Curable composition and adhesive

Abstract

This disclosure provides a curable composition containing an olefin compound and a thiol compound. The cured product exhibits high flexibility and is not easily compromised in terms of storage stability. The curable composition disclosed herein contains: a curing component (A), comprising an olefin compound (A1) and a thiol compound (A2); a filler (C); and an anionic polymerization initiator (D). The filler (C) contains polysiloxane powder (C1), and the anionic polymerization initiator (D) contains a microencapsulated curing catalyst (D1).

Description

Technical Field

[0001] This disclosure relates to a curing composition and an adhesive, more specifically to a curing composition containing an olefin compound and a thiol compound and an adhesive containing the curing composition. Prior Technology

[0002] As a composition that can be used as an adhesive, there exist adhesives containing olefin compounds and thiol compounds. The cured product of such an adhesive can be flexible. For example, Patent Document 1 discloses a resin composition containing acrylic resin, thiol compound, latent curing agent, free radical polymerization inhibitor and anionic polymerization inhibitor (see Patent Document 1). Previous technical documents Patent documents

[0003] Patent Document 1: Japanese Patent No. 4976575 Summary of the Invention

[0004] The subject of this disclosure is to provide a curable composition and an adhesive containing the curable composition, wherein the curable composition contains an olefin compound and a thiol compound, and the cured material can have high flexibility and is not easily compromised in terms of storage stability.

[0005] The disclosed curing composition comprises: a curing component (A), which includes an olefin compound (A1) and a thiol compound (A2); a stabilizer (B); a filler (C); and an anionic polymerization initiator (D); wherein the filler (C) comprises polysiloxane powder (C1), and the anionic polymerization initiator (D) comprises a microcapsule-type curing catalyst (D1).

[0006] The adhesive disclosed herein contains the aforementioned curing components. Implementation

[0007] Forms used to implement inventions As a component that can be used as an adhesive, there exist adhesives containing alkene compounds and thiol compounds. The cured form of such an adhesive can be flexible.

[0008] According to the inventor's research, especially in adhesives used in camera modules of smartphones, the hardened material of the adhesive needs to have higher flexibility in order to withstand drop impact tests.

[0009] However, the inventors discovered through their independent research and development of compositions that could be used as adhesives that if polysiloxane powder was mixed into compositions containing olefin and thiol compounds in order to improve flexibility, the preservation stability of the compositions would deteriorate.

[0010] Therefore, in order to provide a curable composition containing olefin and thiol compounds, which can exhibit high flexibility and is not easily compromised in terms of storage stability, the inventors conducted research and development, thereby achieving the present disclosure. However, the reasons for this development are not intended to limit the content of this disclosure.

[0011] The following describes one embodiment of this disclosure. Furthermore, the following embodiment is only one of many embodiments of this disclosure. The following embodiment can be modified according to various design requirements, as long as the purpose of this disclosure is achieved.

[0012] The curable composition of this embodiment is suitable for use as an adhesive, particularly for bonding parts in precision machinery such as camera modules. Furthermore, when used as an adhesive, the curable composition can be used to bond any cured material; that is, its application is not limited to bonding parts in precision machinery such as camera modules. Moreover, the curable composition of this embodiment can also be used for purposes other than adhesives, such as as a sealant for electronic components.

[0013] The curing composition of this embodiment (hereinafter also referred to as composition (X)) contains: a curing component (A), which includes an olefin compound (A1) and a thiol compound (A2); a stabilizer (B); a filler (C); and an anionic polymerization initiator (D); the filler (C) contains polysiloxane powder (C1), and the anionic polymerization initiator (D) contains a microcapsule-type curing catalyst (D1).

[0014] Composition (X) contains a stabilizer (B), thus composition (X) exhibits good storage stability. Furthermore, composition (X) contains polysiloxane powder (C1), thus the cured form of composition (X) possesses high flexibility. Also, although composition (X) contains polysiloxane powder (C1), composition (X) contains a microencapsulated curing catalyst (D1), therefore, the storage stability of composition (X) is not easily compromised.

[0015] The reasons why polysiloxane powder (C1) reduces the storage stability of composition (X) and why microencapsulated curing catalyst (D1) is less likely to cause a decrease in storage stability due to polysiloxane powder (C1) are not fully understood, but the following can be speculated. However, the reasons given below do not limit the composition and function of composition (X) in this embodiment. When compositions containing olefin compounds and thiols contain polysiloxane powder (C1) and latent curing catalysts such as amine adduct-based latent curing catalysts, it is expected that the storage stability of the composition will be improved by the latent curing catalyst, but in reality, the storage stability of the composition is not sufficiently improved. We hypothesize that this is because the polysiloxane powder (C1) has a very low pH, so not only the thiol compound (A2), but also the polysiloxane powder (C1) undergoes deprotonation via latent curing catalysts such as amine adduct-based latent curing catalysts, thus becoming more readily reactable with the alkene compound (A1). As a result, the reaction continues even at room temperature, leading to thickening. In contrast, in this embodiment, composition (X) contains a microencapsulated curing catalyst (D1). The activity of the microencapsulated curing catalyst (D1) is not easily affected by the pH of the polysiloxane powder (C1), therefore we hypothesize that the storage stability of composition (X) is not easily compromised by the polysiloxane powder (C1). Furthermore, the pH of the polysiloxane powder (C1) was determined by the following method: 10g of polysiloxane powder (C1) was mixed with 100g of deionized water, stirred, and then placed in a constant temperature chamber at 95°C for 15 hours. After cooling to room temperature, the filtrate obtained by filtering with filter paper was used as the test liquid, and the pH meter electrode was immersed in the test liquid at 25°C for measurement. In this embodiment, especially when the pH of the polysiloxane powder (C1) is 5.5 or higher and 7.5 or lower, the storage stability caused by the polysiloxane powder (C1) is less likely to decrease.

[0016] The detailed contents of the components (X) are described.

[0017] Alkene (A1) and thiol (A2) are reactive hardening components that can harden the composition (X).

[0018] The olefin compound (A1) contains, for example, a compound having at least one of an acrylonitrile and a methacrylonitrile (hereinafter referred to as an acrylic compound) and a compound having a vinyl group (hereinafter referred to as a vinyl compound).

