Optical sheet, layered sheet, and equipment / device

Abstract

This optical sheet comprises a layer formed from a composition containing an ethylene-unsaturated carboxylic acid copolymer (A) or an ethylene-unsaturated carboxylic acid copolymer ionomer (A1). The copolymer or the ionomer contains structural units derived from an unsaturated carboxylic acid at 5 mass% or more and has a melting point of no higher than 90°C.

Description

Optical sheets, laminated sheets and equipment devices

[0001] The present invention relates to an optical sheet, a laminated sheet, and an equipment device.

[0002] In recent years, display devices such as liquid crystal displays (LCDs) and input devices such as touch panels used in combination with the display devices have become widely used in various fields. In the manufacture of these display devices and input devices, optical sheets are used to bond optical members. Technologies related to optical sheets include those described in Patent Documents 1 to 3, for example.

[0003] Patent Document 1 describes an optical adhesive sheet that includes a pressure-sensitive adhesive layer and has a dielectric constant of 2 to 8 at a frequency of 1 MHz and a dielectric loss tangent of greater than 0 and equal to or less than 0.2, with the objective of providing an optical adhesive sheet that can suppress changes in capacitance that can cause malfunction when applied to optical components.

[0004] Patent Document 2 describes an object of providing a resin composition that can achieve good adhesive strength and holding power, high transparency, and water vapor barrier properties. The resin composition contains an isobutylene polymer (A) and an acrylate polymer (B) whose main component is a monofunctional (meth)acrylate having a long alkyl chain having 10 or more carbon atoms, and at least one maximum point of the loss tangent (tan δ) in shear at a frequency of 1 Hz is in the range of −20 to 20° C., and is characterized in that when the resin composition is observed with a transmission electron microscope (magnification: 1000 to 5000 times), no agglomerates with a maximum diameter of 1 μm or more are observed.

[0005] Patent Document 3 describes a transparent resin layer that can impart antistatic properties to a level that does not cause a decrease in the sensitivity of a touch panel, without impairing the reliability of a polarizing film that is provided on the most visible side in an image display device, and that is disposed closer to the visible side than a polarizing film that is provided on the most visible side in an image display device with a built-in touch sensor. The transparent resin layer has a transparent substrate disposed on the surface of the transparent resin layer opposite to the side on which the polarizing film is disposed, the transparent substrate being a glass plate or a transparent acrylic plate, and the transparent resin layer is bonded to the transparent substrate, and has a surface resistance of 1.0 × 10 １３ A transparent resin layer characterized by a resistivity of Ω / □ or less is described.

[0006] JP 2018-199817 A JP 2019-014888 A JP 2020-035451 A

[0007] The present invention provides an optical sheet having an improved balance of low-temperature adhesiveness, transparency, moisture resistance, and insulating properties.

[0008] The present inventors have discovered that by using an ethylene-unsaturated carboxylic acid copolymer or an ionomer of an ethylene-unsaturated carboxylic acid copolymer in which the content of structural units derived from unsaturated carboxylic acid and the melting point are within specific numerical ranges, an optical sheet can be obtained that has an improved balance of low-temperature adhesion, transparency, moisture resistance, and insulating properties.

[0009] The present invention provides the following optical sheet, laminated sheet, and equipment device.

[0010] [1] An optical sheet comprising a layer made of a composition containing an ethylene-unsaturated carboxylic acid copolymer (A) or an ionomer (A1) of an ethylene-unsaturated carboxylic acid copolymer, the composition containing 5% by mass or more of structural units derived from an unsaturated carboxylic acid and having a melting point of 90°C or less. [2] The optical sheet according to [1] above, wherein the content of the ethylene-unsaturated carboxylic acid copolymer (A) or the ionomer (A1) of the ethylene-unsaturated carboxylic acid copolymer in the composition is 80% by mass or more, based on the total mass of the composition. [3] The optical sheet according to [1] or [2] above, wherein the adhesive strength of the composition to a glass plate, measured by the following (Method 1), is 2.0 N / 15 mm or more. (Method 1) A sheet of 120 mm x 75 mm x 0.2 mm made of the composition is obtained. The sheet is then laminated on the tin side of a 120 mm x 75 mm x 3.9 mm glass plate, and vacuum-laminated for 3 minutes at a heating temperature of 80°C using a vacuum laminator. The sheet is then pressed for 5 minutes at a heating temperature of 80°C and 0.1 MPa (gauge pressure) to adhere the sheet to the tin side of the glass plate. The sheet is then peeled away from the glass plate at a peel angle of 180°C and a pulling rate of 100 mm / min, and the maximum stress measured is calculated as the adhesive strength (N / 15 mm) to the glass plate. [4] The optical sheet according to any one of [1] to [3] above, wherein the ethylene-unsaturated carboxylic acid copolymer (A) comprises at least one copolymer selected from the group consisting of an ethylene-α,β-unsaturated carboxylic acid copolymer and an ethylene-α,β-unsaturated carboxylic acid-α,β-unsaturated carboxylic acid ester copolymer. [5] The optical sheet according to the above [4], wherein the α,β-unsaturated carboxylic acid ester of the ethylene / α,β-unsaturated carboxylic acid ester copolymer contains isobutyl (meth)acrylate. [6] The optical sheet according to any one of the above [1] to [5], wherein the ethylene / unsaturated carboxylic acid copolymer of the ionomer (A1) of the ethylene / unsaturated carboxylic acid copolymer contains at least one copolymer selected from the group consisting of an ethylene / α,β-unsaturated carboxylic acid copolymer and an ethylene / α,β-unsaturated carboxylic acid / α,β-unsaturated carboxylic acid ester copolymer.[7] The optical sheet according to [6] above, wherein the α,β-unsaturated carboxylic acid ester of the ethylene / α,β-unsaturated carboxylic acid / α,β-unsaturated carboxylic acid ester copolymer contains isobutyl (meth)acrylate. [8] A laminated sheet comprising the optical sheet according to any one of [1] to [7] above and a base layer. [9] An equipment device comprising the optical sheet according to any one of [1] to [7] above.

[0011] According to the present invention, an optical sheet having an improved balance of low-temperature adhesiveness, transparency, moisture resistance, and insulating properties can be provided.

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all drawings, similar components are designated by common reference numerals, and descriptions thereof will be omitted where appropriate. Furthermore, the drawings are schematic diagrams and do not necessarily correspond to actual dimensional ratios. In this specification, "A to B" indicating a numerical range means A or more and B or less, unless otherwise specified. In this specification, "(meth)acrylic" means acrylic, methacrylic, or both acrylic and methacrylic.

[0013] 1. Optical Sheet The optical sheet of this embodiment includes a layer made of a composition containing an ethylene-unsaturated carboxylic acid copolymer (A) or an ionomer (A1) of an ethylene-unsaturated carboxylic acid copolymer, which has a content of structural units derived from an unsaturated carboxylic acid of 5% by mass or more and a melting point of 90° C. or less. The content of structural units derived from an unsaturated carboxylic acid is a value when all structural units in the ethylene-unsaturated carboxylic acid copolymer (A) or the ionomer (A1) of an ethylene-unsaturated carboxylic acid copolymer in the composition are taken as 100% by mass.

