JP2023066720A - Self-repairing material - Google Patents

Abstract

To provide a self-repairing material which is hardly distorted when cutting.SOLUTION: A self-repairing material is composed of a gel containing a cross-linked structure and an aqueous medium, wherein the cross-linked structure consists of a linear polymer having mutually reversibly bondable side groups cross-linked by reversible bonding between the side groups and a structure originating from a cross-linking agent, the cross-linking agent has two or more polymerizable functional groups capable of forming a main chain of the linear polymer in one molecule together with a polymerizable functional group of a monomer forming the linear polymer, and the two or more polymerizable functional groups of the cross-linking agent includes two or more kinds of polymerizable functional groups with mutually different structures.SELECTED DRAWING: None

Description

The present invention relates to self-healing materials.

In recent years, materials with self-healing properties have been extensively studied. As such a material, a polymer gel obtained by cross-linking a linear polymer with a reversible bond is known (for example, Patent Document 1). Reversible bonds include intermolecular interactions such as host-guest interactions, hydrophobic interactions, hydrogen bonds, ionic bonds, coordinate bonds, and π-electron interactions.

WO2013/162019

However, since the polymer gel described above is soft and tacky, it easily adheres to a knife when cutting the polymer gel and is deformed. Hard to reproduce.
The present invention provides a self-healing material that resists deformation when cut.

The present invention has the following aspects.
[1] A self-healing material composed of a gel containing a crosslinked structure and an aqueous medium,
The crosslinked structure is obtained by cross-linking a linear polymer having side groups that can reversibly bond to each other through reversible bonds between the side groups and a structure based on a cross-linking agent,
The cross-linking agent has, in one molecule, two or more polymerizable functional groups capable of forming the main chain of the linear polymer together with the polymerizable functional groups of the monomers forming the linear polymer. ,
The self-repairing material, wherein the two or more polymerizable functional groups of the cross-linking agent include two or more types of polymerizable functional groups having different structures.
[2] The self-repairing material according to [1], wherein the proportion of the cross-linking agent to the total weight of the linear polymer and the aqueous medium is 0.01 to 10% by weight.
[3] The self-repairing material of [1] or [2], which has a hardness of 110% or more of the hardness of a gel having the same composition except that it does not contain a structure based on the cross-linking agent.
[4] The self-healing material according to any one of [1] to [3], which has an adhesive force of 90% or less that of a gel having the same composition except that it does not contain a structure based on the cross-linking agent.
[5] The self-healing ability of any one of [1] to [4], which is 60% or more of the self-healing ability of a gel having the same composition except that it does not contain a structure based on the cross-linking agent. material.

ADVANTAGE OF THE INVENTION According to this invention, the self-healing material which is hard to deform|transform at the time of cutting can be provided.

The meanings and definitions of the terms used in the present invention are as follows.
“Hardness” means durometer hardness measured at 25° C. and 50% RH using a type E durometer according to JIS K 6253-3:2012.
"Adhesion force" is measured by placing a self-repairing material on the surface of a support at 25 ° C., bringing another support into surface contact from a mutually separated state, then retreating and separating, and starting to retreat. It means the maximum stress value (N) applied to the contact point until it completely separates. Specifically, at 25 ° C., a sample of 20 mm length × 20 mm width × 3 mm thickness was cut out from the self-repairing material and placed on the surface of the support, and another support with a diameter of 5 mm was placed on the surface of the sample. The tip surface of a cylindrical polyacetal resin (Delrin (registered trademark) manufactured by DuPont) probe was brought into contact, a load of 100 g was applied, held for 10 seconds, and then released at a speed of 0.5 mm / sec. It is measured using a texture analyzer (for example, texture analyzer TA.XTplus manufactured by Stable Micro Systems), and the maximum stress value (N) is taken as the adhesion force.
"Self-healing ability" is obtained by cutting out two samples of length 60 mm x width 10 mm x thickness 3 mm from the self-healing material, and measuring the breaking elongation A (%) at 25 ° C. in the length direction for one sample. Then, the other sample was cut perpendicular to the length direction at the center of the length direction and divided into two, and then the cut surfaces were brought into contact with each other at 25 ° C. for 5 hours to rebond. The breaking elongation B (%) at 25° C. in the length direction is measured for the sample after (after self-healing), and means the breaking elongation retention rate calculated by the following formula.
Breaking elongation retention rate (%) = B/A x 100
"Breaking elongation" is determined by a tensile test at 25°C and a tensile speed of 100 mm/min. The details are as described in Examples described later.
"~" indicating a numerical range means that the numerical values before and after it are included as lower and upper limits.

