JP7054301B2 - 2-Cyanoacrylate-based adhesive composition - Google Patents

Description

The present invention relates to an improvement in a 2-cyanoacrylate adhesive composition known as an instant adhesive.

2-Cyanoacrylate-based adhesives start polymerization with a small amount of water adhering to the surface of the adherend due to the unique anionic polymerizable property of 2-cyanoacrylate, which is the main component, and cure to form various materials. It can be firmly adhered in a short time. Therefore, it is widely used as a so-called instant adhesive in fields such as industrial use, medical use, and household use.

However, while a general 2-cyanoacrylate adhesive has an excellent bonding rate (curing rate), the cured product has a high cohesive force and a large volume shrinkage rate during polymerization, so that the cured product is hard. It is brittle, and in order to maintain the adhesive strength after bonding, it is required to improve the flexibility or brittleness of the cured product. As one of the methods for improving the flexibility or brittleness of the cured product, a method of adding an elastomer or an elastomer and other additives to a 2-cyanoacrylate adhesive is known (for example, Patent Documents 1 to 4). ).

Japanese Unexamined Patent Publication No. 6-271817 Japanese Unexamined Patent Publication No. 8-239899 Japanese Unexamined Patent Publication No. 6-57214 Japanese Unexamined Patent Publication No. 2013-112766

It was found that the addition of the elastomer improved the flexibility of the cured product, while changing the properties of the adhesive and increasing the spinnability. When the spinnability of the adhesive increases, it is difficult to improve the filling speed because the thread generated when filling the container contaminates the filling machine, or the thread generated when using the adhesive. Causes problems such as contaminating adherends and the like.

Therefore, an object of the present invention is to provide a 2-cyanoacrylate adhesive composition having improved spinnability while improving the flexibility or brittleness of the cured product.

As a result of diligent research by the present inventors to solve the above-mentioned problems, an adhesive composition containing an elastomer is usually imparted with a thixophilic property to the adhesive composition, so-called jelly-like (gel-like) adhesive. It has been found that the spinnability is improved by adding a small amount of fumed silica added in an amount of several parts by weight or more with respect to 100 parts by weight of 2-cyanoacrylate. Specifically, the following inventions are included.

[1] A 2-cyanoacrylate-based adhesive composition containing 2-cyanoacrylate, an elastomer and fumed silica, wherein 1 to 30 parts by weight of an elastomer and 0 parts of fumed silica are used with respect to 100 parts by weight of 2-cyanoacrylate. An adhesive composition containing .001 to 0.5 parts by weight.

[2] The adhesive composition according to [1], wherein the content of fumed silica is 0.005 to 0.2 parts by weight with respect to 100 parts by weight of 2-cyanoacrylate.

[3] The adhesive composition according to [1] or [2], which has a thixotropy index of 1.5 or less.

[4] The adhesive composition according to any one of [1] to [3], wherein the elastomer is a copolymer containing a structural unit derived from acrylic acid, acrylonitrile and acrylic acid alkyl ester in its structure.

According to the present invention, it is possible to provide a 2-cyanoacrylate-based adhesive composition having improved flexibility or brittleness of a cured product and improved spinnability. In particular, since the adhesive composition is superior in fluidity as compared with the jelly-like adhesive, it is possible to provide an adhesive composition that is easy to apply to the surface of an adherend and maintains spreadability.

Further, the 2-cyanoacrylate-based adhesive composition of the present invention, like a general 2-cyanoacrylate-based adhesive composition, has no cloudiness and is excellent in transparency, so that the transparency of the adhesive composition is particularly high. It can be suitably used in the required field.

In the present invention, for example, 2-cyanoacrylate represented by the following general formula (1) is used.

（式中Ｒ_１は炭素数１～１６の置換基を有していてもよい飽和または不飽和の脂肪族基もしくは脂環族基又は炭素数６～１６の置換基を有してもよいアリール基もしくはアラルキル基を示す。）

(In the formula, R ₁ may have a saturated or unsaturated aliphatic group or an alicyclic group which may have a substituent having 1 to 16 carbon atoms or an aryl which may have a substituent having 6 to 16 carbon atoms. Indicates a group or an unsaturated group.)

Specific examples of 2-cyanoacrylate include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, octyl, neopentyl, cyclohexyl, ethylhexyl, dodecyl, allyl, and methoxyethyl 2-cyanoacrylate. , Ethyl, methoxypropyl, benzyl, phenyl, chloroethyl, tetrahydrofurfuryl and other esters. In addition, these 2-cyanoacrylates may be used alone or in combination of two or more as required.

