Container-packaged photocurable resin composition

Abstract

The present invention provides a containerized photocurable resin composition in which thickening of the photocurable resin composition is suppressed and storage stability is good. [Solution] A containerized photocurable resin composition, which is filled in a container, The aforementioned photocurable resin composition comprises a polyfunctional photopolymerizable compound having a viscosity of 1,000 mPa·s or less at 25°C, and a photopolymerization initiator, and the content of the organic solvent is 1% by mass or less. A photocurable resin composition in a container, wherein the volume filling rate of the photocurable resin composition relative to the capacity of the filling container is 90 vol% or less.

Description

Technical Field

[0001] The present invention relates to a photocurable resin composition in a container.

Background Art

[0002] By applying a photocurable resin composition to a substrate such as a printed wiring board and photocuring it, it is widely used as a resist coating film such as a solder resist. In such a resin composition, when it contains an organic solvent, there are drawbacks such as the need for a solvent drying process after application to the substrate, the possibility of dripping of the liquid after application, and a large environmental load. Therefore, in recent years, solventless photocurable thermosetting resin compositions have come to be used as resist inks (Patent Documents 1 to 3).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the case of a solventless photocurable resin composition, even when stored in a container under light shielding, the photocurable resin composition as the content may thicken.

[0005] In view of the above problems, an object of the present invention is to provide a photocurable resin composition in a container in which thickening of the photocurable resin composition is suppressed, storage stability is good, and coating film physical properties of the photocurable resin composition are also good.

Means for Solving the Problems

[0006] To solve the above problems, the inventors conducted extensive research and found that by filling a photocurable resin composition containing a polyfunctional photopolymerizable compound with a viscosity of 1,000 mPa·s or less at 25°C and a photopolymerization initiator, and having an organic solvent content of 1% by mass or less, into a container such that the volume filling rate of the photocurable resin composition relative to the capacity of the container is 90 vol% or less, the thickening of the photocurable resin composition is suppressed and storage stability is improved.

[0007] This invention was completed based on these findings and includes the following broad embodiments of the invention. [Section 1] A containerized photocurable resin composition, which is filled in a container, The aforementioned photocurable resin composition comprises a polyfunctional photopolymerizable compound having a viscosity of 1,000 mPa·s or less at 25°C, a photopolymerization initiator, and an organic solvent content of 1% by mass or less. A photocurable resin composition in a container, wherein the volume filling rate of the photocurable resin composition relative to the capacity of the filling container is 90 vol% or less. [Section 2] The containerized photocurable resin composition according to item 1, wherein the material of the filling container is a polyolefin resin. [Section 3] The containerized photocurable resin composition according to item 2, wherein the polyolefin resin is polyethylene or polypropylene. [Section 4] The photocurable resin composition in a container according to any one of claims 1 to 3, further comprising a photopolymerizable compound having a viscosity of 1,500 mPa·s or more at 25°C. [Section 5] The photocurable resin composition in a container according to any one of claims 1 to 4, wherein the photocurable resin composition further contains an inorganic filler. [Section 6] The photocurable resin composition in a container according to any one of claims 1 to 5, wherein the photocurable resin composition further contains a radical polymerization inhibitor. [Section 7] The photocurable resin composition in a container according to any one of claims 1 to 6, wherein the viscosity of the photocurable resin composition at 25°C is 300 dPa·s or less. [Section 8] The containerized photocurable resin composition according to any one of claims 1 to 6, wherein the filling container is a light-shielding container. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a photocurable resin composition in a container that has suppressed thickening, good storage stability, and good coating film properties. [Modes for carrying out the invention]

[0009] In this specification, (meth)acrylate means at least one selected from the group consisting of acrylate (acrylic acid ester) and methacrylate (methacrylic acid ester). Furthermore, when a numerical range is expressed using "~" such as "A~B", unless otherwise specified, this means "A or greater and B or less".

[0010] The present invention provides a containerized photocurable resin composition. The containerized photocurable resin composition of the present invention has a volume filling ratio of 90 vol% or less of the photocurable resin composition relative to the capacity of the filling container. Furthermore, the photocurable resin composition contains a polyfunctional photopolymerizable compound having a viscosity of 1,000 mPa·s or less at 25°C and a photopolymerization initiator, and has an organic solvent content of 1% by mass or less.

[0011] The volumetric filling ratio of the photocurable resin composition relative to the capacity of the filling container is 90 vol% or less, preferably 87 vol% or less, and more preferably 85 vol% or less. A volumetric filling ratio exceeding 90 vol% is undesirable because it tends to thicken the photocurable resin composition, reducing its storage stability. The "volumetric filling ratio" is a value calculated from the capacity of the plastic container and the volume of the resin composition at 10 to 30°C (especially 22°C).

[0012] When the volume filling rate exceeds 90 vol%, the following mechanisms, but not limited thereto, are presumed to be the reasons why the photocurable resin composition tends to thicken.

[0013] When the volume filling rate with respect to the capacity of the filling container exceeds 90 vol%, the amount of air in the filling container is in a low state. Therefore, the amount of oxygen supplied to the photocurable resin composition in the filling container decreases, the inhibition of radical reaction by oxygen is reduced, and the polymerization of the photopolymerizable compound proceeds, so it is presumed that the photocurable resin composition thickens. Here, when the photocurable resin composition contains an organic solvent, it is considered that the thickening is suppressed because the organic solvent acts as a chain transfer agent. However, in the photocurable resin composition of the present invention, since the content of the organic solvent is very small at 1 mass% or less, such an effect cannot be expected. Further, in the photocurable resin composition of the present invention, since a polyfunctional photopolymerizable compound is included as an essential component, the influence on thickening due to polymerization is large. Therefore, it is presumed that it is important to set the volume filling rate with respect to the capacity of the filling container to 90 vol% or less.

