JP2017171831A - Curable composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a curable composition that has excellent impact resistance when a nonpolar resin such as a polyolefin is an adherend.SOLUTION: A curable composition comprises an urethane compound having two or more vinyl ether groups in the molecule, a thiol compound having two or more thiol groups in the molecule, a polyester resin, and a radical generator.SELECTED DRAWING: None

Description

  The present invention relates to a curable composition.

Polyolefins such as polypropylene and polyethylene are widely used in automobile interior and exterior parts, electrical equipment exterior parts, daily necessities, and the like because of their excellent moldability and solvent resistance.
However, since polyolefin is a nonpolar resin, there is a problem that it has a low affinity with an adhesive, which is a polar substance, and is difficult to adhere.
Therefore, various adhesives with improved adhesion to polyolefin have been proposed.

For example, a vinyl ether resin composition containing a vinyl ether monomer having two or more vinyl ether groups, a compound having a urethane skeleton and having a vinyl ether group at a terminal, and a photocationic polymerization initiator has been proposed (for example, Patent Document 1).
In addition, it contains a vinyl ether urethane compound having a specific structure, a thiol compound, and a monofunctional (meth) acrylic monomer having a cyclic structure as an adhesive that improves the adhesion to polyolefin by improving the elongation characteristics. The composition which performs is proposed (for example, refer patent document 2).
Furthermore, a resin composition containing a vinyl ether compound, a polyester-based elastomer, and a photocationic polymerization initiator has been proposed (see, for example, Patent Document 3).

JP 2013-053297 A Japanese Patent Laying-Open No. 2015-165018 JP 7-228842 A

  By the way, when the adherend is a polyolefin, the adherend and the adhesive are easily separated by impact. Therefore, in addition to the conventional adhesive strength (so-called peel strength measured by a 180 ° peel test), a shear adhesive strength is also required for an adhesive used for bonding polyolefin.

With regard to the above-mentioned points, the conventional adhesives including the adhesives described in Patent Documents 1 to 3 do not particularly consider the problem of peeling due to impact that may occur when polyolefin is used as an adherend. It was.
For example, in the adhesive described in Patent Document 2, the adhesive strength is improved by increasing the flexibility and improving the elongation characteristics. The kimono is easy to peel off and is vulnerable to impact.

  This invention is made | formed in view of the above situations, and makes it a subject to provide the curable composition excellent in impact resistance when nonpolar resins, such as polyolefin, are used as a to-be-adhered body.

Specific means for solving the problems include the following aspects.
<1> A curable composition comprising a urethane compound having two or more vinyl ether groups in the molecule, a thiol compound having two or more thiol groups in the molecule, a polyester resin, and a radical generator.

  <2> The curable composition according to <1>, wherein the urethane compound is a compound represented by the following formula (1).

[Wherein, -X ¹ - and -X ² - are each _{independently, -C 4 H 8 -, -} C 2 H 4 -, - C 2 H 4 OC 2 H 4 -, - C 2 H 4 OC ₂ H ₄ OC ₂ H ₄ —, —C ₃ H ₆ —, —C ₃ H ₆ OC ₃ H ₆ —, —C ₃ H ₆ OC ₃ H ₆ OC ₃ H ₆ —, or the following formula (2) Represents any of the represented linking groups. -Z- represents a linking group represented by the following formula (3). L represents at least one skeleton selected from an ester skeleton, a caprolactone skeleton, an ether skeleton, and a carbonate skeleton. ]

  <3> The curable composition according to <1> or <2>, wherein the content of the polyester resin in the curable composition is 15 parts by mass or more and 240 parts by mass or less with respect to 100 parts by mass of the urethane compound.

  <4> The curable composition according to any one of <1> to <3>, in which the polyester resin is a chlorinated polyester resin.

  <5> The curable composition according to any one of <1> to <4>, wherein the polyester resin has a weight average molecular weight of 400 or more and 100,000 or less.

  <6> The curable composition according to any one of <1> to <5>, which is used for adhesion to an olefin resin.

  According to the present invention, it is possible to provide a curable composition having excellent impact resistance when a nonpolar resin such as polyolefin is used as an adherend.

  Hereinafter, specific embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments, and may be implemented with appropriate modifications within the scope of the object of the present invention. be able to.

In the present specification, a numerical range indicated using “to” means a range including the numerical values described before and after “to” as a minimum value and a maximum value, respectively.
In this specification, the amount of each component in the composition is the total amount of the plurality of substances present in the composition unless there is a specific indication when there are a plurality of substances corresponding to each component in the composition. Means.

[Curable composition]
The curable composition of the present invention comprises a urethane compound having two or more vinyl ether groups in the molecule (hereinafter referred to as “vinyl ether group-containing urethane compound” as appropriate) and a thiol compound having two or more thiol groups in the molecule. (Hereinafter referred to as “polyfunctional thiol compound” as appropriate), a polyester resin, and a radical generator.

  A conventional pressure-sensitive adhesive containing a compound having a vinyl ether group improves flexibility and improves elongation characteristics, thereby providing excellent adhesion to non-polar resins such as polyolefin as adherends (so-called interfacial adhesion). Realized. On the other hand, since the above-mentioned pressure-sensitive adhesive is insufficient in hardness, there is a problem that when an excessive stress is applied, the adherend is easily peeled off and is vulnerable to impact.

In contrast, the curable composition of the present invention is excellent in impact resistance when a nonpolar resin such as polyolefin is used as an adherend.
The reason why the curable composition of the present invention can exhibit such an effect is not clear, but the present inventor presumes as follows.

Since the curable composition of the present invention contains a vinyl ether group-containing urethane compound, a polyfunctional thiol compound, and a radical generator, it exhibits the following curing reaction.
When the curable composition of the present invention is irradiated with light or heat, radicals are generated from the radical generator. By this generated radical, an enethiol reaction between the vinyl ether group-containing urethane compound and the polyfunctional thiol compound proceeds, and a cured product having a network structure is formed. In the curable composition of this invention, since the urethane compound which has a vinyl ether group which is a reactive group with low polarity is included, the hardened | cured material which shows favorable affinity with respect to nonpolar resins, such as polyolefin, is formed. In addition, since the curable composition of the present invention contains a urethane compound having two or more vinyl ether groups in the molecule, the molecule is attracted by the urethane skeleton during the curing, and the curing shrinkage is alleviated and the curing is performed. The network structure of the object becomes dense (that is, the crosslinking density increases), and the cohesive force increases. As a result, it is considered that the curable composition of the present invention is excellent in adhesiveness.

Since the polyester resin contained in the curable composition of the present invention does not contribute to the crosslinking reaction, the network structure formed by the reaction between the vinyl ether group-containing urethane compound and the polyfunctional thiol compound has no chemical bond. It is thought that it enters.
That is, in the present invention, since the polyester resin having hardness enters the gaps in the network structure of the cured product exhibiting excellent adhesion to non-polar resins such as polyolefin, the excellent adhesion provided by the cured product is achieved. It is considered that the hardness of the cured product is increased, the shear adhesive force is improved, and excellent impact resistance can be realized without being damaged.
In addition, even if the vinyl ether group-containing urethane compound has a polyester skeleton, the above effects cannot be obtained.

