Resin film, laminate, circuit, sensor, and electronic equipment

Abstract

To provide a resin film which is excellent in expansion / contraction durability, composite workability and biological safety.SOLUTION: A resin film contains a segment of chemical formula 1, wherein a ratio (S1 / S2) of maximum absorption peak intensity (S1) in the range of 3,100 cm-1 or more and 3,600 cm-1 in an infrared spectroscopic spectrum of an extract component in methanol after extraction treatment of the film with methanol at 40°C for 24 hours to maximum absorption peak intensity (S2) in the range of 2,700 cm-1 or more and 3,101 cm-1 or less is 0.40 or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a resin film that is excellent in stretch durability, composite processability, and biosafety. [Background technology]

[0002] With the advancement of the Internet of Things (IoT), flexible electronics that combine high flexibility and stretchability are being developed. Flexible electronics are being used in smartphones, wearable devices, security tags, automotive sensors, biosensors, strain gauges for civil engineering and building construction, and circuits and sensors for precision robots.

[0003] Flexible polyimide films are used as substrates for small devices equipped with sensors, etc. However, although they have good flexibility, they are known to have poor stretchability and recovery. Therefore, olefin elastomers and urethane elastomers are used as materials that exhibit high stretchability (Patent Documents 1 and 2).

[0004] In recent years, the use of flexible electronics in even harsher environments has been considered, and as a result, high durability is required in addition to high flexibility and stretchability, and therefore the materials that serve as the base material for flexible electronics are also required to have stretch durability. A resin film made of acrylic urethane has been proposed as a resin film for use as a base material to meet this need (Patent Document 3). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2023-137452 [Patent Document 2] Japanese Patent Application Publication No. 2019-099787 [Patent Document 3] Japanese Patent Application Publication No. 2019-81830 Summary of the Invention [Problem to be solved by the invention]

[0006] In addition to the above-mentioned properties, there are expectations for the development of devices that combine flexible electronics with other materials, and for applications in which they come into direct contact with the human body. As a result, there are demands for measures to prevent contamination of the other materials combined during use, improvements in processability, and safety for the human body.

[0007] However, the films disclosed in these technologies contain components that leach out under conditions of use, such as high temperature, high humidity, or the presence of solvents. These components leach out during use, resulting in contamination of other materials, the leaching of hydrophilic components, and the formation of a brittle surface layer, resulting in reduced adhesive strength during composite processing. Furthermore, concerns exist regarding the effects of the leachate on the human body when it comes into contact with the skin, making it difficult to achieve both stretch durability and composite processability and biosafety. The objective of the present invention is to solve the above-mentioned problems. Specifically, the present invention aims to provide a resin film that has a structure derived from acrylic functional groups but is excellent in composite processability and biosafety. [Means for solving the problem]

[0008] A preferred embodiment of the resin film of the present invention has the following features to solve the above problems. [I] A resin film containing a segment of chemical formula 1, wherein the infrared spectrum of the extracted component in methanol after extraction treatment of the film with methanol at 40°C for 24 hours is 3100 cm -1 More than 3600cm -1 The maximum absorption peak intensity (S1) in the range of 2700 cm -1 More than 3101cm -1 A resin film having a ratio (S1 / S2) of 0.40 or less to the maximum absorption peak intensity (S2) in the following range:

[0009] [ka]

[0010] R 1 refers to a hydrogen or methyl group.

[0011] R 2 refers to one of the following: An alkylene group having an amide group and an ether group or an ester group therein An arylene group having an amide group and an ether group or an ester group therein An unsubstituted alkylene group having an amide group and an ether group or an ester group inside. An unsubstituted arylene group having an amide group and an ether group or an ester group therein. [II] The resin film according to [I], wherein S1 / S2 is 0.20 or less. [III] The resin film according to [I] or [II], wherein the average breaking elongation L (%) of the film in one direction and in the direction perpendicular thereto at 23°C and 60% RH is 300% or more. [IV] The resin film according to any one of [I] to [III], wherein the average breaking stress E (MPa) of the film in one direction and in a direction perpendicular thereto at 23°C and 60% RH is 10.0 MPa or less. [V] The resin film according to any one of [I] to [IV], wherein the resin film is a cured product obtained by crosslinking a resin precursor containing at least one segment selected from the group consisting of a segment of Chemical Formula 2, a segment of Chemical Formula 3, a segment of Chemical Formula 4, and hydrogenated segments thereof.

[0012] [ka]

[0013] [ka]

[0014] [ka]

[0015] [VI] The resin film according to any one of [I] to [V], which is a cured product obtained by crosslinking a resin precursor containing a segment of Chemical Formula 5.

[0016] [ka]

[0017] R 3 indicates an alkylene group or arylene group having one or more carbon atoms. [VII] The resin film according to any one of [I] to [VI], which is a cured product obtained by crosslinking a resin precursor made of urethane acrylate. [VIII] 710cm in the infrared spectrum of resin film -1 More than 751cm -1 The maximum absorption peak intensity (S3) in the range of 750 cm -1 More than 800cm -1 The resin film according to any one of [I] to [VII], wherein the ratio (S3 / S4) to the maximum absorption peak intensity (S4) in the following range is 2.5 or more. [IX] A laminate comprising a resin film according to any one of [I] to [VIII] and a release film having a release layer disposed on at least one surface of the resin film. [X] A laminate in which a sheet made of fibers is attached to at least one surface of the resin film according to any one of [I] to [VIII]. [XI] A circuit comprising the resin film according to any one of [I] to [VIII]. [XII] A sensor comprising the resin film according to any one of [I] to [VIII]. [XIII] An electronic device comprising the resin film according to any one of [I] to [VIII]. [Effects of the Invention]

