JPH0463113B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a primer used for the purpose of improving adhesive strength when bonding substrates with an α-cyanoacrylate instant adhesive. Conventional technology α-cyanoacrylate instant adhesives have fast curing properties and are popular as adhesives for industrial and household use, but they do not provide sufficient adhesive strength depending on the type of substrate. There are cases. Therefore, in Japanese Patent Publication No. 43-5004, adhesive strength is imparted to synthetic resin bodies where α-cyanoacrylate instant adhesives such as polyethylene, polypropylene, polyformaldehyde, and polyfluorinated ethylene exhibit almost no adhesive properties. In order to
A method has been proposed in which the surface of these synthetic resin bodies is treated in advance with an inorganic basic substance or an organic basic substance. Among these, examples of organic basic substances include formamide, dimethylformamide, dimethylacetamide, ethylamine, triethylamine,
Monoethanolamine, diethanolamine, pyridine, and pyrroline are listed. Similarly, in Japanese Patent Publication No. 47-8718, a base material such as Bakelite, polyvinyl chloride, polyethylene, acrylonitrile-styrene copolymer, natural rubber, etc. A method of treating with phosphine oxide is disclosed in Japanese Patent Publication No. 49-12094, in which base materials such as polyester, nylon, polyacetal, and aluminum are treated in advance with diethylamine, o-phenylenediamine, dimethyl-p-
Toluidine, diethyl-p-toluidine, N.N.
A method of treatment with diethylaniline, trichloroacetamide, and succinimide is disclosed. In addition, in Japanese Patent Publication No. 59-66471, wood, paper,
A curing accelerator composition for cyanoacrylate instant adhesives consisting of a homogeneous solution of three components: an amine compound with a boiling point of 50 to 250°C, a deodorizing agent, and a solvent was proposed for the purpose of accelerating the curing of instant adhesives when bonding leather. Examples of amine compounds include triethylamine, diethylamine, butylamine, isopropylamine, dibutylamine, tributylamine, N,N-dimethylaniline, N,N-diethylaniline, N,N-dimethyl-p-toluidine, , N-dimethyl-m-toluidine, N,N
-dimethyl-o-toluidine, dimethylbenzylamine, pyridine, picoline, vinylpyridine,
Ethanolamine, propanolamine, and ethylenediamine are listed. Problems to be Solved by the Invention However, there are many organic basic substances and amine compounds mentioned above that do not improve adhesive strength, and even if they do not improve adhesive strength to certain plastic substrates. Even when using substrates of the same grade, there are large variations in adhesive strength, and even when the grades are different, the adhesive strength can drop significantly. Even with a certain type of plastic base material, the adhesive strength varies greatly depending on the case, and the adhesive strength decreases due to differences in grades. It is very difficult to work with, and it is strongly desired that a constant and sufficient adhesive force be obtained at all times. The present invention was made as a result of extensive research in order to meet such demands. Means for Solving the Problems The α-cyanoacrylate instant adhesive primer of the present invention contains (1) 4-vinylpyridine as an essential component, β-picoline/or/and 3,4-
A compound containing lutidine as an optional component or a solvent solution thereof, more preferably (2) 4-vinylpyridine and β-picoline as essential components, 3,4
- A compound containing lutidine as an optional component or a solvent solution thereof. The above primer is suitable as a primer for a substrate that exhibits non-adhesion or low adhesion to α-cyanoacrylate instant adhesives. The primer of the present invention contains 4-vinylpyridine as an essential component. Even if it is vinylpyridine, 2-vinylpyridine has poor effectiveness as a primer. Although 4-vinylpyridine alone has an excellent effect of improving adhesive strength, it is particularly preferable to use 4-vinylpyridine in combination with β-picoline, and 4-vinylpyridine is combined with 3,4-lutidine. It is also preferable to use it in combination with Furthermore, it is particularly preferable to use 4-vinylpyridine, β-picoline, and 3,4-lutidine in combination. The mixing ratio of each component when used together is 4-vinylpyridine.
For each 100 parts by weight, β-picoline and 3,4-lutidine are often selected from a range of 1 to 100 parts by weight, but are not necessarily limited to this range. In general, when other amine compounds are mixed with 4-vinylpyridine, they often react, but β-picoline and/or 3,4-lutidine do not react even when mixed with 4-vinylpyridine; By using 4-vinylpyridine alone, superior adhesive strength can be exhibited regardless of the type and type of substrate. The primer of the present invention is composed of the above-mentioned compound or its solvent solution, and is used by applying it to a substrate by means such as dipping, spraying, or dropping, and then drying it. When used in the form of a solution, solvents include alcohols such as methanol, ethanol, n-propanol, and isopropanol, ketones such as acetone and methyl ethyl ketone, hydrocarbons such as n-hexane, n-heptane, benzene, toluene, and xylene, and diethyl. Ethers such as ether, tetrahydrofuran and dioxane, esters such as methyl acetate, ethyl acetate and benzyl acetate, fluorine-containing solvents,
Examples include chlorinated solvents and water, and two or more of these can also be used in combination. The concentration of the above compound in the solvent solution is not particularly limited, but it is desirably at least 0.01% by weight or more, preferably 0.1% by weight; if it is less than 0.01% by weight, no initial adhesive strength improvement effect can be expected. The base material to be treated with the above primer may be made of any material, including polyolefin (polyethylene, polypropylene, etc.), polyacetal, polyamide, polyester, fluorine-based polymer, silicone, or α-cyano such as polyvinyl chloride. The greatest feature of the present invention is that it can be applied to bonding substrates that cannot be bonded or have poor adhesive strength with acrylate instant adhesives, or to bond these substrates to polar substrates. After the polymer is applied to the base material, it is dried naturally or by wiping, and then the base material is bonded with an α-cyanoacrylate instant adhesive. For α-cyanoacrylate-based instant adhesives, the formula Any group in which R is an alkyl group, alkenyl group, alkynyl group, cycloalkyl group, aryl group, alkoxyalkyl group, etc. can be used. α-cyanoacrylate instant adhesive is
It may also contain conventionally known additives such as polymerization inhibitors, thickeners, heat resistance imparters, plasticizers, colorants, and the like. The present invention is useful in various industrial and household fields because it exhibits stable adhesive strength regardless of the type or type of substrate. Function The primer of the present invention is applied to the surface of the substrate to be adhered prior to adhesion, and then adhesion is performed using an α-cyanoacrylate instant adhesive. In this case, the primer exhibits the effect of exhibiting sufficient adhesive strength regardless of the type or type of substrate. EXAMPLES Next, the present invention will be explained in more detail with reference to Examples. Below, Primer A refers to a 2% acetone solution of 4-vinylpyridine, and Primer B refers to 4-vinylpyridine 1.8%, β-picoline.
Acetone solution containing 0.2%, Primer C is 4-vinylpyridine 1.6%, β-picoline
This is an acetone solution containing 0.2% of 3,4-lutidine and 0.2% of 3,4-lutidine. Example 1 Prepare a 3-grade polypropylene sheet with a thickness of 2 mm, degrease its surface, and then size it to 25 mm x 100 mm.
A test piece was prepared, and one end of the test piece was coated with the primer of Example and the primer of Comparative Example (1 to 10
% acetone solution), then pulled out and left for a while to volatilize the acetone. Next, one primer-treated side of this test piece was
After applying ethyl cyanoacrylate to an area of 25 mm x 25 mm, attach the other test piece, and
Apply a load of Kg/cm ² and leave for 5 hours, 20℃, 65%
Adhesive shear strength was measured under RH conditions according to JIS. The results are shown in Table 1. In Table 1, base material 1a, base material 1b, and base material 1c are polypropylene test pieces of different grades. Also, Max, Min.
These are the maximum and minimum values of the measured values for each of the five test pieces. (See Table 1) As is clear from Table 1, the primers of the present invention, especially Primer B , Primer C
It can be seen that the adhesive exhibits stable and strong adhesive strength regardless of the grade of polypropylene.

