Protective layer and foldable device

Abstract

The present invention pertains to: a protective layer which is used in a foldable device having a glass-made cover window and contains at least one among the following (A)-(C); and a foldable device having said protective layer. The present invention thus provides: a protective layer which can be used in a foldable device having a glass-made cover window and has excellent smoothness, pencil hardness, and scatter prevention properties; and a foldable device having said protective layer.　(A) Polymer of a polymerizable compound having at least one hydrogen bonding group and at least three (meth)acrylic groups in the molecule and having a hydrogen-bonding proton value of at least 3.5 mol / kg and a (meth)acrylic value of at least 4.8 mol / kg (B) Compound containing a metal coordination bond (C) Compound containing a host-guest bond

Description

Technical Field

[0001] The present invention relates to a protective layer and a foldable device. More specifically, the present invention relates to a protective layer provided on the surface of a cover window of a foldable device having a glass cover window, and a foldable device having the protective layer.

Background Art

[0002] In recent years, devices that can be folded (foldable devices), such as smartphones, have been developed. Since foldable devices can fold, fold, or roll displays such as liquid crystal display devices (LCDs) and electroluminescent displays (ELDs), they can be applied to various uses such as smartphones, mobile phones, tablet PCs, navigation devices, e-books, TVs, monitors, etc., and are expected.

[0003] Conventionally, cover windows provided on the front surface (the surface on which an image is displayed) of foldable devices have been made of resin from the viewpoint of bending resistance. In recent years, however, glass cover windows have also been proposed (see, for example, Patent Documents 1 to 5).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Summary of the Invention

[0005] Chemically strengthened glass is typically used as the glass cover window for foldable devices. However, thin chemically strengthened glass can shatter into sharp pieces, so a protective layer is usually applied to the surface to prevent shattering. However, applying a conventional protective layer to a glass cover window presented a problem: it compromised the advantages of the glass cover window, such as its smooth surface and hardness. The object of the present invention is to provide a protective layer that can be used in a foldable device having a glass cover window, which is excellent in smoothness, pencil hardness, and shatter resistance, and a foldable device having the protective layer. [Means for solving the problem]

[0006] The inventors of this invention have conducted thorough research and found that the above problem can be solved by the following means.

[0007] <1> A protective layer used in a foldable device having a glass cover window, A protective layer comprising at least one of the following (A) to (C). (A) A polymer of a polymerizable compound having one or more hydrogen-bonding groups and three or more (meth)acrylic groups in the molecule, with a hydrogen-bonding proton value of 3.5 mol / kg or more and a (meth)acrylic value of 4.8 mol / kg or more. (B) Compounds containing metal coordination bonds (C) Compounds containing host-guest bonds <2> The elastic modulus of the above protective layer is 6 GPa or higher, and the elongation at break is 10% or higher. <1> The protective layer described above. <3> The elongation at break of the above protective layer is 23% or more. <2> The protective layer described above. <4> The thickness of the above cover window is 100 μm or less. <1> ~ <3> A protective layer as described in any one of the items. <5> The protective layer includes (A), and the hydrogen bonding group of (A) is at least one selected from the group consisting of a hydroxyl group, a carboxyl group, a urethane group, an amino group, an amide group, a urea group, a boronic acid group, a thiourethane group, a thioamide group, and a thiourea group. <1> ~ <4> A protective layer as described in any one of the items. <6> The thickness of the above protective layer is 10 μm or less. <1> ~ <5> A protective layer as described in any one of the items. <7> The protective layer has an adhesive or bonding layer with a thickness of 1 μm or less on at least one surface. <1> ~ <6> A protective layer as described in any one of the items. <8> At least one surface of the above protective layer has a scratch-resistant layer. <1> ~ <7> A protective layer as described in any one of the items. <9> The scratch-resistant layer described above includes at least one of the following (A) to (C): <8> The protective layer described above. (A) A polymer of a polymerizable compound having one or more hydrogen-bonding groups and three or more (meth)acrylic groups in the molecule, with a hydrogen-bonding proton value of 3.5 mol / kg or more and a (meth)acrylic value of 4.8 mol / kg or more. (B) Compounds containing metal coordination bonds (C) Compounds containing host-guest bonds <10> A foldable device having a glass cover window and a protective layer provided on the cover window, The above protective layer <1> ~ <6> A foldable device having a protective layer as described in any one of the items. <11> The thickness of the above cover window is 100 μm or less. <10> Foldable devices as described above. <12> Between the protective layer and the cover window, there is an adhesive layer or bonding layer with a thickness of 1 μm or less. <10> or <11> Foldable devices as described above. <13> The protective layer has a scratch-resistant layer on the surface opposite to the cover window side. <10> ~ <12> A foldable device as described in any one of the items. <14> The scratch-resistant layer described above includes at least one of the following (A) to (C): <13> Foldable devices as described above. (A) A polymer of a polymerizable compound having one or more hydrogen-bonding groups and three or more (meth)acrylic groups in the molecule, with a hydrogen-bonding proton value of 3.5 mol / kg or more and a (meth)acrylic value of 4.8 mol / kg or more. (B) Compounds containing metal coordination bonds (C) Compounds containing host-guest bonds [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a protective layer that can be used in a foldable device having a glass cover window, the protective layer having excellent smoothness, pencil hardness, and shatter resistance, and a foldable device having the protective layer. [Brief explanation of the drawing]

[0009] [Figure 1] These are schematic diagrams of the samples from Examples 1-9, 15, 16, and Comparative Examples 4-5. [Figure 2] These are schematic diagrams of the samples from Examples 10-12. [Figure 3] This is a schematic diagram of the samples from Examples 13 and 14. [Figure 4] This is a schematic diagram of the sample for Comparative Example 1. [Figure 5] These are schematic diagrams of the samples for Comparative Examples 2 and 3. [Modes for carrying out the invention]

[0010] The following describes in detail embodiments for carrying out the present invention, but the present invention is not limited thereto. In this specification, when numerical values ​​represent physical properties, characteristic values, etc., the notation "(numerical value 1) ~ (numerical value 2)" means "(numerical value 1) or more and (numerical value 2) or less". Also in this specification, the notation "(meth)acrylate" means "at least one of acrylate and methacrylate". The same applies to "(meth)acrylic acid", "(meth)acryloyl", "(meth)acrylamide", "(meth)acryloyloxy", etc. "(meth)acrylic group" means "at least one of acrylic group and methacrylic group". "(meth)acrylic value" means "at least one of acrylic value and methacrylic value".

[0011] [Protective layer] The protective layer of the present invention is a protective layer used in a foldable device having a glass cover window, The protective layer includes at least one of the following (A) to (C). (A) A polymer of a polymerizable compound having one or more hydrogen-bonding groups and three or more (meth)acrylic groups in the molecule, with a hydrogen-bonding proton value of 3.5 mol / kg or more and a (meth)acrylic value of 4.8 mol / kg or more. (B) Compounds containing metal coordination bonds (C) Compounds containing host-guest bonds

[0012] The protective layer of the present invention comprises at least one of the above (A) to (C). The following explains each of (A) through (C).

[0013] (A) (A) is a polymer of a polymerizable compound having one or more hydrogen-bonding groups and three or more (meth)acrylic groups in its molecule, with a hydrogen-bonding proton value of 3.5 mol / kg or more and a (meth)acrylic value of 4.8 mol / kg or more.

[0014] Hereinafter, "a polymerizable compound having one or more hydrogen-bonding groups and three or more (meth)acrylic groups in its molecule, with a hydrogen-bonding proton value of 3.5 mol / kg or more and a (meth)acrylic value of 4.8 mol / kg or more" will also be referred to as "polymerizable compound (a1)".

[0015] <Polymerizable compound (a1)> Polymerizable compound (a1) is a polymerizable compound having one or more hydrogen-bonding groups and three or more (meth)acrylic groups in its molecule, with a hydrogen-bonding proton value of 3.5 mol / kg or more and a (meth)acrylic value of 4.8 mol / kg or more. The polymerizable compound (a1) is described below.

[0016] (Hydrogen bonding group) Polymerizable compound (a1) has one or more hydrogen bonding groups in its molecule. A hydrogen bonding group is a group that contains a hydrogen atom (proton) capable of forming hydrogen bonds. A hydrogen atom capable of forming hydrogen bonds is a hydrogen atom that is covalently bonded to an atom with high electronegativity and can form hydrogen bonds with nearby nitrogen atoms, oxygen atoms, etc. The hydrogen bonding group of the polymerizable compound (a1) is not particularly limited and may be a generally known hydrogen bonding group. The hydrogen bonding group of the polymerizable compound (a1) is preferably at least one selected from the group consisting of a hydroxyl group, a carboxyl group, a urethane group, an amino group, an amide group, a urea group, a boronic acid group, a thiourethane group, a thioamide group, and a thiourea group; more preferably at least one selected from the group consisting of a urethane group, a thiourethane group, a urea group, a thiourea group, an amide group, and a thioamide group; and even more preferably a urea group. In the present invention, an amide group represents a divalent linking group represented by -NH-C(=O)-, a urethane group represents a divalent linking group represented by -NH-C(=O)-O-, a urea group represents a divalent linking group represented by -NH-C(=O)-NH-, a thiourethane group represents a divalent linking group represented by -NH-C(=S)-O-, a thiourea group represents a divalent linking group represented by -NH-C(=S)-NH-, and a thioamide group represents a divalent linking group represented by -NH-C(=S)-.

