Material for laser welding

Abstract

The present invention is a material for laser welding, which contains a resin and a cyanine compound represented by formula (1), and which is characterized in that the cyanine compound has an average transmittance of 81% or more in the wavelength range of 380 nm to 780 nm when the transmittance of the maximum absorption wavelength is 10% in the wavelength range of 300 nm to 1300 nm. [In formula (1), L represents a methine chain having 3-9 carbon atoms, methine groups contained in the methine chain each independently have a substituent, the substituents can be connected to each other, A + and A represent groups bonded to methine chain L, and X-represents a monovalent anion having a conjugated acid pKa of-8.0 or less]

Description

Technical Field

[0001] This invention relates to a laser welding material, specifically a laser welding material containing resin and anthocyanin compound. Furthermore, this invention also provides a laminate having a light-absorbing layer formed from the laser welding material of this invention, and an absorbing material formed from the laser welding material of this invention. Background Technology

[0002] Laser welding is a joining method that uses laser light to fuse components together. Laser welding typically involves overlapping a transmitting material that transmits laser light with an absorbing material that absorbs it, and then irradiating the transmitting material with laser light to join the transmitting and absorbing materials. As the absorbing material, a resin containing a coloring pigment such as carbon black or black dye is used. By using this absorbing material, the laser energy can be efficiently absorbed, thus enabling proper laser welding. However, in this case, the transmitting and absorbing materials are different colors, so the joint between them becomes noticeable, potentially limiting the applicability of the welded body. To address this, Patent Document 1 discloses a laser welding material containing a specific squarylium compound as a pigment for absorbing laser light. According to the laser welding material in Patent Document 1, transparent resins can be laser-fused together, exhibiting high invisibility and making the laser-welded joint inconspicuous.

[0003] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2019-11455 Summary of the Invention The problem the invention aims to solve Ideally, laser welding materials possess high visible light transmittance of pigments that absorb laser light. This allows for easy matching of the laser welding material's color to the components to be joined, or the creation of any color, resulting in a wide range of applications. The present invention was made in view of this situation, and its object is to provide a laser welding material that is suitable for laser welding and possesses high visible light transmittance of pigments that absorb laser light. Furthermore, the present invention also provides a laminate having a light-absorbing layer formed from the laser welding material of the present invention, and an absorbing material formed from the laser welding material of the present invention.

[0004] Solution for solving the problem The laser welding material, laminate, and absorbing material of the present invention, which can solve the aforementioned problems, are described below.

[0005] [1] A laser welding material comprising a resin and anthocyanin compound represented by formula (1) below, wherein, [Chemical Formula 1]

[0006] In formula (1), L represents a methine chain with 3 to 9 carbon atoms, wherein each methine group in the chain may independently have substituents, and these substituents may be linked together. A + And A represents the group bonded to the L of the methine chain. X - [This refers to monovalent anions with a pKa below -8.0, representing conjugate acids] The anthocyanin compound has an average transmittance of over 81% in the wavelength range of 380nm to 780nm, with a transmittance of 10% at the wavelength of maximum absorption.

[0007] [2] According to the laser welding material described in [1], the cyanin compound has a maximum absorption wavelength in the wavelength range of 750 nm to 1300 nm.

[0008] [3] The laser welding material according to [1] or [2] further contains a solvent.

[0009] [4] The material for laser welding according to any one of [1] to [3], wherein the resin is a thermoplastic resin.

[0010] [5] The laser welding material according to any one of [1] to [4], wherein the resin is a (meth)acrylic resin comprising a structural unit having a ring structure in the main chain, wherein the ring structure comprises at least one selected from the group consisting of a lactone ring structure, a glutarimide structure and a maleimide structure.

[0011] [6] The laser welding material according to any one of [1] to [5], wherein in formula (1), A + A represents any one of the groups shown in equations (2) to (7) below.

[0012] [Chemical Formula 2]

[0013] In equation (2), R 11 R represents an organic group. 12 ~R 17 Each of these elements independently represents a hydrogen atom, a halogen atom, or an organic group; * indicates a bonding site with the methylene chain L of formula (1). [Chemical Formula 3]

[0014] In equation (3), R 21The symbol represents an organic group, ring S represents a hydrocarbon ring with a fused ring structure that can be substituted or a heterocycle with a fused ring structure that can be substituted, and is spirobonded to an adjacent pyrrole ring, ring T represents a fused ring of a substitutable aromatic hydrocarbon ring, a fused ring of a substitutable aromatic heterocycle, or a fused ring containing such ring structures, and * represents a bonding site with the methylene chain L of formula (1). [Chemical Formula 4]

[0015] In equation (4), R 31 R represents an organic group. 32 ~R 35 Each can independently represent a hydrogen atom, a halogen atom, or an organic group, or R 32 With R 33 R 33 With R 34 R 34 With R 35 They can be connected to form a ring, Y 1 Represents oxygen atom, sulfur atom, CH=CH or CR 36 R 37 R 36 and R 37 Each represents an organic group, and * indicates a bonding site with the methylene chain L of formula (1). [Chemical Formula 5]

[0016] In equation (5), R 41 ~R 44 Each can independently represent a hydrogen atom, a halogen atom, or an organic group, or R 41 With R 42 R 43 With R 44 They can be connected to form a ring, Y 2 Represents oxygen atom, sulfur atom, or NR. 45 R 45 [This indicates an organic group, and * indicates a bonding site with the methylene chain L of formula (1)] [Chemical Formula 6]

[0017] In equation (6), R 51 ~R 54 Each can independently represent a hydrogen atom, a halogen atom, or an organic group, Y 3 Represents oxygen atom, sulfur atom, or NR. 55 R 55 [This indicates an organic group, and * indicates a bonding site with the methylene chain L of formula (1)] [Chemical Formula 7]

[0018] In equation (7), R 61 ~R 63 R 65 ~R 67 Each can independently represent a hydrogen atom, a halogen atom, or an organic group, R 64 [This indicates an organic group, and * indicates a bonding site with the methylene chain L of formula (1)] [7] A laminate comprising: a substrate; and a light-absorbing layer disposed on the substrate, formed of a laser welding material as described in any one of [1] to [6].

[0019] [8] According to the laminate described in [7], the average transmittance of the light-absorbing layer in the wavelength range of 380 nm to 780 nm is 80% or more.

[0020] [9] An absorbing material formed from any one of [1] to [6] for laser welding.

[0021] Invention Effects The laser welding material of the present invention can be used to properly weld components together by irradiating them with a laser. In addition, the anthocyanin compound contained therein has high visible light transmittance, so it can easily form any color and has a wide range of applications. Attached Figure Description

[0022] Figure 1 The transmission spectra of the light-absorbing layers of the resin substrates B1 to B4 prepared in the examples are shown.

[0023] Figure 2 The transmission spectra of the light-absorbing layers of the resin substrates B5 and B6 prepared in the embodiments are shown.

[0024] Figure 3 The transmission spectra of the light-absorbing layers of the resin substrates B7 to B9 prepared in the examples are shown.

[0025] Figure 4 The transmission spectrum of the light-absorbing layer of the resin substrate B10 prepared in the embodiment is shown.

[0026] Figure 5 The transmission spectrum of the light-absorbing layer of the resin substrate B11 prepared in the embodiment is shown.

[0027] Figure 6 The transmission spectrum of the resin substrate D1 prepared in the embodiment is shown.

[0028] Figure 7 The transmission spectra of resin substrates D2 and D3 prepared in the examples are shown.

[0029] Figure 8 The transmission spectrum of the resin substrate D4 prepared in the embodiment is shown.

[0030] Figure 9 The transmission spectrum of the resin substrate D5 prepared in the embodiment is shown.

[0031] Figure 10 The transmission spectrum of the resin substrate D6 prepared in the embodiment is shown.

[0032] Figure 11 The transmission spectrum of the pigment component of the resin substrate D1 prepared in the embodiment is shown.

[0033] Figure 12 The transmission spectra of the pigment components in the resin substrates D2 and D3 prepared in the examples are shown.

[0034] Figure 13 The transmission spectrum of the pigment component of the resin substrate D4 prepared in the embodiment is shown.

[0035] Figure 14 The transmission spectrum of the pigment component of the resin substrate D5 prepared in the embodiment is shown.

[0036] Figure 15 The transmission spectrum of the pigment component of the resin substrate D6 prepared in the embodiment is shown. Detailed Implementation

[0037] This invention relates to a laser welding material containing resin and anthocyanin compound. The laser welding material is used to weld components together by irradiation with a laser. The material absorbs the laser light and generates heat, thereby enabling the components to be welded together.

[0038] The laser welding material of the present invention uses anthocyanin compounds as pigments that absorb laser light. In laser welding, for example, lasers with wavelengths of 800 nm to 1300 nm are used, and the anthocyanin compounds can appropriately absorb light in this wavelength range, functioning as a heat source. On the other hand, anthocyanin compounds have high transmittance in the visible light range and excellent invisibility. Therefore, the laser welding material of the present invention can be a material that is substantially free of coloring from anthocyanin compounds, easily making the color of the laser welding material consistent with the transmitting material, or forming any color, thus having a wide range of applications. The laser welding material of the present invention can be used to form an absorbing material that absorbs laser light, or to form a light-absorbing layer disposed between laser-welded components to bond these components together. In the latter case, at least one of the laser-welded components is a transmitting material that transmits laser light. The laser welding material of the present invention will be described in detail below.

[0039] The laser welding material of the present invention contains a resin and anthocyanin compound represented by the following formula (1). In formula (1), L represents a methine chain with 3 or more and 9 or fewer carbon atoms, wherein each methine group in the methine chain may independently have a substituent, and the substituents may be interconnected, A + And A represents the group bonded to the L-chain of the methine group, X - The conjugate acid is a monovalent anion with a pKa below -8.0. The anthocyanin compounds in formula (1) also include compounds in resonance relationships.

[0040] [Chemical Formula 8]

[0041] In formula (1), L represents a methine chain with 3 or more but less than 9 carbon atoms, that is, a methine chain with 3 or more but less than 9 methine atoms (-CH=) linked together by conjugated double bonds. Each methine atom in the methine chain (i.e., the hydrogen atom on the methine atom) may have a substituent independently, and these substituents may be linked together. Substituents that the methine atom may have (hereinafter sometimes referred to as "substituent P") include halogen groups (halogen atoms) or organic groups. It should be noted that when the methine atom in the methine chain has a substituent, the number of carbon atoms in the methine chain refers to the number of carbon atoms excluding the substituents.

[0042] The methine chain L is preferably formed by an odd number of methine groups linked together. Therefore, the number of carbon atoms in the methine chain is preferably 3, 5, 7, or 9, and it is preferably formed by 3, 5, 7, or 9 methine groups linked together. In this case, the methine compound represented by formula (1) is represented by the following formulas (1A) to (1D). In formulas (1A) to (1D), R 71 ~R 79 Each can be used independently to represent a hydrogen atom, a halogen atom, or an organic group.

[0043] [Chemical Formula 9]

[0044] Organic groups that can be substituents P as methines include, for example: alkyl, alkoxy, alkylthio, alkoxycarbonyl, alkylsulfonyl, alkylsulfinyl, aryl, aralkyl, aryloxy, arylthio, aryloxycarbonyl, arylsulfonyl, arylsulfinyl, heteroaryl, amino, amide, sulfonamide, carboxyl (carboxylic acid), cyano, etc.

[0045] Alkyl groups that can be substituted with P include: methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecanyl, octadecyl, nonadecanyl, eicosyl, and other straight-chain or branched alkyl groups; cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, and other cycloalkyl groups. Alkyl groups may have substituents, including: aryl, heteroaryl, halogenated, hydroxyl, carboxyl, alkoxy, cyano, nitro, amino, sulfonyl, etc. Alkyl groups with halogenated groups include: monohalogenated alkyl groups, dihalogenated alkyl groups, alkyl groups with trihalomethyl units, and perhalogenated alkyl groups. Fluorine, chlorine, and bromine atoms are preferred as halogenated groups, with fluorine atoms being particularly preferred. The number of carbon atoms (excluding the number of carbon atoms of the substituent) of the alkyl group is preferably 1 to 20. Specifically, if it is a straight-chain or branched alkyl group, the number of carbon atoms is preferably 1 to 20, more preferably 1 to 10, and even more preferably 1 to 5. If it is a cyclic alkyl group, the number of carbon atoms is preferably 4 to 10, more preferably 5 to 8.

[0046] For specific examples of alkyl groups contained in alkoxy, alkathio, alkoxycarbonyl, alkylsulfonyl, and alkylsulfinyl groups of substituent P, please refer to the above description of alkyl groups.

[0047] Examples of aryl groups that can be substituted with P include: phenyl, biphenyl, naphthyl, anthraceneyl, phenanthryl, pyrene, indene, etc. The aryl group may have substituents, including: alkyl, alkoxy, heteroaryl, halogroup, haloalkyl, hydroxyl, cyano, nitro, amino, thiocyanate, acyl, alkoxycarbonyl, aryloxycarbonyl, carbamoyl, sulfonyl, alkylsulfinyl, arylsulfinyl, alkylsulfonyl, arylsulfonyl, aminosulfonyl, etc. The number of carbon atoms in the aryl group (excluding the substituents) is preferably 6 to 20, more preferably 6 to 12.

[0048] Examples of aralkyl groups that can be substituted with P include benzyl, phenethyl, phenylpropyl, phenylbutyl, phenylpentyl, and naphthylmethyl. Aralkyl groups may have substituents, including alkyl, alkoxy, halogroup, haloalkyl, cyano, nitro, thiocyanate, acyl, alkoxycarbonyl, aryloxycarbonyl, carbamoyl, sulfonyl, alkylsulfinyl, arylsulfinyl, alkylsulfonyl, arylsulfonyl, and aminosulfonyl. The number of carbon atoms in the aralkyl group (excluding the substituents) is preferably 7 to 25, more preferably 7 to 15.

[0049] For specific examples of aryl groups contained in aryloxy, arylthio, aryloxycarbonyl, arylsulfonyl, and arylsulfinyl groups of substituent P, please refer to the above description of aryl groups.

[0050] Examples of heteroaryl groups that can be represented by substituent P include: thienyl, thiaranyl, isothiobenzopyranyl, pyrrolithyl, imidazolyl, pyrazolyl, pyridyl, pyridine, pyrrolithyl, pyrimidinyl, pyridazinyl, thiazolyl, isothiazolyl, furanyl, and pyranyl. The heteroaryl group may have substituents, including: alkyl, alkoxy, aryl, haloyl, haloalkyl, hydroxyl, cyano, amino, nitro, thiocyanate, acyl, alkoxycarbonyl, aryloxycarbonyl, carbamoyl, sulfonyl, alkylsulfinyl, arylsulfonyl, alkylsulfonyl, arylsulfonyl, and aminosulfonyl. The number of carbon atoms in the heteroaryl group (excluding the substituents) is preferably 2 to 20, more preferably 3 to 15.