A self-repairing material according to one aspect of the present invention is composed of a gel containing a crosslinked structure and an aqueous medium. The crosslinked structure is obtained by cross-linking a linear polymer having side groups that can reversibly bond to each other through reversible bonds between the side groups and a structure based on a cross-linking agent.
The linear polymer, cross-linking agent, and aqueous medium will be described later in detail.

In the self-healing material, the ratio of the cross-linking agent to the total mass of the linear polymer and the aqueous medium is preferably 0.01 to 10% by mass, more preferably 0.05 to 7% by mass, and 0.1 to 5% by mass is more preferred. When the proportion of the cross-linking agent is at least the above lower limit, the hardness of the self-repairing material is higher, the tackiness is lower, and the effect of suppressing deformation during cutting is more excellent. If the ratio of the cross-linking agent is equal to or less than the above upper limit, the self-healing ability will be more excellent.

The ratio of the linear polymer to the total mass of the linear polymer and the aqueous medium is preferably 10-70% by mass, more preferably 20-60% by mass, and even more preferably 30-50% by mass. If the proportion of the linear polymer is at least the above lower limit, the hardness of the self-healing material will be higher, the tackiness will be lower, and the effect of suppressing deformation during cutting will be more excellent. better self-healing ability.

The hardness of the self-healing material is preferably 110% or more, more preferably 115% or more, further preferably 120% or more, relative to the hardness of a gel having the same composition except that it does not contain a structure based on a cross-linking agent. , is preferably 200% or less, more preferably 190% or less, even more preferably 180% or less. If the hardness of the self-repairing material is at least the lower limit, the effect of suppressing deformation during cutting will be more excellent, and if it is at most the upper limit, the self-repairing ability will be more excellent.

The hardness of the self-healing material (durometer hardness measured using a type E durometer, actual value) is preferably 30-90, more preferably 40-85, even more preferably 51-80. If the hardness of the self-repairing material is at least the lower limit, the effect of suppressing deformation during cutting will be more excellent, and if it is at most the upper limit, the self-repairing ability will be more excellent.
The hardness of the self-healing material is determined, for example, by the ratio of the cross-linking agent to the total mass of the linear polymer and the aqueous medium, the type of the cross-linking agent (for example, the number and type of polymerizable functional groups), the linear polymer It can be adjusted by adjusting the ratio of the linear polymer to the total mass of the aqueous medium and the monomer species of the linear polymer.

A "gel of the same composition but without a structure based on a cross-linking agent" is produced in the same manner as the self-healing material, except that no cross-linking agent is used in the production of the self-healing material. This gel contains a crosslinked structure in which the same linear polymer used in the self-healing material is crosslinked only by reversible bonds between side groups, and an aqueous medium. The ratio of the linear polymer to the total mass with the aqueous medium is the same as for the self-healing material.

The adhesion of the self-repairing material is preferably 100% or less, more preferably 95% or less, even more preferably 90% or less, relative to the adhesion of a gel having the same composition except that it does not contain a structure based on a cross-linking agent. , is preferably 30% or more, more preferably 40% or more, and even more preferably 50% or more. If the adhesive force of the self-repairing material is equal to or less than the upper limit, the effect of suppressing deformation during cutting will be more excellent, and if it is equal to or more than the lower limit, the self-repairing ability will be more excellent.

