Resin substrate with anti-fogging film, transparent article with anti-fogging film, and coating liquid

Abstract

A novel resin substrate with an anti-fogging film is provided. [Solution] The anti-fogging film-attached resin substrate comprises a resin substrate and an anti-fogging film on its surface, the anti-fogging film comprising a silane coupling agent and / or a crosslinked structure derived therefrom, a water-absorbent polymer, a polyether-modified siloxane, and a diol having 2 to 8 carbon atoms. The silane coupling agents include silane coupling agent A and silane coupling agent B and / or silane coupling agent C. Silane coupling agent A has an amino group, a silicon atom, and a hydrocarbon group having 1 to 3 carbon atoms bonded to the amino group and the silicon atom. Silane coupling agent B has an amino group, a silicon atom, and a hydrocarbon group having 4 or more carbon atoms bonded to the amino group and the silicon atom. Silane coupling agent C is a polymer having multiple amino groups.

Description

[Technical Field]

[0001] The present invention relates to a resin substrate with an anti-fogging film, an article containing the anti-fogging film, and a coating liquid for forming the anti-fogging film. An article containing the anti-fogging film is, for example, a transparent article with an anti-fogging film. [Background technology]

[0002] Anti-fog sheets are being developed to provide anti-fogging properties. Anti-fog sheets are placed in or near areas where anti-fogging is required, and more specifically, are used by being attached to them. An anti-fog sheet comprises a resin substrate and an anti-fog film on the surface of the resin substrate. In some cases, the anti-fog sheet may have an adhesive layer further on the surface of the resin substrate opposite to the anti-fog film, and, if necessary, a protective sheet further on the surface of the anti-fog film, thus taking the form of an anti-fog laminate. However, a resin substrate with an anti-fog film on its surface may also be used as an anti-fog article in its own state, in other words, without being attached to other components. In this specification, a resin substrate having an anti-fog film will be referred to as an "anti-fog film-coated resin substrate" regardless of its form of use.

[0003] For example, Patent Document 1 discloses an anti-fog sheet for use as a windshield in an automobile, which is attached to the interior surface of the information acquisition area through which light passes to the information acquisition device. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] International Publication No. 2018 / 016454 [Overview of the project] [Problems that the invention aims to solve]

[0005] The required anti-fogging properties of the anti-fogging film contained in the anti-fogging film of the resin substrate vary greatly depending on the location where the anti-fogging film is placed or used. Therefore, the present invention aims to provide a novel anti-fogging film-coated resin substrate. [Means for solving the problem]

[0006] Hereafter, this specification will omit any mention that QR Code is a registered trademark.

[0007] The present invention The device comprises a resin substrate and an anti-fogging film on the surface of the resin substrate, In a test in which the anti-fog film is immersed in 25°C water for 100 hours, removed from the water, exposed to water vapor generated from 90°C to 100°C water placed 60 mm vertically downward from the anti-fog film for 30 seconds, and the information of a QR code placed 110 mm downward in the same direction from the anti-fog film can be read using a camera from the side opposite to the side on which the anti-fog film is formed, the information of a QR code with a size of 40 mm square can be read. We provide a resin substrate with an anti-fogging film. Here, the QR code is a two-dimensional code that encodes the string "Rank:B" as the information, in accordance with the Japanese Industrial Standard (JIS) X 0510:2018, with a symbol size of 21x21 modules and error correction level H.

[0008] From another perspective, the present invention is The device comprises a resin substrate and an anti-fogging film on the surface of the resin substrate, The anti-fogging film comprises a water-absorbing polymer, When the anti-fog film was immersed in 25°C water for 100 hours, removed from the water, and exposed for 30 seconds to water vapor generated from 90°C to 100°C water placed 60 mm vertically below the anti-fog film, a transparent continuous film was formed on the surface of the anti-fog film exposed to the water vapor. We provide a resin substrate with an anti-fogging film.

[0009] From another perspective, the present invention is The device comprises a resin substrate and an anti-fogging film on the surface of the resin substrate, The anti-fogging film comprises at least one selected from the group consisting of a silane coupling agent and a crosslinked structure derived from a silane coupling agent, a water-absorbing polymer, a polyether-modified siloxane, and a diol having 2 to 8 carbon atoms. The silane coupling agent comprises silane coupling agent A and at least one silane coupling agent selected from the group consisting of silane coupling agent B and silane coupling agent C. The silane coupling agent A has an amino group, a silicon atom, and a hydrocarbon group having 1 to 3 carbon atoms bonded to the amino group and the silicon atom. The silane coupling agent B has an amino group, a silicon atom, and a hydrocarbon group having 4 or more carbon atoms bonded to the amino group and the silicon atom. The silane coupling agent C is a polymer having multiple amino groups. We provide a resin substrate with an anti-fogging film.

[0010] Furthermore, from another perspective, the present invention is The present invention provides a transparent article with an anti-fog film, which is equipped with a resin substrate with an anti-fog film.

[0011] Furthermore, from another perspective, the present invention is It contains a water-absorbing polymer, a polyether-modified siloxane, a diol having 2 to 8 carbon atoms, and a silane coupling agent. The silane coupling agent comprises silane coupling agent A and at least one silane coupling agent selected from the group consisting of silane coupling agent B and silane coupling agent C. The silane coupling agent A has an amino group, a silicon atom, and a hydrocarbon group having 1 to 3 carbon atoms bonded to the amino group and the silicon atom. The silane coupling agent B has an amino group, a silicon atom, and a hydrocarbon group having 4 or more carbon atoms bonded to the amino group and the silicon atom. The silane coupling agent C is a polymer having a plurality of amino groups. A coating solution is provided.

