Curable resin composition

Abstract

The purpose of the present invention is to provide a curable resin composition having excellent coatability and curability, and excellent light diffusivity after curing. The present invention relates to a curable resin composition containing a polymerizable monomer, the curable resin composition not containing a polymer having 4 or more repeating units, or the content ratio of a polymer having 4 or more repeating units in the curable resin composition being 50 mass% or less. A coating film of the curable resin composition having a thickness of 30 [mu] m before curing has a haze of 1.0% or less as measured in accordance with JIS K 7136, and a cured product of the curable resin composition having a thickness of 30 [mu] m has a haze of 5.0-99.0% as measured in accordance with JIS K 7136.

Description

Technical Field

[0001] The present invention relates to a curable resin composition. Background Art

[0002] Light-emitting diodes (LEDs) are widely used in display devices and the like because of their low power consumption and long lifespan. In recent years, display devices capable of high-quality image display by mounting LED chips using so-called micro LEDs have attracted attention (for example, Patent Document 1 and the like).

[0003] Devices using LEDs have the problem of improving the light extraction efficiency and uniformity. In particular, in the method of converting monochromatic LED light, a layer that diffuses light (light diffusion layer) is required to uniformly guide the light emitted from the light source to the color conversion layer.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2019-212694 Summary of the Invention

[0007] Problems to be Solved by the Invention

[0008] The light diffusion layer is usually formed by applying a curable resin composition using a coating device and then curing it. Therefore, the curable resin composition for the light diffusion layer is required to have excellent coatability, curability, and light diffusibility after curing.

[0009] An object of the present invention is to provide a curable resin composition having excellent coatability and curability, and excellent light diffusibility after curing.

[0010] Means for Solving the Problems

[0011] The present disclosure 1 relates to a curable resin composition containing a polymerizable monomer, the curable resin composition does not contain a polymer having a repeating unit number of 4 or more, or the content ratio of the polymer having a repeating unit number of 4 or more in the above curable resin composition is 50% by mass or less. For a coating film of the above curable resin composition with a thickness of 30 μm before curing, the haze measured according to JIS K 7136 is 1.0% or less, and for a cured product of the above curable resin composition with a thickness of 30 μm, the haze measured according to JIS K 7136 is 5.0% or more and 99.0% or less.

[0012] The present disclosure 2 relates to the curable resin composition of the present disclosure 1, wherein the polymerizable monomer includes an aliphatic monomer and an aromatic monomer that do not have an alicyclic skeleton, and the maximum difference in solubility parameters between the aliphatic monomer that does not have an alicyclic skeleton and the aromatic monomer is 1.5 or more.

[0013] The present disclosure 3 relates to the curable resin composition of the present disclosure 1 or 2, wherein the polymerizable monomer includes an aliphatic monomer and an aromatic monomer that do not have an alicyclic skeleton, and the maximum difference in the dispersion term δD of the Hansen solubility parameter between the aliphatic monomer that does not have an alicyclic skeleton and the aromatic monomer is 1.4 or more.

[0014] The present disclosure 4 relates to the curable resin composition of the present disclosure 1, 2 or 3, wherein the polymerizable monomer includes an aliphatic monomer and an aromatic monomer that do not have an alicyclic skeleton, and the maximum difference in the polar term δP of the Hansen solubility parameter between the aliphatic monomer that does not have an alicyclic skeleton and the aromatic monomer is 1.3 or more.

[0015] The present disclosure 5 relates to the curable resin composition of the present disclosure 1, 2, 3 or 4, wherein the polymerizable monomer includes an aliphatic monomer and an aromatic monomer that do not have an alicyclic skeleton, and the maximum difference in the hydrogen bond term δH of the Hansen solubility parameter between the aliphatic monomer that does not have an alicyclic skeleton and the aromatic monomer is 1.2 or more.

[0016] The present disclosure 6 relates to the curable resin composition of the present disclosure 1, 2, 3, 4 or 5, wherein the polymerizable monomer includes an aliphatic monomer and an aromatic monomer that do not have an alicyclic skeleton, and the maximum difference in refractive index between the aliphatic monomer that does not have an alicyclic skeleton and the aromatic monomer is 0.07 or more.

[0017] The present disclosure 7 relates to the curable resin composition of the present disclosure 2, 3, 4, 5 or 6, wherein the polymerizable monomer further includes an aliphatic monomer having an alicyclic skeleton.

[0018] Hereinafter, the present invention will be described in detail.

[0019] The present inventors studied a curable resin composition containing a polymerizable monomer: on the basis of containing no or almost no oligomer or polymer component, the haze before and after curing was adjusted respectively. As a result, it was found that a curable resin composition excellent in coatability and curability and excellent in light diffusibility after curing could be obtained, and thus the present invention was completed.