<Vinyl ether group-containing urethane compound>
The curable composition of this invention contains the urethane compound (vinyl ether group containing urethane compound) which has 2 or more of vinyl ether groups in a molecule | numerator.
The vinyl ether group-containing urethane compound has two or more vinyl ether groups in the molecule, preferably 2 to 4, more preferably 2 or 3.
In the curable composition of the present invention, since the vinyl ether group-containing urethane compound has two or more vinyl ether groups which are reactive groups having low polarity in the molecule, the affinity with a nonpolar resin such as polyolefin is improved, The adhesiveness at the interface with the nonpolar resin is excellent.

  As the vinyl ether group-containing urethane compound, a urethane compound represented by the following formula (1) is preferable. The urethane compound represented by the following formula (1) has a urethane bond [—NH (CO) O—] in its structure, and has vinyl ether groups at both ends of the molecule.

In the formula (1), —X ¹ — and —X ² — are each independently —C ₄ H ₈ —, —C ₂ H ₄ —, —C ₂ H ₄ OC ₂ H ₄ —, —C ₂ H. ₄ OC ₂ H ₄ OC ₂ H ₄ —, —C ₃ H ₆ —, —C ₃ H ₆ OC ₃ H ₆ —, —C ₃ H ₆ OC ₃ H ₆ OC ₃ H ₆ —, or the following formula (2 ) Represents one of the linking groups represented by
-Z- represents a linking group represented by the following formula (3).
L represents at least one skeleton selected from an ester skeleton, a caprolactone skeleton, an ether skeleton, and a carbonate skeleton.

  The linking group represented by the formula (2) has a cyclohexyl skeleton, and the linking group represented by the formula (3) has a skeleton derived from isophorone.

  The vinyl ether group-containing urethane compound is preferably at least one urethane compound selected from a urethane compound represented by the following formula (4) and a urethane compound represented by the following formula (5).

The vinyl ether group-containing urethane compound represented by the formula (4) has a carbonate skeleton as a repeating structure in the molecule. Incidentally, ^-X 1 in the formula ^{(4) -, - X 2} -, and -Z- is, ^-X 1 in the formula ^{(1) -, - X 2} -, and -Z- synonymous.
The vinyl ether group-containing urethane compound represented by the formula (5) has an ether skeleton having 3 carbon atoms as a repeating structure in the molecule. Incidentally, ^-X 1 in the formula ^{(5) -, - X 2} -, and -Z- is, ^-X 1 in the formula ^{(1) -, - X 2} -, and -Z- as synonymous.

In Formula (4), l and n represent the number of repeating structural units. l and n each independently represent a positive integer, preferably 1 to 200, and more preferably 1 to 50 from the viewpoint of handling during synthesis.
In formula (5), m represents the number of repeating structural units. m represents a positive integer, preferably 1 to 700, and more preferably 1 to 100 from the viewpoint of handling during synthesis.

The weight average molecular weight (Mw) of the vinyl ether group-containing urethane compound is not particularly limited. For example, the weight average molecular weight (Mw) of the vinyl ether group-containing urethane compound is preferably 50,000 or less, more preferably 10,000 or less, and even more preferably 5,000 or less.
The minimum of the weight average molecular weight (Mw) of a vinyl ether group containing urethane compound is not specifically limited, For example, it is 800 or more.
When the weight average molecular weight (Mw) of the vinyl ether group-containing urethane compound is 50,000 or less, since the shear adhesive force of the cured product is further increased, the impact resistance is further improved. Moreover, since the viscosity of a vinyl ether group containing urethane compound does not become high too much, handling property is favorable.

  The weight average molecular weight (Mw) of the vinyl ether group-containing urethane compound is a value calculated by a standard polystyrene conversion method using the following gel permeation chromatography (GPC).

~conditions~
Measuring device: High-speed GPC device HLC-8220 GPC (Tosoh Corporation)
Detector: differential refractometer (RI) RI-8220 (Tosoh Corporation)
Column: TSK-GEL GMHXL (4 used) (Tosoh Corporation)
Column size: 7.8 mm ID x 30 cm
Column temperature: 40 ° C
Eluent: Tetrahydrofuran Sample concentration: 0.6 mg / mL
Injection volume: 100 μL
Flow rate: 0.8mL / min

  The curable composition of this invention may contain only 1 type of vinyl ether group containing urethane compounds, and may contain 2 or more types.

The content of the vinyl ether group-containing urethane compound in the curable composition of the present invention is preferably 15% by mass to 70% by mass and more preferably 25% by mass to 60% by mass with respect to the total solid content of the curable composition. Preferably, 35 mass%-55 mass% is still more preferable.
When the content of the vinyl ether group-containing urethane compound in the curable composition is within the above range, adhesion and cohesive force can be obtained, and impact resistance can be further improved.

(Method for synthesizing vinyl ether group-containing urethane compound)
The vinyl ether group-containing urethane compound includes at least a polyol compound having two or more hydroxy groups in the molecule (hereinafter referred to as “polyol compound” as appropriate) and an isocyanate compound having two or more isocyanate groups in the molecule (hereinafter referred to as “polyol compound”). And a monovinyl ether compound having a hydroxy group in the molecule (hereinafter, appropriately referred to as a “hydroxy group-containing monovinyl ether compound”).
The method for synthesizing the vinyl ether group-containing urethane compound is not particularly limited, and at least a polyol compound, a polyfunctional isocyanate compound, and a hydroxy group-containing monovinyl ether compound are used. If necessary, a known polymerization catalyst is used. It can be synthesized by heating and mixing in the presence.
For example, a vinyl ether group-containing urethane compound can be suitably synthesized by the following method. However, the method for synthesizing the vinyl ether group-containing urethane compound in the present invention is not limited to the following method.

A polyol compound, a polyfunctional isocyanate compound, and a polymerization catalyst such as dibutyltin dilaurate (DBTDL) are placed in a reaction vessel, and the temperature of the contents in the reaction vessel is raised to 60 ° C. and reacted for 2 hours. A polymerization catalyst and a hydroxy group-containing monovinyl ether compound are charged into the reaction vessel after the reaction, and further reacted for 2 hours to synthesize a vinyl ether group-containing urethane compound. The completion of the reaction can be confirmed by the disappearance of the 2250 cm ⁻¹ peak derived from isocyanate in the infrared absorption spectrum (IR).
Hereinafter, the polyol compound, the polyfunctional isocyanate compound, and the hydroxy group-containing monovinyl ether compound will be described in detail.