Advantages of the Invention

[0012] According to the present invention, a novel resin substrate with an anti-fogging film is provided.

Brief Description of the Drawings

[0013] [Figure 1] It is a cross-sectional view showing an example of a laminate (anti-fogging sheet) including a resin substrate with an anti-fogging film according to the present embodiment. [Figure 2] It is a cross-sectional view showing another example of a laminate (anti-fogging sheet) including a resin substrate with an anti-fogging film according to the present embodiment. [Figure 3A] It is a schematic diagram for explaining the outline of the high-temperature steam evaluation. [Figure 3B] It is another schematic diagram for explaining the outline of the high-temperature steam evaluation. [Figure 4A] It is an example of a QR code used in the high-temperature steam evaluation (size 10 mm × 10 mm, recorded information "Rank: SSS"). [Figure 4B] It is an example of a QR code used in the high-temperature steam evaluation (size 15 mm × 15 mm, recorded information "Rank: SS"). [Figure 4C] It is an example of a QR code used in the high-temperature steam evaluation (size 20 mm × 20 mm, recorded information "Rank: S"). [Figure 4D] It is an example of a QR code used in the high-temperature steam evaluation (size 30 mm × 30 mm, recorded information "Rank: A"). [Figure 4E] It is an example of a QR code used in the high-temperature steam evaluation (size 40 mm × 40 mm, recorded information "Rank: B").

Modes for Carrying Out the Invention

[0014] Embodiments of the present invention will be described below with reference to the drawings as appropriate, but the present invention is not limited to the embodiments described below. In this specification, "main component" means the component with the highest content. In the case of a plate-shaped article, "main surface" means two surfaces facing opposite directions separated by a predetermined distance called the thickness.

[0015] As disclosed in Patent Document 1, water-absorbing polymers are often incorporated into anti-fogging films. As the water-absorbing polymer content increases, the anti-fogging properties of the film can be expected to improve. On the other hand, as the water-absorbing polymer content increases, the abrasion resistance of the film usually decreases. For this reason, as disclosed in Patent Document 1, inorganic components, typically silica components such as colloidal silica, are often added to anti-fogging films to compensate for the decrease in abrasion resistance. However, anti-fogging films are sometimes required to have other properties, even if a high level of abrasion resistance is not required. For example, it may be required that the anti-fogging film maintains its anti-fogging properties even when exposed to harsh environments for a long period of time. The resin substrate with an anti-fogging film according to this embodiment was obtained by further consideration from this viewpoint, and the anti-fogging film can exhibit a function of transmitting light without scattering at a high level even when exposed to harsh environments.

[0016] In Figure 1, the resin substrate 1 with an anti-fog film comprises a base resin substrate 10 and an anti-fog film 11 on the surface of the resin substrate 10. The anti-fog film 11 is formed on at least a portion of the surface of the resin substrate 10, for example, on the main surface of the resin substrate 10. In Figure 1, the resin substrate 1 with an anti-fog film constitutes part of an anti-fog sheet 15 further comprising an adhesive layer 13, etc. However, the resin substrate 1 with an anti-fog film may be used in a form without an adhesive layer or other layers or sheets.

[0017] As shown in Figure 1, the anti-fog sheet 15 comprises an anti-fog film-coated resin substrate 1, a protective sheet 12 on the surface of the anti-fog film 11, and an adhesive layer 13 on the surface of the anti-fog film-coated resin substrate 1 opposite to the side on which the anti-fog film 11 is formed. The anti-fog sheet 15 further comprises a release sheet 14 attached to the adhesive layer 13. The protective sheet 12 and the release sheet 14 are attached in a removable manner. The protective sheet 12, the adhesive layer 13, and the release sheet 14 are convenient for the storage, transport, and fixing of the anti-fog film-coated resin substrate 1, but are not essential. For example, the anti-fog film-coated resin substrate 1 may be fixed by applying a separately prepared adhesive instead of using the adhesive layer 13. In one fixed form, the anti-fog film-coated resin substrate 1 has a configuration in which the anti-fog film 11, the resin substrate 10, and the adhesive layer 13 or an adhesive layer applied in place thereof are laminated in this order.

[0018] The anti-fog sheet 25 shown in Figure 2 comprises an anti-fog film-attached resin substrate 2 having a resin substrate 20 and an anti-fog film 21 on its surface, a protective sheet 22 on the surface of the anti-fog film 21, and an adhesive layer 23 formed on the surface of the anti-fog film-attached resin substrate 2 opposite to the side on which the anti-fog film 21 is formed. The protective sheet 22 is peelably attached to the anti-fog film 21. The anti-fog sheet 25 may also be a wound body wound so that the exposed surface of the adhesive layer 23 is in contact with the surface of the protective sheet 22. In this embodiment, the protective sheet 22 also functions as a release sheet. In Figure 2, reference numeral 23 may also indicate a back surface protective sheet. In this case, the anti-fog film-attached resin substrate 2 has protective sheets 22 and 23 on its uppermost and lowermost layers. Each layer will be described below.