[0020] Regarding the curable resin composition of the present invention, the haze measured according to JIS K 7136 (hereinafter, also referred to as "haze before curing") of the coating film of the above curable resin composition with a thickness of 30 μm before curing is 1.0% or less. By making the haze before curing 1.0% or less, the photocurability of the curable resin composition of the present invention becomes excellent. The preferred upper limit of the haze before curing is 0.02%.

[0021] The lower the haze before curing, the more preferred it is, and most preferably it is 0%.

[0022] It should be noted that the haze before curing is measured by the following method.

[0023] That is, first, the curable resin composition is coated on an alkali-free glass substrate with a thickness of 0.7 mm using a spin coater to form a coating film with a thickness of 30 μm, and a test piece is obtained. For the obtained test piece, a haze meter is used to irradiate light with a wavelength of 400 to 700 nm from the side of the coating film of the curable resin composition, and the haze before curing is measured according to JIS K 7136. As the above alkali-free glass substrate, for example, AN10 (manufactured by AGC Inc.) etc. can be used, and as the above haze meter, for example, COH7700 (manufactured by Nippon Denshoku Industries Co., Ltd.) etc. can be used.

[0024] Regarding the curable resin composition of the present invention, the haze measured according to JIS K 7136 (hereinafter, also referred to as "haze after curing") of the cured product of the above curable resin composition with a thickness of 30 μm is 5.0% or more and 99.0% or less. By adjusting the haze after curing to this range, the curable resin composition of the present invention can be suitably used for various purposes.

[0025] It should be noted that the haze after curing is measured by the following method.

[0026] That is, first, the curable resin composition is coated on an alkali-free glass substrate with a thickness of 0.7 mm using a spin coater to form a coating film with a thickness of 30 μm. The obtained coating film is irradiated with ultraviolet light with a wavelength of 365 nm and an illuminance of 100 mW / cm 2 for 30 seconds using a metal halide lamp, and then heated in an oven at 80 °C for 30 minutes to cure the curable resin composition, and a test piece with a cured product having a thickness of 30 μm is obtained. For the obtained test piece, a haze meter is used to irradiate light with a wavelength of 400 to 700 nm from the side of the cured product of the curable resin composition, and the haze after curing is measured according to JIS K 7136. As the above alkali-free glass substrate, for example, AN10 (manufactured by AGC Inc.) etc. can be used, and as the above haze meter, for example, COH7700 (manufactured by Nippon Denshoku Industries Co., Ltd.) etc. can be used.

[0027] The haze before curing and the haze after curing can be set within the above ranges by adjusting the types and contents of the polymerizable monomers and other components contained in the curable resin composition of the present invention.

[0028] The curable resin composition of the present invention contains a polymerizable monomer. The above polymerizable monomer refers to a monomer having a polymerizable group.

[0029] Examples of the above polymerizable group include a cationic polymerizable group, a radical polymerizable group, etc. Among them, a cationic polymerizable group is preferred, and an epoxy group and an oxetanyl group are more preferred.

[0030] The above polymerizable monomer preferably includes an aliphatic monomer and an aromatic monomer that do not have an alicyclic skeleton. By including the above aliphatic monomer and the above aromatic monomer that do not have an alicyclic skeleton, the curable resin composition of the present invention can easily adjust the haze before curing, the haze after curing, and the viscosity described below. In particular, by forming a phase separation structure when the above aliphatic monomer and the above aromatic monomer that do not have an alicyclic skeleton are polymerized by light irradiation, it is easier to make the haze after curing within the above range.

[0031] The maximum difference in solubility parameters (hereinafter, also referred to as "the maximum difference in SP value") between the above aliphatic monomer and the above aromatic monomer that do not have an alicyclic skeleton is preferably 1.5 or more. By making the maximum difference in SP value 1.5 or more, the above aliphatic monomer and the above aromatic monomer that do not have an alicyclic skeleton easily form a phase separation structure when polymerized by light irradiation. Therefore, it is easier to make the haze after curing within the above range. A more preferred lower limit of the maximum difference in SP value is 1.9.

[0032] The preferred upper limit of the maximum difference in SP value is not particularly limited, and the substantial upper limit is 10.0.

[0033] It should be noted that in this specification, the above solubility parameter (SP value) is the Hansen solubility parameter, which can be derived by calculation according to the structural formula using HSP software. As the above HSP software, Hansen Solubility Parameter in Practice (HSPiP) can be used. In addition, the maximum difference of the above SP values refers to: when the absolute value difference between the SP value of the aliphatic monomer without an alicyclic skeleton having the largest SP value among the above aliphatic monomers without an alicyclic skeleton and the SP value of the aromatic monomer having the smallest SP value among the above aromatic monomers is set as a, and the absolute value difference between the SP value of the aliphatic monomer without an alicyclic skeleton having the smallest SP value among the above aliphatic monomers without an alicyclic skeleton and the SP value of the aromatic monomer having the largest SP value among the above aromatic monomers is set as b, the larger value of a and b.

