WO2017170932A1

WO2017170932A1 - Curable composition, conformal coating agent and cured product

Info

Publication number: WO2017170932A1
Application number: PCT/JP2017/013398
Authority: WO
Inventors: 謙太郎北澤; 堤　洋介; 孝彦佃; 伸行松岡
Original assignee: ハリマ化成株式会社
Priority date: 2016-03-31
Filing date: 2017-03-30
Publication date: 2017-10-05
Also published as: CN109071695B; CN109071695A; JP6697306B2; JP2017179171A

Abstract

The present invention provides a curable composition which enables the achievement of a cured product that has excellent cracking resistance even in an insufficiently photocured portion, while exhibiting excellent electrical insulation properties. A curable composition according to the present invention contains a urethane resin (A) having a hydrogenated butadiene skeleton and/or a hydrogenated isoprene skeleton, a monofunctional (meth)acrylate (B) containing no ring structure and having an alkyl group with 10 or less carbon atoms, and a photopolymerization initiator (C). The urethane resin (A) is a polymer containing a polyol (a1-1) component and a polyisocyanate (a2) component, which is a polymer of a monomer having an equivalent ratio (isocyanate groups/hydroxyl groups) within a predetermined range; and the polyisocyanate (a2) component contains a polyisocyanate that has an alicyclic structure of non-fused 2 to 6 monocyclic rings or an aromatic ring of non-fused 3 to 7 monocyclic rings.

Description

Curable composition, conformal coating agent and cured product

The present invention relates to a curable composition, a conformal coating agent, and a cured product.

Conventionally, in the field of electronic materials, in order to protect an electronic circuit board from water, moisture, dust, and the like, an electrical insulation process may be performed on the electronic circuit board after soldering.

Various curable compositions used for applying insulation treatment have been proposed. For example, Patent Document 1 discloses (meth) acrylate oligomer (A) having an average of 1.5 or more (meth) acryloyl groups in one molecule and a diene-based or hydrogenated diene-based skeleton. A compound having one (meth) acryloyl group whose homopolymer has a glass transition temperature of 50 ° C. or less, a compound having no isocyanate-reactive group (B), and a compound having two or more isocyanate groups (C ) And a photopolymerization initiator (D) having no isocyanate-reactive group, which is a photocuring type combined with moisture curing for coating an electronic circuit containing components (A) to (D) in a specific ratio Compositions have been proposed.

Patent Document 2 discloses a photocurable drip-proof material used as a material for forming a coating film that covers a flux residue in a soldering portion, and includes (A) hydrogenated polybutadiene acrylate and (B) isocyanate in one molecule. A photocurable drip-proof material characterized by containing each component of a polyisocyanate having 3 or more groups, (C) a reactive solvent, and (D) a photopolymerization initiator has been proposed.

Patent Document 3 includes (a) an organic polyisocyanate compound and (b) a polyester polyol having a number average molecular weight of 8000 or less and containing at least one of dimer acid, dimer diol and hydrogenated compounds as a copolymer component. Is reacted so that the NCO / OH ratio of (a) / (b) is 1.8 to 2.3, and 50 to 90% of the number of terminal NCO groups of the polyurethane prepolymer obtained is photopolymerizable ( A one-component photo-curing and moisture-curing combined coating agent modified with a (meth) acryloyl group has been proposed.

JP 2014-201593 A JP 2012-121935 A JP 2008-159437 A

However, the moisture-curing combined photo-curable composition of Patent Document 1 has insufficient electrical insulation and transparency in both the ultraviolet irradiation part and the ultraviolet non-irradiation part of the cured product, and is not moisture curable. It has the problem of being sufficient.

The photocurable drip-proof material of Patent Document 2 also has a problem that electrical insulation is insufficient in both the ultraviolet irradiation part and the ultraviolet non-irradiation part of the cured product.

The one-component photocuring / moisture-curing combined coating agent of Patent Document 3 has insufficient electrical insulation in both the ultraviolet irradiation part and the ultraviolet non-irradiation part of the cured product, and the ultraviolet irradiation part and the ultraviolet ray of the cured product. Any of the non-irradiated portions has a problem that cracks occur due to expansion and contraction due to changes in temperature (low crack resistance).

In the cured product, the cured product has excellent electrical insulation and crack resistance in both irradiated and non-irradiated portions of active energy rays such as ultraviolet rays, and the cured product has high transparency and active energy. A curable composition using both moisture curing and photocuring that is sufficiently cured (excellent in moisture curable property) even when irradiation with rays is insufficient, and a conformal coating agent using the curable composition and Provide a cured product.

The curable composition of the present invention has a hydrogenated butadiene-based skeleton and / or a hydrogenated isoprene-based skeleton, and contains a hydrogenated polybutadiene polyol and / or a hydrogenated polyisoprene polyol (a1- 1) a polymer containing an alcohol (a1) containing polyisocyanate (a2) as monomer components, the equivalent ratio of isocyanate groups in the polyisocyanate (a2) to hydroxyl groups in the alcohol (a1) ( (Isocyanate group / hydroxyl group) is a polymer of a monomer having a value greater than 1 and 8 or less, and the polyisocyanate (a2) has 2 to 6 monocyclic alicyclic structures or 3 Urethane resin (A) containing polyisocyanate having ˜7 monocyclic aromatic rings;
A monofunctional (meth) acrylate (B) having no ring structure and having an alkyl group having 10 or less carbon atoms;
And a photopolymerization initiator (C).

That is, the curable composition of the present invention comprises a urethane resin (A) having a hydrogenated butadiene skeleton and / or a hydrogenated isoprene skeleton,
A monofunctional (meth) acrylate (B) having no ring structure and having an alkyl group having 10 or less carbon atoms;
A curable composition comprising a photopolymerization initiator (C),
The urethane resin (A) is a polymer containing, as monomer components, an alcohol (a1) containing a polyol (a1-1) containing a hydrogenated polybutadiene polyol and / or a hydrogenated polyisoprene polyol, and a polyisocyanate (a2). The equivalent ratio of the isocyanate group in the polyisocyanate (a2) to the hydroxyl group in the alcohol (a1) containing the alcohol (a1) and the polyisocyanate (a2) (isocyanate group / hydroxyl group) is 1 A polymer of a monomer having a size of 8 or less, and the polyisocyanate (a2) has 2 to 6 monocyclic alicyclic structures or 3 to 7 monocyclic aromatics in one molecule. A polyisocyanate having a ring is included.

Since the curable composition of the present invention has the above-described configuration, a cured product having excellent electrical insulation and excellent crack resistance even in a portion where light curing is insufficient is obtained. be able to.

The curable composition of the present invention includes a urethane resin (A) having a hydrogenated butadiene-based skeleton and / or a hydrogenated isoprene-based skeleton, and an alkyl group having no ring structure and having 10 or less carbon atoms. A monofunctional (meth) acrylate (B) having a photopolymerization initiator (C).

[Urethane resin (A)]
The urethane resin (A) has a hydrogenated butadiene skeleton (hydrogenated butadiene skeleton) and / or a hydrogenated isoprene skeleton (hydrogenated isoprene skeleton).

The urethane resin (A) is a polymer containing, as monomer components, an alcohol (a1) containing a polyol (a1-1) containing a hydrogenated polybutadiene polyol and / or a hydrogenated polyisoprene polyol and a polyisocyanate (a2). . That is, the urethane resin (A) is a polymer of a monomer containing an alcohol (a1) containing a polyol (a1-1) containing a hydrogenated polybutadiene polyol and / or a hydrogenated polyisoprene polyol and a polyisocyanate (a2). .