[0019] [Resin substrate] The resin material constituting the resin substrates 10 and 20 is not particularly limited and includes, for example, polyolefins such as polyethylene and polypropylene, acrylic resins such as methacrylic resin (PMMA), polycarbonate (PC), acrylonitrile / styrene resin (AS), acrylonitrile / butadiene / styrene resin (ABS), cycloolefin polymer (COP), vinyl chloride (PVC), triacetylcellulose (TAC), polyesters such as polyethylene terephthalate (PET), and urethane. The thickness of the resin substrates 10 and 20 is, for example, 0.02 to 7.0 mm. The thickness of the resin substrate may be 0.1 to 7.0 mm, more preferably 0.2 to 7.0 mm, and in some cases 3.0 to 5.0 mm. When the resin is acrylic resin, the thickness of the resin substrate is preferably 2.0 to 3.0 mm. When the resin is polycarbonate, the thickness of the resin substrate is preferably 1.0 to 2.0 mm. The resin substrate is preferably a transparent substrate. The resin substrate may be in the form of a film with a thickness of 0.02 to 0.3 mm. The resin film is suitable as a base material for anti-fogging sheets to impart anti-fogging properties to other articles. Resin substrates with a thickness exceeding 0.3 mm, which is somewhat thicker than what would typically be called a film, are suitable for applications where they are not attached to other articles.

[0020] For example, in order to ensure wettability, plasma treatment may be performed on the surface of the resin substrate to which the anti-fogging film is to be formed before the anti-fogging film is formed. Plasma treatment is a process in which the resin substrate is exposed to plasma. Plasma treatment may be performed using plasma under a reduced pressure atmosphere or using atmospheric pressure plasma. Atmospheric pressure plasma treatment may be AP plasma treatment or corona discharge treatment.

[0021] [Anti-fogging film] The film thickness of the anti-fogging films 11 and 21 is not limited to a specific value, but is 0.1 to 15 μm, preferably 0.5 to 10 μm, and particularly preferably 0.8 to 6 μm.

[0022] The anti-fogging films 11 and 21 include, for example, a water-absorbing polymer, a polyether-modified siloxane, a diol having 2 to 8 carbon atoms, a silane coupling agent and / or a crosslinked structure derived from the silane coupling agent. Each component is described below.

[0023] (Superabsorbent polymer) Examples of superabsorbent polymers include at least one selected from the group consisting of urethane resins, epoxy resins, acrylic resins, polyvinyl acetal resins, and polyvinyl alcohol resins. Examples of urethane resins include polyurethane resins composed of polyisocyanate and polyol. Examples of polyols include acrylic polyols and polyoxyalkylene polyols. Examples of epoxy resins include glycidyl ether epoxy resins, glycidyl ester epoxy resins, glycidylamine epoxy resins, and cyclic aliphatic epoxy resins. A preferred epoxy resin is a cyclic aliphatic epoxy resin. Below, polyvinyl acetal resin (hereinafter simply referred to as "polyvinyl acetal"), which is a preferred superabsorbent polymer, will be described.

[0024] Polyvinyl acetal can be obtained by condensing polyvinyl alcohol with an aldehyde to form an acetal. The acetalization of polyvinyl alcohol can be carried out using known methods such as precipitation using an aqueous medium in the presence of an acid catalyst, or dissolution using a solvent such as alcohol. Acetalization can also be carried out in parallel with the saponification of polyvinyl acetate. The degree of acetalization is preferably 2-40 mol%, more preferably 3-30 mol%, particularly 5-20 mol%, and in some cases 5-15 mol%. The degree of acetalization can be, for example, 13 It can be measured based on 1C nuclear magnetic resonance spectroscopy. Polyvinyl acetals with an acetalization degree within the above range are suitable for forming anti-fogging films with good water absorption and water resistance.

[0025] The average degree of polymerization of polyvinyl alcohol is preferably 200 to 4500, and more preferably 500 to 4500. A high average degree of polymerization is advantageous for forming an anti-fogging film with good water absorption and water resistance, but if the average degree of polymerization is too high, the viscosity of the solution may become too high, which may hinder film formation. The degree of saponification of polyvinyl alcohol is preferably 75 to 99.8 mol%.

[0026] Examples of aldehydes to be condensed with polyvinyl alcohol include aliphatic aldehydes such as formaldehyde, acetaldehyde, butyraldehyde, hexylcarbaldehyde, octylcarbaldehyde, and decylcarbaldehyde. Other examples include benzaldehyde; 2-methylbenzaldehyde, 3-methylbenzaldehyde, 4-methylbenzaldehyde, and other alkyl-substituted benzaldehydes; chlorobenzaldehyde and other halogen-substituted benzaldehydes; substituted benzaldehydes in which hydrogen atoms are substituted by functional groups other than alkyl groups such as hydroxyl, alkoxy, amino, and cyano groups; and aromatic aldehydes such as naphthaldehyde and anthraldehyde, which are condensed aromatic ring aldehydes. Aromatic aldehydes with strong hydrophobicity are advantageous in forming water-absorbing films with a low degree of acetalization and excellent water resistance. The use of aromatic aldehydes is also advantageous in forming highly absorbent films while retaining a large number of hydroxyl groups. It is preferable that the polyvinyl acetal contains an acetal structure derived from an aromatic aldehyde, particularly benzaldehyde.

[0027] The content of the water-absorbing polymer in the anti-fogging film is, for example, 20 to 90% by mass, preferably 30 to 80% by mass, and more preferably 35 to 75% by mass. The water-absorbing polymer may also be the main component of the anti-fogging film.

[0028] (Polyether-modified siloxane) A polyether-modified siloxane is a compound having a polyether chain as at least one selected from molecular chains bonded to the ends of the siloxane main chain and molecular chains bonded as side chains to the siloxane main chain. A siloxane is a compound with a siloxane bond (Si-O-Si) as its backbone. The constituent units of the polyether chain are not particularly limited, but examples include ethylene oxide and propylene oxide. The polyether chain may contain only one type of constituent unit, or it may contain two or more types.

[0029] Polyether-modified siloxane may also be polyether-modified silicone. Silicone is a polymer with a siloxane bond (Si-O-Si) backbone. An example of polyether-modified silicone is Silface SAG503A manufactured by Nisshin Chemical Industry Co., Ltd.

