Adhesive composition

Abstract

An adhesive composition according to one embodiment of the present invention comprises a first polyfunctional thiol-based compound prepared from a polymerizable composition comprising (a) a polyether having a polyfunctional hydroxyl group bonded to a polyoxyalkylene linker, (b) a compound having two or more isocyanate groups, and (c) a compound having two or more thiol groups, wherein the polyether of (a) comprises three or more hydroxyl groups bonded to a polyoxyalkylene linker.

Description

Technology Field

[0001] The present invention relates to an adhesive composition. Background Technology

[0002] Adhesives used in the assembly of conventional camera modules require low-temperature curing properties to avoid thermal damage caused by high-temperature processing of image sensors and the like. Additionally, fast-curable properties are simultaneously required to improve production efficiency. In this regard, photo-curing or thermal-curing adhesives are widely used as low-temperature fast-curing adhesives.

[0003] However, while photocurable adhesives allow for rapid curing, they have disadvantages such as causing curing deformation due to shrinkage or being unsuitable for bonding areas not exposed to light.

[0004] Thermosetting adhesives are inconvenient to use because the components to be bonded must be secured with a jig or device to maintain the bonding position during the bonding process. Additionally, as viscosity decreases due to the temperature rise, problems such as sagging just before curing or leakage to unintended areas have occurred.

[0005] To address the aforementioned problems, a dual-curing adhesive has recently been proposed that performs temporary fixation by irradiation with light (e.g., ultraviolet or visible light) and then performs main curing by heat. Such a dual-curing adhesive has the advantage of being able to perform uniform main curing without the need for additional devices.

[0006] However, dual-curing adhesives have a problem in that fluidity decreases sharply as the modulus rises after pre-curing by light irradiation. This decrease in fluidity can lead to a lower degree of curing during the main curing process caused by heat, or additional problems may arise where the adhesive absorbs external shocks directly due to the increased modulus, resulting in cracking.

[0007] Accordingly, there is a need for research on adhesives capable of overcoming the aforementioned problems. The problem to be solved

[0008] According to one embodiment of the present invention, an adhesive composition having excellent adhesion and impact resistance can be provided.

[0009] The problems of the present invention are not limited to those described above. A person skilled in the art to which the present invention pertains will have no difficulty understanding additional problems of the present invention from the overall contents of this specification. means of solving the problem

[0010] An adhesive composition according to one embodiment of the present invention comprises a first polyfunctional thiol-based compound prepared from a polymerizable composition comprising (a) a polyether having a polyfunctional hydroxyl group bonded to a polyoxyalkylene linker, (b) a compound having two or more isocyanate groups, and (c) a compound having two or more thiol groups, wherein the polyether of (a) comprises three or more hydroxyl groups bonded to a polyoxyalkylene linker.

[0011] In addition, in the above adhesive composition, the polyether of (a) can be represented by the following chemical formula 1.

[0012] [Chemical Formula 1]

[0013]

[0014] (In the above Chemical Formula 1, R is each independently hydrogen or (C1-C10)alkyl, and x, y, and z are each independently integers from 10 to 100)

[0015] In addition, in the adhesive composition above, the compound of (b) may include a (C3-C10) aliphatic diisocyanate.

[0016] In addition, in the adhesive composition above, the compound of (c) may include a (C1-C15) aliphatic dithiol.

[0017] In addition, in the adhesive composition above, the first polyfunctional thiol-based compound can be represented by the following chemical formula 2.

[0018] [Chemical Formula 2]

[0019]

[0020] (In the above formula 2, R is each independently hydrogen or (C1-C10)alkyl, x, y, and z are each independently integers from 10 to 100, L1 is each independently (C1-C8)alkylene, (C1-C8)alkenylene, or a combination thereof, L2 is each independently (C1-C15)alkylene, (C1-C15)alkenylene, or a combination thereof, and the hydrogens of L1 and L2 may each independently be substituted with one or more substituents selected from halogen, nitro, cyano, (C1-C7)alkyl, and (C1-C7)alkoxy.)

[0021] In addition, in the adhesive composition, the first polyfunctional thiol-based compound may be included in an amount of 7 to 17 weight percent based on the total weight of the adhesive composition.

[0022] In addition, the adhesive composition further comprises a second polyfunctional thiol compound, and the second polyfunctional thiol compound may include one or more selected from the group consisting of tris[2-(3-mercaptopropionyloxy)ethyl]isocyanurate, 1,4-bis(3-mercaptobutyryloxy)butane, 1,3,5-tris(3-mercaptobutyloxyethyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetra(3-mercaptobutylate), pentaerythritol tetra(3-mercaptopropionate), dipentaerythritol hexa(3-mercaptopropionate), and tetraethyleneglycol bis(3-mercaptopropionate).

[0023] In addition, in the adhesive composition, the weight ratio of the first polyfunctional thiol-based compound and the second polyfunctional thiol-based compound may be 1:0.5 to 2.5.

[0024] In addition, the adhesive composition may further include a polyfunctional acrylate-based compound and a photoinitiator.

[0025] In addition, the adhesive composition may further comprise a thermosetting agent comprising a polyfunctional epoxy-containing compound; and a filler.

[0026] In addition, the adhesive composition may be a one-component type.

