JP2023125582A - Curable composition, self-healing material and cured product - Google Patents

Abstract

To provide a self-healing curable material free of sulfur atoms.SOLUTION: A curable composition according to one embodiment of the present invention includes (A) a monofunctional vinyl monomer, (B) a polyfunctional vinyl monomer including two or more vinyl groups and a boronic ester group or a borinic ester group in one molecule, and (C) a polymerization initiator.SELECTED DRAWING: None

Description

The present invention relates to a curable composition, a self-healing material, and a cured product.

Curable materials are used in applications such as adhesives, sealants, and paints. If the cured product obtained by curing the above-mentioned curable material is damaged or broken, it will no longer be possible to obtain the intended effect, so there has been a demand for a material with a longer lifespan.

Patent Document 1 describes a composition having self-healing properties as a curable material. Even if these materials break, their self-repairing ability allows them to repair the broken part, so they are attracting attention as a technology that can extend the lifespan of the materials.

International Publication No. 2020/175321

However, the prior art as described above contains a disulfide bond and has room for further improvement in that its use is limited by the properties of the sulfur atom.

One aspect of the present invention is to provide a self-healing curable material that does not contain sulfur atoms.

In order to solve the above problems, a curable composition according to one embodiment of the present invention,
(A) monofunctional vinyl monomer,
(B) a polyfunctional vinyl monomer having two or more vinyl groups and a boronic acid ester group or a boric acid ester group in one molecule, and
(C) Contains a polymerization initiator.

According to one aspect of the present invention, a self-healing curable material that does not contain sulfur atoms can be provided.

Hereinafter, an example of an embodiment of the present invention will be described in detail, but the present invention is not limited thereto.

Unless otherwise specified herein, the numerical range "A to B" means "A or more and B or less". As used herein, "(meth)acrylic" means "acrylic" and/or "methacrylic".

[1. Summary of the invention]
A conventional composition having self-healing properties as a curable material as described in Patent Document 1 uses a disulfide bond containing a sulfur atom as a group for driving the self-healing function. In addition to being harmful to the human body, sulfur oxides may corrode metals or poison metal catalysts. Therefore, depending on the application, the use may be restricted due to concerns about the adverse effects of sulfur atoms. Therefore, there is a need for a self-healing curable material that can be used widely and generally without being restricted in its use as described above.

Therefore, the inventors of the present invention have conducted intensive studies on means to solve the above problems, and have discovered that a self-healing curable material that does not contain sulfur atoms can be obtained by using the following curable composition. .

[2. Curable composition]
Specifically, the curable composition according to one embodiment of the present invention includes (A) a monofunctional vinyl monomer, (B) two or more vinyl groups and a boronic acid ester group or borin in one molecule. A polyfunctional vinyl monomer having an acid ester group, and (C) a polymerization initiator.

[2-1. (A) Monofunctional vinyl monomer]
In this specification, the monofunctional vinyl monomer (A) is a vinyl monomer having one vinyl group in one molecule. In addition, in this specification, a "vinyl group" also includes the case where it is substituted with an alkyl group or the like (for example, a methyl group). Hereinafter, the monofunctional vinyl monomer (A) will also be referred to as "component (A)."

Examples of component (A) include linear or cyclic (meth)acrylate monomers, (meth)acrylic acid, styrene monomers, conjugated diene monomers, acrylonitrile, vinyl chloride, N-vinylpyrrolidone, acrylamide monomers, Examples include vinyl ketone monomers and vinyl ester monomers. These may be used alone or in combination of two or more.

Specific examples of component (A) that are preferred from the viewpoint of good physical properties of the obtained cured product and easy adjustment of the viscosity of the curable composition include (meth)acrylic acid, methyl (meth)acrylate, and ethyl (meth)acrylate. ) acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, nonyl (meth)acrylate ) acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate , octadecyl (meth)acrylate, cyclohexyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, isononyl (meth)acrylate, isobornyl (meth)acrylate, adamantyl (meth)acrylate, 2- Examples include hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, (meth)acrylamide, diethylaminoethyl (meth)acrylate, N-vinylpyrrolidone, N-vinylformamide, acryloylmorpholine, and the like. Among these, from the viewpoint of availability, isononyl (meth)acrylate, dodecyl (meth)acrylate, octadecyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, isobornyl (meth)acrylate, Preferred are acrylate, adamantyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and acryloylmorpholine. When isomers exist in the alkyl group or alicyclic group of component (A), any of the isomers can be used in the same manner, and a mixture thereof may also be used.

Component (A) also includes, for example, monofunctional oligomers having a relatively large molecular weight. Such monofunctional oligomers are also called macromonomers or macromers. As the monofunctional oligomer, for example, a (meth)acryloyl group-containing oligomer can be used. Examples of (meth)acryloyl group-containing oligomers include compounds having an oligomer skeleton consisting of a repeating monomer structure and an average of 0.5 to 1.0 (meth)acryloyl groups in one molecule. .

Examples of the oligomer skeleton constituting the main chain include polybutadiene, hydrogenated polybutadiene, polyisoprene, hydrogenated polyisoprene, polyisobutylene, polyether, polyester, polycarbonate, polyacrylate, epoxy compound polymer, silicone polymer, etc. can be mentioned.

