Intermediate film, laminate, and method for producing intermediate film

Abstract

The intermediate film according to the present invention contains an ionomer resin and an ultraviolet absorber, and the ultraviolet absorber is at least one type selected from the group consisting of compounds having a benzotriazole structure represented by formula (I) and compounds having a triazine structure. The present invention makes it possible to provide an intermediate film containing an ionomer resin which has little discoloration and suppresses ultraviolet transmittance. (In the formula, R1 is an organic group having 4 or more carbon atoms, and R2-R8 are each independently a hydrogen atom, a halogen atom, or an organic group having 1-20 carbon atoms)

Description

Technical Field

[0001] This invention relates to an intermediate film, a laminate, and a method for manufacturing the intermediate film. Background Technology

[0002] Laminated glass, even when broken by external impact, will not shatter into glass fragments, making it safe and widely used in windows in buildings, automobiles, railway vehicles, aircraft, and ships. Laminated glass is generally understood to be an integrated structure consisting of a laminate containing a thermoplastic resin sandwiched between two panes of glass. In buildings, besides windows, laminated glass is also used in glass floors or curtain walls. In these applications, laminated glass is sometimes large-sized and used as structural glass windows.

[0003] Ionomer resins have been conventionally used in interlayers for laminated glass. Known ionomer resins used in interlayers for laminated glass include ethylene-unsaturated carboxylic acid copolymers, such as ethylene-(meth)acrylic acid copolymers, wherein at least a portion of the carboxyl groups in the side chains are crosslinked between molecular chains by metal cations (e.g., see Patent Documents 1-3).

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: International Publication No. 2021 / 002326

[0007] Patent Document 2: Japanese Patent Application Publication No. 2022-120218

[0008] Patent Document 3: Japanese Patent Application Publication No. 2019-77582 Summary of the Invention

[0009] The problem the invention aims to solve

[0010] Ionomer resins typically do not absorb ultraviolet light. When it is desired to reduce the ultraviolet transmittance of an intermediate film containing an ionomer resin, an ultraviolet absorber must be included. Examples of blending ultraviolet absorbers into ionomer resins are disclosed in embodiments of Patent Documents 1-3.

[0011] However, the inventors' research in this application has shown that adding an ultraviolet absorber to an intermediate film containing an ionomer resin causes the intermediate film to become discolored, resulting in an unattractive appearance.

[0012] Therefore, the object of the present invention is to provide an intermediate film containing an ionomer resin, wherein ultraviolet transmittance is reduced and coloring is less.

[0013] means for solving problems

[0014] The inventors of this application conducted in-depth research and found that by using an intermediate film containing an ionomer resin and at least one ultraviolet absorber selected from compounds having a benzotriazole structure represented by the following formula (I) and compounds having a triazine structure, the above-mentioned problems can be solved, and the present invention was completed.

[0015] The gist of this invention is as follows.

[0016] [1] An intermediate film comprising an ionomer resin and an ultraviolet absorber, wherein the ultraviolet absorber is at least one selected from compounds having a benzotriazole structure represented by the following formula (I) and compounds having a triazine structure:

[0017] [Chemical Formula 1]

[0018]

[0019] In the above formula, R1 is an organic group with 4 or more carbon atoms, and R2 to R8 are each an independent hydrogen atom, halogen atom, or organic group with 1 to 20 carbon atoms.

[0020] [2] According to the intermediate membrane described in [1], wherein the compound having the benzotriazole structure is any one of the compounds represented by the following formulas (2) to (4).

[0021] [Chemical Formula 2]

[0022]

[0023] [3] According to the intermediate film of [1] or [2], wherein the content of the ultraviolet absorber is 0.01 to 1 part by mass relative to 100 parts by mass of ionomer resin.

[0024] [4] The intermediate membrane according to any one of [1] to [3], wherein the ionomer resin comprises at least one of magnesium and zinc.

[0025] [5] The intermediate membrane according to any one of [1] to [4], wherein the intermediate membrane comprises a silane coupling agent.

[0026] [6] According to the intermediate membrane of [5], wherein the silane coupling agent is a silane coupling agent having an epoxy group.

[0027] [7] According to the intermediate membrane of [5], wherein the intermediate membrane contains 0.01% to 0.5% by mass of silane coupling agent based on 100% by mass of the intermediate membrane as a whole.

[0028] [8] The intermediate film according to any one of [1] to [7], wherein the intermediate film is used as a sealing material for photovoltaic solar cells.

[0029] [9] A resin composition comprising an ionomer resin and an ultraviolet absorber, wherein the ultraviolet absorber is at least one selected from compounds having a benzotriazole structure represented by the following formula (I) and compounds having a triazine structure:

[0030] [Chemical Formula 3]

[0031]

[0032] In the above formula, R1 is an organic group with 4 or more carbon atoms, and R2 to R8 are each an independent hydrogen atom, halogen atom, or organic group with 1 to 20 carbon atoms.

[0033]

[10] According to the resin composition of [9], wherein the compound having a benzotriazole structure is any one of the compounds represented by the following formulas (2) to (4).

[0034] [Chemical Formula 4]

[0035]

[0036]

[11] The resin composition according to [9] or

[10] , wherein the resin composition is a resin composition obtained by compounding an ionomer resin, an ultraviolet absorber and an ethylene-(meth)acrylic acid copolymer.

[0037]

[12] A laminate comprising an intermediate film according to any one of [1] to [8] and a pair of substrates, wherein the intermediate film is disposed between the pair of substrates.

[0038]

[13] According to the laminate of

[12] , wherein the substrate is a substrate selected from organic material substrates and inorganic material substrates.

[0039]

[14] The laminate according to

[12] or

[13] , wherein the laminate is a laminated glass.

[0040]

[15] The laminate according to

[12] or

[13] , wherein the laminate is a laminated glass for building structure.

[0041]

[16] A display comprising a stack according to

[12] or

[13] .

[0042]

[17] A photovoltaic solar cell comprising a stack according to

[12] or

[13] .

[0043]

[18] A method for manufacturing an intermediate film according to any one of [1] to [8], comprising: a step of compounding an ionomer resin, an ultraviolet absorber and an ethylene-(meth)acrylic acid copolymer to obtain a resin composition; and

[0044] The process of extruding the resin composition.

[0045] Invention Effects

[0046] The present invention can provide an intermediate film with reduced ultraviolet transmittance and less coloring. Attached Figure Description

[0047] Figure 1 The λ1-λ2 in this invention are illustrated schematically.

[0048] [Intermediate membrane]

[0049] The intermediate membrane of the present invention contains an ionomer resin and an ultraviolet absorber, wherein the ultraviolet absorber is at least one selected from compounds having a benzotriazole structure represented by the following formula (I) and compounds having a triazine structure.

[0050] <UV absorber>

[0051] The intermediate film of this invention contains an ultraviolet absorber. By containing an ultraviolet absorber, the ultraviolet shielding property of the intermediate film is improved.

[0052] The ultraviolet absorber is selected from at least one compound having a benzotriazole structure represented by formula (I) and a triazine structure. By including this specific ultraviolet absorber, it is easier to prevent the intermediate film from being colored.

[0053] Although the reasons are not entirely clear, it appears that the use of UV absorbers with specific structures makes it difficult for the metal ions contained in the ionomer resin to coordinate with the UV absorbers, making it less likely that the intermediate film will be colored.

[0054] [Chemical Formula 5]

[0055]

[0056] (In the above formula, R1 is an organic group with 4 or more carbon atoms, and R2 to R8 are each an independent hydrogen atom, halogen atom, or organic group with 1 to 20 carbon atoms).

[0057] In formula (I) above, R1 is an organic group with 4 or more carbon atoms. Therefore, the intermediate film is unlikely to be colored. Although the reason is not entirely clear, it seems that R1 being an organic group with 4 or more carbon atoms adjacent to the hydroxyl group in formula (I) makes it difficult for the ultraviolet absorber to coordinate with the metal of the ionomer resin, thus making it unlikely that the intermediate film will be colored.

[0058] To prevent the intermediate film from being colored, R1 is preferably an organic group with 4 to 20 carbon atoms, more preferably an organic group with 4 to 10 carbon atoms. R1 may also contain oxygen atoms, nitrogen atoms, sulfur atoms, etc., but is preferably a hydrocarbon group.

[0059] That is, R1 is preferably a hydrocarbon group with 4 or more carbon atoms, more preferably a hydrocarbon group with 4 to 20 carbon atoms, and even more preferably a hydrocarbon group with 4 to 10 carbon atoms.

[0060] Furthermore, R1 preferably includes quaternary carbon atoms and / or aromatic rings.

