Sealant material for paint undercoat and method for producing sealant material for paint undercoat

Abstract

To provide a sealant material for paint undercoat that comprises a polyoxyalkylene polymer having a reactive silicon group and yields a cured product having superior adhesion to an applied paint, and also to provide a method for producing the sealant material for paint undercoat.SOLUTION: This sealant material for paint undercoat comprises a polyoxyalkylene polymer (A) having a reactive silicon group, the sealant material further comprising an epoxy compound (B) and an aminosilane coupling agent (C) having a triethoxysilyl group, wherein the epoxy compound (B) comprises, in its structure, an aromatic ring and / or a cycloalkane ring.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a paint-undercoat sealant material, which comprises a polyoxyalkylene polymer (A) having a reactive silicon group, an epoxy compound (B), and an aminosilane coupling agent (C) having a triethoxysilyl group, wherein the epoxy compound (B) has an aromatic ring and / or a cycloalkane ring in its structure, and a method for producing the paint-undercoat sealant material. [Background technology]

[0002] Organic polymers having at least one reactive silicon group in the molecule can be crosslinked even at room temperature by forming siloxane bonds accompanied by hydrolysis of the silyl groups due to moisture, etc. It is known that organic polymers having reactive silicon groups have the property of giving rubber-like cured products through such crosslinking reactions.

[0003] Among organic polymers having reactive silicon groups, polyoxyalkylene polymers having reactive silicon groups are widely used in applications such as sealants, sealing materials, adhesives, and waterproofing materials (Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-221501 Summary of the Invention [Problem to be solved by the invention]

[0005] In some cases, it is desirable to apply a paint to the surface of a sealant that has cured. Therefore, there is a demand for a paint-underlay sealant that can provide a cured product that has good adhesion to the paint.

[0006] The present invention has been made in view of the above-mentioned problems, and aims to provide a paint-underlay sealant material that contains a polyoxyalkylene polymer having a reactive silicon group and that gives a cured product that has good adhesion to an applied paint, and a method for producing the paint-underlay sealant material. [Means for solving the problem]

[0007] The present inventors have discovered that the above-mentioned problems can be solved by a sealant material for paint substrates containing a polyoxyalkylene polymer (A) having a reactive silicon group, an epoxy compound (B), and an aminosilane coupling agent (C) having a triethoxysilyl group, wherein the epoxy compound (B) has an aromatic ring and / or a cycloalkane ring in its structure, and have thus completed the present invention.

[0008] More specifically, the present invention provides the following (1) to (4). (1) A composition comprising a polyoxyalkylene polymer (A) having a reactive silicon group, an epoxy compound (B), and an aminosilane coupling agent (C) having a triethoxysilyl group, A sealant material for use under paint, in which the epoxy compound (B) has an aromatic ring and / or a cycloalkane ring in its structure. (2) The reactive silicon group is represented by the following formula (1): -SiR 1 (OCH3)2(1) (In formula (1), R 1 is a substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms, or R 0 3SiO-, and three R 0 are hydrocarbon groups having 1 to 20 carbon atoms, and they may be the same or different. The sealant material for paint undercoat according to (1) is represented by the following formula: (3) A paint-undercoat sealant according to (1) or (2), which contains a (meth)acrylic polymer (D) having a reactive silicon group. (4) mixing a polyoxyalkylene polymer (A) having a reactive silicon group, an epoxy compound (B), and an aminosilane coupling agent (C) having a triethoxysilyl group to obtain a mixture; mixing the mixture with a curing catalyst (E), A method for producing a sealant material for use under paint, wherein the epoxy compound (B) has an aromatic ring and / or a cycloalkane ring in its structure. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a paint-undercoat sealant material that contains a polyoxyalkylene polymer having a reactive silicon group and that gives a cured product that has good adhesion to an applied paint, and a method for producing the paint-undercoat sealant material. DETAILED DESCRIPTION OF THE INVENTION

[0010] The present invention will be described in detail below.

[0011] <Sealant for paint base> The paint-undercoat sealant material contains a polyoxyalkylene polymer (A) having a reactive silicon group, an epoxy compound (B), and an aminosilane coupling agent (C) having a triethoxysilyl group. The epoxy compound (B) has an aromatic ring and / or a cycloalkane ring in its structure. The paint-undercoat sealant material may contain various other additives as required.

[0012] The essential and optional components that the paint-under-surface sealant material may contain are described below.

[0013] <Polyoxyalkylene polymer (A)> The polyoxyalkylene polymer (A) (hereinafter sometimes simply referred to as "polymer (A)") has a reactive silicon group at the end of the molecular chain. The reactive silicon group is not particularly limited as long as it is capable of forming a siloxane bond. The reactive silicon group is represented by the following formula (1): -SiR 1 (OCH3)2(1) (In formula (1), R 1 is a substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms, or R 0 3SiO-, and three R 0 are hydrocarbon groups having 1 to 20 carbon atoms, and they may be the same or different. Preferably, it is represented by The following formula (2): -SiR 1 3-a X a (2) (In formula (2), R 1 is a substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms, or R 0 3SiO-, and three R 0 are hydrocarbon groups having 1 to 20 carbon atoms, which may be the same or different, X represents a hydroxyl group or a hydrolyzable group; a is 1, 2, or 3; R 1 , X, when there are multiple of them, they may be the same or different.) The reactive silicon group may be represented by the following formula: Polymer (A) has a polymer backbone and a polymer chain end bonded to the polymer backbone. In the specification and claims of this application, the polymer backbone is also referred to as a "main chain structure." The polymer backbone is a structure in which multiple structural units derived from monomers are bonded in succession. The monomer may be one type or multiple types.

[0014] The polymer chain end is a moiety located at the end of the polymer (A). The number of polymer chain ends of the polymer (A) is 2 when the main chain structure is linear, and 3 or more when the polymer backbone is branched. When the polymer (A) is a mixture of a polymer having a linear main chain structure and a polymer having a branched main chain structure, the number of polymer chain ends is an average value between 2 and 3.

[0015] The reactive silicon group may be present in the polymer backbone or at the polymer chain terminal. Two or more reactive silicon groups may be present at the polymer chain terminal. In the polymer (A), the reactive silicon group is preferably present at the polymer chain terminal.

[0016] (reactive silicon group) The reactive silicon group is a group that can generate a silanol group by hydrolysis. When the reactive silicon group generates a silanol group, the polymer (A) is crosslinked by a condensation reaction between the silanol groups. As mentioned above, the reactive silicon group is not particularly limited. The reactive silicon group is preferably a group represented by the following formula (1), and may be a group represented by the following formula (2). -SiR 1 (OCH3)2(1) -SiR 1 3-a X a (2)

[0017] In formula (1) and formula (2), R 1 is a substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms, or R 0 3SiO- represents a triorganosiloxy group. 0 are hydrocarbon groups having 1 to 20 carbon atoms, and they may be the same or different. In formula (2), X represents a hydroxyl group or a hydrolyzable group. a is 1, 2, or 3. R 1 , X, when there are a plurality of them, they may be the same or different.

[0018] R in formula (1) and formula (2)1 Specific examples of R include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, n-hexyl, 2-ethylhexyl, and n-dodecyl; unsaturated hydrocarbon groups such as vinyl, isopropenyl, and allyl; alkoxymethyl groups such as methoxymethyl; halogenated methyl groups such as chloromethyl; cycloalkyl groups such as cyclohexyl; aryl groups such as phenyl, toluyl, and 1-naphthyl; and aralkyl groups such as benzyl. Among these groups, alkyl and aryl groups are preferred, with methyl, ethyl, and phenyl groups being more preferred, methyl and ethyl groups being even more preferred, and methyl being particularly preferred. In formula (2), R 1 If there are multiple R 1 may be the same group or a combination of two or more different groups.

[0019] X in formula (2) is a hydroxyl group or a hydrolyzable group. The hydrolyzable group is not particularly limited and may be a known hydrolyzable group. Specific examples of the hydrolyzable group include a hydrogen atom, a halogen atom, an alkoxy group, an acyloxy group, a ketoximate group, an amino group, an amide group, an acid amide group, an aminooxy group, a mercapto group, and an alkenyloxy group. Among these, an alkoxy group, an acyloxy group, a ketoximate group, and an alkenyloxy group are preferred, and an alkoxy group such as a methoxy group and an ethoxy group is more preferred because of its mild hydrolysis and ease of handling. A methoxy group is preferred because it allows for easy adjustment of the curing property of the paint substrate sealant.

[0020] The reactive silicon group represented by formula (2) is not particularly limited. Specific examples of the reactive silicon group represented by formula (2) include dimethoxymethylsilyl, diethoxymethylsilyl, trimethoxysilyl, triethoxysilyl, dimethoxyphenylsilyl, methoxymethyldimethoxysilyl, methoxymethyldiethoxysilyl, triisopropenyloxysilyl, and triacetoxysilyl. Among these, dimethoxymethylsilyl and trimethoxysilyl are preferred because they facilitate the synthesis of polymer (A). Trimethoxysilyl and methoxymethyldimethoxysilyl are preferred because they have excellent curability. Dimethoxymethylsilyl is particularly preferred because it has excellent stability.

[0021] The reactive silicon group represented by formula (1) is not particularly limited. Specific examples of the reactive silicon group represented by formula (1) include a dimethoxymethylsilyl group and a dimethoxyethylsilyl group. The reactive silicon group represented by formula (1) is preferably a dimethoxymethylsilyl group.

[0022] (Main chain structure of polymer (A)) The polymer (A) is a polyoxyalkylene polymer. Therefore, the main chain structure of the polymer is made of a polyoxyalkylene polymer. Specific examples of the main chain structure of the polymer (A) include polyoxyalkylene polymers such as polyoxyethylene polymers, polyoxypropylene polymers, polyoxybutylene polymers, polyoxytetramethylene polymers, polyoxyethylene-polyoxypropylene copolymers, and polyoxypropylene-polyoxybutylene copolymers.

[0023] Among polyoxyalkylene polymers, polyoxypropylene is preferred as the main chain structure because it has excellent deep curing properties as a one-component composition due to its high moisture permeability and also has excellent adhesive properties.

[0024] The polyoxyalkylene polymer is -R 3 It is a polymer having a repeating unit represented by -O-.3 R is a linear or branched alkylene group having 1 to 14 carbon atoms. 3 As —R, a linear or branched alkylene group having 2 to 4 carbon atoms is more preferred. 3 Specific examples of the repeating unit represented by -O- include -CHO-, -CHCHO-, -CHCH(CH)O-, -CHCH(CH)O-, -CHC(CH)(CH)O-, and -CHCHCHCHO-. The main chain structure of the polyoxyalkylene polymer may consist of only one type of repeating unit, or may consist of two or more types of repeating units. In particular, when used as a paint-undercoat sealant, adhesive, or the like, a polyoxypropylene polymer having oxypropylene repeating units in an amount of 50% by weight or more, preferably 80% by weight or more, of the polymer main chain structure is preferred as the polyoxyalkylene polymer. This is because such polyoxyalkylene polymers are amorphous and have relatively low viscosity.

[0025] The main chain structure of the polyoxyalkylene polymer may be linear or branched.

[0026] The polyoxyalkylene polymer is preferably a polymer obtained by ring-opening polymerization of a cyclic ether compound in the presence of an initiator using a polymerization catalyst.

[0027] Examples of the cyclic ether compound include ethylene oxide, propylene oxide, butylene oxide, tetramethylene oxide, tetrahydrofuran, etc. These cyclic ether compounds may be used alone or in combination of two or more. Among these cyclic ether compounds, propylene oxide is particularly preferred because it can give an amorphous polyether polymer having a relatively low viscosity.