Among these, if physical properties such as rubber physical properties, tackiness, adhesion, gas barrier properties, vibration damping properties, heat resistance, and chemical resistance are important, polybutadiene, hydrogenated polybutadiene, polyisoprene, hydrogenated polyisoprene, poly Preferably, a polyolefin-based oligomer skeleton such as isobutylene is selected.

On the other hand, if physical properties such as viscosity, handleability, compatibility with other components, tackiness, adhesion, durability, and heat resistance are important, polymers of polyether, polyester, polycarbonate, polyacrylate, and epoxy compounds, It is preferable to select an oligomer skeleton selected from silicone polymers.

There is no particular limit to the number average molecular weight of the (meth)acryloyl group-containing oligomer, but it is determined based on availability, compatibility with other components of the curable composition, ease of developing properties derived from the oligomer skeleton, and the curable composition. Since the curable composition is easy to handle, it is preferably from 200 to 500,000, more preferably from 1,000 to 100,000.

The (meth)acryloyl group-containing oligomers may be used alone or in combination of two or more. It may also be used in combination with other monofunctional vinyl monomers. In particular, when two or more types of (meth)acryloyl group-containing oligomers are used together, it is preferable to also use a monofunctional vinyl monomer in order to ensure compatibility of each component.

Among these, polybutadiene, hydrogenated polybutadiene, polyisoprene, hydrogenated polyisoprene, polyisobutylene, polyether, Compounds containing an oligomer skeleton selected from the group consisting of polyacrylates, polymers of epoxy compounds, and silicone polymers are preferred.

[2-2. (B) Polyfunctional vinyl monomer]
In this specification, the polyfunctional vinyl monomer (B) is a vinyl monomer having two or more vinyl groups in one molecule. Hereinafter, the polyfunctional vinyl monomer (B) will also be referred to as "component (B)." The upper limit of the number of vinyl groups in one molecule of component (B) is not particularly limited, but may be, for example, 10. Since component (B) serves as a crosslinking point, it preferably has 4 to 10 vinyl groups if a cured product with high hardness and strength is desired. On the other hand, if it is desired to obtain a cured product with excellent flexibility and elongation, it is preferable to have 2 to 3 vinyl groups. From the viewpoint of availability of component (B) and ease of synthesis, it is preferable that component (B) has two vinyl groups. Component (B) may have a vinyl group as a part of the (meth)acryloyl group. That is, component (B) may have two or more (meth)acryloyl groups in one molecule.

Component (B) has a boronic acid ester group or a boric acid ester group. In this specification, a boronic acid ester group means a group represented by "-B(OR) ₂ ", and a boric acid ester group means a group represented by "-B(OR)R". . Here, each R independently represents an organic group. The organic group may be an alkyl group or an aryl group. Two ORs in the boronic acid ester group may form a ring structure. For example, component (B) may have a dioxaborolane structure as such a ring structure. As used herein, the dioxaborolane structure means a 5-membered ring represented by the formula C-O-B-O-C (where the Cs at both ends are bonded to each other).

Moreover, it is preferable that the component (B) has two or more boron elements in one molecule. (B) The upper limit of the number of boron elements in one molecule of the polyfunctional vinyl monomer is not particularly limited, but may be, for example, 10. Elemental boron may be present as part of a boronic acid ester group or a boric acid ester group. Component (B) may have two or more boronic acid ester groups in one molecule, or may have two or more boric acid ester groups, and a boronic acid ester group and a boric acid ester group It may also have an ester group.

In component (B), a transesterification reaction occurs at the borinic acid ester group or the boronic acid ester group, and it is thought that self-healing properties are developed. In other words, by using a boric acid ester group or a boronic acid ester group, transesterification is possible, unlike "B(OR) ₃ " in which all three bonds of the boron element are bonded to the oxygen element. It is possible to clarify the location where self-healing occurs and the location where self-repairing properties are expressed.

Examples of the compound of component (B) having a boronic acid ester group include a compound represented by the following general formula (1).

(R ¹ is a divalent organic group, R ² to R ⁴ are each independently hydrogen or a monovalent hydrocarbon group, R ⁵ is a divalent organic group, R ⁶ to R ⁸ are each independently hydrogen or (Represents a methyl group.)
R ¹ is not particularly limited as long as it is a divalent organic group, for example, it may be a divalent organic group having 1 to 20 carbon atoms, or a divalent hydrocarbon group having 1 to 20 carbon atoms. More specifically, examples thereof include alkylene groups such as methylene group, ethylene group, propylene group, butylene group, pentylene group, and hexylene group, and divalent aromatic groups such as phenylene group and naphthylene group. When R ² to R ⁴ are monovalent hydrocarbon groups, they are preferably monovalent hydrocarbon groups having 1 to 10 carbon atoms, such as methyl group, ethyl group, propyl group, butyl group, pentyl group. , an alkyl group such as a hexyl group, and the like. R ⁵ is not particularly limited as long as it is a divalent organic group, for example, it may be a divalent organic group having 1 to 10 carbon atoms, or a divalent hydrocarbon group having 1 to 10 carbon atoms. More specifically, alkylene groups such as methylene group, ethylene group, propylene group, butylene group, pentylene group, and hexylene group can be mentioned. When isomers exist in R ¹ to R ⁵ , any of the isomers can be used in the same manner.

