JP2021091871A - Curable resin composition - Google Patents

Abstract

To provide a curable resin composition that contains a monofunctional (meth)acrylate monomer but can relatively prevent a cured body from suffering from a phase separation, and can relatively prevent the cured body from emitting an odor.SOLUTION: A curable resin composition contains a curable compound having a branched polyolefin structure and a (meth)acryloyl group and an isocyanate group in the molecule, a tackifier, and a saturated straight-chain (meth)acrylate. The tackifier comprises a hydrocarbon resin having a constitutional unit of α-methyl styrene or a constitutional unit of its hydrogenated body in the molecule.SELECTED DRAWING: None

Description

The present invention relates to a curable resin composition. Specifically, the present invention relates to a curable resin composition that is cured by a curing treatment such as light irradiation.

Conventionally, in order to prevent a short circuit in an electronic circuit in an electronic component when moisture enters the electronic component, the surface of the electronic circuit is coated with a curable resin composition, and then the curable resin composition is used. It is known that the curable resin composition is cured by performing a curing treatment such as light irradiation (for example, irradiation with ultraviolet rays) (for example, Patent Document 1).

As such a curable resin composition, Patent Document 1 describes a (meth) acrylate oligomer containing a (meth) acryloyl group in the molecule, which is polymerized by irradiation with ultraviolet rays, and two or more isocyanate groups in the molecule. Those containing the low molecular weight isocyanate compound contained are disclosed.

Japanese Unexamined Patent Publication No. 2014-201593

By the way, in order to adjust the physical properties of the curable resin composition as described in Patent Document 1 (for example, to adjust the strength of the cured product obtained by curing the curable resin composition). , The curable resin composition may contain a monofunctional (meth) acrylate monomer.

However, when the monofunctional (meth) acrylate is contained in the curable resin composition, the (meth) acrylate oligomer and the monofunctional (meth) acrylate are contained in the curable resin composition before curing. May occur in the cured product of the curable resin composition without sufficient mixing. In a cured product in which such phase separation occurs, various physical properties such as electrical insulation and mechanical strength may be insufficient.

Further, when the monofunctional (meth) acrylate is contained in the curable resin composition, the odor (mainly the acrylic odor) generated from the cured product of the curable resin composition may become strong.

However, in a curable resin composition containing a monofunctional (meth) acrylate monomer, sufficient studies have still been made on suppressing the occurrence of phase separation in the cured product and suppressing the generation of odor from the cured product. Has not been done.

Therefore, although the present invention contains a monofunctional (meth) acrylate monomer, the curability can relatively suppress the occurrence of phase separation in the cured product and can relatively suppress the generation of odor from the cured product. An object of the present invention is to provide a resin composition.

As a result of diligent studies by the present inventors, the curable resin composition has a curable compound having a branched polyolefin structure and a (meth) acryloyl group in the molecule, a specific tackifier, and a saturated chain. The present invention has been found that by containing (meth) acrylate, the occurrence of phase separation in the cured product can be relatively suppressed and the generation of odor from the cured product can be relatively suppressed. I came up with the idea.

That is, the curable resin composition according to the present invention is
A curable compound having a branched-chain polyolefin structure and a (meth) acryloyl group in the molecule,
Adhesive agent and
Contains saturated chain (meth) acrylates,
The tackifier includes a hydrocarbon resin having a structural unit of α-methylstyrene or a structural unit of a hydrogenated product thereof in the molecule.

According to such a configuration, since the saturated chain (meth) acrylate is contained, the generation of odor from the cured product can be relatively suppressed.
Further, since the tackifier contains a hydrocarbon having a structural unit of α-methylstyrene or a structural unit of a hydrogenated product thereof in the molecule, the curable compound and the saturated chain (meth) acrylate are contained. Affinity with can be relatively improved. Therefore, it is possible to relatively suppress the occurrence of phase separation in the cured product.

In the above curable resin composition,
The saturated chain (meth) acrylate preferably has a hydrocarbon portion having 9 or more and 12 or less carbon atoms.

According to such a configuration, the generation of odor from the cured product can be further suppressed, and the occurrence of phase separation in the cured product can be further suppressed.

In the above curable resin composition,
The saturated chain (meth) acrylate is preferably at least one of isononyl acrylate and isodecyl acrylate.

According to such a configuration, the generation of odor from the cured product can be further suppressed, and the occurrence of phase separation in the cured product can be further suppressed.

In the above curable resin composition,
The curable compound preferably further contains an isocyanate group in the molecule.

According to such a configuration, the curable resin composition can be cured not only by light irradiation but also by humidity.

According to the present invention, although it contains a monofunctional (meth) acrylate monomer, curability that can relatively suppress the occurrence of phase separation in the cured product and relatively suppress the generation of odor from the cured product. A resin composition can be provided.

Hereinafter, embodiments of the present invention will be described.

The curable resin composition according to the present embodiment contains a curable compound having a branched-chain polyolefin structure and a (meth) acryloyl group in the molecule, a tackifier, and a saturated chain-like (meth) acrylate. Including.
In the resin composition according to the present embodiment, the tackifier includes a hydrocarbon resin having a structural unit of α-methylstyrene or a structural unit of a hydrogenated product thereof in the molecule.
In the present specification, the (meth) acryloyl group means at least one of an acryloyl group and a meta-acryloyl group, and the (meth) acrylate means at least one of an acrylate and a methacrylate.

The curable compound is not particularly limited as long as it is a compound having a branched-chain polyolefin structure and at least one (meth) acryloyl group in the molecule.

Examples of the curable compound include those represented by the following general formula (1).

