Curable composition, cured product, laminate, and method for producing the same.

Abstract

The present invention provides a curable composition that yields a coating film with excellent hot water adhesion; a cured product of the curable composition; a laminate using the curable composition; and methods for manufacturing the same. [Solution] The curable composition of the present invention contains the following compound A and compound B. Compound A: Compounds whose (TI)² calculated by the following formula (L) is between 3.65 and 9.17 (excluding compound B). Compound B: A polyfunctional (meth)acrylate monomer having three or more (meth)acryloyl groups. (TI)² = 4 / (N × χ²) ... Equation (L) N: The number of atoms in the backbone of compound A, excluding hydrogen atoms. χ²: The second smallest eigenvalue of the Laplacian matrix representing the molecular structure of compound A.

Description

[Technical Field]

[0001] The present invention relates to curable compositions, cured products, laminates, and methods for producing the same. This application claims priority based on Japanese Patent Application No. 2022-20653, filed with the Japan Patent Office on February 14, 2022, and the contents of that application are incorporated herein by reference. [Background technology]

[0002] Resin molded products made from polymethyl methacrylate resin, polymethacrylimide resin, polycarbonate resin, polystyrene resin, acrylonitrile styrene resin, etc., are lightweight and offer excellent impact resistance as well as transparency. Resin molded products are used, for example, as components for various lamp lenses, glazing, and instrument covers in automobiles. In particular, resin molded products are frequently used for automotive headlamp lenses to meet the demands for lighter vehicles and diverse designs. However, resin molded products lack sufficient abrasion resistance, making them susceptible to surface damage from contact with hard objects, friction, scratching, etc. Surface damage to resin molded products reduces their commercial value. In addition, weather resistance is also important for automotive components.

[0003] For example, polycarbonate resin is widely used as an engineering plastic with excellent transparency, ease of molding, heat resistance, and impact resistance. In automotive applications, polycarbonate resin is used as a material for headlamp lenses, taillights, side cover lamps, glazing, and other components. However, polycarbonate resin lacks sufficient abrasion resistance, making its surface prone to scratches. Furthermore, its weather resistance is lower than other engineering plastics, which can lead to significant yellowing and surface cracking due to ultraviolet radiation.

[0004] Forming a coating film on the surface of a resin molded product can impart abrasion resistance and weather resistance. Such coatings often contain additives to enhance adhesion to the substrate. The fact that the coating maintains excellent adhesion to the substrate even after various long-term durability tests contributes to extending the lifespan of the abrasion resistance, weather resistance, and other properties imparted to the substrate. For example, Patent Documents 1 to 3 discuss coating compositions aimed at improving adhesion. Patent Document 1 proposes the use of dimethylformamide. Patent Document 2 proposes the use of dimethylformamide, N-methylpyrrolidone, cyclohexanone, and methyl acetate cellosolve. Patent Document 3 proposes the use of (meth)acrylate having a cyclic ether structure. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 9-302268 [Patent Document 2] Japanese Patent Application Publication No. 10-7939 [Patent Document 3] Japanese Patent Publication No. 2017-8200 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, the coating films obtained by curing the compositions of Patent Documents 1 to 3 have insufficient adhesion to the substrate when immersed in hot water, i.e., insufficient hot water resistance. The present invention provides a curable composition that yields a coating film with excellent hot water adhesion; a cured product of the curable composition; a laminate using the curable composition; and methods for manufacturing the same. [Means for solving the problem]

[0007] The present invention has the following aspects. [1] A curable composition containing the following compound A and the following compound B. Compound A: a compound (excluding the following compound B) having a second Mohar index calculated by the following formula (L) of 3.65 to 9.17. Compound B: a polyfunctional (meth)acrylate monomer having 3 or more (meth)acryloyl groups. (TI)2=4 / (N×χ2) ···Formula (L) In formula (L), (TI)2 is the second Mohar index; N is the number of atoms excluding hydrogen atoms in the backbone of compound A; χ2 is the second smallest value among the eigenvalues of the Laplacian matrix representing the molecular structure of compound A; the Laplacian matrix is an N-row × N-column square matrix; the value of the k-th diagonal component (k,k) from the left of the Laplacian matrix is the k-th atom Z excluding hydrogen atoms in the backbone of compound A k is the number of atoms obtained by excluding hydrogen atoms from the atoms bonded to; among the components (i,j) in the i-th row and j-th column of the off-diagonal components of the Laplacian matrix, the value in each column of the k-th row component (k,j) is the j-th atom Z excluding hydrogen atoms in the backbone of compound A j is the atom Z k is -1 when bonded to the atom Z, and when the atom Z j is the atom Z k is 0 when not bonded to; the sum of components in each row and the sum of components in each column of the Laplacian matrix is 0; N is an integer of 2 or greater; i, j and k are integers from 1 to N; i and j are different from each other. [2] The curable composition according to [1], further containing the following compound B-1. Compound B-1: a (meth)acrylate having at least one selected from the group consisting of a dendrimer structure and a hyperbranched structure (excluding the compound B described above). [3] The curable composition according to [1] or [2], wherein the viscosity of the curable composition at 25°C is 250 mPa·s or less. [4] A cured product of the curable composition according to any one of [1] to [3]. [5] A laminate comprising a substrate and a layer composed of the cured product according to [4]. [6] The laminate according to [5], wherein the substrate is a plastic substrate. [7] A method for producing a curable composition, comprising mixing a compound A selected as a compound whose second Mohar index calculated by the following formula (L) is 3.65 to 9.17 (excluding the following compound B) and the following compound B. Compound B: a polyfunctional (meth)acrylate monomer having three or more (meth)acryloyl groups. (TI)2=4 / (N×χ2) ···Formula (L) In formula (L), (TI)2 is the second Mohar index; N is the number of atoms excluding hydrogen atoms in the skeleton of compound A; χ2 is the second smallest value among the eigenvalues of the Laplacian matrix representing the molecular structure of compound A; the Laplacian matrix is an N-row×N-column square matrix; the value of the k-th diagonal component (k,k) from the left of the Laplacian matrix corresponds to the k-th atom Z excluding hydrogen atoms in the skeleton of compound A k is the number of atoms excluding hydrogen atoms among the atoms bonded to the k-th atom Z; among the i-row j-column components (i,j) of the off-diagonal components of the Laplacian matrix, the value of each column in the k-th row (k,j) corresponds to the j-th atom Z excluding hydrogen atoms in the skeleton of compound A j when said atom Z k is bonded to the aforementioned atom Z j when said atom Z k is not bonded to the aforementioned atom Z, it is 0; the sum of components in each row and the sum of components in each column of the Laplacian matrix are 0; N is an integer of 2 or more; i, j and k are integers from 1 to N; i and j are different from each other. [8] The manufacturing method described in [7], further comprising mixing compound B-1 below. Compound B-1: A (meth)acrylate having at least one selected from the group consisting of a dendrimer structure and a hyperbranched structure (excluding compound B). A method for producing a cured product, comprising curing a curable composition obtained by the manufacturing method described in [9], [7], or [8].

[10] A method for manufacturing a laminate having a base material and a layer made of a cured product, A method for producing a laminate, comprising curing a curable composition obtained by the manufacturing method described in [7] or [8] to obtain the cured product.

[11] The manufacturing method according to

[10] , wherein the substrate is a plastic substrate. [Effects of the Invention]

[0008] According to the curable composition of the present invention, a coating film with excellent hot water adhesion can be obtained. The cured product of this invention exhibits excellent resistance to hot water adhesion. The laminate of the present invention has a layer made of a cured material that has excellent resistance to hot water adhesion. According to the method for producing the curable composition of the present invention, a curable composition with excellent hot water adhesion when used as a coating film can be obtained. According to the method for producing a cured product of the present invention, a cured product with excellent resistance to hot water adhesion can be obtained. According to the method for manufacturing a laminate of the present invention, a laminate having a layer made of a cured material with excellent hot water adhesion properties can be obtained. [Modes for carrying out the invention]

[0009] The meanings of the terms are as follows: "(Meth)acrylic" is a general term for "acrylic" and "methacrylic". "(Meth)acryloyl" is a general term for "acryloyl" and "methacryloyl." "(Meth)acrylate" is a general term for "acrylate" and "methacrylate". "(meth)acryloyl group functional number" refers to the number of (meth)acryloyl groups contained in one molecule of (meth)acrylate. The "~" symbol indicating a numerical range means that the numbers before and after it are included as the lower and upper limits. The numerical ranges disclosed herein can be arbitrarily combined to form new numerical ranges.

[0010] <Curable composition> The curable composition of the present invention contains the following compound A and the following compound B. Compound A: A compound whose second Mohal index, calculated using a specific formula, is between 3.65 and 9.17 (excluding Compound B below). Compound B: A polyfunctional (meth)acrylate monomer having three or more (meth)acryloyl groups.

[0011] Below, we will describe, in order, compound A and compound B in relation to a curable composition according to one embodiment. Subsequently, we will describe other components that may constitute the curable composition, as well as the composition and properties of the curable composition.

[0012] (Compound A) Compound A is a compound whose second Mohal index, calculated using the following formula (L), is between 3.65 and 9.17 (excluding compound B, which will be discussed later). (TI)² = 4 / (N × χ²) ... Equation (L) In equation (L), (TI)2 is the second Mohal index.

[0013] In formula (L), N is the number of atoms in the skeleton of compound A excluding the hydrogen atoms. In this specification, "compound skeleton" refers to the portion of a compound's chemical structure formula obtained by removing hydrogen atoms from the constituent atoms of the molecule. The bonds between atoms in the skeleton are typically covalent bonds, but any chemical bond, such as hydrogen bonds, ionic bonds, or metallic bonds, is also acceptable. In the case of covalent bonds, the bonds between atoms in the skeleton can be single bonds, double bonds, or triple bonds.

[0014] The atoms constituting the backbone of a compound may be any atom other than hydrogen, and are not particularly limited. In one embodiment, the atoms constituting the backbone of compound A are typically carbon atoms. However, the atoms constituting the backbone of compound A are not limited to carbon atoms. The atoms constituting the backbone of compound A may be various heteroatoms such as oxygen atoms, nitrogen atoms, sulfur atoms, phosphorus atoms, boron atoms, silicon atoms, halogen atoms, etc. The number of these heteroatoms is counted in the same way as the number of carbon atoms and included in the number of atoms in the backbone of the compound.