Examples of the hydrogenated polybutadiene polyol include hydrogenated products of polybutadiene diol. Hydrogenated polybutadiene diols are, for example, trade names “GI-1000” and “GI-2000” and trade name “GI-3000” from Nippon Soda Co., Ltd., trade names “Krazol HLBH-P2000” and trade names from Clay Valley. It is commercially available under the name “Krasol HLBH-P3000”. Hydrogenated polybutadiene polyols may be used alone or in combination of two or more.

In the hydrogenated polybutadiene polyol, part or all of the unsaturated double bonds contained in the polybutadiene polyol are hydrogenated. The degree of hydrogenation of the hydrogenated polybutadiene polyol can be determined by the iodine value. The iodine value of the hydrogenated polybutadiene polyol is preferably 50 or less, more preferably 40 or less, particularly preferably 30 or less, and most preferably 25 or less. In the present invention, the iodine value is a value obtained by converting the amount of halogen to be bonded to the number of g of iodine when halogen is reacted with 100 g of a sample, and can be measured by a method defined in JIS K0070. it can.

Examples of the hydrogenated polyisoprene polyol include hydrogenated products of polyisoprene diol. Hydrogenated polyisoprene is commercially available, for example, from Idemitsu Kosan Co., Ltd. under the trade name “EPOL”. Hydrogenated polyisoprene polyols may be used alone or in combination of two or more.

In the hydrogenated polyisoprene polyol, part or all of the unsaturated double bond contained in the polyisoprene polyol is hydrogenated. The degree of hydrogenation of the hydrogenated polyisoprene polyol can be determined by the iodine value. The iodine value of the hydrogenated polyisoprene polyol is preferably 40 or less, more preferably 30 or less, particularly preferably 20 or less, and most preferably 10 or less.

Since the cured product of the curable composition is excellent in electrical insulation, hydrogenated polybutadiene polyol is preferable. Since the cured product of the curable composition has excellent crack resistance, hydrogenated polyisoprene polyol is preferred.

The number average molecular weight of the polyol (a1-1) is preferably 500 to 10,000, more preferably 1000 to 5000, and still more preferably 2100 to 4000. When the number average molecular weight is 500 or more, the crack resistance and electrical insulation of the cured product of the curable composition are improved. When the number average molecular weight is 10,000 or less, the adhesiveness of the cured product immediately after curing of the curable composition is reduced, and the protective performance of the cured product resulting from adhesion of metal powder and dust in the atmosphere to the cured product. The decrease can be suppressed.

The number average molecular weight of the polyol (a1-1) refers to a value obtained by converting the molecular weight measured by gel permeation chromatography (GPC) into polystyrene. For example, it can be measured under the following measurement conditions.
Equipment: HLC-8220GPC manufactured by Tosoh Corporation
Column: product name “TSKgel SuperHZM-H” manufactured by Tosoh Corporation Column temperature: 40 ° C.
Eluent: Tetrahydrofuran Detection: RI
Standard polystyrene for calibration curve: Trade name “TSKgel standard polystyrene” manufactured by Tosoh Corporation

The content of the polyol (a1-1) component in the urethane resin (A) is preferably 1 to 99% by mass, more preferably 20 to 95% by mass, and particularly preferably 30 to 85% by mass.

The urethane resin (A) may contain a hydroxyl group-containing (meth) acrylate (a1-2) as a monomer component. When the urethane resin (A) contains a hydroxyl group-containing (meth) acrylate as a monomer component, a monofunctional (meth) acrylate and, if necessary, are added to the crosslinked structure formed by the urethane resin (A). The cross-linked structure formed by the polyfunctional (meth) acrylate can be incorporated. And the external appearance property (transparency) of the hardened | cured material of a curable composition improves. In addition, (meth) acrylate means an acrylate or a methacrylate.

The hydroxyl group-containing (meth) acrylate (a1-2) is not particularly limited, and examples thereof include hydroxyl groups such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate. Containing alkyl (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, trimethylolpropane di (meth) acrylate, Ditrimethylolpropane di (meth) acrylate, ditrimethylolpropane tri (meth) acrylate, tris-2-hydroxyethyl isocyanurate di (meth) acrylate, glycerin di ( ) Acrylate, diglycerin di (meth) acrylate, diglycerin tri (meth) acrylate, and adducts thereof (including random oxides and block adducts) such as alkylene oxides (ethylene oxide, propylene oxide, etc.). A functional (meth) acrylate etc. are mentioned, Pentaerythritol tri (meth) acrylate is preferable and Pentaerythritol triacrylate is more preferable. The hydroxyl group-containing (meth) acrylate (a1-2) may be used alone or in combination of two or more.

The content of the hydroxyl group-containing (meth) acrylate (a1-2) component in the urethane resin (A) is preferably 0.1 to 5% by mass, more preferably 0.5 to 3% by mass, and 0.8 to 2%. Mass% is particularly preferred. When the content of the hydroxyl group-containing (meth) acrylate (a1-2) component is 0.1% by mass or more, the appearance of the cured product of the curable composition is improved. When the content of the hydroxyl group-containing (meth) acrylate (a1-2) component is 5% by mass or less, the crack resistance of the cured product of the curable composition is improved.

The content of the alcohol (a1) component in the urethane resin (A) is preferably 1 to 99% by mass, more preferably 20 to 95% by mass, and particularly preferably 30 to 85% by mass.

When the hydroxyl group-containing (meth) acrylate (a1-2) is contained as a monomer component of the urethane resin (A), the alcohol (a1) component includes a polyol (a1-1) and a hydroxyl group-containing (meth) acrylate. (A1-2) is included.

The alcohol (a1) component may further contain other alcohol components in addition to the polyol (a1-1) and the hydroxyl group-containing (meth) acrylate (a1-2) as long as the object of the present invention is not impaired. . Examples of other alcohol components include polycarbonate polyol, polyester polyol, polylactone polyol, acrylic polyol, polyether polyol, and polyacetal polyol. Further, as other alcohol components, low molecular weight polyols such as ethylene glycol, diethylene glycol, 1,4-butanediol, 1,6-hexanediol, glycerin, trimethylolpropane, and pentaerythritol can be used.

In the alcohol (a1) component, the total content of the polyol (a1-1) and the hydroxyl group-containing (meth) acrylate (a1-2) is preferably 50% by mass or more, more preferably 60% by mass or more, and 70 More preferably, it is more preferably 80% by weight or more, particularly preferably 90% by weight or more, and most preferably 100% by weight.

The polyisocyanate (a2) has a plurality of isocyanate groups (—NCO) in one molecule, and further contains 2 to 6 monocyclic alicyclic structures or 3 to 7 It contains a polyisocyanate having a single aromatic ring. Polyisocyanate can form an isocyanurate or biuret body with three molecules. A trimer adduct is formed by the reaction of trimethylolpropane with three molecules of polyisocyanate.

Monocyclic means that the structure does not include a polycyclic compound structure. A polycyclic compound is a compound in which two or more rings share one or more atoms, and specific examples include fused ring compounds, bridged ring compounds, and spiro ring compounds. The condensed ring compound refers to a ring compound having orthocondensation such as naphthalene and phenanthrene, and orthopericondensation such as pyrene and perylene. A bridged ring compound is a ring structure in which carbons are bonded in a cyclic manner, such as bicyclo [4.3.1] decane, tricyclo [2.2.1.0 ^2,6 ] heptane, etc. In the structure, one or more heteroatoms may be contained), and two or more rings having no aromaticity share one or more sides of each ring and two or more atoms. The condensed alicyclic hydrocarbon compound. Spiro ring compounds are two ring structures in which one atom is bonded to a ring of carbon (such as spiro [3.4] octane, spiro [4.5] deca-1,6-diene). It refers to a ring compound having a point bond (spiro bond) that is shared by a structure in which one or more heteroatoms may be contained in a structure in which carbon is bonded in a cyclic manner.

