JP6990401B2 - Curable composition - Google Patents

Description

The present invention relates to a curable composition.

Conventionally, a curable composition containing a polymer having a crosslinkable silyl group as a main component has been known. Curable compositions are used in a variety of applications such as paints, coatings, adhesives, pressure sensitive adhesives, sealants and sealants.

The crosslinkable silyl group of the polymer is hydrolyzed and dehydrated and condensed to form a siloxane bond by the water contained in the atmosphere or the adherend, whereby the curable composition is cured. This gives a cured product with excellent adhesive strength.

However, the adhesiveness of the curable composition largely depends on the compatibility with the adherend, and depending on the adherend, the curable composition may not adhere. In order to improve the adhesiveness of the curable composition to the adherend, the adherend may be treated with corona discharge, plasma discharge, direct flame, etc. to modify the surface of the adherend or the surface of the adherend. Is subjected to surface modification treatment such as primer treatment.

On the other hand, the corona discharge treatment and the plasma discharge treatment require large-scale equipment, and the direct flame treatment has a problem that it cannot be used when the heat resistance of the adherend is low. Further, the primer treatment requires a drying step and has a problem of inefficiency.

Therefore, Patent Document 1 discloses a curable composition containing two kinds of organic polymers containing a specific reactive silicon group and a specific amidine compound.

WO2007 / 094274

However, there is a problem that the adhesiveness of the curable composition of Patent Document 1 is still insufficient.

The present invention provides a curable composition having excellent adhesiveness to an adherend without subjecting the adherend to surface modification treatment such as surface treatment and primer treatment.

The curable composition of the present invention comprises a polyalkylene oxide having an average of 1.5 or more hydrolyzable silyl groups per molecule and a number average molecular weight of 15,000 or more, an amidine compound, and a tin-based silanol condensation catalyst. And an organic solvent.

[Polyalkylene oxide]
The polyalkylene oxide contained in the curable composition has a hydrolyzable silyl group. The hydrolyzable silyl group is a group in which 1 to 3 hydrolyzable groups are bonded to a silicon atom.

The hydrolyzable group of the hydrolyzable silyl group is not particularly limited, and is, for example, 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, or a mercapto. Groups, alkenyloxy groups and the like can be mentioned.

Among them, as the hydrolyzable silyl group, an alkoxysilyl group is preferable because the hydrolysis reaction is mild. The alkoxysilyl group includes a triethoxysilyl group such as a trimethoxysilyl group, a triethoxysilyl group, a triisopropoxysilyl group, and a triphenoxysilyl group; a propyldimethoxysilyl group, a methyldimethoxysilyl group, and a methyldiethoxysilyl group. Dialkoxysilyl groups such as; and monoalkoxysilyl groups such as dimethylmethoxysilyl group and dimethylethoxysilyl group. Of these, a dialkoxysilyl group is more preferable, a dimethoxysilyl group is particularly preferable, and a methyldimethoxysilyl group is most preferable.

The polyalkylene oxide has an average of 1.5 or more hydrolyzable silyl groups in one molecule, and preferably has 1.5 to 4 hydrolyzable silyl groups. .. When the number of hydrolyzable silyl groups in the polyalkylene oxide is within the above range, it is possible to provide a curable composition capable of forming a cured product having excellent rubber elasticity. The polyalkylene oxide preferably has a hydrolyzable silyl group at at least one of both ends of the molecular chain.

The average number of hydrolyzable silyl groups per molecule in the polyalkylene oxide is the concentration of the hydrolyzable silyl groups in the polyalkylene oxide determined by ¹ H-NMR and the polyalkylene determined by the GPC method. It can be calculated based on the number average molecular weight of the oxide.

As the polyalkylene oxide, the main chain has a general formula:-(RO) _n- (in the formula, R represents an alkylene group having 1 to 14 carbon atoms, and n is the number of repeating units and is positive. A polymer containing a repeating unit represented by) is preferably mentioned. The main clavicle of the polyalkylene oxide may consist of only one repeating unit or may consist of two or more repeating units.

