Curable composition, cured product thereof, LED element, electronic device, and optical element

Abstract

Provided is a curable composition capable of forming a cured product having excellent curability and storage stability, as well as excellent heat resistance, light resistance, moisture resistance, transparency, and adhesion to a substrate by an ink jet method. Provided is a curable composition containing, as essential components, (a) a (meth) acrylate having a hydroxyl group and (c) a monomer having two or more (meth) acrylate groups. An LED sealing material which is a cured product of the curable composition; an LED element comprising a cured product of the curable composition; and an electronic device, an optical element, and a cured product using the curable composition.

Description

Technical Field

[0001] The present invention relates to a curable composition, a cured product of the curable composition, an LED element including the cured product, an electronic device using the cured product, and an optical element using the cured product. Background Art

[0002] Display devices such as liquid crystal displays, plasma displays, organic EL displays, and small LED displays are widely used. In addition, in recent years, there has been active development of practical micro LED displays that have excellent characteristics such as brightness, color gamut, contrast, and reliability, and can achieve low power consumption by using high-luminous efficiency LEDs as light sources.

[0003] From the viewpoint of maintaining the characteristics of the light-emitting element, various developments have been made on sealing materials. Patent Document 1 discloses a sealing method, that is, in order to suppress the degradation of the characteristics of the organic EL element due to moisture, oxygen, etc., the organic light-emitting material layer and the electrode constituting the organic EL display element are sealed using a laminated film of a silicon nitride film and a resin film formed by a CVD method.

[0004] In addition, as the output of LED increases, heat generation of LED packages becomes a problem, and silicone resins can be used as LED sealing materials instead of epoxy resins that cannot avoid yellowing. Patent document 2 discloses a thermosetting resin composition, a cured product thereof, and a composition for optical semiconductors containing the thermosetting resin composition, wherein the thermosetting resin composition contains a thermosetting resin composed of specific silsesquioxane and organopolysiloxane.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2000-223264

[0008] Patent Document 2: International Publication No. 2014 / 077216 Summary of the invention

[0009] Problems to be solved by the invention

[0010] In electronic devices using light-emitting elements such as LEDs, such as backlights and displays, sealing materials require reliability such as heat resistance of the light-emitting elements, heat resistance of the light emitted, light resistance, and moisture resistance in high humidity environments, as well as transparency and adhesion. As a result, the requirements for sealing materials for LEDs are becoming increasingly stringent, requiring transparent sealing materials that can cope with the high output of LEDs, high performance of micro-LED displays, etc., and have both heat resistance, light resistance, and moisture resistance, and excellent adhesion to the substrate. In addition, there is still room for improvement.

[0011] On the other hand, regarding the composition itself as a sealing material, in addition to the manufacturing cost of the compound to be formulated, there are also requirements for environmental considerations, responses to thinner displays, further simplification of the manufacturing process, and improvement of safety. From these viewpoints, a solvent-free composition that can be applied by an inkjet method and does not require annealing treatment is required.

[0012] The present inventors have conducted intensive studies and have found that a curable composition comprising specific polymerizable monomers has excellent curability and can be formed into a molded product by an inkjet method. In addition, the obtained cured product has excellent physical properties such as heat resistance, light resistance, moisture resistance and transparency.

[0013] An object of the present invention is to provide a curable composition capable of forming a cured product having excellent curability and storage stability, and excellent heat resistance, light resistance, moisture resistance, transparency and adhesion to a substrate by an inkjet method.

[0014] Another object of the present invention is to provide an LED sealing material, which is a cured product of the curable composition; an LED element, which includes the cured product of the curable composition; and an electronic device and an optical element, which use the cured product of the curable composition.

[0015] Solution to the problem

[0016] The present invention has the following aspects.

[0017] [1] A curable composition comprising as essential components a (meth)acrylate having a hydroxyl group (a) and a monomer having two or more (meth)acrylate groups (c).

[0018] [2] A curable composition comprising the following components (a) to (c) as essential components:

[0019] (Meth)acrylate having a hydroxyl group (a)

[0020] (Meth)acrylate having a phosphoric acid group (b)

[0021] - A monomer (c) having two or more (meth)acrylate groups.

[0022] [3] The curable composition according to [1] or [2], further comprising (meth)acrylate (d) having a cyclic skeleton.

[0023] [4] The curable composition according to [3], wherein the (meth)acrylate (d) having a cyclic skeleton is at least one selected from the group consisting of (meth)acrylate (d1) having a cyclic skeleton containing a heteroatom and (meth)acrylate (d2) having a carbocyclic skeleton.

[0024] [5] The curable composition according to any one of [1] to [4], comprising 5 to 50% by mass of the monomer (c) having two or more (meth)acrylate groups, based on the total mass of the composition.

[0025] [6] The curable composition according to any one of [1] to [5], wherein the monomer (c) having two or more (meth)acrylate groups is a monomer having three or more (meth)acrylate groups.

[0026] [7] The curable composition according to any one of [1] to [6], comprising 10 to 50% by mass of the (meth)acrylate (a) having a hydroxyl group, based on the total mass of the composition.

[0027] [8] The curable composition according to any one of [2] to [7], comprising 0.01 to 10% by mass of the (meth)acrylate (b) having a phosphoric acid group, based on the total mass of the composition.

[0028] [9] The curable composition according to any one of [1] to [8], further comprising a photopolymerization initiator.

[0029]

[10] The curable composition according to any one of [1] to [9], which is an active energy ray-curable composition.

[0030]

[11] The curable composition according to any one of [1] to

[10] , which has a viscosity at 25°C of 3 to 30 mPa·s.

[0031]

[12] The curable composition according to any one of [1] to

[11] , which does not contain a solvent.

[0032]

[13] The curable composition according to any one of [1] to

[12] , which is a composition for an LED sealing material.

[0033]

[14] The curable composition according to any one of [1] to

[13] , which is molded by an inkjet method.

[0034]

[15] A cured product of the curable composition according to any one of [1] to

[14] .

[0035]

[16] The cured product according to

[15] , which is an LED sealing material.

[0036]

[17] An LED element comprising a cured product of the curable composition according to any one of [1] to

[14] .

[0037]

[18] An electronic device using a cured product of the curable composition according to any one of [1] to

[14] .

[0038]

[19] An optical element using a cured product of the curable composition according to any one of [1] to

[14] .

[0039] Effects of the Invention

[0040] According to the present invention, there is provided a curable composition which can form a cured product having excellent curability and storage stability, as well as excellent heat resistance, light resistance, moisture resistance, transparency, and adhesion to a substrate by an inkjet method. In addition, according to the present invention, there is provided an LED sealing material which is a cured product of the curable composition; an LED element which includes the cured product of the curable composition; and an electronic device and an optical element which use the cured product of the curable composition. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a diagram schematically showing a configuration example of a micro LED display as one embodiment of an electronic device using a cured product of the curable composition of the present invention as a sealing material. DETAILED DESCRIPTION

[0042] The present invention provides a curable composition comprising (meth)acrylate (a) having a hydroxyl group and a monomer (c) having two or more (meth)acrylate groups as essential components.

[0043] In addition, the present invention is a curable composition comprising the following components (a) to (c) as essential components:

[0044] (Meth)acrylate having a hydroxyl group (a)

[0045] (Meth)acrylate having a phosphoric acid group (b)

[0046] - A monomer (c) having two or more (meth)acrylate groups.

[0047] Hereinafter, the curable composition of the present invention may also be simply referred to as "the present curable composition".

[0048] The present curable composition preferably further contains a (meth)acrylate (d) having a cyclic skeleton, and the (meth)acrylate (d) having a cyclic skeleton is preferably one or more selected from the group consisting of (meth)acrylates (d1) having a cyclic skeleton containing a heteroatom and (meth)acrylates (d2) having an aromatic ring.

[0049] In this specification, "(meth)acrylate" is a term collectively referring to acrylate, methacrylate, and both of them. "(Meth)acrylic acid" is a term collectively referring to acrylic acid, methacrylic acid, and both of them. "(Meth)acryloyloxy" is a term collectively referring to acryloxy, methacryloyloxy, and both of them.

[0050] The curable composition of the present invention is excellent in curability and storage stability. In addition, a cured product excellent in heat resistance, light resistance, moisture resistance, transparency, and adhesion to a substrate can be formed from the curable composition by an inkjet method.

[0051] The structure of the present curable composition will be described below.

