JP3798502B2 - Primer and adhesion method of hardly adherent adherend - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a primer that can remarkably improve the adhesive force when adhering difficult-to-adhere adherends such as silicone rubber and fluororesin with a 2-cyanoacrylate adhesive . Moreover, it is related with the method of adhere | attaching a difficult-to-adhere adherend with a 2-cyanoacrylate adhesive using the primer.
[0002]
[Prior art]
2-Cyanoacrylate-based instant adhesives are fast-curing and are therefore widely used as industrial and household adhesives. However, they can hardly exhibit adhesive strength with silicone rubber and fluorine-based resins. Adequate adhesive strength cannot be obtained even for polyethylene, polypropylene and the like.
[0003]
Therefore, prior to the adhesion of the difficult-to-adhere adherend with the 2-cyanoacrylate instantaneous adhesive, the surface of the adherend is treated with a primer.
[0004]
Japanese Patent Application Laid-Open No. 6-57218 discloses that at least one of the hydrocarbon groups of the amine represented by the formula R ₃ N (wherein all three R are hydrocarbon groups) has 8 to 24 carbon atoms. A primer for a 2-cyanoacrylate-based instant adhesive having a tertiary amine which is a long-chain hydrocarbon group as an active ingredient is shown.
[0005]
In JP-A-5-140512, R ¹ R ² R ³ N or R ⁴ = NR ⁵ (R ¹ , R ² , R ³ , R ⁴ , R ⁵ are alkyl groups, cycloalkyl groups, aryl groups, etc.) There is a disclosure of a cyanoacrylate-based adhesive primer using an amine compound represented by the formula:
[0006]
Japanese Patent Application Laid-Open No. 62-18485 relating to the applicant's application includes 2,4-lutidine, 3,4-lutidine, 6-amino-2-picoline, 4-dimethylaminopyridine, 2-aminopyridine, 3 A primer for a 2-cyanoacrylate-based instantaneous adhesive comprising a compound selected from the group consisting of -aminopyridine and 1-vinylimidazole or a solvent solution thereof is shown.
[0007]
Similarly, Japanese Patent Application Laid-Open No. 62-18486, filed by the present applicant, discloses 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. A primer for a 2-cyanoacrylate instant adhesive is shown.
[0008]
In Japanese Patent Publication No. 43-5004, in order to give an adhesive force to a synthetic resin body that hardly exhibits adhesion by 2-cyanoacrylate-based instant adhesives such as polyethylene, polypropylene, polyformaldehyde, and polyfluorinated ethylene, A method for treating the surface of these synthetic resin bodies with an inorganic basic substance or an organic basic substance in advance is shown, and examples of the organic basic substance include formamide, dimethylformamide, dimethylacetamide, ethylamine, triethylamine, Examples include monoethanolamine, diethanolamine, piperidine, and pyrroline.
[0009]
In addition, Japanese Patent Publication No. 47-8718, Japanese Patent Publication No. 54-19416, Japanese Patent Publication No. 62-29471, Japanese Patent Publication No. 61-126190, Japanese Patent Publication No. 59-66471, Japanese Patent Publication No. 63-51489. JP-A 63-128090, JP-A 64-66222, and the like also show primers composed of nitrogen-containing compounds similar to the above.
[0010]
[Problems to be solved by the invention]
However, many of the organic basic substances and amine compounds that have been proposed in the past do not improve the adhesive strength, and the relatively preferable primer has some effect on polyethylene and polypropylene. It was only seen.
[0011]
In particular, there are few primers that can obtain a practical adhesive force for silicone rubber, and various silicone rubbers can be used even if they show a slight effect of improving the adhesive force for a specific silicone rubber. On the other hand, it can be said that there is no primer that always provides a sufficient and sufficient adhesive force. For fluorine-based resins such as polytetrafluoroethylene, it has been more difficult to improve the adhesion than in the case of silicone rubber.
[0012]
In this background, the present invention is not limited to difficult-to-adhere adherends such as polyethylene and polypropylene, but to difficult-to-adhere adherends such as silicone rubber and fluorine-based resins that have been conventionally difficult. Provide a primer capable of obtaining a sufficient adhesive force with a 2-cyanoacrylate adhesive, and a method for bonding a hardly adherent adherend with a 2-cyanoacrylate adhesive using the primer. It is intended to provide.