[0051] Amino groups that are substituents of P can be listed as having the formula: -NR a1 R a2 The amino group represents R, where R a1 and R a2 Each can be independently a hydrogen atom, alkyl, alkenyl, alkynyl, aryl, aralkyl, heteroaryl, etc. Specific examples of alkyl, aryl, aralkyl, and heteroaryl groups are given in the description of these groups above. As for alkenyl and alkynyl groups, examples can be listed where some of the carbon-carbon single bonds of the alkyl groups exemplified above are replaced by double or triple bonds. R a1 With R a2 They can be connected to form a ring. R a1 With R a2 The ring formed by the connection is preferably 5 or 6 ring elements, and the constituent atoms of the ring are preferably carbon atoms, oxygen atoms, and sulfur atoms, in addition to nitrogen atoms.

[0052] Amide groups that are substituents P can be listed as having the formula: -NH-C(=O)-R a3 The amide group represents, where R a3 These can be alkyl, aryl, aralkyl, heteroaryl, etc. Specific examples of alkyl, aryl, aralkyl, and heteroaryl groups can be found in the descriptions of these groups above.

[0053] The sulfonamide group that serves as the substituent P can be represented by the formula: -NH-SO2-R a4 The sulfonamide group represents R. a4 These can be alkyl, aryl, aralkyl, heteroaryl, etc. Specific examples of alkyl, aryl, aralkyl, and heteroaryl groups can be found in the descriptions of these groups above.

[0054] The substituent P is preferably a halogroup, alkyl group, alkoxy group, aryl group, aralkyl group, or amino group, more preferably a halogroup, alkyl group, aryl group, or amino group. In this case, the alkyl or alkoxy group preferably has 1 to 8 carbon atoms, more preferably 1 to 5, and even more preferably 1 to 3; the aryl group preferably has 6 to 12 carbon atoms, more preferably 6 to 10; and the aralkyl group preferably has 7 to 13 carbon atoms, more preferably 7 to 11. The amino group is preferably of the formula: -NR a1 R a2 The amino group represents R, where R a1 and R a2 Each of the atoms is independently a hydrogen atom, an alkyl group, or an aryl group, wherein the alkyl group preferably has 1 to 5 carbon atoms, more preferably 1 to 3, and the aryl group preferably has 6 to 12 carbon atoms, more preferably 6 to 10.

[0055] When the substituents P in the methine group are interconnected, it is preferable that the substituents bonded to the second adjacent methine group are interconnected to form a ring. In formulas (1A) to (1D), R is preferred. 71 With R 73 R 72 With R 74 R 73 With R 75 R 74 With R 76 R 75 With R 77 R 76 With R 78 Or R 77 With R 79 They are interconnected to form a ring.

[0056] The ring formed by the interconnected substituents P of the methine group is preferably a 5- to 8-membered ring, more preferably a 5- to 7-membered ring, and even more preferably a 5- or 6-membered ring. The ring formed by the interconnected substituents P of the methine group shares a portion with the methine chain, but may or may not have unsaturated bonds in the portion shared with the methine chain. Preferably, the ring formed by the interconnected substituents P of the methine group does not have unsaturated bonds in the portion shared with the methine chain.

[0057] The ring formed by the interconnection of substituents P in the methine group may have substituents. Examples of such substituents include organic groups and polar functional groups. For details of the organic groups, refer to the description of the organic groups of substituent P above. Examples of polar functional groups include: halogen groups, hydroxyl groups, nitro groups, sulfonyl groups (sulfonic acid groups), etc., with halogen groups being preferred. Among these, the substituents in the ring formed by the interconnection of substituents P are preferably halogen groups, alkyl groups, alkoxy groups, aryl groups, and amino groups. In this case, the alkyl and alkoxy groups preferably have 1 to 5 carbon atoms, more preferably 1 to 3, and even more preferably 1 or 2; the aryl groups preferably have 6 to 12 carbon atoms.

[0058] The substituent P that the methine group may have is preferably bonded to the meso (central) methine group or its adjacent methine group; other methine groups preferably do not have substituents. In formula (1A), R 71 ~R 73 It can be a hydrogen atom, an organic group, or a polar functional group. In formula (1B), R 72 ~R 74 It can be a hydrogen atom, an organic group, or a polar functional group, R 71 and R 75 Preferably, it is a hydrogen atom. In formula (1C), R 73 ~R 75 It can be a hydrogen atom, an organic group, or a polar functional group, R 71 R 72 R 76 R 77 Preferably, it is a hydrogen atom. In formula (1D), R 74 ~R 76 It can be a hydrogen atom, an organic group, or a polar functional group, R 71 ~R 73 R 77 ~R 79 Preferably, the substituent forms a ring without being attached to the mesyl group, and the substituent forms a ring with the adjacent mesyl group at the mesyl group and is interconnected. Furthermore, the mesyl chain L preferably does not have any substituents.

[0059] In equation (1), A + And A represents the group bonded to the methine chain L. For the anthocyanin compound shown in formula (1), it is preferable that the π-electron system extends from the methine chain L to A. + and A,A + And A is preferably a group that forms this π-electron system. As A + And A, preferably the groups shown in the following formulas (2) to (7).

[0060] [Chemical Formula 10]

[0061] In equation (2), R 11 R represents an organic group. 12 ~R 17 Each of the above represents a hydrogen atom, a halogen atom, or an organic group independently, and * represents the bonding site with the methylene chain L of formula (1).

[0062] [Chemical Formula 11]

[0063] In equation (3), R 21 The symbol represents an organic group, ring S represents a hydrocarbon ring with a fused ring structure that may have substituents or a heterocycle with a fused ring structure that may have substituents, and is spirobonded to an adjacent pyrrole ring, ring T represents an aromatic hydrocarbon ring that may have substituents, an aromatic heterocycle that may have substituents, or a fused ring containing such ring structures that may have substituents, and * represents a bonding site with the methylene chain L of formula (1).

[0064] [Chemical Formula 12]

[0065] In equation (4), R 31 R represents an organic group. 32 ~R 35 Each can independently represent a hydrogen atom, a halogen atom, or an organic group, or R 32 With R 33 R 33 With R 34 R 34 With R 35 They can be connected to form a ring, Y 1 Represents oxygen atom, sulfur atom, CH=CH or CR 36 R 37 R 36 and R 37 Each represents an organic group, and * represents the bonding site with the methylene chain L of formula (1).

[0066] [Chemical Formula 13]

[0067] In equation (5), R 41 ~R 44 Each can independently represent a hydrogen atom, a halogen atom, or an organic group, or R 41 With R 42 R 43 With R 44 They can be connected to form a ring, Y 2 Represents oxygen atom, sulfur atom, or NR. 45 R 45represents an organic group, and * represents the bonding site with the methylene chain L of formula (1).

[0068] [Chemical Formula 14]

[0069] In equation (6), R 51 ~R 54 Each can independently represent a hydrogen atom, a halogen atom, or an organic group, Y 3 Represents oxygen atom, sulfur atom, or NR. 55 R 55 represents an organic group, and * represents the bonding site with the methylene chain L of formula (1).

[0070] [Chemical Formula 15]

[0071] In equation (7), R 61 ~R 63 R 65 ~R 67 Each can independently represent a hydrogen atom, a halogen atom, or an organic group, R 64 represents an organic group, and * represents the bonding site with the methylene chain L of formula (1).

[0072] In equations (2) to (7), R 12 ~R 17 R 32 ~R 35 R 41 ~R 44 R 51 ~R 54 R 61 ~R 63 R 65 ~R 67 Halogen atoms (halogenated groups) can be listed as follows: fluorine atom (fluorinyl group), chlorine atom (chloroyl group), bromine atom (bromoyl group), iodine atom (iodyl group), etc. R 11 ~R 17 R 21 R 31 ~R 35 R 41 ~R 44 R 51 ~R 55 R 61 ~R 67 For details on the organic groups, please refer to the description of the organic groups of substituent P above.

[0073] In equation (2), R 11Preferably, it is an alkyl, aryl, or aralkyl group, more preferably an alkyl group. Examples of such alkyl groups include straight-chain or branched alkyl groups, more preferably straight-chain alkyl groups. 11 The alkyl group preferably has 3 or more carbon atoms, more preferably 4 or more, and preferably 12 or less, more preferably 10 or less, and even more preferably 8 or less.

[0074] In equation (2), R 12 ~R 17 Preferably, the atom is a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an aralkyl group, or an amino group; more preferably, it is a hydrogen atom, a halogen atom, an alkyl group, or an alkoxy group; and even more preferably, it is a hydrogen atom, an alkyl group, or an alkoxy group. The alkyl group or alkoxy group preferably has 1 to 8 carbon atoms, more preferably 1 to 5, and even more preferably 1 to 3; the aryl group or aryloxy group preferably has 6 to 12 carbon atoms, more preferably 6 to 10; and the aralkyl group preferably has 7 to 13 carbon atoms, more preferably 7 to 11.

[0075] In equation (3), R 21 Preferably, it is an alkyl, aryl, or aralkyl group, more preferably an alkyl group. Examples of such alkyl groups include straight-chain or branched alkyl groups, more preferably straight-chain alkyl groups. 21 The alkyl group preferably has 1 to 12 carbon atoms, more preferably 1 to 6, even more preferably 1 to 3, and particularly preferably methyl or ethyl.

[0076] In formula (3), ring S represents a hydrocarbon ring or a heterocycle with a fused ring structure. The hydrocarbon ring and heterocycle of ring S may or may not be aromatic. The number of ring elements in ring S is not particularly limited, but the number of ring elements in the hydrocarbon ring or heterocycle spirobonded to the adjacent pyrrole ring is preferably 5 to 8, more preferably 5 to 7, and even more preferably 5 or 6. Examples of hydrocarbon rings or heterocycles with fused ring structures that are ring S include: indene ring, naphthalene ring, anthracene ring, fluorene ring, benzo[a]fluorene ring, indole ring, isoindole ring, benzimidazole ring, quinoline ring, benzo[a]pyran ring, acridine ring, xanthonium ring, carbazole ring, purine ring, pteridine ring, etc.

[0077] Regarding group A as shown in formula (3) + Anthocyanin compounds with group A exhibit a twisted bonding configuration due to the spirobonding of ring S with the adjacent pyrrole ring. This twisting of the anthocyanin compound affects the band gap, potentially leading to longer absorption wavelengths. Furthermore, the association or aggregation of anthocyanin compounds is suppressed, resulting in improved solubility in organic solvents or resins.

[0078] The hydrocarbon ring or heterocycle of ring S may have substituents, including organic groups and polar functional groups. Details of these organic groups and polar functional groups are provided in the description of the organic groups and polar functional groups of substituent P described above. Preferably, the substituents that ring S may have are alkyl, alkoxy, alkylthio, alkoxycarbonyl, aryl, aryloxycarbonyl, or halogroups; more preferably, they are alkyl, alkoxy, alkoxy, halogroups, or aryl; and more preferably, they are alkyl, alkoxy, or halogroups.

[0079] Ring S preferably has π bonds, specifically, it is preferred that the hydrocarbon ring or heterocycle spirobonded to the pyrrole ring has π bonds. This facilitates a configuration where ring S as a whole is twisted relative to the pyrrole ring, increasing the molecular twist of the anthocyanin compound. In this case, it is preferable that the first and second adjacent atoms of the carbon atom spirobonded to the pyrrole ring are connected by π bonds. Examples of π bonds include double bonds, such as carbon-carbon double bonds, carbon-nitrogen double bonds, and nitrogen-nitrogen double bonds. A portion of the π bonds in ring S with the adjacent pyrrole-spirobonded hydrocarbon ring or heterocycle may be shared with the fused ring.

[0080] In ring S, a fused ring is preferably formed by sharing the bonds of the first and second adjacent atoms of the carbon atom spirobonded with the pyrrole ring. Thus, ring S is formed loosely in a twisted state relative to the pyrrole ring, which increases the molecular twist of the anthocyanin compound.

[0081] Ring S is particularly preferred to be a hydrocarbon ring or a heterocycle with a fused ring structure as shown in formulas (8-1) to (8-4) below. In formulas (8-1) to (8-4) below, ring U... 1 ~ Ring U 6 Each independently represents a hydrocarbon ring that may have substituents, Y 11 Y represents -CH2-, -NH-, -O-, or -S-. 12 ~Y 16 Each can independently represent -CH2-, -CH=, -NH-, -N=, -O-, or -S-, with * indicating a site spirotropically bonded to an adjacent pyrrole ring. As a ring U 1 ~ Ring U 6 For the substituents that may be present, please refer to the description of the substituents that ring S may have above.

[0082] [Chemical Formula 16]

[0083] As a ring U 1 ~ Ring U 6Hydrocarbon rings can be categorized as aromatic or aliphatic. Examples of aromatic hydrocarbon rings include benzene, naphthalene, phenanthrene, anthracene, and fluoranthene rings. Aromatic hydrocarbon rings can have only one ring structure or be formed by the fusion of two or more ring structures. Examples of aliphatic hydrocarbon rings include monocyclic cycloalkanes with 3 to 10 carbon atoms, such as cyclopentane, cyclohexane, and cycloheptane; and monocyclic cycloalkenes with 3 to 10 carbon atoms, such as cyclopentene, cyclopentadiene, cyclohexene, cyclohexadiene (e.g., 1,3-cyclohexadiene), cycloheptene, and cycloheptadiene. 1 ~ Ring U 6 Preferably, it is a monocyclic cycloalkene or benzene ring with 3 to 10 carbon atoms (preferably 5 to 8 carbon atoms), and more preferably a benzene ring (specifically, a benzene ring with a 5-membered or 6-membered ring condensed with a spirobond at the * position).

[0084] In formula (3), ring T represents an aromatic hydrocarbon ring, an aromatic heterocycle, or a fused ring containing these ring structures, which may have substituents. Anthocyanin compounds have ring T, therefore, the π-electron system extends broadly from the methine chain L through the pyrrole ring to ring T, enabling the pursuit of longer absorption wavelengths.

[0085] Regarding aromatic hydrocarbon rings of ring T, there are no particular limitations as long as they are composed of carbon and hydrogen atoms and possess aromaticity. Examples include: benzene rings, naphthalene rings, phenanthrene rings, anthracene rings, and fluoranthene rings. Aromatic hydrocarbon rings can have only one ring structure or can be formed by the condensation of two or more ring structures. For aromatic heterocycles of ring T, there are no particular limitations as long as their ring structure contains one or more atoms selected from N (nitrogen atom), O (oxygen atom), and S (sulfur atom) and possesses aromaticity. Examples include: furan rings, thiophene rings, pyrrole rings, pyrazole rings, oxazole rings, thiazole rings, imidazole rings, pyridine rings, pyridazine rings, pyrimidine rings, pyrazine rings, purine rings, and pteridine rings. Aromatic heterocycles can have only one ring structure or can be formed by the condensation of two or more ring structures. Fused rings containing these ring structures have structures formed by the condensation of aromatic hydrocarbon rings and aromatic heterocycles, such as: indole rings, isoindole rings, benzimidazole rings, quinoline rings, benzopyran rings, acridine rings, xanthan rings, carbazole rings, etc.