[0014] According to the optical sheet of the present embodiment, by using an ethylene-unsaturated carboxylic acid copolymer or an ionomer of an ethylene-unsaturated carboxylic acid copolymer in which the content of structural units derived from unsaturated carboxylic acid and the melting point are within specific numerical ranges, it is possible to improve the balance of performance among low-temperature adhesion, transparency, moisture resistance, and insulation.

[0015] The adhesive strength of the composition constituting the layer of the optical sheet of this embodiment to a glass plate by the following (Method 1) is preferably 2.0 N / 15 mm or more, more preferably 2.3 N / 15 mm or more, even more preferably 2.5 N / 15 mm or more, even more preferably 2.8 N / 15 mm or more, and even more preferably 3.0 N / 15 mm or more, from the viewpoint of further improving the performance balance of low-temperature adhesion, transparency, moisture resistance, and insulating properties. The upper limit of the adhesive strength is not particularly limited, and may be, for example, 50.0 N / 15 mm or less, 40.0 N / 15 mm or less, 30.0 N / 15 mm or less, 20.0 N / 15 mm or less, or 10.0 N / 15 mm or less. Furthermore, from the viewpoint of further improving the performance balance of low-temperature adhesion, transparency, moisture resistance, and insulating properties, the adhesive strength of the optical sheet of this embodiment is preferably 2.0 N / 15 mm or more and 50.0 N / 15 mm or less, more preferably 2.3 N / 15 mm or more and 40.0 N / 15 mm or less, even more preferably 2.5 N / 15 mm or more and 30.0 N / 15 mm or less, even more preferably 2.8 N / 15 mm or more and 20.0 N / 15 mm or less, and even more preferably 3.0 N / 15 mm or more and 10.0 N / 15 mm or less.

[0016] (Method 1) A 120 mm x 75 mm x 0.2 mm sheet composed of the above composition is obtained. Next, the sheet is laminated on the tin side of a 120 mm x 75 mm x 3.9 mm glass plate, and after vacuum-holding for 3 minutes at a heating temperature of 80 ° C. using a vacuum laminator, the sheet is pressed at a heating temperature of 80 ° C. and 0.1 MPa (gauge pressure) for 5 minutes to adhere the sheet to the tin side of the glass plate. Next, the sheet is peeled from the glass plate at a peel angle of 180 ° C. and a pulling rate of 100 mm / min. The maximum stress when peeled is calculated as the adhesive strength (N / 15 mm) to the glass plate.

[0017] The adhesive strength of the composition constituting the layer of the optical sheet of this embodiment to a glass plate after 1000 hours by the following (Method 2) is preferably 9.0 N / 15 mm or more, more preferably 10.0 N / 15 mm or more, even more preferably 12.0 N / 15 mm or more, even more preferably 13.0 N / 15 mm or more, even more preferably 14.0 N / 15 mm or more, and even more preferably 15.0 N / 15 mm or more, from the viewpoint of further improving the performance balance of low-temperature adhesion, transparency, moisture resistance, and insulation. The upper limit of the adhesive strength after 1000 hours is not particularly limited, but may be, for example, 100.0 N / 15 mm or less, 90.0 N / 15 mm or less, 80.0 N / 15 mm or less, 70.0 N / 15 mm or less, 60.0 N / 15 mm or less, 50.0 N / 15 mm or less, 40.0 N / 15 mm or less, or 30.0 N / 15 mm or less. Furthermore, from the viewpoint of further improving the performance balance of low-temperature adhesion, transparency, moisture resistance, and insulating properties, the adhesive strength of the optical sheet of this embodiment after 1,000 hours is preferably 9.0 N / 15 mm or more and 100.0 N / 15 mm or less, more preferably 10.0 N / 15 mm or more and 90.0 N / 15 mm or less, even more preferably 10.0 N / 15 mm or more and 80.0 N / 15 mm or less, even more preferably 12.0 N / 15 mm or more and 70.0 N / 15 mm or less, even more preferably 12.0 N / 15 mm or more and 60.0 N / 15 mm or less, even more preferably 13.0 N / 15 mm or more and 50.0 N / 15 mm or less, even more preferably 14.0 N / 15 mm or more and 40.0 N / 15 mm or less, and even more preferably 15.0 N / 15 mm or more and 30.0 N / 15 mm or less.

[0018] (Method 2) A 120 mm x 75 mm x 0.2 mm sheet composed of the above composition is obtained. Next, the sheet is laminated on the tin side of a 120 mm x 75 mm x 3.9 mm glass plate, and after 3 minutes of vacuum holding at a heating temperature of 80 ° C. in a vacuum laminator, the sheet is pressed at a heating temperature of 80 ° C. and 0.1 MPa (gauge pressure) for 5 minutes to adhere the sheet to the tin side of the glass plate. Then, the sheet and the glass plate are stored for 1000 hours under conditions of 85 ° C. and 90% RH. Next, the sheet is peeled from the glass plate at a peel angle of 180 ° C. and a pulling rate of 100 mm / min. The maximum stress when peeled off is calculated as the adhesive strength (N / 15 mm) to the glass plate after 1000 hours.

[0019] The thickness of the optical sheet of this embodiment is preferably 1 μm or more and 2000 μm or less, more preferably 10 μm or more and 1000 μm or less, even more preferably 50 μm or more and 500 μm or less, and even more preferably 100 μm or more and 300 μm or less, from the viewpoint of further improving the performance balance of low-temperature adhesion, transparency, moisture resistance, and insulation.

[0020] The total light transmittance of the optical sheet of this embodiment, measured in accordance with JIS K7136:2000, is preferably 70% or more, more preferably 75% or more, even more preferably 80% or more, and even more preferably 85% or more, from the viewpoint of further improving transparency. The upper limit of the total light transmittance is not particularly limited, but may be, for example, 100% or less, 98% or less, 95% or less, or 93% or less. Furthermore, the total light transmittance of the optical sheet of this embodiment is preferably 70% or more and 100% or less, more preferably 75% or more and 98% or less, even more preferably 80% or more and 95% or less, and even more preferably 85% or more and 93% or less.

[0021] The haze of the optical sheet of this embodiment, measured in accordance with JIS K7136:2000, is preferably 40% or less, more preferably 30% or less, even more preferably 20% or less, and even more preferably 10% or less, from the viewpoint of further improving transparency. The lower limit of the haze is not particularly limited, and may be, for example, 0% or more, 1% or more, 3% or more, or 5% or more. Furthermore, the haze of the optical sheet of this embodiment is preferably 0% or more and 40% or less, more preferably 1% or more and 30% or less, even more preferably 3% or more and 20% or less, and even more preferably 5% or more and 10% or less.

