Method for manufacturing structure

Abstract

Disclosed is a method for manufacturing a structure. The method for manufacturing a structure includes: a first step of preparing a first structure provided with a first adherend, a second adherend, and an adhesion portion for adhering the first adherend and the second adherend to each other, the adhesive part contains a cured product of a curable composition containing a compound A having two or more thiol groups, a compound B having two or more functional groups capable of reacting with thiol groups, and a photo-radical initiator, and at least one of the compound A and the compound B has a disulfide bond in the molecule; and a second step for obtaining a second structure by heating the first structure and volatilizing at least a portion of the photo-radical initiator contained in the bonded portion.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a structure. Background Art

[0002] Photo-softenable compositions that can be softened (melted) by light irradiation are used for various purposes. For example, Patent Document 1 discloses an image forming apparatus including a recording member having a resin layer formed of a photo-softenable composition.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Patent Laid-Open No. 11-190883 Summary of the Invention

[0006] Technical Problem to be Solved by the Invention

[0007] Regarding a composition that exhibits photo-softening properties, for example, after assembling each component to manufacture a structure, it is expected to be used as an adhesive that can repair each component by light irradiation. On the other hand, in an adhesive portion containing such an adhesive (composition), when repair is required, photo-softening properties (photo-melting properties) are exhibited, and when repair is not required, it is required to be able to suppress the manifestation of photo-softening properties (photo-melting properties) by a simple method.

[0008] Therefore, an object of the present invention is to provide a method for manufacturing a structure in which the manifestation of photo-softening properties can be suppressed by a simple method in an adhesive portion containing a composition that exhibits photo-softening properties.

[0009] Means for Solving the Technical Problem

[0010] The photo-softenable composition contains a photo-softenable (photo-meltable) resin (a resin that is low-molecularized by light irradiation) and a photo-radical initiator. According to research conducted by the present inventors, it was found that the photo-softenable resin exhibits photo-softening properties by light irradiation in the presence of a photo-radical initiator. According to further research by the present inventors, it was found that by heating the photo-softenable composition containing these to volatilize at least a part of the photo-radical initiator, the manifestation of photo-softening properties (photo-melting properties) can be suppressed, and thus the present invention was completed.

[0011] The present invention provides a method for manufacturing the structure described in [1] to [3].[[]]END

[0012] [1] A method for manufacturing a structure, comprising: a first step of preparing a first structure, the first structure including a first adherend, a second adherend, and an adhesive portion that bonds the first adherend and the second adherend to each other, the adhesive portion containing a cured product of a curable composition including a compound A having two or more thiol groups, a compound B having two or more functional groups capable of reacting with the thiol groups, and a photo radical initiator, and at least one of the compound A and the compound B having a disulfide bond in the molecule; and a second step of heating the first structure to volatilize at least a part of the photo radical initiator contained in the adhesive portion, thereby obtaining a second structure.

[0013] [2] The method for manufacturing a structure according to [1], wherein the second step is a step of heating the first structure at a temperature higher than the 5% weight loss temperature of the photo radical initiator contained in the adhesive portion.

[0014] [3] The method for manufacturing a structure according to [1] or [2], wherein the 5% weight loss temperature of the photo radical initiator is 180°C or lower.

[0015] Advantages of the Invention

[0016] According to the present invention, there is provided a method for manufacturing a structure capable of suppressing the appearance of photo softening by a simple method in an adhesive portion containing a composition showing photo softening. Brief Description of the Drawings

[0017] Figure 1 is a schematic cross-sectional view showing an embodiment of the first structure, Figure 1 (a), Figure 1 (b) and Figure 1 (c) are views showing various forms of the first structure.

[0018] Figure 2 is a view showing a test sample prepared for adhesive force evaluation. Detailed Description of the Embodiments

[0019] In the present specification, the term "step" includes not only an independent step, but also includes this term even in a case where it cannot be clearly distinguished from other steps as long as the intended function of the step is achieved. Also, the numerical range indicated by "~" represents a range including the numerical values described before and after "~" as the minimum value and the maximum value, respectively.

[0020] Also, in this specification, regarding the content of each component in the curable composition, in the case where there are multiple substances corresponding to each component, unless otherwise specified, it means the total amount of these multiple substances. Also, unless otherwise specified, the exemplified materials can be used alone, or two or more of them can be used in combination.

[0021] Also, within the numerical ranges described stepwise in this specification, the upper limit value or the lower limit value of a certain step's numerical range can be replaced with the upper limit value or the lower limit value of another step's numerical range. Also, in the numerical ranges described in this specification, the upper limit value or the lower limit value of this numerical range can also be replaced with the value shown in the examples. "A or B" means that as long as either A or B is included, both can also be included. In this specification, "(meth)acryloyl" means methacryloyl or acryloyl. Additionally, the "weight average molecular weight" is the polystyrene conversion value obtained by gel permeation chromatography (GPC) using a calibration curve based on standard polystyrene. In this specification, "room temperature" means 25°C.

[0022] In this specification, "photo-softening (photo-melting)" means the property of softening (melting) upon light irradiation. The property of softening (or melting) includes, for example, a decrease in elastic modulus, an increase in loss tangent (tanδ), etc. In this specification, a "softened product (melted product)" means a composition in a state where the elastic modulus is decreased, a composition in a state where the loss tangent (tanδ) is increased, etc., based on the composition before light irradiation (the cured product of the curable composition). A composition showing photo-softening (photo-melting) means a composition that softens (melts) upon light irradiation to give a jelly-like or liquid-like substance.

[0023] [Method for manufacturing a structure]

[0024] The method for manufacturing a structure according to one embodiment includes a first step and a second step.

[0025] <First step>

[0026] This step is a step of preparing a first structure, which includes a first adherend, a second adherend, and an adhesive portion that bonds the first adherend and the second adherend to each other. The adhesive portion contains a reaction product of a compound A having two or more mercapto groups and a compound B having two or more functional groups capable of reacting with the mercapto groups, and a photo-radical initiator. At least one of compound A and compound B has a disulfide bond in the molecule.