[0027] A solar cell module according to another embodiment of the present invention comprises: a first substrate; a second substrate; and an adhesive layer provided between the first substrate and the second substrate, comprising a cured product of the adhesive composition. Effects of the invention

[0028] The adhesive composition according to the present invention can provide an adhesive composition having excellent impact resistance and adhesive strength. The adhesive composition according to the present invention can be usefully applied as a material for forming various optical members and optical devices, and in particular, can be usefully applied as an adhesive layer between constituent members such as camera modules where high adhesive strength and impact resistance per unit area are required.

[0029] The various and beneficial advantages and effects of the present invention are not limited to those described above and will be more easily understood in the process of explaining specific embodiments of the present invention. Specific details for implementing the invention

[0030] Preferred embodiments of the present invention are described below. However, embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below.

[0031] In addition, embodiments of the present invention are provided to more fully explain the present invention to those with average knowledge in the relevant technical field.

[0032] In describing the embodiments of the present invention, if it is determined that a detailed description of known technology related to the present invention may unnecessarily obscure the essence of the present invention, such detailed description will be omitted. Furthermore, the terms described below are defined considering their functions in the present invention, and these may vary depending on the intentions or conventions of the user or operator. Therefore, such definitions should be based on the content throughout this specification. The terms used in the detailed description are merely for describing the embodiments of the present invention and should not be limited in any way. Unless explicitly stated otherwise, expressions in the singular form include the meaning of the plural form.

[0033] In this description, expressions such as “include” or “equipped” are intended to refer to certain characteristics, numbers, steps, actions, elements, parts or combinations thereof, and should not be interpreted to exclude the existence or possibility of one or more other characteristics, numbers, steps, actions, elements, parts or combinations thereof other than those described.

[0034] Unless otherwise specifically defined in the specification of the present invention, % units mean weight %.

[0035] In this specification, the terms "substituent," "radical," "group," "moiety," and "fragment" may be used interchangeably.

[0036] The term "CA-CB" in this specification may mean "having a carbon number of A or more and B or less."

[0037] The term "alkyl" in this specification refers to an organic radical derived from an aliphatic hydrocarbon by the removal of one hydrogen, and may include both straight-chain and broken-chain forms. Specific examples of the alkyl include, but are not limited to, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, pentyl, hexyl, ethylhexyl, etc.

[0038] The term "alkylene" in this specification may mean a divalent organic radical derived from a straight-chain or fragmented aliphatic hydrocarbon. Specific examples of the above alkylenes include methylene, ethylene, propylene, n-propylene, isopropylene, butylene, n-butylene, isobutylene, t-butylene, s-butylene, 1-methyl-butylene, 1-ethyl-butylene, pentylene, n-pentylene, isopentylene, neopentylene, t-pentylene, hexylene, n-hexylene, 1-methylpentylene, 2-methylpentylene, 4-methyl-2-pentylene, 3,3-dimethylbutylene, 2-ethylbutylene, heptylene, n-heptylene, 1-methylhexylene, octylene, n-octylene, t-octylene, 1-methylheptylene, 2-ethylhexylene, 2-propylpentylene, n-nonylene, 2,2-dimethylheptylene. Includes, but is not limited to, 1-ethyl-propylene, 1,1-dimethyl-propylene, isohexylene, 2-methylpentylene, 4-methylhexylene, 5-methylhexylene.

[0039] The term "alkenylene" in this specification may mean a hydrocarbon group comprising at least one carbon-carbon double bond. Specific examples of the alkenylene include, but are not limited to, an ethenyl group, a 1-propenyl group, a 2-propenyl group, a 2-methyl-1-propenyl group, a 1-butenyl group, a 2-butenyl group, a cyclopropenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptenyl group, etc.

[0040] The term "alkoxy" in this specification is represented by *-O-alkyl, and the alkyl is as described above. Specific examples of the alkoxy include, but are not limited to, methoxy, ethoxy, propoxy, 2-propoxy, butoxy, tert-butoxy, pentyloxy, hexyloxy, cyclopropoxy, cyclohexyloxy, etc.

[0041] In this specification, "*" refers to a part connected to the same or different atoms or chemical formulas.

[0042] The present invention will be described in detail below through each embodiment or example of the invention. It should be noted that each embodiment or example described in this specification is not limited to a single embodiment or example, but may also be combined with other embodiments or examples. Accordingly, the citation of claims in the patent claims is merely an example of an embodiment, and the technical concept of the present invention should not be interpreted as being limited only to a combination with the cited claims; rather, combinations with various claims are also included within the scope of the technical concept of the present invention.

[0044] An adhesive composition is provided according to one embodiment of the present invention. An adhesive composition according to one embodiment of the present invention comprises a first polyfunctional thiol-based compound prepared from a polymerizable composition comprising (a) a polyether having a polyfunctional hydroxyl group bonded to a polyoxyalkylene linker, (b) a compound having two or more isocyanate groups, and (c) a compound having two or more thiol groups, wherein the polyether of (a) comprises three or more hydroxyl groups bonded to a polyoxyalkylene linker.

[0045] The polyether of (a) can impart flexibility to the adhesive composition. Since the polyether of (a) contains reactive functional groups, which are three or more hydroxyl groups bonded to polyoxyalkylene linkers, it can allow the first polyfunctional thiol-based compound to contain three or more thiol groups, thereby further improving the adhesive properties of the adhesive composition. Specifically, because the polyether of (a) contains polyoxyalkylene linkers, it improves the flexibility of the first polyfunctional thiol-based compound, thereby alleviating the stress received by the adhesive composition due to external impact and improving the stability of the adhesive composition. In addition, since the polyether of (a) has three or more hydroxyl groups, it can significantly improve the crosslinking density of the first polyfunctional thiol-based compound, thereby increasing the adhesive strength of the adhesive composition.