The adhesive force (actually measured value) of the self-healing material is preferably 0.1 to 0.8N, more preferably 0.15 to 0.7N, even more preferably 0.2 to 0.6N. If the adhesive force of the self-repairing material is equal to or less than the upper limit, the effect of suppressing deformation during cutting will be more excellent, and if it is equal to or more than the lower limit, the self-repairing ability will be more excellent.
The adhesion of the self-healing material depends on, for example, the ratio of the cross-linking agent to the total mass of the linear polymer and the aqueous medium, the type of the cross-linking agent (for example, the number and type of polymerizable functional groups), the linear polymer It can be adjusted by adjusting the ratio of the linear polymer to the total mass of the aqueous medium and the monomer species of the linear polymer.

The self-repairing ability of the self-repairing material is preferably 40% or more, more preferably 50% or more, and even more preferably 60% or more, relative to the self-repairing ability of a gel having the same composition except that it does not contain a structure based on a cross-linking agent. . The higher the self-repairing ability, the better, and although the upper limit is not particularly limited, it is, for example, 90%. If the self-repairing ability is at least the above lower limit, the usefulness as a self-repairing material is high.

The self-repairing ability (actual value) of the self-repairing material is preferably 10% or more, more preferably 15% or more, and even more preferably 20% or more. The higher the self-repairing ability, the better, and although the upper limit is not particularly limited, it is, for example, 90%. If the self-repairing ability of the self-repairing material is at least the above lower limit, it is highly useful as a self-repairing material.
The self-repairing ability of the self-repairing material is determined by, for example, the ratio of the cross-linking agent to the total mass of the linear polymer and the aqueous medium, the type of the cross-linking agent (for example, the number and type of polymerizable functional groups), the linear polymer It can be adjusted by adjusting the ratio of the linear polymer to the total mass of the coalescence and the aqueous medium and the monomer species of the linear polymer.

(linear polymer)
A linear polymer is a monomeric polymer having one polymerizable functional group. A "monomer" shall mean what has one polymerizable functional group below.

The polymerizable functional group of the monomer forming the linear polymer (hereinafter also referred to as "polymerizable functional group A") becomes the main component of the linear polymer through a polymerization reaction (radical polymerization, anionic polymerization, etc.). form a chain. Examples of the polymerizable functional group A include an acryloyloxy group, a methacryloyloxy group, an acrylamide group, a methacrylamide group, a vinyl group, an allyl group, and an epoxy group.
When two or more types of monomers are used to form the linear polymer, the polymerizable functional groups A possessed by the two or more types of monomers may be different as long as they are capable of undergoing a polymerization reaction with each other.
The polymerizable functional group A is preferably a photopolymerizable functional group, such as an acryloyloxy group, a methacryloyloxy group, an acrylamide group, a methacrylamide group, and a vinyl group, since thermal deformation can be avoided because no heating is required during polymerization. , an allyl group, and an epoxy group.

Linear polymers have side groups that can reversibly bond to each other. Hereinafter, one of the side groups capable of reversibly bonding to each other is also referred to as the first side group, and the other as the second side group. Since the bond between the first side group and the second side group is reversible, the gel exhibits self-healing properties.
Reversible bonds include intermolecular interactions such as host-guest interactions, hydrophobic interactions, hydrogen bonds, ionic bonds, coordinate bonds, and π-electron interactions. The bond between the first side group and the second side group may be one of these, or a combination of two or more.
Examples of combinations of first side groups and second side groups include combinations of host groups and guest groups, combinations of hydrophobic substituents in polar media, combinations of hydrogen bond donating groups and hydrogen bond accepting groups. combination, a combination of a cationic group and an anionic group, a combination of an electron-donating group and an electron-accepting group in a coordinate bond, a combination of substituents having π electrons, and the like.

As a combination of the first side group and the second side group, a combination of a host group and a guest group is preferable from the viewpoint of the magnitude of intermolecular interaction. The host group and guest group form a reversible bond through host-guest interaction. The host group and guest group may be contained in one linear polymer or may be contained in different linear polymers.

