X may be used alone or two or more may be used in combination. In addition, it is preferable that the resin in the resin film of the second resin sheet 55X is one of the above resins.

[0104] On the other hand, the third resin sheet 55Y may, for example, constitute a spacer in the laminate 65 of the present invention, and may be appropriately selected from the resins exemplified in the present resin film, but it is preferable to use a resin that has relatively high adhesion to the present resin film (first resin film 50X), and among these, polyvinyl acetal resin, ethylene-vinyl acetate copolymer resin, polyurethane resin, and ionomer resin are preferred, and among these, polyvinyl acetal resin is more preferred. The spacer may be made of a resin film. Furthermore, from the viewpoint of further improving adhesion, it is preferable that the resins constituting the first resin film 50X and the third resin sheet 55Y are both of the same type, and it is even more preferable that the resins constituting the first resin film 50X and the third resin sheet 55Y are both polyvinyl acetal resins. The resin in the resin film of the third resin sheet 55Y may be one of the above resins.

[0105] Furthermore, the polyvinyl acetal resin used in the other resin sheet 55, the second and third resin sheets 55X and 55Y is preferably polyvinyl butyral (PVB), the polyester resin is preferably PET or PEN, and the polyolefin resin is preferably polypropylene resin (PP). The resin constituting the other resin sheet 55 is more preferably PVB, PET, PEN, PP, or PC. Furthermore, the resin constituting the second resin sheet 55X is more preferably PET, PEN, PP, or PC, with PET being particularly preferred among these. Furthermore, the resin constituting the third resin sheet 55Y is particularly preferably PVB. The thickness of the second resin sheet 55X is not particularly limited, but is preferably 1 μm or more and 1000 μm or less, more preferably 10 μm or more and 800 μm or less, and even more preferably 50 μm or more and 500 μm or less.

[0106] In the laminate 65, the second surface 50B of the first resin film 50X may have a bonding mark. The first surface 50A of the first resin film 50X may be temporarily bonded to another resin sheet by ultrasonic bonding, as described later. When temporarily bonded by ultrasonic bonding, a bonding mark is formed on the second surface 50B that the anvil or horn contacts. Therefore, the presence of a bonding mark on the second surface 50B means that the first surface 50A has been temporarily bonded to another resin sheet by ultrasonic bonding. Ultrasonic bonding may be performed on only a portion of the contact surface between the first surface 50A and the other resin sheet, and the bonding mark may also be provided on a portion of the second surface 50B. The bonding mark is located at a corresponding position on the second surface 50B that overlaps with the temporarily bonded resin sheet when viewed in the thickness direction. Therefore, for example, when the second resin sheet 55X is temporarily joined to the first surface 50A, the joining mark is provided at a position that overlaps with the second resin sheet 55X when viewed in the thickness direction, and when the third resin sheet 55Y is temporarily joined to the first surface 50A, the joining mark is provided at a position that overlaps with the third resin sheet 55Y when viewed in the thickness direction.

[0107] Furthermore, when ultrasonic bonding, as described later, is used, the bonded area has a certain surface roughness. Specifically, the surface roughness (Sz) of the bonded area is preferably 1 μm or more and 120 μm or less, and more preferably 5 μm or more and 100 μm or less. The bonded area having the above surface roughness (Sz) indicates that the resin film has been bonded to another resin sheet by ultrasonic bonding.

[0108] When ultrasonic bonding is performed, if the laminate 65 is arranged on the first surface 50A as shown in Figure 8, with two or more other resin sheets (second and third resin sheets 55X, 55Y), it is preferable that at least one is bonded by ultrasonic bonding, but all resin sheets may also be bonded by ultrasonic bonding. However, it is preferable that at least the second resin sheet 55X is temporarily bonded to the first surface 50A by ultrasonic bonding. The second resin sheet 55X in Figure 8 has a functional layer and a base film in the functional layer, for example, as will be described later, and therefore may have low adhesion to the first resin film 50X and be prone to misalignment. By temporarily bonding the second resin sheet 55X and the first resin film 50X by ultrasonic bonding, misalignment can be prevented more effectively. Furthermore, ultrasonic bonding generally heats only the bonding area, preventing the entire resin film or other resin sheets from being heated and shrinking, and effectively preventing misalignment due to thermal shrinkage that occurs during bonding.

[0109] In another resin sheet 55, it is preferable that the surface layer in contact with the first surface 50A is a resin film. Therefore, for example, the second resin sheet 55X may also be composed of a single sheet or additional components as appropriate, and in that case as well, it is preferable that the resin film is the surface layer in contact with the first surface 50A. The same applies to the third resin sheet 55Y. The resin constituting the resin film that forms the surface layer of the resin sheet 55 (or resin sheets 55X and 55Y) is as described in the description of the resins constituting each of the above resin sheets.