As a specific example of the above general formula (1), a compound represented by the following formula (2,2'-(1,4-phenylene)-bis[4-(acryloyloxymethyl)-1,3,2-dioxaborolane] ).

The blending amount of component (B) is preferably 0.1 to 100 parts by weight, more preferably 1 to 60 parts by weight, and 3 to 20 parts by weight based on 100 parts by weight of component (A). It is more preferable that

[2-3. (C) Polymerization initiator]
As used herein, (C) a polymerization initiator is a compound that generates active species (for example, radical species) that can initiate polymerization of monomers upon external stimulation such as light or heat. These compounds are not particularly limited, but include known photo radical polymerization initiators and thermal radical polymerization initiators. Hereinafter, the polymerization initiator (C) is also referred to as "component (C)." Examples of the component (C) include compounds described in International Publication No. 2013/047314 and JP2013-216782. Among these, as the photoradical polymerization initiator, (a) a compound having a hydroxyl group and a phenyl ketone structure, (b) a compound having a benzophenone structure, and (c) a compound having an acylphosphine oxide structure, etc. are preferably used. I can do it. As the thermal radical polymerization initiator, (d) an azo initiator, (e) a peroxide, (f) a persulfate, and (g) a redox initiator can be preferably used.

(a) Compounds having a hydroxyl group and a phenyl ketone structure include 2,2-dimethoxy-1,2-diphenylethan-1-one, 1-hydroxy-cyclohexyl-phenyl ketone, 2-hydroxy-2-methyl-1 -Phenyl-propan-1-one, and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanon-1-one, 2-methyl-1-[4-(methylthio)phenyl]- Examples include 2-morpholinopropan-1-one.

(b) Compounds having a benzophenone structure include benzophenone, 3-methoxybenzophenone, 4-methylbenzophenone, 4,4'-bis(diethylamino)benzophenone, 4-chlorobenzophenone, 4,4'-dimethoxybenzophenone, and -chloro-4'-benzylbenzophenone and the like.

(c) Compounds having an acylphosphine oxide structure include bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, and 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide.

(d) As the azo initiator, 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile) (VAZO 33), 2,2'-azobis(2-amidinopropane) dihydrochloride ( VAZO 50), 2,2'-azobis(2,4-dimethylvaleronitrile) (VAZO 52), 2,2'-azobis(isobutyronitrile) (VAZO 64), 2,2'-azobis-2- Methylbutyronitrile (VAZO 67), 1,1-azobis(1-cyclohexanecarbonitrile) (VAZO 88), 2,2'-azobis(2-cyclopropylpropionitrile), and 2,2'-azobis( Methyl isobutyrate) (V-601) and the like.

(e) Peroxides include benzoyl peroxide, acetyl peroxide, lauroyl peroxide, decanoyl peroxide, dicumyl peroxide, dicetyl peroxydicarbonate, t-butylperoxyisopropyl monocarbonate, di(4-t -butylcyclohexyl) peroxydicarbonate, di(2-ethylhexyl)peroxydicarbonate, t-butylperoxypivalate, and t-butylperoxy-2-ethylhexanoate.

(f) Examples of persulfates include potassium persulfate, sodium persulfate, ammonium persulfate, sodium metabisulfite, and sodium bisulfite.

(g) Redox initiators include combinations of reducing agents such as sodium metabisulfite and sodium bisulfite listed as persulfates above; systems based on organic peroxides and tertiary amines, such as benzoyl peroxide; and systems based on organic hydroperoxides and transition metals, such as systems based on cumene hydroperoxide and cobalt naphthate.

Among these, photoradical polymerization initiators are preferred in terms of good curability and storage stability, and specific examples include benzophenone, 4,4'-bis(diethylamino)benzophenone, and 2,2-dimethoxy- 1,2-diphenylethan-1-one, 1-hydroxy-cyclohexyl-phenylketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 2-methyl-1-[4-(methylthio) phenyl]-2-morpholinopropan-1-one, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, 2 , 4,6-trimethylbenzoyl-diphenyl-phosphine oxide is particularly preferred.

In addition, when light irradiation is difficult or heat curing is preferable, azo initiators or peroxides are preferable, and specifically, 2,2'-azobis(methylisobutyrate), t-butyl peroxypivalate, di(4-t-butylcyclohexyl)peroxydicarbonate, t-butylperoxyisopropyl monocarbonate, dicumyl peroxide, benzoyl peroxide, and mixtures thereof.

Component (C) may be used alone or in combination of two or more. Furthermore, one or more of the components (C) may be used in combination with other compounds. When component (C) and other compounds are used in combination, suitable examples of the other compounds include amines such as diethanolmethylamine, dimethylethanolamine, and triethanolamine. Component (C), the above-mentioned amine, and further an iodonium salt such as phenyl iodonium chloride may be used in combination. Further, component (C), the above-mentioned amine, and a dye such as methylene blue may be used in combination.

When using component (C), a polymerization inhibitor can also be added if necessary. The coexistence of component (C) and a polymerization inhibitor in the present curable composition provides the advantage of preventing unintended curing of the curable composition and making it easier to handle. Examples of the polymerization inhibitor include hydroquinone, hydroquinone monomethyl ether, benzoquinone, and p-tert-butylcatechol.