-Polyol compound-
The polyol compound in the present invention is not particularly limited as long as it is a polyol compound having two or more hydroxy groups in the molecule.
Examples of the polyol compound include polycarbonate polyol, polyoxypropylene glycol, polycaprolactone polyol, polyester polyol, polytetramethylene ether glycol, and polyoxyethylene-bisphenol A ether.
In the synthesis of the vinyl ether group-containing urethane compound, the polyol compound may be used alone or in combination of two or more.

  From the viewpoint of handling at the time of synthesis, the number of hydroxy groups that the polyol compound has in the molecule is preferably 2 to 4, and more preferably 2 or 3.

The number average molecular weight of the polyol compound is preferably less than 3,000, more preferably from 100 to 2,000, and still more preferably from 300 to 1,000.
When the number average molecular weight of the polyol compound is less than 3,000, the vinyl ether group-containing urethane compound to be synthesized is strongly attracted to molecules by the urethane skeleton in the curable composition, and the curing shrinkage is further eased. Therefore, the adhesiveness to the adherend becomes better.

The number average molecular weight (Mn) of the polyol compound is a value calculated by a standard polystyrene conversion method using the following gel permeation chromatography (GPC).
In addition, a commercial item can be used as a polyol compound as mentioned later. When the polyol compound is a commercial product, the catalog data of the commercial product is preferentially adopted.

~conditions~
Measuring device: High-speed GPC device HLC-8220 GPC (Tosoh Corporation)
Detector: differential refractometer (RI) RI-8220 (Tosoh Corporation)
Column: TSK-GEL GMHXL (4 used) (Tosoh Corporation)
Column size: 7.8 mm ID x 30 cm
Column temperature: 40 ° C
Eluent: Tetrahydrofuran Sample concentration: 0.6 mg / mL
Injection volume: 100 μL
Flow rate: 0.8mL / min

The polyol compound preferably has an alkyl group having 1 to 4 carbon atoms in the molecule. Examples of the alkyl group having 1 to 4 carbon atoms include linear chains such as a methyl group having 1 carbon atom, an ethyl group having 2 carbon atoms, and a 1-propyl group having 3 carbon atoms [— (CH ₂ ) ₂ —CH ₃ ]. In addition to the alkyl group, branched alkyl groups such as a 1-methylethyl group having 3 carbon atoms [—CH (CH ₃ ) ₂ ] can be mentioned. When the polyol compound has an alkyl group having 1 to 4 carbon atoms in the molecule, the alkyl group is more preferably a methyl group.
When the polyol compound has a methyl group in the molecule, the affinity of the curable composition with a nonpolar resin such as polyolefin is further improved, and the adhesiveness is further improved.

The polyol compound more preferably has a branched alkyl group in the molecule.
When the polyol compound has a branched alkyl group in the molecule, the affinity of the curable composition with a nonpolar resin such as polyolefin is further improved, and the adhesiveness is further improved.

As the polyol compound, commercially available products may be used.
Examples of commercially available polyol compounds include Plaxel (registered trademark) CD205PL (Mn = 500, catalog value), CD210 (Mn = 1,000, catalog value), CD220PL (Mn = 2,000, catalog value) and the like [ All are trade names, Daicel Co., Ltd.], SANNIX (registered trademark) PP-400 (Mn = 400, catalog value), PP-1000 (Mn = 1,000, catalog value), PP-2000 (Mn = 2). , 000, catalog value), etc. [all trade names, Sanyo Chemical Industries, Ltd.], Uniol (registered trademark) DA-700 [trade names, NOF Corporation, Mn = 700, catalog values], Kuraray Polyol P -510 [trade name, Kuraray Co., Ltd., Mn = 500, catalog value], Plaxel (registered trademark) 205U [trade name, Daicel Corporation, Mn = 530, Catalog value], PTMG650 [trade name, Mitsubishi Chemical Corporation, Mn = 650, catalog value] and the like.

-Polyfunctional isocyanate compound-
The polyfunctional isocyanate compound in the present invention is not particularly limited as long as it is an isocyanate compound having two or more isocyanate groups in the molecule.
Examples of the polyfunctional isocyanate compound include a diisocyanate compound having two isocyanate groups in the molecule, a triisocyanate compound having three isocyanate groups in the molecule, and a tetraisocyanate compound having four isocyanate groups in the molecule.

Examples of the diisocyanate compound include tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), xylylene diisocyanate (XDI), hydrogenated xylylene diisocyanate (H6XDI), naphthalene diisocyanate ( NDI), norbornene diisocyanate (NBDI), tetramethylxylene diisocyanate (TMXDI), dicyclohexylmethane 4,4′-diisocyanate (H12MDI), trimethylhexamethylene diisocyanate (TMDI) and the like.
Examples of the triisocyanate compound include triphenylmethane triisocyanate and 1-methylbenzole-2,4,6-triisocyanate.
Examples of the tetraisocyanate compound include dimethyltriphenylmethane tetraisocyanate.

Among these, as the polyfunctional isocyanate compound, tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, naphthalene diisocyanate, norbornene diisocyanate, tetramethylxylene diisocyanate, dicyclohexylmethane 4, At least one compound selected from 4′-diisocyanate and trimethylhexamethylene diisocyanate is preferable, the polyol compound and the hydroxy group-containing monovinyl ether compound react well, and the linear vinyl ether group-containing urethane compound is efficiently produced. From the viewpoint of synthesis, isophorone diisocyanate is more preferable.
In the synthesis of the vinyl ether group-containing urethane compound, the polyfunctional isocyanate compound may be used alone or in combination of two or more.

The polyfunctional isocyanate compound preferably has an alkyl group having 1 to 4 carbon atoms in the molecule. Examples of the alkyl group having 1 to 4 carbon atoms include linear chains such as a methyl group having 1 carbon atom, an ethyl group having 2 carbon atoms, and a 1-propyl group having 3 carbon atoms [— (CH ₂ ) ₂ —CH ₃ ]. In addition to the alkyl group, branched alkyl groups such as a 1-methylethyl group having 3 carbon atoms [—CH (CH ₃ ) ₂ ] can be mentioned. When the polyfunctional isocyanate compound has an alkyl group having 1 to 4 carbon atoms in the molecule, the alkyl group is more preferably a methyl group.
When the polyfunctional isocyanate compound has a methyl group in the molecule, the affinity of the curable composition with a nonpolar resin such as polyolefin is further improved, and the adhesiveness is further improved.
Examples of the polyfunctional isocyanate compound having a methyl group in the molecule include tolylene diisocyanate, isophorone diisocyanate, tetramethylxylene diisocyanate, trimethylhexamethylene diisocyanate, 1-methylbenzole-2,4,6-triisocyanate, dimethyltriphenylmethane tetra An isocyanate etc. are mentioned.

The polyfunctional isocyanate compound more preferably has a branched alkyl group in the molecule.
When the polyfunctional isocyanate compound has a branched alkyl group in the molecule, the affinity of the curable composition with a nonpolar resin such as polyolefin is further improved, and the adhesiveness is further improved.
Examples of the polyfunctional isocyanate compound having a branched alkyl group in the molecule include isophorone diisocyanate and dicyclohexylmethane 4,4′-diisocyanate.

