Photocurable composition for forming micro-coating layer, micro-coating layer, and display device and method for producing same

Abstract

The invention provides a photocurable composition for forming a micro-coating layer, a micro-coating layer, a display device and a manufacturing method thereof. The photocurable composition can obtain a cured film with high tensile elastic coefficient, high elongation at break and excellent adhesion. A photocurable composition for forming a micro-coating layer that is disposed in a bending region connecting a display unit having a pixel array layer and a drive unit that drives the pixel array layer is a photocurable composition containing an N-substituted (meth) acrylamide, a compound represented by formula (1), and a radical polymerization initiator. In formula (1), R1 and R2 independently represent a hydrogen atom or a methyl group. And R3 represents an alkanediyl group having 2 to 6 carbon atoms. And n is an integer from 2 to 15. CH2-CR1-CO-O-(R3-O) n-CO-CR2-CCH2... (1)

Description

Technical Field

[0001] This invention relates to a photocurable composition for forming microcoatings, microcoatings, display devices, and methods for manufacturing the same. Background Technology

[0002] Organic electroluminescence (OLED) display devices and liquid crystal display devices, among other types, are widely used as touchscreen devices, such as smartphones or personal computers (PCs), or as multi-monitor setups connecting multiple devices. Furthermore, in display devices, efforts are being made to achieve narrow bezels in order to further expand the display area or movable area. As one method for achieving narrow bezels in display devices, in the past, in flexible displays where resin films were primarily used as the substrate, attempts were made to place the driving portion, which is usually located on the outer periphery of the display area, on the back side of the display area (for example, see Patent Document 1 or Patent Document 2).

[0003] Patent Documents 1 and 2 disclose a liquid crystal panel comprising a display area having a pixel array layer and a driving section connected to the pixel array layer via wiring. The driving section is positioned on the back side of the display area by bending the region connecting the display area and the driving section. In this type of drive section folding-back display device, a micro-coating (resin layer in Patent Document 2) is provided on the outer surface of the bent region connecting the display area and the driving section. The micro-coating protects the wiring disposed in the bent region from external influences or alleviates the stress applied to the bent region.

[0004] [Existing Technical Documents]

[0005] [Patent Literature]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2019-029359

[0007] [Patent Document 2] Japanese Patent Application Publication No. 2018-194632 Summary of the Invention

[0008] [The problem the invention aims to solve]

[0009] In manufacturing a display device in which the driving unit is positioned on the back side of the display area, firstly, the display unit having a pixel array layer and the driving unit having a pixel array layer are arranged horizontally in a separate state. After forming a microcoating between the display unit and the driving unit, the area containing the microcoating is bent, thereby positioning the driving unit on the back side of the display unit. Therefore, the microcoating is required to have physical properties that can withstand bending when the driving unit is positioned on the back side of the display unit; specifically, it must have a high tensile elastic modulus, exhibit high elongation at break, and excellent adhesion to the substrate.

[0010] The present invention was made in view of the aforementioned problems, and one of its objectives is to provide a photocurable composition for forming microcoatings, which can produce a cured film with a high tensile elastic modulus, high elongation at break, and excellent adhesion. Another objective is to provide a display device that can achieve narrow bezels while suppressing product yield reduction.

[0011] [Technical means to solve the problem]

[0012] According to the present invention, the following photocurable composition for forming microcoatings, microcoatings, display devices, and methods for manufacturing display devices can be provided.

[0013] [1] A photocurable composition for forming a microcoating is a photocurable composition for forming a microcoating disposed on the outer surface of a curved region connecting a display portion having a pixel array layer and a drive portion for driving the pixel array layer. The photocurable composition for forming a microcoating contains N-substituted (meth)acrylamide, a compound represented by the following formula (1), and a free radical polymerization initiator.

[0014] CH2=CR 1 -CO-O-(R 3 -O) n -CO-CR 2 =CH2···(1)

[0015] (In equation (1), R) 1 and R 2 Each can be a hydrogen atom or a methyl group, independent of the others. R 3 It is an alkyldiyl group with 2 to 6 carbon atoms. n is an integer from 2 to 15. Multiple R in the formula... 3 (Same or different)

[0016] [2] The photocurable composition for forming microcoatings according to [1], wherein n in formula (1) is 4 or more.

[0017] [3] The photocurable composition for forming microcoatings according to [1] or [2] further contains a (meth)acrylate compound having a phosphate group.

[0018] [4] According to the photocurable composition for forming microcoatings described in [3], the content of the (meth)acrylate compound having a phosphate group is 1 to 20 parts by mass relative to 100 parts by mass of the total amount of polymerizable compounds in the composition.

[0019] [5] A photocurable composition for forming a microcoating according to any one of [1] to [4], wherein the content of the N-substituted (meth)acrylamide is 20 to 80 parts by mass relative to 100 parts by mass of the total amount of polymerizable compounds in the composition.

[0020] [6] A photocurable composition for forming a microcoating according to any one of [1] to [5], wherein the content of the compound represented by formula (1) is 5 to 60 parts by mass relative to 100 parts by mass of the total amount of polymeric compound in the composition.

[0021] [7] A photocurable composition for forming a microcoating according to any one of [1] to [6], wherein the content of the free radical polymerization initiator is 0.2 to 15 parts by mass relative to 100 parts by mass of the total amount of polymerizable compounds in the composition.

[0022] [8] The light-curing composition for forming a microcoating according to any one of [1] to [7], wherein the viscosity measured using an E-type viscometer at 25°C and 20 rpm is 1.0 mPa·s to 35.0 mPa·s.

[0023] [9] A photocurable composition for forming a microcoating according to any one of [1] to [8], wherein the coating is formed under an illuminance of 1000 mW / cm². 2 And the cumulative light intensity is 1000 mJ / cm 2 Under certain conditions, a hardened film with a thickness of 50 μm obtained by irradiating the photocurable composition with ultraviolet light of wavelength 395 nm has a tensile elastic modulus of 0.8 GPa or higher.

[0024]

[10] A photocurable composition for forming a microcoating according to any one of [1] to [9], wherein the coating is formed under an illuminance of 1000 mW / cm². 2 And the cumulative light intensity is 1000 mJ / cm 2 Under certain conditions, the elongation at break of a 50 μm thick hardened film obtained by irradiating the photocurable composition with ultraviolet light of wavelength 395 nm is 20% or more.

[0025]

[11] A microcoating formed by curing a photocurable composition for forming a microcoating according to any one of [1] to

[10] .

[0026]

[12] A display device includes: a display section having a pixel array layer; a driving section for driving the pixel array layer; and a bending region connecting the display section and the driving section, the bending region including a microcoating formed by a photocurable composition for forming a microcoating according to any one of [1] to

[10] .

[0027]

[13] A method for manufacturing a display device, comprising a display portion having a pixel array layer and a driving portion for driving the pixel array layer, the method comprising: a step of arranging the display portion and the driving portion in a horizontal direction while separating them; a step of coating a substrate containing a region between the display portion and the driving portion with a photocurable composition for forming a microcoating according to any one of [1] to

[10] ; a step of obtaining a microcoating by irradiating the photocurable composition for forming a microcoating on the substrate with radiation and curing it; and a step of forming a curved region connecting the display portion and the driving portion by bending a region containing the microcoating.

[0028]

[14] The method of manufacturing the display device according to

[13] wherein the photocurable composition for forming the microcoating is applied by inkjet coating.

[0029] [The effects of the invention]

[0030] This invention provides a microcoating exhibiting high tensile elastic modulus, high elongation at break, and excellent adhesion. Furthermore, by fabricating a display device incorporating this microcoating, narrow bezels in the display panel can be achieved while suppressing product yield reduction. Attached Figure Description

[0031] Figure 1 This is a diagram showing a schematic structure of a display device with the drive unit positioned on the rear side of the display unit.

[0032] Figure 2 This is a diagram showing a schematic structure of a display device in which the driving unit is positioned on the rear side of the display unit.