As the elastomer used in the present invention, one having rubber-like elasticity at 20 ° C. and one generally added to a 2-cyanoacrylate-based adhesive composition can be used. Specific examples of such an elastomer include an acrylic acid ester-based copolymer elastomer (for example, ethylene / methyl acrylate / acrylic acid copolymer, ethylene / methyl acrylate / butyl acrylate / acrylic acid copolymer, ethylene).・ Ethylene / acrylic acid ester / acrylic acid copolymer such as methyl methacrylate / methacrylic acid copolymer, ethylene / vinyl acetate / acrylic acid copolymer, butadiene / methyl acrylate / acrylic acid copolymer, butadiene / acrylonitrile・ Acrylic acid copolymer, acrylonitrile, acrylic acid ester, acrylic acid copolymer, acrylonitrile, acrylic acid ester, acrylic acid ester having a hydroxyl group, acrylic acid copolymer, butadiene, acrylonitrile, acrylic acid ester, acrylic acid Polymers, butadiene, styrene, acrylonitrile, methyl acrylate, acrylic acid copolymer, etc.), styrene-butadiene copolymer system elastomer, polyurethane-based elastomer, chloroprene-based elastomer, carboxylated acrylonitrile-butadiene copolymer-based elastomer, polyester-based elastomer , Fluorine-based elastomer, polyisoprene-based elastomer, epichlorohydrin-based elastomer, ethylene-propylene copolymer system elastomer, ethylene-vinyl acetate copolymer system elastomer, thermoplastic urethane elastomer, etc., and these elastomers are one type or, if necessary, 2 Seeds or more may be used together.

Among the above-mentioned elastomers, acrylic acid ester-based copolymer elastomers are preferable because they can easily improve the adhesive properties of 2-cyanoacrylate-based adhesive compositions, and in particular, structural units derived from acrylic acid, acrylonitrile, and acrylic acid alkyl esters are used. Copolymers contained in the structure are preferred.

The content of the elastomer contained in the adhesive composition of the present invention is usually 1 to 30 parts by weight, preferably 2 to 20 parts by weight, based on 100 parts by weight of 2-cyanoacrylate. By setting the content to 1 part by weight or more and 30 parts by weight or less, an adhesive composition having a sufficient adhesion speed can be obtained while sufficiently improving the flexibility or brittleness of the cured product.

The fumed silica used in the present invention is an anhydrous silica of ultrafine powder (primary particles of 500 nm or less, particularly 1 to 200 nm) produced by oxidation in a vapor phase state in a high-temperature flame using silicon tetrachloride as a raw material. Means that. The fumed silica includes highly hydrophilic hydrophilic silica and highly hydrophobic hydrophobic silica. In the present invention, either silica may be used, and if necessary, both silicas may be used in combination. May be good.

Among the fused silicas, examples of hydrophilic silica include Aerosil 50, 130, 200, 300 and 380 manufactured by Nippon Aerosil, Leolosil QS-10, QS-20, QS-30 and QS-40 manufactured by Tokuyama Corporation. Will be. Examples of the hydrophobic silica include Aerosil RY200, R202, R805, R811, R812, R974, R972, R976 manufactured by Nippon Aerosil Co., Ltd.

The content of fumed silica contained in the adhesive composition of the present invention is usually 0.001 to 0.5 parts by weight, preferably 0.002 to 0.2 parts by weight, based on 100 parts by weight of 2-cyanoacrylate. Particularly preferably, it is 0.005 to 0.2 parts by weight. When the content is 0.001 part by weight or more, the spinnability of the adhesive composition is sufficiently improved, and when the content is 0.5 part by weight or less, the adhesive composition does not become cloudy, especially the adhesive. It can be suitably used in fields where transparency of the composition is required. In addition, an adhesive composition that maintains good coatability and spreadability can be obtained.

Since the adhesive composition of the present invention has low ticking property and is excellent in fluidity, it is characterized by being an adhesive composition that is easy to apply to the surface of an adherend and maintains spreadability. Therefore, the ticko index measured by the method described in Examples described later is usually 1.5 or less, preferably 1.3 or less.

The viscosity of the adhesive composition of the present invention can be appropriately determined depending on the intended use, but the viscosity at 20 ° C. measured by the method described in Examples described later is preferably 5000 mPa · s or less. By setting the viscosity to 5000 mPa · s or less, it becomes easy to apply the adhesive composition to the adherend, it spreads easily on the adherend, and it becomes possible to adhere without impairing workability.

In addition to 2-cyanoacrylate, elastomer and fumed silica, the adhesive composition of the present invention may contain various additives generally used in 2-cyanoacrylate-based adhesive compositions, if necessary. .. Hereinafter, the additives that may be contained will be described in detail.