[0014] In one embodiment, the thickening rate of the photocurable resin composition in the photocurable resin composition contained in a container after storage at 50 °C for 7 days is preferably 50% or less, more preferably 40% or less, still more preferably 30% or less, particularly preferably 20% or less, and most preferably 15% or less. When it is within the above range, the storage stability is good. The "thickening rate" is the viscosity at the initial stage of preparation of the photocurable resin composition (initial viscosity), filled in a filling container, stored in a constant temperature bath at 50 °C for 7 days, and then returned to 25 °C, and the viscosity after storage at 50 °C (viscosity after storage at 50 °C) is measured and calculated according to the following formula. Thickening rate (%) = {(viscosity after storage at 50 °C - initial viscosity) / (initial viscosity)} × 100 Further, the "viscosity" conforms to "10 Cone - Method for measuring viscosity by plate - type rotational viscometer" of JIS Z 8803:2011, and is the value at 25 °C, 50 rpm, and 30 seconds, and can be measured using a cone - plate type viscometer (manufactured by Toki Sangyo Co., Ltd., TVE - 33H) with 3°×R14 as the cone - rotor.

[0015] (1) Filling container Examples of the material of the filling container include glass, metal, plastic, etc. From the viewpoints of versatility, processability, cost, airtightness, etc., plastic is preferable, and polyolefin resin is more preferable. The filling container usually consists of members such as a container body, a cap (lid), a stopper (inner stopper, etc.). The materials of these members are all preferably polyolefin resin. Examples of the polyolefin resin include polyethylene, polypropylene, and copolymers containing these as partial structures.

[0016] In addition, the filling container is preferably a light-shielding container. By being a light-shielding container, it becomes easy to store the photocurable resin composition under light-shielded conditions.

[0017] Examples of polyethylene include high-density polyethylene (HDPE: specific gravity 0.92 - 0.96, deflection temperature under load 130°C or lower), low-density polyethylene (LDPE: specific gravity 0.91 - 0.92, deflection temperature under load 100°C or lower), very-low-density polyethylene (VLDPE or ULDPE: specific gravity < 0.9), linear low-density polyethylene (LLDPE: specific gravity < 0.94), ultra-high molecular weight polyethylene (UHMW-PE: generally molecular weight 1.5 million or more), etc.

[0018] Examples of polypropylene include isotactic polypropylene, syndiotactic polypropylene, and atactic polypropylene due to differences in stereoregularity.

[0019] Examples of the copolymer having at least one selected from the group consisting of polyethylene and polypropylene as a partial structure include ethylene vinyl acetate copolymer (EVA), ethylene ethyl acrylate copolymer (EEA), etc.

[0020] One or more kinds can be selected from the above-mentioned polyolefin resins. Among them, at least one selected from the group consisting of polyethylene and polypropylene is preferable.

[0021] The shape of the filling container is not particularly limited, and commonly used shapes can be widely used. For example, cylindrical (cylindrical) and rectangular prism shapes can be used, but from the viewpoint of handling, a cylindrical shape is preferred.

[0022] The wall thickness of the filled container can be set to a desired range considering the strength and weight of the container. For example, 1 mm to 10 mm is preferred, 1 mm to 8 mm is more preferred, 2 mm to 6 mm is even more preferred, and 2 mm to 5 mm is particularly preferred. If the thickness is 1 mm or more, the strength is maintained when handling the filled container and it is less likely to deform, and if it is 10 mm or less, the container does not become too heavy and does not hinder transportation.

[0023] The capacity (contents) of the filling container can be set to a desired range considering the weight of the photocurable resin composition, ease of handling, etc. For example, 100 mL to 20,000 mL is preferred, 300 mL to 18,000 mL is more preferred, and 500 mL to 15,000 mL is even more preferred.

[0024] When the filling container is cylindrical, the ratio of the diameter of the inner bottom surface to the inner height of the cylinder (diameter / height) is not particularly limited, and examples include 0.1 to 1.5, preferably 0.3 to 1.3.

[0025] (2) Photocurable resin composition The photocurable resin composition used in the containerized photocurable resin composition of the present invention comprises a polyfunctional photopolymerizable compound having a viscosity of 1,000 mPa·s or less at 25°C and a photopolymerization initiator, and the content of the organic solvent is 1% by mass or less. Preferably, the content of the organic solvent is 0.5% by mass or less, and more preferably 0.1% by mass or less. In one embodiment, the photocurable resin composition does not contain an organic solvent (0% by mass).

[0026] <Polyfunctional photopolymerizable compounds with a viscosity of 1,000 mPa·s or less at 25°C> The photocurable resin composition contains a polyfunctional photopolymerizable compound having a viscosity of 1,000 mPa·s or less at 25°C. Examples of polyfunctional photopolymerizable compounds having a viscosity of 1,000 mPa·s or less at 25°C include photopolymerizable monomers and photopolymerizable oligomers having two or more photopolymerizable groups in one molecule and a viscosity of 1,000 mPa·s or less at 25°C. Examples of photopolymerizable groups include vinyl groups, vinyloxy groups, 1-chlorovinyl groups, isopropenyl groups, 4-vinylphenyl groups, allyloxy groups, acryloyloxy groups, methacryloyloxy groups, oxyranyl groups, and oxetanyl groups. Among these, acryloyloxy groups, methacryloyloxy groups, and allyloxy groups are preferred. The polyfunctional photopolymerizable compound having a viscosity of 1,000 mPa·s or less at 25°C is photocured by irradiation with active energy rays, thereby curing the photocurable resin composition. The number of photopolymerizable groups in one molecule of the polyfunctional photopolymerizable compound is preferably 4 or less, and more preferably 3 or less. The viscosity of the polyfunctional photopolymerizable compound at 25°C is preferably 800 mPa·s or less, and more preferably 600 mPa·s or less. The lower limit of viscosity is not particularly limited, but for example, it is 0.5 mPa·s or more.