[0110] Here, the resin sheet may have a functional layer, which will be described later, and it is preferable that the second resin sheet has a functional layer. The functional layer is formed by laminating a functional member having a predetermined function within another resin sheet 55 (or the second resin sheet 55X), and the functional layer may further include a fourth resin film laminated on top of the functional member. That is, the resin sheet having a functional layer may have a laminated structure of a resin film (base film of the functional layer) and a functional member, or a laminated structure of a resin film (base film of the functional layer), a functional member, and a fourth resin film. The resin constituting the fourth resin film placed on top of the functional member is as described for the resin constituting the second resin sheet 55X. In Figures 7 and 8, for convenience, the functional member and the fourth resin film are not shown on the other resin sheet 55 or the second resin sheet 55X, but even in the configuration of Figures 7 and 8, the functional member, the fourth resin film, etc. may be appropriately provided on the other resin sheet 55 or the second resin sheet 55X. In other words, in Figures 7 and 8, a resin sheet having a functional layer (a laminate having a functional member) may be provided as another resin sheet 55, or a second resin sheet 55X. In another embodiment, instead of the other resin sheet in Figures 7 and 8, a functional member alone or a laminate including a functional member without a resin film may be used.

[0111] Examples of functional components include electronic components such as dimming elements, light-emitting elements, and solar cell elements, optical films such as polarizing films, phase difference films, anti-reflective films, and holographic films, and power supply units. Among these, dimming elements, light-emitting elements, polarizing films, holographic films, and power supply units are preferred. In a resin sheet having a functional layer, there may be one functional component or two or more. A dimming element is typically a dimming layer disposed between two resin films (for example, a base film of the functional layer and a fourth resin film). In the case of a dimming element, conductive layers are preferably formed on the two resin films. The dimming layer changes the visible light transmittance by switching between applying and not applying a voltage between the conductive layers of the two resin films. The dimming layer may be composed of a liquid crystal layer such as polymer-dispersed liquid crystal (PDLC), or it may be composed of an SPD (Suspended Particle Device), an electrochromic film, an electrophoretic film device, or a GHLC (Guest Host Liquid Crystal). The light-adjusting layer may also be a GHLC layer made of a G-H (guest-host) material doped with a dye.

[0112] Examples of light-emitting elements include organic EL elements and LEDs, and they may be in film form or other forms. Furthermore, the light-emitting elements may constitute display elements such as organic EL elements, LED displays, and segment displays. The solar cell elements are not particularly limited, but examples include crystalline or thin-film silicon solar cell elements, compound semiconductor solar cell elements such as CIS, CIGS, CdTe, and GaAs, and organic solar cell elements such as dye-sensitized, organic thin-film, and perovskite. By using solar cell elements, laminated glass can be made, for example, for building-integrated photovoltaics (BIPV).

[0113] The power supply unit is for supplying current to various electronic components and includes power supply wiring and a wireless power supply unit. The power supply unit may be arranged together with the electronic components on another resin sheet 55 (or a second resin sheet 55X). The power supply wiring may have electrical wiring connected to the electronic components. The electrical wiring may be formed on the resin sheet 55, the second resin sheet 55X, or a fourth resin film. The electrical wiring may extend to the periphery of the resin sheet 55, the second resin sheet 55X, or the fourth resin film, be connected to a connector provided on the periphery, and be connected to an external power supply provided outside the laminate via the connector. An example of a wireless power supply unit is one equipped with an antenna. The antenna may be capable of receiving power from an external source without contact, and may be of electromagnetic induction type, magnetic resonance type, or other types. The antenna is generally composed of a coil. The antenna may be formed from a metallic material such as metal paste, for example by printing. The antenna may be connected to various electronic components via electrical wiring formed on, for example, the resin sheet 55, the second resin sheet 55X, or the fourth resin film.

[0114] The thickness of the functional layer is not particularly limited, but is, for example, 10 μm to 1500 μm, preferably 50 μm to 1000 μm, more preferably 100 μm to 800 μm, even more preferably 100 μm to 700 μm, and even more preferably 100 μm to 400 μm. Note that the thickness of the functional layer may vary depending on the location, but if the thickness changes, it refers to the maximum thickness. The same applies to the thickness of the resin sheet having the above-described functional layer.

[0115] The third resin sheet 55Y is placed on the first surface 50A of the first resin film 50X as described above, and is aligned with the second resin sheet 55X on the first surface 50A. The third resin sheet 55Y can be used, for example, as a spacer. Generally, resin sheets with a functional layer (second resin sheet 55X) often have a smaller projected area in the thickness direction compared to the first resin film 50X. Therefore, even if a resin sheet with a functional layer (second resin sheet 55X) is placed on the first resin film 50X, there is often a space on the first surface 50A where the resin sheet with a functional layer (second resin sheet 55X) is not provided. For this reason, the space can be filled by placing the third resin sheet 55Y together with the resin sheet with a functional layer (second resin sheet 55X) on the first surface 50A. Therefore, when a resin sheet having a functional layer (second resin sheet 55X) is sandwiched between the first resin film 50X and the fifth resin film 58 (described later) as described above, and embedded inside the resin film, no steps or other irregularities are formed on the surface of the laminate 65, and the functional layer and other elements can be properly embedded inside the resin film.

[0116] In Figure 8, the second and third resin sheets 55X and 55Y are schematically shown to be arranged side by side. Preferably, the third resin sheet 55Y is molded into a frame shape with an internal space, and the second resin sheet 55X is placed inside it. The frame shape may be, for example, a rectangular frame.