The alicyclic structure is a structure in which carbon is bonded in a cyclic manner and has no aromaticity. The polyisocyanate used in the present invention may contain an isocyanurate ring in the structure, but the isocyanurate ring is not included in the alicyclic structure defined herein. One or two heteroatoms may be contained in the structure in which carbons are bonded in a cyclic manner. Examples of alicyclic structures include cycloalkane structures such as cyclopropane structure, cyclobutane structure, cyclopentane structure and cyclohexane structure (cycloparaffin structure), cyclobutene structure, cyclopentene structure, cyclohexene structure and cyclopropene structure. A cycloalkane structure having 5 or more carbon atoms is preferable, and a cycloalkane structure having 5 to 7 carbon atoms is more preferable.

The number of alicyclic structures in one molecule in the polyisocyanate (a2) is 2 to 6 and preferably 2 because the electrical insulation of the cured product of the curable composition is improved.

Examples of the polyisocyanate having 2 to 6 monocyclic alicyclic structures include 4,4′-dicyclohexylmethane diisocyanate (hydrogenated MDI);
Biuret and isocyanurate forms of 4,4′-dicyclohexylmethane diisocyanate (hydrogenated MDI);
Trimer adduct of trimethylolpropane (TMP) and hydrogenated MDI;
Biuret and isocyanurate forms of polyisocyanates such as isophorone diisocyanate, methylcyclohexylene diisocyanate (hydrogenated TDI), 1,3-bis (isocyanatomethyl) cyclohexane (hydrogenated m-XDI);
3 moles of any of polyisocyanates such as isophorone diisocyanate, methylcyclohexylene diisocyanate (hydrogenated TDI), and 1,3-bis (isocyanatomethyl) cyclohexane (hydrogenated m-XDI), and trimethylolpropane (TMP) Trimer adduct with 1 mole, etc .;
Examples include adducts of trimethylolpropane (TMP) with 2 mol of isophorone diisocyanate and 1 mol of hexamethylene diisocyanate (HDI).

Examples of the polyisocyanate having two monocyclic alicyclic structures include 4,4′-dicyclohexylmethane diisocyanate (hydrogenated MDI), trimethylolpropane (TMP) and 2 moles of isophorone diisocyanate, and hexamethylene diisocyanate (HDI). ) 1 mole of adduct, and 4,4′-dicyclohexylmethane diisocyanate (hydrogenated MDI) is preferred.

An aromatic ring means a ring having aromaticity, that is, a ring having a (4n + 2) π electron system (n is a natural number), and includes those containing heteroatoms. Examples of the aromatic ring include 5-membered rings such as a furan ring, a thiophene ring, a pyrrole ring, an imidazole ring, a thiazole ring, and an oxadiazole ring, and a 6-membered ring such as a benzene ring, a pyridine ring, and a pyrazine ring. A ring is preferable, and a benzene ring is more preferable.

The number of aromatic rings in one molecule in the polyisocyanate (a2) is preferably 3 to 7 and more preferably 3 because the electrical insulation of the cured product of the curable composition is improved.

Examples of the polyisocyanate having 3 to 7 monocyclic aromatic rings include 4,4 ′, 4 ″ -triphenylmethane triisocyanate;
1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, m-xylene diisocyanate, m-isocyanatophenylsulfonyl isocyanate, p-isocyanatophenylsulfonyl isocyanate 2,4′-diphenylmethane diisocyanate, 4,4′-diisocyanatobiphenyl, 3,3′-dimethyl-4,4′-diisocyanatobiphenyl, 3,3′-dimethyl-4,4′-diisocyanate Biuret and isocyanurate forms of polyisocyanates such as natodiphenylmethane;
1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, m-xylene diisocyanate, m-isocyanatophenylsulfonyl isocyanate, p-isocyanatophenylsulfonyl isocyanate 2,4′-diphenylmethane diisocyanate, 4,4′-diisocyanatobiphenyl, 3,3′-dimethyl-4,4′-diisocyanatobiphenyl, 3,3′-dimethyl-4,4′-diisocyanate Examples thereof include a trimer adduct of 3 mol of any one of polyisocyanates such as natodiphenylmethane and 1 mol of trimethylolpropane (TMP). In general, tolylene diisocyanate is a mixture of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate.

As polyisocyanate having three monocyclic aromatic rings,
4,4 ′, 4 ″ -triphenylmethane triisocyanate;
1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, m-xylene diisocyanate, m-isocyanatophenylsulfonyl isocyanate, p-isocyanatophenylsulfonyl isocyanate Biuret and isocyanurate forms of polyisocyanates such as
1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, m-xylene diisocyanate, m-isocyanatophenylsulfonyl isocyanate, p-isocyanatophenylsulfonyl isocyanate A trimer adduct of 3 mol of any one of polyisocyanates such as 1 and 1 mol of trimethylolpropane (TMP) is exemplified, and a trimer adduct of trimethylolpropane and tolylene diisocyanate is preferable.

The polyisocyanate used in the present invention is a polyisocyanate having one monocyclic or polycyclic alicyclic structure, in addition to the above polyisocyanate, within a range not impairing the object of the present invention. And / or a polyisocyanate having a polycyclic aromatic ring, an aliphatic polyisocyanate having no ring structure, and the like.

Examples of the polyisocyanate having one monocyclic or polycyclic alicyclic structure include isophorone diisocyanate, methylcyclohexylene diisocyanate (hydrogenated TDI), 2,5-norbornane diisocyanate, and 2,6-norbornane diisocyanate. .

Examples of the polyisocyanate having 2 or less monocyclic and / or polycyclic aromatic rings include 4,4′-diphenylmethane diisocyanate (MDI), 2,4′-diphenylmethane diisocyanate, 4,4′-diisocyanatobiphenyl, 3,3′-dimethyl-4,4′-diisocyanatobiphenyl, 3,3′-dimethyl-4,4′-diisocyanatodiphenylmethane, 1,5-naphthylene diisocyanate, 1,3-phenylene diisocyanate, 1, Examples include 4-phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, m-xylene diisocyanate, m-isocyanatophenylsulfonyl isocyanate, p-isocyanatophenylsulfonyl isocyanate.

Examples of the aliphatic polyisocyanate having no ring structure include ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, 1,6,11-undecane triisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2, Examples include 6-diisocyanatomethyl caproate, bis (2-isocyanatoethyl) fumarate, bis (2-isocyanatoethyl) carbonate, 2-isocyanatoethyl-2,6-diisocyanatohexanoate.

In addition, polyisocyanate (a2) may be used independently or 2 or more types may be used together. When two or more types are used in combination, any of polyisocyanates having an alicyclic structure, polyisocyanates having an aromatic ring, a combination of a polyisocyanate having an alicyclic structure and a polyisocyanate having an aromatic ring may be used. A combination of a polyisocyanate having an alicyclic structure and a polyisocyanate having an aromatic ring is preferable, and 4,4′-dicyclohexylmethane diisocyanate (hydrogenated MDI), a trimer adduct of trimethylolpropane and tolylene diisocyanate It is more preferable to use in combination.

When the polyisocyanate having an alicyclic structure and the polyisocyanate having an aromatic ring are used in combination, the polyisocyanate having an alicyclic structure and the polyisocyanate having an aromatic ring have an alicyclic structure with respect to 100 parts by mass in total. The polyisocyanate is preferably 1 to 40 parts by mass, and more preferably 1.5 to 30 parts by mass.