[0027] Examples of polyfunctional photopolymerizable compounds having a viscosity of 1,000 mPa·s or less at 25°C include di(meth)acrylates of diols such as ethylene glycol, methoxytetraethylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, polyethylene glycol, and propylene glycol; polyhydric alcohols such as trimethylolpropane or their ethylene oxide adducts, propylene oxide adducts, or ε Examples include polyvalent (meth)acrylates such as caprolactone adducts; 2-(allyloxymethyl)acrylic acid esters such as methyl 2-(allyloxymethyl)acrylate, ethyl 2-(allyloxymethyl)acrylate, propyl 2-(allyloxymethyl)acrylate, and butyl 2-(allyloxymethyl)acrylate; allyl (meth)acrylate, mono-allyl maleate, di-allyl maleate, mono-allyl fumarate, di-allyl fumarate, clotyl (meth)acrylate, divinylbenzene, trivinylbenzene, ethylene glycol diallyl ether, propylene glycol diallyl ether, and butadiene. These may be used individually or in combination of two or more.

[0028] The content of polyfunctional photopolymerizable compounds having a viscosity of 1,000 mPa·s or less at 25°C in the photocurable composition is preferably 5 to 90% by mass, more preferably 7 to 70% by mass, and particularly preferably 10 to 50% by mass, based on the total amount of the photocurable resin composition, from the viewpoint of photocurability and the physical properties of the cured coating film.

[0029] <Photopolymerization initiator> As photopolymerization initiators used in photocurable resin compositions, known and conventional ones can be used without particular limitation.

[0030] Examples of photopolymerization initiators include α-aminoacetophenone-based photopolymerization initiators such as 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-1-propanone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone, N,N-dimethylaminoacetophenone, 1-hydroxycyclohexylphenyl ketone, 1-[4-( Hydroxyacetophenone-based photopolymerization initiators such as 2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one, and 2-hydroxy-2-methyl-1-phenylpropan-1-one; bis-(2,6-dichlorobenzoyl)phenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-2,5-dimethylphenyl phosphine Sphin 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, bis-(2,6-dimethoxybenzoyl)-2,5-dimethylphenylphosphine oxide, bis-(2,4,6-trimethyl Acyl phosphine oxide-based photopolymerization initiators such as benzoyl)-phenylphosphine oxide, 2,6-dimethoxybenzoyldiphenylphosphine oxide, 2,6-dichlorobenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylphosphinate methyl ester, 2-methylbenzoyldiphenylphosphine oxide, pivaloylphenylphosphinate isopropyl ester, and 2,4,6-trimethylbenzoyldiphenylphosphine oxide;Benzoin-based photopolymerization initiators such as benzoin, benzyl, benzoin methyl ether, benzoin ethyl ether, benzoin n-propyl ether, benzoin isopropyl ether, and benzoin n-butyl ether; benzoin alkyl ether-based photopolymerization initiators; benzophenone-based photopolymerization initiators such as benzophenone, p-methylbenzophenone, Michlar's ketone, methylbenzophenone, 4,4'-dichlorobenzophenone, and 4,4'-bisdiethylaminobenzophenone; acetophenone, 2,2-dimethoxy-2-phenylacetophenone Acetophenone-based photopolymerization initiators such as 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-1-propanone; thioxanthone-based photopolymerization initiators such as thioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2,4-diisopropylthioxanthone; anthraquinone Anthraquinone-based photopolymerization initiators such as chloroanthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone, and 2-aminoanthraquinone; ketal-based photopolymerization initiators such as acetophenone dimethyl ketal and benzyl dimethyl ketal; benzoic acid ester-based photopolymerization initiators such as ethyl-4-dimethylaminobenzoate, 2-(dimethylamino)ethyl benzoate, and p-dimethylbenzoate ethyl ester; 2-(O-benzoyloxime)- Oxime ester-based photopolymerization initiators such as 1-[4-(phenylthio)phenyl]-1,2-octanedione and 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]ethanone 1-(O-acetyloxime); titanocene-based photopolymerization initiators such as bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrole-1-yl)phenyl)titanium and bis(cyclopentadienyl)-bis[2,6-difluoro-3-(2-(1-pyr-1-yl)ethyl)phenyl]titanium;Examples include the following. Among these, anthraquinone-based photopolymerization initiators, acylphosphine oxide-based photopolymerization initiators, and oxime-based initiators are preferred. These may be used individually or in combination of two or more.

[0031] Commercially available α-aminoacetophenone-based photopolymerization initiators include Omnirad 907, 369, 369E, and 379 from IGM Resins. Commercially available acylphosphine oxide-based photopolymerization initiators include TPO from Kusumoto Chemicals, Inc. and Omnirad 819 from IGM Resins. Commercially available anthraquinone-based photopolymerization initiators include 2-ethyl AQ from Mitsui & Co. Chemicals, Ltd. Commercially available oxime ester-based photopolymerization initiators include Irgacure OXE01 and OXE02 from BASF Japan Ltd., N-1919 from ADEKA Corporation, ADEKA Arclus NCI-831 and NCI-831E, and TR-PBG-304 from Changzhou Strong Electronic New Materials Co., Ltd.

[0032] From the viewpoint of photocurability and the physical properties of the cured coating film, the content of the photopolymerization initiator in the photocurable resin composition is preferably 0.1 to 35% by mass, more preferably 0.5 to 30% by mass, and particularly preferably 1 to 25% by mass, based on the total amount of the photocurable resin composition.