  The amount of the polyfunctional isocyanate compound to be used is preferably 1.5 mol to 2.5 mol, more preferably 1.8 mol to 2.2 mol, per 1 mol of the polyol compound.

-Monovinyl ether compound containing hydroxy group-
The hydroxy group-containing monovinyl ether compound in the present invention is not particularly limited as long as it is a monovinyl ether compound having a hydroxy group in the molecule.
Examples of the hydroxy group-containing monovinyl ether compound include 2-hydroxyethyl vinyl ether (HEVE), 2-hydroxypropyl vinyl ether (HPVE), 4-hydroxybutyl vinyl ether (HBVE), 4-hydroxymethylcyclohexyl methyl vinyl ether, and diethylene glycol monovinyl ether (DEGMVE). , Triethylene glycol monovinyl ether (TEGDVE), dipropylene glycol monovinyl ether (DPGMVE) and the like.
In the synthesis of the vinyl ether group-containing urethane compound, the hydroxy group-containing monovinyl ether compound may be used alone or in combination of two or more.

The hydroxy group-containing monovinyl ether compound preferably has an alkyl group having 1 to 4 carbon atoms in the molecule. Examples of the alkyl group having 1 to 4 carbon atoms include linear chains such as a methyl group having 1 carbon atom, an ethyl group having 2 carbon atoms, and a 1-propyl group having 3 carbon atoms [— (CH ₂ ) ₂ —CH ₃ ]. In addition to the alkyl group, branched alkyl groups such as a 1-methylethyl group having 3 carbon atoms [—CH (CH ₃ ) ₂ ] can be mentioned.
When the hydroxy group-containing monovinyl ether compound has an alkyl group having 1 to 4 carbon atoms in the molecule, the alkyl group is more preferably a methyl group having 1 carbon atom.
When the hydroxy group-containing monovinyl ether compound has a methyl group in the molecule, the affinity of the curable composition with a nonpolar resin such as polyolefin is further improved, and the adhesiveness is further improved.

When the hydroxy group-containing monovinyl ether compound has a hydroxyalkyl group in the molecule, the hydroxyalkyl group may be linear or branched.
When the hydroxy group-containing monovinyl ether compound has a linear hydroxyalkyl group in the molecule, the carbon number of the carbon chain of the hydroxyalkyl group is preferably 1 to 4, more preferably 1 to 3, and 1 to 2 More preferably, 2 is particularly preferable.
When the carbon number of the carbon chain of the straight-chain hydroxyalkyl group is within the above range, the vinyl ether group-containing urethane compound to be synthesized is strongly attracted by molecules due to the urethane skeleton in the curable composition, and cured. Since the shrinkage is further eased, the adhesiveness is more excellent.

When the hydroxy group-containing monovinyl ether compound has a branched hydroxyalkyl group in the molecule, the number of carbon atoms in the hydroxyalkyl group is preferably from 3 to 6, and particularly preferably 3.
When the hydroxyalkyl group is branched, the affinity of the curable composition with a nonpolar resin such as polyolefin is further improved, and the adhesiveness is further improved.
Examples of the monovinyl ether compound having a branched hydroxyalkyl group in the molecule include 2-hydroxypropyl vinyl ether and dipropylene glycol monovinyl ether.
In addition, it is more preferable that a hydroxyl group containing monovinyl ether compound has a C1-C4 alkyl group in a molecule | numerator among a polyol compound, a polyfunctional isocyanate compound, and a hydroxyl group containing monovinyl ether compound.

  The amount of the hydroxy group-containing monovinyl ether compound to be used is preferably 1.5 mol to 2.5 mol, more preferably 1.8 mol to 2.2 mol, with respect to 1 mol of the polyol compound.

-Other ingredients-
In the method for synthesizing the vinyl ether group-containing urethane compound, other components may be used as necessary in addition to the polyol compound, the polyfunctional isocyanate compound, and the hydroxy group-containing monovinyl ether compound.
Examples of other components include a polymerization catalyst and a diluent.

Examples of the polymerization catalyst include triethylamine, tetramethylethylenediamine, triethylenediamine (TEDA), bis (N, N-dimethylamino-2-ethyl) ether, N, N, N ′, N′-tetramethylhexamethylenediamine, bis ( Examples thereof include amine catalysts such as 2-dimethylaminoethyl) ether, carboxylic acid metal salts such as potassium acetate and potassium octylate, and organometallic compounds such as dibutyltin dilaurate.
Among these, as a polymerization catalyst, dibutyltin dilaurate is preferable.
In the synthesis of the vinyl ether group-containing urethane compound, the polymerization catalyst may be used alone or in combination of two or more.

  The amount of the polymerization catalyst used is preferably 0.01 parts by mass to 0.3 parts by mass, and 0.05 parts by mass with respect to 100 parts by mass in total of the polyol compound, the polyfunctional isocyanate compound, and the hydroxy group-containing monovinyl ether compound. -0.1 mass part is more preferable.

<Multifunctional thiol compound>
The curable composition of the present invention contains a thiol compound (polyfunctional thiol compound) having two or more thiol groups in the molecule.
The polyfunctional thiol compound contributes to the curing of the curable composition of the present invention.
The curable composition of the present invention is cured by the progress of the enethiol reaction between the aforementioned vinyl ether group-containing urethane compound and the polyfunctional thiol compound.

The polyfunctional thiol compound in the present invention is not particularly limited as long as it is a thiol compound having two or more thiol groups in the molecule.
Examples of the polyfunctional thiol compound include bifunctional thiol compounds such as tetraethylene glycol bis (3-mercaptopropionate) and 1,4-bis (3-mercaptobutyryloxy) butane, trimethylolpropane tris (3-mercaptopro Pionate), tris-[(3-mercaptopropionyloxy) -ethyl] -isocyanurate, 1,3,5-tris (3-mercaptobutyryloxyethyl) -1,3,5-triazine-2,4 Trifunctional thiol compounds such as 6 (1H, 3H, 5H) -trione, trimethylolpropane tris (3-mercaptobutyrate), trimethylolethanetris (3-mercaptobutyrate), pentaerythritol tetrakis (3-mercaptopropio) Nate), pentaerythritol tetrakis (3-me Mercaptobutyrate) tetrafunctional thiol compounds such as dipentaerythritol hexakis (3-mercaptopropionate) hexafunctional thiol compound such as and the like.
Among these, as a polyfunctional thiol compound, at least 1 sort (s) chosen from a trifunctional thiol compound and a tetrafunctional thiol compound is preferable from a solvent resistant viewpoint, and a tetrafunctional thiol compound is more preferable.