[0086] Ring T may have substituents, including organic groups and polar functional groups. Details of these organic groups and polar functional groups are provided in the description of the organic groups and polar functional groups of substituent P described above. Preferred substituents for ring T include alkyl, alkoxy, alkylthio, alkoxycarbonyl, aryl, aryloxycarbonyl, amino, cyano, halogroup, and nitro groups; more preferably, alkyl, alkoxy, alkoxy, halogroup, and aryl groups. When ring T has substituents, the number is preferably 1 to 5, more preferably 1 to 3, and even more preferably 1 to 2. When ring T has multiple substituents, the substituents may be the same or different. Ring T may also be unsubstituented.

[0087] The number of π electrons contained in ring T, i.e., the number of π electrons contained in the aforementioned aromatic hydrocarbon ring, aromatic heterocycle, or fused ring containing these ring structures, is not particularly limited; for example, it can be 4 or more, or 6 or more. The upper limit of the number of π electrons contained in ring T is not particularly limited, but is preferably 18 or less, more preferably 14 or less, and even more preferably 10 or less. It should be noted that the number of π electrons contained in ring T refers to the number of π electrons in the carbon-carbon bonds shared by ring T and the pyrrole ring. From the perspective of ease of manufacture of cyanine compounds, ring T is preferably an aromatic hydrocarbon ring, and particularly preferably a benzene ring or a naphthalene ring.

[0088] In equation (4), R 31 Preferably, it is an alkyl, aryl, or aralkyl group, more preferably an alkyl group. Examples of such alkyl groups include straight-chain or branched alkyl groups, more preferably straight-chain alkyl groups. 11 The alkyl group preferably has 3 or more carbon atoms, more preferably 4 or more, and preferably 12 or less, more preferably 10 or less, and even more preferably 8 or less.

[0089] In equation (4), when R 32 ~R 35 In the case of R being an independent group, 32 ~R 35 Each of the following components is preferably composed of a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an aralkyl group, or an amino group; more preferably, a hydrogen atom, a halogen atom, an alkyl group, or an alkoxy group; and even more preferably, a hydrogen atom, an alkyl group, or an alkoxy group. The alkyl or alkoxy group preferably has 1 to 8 carbon atoms, more preferably 1 to 5, and even more preferably 1 to 3; the aryl or aryloxy group preferably has 6 to 12 carbon atoms, more preferably 6 to 10; and the aralkyl group preferably has 7 to 13 carbon atoms, more preferably 7 to 11.

[0090] In equation (4), R is... 32 With R 33 R 33 With R 34 R34 With R 35 The interconnected rings (hereinafter referred to as "rings R") can include hydrocarbon rings and heterocycles, and these ring structures may or may not be aromatic. Examples of rings R include: aromatic hydrocarbon rings, aromatic heterocycles, non-aromatic hydrocarbon rings, and non-aromatic heterocycles. The number of ring elements in ring R is preferably 5 to 8, more preferably 5 to 7, and even more preferably 5 or 6.

[0091] Aromatic hydrocarbons and aromatic heterocycles of ring R are described above for ring T. Examples of non-aromatic hydrocarbon rings of ring R include aliphatic hydrocarbon rings, such as monocyclic cycloalkanes with 3 to 10 carbon atoms, including cyclopentane, cyclohexane, and cycloheptane; and monocyclic cycloalkenes with 3 to 10 carbon atoms, including cyclopentene, cyclopentadiene, cyclohexene, cyclohexadiene (e.g., 1,3-cyclohexadiene), cycloheptene, and cycloheptadiene. Examples of non-aromatic heterocycles of ring R include rings in which one or more carbon atoms constituting the aforementioned aliphatic hydrocarbon rings are replaced by at least one atom selected from N (nitrogen), S (sulfur), and O (oxygen). Examples of non-aromatic heterocycles include: pyrrolidine rings, tetrahydrofuran rings, tetrahydrothiophene rings, piperidine rings, tetrahydropyran rings, tetrahydrothioran rings, morpholine rings, hexamethyleneimine rings, hexamethylene oxide rings, hexamethylene sulfide rings, and heptamethyleneimine rings. Ring R can also have a fused ring structure formed by condensation with other rings. Examples of such ring structures include: indene rings, fluorene rings, benzo[a]fluorene rings, indole rings, isoindole rings, benzimidazole rings, quinoline rings, benzo[a]pyran rings, acridine rings, xanthones, carbazole rings, purine rings, and pteridine rings.

[0092] Ring R may have substituents, including organic groups and polar functional groups. Details of these organic groups and polar functional groups are provided in the descriptions of the organic groups and polar functional groups of substituent P above. Halogenated groups are preferred as polar functional groups. When ring R has multiple substituents, these substituents may be the same or different. Ring R may also be unsubstituented.

[0093] In equation (4), when Y 1 In the case of CH=CH, group A + And group A has a quinoline skeleton. When Y 1 Indicates CR 36 R 37 In the case of R 36 and R 37 For details regarding the organic groups, please refer to the description of the organic groups of substituent P above. R 36 and R 37Each of the following components is preferably a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group, an aralkyl group, or an amino group, and more preferably a hydrogen atom, an alkyl group, an aryl group, or an aralkyl group. The alkyl or alkoxy group preferably has 1 to 8 carbon atoms, more preferably 1 to 5, and even more preferably 1 to 3; the aryl group preferably has 6 to 12 carbon atoms, more preferably 6 to 10; and the aralkyl group preferably has 7 to 13 carbon atoms, more preferably 7 to 11.

[0094] In equation (5), when R 41 ~R 44 In the case of R being an independent group, 41 ~R 44 Each of the following components is preferably composed of a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an aralkyl group, or an amino group; more preferably, a hydrogen atom, a halogen atom, an alkyl group, or an alkoxy group; and even more preferably, a hydrogen atom, an alkyl group, or an alkoxy group. The alkyl or alkoxy group preferably has 1 to 8 carbon atoms, more preferably 1 to 5, and even more preferably 1 to 3; the aryl or aryloxy group preferably has 6 to 12 carbon atoms, more preferably 6 to 10; and the aralkyl group preferably has 7 to 13 carbon atoms, more preferably 7 to 11.

[0095] In equation (5), R 41 With R 42 R 43 With R 44 When rings are interconnected to form a loop, refer to the description of ring R above.

[0096] In equation (5), when Y 2 Indicates NR 45 In the case of R 45 For details regarding the organic groups, please refer to the description of the organic groups of substituent P above. R 45 Preferably, the atom is a hydrogen atom, an alkyl group, an aryl group, or an aralkyl group, more preferably a hydrogen atom or an alkyl group. The alkyl group preferably has 1 to 8 carbon atoms, more preferably 1 to 5, and even more preferably 1 to 3; the aryl group preferably has 6 to 12 carbon atoms, more preferably 6 to 10; and the aralkyl group preferably has 7 to 13 carbon atoms, more preferably 7 to 11.

[0097] In equation (6), when R 51 ~R 54 In the case of R being an independent group, 51 ~R 54Each of the following components is preferably composed of a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an aralkyl group, or an amino group; more preferably, a hydrogen atom, a halogen atom, an alkyl group, or an alkoxy group; and even more preferably, a hydrogen atom, an alkyl group, or an alkoxy group. The alkyl or alkoxy group preferably has 1 to 8 carbon atoms, more preferably 1 to 5, and even more preferably 1 to 3; the aryl or aryloxy group preferably has 6 to 12 carbon atoms, more preferably 6 to 10; and the aralkyl group preferably has 7 to 13 carbon atoms, more preferably 7 to 11.

[0098] In equation (6), when Y 3 Indicates NR 55 In the case of R 55 For details regarding the organic groups, please refer to the description of the organic groups of substituent P above. R 55 Preferably, the atom is a hydrogen atom, an alkyl group, an aryl group, or an aralkyl group, more preferably a hydrogen atom or an alkyl group. The alkyl group preferably has 1 to 8 carbon atoms, more preferably 1 to 5, and even more preferably 1 to 3; the aryl group preferably has 6 to 12 carbon atoms, more preferably 6 to 10; and the aralkyl group preferably has 7 to 13 carbon atoms, more preferably 7 to 11.

[0099] In equation (7), when R 61 ~R 67 In the case of R being an independent group, 61 ~R 67 Each of the following components is preferably composed of a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an aralkyl group, or an amino group; more preferably, a hydrogen atom, a halogen atom, an alkyl group, or an alkoxy group; and even more preferably, a hydrogen atom, an alkyl group, or an alkoxy group. The alkyl or alkoxy group preferably has 1 to 8 carbon atoms, more preferably 1 to 5, and even more preferably 1 to 3; the aryl or aryloxy group preferably has 6 to 12 carbon atoms, more preferably 6 to 10; and the aralkyl group preferably has 7 to 13 carbon atoms, more preferably 7 to 11.

[0100] In equation (1), X - The term refers to a monovalent anion with a pKa of -8.0 or less, representing a conjugate acid. In the anthocyanin compound of the present invention, a cation having an anthocyanin backbone forms a salt with a monovalent anion of the conjugate acid with a pKa of -8.0 or less. This improves the solubility of the anthocyanin compound in resin.

[0101] Acids with pKa below -8.0 can be listed in Table 1 of Agnes Kutt et al., “Equilibrium Acidities of Super acids”, J. Org. Chem., 76, 391-395 (2011). Where the pKa value is known in the literature, it is cited; where it is not known, a calculated value obtained using Advanced Chemistry Development (ACD / Labs) software can be used. - The pKa of the conjugate acid of the anion is preferably -10.0 or less, more preferably -11.0 or less, and even more preferably -18.0 or less. - The anion is preferably a low nucleophilic anion, and more preferably an anion formed by the dissociation of a low pKa acid, commonly known as a super acid, into a proton.

[0102] As X - Anions, for example, can be represented by the anions shown in formulas (9-1) to (9-3) below. In formulas (9-1) to (9-3), R 81 ~R 87 Each can independently represent a fluorine atom, fluoroalkyl group, fluoroaryl group, or cyano group, R 88 and R 89 Each can independently represent a fluorine atom, fluoroalkyl group, fluoroaryl group, cyano group, or -SO2-R. 90 R 90 It represents a fluorine atom, a fluoroalkyl group, a fluoroaryl group, or a cyano group.

[0103] [Chemical Formula 17]

[0104] Additionally, X - In addition to the anions in formulas (9-1) to (9-3), the anions can also be perchlorate ions, fluorosulfonate ions, fluoroalkylsulfonate ions, cyanoalkylsulfonate ions, 2,4,6-trinitrobenzenesulfonate ions, 1,1,3,3-tetracyanoallyl ions, fluorophosphate ions, fluoroantimonate ions, etc.

[0105] In equations (9-1) to (9-3), R 81 ~R 90 The fluoroalkyl group can be linear, branched, or cyclic, preferably linear or branched, and more preferably linear. The fluoroalkyl group preferably has 1 to 8 carbon atoms, more preferably 1 to 6, and even more preferably 1 to 4. Furthermore, it is preferably a perfluoroalkyl group. 81 ~R 90The number of carbon atoms in the fluoroaryl group is preferably 6 to 12, more preferably 6 to 10, and preferably perfluoroaryl. Furthermore, in the above description, the fluoroalkyl sulfonate ion, fluorophosphate ion, and fluoroantimonate ion listed as anions other than those in formulas (9-1) to (9-3) are preferably perfluoroalkyl sulfonate ions, hexafluorophosphate ions, and hexafluoroantimonate ions, respectively. The number of carbon atoms in the alkyl group of the fluoroalkyl sulfonate ion is preferably 1 to 8, more preferably 1 to 6, and even more preferably 1 to 4.

[0106] X - The preferred anion is the anion represented by formula (9-1), namely borate ion, which further improves the solubility of the anthocyanin compound in the resin. In this case, R 81 ~R 84 More preferably, it is fluoroalkyl, fluoroaryl, or cyano, even more preferably fluoroalkyl or fluoroaryl, and particularly preferably fluoroaryl. The borate ion having a pKa of -8.0 or less and possessing a fluoroaryl group is an example of a tetra(pentafluorophenyl)borate anion (the pKa of which is about -30).

[0107] The cyanine compound used in this invention preferably has an average transmittance of 81% or more in the wavelength range of 380nm to 780nm, with a transmittance of 10% at the wavelength of maximum absorption. Thus, the cyanine compound transmits light in the visible light range with high transmittance, and the material used for laser welding is substantially free of coloration from the cyanine compound. More preferably, the average transmittance of the cyanine compound in the wavelength range of 380nm to 780nm is 85% or more, and even more preferably 88% or more.

[0108] The anthocyanin compound preferably has a maximum absorption wavelength in the wavelength range of 750 nm to 1300 nm. Specifically, the anthocyanin compound preferably has an absorption peak with maximum absorption in the wavelength range of 750 nm to 1300 nm in its absorption spectrum, and the maximum absorption of this absorption peak is at its maximum value in the wavelength range of 600 nm to 1300 nm. The maximum absorption wavelength of the anthocyanin compound can be 780 nm or more, 800 nm or more, 850 nm or more, 900 nm or more, or 1000 nm or more, and can also be 1280 nm or less, 1200 nm or less, 1150 nm or less, or 1100 nm or less.

[0109] The full width at half maximum (FWHM) of the absorption peak providing the maximum absorption wavelength of the anthocyanin compound is preferably 40 nm or more, more preferably 45 nm or more, and even more preferably 50 nm or more. This allows for laser absorption over a wide wavelength range, enabling the use of various lasers in laser welding. Conversely, the FWHM of the absorption peak providing the maximum absorption wavelength of the anthocyanin compound is preferably 100 nm or less, more preferably 80 nm or less, and even more preferably 60 nm or less. This facilitates improved transmittance of light in the visible light range.

[0110] The absorption spectra of anthocyanin compounds described above refer to their absorption spectra in chloroform. Additionally, the full width at half maximum (FWHM) refers to the width of the absorption peak representing 50% of the transmittance when the transmittance at the maximum absorption wavelength is 10%.

[0111] The resin used in laser welding materials is not particularly limited as long as it melts when irradiated with a laser, allowing the components to fuse together, but thermoplastic resins are preferred. This ensures that the resin in the laser welding material melts when irradiated with a laser, facilitating the fusion of components. The resin can be either a polymerized resin or a resin raw material (including resin precursors, raw materials for those precursors, monomers constituting the resin, etc.), which undergoes a polymerization or cross-linking reaction and is incorporated into the resin during use.