Examples of the host group include known host groups such as cyclodextrin, calixarene, crown ether, cyclophane, and cucurbituril derivatives. Specific examples of host groups include α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, calix[6]arenesulfonic acid, calix[8]arenesulfonic acid, 12-crown-4, 18-crown-6. , [6]paracyclophane, [2,2]paracyclophane, cucurbit[6]uril, and cucurbit[8]uril. The host groups exemplified above may be used singly or in combination of two or more. Preferred host groups are α-cyclodextrin, β-cyclodextrin, or γ-cyclodextrin.

The guest group may be any group that can serve as a guest group for the corresponding host group, and can be appropriately selected according to the host group. Specific examples of the guest group include an optionally substituted alkyl group, an optionally substituted cycloalkyl group, an optionally substituted aralkyl group, and an optionally substituted alkyl group. aryl groups that may be substituted.

A linear polymer typically comprises a unit based on a monomer having a first side group (hereinafter also referred to as "monomer (1)") and a unit having a second side group. and a unit based on a monomer (hereinafter also referred to as "monomer (2)"). The linear polymer may further contain units based on a monomer having no first side group and no second side group (hereinafter also referred to as "monomer (3)"). .

Any monomer (1) may be used as long as it has a polymerizable functional group A and a first side group. The monomer (1) may have two or more first side groups.
A preferred example of the monomer (1) is a host group-containing monomer represented by the following formula 1.
CH ₂ =C(R ¹ )-C(=O)-QR ² Formula 1
However, R ¹ represents a hydrogen atom or a methyl group, Q represents O or NH, and R ² represents α-cyclodextrin, β-cyclodextrin or γ-cyclodextrin.
The host group-containing monomer can be produced, for example, by the methods described in WO2013/162019 and WO2012/036069.
Monomer (1) may be used singly or in combination of two or more.

Any monomer (2) may be used as long as it has a polymerizable functional group A and a second side group. The guest group-containing monomer may have two or more second side groups.
A preferred example of the monomer (2) is a guest group-containing monomer represented by the following formula 2.
CH ₂ =C(R ³ )-R ⁴ Formula 2
However, R ³ represents a hydrogen atom or a methyl group, R ⁴ represents an optionally substituted aryl group, C(=O)OR ⁵ or C(=O)NHR ⁵ , and R ⁵ represents an optionally substituted alkyl group, an optionally substituted cycloalkyl group, or an optionally substituted aralkyl group.

The aryl group for ^R4 may be monocyclic or polycyclic, and includes, for example, phenyl, toluyl, xylyl, naphthyl, anthryl and phenanthryl groups.
The substituents that the aryl group may have include, for example, an alkyl group (eg, an alkyl group having 1 to 18 carbon atoms), a halogen atom (eg, a fluorine atom, a chlorine atom, a bromine atom), a carboxy group, an ester group, An amide group, an azo group having an aryl group, and a hydroxyl group which may be protected can be mentioned. The number of substituents is, for example, 1-3.

The alkyl group at ^R5 may be linear or branched. The number of carbon atoms in the alkyl group is, for example, 1-18. Specifically, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, isohexyl group, dodecyl group , an octadecyl group.
Examples of substituents that the alkyl group may have include a halogen atom, a carboxy group, an ester group, an amide group, an optionally protected hydroxyl group, and a ferrocene group. The number of substituents is, for example, 1-3.

Cycloalkyl groups in ^R5 may be monocyclic or polycyclic. The cycloalkyl group has, for example, 3 to 18 carbon atoms. Specific examples include a cyclohexyl group and an adamantyl group.
Substituents that the cycloalkyl group may have include, for example, an alkyl group (eg, an alkyl group having 1 to 18 carbon atoms), a halogen atom (eg, a fluorine atom, a chlorine atom, a bromine atom), a carboxy group, and an ester group. , an amide group, an optionally protected hydroxyl group, and a ferrocene group. The number of substituents is, for example, 1-3.

