Films for resin films, laminates, circuits, sensors, displays, electronic devices, and automotive parts, building materials, electrical and electronic component manufacturing processes, and methods for manufacturing the same.

Abstract

This invention provides a resin film with high elasticity, excellent composite processability, biocompatibility, and low elution properties. [Solution] A resin film comprising a segment of chemical formula 1, wherein the average value L(%) of the elongation at break in one direction and in a direction perpendicular thereto at 23°C and 60%RH is 100% or more, and the resin film contains particles with a median diameter of 1.0 μm or more and 15 μm or less.

Description

[Technical Field]

[0001] This invention relates to a resin film that is excellent in terms of elasticity, composite processability, biocompatibility, and low elution. [Background technology]

[0002] With the development of the IoT (Internet of Things) society, the development of flexible electronics that combine high flexibility and stretchability is progressing. Flexible electronics are used in smartphones, wearable devices, security tags, automotive sensors, biosensors, strain gauges in civil engineering buildings, and circuits, sensors, and switches for precision robots. Furthermore, in recent years, their application to building components such as switches and monitors used in smart homes and functional window components has also progressed.

[0003] While flexible polyimide films are commonly used as substrates for small devices equipped with sensors and other components, they are known to have poor elasticity and recovery properties despite their good flexibility. Therefore, resin films made of olefin elastomers, urethane elastomers, and acrylic urethanes are used as materials that exhibit high elasticity (Patent Documents 1-5).

[0004] Furthermore, with the recent advancements in IoT and AI technologies, there is a growing demand for increased efficiency in the manufacturing processes of electrical and electronic components, and the application of highly flexible PVC and elastomers as process films is being considered (Patent Documents 6 and 7). [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2023-137452 [Patent Document 2] Japanese Patent Publication No. 2019-099787 [Patent Document 3] Japanese Patent Publication No. 2020-204008 [Patent Document 4] International Publication No. 2020 / 39892 [Patent Document 5] Japanese Patent Publication No. 2019-81830 [Patent Document 6] Japanese Patent Publication No. 2017-157810 [Patent Document 7] Japanese Patent Publication No. 2025-19411 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] However, the films described in these technologies are inherently soft, making it difficult for them to exhibit uniform stretching behavior, as they tend to stretch in areas that are more prone to stretching. Furthermore, PVC and thermoplastic elastomers contain many additives such as plasticizers and stabilizers, raising concerns that these additives may leach out during actual use, potentially threatening biosafety or contaminating the manufacturing process. The objective of the present invention is to solve the above-mentioned problems. Specifically, the objective of the present invention is to provide a resin film that has a structure derived from acrylic functional groups while exhibiting excellent uniform stretching behavior characteristics. [Means for solving the problem]

[0007] A preferred embodiment of the resin film of the present invention has the following features in order to solve the above problems.

[0008] (1) A resin film comprising a segment of chemical formula 1, wherein the average value L(%) of the elongation at break in one direction and in a direction perpendicular thereto at 23°C and 60%RH is 100% or more, and the resin film contains particles with a median diameter of 1.0 μm or more and 15 μm or less.

[0009] [ka]

[0010] R 1 This refers to a hydrogen or methyl group. R 2 comprises any of the following: An alkylene group and / or an arylene group having an amide group and an ether group or an ester group therein An unsubstituted alkylene group and / or an arylene group having an amide group and an ether group or an ester group therein

[0011] (2) A resin film containing the segment of Chemical Formula 1, wherein the strain showing the proportional limit in the stress-strain curve in the tensile test at 23°C and 60% RH of the resin film is 20% or more.

[0012] [Chemical formula]

[0013] R 1 refers to hydrogen or a methyl group. R 2 comprises any of the following: An alkylene group and / or an arylene group having an amide group and an ether group or an ester group therein An unsubstituted alkylene group and / or an arylene group having an amide group and an ether group or an ester group therein

[0014] (3) The resin film according to (1), wherein for the particle diameter (D50) at 50% and the particle diameter (D90) at 90% of the cumulative distribution of the particles, the ratio D90 / D50, which is the ratio of D90 to D50, is 1 or more and 3 or less. (4) The resin film according to any one of (1) to (3), wherein the weight loss rate after immersing the film in methanol at 50°C for 10 h is 5% or less. (5) The resin film according to any one of (1) to (4), wherein the content of the particles is 5% by mass or more and less than 50% by mass. (6) The resin film according to any one of (1), (3), and (5), wherein the particles are made of an inorganic substance. (7) A resin film according to any one of (1) to (6), which is a cured product obtained by crosslinking a resin precursor made of urethane acrylate. (8) A resin film according to any of (1), (3) to (7), wherein the strain showing the proportional limit in the stress-strain curve in a tensile test at 23°C and 60%RH is 20% or more. (9) A laminate comprising a resin film described in any of (1) to (8), with a release film having a release layer disposed on at least one surface of the resin film. (10) A laminate having a sheet made of fibers on at least one side of the resin film described in any of (1) to (8). (11) A circuit containing a resin film as described in any of (1) to (8). (12) A sensor containing a resin film as described in any of (1) to (8). (13) A display containing a resin film as described in any of (1) to (8). (14) An electronic device containing a resin film as described in any of (1) to (8). Automotive parts containing a resin film as described in any of (15)(1) to (8). (16) Building components containing a resin film as described in any of (1) to (8). (17) A film for electrical and electronic component manufacturing processes, comprising a resin film as described in any of (1) to (8). (18) A method for manufacturing electrical and electronic components using a resin film described in any of (1) to (8) as a process film. [Effects of the Invention]

[0015] The present invention provides a resin film that has a structure derived from acrylic functional groups, yet exhibits excellent uniform elongation behavior and composite processability, as well as superior biocompatibility and low elution. This makes it suitable for use as a base material or coating material for circuits, sensors, and switches used in automobiles, energy, electrical and electronic equipment, healthcare, wellness, infrastructure, building materials, and industrial applications. Furthermore, due to its high flexibility, resilience, and low elution properties, it can be suitably used as a base material for adhesive tapes requiring resilience, shock-absorbing materials for displays, medical film base materials, automotive surface protection film base materials, pressure sensor core materials, printed circuit boards, semiconductors, and films for the manufacturing processes of electrical components such as displays, sensors, and ICs. It can be used as a surface material, internal material, constituent material, or manufacturing process material in these applications. [Modes for carrying out the invention]

[0016] A preferred embodiment of the resin film of the present invention includes a segment of chemical formula 1, where the segment of chemical formula 1 is R 2 This refers to a (meth)acrylic residue obtained by crosslinking a (meth)acrylic group having an amide group and an ether group or an ester group inside. The above structure contains a urethane bond, and therefore contains an amide group and an ester group. The resin film of the present invention can exhibit excellent elasticity due to having this (meth)acrylic residue.

[0017] [ka]

[0018] R 1 This refers to a hydrogen or methyl group. R 2 This includes any of the following: Alkylene and / or arylene groups having an amide group and an ether or ester group inside Unsubstituted alkylene and / or arylene groups having an amide group and an ether or ester group inside.

[0019] The resin film of the present invention is preferably a cured product obtained by crosslinking a resin precursor containing specific segments described later. More specifically, it is preferably a cured product obtained by crosslinking a resin precursor containing a polydiene-based segment, and more specifically, it is preferably a cured product obtained by crosslinking a resin precursor containing at least one segment selected from the group consisting of segments of chemical formula 2, segments of chemical formula 3, segments of chemical formula 4, and hydrogenated versions thereof.