A commercially available product may be used as the polyfunctional thiol compound.
As an example of a commercial product of a polyfunctional thiol compound, Karenz MT (registered trademark) BD [trade name, bifunctional thiol compound, 1,4-bis (3-mercaptobutyryloxy) butane, Showa Denko KK], Karenz MT (registered trademark) NR [trade name, trifunctional thiol compound, 1,3,5-tris (3-mercaptobutyryloxyethyl) -1,3,5-triazine-2,4,6 (1H, 3H , 5H) -trione, Showa Denko KK], Karenz MT (registered trademark) PE1 [trade name, tetrafunctional thiol compound, pentaerythritol tetrakis (3-mercaptobutyrate), Showa Denko KK], EGMP-4 [Brand name, bifunctional thiol compound, tetraethylene glycol bis (3-mercaptopropionate), SC Organic Chemical Co., Ltd.], TMMP [brand name, trifunctional All compounds, trimethylolpropane tris (3-mercaptopropionate, SC Organic Chemical Co., Ltd.), TEMPIC [trade name, trifunctional thiol compound, tris-[(3-mercaptopropionyloxy) -ethyl] -isocyanurate, SC Organic Chemical Co., Ltd.], PEMP [trade name, tetrafunctional thiol compound, pentaerythritol tetrakis (3-mercaptopropionate), SC Organic Chemical Co., Ltd.], DPMP [trade name, hexafunctional thiol compound, dipenta Erythritol hexakis, (3-mercaptopropionate), SC Organic Chemistry Co., Ltd.] and the like.

  The curable composition of this invention may contain only 1 type of polyfunctional thiol compounds, and may contain 2 or more types.

5-100 mass parts is preferable with respect to 100 mass parts of vinyl ether group containing urethane compounds, and, as for content of the polyfunctional thiol compound in the curable composition of this invention, 10 mass parts-50 mass parts are more preferable. 15 parts by mass to 35 parts by mass is more preferable.
When the content of the polyfunctional thiol compound in the curable composition is 5 parts by mass or more with respect to 100 parts by mass of the vinyl ether group-containing urethane compound, the curable composition has sufficient cross-linking points and sufficient aggregation. Since the force is obtained, the adhesiveness at the interface with the adherend becomes better.
When the content of the polyfunctional thiol compound in the curable composition is 100 parts by mass or less with respect to 100 parts by mass of the vinyl ether group-containing urethane compound, the polarity of the curable composition is increased due to the influence of the polyfunctional thiol compound. Therefore, the adhesion to nonpolar resins such as polyolefin becomes better.

In the curable composition of the present invention, the ratio between the number of equivalents of thiol groups possessed by the polyfunctional thiol compound and the number of equivalents of vinyl ether groups possessed by the vinyl ether group-containing urethane compound (number of equivalents of vinyl ether groups possessed by the vinyl ether group-containing urethane compound) : Equivalent number of thiol groups of the polyfunctional thiol compound) is preferably 1: 0.5 to 1: 1.5, more preferably 1: 0.7 to 1: 1.3, More preferably, it is 1: 0.9 to 1: 1.1.
When the ratio of the number of equivalents of thiol groups possessed by the polyfunctional thiol compound and the number of equivalents of vinyl ether groups possessed by the vinyl ether group-containing urethane compound is within the above range, the adhesive force due to the influence of unreacted polyfunctional thiol compounds And the decrease in cohesive force due to a decrease in the number of cross-linking points is suppressed, so that the adhesiveness at the interface with the adherend becomes better.

<Polyester resin>
The curable composition of the present invention contains a polyester resin.
In the curable composition of the present invention, since the polyester resin enters the gaps in the network structure formed by the enethiol reaction between the vinyl ether group-containing urethane compound and the polyfunctional thiol compound, the hardness of the cured product is increased and the impact resistance is increased. improves.

The kind of the polyester resin in the present invention is not particularly limited.
As the polyester resin, a synthetic product or a commercially available product may be used.
The polyester resin can be obtained, for example, by polycondensing these components by a known method using a dicarboxylic acid component and a diol component as raw materials.

Examples of the dicarboxylic acid component include aliphatic dicarboxylic acids such as malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, and sebacic acid, alicyclic dicarboxylic acids such as norbornene dicarboxylic acid and cyclohexanedicarboxylic acid, terephthalic acid, and isophthalic acid. , Dicarboxylic acids such as aromatic dicarboxylic acids such as phthalic acid and 1,4-naphthalenedicarboxylic acid or ester derivatives thereof.
In the synthesis of the polyester resin, the dicarboxylic acid component may be used alone or in combination of two or more.

Examples of the diol component include aliphatic diols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, and 1,3-butanediol; alicyclic diols such as cyclohexanedimethanol And diol compounds such as aromatic diols such as bisphenol A, 1,3-benzenedimethanol and 1,4-benzenedimethanol.
In the synthesis of the polyester resin, the diol component may be used alone or in combination of two or more.

The polyester resin may be an unmodified polyester resin or a modified polyester resin.
Examples of the modified polyester resin include a chlorinated polyester resin obtained by reacting a polyester resin with chlorine, a polyester resin obtained by adding an acryloyl group to a polyester skeleton (so-called polyester acrylate), and the like.
For example, a chlorinated polyester resin is preferable because it can increase the shear adhesive strength of the curable composition in a relatively small amount.

The weight average molecular weight (Mw) of the polyester resin is not particularly limited.
For example, the weight average molecular weight (Mw) of the polyester resin is preferably 400 or more and 100,000 or less, more preferably 700 or more and 50,000 or less, and still more preferably 1,000 or more and 10,000 or less.
When the weight average molecular weight (Mw) of the polyester resin is 400 or more, it enters the gaps in the network structure formed by the enethiol reaction between the vinyl ether group-containing urethane compound and the polyfunctional thiol compound. The impact will be better.
When the weight average molecular weight (Mw) of the polyester resin is 100,000 or less, the compatibility with other components is good, so that the impact resistance is more excellent.

  The weight average molecular weight (Mw) of the polyester resin is a value calculated by the same method as the weight average molecular weight (Mw) of the above-described vinyl ether group-containing urethane compound.

  Examples of commercially available polyester resins include EBECRYL (registered trademark) 436 [trade name, chlorinated polyester / trimethylolpropane triacrylate (mass ratio) = 60/40, weight average molecular weight: 5,000, Daicel Ornex ( EBECRYL (registered trademark) 438 [trade name, chlorinated polyester / glycerin propoxytriacrylate (mass ratio) = 60/40, weight average molecular weight: 5,000, Daicel Ornex Co., Ltd.], EBECRYL (registered) Trademark) 800 [trade name, polyester acrylate, weight average molecular weight: 780, Daicel Ornex Co., Ltd.], EBECRYL (registered trademark) 446 [trade name, chlorinated polyester / trimethylolpropane triacrylate (mass ratio) = 68 / 32, weight average molecular weight: 4, 00, Daicel Ornex Co., Ltd.], EBECRYL (registered trademark) 524 [trade name, polyester / 1,6-hexanediol diacrylate (mass ratio) = 70/30, weight average molecular weight: 1,000, Daicel Ornex Co., Ltd.], EBECRYL (registered trademark) 525 [trade name, polyester / dipropylene glycol diacrylate (mass ratio) = 60/40, weight average molecular weight: 40,000, Daicel Ornex Co., Ltd.] and the like. .