<Aromatic multivalent hydroxy compound>
As an aromatic polyvalent hydroxy compound that can be contained in the 2-cyanoacrylate adhesive composition of the present invention, for example, the following general formula (2)

（上記一般式（２）中、Ｒはカルボキシル基またはアルコキシカルボニル基を表す。また、ｍは２～５の整数を表し、ｎは０～４の整数を表す。）
で表される化合物が挙げられる。上記一般式（２）で表される芳香族多価ヒドロキシ化合物として具体的に例えば、ピロガロール、１，２，４－トリヒドロキシベンゼン、フロログルシノール、ベンゼンテトラオール、ベンゼンヘキサオール、レゾルシン、ガーリック酸、ガーリック酸エチル、ガーリック酸メトキシエチル等が挙げられる。芳香族多価ヒドロキシ化合物１種または必要に応じ２種以上を併用してもよい。芳香族多価ヒドロキシ化合物を添加する場合の添加量として例えば、２－シアノアクリレート１００重量部に対して０．００１～５．０重量部であり、好ましくは０．０１～１．０重量部である。芳香族多価ヒドロキシ化合物を添加することによって、接着後の耐熱性、耐水性等を向上することができる。

(In the above general formula (2), R represents a carboxyl group or an alkoxycarbonyl group, m represents an integer of 2 to 5, and n represents an integer of 0 to 4.)
Examples thereof include compounds represented by. Specific examples of the aromatic polyvalent hydroxy compound represented by the general formula (2) include pyrogallol, 1,2,4-trihydroxybenzene, phloroglucinol, benzenetetraol, benzenehexaol, resorcin, and garlic acid. , Ethyl garlicate, methoxyethyl garlicate and the like. One aromatic polyvalent hydroxy compound or two or more aromatic compounds may be used in combination if necessary. When the aromatic multivalent hydroxy compound is added, the amount added is, for example, 0.001 to 5.0 parts by weight, preferably 0.01 to 1.0 parts by weight, based on 100 parts by weight of 2-cyanoacrylate. be. By adding an aromatic multivalent hydroxy compound, heat resistance, water resistance and the like after adhesion can be improved.

<Curing accelerator>
Examples of the curing accelerator that can be contained in the 2-cyanoacrylate-based adhesive composition of the present invention include polyalkylene oxide derivatives and calix allene compounds.

As a polyalkylene oxide derivative, for example, the following general formula (3)

（上記一般式（３）中、Ｘ_１ およびＸ_２ は、それぞれ独立して水素原子、ハロゲン原子、水酸基、置換若しくは無置換のアルキル、アルケニル、アリール又はアラルキル基を示す。ｐは１以上の整数、ｑは２以上の整数を示し、末端は環形成されていてもよい。）
で表される繰り返し単位を有する化合物が挙げられる。

(In the above general formula (3), X ₁ and X ₂ independently represent a hydrogen atom, a halogen atom, a hydroxyl group, a substituted or unsubstituted alkyl, alkenyl, aryl or aralkyl group, respectively. P is an integer of 1 or more. , Q indicates an integer of 2 or more, and the terminal may be ring-formed.)
Examples thereof include compounds having a repeating unit represented by.