[0018] The resin film of the present invention has excellent stretch durability, composite processability, and biosafety, and can therefore be used as a substrate for various flexible electronics. Specifically, it can be suitably used as a substrate for circuits and sensors used in the automotive, energy, electrical and electronic equipment, healthcare, wellness, and infrastructure construction industries. Furthermore, in view of its high flexibility and resilience, it can be suitably used as a surface material, internal material, constituent material, or manufacturing process material for adhesive tape substrates, shock-absorbing materials for displays, medical film substrates, automotive surface protection film substrates, and pressure sensor core materials, all of which require resilience. DETAILED DESCRIPTION OF THE INVENTION

[0019] A preferred embodiment of the resin film of the present invention comprises a segment of Chemical Formula 1. Here, the segment of Chemical Formula 1 is R 2 The term "(meth)acrylic residue" 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 therein. The resin film of the present invention can exhibit excellent stretchability by having the (meth)acrylic residue.

[0020] [ka]

[0021] R 1 refers to a hydrogen or methyl group.

[0022] R 2 refers to one of the following: An alkylene group having an amide group and an ether group or an ester group therein An arylene group having an amide group and an ether group or an ester group therein An unsubstituted alkylene group having an amide group and an ether group or an ester group inside. An unsubstituted arylene group having an amide group and an ether group or an ester group therein.

[0023] The resin film of the present invention is preferably a cured product obtained by crosslinking a resin precursor containing a specific segment described below. 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 a segment of Chemical Formula 2, a segment of Chemical Formula 3, a segment of Chemical Formula 4, and segments of hydrogenated products thereof.

[0024] [ka]

[0025] [ka]

[0026] [ka]

[0027] The compounds of formulas 2 and 3 are isomers of either cis or trans isomers, and either can be used. Also, a mixture of cis and trans isomers can be used.

[0028] This embodiment allows the resin film to exhibit low polarity and high flexibility, thereby achieving both stability against solvents and flexibility.

[0029] The resin film of the present invention is preferably a cured product obtained by crosslinking a resin precursor containing a polycarbonate-based segment. Specifically, a cured product obtained by crosslinking a resin precursor containing a segment of Chemical Formula 5 is preferred from the viewpoint of stability against solvents.

[0030] [ka]

[0031] R3 indicates an alkylene group or arylene group having one or more carbon atoms.

[0032] The resin film of the present invention can be produced by crosslinking a resin precursor having the above-described segments. The resin precursor can be produced by stirring and mixing a methacrylate compound, which is a compound having one or more (meth)acryloyl groups, a diisocyanate compound, and various polyols under heating conditions.

[0033] Examples of the methacrylate compound 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.

[0034] 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.

[0035] Examples of polyols include, but are not limited to, polyether polyols, polymer polyols (polyols produced by copolymerizing acrylonitrile or styrene in polyether polyols and dispersing polymer fine particles), polyolefin polyols, polyester polyols, polycarbonate polyols, etc. Among these, polyolefin polyols and polycarbonate polyols are particularly preferred from the viewpoint of stability against solvents.

[0036] The resin film of the present invention is preferably a cured product obtained by crosslinking a precursor made of urethane acrylate, among compounds having the above-mentioned structure. Urethane acrylate is a compound obtained by a urethane reaction of polyol, polyisocyanate, and a 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 exhibited. As the urethane acrylate precursor, commercially available products can be used, or any combination of the above-mentioned compounds can be polymerized and used.

[0037] The resin film of the present invention preferably uses a polymerization initiator to promote crosslinking of the resin precursor during production. Examples of the polymerization initiator 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, benzyl dimethyl ketal, 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 the polymerization initiator include, but are not limited to, acylphosphine oxide compounds such as diphenyl-2,4,6-trimethylbenzoylphosphine oxide, benzophenone, methyl o-benzoylbenzoate, hydroxybenzophenone, 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, 2,4,6-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 alone or in combination of two or more.

[0038] Among the above, it is preferable to use a polymerization initiator composed 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 the polymerization of molecules and suppressing the production of low-molecular-weight substances containing an amide group.

[0039] 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, more preferably 10,000 or more and 80,000 or less. Possessing the above properties makes it easier to maintain both coatability when producing a film by coating and the mechanical properties described below. 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 reduced mechanical properties when the resin film is produced. If the Mw of the resin precursor is more than 100,000, coatability may be reduced during production of the resin film, which may result in reduced appearance and thickness controllability. The weight-average molecular weight of the resin precursor can be evaluated by GPC (gel permeation chromatography) measurement.

[0040] A preferred embodiment of the resin film of the present invention is a film having a peak at 3100 cm in the infrared spectrum of the extracted component in methanol after extraction treatment with methanol at 40° C. for 24 hours. -1 More than 3600cm -1 The maximum absorption peak intensity (S1) in the range of 2700 cm -1 More than 3101cm -1 The ratio (S1 / S2) of the maximum absorption peak intensity (S2) in the range below is 0.40 or less, and more preferably 0.20 or less. -1 More than 3600cm -1 The peak observed below is mainly due to the NH group, and is at 2700 cm -1 More than 3101cm -1The peaks observed below are derived from CH groups. Because NH groups are water-absorbent, by adjusting the S1 / S2 ratio in the infrared spectrum of the extracted components to the above range, the adhesive strength during composite processing due to the leaching of hydrophilic components can be controlled within a preferred range. Furthermore, the NH group-containing components extracted with methanol in the resin film of the present invention are thought to be derived from low-molecular-weight reaction by-products of the diisocyanate compounds used in producing the resin film. These reaction products can be highly irritating to the skin. If these components are present in large amounts in the resin film, they may leach out during use, raising concerns about their effects on the human body when they come into contact with the skin. An S1 / S2 ratio greater than 0.40 is undesirable because the extracted components contain a large amount of NH groups, which can lead to concerns about reduced composite processability and skin irritation. The lower limit of S1 / S2 is preferably 0.00. S1 / S2 is evaluated using the method described below. S1 / S2 can be reduced by using the specific polymerization initiator described above or by incorporating the heat treatment process described below during resin film production to reduce the amount of low-molecular-weight components.

