A curable composition, an adhesive composition, and a method for producing the curable composition.

Abstract

To provide a curable composition that has low viscosity and high workability, is quickly curable, and also excels in the mechanical properties of its cured product, adhesiveness to a substrate, and heat resistance, and provide an adhesive composition.SOLUTION: A curable composition has a (meth)acrylic polymer (A) having crosslinkable silyl groups, and an oxyalkylene polymer (B) having crosslinkable silyl group, wherein the (meth)acrylic polymer (A) has 1.5-3.0 crosslinkable silyl groups in one molecule, and the polymer has a viscosity at 25°C of 1,000-7,000 mPa s.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a curable composition and its use as an adhesive composition. More specifically, the present invention relates to a curable composition that can be cured by moisture in the atmosphere or the like to form a cured product that exhibits excellent elasticity and also has excellent heat resistance, an adhesive composition containing the curable composition, and a method for producing the curable composition. [Background technology]

[0002] Elastic adhesives are adhesives that have rubber elasticity when cured, and absorb and relieve internal and external stresses on the adhesive joint, making them less susceptible to stress concentration at the adhesive interface, resistant to volumetric shrinkage distortion and impact after curing, and less susceptible to temperature changes, etc. For these reasons, they are widely used in construction-related applications, electrical and electronic applications, automotive applications, medical equipment applications, etc. As elastic adhesives, compositions containing various polymers such as silicone-based, modified silicone-based, urethane-based, and polysulfide-based polymers having room temperature curable crosslinkable groups are generally known. Modified silicone polymers are curable compositions based on oxyalkylene polymers having hydrolyzable silyl groups. When applied at construction sites, the curing rate is relatively slow, allowing for fine adjustments even after application. They are also weather-resistant and have a good balance of mechanical properties such as breaking elongation and breaking strength. For these reasons, they are used alone or in combination with epoxy compounds as the base polymer for elastic adhesives, or in combination with silyl-group-containing (meth)acrylic acid ester polymers as the base polymer for highly weather-resistant adhesives. For example, Patent Documents 1 and 2 disclose examples in which modified silicone polymers are used alone or in combination with epoxy compounds for elastic adhesive applications. Patent Document 3 discloses that an alkoxysilyl group-modified polyoxyalkylene and an alkoxysilyl group-containing (meth)acrylic acid ester polymer are used as the base polymer of an elastic adhesive for tile application.

[0003] On the other hand, elastic adhesives based on modified silicone polymers bond a wide range of materials, including various metals, plastics, ceramics, and rubber, and are therefore used not only for bonding similar materials together, but also for bonding metals to dissimilar materials, and for bonding ceramic siding materials, ALC, concrete, and other materials used in construction and civil engineering. These applications do not necessarily require high weather resistance, and they are often used on factory production lines. For example, they are used to bond electronic components such as capacitors and coils to circuit boards on electronic component production lines, and to bond polyurethane and polypropylene automotive interior materials on automobile production lines. Patent Document 4 discloses an example of an industrial use of a modified silicone adhesive. In addition, siding boards and ALC panel components may be manufactured in advance at a factory, with the remaining assembly work carried out at the construction site, in which case the gluing work is carried out on the factory's production line. Patent Document 5 discloses a curable composition containing, as its main components, a silyl group-containing polyalkylene oxide and a silyl group-containing (meth)acrylic acid ester polymer as an elastic adhesive used in factories to bond interior wall materials such as decorative plywood and vinyl cloth to interior wall base materials such as gypsum board and slate board. When an elastic adhesive containing a modified silicone polymer as a base polymer is used on a factory line, the curable composition should have as low a viscosity as possible and should have a fast curing rate in order to improve workability. Patent Documents 6 and 7 disclose curable compositions containing a (meth)acrylic acid ester polymer having a hydrolyzable silyl group and a hydrolyzable silyl group-containing oxyalkylene polymer. However, when elastic adhesives using the curable compositions disclosed in these patent publications are used on factory lines, silyl group-containing (meth)acrylic acid ester polymers with low weight-average molecular weights have few silyl groups per molecule, resulting in slow curing speeds and poor adhesive properties. On the other hand, while high weight-average molecular weights increase the number of silyl groups per molecule, they are difficult to use due to excessively high viscosity. Furthermore, due to recent climate change, typified by global warming, the temperature environment in which adhesives are used has tended to rise, and there has been a demand for curable compositions with higher heat resistance. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 57-182350 [Patent Document 2] Japanese Patent Application Publication No. 61-247723 [Patent Document 3] Japanese Patent Application Laid-Open No. 2010-185078 [Patent Document 4] Japanese Patent Application Laid-Open No. 2000-290632 [Patent Document 5] Japanese Patent Application Laid-Open No. 2008-121408 [Patent Document 6] International Publication No. 2008 / 059872 [Patent Document 7] Japanese Patent Application Laid-Open No. 2014-118502 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made in view of the above circumstances, and provides a curable composition that has low viscosity and a fast curing rate when used in a factory line, and therefore has excellent workability, and the cured product also has excellent adhesive strength, mechanical properties, and heat resistance; and an elastic adhesive composition containing the curable composition. In this invention, a factory production line or factory line includes not only a line production method using a belt conveyor or the like, but also a batch production method, continuous production method, process production method, individual production method, etc., in which carts or the like are transported from one process to the next using human power or transportation equipment such as rails. [Means for solving the problem]

[0006] As a result of intensive research aimed at solving the above-mentioned problems, the present inventors have found that a curable composition containing a (meth)acrylic polymer having a specific crosslinkable silyl group and an oxyalkylene polymer having a crosslinkable silyl group, wherein the (meth)acrylic polymer has a specific amount of crosslinkable silyl groups, not only improves the heat resistance of a cured product and an adhesive containing the cured product, but also has low viscosity and a fast curing rate. The present invention was completed based on this finding. The present invention provides the following means.

[0007] [1] A curable composition comprising a (meth)acrylic polymer (A) having a crosslinkable silyl group and an oxyalkylene polymer (B) having a crosslinkable silyl group, The (meth)acrylic polymer (A) has 1.5 to 3.0 crosslinkable silyl groups per molecule and has a viscosity at 25°C of 1,000 mPa·s to 7,000 mPa·s. [2] The curable composition according to [1], wherein the (meth)acrylic polymer (A) has a number average molecular weight (Mn) of 2,000 to 6,000, and a ratio of Mw to the weight average molecular weight (Mw), Mw / Mn, of 1.5 to 2.7. [3] The curable composition according to [1] or [2], wherein the (meth)acrylic polymer (A) contains 70 to 98 mass% of (meth)acrylic monomer units and 2 to 30 mass% of monomer units having a crosslinkable silyl group, based on all monomer units constituting the (meth)acrylic polymer, and the amount of a (meth)acrylic acid alkyl ester monomer having an alkyl group having 4 or more carbon atoms is 60 to 100 parts by mass, relative to 100 parts by mass of the (meth)acrylic monomer units contained in the (meth)acrylic polymer (A). [4] The curable composition according to [3], wherein, among the (meth)acrylic acid alkyl ester monomers having an alkyl group of 4 or more carbon atoms constituting the (meth)acrylic polymer (A), a (meth)acrylic acid alkyl ester monomer unit having an alkyl group of 10 or more carbon atoms is 4 to 40 parts by mass relative to 100 parts by mass of all the (meth)acrylic monomers. [5] The curable composition according to any one of [1] to [4], wherein the monomer having a crosslinkable silyl group that constitutes the (meth)acrylic polymer (A) is a silyl group-containing (meth)acrylic acid ester. [6] The curable composition according to any one of [1] to [5], wherein the (meth)acrylic polymer (A) has double bonds in an amount of 0.01 meq / g to 1.0 meq / g. [7] The curable composition according to any one of [1] to [6], wherein the oxyalkylene polymer (B) has a number average molecular weight (Mn) of 5,000 to 60,000. [8] The curable composition according to any one of [1] to [7], wherein the amounts of the (meth)acrylic polymer (A) and the oxyalkylene polymer (B) used are 10 to 90 / 90 to 10 in mass ratio. [9] The curable composition according to any one of [1] to [8], which contains, as a curing accelerator, one or more compounds selected from the group consisting of tin-based catalysts, titanium-based catalysts, and tertiary amines.