[0019] The acrylic compound contains, for example, at least one selected from the group consisting of trimethylolpropane triacrylate, 1,6-hexanediol diacrylate, dimethyloltricyclodecane diacrylate, acrylamide, tetrahydrofurfuryl acrylate, 4-hydroxyacrylate, tris(2-acryloxyethyl)triisocyanate, bis(2-acryloxyethyl)triisocyanate, caprolactone-modified tris(2-acryloxyethyl)triisocyanate, eosin-modified diacrylate and eosin-modified triacrylate.

[0020] The vinyl compound contains at least one selected from the group consisting of triallyl isocyanate, allyl glycidyl ether, trimethylolpropane diallyl ether, neopentyl tertrol triallyl ether, etc.

[0021] The olefin compound (A1) preferably contains a compound having a triisocyanate backbone. This improves the adhesion strength of the cured composition (X) when it is applied to an adhesive. The olefin compound (A1) preferably contains at least one compound selected from the group consisting of triisocyanate (2-acryloxyethyl)triisocyanate, bis(2-acryloxyethyl)triisocyanate, caprolactone-modified triisocyanate (2-acryloxyethyl)triisocyanate, EO-modified diacrylate, EO-modified triacrylate, and triallyl isocyanate.

[0022] The compounds that may contain alkene (A1) are not limited to those mentioned above; alkene (A1) may contain various compounds with ethylene-like unsaturated bonds.

[0023] The thiol compound (A2) preferably contains a compound having at least two thiol groups in one molecule. The thiol compound (A1) preferably contains a compound having three or more but no more than six thiol groups in one molecule.

[0024] The thiol compound (A2) contains, for example, an ester of a polyol and a thiol organic acid. The ester contains at least one of a partial ester and a complete ester.

[0025] Polyols include, for example, at least one selected from the group consisting of ethylene glycol, trimethylolpropane, neopentyl tetrol and dinepentyl tetrol.

[0026] Thiol-based organic acids include at least one selected from the group consisting of thiol-aliphatic monocarboxylic acids, esters containing thiol and carboxyl groups obtained by esterification of hydroxy acids with thiol-based organic acids, thiol-aliphatic dicarboxylic acids, and thiol-aromatic monocarboxylic acids. Thiol-aliphatic monocarboxylic acids include, for example, at least one selected from the group consisting of mercaptoacetic acid; mercaptopropionic acid such as 3-mercaptopropionic acid; mercaptobutyric acid such as 3-mercaptobutyric acid and 4-mercaptobutyric acid. The number of carbon atoms in thiol-aliphatic monocarboxylic acids is preferably 2 to 8, more preferably 2 to 6, more preferably 2 to 4, and especially preferably 3. Thiol-aliphatic monocarboxylic acids with 2 to 8 carbon atoms include, for example, at least one selected from the group consisting of mercaptoacetic acid, 3-mercaptopropionic acid, 3-mercaptobutyric acid, and 4-mercaptobutyric acid. Thiol-aliphatic dicarboxylic acids include, for example, at least one selected from the group consisting of mercaptosuccinic acid and 2,3-dimercaptosuccinic acid such as dimercaptosuccinic acid. Thio-aromatic monocarboxylic acids include, for example, thiobenzoic acid such as 4-mercaptobenzoic acid.

[0027] The esters of polyols and thiol organic acids include, for example, at least one selected from the group consisting of trimethylolpropane bis(thiolacetate), trimethylolpropane bis(3-thiolpropionate), trimethylolpropane bis(3-thiolbutyrate), trimethylolpropane bis(4-thiolbutyrate), neopentyltetroxide (thiolacetate), neopentyltetroxide (3-thiolpropionate), neopentyltetroxide (3-thiolbutyrate), neopentyltetroxide (4-thiolbutyrate), dinepentyltetroxide (thiolacetate), dinepentyltetroxide (3-thiolpropionate), dinepentyltetroxide (3-thiolbutyrate), and dinepentyltetroxide (4-thiolbutyrate).

[0028] Examples of polyols and thiol organic acid esters include ethylene glycol bis(thiol acetate), ethylene glycol bis(3-thiol propionate), ethylene glycol bis(3-thiol butyrate), ethylene glycol bis(4-thiol butyrate), trimethylolpropane bis(thiol acetate), trimethylolpropane bis(3-thiol propionate), trimethylolpropane bis(3-thiol butyrate), trimethylolpropane bis(4-thiol butyrate), neopentyltetraethylene tetra(thiol acetate), neopentyltetraethylene tetra(3-thiol propionate), neopentyltetraethylene tetra(3-thiol butyrate), neopentyltetraethylene tetra(4-thiol butyrate), dinepentyltetraethylene hexa(thiol acetate), dinepentyltetraethylene hexa(3-thiol propionate), dinepentyltetraethylene hexa(3-thiol butyrate), dinepentyltetraethylene hexa(4-thiol butyrate), etc. The total esters of polyols and thiol organic acids shall preferably include at least one selected from the group consisting of neopentyl tetrakis(3-mercaptopropionate), neopentyl tetrakis(3-mercaptobutyrate), dinepentyl tetrakis(3-mercaptopropionate) and trimethylolpropane(3-mercaptopropionate).

[0029] Thiol compounds (A2) may also contain, for example, serotonide [(3-mercaptopropoxy)-ethyl]-triisocyanate, 1,3,5-serotonide (3-mercaptobutoxyethyl)-1,3,5-tris(2,4,6(1H,3H,5H)-trione, etc.

[0030] The thiol compound (A2) may also contain compounds other than those described above. For example, the thiol compound (A2) may also contain at least one compound selected from the group consisting of 1,4-butanedithiol, 1,6-hexanedithiol, 1,8-octanedithiol, 1,10-decanedithiol, 3,6-dioxa-1,8-octanedithiol, and bis-2-mercaptoethyl sulfide. The thiol compound (A2) may also contain at least one compound selected from the group consisting of triamcinolone (3-mercaptopropyl) trimiocyanate, 1,3,5-triamcinolone [3-(2-mercaptoethylthio)propyl] trimiocyanate, and 1,3,4,6-tetra(2-mercaptoethyl)ethynylurea.