[0117] As shown in Figures 7 and 8, the laminate 65 may further include a fifth resin film 58. The fifth resin film 58 may have another resin sheet 55 (or second and third resin sheets 55X, 55Y) or a functional layer placed between it and the first resin film 50X. By using the fifth resin film 58, the functional layer and the like can be properly enclosed inside the resin film. In addition, it becomes easier to adhere the laminate 65 to a glass member or the like, which will be described later.

[0118] The third resin sheet 55Y described above contains a thermoplastic resin, and more specifically, it is preferably composed of a thermoplastic resin composition containing a thermoplastic resin. Here, the type of thermoplastic resin used in the third resin sheet 55Y and the composition of the third resin sheet 55Y are not particularly limited, but the above-mentioned resin film can be suitably used, and its composition is as described above. However, the third resin sheet 55Y is preferably about the same thickness as the second resin sheet, preferably 10 μm or more and 1500 μm or less, more preferably 50 μm or more and 1000 μm or less, and even more preferably 100 μm or more and 800 μm or less. The absolute value of the difference between the thickness of the second resin sheet 55X and the thickness of the third resin sheet 55X is not particularly limited, but is preferably 200 μm or less, more preferably 100 μm or less, even more preferably 50 μm or less, even more preferably 40 μm or less, and even more preferably 20 μm or less. If the absolute difference between the thickness of the second resin sheet 55X and the thickness of the third resin sheet 55Y is small, for example 100 μm or less, then steps at the interface formed by the second resin sheet 55X and the third resin sheet 55Y (for example, surface 50A and the surface in contact with the fifth resin film 58) are suppressed. As a result, steps and other irregularities are less likely to occur on the surface of the laminate 65, and functional layers can be appropriately embedded inside the resin film.

[0119] Furthermore, the first resin film 50X has a specified uneven surface on at least one first surface, as described above, such that the load area ratio Smr(C) is within a certain range. However, the third resin sheet 55Y does not necessarily have a first surface having the specified uneven surface. However, the third resin sheet 55Y may have a first surface having the specified uneven surface, or it may have first and second surfaces having the specified uneven surface. The first surface of the third resin sheet 55Y may be the surface that abuts the first resin film 50X, in which case the second surface may be the surface that abuts the fifth resin film 58. Alternatively, the second surface may be the surface that abuts the first resin film 50X, in which case the first surface may be the surface that abuts the fifth resin film 58. The third resin sheet 55Y has a first surface having a specified uneven structure, or a first surface and a second surface, which prevents misalignment when it is superimposed on the first resin film 50X or the fifth resin film 58, and also facilitates position adjustment.

[0120] Furthermore, as described above, if the third resin sheet 55Y has a first surface having a specified uneven structure, or a first surface and a second surface, then the first resin film 50X described above does not need to have a first surface 50A having a specified uneven structure. In other words, in the laminate 65, the third resin sheet may become the main resin film, and the first resin film may become another resin sheet.

[0121] The fifth resin film 58 contains a thermoplastic resin, and more specifically, it is preferably made of a thermoplastic resin composition containing a thermoplastic resin. Here, the type of thermoplastic resin used in the fifth resin film, the composition of the fifth resin film, etc., are not particularly limited, but the above-described resin film can be suitably used, and its composition is as described above. However, the above-described resin film has at least one first surface which has a specified uneven structure such that the load area ratio Smr(C) is within a certain range, as described above, but the fifth resin film does not have to have a first surface which has a specified uneven structure. However, the fifth resin film 58 may have a first surface which has a specified uneven structure, or it may have first and second surfaces which have a specified uneven structure. In this case, it is preferable that the first surface is positioned to face the first resin film 50X side. Furthermore, the fifth resin film 58 is preferably configured such that the first surface having a defined uneven structure abuts against a member (such as a third resin sheet, a functional layer, a second resin sheet, or a fourth resin film) placed between the first resin film 50X and the fifth resin film 58. This configuration prevents misalignment when the fifth resin film is superimposed on the third resin sheet, second resin sheet, fourth resin film, etc., and also facilitates position adjustment. In addition, in the present invention, if the fifth resin film has a first surface having a defined uneven structure as described above, the first resin film and the third resin sheet do not need to have a first surface having a defined uneven structure.

[0122] The laminate of the present invention can provide various devices depending on the type of functional layer provided in the laminate. For example, if the functional layer has a light-emitting element, a light-emitting device can be provided. Also, if the functional layer has a dimming element, a dimming device can be provided, and if the functional layer has a solar cell element, a solar cell device can be provided. Furthermore, if the functional layer has a display element, a display device can be provided.