The blending amount of component (C) is preferably 0.01 to 20 parts by weight, more preferably 0.05 to 20 parts by weight, and 0.1 to 100 parts by weight of component (A). The amount is more preferably 20 parts by weight, even more preferably 0.1 to 10 parts by weight, and particularly preferably 0.1 to 5 parts by weight. When the content of component (C) is 0.01 part by weight or more based on 100 parts by weight of component (A), the effect of component (C) is exhibited and good curability is obtained. In addition, since the content of component (C) is 20 parts by weight or less per 100 parts by weight of component (A), it has the advantage that problems such as unintended heat generation, side reactions, and foaming can be avoided during curing. .

[2-4. Other ingredients]
The present curable composition may contain other components as necessary within a range that does not impair the effects of the present invention. Other components include additives (for example, fillers, plasticizers, storage stabilizers, antioxidants, ultraviolet absorbers, flame retardants, antistatic agents, and pigments), and elastomers that adjust the physical properties of the rubber of the cured product. (for example, styrenic block copolymers, etc.), thiol compounds, tertiary amine compounds, and adhesion imparting agents.

(Additive)
The content of the filler and plasticizer in the present curable composition is not particularly limited, but from the viewpoint of the balance between the effect obtained by addition and economical efficiency, the content of the filler and plasticizer is 0.000 parts per 100 parts by weight of component (A). It is preferably 1 to 500 parts by weight, more preferably 1.0 to 300 parts by weight.

The contents of storage stabilizers, antioxidants, ultraviolet absorbers, flame retardants, antistatic agents, and pigments in this curable composition are not particularly limited, but are determined based on the balance between the effects obtained by adding them and economic efficiency. From this point of view, the amount is preferably 0.01 to 20 parts by weight, more preferably 0.01 to 10 parts by weight, based on 100 parts by weight of component (A).

Examples of these additives include various additives described in International Publication No. 2013/047314, JP 2013-216782, and the like.

(Styrenic block copolymer)
Styrene block copolymers include styrene-butadiene copolymer (SBS), styrene-isoprene copolymer (SIS), styrene-ethylene-butylene-styrene copolymer (SEBS), and styrene-ethylene-propylene-styrene. Examples include copolymer (SEPS), styrene-isobutylene-styrene copolymer (SIBS), acrylonitrile-styrene copolymer (AS), and styrene-butadiene-acrylonitrile copolymer (ABS). These styrenic block copolymers may be used alone or in combination of two or more.

Among these, styrene-butadiene copolymer (SBS) and styrene-isoprene copolymer (SIS) have excellent compatibility with other components of the curable composition and provide preferable rubber physical properties. , styrene-ethylene-butylene-styrene copolymer (SEBS), styrene-ethylene-propylene-styrene copolymer (SEPS), and styrene-isobutylene-styrene copolymer (SIBS).

The number average molecular weight of the styrenic block copolymer is not particularly limited, but (i) the viscosity of the present curable composition is within a suitable range, and/or (ii) other than the present curable composition. From the viewpoint of excellent compatibility with the component, the molecular weight is preferably 10,000 to 500,000, more preferably 50,000 to 300,000.

The content of the styrenic block copolymer in the present curable composition is not particularly limited, but from the viewpoint of the balance between tackiness and durability, the content of the styrenic block copolymer is from 0.1 to 100 parts by weight of component (A). It is preferably 1000 parts by weight, more preferably 1.0 to 300 parts by weight.

(thiol compound)
By including a thiol-based compound as another component, the present curable composition can (a) increase crosslinking points, improve curability, and provide a cured product with high hardness and strength. or (b) has the advantage that a cured product with excellent flexibility and adhesiveness can be provided by reducing the number of crosslinking points by chain transfer action.

Examples of thiol compounds include decanethiol, trimethylolpropane tris (3-mercaptopropionate), pentaerythritol tetrakis (3-mercaptopropionate), trimethylolpropane tris (3-mercaptobutyrate), and trimethylolethane tris. (3-mercaptobutyrate), trimethylolethane tris (3-mercaptobutyrate), ethylene glycol bis(3-mercaptoglycolate), butanediol bis(3-mercaptoglycolate), trimethylolpropane tris(3-mercaptoglycolate), glycolate), pentaerythritol tetrakis (3-mercaptoglycolate), tris-[(3-mercaptopropionyloxy)-ethyl]-isocyanurate, pentaerythritol tetrakis (3-mercaptopropionate), tetraethylene glycol bis(3 -mercaptopropionate), dipentaerythritol hexakis (3-mercaptopropionate), pentaerythritol tetrakis (3-mercaptobutyrate), 1,4-bis(3-mercaptobutyryloxy)butane, 1,3, Examples include 5-tris(3-mercabutyloxyethyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione. These thiol compounds may be used alone or in combination of two or more.

The content of the thiol-based compound in the present curable composition is not particularly limited, but since the present curable composition has excellent curability and ease of handling, the content of the thiol compound is 0.0000% based on 100 parts by weight of component (A). It is preferably 1 to 100 parts by weight, more preferably 0.5 to 30 parts by weight.

(Tertiary amine compound)
This curable composition has the advantage that photocurability can be improved by including a tertiary amine compound as another component.