Examples of the main chain skeleton of polyalkylene oxide include polyethylene oxide, polypropylene oxide, polybutylene oxide, polytetramethylene oxide, polyethylene oxide-polypropylene oxide copolymer, and polypropylene oxide-polybutylene oxide copolymer. Of these, polypropylene oxide is preferable. According to polypropylene oxide, the adhesiveness of the curable composition is excellent, and the rubber elasticity of the cured product obtained by curing the curable composition is excellent.

The number average molecular weight of the polyalkylene oxide is 15,000 or more, preferably 15,000 to 50,000, more preferably 15,000 to 40,000, and particularly preferably 21,000 to 35,000. When the number average molecular weight of the polyalkylene oxide is 15,000 or more, the rubber elasticity of the cured product of the curable composition is excellent. When the number average molecular weight of the polyalkylene oxide is 50,000 or less, the coatability of the curable composition is improved.

The number average molecular weight of the polyalkylene oxide is a value converted by polystyrene using a gel permeation chromatography (GPC) method. For example, it can be measured with the following measuring device and measuring conditions.

<Measuring device>
Product name "Waters 2690" manufactured by Waters
<Measurement conditions>
Column: Shodex GPC KF800D
(4.6mm ID250mm) x 2 Column temperature: 40 ° C
Mobile phase: Tetrahydrofuran (0.3 mL / min)
Sample concentration: 0.2% by mass
Detector: RI WATERS product name "2414"

As the polyalkylene oxide containing a hydrolyzable silyl group, commercially available ones can be used. For example, as polyalkylene oxides having a main chain skeleton of polypropylene oxide and having a methyldimethoxysilyl group at the end of the main chain skeleton, the product name "Exester S3430" manufactured by Asahi Glass Co., Ltd. and the product name manufactured by Kaneka Corporation. Examples thereof include "SAT-350", "HS-2" and "SAX-750".

[Amidine compound]
The curable composition contains an amidine compound. The amidine compound may form a complex. As the amidine compound, phenylbiguanide is preferable, 1-tolylbiguanide is preferable, and 1- (o-tolyl) biguanide is more preferable because the adhesiveness to the polyvinyl chloride resin and the mortar plate is improved.

Examples of the polyvinyl chloride-based resin include a homopolymer of a vinyl chloride monomer, a copolymer of a vinyl chloride monomer and another monomer copolymerizable therewith, and the like. The other monomer copolymerizable with the vinyl chloride monomer is not particularly limited, and examples thereof include vinyl acetate and ethylene.

When the amidine compound is contained in the curable composition, the curing of the polyalkylene oxide can be promoted and a cured product having high adhesiveness can be produced. Further, the amidine compound bleeds out to the surface of the curable composition, improving the adhesiveness with the adherend and improving the adhesiveness of the curable composition.

The amidine compound is preferably dissolved in an organic solvent and then mixed with a polyalkylene oxide in order to improve the adhesiveness of the curable composition.

In the curable composition, the content of the amidine compound is preferably 1 to 10 parts by mass, more preferably 1 to 6 parts by mass, and particularly preferably 1 to 4 parts by mass with respect to 100 parts by mass of the polyalkylene oxide.

When the content of the amidine compound is 1 part by mass or more, the cured product of the curable composition has excellent adhesiveness to the adherend without subjecting the adherend to a surface modification treatment. When the content of the amidine compound is 10 parts by mass or less, bleeding out of the amidine compound to the surface of the cured product can be suppressed and contamination of the adherend can be prevented.

[Tin-based silanol condensation catalyst]
The curable composition contains a tin-based silanol condensation catalyst. The tin-based silanol condensation catalyst is a catalyst for accelerating the dehydration condensation reaction between silanol groups formed by hydrolyzing the hydrolyzable silyl group contained in the polyalkylene oxide. The silanol group means a hydroxy group (≡Si—OH) directly bonded to a silicon atom.