[0022] The moisture permeability of the optical sheet of this embodiment, measured by the cup method (based on JIS Z0208:1976, measurement atmosphere: 40°C x 90% RH), is preferably 15 g / (m), from the viewpoint of further improving the performance balance between moisture permeability resistance and long-term reliability. ２ 24h) or less, more preferably 13g / (m ２ 24h) or less, more preferably 10g / (m ２ 24h) or less, more preferably 8g / (m ２ The lower limit of the moisture permeability is not particularly limited, but is, for example, 0.01 g / (m ２ 24h) or more, and ２ 24h) or more, and may be 0.5g / (m ２ 24h) or more, and may be 1.0 g / (m ２ The moisture permeability of the optical sheet of the present embodiment may be preferably 0.01 g / (m 2 ) or more, from the viewpoint of further improving the balance of moisture permeability resistance and long-term reliability. ２ ・24h) or more 15g / (m ２ 24h) or less, more preferably 0.1g / (m ２ ・24h) or more 13g / (m ２ 24h) or less, more preferably 0.5g / (m ２ ・24h) or more 10g / (m ２ 24h) or less, more preferably 1.0 g / (m ２ ・24h) or more 8g / (m２ ・24h) or less.

[0023] The volume resistivity of the optical sheet of this embodiment, measured in accordance with JIS C2139:2008, is preferably 1.00 × 10 from the viewpoint of further improving the performance balance between insulation properties and long-term reliability. １０ Ω cm or more, more preferably 1.00 × 10 １２ Ω cm or more, more preferably 1.00 × 10 １５ Ω cm or more, more preferably 1.00 × 10 １７ The upper limit of the specific volume resistivity is not particularly limited, but is, for example, 1.00×10 ２０ Ω cm or less, and may be 1.00 × 10 １９ Ω cm or less, and may be 1.00 × 10 １８ Ω cm or less, and may be 5.00 × 10 １７ The volume resistivity of the optical sheet of the present embodiment may be preferably 1.00×10 Ω·cm or less, from the viewpoint of further improving the balance of insulation properties and long-term reliability. １０ Ω・cm or more 1.00×10 ２０ Ω cm or less, more preferably 1.00 × 10 １２ Ω・cm or more 1.00×10 １９ Ω cm or less, more preferably 1.00 × 10 １５ Ω・cm or more 1.00×10 １８ Ω cm or less, more preferably 1.00 × 10 １７ Ω・cm or more 5.00×10 １７ It is Ω·cm or less.

[0024] In the ethylene-unsaturated carboxylic acid copolymer (A) or the ionomer (A1) of the ethylene-unsaturated carboxylic acid copolymer, from the viewpoint of further improving the performance balance of transparency, flexibility, adhesiveness, heat resistance, and mechanical strength, the content of structural units derived from ethylene is preferably 65% ​​by mass or more and 95% by mass or less, more preferably 70% by mass or more and 95% by mass or less, even more preferably 75% by mass or more and 94% by mass or less, and still more preferably 80% by mass or more and 93% by mass or less, when all structural units in the ethylene-unsaturated carboxylic acid copolymer (A) or the ionomer (A1) of the ethylene-unsaturated carboxylic acid copolymer are taken as 100% by mass. Furthermore, in the ethylene-unsaturated carboxylic acid copolymer (A) or the ionomer (A1) of the ethylene-unsaturated carboxylic acid copolymer, from the viewpoint of further improving the performance balance of transparency, flexibility, adhesiveness, heat resistance, and mechanical strength, the content of structural units derived from unsaturated carboxylic acids is preferably 5% by mass or more and 35% by mass or less, more preferably 5% by mass or more and 30% by mass or less, even more preferably 6% by mass or more and 25% by mass or less, even more preferably 7% by mass or more and 20% by mass or less, and still more preferably 8% by mass or more and 15% by mass or less, when all structural units in the ethylene-unsaturated carboxylic acid copolymer (A) or the ionomer (A1) of the ethylene-unsaturated carboxylic acid copolymer are taken as 100% by mass.

[0025] The melting point of the ethylene-unsaturated carboxylic acid copolymer (A) or the ionomer (A1) of the ethylene-unsaturated carboxylic acid copolymer is preferably 89°C or lower, more preferably 88°C or lower, and even more preferably 87°C or lower, from the viewpoint of further improving the performance balance of transparency, flexibility, adhesiveness, heat resistance, and mechanical strength. The lower limit of the melting point is not particularly limited, and may be, for example, 60°C or higher, 65°C or higher, 70°C or higher, or 75°C or higher. Furthermore, the melting point of the ethylene-unsaturated carboxylic acid copolymer (A) or the ionomer (A1) of the ethylene-unsaturated carboxylic acid copolymer in the composition of this embodiment is preferably 60°C or higher and 90°C or lower, more preferably 65°C or higher and 89°C or lower, even more preferably 70°C or higher and 88°C or lower, and even more preferably 75°C or higher and 87°C or lower, from the viewpoint of further improving the performance balance of transparency, flexibility, adhesiveness, heat resistance, and mechanical strength.

[0026] The ethylene-unsaturated carboxylic acid copolymer (A) and the ionomer (A1) of the ethylene-unsaturated carboxylic acid copolymer in the composition of this embodiment preferably comprise at least one selected from the group consisting of an ethylene-α,β-unsaturated carboxylic acid copolymer and an ethylene-α,β-unsaturated carboxylic acid-α,β-unsaturated carboxylic acid ester copolymer, from the viewpoint of further improving the balance of low-temperature adhesion, transparency, moisture resistance, and insulating properties. Furthermore, when the composition of this embodiment comprises the ethylene-unsaturated carboxylic acid copolymer (A), the ethylene-unsaturated carboxylic acid copolymer (A) more preferably comprises an ethylene-α,β-unsaturated carboxylic acid-α,β-unsaturated carboxylic acid ester copolymer.

[0027] Examples of the α,β-unsaturated carboxylic acid in the ethylene / α,β-unsaturated carboxylic acid copolymer or the ethylene / α,β-unsaturated carboxylic acid / α,β-unsaturated carboxylic acid ester copolymer include acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, maleic anhydride, itaconic anhydride, monomethyl maleate, and monoethyl maleate. Among these, from the viewpoint of further improving the productivity and hygiene of the ethylene / unsaturated carboxylic acid copolymer (A) or the ionomer (A1) of the ethylene / unsaturated carboxylic acid copolymer, and the balance of the low-temperature adhesiveness, transparency, moisture resistance, and insulating properties of the optical sheet, preferably the copolymer contains at least one selected from acrylic acid and methacrylic acid, more preferably methacrylic acid, and even more preferably methacrylic acid. These unsaturated carboxylic acids may be used alone or in combination of two or more.

[0028] Examples of the ester in the ethylene / α,β-unsaturated carboxylic acid copolymer or the ethylene / α,β-unsaturated carboxylic acid / α,β-unsaturated carboxylic acid ester copolymer include methyl ester, ethyl ester, n-propyl ester, isopropyl ester, n-butyl ester, isobutyl ester, 2-ethylhexyl ester, etc. Among these, isobutyl ester is preferred from the viewpoint of further improving the productivity and hygiene of the ethylene / unsaturated carboxylic acid copolymer (A) or the ionomer (A1) of the ethylene / unsaturated carboxylic acid copolymer, and the balance of the low-temperature adhesiveness, transparency, moisture resistance, and insulating properties of the optical sheet.