[0033] Figure 3 It is an enlarged cross-sectional view of the section containing the curved area.

[0034] Explanation of icon numbers

[0035] 10: Display device

[0036] 11: Pixel Array Layer

[0037] 12: Display Section

[0038] 12a, 13a: Surface

[0039] 13: Drive Unit

[0040] 14, 15: Substrate

[0041] 16: Driver IC

[0042] 17: Wiring

[0043] 18: Circuit board

[0044] 19: Microcoating

[0045] LA: Turnaround Line

[0046] SB: Non-display area

[0047] SC: Wiring Area

[0048] SD: Curved area Detailed Implementation

[0049] The following provides a detailed description of matters related to the implementation method. Furthermore, in this specification, the numerical range indicated by “~” refers to the values ​​before and after the “~” as the lower and upper limits.

[0050] In this specification, "hydrocarbon group" refers to a group comprising chain-like hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups. "Chain-like hydrocarbon group" refers to a straight-chain hydrocarbon group or a branched hydrocarbon group that consists only of a chain structure and does not contain a cyclic structure. Chain-like hydrocarbon groups can be saturated or unsaturated. "Alicyclic hydrocarbon group" refers to a hydrocarbon group that contains only an alicyclic hydrocarbon structure as its ring structure and does not contain an aromatic ring structure. Alicyclic hydrocarbon groups do not necessarily need to consist solely of an alicyclic hydrocarbon structure; they may also include groups with a chain structure in a portion of their structure. "Aromatic hydrocarbon group" refers to a hydrocarbon group that contains an aromatic ring structure as its ring structure. Aromatic hydrocarbon groups do not necessarily need to consist solely of an aromatic ring structure; they may also include a chain structure or an alicyclic hydrocarbon structure in a portion of their structure. "Organic group" refers to a group of atoms formed by removing any hydrogen atoms from a carbon-containing compound (i.e., an organic compound). "Polymerizable compound" refers to a compound having a polymerizable group that exhibits polymerizability upon exposure to radiation.

[0051] Photocurable Compositions

[0052] The photocurable composition disclosed herein (hereinafter also referred to as "the composition") is a composition for forming a microcoating disposed on a display device. The microcoating is disposed on a curved portion containing wiring extending outward from the display portion of the display device (preferably a flexible display) and is a resin layer that protects the wiring. In various display devices such as smartphones or input panel PCs, the drive portion, which is normally disposed on the outer periphery of the display portion, is disposed on the back side of the display portion, thereby enabling a narrow bezel design for the display device.

[0053] This composition contains the following components (A), (B), and (C).

[0054] Ingredient (A): N-substituted (meth)acrylamide

[0055] Component (B): The compound represented by the following formula (1)

[0056] CH2=CR 1 -CO-O-(R 3 -O) n -CO-CR 2 =CH2···(1)

[0057] (In equation (1), R) 1 and R 2 Each can be a hydrogen atom or a methyl group, independent of the others. R 3 It is an alkyldiyl group with 2 to 6 carbon atoms. n is an integer from 2 to 15. Multiple R in the formula... 3 (Same or different)

[0058] Component (C): Free radical polymerization initiator

[0059] The N-substituted (meth)acrylamide and the compound represented by formula (1) contained in this composition are polymerizable compounds that polymerize by providing light in the presence of a free radical polymerization initiator, having an ethylene unsaturated group (more specifically, a (meth)acryloyl group). Hereinafter, the components contained in this composition, and other components to be formulated as needed, will be described in detail, and the physical properties of this composition will be explained. Furthermore, unless otherwise specifically mentioned, each component may be used alone or in combination of two or more.

[0060] <Ingredient (A): N-substituted (meth)acrylamide>

[0061] N-substituted (meth)acrylamides possess (meth)acrylamide (CH2=CR) 4 -CO-NH2,R 4At least one hydrogen atom bonded to the nitrogen atom in a (hydrogen atom or methyl) group is removed, resulting in a partial structure in which the nitrogen atom is bonded to the organic group. Specific examples of N-substituted (meth)acrylamides include compounds represented by the following formula (2).

[0062] CH2=CR 4 -CO-N(R 5 (R) 6 (2)

[0063] (In equation (2), R) 4 It can be a hydrogen atom or a methyl group. R 5 and R 6 Chinese R 5 It is a monovalent organic group and R 6 It can be a hydrogen atom or a monovalent organic group, or it can represent R. 5 and R 6 Combine with R 5 and R 6 (The nitrogen-containing heterocyclic structure formed by the bonded nitrogen atoms)

[0064] In equation (2), R 5 Or R 6 The monovalent organic group represented may include substituted or unsubstituted monovalent hydrocarbon groups having 1 to 20 carbon atoms, wherein the carbon-carbon bonds in the hydrocarbon group contain -O-, -S-, -CO-, -COO-, or -NR. 7 -or-CO-NR 7 - the basis (where R) 7 (e.g., hydrogen atoms or monovalent organic groups with 1-20 carbon atoms). As R 7 The monovalent organic groups representing carbons 1 to 20 can include, for example, monovalent substituted or unsubstituted hydrocarbon groups having carbons 1 to 10, wherein the carbon-carbon bonds in the hydrocarbon group contain -O-, -S-, -CO-, -COO-, or -NR. 7 -or-CO-NR 7 - base etc. In R 5 Or R 6 When the monovalent organic group represented has a substituent, examples of such substituents include: halogen atoms (fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, etc.), hydroxyl groups, thiol groups, amino groups, carboxyl groups, etc.

[0065] R 5 and R 6 Combine with R 5 and R 6The nitrogen-containing heterocyclic structure formed by the bonded nitrogen atoms is preferably an aliphatic ring structure, and more preferably a saturated aliphatic ring structure. Specific examples include pyrimidine ring structures, pyridazine ring structures, and morpholine ring structures. The heterocycle constituting the nitrogen-containing heterocyclic structure may also have substituents. Examples of such substituents include alkyl groups with 1 to 3 carbon atoms, alkoxy groups with 1 to 3 carbon atoms, hydroxyl groups, thiols, carboxyl groups, and amino groups.

[0066] In terms of forming a hardened film with a high tensile elastic modulus and superior adhesion to the substrate, R 5 and R 6 Preferably, they are alkyl groups, or are compounds with R. 5 and R 6 The nitrogen-containing heterocyclic structure formed by the bonded nitrogen atoms, or R 5 and R 6 At least one of them has a secondary amino group or a tertiary amino group.

[0067] Specific examples of N-substituted (meth)acrylamides include N-1 substituted (meth)acrylamides in which one of the two hydrogen atoms bonded to the nitrogen atom of (meth)acrylamide is substituted, N,N-2 substituted (meth)acrylamides in which the two hydrogen atoms bonded to the nitrogen atom of (meth)acrylamide are substituted, and (meth)acrylamides having a nitrogen-containing heterocyclic structure.

[0068] Specific examples of these, as N-1 substituted (meth)acrylamides, include: N-methyl (meth)acrylamides, N-ethyl (meth)acrylamides, N-propyl (meth)acrylamides, N-n-butyl (meth)acrylamides, N-hexyl (meth)acrylamides, N-n-octyl (meth)acrylamides, N-tert-octyl (meth)acrylamides, N-lauryl (meth)acrylamides, N-stearyl (meth)acrylamides, N-oleyl (meth)acrylamides, and other N-alkyl (meth)acrylamides.

[0069] N-methoxymethyl (meth)acrylamide, N-methoxyethyl (meth)acrylamide, N-ethoxymethyl (meth)acrylamide, N-propoxymethyl (meth)acrylamide, N-n-butoxymethyl (meth)acrylamide and N-isobutoxymethyl (meth)acrylamide and other N-alkoxyalkyl (meth)acrylamides;

[0070] N-hydroxyethyl (methyl)acrylamide and other N-hydroxyalkyl (methyl)acrylamides, etc.