[0015] We will explain the method of counting the number of atoms in the backbone of a compound, using several examples. For aliphatic and aromatic hydrocarbons, the number of atoms excluding hydrogen atoms is counted as the number of atoms in the skeleton. If some or all of the hydrogen atoms are replaced by halogen atoms, the number of halogen atoms is counted as the number of atoms in the skeleton. For example, hexane and cyclohexane have 6 atoms in their skeletons, chlorobenzene has 7 atoms, and 2,4-dimethylhexane has 8 atoms.

[0016] Oxygen atoms are counted in the total number of atoms in the skeleton. The oxygen atom (-O-) of the ether group (-O-) is counted in the number of atoms in the skeleton. For example, in the case of dimethyl ether (CH3OCH3), the number of atoms in the skeleton is 3. The oxygen atom of the hydroxyl group (-OH) is counted in the number of atoms in the skeleton, while the hydrogen atom of the hydroxyl group (-OH) is not counted. For example, in the case of 1-propanol (CH3CH2CH2OH), the number of atoms in the skeleton is 4. In the case of 1,2-butanediol (CH3CH2CH(OH)CH2OH), the number of atoms in the skeleton is 6. The oxygen and carbon atoms of an aldehyde group (C(=O)H) are counted in the number of atoms in the skeleton, but the hydrogen atoms of an aldehyde group (C(=O)H) are not counted. For example, in the case of acetaldehyde (CH3C(=O)H), the number of atoms in the skeleton is 3. The oxygen and carbon atoms of a ketone group (C(=O)) are counted in the number of atoms in the skeleton. For example, in the case of 2-butanone (CH3C(=O)CH2CH3), the number of atoms in the skeleton is 5. The carbon atom and two oxygen atoms of the carboxyl group (C(=O)OH) are counted in the number of atoms in the skeleton, but the hydrogen atom of the carboxyl group (C(=O)OH) is not counted. For example, in the case of acetic acid (CH3C(=O)OH), the number of atoms in the skeleton is 4. In the case of dichloroacetic acid (CHCl2C(=O)OH), the number of atoms in the skeleton is 6.

[0017] Nitrogen atoms are counted in the total number of atoms in the skeleton. For example, in the case of ethylenediamine (H2NCH2CH2NH2), the number of atoms in the skeleton is 4. The nitrogen, carbon, and oxygen atoms of an amide group are counted in the number of atoms in the skeleton. For example, in the case of acetamide (CH3CONH2), the number of atoms in the skeleton is 4.

[0018] Sulfur atoms are counted in the total number of atoms in the skeleton. For example, in the case of methanethiol (CH3SH), the number of atoms in the skeleton is 2. The sulfur atom and three oxygen atoms of the sulfonic acid group (-SO3H) are counted in the number of atoms in the skeleton, but the hydrogen atom of the sulfonic acid group (-SO3H) is not counted. For example, in the case of methanesulfonic acid (CH3SO3H), the number of atoms in the skeleton is 5.

[0019] Boron atoms are counted in the total number of atoms in the skeleton. For example, in the case of diborane (B2H6), the number of atoms in the skeleton is 2. The boron atom and the two oxygen atoms of the boronic acid group (-B(OH)2) are counted in the number of atoms in the skeleton, but the hydrogen atom of the boronic acid group (-B(OH)2) is not counted in the number of atoms in the skeleton. For example, in the case of methylboronic acid (CH3B(OH)2), the number of atoms in the skeleton is 4.

[0020] Silicon atoms are counted in the total number of atoms in the skeleton. For example, in the case of tetramethylsilane (Si(CH3)4), the number of atoms in the skeleton is 5. The silicon and oxygen atoms of the silanol group (-SiOH) are counted in the number of atoms in the skeleton, but the hydrogen atoms of the silanol group (-SiOH) are not counted. For example, in the case of trimethylsilanol ((CH3)3SiOH), the number of atoms in the skeleton is 5.

[0021] Halogen atoms are counted in the total number of atoms in the skeleton. For example, in the case of chloroform (CHCl3), the number of atoms in the skeleton is 4.

[0022] In a curable composition according to one embodiment, the number of atoms excluding hydrogen atoms in the skeleton of compound A, i.e., N, is an integer of 2 or more. Considering that the second Mohal index of compound A is in the range of 3.65 to 9.17, the value of N as the number of atoms excluding hydrogen atoms in the skeleton of compound A is preferably 2 to 50, more preferably 5 to 40, more preferably 10 to 30, more preferably 13 to 20, more preferably 14 to 19, and even more preferably 15 to 18.

[0023] In equation (L), χ² is the second smallest eigenvalue of the Laplacian matrix representing the molecular structure of compound A. The Laplacian matrix representing the molecular structure of compound A is the Laplacian matrix representation of the compound's chemical structure in graph theory. When describing the molecular structure of a compound using graph theory, the atoms that make up the compound's backbone correspond to the nodes in graph theory. Furthermore, the chemical bonds between atoms correspond to the edges in graph theory.

[0024] The graph theory of compounds and the Laplacian matrix are described in detail in the following references. The contents of the following references are incorporated by reference in this specification. References: Nenad Trinajstic, *The Laplacian Matrix in Chemistry*, *Journal of Chemical Information and Computer Sciences*, American Chemical Society, 1994, Vol. 34, Issue 2, pp. 368-376.

[0025] The Laplacian matrix used to calculate the χ² of compound A is an N x N square matrix. The value of the k-th diagonal element (k,k) from the left of this Laplacian matrix is ​​the k-th atom Z of the skeleton of compound A. k This is the number of atoms remaining after removing hydrogen atoms from the atoms bonded to it.

[0026] Here, the k-th atom Z of the compound's skeleton. k This is determined based on the locant, which is defined according to IUPAC nomenclature. The locant is a number determined sequentially from 1 according to the structure of the skeleton and the priority of the functional groups. The atom with locant number k is the k-th atom of the skeleton, Z. k k is an integer between 1 and N.

[0027] In the case of chain compounds, atom Z k This is the k-th atom, counting from the end of the skeleton. Also, in the case of cyclic compounds, atom Z k In this case, the locant is the k-th atom, meaning the locant is the k-th atom counting from the first atom. In the case of a compound with a branched structure, the atoms of the backbone of the branched chain portion are also counted in locant order, and the atoms Z k To decide.

[0028] This section explains the off-diagonal elements of the Laplacian matrix. The values ​​in each column of the k-th row component (k,j) of the off-diagonal component (i,j) in the i-th row and j-th column of the Laplacian matrix are the values ​​of the j-th atom Z of the skeleton of compound A. j The k-th atom Z k When bonded with, it is -1. On the other hand, atom Z j is atom Z k When not joined, the values ​​in each column of the k-th row component (k,j) are 0. i and j are integers from 1 to N, and i and j are distinct from each other. This is because component (i,j) is an off-diagonal matrix element.

[0029] Here, the j-th atom Z of the skeleton of compound A. j is the atom Z k Similarly, it is determined based on the locant, which is defined according to IUPAC nomenclature. The atom with locant number j is the j-th atom Z in the skeleton of compound A. j That is the case. Since k is an integer between 1 and N, we can determine the component (i,j) by determining the values ​​of each column of component (k,j) in order from row 1, row 2, ... row k ... row N.

[0030] Since the Laplacian matrix of compound A is a square matrix, when determining the component (i,j), we may determine the values ​​of each row of the component (i,k) in the kth column in order from the 1st column, the 2nd column, ..., the kth column..., the Nth column. That is, the values ​​of each row of the component (i,k) in the kth column are determined by the i-th atom Z of the skeleton of compound A. i The k-th atom Z k When bonded with atom Z, it is set to -1. i is atom Z k If it is not connected to another element, we may set it to 0 and determine the component (i,k). In this case as well, the resulting Laplacian matrix will be the same.

[0031] As described above, in the Laplacian matrix of compound A, where the diagonal elements (k,k) and elements (i,j) have been determined, the sum of the elements in each row and each column is 0. The diagonal elements (k,k) reflect the information about the number of bonding atoms at each atom in the skeleton of compound A. On the other hand, the elements (k,j) in the kth row and the kth column of element (i,k) represent the atoms Z of compound A.j , atom Z i Atom Z in k The presence or absence of a bond with is reflected. As a result, the k-th row component (k,j) and the k-th column component (i,k) of component (i,j) contain the k-th atom Z. k The positional information of the connection to is reflected in the Laplacian matrix.

[0032] The Laplacian matrix used to calculate the χ² of compound A is an N x N square matrix. The eigenvalues ​​of the Laplacian matrix are obtained as solutions to its characteristic equation. The solution to the characteristic equation becomes more complex as the order of the matrix increases. Therefore, it is preferable to use an online calculation site (for example, https: / / keisan.casio.jp / exec / system / 1505174268). In addition to calculation sites, a computer or calculation software capable of running a calculation program to find the solution to the characteristic equation may also be used.

[0033] For example, the molecular structure of 2,4-dimethylhexane can be described using the Laplacian matrix in graph theory as an 8x8 square matrix, as shown below.

[0034]

number

[0035] In determining the Laplacian matrix of 2,4-dimethylhexane, the constituent atoms of the skeleton were numbered according to Locant's method as follows.

[0036] [ka]

[0037] The second smallest eigenvalue χ² of the Laplacian matrix when describing 2,4-dimethylhexane using graph theory is 0.2137. Also, the number of atoms in the skeleton of 2,4-dimethylhexane is 8. Therefore, the second Mohal index of 2,4-dimethylhexane is calculated from the above formula (L) as follows. (TI)2=4 / (N×χ2)=4 / (8×0.2137)≒2.34

[0038] Generally, the smaller the second Mohal index of a compound, the more atoms tend to make up the backbone of that compound. It also tends to have a more branched and bulky structure. Conversely, the larger the second Mohal index, the fewer atoms tend to make up the backbone of that compound. It also tends to have a more linear structure with fewer branches.

[0039] In one embodiment of the curable composition, the second mohal index of compound A is 3.65 to 9.17. Since the second mohal index of compound A is within this range, it is believed that the hot water adhesion and humid heat adhesion of the coating film obtained from the curable composition will be improved. The detailed mechanism is unknown, but it is presumed to be as follows. Since the second Mohal index of compound A is between 3.65 and 9.17, the molecular skeleton of compound A is moderately elongated and not bulky. Compound A with such a molecular skeleton exhibits moderate affinity to the substrate, and is likely to penetrate into the substrate and swell easily. Therefore, it is thought that the contact surface area between the cured coating and the substrate interface increases significantly. As a result of the increased contact surface area, the anchoring effect is more easily obtained, and the adsorption force based on van der Waals forces, hydrogen bonding forces, etc. is increased. Therefore, it is presumed that the hot water resistance and humid heat resistance of the coating obtained from the curable composition will improve. As explained above, compound A, with a second Mohal index of 3.65 to 9.17, is considered to easily form a large surface area adhesive interface at the interface with the substrate when cured into a coating film. Therefore, the hot water resistance and humid heat resistance of the coating film are improved, and the functional coating on the substrate surface can be maintained for a long period of time.