[0034] The maximum difference in the dispersion term δD of the Hansen solubility parameters of the above aliphatic monomer without an alicyclic skeleton and the above aromatic monomer (hereinafter, also referred to as "the maximum difference in δD") is preferably 1.4 or more. By making the maximum difference in δD 1.4 or more, the above aliphatic monomer without an alicyclic skeleton and the above aromatic monomer are likely to form a phase separation structure during polymerization by light irradiation. Therefore, it is easier to make the haze of the above cured product within the above range. A more preferable lower limit of the maximum difference in δD is 3.2.

[0035] There is no particular limitation on the preferable upper limit of the maximum difference in δD, and the substantial upper limit is 5.0.

[0036] It should be noted that the above δD can be derived by calculation according to the structural formula using the above HSP software. In addition, the maximum difference in δD refers to: when the absolute value difference between the δD of the aliphatic monomer without an alicyclic skeleton having the largest δD among the above aliphatic monomers without an alicyclic skeleton and the δD of the aromatic monomer having the smallest δD among the above aromatic monomers is set as c, and the absolute value difference between the δD of the aliphatic monomer without an alicyclic skeleton having the smallest δD among the above aliphatic monomers without an alicyclic skeleton and the δD of the aromatic monomer having the largest δD among the above aromatic monomers is set as d, the larger value of c and d.

[0037] The maximum difference in the polar term δP of the Hansen solubility parameters of the above aliphatic monomer without an alicyclic skeleton and the above aromatic monomer (hereinafter, also referred to as "the maximum difference in δP") is preferably 1.3 or more. By making the maximum difference in δP 1.3 or more, the above aliphatic monomer without an alicyclic skeleton and the above aromatic monomer are likely to form a phase separation structure during polymerization by light irradiation. Therefore, it is easier to make the haze of the above cured product within the above range. A more preferable lower limit of the maximum difference in δP is 1.5.

[0038] The preferred upper limit of the maximum difference of the above δP is not particularly limited, and the substantial upper limit is 5.0.

[0039] It should be noted that the above δP can be derived by calculation according to the structural formula using the above HSP software. In addition, the maximum difference of the above δP means: when the absolute value difference between the δP of the aliphatic monomer without an alicyclic skeleton having the largest δP among the above aliphatic monomers without an alicyclic skeleton and the δP of the aromatic monomer having the smallest δP among the above aromatic monomers is set as e, and the absolute value difference between the δP of the aliphatic monomer without an alicyclic skeleton having the smallest δP among the above aliphatic monomers without an alicyclic skeleton and the δP of the aromatic monomer having the largest δP among the above aromatic monomers is set as f, the larger value of e and f.

[0040] The maximum difference in the hydrogen bond term δH of the Hansen solubility parameters of the above aliphatic monomer without an alicyclic skeleton and the above aromatic monomer (hereinafter, also referred to as "the maximum difference in δH") is preferably 1.2 or more. By making the maximum difference in δH 1.2 or more, the above aliphatic monomer without an alicyclic skeleton and the above aromatic monomer are likely to form a phase-separated structure during polymerization by light irradiation. Therefore, it is easier to make the haze of the above cured product within the above range. The more preferred lower limit of the maximum difference in δH is 1.6.

[0041] The preferred upper limit of the maximum difference in δH is not particularly limited, and the substantial upper limit is 5.0.

[0042] It should be noted that the above δH can be derived by calculation according to the structural formula using the above HSP software. In addition, the maximum difference in δH means: when the absolute value difference between the δH of the aliphatic monomer without an alicyclic skeleton having the largest δH among the above aliphatic monomers without an alicyclic skeleton and the δH of the aromatic monomer having the smallest δH among the above aromatic monomers is set as g, and the absolute value difference between the δH of the aliphatic monomer without an alicyclic skeleton having the smallest δH among the above aliphatic monomers without an alicyclic skeleton and the δH of the aromatic monomer having the largest δH among the above aromatic monomers is set as h, the larger value of g and h.

[0043] The maximum difference in the refractive index of the above aliphatic monomer without an alicyclic skeleton and the above aromatic monomer (hereinafter, also referred to as "the maximum difference in refractive index") is preferably 0.07 or more. By making the maximum difference in refractive index 0.07 or more, it is easier to make the haze of the above cured product within the above range. The more preferred lower limit of the maximum difference in refractive index is 0.14.

[0044] The preferred upper limit of the maximum difference in refractive index is not particularly limited, and the substantial upper limit is 0.30.

[0045] It should be noted that in this specification, the above refractive index refers to the refractive index for the sodium D line measured using an Abbe refractometer at 25°C. As the above Abbe refractometer, for example, a general Abbe refractometer ER-7MW (manufactured by ERMA Inc.) etc. can be used. Additionally, the maximum difference in the above refractive index means: when the absolute value difference between the refractive index of the aliphatic monomer without an alicyclic skeleton having the maximum refractive index among the aliphatic monomers without an alicyclic skeleton and the refractive index of the aromatic monomer having the minimum refractive index among the aromatic monomers is set as i, and the absolute value difference between the refractive index of the aliphatic monomer without an alicyclic skeleton having the minimum refractive index among the aliphatic monomers without an alicyclic skeleton and the refractive index of the aromatic monomer having the maximum refractive index among the aromatic monomers is set as j, the larger value of this i and this j.