[10] An adhesive composition comprising the curable composition according to any one of [1] to [9].

[11] The method for producing a curable composition according to any one of [1] to [9], wherein the (meth)acrylic polymer (A) is produced by a high-temperature continuous polymerization method. [Effects of the Invention]

[0008] The curable composition of the present invention has low viscosity and excellent workability. Furthermore, when this composition is used, a cured product having excellent strength, elongation, adhesiveness, and heat resistance can be obtained. For these reasons, it is suitable for use as an elastic adhesive in a factory line. DETAILED DESCRIPTION OF THE INVENTION

[0009] The present invention will be described in detail below. In this specification, "(meth)acrylic" means acrylic and / or methacrylic, "(meth)acrylate" means acrylate and / or methacrylate, and "(meth)acryloyl group" means acryloyl group and / or methacryloyl group.

[0010] The curable composition of the present invention contains, as essential components, a (meth)acrylic polymer having a crosslinkable silyl group as component (A) and an oxyalkylene polymer having a crosslinkable silyl group as component (B). Each component will be described in detail below.

[0011] <Component (A): (Meth)acrylic polymer having a crosslinkable silyl group> The (meth)acrylic polymer having a crosslinkable silyl group is a polymer having a structural unit derived from a (meth)acrylic monomer, and can be obtained, for example, by polymerizing a monomer mixture containing a (meth)acrylic monomer. The (meth)acrylic monomer is a monomer having a (meth)acryloyl group in the molecule, and examples thereof include (meth)acrylic acid, (meth)acrylic acid alkyl esters, and (meth)acrylic acid alkoxyalkyl esters. The amount of the (meth)acrylic monomer used is preferably 70 to 98 mass %, more preferably 75 to 95 mass %, assuming that the total amount of all monomers in the polymer is 100 mass %.

[0012] Specific examples of the (meth)acrylic acid alkyl ester include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, cyclohexyl (meth)acrylate, methylcyclohexyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. Xyl, n-nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, stearyl (meth)acrylate, nonadecyl (meth)acrylate, eicosyl (meth)acrylate, heneicosyl (meth)acrylate, behenyl (meth)acrylate, tetracosyl (meth)acrylate, (meth) Hexacosyl acrylate, octacosyl (meth)acrylate, triacontyl (meth)acrylate, dotriacontyl (meth)acrylate, tetratriacontyl (meth)acrylate, hexatriacontyl (meth)acrylate, octatriacontyl (meth)acrylate, tetracontyl (meth)acrylate, isodecyl (meth)acrylate, isoundecyl (meth)acrylate, isolauryl (meth)acrylate, isotridecyl (meth)acrylate, isotetradecyl (meth)acrylate, isopentadecyl (meth)acrylate, (meth)acrylic isohexadecyl (meth)acrylate, isoheptadecyl (meth)acrylate, isostearyl (meth)acrylate, isononadecyl (meth)acrylate, isoeicosyl (meth)acrylate, isoheneicosyl (meth)acrylate, isobehenyl (meth)acrylate, isotetracosyl (meth)acrylate, isohexacosyl (meth)acrylate, isooctacosyl (meth)acrylate, isotriacontyl (meth)acrylate, isodotriacontyl (meth)acrylate, isotetratriacontyl (meth)acrylate, isohexatriacontyl (meth)acrylate,Examples include alkyl (meth)acrylate esters having a linear or branched aliphatic alkyl group or an alicyclic alkyl group, such as isooctatriacontyl (meth)acrylate and isotetracontyl (meth)acrylate, and one or more of these can be used. Among these, (meth)acrylic acid alkyl ester monomers having an alkyl group having 4 or more carbon atoms are preferred because the resulting (meth)acrylic polymer has excellent compatibility with the oxyalkylene polymer having a crosslinkable silyl group, which is component (B), has low viscosity, and is also excellent in heat resistance. Among the (meth)acrylic monomers, the amount of (meth)acrylic acid alkyl ester having an alkyl group having 4 or more carbon atoms used is preferably 60 to 100 parts by mass, and more preferably 80 to 100 parts by mass, based on 100 parts by mass of all the (meth)acrylic monomers.

[0013] Furthermore, it is more preferable to use a (meth)acrylic acid alkyl ester having an alkyl group having 10 or more carbon atoms as part of the (meth)acrylic monomer, since this ensures better compatibility with the oxyalkylene polymer (B) and improves mechanical properties and heat resistance. The number of carbon atoms in the alkyl group is preferably 10 to 20, more preferably 12 to 18, and even more preferably 14 to 16. The amount of (meth)acrylic acid alkyl ester having an alkyl group having 10 or more carbon atoms used is preferably 4 to 40 parts by mass, more preferably 10 to 30 parts by mass, per 100 parts by mass of all (meth)acrylic monomers constituting the (meth)acrylic polymer. When an alkyl (meth)acrylate ester having an alkyl group having 10 or more carbon atoms is used in the (meth)acrylic polymer (A), the remaining monomer among the alkyl (meth)acrylate esters having an alkyl group having 4 to 9 carbon atoms is used. In this case, the amount of the alkyl (meth)acrylate ester having an alkyl group having 4 to 9 carbon atoms used is 20 to 96 parts by mass per 100 parts by mass of all the (meth)acrylic monomers.

[0014] Among the above (meth)acrylic monomers, preferred (meth)acrylic acid alkyl esters having an alkyl group having 4 or more carbon atoms are n-butyl (meth)acrylate, isobutyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, and tetradecyl (meth)acrylate, in view of ease of availability and ease of handling.

[0015] The (meth)acrylic polymer (A) of the present invention can be copolymerized with a (meth)acrylic acid alkyl ester, a (meth)acrylic acid alkoxyalkyl ester, or other monomers having an alkyl group having 1 to 3 carbon atoms, in an amount not exceeding 20% ​​by mass.

[0016] Specific examples of (meth)acrylic acid alkoxyalkyl esters include methoxymethyl (meth)acrylate, methoxyethyl (meth)acrylate, methoxybutyl (meth)acrylate, methoxyhexyl (meth)acrylate, ethoxymethyl (meth)acrylate, ethoxyethyl (meth)acrylate, ethoxybutyl (meth)acrylate, ethoxyhexyl (meth)acrylate, butoxymethyl (meth)acrylate, butoxyethyl (meth)acrylate, butoxybutyl (meth)acrylate, and butoxyhexyl (meth)acrylate, and one or more of these can be used. Among these, from the viewpoint of the mechanical properties of the cured product, (meth)acrylic acid alkoxyalkyl esters having an alkoxyalkyl group having 2 to 8 carbon atoms are preferred, and (meth)acrylic acid alkoxyalkyl esters having an alkoxyalkyl group having 2 to 4 carbon atoms are more preferred.

[0017] The (meth)acrylic polymer contains a monomer unit having a crosslinkable silyl group in the molecule. The type of the crosslinkable silyl group is not particularly limited, and examples thereof include an alkoxysilyl group, a halogenosilyl group, and a silanol group. However, an alkoxysilyl group is preferred because it is easy to control the crosslinkability. Specific examples of the alkoxysilyl group include trialkoxysilyl groups such as trimethoxysilyl group, triethoxysilyl group, dimethoxyethoxysilyl group, and methoxydiethoxysilyl group; dialkoxysilyl groups such as methyldimethoxysilyl group, methyldiethoxysilyl group, ethyldimethoxysilyl group, and ethyldiethoxysilyl group; and monoalkoxysilyl groups such as dimethylmethoxysilyl group, dimethylethoxysilyl group, diethylmethoxysilyl group, and diethylethoxysilyl group. Among these, dialkoxysilyl groups and trialkoxysilyl groups are preferred in that the cured product exhibits good elongation and excellent heat resistance.

[0018] The average number of crosslinkable silyl groups contained in one molecule of the (meth)acrylic polymer (A) is 1.5 to 3.0 from the viewpoint of adhesive strength and heat resistance of the cured product. It is more preferably 1.7 to 2.8, and even more preferably 1.8 to 2.3. If the number is less than 1.5, the curing speed becomes too slow, reducing the productivity of the factory line. If the number exceeds 3.0, the curing speed becomes too fast, shortening the usable time and reducing workability. The position of the crosslinkable silyl group contained in the (meth)acrylic polymer is not particularly limited, and it may be located in a side chain and / or at the end of the polymer.

