Moisture-curable adhesive composition

Abstract

To provide a moisture-curing type adhesive composition that contains an organic polymer having a hydrolyzable silyl group and is a curable composition excellent in colorless transparency.SOLUTION: A moisture-curing type adhesive composition includes: a curable resin that is a component (A), has polyoxyalkylene as a main chain, and has a hydrolyzable silyl group represented by a following general formula (1) in a terminal thereof; a curable resin that is a component (B), has a vinyl copolymer as a main chain, and has a hydrolyzable silyl group represented by the following general formula (1) in a molecule; a boron trifluoride complex that is a component (C); and a fluorescent whitening agent that is a component (D). The general formula (1); -SiR1a(OR2)3-n, wherein R1 represents an alkyl group having 1 to 10 carbon atoms, R2 represents an alkyl group having 1 to 6 carbon atoms, and a is 0, 1 or 2.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a moisture-curable adhesive composition that is colorless and highly transparent. [Background technology]

[0002] Resins have the property of being moldable into various shapes, and more complex structures can be formed by bonding resin molded bodies with adhesive compositions, so they are widely used as components for constructing various products. In particular, colorless and transparent resins are widely used for the exterior surfaces of various products because they transmit light and have high design potential.

[0003] In order to combine resins to form complex structures, a method of bonding various types of adherends, including resins, to form structures is widely used, and adhesive compositions are used as a means of bonding. Such adhesive compositions include curable adhesives such as room temperature curable adhesives and heat curable adhesives. Furthermore, moisture-curable adhesives that cure with atmospheric moisture have been proposed and used in the hope of improving workability. The applicant has also proposed a moisture-curable adhesive composition with good usability and adhesive properties (Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5922985 Summary of the Invention [Problem to be solved by the invention]

[0005] When a transparent adherend such as a transparent resin is bonded using an adhesive composition, the adhesive composition becomes transparent through the transparent adherend. If the adhesive composition has a color, the presence of the adhesive composition can be seen through the transparent adherend due to the presence of the color, which can cause a problem of deteriorating the appearance of the adherend, which requires high design quality.

[0006] Furthermore, the adhesive composition may overflow from the edge of the adherend, and if the adhesive composition used has a color, the presence of the adhesive composition can be detected by the presence of the color, which can cause the problem of deteriorating the appearance of the adherend.

[0007] Therefore, adhesive compositions used to bond adherends are required to be more colorless and transparent so that the appearance of the adherends after adhesive curing is not marred by the color of the adhesive composition.

[0008] However, conventional adhesive compositions such as the moisture-curing adhesive proposed in Patent Document 1, when used in large amounts, can have a slight yellowish tint after curing, which can impair the appearance of the adherend. This has led to a demand for further improvements to make adhesive compositions more colorless and transparent.

[0009] Therefore, an object of the present invention is to obtain a moisture-curable adhesive composition that is colorless and highly transparent. [Means for solving the problem]

[0010] The present inventors prepared a moisture-curable adhesive composition that did not contain a chlorinated polyolefin resin in order to obtain a moisture-curable adhesive with excellent colorless transparency that would not impair the appearance of the adherend after bonding. However, although the YI (yellowness index) of this adhesive composition was somewhat reduced, it still exhibited a slight yellowish tint. Furthermore, when an antioxidant commonly used in moisture-curable adhesive compositions was added to the composition, the YI value increased, and the yellowish tint actually increased. Thus, even when components that may be involved in coloring were removed from the moisture-curable adhesive composition, the moisture-curable adhesive composition did not achieve sufficient colorless transparency to prevent the appearance of the adherend after bonding. Furthermore, it was confirmed that the addition of an antioxidant commonly used in moisture-curable adhesive compositions increased the yellowish tint. Therefore, it became clear that new improvements were needed.

[0011] Therefore, the present inventors further conducted various trial and error experiments to solve the above problems. They unexpectedly discovered that a moisture-curable adhesive composition containing a curable resin having a polyoxyalkylene main chain and a terminal hydrolyzable silyl group, a curable resin having a vinyl copolymer main chain and a hydrolyzable silyl group in the molecule, a boron trifluoride complex, and a fluorescent brightening agent can be obtained, leading to the completion of the present invention. The present invention employs the following configuration.

[0012] The first means of the present invention for solving the above problems is a moisture-curable adhesive composition comprising: (A) a curable resin having a polyoxyalkylene main chain at its terminal with a hydrolyzable silyl group represented by the following general formula (1); (B) a curable resin having a vinyl copolymer main chain with a hydrolyzable silyl group represented by the following general formula (1) in the molecule; (C) a boron trifluoride complex; and (D) a fluorescent brightening agent. General formula (1);-SiR 1 a (OR 2 ) 3-n (However, R1 represents an alkyl group having 1 to 10 carbon atoms, and R 2 represents an alkyl group having 1 to 6 carbon atoms, and a is 0, 1 or 2.

[0013] A second aspect of the present invention for solving the above problems is the moisture-curable adhesive composition according to the first aspect of the present invention, characterized in that component (A) has a urethane bond and / or a urea bond in the molecule.

[0014] The third aspect of the present invention for solving the above problems is the moisture-curable adhesive composition according to the first or second aspect of the present invention, characterized in that the cured product has excellent colorless transparency. [Effects of the Invention]

[0015] The present invention provides a new moisture-curable adhesive composition that exhibits excellent colorless transparency and does not impair the appearance of the adherend after adhesive curing. Furthermore, the present invention also provides the effect of facilitating color design of the moisture-curable adhesive composition, since the specific color inherent to the coloring component does not change even when a coloring component is further blended. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to these examples, and various modifications can be made without departing from the spirit of the present invention.

[0017] [About the curable resin (A)] The curable resin, which is the component (A) in the moisture-curable adhesive composition of the present invention, has a main chain of polyoxyalkylene, and the main chain has a terminal group represented by the general formula (1); -SiR 1 a (OR 2 ) 3-n (However, R 1 represents an alkyl group having 1 to 10 carbon atoms, and R 2represents an alkyl group having 1 to 6 carbon atoms, and a is 0, 1 or 2. A curable resin having a hydrolyzable silyl group represented by the following formula is used.

[0018] The curable resin of component (A) can be any known curable resin that has a urethane bond and / or a urea bond in the molecule, a terminal hydrolyzable silyl group represented by general formula (1) (hereinafter simply referred to as "hydrolyzable silyl group"), and a polyoxyalkylene main chain. The curable resin of component (A) can be any known curable resin, including those described in Japanese Patent Publication Nos. 3317353, 3030020, 3343604, JP-A Nos. 2004-518801, 2004-536957, and 2005-501146.

[0019] The hydrolyzable silyl group of the curable resin (component (A))) has an alkoxy group (OR) which is a hydrolyzable group in addition to the bond connected to the main chain of the silicon atom. 2 ) is a functional group to which 1 to 3 hydrolyzable groups (OR 2 ) is an alkoxy group having 1 to 6 carbon atoms (preferably 1 to 3 carbon atoms, more preferably 1 or 2 carbon atoms). 2 The number of a is preferably 3 (a=0) when it is desired to increase the curing rate, and 2 (a=1) or 1 (a=2) when it is desired to impart flexibility to the cured product. The functional group R1 bonded to the remaining bond of the silicon atom represents an alkyl group having 1 to 10 carbon atoms (preferably 1 to 4 carbon atoms, particularly preferably 1 or 2 carbon atoms). When multiple hydrolyzable silyl groups are present in the curable resin (A), these functional groups may be the same or different. Furthermore, the curable resin (A) may contain urethane bonds and / or urea bonds in the molecule. It is believed that the presence of urethane bonds and / or urea bonds in the molecule allows the boron trifluoride complex (C), described below, to function effectively, thereby making it easier for the curable resin to exhibit its curing ability.

[0020] The molecular weight of the curable resin, component (A), is not particularly limited, but is preferably a number-average molecular weight of 1,000 to 80,000, more preferably 1,500 to 60,000, and particularly preferably 2,000 to 40,000. If the molecular weight is below 1,000, the crosslinking density may be too high, resulting in a brittle coating film (cured product), while if the molecular weight exceeds 80,000, the viscosity may increase, resulting in poor workability, requiring large amounts of solvent or plasticizer, which may limit incorporation.