[0027] Figure 1 is a schematic cross-sectional view showing one embodiment of the first structure, Figure 1 (a), Figure 1 (b) and Figure 1(c) is a diagram showing various forms of the first structure. The first structure is not particularly limited as long as it includes a first adherend, a second adherend, and an adhesive portion that bonds the first adherend and the second adherend to each other. In Figure 1 in the first structure 10 shown in (a), the main surface 1a of the first adherend 1 and the main surface 2a of the second adherend 2 are bonded to each other via the adhesive portion 3. In Figure 1 in the first structure 20 shown in (b), the main surface 1a of the first adherend 1 and the side surface 2b of the second adherend 2 are bonded to each other via the adhesive portion 3. In Figure 1 in the first structure 30 shown in (c), the side surface 1b of the first adherend 1 and the side surface 2b of the second adherend 2 are bonded to each other via the adhesive portion 3. From the aspect of heating the first structure to volatilize at least a part of the photo radical initiator contained in the adhesive portion, it is preferable that the proportion of the surface of the first structure exposed on the surface of the adhesive portion is large.

[0028] Examples of the first adherend 1 and the second adherend 2 include plastics such as polyolefin resin, polyamide resin, ABS (acrylonitrile-butadiene-styrene) resin, PC (polycarbonate) resin, PET (polyethylene terephthalate) resin, PPS (polyphenylene sulfide) resin, and acrylic resin; inorganic materials such as steel, stainless steel, metals (aluminum, copper, nickel, chromium, etc.) alone or alloys of these metals, glass, and silicon wafers; wood; rubber; etc. Also, as the first adherend 1 and the second adherend 2, materials in which the above plastics and the above inorganic materials are compounded can be cited.

[0029] The thicknesses of the first adherend 1 and the second adherend 2 are not particularly limited and can be 0.05 to 20 mm, 0.1 to 10 mm, or 0.5 to 5 mm.

[0030] The bonding portion 3 contains a cured product of a curable composition containing Compound A, Compound B, and a photo radical initiator. The curing of the curable composition mainly proceeds through the reaction (thermal reaction or photo reaction) between Compound A and Compound B. That is, the bonding portion 3 can contain at least the reaction product (thermal reaction product or photo reaction product) of Compound A and Compound B and the photo radical initiator. The cured product of the curable composition can be a cured product of a thermosetting composition or a cured product of a photocurable composition. In one embodiment, the thermosetting composition can contain Compound A, Compound B, a photo radical initiator, and a curing catalyst as needed. Here, the curing catalyst can be a component that mainly contributes to the reaction between Compound A and Compound B. The photo radical initiator can be a component that mainly contributes to the low molecular weight of the reaction product of Compound A and Compound B. In one embodiment, the photocurable composition can contain Compound A, Compound B, a first photo radical initiator, and a second photo radical initiator. Here, the first photo radical initiator can be a component that mainly contributes to the reaction between Compound A and Compound B. The second photo radical initiator can be a component that mainly contributes to the low molecular weight of the reaction product of Compound A and Compound B.

[0031] (Compound A)

[0032] Compound A is a compound having two or more thiol groups (-SH) in one molecule. The upper limit of the number of thiol groups of Compound A per molecule can be, for example, 10 or less, 8 or less, 6 or less, or 4 or less. Compound A can be a compound having two thiol groups. Compound A can have a disulfide bond in the molecule.

[0033] The molecular weight or weight average molecular weight of Compound A can be 300 or more, 500 or more, or 1000 or more, and can also be 50000 or less, 10000 or less, or 5000 or less.

[0034] When Compound A has a disulfide bond in the molecule, the number of disulfide bonds in one molecule can be, for example, 1 to 1000 or 4 to 50.

[0035] Compound A can be a compound having a linear molecular chain and terminal groups, and having a disulfide bond in the molecular chain (for example, a polymer or an oligomer). In this case, the terminal groups in Compound A can be thiol groups. When Compound A is such a compound, it is easier to form a cured product having excellent photo softening properties. The molecular chain in Compound A can contain a disulfide bond and a polyether chain, or can be composed of a disulfide bond and a polyether chain.

[0036] Compound A can be, for example, Formula (1): HS-(A-S-S) pCompound represented by -A-SH (Compound (1)). In the formula, A represents a polyether chain. When there are multiple A's, they can be the same or different respectively. p represents an integer of 1 or more. p can be, for example, 1 or more or 4 or more, and can also be 1000 or less. Compound A is a compound that extends the chain of Compound (1).

[0037] The polyether chain as A can be, for example, a polyoxyalkylene chain. The polyether chain as A can be, for example, a group represented by -A 1 -O-A 2 -O-A 3 -. A 1 ~A 3 can each independently be an alkylene group, or can be an alkylene group having 1 to 2 carbon atoms (for example, methylene, ethylene). As the polyether chain of A, for example, -CH2CH2-O-CH2-O-CH2CH2- etc. can be cited.

[0038] As commercially available products of Compound A, for example, THIOKOL LP series (dithiols having disulfide bonds, manufactured by TORAYFINE CHEMICALS CO., LTD.) etc. can be cited. Compound A can be used alone as 1 kind, or can be used in combination of 2 kinds or more. Compound A can also be obtained by converting the reactive functional groups (for example, carboxyl group, hydroxyl group) and disulfide bonds of a compound having reactive functional groups at the terminals into thiol groups. As the compound having reactive functional groups and disulfide bonds at the terminals, 3,3'-dithiobispropionic acid, dithiodiethanol, cystamine etc. can be cited.

[0039] Based on the total amount of the curable composition (solid component excluding solvent), the content of Compound A can be 20% by mass or more, 40% by mass or more, or 60% by mass or more, and can also be 95% by mass or less, 92% by mass or less, or 90% by mass or less.

[0040] (Compound B)

[0041] Compound B is a compound having 2 or more functional groups capable of reacting with thiol groups. As the functional groups capable of reacting with thiol groups, for example, isocyanate group; ethylenically unsaturated group (C=C); epoxy group etc. can be cited. Regarding the upper limit of the number of functional groups of Compound B, for each 1 molecule, it can be, for example, 10 or less, 8 or less, 6 or less, or 4 or less. Compound B can be a compound having 2 or 3 functional groups.