[0112] Resins used as materials for laser welding include, for example: (meth)acrylic resins, (meth)acrylic polyurethane resins, polyacrylic acid and its salts, polyacrylamide, polyvinyl chloride resins, polyvinylidene chloride resins, polyvinylpyrrolidone, polyolefin resins (e.g., polyethylene resin, polypropylene resin), cycloolefin resins, polyethyleneimine, melamine resins, polyurethane resins, polystyrene resins, polyvinyl acetate, polyamide resins (e.g., nylon), aramid resins, polyimide resins, polyamide-imide resins, alkyd resins, phenolic resins, epoxy resins, polyester resins (e.g., polybutylene terephthalate (PBT) resin, polyethylene terephthalate (PET) resin, polyarylate resins, etc.), polysulfone resins, polyethersulfone resins, and poly... Sulfonamides and their salts, butyraldehyde resins, polycarbonate resins, polyacetal resins, polyether resins, polyphenylene sulfide resins, ABS resins (acrylonitrile-butadiene-styrene resins), AS resins (acrylonitrile-styrene copolymers), styrene-maleic anhydride copolymers, silicone resins, modified silicone resins (e.g., (meth)acrylate silicone resins, alkyl polysiloxane resins, silicone polyurethane resins, silicone polyester resins, silicone acrylic resins, etc.), fluorinated resins (e.g., fluorinated aromatic polymers, polytetrafluoroethylene (PTFE), perfluoroalkoxy fluoropolymers (PFA), fluorinated polyaryletherketones (FPEK), fluorinated polyimide (FPI), fluorinated polyamic acid (FPAA), fluorinated polyether nitrile (FPEN), etc.), carboxymethyl cellulose, polyethylene glycol, etc. Among these, polyimide resins, polyamide-imide resins, (meth)acrylate resins, cycloolefin resins, epoxy resins, polyester resins, polyarylate resins, polyamide resins, polycarbonate resins, polysulfone resins, and fluorinated aromatic polymers are preferred. These resins have high transparency, which allows for a good appearance of the weld when components are fused together using laser welding materials.

[0113] Polyimide resins are polymers in which imide bonds are contained in the repeating units of the main chain. For example, they can be manufactured by polyamic acid obtained by polycondensation of tetracarboxylic dianhydride and diamine, followed by dehydration / cyclization (imidization). As polyimide resins, aromatic polyimides formed by aromatic rings linked by imide bonds are preferred. Examples of polyimide resins that can be used include: NEOPULIM (registered trademark) manufactured by Mitsubishi Gas Chemical, Kapton (registered trademark) manufactured by DuPont, AURUM (registered trademark) manufactured by Mitsui Chemicals, Meldin (registered trademark) manufactured by Saint-Gobain, and the TPS (registered trademark) TI3000 series manufactured by Toray Plastics Precision.

[0114] Polyamide-imide resins are polymers in which repeating units of the main chain contain amide and imide bonds. Examples of polyamide-imide resins that can be used include: Torlon (registered trademark) manufactured by Solvay Advanced Polymers, Vylomax (registered trademark) manufactured by Toyobo Co., Ltd., and the TPS (registered trademark) TI5000 series manufactured by Toray Plastics Precision.

[0115] (Meth)acrylic acid resins are polymers having repeating units derived from (meth)acrylic acid or its derivatives, such as poly(meth)acrylate resins, which preferably have repeating units derived from (meth)acrylates. The main chain of a (meth)acrylic acid resin preferably has a ring structure, such as: lactone ring structures, glutaric anhydride structures, glutarimide structures, maleic anhydride structures, maleimide ring structures, and other carbonyl-containing ring structures; and oxetane ring structures, azirone ring structures, tetrahydrofuran ring structures, pyrrolidine ring structures, tetrahydropyran ring structures, piperidine ring structures, and other carbonyl-free ring structures. It should be noted that carbonyl-containing ring structures also include structures containing carbonyl derivative groups such as imide groups. (Meth)acrylic resins having a carbonyl ring structure can be, for example, those described in Japanese Patent Application Publication No. 2004-168882, Japanese Patent Application Publication No. 2008-179677, International Publication No. 2005 / 54311, and Japanese Patent Application Publication No. 2007-31537.

[0116] Cycloolefin resins are polymers obtained by polymerizing cycloolefins as at least a portion of the monomer components. There are no particular limitations on the type of resin, as long as it has an alicyclic structure in a portion of the main chain. Examples of cycloolefin resins include TOPAS (registered trademark) manufactured by POLYPLASTICS, APEL (registered trademark) manufactured by Mitsui Chemicals, ZEONEX (registered trademark) and ZEONOR (registered trademark) manufactured by ZEON Corporation of Japan, and ARTON (registered trademark) manufactured by JSR Corporation.

[0117] Epoxy resin is a resin that can be cured by cross-linking epoxy compounds (prepolymers) in the presence of a curing agent and a curing catalyst. Examples of epoxy compounds include aromatic epoxy compounds, aliphatic epoxy compounds, alicyclic epoxy compounds, and hydrogenated epoxy compounds. Examples include fluorene-based epoxy resin (OGSOL PG-100) manufactured by Osaka Gas Chemicals, bisphenol A type epoxy compound (JER 828EL) and hydrogenated bisphenol A type epoxy compound (JER YX8000) manufactured by Mitsubishi Chemicals, and alicyclic liquid epoxy compound (CELLOXIDE 2021P) manufactured by Diacel.

[0118] Polyester resins are polymers in which ester bonds are contained in the repeating units of the main chain. They can be obtained, for example, by polycondensation of a polycarboxylic acid (dicarboxylic acid) with a polyol (diol). Examples of polyester resins include polyethylene terephthalate, polybutylene terephthalate, polypropylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate. For example, Osaka Gas Chemicals' OKP series, Teijin's TRN series, TEONEX (registered trademark), DuPont's Rynite (registered trademark), Mitsubishi Chemical's NOVAPEX (registered trademark), Mitsubishi Engineering Plastics' NOVADURAN (registered trademark), Toray's LUMIRROR (registered trademark), TORAYCON (registered trademark), and Unitika's ELITEL (registered trademark).

[0119] Polyaryl ester resins are polymers obtained by polycondensation of diphenol compounds with diacids (such as aromatic dicarboxylic acids like phthalic acid), and have repeating units in the main chain containing aromatic rings and ester bonds. Examples of polyaryl ester resins include VECTRAN (registered trademark) manufactured by Kuraray, U POLYMER (registered trademark) manufactured by Unitika, and UNIFINER (registered trademark).

[0120] Polyamide resins are polymers in which amide bonds are contained in the repeating units of the main chain, and can be obtained, for example, by polycondensation of diamines with dicarboxylic acids. Polyamide resins can be polyamide resins with an aliphatic backbone in the main chain; nylon is an example of such a polyamide resin. Polyamide resins can also be polyamide resins with an aromatic backbone; aramid resins are known as such polyamide resins. From the perspective of excellent heat resistance and high mechanical strength, aramid resins are preferred; for example, Twaron (registered trademark) and CONEX (registered trademark) manufactured by Teijin Corporation, and KEVLAR (registered trademark) and NOMEX (registered trademark) manufactured by DuPont Corporation can be used.

[0121] Polycarbonate resin is a polymer in which carbonate groups (-O-(C=O)-O-) are contained in the repeating units of the main chain. Polycarbonate resins that can be used include Panlite (registered trademark) manufactured by Teijin Corporation, Multilon (registered trademark) manufactured by Mitsubishi Engineering Plastics Corporation, Iupilon (registered trademark) manufactured by Mitsubishi GasChemical Corporation, Iupizeta (registered trademark) manufactured by Mitsubishi GasChemical Corporation, Novarax (registered trademark) and Xantar (registered trademark) manufactured by SumikaStyron Polycarbonate Limited, SD Polyca (registered trademark) manufactured by Idemitsu Kosan Corporation, and Tarflon (registered trademark), among others.

[0122] Polysulfone resin is a polymer containing repeating units comprising an aromatic ring, a sulfonyl group (-SO2-), and an oxygen atom. Examples of polysulfone resins that can be used include SUMIKAEXCEL (registered trademark) PES3600P and PES4100P manufactured by Sumitomo Chemical Co., Ltd., and UDEL (registered trademark) P-1700 manufactured by Solvay Specialty Polymers Co., Ltd.

[0123] Fluorinated aromatic polymers are polymers having repeating units comprising an aromatic ring having one or more fluorine atoms and at least one bond selected from the group consisting of ether bonds, ketone bonds, sulfone bonds, amide bonds, imide bonds, and ester bonds. Preferably, the polymer must contain repeating units comprising an aromatic ring having one or more fluorine atoms and an ether bond. For example, the fluorinated aromatic polymer described in Japanese Patent Application Publication No. 2008-181121 can be used.

[0124] As the resin, a (meth)acrylic resin comprising structural units having a ring structure in the main chain is preferred. Specifically, a (meth)acrylic resin comprising structural units having a ring structure in the main chain, wherein the ring structure comprises at least one selected from the group consisting of a lactone ring structure, a glutarimide structure, and a maleimide structure, is also preferred. Using such a (meth)acrylic resin allows for the production of a laser welding material with excellent transparency. Furthermore, due to its excellent heat resistance, the welded body formed by fusing components together using this laser welding material will stably maintain the weld at high temperatures.

[0125] In the aforementioned (meth)acrylic resin, when the main chain contains a lactone ring structure, the number of ring members in the lactone ring structure is not particularly limited; for example, it can be any of a 4-membered to an 8-membered ring. It should be noted that, considering the excellent stability of the ring structure, the lactone ring structure is preferably a 5-membered or 6-membered ring, and more preferably a 6-membered ring.

[0126] As a structural unit containing a lactone ring structure, the structure shown in equation (10) below can be cited as an example. In equation (10) below, R 91 R 92 and R 93 Each can independently represent a hydrogen atom or an organic group.

[0127] [Chemical Formula 18]

[0128] In the lactone ring structural unit of formula (10), as R 91 R 92 and R 93 The organic groups can include linear or branched alkyl groups with 1 to 20 carbon atoms, cycloalkyl groups with 3 to 20 carbon atoms, alkenyl groups with 2 to 20 carbon atoms, aryl groups with 6 to 20 carbon atoms, and aralkyl groups with 7 to 20 carbon atoms. These groups can have any substituents (e.g., hydroxyl, carboxyl, alkoxy, ester, etc.). It should be noted that, considering the ease of manufacturing (meth)acrylic resins with an lactone ring structure, R... 91 and R 93 Preferably, it is an alkyl group having 1 to 6 carbon atoms, R 92 Preferably, it is an alkyl group having 1 to 6 carbon atoms.

[0129] In the above-mentioned (meth)acrylic resin, when the ring structure contained in the main chain is a glutarimide ring structure, the structure shown in the following formula (11) can be cited as a structural unit containing the glutarimide ring structure. In the following formula (11), R 94 and R 95 Each can independently represent a hydrogen atom or a methyl group, R 96It represents hydrogen atoms, straight-chain or branched alkyl groups with 1 to 20 carbon atoms, cycloalkyl groups with 3 to 12 carbon atoms, aryl groups with 6 to 10 carbon atoms, or aralkyl groups with 7 to 12 carbon atoms.

[0130] [Chemical Formula 19]

[0131] In the above-mentioned (meth)acrylic resin, when the ring structure contained in the main chain is a maleimide ring structure, the structure containing the maleimide ring structure can be exemplified by, for example, the structure shown in the following formula (12). The ring structure unit in the following formula (12) is a structural unit derived from maleimide, and can also be referred to as a structural unit containing a succinimide structure. In the following formula (12), R 97 and R 98 Each can independently represent a hydrogen atom or a methyl group, R 99 It represents hydrogen atoms, straight-chain or branched alkyl groups with 1 to 20 carbon atoms, cycloalkyl groups with 3 to 12 carbon atoms, aryl groups with 6 to 10 carbon atoms, or aralkyl groups with 7 to 12 carbon atoms.

[0132] [Chemical Formula 20]

[0133] As structural units containing a maleimide ring structure in formula (12), examples include structural units from N-methylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, N-benzylmaleimide, etc.

[0134] (Meth)acrylic resins containing structural units with a ring structure in the main chain preferably contain units derived from (meth)acrylates. By introducing (meth)acrylate units, the glass transition temperature or flowability of the (meth)acrylic resin can be adjusted. In 100% by mass of the (meth)acrylic resin, the content of structural units with a ring structure in the main chain is preferably 5% by mass or more, more preferably 10% by mass or more, further preferably 20% by mass or more, and preferably 90% by mass or less, more preferably 80% by mass or less, further preferably 70% by mass or less, and particularly preferably 60% by mass or less. (Meth)acrylic resins containing structural units with a ring structure in the main chain may contain units derived from styrene monomers.

[0135] The resin can be either transparent or opaque, but high transparency is preferred from the perspective of producing a welded body with a good appearance and expanding the application range of materials used in laser welding. For example, a total light transmittance of 75% or more is preferred when the resin has a thickness of 0.1 mm; more preferably, 80% or more; and even more preferably, 85% or more. There is no particular upper limit to the total light transmittance of the resin; a total light transmittance of 100% or less is acceptable, for example, 95% or less. The total light transmittance is measured based on JIS K 7105.

[0136] The glass transition temperature (Tg) of the resin is not particularly limited, but from the perspective of improving the heat resistance of the welded body formed by fusing components together using laser welding materials, it is preferably 110°C or higher, more preferably 120°C or higher, and even more preferably 130°C or higher. The upper limit of the glass transition temperature of the resin is not particularly limited, but from the perspective of facilitating laser welding, it is preferably 380°C or lower, more preferably 300°C or lower, and even more preferably 250°C or lower.

[0137] The content of anthocyanin compounds in the laser welding material is preferably 0.01% by mass or more, more preferably 0.03% by mass or more, and even more preferably 0.05% by mass or more, out of 100% by mass of the solid composition of the laser welding material. This allows the anthocyanin compounds in the laser welding material to generate sufficient heat when irradiated with a laser, making the resin easier to melt. As a result, it is easy to properly fuse components together using the laser welding material. On the other hand, the content of anthocyanin compounds in the laser welding material is preferably 20% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less, out of 100% by mass of the solid composition of the laser welding material. This easily improves the transparency of the laser welding material. It should be noted that the solid composition of the laser welding material refers to the amount of laser welding material after removing the solvent, in the case where the laser welding material contains a solvent.