[0019] The crosslinkable silyl group can be obtained by copolymerizing a monomer mixture containing a (meth)acrylic monomer and a vinyl monomer having a crosslinkable silyl group. Examples of vinyl monomers having a crosslinkable silyl group include vinyl silanes such as vinyltrimethoxysilane, vinyltriethoxysilane, vinylmethyldimethoxysilane, and vinyldimethylmethoxysilane; (meth)acrylic acid alkoxysilyl alkyl esters such as trimethoxysilylpropyl (meth)acrylate, triethoxysilylpropyl (meth)acrylate, dimethylmethoxysilylpropyl (meth)acrylate, and methyldimethoxysilylpropyl (meth)acrylate; silyl group-containing vinyl ethers such as trimethoxysilylpropyl vinyl ether; and silyl group-containing vinyl esters such as vinyl trimethoxysilylundecanoate, and one or more of these may be used. From the viewpoint of ease of copolymerization between (meth)acrylic monomers, (meth)acrylic acid alkoxysilyl alkyl esters are preferred, and it is preferable to use one or more of trimethoxysilylpropyl (meth)acrylate, triethoxysilylpropyl (meth)acrylate, dimethylmethoxysilylpropyl (meth)acrylate, methyldimethoxysilylpropyl (meth)acrylate, and methyldiethoxysilylpropyl (meth)acrylate. The content of such a monomer containing a crosslinkable silyl group in the (meth)acrylic polymer (A) is preferably 2 to 30 mass %, more preferably 5 to 25 mass %, from the viewpoint of improving curability while maintaining low viscosity.

[0020] The (meth)acrylic polymer may be copolymerized with other monomers copolymerizable with the above-mentioned monomers. Examples of the other monomers include functional group-containing monomers such as 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, glycidyl (meth)acrylate, 2-aminoethyl (meth)acrylate, and ethylene oxide adducts of (meth)acrylic acid; (meth)acrylic acid aromatic esters such as phenyl (meth)acrylate, toluyl (meth)acrylate, and benzyl (meth)acrylate; fluorine-containing (meth)acrylic acid esters such as trifluoromethylmethyl (meth)acrylate, 2-trifluoromethylethyl (meth)acrylate, 2-perfluoroethylethyl (meth)acrylate, 2-perfluoroethyl-2-perfluorobutylethyl (meth)acrylate, 2-perfluoroethylmethyl (meth)acrylate, perfluoromethylmethyl (meth)acrylate, diperfluoromethylmethyl (meth)acrylate, 2-perfluoromethyl-2-perfluoroethylmethyl (meth)acrylate, 2-perfluorohexylethyl (meth)acrylate, 2-perfluorodecylethyl (meth)acrylate, and 2-perfluorohexadecylethyl (meth)acrylate; fluorine-containing olefins such as perfluoroethylene, perfluoropropylene, and vinylidene fluoride; Aromatic monomers such as styrene, vinyltoluene, α-methylstyrene, chlorostyrene, styrenesulfonic acid and its salts; Maleic anhydride; unsaturated dicarboxylic acids such as maleic acid and fumaric acid, and their mono- and di-alkyl esters; maleimide compounds such as maleimide, methylmaleimide, ethylmaleimide, propylmaleimide, butylmaleimide, hexylmaleimide, octylmaleimide, phenylmaleimide, and cyclohexylmaleimide; nitrile group-containing vinyl monomers such as acrylonitrile and methacrylonitrile; Amide group-containing vinyl monomers such as acrylamide and methacrylamide; vinyl esters such as vinyl acetate, vinyl propionate, vinyl pivalate, vinyl benzoate, and vinyl cinnamate; Alkenes such as ethylene and propylene; conjugated dienes such as butadiene and isoprene; Examples include, but are not limited to, vinyl chloride, vinylidene chloride, allyl chloride, allyl alcohol, etc. One or more of these may be used. When such a monomer is used, it is preferably used in an amount of less than 20% by mass, with the total monomer units of the (meth)acrylic polymer (A) being 100% by mass.

[0021] The number average molecular weight (Mn) of the (meth)acrylic polymer is a polystyrene-equivalent molecular weight determined by gel permeation chromatography (hereinafter referred to as "GPC"), and is preferably 1,000 to 7,000, more preferably 1,500 to 6,000, and even more preferably 2,000 to 5,000, from the viewpoints of workability, curability, and the mechanical strength and heat resistance of the cured product.

[0022] The molecular weight distribution of a (meth)acrylic polymer is calculated as the value (Mw / Mn) obtained by dividing the weight-average molecular weight (Mw) by the number-average molecular weight (Mn). From the viewpoint of balancing tensile properties and workability, Mw / Mn is preferably 4.0 or less, more preferably 3.0 or less, and even more preferably 2.5 or less. The lower limit of Mw / Mn is usually 1.0, preferably 1.2, and even more preferably 1.5. When Mw / Mn is large, the low-molecular-weight polymer chains in the (meth)acrylic polymer have higher molecular mobility than the high-molecular-weight polymer chains, increasing the probability of reaction with crosslinkable silyl groups, and the low-molecular-weight polymer chains react preferentially with the high-molecular-weight polymer chains. This results in the formation of microgels with high crosslink densities formed from low-molecular-weight polymer chains and microgels with high crosslink densities formed from high-molecular-weight polymer chains, resulting in the formation of a non-uniform crosslinked structure. On the other hand, when Mw / Mn is small, a more uniform crosslinked structure is formed, resulting in smaller differences in crosslink density within the cured composition and higher fracture toughness.

[0023] For the (meth)acrylic polymer of the present invention, the balance between the number of crosslinkable silyl groups per molecule and the average molecular weight is important. That is, if the average molecular weight per crosslinkable silyl group is too high, curing will be slow and the distance between crosslinking points will be too large, resulting in reduced adhesive strength. Conversely, if it is too small, the crosslinking density will be too high and the adhesive will be hard. The number-average molecular weight per crosslinkable silyl group is preferably 800 to 3,000, more preferably 1,000 to 2,500. Furthermore, the weight-average molecular weight per crosslinkable silyl group is preferably 1,500 to 6,500, more preferably 2,000 to 5,000.

[0024] The viscosity of the (meth)acrylic polymer is 1,000 to 7,000 mPa·s at 25° C., preferably 1,500 to 6,500 mPa·s, and more preferably 2,000 to 5,500 mPa·s. If the viscosity of the (meth)acrylic polymer exceeds 7,000 mPa·s, the viscosity of the curable composition increases, resulting in reduced workability. In order to keep the viscosity within the optimum range, it is necessary to control the molecular weight and to specify the monomer units of the polymer. For this purpose, it is preferable to use a (meth)acrylic acid ester having an alkyl group with 4 or more carbon atoms and copolymerize it with a (meth)acrylic acid ester having an alkyl group with 10 or more carbon atoms in a specific ratio.

[0025] In the present invention, the (meth)acrylic polymer preferably has a double bond in the molecule. When the (meth)acrylic polymer has an appropriate amount of double bonds, for example, even after the crosslinkable silyl group has cured, the double bonds react with oxygen to moderately increase the molecular weight, which is expected to improve adhesive strength and heat resistance. In addition, the double bonds are expected to react with aminosilane added as an adhesion promoter, further improving adhesiveness. Furthermore, it is expected that the adhesive will have the effect of mitigating contamination from the external environment when the adhesive has cured while protruding, and contamination due to bleeding of uncured components from the inside, etc.

[0026] The amount of double bonds contained in the (meth)acrylic polymer is preferably 0.01 meq / g or more from the viewpoint of exhibiting the above-mentioned properties, particularly the effect of improving stain resistance. On the other hand, if the amount of double bonds is too large, the degree of crosslinking of the cured product becomes too high, resulting in insufficient flexibility, and as a result, internal stress tends to increase and distortion tends to occur. In order to suppress a decrease in flexibility of the cured product due to excessive crosslinking reaction, the amount of double bonds is 0.01 to 1.0 meq / g, preferably 0.05 to 0.70 meq / g, and more preferably 0.1 to 0.50 meq / g. By setting the amount of double bonds to 0.01 or more, stain resistance is exhibited. By setting it to 1.0 or less, a decrease in flexibility over time is suppressed.