[0031] The thiol compound (A2) preferably contains a compound having a secondary thiol group. For example, the thiol compound (A2) preferably contains at least one selected from the group consisting of neopentyl tetroxide (3-mercaptobutyrate), 1,4-bis(3-mercaptobutyroxy)butane, 1,3,5-tris(2-(3-hydrothiobutyroxy)ethyl)-1,3,5-tris(2,4,6-trione) and trimethylolpropane(3-mercaptobutyrate). Compounds having a secondary thiol group improve the storage stability of composition (X) compared to compounds having a primary thiol group.

[0032] Relative to the portion of the solid components of composition (X) after removing filler (C), the combined percentage of alkene compound (A1) and thiol compound (A2) should preferably be 70% by mass or more. At this point, composition (X) can exhibit good reactive curing properties. This percentage is preferably 80% by mass or more, and even more preferably 90% by mass or more. Furthermore, this percentage is, for example, 97% by mass or less. Additionally, the solid components are the components of composition (X) after removing volatile components. Volatile components are those that evaporate during the curing process of composition (X) to produce a cured product and do not constitute the cured product; examples include solvents.

[0033] Furthermore, regarding the blending ratio of the alkene compound (A1) to the thiol compound (A2), the thiol compound (A2) / alkene compound (A1) equivalent ratio (i.e., the functional group equivalent ratio of the thiol compound (A2) to the alkene compound (A1)) should preferably be 0.5 or more and 1.5 or less. A blending ratio of 0.7 or more and 1.3 or less is preferred, and a ratio of 0.85 or more and 1.15 or less is even more preferred.

[0034] The reactive curing components in composition (X) may consist solely of an alkene compound (A1) and a thiol compound (A2). Without unduly impairing the effects of this embodiment, composition (X) may also contain reactive curing components other than alkene compounds (A1) and thiol compounds (A2) (hereinafter referred to as component (A3)). When composition (X) contains component (A3), the percentage of component (A3) to alkene compound (A1) should preferably be greater than 0% by mass and less than 70% by mass. A percentage of 50% by mass or less is preferred, and 30% by mass or less is even more preferred. Examples of compounds contained in component (A3) include epoxides, oxetanes, phenols, and amines.

[0035] Composition (X) contains a stabilizer (B) as described above. The stabilizer (B) is a compound that makes the reaction of the reactive components in composition (X), namely the alkene compound (A1) and the thiol compound (A2), less likely to occur. The presence of stabilizer (B) in composition (X) improves its storage stability.

[0036] Stabilizer (B) preferably contains at least one of a free radical polymerization inhibitor and an anionic polymerization inhibitor. This further enhances the storage stability of composition (X). We hypothesize that this is because, during the storage of composition (X), the free radical polymerization inhibitor makes it difficult for the free radical polymerization reaction between the alkene compound (A1) and the thiol compound (A2) and for the free radical polymerization reaction between molecules in the alkene compound (A1) to proceed, and the anionic polymerization inhibitor makes it difficult for the anionic polymerization reaction between the alkene compound (A1) and the thiol compound (A2) to proceed.

[0037] In this embodiment, composition (X) contains an anionic polymerization initiator (D), therefore the stabilizer (B) preferably contains an anionic polymerization inhibitor. In this case, during the storage of composition (X), the anionic polymerization reaction carried out by the anionic polymerization initiator (D) will be inhibited by the anionic polymerization inhibitor, thus further improving the storage stability of composition (X).

[0038] Furthermore, in this embodiment, when the composition (X) contains the radical polymerization initiator (F) described later, the stabilizer (B) preferably contains a radical polymerization inhibitor. In this case, during the storage of the composition (X), the radical polymerization reaction carried out by the radical polymerization initiator (F) will be inhibited by the radical polymerization inhibitor, thus further improving the storage stability of the composition (X). The stabilizer (B) may also contain both anionic polymerization inhibitors and radical polymerization inhibitors simultaneously.

[0039] Free radical polymerization inhibitors may contain at least one compound selected from the group consisting of 4-tertiary butylcatechol, tertiary butylhydroquinone, 1,4-benzoquinone, dibutylhydroxytoluene, 1,1-diphenyl-2-trinitrophenylhydrazine, hydroquinone, hydroquinone monomethyl ether, mequinol, phenothiazine, and N-nitroso-N-phenylhydroxylamine aluminum. Furthermore, compounds that may contain free radical polymerization inhibitors are not limited to those described above.

[0040] The anionic polymerization inhibitor contains at least one of, for example, an organoboronic acid compound and a compound having a phenolic hydroxyl group. The organoboronic acid compound contains at least one borate ester selected from the group consisting of triethyl borate, tributyl borate, and triisopropyl borate. The compound having a phenolic hydroxyl group contains at least one selected from the group consisting of 2,3-dihydroxynaphthyl, 4-methoxy-1-naphthol, pyrogallol, methylhydroquinone, and tributylhydroquinone.

[0041] The percentage of stabilizer (B) relative to the total of alkene compound (A1), thiol compound (A2), stabilizer (B), and anionic polymerization initiator (D) should preferably be 0.01% by mass or more and 1.5% by mass or less. A percentage of 0.01% by mass or more further improves the storage stability of composition (X). A percentage of 1.5% by mass or less has the advantage of not easily impairing the curing properties of composition (X) and maintaining high adhesion strength when composition (X) is cured under appropriate conditions. A percentage of 0.05% by mass or more is preferred, 0.1% by mass or more is even more preferred, and 0.2% by mass or more is particularly preferred. Furthermore, a percentage of 1.2% by mass or less is preferred, 1.0% by mass or less is even more preferred, and 0.7% by mass or less is particularly preferred.

[0042] When the stabilizer (B) contains a free radical polymerization inhibitor, the percentage of the free radical polymerization inhibitor relative to the total of the alkene compound (A1), thiol compound (A2), stabilizer (B), and anionic polymerization initiator (D) should preferably be 0.01% by mass or more and 1.5% by mass or less. A percentage of 0.01% by mass or more can further improve the storage stability of the composition (X). A percentage of 1.5% by mass or less has the advantage of not easily impairing the curing properties of the composition (X) and maintaining high adhesion strength when the composition (X) is cured under appropriate conditions. A percentage of 0.03% by mass or more is preferred, 0.05% by mass or more is even more preferred, and 0.1% by mass or more is particularly preferred. Furthermore, a percentage of 1.0% by mass or less is preferred, 0.5% by mass or less is even more preferred, and 0.25% by mass or less is particularly preferred.