[0042] In one embodiment, compound B can be compound B1 having two or more isocyanate groups. For example, compound B1 can include compound B1(1) having two isocyanate groups and compound B1(2) having three or more isocyanate groups. By increasing the content of compound B1(1), the flexibility of the bonding portion 3 can be improved. On the other hand, by increasing the content of compound B1(2), the crosslinking degree can be increased and rigidity can be imparted.

[0043] As compound B1(1), for example, aliphatic diisocyanates such as ethylene diisocyanate, propylene diisocyanate, butylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate; alicyclic diisocyanates such as isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, norbornane diisocyanate, 1,4-isocyanatocyclohexane, 1,3-bis(isocyanatomethyl)-cyclohexane, 1,3-bis(2-isocyanatopropyl-2-yl)-cyclohexane; aromatic diisocyanates such as toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylene diisocyanate, 1,5-naphthalene diisocyanate, etc. can be cited. Among them, compound B1(1) can be an aliphatic diisocyanate or hexamethylene diisocyanate (HDI).

[0044] As compound B1(2), for example, triphenylmethane-4,4',4”-triisocyanate, 1,3,5-triisocyanatobenzene, 1,3,5-tris(isocyanatomethyl)cyclohexane, 1,3,5-tris(isocyanatomethyl)benzene, 2,6-diisocyanatohexanoic acid-2-isocyanatoethyl ester, etc. can be cited. As compound B1(2), for example, trimers of the above-mentioned compound B1(1) can be cited. Among them, compound B1(2) can be a trimer of an aliphatic diisocyanate or a trimer of hexamethylene diisocyanate (HDI).

[0045] In compound B1, the isocyanate group can be protected with a blocking agent. Compounds with isocyanate groups protected by a blocking agent are usually stable at room temperature, but when heated to a temperature above the dissociation temperature of the blocking agent, free isocyanate groups are generated. As the blocking agent, methyl ethyl ketoxime (MEKO, dissociation temperature 130 °C), dimethylpyrazole (DMP, dissociation temperature 110 °C), diethyl malonate (DEM, dissociation temperature 110 °C), active methylene compounds (dissociation temperature 90 °C), etc. can be cited.

[0046] The molecular weight or weight average molecular weight of compound B1 can be 150 or more, and can also be 10,000 or less, 1,000 or less, or 600 or less.

[0047] In one embodiment, compound B may be compound B2 having two or more ethylenically unsaturated groups. Compound B2 may be, for example, a compound having two or more groups selected from the group consisting of allyl (H2C=CH-CH2-), vinyloxy (H2C=CH-O-), and (meth)acryloyl. From the aspect of more excellent photocurability, one form of compound B2 may be compound B2a having two or more groups selected from the group consisting of allyl and vinyloxy.

[0048] Compound B2a may include, for example, compound B2a(1) having two groups selected from the group consisting of allyl and vinyloxy, and compound B2a(2) having three or more groups selected from the group consisting of allyl and vinyloxy.

[0049] As compound B2a(1), for example, compounds having two allyls such as diallyl isophthalate and diallyl terephthalate; compounds having two vinyloxys such as triethylene glycol divinyl ether, 1,4-cyclohexanedimethanol divinyl ether, diethylene glycol divinyl ether, and 1,4-butanediol divinyl ether can be cited.

[0050] As compound B2a(2), for example, triallyl isocyanurate, triallyl trimellitate, triallyl citrate, pentaerythritol tetraallyl ether, etc. can be cited.

[0051] The molecular weight or weight average molecular weight of compound B2a may be 150 or more, and may also be 10,000 or less, 1,000 or less, or 600 or less.

[0052] From the aspect of more excellent thermosetting property, another form of compound B2 may be compound B(2b) having two or more (meth)acryloyl groups. Compound B2b may include, for example, compound B2b(1) having two (meth)acryloyl groups and compound B2b(2) having three or more (meth)acryloyl groups.

[0053] Compound B2b(1) may be, for example, a compound represented by the following formula (x1).

[0054]

[0055] In formula (x1), R 2 represents a hydrogen atom or a methyl group. L 2 represents an alkylene group. When there are a plurality of Rs 2 they may be the same or different respectively. The number of carbon atoms of the alkylene group represented by L 2 may be 2 or more, and may also be 10 or less, 6 or less, or 3 or less. L 2The represented alkylene group can be, for example, an ethylene group (-CH2-CH2-). m represents an integer of 1 or more. m can be 2 or more or 3 or more. The upper limit of m can be, for example, 10 or less, 8 or less, 6 or less, or 5 or less. When there are multiple Ls 2 They can be the same or different from each other.

[0056] As the compound B2b(2), for example, compounds having a trimethylolpropane skeleton and having 3 or more (meth)acryloyl groups, compounds having a pentaerythritol skeleton and having 3 or more (meth)acryloyl groups, compounds having an isocyanurate skeleton and having 3 or more (meth)acryloyl groups, etc. can be cited.

[0057] The molecular weight or weight-average molecular weight of the compound B2b can be 150 or more, 500 or more, or 1000 or more, and can also be 50000 or less, 10000 or less, or 2000 or less.

[0058] In one embodiment, the compound B can be a compound B3 having 2 or more epoxy groups. As the compound B3, epoxy resins can be exemplified.