Examples of the aralkyl group for R ⁵ include groups in which an alkyl group having 1 to 3 carbon atoms is substituted with an aryl group. The aryl group includes the same aryl groups as those for ^R4 . Specific examples of aralkyl groups include benzyl, naphthylmethyl, anthracenemethyl, and pyrenemethyl groups.
Examples of substituents that the aralkyl group may have include an alkyl group (eg, an alkyl group having 1 to 18 carbon atoms), a halogen atom (eg, a fluorine atom, a chlorine atom, a bromine atom), a carboxy group, an ester group, An amide group, an azo group having an aryl group, and a hydroxyl group which may be protected can be mentioned. The number of substituents is, for example, 1-3. Examples of substituted aralkyl groups include hydroxyphenylmethyl, methylphenylmethyl, dimethylphenylmethyl, trimethylphenylmethyl, carboxyphenylmethyl, hydroxymethylphenylmethyl and triphenylmethyl groups.

Among the guest group-containing monomers, n-butyl acrylate, t-butyl acrylate, N-(1-adamantyl)acrylamide, N-benzylacrylamide, N-1-naphthylmethylacrylamide, and styrene are preferred.
Two or more kinds of the monomer (2) may be used in combination.

The monomer (3) may be copolymerizable with the monomers (1) and (2), but from the viewpoint of polymerization reactivity, acrylamide, methacrylamide, acrylic acid, and methacrylic acid. preferable.
Two or more of the monomers (3) may be used in combination.

The content of the units based on the monomer (1) is preferably 0.1 to 20 mol% with respect to the total 100 mol% of the units based on all the monomers constituting the linear polymer, and 0.1 to 20 mol%. 3 to 13 mol % is more preferred.
The content of the units based on the monomer (2) is preferably 0.1 to 20 mol%, based on the total 100 mol% of the units based on all the monomers constituting the linear polymer, and 0.1 to 20 mol%. 3 to 13 mol % is more preferred.
The content of units based on the monomer (3) is preferably 60 to 99.8 mol%, preferably 74 to 99.4 mol % is more preferred.

(crosslinking agent)
The cross-linking agent is a polymerizable functional group capable of forming the main chain of the linear polymer together with the polymerizable functional group A of the monomer forming the linear polymer (hereinafter also referred to as "polymerizable functional group B" ) in one molecule. Two or more polymerizable functional groups B include two or more polymerizable functional groups having different structures. As a result, while maintaining sufficient self-repairing ability, the hardness can be increased, the tackiness can be reduced, and deformation during cutting can be prevented.

The polymerizable functional group B may be any one capable of undergoing a polymerization reaction with the polymerizable functional group A. For example, two or more types of polymerizable functional groups having different structures can be appropriately selected from the polymerizable functional groups exemplified as the polymerizable functional group A. . Examples of combinations of two or more polymerizable functional groups having different structures include the following.
(1) a combination of an acryloyloxy group and an allyl group,
(2) a combination of an acryloyloxy group, an allyl group and a vinyl group;
(3) a combination of a methacryloyloxy group and an allyl group;
(4) a combination of a methacryloyloxy group, an allyl group and a vinyl group;
(5) a combination of a vinyl group and an allyl group;
(6) a combination of an acrylamide group and an allyl group;
(7) a combination of a methacrylamide group and an allyl group;
(8) A combination of an epoxy group and an allyl group.
Among these, the combination of any of (1), (3), (6), and (7) is preferable from the viewpoint of achieving both the effect of suppressing deformation during cutting and the self-healing ability, and (1), (6) is more preferred.
In combination (1), the number of acryloyloxy groups and allyl groups in one molecule of the cross-linking agent may be 1 or 2 or more. The same applies to other combinations.
The total number of polymerizable functional groups B in one molecule is preferably 2-3.