[0041] The resin film of the present invention preferably has an average breaking elongation L (%) of 300% or more, more preferably 350% or more, in one direction of the film and in the direction perpendicular thereto at 23°C and 60% RH. By setting the average breaking elongation L within the above range, the flexibility of the resin film can be increased. If the average breaking elongation L is below 300%, the resin film may not be flexible enough when used in practice, which may lead to damage to the device. The higher the upper limit of the average breaking elongation L, the better, but the physically achievable range is 800% or less.

[0042] The resin film of the present invention preferably has an average breaking stress E (MPa) of 10.0 MPa or less, more preferably 8.0 MPa or less, in one direction of the film and in the direction perpendicular thereto at 23°C and 60% RH. By setting the average breaking stress E within the above range, the flexibility of the resin film can be increased. If the average breaking stress E exceeds 10.0 MPa, the resin film becomes significantly stiff and may lack flexibility in practical use. From a practical standpoint, the lower limit of the breaking stress of the film is preferably 1.0 MPa or more, more preferably 2.0 MPa or more. The breaking elongation and breaking stress are measured by the methods described below. The breaking elongation and breaking stress values ​​can be achieved by using a resin with the molecular weight described above.

[0043] The resin film of the present invention has a wavelength of 3100 to 3600 cm in the infrared spectrum of the resin film due to its chemical structure. -1 and 1500~1600cm -1 NH origin, 2700-3100 cm -1 and 1350~1500cm -1 , 700~850cm -1 CH origin, 1700-1750cm -1 and 1100-1250 cm -1 Depending on the structure selected, a peak derived from CO is detected in the range of 1000 to 1100 cm. -1 Peaks derived from COC may be detected in the The resin film of the present invention has a wavelength of 710 cm in the infrared spectrum of the resin film. -1 More than 751cm -1 The maximum absorption peak intensity (S3) in the range of 750 cm -1 More than 800cm -1 The ratio (S3 / S4) of the maximum absorption peak intensity (S4) in the following range is preferably 2.5 or more, more preferably 3.0 or more. -1 More than 751cm -1 The maximum absorption peak observed below is due to the aromatic CH group, at 750 cm -1 More than 800cm -1The maximum absorption peak observed below is due to the CH group of the acrylic skeleton. By using a specific polymerization initiator, the resin film of the present invention can be -1 More than 751cm -1 The maximum absorption peak intensity (S3) in the range of 750 cm -1 More than 800cm -1 The ratio (S3 / S4) to the maximum absorption peak intensity (S4) can be controlled within the following range, suppressing a decrease in composite processability and skin irritation. If S3 / S4 is less than 2.5, low molecular weight components may be more likely to be generated due to the characteristics of the polymerization initiator used when polymerizing and curing the resin film. The upper limit of S3 / S4 is 5.0 or less, which is the range that is feasible given the resin structure. S3 / S4 will be evaluated using the method described below. The resin film of the present invention preferably exhibits a weight loss rate of 8.0% or less, more preferably 5.0% or less, and even more preferably 3.0% or less, after immersion in methanol at 40°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 impurities may have adverse effects on the skin or bleed out onto the film surface, contaminating the surface. Therefore, by possessing the above properties, the film can be used in applications where it comes into contact with the human body, thereby reducing its effects on the human body and improving biosafety. Furthermore, by suppressing components that tend to bleed out during practical use, the film can further suppress deterioration of adhesion when composite processed with other components. If the weight loss rate exceeds the above range, the amount of impurities, etc., precipitated on the film surface during use may increase, causing rashes or inflammation in applications where it comes into contact with the skin, or may cause deterioration of adhesion when the film is composite processed. The preferred lower limit of the weight loss rate is 0%, which means no eluted components are present. The weight loss rate can be achieved by using a resin composition with the above-mentioned properties or by performing the heat treatment described below. The weight loss rate can be measured by the method described below.

[0044] The resin film of the present invention is not particularly limited in the number of layers, as long as it has a film-like structure by itself, and may be formed from one layer or two or more layers. Here, a layer refers to a portion having a boundary surface that can be distinguished from adjacent portions in the thickness direction and having a finite thickness. More specifically, when the cross section of the resin film is observed with an electron microscope (transmission type, scanning type) or an optical microscope, it refers to a portion that can be distinguished by the presence or absence of a discontinuous boundary surface. Even if the composition changes in the thickness direction of the resin film, if there is no such boundary surface, it is treated as a single layer.

[0045] The thickness of the resin film of the present invention is not particularly limited and is appropriately selected depending on the application. The lower limit of the thickness of the resin film is not generally determined because it is affected by the elastic modulus, breaking elongation, peeling force and peeling angle from the laminate, etc., but is preferably 5 μm or more when physical properties equivalent to those of a general flexible material are to be achieved using the laminate manufacturing method described below.