[0040] If the second Mohal index of compound A is greater than 3.65, the molecular skeleton will not have too many branches and will have fewer bulky substituents. Therefore, the molecular cross-sectional area is less likely to become excessively large, and compound A is more likely to penetrate into the substrate and swell. If the second Mohal index of compound A is even lower than 9.17, the main chain portion of the molecular skeleton is less likely to become excessively long. Therefore, the self-association of compounds A together weakens, and a strong affinity with the substrate molecule is more likely to be expressed. As a result, compound A is thought to penetrate deep into the substrate and swell easily. From the above viewpoints, the second Mohal index of compound A is preferably 4.00 to 8.50, more preferably 4.05 to 7.39, even more preferably 4.10 to 7.29, even more preferably 4.50 to 7.13, even more preferably 5.00 to 6.71, particularly preferably 5.20 to 6.06, and most preferably 5.30 to 5.55. Compound A may be used alone, or two or more types of Compound A with different second Mohal indices may be used in combination.

[0041] As a result of further investigations, the inventors have found preferred molecular weight conditions for compound A. The molecular weight of compound A is preferably 160 to 305, more preferably 170 to 275, even more preferably 175 to 250, particularly preferably 190 to 240, and most preferably 205 to 230. The reasons why these numerical ranges are preferable are speculative, but they can be thought to be as follows. When the molecular weight is within the aforementioned numerical range, it is thought that a good balance is achieved between the dissolution or elution behavior of the substrate and the permeability into the substrate. When the molecular weight is 160 or higher, the dissolution or elution behavior of the substrate due to diffusion is less likely to occur, and it is presumed that an interface is easily formed between the cured product with a large surface area and the substrate. On the other hand, when the molecular weight is 305 or lower, the molecular size is not excessively large, and it is presumed that it is easier to maintain permeability into the substrate.

[0042] Compound A may contain various heteroatoms such as oxygen atoms, nitrogen atoms, sulfur atoms, phosphorus atoms, boron atoms, silicon atoms, and halogen atoms.

[0043] Examples of compound A containing an oxygen atom include ethers, ketones, carboxylic acids, esters containing (meth)acrylate monomers or acetate monomers, and carbonates. Examples of compound A containing a nitrogen atom include amides containing amino and acrylamide monomers, amines, and semipolar compounds containing amine oxides. Examples of compounds A containing a sulfur atom include amphoteric compounds such as thiols, thioesters, sulfonic acids, and sulfobetaines. Examples of compound A containing a phosphorus atom include amphoteric compounds such as phosphoric acid, phosphate esters, and phosphobetaine. Examples of compound A containing a boron atom include borane, boronic acid, and boronic acid ester. Examples of compound A containing silicon atoms include silanes, siloxanes, and silanols. Examples of compound A containing a halogen atom include alkanes, alkenes, and alkynes.

[0044] Compound A may be a chain compound consisting of a linear or branched chain structure, a cyclic compound consisting of a cyclic structure, or a compound consisting of both chain and cyclic structures. Furthermore, some of the bonds constituting compound A may be unsaturated bonds, or all of the bonds may be saturated bonds.

[0045] The cyclic structure may be an aliphatic ring, an aromatic ring, a non-aromatic heterocycle, or an aromatic heterocycle. Furthermore, the cyclic structure may be a monocycle or a polycycle of two or more rings. Of these, aliphatic rings and non-aromatic heterocycles are more preferred from the viewpoint of weather resistance, and aliphatic rings are even more preferred.

[0046] An aliphatic ring is a monocyclic or polycyclic ring consisting of two or more rings. Some of the bonds constituting an aliphatic ring may be unsaturated bonds. A bicyclic aliphatic ring may have some aromaticity. Examples of aliphatic rings include cycloalkanes, cycloalkenes, cycloalkynes, bicycloalkanes, and tricycloalkanes.

[0047] An aromatic ring is a monocyclic or polycyclic ring (two or more rings) that possesses aromatic properties. Examples of aromatic rings include benzene rings and naphthalene rings.

[0048] A non-aromatic heterocycle is a monocyclic or polycyclic molecule having one to four identical or different heteroatoms selected from the group consisting of nitrogen, oxygen, and sulfur atoms. Some of the bonds constituting a non-aromatic heterocycle may be unsaturated bonds. A bicyclic non-aromatic heterocycle may have some aromaticity. Examples of non-aromatic heterocyclic groups include azilidinyl, azetidinyl, pyrrolidinyl, piperidinyl, dihydropyridyl, oxetanyl, tetrahydrofuryl, dihydrofuryl, tetrahydropyranyl, dihydropyranyl, tetrahydrothienyl, tetrahydrothiopyranyl, dihydrothiopyranyl, piperazinyl, dihydropyrazyl, morpholinyl, thiomorpholinyl, dihydroindolyl, dihydroisoindolyl, dihydrobenzofuryl, dihydroisobenzofuryl, tetrahydrobenzoxazolyl, dihydrophropyridyl, dihydropyrazolomorpholinyl, pyridinodioxanyl, dihydroazabenzofuryl, dihydroazaisobenzofuryl, and dihydroazaindolyl.

[0049] The non-aromatic heterocycle may also be a cyclic amino acid. A "cyclic amino acid" has a bonding hand on the nitrogen atom that forms the ring structure of the non-aromatic heterocycle. Examples of cyclic amino acids include azetidine-1-yl, pyrrolidine-1-yl, piperidine-1-yl, morpholine-4-yl, thiomorpholine-4-yl, and piperazine-1-yl.

[0050] An aromatic heterocycle is a monocycle or polycycle of two or more rings that is aromatic and has one to four identical or different heteroatoms selected from the group consisting of nitrogen, oxygen, and sulfur atoms. Examples of aromatic heterocycle groups include pyrrolyl, furyl, thienyl, pyrazolyl, imidazolyl, oxazolyl, thiazolyl, pyridyl, pyridadinyl, pyrimidinyl, pyrazyl, indolyl, isoindolyl, benzofuryl, benzothienyl, indazolyl, benzimidazolyl, benzoxazolyl, benzothiazolyl, quinolyl, isoquinolyl, sinnolinyl, quinazolinyl, quinoxalyl, pyrrolopyridyl, and imidazolopyridyl.

[0051] As compound A, acetate and (meth)acrylate monomers are preferred. Examples of acetates include methyl carbitol acetate, ethyl carbitol acetate, propyl carbitol acetate, butyl carbitol acetate, pentyl carbitol acetate, hexyl carbitol acetate, heptyl carbitol acetate, and octyl carbitol acetate. However, acetates are not limited to these examples.

[0052] Examples of (meth)acrylate monomers include methoxyethoxyethyl acrylate, ethoxyethoxyethyl acrylate, propiooxyethoxyethyl acrylate, butoxyethoxyethyl acrylate, pentoxyethoxyethyl acrylate, hexyloxyethoxyethyl acrylate, heptoxyethoxyethyl acrylate, octoxyethoxyethyl acrylate, caprolactone-modified (1 mol) ethyl acrylate, caprolactone-modified (2 mol) ethyl acrylate, methoxytriethylene glycol acrylate, ethoxy-triethylene glycol acrylate, propiooxy-triethylene glycol acrylate, butoxy-triethylene glycol acrylate, pentoxy-triethylene glycol acrylate, and hexyloxy-triethylene Examples include methyl glycol acrylate, heptoxy-triethylene glycol acrylate, octoxy-triethylene glycol acrylate, 2-acryloyloxyethyl ethyl carbonate, 2-acryloyloxyethyl propyl carbonate, 2-acryloyloxyethyl butyl carbonate, 4-acryloyloxybutyl ethyl carbonate, 4-acryloyloxybutyl propyl carbonate, 4-acryloyloxybutyl butyl carbonate, 1,4-butanediol diacrylate, 1,5-pentanediol diacrylate, 1,6-hexanediol diacrylate, 1,7-heptanediol diacrylate, 1,8-octanediol diacrylate, 1,9-nonanediol diacrylate, and dimethylol-tricyclodecane diacrylate. However, (meth)acrylate monomers are not limited to these examples.

[0053] In particular, from the viewpoint of linearity of molecular structure, compound A is preferably one that contains at most two substituents having polymerization activity. For example, ethyl carbitol acetate, butyl carbitol acetate, ethoxyethoxyethyl acrylate, butoxyethoxyethyl acrylate, hexyloxyethoxyethyl acrylate, caprolactone-modified (1 mol) ethyl acrylate, methoxy-triethylene glycol acrylate, butoxy-triethylene glycol acrylate, 4-acryloyloxybutyl ethyl carbonate, 4-acryloyloxybutyl butyl carbonate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, and dimethylol-tricyclodecane diacrylate are preferred.

[0054] (Compound B) Compound B is a polyfunctional (meth)acrylate monomer having three or more (meth)acryloyl groups (except for compound C, which is described later). In relation to compound A, if a compound is a "polyfunctional (meth)acrylate monomer having three or more (meth)acryloyl groups," then that compound is classified as compound B, even if its second Mohal index is between 3.65 and 9.17.

[0055] One embodiment of the curable composition contains compound B as one of the radical polymerizable compounds. Because the curable composition contains compound B, it exhibits good polymerization activity upon irradiation with active energy rays. As a result, the crosslinking density increases, and the scratch resistance of the coating film improves.

[0056] As compound B, any conventionally known compound containing at least three polymerizable functional groups in one molecule can be used from the viewpoint of scratch resistance and weather resistance. Examples include poly(meth)acrylate, polyester poly(meth)acrylate, epoxy poly(meth)acrylate, and poly[(meth)acryloyloxyalkyl](iso)cyanurate.

[0057] The number of (meth)acryloyl functional groups in compound B is preferably 3 to 20. From the viewpoint of curability and scratch resistance, the number of (meth)acryloyl functional groups in compound B is preferably 4 or more, more preferably 5 or more, and even more preferably 6 or more. Furthermore, from the viewpoint of weather resistance and curing shrinkage, the number of (meth)acryloyl functional groups in compound B is preferably 18 or less, more preferably 16 or less, and even more preferably 14 or less.