[0020] [ka]

[0021] [ka]

[0022] [ka]

[0023] Chemical formulas 2 and 3 have cis and trans isomers, and either can be used. A mixture of the cis and trans forms may also be used. Furthermore, it is preferable that the alkylene group having an ether or ester group contains a polydiene segment, or that the unsubstituted alkylene group having an ether or ester group contains a polydiene segment.

[0024] In this embodiment, the resin film can exhibit low polarity and high flexibility. This makes it possible to achieve both stability and flexibility in relation to solvents.

[0025] Examples of methacrylate compounds in the present invention include, but are not limited to, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl methacrylate, polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, dipentaerythritol mono(meth)acrylate, dipentaerythritol di(meth)acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexa(meth)acrylate.

[0026] Examples of diisocyanate compounds include, but are not limited to, 4,4'-methylenebis(cyclohexyl isocyanate), methylcyclohexane-2,4 (or 2,6)-diisocyanate, isophorone diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, dimer acid diisocyanate, isophorone diisocyanate, 1,3-cyclohexylene diisocyanate, 4,4'-methylene-bis(cyclohexyl isocyanate), tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate, xylylene diisocyanate, dianisidine diisocyanate, phenyl diisocyanate, halogenated phenyl diisocyanate, 1,5-naphthalene diisocyanate, polymethylene polyphenylene diisocyanate, and naphthalene diisocyanate.

[0027] Furthermore, examples of polyols include, but are not limited to, polyether polyols, polymer polyols (polyols produced by copolymerizing acrylonitrile or styrene in a polyether polyol and dispersing polymer fine particles), polyolefin polyols, polyester polyols, and polycarbonate polyols. Among the above, polyolefin polyols and polycarbonate polyols are particularly preferred from the viewpoint of stability with respect to solvents.

[0028] The resin film of the present invention is preferably a cured product obtained by crosslinking a precursor made of urethane acrylate among the compounds having the aforementioned structure. Urethane acrylate is a compound obtained by urethane reaction of polyol, polyisocyanate, and hydroxyl group-containing (meth)acrylic acid ester. Since the urethane skeleton functions as a soft segment and the acrylic skeleton functions as a hard segment, high flexibility and durability can be achieved. Commercially available urethane acrylate can be used as the precursor, or the aforementioned compounds can be arbitrarily combined and polymerized for use.

[0029] In the resin film of the present invention, it is preferable to use a polymerization initiator to promote crosslinking of the resin precursor during manufacturing. Examples of polymerization initiators used in the resin film of the present invention include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isobutyl ether, α-hydroxyacetophenone, diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyldimethylketal, 1-hydroxycyclohexyl-phenyl ketone, 2-methyl-2-morpholino(4-thiomethylphenyl)propan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, and bis(2,4,6-trimethylbenzoyl)phenyl Examples of polymerization initiators include, but are not limited to, acylphosphine oxide compounds such as phosphate phosphine oxide or diphenyl-2,4,6-trimethylbenzoylphosphine oxide, benzophenone, methyl o-benzoylbenzoate, hydroxybenzophenone, 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, 2,4-tris(trichloromethyl)-S-triazine, 2-methyl-4,6-bis(trichloro)-S-triazine, 2-(4-methoxyphenyl)-4,6-bis(trichloromethyl)-S-triazine, iron-allene complexes, and titanocene compounds. These polymerization initiators may be used individually or in combination of two or more.

[0030] Among the above, it is preferable to use a polymerization initiator consisting of an acylphosphine oxide compound selected from 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, or diphenyl-2,4,6-trimethylbenzoylphosphine oxide, from the viewpoint of promoting molecular polymerization and suppressing the formation of low molecular weight products containing amide groups.

[0031] The weight-average molecular weight (Mw) of the resin precursor constituting the resin film of the present invention is preferably 10,000 or more and 100,000 or less, and more preferably 10,000 or more and 80,000 or less. Having the above characteristics makes it easier to maintain coatability when manufacturing the film by coating and to achieve both the mechanical properties described later. If the Mw of the resin precursor is less than 10,000, the molecular weight of the resin precursor is too small, which may result in a decrease in mechanical properties when it is made into a resin film. If the Mw of the resin precursor is greater than 100,000, the coatability may decrease during the manufacturing of the resin film, and the appearance and thickness controllability may decrease. The weight-average molecular weight of the resin precursor can be evaluated by GPC (gel permeation chromatography) measurement.

[0032] A preferred embodiment of the resin film of the present invention contains particles with a median diameter (particle diameter representing 50% of the cumulative distribution (D50)) of 1.0 μm or more and 15 μm or less. In a resin film containing segments of chemical formula 1, where the average value L(%) of the elongation at break in one direction and in a direction perpendicular to it at 23°C and 60% RH is 100% or more, the inclusion of median-type particles within this range allows the particles to exhibit a nodal-like effect, thereby enabling the expression of excellent mechanical properties, composite processability, and resilience. If the median diameter is larger than the above range, the surface area per particle decreases, leading to increased stress concentration at the particle / resin interface during film stretching. This makes irreversible delamination more likely to occur at this interface, potentially leading to the formation of voids during stretching and a decrease in mechanical properties and resilience, or the large-diameter particles themselves may become a drawback. When the median diameter is less than 1.0 μm, the surface area of ​​the particles increases, making them more prone to aggregation. These aggregates can become defects in the film, or, similar to when large-diameter particles are included, cause stress concentration at the particle / resin interface, leading to a decrease in resilience and mechanical properties. The median diameter of the particles contained in the film shall be analyzed using the method described later. The median diameter of the particles is more preferably between 2.0 μm and 10 μm.

[0033] The particles contained in the resin film of the present invention preferably have a ratio of D90 to D90, D90 / D50, of 1 to 3 for the particle diameters of 50% (D50) and 90% (D90) of the cumulative particle distribution, and more preferably 1 to 2. By using particles with a ratio within the above range, the inclusion of coarse particles can be suppressed, reducing defects in the film and localized stress concentration at the particle / resin interface, thereby enabling the film to exhibit excellent mechanical properties and resilience. If D90 / D50 exceeds the above range, the proportion of large-diameter particles increases, which can lead to increased stress concentration and a decrease in mechanical properties. The lower limit for the ratio of D90 to D50 of particles is 1, where the values ​​of both are equal. The D90 and D50 of particles can be measured by the methods described later. Control of D90 / D50 can be achieved by particle classification, blending, etc.

[0034] The resin film of the present invention preferably has a ratio (D50 / t) of the median diameter (D50) of the particles to the film thickness (t) of 0.15 or less, and more preferably 0.10 or less. If the median diameter ratio exceeds the above range, when the particles are blended at the concentrations described later, the particles tend to be too large, resulting in areas where the resin component concentration is significantly lower in the thickness direction, which may make the film prone to breakage when stretched. The lower limit of the median diameter ratio is preferably 0.01, based on the relationship between the preferred median diameter of the particles and the film thickness.