ただし、一般式（１）において、Ｘは、分岐鎖状のポリオレフィン構造を示し、Ｙ’およびＹ”は、それぞれ、下記一般式（Ａ）〜（Ｄ）のいずれかを示している。
各一般式（Ａ）〜（Ｄ）において、Ｚ^１及びＺ^２は、それぞれ独立して、下記一般式（α）で示される分子構造、または、−ＮＣＯを示す。
各一般式（Ａ）〜（Ｄ）のＹ’及びＹ”のそれぞれにおいて、２つのＺ^１及び２つのＺ^２は全てが下記一般式（α）で示される分子構造であってもよいし、２つのＺ^１及び２つのＺ^２のうちの少なくとも１つが下記一般式（α）で示される分子構造であり、それ以外は−ＮＣＯであってもよい。
要すれば、各一般式（Ａ）〜（Ｄ）において、下記一般式（α）で示される分子構造が含まれていればよい。

However, in the general formula (1), X represents a branched-chain polyolefin structure, and Y'and Y "represent one of the following general formulas (A) to (D), respectively.
In each of the general formulas (A) to (D), Z ¹ and Z ² independently represent the molecular structure represented by the following general formula (α) or -NCO.
In each of Y 'and Y "each formula (A) ~ (D), all the two Z ¹ and two Z ² is may be a molecular structure represented by the following general formula (alpha), two at least one of Z ¹ and two Z ² is a molecular structure represented by the following general formula (alpha), the other may be -NCO.
If necessary, each of the general formulas (A) to (D) may include the molecular structure represented by the following general formula (α).

ただし、一般式（Ａ）において、Ｒ^ａ１、Ｒ^ａ２、及び、Ｒ^ａ３は、それぞれ独立して、有機官能基を示し、Ｚ^１及びＺ^２は、上記した通りである。

However, in the general formula (A), Ra ¹ , Ra ² , and Ra ³ independently represent organic functional groups, and Z ¹ and Z ² are as described above.

ただし、一般式（Ｂ）において、Ｒ^ｂ１、Ｒ^ｂ２、Ｒ^ｂ３、及び、Ｒ^ｃは、それぞれ独立して、有機官能基を示し、Ｚ^１及びＺ^２は、上記した通りである。

However, in the general formula (B), R ^b1 , R ^b2 , R ^b3 , and R ^c each independently represent an organic functional group, and Z ¹ and Z ² are as described above.

ただし、一般式（Ｃ）において、Ｒ^ｄ１、Ｒ^ｄ２、及び、Ｒ^ｄ３は、それぞれ独立して、有機官能基を示し、Ｚ^１及びＺ^２は、上記した通りである。

However, in the general formula (C), R ^d1 , R ^d2 , and R ^d3 independently represent organic functional groups, and Z ¹ and Z ² are as described above.

ただし、一般式（Ｄ）において、Ｒ^ｅ１、Ｒ^ｅ２、及び、Ｒ^ｅ３は、それぞれ独立して、有機官能基を示し、Ｚ^１及びＺ^２は、上記した通りである。

However, in the general formula (D), ^{Re 1} , ^{Re 2} , and ^{Re 3} independently represent organic functional groups, and Z ¹ and Z ² are as described above.

ただし、一般式（α）において、Ｑは、炭素数２〜４の飽和炭化水素基を示し、Ｍは、ＨまたはＣＨ_３を示している。

However, in the general formula (α), Q represents a saturated hydrocarbon group having 2 to 4 carbon atoms, and M represents H or CH ₃ .

In the curable resin composition according to the present embodiment, since the curable compound has a (meth) acryloyl group in the molecule, when the curable resin composition is irradiated with light such as ultraviolet rays, the curable compounds are used together. Will undergo a polymerization reaction. Then, by the polymerization reaction between the curable resin compositions, the polymerization (curing reaction) proceeds, and the curable resin composition is cured.
In addition to this, in the curable resin composition according to the present embodiment, the curable compound may further contain an isocyanate group (-NCO) in the molecule, and in this case, moisture in the air (in this case). Moisture) also causes the curable compounds to undergo a polymerization reaction with each other, and this polymerization reaction also promotes polymerization (curing reaction), so that the curable resin composition is cured.
That is, when the curable compound contains both a (meth) acryloyl group and an isocyanate group in the molecule, in the curable resin composition, polymerization (curing reaction) is added to light irradiation. Since it can also proceed with moisture, the curing reaction can proceed more sufficiently.

As described above, in the above general formula (1), X is a branched-chain polyolefin structure. In the polyolefin structure, the polyolefin is preferably a saturated polyolefin. That is, the polyolefin in X is preferably a branched-chain saturated polyolefin. Examples of the branched-chain saturated polyolefin include hydrogenated (hydrogenated) polybutadiene.

The molecular weight of the polyolefin in the general formula (1) is preferably 1000 or more and 6000 or less. When the molecular weight of the polyolefin is 1000 or more, it is possible to further suppress the deterioration of the mechanical properties of the cured product after the curable resin composition has become a cured product. Further, when the molecular weight of the polyolefin is 6000 or less, it is further suppressed that after the curable resin composition becomes a cured product, phase peeling occurs in the cured product and the cured product becomes non-uniform. be able to.
The molecular weight of the polyolefin can be determined by a standard polystyrene-equivalent value measured by GPC (gel permeation chromatography) before synthesizing the curable compound of the general formula (1).