[0052] In the present curable composition, examples of the (meth)acrylate (a) having a hydroxyl group include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-ethylhexyldiglycol (meth)acrylate, diethylene glycol mono(meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 1,4-cyclohexanedimethanol monoacrylate, 1-(acryloyloxy)-3-(methacryloyloxy)-2-propanol, pentaerythritol triacrylate, etc. Among these, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and pentaerythritol triacrylate are preferred, and 4-hydroxybutyl acrylate is more preferred, from the viewpoints of wide application, availability at a low price, good curability, inkjet ejectability, and excellent various physical properties of the cured product after curing, such as moisture resistance and heat resistance. By containing the (meth)acrylate (a) having a hydroxyl group, the moisture resistance and heat resistance of the cured product formed from the present curable composition are improved.

[0053] The content of the (meth)acrylate (a) having a hydroxyl group in the present curable composition is preferably 10% by mass or more, more preferably 15% by mass or more, and further preferably 20% by mass or more relative to the overall mass of the curable composition. The content of the (meth)acrylate (a) having a hydroxyl group is preferably 50% by mass or less, more preferably 45% by mass or less, more preferably 40% by mass or less, and further preferably 35% by mass or less relative to the overall mass of the curable composition. In other words, the content of the (meth)acrylate (a) having a hydroxyl group in the present curable composition is preferably in the range of 10 to 50% by mass, more preferably in the range of 15 to 45% by mass, more preferably in the range of 20 to 40% by mass, and further preferably in the range of 20 to 35% by mass.

[0054] If the curable composition contains the (meth)acrylate (a) having a hydroxyl group within this range, the curability of the curable composition becomes good, and the storage stability of the curable composition and the moisture resistance and heat resistance of the cured product after curing are improved. In addition, the performance of the cured product formed from the curable composition, such as adhesion to the substrate, is improved.

[0055] In the present curable composition, examples of the (meth)acrylate (b) having a phosphate group include alkylene phosphate (meth)acrylates such as methylene phosphate (meth)acrylate, ethylene phosphate (meth)acrylate, propylene phosphate (meth)acrylate, and tetramethylene phosphate (meth)acrylate, phosphate esters of polyethylene glycol monoacrylate, phosphate esters of polypropylene glycol monomethacrylate, or phosphate-containing compounds represented by the following general formula (b1).

[0056]

[0057] [In formula (b1), R 1 represents a hydrogen atom or a methyl group. 2 represents a linear or branched alkylene group having 1 to 4 carbon atoms. 3 represents a divalent organic group. s is an integer of 0 to 3, t is an integer of 1 to 6, and u is a positive number of 1 to 2.]

[0058] R in the general formula (b1) 2 Preferred are linear or branched alkylene groups having 2 or 3 carbon atoms, and examples thereof include methylene [-CH2-], ethylene [-(CH2)2-], trimethylene [-(CH2)3-], -CH(CH3)-, -CH(CH2CH3)-, and -C(CH3)2-.

[0059] As R in the general formula (b1) 3The divalent organic group represented by the present invention includes a saturated or unsaturated divalent aliphatic hydrocarbon group having 1 to 12 carbon atoms, a divalent aromatic hydrocarbon group having 6 to 12 carbon atoms, or a divalent linking group containing a heteroatom. These groups may also have a substituent. As the substituent, a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, a carbonyl group, etc. may be mentioned.

[0060] The above-mentioned divalent aliphatic hydrocarbon group may be straight-chain or branched, and examples thereof include alkylene groups such as methylene, ethylene, trimethylene, tetramethylene [-(CH2)4-], and pentamethylene [-(CH2)5-]; alkylmethylene groups such as -CH(CH3)-, -CH(CH2CH3)-, -C(CH3)2-, -C(CH3)(CH2CH3)-, -C(CH3)(CH2CH2CH3)-, and -C(CH2CH3)2-; -CH(C H3)CH2-, -CH(CH3)CH(CH3)-, -C(CH3)2CH2-, -CH(CH2CH3)CH2-, -C(CH2CH3)2-CH2- and the like alkylethylene; -CH(CH3)CH2CH2-, -CH2CH(CH3)CH2- and the like alkyltrimethylene; -CH(CH3)CH2CH2CH2-, -CH2CH(CH3)CH2- and the like alkyltetramethylene; and the like alkylalkylene.

[0061] Examples of the heteroatom-containing divalent linking group include -O-, -C(=O)-O-, -OC(=O)-, -C(=O)-, -OC(=O)-O-, -C(=O)-NH-, -NH-, -S-, -S(=O)2-, and -S(=O)2-O-.

[0062] Among them, as R 3 , preferably a linear or branched alkylene group, an ester bond [—C(═O)—O—, —OC(═O)—], an ether bond (—O—), or a combination thereof.

[0063] Specific examples of the (meth)acrylate (b) having a phosphoric acid group represented by the general formula (b1) are shown below. 1 and u are the same as defined above.

[0064]

[0065] As the (meth)acrylate (b) having a phosphate group, commercially available products can be used, for example, the product name "EBECRYL168" manufactured by Daicel Allnex, the product names "KAYAMER PM-2" and "KAYAMER PM-21" manufactured by Nippon Kayaku Co., Ltd.; the product names "Hosmer M", "Hosmer PE", and "Hosmer PP" manufactured by Unichemical Co., Ltd.; "Light Ester P-1M", "Light Acrylate P-1A(N)", and "Light Ester P-2M" manufactured by Kyoeisha Chemical Co., Ltd.; and "JPA-514" manufactured by Johoku Chemical Industry Co., Ltd.

[0066] The (meth)acrylate (b) having a phosphoric acid group may be used alone or in combination of two or more.

[0067] When the curable composition contains a (meth) acrylate (b) having a phosphate group, the content thereof is preferably 0.01% by mass or more relative to the overall mass of the curable composition, more preferably 0.02% by mass or more, more preferably 0.03% by mass or more, more preferably 0.05% by mass or more, more preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and further preferably 0.5% by mass or more. The content of the (meth) acrylate (b) having a phosphate group is preferably 10% by mass or less relative to the overall mass of the curable composition, more preferably 8% by mass or less, more preferably 8% by mass or less, more preferably 5% by mass or less, more preferably 3% by mass or less, more preferably 2% by mass or less, more preferably 1% by mass or less, and further preferably 0.8% by mass or less. In other words, when the present curable composition contains a (meth)acrylate (b) having a phosphate group, the content thereof is preferably in the range of 0.01 to 10% by mass, more preferably in the range of 0.02 to 8% by mass, and still more preferably in the range of 0.03 to 5% by mass, relative to the total mass of the present curable composition.

[0068] When the curable composition contains the (meth)acrylate (b) having a phosphoric acid group within this range, the curability of the curable composition becomes favorable, and the performance such as adhesion to a substrate of a cured product formed from the curable composition is improved.

[0069] Examples of the monomer (c) having two or more (meth)acrylate groups in the curable composition include ethylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 3-methyl-1,5-pentanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 2-methyl-1,8-octanediol di(meth)acrylate, Diol di(meth)acrylates such as 2-butyl-2-ethyl-1,3-propanediol di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, ethoxylated (2) neopentyl glycol di(meth)acrylate [a compound obtained by esterifying a 2-mol adduct of ethylene oxide with di(meth)acrylate] and propoxylated (2) neopentyl glycol di(meth)acrylate [a compound obtained by esterifying a 2-mol adduct of propylene oxide with di(meth)acrylate];

[0070] Alkylene glycol di(meth)acrylates such as diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, tetrapropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polytetramethylene glycol di(meth)acrylate, and bis(4-acryloxypolyethoxyphenyl)propane;

[0071] Tris(2-hydroxyethyl)isocyanurate di(meth)acrylate;

[0072] Dihydroxymethyl tricyclodecane di(meth)acrylate, caprolactone-modified hydroxytrimethylacetic acid neopentyl glycol di(meth)acrylate;

[0073] Bisphenol A di(meth)acrylate, propylene oxide modified bisphenol A di(meth)acrylate, ethylene oxide modified bisphenol A di(meth)acrylate, bisphenol F di(meth)acrylate, propylene oxide modified bisphenol F di(meth)acrylate, ethylene oxide modified bisphenol F di(meth)acrylate;

[0074] Trifunctional (meth)acrylates such as pentaerythritol tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolpropane ethylene oxide-modified tri(meth)acrylate, trimethylolpropane propylene oxide-modified tri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, modified glycerol tri(meth)acrylate, propylene oxide adduct tri(meth)acrylate of glycerol, and ethylene oxide adduct tri(meth)acrylate of glycerol;

[0075] Tetrafunctional (meth)acrylates such as pentaerythritol tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, and tetramethylolmethane tetra(meth)acrylate;

[0076] Hexafunctional (meth)acrylates such as dipentaerythritol hexa(meth)acrylate and caprolactone-modified dipentaerythritol hexa(meth)acrylate, and the like.

[0077] The monomer (c) having two or more (meth)acrylate groups may be used alone or in combination of two or more.