[0123] [Laminated Glass] The laminate of the present invention may be laminated onto a glass member to form laminated glass. That is, it is preferable that the laminate of the present invention be placed between two glass members and used as an interlayer for laminated glass to join the two glass members. Accordingly, as shown in Figure 9, the present invention also provides laminated glass 70 having first and second glass members 61, 62 and a laminate 65 placed between the first and second glass members 61, 62. Although Figure 9 shows a configuration in which the laminate shown in Figure 7 is used as laminated glass, of course, the laminate shown in Figure 8 may also be used as laminated glass, and in laminated glass, the laminate may have a configuration other than that shown in Figures 7 and 8. In laminated glass 70, the layers of the laminate 65 that are in contact in the thickness direction are bonded to each other and integrated to form an interlayer for laminated glass. In other words, the resin film (first resin film 50X) is bonded to another resin sheet 55 (or second and third resin sheets 55X, 55Y), and the fifth resin film 58 is bonded to another resin sheet 55 (or second and third resin sheets 55X, 55Y), or to a functional layer, and integrated. Furthermore, the first and fifth resin films 50X, 58 are each bonded to the first and second glass members 61, 62, respectively, thereby joining the first and second glass members 61, 62 via the laminate 65.

[0124] The first and second glass members may be glass plates. The glass plates may be either inorganic glass or organic glass, but inorganic glass is preferred. Inorganic glass is not particularly limited, but examples include clear glass, float glass, tempered glass, colored glass, polished glass, patterned glass, wired glass, reinforced glass, ultraviolet absorbing glass, infrared reflective glass, infrared absorbing glass, green glass, etc. Organic glass is generally what is called resin glass, and examples include polycarbonate plates, (meth)acrylic plates such as polymethyl methacrylate plates, polyester plates such as acrylonitrile styrene copolymer plates, acrylonitrile butadiene styrene copolymer plates, polyethylene terephthalate plates, fluororesin plates, polyvinyl chloride plates, chlorinated polyvinyl chloride plates, polypropylene plates, polystyrene plates, polysulfone plates, epoxy resin plates, phenolic resin plates, unsaturated polyester resin plates, polyimide resin plates, etc. Various organic glass plates may be subjected to surface treatment as appropriate.

[0125] Furthermore, the thickness of the first and second glass members is not particularly limited, but is, for example, about 0.1 to 15 mm, preferably 0.5 to 5 mm. The thicknesses of each glass member may be the same or different.

[0126] Furthermore, the laminate of the present invention may be used for materials other than laminated glass, and the first resin film and the fifth resin film may be used in combination with the glass member or other materials as described above.

[0127] <Method for Manufacturing Laminates and Laminated Glass> Next, a method for manufacturing laminates and laminated glass will be described. The method for manufacturing a laminate of the present invention includes the step of overlapping another resin sheet (for example, a second resin sheet) on a first surface of the resin film (for example, a first resin film) so as to be in contact with the first surface. In this case, if the resin film is a resin film with a separator, it is preferable to peel off the first release substrate to expose the first surface before overlapping the other resin sheet on the first surface. However, if the resin film with a separator has a second release substrate, the second release substrate may remain laminated on the resin film while the other resin sheet is overlapped on the first surface, or the second release substrate may be peeled off before the other resin sheet is overlapped on the first surface. However, when ultrasonic bonding is performed as described later, it is preferable to peel off the second release substrate from the second surface before ultrasonic bonding. Also, if the resin film or the resin film with a separator is wound in a roll, it may be unwound from the roll and the process may be performed while it is in a long length. Furthermore, while the resin film and the resin film with separator may be pre-cut into sheets before performing this process, it is preferable to perform this process using the resin film in sheet form. Performing this process using the resin film in sheet form makes it easy to obtain a laminate even if the structure of the laminate is complex, such as when multiple resin sheets are stacked side by side on the first surface.

[0128] For example, in the laminate 65 shown in Figure 7, it is preferable that another resin sheet 55 be superimposed on the first resin film 50X so as to be in contact with the first surface 50A. Here, the other resin sheet 55 may constitute a functional layer or a resin sheet. In that case, it is preferable that the functional layer or resin sheet be superimposed on the first resin film 50X so as to be in contact with the first surface 50A of the first resin film 50X.

[0129] Furthermore, for example, when obtaining the laminate 65 shown in Figure 8, in this step, it is preferable that the second resin sheet 55X and the third resin sheet 55Y are layered on the first resin film 50X so as to abut the first surface 50A. Here, the second resin sheet 55X generally constitutes a second resin sheet having a functional layer. Therefore, it is preferable that the second resin sheet is laminated on the first resin film 50X so as to abut the first surface 50A of the first resin film 50X.

[0130] In this manufacturing method, it is preferable that another resin sheet be aligned and superimposed on the first surface of the resin film (first resin film). That is, when the other resin sheet is superimposed on the resin film, it is superimposed so that it is positioned in a predetermined location relative to the resin film. If it is not possible to position it in the predetermined location, it is preferable that the position of the other resin sheet be adjusted so that it is positioned in the predetermined location relative to the resin film. The position adjustment is not particularly limited, but it may be done, for example, by appropriately lifting the other resin sheet or the resin film and superimposing them again. Since the first surface of the resin film has a predetermined uneven structure and has good position adjustment function, even if the position is adjusted as described above, it can be easily adjusted without wrinkles appearing in the resin film or the other resin sheet. For this reason, for example, as shown in Figure 7, if the size of the resin film (first resin film 50X) and the other resin sheet (second resin sheet 55) are the same, the positions of the outer edges of the resin film 50 and the resin sheet 55 can be easily aligned. Furthermore, for example, as shown in Figure 8, when multiple resin sheets (second and third resin sheets 55X, 55Y) are stacked on the first surface 50A of the resin film (first resin film 50X), they can be properly arranged without creating almost any gaps between them.