In the general formula (1), Y'and Y "contains an isocyanurate structure, an adduct body structure, or a biuret body structure of an aliphatic diisocyanate having a total carbon number of 6 to 10, respectively.
Explaining in more detail using the general formulas (A) to (D) described _{above, the portion obtained by removing Z 1} and Z ₂ from the structure represented by the general formula (A) is the above-mentioned isocyanurate body structure, which is the general formula. structure from excluding Z ₁ and Z ₂ moiety represented by (B) is an adduct structure described above, the general formula (C) or (D) structure from excluding Z ₁ and Z ₂ moiety represented by This is the biuret body structure described above.

Prior to forming the isocyanurate structure, adduct structure, or biuret structure, the aliphatic diisocyanate having a total carbon number of 6 to 10 has both linear alkylene groups having a carbon number of 4 to 8. It has an isocyanate group at the end.
Here, since Y'and Y'are composed of, for example, an aliphatic diisocyanate isocyanurate structure, an adduct structure, or a biuret structure, they have a benzene ring structure and a saturated cycloalkyl structure (the ring is a carbon atom). Does not include any of the saturated structures composed only of.
As described above, when Y'and Y'do not have a benzene ring structure and a saturated cycloalkyl structure, after the curable resin composition according to the present embodiment becomes a cured product, the cured product is heat-resistant. It has better properties and weather resistance.

Examples of the aliphatic diisocyanate having 6 to 10 total carbon atoms include hexamethylene diisocyanate (HMDI).

The isocyanurate form is a trimer of the aliphatic diisocyanate. The structure of the trimer excluding the terminal isocyanate group (-NCO) corresponds to the structure of the general formula (A) excluding ^{Z 1} and Z ^2.

The adduct is a reaction product of the aliphatic diisocyanate and triol having 3 to 6 carbon atoms. The structure excluding the terminal isocyanate group in the reaction product corresponds to the structure excluding ^{Z 1} and Z ^{2 from the above general formula (B).}
A triol having 3 to 6 carbon atoms is composed of only a carbon atom (C), an oxygen atom (O), and a hydrogen atom (H). Examples of the triol having 3 to 6 carbon atoms include trimethylolpropane (CH _3- CH _2- C (CH _2- OH) ₃ ), glycerin and the like.

The biuret form is a reaction product of the aliphatic diisocyanate with water or a tertiary alcohol. The structure of the portion inside the terminal diisocyanate in the reaction product corresponds to the structure obtained by removing ^{Z 1} and Z ² from the general formula (C) or the general formula (D).

In the general formula (1), Y'and Y "may have the same molecular structure or different molecular structures from each other.
Further, in the general formulas (A) to (D), R ^{a1 to} R ^a3 , R ^b1 to ^b3 , R ^c , R ^{d1 to} R ^d3 , and R ^{e1 to} R ^e3 are organic functional groups containing at least a carbon atom. Is. R ^{a1 to} R ^a3 , R ^b1 to ^b3 , R ^c , R ^{d1 to} R ^d3 , and R ^{e1 to} R ^e3 may contain a urea bond, a biuret bond, or an allophanate bond. R ^{a1 to} R ^a3 , R ^b1 to ^b3 , R ^{d1 to} R ^d3 , and R ^{e1 to} R ^e3 are preferably saturated hydrocarbons having 4 to 8 carbon atoms, and linear saturated hydrocarbons having 6 carbon atoms. Although it is more preferably hydrogen, it may contain heteroatoms (N, O, S, P, etc.) or may have a branched chain structure. R ^c is preferably a saturated hydrocarbon of 4 to 8 carbon atoms, is preferably a branched chain saturated hydrocarbon having 6 carbon atoms, hetero atoms (N, O, S, P, etc.) include It may be used, or it may have a linear structure.

In the general formula (1), Z ¹ and Z ² may be the same as each other or may be different from each other. Further, in the general formula (1), because each Y 'and Y "contains ^{Z 1} and ^{Z 2,} wherein the in the general formula (1), two ^{Z 1} is present and the two Z ² it may be .2 one of Z ^1, which will be present the same as each other, may be the same as each other also Z ² of one .2 which may be different from each other, may be different from each other. That is, two of Z ¹ and two Z ² are each defined separately and independently.

In the general formula (α), Q showing a saturated hydrocarbon group having 2 to 4 carbon atoms is preferably linear. That is, Q is preferably a linear saturated hydrocarbon group having 2 to 4 carbon atoms. The saturated hydrocarbon group in Q preferably has 2 carbon atoms.

Examples of the curable compound represented by the general formula (1) include compounds represented by the following formulas (1a) to (1f). The compounds represented by the following formulas (1a) to (1f) all contain an isocyanate group (-NCO).
In the compounds represented by the following formulas (1a) to (1f), the isocyanate group may be replaced with the molecular structure represented by the above formula (α). That is, it may be a compound containing no isocyanate group.

ただし、Ｒ^ａ１、Ｒ^ａ２、及び、Ｒ^ａ３は、それぞれ独立して、有機官能基を有し、炭素数が４〜８である直鎖状飽和炭化水素であることが好ましく、ｐは、２０〜３００であり、Ｍは、ＨまたはＣＨ_３である。

However, Ra ¹ , Ra ² , and Ra ³ are preferably linear saturated hydrocarbons each independently having an organic functional group and having 4 to 8 carbon atoms, and p is 20. ~ 300, where M is H or CH ₃ .

ただし、Ｒ^ａ１、Ｒ^ａ２、及び、Ｒ^ａ３は、それぞれ独立して、有機官能基を有し、炭素数が４〜８である直鎖状飽和炭化水素であることが好ましく、ｐは、２０〜３００であり、Ｍは、ＨまたはＣＨ_３である。

However, Ra ¹ , Ra ² , and Ra ³ are preferably linear saturated hydrocarbons each independently having an organic functional group and having 4 to 8 carbon atoms, and p is 20. ~ 300, where M is H or CH ₃ .