[0078] The content of the monomer (c) having two or more (meth) acrylate groups in the present curable composition is preferably 5% by mass or more relative to the overall mass of the present curable composition, more preferably 8% by mass or more, and further preferably 10% by mass or more. The content of the monomer (c) having two or more (meth) acrylate groups is preferably 50% by mass or less relative to the overall mass of the present curable composition, more preferably 45% by mass or less, more preferably 40% by mass or less, more preferably 30% by mass or less, more preferably 20% by mass or less, and further preferably 15% by mass or less. In other words, the content of the monomer (c) having two or more (meth) acrylate groups in the present curable composition is preferably in the range of 5 to 50% by mass relative to the overall mass of the present curable composition, more preferably in the range of 5 to 45% by mass, more preferably in the range of 5 to 40% by mass, more preferably in the range of 5 to 30% by mass, more preferably in the range of 5 to 20% by mass, and further preferably in the range of 5 to 15% by mass.

[0079] When the curable composition contains the monomer (c) having two or more (meth)acrylate groups within this range, the curability of the curable composition becomes good, and the performance of the cured product formed from the curable composition, such as flexibility and adhesion to a substrate, is improved.

[0080] In addition, when a single compound is used as the monomer (c) having two or more (meth)acrylate groups, for example, when a monomer having three or more (meth)acrylate groups such as the above-mentioned trifunctional (meth)acrylates and tetrafunctional (meth)acrylates such as trimethylolpropane ethylene oxide-modified triacrylate is used, the performance of the cured product formed from the present curable composition, such as the flexibility and adhesion to the substrate, can be effectively improved.

[0081] When two or more compounds are used in combination as the monomer (c) having two or more (meth)acrylate groups, it is also preferred to use in combination a monomer having three or more (meth)acrylate groups, such as the trifunctional (meth)acrylate and tetrafunctional (meth)acrylate exemplified above, from the viewpoint of being able to effectively improve the performance of the cured product formed from the present curable composition, such as the flexibility and adhesion to the substrate. In this case, the content of the monomer having three or more (meth)acrylate groups in the monomer (c) having two or more (meth)acrylate groups is preferably 10% by mass or more, and all of the monomers may be monomers having three or more (meth)acrylate groups.

[0082] This curable composition can also further contain (meth) acrylate (d) with cyclic skeleton. If (meth) acrylate (d) with cyclic skeleton is included, it is easy to adjust the viscosity of this curable composition to a suitable viscosity range when formed by inkjet method. In addition, the shrinkage of the cured product formed from this curable composition decreases, and excellent adhesion etc. With regard to these viewpoints, it is preferred to further contain (meth) acrylate (d) with cyclic skeleton.

[0083] It should be noted that, in this specification, a (meth)acrylate having a hydroxyl group and a cyclic skeleton is classified as a (meth)acrylate having a hydroxyl group (a), and a (meth)acrylate having a phosphate group and a cyclic skeleton is classified as a (meth)acrylate having a phosphate group (b). In addition, a monomer having two or more (meth)acrylate groups, whether or not it has a cyclic skeleton, is classified as a (meth)acrylate having a hydroxyl group (a) or a (meth)acrylate having a phosphate group (b) when it has one or more hydroxyl groups or a phosphate group, and is classified as a monomer having two or more (meth)acrylate groups (c) when it does not have either a hydroxyl group or a phosphate group.

[0084] In other words, the (meth)acrylate (d) having a cyclic skeleton has a cyclic skeleton and includes a mono(meth)acrylate having neither a hydroxyl group nor a phosphoric acid group.

[0085] The (meth)acrylate (d) having a cyclic skeleton is preferably at least one selected from the group consisting of (meth)acrylate (d1) having a cyclic skeleton containing a heteroatom and (meth)acrylate (d2) having a carbocyclic skeleton.

[0086] Examples of the (meth)acrylate (d1) having a cyclic skeleton containing a hetero atom include (meth)acryloylmorpholine, N-(meth)acryloyloxyethylhexahydrophthalimide, tetrahydrofurfuryl (meth)acrylate, and cyclic trimethylolpropane formal (meth)acrylate.

[0087] Examples of the (meth)acrylate (d2) having a carbon ring skeleton include mono(meth)acrylates having a cyclic aliphatic group such as cyclohexyl(meth)acrylate, 4-tert-butylcyclohexyl(meth)acrylate, tricyclodecane dimethanol mono(meth)acrylate, adamantyl(meth)acrylate, cyclohexanedimethanol mono(meth)acrylate, trimethylcyclohexyl(meth)acrylate, isobornyl(meth)acrylate, tert-butylcyclohexyl(meth)acrylate, dicyclopentanyl(meth)acrylate, and dicyclopentenyloxyethyl(meth)acrylate; and mono(meth)acrylates having an aromatic hydrocarbon group such as 2-phenoxyethyl(meth)acrylate and benzyl(meth)acrylate.

[0088] The (meth) acrylate (d) with a cyclic skeleton can be used alone or in combination with two or more thereof. From the viewpoint of excellent heat resistance of the cured product after curing, the (meth) acrylate (d) with a cyclic skeleton is preferably a (meth) acrylate (d2) containing a carbocyclic skeleton. In particular, when the curable composition does not include a (meth) acrylate (b) with a phosphate group but includes a (meth) acrylate (d) with a cyclic skeleton, the content of the (meth) acrylate (d2) with a carbocyclic skeleton in the (meth) acrylate (d) with a cyclic skeleton is preferably 50% by mass or more, and all of them can be (meth) acrylates (d2) with a carbocyclic skeleton.

[0089] From the viewpoint of excellent safety, wide application, availability at a low price, excellent inkjet discharge properties, good curability, and excellent adhesion of the cured product to the substrate, as the (meth)acrylate (d1) having a cyclic skeleton containing a heteroatom, more preferably tetrahydrofurfuryl (meth)acrylate and cyclic trimethylolpropane formal (meth)acrylate are preferred, and as the (meth)acrylate (d2) having a carbocyclic skeleton, more preferably 2-phenoxyethyl (meth)acrylate, isobornyl (meth)acrylate, 3,3,5-trimethylcyclohexyl acrylate, and tert-butylcyclohexyl acrylate are preferred.

[0090] In the present curable composition, as the (meth)acrylate (d) having a cyclic skeleton, it is further preferred to use two or more selected from four compounds including tetrahydrofurfuryl acrylate, cyclic trimethylolpropane formal acrylate, 2-phenoxyethyl acrylate, and 3,3,5-trimethylcyclohexyl acrylate.

[0091] In the case where the curable composition contains a (meth) acrylate (d) having a cyclic skeleton, its content is preferably 30% by mass or more relative to the overall mass of the curable composition, more preferably 35% by mass or more, more preferably 40% by mass or more, more preferably 45% by mass or more, and further preferably 50% by mass or more. The content of the (meth) acrylate (d) having a cyclic skeleton is preferably 80% by mass or less relative to the overall mass of the curable composition, more preferably 75% by mass or less, further preferably 70% by mass or less, further more preferably 65% ​​by mass or less, and particularly preferably 60% by mass or less. In other words, in the case where the curable composition contains a (meth) acrylate (d) having a cyclic skeleton, its content is preferably in the range of 30 to 80% by mass relative to the overall mass of the curable composition, more preferably in the range of 30 to 70% by mass, more preferably in the range of 40 to 70% by mass, more preferably in the range of 50 to 70% by mass, and further preferably in the range of 50 to 65% by mass.

[0092] When the curable composition contains the (meth)acrylate (d) having a cyclic skeleton within the above range, the curability of the curable composition becomes favorable, and the storage stability thereof, the performance of the formed cured product, and the like are improved.

[0093] In addition, when the (meth)acrylate (d) having a cyclic skeleton contains both the (meth)acrylate (d1) having a cyclic skeleton containing heteroatoms and the (meth)acrylate (d2) having a carbocyclic skeleton, the content ratio thereof is not particularly limited. However, from the viewpoint of excellent inkjet ejection properties, good curability, and adhesion of the cured product to the substrate, the proportion of the (meth)acrylate (d1) having a cyclic skeleton containing heteroatoms is preferably 50% by mass or more, and from the viewpoint of better heat resistance of the cured product after curing, the proportion of the (meth)acrylate (d2) having a carbocyclic skeleton in the (meth)acrylate (d) having a cyclic skeleton is preferably 50% by mass or more.

[0094] In particular, in order to obtain good inkjet ejection properties, good curing properties, good adhesion to the substrate of the cured product after curing, and excellent heat resistance of the cured product after curing in a well-balanced manner, the ratio of the (meth)acrylate (d2) having a carbocyclic skeleton in the (meth)acrylate (d) having a cyclic skeleton is preferably in the range of 20 to 70 mass %, more preferably in the range of 25 to 70 mass %, and further preferably in the range of 30 to 65 mass %.

