JPH0757859B2 - α-Cyanoacrylate adhesive composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to an α-cyanoacrylate-based adhesive composition, and more specifically, it is provided with thixotropic properties,
In addition, the present invention relates to an α-cyanoacrylate adhesive composition having excellent storage stability and adhesive strength.

[Conventional technology]

The main component of the α-cyanoacrylate adhesive is an α-cyanoacrylate represented by the following formula [I], and this monomer has a property of rapidly anionically polymerizing due to the water present in the air or on the solid surface. ing.

(In the formula, R is alkyl having 1 to 16 carbons, alkenyl,
It represents a group such as aralkyl, haloalkyl, cycloalkyl and aryl. The α-cyanoacrylate adhesive is a one-component solventless adhesive obtained by modifying the monomer by adding various additives as necessary.

By the way, since an α-cyanoacrylate adhesive generally has a low viscosity, when it is applied to a vertical surface, a flow-down phenomenon occurs and drops easily occur. There is also a risk of irritation if the drops accidentally touch the skin. Further, with respect to porous materials such as wood and ceramics, the adhesive liquid is easily absorbed in the porous tissue, resulting in poor adhesion. As described above, since the α-cyanoacrylate adhesive has a low viscosity, it has a problem in handling and the object to be bonded is limited.

Conventionally, as a method for solving this problem, for example,
63-37150 proposes to use, as a thixotropic agent, a modified silica having a cumulative film formed by a silane coupling agent to completely cover the hydrophilic groups on the surface of fine particle silica. However, the modified silica has insufficient dispersibility in the α-cyanoacrylate adhesive, the obtained composition is unstable and the storage stability is poor, and the extension fluctuation of the initial set time after a long set time elapses. It has a defect such as coming.

[Problems to be Solved by the Invention]

The object of the present invention is to obtain α having excellent thixotropic properties.
-To provide a cyanoacrylate-based adhesive composition.

Another object of the present invention is to provide an α-cyanoacrylate-based adhesive composition having excellent stability and using silica having good dispersibility as a thixotropic agent, which is highly stable and whose set time does not change with the passage of time. is there.

The inventors of the present invention have conducted extensive studies to overcome the above-mentioned problems of the prior art. As a result, the hydrophilic silica having a hydrophilic group (silanol group) on its surface is hydrophobized with a zirconium-based coupling agent to obtain the silica. By dispersing and mixing a thixotropic agent consisting of a modified silica having a monomolecular film of a lipophilic residue formed on at least a part of the hydrophilic groups on the surface thereof by mixing with an α-cyanoacrylate adhesive, it is possible to achieve the above object, The present invention has been completed based on the findings.

[Means for Solving the Problems]

According to the present invention, α-cyanoacrylate-based adhesive composition characterized by comprising modified silica obtained by surface-treating hydrophilic silica with a zirconium-based coupling agent as a thixotropic agent. Things are offered.

Hereinafter, the present invention will be described in detail.

The α-cyanoacrylate used in the present invention is a compound represented by the above general formula [I], and specific examples of R include, for example, methyl, ethyl, n-, i-propyl and n.
-, I-, sec, tert-butyl, amyl, n-hexyl, 2
-Ethylhexyl, octyl, dodecyl, allyl, propargyl, cyclohexyl, methoxyethyl, tetrahydrofurfuryl, benzyl, phenyl, 2-chloroethyl, trifluoroethyl, methyl cellosolve, ethyl cellosolve, 2-methoxyisopropyl and the like.
Among these, those in which R is a lower alkyl group such as methyl, ethyl, propyl, and butyl are preferable because they have a fast set time and high adhesive strength. These α-cyanoacrylates are used alone or in combination of two or more.

The α-cyanoacrylate-based adhesive composition of the present invention includes
Generally used anionic polymerization inhibitors (for example, sulfur dioxide, sulfonic acid, paratoluenesulfonic acid, methanesulfonic acid, etc.), radical polymerization inhibitors (for example, hydroquinone, hydroquinone monomethyl ether, etc.), fragrances, dyes, pigments, A plasticizer and the like can be added as appropriate.

The α-cyanoacrylate adhesive composition of the present invention contains an organic polymer compound as a thickener in an amount of 0.1% by weight to 3% by weight.
It is desirable to add 0% by weight, preferably 3 to 10% by weight.