[0030] The content of polyether-modified siloxane in the anti-fogging film is, for example, 0.5 to 30% by mass, preferably 1 to 25% by mass, and more preferably 3 to 20% by mass.

[0031] (Diol) Diols having 2 to 8 carbon atoms, in other words, diols having 2 to 8 carbon atoms, may include, for example, at least one selected from the group consisting of ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butanediol, pentanediol, and hexanediol. The diol may also be a diol having 2 to 6 carbon atoms. Preferred diols include at least one selected from the group consisting of butanediol, propylene glycol, and dipropylene glycol. The anti-fogging film may contain propylene glycol and / or dipropylene glycol as particularly preferred diols.

[0032] The content of C2-C8 diols in the anti-fogging film is, for example, 0.01-30% by mass, preferably 0.05-20% by mass, and more preferably 0.1-10% by mass.

[0033] (Silane coupling agents and crosslinked structures derived therefrom) The silane coupling agent includes a silane coupling agent having an amino group (hereinafter sometimes referred to as "aminosilane"). The amino group may be primary, secondary, or tertiary, but primary and secondary amino groups are preferred. It is desirable that the aminosilane includes silane coupling agent A and a silane coupling agent corresponding to silane coupling agent B and / or silane coupling agent C. It is desirable that the silane coupling agent also includes silane coupling agent E in addition to aminosilane. Silane coupling agent E includes reactive functional groups other than amino groups. Each silane coupling agent will be described below.

[0034] (Silane coupling agent A) Silane coupling agent A has an amino group, a silicon atom, and a hydrocarbon group having 1 to 3 carbon atoms bonded to the amino group and the silicon atom. The hydrocarbon group may be an alkylene group. Silane coupling agent A may have one silicon atom in a single molecule. Examples of silane coupling agent A include silicon compounds having a hydrolyzable group represented by the following formula (I). Silicon compounds having a hydrolyzable group represented by formula (I) may be used alone or in combination of two or more.

[0035] H2N-L 1 -SiY 3-n X n (I)

[0036] In equation (I), n represents an integer between 1 and 3.

[0037] X is a hydrolyzable group or a halogen atom. Examples of hydrolyzable groups include at least one selected from alkoxy groups, acetoxy groups, alkenyloxy groups, and amino groups. Preferred alkoxy groups include alkoxy groups having 1 to 4 carbon atoms (methoxy group, ethoxy group, propoxy group, butoxy group). A preferred halogen atom is chlorine.

[0038] Y is an alkyl group having 1 to 3 carbon atoms. Preferred alkyl groups are methyl group and ethyl group.

[0039] L 1 is a hydrocarbon group having 1 to 3 carbon atoms, preferably an alkylene group. Examples of the hydrocarbon group include methylene group, ethylene group, n-propylene group, isopropylene group, vinylene group, and propenylene group.

[0040] The compound in which X in formula (I) is an alkoxyl group is called a silicon alkoxide. In formula (I), preferably, n is 3. That is, the silane coupling agent A is preferably a trifunctional silicon alkoxide having a reactive functional group represented by H2N-L 1 -SiX3.

[0041] Examples of the trifunctional silicon alkoxide having a reactive functional group are aminoalkyltrialkoxysilanes. Examples of aminoalkyltrialkoxysilanes are 3-aminopropyltrimethoxysilane (APTMS) and 3-aminopropyltriethoxysilane (APTES).

[0042] (Silane coupling agent B) The silane coupling agent B has an amino group, a silicon atom, and a hydrocarbon group having 4 or more, preferably 6 or more, carbon atoms bonded to the amino group and the silicon atom. The hydrocarbon group may be an alkylene group. The silane coupling agent B may contain one silicon atom in one molecule. Examples of the silane coupling agent B include silicon compounds having a hydrolyzable group represented by the following formula (II). The silicon compound having a hydrolyzable group represented by formula (II) may be used alone or in combination of two or more.

[0043] R 2 HN-L 2 -SiY 3-n X n (II)

[0044] In equation (II), n represents an integer between 1 and 3.

[0045] L 2 This is a hydrocarbon group having 4 or more carbon atoms, preferably an alkylene group. The number of carbon atoms in the hydrocarbon group is preferably 6 or more, but may be 12 or less. Examples of preferred alkylene groups include butylene, hexylene, heptylene, octylene, and dodecylene.

[0046] R 2 This is a hydrocarbon group which may have a hydrogen atom or substituents. The number of carbon atoms in this hydrocarbon group is not particularly limited, for example, 4 to 12, but may be 3 or less. The substituent may be a reactive functional group. The reactive functional group is at least one selected from, for example, an epoxy group, an amino group, a mercapto group, an isocyanate group, an acrylic group, and a methacrylic group, and is preferably an amino group.

[0047] X is a hydrolyzable group or a halogen atom. Specific examples of hydrolyzable groups and halogen atoms are as described above. Y is an alkyl group having 1 to 3 carbon atoms. Specific examples of alkyl groups having 1 to 3 carbon atoms are as described above.

[0048] A specific example of silane coupling agent B having the preferred structure described above is KBM-6803 manufactured by Shin-Etsu Silicone Co., Ltd.

[0049] (Silane coupling agent C) Silane coupling agent C is a polymer having multiple amino groups. Silane coupling agent C may also be an organic polymer type silane coupling agent. The organic polymer type silane coupling agent may have a structure in which multiple functional groups containing silicon atoms to which hydrolyzable groups are bonded, and multiple functional groups containing amino groups are bonded to the organic polymer constituting the main chain. Silane coupling agent C typically has a structure containing three or more amino groups.

