Light-curing sealing material

Abstract

A photocurable sealing material containing at least a polythiol compound as a first component, wherein when two sheets of 1 mm thick, 25 mm wide, and 200 mm long are prepared using the photocurable sealing material, and then photocured by irradiating them with ultraviolet light, the two sheets are laminated together, and a load of 10 kg is applied for 10 seconds, the laminated interface between the two sheets disappears, and the self-adhesion strength in a T-peel test is 5 N / 25 mm or more when pulled at a peel speed of 300 mm / min.

Description

[Technical Field]

[0001] The present invention relates to a photocurable sealing material, and more particularly to a photocurable sealing material having excellent sealing properties such as waterproofness. [Background technology]

[0002] In recent years, there has been increasing customer demand for products with high sealing properties (waterproofing and airtightness) in the housings of electronic components such as digital cameras and video cameras, home appliances such as refrigerators, air conditioners and washing machines, and precision instruments such as cameras and watches. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2014 / 069027 Summary of the Invention [Problem to be solved by the invention]

[0004] Known conventional sealing materials include, for example, hot melt adhesives, one-component urethane-based reactive hot melt adhesives, thermoplastic hot melt sealing materials, moisture-curing hot melt sealing materials, thermosetting sealing materials, and two-component urethane-based foam sealing materials. Insufficient heat resistance and waterproofing, etc. The operation is complicated, such as preventing moisture from entering the device. Heating equipment is required, There are concerns about thermal damage to the housing. The operability of manufacturing using a mold is complicated; There are problems such as the above, and there is no material that can impart fully satisfactory sealing properties to the housings of electronic components, home appliances, precision instruments, etc., and there is a demand for such a material.

[0005] Photocurable sealing materials can be produced on a housing without using a mold, making them easier to use and more suitable for mass production than conventional sealing materials.

[0006] Photocurable sealing materials mainly include those that use the radical polymerization of acryloyl groups and those that use the ene-thiol reaction. Photocurable sealing materials that use the radical polymerization of acryloyl groups are produced by curing a composition consisting of, for example, a urethane acrylate oligomer, an acrylate monomer, and a photopolymerization initiator (and a photosensitizer) with light or the like.

[0007] However, these photocurable sealing materials do not provide complete waterproofing for parts that need to hold inserted objects (cables, wires, etc.) in electronic products, home appliances, precision instruments, automobiles, etc., and water often seeps in through small gaps, so they do not exhibit sufficient sealing properties.

[0008] In view of the above circumstances, an object of the present invention is to provide a photocurable sealing material that is excellent in airtightness and waterproofness. [Means for solving the problem]

[0009] As a result of intensive research to solve the above problems, the present inventors have found that a photocurable sealant material containing at least a polythiol compound as a first component, when used to prepare a sheet of a predetermined size, exhibits predetermined self-adhesion and self-adhesion strength, and has particularly excellent airtightness and waterproofness, thereby completing the present invention. That is, the present invention is as follows. [1] A photocurable sealing material containing at least a polythiol compound as a first component, The photocurable sealing material is used to prepare two sheets each 1 mm thick, 25 mm wide, and 200 mm long, which are then photocured by irradiating them with ultraviolet light. When the two sheets are then laminated together and a load of 10 kg is applied for 10 seconds, the laminated interface between the two sheets disappears, and the self-adhesion strength in a T-peel test is 5 N / 25 mm or more when pulled at a peel speed of 300 mm / min. [2] The photocurable sealing material according to [1], wherein the self-adhesion strength is 1000 N / 25 mm or less when pulled at a peel rate of 300 mm / min. [3] The photocurable sealing material according to [1] or [2], wherein the Shore 00 hardness of the sheet after photocuring is 5 to 100 under an environment of 23°C and a relative humidity of 50 to 60% RH. [4] In addition to the first component, the second component and the third component are included; and Further comprising a fourth component and / or a fifth component, the second component is an oligomer having a (meth)acryloyl group and a weight average molecular weight of 1,000 to 30,000, the third component is a monomer having a (meth)acryloyl group, the fourth component is a photoradical polymerization initiator, The fifth component is a viscosity modifier, The third component is contained in an amount of 5 to 100 parts by mass relative to 100 parts by mass of the second component, The photocurable sealing material according to any one of [1] to [3], wherein the ratio of the total number of (meth)acryloyl groups contained in both the second component and the third component to the total number of mercapto groups in the first component is 100:5n to 100:25n (n is the number of mercapto groups in one molecule of the polythiol compound). [5] The photocurable sealing material according to [4], wherein the second component comprises at least one selected from the group consisting of urethane-based (meth)acrylate oligomers, polyester-based (meth)acrylate oligomers, polyether-based (meth)acrylate oligomers, (meth)acrylic (meth)acrylate oligomers, epoxy-based (meth)acrylate oligomers, conjugated diene polymer-based (meth)acrylate oligomers, and silicone (meth)acrylate oligomers, as well as hydrogenated products thereof. [6] The photocurable sealant material according to [4] or [5], further comprising a carbodiimide compound as a sixth component in an amount of 0.1 to 15 parts by mass per 100 parts by mass of the second component. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a photocurable sealing material that is excellent in airtightness and waterproofness. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 2 is a schematic top cross-sectional view illustrating the configuration of a specimen for waterproofness evaluation. [Figure 2] FIG. 2 is a schematic cross-sectional side view illustrating the configuration of a specimen for waterproofness evaluation. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention (hereinafter also referred to as "present embodiments") will be described, but the present invention is not limited to these. Herein, in this specification, an expression in the form of "A to B" means the upper and lower limits of a range (i.e., A or more and B or less), and when no unit is specified for A and a unit is specified only for B, the unit of A and the unit of B are the same.

[0013] (Photo-curable sealing material) The photocurable sealing material according to this embodiment is a photocurable sealing material containing at least a polythiol compound as a first component, and when two sheets of 1 mm thick, 25 mm wide, and 200 mm long are prepared using the photocurable sealing material, and then photocured by irradiating with ultraviolet light, the two sheets are laminated together, and a load of 10 kg is applied for 10 seconds. When the two sheets are laminated together, the lamination interface between the two sheets disappears, and the self-adhesion strength in a T-peel test is 5 N / 25 mm or more when pulled at a peel speed of 300 mm / min. for By having such a configuration, the material exhibits a predetermined self-adhesive property and exhibits the effects of excellent airtightness and waterproofness. Hereinafter, airtightness and waterproofness may be collectively referred to as "sealing properties."

[0014] Here, "laminar interface" refers to the boundary surface where the two sheets are stacked facing each other. "Self-adhesion" refers to the property where, when the two sheets are stacked, the two sheets bond together and become one, making the lamination interface indistinguishable (the property where the lamination interface disappears). In other words, the photocurable sealing material can be understood to exhibit self-adhesion when two sheets are prepared under the above-mentioned conditions, irradiated with ultraviolet light to photo-cure, and then the two sheets are stacked and a load of 10 kg is applied for 10 seconds.

[0015] The ultraviolet light emitted from a metal halide light source is used to irradiate the two sheets for photo-curing. An example of such a metal halide light source is an electrodeless metal halide lamp type UV irradiation device (product name: FOTOCURE TFL-150) manufactured by Tokyo Photon Co., Ltd.

[0016] When confirming the disappearance of the lamination interface between the two sheets, the cumulative UV-A light intensity of the ultraviolet light for photo-curing the two sheets was 6000 mJ / cm 2 is.

[0017] The 10 kg load applied when the two sheets are stacked is applied uniformly to the main surfaces of the sheets. An example of a device that can apply such a uniform load is the tensile tester manufactured by Orientec Co., Ltd. (now A&D Co., Ltd.). Experience Examples include machines.

[0018] When the two sheets are stacked and a load of 10 kg is applied for 10 seconds, "10 seconds" means that the state in which the 10 kg load is applied to the two stacked sheets is maintained for 10 seconds.

[0019] The "effect of the lamination interface between the two sheets disappearing" is confirmed at 50x magnification using a digital microscope manufactured by ANMO Electronics.