[0021] [About the curable resin (B)] The curable resin, which is the component (B) in the moisture-curable adhesive composition of the present invention, has a main chain that is a vinyl copolymer and has a terminal group represented by the general formula (1);-SiR 1 a (OR 2 ) 3-n (However, R 1 represents an alkyl group having 1 to 10 carbon atoms, and R 2 represents an alkyl group having 1 to 6 carbon atoms, and a is 0, 1, or 2.) is used. Any known curable resin can be used as long as it has such a hydrolyzable silyl group in the molecule and the main chain is a vinyl copolymer.

[0022] The curable resin, which is component (B) used in the moisture-curable adhesive composition of the present invention, is a curable resin that has a hydrolyzable silyl group in the molecule and whose main chain is a vinyl copolymer. The hydrolyzable silyl group of the curable resin of component (B) has, like the hydrolyzable silyl group of the curable resin of component (A), an alkoxy group (OR 2 ) is a functional group to which 1 to 3 hydrolyzable groups (OR 2 ) is an alkoxy group having 1 to 6 carbon atoms (preferably 1 to 3 carbon atoms, more preferably 1 or 2 carbon atoms). 2The number of hydrolyzable silyl groups is preferably 3 (a=0) when it is desired to increase the curing rate, and 2 (a=1) or 1 (a=2) is preferred when it is desired to impart flexibility to the cured product. The functional group R1 bonded to the remaining bond of the silicon atom represents an alkyl group having 1 to 10 carbon atoms (preferably 1 to 4 carbon atoms, particularly preferably 1 or 2 carbon atoms). When multiple hydrolyzable silyl groups are present in the curable resin that is component (B), these functional groups may be the same or different.

[0023] The molecular weight of the curable resin, component (B), is not particularly limited, but is preferably a number-average molecular weight of 1,000 to 80,000, more preferably 1,500 to 60,000, and particularly preferably 2,000 to 40,000. If the molecular weight is below 1,000, the crosslinking density may be too high, resulting in a brittle coating film (cured product), while if the molecular weight exceeds 80,000, the viscosity may increase, resulting in poor workability, requiring large amounts of solvent or plasticizer, which may limit incorporation.

[0024] The curable resin (B) can be synthesized. The curable resin (B) can be synthesized by any conventional method. For example, it can be obtained by copolymerizing a polymerizable vinyl compound (b1) having a hydrolyzable silyl group in its molecule with another polymerizable vinyl compound (b2). The copolymerization conditions are not particularly limited, and general radical polymerization, anionic polymerization, and cationic polymerization methods, as well as the polymerization conditions for these polymerization methods, can be applied. Furthermore, various organic solvents can be used as the reaction solvent during polymerization, or low- or high-molecular-weight or high-molecular-weight curable or non-curable resins that are liquid at room temperature can be used. Among these, the most preferred method is to use the curable resin (A) as a solvent and copolymerize the polymerizable vinyl compound (b1) having a hydrolyzable silyl group in its molecule with the polymerizable vinyl compound (b2) in the curable resin (A). By carrying out a vinyl polymerization reaction in the curable resin (A), the mixed viscosity of the curable resin (A) and the curable resin (B) can be adjusted to a low level, and the reaction solvent removal step that was essential in conventional solution polymerization is no longer necessary, making this an industrially very useful production method. The polymerizable vinyl compound (b1) and the polymerizable vinyl compound (b2) each having a hydrolyzable silyl group in their molecule may be appropriately selected to obtain the desired performance, and one type may be used alone or two or more types may be used in combination.

[0025] Examples of the polymerizable vinyl compound (b1) having a hydrolyzable silyl group in the molecule include, but are not limited to, vinyl methoxysilane, vinyl ethoxysilane, 3-(meth)acryloylpropyl trimethoxysilane, 3-(meth)acryloylpropyl methyl dimethoxysilane, 3-(meth)acryloylmethyl diethoxysilane, p-styryl trimethoxysilane, etc. Among these, 3-methacryloylpropyl trimethoxysilane and 3-methacryloylpropyl methyl dimethoxysilane are most preferred in terms of cost and ease of polymerization reaction.

[0026] The polymerizable vinyl compound (b2) is one or more polymerizable vinyl group-containing monomers selected from acrylic acid compounds, methacrylic acid compounds, acrylonitrile compounds, and styrene compounds. Hereinafter, acrylic acid and methacrylic acid will be referred to as (meth)acrylic acid, and acrylate and methacrylate will be referred to as (meth)acrylate. Specific examples of the polymerizable vinyl compound (b2) include (meth)acrylic acid, methyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, cyclohexyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, isobornyl (meth)acrylate, N,N-dimethylacrylamide, N Examples of suitable acrylamides include, but are not limited to, N-diethylacrylamide, N-isopropylacrylamide, morpholine acrylate, (meth)acrylonitrile, styrene, and α-methylstyrene.

[0027] The blending amount of the polymerizable vinyl compound (b1) having a hydrolyzable silyl group in the molecule is preferably 0.1 to 50 mass%, more preferably 0.5 to 30 mass%, and most preferably 1.0 to 15 mass%, of the total mass of all monomer components constituting the curable resin (B) (the mass of the polymerizable vinyl compound (b1) + the mass of the other polymerizable vinyl compound (b2)), and the compound is copolymerized with the other polymerizable vinyl compound (b2) in such a blending amount.

[0028] When synthesizing the curable resin (B) by copolymerization, a conventionally known chain transfer agent can be used in addition to the constituent monomer components. The use of a chain transfer agent not only controls the molecular weight of the curable resin (B), but also allows for the adjustment of the viscosity of the curable resin (B). Examples of chain transfer agents include, but are not limited to, mercapto compounds such as n-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, and thiophenol; mercaptosilane compounds such as γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, γ-mercaptopropyltriethoxysilane, and γ-mercaptopropylmethyldiethoxysilane; disulfide compounds such as dibutyl disulfide and γ-trimethoxysilylpropyl disulfide; and aromatic hydrocarbon compounds such as benzene and toluene. Among these, n-dodecyl mercaptan and mercaptosilane compounds are preferred because they have low odor, and mercaptosilane compounds are more preferred because they exhibit the effect of acting as a chain transfer agent and can simultaneously introduce crosslinkable silicon groups into the molecule. The chain transfer agent is preferably used in an amount of 0.1 to 35 mass%, more preferably 1 to 25 mass%, and particularly preferably 5 to 15 mass%, based on the total mass of all monomer components constituting the curable resin (B).

[0029] Furthermore, when synthesizing the curable resin (B) by copolymerization, a conventionally known initiator suitable for radical polymerization, anionic polymerization, or cationic polymerization may be used. For example, in the case of the commonly used radical polymerization, the polymerization initiator is a radical initiator. Examples of radical initiators that can be used include 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2-methyl-4-trimethoxysilylpentonitrile), 2,2'-azobis(2-methyl-4-methyldimethoxysilylpentonitrile), azo compounds such as VA-046B, VA-057, VA-061, VA-085, VA-086, VA-096, V-601, V-65, and VAm-110 manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., and peroxides such as benzoyl peroxide, t-alkyl peroxy esters, acetyl peroxide, and diisopropyl peroxycarbonate. The initiator is preferably used in an amount of 0.1 to 10 mass %, particularly preferably 0.5 to 5 mass %, based on the total mass of all monomer components constituting the curable resin (B).

[0030] The blending ratio (parts by mass) of the curable resin (A) and the curable resin (B) is preferably in the range of (A):(B) = 5:95 to 95:5, more preferably 20:80 to 90:10, particularly preferably 30:70 to 80:20, and most preferably 40:60 to 70:30. If the blending ratio (parts by mass) of the curable resin (B) is less than (A):(B) = 95:5, the effect of blending the curable resin (B) (the effect of improving various properties such as adhesion, heat resistance, oil resistance, and water resistance) may be diminished, whereas if the blending ratio (parts by mass) exceeds (A):(B) = 5:95, the viscosity may become extremely high, resulting in reduced workability.