Since the polyisocyanate (a2) contains 2 to 6 monocyclic alicyclic structures or 3 to 7 monocyclic aromatic rings, the cured product of the curable composition has excellent electrical properties. It has excellent crack resistance even in portions that have insulating properties and insufficient photocuring.

In the polyisocyanate (a2), the total content of the polyisocyanate having 2 to 6 monocyclic alicyclic structures or 3 to 7 monocyclic aromatic rings in one molecule is 50% by mass or more. 60 mass% or more is more preferable, 70 mass% or more is more preferable, 80 mass% or more is further more preferable, 90 mass% or more is particularly preferable, and 100 mass% is most preferable. When the total content of polyisocyanates having 2 to 6 monocyclic alicyclic structures or 3 to 7 monocyclic aromatic rings in one molecule is 50% by mass or more, The cured product has excellent electrical insulation and excellent crack resistance even in a portion where photocuring is insufficient.

Urethane resin (A) is a polymer of a monomer containing alcohol (a1) and polyisocyanate (a2) containing polyol (a1-1) as essential components. In the monomer used as the raw material of the urethane resin (A), the equivalent ratio of the isocyanate group in the polyisocyanate (a2) to the hydroxyl group in the alcohol (a1) (isocyanate group / hydroxyl group) is greater than 1 and 8 or less. Yes, greater than 1 and preferably 7 or less, more preferably greater than 1 and 6 or less. When the equivalent ratio (isocyanate group / hydroxyl group) is 8 or less, since the urethane resin (A) has a sufficient molecular weight, the cured product of the curable composition has excellent electrical insulation and light. Excellent crack resistance even in areas where curing is insufficient. The equivalent ratio (isocyanate group / hydroxyl group) needs to be larger than 1 because the urethane resin (A) has moisture curability, and the storage stability of the curable composition is improved. 2.5 or more is more preferable.

In addition, the equivalent ratio (isocyanate group / hydroxyl group) of the isocyanate group in the polyisocyanate (a2) to the hydroxyl group in the alcohol (a1) is the number of hydroxyl groups in the alcohol (a1) by the number of isocyanate groups in the polyisocyanate (a2). Divide and seek.

The number of hydroxyl groups in the alcohol (a1) is calculated based on the following formula. The hydroxyl value was measured according to JIS K 1557-1: 2007 (ISO 14900: 2001) “Plastics—Polyurethane raw material polyol test method—Part 1: Determination of hydroxyl value”, method B. This is the value obtained.
Number of hydroxyl groups in alcohol (a1) = content of alcohol (a1) in monomer as raw material × hydroxyl value / 56100

The number of isocyanate groups in the polyisocyanate (a2) is calculated based on the following formula. The isocyanate equivalent refers to a value obtained by dividing the molecular weight of polyisocyanate by the number of isocyanate groups in one molecule. Specifically, it means a value measured according to JIS K1603.
Number of isocyanate groups in polyisocyanate (a2) = content of polyisocyanate (a2) in monomer as raw material / isocyanate equivalent

The weight average molecular weight of the urethane resin (A) is preferably from 5,000 to 100,000, more preferably from 5,000 to 50,000, particularly preferably from 10,000 to 25,000. When the weight average molecular weight of the urethane resin (A) is 5000 or more, the electrical insulation and crack resistance of the cured product of the curable composition are improved. When the weight average molecular weight of the urethane resin (A) is 100,000 or less, the curable composition has a low viscosity and the handleability is improved.

The weight average molecular weight of the urethane resin (A) refers to a value obtained by converting the molecular weight measured by gel permeation chromatography (GPC) into polystyrene. For example, it can be measured under the following measurement conditions.
Equipment: HLC-8220GP manufactured by Tosoh Corporation
Column: product name “TSKgel SuperHZM-H” manufactured by Tosoh Corporation Column temperature: 40 ° C.
Eluent: Tetrahydrofuran Detection: RI
Standard polystyrene for calibration curve: Trade name “TSKgel standard polystyrene” manufactured by Tosoh Corporation

The content of the polyisocyanate (a2) component in the urethane resin (A) is preferably 1 to 99% by mass, more preferably 5 to 80% by mass, and particularly preferably 15 to 70% by mass.

The urethane resin (A) may be produced using a known polymerization method. Specifically, an alcohol (a1) and a polyisocyanate (a2) containing a polyol (a1-1) and, if necessary, a hydroxyl group-containing (meth) acrylate (a1-2) are converted into a polyisocyanate for the hydroxyl group in the alcohol (a1). The urethane resin (A) can be produced by polymerizing a monomer as a raw material to be contained so that the equivalent ratio of isocyanate groups (isocyanate group / hydroxyl group) in (a2) is in the above-described range by a known polymerization method. it can. The polymerization of the urethane resin (A) may be performed in a monofunctional alkyl (meth) acrylate described later.

More specifically, after supplying the monofunctional alkyl (meth) acrylate into the reaction vessel and supplying the polyisocyanate (a2), the alcohol (a1) from which moisture has been removed is batched or divided into the reaction vessel. The urethane resin (A) can be produced by reacting with the polyisocyanate (a2) until the hydroxyl group of the alcohol (a1) is substantially eliminated.

The polymerization of the urethane resin (A) is preferably performed at 10 to 120 ° C. for 0.5 to 10 hours.

The polymerization reaction of the urethane resin (A) may be performed in the presence of a urethanization catalyst as necessary. Examples of the urethanization catalyst include organometallic compounds such as dibutyltin oxide, tin 2-ethylcaproate, tin octylate, and dibutyltin dilaurate.

The content of the urethane resin (A) in the curable composition is when the total amount of the urethane resin (A), the monofunctional alkyl (meth) acrylate (B) and the photopolymerization initiator (C) is 100% by mass. 15 to 60% by mass, preferably 30 to 60% by mass, more preferably 35 to 50% by mass, and particularly preferably 40 to 48% by mass. When the content of the urethane resin (A) is 15% by mass or more, the cured product of the curable composition has excellent electrical insulation and excellent crack resistance even in a portion where photocuring is insufficient. Have. When the content of the urethane resin (A) is 60% by mass or less, the curable composition has a low viscosity and the handleability is improved.

[Monofunctional (meth) acrylate]
The curable composition contains a monofunctional (meth) acrylate (B) that does not contain a ring structure and has an alkyl group having 10 or less carbon atoms. Monofunctional means having only one radical polymerizable unsaturated bond in one molecule. The alkyl group is a remaining atomic group obtained by removing one hydrogen atom from an aliphatic saturated hydrocarbon, represented by —C _n H _{2n + 1} , and does not include heteroatoms such as nitrogen and sulfur. The ring structure includes all cyclic structures formed by carbon and other atoms (nitrogen, sulfur, etc.).

Since it contains a monofunctional (meth) acrylate (B) that does not contain a ring structure and has an alkyl group having 10 or less carbon atoms, the cured product of the curable composition has excellent electrical insulation. In addition, it has excellent crack resistance even in a portion where photocuring is insufficient, and the curable composition has excellent moisture curability.

Monofunctional (meth) acrylate (B) preferably does not contain a functional group that reacts with an isocyanate group. Examples of the functional group that reacts with the isocyanate group include a hydroxyl group, an amino group, a thiol group, and a carboxyl group.

The alkyl group of the monofunctional (meth) acrylate (B) has 10 or less carbon atoms, preferably 2 to 10, more preferably 4 to 9, and particularly preferably 6 to 9. When the carbon number of the alkyl group is 10 or less, the cured product of the curable composition has excellent electrical insulation and excellent crack resistance even in a portion where photocuring is insufficient, The moisture curability of the curable composition is improved. The odor from a curable composition can be suppressed as carbon number of an alkyl group is 2 or more.