[0061] This structure appears to make it difficult for UV absorbers to coordinate with the metals of the ionomer resin, making it unlikely that the intermediate film will be colored.

[0062] R1 is particularly preferred to be a group represented by the following formula (a) or formula (b).

[0063] [Chemical Formula 6]

[0064]

[0065] Equations (a) and (b) It is a bond that connects to the aromatic ring shown in formula (I).

[0066] In formula (I) above, R2 to R8 are each independently a hydrogen atom, a halogen atom, or an organic group having 1 to 20 carbon atoms. Examples of halogen atoms include fluorine, chlorine, bromine, and iodine, with chlorine being preferred. The organic group may, for example, contain oxygen, nitrogen, and sulfur atoms, and may be a hydrocarbon group.

[0067] In formula (I) above, R2, R4, R5, R6, R7 and R8 are preferably hydrogen atoms, alkyl, aryl, alkoxy, aryloxy, acyloxy, alkylamino, aniline, acylamino, alkylsulfonylamino, arylsulfonylamino, alkylthio or arylthio, and more preferably hydrogen atoms.

[0068] In formula (I) above, R3 is a hydrogen atom or an organic group having 1 to 20 carbon atoms. The organic group may include, for example, oxygen, nitrogen, or sulfur atoms, and may be a hydrocarbon group. To prevent the intermediate film from being colored, R3 is preferably an organic group having 1 to 10 carbon atoms, more preferably a hydrocarbon group having 1 to 10 carbon atoms, or an organic group having 1 to 10 carbon atoms with an ester structure. Furthermore, the hydrocarbon group having 1 to 10 carbon atoms preferably includes a quaternary carbon atom and / or an aromatic ring.

[0069] R3 is particularly preferred to be a group represented by the following formula (c), formula (d) or formula (e).

[0070] [Chemical Formula 7]

[0071]

[0072] Equations (c), (d), and (e) It is a bond that connects to the aromatic ring shown in formula (I).

[0073] To prevent the intermediate film of the present invention from being colored, the compound having a benzotriazole structure represented by formula (I) is preferably any compound represented by formula (2) to (4), and more preferably a compound represented by formula (2) or formula (3).

[0074] [Chemical Formula 8]

[0075]

[0076] There is no particular limitation on the types of compounds with a triazine structure. A triazine structure refers to an unsaturated six-membered ring structure containing three nitrogen atoms, and specific examples include 1,2,3-triazine, 1,2,4-triazine, and 1,3,5-triazine.

[0077] To ensure that the intermediate film is unlikely to be colored, compounds with a triazine structure are preferably 2-[4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine-2-yl]-5-(octoxy)phenol.

[0078] The ultraviolet absorber may be a compound having a benzotriazole structure represented by formula (I) and may be a compound having a triazine structure, but in order to increase the ultraviolet shielding of the intermediate film, a compound having a benzotriazole structure represented by formula (I) is preferred.

[0079] The content of the UV absorber in the interlayer, relative to 100 parts by weight of the ionomer resin, is preferably 0.01 parts by weight or more, more preferably 0.05 parts by weight or more, even more preferably 0.1 parts by weight or more, and preferably 3 parts by weight or less, even more preferably 2 parts by weight or less, even more preferably 1.5 parts by weight or less, and even more preferably 1 part by weight or less. Having a UV absorber content at least at the lower limit will further improve the UV blocking performance of the interlayer. At the same time, having a UV absorber content not exceeding the upper limit will ensure that the interlayer is unlikely to be colored.

[0080] <Ionomer Resins>

[0081] The intermediate membrane of this invention contains an ionomer resin. Examples of ionomer resins include ionomer resins of ethylene-unsaturated carboxylic acid copolymers. Ionomer resins are typically obtained by neutralizing ethylene-unsaturated carboxylic acid copolymers with metal ions.

[0082] Examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, 2-ethylacrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, maleic anhydride, fumaric anhydride, itaconic anhydride, monomethyl maleate, and monoethyl maleate, with acrylic acid and methacrylic acid being preferred. Therefore, the ionomer resin is preferably an ionomer resin of an ethylene-(meth)acrylic acid copolymer.

[0083] Examples of metal ions include lithium, potassium, sodium, silver, copper, calcium, magnesium, titanium, zinc, aluminum, barium, beryllium, strontium, tin, lead, iron, cobalt, nickel, cadmium, and mercury ions, with magnesium and zinc being preferred. Metal ions can be used alone or in combination with two or more. When the ionomer resin contains at least one of magnesium and zinc, especially magnesium, a suitable cross-linked structure is formed, facilitating an increase in the glass transition temperature and rigidity of the interlayer.

[0084] On the other hand, the inventors of this application have discovered that when the metal ion used in the ionomer is magnesium, the intermediate film is more likely to be colored. As in this invention, using a specific ultraviolet absorber will ensure that coloring is unlikely to occur, even when an easily coloring ionomer is used.

[0085] Furthermore, (meth)acrylic acid means at least one of methacrylic acid or acrylic acid, and the same applies to similar terms below.

[0086] Ionomer resins of ethylene-unsaturated carboxylic acid copolymers typically contain structural units (A) derived from unsaturated carboxylic acids, structural units (B) derived from neutralized unsaturated carboxylic acids, and structural units (C) derived from ethylene.

[0087] Ionomer resins of ethylene-(meth)acrylic acid copolymers typically contain structural units derived from (meth)acrylic acid (structural unit (A)), structural units derived from neutralized (meth)acrylic acid (structural unit (B)), and structural units (C) derived from ethylene. These structural units (A), (B), and (C) contained in the ionomer resin facilitate the addition of rigidity.

[0088] The monomer forming structural unit (A) is not particularly limited as long as it is an unsaturated carboxylic acid, but is preferably at least one of acrylic acid and methacrylic acid, and is more preferably methacrylic acid, for example, for rigidity and adhesion. Structural unit (A) is a structural unit that has not been neutralized by metal ions.

[0089] Structural unit (B) is a structural unit derived from the above-mentioned neutralized unsaturated carboxylic acid, but preferably a structural unit derived from at least one of neutralized acrylic acid and methacrylic acid, more preferably a structural unit derived from neutralized methacrylic acid. Structural unit (B) is preferably a neutralized unit of the above-mentioned structural unit (A).

[0090] Structural unit (B) is a structural unit in which a hydrogen ion of the carboxyl group in an unsaturated carboxylic acid is replaced by a metal ion. That is, the neutralized unsaturated carboxylic acid in structural unit (B) is a metal salt of the unsaturated carboxylic acid. The metal ion in the metal salt is as described above, but preferably at least one of magnesium and zinc, with magnesium being particularly preferred.

[0091] Therefore, structural unit (B) preferably contains at least one of magnesium and zinc, and particularly preferably contains magnesium.

[0092] In the ionomer resin, the total content of structural units (A) and (B), based on the total amount of structural units forming the ionomer resin, is preferably 10% to 25% by mass. When the total content of structural units (A) and (B) is 10% by mass or more, good intermediate film transparency, heat resistance, and mechanical strength can be achieved, for example. When the total content is 25% by mass or less, flexibility, processability, and adhesion can also be enhanced, for example. The total content of structural units (A) and (B) is more preferably 11% to 23% by mass, and even more preferably 12% to 20% by mass.

[0093] In the ionomer resin, the content of structural unit (B) is preferably 4% to 18% by mass, based on the total amount of structural units forming the ionomer resin. A content of 4% by mass or more of structural unit (B) increases the degree of crosslinking of the ionomer resin, making it easier to increase the rigidity of the ionomer resin. A content of 4% by mass or more, for example, further facilitates increased transparency and heat resistance. A content of 18% by mass or less of structural unit (B) also, for example, facilitates enhanced flexibility, adhesion, mechanical strength, and processability of the interlayer film.

[0094] The content of structural unit (B) in the ionomer resin is more preferably 6% to 17.5% by mass, even more preferably 7% to 16% by mass, and even more preferably 10% to 14% by mass.

[0095] To facilitate the improvement of the impact resistance of the ionomer resin, the content of ethylene-derived structural units (C) is preferably 70% by mass or more, more preferably 75% by mass or more, further preferably 80% by mass or more, and even more preferably 82% by mass or more, based on the total amount of structural units forming the ionomer resin. For the sake of transparency, mechanical strength, and processability, the content of ethylene-derived structural units (C) is preferably 90% by mass or less, more preferably 89% by mass or less, further preferably 88% by mass or less, and even more preferably 85% by mass or less.