[0046] More specifically, when applying an adhesive composition to a camera module, the adhesive must be strongly maintained between the components because the camera module is highly susceptible to impact from drops or external vibrations due to its characteristics. In particular, as the camera module becomes smaller, the adhesive area between the components and the adhesive composition is reduced, and the adhesive fixing area between the components is prone to peeling off; therefore, improving the adhesive strength per unit area of ​​the adhesive is more important, and the impact resistance must also be excellent. Since the first polyfunctional thiol-based compound is prepared using the polyether of (a) containing three or more hydroxyl groups bonded to a polyoxyalkylene linker as described above, it has the advantage of improving the flexibility and crosslinking density of the first polyfunctional thiol-based compound, and accordingly, can contribute to improving the adhesive strength and impact resistance of the adhesive composition.

[0047] For example, the polyoxyalkylene may be a polyoxy(C2-C6)alkylene. Specifically, it may be a polyoxy(C2-C6)alkylene or a polyoxy(C2-C4)alkylene, and exemplarily, it may be polyoxyethylene (polyethylene oxide, PEO) or polyoxypropylene (polypropylene oxide, PPO).

[0048] For example, the polyether of (a) can be represented by the following chemical formula 1.

[0049] [Chemical Formula 1]

[0050]

[0051] In the above chemical formula 1, R is independently hydrogen or (C1-C10)alkyl, and x, y, and z are independently integers from 10 to 100.

[0052] For example, in the above chemical formula 1, the number of carbon atoms of the alkyl group may be 1 to 10, specifically 1 to 7, more specifically 1 to 4, and even more specifically 1 to 2. In addition, x, y, or z may be integers from 10 to 100, specifically integers from 10 to 80, and more specifically 15 to 70, 20 to 50, or 22 to 45.

[0053] As a specific example, in the above chemical formula 1, R can each independently be hydrogen or (C1-C4)alkyl, and x, y, and z can each independently be integers from 10 to 100.

[0054] For example, the polyether of (a) may include a linear and / or branched polyether having a plurality of ether bonds and three or more hydroxyl groups. For example, the polyether of (a) may include linear and / or branched polyether homopolymers and copolymers, and specifically may include a polyoxyalkylene polyol having a repeating unit having C2-C4 carbon atoms, more specifically a polyoxyethylene polyol.

[0055] For example, the polyether of (a) may be derived from a trihydric alcohol and a cyclic oxide monomer. For example, the cyclic oxide monomer may include one or more selected from the group consisting of ethylene oxide, propylene oxide, 1,2-butylene oxide, and 1,4-butylene oxide. The polyether of (a) may be synthesized using various synthesis methods known in the industry, but is not limited thereto, and the polyether of (a) may be a commercially available polyether.

[0056] For example, the number average molecular weight (Mn) of the polyether of (a) may be 500 to 7000 g / mol, 1000 to 6500 g / mol, 1500 to 6000 g / mol, or 2000 to 6000 g / mol.

[0057] For example, the compound of (b) may include an aliphatic diisocyanate. As a specific example, the aliphatic diisocyanate may include a (C3-C10)aliphatic diisocyanate. For example, the number of carbon atoms in the aliphatic diisocyanate may be 3 to 10, 3 to 9, or 4 to 8. As a non-limiting example, the (C3-C10)aliphatic diisocyanate may include one or more selected from the group consisting of hexamethylene diisocyanate, isophorone diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, propylene diisocyanate, butylene diisocyanate, and dodecamethylene diisocyanate. As the compound of (b) contains an aliphatic diisocyanate, the glass transition temperature of the adhesive composition is reduced, so the camera module can be stably supported even by impact from dropping or external vibration.

[0058] For example, the compound of (c) may include an aliphatic dithiol. As a specific example, the aliphatic dithiol may include a (C1-C15)aliphatic dithiol. For example, the number of carbon atoms in the aliphatic dithiol may be 1 to 15, 2 to 12, 3 to 10, or 3 to 8. As a non-limiting example, the (C1-C15)aliphatic dithiol may include one or more selected from the group consisting of hexanedithiol, methanedithiol, ethanedithiol, butanedithiol, pentanedithiol, octanedithiol, nonanedithiol, and decanedithiol. As the compound of (c) includes an aliphatic dithiol, the flexibility of the first polyfunctional thiol-based compound may be improved. Accordingly, the adhesive composition containing the first polyfunctional thiol-based compound may have stress relieved by external impact and may be suitable for use in applications such as camera modules.

[0059] For example, the polymerizable composition may contain the polyether of (a) and the compound of (b) in a molar ratio of 1:1 to 5, 1:1 to 4.5, 1:1.5 to 4.5, or 1:2 to 4. Additionally / alternatively, the polymerizable composition may contain the polyether of (a) and the compound of (c) in a molar ratio of 1:1 to 5, 1:1 to 4.5, 1:1.5 to 4.5, or 1:2 to 4.

[0060] For example, the first polyfunctional thiol compound can be represented by the following chemical formula 2.