[0043] When the stabilizer (B) contains an anionic polymerization inhibitor, the percentage of the anionic polymerization inhibitor should preferably be 0.01% by mass or more and 1.5% by mass or less, relative to the total of the olefin compound (A1), thiol compound (A2), stabilizer (B), and anionic polymerization initiator (D). A percentage of 0.01% by mass or more further improves the storage stability of the composition (X). A percentage of 1.5% by mass or less has the advantage of not easily impairing the curing properties of the composition (X) and maintaining high adhesion strength when the composition (X) is cured under appropriate conditions. A percentage of 0.05% by mass or more is preferred, 0.1% by mass or more is even more preferred, and 0.15% by mass or more is particularly preferred. Furthermore, a percentage of 1.2% by mass or less is preferred, 1.0% by mass or less is even more preferred, and 0.5% by mass or less is particularly preferred.

[0044] The filler (C) reduces the curing shrinkage of the composition (X) during curing. As mentioned above, the filler (C) contains polysiloxane powder (C1). Therefore, the cured product can have good flexibility. In particular, the elastic modulus of the reaction product of the alkene compound (A1) and the thiol compound (A2) can increase at low temperatures, but if the composition (X) contains polysiloxane powder (C1), the elastic modulus of the cured composition (X) does not easily increase even at low temperatures. Therefore, the cured product can also have a low elastic modulus in a wide temperature range, for example, from -40°C to 120°C.

[0045] Polysiloxane powder (C1) contains, for example, at least one selected from the group consisting of: powder composed of polysiloxane rubber (polysiloxane rubber powder), powder composed of polysiloxane resin (polysiloxane resin powder), and powder having a core composed of polysiloxane rubber and a shell composed of polysiloxane resin (polysiloxane composite powder). Furthermore, the polysiloxane resin is a polysiloxane having a framework primarily composed of three-dimensional siloxane bonds, and the polysiloxane rubber is a polysiloxane having a framework primarily composed of two-dimensional siloxane bonds.

[0046] The polysiloxane powder (C1) preferably contains at least one of polysiloxane resin powder and polysiloxane composite powder. In this case, the cured composition (X) can have a low modulus of elasticity over a wide temperature range.

[0047] The average particle size of the polysiloxane powder (C1) is preferably 0.3 µm or more and 30 µm or less. An average particle size of 0.3 µm or more has the advantage of suppressing excessive viscosity increases in the composition (X). An average particle size of 30 µm or less has the advantage of maintaining high penetration of the composition (X) into narrow spaces. An average particle size of 0.5 µm or more is preferred, and 0.7 µm or more is even more preferred. Furthermore, an average particle size of 20 µm or less is preferred, and 10 µm or less is even more preferred. Additionally, the average particle size is the particle size (d50) at 50% of the cumulative frequency calculated from the particle size distribution on a volume basis determined by laser diffraction.

[0048] The percentage of filler (C) relative to the solid content of composition (X) should preferably be 10% by mass or more and 65% by mass or less. This effectively reduces the hardening shrinkage during the curing of composition (X). A percentage of 15% by mass or more and 50% by mass or less is preferred, and 20% by mass or more and 40% by mass or less is even more desirable.

[0049] The percentage of polysiloxane powder (C1) to filler (C) should preferably be 70% by mass or more and 100% by mass or less. This percentage, as long as it is 70% by mass or more, can particularly improve the flexibility of the hardened material.

[0050] The percentage of polysiloxane powder (C1) relative to the solid content of composition (X) should preferably be 15% by mass or more and 50% by mass or less. A percentage of 15% by mass or more is particularly beneficial for improving the flexibility of the hardened product (X) and reducing hardening shrinkage. Furthermore, a percentage of 50% by mass or less has the advantage of preventing excessive increase in the viscosity of composition (X). A percentage of 20% by mass or more is preferred, 23% by mass or more is even better, and 27% by mass or more is especially preferred. A percentage of 45% by mass or more is preferred, 40% by mass or less is even better, and 35% by mass or less is especially preferred.

[0051] The filler (C) may contain only polysiloxane powder (C1), or it may contain fillers other than polysiloxane powder (C1) (hereinafter also referred to as filler (C2)).

[0052] The filler (C2) may contain inorganic fillers. The filler (C2) may also contain only inorganic fillers. If composition (X) contains inorganic fillers, hardening shrinkage during the hardening process of composition (X) to produce a hardened product becomes less likely to occur. Therefore, composition (X) becomes more suitable for bonding parts in precision machines such as camera modules. The inorganic filler contains, for example, at least one selected from the group consisting of silicon dioxide, aluminum oxide, barium sulfate, talc, clay, mica, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, aluminum borate, barium titanate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, barium zirconate, and calcium zirconate.

[0053] When the filler (C) contains filler (C2) other than polysiloxane powder (C1), the percentage of filler (C2) relative to the solid content of the composition (X) is, for example, greater than 0% by mass and less than 30% by mass.

[0054] As described above, composition (X) contains an anionic polymerization initiator (D), and the anionic polymerization initiator (D) contains a microencapsulated anionic polymerization initiator (microencapsulated curing catalyst (D1)). The microencapsulated curing catalyst (D1) is sometimes considered a type of latent curing catalyst (latent anionic polymerization initiator). The microencapsulated curing catalyst (D1) has a core and a shell covering the core, the core being composed of a catalytically active compound. The shell is, for example, composed of at least one of an organic polymer and an inorganic compound. As a catalytically active compound, the microencapsulated curing catalyst (D1) contains, for example, a microencapsulated imidazole containing imidazoles.

[0055] The percentage of the microencapsulated curing catalyst (D1) relative to the total of alkene compounds (A1) and thiols (A2) should preferably be 1% by mass or more and 35% by mass or less. A percentage of 1% by mass or more enhances the reactivity of the composition (X) during curing. Furthermore, a percentage of 35% by mass or less further improves the storage stability of the composition (X). A percentage of 3% by mass or more is preferred, 5% by mass or more is even better, and 7% by mass or more is particularly preferred. A percentage of 30% by mass or more is preferred, 25% by mass or less is even better, and 20% by mass or less is particularly preferred.