Specific examples of the cross-linking agent include 3-(triallylsilyl)propyl acrylate (compound represented by Formula 3 below), 1-ethenyl-1-(2-propen-1-yl)-3-butene-1- yl-2-propenoate (compound represented by the following formula 4).
Two or more cross-linking agents may be used in combination.

(aqueous medium)
The aqueous medium includes water and a mixed medium of water and a hydrophilic organic solvent.
A hydrophilic organic solvent is an organic solvent that is miscible with water in any proportion. Examples of hydrophilic organic solvents include N,N-dimethylformamide (DMF), tetrahydrofuran (THF), dimethylsulfoxide (DMSO), ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, glycerin. , diethylene glycol monoethyl ether, ethylene glycol monoethyl ether acetate, ethylene glycol mono-n-butyl ether, and ethylene glycol monomethyl ether. These hydrophilic organic solvents may be used in combination of two or more. Among these, ethylene glycol and propylene glycol are preferable from the viewpoint of suppressing deterioration of self-repairing ability due to aging.
The mass ratio of water to hydrophilic organic solvent in the mixed medium is preferably water:hydrophilic organic solvent=20:100 to 200:100, more preferably 40:100 to 160:100.

(Method for producing self-healing material)
The self-repairing material can be produced by a method of polymerizing a monomer forming a linear polymer and a cross-linking agent in the presence of an aqueous medium.
A polymerization reaction can be carried out by a known method. For example, when the polymerizable functional groups A and B are photopolymerizable, a monomer, a cross-linking agent and a photopolymerization initiator are dissolved or dispersed in an aqueous medium, and the resulting mixture is irradiated with radiation. , the polymerization reaction proceeds and a self-repairing material is obtained. Radiation includes, for example, ultraviolet rays, gamma rays, and electron beams. As for irradiation conditions of radiation, for example, in the case of ultraviolet rays having a wavelength of 365 nm, it is preferable to irradiate so that the integrated amount of light is 3000 mJ/cm ² or more.

The ratio of the cross-linking agent to the total mass of the monomer and the aqueous medium is preferably 0.01-10% by mass, more preferably 0.05-7% by mass, and even more preferably 0.1-5% by mass. When the proportion of the cross-linking agent is at least the above lower limit, the hardness of the self-repairing material is higher, the tackiness is lower, and the effect of suppressing deformation during cutting is more excellent. If the ratio of the cross-linking agent is equal to or less than the above upper limit, the self-healing ability will be more excellent.

The ratio of the monomer to the total mass of the monomer and the aqueous medium is preferably 10-70% by mass, more preferably 20-60% by mass, and even more preferably 30-50% by mass. When the proportion of the monomer is at least the lower limit, the hardness of the self-healing material is higher, the tackiness is lower, and the effect of suppressing deformation during cutting is more excellent. Better self-healing ability.

(Use of self-repairing material)
Self-repairing materials can be used for applications such as molding materials for transferring fine shapes. It is useful as a large mold material because it can be made larger by rebonding multiple self-repairing materials, it is less likely to be deformed by cutting when it has an uneven shape, and it has a certain degree of hardness.

EXAMPLES The present invention will be described in more detail below using examples, but the present invention is not limited to these examples. "Parts" means "mass parts".
Examples 1 to 2 and 9 are examples, and Examples 3 to 8 and 10 are comparative examples.

(Evaluation method)
<Initial tensile strength and elongation at break>
A sample of length 60 mm × width 10 mm × thickness 3 mm was cut out from the self-healing material obtained in each example, and a tensile test was performed at 25 ° C. using "AUTOGRAPH AG-Xplus" manufactured by Shimadzu Corporation, and self-healing was performed. The breaking point of the elastic material was observed. The tensile test was performed by an up method in which the lower end of the sample was fixed and the upper end was operated at a tensile speed of 100 mm/min. In the stroke test force curve obtained in the tensile test, the maximum stress value (kPa) up to the end point from the breaking point to the end point was taken as the tensile strength of the self-healing material. Also, the elongation at break (%) was calculated by the following formula.
Elongation at break (%) = (L-L ₀ )/L ₀ × 100
_L0 indicates the length (mm) of the sample before the tensile test, and L indicates the length (mm) of the sample at break in the tensile test.