[0131] Furthermore, this resin film has the specified uneven structure described above, which makes it less likely for misalignment to occur when another resin sheet is placed on top of it. Therefore, for example, even if another resin sheet is placed on top of the resin film and then transported, misalignment is less likely to occur.

[0132] Furthermore, the process may include a step in which, after another resin sheet is placed on top of the resin film, the resin film and the other resin sheet are joined by ultrasonic bonding. By joining the resin films by ultrasonic bonding, misalignment becomes even less likely. It is preferable that the ultrasonic bonding be performed after the resin film and the other resin sheet have been aligned.

[0133] Here, ultrasonic bonding is preferably performed using a horn 71 and an anvil 72, as shown in Figure 10. The horn 71 and anvil 72 are preferably positioned so that one end is in contact with the second surface 50B of the resin film and the other end is in contact with the back surface of the other member (the surface opposite to the surface in contact with the resin film 50) when the resin film (first resin film 50X) and another member (for example, a second resin sheet 55X) are superimposed, as shown in Figure 10. The horn 71 and anvil 72 positioned as described above transmit vibration energy through ultrasonic vibration to the contact surface between the resin film 50 and the other member, and the first surface 50A can be bonded to the other member by frictional heat.

[0134] In ultrasonic bonding, it is preferable that the surface roughness (Rzjis) of the horn 71 or anvil 72 that contacts the resin film 50 (second surface 50B) is between 5 μm and 100 μm. When the surface roughness (Rzjis) is within the above range, vibration energy is appropriately transmitted to the contact surface between the resin film 50 and another member, allowing the other member to be easily bonded to the first surface 50A. More preferably, the surface roughness (Rzjis) of the horn 71 or anvil 72 is between 10 μm and 90 μm, and even more preferably 70 μm or less. Figure 10 shows a configuration in which the horn 71 is in contact with the second surface 50B of the resin film 50 and the anvil 72 is in contact with another member (second resin sheet 55X). In this configuration, it is preferable that the surface roughness (Rzjis) of the surface of the horn 71 that contacts the second surface 50B is within the above range. However, the horn 71 and the anvil 72 may be reversed, in which case the surface roughness (Rzjis) of the surface of the anvil 72 in contact with the second surface 50B should be within the above range. Furthermore, the horn 71 or anvil 72 may have a number of protrusions formed on its surface, for example, so that the surface roughness (Rzjis) is within the above range. The protrusions may be random or regularly arranged. The surface roughness (Rzjis) of the surface of the horn or anvil is determined by measuring the ten-point average roughness of the surface of the horn or anvil in accordance with JIS B 0601-1994. The measurement is performed using a surface roughness measuring instrument (Surfcoder SE300, manufactured by Kosaka Laboratory Co., Ltd., or an equivalent), with a palpation needle feed speed of 0.5 mm / second, a stylus shape with a tip radius of 2 μm and a tip angle of 60°. The cutoff value, reference length, measurement length, and reserve length can be set as appropriate according to the object being measured. For example, the cutoff value can be 0.8 mm, the reference length 0.8 mm, the measurement length 4 mm, and the reserve length 0.8 mm.

[0135] Furthermore, if the laminate of the present invention further comprises another resin sheet or component, it is preferable to further layer the resin film or component on top of the laminate of the resin film and the other resin sheet. For example, in the laminate shown in Figure 7, it is preferable to further layer the fifth resin film 58 on top of the second resin sheet 55X, and in the laminate shown in Figure 8, it is preferable to further layer the fifth resin film 58 on top of the second resin sheet 55X and the third resin sheet 55Y. In this case as well, if necessary, the surface of the fifth resin film 58 that abuts the second resin sheet 55X and the surface of the third resin sheet 55Y that abuts the fifth resin film 58 may have a specified uneven structure, thereby preventing misalignment between the fifth resin film and the third or second resin sheet, improving the position adjustment function, and allowing the fifth resin film to be easily positioned in the desired location.

[0136] The laminate 65 obtained as described above is then placed between two glass members and heat-pressed to obtain laminated glass. Here, the laminate 65 is integrated by heat-pressure bonding. Therefore, in the laminate 65, the spaces between each layer (for example, between the main resin film and another resin sheet) are not bonded, or are only temporarily bonded, but it is preferable to permanently bond them by heat-pressure bonding. That is, it is preferable to bond the main resin film and the other resin sheet with a higher bonding strength than when temporarily bonded. The laminate 65 can also be applied to materials other than laminated glass, and in that case as well, it is preferable to bond the laminate 65 to the glass members or other materials by heat-pressure bonding. Furthermore, it is preferable to bond the main resin film and the other resin sheet with a higher bonding strength than when temporarily bonded by heat-pressure bonding.