[0046] A support substrate can be laminated on one side of the resin film of the present invention. The support substrate can be a film made of either a thermoplastic resin or a thermosetting resin. Examples of the support substrate include 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, trifluorochloroethylene 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; and silicone resins. Among the above, polyester resin, polycarbonate resin, acrylic resin, or methacrylic resin is more preferable from the viewpoint of strength, heat resistance, and transparency.

[0047] The support substrate used in the present invention may have either a single layer structure or a laminate structure. In addition, the support substrate may have a functional layer such as an easy-adhesion layer, an antistatic layer, an undercoat layer, an ultraviolet absorbing layer, or a release layer previously provided on its surface.

[0048] The support substrate used in the present invention preferably has a release layer in order to control the peel 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 peel force from the resin film can be controlled to any desired degree. Examples of support substrates provided with a release layer include "Cerapeel" (registered trademark) manufactured by Toray Advanced Film Co., Ltd., "Unipeel" (registered trademark) manufactured by Unitika Ltd., "Panapeel" (registered trademark) manufactured by Panac Corporation, "Toyobo Ester" (registered trademark) manufactured by Toyobo Co., Ltd., and "Purex" (registered trademark) manufactured by Teijin Limited, and these products can also be used.

[0049] An example of a method for producing the resin film of the present invention will be specifically described below. The resin film of the present invention preferably includes the steps of applying a coating agent containing a resin precursor containing the above-mentioned segment onto a supporting 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 the release film from the laminate (step 5).

[0050] The method for applying the coating agent to the support substrate in step 1 is not particularly limited as long as it can apply the coating agent to the support substrate and form a uniform coating layer within the surface. The coating method on the film can be appropriately selected from dip coating, roller coating, wire bar coating, gravure coating, die coating, etc. Here, the coating layer refers to the "liquid layer" formed by the coating step.

[0051] 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. Drying methods include heat transfer drying (contact with a high-temperature object), convection heat transfer (hot air), radiation heat transfer (infrared rays), and others (microwaves, induction heating), but among these, in the resin film manufacturing method of the present invention, a method using convection heat transfer or radiation heat transfer is preferred because it is necessary to precisely uniform the drying speed even in the width direction.

[0052] In the crosslinking method of step 3, the coating layer from which the solvent has been removed after drying is irradiated with active energy rays to cause a reaction and crosslink the coating film.

[0053] The crosslinking by active energy rays is preferably an electron beam (EB) and / or ultraviolet rays (UV) from the viewpoint of versatility. The types of ultraviolet lamps used for irradiating ultraviolet rays include, for example, discharge lamp type, flash type, laser type, and electrodeless lamp type. When ultraviolet curing is performed using a high-pressure mercury lamp, which is a discharge lamp type, the illuminance of ultraviolet rays is 100 mW / cm. 2 More than 3,000mW / cm 2 Preferably less than 200 mW / cm 2 More than 2,000mW / cm 2 It is recommended to irradiate ultraviolet light under the following conditions: the cumulative amount of ultraviolet light is 100 mJ / cm 2 More than 3,000mJ / cm 2 Preferably less than 200 mJ / cm 2 More than 2,000mJ / cm 2 It is recommended to perform ultraviolet irradiation under the following conditions. Here, ultraviolet irradiance is the irradiation intensity per unit area, and varies depending on the lamp output, light-emitting spectral efficiency, diameter of the light-emitting bulb, design of the reflector, and the distance between the irradiated object and the light source. However, irradiance does not vary depending on the transport speed. Furthermore, the integrated ultraviolet light amount is the irradiation energy per unit area, and is the total amount of photons that reach the surface. The integrated light amount is inversely proportional to the irradiation speed passing under the light source, and proportional to the number of irradiations and the number of lamps.

[0054] The method for producing a resin film of the present invention preferably includes a step of performing a heat treatment after crosslinking by irradiation with active energy rays. This step sublimates impurities contained in the resin film, significantly suppressing the leaching of impurities from the film during use, and stabilizes the crosslinked structure formed by irradiation with active energy rays, improving mechanical properties. The temperature during the heat treatment is preferably 80°C or higher and 180°C or lower, more preferably 80°C or higher and 150°C or lower. The heat treatment time is preferably 30 seconds or higher and 18,000 seconds or lower, more preferably 60 seconds or higher and 3,600 seconds or lower. The heat treatment method is not particularly limited and can be performed using a device such as a hot air oven, a vacuum oven, or a hot plate. The heat treatment may be performed under atmospheric pressure, or under increased or reduced pressure as long as the supporting substrate or resin film is not deteriorated.

[0055] The coating agent used in producing the resin film of the present invention can be obtained by mixing, stirring, and adjusting the aforementioned resin precursor, other components, and solvent. The composition, viscosity, and solid content of the coating agent are not particularly limited as long as a resin film exhibiting the properties of the present invention can be formed.

[0056] The coating agent used in producing the resin film of the present invention may contain a solvent from the viewpoint of coatability 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, and water. One type may be used alone, or two or more types may be used in combination.

[0057] The coating agent used in producing the resin film of the present invention may contain, as a polymerizable compound other than the resin precursor, a monofunctional monomer having one polymerizable unsaturated bond, a polyfunctional monomer having two or more polymerizable unsaturated bonds, etc. Examples of monofunctional monomers include hydroxyl group-containing monofunctional (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl acrylate, and 4-hydroxybutyl acrylate, acryloylmorpholine, 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 alone or in combination of two or more, or a monofunctional monomer and a polyfunctional monomer may be used in combination.

[0058] The coating agent used in producing the resin film of the present invention may also contain antioxidants such as thermal polymerization inhibitors, ultraviolet absorbers, silane coupling agents, plasticizers, flame retardants, antistatic agents, antioxidants, antibacterial agents, antifungal agents, antifoaming agents, leveling agents, fillers, thickeners, adhesion imparting agents, thixotropy imparting agents, and lustrous materials, as long as the properties of the resin film are not impaired.