[0020] The "self-adhesion strength" according to the present embodiment refers to the breaking strength of the two laminated sheets. The self-adhesion strength is 5 N / 25 mm or more, preferably 15 N / 25 mm or more, when pulled at a peel rate of 300 mm / min. The self-adhesion strength is more preferably 40 N / 25 mm or more, and even more preferably 80 N / 25 mm or more, when pulled at a peel rate of 300 mm / min. The upper limit of the self-adhesion strength is, for example, preferably 1000 N / 25 mm or less, more preferably 800 N / 25 mm or less, and even more preferably 300 N It is more preferable that the thickness is 25 mm or less.

[0021] The T-peel test for measuring the self-adhesion strength is carried out using a tensile tester (manufactured by Orientec Co., Ltd. (now A&D Co., Ltd.), product name: RTC-1310A).

[0022] <Component 1: Polythiol compound> The polythiol compound as the first component refers to a compound having two or more mercapto groups. Examples of the polythiol compound include polythiol compounds having 2 to 10 mercapto groups in the molecule. Preferred examples include polythiol compounds having 2 to 6 mercapto groups in the molecule. More preferred examples include polythiol compounds having 3 to 4 mercapto groups in the molecule.

[0023] The polythiol compound will be specifically described below. Examples of the polythiol compound include: (a) Polythiol compounds containing hydrocarbon structures (C 2-20 aliphatic polythiols such as alkane polythiol, aromatic aliphatic polythiols such as xylylene dithiol, polythiols obtained by substituting halogen atoms of halohydrin adducts of alcohols with mercapto groups, polythiol compounds comprising hydrogen sulfide reaction products of polyepoxide compounds, etc. (b) a polythiol compound containing an ether structure represented by formula (1), and (c) A polythiol compound having an ester structure represented by formula (2): In formulas (1) and (2), R 1 and R 2 are independently a hydrogen atom or C 1-10 represents an alkyl group, m is 0, 1 or 2, and p is 0 or 1. 2-20 " and "C 1-10 " means that the number of carbon atoms is 2 to 20 and 1 to 10, respectively (the same applies hereinafter).

[0024] [ka]

[0025] Among these polythiol compounds (a) to (c), preferred compounds include the polythiol compound (b) containing an ether structure and the polythiol compound (c) containing an ester structure, and more preferred is the polythiol compound (c) containing an ester structure.

[0026] Examples of the polythiol compound (a) containing a hydrocarbon structure include 2,5-hexanedithiol, 2,9-decanedithiol, and 1,4-bis(1-mercaptoethyl)benzene.

[0027] Examples of the polythiol compound (b) containing an ether structure include compounds containing a structure such as a 2-mercaptoethyl ether group, a 2-mercaptopropyl ether group, a 3-mercaptopropyl ether group, a 2-mercaptobutyl ether group, a 3-mercaptobutyl ether group, a 4-mercaptobutyl ether group, a 5-mercaptopentyl ether group, or a 5-mercaptohexyl ether group.

[0028] The polythiol compound (c) containing an ester structure includes a compound produced by esterifying a mercapto group-containing carboxylic acid, which is a compound having a hydrogen atom bonded to the left end of the structure of formula (2), with a polyhydric alcohol. The term "polyhydric alcohol" refers to a compound containing two or more hydroxyl groups.

[0029] Specific examples of the mercapto group-containing carboxylic acid, which is a compound having a hydrogen atom bonded to the left terminal of the structure of formula (2), include thioglycolic acid, 2-mercaptopropionic acid, 3-mercaptobutyric acid, 2-mercaptoisobutyric acid, 3-mercaptoisobutyric acid, 3-mercaptopropionic acid, 3-mercapto-3-phenylpropionic acid, and 3-mercapto-3-methylbutyric acid, and are preferably 3-mercaptobutyric acid, 3-mercapto-3-phenylpropionic acid, and 3-mercapto-3-methylbutyric acid. More preferably, is 3-mercaptobutyric acid.

[0030] Specific examples of polyhydric alcohols used in the esterification with the mercapto group-containing carboxylic acid include C 2-20 Alkylene glycol (C 2-10Alkylene groups are preferred, and the carbon chain may be branched. Examples include ethylene glycol, trimethylene glycol, 1,2-propylene glycol, 1,2-butanediol, 1,3-butanediol, 2,3-butanediol, tetramethylene glycol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 1,12-dodecanediol, cyclohexane-1,4-dimethanol, and hydrogenated bisphenol A. ), diethylene glycol, poly(oxyalkylene) glycol, glycerin, triethylene glycol, polyethylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, polytetramethylene ether glycol, trimethylolpropane, ditrimethylolpropane, pentaerythritol, dipentaerythritol, cyclohexanediol, cyclohexanedimethanol, norbornene dimethanol, norbornane dimethanol, polycarbonate diol, hydroxy-terminated polysilicone, polyol containing an aromatic ring, tris-2-hydroxyethyl isocyanurate, 2,2-bis[4-(2-hydroxyethyloxy)phenyl]propane, hydrogenated bisphenol A, 4,4'-(9-fluorenylidene)bis(2-phenoxyethanol), cyclohexane-1,4-dimethanol ethylene oxide adduct, hydrogenated bisphenol A ethylene oxide adduct, cyclohexane-1,4-dimethanol propylene oxide adduct, hydrogenated bisphenol A propylene oxide adduct, and the like.

[0031] Preferred polyhydric alcohols include alkylene glycols having two carbon atoms in the alkylene main chain, such as ethylene glycol, 1,2-propylene glycol, and 1,2-butanediol, trimethylolpropane, polycarbonate diol, cyclohexanediol, cyclohexanedimethanol, and 1,5-pentanediol. Examples of the aromatic ring-containing polyols include 2,2-bis[4-(2-hydroxyethyloxy)phenyl]propane, 4,4'-(9-fluorenylidene)diphenol, and 4,4'-(9-fluorenylidene)bis(2-phenoxyethanol).

[0032] Examples of the polythiol compound (c) containing these ester structures include polythiol compounds represented by formula (3) and formula (4). In formula (3), R 3 ~R 6 are independently a hydrogen atom or C 1-10 represents an alkyl group. In formulas (3) and (4), L-(CO)-O- represents the structure represented by formula (2) above.

[0033] [ka]

[0034] R in Equation (3) 3 ~R 6 C 1-10 The alkyl group may be a straight or branched C 1-3 An alkyl group is preferred. 1-10 Specific examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, and an isopropyl group, and among these, a methyl group and an ethyl group are preferred. 3 is a hydrogen atom, a methyl group, or an ethyl group, and R 4 ~R 6 A polythiol compound in which all of are hydrogen atoms is particularly preferred.