[0031] [Regarding the boron trifluoride complex, component (C)] The boron trifluoride complex, which is component (C) used in the moisture-curable adhesive composition of the present invention, is a complex compound of boron trifluoride and a Lewis base, and is a catalyst compound for curing the curable resin (A) and the curable resin (B) by causing a condensation reaction of the crosslinkable silicon groups contained in the curable resin (A) and the curable resin (B).

[0032] Specific examples of the boron trifluoride complex serving as component (C) include boron trifluoride amine complexes, alcohol complexes, ether complexes, thiol complexes, sulfide complexes, carboxylic acid complexes, water complexes, etc. Among the boron trifluoride complexes, alcohol complexes and amine complexes are preferred because of their ease of availability and ease of blending, and amine complexes, which combine stability and catalytic activity, are most preferred.

[0033] Amine compounds used in the amine complexes of boron trifluoride include ammonia, monoethylamine, triethylamine, piperidine, aniline, morpholine, cyclohexylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, guanidine, 2,2,6,6-tetramethylpiperidine, 1,2,2,6,6-pentamethylpiperidine, N-methyl-3,3'-iminobis(propylamine), ethylenediamine, and diethylene Triamine, triethylenediamine, pentaethylenediamine, 1,2-diaminopropane, 1,3-diaminopropane, 1,2-diaminobutane, 1,4-diaminobutane, 1,9-diaminononane, ATU (3,9-bis(3-aminopropyl)-2,4,8,10-tetraoxaspiro[5.5]undecane), CTU guanamine (3,9-bis[2-(3,5-diamino-2,4,6-triazaphenyl)ethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane), dodecanoic acid dihydrazide, hexamethylenediamine, m-xylylenediamine, dianisidine, 4,4'-diamino-3,3'-diethyldiphenylmethane, diaminodiphenyl ether, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, tolidine base, m-toluylenediamine, o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, melamine, 1,3-diphenylguanidine, Compounds having multiple primary amino groups such as di-o-tolylguanidine, 1,1,3,3-tetramethylguanidine, bis(aminopropyl)piperazine, N-(3-aminopropyl)-1,3-propanediamine, bis(3-aminopropyl)ether, and Jeffamine (manufactured by Huntsman), piperazine, cis-2,6-dimethylpiperazine, cis-2,5-dimethylpiperazine, 2-methylpiperazine, N,N'-di-t-butylethylenediamine, Compounds having multiple secondary amino groups, such as amine, 2-aminomethylpiperidine, 4-aminomethylpiperidine, 1,3-di-(4-piperidyl)-propane, 4-aminopropylaniline, homopiperazine, N,N'-diphenylthiourea, N,N'-diethylthiourea, and N-methyl-1,3-propanediamine, as well as compounds having multiple secondary amino groups, such as methylaminopropylamine, ethylaminopropylamine, ethylaminoethylamine, laurylaminopropylamine, 2-hydroxyethylaminopropylamine, 1-(2-aminoethyl)piperazine, N-aminopropylpiperazine, 3-aminopyrrolidine, 1-o-tolylbiguanide, 2-aminomethylpiperazine, N-aminopropylaniline, ethylamine, 2-hydroxyethylaminopropylamine, laurylaminopropylamine, 2-aminomethylpiperidine, 4-aminomethylpiperidine, and compounds of the formula HN(CHNH). nCompounds represented by H(n≒5) (trade name: Polyate, Tosoh Corporation, Japan), N-alkylmorpholine, 1,8-diazabicyclo[5.4.0]undecene-7, 6-dibutylamino-1,8-diazabicyclo[5.4.0]undecene-7, 1,5-diazabicyclo[4.3.0]nonene-5, 1,4-diazabicyclo[2.2.2]octane, pyridine, N-alkylpiperidine, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene, and other bicyclic tertiary amine compounds, as well as γ-aminopropyltriethoxysilane and γ-aminopropylmethylsilane. Examples of aminosilane compounds include, but are not limited to, diethoxysilane, 4-amino-3-dimethylbutyltriethoxysilane, N-β(aminoethyl)-γ-aminopropyltriethoxysilane, N-β(aminoethyl)-γ-aminopropylmethyldiethoxysilane, N-3-[amino(dipropyleneoxy)]aminopropyltriethoxysilane, (aminoethylaminomethyl)phenethyltriethoxysilane, N-(6-aminohexyl)aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltriethoxysilane, and N-(2-aminoethyl)-11-aminoundecyltriethoxysilane. Amine complexes of boron trifluoride are commercially available and can be used in the present invention. Examples of commercially available products include Anchor 1040, Anchor 1115, Anchor 1170, Anchor 1222, and BAK1171 manufactured by Air Products Japan Co., Ltd.

[0034] The boron trifluoride complex of component (C) may be appropriately selected to obtain the desired curing rate, etc., and may be used alone or in combination of two or more. The amount of boron trifluoride complex of component (C) is preferably 0.01 to 10 parts by mass, more preferably 0.05 to 5.0 parts by mass, and most preferably 0.1 to 2.0 parts by mass, per 100 parts by mass of the total of the curable resin of component (A) and the curable resin of component (B). If the amount of boron trifluoride complex of component (C) is less than 0.01 part by mass, the curing acceleration effect may be insufficient, while if it exceeds 10 parts by mass, problems such as poor storage stability of the moisture-curable adhesive composition may occur.

[0035] [About the fluorescent whitening agent (D)] The "fluorescent brightening agent" as component (D) used in the moisture-curable adhesive composition according to the present invention is a component that, when used together with components (A) to (C), makes the moisture-curable adhesive composition according to the present invention colorless and transparent.

[0036] Examples of the fluorescent brightening agent, component (D), include coumarin derivatives, benzoxazole derivatives, naphthalene derivatives, pyrarizone derivatives, benzidine derivatives, and stilbene derivatives, and these can be selected appropriately and used alone or in combination of two or more.

[0037] Specific examples of the fluorescent brightener include Tinopal OB (BASF, Germany) as a benzoxazole / thiophene derivative, Kayalight (registered trademark) B (Nippon Kayaku Co., Ltd., Japan) as a coumarin derivative, Kayalight OSN (Nippon Kayaku Co., Ltd., Japan) and Kayalight OS (Nippon Kayaku Co., Ltd., Japan) as benzoxazole derivatives, Kayalight KB (Nippon Kayaku Co., Ltd., Japan) and NIKKAFLUOR KB (Nippon Chemical Industry Co., Ltd., Japan) as benzoxazole / naphthalene derivatives, and NIKKAFLUOR 2R conc. (Nippon Chemical Industry Co., Ltd., Japan), Whitefluor (registered trademark) PSN conc. (Sumitomo Chemical Co., Ltd., Japan), and NIKKAFLUOR RP conc. (Nippon Chemical Industry Co., Ltd., Japan) as benzoxazole / stilbene derivatives.

[0038] The amount of the fluorescent brightening agent (D) is not particularly limited, but is preferably 0.0002 to 1 part by mass, and more preferably 0.002 to 0.2 parts by mass, per 100 parts by mass of the total of the curable resin (A) and the curable resin (B), so that the moisture-curable adhesive composition according to the present invention is colorless and transparent. If the amount of the fluorescent brightening agent (D) is less than 0.0002 part by mass, the effect of eliminating the yellowness may be insufficient, while if it exceeds 1 part by mass, problems such as the adhesive composition becoming discolored may occur.

[0039] [Other ingredients] The moisture-curable adhesive composition of the present invention may contain any conventionally known compound or substance as other components, provided that the effects of the present invention are not impaired. For example, various resins other than the curable resin (A) used in the present invention (e.g., epoxy resins, acrylic resins, etc.), curing catalysts other than the boron trifluoride complex (C), adhesion-imparting components (e.g., silane coupling agents such as aminosilane compounds, epoxysilane compounds, mercaptosilane compounds, (meth)acrylicsilane compounds, isocyanatesilane compounds, and vinylsilane compounds, tackifying resins such as styrene resins, chlorinated polyolefin resins, etc.), hydrophilic or hydrophobic silica-based powders, acrylic resin powders, fillers such as calcium carbonate, thixotropic agents such as amide wax, dehydrating agents such as calcium oxide, diluents, plasticizers, flame retardants, oligomers, antioxidants, pigments, drying oils, etc. may be blended.