[0027] The method for introducing a double bond is not particularly limited, and any method known to those skilled in the art can be used, such as copolymerizing a monomer having multiple double bonds in the molecule, or producing a (meth)acrylic polymer having a functional group, and then reacting it with a compound having a functional group and a double bond that can react with the functional group.

[0028] Double bonds can also be introduced by producing a (meth)acrylic acid-based polymer under high-temperature conditions. For example, at a polymerization temperature of 100°C or higher, a cleavage reaction initiated by hydrogen abstraction from the polymer chain occurs due to the high-temperature polymerization, resulting in a polymer having an ethylenically unsaturated bond represented by the following general formula (1) at the molecular end. The polymerization temperature is preferably 120°C or higher, more preferably 150°C or higher. Higher polymerization temperatures tend to increase the double bond concentration in the polymer. The above method allows for easy and efficient production of a (meth)acrylic polymer having double bonds. Furthermore, it is possible to easily produce the polymer without the use of large amounts of impurities such as initiators or chain transfer agents for molecular weight control. Care must be taken when using chain transfer agents such as mercaptans, as they not only cause odor and coloration but also lead to deterioration of the physical properties of the adhesive. On the other hand, the upper limit of the polymerization temperature is preferably 350°C or lower to avoid the risk of coloration of the polymerization solution or a decrease in molecular weight due to decomposition reactions. Polymerization within the above temperature range allows for efficient production of copolymers with appropriate molecular weights, low viscosity, no coloration, and few impurities. That is, according to this polymerization method, it is possible to use only a very small amount of a polymerization initiator, and it is not necessary to use a chain transfer agent such as mercaptan or a polymerization solvent, and it is possible to obtain a copolymer with high purity.

[0029] [ka] [wherein M represents a monomer unit, and n is a natural number representing the degree of polymerization. 1 represents a monovalent organic group.

[0030] R in the above general formula (1) 1Examples of the alkyl group include an alkyl group, a hydroxyalkyl group, an alkoxyalkyl group, an alkyl group which may have other substituents, a phenyl group, a benzyl group, a polyalkylene glycol group, a dialkylaminoalkyl group, a trialkoxysilylalkyl group, an alkyldialkoxysilylalkyl group, and a hydrogen atom.

[0031] The (meth)acrylic polymer can be produced by conventional radical polymerization. Any of solution polymerization, bulk polymerization, and dispersion polymerization may be employed, and living radical polymerization may also be utilized. The reaction process may be any of batch, semi-batch, and continuous polymerization. Among these, high-temperature continuous polymerization at 100 to 350°C is preferred.

[0032] Generally, when crosslinkable functional groups are uniformly introduced into a polymer, the curability of a curable composition containing the polymer and the physical properties of the resulting cured product, such as heat resistance, are improved. In this regard, a process using a stirred tank reactor as the reactor is preferred because it can produce a (meth)acrylic polymer with a relatively narrow composition distribution (distribution of crosslinkable functional groups) and molecular weight distribution. Furthermore, a process using a continuous stirred tank reactor is more preferred because it narrows the composition distribution and molecular weight distribution.

[0033] High-temperature continuous polymerization methods may be performed according to known methods disclosed in, for example, Japanese Patent Application Laid-Open Nos. 57-502171, 59-6207, and 60-215007. For example, a pressurizable reactor is filled with a solvent, set to a predetermined temperature under pressure, and then a monomer mixture consisting of each monomer and, if necessary, a polymerization solvent is fed to the reactor at a constant feed rate, and an amount of polymerization liquid corresponding to the amount of monomer mixture fed is withdrawn. A polymerization initiator may also be blended into the monomer mixture as needed. If blended, the amount is preferably 0.001 to 2 parts by mass per 100 parts by mass of the monomer mixture. The pressure depends on the reaction temperature and the boiling points of the monomer mixture and solvent used, and may be any pressure that does not affect the reaction but can maintain the reaction temperature. The residence time of the monomer mixture is preferably 1 to 60 minutes. If the residence time is less than 1 minute, the monomer may not react sufficiently, and if the unreacted monomer remains for more than 60 minutes, productivity may decrease. The preferred residence time is 2 to 40 minutes.

[0034] Examples of polymerization initiators used to obtain (meth)acrylic polymers include any initiator that generates radicals at a predetermined reaction temperature. Specific examples include organic peroxides such as di-t-butyl peroxide, di-t-hexyl peroxide, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, cumene hydroperoxide, and t-butyl hydroperoxide, and azo compounds such as 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2-methylbutyronitrile), azobiscyclohexacarbonitrile, azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2-amidinopropane) dihydrochloride, and 4,4'-azobis(4-cyanovaleric acid). These polymerization initiators may be used alone or in combination. When a polymerization initiator with high hydrogen abstraction ability is used, the double bond concentration of the resulting polymer tends to be high. For example, the use of an organic peroxide rather than an azo compound tends to result in a polymer with a high double bond concentration. The amount of polymerization initiator used can be adjusted appropriately depending on the types of polymerization initiator and monomer, the desired molecular weight, polymerization conditions, etc., but is generally 0.001 to 10 parts by mass per 100 parts by mass of the monomer used. When a polymer of the same molecular weight is obtained, the double bond concentration in the obtained polymer tends to increase as the amount of polymerization initiator used decreases.

[0035] When an organic solvent is used to produce a (meth)acrylic polymer, an organic hydrocarbon compound is suitable. Examples include cyclic ethers such as tetrahydrofuran and dioxane; aromatic hydrocarbons such as benzene, toluene, and xylene; esters such as ethyl acetate and butyl acetate; ketones such as acetone, methyl ethyl ketone, and cyclohexanone; and alcohols such as methanol, ethanol, and isopropanol. One or more of these can be used. Solvents that do not dissolve the (meth)acrylic acid ester copolymer well tend to cause scale growth on the reactor walls, potentially causing production problems during cleaning processes. Furthermore, when an organic solvent with high chain transfer capacity, such as isopropanol, is used, the double bond concentration in the resulting polymer tends to be low. The amount of solvent used is preferably 80 parts by mass or less relative to 100 parts by mass of the total vinyl monomers. By using 80 parts by mass or less, a high conversion rate can be obtained in a short time. More preferably, it is 1 to 50 parts by mass. In addition, a dehydrating agent such as trimethyl orthoacetate or trimethyl orthoformate can also be added.

[0036] A known chain transfer agent may be used in the production of a (meth)acrylic polymer. When a chain transfer agent is used, the double bond concentration in the resulting polymer tends to be low. In addition, the double bond concentration generally decreases as the amount of the chain transfer agent used increases.

[0037] The reaction liquid withdrawn from the reactor can be directly used in the next step, or the polymer can be isolated by removing volatile components such as unreacted monomers, solvent, and low-molecular-weight oligomers by distillation, etc. A portion of the volatile components such as unreacted monomers, solvent, and low-molecular-weight oligomers distilled off from the reaction liquid can be returned to the raw material tank or directly to the reactor and reused in the polymerization reaction. Recycling the unreacted monomers and solvent is an economically preferable method. When recycling, it is necessary to determine the mixing ratio of the newly fed monomer mixture so as to maintain the desired monomer ratio and the desired amount of solvent in the reactor.

[0038] The amount of double bonds introduced into the polymer can be reduced by adding a radical generator and post-treating the polymer under heating conditions. The amount of radical generator added is about 0.1 to 10 parts by mass per 100 parts by mass of the polymer, and the greater the amount added, the greater the effect of reducing the double bond concentration. The heating temperature during the heat treatment is about 50 to 130°C, but the lower the temperature, the greater the effect of reducing the double bond concentration. The heating temperature is preferably in the range of 50 to 110°C, and more preferably in the range of 50 to 100°C. The heat treatment time is not particularly limited, but is preferably set so that the amount of the remaining radical generator is less than 1 mass % relative to the polymer. Those skilled in the art can calculate the amount of the remaining radicals from the activation energy, frequency factor, and reaction temperature of the radical generator used.