[0095] The present curable composition may further contain other polymerizable compounds different from the above-mentioned (meth)acrylate having a hydroxyl group (a), (meth)acrylate having a phosphate group (b), monomer having two or more (meth)acrylate groups (c), and (meth)acrylate having a cyclic skeleton (d).

[0096] Examples of other polymerizable compounds include monofunctional polymerizable compounds and polymerizable compounds having two or more polymerizable groups (hereinafter referred to as "polyfunctional polymerizable compounds"). Here, the polymerizable group refers to a group having a polymerizable unsaturated double bond.

[0097] The monofunctional polymerizable compound is preferably a compound having a polymerizable unsaturated double bond and being liquid at 25° C. The molecular weight thereof is preferably 60 to 2,000, more preferably 100 to 1,000.

[0098] The viscosity of the monofunctional polymerizable compound is preferably 1000 mPa·s or less, more preferably 300 mPa·s or less. The viscosity is preferably 1 mPa·s or more, more preferably 3 mPa·s or more.

[0099] Examples of the monofunctional polymerizable compound of the other polymerizable compound include polymerizable compounds having a heterocyclic structure, monofunctional (meth)acrylates having a chain aliphatic group, monofunctional (meth)acrylates having an alkyleneoxy group, and monovinyl ether compounds.

[0100] Examples of the polymerizable compound having a heterocyclic structure include N-vinylcaprolactam, N-vinylpyrrolidone, and N-vinylformamide.

[0101] Examples of the monofunctional (meth)acrylate having a chain aliphatic group include isoamyl (meth)acrylate, stearyl (meth)acrylate, lauryl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, decyl (meth)acrylate, isomyristyl (meth)acrylate, and isostearyl (meth)acrylate.

[0102] Examples of the monofunctional (meth)acrylate having an alkyleneoxy group include methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate, butoxyethyl (meth)acrylate, ethoxyethoxyethyl (meth)acrylate, diethylene glycol monobutyl ether (meth)acrylate, methoxydiethylene glycol (meth)acrylate, methoxytriethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, and methoxypropylene glycol (meth)acrylate.

[0103] Examples of the monovinyl ether compound include ethylene glycol monovinyl ether, triethylene glycol monovinyl ether, hydroxyethyl monovinyl ether, ethyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, octadecyl vinyl ether, cyclohexyl vinyl ether, hydroxybutyl vinyl ether, 2-ethylhexyl vinyl ether, hydroxynonyl monovinyl ether, cyclohexanedimethanol monovinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, isopropenyl vinyl ether, dodecyl vinyl ether, diethylene glycol monovinyl ether, phenyl glycidyl ether, butyl glycidyl ether, and 2-ethylhexyl glycidyl ether.

[0104] The multifunctional polymerizable compound as the above-mentioned other polymerizable compounds may also be any one of a monomer, an oligomer, and a polymer. It should be noted that in the present specification, "monomer" refers to a compound having a molecular weight (weight average molecular weight when there is a molecular weight distribution) of 1000 or less. The molecular weight of the monomer (weight average molecular weight when there is a molecular weight distribution) is 50 to 1000. "Oligomer" refers to a polymer that usually has a constituent unit based on a limited number (usually 5 to 100) of monomers and has a weight average molecular weight greater than 1000 and less than 30000. "Polymer" refers to a polymer having a weight average molecular weight of 30000 or more. The weight average molecular weight is a value obtained by measuring using gel permeation chromatography (GPC) and setting it as a standard polystyrene conversion value.

[0105] Examples of the polyfunctional polymerizable compound include the following general formula (1):

[0106] CH2=CR 4 -COO-R 5 -O-CH=CH-R 6 …(1)

[0107] (Where R 4 represents a hydrogen atom or a methyl group, R 5 represents an organic residue with 2 to 20 carbon atoms, R 6 represents a hydrogen atom or an organic residue having 1 to 11 carbon atoms. ) (hereinafter simply referred to as "monomer (1)"), a divinyl ether compound, a trivinyl ether compound, urethane (meth) acrylate, amino (meth) acrylate, and the like.

[0108] In the general formula (1), R 5The organic residue having 2 to 20 carbon atoms represented may include a linear, branched or cyclic alkylene group having 2 to 20 carbon atoms, an alkylene group having 2 to 20 carbon atoms having an oxygen atom in the structure via an ether bond and / or an ester bond, an aromatic group having 6 to 11 carbon atoms in which the hydrogen atoms bonded to the carbon atoms constituting the ring may be substituted by other substituents, and the like, preferably an alkylene group having 2 to 6 carbon atoms, and an alkylene group having 2 to 9 carbon atoms having an oxygen atom in the structure via an ether bond.

[0109] As R 6 The organic residue having 1 to 11 carbon atoms represented by the above-mentioned group includes a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, an aromatic group having 6 to 11 carbon atoms in which the hydrogen atoms bonded to the carbon atoms constituting the ring may be substituted by other substituents, and the like, preferably an alkyl group having 1 to 2 carbon atoms and an aromatic group having 6 to 8 carbon atoms.

[0110] Specific examples of the monomer (1) include 2-vinyloxyethyl (meth)acrylate, 3-vinyloxypropyl (meth)acrylate, 1-methyl-2-vinyloxyethyl (meth)acrylate, 2-vinyloxypropyl (meth)acrylate, 4-vinyloxybutyl (meth)acrylate, 1-methyl-3-vinyloxypropyl (meth)acrylate, 1-vinyloxymethylpropyl (meth)acrylate, 2-methyl-3-vinyloxypropyl (meth)acrylate, 3-methyl-3-vinyloxypropyl (meth)acrylate, 1,1-dimethyl-2-vinyloxyethyl (meth)acrylate, 3-vinyloxybutyl (meth)acrylate, 1-methyl-2-vinyloxypropyl (meth)acrylate, 2-vinyloxybutyl (meth)acrylate, 4-vinyloxycyclohexyl (meth)acrylate, 5-vinyloxypentyl (meth)acrylate, 6-vinyloxyhexyl (meth)acrylate, 4-vinyloxymethylcyclohexylmethyl (meth)acrylate, and 2-methyl-3-vinyloxypropyl (meth)acrylate. p-vinyloxymethylphenyl methyl acrylate, 2-(vinyloxyethoxy)ethyl (meth)acrylate, 2-(vinyloxyisopropoxy)ethyl (meth)acrylate, 2-(vinyloxyethoxy)propyl (meth)acrylate, 2-(vinyloxyethoxy)isopropyl (meth)acrylate, 2-(vinyloxyisopropoxy)propyl (meth)acrylate, 2-(vinyloxyisopropoxy)isopropyl (meth)acrylate, 2-(vinyloxyisopropoxy)ethyl (meth)acrylate, 2-(vinyloxyethoxyisopropoxy)ethyl (meth)acrylate, 2-(vinyloxyethoxyisopropoxy)propyl (meth)acrylate, 2-(vinyloxyethoxyethoxy)isopropyl (meth)acrylate, 2-(vinyloxyethoxyisopropoxy)isopropyl (meth)acrylate, 2-(vinyloxyethoxyisopropoxy)ethyl (meth)acrylate, polyethylene glycol monovinyl ether, polypropylene glycol monovinyl ether (meth)acrylate. The monomer (1) is preferably 2-(2-vinyloxyethoxy)ethyl (meth)acrylate, and more preferably 2-(2-vinyloxyethoxy)ethyl acrylate, from the viewpoint of low viscosity, high flash point, and excellent curability.

[0111] Examples of the divinyl ether compound or trivinyl ether compound include ethylene glycol divinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether, propylene glycol divinyl ether, dipropylene glycol divinyl ether, butanediol divinyl ether, hexanediol divinyl ether, cyclohexanedimethanol divinyl ether, and trimethylolpropane trivinyl ether.

[0112] Examples of the urethane (meth)acrylate include aliphatic urethane (meth)acrylates, aromatic urethane (meth)acrylates, etc. The weight average molecular weight of the urethane (meth)acrylate is preferably 1,000 to 30,000, more preferably 2,000 to 20,000. As the urethane (meth)acrylate, commercially available products can be used, for example, U-2PPA, U-4HA, U-6HA, U-6LPA, U-15HA, U-324A, UA-122P, UA5201, UA-512, etc. manufactured by Shin-Nakamura Chemical Industry Co., Ltd.; CN965NS, CN964A85, CN964, CN959, CN962, CN963J85, CN965, CN982B88, CN981, CN983, CN996, CN9002, CN9007, CN9009, CN9010, CN9011, CN9178, CN9788, CN9893 manufactured by Sartomer; EBECRYL230, EBECRYL270, EBECRYL8402, EBECRYL8804, EBECRYL8807, EBECRYL9270, KRM8191, etc. manufactured by allnex.