[0017] (Hydrogen-bonded proton valence) The hydrogen bonding proton value of polymerizable compound (a1) is 3.5 mol / kg or higher. The hydrogen bonding proton value represents the density of hydrogen atoms (protons) in a compound that can form hydrogen bonds, and is calculated using the following formula (i).

[0018] Hydrogen bonding proton value = Amount of substance (mol) of hydrogen atoms (protons) capable of forming hydrogen bonds within one molecule of the compound / Mass (kg) of one molecule of the compound ... (i)

[0019] Furthermore, the number of hydrogen atoms that can form hydrogen bonds in the amide group and thioamide group is 1, the number of hydrogen atoms that can form hydrogen bonds in the urethane group and thiourethane group is 1, and the number of hydrogen atoms that can form hydrogen bonds in the urea group and thiourea group is 2.

[0020] This section explains how to determine the proton value of hydrogen bonding when polymerizable compound (a1) is a polymer with constituent units. A constituent unit is a repeating unit. For example, if polymerizable compound (a1) is a polymer formed by polymerizing only one type of monomer, then polymerizable compound (a1) has one type of constituent unit. If it is a copolymer of two types of monomers, then it has two types of constituent units.

[0021] If the polymerizable compound (a1) has one type of structural unit, the proton value of the hydrogen bonding of the polymerizable compound (a1) is the hydrogen bonding value of the single structural unit calculated by formula (i) above.

[0022] If the polymerizable compound (a1) has multiple constituent units, the hydrogen bonding proton value of the polymerizable compound (a1) is defined as the sum of the values ​​obtained by multiplying the hydrogen bonding proton value of each constituent unit calculated by formula (i) above by the composition ratio (mol%) of each constituent unit in the polymerizable compound (a1) and dividing by 100 (average mole fraction).

[0023] Specifically, when a polymerizable compound (a1) has two constituent units (constituent unit 1 and constituent unit 2), the proton value of the hydrogen bonding of the polymerizable compound (a1) is calculated from the following formula (iiA).

[0024] Hydrogen bonding proton value = H1 (hydrogen bonding proton value of constituent unit 1) × W1 (composition ratio of constituent unit 1 (mol%)) / 100 + H2 (hydrogen bonding proton value of constituent unit 2) × W2 (composition ratio of constituent unit 2 (mol%)) / 100 ... (iiA)

[0025] Furthermore, if the polymerizable compound (a1) has constituent unit 1, constituent unit 2, ... constituent unit X (where X is an integer of 3 or more), the proton value of the hydrogen bonding of the polymerizable compound (a1) is calculated from the following formula (iiB).

[0026] Hydrogen bonding proton value = H1 (hydrogen bonding proton value of constituent unit 1) × W1 (composition ratio of constituent unit 1 (mol%)) / 100 + H2 (hydrogen bonding proton value of constituent unit 2) × W2 (composition ratio of constituent unit 2 (mol%)) / 100 + … H X (Proton valence of hydrogen bonding of constituent unit X) × W X (Composition ratio of constituent unit X (mol%)) / 100···(iiB)

[0027] The proton value of hydrogen bonding in polymerizable compound (a1) is 3.5 mol / kg or higher. This makes it possible to increase the density of hydrogen bonds formed by polymerizable compound (a1), and is therefore presumed to increase the surface hardness (pencil hardness) of the protective layer containing the polymerized product of polymerizable compound (a1). Furthermore, since hydrogen bonds can be reversibly dissociated and reformed, stress during strain can be relieved by the dissociation of hydrogen bonds, and it is presumed that the reformation of hydrogen bonds after structural change can impart flexibility to the protective layer. In addition, when an impact force is applied, since it can be reversibly dissociated and reformed, it is presumed that the protective layer absorbs the force in the thickness direction while dispersing the force in the planar direction, thereby providing shatterproof properties.

[0028] The hydrogen bonding proton value in polymerizable compound (a1) is 3.5 mol / kg or more, preferably 4.0 mol / kg or more, more preferably 5.0 mol / kg or more, and even more preferably 6.0 mol / kg or more. Furthermore, from the viewpoint of improving solubility and suppressing the generation of aggregates during film formation, the hydrogen bonding proton value of the polymerizable compound (a1) is preferably 20.0 mol / kg or less, more preferably 17.5 mol / kg or less, even more preferably 15.0 mol / kg or less, and still more preferably 12.5 mol / kg or less.

[0029] ((meth)acrylic value) Polymerizable compound (a1) has three or more (meth)acrylic groups in its molecule. That is, polymerizable compound (a1) has at least three groups selected from the group consisting of acrylic groups (acryloyl groups) and methacrylic groups (methacryloyl groups) (groups represented by the following general formula (T)) in its molecule.

[0030] [ka]

[0031] In general formula (T), Q 1* represents a hydrogen atom or a methyl group, and * represents the bond position.

[0032] In general formula (T), Q 1 If it is a hydrogen atom, it is an acrylic group, Q 1 If it's a methyl group, it's a methacrylic group. In the general formula (T), * represents a bond position, but the type of atom bonded at * is not particularly limited. For example, when bonded to an oxygen atom at *, the group represented by general formula (T), including this oxygen atom, becomes a (meth)acryloyloxy group. Also, when bonded to a nitrogen atom (a hydrogen atom or a nitrogen atom bonded to a substituent) at *, the group represented by general formula (T), including this nitrogen atom, becomes a (meth)acryloylamino group ((meth)acrylamide group).

[0033] Furthermore, the (meth)acrylamide group contains an amide group and is also a hydrogen bonding group.

[0034] The (meth)acrylic value represents the density of (meth)acrylic groups in a compound and is calculated using the following formula (iii).

[0035] (meth)acrylic value = amount of (meth)acrylic groups in one molecule of the compound (mol) / mass of one molecule of the compound (kg) ... (iii)

[0036] This section explains how to determine the (meth)acrylic value when the polymerizable compound (a1) is a polymer with constituent units. If polymerizable compound (a1) is a polymer having one type of structural unit, the (meth)acrylic value calculated for one structural unit shall be taken as the (meth)acrylic value of polymerizable compound (a1).

[0037] If the polymerizable compound (a1) has multiple constituent units, the (meth)acrylic value of the polymerizable compound (a1) is the sum of the values ​​obtained by multiplying the (meth)acrylic value of each constituent unit calculated by formula (iii) above by the composition ratio (mol%) of each constituent unit in the polymerizable compound (a1) and dividing by 100 (average mole fraction).

[0038] Specifically, when a polymerizable compound (a1) has two constituent units (constituent unit 1 and constituent unit 2), the (meth)acrylic value of polymerizable compound (a1) is calculated from the following formula (ivA).

[0039] (Meth)acrylic value = C1 ((meth)acrylic value of constituent unit 1) × W1 (composition ratio of constituent unit 1 (mol%)) / 100 + C2 ((meth)acrylic value of constituent unit 2) × W2 (composition ratio of constituent unit 2 (mol%)) / 100 ... (ivA)

[0040] Furthermore, if the polymerizable compound (a1) has constituent unit 1, constituent unit 2, ... constituent unit X (where X is an integer of 3 or more), the (meth)acrylic value of the polymerizable compound (a1) is calculated from the following formula (ivB).

[0041] (Meth)acrylic value = C1 ((meth)acrylic value of constituent unit 1) × W1 (composition ratio of constituent unit 1 (mol%)) / 100 + C2 ((meth)acrylic value of constituent unit 2) × W2 (composition ratio of constituent unit 2 (mol%)) / 100 + ... Cx ((meth)acrylic of constituent unit X) × W X (Composition ratio of constituent unit X (mol%)) / 100···(ivB)

[0042] The (meth)acrylic value of polymerizable compound (a1) is 4.8 mol / kg or more, preferably 5.0 mol / kg or more, and more preferably 5.4 mol / kg or more.

[0043] The (meth)acrylic value of polymerizable compound (a1) can be estimated by dissolving the sample in a suitable solvent, adding a fixed amount of thiol that reacts quantitatively with the (meth)acrylic group to induce an ene-thiol reaction, and measuring the amount of thiol consumed. The amount of thiol consumed can be quantified by NMR (Nuclear Magnetic Resonance) or GC (Gas Chromatography).