[0058] Examples of compound B include poly[(meth)acryloyloxyalkyl](iso)cyanurate, polyester poly(meth)acrylate, and poly(meth)acrylate. Examples of poly[(meth)acryloyloxyalkyl](iso)cyanurates include isocyanuric acid EO-modified tri(meth)acrylate. Examples of polyester poly(meth)acrylates include polyester tri(meth)acrylate, polyester tetra(meth)acrylate, polyester penta(meth)acrylate, and polyester hexa(meth)acrylate. Examples of poly(meth)acrylates include glycerin tri(meth)acrylate, glycerin EO-modified tri(meth)acrylate, glycerin PO-modified tri(meth)acrylate, glycerin caprolactone-modified tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, EO-modified trimethylolpropane tri(meth)acrylate, PO-modified trimethylolpropane tri(meth)acrylate, caprolactone-modified trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, EO-modified pentaerythritol tri(meth)acrylate, PO-modified pentaerythritol tri(meth)acrylate, caprolactone-modified pentaerythritol tri(meth)acrylate, and pentaerythritol. Examples include tetra(meth)acrylate, EO-modified pentaerythritol tetra(meth)acrylate, PO-modified pentaerythritol tetra(meth)acrylate, caprolactone-modified pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, EO-modified dipentaerythritol penta(meth)acrylate, PO-modified dipentaerythritol penta(meth)acrylate, caprolactone-modified dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, EO-modified dipentaerythritol hexa(meth)acrylate, PO-modified dipentaerythritol hexa(meth)acrylate, and caprolactone-modified dipentaerythritol hexa(meth)acrylate. "EO" stands for ethylene oxide, and "PO" stands for propylene oxide. Compound B may be used alone or in combination of two or more types.

[0059] In particular, from the viewpoint of balancing scratch resistance and weather resistance (resistance to yellowing and cracking), compound B is preferably isocyanuric acid EO-modified tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, caprolactone-modified polyfunctional (meth)acrylate, or polyfunctional (meth)acrylate having a dipentaerythritol skeleton, with caprolactone-modified polyfunctional (meth)acrylate having a dipentaerythritol skeleton being more preferred.

[0060] (Compound B-1) In one embodiment, the curable composition preferably further contains compound B-1 in addition to compound A and compound B. Compound B-1: A (meth)acrylate having at least one selected from the group consisting of dendrimer structures and hyperbranched structures (excluding the aforementioned compound B and compound C described later).

[0061] In relation to compound A, any compound that falls under the category of "(meth)acrylate having at least one selected from the group consisting of a dendrimer structure and a hyperbranched structure" shall be classified as compound B-1, even if its second Mohal index is between 3.65 and 9.17.

[0062] Compound B-1 contributes to improving the flexural resistance of the cured product of the curable composition according to one embodiment. Furthermore, compound B-1 also contributes to reducing the viscosity of the curable composition according to one embodiment. Therefore, when applying this curable composition to a substrate using an air spray, a good appearance can be obtained after coating even with a small amount of diluting organic solvent. This reduces volatile organic compound (VOC) components and thus lowers the environmental impact.

[0063] A dendrimer structure refers to a structure in which a branched structure further branches to form a multi-layered branched structure, and these branched structures spread out radially. A hyperbranch structure refers to a structure in which the multiple branching structures described above extend in a branching manner in one or more predetermined directions, rather than radially.

[0064] Compound B-1 is a polyfunctional (meth)acrylate having (meth)acryloyl groups at multiple tip portions of the multi-branched structure. From the viewpoint of curability, the number of (meth)acryloyl functional groups in compound B-1 is preferably 4 or more, and more preferably 6 or more. Furthermore, from the viewpoint of curing shrinkage, the number of (meth)acryloyl functional groups in compound B-1 is preferably 20 or less, and more preferably 18 or less.

[0065] Compound B-1 may be synthesized by various methods or may be a commercially available product. For example, one method for synthesizing compound B-1 is described in Japanese Patent Publication No. 2016-190998.

[0066] Examples of (meth)acrylates having a dendrimer structure include Viscoat® #1000, SIRIUS-501, and SUBARU-501, all manufactured by Osaka Organic Chemical Industry Co., Ltd. Examples of (meth)acrylates having a hyperbranch structure include CN2302, CN2303, and CN2304 manufactured by SARTOMER.

[0067] As compound B-1, from the viewpoint of improving spray coating properties by further lowering the viscosity of the curable composition, Viscoat #1000 manufactured by Osaka Organic Chemical Industry Co., Ltd., and CN2302, CN2303, and CN2304 manufactured by SARTOMER are preferred.

[0068] From the viewpoint of spray coating properties, the viscosity (at 25°C) of compound B-1 is preferably 10,000 mPa·s or less, more preferably 7,000 mPa·s or less, even more preferably 4,000 mPa·s or less, and even more preferably 2,000 mPa·s or less. Furthermore, from the viewpoint of curability, the viscosity (at 25°C) of compound B-1 is preferably 10 mPa·s or more, more preferably 20 mPa·s or more, even more preferably 40 mPa·s or more, and even more preferably 60 mPa·s or more. The viscosity of compound B-1 (at 25°C) was measured at 25°C using an E-type viscometer.

[0069] (Compound C) In one embodiment, the curable composition preferably further contains compound C as one of the radical polymerizable compounds, in addition to compound A and compound B. Compound C: A (meth)acrylate having a (meth)acryloyl group and a urethane bond.

[0070] In relation to compound A, if a compound is a "(meth)acrylate having a (meth)acryloyl group and a urethane bond," then that compound is classified as compound C, even if its second Mohal index is between 3.65 and 9.17. Compound C contains urethane bonds, which improves the toughness of the coating film. Furthermore, it improves the weather resistance and adhesion of the cured product of the curable composition after durability testing.

[0071] As compound C, a urethane (meth)acrylate having two or more urethane bonds and two or more (meth)acryloyloxy groups in one molecule is preferred. For example, the following urethane (meth)acrylate (C1) is preferred. Urethane (meth)acrylate (C1): A reaction product of a hydroxyl group-containing (meth)acrylate (C1), a polyisocyanate (C2), and a polyol (C3) having two or more hydroxyl groups in one molecule.

[0072] The hydroxyl group-containing (meth)acrylate (c1) is not particularly limited as long as it is a (meth)acrylate having a hydroxyl group and a (meth)acryloyloxy group. Examples include 2-hydroxyethyl acrylate (HEA), 2-hydroxyethyl methacrylate (HEMA), 2-hydroxypropyl acrylate (HPA), 2-hydroxypropyl methacrylate (HPMA), 2-hydroxybutyl acrylate (HBA), 4-hydroxybutyl acrylate (4-HBA), 2-hydroxybutyl methacrylate (HBMA), a 1 mol adduct of HEA to caprolactone (Praxel® FA1 from Daicel Corporation), a 2 mol adduct of HEA to caprolactone (Praxel FA2D), a 5 mol adduct of HEA to caprolactone (Praxel FA5), a 10 mol adduct of HEA to caprolactone (Praxel FA10L), and compounds whose skeleton is mono or polypentaerythritol. Examples of compounds whose skeleton is mono- or polypentaerythritol include pentaerythritol tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, and dipentaerythritol penta(meth)acrylate. The hydroxyl group-containing (meth)acrylate (c1) may be used alone or in combination of two or more types.

[0073] Among the hydroxyl group-containing (meth)acrylates (c1), 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, 4-hydroxybutyl acrylate, pentaerythritol triacrylate, 1 mol caprolactone adduct of HEA manufactured by Daicel Corporation (Praxel FA1), and 2 mol caprolactone adduct of HEA (Praxel FA2D) are preferred from the viewpoint of ease of availability, reactivity, and solubility in curable compositions. 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, and 2-hydroxybutyl acrylate are more preferred, and 2-hydroxyethyl acrylate is even more preferred.

[0074] Polyisocyanate (C2) is not particularly limited as long as it is a polyisocyanate having two or more isocyanate groups in one molecule. For example, Aliphatic polyisocyanates such as hexamethylene diisocyanate (HDI), trimethylhexamethylene diisocyanate (TMHDI), and lysine diisocyanate; Alicyclic polyisocyanates such as norbornane diisocyanate (NBDI), transcyclohexane-1,4-diisocyanate, isophorone diisocyanate (IPDI), bis(isocyanate-methyl)cyclohexane (hydrogenated XDI), and dicyclohexylmethane diisocyanate (hydrogenated MDI); Aromatic polyisocyanates such as 2,4-tolylene diisocyanate (2,4-TDI), 2,6-tolylene diisocyanate (2,6-TDI), 4,4'-diphenylmethane diisocyanate (4,4'-MDI), 2,4'-diphenylmethane diisocyanate (2,4'-MDI), 1,4-phenylene diisocyanate, polymethylene polyphenylene polyisocyanate, xylylene diisocyanate (XDI), tetramethyl xylylene diisocyanate (TMXDI), tollidine diisocyanate (TODI), 1,5-naphthalene diisocyanate (NDI), and triphenylmethane triisocyanate; These isocyanurate, adduct, and biuret compounds; These are some examples. Polyisocyanate (c2) may be used alone or in combination of two or more types.

[0075] From the viewpoint of weather resistance, aliphatic polyisocyanates and alicyclic polyisocyanates are preferred as polyisocyanates (c2), and hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), bis(isocyanate methyl)cyclohexane (hydrogenated XDI), dicyclohexylmethane diisocyanate (hydrogenated MDI), isocyanurate of hexamethylene diisocyanate manufactured by Asahi Kasei Corporation (product name: Duranate TPA-100), adduct of hexamethylene diisocyanate (product name: Duranate P301-75E), biuret of hexamethylene diisocyanate (product name: Duranate 24A-100), and bifunctional type of hexamethylene diisocyanate (product name: Duranate A-201H) are more preferred. In particular, alicyclic polyisocyanates are more preferred from the viewpoint of scratch resistance, and dicyclohexylmethane diisocyanate (hydrogenated MDI) is even more preferred.