[0113] Amino (meth)acrylate is an amine-modified (meth)acrylate having an amino group. The number average molecular weight of the amino (meth)acrylate is preferably 2,000 to 20,000, more preferably 2,000 to 10,000, and even more preferably 2,000 to 5,000. Commercially available amino (meth)acrylates may be used, for example, EBECRYL7100 and EBECRYL80 manufactured by Daicel Allnex.

[0114] When the curable composition further includes other polymerizable compounds, the other polymerizable compounds may be used alone or in combination of two or more. In addition, the content of the other polymerizable compounds is preferably 30% by mass or less relative to the whole curable composition, more preferably 20% by mass or less, and more preferably 10% by mass or less from the viewpoint that the viscosity of the obtained curable composition and the curing shrinkage in the cured product of the curable composition are easy to adjust.

[0115] The curable composition may be a curable composition cured by heat, or a curable composition cured by active energy rays. From the viewpoint that it can be more suitably used as an LED sealing material described later, the curable composition is preferably a curable composition cured by active energy rays. Therefore, the curable composition may further include a photopolymerization initiator, preferably a photopolymerization initiator.

[0116] Examples of the photopolymerization initiator include 2-methylbenzoyldiphenylphosphine oxide, bis(2,6-dichlorobenzoyl)phenylphosphine oxide, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, (2,4,6-trimethylbenzoyl)diphenylphosphine oxide, 2,6-dimethoxybenzoyldiphenylphosphine oxide, 2,6-dichlorobenzoyldiphenylphosphine oxide, bis(2,6-dichlorobenzoyl)-2,5 - acylphosphine compounds such as dimethylphenylphosphine oxide, bis(2,6-dichlorobenzoyl)-4-propylphenylphosphine oxide, bis(2,6-dichlorobenzoyl)-1-naphthylphosphine oxide, bis(2,6-dimethoxybenzoyl)phenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, and bis(2,6-dimethoxybenzoyl)-2,5-dimethylphenylphosphine oxide;

[0117] Phosphinate compounds such as (2,4,6-trimethylbenzoyl)phenylphosphinate methyl, (2,4,6-trimethylbenzoyl)phenylphosphinate ethyl, (3-benzoyl-2,4,6-trimethylbenzoyl)phenylphosphinate methyl, (3-benzoyl-2,4,6-trimethylbenzoyl)phenylphosphinate ethyl, and trimethylacetylphenylphosphinate isopropyl;

[0118] Benzoin isobutyl ether, 2,4-diethylthioxanthenone [also known as 2,4-diethylthioxanthen-9-one (2,4-Diethylthioxanthen-9-one)], 2-isopropylthioxanthenone, methyl benzoylformate, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butane-1-one, 1-hydroxycyclohexylphenyl ketone, benzoin ethyl ether, benzyl dimethyl ketal, 2-hydroxy-2-methyl-1-phenylpropane-1-one, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropane-1-one 1-{4-[(4-benzoylphenyl)-p-aminobenzenesulfonyl]phenyl}-2-methyl-2-[(4-methylphenyl)sulfone]propane-1-one, 1-{4-[(4-benzoylphenyl)-p-aminobenzenesulfonyl]phenyl}-2-methyl-2-[(4-methylphenyl)sulfone]propane-1-one, and the like.

[0119] Among these, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, (2,4,6-trimethylbenzoyl)diphenylphosphine oxide, (2,4,6-trimethylbenzoyl)phenylphosphinate ethyl, (3-benzoyl-2,4,6-trimethylbenzoyl)phenylphosphinate ethyl, which correspond to the wavelength of light emitted by an ultraviolet light emitting diode (UV-LED) light source as a light source of active energy rays, are preferred. In particular, when a UV-LED having a main peak wavelength of 365 to 405 nm is used as a light source, it is preferred to use an acylphosphine-based compound, particularly phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide or (2,4,6-trimethylbenzoyl)diphenylphosphine oxide as a photopolymerization initiator.

[0120] The photopolymerization initiator may be contained alone or in combination of two or more.

[0121] When the curable composition contains a photopolymerization initiator, the content thereof is preferably 1 to 10% by mass, more preferably 2 to 8% by mass, relative to the entire curable composition. If the content of the photopolymerization initiator is within the above range, the curability and storage stability of the curable composition become good, and the coloring of the formed cured product is suppressed, and there is a tendency that the performance of the cured product is improved.

[0122] When the curable composition contains a photopolymerization initiator, the curable composition may further contain a sensitizer. Examples of the sensitizer include trimethylamine, methyldimethanolamine, triethanolamine, p-diethylaminoacetophenone, ethyl p-dimethylaminobenzoate, isopentyl p-dimethylaminobenzoate, N,N-dimethylbenzylamine, 4,4'-bis(diethylamino)benzophenone, anthracene-9,10-diethyl ether, and 9,10-bis(n-heptanoyloxy)anthracene.

[0123] When the curable composition contains a sensitizer, the content thereof is preferably 0.1 to 10% by mass, more preferably 0.5 to 8% by mass, relative to the total mass of the curable composition. If the content of the sensitizer is within the above range, the curability of the curable composition becomes good, and the coloring of the formed cured product is suppressed, and there is a tendency that the performance of the cured product is improved.

[0124] In addition to the above components, the curable composition may further contain a polymerization inhibitor such as hydroquinone, di-tert-butylhydroquinone, p-methoxyphenol, benzoquinone, dibutylhydroxytoluene, nitrosoamine salts, hindered amine compounds, 2,2,6,6-tetramethylpiperidinyl 1-oxyl (TEMPO) as required. When the polymerization inhibitor is contained, the amount thereof is preferably in the range of 0.01 to 2% by mass relative to the total amount of the curable composition.

[0125] The curable composition may further contain additives such as surfactants, ultraviolet absorbers, antioxidants, surface tension adjusters, anti-fading agents, conductive salts, etc. In addition, from the viewpoint of further improving the adhesion to substrates such as plastic substrates, it may also contain non-reactive resins such as acrylic resins, epoxy resins, terpene phenol resins, rosin esters, etc.

[0126] As described above, the present curable composition contains (meth)acrylate (a) having a hydroxyl group, (meth)acrylate (b) having a phosphoric acid group, and monomer (c) having two or more (meth)acrylate groups as essential components.

[0127] The curable composition preferably further comprises a (meth)acrylate (d) having a cyclic skeleton from the viewpoint that the curability and storage stability of the curable composition are improved, coloration and shrinkage of a cured product formed from the curable composition are suppressed, and performance such as adhesion to a substrate is improved.

[0128] It should be noted that the (meth)acrylate (a) having a hydroxyl group, the (meth)acrylate (b) having a phosphate group, the monomer (c) having two or more (meth)acrylate groups, and the (meth)acrylate (d) having a cyclic skeleton may also be a compound composed of a biomass raw material. In this case, the curable composition itself can be regarded as an environmentally friendly product, which is more preferred from the perspective of reducing environmental burden.

[0129] In addition, from the viewpoint of suppressing the shrinkage of the cured product of the present curable composition and making the performance such as the adhesion with the substrate better, the ratio of the total mass of the (meth) acrylate (d) having a cyclic skeleton to the polymerizable compound component constituting the present curable composition, that is, the (meth) acrylate (a) having a hydroxyl group, the (meth) acrylate (b) having a phosphate group, the monomer (c) having two or more (meth) acrylate groups, the (meth) acrylate (d) having a cyclic skeleton, and other polymerizable compounds contained as required is preferably 30% by mass or more, more preferably 35% by mass or more, more preferably 40% by mass or more, more preferably 45% by mass or more, and further preferably 50% by mass or more. The ratio is preferably 80% by mass or less, more preferably 75% by mass or less, more preferably 70% by mass or less, further more preferably 65% ​​by mass or less, and particularly preferably 60% by mass or less. In other words, the ratio of the (meth)acrylate (d) having a cyclic skeleton to the total mass of the polymerizable compound components constituting the present curable composition is preferably in the range of 30 to 80 mass %, more preferably in the range of 30 to 70 mass %, more preferably in the range of 40 to 70 mass %, more preferably in the range of 50 to 70 mass %, further preferably in the range of 50 to 65 mass %.

[0130] When the ratio of the (meth)acrylate (d) having a cyclic skeleton is within the above range, the curing shrinkage of the curable composition during curing can be reduced, internal stress accumulated in the cured product can be reduced to prevent deformation, and adhesion between the substrate and the cured product can be further ensured.