ただし、Ｒ^ａ１、Ｒ^ａ２、及び、Ｒ^ａ３は、それぞれ独立して、有機官能基を有し、炭素数が４〜８である直鎖状飽和炭化水素であることが好ましく、ｐは、２０〜３００であり、Ｍは、ＨまたはＣＨ_３である。

However, Ra ¹ , Ra ² , and Ra ³ are preferably linear saturated hydrocarbons each independently having an organic functional group and having 4 to 8 carbon atoms, and p is 20. ~ 300, where M is H or CH ₃ .

ただし、Ｒ^ｂ１、Ｒ^ｂ２、及び、Ｒ^ｂ３は、それぞれ独立して、有機官能基を有し、炭素数が４〜８である直鎖状飽和炭化水素であることが好ましく、ｐは、２０〜３００であり、Ｍは、ＨまたはＣＨ_３である。

However, R ^b1 , R ^b2 , and R ^b3 are preferably linear saturated hydrocarbons each independently having an organic functional group and having 4 to 8 carbon atoms, and p is 20. ~ 300, where M is H or CH ₃ .

ただし、Ｒ^ｂ１、Ｒ^ｂ２、及び、Ｒ^ｂ３は、それぞれ独立して、有機官能基を有し、炭素数が４〜８である直鎖状飽和炭化水素であることが好ましく、ｐは、２０〜３００であり、Ｍは、ＨまたはＣＨ_３である。

However, R ^b1 , R ^b2 , and R ^b3 are preferably linear saturated hydrocarbons each independently having an organic functional group and having 4 to 8 carbon atoms, and p is 20. ~ 300, where M is H or CH ₃ .

ただし、Ｒ^ｂ１、Ｒ^ｂ２、及び、Ｒ^ｂ３は、それぞれ独立して、有機官能基を有し、炭素数が４〜８である直鎖状飽和炭化水素であることが好ましく、ｐは、２０〜３００であり、Ｍは、ＨまたはＣＨ_３である。

However, R ^b1 , R ^b2 , and R ^b3 are preferably linear saturated hydrocarbons each independently having an organic functional group and having 4 to 8 carbon atoms, and p is 20. ~ 300, where M is H or CH ₃ .

As the molecular structure represented by the general formula (α), the one represented by the following formula (α-1) is preferable. By having the molecular structure represented by the following formula (α-1), it has an ethylene group having relatively few steric hindrances, so that the polymerization rate by irradiation with light such as ultraviolet rays can be increased.
When the carbon number of Q in the general formula (α) is 1 (that is, when it is a methylene group), the curable resin composition is easily decomposed when it is cured.

The curable resin composition according to the present embodiment includes, for example, a branched polyolefin diol (hereinafter, also simply referred to as component A), an isocyanurate of an aliphatic diisocyanate having a total carbon number of 6 to 10, and an adduct. body, and, at least one selected from biuret (hereinafter, simply referred to as component B) a hydroxy saturated C ₁ -C ₄ alkyl (meth) acrylate (hereinafter, also simply referred to as component C) and, of Contains urethanization reaction products.
That is, the curable resin composition according to the present embodiment is, for example, a curable compound obtained by subjecting at least the A component, the B component, and the C component to a urethanization reaction, the tackifier, and the saturated chain (saturated chain). Includes with meta) acrylate.

The curable compound is at least a part of the urethanization reaction product of the A component, the B component, and the C component. That is, the curable compound can be obtained by at least reacting the A component, the B component, and the C component with a urethanization reaction.

For example, the curable resin composition according to the present embodiment contains at least the curable compound represented by the general formula (1) as the above-mentioned urethanization reaction product.
In addition to the curable compound represented by the general formula (1), the curable resin composition according to the present embodiment also contains a by-product produced by the urethanization reaction.
Further, the curable resin composition according to the present embodiment also contains a trace amount of urethanization reaction catalyst compounded for the urethanization reaction. The urethanization reaction product will be described later.

Since the curable resin composition according to the present embodiment contains at least the curable compound represented by the general formula (1), it can be cured by irradiation with light such as ultraviolet rays as described above. Further, as represented by the general formulas (1a) to (1f), when an isocyanate group (-NCO) is contained, it can be cured by humidity.
Further, the curable resin composition according to the present embodiment also contains a by-product produced by the urethanization reaction, and when the by-product also contains an isocyanate group, it is added to irradiation with light such as ultraviolet rays. Therefore, a curing reaction can occur due to moisture. That is, when the by-product also contains an isocyanate group, it can be cured not only by irradiation with light such as ultraviolet rays but also by humidity.

<Component A>
The component A is a branched-chain polyolefin diol. Each polyolefin diol has a hydroxy group at the end of the molecule. In the polyolefin diol, the olefin moiety does not contain polar groups such as ether groups and ester groups, and is composed only of saturated hydrocarbons.

Examples of the component A include polypropylene diols, polybutene diols (hydrogenated 1,2-polybutadiene diols), hydrogenated polyisoprene diols, and the like. As the component A, polybutene diol (hydrogenated 1,2-polybutadiene diol) is preferable from the viewpoint of imparting sufficient mechanical flexibility to the cured product (coating film) after curing.

The molecular weight of component A is preferably 1000 or more and 6000 or less.