[0044] The number of (meth)acrylic groups in the polymerizable compound (a1) is preferably 3 to 20, more preferably 3 to 12, and even more preferably 3 to 8.

[0045] (The sum of the hydrogen-bonding proton value and the (meth)acrylic value) The sum of the hydrogen bonding proton value and (meth)acrylic value of polymerizable compound (a1) is not particularly limited, but is preferably 10.5 mol / kg or more, more preferably 11.0 mol / kg or more, even more preferably 11.5 mol / kg or more, and particularly preferably 12.0 mol / kg or more. A sum of the hydrogen bonding proton value and (meth)acrylic value of polymerizable compound (a1) of 10.5 mol / kg or more is preferable from the viewpoint of achieving high surface hardness.

[0046] (Ratio of hydrogen-bonding proton value to (meth)acrylic value) The ratio of the hydrogen bonding proton value to the (meth)acrylic value of the polymerizable compound (a1) is not particularly limited, but it is preferably 0.25 or more and 4.0 or less, more preferably 0.35 or more and 3.5 or less, even more preferably 0.45 or more and 3.0 or less, particularly preferably 0.55 or more and 2.5 or less, and most preferably 0.60 or more and 2.0 or less. The above range is preferable from the viewpoint of flexibility and scattering prevention.

[0047] (molecular weight) The molecular weight of the polymerizable compound (a1) is not particularly limited, but is preferably 2000 or less, more preferably 1500 or less, even more preferably 1250 or less, and particularly preferably 1000 or less.

[0048] (Structure of polymerizable compound (a1)) The structure of the polymerizable compound (a1) is not particularly limited, but it is preferably a compound represented by the following general formula (1) or (2).

[0049] [ka]

[0050] In general formula (1), R represents a substituent, X represents C or N, L 1 and L 2 each independently represents a single bond or a divalent linking group, A represents a hydrogen bonding group, Q represents a hydrogen atom or a methyl group, m represents an integer from 0 to 2, and n represents an integer from 2 to 4. However, when X represents C, the sum of m and n is 4, and when X represents N, the sum of m and n is 3. When m represents 2, the two Rs may be the same or different. The plurality of L 1 , A, L 2 , and Q may be the same or different from each other.

[0051] [Chemical formula]

[0052] In general formula (2), Z represents a (k + w)-valent linking group, L 3 and L 4 each independently represents a single bond or a divalent linking group, A represents a hydrogen bonding group, Q represents a hydrogen atom or a methyl group, R represents a substituent, k represents an integer from 2 to 8, and w represents an integer from 0 to 2. The plurality of L 3 , A, L 4 , and Q may be the same or different from each other. When w represents 2, the two Rs may be the same or different.

[0053] In general formula (1), the substituent represented by R is not particularly limited, but examples include alkyl groups (e.g., C1-C10), aryl groups (e.g., C6-C20), cycloalkyl groups (e.g., C3-C10), alkenyl groups (e.g., C2-C10), alkynyl groups (e.g., C2-C10), halogen atoms, alkyloxy groups (e.g., C1-C10), aryloxy groups (e.g., C6-C20), alkyloxycarbonyl groups (e.g., C2-C10), aryloxycarbonyl groups (e.g., C7-C20), alkylcarbonyloxy groups (e.g., C2-C10), arylcarbonyloxy groups (e.g., C7-C20), heterocyclic groups (e.g., C2-C10), hydroxyl groups, cyano groups, nitro groups, etc.

[0054] In general formula (1), L 1 and L 2 When represents a divalent linking group, the divalent linking group is not particularly limited, but for example, alkylene groups (e.g., 1 to 10 carbon atoms), cycloalkylene groups (e.g., 3 to 10 carbon atoms), alkenylene groups (e.g., 2 to 10 carbon atoms), arylene groups (e.g., 6 to 20 carbon atoms), divalent heterocyclic groups (e.g., 2 to 10 carbon atoms), -O-, -SO2-, -CO-, -S-, or divalent linking groups that are combinations of several of these are preferred. 1 and L 2 The substituent may have substituents. There are no particular restrictions on the substituents, and examples include the substituents listed above as the substituent represented by R in general formula (1), a (meth)acrylic group, a (meth)acryloyloxy group, a (meth)acrylamide group, etc.

[0055] In general formula (1), A represents a hydrogen bonding group, and is preferably at least one selected from the group consisting of urethane group, thiourethane group, urea group, thiourea group, amide group, and thioamide group; more preferably at least one selected from the group consisting of urethane group, urea group, and amide group; and even more preferably a urethane group.

[0056] In general formula (1), Q represents a hydrogen atom or a methyl group, and it is preferable that Q represents a hydrogen atom.

[0057] In general formula (1), m represents an integer between 0 and 2, preferably 0 or 1.

[0058] The R in general formula (2) has the same meaning as the R in general formula (1), and the specific examples and preferred ranges are also the same.

[0059] In general formula (2), the k+w valence linking group represented by Z is not particularly limited, but is preferably a chain hydrocarbon group (e.g., 2 to 10 carbon atoms) which may have heteroatoms in the chain, or a cyclic hydrocarbon group (e.g., 2 to 10 carbon atoms) which may have heteroatoms as ring members. Examples of the heteroatoms include oxygen atoms, nitrogen atoms, sulfur atoms, etc., with oxygen atoms being preferred. Substituents may be attached to the chain hydrocarbon group. Substituents may be attached to the carbon atoms of the ring members of the cyclic hydrocarbon group, or oxo groups (=O) may be attached. There are no particular limitations on the substituents, and examples include the substituents listed above as the substituent represented by R in general formula (1), (meth)acrylic groups, (meth)acryloyloxy groups, (meth)acrylamide groups, etc.

[0060] In general formula (2), L 3 and L 4 When represents a divalent linking group, the divalent linking group is not particularly limited, but for example, alkylene groups (e.g., 1 to 10 carbon atoms), cycloalkylene groups (e.g., 3 to 10 carbon atoms), alkenylene groups (e.g., 2 to 10 carbon atoms), arylene groups (e.g., 6 to 20 carbon atoms), divalent heterocyclic groups (e.g., 2 to 10 carbon atoms), -O-, -SO2-, -CO-, -S-, or divalent linking groups that are combinations of several of these are preferred. 3 and L 4 The substituent may have substituents. There are no particular restrictions on the substituents, and examples include the substituents listed above as the substituent represented by R in general formula (1), a (meth)acrylic group, a (meth)acryloyloxy group, a (meth)acrylamide group, etc.

[0061] In general formula (2), A represents a hydrogen bonding group, and is preferably at least one selected from the group consisting of urethane group, thiourethane group, urea group, thiourea group, amide group, and thioamide group; more preferably at least one selected from the group consisting of urethane group, urea group, and amide group; and even more preferably a urea group.

[0062] In general formula (2), Q represents a hydrogen atom or a methyl group, and it is preferable that Q represents a hydrogen atom.

[0063] In general formula (2), k represents an integer between 2 and 8, preferably an integer between 4 and 8.

[0064] Specific examples of polymerizable compounds (a1) are shown below, but the present invention is not limited to these.

[0065] [ka]

[0066] [ka]

[0067] [ka]

[0068] [ka]

[0069] [ka]

[0070] In a different embodiment from those described above, the polymerizable compound (a1) may also preferably be a polyorganosilsesquioxane. Hereinafter, the polymerizable compound (a1) in the case of a polyorganosilsesquioxane will also be referred to as polyorganosilsesquioxane (a1).

[0071] The polyorganosilsesquioxane (a1) preferably has a constituent unit (S1) derived from a hydrolyzable silane compound having a (meth)acrylic group and a constituent unit (S2) derived from a hydrolyzable silane compound having a hydrogen bonding group.

[0072] -Construction unit (S1) derived from a hydrolyzable silane compound having a (meth)acrylic group- The constituent unit (S1) has a (meth)acrylic group. Polyorganosilsesquioxane (a1) may have only one type of constituent unit (S1) or may have two or more types.

[0073] The constituent unit (S1) is preferably a constituent unit represented by the following general formula (S1-1).

[0074] [ka]

[0075] In general formula (S1-1), L 11 represents a single bond or a divalent linking group, R 11 represents a single bond, -NR-, -O-, -C(=O)-, -S-, -SO-, -SO2-, or a divalent linking group obtained by combining these, and R represents a hydrogen atom or a substituted or unsubstituted alkyl group. L 12 represents a single bond, or a substituted or unsubstituted alkylene group. p1 represents a non-negative integer, Q 11 represents a (meth)acrylic group.