<Tensile strength and elongation at break after self-healing>
A 60 mm long by 10 mm wide by 3 mm thick sample was cut from the self-healing material and cut in two at the center of the length perpendicular to the length. The cut surfaces were then brought into contact with each other at 25° C. for 5 hours to rebond. The tensile strength and elongation at break of the sample after recombination (after self-healing) were determined in the same manner as described above.

<Self-healing ability (breaking elongation retention rate)>
The breaking elongation retention rate (%) was calculated by the following formula, and the value was taken as the self-healing ability.
Breaking elongation retention rate (%) = B/A x 100
Here, A indicates the initial breaking elongation (%), and B indicates the breaking elongation (%) after self-healing.

<Hardness>
The hardness of the self-healing material was measured according to JIS K 6253-3:2012 at 25° C.×50% RH using a type E durometer (manufactured by Niigata Seiki Co., Ltd., Asker rubber hardness tester E type).

<Tackiness (adhesion)>
A sample of 20 mm long×20 mm wide×3 mm thick was cut out from the self-healing material obtained in each example, and the adhesive force at 25° C. was measured using the following equipment and probe under the following measurement conditions. Specifically, at 25° C., the sample was placed on the surface of the support, the tip of the probe was brought into contact with the surface of the sample, a load of 100 g was applied, held for 10 seconds, and then separated at a speed of 0.5 mm/second. The change in load was measured, and the maximum stress value (N) was taken as the adhesion force.
[Measuring instrument] "Texture Analyzer TA. XTplus" manufactured by Stable Micro Systems.
[Probe] Cylindrical shape with a diameter of 5 mm, material: polyacetal.
[Measurement Conditions] Test Speed: 0.5 mm/sec, Applied Force: 100 g, Contact Time: 10 sec.

(Raw materials used)
CD-AAm: mono-6-(acrylamide)-β-cyclodextrin, molecular weight 1188, synthetic product prepared according to the examples of WO2012/036069.
AD-AAm: N-(1-adamantyl)acrylamide, molecular weight 204, synthetic product prepared according to the examples of WO2012/036069.
AAm: acrylamide, molecular weight 71, manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.
AA: acrylic acid, molecular weight 100, manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.
Glycerin: manufactured by Fujifilm Wako Pure Chemical Industries.
AIBN: Azobisisobutyronitrile, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.

Cross-linking agent 1: 3-(triallylsilyl)propyl acrylate, manufactured by Tokyo Chemical Industry Co., Ltd.
Crosslinker 2: 1-ethenyl-1-(2-propen-1-yl)-3-buten-1-yl-2-propenoate, Chemieliva Pharmaceutical.
Cross-linking agent 3: N,N-bis(2-acrylamidoethyl)acrylamide, manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.
Cross-linking agent 4: 1,3,5-triacryloylhexahydro-1,3,5-triazine, manufactured by Tokyo Chemical Industry Co., Ltd.
Cross-linking agent 5: Pentaerythritol tetraacrylate, manufactured by Shin-Nakamura Chemical Co., Ltd.
Cross-linking agent 6: Triisopropylsilyl acrylate, manufactured by Shin-Nakamura Chemical Co., Ltd.
Cross-linking agent 7: triallyl(methyl)silane, manufactured by Shin-Nakamura Chemical Co., Ltd.