[0028] Specific examples of the initiator include alcohols such as butanol, ethylene glycol, propylene glycol, propylene glycol monoalkyl ether, butanediol, hexamethylene glycol, neopentyl glycol, diethylene glycol, dipropylene glycol, triethylene glycol, glycerin, trimethylolmethane, trimethylolpropane, pentaerythritol, and sorbitol; and polyoxyalkylene polymers such as polyoxypropylene diol, polyoxypropylene triol, polyoxyethylene diol, and polyoxyethylene triol.

[0029] The method for synthesizing the polyoxyalkylene polymer is not particularly limited. Examples of methods for synthesizing polyoxyalkylene polymers include a polymerization method using an alkali catalyst such as KOH; a polymerization method using a transition metal compound-porphyrin complex catalyst, such as the complex obtained by reacting an organoaluminum compound with porphyrin, as disclosed in JP-A-61-215623; a polymerization method using a composite metal cyanide complex catalyst, as disclosed in JP-B-46-27250, JP-B-59-15336, U.S. Pat. Nos. 3,278,457, 3,278,458, 3,278,459, 3,427,256, 3,427,334, and 3,427,335; a polymerization method using a catalyst made of a polyphosphazene salt, as exemplified in JP-A-10-273512; and a polymerization method using a catalyst made of a phosphazene compound, as exemplified in JP-A-11-060722. The polymerization method using a composite metal cyanide complex catalyst is more preferred because it has low production costs and can produce a polymer with a narrow molecular weight distribution.

[0030] The main chain structure of the polymer (A) may be a polyoxyalkylene polymer containing bonds other than ether bonds, such as urethane bonds and urea bonds, within the range that does not significantly impair the desired effects. Specific examples of polymers having such a main chain structure include polyurethane prepolymers and polyurea prepolymers.

[0031] The polyurethane prepolymer can be obtained by a known method such as a method of reacting a polyol compound with a polyisocyanate compound, and the polyurea prepolymer can be obtained by a known method such as a method of reacting a polyamine compound with a polyisocyanate compound. The main chain structure may be a prepolymer having a combination of urethane bonds and urea bonds, which is obtained by reacting a polyol compound and a polyamine compound with a polyisocyanate compound.

[0032] Specific examples of the polyol compound include polyether polyol, polyester polyol, polycarbonate polyol, and polyether polyester polyol.

[0033] Specific examples of polyisocyanate compounds include diphenylmethane diisocyanate, tolylene diisocyanate, xylylene diisocyanate, methylene-bis(cyclohexyl isocyanate), isophorone diisocyanate, and hexamethylene diisocyanate.

[0034] The polyurethane prepolymer may have a terminal group of either a hydroxyl group or an isocyanate group, and the polyurea prepolymer may have a terminal group of either an amino group or an isocyanate group.

[0035] In the case of a cured product of a sealant material for paint substrates that contains, as polymer (A), a polymer having one or more types of bonds selected from urethane bonds, urea bonds, and ester bonds in the main chain structure, the strength of the cured product may decrease due to cleavage of the urethane bonds, urea bonds, or ester bonds in the main chain structure due to heat or the like.

[0036] When a polymer containing an amide bond in the main chain structure is used as the polymer (A), the curing property of the sealant for paint substrate may be improved. 4 It is represented by -C(=O)-. 4is a hydrogen atom or an organic group which may have a substituent. When the amount of amide bonds in the main chain structure is within an appropriate range, the viscosity of the polymer is low, and a decrease in strength of the cured product due to cleavage of the amide bonds due to heat or the like and an increase in viscosity of the paint-under-surface sealant due to storage are unlikely to occur, resulting in good workability of the paint-under-surface sealant.

[0037] When the polymer (A) contains an amide bond in the main chain structure, the average number of amide bonds per molecule is preferably 1 to 10, more preferably 1.5 to 5, and even more preferably 2 to 3. When the average number of amide bonds per molecule is within this range, the curing property of the sealant for paint substrate is good, the viscosity of the polymer (A) is low, and the polymer (A) and the sealant for paint substrate are easy to handle.

[0038] As the polymer (A) described above, a polyoxyalkylene polymer that does not contain a urethane bond, a urea bond, an ester bond, or an amide bond in the main chain structure is most preferred, from the viewpoint of obtaining a sealant material for paint substrates that is excellent in storage stability and workability.

[0039] The polymer (A) is preferably a polymer obtained by introducing a reactive silicon group into a polymer by any of the following methods (a) to (d). (a) After converting the terminal hydroxyl groups of the hydroxyl-terminated organic polymer into carbon-carbon unsaturated groups, the carbon-carbon unsaturated groups are converted into HSiR 1 3-a X a A method of hydrosilylation using a hydrosilane represented by the formula R 1 represents R in general formula (1) and formula (2). 1 X and a are the same as those in general formula (2). (b) OCN-W-SiR 1 3-a X a A method of reacting an isocyanate alkylsilane compound represented by the formula: W is a divalent organic group. 1 represents R in general formula (1) and formula (2). 1X and a are the same as those in general formula (2). (c) After converting the terminal hydroxyl groups of the hydroxyl-terminated organic polymer to carbon-carbon unsaturated groups, the carbon-carbon unsaturated groups and HS-W-SiR 1 3-a X a A method of carrying out an ene-thiol reaction with a mercaptoalkylsilane compound represented by the formula: W is a divalent organic group. 1 represents R in general formula (1) and formula (2). 1 X and a are the same as those in general formula (2). (d) A hydroxyl-terminated organic polymer is reacted with a polyisocyanate compound to synthesize an NCO-terminated organic polymer, and then the terminal NCO groups are converted into an NCO-terminated organic polymer by the reaction of HNR 5 -W-SiR 1 3-a X a , or HS-W-SiR 1 3-a X a A method of reacting a silane compound represented by the formula: W is a divalent organic group. 5 is a hydrogen atom or an alkyl group. 1 represents R in general formula (1) and formula (2). 1 X and a are the same as those in general formula (2).

[0040] In the above methods (a) and (c), examples of the terminal carbon-carbon unsaturated group include a vinyl group, an allyl group, a methallyl group, an allenyl group, and a propargyl group.

[0041] In any of the above methods (b) to (d), the polymer (A) obtained by using a silane compound in which W is methylene exhibits very high curability.

[0042] Method (a) is preferred because it is easy to obtain a polymer (A) having good storage stability, while methods (b), (c), and (d) are preferred because they can achieve a high conversion rate in a relatively short reaction time.

[0043] The method for introducing a reactive silicon group by method (a) has been proposed in Japanese Patent Publication Nos. 45-36319, 46-12154, Japanese Patent Laid-Open Nos. 50-156599, 54-6096, 55-13767, 55-13468, 57-164123, Japanese Patent Publication No. 3-2450, U.S. Pat. Nos. 3,632,557, 4,345,053, 4,366,307, and 4,960,844. Examples of such methods include the method proposed in Japanese Patent Laid-Open Nos. 61-197631, 61-215622, 61-215623, and 61-218632, in which reactive silicon groups are introduced by hydrosilylation or the like into a high-molecular-weight, narrow-molecular-weight distribution polyoxypropylene polymer having a number-average molecular weight of 6,000 or more and an Mw / Mn ratio of 1.6 or less, as well as the method proposed in Japanese Patent Laid-Open No. 3-72527. Furthermore, a method for introducing more than one reactive silicon group into a molecular terminal is proposed in Japanese Patent No. 6,096,320.

[0044] The number average molecular weight of the polymer (A) is not particularly limited. The number average molecular weight of the polymer (A), as polystyrene-equivalent molecular weight measured by GPC, is preferably 3,000 to 100,000, more preferably 3,000 to 50,000, and particularly preferably 3,000 to 30,000. When the number average molecular weight is within the above range, the amount of reactive silicon groups introduced is appropriate, making it easy to obtain a polymer (A) that has a viscosity that is easy to handle and excellent workability, while keeping production costs within an appropriate range.

[0045] The molecular weight of polymer (A) can also be expressed as an end-group-converted molecular weight calculated by directly measuring the end-group concentration of a polymer precursor before the introduction of reactive silicon groups using titration analysis based on the principles of the hydroxyl value measurement method specified in JIS K 1557 and the iodine value measurement method specified in JIS K 0070, and taking into account the polymer structure (the degree of branching determined by the polymerization initiator used).The end-group-converted molecular weight of polymer (A) can also be calculated by creating a calibration curve of the number average molecular weight determined by general GPC measurement of the polymer precursor and the end-group-converted molecular weight, and converting the number average molecular weight determined by GPC of polymer (A) into an end-group-converted molecular weight.

[0046] The molecular weight distribution (Mw / Mn) of the polymer (A) is not particularly limited. It is preferable that the molecular weight distribution of the polymer (A) is narrow. Specifically, the molecular weight distribution is preferably 1.6 or less, more preferably 1.4 or less, even more preferably 1.3 or less, and particularly preferably 1.2 or less. The molecular weight distribution of the polymer (A) can be determined from the number average molecular weight and weight average molecular weight obtained by GPC measurement.

[0047] To obtain a good rubber-like cured product, the reactive silicon groups of the polymer (A) are preferably present at the polymer chain terminals. The average number of reactive silicon groups per polymer chain terminal is preferably 0.5 to 3.0, more preferably 0.6 to 2.5, even more preferably 0.7 to 2.2, and particularly preferably 0.8 to 2.0. When the number of reactive silicon groups is 0.5 or more, the curability of the polymer (A) and the sealant for paint substrate is good, and the cured product of the sealant for paint substrate has good rubber elasticity.

[0048] The number of reactive silicon groups in one molecule is preferably 1 to 7 on average, more preferably 1 to 4, and particularly preferably 1 to 3.

[0049] Furthermore, as described in WO2013 / 180203, an organic polymer having two or more reactive silicon groups at the polymer chain terminals can also be used as the polymer (A). Such a polymer (A) exhibits high curability, and the resulting cured product can be expected to have high strength and high recovery.

[0050] Specific examples of commercially available polymer (A) products include various reactive silicon group-containing polyoxypropylene products such as Kaneka MS Polymer (registered trademark) and Kaneka Silyl (registered trademark). All of these commercially available polymers (A) are products of Kaneka Corporation. Other usable products include EXCESTAR (registered trademark) from AGC Corporation, GENIOSIL (registered trademark) from WACKER, and STP from RISUN POLYMER.

[0051] <Epoxy compound (B)> The paint-undercoat sealant material contains an epoxy compound (B). The epoxy compound (B) has at least one epoxy group. The epoxy compound (B) may be a low-molecular-weight compound or a high-molecular-weight compound.

[0052] The epoxy compound (B) has an aromatic ring and / or a cycloalkane ring in its structure. The aromatic ring is not particularly limited as long as the desired effect is not impaired. Examples of the aromatic ring include aromatic hydrocarbon rings such as a benzene ring, a naphthalene ring, an anthracene ring, and a phenanthrene ring; non-benzene aromatic hydrocarbon rings; and heteroaromatic rings such as a pyridine ring and a pyrrole ring. The aromatic ring is preferably a benzene ring.

[0053] The cycloalkane ring is not particularly limited as long as the desired effect is not impaired. Examples of the cycloalkane ring include a monocyclic cycloalkane ring having 3 to 10 carbon atoms and a polycyclic cycloalkane ring having 7 to 12 carbon atoms. The cycloalkane ring is preferably a cyclohexane ring.