[0071] Examples of N,N-2-substituted (meth)acrylamides include: N,N-dimethyl (meth)acrylamides, N,N-diethyl (meth)acrylamides, N,N-methylethyl (meth)acrylamides, N,N-dipropyl (meth)acrylamides, N,N-diisopropyl (meth)acrylamides, N,N-dibutyl (meth)acrylamides, N,N-diisobutyl (meth)acrylamides, N,N-dipentyl (meth)acrylamides, N,N-dihexyl (meth)acrylamides, N,N-diheptyl (meth)acrylamides, N,N-dioctyl (meth)acrylamides, and other N,N-dialkyl (meth)acrylamides.

[0072] N-methoxymethyl-N-methyl (meth)acrylamide, N-methoxyethyl-N-methyl (meth)acrylamide, N-n-butoxymethyl-N-methyl (meth)acrylamide, and other N-alkoxyalkyl-N-alkyl (meth)acrylamides;

[0073] N,N-Dimethylaminopropyl (meth)acrylamide, N,N-Diethylaminopropyl (meth)acrylamide, N,N-Dipropylaminopropyl (meth)acrylamide, N,N-Dimethylaminoethyl (meth)acrylamide, N,N-Diethylaminoethyl (meth)acrylamide, N,N-Dibutylaminopropyl (meth)acrylamide, and other N,N-dialkylaminoalkyl (meth)acrylamides.

[0074] Examples of (meth)acrylamides with nitrogen-containing heterocyclic structures include: (meth)acryloylmorpholine, (meth)acryloylthiomorpholine, N-(meth)acryloyl-4-methylpiperidine, N-(meth)acryloylpiperidine, N-(meth)acryloyl-3,5-dimethylpiperidine, and N-(meth)acryloylpyrrolidine.

[0075] Regarding high curability, N-substituted (meth)acrylamide is preferably at least one selected from the group consisting of N,N-dialkyl (meth)acrylamide, N-alkoxyalkyl (meth)acrylamide, N-hydroxyalkyl (meth)acrylamide, N,N-dialkylaminoalkyl (meth)acrylamide, and (meth)acrylamides having a nitrogen-containing heterocyclic structure, more preferably at least one selected from the group consisting of N,N-dimethyl (meth)acrylamide, N,N-diethyl (meth)acrylamide, (meth)acryloylmorpholine, N-n-butoxymethyl (meth)acrylamide, N-hydroxyethyl (meth)acrylamide, and N,N-dimethylaminopropyl (meth)acrylamide. In addition, regarding the ability to form a hardened film with a higher tensile elastic modulus and better adhesion to the substrate, it is preferable that at least one of the group consisting of N,N-dimethyl (meth)acrylamide, N,N-diethyl (meth)acrylamide, (meth)acryloylmorpholine and N,N-dimethylaminopropyl (meth)acrylamide is selected.

[0076] Relative to 100 parts by mass of the polymerizable compounds contained in this composition, the content of N-substituted (meth)acrylamide in this composition is preferably 20 parts by mass or more, more preferably 30 parts by mass or more, further preferably 40 parts by mass or more, and even more preferably 45 parts by mass or more. By setting the content of N-substituted (meth)acrylamide within the aforementioned range, a hardened film with a sufficiently high tensile modulus and superior adhesion to the substrate (especially the polyimide substrate) can be obtained. Furthermore, from the viewpoint of suppressing the reduction of the elongation at break of the hardened film, the content of N-substituted (meth)acrylamide is preferably 80 parts by mass or less, more preferably 75 parts by mass or less, further preferably 70 parts by mass or less, and even more preferably 68 parts by mass or less, relative to 100 parts by mass of the polymerizable compounds contained in this composition.

[0077] <Component (B): The compound represented by formula (1)>

[0078] The compound represented by formula (1) (hereinafter also referred to as "compound (B)") is a difunctional polymeric compound. From the viewpoint of ensuring the curability of the photocurable composition, it is preferable to increase the content of the monofunctional compound and increase the concentration of the polymeric group in the photocurable composition. On the other hand, if the concentration of the polymeric group in the photocurable composition is increased, the elongation at break of the cured film obtained using the composition is insufficient, and the adhesion to the substrate is also reduced. Therefore, when this type of cured film is applied to a microcoating, in order to place the drive unit on the back side of the display unit, when bending between the display unit and the drive unit to form a bending area, there is a concern that the microcoating may peel off or break from the substrate. In this respect, this composition, by comprising a monofunctional N-substituted (meth)acrylamide and a difunctional compound (B) having a repeating number of alkylene units of 2 or more, can form a cured film with excellent tensile elastic modulus, elongation at break, and adhesion to the substrate while ensuring the curability of the photocurable composition. Furthermore, compound (B) can suppress the increase in viscosity of this composition.

[0079] In the above equation (1), R 3 The alkyl dienoyl group representing 2 to 6 carbon atoms can be either straight-chain or branched. As R 3 Specific examples include: ethylene, 1,3-propanediyl, 1,2-propanediyl, 2,2-propanediyl, 1,4-butanediyl, 1,3-butanediyl, 1,2-butanediyl, 1,5-pentanediyl, 1,4-pentanediyl, 1,6-hexanediyl, 1,5-hexanediyl, etc. From the perspective of obtaining a hardened film with better elongation at break and ease of acquisition, R... 3 Preferably, these are alkyldiyl groups with 2 or 3 carbon atoms.

[0080] In terms of improving the elongation at break of the hardened film obtained using this composition, n in formula (1) is preferably 3 or more, more preferably 4 or more, more preferably 5 or more, and even more preferably 7 or more. Furthermore, from the viewpoint of the ease of obtaining compound (B), n is preferably 14 or less.

[0081] Specific examples of compound (B) include: diethylene glycol di(meth)acrylate (n=2 in formula (1)), triethylene glycol di(meth)acrylate (n=3), polyethylene glycol #200 di(meth)acrylate (n≒4), polyethylene glycol #400 di(meth)acrylate (n≒9), polyethylene glycol #600 di(meth)acrylate (n≒14), dipropylene glycol di(meth)acrylate (n=2), tripropylene glycol di(meth)acrylate (n=3), polypropylene glycol #400 di(meth)acrylate (n≒7), polypropylene glycol #700 di(meth)acrylate (n≒12), etc.

[0082] From the viewpoint of ensuring the elongation at break and reliability of the hardened film obtained using this composition, the content of compound (B) in this composition is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and even more preferably 15 parts by mass or more, relative to 100 parts by mass of the total amount of polymeric compounds contained in this composition. Furthermore, from the viewpoint of ensuring the tensile elastic modulus and adhesion to the substrate of the hardened film, the content of compound (B) is preferably 60 parts by mass or less, more preferably 50 parts by mass or less, and even more preferably 40 parts by mass or less, relative to 100 parts by mass of the total amount of polymeric compounds contained in this composition.

[0083] Furthermore, from the viewpoint of achieving a superior elongation at break of the hardened film, this composition preferably contains a compound in which n is 4 or more in the formula (1). From the viewpoint of fully achieving an improved elongation at break while maintaining a high degree of tensile elastic modulus and adhesion of the hardened film obtained using this composition, the content of the compound in which n is 4 or more in the formula (1) is preferably 2 parts by mass or more, more preferably 5 parts by mass or more, and even more preferably 10 parts by mass or more, further preferably 15 parts by mass or more, and even more preferably 20 parts by mass or more, relative to 100 parts by mass of the polymeric compounds contained in this composition. Furthermore, from the viewpoint of ensuring a high tensile elastic modulus and good adhesion of the hardened film, the content of the compound in which n is 4 or more in the formula (1) is preferably 60 parts by mass or less, more preferably 50 parts by mass or less, and even more preferably 40 parts by mass or less, relative to 100 parts by mass of the polymeric compounds contained in this composition.

[0084] Relative to the total amount of 100 parts by mass of the polymerizable compounds contained in the composition, the total amount of N-substituted (meth)acrylamide and compound (B) in the composition is preferably 25 parts by mass or more, more preferably 50 parts by mass or more, more preferably 65 parts by mass or more, even more preferably 75 parts by mass or more, and even more preferably 80 parts by mass or more.