[0035] The concentration of particles in the resin film of the present invention is preferably 5% by mass or more and 50% by mass or less, and more preferably 10% by mass or more and 50% by mass or less. By including a concentration within the above range, the concentration of resin components in the film can be reduced, thereby reducing leaching from the resin components and obtaining a film with excellent biosafety. In addition, the presence of particles in the resin creates interaction between particles and resin, resulting in the effect of uniformly transmitting stress to the molecular chains of the resin compared to when only resin is used. This allows for control of mechanical properties and resilience when it is made into a resin film. Furthermore, the particles contained in the film have a spacer function during press processing, and in processes where pressure is applied during composite processing, crushing in the thickness direction can be suppressed, improving composite processability. If the particle concentration falls below the above range, the effect of reducing leaching may be low, or it may be difficult to control mechanical properties or achieve composite processability. If it exceeds the above range, the concentration of resin components in the film may be too low, resulting in reduced elongation, or the interparticle distance may become too high, causing particle aggregation and a decrease in quality. The concentration of particles contained in the resin film can be analyzed by the method described later.

[0036] The particles contained in the resin film of the present invention may be either organic or inorganic particles, but inorganic particles are preferred from the viewpoint of chemical stability and durability. Examples of particles contained in the resin film include, but are not limited to, organic particles such as particles composed of acrylic resins, styrene resins, silicone resins, polyimide resins, and olefin resins, and inorganic particles such as oxide ceramics such as alumina, silica, titania, zirconia, magnesia, ceria, yttria, zinc oxide, and iron oxide, nitride ceramics such as silicon nitride, titanium nitride, and boron nitride, silicon carbide, calcium carbonate, aluminum sulfate, barium sulfate, potassium titanate, talc, kaolin clay, kaolinite, halloysite, pyrophyllite, montmorillonite, sericite, mica, amethyst, bentonite, asbestos, zeolite, calcium silicate, magnesium silicate, diatomaceous earth, silica sand, glass fibers, and glass beads. Furthermore, one type of these particles may be used alone, or two or more types may be used in mixture.

[0037] The specific gravity of the particles contained in the resin film of the present invention is preferably 0.1 to 4.5, due to the ease of adjusting the blending ratio. The specific gravity of the particles contained in the resin film can be evaluated by the method described later.

[0038] The resin film of the present invention preferably has a weight loss rate of 5% or less, more preferably 3% or less, and even more preferably 2% or less after immersion in methanol at 50°C for 10 hours. The weight loss rate depends on the amount of impurities such as polymer polymerization residues and low molecular weight additives contained in the film. Some of these substances may have adverse effects if they continue to come into contact with the skin, etc., or may bleed out onto the film surface and contaminate it. By having the above characteristics, when the film is used in applications where it comes into contact with the human body, the impact on the human body can be suppressed and biosafety can be ensured. In addition, by suppressing components that are prone to bleeding out during practical use of the film, the decrease in adhesion when the film is composited with other materials can be suppressed. If the weight loss rate exceeds the above range, the amount of impurities that precipitate on the film surface during practical use will increase, which may cause rashes or inflammation in applications where the film comes into contact with the skin, or a decrease in adhesion when the film is composited. The preferred lower limit of the weight loss rate is 0%, where no components are leached out at all. The weight loss rate can be achieved by blending particles into the film or by using a resin with the above-mentioned characteristics. The weight loss rate can also be measured by the method described later.

[0039] The resin film of the present invention preferably has an average value L(%) of elongation at break in one direction and in a direction perpendicular to it at 23°C and 60% RH of 100% or more, more preferably 150% or more, even more preferably 250% or more, and particularly preferably 300%. By setting the average value L of elongation at break within the above range, the flexibility of the resin film can be increased. If the average value L of elongation at break is less than 100%, the resin film may lack flexibility when put into practical use, which may lead to device damage. The upper limit of the average value L of elongation at break is preferable as much as possible, but the physically achievable range is 800% or less. The value of elongation at break can be achieved by using a resin with the molecular weight described above.

[0040] The resin film of the present invention preferably has an average value E (MPa) of the elastic modulus in one direction and the direction perpendicular to it at 23°C and 60% RH of 100 MPa or less, more preferably 50 MPa or less, and even more preferably 10 MPa or less. Having the above characteristics allows for excellent flexibility and resilience in practical use. If the elastic modulus exceeds 100 MPa, the stiffness of the film will result in insufficient flexibility when used in practical applications such as stretchable circuits, sensors, switches, etc., making it difficult to conform to the complex shapes of objects to which the circuits, sensors, switches, etc. are attached. The lower limit of the elastic modulus is preferably as low as possible, and theoretically it is 0 MPa. The elongation at break and elastic modulus can be evaluated by the method described later.

[0041] A preferred embodiment of the resin film of the present invention is that the strain exhibiting the proportional limit in the stress-strain curve during a tensile test at 23°C and 60%RH is 20% or more, more preferably 30% or more. The proportional limit refers to the point in the stress-strain curve during a tensile test of a film where, initially, stress and strain maintain a directly proportional relationship, but as the strain increases, this relationship gradually becomes unproportional. Generally, highly flexible films have a small strain exhibiting this proportional limit, making it difficult to achieve both high strength and elongation as a film, and they are known to exhibit non-uniform elongation behavior in practical use. The resin film of the present invention can control this strain exhibiting the proportional limit, and when the film is put into practical use, it exhibits uniform elongation behavior and excellent resilience. If the strain exhibiting the proportional limit falls below the above range, when the film is used in applications where it is stretched, stress propagation due to stretching becomes difficult, resulting in partial deformation, thickness deviation during stretching, breakage, or reduced resilience. The upper limit of the strain exhibiting the proportional limit is 800%, which is the upper limit of the elongation at break of the resin film. The strain exhibiting the proportional limit can be controlled by using the aforementioned formula. The strain exhibiting the proportional limit will be calculated using the method described later.

[0042] The resin film of the present invention is not limited in the number of layers, as long as it forms a film-like structure on its own; it may be formed from one layer or from two or more layers. Here, a layer refers to a portion that has a boundary surface that can be distinguished from adjacent portions in the thickness direction and has a finite thickness. More specifically, it refers to a portion that can be distinguished by the presence or absence of discontinuous boundaries when the cross-section of the resin film is observed with an electron microscope (transmission type, scanning type) or an optical microscope. Even if the composition of the resin film changes in the thickness direction, if there are no boundaries between them as described above, it is treated as a single layer.

[0043] The thickness of the resin film of the present invention is not particularly limited and can be appropriately selected depending on the application. The lower limit of the thickness of the resin film cannot be determined in general terms, as it is affected by the elastic modulus of the resin film itself, the elongation at break, the peel force from the laminate, and the peel angle. However, when achieving physical properties equivalent to those of a general flexible material using the laminate manufacturing method described later, it is preferable that the thickness be 10 μm or more.

[0044] The resin film of the present invention can have a support substrate laminated on one side thereof. As the support substrate, a film made of either a thermoplastic resin or a thermosetting resin can be used. As the support substrate, a film made of polyolefin resins such as polyethylene, polypropylene, polystyrene, and polymethylpentene; alicyclic polyolefin resins; polyamide resins such as nylon 6 and nylon 66; aramid resins; polyimide resins; polyester resins; polycarbonate resins; polyarylate resins; polyacetal resins; polyphenylene sulfide resins; fluororesins such as tetrafluoroethylene resin, trifluoroethylene resin, trifluoroethylene chloride resin, tetrafluoroethylene-hexafluoropropylene copolymer, and vinylidene fluoride resin; acrylic resins; methacrylic resins; polyacetal resins; polyglycolic acid resins; polylactic acid resins; phenolic resins; epoxy resins; urea resins; melamine resins; unsaturated polyester resins; polyurethane resins; polyimide resins; silicone resins, etc., can be used. Among the above, polyester resin, polycarbonate resin, acrylic resin, or methacrylic resin are particularly preferred from the viewpoint of strength, heat resistance, and transparency.