[0046] As the above aliphatic monomer without an alicyclic skeleton, for example, an aliphatic epoxy compound without an alicyclic skeleton, an aliphatic oxetane compound without an alicyclic skeleton, etc. can be cited.

[0047] As the above aliphatic epoxy compound without an alicyclic skeleton, for example, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, trimethylolpropane triglycidyl ether, etc. can be cited.

[0048] As the above aliphatic oxetane compound without an alicyclic skeleton, for example, 3-ethyl-3-((2-ethylhexyloxy)methyl)oxetane, 3-ethyl-3-(4-hydroxybutoxymethyl)oxetane, 3-ethyl-3-hydroxymethyloxetane, 3-ethyl-3-(((3-ethyloxetan-3-yl)methoxy)methyl)oxetane, 3-ethyl-3-((3-(triethoxysilyl)propoxy)methyl)oxetane, etc. can be cited.

[0049] The preferable lower limit of the content of the above aliphatic monomer without an alicyclic skeleton in 100 parts by mass of the above polymerizable monomer is 10 parts by mass, and the preferable upper limit is 90 parts by mass. By making the content of the above aliphatic monomer without an alicyclic skeleton within this range, it becomes easier to make the haze of the above cured product within the above range. The more preferable lower limit of the content of the above aliphatic monomer without an alicyclic skeleton is 30 parts by mass, and the more preferable upper limit is 70 parts by mass.

[0050] As the above aromatic monomer, for example, an aromatic epoxy compound, an aromatic oxetane compound, etc. can be cited.

[0051] Examples of the above aromatic epoxy compounds include 4-tert-butylphenyl glycidyl ether, o-phenylphenol glycidyl ether, bisphenol A type epoxy compound, bisphenol F type epoxy compound, bisphenol E type epoxy compound, etc.

[0052] Examples of the above aromatic oxetane compounds include phenoxymethyl oxetane, 3-ethyl-3-(phenoxymethyl)oxetane, 1,4-bis(((3-ethyl-3-oxetanyl)methoxy)methyl)benzene, 4,4-bis((3-ethyl-3-oxetanyl)methoxymethyl)biphenyl, bis((3-ethyl-3-oxetanylmethyl) isophthalate), etc.

[0053] The preferred lower limit of the content of the above aromatic monomer in 100 parts by mass of the above polymerizable monomer is 10 parts by mass, and the preferred upper limit is 90 parts by mass. By making the content of the above aromatic monomer within this range, it becomes easier to make the haze of the above cured product within the above range. The more preferred lower limit of the content of the above aromatic monomer is 30 parts by mass, and the more preferred upper limit is 70 parts by mass.

[0054] The above polymerizable monomer preferably further contains an aliphatic monomer having an alicyclic skeleton. By containing the above aliphatic monomer having an alicyclic skeleton, the curability of the resulting curable resin composition becomes more excellent. In addition, by containing the above aliphatic monomer having an alicyclic skeleton, phase separation of the polymerizable monomer in the curable resin composition before curing is less likely to occur, and thus the storage stability of the resulting curable resin composition becomes excellent.

[0055] It should be noted that a polymerizable monomer having an alicyclic skeleton and an aromatic ring is treated as the above aromatic monomer.

[0056] Examples of the above aliphatic monomer having an alicyclic skeleton include an aliphatic epoxy compound having an alicyclic skeleton, an aliphatic oxetane compound having an alicyclic skeleton, etc.

[0057] Examples of the above aliphatic epoxy compound having an alicyclic skeleton include an alicyclic epoxy modified silicone compound, a dicyclopentadiene type epoxy compound, 3,4-epoxycyclohexylmethyl (3,4-epoxy)cyclohexanecarboxylate, 4,4'-bis(1,2-epoxycyclohexane), etc.

[0058] Examples of the above aliphatic oxetane compound having an alicyclic skeleton include 3-(cyclohexyloxy)methyl-3-ethyloxetane, 2-cyclohexyloxetan-3-one, etc.

[0059] The preferred lower limit of the content of the aliphatic monomer having an alicyclic skeleton in 100 parts by mass of the above-mentioned polymerizable monomer is 3 parts by mass, and the preferred upper limit is 40 parts by mass. By making the content of the aliphatic monomer having an alicyclic skeleton within this range, the curability and light diffusibility after curing of the resulting curable resin composition become more excellent. The more preferred lower limit of the content of the aliphatic monomer having an alicyclic skeleton is 5 parts by mass, and the more preferred upper limit is 30 parts by mass.