The tin-based silanol condensation catalyst is not particularly limited as long as it contains a tin atom in the molecule, and is, for example, dibutyltin diacetylacetonate, dibutyltin dilaurate, dibutyltin oxide, dibutyltin dimethoxide, and dibutyltin bis (nonyl). Phenoxide), dibutyltin acetate, dibutyltin phthalate, dibutyltin (2-ethylhexanoate), bis (dibutyltin lauric acid) oxide, dibutyltin bis (acetylacetonate), dibutyltin bis (ethylacetoacetonate) , Dibutyltin bis (monoestermalate), dibutyltin octate, dibutyltin dilaurate, bis (dibutyltin bistriethoxysilicate) oxide, and dibutyltin oxybisethoxysilicate, dibutyltin oxybisethoxysilicate, dioctyltin distearate, dioctyl Examples thereof include tin oxide, dioctyl tin dilaurate, dioctyl tin diacetate, dioctyl tin dineodecanoate, and dioctyl tin bis (ethylmalate). As the tin-based silanol condensation catalyst, dibutyl tin diacetylacetonate is preferable. The tin-based silanol condensation catalyst may be used alone or in combination of two or more.

The content of the tin-based silanol condensation catalyst in the curable composition is preferably 0.05 to 5.0 parts by mass, more preferably 0.2 to 5.0 parts by mass with respect to 100 parts by mass of the polyalkylene oxide. 0.3 to 4.0 parts by mass is particularly preferable. By setting the content of the tin-based silanol condensation catalyst within the above range, the adhesiveness of the curable composition to the adherend can be improved.

When the amidin compound and the tin-based silanol condensation catalyst are contained in the curable composition, the curing rate of the polyalkylene oxide is dramatically higher than when the amidin compound or the tin-based silanol condensation catalyst is contained alone. The cured product of the curable composition becomes a viscous solid, and the adhesiveness of the curable composition to the adherend is improved. It is considered that this is because the amidine compound enhances the activity of the polyalkylene oxide and the tin-based silanol condensation catalyst and promotes the cross-linking reaction of the polyalkylene oxide.

In the curable composition, the ratio of the content of the amidin compound to the content of the tin-based silanol condensation catalyst (content of the amidin compound / content of the tin-based silanol condensation catalyst) is preferably 1 to 10 and preferably 1 to 6. Is more preferable, 1 to 5 is particularly preferable, and 1 to 3.5 is most preferable. When the ratio of the content of the amidine compound to the content of the tin-based silanol condensation catalyst is within the above range, the adhesiveness of the curable composition to the adherend is improved.

[Organic solvent]
The curable composition contains an organic solvent. The organic solvent can improve the adhesiveness of the curable composition to the adherend by dissolving the amidine compound and uniformly containing the amidine compound in the curable composition at the molecular level.

Examples of the organic solvent include alcohols such as ethyl alcohol, methyl alcohol and propyl alcohol, glycol ethers such as ethylene glycol monotersial butyl ether, diethylene glycol methyl ether, ethylene glycol isopropyl ether, ethylene glycol propyl ether and diethylene glycol isopropyl ether, and ethyl acetate. Examples include esters such as, and ketones such as acetone. The organic solvent may be used alone or in combination of two or more.

As the organic solvent, alcohol is preferable, and ethyl alcohol is more preferable, because the open time of the curable composition can be lengthened by exchanging the alkoxide with the hydrolyzable silyl group of the polyalkylene oxide. Glycol ether is preferable, and ethylene glycol monotarsial butyl ether is more preferable, because the adhesiveness of the curable composition to the adherend is improved.

When the organic solvent has a hydroxyl group (-OH group), it is preferable that the number of carbon atoms bonded to the carbon atom to which the hydroxyl group is bonded is one. When the organic solvent has a hydroxyl group (-OH group), the organic solvent preferably has -CH ₂ OH. This is because the curing rate of the curable composition can be improved, the content of the organic solvent can be reduced, and the environment in which the curable composition can be used can be improved.

The content of the organic solvent in the curable composition is preferably 3 parts by mass or more, more preferably 5 parts by mass or more, particularly preferably 6 parts by mass or more, and 6.5 parts by mass or more with respect to 1 part by mass of the amidine compound. Is the most preferable. The content of the organic solvent in the curable composition is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and particularly preferably 15 parts by mass or less with respect to 1 part by mass of the amidine compound. When the content of the organic solvent in the curable composition is 3 parts by mass or more, the adhesiveness of the curable composition to the adherend can be improved. When the content of the organic solvent in the curable composition is 30 parts by mass or less, the adhesiveness of the curable composition to the adherend can be improved.