[0131] In addition, from the perspective of improving the curability of the curable composition and making the physical properties such as the adhesion of the cured product of the curable composition to the substrate better, the monomer (c) having two or more (meth) acrylate groups is preferably 5% by mass or more, more preferably 8% by mass or more, and more preferably 10% by mass or more relative to the total mass of the polymerizable compound components constituting the curable composition, that is, the above-mentioned (meth) acrylate (a) having a hydroxyl group, the (meth) acrylate (b) having a phosphate group, the monomer (c) having two or more (meth) acrylate groups, the (meth) acrylate (d) having a cyclic skeleton, and other polymerizable compounds contained as required. The ratio is preferably 65% ​​by mass or less, more preferably 60% by mass or less, more preferably 55% by mass or less, more preferably 50% by mass or less, more preferably 45% by mass or less, more preferably 40% by mass or less, more preferably 30% by mass or less, more preferably 20% by mass or less, and more preferably 15% by mass or less. In other words, the ratio of the monomer (c) having two or more (meth)acrylate groups to the total mass of the polymerizable compound components constituting the present curable composition is preferably in the range of 5 to 65 mass %, preferably in the range of 5 to 50 mass %, more preferably in the range of 5 to 45 mass %, more preferably in the range of 5 to 40 mass %, more preferably in the range of 5 to 30 mass %, more preferably in the range of 5 to 20 mass %, and even more preferably in the range of 5 to 15 mass %.

[0132] From the viewpoint of being applicable to a wide range of industrial fields, the curable composition may further contain inorganic fillers, various pigments, dyes, etc. Examples of the inorganic filler include carbon black, silicas, aluminum oxide, titanium oxide, zinc oxide, magnesium oxide, calcium carbonate, talc, etc.

[0133] The curable composition may further contain a surfactant from the viewpoint of ensuring operability and discharge stability applicable to the inkjet method and setting the surface tension to a desired range. Examples of the surfactant include anionic surfactants such as dialkyl sulfosuccinates, alkylnaphthalene sulfonates, and fatty acid salts; nonionic surfactants such as polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, acetylene glycols, and polyoxyethylene·polyoxypropylene block copolymers; and cationic surfactants such as alkylamine salts and quaternary ammonium salts.

[0134] In addition, as surfactants, compounds having a polysiloxane chain, silicone-based surfactants having a polyether chain at the side chain or the end and a polysiloxane structure in the main chain; fluorine-based surfactants having a perfluoroalkyl chain, oily fluorine-based compounds (such as fluorine oil) and solid fluorine compound resins (such as tetrafluoroethylene resin) can also be used, preferably hydrophobic organic fluorine compounds.

[0135] When the present curable composition further contains a surfactant, the content thereof is preferably 0.05 to 1% by mass, more preferably 0.1 to 0.8% by mass, based on the entire present curable composition.

[0136] This curable composition can also further contain a leveling agent. Since the leveling agent easily makes the surface of the cured product formed by the self-curing composition smooth, it becomes easy to evenly cure when the cured product is irradiated with ultraviolet light, so the cured product becomes difficult to produce unevenness. As the leveling agent, silane compounds, fluorine compounds, acrylic copolymers, alcohol alkoxylates (alcohol alkoxylate) etc. can be listed. In addition, the above-mentioned surfactant can also be used as a leveling agent.

[0137] The viscosity of the curable composition at 25°C is preferably in the range of 3 to 30 mPa·s, more preferably in the range of 5 to 20 mPa·s. In addition, the surface tension of the curable composition is preferably in the range of 15 to 45 mN / m, more preferably in the range of 20 to 40 mN / m, and further preferably in the range of 25 to 35 mN / m. If the viscosity and surface tension of the curable composition at 25°C are within the above range, it is preferred from the viewpoint of improving the operability of the curable composition and the inkjet discharge stability during inkjet molding.

[0138] Here, this curable composition can also be with the adjustment of above-mentioned viscosity etc. for the purpose, further contain solvent in the scope of not damaging the effect of the present invention, but preferably be solvent-free.In the case of solvent-free, when this curable composition is solidified, the drying step or heat treatment (annealing) for removing solvent can be omitted, and manufacturing process can be simplified.In addition, due to its good curability, it is difficult to produce the outgassing from solvent from cured product, and there is a tendency of safety improvement.Therefore, it is easy to obtain this curable composition that can be coated by inkjet method and does not need annealing.

[0139] The present curable composition can be produced by supplying, stirring and mixing the (meth)acrylate (a) having a hydroxyl group, the (meth)acrylate (b) having a phosphate group, the monomer (c) having two or more (meth)acrylate groups, the (meth)acrylate (d) having a cyclic skeleton, and various optional additional components as required, using a common disperser such as a bead mill or a stirrer.

[0140] Here, as a disperser, in addition to a bead mill, various well-known and commonly used dispersers such as an ultrasonic homogenizer, a high-pressure homogenizer, a paint shaker, a ball mill, a roller mill, a sand mill, a sand grinder, a Dyno-mill, a high-speed disperser (Dispermat), an SC grinder, and a nanomizer can be used.

[0141] As described above, the present curable composition is preferably a curable composition cured by active energy rays. As active energy rays, visible light, ultraviolet rays, infrared rays, microwaves, EUV, semiconductor lasers, excimer lasers (KrF, ArF) and the like can be cited. Among these active energy rays, the present curable composition is more preferably a curable composition cured by light irradiation such as ultraviolet rays.

[0142] As the light source of ultraviolet rays, for example, metal halide lamps, xenon lamps, carbon arc lamps, chemical lamps, low-pressure mercury lamps, high-pressure mercury lamps, UV-LED lamps, etc. can be used. From the viewpoint of generating very little heat and being able to cope with environmental protection of mercury-free, UV-LED lamps can be selected, and it is more preferable to cure by irradiating light using a UV-LED lamp having a main peak wavelength of about 365 to 405 nm as a light source with sufficient illumination.

[0143] The irradiation energy of the UV-LED light is preferably 50 to 3000 mJ / cm 2 The range is more preferably 200 to 2000 mJ / cm 2 range.

[0144] There is no particular restriction on the method of using the curable composition as a sealing material to seal the light-emitting element. For example, the following methods can be cited: dripping the curable composition onto the light-emitting element, and curing it after coating via a spin coater, a die coater, a dispenser, an inkjet method, a stencil printing method, a screen printing method, a gravure printing method, or a mask (mask); using, for example, a dispenser, transfer molding, injection molding, etc. to pre-inject the curable composition into the mold template, and the lead frame of the light-emitting element is fixed therein, and then it is cured after being immersed therein; the curable composition is injected into the template into which the light-emitting element is inserted and cured; the curable composition is injected into the cup (cup) at the bottom of which the light-emitting element is configured using a dispenser, etc., and then cured.

[0145] In addition, the curable composition is applied to a release film using a coating machine or the like in a thickness ranging from sub-micron (0.1 μm) to several hundred μm, and then partially cured to temporarily form a semi-cured film or sheet. The semi-cured film or sheet can also be transferred to a substrate having a light-emitting element fixed thereon, and then cured again to seal the light-emitting element.

[0146] Among them, it is preferably formed by inkjet method using inkjet recording method. In this case, since the droplets of this curable composition can be attached to the object with high position accuracy, the accuracy of the shape and size of the cured product can be improved. In addition, compared with the situation of printing method molding with contact such as screen printing, when the present curable composition is molded by inkjet method, foreign matter is difficult to mix into this curable composition and its cured product, and the yield rate is not easy to deteriorate when making sealed light-emitting elements.

[0147] As the inkjet recording method, any of the conventionally known methods can be used, for example, a method of discharging droplets using vibration of a piezoelectric element (a recording method using an inkjet head that forms ink droplets by mechanical deformation of an electrostrictive element) or a method using thermal energy.

[0148] The present curable composition is appropriately discharged and molded by an inkjet method, and then appropriately irradiated with ultraviolet rays as active energy rays to cure the composition, thereby producing a cured product.

[0149] The curable composition is preferably a composition for a sealing material of a light-emitting element such as an organic EL element or an LED element, and more preferably a composition for an LED sealing material. That is, one embodiment of the present invention is an LED element comprising a cured product of the curable composition. Among them, the curable composition can be preferably used as a sealing material for a micro LED element.

[0150] In addition, an electronic device using a cured product of the present curable composition is also one embodiment of the present invention. By using a cured product of the present curable composition, the accuracy of the size and shape of the electronic device can be improved, and the physical properties of the cured product of the present curable composition can be exerted.

[0151] Examples of the electronic device include displays, mobile terminals, watches, monitors, and other display devices, touch panels, or lighting that use light-emitting elements such as LED elements, micro-LED elements, organic EL elements, and organic light-emitting elements (OLED); conductive films, organic semiconductor devices, solar cells, organic solar cells, organic photoreceptors (OPCs), organic transistors, and the like.