[0054] The epoxy compound (B) is not particularly limited as long as it has an aromatic ring and / or a cycloalkane ring and does not impair the desired effects. Examples of the epoxy compound (B) include bifunctional aromatic epoxy resins such as bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, bisphenol AD ​​type epoxy resins, naphthalene type epoxy resins, and biphenyl type epoxy resins; hydrogenated bisphenol type epoxy resins such as hydrogenated bisphenol A type epoxy resins, hydrogenated bisphenol F type epoxy resins, hydrogenated bisphenol S type epoxy resins, and hydrogenated bisphenol AD ​​type epoxy resins; phenol novolac type epoxy resins, brominated phenol novolac type epoxy resins, orthocresol novolac type epoxy resins, and the like. novolac epoxy resins such as bisphenol A novolac epoxy resins, and bisphenol AD ​​novolac epoxy resins; hydrogenated novolac epoxy resins obtained by hydrogenating the above-mentioned novolac epoxy resins; alicyclic epoxy resins such as epoxidized products of dicyclopentadiene phenolic resins; aromatic epoxy resins such as epoxidized products of naphthalene phenolic resins; and glycidylamine epoxy resins such as tetraglycidylaminodiphenylmethane, triglycidyl-p-aminophenol, tetraglycidyl metaxylylenediamine, and tetraglycidyl bisaminomethylcyclohexane. Regarding the above-mentioned epoxy compounds, compounds that do not fall under the category of polymers or polymeric compounds may be referred to as "epoxy resins" in accordance with the commonly used name.

[0055] The amount of the epoxy compound (B) used is preferably 0.1 to 10 parts by weight, more preferably 0.5 to 5 parts by weight, per 100 parts by weight of the total of the weight of the polyoxyalkylene polymer (A) and the weight of the (meth)acrylic polymer (D).

[0056] As the epoxy compound (B), commercially available products may be used. Specific examples of commercially available products of the epoxy compound (B) include jER (registered trademark) 828, jER (registered trademark) 806, jER (registered trademark) 806, jER (registered trademark) 152, jER (registered trademark) 157S70, jER (registered trademark) 871 (all manufactured by Mitsubishi Chemical Corporation), Epolite 4000, Epolite 3002(N), and Epolite (all manufactured by Kyoeisha Chemical Co., Ltd.).

[0057] <Aminosilane coupling agent (C) having a triethoxysilyl group> The paint-undercoat sealant contains an aminosilane coupling agent (C) having a triethoxysilyl group. The aminosilane coupling agent (C) is a compound having a triethoxysilyl group and a substituted or unsubstituted amino group in the molecule. The aminosilane coupling agent (C) can also function as an adhesion promoter, a dehydrating agent, a physical property adjuster, an agent for improving the dispersibility of inorganic fillers, etc.

[0058] The substituent in the substituted amino group is not particularly limited, and examples of the substituent include an alkyl group, an aralkyl group, and an aryl group.

[0059] Specific examples of the aminosilane coupling agent (C) include 3-aminopropyltriethoxysilane, 3-(2-aminoethylamino)propyltriethoxysilane, 3-ureidopropyltriethoxysilane, 3-(vinylbenzylamino)propyltriethoxysilane, N-cyclohexylaminomethyltriethoxysilane, and N-(1,3-dimethylbutylidene)-3-(triethoxysilyl)-1-propanamine. The aminosilane coupling agent (C) may be used alone or in combination of two or more. Furthermore, aminosilanes obtained by partially condensing triethoxysilyl groups to form oligomers are also suitable for use in terms of safety and stability. The aminosilanes to be condensed may be single or multiple. From the viewpoints of good storage stability and desired adhesion of the paint substrate sealant, 3-aminopropyltrimethoxysilane is preferred.

[0060] The lower limit of the content of the aminosilane coupling agent (C) is 0.1 parts by weight or more, preferably 0.3 parts by weight or more, and more preferably 0.5 parts by weight or more, relative to 100 parts by weight of the total weight of the polyoxyalkylene polymer (A) and the (meth)acrylic polymer (D), and the upper limit of the content of the aminosilane coupling agent (C) is 10 parts by weight or less, preferably 8 parts by weight or less, and more preferably 5 parts by weight or less.

[0061] Specific examples of commercially available aminosilane coupling agents (C) include KBE-903 (manufactured by Shin-Etsu Chemical Co., Ltd.) and Dynasylan (registered trademark) 1122 (manufactured by Evonik Industries AG).

[0062] <(Meth)acrylic polymer (D)> The paint-undercoat sealant preferably contains a (meth)acrylic polymer (D). The (meth)acrylic polymer (D) (hereinafter sometimes simply referred to as "polymer (D)") has a reactive silicon group. The reactive silicon group is not particularly limited as long as it can form a siloxane bond. The reactive silicon group is preferably a reactive silicon group represented by the above formula (2). The polymer backbone is a structure in which multiple structural units derived from monomers are bonded in succession. The monomer may be one type or multiple types.

[0063] The reactive silicon group in the polymer (D) may be the same as or different from the reactive silicon group in the polymer (A).

[0064] (Main chain structure of polymer (D)) The polymer (D) is not particularly limited. The polymer (D) preferably contains a structural unit derived from a (meth)acrylic acid alkyl ester. The polymer (D) may contain structural units derived from two or more types of (meth)acrylic acid alkyl esters. The (meth)acrylic acid alkyl ester means an acrylic acid alkyl ester and / or a methacrylic acid alkyl ester.

[0065] Specific examples of acrylic acid alkyl esters include methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, n-decyl acrylate, n-undecyl acrylate, lauryl acrylate, n-tridecyl acrylate, myristyl acrylate, cetyl acrylate, stearyl acrylate, and behenyl acrylate.

[0066] Specific examples of methacrylic acid alkyl esters include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, n-decyl methacrylate, n-undecyl methacrylate, lauryl methacrylate, n-tridecyl methacrylate, myristyl methacrylate, cetyl methacrylate, stearyl methacrylate, and behenyl methacrylate.

[0067] The ratio by weight of the structural units derived from alkyl (meth)acrylate to the weight of polymer (D) is preferably 50% by weight or more, and more preferably 70% by weight or more.

[0068] In terms of the compatibility of polymer (D) with polymer (A) and the like, and the stability of polymer (D), the monomer for preparing polymer (D) is preferably a (meth)acrylic acid alkyl ester having an alkyl group having 1 to 30 carbon atoms.

[0069] The (meth)acrylic acid alkyl ester having an alkyl group having 1 to 30 carbon atoms is represented by the following formula (D1): CH2=CR D1 COOR D2 (D1) (In formula (D1), R D1 is a hydrogen atom or a methyl group. D2 is an alkyl group having 1 to 30 carbon atoms. It is expressed as:

[0070] In formula (D1), R D2 Examples of the alkyl group include alkyl groups having 1 to 30 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, an n-butyl group, a tert-butyl group, a 2-ethylhexyl group, a lauryl group, an n-tridecyl group, a cetyl group, and a stearyl group. R D2 The alkyl group as the group preferably has 1 to 20 carbon atoms.

[0071] The monomers for producing the polymer (D) may contain other monomers in addition to the alkyl (meth)acrylate ester. Other monomers include acrylic acid and methacrylic acid; (meth)acrylamides such as acrylamide, methacrylamide, N-methylolacrylamide, and N-methylolmethacrylamide; epoxy group-containing (meth)acrylic acid esters such as glycidyl acrylate and glycidyl methacrylate; amino group-containing unsaturated compounds such as 2-(N,N-diethylamino)ethyl methacrylate and 2-aminoethyl vinyl ether; acrylonitrile and methacrylonitrile; styrenes such as styrene and α-methylstyrene; alkyl vinyl ethers; vinyl chloride; and fatty acid vinyl esters such as vinyl acetate and vinyl propionate.

[0072] The molecular weight of the polymer (D) is not particularly limited as long as the desired effects are not impaired. The molecular weight of the (meth)acrylic copolymer (D) is preferably 500 to 100,000, more preferably 1,000 to 30,000, in terms of polystyrene equivalent number average molecular weight measured by GPC.

[0073] The polymer (D) can be produced by a conventional vinyl polymerization method. Examples of the vinyl polymerization method include a solution polymerization method using a radical reaction and a bulk polymerization method. The vinyl polymerization method is not limited to these methods. The above polymerization reaction is typically carried out at 50 to 150° C. in the presence of monomers, a radical initiator, a chain transfer agent, a solvent, and the like. The polymerization reaction conditions are not limited to the above conditions.

[0074] Specific examples of the radical initiator include azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), and benzoyl peroxide.

[0075] Specific examples of the chain transfer agent include mercaptans such as n-dodecyl mercaptan, tert-dodecyl mercaptan, and lauryl mercaptan, and halogen-containing compounds.

[0076] As the solvent, for example, a solvent inactive to the polymerization reaction, such as an alcohol-based solvent, an ether-based solvent, a hydrocarbon-based solvent, or an ester-based solvent, can be preferably used. The solvents may be used alone or in combination of two or more.

[0077] Various methods are known for introducing reactive silicon groups into (meth)acrylic polymers. Specific examples include: I) A method of copolymerizing a compound having an ethylenically unsaturated double bond and a reactive silicon group with a (meth)acrylic acid alkyl ester represented by formula (D1); II) A method in which a compound having an ethylenically unsaturated double bond and a reactive functional group (e.g., acrylic acid) is copolymerized with a (meth)acrylic acid alkyl ester represented by formula (D1), and the reactive functional group in the copolymer is reacted with a reactive silicon and a compound capable of reacting with the reactive group (e.g., a reactive silicon group-containing isocyanate compound); III) A method of polymerizing a (meth)acrylic acid alkyl ester represented by formula (D1) in the presence of a mercaptan having a reactive silicon group as a chain transfer agent; VI) A method of polymerizing an alkyl (meth)acrylate represented by formula (D1) using an azobisnitrile compound having a reactive silicon group or a disulfide compound having a reactive silicon group as an initiator; and V) A method of introducing a reactive silicon group into the molecular chain terminal of a polymer obtained by polymerizing an alkyl (meth)acrylate ester represented by formula (D1) by living radical polymerization can be mentioned. The method for introducing a reactive silicon group into a (meth)acrylic polymer is not limited to the above-mentioned method.

[0078] The compound having an ethylenically unsaturated double bond and a reactive silicon group used in the above method I) includes compounds represented by the following formula (D2): CH2=CR D5 COOR D6 -SiR 1 3-a X a (D2) (In formula (D2), R 1 , X, and a are R in formula (2). 1 , X, and a. R D5 is a hydrogen atom or a methyl group. D6 is an alkylene group having 1 to 6 carbon atoms. A compound represented by the following formula is preferred.

[0079] In formula (D2), R D6 The alkylene group as is an alkylene group having 1 to 6 carbon atoms such as a methylene group, an ethane-1,2-diyl group (ethylene group), and a propane-1,3-diyl group (trimethylene group), and is preferably an alkylene group having 1 to 4 carbon atoms.

[0080] Specific examples of compounds having an ethylenically unsaturated double bond and a reactive silicon group include γ-methacryloxypropylalkoxysilanes such as γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, and γ-methacryloxypropyltriethoxysilane; γ-acryloxypropylalkoxysilanes such as γ-acryloxypropyltrimethoxysilane, γ-acryloxypropylmethyldimethoxysilane, and γ-acryloxypropyltriethoxysilane; and vinylalkoxysilanes such as vinyltrimethoxysilane, vinylmethyldimethoxysilane, and vinyltriethoxysilane.

[0081] In the compound having an ethylenically unsaturated double bond and a reactive functional group used in the above method II), examples of the reactive functional group include an amino group, a hydroxyl group, and a carboxyl group. Examples of groups that can react with these reactive functional groups include an isocyanate group. Other examples include allyl groups as reactive functional groups, as described in JP-A-54-36395, JP-A-01-272654, and JP-A-02-214759, etc. Examples of groups that can react with allyl groups include silicon hydride groups (H—Si).

[0082] Examples of mercaptans containing a reactive silicon group that can be used as chain transfer agents in the above method III) include γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, and γ-mercaptopropyltriethoxysilane.

[0083] Examples of the azobisnitrile compound having a reactive silicon group and the disulfide compound used in the above method IV) include the azobisnitrile compound having an alkoxysilyl group and the disulfide compound having an alkoxysilyl group described in JP-A-60-23405 and JP-A-62-70405.