[0035] Formula (3) orSpecific examples of the polythiol compound represented by formula (4) include ethylene glycol bis(3-mercaptobutyrate), propylene glycol bis(3-mercaptobutyrate), diethylene glycol bis(3-mercaptobutyrate), butanediol bis(3-mercaptobutyrate), octanediol bis(3-mercaptobutyrate), trimethylolpropane tris(3-mercaptobutyrate), pentaerythritol tetrakis(3-mercaptobutyrate), dipentaerythritol hexakis(3-mercaptobutyrate), bis(3-mercaptobutyrate), 1,3-butanediol bis(3-mercaptobutyrate), 1,4-butanediol bis(3-mercaptobutyrate), neopentyl glycol bis(3-mercaptobutyrate), 1,6-hexanediol bis(3-mercaptobutyrate), 1,8-octanediol bis(3-mercaptobutyrate), 1,9-nonanediol bis(3-mercaptobutyrate), cyclohexane-1,4-dimethanol bis(3-mercaptobutyrate), diethylene glycol bis(3-mercaptobutyrate), triethylene glycol Polyethylene glycol bis(3-mercaptobutyrate), dipropylene glycol bis(3-mercaptobutyrate), tripropylene glycol bis(3-mercaptobutyrate), polypropylene glycol bis(3-mercaptobutyrate), polytetramethylene ether glycol bis(3-mercaptobutyrate), cyclohexane-1,4-dimethanol ethylene oxide adduct bis(3-mercaptobutyrate), hydrogenated bisphenol A ethylene oxide adduct bis(3- bis(3-mercaptobutyrate), cyclohexane-1,4-dimethanol propylene oxide adduct bis(3-mercaptobutyrate), hydrogenated bisphenol A propylene oxide adduct bis(3-mercaptobutyrate), glycerol tris(3-mercaptobutyrate), diglycerol tetrakis(3-mercaptobutyrate), trimethylolpropane tris(3-mercaptobutyrate), ditrimethylolpropane tetrakis(3-mercaptobutyrate), pentaerythritol tetrakis(3-mercaptobutyrate),Dipentaerythritol hexakis(3-mercaptobutyrate), ethylene glycol bis(2-mercaptopropionate), propylene glycol bis(2-mercaptopropionate), diethylene glycol bis(2-mercaptopropionate), butanediol bis(2-mercaptopropionate), octanediol bis(2-mercaptopropionate), trimethylolpropane tris(2-mercaptopropionate), pentaerythritol tetrakis(2-mercaptopropionate), dipentaerythritol Hexakis(2-mercaptopropionate), ethylene glycol bis(3-mercaptoisobutyrate), propylene glycol bis(3-mercaptoisobutyrate), diethylene glycol bis(3-mercaptoisobutyrate), butanediol bis(3-mercaptoisobutyrate), octanediol bis(3-mercaptoisobutyrate), trimethylolpropane tris(3-mercaptoisobutyrate), pentaerythritol tetrakis(3-mercaptoisobutyrate), dipentaerythritol hexakis(3-mercaptoisobutyrate) toisobutyrate), ethylene glycol bis(2-mercaptoisobutyrate), propylene glycol bis(2-mercaptoisobutyrate), diethylene glycol bis(2-mercaptoisobutyrate), butanediol bis(2-mercaptoisobutyrate), octanediol bis(2-mercaptoisobutyrate), trimethylolpropane tris(2-mercaptoisobutyrate), pentaerythritol tetrakis(2-mercaptoisobutyrate), dipentaerythritol hexakis(2-mercapto ... ethylene glycol bis(4-mercaptovalerate), propylene glycol bis(4-mercaptoisovalerate), diethylene glycol bis(4-mercaptovalerate), butanediol bis(4-mercaptovalerate), octanediol bis(4-mercaptovalerate), trimethylolpropane tris(4-mercaptovalerate), pentaerythritol tetrakis(4-mercaptovalerate), dipentaerythritol hexakis(4-mercaptovalerate), ethylene glycol bis(3-mercaptovalerate),Propylene glycol bis(3-mercaptovalerate), diethylene glycol bis(3-mercaptovalerate), butanediol bis(3-mercaptovalerate), octanediol bis(3-mercaptovalerate), trimethylolpropane tris(3-mercaptovalerate), pentaerythritol tetrakis(3-mercaptovalerate), dipentaerythritol hexakis(3-mercaptovalerate), hydrogenated bisphenol A bis(3-mercaptobutyrate), bisphenol A dihydroxyethyl ether-3-mercaptobutyrate, 4,4'-(9-fluorenylidene)bis(2-phenoxyethyl(3-mercaptobutyrate)), ethylene glycol bis(3-mercapto-3 -phenylpropionate), propylene glycol bis(3-mercapto-3-phenylpropionate), diethylene glycol bis(3-mercapto-3-phenylpropionate), butanediol bis(3-mercapto-3-phenylpropionate), octanediol bis(3-mercapto-3-phenylpropionate), trimethylolpropane tris(3-mercapto-3-phenylpropionate), tris-2-(3-mercapto-3-phenylpropionate)ethyl isocyanurate, pentaerythritol tetrakis(3-mercapto-3-phenylpropionate), dipentaerythritol hexakis(3-mercapto-3-phenylpropionate), ethylene glycol bis, (bis(thioglycolate), trimethylene glycol bis(thioglycolate), propylene glycol bis(thioglycolate), 1,3-butanediol bis(thioglycolate), 1,4-butanediol bis(thioglycolate), neopentyl glycol bis(thioglycolate), 1,6-hexanediol bis(thioglycolate), 1,8-octanediol bis(thioglycolate), 1,9-nonanediol bis(thioglycolate), cyclohexane-1,4-dimethanol bis(thioglycolate), diethylene glycol bis(thioglycolate) glycol bis(thioglycolate), triethylene glycol bis(thioglycolate), polyethylene glycol bis(thioglycolate), dipropylene glycol bis(thioglycolate), tripropylene glycol bis(thioglycolate), polypropylene glycol bis(thioglycolate), polytetramethylene ether glycol bis(thioglycolate), cyclohexane-1,4-dimethanol ethylene oxide adduct bis(thioglycolate), hydrogenated bisphenol A ethylene oxide adduct bis(thioglycolate), cyclohexane-1, 4-Dimethanol propylene oxide adduct bis(thioglycolate), hydrogenated bisphenol A propylene oxide adduct bis(thioglycolate), glycerol tris(thioglycolate), diglycerol tetrakis(thioglycolate), trimethylolpropane tris(thioglycolate), ditrimethylolpropane tetrakis(thioglycolate), pentaerythritol tetrakis(thioglycolate), dipentaerythritol hexakis(thioglycolate), ethylene glycol bis(3-mercaptopropionate), methylene glycol bis(3-mercaptopropionate), propylene glycol bis(3-mercaptopropionate), 1,3-butanediol bis(3-mercaptopropionate), 1,4-butanediol bis(3-mercaptopropionate), neopentyl glycol bis(3-mercaptopropionate), 1,6-hexanediol bis(3-mercaptopropionate), 1,8-octanediol bis(3-mercaptopropionate), 1,9-nonanediol bis(3-mercaptopropionate), cyclohexane-1,4-Dimethanol bis(3-mercaptopropionate), diethylene glycol bis(3-mercaptopropionate), triethylene glycol bis(3-mercaptopropionate), polyethylene glycol bis(3-mercaptopropionate), dipropylene glycol bis(3-mercaptopropionate), tripropylene glycol bis(3-mercaptopropionate), polypropylene glycol bis(3-mercaptopropionate), polytetramethylene ether glycol bis(3-mercaptopropionate), cyclohexane-1,4-dimethanol ethylene oxide adduct bis(3-mercaptopropionate), hydrogenated bisphenol A ethylene oxide Examples include the side adduct bis(3-mercaptopropionate), the cyclohexane-1,4-dimethanol propylene oxide adduct bis(3-mercaptopropionate), the hydrogenated bisphenol A propylene oxide adduct bis(3-mercaptopropionate), glycerol tris(3-mercaptopropionate), diglycerol tetrakis(3-mercaptopropionate), trimethylolpropane tris(3-mercaptopropionate), ditrimethylolpropane tetrakis(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptopropionate), and dipentaerythritol hexakis(3-mercaptopropionate).

[0036] Among these polythiol compounds, polythiol compounds containing two or more 3-mercaptobutyrate groups are preferred, with polyethylene glycol bis(3-mercaptobutyrate), pentaerythritol tetrakis(3-mercaptobutyrate), dipentaerythritol hexakis(3-mercaptobutyrate), etc. being particularly preferred. Specific examples of preferred polythiol compounds have structures shown in the following formulas (5) to (14). In formula (14), q is an integer of 1 to 10.

[0037] [ka]

[0038] [ka]

[0039] [ka]

[0040] The polythiol compound may be a compound other than the above-mentioned polythiol compound (a) containing a hydrocarbon structure, polythiol compound (b) containing an ether structure, and polythiol compound (c) containing an ester structure. Examples of the polythiol compound that may be used include phthalic acid di(1-mercaptoethyl ester), phthalic acid di(2-mercaptopropyl ester), phthalic acid di(3-mercaptobutyl ester), and phthalic acid di(3-mercaptoisobutyl ester).