[0045] The support substrate used in the present invention may be a single-layer structure or a laminated structure. Furthermore, the surface of the support substrate may be pre-applied with functional layers such as an easy-adhesion layer, an antistatic layer, an undercoat layer, an ultraviolet-absorbing layer, or a release layer.

[0046] The support substrate used in the present invention preferably has a release layer to control the peeling force between the support substrate and the resin film. The release layer may be on one side or both sides of the support substrate. The composition and thickness of the release layer are not particularly limited as long as the peeling force from the resin film can be controlled to any desired extent. Examples of support substrates provided with a release layer include "Therapyle" (registered trademark) manufactured by Toray Film Processing Co., Ltd., "Unipeel" (registered trademark) manufactured by Unitika Ltd., "Panapeel" (registered trademark) manufactured by Panac Co., Ltd., "Toyobo Ester" (registered trademark) manufactured by Toyobo Co., Ltd., and "Purex" (registered trademark) manufactured by Teijin Limited, and these products can also be used.

[0047] An example of a method for manufacturing the resin film of the present invention is described below. Preferably, the resin film of the present invention comprises the following steps: applying a coating agent containing the aforementioned segment-containing resin precursor to a support substrate to form a coating layer (step 1); then removing the solvent from the coating layer and drying it (step 2); irradiating it with active energy rays to crosslink the resin precursor (step 3); heat treating it (step 4); and peeling off the release film from the laminate (step 5).

[0048] The method for applying the coating agent to the support substrate in step 1 is not particularly limited, as long as the coating agent is applied to the support substrate and a uniform coating layer is formed in the surface. The coating method on the film can be appropriately selected from methods such as dip coating, roller coating, wire bar coating, gravure coating, and die coating. Here, the coating layer refers to the "liquid layer" formed by the coating process.

[0049] The method for removing the solvent in step 2, i.e., the drying method, is not particularly limited as long as it can remove the solvent from the coating layer formed on the support substrate. Examples of drying methods include heat transfer drying (adhesion to a high-temperature object), convection heat transfer (hot air), radiant heat transfer (infrared rays), and others (microwaves, induction heating). Among these, in the resin film manufacturing method of the present invention, a method using convection heat transfer or radiant heat transfer is preferred because it is necessary to precisely uniformize the drying speed in the width direction.

[0050] The crosslinking method of Project 3 is to irradiate the coating layer from which the solvent has been removed after drying with active energy rays to cause a reaction and crosslink the coating film.

[0051] Crosslinking by active energy rays is preferably electron beam (EB) and / or ultraviolet rays (UV) from the viewpoint of versatility. Further, examples of the type of ultraviolet lamp used when irradiating ultraviolet rays include a discharge lamp method, a flash method, a laser method, an electrodeless lamp method, and the like. When ultraviolet curing is performed using a high-pressure mercury lamp which is a discharge lamp method, the illuminance of ultraviolet rays is 100 mW / cm 2 to 3,000 mW / cm 2 or less is preferable, and more preferably 200 mW / cm 2 to 2,000 mW / cm 2 or less, and ultraviolet irradiation is preferably performed under the condition that the integrated light quantity of ultraviolet rays is 100 mJ / cm 2 to 3,000 mJ / cm 2 or less, and more preferably 200 mJ / cm 2 to 2,000 mJ / cm 2 or less. Here, the ultraviolet illuminance is the irradiation intensity received per unit area, and it varies depending on the lamp output, the emission spectrum efficiency, the diameter of the emission bulb, the design of the reflector, and the light source distance from the irradiated object. However, the illuminance does not change depending on the conveyance speed. Further, the integrated light quantity of ultraviolet rays is the irradiation energy received per unit area, and it is the total amount of photons reaching the surface. The integrated light quantity is inversely proportional to the irradiation speed passing under the light source, and is proportional to the number of irradiation times and the number of lamp lights.

[0052] The method for producing the resin film of the present invention can have a step of performing heat treatment for the purpose of further reducing impurities after irradiating and crosslinking with active energy rays.

[0053] The coating agent used in manufacturing the resin film of the present invention can be obtained by mixing, stirring, and adjusting the aforementioned resin precursor and other components and solvents. The composition, viscosity, and solid content ratio are not particularly limited, as long as a resin film exhibiting the properties of the present invention can be formed.

[0054] The coating agent used in the production of the resin film of the present invention may contain a solvent from the viewpoint of coating properties and mixability. The type of solvent is not particularly limited as long as it can uniformly dissolve the resin precursor and other components and has low reactivity with the composition. Specific examples of solvents include organic solvents such as methanol, ethanol, isopropyl alcohol, propylene glycol monomethyl ether, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, butyl acetate, toluene, and xylene, as well as water. One type may be used alone, or two or more types may be used in combination.

[0055] The coating agent used in the production of the resin film of the present invention may also contain other polymerizable compounds besides the resin precursor, such as monofunctional monomers having one polymerizable unsaturated bond, and polyfunctional monomers having two or more polymerizable unsaturated bonds. Examples of monofunctional monomers include hydroxyl group-containing monofunctional (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl acrylate, and 4-hydroxybutyl acrylate, as well as acryloyl morpholine, dimethylacrylamide, and isobornyl acrylate. Examples of polyfunctional monomers include hydroxyl group-containing polyfunctional (meth)acrylates such as dipentaerythritol di, tri, tetra, or penta(meth)acrylate, pentaerythritol di or tri(meth)acrylate, DPH(M)A (dipentaerythritol hexa(meth)acrylate), pentaerythritol tetra(meth)acrylate, tripropylene glycol di(meth)acrylate, and trimethylolpropane tri(meth)acrylate. These monomers may be used individually, in combination of two or more, or in combination of monofunctional and polyfunctional monomers.

[0056] The coating agent used in the production of the resin film of the present invention may also contain, to the extent that it does not impair the properties of the resin film, a thermal polymerization inhibitor, an ultraviolet absorber, a silane coupling agent, a plasticizer, a flame retardant, an antistatic agent, an anti-aging agent, an antibacterial agent, an antifungal agent, an antifoaming agent, a leveling agent, a filler, a thickener, an adhesion promoter, a thixotropic agent, a gloss agent, and an antioxidant.

[0057] The coating agent used in the production of the resin film of the present invention may contain, as an antioxidant, hindered phenol-based, semi-hindered phenol-based radical scavengers, phosphite-based, or thioether-based peroxide decomposing agents.

[0058] The resin film of the present invention may contain an acrylic copolymer or a silicone-based or fluorine-based leveling agent as a leveling agent.

[0059] The resin film of the present invention may contain metal salts such as lithium salts, sodium salts, potassium salts, rubidium salts, cesium salts, magnesium salts, and calcium salts as antistatic agents.

[0060] The resin film of the present invention is suitable for use as a base material for various flexible electronics due to its high elasticity, excellent composite processability, and biosafety. Specifically, it can be suitably used as a base material or coating material for circuits, sensors, and switches used in automobiles, energy, electrical and electronic equipment, healthcare, wellness, infrastructure, building materials, and industrial applications. Furthermore, from the viewpoint of high flexibility and resilience, it can be suitably used as a base material for adhesive tapes requiring resilience, shock-absorbing materials for displays, medical film base materials, automotive surface protection film base materials, pressure sensor core materials, printed circuit boards, semiconductors, displays, and films for the manufacturing process of electrical and electronic components such as sensors and ICs.