[0050] A specific example of the silane coupling agent C having the preferred structure described above is X-12-972F manufactured by Shin-Etsu Silicone Co., Ltd.

[0051] (Silane coupling agent E) The silane coupling agent may also contain a silane coupling agent E other than aminosilane. The silane coupling agent E does not contain an amino group but contains a reactive functional group other than an amino group. The reactive functional group other than an amino group may be at least one selected from epoxy groups, mercapto groups, and isocyanate groups. The silane coupling agent E may contain one silicon atom in a single molecule. Examples of silane coupling agent E include silicon compounds having a hydrolyzable group represented by the following formula (III). The silicon compounds having a hydrolyzable group represented by formula (III) may be used alone or in combination of two or more.

[0052] R 3 SiY 3-n X n (III)

[0053] In equation (III), n represents an integer between 1 and 3.

[0054] R 3 This is a hydrocarbon group in which at least one hydrogen atom is substituted by a reactive functional group. The number of carbon atoms in the hydrocarbon group is not particularly limited, but is for example 1 to 6, and particularly 1 to 3. The reactive functional group is preferably an epoxy group (hereinafter, a silane coupling agent having an epoxy group may be referred to as "epoxysilane"). The epoxy group may be included as part of the glycidyl group.

[0055] X is a hydrolyzable group or a halogen atom. Specific examples of hydrolyzable groups and halogen atoms are as described above. Y is an alkyl group having 1 to 3 carbon atoms. Specific examples of alkyl groups having 1 to 3 carbon atoms are as described above.

[0056] Compounds in which X in formula (III) is an alkoxyl group are called silicon alkoxides. In formula (III), preferably n is 3. That is, the silane coupling agent E is preferably R in formula (III). 3 It is a trifunctional silicon alkoxide having a reactive functional group represented as SiX3.

[0057] A preferred specific example of the silane coupling agent E is a glycidoxyalkyltrialkoxysilane. Examples of glycidoxyalkyltrialkoxysilanes are 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane (GPTMS), and 3-glycidoxypropyltriethoxysilane.

[0058] In the anti-fogging film, the silane coupling agent reacts with other components at least partially to form a cross-linked structure. Other components include organic components such as water-absorbing polymers and hydroxyl groups on the substrate surface.

[0059] The silane coupling agent A, silane coupling agent B, and / or silane coupling agent C should be added in a mass ratio of, for example, 1:5 to 5:1, particularly in the range of 1:3 to 3:1. The total amount of these aminosilanes and silane coupling agent E should be added in a mass ratio of 1:2 to 5:1, particularly in the range of 1:1 to 3:1.

[0060] The content of the silane coupling agent in the anti-fogging film is, for example, 1 to 40% by mass, preferably 3 to 30% by mass, and more preferably 6 to 25% by mass.

[0061] Silane coupling agent A is a component that can contribute to making it difficult for polyether-modified siloxane to leach out of the anti-fogging film. If polyether-modified siloxane does not leach out of the anti-fogging film even after it has been in contact with moisture for a long time, the anti-fogging film is more likely to maintain its hydrophilicity. Silane coupling agent B is a component that can impart appropriate hydrophobicity to the anti-fogging film. If the appropriate hydrophobicity of the anti-fogging film can suppress the penetration of water between the anti-fogging film and the resin substrate even after it has been in contact with moisture for a long time, the anti-fogging film is more likely to maintain its adhesion to the resin substrate. Silane coupling agent C is a component that can improve the adhesion of the anti-fogging film to the resin substrate through multiple amino groups.

[0062] (Other ingredients) In addition to the components mentioned above, the anti-fogging film may also contain, as appropriate, ultraviolet absorbers, infrared absorbers, leveling agents (surface modifiers), light stabilizers, etc. However, it is desirable that these components be added in an amount of 20% by mass or less, more preferably 10% by mass or less, and particularly less than 5% by mass of the anti-fogging film. Colloidal silica and other silica fine particles may or may not be included in the anti-fogging film. The silica fine particle content in the anti-fogging film may be, for example, 10 to 60% by mass, but may be limited to less than 5% by mass, more preferably less than 3% by mass, and particularly less than 1% by mass. The content of oxide fine particles including silica fine particles may also be as described above for silica fine particles. The anti-fogging film may or may not contain oxide fine particles represented by silica fine particles. However, even if silica fine particles are not included, the anti-fogging film may contain siloxane components contained in polyether-modified siloxanes, silane coupling agents, etc.

[0063] [Adhesive layer] The adhesive layer 13 only needs to be able to fix the resin substrate 1 with anti-fogging film to the location or part to be attached with sufficient strength, as will be described later. Specifically, an adhesive can be used that is polymerized from monomers such as (meth)acrylic or rubber that have tackiness at room temperature and set to a desired glass transition temperature. Examples of acrylic monomers include methyl acrylate, ethyl acrylate, butyl acrylate, stearyl acrylate, and 2-ethylhexyl acrylate, while examples of methacrylic monomers include ethyl methacrylate, butyl methacrylate, isobutyl methacrylate, and stearyl methacrylate. When applying by heat lamination, an organic substance that softens at the lamination temperature may be used. The glass transition temperature can be adjusted, for example, by changing the blending ratio of monomers.

[0064] [Protective sheet and release sheet] The protective sheet 12 and the release sheet 14 are positioned to protect the anti-fogging film 11 and the adhesive layer 13, respectively. The release sheet 14 can be made of a sheet-like substrate such as polyethylene terephthalate, polypropylene, or polyethylene, to which a release agent such as silicone is applied. That is, the surface of the substrate to which the release agent is applied is attached to the adhesive layer 13. The protective sheet 12 can be made of a substrate similar to the release sheet 14, to which a weak adhesive that is easy to peel off is applied.