[0041] Preferred polythiol compounds include compounds having a secondary mercapto group, i.e., secondary thiol compounds. Secondary thiol compounds have superior storage stability compared to primary thiol compounds. Furthermore, sealants produced using the photocurable sealant material of this embodiment have superior sealing properties compared to conventionally known photocurable sealants. When a polythiol compound having a secondary mercapto group is used, the photocurable sealant material of this embodiment has excellent application stability during application and excellent sealing properties. In particular, excellent properties can be stably obtained with respect to hardness and flexibility. The reason for this is presumably that, for example, steric hindrance around the mercapto group favorably adjusts the balance between the radical reaction and the thermal addition reaction in the ene-thiol reaction.

[0042] The amount of polythiol compound used is an amount such that the ratio of the total number of (meth)acryloyl groups contained in both the second component (an oligomer having a (meth)acryloyl group) and the third component (a monomer having a (meth)acryloyl group) to the total number of mercapto groups in the first component is 100:5n to 100:25n (n is the number of mercapto groups in one molecule of the polythiol compound). Preferably, the amount is such that the ratio is 100:7n to 100:20n, and more preferably, the amount is such that the ratio is 100:9n to 100:17n.

[0043] The photocurable sealing material is In addition to the first component, the second component and the third component are included; and Further comprising a fourth component and / or a fifth component, the second component is an oligomer having a (meth)acryloyl group and a weight average molecular weight of 1,000 to 30,000, the third component is a monomer having a (meth)acryloyl group, the fourth component is a photoradical polymerization initiator, The fifth component is a viscosity modifier, The third component is contained in an amount of 5 to 100 parts by mass relative to 100 parts by mass of the second component, The ratio of the total number of (meth)acryloyl groups contained in both the second component and the third component to the total number of mercapto groups in the first component is preferably 100:5n to 100:25n, where n is the number of mercapto groups in one molecule of the polythiol compound. Here, "(meth)acryloyl group" means an acryloyl group or a methacryloyl group, as commonly used in the technical field.

[0044] The photocurable sealant material preferably further contains a carbodiimide compound as a sixth component in an amount of 0.1 to 15 parts by mass per 100 parts by mass of the second component. Each component will now be described.

[0045] <Second component: oligomer having a (meth)acryloyl group and a weight-average molecular weight of 1,000 to 30,000> The weight-average molecular weight of the second component oligomer is preferably 1,000 to 30,000, more preferably 2,000 to 25,000, even more preferably 3,000 to 25,000, still more preferably 4,000 to 22,000, and particularly preferably 5,000 to 18,000. The weight-average molecular weight can be measured, for example, by gel permeation chromatography (GPC). The second component oligomer is preferably an oligomer having at least two (meth)acrylate groups in the molecule. The number of (meth)acrylate groups in one molecule of the second component oligomer is, for example, 2 to 10, preferably 2 to 6, more preferably 2 to 4, and particularly preferably 2. Here, the term "(meth)acrylate group" refers to an acrylate group or a methacrylate group, as commonly used in the art.

[0046] Examples of the oligomer of the second component include urethane-based (meth)acrylate oligomers, polyester-based (meth)acrylate oligomers, polyether-based (meth)acrylate oligomers, (meth)acrylic (meth)acrylate oligomers, epoxy-based (meth)acrylate oligomers, conjugated diene polymer-based (meth)acrylate oligomers such as polybutadiene oligomers, and silicone (meth)acrylate oligomers, as well as hydrogenated products thereof.

[0047] The term "urethane-based (meth)acrylate oligomer" refers to a (meth)acrylate oligomer containing a urethane bond. Examples of urethane-based (meth)acrylate oligomers include oligomers obtained by reacting a polyol such as a polyether polyol, a polyester polyol, or a carbonate diol with a polyisocyanate to obtain a polyurethane oligomer, and then esterifying the polyurethane oligomer with (meth)acrylic acid. Here, "(meth)acrylic acid" refers to acrylic acid or methacrylic acid, as commonly used in the art.

[0048] The polyester (meth)acrylate oligomer refers to a (meth)acrylate oligomer containing an ester bond. Examples of the polyester (meth)acrylate oligomer include an oligomer obtained by condensing a polycarboxylic acid with a polyhydric alcohol or by adding a polycarboxylic acid alkylene oxide to obtain a polyester oligomer having hydroxyl groups at both ends, and then esterifying the hydroxyl groups with (meth)acrylic acid.

[0049] The polyether-based (meth)acrylate oligomer refers to a (meth)acrylate oligomer containing an ether bond, such as an oligomer obtained by esterifying the hydroxyl group of a polyether polyol with (meth)acrylic acid.

[0050] Examples of (meth)acrylic (meth)acrylate oligomers include telechelic polyacrylates with highly controlled structures obtained by atom transfer radical polymerization (ATRP). Here, "(meth)acrylic" means acrylic or methacrylic, as commonly used in the art.

[0051] The epoxy (meth)acrylate oligomer refers to a (meth)acrylate oligomer containing an epoxy group. Examples of the epoxy (meth)acrylate oligomer include a bisphenol-type epoxy resin having a relatively low weight-average molecular weight. or Examples of such oligomers include those obtained by esterifying the oxirane ring of a novolac epoxy resin with (meth)acrylic acid. Epoxy (meth)acrylate oligomers also include carboxyl-modified epoxy acrylate oligomers obtained by partially modifying the epoxy (meth)acrylate oligomer with a dicarboxylic acid anhydride.

[0052] The conjugated diene polymer (meth)acrylate oligomer refers to an oligomer obtained by esterifying a conjugated diene polymer with (meth)acrylic acid. Examples of the conjugated diene polymer (meth)acrylate oligomer include SBR diacrylate obtained by esterifying a liquid styrene-butadiene copolymer with acrylic acid, polyisoprene diacrylate obtained by esterifying polyisoprene with acrylic acid, polybutadiene acrylate obtained by esterifying polybutadiene with acrylic acid, and polybutadiene acrylate obtained by reacting a (meth)acrylate having an isocyanate group with 1,2-polybutadiene having a hydroxyl group at the molecular terminal.

[0053] The silicone (meth)acrylate oligomer refers to a (meth)acrylate oligomer containing a siloxane bond, such as an ester compound of a hydroxyl group of an alcoholic siloxane compound with acrylic acid.

[0054] The oligomer of the second component may be used singly or in combination of two or more. A preferred oligomer of the second component is a urethane-based (meth)acrylate oligomer, for example, a urethane-based polyester (meth)acrylate oligomer. The urethane-based polyester (meth)acrylate oligomer is obtained by reacting a polyether polyol with a polyisocyanate to obtain a polyurethane oligomer, and then esterifying the polyurethane oligomer with (meth)acrylic acid.

[0055] In the production of a urethane-based (meth)acrylate oligomer having two (meth)acryloyl groups, which is a preferred oligomer of the second component, examples of polyether diols, polyester diols, and carbonate diols having two hydroxyl groups that can be used include the following:

[0056] Examples of polyether diols include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyhexamethylene glycol, and polyether diols in which ethylene oxide, propylene oxide, or the like is added to 1,3-butylene glycol, 1,4-butylene glycol, neopentyl glycol, cyclohexanedimethanol, 2,2-bis(4-hydroxycyclohexyl)propane, bisphenol A, or the like.

[0057] Examples of polyester diols include compounds in which ethylene oxide or propylene oxide is added to polyethylene glycol, polypropylene glycol, polytetramethylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, 1,6-hexanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, 2,2-bis(4-hydroxycyclohexyl)propane, bisphenol A, or the like, and polyester diols obtained by reacting an alcohol to which ε-caprolactone is added with a dicarboxylic acid or anhydride such as adipic acid, sebacic acid, azelaic acid, or dodecanedicarboxylic acid.

[0058] Examples of carbonate diols include carbonate diols obtained by reacting diaryl carbonates or dialkyl carbonates such as diphenyl carbonate, bis-chlorophenyl carbonate, dinaphthyl carbonate, phenyl-toluyl carbonate, phenyl-chlorophenyl carbonate, 2-tolyl-4-tolyl carbonate, dimethyl carbonate, and diethyl carbonate with diols such as 1,6-hexanediol, neopentyl glycol, 1,4-butanediol, 1,8-octanediol, 1,4-cyclohexanedimethanol, 2-methylpropanediol, dipropylene glycol, and dibutylene glycol.