[0085] <Component (C): Free radical polymerization initiator>

[0086] The preferred free radical polymerization initiator is a photoradioactive initiator that can sense radiation to generate free radicals and initiate polymerization. Examples of radiation include: visible light, ultraviolet light, far ultraviolet light, extreme ultraviolet light, X-rays, gamma rays, and other electromagnetic waves; electron beams, alpha rays, and other charged particle beams. There are no particular limitations on the free radical polymerization initiator contained in this composition; examples include: O-acyl oxime compounds, acetophenone compounds, biimidazole compounds, and acylphosphine oxide compounds.

[0087] Examples of O-acyl oxime compounds include: 1,2-octanedione 1-[4-(phenylthio)-2-(O-benzoyl oxime)], ethyl ketone-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-1-(O-acetyl oxime), 1-(9-ethyl-6-benzoyl-9H-carbazole-3-yl)-octane-1-ketooxime-O-acetate, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-ethane-1-ketooxime-O-benzoate, 1-[9-n-butyl-6-(2-ethylbenzoyl)-9H-carbazole-3-yl]-ethane-1-ketooxime-O-benzoate, ethyl ketone- 1-[9-ethyl-6-(2-methyl-4-tetrahydrofuranylbenzoyl)-9H-carbazole-3-yl]-1-(O-acetyl oxime), acetone-1-[9-ethyl-6-(2-methyl-4-tetrahydropyranylbenzoyl)-9H-carbazole-3-yl]-1-(O-acetyl oxime), acetone-1-[9-ethyl-6-(2-methyl-5-tetrahydrofuranylbenzoyl)-9H-carbazole-3-yl]-1-(O-acetyl oxime), acetone-1-[9-ethyl-6-{2-methyl-4-(2,2-dimethyl-1,3-dioxane-1,3-dioxane-pentyl)methoxybenzoyl}-9H-carbazole-3-yl]-1-(O-acetyl oxime), etc. O-acyl oxime compounds may preferably use polymerization initiators having a carbazole skeleton in the molecule (e.g., acetone-1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-1-(O-acetyl oxime), etc.).

[0088] Examples of acetophenone compounds include, for example, α-aminoketone compounds and α-hydroxyketone compounds. Specific examples of these include, for α-aminoketone compounds, 2-benzyl-2-dimethylamino-1-(4-morpholinylphenyl)-butane-1-one, 2-dimethylamino-2-(4-methylbenzyl)-1-(4-morpholin-4-yl-phenyl)-butane-1-one, and 2-methyl-1-(4-methylthiophenyl)-2-morpholinylpropane-1-one. Examples of α-hydroxyketone compounds include 1-phenyl-2-hydroxy-2-methylpropane-1-one, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropane-1-one, 4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl)one, and 1-hydroxycyclohexylphenyl ketone.

[0089] Examples of biimidazole compounds include 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole, 2,2'-bis(2,4-dichlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole, or 2,2'-bis(2,4,6-trichlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole, etc.

[0090] Examples of acylphosphine oxide compounds include 2,4,6-trimethylbenzoyl-diphenylphosphine oxide and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide.

[0091] From the viewpoint of ensuring good curability, the content of the free radical polymerization initiator in this composition is preferably 0.2 parts by mass or more, more preferably 0.5 parts by mass or more, and even more preferably 1 part by mass or more, relative to 100 parts by mass of the polymerizable compounds contained in this composition. Furthermore, the content of the free radical polymerization initiator is preferably 15 parts by mass or less, more preferably 10 parts by mass or less, even more preferably 5 parts by mass or less, and even more preferably 2 parts by mass or less, relative to 100 parts by mass of the polymerizable compounds contained in this composition. By setting the content of the free radical polymerization initiator to 15 parts by mass or less, good curability can be achieved while suppressing the generation of gases from decomposition products. Additionally, by having the free radical polymerization initiator act as a plasticizer, the decrease in the tensile elastic modulus of the cured film can be suppressed.

[0092] <Other Ingredients>

[0093] In addition to the N-substituted (meth)acrylamide, compound (B), and free radical polymerization initiator described above, this composition may also contain components different from the N-substituted (meth)acrylamide, compound (B), and free radical polymerization initiator (hereinafter also referred to as "other components"). Examples of other components include: compounds different from N-substituted (meth)acrylamide as monofunctional polymerizable compounds (hereinafter also referred to as "monofunctional compound (D1)"), compounds different from compound (B) as polyfunctional polymerizable compounds (hereinafter also referred to as "polyfunctional compound (D2)"), surfactants, etc.

[0094] • Monofunctional compounds (D1)

[0095] The monofunctional compound (D1) is a component capable of copolymerizing with N-substituted (meth)acrylamide and compound (B), and is a compound that can form polymers with N-substituted (meth)acrylamide and compound (B) upon exposure to radiation. The monofunctional compound (D1) can be formulated into the composition for various purposes, such as adjusting the viscosity of the composition, enhancing the crosslinking structure, adjusting the elongation at break of the hardened film, or improving its adhesion to the substrate.

[0096] As a monofunctional compound (D1), a compound having an vinyl unsaturated group as a polymerizable group is preferably used. Specifically, examples include: vinyl compounds, compounds containing (meth)acryloyl groups, aromatic vinyl compounds, etc. Among these, (meth)acrylate compounds are preferably used in terms of copolymerization with N-substituted (meth)acrylamide and compound (B), or in terms of the ease with which the viscosity of the composition can be adjusted.

[0097] Specific examples of monofunctional compounds (D1) include: alkyl methacrylates, methacrylates having an alicyclic structure, methacrylates having an aromatic ring structure, alkoxyalkyl methacrylates, methacrylate compounds having an amino group, methacrylate compounds having a hydroxyl group, methacrylate compounds having a phosphate group, methacrylate compounds having a carbamate group, aromatic vinyl compounds, etc.

[0098] Specific examples of the compounds mentioned above, as alkyl methacrylates, include: methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, n-decyl methacrylate, n-undecyl methacrylate, n-lauryl methacrylate, n-tridecyl methacrylate, n-tetradecyl methacrylate, n-pentadecanyl methacrylate, n-hexadecyl methacrylate, n-stearyl methacrylate, isostearyl methacrylate, n-nonadecanyl methacrylate, n-eicosyl methacrylate, etc.

[0099] Examples of (meth)acrylates with an alicyclic structure include: cyclohexyl (meth)acrylate, 2-methylcyclohexyl (meth)acrylate, and tricyclic (meth)acrylate [5.2.1.0]. 2,6 ] Decane-8-yl ester, (meth)acrylate tricyclic [5.2.1.0] 2,5 Examples of methacrylates with aromatic ring structures include: phenyl methacrylate, benzyl methacrylate, naphthyl methyl methacrylate, naphthyl ethyl methacrylate, phenoxy ethyl methacrylate, m-phenoxyphenyl methyl methacrylate, and o-phenylphenoxyethyl methacrylate.

[0100] Examples of alkoxyalkyl esters of (meth)acrylate include: 2-methoxyethyl ester, 2-ethoxyethyl ester, n-propoxyethyl ester, n-butoxyethyl ester, 3-methoxypropyl ester, 3-ethoxypropyl ester, n-propoxypropyl ester, n-butoxypropyl ester, methoxybutyl ester, ethoxybutyl ester, n-propoxybutyl ester, and n-butoxybutyl ester.

[0101] Examples of (meth)acrylate compounds containing an amino group include: dimethylaminomethyl (meth)acrylate, diethylaminomethyl (meth)acrylate, 2-dimethylaminoethyl (meth)acrylate, 2-diethylaminoethyl (meth)acrylate, 2-(di-n-propylamino)ethyl (meth)acrylate, 2-dimethylaminopropyl (meth)acrylate, 2-diethylaminopropyl (meth)acrylate, 2-(di-n-propylamino)propyl (meth)acrylate, 3-dimethylaminopropyl (meth)acrylate, 3-diethylaminopropyl (meth)acrylate, and 3-(di-n-propylamino)propyl (meth)acrylate.