[0039] The double bond concentration can also be reduced by post-treatment, such as hydrogenation of the (meth)acrylic polymer. Conventional hydrogenation methods can be used. Specifically, after adding a homogeneous or heterogeneous catalyst to the polymer reaction solution, the system is immersed in a hydrogen atmosphere, heated to a pressure of from atmospheric pressure to 10 MPa and a temperature of approximately 20 to 180°C, and reacted for approximately 2 to 20 hours. Specific examples of homogeneous catalysts include rhodium complexes such as chlorotris(triphenylphosphine)rhodium, ruthenium complexes such as dichlorotris(triphenylphosphine)ruthenium and chlorohydrocarbonyltris(triphenylphosphine)ruthenium, platinum complexes such as dichlorobis(triphenylphosphine)platinum, and iridium complexes such as carbonylbis(triphenylphosphine)iridium. Heterogeneous catalysts include solid catalysts in which transition metals such as nickel, rhodium, ruthenium, palladium, and platinum are supported on carbon, silica, alumina, fibers, organic gels, and the like. Heterogeneous catalysts are preferred because they can be easily removed by filtration, resulting in stable quality and allowing expensive catalysts to be reused. The amount of catalyst added is about 10 to 1,000 ppm relative to the vinyl polymer in the case of homogeneous catalysts, and about 1,000 to 10,000 ppm in the case of heterogeneous catalysts.

[0040] <Component (B): Oxyalkylene Polymer Having Crosslinkable Silyl Groups> The oxyalkylene polymer (B) having a crosslinkable silyl group is not particularly limited as long as it contains a repeating unit represented by the following general formula (2). -OR 2 - (2) (In the formula, R 2 is a divalent hydrocarbon group. R in the above general formula (2) 2 Examples of such are as follows: (CH2)n (n is an integer from 1 to 10) CH(CH3)CH2 CH(C2H5)CH2 C(CH3)2CH2 The oxyalkylene polymer may contain one or a combination of two or more of the repeating units. Among these, CH(CH3)CH2 is preferred in terms of excellent workability.

[0041] The crosslinkable silyl group contained in the oxyalkylene polymer containing a crosslinkable silyl group is not particularly limited, and examples thereof include an alkoxysilyl group, a halogenosilyl group, a silanol group, etc., but an alkoxysilyl group is preferred in terms of ease of controlling crosslinkability. Specific examples of the alkoxysilyl group include a trimethoxysilyl group, a methyldimethoxysilyl group, a dimethylmethoxysilyl group, a triethoxysilyl group, a methyldiethoxysilyl group, a dimethylethoxysilyl group, etc. Examples include:

[0042] The method for producing an oxyalkylene polymer is not particularly limited, and examples thereof include a polymerization method using an alkali catalyst such as KOH, a polymerization method using a transition metal compound-porphyrin complex catalyst, a polymerization method using a composite metal cyanide complex catalyst, and a polymerization method using phosphazene, using a corresponding epoxy compound or diol as a raw material. The oxyalkylene polymer may be either a linear polymer or a branched polymer, or a combination of these.

[0043] The average number of crosslinkable silyl groups per molecule of the oxyalkylene polymer is preferably in the range of 1.2 to 4, more preferably 1.3 to 3.0, and most preferably 1.5 to 2.8, from the viewpoint of performance such as adhesiveness and mechanical properties of the cured product. If the number of silyl groups per molecule is less than 1.2, the curing rate of the curable composition will be slow and the mechanical properties and heat resistance will be poor. On the other hand, if the number exceeds 4, the elasticity will be insufficient. When the oxyalkylene polymer (B) having a crosslinkable silyl group is used as an elastic adhesive, polymers having 1 to 3 crosslinkable silyl groups are usually mixed in any ratio. When polymers having 2 and 3 crosslinkable silyl groups are used for this application, the ratio of parts by mass of the 2-polymer / the 3-polymer is often 70 / 30 to 10 / 90. The position of the crosslinkable silyl group contained in the oxyalkylene polymer is not particularly limited, and it may be located on the side chain and / or at the end of the polymer. The oxyalkylene polymer may be either a linear polymer or a branched polymer, or a combination of these may be used.

[0044] The number average molecular weight (Mn) of the oxyalkylene polymer having a crosslinkable silyl group is preferably 5,000 to 60,000, more preferably 10,000 to 40,000, and even more preferably 15,000 to 30,000, from the viewpoints of mechanical properties and workability.

[0045] The viscosity of the oxyalkylene polymer having a crosslinkable silyl group is preferably 4,000 to 50,000 mPa·s, more preferably 9,000 to 25,000 mPa·s at 25° C., in order to achieve both mechanical properties and heat resistance of the curable composition.

[0046] Commercially available oxyalkylene polymers having a crosslinkable silyl group may be used. Specific examples include "MS Polymer S203," "MS Polymer S303," "MS Polymer S810," "Silyl SAT200," "Silyl SAT350," "Silyl EST280," and "Silyl SAT30" manufactured by Kaneka Corporation, and "Excestar ES-S2410," "Excestar ES-S2420," "Excestar ES-S3430," and "Excestar ES-S3630" (all trade names) manufactured by AGC Inc.

[0047] The viscosity of the (meth)acrylic acid ester polymer (A) of the present invention is preferably lower than that of the polyoxyalkylene polymer (B). By doing so, component (A) acts as a diluent (viscosity reducer) for component (B) during work, improving workability. On the other hand, during curing, it is incorporated into a crosslinked network to form a tough adhesive layer. This improves heat resistance and mechanical strength.

[0048] <Curable composition> As described above, the curable composition of the present invention essentially comprises components (A) and (B). In order to obtain a cured product with good heat resistance and mechanical properties, the mass ratio of components (A) and (B) ((A) / (B)) is preferably 10 to 90 / 90 to 10, more preferably 20 to 80 / 80 to 20, and even more preferably 25 / 75 to 75 / 25.

[0049] The curable composition of the present invention may contain components other than component (A) and component (B), as long as the effects of the present invention are not impaired. Such components include fillers, plasticizers, antioxidants, curing accelerators, anti-tack agents, adhesion promoters, etc.

[0050] Examples of fillers include light calcium carbonate with an average particle size of about 0.02 to 2.0 μm, heavy calcium carbonate with an average particle size of about 1.0 to 5.0 μm, titanium oxide, carbon black, synthetic silicic acid, talc, zeolite, mica, silica, calcined clay, kaolin, bentonite, aluminum hydroxide, barium sulfate, glass balloons, silica balloons, and polymethyl methacrylate balloons. These fillers can improve the mechanical properties of the cured product, increasing its strength and elongation. Among these, light calcium carbonate, heavy calcium carbonate, and titanium oxide are preferred, as they are highly effective in improving physical properties, and a mixture of light calcium carbonate and heavy calcium carbonate is more preferred. The amount of filler added is preferably 20 to 300 parts by mass, more preferably 50 to 200 parts by mass, relative to 100 parts by mass of the total amount of components (A) and (B). When a mixture of light calcium carbonate and heavy calcium carbonate is used as described above, the mass ratio of light calcium carbonate to heavy calcium carbonate is preferably in the range of 90 / 10 to 50 / 50.

[0051] Examples of plasticizers include liquid polyurethane resins, polyester-based plasticizers obtained from dicarboxylic acids and diols; etherified or esterified polyalkylene glycols such as polyethylene glycol and polypropylene glycol; polyether-based plasticizers such as sugar-based polyethers obtained by addition polymerization of alkylene oxides such as ethylene oxide and propylene oxide to a sugar polyhydric alcohol such as sucrose, followed by etherification or esterification; polystyrene-based plasticizers such as poly-α-methylstyrene; and poly(meth)acrylates without crosslinkable functional groups. Among these, poly(meth)acrylates without crosslinkable functional groups are preferred in terms of durability, such as heat resistance, of the cured product. Among these, those with an Mw of 1,000 to 7,000 and a glass transition temperature of −30° C. or lower are more preferred.

[0052] The amount of plasticizer used in the curable composition is 1 / 2 the total amount including components (A) and (B). When it is 00 parts by mass, it is preferably in the range of 0 to 100 parts by mass, and may be in the range of 0 to 80 parts by mass, or may be in the range of 0 to 50 parts by mass.