(Examples 1-8)
CD-AAm, AD-AAm, AAm, pure water and glycerin are placed in a container in the amounts (parts) shown in Table 1, stirred at 60 rpm for 30 minutes with a magnetic stirrer, and then AIBN and the cross-linking agent shown in Table 1 are added. was added in the amounts (parts) shown in Table 1, and the resulting mixture was subjected to a polymerization reaction. In this polymerization reaction, the mixture was placed in a mold with a size of 100×70×3 mm made of a rubber sheet, and a polyethylene terephthalate (PET) film (“Cosmoshine A4300” manufactured by Toyobo Co., Ltd.) was placed over the mixture so as to cover the mold. ) was placed on the PET film, and a high-pressure mercury lamp (“HLR100T-2” manufactured by AS ONE) was used to irradiate the mixture with ultraviolet rays at an irradiation intensity of 1.7 mW/cm ² for 5 minutes. . This polymerization reaction yielded a gel-like self-healing material.
Table 2 shows the number of types of polymerizable functional groups contained in the cross-linking agent used in each example, the initial breaking elongation and tensile strength of the obtained self-healing material, the breaking elongation and tensile strength after self-healing, self-healing strength, hardness and adhesion. The self-healing material of Example 8 corresponds to the "gel of the same composition except that it does not contain a structure based on a cross-linking agent" of the self-healing materials of Examples 1-7.

The self-healing materials of Examples 1 and 2 were harder, less tacky, and less deformable when cut than the self-healing material of Example 8, which did not use a cross-linking agent. In addition, the self-repairing materials of Examples 1 and 2 retained 60% or more of the self-repairing ability of the self-repairing material of Example 8.
On the other hand, the self-repairing materials of Examples 3 to 7 using a cross-linking agent having one type of polymerizable functional group were easily deformed when cut or had poor self-repairing ability. Specifically, in Example 3 using the cross-linking agent 3, the hardness and tackiness were improved, but the self-healing ability was lowered. Example 4 using the cross-linking agent 4 and Example 5 using the cross-linking agent 5 were the same. Example 6 using cross-linking agent 6 was softer than Example 8 and had high tackiness. Example 7 using cross-linking agent 7 had higher tackiness than Example 8.

(Examples 9-10)
A gel-like self-healing material was obtained in the same manner as in Examples 1 and 8 except that AA was used instead of AAm and the blending amount of each raw material was changed as shown in Table 3.
Table 4 shows the number of types of polymerizable functional groups contained in the cross-linking agent used in each example, the initial breaking elongation and tensile strength of the resulting self-healing material, the breaking elongation and tensile strength after self-healing, self-healing strength, hardness and adhesion. The self-healing material of Example 10 corresponds to the "gel of the same composition except that it does not contain a structure based on a cross-linking agent" of the self-healing material of Example 9.

The self-healing material of Example 9 was harder, less tacky, and less deformable when cut than the self-healing material of Example 10, which did not use a cross-linking agent. In addition, the self-healing material of Example 9 retained 60% or more of the self-healing ability of the self-healing material of Example 10.

Claims (5)

A self-healing material composed of a gel containing a crosslinked structure and an aqueous medium,
The crosslinked structure is obtained by cross-linking a linear polymer having side groups that can reversibly bond to each other through reversible bonds between the side groups and a structure based on a cross-linking agent,
The cross-linking agent has, in one molecule, two or more polymerizable functional groups capable of forming the main chain of the linear polymer together with the polymerizable functional groups of the monomers forming the linear polymer. ,
The self-repairing material, wherein the two or more polymerizable functional groups of the cross-linking agent include two or more types of polymerizable functional groups having different structures. 2. The self-healing material according to claim 1, wherein the ratio of said cross-linking agent to the total weight of said linear polymer and said aqueous medium is 0.01 to 10% by weight. 3. The self-repairing material according to claim 1, wherein the hardness is 110% or more of the hardness of a gel having the same composition except that it does not contain a structure based on the cross-linking agent. The self-repairing material according to any one of claims 1 to 3, wherein the adhesive force is 90% or less of the adhesive force of a gel having the same composition except that it does not contain a structure based on the cross-linking agent. The self-repairing material according to any one of claims 1 to 4, wherein the self-repairing ability is 60% or more of the self-repairing ability of a gel having the same composition except that it does not contain a structure based on the cross-linking agent.