[0084] The above method V) includes the method described in JP-A-09-272714.

[0085] Other methods include those described in JP-A Nos. 59-168014 and 60-228516, which use a mercaptan having a reactive silicon group in combination with a radical polymerization initiator having a reactive silicon group.

[0086] The number of reactive silicon groups contained in the polymer (D) is not particularly limited, and the average number of reactive silicon groups contained in the polymer (D) is preferably 0.1 to 3.0, more preferably 0.5 to 2.0, per molecule.

[0087] Weight W of polymer (D) D Weight W of polymer (A) A Ratio of W A / W D is not particularly limited as long as the desired effect is obtained. A / W D The ratio may be 1 / 99 to 100 / 0, 20 / 80 to 80 / 20, or 30 / 70 to 70 / 30.

[0088] It is common knowledge among those skilled in the art that the monomer composition of the polymer (D) is selected depending on the application and purpose of the paint-undercoat sealant material. When the paint-undercoat sealant is used for applications requiring strength, it is preferable that the polymer (D) has a relatively high glass transition temperature (Tg). Specifically, the Tg of the polymer (D) is preferably 0 to 200° C., more preferably 20 to 100° C. The Tg can be calculated using the Fox formula below.

[0089] Fox's formula: 1 / (Tg(K))=Σ(Mi / Tgi) (In the formula, Mi is the weight fraction of the monomer i component constituting the polymer, and Tgi is the glass transition temperature (K) of the homopolymer of monomer i.)

[0090] For example, polymethyl methacrylate is known as a (meth)acrylic polymer with a relatively high glass transition temperature (Tg). Therefore, in the monomers used to produce polymer (D), the higher the weight ratio of methyl methacrylate to the weight of the monomer, the higher the glass transition temperature (Tg) of polymer (D) tends to be. Conversely, the lower the weight ratio of methyl methacrylate to the weight of the monomer, the lower the glass transition temperature (Tg) of polymer (D) tends to be. It is preferable that the weight ratio of methyl methacrylate to the weight of the monomers used in producing the polymer (D) is 50% or more, since this makes it easier to form a high-strength cured product. It is preferable that the ratio by weight of methyl methacrylate to the weight of the monomers used in producing the polymer (D) is less than 50%, since this results in a low viscosity and good workability of the paint-undercoat sealant material.

[0091] <Curing catalyst (E)> The paint-undercoat sealant preferably contains a curing catalyst (E) for the purpose of promoting the hydrolysis condensation reaction between the reactive silicon groups of the polymer (A) and the polymer (D) and chain-extending or cross-linking the polymer. The curing catalyst (E) is not particularly limited as long as it can chain-extend or cross-link the polymer and does not fall under the category of the aminosilane coupling agent (C). Examples of the curing catalyst (E) include a silanol condensation catalyst. Examples of the silanol condensation catalyst include organotin compounds, metal carboxylates, carboxylic acids, alkoxy metals, Lewis acids, and amine compounds other than the aminosilane coupling agents (C). As the curing catalyst (E), organotin compounds, metal carboxylates, carboxylic acids, alkoxy metals, and amine compounds other than the aminosilane coupling agents (C) are preferred, and organotin compounds are more preferred.

[0092] Specific examples of organotin compounds include dibutyltin dilaurate, dibutyltin dioctanoate, dibutyltin bis(butyl maleate), dibutyltin diacetate, dibutyltin oxide, dibutyltin diacetylacetonate, dioctyltin diacetylacetonate, dioctyltin dilaurate, dioctyltin distearate, dioctyltin diacetate, dioctyltin oxide, a reaction product of dibutyltin oxide with a silicate compound, a reaction product of dioctyltin oxide with a silicate compound, and a reaction product of dibutyltin oxide with a phthalate ester.

[0093] Specific examples of the metal carboxylate include tin carboxylate, bismuth carboxylate, titanium carboxylate, zirconium carboxylate, iron carboxylate, etc. Furthermore, as the metal carboxylate, salts of the following carboxylic acids combined with various metals can be used.

[0094] Specific examples of the amine compound other than the aminosilane coupling agent (C) include amines such as octylamine, 2-ethylhexylamine, laurylamine, and stearylamine; nitrogen-containing heterocyclic compounds such as pyridine, 1,8-diazabicyclo[5,4,0]undecene-7 (DBU), and 1,5-diazabicyclo[4,3,0]nonene-5 (DBN); guanidines such as guanidine, phenylguanidine, and diphenylguanidine; biguanides such as butylbiguanide, 1-o-tolylbiguanide, and 1-phenylbiguanide; amino group-containing silane coupling agents other than the aminosilane coupling agent (C); and ketimine compounds.

[0095] Specific examples of carboxylic acids include acetic acid, propionic acid, butyric acid, 2-ethylhexanoic acid, lauric acid, stearic acid, oleic acid, linoleic acid, neodecanoic acid, and versatic acid.

[0096] Specific examples of alkoxy metals include titanium compounds such as tetrabutyl titanate, titanium tetrakis(acetylacetonate), and diisopropoxytitanium bis(ethylacetoacetate); aluminum compounds such as aluminum tris(acetylacetonate) and diisopropoxyaluminum ethylacetoacetate; and zirconium compounds such as zirconium tetrakis(acetylacetonate). Other silanol condensation catalysts that can be used include fluorine anion-containing compounds, photoacid generators, and photobase generators. Two or more different silanol condensation catalysts may be used in combination. The amount of the silanol condensation catalyst used is preferably 0.001 to 20 parts by weight, more preferably 0.01 to 15 parts by weight, and particularly preferably 0.01 to 10 parts by weight, per 100 parts by weight of the total of the weight of the polyoxyalkylene polymer (A) and the weight of the (meth)acrylic polymer (D).

[0097] <Other additives> The paint-undercoat sealant may contain various additives in addition to the polyoxyalkylene polymer (A), epoxy compound (B), and aminosilane coupling agent (C) to the extent that the desired effects are not impaired. Examples of other additives include fillers, adhesion promoters, plasticizers, solvents, diluents, thixotropy-imparting agents, antioxidants, light stabilizers, ultraviolet absorbers, physical property adjusters, tackifying resins, epoxy group-containing compounds, photocurable substances, oxygen-curable substances, epoxy resins, other resins, surface property improvers, foaming agents, curability adjusters, flame retardants, silicates, radical inhibitors, metal deactivators, phosphorus-based peroxide decomposers, lubricants, pigments, and mildew inhibitors.

[0098] (filler) The paint-undercoat sealant may contain various fillers, such as reinforcing fillers such as fumed silica, precipitated silica, crystalline silica, fused silica, dolomite, anhydrous silicic acid, hydrous silicic acid, and carbon black; heavy calcium carbonate, colloidal calcium carbonate, magnesium carbonate, diatomaceous earth, calcined clay, clay, talc, titanium oxide, bentonite, organic bentonite, ferric oxide, fine aluminum powder, flint powder, zinc oxide, activated zinc oxide, and resin powder; and fibrous fillers such as asbestos, glass fiber, and filaments. Examples of resin powder include PVC powder and PMMA powder. When a filler is used, the amount of the filler used is preferably 1 to 300 parts by weight, more preferably 10 to 200 parts by weight, per 100 parts by weight of the total of the weight of the polyoxyalkylene polymer (A) and the weight of the (meth)acrylic polymer (D).

[0099] When it is desired to obtain a cured product having high strength by using these fillers, fillers selected from the group consisting of fumed silica, precipitated silica, crystalline silica, fused silica, dolomite, silicic acid anhydride, hydrated silicic acid, carbon black, surface-treated fine calcium carbonate, calcined clay, clay, and activated zinc oxide are preferably used. The amount of these fillers used, which is preferable in terms of the strength of the cured product, is preferably 1 to 200 parts by weight per 100 parts by weight of the total weight of the polyoxyalkylene polymer (A) and the (meth)acrylic polymer (D). Furthermore, when a cured product with low strength and high elongation at break is desired, fillers selected from titanium oxide, calcium carbonate, magnesium carbonate, talc, ferric oxide, zinc oxide, shirasu balloon, and the like can be preferably used. The amount of these fillers used, which is preferable in terms of the elongation at break of the cured product, is preferably 5 to 200 parts by weight per 100 parts by weight of the total weight of the polyoxyalkylene polymer (A) and the (meth)acrylic polymer (D).

[0100] Generally, the larger the specific surface area of ​​calcium carbonate, the greater the effect of improving the breaking strength, breaking elongation, and adhesiveness of the cured product. These fillers can be used alone or in combination with two or more types. Fatty acid surface-treated colloidal calcium carbonate can be used in combination with calcium carbonate with a particle size of 1 μm or more, such as untreated ground calcium carbonate.

[0101] The paint-undercoat sealant material may contain spherical hollow bodies such as balloons in order to reduce the weight (specific gravity) of the cured product. Balloons are hollow spherical fillers. Examples of balloon materials include inorganic materials such as glass, shirasu, and silica, and organic materials such as phenolic resin, urea resin, polystyrene, saran, and acrylonitrile. The balloon material is not limited to these materials. The balloon material may also be a composite material composed of an inorganic material and an organic material. The balloon material may also be a laminate of multiple layers. One type of balloon may be used alone, or two or more types may be used in combination. The surface of the balloon may be surface-treated, coated, or treated with various surface treatment agents. For example, organic balloons coated with calcium carbonate, talc, titanium oxide, etc., or inorganic balloons surface-treated with a silane coupling agent may be used.

[0102] The particle size of the balloons is preferably 3 μm to 200 μm, and particularly preferably 10 μm to 110 μm. When the particle size of the balloons is within this range, the use of an appropriate amount of balloons can reduce the weight of the cured product to a desired extent, and a cured product can be formed while suppressing the occurrence of surface irregularities and a decrease in elongation.

[0103] When using balloons, an anti-slip agent such as that described in JP 2000-154368 A or an amine compound other than the aminosilane coupling agent (C) can be added to the paint base sealant material to impart a matte finish to the surface of the cured product by adding an uneven texture to the surface as described in JP 2001-164237 A. As the amine compound other than the aminosilane coupling agent (C), primary and / or secondary amines having a melting point of 35°C or higher are particularly preferred.

[0104] Specific examples of balloons are described in JP-A Nos. 2-129262, 4-8788, 4-173867, 5-1225, 7-113073, 9-53063, 10-251618, 2000-154368, 2001-164237, WO97 / 05201, and the like.

[0105] The amount of spherical hollow bodies (balloons) used is preferably 0.01 to 30 parts by weight per 100 parts by weight of the total of the weight of the polyoxyalkylene polymer (A) and the weight of the (meth)acrylic polymer (D). The lower limit is more preferably 0.1 part by weight, and the upper limit is more preferably 20 parts by weight. When the amount of spherical hollow bodies is within the above range, the paint substrate sealant has good properties and is likely to form a cured product excellent in elongation and breaking strength.

[0106] (adhesion imparting agent) The paint-undercoat sealant may contain an adhesion promoter. Examples of the adhesion promoter include the epoxy compound (B) and a silane coupling agent other than the aminosilane coupling agent (C). Silane coupling agents are compounds having a hydrolyzable silicon group and a functional group other than the hydrolyzable silicon group within the molecule. When a paint base sealant is applied to various adherends, such as inorganic substrates such as glass, aluminum, stainless steel, zinc, copper, and mortar, or organic substrates such as vinyl chloride, acrylic, polyester, polyethylene, polypropylene, and polycarbonate, the use of a silane coupling agent exhibits a significant improvement in adhesion under non-primer or primer-treated conditions. When a paint base sealant is used under non-primer conditions, the effect of improving adhesion to various adherends is particularly significant. In addition to the above functions, silane coupling agents can also function as dehydrating agents, property adjusters, and inorganic filler dispersibility improvers.