[0137] The present invention will be described in more detail by reference to examples, but the present invention is not limited in any way by these examples. The methods for measuring and evaluating each physical property in the present invention are as follows.

[0138] [Surface Evaluation of Uneven Structure] The uneven structure of the resin film surface was measured using a non-contact 3D white light interference microscope (BURUKER AXS, product name "CountourGT-K1"). Measurement and image processing were performed under the following conditions, and a load curve was created in accordance with ISO 25178:2012 to determine Sdc (0.2%), protruding peak height (Spk), and core height (Sk). C was then calculated according to equation (1), and the load area ratio Smr(C) was determined. <Measurement conditions> Measurement range: 2 mm x 2 mm, objective lens: 10x, internal lens: 0.55x, measured in VSI mode. <Image processing conditions> The analysis software "Vision64" included with the device was used. The following 1st to 3rd processes were performed as flattening processes. Specifically, the first step was to perform the "Terms Removal (F-Operator)" process on Analysis Toolbox with the analysis condition "Tilt only (Plane Fit)". The second step was to perform the "Statistical Filter" process with the analysis conditions "Filter type: Sigma" and "Filter size: 5". The third step was to perform the "data Restore" process with the analysis condition "Legacy" selected, the RestoreEdge condition selected, and the Iteration condition set to 200.

[0139] [Surface roughness (Sz) at the joint marks] The surface roughness (Sz) at the joint marks was determined by measuring under the same measurement conditions as the surface evaluation of the uneven structure described above, in accordance with ISO 25178.

[0140] [Surface roughness (Rzjis) of the horn or anvil surface] In accordance with JIS B 0601-1994, the surface roughness (Rzjis) was determined by measuring the ten-point average roughness of the horn surface. The measurement was performed using a Surfcoder SE300 (manufactured by Kosaka Laboratory Co., Ltd.), with a needle feed speed of 0.5 mm / second, a needle shape with a tip radius of 2 μm and a tip angle of 60°. The cutoff value was 0.8 mm, the reference length was 0.8 mm, the measurement length was 4 mm, and the reserve length was 0.8 mm.

[0141] [Bonding Strength (Without Ultrasonic Bonding)] The resin film to be measured obtained in the Examples and Comparative Examples was bonded to the resin film to be bonded, and the bonding strength was determined. Specifically, the resin film obtained in the Examples and Comparative Examples and the resin film to be bonded were each cut to 25 mm x 100 mm to form the first and second strip-shaped films 80 and 81 as shown in Figure 11. Here, the first strip-shaped film 80 was obtained by cutting the resin film obtained in the Examples and Comparative Examples, and the second strip-shaped film 81 was obtained by cutting the film to be bonded. The first and second strip-shaped films 80 and 81 were laminated with interleaving paper 83 and 84 sandwiched between each of their longitudinal ends to obtain a laminated sample 85. In this case, the first and second strip-shaped films 80 and 81 had 40 mm of interleaving paper 83 and 84 sandwiched in the longitudinal direction at both ends, and no interleaving paper was provided in the central portion 86 with a length of 20 mm. Furthermore, the first strip-shaped film 80 was positioned so that its first surface was joined to the second strip-shaped film 81. The resulting laminated sample 85 was placed on a table with the first strip-shaped film 80 facing upwards, and a 2 kg roller 87 was moved back and forth twice in the longitudinal direction from above the first strip-shaped film 80, pressing the first strip-shaped film 80 in the central portion 86, bringing it into contact with the second strip-shaped film 81, and joining the first surface of the first strip-shaped film 80 to the surface of the second strip-shaped film 81. After joining, both ends of the first strip-shaped film 80 were peeled from the interleaving papers 83 and 84, and the strip-shaped film 80 was bent while bringing the ends closer together and overlapping them, and then gripped into one of the chucks of a tensile testing machine described later. Similarly, both ends of the second strip-shaped film 81 were peeled from the interleaving papers 83 and 84, and the strip-shaped film 81 was bent while bringing the ends closer together and overlapping them, and the test piece was gripped by the other chuck of the tensile testing machine described later, and the test piece was attached to the tensile testing machine. At this time, the central portion 86, which is the joint portion of films 80 and 81, was located in the center between the chucks. Thereafter, the joint strength of the central portion 86 of the first strip-shaped film 80 and the second strip-shaped film 81 was measured within 10 minutes.The bonding strength was measured by pulling the test specimen at a tensile testing machine (Instron's "Model 5965 Universal Tester") at a speed of 50 mm / min with an initial chuck distance of 50 mm, and measuring the maximum tensile strength. The above tests were conducted under conditions of 23°C and 50% RH. The resin films used for bonding were the same resin film as the one measured, PET film (Toray Industries, Ltd., Lumirror S10, 50 μm thickness), and PEN film (Toyobo Co., Ltd., Theonex Q5100, 50 μm thickness), as shown in Table 1.

[0142] [Bonding strength after ultrasonic bonding] In the laminated sample 85, the first surface of the first strip-shaped film 80 was bonded to the surface of the second strip-shaped film 81. Then, ultrasonic bonding was performed using an ultrasonic bonding machine under the following conditions, and the bonding strength was measured in the same manner as above, except that the bonding strength was measured after the ultrasonic bonding was performed. This was defined as the bonding strength after ultrasonic bonding.