[0013]
[Means for Solving the Problems]
The primer of the present invention is a primer for bonding a hardly adherent adherend with a 2-cyanoacrylate adhesive,
The primer comprises a composition of a silicone oil (a) having a viscosity of 5 cps / 25 ° C. or higher , a trialkylamine (b), and a solvent (c) other than a fluorine-containing solvent and a chlorine-containing solvent ;
The proportion of the silicone oil (a) in the composition is 0.01 to 5% by weight , the proportion of the trialkylamine (b) is 0.005 to 3% by weight, and the balance is the solvent (c) .
It is characterized by.
[0014]
Method of bonding difficult to bond adherends of the invention, to carry out after applying the primer on at least the bond sites of poorly adherent adherends, by applying the 2-cyanoacrylate-based adhesive bonding It is a feature.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described in detail below.
[0016]
<Primer>
As described above, the primer of the present invention comprises a composition of a silicone oil (a) having a viscosity of 5 cps / 25 ° C. or higher , a trialkylamine (b), and a solvent (c) other than a fluorinated solvent and a chlorinated solvent. Become.
[0017]
As the silicone oil (a) , any of dimethyl silicone oil, non-dimethyl silicone oil, and modified silicone is useful. Some commercially available silicone-based oils have various functional groups introduced to improve compatibility and adsorptivity, but in the present invention, 2 to 3 polyfunctional groups are introduced into one molecule. A high degree of modification, such as those or coupling agents, is not necessarily required. Examples of the modified silicone oil among the silicone-based oil (a) are amino-modified silicone, alkyl-modified silicone, aminoalkyl-modified silicone, fatty acid-modified silicone, epoxy-modified silicone, carboxy-modified silicone, polyether-modified silicone, hydroxy-modified silicone, Examples thereof include phenyl-modified silicone and hydrogen-modified silicone. The silicone-based oil (a) may be compatible so long as it does not separate in the primer solvent. The silicone oil (a) may have little or little compatibility with 2-cyanoacrylate. The viscosity of the silicone oil (a) is 5 cps / 25 ° C. or higher for the purpose of the present invention .
[0018]
As trialkylamine (b) , three alkyl groups are methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group (lauryl group). ), Tetradecyl group, hexadecyl group, octadecyl group, eicosyl group, tetracosyl group, etc., or combinations thereof, such as triethylamine, tripropylamine, tributylamine, trilaurylamine, tritetradecylamine, N, Examples thereof include N-dimethyloctylamine, N, N-dimethyldodecylamine, N, N-dimethylhexadecylamine, methylethyldodecylamine, and diethyloctylamine. An example of an important one among these is N, N-dimethylalkylamine having two methyl groups and one alkyl group having 8 or more carbon atoms.
[0019]
As the solvent (c), for the purpose of the present invention, solvents other than fluorine-containing solvents and chlorine-containing solvents, for example, alcohols such as methanol, ethanol, isopropanol, n-propanol, various butanols and cyclohexanol; acetone, methyl ethyl ketone, Ketones such as methyl isobutyl ketone and cyclohexanone; hydrocarbons such as n-hexane, n-heptane, isoheptane, cyclohexane, methylcyclohexane, benzene, toluene, xylene; methyl acetate, ethyl acetate, n-butyl acetate, isobutyl acetate, isoamyl acetate esters and the like; dioxane, diethyl ether, diisopropyl ether, di n- propyl ether; nitrogenated solvent; water and solvents such as, or a mixed solvent consisting of two or more solvents are used.
[0020]
The proportion of each component in the composition is such that the proportion of the silicone oil (a) is 0.01 to 5% by weight (preferably 0.05 to 3% by weight, particularly preferably 0.1 to 1% by weight), and the trialkylamine (b). Is 0.005 to 3% by weight (preferably 0.01 to 2% by weight, particularly preferably 0.05 to 1% by weight) , and the remainder is solvent (c) . Too little silicone oil (a) is insufficient primers effect on poorly adherent adherends tend to insufficient excessive even primers effect of silicone oil (a). If the amount of trialkylamine (b) is too small, the primer effect is insufficient, and if too much trialkylamine (b) is used, the primer effect tends to be insufficient.