[0059] As the epoxy resin, for example, novolak type epoxy resins (phenol novolak type epoxy resins, ortho-cresol novolak type epoxy resins, etc.); triphenylmethane type epoxy resins; copolymer type epoxy resins; diphenylmethane type epoxy resins; biphenyl type epoxy resins; stilbene type epoxy resins; glycidyl ester type epoxy resins; glycidylamine type epoxy resins; dicyclopentadiene type epoxy resins; aliphatic type epoxy resins (polyethylene glycol diglycidyl ether, sorbitol polyglycidyl ether, etc.); alicyclic type epoxy resins (vinylcyclohexene dioxide, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 2-(3,4-epoxy)cyclohexyl-5,5-spiro(3,4-epoxy)cyclohexane-m-dioxolane, etc.); p-xylene modified epoxy resins; methyl-p-xylene modified epoxy resins; terpene modified epoxy resins; dicyclopentadiene modified epoxy resins; cyclopentadiene modified epoxy resins; polycyclic aromatic ring modified epoxy resins; naphthalene type epoxy resins; halogenated phenol novolak type epoxy resins; hydroquinone type epoxy resins; trimethylolpropane type epoxy resins; linear aliphatic epoxy resins; aralkyl type epoxy resins, etc.

[0060] The molecular weight or weight-average molecular weight of the compound B3 can be 150 or more, 500 or more, or 1000 or more, and can also be 50000 or less, 10000 or less, or 2000 or less.

[0061] When the compound B has a disulfide bond in the molecule, the number of disulfide bonds in one molecule can be, for example, 1 to 1000 or 4 to 50.

[0062] Based on the total amount of the curable composition (solvent-free solid component), the content of Compound B can be 1% by mass or more, 2% by mass or more, or 3% by mass or more, and can also be 30% by mass or less, 20% by mass or less, or 10% by mass or less.

[0063] The ratio of the total number of moles of thiol groups in Compound A to the total number of moles of functional groups in Compound B can be 0.90 or more or 0.95 or more, and can also be 1.10 or less or 1.05 or less.

[0064] (Photo radical initiator)

[0065] The photo radical initiator is a component that generates radicals upon light irradiation. For example, components used as photo polymerization initiators can be used as the photo radical initiator. Examples of the photo radical initiator include intramolecular cleavage type photo radical polymerization initiators that generate two radicals by photo cleavage of themselves upon light irradiation.

[0066] Examples of the intramolecular cleavage type photo radical initiator include benzyl ketal-based photo radical initiators, α-aminoalkyl phenyl ketone-based photo radical initiators, α-hydroxyalkyl phenyl ketone-based photo radical initiators, hydroxyacetophenone-based photo radical initiators, acylphosphine oxide-based photo radical initiators, and the like.

[0067] The 5% weight loss temperature of the photo radical initiator can be 180 °C or lower. The 5% weight loss temperature refers to the temperature at the point when the mass of the sample decreases by 5% from the initial value in thermogravimetric analysis where the temperature is raised and the mass change of the sample is measured. From the aspect of being able to more sufficiently suppress the manifestation of softening (melting property) based on light irradiation at the bonding part, the 5% weight loss temperature of the photo radical initiator can be 170 °C or lower, 160 °C or lower, 150 °C or lower, 140 °C or lower, 130 °C or lower, 120 °C or lower, or 110 °C or lower. The lower limit of the 5% weight loss temperature of the photo radical initiator can be 80 °C or higher, for example.

[0068] Examples of photo radical initiators with a 5% weight loss temperature of 180 °C or lower include 2-hydroxy-2-methyl-1-phenyl-propan-1-one (Omnirad-1173, 5% weight loss temperature: 101 °C), 1-hydroxy-cyclohexyl-phenyl-ketone (Omnirad-184, 5% weight loss temperature: 155 °C), 2,2-dimethoxy-1,2-diphenylethane-1-one (Omnirad-651, 5% weight loss temperature: 170 °C), etc. Among them, the photo radical initiator can also be 2-hydroxy-2-methyl-1-phenyl-propan-1-one (Omnirad-1173).

[0069] Based on the total amount of the curable composition (solvent-free solid component), the content of the photo-radical initiator can be 1% by mass or more, 3% by mass or more, or 5% by mass or more, and can also be 30% by mass or less, 20% by mass or less, or 15% by mass or less.

[0070] From the aspect of further improving the photo-softening property, the ratio of the number of moles of the photo-radical initiator to the number of moles of compound A (number of moles of photo-radical initiator / number of moles of compound A) can be 0.1 or more, 0.2 or more, or 0.3 or more.

[0071] The thermosetting composition can be a combination of compound A, compound B1 and a photo-radical initiator, a combination of compound A, compound B2 and a photo-radical initiator, or a combination of compound A, compound B3 and a photo-radical initiator. In these combinations, a curing catalyst can be included as needed. Here, the curing catalyst is a component for promoting the reaction between compound A and compound B. Examples of the curing catalyst include amine compounds and phosphorus compounds. Among them, the curing catalyst can be an amine compound.

[0072] The amine compound can be, for example, a secondary amine compound or a tertiary amine compound. Examples of the amine compound include dicyandiamide, trimethylamine, triethylamine, tripropylamine, tributylamine, tri-n-octylamine, dimethylethylamine, dimethylpropylamine, dimethylbutylamine, dimethyl-n-octylamine, 1,4-diazabicyclo[2.2.2]octane, 1,8-diazabicyclo[5.4.0]undec-7-ene, benzyldimethylamine, 4-methyl-N,N-dimethylbenzylamine, 2,4,6-tris(dimethylaminomethyl)phenol, 4-dimethylaminopyridine, etc.

[0073] Based on the total amount of the curable composition (solvent-free solid component), the content of the curing catalyst can be 0.001% by mass or more, 0.01% by mass or more, or 0.015% by mass or more, and can also be 3% by mass or less, 2% by mass or less, or 1% by mass or less.

[0074] The photocurable composition can be a combination of compound A, compound B2, a first photo-radical initiator and a second photo-radical initiator.

[0075] The first photo-radical initiator can be an intramolecular cleavage type photo-radical initiator with an extinction coefficient of 1.0×10 2 mL / (g·cm) or more at the first wavelength, and the second photo-radical initiator can be an intramolecular cleavage type photo-radical initiator with an extinction coefficient less than 1.0×10 2 mL / (g·cm) at the first wavelength. In this specification, the extinction coefficient is a value measured in methanol or acetonitrile.