[0076] In the general formula (S1-1), "SiO 1.5This represents the structural portion composed of siloxane bonds (Si-O-Si) in polyorganosylsesquioxane. Polyorganosilsesquioxane is a network-type polymer or polyhedral cluster having siloxane constituent units (silsesquioxane units) derived from hydrolyzable trifunctional silane compounds, and can form random structures, ladder structures, cage structures, etc. through siloxane bonding. In the present invention, "SiO 1.5 The structural part represented by "[ ]" may be any of the above structures, but it is preferable that it contains a large amount of ladder structure. By forming a ladder structure, the deformation recovery of the hard coat film can be kept in good condition. The formation of the ladder structure is determined when FT-IR (Fourier Transform Infrared Spectroscopy) is measured at 1020-1050 cm -1 This can be qualitatively confirmed by the presence or absence of absorption originating from the characteristic Si-O-Si stretching of the ladder structure that appears nearby.

[0077] In general formula (S1-1), L 11 When R represents a divalent linking group, the divalent linking group is preferably a divalent linking group consisting of at least one selected from alkylene group, cycloalkylene group, arylene group, -O-, -CO-, -S-, -SO-, -SO2-, and -NR- (where R represents a hydrogen atom or a substituted or unsubstituted alkyl group), and more preferably a divalent linking group consisting of at least one selected from alkylene group, cycloalkylene group, arylene group, and -O-. The alkylene group is preferably an alkylene group having 1 to 10 carbon atoms, for example, a methylene group, methylmethylene group, dimethylmethylene group, ethylene group, i-propylene group, n-propylene group, n-butylene group, n-pentylene group, n-hexylene group, n-decylene group, etc. The arylene group is preferably an arylene group having 6 to 10 carbon atoms, for example, a phenylene group.

[0078] L 11When representing a divalent linking group, it may have substituents, such as hydroxyl groups, carboxyl groups, alkoxy groups, aryl groups, heteroaryl groups, halogen atoms, nitro groups, cyano groups, and silyl groups.

[0079] L 11 The group is preferably an unsubstituted linear alkylene group having 2 to 4 carbon atoms, more preferably an ethylene group or an n-propylene group, and even more preferably an n-propylene group.

[0080] In general formula (S1-1), R 11 represents a single bond, -NR-, -O-, -C(=O)-, -S-, -SO-, -SO2-, or a divalent linking group obtained by combining these. R represents a hydrogen atom or a substituted or unsubstituted alkyl group. For example, divalent linking groups obtained by combining -NR-, -O-, and -C(=O)- include *-NH-C(=O)-**, *-C(=O)-NH-**, *-NH-C(=O)-O-**, *-OC(=O)-NH-**, -NH-C(=O)-NH-, *-C(=O)-O-**, *-OC(=O)-**, etc. * represents L in general formula (S1-1). 11 This represents a bond with L in general formula (S1-1), where ** is L 12 This represents a combination of two things.

[0081] R 11 It is preferably -NH-C(=O)-NH-, *-NH-C(=O)-O-**, *-NH-C(=O)-**, or -O-, and more preferably -NH-C(=O)-NH-, *-NH-C(=O)-O-**, or *-NH-C(=O)-**.

[0082] In general formula (S1-1), L 12 The symbol represents a single bond or an alkylene group. Preferably, the alkylene group has 1 to 10 carbon atoms, and examples include methylene group, methylmethylene group, dimethylmethylene group, ethylene group, i-propylene group, n-propylene group, n-butylene group, n-pentylene group, n-hexylene group, n-decylene group, etc. L 12 When the alkylene group represented by has substituents, the substituents are not particularly limited, but examples include hydroxyl groups, carboxyl groups, alkoxy groups, aryl groups, heteroaryl groups, halogen atoms, nitro groups, cyano groups, silyl groups, and the like. L 12 The group is preferably a linear alkylene group having 1 to 3 carbon atoms, more preferably a methylene group, an ethylene group, an n-propylene group, or a 2-hydroxy-n-propylene group, and even more preferably a methylene group or an ethylene group.

[0083] p1 represents an integer greater than or equal to 0, and if p1 represents 2 or greater, multiple R 11 They may be the same or different, and there may be multiple L 12 They may be the same or different. p1 preferably represents 0, 1, or 2, and more preferably represents 1 or 2. If p1 represents 2, then Q 11 L directly binds 12 -R 11 L 12 It is a single bond, R 11 It is preferable that -O- or -NH- represent the same thing.

[0084] -Constituent unit (S2) derived from a hydrolyzable silane compound having a hydrogen bonding group- The constituent unit (S2) has hydrogen bonding groups. The hydrogen bonding groups are as described above. Polyorganosilsesquioxane (a1) may have only one type of constituent unit (S2) or may have two or more types.

[0085] The constituent unit (S2) is preferably a constituent unit represented by the following general formula (S2-1).

[0086] [ka]

[0087] In general formula (S2-1), L21 represents a single bond or a divalent linking group, R 21 The symbols represent a single bond, -NR-, -O-, -C(=O)-, -S-, -SO-, -SO2-, or a divalent linking group obtained by combining these. R represents a hydrogen atom or an alkyl group. L 22 represents a single bond, or a substituted or unsubstituted alkylene group. p2 represents a non-negative integer, Q 21 This represents a group containing a hydrogen bonding group.

[0088] In the general formula (S2-1), "SiO 1.5 This represents the structural part composed of siloxane bonds (Si-O-Si).

[0089] In general formula (S2-1), L 21 When R represents a divalent linking group, the divalent linking group is preferably a divalent linking group consisting of at least one selected from alkylene group, cycloalkylene group, arylene group, -O-, -CO-, -S-, -SO-, -SO2-, and -NR- (where R represents a hydrogen atom or a substituted or unsubstituted alkyl group), and more preferably a divalent linking group consisting of at least one selected from alkylene group, cycloalkylene group, arylene group, and -O-.

[0090] L 21 When representing a divalent linking group, it may have substituents, such as hydroxyl groups, carboxyl groups, alkoxy groups, aryl groups, heteroaryl groups, halogen atoms, nitro groups, cyano groups, and silyl groups.

[0091] L 21 The group preferably represents an alkylene group, and more preferably an alkylene group having 1 to 10 carbon atoms. Examples include methylene group, methylmethylene group, dimethylmethylene group, ethylene group, i-propylene group, n-propylene group, n-butylene group, n-pentylene group, n-hexylene group, n-decylene group, and the like. L21 Examples of substituents when the alkylene group represented by has substituents include hydroxyl groups, carboxyl groups, alkoxy groups, aryl groups, heteroaryl groups, halogen atoms, nitro groups, cyano groups, and silyl groups. L 21 The group is preferably an unsubstituted linear alkylene group having 2 to 4 carbon atoms, more preferably an ethylene group or an n-propylene group, and even more preferably an n-propylene group.

[0092] In general formula (S2-1), R 21 The '-' represents a single bond, -NR-, -O-, -C(=O)-, -S-, -SO-, -SO2-, or a divalent linking group obtained by combining these. R represents a hydrogen atom or an alkyl group. For example, divalent linking groups obtained by combining -NR-, -O-, and -C(=O)- include *-NH-C(=O)-**, *-C(=O)-NH-**, *-NH-C(=O)-O-**, *-OC(=O)-NH-**, -NH-C(=O)-NH-, *-C(=O)-O-**, *-OC(=O)-**, etc. * represents L in general formula (S2-1). 21 This represents a bond with, where ** is L in general formula (S2-1). 22 This represents a combination of two things.

[0093] R 21 It is preferably -NH-C(=O)-NH-, *-NH-C(=O)-O-**, *-NH-C(=O)-**, or -O-, and more preferably -NH-C(=O)-NH-, *-NH-C(=O)-O-**, or *-NH-C(=O)-**.

[0094] In general formula (S2-1), L 22 The symbol represents a single bond or an alkylene group, and as the alkylene group, an alkylene group having 1 to 10 carbon atoms is preferred, such as a methylene group, methylmethylene group, dimethylmethylene group, ethylene group, i-propylene group, n-propylene group, n-butylene group, n-pentylene group, n-hexylene group, n-decylene group, etc. L 22Examples of substituents when the alkylene group represented by has substituents include hydroxyl groups, carboxyl groups, alkoxy groups, aryl groups, heteroaryl groups, halogen atoms, nitro groups, cyano groups, and silyl groups. L 22 The group is preferably a linear alkylene group having 1 to 3 carbon atoms, more preferably a methylene group, an ethylene group, an n-propylene group, or a 2-hydroxy-n-propylene group, and even more preferably a methylene group or an ethylene group.

[0095] In general formula (S2-1), Q 21 This represents a group containing a hydrogen bonding group. The hydrogen bonding group is as described above. Q 21 It may also be a hydrogen bonding group.

[0096] p2 represents a non-negative integer, and if p2 represents 2 or greater, multiple R 21 They may be the same or different, and there may be multiple L 22 They may be the same or different. p2 preferably represents 0, 1, or 2, and more preferably represents 0 or 1.