[0059] The coating agent used in producing the resin film of the present invention may contain, as an antioxidant, a hindered phenol-based or semi-hindered phenol-based radical scavenger, or a phosphite-based or thioether-based peroxide decomposer.

[0060] The resin film of the present invention may contain an acrylic copolymer, a silicone-based leveling agent, or a fluorine-based leveling agent as a leveling agent.

[0061] The resin film of the present invention may contain, as an antistatic agent, a metal salt such as a lithium salt, a sodium salt, a potassium salt, a rubidium salt, a cesium salt, a magnesium salt or a calcium salt.

[0062] The resin film of the present invention is suitable for use as a substrate for various flexible electronics due to its high stretch durability, excellent composite processability, and excellent biosafety. Specifically, it can be suitably used as a substrate for circuits and sensors used in the automotive, energy, electrical and electronic equipment, healthcare, wellness, and infrastructure construction industries. Furthermore, due to its high flexibility and resilience, it can be suitably used as a surface material, internal material, component material, or manufacturing process material for adhesive tape substrates, shock-absorbing materials for displays, medical film substrates, automotive surface protection film substrates, and pressure sensor core materials, all of which require resilience.

[0063] The resin film of the present invention can have an electrical circuit formed on at least one surface. There are no particular limitations on the method for forming the electrical circuit, and general FPC (flexible printed circuit) formation methods, as well as printing methods such as inkjet printing, flexographic printing, screen printing, gravure printing, and offset printing can be used.

[0064] The resin film of the present invention is preferably classified into categories 0 to 2, more preferably category 0 or 1, in the peel force evaluation by the cross-cut method described in JIS K5600-5-6 (1999) as an evaluation of composite processability. By having the above properties, it can be used without peeling when composited with other materials, and excellent properties can be exhibited. The above properties can be achieved by producing it using the composition and method described above. The above properties can be evaluated using the method described below.

[0065] When the resin film of the present invention is evaluated for biological safety (skin irritation) using the method described below, it is preferable that the score determined according to the Draize criteria is any of A to C, and more preferably A or B. By having the above properties, it can be used safely when used in applications where contact with the skin is expected. The above properties can be achieved by producing the film using the composition and method described above. The above properties can be evaluated using the method described below.

[0066] The resin film of the present invention can also be used to form a laminate by laminating a fiber sheet to at least one surface of the resin film. By laminating the fiber sheet, the resin film can be strengthened and its durability can be improved when used in practice. As the fiber sheet used in the laminate of the present invention, woven fabrics, knitted fabrics, and nonwoven fabrics can be suitably used.

[0067] The method for joining the laminate of the resin film and fiber sheet of the present invention is not particularly limited, and any known lamination method can be used. For example, a method using an acrylic, urethane, or epoxy adhesive, or a pressure bonding method (a pressure bonding method using a roll or press) can be used to directly bond the fiber sheet and the resin film. [Example]

[0068] (1) Identification of the segments and resin types contained in the resin film After peeling the support substrate from the surface of the resin film, the measurement was performed using FT-IR (Fourier transform infrared spectroscopy) (PerkinElmer, Frontier GOLD) with an ATR method (single reflection measurement, ATR crystal: diamond / ZnSe) with 128 accumulations and a resolution of 4 cm. -1 Infrared spectroscopy was performed using the FTIR spectroscopic data, and the various segments contained in the resin film were identified based on the detected functional group information.

[0069] In preparation for the measurement, the ATR crystal was soaked in 0.5 ml of alcohol on a Kimwipe (Nippon Paper Crecia, S-200) and then rubbed with it at least five times to clean it. The crystal was then rubbed again with an alcohol-free Kimwipe at least five times to wipe it clean, and the measurement was then performed.

[0070] When sampling, wear new nitrile gloves (TGNN10BM, manufactured by Trusco Nakayama Corporation) to avoid direct contact with the sample.

[0071] When placing the sample in the ATR, the sample is pressed onto the crystal with a pressure bar while monitoring the spectrum measurement status, and the sample is pressed down until no further changes in the spectrum occur.

[0072] The analysis software spectrum (PerkinElmer) was used for identification, and the measured spectrum was automatically corrected for ATR using the same software, after which single and multiple component searches were performed in the spectrum library to identify the resin composition. The spectrum library used is as follows: <Spectral Library> ·PKJ Library IChem / Aldrich ATR Standard IChem / Aldrich ATR Polymers, Polymer Additives IChem / Aldrich ATR Coating IChem / Aldrich paints IChem SDBS Standard Collection ·IChem SDBS polymers, polymer additives.

[0073] (2) Peak intensity ratio of methanol-extracted components (S1 / S2) A 1g sample was cut from a random location of the resin film and the support substrate was peeled off to prepare a sample. The cut sample was placed in a 50mL screw bottle, and 15g of methanol (Fujifilm Wako Pure Chemical Industries, Ltd., special grade, purity >99.8%) was weighed and added. The sample was adjusted so that it was submerged in the liquid. A stir bar was added and the bottle was sealed with laboratory film. The bottle was then subjected to extraction for 10 hours on a hot stirrer (AS ONE Corporation, LSH-4D) with stirring at 100 rpm and a top temperature of 40°C. After 10 hours, the sample was removed from the methanol and used as the extract. A cleaned glass plate was prepared and heated to 40°C on the hot stirrer. 500µL of the extract was measured and dropped onto the glass plate using a micropipette, and the methanol was evaporated. The components extracted into the methanol were collected on the glass plate. The extracted components were scraped up with a spatula and placed on an ATR crystal. Infrared spectra were obtained using the same method as in (1). The obtained IR spectrum was analyzed using the analysis software spectrum (PerkinElmer), with the vertical axis representing absorbance (abs.) and the IR spectrum at 3100 cm -1 More than 3600cm -1 The following ranges and 2700 cm -1 More than 3101cm -1 The maximum absorption peak intensities (S1 and S2) were calculated for each of the following ranges, and the maximum absorption peak intensity ratio (S1 / S2) was calculated.