<B component>
The B component is a polyisocyanate, which is at least one selected from an isocyanate body, an adduct body, and a biuret body of an aliphatic diisocyanate having a total carbon number of 6 to 10. The B component has 3 or 4 isocyanate groups in the molecule.

The isocyanurate form as the B component is, for example, a trimer of hexamethylene diisocyanate (HMDI) and has three isocyanate groups in the molecule.

The adduct as the B component is, for example, a reaction product of trimethylolpropane and an aliphatic isocyanate having a total carbon number of 6 to 10 (such as the above-mentioned HMDI). The adduct has three isocyanate groups in the molecule.

Since the B component does not contain a benzene ring, the weather resistance after curing can be improved, and when a diluent is used in the urethanization reaction, the solubility in the diluent is sufficient. Isocyanurate (trimer) of hexamethylene diisocyanate (HMDI) or an adduct obtained by reacting hexamethylene diisocyanate (HMDI) with trimethylolpropane. Is preferable.

<C component>
C component is a (meth) _C 1 -C ₄ saturated alkyl esters of acrylic acid. The saturated alkyl ester has one hydroxy group bonded to any carbon of the alkyl moiety. C component is preferably a hydroxy saturated _C 2 -C ₃ alkyl (meth) acrylate.

Examples of the C component include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 4-hydroxybutyl (meth). Examples include acrylate. The C component is preferably 2-hydroxyethyl (meth) acrylate, more preferably 2-hydroxyethyl acrylate, from the viewpoint of improving the polymerizable property by irradiation with light such as ultraviolet rays.

The molar ratio of component B to component A in the urethanization reaction is preferably 2.0 or more and 2.5 or less, and more preferably 2.0 or more and 2.2 or less.

The molar ratio of the C component to the B component in the urethanization reaction is preferably 0.5 or more and 2.0 or less, and more preferably 0.5 or more and 1.5 or less.

The molar ratio of the C component to the A component in the urethanization reaction is preferably 1.0 or more and 4.0 or less, and more preferably 1.0 or more and 3.0 or less.

<Urethane reaction catalyst>
As the urethanization reaction catalyst, an organic tin catalyst such as dibutyltin dilaurylate or stanas octoate, a metal-based catalyst such as an acetylacetonate complex catalyst, etc. can be used.
A tertiary amine catalyst can also be used as the urethanization reaction catalyst.

The curable resin composition (resin composition for curing) according to the present embodiment contains a urethanization reaction product produced by a urethanization reaction in the presence of a component A, a component B, and a component C.

Examples of the urethanization reaction product include compounds represented by the general formula (1) such as the general formulas (1a) to (1f).

Further, examples of the urethanization reaction product include a compound having only an isocyanate group as a reactive group, a compound having only a hydroxy group as a reactive group, and the like.
The urethanization reaction product is, for example, a urethanization reaction product of the A component and the B component, which is a compound in which the C component is not introduced into the molecule, and the urethanization of the B component and the C component. Examples of the reaction product include compounds in which the A component is not introduced into the molecule.

The curable resin composition according to the present embodiment contains a saturated chain (meth) acrylate as described above.
Saturated chain (meth) acrylate is a photopolymerizable monomer that does not undergo a urethanization reaction. As the saturated chain (meth) acrylate, it is preferable to use a hydrocarbon portion having 9 or more and 12 or less carbon atoms. When the number of carbon atoms in the hydrocarbon portion is in such a numerical range, the volatility can be made relatively low, so that the generation of odor can be relatively suppressed and phase separation occurs. Can be relatively suppressed.
As such a saturated chain (meth) acrylate, it is preferable to use lauryl acrylate, isononyl acrylate, and isodecyl acrylate. Among these, it is particularly preferable to use isononyl acrylate and isodecyl acrylate. The isononyl acrylate and the isodecyl acrylate may be used alone or in combination.
Such a saturated chain (meth) acrylate as a photopolymerizable monomer may be blended as a diluent before the urethanization reaction in order to reduce the viscosity in the urethanization reaction system, or may be blended after the urethanization reaction. Good. Saturated chain (meth) acrylate is a compound that produces a polymerization reaction product when irradiated with light such as ultraviolet light.
Since the curable resin composition according to the present embodiment contains a saturated chain (meth) acrylate as a photopolymerizable monomer, the curable resin composition contains an alicyclic (meth) acrylate as a photopolymerizable monomer. As compared with the above, it is possible to suppress the generation of odor (mainly acrylic odor) from the cured product of the curable resin composition.

The curable resin composition according to the present embodiment may contain unreacted A component, B component, and C component that have not undergone urethanization reaction.
In addition, the curable resin composition according to the present embodiment may contain a urethanization reaction catalyst formulated to promote the urethanization reaction.
As described above, the curable resin composition according to the present embodiment contains various reaction products and unreacted components. Therefore, it can be said that it is not practical to specify the molecular structure of all the contained compounds. That is, it can be said that it is almost impractical to directly specify the structure or property of all the compounds contained in the curable resin composition according to the present embodiment. However, since the molecular structure of the compound before the urethanization reaction has been specified and the product can be sufficiently predicted by the urethanization reaction, the molecular structure of the reaction product (main reaction product and side reaction product) should be predicted. Is quite possible.

The curable resin composition according to the present embodiment may contain an isocyanate monomer, a photopolymerization initiator and the like further added after the urethanization reaction.

The photopolymerization initiator is not particularly limited as long as it is a compound that generates radicals when irradiated with light such as ultraviolet rays. Examples of the photopolymerization initiator include an acetophenone-based photoinitiator, a benzoin-based photoinitiator, a benzophenone-based photoinitiator, a thioxanthone-based photoinitiator, and an acylphosphine oxide-based photoinitiator.
As the photopolymerization initiator, a commercially available product can be used.