[0065] [Manufacturing method for resin substrates with anti-fog coating] Next, a method for manufacturing the resin substrate 1 with an anti-fogging film will be described. First, an anti-fogging film 11 is formed on one side of the resin substrate 10. The anti-fogging film can be formed by applying a coating solution for forming the anti-fogging film (coating solution for forming the anti-fogging film) to the surface of the resin substrate and heating the resin substrate on which the coating film has been formed. The solvent used to prepare the coating solution and the method of applying the coating solution can be conventionally known materials and methods. Examples of application methods include spin coating, roll coating, spray coating, dip coating, flow coating, screen printing, and brush coating. The coating film may be dried as appropriate before heating.

[0066] The heating temperature of the resin substrate on which the coating film is formed is not particularly limited, but is, for example, 100 to 180°C, and the heating time is, for example, 5 minutes to 1 hour.

[0067] [Transparent items with anti-fog coating] The resin substrate with an anti-fog film of this embodiment can be used as an anti-fog sheet to impart anti-fog properties to articles requiring anti-fog properties, by being appropriately attached to them. Specifically, articles to which it can be attached include, for example, windows of vehicles and buildings; facades of buildings; mirrors for houses, housing equipment, vehicles and portable devices; optical components such as lenses and optical filters; cover members of image display devices; headlights of vehicles; liquid crystal displays with touch panels such as electronic blackboards; head-mounted displays used in VR (virtual reality) goggles, etc.; refrigerated display cases, refrigerators with windows, goggles used for skiing and swimming, helmets used for motorcycles, safety glasses, sunglasses, splash-proof face shields, etc., and are typically transparent articles. Transparent articles may be made of glass or resin. The resin may be acrylic resin such as methacrylic resin (PMMA), polycarbonate (PC), acrylonitrile / styrene resin (AS), acrylonitrile / butadiene / styrene resin (ABS), vinyl chloride (PVC), triacetylcellulose (TAC), and polyethylene terephthalate (PET). However, as described above, the resin substrate with the anti-fogging film of this embodiment can also be used in a form that is not attached to other articles, that is, it can be used as one of the various articles exemplified above.

[0068] [Characteristics of resin substrates with anti-fog coating] The anti-fog film according to this embodiment can transmit transmitted light without scattering at a high level, even in harsh environments for anti-fog films, such as after being in contact with water for a long period of time. To achieve this function, it is desirable that the anti-fog film has transparency, water absorption, water resistance, and hydrophilicity. Anti-fog films that do not have sufficient water resistance may have their components leached out when in contact with moisture for a long time. Furthermore, if the anti-fog film is hydrophilic enough that excess water is retained on its surface as a continuous film when its own water absorption reaches a saturation point, transmitted light can be transmitted without excessive scattering.

[0069] (Transparency / Non-diffusiveness of transmitted light) The resin substrate with an anti-fog coating according to this embodiment can transmit light without excessive scattering. Specifically, the resin substrate with an anti-fog coating may have a haze rate of, for example, 5% or less, moreover 3% or less, particularly 1% or less, and in some cases 0.4% or less. The resin substrate with an anti-fog coating may also have a haze rate of 0.3% or less, and even moreover 0.2% or less. The haze rate is specified in JIS K 7136:2018.

[0070] (Water resistance / hydrophilic) The resin substrate with an anti-fog film according to this embodiment can achieve both water resistance and hydrophilicity. These properties can be evaluated by a method called high-temperature water vapor evaluation, which is described in detail in the Examples section. In this method, high-temperature and excessive water vapor is supplied to the anti-fog film with the film facing vertically downward. When exposed to this water vapor, a transparent continuous film of water is formed on the surface of the anti-fog film, which is both hydrophilic and water-resistant, in the portion directly exposed to the water vapor. Whether it is a "transparent continuous film" can be determined by visually confirming that the film maintains continuity as a film rather than water droplets, and that the film is not cloudy. Cloudiness of the film can occur due to whitening of the film due to insufficient water resistance, or due to condensation on the film surface due to insufficient anti-fog properties. On the surface of a film with insufficient hydrophilicity, water is not retained as a continuous film but is dispersed and adheres as water droplets. Cloudiness can be observed in films with insufficient water resistance upon contact with high-temperature water vapor, and elution of film components or film defects may occur. The hydrophilicity of a surface is generally evaluated by the contact angle of water. However, this evaluation method only involves dropping a very small amount of water droplets onto the film, and therefore does not adequately reproduce harsh environments. Furthermore, the transparent continuous film may cover 80% or even 90% or more of the surface of the anti-fogging film exposed to water vapor.

[0071] To evaluate the film in more detail or in a more stepwise manner, information reading evaluation using QR codes can be performed. Details of this evaluation method will be described later in the Examples section. In this evaluation method, the resin substrate with the anti-fogging film according to this embodiment can exhibit good hydrophilicity to the extent that a QR code "A" with a size of preferably 30 mm square, a QR code "S" with a size of more preferably 20 mm square, an even more preferably 15 mm square, a QR code "SS" with a size of particularly preferably 10 mm square, and a QR code "SSS" with a size of particularly preferably 10 mm square can be read, even after being immersed in water at room temperature for 100 hours.

[0072] The coating solution according to this embodiment comprises a silane coupling agent, a water-absorbing polymer, a polyether-modified siloxane, and a diol having 2 to 8 carbon atoms. The silane coupling agent comprises silane coupling agent A and at least one silane coupling agent selected from the group consisting of silane coupling agent B and silane coupling agent C. For example, the compounds described above can be used for each component. The content of each component in the coating solution should be appropriately adjusted so that the content of each component in the anti-fogging film is within the range described above. The coating solution may also contain other components. Examples of other components are water and alcohol. [Examples]

[0073] The present invention will be described in more detail below with reference to examples. First, the evaluation method for resin substrates with anti-fogging films obtained from each example or comparative example will be explained.