[Filler]
The curable composition preferably further contains a filler. Since the curable composition contains a filler, excellent rubber elasticity can be imparted to the cured product of the curable composition, and the adhesiveness of the curable composition is improved.

As the filler, an inorganic filler is preferably mentioned. Examples of the inorganic filler include calcium carbonate, calcium oxide, aluminum oxide, silicon dioxide, ferrous oxide, potassium oxide, quartz, zinc oxide, magnesium oxide and the like. Of these, calcium carbonate is preferable. The filler may be used alone or in combination of two or more.

The filler may be surface-treated. As the surface treatment, surface treatment with organic compounds such as saturated fatty acid, unsaturated fatty acid, logonic acid and resin acid, and surface treatment with metal or semi-metal such as silane coupling agent, titanate coupling agent and zirconium coupling agent. And so on.

The content of the filler in the cured composition is preferably 100 to 300 parts by mass, more preferably 130 to 210 parts by mass with respect to 100 parts by mass of the polyalkylene oxide. When the content of the filler is within the above range, excellent rubber elasticity can be imparted to the cured product of the curable composition, and the adhesiveness of the curable composition is improved.

[Silane coupling agent]
The curable composition preferably further contains a silane coupling agent. By using the silane coupling agent in combination with the polyalkylene oxide, the adhesiveness of the curable composition can be further improved.

Examples of the silane coupling agent include aminosilane coupling agent, epoxysilane coupling agent, isocyanate silane coupling agent, mercaptosilane coupling agent, carboxysilane coupling agent, halogen silane coupling agent, carbamate silane coupling agent, and alkoxysilane. Coupling agents, acid anhydride silane coupling agents and the like can be mentioned. Among them, an aminosilane coupling agent is preferable because the adhesiveness of the curable composition is improved by the synergistic effect with the polyalkylene oxide. The silane coupling agent may be used alone or in combination of two or more.

Examples of the aminosilane coupling agent include 3-aminopropyltrimethoxysilane, 3-aminopropylmethyldimethoxysilane, 3-aminopropyltriethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, and N-. (2-Aminoethyl) -3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) -3-aminopropyltriethoxysilane, N, N'-bis- [3- (trimethoxysilyl) propyl] ethylenediamine , N, N'-bis- [3- (triethoxysilyl) propyl] ethylenediamine, N, N'-bis- [3- (methyldimethoxysilyl) propyl] ethylenediamine, N, N'-bis- [3-( Examples thereof include trimethoxysilyl) propyl] hexamethylenediamine and N, N'-bis- [3- (triethoxylyl) propyl] hexamethylenediamine.

Among them, the aminosilane coupling agents include 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, and N- (2-aminoethyl) -3-propyltriethoxy. Silane is preferred, with N- (2-aminoethyl) -3-aminopropyltrimethoxysilane being more preferred.

The content of the silane coupling agent in the curable composition is preferably 0.5 to 10 parts by mass, more preferably 1 to 5 parts by mass with respect to 100 parts by mass of the polyalkylene oxide. By setting the content of the silane coupling agent to 0.5 parts by mass or more, the adhesiveness of the curable composition can be improved. By setting the content of the silane coupling agent to 10 parts by mass or less, it is possible to suppress deterioration of the storage stability and handleability of the curable composition.

[Plasticizer]
The curable composition preferably further contains a plasticizer. By using the plasticizer, excellent rubber elasticity can be imparted to the cured product of the curable composition, and the workability of the curable composition is improved.

Examples of the plasticizer include phthalates such as dioctylphthalate, dibutylphthalate, acrylic skeleton polymer and butylbenzylphthalate, and polyalkylene oxides such as polypropylene glycol. The plasticizer may be used alone or in combination of two or more.