[0061] The resin film of the present invention can also have an electrical circuit formed on at least one surface. There are no particular limitations on the method of forming the electrical circuit; general methods for forming FPCs (flexible printed circuit boards), or printing methods such as inkjet printing, flexographic printing, screen printing, gravure printing, and offset printing can be used.

[0062] The resin film of the present invention is preferably classified as either category 0 to 2, and more preferably as category 0 or 1, in the peel strength evaluation by the cross-cut method described in JIS K5600-5-6 (1999) for evaluation of composite processability. Having the above characteristics allows for use without peeling when composited with other materials, and enables the development of excellent properties. The above characteristics can be achieved by manufacturing using the composition and method described above. The above characteristics can be evaluated using the method described later.

[0063] The resin film of the present invention preferably has a residual deformation rate in the thickness direction after pressing of 5% or less, and preferably less than 3%, as an evaluation of its composite processability. Having the above characteristics minimizes deformation during heat pressing or other processes when the resin film is used as a base material or coating for circuits, sensors, switches, or as a film for the manufacturing process of electrical and electronic components, enabling dimensional control after processing. If the residual deformation rate after pressing exceeds 5%, the thickness of the resin film may decrease during composite processing when the parts are assembled into modules, potentially causing gaps or other problems, or reducing mechanical strength. The lower limit of the residual deformation rate should be as small as possible, preferably 0% or more. The residual deformation rate in the thickness direction after pressing can be achieved using the formulation described above. Furthermore, the residual deformation rate can be measured using the method described later.

[0064] The resin film of the present invention preferably has a recovery rate of 90% or more, and more preferably 95% or more, after being stretched and held at 50% in any one direction of the film and in a direction perpendicular thereto. Having the above characteristics allows for repeated use when used in practical applications such as stretchable circuits, sensors, switches, and building components. If the recovery rate is less than 90%, distortion may remain when stretched and contracted in practical applications, leading to a decrease in flatness or a decrease in performance as a circuit, sensor, switch, or building component. The upper limit of the preferred range for recovery rate is 100% or less. Recovery rate can be achieved by using the formulation described above. Recovery rate can be evaluated by the method described later.

[0065] The resin film of the present invention preferably has a deformation rate due to necking of less than 70% when stretched to 100%, and more preferably less than 50%. Necking refers to the phenomenon in which a film is stretched and deformed partially rather than uniformly as a whole when stretched in a solid state. In resin films with a low modulus of elasticity and weak intermolecular forces, stress during stretching tends to concentrate on some molecular chains, leading to increased necking. However, after diligent research, the film of the present invention has succeeded in achieving both a low modulus of elasticity and suppression of necking. If the deformation rate due to necking exceeds 70%, the deformation may be large and the practicality may decrease when the film is processed and used alone or combined with other materials. The lower limit of the deformation rate due to necking is preferable as much as possible, and preferably 0% or more. The deformation rate due to necking can be evaluated by the method described later. The deformation rate due to necking can be achieved by using the formulation described above.

[0066] The resin film of the present invention preferably receives a score of either A or B, more preferably A, when evaluated for biocompatibility (skin irritation) according to Draize's criteria using the method described later. Having the above characteristics allows for safe use in applications where skin contact is anticipated. These characteristics can be achieved by manufacturing using the composition and method described above. These characteristics can be evaluated using the method described later.

[0067] The resin film of the present invention preferably has fewer than 30 defects visible per 150 mm x 150 mm area, and more preferably fewer than 10 defects. Having the above defect count allows for both excellent mechanical properties and high quality. The lower limit of the defect count is 0 or more. The above characteristics can be achieved by using the composition described above. The above characteristics can be evaluated using the method described later.

[0068] The resin film of the present invention can also be formed into a laminate by laminating a sheet made of fibers to at least one surface of the resin film. By laminating the fiber sheet, the strength and durability of the resin film can be enhanced when it is put into practical use. Woven fabrics, knitted fabrics, and nonwoven fabrics can be suitably used as the fiber sheet for the laminate of the present invention.

[0069] The method for joining the laminate of resin film and fiber sheets according to the present invention is not particularly limited, but a known lamination method can be employed. For example, methods using acrylic, urethane, or epoxy adhesives, or methods that directly join the fiber sheet and resin film, such as compression methods (compression techniques using rolls or presses), can be used.

[0070] The resin film of the present invention is preferably such that, when evaluated for the presence or absence of film component elution during pressing using a SUS plate as described later, the film can be peeled off without remaining on the SUS plate, and the mirror-side surface of the SUS plate is free from clouding. Having these characteristics, the resin film can be suitably used in processes for processing devices as a base material or coating material for circuits, sensors, and switches, or as a film for the manufacturing process of electrical and electronic components, without contaminating the process. These characteristics can be achieved by using the composition described above. These characteristics can be evaluated using the method described later. [Examples]

[0071] Next, the present invention will be described based on examples, but the present invention is not necessarily limited to these examples.

[0072] (1) Characteristics of particles contained in the film a.Particle type The film was cut into 5mm x 10mm sections from any point, and these were placed in an automated rotary microtome with a freezing device (RM2265 / LN22, Leica) to produce 100μm thick ultrathin sections at -100°C. These ultrathin sections were placed on a diamond compression cell, and measurements were taken by transmission using a micro-IR microscope (Spotlight200, Perkin Elmer) with a 50μm x 50μm aperture. A total of 300μm x 300μm of imaging IR was collected, and the composition of the particle portion observed in the ultrathin sections was analyzed. For identification, the analysis software Spectrum (PerkinElmer) was used to perform single-component and composite-component searches in the spectral library to identify the resin composition. The spectral libraries used are as follows.

[0073] <Spectral Library> PKJ Library • IChem / Aldrich ATR Standard • IChem / Aldrich ATR polymers, polymer additives • IChem / Aldrich ATR coating • IChem / Aldrich paints • IChem SDBS Standard Complete Collection IChem SDBS polymer, polymer additive.

[0074] b. Particle concentration A sample was cut from an arbitrary section, placed in a weighed crucible, and weighed again. The sample was then heated in a muffle furnace (manufactured by Yamato Scientific Co., Ltd.) at 500°C for 6 hours to incinerate it. After the crucible cooled, it was weighed again, and the weight after heating was measured. The weights before and after heating were plugged into the following formula to calculate the particle content in the film. The amount of sample used was adjusted so that the mass of the remaining material was in the range of 100-200 mg. Particle content (mass %) = Weight after heating (mg) / Weight before heating (mg) × 100.

[0075] c. Particle size (median diameter, D50, D90) The ash obtained in b. was mixed with purified water to prepare a dispersion with a transmittance of approximately 90%. This dispersion was then measured using a laser diffraction scattering particle size distribution analyzer (Microtrac MT3000, manufactured by Microtrac Bell Co., Ltd.) under the conditions of a laser wavelength of 780 nm and a measurement temperature of 25°C. After ultrasonic treatment for 4 minutes before measurement, the dispersion was measured in accordance with JIS Z8825-1:2001. From the particle size distribution of the sample, the particle sizes (D10, D50, D90) of the 10%, 50%, and 90% values ​​of the cumulative distribution were determined.

[0076] d.Specific gravity The specific gravity of the particles contained in the resin film was measured using the ash content obtained in b., according to the specific gravity measurement method using a specific gravity bottle described in JIS Z8807 (2012).