[0076] Polyol (c3) is not particularly limited as long as it is a polyol having two or more hydroxyl groups in one molecule. Examples include ethylene glycol, propylene glycol, diethylene glycol, butylene glycol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 3,3'-dimethylolheptane, polyoxyethylene glycol, polyoxypropylene glycol, polyoxybutylene glycol, polycaprolactone polyol (polycaprolactone diol, etc.), polytetramethylene ether glycol (PTMG), polycarbonate polyol (polycarbonate diol, etc.), and lactone polyol (such as 4-hydroxy-N-(2-hydroxyethyl)-N-methylbutanamide obtained by reacting γ-butyrolactone with N-methylethanolamine). In particular, from the viewpoint of weather resistance, polycaprolactone polyol, polycarbonate polyol, and lactone-based polyol are preferred, with polycarbonate polyol being more preferred. Furthermore, from the viewpoint of improving the flexibility of the coating film and making it less prone to cracking, polyoxyethylene glycol, polyoxybutylene glycol, and polytetramethylene ether glycol (PTMG) are preferred, with polytetramethylene ether glycol being more preferred. Polyol (c3) may be used alone or in combination of two or more types.

[0077] A commercially available polyol (C3) may be used. Examples of commercially available polycarbonate polyols include, Kuraray Polyol C-590, Kuraray Polyol C-770, Kuraray Polyol C-1050, Kuraray Polyol C-1090, Kuraray Polyol C1065N, Kuraray Polyol C-1015N, Kuraray Polyol C-2090, and Kuraray Polyol C-3090, all manufactured by Kuraray Co., Ltd. Duranol T-5650E, Duranol T-5650J, Duranol T-5651, Duranol T-5652, Duranol G-4671, Duranol G-4672, Duranol G3450J, Duranol G3452, all manufactured by Asahi Kasei Corporation; Beneviol NL1010DB, Beneviol NL2010DB, Beneviol NL3010DB, Beneviol NL1005B, Beneviol NL2005B, Beneviol NL1030B, Beneviol HS0830B, Beneviol HS0840B, Beneviol HS0840H, Beneviol HS0850H, all manufactured by Mitsubishi Chemical Corporation. These are some examples.

[0078] Examples of commercially available polytetramethylene ether glycols include, PTMG250, PTMG650, PTMG1000, PTMG2000, PTMG3000, manufactured by Mitsubishi Chemical Corporation; PTMEG #220, PTMEG #650, PTMEG #1000, PTMEG #1400, PTMEG #2000 manufactured by Mihama Co., Ltd. PTG-650, PTG-850SN, and PTG-3000, manufactured by Hodogaya Chemical Co., Ltd. These are some examples.

[0079] Urethane (meth)acrylate (C1) is obtained by reacting a hydroxyl group-containing (meth)acrylate (C1), a polyisocyanate (C2), and a polyol (C3). The reaction conditions are preferably under heating. For example, a reaction temperature of 70°C for a reaction time of 8 hours is one possible condition.

[0080] For example, urethane (meth)acrylate (C1) is: A reaction product of a polycarbonate polyol, a diisocyanate compound having an alicyclic structure, and a mono(meth)acrylate monomer having a hydroxyl group; A reaction product of polytetramethylene ether glycol, 4-hydroxy-N-(2-hydroxyethyl)-N-methylbutanamide, a diisocyanate compound having an alicyclic structure, and a mono(meth)acrylate monomer having a hydroxyl group; It is preferable.

[0081] From the viewpoint of improving spray coating properties by further lowering the viscosity of the curable composition, the mass-average molecular weight (Mw) of compound C is preferably 8000 or less, and more preferably 6000 or less. Furthermore, from the viewpoint of the flexural resistance of the cured product, the mass-average molecular weight (Mw) of compound C is preferably 500 or more, and more preferably 1000 or more. Therefore, the mass-average molecular weight (Mw) of compound C is preferably 500 to 8000, and more preferably 1000 to 6000. The mass-average molecular weight (Mw) of compound C is a value equivalent to standard polystyrene, measured by gel permeation chromatography (GPC).

[0082] The number of (meth)acryloyl functional groups in compound C is preferably 2 to 15, more preferably 2 to 10, even more preferably 2 to 6, particularly preferably 2 to 4, and most preferably 2. When the number of (meth)acryloyl functional groups in compound C is within the above numerical range, it is easier to achieve both scratch resistance and weather resistance.

[0083] (Other monomers) The curable composition according to one embodiment of the present invention may further contain other monomers, such as compounds having a (meth)acryloyl group other than compound A, compound B, compound B-1, and compound C. Other monomers are not particularly limited. Examples include linear aliphatic hydrocarbon (meth)acrylates, branched aliphatic hydrocarbon (meth)acrylates, cyclic aliphatic hydrocarbon (meth)acrylates, and hydroxyl group-containing (meth)acrylates. It is preferable that the other monomers have at least one polymerization-active group in their molecular backbone. Other monomers may be used individually or in combination of two or more.

[0084] From the viewpoint of improving spray coating properties by further lowering the viscosity of the curable composition, other monomers that are preferred include linear aliphatic hydrocarbon (meth)acrylates, branched aliphatic hydrocarbon (meth)acrylates, and cyclic aliphatic hydrocarbon (meth)acrylates. Examples include isobutyl acrylate, t-butyl acrylate, isononyl acrylate, isodecyl acrylate, 2-ethylhexyl acrylate, isostearyl acrylate, and isobornyl acrylate. Among these, 2-ethylhexyl acrylate and isostearyl acrylate are preferred from the viewpoint of viscosity reduction effect.

[0085] (Other ingredients) The curable composition may further contain other components besides compound A, compound B, compound B-1, compound C, and other monomers. Other components include, for example, UV absorbers, photopolymerization initiators, organic solvents, and additives. However, other components are not limited to these examples. In relation to compound A, if any of the other components listed below have a second Mohal index of 3.65 to 9.17, that compound shall be considered compound A.

[0086] Let me explain UV absorbers. UV absorbers can impart the effect of absorbing ultraviolet rays contained in sunlight to the cured product of a curable composition. When a curable composition contains a UV absorber, the weather resistance of the cured product of the curable composition is further improved.

[0087] The UV absorber is not particularly limited as long as it can absorb ultraviolet light. It is preferable that it can be uniformly dissolved in the curable composition and has high UV absorption capacity.

[0088] Examples of UV absorbers include, Benzophenone-based UV absorbers such as 2-hydroxybenzophenone, 5-chloro-2-hydroxybenzophenone, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octyloxybenzophenone, 4-dodecyloxy-2-hydroxybenzophenone, 2-hydroxy-4-octadecyloxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, and 2,2'-dihydroxy-4,4'-dimethoxybenzophenone; Benzotriazole-based UV absorbers such as 2-(2-hydroxy-5-methylphenyl)benzotriazole, 2-(2-hydroxy-5-tert-butylphenyl)benzotriazole, 2-(2-hydroxy-3,5-di-tert-butylphenyl)-5-chlorobenzotriazole, 2-(2-hydroxy-3,5-di-tert-butylphenyl)benzotriazole, 2-(2-hydroxy-5-tert-octylphenyl)benzotriazole, and 2-(2-hydroxy-5-(2-methacryloyloxyethyl)phenyl)-2H-benzotriazole; 2-[4-[(2-hydroxy-3-dodecyloxypropyl)oxy]-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2-[4-[(2-hydroxy-3-tridecyloxypropyl)oxy]-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2-[4-[(2-hydroxy-3-(2'-ethyl)hexyl)oxy]-2- Hydroxyphenyltriazine-based UV absorbers such as droxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2,4-bis(2-hydroxy-4-butyroxyphenyl)-6-(2,4-bis-butyroxyphenyl)-1,3,5-triazine, and 2-(2-hydroxy-4-[1-octyroxycarbonylethoxy]phenyl)-4,6-bis(4-phenylphenyl)-1,3,5-triazine; Examples include phenyl salicylate, p-tert-butylphenyl salicylate, p-(1,1,3,3-tetramethylbutyl)phenyl salicylate, 3-hydroxyphenylbenzoate, and phenylene-1,3-dibenzoate. UV absorbers may be used individually or in combination of two or more types.

[0089] In particular, from the viewpoint of maintaining UV absorption ability in the cured product over a long period of time, at least one selected from the group consisting of 2-[4-[(2-hydroxy-3-dodecyloxypropyl)oxy]-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2-[4-[(2-hydroxy-3-(2-ethyl)hexyl)oxy]-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2,4-bis(2-hydroxy-4-butyroxyphenyl)-6-(2,4-bis-butyroxyphenyl)-1,3,5-triazine, and 2-(2-hydroxy-4-[1-octyroxycarbonylethoxy]phenyl)-4,6-bis(4-phenylphenyl)-1,3,5-triazine is preferred as the UV absorber.

[0090] Furthermore, from the viewpoint of preventing UV degradation of the substrate, a hydroxyphenyltriazine-based UV absorber having an absorbance of 1.0 or higher at 350 nm is preferred. For example, at least one selected from the group consisting of 2-[4-[(2-hydroxy-3-(2-ethyl)hexyl)oxy]-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2,4-bis(2-hydroxy-4-butyroxyphenyl)-6-(2,4-bis-butyroxyphenyl)-1,3,5-triazine, and 2-(2-hydroxy-4-[1-octyroxycarbonylethoxy]phenyl)-4,6-bis(4-phenylphenyl)-1,3,5-triazine is more preferred. Absorbance is measured using a Hitachi U-1900 spectrophotometer.

[0091] As for the ultraviolet absorber, from the viewpoint of solubility in the curable composition and weather resistance, compounds derived from at least one selected from the group consisting of benzophenone, benzotriazole, hydroxyphenyltriazine, phenyl salicylate, and phenyl benzoate are preferred, and among these compounds, compounds with a maximum absorption wavelength in the range of 240 to 380 nm are more preferred.

[0092] From the viewpoint of being able to be included in large quantities in the curable composition, benzophenone-based UV absorbers, benzotriazole-based UV absorbers, and hydroxyphenyltriazine-based UV absorbers are more preferred as UV absorbers. From the standpoint of minimizing bleed-out in the cured product, benzotriazole-based UV absorbers and hydroxyphenyltriazine-based UV absorbers are more preferable as UV absorbers. Bleed-out is a phenomenon in which the UV absorber precipitates on the surface of the cured product, causing the surface to whiten. From the viewpoint of preventing yellowing of substrates such as polycarbonate resin, hydroxyphenyltriazine-based ultraviolet absorbers are even more preferred as ultraviolet absorbers.

[0093] I will now explain photopolymerization initiators. In one embodiment, when ultraviolet light is used for the curing reaction of the curable composition, it is preferable that the curable composition further contains a photopolymerization initiator. When the curable composition contains a photopolymerization initiator, the curable composition can be sufficiently cured by ultraviolet light even if an ultraviolet absorber is present. However, in one embodiment, when the curable composition is cured with active energy rays other than ultraviolet light (such as electron beams), a photopolymerization initiator is not necessarily required. The photopolymerization initiator is not particularly limited as long as it has good solubility in the curable composition and can initiate polymerization of acrylic monomers or oligomers by ultraviolet irradiation.