[0056] The anionic polymerization initiator (D) preferably contains only the microencapsulated curing catalyst (D1). Furthermore, without excessively impairing the preservation stability of this embodiment, the anionic polymerization initiator (D) may also contain an anionic polymerization initiator other than the microencapsulated curing catalyst (D1) (hereinafter referred to as curing catalyst (D2)). The curing catalyst (D2) contains, for example, at least one of anionic polymerization initiators other than latent curing catalysts (latent anionic polymerization initiators) and latent curing catalysts other than the microencapsulated curing catalyst (D1). The anionic polymerization initiator other than the latent curing catalyst contains, for example, at least one component selected from the group consisting of imidazoles, cycloamidines, tertiary amines, organophosphorus compounds, tetrasubstituted phosphonium-tetrasubstituted borates, quaternary phosphonium salts having a relative anion other than borates, and tetraphenylboron salts. Latent curing catalysts other than microencapsulated curing catalysts (D1) may contain at least one of solid-dispersed latent curing accelerators and liquid latent curing accelerators, other than microencapsulated curing catalysts (D1). The percentage of anionic polymerization initiator (D) in curing catalyst (D2) should preferably be less than 1% by mass, and less than 0.1% by mass is preferred.

[0057] Composition (X) may also contain carbodiimide compounds (E). In this case, the cured product of composition (X) becomes less prone to degradation even under high temperature and high humidity conditions, thus improving the reliability of the cured product.

[0058] A carbodiimide compound (E) is a compound having a carbodiimide group (-N=C=N-) in its molecule. A carbodiimide compound may contain at least one selected from the group consisting of polycarbodiimides, monocarbodiimides, and cyclic carbodiimides. Polycarbodiimides may contain at least one of aliphatic polycarbodiimides and aromatic polycarbodiimides. Aliphatic polycarbodiimides have a main chain composed of aliphatic hydrocarbons. Aromatic polycarbodiimides have a main chain composed of aromatic hydrocarbons. Monocarbodiimides may contain at least one of aliphatic monocarbodiimides and aromatic monocarbodiimides.

[0059] Single-carbodiimide contains, for example, those selected from N,N'-di-o-tolylcarbodiimide, N,N'-diphenylcarbodiimide, N,N'-di-2,6-dimethylphenylcarbodiimide, N,N'-bis(2,6-diisopropylphenyl)carbodiimide, N,N'-bis(propylphenyl)carbodiimide, N,N'-dioctyldecylcarbodiimide, and N-triyl-N'-cyclohexylcarbodiimide. It is at least one of the group consisting of N,N'-di-2,2-di-tert-butylphenylcarbodiimide, N-triyl-N'-phenylcarbodiimide, N,N'-di-p-nitrophenylcarbodiimide, N,N'-di-p-aminophenylcarbodiimide, N,N'-di-p-hydroxyphenylcarbodiimide, N,N'-dicyclohexylcarbodiimide, and N,N'-di-p-tolylcarbodiimide.

[0060] Polycarbodiimide is, for example, a compound represented by the following formula.

[0061] R 2-(- N=C=NR 1-) mR 3 In the formula, each of the m R1 groups is independently a divalent aromatic or aliphatic group. When R1 is an aromatic group, R1 may be substituted by at least one of the following: an aliphatic substituent, an alicyclic substituent, and an aromatic substituent having at least one carbon atom. These substituents may have heteroatoms, and these substituents may be substituted at at least one ortho position of the aromatic group bonded to the carbodiimine group. R 2 is an alkyl group having 1 to 18 carbon atoms, a cycloalkyl group having 5 to 18 carbon atoms, an aryl group, an aralkyl group having 7 to 18 carbon atoms, -R 4-NH-COS-R 5, -R 4-COOR 5, -R 4-OR 5, -R 4-N(R 5) 2, -R 4-SR 5, -R 4-OH, -R 4-NH 2, -R 4-NHR 5, -R 4-epoxy, -R 4-NCO, -R 4-NHCONHR 5, -R 4-NHCONR 5R 6 or -R 4-NHCOOR 7. R3 is -N=C=N-aryl, -N=C=N-alkyl, -N=C=N-cycloalkyl, -N=C=N-aralkyl, -NCO, -NHCONHR 5, -NHCONHR 5R 6, -NHCOOR 7, -NHCOS-R 5, -COOR 5, -OR 5, epoxy, -N(R 5) 2, -SR 5, -OH, -NH 2, or -NHR 5. R4 is a divalent aromatic or aliphatic group. R5 and R6 are independently alkyl with 1 to 20 carbon atoms, cycloalkyl with 3 to 20 carbon atoms, aralkyl with 7 to 18 carbon atoms, oligo / polyethylene glycol, or oligo / polypropylene glycol. R7 has one of the aforementioned definitions of R5, or is polyester or polyamide. m is an integer of 2 or more.

[0062] Polycarbodiimide includes, for example, at least one selected from the group consisting of poly(4,4'-dicyclohexylmethane carbodiimide), poly(N,N'-di-2,6-diisopropylphenylcarbodiimide), and poly(1,3,5-triisopropylphenyl-2,4-carbodiimide). Examples of commercially available polycarbodiimides include at least one selected from the group consisting of aliphatic polycarbodiimide (Elastostab H-01, manufactured by Nisshinbo Chemical Co., Ltd.) and carbodiimide-modified isocyanate (Carbodilite V-05, manufactured by Nisshinbo Chemical Co., Ltd.).

[0063] A cyclic carbodiimide comprises a carbodiimide group and a group (bonded group) bonded to both nitrogen atoms (the first nitrogen atom and the second nitrogen atom) of that carbodiimide group. The bonded group is, for example, a divalent group selected from aliphatic groups, alicyclic groups, aromatic groups, and groups formed by combinations thereof. The bonded group may also have heteroatoms. Aromatic groups are, for example, selected from the group consisting of aryl groups (5-15 carbon atoms), triaryl groups (5-15 carbon atoms), and tetraaryl groups (5-15 carbon atoms). Aliphatic groups are, for example, selected from the group consisting of alkyl groups (1-20 carbon atoms), triaryl groups (1-20 carbon atoms), and tetraaryl groups (1-20 carbon atoms). Alicyclic groups are, for example, selected from the group consisting of cycloalkyl groups (3-20 carbon atoms), triaryl groups (3-20 carbon atoms), and tetraaryl groups (3-20 carbon atoms).