[0074] (3) Peak intensity ratio of resin film (S3 / S4) The infrared spectrum obtained in (1) was analyzed using the analysis software spectrum (PerkinElmer) with the vertical axis representing absorbance (abs.) at 710 cm -1 More than 751cm -1 The following ranges and 750cm -1 More than 800cm -1 The maximum absorption peak intensities (S3 and S4) were calculated for each of the following ranges, and the maximum absorption peak intensity ratio (S3 / S4) was calculated.

[0075] (4) Breaking elongation L (%) and breaking stress E (MPa) of resin film Prior to the measurement, the resin film was left to stand for 24 hours under an atmosphere of 23°C and 60% RH humidity. Ten 10mm wide x 150mm long strips were cut from the resin film in one direction and in the direction perpendicular to the direction, and the resin film was then peeled off the support substrate to prepare test specimens. Using a tensile tester (Orientec "Tensilon" (registered trademark) UCT-100) with an initial tensile chuck distance of 50mm and a tensile speed of 300mm / min, a tensile test was performed at a temperature of 23°C and 60% RH to determine the breaking elongation (%) and breaking stress (MPa) of each test specimen. The average values ​​were calculated using the following formula, and these were defined as the breaking elongation L (%) and breaking stress E (MPa) of the sample. Breaking elongation L (%) = (average value of breaking elongation measured 10 times in any one direction) + (average value of breaking elongation measured 10 times in the perpendicular direction)) / 2 Breaking stress E (MPa) = (average value of breaking stress measured 10 times in any one direction) + (average value of breaking stress measured 10 times in the perpendicular direction) / 2.

[0076] (5) Thickness of resin film After peeling off the support substrate, the resin film was measured at any point on the resin film using a high-precision thickness meter (Nikon Corporation, DEGIMICRO MH-15M), n=5, and the average value was taken as the thickness of the resin film.

[0077] (6) Weight average molecular weight (Mw) of resin precursor The molecular weight of the resin precursor was measured as a weight average molecular weight (Mw) using a GPC (gel permeation chromatography) analyzer (HLC-8220, manufactured by Tosoh Corporation).

[0078] (7) Composite workability A resin film was fixed onto a glass plate, and a silver paste for expandable substrates (LS-453-6B, manufactured by Asahi Chemical Research Institute Co., Ltd.) was applied onto it using an applicator so that the coating thickness after drying would be 5 μm. After drying at 80°C for 30 minutes, the film was further heated at 120°C for 10 hours, and then the adhesion was evaluated according to the adhesion (cross-cut method) described in JIS K5600-5-6 (1999), and evaluated according to the classification of JIS K5600-5-6 (1999), and judged according to the following criteria. A: Category 0 and Category 1 B: Classification 2 C: Any of categories 3 to 5.

[0079] (8) Biosafety (skin irritation) The resin film was cut into a 1cm x 1cm piece, the support substrate was peeled off, and the patch was placed on the center of a 2.5cm x 2.5cm piece of adhesive tape (Nichiban, H25) to prepare a patch. The patch was applied to the dorsal skin of a shaved rabbit and left for 24 hours. The patch was then peeled off to check the condition of the skin, which was then evaluated according to the following criteria based on the Draize evaluation criteria. <Score> A: No erythema B: Very mild erythema (barely noticeable) C: Mild erythema D: Moderate to strong erythema E: Deep crimson erythema and mild crusting.

[0080] (9)Stretching durability Five 2 cm x 15 cm strips were cut from the resin film in any direction. They were placed in a DeMacha testing machine (DM-01, manufactured by Toyo Seiki Co., Ltd.) with a test length of 5 cm and n = 5, and subjected to 500 cycles of stretch fatigue at 50% elongation. The condition of the samples after the test was evaluated according to the following criteria. A: No fracture among n=5 and residual strain after fatigue treatment is less than 10% B: No fracture among n=5 and residual strain after fatigue treatment is 10% or more C: One or more of the five specimens broke during the test.

[0081] (10) Film weight loss rate (%) before and after methanol extraction Approximately 1 g of resin film was cut from any location, and the support substrate was peeled off to obtain a sample. The weight of the cut sample, x (g), was measured and placed in a 50 mL screw bottle. 15 g of methanol (Fujifilm Wako Pure Chemical Industries, Ltd., special grade, purity >99.8%) was weighed and added. The sample was submerged in the liquid, a stirrer was inserted, and the bottle was sealed with laboratory film. The extraction procedure was performed for 10 hours on a hot stirrer (AS ONE Corporation, LSH-4D) with stirring at 100 rpm at a top temperature of 40 °C. After 10 hours, the sample was removed from the methanol and dried at room temperature for 48 hours. The weight of the sample, y (g), was then measured. The weight of the sample before and after extraction was applied to the following equation to determine the film weight loss (%) before and after methanol extraction.

[0082] Film weight reduction rate (%) = {(xy) / x} × 100.

[0083] Next, the present invention will be described based on examples, but the present invention is not necessarily limited to these.