[0053] As the anti-aging agent, ultraviolet absorbers such as benzophenone compounds, benzotriazole compounds and oxalic acid anilide compounds, light stabilizers such as hindered amine compounds, antioxidants such as hindered phenols, heat stabilizers, or anti-aging agents which are mixtures thereof can be used. Examples of ultraviolet absorbers include BASF products under the trade names "Tinuvin 571," "Tinuvin 1130," and "Tinuvin 327." Examples of light stabilizers include BASF products under the trade names "Tinuvin 292," "Tinuvin 144," and "Tinuvin 123," and Sankyo Co., Ltd. under the trade name "Sanol 770." Examples of heat stabilizers include BASF products under the trade names "Irganox 1135," "Irganox 1520," and "Irganox 1330." BASF product name "Tinuvin B75," which is a mixture of ultraviolet absorber, light stabilizer, and heat stabilizer, may also be used.

[0054] As the curing accelerator, known compounds such as tin-based catalysts, titanium-based catalysts and tertiary amines can be used. Examples of tin-based catalysts include dibutyltin dilaurate, dibutyltin diacetate, dibutyltin diacetonate, dioctyltin dilaurate, etc. Specific examples include products manufactured by Nitto Kasei Co., Ltd., such as "Neostan U-28," "Neostan U-100," "Neostan U-200," "Neostan U-220H," "Neostan U-303," and "SCAT-24." Examples of titanium catalysts include tetraisopropyl titanate, tetra-n-butyl titanate, titanium acetylacetonate, titanium tetraacetylacetonate, titanium ethyl acetylacetonate, dibutoxytitanium diacetylacetonate, diisopropoxytitanium diacetylacetonate, titanium octylene glycolate, and titanium lactate. Examples of tertiary amines include triethylamine, tributylamine, triethylenediamine, hexamethylenetetramine, 1,8-diazabicyclo[5,4,0]undecene-7 (DBU), diazabicyclononene (DBN), N-methylmorpholine, and N-ethylmorpholine.

[0055] The amount of the curing accelerator used is preferably 0.1 to 5 parts by mass, and more preferably 0.5 to 2 parts by mass, per 100 parts by mass of the total of the components (A) and (B).

[0056] Examples of adhesion promoters include aminosilanes such as those sold under the trade names "KBM602," "KBM603," "KBE602," "KBE603," "KBM902," and "KBM903" by Shin-Etsu Silicones Co., Ltd. Silanes having a ketimine structure that generates an amino group upon hydrolysis may also be used. Other compounds that may be blended include acrylic oligomers such as "Aronix M8030," "M8100," and "M309" manufactured by Toagosei Co., Ltd., "R15HT" manufactured by Idemitsu Oil Co., Ltd., "PBB3000" manufactured by Nippon Soda Co., Ltd., and "Goselaq 500B" manufactured by Nippon Synthetic Chemical Industry Co., Ltd., anti-tack agents such as tung oil, castor oil, and other fatty acid oils; dehydrating agents such as methyl orthoformate, methyl orthoacetate, and vinylsilane; and organic solvents.

[0057] The adhesive composition of the present invention may contain an epoxy resin added thereto, such as epichlorohydrin-bisphenol A epoxy resins, epichlorohydrin-bisphenol F epoxy resins, novolac epoxy resins, hydrogenated bisphenol A epoxy resins, glycidyl ether epoxy resins of bisphenol A propylene oxide adducts, p-oxybenzoic acid glycidyl ether ester epoxy resins, m-aminophenol epoxy resins, diaminodiphenylmethane epoxy resins, urethane-modified epoxy resins, various alicyclic epoxy resins, N,N-diglycidylaniline, N,N-diglycidyl-o-toluidine, triglycidyl isocyanurate, polyalkylene glycol diglycidyl ether, and hydantoin epoxy resins. Further examples include flame-retardant epoxy resins such as glycidyl ether of tetrabromobisphenol A, glycidyl ethers of polyhydric alcohols such as glycerin, and epoxidized products of unsaturated polymers such as petroleum resins, but are not limited to these, and commonly used epoxy resins can be used. Among these epoxy resins, those containing at least two epoxy groups per molecule are particularly preferred because they have high crosslinkability during curing and the cured product easily forms a three-dimensional network. Among these, bisphenol A-type epoxy resins or novolac-type epoxy resins are more preferred.

[0058] The epoxy resin is preferably blended in an amount of 1 to 100 parts by mass based on 100 parts by mass of the total polymer of the present invention (the total mass of the (meth)acrylic polymer (A) having a crosslinkable silyl group and the oxyalkylene polymer (B)). If the epoxy resin exceeds 100 parts by mass, elasticity may decrease.

[0059] When an epoxy resin is used, it is preferable to use a curing agent for the epoxy resin in combination. Examples of the curing agent for the epoxy resin include primary amines such as ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, hexamethylenediamine, diethylaminopropylamine, N-aminoethylpiperazine, isophoronediamine, diaminodicyclohexylmethane, m-xylenediamine, m-phenylenediamine, diaminodiphenylmethane, and diaminodiphenylsulfone; linear diamines represented by the formula (CH3)2N(CH2)nN(CH3)2 (wherein n is an integer of 1 to 10); and (CH3)2-N(CH2 )n-CH3 (wherein n is an integer of 0 to 10), linear tertiary amines represented by the formula N{(CH2)nCH3}3 (wherein n is an integer of 1 to 10), tetramethylguanidine, alkyl tertiary monoamines represented by the formula N{(CH2)nCH3}3 (wherein n is an integer of 1 to 10), triethanolamine, piperidine, N,N'-dimethylpiperazine, triethylenediamine, pyridine, picoline, diazabicycloundecene, benzyldimethylamine, 2-(dimethylaminomethyl)phenol, 2,4,6-tris(dimethylaminomethyl)phenol, Ramiron C-260 manufactured by BASF, Araldit manufactured by CIBA Examples of curing agents include secondary or tertiary amines such as HY-964 and Rohm and Haas's Menthenediamine, ketimines such as 1,2-ethylenebis(isopentylideneimine), 1,2-hexylenebis(isopentylideneimine), 1,2-propylenebis(isopentylideneimine), p,p'-biphenylenebis(isopentylideneimine), 1,2-ethylenebis(isopropylideneimine), 1,3-propylenebis(isopropylideneimine), and p-phenylenebis(isopentylideneimine), acid anhydrides such as phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, and benzophenonetetracarboxylic anhydride, various polyamide resins, dicyandiamide and its derivatives, and various imidazoles. The amount of such curing agent used is preferably 5 to 100 parts by mass per 100 parts by mass of the epoxy resin.

[0060] The adhesive composition provided by the present invention has a crosslinkable silyl group, so that the above-mentioned epoxy resin can be When used, the strength of the cured adhesive composition can be improved by adding a compound having a group reactive with both a crosslinkable silyl group and an epoxy group. Specific examples of compounds having a group reactive with both a crosslinkable silyl group and an epoxy group include N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltriethoxysilane, and γ-aminopropyltriethoxysilane.

[0061] The adhesive composition provided by the present invention contains the curable composition. Therefore, it can improve adhesion between the same or different substrates, such as metals, plastics, rubber, and ceramics. Furthermore, its low viscosity and fast curing rate enhance productivity, and its tough adhesive layer improves heat resistance. Therefore, it can provide an elastic adhesive that is particularly suitable for factory lines. It also has excellent weather resistance, so it can be used as an adhesive for exterior tiles, etc.

[0062] The curable composition of the present invention can be prepared as a one-component composition in which all ingredients are mixed in advance and then sealed and stored, and then cured by absorbing moisture from the air after application. Alternatively, it can be prepared as a two-component composition in which ingredients such as a curing catalyst, filler, plasticizer, and water are separately mixed as a curing agent, and the ingredients are mixed with the curable composition before use. The one-component composition is preferred because it is easy to handle and there is less chance of mixing errors during application. [Example]

[0063] The present invention will be described in detail below based on examples, but the present invention is not limited to these examples. In the following, "parts" and "%" mean parts by mass and % by mass unless otherwise specified. The methods for analyzing the polymers obtained in the Synthesis Examples, Comparative Synthesis Examples, Examples, and Comparative Examples, and the methods for evaluating the cured products obtained from the curable compositions are described below.