[0097] When the polyorganosilsesquioxane (a1) has constituent units (S1) and (S2), the molar ratio of constituent unit (S1) is preferably 10 to 90 mol%, more preferably 20 to 80 mol%, even more preferably 30 to 70 mol%, and particularly preferably 40 to 60 mol% relative to the total number of constituent units.

[0098] When polyorganosilsesquioxane (a1) has constituent units (S1) and (S2), the molar ratio of constituent unit (S2) is preferably 10 to 90 mol%, more preferably 20 to 80 mol%, even more preferably 30 to 70 mol%, and particularly preferably 40 to 60 mol% relative to the total number of constituent units.

[0099] The polyorganosilsesquioxane (a1) may have constituent units (S3) other than constituent units (S1) and (S2), to the extent that it does not affect the effects of the present invention. In the polyorganosilsesquioxane (a1), the molar ratio of constituent unit (S3) is preferably 10 mol% or less, more preferably 5 mol% or less, and even more preferably no constituent unit (S3) is present, relative to the total constituent units.

[0100] The weight-average molecular weight (Mw) of polyorganosilsesquioxane (a1) is preferably 500 to 500,000, more preferably 10,000 to 100,000, and even more preferably 15,000 to 60,000.

[0101] The molecular weight dispersion (Mw / Mn) of polyorganosilsesquioxane (a1) is not particularly limited, but is, for example, 1.00 to 4.00, and preferably 1.10 to 3.70. Mw represents the weight-average molecular weight, and Mn represents the number-average molecular weight.

[0102] The weight-average molecular weight and molecular weight dispersion of polyorganosylsesquioxane (a1) are GPC measurements (polystyrene equivalent) unless otherwise specified. Specifically, the weight-average molecular weight is measured using an HLC-8220 instrument (manufactured by Tosoh Corporation), tetrahydrofuran as the eluent, and TSKgel® G3000HXL + TSKgel® G2000HXL as the column, under conditions of a temperature of 23°C and a flow rate of 1 mL / min, using a differential refractive index (RI) detector.

[0103] The polymer of polymerizable compound (a1) may be a polymer of one type of polymerizable compound (a1), or it may be a polymer (copolymer) of two or more types of polymerizable compounds (a1). Furthermore, (A) may be a copolymer of a polymerizable compound (a1) and another polymerizable compound. Furthermore, polymerization of the polymerizable compound (a1) can be carried out by known methods, and known components (e.g., polymerization initiators) can be used during polymerization.

[0104] The content of polymers derived from polymerizable compound (a1) in polymer (A) is preferably 20 to 100% by mass, more preferably 40 to 100% by mass, and even more preferably 60 to 100% by mass, based on the total mass of the polymer.

[0105] If the protective layer of the present invention contains (A), the content of (A) is preferably 20 to 100% by mass, more preferably 40 to 100% by mass, and even more preferably 60 to 100% by mass, based on the total mass of the protective layer.

[0106] (B) (B) is a compound containing a metal coordination bond. Compounds containing metal coordination bonds include compounds that contain a metal and a ligand capable of forming a metal complex. (B) is preferably a resin containing metal coordination bonds.

[0107] If the protective layer contains (B), it is presumed that a metal complex can be formed by metal coordination bonds, thereby increasing the hardness (pencil hardness) of the protective layer surface. Furthermore, since metal coordination bonds can be reversibly separated and reformed, it is presumed that stress during strain can be released by the separation of metal coordination bonds, and that the protective layer can be given flexibility by reforming the metal bonds after the structural change. In addition, when an impact force is applied, since it can be reversibly separated and reformed, it is presumed that the protective layer can absorb the force in the thickness direction while dispersing the force in the planar direction, thereby providing shatterproof properties.

[0108] (B) is preferably a compound represented by the following formula (B-1) or (B-2).

[0109] [ka]

[0110] [ka]

[0111] In formula (B-1), M represents a metal atom, preferably calcium or magnesium. In formula (B-2), M represents a metal atom, preferably zinc. Each n independently represents any integer greater than or equal to 0, and each m independently represents any integer greater than or equal to 1.

[0112] If the protective layer of the present invention contains (B), the content of (B) is preferably 10 to 100% by mass, more preferably 20 to 100% by mass, even more preferably 30 to 90% by mass, and particularly preferably 30 to 80% by mass, based on the total mass of the protective layer.

[0113] [(C)] (C) is a compound containing a host-guest bond. Examples of compounds containing host-guest bonds include those in which a host molecule encloses a guest molecule. It is presumed that if the protective layer contains (C), the hardness (pencil hardness) of the protective layer surface can be increased. Furthermore, since the host-guest bond can be reversibly separated and reformed, stress during strain can be released by the separation of the host-guest bond, and it is presumed that the protective layer can be given flexibility by the reformation of the host-guest bond after the structural change. In addition, when an impact force is applied, since it can be reversibly separated and reformed, it is presumed that the protective layer can absorb the force in the thickness direction while dispersing the force in the planar direction, thereby providing shatterproof properties. As the host molecule, a compound containing cyclodextrin is preferred. The host molecule may be a polymer obtained by polymerizing at least one compound represented by any of the following formulas (H-1) to (H-3). In the following formulas (H-1) to (H-3), R represents a hydrogen atom, an alkyl group, or an acyl group, preferably a methyl group or an acetyl group. Multiple Rs may be the same or different.

[0114] [ka]

[0115] [ka]

[0116] [ka]

[0117] The guest molecule may be a polymer obtained by polymerizing at least one compound represented by any of the following formulas (G-1) to (G-3).

[0118] [ka]

[0119] (C) may be a mixture of the host molecule and the guest molecule, or a copolymer of the host molecule and the guest molecule, but it is preferable that it be a copolymer of the host molecule and the guest molecule. (C) is preferably a compound comprising a polymer obtained by polymerizing at least one compound represented by any of formulas (H-1) to (H-3) and a polymer obtained by polymerizing at least one compound represented by any of formulas (G-1) to (G-3), and more preferably a compound comprising a polymer obtained by polymerizing formula (H-1) and a polymer obtained by polymerizing formula (G-1). (C) is preferably a polymer obtained by copolymerizing at least one compound represented by any of formulas (H-1) to (H-3) with at least one compound represented by any of formulas (G-1) to (G-3), more preferably a polymer obtained by copolymerizing at least one compound represented by any of formulas (H-1) to (H-3) with at least one compound represented by any of formulas (G-1) to (G-2), and even more preferably a polymer obtained by copolymerizing a compound represented by formula (H-1) with a compound represented by formula (G-1).

[0120] If the protective layer of the present invention contains (C), the content of (C) is preferably 10 to 100% by mass, more preferably 20 to 100% by mass, even more preferably 30 to 90% by mass, and particularly preferably 30 to 80% by mass, based on the total mass of the protective layer.

[0121] [Other ingredients] The protective layer of the present invention may contain components other than those described above, for example, inorganic fine particles, dispersants, leveling agents, lubricants, antifouling agents, antistatic agents, ultraviolet absorbers, antioxidants, and the like.

[0122] The protective layer of the present invention preferably has an elastic modulus of 6 GPa or more and a break elongation of 10% or more, as measured under the following measurement conditions. The measurement conditions are described below. A film A is prepared using a polyimide film as the base material, with a protective layer applied to the base material. Samples (test pieces) with a width of 10 mm and a length of 120 mm are cut from both film A and the base material, and left to stand for at least one hour at a temperature of 25°C and a relative humidity of 60%. Then, using a TENSILON RTF-1210 (A&D Company, Limited), the samples are pulled at a tensile speed of 5 mm / second and a chuck distance (initial gauge distance) of 100 mm, and the relationship between elongation and load is measured. The load acting solely on the protective layer is calculated from the difference between the load on film A at each stage of elongation and the load on the substrate alone, and the modulus of elasticity is determined. The elongation at the time of fracture is defined as the elongation at fracture of film A. Furthermore, a film B is prepared using cycloolefin as the base material and coated with a protective layer in the same manner as described above. Only the protective layer is peeled off from film B, and the elongation at break is determined under the above conditions. The larger of the elongations at break of film A and the protective layer is taken as the elongation at break of the protective layer. The elastic modulus of the protective layer is preferably 8 GPa or higher, more preferably 10 GPa or higher, and even more preferably 12 GPa or higher. The elongation at break of the protective layer is preferably 10% or more, more preferably 15% or more, and even more preferably 23% or more.

[0123] The thickness of the protective layer of the present invention is preferably 10 μm or less, more preferably 1 μm to 8 μm, and even more preferably 2 μm to 7.5 μm.

[0124] The surface roughness Ra of the protective layer is preferably 20 nm or less, more preferably 10 nm or less, even more preferably 5 nm or less, and particularly preferably 2 nm or less. When the surface roughness Ra of the protective layer is low, even if it is made of resin, it can be perceived as glass in appearance, creating a sense of luxury.