[0074] (Water immersion test) A resin substrate with an anti-fog coating was immersed in a plastic container holding pure water at room temperature (approximately 25°C) and kept in this state for 100 hours. After that, the resin substrate with the anti-fog coating was removed and dried by standing it upright in a holder. The following visual evaluation and high-temperature steam evaluation were performed on the dried sample.

[0075] • Appearance evaluation The condition of the film surface was evaluated visually to determine which of the following categories it fell into. G: No change compared to before the exam. F: Slight bleaching is observed. NG: Albinism is observed. Y: Membrane elution is observed.

[0076] • Evaluation of anti-fogging properties using high-temperature steam (high-temperature steam evaluation) As shown in Figure 3A, a resin substrate 1 with an anti-fog film was horizontally held above a stainless steel insulated cup 80 containing boiling water 70, with the surface of the anti-fog film 11 facing the insulated cup 80. The temperature of the water 70 was maintained at 90-100°C while steam was being supplied. The distance D1 between the anti-fog film 11 and the water surface was 60 mm. The internal space of the insulated cup 80 was cylindrical with an opening diameter of 64 mm, and the volume of the water 70 was approximately 130 cc. The resin substrate 1 with the anti-fog film was held on the insulated cup 80 for 30 seconds to supply high-temperature steam to the anti-fog film 11. After that, as shown in Figure 3B, the insulated cup 80 was removed, and a cardboard backing 95 with a predetermined QR code 90 printed on it was placed in its place. The distance D2 between the anti-fog film 11 and the cardboard backing 95 was 110 mm. In this state, the QR code 90 was photographed from above by the camera 100 through the resin substrate 1 with an anti-fog coating, and it was confirmed whether the information contained in the QR code 90 could be read. The distance D3 between the resin substrate 10 and the lens 101 of the camera 100 was set to 80 mm. The removal of the insulated cup 80, i.e., the cessation of the supply of high-temperature steam, and the photography of the QR code were carried out within 30 seconds.

[0077] Five types of QR codes, as shown in Figures 4A to 4E, were used to identify the smallest QR code from which information could be read, and that QR code was used as the evaluation result. The size of the QR codes used and the information they contained are as follows. For example, if the QR code SSS was read, the text information "Rank:SSS" would be displayed. QR code "SSS": 10mm x 10mm, information "Rank: SSS" (Figure 4A) QR code "SS": 15mm x 15mm, information "Rank: SS" (Figure 4B) QR code "S": 20mm x 20mm, information "Rank: S" (Figure 4C) QR code "A": 30mm x 30mm, information "Rank: A" (Figure 4D) QR code "B": 40mm x 40mm, information "Rank: B" (Figure 4E)

[0078] If none of the QR codes could be read, the result was "X," and if the film dissolved or peeled off due to contact with high-temperature steam, the result was "Y."

[0079] The QR code "SSS" shown in Figure 4A was encoded as information according to the specifications of JIS X 0510:2018, with a 25x25 module symbol size and error correction level H. The QR codes "SS" to "B" shown in Figures 4B to 4E were encoded as information according to the specifications of JIS X 0510:2018, with a 21x21 module symbol size and error correction level H. Note that each string consists of half-width characters (1-byte code), not full-width characters.

[0080] The camera used was a Sony Xperia XZ2 smartphone (model name: SO-03K, OS: Android® (ver. 10)). The QR code reading function of the LINE® app (ver. 11.7.2) was used to read the QR code.

[0081] (Example 1) (Preparation of the coating solution) Polyvinyl acetal resin-containing solution (Sekisui Chemical Co., Ltd. "Eslec KX-5", solids content 8% by mass, degree of acetalization 9 mol%, containing acetal structure derived from benzaldehyde) 72.3% by mass, polyether-modified dimethylsiloxane (Nisshin Chemical Industry Co., Ltd. "Sylface SAG503A") 1.1% by mass, 3-aminopropyltriethoxysilane (APTES, Shin-Etsu Silicone Co., Ltd. "KBE-903", silane coupling agent A) 1.3% by mass, N-2-(aminoethyl)-8-aminooctyltrimethoxysilane ( A coating solution was prepared by mixing 0.5% by mass of Shin-Etsu Silicone's "KBM-6803" (silane coupling agent B), 0.7% by mass of 3-glycidoxypropyltrimethoxysilane (GPTMS, Shin-Etsu Silicone's "KBM-403" (silane coupling agent E)), 20.0% by mass of propylene glycol, 3.3% by mass of purified water, 0.8% by mass of alcohol solvent (Daishin Chemical's "Neoethanol P-7"), 0.05% by mass of hydrochloric acid, and 0.01% by mass of leveling agent (Shin-Etsu Silicone's "KP-341") in a glass container.

[0082] (Formation of an anti-fog film) A resin substrate with an anti-fogging film was obtained by applying a coating solution to a resin substrate. A polyester resin substrate (Cosmoshine A4300, manufactured by Toyobo Co., Ltd.) with an A4 size was used as the resin substrate. No prior plasma treatment or other processes were performed on the surface of the resin substrate. The coating solution was applied using an applicator through a 100 μm slit to form a coating film. Next, the resin substrate with the coated film was heated at 140°C for 9 minutes to obtain a resin substrate with an anti-fogging film.