Examples of tertiary amine compounds include trimethylamine, triethylamine, tributylamine, N,N'-diethanolamine, N,N'-dimethyl-P-toluidine, N,N'-dimethyl-aniline, N-methyl-diethanolamine, N-methyl -dimethanolamine, N,N'-dimethylamino-acetophenone, N,N'-dimethylaminobenzophenone, N,N'-diethylamino-benzophenone, triisopropanolamine and the like. These tertiary amine compounds may be used alone or in combination of two or more.

The content of the tertiary amine compound in the present curable composition is not particularly limited, but since the present curable composition has excellent curability, the content of the tertiary amine compound is 0.1 to 100 parts by weight based on 100 parts by weight of component (A). It is preferably 0.5 to 30 parts by weight, more preferably 0.5 to 30 parts by weight.

(Adhesive agent)
This curable composition has the advantage that the tackiness of the cured product can be improved by including an adhesion imparting agent (also referred to as an "adhesion imparting agent") as another component.

As the adhesion agent, 3-(meth)acryloxypropylmethyldimethoxysilane, 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropylmethyldiethoxysilane, 3-(meth)acrylic Oxypropyltriethoxysilane, (meth)acryloxyoctyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltrichlorosilane, 3-glycidyloxypropylmethyldimethoxysilane, 3-glycidyloxypropyltrimethoxysilane, 3- Glycidyloxypropylmethyldiethoxysilane, 3-glycidyloxypropyltriethoxysilane, vinyltris(2-methoxyethoxy)silane, 3-chloropropyltrimethoxysilane, 3-aminopropylmethyldimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-aminopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropylmethyldiethoxysilane, 3-mercaptopropyltriethoxysilane, 3-(2-aminoethylamino)propylmethyldimethoxysilane, 3-(2-aminoethylamino)propyltrimethoxysilane, 3-(2-aminoethylamino)propylmethyldiethoxysilane, 3-(2-aminoethyl Amino)propyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-ureidopropyltriethoxysilane, 2-hydroxyethyl (meth)acrylate phosphate, methacryloxyoxyethyl acid phosphate monoethylamine Examples include half salt, 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. These adhesion imparting agents may be used alone or in combination of two or more.

Among these, 3-(meth)acryloxypropylmethyldimethoxysilane, 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropylmethyldiethoxysilane, and 3-(meth)acryloxypropylmethyldiethoxysilane are used because of their excellent adhesive properties. (meth)acryloxypropyltriethoxysilane, 3-glycidyloxypropylmethyldimethoxysilane, 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropylmethyldiethoxysilane, 3-glycidyloxypropyltriethoxysilane, 3-amino Propylmethyldimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-aminopropyltriethoxysilane, 3-(2-aminoethylamino)propylmethyldimethoxysilane, 3-(2-amino ethylamino)propyltrimethoxysilane, 3-(2-aminoethylamino)propylmethyldiethoxysilane, 3-(2-aminoethylamino)propyltriethoxysilane, 2-hydroxyethyl (meth)acrylate phosphate, 2 Particularly preferred are -hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate.

The content of the adhesion-imparting agent in the present curable composition is not particularly limited, but from the viewpoint of the balance between curability and adhesiveness, the content of the adhesion-imparting agent is 0.01 to 20 parts by weight per 100 parts by weight of component (A). parts by weight, and more preferably 0.1 to 10 parts by weight.

[3. Self-healing material]
The self-healing material according to one embodiment of the present invention includes [2. Curable composition] and has self-healing properties. In this specification, "having self-healing properties" means (i) when abrasion and/or scratches occur on the cured product obtained by curing the self-healing material, the cured product is heated to a certain level. When left standing for a period of time, the width and/or length of the scratch becomes smaller than before heating, or (ii) the cut surface of each cured product obtained by cutting the cured product obtained by curing the self-healing material. This means that if they are placed facing each other, then heated and left to stand for a certain period of time, the cut portions will adhere and the cured product will be integrated.

Here, the heating operation is not necessarily necessary; for example, self-repair may be performed at room temperature. It is preferable to heat the cured product from the viewpoint of improving self-repairing ability. The heating operation is preferably performed at 200°C or lower, more preferably 100°C or lower. In addition to heating, light irradiation, pressurization, and the like can be cited as operations for increasing self-repairing ability. In addition to the heating operation, light irradiation, pressurization, etc. may be performed, and when two or more types of operations are performed, these operations may be performed simultaneously or sequentially. When performing the operations in sequence, the order of the operations is not particularly limited.

Creating scratches and/or scratches on the cured product as described above, or cutting the cured product, heating the cured product with the scratches and/or scratches, or each cured product resulting from cutting, Light irradiation and/or pressurization will hereinafter also be referred to as "operation related to self-repair." Moreover, the cured material subjected to the operation related to self-repair is also referred to as a "test piece" below.

Self-healing properties in this specification can be confirmed by observing changes in appearance, such as resolution of defects caused to the material such as scratches, scratches, and cuts. Further, the self-healing property can also be quantitatively evaluated by measuring the mechanical properties of the test piece before and after the operation related to self-healing and comparing the mechanical properties before and after the operation. When comparing specific mechanical properties before and after the self-repairing operation, it is preferable that the mechanical properties after the operation have recovered to 50% or more of the mechanical properties before the operation, preferably 80% or more. is more preferable, and it is even more preferable that the recovery rate is 98% or more.