[0094] Examples of photopolymerization initiators include, Carbonyl compounds such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, acetoin, butyroin, toluoin, benzyl, benzophenone, p-methoxybenzophenone, diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, methylphenylglyoxylate, ethylphenylglyoxylate, 4,4-bis(dimethylaminobenzophenone), 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexylphenyl ketone, and 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one; Sulfur compounds such as tetramethylthiuram disulfide; Azo compounds such as azobisisobutyronitrile and azobis-2,4-dimethylvaleronitrile; Peroxide compounds such as benzoyl peroxide and ditert-butyl peroxide; Acylphosphine oxide compounds such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide and bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide; These are some examples.

[0095] In particular, from the viewpoint of polymerizability, benzophenone, methylphenylglyoxylate, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexylphenyl ketone, 2,2-dimethoxy-1,2-diphenylethane-1-one, and 2,4,6-trimethylbenzoyldiphenylphosphine oxide are preferred as photopolymerization initiators. A single photopolymerization initiator may be used alone, or two or more may be used in combination.

[0096] As a photopolymerization initiator, one having an absorption maximum at a wavelength of 360-400 nm is preferred. When such a photopolymerization initiator is used, radicals are generated by ultraviolet light when the curable composition is cured with ultraviolet light, allowing polymerizable compounds (polymerizable monomers, polymerizable oligomers, etc.) to be efficiently polymerized even deep within the coating film. As a result, it is easy to obtain a cured product with excellent adhesion to the substrate.

[0097] Let's discuss organic solvents. The curable composition may also contain organic solvents as other components. When a curable composition contains organic solvents, the uniform solubility and dispersion stability of its components tend to improve. Furthermore, the adhesion of the cured product to the substrate, as well as the smoothness and uniformity of the cured product, tend to improve.

[0098] The type of organic solvent is not particularly limited. Examples include alcohols, hydrocarbons, halogenated hydrocarbons, ethers, ketones, esters, and polyhydric alcohol derivatives. Organic solvents may be used individually or in combination of two or more types.

[0099] Let's discuss additives. The curable composition may further contain additives as needed. Examples of additives include light stabilizers, antioxidants, anti-yellowing agents, bluing agents, pigments, leveling agents, defoaming agents, thickeners, anti-settling agents, antistatic agents, and anti-fogging agents. However, the additives are not limited to these examples.

[0100] (solid content concentration) The solid content concentration of the curable composition is preferably 50 to 100% by mass, more preferably 60 to 95% by mass, and even more preferably 70 to 90% by mass, from the viewpoint of environmental impact and spray coating properties.

[0101] The solid content concentration is the mass ratio of the remainder (solid content) of the curable composition after removing volatile components, relative to the total mass of the curable composition. The solid content concentration is measured using the method specified in GB / T 34675-2017 Non-volatile content measurement method. More specifically, the solid content concentration is determined by the following procedure. (1) Place the aluminum tray in a dryer heated to 110°C for 30 minutes, then cool it in a desiccator and record its weight (W). (2) Weigh 0.2 ± 0.1 g of the curable composition and record the weight: W1. (3) Place the sample immediately in a dryer heated to 50°C for 30 minutes to dry it. (4) After heating is complete, the curable composition is cured in a curing device while still on the aluminum tray. (5) Place the cured material in a dryer heated to 110°C for 60 minutes to dry. (6) After cooling in the desiccator, record the remaining weight: W2. (7) Calculate the solid content concentration: NV according to the following formula (α). NV (mass%)=((W2-W) / (W1-W))×100...Formula (α)

[0102] (Viscosity (25℃)) The viscosity (at 25°C) of the curable composition is preferably 250 mPa·s or less, more preferably 150 mPa·s or less, and even more preferably 100 mPa·s or less. When the viscosity (at 25°C) of the curable composition is 250 mPa·s or less, the spray coating properties are improved even when the solid content concentration of the curable composition is relatively high, at 60% by mass or more. Furthermore, from the viewpoint of preventing dripping after painting, the viscosity of the curable composition (at 25°C) is preferably 20 mPa·s or higher. The viscosity of the curable composition (at 25°C) is the value measured at 25°C using an E-type viscometer.

[0103] The components and quantities of the curable composition can be analyzed using methods such as nuclear magnetic resonance (NMR) and infrared spectroscopy (IR). Furthermore, the components of the cured product can be analyzed using methods such as time-of-flight mass spectrometry (TOF-SIMS), X-ray photoelectron spectroscopy (ESCA), X-ray fluorescence, and infrared spectroscopy (IR).

[0104] (composition) The proportion of compound A is preferably 1 to 50% by mass of the total mass of compound A, compound B, compound B-1, compound C, and other monomers. When the proportion of compound A is within the above numerical range, the adhesion of the coating film to the substrate is further improved even after the durability test. From the viewpoint of adhesion after the durability test, the proportion of compound A is preferably 3 to 35% by mass, more preferably 5 to 30% by mass, even more preferably 6 to 25% by mass, and particularly preferably 7 to 25% by mass, of the total mass of compound A, compound B, compound B-1, compound C, and other monomers.

[0105] The proportion of compound B is preferably 5 to 80% by mass of the total mass of compound A, compound B, compound B-1, compound C, and other monomers. When the proportion of compound B is within the above numerical range, the scratch resistance of the cured film is further improved. From the viewpoint of weather resistance (crack resistance) and heat resistance of the cured film, the proportion of compound B is more preferably 10 to 70% by mass, even more preferably 20 to 65% by mass, particularly preferably 25 to 60% by mass, and most preferably 30 to 50% by mass, of the total mass of compound A, compound B, compound B-1, compound C, and other monomers.

[0106] The proportion of compound B-1 is preferably 0 to 70% by mass of the total mass of compound A, compound B, compound B-1, compound C, and other monomers. When the proportion of compound B-1 is within the above numerical range, the viscosity of the curable composition tends to decrease, and the spray coating properties tend to improve. From the viewpoint of spray coating properties, the proportion of compound B-1 is more preferably 1 to 50% by mass of the total mass of compound A, compound B, compound B-1, compound C, and other monomers, even more preferably 5 to 40% by mass, particularly preferably 10 to 35% by mass, and most preferably 15 to 30% by mass.

[0107] The proportion of compound C is preferably 0 to 70% by mass of the total mass of compound A, compound B, compound B-1, compound C, and other monomers. When the proportion of compound C is within the above numerical range, the adhesion after weather resistance and durability testing of the cured product is further improved. In addition, the viscosity of the curable composition tends to decrease, and the spray coating properties are further improved. From the viewpoint of suppressing the bleed-out of the ultraviolet absorber, the proportion of compound C is more preferably 5 to 50% by mass of the total mass of compound A, compound B, compound B-1, compound C, and other monomers, even more preferably 10 to 40% by mass, particularly preferably 13 to 35% by mass, and most preferably 15 to 30% by mass.

[0108] The proportion of the ultraviolet absorber is preferably 0.05 to 20 parts by mass, more preferably 1 to 17 parts by mass, and even more preferably 5 to 15 parts by mass, relative to the total mass of compound A, compound B, compound B-1, compound C, and other monomers. If the proportion of UV absorber is above the lower limit, the weather resistance of the cured product of the curable composition is further improved. If the proportion of UV absorber is below the upper limit, the curability is further improved.

[0109] From the viewpoint of obtaining a sufficient degree of polymerization, the proportion of the photopolymerization initiator is preferably 0.05 to 25 parts by mass, and more preferably 0.1 to 20 parts by mass, relative to the total mass of compound A, compound B, compound B-1, compound C, and other monomers. From the viewpoint of curability, 0.3 to 15 parts by mass is even more preferred.

[0110] (Manufacturing method) The method for producing the curable composition of the present invention involves mixing compound A, selected as a compound having a second Mohal index of 3.65 to 9.17, with compound B. Various types of stirrers can be used during mixing. It is also preferable to mix compound A and compound B uniformly. During mixing, compound B-1, compound C, other monomers, and other components may be further mixed as needed. Details and preferred embodiments of Compound A, Compound B, Compound B-1, Compound C, other monomers, and other components are as described above. When selecting compound A, it is preferable to use a computer to calculate the second Mohal index.

[0111] (Application) The curable composition of the present invention exhibits excellent resistance to hot water adhesion. Furthermore, the curable composition according to one embodiment exhibits excellent spray coating properties and excellent resistance to moisture and heat adhesion. Therefore, the curable composition according to one embodiment can be suitably used for applications such as hard coats for various lamp lenses in automobiles, hard coats for instruments, hard coats for grilles, and hard coats for exteriors.

[0112] <Cured product> The cured product of the present invention is a cured product obtained by curing the above-mentioned curable composition. The cured product of the present invention is obtained by curing the curable composition of the present invention by irradiating it with active energy rays such as ultraviolet light. Examples of active energy rays include ultraviolet light, electron beams, X-rays, infrared light, and visible light.

[0113] In one embodiment, when curing a curable composition by ultraviolet irradiation, various ultraviolet irradiation devices can be used. As the light source for the ultraviolet irradiation device, xenon lamps, high-pressure mercury lamps, metal halide lamps, LED-UV lamps, etc., can be used. The ultraviolet irradiation dose is typically 10 to 10,000 mJ / cm². 2 The values ​​are 100-5000 mJ / cm². 2 Preferably, 150-3000 mJ / cm² 2 This is preferable.

[0114] In one embodiment, when curing a curable composition by electron beam irradiation, various electron beam irradiation devices can be used. The electron beam irradiation dose is usually 0.5 to 20 Mrad, and preferably 1 to 15 Mrad.

[0115] In one embodiment, the temperature at which the curable composition is cured (the temperature at which the active energy rays are irradiated) can be set appropriately considering the heat resistance and thermal deformation properties of the substrate. For example, 20 to 200°C is preferred, and 60 to 150°C is more preferred. The curing time is, for example, 30 seconds to 1 hour, and 1 minute to 15 minutes is more preferred.

[0116] If the curable composition contains an organic solvent, the organic solvent may be evaporated by drying the curable composition before irradiation with active energy rays. The drying temperature should be set appropriately considering the heat resistance and heat deformation properties of the substrate, the boiling point of the organic solvent, etc. For example, 20 to 200°C is preferred, and 60 to 150°C is more preferred. The drying time is, for example, 1 minute to 1 hour is preferred, and 2 minutes to 15 minutes is more preferred.