[0061] [Chemical Formula 2]

[0062]

[0063] In the above formula 2, R is each independently hydrogen or (C1-C10)alkyl, x, y, and z are each independently integers from 10 to 100, L1 is each independently (C1-C8)alkylene, (C1-C8)alkenylene, or a combination thereof, L2 is each independently (C1-C15)alkylene, (C1-C15)alkenylene, or a combination thereof, and the hydrogens of L1 and L2 can each be independently substituted with one or more substituents selected from halogen, nitro, cyano, (C1-C7)alkyl, and (C1-C7)alkoxy.

[0064] For example, in the above formula 2, the number of carbon atoms of the L1 alkylene or alkenylene may be 1 to 8, specifically 1 to 7 or 2 to 6. In addition, in the above formula 2, the number of carbon atoms of the L2 alkylene or alkenylene may be 1 to 15, specifically 2 to 12, and more specifically 3 to 10 or 3 to 8.

[0065] As a specific example, in the above chemical formula 2, R may each independently be hydrogen or (C1-C4)alkyl, x, y, and z may each independently be integers from 10 to 100, L1 may be (C1-C6)alkylene, and L2 may be (C1-C6)alkylene.

[0066] For example, the first polyfunctional thiol-based compound may be prepared by a method comprising: a step of reacting the polyether of (a) with the compound of (b) to prepare a compound having urethane bonds; and a step of reacting the compound having urethane bonds with the compound of (c) to prepare the first polyfunctional thiol-based compound. For example, the step of preparing the compound having urethane bonds or the step of preparing the first polyfunctional thiol-based compound may be performed at 10 to 150°C, specifically 20 to 100°C, more specifically 25 to 60°C.

[0067] For example, the number average molecular weight (Mn) of the first polyfunctional thiol compound may be 1,000 to 8,000 g / mol, 1,500 to 7,500 g / mol, 1,500 to 7,000 g / mol, or 2,000 to 7,000 g / mol.

[0068] For example, the first polyfunctional thiol-based compound may be included in an amount of 5 to 20 weight%, specifically 7 to 17 weight%, and more specifically 7 to 15 weight% based on the total weight of the adhesive composition. When the content of the first polyfunctional thiol-based compound satisfies the above range, the adhesive composition can further improve impact resistance while securing excellent adhesion.

[0069] As the first polyfunctional thiol-based compound described above possesses excellent adhesive performance and impact resistance, it can be preferably used as an adhesive. As described below, when the first polyfunctional thiol-based compound is mixed with the second polyfunctional thiol-based compound, the mechanical properties of the adhesive composition are improved, allowing the adhesive composition deformed by external impact to recover easily, thereby minimizing the degradation of adhesive performance. Accordingly, a cured product prepared from an adhesive composition according to one embodiment of the present invention can be usefully applied as a material for forming various optical members and optical devices, and in particular, it can be usefully applied as an adhesive layer between constituent members such as camera modules where high adhesive strength and impact resistance per unit area are required.

[0070] For example, the adhesive composition further comprises a second polyfunctional thiol compound, and the second polyfunctional thiol compound may include one or more selected from the group consisting of tris[2-(3-mercaptopropionyloxy)ethyl]isocyanurate, 1,4-bis(3-mercaptobutyryloxy)butane, 1,3,5-tris(3-mercaptobutyloxyethyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetra(3-mercaptobutylate), pentaerythritol tetra(3-mercaptopropionate), dipentaerythritol hexa(3-mercaptopropionate), and tetraethyleneglycol bis(3-mercaptopropionate).

[0071] For example, the weight ratio of the first polyfunctional thiol-based compound and the second polyfunctional thiol-based compound may be 1:0.5 to 3.5, specifically 0.5 to 2.5, and more specifically 1:0.5 to 2.0. When the weight ratio of the first polyfunctional thiol-based compound and the second polyfunctional thiol-based compound satisfies the above range, the mechanical properties of the adhesive composition are appropriately controlled, thereby preventing the occurrence of cracks caused by external impact.

[0072] For example, the adhesive composition may further include a polyfunctional acrylate-based compound and a photoinitiator.

[0073] For example, a polyfunctional acrylate compound may include one or more selected from the group consisting of dipentaerythritol hexa(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, trimethylpropane tri(meth)acrylate, glycerol tri(meth)acrylate, tris(2-hydroxyethyl)isocyanurate, tri(meth)acrylate, di-trimethylpropane tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, and pentaerythritol tetra(meth)acrylate.

[0074] For example, a polyfunctional acrylate-based compound may be included in an amount of 1 to 20 weight%, specifically 5 to 17 weight%, more specifically 5 to 15 weight% based on the total weight of the adhesive composition.

[0075] For example, photoinitiators may be used without limitation as long as they are ordinary. As a non-limiting example, photoinitiators include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, hydroxydimethylacetophenone, dimethylaminoacetophenone, dimethoxy-2-phenylacetophenone, 3-methylacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 4-chronolocetophenone, 4,4-dimethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 4-hydroxycyclophenylketone, 1-hydroxycyclohexylphenylketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propan-1-one, 4-(2-hydroxyethoxy)phenyl-2-(hydroxy-2-propyl)ketone, benzophenone, p-phenylbenzophenone, 4,4-diaminobenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, anthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-t-butylanthraquinone, 2-aminoanthraquinone, β-chloroanthraquinone, 2-methylthioxantone, 2-ethylthioxantone, 2-chlorothioxantone, 2,4-dimethylthioxantone, 2,4-diethylthioxantone, benzyldimethylketal, diphenylketonebenzyldimethylketal, acetophenonedimethylketal, It may include p-dimethylaminobenzoic acid ester, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, fluorene, triphenylamine, carbazole, benzyldiphenylsulfide, or tetramethylthiuram monosulfide, etc., and may include one or more mixtures selected from these. In addition, for example, the photoinitiator may be a commercially available product such as trade name Darocur 1173, Irgacure 184, or Igacure 907 (Ciba), etc., and may be used as one or more mixtures selected from these.