[0143] (Ultrasonic Bonding Machine Conditions) An ultrasonic hand welder "HW-D250H-28" and a simple press unit "W2005-28-Press Unit" were used, with an air pressure of 0.16 MPa, oscillation at 100%, and the bonding energy J specified by the oscillation control mode: energy. The oscillation timing was fixed at 0.5 seconds and the cooling time at 3.0 seconds. The bonding energy was set to 60 J if the resin films to be bonded were the same resin film, 120 J if they were PET films, and 120 J if they were PEN films. In ultrasonic bonding, the horn was brought into contact with the upper surface (second surface) of the first strip-shaped film 80, and the anvil was brought into contact with the lower surface of the second strip-shaped film 81. The contact surface of the horn with the second surface had numerous fine protrusions arranged at equal intervals vertically and horizontally, with a surface roughness (Rzjis) of 80 μm, and the shape of the horn bonding surface was a circle with a diameter of φ15 mm. Furthermore, when ultrasonic bonding was performed, bonding marks were formed on the upper surface (second surface) of the first strip-shaped film 80 in each example and comparative example. In Examples 1 to 4, the surface roughness (Sz) of the film surface with bonding marks was measured and is shown in Table 1.

[0144] (Position Adjustment Evaluation) Based on the bonding strength measured in each example and comparative example, the following evaluations were performed. Note that the position adjustment evaluation was based on the bonding strength when ultrasonic bonding was not performed. A: Bonding strength less than 3.5 N B: Bonding strength 3.5 N or more and less than 7 N C: Bonding strength 7 N or more

[0145] (Transportation displacement evaluation) Based on the bonding strength measured in each example and comparative example, the following evaluations were performed. Note that the transport displacement evaluation was performed based on the bonding strength before and after ultrasonic bonding. A: 0.25 N or more B: 0.1 N or more and less than 0.25 N C: Less than 0.1 N

[0146] The release substrates used in the examples and comparative examples were as follows: ・Release substrate (1): PET (polyethylene terephthalate) film, manufactured by Toray Industries, Inc., product name "Lumirror", thickness 75 μm, grade: S10, no embossing. ・Release substrate (2): Release substrate (1) with a textured surface created by random embossing. ・Release substrate (3): Release substrate (1) with a textured surface created by random embossing, with an arithmetic mean roughness approximately four times rougher than that of release substrate (2). ・Release substrate (4): Release substrate (1) with a textured surface created by random embossing, with an arithmetic mean roughness approximately eight times rougher than that of release substrate (2).

[0147] (Example 1) A resin film with separators was manufactured using the manufacturing apparatus 10 shown in Figure 5. Specifically, 100 parts by mass of thermoplastic resin (polyvinyl butyral resin, hydroxyl group content 30.3 mol%, degree of acetalization 68.5 mol%, degree of acetylation 1.2 mol%, average degree of polymerization of the raw material PVA 1700) and 35 parts by mass of plasticizer (triethylene glycol-di-2-ethylhexanoate: 3GO) were supplied to an extruder 11 and melt-kneaded to produce a resin composition, which was then extruded from a mold 12 at 205°C. Meanwhile, the first and second release substrates 21 and 22 were fed out from the first and second feeding mechanisms 31 and 32. In Example 1, the release substrate (2) was used as the first release substrate 21, and the release substrate (2) was used as the second release substrate. An extruded resin composition (resin layer 20) was sandwiched between a pair of rolls 35 and 36 heated to 80°C and 40°C respectively, between a first release substrate 21 and a second release substrate 22 to produce a laminated sheet with a resin layer 20 thickness of 200 μm. After lamination, the laminated sheet was transported using guide rolls at room temperature, and then slowly cooled in an air-cooling tank until it reached room temperature. The temperature of the laminated sheet immediately before entering the air-cooling tank was 56°C. After slow cooling, the first release substrate 21 and the second release substrate 22 were peeled off to produce the resin film of Example 1. In the resin film of Example 1, a specific uneven structure was formed on the first surface by the first release substrate 21.

[0148] (Examples 2-4, Comparative Examples 1-4) The same procedure as in Example 1 was followed, except that the type of the first release substrate and the thickness of the resin layer (resin film) were changed as shown in Table 1.

[0149]

[0150] In each of the above embodiments, when the load area ratio Smr(C) was 7% or more and 37% or less, position adjustment was easy even after overlapping another resin sheet onto the resin film, resulting in good position adjustment performance, while the bonding strength did not become too low, making it less prone to misalignment during transport. In contrast, in Comparative Examples 1 and 2, the load area ratio Smr(C) was too high, causing the resin film to bond to the other resin sheet with high bonding strength, resulting in poor position adjustment performance. Also, in Comparative Examples 3 and 4, the load area ratio Smr(C) was too low, resulting in low bonding strength and making it prone to misalignment during transport.