[0117] <Laminate> The laminate of the present invention comprises a substrate and a layer made of the cured product of the present invention (hereinafter also referred to as the "cured product layer"). The cured product layer is laminated or composited with the substrate. In one embodiment, the cured product layer may be provided on a part of the surface of the substrate or on the entire surface.

[0118] (base material) The shape of the substrate is not particularly limited. For example, it may be in the form of a film, a plate, or a geometric shape, and any of these shapes is acceptable. As for the material of the base material, for example, Metals such as galvanized steel, zinc alloy plated steel, stainless steel, and tin-plated steel; Plastics such as polymethyl methacrylate resin, polycarbonate resin, polyester resin, polystyrene resin, ABS resin, AS resin, polyamide resin, polyarylate resin, polymethacrylimide resin, and polyaryldiglycol carbonate resin; These are some examples. These base materials may be metal or plastic, either used individually or in combination of two or more types.

[0119] As a substrate, a plastic substrate is preferred due to the significant benefits (such as improved weather resistance) that can be obtained by providing a cured layer. Examples of plastic substrates include plastic substrates containing at least one selected from the group consisting of polymethyl methacrylate resin, polycarbonate resin, polystyrene resin, and polymethacrylimide resin. Among these, polymethyl methacrylate resin and polycarbonate resin are preferred from the viewpoint of transparency and ease of molding. Furthermore, polycarbonate resin is more preferred from the viewpoint of heat resistance and impact resistance.

[0120] The thickness of the cured layer is preferably 3 to 50 μm from the viewpoint of weather resistance and crack reduction. The thickness of the cured layer can be adjusted by the thickness of the coating film of the curable composition applied to the substrate.

[0121] In one embodiment, the laminate may have multiple substrates. In another embodiment, the laminate may have multiple cured material layers. For example, multiple types of cured material layers may be laminated onto a substrate. Alternatively, multiple substrates and multiple cured material layers may be laminated together. If the substrate is in the form of a film or a plate, the cured material layer may be laminated on one surface of the substrate, or on both surfaces of the substrate.

[0122] The laminate can be manufactured by coating the surface of a substrate with a curable composition, and then curing the curable composition to produce a cured product. In one embodiment, the laminate can be manufactured, for example, by coating a substrate with the curable composition of the present invention to form a coating film, and then curing the coating film by irradiating it with active energy rays.

[0123] The painting method is not particularly limited. Various methods can be used. For example, brush painting, bar coating, spray coating, dip coating, spin coating, curtain coating, etc. are examples, but are not limited to these. Since the curable composition of the present invention tends to have a viscosity suitable for spray coating, spray coating is preferred as the coating method. The coating film can be cured in the same manner as the curable composition described above. [Examples]

[0124] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following description. In the examples, "parts" refers to "parts by mass".

[0125] <Ingredients and abbreviations> The raw materials used and their abbreviations are as follows:

[0126] (Compound A) • CP-EA: Caprolactone-modified (1 mol) ethyl acrylate ((TI)2: 5.44, Mw: 214.3). BCA: Butylcarbitol acetate ((TI)2: 5.59, Mw: 204.3). MTG-A: Methoxytriethylene glycol acrylate ((TI)2: 5.86, Mw: 218.2). BTG-A: Butoxy-triethylene glycol acrylate ((TI)2: 7.14, Mw: 260.3). ABEC: 4-Acryloyloxybutylethyl carbonate ((TI)2: 5.14, Mw: 216.2). ABBC: 4-Acryloyloxybutylbutyl carbonate ((TI)2: 6.09, Mw: 244.3). C4DA: 1,4-butanediol diacrylate ((TI)2: 5.15, Mw: 198.2). C6DA: 1,6-Hexanediol diacrylate ((TI)2: 6.07, Mw: 226.3). C9DA: 1,9-nonanediol diacrylate ((TI)2: 7.40, Mw: 268.3). DCPDA: Tricyclodecanedimethanol diacrylate ((TI)2:3.98, Mw:304.4).

[0127] (Compound B) • TMPTA: Trimethylolpropane triacrylate (product name Viscoat #295, manufactured by Osaka Organic Chemical Industry Co., Ltd.). • M-315: A mixture of isocyanuric acid EO-modified diacrylate and isocyanuric acid EO-modified triacrylate (product name: Aronics M-315, manufactured by Toagosei Co., Ltd.). • DPCA-20: Dipentaerythritol / caprolactone acrylic acid ester (product name KAYARAD DPCA-20, manufactured by Nippon Kayaku Co., Ltd.).

[0128] (Compound B-1) CN2303: Acrylate with a hyperbranch structure (manufactured by Sartomer), number of (meth)acryloyl functional groups: 6, viscosity (25℃): 375 mPa·s. CN2304: Acrylate with a hyperbranch structure (manufactured by Sartomer), number of (meth)acryloyl functional groups: 18, viscosity (25℃): 750 mPa·s.

[0129] (Compound C) • C1-1: A polyfunctional urethane acrylate having acryloyl groups obtained in Synthesis Example 1 below, with 2 (meth)acryloyl functional groups and a mass-average molecular weight (Mw) of 4100. • C1-2: A polyfunctional urethane acrylate having acryloyl groups, obtained in Synthesis Example 2 below, with 2 (meth)acryloyl functional groups and a mass-average molecular weight (Mw) of 3600.

[0130] (Synthesis Example 1: Synthesis of C1-1) A flask equipped with a dropping funnel with a heat retention function, a reflux condenser, a stirrer, and a thermometer was charged with 530 parts of dicyclohexylmethane diisocyanate and 300 ppm of di-n-butyltin dilaurate, and heated to 50°C. Then, 700 parts (1 mol) of Kuraray Polyol C-770, a polycarbonate diol manufactured by Kuraray Co., Ltd., was added dropwise over 2 hours. After stirring at 50°C for 2 hours, the temperature was raised to 70°C over 1 hour. Then, 239 parts of 2-hydroxyethyl acrylate were added dropwise over 2 hours, and the mixture was stirred for a further 2 hours to obtain urethane acrylate C1-1.

[0131] (Synthesis Example 2: Synthesis of C1-2) A flask equipped with a stirrer, reflux condenser, dropping funnel, and thermometer was charged with 530 parts dicyclohexylmethane diisocyanate and 300 ppm di-n-butyltin dilaurate, and heated to 50°C. Subsequently, 441 parts of PTG-850SN manufactured by Hodogaya Chemical Co., Ltd. and 69 parts of 4-hydroxy-N-(2-hydroxyethyl)-N-methylbutanamide were added dropwise over 2 hours as polyol compounds. After stirring at 50°C for 2 hours, the temperature was raised to 70°C over 1 hour. Then, 262 parts of 2-hydroxyethyl acrylate were added dropwise over 2 hours, and the mixture was stirred for a further 2 hours to obtain urethane acrylate C1-2.

[0132] (Other monomers) • 4-HBA: 4-hydroxybutyl acrylate ((TI)2: 3.64, Mw: 144.2). ISTA: Isostearyl acrylate ((TI)2: 9.18, Mw: 324.5). • CTFA: Cyclic trimethylolpropane formal acrylate ((TI)2:2.98, Mw:200.2) • UM-90DA: Polycarbonate diol diacrylate (manufactured by Ube Industries, Ltd., (TI)2: 13.70, Mw: 736.9) • 2-EHA: 2-ethylhexyl acrylate ((TI)2: 3.56, Mw: 184.3).

[0133] (Other ingredients) • Chinuvin 400 (UV absorber): A mixture of 2-[4-[(2-hydroxy-3-dodecyloxypropyl)oxy]-2-hydroxyphenyl]-4,6-bis-(2,4-dimethylphenyl)-1,3,5-triazine and 2-[4-[(2-hydroxy-3-tridecyloxypropyl)oxy]-2-hydroxyphenyl]-4,6-bis-(2,4-dimethylphenyl)-1,3,5-triazine and 1-methoxy-2-propanol (manufactured by BASF). • Chinuvin 405 (UV absorber): 2-[4-[(2-hydroxy-3-(2'-ethyl)hexyl)oxy]-2-hydroxyphenyl]-4,6-bis-(2,4-dimethylphenyl)-1,3,5-triazine (manufactured by BASF). • Chinuvin 479 (UV absorber): Structure not disclosed (manufactured by BASF). Omnirad TPO (photopolymerization initiator): 2,4,6-trimethylbenzoyldiphenylphosphine oxide. • Omnirad 184 (photopolymerization initiator): 1-hydroxycyclohexyl phenyl ketone.

[0134] (others) • Tinuvin 123 (light stabilizer): Bis(2,2,6,6-tetramethyl-1-(octyloxy)-4-piperidinyl) ester decandioate, reaction product of 1,1-dimethylethyl hydroperoxide and octane (manufactured by BASF). • BYK-333 (silicone-based leveling agent): Polyether-modified polydimethylsiloxane (manufactured by BYK).

[0135] PGM (organic solvent): Propylene glycol monomethyl ether.

[0136] <Measurement method> The method for evaluating physical properties is as follows: (TI)2: The second Mohal index was calculated by determining the Laplacian matrix when each compound is described using graph theory, and then calculating the second smallest eigenvalue of the Laplacian matrix, χ², using a calculation site (https: / / keisan.casio.jp / exec / system / 1505174268) or spreadsheet software. Subsequently, (TI)2: the second Mohal index was obtained from the following equation (L). (TI)² = 4 / (N × χ²) ... Equation (L) In formula (L), N is the number of atoms in the compound's skeleton.

[0137] (Viscosity of compound B-1 (25°C)) The viscosity of compound B-1 (at 25°C) was measured using an E-type viscometer TVE-20H (manufactured by Toki Sangyo Co., Ltd.).

[0138] (Viscosity of curable composition (25°C)) After diluting the curable composition with PGM so that its solid content concentration matched the concentrations shown in Table 3, the viscosity (at 25°C) was measured using an E-type viscometer TVE-20H (manufactured by Toki Sangyo Co., Ltd.).