The content of the plasticizer in the curable composition is preferably 100 parts by mass or less, more preferably 70 parts by mass or less, and particularly preferably 1 to 70 parts by mass with respect to 100 parts by mass of the polyalkylene oxide. If the content of the plasticizer in the curable composition is too high, the plasticizer may bleed and the strength tends to decrease.

[Dehydrating agent]
The curable composition of the present invention preferably further contains a dehydrating agent. According to the dehydrating agent, it is possible to prevent the curable composition from being cured by the moisture contained in the air when the curable composition is stored.

Examples of the dehydrating agent include vinyltrimethoxysilane, hexadecyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane, dimethyldimethoxysilane, tetraethoxysilane, methyltrimethoxysilane, and methyltriethoxysilane. Silane compounds such as tetramethoxysilane, phenyltrimethoxysilane, and diphenyldimethoxysilane; and ester compounds such as methyl orthoate, methyl orthoacetate, and ethyl orthoacetate can be mentioned. These dehydrating agents may be used alone or in combination of two or more. Of these, vinyltrimethoxysilane is preferable as the dehydrating agent.

The content of the dehydrating agent in the curable composition is preferably 0.5 to 30 parts by mass, more preferably 1 to 10 parts by mass with respect to 100 parts by mass of the polyalkylene oxide.

[Other additives]
The curable composition may contain other additives such as thixotropic agents, antioxidants, light stabilizers, pigments, dyes, antioxidants, solvents and the like.

Examples of the antioxidant include a hindered phenolic antioxidant, a bishindered phenolic antioxidant, a less hindered phenolic antioxidant, a polyphenolic antioxidant and the like, and examples thereof include hindered phenolic antioxidants. Agents and bishindadphenolic antioxidants are preferred. The content of the antioxidant in the curable composition is preferably 0.1 to 20 parts by mass, more preferably 0.3 to 10 parts by mass with respect to 100 parts by mass of the polyalkylene oxide.

Examples of the light stabilizer include benzotriazole-based ultraviolet absorbers, benzophenone-based ultraviolet absorbers, hindered amine-based light stabilizers, and benzotriazole-based ultraviolet absorbers, and hindered amine-based light stabilizers are preferable. The content of the light stabilizer in the curable composition is preferably 0.1 to 20 parts by mass, more preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the polyalkylene oxide.

The curable composition can be rapidly cured from the surface to the inside by the moisture in the air or the moisture contained in the adherend. The curable composition has excellent adhesion to the adherend without subjecting the adherend to treatments such as corona discharge treatment, plasma discharge treatment, direct flame treatment, and surface modification treatment such as primer treatment. Has sex. Further, the curable composition forms a cured product that exhibits high tensile strength and rubber hardness from the initial stage of curing.

Such curable compositions include adhesives for civil engineering, construction, vehicles, electrical products, electronic components, miscellaneous goods, sealants, coating agents, sealants and sealants, and for civil engineering or construction. It can be used for various purposes as a coating agent and a primer for a base material.

The curable composition of the present invention has excellent adhesiveness to the adherend without subjecting the adherend to surface modification treatment such as surface treatment and primer treatment.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.

The following raw materials were used in the production of the curable compositions of Examples and Comparative Examples.

[Polyalkylene oxide]
Polyalkylene oxide (A1) having a main chain of polypropylene oxide and a methyldimethoxysilyl group at the end of the main chain (average number of methyldimethoxysilyl groups per molecule: 2.1, number average molecular weight: 22000, Kaneka product name "SAT-350")
Polyalkylene oxide (A2) having a main chain of polypropylene oxide and a methyldimethoxysilyl group at the end of the main chain (average number of methyldimethoxysilyl groups per molecule: 2.0, number average molecular weight: 20000, Asahi Glass Co., Ltd. product name "S-3430")

[Amidine compound]
1- (o-trill) biguanide (B1) (Product name "Noxeller BG" manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd.)
・ Phenyl biguanide (B2) (manufactured by Tokyo Chemical Industry Co., Ltd.)

[Tin-based silanol condensation catalyst]
-Tin-based silanol condensation catalyst (C) (dibutyltin diacetylacetonate, product name "U-220H" manufactured by Nitto Kasei Co., Ltd.)