[0083] (Examples 2 and 3) A resin substrate with an anti-fogging film was obtained in the same manner as in Example 1, except that the raw materials and quantities listed in Table 1 were used in the preparation of the coating solution. In Example 3, a polymer-type polyfunctional aminosilane (Shin-Etsu Silicone Co., Ltd. "X-12-972F"; silane coupling agent C) was used instead of silane coupling agent B. In Examples 2 and 3, the amount of alcohol solvent was reduced by the amount of silane coupling agent increased.

[0084] (Example 4) (Preparation of the coating solution) In preparing the coating solution, the coating solution was obtained in the same manner as in Example 1, except that the raw materials and amounts listed in Table 1 were used. In Example 4, the amounts of purified water and alcohol solvent were increased by the amount of water-absorbing polymer that was reduced. Specifically, in Example 4, 18.5% by mass of purified water and 9.6% by mass of alcohol solvent were used in the preparation of the coating solution.

[0085] (Formation of an anti-fog film) A resin substrate with an anti-fogging film was obtained by applying a coating solution to a resin substrate. A polycarbonate substrate (PC1600, manufactured by Takiron CI Co., Ltd.) with dimensions of 50 mm x 50 mm and a thickness of 2 mm was used as the resin substrate. The surface of the resin substrate was pre-treated with plasma. The coating solution was applied using a spin coater to form a coating film. Next, the resin substrate with the coated film was heated at 130°C for 30 minutes to obtain a resin substrate with an anti-fogging film.

[0086] (Example 5) A resin substrate with an anti-fogging film was obtained in the same manner as in Example 4, except that the raw materials and quantities listed in Table 1 were used in the preparation of the coating solution. In Example 5, the amount of alcohol solvent was reduced by the amount of propylene glycol increased.

[0087] (Comparative Examples 1-14) A resin substrate with an anti-fogging film was obtained in the same manner as in Example 1, except that the raw materials and quantities listed in Table 2 were used in the preparation of the coating solution. In Comparative Examples 1 to 14, the amount of alcohol solvent was increased by the amount of the component that was omitted.

[0088] The results of the water immersion test are shown in Tables 1 and 2. Note that among the comparative examples, those in which the anti-fogging film whitened or partially leached were not subjected to high-temperature water vapor evaluation.

[0089] [Table 1]

[0090] [Table 2]

[0091] In each example, the resin substrates with anti-fog coatings achieved a "SSS" rating in the high-temperature steam evaluation after the water immersion test. In all examples, when the supply of high-temperature steam was stopped, a continuous film of water of uniform thickness was formed on the surface of the anti-fog coating, and the transparency of the resin substrate with the anti-fog coating was ensured without any whitening of the film itself or fogging due to condensation. In each example, the transparent continuous film that received an "SSS" rating covered more than 90% of the surface of the anti-fog coating exposed to steam, or more specifically, substantially all of the surface. In contrast, in the comparative examples, after the water immersion test, cosmetic defects such as dissolution of the anti-fog coating or whitening of the film were observed, or even if not, when high-temperature steam was supplied, large water droplets were dispersed and adhered to the surface of the anti-fog coating. In Comparative Example 13, "NG,Y" indicates that the film partially dissolved, and the remaining film was also whitened.

[0092] Furthermore, the following evaluations were conducted for Examples 1 to 5. The results are shown in Table 3.

[0093] [Table 3]

[0094] (Initial state) In the initial state after the anti-fogging film was formed, the appearance was evaluated in the same manner as described above, and the haze rate was also measured.

[0095] (Repeated anti-fogging test) In the initial state after the anti-fog film was formed, high-temperature steam was supplied to the anti-fog film in the same manner as in the high-temperature steam evaluation. Then, the resin substrate with the anti-fog film was removed and dried by placing it upright in a holder. After drying, the sample was again supplied with high-temperature steam to the anti-fog film, and this drying process was repeated until high-temperature steam was supplied to the anti-fog film 10 times. Subsequently, the appearance evaluation and high-temperature steam evaluation were performed in the same manner as described above. Note that in the high-temperature steam evaluation, QR code scanning was performed immediately after the 10th steam supply (excluding the 11th steam supply).

[0096] (Alcohol abrasion test) 0.5 cc of an alcohol solvent primarily composed of ethanol (Fine Etter A-10, manufactured by Futaba Chemical Co., Ltd.) was dropped onto a 25 mm wide nonwoven fabric cloth (Bencot M-3II, manufactured by Asahi Kasei Corporation) and allowed to soak in the solvent. This cloth was then set up for a reciprocating abrasion test along with a resin substrate coated with an anti-fog film. A load of 400 g was applied to the cloth, and it was moved back and forth 20 times over a length of 30 mm. Subsequently, visual evaluation and high-temperature steam evaluation were performed in the same manner as described above.

Claims

1. A resin substrate and an anti-fog film on the surface of the resin substrate, The anti-fog film contains a water-absorbing polymer, When the anti-fog film is immersed in water at 25°C for 100 hours, taken out from the water, and exposed to water vapor generated from water at 90°C to 100°C placed 60 mm vertically downward from the anti-fog film for 30 seconds, a transparent continuous film is formed on the surface of the anti-fog film exposed to the water vapor. The anti-fog film further includes a component for improving the hydrophilicity of the surface and a cross-linked structure derived from a silane coupling agent for improving the water resistance of the anti-fog film. A resin substrate with an anti-fog film.

2. A protective sheet on the surface of the anti-fog film, And an adhesive layer formed on the surface of the resin substrate on the side opposite to the side where the anti-fog film is formed. The resin substrate with an anti-fog film according to Claim 1.

3. A transparent article with an anti-fog film, comprising the resin substrate with an anti-fog film according to Claim 1 or 2.

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