The curable resin composition according to the present embodiment may contain a photosensitizer, a polymerization inhibitor, an antioxidant, a dye, a pigment, a phosphor and the like, if necessary.

As described above, the curable resin composition according to the present embodiment contains a hydrocarbon resin having a structural unit of α-methylstyrene or a structural unit of a hydrogenated product thereof in the molecule.

Here, as described above, when the curable resin composition contains a saturated chain (meth) acrylate, it is possible to relatively suppress the generation of odor from the cured product of the curable resin composition. However, since the saturated chain (meth) acrylate has a lower affinity for the curable compound than the alicyclic (meth) acrylate, phase separation occurs in the curable resin composition before curing. Due to this, phase separation also occurs in the cured product of the curable resin composition.
However, as described above, the curable resin composition according to the present embodiment contains a hydrocarbon resin having a structural unit of α-methylstyrene or a structural unit of a hydrogenated product thereof in the molecule. The affinity between the curable compound and the saturated chain (meth) acrylate can be relatively enhanced.
Therefore, since it is possible to relatively suppress the occurrence of phase separation in the curable resin composition before curing, it is possible to relatively suppress the occurrence of phase separation also in the cured product of the curable resin composition.
That is, the curable resin composition according to the present embodiment contains a saturated chain (meth) acrylate and a hydrocarbon resin having a structural unit of α-methylstyrene or a structural unit of a hydrogenated product thereof in the molecule. Therefore, it is possible to relatively suppress the occurrence of phase separation in the cured product, and it is possible to relatively suppress the generation of odor from the cured product.

The tackifier may contain 90% by mass or more of a hydrocarbon resin having a structural unit of α-methylstyrene or a structural unit of a hydrogenated product thereof in the molecule with respect to the total mass of the tackifier. preferable. It is more preferable that all of the tackifiers are the above-mentioned hydrocarbon resins.

In addition to the structural unit of α-methylstyrene, the above hydrocarbon resin may be, for example, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, t-butylstyrene, 2,4-dimethylstyrene, or It has a structural unit of 2,4,6-trimethylstyrene in the molecule.
The above hydrocarbon resin may have an indene structural unit in the molecule.

The above hydrocarbon resin is preferably a copolymer of at least α-methylstyrene and at least one of styrene or methylstyrene. The above hydrocarbon resin is more preferably copolymerized with α-methylstyrene, at least one of styrene or methylstyrene, and indene.

The above hydrocarbon resin preferably has a molecular structure as represented by the following formula (14) or (15). The following formula (14) shows a structure in which hydrogen is not added to the benzene ring, and the following formula (15) shows a structure in which hydrogen is added to the benzene ring (hydrogenation structure). The hydrogenated structure may be either a partially hydrogenated structure or a completely hydrogenated structure, but a completely hydrogenated structure is preferable.
_{In addition, R 1} in the following formulas (14) and (15) is a methyl group. In the following equations (14) and (15), R ₁ may not be present. In the following formulas (14) and (15), R ₁ may be bonded to any one or more positions of the benzene ring.

The softening point of the above hydrocarbon resin is preferably 70 ° C. or higher and 150 ° C. or lower. When the softening point of the hydrocarbon resin is 70 ° C. or higher and 150 ° C. or lower, the cured product is made to have better insulation reliability after the curable resin composition becomes a cured product. Can be done.

The softening point of the above hydrocarbon resin is measured by the following method. Specifically, it is measured according to the JIS K2207-1996 softening point test method (ring ball method).
The above measurement can be carried out using, for example, an automatic softening point tester "asp-6" (manufactured by Tanaka Scientific Instruments Manufacturing Co., Ltd.). The measurement conditions are as follows.
・ Two ring-ball type ・ Glycerin bath + stirring mode ・ Magnetic stirrer 80-300 rpm

As the above hydrocarbon resin, a commercially available product can be used. Examples of commercially available products include the Archon series (manufactured by Arakawa Chemical Industry Co., Ltd.). In the Archon series, it is preferable to use Archon 100 (Arcon M-100 and Archon P-100).

Next, one embodiment of the method for producing a curable resin composition according to this embodiment will be described. In the following, a method for producing a curable resin composition containing an isocyanate group will be described as an example.

In the method for producing a curable resin composition according to the present embodiment, for example, an isocyanurate form or an adduct form of a branched polyolefin diol (the component A) and an aliphatic diisocyanate having a total carbon number of 6 to 10 is used. The reaction of the urethanization reaction by the urethanization reaction in the presence of at least one selected from the biuret form (the B component) and the hydroxysaturated C1 to C4 alkyl (meth) acrylate (the C component). A curable resin composition containing a product is produced.

More specifically, the method for producing a curable resin composition according to the present embodiment is the above-mentioned curing by the urethanization reaction in the presence of the A component, the B component, the C component, and the urethanization reaction catalyst. A reaction step for obtaining a urethanization reaction product containing a sex compound is provided.
Further, in the method for producing a curable resin composition according to the present embodiment, after the reaction step, a saturated chain (meth) acrylate as a photopolymerizable monomer, an isocyanate monomer, and the tackifier (α-methylstyrene structure) are used. It is provided with an addition step of further adding a unit or a tackifier containing a hydrocarbon resin having a structural unit of the hydrogenated product in the molecule) and a photopolymerization initiator.

The components A, B, C, and the urethanization reaction catalyst used in the reaction step are as described above.