[0076] When the photocurable composition contains a first photoinitiator and a second photoinitiator, the cured product of the photocurable composition obtained by irradiating with a first light containing light of a first wavelength can be softened (melted) by irradiating with a second light containing light of a wavelength (second wavelength) different from the first wavelength. The second light may contain light of a second wavelength existing on the shorter wavelength side than the first wavelength.

[0077] The first wavelength can be, for example, 447 nm or 405 nm. When the first wavelength is 447 nm, the second wavelength can be 405 nm or 365 nm. When the first wavelength is 405 nm, the second wavelength can be 365 nm.

[0078] The first photoinitiator can be a photoinitiator having a molar extinction coefficient of 1.0×10 2 or more at a wavelength of 447 nm. As such a first photoinitiator, for example, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (Omnirad-819) can be mentioned.

[0079] The first photoinitiator can be a photoinitiator having a molar extinction coefficient of less than 1.0×10 2 at a wavelength of 447 nm and a molar extinction coefficient of 1.0×10 2 or more at a wavelength of 405 nm. As such a first photoinitiator, for example, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one (Omnirad-369), 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (Omnirad-TPO) can be mentioned.

[0080] The second photoinitiator can be a component corresponding to the photoinitiator in the thermosetting composition. The second photoinitiator can be a photoinitiator having a molar extinction coefficient at a wavelength of 447 nm and a molar extinction coefficient at a wavelength of 405 nm of less than 1.0×10 2 and a 5% weight loss temperature of 180 °C or lower. As such a second photoinitiator, for example, 2-hydroxy-2-methyl-1-phenyl-propan-1-one (Omnirad-1173, 5% weight loss temperature: 101 °C), 1-hydroxy-cyclohexyl-phenyl-ketone (Omnirad-184, 5% weight loss temperature: 155 °C), 2,2-dimethoxy-1,2-diphenylethane-1-one (Omnirad-651, 5% weight loss temperature: 170 °C), etc. can be mentioned.

[0081] As a preferred combination of the first photo-radical initiator and the second photo-radical initiator, for example, a combination of Omnirad-819 and Omnirad-1173, a combination of Omnirad-369 and Omnirad-1173, and a combination of Omnirad-TPO and Omnirad-1173 can be cited.

[0082] Based on the total amount of the curable composition (solid components excluding the solvent), the content of the first photo-radical initiator can be 0.1% by mass or more, 0.5% by mass or more, or 1% by mass or more, and can also be 10% by mass or less, 5% by mass or less, or 3% by mass or less.

[0083] Similarly to the content of the above photo-radical initiator, based on the total amount of the curable composition (solid components excluding the solvent), the content of the second photo-radical initiator can be 1% by mass or more, 3% by mass or more, or 5% by mass or more, and can also be 30% by mass or less, 20% by mass or less, or 15% by mass or less.

[0084] The curable composition may further contain Compound A, Compound B, photo-radical initiators (the first photo-radical initiator and the second photo-radical initiator), and components other than the curing catalyst (other components). As other components, for example, plasticizers; tackifiers and other tackiness-imparting agents; antioxidants; colorless dyes; sensitizers; adhesion improvers such as coupling agents; polymerization inhibitors; light stabilizers; defoamers; fillers; chain transfer agents; thixotropy-imparting agents; flame retardants; release agents; surfactants; lubricants; antistatic agents and other additives can be cited. These additives can use known additives. When the curable composition contains other components, based on the total amount of the curable composition, the total content of other components can be 0 to 95% by mass, 0.01 to 50% by mass, or 0.1 to 10% by mass.

[0085] The curable composition can be used as a varnish of the curable composition diluted with a solvent. As the solvent, for example, aromatic hydrocarbons such as toluene, xylene, mesitylene, cumene, and p-cymene; aliphatic hydrocarbons such as hexane and heptane; cycloalkanes such as methylcyclohexane; cyclic ethers such as tetrahydrofuran and 1,4-dioxane; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and 4-hydroxy-4-methyl-2-pentanone; esters such as methyl acetate, ethyl acetate, butyl acetate, methyl lactate, ethyl lactate, and γ-butyrolactone; carbonates such as ethylene carbonate and propylene carbonate; amides such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone (NMP) can be cited. Based on the total amount of the varnish, the content of the solid components in the varnish, that is, the total content other than the solvent in the varnish, can be 10 to 95% by mass, 15 to 70% by mass, or 20 to 50% by mass.

[0086] The curable composition can be prepared, for example, by a method including a step of mixing or kneading the above components. Mixing and kneading can be carried out by appropriately combining common mixers, shearing machines, three-roll mills, ball mills, bead mills and other dispersers.

[0087] In the thermosetting composition, the reaction temperature of Compound A and Compound B can be, for example, 0 to 50 °C, or can be 5 to 45 °C or 10 to 40 °C. The time for maintaining the above reaction temperature can be, for example, 0.1 to 168 hours, or can be 72 hours or less, 24 hours or less, 12 hours or less, 6 hours or less, 4 hours or less, 3 hours or less, or 2 hours or less.

[0088] In the photocurable composition, the light (curing light) when forming a cured product can be, for example, ultraviolet light or visible light. The wavelength of the curing light can be appropriately selected, for example, according to the type of the intramolecular cleavage type photo radical initiator used. The wavelength of the curing light can be, for example, 150 to 830 nm. The curing light can contain, for example, light with a wavelength of 447 nm, a wavelength of 405 nm, or a wavelength of 365 nm.

[0089] For example, a light irradiation device can be used to perform light irradiation under the condition that the irradiation dose is set to 100 mJ / cm 2 or more. The irradiation dose can be appropriately set, for example, according to the wavelength of the curing light. The irradiation dose can be, for example, 1000 mJ / cm 2 or more, 2000 mJ / cm 2 or more, or 3000 mJ / cm 2 or more, and can also be 10000 mJ / cm 2 or less, 7000 mJ / cm 2 or less, or 5000 mJ / cm 2 or less.