[0084] Example 1 A 1L four-neck flask equipped with a stirrer, condenser, thermometer, and dropping funnel was charged with 0.43 mol of toluene diisocyanate and 0.29 mol of polytetramethylene glycol (Mitsubishi Chemical Corporation, Mw 2000), diluted with toluene to a solids concentration of 60% by mass, and reacted at 90°C. When the residual isocyanate groups reached 1.4% by mass of the initial amount added, the temperature was lowered to 70°C, and 0.29 mol of hydroxyacrylate (HEA) was added and reacted. When the residual isocyanate groups reached 0.3% by mass of the initial amount added, the reaction was terminated, and toluene was added to adjust the solids concentration to 60% by mass, yielding Resin Precursor A with Mw 29000. 100 parts by mass of this Resin Precursor A and 2 parts by mass of diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide as polymerization initiator X were weighed and mixed to prepare a coating material containing the segment of Chemical Formula 1. Next, a release film "Therapeel" (registered trademark) (Toray Industries, Inc., thickness 50 μm) was cut into a size of 210 mm x 297 mm as a support substrate, and set with the release side facing up on a tabletop coater (BYK Gardner, automatic applicator). The clearance was adjusted so that the film thickness after drying would be 100 μm, and the coating material was applied onto the support substrate at a speed of 5 m / min. The substrate was then heated in an oven heated to 60°C for 2 minutes to remove the solvent, yielding a laminate of an uncrosslinked resin film and a support substrate. Next, the uncrosslinked resin film was placed on top and exposed to active energy rays (irradiation light source: high-pressure mercury lamp, irradiation output: 300 W / cm) in a nitrogen atmosphere. 2 , Accumulated light intensity: 200J / cm 2 ) to crosslink the coating film, and then heated in an oven heated to 120°C for 60 minutes. The support substrate was then peeled off to obtain a 100 μm thick resin film 1 containing a segment of chemical formula 1.

[0085] (Reference Example 1) Synthesis of half-adduct T1A A 1 L four-neck flask equipped with a stirrer, a condenser, a thermometer, and a dropping funnel was charged with 2 moles of toluene diisocyanate and a polymerization inhibitor (BHT: dibutylhydroxytoluene). While maintaining the temperature at 60°C and stirring, 2 moles of hydroxyethyl acrylate was added from the dropping funnel, and the mixture was stirred for 1 hour to obtain a half-adduct T1A.

[0086] Example 2 A 1-L four-neck flask equipped with a stirrer, condenser, thermometer, and dropping funnel was charged with 0.2 mol of an isoprene homopolymer having a segment of chemical formula 2 (Kuraray Co., Ltd., Kuraray Liquid Rubber, Mw 26,000) and 0.15 mol of toluene diisocyanate, and the mixture was allowed to react at 80°C for 4 hours. Next, 0.1 mol of the half-adduct T1A from Reference Example 1 was charged using a dropping funnel, and the mixture was allowed to react at 80°C for 6 hours. Finally, toluene was added and the mixture was stirred to adjust the solids concentration to 60% by mass, yielding a resin precursor B with a Mw of 45,000. A 100-μm-thick resin film 2 containing a segment of chemical formula 2 was obtained in the same manner as in Example 1, except that resin precursor B was used instead of resin precursor A and heating was not performed after crosslinking.

[0087] Example 3 Resin film 3 was obtained in the same manner as in Example 1, except that resin precursor B was used instead of resin precursor A.

[0088] Example 4 Resin precursor B was obtained in the same manner as in Example 2, and then resin film 4 was obtained in the same manner as in Example 1, except that a coating agent containing 3 parts by mass of diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide was used as polymerization initiator X.

[0089] Example 5 Resin precursor B was obtained in the same manner as in Example 2, and then resin film 5 was obtained in the same manner as in Example 1, except that a coating agent containing 2 parts by mass of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide was used as polymerization initiator Y. Example 6 A 1 L four-neck flask equipped with a stirrer, condenser, thermometer, and dropping funnel was charged with 0.2 mol of a polybutadiene homopolymer having a segment of chemical formula 3 (Kuraray Liquid Rubber, Mw 28000, manufactured by Kuraray Co., Ltd.) and 0.15 mol of toluene diisocyanate, and the mixture was allowed to react at 80°C for 4 hours. Next, 0.1 mol of the half-adduct T1A of Reference Example 1 was charged using a dropping funnel and the mixture was allowed to react at 80°C for 6 hours. Finally, toluene was added and stirred to adjust the solid concentration to 60 mass%, yielding resin precursor C with Mw 46000. A 100 μm thick resin film 6 containing a segment of chemical formula 3 was obtained in the same manner as in Example 1, except that resin precursor C was used instead of resin precursor A. Example 7 A 1-L four-neck flask equipped with a stirrer, condenser, thermometer, and dropping funnel was charged with 0.2 mol of a polybutadiene homopolymer having a segment of Chemical Formula 4 (liquid polybutadiene, Mw 3200, manufactured by Nippon Soda Co., Ltd.) and 0.15 mol of toluene diisocyanate, and the mixture was allowed to react at 80°C for 6 hours. Next, 0.1 mol of the half-adduct T1A of Reference Example 1 was charged using a dropping funnel, and the mixture was allowed to react at 80°C for 6 hours. Finally, toluene was added and the mixture was stirred to adjust the solids concentration to 60% by mass, yielding Resin Precursor D with Mw 42,000. A 100-μm-thick Resin Film 7 containing a segment of Chemical Formula 4 was obtained in the same manner as in Example 1, except that Resin Precursor D was used instead of Resin Precursor A.