[4. Cured product]
The cured product according to one embodiment of the present invention includes [2. Curable composition], or the curable composition described in [3. It is made by curing the self-healing material described in the section ``Self-healing material''. Since the cured product exhibits self-healing properties when heated as described above, it can be said to be a so-called "vitrimer".

(Curing method)
The cured product according to one embodiment of the present invention is obtained by applying active energy rays and/or heat as an external stimulus to the curable composition and curing it.

When component (C) is a photoradical polymerization initiator, the external stimulus is irradiation with light (active energy rays). Light sources for active energy rays include low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, black light lamps, microwave-excited mercury lamps, metal halide lamps, sodium lamps, halogen lamps, xenon lamps, LEDs, fluorescent lamps, and sunlight. , an electron beam irradiation device, a UV irradiation device, a laser, etc.

The irradiation amount of active energy rays is preferably an integrated light amount of 1 kJ/m ² or more, more preferably 10 kJ/m ² or more. If the cumulative amount of light is 1 kJ/m ² or more, the curable composition can be sufficiently cured.

Efficient curing can be achieved by matching the wavelength of active energy rays emitted from the light source and the absorption wavelength (and/or maximum absorption wavelength) of component (C) as much as possible.

When component (C) is a thermal radical polymerization initiator, the external stimulus is heat (heating). The heating temperature and heating time are not particularly limited and vary depending on the type of thermal radical polymerization initiator used, but are usually preferably 50 to 250°C, more preferably 70 to 200°C. The heating time (curing time) varies depending on the type of thermal radical polymerization initiator used, additives, heating temperature (reaction temperature), etc., but is usually in the range of 1 minute to 5 hours.

Curing of the present curable composition can be performed under various atmospheres such as air, nitrogen, and argon. It is preferable to cure the present curable composition in the atmosphere because it can be easily carried out without requiring special equipment. Furthermore, if there is a concern that curing may be inhibited by oxygen in the atmosphere, it is preferable to cure under an inert gas such as nitrogen or argon.

[5. Use]
The curable composition according to an embodiment of the present invention is, for example, a self-healing material, a sealing material, a coating material, a surface coating agent, an adhesive additive, a paint, an adhesive, a pressure-sensitive adhesive, a gasket material, a coating material, Resist materials, vibration isolating materials, damping materials, shock absorbing materials, cushioning materials, electrical insulation materials, foams, inks, casting agents, potting agents, molding materials, underfill materials, die bonding materials, fillers, optical materials, It can be used in various forms such as electrical/electronic parts, medical equipment/medical parts, battery materials, automobile parts, ship parts, aircraft parts, architectural parts, and audio parts. In addition, this cured product applied to these applications can be used in various forms such as sheet (film), tape, and molded bodies (packing, O-rings, belts, tubes, valves, hoses, etc.). is preferred.

[6. summary〕
The present invention includes the following aspects.
<1>
(A) monofunctional vinyl monomer,
(B) a polyfunctional vinyl monomer having two or more vinyl groups and a boronic acid ester group or a boric acid ester group in one molecule, and
(C) A curable composition containing a polymerization initiator.
<2>
The curable composition according to <1>, wherein the component (B) has two vinyl groups in one molecule.
<3>
The curable composition according to <1> or <2>, wherein the component (B) has two or more boron elements in one molecule.
<4>
The curable composition according to any one of <1> to <3>, wherein the component (B) is a compound represented by general formula (1).

(R ¹ is a divalent organic group, R ² to R ⁴ are each independently hydrogen or a monovalent hydrocarbon group, R ⁵ is a divalent organic group, R ⁶ to R ⁸ are each independently hydrogen or (Represents a methyl group.)
<5>
A self-healing material comprising the curable composition according to any one of <1> to <4>.
<6>
A cured product obtained by curing the curable composition according to any one of <1> to <4>.

The present invention will be explained in detail based on Examples, but the present invention is not limited thereto.

〔Evaluation methods〕
Measurements and evaluations in Examples and Comparative Examples were performed by the following methods.

<Tensile properties>
The curable composition was applied onto a PET film to a thickness of 0.5 mm. Thereafter, the curable composition is cured by irradiating UV light (irradiation conditions: illuminance 500 mW/cm2, light amount 3000 mJ/cm2) using a UV irradiation device (manufactured by Fusion UV Systems Japan Co., Ltd., model: LH6). A sheet-like cured product was obtained. A No. 7 dumbbell-shaped test piece was prepared from the obtained cured product.

Using the obtained test piece, a tensile test was conducted at room temperature (23° C.) at a tensile speed of 200 mm/min in accordance with JIS K 6251:2017, and the 30% modulus (M30) was measured. The 30% modulus (M30) is the tensile strength (MPa) when the test piece is stretched 30%.

<Self-repairability>
The dumbbell-shaped test piece obtained as described above was cut in the center with a cutter. Thereafter, the cut surfaces were joined and the test piece was fixed using adhesive tape so that the cut surfaces would not separate. Next, the test pieces were allowed to stand for 3 days in an oven at 80° C. After being left still, it was confirmed whether the joints of the test pieces were integrated.

If they were not integrated, the self-repairing property was "absent", and if they were integrated, the self-repairing property was "yes". In addition, in order to quantitatively evaluate the self-healing property, the tensile properties were measured before and after the self-healing property test, and the tensile properties of the two were compared.