Among the polyalkylene oxide derivatives represented by the general formula (3), specific examples of the chain polyalkylene oxide derivative include formaldehyde condensate, acetaldehyde condensate, trioxane, and polyalkylene glycol (for example, diethylene glycol and triethylene glycol). , Tetraethylene glycol, polyethylene glycol (400, 1000, etc.), dipropylene glycol, polypropylene glycol, polytetramethylene oxide, poly 3,3-bis (chloromethyl) butylene oxide, poly 1,3-dioxolane, ethylene oxide-propylene oxide Block polymer, etc.), Polyalkylene glycol monoether (eg, methyl carbitol, carbitol, diethylene glycol-n-butyl ether, diethylene glycol phenyl ether, diethylene glycol benzyl ether, dipropylene glycol ethyl ether, tripropylene glycol methyl ether, polyethylene glycol methyl ether) , Polyethylene glycol propyl ether, polyethylene glycol lauryl ether, polyethylene glycol stearyl ether, polyoxyethylene nonylphenyl ether, polyethylene glycol allyl ether, etc.), polyalkylene glycol diether (eg, diethylene glycol diethyl ether, diethylene glycol di-n-butyl ether, tri). Ethylene glycol dimethyl ether, tetraethylene glycol distearyl ether, polyethylene glycol dimethyl ether, etc.), polyalkylene glycol monoester (eg, diethylene glycol monopropionate, tetraethylene glycol monoacetate, tripropylene glycol mono-n-butyrate, polyethylene glycol monoacetate) , Polyethylene glycol monopropionate, polyethylene glycol laurate, polyethylene glycol sebacate, polyethylene glycol stearate, polyethylene glycol oleate, polyoxyethylene sorbitan monolaurate, diethylene glycol acrylate, diethylene glycol methacrylate, diethylene glycol clothonate, etc.), Polyalkylene Glycol diesters (eg, diethylene glycol diacetate, diethylene glycol dipropionate, diethylene glycol) Diacrylate, diethylene glycol distearate, diethylene glycol dimethacrylate, tetraethylene glycol dicrotonate, polyethylene glycol diacetate, polyethylene glycol di-n-butyrate, polyethylene glycol diuralate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, polyethylene glycol Dicrotonate, polyethylene glycol di-2-cyanoacrylate, polyethylene glycol stearyl-methacrylate, polyethylene glycol lauryl-acrylate, etc.), Polyalkylene glycol monoether monoester (eg, methylcarbitol, carbitol, diethylene glycol monoethyl ether, diethylene glycol) Aacrylate, methacrylate, crotonate, etc. of glycol monoether compounds such as monomethyl ether, polyethylene glycol monomethyl ether, polyethylene glycol monoethyl ether, tetraoxyethylene glycol monomethyl ether, polyoxyethylene glycol monolauryl ether, and polyoxyethylene glycol monononylphenyl ether. ), Bisphenol A-polyalkylene oxide adduct, trimethylolpropane-polyalkylene oxide adduct, glycerin-polyalkylene oxide adduct, adipic acid-polyalkylene oxide adduct, trimellitic acid-polyalkylene oxide adduct, etc. Be done.

Among the polyalkylene oxide derivatives represented by the above general formula (3), specific examples of the cyclic polyalkylene oxide derivative are 18-crown-6-ether, 15-crown-5-ether, and 18-crown-5. -Ether, dithio-15-crown ether, dibenzo-18-crown-6-ether, dicyclohexyl-18-crown-6-ether, 1,2-naphtho-15-crown-5-ether, 1,2-methylbenzo- 18-crown-6-ether and the like can be mentioned.

As the calixarene compound, for example, 37,38,39,40,41,42-hexa- (2-ethoxy-2-oxoethoxy) -calix [6] allen, 25,26,27,28-tetra- (2-). Ethoxy-2-oxoethoxy) -calix [4] allen, 4-tert-butyl calix [6] allen-0,0', 0'', 0''', 0'''', 0'''' ''-Hexaethyl hexaacetate, 4-tert-butylcalix [5] Allen-0,0', 0'', 0'''', 0''''-pentaethyl pentaacetate, 4-tert-butylcalix [4] Allen-0,0', 0'', 0'''-tetraethyl tetraacetate and the like can be mentioned.

The above-mentioned curing accelerator may be used alone or in combination of two or more as required. The amount of the curing accelerator added is, for example, 0.005 to 5.0 parts by weight, preferably 0.01 to 1.0 parts by weight, based on 100 parts by weight of 2-cyanoacrylate. ..

<Other additives>
The 2-cyanoacrylate-based adhesive composition of the present invention includes the above-mentioned aromatic polyvalent hydroxy compound, curing accelerator, stabilizer (for example, hydroquinone, hydroquinone monomethyl ether, t-butylcatechol, catechol, pyrogallol, etc.). Radical polymerization inhibitor, alkyl sulfonic acid such as sulfur dioxide, methane sulfonic acid, trifluoromethane sulfonic acid, aromatic sulfonic acid such as p-toluene sulfonic acid, trifluorinated boron complex such as trifluorinated boron diethyl ether complex, Anionic polymerization inhibitors such as borosulfonic acid and trialkylbolate), plasticizers (eg dimethyl phthalate, diethyl phthalate, diisodecyl phthalate, triethyl acetyl citrate, tributyl acetyl citrate, etc.), fragrances, solvents, strength Various additives generally used in 2-cyanoacrylate-based adhesive compositions such as improvers, aliphatic polyvalent carboxylic acids, and aromatic polyvalent carboxylic acids may be contained.

The present invention will be described with examples, but the present invention is not limited to these examples.

<Test method>
(1) Appearance A sample was prepared by a method conforming to JIS K6861-4 and visually confirmed.