[0059] <Third component: Monomer having a (meth)acryloyl group> Examples of the monomer having a (meth)acryloyl group in this embodiment include a (meth)acrylate monomer and a (meth)acrylamide monomer, which will be described in detail below.

[0060] (Meth)acrylate Monomers The (meth)acrylate monomer may be a (meth)acrylate monomer having at least one (meth)acryloyl group in the molecule. Specific examples include a monofunctional monomer having one (meth)acryloyl group, a bifunctional monomer having two (meth)acryloyl groups, a trifunctional monomer having three (meth)acryloyl groups, and a tetrafunctional monomer having four (meth)acryloyl groups. The (meth)acrylate monomer may also be a (meth)acrylate monomer having at least one polar group selected from the group consisting of a hydroxyl group, a carboxyl group, and an amino group.

[0061] Examples of monofunctional monomers include methyl methacrylate, butyl methacrylate, 2-phenoxyethyl acrylate, ethoxylated 2-phenoxyethyl acrylate, 2-(2-ethoxyethoxy)ethyl acrylate, EO-modified phenol acrylate, cyclic trimethylolpropane, acrylic acid formal, β-carboxyethyl acrylate, lauryl methacrylate, isooctyl acrylate, stearyl methacrylate, isodecyl acrylate, isostearyl acrylate, and isobornyl methacrylate. acrylate, benzyl acrylate, hydroxypivalyl hydroxypivalate diacrylate, ethoxylated 1,6-hexanediol diacrylate, dipropylene glycol diacrylate, tricyclodecane dimethanol diacrylate, ethoxylated dipropylene glycol diacrylate, neopentyl glycol diacrylate, propoxylated neopentyl glycol diacrylate, ethoxylated bisphenol-A dimethacrylate, 2-methyl-1,3-propanediol diacrylate, ethoxylated 2-methyl butyl-1,3-propanediol diacrylate, 2-butyl-2-ethyl-1,3-propanediol diacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, 2-hydroxyethyl methacrylate phosphate, tris(2-hydroxyethyl) isocyanurate triacrylate, pentaerythritol triacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, trimethylolpropane trimethacrylate acrylate, pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, di-trimethylolpropane tetraacrylate, propoxylated pentaerythritol tetraacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, methacrylate, hydroxyethyl acrylate (HEA), 2-hydroxyethyl methacrylate (HEMA), tripropylene glycol dimethacrylate, 1,4-butanediol dimethacrylate, 1,Examples of suitable acrylates include 6-hexanediol dimethacrylate, arylated cyclohexyl dimethacrylate, isocyanurate dimethacrylate, ethoxylated trimethylolpropane trimethacrylate, propoxylated glycerol trimethacrylate, trimethylolpropane trimethacrylate, tris(acryloxyethyl)isocyanurate, 4-hydroxybutyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, and combinations of two or more thereof.

[0062] Difunctional monomers include, for example, 1,6-hexanediol diacrylate, bisphenol A ethoxylated acrylate, polyethylene glycol diacrylate (200-600), tripropylene glycol diacrylate, neopentyl glycol propoxylate (2), ethoxylated (2) neopentyl glycol diacrylate, dipropylene glycol diacrylate, trimethylolpropane ethoxylated (3) methyl ether diacrylate, and combinations of two or more thereof.

[0063] Trifunctional monomers include, for example, trimethylolpropane triacrylate, trimethylolpropane propoxylated (5-20) triacrylate, propoxylated (4) glycerol triacrylate, ethoxylated (3) trimethylolpropane triacrylate, propoxylated pentaerythritol triacrylate, and combinations of two or more thereof.

[0064] Examples of tetrafunctional monomers include ditrimethylolpropane tetraacrylate, dipentaerythritol monohydroxypentaacrylate, and combinations of two or more thereof.

[0065] The (meth)acrylate monomer may be used alone or in combination of two or more. Preferred (meth)acrylate monomers include monofunctional monomers. As the (meth)acrylate monomer, a combination of a monofunctional monomer and a bifunctional monomer is also preferred. More preferred are monofunctional monomers.

[0066] (Meth)acrylamide monomer The (meth)acrylamide monomer includes a (meth)acrylamide monomer represented by CH2=CX(CO)NR2 (X represents a hydrogen atom or a methyl group, and R may each independently represent a linear substituent, or two Rs may be joined together to form a cyclic substituent). As commonly used in the technical field, "(meth)acrylamide monomer" refers to an acrylamide monomer or a methacrylamide monomer. Examples of the (meth)acrylamide monomer include a (meth)acryloylmorpholine monomer and a dimethylacrylamide monomer represented by the following formula (15). In formula (15), X represents a hydrogen atom or methyl. The (meth)acrylamide monomer preferably includes a (meth)acryloylmorpholine monomer. Preferably, the (meth)acryloylmorpholine monomer includes an acryloylmorpholine monomer.

[0067] [ka]

[0068] The amount of the (meth)acryloyl group-containing monomer used is preferably in the range of 5 to 100 parts by mass per 100 parts by mass of the (meth)acryloyl group-containing oligomer, which is the second component. By using an amount in this range, the viscosity of the photocurable sealant material of this embodiment is reduced, and the flexibility of the photocurable sealant material can be further improved. A more preferred amount of the (meth)acryloyl group-containing monomer used is in the range of 10 to 80 parts by mass, and even more preferably in the range of 40 to 70 parts by mass, per 100 parts by mass of the second component. Depending on the application of the photocurable sealant material of this embodiment, the type and amount of the (meth)acryloyl group-containing monomer can be adjusted as needed to achieve the desired properties, such as viscosity and flexibility.

[0069] <Fourth component: Photoradical polymerization initiator> As the photoradical polymerization initiator, for example, an intramolecular cleavage type and / or hydrogen abstraction type photoradical polymerization initiator can be used. Preferably, an intramolecular cleavage type photoradical polymerization initiator is used. As the radical ultraviolet polymerization initiator, known ones can be suitably used. Specifically, benzoins such as benzoin, benzoin methyl ether, and benzoin ethyl ether and their alkyl ethers; acetophenones such as acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 4-(1-t-butyldioxy-1-methylethyl)acetophenone, and diethoxyacetophenone; anthraquinones such as 2-methylanthraquinone, 2-amylanthraquinone, 2-t-butylanthraquinone, and 1-chloroanthraquinone; thioxanthones such as 2,4-dimethylthioxanthone, 2,4-diisopropylthioxanthone, and 2-chlorothioxanthone; ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal; benzophenones such as 4-(1-t-butyldioxy-1-methylethyl)benzophenone and 3,3',4,4'-tetrakis(t-butyldioxycarbonyl)benzophenone; α-Aminoalkylphenones such as [4-(methylthio)phenyl]-2-morpholino-propan-1-one and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone; 1-hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy-1{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one, and 2-hydroxy-2-methyl-1-phenyl-propan-1-one. phenyl glyoxylates such as alkylphenyl glyoxylate; diethoxyacetophenone; acyl phosphine oxides such as 2,4,6-trimethylbenzoylphenylethoxyphosphine oxide; titanocene compounds such as bis(5,2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)-phenyl)titanium, and combinations of two or more of these.

[0070] Preferred photoradical polymerization initiators include intramolecular cleavage type photoradical initiators such as benzoins, ketals, α-hydroxyalkylphenones, α-aminoalkylphenones, acylphosphine oxides, phenyl glyoxylates, acetophenones, and titanocene compounds.

[0071] The amount of the photoradical polymerization initiator added is not particularly limited, but may be, for example, 0.1 to 10 parts by mass relative to 100 parts by mass of the total of the first to third components. The amount added is preferably 0.2 to 5 parts by mass, and more preferably 0.5 to 2 parts by mass, relative to 100 parts by mass of the total of the first to third components.

[0072] <5th ingredient: viscosity adjuster> The viscosity modifier is not particularly limited, but examples thereof include inorganic viscosity modifiers such as white carbon, colloidal silica, silica sand (silica powder), aerosil, diatomaceous earth, hydrophobic calcium carbonate, glass balloons and glass beads, and polyvinylpyrrolidone. These viscosity modifiers may be used alone or in combination of two or more. Preferred viscosity modifiers include inorganic viscosity modifiers.