In the method for producing a curable resin composition according to the present embodiment, in order to prevent a reaction with moisture contained in humidity, the reaction step is usually carried out after replacing the air in the reaction vessel with nitrogen.

In the reaction step, general reaction conditions suitable for the urethanization reaction can be adopted. In the reaction step, it is preferable to carry out the urethanization reaction by holding for 0.5 to 3 hours in a temperature atmosphere of 50 to 70 ° C.

In the reaction step, the ratio (molar ratio) of the preferable blending amounts of the A component, the B component, and the C component is as described above.

In the reaction step, a compound that is not involved in the urethanization reaction and that produces a polymerization reaction product by light irradiation, that is, a saturated chain (meth) acrylate as a photopolymerizable monomer may coexist. ..
Further, in the reaction step, the tackifier, which is a compound not involved in the urethanization reaction, may coexist.
Further, in the reaction step, an isocyanate monomer, which is a compound not involved in the urethanization reaction, may coexist.

Here, since the saturated chain (meth) acrylate and isocyanate monomer added as the photopolymerizable monomer in the addition step have low viscosity, they serve as a solvent for diluting the curable resin composition. On the other hand, since it is cured by irradiation with light such as ultraviolet rays or moisture, it also plays a role of more sufficiently curing the curable resin composition.
Further, when the saturated branched chain (meth) acrylate and the isocyanate monomer are blended, the viscosity of the curable resin composition before curing can be made relatively low, so that the curable resin composition before curing is applied. The process to be performed can be performed more smoothly.

In the addition step, a photosensitizer, a polymerization inhibitor, an antioxidant, a dye, a pigment, a phosphor, or the like may be further added, if necessary.

The curable resin composition according to the present embodiment is used as a cured product cured by irradiation with light such as ultraviolet rays. For example, after the electronic circuit to be coated is coated with the curable resin composition, the curable resin composition after coating is irradiated with light such as ultraviolet rays to irradiate the curable resin composition with light such as ultraviolet rays. Is cured to form a coating film of the cured product.
When the curable resin composition contains an isocyanate group (-NCO), the curing reaction due to the humidity (moisture) in the air is further promoted by leaving it in the air for several hours to several days. ..

Ultraviolet rays can be used as the light to be irradiated to proceed the curing reaction. As the plateau, high-pressure mercury lamps, metal halide lamps, xenon lamps, chemical lamps, LED lamps and the like can be used. As the irradiation intensity, 10 to 10,000 mW / cm ² can be adopted.

When the curable resin composition contains an isocyanate group (-NCO), the temperature of the air left to allow the curing reaction due to humidity to proceed is preferably 20 to 40 ° C., and the humidity of the air. Is preferably 40 to 90% RH.

The target to which the curable resin composition is coated and coated is, for example, an electronic circuit or terminal on a mounting substrate used for precision equipment, an automobile, a bicycle, a railroad, an aircraft, a ship, or the like. Electronic circuits and terminals on the mounting board, electronic circuits and terminals on the mounting board used for mobile devices (mobile phones, digital cameras, digital video cameras, etc.), water around washing machines, hot water washing toilet seats, dishwashers, etc. Examples include electronic circuits and terminals on a mounting board used in equipment.

The curable resin composition according to the present invention is not limited to the above embodiment. Further, the curable resin composition according to the present invention is not limited by the above-mentioned effects. The curable resin composition according to the present invention can be variously modified without departing from the gist of the present invention.

Next, the present invention will be described in more detail with reference to Examples and Comparative Examples. The present invention is not limited to the following examples as long as the gist of the present invention is not exceeded.

(Example 1)
As described below, (A) to (C) (components A to C) are mixed and subjected to a urethanization reaction to obtain a curable resin composition containing the curable compound represented by the above general formula (1). It was.

[Raw materials for reaction process]
(A) Hydrogenated polybutadiene diol (average molecular weight 3,1000)
Product name "NISSO-PB GI-3000"
: Hydrogen base value (KOHmg / g = 30mg) Manufactured by Nippon Soda Co., Ltd. (B) Aliphatic diisocyanate derivative with total carbon number of 6 to 10 ・ Hexamethylene diisocyanate (HMDI) isocyanurate derivative Product name "DURANATE TPA-100" : Isocyanate group content 23.1% "Asahi Kasei Co., Ltd. (C) hydroxysaturated C1-C4 alkyl (meth) acrylate / 2-hydroxyethyl acrylate (commercially available)
(Other)
-Photopolymerizable monomer 1 (reaction solvent / diluent)
Either isononyl acrylate (commercially available) or isobornyl acrylate (commercially available) -Urethane reaction catalyst Dibutyltin dilaurate (commercially available)
・ Adhesive imparting agent (hydrocarbon resin)
Product name "Arcon 100" manufactured by Arakawa Chemical Industry Co., Ltd.

[Raw materials for addition process]
-Photopolymerizable monomer 1
Either isononyl acrylate (commercially available) or isobornyl acrylate (commercially available) -Photopolymerizable monomer 2 (polyfunctional isocyanate)
Hexamethylene diisocyanate (HMDI) isocyanurate derivative Product name "DURANATE TPA-100: Isocyanate group content 23.1%" Asahi Kasei Co., Ltd., tackifier (hydrocarbon resin)
Product name "Arcon 100" Photopolymerization initiator manufactured by Arakawa Chemical Industry Co., Ltd. Product name "IRGACURE 907" Photosensitizer manufactured by IGM Resins (2,4-diethylthioxanthone)
Product name "KAYACURE DETX-S" manufactured by Nippon Kayaku Co., Ltd.