【table】

[Table] 2 # indicates base material destruction example 2 A polyacetal test piece with a thickness of 2 mm and a size of 25 mm x 100 mm, with a thickness of 2 mm of a different grade from this,
Prepare a polyacetal test piece with a size of 25 mm x 100 mm and a polyethylene test piece with a thickness of 2 mm and a size of 25 mm x 100 mm. After degreasing the surface, one end of the test piece was coated with the primer of the example and the primer of the comparative example. It was immersed in a primer (1 to 10% acetone solution), then pulled out, and left to stand for a while to volatilize the acetone. Next, ethyl cyanoacrylate was applied to one primer-treated surface of this test piece, the other test piece was bonded, and the adhesive shear strength was measured in the same manner as in Example 1. The results are shown in Table 2. In Table 2, base material 2a and base material 2b are polyacetal test pieces of different grades, and base material 3 is a polyethylene test piece. Furthermore, Max. and Min. are the maximum and minimum values of the measured values for each of the five test pieces.

【table】

[Table] 2 # indicates base material destruction example 3 A silicone rubber test piece with a thickness of 2 mm and a size of 25 mm x 100 mm was prepared, and this test piece was treated with primer A, primer B, and primer C, respectively.
As a result of examining the adhesive shear strength of ethyl cyanoacrylate in the same manner as in Example 1, good adhesive strength was obtained in all cases, and the adhesive strength was particularly excellent when treated with Primer B and Primer C. In addition, as comparative examples, α-picoline, pyridine,
Test pieces were treated with 2-chloropyridine, 2-vinylpyridine, hexamethylenediamine, N-methyl-2-pyrrolidone, and N-vinyl-2-pyrrolidone, and the shear strength of the adhesive with ethylcyanoacrylate was similarly investigated. In either case, almost no adhesive force was obtained. Effects of the Invention If the surface of a substrate is treated with the primer of the present invention and then bonded with an α-cyanoacrylate instant adhesive, polyolefins, polyacetals, polyamides, polyesters, fluoropolymers, silicones, polychlorides, etc. Good adhesion is achieved even on substrates that exhibit non-adhesion or low adhesion to α-cyanoacrylate instant adhesives, such as vinyl. Moreover, in this case, there is little variation in adhesive strength regardless of the grade of the base material or the difference in the surface condition, and a stable adhesive force can always be obtained, making the adhesive work extremely easy.

Claims (1)

[Scope of Claims] 1. A primer for an α-cyanoacrylate instant adhesive comprising a compound containing 4-vinylpyridine as an essential component and β-picoline or/and 3,4-lutidine as an optional component, or a solvent solution thereof. 2. The primer according to claim 1, which comprises a compound containing 4-vinylpyridine and β-picoline as essential components and 3,4-lutidine as an optional component, or a solvent solution thereof. 3. The primer according to claim 1, wherein the primer is a primer for a substrate that exhibits non-adhesion or low adhesion to α-cyanoacrylate instant adhesives. 4. The base material exhibiting non-adhesion or low adhesion to α-cyanoacrylate instant adhesives is polyolefin, polyacetal, polyamide, polyester, fluoropolymer, silicone, or polyvinyl chloride. Primer according to item 3.