[0029] In the ethylene-unsaturated carboxylic acid copolymer (A) or the ionomer (A1) of the ethylene-unsaturated carboxylic acid copolymer in the composition of the present embodiment, the α,β-unsaturated carboxylic acid ester of the ethylene-α,β-unsaturated carboxylic acid-α,β-unsaturated carboxylic acid ester copolymer preferably contains isobutyl (meth)acrylate, and more preferably contains isobutyl acrylate, from the viewpoint of further improving the productivity and hygiene of the ethylene-unsaturated carboxylic acid copolymer (A) or the ionomer (A1) of the ethylene-unsaturated carboxylic acid copolymer, and the balance of performance such as low-temperature adhesiveness, transparency, moisture impermeability resistance, and insulating properties of the optical sheet.

[0030] When the composition of the present embodiment contains an ionomer (A1) of an ethylene-unsaturated carboxylic acid copolymer, examples of the ion source in the ionomer include alkali metals such as lithium and sodium; and polyvalent metals such as calcium, magnesium, zinc, and aluminum.

[0031] The ionomer used has a degree of neutralization of, for example, 80% or less. When the degree of neutralization is within the above range, an optical sheet having excellent transparency and high-temperature storage stability can be obtained. From the viewpoints of the transparency, adhesiveness, and processability of the optical sheet, the degree of neutralization of the ionomer (A1) is preferably 70% or less, more preferably 60% or less, even more preferably 55% or less, even more preferably 50% or less, even more preferably 45% or less, and even more preferably 40% or less. The lower limit of the degree of neutralization is not particularly limited, but may be, for example, 1% or more, preferably 2% or more, more preferably 3% or more, even more preferably 4% or more, and even more preferably 5% or more. Furthermore, from the viewpoints of the transparency, adhesiveness, and processability of the perovskite solar cell encapsulant, the degree of neutralization of the ionomer (A1) is preferably 1% or more and 70% or less, more preferably 2% or more and 60% or less, even more preferably 2% or more and 55% or less, even more preferably 3% or more and 50% or less, even more preferably 4% or more and 45% or less, and even more preferably 5% or more and 40% or less.

[0032] The ethylene-unsaturated carboxylic acid copolymer (A) can be obtained by radical copolymerization of each polymerization component under high temperature and high pressure, and the ionomer (A1) of the ethylene-unsaturated carboxylic acid copolymer can be obtained by reacting the ethylene-unsaturated carboxylic acid copolymer (A) with a metal compound.

[0033] From the viewpoint of further improving processability and mechanical properties, the ethylene-unsaturated carboxylic acid copolymer (A) or the ionomer (A1) of the ethylene-unsaturated carboxylic acid copolymer preferably has a melt flow rate (JIS K7210:1999) at 190°C under a load of 2160 g of 0.1 g / 10 min or more and 150 g / 10 min or less, more preferably 0.1 g / 10 min or more and 50 g / 10 min or less.

[0034] The content of the ethylene-unsaturated carboxylic acid copolymer (A) or the ionomer (A1) of the ethylene-unsaturated carboxylic acid copolymer in the composition of the present embodiment is preferably 80% by mass or more, and more preferably 90% by mass or more, based on 100% by mass of the entire composition, from the viewpoint of further improving the balance of low-temperature adhesion, transparency, moisture resistance, and insulating properties.

[0035] The composition of the present embodiment may contain various additives within the scope of the present invention, such as a crosslinking agent, a crosslinking aid, a silane coupling agent, an ultraviolet absorber, a light stabilizer, and an antioxidant.

[0036] As the crosslinking agent, an organic peroxide having a decomposition temperature of 1 hour half-life of, for example, 90 to 180° C., preferably 100 to 150° C. is preferably used. From the viewpoint of further improving the performance balance of low-temperature adhesiveness, moisture resistance, and mechanical properties, the organic peroxide in the composition of this embodiment is preferably t-butylperoxyisopropyl carbonate, t-butylperoxyacetate, t-butylperoxybenzoate, dicumyl peroxide, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane, di-t-butyl peroxide, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexyne-3, 1,1-bis(t-butylperoxy)-3, The composition of the present embodiment includes one or more crosslinking agents selected from the group consisting of 3,5-trimethylcyclohexane, 1,1-bis(t-butylperoxy)cyclohexane, methyl ethyl ketone peroxide, 2,5-dimethylhexyl-2,5-bisperoxybenzoate, t-butyl hydroperoxide, p-menthane hydroperoxide, benzoyl peroxide, p-chlorobenzoyl peroxide, t-butylperoxyisobutyrate, hydroxyheptyl peroxide, and dicyclohexanone peroxide. The content of the crosslinking agent in the composition of the present embodiment is preferably 0.1 parts by mass or more and 5 parts by mass or less, more preferably 0.5 parts by mass or more and 3 parts by mass or less, per 100 parts by mass of the ethylene-unsaturated carboxylic acid copolymer (A) or the ionomer (A1) of the ethylene-unsaturated carboxylic acid copolymer, from the viewpoint of further improving the performance balance of low-temperature adhesion, moisture permeation resistance, and mechanical properties.

[0037] From the viewpoint of further improving the balance of low-temperature adhesion, moisture resistance, and mechanical properties, the crosslinking aid in the composition of this embodiment preferably contains at least one polyunsaturated compound selected from the group consisting of polyallyl compounds and poly(meth)acryloxy compounds, and more preferably contains one or more compounds selected from the group consisting of polyallyl compounds, poly(meth)acryloxy compounds, and divinylbenzene. The polyallyl compound of this embodiment preferably contains one or more compounds selected from the group consisting of triallyl isocyanurate, triallyl cyanurate, diallyl phthalate, diallyl fumarate, and diallyl maleate. The poly(meth)acryloxy compound of this embodiment preferably contains at least one compound selected from the group consisting of ethylene glycol diacrylate, ethylene glycol dimethacrylate, and trimethylolpropane trimethacrylate. From the viewpoint of further improving the performance balance of low-temperature adhesion, moisture resistance, and mechanical properties, the content of the crosslinking aid in the composition of the present embodiment is preferably 0.1 parts by mass or more and 5 parts by mass or less, more preferably 0.5 parts by mass or more and 3 parts by mass or less, relative to 100 parts by mass of the ethylene-unsaturated carboxylic acid copolymer (A) or the ionomer of the ethylene-unsaturated carboxylic acid copolymer (A1).