[0096] In the ionomer resin, the content of structural unit (A) is not particularly limited, but based on the total amount of structural units forming the ionomer resin, it is preferably 3% to 10% by mass, more preferably 4% to 9% by mass, and even more preferably 8% or less by mass.

[0097] Ionomer resins may contain structural units other than structural units (A), (B), and (C) (hereinafter referred to as "other structural units"). Therefore, ionomer resins can be obtained either by neutralizing copolymers of ethylene and unsaturated carboxylic acids with metal ions, or by neutralizing copolymers of ethylene, unsaturated carboxylic acids, and monomers other than ethylene and unsaturated carboxylic acids with metal ions.

[0098] Examples of these other structural units include structural units (D) derived from alkyl (meth)acrylates. The presence of structural unit (D) allows for adjustment of, for example, the glass transition temperature (Tg) of ionomer resins. Examples of alkyl (meth)acrylates include those with approximately 1 to 10 carbon atoms, such as methyl (meth)acrylate, ethyl (meth)acrylate, isobutyl (meth)acrylate, n-butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate.

[0099] To prevent an unnecessarily decrease in the glass transition temperature, the content of the structural unit (D) derived from (meth)acrylate is preferably 15% by mass or less, more preferably 8% by mass or less, even more preferably 4.5% by mass or less, and even more preferably 2% by mass or less. The lower the content of the structural unit (D), the better it is to increase rigidity without causing a decrease in the glass transition temperature. The content can be 0% by mass or more, but it is preferable that the ionomer resin does not contain the structural unit (D).

[0100] Isobutyl methacrylate is typically preferred as an alkyl methacrylate in the ionomer resin. However, in this invention, the ionomer resin preferably contains no or only a small amount of structural units derived from isobutyl methacrylate. Therefore, the content of structural units derived from isobutyl methacrylate is preferably 15% by mass or less, more preferably 8% by mass or less, further preferably 4.5% by mass or less, and even more preferably 2% by mass or less. The content of structural units derived from isobutyl methacrylate may also be 0% by mass or more, but the ionomer resin preferably does not contain structural units derived from isobutyl methacrylate.

[0101] In addition, ionomer resins may also contain structural units other than structural units (A), (B), (C), and (D) as other structural units, such as structural units derived from vinyl acetate and vinyl propionate.

[0102] In this invention, the degree of neutralization of the ionomer resin is, for example, 30% or more, but for higher rigidity, a degree of neutralization of 40% or more is preferred, more preferably 42% or more, further preferably 45% or more, and even more preferably 50% or more.

[0103] Furthermore, in this invention, by including at least one of magnesium and zinc (especially magnesium) in the structural unit (B) and by increasing the degree of neutralization, it is easier to achieve better rigidity.

[0104] The degree of neutralization of the ionomer resin is not particularly limited, but for better flexibility, adhesion, mechanical strength and processability of the intermediate film, a degree of neutralization of 95% or less is preferred, more preferably 90% or less, further preferably 80% or less, and even more preferably 75% or less.

[0105] The neutralization degree of ionomer resin refers to the percentage (%) of all carboxyl groups contained in the ionomer resin that have been neutralized by metal ions.

[0106] The degree of neutralization in the aforementioned ionomer resin can be determined by IR analysis before and after hydrochloric acid treatment. Specific methods are described in the examples described later.

[0107] In addition, mass spectrometry analysis and 1 H-NMR analysis was used to calculate the content of each structural unit in the ionomer resin based on the integral intensity ratio of the hydrogen peaks originating from each monomer and the degree of neutralization.

[0108] For processability and mechanical strength, the melt flow rate (MFR) of the ionomer resin is determined according to JIS K7210:1999, at 190°C and 2160 g load, for example, from 0.01 g / 10 min to 150 g / 10 min, preferably from 0.01 g / 10 min to 50 g / 10 min, more preferably from 0.1 g / 10 min to 30 g / 10 min, and even more preferably from 0.1 g / 10 min to 10 g / 10 min.

[0109] With the interlayer film comprising 100% by mass, the content of ionomer resin in the interlayer film is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and even more preferably 88% by mass or more. Ensuring that the content of ionomer resin meets the above-mentioned lower limits will enhance, for example, the rigidity and interlayer adhesion of the resulting laminated glass.

[0110] In addition, based on the total mass of the intermediate membrane being 100%, the content of ionomer resin in the intermediate membrane can be less than 100% by mass. However, in order to ensure at least a certain amount of additive content, the content of ionomer resin can be, for example, less than 99.99% by mass or less than 99.9% by mass.

[0111] When the ionomer resin in the intermediate membrane contains other resin components, the content of the ionomer resin in the intermediate membrane should not exceed a certain amount, such as 98% by mass or 97% by mass or less.

[0112] The manufacturing method of ionomer resin is not particularly limited and can be manufactured by known methods, for example, by obtaining an ethylene-unsaturated carboxylic acid copolymer by free radical polymerization of the monomer components under high temperature and high pressure, and then reacting the copolymer with a metal compound.

[0113] <Other Resin Components>

[0114] The intermediate film of the present invention may also contain other resin components besides the ionomer resin described above. The viscosity of the ionomer resin may be too high during compounding, leading to decreased extrudability; however, the presence of other resin components in the intermediate film of the present invention ensures better extrudability. These other resin components should preferably be compatible with the ionomer resin described above. For compatibility with the ionomer resin, the other resin components are preferably ethylene-unsaturated carboxylic acid copolymers. Here, the unsaturated carboxylic acid used in the ethylene-unsaturated carboxylic acid copolymer is as described above, with (meth)acrylic acid being preferred, and methacrylic acid being more preferred.

[0115] For compatibility and extrudability, other resins are preferably copolymers of the same type as those used in the ionomer resin described above, and even more preferably resins before neutralization with metal ions are used to obtain the ionomer resin described above.

[0116] Therefore, when the above-mentioned ionomer resin is an ionomer resin of ethylene-(meth)acrylic acid copolymer, other resins are preferably ethylene-(meth)acrylic acid copolymers.

[0117] When other resin components are used, the content of other resin components is 1.5% to 25% by mass, based on 100% by mass of the intermediate film. Ensuring that the content of other resin components is at least 2% by mass will reduce the viscosity of the aforementioned ionomer resin, resulting in better extrudability. When other resin components are included, ensuring that the content is not greater than 25% by mass will prevent a decrease in rigidity. Based on 100% by mass of the intermediate film, the content of other resin components is more preferably 2.5% to 18% by mass, and even more preferably 3.5% to 12% by mass.

[0118] <Silane Coupling Agent>

[0119] The interlayer film may contain silane coupling agents as additives. The presence of silane coupling agents will facilitate the enhancement of the interlayer film's adhesion to, for example, substrates and glass.

[0120] The inventors of this application have discovered that the adhesion of interlayer films containing ionomer resins to glass differs from that of interlayer films containing polyvinyl acetal resins. Specifically, they found that interlayer films containing ionomer resins exhibit lower adhesion to the top surface of float glass than to the bottom surface. Further research revealed that adding a silane coupling agent to the interlayer film containing ionomer resins provides excellent adhesion to any glass surface.

[0121] Examples of silane coupling agents include reagents having functional groups such as epoxy, amino, and groups containing polymerizable carbon-carbon double bonds such as vinyl and (meth)acryloyl groups; and hydrolyzable groups such as alkoxy groups.

[0122] Examples of silane coupling agents having polymerizable carbon-carbon double bonds include vinyltrimethoxysilane, vinyltriethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropylmethyldimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-acryloxypropylmethyldiethoxysilane, and 3-acryloxypropyltriethoxysilane.

[0123] Examples of amino-containing silane coupling agents include hydrochlorides of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, and N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane.

[0124] Examples of epoxy-based silane coupling agents include 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-epoxypropoxypropylmethyldimethoxysilane, 3-epoxypropoxypropyltrimethoxysilane, 3-epoxypropoxypropylmethyldiethoxysilane, and 3-epoxypropoxypropyltriethoxysilane.

[0125] The intermediate membrane can contain only one silane coupling agent or a combination of two or more.

[0126] Among these reagents, silane coupling agents with amino groups are preferred for better adhesion to glass and substrates, with silane coupling agents having an ethylenediamine structure being particularly preferred, such as N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane and N-2-(aminoethyl)-3-aminopropyltriethoxysilane.

[0127] For better glass-to-substrate adhesion and even lower yellowness index of the interlayer, epoxy-based silane coupling agents are preferred, with 3-epoxypropoxypropylmethyldimethoxysilane and 3-epoxypropoxypropylmethyldiethoxysilane being even more preferred.