[0102] Examples of (meth)acrylate compounds having hydroxyl groups include: 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate.

[0103] As a (meth)acrylate compound having a phosphoric acid group, it can be a compound formed by substituting one or more of the three hydroxyl groups in phosphoric acid (O=P(OH)3) with an organic group having a (meth)acryloyloxy group. Specific examples of (meth)acrylate compounds with phosphate groups include: the Phosmer series (Phosmer-M, Phosmer-CL, Phosmer-PE, Phosmer-MH, Phosmer-PP) manufactured by Uni-chemical Co., Ltd.; the KAYAMER series (e.g., KAYAMER PM-21, KAYAMER PM-2) manufactured by Nippon Kayaku Co., Ltd.; PPME, PMR12, PPM-5P manufactured by Toho Chemical Co., Ltd.; and the Light Ester series (e.g., Light Ester P-2M) manufactured by Kyoeisha Chemical Co., Ltd., etc.

[0104] Examples of urethane (meth)acrylate compounds having a urethane group include: methylaminocarbonyloxyethylidene (meth)acrylate, ethylaminocarbonyloxyethylidene (meth)acrylate, propylaminocarbonyloxyethylidene (meth)acrylate, butylaminocarbonyloxyethylidene (meth)acrylate, pentylaminocarbonyloxyethylidene (meth)acrylate, and hexylaminocarbonyloxyethylidene (meth)acrylate, etc.

[0105] Examples of aromatic vinyl compounds include styrene, methylstyrene, α-methylstyrene, tert-butoxystyrene, and vinylnaphthalene.

[0106] When a monofunctional compound (D1) is incorporated into this composition, from the viewpoint of ensuring the adhesion of the hardened film obtained from this composition to the substrate and maintaining a high tensile elastic modulus and elongation at break, the content of the monofunctional compound (D1) is preferably 70 parts by mass or less, more preferably 60 parts by mass or less, more preferably 40 parts by mass or less, and even more preferably 20 parts by mass or less, relative to 100 parts by mass of the total amount of polymerizable compounds contained in this composition (i.e., the total amount of N-substituted (meth)acrylamide, compound (B), monofunctional compound (D1) and polyfunctional compound (D2).

[0107] As a monofunctional compound (D1), it is preferable to use at least one of the group consisting of alkyl methacrylates and methacrylate compounds having phosphate groups, in order to obtain the effect of improving the elongation at break or adhesion of the hardened film obtained by the composition.

[0108] When this composition also contains alkyl (meth)acrylate, the elongation at break of the hardened film obtained from this composition can be further improved. From the viewpoint of improving the effect of increasing the elongation at break of the hardened film, the alkyl (meth)acrylate formulated into this composition is preferably an alkyl group having 6 or more carbon atoms, and more preferably an alkyl group having 10 or more carbon atoms.

[0109] When alkyl (meth)acrylate is incorporated into this composition, from the viewpoint of sufficiently obtaining the improved elongation at break of the hardened film obtained by this composition, the content of alkyl (meth)acrylate is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, relative to 100 parts by mass of the total amount of polymerizable compounds contained in this composition. Furthermore, from the viewpoint of ensuring the adhesion and tensile elastic modulus of the hardened film, the content of alkyl (meth)acrylate is preferably 70 parts by mass or less, more preferably 60 parts by mass or less, and even more preferably 40 parts by mass or less, relative to 100 parts by mass of the total amount of polymerizable compounds contained in this composition.

[0110] From the viewpoint of further improving the adhesion of the hardened film obtained from this composition to the substrate, this composition preferably also contains a (meth)acrylate compound having a phosphate group. When a (meth)acrylate compound having a phosphate group is incorporated into this composition, the content of the (meth)acrylate compound having a phosphate group is preferably 1 part by mass or more, more preferably 1.5 parts by mass or more, and even more preferably 2 parts by mass or more, relative to 100 parts by mass of the polymerizable compounds contained in this composition. Furthermore, from the viewpoint of moderately reducing the viscosity of this composition and increasing the tensile elastic modulus of the hardened film obtained using this composition, the content of the (meth)acrylate compound having a phosphate group is preferably 20 parts by mass or less, more preferably 10 parts by mass or less, and even more preferably 5 parts by mass or less, relative to 100 parts by mass of the polymerizable compounds contained in this composition.

[0111] On the other hand, when a urethane-based (meth)acrylate compound is incorporated into this composition, the hardened film (microcoating) is prone to deterioration under high temperature and humidity, which can easily lead to a decrease in the reliability of the display device. In particular, since the microcoating is sometimes disposed on the outermost layer of the display panel, it may be exposed to the atmosphere, thus requiring performance to be maintained under more stringent conditions. From this perspective, the content of the urethane-based (meth)acrylate compound in this composition is preferably as low as possible. Specifically, relative to 100 parts by mass of the total amount of polymerizable compounds contained in this composition, the content of the urethane-based (meth)acrylate compound is preferably 3 parts by mass or less, more preferably 1.5 parts by mass or less, further preferably 1 part by mass or less, and even more preferably 0.5 parts by mass or less. Furthermore, this composition is particularly preferably free of urethane-based (meth)acrylate compounds.

[0112] Relative to the total amount of 100 parts by mass of polymerizable compounds contained in the composition, the total amount of N-substituted (meth)acrylamide, compound (B), alkyl (meth)acrylate and (meth)acrylate compound having a phosphate group in the composition is preferably 75 parts by mass or more, more preferably 80 parts by mass or more, even more preferably 85 parts by mass or more, and even more preferably 90 parts by mass or more.

[0113] • Multifunctional compound (D2)

[0114] Like the monofunctional compound (D1), the multifunctional compound (D2) is a component capable of copolymerizing with N-substituted (meth)acrylamide and compound (B). Upon exposure to radiation, it can form polymers with N-substituted (meth)acrylamide and compound (B). The multifunctional compound (D2) can be formulated into the composition for purposes such as adjusting the viscosity or enhancing the cross-linking structure.

[0115] As the multifunctional compound (D2), a compound having an ethylene unsaturated group as a polymerizable group is preferably used. In terms of copolymerization with N-substituted (meth)acrylamide and compound (B), or in terms of the ease with which the viscosity of this composition can be adjusted, a (meth)acrylate compound is preferably used as the multifunctional compound (D2).

[0116] Specific examples of multifunctional compounds (D2) include difunctional (meth)acrylates and trifunctional or higher (meth)acrylates. Specific examples of these, as difunctional (meth)acrylates, include neopentyl glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, and 1,10-decanediol di(meth)acrylate.

[0117] Examples of trifunctional or higher (meth)acrylates include, in addition to, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, ethylene oxide modified dipentaerythritol hexa(meth)acrylate, tris(2-(meth)acryloyloxyethyl)phosphate, succinic acid modified pentaerythritol tri(meth)acrylate, succinic acid modified dipentaerythritol penta(meth)acrylate, and carboxyl-containing polyacid-modified (meth)acrylate oligomers, compounds having straight-chain alkylene and alicyclic structures and having two or more isocyanate groups, and compounds having one or more hydroxyl groups and having three, four, or five (meth)acryloyloxy groups, which are obtained by reacting them to form polyfunctional carbamate acrylate compounds.

[0118] From the viewpoint of ensuring the curability of this composition, and from the viewpoint of suppressing the reduction of the elongation at break of the cured film and the adhesion to the substrate, the content of the polyfunctional compound (D2) is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and even more preferably 2 parts by mass or less, relative to 100 parts by mass of the total amount of polymerizable compounds contained in this composition.

[0119] Surfactants

[0120] Surfactants can be used to further improve the coatability of this composition (specifically, wetting spread or reduction of coating unevenness). Examples of surfactants include, for example, fluorinated surfactants (including fluorinated nonionic surfactants), silicone surfactants, and nonionic surfactants.