[0107] The hydrolyzable group in the hydrolyzable silicon group contained in other silane coupling agents is not particularly limited. Examples of hydrolyzable groups include hydrogen atoms, halogen atoms, alkoxy groups, aryloxy groups, alkenyloxy groups, acyloxy groups, ketoximate groups, amino groups, amide groups, acid amide groups, aminooxy groups, and mercapto groups. Among these, halogen atoms, alkoxy groups, alkenyloxy groups, and aryloxy groups are preferred due to their high activity. Chlorine atoms and alkoxy groups are preferred because they are easily introduced into silane coupling agents. Alkoxy groups such as methoxy groups and ethoxy groups are more preferred because of their mild hydrolysis and ease of handling, with methoxy groups and ethoxy groups being particularly preferred. Furthermore, ethoxy groups and isopropenyloxy groups are preferred from the standpoint of safety, as the compounds that are eliminated by reaction are ethanol and acetone, respectively. The number of hydrolyzable groups bonded to silicon atoms in a silane coupling agent may be preferably three to ensure good adhesion. Furthermore, two may be preferable to ensure the storage stability of paint substrate sealants.

[0108] When using other silane coupling agents as adhesion promoters, aminosilane coupling agents other than the aminosilane coupling agent (C) that have a hydrolyzable silicon group and a substituted or unsubstituted amino group are preferred because they have a significant adhesiveness improving effect. The substituent in the substituted amino group is not particularly limited. Examples of the substituent include an alkyl group, an aralkyl group, and an aryl group.

[0109] Specific examples of other aminosilane coupling agents include 3-aminopropyltrimethoxysilane, 3-aminopropyltriisopropoxysilane, 3-aminopropylmethyldimethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-(2-aminoethylamino)propyltrimethoxysilane, 3-(2-aminoethylamino)propylmethyldimethoxysilane, 3-(2-aminoethylamino)propylmethyldiethoxysilane, 3-(2-aminoethylamino)propyltriisopropoxysilane, 3-(2-(2-aminoethylamino)ethylamino)propyltrimethoxysilane, 3-(6-aminohexylamino)propyltrimethylsilane, Examples of the silanes include amino group-containing silanes such as trimethoxysilane, 3-ethylamino-2-methylpropyltrimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-phenylaminopropyltrimethoxysilane, 3-benzylaminopropyltrimethoxysilane, N-cyclohexylaminomethyldiethoxymethylsilane, N-phenylaminomethyltrimethoxysilane, N-butylaminopropyltrimethoxysilane, (2-aminoethylamino)methyltrimethoxysilane, N,N'-bis[3-(trimethoxysilyl)propyl]ethylenediamine, and bis(trimethoxysilylpropyl)amine; and ketimine-type silanes.

[0110] Among these, 3-aminopropyltrimethoxysilane, 3-(2-aminoethylamino)propyltrimethoxysilane, and 3-(2-aminoethylamino)propylmethyldimethoxysilane are preferred in terms of good adhesiveness of the cured product. Other aminosilane coupling agents may be used alone or in combination of two or more. It has been noted that 3-(2-aminoethylamino)propyltrimethoxysilane is more irritating than other aminosilanes. The irritating effect can be alleviated by using 3-aminopropyltrimethoxysilane in combination with 3-(2-aminoethylamino)propyltrimethoxysilane instead of reducing the amount of 3-(2-aminoethylamino)propyltrimethoxysilane. Furthermore, silane coupling agents oligomerized by partial condensation of hydrolyzable silicon groups are also suitable in terms of safety and stability. The condensed silane coupling agents may be a single type or multiple types. Examples of oligomerized silane coupling agents include Dynasylan 1146 from Evonik. In terms of good storage stability of the paint-undercoat sealant material, 3-aminopropyltrimethoxysilane and 3-(2-aminoethylamino)propylmethyldimethoxysilane are preferred.

[0111] Specific examples of the silane coupling agent other than the other aminosilane coupling agent include epoxy group-containing silane coupling agents other than the epoxy compound (B), such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, and 3-glycidoxypropylmethyldimethoxysilane; isocyanate group-containing silane coupling agents such as 3-isocyanatepropyltrimethoxysilane, 3-isocyanatepropyltriethoxysilane, 3-isocyanatepropylmethyldiethoxysilane, 3-isocyanatepropylmethyldimethoxysilane, (isocyanatemethyl)trimethoxysilane, and (isocyanatemethyl)dimethoxymethylsilane; and 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane. Examples of suitable coupling agents include mercapto group-containing silane coupling agents such as mercaptomethyltriethoxysilane, 3-mercaptopropylmethyldiethoxysilane, and mercaptomethyltriethoxysilane; carboxysilane coupling agents such as 2-carboxyethyltriethoxysilane, 2-carboxyethylphenylbis(2-methoxyethoxy)silane, and N-2-(carboxymethylamino)ethyl-3-aminopropyltrimethoxysilane; vinyl-type unsaturated group-containing silane coupling agents such as vinyltrimethoxysilane, vinyltriethoxysilane, 3-methacryloyloxypropylmethyldimethoxysilane, and 3-acryloyloxypropylmethyltriethoxysilane; halogen-containing silane coupling agents such as 3-chloropropyltrimethoxysilane; and isocyanurate silane coupling agents such as tris(trimethoxysilyl)isocyanurate. Condensates obtained by partially condensing the above silane coupling agents can also be used. Examples of such condensates include Dynasylan 6490 and Dynasylan 6498 from Evonik. Furthermore, modified derivatives of these compounds, such as amino-modified silyl polymers, silylated amino polymers, unsaturated aminosilane complexes, phenylamino long-chain alkylsilanes, aminosilylated silicones, and silylated polyesters, can also be used as other silane coupling agents.

[0112] Of these, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, and 3-glycidoxypropylmethyldimethoxysilane are preferred in terms of good adhesiveness of the cured product.

[0113] The silane coupling agents may be used alone or in combination of two or more. The amount of the other silane coupling agent used is preferably 0.1 to 20 parts by weight, more preferably 0.5 to 10 parts by weight, per 100 parts by weight of the total of the weight of the polyoxyalkylene polymer (A) and the weight of the (meth)acrylic polymer (D).

[0114] (plasticizer) The paint-under-surface sealant may contain a plasticizer, which can adjust the viscosity and slump of the paint-under-surface sealant, as well as the mechanical properties such as tensile strength and elongation of the cured product.

[0115] Specific examples of the plasticizer include phthalate ester compounds such as dibutyl phthalate, diisononyl phthalate (DINP), diheptyl phthalate, di(2-ethylhexyl) phthalate, diisodecyl phthalate (DIDP), and butyl benzyl phthalate; terephthalate compounds such as bis(2-ethylhexyl)-1,4-benzenedicarboxylate; hydrogenated phthalate compounds such as 1,2-cyclohexanedicarboxylic acid diisononyl ester; dioctyl adipate, dioctyl sebacate, dibutyl sebacate, diisodecyl succinate, and aliphatic polycarboxylic acid ester compounds such as acetyl tributyl citrate; unsaturated fatty acid ester compounds such as butyl oleate and methyl acetylricinoleate; alkylsulfonic acid phenyl esters; phosphate ester compounds such as tricresyl phosphate and tributyl phosphate; trimellitic acid ester compounds; chlorinated paraffins; hydrocarbon oils such as alkyl diphenyls and partially hydrogenated terphenyls; process oils; epoxidized soybean oil, and epoxy plasticizers other than the epoxy compound (B), such as epoxy benzyl stearate. A specific example of a terephthalic acid ester compound is EASTMAN168 (trade name, manufactured by EASTMAN CHEMICAL). A specific example of a non-phthalic acid ester compound is Hexamoll DINCH (trade name, manufactured by BASF). A specific example of an alkylsulfonic acid phenyl ester is Mesamoll (trade name, manufactured by LANXESS).

[0116] Polymeric plasticizers can also be used. The use of polymeric plasticizers allows the initial physical properties of the cured product to be maintained for a longer period of time than when low-molecular-weight plasticizers are used. Furthermore, the drying properties (paintability) of the cured product when coated with an alkyd paint are improved.

[0117] Specific examples of polymeric plasticizers include vinyl polymers, which are polymers of vinyl monomers; esters of polyalkylene glycols and polyols, such as diethylene glycol dibenzoate, triethylene glycol dibenzoate, and pentaerythritol ester; polyester plasticizers obtained from dibasic acids, such as sebacic acid, adipic acid, azelaic acid, and phthalic acid, and dihydric alcohols, such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, and dipropylene glycol; polyether polyols (polyoxyalkylene compounds), such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol, having a number-average molecular weight of 500 or more, or even 1,000 or more; derivatives of these polyether polyols in which the hydroxyl groups have been converted to ester groups, ether groups, or the like; polystyrenes, such as poly-α-methylstyrene; polybutadiene, polybutene, polyisobutylene, butadiene-acrylonitrile, and polychloroprene. Polymeric plasticizers are not limited to these.

[0118] The polymeric plasticizer is preferably compatible with the polyoxyalkylene polymer (A) and / or the (meth)acrylic polymer (D). From this viewpoint, polyethers and vinyl polymers are preferred. When polyethers are used as plasticizers, surface curability and deep curability are improved, and curing delay after storage does not occur. Among polyethers, polypropylene glycol is more preferred. Vinyl polymers are preferred from the viewpoint of compatibility with the polyoxyalkylene polymer (A) and / or the (meth)acrylic polymer (D) and the weather resistance and heat resistance of the cured product. Among vinyl polymers, acrylic polymers and / or methacrylic polymers are preferred, and acrylic polymers such as polyacrylic acid alkyl esters are more preferred. As a method for synthesizing vinyl polymers, living radical polymerization is preferred, and atom transfer radical polymerization is more preferred, because it produces polymers with narrow molecular weight distributions and low viscosity. Furthermore, the so-called SGO process, which is described in Japanese Patent Application Laid-Open No. 2001-207157 and involves continuous bulk polymerization of an acrylic acid alkyl ester monomer at high temperature and pressure, is also preferred as a method for producing a vinyl polymer.

[0119] The number average molecular weight of the polymer plasticizer is preferably 500 to 15,000, more preferably 800 to 10,000, still more preferably 1,000 to 8,000, particularly preferably 1,000 to 5,000, and most preferably 1,000 to 3,000. When the number average molecular weight of the polymer plasticizer is within the above range, the initial physical properties of the cured product can be maintained over a long period of time while suppressing the outflow of the plasticizer from the cured product over time due to heat, rainfall, etc., and the paint base sealant material has an appropriate viscosity and good workability. The molecular weight distribution of the polymeric plasticizer is not particularly limited, but is preferably narrow. Specifically, the molecular weight distribution is preferably less than 1.80, more preferably 1.70 or less, even more preferably 1.60 or less, still more preferably 1.50 or less, particularly preferably 1.40 or less, and most preferably 1.30 or less.

[0120] The number average molecular weight of vinyl polymers is measured by GPC. The number average molecular weight of polyether polymers is measured by end group analysis. The molecular weight distribution (Mw / Mn) is measured by GPC (polystyrene equivalent).

[0121] The polymeric plasticizer may or may not have a reactive silicon group. When the polymeric plasticizer has a reactive silicon group, it acts as a reactive plasticizer and can prevent the plasticizer from migrating from the cured product. When the polymeric plasticizer has a reactive silicon group, the number of reactive silicon groups per molecule is preferably 1 or less, more preferably 0.8 or less, on average. When using a plasticizer having a reactive silicon group, particularly a polyether polymer having a reactive silicon group, its number average molecular weight must be lower than the number average molecular weight of the polyoxyalkylene polymer (A) and / or the number average molecular weight of the (meth)acrylic polymer (D).

[0122] Among the plasticizers described above, at least one selected from the group consisting of phthalate esters, hydrogenated phthalate esters, and polyoxyalkylene compounds is preferred.