[0060] The preferred lower limit of the content ratio of the above-mentioned polymerizable monomer in the curable resin composition of the present invention is 60% by mass, and the preferred upper limit is 95% by mass. By making the content ratio of the above-mentioned polymerizable monomer within this range, the coatability, curability, and light diffusibility after curing of the resulting curable resin composition become more excellent. The more preferred lower limit of the content ratio of the above-mentioned polymerizable monomer is 70% by mass, and the more preferred upper limit is 80% by mass.

[0061] The curable resin composition of the present invention preferably further contains a photoinitiator.

[0062] Examples of the above-mentioned photoinitiator include a photo cationic polymerization initiator, a photo radical polymerization initiator, etc. Among them, it is preferable to use the above-mentioned photo cationic polymerization initiator in combination with a polymerizable monomer having a cationic polymerizable group as the above-mentioned polymerizable monomer.

[0063] The above-mentioned photo cationic polymerization initiator is not particularly limited as long as it generates a protonic acid or a Lewis acid by light irradiation, and it can be an ionic photoacid generator type or a non-ionic photoacid generator type.

[0064] As the anion part of the above-mentioned ionic photoacid generator type photo cationic polymerization initiator, for example, BF4 - , PF6 - , SbF6 - , (BX4) - (wherein, X represents a phenyl group substituted with at least 2 or more fluorine or trifluoromethyl groups), etc. In addition, as the above-mentioned anion part, PF m (C n F 2n＋1 ) 6-m - (wherein, in the formula, m is an integer of 0 or more and 5 or less, and n is an integer of 1 or more and 6 or less), etc.

[0065] Examples of the above-mentioned ionic photoacid generator type photo cationic polymerization initiator include: aromatic sulfonium salts, aromatic iodonium salts, aromatic diazonium salts, aromatic ammonium salts, (2,4-cyclopentadien-1-yl)((1-methylethyl)benzene)-Fe salts, etc. having the above-mentioned anion part.

[0066] Examples of the above-mentioned aromatic sulfonium salts include: bis(4-(diphenylsulfonium)phenyl)sulfide bis(hexafluorophosphate), bis(4-(diphenylsulfonium)phenyl)sulfide bis(hexafluoroantimonate), bis(4-(diphenylsulfonium)phenyl)sulfide bis(tetrafluoroborate), bis(4-(diphenylsulfonium)phenyl)sulfide tetrakis(pentafluorophenyl)borate, diphenyl-4-(phenylthio)phenylsulfonium hexafluorophosphate, diphenyl-4-(phenylthio)phenylsulfonium hexafluoroantimonate, diphenyl-4-(phenylthio)phenylsulfonium tetrafluoroborate, diphenyl-4-(phenylthio)phenylsulfonium tetrakis(pentafluorophenyl)borate, triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium tetrafluoroborate, triphenylsulfonium tetrakis(pentafluorophenyl)borate, bis(4-(bis(4-(2-hydroxyethoxy))phenylsulfonium)phenyl)sulfide bis(hexafluorophosphate), bis(4-(bis(4-(2-hydroxyethoxy))phenylsulfonium)phenyl)sulfide bis(hexafluoroantimonate), bis(4-(bis(4-(2-hydroxyethoxy))phenylsulfonium)phenyl)sulfide bis(tetrafluoroborate), bis(4-(bis(4-(2-hydroxyethoxy))phenylsulfonium)phenyl)sulfide tetrakis(pentafluorophenyl)borate, tris(4-(4-acetylphenyl)phenylthio)sulfonium tetrakis(pentafluorophenyl)borate, and the like.

[0067] Examples of the above-mentioned aromatic iodonium salts include: diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate, diphenyliodonium tetrafluoroborate, diphenyliodonium tetrakis(pentafluorophenyl)borate, bis(dodecylphenyl)iodonium hexafluorophosphate, bis(dodecylphenyl)iodonium hexafluoroantimonate, bis(dodecylphenyl)iodonium tetrafluoroborate, bis(dodecylphenyl)iodonium tetrakis(pentafluorophenyl)borate, 4-methylphenyl-4-(1-methylethyl)phenyl iodonium hexafluorophosphate, 4-methylphenyl-4-(1-methylethyl)phenyl iodonium hexafluoroantimonate, 4-methylphenyl-4-(1-methylethyl)phenyl iodonium tetrafluoroborate, 4-methylphenyl-4-(1-methylethyl)phenyl iodonium tetrakis(pentafluorophenyl)borate, and the like.

[0068] Examples of the above-mentioned aromatic diazonium salts include: phenyl diazonium hexafluorophosphate, phenyl diazonium hexafluoroantimonate, phenyl diazonium tetrafluoroborate, phenyl diazonium tetrakis(pentafluorophenyl)borate, and the like.