  The curable composition of this invention may contain only 1 type of polyester resins, and may contain 2 or more types.

The content of the polyester resin in the curable composition of the present invention is preferably 10 parts by mass or more and 300 parts by mass or less, more preferably 15 parts by mass or more and 240 parts by mass with respect to 100 parts by mass of the vinyl ether group-containing urethane compound. Part or less, more preferably 15 parts by weight or more and 60 parts by weight or less.
When the content of the polyester resin in the curable composition is 10 parts by mass or more with respect to 100 parts by mass of the vinyl ether group-containing urethane compound, the polyester resin that ensures the hardness is sufficiently contained. Improves impact resistance.
When the content of the polyester resin in the curable composition is 300 parts by mass or less with respect to 100 parts by mass of the vinyl ether group-containing urethane compound, the polyester resin ensuring the hardness ensures the affinity with the adherend. Since there are not too many with respect to the vinyl ether group containing urethane compound to be performed, it becomes the curable composition which is excellent by the balance of the adhesiveness and impact resistance in an interface.

<Radical generator>
The curable composition of the present invention contains a radical generator.
The curable composition of the present invention is cured by an enethiol reaction between the vinyl ether group-containing urethane compound and the polyfunctional thiol compound by radicals generated from the radical generator.

  The radical generator is not particularly limited, and those known to those skilled in the art can be used without limitation. Examples of the radical generator include a thermal radical generator (thermal polymerization initiator), a redox initiator, and a photo radical generator (photopolymerization initiator).

  Examples of the thermal radical generator include benzoyl peroxide, lauroyl peroxide, caproyl peroxide, di-n-propyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, t-butyl peroxypivalate, t- Organic peroxides such as butylperoxy-2-ethylhexanate, 2,2′-azobis-isobutyronitrile, 2,2′-azobis-2,4-dimethylvaleronitrile, 2,2′-azobis- Examples include azo compounds such as 4-methoxy-2,4-dimethylvaleronitrile.

  Redox initiators include Permec N [trade name, methyl ethyl ketone peroxide, NOF Co., Ltd.] and cobalt naphthenate, Parkmill H [trade name, cumene hydroperoxide, NOF Corporation] and pentoxide. Combination with vanadium, Niper BMT [trade name, di (3-methylbenzoyl) peroxide + benzoyl (3-methylbenzoyl) peroxide + dibenzoyl peroxide, NOF Corporation] and dimethylaniline, niper A combination of PMB [trade name, di (4-methylbenzoyl) peroxide, NOF Corporation] and dimethylaniline, NIPPER BW [trade name, dibenzoyl peroxide, NOF Corporation] and dimethylaniline. A combination etc. are mentioned.

Examples of the photoradical generator include benzoin derivative compounds, benzyl ketal compounds, α-hydroxyacetophenone compounds, thioxanthone compounds, acylphosphine oxide compounds, and the like.
Specifically, as a photo radical generator, 1-hydroxycyclohexyl phenyl ketone [trade name: Irgacure 184, BASF Japan Ltd.], 2-hydroxy-2-methyl- [4- (1-methylvinyl) phenyl ] Propanol oligomer [trade name: Esacure ONE, Lambarty Co., Ltd.], 1- [4- (2-hydroxyethoxy) phenyl] -2-hydroxy-2-methyl-1-propan-1-one [trade name: Irgacure 2959, BASF Japan Ltd.], 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] -phenyl} -2-methyl-propan-1-one [Commodity Name: Irgacure 127, BASF Japan Ltd.], 2,2-dimethoxy-2-phenylacetophenone [trade] Name: Irgacure 651, BASF Japan Ltd.], 2-hydroxy-2-methyl-1-phenyl-propan-1-one [trade name: Darocur 1173, BASF Japan Ltd.], 2-methyl-1- [ (4-Methylthio) phenyl] -2-morpholinopropan-1-one [trade name: Irgacure 907, BASF Japan Ltd.], 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone -1,2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diisopropylthioxanthone, isopropylthioxanthone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) phenyl Phosphine oxide, bis (2,6-dimetho Shibenzoiru) -2,4,4-trimethyl pentyl phosphine oxide and the like.

  Among these, as the radical generator, a photoradical generator is preferable from the viewpoint of easy operation. Further, as the photo radical generator, an α-hydroxyacetophenone compound is preferable from the viewpoint that the compatibility with the vinyl ether group-containing urethane compound is good, the yellowing of the curable composition hardly occurs, and the smell is small. 1-hydroxycyclohexyl phenyl ketone is particularly preferred.

  The curable composition of the present invention may contain only one type of radical generator, or may contain two or more types.

When the curable composition of the present invention contains a photo radical generator as a radical generator, the content of the photo radical generator in the curable composition is a vinyl ether group-containing urethane compound, a polyfunctional thiol compound, and a vinyl ether group containing 0.1 to 20 parts by mass is preferable, 0.5 to 10 parts by mass is more preferable, and 1 to 5 parts by mass with respect to 100 parts by mass in total with the compound having an ethylenically unsaturated bond other than the urethane compound. 7 parts by mass is more preferable.
The content of the photo radical generator in the curable composition is 0 with respect to 100 parts by mass in total of the vinyl ether group-containing urethane compound, the polyfunctional thiol compound, and the compound having an ethylenically unsaturated bond other than the vinyl ether group-containing urethane compound. When the amount is 1 part by mass or more, photocuring of the curable composition proceeds sufficiently during light irradiation, so that poor curing hardly occurs.
The content of the photo radical generator in the curable composition is 100 parts by mass in total of the vinyl ether group-containing urethane compound, the polyfunctional thiol compound, and the compound having an ethylenically unsaturated bond other than the vinyl ether group-containing urethane compound. When the amount is 20 parts by mass or less, the photoradical generator does not absorb light excessively, so that the curing failure of the curable composition hardly occurs. In addition, the photo radical generator hardly precipitates over time, and the storage stability of the curable composition becomes better.

<Other ingredients>
The curable composition of the present invention includes other components other than the vinyl ether group-containing urethane compound, the polyfunctional thiol compound, the polyester resin, and the radical generator, as necessary, within a range not impairing the effects of the present invention. May be.
Other components include compounds having ethylenically unsaturated bonds other than vinyl ether group-containing urethane compounds, polymerization inhibitors, sensitizers, antioxidants, flame retardants, antistatic agents, leveling agents, antifoaming agents, Various additives such as pigments may be mentioned.