[0077] (2) Percentage of film weight reduction before and after methanol extraction A sample was prepared by cutting a piece of resin film from a desired location to a size of approximately 1 g, and peeling off the support substrate. The weight x (g) of the cut sample was weighed and placed in a 50 mL screw-top bottle. 15 g of methanol (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., special grade, purity >99.8%) was added, the sample was submerged in the liquid, a stirring bar was inserted, and the bottle was sealed with lab film. This was then subjected to an extraction procedure on a hot stirrer (manufactured by AS ONE Corporation, LSH-4D) at a top plate temperature of 50°C with stirring at 100 rpm for 10 hours. After 10 hours, the sample was removed from the methanol and dried at room temperature for 48 hours, after which the weight y (g) of the sample was measured. The weight of the sample before and after extraction was applied to the following formula to measure the percentage reduction in film weight (%) before and after methanol extraction. Film weight reduction rate (%) = {(xy) / x} × 100.

[0078] (3) Identification of segments and resin types contained in the resin film After peeling the support substrate from the surface of the resin film, FT-IR (Fourier Transform Infrared Spectroscopy) (PerkinElmer, Frontier GOLD) was used to perform ATR (single-pass reflection measurement) with 128 integrations and a resolution of 4 cm. -1 Infrared spectroscopy spectra were collected, and various segments contained in the resin film were identified based on the detected functional group information. For the measurement, the ATR crystal was soaked in 0.5 ml of alcohol on a "Kimwipe" (registered trademark) (manufactured by Nippon Paper Crecia, S-200), rubbed more than five times to clean it, and then wiped again more than five times with a "Kimwipe" (registered trademark) that did not contain alcohol to clean the crystal before the measurement was performed. Furthermore, when sampling, wear new nitrile gloves (manufactured by TRUSCO Nakayama Co., Ltd., TGNN10BM) on your hands to avoid direct contact with the sample. When placing the sample in the ATR, the sample should be pressed against the crystal using a holding bar while monitoring the spectral measurement, and the pressure should be maintained until no further changes occur in the spectrum. For identification, the analysis software Spectrum (manufactured by PerkinElmer) was used. After automatically correcting the measured spectrum with the same software, single-component and composite-component searches were performed by referring to the spectrum library used in (1) to identify the resin composition.

[0079] (4) Mechanical properties of resin film a. Elongation at break L (%) Before measurement, the resin film was left to stand for 24 hours in an atmosphere of 23°C and 60% RH humidity. Ten strips measuring 10 mm wide x 150 mm long were cut from either one direction of the resin film and from a direction perpendicular to it. The resin film was then peeled from the support substrate to prepare the test specimens. Using a tensile testing machine (Orientec "Tensilon" (registered trademark) UCT-100), the initial tensile chuck distance was set to 50 mm, the tensile speed to 300 mm / min, and the tensile test was performed at a measurement temperature of 23°C and 60% RH humidity to determine the elongation at break (%) for each test specimen. The average value was calculated using the following formula and defined as the elongation at break L (%) for that sample. Elongation at break L (%) = (Average value of elongation at break measured 10 times in any one direction) + (Average value of elongation at break measured 10 times in a perpendicular direction)) / 2.

[0080] b. Modulus of elasticity E (MPa) The elastic modulus of each test specimen was determined using the SS curve obtained during the measurement of the elongation at break of specimen a, according to the calculation method described in JIS K 7161-1 (2014). The average value was calculated using the following formula, and this was defined as the elastic modulus E (MPa) of the sample. The modulus of elasticity E (MPa) = (average of the modulus of elasticity measured 10 times in any one direction) + (average of the modulus of elasticity measured 10 times in orthogonal directions)) / 2.

[0081] c. Distortion showing the proportional limit The stress indicating the proportional limit is defined as the point just before the point where the sum of squared errors (SSE) between the measurement data constituting the SS curve obtained during the fracture elongation measurement of a and the calculated data constituting the approximate straight line obtained from the measurement data using the least squares method exceeds a predetermined threshold. The threshold is 1.5 × 10⁻⁶. 8 Let's assume that.

[0082]

number

[0083] y: measured stress value, f(x): stress value calculated from the approximate line. The strain representing the proportional limit stress, determined from the above, was read from the SS curve and designated as the strain representing the proportional limit.

[0084] (5) Thickness of the resin film The thickness of the resin film, after the support substrate was removed, was measured at five arbitrary points on the resin film using a high-precision thickness gauge (Nikon Corporation, DEGIMICRO MH-15M), and the average value was defined as the thickness of the resin film.

[0085] (6) Weight-average molecular weight (Mw) of the resin precursor The molecular weight of the resin precursor was determined by measuring the weight-average molecular weight (Mw) using a GPC (gel permeation chromatography) analyzer (HLC-8220, manufactured by Tosoh Corporation).

[0086] (7) Composite workability a. Adhesion with paste A resin film was fixed onto a glass plate, and a silver paste for stretchable substrates (manufactured by Asahi Chemical Research Institute Co., Ltd., LS-453-6B) was applied thereon using an applicator to achieve a coating thickness of 5 μm after drying. After drying at 80°C for 30 minutes, the surface was heated at 120°C for 10 hours. The adhesion was then evaluated according to the cross-cut method described in JIS K5600-5-6 (1999), and the results were evaluated according to the classification in JIS K5600-5-6 (1999), with the following criteria used for determination. A: Classification 0 B: Classification 1 and 2 C: One of categories 3-5.

[0087] b. Residual deformation rate of thickness after pressing A 10cm x 10cm test piece was cut from any point on the film, the support substrate was peeled off to obtain the sample, the thickness at the four corners and the center was measured, and the average value was calculated to be the thickness Tb (μm) before pressing. A 1mm thick SUS plate / PI film (100μm, "Kapton" (registered trademark), manufactured by Toray DuPont Co., Ltd.) / sample / PI film / SUS plate were stacked in that order, and the sample was heated in a 20t heating and cooling press (manufactured by Oji Machinery Co., Ltd.) heated to 180°C for 5 seconds preheating, and then heated for 5 minutes under a pressure of 4MPa. After removing the sample from the press and letting it cool, the thickness at the four corners and the center was measured again, the average value was calculated to be the thickness Ta (μm) after pressing. The obtained thickness was plugged into the following formula to calculate the residual deformation rate (%) of the thickness after pressing, and evaluated according to the following criteria. Residual deformation rate (%) = {(Tb-Ta} / Tb} × 100 A: Residual deformation rate is less than 3% B: Residual deformation rate is between 3% and 5%. C: The residual deformation rate is greater than 5%.

[0088] (8) Biosafety (skin irritation) After cutting the resin film into 1cm x 1cm pieces and peeling off the support substrate, a patch was prepared by placing it in the center of a 2.5cm x 2.5cm piece of adhesive bandage tape (Nichiban, H25). The above patch was applied to the skin on the back of a shaved rabbit and left in place for 24 hours. After that, the patch was removed from the skin, the condition of the skin was checked, and it was evaluated according to the following criteria based on Draize's evaluation criteria. <Score> A: No erythema B: Very mild erythema (barely noticeable) C: Mild erythema D: Moderate to severe erythema E: Deep red, intense erythema and mild crusting.