[0090] The irradiation dose refers to the product of the illuminance and the irradiation time (seconds). And, as a light source for irradiating ultraviolet light or visible light, for example, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, a metal halide lamp, an LED lamp, etc. can be cited. The light irradiation can be directly carried out on the photocurable composition, or can be carried out through glass or the like.

[0091] In this curable composition, a cured product of the curable composition is formed by carrying out the reaction (thermal reaction or photoreaction) between Compound A and Compound B. The bonding portion 3 can contain at least the reaction product (thermal reaction product or photoreaction product) of Compound A and Compound B, and a photo radical initiator (second photo radical initiator).

[0092] When compound B is compound B1 having two or more isocyanate groups, the reaction product of compound A and compound B1 is formed by the reaction (thiolurethane reaction) between the thiol group in compound A and the isocyanate group in compound B1. That is, the reaction product of compound A and compound B1 has a structure represented by formula (I): *-NH-C(=O)-S-* and a disulfide bond. In formula (I), * represents a bonding site. The disulfide bond may be present in at least one of the main chain and the side chain of the reaction product. From the aspect of further improving the photo-softening property, the disulfide bond may be present in the main chain of the reaction product.

[0093] When compound B is compound B2 having two or more ethylenically unsaturated groups, the reaction product of compound A and compound B2 is formed by the reaction (vinylthiol reaction or Michael addition reaction) between the thiol group in compound A and the ethylenically unsaturated group in compound B2. That is, the reaction product of compound A and compound B has a structure represented by formula (II): *-CH2-CH2-S-* or *-C(=O)-CHR-CH2-S-* and a disulfide bond. In formula (II), * represents a bonding site. The disulfide bond may be present in at least one of the main chain and the side chain of the reaction product. From the aspect of further improving the photo-softening property, the disulfide bond may be present in the main chain of the reaction product.

[0094] When compound B is compound B3 having two or more epoxy groups, the reaction product of compound A and compound B3 is formed by the reaction (ring-opening reaction) between the thiol group in compound A and the epoxy group in compound B3. That is, the reaction product of compound A and compound B has a structure represented by formula (III): *-CH(OH)-CH2-S-* or *-CH(CH2OH)-S-* and a disulfide bond. In formula (III), * represents a bonding site. The disulfide bond may be present in at least one of the main chain and the side chain of the reaction product. From the aspect of further improving the photo-softening property, the disulfide bond may be present in the main chain of the reaction product.

[0095] The thickness of the bonding portion 3 may be 10 to 2000 μm, 30 to 1000 μm, or 50 to 500 μm.

[0096] The cured product of the curable composition contains a reaction product (thermal reaction product or photo reaction product) of Compound A and Compound B that exhibits photo-softening (photo-melting). Therefore, the cured product of the curable composition can be photo-softened (photo-melted) by photo-irradiation in the presence of a photo radical initiator (second photo radical initiator). The mechanism by which the cured product of the curable composition undergoes photo-melting is not necessarily clear, but for example, the following mechanisms can be considered. However, it is not limited to these mechanisms. From the aspect that at least one of Compound A and Compound B has a disulfide bond in the molecule, the cured product of the curable composition contains a compound having a disulfide bond (reaction product of Compound A and Compound B). By photo-irradiating the cured product of the curable composition, the disulfide bond in the cured product is decomposed (cleaved) to generate sulfur radicals. At this time, if a photo radical initiator (intramolecular cleavage type photo radical initiator) is present in the cured product, the sulfur radicals react with the photo radical initiator and the sulfur radicals are capped by the photo radical initiator. Thus, it is considered that the compound having a disulfide bond is low-molecularized and the cured product is photo-softened (photo-melted). As another mechanism, it is also considered that the photo-induced radicals from the photo radical initiator (intramolecular cleavage type photo radical initiator) directly react with the disulfide bond, causing the formation of a photo-induced radical-sulfide bond and the generation of sulfur radicals, and the sulfur radicals react with another photo-induced radical, and the compound itself having a disulfide bond is low-molecularized to soften the photocured product. It can be said that the reaction of disulfide bond cleavage is an irreversible reaction.

[0097] The first structures 10, 20, 30 can be obtained, for example, by a method including the following steps: producing a structure precursor obtained by bonding the first adherend 1 and the second adherend 2 through a curable composition; and in the structure precursor, reacting Compound A and Compound B contained in the curable composition to form a cured product (bonding portion) of the curable composition. The reaction conditions (reaction temperature, holding time, etc.) when Compound A and Compound B undergo a thermal reaction can be the same as those described above. The reaction conditions (wavelength, irradiation amount, etc.) when Compound A and Compound B undergo a photo reaction can be the same as those described above.

[0098] From the aspect that the bonding portion contains the cured product of the curable composition, the first structure exhibits the softening property (melting property) based on photo-irradiation of the bonding portion, and the first adherend and the second adherend can be easily peeled off.

[0099] The light (melting light) for softening (melting) the cured product of the curable composition can be, for example, ultraviolet light or visible light. The wavelength of the melting light can be appropriately selected, for example, according to the type of the photo radical initiator used. The wavelength of the melting light can be, for example, 150 to 830 nm. The melting light can contain, for example, light with a wavelength of 405 nm or a wavelength of 365 nm.

[0100] For example, light irradiation can be performed using a light irradiation device under the condition that the irradiation dose is set to exceed 3000 mJ / cm 2 . The irradiation dose can be appropriately set according to, for example, the wavelength of the melting light. The irradiation dose can be, for example, 15000 mJ / cm 2 or more, 20000 mJ / cm 2 or more, or 25000 mJ / cm 2 or more, and can also be 100000 mJ / cm 2 or less, 50000 mJ / cm 2 or less, or 35000 mJ / cm 2 or less.

[0101] <Second step>

[0102] This step is a step of heating the first structure to volatilize at least a part of the photo radical initiator (second photo radical initiator) contained in the bonding portion, thereby obtaining a second structure. Here, the second structure corresponds to the "structure" in the manufacturing method of the structure of the present embodiment. Thus, a structure (second structure) can be obtained in which the amount of the photo radical initiator contained in the bonding portion is less than the amount of the photo radical initiator contained in the bonding portion of the first structure. The present inventors speculate that in the first structure, by volatilizing at least a part of the photo radical initiator (second photo radical initiator), the amount of the photo radical initiator (second photo radical initiator) required for the manifestation of photo softening (photo melting) is insufficient, and as a result, the manifestation of photo softening (photo melting) can be suppressed.