[0123] The amount of plasticizer used is preferably 5 to 150 parts by weight, more preferably 10 to 120 parts by weight, and even more preferably 20 to 100 parts by weight, per 100 parts by weight of the total weight of the polyoxyalkylene polymer (A) and the (meth)acrylic polymer (D). When the amount of plasticizer used is within the above range, it is possible to obtain the desired effects of using the plasticizer sufficiently, while forming a cured product excellent in mechanical strength. The plasticizer may be used alone, or two or more types may be used in combination. A low-molecular-weight plasticizer may be used in combination with a polymeric plasticizer. These plasticizers may be blended with the polyoxyalkylene polymer (A) or the (meth)acrylic polymer (D) when producing the polyoxyalkylene polymer (A) or the (meth)acrylic polymer (D).

[0124] (solvents, diluents) The paint base sealant may contain a solvent or a diluent. The solvent and diluent are not particularly limited. Examples of solvents and diluents that can be used include aliphatic hydrocarbons, aromatic hydrocarbons, alicyclic hydrocarbons, halogenated hydrocarbons, alcohols, esters, ketones, and ethers. When using a solvent or a diluent, the boiling point of the solvent is preferably 150°C or higher, more preferably 200°C or higher, and particularly preferably 250°C or higher, in order to prevent air pollution when the paint base sealant is used indoors. The above solvents or diluents may be used alone or in combination of two or more.

[0125] (thixotropic agent) The paint base sealant may contain a thixotropic agent, if necessary, to prevent sagging and improve workability. The thixotropic agent is not particularly limited. Examples of thixotropic agents include polyamide waxes; hydrogenated castor oil derivatives; and metal soaps such as calcium stearate, aluminum stearate, and barium stearate. Examples of trade names include Disparlon 6500, Disparlon 308, Disparlon 6300, Crayvallac SL, and Crayvallac SLT. These thixotropic agents may be used alone or in combination. The amount of the thixotropy-imparting agent used is preferably 0.1 to 20 parts by weight per 100 parts by weight of the total of the weight of the polyoxyalkylene polymer (A) and the weight of the (meth)acrylic polymer (D).

[0126] (antioxidant) The paint-undercoat sealant may contain an antioxidant (anti-aging agent). The use of an antioxidant can improve the weather resistance of the cured product. Examples of antioxidants include hindered phenol compounds, monophenol compounds, bisphenol compounds, and polyphenol compounds, with hindered phenol compounds being particularly preferred. Examples of antioxidants include Irganox 245, Irganox 1010, Irganox 1035, Irganox 1076, Irganox 1135, Irganox 1330, and Irganox 1520 (all manufactured by BASF); SONGNOX 1076 (manufactured by SONGWON), and BHT. Hindered amine light stabilizers such as TINUVIN 622LD, TINUVIN 144, TINUVIN 292, CHIMASSORB944LD, and CHIMASSORB119FL (all manufactured by BASF); ADK STAB LA-57, ADK STAB LA-62, ADK STAB LA-67, ADK STAB LA-63P, and ADK STAB LA-68 (all manufactured by ADEKA Corporation); SANOL LS-2626, SANOL LS-1114, and SANOL LS-744 (all manufactured by Sankyo Lifetech Co., Ltd.); and NOCRAC CD (manufactured by Ouchi Shinko Chemical Industry Co., Ltd.) can also be used. Other antioxidants that can be used include SONGNOX 4120, Naugard 445, and OKABEST CLX050. Specific examples of antioxidants are also described in Japanese Patent Application Laid-Open Nos. 4-283259 and 9-194731. The amount of the antioxidant used is preferably 0.1 to 10 parts by weight, more preferably 0.2 to 5 parts by weight, per 100 parts by weight of the total of the weight of the polyoxyalkylene polymer (A) and the weight of the (meth)acrylic polymer (D).

[0127] (light stabilizer) The paint-undercoat sealant may contain a light stabilizer. The use of a light stabilizer can prevent photooxidation degradation of the cured product. Examples of light stabilizers include benzotriazole-based compounds, hindered amine-based compounds, and benzoate-based compounds. Hindered amine-based compounds are particularly preferred as light stabilizers. The amount of the light stabilizer used is preferably 0.1 to 10 parts by weight, more preferably 0.2 to 5 parts by weight, per 100 parts by weight of the total of the polyoxyalkylene polymer (A) and the (meth)acrylic polymer (D). Specific examples of light stabilizers are described in, for example, JP-A-9-194731.

[0128] When a photocurable substance is incorporated into a paint base sealant, particularly when an unsaturated acrylic compound is used, it is preferable to use a tertiary amine-containing hindered amine light stabilizer as the hindered amine light stabilizer in order to improve the storage stability of the paint base sealant, as described in JP-A-5-70531. Tertiary amine-containing hindered amine light stabilizers include TINUVIN 123, TINUVIN 144, TINUVIN 249, TINUVIN 292, TINUVIN 312, TINUVIN 622LD, TINUVIN 765, TINUVIN 770, TINUVIN 880, TINUVIN 5866, TINUVIN B97, CHIMASSORB119FL, and CHIMASSORB944LD (all manufactured by BASF); ADK STAB LA-57, LA-62, LA-63, LA-67, and LA-68 (all manufactured by ADEKA Corporation); SANOL LS-292, LS-2626, LS-765, LS-744, and LS-1114 (all manufactured by Sankyo Lifetech Co., Ltd.), SABOSTAB UV91, SABOSTAB UV119, SONGSORB CS5100, SONGSORB CS622, and SONGSORB Examples include CS944 (all manufactured by SONGWON) and Nocrac CD (manufactured by Ouchi Shinko Chemical Industry Co., Ltd.).

[0129] (ultraviolet absorber) The paint base sealant may contain an ultraviolet absorber. The use of an ultraviolet absorber can improve the surface weather resistance of the cured product. Examples of ultraviolet absorbers include benzophenone-based compounds, benzotriazole-based compounds, salicylate-based compounds, triazine-based compounds, substituted tolyl-based compounds, and metal chelate-based compounds. Among these, benzotriazole-based compounds are particularly preferred. Specific examples of benzotriazole-based compounds include Tinuvin 234, Tinuvin 326, Tinuvin 327, Tinuvin 328, Tinuvin 329, Tinuvin 350, Tinuvin 571, Tinuvin 900, Tinuvin 928, Tinuvin 1130, and Tinuvin 1600 (all manufactured by BASF); and SONGSORB 3290 (manufactured by SONGWON). Specific examples of triazine compounds include TINUVIN 400, TINUVIN 405, TINUVIN 477, and TINUVIN 1577ED (all manufactured by BASF), and SONGSORB CS400 and SONGSORB 1577 (manufactured by SONGWON).Specific examples of benzophenone compounds include SONGSORB 8100 (manufactured by SONGWON). The amount of the ultraviolet absorber used is preferably 0.1 to 10 parts by weight, more preferably 0.2 to 5 parts by weight, based on 100 parts by weight of the total of the polyoxyalkylene polymer (A) and the (meth)acrylic polymer (D). It is preferable to use a phenolic antioxidant or a hindered phenolic antioxidant in combination with a hindered amine light stabilizer and a benzotriazole ultraviolet absorber. Addworks IBC760 (manufactured by Clariant) can be used as a product containing a mixture of antioxidants, light stabilizers, and UV absorbers.

[0130] (Physical property adjuster) The paint-undercoat sealant may optionally contain a physical property adjuster to adjust the tensile properties of the cured product. The physical property adjuster is not particularly limited as long as it is a compound other than the epoxy compound (B) and the aminosilane coupling agent (C). Examples of the physical property adjuster include alkylalkoxysilanes such as methyltrimethoxysilane, dimethyldimethoxysilane, trimethylmethoxysilane, and n-propyltrimethoxysilane; alkylisopropenoxysilanes such as dimethyldiisopropenoxysilane, methyltriisopropenoxysilane, and 3-glycidoxypropylmethyldiisopropenoxysilane; alkoxysilanes having functional groups such as 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, vinyltrimethoxysilane, vinyldimethylmethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-mercaptopropylmethyldimethoxysilane; silicone varnishes; and polysiloxanes. The use of a physical property modifier can increase the hardness of the cured product, or conversely, decrease the hardness of the cured product and increase the elongation at break. The physical property modifiers may be used alone or in combination of two or more.

[0131] In particular, compounds that hydrolyze to form a compound having a monovalent silanol group in the molecule have the effect of reducing the modulus of the cured product without increasing the stickiness of the surface of the cured product. Compounds that hydrolyze to form a compound having a monovalent silanol group in the molecule are particularly preferred, with compounds that form trimethylsilanol being particularly preferred. Examples of compounds that hydrolyze to form a compound having a monovalent silanol group in the molecule include the compounds described in JP-A-5-117521. Other examples include derivatives of alkyl alcohols such as hexanol, octanol, and decanol that hydrolyze to form trialkylsilanols such as trimethylsilanol, and derivatives of polyhydric alcohols with three or more hydroxyl groups such as trimethylolpropane, glycerin, pentaerythritol, and sorbitol that hydrolyze to form trialkylsilanols such as trimethylsilanol, as described in JP-A-11-241029. Examples include derivatives of oxyalkylene polymers that produce silicon compounds that produce trialkylsilanols such as trimethylsilanol upon hydrolysis, as described in JP-A-7-258534. Furthermore, polymers having crosslinkable hydrolyzable silicon-containing groups and silicon-containing groups that can be hydrolyzed to monosilanol-containing compounds, as described in JP-A-6-279693, can also be used. The physical property adjusting agent is used in an amount of 0.1 to 20 parts by weight, preferably 0.5 to 10 parts by weight, per 100 parts by weight of the total of the weight of the polyoxyalkylene polymer (A) and the weight of the (meth)acrylic polymer (D).

[0132] (tackifying resin) The paint-undercoat sealant may contain a tackifier resin for the purpose of increasing the adhesiveness and adhesion of the cured product to the substrate, etc. The tackifier resin is not particularly limited, and any tackifier resin commonly used in various curable compositions can be used. Specific examples of tackifying resins include terpene resins, aromatic modified terpene resins, hydrogenated terpene resins, terpene-phenol resins, phenol resins, modified phenol resins, xylene-phenol resins, cyclopentadiene-phenol resins, coumarone-indene resins, rosin resins, rosin ester resins, hydrogenated rosin ester resins, xylene resins, low-molecular-weight polystyrene resins, styrene copolymer resins, styrene block copolymers, hydrogenated styrene block copolymers, petroleum resins, hydrogenated petroleum resins, and DCPD resins. Examples of petroleum resins include C5 hydrocarbon resins, C9 hydrocarbon resins, and C5C9 hydrocarbon copolymer resins. These may be used alone or in combination of two or more. The amount of the tackifier resin used is preferably 2 to 100 parts by weight, more preferably 5 to 50 parts by weight, and even more preferably 5 to 30 parts by weight, per 100 parts by weight of the total weight of the polyoxyalkylene polymer (A) and the (meth)acrylic polymer (D). Using an amount of the tackifier resin within this range allows for the formation of a cured product with good adhesion and cohesion to the substrate. The paint-undercoat sealant has an appropriate viscosity and is easy to handle.

[0133] (Other compounds containing epoxy groups) The paint base sealant may contain other compounds containing epoxy groups in addition to the epoxy compound (B). The use of other compounds containing epoxy groups can improve the recovery of the cured product. Examples of other compounds containing epoxy groups include epoxidized unsaturated fats and oils, epoxidized unsaturated fatty acid esters, epichlorohydrin derivatives, and mixtures thereof. Specific examples of other compounds containing epoxy groups include epoxidized soybean oil, epoxidized linseed oil, bis(2-ethylhexyl)-4,5-epoxycyclohexane-1,2-dicarboxylate (E-PS), epoxy octyl stearate, and epoxy butyl stearate. The amount of the other epoxy group-containing compound used is preferably 0.5 to 50 parts by weight per 100 parts by weight of the total of the weight of the polyoxyalkylene polymer (A) and the weight of the (meth)acrylic polymer (D).