[0073] The amount of viscosity modifier added is not particularly limited, but may be, for example, 0.1 to 20 parts by mass, and preferably 0.2 to 10 parts by mass, per 100 parts by mass of the total amount of the first to third components.

[0074] <Sixth Component: Carbodiimide Compound> The carbodiimide compound refers to a compound containing a carbodiimide group. The carbodiimide compound acts as a hydrolysis stabilizer (hydrolysis stabilizer) that inhibits the chain reaction of hydrolysis by blocking hydroxyl or carboxyl groups generated by hydrolysis of resins such as polyester. Examples of carbodiimide compounds include monocarbodiimide compounds and polycarbodiimide compounds, which are widely known and either can be used. Carbodiimide compounds are disclosed, for example, in JP-A-09-309871, JP-A-09-249801, JP-A-09-208649, JP-A-09-296097, JP-A-08-081533, JP-A-08-027092, JP-A-09-136869, JP-A-09-124582, JP-A-09-188807, and JP-A-200 Examples of the compounds include those described in JP-A-5-082642, JP-A-2005-053870, JP-A-2012-036392, JP-A-2010-163203, JP-A-2011-174094, WO 2008 / 072514, JP-A-2012-081759, JP-A-2012-052014, and JP-A-2012-007079.

[0075] The polycarbodiimide compound may be, for example, a compound represented by the formula: R 12 -(-N=C=NR 11 -) r -R 13 In the formula, R in the repeating unit 11 are the same or different and are divalent aromatic and / or aliphatic groups, and r is a natural number.

[0076] For aromatic oligomeric carbodiimides or aromatic polymeric carbodiimides, R 11 may be substituted with an aliphatic and / or alicyclic and / or aromatic substituent having at least one carbon atom, and these substituents may have a heteroatom. These substituents may also be substituted at at least one ortho-position of the aromatic group to which the carbodiimide group is bonded.

[0077] R 12 is C1~C 18 Alkyl, C5-C 18 Cycloalkyl, aryl, C7-C 18 Aralkyl, -R 11 -NH-COS-R 14 , -R 11 COOR 14 , -R 11 -OR 14 , -R 11 -N(R 14 )2, -R 11 -SR 14 , -R 11 -OH, -R 11 -NH2, -R 11 -NHR 14 , -R 11 -Epoxy, -R 11 -NCO, -R 11 -NHCONHR 14 , -R 11 -NHCONR 14 R 15 or -R 11 -NHCOOR 16 is.

[0078] R 13 means -N=C=N-aryl, -N=C=N-alkyl, -N=C=N-cycloalkyl, -N=C=N-aralkyl, -NCO, -NHCONHR 14 , -NHCONHR 14 R 15 , -NHCOOR 16 , -NHCOS-R 14 , -COOR 14 , -OR 14 , Epoxy, -N(R 14 )2, -SR 14 , -OH, -NH2, -NHR 14 is.

[0079] R 14 and R 15 are the same or different, C1 to C 20 Alkyl, C3-C 20 Cycloalkyl, C7-C 18Aralkyl, oligo / polyethylene glycols and / or oligo / polypropylene glycols.

[0080] R 16 is the above R 14 or is a polyester group or a polyamide group.

[0081] When the polycarbodiimide compound is an oligomeric carbodiimide, r is an integer of 1 to 5. When the polycarbodiimide compound is a polymeric carbodiimide, r is an integer of more than 5.

[0082] A preferred polycarbodiimide compound is an aliphatic polycarbodiimide compound having multiple -N=C=N- groups. A more preferred example is a linear aliphatic polymer compound. Specific examples include an aliphatic polycarbodiimide compound (Elastostab H01, manufactured by Nisshinbo Chemical Inc.).

[0083] The amount of the carbodiimide compound used is, for example, in the range of 0.1 to 15 parts by mass per 100 parts by mass of the second component, the oligomer having a (meth)acryloyl group. amount The amount is preferably 0.5 to 12 parts by mass, and more preferably 1 to 10 parts by mass, relative to 100 parts by mass of the second component oligomer having a (meth)acryloyl group.

[0084] When a carbodiimide compound is added to the photocurable sealant material according to this embodiment, it remains stable for more than six months, demonstrating excellent storage stability. Furthermore, there is little adverse effect on the photocurability and the physical properties of the resulting sealant. The inventors speculate that the storage stabilization effect of the carbodiimide compound occurs through the following mechanism. Ene-thiol-based photocurable resin materials deteriorate in quality due to the reaction between the active mercapto groups and double bonds contained therein, which progresses during storage, resulting in gelation. However, when a carbodiimide compound is added to the resin material, the carbodiimide compound preferentially bonds to and inactivates the most active mercapto groups, thereby suppressing quality degradation due to gelation and providing a storage stabilization effect.

[0085] The carbodiimide compound can also be used as a stabilizer for the ene-thiol-based photocurable resin material. The amount of the carbodiimide compound added to the ene-thiol-based photocurable resin material can be appropriately changed.

[0086] <7th ingredient: sensitizer> A sensitizer can be added to the photocurable sealing material according to the present embodiment so that it can be photocured not only by ultraviolet light but also by visible light and near-infrared light. Examples of the sensitizer include unsaturated ketones such as chalcone derivatives and dibenzalacetone, 1,2-diketone derivatives such as camphorquinone, benzoin derivatives, fluorene derivatives, naphthoquinone derivatives, anthraquinone derivatives, xanthene derivatives, thioxanthene derivatives, xanthone derivatives, thioxanthone derivatives, coumarin derivatives, ketocoumarin derivatives, cyanine derivatives, merocyanine derivatives, and oxonol derivatives, polymethine dyes, acridine derivatives, azine derivatives, thiazine derivatives, oxazine derivatives, indoline derivatives, azulene derivatives, azulenium derivatives, sulfur dioxide, and the like. Examples thereof include qualylium derivatives, porphyrin derivatives, tetraphenylporphyrin derivatives, triarylmethane derivatives, tetrabenzoporphyrin derivatives, tetrapyrazinoporphyrazine derivatives, phthalocyanine derivatives, tetraazaporphyrazine derivatives, tetraquinoxalylporphyrazine derivatives, naphthalocyanine derivatives, subphthalocyanine derivatives, pyrylium derivatives, thiopyrylium derivatives, tetraphyrin derivatives, annulene derivatives, spiropyran derivatives, spirooxazine derivatives, thiospiropyran derivatives, metal arene complexes, and organic ruthenium complexes.

[0087] The amount of the sensitizer to be added is not particularly limited, but may be, for example, 0.1 to 10 parts by mass relative to 100 parts by mass of the total amount of the first to third components. The amount to be added is preferably 0.2 to 5 parts by mass, and more preferably 0.5 to 2 parts by mass, relative to 100 parts by mass of the total amount of the first to third components.

[0088] <Other ingredients> Other components may be added to the photocurable sealing material of this embodiment. Examples of other components include thickeners, polymerization inhibitors, pigments, adhesion improvers, antioxidants, curing accelerators, fillers, plasticizers, surfactants, lubricants, antistatic agents, and stabilizers. These components may be added in appropriate amounts depending on the intended purpose.

[0089] <Shore 00 hardness> In the photocurable sealing material according to this embodiment, the sheet after photocuring preferably has a Shore 00 hardness of 5 to 100, more preferably 5 to 90, and even more preferably 5 to 85, at 23°C and a relative humidity of 50 to 60%RH. Having the Shore 00 hardness in this range further improves sealing properties. The Shore 00 hardness can be measured, for example, by a method in accordance with ASTM D 2240.

[0090] (Preparation of light-curable sealing material) The photocurable sealant material of this embodiment can be prepared by mixing a polythiol compound (first component), a (meth)acryloyl group-containing oligomer (second component) having a weight-average molecular weight of 1,000 to 30,000, a (meth)acrylate monomer (third component), a photoradical polymerization initiator (fourth component) and / or a viscosity modifier (fifth component), and optionally a carbodiimide compound (sixth component), a sensitizer (seventh component), and / or other components at room temperature or under heated conditions using a mixer, ball mill, three-roll mill, or other mixing device. The photocurable sealant material can also be prepared by adding a solvent or other diluent, dissolving, and mixing, as needed. Examples of solvents used as diluents include esters such as ethyl acetate, butyl acetate, and isopropyl acetate; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; cyclic ethers such as tetrahydrofuran and dioxane; amides such as N,N-dimethylformamide; aromatic hydrocarbons such as toluene; and halogenated hydrocarbons such as methylene chloride.