(2) Transmittance ratio The ratio (=) of the transmittance measured with the following measuring device and measurement conditions when the value of the adhesive composition (Comparative Example 1) to which fumed silica is not added is 1.00. The transmittance of the adhesive composition of each Example / Comparative Example / the transmittance of the adhesive composition of Comparative Example 1) is described.
Measuring device: UV-2700 manufactured by Shimadzu Corporation
Cell used: Polystyrene cell manufactured by AS ONE 12.5 x 12.5 x 4 mm
Measurement wavelength: 550 nm

(3) Viscosity Measured under the following conditions.
Equipment: TVE-25 type viscometer manufactured by Toki Sangyo Co., Ltd. Measurement temperature: 20 ° C
Rotation speed: 1 rpm
The low viscosity Example 5 was measured at 20 rpm, and Comparative Example 5 was measured at 100 rpm.

(4) Thixotropy index It was expressed as a ratio between the viscosity measured in (3) above and the viscosity obtained when the rotation speed was set to 1/10 in (3) above. In Comparative Example 5, the viscosity of the sample was very low, and the viscosity could not be measured when the rotation speed was set to 1/10, so that the sample was set to − (blank).

(5) Spinning property About 1 g of the adhesive was sucked up from the container with a polyspoid, and the spinning thread length at the time of ejection was measured and evaluated according to the following criteria.
Less than 2 cm: ○, 2-5 cm: △, 5 cm or more: ×

(6) Set time (seconds)
It was measured by a method according to JIS K6861-8.

(7) Tension-shear adhesive strength (N / mm ² )
It was measured by a method according to JIS K6861-6.

(8) T peeling adhesive strength (N / mm)
It was measured by a method according to JIS K6854.

(Example 1)
11 parts by weight of acrylic acid / acrylonitrile / butyl acrylate copolymer (“Leocoat R-1020” manufactured by Toray Coatex) as an elastomer and ultrafine powder as fumed silica with respect to 100 parts by weight of ethyl-2-cyanoacrylate. 0.1 part by weight of anhydrous silica (Aerodil 200 manufactured by Nippon Aerodil Co., Ltd.), SO ₂ 30 ppm as anionic polymerization inhibitor, methanesulfonic acid 10 ppm and HBF ₄₁₀ ppm, and hydroquinone 1000 ppm as a radical polymerization inhibitor were added at 40 ± 2 ° C. The adhesive composition was prepared by stirring at the same temperature for 24 hours. After the preparation, each of the above-mentioned tests was carried out on the obtained 2-cyanoacrylate adhesive composition. The results are shown in Table 1.

(Examples 2 to 10, Comparative Examples 1 to 4)
An adhesive composition was prepared by the same operation as in Example 1 except that the elastomer, fumed silica and other additives were changed as shown in Tables 1 and 2, and each of the above tests was carried out. The results are shown in Tables 1 and 2.

In the following Tables 1 and 2, unless otherwise specified, the amount used represents the amount (parts by weight) of each component used with respect to 100 parts by weight of ethyl-2-cyanoacrylate. The abbreviation of each additive in the table means the following compounds and the like.

A-1: Acrylic acid / acrylonitrile / butyl acrylate copolymer (manufactured by Toray Coatex, "Leocoat R-1020")
A-2: Acrylic acid / acrylonitrile / butyl acrylate copolymer (manufactured by Toray Coatex, "Leocoat R-9000")
A-3: Ethylene / acrylic acid ester / acrylic acid copolymer ("Vamac VMX4017" manufactured by DuPont Co., Ltd.)
A-4: Thermoplastic urethane ("Desmocol 400/1" manufactured by Sumika Covestro Urethane Co., Ltd.)
B-1: Ultrafine powdery anhydrous silica ("Aerosil 200" manufactured by Nippon Aerosil Co., Ltd.)
B-2: Ultrafine powdery anhydrous silica ("Aerosil RY-200S" manufactured by Nippon Aerosil Co., Ltd.)
C-1: Garlic acid C-2: Pyrogallol D-1: Methoxypolyethylene glycol # 400 methacrylate D-2: 15-crown-5-ether

Claims (3)

A 2-cyanoacrylate adhesive composition containing 2-cyanoacrylate, an elastomer and fumed silica, wherein 1 to 30 parts by weight of the elastomer and 0.005 parts by weight of fumed silica are used with respect to 100 parts by weight of 2 -cyanoacrylate. ~ 0. An adhesive composition containing 2 parts by weight. The adhesive composition according to claim 1 , wherein the thixotropy index is 1.5 or less. The adhesive composition according to claim 1 or 2 , wherein the elastomer is a copolymer containing a structural unit derived from acrylic acid, acrylonitrile and acrylic acid alkyl ester in its structure.