  Examples of the compound having an ethylenically unsaturated bond other than the vinyl ether group-containing urethane compound include polyfunctional acrylates having two or more acryloyl groups. Examples of such polyfunctional acrylates include 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, neopentyl glycol diacrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate, and polytetraethylene glycol diacrylate. Acrylate, tricyclodecane dimethanol diacrylate, ethoxylated bisphenol A diacrylate, alkoxylated glycerin triacrylate, trimethylolpropane triacrylate, alkoxylated trimethylolpropane triacrylate, pentaerythritol triacrylate, alkoxylated pentaerythritol triacrylate, glycerin Propoxy triacrylate, pentaerythritol tetraacrylate Alkoxylated pentaerythritol tetraacrylate, ditrimethylolpropane tetraacrylate, and dipentaerythritol hexaacrylate.

  As polymerization inhibitors, methylhydroquinone, t-butylhydroquinone, 4-methoxynaphthol, 1,4-benzoquinone, methoquinone, dibutylhydroxytoluene, N-nitrosophenylhydroxylamine aluminum salt, 1,4-naphthoquinone, 4-hydroxy -2,2,6,6-tetramethylpiperidine 1-oxyl (4-hydroxy TEMPO) and the like.

[Use]
The curable composition of the present invention can be suitably used as an adhesive because it exhibits a high shear adhesive strength of, for example, 1 MPa or more and is excellent in impact resistance. The curable composition of the present invention is excellent not only in polar substances such as metal, glass, ceramics, wood, and ceramics, but also in impact resistance when a nonpolar resin is used as an adherend. It can be suitably used for adhesion.

The curable composition of this invention can be used suitably for adhesion | attachment of a polar substance and nonpolar resin, and adhesion | attachment of nonpolar resins.
Moreover, the curable composition of this invention can be used suitably as adhesives, such as a label of various goods, a sticker. When the curable composition of the present invention is used as an adhesive for labels, stickers, etc. of various products, for example, the curable composition of the present invention on various resin films made of olefin resin, acrylic resin, etc. , And after the application surface is bonded to various adherends, the label, the sticker, and the like can be adhered to the product as the adherend by irradiating light.

  Hereinafter, the present invention will be described more specifically with reference to examples. The present invention is not limited to the following examples as long as the gist thereof is not exceeded.

  The weight average molecular weight (Mw) of the urethane compound produced in this example was measured by the method described above.

-Production of urethane compounds-
[Production Example 1]
In a reaction vessel equipped with a thermometer, a stirrer, and a reflux condenser, Sanix (registered trademark) PP-400 (polyoxypropylene glycol (m = 7) represented by the following structural formula (a), number average) 100 parts by mass of molecular weight (Mn) = 400 (catalog value), Sanyo Chemical Industries, Ltd., 112 parts by mass of isophorone diisocyanate (IPDI) and 0.03 parts by mass of dibutyltin dilaurate (DBTDL) were added and stirred. The temperature of the contents of the reaction vessel was raised to 60 ° C. and reacted for 2 hours. Thereafter, 0.20 part by mass of dibutyltin dilaurate (DBTDL) and 56 parts by mass of 4-hydroxybutyl vinyl ether (HBVE) are added, and the reaction is further performed for 2 hours, and a urethane compound having vinyl ether groups at both ends of the molecular chain. (Hereinafter referred to as “vinyl ether urethane compound (A)”). The completion of the reaction was confirmed by the disappearance of the 2250 cm ⁻¹ peak derived from isocyanate in the infrared absorption spectrum (IR).
It was 2,200 when the weight average molecular weight (Mw) of the obtained vinyl ether urethane compound (A) was measured.
Incidentally, vinyl urethane compound (A) is a compound represented by the above formula (5), -X ¹ in the formula (5) is _-C 4 _{H 8} - and is, -X ² is - C ₄ H ₈ —, —Z— is a linking group represented by Formula (3), and m is 7.

[Production Example 2]
In a reaction vessel equipped with a thermometer, a stirrer, and a reflux condenser, Sanix (registered trademark) PP-400 (polyoxypropylene glycol (m = 7) represented by the structural formula (a) described above, Average molecular weight (Mn) = 400 (catalog value), Sanyo Chemical Industries, Ltd.) 100 parts by mass, isophorone diisocyanate (IPDI) 112 parts by mass, and dibutyltin dilaurate (DBTDL) 0.03 parts by mass are stirred. The temperature of the contents of the reaction vessel was raised to 60 ° C. and reacted for 2 hours. Thereafter, 0.20 parts by mass of dibutyltin dilaurate (DBTDL) and 43 parts by mass of 2-hydroxyethyl vinyl ether (HEVE) were added, and the reaction was further continued for 2 hours, and a urethane compound having vinyl ether groups at both ends of the molecular chain. (Hereinafter referred to as “vinyl ether urethane compound (B)”). The completion of the reaction was confirmed by the disappearance of the 2250 cm ⁻¹ peak derived from isocyanate in the infrared absorption spectrum (IR).
It was 2,100 when the weight average molecular weight (Mw) of the obtained vinyl ether urethane compound (B) was measured.
Incidentally, vinyl urethane compound (B) is a compound represented by the above formula (5), -X ¹ in the formula (5) is _-C 2 _{H 4} - a and, -X ² is - C ₂ H ₄ —, —Z— is a linking group represented by Formula (3), and m is 7.

[Production Example 3]
In a reaction vessel equipped with a thermometer, a stirrer, and a reflux condenser, Plaxel (registered trademark) 205U (polycaprolactone diol (1, n = 2) represented by the following structural formula (c), number average molecular weight ( Mn) = 530 (catalog value), Daicel Co., Ltd.) 100 parts by mass, isophorone diisocyanate (IPDI) 89 parts by mass, and dibutyltin dilaurate (DBTDL) 0.03 part by mass. The temperature of the contents was raised to 60 ° C. and reacted for 2 hours. Thereafter, 0.16 parts by mass of dibutyltin dilaurate (DBTDL) and 44 parts by mass of 4-hydroxybutyl vinyl ether (HBVE) were added, and further reacted for 2 hours to have a polyester skeleton and both molecular chains. A urethane compound having a vinyl ether group at the terminal (hereinafter referred to as “vinyl ether urethane compound (C)”) was obtained. The completion of the reaction was confirmed by the disappearance of the 2250 cm ⁻¹ peak derived from isocyanate in the infrared absorption spectrum (IR).
It was 2,900 when the weight average molecular weight (Mw) of the obtained vinyl ether urethane compound (C) was measured.

-Production of curable composition-
[Example 1]
100 parts by mass of the vinyl ether urethane compound (A) obtained in Production Example 1 above and Irgacure (registered trademark) 184 which is a radical generator [photo radical generator, 1-hydroxycyclohexyl phenyl ketone, BASF Japan Ltd. )] 3.75 parts by weight were weighed into a brown sample bottle, heated at 60 ° C. for 20 minutes, and then stirred with a spatula for 5 minutes. Next, in the brown sample bottle after stirring, EBECRYL (registered trademark) 438 which is a polyester resin [chlorinated polyester / glycerin propoxytriacrylate (mass ratio) = 60/40, weight average molecular weight: 5,000, Daicel Ornex Co., Ltd.] 25 parts by mass and Karenz MT (registered trademark) PE1 which is a polyfunctional thiol compound [thiol compound having four thiol groups in the molecule (tetrafunctional thiol compound), pentaerythritol tetrakis (3-mercaptobutyrate) ), Showa Denko Co., Ltd.] 22.4 parts by mass, heated at 40 ° C. for 10 minutes, and then stirred and mixed with a spatula for 5 minutes to obtain the curable composition of Example 1.