Examples of the monofunctional (meth) acrylate (B) include alkyl (meta) such as n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-butyl (meth) acrylate, and n-octyl (meth) acrylate. ) Alkyl (meth) acrylates such as acrylate, alkyl (meth) acrylate is preferred, and alkyl acrylate is more preferred. Further, n-octyl (meth) acrylate is preferable, and n-octyl acrylate is more preferable. In addition, monofunctional (meth) acrylate may be used independently or 2 or more types may be used together.

The content of the monofunctional (meth) acrylate (B) in the curable composition is 100 masses of the total amount of the urethane resin (A), the monofunctional alkyl (meth) acrylate (B) and the photopolymerization initiator (C). % Is preferably 30 to 70% by mass, more preferably 40 to 65% by mass, and particularly preferably 45 to 60% by mass. When the content of the monofunctional (meth) acrylate (B) is 30% by mass or more, the photocurability of the curable composition is improved and the cured product of the curable composition has excellent crack resistance. When the content of the monofunctional (meth) acrylate (B) is 70% by mass or less, a cured product having excellent electrical insulation and crack resistance can be obtained even in a portion where photocuring is insufficient.

[Multifunctional (meth) acrylate (D)]
The curable composition may contain a polyfunctional (meth) acrylate (D). By containing polyfunctional (meth) acrylate (D), the electrical insulation of the hardened | cured material of a curable composition improves. Polyfunctional means having two or more radically polymerizable unsaturated bonds in one molecule.

The polyfunctional (meth) acrylate (D) preferably does not contain a functional group that reacts with an isocyanate group. Examples of the functional group that reacts with the isocyanate group include a hydroxyl group, an amino group, a thiol group, and a carboxyl group.

The polyfunctional (meth) acrylate (D) is not particularly limited. For example, 1,3-butylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di Alkylene glycol di (meth) acrylates such as (meth) acrylate, ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, neopentyl glycol di (meth) diacrylate, triethylene glycol di (meth) acrylate, tri Polyoxyalkylene glycol di (meth) acrylate such as propylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, bisphenol A or hydrogenated Examples include diacrylates of adducts of alkylene oxide of Sphenol A, trimethylolpropane tri (meth) acrylate, pentaerythritol tetraacrylate, ditrimethylol tetraacrylate, dipentaerythritol hexaacrylate, etc., and alkylene glycol di (meth) acrylate is 1,3-butylene glycol di (meth) acrylate is more preferable, and 1,3-butylene glycol diacrylate is particularly preferable. Polyfunctional (meth) acrylate may be used independently or 2 or more types may be used together.

The content of the polyfunctional (meth) acrylate (D) in the curable composition is preferably 15% by mass or less based on the total amount of the monofunctional (meth) acrylate (B) and the polyfunctional (meth) acrylate (D). 10 mass% or less is more preferable, and 6.5 mass% or less is especially preferable. When the content of the polyfunctional (meth) acrylate is 15% by mass or less, the cured product of the curable composition has excellent electrical insulation and excellent crack resistance even in a portion where photocuring is insufficient. Furthermore, the moisture curability of the curable composition is improved.

[Photopolymerization initiator (C)]
The curable composition contains a photopolymerization initiator (C). The photopolymerization initiator is particularly limited as long as it can be decomposed by irradiating active energy rays such as ultraviolet rays and electron beams to generate radicals and initiate the photocuring reaction of the curable composition. Not.

The photopolymerization initiator (C) is not particularly limited, and examples thereof include benzoin, benzoin ethyl ether, benzophenone, acylphosphine oxide; and alkylphenones such as 2,2-dimethoxy-1,2-diphenylethane-1-one. Compound; 2-methyl-1 [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one And α-aminoalkylphenone compounds such as 2-dimethylamino-2- (4-methyl-benzyl) -1- (4-morpholin-4-yl-phenyl) -butan-1-one; benzophenone, 2-methyl Benzophenone, 3-methylbenzophenone, 4-methylbenzophenone, 2,4,6-trimethylbenzo Phenone, 4-phenylbenzophenone, 4- (methylphenylthio) phenylphenylmethane, methyl-2-benzophenone, 1- [4- (4-benzoylphenylsulfanyl) phenyl] -2-methyl-2- (4-methylphenyl) Sulphonyl) propan-1-one, 4,4′-bis (dimethylamino) benzophenone, 4,4′-bis (diethylamino) benzophenone, N, N′-tetramethyl-4,4′-diaminobenzophenone, N, N ′ Benzophenone compounds such as tetraethyl-4,4'-diaminobenzophenone and 4-methoxy-4'-dimethylaminobenzophenone; bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide and 2,4,6-trimethyl Benzoyl-diphenyl-phosphie Acylphosphine oxide compounds such as oxides; Oxyphenylacetic acid; Phenylglyoxylic acid ester compounds such as phenylglyoxylic acid methyl ester; Bis (η5-2,4-cyclopentadien-1-yl) -bis (2,6 -Titanocene compounds such as -difluoro-3- (1H-pyrrol-1-yl) -phenyl) titanium; 1,2-octanedione, 1- [4- (phenylthio)-, 2- (O-benzoyloxime) and ethanone Oxime ester compounds such as 1- [9- (ethyl) -6- (2-methylbenzoyl) -9H-carbazol-3-yl]-, 1- (O-acetyloxime).

Photopolymerization initiators (C) are, for example, trade names “Irgacure 184”, “Irgacure 907”, “Irgacure 819”, “Irgacure TPO”, “Irgacure 651”, “Irgacure 369”, “Irgacure” manufactured by BASF Japan. 379 ”,“ Irgacure 379EG ”,“ Irgacure MBF ”,“ Irgacure 784 ”,“ Irgacure OXE01 ”and“ Irgacure OXE02 ”. In addition, a photoinitiator (C) may be used independently or 2 or more types may be used together.

The content of the photopolymerization initiator (C) in the curable composition is 100% by mass of the total amount of the urethane resin (A), the monofunctional alkyl (meth) acrylate (B) and the photopolymerization initiator (C). 1 to 15% by mass is preferable, 2 to 8% by mass is more preferable, and 3 to 7% by mass is particularly preferable. The photocurability of a curable composition improves that content of a photoinitiator (C) is 1 mass% or more. When the content of the photopolymerization initiator (C) is 10% by mass or less, the cured product of the curable composition has excellent electrical insulation and crack resistance.

[Other ingredients]
The curable composition comprises a urethane resin (A), a monofunctional (meth) acrylate (B) and a photopolymerization initiator (C) as essential components, but if necessary, a moisture curing catalyst (F), polymerization An inhibitor, an antioxidant, an antifoaming agent, a leveling agent, an additive such as a silane coupling agent and a metal deactivator, and a solvent may be contained.

The moisture curing catalyst (F) is not particularly limited, and examples thereof include organometallic compounds and tertiary amine compounds. Examples of the organic metal compound include organic tin compounds such as dibutyltin dilaurate, organic iron compounds, organic zinc compounds, organic titanium compounds, organic aluminum compounds, organic zirconium compounds, and organic bismuth compounds. In addition, a moisture hardening catalyst (F) may be used independently, or 2 or more types may be used together. The blending ratio of the moisture curing catalyst (F) is not particularly limited, and may be appropriately adjusted according to the purpose and application. The moisture effect catalyst (F) may be used for the synthesis of the urethane resin (A) as a urethanization catalyst.