[0134] (Other epoxy resins) The paint-undercoat sealant may contain an epoxy resin other than the epoxy compound (B). The ratio of the total weight of the polyoxyalkylene polymer (A) and the (meth)acrylic polymer (D) to the weight of the other epoxy resin is preferably in the range of 100 / 1 to 1 / 100, expressed as (weight of polymer (A) and weight of polymer (C)) / (weight of epoxy resin). When the total weight of the polyoxyalkylene polymer (A) and the (meth)acrylic polymer (D) and the other epoxy resin are used in the above ratio, a high-strength cured product having excellent impact strength and toughness is easily formed. When other epoxy resins are used, the paint base sealant may contain a curing agent together with the other epoxy resins. The type of curing agent is not particularly limited, and commonly used curing agents can be used. The amount of the curing agent used is preferably 0.1 to 300 parts by weight per 100 parts by weight of the other epoxy resin.

[0135] (light curing substance) The paint base sealant may contain a photocurable substance. The use of a photocurable substance forms a film of the photocurable substance on the cured surface of the paint base sealant, improving the stickiness and weather resistance of the cured product. Various compounds such as organic monomers, oligomers, and resins are known as photocurable substances. Many compositions containing photocurable substances are also known. Representative photocurable substances include unsaturated acrylic compounds, polyvinyl cinnamates, and azido resins. Examples of unsaturated acrylic compounds include monomers, oligomers, and mixtures thereof having one or more acrylic unsaturated groups or methacrylic unsaturated groups. The amount of the photocurable substance used is preferably 0.1 to 20 parts by weight, more preferably 0.5 to 10 parts by weight, per 100 parts by weight of the total of the weight of the polyoxyalkylene polymer (A) and the weight of the (meth)acrylic polymer (D). When the amount of the photocurable substance used falls within this range, a flexible cured product that is excellent in weather resistance and inhibits the occurrence of cracks is likely to be formed.

[0136] (oxygen curing substance) The paint-undercoat sealant may contain an oxygen-curing substance. Examples of oxygen-curing substances include unsaturated compounds that can react with oxygen in the air. When the curable substance contains an oxygen-curing substance, the oxygen-curing substance reacts with oxygen in the air to form a cured film near the surface of the cured paint-undercoat sealant. The formation of a cured film on the surface of the cured product prevents stickiness and the adhesion of dirt and dust to the surface of the cured product. Specific examples of oxygen-curing substances include drying oils such as tung oil and linseed oil; various alkyd resins obtained by modifying drying oils; acrylic polymers modified with drying oils, epoxy resins other than the epoxy compound (B), and silicone resins; and liquid polymers such as 1,2-polybutadiene, 1,4-polybutadiene, or polymers of C5-C8 dienes obtained by polymerizing or copolymerizing diene compounds such as butadiene, chloroprene, isoprene, or 1,3-pentadiene. These may be used alone or in combination of two or more. The amount of oxygen-curable substance used is preferably 0.1 to 20 parts by weight, more preferably 0.5 to 10 parts by weight, per 100 parts by weight of the total weight of the polyoxyalkylene polymer (A) and the (meth)acrylic polymer (D). Using an amount of oxygen-curable substance within this range makes it easier to form a cured product whose surface is less susceptible to contamination by dirt and dust and has excellent mechanical properties such as tensile strength. As described in JP-A-3-160053, the oxygen-curable substance is preferably used in combination with a photocurable substance.

[0137] <Manufacturing method for paint base sealant> The paint base sealant material includes: a polyoxyalkylene polymer (A) having a reactive silicon group; an epoxy compound (B); and an aminosilane coupling agent (C) having a triethoxysilyl group, and the mixture is mixed to obtain a mixture; and mixing the aforementioned mixture with a curing catalyst (E). The epoxy compound (B) has an aromatic ring and / or a cycloalkane ring in its structure.

[0138] The polyoxyalkylene polymer (A) having a reactive silicon group, the epoxy compound (B), the aminosilane coupling agent (C) having a triethoxysilyl group, and the curing catalyst (E) are as described above. In addition, in the method for producing a sealant for paint substrate, various optional components other than the polyoxyalkylene polymer (A) having a reactive silicon group, the epoxy compound (B), the aminosilane coupling agent (C) having a triethoxysilyl group, and the curing catalyst (E) may be used. Such optional components are also as described above for the sealant for paint substrate.

[0139] The method for producing a sealant material for paint substrates includes mixing a polyoxyalkylene polymer (A) having a reactive silicon group, an epoxy compound (B), and an aminosilane coupling agent (C) having a triethoxysilyl group to obtain a mixture. The method for mixing a polyoxyalkylene polymer (A) having a reactive silicon group, an epoxy compound (B), and an aminosilane coupling agent (C) having a triethoxysilyl group to obtain a mixture is not particularly limited, as long as the curing reaction of the mixture does not proceed excessively. For example, a method may be used in which a premix of an epoxy compound (B) and an aminosilane coupling agent (C) having a triethoxysilyl group is mixed with a polyoxyalkylene polymer (A) having a reactive silicon group to obtain a mixture. Heating may be performed when premixing the epoxy compound (B) and the aminosilane coupling agent (C) having a triethoxysilyl group. The temperature during heating and mixing can be appropriately selected depending on the types of epoxy compound (B) and aminosilane coupling agent (C) having a triethoxysilyl group used.

[0140] The method for producing the paint-under sealant material includes mixing the above-mentioned mixture with a curing catalyst (E). The method for mixing the above mixture with the curing catalyst (E) is not particularly limited as long as the curing reaction of the paint-undercoat sealant does not proceed excessively.

[0141] The paint base sealant can be prepared as a one-component type in which all ingredients are mixed in advance, sealed, and stored, and then cured by moisture in the air after application.The paint base sealant can also be prepared as a two-component type in which a curing agent containing ingredients such as a curing catalyst and water is mixed with a separately prepared mixture containing a polyoxyalkylene polymer (A), an epoxy compound (B), and an aminosilane coupling agent (C) having a triethoxysilyl group before use.From the standpoint of workability, the one-component type is preferred. When a paint primer sealant is a one-component type, all ingredients are premixed, so it is preferable to dehydrate and dry the water-containing ingredients before use, or to dehydrate them under reduced pressure during blending. In addition to the dehydration and drying method, adding an alkoxysilane compound such as methyltrimethoxysilane, phenyltrimethoxysilane, n-propyltrimethoxysilane, vinyltrimethoxysilane, vinylmethyldimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropylmethyldiethoxysilane, or 3-glycidoxypropyltrimethoxysilane can further improve storage stability. Partially condensed silane compounds such as Evonik's Dynasylan 6490 can also be used as dehydrating agents from the standpoint of safety and stability. The amount of the dehydrating agent, particularly a silicon compound capable of reacting with water such as vinyltrimethoxysilane, used is preferably 0.1 to 20 parts by weight, more preferably 0.5 to 10 parts by weight, per 100 parts by weight of the total of the weight of the polyoxyalkylene polymer (A) and the weight of the (meth)acrylic polymer (D).

[0142] Paint-undercoat sealants can also be used as architectural sealants, industrial adhesives, waterproof coating film-forming compositions, pressure-sensitive adhesive raw materials, and the like. Paint-undercoat sealants can also be used as sealants for buildings, ships, automobiles, roads, and the like. Furthermore, paint-undercoat sealants can adhere to a wide range of substrates, including glass, porcelain, wood, metal, and resin moldings, either alone or with the aid of a primer. Therefore, paint-undercoat sealants can also be used in various types of sealing and adhesive compositions. In addition to conventional adhesives, paint-undercoat sealants can also be used as contact adhesives. Furthermore, paint-undercoat sealants are useful as food packaging materials, cast rubber materials, molding materials, and paints. The cured products of the above-mentioned paint-undercoat sealants exhibit low water absorption. Therefore, the above-mentioned paint-undercoat sealants and their cured products are particularly suitable for waterproof materials, such as sealants, waterproof adhesives, and waterproof coatings.

[0143] <Method for manufacturing a cured product of a sealant for use under paint> Prior to curing, the paint-underlayment sealant is formed into a desired shape by a method such as coating, casting, or filling.

[0144] The paint-under sealant material that has been applied, cast, or filled and shaped is cured under a desired environment, such as room temperature and normal humidity.

[0145] The cured product of the paint-undercoat sealant material thus formed exhibits good adhesion to paints, including oil-based paints such as weak solvent paints and strong solvent paints, and water-based paints. The cured product of the paint base sealant material thus formed exhibits good adhesion to a variety of adherends, including materials commonly used as building materials, such as rigid polyvinyl chloride resin, mortar, and concrete. [Example]

[0146] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0147] (Synthesis Example 1) Using polyoxypropylene glycol with a number-average molecular weight of approximately 4500 as an initiator, propylene oxide was polymerized with a zinc hexacyanocobaltate glyme complex catalyst to obtain polyoxypropylene (P-1) with a number-average molecular weight of 27,900 (17,700 molecular weight calculated as the terminal group) and a molecular weight distribution (Mw / Mn) of 1.21, bearing hydroxyl groups at both ends. Subsequently, 1.2 molar equivalents of sodium methoxide were added to the hydroxyl groups of the hydroxyl-terminated polyoxypropylene (P-1) as a 28% methanol solution. After removing the methanol by vacuum devolatilization, an additional 1.5 molar equivalents of allyl chloride was added to the hydroxyl groups of the polymer (P-1) to convert the terminal hydroxyl groups to allyl groups. Unreacted allyl chloride was then removed by vacuum devolatilization. The resulting crude polyoxypropylene was mixed with n-hexane and water, stirred, and the water was removed by centrifugation. The resulting hexane solution was then devolatilized under reduced pressure to remove metal salts from the polymer. This resulted in the production of polyoxypropylene (Q-1) having allyl groups at its termini. 500 g of this polymer (Q-1) was mixed with 50 μL of a platinum divinyldisiloxane complex solution (a 3 wt. % platinum equivalent isopropanol solution), and 4.8 g of dimethoxymethylsilane was slowly added dropwise while stirring. The resulting mixture was reacted at 100°C for 2 hours, after which the unreacted dimethoxymethylsilane was distilled off under reduced pressure to produce polyoxypropylene polymer (A-1) (hereinafter also referred to as polymer (A-1)) having terminal dimethoxymethylsilyl groups and a number-average molecular weight of approximately 28,500. Polymer (A-1) contained an average of 0.8 dimethoxymethylsilyl groups at each terminus, with an average of 1.6 per molecule.

[0148] (Synthesis Example 2) A mixture of 43 g of methyl methacrylate, 204 g of butyl acrylate, 45 g of stearyl methacrylate, 7.2 g of γ-methacryloxypropyldimethoxymethylsilane, and 13 g of IBA (180 g of isobutyl alcohol) heated to 105°C was added dropwise over 5 hours. A solution of 1.4 g of azobis-2-methylbutyronitrile as a polymerization initiator was then added dropwise over 1 hour. After 2 hours of post-polymerization, a (meth)acrylic acid ester copolymer (D-1) (hereinafter also referred to as polymer (D-1)) with a solids concentration of 60%, a number-average molecular weight of 17,800, and an average of 1.83 dimethoxymethylsilyl groups per molecule was obtained.