[0040] Specifically, a diluent can be blended into the moisture-curable adhesive composition according to the present invention, as long as the effect of the present invention is not impaired. The diluent may be a commercially available product, such as dipropylene glycol dimethyl ether (e.g., Proglide (registered trademark) DMM (BASF, Germany)).

[0041] The moisture-curable adhesive composition according to the present invention may contain an aminosilane within a range that does not impair the effects of the present invention. Commercially available aminosilanes may be used, such as KBM-903 (Shin-Etsu Chemical Co., Ltd., Japan).

[0042] The moisture-curable adhesive composition of the present invention may contain an antioxidant within a range that does not impair the effects of the present invention. Commercially available antioxidants may be used, such as Irganox (registered trademark) 1010 (BASF, Germany) and Tinuvin (registered trademark) 770DF (BASF, Germany).

[0043] The moisture-curable adhesive composition according to the present invention can be blended with a component capable of imparting color to the moisture-curable adhesive composition, as long as the effect of the present invention is not impaired. For example, heavy calcium carbonate NS#400 (Nitto Funka Kogyo Co., Ltd., Japan) or heavy calcium carbonate Nanox#30 (Maruo Calcium Co., Ltd., Japan) can be blended to impart a white hue to the moisture-curable adhesive composition, and toner NV7-224 (Nippon Pigment Co., Ltd.) can be blended to impart a black hue to the moisture-curable adhesive composition.

[0044] The moisture-curable adhesive composition of the present invention may contain a thixotropic agent, such as Disparlon (registered trademark) 6650 (Kusumoto Chemicals Co., Ltd., Japan), within the range that does not impair the effects of the present invention. [Example]

[0045] The present invention will be described in detail below based on examples, but the present invention is not limited to these examples.

[0046] 1. Reagents and substrates

[0047] The following reagents were used for the various tests: Tinopal OB (BASF, Germany), Kayalight B (Nippon Kayaku Co., Ltd., Japan), Kayalight OSN (Nippon Kayaku Co., Ltd., Japan), Kayalight OS (Nippon Kayaku Co., Ltd., Japan), Kayalight KB (Nippon Kayaku Co., Ltd., Japan), NIKKAFLUOR KB (Nippon Chemical Industry Co., Ltd., Japan), NIKKAFLUOR 2R conc. (Nippon Chemical Industry Co., Ltd., Japan), Whitefluor PSN conc. (Sumitomo Chemical Co., Ltd., Japan), NIKKAFLUOR RP conc. (Nippon Chemical Industry Co., Ltd., Japan), Oil Blue 2N (Orient Chemical Co., Ltd., Japan), Proglide DMM (BASF, Germany), KBM-903 (Shin-Etsu Chemical Co., Ltd., Japan), Irganox 1010 (BASF, Germany), Tinuvin 770DF (BASF, Germany), boron trifluoride monoethylamine (Stella Chemifa Co., Ltd., Japan), and heavy calcium carbonate. NS#400 (Nitto Funka Kogyo Co., Ltd., Japan), heavy calcium carbonate Nanox#30 (Maruo Calcium Co., Ltd., Japan), toner NV7-224 (Nippon Pigment Co., Ltd., Japan), and Disparlon 6650 (Kusumoto Chemicals Co., Ltd., Japan) were used.

[0048] 2. Preparation of adhesive composition

[0049] The curable resin of component (A) (i.e., the main chain is polyoxyalkylene and the terminal thereof is a group represented by the general formula (1); -SiR 1 a (OR 2 ) 3-n (However, R 1 represents an alkyl group having 1 to 10 carbon atoms, and R 2 represents an alkyl group having 1 to 6 carbon atoms, and a is 0, 1, or 2.) and a curable resin of component (B) (i.e., a curable resin having a hydrolyzable silyl group represented by the general formula (1); -SiR 1 a (OR 2 ) 3-n (However, R 1 represents an alkyl group having 1 to 10 carbon atoms, and R 2represents an alkyl group having 1 to 6 carbon atoms, and a is 0, 1 or 2. A liquid mixture of a curable resin having a hydrolyzable silyl group represented by the following formula (1) in the molecule was prepared.

[0050] [Preparation of component (A) curable resin] In a reaction vessel, 206.4 parts by mass of N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane was stirred at room temperature under a nitrogen atmosphere, while 172.2 parts by mass of methyl acrylate (2 molar equivalents relative to the N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane) was added dropwise over 1 hour, and the mixture was allowed to react at 50°C for 7 days to obtain a silane compound (SE-1) having a methyldimethoxysilyl group and a secondary amino group in the molecule.

[0051] In a separate reaction vessel, 100 parts by mass of PMLS4012 (manufactured by Asahi Glass Co., Ltd., product name: polyoxypropylene polyol, number average molecular weight 10,000), 4.83 parts by mass of isophorone diisocyanate, and a trace amount of Nikka Octix Zirconium (manufactured by Nippon Chemical Industry Co., Ltd., product name: 2-ethylhexanoic acid zirconyl compound solution (Zr content = approximately 12% by mass), 20 ppm in terms of zirconium metal relative to PMLS4012) were charged, and the mixture was reacted at 80°C for 3 hours while stirring and mixing under a nitrogen atmosphere, thereby obtaining a urethane-based resin (U-1) whose main chain is an oxyalkylene polymer and whose molecule has an isocyanate group.

[0052] 8.39 parts by mass of the silane compound (SE-1) was added to the urethane resin (U-1), and while stirring and mixing under a nitrogen atmosphere, the isocyanate groups in the urethane resin (U-1) and the secondary amino groups in the silane compound (SE-1) were reacted at 80°C for 1 hour to obtain a curable resin (A) whose main chain is an oxyalkylene polymer and whose molecule contains a urethane group, a urea group substituted with one active hydrogen, and a methyldimethoxysilyl group. After the reaction was completed, IR measurement revealed a characteristic absorption (2265 cm) attributed to the isocyanate group. -1 ) was not observed.

[0053] [Preparation of a liquid mixture of component (A) curable resin and component (B) curable resin] A reaction vessel was charged with 100 parts by weight of the curable resin (A) and heated to 80°C under a nitrogen atmosphere. A monomer mixture containing 37.5 parts by weight of methyl methacrylate, 25 parts by weight of lauryl methacrylate, 3.0 parts by weight of 3-acryloxypropyltrimethoxysilane, 7.0 parts by weight of 3-mercaptopropyltrimethoxysilane, and 0.50 parts by weight of 2,2'-azobis(2,4-dimethylvaleronitrile) was added dropwise over 30 minutes to carry out a polymerization reaction. After further reaction at 80°C for 30 minutes, a mixture of 0.200 parts by weight of 2,2'-azobis(2,4-dimethylvaleronitrile) and 10 parts by weight of methyl ethyl ketone was added dropwise to carry out a polymerization reaction. Next, after reacting for 30 minutes at 80°C, a mixed solution of 0.10 parts by mass of 2,2'-azobis(2,4-dimethylvaleronitrile) and 10 parts by mass of methyl ethyl ketone was added dropwise to carry out a polymerization reaction. After reacting for another 3 hours at 80°C, the methyl ethyl ketone was distilled off under reduced pressure to obtain a liquid mixture of the curable resin (A) and the curable resin (B) having a trimethoxysilyl group in the molecule. The mass ratio of this liquid mixture was 58:42 (curable resin (A):curable resin (B)).

[0054] Furthermore, the moisture-curable adhesive composition of the present invention and a comparative moisture-curable adhesive composition are each prepared according to the procedure described below.

[0055] The blending ratios of the raw materials in the moisture-curable adhesive compositions of the examples and comparative examples are summarized in Tables 1-1 to 1-6.