[0076] For example, the photoinitiator may be included in an amount of 0.01 to 5 weight%, 0.05 to 3 weight%, 0.1 to 3 weight%, or 0.1 to 2 weight% based on the total weight of the adhesive composition.

[0077] For example, the adhesive composition may further include a thermosetting agent and a filler.

[0078] For example, the thermosetting agent may include, but is not limited to, a polyfunctional epoxy-containing compound, and may include a compound that can prevent thermosetting from starting at a desired temperature (room temperature, 25°C) or lower, such as, an imidazole-based compound, a dihydrazide-based compound, or an amine-based compound.

[0079] For example, a polyfunctional epoxy-containing compound may contain epoxy groups of two or more functions. As a non-limiting example, the polyfunctional epoxy-containing compound may include one or more selected from the group consisting of novolak-type epoxy resin, bisphenol A-type epoxy resin, bisphenol F-type epoxy resin, bisphenol E-type epoxy resin, biphenyl-type epoxy resin, triphenylmethane-type epoxy resin, phenol-aralkyl-type epoxy resin, halogenated epoxy resin, alicyclic epoxy resin, rubber-modified epoxy resin, aliphatic polyglycidyl-type epoxy resin, glycidyl amine-type epoxy resin, polyglycol epoxy resin, and cardanol epoxy resin.

[0080] For example, a polyfunctional epoxy-containing compound may be included in an amount of 5 to 40 weight%, specifically 10 to 35 weight%, more specifically 15 to 35 weight%, based on the total weight of the adhesive composition.

[0081] For example, the filler may be used without limitation as long as it is a conventional one. As a non-limiting example, the filler may include silica, diatomaceous earth, alumina, zinc oxide, iron oxide, magnesium oxide, tin oxide, titanium oxide, magnesium hydroxide, aluminum hydroxide, magnesium carbonate, barium sulfate, gypsum, calcium silicate, talc, glass beads, sericite, talc clay, bentonite, aluminum nitride, silicon nitride, potassium titanate, zeolite, calcia, magnesia, and ferrite, and may include one or more mixtures selected from these.

[0082] For example, the filler may be included in an amount of 5 to 50 weight%, specifically 10 to 40 weight%, more specifically 20 to 40 weight% based on the total weight of the adhesive composition.

[0083] For example, the adhesive composition may be one-component. For example, the adhesive composition may be usefully applied as a structural adhesive. Here, "structural adhesive" may refer to a material used to adhesively bond at least two structural parts constituting a structure together.

[0084] For example, the adhesive composition may have thermosetting properties. For example, the thermosetting may be performed under temperature conditions of 70 to 120°C, specifically 80 to 100°C, more specifically 80 to 90°C.

[0085] For example, the adhesive composition may have photocurability. For example, the photocuring may be performed by irradiating with light such as infrared, visible light, ultraviolet, or electron beam with a wavelength of 800 nm or more. Specifically, the light may be ultraviolet, and the peak wavelength of the ultraviolet may be in the range of 300 to 500 nm.

[0086] For example, the light may be applied in the range of 100 to 5000 mW / cm², 300 to 4000 mW / cm², or 500 to 3000 mW / cm² for 1 to 30 seconds, 1 to 20 seconds, or 3 to 10 seconds. Additionally, for example, the photocuring may be performed under irradiation conditions of 2.0 to 10.0 J / cm², specifically 2.0 to 4.0 J / cm², and more specifically 2.0 to 2.5 J / cm².

[0087] For example, the light irradiation means may use a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, an excimer laser, a chemical lamp, a black light lamp, a microwave-excited mercury lamp, a metal halide lamp, a sodium lamp, a fluorescent lamp, an LED-type spot-type UV irradiator, a xenon lamp, or a deep UV lamp.

[0088] As described above, the adhesive composition can simultaneously possess thermosetting and photocuring properties, and by combining them, further improved adhesive strength can be achieved. More specifically, a primary cured product can be stably formed by photocuring in the first step, and a cured product having further improved adhesive strength can be formed by thermosetting in the second step.

[0090] According to another embodiment of the present invention, a cured product of an adhesive composition is provided. The cured product of an adhesive composition according to one embodiment of the present invention is formed by performing dual curing, namely photocuring and thermal curing, on the adhesive composition described above.

[0091] Specifically, the adhesive composition described above is prepared using the polyether of (a) which comprises three or more hydroxyl groups bonded to a polyoxyalkylene linker, and because it includes a first polyfunctional thiol-based compound having improved flexibility and crosslinking density, the cured product thereof can also have improved adhesive strength and impact resistance.

[0092] For example, a cured product of an adhesive composition may have excellent adhesive strength. For example, a cured product of an adhesive composition may have an adhesive strength of 55 kgf or more, 60 kgf or more, 70 kgf or more, 70 to 200 kgf, 70 to 150 kgf, 75 to 150 kgf, or 80 to 140 kgf.