[Examples 2 to 7]
Except having changed the composition of the curable composition into the composition shown in following Table 1, operation similar to Example 1 was performed and the curable composition of Examples 2-7 was obtained.

[Comparative Examples 1-8]
Except having changed the composition of the curable composition into the composition shown in Table 2 below, the same operations as in Example 1 were performed to obtain the curable compositions of Comparative Examples 1 to 8.

<Measurement of shear adhesive strength>
As an index for evaluating the impact resistance of the curable composition, shear adhesive strength was measured.
Two 25 mm-wide polypropylene plates (hereinafter referred to as “PP plates”) [trade name: PP-N-BN, Partec Co., Ltd.] were prepared.
Each of the curable compositions of Examples 1 to 7 and Comparative Examples 1 to 8 was applied on a PP plate using an applicator so that the thickness after application was 30 μm, and another sheet was applied on the application surface. The PP plate was laminated to prepare a sheet having a configuration of PP plate / curable composition / PP plate. Next, the sheet was irradiated with light under the conditions of an illuminance of 150 mW / cm ² and an integrated light amount of 500 mJ / cm ² to cure the curable composition to obtain a test piece.
This test piece was applied to the adhesive surface using a tensile tester (model number: RTF-1350, A & D Co., Ltd.) under the conditions of 23 ° C., 50% RH and a tensile speed of 10 mm / min. On the other hand, it was pulled at a constant speed in parallel, and a load was applied to break the bonded portion, and the shear adhesive force (unit: MPa, maximum load when the bonded portion was broken) was measured. The time until the bonded portion broke was about 5 seconds.
If the shear adhesive strength is 1 MPa or more, it means that the impact resistance is excellent.

Table 1 shows the compositions of the curable compositions of Examples 1 to 7 and the measurement results of the shear adhesive strength. In addition, Table 2 shows the compositions of the curable compositions of Comparative Examples 1 to 8 and the measurement results of the shear adhesive strength.
In Tables 1 and 2, “-” means that the corresponding component is not blended.

The detail of the component in said Table 1 and Table 2 is as follows.
<Vinyl ether urethane compound>
(A): Vinyl ether urethane compound obtained in Production Example 1 above (B): Vinyl ether urethane compound obtained in Production Example 2 above (C): Vinyl ether urethane compound obtained in Production Example 3 <Polyester Resin>
EBECRYL (registered trademark) 438: chlorinated polyester / glycerin propoxytriacrylate (OTA480) (mass ratio) = 60/40, weight average molecular weight: 5,000, Daicel Ornex Co., Ltd.
EBECRYL (registered trademark) 436: chlorinated polyester / trimethylolpropane triacrylate (mass ratio) = 60/40, weight average molecular weight: 5,000, Daicel Ornex Corporation
EBECRYL (registered trademark) 800: polyester acrylate, weight average molecular weight: 780, Daicel Ornex Co., Ltd.

<Multifunctional acrylate>
OTA480: glycerin propoxytriacrylate, weight average molecular weight: 480, Daicel Ornex Corporation
<Modified epoxy acrylate>
EBECRYL (registered trademark) 3708: weight average molecular weight: 1,500, Daicel Ornex Co., Ltd.
<Multifunctional thiol compound>
Karenz MT (registered trademark) PE1: thiol compound having four thiol groups in the molecule (tetrafunctional thiol compound), pentaerythritol tetrakis (3-mercaptobutyrate), Showa Denko K.K.
<Radical generator>
Irgacure (registered trademark) 184: photo radical generator, 1-hydroxycyclohexyl phenyl ketone, BASF Japan Ltd.

As shown in Table 1, a urethane compound having two or more vinyl ether groups in the molecule (vinyl ether group-containing urethane compound), a thiol compound having two or more thiol groups in the molecule (polyfunctional thiol compound), a polyester resin, and It was suggested that the curable compositions of Examples 1 to 7 containing a radical generator exhibited sufficiently high shear adhesive strength and excellent impact resistance.
On the other hand, as shown in Table 2, the curable compositions of Comparative Examples 1 to 6 and 8 that do not contain at least one of the vinyl ether group-containing urethane compound, the polyfunctional thiol compound, and the polyester resin are curable in the examples. Compared with the composition, it was suggested that the shear adhesive strength was low and the impact resistance was poor. In addition, the curable composition of the comparative example 7 which does not contain a polyfunctional thiol compound did not harden | cure even if irradiated with light, and could not measure shear adhesive force.

In the curable composition of Comparative Example 4 which did not contain a polyester resin and contained an acrylic resin, an improvement in shear adhesion was recognized, but a shear adhesion exceeding 1 MPa was not obtained.
It was suggested that the curable composition of Comparative Example 5 containing a vinyl ether group-containing urethane compound having a polyester skeleton and no polyester resin has low shear adhesion and is inferior in impact resistance.
According to the contrast of the curable compositions of Example 2, Comparative Example 1 and Comparative Example 3, the high shear adhesion observed in the curable composition of Example 2 is included in EBECRYL® 438. It was revealed that it was not caused by glycerin propoxytriacrylate, but was caused by chlorinated polyester.

Claims (6)

  A curable composition comprising a urethane compound having two or more vinyl ether groups in the molecule, a thiol compound having two or more thiol groups in the molecule, a polyester resin, and a radical generator. The curable composition according to claim 1, wherein the urethane compound is a compound represented by the following formula (1).

Wherein, -X ¹ - and -X ² - are each _{independently, -C 4 H 8 -, -} C 2 H 4 -, - C 2 H 4 OC 2 H 4 -, - C 2 H 4 OC ₂ H ₄ OC ₂ H ₄ —, —C ₃ H ₆ —, —C ₃ H ₆ OC ₃ H ₆ —, —C ₃ H ₆ OC ₃ H ₆ OC ₃ H ₆ —, or the following formula (2) Represents any of the represented linking groups. -Z- represents a linking group represented by the following formula (3). L represents at least one skeleton selected from an ester skeleton, a caprolactone skeleton, an ether skeleton, and a carbonate skeleton. ]

  The content of the said polyester resin in a curable composition is 15 mass parts or more and 240 mass parts or less with respect to 100 mass parts of said urethane compounds, The curable composition of Claim 1 or Claim 2.   The curable composition according to any one of claims 1 to 3, wherein the polyester resin is a chlorinated polyester resin.   The weight average molecular weight of the said polyester resin is 400 or more and 100,000 or less, The curable composition of any one of Claims 1-4.   The curable composition according to any one of claims 1 to 5, which is used for adhesion to an olefin resin.