[Synthesis Example 1] Synthesis of 2,3-dihydroxypropyl acrylate Acrylic acid 36g (0.50mol), 4-methoxyphenol (MEHQ) 0.64g (0.0052mol), tetramethylammonium chloride (TMAC) 0.45g ( 0.0041 mol) were mixed, heated to 90°C, and stirred. Then, while stirring, 37 g (0.50 mol) of glycidol was added dropwise over 3 hours. After that, stirring was continued at 90°C for 9 hours, and then the temperature was returned to room temperature. The resulting reaction mixture was purified by column chromatography (silica gel, solvent: acetone) to obtain 44 g (yield: 60%) of 2,3-dihydroxypropyl acrylate as a colorless transparent liquid.

The results of ¹ H-NMR of the obtained compound were as follows. ¹ H-NMR (400 MHz, CDCl ₃ ): δ=2.8-3.0 (bs, 2H), 3.5-4.1 (m, 3H), 4.3 (d, 2H), 5. 9 (d, 1H), 6.2 (dd, 1H), 6.5 (d, 1H).

[Synthesis Example 2] Synthesis of 2,2'-(1,4-phenylene)-bis[4-(acryloyloxymethyl)-1,3,2-dioxaborolane] 10 g (0.068 mol) of 2,3-dihydroxypropyl acrylate ), 5.7 g (0.034 mol) of 1,4-phenylene diboronic acid, 60 ml of tetrahydrofuran (THF), and 10 g of magnesium sulfate (MgSO ₄ ) were mixed at room temperature and stirred for 24 hours to react. After the reaction, the resulting reaction mixture was filtered to obtain a reaction solution. Next, the obtained reaction solution was distilled off under reduced pressure to obtain a viscous pale yellow transparent liquid of 2,2'-(1,4-phenylene)-bis[4-(acryloyloxymethyl)-1,3 , 2-dioxaborolane] was obtained (13 g (yield: 83%)).

The results of ¹ H-NMR of the obtained compound were as follows. ¹ H-NMR (400 MHz, CDCl ₃ ): δ = 3.8 (m, 2H), 4.1-4.5 (m, 8H), 5.9 (d, 2H), 6.1 (dd, 2H), 6.4 (d, 2H), 7.8 (s, 4H).

Note that the compound obtained in Synthesis Example 2 is also referred to below as a "boronic acid ester group-containing polyfunctional acrylate."

[Synthesis Example 3] Synthesis of 2,2'-(1,4-phenylene)-bis[4-(methacryloyloxymethyl)-1,3,2-dioxaborolane] 2,3-dihydroxypropyl methacrylate 0.552 g (0 0.00345 mol), 0.285 g (0.00172 mol) of 1,4-phenylene diboronic acid, 7 ml of tetrahydrofuran (THF), and 0.860 g of magnesium sulfate (MgSO ₄ ) were mixed at room temperature and stirred for 24 hours to react. . After the reaction, the resulting reaction mixture was filtered to obtain a reaction solution. The resulting reaction solution was then distilled off under reduced pressure to obtain 2,2'-(1,4-phenylene)-bis[4-(methacryloyloxymethyl)-1,3,2-dioxaborolane], a colorless transparent liquid. ] 0.544g (yield 65%) was obtained.

The results of ¹ H-NMR of the obtained compound were as follows. ¹ H-NMR (400 MHz, CDCl ₃ ): δ = 3.8 (m, 2H), 4.2-4.5 (m, 8H), 5.6 (s, 2H), 6.1 (s, 2H), 7.8 (s, 4H).

Note that the compound obtained in Synthesis Example 3 is also referred to below as "boronic acid ester group-containing polyfunctional methacrylate."

[Materials used in Examples and Comparative Examples]
The materials used in the following Examples and Comparative Examples are as follows.
<(A) component>
・Isononyl acrylate (manufactured by Tokyo Chemical Industry Co., Ltd.)
<(B) component>
- Boronic acid ester group-containing polyfunctional acrylate synthesized in Synthesis Example 2 <Comparative component of component (B)>
・1,9-nonanediol diacrylate (manufactured by Kyoeisha Chemical Co., Ltd., light acrylate 1,9ND-A)
<(C) component>
・2-Hydroxy-2-methyl-1-phenyl-propan-1-one (manufactured by Ciba Specialty Chemicals, trade name: Darocure 1173)
・Bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (manufactured by BASF Japan, product name: Irgacure 819)
・1-Hydroxycyclohexyl phenyl ketone (manufactured by IGM Resins, product name: Omnirad184)
<Other ingredients>
・Antioxidant: Adekastab AO-50 (manufactured by Adeka Co., Ltd.)
[Example 1]
By mixing isononyl acrylate, the polyfunctional acrylate containing a boronic acid ester group obtained in Synthesis Example 2, Darocure 1173, Irgacure 819, and Adekastab AO-50 in the weight ratio shown in Table 1 below, and mixing until uniform. A pale yellow transparent curable composition was obtained. The obtained curable composition was irradiated with UV light to obtain a cured product according to the methods described in <Tensile properties> and <Self-healing properties> above, and the tensile properties of the obtained cured product were measured and Self-repairability was evaluated.