[0125] The protective layer of the present invention is used in foldable devices having a glass cover window, and is preferably used in foldable devices in which the thickness of the glass cover window is 100 μm or less. The thickness of the glass cover window of the foldable device to which the protective layer of the present invention is applied is preferably 100 μm or less, more preferably 5 μm to 80 μm, and even more preferably 10 μm to 50 μm.

[0126] The protective layer of the present invention preferably has a total light transmittance of 85% or more in the visible region, more preferably 87.5% or more, even more preferably 90.0% or more, and particularly preferably 92.5% or more.

[0127] [Adhesive layer or bonding layer] The protective layer of the present invention may also have an adhesive layer or bonding layer on at least one surface (i.e., the protective layer of the present invention may be a laminate of the protective layer and the adhesive layer or bonding layer (a protective layer with an adhesive layer, or a protective layer with a bonding layer)). The thickness of the adhesive layer is preferably 1 μm or less, more preferably 0.05 μm or more and 0.9 μm or less, and even more preferably 0.1 μm or more and 0.8 μm or less. If the protective layer of the present invention has an adhesive layer or bonding layer, it is preferable that the adhesive layer or bonding layer be present on only one side of the protective layer, and it is preferable that the adhesive layer or bonding layer be present on the side that faces the glass cover window of the foldable device. There are no particular limitations on the adhesive layer and bonding layer; known adhesive layers and bonding layers can be used.

[0128] [Abrasion resistant layer] The protective layer of the present invention may also have a scratch-resistant layer on at least one surface (i.e., the protective layer of the present invention may be a laminate of a protective layer and a scratch-resistant layer (protective layer with scratch-resistant layer)). The thickness of the scratch-resistant layer is preferably less than 3.0 μm, more preferably 0.1 to 2.0 μm, and even more preferably 0.1 to 1.0 μm. If the protective layer of the present invention has a scratch-resistant layer, it is preferable that the scratch-resistant layer be present on only one side of the protective layer, and that the scratch-resistant layer be present on the side opposite to the side that becomes the glass cover window of the foldable device. It is preferable that the scratch-resistant layer includes at least one of (A) to (C) which can be included in the aforementioned protective layer. (A) to (C) are as previously described.

[0129] If the scratch-resistant layer contains at least one of (A) to (C), the total content of (A) to (C) is preferably 20 to 100% by mass, more preferably 30 to 100% by mass, and even more preferably 40 to 100% by mass, based on the total mass of the scratch-resistant layer.

[0130] Furthermore, the scratch-resistant layer may also include a cured product of a scratch-resistant layer-forming composition containing a radical polymerizable compound (c1).

[0131] (Radical polymerizable compound (c1)) This section explains radical polymerizable compounds (C1) (also called "compound (C1)"). Compound (c1) is a compound having a radical polymerizable group. The radical polymerizable group in compound (c1) is not particularly limited, and generally known radical polymerizable groups can be used. Examples of radical polymerizable groups include polymerizable unsaturated groups, specifically (meth)acryloyl groups, vinyl groups, allyl groups, etc., with (meth)acryloyl groups being preferred. Each of the above groups may have substituents. Compound (c1) is preferably a compound having two or more (meth)acryloyl groups in one molecule, and more preferably a compound having three or more (meth)acryloyl groups in one molecule. The molecular weight of compound (c1) is not particularly limited; it may be a monomer, an oligomer, or a polymer.

[0132] [Foldable devices] The foldable device of the present invention is a foldable device having a glass cover window and a protective layer provided on the cover window, wherein the protective layer is the protective layer of the present invention as described above. A foldable device is a device that employs a flexible display whose screen can be reshaped, allowing the device body (display) to be folded by utilizing the deformability of the display screen. Examples of foldable devices include organic electroluminescent devices. A cover window is a component installed to protect the display screen of a foldable device, and is typically a sheet of glass (glass substrate).

[0133] The thickness of the glass cover window of the foldable device of the present invention is preferably 100 μm or less, more preferably 5 μm to 80 μm, and even more preferably 10 μm to 50 μm.

[0134] The foldable device of the present invention may also have an adhesive layer or bonding layer between the protective layer and the cover window. The thickness of the adhesive layer is preferably 1 μm or less, more preferably 0.05 μm or more and 0.9 μm or less, and even more preferably 0.1 μm or more and 0.8 μm or less. There are no particular limitations on the adhesive layer and bonding layer; known adhesive layers and bonding layers can be used.

[0135] The foldable device of the present invention may also have a scratch-resistant layer on the surface of the protective layer opposite to the cover window side. The thickness of the scratch-resistant layer is preferably less than 3.0 μm, more preferably 0.1 to 2.0 μm, and even more preferably 0.1 to 1.0 μm.

[0136] It is preferable that the scratch-resistant layer includes at least one of (A) to (C) which can be included in the aforementioned protective layer. (A) to (C) are as previously described.

[0137] If the scratch-resistant layer contains at least one of (A) to (C), the total content of (A) to (C) is preferably 20 to 100% by mass, more preferably 30 to 100% by mass, and even more preferably 40 to 100% by mass, based on the total mass of the scratch-resistant layer.

[0138] Furthermore, the scratch-resistant layer may also include a cured product of a scratch-resistant layer-forming composition containing a radical polymerizable compound (c1). The radical polymerizable compound (c1) is as described above. [Examples]

[0139] The present invention will be described in more detail below with reference to examples, but the scope of the present invention shall not be limited thereto.

[0140] The structures of the compounds used in the examples and comparative examples are shown below. (A-1) and (SQ2) are polymerizable compounds (a1). In the following structural formula, "SiO 1.5 " represents a silsesquioxane unit. In each polymer's constituent units, the composition ratio of each constituent unit is expressed as a molar ratio. Mw represents the weight-average molecular weight.

[0141] [ka]

[0142] [ka]

[0143] [ka]

[0144] [ka]

[0145] [ka]

[0146] [Examples 1-9, 15, 16, Comparative Examples 4-5] <Preparation of curable composition> (Curable composition HC-1~HC-10) The content of each component was adjusted as shown in Table 1 below, and the mixture was added to a mixing tank and stirred. The resulting composition was filtered through a polypropylene filter with a pore size of 0.45 μm to prepare curable compositions HC-1 to HC-10. The values ​​in Table 1 below represent the amount of each component added, and the unit is parts by mass.

[0147] [Table 1]

[0148] The compounds used are as follows: Irg.127 is made by BASF. A-TMMT: Pentaerythritol tetraacrylate (manufactured by Shin-Nakamura Chemical Industry Co., Ltd.) DPCA-20: KAYARAD DPCA-20 (manufactured by Nippon Kayaku Co., Ltd.) DPCA-120: KAYARAD DPCA-120 (manufactured by Nippon Kayaku Co., Ltd.) KBM-5103 (manufactured by Shin-Etsu Chemical Co., Ltd.) RS-90: Lubricant, manufactured by DIC Corporation (solid content concentration 10% by mass)

[0149] [(SQ2) synthesis] 300 mmol (53.8 g) of 3-aminopropyltrimethoxysilane and 166 g of methyl isobutyl ketone were mixed. This solution was cooled to below 5°C, and 300 mmol (42.3 g) of 2-acryloyloxyethyl isocyanate was added dropwise. After the reaction, the mixture was allowed to rise to room temperature. Then, 300 mmol (70.0 g) of acrylamide 3-(trimethoxysilyl)propyl, 7.39 g of triethylamine, and 434 g of acetone were mixed, and 73.9 g of pure water was added dropwise over 30 minutes using a dropping funnel. The reaction solution was heated to 50°C, and the polycondensation reaction was carried out for 10 hours. Subsequently, the reaction solution was cooled and neutralized with 12 mL of 1 mol / L hydrochloric acid aqueous solution. After adding 600 g of 1-methoxy-2-propanol, the solution was concentrated under conditions of 30 mmHg and 50°C to obtain a clear liquid product (SQ2) as a propylene glycol monomethyl ether (PGME) solution with a solid content of 35% by mass. 1 mmHg is equivalent to 101325 / 760 Pa.

[0150] (B-1-Ca) was synthesized using the method described in Appl.Mater.Interfaces 2016, 8, 19047-19053. In this synthesis, the molar ratio of dopamine acrylamide to butyl acrylate was 80:20, and calcium was used as the metal M. (B-1-Ca) is a compound containing a metal coordination bond.

[0151] The (H-1-m) / (G-1) elastomer was synthesized using the method described in Macromolecules 2019, 52, 2659-2668, with a molar ratio of (H-1-m) to (G-1) of 50:50. (H-1-m) is a compound in which the R group of the aforementioned (H-1) is a methyl group. (H-1-m) / (G-1) elastomers are compounds that contain a host-guest bond.