[0128] For better adhesion between the glass and the substrate, the content of silane coupling agent in the intermediate film is preferably 0.001% to 5% by mass, more preferably 0.005% to 2% by mass, even more preferably 0.01% to 1% by mass, and even more preferably 0.01% to 0.5% by mass, and even more preferably 0.05% to 0.5% by mass, based on 100% of the total mass of the intermediate film.

[0129] The upper limit is not specifically limited, but based on the total mass of the intermediate membrane as 100%, the content of silane coupling agent is preferably 0.5% by mass or less, more preferably 0.2% by mass or less.

[0130] <Other Additives>

[0131] In addition to the aforementioned UV absorbers and silane coupling agents, the intermediate membrane may contain at least one of antioxidants and other known additives.

[0132] Examples of antioxidants include phenolic compounds, phosphoric acid compounds, and sulfur compounds. Antioxidants can prevent oxidative degradation of the intermediate film, resulting in better durability.

[0133] Antioxidants can be used alone or in combination of two or more.

[0134] In addition to the additives mentioned above, other additives that may be contained in the sandwich membrane of the present invention include plasticizers, light stabilizers, antistatic agents, surfactants, colorants, foaming agents, lubricants, crystallization nucleating agents, crystallization promoters, crystallization delay agents, catalyst deactivators, heat absorbers, heat reflectors, heat dissipation agents, inorganic fillers, organic fillers, impact resistance modifiers, slip agents, crosslinking agents, crosslinking aids, tackifiers, processing aids, release agents, hydrolysis inhibitors, anti-blocking agents, antifogging agents, flame retardants, flame retardant additives, light diffusing agents, antibacterial agents, antifungal agents, and dispersants.

[0135] <Difference between λ1 and λ2 (λ1-λ2)>

[0136] The intermediate film of the present invention is preferably an intermediate film in which the difference (λ1-λ2) between wavelength λ1 (nm) and wavelength λ2 (nm) described below is less than 20 nm.

[0137] As determined in the transmittance analysis of laminated glass obtained by sandwiching an interlayer between two pieces of transparent glass with a thickness of 2.5 mm, wavelength λ1 is the smallest wavelength (nm) in which the increase in transmittance (%) is less than 1 relative to the increase in wavelength (nm) when the wavelength is 300~460 nm and the light transmittance is at least 10%.

[0138] In a solution of ultraviolet absorber with the same concentration (mass%) as the ultraviolet absorber contained in the intermediate membrane, the wavelength λ2 is determined in a transmittance analysis of the solution under the following standard optical path length L (mm), where the wavelength is 300~460 nm and the light transmittance is at least 10%, and the increase in transmittance (%) is less than 1 relative to the increase in wavelength (nm).

[0139] When the thickness of the intermediate film is greater than 0 mm and less than 1.5 mm, the optical path length L is 1 mm. When the thickness of the intermediate film is greater than 1.5 mm and less than 2.5 mm, the optical path length L is 2 mm. When the thickness of the intermediate film is greater than 2.5 mm and less than 3.5 mm, the optical path length L is 3 mm. When the thickness of the intermediate film is greater than 3.5 mm, the optical path length L is the length of the thickness of the intermediate film (mm) after rounding to the first decimal place.

[0140] In this invention, the difference between λ1 and λ2 (λ1-λ2) is preferably less than 20 nm. A difference between λ1 and λ2 of less than 20 nm will ensure that the intermediate film is less likely to be colored, resulting in a more attractive appearance.

[0141] To further prevent the intermediate film from being colored, the difference between λ1 and λ2 is preferably less than 15 nm, more preferably less than 10 nm. The lower limit of the difference between λ1 and λ2 is not particularly limited, but 0 nm is preferred. The difference between λ1 and λ2 can be adjusted according to the type and amount of the ultraviolet absorber and ionomer resin used.

[0142] It is speculated that keeping the difference between λ1 and λ2 below a certain level can ensure that the intermediate film is unlikely to be colored.

[0143] exist Figure 1 The diagram schematically shows the transmittance curves (dashed lines) obtained from the transmittance analysis of the laminated glass with an intermediate film for calculating λ1 and the transmittance curves (solid lines) obtained from the transmittance analysis of the solution for calculating λ2.

[0144] The intermediate membrane contains ionomer resin and UV absorber, while the solution contains the same concentration of UV absorber as the intermediate membrane, but does not contain any ionomer resin.

[0145] The transmittance curve of the intermediate film (dashed line) is shifted more towards the longer wavelength side compared to the transmittance curve of the solution (solid line). This may be due to the coordination of metal ions contained in the ionomer resin in the intermediate film with the UV absorber. It is believed that such coordination of metal ions with the UV absorber leads to the coloration of the intermediate film. Therefore, it is thought that if the shift on the longer wavelength side is small, i.e., the difference between λ1 and λ2 remains below a certain value, the intermediate film is less likely to be colored.

[0146] λ1 is preferably 400 nm to 430 nm. Keeping λ1 within this range will ensure that the intermediate film is unlikely to yellow. In this respect, λ1 is more preferably 410 nm to 430 nm, and even more preferably 415 nm to 425 nm.

[0147] In the transmittance analysis of laminated glass with an interlayer, a transmittance of 10% or less at a wavelength of 380 nm is preferred. A transmittance of 10% or less at a wavelength of 380 nm results in better UV shielding performance of the interlayer. More preferably, the transmittance at a wavelength of 380 nm is 5% or less, further preferably 4.5% or less, even more preferably 4.0% or less, and still more preferably 2.0% or less. The lower limit for transmittance at a wavelength of 380 nm is 0%.

[0148] In the transmittance analysis of laminated glass with an interlayer, a transmittance of 80% or more at a wavelength of 420 nm is preferred. A transmittance of 80% or more at a wavelength of 420 nm results in higher transparency and less yellowing of the interlayer. More preferably, the transmittance at a wavelength of 820 nm is 82% or more, and even more preferably, 84% or more. The upper limit for transmittance at a wavelength of 420 nm is 100%.

[0149] In the transmittance analysis of laminated glass with an interlayer, a light transmittance of 80% or more at wavelength λ1 is preferred. More preferably, the light transmittance at wavelength λ1 is 82% or more, and even more preferably 84% or more. The upper limit of the light transmittance at wavelength λ1 is 100%.

[0150] In the transmittance analysis of solutions containing ultraviolet absorbers, a light transmittance of 80% or more at wavelength λ2 is preferred. A light transmittance of 82% or more, and even more preferably 84% or more, at wavelength λ1 is preferred. The upper limit for light transmittance at wavelength λ1 is 100%.

[0151] The following explains how λ1 and λ2 are calculated.

[0152] As determined in the transmittance analysis of laminated glass obtained by sandwiching an interlayer between two pieces of transparent glass with a thickness of 2.5 mm, λ1 is the smallest wavelength (nm) at which the increase in transmittance (%) relative to the increase in wavelength (nm) is less than 1 when the wavelength is 300~460 nm and the light transmittance is at least 10%.

[0153] Here, a range with a light transmittance of at least 10% refers to Figure 1 The range of the transmittance curve (dashed line) of the intermediate film in the medium from point P to the longer wavelength side (right side). The increase in transmittance (%) relative to the increase in wavelength (nm) corresponds to the slope of the transmittance curve (dashed line), and λ1 represents the minimum wavelength with a slope of less than 1.

[0154] λ2 is determined in a solution of ultraviolet absorber with the same concentration (mass%) as the ultraviolet absorber contained in the intermediate membrane. As determined in a transmittance analysis of the solution under the condition of optical path length L (mm), λ2 is the minimum wavelength (nm) at which the increase in transmittance (%) relative to the increase in wavelength (nm) is less than 1 when the wavelength is 300~460 nm and the light transmittance is at least 10%.

[0155] Here, a range with a light transmittance of at least 10% refers to Figure 1The range of the transmittance curve (solid line) of the solution in the medium from point Q to the longer wavelength side (right side). The increase in transmittance (%) relative to the increase in wavelength (nm) corresponds to the slope of the transmittance curve (dashed line), and λ2 represents the minimum wavelength with a slope of less than 1.

[0156] The minimum wavelength with a slope of less than 1 can be determined in the following manner.

[0157] Transmittance curves are typically obtained by scanning from short wavelengths to long wavelengths at equal intervals (e.g., 5 nm intervals) using a spectrophotometer, and then plotting the transmittance at each measurement point. The slope of the transmittance curve is calculated as (Tm-Tn) / (λm-λn), where λn (nm) and λm (nm) represent adjacent measurement points, Tn (%) represents the transmittance at λn (nm), and Tm (%) represents the transmittance at λm (nm). Thus, the slope is calculated sequentially from the short wavelength side to the long wavelength side, identifying the first point where the slope falls below 1. If the slope at points λn (nm) and λm (nm) first falls below 1, the wavelength of the midpoint between λn (nm) and λm (nm) is designated as λ1 or λ2.