[0021]
The solvent (c) is necessary for placing an appropriate amount of the mixture of the silicone oil (a) and the trialkylamine (b) in the primer on the surface of the adherend. The proportion of the solvent (c) is the total of the silicone oil (a) and the trialkylamine (b) , but the primer of the present invention is preferably a thin coating rather than a thick coating. It is desirable that the total amount of the silicone oil (a) and the trialkylamine (b) is 7% by weight or less, particularly 5% by weight or less, and further 3% by weight or less. In this case, the concentration of the total amount of the silicone-based oil (a) and the trialkylamine (b) differs depending on the kind of the hardly-adhesive adherend, so that the hardly-adhesive adherend is a silicone rubber. It is preferable to determine the optimum concentration and composition by conducting preliminary experiments in advance such that the concentration is relatively high, and in the case of polyethylene, polypropylene, and polytetrafluoroethylene, the concentration is lower than that.
[0022]
Other additives and other primer additives may be added to the above-described primer as long as the gist of the present invention is not impaired.
[0023]
<Adhesion method>
The method for adhering a hardly adhesive adherend of the present invention comprises the above-described primer (silicone oil (a) , trialkylamine (b) and solvent (c) at least on the adherend site. After a primer made of the composition is applied, adhesion is performed by applying a 2-cyanoacrylate adhesive.
[0024]
Examples of difficult adhesion adherents include silicone rubber, fluororesin, polyethylene, polypropylene, etc., but these adherends can be used as long as the adhesive strength with 2-cyanoacrylate adhesive cannot be obtained sufficiently. In addition to the body, adherends such as ethylene-propylene terpolymer, polyacetal (polyoxymethylene), polyethylene terephthalate, polybutylene terephthalate, polyamide, and polyvinyl chloride are also used. When different types of materials are bonded, at least one of them may be a hardly adhesive adherend. Adhesion is not only the adhesion between solids, but also after applying and drying the above primer on a solid substrate, applying a 2-cyanoacrylate adhesive, and then applying a liquid material ( For example, a case where a curable resin composition) is applied and cured is also included.
[0025]
As 2-cyanoacrylate adhesive, 2-cyanoacrylate such as alkyl 2-cyanoacrylate, cycloalkyl 2-cyanoacrylate, alkoxyalkyl 2-cyanoacrylate, alkenyl 2-cyanoacrylate, alkynyl 2-cyanoacrylate, etc. is the main ingredient. If necessary, polymerization inhibitors, stabilizers, thickeners, heat resistance imparting agents, plasticizers, colorants, thixotropy improvers, pH adjusters, ethylene carbonate, organic solvents, fillers, synthesis for purposes other than thickening purposes A resin containing resin is used. Among the above, examples of alkyl 2-cyanoacrylate include methyl 2-cyanoacrylate, ethyl 2-cyanoacrylate, various propyl 2-cyanoacrylates, alkyl 2-cyanoacrylates, various butyl 2-cyanoacrylates, and various pentyl 2-cyanoacrylates. Various octyl 2-cyanoacrylates, and examples of alkoxyalkyl 2-cyanoacrylates include ethoxyethyl 2-cyanoacrylate, methoxyethyl 2-cyanoacrylate, methoxyisopropyl 2-cyanoacrylate, and the like.
[0026]
The primer is used after being applied to a hardly adhesive adherend by means of application, potting, spraying, dipping or the like. Usually, the primer-coated surface is dried before the 2-cyanoacrylate adhesive is applied, but there are cases where the adhesive may be applied in an undried wet state.
[0027]
<Action>
The solvent solution of trialkylamine (b) is well known as a primer for 2-cyanoacrylate adhesives, but there are various limitations on the effect of improving adhesion. It is contrary to expectation that the common sense that the silicone-based oil (a) in the primer of the present invention generally acts in a direction that causes a decrease in adhesive strength (improved peelability) rather than an improvement in adhesive strength. On the contrary, it was found that it contributes to a significant increase in adhesive strength.