[0138] Materials used for laser welding can also contain solvents. Including solvents facilitates the coating process of these materials. Solvents can function as solvents for cyanide compounds or as dispersion media. Examples of solvents include: alcohols such as methanol, ethanol, and isopropanol; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; diol derivatives (ether compounds, ester compounds, ether ester compounds, etc.) such as PGMEA (2-acetoxy-1-methoxypropane), ethylene glycol monobutyl ether, ethylene glycol monoethyl ether, and ethylene glycol ethyl ether acetate; amides such as N,N-dimethylacetamide and N,N-dimethylformamide; ethyl acetate, propyl acetate, etc. Esters such as butyl acetate; pyrrolidones such as N-methylpyrrolidone (specifically 1-methyl-2-pyrrolidone); aromatic hydrocarbons such as toluene, xylene, and 1,2,4-trimethylbenzene; aliphatic hydrocarbons such as cyclohexane and heptane; ethers such as tetrahydrofuran, 2-methyltetrahydrofuran, tetrahydropyran, 4-methyltetrahydropyran, dioxane, diethyl ether, and dibutyl ether; halogenated hydrocarbons such as chloroform, dichloromethane, and 1,2-dichloroethane; lactones such as γ-butyrolactone; etc. Only one of these solvents may be used, or two or more may be used in combination.

[0139] Regarding the solvent content, in 100% by mass of the laser welding material, it is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and preferably less than 100% by mass, more preferably 99% by mass or less. By adjusting the solvent content to such a range, the operability of the laser welding material is easily improved.

[0140] Materials for laser welding may contain two or more anthocyanin compounds. Furthermore, as long as the desired performance of the laser welding material is ensured, pigments other than anthocyanin compounds may be included; for example, at least one pigment selected from near-infrared absorbing pigments, visible light absorbing pigments, and ultraviolet absorbing pigments may also be included. Depending on the requirements, laser welding materials may also contain various additives such as dispersants, plasticizers, surfactants, viscosity modifiers, defoamers, preservatives, and resistivity adjusters.

[0141] Laser welding materials can be manufactured by mixing anthocyanin compounds with resin. From the perspective of easily and uniformly mixing the anthocyanin compounds with the resin, it is preferable to mix the anthocyanin compound solution (obtained by dissolving the anthocyanin compound in a solvent) with the resin. Alternatively, it is preferable to pre-mix the resin and solvent and then mix them with the anthocyanin compound solution to manufacture the laser welding material.

[0142] In the difference spectrum of transmittance between the laser welding material and the resin composition from which anthocyanin compounds have been removed, within a wavelength range of 300 nm to 1300 nm, the average transmittance in the wavelength range of 380 nm to 780 nm, where the transmittance at the maximum absorption wavelength is 10%, is preferably 81% or higher. Therefore, the laser welding material transmits light in the visible light range with high transmittance, resulting in excellent transparency and invisibility. The average transmittance in the wavelength range of 380 nm to 780 nm in this difference spectrum is more preferably 85% or higher, and even more preferably 88% or higher.

[0143] By measuring the transmission spectrum of the laser welding material and the transmission spectrum of the resin composition from which anthocyanin compounds have been removed from the laser welding material, and then performing logarithmic division on both (log... 10 The difference spectrum is obtained by performing an exponential transformation on its difference. Specifically, the transmittance of the difference spectrum can be calculated based on the following formula: Transmittance of difference spectrum (%) = 10^[log 10 (Transmittance of materials used for laser welding) - log 10 [(Transmittance of the resin composition)]×100.

[0144] Laser welding materials can be applied, for example, to components joined by laser welding. Hereinafter, the component joined by laser welding, i.e., the component coated with the laser welding material, will be referred to as a "substrate". The present invention also provides a laminate comprising: a substrate; and a light-absorbing layer disposed on the substrate, formed of the laser welding material.

[0145] The substrate can be either a laser-transmitting or laser-nontransmitting substrate. A coating of laser welding material can be formed on the substrate, and then dried or cured as needed, thereby forming a light-absorbing layer on the substrate. On the substrate with the light-absorbing layer, a component to be bonded to the substrate (hereinafter referred to as a "bonding component") is overlapped from the light-absorbing layer side. Laser light is irradiated onto the light-absorbing layer, whereby the anthocyanin compound contained in the light-absorbing layer absorbs the laser energy and generates heat, thereby melting the resin of the light-absorbing layer to fuse the substrate and the bonding component. In other words, by coating the substrate with laser welding material to form a light-absorbing layer formed by laser welding material, and by overlapping the bonding component on the substrate with the light-absorbing layer from the light-absorbing layer side and irradiating the light-absorbing layer with laser light, the substrate and the bonding component can be laser-fused.

[0146] The materials of the substrate and the joining components are not particularly limited, but from the viewpoint of facilitating a stronger weld using laser welding materials, the substrate and the joining components are preferably made of resin. The resin constituting the substrate and the joining components may be the same type as the resin contained in the laser welding materials, or it may be a different type. However, from the viewpoint of facilitating a stronger weld between the substrate and the joining components, and making the joint between the substrate and the joining components less noticeable, the substrate and the joining components are preferably made of the same type of resin as the resin contained in the laser welding materials.

[0147] The laser welding material can be coated onto a substrate using known coating methods such as spin coating, solvent casting, roller coating, spraying, rod coating, dip coating, screen printing, flexographic printing, and inkjet printing. The coating method is not limited to these methods; for example, a pen-shaped coating tool (a coating tool consisting of a container and a pen tip) can also be used. The thickness of the light-absorbing layer formed by the coating of the laser welding material is not particularly limited, but is preferably 1 mm or less, more preferably 500 μm or less, even more preferably 300 μm or less, and even more preferably 100 μm or less. It is also preferably 0.1 μm or more, more preferably 0.5 μm or more, and even more preferably 1 μm or more.

[0148] As laser fusion splicers, the following can be used: TruDiode (registered trademark) (laser wavelength: 920-1050nm) manufactured by Trumpf Corporation; WFD series (laser wavelength: 915nm) manufactured by Han's Laser Corporation; PowerWeld 2600 (laser wavelength: 980nm) manufactured by LPKF Laser & Electronics Corporation; ExactWeld 230P manufactured by Coherent Corporation; GLX series (laser wavelength: 990nm) or GL-300 (laser wavelength: 1080nm) manufactured by Emerson Electric Corporation; ML-5120 direct diode laser fusion splicer-120W (laser wavelength: 915nm) manufactured by Amada Corporation; laser fusion splicers manufactured by IPTE Factory Automation Corporation; TITAN WELD system (laser wavelength: 980nm) manufactured by EVLASER SRL Corporation; laser fusion splicers manufactured by IPG Photonics Corporation; and Panasonic. The following laser heating systems are available: VL-W1 series (laser wavelength: 1070nm) manufactured by Industry Corporation; 200W or 300W (laser wavelength: 1064nm) manufactured by Mecco Corporation; L16490-343 or L15570 series laser heating systems manufactured by Hamamatsu Photonics Corporation; FD2330 (laser wavelengths: 808nm, 940nm, 980nm) manufactured by FineDevice Corporation; LW-D30A / LW-D100 semiconductor laser welding machines (laser wavelength: 980nm) manufactured by Nippon Avionics Corporation; M720A series fiber laser processing machines manufactured by TOWA Laserfront Corporation; LS-W100 laser resin welding system (laser wavelength: 940nm) manufactured by Seidensha Electronics Corporation; and Galweld type M or type S (laser wavelength: 1070nm) manufactured by Hiroshima Corporation.

[0149] Laser irradiation can be performed from either the substrate side or the bonding member side. When laser irradiation is performed from the substrate side, a substrate that transmits laser light is used. In this case, the bonding member may or may not be a substrate that transmits laser light. When laser irradiation is performed from the bonding member side, a bonding member that transmits laser light is used. In this case, the substrate may or may not be a substrate that transmits laser light.

[0150] Examples of lasers include solid-state lasers, fiber lasers, semiconductor lasers, gas lasers, and liquid lasers. For instance, YAG lasers (wavelengths of 1064 nm and 1070 nm) and semiconductor lasers (wavelengths of 808 nm, 840 nm, 940 nm, and 980 nm) are preferred. The wavelength of the laser is preferably within the range of 800 nm to 1300 nm, more preferably 850 nm to 1200 nm, and even more preferably 900 nm to 1100 nm. Lasers with wavelengths of 940 nm, 980 nm, or 1070 nm are particularly preferred.

[0151] Laser welding materials can also be used to form absorbent materials for laser welding. Laser welding is typically performed by overlapping a transmitting material that transmits laser light with an absorbing material that absorbs laser light, and then irradiating the material with laser light from the transmitting material side. However, laser welding materials can also be used as materials to form such absorbent materials. This invention also provides absorbent materials formed from laser welding materials. The absorbent material can be formed by shaping the laser welding material into any shape, for example, by placing the laser welding material in a molding die and drying or curing it. Alternatively, sheet-like absorbent materials can be formed by pressing or stretching a semi-molten laser welding material. The absorbent material formed from the laser welding material can be welded to the transmitting material by overlapping the transmitting material and irradiating it with laser light from the transmitting material side, or by overlapping the transmitting material with absorbent material sandwiched between the transmitting materials and then irradiating it with laser light.

[0152] The shape of the substrate and the absorbing material is not particularly limited, and examples include: plate-like, sheet-like, granular, powdery, block-like, granular aggregate-like, spherical, ellipsoidal, lenticular, cubic, columnar, rod-like, conical, cylindrical, needle-like, fibrous, hollow fiber-like, porous, etc. It should be noted that if the absorbing material is sheet-like, it is preferred in terms of improving the operability of the absorbing material and expanding its application range. Sheet-like absorbing materials, i.e., absorbing material sheets, are not limited to planar substrates and can be used in conjunction with curved substrates. Furthermore, the absorbing material sheets can be formed from solvent-free laser welding materials, thus allowing the use of resin materials with low solvent resistance, thereby increasing the freedom of choice in resin materials. The thickness of the absorbing material sheet is preferably 10 μm or more, more preferably 15 μm or more, further preferably 20 μm or more, and preferably 500 μm or less, more preferably 400 μm or less, and even more preferably 300 μm or less.

[0153] The laser welding material, light-absorbing layer, or absorbing material preferably has a maximum absorption wavelength in the absorption spectrum ranging from 750 nm to 1300 nm within the wavelength range of 600 nm to 1300 nm. Specifically, it is preferable that the absorption spectrum in the wavelength range of 600 nm to 1300 nm has an absorption peak with maximum absorption in the wavelength range of 750 nm to 1300 nm, and the maximum absorption of this absorption peak is at its maximum value in the wavelength range of 600 nm to 1300 nm. If the light-absorbing layer or absorbing material has a maximum absorption wavelength in such a range, it becomes easier to perform laser welding appropriately using commonly used lasers such as YAG lasers or semiconductor lasers. The maximum absorption wavelength of the laser welding material, light-absorbing layer, or absorbing material can be 780 nm or more, 800 nm or more, 850 nm or more, 900 nm or more, or 1000 nm or more; alternatively, it can be 1280 nm or less, 1200 nm or less, 1150 nm or less, or 1100 nm or less.

[0154] As a commonly used wavelength in lasers, the transmittance of the light-absorbing layer at a wavelength of 1070 nm is preferably above 0% and below 99%. The transmittance of the light-absorbing layer at a wavelength of 1070 nm can be above 1%, above 2%, above 3%, above 5%, above 10%, above 20%, above 30%, above 40%, above 50%, above 60%, above 70%, above 80%, or above 90%.

[0155] The transmittance of the light-absorbing layer at the maximum absorption wavelength in the wavelength range of 750 nm to 1300 nm is preferably 0% or more and 99% or less. The transmittance of the light-absorbing layer at the maximum absorption wavelength can be 1% or more, 2% or more, 3% or more, 5% or more, 10% or more, 20% or more, 30% or more, 40% or more, 50% or more, 60% or more, 70% or more, 80% or more, or 90% or more.

[0156] The average transmittance of the light-absorbing layer in the wavelength range of 380 nm to 780 nm is preferably 80% or higher. Therefore, the light-absorbing layer transmits light in the visible light range with high transmittance, resulting in excellent transparency and invisibility. Consequently, the joint between the substrate and the bonding member is inconspicuous, leading to a good appearance of the welded body formed by fusing the substrate and the bonding member. The average transmittance of the light-absorbing layer in the wavelength range of 380 nm to 780 nm can be 83% or higher, or 85% or higher. In the light-absorbing layer, the average transmittance in the wavelength range of 380 nm to 780 nm is preferably higher than the transmittance at a wavelength of 1070 nm, and more preferably higher than the transmittance at the maximum absorption wavelength in the wavelength range of 750 nm to 1300 nm.

[0157] The absorbing material formed from the laser welding material, at a wavelength commonly used in lasers, preferably has a transmittance of 0% or more and 99% or less at a wavelength of 1070 nm. The transmittance of the absorbing material at a wavelength of 1070 nm can be 1% or more, 2% or more, 3% or more, 5% or more, 10% or more, 20% or more, 30% or more, 40% or more, 50% or more, 60% or more, 70% or more, 80% or more, or 90% or more; alternatively, it can be 98% or less, 97% or less, 95% or less, or 93% or less.

[0158] The transmittance of the absorbing material formed from the laser welding material at the maximum absorption wavelength in the wavelength range of 750 nm to 1300 nm is preferably 0% or more and 99% or less. The transmittance of the absorbing material at the maximum absorption wavelength can be 1% or more, 2% or more, 3% or more, 5% or more, 10% or more, 20% or more, 30% or more, 40% or more, 50% or more, 60% or more, 70% or more, 80% or more, or 85% or more, and can also be 98% or less, 97% or less, 95% or less, 93% or less, or 90% or less.

[0159] The absorbing material formed from the laser welding material can be either a high-transmittance absorbing material in the visible light range or a low-transmittance absorbing material in the visible light range. The average transmittance of the absorbing material formed from the laser welding material in the wavelength range of 380 nm to 780 nm can be 70% or more, 73% or more, or 75% or more. Preferably, the average transmittance of the absorbing material formed from the laser welding material in the wavelength range of 380 nm to 780 nm is higher than the transmittance at a wavelength of 1070 nm, and more preferably higher than the transmittance at the maximum absorption wavelength in the wavelength range of 750 nm to 1300 nm.

[0160] This application claims the benefit of priority based on Japanese Patent Application No. 2023-197624, filed on November 21, 2023. The entire contents of the description of Japanese Patent Application No. 2023-197624, filed on November 21, 2023, are incorporated herein by reference.

[0161] Example The present invention is illustrated below with specific examples, but the present invention is not limited to the following examples. It may also be implemented by appropriate modifications within the scope of the preceding and following text, and all such modifications are included within the technical scope of the present invention.