[0158] The solution used to determine λ2 can be prepared by dissolving the UV absorber in a solvent. There are no particular limitations on the solvent, as long as it can dissolve the UV absorber; various organic solvents and plasticizers can be used, but tetrahydrofuran or triethylene glycol di-2-ethylhexanoate is preferred.

[0159] The optical path length L for determining λ2 must be close to the thickness of the intermediate film. That is, when the thickness of the intermediate film is 0 mm to 1.5 mm, the optical path length L is 1 mm; when the thickness of the intermediate film is 1.5 mm to 2.5 mm, the optical path length L is 2 mm; when the thickness of the intermediate film is 2.5 mm to 3.5 mm, the optical path length L is 3 mm; and when the thickness of the intermediate film is greater than 3.5 mm, the optical path length L is the length of the intermediate film thickness after rounding to the first decimal place.

[0160] The optical path length L can be adjusted according to the type of unit introduced into the solution when λ2 is determined.

[0161] Yellowness Index (YI)

[0162] For a more attractive appearance, the yellowness index (YI) of the intermediate film of the present invention is preferably 2.5 or less, more preferably 2 or less, and even more preferably 1.5 or less.

[0163] For a more attractive appearance, the yellowness index (YI / d) per unit thickness of the interlayer film of the present invention is preferably 2.5 or less, more preferably 2 or less, and even more preferably 1.5 or less. The yellowness index (YI / d) per unit thickness of the interlayer film is a value obtained by dividing the yellowness index (YI) by the thickness (mm) of the interlayer film.

[0164] The yellowness index (YI) is determined using a spectrophotometer in accordance with JIS K7105.

[0165] (thickness)

[0166] The thickness of the interlayer is not particularly limited, but is preferably 0.1 mm or more, more preferably 0.2 mm or more, even more preferably 0.5 mm or more, still more preferably 0.6 mm or more, and preferably 4 mm or less, more preferably 3.0 mm or less, even more preferably 2.5 mm or less, still more preferably 1.6 mm or less, and still more preferably 1.0 mm or less. When the interlayer is used in laminated glass, having a thickness at least at the lower limit can, for example, ensure better interlayer rigidity, adhesion, and penetration resistance. Having a thickness no greater than the upper limit will make it easier to ensure the transparency of the interlayer.

[0167] (width)

[0168] The interlayer of the present invention preferably has a width of at least 1 m. A width of at least 1 m will, for example, be suitable for large laminated glass or laminated glass used in building structures. Although a width of more than 1 m makes mass production in industry more difficult, for example, containing resins other than ionomer resins, such as ethylene-methacrylic acid copolymers, in the interlayer will make mass production more controllable. A width of at least 2 m is more preferred. For better productivity, the width of the interlayer is not particularly limited, but is preferably 5 m or less, more preferably 4 m or less.

[0169] The intermediate film of the present invention is also preferably an extruded product obtained by extrusion molding as described later. The extruded product will make it easier to use for large intermediate films with a width of at least 1 m as described above, thereby facilitating mass production for industrial purposes. Although the increased viscosity of the extruded product may lead to a decrease in productivity, for example, containing resins other than ionomer resins, such as ethylene-methacrylic acid copolymers, in the intermediate film can result in better productivity.

[0170] The intermediate membrane of the present invention preferably comprises a monolayer membrane. The layer forming the monolayer membrane may comprise a resin composition having the above-described composition. That is, the layer forming the monolayer membrane preferably contains an ionomer resin and an ultraviolet absorber, and a resin composition containing optional additives as needed.

[0171] The interlayer of the present invention can also be a multilayer film having two or more layers. In the multilayer film, the overall composition of the interlayer film should be as described above, but the resin composition forming each layer should preferably have the composition of the interlayer film as described above. That is, the layers forming the multilayer film should preferably contain a resin composition containing an ionomer resin and an ultraviolet absorber, and optionally, additives as needed. The compositions of the layers of the multilayer film can be the same or different from each other.

[0172] In single-layer or multi-layer films, the content of ionomer resin, ultraviolet absorber, other resin components, and additives in the resin composition forming each layer should be as described above. However, the basis for the content of each component as described above is 100% by mass of the intermediate film, but in the resin composition forming each layer, the basis for the content of each component is 100% by mass of the resin composition, not 100% by mass of the intermediate film.

[0173] [Method for manufacturing intermediate membrane]

[0174] To form an intermediate film, a resin composition for forming the intermediate film should be obtained, and the intermediate film should be formed from the resin composition. Where necessary, the components forming the intermediate film, such as ionomer resins, ultraviolet absorbers, and additives other than ultraviolet absorbers, should be mixed to obtain a resin composition, and the obtained resin composition should be formed into a film by extrusion molding, stamping, or roll forming to obtain the intermediate film. The method of mixing the components to obtain the resin composition is not particularly limited, but a method of mixing the components using an extruder is preferred.

[0175] When the intermediate film consists of multiple layers, a resin composition for forming each layer should be prepared, and the resulting resin composition should be formed into a film by, for example, extrusion molding, stamping molding, or roll forming to form each layer. The layers are then stacked to obtain the intermediate film. In this case, extrusion molding can be performed by co-extrusion.

[0176] The intermediate film is preferably formed by extrusion molding in the above process. Extrusion molding can efficiently produce wide intermediate films.

[0177] In one embodiment, the intermediate film of the present invention can be manufactured using a so-called masterbatch. The masterbatch is a mixture (hereinafter, sometimes referred to as mixture (A)) formed by mixing additives with resin components, wherein an ionomer resin and at least one resin component other than the ionomer resin can be used as the resin component. The resin component other than the aforementioned ionomer resin is preferably one of the other resin components described above, more preferably an ethylene / (meth)acrylic acid copolymer. Using a masterbatch allows for easy mixing of the additives and the ionomer resin. The presence of other resin components as described above, such as an ethylene-(meth)acrylic acid copolymer, in mixture (A) effectively reduces the viscosity of the resin composition, thereby enabling easy compounding of the resin composition, for example, in an extruder.

[0178] The additives contained in mixture (A) preferably include ultraviolet absorbers, and may include silane coupling agents or other additives.

[0179] The form of the mixture (A) is not particularly limited, but it is usually in particulate form, such as particles.

[0180] When using a masterbatch, the intermediate film is preferably formed by extrusion molding. Therefore, in a preferred embodiment, the method for manufacturing the intermediate film may include: step (1) of compounding a mixture (A) of an ionomer resin, an ultraviolet absorber and an ethylene-(meth)acrylic acid copolymer to obtain a resin composition; and step (2) of extruding the obtained resin composition.

[0181] In step (1), the mixing ratio of mixture (A) to ionomer resin (mixture (A) / ionomer resin) by mass is preferably 2 / 98 to 30 / 70, more preferably 3 / 97 to 20 / 70, and even more preferably 4 / 96 to 15 / 85. Mixing ratios within the above range allow additives and other resin components, such as ethylene-(meth)acrylic acid copolymers, to be blended in appropriate amounts in the resin composition.

[0182] The total content of additives in mixture (A) is based on the total amount of mixture (A), preferably from 1% to 20% by mass, more preferably from 2% to 15% by mass.

[0183] Ensuring that the total amount of additives in mixture (A) is at least the lower limit mentioned above will ensure that an appropriate amount of additives are blended with the resin composition, while preventing excessive mixing of other resin components, such as ethylene-(meth)acrylic acid copolymers, unnecessarily with the resin composition. Ensuring that the amount of additives in mixture (A) is not greater than the upper limit mentioned above will ensure that the additives are properly dispersed in mixture (A).

[0184] The interlayer film of the present invention is preferably disposed between a pair of substrates and used, more preferably in a laminate as described below. The interlayer film should also be used to bond the pair of substrates. The interlayer film is particularly preferred for use in laminated glass.

[0185] Intermediate films can be used in applications beyond laminates, such as in various sealing materials, specifically in sealing materials for photovoltaic solar cells.

[0186] <Resin Composition>

[0187] The present invention provides a resin composition comprising an ionomer resin and a UV absorber, wherein the UV absorber is at least one selected from compounds having a benzotriazole structure represented by formula (I) above and compounds having a triazine structure. The resin composition is also preferably obtained by compounding a mixture of the ionomer resin, the UV absorber, and an ethylene-(meth)acrylic acid copolymer. The intermediate film obtained from this resin composition has UV-blocking properties and is less likely to be colored.