[0064] <Quantitative method for double bond amount> 1 By H-NMR measurement, the double bond concentration per mass of the polymer was calculated from the ratio of the integral value of the signal derived from hydrogen bonded to the double bond near 5.5 ppm to the integral value of the signal derived from hydrogen bonded to the carbon adjacent to the ester group at 3.0 to 4.5 ppm, as well as the composition of the polymer.

[0065] <Molecular weight measurement> Using a gel permeation chromatograph (model HLC-8320, manufactured by Tosoh Corporation), the polystyrene-equivalent number average molecular weight (Mn) and weight average molecular weight (Mw) were obtained under the following conditions. The molecular weight distribution (Mw / Mn) was calculated from the obtained values. Measurement conditions Column: Tosoh TSKgel SuperMultiporeHZ-M x 4 Column temperature: 40℃ Eluent: tetrahydrofuran Detector: RI

[0066] <Average Number of Crosslinkable Silyl Groups Contained in (Meth)acrylic Polymer (A)> The number (average number) f(Si) of alkoxysilyl groups, which are crosslinkable silyl groups, was calculated using the following formula from the parts by mass of the monomers having crosslinkable silyl groups when the total number of monomers constituting the polymer was taken as 100 parts by mass. f(Si) = (parts by mass of silyl group monomer) / (molecular weight of silyl group monomer × 100 / Mn)

[0067] <Average molecular weight per crosslinkable silyl group> The Mw and Mn values ​​obtained by the GPC and f(Si) were used to calculate the molecular weight using the following formula. Weight average molecular weight per crosslinkable silyl group = Mw / f(Si) Number average molecular weight per crosslinkable silyl group = Mn / f(Si)

[0068] <Viscosity of (meth)acrylic polymer> Using a TVE-20H viscometer (salt water / plate method, manufactured by Toki Sangyo Co., Ltd.), the following conditions were observed: E-type viscosity was measured. Measurement conditions Cone shape: angle 1°34′, radius 24 mm (less than 10,000 mPa·s) Angle 3°, radius 7.7mm (10000mPa s or more) Temperature: 25℃±0.5℃

[0069] <Synthesis Example 1> (Production of (meth)acrylic polymer A-1 having crosslinkable silyl groups) The temperature of a 1000 mL oil-jacketed pressurized stirred tank reactor was maintained at 200°C. Next, while maintaining the pressure of the reactor constant, a monomer mixture consisting of 60 parts of n-butyl acrylate (hereinafter referred to as "BA"), 2 parts of tetradecyl acrylate (hereinafter referred to as "TDA"), 15 parts of 3-methacryloxypropyltrimethoxysilane (hereinafter referred to as "TMS"), 5 parts of isopropyl alcohol (hereinafter referred to as "IPA"), 5 parts of trimethyl orthoacetate (hereinafter referred to as "MOA"), 10 parts of methyl ethyl ketone (hereinafter referred to as "MEK"), and 0.2 parts of di-t-hexyl peroxide (manufactured by NOF Corporation, trade name "Perhexyl D", hereinafter referred to as "DTHP") as a polymerization initiator was continuously fed from a raw material tank to the reactor at a constant feed rate (48 g / min, residence time: 12 min), and a reaction liquid equivalent to the amount of the monomer mixture fed was continuously withdrawn from the outlet. Immediately after the start of the reaction, the reaction temperature dropped once, and then a temperature rise due to the heat of polymerization was observed, but the reaction temperature was maintained at 199 to 201°C by controlling the temperature of the oil jacket. The point at which the temperature stabilized after the start of the monomer mixture supply was designated the start point for collecting the reaction solution. The reaction was continued for 25 minutes from this point, resulting in 1.2 kg of the monomer mixture being supplied and 1.2 kg of the reaction solution being collected. The reaction solution was then introduced into a thin-film evaporator, and volatile components such as unreacted monomers were separated to obtain (meth)acrylic polymer A-1. The properties of the polymer are shown in Table 1.

[0070] <Synthesis Examples 2 to 11, Comparative Synthesis Examples 1 to 3> (Production of (meth)acrylic polymers A-2 to A-11 and A-13 to A-15 having crosslinkable silyl groups) Polymerization was carried out in the same manner as in Synthesis Example 1, except that the feed composition of the monomers and solvent and the internal temperature of the reactor were changed as shown in Table 1, to obtain (meth)acrylic polymers A-2 to A-11 and A-13 to A-15. The properties of the polymers are shown in Tables 1 and 2.

[0071] Synthesis Example 12 (Production of (meth)acrylic acid polymer A-12 having crosslinkable silyl groups) Butyl acetate (100 parts) was placed in a flask equipped with a reflux condenser, and the internal temperature was maintained at 92°C in an oil bath while stirring. A mixture of BA (60 parts), TDA (25 parts), TMS (15 parts), DM (n-dodecyl mercaptan) (6.1 parts), and ABN-E (2,2'-azobis(2-methylbutyronitrile), manufactured by Nippon Finechem Co., Ltd.) (1 part) was added dropwise using a dropping funnel over 4 hours. Stirring was continued for another 3 hours while maintaining the temperature at 92°C. The reaction solution was then desolvated using an evaporator at 90°C and 10 mmHg, and the volatile components were separated to obtain (meth)acrylic polymer A-12. The properties of the polymer are shown in Table 2.

[0072] [Table 1]

[0073] [Table 2]

[0074] Details of the compounds shown in Table 1:2 are as follows: BA: butyl acrylate TDA: Tridecyl acrylate DMS: 3-methacryloxypropylmethyldimethoxysilane TMS: 3-methacryloxypropyltrimethoxysilane IPA: Isopropyl alcohol MOA: Methyl orthoacetate MEK: Methyl ethyl ketone DTHP: Di-t-hexyl peroxide DM: n-dodecyl mercaptan ABN-E: 2,2'-azobis(2-methylbutyronitrile)

[0075] <Preparation of Curable Composition> Examples 1 to 14, Comparative Examples 1 to 5 The (meth)acrylic polymer (A) having a crosslinkable silyl group obtained in the above Synthesis Example was thoroughly mixed with the oxyalkylene polymer (B) having a silyl group, manufactured by AGC Inc., under the trade names "EXCESTAR ES-S3430" (average number of crosslinkable silyl groups per molecule = 3, Mn = 20,000, viscosity at 25°C = 9,600 mPa·s, polyoxyalkylene whose main chain skeleton is made of polypropylene oxide with a branched structure and having methyldimethoxysilyl groups at the main chain terminals) and "EXCESTAR ES-S2420" (average number of crosslinkable silyl groups per molecule = 2, Mn = 16,000, viscosity at 25°C = 15,600 mPa·s, polyoxyalkylene whose main chain skeleton is made of polypropylene oxide with a linear structure and having methyldimethoxysilyl groups at the main chain terminals) in the proportions shown in Tables 3 to 5 to prepare a curable composition. Next, the curable composition and other raw materials were blended and mixed using a planetary mixer at 60°C and 10 Torr for 1 hour to obtain an adhesive composition. Each composition was evaluated for workability and curability. Furthermore, the cured products obtained from each composition were subjected to tensile property, adhesive strength, and heat resistance tests. The results are shown in Tables 3 to 5.

[0076] <Workability> The viscosity of the composition obtained by the above preparation was immediately measured (as described above) to evaluate the workability. The lower the viscosity, the better the workability was judged to be.

[0077] <Curability> The composition obtained by the above preparation was applied to a thickness of about 2 mm, and the composition was touched with a finger every 15 minutes. The time until the composition no longer adhered to the finger was recorded as the curing time.

[0078] <Sheet tensile properties> Each curable composition was applied to a Teflon (registered trademark) sheet to a thickness of 2 mm, and then heated at 23°C for 50 The cured material was then cured for one week under conditions of 50%RH to prepare a hardened sheet. A dumbbell (JIS K 6251 No. 3) was prepared and tested using a tensile testing machine (Autograph AGS -J, manufactured by Shimadzu Corporation) was used to measure the breaking elongation and breaking strength under the condition of a tensile speed of 200 mm / min. The shear strength was measured.