[0090] Example 8 A 1L four-neck flask equipped with a stirrer, condenser, thermometer, and dropping funnel was charged with 0.43 moles of toluene diisocyanate and 0.29 moles of polycarbonate diol (UBE Corporation, Mw 3200) having a segment of chemical formula 5 diluted with methyl ethyl ketone to a solids concentration of 60% by mass, and the mixture was reacted at 90 ° C. When the residual isocyanate groups reached 1.4% by mass of the initial amount, the temperature was lowered to 70 ° C., 0.29 moles of hydroxyacrylate was added and the reaction was terminated when the residual isocyanate groups reached 0.3% by mass of the initial amount, and methyl ethyl ketone was added to adjust the solids concentration to 60% by mass, yielding a resin precursor E with a Mw of 35,000. A 100 μm thick resin film 8 containing a segment of chemical formula 5 was obtained in the same manner as in Example 1, except that resin precursor E was used instead of resin precursor A.

[0091] (Comparative Example 1) A resin film 9 having a thickness of 100 μm and containing a segment of chemical formula 1 was obtained in the same manner as in Example 1, except that the resin precursor A described in Example 1 was used, a coating agent prepared by weighing and mixing 2 parts by mass of 1-hydroxycyclohexyl phenyl ketone as the polymerization initiator Z was used, and heating was not performed after crosslinking.

[0092] (Comparative Example 2) A 1L four-neck flask equipped with a stirrer, condenser, thermometer, and dropping funnel was charged with 0.43 moles of toluene diisocyanate and 0.29 moles of polytetramethylene glycol (Mitsubishi Chemical Corporation, Mw 2000), diluted with toluene to a solids concentration of 60% by mass, and reacted at 90°C. When the residual isocyanate groups reached 1.4% by mass of the initial amount added, the temperature was lowered to 70°C, and 0.58 moles of hydroxyacrylate was added and reacted. When the residual isocyanate groups reached 0.3% by mass of the initial amount added, the reaction was terminated, and toluene was added to adjust the solids concentration to 60% by mass, yielding a resin precursor F with a Mw of 84,000. A 100 μm-thick resin film 10 containing a segment of chemical formula 1 was obtained in the same manner as in Comparative Example 1, except that a coating agent prepared by weighing and mixing 100 parts by mass of this resin precursor F and 2 parts by mass of 1-hydroxycyclohexyl phenyl ketone as polymerization initiator Z was used.

[0093] The evaluation results for the resin films collected in Examples 1 to 8 and Comparative Examples 1 and 2 are shown in the table below.

[0094] [Table 1]

[0095] [Table 2]

[0096] [Table 3] [Industrial Applicability]

[0097] The resin film of the present invention has high stretch durability, excellent processability for composite processing with other materials, and excellent biosafety, making it suitable for use as a substrate for various flexible electronics. Specifically, it can be suitably used as a substrate for circuits and sensors used in the automotive, energy, electrical and electronic equipment, healthcare, wellness, and infrastructure construction industries. Furthermore, in view of its high flexibility and resilience, it can be suitably used as a surface material, internal material, constituent material, or manufacturing process material for adhesive tape substrates, shock-absorbing materials for displays, medical film substrates, automotive surface protection film substrates, and pressure sensor core materials, all of which require resilience.

Claims

1. A resin film containing a segment of Chemical Formula 1, wherein the infrared spectrum of the extracted component in methanol after extraction treatment of the film with methanol at 40°C for 24 hours is 3100 cm －１ More than 3600cm －１ The maximum absorption peak intensity (S1) in the range of 2700 cm －１ More than 3101cm －１ A resin film having a ratio (S1 / S2) of 0.40 or less to the maximum absorption peak intensity (S2) in the following range. 【Chemical 1】 R １ refers to a hydrogen or methyl group. R ２ refers to one of the following: An alkylene group having an amide group and an ether group or an ester group therein An arylene group having an amide group and an ether group or an ester group therein An unsubstituted alkylene group having an amide group and an ether group or an ester group inside. An unsubstituted arylene group having an amide group and an ether group or an ester group therein.

2. The resin film according to claim 1, wherein S1 / S2 is 0.20 or less.

3. 3. The resin film according to claim 1, wherein the average breaking elongation L (%) of the film in one direction and in a direction perpendicular thereto at 23°C and 60% RH is 300% or more.

4. 3. The resin film according to claim 1, wherein the average breaking stress E (MPa) of the film in one direction and in a direction perpendicular thereto at 23°C and 60% RH is 10.0 MPa or less.

5. 3. The resin film according to claim 1, wherein the resin film is a cured product obtained by crosslinking a resin precursor including at least one segment selected from the group consisting of a segment of Chemical Formula 2, a segment of Chemical Formula 3, a segment of Chemical Formula 4, and a segment of a hydrogenated product thereof. 【Chemistry 2】 【Chemistry 3】 【Chemistry 4】

6. The resin film according to claim 1 or 2, wherein the resin film is a cured product obtained by crosslinking a resin precursor containing a segment of Chemical Formula 5. 【Chemistry 5】 R ３ indicates an alkylene group or arylene group having one or more carbon atoms.

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

8. 710 cm in the infrared spectrum of the resin film －１ 751cm or more －１ The maximum absorption peak intensity (S3) in the range of 750 cm －１ More than 800cm －１ The resin film according to claim 1 or 2, wherein the ratio (S3 / S4) to the maximum absorption peak intensity (S4) in the following range is 2.5 or more.

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

10. A laminate comprising the resin film according to claim 1 or 2 and a sheet made of fiber attached to at least one surface of the resin film.

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

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

13. An electronic device comprising the resin film according to claim 1.

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