[0064] The carbodiimide compound (F) preferably contains cyclic carbodiimide. This provides the advantage of being less likely to compromise the storage stability of the composition (X) and further improving the adhesion strength of the hardened material.

[0065] The percentage of carbodiimide compound (E) relative to the total of alkene compound (A1) and thiol compound (A2) should preferably be 1% by mass or more and 20% by mass or less. A percentage of 1% by mass or more will particularly improve the reliability of the cured product. A percentage of 20% by mass or less will maintain the deep curing properties of composition (X) during curing. A percentage of 3% by mass or more is preferred, 5% by mass or more is even better, and 7% by mass or more is especially preferred. Furthermore, a percentage of 15% by mass or less is preferred, 12% by mass or less is even better, and 10% by mass or less is especially preferred.

[0066] Composition (X) may also contain a free radical polymerization initiator (F). The free radical polymerization initiator (F) can impart photocurability to composition (X). In particular, when composition (X) is used as an adhesive, if composition (X) contains a free radical polymerization initiator (F), temporary bonding can be achieved by curing composition (X) to a certain extent by irradiating it with light, followed by full bonding by heating composition (X) to cure it completely.

[0067] The photoradical polymerization initiator (F) contains, for example, at least one compound selected from the group consisting of aromatic ketones, acetyphosphine oxides, aromatic ononium salts, organic peroxides, sulfur compounds (9-thioxanthone compounds, compounds containing phenyl thio groups, etc.), hexaaryl biimidazole compounds, ketoxime esters, borate compounds, azinium compounds, metallocene compounds, active ester compounds, compounds having carbon-halogen bonds, and alkylamine compounds.

[0068] The percentage of the free radical polymerization initiator (F) relative to the total of the alkene compound (A1) and the thiol compound (A2) should preferably be 0.05% by mass or more and 2.0% by mass or less. With this percentage being 0.05% by mass or more, sufficient photocurability for temporary bonding can be imparted to the composition (X). Furthermore, if this percentage is 2.0% by mass or less, the composition (X) can be cured to a deeper extent when exposed to light. This percentage is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and especially preferably 0.4% by mass or more. Furthermore, this percentage is preferably 1.5% by mass or less, more preferably 1.0% by mass or less, and especially preferably 0.8% by mass or less.

[0069] Without unduly impairing the effects of this embodiment, the composition (X) may also contain additives other than those described above. The additives include, for example, at least one selected from the group consisting of free radical scavengers, diluents, solvents, pigments, flexibility enhancers, coupling agents, antioxidants, thixotropic enhancers, and dispersants.

[0070] The composition (X) can be modulated by mixing the components of the above composition (X).

[0071] As described above, composition (X) can be used as an adhesive. That is, a hardened material can be obtained by hardening composition (X), and two parts constituting a machine (hereinafter also referred to as the first part and the second part) can be bonded together from the hardened material.

[0072] The hardened material of this embodiment is obtained by hardening the component (X). As described above, the first part and the second part can be joined by the hardened material.

[0073] The machine of this embodiment includes a first part, a second part, and a hardened material, wherein the hardened material is located between the first part and the second part and connects the first part and the second part. The hardened material is obtained by hardening the component (X). As described above, the machine is, for example, a precision machine such as a camera module, but is not limited thereto. For example, the machine may include electronic components such as semiconductor elements, integrated circuits, large-scale integrated circuits, transistors, thyristors, diodes, and capacitors. When the machine is a camera module, the connection between the first part and the second part is, in other words, the connection between the constituent components of the camera module. Examples of the connection between the first part and the second part include the bonding of a substrate to a camera housing and the bonding of a lens unit to a camera housing. However, the first part and the second part are not limited to these examples.

[0074] The materials of the first and second parts are, for example, resins such as liquid crystal polymers, resins such as polycarbonate, resins such as polyester, metals such as nickel and copper, ceramics, resins such as polyimide, glass, or other various substrate materials, but are not limited to these.

[0075] A method for joining a first part and a second part using a component (X) and a method for manufacturing a machine having a first part, a second part and a hardened material are described.

[0076] The component (X) is positioned between the first part and the second part. In this state, the component (X) is hardened by heating to create a hardened material. The hardened material is then used to bond the first part and the second part.

[0077] When composition (X) contains a photopolymerization initiator (H), and composition (X) is positioned between the first and second parts, before heating, composition (X) is hardened to a certain extent by irradiating it with light. This allows the first and second parts to be temporarily joined. The wavelength of the light irradiating composition (X) can be appropriately selected depending on the type of photopolymerization initiator (H) in composition (X). This light can be, for example, ultraviolet light. By temporarily joining the first and second parts in this way, alignment accuracy can be easily improved by appropriately adjusting the relative positions of the first and second parts.

[0078] The conditions for heating composition (X) are appropriately set in a manner that allows composition (X) to harden sufficiently. For example, the heating conditions are a heating temperature of 80°C or higher and 120°C or lower, and a heating time of 30 minutes or higher and 120 minutes or lower.

[0079] (Summarize) The curing composition of the first state sample contains: a curing component (A), which comprises an olefin compound (A1) and a thiol compound (A2); a stabilizer (B); a filler (C); and an anionic polymerization initiator (D). The filler (C) contains polysiloxane powder (C1). The anionic polymerization initiator (D) contains a microencapsulated curing catalyst (D1).

[0080] Based on this sample, a curable composition containing an alkene compound (A1) and a thiol compound (A2) can be provided. The cured composition can have high flexibility and is not easily compromised in terms of storage stability.

[0081] In the second state sample, in the first state sample, the functional group equivalent ratio of the thiol compound (A2) to the alkene compound (A1) is 0.5 or more and 1.5 or less.

[0082] Based on this state, the hardening component can have good reactivity.