[0152] The present curable composition can also be used to produce a cured product having a concavo-convex shape such as a lens shape. That is, an optical element using a cured product of the present curable composition is also one embodiment of the present invention.

[0153] As the optical element, for example, a light guide plate having a microlens formed on the surface in a mobile terminal such as a liquid crystal backlight device or a smart phone can be cited. By using the cured product of the curable composition, the accuracy of the size and shape of the optical element can be improved, and the physical properties of the cured product of the curable composition can be exerted.

[0154] Specifically, after the curable composition is discharged and molded by an inkjet method, it is irradiated with active energy rays and cured, thereby manufacturing a microlens with a lens diameter of 10 μm and excellent dimensional accuracy of lens height. Alternatively, an electroforming mold can be made by using a microlens original plate made of a cured product of the curable composition, and the electroforming mold can be used to manufacture a molded product (optical element) having a microlens fine structure on the surface.

[0155] It should be noted that the application of the present curable composition is not limited to the above-mentioned electronic devices and optical elements. The present curable composition can be suitably used for manufacturing various products utilizing its characteristics.

[0156] Figure 1 An example of the configuration of a micro LED display as an electronic device using a cured product of the present curable composition is schematically shown, but the present invention is not limited thereto. For example, the present curable composition can also be applied to a display disclosed in US Patent Registration No. 10978626.

[0157] exist Figure 1 In the figure, the micro LED display 100 includes a substrate 2, a micro LED element 1 arranged on the substrate 2, a sealing material 3, a joint 4 between the micro LED element 1 and a metal wiring portion (not shown) formed on the surface of the substrate 2, a partition 5, and a black layer 6 covering the upper portion of the partition 5.

[0158] The micro LED display 100 includes a plurality of micro LED elements 1, and the plurality of micro LED elements 1 are separated from adjacent micro LED elements 1 by spacers 5 on a substrate 2. The sealing material 3 is a cured product of the present curable composition.

[0159] As the substrate 2, for example, a film made of a transparent inorganic material such as glass, or a heat-resistant resin material such as polyethylene naphthalate, polyamide, or polyimide can be used. The thickness of the substrate 2 is not particularly limited, but from the perspective of balance among heat resistance, insulation, and manufacturing cost, in the case of a film, it is generally preferably in the range of 25 to 125 μm.

[0160] The manufacture of the micro LED display 100 is carried out, for example, as follows. First, a substrate 2 is prepared, and a plurality of micro LED elements 1 are mounted on one surface of the substrate 2. Next, a partition 5 is made on one surface of the substrate 2, for example, using a photosensitive resin material by photolithography or inkjet. Next, the curable composition is molded by, for example, an inkjet method to make a coating film, and then the coating film of the curable composition is irradiated with ultraviolet rays to cure it, thereby making a sealing material 3. The coating film of the curable composition can be irradiated with ultraviolet rays in an environment containing oxygen such as an atmospheric environment, or in an inactive environment such as a nitrogen environment.

[0161] The thickness of the sealing material 3 in the micro LED display 100 is usually preferably in the range of 5 to 100 μm, and more preferably in the range of 10 to 50 μm. By thinning the sealing material 3, the micro LED display 100 can be thinned and flexible. It should be noted that the thickness of the sealing material 3 refers to the distance from the outermost surface of the sealing material 3 or the interface with the substrate opposite thereto to the outermost surface on the side different from the surface or the other same interface opposite thereto.

[0162] The above is a description of one embodiment of the present curable composition, the cured product of the present curable composition, the LED element including the cured product, and the electronic device using the cured product, but the present invention is not limited to the configuration of the above embodiment. For example, the present curable composition may be supplemented with any other configuration in the configuration of the above embodiment, or may be replaced with any configuration that produces the same effect.

[0163] Example

[0164] The present invention will be described in detail below with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples and the like.

[0165] The compounds used in the present examples and the like are shown below.

[0166] <(Meth)acrylate having a hydroxyl group (a)>

[0167] a-1: 4-HBA (trade name, manufactured by Osaka Organic Chemical Industry Co., Ltd., 4-hydroxybutyl acrylate)

[0168] a-2: HPA (trade name, manufactured by Osaka Organic Chemical Industry Co., Ltd., hydroxypropyl acrylate)

[0169] a-3: Miramer M340 (trade name, manufactured by MIWON, pentaerythritol triacrylate)

[0170] <(Meth)acrylate having a phosphoric acid group (b)>

[0171] b-1: KAYAMER PM-2 (trade name, manufactured by Nippon Kayaku Co., Ltd.)

[0172] b-2: Light Acrylate P-1A(N) (trade name, manufactured by Kyoeisha Chemical Co., Ltd., 2-acryloyloxyethyl acid phosphate)

[0173] <Monomer (c) having two or more (meth)acrylate groups>

[0174] c-1: Miramer M240 (trade name, manufactured by MIWON, ethylene oxide-modified bisphenol A diacrylate)

[0175] c-2: Miramer M3130 (trade name, manufactured by MIWON, trimethylolpropane ethylene oxide-modified triacrylate)

[0176] c-3: Miramer M210 (trade name, manufactured by MIWON, hydroxypivalate neopentyl glycol diacrylate)

[0177] c-4: Miramer M360 (trade name, manufactured by MIWON, trimethylolpropane propylene oxide addition triacrylate)

[0178] <(Meth)acrylate (d1) having a heteroatom-containing cyclic skeleton>

[0179] d1-1: Viscoat 150 (trade name, manufactured by Osaka Organic Chemical Industry Co., Ltd., tetrahydrofurfuryl acrylate)

[0180] d1-2: Viscoat 200 (trade name, manufactured by Osaka Organic Chemical Industry Co., Ltd., cyclic trimethylolpropane formal acrylate)

[0181] <(Meth)acrylate having a carbon ring skeleton (d2)>

[0182] d2-1: Light Acrylate PO-A (trade name, manufactured by Kyoeisha Chemical Co., Ltd., phenoxyethyl acrylate)

[0183] d2-2: Isobornyl acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd.)

[0184] d2-3: Viscoat 196 (trade name, manufactured by Osaka Organic Chemical Industry Co., Ltd., 3,3,5-trimethylcyclohexyl acrylate)

[0185] d2-4: Miramer M1150 (trade name, manufactured by MIWON, tert-butyl cyclohexyl acrylate)

[0186] <Photopolymerization initiator>

[0187] TPO-H: (2,4,6-trimethylbenzoyl) diphenylphosphine oxide; (manufactured by IGM RESINS BV)

[0188] Omnirad 819: Phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (acylphosphine oxide system; manufactured by IGMRESINS BV)

[0189] <Polymerization inhibitor>

[0190] NONFLEX Alba: 2,5-di-tert-butylhydroquinone (manufactured by Seiko Chemical Co., Ltd.)

[0191] <Additives (leveling agents)>

[0192] KF-352: Polyether-modified polysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd.)

[0193] Production Examples 1 to 21

[0194] 1. Preparation of curable composition

[0195] According to the mixing ratio described in Table 1, each component was put into a container and stirred and mixed to prepare curable compositions 1 to 21.

[0196] 2. Evaluation

[0197] 2-1. Viscosity of curable composition

[0198] The viscosity was measured using an E-type viscometer (TVE-25L: manufactured by Toki Sangyo Co., Ltd.) at a temperature of 25° C. The viscosity of each curable composition is shown in Table 1 using the following evaluation indexes.

[0199] [Evaluation indicators]

[0200] A: 20 mPa·s or less.

[0201] B: greater than 20 mPa·s and not more than 30 mPa·s.

[0202] C: greater than 30 mPa·s.

[0203] In addition, when each curable composition was stored at -20 to 20°C, the viscosity change was small and the storage stability was good.

[0204] 2-2. Light transmittance of cured product

[0205] The curable composition obtained in each manufacturing example was applied to an alkali-free glass substrate (35 mm long × 35 mm wide, 0.7 mm thick) using a spin coater in a film thickness of 10 μm to prepare a coating film. A UV-LED irradiation device (manufactured by AI TecSystem Co., Ltd.) was used with a peak wavelength of 385 nm and a peak illuminance of 500 mW / cm 2 , cumulative light intensity 3J / cm 2 The coating film was irradiated with ultraviolet rays under the conditions of to cure it, thereby producing a cured product (cured coating film). Each cured product was almost transparent.

[0206] (2) The light transmittance of each of the cured products obtained above at a wavelength of 400 to 800 nm was measured using a spectrum meter ("LCD-5200" manufactured by Otsuka Electronics Co., Ltd.) It should be noted that the measured light transmittance of only the alkali-free glass substrate used in preparing the cured product was used as a reference value.