[0056] [Table 1-1] [Table 1-2] [Table 1-3] [Table 1-4] [Table 1-5] [Table 1-6]

[0057] <Procedure for preparing transparent moisture-curable adhesive composition> The curable resin and fluorescent agent were placed in a sealed reaction vessel (planetary mixer) equipped with a stirrer in the proportions (parts by weight) shown in Tables 1-1 to 1-4 and kneaded for 10 minutes at room temperature and normal pressure. The mixture was then stirred and mixed for 1 hour under reduced pressure of 60 mmHg or less while heating at 100-120°C. The mixture was then cooled and stirred for another hour. After depressurizing with nitrogen, the resulting paste-like slurry was added with a solution of the diluent Proglide DMM, the silane coupling agent KBM-903, the boron trifluoride complex boron trifluoride monoethylamine, and an antioxidant. The mixture was then kneaded under sealed conditions, shielded from moisture, to obtain a moisture-curable adhesive composition. The resulting moisture-curable adhesive composition was then filled into a sealed container shielded from moisture.

[0058] <Preparation procedure for white moisture-curable adhesive composition> The curable resin, fluorescent agent, and fillers (heavy calcium carbonate NS#400 and Nanox#30) were mixed in the proportions (parts by weight) shown in Table 1-5 into a sealed reaction vessel (planetary mixer) equipped with a stirrer. The mixture was mixed at room temperature and pressure for 10 minutes, then kneaded for 30 minutes under a reduced pressure of 60 mmHg or less. The mixture was then heated to 100-120°C and stirred for 1 hour under a reduced pressure of 60 mmHg or less. The mixture was then cooled and stirred for another hour. After depressurizing with nitrogen, the resulting paste-like slurry was added with a solution of the diluent Proglide DMM, the silane coupling agent KBM-903, the boron trifluoride complex boron trifluoride monoethylamine, and the thixotropic agent. The mixture was then kneaded under sealed conditions, protected from moisture, to obtain a moisture-curable adhesive composition. The resulting moisture-curable adhesive composition was then filled into a sealed container, protected from moisture.

[0059] <Procedure for preparing black moisture-curable adhesive composition> The curable resin, fluorescent agent, filler heavy calcium carbonate NS#400, Nanox#30, and toner NV7-224 were mixed in the proportions (parts by weight) shown in Table 1-6 into a sealed reaction vessel (planetary mixer) equipped with a stirrer. The mixture was mixed at room temperature and pressure for 10 minutes, then kneaded for 30 minutes under a reduced pressure of 60 mmHg or less. The mixture was then heated to 100-120°C and stirred for 1 hour under a reduced pressure of 60 mmHg or less. The mixture was then cooled and stirred for another hour. After depressurizing with nitrogen, the resulting paste-like slurry was added with a solution of the diluent Proglide DMM, the silane coupling agent KBM-903, the boron trifluoride complex boron trifluoride monoethylamine, and the thixotropic agent. The mixture was then kneaded under sealed conditions, protected from moisture, to obtain a moisture-curable adhesive composition. The resulting moisture-curable adhesive composition was then filled into a sealed container protected from moisture.

[0060] A moisture-curable adhesive composition for each example was prepared.

[0061] [Preparation of Moisture-Curable Adhesive Composition (Example 1-1)] 100 parts by weight of a liquid mixture of the curable resin (A) and the curable resin (B) and 0.02 parts by weight of the fluorescent brightener (D) Tinopal OB were placed in a sealed reaction vessel (planetary mixer) equipped with a stirrer and kneaded at room temperature and atmospheric pressure for 10 minutes. The mixture was then stirred and mixed for 1 hour under a reduced pressure of 60 mmHg or less while heated to 100-120°C. The mixture was cooled and stirred for another hour, and the pressure was released with nitrogen. To the resulting paste-like slurry, a solution containing 5 parts by weight of the diluent Proglide DMM, 5 parts by weight of the silane coupling agent aminosilane KBM-903, and 0.1 parts by weight of the boron trifluoride complex boron trifluoride monoethylamine (C) was added, and the mixture was kneaded under sealed conditions that excluded moisture, yielding the moisture-curable adhesive composition of Example 1-1. The resulting moisture-curable adhesive composition was filled in a sealed container that was moisture-proof, and stored until it was used in each test.

[0062] [Preparation of Moisture-Curable Adhesive Composition (Example 1-2)] The moisture-curable adhesive composition of Example 1-2 was obtained in the same manner as in Example 1-1, except that the amount of Tinopal OB, the fluorescent brightening agent of component (D), was changed to 0.5 parts by mass. The composition was then filled into an airtight container that was protected from moisture and stored until it was used in each test.

[0063] [Preparation of Moisture-Curable Adhesive Composition (Example 2-1)] The moisture-curable adhesive composition of Example 2-1 was obtained in the same manner as in Example 1-1, except that the amount of Kayalight B, the fluorescent brightening agent of component (D), was changed to 0.02 parts by mass. The composition was then filled into an airtight container that was moisture-proof and stored until use in each test.

[0064] [Preparation of Moisture-Curable Adhesive Composition (Example 3-1)] The moisture-curable adhesive composition of Example 3-1 was obtained in the same manner as in Example 1-1, except that the amount of Kayalight OSN, the fluorescent brightening agent of component (D), was changed to 0.02 parts by mass. The composition was then filled into an airtight container that was moisture-proof and stored until use in each test.

[0065] [Preparation of Moisture-Curable Adhesive Composition (Example 4-1)] The moisture-curable adhesive composition of Example 4-1 was obtained in the same manner as in Example 1-1, except that the amount of Kayalight OS, the fluorescent brightening agent of component (D), was changed to 0.02 parts by mass. The composition was then filled into an airtight container that was moisture-proof and stored until use in each test.

[0066] [Preparation of Moisture-Curable Adhesive Composition (Example 5-1)] The moisture-curable adhesive composition of Example 5-1 was obtained in the same manner as in Example 1-1, except that the amount of NIKKAFLUOR KB, the fluorescent brightening agent of component (D), was changed to 0.02 parts by mass. The composition was then filled into an airtight container that was protected from moisture and stored until use in each test.

[0067] [Preparation of Moisture-Curable Adhesive Composition (Example 6-1)] The moisture-curable adhesive composition of Example 6-1 was obtained in the same manner as in Example 1-1, except that the amount of NIKKAFLUOR RP conc., the fluorescent brightening agent of component (D), was changed to 0.02 parts by mass. The composition was then filled into an airtight container that was protected from moisture and stored until use in each test.

[0068] [Preparation of Moisture-Curable Adhesive Composition (Example 7-1)] The moisture-curable adhesive composition of Example 7-1 was obtained in the same manner as in Example 1-1, except that the amount of Tinopal OB, the fluorescent brightening agent of component (D), was changed to 0.002 parts by mass. The composition was then filled into an airtight container that was protected from moisture and stored until it was used in each test.

[0069] [Preparation of moisture-curable adhesive composition (Example 7-2)] The moisture-curable adhesive composition of Example 7-2 was obtained in the same manner as in Example 1-1, except that the amount of Tinopal OB, the fluorescent brightening agent (D), was changed to 0.005 parts by mass. The composition was then filled into an airtight container that was moisture-proof and stored until it was used in each test.

[0070] [Preparation of moisture-curable adhesive composition (Example 7-3)] The moisture-curable adhesive composition of Example 7-3 was obtained in the same manner as in Example 1-1, except that the amount of Tinopal OB, the fluorescent brightening agent of component (D), was changed to 0.008 parts by mass. The composition was then filled into an airtight container that was protected from moisture and stored until it was used in each test.

[0071] [Preparation of moisture-curable adhesive composition (Example 7-4)] The moisture-curable adhesive composition of Example 7-4 was obtained in the same manner as in Example 1-1, except that the amount of Tinopal OB, the fluorescent whitening agent of component (D), was changed to 0.01 parts by mass. The composition was then filled into an airtight container that was protected from moisture and stored until it was used in each test.

[0072] [Preparation of moisture-curable adhesive composition (Example 7-5)] The moisture-curable adhesive composition of Example 7-5 was obtained in the same manner as in Example 1-1, except that the amount of Tinopal OB, the fluorescent whitening agent of component (D), was changed to 0.02 parts by mass. The composition was then filled into an airtight container that was protected from moisture and stored until it was used in each test.