[0188] As needed, the resin composition may also contain other resin components and additives other than ultraviolet absorbers. The content of ionomer resin, ultraviolet absorber, other resin components, and additives in the resin composition are as described above. However, the basis for the content of each component mentioned above is 100% by mass of the intermediate film, but in the resin composition, the basis for the content of each component is 100% by mass of the resin composition, not 100% by mass of the intermediate film.

[0189] <Layered Body>

[0190] The laminate according to the invention includes the aforementioned interlayer and a pair of substrates, wherein the interlayer is disposed between the pair of substrates. The pair of substrates in the laminate should be bonded together by the interlayer. One or more interlayers may be disposed between a pair of glass substrates in the laminate. The multiple interlayers should be integrated between the substrates such that the pair of substrates are bonded together by the integrated multiple interlayers.

[0191] When used in building structures, the interlayer membrane disposed between the substrates in the laminate needs to be thick, for example, and using multiple interlayer membranes will make the interlayer membrane disposed between the substrates in the laminate relatively thicker.

[0192] The pair of substrates used in the laminate of the present invention are preferably selected from an organic material substrate and an inorganic material substrate.

[0193] Examples of organic material substrates include organic resin sheets and resin films. Resin films used as substrates are hereinafter referred to as substrate resin films. Organic resin sheets are also known as plexiglass sheets. Examples of organic resin sheets are not particularly limited and include polycarbonate sheets, (meth)acrylic sheets such as polymethyl methacrylate sheets, acrylonitrile-styrene copolymer sheets, acrylonitrile-butadiene-styrene copolymer sheets, polyester sheets such as polyethylene terephthalate sheets, fluoropolymer sheets, polyvinyl chloride sheets, chlorinated polyvinyl chloride sheets, polypropylene sheets, polystyrene sheets, polysulfone sheets, epoxy resin sheets, phenolic resin sheets, unsaturated polyester resin sheets, polyimide resin sheets, and other plexiglass sheets. Organic resin sheets may, for example, undergo suitable surface treatments.

[0194] In the above examples, polycarbonate sheets are preferred due to their excellent transparency and impact resistance, and (meth)acrylic sheets are preferred due to their high transparency and excellent weather resistance and mechanical strength, with polycarbonate sheets being more preferred.

[0195] The thickness of the organic resin board is not particularly limited, but it is preferably 0.1 mm or more, more preferably 0.4 mm or more, even more preferably 5.0 mm or less, and more preferably 3.0 mm or less.

[0196] The resin film used as the substrate is not particularly limited, and includes polyester resin films such as (meth)acrylic resin films, polycarbonate films, polyethylene terephthalate (PET) films, and polyethylene naphthalate (PEN) films; polyolefin resin films such as polyethylene films and polypropylene films; and cyclic polyolefin (COP) films, triacetyl cellulose (TAC) films, polyethersulfone (PES) resin films, and polyimide resin films. PET films are preferred among these. A surface layer consisting of a hard coating, for example, composed of (meth)acrylic resins, may also be provided on the surface of the resin film used as the substrate.

[0197] The resin film used as the substrate can be composed of a single layer or can be stacked in two or more layers.

[0198] The organic material substrate can also be a functional film containing a resin film for the aforementioned substrate. Polarizing films (polarizers) are preferred as examples of functional films.

[0199] The thickness of the resin film or functional film used as the substrate in the laminate is not particularly limited, but it is preferably 30 μm or more, more preferably 50 μm or more, even more preferably 500 μm or less, and more preferably 450 μm or less.

[0200] Although there is no clear distinction between them, organic resin boards are relatively thick, less flexible, and generally cannot be bent, while resin films are relatively thin and can generally be bent.

[0201] Of the above, the organic material substrate is preferably any one of polarizing film (polarizer), PET film, (meth)acrylic board and polycarbonate board.

[0202] Examples of inorganic material substrates include inorganic glass sheets. Inorganic glass sheets are not particularly limited, and examples include clear glass, clear float glass, float glass sheets, tempered glass, tinted glass, polished glass sheets, patterned glass, wire-reinforced glass sheets, wire-inserted glass sheets, ultraviolet glass sheets, infrared reflective glass sheets, infrared absorbing glass sheets, green glass, and other glass sheets. Inorganic glass can, for example, undergo surface treatment. The thickness of inorganic glass is not particularly limited, but is preferably 0.1 mm or more, more preferably 0.3 mm or more, further preferably 0.5 mm or more, even more preferably 5.0 mm or less, and more preferably 3.0 mm or less.

[0203] Here, both substrates are preferably glass. In this case, the laminate becomes a laminated glass. That is, the laminated glass of the present invention comprises a pair of glass substrates and an interlayer disposed between the pair of glass substrates. The glass substrates can be inorganic glass sheets or plexiglass sheets. The two glass substrates can be composed of the same or different materials. For example, one can be composed of inorganic glass and the other can be composed of plexiglass, but preferably both glass substrates are composed of inorganic glass or plexiglass.

[0204] The thickness of the glass substrate is not particularly limited, but is preferably 0.5 mm to 5 mm, more preferably 0.7 mm to 3 mm.

[0205] As described above, one or more interlayer films can be configured between a pair of glass substrates.

[0206] Organic or inorganic material substrates may be appropriately fitted with, for example, electrodes or sensors. The electrodes are composed of conductive layers stacked on the aforementioned substrates.

[0207] Examples of sensors include touch sensors. A touch sensor is a sensor that detects touch input when a finger, stylus, or other object approaches or contacts a substrate. It consists of a conductive layer laminated on the substrate. When a finger, stylus, or other object approaches or contacts the substrate, electrical changes, such as capacitance, current, or voltage, are generated in the conductive layer, causing the touch sensor to detect touch input based on these electrical changes.

[0208] The conductive layer is not particularly limited and any known transparent electrode material can be used, such as indium tin oxide (ITO) conductive film, tin oxide conductive film, zinc oxide conductive film and polymer conductive film.

[0209] Organic material substrates (especially films) with stacked conductive layers, such as electrodes or sensors, can form the aforementioned hard coating on the surface opposite to the surface where the conductive layer is formed.

[0210] Laminates can also be used to manufacture displays. For example, a laminate containing a display element, an interlayer film, and a surface protector can be manufactured as a display. Furthermore, a touch panel can be incorporated into the display to create a display with a touch panel. An example of a touch panel display is a laminate consisting of a display element, an interlayer film, a touch panel, another interlayer film, and a surface protector. The components are bonded and joined together via the interlayer film.

[0211] The surface protection panel is preferably either an organic resin panel or an inorganic glass panel, with inorganic glass being preferred. The surface protection panel can be an OGS (one glass solution) panel, which may incorporate sensors, such as touch sensors. Therefore, the surface protection panel can be constructed from, for example, an inorganic glass panel with integrated sensors.

[0212] Examples of display elements include organic EL display elements and liquid crystal display elements. Display elements preferably have polarizers (polarizing films) on their surfaces. Polarizers (polarizing films) typically have a structure in which protective films, such as polyvinyl alcohol resin films, are disposed on both sides of the polarizer. The protective films are made of resin films used as substrates, preferably any one of PET film, COP film, or TAC film. Alternatively, a hard coating containing, for example, (meth)acrylic resin can be disposed on the surface of the protective film as a surface layer of the substrate.

[0213] The touch panel may include any one of inorganic glass, organic resin board or resin film for substrate with touch sensor, but inorganic glass or resin film for substrate with touch sensor is preferred.

[0214] In a touch panel, two or more layers of inorganic glass, organic resin board, or substrate resin film can be laminated into a multi-layer structure. In this case, a touch sensor can be attached to any one of the inorganic glass, organic resin board, or substrate resin film in the touch panel. A protective film containing the substrate resin film can also be disposed on either the outermost surface of the front side or the outermost surface of the back side of the touch panel. Therefore, the surface where the touch panel is bonded to the intermediate film is inorganic glass, organic glass, or substrate resin film.

[0215] Photovoltaic solar cells can also be fabricated using laminates. Examples of photovoltaic solar cells incorporating laminates include photovoltaic solar cells in which power generation units are disposed within the laminate. The power generation units are disposed on the front or side of the laminate and have the function of converting light into electricity.

[0216] Specific examples of power generation units include: those using silicon-based semiconductors, such as monocrystalline silicon, polycrystalline silicon, and amorphous silicon, in the power generation unit of the photoelectric conversion layer; those using compound semiconductors, such as CuInSe-based, Cu(In,Ga)Se-based, Ag(In,Ga)Se-based, CuInS-based, Cu(In,Ga)S-based, Ag(In,Ga)S-based compounds or their solid solutions, CIS-based, CIGS-based, GaAs-based, and CdTe-based compounds, in the power generation unit of the photoelectric conversion layer; and those using organic materials, such as organic dyes, in the power generation unit of the photoelectric conversion layer.