[0083] In the third state sample, in the first or second state sample, the percentage of filler (C) relative to the solid content of the hardening composition is 10% by mass or more and 65% by mass or less.

[0084] Based on this pattern, the hardening shrinkage during the hardening of hardening components can be effectively reduced.

[0085] In the fourth state sample, in the third state sample, the percentage of polysiloxane powder (C1) relative to filler (C) is 70% by mass or more and 100% by mass or less.

[0086] According to this pattern, the flexibility of the hardened material of the hardened component can be improved.

[0087] In the fifth state, in any of the first to fourth states, the stabilizer (B) contains an anionic polymerization inhibitor.

[0088] In the sixth state sample, and in the fifth state sample, the anionic polymerization inhibitor contains an organoboronic acid compound.

[0089] In the seventh state, the curing component in any of the first to sixth states further contains a free radical polymerization initiator (F).

[0090] In the eighth state sample, and in the seventh state sample, the stabilizer (B) contains a free radical polymerization inhibitor.

[0091] In the ninth state, the curing component further contains a carbodiimide compound (E) in any of the first to eighth states.

[0092] According to this pattern, the hardened material of the hardening component becomes less prone to deterioration even under high temperature and high humidity, which can improve the reliability of the hardened material.

[0093] In the tenth state sample, in any of the first to ninth states sample, the total percentage of alkene compound (A1) and thiol compound (A2) is 70% by mass or more relative to the portion after removing the aforementioned filler (C) from the solid component of the hardening composition.

[0094] Based on this state, the hardening component can have good reactivity.

[0095] In the eleventh state sample, in any of the first to tenth states sample, the polysiloxane powder (C1) contains at least one of polysiloxane composite powder and polysiloxane resin powder.

[0096] According to this pattern, the hardened component of the hardening composition can have a low modulus of elasticity over a wide temperature range.

[0097] The adhesive of the twelfth state contains a curing component of any one of the first to eleventh states.

[0098] Based on this sample, an adhesive containing a curing component can be provided, the curing component containing olefin and thiol compounds, the cured material can have high flexibility and is not easily compromised in terms of storage stability.

[0099] [Example] The following presents more specific embodiments of this embodiment. However, this embodiment is not limited to the embodiments described below.

[0100] 1. Modulation of components The composition was prepared by mixing the raw materials shown in Tables 1 to 3. The details of the raw materials shown in Tables 1 to 3 are as follows. -Alkene compound #1: Isocyanuric acid EO-modified di and triacrylates. Manufactured by Dong-A Synthetic Co., Ltd. ARONIX M-313. -Alkene compound #2: Trimethylolpropane triacrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd., product name Viscoat #295. - Thiol compound #1: Neopentyl tetraethylene glycol tetra(3-mercaptobutyrate). Manufactured by Showa Denko Co., Ltd. Product name: Karenz MTPE1 (registered trademark). -Thiol compound #2: 1,3,5-Tris(2-(3-hydrothiobutyrooxy)ethyl)-1,3,5-tris(2,4,6-trione). Manufactured by Showa Denko Co., Ltd. Product name: Karenz MTNR1 (registered trademark). -Thiol compound #3: 1,3,4,6-Tetra(3-mercaptopropyl)acetyleneurea. Manufactured by Shikoku Chemical Industry Co., Ltd. Product name: C3TS-G. - Epoxy compound: Liquid bisphenol A type epoxy resin. Manufactured by Nippon Steel Chemical & Material Co., Ltd. Product name: YD-8125. - Hardening catalyst #1: Microencapsulated imidazole, manufactured by Asahi Kasei E-Materials Co., Ltd., product name NOVACURE HXA9322HP. - Hardening catalyst #2: Microencapsulated imidazole, manufactured by Asahi Kasei E-Materials Co., Ltd., product name NOVACURE HX3722. - Hardening Catalyst #3: A non-microencapsulated modified amine compound that is solid at room temperature. Manufactured by T&K TOKA Corporation. Product name: Fujicure FXR-1121. - Hardening Catalyst #4: A latent hardening catalyst based on a non-microencapsulated amine adduct system. Manufactured by Ajinomoto Fine-Techno Co., Ltd. AJICURE PN-40J. - Photopolymerization initiator #1: 1-Hydroxycyclohexyl-phenyl ketone, manufactured by IGM Resins BV, product name Omnirad 184. - Photopolymerization initiator #2: 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, manufactured by IGM Resins BV, product name Omnirad TPO G. - Stabilizer #1: Free radical polymerization inhibitor. N-Nitrosamino-N-phenylhydroxylamine aluminum. Manufactured by Fujifilm FILM & Koukou Pure Chemicals Co., Ltd. Q-1301. - Stabilizer #2: Anionic polymerization inhibitor. Tributyl borate. - Polysilicon oxide powder #1: Polysilicon oxide composite powder. Manufactured by Shin-Etsu Chemical Industry Co., Ltd. Product name: KMP-605. Average particle size: 2µm. pH: 3.9. - Polysiloxane Powder #2: Polysiloxane resin powder. Manufactured by Shin-Etsu Chemical Industry Co., Ltd. Product name: KMP-706. Average particle size: 2µm. pH: 6.1. -Inorganic filler #1: Silicon dioxide. Manufactured by Admatechs Corporation. Product name: SE-5050. -Inorganic filler #2: Calcium carbonate. Manufactured by Sankyo Fine Powder Co., Ltd. Product name: Escalon #200. - Carbodiimide compound: Cyclic carbodiimide, manufactured by Teijin Corporation, product number TCC-FP20M.

[0101] 2. Evaluation Test (1) Preservation stability The composition was placed in a light-proof container, and the viscosity at 25°C was measured using a type B viscometer at 20 rpm. Viscosity measurements were performed continuously, and the period required for the viscosity at 25°C to become 2.0 times the initial value was defined as the indicator of storage stability.

[0102] (2) Next, strength #1 A composition was coated onto an substrate made of a liquid crystal polymer (product name E463i, manufactured by Polyplastics) to create a coating film with a diameter of 5 mm and a thickness of 0.5 mm. The coating film was then irradiated with ultraviolet light with a peak wavelength of 365 nm under a cumulative irradiance of 500 mJ / cm². The shear bond strength of the composition to the substrate was then measured using a shear tester.