[0162] (1) Synthesis of compounds (1-1) Synthesis Example 1: Synthesis of anthocyanin compound 1 In a 500 mL four-necked flask placed in a water bath, under nitrogen flow (10 mL / min), while monitoring for heating, 21.9 g (0.195 mol) of potassium tert-butoxide, 98.1 g of superhydrofuran, 10.8 g (0.065 mol) of fluorene, and 11.5 g (0.13 mol) of ethyl acetate were added sequentially. The mixture was then heated in the water bath while stirring under reflux for 3 hours. After cooling, the resulting reaction solution was quenched with dilute hydrochloric acid, extracted with ethyl acetate, and washed three times with brine. The resulting organic phase was dehydrated with magnesium sulfate, concentrated using an evaporator, and then purified by silica gel column chromatography (developing solvent: ethyl acetate) to obtain 12.5 g of 9-acetyl-9H-fluorene.

[0163] To a 500 mL separable flask, 6.2 g (0.026 mol) of 9-acetyl-9H-fluorene, 5.0 g (0.026 mol) of 1-phenylhydrazine hydrochloride, and 112.1 g of tert-amyl alcohol as solvent were added. The mixture was stirred under nitrogen (10 mL / min) at 90 °C for 4 hours. After the reaction was complete, the reaction solution was cooled to room temperature, quenched with 100 g of water, and extracted with 100 g of ethyl acetate. The resulting organic phase was dehydrated with magnesium sulfate, concentrated using an evaporator, and then purified by silica gel column chromatography (developing solvent: chloroform) to give 5.1 g of indolenine compound 1.

[0164] Next, 2.0 g (0.007 mol) of the aforementioned pseudoindole compound 1, 11.2 g (0.079 mol) of iodomethane, and 53.3 g of N,N-dimethylformamide were added to a 100 mL four-necked flask. The mixture was stirred at 80 °C for 6 hours under nitrogen flow (5 mL / min). After cooling to room temperature, the reaction solution was precipitated in 300 g of toluene. The precipitated solid was filtered to obtain 1.8 g of indoleonium salt 1.

[0165] [Chemical Formula 21]

[0166] N-((1E)-2-phenyl-3-((E)-(phenylimino)methyl)cyclohexane-2-en-1-yl)methylaniline hydrochloride (diphenylamine salt 1) was synthesized according to the method described in Bioconjugate Chemistry, 29(11), pp.3886-3895(2018). In a 100 mL four-necked flask, 1.0 g (0.0021 mol) of the aforementioned indolonium salt 1, 0.42 g (0.0011 mol) of diphenylamine salt 1, 0.28 g (0.003 mol) of sodium acetate, 9.9 g of acetic acid, and 10.1 g of acetic anhydride were added, and the mixture was stirred at 100 °C for 8 hours. The reaction mixture was cooled to room temperature, and 150 g of water was added. The precipitated solid was filtered off. The solid was purified by silica gel column chromatography (developing solvent: chloroform) to give 0.21 g of the iodide salt of anthocyanin compound 1.

[0167] [Chemical Formula 22]

[0168] 0.50 g (0.50 mmol) of the iodide salt of anthocyanin compound 1 was dissolved in 20 mL of acetone, and 6.7 g (0.10 mmol) of a 10.5% aqueous solution of sodium tetra(pentafluorophenyl)borate (manufactured by Nippon Shokubai Co., Ltd.) was added. The mixture was stirred overnight at room temperature. The reaction solution was concentrated using an evaporator and purified by silica gel column chromatography (developing solvent: chloroform) to obtain 0.57 g of anthocyanin compound 1 as shown in Table 1. It should be noted that the pKa of the tetra(pentafluorophenyl)borate anion of anthocyanin compound 1 is below -8.0.

[0169] [Chemical Formula 23]

[0170] (1-2) Synthesis Example 2: Synthesis of anthocyanin compound 2 Using 3-butyl-2-(2-[3-[2-(3-butyl-1,1-dimethyl-1,3-dihydrobenzo[e]indol-2-ethylene]ethylene]-2-chloro-cyclohexyl-1-enyl]vinyl)-1,1-dimethyl-1H-benzo[e]indolium hexafluorophosphate (Few Chemicals, S0712) as the starting anthocyanin compound, 1.00 g (1.2 mmol) of this starting anthocyanin compound was dissolved in 100 g of acetone, and 9.00 g (1.4 mmol) of a 10.5% sodium tetra(pentafluorophenyl)borate aqueous solution heated to 40 °C was added. The mixture was stirred at room temperature for 2 hours. The solvent was then removed by distillation, and the resulting solid was washed with deionized water to obtain 1.47 g of anthocyanin compound 2 as shown in Table 1.

[0171] (1-3) Synthesis Example 3: Synthesis of anthocyanin compound 3 In Synthesis Example 2, 6-butoxy-2-[5-(6-butoxy-1-butyl-1H-benzo[cd]indol-2-ylidene)-pentyl-1,3-dienyl]-1-butyl-benzo[cd]indolium tetrafluoroborate (Few Chemicals, S2437) was used as the starting anthocyanin compound. Otherwise, the procedure was the same as in Synthesis Example 2, and 1.23 g of the anthocyanin compound 3 shown in Table 1 was obtained.

[0172] (1-4) Synthesis Example 4: Synthesis of anthocyanin compound 4 In Synthesis Example 2, 1-butyl-2-(2-[3-(2-[1-butyl-1H-benzo[cd]indol-2-ethylene]-ethylene]-2-chloro-1-cyclohexyl-1-enyl]-vinyl)-benzo[cd]indolium tetrafluoroborate (Exciton, IR1014) was used as the starting anthocyanin compound. Otherwise, the procedure was the same as in Synthesis Example 2, yielding 1.79 g of the anthocyanin compound 4 shown in Table 1.

[0173] (1-5) Synthesis Example 5: Synthesis of anthocyanin compound 5 In Synthesis Example 2, 1-butyl-2-(2-[3-(2-[1-butyl-1H-benzo[cd]indol-2-ethylene]ethylene)-2-phenyl-1-cyclopentyl-1-enyl]-vinyl)-benzo[cd]indolium tetrafluoroborate (Few Chemicals, S0813) was used as the starting anthocyanin compound. Otherwise, the procedure was the same as in Synthesis Example 2, and 2.12 g of the anthocyanin compound 5 shown in Table 1 was obtained.

[0174] (1-6) Synthesis Example 6: Synthesis of anthocyanin compound 6 In Synthesis Example 2, 1-butyl-2-[7-(1-butyl-1H-benzo[cd]indol-2-ylidene)-heptane-1,3,5-trienyl]-benzo[cd]indolium hexafluorophosphate (Few Chemicals, S2058) was used as the starting anthocyanin compound. Otherwise, the procedure was the same as in Synthesis Example 2, yielding 1.12 g of the anthocyanin compound 6 shown in Table 1.

[0175] [Table 1]

[0176] (1-7) Synthesis Example 7: Synthesis of Phthalocyanine Compound 1 The phthalocyanine compound 1 shown in Table 2 was synthesized according to the method described in Example 16 of Japanese Patent No. 4278923.

[0177] (1-8) Synthesis Example 8: Synthesis of Phthalocyanine Compound 2 The phthalocyanine compound 2 shown in Table 2 was synthesized according to the method described in Example 2 of Japanese Patent No. 3260317.

[0178] [Table 2]

[0179] (1-9) Synthesis Example 9: Synthesis of Acrylic Resin A To a reaction vessel equipped with a stirrer, temperature sensor, cooling pipe, and nitrogen inlet pipe, add 83.5 parts by weight of methyl methacrylate, 12 parts by weight of 2-hydroxymethyl (meth)acrylate, 88.7 parts by weight of toluene, and 0.05 parts by weight of an antioxidant (manufactured by ADEKA, ADK STAB 2112, registered trademark). While purging the reaction vessel with nitrogen, the temperature is raised to 105°C. At the start of reflux accompanying the heating, add 0.435 parts by weight of a 20% by weight toluene solution of tert-amyl peroxide (manufactured by ARKEMA Yoshitomi, Luperox 570T20, registered trademark) as a polymerization initiator. Then, over 2 hours, add 4.5 parts by weight of styrene and 0.15 parts by weight of n-dodecyl mercaptan, followed by over 4 hours, adding 0.865 parts by weight of a 20% by weight toluene solution of tert-amyl peroxide. During the dropwise addition, the mixture was refluxed at approximately 105°C–110°C for solution polymerization. After the dropwise addition was completed, a further curing process was carried out at the same temperature for 2 hours.

[0180] To the obtained polymer solution, 0.075 parts by weight of stearyl phosphate (manufactured by SC Organic Chemicals, Phoslex A-18) were added, and a cyclization condensation reaction for forming a lactone ring structure was carried out at reflux for 2 hours at approximately 90–110°C. The polymer solution was then passed through a multi-tube heat exchanger heated to 240°C to complete the cyclization condensation reaction. The polymer solution was then fed into a vented twin-screw extruder (L / D = 52) at a processing rate of 100 parts by weight / hour (converted to resin weight). The vented twin-screw extruder has a barrel temperature of 250°C and features one rear vent, four front vents (referred to as the first, second, third, and fourth vents from the upstream side), and a side feeder located between the third and fourth vents. A vane-disc type polymer filter (10 μm filtration accuracy) is installed at the front end. The pressure reduction at the rear exhaust port was set to 798 hPa, the pressure reduction at the first exhaust port was set to 266 hPa, and the pressure reduction at the second to fourth exhaust ports was set to 27 hPa for devolatilization. Ion-exchange water was then introduced at a rate of 1.5 parts by mass per hour from behind the second, third, and fourth exhaust ports.

[0181] After devolatilization, the molten resin composition remaining in the extruder is discharged from the front end of the extruder while being filtered through a polymer filter. It is then passed through a die at the front end of the extruder and introduced into a water tank filled with cooling water for cooling, thereby obtaining a filament of the resin composition. The cooling water is filtered using a 1μm pore size filter (Organo; Micropore Filter 1EU) and maintained at a temperature within the range of 30±10°C. The cooled filament is then fed into a granulator (cutter) to obtain granules of acrylic resin A with a main chain having a lactone ring structure.

[0182] (2) Spectrophotometric determination of anthocyanin and phthalocyanine compounds Chloroform solutions of anthocyanin compounds 1-6 and phthalocyanine compounds 1-2 were prepared, and their transmission spectra were measured in the wavelength range of 300 nm to 1300 nm. The concentrations of the chloroform solutions of the anthocyanin and phthalocyanine compounds were adjusted to achieve a transmittance of 10% (±0.05%) at the maximum absorption wavelength. Transmittance was measured using a spectrophotometer (Shimadzu Corporation, UV-3600) at 1.0 nm intervals. The wavelength at which absorption is greatest (maximum absorption wavelength λmax), the peak width at 50% transmittance for the peak at the maximum absorption wavelength, and the average transmittance in the visible light range of 380 nm to 780 nm were calculated. The results are shown in Table 3. The average transmittance of anthocyanin compounds 1-6 in the wavelength range of 380 nm to 780 nm was greater than 81% when the transmittance at the maximum absorption wavelength was 10%.

[0183] [Table 3]

[0184] (3) Preparation of materials for laser welding (3-1) Preparation Example 1: Preparation of Material 1 for Laser Welding 47.5 parts by weight of chloroform were added to 4.94 parts by weight of polymethyl methacrylate (hereinafter referred to as "PMMA"), and the mixture was stirred at room temperature for 1 hour to obtain resin solution 1. 47.5 parts by weight of chloroform were added to 0.06 parts by weight of anthocyanin compound 4, and the mixture was stirred at room temperature for 1 hour to obtain pigment solution 1. Resin solution 1 and pigment solution 1 were mixed, stirred at room temperature for 2 hours, and then filtered through a 0.45 μm pore size filter (GL Sciences, non-aqueous 13N) to remove foreign matter, yielding laser welding material 1 with a solute concentration of 5.0%.

[0185] (3-2) Preparation Example 2: Preparation of Material 2 for Laser Welding Add 45.0 parts by weight of chloroform to 9.52 parts by weight of PMMA and stir at room temperature for 1 hour to obtain resin solution 2. Add 45.0 parts by weight of chloroform to 0.48 parts by weight of anthocyanin compound 5 and stir at room temperature for 1 hour to obtain pigment solution 2. Mix resin solution 2 and pigment solution 2, stir at room temperature for 2 hours, and then filter through a 0.45 μm pore size filter (GLSciences, non-aqueous 25N) to remove foreign matter, to obtain laser welding material 2 with a solute concentration of 10.0%.

[0186] (3-3) Preparation Example 3: Preparation of Material 3 for Laser Welding Add 47.5 parts by weight of chloroform to 4.94 parts by weight of PMMA and stir at room temperature for 1 hour to obtain resin solution 3. Add 47.5 parts by weight of chloroform to 0.06 parts by weight of anthocyanin compound 5 and stir at room temperature for 1 hour to obtain pigment solution 3. Mix resin solution 3 and pigment solution 3, stir at room temperature for 2 hours, and then filter through a 0.45 μm pore size filter (GLSciences, non-aqueous 13N) to remove foreign matter, obtaining laser welding material 3 with a solute concentration of 5.0%.

[0187] (3-4) Preparation Example 4: Preparation of Material 4 for Laser Welding Add 48.8 parts by weight of chloroform to 2.50 parts by weight of PMMA and stir at room temperature for 1 hour to obtain resin solution 4. Add 48.8 parts by weight of chloroform to 0.003 parts by weight of anthocyanin compound 5 and stir at room temperature for 1 hour to obtain pigment solution 4. Mix resin solution 4 and pigment solution 4, stir at room temperature for 2 hours, and then filter through a 0.45 μm pore size filter (GLSciences, non-aqueous 13N) to remove foreign matter, obtaining laser welding material 4 with a solute concentration of 2.5%.

[0188] (3-5) Preparation Example 5: Preparation of Material 5 for Laser Welding Add 45.0 parts by weight of chloroform to 9.52 parts by weight of acrylic resin A, and stir at room temperature for 1 hour to obtain resin solution 5. Add 45.0 parts by weight of chloroform to 0.48 parts by weight of anthocyanin compound 5, and stir at room temperature for 1 hour to obtain pigment solution 5. Mix resin solution 5 and pigment solution 5, stir at room temperature for 2 hours, and then filter through a 0.45 μm pore size filter (GL Sciences, non-aqueous 25N) to remove foreign matter, to obtain laser welding material 5 with a solute concentration of 10.0%.

[0189] (3-6) Preparation Example 6: Preparation of Material 6 for Laser Welding Add 47.5 parts by weight of chloroform to 4.94 parts by weight of acrylic resin A, and stir at room temperature for 1 hour to obtain resin solution 6. Add 47.5 parts by weight of chloroform to 0.06 parts by weight of anthocyanin compound 5, and stir at room temperature for 1 hour to obtain pigment solution 6. Mix resin solution 6 and pigment solution 6, stir at room temperature for 2 hours, and then filter through a 0.45 μm pore size filter (GL Sciences, non-aqueous 13N) to remove foreign matter, to obtain laser welding material 6 with a solute concentration of 5.0%.