[0152] (Manufacturing of protective layer) On glass substrates (manufactured by Nippon Electric Glass Co., Ltd., G-Leaf) with the thicknesses shown in Tables 2 and 3 below, the curable compositions shown in Tables 2 and 3 below were applied using a wire bar so that the film thickness after curing was as shown in Tables 2 and 3 below, thereby forming a protective layer coating on the glass substrate. Next, the protective coating was dried at 120°C for 5 minutes, and then irradiated with an air-cooled mercury lamp at 25°C and an oxygen concentration of 100 ppm (parts per million) with an irradiation dose of 300 mJ / cm². 2 The sample was irradiated with ultraviolet light. In this way, the protective layer coating was cured, and a protective layer was formed on the glass substrate. Samples for Examples 1-9, 15, 16, and Comparative Examples 4-5 were prepared in this manner (see Figure 1).

[0153] [Table 2]

[0154] [Table 3]

[0155] [Comparative Example 1] A 50 μm thick glass substrate (G-Leaf, manufactured by Nippon Electric Glass Co., Ltd.) was used as the sample for Comparative Example 1 (without protective layer) (see Figure 4).

[0156] [Examples 10-12] A protective layer coating was formed on a glass substrate (manufactured by Nippon Electric Glass Co., Ltd., G-Leaf) of the thickness shown in Table 4 below. The curable composition shown in Table 4 below was applied using a wire bar so that the film thickness after curing was as shown in Table 4 below. Next, the protective coating was dried at 120°C for 5 minutes, and then irradiated at 60 mJ / cm² using an air-cooled mercury lamp at 25°C and an oxygen concentration of 100 ppm (parts per million). 2 Ultraviolet light was irradiated onto the glass substrate. In this way, the protective layer coating was cured, and a protective layer was formed on the glass substrate.

[0157] [Table 4]

[0158] (Scratch resistant layer forming composition SR-1) The components were added to a mixing tank in the composition described below, stirred, and filtered through a polypropylene filter with a pore size of 0.4 μm to obtain composition SR-1 for forming a scratch-resistant layer. A-TMMT 26.2 parts by mass DPCA-30 7.1 parts by mass Irgacure 127 1.0 parts by mass Conductive compound A 3.2 parts by mass RS-90 3.5 parts by mass Methyl ethyl ketone 50.4 parts by mass

[0159] The compounds used in the scratch-resistant layer-forming composition are as follows: A-TMMT: Pentaerythritol tetraacrylate (manufactured by Shin-Nakamura Chemical Industry Co., Ltd.) DPCA-30: KAYARAD DPCA-30 (manufactured by Nippon Kayaku Co., Ltd.) RS-90: Lubricant, manufactured by DIC Corporation (solid content concentration 10% by mass)

[0160] [ka]

[0161] (Method for synthesizing conductive compound A) 58.25 g of ethanol was placed in a 500 ml three-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube, and the temperature was raised to 70°C. Then, a mixed solution consisting of 62.14 g (299.18 mmol) of trimethyl-2-methacroyloxyethylammonium chloride (80% aqueous solution), 20.00 g (118.88 mmol) of cyclohexyl methacrylate, 30.00 g (18.07 mmol) of Bremmer PSE1300 (manufactured by NOF Corporation), 167.90 g of ethanol, and 24.50 g of azobisisobutyronitrile was added dropwise at a constant rate so that the addition was completed in 3 hours. After the dropwise addition was complete, a mixed solution of 0.40 g of azobisisobutyronitrile and 19.10 g of ethanol was added, and stirring was continued for a further 3 hours. Then, the temperature was raised to 78.5°C and stirring was continued for a further 8 hours to obtain 360.00 g of polymer ethanol solution (solid content concentration 28% by mass).

[0162] (Scratch resistant layer forming composition SR-2) The components were added to a mixing tank in the composition described below, stirred, and filtered through a polypropylene filter with a pore size of 0.4 μm to obtain composition SR-2 for forming a scratch-resistant layer. A-TMMT 16.7 parts by mass (A-1) 16.7 parts by mass Irgacure 127 1.0 parts by mass Conductive compound A 3.2 parts by mass RS-90 3.5 parts by mass Methyl ethyl ketone 50.4 parts by mass

[0163] (Manufacturing of a protective layer with a scratch-resistant coating) In Examples 10-12, the scratch-resistant layer-forming compositions shown in Table 5 below were applied to the surface of the protective layer opposite to the glass substrate side using a die coater, so that the cured film thickness was 1 μm. Next, the resulting laminate was dried at 120°C for 1 minute, and then subjected to 25°C, oxygen concentration of 100 ppm, and illuminance of 60 mW / cm². 2 , irradiation amount 600mJ / cm 2Irradiate with ultraviolet rays, and further use an air-cooled mercury lamp under the conditions of 100 °C and an oxygen concentration of 100 ppm, with an illuminance of 60 mW / cm 2 , and irradiate with ultraviolet rays with an irradiation dose of 600 mJ / cm 2 to form a protective layer with a scratch-resistant layer. Samples of Examples 10 to 12 were prepared in this way (see Figure 2).

[0164] [Table 5]

[0165] [Example 13] On a cycloolefin substrate, the curable composition HC-5 was bar-coated using a wire bar so that the film thickness after curing was 5 μm. Next, after drying the protective layer coating film at 120 °C for 1 minute, using an air-cooled mercury lamp under the conditions of 25 °C and an oxygen concentration of 100 ppm (parts per million), an irradiation dose of 300 mJ / cm 2 of ultraviolet rays was irradiated to form a protective layer. Next, Aron Alpha (registered trademark) (manufactured by Toagosei Co., Ltd.) was applied onto a glass substrate (manufactured by Nippon Electric Glass Co., Ltd., G-Leaf) with a thickness of 50 μm so that the thickness was 10 μm, and it was laminated with a roller so as to contact the protective layer formed on the cycloolefin substrate, and left for 24 hours. Then, the cycloolefin substrate was peeled off from the protective layer, and a sample of Example 13 was prepared (see Figure 3).

[0166] [Example 14] A sample was prepared in the same manner as in Example 13, except that the thickness of Aron Alpha (registered trademark) (manufactured by Toagosei Co., Ltd.) was 1 μm.

[0167] [Comparative Example 2] On a 40-μm-thick PET (polyethylene terephthalate) substrate, the curable composition HC-7 was bar-coated using a wire bar so that the film thickness after curing was 5 μm. Next, after drying the protective layer coating film at 120 °C for 1 minute, using an air-cooled mercury lamp under the conditions of 25 °C and an oxygen concentration of 100 ppm (parts per million), an irradiation dose of 300 mJ / cm 2Ultraviolet rays were irradiated to form a protective layer. The obtained PET substrate with the protective layer was bonded to a 50-μm-thick glass substrate (manufactured by Nippon Electric Glass Co., Ltd., G-Leaf) using an adhesive with a thickness of 30 μm. Thus, a sample of Comparative Example 2 was prepared (see FIG. 5).

[0168] [Comparative Example 3] On a 40-μm-thick PET substrate, the curable composition HC-7 was bar-coated using a wire bar so that the film thickness after curing would be 5 μm. Next, after drying the protective layer coating film at 120°C for 1 minute, it was irradiated with ultraviolet rays having an irradiation amount of 300 mJ / cm 2 to form a protective layer. A 1-μm-thick Aron Alpha (registered trademark) (manufactured by Toagosei Co., Ltd.) was applied on a 50-μm-thick glass substrate, and it was bonded to the PET substrate side of the PET substrate with the protective layer using a roller so as to be in contact, and left for 24 hours to prepare a sample of Comparative Example 3 (see FIG. 5).

[0169] [Evaluation] The samples of each of the manufactured examples and comparative examples were evaluated by the following method. The evaluation results are shown in Tables 6 to 7.

[0170] (Elastic modulus and elongation at break) The elastic modulus and elongation at break are the elastic modulus and elongation at break measured under the above-described measurement conditions.