[0073] [Preparation of Moisture-Curable Adhesive Composition (Examples 7-6)] The moisture-curable adhesive composition of Example 7-6 was obtained in the same manner as in Example 1-1, except that the fluorescent brightening agent (D), Tinopal OB, was used in an amount of 1 part by mass. The composition was then filled into an airtight container that was moisture-proof and stored until use in each test.

[0074] [Preparation of moisture-curable adhesive composition (Example 8-1)] The moisture-curable adhesive composition of Example 8-1 was obtained in the same manner as in Example 1-1, except that the fluorescent brightening agent (D) was 0.002 parts by mass of Kayalight B. The composition was then filled into an airtight container that was protected from moisture and stored until use in each test.

[0075] [Preparation of moisture-curable adhesive composition (Example 8-2)] The moisture-curable adhesive composition of Example 8-2 was obtained in the same manner as in Example 1-1, except that the fluorescent brightening agent (D) was 0.005 parts by mass of Kayalight B. The composition was then filled into an airtight container that was protected from moisture and stored until use in each test.

[0076] [Preparation of moisture-curable adhesive composition (Example 8-3)] The moisture-curable adhesive composition of Example 8-3 was obtained in the same manner as in Example 1-1, except that the fluorescent brightening agent (D) was 0.01 parts by mass of Kayalight B. The composition was then filled into an airtight container that was protected from moisture and stored until use in each test.

[0077] [Preparation of moisture-curable adhesive composition (Example 9-1)] The moisture-curable adhesive composition of Example 9-1 was obtained by mixing them in the same manner as in Example 1-1, except that the fluorescent brightening agent (D) was 0.002 parts by mass of Kayalight OSN. The composition was then filled into an airtight container that blocks moisture and stored until use in each test.

[0078] [Preparation of moisture-curable adhesive composition (Example 9-2)] The moisture-curable adhesive composition of Example 9-2 was obtained in the same manner as in Example 1-1, except that the fluorescent brightening agent (D) was 0.01 parts by mass of Kayalight OSN. The composition was then filled into an airtight container that was moisture-proof and stored until use in each test.

[0079] [Preparation of Moisture-Curable Adhesive Composition (Example 10-1)] The moisture-curable adhesive composition of Example 10-1 was obtained in the same manner as in Example 1-1, except that the fluorescent brightening agent (D) was 0.002 parts by mass of Kayalight OS. The composition was then filled into an airtight container that was protected from moisture and stored until use in each test.

[0080] [Preparation of moisture-curable adhesive composition (Example 10-2)] The moisture-curable adhesive composition of Example 10-2 was obtained in the same manner as in Example 1-1, except that the fluorescent brightening agent (D) was 0.01 parts by mass of Kayalight OS. The composition was then filled into an airtight container that was protected from moisture and stored until use in each test.

[0081] [Preparation of moisture-curable adhesive composition (Example 11-1)] The moisture-curable adhesive composition of Example 11-1 was obtained in the same manner as in Example 1-1, except that the fluorescent brightening agent (D) was 0.002 parts by mass of NIKKAFLUOR KB. The composition was then filled into an airtight container that was protected from moisture and stored until use in each test.

[0082] [Preparation of moisture-curable adhesive composition (Example 11-2)] The moisture-curable adhesive composition of Example 11-2 was obtained in the same manner as in Example 1-1, except that the fluorescent brightening agent (D) was 0.01 parts by mass of NIKKAFLUOR KB. The composition was then filled into an airtight container that was protected from moisture and stored until use in each test.

[0083] [Preparation of moisture-curable adhesive composition (Example 12-1)] The moisture-curable adhesive composition of Example 12-1 was obtained in the same manner as in Example 1-1, except that the fluorescent brightening agent (D) was 0.002 parts by mass of NIKKAFLUOR 2R conc. The composition was filled into an airtight container that was protected from moisture and stored until use in each test.

[0084] [Preparation of moisture-curable adhesive composition (Example 12-2)] The moisture-curable adhesive composition of Example 12-2 was obtained in the same manner as in Example 1-1, except that the fluorescent brightening agent of component D) was 0.01 parts by mass of NIKKAFLUOR 2R conc. The composition was filled into an airtight container that was protected from moisture and stored until use in each test.

[0085] [Preparation of moisture-curable adhesive composition (Example 13-1)] The moisture-curable adhesive composition of Example 13-1 was obtained in the same manner as in Example 1-1, except that the fluorescent brightening agent (D) was 0.002 parts by mass of Whitefluor PSN conc. The composition was filled into an airtight container that was protected from moisture and stored until use in each test.

[0086] [Preparation of moisture-curable adhesive composition (Example 13-2)] The moisture-curable adhesive composition of Example 13-2 was obtained in the same manner as in Example 1-1, except that the fluorescent brightening agent (D) was 0.01 parts by mass of Whitefluor PSN conc. The composition was filled into an airtight container that was protected from moisture and stored until use in each test.

[0087] [Preparation of moisture-curable adhesive composition (Example 14-1)] The moisture-curable adhesive composition of Example 14-1 was obtained in the same manner as in Example 1-1, except that the fluorescent brightening agent (D) was 0.002 parts by mass of NIKKAFLUOR RP conc. The composition was filled into an airtight container that was protected from moisture and stored until use in each test.

[0088] [Preparation of moisture-curable adhesive composition (Example 14-2)] The moisture-curable adhesive composition of Example 14-2 was obtained in the same manner as in Example 1-1, except that the fluorescent brightening agent (D) was 0.01 parts by mass of NIKKAFLUOR RP conc. The composition was filled into an airtight container that was protected from moisture and stored until use in each test.

[0089] A comparative moisture-curable adhesive composition was prepared.

[0090] [Preparation of Moisture-Curable Adhesive Composition (Comparative Example 1-1)] A moisture-curable adhesive composition of Comparative Example 1-1 was obtained in the same manner as in Example 1-1, except that Tinopal OB, the fluorescent brightening agent of component (D), was not added. The composition was then filled into an airtight container that was moisture-proof and stored until it was used in each test.

[0091] [Preparation of Moisture-Curable Adhesive Composition (Comparative Example 1-2)] The moisture-curable adhesive composition of Comparative Example 1-2 was obtained in the same manner as in Example 7-1, except that Tinopal OB, the fluorescent brightening agent of component (D), was not added. The composition was then filled into an airtight container that was moisture-proof and stored until use in each test.

[0092] Furthermore, a white moisture-curable adhesive composition was prepared.

[0093] [Preparation of moisture-curable adhesive composition (Example 15-1)] 100 parts by mass of a liquid mixture of the curable resin (A) and the curable resin (B), 0.02 parts by mass of the fluorescent brightener (D) Tinopal OB, 16 parts by mass of the fillers heavy calcium carbonate NS#400 and Nanox #30 were placed in a sealed reaction vessel (planetary mixer) equipped with a stirrer and mixed for 10 minutes at room temperature and atmospheric pressure, then kneaded for 30 minutes under a reduced pressure of 60 mmHg or less. The mixture was then stirred and mixed for 1 hour while heating at 100-120°C under a reduced pressure of 60 mmHg or less. The mixture was further stirred and mixed for 1 hour while cooling, and after decompression with nitrogen, a solution containing 5 parts by mass of the diluent Proglide DMM, 5 parts by mass of the silane coupling agent KBM-903, and 0.1 parts by mass of boron trifluoride monoethylamine, a boron trifluoride complex (component (C)), was added to the resulting paste-like slurry, and the mixture was kneaded under sealed conditions that blocked out moisture to obtain a moisture-curing adhesive composition, which was then filled into a sealed container that blocked out moisture.

[0094] [Preparation of moisture-curable adhesive composition (Example 15-2)] The moisture-curable adhesive composition of Example 15-2 was obtained in the same manner as in Example 15-1, except that the amount of Tinopal OB, the fluorescent brightening agent (D), was changed to 1.5 parts by mass. The composition was then filled into an airtight container that was moisture-proof and stored until use in each test.