[0033] <Photopolymerizable compounds with a viscosity of 1,500 mPa·s or higher at 25°C> In one embodiment, the photocurable resin composition may further contain a photopolymerizable compound having a viscosity of 1,500 mPa·s or more at 25°C. By adding the photopolymerizable compound, the sagging properties can be improved without impairing other properties. The photopolymerizable compound having a viscosity of 1,500 mPa·s or more at 25°C is a compound having one or more photopolymerizable groups in one molecule and having a viscosity of 1,500 mPa·s or more at 25°C. Examples of photopolymerizable groups include vinyl groups, vinyloxy groups, 1-chlorovinyl groups, isopropenyl groups, 4-vinylphenyl groups, allyloxy groups, acryloyloxy groups, methacryloyloxy groups, oxyranyl groups, oxetanyl groups, etc., with acryloyloxy groups, methacryloyloxy groups, and allyloxy groups being preferred. The viscosity of the photopolymerizable compound at 25°C is 1,500 mPa·s or more, and preferably 2,000 mPa·s or more. Furthermore, it is preferable that the pressure be 10,000 mPa·s or less.

[0034] Examples of monofunctional photopolymerizable compounds having a viscosity of 1,500 mPa·s or higher at 25°C include carboxyl group-containing (meth)acrylates such as 2-(meth)acryloyloxyethylhexahydrophthalic acid, 2-(meth)acryloyloxypropylhexahydrophthalic acid, 2-(meth)acryloyloxyethylphthalic acid, 2-(meth)acryloyloxypropylphthalic acid, 2-(meth)acryloyloxypropylhexahydrophthalic acid, 2-(meth)acryloyloxyethyl maleic acid, and 2-(meth)acryloyloxypropyl maleic acid. These may be used individually or in combination of two or more.

[0035] Examples of polyfunctional photopolymerizable compounds having a viscosity of 1,500 mPa·s or more at 25°C include polyhydric alcohols such as ditrimethylolpropane, pentaerythritol, dipentaerythritol, and tris-hydroxyethyl isocyanurate, or polyhydric (meth)acrylates such as ethylene oxide adducts, propylene oxide adducts, or ε-caprolactone adducts thereof; polyhydric (meth)acrylates such as phenoxyacrylate, bisphenol A diacrylate, and ethylene oxide adducts or propylene oxide adducts of these phenols; and polyhydric glycidyl ethers such as glycerin diglycidyl ether, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, and triglycidyl isocyanurate. Meth)acrylates; not limited to those mentioned above, these include (meth)acrylates obtained by directly (meth)acrylateing polyols such as polyether polyols, polycarbonate polyols, hydroxyl-terminated polybutadienes, and polyester polyols, or by urethane (meth)acrylateing via diisocyanate, and melamine (meth)acrylate; epoxy polyvalent (meth)acrylates such as phenol novolac epoxy (meth)acrylate, cresol novolac epoxy (meth)acrylate, and bisphenol-type epoxy (meth)acrylate; urethane polyvalent (meth)acrylate, epoxy urethane polyvalent (meth)acrylate, polyester polyvalent (meth)acrylate, polyether polyvalent (meth)acrylate, polybutadiene-modified polyvalent (meth)acrylate, etc. These may be used individually or in combination of two or more.

[0036] From the viewpoint of the physical properties of the cured coating film, the content of a photopolymerizable compound in the photocurable resin composition having a viscosity of 1,500 mPa·s or more at 25°C is preferably 1 to 95% by mass, more preferably 10 to 90% by mass, and particularly preferably 20 to 85% by mass, based on the total amount of the photocurable resin composition.

[0037] <Other photopolymerizable compounds> In one embodiment, the photocurable resin composition may further contain a photopolymerizable compound other than the polyfunctional photopolymerizable compound having a viscosity of 1,000 mPa·s or less at 25°C and the photopolymerizable compound having a viscosity of 1,500 mPa·s or more at 25°C (hereinafter also referred to as "other photopolymerizable compounds" in this specification). Examples of other photopolymerizable compounds include a polyfunctional photopolymerizable compound having a viscosity of more than 1,000 mPa·s and less than 1,500 mPa·s at 25°C, and a monofunctional photopolymerizable compound having a viscosity of less than 1,500 mPa·s at 25°C.

[0038] Examples of polyfunctional photopolymerizable compounds having a viscosity of more than 1,000 mPa·s and less than 1,500 mPa·s at 25°C include ethoxylated bisphenol A di(meth)acrylate.