[0103] The atmosphere gas when heating the first structure is not particularly limited. For example, it can be an air atmosphere gas or an inert gas atmosphere gas such as nitrogen or argon.

[0104] The pressure condition in the atmosphere gas when heating the first structure is not particularly limited. It can be under atmospheric pressure conditions or under reduced pressure (negative pressure) conditions.

[0105] The heating temperature when heating the first structure is not particularly limited and can be arbitrarily set in combination with the properties of the photo radical initiator. The heating temperature can be, for example, a temperature higher than the 5% weight loss temperature of the photo radical initiator contained in the bonding portion. If heating is performed under such temperature conditions, the photo radical initiator can be volatilized more sufficiently. The heating temperature can be a temperature 5°C higher than the 5% weight loss temperature of the photo radical initiator, or can be a temperature 10°C higher than the 5% weight loss temperature of the photo radical initiator. The heating temperature can exceed 110°C, can also be 120°C or higher, and can also be 300°C or lower or 200°C or lower.

[0106] The time for maintaining the above heating temperature can be, for example, 0.1 to 72 hours, or can be more than 0.5 hours, more than 1 hour, more than 1.5 hours, or more than 2 hours, and can also be 36 hours or less, 24 hours or less, 12 hours or less, or 8 hours or less.

[0107] There is no particular limitation on the heating device when heating the first structure, and an oven, a hot plate, etc. can be used. From the aspect of being able to heat the first structure, the heating device can be, for example, an oven capable of temperature control.

[0108] Thus, a structure (second structure) having an adhesive portion in which the manifestation of softening (melting) based on light irradiation is suppressed can be obtained. According to such a structure (second structure), from the aspect that the manifestation of softening (melting) of the adhesive portion based on light irradiation is suppressed, when the adhesive portion is irradiated with light, the first adherend and the second adherend can be made less likely to peel compared to the first structure.

[0109] Examples

[0110] Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to these examples.

[0111] 1-1. Materials to be tested

[0112] · Compound A

[0113] A-1: Polysulfide polymer (THIOKOL LP-55 (manufactured by TORAY FINE CHEMICALS CO., LTD., SH% = 1.8%))

[0114]

[0115] · Compound B

[0116] B1(1)-1: Hexamethylene diisocyanate (Millionate HDI, manufactured by TOSOH CORPORATION, molecular weight 168.2)

[0117] B1(2)-1: 1,3,5-Tris(6-isocyanato-1-yl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione (Desmodur N-3300 (HDI trimer), manufactured by Sumika Covestro Urethane Co., Ltd., molecular weight 504.6)

[0118] · Photo radical initiator

[0119] C-1: 2-Hydroxy-2-methyl-1-phenyl-propan-1-one (Omnirad-1173, manufactured by IGM Resins B.V., 5% weight loss temperature: 101 °C)

[0120] · Curing catalyst

[0121] D-1: Triethylamine (TEA, manufactured by Tokyo Chemical Industry Co., Ltd.)

[0122] 1-2. Preparation of the thermosetting composition

[0123] The test materials were prepared in the composition ratios shown in Table 1 in the following order. First, Compound A and the curing catalyst were prepared in a 30 mL plastic ointment jar. At this time, the amount of Compound A was adjusted so that the content of the curing catalyst was 1 mass% based on the total amount of Compound A and the curing catalyst. Next, the mixture was stirred at 2000 rpm for 1.5 minutes using a planetary mixer (Awatori Rentaro ARE-310, manufactured by THINKY CORPORATION) to obtain Mixture a. Next, the remaining Compound A, Compound B, and the photo radical initiator were prepared in a 30 mL plastic ointment jar, and the mixture was stirred at 2000 rpm for 1.5 minutes using the same planetary mixer to obtain Mixture b. Next, Mixture a and Mixture b were prepared in a 30 mL plastic ointment jar, and the mixture was stirred at 2000 rpm for 1.5 minutes to prepare the thermosetting composition of Production Example 1.

[0124] 1-3. Light irradiation

[0125] A UV irradiation device (manufactured by Panasonic Industrial Devices SUNX Co., Ltd., power supply: AicureUJ30, 365 nm LED lamp head: ANUJ6186) was used for UV irradiation. Regarding the irradiation conditions, an illuminometer UIT-250 (manufactured by Ushio Inc.) and a 365 nm light receiver were used.

[0126] 1-4. Adhesion evaluation

[0127] Two glass slides (S-1112, manufactured by Matsunami Glass Ind., Ltd.) were prepared. As Figure 2 shown, the thermosetting composition of Production Example 1 was sandwiched between two glass slides to be 65 mm in length, 2.0 mm in width, and 100 μm in thickness, and cured at room temperature for 1 week to obtain a plurality of shear test samples (1a).

[0128] For the bonded part of the obtained shear test sample (1a), LED light with a wavelength of 365 nm was irradiated at an illuminance of 1000 mW / cm 2 for 10 seconds, thereby obtaining a shear test sample (1b).

[0129] For the obtained shear test sample (1a), using a small high-temperature test chamber (ST-120, manufactured by ESPEC CORP.), it was heated at 120 °C for 2 hours. For the bonded part of the heated shear test sample (1a), LED light with a wavelength of 365 nm was irradiated at an illuminance of 1000 mW / cm 2 for 10 seconds, thereby obtaining a shear test sample (1c).

[0130] For the obtained shear test samples (1a) to (1c), using an automatic stereoplotter AGS-X manufactured by Shimadzu Corporation, the shear adhesive force was measured at a tensile speed of 10 mm / min in an environment at room temperature (25 °C). The results are shown in Table 1.