[0103] If the adhesion strength measured is 0.3 MPa or higher, it can be determined that the composition is suitable for temporarily bonding two components together.

[0104] (3) Next, strength #2 A coating with a diameter of 5 mm and a thickness of 0.5 mm was prepared by coating a substrate made of a liquid crystal polymer (product name E463i, manufactured by Polyplastics). The coating was irradiated with ultraviolet light with a peak wavelength of 365 nm under a cumulative irradiance of 500 mJ / cm², and then thermocured at 80°C for 1 hour to obtain a cured product. The shear adhesion strength of the cured product to the substrate was measured using a shear tester.

[0105] (4) Shrinkage rate A polyethylene terephthalate (PET) release film was placed on a glass plate, and a polysiloxane (PE) spacer with an open space of 5 mm × 150 mm (viewed from above) and a thickness of 0.5 mm was placed on the release film. After filling the spacer with the composition, the PET release film was placed on the upper surface of the spacer, and the glass plate was placed on the release film. Under a cumulative irradiance of 500 mJ / cm², ultraviolet light with a peak wavelength of 365 nm was irradiated onto the composition within the space from above the upper glass plate. The composition was then heated at 80°C for 1 hour to thermocure it, thus producing a cured product. The shrinkage rate was calculated from the specific gravity of the composition and the specific gravity of the cured product according to JIS K5600.

[0106] (5) Modulus of elasticity (stored modulus of elasticity) A polyethylene terephthalate (PET) release film was placed on a glass plate, and a polysiloxane (PE) spacer with an open space of 5 mm × 50 mm (viewed from above) and a thickness of 0.5 mm was placed on the release film. After filling the spacer with the composition, the PET release film was placed on the upper surface of the spacer, and the glass plate was placed on the release film. Under a cumulative light intensity of 500 mJ / cm², ultraviolet light with a peak wavelength of 365 nm was irradiated onto the composition in the space from above the upper glass plate. Then, the composition was heated at 80°C for 1 hour to produce a hardened product. The hardened product was subjected to a dynamic viscoelasticity (DMA) tensile test according to JIS K7244-4. The dynamic viscoelasticity (DMA) test was conducted using a Hitachi High-Tech Science DMA7100 measuring device at a frequency of 1.0 Hz and a heating rate of 10°C / min. The results show the maximum value of the elastic modulus (storage elastic modulus) of the hardened material in the range of -60°C to 260°C.

[0107] The results are shown in Tables 1 to 3 below.

[0108] [Table 1]

[0109] [Table 2]

[0110] [Table 3]

[0111] As can be clearly seen from the above results, in Examples 1 to 11, which prepared compositions containing olefin compounds, thiols, polysiloxane powder, and microcapsule-type curing catalysts, the compositions exhibited high storage stability and a reduced elastic modulus of the cured material. In Examples 7 to 11, where carbodiimide compounds were incorporated into the compositions, a tendency was observed to result in higher adhesion strength evaluations after heating.

[0112] On the other hand, in Comparative Examples 1 and 2, where the composition did not contain microencapsulated curing catalysts but instead contained latent curing catalysts, the elastic modulus of the cured product was low, but the storage stability was also low. In Comparative Example 3, where the composition did not contain stabilizers, the storage stability of the composition was also low. Furthermore, in Comparative Example 4, where the composition did not contain polysiloxane powder, the storage stability of the composition was high, but the elastic modulus of the cured product was low, and since the composition did not contain fillers other than polysiloxane powder, the shrinkage rate during curing was high. In Comparative Examples 5 and 6, where the composition did not contain polysiloxane powder but instead contained inorganic fillers, the elastic modulus of the cured product was higher.

[0113] Furthermore, in Comparative Examples 7 and 8, which were mixed with epoxy compounds instead of olefin compounds, no difference was observed in the evaluation of storage stability between Comparative Example 7, which was mixed with microencapsulated curing catalyst and polysiloxane powder, and Comparative Example 8, which was mixed with polysiloxane powder instead of microencapsulated curing catalyst. Therefore, it is clear that the problem of reduced storage stability caused by the mixing of polysiloxane powder is a problem unique to the use of olefin compounds and thiol compounds, and this embodiment can solve this unique problem.

Claims

1. A curing composition comprising: a curing component (A) comprising an olefin compound (A1) and a thiol compound (A2); a stabilizer (B); a filler (C); and an anionic polymerization initiator (D); wherein the filler (C) comprises polysiloxane powder (C1), and the anionic polymerization initiator (D) comprises a microencapsulated curing catalyst (D1).

2. The curing composition of claim 1, wherein the functional group equivalent ratio of the aforementioned thiol compound (A2) to the aforementioned alkene compound (A1) is 0.5 or more and 1.5 or less.

3. The curing composition as claimed in claim 1, wherein the percentage of the filler (C) relative to the solid content of the aforementioned curing composition is 10% by mass or more and 65% by mass or less.

4. The curable composition as claimed in claim 3, wherein the percentage of the aforementioned polysiloxane powder (C1) relative to the aforementioned filler (C) is 70% by mass or more and 100% by mass or less.

5. The curing composition of claim 1, wherein the aforementioned stabilizer (B) contains an anionic polymerization inhibitor.

6. The curing composition as claimed in claim 5, wherein the aforementioned anionic polymerization inhibitor contains an organoboronic acid compound.

7. The curing composition of claim 1 further contains a free radical polymerization initiator (F).

8. The curing composition of claim 7, wherein the aforementioned stabilizer (B) contains a free radical polymerization inhibitor.

9. The curing composition of claim 1 further contains a carbodiimide compound (E).

10. The curing composition of any one of claims 1 to 9, wherein the total percentage of the aforementioned alkene compound (A1) and the aforementioned thiol compound (A2) is 70% by mass or more relative to the portion of the solid component from which the aforementioned filler (C) is removed.

11. The curable composition of any one of claims 1 to 9, wherein the aforementioned polysiloxane powder (C1) contains at least one of polysiloxane composite powder and polysiloxane resin powder.

12. An adhesive comprising a curing composition as claimed in any one of claims 1 to 9.