[0091] (Method of applying light-curing sealing material) The method for curing the photocurable sealant material of this embodiment is not particularly limited, and can be, for example, by irradiation with energy rays. Examples of energy rays that can be used include electromagnetic waves such as light, and radiation. Specific examples include ultraviolet light, visible light, infrared light, α-rays, β-rays, γ-rays, and electron beams. From the viewpoints of operability, productivity, and cost efficiency, ultraviolet light is preferred. The irradiation time of the energy rays can be appropriately selected depending on the type of energy beam used. Examples of ultraviolet light sources that can be used include ultra-high pressure mercury, metal halide light sources, lasers, and LEDs. When α-rays, β-rays, γ-rays, electron beams, and the like are used, curing can proceed rapidly without the addition of a photoradical polymerization initiator. However, when ultraviolet light is used, it is preferable to add a photoradical polymerization initiator to the photocurable sealant material of this embodiment.

[0092] The application of the photocurable sealing material of this embodiment to a gasket in a housing will be described below. When the housing is made up of two parts that sandwich a gasket, the housing of this embodiment can be manufactured according to the following steps (1) to (4). (1) Apply a light-curing sealing material evenly to the grooves (gasket application areas) of each of the two components; (2) Irradiate each of the two applied components with ultraviolet light or the like to harden the photocurable sealing material and generate a gasket; (3) Incorporating a device to be stored inside as necessary (for example, arranging a "member to be inserted through the housing" such as a cable so as to straddle the photocured curable sealant, and sandwiching the photocured sealant between the two components so that the photocured sealant in the two components faces each other); and (4) Fit the above two parts together.

[0093] In this embodiment, the term "housing" refers to a box that houses a machine or electrical device having some function and its components, and protects the device from impact, pressure, electromagnetic waves, water, dust, light, etc. Examples of the machine or electrical device include electronic products such as mobile phones, digital cameras, and video cameras, home appliances such as refrigerators, air conditioners, and washing machines, and precision instruments such as cameras and watches. When used in a housing, the photocurable sealing material of this embodiment prevents the intrusion of water, pressure, dust, etc., and does not impair the protective effect of the housing as a whole.

[0094] (Properties of light-curing sealing materials) The photocurable sealing material of this embodiment has high self-adhesion, resulting in excellent sealing properties. Furthermore, the photocurable sealing material can be automatically applied to a housing by a robot without using a mold. Therefore, the photocurable sealing material is superior in operability and mass productivity compared to conventional sealing materials. [Example]

[0095] The present invention will be explained in more detail below by showing experimental examples, but the present invention is not limited to these examples.

[0096] (raw materials) The following raw materials were used to prepare the photocurable sealing material. <First component> Polythiol: Karenz MT PE1 (Showa Denko K.K., pentaerythritol tetrakis(3-mercaptobutyrate)) <Second component> Urethane acrylate A: Shiko UV-3000B (Nippon Synthetic Chemical Industry Co., Ltd., weight average molecular weight: 18,000) Urethane acrylate B: Shiko UV-6640B (Nippon Synthetic Chemical Industry Co., Ltd., weight average molecular weight: 5000) <Third component> Acrylic Monomer A: 4-Hydroxybutyl Acrylate (4-HBA) (Osaka Organic Chemical Industry Ltd.) Acrylic Monomer B: Acryloylmorpholine Monomer (ACMO) (KJ Chemical Co., Ltd.) Acrylic Monomer C: New Frontier PHE-2 (Dai-ichi Kogyo Seiyaku Co., Ltd., EO-modified phenol acrylate) Acrylic Monomer D: Isostearyl Acrylate (Osaka Organic Chemical Industry) <Fourth component> Photoradical polymerization initiator: Irgacure 1173 (BASF Japan Ltd., 2-hydroxy-2-methyl-1-phenyl-propan-1-one) <5th component> Viscosity adjuster: Aerosil RY200 (Aerosil, Nippon Aerosil Co., Ltd.) <Sixth ingredient> Carbodiimide compound: ElastoStab H01 (Nisshinbo Chemical Inc.) <Other ingredients> Stabilizer: Hydroquinone (Kishida Chemical Co., Ltd.) (Preparation of photocurable sealing material) Example 1 41 parts by mass of urethane acrylate A (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name: Shikou UV-3000B), 10 parts by mass of urethane acrylate B (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name: Shikou UV-6640B), 25 parts by mass of acrylic monomer A (manufactured by Osaka Organic Chemical Industry Co., Ltd., trade name: 4-HBA), and pentaerythritol tetrakis(3-mercaptobutyrate) having a molecular weight of 544.8 as a polythiol (manufactured by Showa Denko K.K., trade name: Karenz MT). 18 parts by mass of PE1) and 7 parts by mass of a viscosity modifier (manufactured by Nippon Aerosil Co., Ltd., trade name: Aerosil RY200) were uniformly mixed under vacuum using a stirrer, and then 1 part by mass of 2-hydroxy-2-methyl-1-phenyl-propan-1-one (manufactured by BASF Japan Ltd., trade name: Irgacure 1173) as a photoradical polymerization initiator and 0.05 parts by mass of 1,4-benzenediol (manufactured by Kishida Chemical Co., Ltd., trade name: Hydroquinone) as a stabilizer were added, and the mixture was mixed uniformly and degassed using a stirrer to obtain a photocurable sealing material of Example 1.

[0097] <Examples 2 to 8, Comparative Example 1> The photocurable sealing materials of Examples 2 to 8 and the photocurable sealing material of Comparative Example 1 were obtained in the same manner as in Example 1, except that the raw materials were used in the compositions shown in Table 1.

[0098] (Test example) <Preparation of specimen> Each of the photocurable sealing materials obtained in Examples 1 to 8 and Comparative Example 1 was formed into a 1 mm thick sheet on a 100 μm thick PET film. The resulting sheet was then cured by UV irradiation using an electrodeless metal halide lamp type UV irradiation device (manufactured by Heraeus GmbH, product name: Light Hammer 6) (integrated light intensity of UV-A rays: approximately 6000 mJ / cm). 2 The cured sheet was cut into pieces 25 mm wide and 200 mm long, and the cut sheets were placed face-to-face to prepare a specimen. A 10 kg load was applied for 10 seconds. The cumulative light intensity during UV irradiation was measured using a Heraeus UV Power Puck.

[0099] <Evaluation of self-adherence, etc.> Immediately after applying a 10 kg load for 10 seconds, the T-peel strength (self-adhesion strength) of the above specimens was measured using a tensile tester (manufactured by Orientec Co., Ltd. (now A&D Co., Ltd.), product name: RTC-1310A). At the same time, the presence or absence of a laminated interface between the two sheets was confirmed using a digital microscope (magnification: 50x) manufactured by ANMO Electronics Co., Ltd. The test was conducted at a test temperature of 23°C and a peel speed of 300 mm / min. The results are shown in Table 1.

[0100] <Shore 00 hardness evaluation> The Shore 00 hardness of the specimens prepared as described above was measured and evaluated using the following method. According to ASTM D 2240, specimens were prepared by stacking multiple cured sheets of each photocurable sealant material, each approximately 1 mm thick, to a thickness of approximately 6 mm or more. The Shore 00 hardness of the specimens was then measured using a Type 00 durometer (manufactured by Teclock Corporation, product name: GS-754G) in an environment of 23°C and a relative humidity of 50-60% RH. The evaluation results are shown in Table 1.