[0217] (Manufacturing methods of laminated bodies and laminated glass)

[0218] The laminate of the present invention can be manufactured, for example, by preparing a pair of substrates and one or more intermediate films, placing one or more intermediate films between the pair of substrates, and bonding them together under pressure.

[0219] Pressure bonding is not particularly limited, but heated pressure bonding is preferred. Pre-bonding can be performed at lower pressures and temperatures, followed by formal bonding at higher pressures and / or temperatures. When multiple interlayers are disposed between a pair of substrates, the multiple interlayers should be integrated during pressure bonding.

[0220] Additionally, when the laminate is laminated glass, for example, one or more interlayer films are sandwiched between two glass substrates, and the air remaining between the two glass substrates and the interlayer films is degassed by using extrusion rollers or by vacuum suction in a rubber bag. Then, pre-bonding is performed at approximately 70-110°C to obtain a laminated intermediate. Next, the laminated intermediate should be placed in an autoclave or stamped to perform pressure bonding at approximately 120-150°C and 1-1.5 MPa to achieve final bonding. This yields laminated glass. Furthermore, when multiple interlayer films are disposed between a pair of glass substrates, it is preferable to integrate the multiple interlayer films during both pre-bonding and final bonding.

[0221] The interlayer, laminate, and laminated glass of this invention can be used in a variety of fields, including electronic devices such as displays; photovoltaic solar cells and sealing materials for photovoltaic solar cells; transportation vehicles such as automobiles, railway vehicles, aircraft, and ships; and various building structures such as buildings, apartments, detached houses, halls, and stadiums. They are preferably used in transportation vehicles and building structures, and more preferably in building structures.

[0222] Laminated glass is preferred for use in vehicles and building structures. In vehicle applications, it is preferred to use it as window glass, such as in automobiles, preferably any one of the windshield, rear window, and side window glass.

[0223] In building structures, they are preferably used as, for example, window glass, glass floors, or curtain walls. When used in building structures, laminated glass can be, for example, large in size and used as structural glass. Example

[0224] The invention has been described in more detail through examples, but the invention is not limited by these examples.

[0225] The various physical properties were determined and evaluated as follows.

[0226] [Thickness of the interlayer]

[0227] The average thickness of the intermediate film was measured at 10 points using a microscope manufactured by Olympus, called DSX500.

[0228] [Content and neutralization degree of each structural unit]

[0229] The mass percentage of each structural unit of ethylene-(meth)acrylic acid copolymers and their ionomer resins, after the following hydrochloric acid treatment, is determined by... 1 Determined by H-NMR and IR analysis.

[0230] [Hydrochloric acid treatment]

[0231] Add 500 μL of ethanol and 1 mL of hydrochloric acid to 100 mg of the sample, which has been cryogenically pulverized using a JFC-2000 (manufactured by Japan Analytical Industries Co., Ltd.), and stir at 60°C for 48 hours. Afterward, wash three times with ultrapure water to remove hydrochloric acid, and then dry by heating.

[0232] [Neutralization degree]

[0233] The degree of neutralization was determined by performing IR analysis on samples before and after hydrochloric acid treatment. The IR values ​​were measured at 1460 cm⁻¹ before and after hydrochloric acid treatment. -1 Based on the peak height of the methylene group, according to 1700 cm⁻¹ -1 The carboxylic acid peak height was used to calculate the degree of neutralization using the following formula. In the following formula, the denominator is 1700 cm⁻¹ in the hydrochloric acid-treated sample. -1 Peak height / 1460cm -1 The peak height of the molecule is 1700 cm⁻¹ in the sample before hydrochloric acid treatment. -1 Peak height / 1460cm -1 The peak height.

[0234] [Formula 1]

[0235] Degree of neutralization = 100×

[0236] [1 [H-NMR analysis]

[0237] The hydrochloric acid-treated sample was dissolved in a solvent (tetrachloroethane: dimethyl sulfoxide = 5: 2) at a concentration of approximately 1–3% by mass to prepare an analytical solution. The solution was then used... 1 1H-NMR analysis (Apparatus: AVANCE 400 (PRODIGY), spectrometer: AVANCE III HD). Analysis conditions were 8 cycles, temperature 120°C. The integral value of the H from the methyl group derived from methacrylic acid was set as the baseline, and this value was 3.00. The total mass percentage of structural units (A) and (B) and the mass percentage of structural unit (C) derived from ethylene were calculated based on the integral intensity ratio of the H peaks derived from methylene groups in the range of 1.15–1.62 ppm. The individual contents of structural units (A) and (B) were also calculated based on the aforementioned neutralization degree.

[0238] Yellowness Index (YI)

[0239] The yellowness index (YI) values ​​of the laminated glass obtained in the examples were analyzed using a spectrophotometer (Hitachi High-Tech U-4100) following the transmission method of JIS K7105.

[0240] [λ1-λ2]

[0241] (1) Preparation of laminated glass

[0242] Two pieces of transparent glass (5 cm long × 5 cm wide × 2.5 mm thick, with a visible light transmittance of 90.4%, manufactured by Central Glass Co., Ltd.) and a 5 cm × 5 cm interlayer film prepared in the various examples and comparative examples were prepared according to JIS R3202 (2011). The interlayer film was sandwiched between the two pieces of transparent glass to obtain a laminate. The laminate was placed in a rubber bag and degassed at a vacuum of 0.08 MPa for 20 minutes. After degassed, it was transferred to an oven and vacuum-pressed at 90°C for 30 minutes to pre-press the laminate. In an autoclave, the pre-pressed laminate was pressure-bonded at 140°C and 1.3 MPa for 20 minutes to obtain a laminated glass with a glass plate / interlayer / glass plate structure.

[0243] (2) λ1 (nm) analysis

[0244] The transmittance in the wavelength range of 300–460 nm was determined by analyzing the laminated glass prepared as described above using a spectrophotometer (“U-4100” manufactured by Hitachi High-Tech).

[0245] The minimum wavelength λ1 (nm) is determined to be less than 1 for the increase in transmittance (%) relative to the increase in wavelength (nm) within a range where the transmittance is at least 10%.

[0246] Specifically, within a range where light transmittance is above 10%, the slope (increase in transmittance / increase in wavelength) between the shorter wavelength side and adjacent measurement points is calculated sequentially to determine the point where the slope first falls below 1. λ1 (nm) is the wavelength at the midpoint between λn (nm) and λm (nm), where λn (nm) and λm (nm) represent adjacent measurement points to the point where the slope first falls below 1.

[0247] (3) λ2 (nm) analysis

[0248] Solutions of the ultraviolet absorbers used in the various embodiments and comparative examples were prepared, wherein the concentration of the ultraviolet absorber was the same as the concentration in the intermediate membrane. Specifically, solutions were prepared by dissolving the ultraviolet absorber in either THF or triethylene glycol bis(2-ethylhexanoate) (3GO).

[0249] The solution prepared above was added to a unit with an optical path length of 1 mm, and the transmittance in the wavelength range of 300~460 nm was determined using a spectrophotometer (Hitachi High-tech "U-4100").

[0250] The minimum wavelength λ2 (nm) is determined to be less than 1 for the increase in transmittance (%) relative to the increase in wavelength (nm) within a range where the transmittance is at least 10%.

[0251] Specifically, within a range where light transmittance is above 10%, the slope (increase in transmittance / increase in wavelength) between the shorter wavelength side and adjacent measurement points is calculated sequentially to determine the point where the slope first falls below 1. λ2 (nm) is the wavelength at the midpoint between λn (nm) and λm (nm), where λn (nm) and λm (nm) represent adjacent measurement points to the point where the slope first falls below 1.

[0252] [Transmittance at wavelengths of 380 nm and 420 nm]

[0253] Two pieces of transparent glass (5 cm long × 5 cm wide × 2.5 mm thick, with a visible light transmittance of 90.4%, manufactured by Central Glass Co., Ltd.) and a 5 cm × 5 cm interlayer film prepared in the various examples and comparative examples were prepared according to JIS R3202 (2011). The interlayer film was sandwiched between the two pieces of transparent glass to obtain a laminate. The laminate was placed in a rubber bag and degassed at a vacuum of 0.08 MPa for 20 minutes. While still degassed, it was transferred to an oven and vacuum-pressed at 90°C for 30 minutes to pre-press the laminate. In an autoclave, the pre-pressed laminate was pressure-bonded at 140°C and 1.3 MPa for 20 minutes to obtain a laminated glass with a glass plate / interlayer / glass plate structure.