[0121] Specific examples of surfactants, as fluorinated surfactants, include the following trade names: Megafac F-171, Megafac F-172, Megafac F-173, Megafac F-251, Megafac F-430, Megafac F-554, Megafac F-563 (manufactured by DIC); Fluorad FC430, Fluorad FC431 (manufactured by Sumitomo 3M); Asahi... Guard AG710, Surflon S-382, Surflon SC-101, Surflon SC-102, Surflon SC-103, Surflon SC-104, Surflon SC-105, Surflon SC-106, Surflon S-611 (manufactured by AGC SEIMIChemical); Polyflow No.75, Polyflow No.95 (manufactured by Kyoei Chemicals); FTX-218 (manufactured by NEOS); Eftop EF301, Eftop EF303, Eftop EF352 (manufactured by Shin-Akita Chemicals), etc.

[0122] As silicone-based surfactants, the following trade names can be listed: SH200-100cs, SH28PA, SH30PA, SH89PA, SH190, SH8400, SH193, SZ6032, SF8428, DC57, DC190, PAINTAD 19, FZ-2101, FZ-77, FZ-2118, L-7001, L-7002 (Toray Dow Corning). (manufactured by Corning Corporation); organosiloxane polymer KP341 (manufactured by Shin-Etsu Chemical Industry Co., Ltd.); BYK-300, BYK-306, BYK-310, BYK-330, BYK-333, BYK-335, BYK-341, BYK-344, BYK-370, BYK-340, BYK-345 (manufactured by BYK-Chemie Japan Co., Ltd.).

[0123] Examples of nonionic surfactants include: polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oil-based ether, polyoxyethylene n-octylphenyl ether, polyoxyethylene n-nonylphenyl ether, polyethylene glycol dilaurate, and polyethylene glycol distearate.

[0124] When a surfactant is incorporated into this composition, the surfactant content is preferably 0.01 to 3 parts by mass, more preferably 0.02 to 2 parts by mass, and even more preferably 0.1 to 1.0 parts by mass, relative to 100 parts by mass of the polymerizable compound contained in the composition.

[0125] Other components, besides those listed, may include, for example, polymerization inhibitors, antioxidants, sensitizers, softeners, plasticizers, adhesion promoters, and organic solvents. The proportions of these components can be appropriately selected based on their suitability without impairing the effects of this disclosure.

[0126] Organic solvents may be incorporated into this composition for the purpose of dissolving and preparing the various components. On the other hand, from the viewpoint of forming a hardened film (i.e., a microcoating) without heat treatment, it is preferable to minimize the amount of organic solvent used. Specifically, the content of organic solvent in this composition is preferably 0% by mass or more and 3% by mass or less, more preferably 0% by mass or more and 2% by mass or less, and particularly preferably substantially non-existent. Here, in this specification, "substantially non-existent" means that the amount of organic solvent contained in this composition is 1% by mass or less, preferably 0.5% by mass or less.

[0127] When an organic solvent is incorporated into this composition, it is preferable to use an organic solvent that can dissolve or disperse the components incorporated into the composition and does not react with the components. Specifically, examples include: alcohols, ketones, esters, ethers, aromatic hydrocarbons, and amides.

[0128] Specific examples of these include, as alcohols: methanol, ethanol, isopropanol, butanol, octanol, etc.; as ketones: acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc.; as esters: ethyl acetate, butyl acetate, ethyl lactate, γ-butyrolactone, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, methyl-3-methoxypropionate, etc.; as ethers: polyoxyethylene lauryl ether, ethylene glycol monomethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, diethylene glycol methyl ethyl ether, etc.; as aromatic hydrocarbons: benzene, toluene, xylene, etc.; and as amides: dimethylformamide, dimethylacetamide, N-methylpyrrolidone, etc.

[0129] <Preparation of Photocurable Compositions>

[0130] This composition can be prepared by mixing N-substituted (meth)acrylamide, compound (B), a free radical polymerization initiator, and other components as needed. From the viewpoint of producing a photocurable composition with good sensitivity to radiation, or from the viewpoint of forming a curing film with excellent reliability, the content of the polymerizable compound in this composition (i.e., the total amount of N-substituted (meth)acrylamide, compound (B), monofunctional compound (D1), and polyfunctional compound (D2)) is preferably 80 parts by mass or more, more preferably 85 parts by mass or more, and even more preferably 90 parts by mass or more, relative to 100 parts by mass of the total composition.

[0131] <Viscosity>

[0132] The viscosity of this composition, measured using an E-type viscometer at 25°C and 20 rpm, is preferably in the range of 1.0 mPa·s to 35.0 mPa·s. If the viscosity of this composition is 35.0 mPa·s or less, it exhibits good wetting and spreading properties when applied to a substrate by inkjet coating, suppressing uneven coating caused by pitting or other defects. Conversely, if the viscosity of this composition is 1.0 mPa·s or more, sufficient film thickness can be ensured when applying it to a substrate. This composition is preferably a curing composition for inkjet coating.

[0133] From the viewpoint of obtaining a photocurable composition with excellent inkjet coating properties, the viscosity of this composition is more preferably 30.0 mPa·s or less, more preferably 25.0 mPa·s or less, and even more preferably 22.0 mPa·s or less. Furthermore, from the viewpoint of stably performing inkjet-based ejection and sufficiently ensuring film thickness, the viscosity of this composition is more preferably 2.0 mPa·s or more, more preferably 5.0 mPa·s or more, and even more preferably 10.0 mPa·s or more. In addition, in this specification, the viscosity of the photocurable composition is a value measured according to Japanese Industrial Standard (JIS) K2283.

[0134] <Tension modulus>

[0135] By curing this composition, a hardened film with a sufficiently high tensile elastic modulus can be obtained. Specifically, for films cured under an illuminance of 1000 mW / cm², 2 And the cumulative light intensity is 1000 mJ / cm 2A 50 μm thick hardened film obtained by irradiating the composition with ultraviolet light at a wavelength of 395 nm under the specified conditions, preferably has a tensile elastic modulus of 0.8 GPa or higher as measured by the tensile test method based on JIS K6911 at 23°C. From the viewpoint of obtaining a micro-coating with excellent bending resistance, the tensile elastic modulus of the hardened film measured under the aforementioned conditions is more preferably 0.9 GPa or higher, and even more preferably 1.0 GPa or higher. Furthermore, the tensile elastic modulus of the hardened film measured under the aforementioned conditions is preferably 2.5 GPa or lower, and more preferably 2.0 GPa or lower. Regarding the details of the measurement method for the tensile elastic modulus of the hardened film, the method described in the examples below is followed.

[0136] <Elongation at break>

[0137] Furthermore, by curing this composition, a hardened film with sufficiently high elongation at break can be obtained. Specifically, for films cured under an illuminance of 1000 mW / cm², 2 And the cumulative light intensity is 1000 mJ / cm 2 A 50 μm thick hardened film obtained by irradiating the composition with ultraviolet light at a wavelength of 395 nm under the specified conditions preferably has an elongation at break of 20% or more, measured at 23°C according to the tensile test method based on JIS K6911. From the viewpoint of obtaining a micro-coating with excellent bending resistance, the elongation at break of the hardened film measured under the aforementioned conditions is more preferably 30% or more, more preferably 40% or more, and even more preferably 50% or more. Furthermore, from the viewpoint of ensuring device reliability, the elongation at break of the hardened film measured under the aforementioned conditions is preferably 180% or less, more preferably 150% or less. Moreover, regarding the details of the measurement method for the elongation at break of the hardened film, the method described in the examples described later is followed.

[0138] Microcoatings and Display Devices

[0139] The microcoating disclosed herein is formed from a photocurable composition prepared as described. This composition provides a cured film with excellent bending resistance and adhesion to substrates (particularly resin substrates). This composition is preferably used as a material for forming a microcoating to protect the wiring from external influences in the curved areas where wiring extends from the display portion to the drive portion is provided, particularly in the region connecting the display portion of a display device to the drive portion on the back side of the display portion.