[0038] From the viewpoint of further improving the performance balance of low-temperature adhesion, moisture resistance, and mechanical properties, the silane coupling agent in the composition of the present embodiment preferably contains a silane coupling agent having a vinyl group, an amino group, or an epoxy group and a hydrolyzable group such as an alkoxy group, and more preferably contains one or more selected from the group consisting of vinyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-acryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, N-2-(aminoethyl)3-aminopropyltrimethoxysilane, N-2-(aminoethyl)3-aminopropylmethyldiethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, and N-phenyl-3-aminopropyltriethoxysilane. Among these, from the viewpoint of further improving the performance balance of low-temperature adhesion, moisture resistance, and mechanical properties, the silane coupling agent in the composition of the present embodiment preferably includes one or more types selected from the group consisting of silane coupling agents having an amino group, silane coupling agents having a dimethoxy group, and silane coupling agents having a trimethoxy group, more preferably includes one or more types selected from the group consisting of silane coupling agents having an amino group and silane coupling agents having a dimethoxy group, and even more preferably includes a silane coupling agent having an amino group and a dimethoxy group.

[0039] Examples of the silane coupling agent having an amino group and a dimethoxy group according to this embodiment include N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane and N-2-(aminomethyl)-3-aminopropylmethyldimethoxysilane.

[0040] The content of the silane coupling agent in the composition of this embodiment is, from the viewpoint of further improving the performance balance of low-temperature adhesion, moisture permeability resistance and mechanical properties, preferably 0.01 parts by mass or more and 5 parts by mass or less, more preferably 0.02 parts by mass or more and 4 parts by mass or less, even more preferably 0.03 parts by mass or more and 3 parts by mass or less, even more preferably 0.04 parts by mass or more and 2 parts by mass or less, even more preferably 0.05 parts by mass or more and 1.5 parts by mass or less, even more preferably 0.06 parts by mass or more and 1.0 parts by mass or less, even more preferably 0.07 parts by mass or more and 0.9 parts by mass or less, even more preferably 0.08 parts by mass or more and 0.8 parts by mass or less, even more preferably 0.09 parts by mass or more and 0.7 parts by mass or less, and even more preferably 0.10 parts by mass or more and 0.6 parts by mass or less.

[0041] From the viewpoint of further improving the performance balance of low-temperature adhesion, moisture resistance, and mechanical properties, the content of the silane coupling agent having an amino group and a dimethoxy group in the composition of this embodiment is preferably 30% by mass or more and 100% by mass or less, more preferably 50% by mass or more and 100% by mass or less, and even more preferably 70% by mass or more and 100% by mass or less, when the total amount of the silane coupling agent in the composition of this embodiment is taken as 100% by mass.

[0042] In order to prevent deterioration of the optical sheet due to ultraviolet rays, it is preferable to add an ultraviolet absorber, a light stabilizer, an antioxidant, and the like to the composition of this embodiment.

[0043] Examples of the ultraviolet absorber include benzophenone-based ultraviolet absorbers such as 2-hydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-2-carboxybenzophenone, and 2-hydroxy-4-n-octoxybenzophenone; 2-(2H-benzotriazol-2-yl)-4,6-di-tert-pentylphenol, 2-(2'-hydroxy-3',5'-di-t-butylphenyl)benzotriazole, 2-[2-hydroxy-3,5-b Examples of usable ultraviolet absorbers include benzotriazole-based ultraviolet absorbers such as [2-(2'-hydroxy-5-methylphenyl)benzotriazole]-2H-benzotriazole, 2-(2'-hydroxy-5-t-octylphenyl)benzotriazole, and fatty acid ester-based ultraviolet absorbers such as phenyl salicylate, p-octylphenyl salicylate, and methanetetrayltetramethanol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate].

[0044] Examples of the light stabilizer that can be used include hindered amine-based light stabilizers such as bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate. Examples of the antioxidant that can be used include hindered phenol-based antioxidants such as 2-[4,6-bis([1,1'-biphenyl]-4-yl)-1,3,5-triazin-2-yl]-5-[(2-ethylhexyl)oxy]phenol, and phosphite-based antioxidants. The content of each of the antioxidant, light stabilizer, and UV absorber is preferably 0.01 to 5 parts by mass, more preferably 0.1 to 3 parts by mass, per 100 parts by mass of the ethylene-unsaturated carboxylic acid copolymer (A) or the ionomer (A1) of the ethylene-unsaturated carboxylic acid copolymer.

[0045] In addition to the additives described above, the composition of the present embodiment may contain additives such as a light diffusing agent and a flame retardant, if necessary.

[0046] Examples of the light diffusing agent include inorganic spherical substances such as glass beads, silica beads, silicon alkoxide beads, hollow glass beads, etc. Examples of organic spherical substances include acrylic or vinylbenzene plastic beads, etc.

[0047] Examples of the flame retardant include halogen-based flame retardants such as bromides, phosphorus-based flame retardants, silicone-based flame retardants, and metal hydrates such as magnesium hydroxide and aluminum hydroxide.

[0048] The optical sheet of this embodiment can preferably be used for one or more components selected from the group consisting of components constituting devices such as display devices and input devices, or components used in these devices, and more preferably can be used for one or more components selected from the group consisting of polarizing plates, wavelength plates, retardation plates, image display panels, optical compensation films, brightness enhancement films, light guide plates, reflective films, anti-reflection films, transparent conductive films (such as ITO films), design films, decorative films, surface protection films, prisms, lenses, color filters, flexible substrates, and transparent substrates, or components in which these are laminated.

[0049] 2. Laminate Sheet The laminate sheet of the present embodiment preferably includes the optical sheet of the present embodiment and a substrate layer, from the viewpoint of further improving the balance of performance among low-temperature adhesion, transparency, moisture resistance, and insulating properties.

[0050] The overall thickness of the laminate sheet of this embodiment is preferably 5 μm or more and 2100 μm or less, more preferably 10 μm or more and 1100 μm or less, even more preferably 50 μm or more and 600 μm or less, and even more preferably 100 μm or more and 400 μm or less, from the viewpoint of further improving the performance balance of low-temperature adhesion, transparency, moisture resistance, and insulation.

[0051] <Substrate Layer> The substrate layer of the laminate sheet of this embodiment is a layer provided for the purpose of improving the handleability, mechanical properties, heat resistance, and other properties of the laminate sheet. Examples of the substrate layer in the laminate sheet of this embodiment include plate-shaped materials (sheets or films) made of polyester (e.g., polyethylene terephthalate), polyethylene, polypropylene, polystyrene, polyamide, silica-deposited polyester, etc. Among these, from the viewpoint of further improving the performance balance of the handleability, mechanical properties, transparency, moisture resistance, and insulating properties of the laminate sheet, the substrate layer in the laminate sheet of this embodiment preferably includes a plate-shaped material made of one or more materials selected from the group consisting of polyester, polypropylene, polystyrene, polyamide, and silica-deposited polyester, and more preferably includes a sheet or film made of polyethylene terephthalate. These substrate layers may have not only a single-layer structure, but also a laminate structure of two or more layers.

[0052] The thickness of the substrate layer in the laminate sheet of this embodiment is preferably 5 μm or more and 100 μm or less, more preferably 10 μm or more and 50 μm or less, from the viewpoint of further improving the performance balance of low-temperature adhesion, transparency, moisture resistance, and insulation.