[0069] As the above-mentioned aromatic ammonium salts, for example, the following can be cited: 1-benzyl-2-cyanopyridinium hexafluorophosphate, 1-benzyl-2-cyanopyridinium hexafluoroantimonate, 1-benzyl-2-cyanopyridinium tetrafluoroborate, 1-benzyl-2-cyanopyridinium tetrakis(pentafluorophenyl)borate, 1-(naphthylmethyl)-2-cyanopyridinium hexafluorophosphate, 1-(naphthylmethyl)-2-cyanopyridinium hexafluoroantimonate, 1-(naphthylmethyl)-2-cyanopyridinium tetrafluoroborate, 1-(naphthylmethyl)-2-cyanopyridinium tetrakis(pentafluorophenyl)borate, etc.

[0070] As the above-mentioned (2,4-cyclopentadien-1-yl)((1-methylethyl)benzene)-Fe salts, for example, the following can be cited: (2,4-cyclopentadien-1-yl)((1-methylethyl)benzene)-Fe(II) hexafluorophosphate, (2,4-cyclopentadien-1-yl)((1-methylethyl)benzene)-Fe(II) hexafluoroantimonate, (2,4-cyclopentadien-1-yl)((1-methylethyl)benzene)-Fe(II) tetrafluoroborate, (2,4-cyclopentadien-1-yl)((1-methylethyl)benzene)-Fe(II) tetrakis(pentafluorophenyl)borate, etc.

[0071] As the above-mentioned nonionic photoacid-generating photo cationic polymerization initiators, for example, the following can be cited: nitrobenzyl esters, sulfonic acid derivatives, phosphoric acid esters, phenol sulfonic acid esters, diazonaphthoquinones, N-hydroxyimide sulfonic acid esters, etc.

[0072] As commercially available products among the above-mentioned photo cationic polymerization initiators, for example, the following can be cited: photo cationic polymerization initiators manufactured by Midori Kagaku Co., Ltd., photo cationic polymerization initiators manufactured by Union Carbide Corporation, photo cationic polymerization initiators manufactured by ADEKA Corporation, photo cationic polymerization initiators manufactured by 3M Company, photo cationic polymerization initiators manufactured by BASF Company, photo cationic polymerization initiators manufactured by Rhodia Company, photo cationic polymerization initiators manufactured by San-Apro Company, etc.

[0073] As the above-mentioned photo cationic polymerization initiators manufactured by Midori Kagaku Co., Ltd., for example, DTS-200, etc. can be cited.

[0074] As the above-mentioned photo cationic polymerization initiators manufactured by Union Carbide Corporation, for example, UVI6990, UVI6974, etc. can be cited.

[0075] As the above-mentioned photo cationic polymerization initiators manufactured by ADEKA Corporation, for example, SP-150, SP-170, etc. can be cited.

[0076] As the above-mentioned photo cationic polymerization initiators manufactured by 3M Company, for example, FC-508, FC-512, etc. can be cited.

[0077] Examples of the photo cationic polymerization initiator manufactured by BASF Corporation as described above include IRGACURE 261, IRGACURE 290, and the like.

[0078] Examples of the photo cationic polymerization initiator manufactured by Rhodia Corporation as described above include PI 2074 and the like.

[0079] Examples of the photo cationic polymerization initiator manufactured by San-Apro Corporation as described above include CPI-100P, CPI-200K, CPI-210S, CPI-410S, and the like.

[0080] With respect to 100 parts by mass of the above-mentioned polymerizable monomer, the preferable lower limit of the content of the above-mentioned photoinitiator is 0.01 part by mass, and the preferable upper limit is 10 parts by mass. By making the content of the above-mentioned photoinitiator 0.01 part by mass or more, the photocurability of the obtained curable resin composition becomes more excellent. By making the content of the above-mentioned photoinitiator 10 parts by mass or less, the curing reaction of the obtained curable resin composition does not become too fast, the workability becomes more excellent, and the cured product can be made more uniform. The more preferable lower limit of the content of the above-mentioned photoinitiator is 0.05 part by mass, and the more preferable upper limit is 5 parts by mass.

[0081] The curable resin composition of the present invention does not contain a polymer having a repeating unit number of 4 or more, or the content ratio of the polymer having a repeating unit number of 4 or more in the above-mentioned curable resin composition is 50% by mass or less. Hereinafter, the polymer having a repeating unit number of 4 or more will also be referred to as an "oligomer or polymer component". When the above-mentioned oligomer or polymer component is contained, a phase separation structure is likely to be formed after curing, and the obtained cured product is likely to be a cured product having excellent light diffusibility, but the viscosity becomes too high and the coatability deteriorates. By making the curable resin composition of the present invention not contain the above-mentioned oligomer or polymer component, or the content ratio of the above-mentioned oligomer or polymer component is 50% by mass or less, the excellent light diffusibility after curing is maintained, and the coatability also becomes excellent. The content ratio of the above-mentioned oligomer or polymer component is more preferably 10% by mass or less, further preferably 5% by mass or less, and particularly preferably 1% by mass or less. The curable resin composition of the present invention most preferably does not contain the above-mentioned oligomer or polymer component.