[0039] Examples of monofunctional photopolymerizable compounds with a viscosity of less than 1,500 mPa·s at 25°C include alkyl(meth)acrylates such as methyl(meth)acrylate, ethyl(meth)acrylate, propyl(meth)acrylate, butyl(meth)acrylate, amyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, octyl(meth)acrylate, nonyl(meth)acrylate, dodecyl(meth)acrylate, hexadecyl(meth)acrylate, octadecyl(meth)acrylate, and cyclohexyl Cycloalkyl(meth)acrylates such as (meth)acrylate; aryl(meth)acrylates such as phenyl(meth)acrylate; benzyl(meth)acrylate, phenylbenzyl(meth)acrylate; isobornyl(meth)acrylate, dicyclopentanyl(meth)acrylate, dicyclopentenyl(meth)acrylate, dicyclopentenyloxyethyl(meth)acrylate; methoxyethyl(meth)acrylate, butoxyethyl(meth)acrylate, phenoxyethyl(meth)acrylate, nonyl(meth)acrylate Ether-containing (meth)acrylates such as phenoxyethyl (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate (e.g., methoxytriethylene glycol (meth)acrylate), butoxydiethylene glycol (meth)acrylate, and tetrahydrofurfuryl (meth)acrylate; (poly)alkylene glycol-modified (meth)acrylates such as EO-modified (meth)acrylate of 2-ethylhexanol; glycidyl (meth)acrylate; Amino group-containing (meth)acrylates such as dimethylaminoethyl (meth)acrylate and diethylaminoethyl (meth)acrylate; hydroxyl group-containing (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, and 2-hydroxy-3-phenoxypropyl (meth)acrylate; (meth)acrylic acid, carboxyethyl (meth)acrylate, crotonic acid, fumaric acid, maleic acid, itaconic acid, monomethyl maleate, monomethyl itaconic acid;Acrylamides such as N-[2-(acryloyloxy)ethyl]phthalimide, N-[2-(acryloyloxy)ethyl]tetrahydrophthalimide, acrylamide, N-isopropylacrylamide, N,N-dimethylacrylamide, N,N-diethylacrylamide, diacetone acrylamide, 4-acryloylmorpholine, N-tert-butylacrylamide, N-hydroxymethylacrylamide, N-hydroxyethylacrylamide, N-tert-octylacrylamide, N-butoxymethylacrylamide, N-phenylacrylamide, N-dodecylacrylamide, etc.; styrene, p-methylstyrene, Examples include aromatic vinyl monomers such as o-methylstyrene and vinylnaphthalene; unsaturated nitrile monomers such as acrylonitrile; olefin monomers such as ethylene and propylene; halogenated vinyl monomers such as vinyl chloride, vinylidene chloride, and vinylidene fluoride; unsaturated carboxylic acid monomers such as acrylic acid, methacrylic acid, and maleic anhydride; vinyl acetate; maleimide monomers such as N-propyl maleimide, N-cyclohexyl maleimide, and No-chlorophenyl maleimide; and carboxyl group-containing (meth)acrylates such as 2-(meth)acryloyloxyethyl succinic acid and 2-(meth)acryloyloxypropyl succinic acid. These may be used individually or in combination of two or more.

[0040] From the viewpoint of the physical properties of the cured coating film, the content of other photopolymerizable compounds in the photocurable resin composition is preferably 0 to 95% by mass, more preferably 10 to 85% by mass, and particularly preferably 20 to 75% by mass, based on the total amount of the photocurable resin composition.

[0041] <Inorganic filler> In one embodiment, the photocurable resin composition may further contain an inorganic filler. Adding an inorganic filler can improve adhesion to the substrate. Any known or commonly used inorganic filler can be used without particular limitation.

[0042] Examples of inorganic fillers include silica such as talc, amorphous silica, crystalline silica, fused silica, and spherical silica; kaolin, montmorilloid, montmorillonite, clay, Neuburg silica particles, boehmite, synthetic mica, hydrotalcite, zeolite, silicon nitride, aluminum nitride, calcium zirconate, aluminum hydroxide, magnesium hydroxide, zinc oxide, magnesium oxide, aluminum oxide, neodymium oxide, antimony oxide, titanium oxide, cerium oxide, calcium sulfate, barium sulfate, barium titanate, calcium carbonate, calcium silicate, lithium carbonate, gold, aluminum, copper, nickel, carbon black, carbon nanotubes, and graphite. Among these, silica, talc, and barium sulfate are preferred. These may be used individually or in combination of two or more.

[0043] The shape of the inorganic filler is not particularly limited and can be spherical, fibrous, plate-shaped, amorphous, balloon-shaped, etc. The average particle size of the inorganic filler is also not particularly limited and can be, for example, 0.01 to 3.0 μm. Furthermore, the inorganic filler may be subjected to various surface treatments, such as insulation treatment or high-dispersibility treatment, as needed.

[0044] The inorganic filler content in the photocurable resin composition is preferably 10 to 60% by mass, more preferably 20 to 50% by mass, and even more preferably 25 to 40% by mass, based on the total amount of the photocurable resin composition.

[0045] <Radical polymerization inhibitor> In one embodiment, the photocurable resin composition may further contain a radical polymerization inhibitor. Adding a radical polymerization inhibitor can suppress the thickening of the photocurable resin composition. Known and commonly used radical polymerization inhibitors can be used without particular limitation, and examples include naphthalene derivatives, naphthoquinone and its derivatives, phenolic compounds, nitroso compounds, N-oxide compounds, quinone compounds, N-oxyl compounds, phenothiazine compounds, and hindered phenolic compounds. Among these, naphthalene derivatives, naphthoquinone and its derivatives, and phenolic compounds are preferred.

[0046] Examples of naphthalene derivatives include ammonium 1,4-dihydroxy-2-naphthalenesulfonate and 4-methoxy-1-naphthol. Examples of naphthoquinone and its derivatives include 1,4-naphthoquinone, 2-hydroxy-1,4-naphthoquinone, and anthrone. Examples of commercially available naphthalene derivatives include Kinopower® QS-30, WSI, and Kinopower MNT (manufactured by Air Water Performance Chemical Co., Ltd.). Examples of commercially available naphthoquinone and naphthoquinone derivatives include Kinopower® NQI, Kinopower LSN, Kinopower ATR (manufactured by Air Water Performance Chemical Co., Ltd.), 1,4-naphthoquinone, 2-hydroxy-1,4-naphthoquinone, and anthrone (all manufactured by Tokyo Chemical Industry Co., Ltd.).

[0047] Examples of phenolic compounds include hydroquinone, p-methoxyphenol, 4-tert-butylcatechol, hydroquinone monomethyl ether, 2,6-di-tert-butylphenol, 2,6-di-tert-butyl-4-methylphenol, 2,4,6-tri-tert-butylphenol, 2,6-di-tert-butyl-4-ethylphenol, 4-sec-butyl-2,6-di-tert-butylphenol, 4,4'-methylenebis(2,6-di-tert-butylphenol), 2,4,6-tris(3',5'-di-tert-butyl-4'-hydroxybenzyl)mesitylene, and 2,2',6,6'-tetra-tert-butyl-4,4'-dihydroxybiphenyl.