[0028]
Although it is not necessarily clear why the adhesion strength of the hardly adherent adherend by the 2-cyanoacrylate adhesive is improved by using the primer of the present invention, it is a fact that the adhesion strength is remarkably increased. This is because when the trialkylamine (b) primer is used, the location where the 2-cyanoacrylate adhesive was dropped (the location where the 2-cyanoacrylate adhesive was discharged and adhered) and the location where it diffused to the surroundings. Compared with the phenomenon that the adhesion of the dropped part is inferior to the diffused part when compared, the primer film once coated partially dissolves due to 2-cyanoacrylate, so that part of This may be because the amount of the primer component is reduced. In contrast, in the mixed system of silicone oil (a) and trialkylamine (b) , the primer film once formed is resistant to 2-cyanoacrylate due to the presence of silicone oil (a) . It seems to be.
[0029]
In any case, if the primer of the present invention comprising the composition of the silicone oil (a) , the trialkylamine (b) and the solvent (c) is applied to at least the adherend site of the hardly adherent adherend, By applying a 2-cyanoacrylate adhesive from the above, it is possible not only to adhere to difficult adherents such as polyethylene and polypropylene, but also to adherent adherents such as silicone rubber and fluororesin. Excellent adhesion is obtained, and the adhesion is often so strong that it can lead to substrate failure.
[0030]
【Example】
Next, the present invention will be described in more detail with reference to examples. Hereinafter, “parts” and “%” are expressed on a weight basis.
[0031]
<Preparation of primer>
Examples and Comparative Examples As silicone oil (a) , a 5% concentration solution (a1) of dimethyl silicone oil “SH200” having a viscosity of 5000 cps / 25 ° C. manufactured by Toray Silicone Co., Ltd. dissolved in cyclohexane, manufactured by Toray Silicone Co., Ltd. A 10% concentration solution (a2) of amino modified silicone oil “SF8417” having a viscosity of 1200 cps / 25 ° C. dissolved in n-heptane, a carboxyl modified silicone oil “8418” having a viscosity of 2500 cps / 25 ° C. manufactured by Toray Silicone Co., Ltd. A 10% concentration solution (a3) dissolved in n-pentane and a silicone oil “KF-96L-5cps” (a4) manufactured by Shin-Etsu Chemical Co., Ltd. having a viscosity of 5 cps / 25 ° C. were prepared.
[0032]
As the trialkylamine (b) , N, N-dimethyldodecylamine (b1), N, N-dimethyloctylamine (b2), and trioctylamine (b3) were prepared.
[0033]
As a solvent (c) , 1: 1 mixed solvent (c1), n-heptane (c2) and n-pentane (c3) were prepared in a weight ratio of isopropanol and cyclohexane.
[0034]
Nine types of primers were prepared according to the following formulation.
[0035]
・ Primer formula 1 (Example)
(a1) 10.0 parts (silicone oil , 0.5 parts pure)
(b1) 1.5 parts (N, N-dimethyldodecylamine)
(c1) Residue (isopropanol / cyclohexane)
[0036]
・ Primer formula 2 (Example)
(a2) 4.0 parts (silicone oil , pure part 0.4 parts)
(b1) 0.2 parts (N, N-dimethyldodecylamine)
(c3) Residue (n-pentane)
[0037]
・ Primer prescription 3 (Example)
(a1) 10.0 parts (silicone oil , 0.5 parts pure)
(b3) 0.2 parts (trioctylamine)
(c2) Residue (n-heptane)
[0038]
・ Primer formula 4 (Example)
(a3) 4.0 parts (silicone-based oil , 0.4 parts pure)
(b2) 0.2 parts (N, N-dimethyloctylamine)
(c2) Residue (n-heptane)
[0039]
・ Primer prescription 5 (Example)
(a4) 1.0 parts (silicone oil)
(b1) 1.5 parts (N, N-dimethyldodecylamine)
(c1) Residue (isopropanol / cyclohexane)
[0040]
・ Primer formula 6 (comparative example)
(b1) 1.5 parts (N, N-dimethyldodecylamine)
(c1) Residue (isopropanol / cyclohexane)
[0041]
・ Primer prescription 7 (comparative example)
(b1) 0.2 parts (N, N-dimethyldodecylamine)
(c1) Residue (isopropanol / cyclohexane)
[0042]
・ Primer prescription 8 (comparative example)
(b3) 0.2 parts (trioctylamine)
(c3) Residue (n-pentane)
[0043]
・ Primer prescription 9 (comparative example)
(b2) 0.2 parts (N, N-dimethyloctylamine)
(c2) Residue (n-heptane)
[0044]
<Adhesion test>
As a non-adhesive adherend, a silicone rubber molded body (SR), polytetrafluoroethylene molded body (PTFE), polyethylene molded body (PE), polypropylene molded body (25 mm wide, 100 mm long and 2 mm thick) ( PP) was prepared, and the above primer was brush-applied from the end side of each molded product to a position of about 12.5 mm, and left for a while to dry naturally.