[0149] (Synthesis Example 3) Using polyoxypropylene glycol with a number-average molecular weight of approximately 4500 as an initiator, propylene oxide was polymerized with a zinc hexacyanocobaltate glyme complex catalyst to obtain polyoxypropylene (P-2) with a number-average molecular weight of 14,300 (9,100 molecular weight calculated as end groups) and a molecular weight distribution (Mw / Mn) of 1.21, bearing hydroxyl groups at both ends. To the resulting hydroxyl-terminated polyoxypropylene (P-2), 1.2 molar equivalents of sodium methoxide were added as a 28% methanol solution. After removing the methanol by vacuum devolatilization, an additional 1.5 molar equivalents of allyl chloride was added to the hydroxyl groups of the polymer (P-2) to convert the terminal hydroxyl groups to allyl groups. Unreacted allyl chloride was removed by vacuum devolatilization. The resulting unpurified polyoxypropylene was mixed with n-hexane and water, stirred, and then centrifuged to remove the water. The resulting hexane solution was then devolatilized under reduced pressure to remove metal salts from the polymer. This resulted in the production of polyoxypropylene (Q-2) having allyl groups at its terminals. 50 μL of platinum divinyldisiloxane complex solution (3 wt. % platinum equivalent isopropanol solution) was added to 500 g of this polymer (Q-2), and 8.4 g of dimethoxymethylsilane was slowly added dropwise while stirring. After reacting for 2 hours at 100°C, unreacted dimethoxymethylsilane was distilled off under reduced pressure to produce polyoxypropylene polymer (A-2) (hereinafter also referred to as polymer (A-2)) with a number-average molecular weight of 14,600 and dimethoxymethylsilyl groups at its terminals. Polymer (A-2) contains an average of 0.8 dimethoxymethylsilyl groups at each terminal, with an average of 1.5 per molecule.

[0150] Example 1 Two parts by weight of bisphenol A type epoxy resin (manufactured by Mitsubishi Chemical Corporation, trade name: jER (registered trademark) 828), 2.58 parts by weight of 3-aminopropyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KBE-903), and 5 parts by weight of tricresyl phosphate (manufactured by Daihachi Chemical Industry Co., Ltd., trade name: TCP) were mixed at 80°C for one hour to obtain mixture (1). Mixture (1), 100 parts by weight of the polymer (A-1) obtained in Synthesis Example 1, 3 parts by weight of vinyltrimethoxysilane (manufactured by Momentive Performance Materials Japan, LLC, trade name: SILQUEST A-171 SILAN), and 3 parts by weight of 3-(2-aminoethylamino)propylmethyldimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KBM-602) were mixed together to obtain mixture (2). Next, the mixture (2) was mixed with 2 parts by weight of dibutyltin diacetylacetonate (manufactured by Nitto Kasei Co., Ltd., trade name: Neostan U220H) to obtain a sealant material for paint undercoat.

[0151] (tensile properties) The resulting paint primer sealant was filled into a mold and cured for 7 days at 23°C and 55% relative humidity to produce a sheet-like cured product approximately 3 mm thick. The resulting cured product was punched into a No. 3 dumbbell shape according to JIS K 6251 to obtain test specimens. Tensile tests (maximum load = 5 N, tensile speed 200 mm / min) were performed on the resulting test specimens using an autograph (product name: AGS-J, manufactured by Shimadzu Corporation) at 23°C and 50% relative humidity. The measurement results for 100% modulus (M100), breaking strength (Tb), and breaking elongation (Eb) are shown in Table 1.

[0152] (paint adhesion) A paint was applied to the surface of the cured product. A weak solvent paint (manufactured by Nippon Paint Co., Ltd., product name: Fine Silicon Fresh II) and a water-based paint (manufactured by Nippon Paint Co., Ltd., product name: Power Ode Fresh Si) were used as the paints. The cured product to which the paint was applied was dried at 23°C for 7 days to obtain a paint adhesion test specimen. A paint adhesion test was performed on the paint adhesion test specimen using Cellotape (registered trademark) at 23°C and 50% relative humidity according to the cross-cut method of JIS K 5600. Specifically, an incision was made in the paint adhesion test specimen, and Cellotape (registered trademark) was attached over the incision. The Cellotape (registered trademark) was then peeled off. The condition of the coating on the paint adhesion test specimen after peeling off the Cellotape (registered trademark) was evaluated according to the following evaluation criteria. The evaluation results are shown in Table 1. A: On the test pieces for the paint adhesion test, neither the weak solvent paint film nor the water-based paint film peeled off. B: In the paint adhesion test specimen, the weak solvent paint film has not peeled off, but the water-based paint film has partially peeled off. C: On the test piece for the paint adhesion test, the weak solvent paint film is partially peeled off, but the water-based paint is not peeled off. D: On the paint adhesion test specimen, both the weak solvent paint film and the water-based paint film have partially peeled off.

[0153] Example 2 A paint-undercoat sealant was obtained in the same manner as in Example 1, except that the polymer (A-1) was changed to the polymer (A-2) obtained in Synthesis Example 3.

[0154] Example 3 Polymer (D-1) obtained in Synthesis Example 2 was uniformly mixed with 70 parts by weight of polymer (A-1) obtained in Synthesis Example 1 so that the solid content was 30 parts by weight, and then IBA was distilled off using a rotary evaporator to obtain a mixture of 70 parts by weight of polymer (A-1) and 30 parts by weight of polymer (D-1). A paint-undercoat sealant was obtained in the same manner as in Example 1, except that the polymer (A-1) was changed to a mixture of 70 parts by weight of polymer (A-1) and 30 parts by weight of polymer (D-1).

[0155] Example 4 A sealant material for paint undercoat was obtained in the same manner as in Example 3, except that tricresyl phosphate was changed to alkylsulfonic acid phenyl ester (manufactured by Lanxess KK, trade name: Mesamoll (registered trademark)).

[0156] Example 5 Each component of the mixture (1) and 2 parts by weight of tris[3-(trimethoxysilyl)propyl] isocyanurate (manufactured by Tokyo Chemical Industry Co., Ltd.) were mixed at 80° C. for 1 hour to obtain a mixture (1a). A paint-undercoat sealant was obtained in the same manner as in Example 3, except that the mixture (1) was replaced with the mixture (1a).

[0157] Example 6 A sealant material for paint undercoat was obtained in the same manner as in Example 3, except that tricresyl phosphate was changed to diisodecyl phthalate (DIDP, manufactured by Tokyo Chemical Industry Co., Ltd.).

[0158] Example 7 A paint-undercoat sealant was obtained in the same manner as in Example 6, except that the bisphenol A epoxy resin (jER (registered trademark) 828) was replaced with hydrogenated bisphenol A diglycidyl ether (manufactured by Kyoeisha Chemical Co., Ltd., trade name: Epolite 4000) and the content of each component was changed to the content shown in Table 2. The content of each component in Tables 1 to 4 is shown in parts by weight.

[0159] Example 8 A sealant material for paint undercoat was obtained in the same manner as in Example 3, except that tricresyl phosphate was changed to PPG3000 (manufactured by Mitsui Fine Chemicals, Inc., trade name: Actocol P-23K).

[0160] Example 9 A paint-undercoat sealant was obtained in the same manner as in Example 8, except that the bisphenol A epoxy resin (jER (registered trademark) 828) was replaced with hydrogenated bisphenol A diglycidyl ether (Epolite 4000) and the content of each component was changed to the content shown in Table 2.

[0161] Example 10 A sealant material for paint undercoat was obtained in the same manner as in Example 3, except that mixture (1) was changed to 2 parts by weight of bisphenol A type epoxy resin (jER (registered trademark) 828) and 2.58 parts by weight of 3-aminopropyltriethoxysilane (KBE-903).

[0162] Example 11 A paint-undercoat sealant was obtained in the same manner as in Example 10, except that the bisphenol A epoxy resin (jER (registered trademark) 828) was replaced with hydrogenated bisphenol A diglycidyl ether (Epolite 4000) and the content of each component was changed to the content shown in Table 3.

[0163] (Comparative Example 1) A paint-underlay sealant was obtained in the same manner as in Example 1, except that the mixture (1) was not used.

[0164] (Comparative Example 2) A paint-undercoat sealant material was obtained in the same manner as in Example 1, except that mixture (1) was changed to 2 parts by weight of bisphenol A-type epoxy resin (jER (registered trademark) 828), 3-(2-aminoethylamino)propylmethyldimethoxysilane (KBM-602) was changed to 3-(2-aminoethylamino)propyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., product name: KBM-603), and the content of each component was changed to the content shown in Table 3.

[0165] (Comparative Example 3) A paint-undercoat sealant was obtained in the same manner as in Comparative Example 2, except that the bisphenol A epoxy resin (jER (registered trademark) 828) was replaced with hydrogenated bisphenol A diglycidyl ether (Epolite 4000).

[0166] Comparative Example 4 A paint-undercoat sealant was obtained in the same manner as in Comparative Example 1, except that the polymer (A-1) was changed to a mixture of 70 parts by weight of polymer (A-1) and 30 parts by weight of polymer (D-1).

[0167] (Comparative Example 5) A paint-undercoat sealant was obtained in the same manner as in Example 3, except that mixture (1) was changed to 2 parts by weight of tris[3-(trimethoxysilyl)propyl] isocyanurate (manufactured by Tokyo Chemical Industry Co., Ltd.).

[0168] (Comparative Example 6) A paint-undercoat sealant was obtained in the same manner as in Comparative Example 2, except that the polymer (A-1) was changed to a mixture of 70 parts by weight of polymer (A-1) and 30 parts by weight of polymer (D-1).

[0169] (Comparative Example 7) A paint-undercoat sealant was obtained in the same manner as in Comparative Example 3, except that polymer (A-1) was changed to a mixture of 70 parts by weight of polymer (A-1) and 30 parts by weight of polymer (D-1), and the content of each component was changed to the content shown in Table 4.

[0170] The cured products of the sealant materials for use under paint of Examples 2 to 11 and Comparative Examples 1 to 7 were subjected to tensile tests and paint adhesion tests in the same manner as in Example 1. The results are shown in Tables 1 to 4.

[0171] [Table 1]

[0172] [Table 2]

[0173] [Table 3]

[0174] [Table 4]

[0175] Tables 1 to 3 show that the cured products of the paint base sealant materials of Examples 1 to 11, which contain a polyoxyalkylene polymer (A) having a reactive silicon group, an epoxy compound (B), and an aminosilane coupling agent (C) having a triethoxysilyl group, either have good adhesion to both weak solvent paint coating films and water-based paint coating films, or have good adhesion to either weak solvent paint coating films or water-based paint coating films. In contrast, Tables 3 and 4 show that the cured products of the paint-undercoat sealant materials of Comparative Examples 1 to 7, which do not contain the epoxy compound (B) and / or the aminosilane coupling agent (C) having a triethoxysilyl group, have poor adhesion to both weak-solvent paint coatings and water-based paint coatings.

Claims

1. The composition comprises a polyoxyalkylene polymer (A) having a reactive silicon group, an epoxy compound (B), and an aminosilane coupling agent (C) having a triethoxysilyl group, The sealant material for use under paint, wherein the epoxy compound (B) has an aromatic ring and / or a cycloalkane ring in its structure.

2. The reactive silicon group is represented by the following formula (1): -SiR １ (OCH) ３ ) ２ (1) (In formula (1), R １ is a substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms, or R ０ ３ represents a triorganosiloxy group represented by SiO—, and three R ０ are hydrocarbon groups having 1 to 20 carbon atoms, and they may be the same or different. The paint-undercoat sealant material according to claim 1, wherein the formula is:

3. 3. The paint-undercoat sealant according to claim 1, which comprises a (meth)acrylic polymer (D) having a reactive silicon group.

4. a polyoxyalkylene polymer (A) having a reactive silicon group, an epoxy compound (B), and an aminosilane coupling agent (C) having a triethoxysilyl group to obtain a mixture; mixing the mixture with a curing catalyst (E), The method for producing a sealant material for use under paint, wherein the epoxy compound (B) has an aromatic ring and / or a cycloalkane ring in its structure.

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