[0048] The amount of radical polymerization inhibitor in the photocurable resin composition is preferably 0.01 to 1% by mass relative to the total amount of the photocurable resin composition.

[0049] <Additives> The photocurable resin composition of the present invention may optionally contain additives such as surfactants, co-sensitizers, ultraviolet absorbers, antioxidants, ion catchers, coupling agents, tackifiers, surface modifiers, leveling agents, defoamers, rheology control agents, and colorants, to the extent that the effects of the present invention are exhibited.

[0050] The content of the additive in the photocurable resin composition of the present invention is preferably 0.1 to 10% by mass, and more preferably 1 to 5% by mass, based on the total amount of the photocurable resin composition.

[0051] <Preparation of photocurable resin composition> The photocurable resin composition is prepared by mixing a polyfunctional photopolymerizable compound having a viscosity of 1,000 mPa·s or less at 25°C with a photopolymerization initiator, and optionally a photopolymerizable compound having a viscosity of 1,500 mPa·s or more at 25°C, other photopolymerizable compounds, inorganic fillers, radical polymerization inhibitors, and additives, to form a homogeneous liquid composition. After preparation, it is filled into a container so that the volume filling rate is 90 vol% or less.

[0052] The viscosity of the photocurable resin composition of the present invention at 25°C is preferably 300 dPa·s or less from the viewpoint of coatability. The preferred viscosity range varies depending on the coating method. For example, in the case of the inkjet method, the viscosity at 25°C is preferably 1.5 dPa·s or less, more preferably 1.0 dPa·s or less, and particularly preferably 0.5 dPa·s or less. The lower limit of viscosity is not particularly limited, but from the viewpoint of controlling the thickness of the coating film, the viscosity at 25°C is preferably 0.01 dPa·s or more. Furthermore, when using a jet dispenser, the viscosity at 25°C is preferably 300 dPa·s or less, more preferably 250 dPa·s or less, and particularly preferably 200 dPa·s or less. From the viewpoint of coatability, the lower limit of viscosity is preferably 10 dPa·s or more at 25°C. Furthermore, "viscosity" can be measured in accordance with JIS Z 8803:2011, section 10, "Method for measuring viscosity using a cone-plate rotational viscometer," at 25°C, 50 rpm, and 30 seconds, using a 3°×R14 cone rotor and a cone-plate viscometer (Toki Sangyo Co., Ltd., TVE-33H).

[0053] In one embodiment, a photocurable resin composition is provided for filling a container with a volume filling rate of 90 vol% or less. The photocurable resin composition can be applied without particular limitation to the embodiments described above.

[0054] <Applications of photocurable resin compositions> The photocurable resin composition is not particularly limited as long as it contains a polyfunctional photopolymerizable compound having a viscosity of 1,000 mPa·s or less at 25°C and a photopolymerization initiator. Typical examples include solder resist inks, etching resist inks, substrate edge protection resist inks, plating resist inks, interlayer insulating materials, hole-filling materials, and the like.

[0055] There are no particular limitations on the method for applying the photocurable resin composition to the substrate, but examples include the inkjet method, dispenser method, dip coat method, flow coat method, roll coat method, bar coater method, screen printing method, and curtain coat method. Among these, the inkjet method is preferred from the viewpoint of high-definition patterning. Furthermore, the dispenser method, and especially the jet dispenser method, is preferred from the viewpoint of the degree of freedom in the location of coating film formation and the physical properties of the coating film.

[0056] Examples of substrates include printed circuit boards and flexible printed circuit boards with circuits pre-formed using copper, as well as copper-clad laminates using paper phenol, paper epoxy, glass cloth epoxy, glass polyimide, glass cloth / nonwoven epoxy, glass cloth / paper epoxy, synthetic fiber epoxy, fluororesin / polyethylene / polyphenylene ether, polyphenylene oxide / cyanate, etc., and other materials such as metal substrates, polyimide films, PET films, polyethylene naphthalate (PEN) films, glass substrates, ceramic substrates, and wafers.

[0057] By irradiating the above coating with ultraviolet light, a cured product can be formed.

[0058] The peak wavelength of the ultraviolet light used for irradiation is typically 200-450 nm, preferably 250-420 nm, and more preferably 300-405 nm.

[0059] Examples of light sources for ultraviolet irradiation include UV-LEDs (light-emitting diodes), UV-LDs (laser diodes), mercury lamps, metal halide lamps, and ultraviolet fluorescent lamps. Of these, UV-LEDs and UV-LDs are preferred from the viewpoint of being small, having a long lifespan, and being highly efficient.

[0060] The cumulative amount of ultraviolet light (UV exposure) varies depending on the thickness of the coating film, but is generally between 10 and 10,000 mJ / cm². 2 The concentration is preferably 20-5000 mJ / cm². 2 More preferably 50-2000 mJ / cm²2 That is the case.

[0061] (3) How to save In one embodiment, a method for storing a photocurable resin composition is provided. In this storage method, the photocurable resin composition is filled into a container such that the volume filling rate is 90 vol% or less relative to the container's capacity, and stored under light-shielding conditions. The photocurable resin composition contains a polyfunctional photosensitive monomer and a photopolymerization initiator, and the content of the organic solvent is 1 wt% or less.

[0062] For the photocurable resin composition, those described in "(2) Photocurable resin composition" can preferably be used. Furthermore, for the filling container, those described in "(1) Filling container" can preferably be used.