[0045]
10 minutes after applying the primer, a 2-cyanoacrylate adhesive (ethyl 2-cyanoacrylate instantaneous adhesive with a viscosity of 2.5 cps / 25 ° C. manufactured by Alpha Giken Co., Ltd.) is applied to the primer application surface of the molded product A. After applying in a dot shape, the primer application surface of the molded product B was put together and lightly pressed, and left in that state for 10 seconds to prepare a sample for an adhesion test. A number of such samples were prepared, and the adhesion test was performed after leaving for 24 hours.
[0046]
The tensile shear strength was measured using a tensile tester (the numerical value is an average value for five test pieces, and the “#” mark is a base material breakage). The peelability is obtained by observing the situation in the vicinity of the bonded portion when the adherends have opposite sides of the bonded portion and are bent until the portions stick to each other. However, when the silicone rubber molded body (SR) was used, observation was performed by pulling the SR side in the peeling direction. The results are shown in Table 1.
[0047]
[Table 1]

Molded body and primer formulation Tensile shear strength Peelability
Molded body A / Molded body B (kg / cm ² )
Example 1 SR Formulation 1 / SR Formulation 1 6.5 ^# substrate fracture Examples 2 PE Formulation 2 / PE Formulation 2 56.0 ^# folds fall Example 3 PP Formulation 2 / PP Formulation 2 53.0 ^# substrate fracture Examples 4 PTFE formulation 2 / PTFE prescription 2 45.0 ^# Folding Example 5 SR prescription 1 / PTFE prescription 2 6.0 ^# SR material breakage Example 6 SR prescription 1 / PE prescription 3 6.6 ^# SR material breakage Example 7 SR prescription 1 / PP prescription 4 6.1 ^# SR material failure
Example 8 SR prescription 5 / SR prescription 5 6.2 ^# SR material failure
Comparative Example 1 SR Formulation 6 / SR Formulation 6 3.2 Interfacial Fracture Comparison Example 2 PE Formulation 7 / PE Formulation 7 35.0 Interfacial Fracture Comparison Example 3 PP Formulation 8 / SR Formulation 8 2.9 SR Interfacial Breakdown Comparative Example 4 PTFE Formulation 9 / PTFE Formulation 9 3.0 Interface fracture
Comparative Example 5 SR prescription 6 / PP prescription 7 3.1 Interfacial fracture
[0048]
【The invention's effect】
As described in the section of action, the primer of the present invention comprising the composition of silicone oil (a) , trialkylamine (b) and solvent (c) is applied to at least the adherend site of the hardly adherent adherend. Then, by applying a 2-cyanoacrylate adhesive from above, it is difficult to adhere to difficult adherends such as polyethylene and polypropylene, as well as silicone rubber and fluororesin. Excellent adhesion to the adherend is also obtained, and the adhesion is often strong enough to destroy the substrate. Therefore, the primer of the present invention is extremely important for practical use.

Claims (3)

A primer for adhering a difficult-to-adhere adherend with a 2-cyanoacrylate adhesive,
The primer comprises a composition of a silicone oil (a) having a viscosity of 5 cps / 25 ° C. or higher , a trialkylamine (b), and a solvent (c) other than a fluorine-containing solvent and a chlorine-containing solvent ;
The proportion of the silicone oil (a) in the composition is 0.01 to 5% by weight , the proportion of the trialkylamine (b) is 0.005 to 3% by weight, and the balance is the solvent (c) .
A primer characterized by The primer according to claim 1, wherein the trialkylamine (b) is N, N-dimethylalkylamine. A method of adhering an hardly adherent adherend comprising applying the primer of claim 1 to at least an adherend portion of the hardly adherent adherend and then applying a 2-cyanoacrylate adhesive. .