Examples of the organic tin compound include tin carboxylates such as dibutyltin dilaurate, dibutyltin maleate, dibutyltin diacetate, dibutyltin diacetoacetonate, tin octylate, tin naphthenate, tin laurate and tin felzatic acid. And a reaction product of dibutyltin oxide and phthalate.

Examples of the organic iron compound include tris (acetylacetonato) iron, tris (2,2,6,6-tetramethyl-3,5-heptanedionate) iron, tris (tetrafluoroacetylacetonato) iron, chloride Examples thereof include ferric iron, tris (2-ethylhexanoic acid) iron, iron naphthenate, triethoxy iron, and triisopropoxy iron.

Examples of the organic zinc compound include bis (acetylacetonato) zinc, bis (2,2,6,6-tetramethyl-3,5-heptanedionate) zinc, bis (tetrafluoroacetylacetonato) zinc, bis (2-ethylhexanoic acid) zinc, zinc naphthenate, diethoxy zinc, diisopropoxy zinc and the like can be mentioned.

Examples of the organic titanium compound include titanic acid esters such as tetrabutyl titanate and tetrapropyl titanate, and titanium chelate compounds such as titanium tetraacetylacetonate.

Examples of the organoaluminum compound include aluminum trisacetylacetonate, aluminum trisethylacetoacetate, diisopropoxyaluminum ethylacetoacetate, and the like.

Examples of the organic zirconium compound include zirconium chelate compounds such as zirconium tetraacetylacetonate.

Examples of the organic bismuth compound include bismuth-tris (neodecanoate), bismuth-tris (2-ethylhexoate), and bismuth octylate.

Examples of tertiary amine compounds include trialkylamines such as triethylamine; tetraalkylalkylenediamines such as tetramethylethylenediamine and tetramethylhexanediamine; pentaalkyldialkylenetriamines such as pentamethyldiethylenetriamine; trimethylaminoethylpiperazine and dimethylpiperazine Piperazines; N-alkylimidazoles such as 1,2-dimethylimidazole; bis (dimethylaminoethyl) ether; triethylenediamine [1,4-diazabicyclo [2,2,2] octane (DABCO)]; N-methylmorpholine; Examples include 1,8-diazabicyclo [5,4,0] undecene-7 (DBU) and 2,4,6-tris (dimethylaminomethyl) phenol.

Examples of the polymerization inhibitor include hydroquinone, hydroquinone monomethyl ether, benzoquinone, pt-butylcatechol and 2,6-di-t-butyl-4-methylphenol. In addition, a polymerization inhibitor may be used independently or 2 or more types may be used together. The blending ratio of the polymerization inhibitor is not particularly limited, and may be appropriately adjusted according to the purpose and application.

Examples of the antioxidant include a phenol-based antioxidant, a phosphorus-based antioxidant, and a sulfur-based antioxidant. In addition, an antioxidant may be used independently or 2 or more types may be used together. The mixing ratio of the antioxidant is not particularly limited, and may be appropriately adjusted according to the purpose and application. The phenolic antioxidants are, for example, trade names “Adeka Stub AO-20”, “Adeka Stub AO-60” and “Adeka Stub AO-80” from Adeka, and trade names “Irganox 1010” and “Irganox 1076” from BASF Japan. , "Irganox 1135" and "Irganox 1520L". Phosphorous antioxidants are commercially available, for example, from Adeka under the trade names “Adekastab PEP-4C” and “Adekastab 2112”, and from BASF Japan under the trade name “Irgafos 168”. Sulfur-based antioxidants are commercially available, for example, from Adeka under the trade names “Adekastab AO-412S” and “Adekastab AO-503”, and from BASF Japan under the trade names “Irganox PS 800 FL” and “Irganox PS 802 FL” Has been.

Antifoaming agents are, for example, trade names “BYK-054”, “BYK-057”, “BYK-065”, “BYK-066N”, “BYK-067A” and “BYK-1794” from BYK Japan Trade names “TEGO Airex 904W”, “TEGO Airex 910”, “TEGO Airex 920”, “TEGO Airex 931”, “TEGO Airex 945”, “TEGO Foamex 833” and “TEGO Foamex 833T” and “TEGO Fairex 833T” are available from Evonik. ing. In addition, an antifoamer may be used independently or 2 or more types may be used together. The mixing ratio of the antifoaming agent is not particularly limited, and may be appropriately adjusted according to the purpose and application.

Examples of leveling agents include silicone leveling agents, acrylic leveling agents, and fluorine leveling agents. In addition, a leveling agent may be used independently or 2 or more types may be used together. The mixing ratio of the leveling agent is not particularly limited, and may be appropriately adjusted according to the purpose and application. Examples of the silicone leveling agent include trade names “BYK-300”, “BYK-302”, “BYK-307”, “BYK-320”, “BYK-322”, “BYK-325” from BYK Japan. ”,“ BYK-330 ”,“ BYK-331 ”,“ BYK-333 ”,“ BYK-345 ”,“ BYK-370 ”,“ BYK-377 ”,“ BYK-378 ”,“ BYK-3455 ”, “BYK-UV3500” and “BYK-UV3510”, trade names “TEGO Flow 425”, “TEGO Glide 100”, “TEGO Glide 110” and “TEGO Glide 432” from Evonik, and trade names “Togo Dow Corning” "Dow Corning 56 Additive" and "Dow C It is commercially available in the rning 57 Additive ". Acrylic leveling agents are, for example, trade names “BYK-350”, “BYK-354”, “BYK-356” and “BYK-3441” from Big Chemie Japan, and trade names “TEGO Flow 370” and Evonik. It is commercially available from “TEGO Flow ZFS 460”. Fluorine-based leveling agents include, for example, trade names “Novec FC-4430” and “Novec FC-4432” from Sumitomo 3M, and trade names “Fategent 251”, “Factent FTX-218” and “Futter” from Neos. It is commercially available at “Gent 710FL” and “Fargent 601AD”.

Silane coupling agents are commercially available, for example, from Shin-Etsu Silicone under the trade names “KBM-1003”, “KBE-1003”, “KBM-503”, “KBM-5103” and “KBE-9007”. In addition, a silane coupling agent may be used independently or 2 or more types may be used together. The blending ratio of the silane coupling agent is not particularly limited, and may be appropriately adjusted according to the purpose and application.

Metal deactivators are, for example, trade names “Adekastab CDA-1”, “Adekastab CDA-1M”, “Adekastab CDA-6” and “Adekastab CDA-10” from Adeka, and “Irganox MD1024” from BASF Japan. These are commercially available from Johoku Chemical Industry Co., Ltd. under the trade names “BT-120”, “BT-LX”, and “TT-LX”.

Examples of the solvent include hydrocarbons such as pentane, hexane, heptane, and cyclohexane, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone, and esters such as ethyl acetate and butyl acetate. In addition, a solvent may be used independently or 2 or more types may be used together.

The curable composition can be produced by stirring and mixing the urethane resin (A), the monofunctional (meth) acrylate (B), the photopolymerization initiator (C), and other additives using a general-purpose stirrer. it can.

The curable composition can be used, for example, as a conformal coating agent, and specifically, electrically insulates the electronic circuit board after soldering in order to protect the electronic circuit board from water, moisture and dust. Used for processing.

Specifically, the curable composition is applied onto the electronic component of the electronic circuit board formed by soldering the electronic component on the substrate, and the electronic component is covered with the curable composition.

By irradiating the curable composition with active energy rays (for example, ultraviolet rays, electron beams, etc.), a monofunctional (meth) acrylate, and a polyfunctional (meth) acrylate and a urethane resin (optionally contained) The hydroxyl group-containing (meth) acrylate component A) undergoes a radical polymerization reaction and is photocured. Simultaneously with this photocuring and after irradiation with active energy rays, the curable composition produces a cured product by moisture curing by causing the isocyanate group of the urethane resin (A) to react with moisture in the air. To do.