[Organic solvent]
・ Ethyl alcohol ・ Acetone ・ Methyl alcohol ・ Ethylene glycol monotersial butyl ether (Product name “Swasolve ETB” manufactured by Maruzen Petrochemical Co., Ltd.)

・ Filler (calcium carbonate, product name "Calfine 200M" manufactured by Maruo Calcium Co., Ltd.)
-Silane coupling agent (N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, product name "KBM603" manufactured by Shin-Etsu Chemical Co., Ltd.]
-Plasticizer (acrylic skeleton polymer, product name "UP1110" manufactured by Toagosei Co., Ltd.)
-Dehydrating agent (vinyltrimethoxysilane, product name "KBM-1003" manufactured by Shin-Etsu Chemical Co., Ltd.)

(Examples 1 to 9 and Comparative Examples 1 to 7 )
The polyalkylene oxide, the tin-based silanol condensation catalyst, the filler, the silane coupling agent, the plasticizer, and the dehydrating agent were uniformly kneaded under reduced pressure in a sealed stirrer so as to have the predetermined amounts shown in Table 1. ..

Next, the amidine compound and the organic solvent were mixed at 23 ° C., and the liquid amidine compound was dissolved in the organic solvent to prepare a mixed solution. This mixed solution was supplied into the above stirrer and kneaded uniformly to prepare a curable composition.

The adhesiveness of the obtained curable composition was measured in the following manner, and the results are shown in Table 1.

(Adhesiveness)
The curable composition was applied flatly on a substrate at 23 ° C. and a relative humidity of 50% so as to be 500 g / m ² .

Next, after allowing the curable composition to stand for 60 minutes, a substrate of the same material was placed on the curable composition, and the substrates were bonded to each other via the curable composition. After the substrates are bonded together, they are cured for one week to cure the curable composition to form a cured product, and then using a universal tensile tester (manufactured by Instron) at a speed of 3 mm / min. A tensile test or a 180 ° peel test was performed at a speed of 50 mm / min. The state of destruction of the substrate was visually observed and evaluated based on the following criteria.

5. The cured product of the curable composition was 100% destroyed, or a part of the substrate was destroyed.
4. The cured product of the curable composition was broken at 75% or more and less than 100% of the adhesive area.
3. The cured product of the curable composition was broken at 50% or more and less than 75% of the adhesive area.
2. The cured product of the curable composition was broken in less than 50% of the adhesive area.
1. 100% fracture occurred at the interface between the cured product of the curable composition and the substrate.

As the base material, a vinyl chloride steel plate (trade name "Unibond" manufactured by Nippon Steel & Sumikin Kenzai Co., Ltd.), a polyvinyl chloride sheet, an ABS resin sheet and a mortar plate were prepared.

When a vinyl chloride steel sheet (trade name "Unibond" manufactured by Nippon Steel & Sumikin Kenzai Co., Ltd.), an ABS resin sheet and a mortar plate were used, a tensile test was performed. When a polyvinyl chloride sheet was used, a 180 ° peeling test was performed.

Claims (5)

100 parts by mass of polyalkylene oxide having an average of 1.5 or more hydrolyzable silyl groups per molecule and a number average molecular weight of 15,000 or more, 1 to 10 parts by mass of an amidin compound, and a tin-based silanol condensation catalyst. , With an organic solvent containing at least one of alcohol and glycol ether ,
The ratio of the content of the amidine compound to the content of the tin-based silanol condensation catalyst (content of the amidine compound / content of the tin-based silanol condensation catalyst) is 1 to 10 and
A curable composition characterized in that the content of the organic solvent is 2.0 parts by mass or more and 30 parts by mass or less with respect to 1 part by mass of the amidine compound . The curable composition according to claim 1, wherein the amidine compound contains phenylbiguanide. The curable composition according to claim 1, wherein the amidine compound contains 1-tolylbiguanide. The curable composition according to claim 1, wherein the amidine compound contains 1- (o-tolyl) biguanide. The curable composition according to any one of claims 1 to 4, wherein the organic solvent contains ethyl alcohol.