[0207] Table 1 shows the light transmittance values ​​of each cured product at 550 nm.

[0208] 2-3. Adhesion of cured product

[0209] A cured product (cured coating film) of the curable composition obtained in each Production Example was prepared in the same manner as in 2-2(1), and a cross-shaped cut was made on the surface with a cutter. Then, an adhesive tape (manufactured by NICHIBAN) was attached to the cross-shaped cut and then peeled off.

[0210] Furthermore, a new adhesive tape was attached to the same cross-shaped cut as above, and the tape was peeled off, and the peeling operation was repeated 5 times in total. In each operation, the cured coating film was visually observed to see if it peeled off from the alkali-free glass substrate after peeling off the adhesive tape, and the adhesion was evaluated as follows.

[0211] [Evaluation criteria]

[0212] A: There is no peeling of the cured coating film.

[0213] B: Peeling of the cured coating film occurred after the third time.

[0214] C: Peeling of the cured coating film was observed at the first or second time.

[0215] 2-4. Heat resistance of cured product

[0216] The cured product (cured coating film) of the curable composition obtained in each manufacturing example was prepared in the same manner as in 2-2 (1). Each cured product was placed in a clean oven (manufactured by ESPEC) at 120°C for 500 hours of aging, and the light transmittance after aging was measured according to the steps of 2-2. b* was calculated from the measurement results of the light transmittance spectrum, and the heat resistance was evaluated according to the following evaluation criteria. It should be noted that b* refers to the degree of change in color tone, and the larger the positive value, the stronger the yellow tone.

[0217] [Evaluation criteria]

[0218] A: 0≦b*<1

[0219] B: 1≦b*<2

[0220] C: 2≦b*

[0221] 2-5. Light resistance of cured product

[0222] The cured products (cured coating films) of the curable compositions obtained in the respective manufacturing examples were prepared in the same manner as in 2-2(1) and tested in a sunlight tester (manufactured by ATLAS Material Testing Technology GmbH, CPS+, 765 W / m 2 Each cured product was placed in a 300°C (400°C) room temperature and irradiated with light equivalent to sunlight for 500 hours. The light transmittance after irradiation was measured according to the procedure of 2-2, b* was calculated from the difference in light transmittance before and after irradiation, and the light resistance was evaluated according to the following evaluation criteria. It should be noted that the meaning of b* is the same as that of 2-4.

[0223] [Evaluation criteria]

[0224] A: 0≦b*<1

[0225] B: 1≦b*<2

[0226] C: 2≦b*

[0227] 2-6. Moisture resistance of cured product

[0228] The cured product (cured coating film) of the curable composition obtained in each manufacturing example was prepared in the same manner as in 2-2 (1), and each cured product was placed in a thermostatic chamber at 85° C. and a relative humidity of 85% for 500 hours. After the cured product was taken out and naturally cooled to 25° C., the surface was observed for unevenness using a microscope (magnification 100 times), and the moisture resistance was evaluated according to the following criteria.

[0229] [Evaluation criteria]

[0230] A: No change

[0231] B: Unevenness of the surface of the cured product is partially observed.

[0232] C: The unevenness of the cured product surface can be confirmed visually without observation under a microscope.

[0233] The mixing ratio of the curable composition and the above-mentioned evaluation results are summarized and shown in Table 1. In addition, the ratio of the mass of the monomer (c) having two or more (meth)acrylate groups to the total mass of the polymerizable compound (monomer (c) ratio; mass %) and the ratio of the (meth)acrylate (d) having a cyclic skeleton to the total mass of the polymerizable compound ((meth)acrylate (d) ratio; mass %) in the curable composition of each production example are also shown in Table 1.

[0234] [Table 1]

[0235]

[0236] According to these results, when the curable composition contains a (meth)acrylate (a) having a hydroxyl group and a monomer (c) having two or more (meth)acrylate groups as essential components and does not contain a (meth)acrylate (b) having a phosphate group, if a (meth)acrylate (d) having a cyclic skeleton is further contained, the curing property is excellent, and the transparency, adhesion to the substrate, heat resistance, light resistance, and moisture resistance of the cured product are excellent. In particular, when the ratio of the (meth)acrylate (d2) having a carbocyclic skeleton in the (meth)acrylate (d) having a cyclic skeleton is 50% by mass or more, the heat resistance of the cured product obtained is more excellent (Manufacture Examples 13 to 21).

[0237] In addition, when the curable composition contains a (meth)acrylate (a) having a hydroxyl group, a (meth)acrylate (b) having a phosphate group, and a monomer (c) having two or more (meth)acrylate groups as essential components, if the (meth)acrylate (a) having a hydroxyl group is 10% by mass or more and the (meth)acrylate (b) having a phosphate group is 0.01% by mass or more relative to the total mass of the curable composition, a curable composition in which the cured product has particularly good adhesion to a substrate can be obtained (Manufacture Examples 1 to 8).

[0238] Furthermore, when the ratio of the (meth)acrylate (d) having a cyclic skeleton to the total mass of the polymerizable compound components constituting the curable composition, i.e., the (meth)acrylate (a) having a hydroxyl group, the (meth)acrylate (b) having a phosphate group, the monomer (c) having two or more (meth)acrylate groups, the (meth)acrylate (d) having a cyclic skeleton, and other polymerizable compounds contained as required, is preferably in the range of 30 to 80 mass %, the obtained cured product has the above-mentioned various physical properties such as adhesion to the substrate, heat resistance, light resistance, moisture resistance, etc., which are more balanced and excellent.

[0239] Industrial Applicability

[0240] The curable composition of the present invention has excellent curability, can form a molded product by an inkjet method, and the obtained cured product has excellent properties such as heat resistance, light resistance, moisture resistance and transparency. The curable composition of the present invention is particularly suitable as a composition for LED sealing materials, and is effectively used as a sealing material for micro LED components. In addition, electronic devices using the cured product of the curable composition are effectively used as various display devices, touch panels or lighting; conductive films, organic semiconductor devices, solar cells, organic solar cells, organic photoreceptors (OPC), organic transistors, etc. The optical element using the cured product of the curable composition is effectively used as a component of portable terminals such as liquid crystal backlight devices and smart phones.

[0241] Explanation of symbols

[0242] 1 Micro LED Component

[0243] 2 substrates

[0244] 3 Sealing materials

[0245] 4Joint

[0246] 5. Partition

[0247] 6 Black Layers

[0248] 100 Micro LED Display

Claims

1. A curable composition comprising as essential components a (meth)acrylate having a hydroxyl group (a) and a monomer having two or more (meth)acrylate groups (c).

2. A curable composition comprising the following components (a) to (c) as essential components: (Meth)acrylate (a) having a hydroxyl group, (Meth)acrylate (b) having a phosphoric acid group, - A monomer (c) having two or more (meth)acrylate groups. 3 . The curable composition according to claim 1 , further comprising (meth)acrylate (d) having a cyclic skeleton.

4. The curable composition according to claim 3, wherein The (meth)acrylate (d) having a cyclic skeleton is at least one selected from the group consisting of (meth)acrylate (d1) having a cyclic skeleton containing a heteroatom and (meth)acrylate (d2) having a carbocyclic skeleton.

5. The curable composition according to claim 1 or 2, wherein The monomer (c) having two or more (meth)acrylate groups is contained in an amount of 5 to 50% by mass based on the total mass of the composition.

6. The curable composition according to claim 1 or 2, wherein The monomer (c) having two or more (meth)acrylate groups is a monomer having three or more (meth)acrylate groups.

7. The curable composition according to claim 1 or 2, wherein The (meth)acrylate (a) having a hydroxyl group is contained in an amount of 10 to 50% by mass based on the total mass of the composition.

8. The curable composition according to claim 2, wherein The (meth)acrylate (b) having a phosphoric acid group is contained in an amount of 0.01 to 10% by mass based on the total mass of the composition. 9 . The curable composition according to claim 1 , further comprising a photopolymerization initiator. 10 . The curable composition according to claim 1 , which is an active energy ray-curable composition. 11 . The curable composition according to claim 1 , which has a viscosity of 3 to 30 mPa·s at 25° C. 12 . The curable composition according to claim 1 , which contains no solvent. 13 . The curable composition according to claim 1 or 2 , which is a composition for LED sealing material.

14. The curable composition according to claim 1 or 2, which is molded by an inkjet method.

15. A cured product of the curable composition according to claim 1 or 2. The cured product according to claim 15 , which is an LED sealing material. 17 . An LED element comprising a cured product of the curable composition according to claim 1 .

18. An electronic device using a cured product of the curable composition according to claim 1 or 2.

19. An optical element using a cured product of the curable composition according to claim 1 or 2.

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