[0139] (Mass average molecular weight (Mw)) The mass-average molecular weight (Mw) of a polymer (compound C, etc.) is the molecular weight on a standard polystyrene basis, measured by gel permeation chromatography (GPC) under the following conditions. Equipment: Tosoh Corporation high-speed GPC system HLC-8320GPC model UV (ultraviolet) detector: Tosoh Corporation UV-8320 model Flow rate: 0.35mL / min Inlet temperature: 40℃ Oven temperature: 40℃ RI (Differential Refractometer) Temperature: 40℃ UV wavelength: 254nm Sample injection volume: 10 μL Columns: Three columns were concatenated in the following order: (1), (2), and (3). (1) TSKgel superHZM-M (4.6mm ID x 15cm L) manufactured by Tosoh Corporation (2) TSKgel superHZM-M (4.6mm ID x 15cm L) manufactured by Tosoh Corporation (3) TSKgel HZ2000 manufactured by Tosoh Corporation (4.6mm ID x 15cm L) Guard column: TSKguardcolumn SuperHZ-L (4.6mm ID x 3.5cm L) manufactured by Tosoh Corporation Solvent: THF (with BHT stabilizer) The sample concentration was adjusted so that the resin content was 0.2% by mass.

[0140] <Evaluation Method> (Creation of evaluation samples) A polycarbonate resin injection-molded sheet (Panlight L-1225Z-100 (product name), manufactured by Teijin Limited, 3 mm thick) was coated with a curable composition using spray or a bar coater (#14). The sheet was heated and dried in an IR (far-infrared) drying oven at 70°C for 240 seconds to form a coating. Next, the formed coating was subjected to irradiation using a high-pressure mercury lamp under an air atmosphere, with an ultraviolet light meter UV-351 manufactured by Oak Manufacturing Co., Ltd., at a dose of 2000 mJ / cm². 2 The coating film was cured by irradiating it with ultraviolet light at a wavelength of 340-380 nm, forming a cured layer. The thickness of the cured layer was 9 μm. This resulted in a laminate having a polycarbonate resin injection molded sheet and a cured layer. The obtained laminate was used as an evaluation sample for the following evaluation.

[0141] (Hot water resistance and adhesion) Using a constant temperature water bath, the evaluation samples were immersed in 80°C hot water, and the changes in the appearance of the evaluation samples after 8 hours were visually confirmed. Subsequently, cross-cuts reaching the substrate were made in the cured coating film on the sample at 1 mm intervals. 2 100 grid patterns were created. Cellophane tape (manufactured by Nichiban Co., Ltd., product name: Cellotape) was applied to the surface of the hardened coating film with cross-cuts and then rapidly peeled off. The number of grid patterns that peeled off was counted. The criteria for judging hot water adhesion resistance are as follows: • Judgment criteria (board pattern adhesion test) 5B (Best): No peeling. 4B (Good): Fine peeling is visible in the cut areas, but there is no peeling in the grid. 3B (Acceptable): Less than half of the grid lines peel off. 2B (Defective): More than half of the grid lines are peeled off. 1B (Not acceptable): The paint film in the grid will peel off completely.

[0142] (Heat and moisture resistance and adhesion) Using a constant temperature and humidity chamber, evaluation samples were placed in an environment of 70°C and 95%RH, and the changes in the appearance of the evaluation samples were visually observed after 240 hours. Moisture and heat resistance were evaluated using the same method as for hot water resistance. The criteria for determining moisture and heat resistance are as follows: • Judgment criteria (board pattern adhesion test) 5B (Best): No peeling. 4B (Good): Fine peeling is visible in the cut areas, but there is no peeling in the grid. 3B (Acceptable): Less than half of the grid lines peel off. 2B (Defective): More than half of the grid lines are peeled off. 1B (Not acceptable): The paint film in the grid will peel off completely.

[0143] (Pencil hardness) Pencil hardness was evaluated according to JIS K5600-5-4. Pencils of various hardness levels were applied to the surface of the evaluation sample at a 45° angle, and a scratch test was performed by applying a load. The hardness of the hardest pencil that did not scratch the surface was defined as the pencil hardness.

[0144] (Spray-coatable) The appearance of the evaluation samples was visually inspected, and the spray coating properties were evaluated at 25°C and 50% RH. The criteria for judging spray coating properties are as follows: ·Judgment criteria A (Good): The surface of the evaluation sample is free from wrinkles and whitening. B (Acceptable): Wrinkles or whitened areas are observed on the surface of the evaluation sample. C (Not possible): The viscosity of the curing composition was too high for spray painting, so bar coating was performed.

[0145] <Example 1> 6.0 parts of CP-EA, 1.0 part of 2-EHA, 10.0 parts of DPCA-20, 6.0 parts of CN2304, 4.0 parts of C1-1, 3.0 parts of C1-2, 3.0 parts of Chinubin 400, 0.5 parts of Chinubin 479, 1.6 parts of Omnirad TPO, 1.6 parts of Omnirad 184, 0.3 parts of Chinubin 123, and 0.04 parts of BYK-333 were uniformly mixed. Then, using PGM as a diluent, the mixture was diluted to obtain a curable composition with a solid content concentration as shown in Table 3. Evaluation samples were prepared using the obtained curable composition. The evaluation results for the obtained curable composition and evaluation samples are shown in Table 3.

[0146] <Examples 2-12, Comparative Examples 1-5> Except for the composition of the curable composition being as shown in Tables 1 and 2, the curable composition was prepared using the same method as in Example 1, and evaluation samples were also prepared. The evaluation results of the obtained curable composition and evaluation samples are shown in Table 3. The numerical values ​​of the composition of the curable composition shown in Tables 1 and 2 are expressed in grams (g).

[0147] [Table 1]

[0148] [Table 2]

[0149] [Table 3]

[0150] As shown in Table 3, in Examples 1 to 12, cured coating films with excellent hot water adhesion were obtained. Furthermore, the curable compositions of Examples 1 to 12 had practically sufficient spray coating properties. In addition, in Examples 1 to 8, cured coating films with excellent heat and moisture adhesion in addition to hot water adhesion were obtained. On the other hand, in the compositions of Comparative Examples 1 to 4, which did not contain compound A, and in the composition of Comparative Example 5, which did not contain compound B, the cured coating film showed poor resistance to hot water adhesion and poor resistance to humid heat adhesion. Furthermore, in the composition of Comparative Example 5, which did not contain compound B, the cured coating film showed poor pencil hardness. [Industrial applicability]

[0151] According to the curable composition of the present invention, a coating film with excellent hot water adhesion can be obtained. The cured product of this invention exhibits excellent resistance to hot water adhesion. The laminate of the present invention has a layer made of a cured material that has excellent resistance to hot water adhesion. According to the method for producing the curable composition of the present invention, a curable composition with excellent hot water adhesion when used as a coating film can be obtained. According to the method for producing a cured product of the present invention, a cured product with excellent resistance to hot water adhesion can be obtained. According to the method for manufacturing a laminate of the present invention, a laminate having a layer made of a cured material with excellent hot water adhesion properties can be obtained.

Claims

1. A curable composition containing compound A and compound B. Compound A: A compound whose second Mohal index, calculated using the following formula (L), is between 3.65 and 9.17 (excluding compound B below). Compound B: A polyfunctional (meth)acrylate monomer having three or more (meth)acryloyl groups. (TI) ２ = 4 / (N×χ ２ ) ... Formula (L) In formula (L), (TI) ２ This is the second Mohal index; N is the number of atoms in the skeleton of compound A, excluding the hydrogen atoms; χ ２ is the second smallest eigenvalue of the Laplacian matrix representing the molecular structure of compound A; The Laplacian matrix is ​​an N x N square matrix; The value of the k-th diagonal element (k,k) from the left of the Laplacian matrix is ​​the k-th atom Z of the skeleton of compound A, excluding the hydrogen atoms. ｋ This is the number of atoms remaining after removing hydrogen atoms from the atoms bonded to it; Among the components (i, j) in the i-th row and j-th column of the off-diagonal components of the Laplacian matrix, the value in each column of the component (k, j) in the k-th row is the j-th atom Z excluding hydrogen atoms in the skeleton of Compound A ｊ is the aforementioned atom Z ｋ is -1 when bonded to, and the aforementioned atom Z ｊ is the aforementioned atom Z ｋ is 0 when not bonded to; The sum of the elements in each row and each column of the Laplacian matrix is ​​zero; N is an integer greater than or equal to 2; i, j, and k are integers between 1 and N; i and j are different from each other.

2. The curable composition according to claim 1, further comprising the compound B-1 described below. Compound B-1: A (meth)acrylate having at least one selected from the group consisting of a dendrimer structure and a hyperbranched structure (excluding compound B).

3. The curable composition according to claim 1, wherein the viscosity of the curable composition at 25°C is 250 mPa·s or less.

4. A cured product of a curable composition according to any one of claims 1 to 3.

5. A laminate comprising a base material and a layer made of the cured product described in claim 4.

6. The laminate according to claim 5, wherein the substrate is a plastic substrate.

7. A method for producing a curable composition, comprising mixing compound A (excluding compound B below), which is selected as a compound whose second Mohal index calculated by the following formula (L) is between 3.65 and 9.17, with compound B below. Compound B: A polyfunctional (meth)acrylate monomer having three or more (meth)acryloyl groups. (TI) ２ = 4 / (N×χ ２ ) ... Formula (L) In formula (L), (TI) ２ This is the second Mohal index; N is the number of atoms in the skeleton of compound A, excluding the hydrogen atoms; χ ２ is the second smallest eigenvalue of the Laplacian matrix representing the molecular structure of compound A; The Laplacian matrix is ​​an N x N square matrix; The value of the k-th diagonal element (k,k) from the left of the Laplacian matrix is ​​the k-th atom Z of the skeleton of compound A, excluding the hydrogen atoms. ｋ This is the number of atoms remaining after removing hydrogen atoms from the atoms bonded to it; Of the i-th row, j-th column components (i, j) of the off-diagonal elements of the Laplacian matrix, the values ​​in each column of the k-th row component (k, j) are the j-th atom Z of the skeleton of compound A, excluding the hydrogen atoms. ｊ is the atom Z ｋ When bonded with the atom Z, it is -1, and the atom Z ｊ is the atom Z ｋ It is 0 when not bound to; The sum of the elements in each row and each column of the Laplacian matrix is ​​zero; N is an integer greater than or equal to 2; i, j, and k are integers between 1 and N; i and j are different from each other.

8. Furthermore, the manufacturing method according to claim 7, wherein the following compound B-1 is mixed in. Compound B-1: A (meth)acrylate having at least one selected from the group consisting of a dendrimer structure and a hyperbranched structure (excluding compound B).

9. A method for producing a cured product, comprising curing a curable composition obtained by the manufacturing method described in claim 7 or claim 8.

10. A method for manufacturing a laminate having a base material and a layer made of a cured product, A method for manufacturing a laminate, comprising curing a curable composition obtained by the manufacturing method described in claim 7 or claim 8 to obtain the cured product.

11. The manufacturing method according to claim 10, wherein the substrate is a plastic substrate.

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