[0053] The surface of the base material layer in the laminate sheet of this embodiment that is to be bonded (or laminated) with the optical sheet of this embodiment may be subjected to a physical treatment such as corona treatment, plasma treatment, or flame treatment in order to increase the adhesive strength with the optical sheet of this embodiment. Also, the base material layer may be subjected to a known anchor coating treatment.

[0054] <Intermediate Layer> The laminate sheet of this embodiment preferably further includes an intermediate layer from the viewpoint of further improving the balance of low-temperature adhesion, transparency, moisture resistance, and insulating properties. The intermediate layer of this embodiment preferably contains an ethylene-unsaturated carboxylic acid copolymer or an ionomer thereof as a main component. Here, "main component" means that the ethylene-unsaturated carboxylic acid copolymer or an ionomer thereof is contained in an amount of 60 mass% or more in the intermediate layer.

[0055] In the ethylene-unsaturated carboxylic acid copolymer or its ionomer, from the viewpoint of further improving the performance balance of transparency, flexibility, adhesiveness, heat resistance, and mechanical strength, the content of structural units derived from ethylene is preferably from 65 to 95% by mass, more preferably from 75 to 92% by mass, when all structural units in the ethylene-unsaturated carboxylic acid copolymer or its ionomer are taken as 100% by mass. Furthermore, in the ethylene-unsaturated carboxylic acid copolymer or its ionomer, from the viewpoint of further improving the performance balance of transparency, flexibility, adhesiveness, heat resistance, and mechanical strength, the content of structural units derived from unsaturated carboxylic acid is preferably from 5 to 35% by mass, more preferably from 8 to 25% by mass, when all structural units in the ethylene-unsaturated carboxylic acid copolymer or its ionomer are taken as 100% by mass.

[0056] Examples of the unsaturated carboxylic acid in the ethylene-unsaturated carboxylic acid copolymer include acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, maleic anhydride, itaconic anhydride, monomethyl maleate, and monoethyl maleate. Among these, from the viewpoints of productivity and hygiene of the ethylene-unsaturated carboxylic acid copolymer, at least one selected from acrylic acid and methacrylic acid is preferred. These unsaturated carboxylic acids may be used alone or in combination of two or more.

[0057] From the viewpoint of improving the flexibility of the laminate sheet of this embodiment, the ethylene-unsaturated carboxylic acid copolymer may contain structural units derived from other copolymerizable monomers in an amount of preferably 0% by mass to 30% by mass, more preferably 0% by mass to 25% by mass, relative to 100% by mass of the total of the ethylene and unsaturated carboxylic acid copolymer. Examples of the other copolymerizable monomers include unsaturated esters, for example, vinyl esters such as vinyl acetate and vinyl propionate; and (meth)acrylic acid esters such as methyl (meth)acrylate, ethyl (meth)acrylate, isobutyl (meth)acrylate, n-butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate.

[0058] In this embodiment, an ionomer thereof can be used instead of the ethylene-unsaturated carboxylic acid copolymer. By including an ionomer of an ethylene-unsaturated carboxylic acid copolymer as the main component of the intermediate layer, the moisture permeation resistance of the laminate sheet of this embodiment can be further improved. Examples of ion sources for the ionomer include alkali metals such as lithium and sodium; and polyvalent metals such as calcium, magnesium, zinc, and aluminum.

[0059] The ionomer used has a degree of neutralization of, for example, 80% or less. A degree of neutralization within the above range allows for the production of a laminate sheet with excellent transparency and high-temperature storage stability. From the viewpoints of the transparency, adhesiveness, and processability of the laminate sheet, the degree of neutralization of the ionomer is preferably 70% or less, more preferably 60% or less, even more preferably 55% or less, even more preferably 50% or less, even more preferably 45% or less, and even more preferably 40% or less. The lower limit of the degree of neutralization is not particularly limited, but may be, for example, 1% or more, preferably 2% or more, more preferably 3% or more, even more preferably 4% or more, and even more preferably 5% or more. Furthermore, from the viewpoints of the transparency, adhesiveness, and processability of the perovskite solar cell encapsulant, the degree of neutralization of the ionomer is preferably 1% or more and 70% or less, more preferably 2% or more and 60% or less, even more preferably 2% or more and 55% or less, even more preferably 3% or more and 50% or less, even more preferably 4% or more and 45% or less, and even more preferably 5% or more and 40% or less.

[0060] The ethylene-unsaturated carboxylic acid copolymer can be obtained by radical copolymerization of the respective polymerization components under high temperature and pressure, and the ionomer can be obtained by reacting such a copolymer with a metal compound.

[0061] From the viewpoint of further improving processability and mechanical properties, the ethylene-unsaturated carboxylic acid copolymer or its ionomer preferably has a melt flow rate (JIS K7210:1999) at 190°C under a load of 2160 g of 0.1 g / 10 min or more and 150 g / 10 min or less, more preferably 0.1 g / 10 min or more and 50 g / 10 min or less.

[0062] In the intermediate layer constituting the laminate sheet of this embodiment, the content of the ethylene-unsaturated carboxylic acid copolymer or its ionomer is preferably 80% by mass or more, and more preferably 90% by mass or more, when the entire intermediate layer is taken as 100% by mass, in order to further improve the performance balance of low-temperature adhesion, transparency, moisture resistance, and insulation.

[0063] The intermediate layer may contain various additives within the scope of the present invention, such as a crosslinking agent, a crosslinking aid, a silane coupling agent, an ultraviolet absorber, a light stabilizer, and an antioxidant.

[0064] As the crosslinking agent, an organic peroxide having a decomposition temperature of 1 hour half-life of usually 90 to 180° C., preferably 100 to 150° C. is preferably used. From the viewpoint of further improving the performance balance of low-temperature adhesiveness, moisture resistance, and mechanical properties, the organic peroxide in the intermediate layer constituting the laminate sheet of this embodiment is preferably t-butylperoxyisopropyl carbonate, t-butylperoxyacetate, t-butylperoxybenzoate, dicumyl peroxide, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane, di-t-butyl peroxide, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexyne-3, 1,1-bis(t-butylperoxy) The laminate sheet of the present embodiment may contain one or more crosslinking agents selected from the group consisting of (i)-3,3,5-trimethylcyclohexane, 1,1-bis(t-butylperoxy)cyclohexane, methyl ethyl ketone peroxide, 2,5-dimethylhexyl-2,5-bisperoxybenzoate, t-butyl hydroperoxide, p-menthane hydroperoxide, benzoyl peroxide, p-chlorobenzoyl peroxide, t-butylperoxyisobutyrate, hydroxyheptyl peroxide, and dicyclohexanone peroxide. The content of the crosslinking agent in the intermediate layer constituting the laminate sheet of the present embodiment is preferably 0.1 parts by mass or more and 5 parts by mass or more, more preferably 0.5 parts by mass or more and 3 parts by mass or less, based on 100 parts by mass of the ethylene-unsaturated carboxylic acid copolymer or its ionomer, from the viewpoint of further improving the balance of low-temperature adhesion, moisture resistance, and mechanical properties.