[0190] (3-7) Preparation Example 7: Preparation of Material 7 for Laser Welding Add 48.8 parts by weight of chloroform to 2.50 parts by weight of acrylic resin A, and stir at room temperature for 1 hour to obtain resin solution 7. Add 48.8 parts by weight of chloroform to 0.003 parts by weight of anthocyanin compound 5, and stir at room temperature for 1 hour to obtain pigment solution 7. Mix resin solution 7 and pigment solution 7, stir at room temperature for 2 hours, and then filter through a 0.45 μm pore size filter (GL Sciences, non-aqueous 13N) to remove foreign matter, to obtain laser welding material 7 with a solute concentration of 2.5%.

[0191] (3-8) Preparation Example 8: Preparation of Material 8 for Laser Welding 47.5 parts by mass of chloroform were added to 4.94 parts by mass of a cyclic olefin polymer (hereinafter referred to as "COP"), and the mixture was stirred at room temperature for 1 hour to obtain resin solution 8. 47.5 parts by mass of chloroform were added to 0.06 parts by mass of anthocyanin compound 5, and the mixture was stirred at room temperature for 1 hour to obtain pigment solution 8. Resin solution 8 and pigment solution 8 were mixed, stirred at room temperature for 2 hours, and then filtered through a 0.45 μm pore size filter (GL Sciences, non-aqueous 13N) to remove foreign matter, yielding a laser welding material 8 with a solute concentration of 5.0%.

[0192] (3-9) Preparation Example 9: Preparation of Material 9 for Laser Welding 49.4 parts by weight of cyclohexanone were added to 1.25 parts by weight of polycarbonate (hereinafter referred to as "PC"), the mixture was heated to 75°C and stirred for 1 hour to obtain resin solution 9. 49.4 parts by weight of cyclohexanone were added to 0.002 parts by weight of anthocyanin compound 5, and the mixture was stirred at room temperature for 1 hour to obtain pigment solution 9. Resin solution 9 and pigment solution 9 were mixed and stirred at room temperature for 2 hours. The mixture was then filtered through a 0.45 μm pore size filter (GL Sciences, non-aqueous 13N) to remove impurities, yielding a laser welding material 9 with a solute concentration of 1.25%.

[0193] (3-10) Preparation Example 10: Preparation of Material 10 for Laser Welding Add 45.0 parts by weight of chloroform to 9.30 parts by weight of PMMA, and stir at room temperature for 1 hour to obtain 10 parts by weight of resin solution. 0.48 parts by weight of phthalocyanine compound 1 were added to 45.0 parts by weight of chloroform, and stirred at room temperature for 1 hour to obtain pigment solution 10. Resin solution 10 and pigment solution 10 were mixed and stirred at room temperature for 2 hours. The mixture was then filtered through a 0.45 μm pore size filter (GLSciences, non-aqueous 25N) to remove foreign matter, resulting in laser welding material 10 with a solute concentration of 10.0%.

[0194] (3-11) Preparation Example 11: Preparation of Material 11 for Laser Welding 47.5 parts by mass of chloroform were added to 4.94 parts by mass of PMMA and stirred at room temperature for 1 hour to obtain resin solution 11. 47.5 parts by mass of chloroform were added to 0.06 parts by mass of phthalocyanine compound 2 and stirred at room temperature for 1 hour to obtain pigment solution 11. Resin solution 11 and pigment solution 11 were mixed and stirred at room temperature for 2 hours. The mixture was then filtered through a 0.45 μm pore size filter (GLSciences, non-aqueous 13N) to remove impurities, yielding a laser welding material 11 with a solute concentration of 5.0%.

[0195] (3-12) Preparation Example 12: Preparation of Material 12 for Laser Welding 0.05 parts by mass of anthocyanin compound 5 were mixed into PMMA particles, and melt-mixed for 5 minutes using a Labo Plastomill 4C150 manufactured by Toyo Seiki Co., Ltd. at a screw speed of 150 rpm and a set temperature of 220°C to obtain granular laser welding material 12 composed of PMMA and anthocyanin compound 5.

[0196] (3-13) Preparation Example 13: Preparation of Material 13 for Laser Welding 0.01 parts by mass of anthocyanin compound 5 were mixed into the granules of acrylic resin A obtained in Synthesis Example 9. The mixture was melt-mixed for 3 minutes using a Labo Plastomill 4C150 manufactured by Toyo Seiki Co., Ltd. at a screw speed of 150 rpm and a set temperature of 230°C to obtain granular laser welding material 13 composed of acrylic resin A and anthocyanin compound 5.

[0197] (3-14) Preparation Example 14: Preparation of Material 14 for Laser Welding 0.10 parts by mass of anthocyanin compound 5 were mixed into the granules of acrylic resin A obtained in Synthesis Example 9, and melt-mixed for 3 minutes at a screw speed of 150 rpm and a set temperature of 240°C using a Labo Plastomill 4C150 manufactured by Toyo Seiki Co., Ltd., to obtain granular laser welding material 14 composed of acrylic resin A and anthocyanin compound 5.

[0198] (3-15) Preparation Example 15: Preparation of Material 15 for Laser Welding By replacing PMMA with PC in Preparation Example 12, and otherwise operating in the same manner as in Preparation Example 12, granular laser welding material 15 was obtained.

[0199] (3-16) Preparation Example 16: Preparation of Material 16 for Laser Welding In Preparation Example 12, PMMA was replaced with polystyrene (hereinafter referred to as "PSt"), and the same procedure was followed as in Preparation Example 12 to obtain granular laser welding material 16.

[0200] (3-17) Preparation Example 17: Preparation of Material 17 for Laser Welding In Preparation Example 12, PMMA was replaced with acrylonitrile-styrene copolymer (hereinafter referred to as "AS"), and the same procedure was followed as in Preparation Example 12 to obtain granular laser welding material 17.

[0201] (4) Fabrication of resin substrate for laser welding test (4-1) Manufacturing Example 1: Fabrication of Resin Substrate A1 Polymethyl methacrylate (PMMA) sheets (manufactured by Mitsubishi Chemical, size 70mm×150mm×2mm, hereinafter referred to as "PMMA sheets") were cut into 37.5mm×17mm sizes using an ultrasonic cutter (manufactured by Suzuki, SUW-30CT) to obtain resin substrate A1.

[0202] (4-2) Manufacturing Example 2: Fabrication of Resin Substrate A2 The acrylic resin A granules obtained in Synthesis Example 9 were dried at 100°C for more than 12 hours, and then molded using an injection molding machine (Nissei Resin Co., Ltd., NS40-5A) at a molding temperature of 215°C, a mold temperature of 70°C, and a mold with dimensions of 100mm × 100mm × 2mm to produce an acrylic sheet. This sheet was then cut into 37.5mm × 17mm pieces using an ultrasonic cutter (Suzuki Co., Ltd., SUW-30CT) to obtain resin substrate A2.

[0203] (4-3) Manufacturing Example 3: Fabrication of Resin Substrate A3 The cyclic olefin polymer board (manufactured by ZEON Corporation of Japan, size 70mm×150mm×3mmt, hereinafter referred to as "COP board") was cut into 37.5mm×17mm size using an ultrasonic cutter (manufactured by Suzuki Corporation, SUW-30CT) to obtain resin substrate A3.

[0204] (4-4) Manufacturing Example 4: Fabrication of Resin Substrate A4 The polycarbonate sheet (70mm×150mm×2mm, hereinafter referred to as "PC sheet") was cut into 37.5mm×17mm size using an ultrasonic cutter (manufactured by Suzuki Corporation, SUW-30CT) to obtain resin substrate A4.

[0205] (4-5) Manufacturing Example 5: Fabrication of Resin Substrate B1 The PMMA board used in Manufacturing Example 1 was cut into 70mm × 50mm pieces. 1cc of laser welding material 1 was dropped onto the board, and a film was formed using a spin coater (Mikasa, 1H-D7). The spin coater speed was adjusted to a range of 700rpm to 1600rpm to ensure the light-absorbing layer formed by the coating had a specified transmittance, and the holding time was set to 1 second. The PMMA board with the laser welding material 1 coating was placed in a precision thermostat (Yamato Scientific, DN610I) and heated at 90°C for 30 minutes to dry the coating and form a light-absorbing layer, thus creating a laminate with a light-absorbing layer on the PMMA board. This laminate was then cut into 37.5mm × 17mm pieces using an ultrasonic cutter to obtain resin substrate B1.

[0206] (4-6) Manufacturing Examples 6-10: Fabrication of Resin Substrates B2-B6 Laser welding materials 2 to 6 are used instead of laser welding material 1 in manufacturing example 5. Otherwise, resin substrates B2 to B6 are manufactured in the same manner as in manufacturing example 5.

[0207] (4-7) Manufacturing Example 11: Fabrication of Resin Substrate B7 The acrylic sheet used in Manufacturing Example 2 is used instead of the PMMA sheet in Manufacturing Example 5, and the laser welding material 5 is used instead of the laser welding material 1 in Manufacturing Example 5. Otherwise, the resin substrate B7 is made in the same manner as in Manufacturing Example 5.

[0208] (4-8) Manufacturing Examples 12-13: Fabrication of Resin Substrates B8-B9 Laser welding material 6-7 is used instead of laser welding material 5 in manufacturing example 11. Otherwise, resin substrates B8-B9 are manufactured in the same manner as in manufacturing example 11.

[0209] (4-9) Manufacturing Example 14: Fabrication of Resin Substrate B10 The COP board used in Manufacturing Example 3 is used instead of the PMMA board in Manufacturing Example 5, and the laser welding material 8 is used instead of the laser welding material 1 in Manufacturing Example 5. Otherwise, the resin substrate B10 is made in the same way as in Manufacturing Example 5.

[0210] (4-10) Manufacturing Example 15: Fabrication of Resin Substrate B11 The PC board used in Manufacturing Example 4 is used instead of the PMMA board in Manufacturing Example 5, and the laser welding material 9 is used instead of the laser welding material 1 in Manufacturing Example 5. Otherwise, the resin substrate B11 is made in the same way as in Manufacturing Example 5.

[0211] (4-11) Manufacturing Examples 16-17: Fabrication of Resin Substrates B12-B13 Laser welding material 10-11 is used instead of laser welding material 1 in manufacturing example 5. Otherwise, resin substrates B12-B13 are manufactured in the same manner as in manufacturing example 5.

[0212] (4-12) Manufacturing Example 18: Fabrication of Resin Substrate C1 PMMA granules were dried at 80°C for 5 hours, and then pressed for 2 minutes at 230°C and 20 MPa using a hot press manufactured by Imoto Corporation, thus producing a PMMA sheet with a thickness of 100 μm. This sheet was then cut into 15 mm × 17 mm pieces to obtain resin substrate C1. The thickness of the sheet was calculated by measuring five arbitrary points with a micrometer and taking the average value.

[0213] (4-13) Manufacturing Example 19: Preparation of Resin Substrate C2 The acrylic resin A particles obtained in Synthesis Example 9 were dried at 80°C for 5 hours, and then pressed for 2 minutes at 230°C and 20 MPa using a hot press manufactured by Imoto Corporation, thereby producing an acrylic resin A sheet with a thickness of 300 μm. This sheet was then cut into pieces of 37.5 mm × 17 mm to obtain resin substrate C2.

[0214] (4-14) Manufacturing Example 20: Fabrication of Resin Substrate C3 The acrylic resin A particles obtained in Synthesis Example 9 were dried at 80°C for 5 hours, and then pressed for 2 minutes at 250°C and 20 MPa using a hot press manufactured by Imoto Corporation, thereby producing an acrylic resin A sheet with a thickness of 80 μm. The obtained unstretched sheet was cut into 96 mm × 96 mm pieces and subjected to successive biaxial stretching using a successive biaxial stretching machine X-6S manufactured by Toyo Seiki Corporation at 140°C and a stretching speed of 240 mm / min, in sequence along the longitudinal (MD direction) and transverse (TD direction), so that the stretching ratio was 2 times. The obtained stretched sheet was heat-treated for 1 minute and cooled to obtain a sheet with a thickness of 20 μm. It was cut into 15 mm × 17 mm pieces to obtain resin substrate C3.

[0215] (4-15) Manufacturing Example 21: Fabrication of Resin Substrate C4 The PMMA particles in Manufacturing Example 18 were replaced with PC particles. Otherwise, the PC sheet was made in the same manner as in Manufacturing Example 18 and cut into 15mm × 17mm sizes, thereby obtaining resin substrate C4.

[0216] (4-16) Manufacturing Example 22: Fabrication of Resin Substrate C5 The PMMA particles in Manufacturing Example 18 were replaced with PST particles. Otherwise, PST sheets were made in the same manner as in Manufacturing Example 18 and cut into sizes of 15mm × 17mm, thereby obtaining resin substrate C5.

[0217] (4-17) Manufacturing Example 23: Fabrication of Resin Substrate C6 The PMMA particles in Manufacturing Example 18 were replaced with AS particles. Otherwise, AS sheets were made in the same manner as in Manufacturing Example 18 and cut into sizes of 15mm × 17mm, thereby obtaining resin substrate C6.

[0218] (4-18) Manufacturing Example 24: Fabrication of Resin Substrate D1 The granular laser welding material 12 was dried at 80°C for 5 hours, and then pressed for 2 minutes at 230°C and 20MPa using a hot press manufactured by Imoto Corporation, thereby producing an absorbent material sheet with a thickness of 100μm. This sheet was then cut into 15mm × 17mm pieces to obtain the resin substrate D1.

[0219] (4-19) Manufacturing Example 25: Fabrication of Resin Substrate D2 The granular laser welding material 13 was dried at 80°C for 5 hours, and then pressed for 2 minutes at 230°C and 20MPa using a hot press manufactured by Imoto Corporation, thereby producing an absorber material sheet with a thickness of 300μm. This sheet was then cut into 15mm × 17mm pieces to obtain the resin substrate D2.

[0220] (4-20) Manufacturing Example 26: Fabrication of Resin Substrate D3 The granular laser welding material 14 was dried at 80°C for 5 hours, and then pressed for 2 minutes at 250°C and 20MPa using a hot press manufactured by Imoto Corporation, thereby producing a sheet with a thickness of 80μm. The resulting unstretched sheet was cut into 96mm×96mm pieces and then sequentially biaxially stretched at 140°C and a stretching speed of 240mm / min using a successive biaxial stretching machine manufactured by Toyo Seiki Corporation, in both the longitudinal (MD direction) and transverse (TD direction) directions, to achieve a stretching ratio of 2 times. The resulting stretched sheet was heat-treated for 1 minute and then cooled, thereby producing an absorbent material sheet with a thickness of 20μm. This sheet was then cut into 15mm×17mm pieces to obtain the resin substrate D3.