The cured product thus produced has excellent electrical insulation, and has sufficient crack resistance even in a portion where the active energy ray is not irradiated or a portion where irradiation is insufficient, Furthermore, the cured product has excellent appearance (transparency). Therefore, the cured product of the curable composition stably protects the electronic component from contaminants such as water, dust and metal powder over a long period of time while maintaining the electrical insulation state. And since the cured product of the curable composition is excellent in transparency, the state of the electronic component can be easily seen through the cured product even after coating and protection, and maintenance of the electronic circuit board can be performed. It can be done easily.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the examples.

The compounds used for preparing the curable composition are shown below. For products containing a solvent, the type of solvent and the solid content of the compound are shown.

[Polyol (a1-1)]
・ Hydrogenated polybutadiene diol 1 (trade name “GI-3000” manufactured by Nippon Soda Co., Ltd.), number average molecular weight: 3000, iodine value: 21 or less ・ Hydrogenated polybutadiene diol 2 (trade name “GI-2000 manufactured by Nippon Soda Co., Ltd.”) ], Number average molecular weight: 2100, iodine value: 21 or less, hydrogenated polyisoprene diol (trade name “EPOL” manufactured by Idemitsu Kosan Co., Ltd.), number average molecular weight: 2500, iodine value: 7.9
・ Polycarbonatediol 1 (trade name “Duranol T5652” manufactured by Asahi Kasei Chemicals)
・ Polycarbonate diol 2 (trade name “PLACCEL CD220PL” manufactured by Daicel Corporation)
・ Polyester polyol (Kuraray Polyol P-1010)
・ Acrylic polyol (trade name “ARUFON UH-2000” manufactured by Toagosei Co., Ltd.)

[Polyisocyanate (a2)]
Trimeryl adduct of trimethylolpropane and tolylene diisocyanate (TMP-TDI) (trade name “Coronate L”, ethyl acetate, solid content: 75% by mass, manufactured by Tosoh Corporation), aromatic ring: 3 '-Dicyclohexylmethane diisocyanate (hydrogenated MDI) (trade name “Desmodur W” manufactured by Sumika Covestrourethane Co., Ltd.), cycloaliphatic structure: 2 • isocyanurate of tolylene diisocyanate (TDI / isocyanurate) (Sumika) Covestrourethane product name “Desmodur IL 1451”, butyl acetate, solid content: 51% by mass, aromatic ring: 3, 1,3-bis (isocyanatomethyl) cyclohexane (hydrogenated m-XDI) (Mitsui Chemicals) Name “Takenate 600”), cycloaliphatic structure: 1 isocyanurate of hexamethylene diisocyanate (HDI / isocyanurate) (Asahi) Product name “Duranate MHG-80B”, butyl acetate, solid content: 80% by mass), alicyclic structure and aromatic ring: 0 pieces, hexamethylene diisocyanate prepolymer (HDI / prepolymer) (Asahi Kasei Chemicals) Product name “Duranate D201”), alicyclic structure and aromatic ring: 0

[Hydroxyl group-containing acrylate (a1-2)]
・ Pentaerythritol triacrylate (PETA) (trade name “Aronix M-306” manufactured by Toagosei Co., Ltd.)

[Urethane acrylate]
-Urethane acrylate (trade name “TEAI-1000” manufactured by Nippon Soda Co., Ltd.), a hydrogenated butadiene skeleton in the main chain, a urethane bond, and an acryloyl group at both ends, number average molecular weight: 2000

[Polyisocyanate (E)]
-Trimethylolpropane and tolylene diisocyanate trimer adduct (TMP-TDI) (trade name "Coronate L" manufactured by Tosoh Corporation), 3 aromatic rings-Trimethylolpropane and tolylene diisocyanate trimer adduct (TMP-TDI) (trade name “Coronate L” manufactured by Tosoh Corporation) and reaction product of pentaerythritol triacrylate (trade name “Aronix M-306” manufactured by Toagosei Co., Ltd.)

[Monofunctional acrylate (B)]
N-octyl acrylate (trade name “NOAA”, manufactured by Osaka Organic Chemical Industry Co., Ltd.), glass transition temperature: −65 ° C.
・ Lauryl acrylate (trade name “LA”, manufactured by Osaka Organic Chemical Industry Co., Ltd.), glass transition temperature: −23 ° C.
・ Isobonyl acrylate (trade name “IBXA” manufactured by Osaka Organic Chemical Industry Co., Ltd.), glass transition temperature: 97 ° C.

[Polyfunctional acrylate (D)]
1,3-butylene glycol diacrylate (trade name “SR212B” manufactured by Sartomer), glass transition temperature: 101 ° C.

[Photopolymerization initiator (C)]
・ Bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (trade name “Irgacure 819” manufactured by BASF)

[Moisture curing catalyst (F), urethanization catalyst]
・ Dibutyltin dilaurate (DBTDL) (trade name “TN-12” manufactured by Sakai Chemical Industry Co., Ltd.)

(Synthesis Examples 1 to 10, Comparative Synthesis Examples 1 to 11)
In the reaction vessel, polyol (a1-1), polyisocyanate (a2), hydroxyl group-containing acrylate (a1-2), monofunctional acrylate (B), polyfunctional acrylate (D) and 4-methoxyphenol (polymerization inhibitor) After supplying a predetermined amount shown in Tables 1 to 4 by the trade name “MQ” manufactured by Kawaguchi Chemical Industry Co., Ltd., the inside of the reaction vessel was heated to 60 ° C. while bubbling and stirring with dry air. In addition, the equivalent ratio (isocyanate group / hydroxyl group) of the isocyanate group in the polyisocyanate (a2) to the hydroxyl group in the alcohol (a1) is described in the column of “equivalent ratio (isocyanate group / hydroxyl group)”. The numerical values in Tables 1 to 4 are numerical values in terms of solid content excluding the solvent.

The monofunctional acrylate (B) and the polyfunctional acrylate (D) are used as a reaction solvent, and a part of the monofunctional acrylate (B) and the polyfunctional acrylate (D) blended in the curable composition is a urethane resin ( It was added to the reaction system during the preparation of A).

Thereafter, the urethane resin (A) was obtained by adding a predetermined amount of dibutyltin dilaurate as a urethanization catalyst shown in Tables 1 to 4 and maintaining for 3 hours. The weight average molecular weights of the obtained urethane resin (A) are shown in Tables 1 to 4.

(Synthesis of polyisocyanate (E) used in Comparative Example 13)
Polyisocyanate [Trimer adduct of trimethylolpropane and tolylene diisocyanate (TMP-TDI)] (trade name “Coronate L” manufactured by Tosoh Corporation) 59.8 parts by mass (in terms of solid content), pentaerythritol triacrylate (PETA ) (Trade name “Aronix M-306” manufactured by Toagosei Co., Ltd.) 40.2 parts by mass, 0.01 parts by mass of dibutyltin dilaurate (DBTDL), n-octyl acrylate (trade name “NOAA” manufactured by Osaka Organic Chemical Industry Co., Ltd.) 80.1 parts by mass and 0.1 part by mass of 4-methoxyphenol (trade name “MQ”, manufactured by Kawaguchi Chemical Industries) as a polymerization inhibitor were mixed by stirring and dissolved, and heated at 60 ° C. for 2 hours to obtain an acryloyl group. A containing polyisocyanate was obtained.