[0063] The volumetric filling ratio of the photocurable resin composition relative to the capacity of the filling container is 90 vol% or less, preferably 87 vol% or less, and more preferably 85 vol% or less. A volumetric filling ratio exceeding 90 vol% is undesirable because it tends to thicken the photocurable resin composition, reducing its storage stability. The "volumetric filling ratio" is a value calculated from the capacity of the plastic container and the volume of the resin composition at 10 to 30°C (especially 22°C).

[0064] As for light-shielding conditions, it is most preferable to block all wavelengths by covering the photocurable resin composition with an opaque material, but it is also acceptable to use a material that can block wavelengths of 450 nm or less. In one embodiment, it is preferable that the filling container is a light-shielding container made of plastic.

[0065] By storing the photocurable resin composition using this method, the thickening of the photocurable resin composition can be suppressed, resulting in good storage stability.

[0066] In one embodiment, when the above storage method is implemented, the viscosity increase after storage at 50°C for 7 days is preferably 50% or less, more preferably 40% or less, even more preferably 30% or less, particularly preferably 20% or less, and most preferably 15% or less. Good storage stability is achieved within this range. The "viscosity increase" is calculated by measuring the viscosity of the photocurable resin composition at the initial stage of preparation (initial viscosity) and the viscosity after filling it into a container, storing it in a constant temperature bath at 50°C for 7 days, and then returning it to 25°C (viscosity after storage at 50°C), and then measuring these values ​​according to the following formula. Viscosity increase (%) = {(Viscosity after storage at 50°C - Initial viscosity) / (Initial viscosity)} × 100 Furthermore, "viscosity" can be measured in accordance with JIS Z 8803:2011, section 10, "Method for measuring viscosity using a cone-plate rotational viscometer," at 25°C, 50 rpm, and 30 seconds, using a 3°×R14 cone rotor and a cone-plate viscometer (Toki Sangyo Co., Ltd., TVE-33H). [Examples]

[0067] The present invention will be further described below with reference to examples, but the present invention is not limited thereto.

[0068] <Materials used> • AOMA: Manufactured by Nippon Shokubai Co., Ltd., 2-(allyloxymethyl)methyl acrylate, bifunctional photopolymerizable monomer, 2 mPa·s @ 25℃ • TMPTA: Manufactured by Daicel Ornex Corporation, trimethylolpropane triacrylate, trifunctional photopolymerizable monomer, 80 mPa·s @ 25℃ • Arronix M-408: Manufactured by Toagosei Co., Ltd., ditrimethylolpropanetetraacrylate, tetrafunctional photopolymerizable monomer, 570 mPa·s @ 25℃ • HDDA: Manufactured by Osaka Organic Industries Co., Ltd., 1,6-hexanediol diacrylate, bifunctional photopolymerizable monomer, 7 mPa·s @ 25℃ • NK Ester A-NOD-N: Manufactured by Shin-Nakamura Chemical Industry Co., Ltd., 1,9-nonanediol diacrylate, bifunctional photopolymerizable monomer, 8 mPa·s @ 25℃ • Evecryl 270: Manufactured by Daicel Ornex Co., Ltd., bifunctional urethane acrylate, Mw: 1500, 3000 mPa·s @ 60℃ HOA-MPL(N): Manufactured by Kyoeisha Chemical Co., Ltd., a mixture of carboxyl group-containing monofunctional acrylate, 2-acryloyloxyethyl phthalic acid, etc., Mw: 269, 7000 mPa·s @ 25℃ HOA-HH(N): Manufactured by Kyoeisha Chemical Co., Ltd., carboxyl group-containing monofunctional acrylate, 2-acryloyloxyethylhexahydrophthalic acid, Mw: 270, 4500 mPa·s @ 25℃ • DPHA: Dipentaerythritol hexaacrylate, hexafunctional photopolymerizable monomer, 6500 mPa·s @ 25℃ • Aronix M-120: Manufactured by Toagosei Co., Ltd., EO2 molar added 2-ethylhexyl acrylate, monofunctional photopolymerizable monomer, 7 mPa·s @ 25℃ • 2-Ethyl AQ: Manufactured by Mitsui & Co. Chemicals, Ltd., 2-ethylanthraquinone, photopolymerization initiator TPO: 2,4,6-trimethylbenzoylphenylphosphinate methyl ester, manufactured by Kusumoto Chemical Co., Ltd., photopolymerization initiator. • Spectra K: Manufactured by Paudex Corporation, silane coupling treated talc • Barium sulfate 110: Manufactured by Sakai Chemical Industry Co., Ltd., barium sulfate • p-Methoxyphenol: Radical polymerization inhibitor • Kinopower (registered trademark) QS-30: Manufactured by Air Water Performance Chemicals Inc., radical polymerization inhibitor, 4-methoxy-1-naphthol • Carbitol acetate: Organic solvent

[0069] <Examples 1-17, Comparative Examples 1-3> The photocurable resin compositions of Examples 1-17 and Comparative Examples 1-3 were prepared by mixing each component in the proportions and compositions shown in Tables 1 and 2 below, then finely dispersing the initiator and other components using a three-roll mill, filtering the resulting composition through a 10 μm aperture filter, and finally degassing it using a centrifugal degasser at 1800 rpm for 2 minutes. Unless otherwise specified, the numerical values ​​in Tables 1 and 2 refer to "parts by mass". Each of the prepared photocurable resin compositions was evaluated as described below. The results are shown in Tables 1 and 2.

[0070] <Viscosity> In accordance with JIS Z 8803:2011, section 10, "Method for measuring viscosity using a cone-plate rotational viscometer," the values ​​were measured at 25°C, 50 rpm, and 30 seconds. A 3°×R14 cone rotor was used, and measurements were taken using a cone-plate viscometer (TVE-33H, manufactured by Toki Sangyo Co., Ltd.).