[0140] Suitable for use Figures 1-3 This describes an embodiment that realizes a display device comprising a micro-coating formed from the present composition as an organic EL display device. Furthermore, Figure 1 The image shows a display device with the drive unit positioned on the rear side of the display unit. Figure 2The image shows a display device with the drive unit positioned on the rear side of the display unit. Figure 3 It includes Figure 2 An enlarged cross-sectional view of the curved region SD in the image.

[0141] like Figure 1 and Figure 2 As shown, the display device 10 includes a display unit 12 having a pixel array layer 11 and a driving unit 13 for driving the pixel array layer 11. The pixel array layer 11 is an organic EL layer on a substrate 14, on which thin-film transistors or electrode layers, planarization layers, transport layers, barrier layers, organic light-emitting layers, sealing layers, etc. are stacked. Since the pixel array layer 11 is a known organic EL layer, detailed description is omitted here.

[0142] The substrate 14 is a flexible transparent resin film. Examples of resins used to form the substrate 14 include polyester, polyolefin, polystyrene, polyimide, polyamide, polyamide-imide, polyetherimide, polyarylate, polyethersulfone, polysulfone, polyetheretherketone, polycarbonate, polyvinyl chloride, polyvinylidene chloride, and polyurethane. Alternatively, the substrate 14 may also be a glass substrate. In the display section 12, in addition to the pixel array layer 11, optical films or polarizing plates, cover glass, etc., are also stacked.

[0143] The driving unit 13 includes a driver integrated circuit (IC) 16 disposed on the substrate 15, which controls the driving of the pixel array layer 11. The substrate 15 may be a flexible transparent resin film, and the driving unit 13 may have an on-chip film structure. The driving unit 13 is connected to the pixel array layer 11 via wiring 17. The driving unit 13 outputs signals to the pixel array layer 11 based on signals received from the circuit board 18, thereby displaying an image on the display unit 12.

[0144] The driving unit 13 is disposed separately from the display unit 12 in a non-display area SB on the substrate 14. Within the non-display area SB, a wiring area SC is provided in the region between the display unit 12 and the driving unit 13, where wiring 17 is disposed. Before the driving unit 13 is disposed on the back side of the display unit 12, the display unit 12 and the driving unit 13 are arranged horizontally in a state separated by the wiring area SC (see reference). Figure 1 In the wiring region SC, a microcoating 19 is formed to cover the wiring 17. The microcoating 19 is formed by curing the composition. The microcoating 19 is disposed on the outermost layer of the wiring region SC in a manner that covers the entire wiring 17, and has a specified thickness (e.g., 10 μm to 150 μm).

[0145] In order to obtain Figure 2The display device 10 shown is configured such that the driving unit 13 is positioned on the rear side relative to the display unit 12, in the wiring area SC portion ( Figure 1 The substrate 14 is folded back by the folding line LA in the diagram. This forms a curved region SD (see reference LA) in the display device 10. Figure 2 ).like Figure 3 As shown, a wiring 17 and a micro-coating 19 covering the surface of the wiring 17 are disposed in the curved region SD. With the curved region SD formed, the rear side surface 12a of the display unit 12 and the rear side surface 13a of the drive unit 13 face each other. That is, in the display device 10, the display unit 12 is disposed on the front side (viewer side) of the display device 10, and the drive unit 13 is disposed on the rear side. This allows for a narrow bezel in the display device 10.

[0146] <Manufacturing Method of Display Device>

[0147] Next, a method for manufacturing the display device of this disclosure will be described. The display device of this disclosure can be manufactured by a method comprising the following steps 1 to 4.

[0148] Process 1: The process of separating the display unit from the drive unit and arranging them horizontally.

[0149] Step 2: The step of coating the composition onto a substrate containing the area between the display section and the driving section.

[0150] Step 3: A step of obtaining a micro-coating by irradiating the composition on a substrate with radiation to harden it.

[0151] Process 4: The process of forming a curved area connecting the display unit and the drive unit by bending the area containing the micro-coating.

[0152] In step 1, the method of arranging the display unit and the driving unit separately along the horizontal direction is not particularly limited, and can be performed according to known methods. In step 1, the display unit and the driving unit can be arranged on the same surface of the same substrate. Alternatively, the display unit and the driving unit can be arranged on different substrates, and the first substrate on which the display unit is arranged can be directly or via a third substrate to connect the second substrate on which the driving unit is arranged, thereby arranging the display unit and the driving unit along the horizontal direction.

[0153] In step 2, methods for coating this composition include, for example, spraying, roller coating, spin coating, slot die coating, bar coating, and inkjet coating. In terms of yield and thin-film formation, inkjet coating is preferred. In particular, this composition exhibits excellent curing properties while maintaining low viscosity, suppressing uneven coating and thus making it suitable for inkjet coating.

[0154] In step 3, a hardened film as a micro-coating is obtained by irradiating the coating film formed in step 2 with radiation and then hardening the coating film. Examples of radiation include ultraviolet light, far-ultraviolet light, visible light, X-rays, and charged particle beams such as electron beams. Ultraviolet light is preferred among these, and for example, ultraviolet light with a wavelength of 350 nm to 400 nm can be preferably used as the irradiation light. The exposure dose of the radiation is preferably 100 J / m². 2 ~3,000 J / m 2 From the perspective of adequately protecting the wiring, the thickness of the hardened film is approximately 5 μm to 150 μm.

[0155] In step 4, for a device including a display section and a driving section arranged in a horizontal direction, the area containing the micro-coating (i.e., Figure 1 The wiring area SC in the display unit is folded back, thereby positioning the drive unit on the rear side of the display unit. This folds back the area connecting the display unit and the drive unit to form a curved area SD (see reference). Figure 2 ).

[0156] [Example]

[0157] The present invention will be specifically described below through examples, but the present invention is not limited to the following examples. Furthermore, unless otherwise specified, "parts" and "%" in the examples and comparative examples refer to quality standards.

[0158] 1. Preparation of photocurable compositions

[0159] The following shows the types and abbreviations of N-substituted (meth)acrylamide, compound (B), monofunctional compound (D1), polyfunctional compound (D2), free radical polymerization initiator and surfactant used in the preparation of photocurable compositions.

[0160] <N-substituted (meth)acrylamide>

[0161] A-1: Acryloylmorpholine [Trade name: ACMO, manufactured by KJ Chemical Company]

[0162] A-2: N,N-Diethylacrylamide [Trade name: DEAA, manufactured by KJ Chemical Company]

[0163] <Compound (B)>

[0164] B-1: Polyethylene glycol #200 diacrylate [Trade name: NK ester (NK ester) A-400, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.]

[0165] B-2: Polypropylene glycol #400 diacrylate [Trade name: NK ester (NK ester) APG-400, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.]

[0166] B-3: Polypropylene glycol #700 diacrylate [Trade name: NK ester (NK ester) APG-700, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.]

[0167] <Monofunctional Compound (D1)>

[0168] D1-1: Isostearyl acrylate [Trade name: ISTA, manufactured by Osaka Organic Chemicals Co., Ltd.]

[0169] D1-2: Isobornyl acrylate [Trade name: IBXA, manufactured by Osaka Organic Chemicals Co., Ltd.]

[0170] D1-3: 1-Naphthylmethyl acrylate [Trade name: Light Acrylate 1-NMTA, manufactured by Kyoei Chemical Co., Ltd.]

[0171] D1-4: Phosphoric acid-containing (meth)acrylate compounds [trade name PPM-5P, manufactured by Toho Chemical Co., Ltd.]

[0172] <Multifunctional compound (D2)>

[0173] D2-1: 1,9-Nonanediol diacrylate [Trade name: NK ester (NK ester) A-NOD-N, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.]

[0174] <Free radical polymerization initiators>

[0175] C-1: Omnirad 819 [Trade name: Omnirad 819, manufactured by IGM Resins]

[0176] C-2: TR-PBG-345 [Product Name: TR-PBG-345, manufactured by Changzhou Qiangli Advanced Electronic Materials Co., Ltd.]