[0089] (9) Resilience Before measurement, the resin film was left to stand for 24 hours in an atmosphere of 23°C and 60% RH humidity. Ten strips measuring 10 mm wide x 150 mm long were cut from either one direction of the resin film and from a direction perpendicular to it. The resin film was then peeled from the support substrate to prepare the test specimens. Using a tensile testing machine (Orientec "Tensilon" (registered trademark) UCT-100), the initial test length Sb was marked at 50 mm, the tensile speed was set to 100 mm / min, and the specimen was stretched to a chuck distance of 75 mm (50% elongation) under measurement temperature of 23°C and 60% RH humidity, after which it was held for 5 minutes. After holding, the sample was returned to the initial displacement at a speed of 100 mm / min, and the sample was removed and left to stand for 15 minutes. After standing, the test length Sa (mm) after evaluation was measured. The recovery rate (%) was calculated by plugging the test lengths before and after evaluation into the following formula. Recovery rate (%) = {25 - (Sa - Sb)} / 25 × 100} The average value of all samples obtained in the evaluation was calculated and used as the recovery rate for that sample. The recovery performance was then evaluated according to the following criteria. A: Recovery rate of 95% or higher B: Recovery rate between 90% and 95% C: Recovery rate is less than 90%.

[0090] (10) Disadvantages A 150mm x 150mm sample was cut from any point on the resin film, the surface support substrate was peeled off, and the surface was visually inspected. The number of visible white defects was counted and evaluated according to the following criteria. A: No flaws B: Number of defects is 1 or more but less than 10 C: Number of defects is 10 or more but less than 30 D: More than 30 defects.

[0091] (11) Deformation rate due to necking Before measurement, the resin film was left to stand for 24 hours in an atmosphere of 23°C and 60% RH humidity. Ten strips measuring 20 mm wide x 150 mm long were cut from either one direction of the resin film and from a direction perpendicular to it. The resin film was then peeled from the support substrate to prepare the test specimens. Using a tensile testing machine (Orientec "Tensilon" (registered trademark) UCT-100), the initial tensile chuck distance was set to 50 mm, and the tensile speed was set to 150 mm / min. After the specimen was stretched to 100% strain under a measurement temperature of 23°C and 60% RH humidity, the width (mm) of the test specimen at the center of the length (50 mm from the upper and lower chucks) was measured. Using the obtained values, the deformation rate due to necking of each test specimen was calculated using the following formula.

[0092] Deformation rate due to necking (%) = {Initial specimen width (mm) - Specimen width at 100% elongation (mm)} / Initial specimen width (mm) × 100 The average of the obtained values ​​was calculated and used as the deformation rate due to necking for that sample, and was evaluated according to the following criteria. A: Deformation rate less than 60% B: Deformation rate 60% or more but less than 70% C: Deformation rate of 70% or more.

[0093] (12) Whether or not film components leach out during pressing Prepare a 1mm thick, 200mm x 200mm stainless steel plate (SUS304, one side #800 mirror polished) and a resin film cut to 150mm x 150mm from an arbitrary position. After cleaning the SUS plate with acetone, polish the mirror-polished side with a dry cloth. Overlap the resin film onto the mirror-polished side of the SUS plate, ensuring no air is trapped underneath. If a protective film is attached to the surface of the resin film, peel off the film from the side in contact with the SUS before overlapping. Next, remove the film using a hot press and allow it to cool in the air. After cooling, peel the film from the surface of the SUS plate, visually inspect the mirror-polished side of the SUS plate, and evaluate it according to the following criteria. A: The film can be peeled off without leaving any residue on the SUS plate, and there is no clouding on the mirror-side surface of the SUS plate. B: The film can be peeled off without leaving any residue on the SUS plate, but there is some cloudiness on the mirror-finish side of the SUS plate.

[0094] (Reference Example 1) Synthesis of Half Adduct Body T1A In a 1 L four-necked flask equipped with a stirrer, condenser, thermometer, and dropping funnel, 2 moles of toluene diisocyanate and a polymerization inhibitor (BHT: dibutylhydroxytoluene) were charged. While stirring at 60°C, 2 moles of hydroxyethyl acrylate were added via a dropping funnel, and the mixture was stirred for 1 hour to obtain half-adduct compound T1A.

[0095] (Example 1) In a 1 L four-necked flask equipped with a stirrer, condenser, thermometer, and dropping funnel, 0.2 moles of isoprene homopolymer with hydroxylated ends having segments of chemical formula 3 (manufactured by Kuraray Co., Ltd., Kuraray Liquid Rubber, Mw26000) and 0.15 moles of toluene diisocyanate were charged and reacted at 80°C for 4 hours. Next, 0.1 moles of half-adduct T1A from Reference Example 1 were charged using a dropping funnel and reacted at 85°C for 5 hours. Finally, toluene was added and stirred to adjust the solid content concentration to 60% by mass, obtaining resin precursor A with Mw50,000. 105 g of resin precursor A, 1.3 g of diphenyl (2,4,6-trimethylbenzoyl)phosphine oxide as a polymerization initiator, and 35 g of glass beads with a D50 of 1.5 μm (manufactured by Fuji Seisakusho Co., Ltd., D90 / D50=2.7) were weighed and mixed to prepare a coating agent containing the segment of chemical formula 1. Next, a release film "Therapiel" (registered trademark) (Toray Industries, Inc., 38 μm thick) was cut to 210 mm x 297 mm as a support substrate, and set with the release side facing up in a tabletop coater (manufactured by BYK Gardner, automatic applicator). The clearance was adjusted so that the film thickness after drying would be 100 μm, and the coating agent was applied to the support substrate at a speed of 5 m / min. Then, the solvent was removed by heating in an oven heated to 60°C for 2 minutes to obtain a laminate of uncrosslinked resin film and support substrate. Next, with an uncrosslinked resin film on the top surface, activated energy rays are applied in a nitrogen atmosphere (light source: high-pressure mercury lamp, irradiation output: 300W / cm²). 2 Total luminous intensity: 200 J / cm² 2 The coating film was crosslinked by irradiation with ), and then the support substrate was peeled off to obtain a resin film 1 with a thickness of 100 μm.

[0096] (Example 2) A resin film 2 with a thickness of 100 μm was obtained in the same manner as in Example 1, except that 35 g of glass beads with a D50 of 12.0 μm (manufactured by Fuji Seisakusho Co., Ltd., D90 / D50=2.5) were weighed and mixed as particles.

[0097] (Example 3) A resin film 3 with a thickness of 100 μm was obtained in the same manner as in Example 1, except that 35 g of glass beads with a D50 of 5.0 μm (manufactured by Fuji Seisakusho Co., Ltd., D90 / D50=4.0) were weighed and mixed as particles.

[0098] (Example 4) A resin film 4 with a thickness of 100 μm was obtained in the same manner as in Example 1, except that 35 g of glass beads with a D50 of 5.0 μm (manufactured by Unitika Glass Beads Co., Ltd., D90 / D50=1.8) were weighed and mixed as particles.

[0099] (Example 5) A resin film 5 with a thickness of 100 μm was obtained in the same manner as in Example 1, except that 73.5 g of resin precursor A, 0.9 g of diphenyl (2,4,6-trimethylbenzoyl)phosphine oxide as a polymerization initiator, and 55 g of glass beads with a D50 of 1.5 μm (manufactured by Unitika Glass Beads Co., Ltd., D90 / D50=1.8) were weighed and mixed.

[0100] (Example 6) A resin film 6 with a thickness of 100 μm was obtained in the same manner as in Example 1, except that 150.2 g of resin precursor A, 1.9 g of diphenyl (2,4,6-trimethylbenzoyl)phosphine oxide as a polymerization initiator, and 8 g of glass beads with a D50 of 1.5 μm (manufactured by Unitika Glass Beads Co., Ltd., D90 / D50=1.8) were weighed and mixed.