[0065] In order to further improve the balance of low-temperature adhesion, moisture resistance, and mechanical properties, the crosslinking aid in the intermediate layer constituting the laminate sheet of this embodiment preferably contains at least one polyunsaturated compound selected from the group consisting of polyallyl compounds and poly(meth)acryloxy compounds, and more preferably contains one or more polyallyl compounds, poly(meth)acryloxy compounds, and divinylbenzene. The polyallyl compound of this embodiment preferably contains one or more polyallyl isocyanurate, triallyl cyanurate, diallyl phthalate, diallyl fumarate, and diallyl maleate. The poly(meth)acryloxy compound of this embodiment preferably contains at least one polyallyl compound selected from the group consisting of ethylene glycol diacrylate, ethylene glycol dimethacrylate, and trimethylolpropane trimethacrylate. The content of the cross-linking aid in the intermediate layer constituting the laminate sheet of this embodiment is preferably 0.1 parts by mass or more and 5 parts by mass or less, more preferably 0.5 parts by mass or more and 3 parts by mass or less, relative to 100 parts by mass of the ethylene-unsaturated carboxylic acid copolymer or its ionomer, from the viewpoint of further improving the performance balance of low-temperature adhesion, moisture resistance, and mechanical properties.

[0066] Examples of the silane coupling agent in the intermediate layer constituting the laminate sheet of this embodiment include silane coupling agents having a vinyl group, an amino group, or an epoxy group and a hydrolyzable group such as an alkoxy group, etc. Among these, vinyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-acryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, N-2-(aminoethyl)3-aminopropyltrimethoxysilane, N-2-(aminoethyl)3-aminopropylmethyldiethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, and N-phenyl-3-aminopropyltriethoxysilane. The content of the silane coupling agent in the intermediate layer constituting the laminate sheet of this embodiment is preferably 0.01 parts by mass or more and 5 parts by mass or less, more preferably 0.02 parts by mass or more and 3 parts by mass or less, when the content of the ethylene-unsaturated carboxylic acid copolymer or its ionomer is taken as 100 parts by mass, from the viewpoint of further improving the performance balance of low-temperature adhesion, moisture resistance, and mechanical properties.

[0067] In order to prevent deterioration of the laminated sheet due to ultraviolet rays, it is preferable that the intermediate layer contains an ultraviolet absorber, a light stabilizer, an antioxidant, etc.

[0068] Examples of the ultraviolet absorber include benzophenone-based ultraviolet absorbers such as 2-hydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-2-carboxybenzophenone, and 2-hydroxy-4-n-octoxybenzophenone; benzotriazole-based ultraviolet absorbers such as 2-(2H-benzotriazol-2-yl)-4,6-di-tert-pentylphenol, 2-(2'-hydroxy-3',5'-di-t-butylphenyl)benzotriazole, 2-(2'-hydroxy-5-methylphenyl)benzotriazole, and 2-(2'-hydroxy-5-t-octylphenyl)benzotriazole; and salicylate-based ultraviolet absorbers such as phenyl salicylate and p-octylphenyl salicylate.

[0069] As the light stabilizer, a hindered amine light stabilizer or the like is used. As the antioxidant, various hindered phenol antioxidants, phosphite antioxidants, etc. are used. The contents of the antioxidant, light stabilizer, and ultraviolet absorber are each preferably 0.01 parts by mass or more and 5 parts by mass or less, more preferably 0.1 parts by mass or more and 3 parts by mass or less, relative to 100 parts by mass of the ethylene-unsaturated carboxylic acid copolymer or its ionomer.

[0070] In addition to the above-mentioned additives, the intermediate layer may contain additives such as a light diffusing agent and a flame retardant, if necessary.

[0071] Examples of the light diffusing agent include inorganic spherical substances such as glass beads, silica beads, silicon alkoxide beads, hollow glass beads, etc. Examples of organic spherical substances include acrylic or vinylbenzene plastic beads, etc.

[0072] Examples of the flame retardant include halogen-based flame retardants such as bromides, phosphorus-based flame retardants, silicone-based flame retardants, and metal hydrates such as magnesium hydroxide and aluminum hydroxide.

[0073] When the laminate sheet of this embodiment further comprises an intermediate layer, from the viewpoint of further improving the performance balance of transparency, adhesion, moisture impermeability, insulation, flexibility, heat resistance, and processability, the ratio (a / b) of the thickness (a) of the intermediate layer to the thickness (b) of the optical sheet is preferably 1 / 1 or more and 10 / 1 or less, more preferably 2 / 1 or more and 6 / 1 or less. Note that when the laminate sheet of this embodiment comprises a plurality of the optical sheets and the intermediate layers, the thicknesses of the optical sheets and the intermediate layers may be different, as long as the thicknesses of the optical sheets and the intermediate layers are in the above thickness ratio.

[0074] 3. Equipment Device The equipment device of this embodiment preferably includes the optical sheet of this embodiment. The equipment device of this embodiment can be used for one or more components selected from the group consisting of components constituting equipment such as display devices and input devices, or components used in such equipment, and more preferably for one or more components selected from the group consisting of polarizing plates, wavelength plates, retardation plates, image display panels, optical compensation films, brightness enhancement films, light guide plates, reflective films, anti-reflection films, transparent conductive films (such as ITO films), design films, decorative films, surface protection films, prisms, lenses, color filters, flexible substrates, transparent substrates, or components on which these are laminated.

[0075] Examples of the display device include a liquid crystal display device, an organic EL (electroluminescence) display device, a PDP (plasma display panel), electronic paper, a camera (display unit), etc. Examples of the input device include a touch panel, a camera (lens unit), etc.

[0076] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various other configurations may be adopted. Furthermore, the present invention is not limited to the above-described embodiments, and modifications and improvements within the scope of achieving the object of the present invention are included in the present invention.

[0077] The present embodiment will be described in detail below with reference to examples, etc. However, the present embodiment is not limited to the descriptions of these examples.

[0078] [Materials] The following components were used.

[0079] <Ethylene-Unsaturated Carboxylic Acid Copolymer and Ionomer of Ethylene-Unsaturated Carboxylic Acid Copolymer> Copolymer 1: Ethylene-Methacrylic Acid-Isobutyl Acrylate Copolymer (Ethylene Content: 80% by Mass, Methacrylic Acid Content: 10% by Mass, Isobutyl Acrylate Content: 10% by Mass, Melting Point: 86°C) Copolymer 2: Ethylene-Methacrylic Acid-Isobutyl Acrylate Copolymer (Ethylene Content: 75% by Mass, Methacrylic Acid Content: 8% by Mass, Isobutyl Acrylate Content: 17% by Mass, Melting Point: 80°C) Copolymer 3: Ethylene-Methacrylic Acid Copolymer (Ethylene Content: 85% by Mass, Methacrylic Acid Content: 15% by Mass, Melting Point: 93°C)

[0080] <Weather-resistant agent masterbatch> Weather-resistant agent masterbatch 1: 94.2 parts by mass of ionomer of ethylene-methacrylic acid copolymer (ethylene content: 85% by mass, methacrylic acid content: 15% by mass, metal ion: zinc ion, degree of neutralization: 23%), 3.0 parts by mass of 2-[2-hydroxy-3,5-bis(α,α-dimethylbenzyl)phenyl]-2H-benzotriazole (manufactured by BASF Japan Ltd., Tinuvin 234), 2-[4,6-bis([1,1'-biphenyl]-4-yl)-1,3,5-triazin-2-yl]-5- Weathering agent master batch 1 was obtained by pre-mixing 0.6 parts by mass of [(2-ethylhexyl)oxy]phenol (manufactured by BASF Japan Ltd., TINUVIN 1600), 1.9 parts by mass of bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate (manufactured by BASF Japan Ltd., TINUVIN 770DF), and 0.3 parts by mass of methanetetrayltetramethanol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (manufactured by BASF Japan Ltd., Ir1010).