In the blending amounts shown in Table 1 below, the above (A), (B), (C), isononyl acrylate as a photopolymerizable monomer (reaction solvent / diluent), urethanization reaction catalyst, and tackifier. The reaction step was carried out by carrying out the urethanization reaction for 1 hour in a temperature atmosphere of 60 ° C. in the presence of.
Next, the above raw materials were added and mixed with the composition after the reaction step at the blending amounts shown in Table 1 below, and the addition step was carried out.
In this way, a curable resin composition was obtained.

(Comparative Example 1)
A curable resin composition was obtained with the compounding composition shown in Table 1 below in the same manner as in Example 1 except that a tackifier was not used as a raw material for the reaction step and a raw material for the addition step.

(Comparative Example 2)
In the same manner as in Example 1, except that an tackifier was not used as a raw material for the reaction step and a tackifier was used as the raw material for the addition step, and isobornyl acrylate was used as the photopolymerizable monomer instead of isononyl acrylate. A curable resin composition was obtained with the compounding composition shown in Table 1 below.

The viscosity of the curable resin composition according to each example before curing was measured, and the presence or absence of phase separation was visually observed.
The viscosity was measured at 25 ° C. using an E-type (cone-plate type) rotational viscometer.
Further, the presence or absence of phase separation of the curable resin composition according to each example before curing was determined by confirming the presence or absence of turbidity of the curable resin composition according to each example before curing. Specifically, after confirming that the resin composition had been cooled to room temperature (23 ± 2 ° C.) after the addition step was completed, turbidity was observed as a result of visually observing the curable resin composition according to each example before curing. Those that did not have phase separation were evaluated as ◯, and those that did not show turbidity were evaluated as × because phase separation had occurred.
Table 2 below shows the results of measuring the viscosity of the curable resin composition according to each example before curing and the results of evaluating the presence or absence of phase separation.

In addition, the odor generated from the curable resin composition (cured product) according to each example after curing is evaluated by a sensory test, and the phase separation of the curable resin composition (cured product) according to each example after curing is performed. The presence or absence was evaluated.

The curable resin composition according to each example was cured as follows.
(1) The curable resin composition according to each example is coated on a tin plate having a plane dimension of 130 mm × 180 mm and a thickness of 0.3 mm so that the thickness of the cured product after curing is 100 μm.
(2) The curable resin composition according to each example coated on the tin plate is irradiated with ultraviolet rays by a 500 W UV lamp so that the integrated light intensity is 3000 mJ / cm ^2.
(3) The curable resin composition according to each example after irradiation with ultraviolet rays is allowed to stand in a constant temperature and humidity chamber set at 40 ° C./90% RH for 72 hours to be cured by moisture (moisture).

As for the odor generated from the curable resin composition according to each example after curing, 50 g of the curable resin composition according to each example after curing is put in a 100 mL sample bottle, and 10 panelists feel how much acrylic odor. It was evaluated by. The case where the panelist felt almost no odor (only the slight acrylic odor was felt) was marked with ◯, and the case where the panelist felt a strong acrylic odor was marked with x.
In addition, the presence or absence of phase separation of the curable resin composition according to each example after curing was visually evaluated. Those in which the tin plate was visually transparent and completely transparent were marked with ◯, and those in which whitening or turbidity was observed were marked with x.
Table 2 below shows the results of evaluating the odor and the presence or absence of phase separation of the curable resin composition according to each example after curing.

The polymer ratio in Table 2 above means the mass percentages of the A component, the B component, and the C component used in the reaction step with respect to the total mass parts of all the components used in the reaction step and the addition step.

From Table 2, the viscosities measured for the curable resin compositions according to each example before curing were relatively low values of 1000 mPa · s.
On the other hand, in the curable resin compositions according to Example 1 and Comparative Example 2, the presence or absence of phase separation was evaluated as ◯ before and after curing, whereas the curing according to Comparative Example 1 was performed. It was found that the evaluation of the presence or absence of phase separation of the sex resin composition was x before and after curing.
From this, in order to suppress the occurrence of phase separation in the curable resin composition after curing, it is necessary to suppress the occurrence of phase separation in the curable resin composition before curing, that is, visually. It was found that it is necessary to suppress the turbidity confirmed in.
Further, the curable resin composition according to Example 1 and Comparative Example 2 after curing had an odor evaluation of ◯, whereas the curable resin composition according to Comparative Example 2 after curing had an odor. It turned out that the evaluation was ×.
From these results, in order to relatively suppress the occurrence of phase separation in the curable resin composition after curing and to relatively suppress the generation of odor from the curable resin composition after curing, light is used. A hydrocarbon resin (a hydrocarbon resin in which a saturated branched chain (meth) acrylate (isononyl acrylate) is used as a polymerizable monomer, and a structural unit of α-methylstyrene or a structural unit of a hydrogenated product thereof is contained in the molecule as a tackifier. It turned out that it was necessary to use Archon 100).

Claims (4)

A curable compound having a branched-chain polyolefin structure and a (meth) acryloyl group in the molecule,
Adhesive agent and
Contains saturated chain (meth) acrylates,
The tackifier comprises a hydrocarbon resin having a structural unit of α-methylstyrene or a structural unit of a hydrogenated product thereof in the molecule.
Curable resin composition. The saturated chain (meth) acrylate has 9 or more and 12 or less carbon atoms in the hydrocarbon portion.
The curable resin composition according to claim 1. The saturated chain (meth) acrylate is at least one of isononyl acrylate and isodecyl acrylate.
The curable resin composition according to claim 1 or 2. The curable compound further contains an isocyanate group in the molecule.
The curable resin composition according to any one of claims 1 to 3.