Examples of such an organic polymer compound include polymethyl methacrylate, polyacrylate, polyvinyl acetate, polyvinyl butyral, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyether, polyester, polycyanoacrylate resin and the like. These can be used alone or in combination of two or more.

In the present invention, as the thixotropic agent, modified silica obtained by hydrophobizing hydrophilic fine particle silica having a hydrophilic group (silanol group) on the surface with a zirconium coupling agent is used. By hydrophobizing with a zirconium-based coupling agent, a monomolecular film of a lipophilic residue is formed on a part or all of the hydrophilic groups on the silica surface.

As the zirconium-based coupling agent, for example, butoxytriisosteroyl zirconate, butoxytrioctanonyl zirconate, butoxy tris (dioctyl pyrophosphate) zirconate and the like are suitable.

The modified silica is blended as a thixotropic agent in the α-cyanoacrylate adhesive composition in an amount of 1 to 20% by weight, preferably 2 to 6% by weight.

〔Example〕

Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples.

[Experimental Example of Preparation of Modified Silica] 10 g of Aerosil # 200 (trade name of Nippon Aerosil Co., Ltd.) was used as the hydrophilic silica, and deaeration was carried out at 200 ° C. under a reduced pressure of 1 mmHg for 2 hours to remove water contained therein, followed by drying. Disperse it in 10 times the amount of toluene (special grade reagent), and then add butoxytriisostearoyl zirconate as a zirconium coupling agent in a predetermined amount (Aerosil # 200).
0.1 to 100% by weight of the above) as a standard, the reaction is carried out within the range of room temperature to 80 ° C. for 2 to 5 hours while dropping into the toluene solution, and then filtration and washing are repeated 2 to 3 times to form fine particles. Modified silica is obtained.

[Examples 1 and 2] To 100 parts by weight of ethyl α-cyanoacrylate, 0.05 parts by weight of hydroquinone as a radical polymerization inhibitor and 0.003 parts by weight of paratoluenesulfonic acid as an anion polymerization inhibitor were added, and polymethyl was used as a thickener. Methacrylate (pMMA) and modified silica surface-treated with the zirconium-based coupling agent obtained in the above Preparation Example as a thixotropic agent were added at the compounding ratio (% by weight) shown in Table 1.

Various physical properties were measured using the α-cyanoacrylate-based adhesive composition thus obtained. The results are shown in Table 1.

The methods for measuring the physical properties are as follows.

<Set time> Measured in accordance with JIS K-6861 "Testing method for α-cyanoacrylate adhesives" (8. set time).

<Tensile shear strength> The tensile shear strength was measured according to JIS K-6861 "Testing method for α-cyanoacrylate adhesives" (6. Tensile shear adhesive strength).

<Stability> According to JIS K-6861 “Testing method for α-cyanoacrylate adhesives” (10. Storage stability), the α-cyanoacrylate adhesive composition was placed in a thermostatic chamber at 70 ± 2 ° C for 5 hours.
After holding for 20 days and 20 days, the set time and appearance were immediately measured in comparison with those of the blank.

[Comparative Examples 1 to 3] [alpha] -Cyanoacrylate-based adhesive compositions were obtained in the same manner as in Examples except that commercially available hydrophobic silica was used in the proportions shown in Table 1, and the physical properties were measured in the same manner. . The results are shown in Table 1.

As is clear from Table 1, the α-cyanoacrylate adhesive composition of the present invention is superior to the conventional ones in terms of set time, stability and adhesive strength.

〔The invention's effect〕

Since the α-cyanoacrylate adhesive composition of the present invention is a gel (jelly) adhesive, there is no flow-down phenomenon at the time of application to a vertical surface and no liquid dripping, so that it is unintentional or careless. It does not hang on your clothes or skin, and there is no risk of irritation if you accidentally touch it. Moreover, not only to the metallic material but also to the permeation is suppressed, so that it has an excellent effect such as exhibiting sufficient adhesion ability to the porous material such as wood and ceramics.

Claims (1)

[Claims] 1. An α-cyanoacrylate adhesive composition comprising α-cyanoacrylate containing modified silica obtained by surface-treating hydrophilic silica with a zirconium coupling agent as a thixotropic agent. .