[0177] <surfactants>

[0178] E-1: Silicone surfactant [Trade name: BYK-333, manufactured by BYK-Chemie Japan]

[0179] [Example 1]

[0180] 70.0 parts by weight of compound (A-1), 30 parts by weight of compound (B-3), 1 part by weight of free radical polymerization initiator (C-1), and 0.1 parts by weight of surfactant (E-1) were prepared into a glass sample vial and mixed uniformly to obtain a mixture. The mixture was then filtered using a PTFE filter to obtain a photocurable composition (R-1).

[0181] [Examples 2-7, Comparative Examples 1-3]

[0182] Using the types and proportions (parts by mass) of each component shown in Table 1, except that photocurable compositions (R-2) to (R-7) and (CR-1) to (CR-3) of Examples 2 to 7 and Comparative Examples 1 to 3 were prepared using the same method as in Example 1.

[0183] 2. Evaluation

[0184] The viscosity of the photocurable compositions of Examples 1 to 7 and Comparative Examples 1 to 3 was measured. Furthermore, cured films were formed using the photocurable compositions of Examples 1 to 7 and Comparative Examples 1 to 3, and evaluated using the methods described below. The evaluation results are shown in Table 1.

[0185] <Viscosity Measurement>

[0186] The viscosity (mPa·s) of each light-curing composition was measured using an E-type viscosity measuring device (RE-85L manufactured by Toki Sangyo Co., Ltd.) under the following conditions.

[0187] [Measurement Conditions]

[0188] Conical rotor: Standard conical rotor (1°34'×R24)

[0189] Measurement temperature: 25℃

[0190] Measurement range: M

[0191] Speed: 20 rpm

[0192] <Tension modulus, elongation at break>

[0193] Each photocurable composition was applied to alkali-free glass using a spin coater to achieve a cured thickness of 50 μm. Next, each photocurable composition on the alkali-free glass was subjected to UV curing using a light-emitting diode (LED) lamp at an illuminance of 1000 mJ / cm². 2 Cumulative light intensity 1,000 mJ / cm 2The film was irradiated with 395 nm ultraviolet light and then cured. A UniJet E110Z HD (Type U395A-455, manufactured by Ushio Electric Co., Ltd.) LED UV lamp was used. The resulting cured film was cut into strips 6 mm wide and 25 mm long. The tensile modulus of elasticity and the maximum elongation at break (elongation at break) of the cured film at 23°C were determined using a tensile test method based on JIS K6911.

[0194] <Tightness>

[0195] A polyimide film (trade name Kapton (registered trademark), manufactured by Toray DuPont) was attached to a silicon wafer, and various photocurable compositions were coated using a spin coater to achieve a cured thickness of 10 μm. Next, each photocurable composition on the polyimide film was subjected to UV curing using an LED UV lamp at 1,000 mJ / cm². 2 The light source irradiates the lamp with 395 nm ultraviolet light to harden it. As an LED UV lamp, a UniJet E110Z HD (Type U395A-455, manufactured by USHIO Electric Co., Ltd.) was used.

[0196] The obtained hardened film was cross-cut into 1 mm × 1 mm squares (checkerboard pattern), forming 100 areas surrounded by the cuts. Adhesive peel-off tape was applied to each of the 100 areas, and then the tape was peeled off. The adhesion of the hardened film to the polyimide film was evaluated based on the number of areas where the hardened film peeled off from the polyimide film after peeling off the tape. The fewer the number of peeled areas, the better the adhesion of the hardened film to the polyimide film. Table 1 shows the number of peeled areas among the 100 areas formed on the hardened film. The peel-off tape used was Scotch #610, manufactured by 3M: 402 N / 100 mm (longitudinal).

[0197] [Table 1]

[0198]

[0199] As shown in Table 1, the cured films obtained from the photocurable compositions (R-1) to (R-7) of Examples 1 to 7 exhibit high tensile elastic modulus and elongation at break, resulting in excellent adhesion to the substrate. In contrast, the cured film obtained from the photocurable composition (CR-1) of Comparative Example 1, which does not contain compound (B), has insufficient elongation at break. Furthermore, the cured films obtained from the photocurable compositions (CR-2) and (CR-3) of Comparative Examples 2 and 3, which do not contain N-substituted (meth)acrylamide, have low elongation at break and poor adhesion to the substrate.

Claims

1. A photocurable composition for forming a microcoating, wherein the microcoating is disposed in a curved region connecting a display portion having a pixel array layer and a driving portion for driving the pixel array layer, the photocurable composition for forming the microcoating comprising: N-substituted (meth)acrylamide; The compound represented by the following formula (1); and Free radical polymerization initiators CH2=CR 1 -CO-O-(R 3 -O) n -CO-CR 2 =CH2···(1) In equation (1), R 1 and R 2 Each is independently a hydrogen atom or a methyl group; R 3 It is an alkyldiyl group with 2 to 6 carbon atoms; n is an integer from 2 to 15; multiple R in the formula 3 Same or different.

2. The photocurable composition for forming microcoatings according to claim 1, wherein n in formula (1) is 4 or more.

3. The photocurable composition for forming microcoatings according to claim 1 further comprises a (meth)acrylate compound having a phosphate group.

4. The photocurable composition for forming microcoatings according to claim 3, wherein the content of the phosphate-containing (meth)acrylate compound is 1 to 20 parts by mass relative to 100 parts by mass of the total amount of polymerizable compounds in the composition.

5. The photocurable composition for forming microcoatings according to claim 1, wherein the content of N-substituted (meth)acrylamide is 20 to 80 parts by mass relative to 100 parts by mass of the total amount of polymerizable compounds in the composition.

6. The photocurable composition for forming microcoatings according to claim 1, wherein the content of the compound represented by formula (1) is 5 to 60 parts by mass relative to 100 parts by mass of the total amount of polymerizable compound in the composition.

7. The photocurable composition for forming microcoatings according to claim 1, wherein the content of the free radical polymerization initiator is 0.2 to 15 parts by mass relative to 100 parts by mass of the total amount of polymerizable compounds in the composition.

8. The photocurable composition for forming microcoatings according to claim 1, wherein the viscosity measured using an E-type viscometer at 25°C and 20 rpm is 1.0 mPa·s to 35.0 mPa·s.

9. The photocurable composition for forming microcoatings according to claim 1, wherein the curing is achieved at an illuminance of 1000 mW / cm². 2 And the cumulative light intensity is 1000 mJ / cm 2 Under certain conditions, a hardened film with a thickness of 50 μm obtained by irradiating the photocurable composition with ultraviolet light of wavelength 395 nm has a tensile elastic modulus of 0.8 GPa or higher.

10. The photocurable composition for forming microcoatings according to claim 1, wherein the curing is achieved at an illuminance of 1000 mW / cm². 2 And the cumulative light intensity is 1000 mJ / cm 2 Under certain conditions, the elongation at break of a 50 μm thick hardened film obtained by irradiating the photocurable composition with ultraviolet light of wavelength 395 nm is 20% or more.

11. A microcoating formed by curing a photocurable composition for forming a microcoating as described in any one of claims 1 to 10.

12. A display device, comprising: The display section has a pixel array layer; The driving unit drives the pixel array layer; as well as The curved area connects the display unit and the driving unit. The curved region includes a microcoating formed by a photocurable composition for microcoating formation as described in any one of claims 1 to 10.

13. A method for manufacturing a display device, comprising a display section having a pixel array layer and a driving section for driving the pixel array layer, the method comprising: A process of arranging the display unit and the driving unit in a horizontal direction while separating them; A process of coating a substrate containing the region between the display portion and the driving portion with a photocurable composition for forming a microcoating as described in any one of claims 1 to 10; The process of obtaining a microcoating by irradiating the substrate with a photocurable composition and then curing it. as well as The process of forming a curved region connecting the display unit and the drive unit by bending the area containing the micro-coating.

14. The method of manufacturing a display device according to claim 13, wherein the photocurable composition for forming the microcoating is applied by inkjet coating.

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