As explained above, the dumbbell-shaped test piece according to Example 1 was cut at the center, the cut surfaces produced by cutting were overlapped, and the test piece was left to stand at 80°C for 3 days. , and self-healing properties were observed. In addition, when the self-healing property was quantitatively evaluated, the 30% modulus before the self-healing property test (before cutting) was 0.077 MPa, and after the self-healing property test (after cutting and standing at 80°C for 3 days), the 30% modulus was 0.077 MPa. ) had a 30% modulus of 0.090 MPa. From this result, the test piece showed the same level of modulus before and after the self-healing property test, and it was also quantitatively confirmed that it had self-healing property. Furthermore, in the tensile test, the test piece broke at a site other than the pre-cut site, which also confirmed self-healing properties.

[Example 2]
A curable composition and a cured product were obtained using the same formulation as in Example 1, except that the amount of the polyfunctional acrylate containing a boronic acid ester group obtained in Synthesis Example 2 was changed to 10 parts by weight. The tensile properties of the cured product were measured and the self-healing property was evaluated.

As explained above, the dumbbell-shaped test piece according to Example 2 was cut at the center, the cut surfaces produced by the cutting were overlapped, and the test piece was left to stand at 80°C for 3 days. , and self-healing properties were observed. In addition, when the self-healing property was quantitatively evaluated, the 30% modulus before the self-healing property test (before cutting) was 0.15 MPa, and after the self-healing property test (after cutting and standing at 80°C for 3 days), the 30% modulus was 0.15 MPa. ) had a 30% modulus of 0.20 MPa. From this result, the test piece showed the same level of modulus before and after the self-healing property test, and it was also quantitatively confirmed that it had self-healing property. Furthermore, in the tensile test, the test piece broke at a site other than the pre-cut site, which also confirmed self-healing properties.

[Example 3]
A curable composition was prepared using the same formulation as in Example 2, except that 10 parts by weight of the polyfunctional methacrylate containing boronic acid ester groups obtained in Synthesis Example 3 and 0.5 parts by weight of Omnirad 184 as component (C) were used. A cured product and a cured product were obtained, and the self-healing properties of the obtained cured product were evaluated.

As explained above, the dumbbell-shaped test piece according to Example 3 was cut at the center, the cut surfaces produced by the cutting were overlapped, and the test piece was left to stand at 80°C for 3 days. , and self-healing properties were observed.

[Comparative example 1]
A curable composition was obtained using the same formulation as in Example 1, except that component (B) was not added. When the obtained curable composition was irradiated with UV light, it did not harden and a cured product could not be obtained.

[Comparative example 2]
A curable composition and a cured product were obtained using the same formulation as in Example 1, except that light acrylate 1,9ND-A was added as a comparative component of component (B), and self-healing properties of the obtained cured product was evaluated.

As explained above, the dumbbell-shaped test piece according to Comparative Example 2 was cut at the center, the cut surfaces produced by cutting were overlapped, and the test piece was left to stand at 80°C for 3 days. No self-healing property was observed.

[Comparative example 3]
A curable composition and a cured product were obtained using the same formulation as in Comparative Example 2, except that the amount of light acrylate 1,9ND-A added was changed to 10 parts by weight, and evaluation of self-healing properties of the obtained cured product. I did it.

As explained above, when the dumbbell-shaped test piece according to Comparative Example 3 was cut at the center and left to stand at 80°C for 3 days, the test piece was not integrated and no self-healing property was observed. Ta.

A summary of each example and comparative example is shown in Table 1. In Table 1, the amount of each component is shown in parts by weight based on 100 parts by weight of component (A).

The difference between the curable compositions according to Examples 1 to 3 and the curable composition according to Comparative Example 1 is whether or not component (B) was added. As mentioned above, it was confirmed that the obtained cured products of the curable compositions according to Examples 1 to 3 had self-healing properties. On the other hand, when the curable composition according to Comparative Example 1 was irradiated with UV light, it became clear that it did not cure and a cured product could not be obtained.

Also, the difference between Example 1 and Comparative Example 2 and the difference between Example 2 and Comparative Example 3 are whether the (B) component was added or the comparative component of the (B) component was added. . From the comparison between Example 1 and Comparative Example 2 and the comparison between Example 2 and Comparative Example 3, it was confirmed that the resulting cured product had self-healing properties due to the inclusion of component (B).

That is, it was confirmed that by using the curable composition according to one embodiment of the present invention, a curable material having self-healing properties could be obtained.

One embodiment of the present invention can be utilized in the field of curable compositions.

Claims (6)

(A) monofunctional vinyl monomer,
(B) a polyfunctional vinyl monomer having two or more vinyl groups and a boronic acid ester group or a boric acid ester group in one molecule, and
(C) A curable composition containing a polymerization initiator. The curable composition according to claim 1, wherein the component (B) has two vinyl groups in one molecule. The curable composition according to claim 1 or 2, wherein the component (B) has two or more boron elements in one molecule. The curable composition according to any one of claims 1 to 3, wherein the component (B) is a compound represented by general formula (1).
(R ¹ is a divalent organic group, R ² to R ⁴ are each independently hydrogen or a monovalent hydrocarbon group, R ⁵ is a divalent organic group, R ⁶ to R ⁸ are each independently hydrogen or (Represents a methyl group.) A self-healing material comprising a curable composition according to any one of claims 1 to 4. A cured product obtained by curing the curable composition according to any one of claims 1 to 4.