[0093] For example, the cured product of the adhesive composition can exhibit not only excellent adhesive strength but also superior moisture resistance even under high temperature and high humidity conditions. Accordingly, the cured product of the adhesive composition can be usefully utilized for applications such as adhesives, sealants, or coatings. Furthermore, the cured product of the adhesive composition can be usefully applied as an adhesive layer between components, such as camera modules, that require high adhesive strength and water resistance per unit area. It can also be utilized as a structural adhesive in the assembly of transportation vehicles, such as automobiles, aircraft, and ships, as well as in structures like civil engineering buildings. This enables diverse applications across various industries by realizing excellent adhesive performance between identical or different materials, such as metal and metal, metal and glass, or metal and carbon fiber.

[0094] For example, the modulus of the cured product of the adhesive composition may be 50 to 3000 Pa, specifically 70 to 2000 Pa, 100 to 1500 Pa, or 200 to 1400 Pa, and more specifically 300 to 1000 Pa. When the modulus of the cured product of the adhesive composition satisfies the above range, impact resistance is significantly improved, and problems such as cracking caused by external impact and reduced adhesion due to deformation can be improved.

[0096] A camera module is provided according to another embodiment of the present invention. A camera module according to one embodiment of the present invention comprises: a first substrate; a second substrate; and an adhesive layer provided between the first substrate and the second substrate, comprising a cured product of the adhesive composition described above.

[0097] Specifically, since the cured product of the adhesive composition described above possesses excellent adhesive strength, moisture resistance, and impact resistance, it can be usefully applied as an adhesive layer between components, such as camera modules, that require high adhesive strength and water resistance per unit area. For example, the camera module may include a camera module mounted on a portable device such as a smartphone or a camera module for a vehicle.

[0098] For example, the first substrate and the second substrate may be made of aluminum, brass, or polycarbonate. For example, the first substrate and the second substrate may be selected from a lens, a lens holder, or a housing, and a high-quality structure may be formed by bonding a part or the whole with high adhesive strength by the adhesive layer.

[0100] The present invention will be described in detail below through examples. However, it should be noted that the examples described below are intended merely to illustrate and embody the present invention and are not intended to limit the scope of the present invention. This is because the scope of the present invention is determined by the matters described in the patent claims and matters reasonably inferred therefrom.

[0101] [Preparation of the first polyfunctional thiol compound]

[0102] (1) Preparation of the first polyfunctional thiol compound A

[0103] In the presence of 300 ppm of DBDTL as a catalyst, a polyether (product name: Sigma-Aldrich PEG 3000, number average molecular weight: 3000 g / mol) and hexamethylene diisocyanate were mixed in a molar ratio of 1:3 (mixed amount of polyether: 1 kg, mixed amount of hexamethylene diisocyanate: 0.25 kg), and then reacted at a temperature of 60°C for 2 hours to prepare a compound having urethane bonds. Subsequently, 1,6-hexanedithiol and the compound having urethane bonds were mixed (mixed amount of 1,6-hexanedithiol: 0.23 kg) such that the molar ratio of the polyether added in the aforementioned step to 1,6-hexanedithiol was 1:3, and then reacted at a temperature of 60°C for 2 hours to prepare the first polyfunctional thiol-based compound A.

[0104] (2) Preparation of the first polyfunctional thiol compound B

[0105] A first polyfunctional thiol-based compound B was prepared by carrying out the same method as above, except that a polyether having a number average molecular weight of 4000 g / mol (product name: PEG 4000 of Sigma-Aldrich) was used in the method for preparing the first polyfunctional thiol-based compound A.

[0106] (3) Preparation of the first polyfunctional thiol compound C

[0107] A first polyfunctional thiol-based compound C was prepared by carrying out the same method as above, except that a polyether having a number average molecular weight of 5000 g / mol (product name: PEG 5000 of Sigma-Aldrich) was used in the method for preparing the first polyfunctional thiol-based compound A.

[0109] [Preparation of adhesive composition]

[0110] An adhesive composition was prepared with the composition and content listed in Table 1 below.

[0111] division Photocuring agent thermosetting agent Filler total Polyfunctional acrylate compounds 1st polyfunctional thiol compound A 1st polyfunctional thiol compound B 1st polyfunctional thiol compound C Secondary polyfunctional thiol compound A Secondary polyfunctional thiol compound B Secondary polyfunctional thiol compound C Photoinitiator Polyfunctional epoxy-containing compounds hardening catalyst fumed silica Fused silica Example 1 10 20 - - - - - 1 25 15 4 25 100 Example 2 10 - 20 - - - - 1 25 15 4 25 100 Example 3 10 - - 20 - - - 1 25 15 4 25 100 Example 4 10 5 - - 15 - - 1 25 15 4 25 100 Example 5 10 - 5 - 15 - - 1 25 15 4 25 100 Example 6 10 - - 5 15 - - 1 25 15 4 25 100 Example 7 10 10 - - 10 - - 1 25 15 4 25 100 Example 8 10 - 10 - 10 - - 1 25 15 4 25 100 Example 9 10 - - 10 10 - - 1 25 15 4 25 100 Comparative Example 1 10 - - - 20 - - 1 25 15 4 25 100 Comparative Example 2 10 - - - 10 10 - 1 25 15 4 25 100 Comparative Example 3 10 - - - 10 - 10 1 25 15 4 25 100 - Polyfunctional acrylate compound: Tris[2-(acryloyloxy)ethyl] isocyanurate (Product name: SR368 NS) - Secondary polyfunctional thiol compound A: Pentaerythritol tetrakis(3-mercaptopropionate) (Product name: PEMP) - Secondary polyfunctional thiol compound B: - Secondary polyfunctional thiol compound C: (In the above chemical formulas, R and x represent the same meaning as R and x of Chemical Formula 1, respectively) - Photoinitiator: 1-Hydroxycyclohexyl phenyl ketone (Product name: Irgacure 184) - Polyfunctional epoxy-containing compound: Bisphenol A diglycidyl ether (Product name: YD-128K) - Curing catalyst: Epoxy-imidazole Adduct (Product name: P-0505)