[0095] [Preparation of moisture-curable adhesive composition (Example 15-3)] The moisture-curable adhesive composition of Example 15-3 was obtained in the same manner as in Example 15-1, except that the fluorescent brightening agent (D) was 0.02 parts by mass of Kayalight B. The composition was then filled into an airtight container that could block moisture and stored until use in each test.

[0096] [Preparation of moisture-curable adhesive composition (Example 15-4)] The moisture-curable adhesive composition of Example 15-4 was obtained in the same manner as in Example 15-1, except that the fluorescent brightening agent (D) was 0.02 parts by mass of Kayalight OSN. The composition was then filled into an airtight container that was moisture-proof and stored until use in each test.

[0097] [Preparation of moisture-curable adhesive composition (Example 15-5)] The moisture-curable adhesive composition of Example 15-5 was obtained in the same manner as in Example 15-1, except that the fluorescent brightening agent (D) was 0.02 parts by mass of Kayalight OS. The composition was then filled into an airtight container that could block moisture and stored until use in each test.

[0098] [Preparation of moisture-curable adhesive composition (Example 15-6)] The moisture-curable adhesive composition of Example 15-6 was obtained in the same manner as in Example 15-1, except that the fluorescent brightening agent (D) was 0.02 parts by mass of NIKKAFLUOR KB. The composition was then filled into an airtight container that was protected from moisture and stored until use in each test.

[0099] [Preparation of moisture-curable adhesive composition (Example 15-7)] The moisture-curable adhesive composition of Example 15-7 was obtained in the same manner as in Example 15-1, except that the fluorescent brightening agent (D) was 0.02 parts by mass of NIKKAFLUOR 2R conc. The composition was filled into an airtight container that was protected from moisture and stored until use in each test.

[0100] [Preparation of moisture-curable adhesive composition (Example 15-8)] The moisture-curable adhesive composition of Example 15-8 was obtained in the same manner as in Example 15-1, except that the fluorescent brightening agent (D) was 0.02 parts by mass of Whitefluor PSN conc. The composition was filled into an airtight container that was moisture-proof, and stored until use in each test.

[0101] [Preparation of moisture-curable adhesive composition (Example 15-9)] The moisture-curable adhesive composition of Example 15-9 was obtained in the same manner as in Example 15-1, except that the fluorescent brightening agent (D) was 0.02 parts by mass of NIKKAFLUOR RP conc. The composition was filled into an airtight container that was protected from moisture and stored until use in each test.

[0102] Furthermore, a black moisture-curable adhesive composition was prepared.

[0103] [Preparation of moisture-curable adhesive composition (Example 16-1)] The moisture-curable adhesive composition of Example 16-1 was obtained in the same manner as in Example 15-1, except that 3 parts by mass of toner NV7-224 was added. The composition was then filled into a sealed container that was protected from moisture and stored until it was used in each test.

[0104] [Preparation of moisture-curable adhesive composition (Example 16-2)] The moisture-curable adhesive composition of Example 16-2 was obtained in the same manner as in Example 15-2, except that 3 parts by mass of toner NV7-224 was added. The composition was then filled into a sealed container that was protected from moisture and stored until it was used in each test.

[0105] [Preparation of moisture-curable adhesive composition (Example 16-3)] The moisture-curable adhesive composition of Example 16-3 was obtained in the same manner as in Example 15-3, except that 3 parts by mass of toner NV7-224 was added. The composition was then filled into a sealed container that was protected from moisture and stored until it was used in each test.

[0106] [Preparation of moisture-curable adhesive composition (Example 16-4)] The moisture-curable adhesive composition of Example 16-4 was obtained in the same manner as in Example 15-4, except that 3 parts by mass of toner NV7-224 was added. The composition was then filled into a sealed container that was protected from moisture and stored until it was used in each test.

[0107] [Preparation of moisture-curable adhesive composition (Example 16-5)] The moisture-curable adhesive composition of Example 16-5 was obtained in the same manner as in Example 15-5, except that 3 parts by mass of toner NV7-224 was added, and the composition was filled into an airtight container that was protected from moisture and stored until use in each test.

[0108] [Preparation of moisture-curable adhesive composition (Example 16-6)] The moisture-curable adhesive composition of Example 16-6 was obtained in the same manner as in Example 15-6, except that 3 parts by mass of toner NV7-224 was added, and the composition was filled into an airtight container that was protected from moisture and stored until use in each test.

[0109] [Preparation of moisture-curable adhesive composition (Example 16-7)] The moisture-curable adhesive composition of Example 16-7 was obtained in the same manner as in Example 15-7, except that 3 parts by mass of toner NV7-224 was added, and the composition was filled into an airtight container that was protected from moisture and stored until use in each test.

[0110] [Preparation of moisture-curable adhesive composition (Example 16-8)] The moisture-curable adhesive composition of Example 16-8 was obtained in the same manner as in Example 15-8, except that 3 parts by mass of toner NV7-224 was added, and the composition was filled into an airtight container that was protected from moisture and stored until use in each test.

[0111] [Preparation of moisture-curable adhesive composition (Example 16-9)] The moisture-curable adhesive composition of Example 16-9 was obtained in the same manner as in Example 15-9, except that 3 parts by mass of toner NV7-224 was added, and the composition was filled into an airtight container that was protected from moisture and stored until use in each test.

[0112] 3. Evaluation test of moisture-curing adhesive composition

[0113] [Procedure for evaluating color difference and turbidity of moisture-curable adhesive compositions]

[0114] Using the moisture-curable adhesive compositions of each Example and Comparative Example, tests are carried out to confirm and evaluate the color difference and turbidity of the cured film formed by curing each moisture-curable adhesive composition.

[0115] The moisture-curable adhesive composition of each Example and Comparative Example was poured into a circular container with a diameter of 50 mm and a thickness of 2 mm, and cured for 7 days in an atmosphere of 23±2°C and a relative humidity of 50±5% to form a cured film with a thickness of 2 mm. The YI value and haze (turbidity) value of the cured film were measured using a COH400 simultaneous color and turbidity analyzer (Nippon Denshoku Industries Co., Ltd., Japan), and the values ​​were recorded. Here, the color difference of the cured film is calculated from the measured X, Y, and Z values ​​of the cured film using the formula YI = 100(1.28X - 1.06Z) / Y. A value greater than +2 gives a yellowish appearance, a value below -2 gives a white to blue appearance, a value below ±2 gives a colorless appearance, and the smaller the value and the closer it is to 0, the more the film is perceived as virtually colorless. Furthermore, when the measured turbidity (%) of the cured film is 30 or less, it is judged to have sufficient transparency for practical use.

[0116] [Procedure for confirming viscosity of moisture-curable adhesive composition]

[0117] A viscosity confirmation test is carried out using the moisture-curable adhesive composition of each Example and Comparative Example.

[0118] Each moisture-curing adhesive composition was placed in a 50 cc plastic container and the viscosity was measured using a viscometer TVB-15H (Toki Sangyo Co., Ltd., Japan) at 10 rotations in an atmosphere of 23°C. The viscosity when using Tinopal OB was set to 1, and the viscosity under various conditions was expressed as a ratio, and each value was recorded.

[0119] [Procedure for determining the tensile shear adhesive strength of moisture-curable adhesive compositions]

[0120] Using the moisture-curable adhesive compositions of each Example and Comparative Example, a test was carried out to confirm the tensile shear adhesive strength.

[0121] Each moisture-curing adhesive composition was applied to an acrylic plate (length: 100 mm, width: 25 mm, thickness: 3 mm) whose surface had been degreased with ethanol. The plates were then bonded together with 0.2 mm diameter glass beads as spacers, with an overlap length of 12.5 mm ± 0.25 mm, to ensure a consistent adhesive thickness. The plates were then cured at 23 ± 2°C and 50 ± 5% relative humidity for 7 days to obtain test specimens. The tensile shear bond strength of each test specimen was then measured. Tensilon universal testing machine (A&D Co., Ltd., Japan) was used to measure the tensile shear bond strength in accordance with JIS K 6850 at a tensile speed of 5 mm / min, and the measured values ​​were recorded.

[0122] 4. Results

[0123] [Evaluation results of moisture-curing adhesive compositions based on turbidity and color difference] The moisture-curable adhesive compositions of each Example and Comparative Example were used to evaluate color difference and turbidity, and the results are shown in Tables 2-1 to 2-4.