[0221] (4-21) Manufacturing Example 27: Fabrication of Resin Substrate D4 Laser welding material 15 is used instead of laser welding material 12 in manufacturing example 24. Otherwise, the resin substrate D4 is manufactured in the same manner as in manufacturing example 24. The thickness of the resin substrate D4 is 100 μm.

[0222] (4-22) Manufacturing Example 28: Fabrication of Resin Substrate D5 Laser welding material 16 is used instead of laser welding material 12 in manufacturing example 24. Otherwise, the resin substrate D5 is manufactured in the same manner as in manufacturing example 24. The thickness of the resin substrate D5 is 80 μm.

[0223] (4-23) Manufacturing Example 29: Fabrication of Resin Substrate D6 Laser welding material 17 is used instead of laser welding material 12 in manufacturing example 24. Otherwise, the resin substrate D6 is manufactured in the same manner as in manufacturing example 24. The thickness of the resin substrate D6 is 120 μm.

[0224] (5) Evaluation of resin substrate (5-1) Spectrophotometric determination of resin substrate The transmission spectra of resin substrates A1-A4, B1-B13, C1-C6, and D1-D6 prepared in Examples 1-29 were measured at wavelengths from 300 nm to 1300 nm using a spectrophotometer (Shimadzu Corporation, UV-3600). Transmittance was measured at 1.0 nm intervals, and the transmittance at 1070 nm and the average transmittance of visible light in the range of 380 nm to 780 nm were calculated. The results are shown in Tables 4 and 5.

[0225] [Table 4]

[0226] [Table 5]

[0227] (5-2) Transmission spectra of light-absorbing layers B1 to B6 in resin substrates The transmission spectra of the light-absorbing layers in resin substrates B1-B6 are determined by comparing the transmission spectra of resin substrates B1-B6 with those of resin substrate A1. Similarly, the transmission spectra of the light-absorbing layers in resin substrates B7-B9 are determined by comparing the transmission spectra of resin substrates B7-B9 with those of resin substrate A2. The transmission spectra of the light-absorbing layers in resin substrate B10 are determined by comparing the transmission spectra of resin substrate B10 with those of resin substrate A3. The transmission spectra of the light-absorbing layers in resin substrate B11 are determined by comparing the transmission spectra of resin substrate B11 with those of resin substrate A4. The difference spectral analysis is performed by taking the logarithm (logarithm) of the transmission spectra of resin substrates B1-B11 with light-absorbing layers and the transmission spectra of resin substrates A1-A4 without light-absorbing layers. 10The transmittance of the light-absorbing layer (difference spectrum) is obtained by transforming the light and then performing an exponential transformation on the difference. Specifically, the transmittance of the light-absorbing layer (difference spectrum) is calculated based on the following formula: Transmittance of light-absorbing layer (%) = 10^[log 10 (Transmittance of resin substrates B1 to B11) - log 10 [(Transmittance of resin substrates A1-A4)]×100. The results are shown in... Figures 1-5 .

[0228] (5-3) Transmission spectra of resin substrates D1 to D6 The transmission spectra of resin substrates D1 to D6 were determined, and the results are shown below. Figures 6-10 In addition, the transmission spectra of the pigment components in resin substrates D1 to D6 were determined, and the results are shown below. Figures 11-15 The transmission spectra of the pigment components in resin substrates D1 to D6 were obtained by logarithmic transformation of the transmission spectra of resin substrates D1 to D6 and the transmission spectra of resin substrates C1 to C6 of the same resin and thickness without pigment components. 10 The transmittance (difference spectrum) of the pigment components in resin substrates D1 to D6 is obtained by transforming the difference and then performing an exponential transformation on the difference. Specifically, the transmittance (difference spectrum) of the pigment components in resin substrates D1 to D6 is calculated based on the following formula: Transmittance (%) of pigment components in resin substrates D1 to D6 = 10^[log 10 (Transmittance of resin substrates D1 to D6) - log 10 [Transmittance of resin substrates C1 to C6] × 100.

[0229] (6) Laser welding test method (6-1) Example 1 Resin substrate A1 was overlapped on the side of resin substrate B1 where a light-absorbing layer was formed, and laser light was irradiated from the side of resin substrate A1 to obtain test specimen 1. Laser light was irradiated using a laser device (Panasonic, VL-W1), and the laser wavelength was adjusted within the range of 1070 nm, laser output of 20–70 W, and laser scanning speed of 25–1050 mm / s.

[0230] (6-2) Example 2 The test specimen 2 was prepared in the same manner as in Example 1, except that resin substrate B2 was used instead of resin substrate B1 in Example 1.

[0231] (6-3) Example 3 The test specimen 3 was prepared in the same manner as in Example 1, except that resin substrate B3 was used instead of resin substrate B1 in Example 1.

[0232] (6-4) Example 4 The test specimen 4 was prepared in the same manner as in Example 1, except that resin substrate B4 was used instead of resin substrate B1 in Example 1.

[0233] (6-5) Example 5 The test specimen 5 was prepared in the same manner as in Example 1, except that resin substrate B5 was used instead of resin substrate B1 in Example 1.

[0234] (6-6) Example 6 The test specimen 6 was prepared in the same manner as in Example 1, except that resin substrate B6 was used instead of resin substrate B1 in Example 1.

[0235] (6-7) Example 7 The test specimen 7 was prepared in the same manner as in Example 1, except that resin substrate A2 was used instead of resin substrate A1 in Example 1, and resin substrate B7 was used instead of resin substrate B1 in Example 1.

[0236] (6-8) Example 8 The test specimen 8 was prepared in the same manner as in Example 1, except that resin substrate B8 was used instead of resin substrate B7 in Example 7.

[0237] (6-9) Example 9 The test specimen 9 was prepared in the same manner as in Example 1, except that resin substrate B9 was used instead of resin substrate B7 in Example 7.

[0238] (6-10) Example 10 The test specimen 10 was prepared in the same manner as in Example 1, except that resin substrate A3 was used instead of resin substrate A1 in Example 1, and resin substrate B10 was used instead of resin substrate B1 in Example 1.

[0239] (6-11) Example 11 The test specimen 11 was prepared in the same manner as in Example 1, except that resin substrate A4 was used instead of resin substrate A1 in Example 1, and resin substrate B11 was used instead of resin substrate B1 in Example 1.

[0240] (6-12) Comparative Example 1 The resin substrates A1 are overlapped and irradiated with a laser to obtain test specimen 12.

[0241] (6-13) Comparative Example 2 The resin substrates A2 are overlapped and irradiated with a laser to obtain test specimen 13.

[0242] (6-14) Comparative Example 3 The resin substrates A3 are overlapped and irradiated with a laser to obtain test specimen 14.

[0243] (6-15) Comparative Example 4 The resin substrates A4 are overlapped and irradiated with a laser to obtain test specimen 15.

[0244] (6-16) Comparative Example 5 The test specimen 16 was prepared in the same manner as in Example 1, except that resin substrate B12 was used instead of resin substrate B12.

[0245] (6-17) Comparative Example 6 The test specimen 17 was prepared in the same manner as in Example 1, except that resin substrate B13 was used instead of resin substrate B1 in Example 1.

[0246] (6-18) Example 12 Resin substrate D1 is sandwiched between two resin substrates A1 and overlapped, and then irradiated with a laser to obtain test specimen 18.

[0247] (6-19) Example 13 Resin substrate A2 is superimposed on resin substrate D2, and laser is irradiated from the resin substrate A2 side to obtain test specimen 19.

[0248] (6-20) Example 14 Resin substrate D3 is sandwiched between two resin substrates A2 and overlapped, and then irradiated with a laser to obtain test specimen 20.

[0249] (6-21) Example 15 Resin substrate D4 is sandwiched between two resin substrates A4 and overlapped, and then irradiated with a laser to obtain test specimen 21.

[0250] (6-22) Example 16 The resin substrate D5 was sandwiched between two PST plates and overlapped, and then irradiated with a laser to obtain test specimen 22. The PST plates were made by cutting polystyrene plates (50mm×100mm×2mm) into 25mm×17mm sizes using an ultrasonic cutter (Suzuki, SUW-30CT).

[0251] (6-23) Example 17 The resin substrate D6 was sandwiched between two AS plates and overlapped, and then irradiated with a laser to obtain test specimen 23. The AS plates were made by cutting acrylonitrile-styrene copolymer plates (50mm×100mm×2mm) into 25mm×17mm sizes using an ultrasonic cutter (Suzuki, SUW-30CT).

[0252] (6-24) Comparative Example 7 Resin substrate C1 is sandwiched between two resin substrates A1 and overlapped, and then irradiated with a laser to obtain test specimen 24.

[0253] (6-25) Comparative Example 8 Resin substrate A2 is superimposed on resin substrate C2, and laser is irradiated from the resin substrate A2 side to obtain test specimen 25.

[0254] (6-26) Comparative Example 9 Resin substrate C3 is sandwiched between two resin substrates A2 and overlapped, and then irradiated with a laser to obtain test specimen 26.

[0255] (6-27) Comparative Example 10 Resin substrate C4 is sandwiched between two resin substrates A4 and overlapped, and then irradiated with a laser to obtain test specimen 27.

[0256] (6-28) Comparative Example 11 The resin substrate C5 was sandwiched between and overlapped with the two PSt plates used in Example 16, and then irradiated with a laser to obtain test specimen 28.

[0257] (6-29) Comparative Example 12 The resin substrate C6 was sandwiched between and overlapped with the two AS plates used in Example 17, and then irradiated with a laser to obtain test specimen 29.

[0258] (7) Determination of the weld strength of the test specimen For each test piece 1-29 (37.5mm × 17mm) prepared in Examples 1-17 and Comparative Examples 1-12, the weld strength was measured using a digital force gauge (Imada, ZTS-1000N). In Examples 1-11 and Comparative Examples 5-6, the front ends of resin substrate A and resin substrate B were respectively fixed to a fixture, and a tensile load test (test speed 10mm / min) was performed to determine the weld strength. In Examples 12, 14-17 and Comparative Examples 1-4, 7, 9-12, the front ends of one resin substrate A (or resin board) and the other resin substrate A (or resin board) were respectively fixed to a fixture, and a tensile load test (test speed 10mm / min) was performed to determine the weld strength. In Example 13 and Comparative Example 8, the front ends of resin substrate A and resin substrate C or D were respectively fixed to a fixture, and a tensile load test (test speed 10mm / min) was performed to determine the weld strength. Cases with a weld strength of 10 MPa or higher are rated as "○", while cases with a weld strength of less than 10 MPa or no weld are rated as "×". The results are shown in Tables 6 and 7.

[0259] Tables 6 and 7 also show the average visible light transmittance of the light-absorbing layer of resin substrate B and the pigment component of resin substrate D (absorbing material sheet) in the wavelength range of 380 nm to 780 nm in each embodiment and comparative example. The average visible light transmittance of the light-absorbing layer of resin substrate B is obtained from the transmission spectrum of the light-absorbing layer of resin substrate B calculated in item (5-2), and the average visible light transmittance of the pigment component of resin substrate D is obtained from the transmission spectrum of the pigment component of resin substrate D calculated in item (5-3).

[0260] [Table 6]

[0261] [Table 7]

[0262] Industrial availability The laser welding material of the present invention can be used for laser welding applications.

Claims

1. A material for laser welding, comprising a resin and anthocyanin compound as shown in formula (1), wherein, [Chemical Formula 1] In formula (1), L represents a methine chain with 3 to 9 carbon atoms, wherein each methine group in the chain may independently have substituents, and these substituents may be linked together. A + And A represents the group bonded to the L of the methine chain. X - [This refers to monovalent anions with a pKa below -8.0, representing conjugate acids] The anthocyanin compound has an average transmittance of over 81% in the wavelength range of 380nm to 780nm, with a transmittance of 10% at the wavelength of maximum absorption.

2. The material for laser welding according to claim 1, wherein, The anthocyanin compound has a very high absorption wavelength in the range of 750 nm to 1300 nm.

3. The material for laser welding according to claim 1, wherein, The material used for laser welding also contains a solvent.

4. The material for laser welding according to claim 1, wherein, The resin is a thermoplastic resin.

5. The material for laser welding according to claim 1, wherein, The resin is a (meth)acrylic resin containing structural units with a ring structure in the main chain, wherein the ring structure comprises at least one selected from the group consisting of a lactone ring structure, a glutarimide structure, and a maleimide structure.

6. The material for laser welding according to claim 1, wherein, In the above formula (1), A + And A represents any one of the groups shown in equations (2) to (7) below. [Chemical Formula 2] In formula (2), R 11 Indicates an organic group. R 12 ~R 17 Each can independently represent a hydrogen atom, a halogen atom, or an organic group. * indicates the bonding site with the methylene chain L in formula (1) [Chemical Formula 3] In formula (3), R 21 Indicates an organic group. Ring S represents a hydrocarbon ring with a fused ring structure that may have substituents or a heterocyclic ring with a fused ring structure that may have substituents, and is spirobonded to an adjacent pyrrole ring. Ring T represents an aromatic hydrocarbon ring that may have substituents, an aromatic heterocycle that may have substituents, or a fused ring containing these ring structures that may have substituents. * indicates the bonding site with the methylene chain L in formula (1) [Chemical Formula 4] In equation (4), R 31 Indicates an organic group. R 32 ~R 35 Each can independently represent a hydrogen atom, a halogen atom, or an organic group, or R 32 With R 33 R 33 With R 34 R 34 With R 35 They can be connected to form a ring. Y 1 Represents oxygen atom, sulfur atom, CH=CH or CR 36 R 37 R 36 and R 37 Each represents an organic group. * indicates the bonding site with the methylene chain L in formula (1) [Chemical Formula 5] In formula (5), R 41 ~R 44 Each can independently represent a hydrogen atom, a halogen atom, or an organic group, or R 41 With R 42 R 43 With R 44 They can be connected to form a ring. Y 2 Represents oxygen atom, sulfur atom, or NR. 45 R 45 Indicates an organic group. * indicates the bonding site with the methylene chain L in formula (1) [Chemical Formula 6] In formula (6), R 51 ~R 54 Each can independently represent a hydrogen atom, a halogen atom, or an organic group. Y 3 Represents oxygen atom, sulfur atom, or NR. 55 R 55 Indicates an organic group. * indicates the bonding site with the methylene chain L in formula (1) [Chemical Formula 7] In formula (7), R 61 ~R 63 R 65 ~R 67 Each can independently represent a hydrogen atom, a halogen atom, or an organic group. R 64 Indicates an organic group. * indicates the binding site with the methylene chain L of formula (1).

7. A laminated body having: Substrate; and A light-absorbing layer is disposed on the substrate and is formed of a laser welding material according to any one of claims 1 to 6.

8. The laminate according to claim 7, wherein, The average transmittance of the light-absorbing layer in the wavelength range of 380nm to 780nm is over 80%.

9. An absorbing material formed from a laser welding material according to any one of claims 1 to 6.

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