[0113] [Evaluation Method]

[0114] [Adhesion Strength Evaluation]

[0115] A cell was manufactured by dispensing an adhesive composition onto the lower aluminum interface in the form of an inner diameter of 12.4 mm and an outer diameter of 16.5 mm, and then bonding it to the upper interface. At this time, the gap between the lower and upper interfaces was set to 300 μm, and the applied epoxy adhesive was maintained at a level of 50 mg. For the manufactured cell, a first curing was performed using four light sources (1,000 mW / cm², 7 s) with an LED wavelength of 365 nm, while maintaining a distance of 25 mm between the adhesive and the light source in the horizontal direction of the cell. Subsequently, a second curing was performed by heating in a thermal circulating oven at 80°C for 1 hour.

[0116] The adhesive strength of the above-mentioned cured cell was measured using an AMETEK LD50, with the tensile speed set to 30 mm / sec.

[0117] [Reliability Assessment]

[0118] (1) Reliability evaluation for constant temperature / humidity

[0119] The adhesive strength was measured after exposing the above-mentioned cured cell to an environment maintained at 85°C and 85%RH for 500 hours using a constant temperature / humidity chamber, and the reliability for constant temperature / humidity was evaluated according to the following criteria.

[0120] - ×: Adhesion strength decreased by 20% or more compared to the cell before reliability evaluation

[0121] - ○: Less than 20% decrease in adhesion compared to the cell before reliability evaluation

[0122] (2) Reliability evaluation against thermal shock

[0123] For the above-mentioned cured cells, 30 minutes at -40℃ and 30 minutes at 85℃ were used as one cycle, and the adhesion strength after 500 cycles was measured, and the reliability against thermal shock was evaluated according to the following criteria.

[0124] - ×: Adhesion strength decreased by 20% or more compared to the cell before reliability evaluation

[0125] - ○: Less than 20% decrease in adhesion compared to the cell before reliability evaluation

[0126] [Storage Stability Assessment]

[0127] The adhesive composition was stored in a plastic sealed container at 25°C for 72 hours, and the viscosity before and after storage was measured (Equipment: Brookfield cone plate, Spindle: 51z) to evaluate storage stability according to the following criteria.

[0128] - ×: Increase of 20% or more compared to viscosity before storage

[0129] - ○: Less than 20% increase compared to viscosity before storage

[0130] [Impact Resistance Evaluation]

[0131] When the above-mentioned cured cell was dropped from a height of 1m, the appearance of the cell was observed and the impact resistance was evaluated according to the following criteria.

[0132] - ×: Cracks and delamination occur in the cells after drop

[0133] - ○: No cracking or delamination occurred in the cell after drop

[0134] [Modulus Measurement]

[0135] For the adhesive composition, a first curing was performed using four light sources (1,000 mW / cm², 7 s) with an LED wavelength of 365 nm while maintaining a distance of 25 mm between the adhesive and the light source in the horizontal direction of the composition. Subsequently, a second curing was performed by heating in a thermal circulating oven at 80°C for 1 hour to produce a cured specimen with a width of 16 mm, a depth of 5 mm, and a height of 0.4 mm.

[0136] The modulus of the above-mentioned cured specimen was measured at room temperature using TA's DMA Q800 instrument.

[0138] [Evaluation Example 1: Use of primary polyfunctional thiol-based compound alone]

[0139] For the adhesive compositions of Examples 1 to 3 and Comparative Examples 1 to 3 above, adhesive strength, reliability, storage stability, impact resistance, and modulus were evaluated, and the results are shown in Table 2.

[0140] division Example 1 Example 2 Example 3 Adhesion (kgf) 75 70 73 reliability Constant temperature / humidity ○ ○ ○ thermal shock ○ ○ ○ Storage stability ○ ○ ○ Impact resistance ○ ○ ○ Modulus(Pa) 200 150 75

[0141] Referring to Table 2, Examples 1 to 3 showed an adhesive strength of 70 to 75 kgf and a modulus of 75 to 200 Pa. In addition, Examples 1 to 3 ensured reliability against constant temperature / humidity and thermal shock, storage stability, and impact resistance.

[0142] Meanwhile, in the case of Comparative Example 1, which did not contain the first polyfunctional thiol-based compound, the modulus was found to be very high at 3200 Pa. Accordingly, it was confirmed that Comparative Example 1 had reduced reliability against impact and thermal shock, such as by absorbing external shocks and causing cracks.

[0143] In the case of Comparative Example 2, which contains a second polyfunctional thiol compound B instead of a first polyfunctional thiol compound, it was found that reliability and impact resistance against constant temperature / humidity and thermal shock could not be secured. That is, since Examples 1 to 3 contain a first polyfunctional thiol compound with improved flexibility through polyoxyalkylene linkers, it was found that stress caused by external shock is alleviated and stability is improved.