[0082] The curable resin composition of the present invention preferably does not contain a filler, or the content ratio of the filler in the above curable resin composition is 20% by mass or less. By making the curable resin composition of the present invention not contain the above filler, or the content ratio of the above filler is 20% by mass or less, the coatability of the obtained curable resin composition becomes more excellent, and it is easier to adjust the haze before curing to the above range. The content ratio of the above filler is more preferably 5% by mass or less, further preferably 1% by mass or less, and particularly preferably 0.1% by mass or less. The curable resin composition of the present invention most preferably does not contain the above filler.

[0083] The curable resin composition of the present invention may contain various known additives such as a leveling agent, a sensitizer, a thermal curing agent, a silane coupling agent, a plasticizer, a curing retarder, an ultraviolet absorber, an antioxidant, a flame retardant, an antistatic agent, and an antifoaming agent as needed within a range not hindering the object of the present invention.

[0084] As a method for producing the curable resin composition of the present invention, for example, there can be mentioned a method of uniformly mixing a polymerizable monomer, a photoinitiator, and a leveling agent added as needed using a stirrer.

[0085] The preferred lower limit of the viscosity of the curable resin composition of the present invention at 25°C is 5.0 mPa·s, and the preferred upper limit is 100.0 mPa·s. By making the viscosity at 25°C within this range, the coatability of the curable resin composition of the present invention based on an inkjet method or the like becomes more excellent. The more preferred lower limit of the viscosity at 25°C is 10.0 mPa·s, and the more preferred upper limit is 50.0 mPa·s.

[0086] It should be noted that the above viscosity can be measured, for example, using a VISCOMETER TV-22 (manufactured by Toki Sangyo Co., Ltd.) as an E-type viscometer and a No. 1 rotor at a rotation speed of 100 rpm.

[0087] The curable resin composition of the present invention can be cured by light irradiation.

[0088] As a method for curing the curable resin composition of the present invention by light irradiation, for example, there can be mentioned a method of irradiating light having a wavelength of 300 nm or more and 400 nm or less and a cumulative light amount of 300 mJ / cm 2 or more and 3000 mJ / cm 2 or less.

[0089] Examples of the light source for irradiating the curable resin composition of the present invention include low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, excimer lasers, chemical lamps, black lights, microwave-excited mercury lamps, metal halide lamps, sodium lamps, halogen lamps, xenon lamps, LED lamps, fluorescent lamps, sunlight, electron beam irradiation devices, etc. These light sources can be used alone or in combination of two or more kinds.

[0090] Examples of the method for irradiating the curable resin composition of the present invention include simultaneous irradiation with various light sources, sequential irradiation with a time difference, combined irradiation of simultaneous irradiation and sequential irradiation, etc., and any irradiation method can be used.

[0091] Advantages of the Invention

[0092] According to the present invention, a curable resin composition excellent in coatability and curability and excellent in light diffusibility after curing can be provided. Detailed Description of Embodiments

[0093] Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

[0094] (Examples 1 to 18, Comparative Examples 1 to 7)

[0095] Curable resin compositions of Examples 1 to 18 and Comparative Examples 1 to 7 were prepared by stirring and mixing the respective materials using a stirrer according to the mixing ratios shown in Tables 1 to 3. As the above stirrer, Awatori Rentaro ARE-310 (manufactured by THINKY Corporation) was used.

[0096] It should be noted that "Actflow BE2" used in Comparative Example 7 is a polymer having a repeating unit number of 4 or more.

[0097] (Maximum difference in SP value, maximum difference in δD, maximum difference in δP, and maximum difference in δH)

[0098] The SP values, δD, δP, and δH derived from the HSPiP of each polymerizable monomer used in the Examples and Comparative Examples, and the maximum difference in the SP value, the maximum difference in δD, the maximum difference in δP, and the maximum difference in δH calculated from these values are shown in Tables 1 to 3.

[0099] (Maximum difference in refractive index)

[0100] For each polymerizable monomer used in the Examples and Comparative Examples, the refractive index for the sodium D line was measured at 25 °C using an Abbe refractometer (manufactured by ERMA, "General Abbe Refractometer ER-7MW"). The results are shown in Tables 1 to 3. In addition, the maximum difference in refractive index calculated from the obtained refractive index values is shown in Tables 1 to 3.

[0101] (Haze before curing)

[0102] Each obtained curable resin composition was applied onto an alkali-free glass substrate (manufactured by AGC Inc., "AN10") with a thickness of 0.7 mm using a spin coater, thereby forming a coating film with a thickness of 30 μm, and test pieces were obtained. For the obtained test pieces, using a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., "COH7700"), light with a wavelength of 400 to 700 nm was irradiated from the side of the coating film of the curable resin composition, and the haze before curing was measured in accordance with JIS K 7136. The results are shown in Tables 1 to 3.