(Examples 1 to 10, Comparative Examples 1 to 11)
Dibutyltin dilaurate as the above-mentioned urethane resin (A), monofunctional acrylate (B), photopolymerization initiator (C), polyfunctional acrylate (D), and moisture curing catalyst (F) as shown in Tables 5 to 8 in predetermined planets. The curable composition was obtained by supplying to a stirrer and stirring and mixing uniformly. The urethane resin (A) used was listed in the column of the type of urethane resin (A) in Tables 5-8.

The urethane resin (A) produced above contains a monofunctional acrylate (B) or a polyfunctional acrylate (D), but the values in the columns of the urethane-based resins (A) shown in Tables 5 to 8 are as follows. , The amount excluding the monofunctional acrylate (B) and the polyfunctional acrylate (D). The values in the columns of the monofunctional acrylate (B) and the polyfunctional acrylate (D) shown in Tables 5 to 8 are the monofunctional acrylate (B) and the polyfunctional acrylate (D) added when the urethane resin (A) was produced, respectively. It is the value including each amount of each, and is the total amount of each of the monofunctional acrylate (B) and the polyfunctional acrylate (D) contained in the curable composition. The numerical values in Tables 5 to 8 are all in terms of solid content excluding the solvent.

(Comparative Examples 12 and 13)
Urethane acrylate, polyisocyanate (E), monofunctional acrylate (B), photopolymerization initiator (C), polyfunctional acrylate (D) and dibutyltin dilaurate as moisture-curing catalyst (F) as shown in Table 8 in predetermined planets. The curable composition was obtained by supplying to a stirrer and stirring and mixing uniformly.

The resulting curable composition was measured for electrical insulation, crack resistance, appearance and moisture curability in the following manner, and the results are shown in Tables 5-8.

(Electrical insulation)
A curable composition was applied at a film thickness of 50 μm on a JIS 2 type comb substrate to prepare two test pieces. The curable composition of one test piece is irradiated with ultraviolet rays having an emission wavelength of 365 nm to photocure the curable composition, and then the test piece is left to stand in an atmosphere of 23 ° C. and 50% relative humidity for 12 hours to be cured. The cured composition was moisture cured to produce a cured product.

The other test piece was left to stand in an atmosphere of 23 ° C. and 50% relative humidity for 12 hours without irradiating ultraviolet rays, and the curable composition was moisture-cured to produce a cured product.

After putting two test pieces in a thermo-hygrostat kept at 85 ° C. and a relative humidity of 85%, the applied voltage was set to 32 V, and the resistance value of the cured product after 96 hours was measured.

The resistance value of the cured product of the test piece that was irradiated with ultraviolet rays was written in the column “UV part”, and the resistance value of the cured product of the test piece that was not irradiated with ultraviolet rays was written in the column “dark part”.

(Crack resistance)
A reflow flux was applied to a glass epoxy substrate, and a chip resistor was soldered. Next, a curable composition was applied onto the chip resistance, and the chip resistance was coated with the curable composition to prepare two test pieces.

The curable composition of one test piece is irradiated with ultraviolet rays having an emission wavelength of 365 nm to photocure the curable composition, and then the test piece is left to stand in an atmosphere of 23 ° C. and 50% relative humidity for 12 hours to be cured. The cured composition was moisture cured to produce a cured product.

After holding the test piece at 125 ° C. for 30 minutes, the test piece was held at −40 ° C. for 30 minutes for a cycle of one cycle. The number of cycles performed was counted. Evaluation was made according to the following criteria.

The cycle number of the test piece irradiated with ultraviolet rays is described in the “UV part” column, and the cycle number of the test piece not irradiated with ultraviolet rays is described in the “dark part” column.

A ++: The number of cycles was 2000 or more.
A +: The number of cycles was 1500 or more and less than 2000.
A: The number of cycles was 1000 or more and less than 1500.
B: The number of cycles was 720 or more and less than 1000.
C: The number of cycles was 360 or more and less than 720.
D: The number of cycles was less than 360.

(Appearance)
The curable composition was applied to a glass plate with a film thickness of 50 μm. The curable composition was photocured by irradiating the curable composition with ultraviolet rays having an emission wavelength of 365 nm. The HAZE value of the cured product of the curable composition was measured using a haze meter (trade name “NDH 5000” manufactured by Nippon Denshoku Industries Co., Ltd.). The glass plate was subtracted as the background. It shows that transparency of cured | curing material is so high that a HAZE value is small. Evaluation was made based on the following criteria.

A +: The HAZE value was 0 or more and less than 0.25.
A: The HAZE value was 0.25 or more and less than 0.5.
B: The HAZE value was 0.5 or more and less than 1.0.
C: The HAZE value was 1.0 or more and less than 2.0.
D: The HAZE value was 2.0 or more.

(Moisture curable)
The curable composition was applied to a glass epoxy substrate with a film thickness of 50 μm, and was allowed to stand in a light-shielding environment at 23 ° C. and a relative humidity of 50% with the curable composition application surface being horizontal. The glass epoxy substrate is held so that the coating surface of the curable composition is vertical at 6 hours, 12 hours, and 24 hours after the application is completed, and the curable composition does not sag. The following evaluation was made based on the time required for the curable composition not to sag.
A: It was less than 6 hours.
B: 6 hours or more and less than 12 hours.
C: 12 hours or more and less than 24 hours.
D: The curable composition sagged at the time point of 24 hours.

The curable composition of the present invention can be suitably used for electrical insulation treatment for protecting a soldered electronic circuit board from water, moisture, dust and the like.

(Cross-reference of related applications)
This application claims priority based on Japanese Patent Application No. 2016-69988 filed on Mar. 31, 2016, the disclosure of which is incorporated herein by reference in its entirety. .

Claims

An alcohol (a1) containing a hydrogenated butadiene-based skeleton and / or a hydrogenated isoprene-based skeleton and containing a hydrogenated polybutadiene polyol and / or a hydrogenated polyisoprene polyol (a1-1); A polymer containing a polyisocyanate (a2) as a monomer component, the polymer containing the alcohol (a1) and the polyisocyanate (a2), and the polyisocyanate (a2) in the polyisocyanate (a2) with respect to the hydroxyl group in the alcohol (a1) A polymer of a monomer having an isocyanate group equivalent ratio (isocyanate group / hydroxyl group) of greater than 1 and 8 or less. The polyisocyanate (a2) comprises 2 to 6 monocyclic alicyclic rings in one molecule. Urethanes comprising a polyisocyanate having the formula structure or 3-7 monocyclic aromatic rings And fat (A),
A monofunctional (meth) acrylate (B) having no ring structure and having an alkyl group having 10 or less carbon atoms;
A curable composition comprising a photopolymerization initiator (C).
The curable composition according to claim 1, wherein the urethane resin (A) further contains a hydroxyl group-containing (meth) acrylate (a1-2) as a monomer component.
The polyisocyanate (a2) contains 4,4'-dicyclohexylmethane diisocyanate and / or a trimer adduct of trimethylolpropane and tolylene diisocyanate. The curable composition according to item 1.
The polyfunctional (meth) acrylate (D) is further included, and the content of the polyfunctional (meth) acrylate (D) in the total amount of the monofunctional alkyl (meth) acrylate (B) and the polyfunctional (meth) acrylate (D) is The curable composition according to any one of claims 1 to 3, wherein the content is 15% by mass or less.
The curable composition according to any one of claims 1 to 4, wherein the urethane resin (A) has a weight average molecular weight of 5,000 to 100,000.
A conformal coating agent comprising the curable composition according to any one of claims 1 to 5.
A cured product, which is a cured product of the curable composition according to any one of claims 1 to 5.