[0144] Comparative Example 3, which contains a second polyfunctional thiol compound C instead of a first polyfunctional thiol compound, was also found to fail to secure reliability and impact resistance against constant temperature / humidity and thermal shock. In other words, since Examples 1 to 3 contain a first polyfunctional thiol compound with improved flexibility and crosslinking density through three or more functional groups, it was found that impact resistance is also improved.

[0146] [Evaluation Example 2: Used in combination with a secondary polyfunctional thiol compound]

[0147] For the adhesive compositions of Examples 4 to 9 above, adhesive strength, reliability, storage stability, impact resistance, and modulus were evaluated, and the results are shown in Table 3.

[0148] division Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Adhesion (kgf) 115 121 118 102 109 111 reliability Constant temperature / humidity ○ ○ ○ ○ ○ ○ thermal shock ○ ○ ○ ○ ○ ○ Storage stability ○ ○ ○ ○ ○ ○ Impact resistance × × × ○ ○ ○ Modulus(Pa) 1750 1530 1400 600 550 420

[0149] Referring to Table 3, Examples 4 to 9 showed an adhesive strength of 102 to 121 kgf and a modulus of 420 to 1750 Pa.

[0150] In particular, Examples 4 to 9 showed higher adhesive strength and modulus than Examples 1 to 3. That is, it was found that when the first polyfunctional thiol-based compound and the second polyfunctional thiol-based compound are used in combination, the modulus is appropriately controlled, and the adhesive performance of the adhesive composition is also improved.

[0151] In addition, it was confirmed that Examples 7 to 9 secured excellent impact resistance by controlling the modulus to be lower than that of Examples 4 to 6. That is, it was found that stability against external impact is improved when the weight ratio of the first polyfunctional thiol-based compound and the second polyfunctional thiol-based compound is controlled.

[0152] The above embodiments are merely examples, and the present invention is not limited thereto. Any configuration having substantially the same structure as the technical concept described in the claims of the present invention and achieving the same functional effect is included within the technical scope of the present invention.

Claims

Claim 1 An adhesive composition comprising a first polyfunctional thiol-based compound prepared from a polymerizable composition comprising (a) a polyether having a polyfunctional hydroxyl group bonded by a polyoxyalkylene linker, (b) a compound having two or more isocyanate groups, and (c) a compound having two or more thiol groups, wherein the polyether of (a) comprises a reactive functional group which is three or more hydroxyl groups bonded by a polyoxyalkylene linker, and the first polyfunctional thiol-based compound comprises three or more thiol groups at the terminal end. Claim 2 The adhesive composition according to claim 1, wherein the polyether of (a) is represented by the following chemical formula 1. [Chemical Formula 1] (In the above Chemical Formula 1, R is each independently hydrogen or (C1-C10)alkyl, and x, y, and z are each independently integers from 10 to 100) Claim 3 An adhesive composition according to claim 1, wherein the compound of (b) comprises a (C3-C10) aliphatic diisocyanate. Claim 4 An adhesive composition according to claim 1, wherein the compound of (c) comprises a (C1-C15) aliphatic dithiol. Claim 5 The adhesive composition according to claim 1, wherein the first polyfunctional thiol-based compound is represented by the following chemical formula 2. [Chemical Formula 2] (In the above formula 2, R is each independently hydrogen or (C1-C10)alkyl, x, y, and z are each independently integers from 10 to 100, L1 is each independently (C1-C8)alkylene, (C1-C8)alkenylene, or a combination thereof, L2 is each independently (C1-C15)alkylene, (C1-C15)alkenylene, or a combination thereof, and the hydrogens of L1 and L2 may each independently be substituted with one or more substituents selected from halogen, nitro, cyano, (C1-C7)alkyl, and (C1-C7)alkoxy.) Claim 6 An adhesive composition according to claim 1, wherein the first polyfunctional thiol-based compound is included in an amount of 7 to 17 weight% based on the total weight of the adhesive composition. Claim 7 The adhesive composition of claim 1 further comprises a second polyfunctional thiol compound, wherein the second polyfunctional thiol compound comprises one or more selected from the group consisting of tris[2-(3-mercaptopropionyloxy)ethyl]isocyanurate, 1,4-bis(3-mercaptobutyryloxy)butane, 1,3,5-tris(3-mercaptobutyloxyethyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetra(3-mercaptobutylate), pentaerythritol tetra(3-mercaptopropionate), dipentaerythritol hexa(3-mercaptopropionate), and tetraethyleneglycol bis(3-mercaptopropionate). Claim 8 An adhesive composition according to claim 7, wherein the weight ratio of the first polyfunctional thiol-based compound and the second polyfunctional thiol-based compound is 1:0.5 to 2.

5. Claim 9 The adhesive composition according to claim 1, wherein the adhesive composition further comprises a polyfunctional acrylate-based compound and a photoinitiator. Claim 10 The adhesive composition according to claim 1, wherein the adhesive composition further comprises a thermosetting agent comprising a polyfunctional epoxy-containing compound; and a filler. Claim 11 In claim 1, the adhesive composition is a one-component adhesive composition. Claim 12 A camera module comprising: a first substrate; a second substrate; and an adhesive layer provided between the first substrate and the second substrate, the adhesive layer comprising a cured product of an adhesive composition according to any one of claims 1 to 11.

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