[0101] (Example 7) A resin film 7 with a thickness of 100 μm was obtained in the same manner as in Example 1, except that 35 g of alumina (manufactured by Denka Co., Ltd., D90 / D50=1.9) with a D50 of 5.0 μm was weighed and mixed as particles.

[0102] (Example 8) A resin film 8 with a thickness of 100 μm was obtained in the same manner as in Example 1, except that 35 g of alumina (manufactured by Denka Co., Ltd., D90 / D50=1.9) with a D50 of 3.1 μm was weighed and mixed as particles.

[0103] (Example 9) In a 1 L four-necked flask equipped with a stirrer, condenser, thermometer, and dropping funnel, 0.2 moles of butadiene homopolymer with hydroxylated ends having segments of chemical formula 2 (manufactured by Kuraray Co., Ltd., Kuraray Liquid Rubber, Mw 28000) and 0.15 moles of toluene diisocyanate were charged and reacted at 80°C for 4 hours. Next, 0.1 moles of half-adduct T1A from Reference Example 1 were charged using a dropping funnel and reacted at 85°C for 5 hours. Finally, toluene was added and stirred to adjust the solid content concentration to 60% by mass, obtaining resin precursor B with Mw 49,000. A resin film 9 containing segments of chemical formula 3 with a thickness of 100 μm was obtained in the same manner as in Example 4, except that resin precursor B was used instead of resin precursor A.

[0104] (Example 10) In a 1 L four-necked flask equipped with a stirrer, condenser, thermometer, and dropping funnel, 0.2 moles of butadiene homopolymer with hydroxylated ends having segments of chemical formula 4 (manufactured by Nippon Soda Co., Ltd., liquid polybutadiene, Mw3200) and 0.15 moles of toluene diisocyanate were charged and reacted at 80°C for 6 hours. Next, 0.1 moles of half-adduct T1A from Reference Example 1 were charged using a dropping funnel and reacted at 85°C for 5 hours. Finally, toluene was added and stirred to adjust the solid content concentration to 60% by mass, obtaining resin precursor C with Mw51,000. A resin film 10 containing segments of chemical formula 4 with a thickness of 100 μm was obtained in the same manner as in Example 4, except that resin precursor C was used instead of resin precursor A.

[0105] (Example 11) In a 1 L four-necked flask equipped with a stirrer, condenser, thermometer, and dropping funnel, 0.43 moles of toluene diisocyanate and 0.29 moles of polytetramethylene glycol (manufactured by Mitsubishi Chemical Corporation, Mw2000) were charged, diluted with toluene to a solid content concentration of 60% by mass. The mixture was reacted at 100°C, and when the remaining isocyanate groups reached 1.4% by mass of the initial amount, the temperature was lowered to 70°C. 0.29 moles of hydroxyethyl acrylate (HEA) were added and the reaction was continued. The reaction was terminated when the remaining isocyanate groups reached 0.3% by mass of the initial amount, and toluene was added to adjust the solid content concentration to 60% by mass, yielding resin precursor D with Mw55,000. A resin film 11 containing segments of chemical formula 1 with a thickness of 100 μm was obtained in the same manner as in Example 4, except that resin precursor D was used instead of resin precursor A.

[0106] (Comparative Example 1) A particle-free resin film 12 with a thickness of 100 μm was obtained in the same manner as in Example 1, except that 163 g of resin precursor A and 2.0 g of diphenyl (2,4,6-trimethylbenzoyl)phosphine oxide were weighed and mixed to form a coating agent.

[0107] (Comparative Example 2) A resin film 13 with a thickness of 100 μm was obtained in the same manner as in Example 6, except that 8 g of alumina (manufactured by Denka Co., Ltd., D90 / D50=2.0) with a D50 of 0.6 μm was weighed and mixed with the particles.

[0108] (Comparative Example 3) A resin film 14 with a thickness of 100 μm was obtained in the same manner as in Example 6, except that 8 g of glass beads with a D50 of 20 μm (manufactured by Unitika Glass Beads Co., Ltd., D90 / D50=2.0) were weighed and mixed with the particles.

[0109] The evaluation results for the resin films collected in Examples 1-11 and Comparative Examples 1-3 are shown in the table.

[0110] [Table 1] [Industrial applicability]

[0111] The resin film of the present invention can be used as a base material for various flexible electronics due to its high elasticity, excellent composite processability with other materials, biosafety, and low elution properties. Specifically, it can be suitably used as a base material or coating material for circuits, sensors, and switches used in automobiles, energy, electrical and electronic equipment, healthcare, wellness, infrastructure, building materials, and industrial applications. In addition, from the viewpoint of high flexibility, resilience, and low elution, it can be suitably used as a base material for adhesive tapes requiring resilience, shock-absorbing materials for displays, medical film base materials, automotive surface protection film base materials, pressure sensor core materials, printed circuit boards, semiconductors, and films for the manufacturing process of electrical components such as displays, sensors, and ICs.

Claims

1. A resin film comprising a segment of chemical formula 1, wherein the average value L (%) of the elongation at break in one direction and in a direction perpendicular thereto at 23°C and 60% RH is 100% or more, and the resin film contains particles with a median diameter of 1.0 μm or more and 15 μm or less. 【Chemistry 1】 R １ This refers to a hydrogen or methyl group. R ２ This includes any of the following: Alkylene and / or arylene groups having an amide group and an ether or ester group inside Unsubstituted alkylene and / or arylene groups having an amide group and an ether or ester group inside.

2. A resin film comprising a segment of chemical formula 1, wherein the strain that shows the proportional limit in the stress-strain curve of the resin film in a tensile test at 23°C and 60% RH is 20% or more. 【Chemistry 2】 R １ This refers to a hydrogen or methyl group. R ２ This includes any of the following: Alkylene and / or arylene groups having an amide group and an ether or ester group inside Unsubstituted alkylene and / or arylene groups having an amide group and an ether or ester group inside.

3. The resin film according to claim 1, wherein the ratio of D90 to D50, D90 / D50, is 1 or more and 3 or less for the particle diameters representing 50% (D50) and 90% (D90) of the cumulative distribution of the particles.

4. The resin film according to claim 1 or 2, wherein the weight loss rate after immersion of the film in methanol at 50°C for 10 hours is 5% or less.

5. The resin film according to claim 1 or 2, wherein the particle content is 5% by mass or more and less than 50% by mass.

6. The resin film according to claim 1, wherein the particles consist of inorganic material.

7. The resin film according to claim 1 or 2, which is a cured product obtained by crosslinking a resin precursor made of urethane acrylate.

8. The resin film according to claim 1 or 3, wherein the strain that shows the proportional limit in the stress-strain curve during a tensile test at 23°C and 60% RH is 20% or more.

9. A laminate comprising a resin film according to claim 1 or 2, with a release film having a release layer disposed on at least one surface of the resin film.

10. A laminate having a sheet made of fibers on at least one side of the resin film according to claim 1 or 2.

11. A circuit comprising the resin film according to claim 1 or 2.

12. A sensor comprising the resin film according to claim 1 or 2.

13. A display comprising the resin film according to claim 1 or 2.

14. An electronic device comprising the resin film according to claim 1 or 2.

15. Automotive part comprising the resin film according to claim 1 or 2.

16. A building component comprising the resin film according to claim 1 or 2.

17. A film for electrical and electronic component manufacturing processes, comprising the resin film described in claim 1 or 2.

18. A method for manufacturing electrical and electronic components using the resin film described in claim 1 or 2 as a process film.

Images