[0103] (Haze after curing)

[0104] Each obtained curable resin composition was applied onto an alkali-free glass substrate (manufactured by AGC Inc., "AN10") with a thickness of 0.7 mm using a spin coater, thereby forming a coating film with a thickness of 30 μm. The obtained coating film was irradiated with ultraviolet light having a wavelength of 365 nm and an illuminance of 100 mW / cm 2 for 30 seconds using a metal halide lamp, and then heated in an oven at 80°C for 30 minutes to cure the curable resin composition, obtaining test pieces having a cured product with a thickness of 30 μm. For the obtained test pieces, using a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., "COH7700"), light with a wavelength of 400 to 700 nm was irradiated from the side of the cured product of the curable resin composition, and the haze after curing was measured in accordance with JIS K 7136. The results are shown in Tables 1 to 3.

[0105] <Evaluation>

[0106] Each curable resin composition obtained in the examples and comparative examples was evaluated by the following method. The results are shown in Tables 1 to 3.

[0107] (Viscosity)

[0108] For each obtained curable resin composition, the viscosity was measured using an E-type viscometer (manufactured by Toki Sangyo Co., Ltd., "VISCOMETER TV-22") and a No. 1 rotor under the conditions of 25°C and a rotation speed of 100 rpm.

[0109] (Curability)

[0110] When the haze measured in the above "(Haze before curing)" was 1.0 or less, it was denoted as "A", and when it exceeded 1.0, it was denoted as "B", and the curability was evaluated.

[0111] (Light diffusibility after curing)

[0112] The haze measured in the above “(haze after curing)” of 5.0% or more and 99.0% or less was designated as “A”, and the case of less than 5.0% or more than 99.0% was designated as “B”, and the light diffusibility after curing was evaluated.

[0113] (Storage stability)

[0114] For each of the obtained curable resin compositions, after production, it was stored for 24 hours in an environment of 25 °C and 50% RH. The curable resin composition after storage was visually observed, and the case where phase separation was not confirmed was designated as “A”, and the case where phase separation was confirmed was designated as “B”, and the storage stability was evaluated.

[0115] [Table 1]

[0116]

[0117] [Table 2]

[0118]

[0119] [Table 3]

[0120]

[0121] As shown in Tables 1 to 3 above, the curable resin compositions obtained in Examples 1 to 18 had adaptability to inkjet coating. On the other hand, the curable resin composition obtained in Comparative Example 7 had extremely high viscosity at 25 °C, so it did not have adaptability to inkjet coating and could not be coated by the inkjet method.

[0122] Industrial availability

[0123] According to the present invention, a curable resin composition excellent in coatability and curability and excellent in light diffusibility after curing can be provided.

Claims

1. A curable resin composition, characterized in that, It contains polymerizable monomers. The curable resin composition does not contain polymers having 4 or more repeating units, or the content ratio of polymers having 4 or more repeating units in the curable resin composition is 50% by mass or less. For the coating film of the curable resin composition with a thickness of 30 μm before curing, the haze measured according to JIS K 7136 is 1.0% or less, and for the cured product of the curable resin composition with a thickness of 30 μm, the haze measured according to JIS K 7136 is 5.0% or more and 99.0% or less.

2. The curable resin composition according to claim 1, wherein, The polymerizable monomers include aliphatic monomers and aromatic monomers without an alicyclic skeleton, and the maximum difference in solubility parameters between the aliphatic monomers without an alicyclic skeleton and the aromatic monomers is 1.5 or more.

3. The curable resin composition according to claim 1 or 2, wherein The polymerizable monomers include aliphatic monomers and aromatic monomers without an alicyclic skeleton, and the maximum difference in the dispersion term δD of the Hansen solubility parameters between the aliphatic monomers without an alicyclic skeleton and the aromatic monomers is 1.4 or more.

4. The curable resin composition according to claim 1, 2 or 3, wherein, The polymerizable monomers include aliphatic monomers and aromatic monomers without an alicyclic skeleton, and the maximum difference in the polar term δP of the Hansen solubility parameters between the aliphatic monomers without an alicyclic skeleton and the aromatic monomers is 1.3 or more.

5. The curable resin composition according to claim 1, 2, 3 or 4, wherein, The polymerizable monomers include aliphatic monomers and aromatic monomers without an alicyclic skeleton, and the maximum difference in the hydrogen bond term δH of the Hansen solubility parameters between the aliphatic monomers without an alicyclic skeleton and the aromatic monomers is 1.2 or more.

6. The curable resin composition according to claim 1, 2, 3, 4 or 5, wherein, The polymerizable monomers include aliphatic monomers and aromatic monomers without an alicyclic skeleton, and the maximum difference in refractive index between the aliphatic monomers without an alicyclic skeleton and the aromatic monomers is 0.07 or more.

7. The curable resin composition according to claim 2, 3, 4, 5 or 6, wherein, The polymerizable monomers further include aliphatic monomers having an alicyclic skeleton.

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