[0081] <Silane Coupling Agent> Silane Coupling Agent 1: N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBM-602)

[0082] [Examples 1 to 4 and Comparative Examples 1 and 2] Using a resin composition obtained by dry-blending each material in the compounding ratio (unit: parts by mass) shown in Table 1, a film was formed using a T-die molding machine at a processing temperature of 140°C to produce a sheet of each example having a length of 120 mm, a width of 75 mm, and a thickness of 0.2 mm.

[0083] <Evaluation Method> (1) Adhesion Evaluation Using a vacuum laminator (double vacuum chamber laminator manufactured by NPC Corporation, LM-50x50S), the sheet of each example was laminated on the tin side of a glass sheet measuring 120 mm length x 75 mm width x 3.9 mm thickness, and then vacuum-held at a heating temperature of 80 ° C for 3 minutes. After that, the sheet was pressed at a heating temperature of 80 ° C and 0.1 MPa (gauge pressure) for 5 minutes to adhere the sheet to the tin side of the glass plate. The laminate was then left to stand in the air and slowly cooled by natural cooling. A 15 mm wide slit was made in the sheet portion of the completed laminate to prepare a test specimen, which was then placed in a tensile tester. Next, the sheet was peeled from the glass plate at a peel angle of 180 ° C and a tensile speed of 100 mm / min, and the maximum stress was determined as the adhesive strength (initial) (unit: N / 15 mm) to the glass plate. The laminate was also stored for 1000 hours under conditions of 85 ° C and 90% RH. After storage, a 15 mm wide slit was made in the sheet portion of the laminate to prepare a test specimen, which was then placed in a tensile tester. The sheet was then peeled away from the glass plate at a peel angle of 180°C and a pulling rate of 100 mm / min, and the maximum stress was determined as the adhesive strength to the glass plate (after 1000 hours) (unit: N / 15 mm). The results are shown in Table 1.

[0084] (2) Transparency Evaluation A laminate was prepared by laminating 3.2 mm thick glass / each example sheet / 3.2 mm thick glass in this order in the same manner as in the adhesiveness evaluation in (1), and the total light transmittance (unit: %) and haze (cloudiness, unit: %) of the laminate were measured in accordance with JIS K7136:2000 using a haze meter manufactured by Suga Test Instruments Co., Ltd. The results are shown in Table 1.

[0085] (3) Moisture Permeability Evaluation The moisture permeability (unit: g / (m)) of the sheet obtained by the cup method (JIS Z0208:1976 compliant, measurement atmosphere: 40°C x 90% RH) was measured. ２ The results are shown in Table 1.

[0086] (4) Volume Resistivity The volume resistivity (unit: Ω cm) of the obtained sheet was measured in accordance with JIS C2139: 2008. The results are shown in Table 1.

[0087]

[0088] The sheets of Examples 1 to 4 had an excellent balance of low-temperature adhesion, transparency, moisture resistance, and insulating properties. In contrast, the sheets of Comparative Examples 1 and 2 had an inferior balance of low-temperature adhesion, transparency, moisture resistance, and insulating properties.

[0089] This application claims priority based on Japanese Patent Application No. 2024-055641, filed March 29, 2024, the disclosure of which is incorporated herein by reference in its entirety.

Claims

1. An optical sheet comprising a layer made of a composition containing an ethylene-unsaturated carboxylic acid copolymer (A) or an ionomer (A1) of an ethylene-unsaturated carboxylic acid copolymer, the content of which is 5% by mass or more and which is derived from an unsaturated carboxylic acid and which has a melting point of 90°C or less.

2. The optical sheet according to claim 1, wherein the content of the ethylene-unsaturated carboxylic acid copolymer (A) or the ionomer (A1) of the ethylene-unsaturated carboxylic acid copolymer in the composition is 80 mass% or more relative to the entire composition.

3. The optical sheet according to claim 1 or 2, wherein the adhesive strength of the composition to a glass plate is 2.0 N / 15 mm or more, as determined by the following (Method 1). (Method 1) A 120 mm x 75 mm x 0.2 mm sheet composed of the composition is obtained. The sheet is then laminated onto the tin side of a 120 mm x 75 mm x 3.9 mm glass plate, and the sheet is vacuum-laminated for 3 minutes at a heating temperature of 80°C using a vacuum laminator. The sheet is then pressed for 5 minutes at a heating temperature of 80°C and 0.1 MPa (gauge pressure) to adhere the sheet to the tin side of the glass plate. The sheet is then peeled away from the glass plate at a peel angle of 180°C and a pulling rate of 100 mm / min, and the maximum stress is calculated as the adhesive strength (N / 15 mm) to the glass plate.

4. The optical sheet according to any one of claims 1 to 3, wherein the ethylene-unsaturated carboxylic acid copolymer (A) comprises at least one selected from the group consisting of an ethylene-α,β-unsaturated carboxylic acid copolymer and an ethylene-α,β-unsaturated carboxylic acid-α,β-unsaturated carboxylic acid ester copolymer.

5. The optical sheet according to claim 4, wherein the α,β-unsaturated carboxylic acid ester of the ethylene / α,β-unsaturated carboxylic acid / α,β-unsaturated carboxylic acid ester copolymer contains isobutyl (meth)acrylate.

6. The optical sheet according to any one of claims 1 to 5, wherein the ethylene-unsaturated carboxylic acid copolymer of the ionomer (A1) of ethylene-unsaturated carboxylic acid copolymer comprises at least one copolymer selected from the group consisting of an ethylene-α,β-unsaturated carboxylic acid copolymer and an ethylene-α,β-unsaturated carboxylic acid-α,β-unsaturated carboxylic acid ester copolymer.

7. The optical sheet according to claim 6, wherein the α,β-unsaturated carboxylic acid ester of the ethylene / α,β-unsaturated carboxylic acid / α,β-unsaturated carboxylic acid ester copolymer contains isobutyl (meth)acrylate.

8. A laminated sheet comprising the optical sheet according to any one of claims 1 to 7 and a substrate layer.

9. An equipment device comprising the optical sheet according to any one of claims 1 to 7.

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