[0254] The laminated glass prepared as described above was analyzed using a spectrophotometer (Hitachi High-Tech U-4100) to determine the transmittance at a wavelength of 380 nm (T380) and at a wavelength of 420 nm (T420).

[0255] [Evaluation of Yellowing Inhibition]

[0256] The intermediate films prepared in each embodiment and comparative example were used as samples. The samples were fixed to a base cut at a 5 cm angle and kept upright. The ends of the samples were viewed from the front, and 10 evaluators evaluated the yellowness index compared with a color chart (yellowness index: 0.5).

[0257] The degree of inhibition of yellowing was evaluated according to the following criteria.

[0258] A: Less than 3 out of 10 people rated it as more yellow than the color chart.

[0259] B: 4-5 out of 10 people rated it as more yellow than the color chart suggests.

[0260] C: More than 6 out of 10 people rated it as more yellow than the color chart.

[0261] [Evaluation of Adhesion]

[0262] (Preparation of laminated glass)

[0263] The intermediate membranes of Examples 5-7 described later were subjected to a pummel test.

[0264] The intermediate films of Examples 5-7 are sandwiched between two pieces of transparent glass (300 mm long × 300 mm wide) with a thickness of 2.5 mm in accordance with JIS R3202 (2011) to obtain a laminate.

[0265] Prepare a laminate of a top surface sandwich layer stacked in a manner where the top surface is in contact with the intermediate membrane and a laminate of a bottom surface sandwich layer stacked in a manner where the bottom surface is in contact with the intermediate membrane.

[0266] The laminate was placed in a rubber bag and degassed under a vacuum of 0.08 MPa for 20 minutes. While still degassed, it was transferred to an oven and vacuum-pressed at 90°C for 30 minutes to pre-press the laminate. In an autoclave, the pre-pressed laminate was pressure-bonded at 140°C and 1.3 MPa for 20 minutes to obtain a laminated glass comprising a glass plate / interlayer / glass plate structure.

[0267] (Tapping test)

[0268] The resulting laminated glass was left to stand at 23°C ± 0.6°C for 16 hours. The central portion (150 mm long × 150 mm wide) of the stood laminated glass was then struck with a hammer with a head of 0.45 kg, pulverizing it until the glass particle size was less than 6 mm. The other side was struck the same number of times. The degree of film exposure after partial glass peeling was determined using the impact values ​​specified in Table 1 below. Each embodiment was analyzed using two pieces of laminated glass, and the arithmetic mean of the four impact values ​​from the front and back sides was calculated.

[0269] The tapping value refers to the degree of adhesion between the interlayer film and the glass plate. It is determined based on the degree of film exposure after partial glass peeling, and is defined in Table 1. The higher the tapping value, the stronger the adhesion of the interlayer film.

[0270] [Table 1]

[0271] Table 1

[0272]

[0273] The components used in the examples and comparative examples are as follows.

[0274] <Ionomer Resins>

[0275] The details of ionomer resins are as follows.

[0276] [Table 2]

[0277] Table 2

[0278]

[0279] ※Ionomer resin 1 is an ionomer resin formed by neutralizing ethylene-methacrylic acid copolymers with magnesium ions.

[0280] <UV absorber>

[0281] Compounds having a benzotriazole structure represented by formula (I): “RIASORB UV-234” manufactured by Rianlon, and compounds represented by formula (2), shown as “UV-234” in Table 3.

[0282] Compounds having a benzotriazole structure represented by formula (I): "Tinuvin 640" manufactured by BASF, and compounds represented by formula (3), shown as "UV-640" in Table 3.

[0283] Compounds with a triazine structure: “UV-1164” manufactured by Rianlon, 2-[4,6-bis(2,4-dimethylphenyl)-1,3,5-triazin-2-yl]-5-(octyloxy)phenol, shown as “UV-1164” in Table 3.

[0284] Benzophenone-based UV absorbers, such as "SEESORB 107" manufactured by Shipro Kasei.

[0285] Compounds with a benzotriazole structure that does not correspond to formula (I): "Tinuvin-P" manufactured by BASF.

[0286] [Example 1]

[0287] (Preparation of the intermediate membrane)

[0288] An intermediate film with a thickness of 1000 μm and the composition shown in Table 3 was obtained by mixing 100 parts by weight of ionomer resin 1 and 0.3 parts by weight of UV absorber at 170°C and then extruding. The properties of the intermediate film were evaluated.

[0289] [Examples 2-4, Comparative Examples 1-3]

[0290] Except for the changes in the composition of the intermediate membrane as shown in Table 3, the intermediate membrane was prepared in the same manner as in Example 1. The properties of the intermediate membrane were evaluated.

[0291] [Example 5]

[0292] Except for changing the type of ultraviolet absorber to 0.2 parts by mass as shown in Table 4 and changing the thickness of the intermediate film to 760 μm, the intermediate film was prepared in the same manner as in Example 1. The properties of the intermediate film were evaluated.

[0293] [Example 6]

[0294] The intermediate membrane was prepared in the same manner as in Example 5, except that 0.1% by mass of 3-epoxypropoxypropylmethyldimethoxysilane (manufactured by Shin-Etsu Silicon Co., Ltd., trade name: KBE-402) was added as a silane coupling agent at a rate of 100% by mass of the entire intermediate membrane. The properties of this intermediate membrane were evaluated.

[0295] [Example 7]

[0296] The intermediate membrane was prepared in the same manner as in Example 5, except that 0.1% by mass of N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane (manufactured by Shin-Etsu Silicon Co., Ltd., trade name: KBM-602) was added as a silane coupling agent at a total weight of 100% of the intermediate membrane. The properties of this intermediate membrane were evaluated.

[0297] Table 4 shows the results of Examples 5-7.

[0298] [Table 3]

[0299] Table 3

[0300]

[0301] [Table 4]

[0302] Table 4

[0303]

[0304] The intermediate film in each embodiment contains an ultraviolet absorber with a low T380 (%) value and good ultraviolet blocking performance. The intermediate film also contains an ionomer resin with a low yellowness index (YI) and is not significantly colored.

[0305] The results of Examples 5-7 show that the intermediate film in which the silane coupling agent is added to the ionomer resin can provide excellent adhesion on any glass surface.

[0306] The intermediate film of Comparative Example 1 does not contain ultraviolet absorbers, has a low yellowness index, but a high T380 (%) value, and has poor ultraviolet shielding performance.

[0307] The results showed that the intermediate films of Comparative Examples 2-3 did not use the specific ultraviolet absorber of the present invention, had a high yellowness index (YI), and were easier to color than the intermediate films of the Examples.

Claims

1. An intermediate film containing an ionomer resin and an ultraviolet absorber, wherein, The ultraviolet absorber is selected from at least one compound having a benzotriazole structure represented by the following formula (I) and a triazine structure: [Chemical Formula 1] In the above formula, R1 is an organic group with 4 or more carbon atoms, and R2 to R8 are each an independent hydrogen atom, halogen atom, or organic group with 1 to 20 carbon atoms.

2. The intermediate membrane according to claim 1, wherein, The compound having the benzotriazole structure is any one of the compounds represented by the following formulas (2) to (4). [Chemical Formula 2] 。 3. The intermediate membrane according to claim 1 or 2, wherein, The content of the ultraviolet absorber is 0.01 to 1 part by mass relative to 100 parts by mass of ionomer resin.

4. The intermediate membrane according to claim 1 or 2, wherein, The ionomer resin contains at least one of magnesium and zinc.

5. The intermediate membrane according to claim 1 or 2, wherein, The intermediate membrane contains a silane coupling agent.

6. The intermediate membrane according to claim 5, wherein, The silane coupling agent is a silane coupling agent with an epoxy group.

7. The intermediate membrane according to claim 5, wherein, The intermediate membrane comprises 0.01% to 0.5% by mass of silane coupling agent, with the total weight of the intermediate membrane being 100%.

8. A laminate comprising an intermediate film as described in claim 1 or 2 and a pair of substrates, wherein the intermediate film is disposed between the pair of substrates.

9. The laminate according to claim 8, wherein, The laminated body is laminated glass.

10. The laminate according to claim 8, wherein, The laminated body is laminated glass used in building structures.

11. A method for manufacturing an intermediate film according to claim 1 or 2, comprising: The step of compounding a mixture of ionomer resin, ultraviolet absorber and ethylene-(meth)acrylic acid copolymer to obtain a resin composition; as well as The step of extruding the resin composition.

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