[0079] <Adhesion strength test> Tests were conducted using mortar boards and exterior mosaic tiles in accordance with JIS A5557 (2006) adhesive strength testing method for organic adhesives. The curable composition was applied to a mortar board (TP Giken, 10 x 50 x 50 mm) in a thickness of approximately 5 mm, and then drawn with a toothed trowel. A commercially available exterior mosaic tile (45 x 45 mm) conforming to JIS A5209 was adhered to the board. After curing for 4 weeks at 23°C and 50% RH, dedicated jigs were attached to the tile and mortar sides, and a tensile test was performed using a tensile tester (Autograph AGS-J, Shimadzu Corporation) at 23°C and a tensile speed of 3 mm / min to measure the adhesive strength.

[0080] <Heat resistance test> Each curable composition was applied to a Teflon (registered trademark) sheet to a thickness of 2 mm, and then heated at 23°C for 50 The cured material was then cured for one week under conditions of 50%RH to prepare a hardened sheet. Dumbbells (JIS K 6251 No. 3) were prepared and placed in a forced air dryer adjusted to 90°C for two weeks. The elongation at break and strength at break were measured at a tensile speed of 200 mm / min using a tensile tester (Autograph AGS-J, manufactured by Shimadzu Corporation). The retention rates of strength and elongation at break were calculated based on the tensile properties of the sheet described above.

[0081] <Stain resistance test> Each curable composition was applied to a slate board at a thickness of 3 mm and left at 23°C and 50% RH for 1 hour. After curing for a week, a hardened sheet was prepared. The hardened material was passed through a 200 mesh wire mesh to measure the contamination. Powder (8 types of test dust (manufactured by the Japan Powder Industrial Technology Association) 9g, New Ouka (manufactured by Holbein Industrial Co., Ltd.) A mixture of 27g of powder and 2g of three types of test dust (manufactured by the Japan Powder Industrial Technology Association) was sprinkled on the test piece. After leaving it to stand for a minute, the powder was removed (by air blowing and washing with water). The yellowness index (YI) was measured using the SE-2000 (YI is calculated using the following formula). The stain resistance was evaluated based on the magnitude of the yellowing index (ΔYI), which is the difference between the YI (YI0) and the YI (YI1). This was considered as one contamination test. After the measurement, leave it at 70°C for 3 hours and at 23°C for 1 hour, then sprinkle contaminated powder on it in the same way as above and measure ΔYI. This determination was counted as one cycle, and four cycles were repeated. ΔYI after four cycles is shown in Table 2. YI=100(1.28X-1.06Z) / Y (X, Y, Z are color coordinates) ΔYI = YI - YI0 (YI0 indicates YI immediately after curing)

[0082] [Table 3]

[0083] [Table 4]

[0084] [Table 5]

[0085] Details of the compounds shown in Tables 3 to 5 are as follows. UP-1110: Plasticizer (Toagosei acrylic plasticizer, product name "ARUFON UP-1110") CCR: Precipitated calcium carbonate (Shiraishi Calcium Co., Ltd., product name "Hakuenka CCR") Super SS: Heavy calcium carbonate (manufactured by Maruo Calcium Co., Ltd., product name "Super SS") R820: Titanium oxide (manufactured by Ishihara Sangyo Kaisha, product name "Tipake R820") Tinuvin B75: Anti-aging agent (manufactured by BASF Japan Ltd., product name "Tinuvin B75") U220H: Dibutyltin diacetylacetonate (manufactured by Nitto Kasei Co., Ltd., trade name "Neostan U220H") OFS-6020: 3-(2-aminoethyl)aminopropyltrimethoxysilane (manufactured by Dow-Toray Industries, Inc., trade name "DOWSIL OFS-6020") Z-6300: Vinyltrimethoxysilane (manufactured by Dow-Toray Industries, Inc., trade name "DOWSIL Z-6300")

[0086] The evaluation results are as follows: Compared with an adhesive composition using only an oxyalkylene polymer (B) having a crosslinkable silyl group (Comparative Example 5), the compositions of the present invention (Examples 1 to 14) were superior in all aspects of workability, curability, adhesive strength, and heat resistance. Furthermore, the comparative examples were inferior to the examples in the following respects. Regarding the (meth)acrylic polymer (A) having crosslinkable silyl groups, when Comparative Synthesis Example 1 (the number of silyl groups per molecule is 1.17) was used (Comparative Example 1), the curability was poor, and when Comparative Synthesis Example 2 (the number of silyl groups per molecule is 3.33) was used (Comparative Example 2), the polymer became too hard and the tensile elongation was poor. When Comparative Synthesis Example 3, in which (A) had a high viscosity and a large Mw, was used (Comparative Example 3), the workability was extremely poor compared to the Examples. In the (A) / (B) ratio, if there was too much (B), the curability, workability, and heat resistance decreased, and if there was too much (A), the flexibility was impaired (Comparative Example 4). When A-12, which has a double bond below the detection limit (Example 14), was used, the stain resistance was insufficient compared to when A-1 to A-6, which have double bonds (Examples 1 to 4, Examples 9 and 10), were used. Note that "-" in the stain resistance column in Tables 3 and 4 indicates that the measurement was not performed. [Industrial Applicability]

[0087] The curable composition of the present invention cures at room temperature and has excellent workability, curability, tensile properties, and heat resistance, making it suitable for use as an elastic adhesive in factory lines. Furthermore, since it is expected to have good stain resistance and high weather resistance, it can also be used as an adhesive for exterior tiles used at outdoor construction sites.

Claims

1. A curable composition comprising a (meth)acrylic polymer (A) having a crosslinkable silyl group and an oxyalkylene polymer (B) having a crosslinkable silyl group, the (meth)acrylic polymer (A) has 1.5 to 3.0 crosslinkable silyl groups per molecule and a viscosity at 25°C of 1,000 mPa·s to 7,000 mPa·s; the oxyalkylene polymer (B) has 1.2 to 4 crosslinkable silyl groups per molecule and a viscosity at 25°C of 4,000 mPa·s to 50,000 mPa·s; the amounts of the (meth)acrylic polymer (A) and the oxyalkylene polymer (B) used are in a mass ratio of 10 to 90 / 90 to 10; A curable composition having a viscosity at 25°C of 230 Pa·s or less.

2. The curable composition according to claim 1, wherein the (meth)acrylic polymer (A) has a number average molecular weight (Mn) of 2,000 to 6,000, and a ratio of the number average molecular weight (Mn) to the weight average molecular weight (Mw), Mw / Mn, of 1.5 to 2.

7.

3. 3. The curable composition according to claim 1 or 2, wherein the (meth)acrylic polymer (A) contains, among all monomer units constituting the (meth)acrylic polymer, 70 to 98 mass% of (meth)acrylic monomer units and 2 to 30 mass% of monomer units having a crosslinkable silyl group, and when the (meth)acrylic monomer units contained in the (meth)acrylic polymer (A) are taken as 100 parts by mass, a content of a (meth)acrylic acid alkyl ester monomer having an alkyl group having 4 or more carbon atoms is 60 to 100 parts by mass.

4. The (meth)acrylic polymer (A) has an alkyl group having 4 or more carbon atoms ( Among the meth)acrylic acid alkyl ester monomers, those having an alkyl group having 10 or more carbon atoms The (meth)acrylic acid alkyl ester monomer unit accounts for 10% of the total (meth)acrylic monomers. The curable composition according to claim 3, wherein the amount of the curable composition is 4 to 40 parts by mass when the amount of the curable composition is 0 parts by mass.

5. The curable composition according to any one of claims 1 to 4, wherein the monomer having a crosslinkable silyl group that constitutes the (meth)acrylic polymer (A) is a silyl group-containing (meth)acrylic acid ester.

6. The curable composition according to any one of claims 1 to 5, wherein the (meth)acrylic polymer (A) has double bonds in an amount of 0.01 meq / g to 1.0 meq / g.

7. The curable composition according to any one of claims 1 to 6, wherein the oxyalkylene polymer (B) has a number average molecular weight (Mn) of 5,000 to 60,000.

8. The curable composition according to any one of claims 1 to 7, which contains, as a curing accelerator, one or more compounds selected from the group consisting of tin-based catalysts, titanium-based catalysts, and tertiary amines.

9. An adhesive composition comprising the curable composition according to any one of claims 1 to 8.

10. The method for producing a curable composition according to any one of claims 1 to 8, wherein the (meth)acrylic polymer (A) is produced by a high-temperature continuous polymerization method.

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