[0101] [Table 1]

[0102] From the results in Table 1, the sheets obtained from the light-curable sealing materials of Examples 1 to 8 exhibited self-adhesion, with the lamination interface between the two overlapping sheets disappearing, and the self-adhesion strength was 80 to 160 N / 25 mm. Furthermore, the sheets obtained from the light-curable sealing materials of Examples 1 to 8 had a Shore 00 hardness of 15 to 58. The self-adhesion exhibited by the light-curable sealing materials of Examples 1 to 8 was maintained even one day after the specimens were prepared, with the lamination interface between the two sheets disappearing and remaining integrated. On the other hand, the sheet obtained from the light-curable sealing material of Comparative Example 1 had no integration at the lamination interface between the two overlapping sheets, and each sheet was independent. Furthermore, the self-adhesion strength was 0.6 N / 25 mm, and the Shore 00 hardness was 35.

[0103] <Waterproofness test> Using the photocurable sealing materials of Example 1 and Comparative Example 1, a waterproofing test was carried out according to the following procedure.

[0104] (Preparation of specimens for waterproofing evaluation) FIG. 1 is a schematic top cross-sectional view illustrating the configuration of a waterproofing evaluation specimen 10. FIG. 2 is a schematic side cross-sectional view illustrating the configuration of a waterproofing evaluation specimen 10. The preparation of the waterproofing evaluation specimen 10 will be described with reference to FIGS. 1 and 2. Each of the photocurable sealing materials 1a obtained in Example 1 and Comparative Example 1 was applied in a rectangular line (line width and height both 2 mm, 30 mm square) to a polycarbonate plate 2 (1 mm thick, 100 mm square), and then irradiated with UV (integrated light intensity of UV-A rays: approximately 6000 mJ / cm) using an electrodeless metal halide lamp type UV irradiation device (Light Hammer 6 manufactured by Heraeus). 2) and cured (FIG. 1). Two sheets of the photocurable sealant 1a were prepared for each of Example 1 and Comparative Example 1 (hereinafter, these will be referred to as "Substrate A" and "Substrate B"). The integrated light intensity was measured using an illuminance meter (Heraeus UV Power Puck). Next, cobalt chloride paper 3 was placed inside the rectangular frame made of the photocured sealant 1b on Substrate A as an indicator to check water penetration (FIG. 1). Furthermore, cable 4 (0.5 mm diameter, 150 mm long) was placed so as to straddle the photocured sealant 1b on Substrate A. Next, spacers 5 (2 mm thick) were placed in two locations outside the rectangular frame made of the photocured sealant 1b on Substrate A. Substrate B was placed on top of Substrate A so that the surfaces coated with the photocured sealant 1b faced each other, and they were clamped and fixed with clamps 6 (FIG. 2). Thereafter, the photocured sealant 1b on the substrate A and the substrate B was compressed by 50% to obtain a specimen 10 for waterproofing evaluation (FIGS. 1 and 2).

[0105] (Waterproofness evaluation) The specimen was placed in a waterproofing tester (Hamlon Tech, product name: Submerged Airtight Tester HPT8701P01) filled with water, and a predetermined pressure was applied. The color change of the cobalt chloride paper was used as an indicator to determine whether water penetrated into the rectangular frame of the light-curing sealant within two minutes. That is, if the color of the cobalt chloride paper remained blue, the waterproofing test was deemed to have passed; if the color of the cobalt chloride paper changed from blue to red, the waterproofing test was deemed to have failed. The results are shown in Table 2.

[0106] [Table 2]

[0107] These results demonstrate that the self-adhesive light-curing sealing material has excellent waterproof properties.

[0108] Although the embodiments and examples of the present invention have been described above, it is also planned from the beginning that the configurations of the above-described embodiments and examples may be appropriately combined.

[0109] The embodiments and examples disclosed herein are illustrative in all respects and should not be considered limiting. The scope of the present invention is defined by the claims, not by the embodiments and examples described above, and is intended to include any modifications within the scope of the claims and meanings equivalent to the claims. [Explanation of symbols]

[0110] 1a Light-curing sealant, 1b Light-cured sealant, 2 Polycarbonate plate, 3 Cobalt chloride paper, 4 Cable, 5 Spacer, 6 Clamp, 10 Specimen for waterproof evaluation.

Claims

1. A photocurable sealing material containing at least a polythiol compound as a first component, Two sheets of 1 mm thick, 25 mm wide and 200 mm long were prepared using the photocurable sealing material, and were photocured by irradiating them with UV-A rays at an integrated light intensity of 6000 mJ / cm 2. When the two sheets were then laminated together and subjected to a load of 10 kg for 10 seconds, the lamination interface between the two sheets disappeared, and the self-adhesion strength in a T-peel test was 5 N / 25 mm or more when pulled at a peel speed of 300 mm / min. In addition to the first component, a second component and a third component are included; and Further comprising a fourth component and / or a fifth component, the second component is a combination of two or more oligomers having a (meth)acryloyl group and having a weight average molecular weight of 1,000 to 30,000, and the oligomers are urethane-based (meth)acrylate oligomers; the third component is a monomer having a (meth)acryloyl group, the fourth component is a photoradical polymerization initiator, The fifth component is a viscosity modifier, The third component is contained in an amount of 5 to 100 parts by mass relative to 100 parts by mass of the second component, a ratio of the total number of (meth)acryloyl groups contained in both the second component and the third component to the total number of mercapto groups in the first component is 100:5n to 100:25n (n is the number of mercapto groups in one molecule of the polythiol compound).

2. 2. The photocurable sealing material according to claim 1, wherein the self-adhesive strength is 1000 N / 25 mm or less when pulled at a peel rate of 300 mm / min.

3. 3. The photocurable sealing material according to claim 1, wherein the Shore 00 hardness of the sheet after photocuring is 5 to 100 in an environment of 23°C and a relative humidity of 50 to 60% RH.

4. The third component is a (meth)acrylate monomer selected from the group consisting of a monofunctional monomer having one (meth)acryloyl group, a difunctional monomer having two (meth)acryloyl groups, a trifunctional monomer having three (meth)acryloyl groups, and a tetrafunctional monomer having four (meth)acryloyl groups, and the monofunctional monomer is methyl methacrylate, butyl methacrylate, ethoxylated 2-phenoxyethyl acrylate, 2-(2-ethoxyethoxy)ethyl acrylate, cyclic trimethylolpropane, acrylic acid formal, β-carboxyethyl acrylate, lauryl methacrylate, isooctyl Acrylates, stearyl methacrylate, isodecyl acrylate, benzyl acrylate, hydroxypivalyl hydroxypivalate diacrylate, ethoxylated 1,6-hexanediol diacrylate, dipropylene glycol diacrylate, tricyclodecane dimethanol diacrylate, ethoxylated dipropylene glycol diacrylate, neopentyl glycol diacrylate, propoxylated neopentyl glycol diacrylate, ethoxylated bisphenol-A dimethacrylate, 2-methyl-1,3-propanediol diacrylate, ethoxylated 2-methyl-1,3-propanediol diacrylate, 2-butyl-2-ethyl-1,3-propanediol diacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, 2-hydroxyethyl methacrylate phosphate, tris(2-hydroxyethyl)isocyanurate triacrylate, pentaerythritol triacrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, trimethylolpropane Panthenyl methacrylate, pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, di-trimethylolpropane tetraacrylate, propoxylated pentaerythritol tetraacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, methacrylate, hydroxyethyl acrylate (HEA), 2-hydroxyethyl methacrylate (HEMA), tripropylene glycol dimethacrylate, 1,4-butanediol dimethacrylate, 1,The photocurable sealing material according to any one of claims 1 to 3, wherein the (meth)acrylate monomer is one or more selected from the group consisting of 6-hexanediol dimethacrylate, arylated cyclohexyl dimethacrylate, isocyanurate dimethacrylate, ethoxylated trimethylolpropane trimethacrylate, propoxylated glycerol trimethacrylate, trimethylolpropane trimethacrylate, tris(acryloxyethyl)isocyanurate, 4-hydroxybutyl acrylate, and 2-hydroxy-3-phenoxypropyl acrylate.

5. The photocurable sealing material according to any one of claims 1 to 4, further comprising a carbodiimide compound as a sixth component in an amount of 0.1 to 15 parts by mass per 100 parts by mass of the second component.

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