[0151] 10 Manufacturing equipment 11 Extruder 12 Mold 13 Feed mechanism 14 Substrate heating mechanism 15 Laminating mechanism 16 Annealing section 17 Cooling mechanism 18 Winding mechanism 20 Resin layer (resin film) 21 First release substrate 22 Second release substrate 25, 25X Laminate 31 First feed mechanism 32 Second feed mechanism 35 First roll 36 Second roll 41 Pinch roll 42, 43 Guide roll 50 Resin film 50A First surface 50B Second surface 50X First resin film 51 Protrusion 55 Another resin sheet 55X Second resin sheet 55Y Third resin sheet 58 Fifth resin film 60 Resin film with separator 61 First glass member 62 Second glass member 65 Laminate 70 Laminated glass S Load curve

Claims

1. A resin film having a first surface and a second surface, wherein at least the first surface has an uneven structure, and the uneven structure of the first surface satisfies the requirements of the following formula (1), with a load area ratio Smr(C) at C being 7% or more and 37% or less. C = Sdc(0.2%) - Spk - (Sk / 5) - 0.5 [μm] (1) (Note that in formula (1), Sdc(0.2%) is the level height at a load area ratio of 0.2%, Spk is the height of the protruding peak, and Sk is the height of the core. Smr(C) is the load area ratio (%) when the level height is C.) 2. The resin film according to claim 1, wherein the uneven structure has a random shape.

3. The resin film according to claim 1 or 2, wherein the Spk of the uneven structure on the first surface is 0.4 μm or more and 7 μm or less.

4. The resin film according to claim 1 or 2, wherein the Sk of the uneven structure on the first surface is 1.0 μm or more and 10 μm or less.

5. The resin film according to claim 1 or 2, comprising the first surface which is temporarily bonded to an adherend by ultrasonic bonding.

6. The resin film according to claim 1 or 2, wherein the load area ratio Smr(C) is 7% or more and 12% or less, and the first surface is temporarily bonded to the adherend by ultrasonic bonding.

7. The resin film according to claim 1 or 2, wherein the thickness of the resin film is 50 μm or more and 1 mm or less.

8. The resin film according to claim 1 or 2, wherein the resin film contains a thermoplastic resin.

9. The resin film according to claim 8, wherein the thermoplastic resin is at least one selected from the group consisting of polyvinyl acetal resin, ethylene-vinyl acetate copolymer resin, polyurethane resin, and ionomer resin.

10. A resin film with a separator, comprising a resin film according to claim 1 or 2, and a release substrate provided on at least one of the first and second surfaces of the resin film.

11. The resin film with separator according to claim 10, wherein the releaseable substrate is provided on the first surface, and the surface of the releaseable substrate that is in contact with the first surface has an uneven shape.

12. The resin film with separator according to claim 10, wherein the release substrate is at least one selected from the group consisting of a release film comprising a film substrate, release paper, mesh material, metal, and prepreg, and the resin constituting the film substrate is at least one selected from the group consisting of polyester resin, polyolefin resin, polyimide resin, fluororesin, silicone resin, liquid crystal polymer, polysulfone resin, cellulose acetate, polyamide resin, polyetheretherketone resin, polyetherketoneketone resin, modified polyphenylene ether, polyphenylene sulfide resin, polycarbonate resin, and polybenzimidazole resin.

13. A laminate comprising a resin film according to claim 1 or 2 and at least one other resin sheet disposed on the first surface of the resin film.

14. The laminate according to claim 13, wherein the resin constituting the other resin sheet is at least one selected from the group consisting of polyvinyl acetal resin, polyester resin, acetylcellulose resin, polyolefin resin, and polycarbonate resin.

15. The laminate according to claim 13, wherein the other resin sheet includes second and third resin sheets, both of which are arranged on the first surface.

16. The laminate according to claim 15, wherein the resin constituting the second resin sheet is at least one selected from the group consisting of polyester resin, polyolefin resin and polycarbonate resin, and the resin constituting the third resin sheet is at least one selected from the group consisting of polyvinyl acetal resin, ethylene-vinyl acetate copolymer resin, urethane resin and ionomer resin.

17. The laminate according to claim 13, wherein the second surface of the resin film having the uneven structure on the first surface has a bonding mark, and the surface roughness (Sz) at the bonding mark is 1 μm or more and 120 μm or less.

18. The laminate according to claim 13, wherein the other resin sheet is a second resin sheet having any of a dimming element, a light-emitting element, a polarizing film, a hologram film, and a power supply unit.

19. A light-emitting device comprising the laminate described in claim 13, wherein the laminate has a light-emitting element.

20. Laminated glass comprising the laminate described in claim 13 and a glass member.

21. A method for manufacturing a laminate, comprising the step of overlapping another resin sheet onto the first surface of the resin film according to claim 1 or 2 so as to be in contact with the first surface.

22. The method for manufacturing a laminate according to claim 21, further comprising the step of temporarily joining the resin film and the other resin sheet by ultrasonic bonding.

23. The method for manufacturing a laminate according to claim 22, wherein the surface roughness (Rzjis) of the horn or anvil that contacts the resin film among the horn or anvil used in ultrasonic bonding is 5 μm or more and 100 μm or less.

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