[0124] [Table 2-1] [Table 2-2] [Table 2-3] [Table 2-4]

[0125] A test for checking the color difference using the moisture-curable adhesive compositions of each Example and Comparative Example was carried out using a color difference test for moisture-curable adhesive compositions, and the color difference was recorded.

[0126] As a result, the color difference for the moisture-curable adhesive composition of Comparative Example 1-1 was 1.98, which was within the range visually perceived as approaching yellow to colorless, but was not excellent in the desired degree of colorlessness where it was visually perceived as colorless with virtually no noticeable coloration.Furthermore, the color difference for the moisture-curable adhesive composition of Comparative Example 1-2, in which an antioxidant was added to Comparative Example 1-1, was 2.12, and it was confirmed that it was visually perceived as having a slight yellowish tinge (Table 2-1).

[0127] On the other hand, the color differences of the moisture-curable adhesive compositions of Examples 1-1 to 14-2 were -0.19, 0.12, 0.20, 0.58, 0.56, -0.33, 0.81, 0.68, 0.48, 0.32, 0.35, -0.12, -0.35, 0.54, 0.50, 0.45, 0.77, 0.54, 1.02, 0.55, 0.89, 0.75, 1.11, 0.78, 0.75, 0.68, 1.20, and 0.79, respectively, which were significantly smaller than those of the comparative examples. It was also found that even when an antioxidant, which was shown in the comparative examples to cause a yellowish tint when added, was added to the moisture-curable adhesive composition containing components (A) to (D), a moisture-curable adhesive composition was obtained that exhibited an excellent degree of colorlessness, so that the composition was visually recognized as being colorless with virtually no noticeable color (Tables 2-1 to 2-4).

[0128] Next, a test was conducted to check the turbidity of the moisture-curable adhesive composition of each Example and Comparative Example, using a turbidity test for the moisture-curable adhesive composition, and the turbidity was recorded.

[0129] As a result, the turbidity of the moisture-curable adhesive compositions of Comparative Example 1-1 and Comparative Example 1-2 was 2.01 and 4.11, respectively, confirming that the compositions had high transparency (Table 2-1 and Table 2-2).Furthermore, the turbidity of the moisture-curable adhesive compositions of Examples 1-1 to 6-1 was 1.65, 2.13, 1.84, 4.59, 2.16, 2.54, and 3.91, respectively, confirming that the compositions had high transparency (Table 2-1). Furthermore, the turbidity of the moisture-curable adhesive compositions of Examples 7-1 to 14-2 to which an antioxidant was added was 3.89, 4.05, 3.99, 4.02, 4.13, 5.12, 3.77, 4.01, 4.03, 3.55, 3.98, 4.01, 4.13, 3.55, 3.98, 4.01, 4.13, 3.87, 3.56, 5.12, 6.35, 3.68, 3.98, 5.23, and 6.89, respectively, confirming that regardless of the concentration or fluorescent brightener used, a product having the characteristic of high transparency was obtained (Tables 2-2 to 2-4).

[0130] It has been revealed that the moisture-curable adhesive composition of the present invention exhibits the excellent property of being colorless and transparent. Furthermore, it has been revealed that the range of types and amounts of fluorescent brighteners used in the moisture-curable adhesive composition of the present invention, which has colorless transparency, is extremely wide, making it highly versatile.

[0131] Furthermore, because it is colorless and transparent, it is understood that the color will not change even if the moisture-curable adhesive composition of the present invention is colored with a pigment, etc. When the colors of the moisture-curable adhesive compositions of Examples 15-1 to 16-9, in which color was added to the moisture-curable adhesive composition of the present invention, were checked, it was confirmed that the color was consistent with the original color design.

[0132] [Confirmation of viscosity change, adhesion, and curing properties of moisture-curable adhesive compositions] The viscosity of the moisture-curable adhesive compositions of the above-mentioned Examples and Comparative Examples was confirmed, and the results are shown in Tables 2-1 to 2-4.

[0133] When the initial viscosity of the moisture-curable adhesive compositions of each Example and Comparative Example at the time of production was confirmed, it was confirmed that the viscosity ratio under various conditions, when the viscosity when Tinopal OB was used, was set to 1, was 0.98 to 1.11, with almost no change (Tables 2-1 to 2-4). Furthermore, the storage stability of each of the moisture-curable adhesive compositions was confirmed when they were kept in an environment of 50°C for 2 weeks in an accelerated test, and it was confirmed that the viscosity ranged from 0.98 to 1.19, with almost no change in viscosity. It was also confirmed that each of the moisture-curable adhesive compositions had good adhesion and curability.

[0134] [Confirmation of tensile shear adhesive strength of moisture-curable adhesive composition] The tensile shear adhesive strength of the moisture-curable adhesive compositions of the above-mentioned Examples and Comparative Examples was confirmed, and the results are shown in Tables 2-1 to 2-4.

[0135] The tensile shear adhesive strength of each moisture-curable adhesive composition was confirmed to be 1.09 to 1.46 N mm 2 , and 1.17 to 1.32 N·mm for each comparative example. 2 It was confirmed that all of the values ​​were favorable (Tables 2-1 to 2-4).

[0136] [Confirmation of luminescence of moisture-curable adhesive composition]

[0137] Furthermore, it was confirmed whether the cured film of the colorless and transparent moisture-curable adhesive composition of the above example was capable of visually emitting light when irradiated with ultraviolet light in the A region.

[0138] Each of the moisture-curing adhesive compositions described above was poured into a circular container with a diameter of 50 mm and a thickness of 2 mm to create a cured film (2 mm thick). The cured film was then irradiated with UV-A light (4 W black light, fluorescent wavelength: 365 nm, Ohm Electric Co., Ltd., Japan) at a distance of 10 cm in a 23°C atmosphere, and the state of light emission was confirmed visually. As a result, it was confirmed that, in the cured film using the colorless and transparent moisture-curing adhesive composition of each example, which is the moisture-curing adhesive composition of the present invention, light emission was visible when irradiated with UV-A light, making it possible to identify the presence of the cured film by light emission. On the other hand, in the cured film using the moisture-curing adhesive composition of the comparative example, light emission from the cured film was not visible even when irradiated with UV-A light. [Industrial Applicability]

[0139] As in the present invention, the moisture-curable adhesive composition is prepared by using a curable resin (A) having a main chain of polyoxyalkylene and a terminal group of the general formula (1);-SiR 1 a (OR 2 ) 3-n (However, R 1 represents an alkyl group having 1 to 10 carbon atoms, and R 2 represents an alkyl group having 1 to 6 carbon atoms, and a is 0, 1, or 2. The curable resin having a hydrolyzable silyl group represented by the general formula (1);-SiR 1 a (OR 2 ) 3-n (However, R 1 represents an alkyl group having 1 to 10 carbon atoms, and R 2 represents an alkyl group having 1 to 6 carbon atoms, and a is 0, 1, or 2. By containing a curable resin having a hydrolyzable silyl group represented by the formula (I), a boron trifluoride complex as component (C), and a fluorescent brightening agent as component (D), it has become possible to provide a new moisture-curable adhesive composition that is extremely colorless and transparent, does not change color when colored, and has good viscosity and adhesive strength.

Claims

1. The composition contains: (A) a curable resin having a polyoxyalkylene main chain at its terminal with a hydrolyzable silyl group represented by the following general formula (1); (B) a curable resin having a vinyl copolymer main chain at its terminal with a hydrolyzable silyl group represented by the following general formula (1); (C) a boron trifluoride complex; and (D) a fluorescent brightening agent; A moisture-curable adhesive composition characterized in that component (A) has a urethane bond and / or a urea bond in the molecule. General formula (1); -SiR １ ａ (OR ２ ) ３－ａ (However, R １ represents an alkyl group having 1 to 10 carbon atoms, and R ２ represents an alkyl group having 1 to 6 carbon atoms, and a is 0, 1, or 2.

2. 2. The moisture-curable adhesive composition according to claim 1, wherein the color difference (YI value) of the cured product is −0.35 or more and 1.20 or less.

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