[0071] <Filling rate> The weight of the photocurable resin composition was measured and filled into the containers so that its volume matched the specified value relative to the capacity of the filling containers listed in the table. The weight of the photocurable resin composition was calculated using the density of the photocurable resin composition with the following formula. Weight of photocurable resin composition (g) = Required volume of photocurable resin composition (mL) × Density of photocurable resin composition (g / mL)

[0072] <Thickness percentage (%)> The initial viscosity of the photocurable resin composition was measured immediately after preparation. The photocurable resin composition was then sealed in a black plastic container and stored in a 50°C constant temperature bath for 7 days. Afterward, it was removed from the bath and allowed to cool to 25°C. After cooling, the viscosity of the photocurable resin composition was measured, and the viscosity increase rate (%) was calculated using the following formula. The obtained viscosity increase rate (%) was evaluated according to the following criteria. Viscosity increase (%) = {(Viscosity after storage at 50°C - Initial viscosity) / (Initial viscosity)} × 100 ◎: Thickening rate less than 15% ○: Thickening rate of 15% or more but less than 20% △: Thickening rate is 20% or more but less than 50% ×: Thickening rate of 50% or more

[0073] <Laziness> 0.5 mL of the composition was dispensed onto a buffed copper-clad substrate using a syringe. The substrate was then placed upright at room temperature, and the amount of composition that flowed was measured. The sagging properties of the composition were evaluated based on the amount flowed, according to the following criteria. ◎: The amount of composition that flowed was less than 2 cm. ○: The amount of composition that flowed was 2 cm or more but less than 5 cm. △: The amount of composition that flowed was 5 cm or more but less than 10 cm. ×: The amount of the composition that flowed was 10 cm or more.

[0074] <Method for preparing substrates for evaluating cured coatings> On a buffed and flattened copper-clad substrate, a jet dispenser with a 0.3mm diameter nozzle was used to apply the composition in a 20mm x 20mm x 20μm square, with a distance of 1mm from the nozzle tip to the substrate. Subsequently, 1,000 mJ / cm² was applied using an LED (365nm). 2 The substrate was irradiated and used for evaluating the cured coating.

[0075] <Dryness to the touch> The touch-dry properties of the cured coatings prepared using the above-described substrate preparation method were evaluated according to the following criteria. ◎: The cured coating is completely non-sticky. ○: The hardened coating has a slight stickiness. △: The cured coating is noticeably sticky. ×: The hardened coating has a strong sticky texture.

[0076] <Adhesion to copper> Using the above-described method for preparing a substrate for evaluating cured coating films, 100 grids were formed on the cured coating film using a 1 mm wide cross-cut guide. Cellophane tape peeling was then performed on top of these grids, and the number of remaining grids was evaluated according to the following criteria. ○: The number of remaining squares is 90 or more. △: The number of remaining squares is 60 or more but less than 90. ×: The number of remaining squares is less than 60.

[0077] <Pencil hardness> The cured coating film prepared using the above-described method for preparing a substrate for evaluating cured coating films was scratched with a pencil while applying a 1 kg load according to the method described in JIS K5600, and evaluated by the hardness of the pencil until the underlying copper was visible.

[0078] <Etching resistance> The cured coating film prepared using the above-described method for preparing a substrate for evaluating the cured coating film was immersed in a ferric chloride solution at 40°C for 5 minutes, and the state of the cured coating film was then visually evaluated. ◎: The cured coating film is not affected at all by the ferric chloride solution. ○: The cured coating film is hardly eroded by the ferric chloride solution. △: The hardened coating film is slightly eroded by the ferric chloride solution. ×: The hardened coating film has been completely eroded by the ferric chloride solution.

[0079] [Table 1]

[0080] [Table 2]

[0081] The containerized photocurable resin compositions of Examples 1 to 17 all showed good results in terms of viscosity, sagging, touch-dryness, adhesion, pencil hardness, and etching resistance. On the other hand, the containerized photocurable resin compositions of Comparative Examples 1 to 3 were outside the scope of the present invention and showed inferior results compared to the present invention in at least one of the following areas: high viscosity, poor sagging, poor touch-dryness, low adhesion, poor etching resistance, etc. Although Comparative Examples 2 and 3 showed good results in viscosity evaluation, this is thought to be because their compositions were inherently difficult to thicken, such as not containing a polyfunctional photopolymerizable compound (Comparative Example 2) or containing a solvent (Comparative Example 3).

Claims

1. A containerized photocurable resin composition, which is filled in a container, The aforementioned photocurable resin composition comprises a polyfunctional photopolymerizable compound having a viscosity of 1,000 mPa·s or less at 25°C, and a photopolymerization initiator, and the content of the organic solvent is 1% by mass or less. A photocurable resin composition in a container, wherein the volume filling rate of the photocurable resin composition relative to the capacity of the filling container is 90 vol% or less.

2. The containerized photocurable resin composition according to claim 1, wherein the material of the filling container is a polyolefin resin.

3. The containerized photocurable resin composition according to claim 2, wherein the polyolefin resin is polyethylene or polypropylene.

4. The containerized photocurable resin composition according to claim 1, wherein the photocurable resin composition further contains a photopolymerizable compound having a viscosity of 1,500 mPa·s or more at 25°C.

5. The containerized photocurable resin composition according to claim 1, wherein the photocurable resin composition further contains an inorganic filler.

6. The containerized photocurable resin composition according to claim 1, wherein the photocurable resin composition further contains a radical polymerization inhibitor.

7. The containerized photocurable resin composition according to claim 1, wherein the viscosity of the photocurable resin composition at 25°C is 300 dPa·s or less.

8. The container-packaged photocurable resin composition according to claim 1, wherein the filling container is a light-shielding container.

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