[0131] [Table 1]

[0132]

[0133] 2-1. Materials to be tested

[0134] · Compound A

[0135] A-1: Polysulfide polymer (THIOKOL LP-55, manufactured by TORAY FINE CHEMICALS CO., LTD., SH% = 1.8%)

[0136]

[0137] · Compound B

[0138] B2a(1)-1: Diallyl isophthalate (manufactured by Tokyo Chemical Industry Co., Ltd., molecular weight 246.3)

[0139] B2a(2)-1: Triallyl isocyanurate (manufactured by SHINRYO CORPORATION, molecular weight 249.3)

[0140] · First photoinitiator

[0141] C(1)-1: 2,4,6-Trimethylbenzoyl-diphenylphosphine oxide (Omnirad-TPO, manufactured by IGM Resins B.V., 5% weight loss temperature: 253 °C)

[0142] · Second photo radical initiator

[0143] C(2)-1: 2-Hydroxy-2-methyl-1-phenyl-propan-1-one (Omnirad-1173, manufactured by IGM Resins B.V., 5% weight loss temperature: 101 °C)

[0144] 2-2. Preparation of photocurable composition

[0145] The materials to be tested were added to a 100 mL flask at the composition ratios shown in Tables 2 and 3, and using a mechanical stirrer, the components were stirred and dissolved and mixed at 100 °C for 1 hour, thereby preparing the photocurable compositions of Production Examples 2 and 3.

[0146] 2-3. Light irradiation

[0147] In the UV irradiation, a UV irradiation device (manufactured by Panasonic Industrial Devices SUNX Co., Ltd., power supply: AicureUJ30, 405 nm LED head: ANUJ6189, 365 nm LED head: ANUJ6186) was used. Regarding the irradiation conditions, an illuminometer UIT-250 (manufactured by Ushio Inc.) and a 405 nm light receiver and a 365 nm light receiver were used respectively.

[0148] 2-4. Adhesion evaluation

[0149] Two glass slides (S-1112, manufactured by Matsunami Glass Ind., Ltd.) were prepared. As Figure 2 shown, the thermosetting compositions of Production Examples 2 and 3 were respectively sandwiched between two glass slides to have a length of 65 mm, a width of 2.0 mm and a thickness of 100 μm, thereby obtaining each laminate. For the obtained laminate, LED light with a wavelength of 405 nm was irradiated at an illuminance of 2000 mW / cm 2 for 2 seconds, thereby obtaining a plurality of shear test samples (2a), (3a).

[0150] For the bonded portions of the obtained shear test samples (2a), (3a), LED light with a wavelength of 365 nm was irradiated at an illuminance of 1000 mW / cm 2 for 10 seconds, thereby obtaining shear test samples (2b), (3b).

[0151] For the obtained shear test samples (2a) and (3a), they were heated at 120 °C for 2 hours using a small high-temperature test chamber (ST-120, manufactured by ESPEC CORP.). For the bonded parts of the heated shear test samples (2a) and (3a), LED light with a wavelength of 365 nm was irradiated at an illuminance of 1000 mW / cm 2 for 10 seconds, thereby obtaining shear test samples (2c) and (3c).

[0152] For the obtained shear test samples (2a) and (3a), they were heated at 120 °C for 4 hours using a small high-temperature test chamber (ST-120, manufactured by ESPEC CORP.). For the bonded parts of the heated shear test samples (2a) and (3a), LED light with a wavelength of 365 nm was irradiated at an illuminance of 1000 mW / cm 2 for 10 seconds, thereby obtaining shear test samples (2d) and (3d).

[0153] For the obtained shear test sample (3a), it was heated at 120 °C for 6 hours using a small high-temperature test chamber (ST-120, manufactured by ESPEC CORP.). For the bonded part of the heated shear test sample (3a), LED light with a wavelength of 365 nm was irradiated at an illuminance of 1000 mW / cm 2 for 10 seconds, thereby obtaining shear test sample (3e).

[0154] For the obtained shear test samples (2a) to (2d) and (3a) to (3e), the shear adhesive force was measured at a tensile speed of 10 mm / min in an environment of 25 °C using an automatic stereoplotter AGS-X manufactured by Shimadzu Corporation. The results are shown in Tables 2 and 3.

[0155] [Table 2]

[0156]

[0157] [Table 3]

[0158]

[0159] As shown in Table 1, Table 2, and Table 3, the shear test samples (1a), (2a), and (3a) equivalent to the first structure were irradiated with light, and as shown by the results of the shear test samples (1b), (2b), and (3b), the shear adhesion force was significantly reduced. It is considered that this is because the adhesive part was photo-softened (photo-melted). In contrast, the shear test samples (1c), (2c), (2d), (3c), (3d), and (3e) equivalent to the second structure suppressed the reduction of the shear adhesion force. It is considered that this is because at least a part of the photo radical initiator (second photo radical initiator) contained in the adhesive part volatilized. Through the above, it was confirmed that according to the method for manufacturing a structure of the present invention, in an adhesive part containing a composition exhibiting photo-softening properties, the manifestation of photo-softening properties can be suppressed by a simple method.

[0160] Symbol Explanation

[0161] 1 - First adherend, 2 - Second adherend, 3 - Adhesive part, 10, 20, 30 - First structure.

Claims

1. A method for manufacturing a structure, comprising: A first step of preparing a first structure, the first structure including a first adherend, a second adherend, and an adhesive portion that bonds the first adherend and the second adherend to each other, the adhesive portion containing a cured product of a curable composition including a compound A having two or more thiol groups, a compound B having two or more functional groups capable of reacting with the thiol groups, and a photo radical initiator, and at least one of the compound A and the compound B having a disulfide bond in the molecule; and A second step of heating the first structure to volatilize at least a part of the photo radical initiator contained in the adhesive portion, thereby obtaining a second structure.

2. The method for manufacturing a structure according to claim 1, wherein the second step is a step of heating the first structure at a temperature higher than the 5% weight loss temperature of the photo radical initiator contained in the adhesive portion.

3. The method for manufacturing a structure according to claim 1 or 2, wherein the 5% weight loss temperature of the photo radical initiator is 180 °C or lower.

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