[0171] (Pencil hardness) Pencil hardness was evaluated according to JIS (Japanese Industrial Standards) K5400. The protective layer (laminated structure including the glass substrate and protective layer) of each example and comparative example was conditioned at 25°C and 60% relative humidity for 2 hours. Then, five different locations on the surface of the protective layer (the surface of the scratch-resistant layer for samples with a scratch-resistant layer, and the surface of the glass substrate for samples without a protective layer) were scratched with a 750g load using test pencils of H to 9H as specified in JIS S 6006. Afterward, the hardness of the pencil with the highest hardness among those with 0 to 2 visible scratches was used as the evaluation result. In pencil hardness, a higher number before "H" indicates higher and more desirable hardness. Pencil hardness was evaluated according to the following criteria. A: 5H or more, B: 4H or more but less than 5H, C: 3H or more but less than 4H, D: H or more but less than 3H, E: Less than H

[0172] (Bending resistance) Each sample (a laminate including a glass substrate and a protective layer) was evaluated using the method described in JIS-K-5600-5-1, General Test Methods for Coatings - Flexural Resistance (Cylindrical Mandrel Method). After storing each sample for 1 hour under conditions of 25°C and 55% relative humidity, the coated surface (protective layer or scratch-resistant layer) was wrapped around mandrels with diameters (Φ) of 2, 3, 4, 5, 6, 8, 10, 12, 14, and 16 mm (glass substrate facing inward). The occurrence of cracks was observed, and the evaluation was based on the smallest mandrel diameter in which no cracks occurred. A smaller mandrel diameter (Φ) indicates better flexural resistance, while the occurrence of cracks under larger diameter conditions indicates poorer flexural resistance. The presence or absence of cracks was determined visually. Flexural resistance was evaluated according to the following criteria. A: 4mmΦ or less, B: Larger than 4mmΦ and 8mmΦ or less, C: Larger than 8mmΦ and 12mmΦ or less, D: Larger than 12mmΦ

[0173] (smoothness) For the surface of the protective layer (the surface of the scratch-resistant layer for samples with a scratch-resistant layer, and the surface of the glass substrate for samples without a protective layer), the surface roughness Ra was measured using Vertscan2.0 (manufactured by Ryoka Systems Co., Ltd.) at a field of view of 3724 μm × 4965 μm with a lens magnification of ×2.5, a barrel magnification of ×0.5, and Wave mode. The surface roughness Ra is preferably 20 nm or less, more preferably 10 nm or less, even more preferably 5 nm or less, and particularly preferably 2 nm or less.

[0174] (Shatterproof) Samples of the examples and comparative examples, measuring 5 cm x 5 cm, were placed on a smooth surface, and a 100 g iron ball was dropped from a height of 30 cm. The degree of scattering of the samples was evaluated using the following index. Here, the degree of scattering was defined as the ratio (%) of the mass of the detached portion after evaluation to the mass of the sample before evaluation. Degree of scattering (= 100 × Mass of detached portion (g) / Mass before evaluation (g)) A: Less than 20%, B: 20% to less than 40%, C: 40% to less than 60%, D: 60% to less than 80%, E: 80% or more

[0175] (Scratch resistance) The surface of the protective layer of each sample (a laminate including a glass substrate and a protective layer) was subjected to a rubbing test using a rubbing tester under the following conditions (the surface of the scratch-resistant layer for samples with a scratch-resistant layer, and the surface of the glass substrate for samples without a protective layer) to determine the scratch resistance. Evaluation environment conditions: 25°C, relative humidity 60% Abrasive material: Steel wool (manufactured by Nippon Steel Wool Co., Ltd., Grade No. #0000) Wrap the band around the rubbing tip (2cm x 2cm) of the tester that comes into contact with the sample, and secure it in place. Distance traveled (one way): 13cm Rubbing speed: 13 cm / second Load: 1 kg / cm 2 Tip contact area: 1cm x 1cm Number of rubs: 10 back-and-forth strokes, 100 back-and-forth strokes, 1000 back-and-forth strokes An oil-based black ink was applied to the surface of the glass substrate on the side opposite to the rubbed surface of the sample after the test, and visually observed with reflected light to measure and evaluate the number of rubbing times when scratches occurred on the portion that had been in contact with the steel wool. A: No scratches occur when rubbed 1000 times back and forth. B: No scratches occur when rubbed 100 times back and forth, but scratches occur when rubbed 1000 times back and forth. C: No scratches occur when rubbed 10 times back and forth, but scratches occur when rubbed 100 times back and forth. D: Scratches occur when rubbed 10 times back and forth.

[0176]

Table 6

[0177]

Table 7

[0178] Tables 6 to 7 also show the proton value of hydrogen bonding and the (meth)acrylic value for the polymerizable compounds used in Examples 1 to 4, 7 to 11, 13, 14, and Comparative Examples 2 to 5. For (SQ2) in Examples 1 to 3, for (A-1) in Examples 4, 7 to 11, 13, 14, for DPCA-20 in Comparative Examples 2, 3, 5, and for DPCA-120 in Comparative Example 4, the proton value of hydrogen bonding and the (meth)acrylic value are described respectively. As shown in Tables 6 to 7, the samples of Examples 1 to 16 were excellent in smoothness, pencil hardness, and anti-scattering properties.

Industrial Applicability

[0179] According to the present invention, there can be provided a protective layer that can be used for a foldable device having a glass cover window, the protective layer being excellent in smoothness, pencil hardness, and anti-scattering properties, and a foldable device having the above protective layer.

[0180] Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. This application is based on Japanese Patent Application No. 2021-062153 filed on March 31, 2021, and Japanese Patent Application No. 2021-205521 filed on December 17, 2021, the contents of which are incorporated herein by reference. [Explanation of Symbols]

[0181] 1. Glass substrate 2 protective layer 3 Scratch resistant layer 4. Adhesive layer or bonding layer 5. PET (polyethylene terephthalate) substrate 10 Samples of Examples 1-9, 15, 16, and Comparative Examples 4-5 20 Samples from Examples 10-12 30 Samples from Examples 13-14 40 Sample of Comparative Example 1 50 Samples of Comparative Examples 2-3

Claims

1. A protective layer comprising at least one of the following (A) to (C). (A) A polymer of a polymerizable compound having one or more hydrogen-bonding groups and three or more (meth)acrylic groups in the molecule, with a hydrogen-bonding proton value of 3.5 mol / kg or more and a (meth)acrylic value of 4.8 mol / kg or more. (B) Compounds containing a metal coordination bond, represented by the following formula (B-1) or (B-2) (C) A compound comprising a host-guest bond, comprising a polymer obtained by polymerizing at least one compound represented by any of the following formulas (H-1) to (H-3) as the host molecule, and comprising a polymer obtained by polymerizing at least one compound represented by any of the following formulas (G-1) to (G-3) as the guest molecule. 【Chemistry 1】 【Chemistry 2】 In formula (B-1), M represents a metal atom. In equation (B-2), M represents a metal atom. Each n independently represents any integer greater than or equal to 0, and each m independently represents any integer greater than or equal to 1. In the following formulas (H-1) to (H-3), R represents a hydrogen atom, an alkyl group, or an acyl group. Multiple Rs may be the same or different. 【Transformation 3】 【Chemistry 4】 【Transformation 5】 【Transformation 6】

2. The protective layer according to claim 1, wherein the elastic modulus of the protective layer is 6 GPa or more and the elongation at break is 10% or more.

3. The protective layer according to claim 2, wherein the elongation at break of the protective layer is 23% or more.

4. The protective layer according to any one of claims 1 to 3, wherein the protective layer comprises (A), and the hydrogen bonding group of (A) is at least one selected from the group consisting of a hydroxyl group, a carboxyl group, a urethane group, an amino group, an amide group, a urea group, a boronic acid group, a thiourethane group, a thioamide group, and a thiourea group.

5. The protective layer according to any one of claims 1 to 4, wherein the thickness of the protective layer is 10 μm or less.

6. The protective layer according to any one of claims 1 to 5, wherein at least one surface of the protective layer has an adhesive layer or bonding layer with a thickness of 1 μm or less.

7. The protective layer according to any one of claims 1 to 6, wherein at least one surface of the protective layer has a scratch-resistant layer.

8. The protective layer according to claim 7, wherein the scratch-resistant layer comprises at least one of the following (A) to (C). (A) A polymer of a polymerizable compound having one or more hydrogen-bonding groups and three or more (meth)acrylic groups in the molecule, with a hydrogen-bonding proton value of 3.5 mol / kg or more and a (meth)acrylic value of 4.8 mol / kg or more. (B) Compounds containing metal coordination bonds (C) Compounds containing host-guest bonds

9. A foldable device having a glass cover window and a protective layer provided on the cover window, A foldable device wherein the protective layer is the protective layer described in any one of claims 1 to 5.

10. The foldable device according to claim 9, wherein the thickness of the cover window is 100 μm or less.

11. The foldable device according to claim 9 or 10, further comprising an adhesive layer or bonding layer with a thickness of 1 μm or less between the protective layer and the cover window.

12. The foldable device according to any one of claims 9 to 11, wherein the protective layer has a scratch-resistant layer on the surface opposite to the cover window side.

13. The foldable device according to claim 12, wherein the scratch-resistant layer includes at least one of the following (A) to (C). (A) A polymer of a polymerizable compound having one or more hydrogen-bonding groups and three or more (meth)acrylic groups in the molecule, with a hydrogen-bonding proton value of 3.5 mol / kg or more and a (meth)acrylic value of 4.8 mol / kg or more. (B) Compounds containing metal coordination bonds (C) Compounds containing host-guest bonds

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