JPH0336070B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an anaerobic adhesive that does not contain peroxides and has excellent adhesive properties. That is, the present invention relates to a high-performance anaerobic adhesive that does not contain peroxides that are irritating to the skin and has excellent adhesion to threaded parts of various materials. Conventionally, there are many anaerobic adhesives that do not harden and remain stable for long periods of time in the presence of air, but when air is blocked by gaps between metals, they harden in a short period of time and exhibit adhesive effects. Utilizing its unique properties, it is widely used in the industrial field to prevent screws from loosening and to fix rings and shafts. Anaerobic adhesives mainly consist of anaerobically polymerizable monomers containing (meth)acrylic groups in their molecules, curing catalysts, curing accelerators, stabilizers, etc.
Most commercially available anaerobic adhesives use organic peroxides as curing catalysts. However, as this organic peroxide is well known, it is highly irritating to the skin and has a pungent odor, so when using anaerobic adhesives containing organic peroxide, it is difficult to consider the working environment. Requires sufficient attention. On the other hand, anaerobic adhesives that do not contain organic peroxides are published in Japanese Patent Publications No. 45-19390, No. 51-597, No. 54-23716,
Unexamined Japanese Patent Publication No. 55-164269, No. 57-105473, No. 57-
No. 105474 and No. 57-165473. All of these have adhesive properties, but
Since it does not contain peroxide, it cannot be said to be fully satisfactory in terms of adhesion speed and adhesion strength. In addition, a system using diazonium salt as a curing catalyst other than organic peroxide (Japanese Patent Publication No. 54-1597)
System using inorganic salt initiator
have also been proposed, but these have problems with solubility and are somewhat unsatisfactory in terms of adhesion. In contrast, the present inventors have proposed
No. 47266, No. 54-28176, and No. 55-1958 proposed an anaerobic adhesive that does not contain peroxide, has fast curing, and has good adhesive properties. These are 2 in the molecule
O.benzoic sulfimide and the following general formula (2) are used as curing catalysts for polyfunctional (meth)acrylates containing more than one (meth)acrylic group. (In the formula, R ₂ and R ₃ represent hydrogen or a methyl group.) It is obtained by adding a salt with an amine, and is used as an anaerobic adhesive that does not contain peroxides. had relatively excellent performance.
However, subsequent studies revealed that among various metals, the adhesion to copper-based metals was extremely poor. Conventional anaerobic adhesives containing a large amount of peroxide have the drawbacks of skin irritation and bad odor, as mentioned above, but they cure rather quickly on copper-based metals. In anaerobic adhesives that do not contain copper, copper exhibits a polymerization inhibiting effect, and therefore adhesion is significantly inhibited. The present inventors conducted research to improve the invention by the present inventors with the aim of improving the adhesion to copper-based metals and obtaining a peroxide-free anaerobic adhesive with even better performance. As a result, in the composition of the invention of the present inventors, polyfunctional (meth)acrylate containing two or more (meth)acrylic groups in the molecule was mainly used as the anaerobically polymerizable monomer. However, a part of it is expressed as the following general formula (1) (In the formula, R is hydrogen or a methyl group, _R1 is an alkylene group having 2 to 4 carbon atoms, and n is an integer of 1 to 8.) It was discovered that it can also be bonded to copper-based metals. In the system of (meth)acrylate alone represented by general formula (1), adhesion is extremely poor not only to copper-based metals but also to other metals.
It is surprising that when used in combination with acrylate, on the contrary, the adhesion is improved. Furthermore, the inventors discovered that the adhesion was further improved by adding a small amount of an azo polymerization initiator to this system, leading to the present invention. That is, the present invention comprises (a) a hydroxyl group-containing anaerobically polymerizable monomer represented by the general formula (1), and an anaerobically polymerizable monomer containing two or more (meth)acrylic groups in the molecule; 100 parts by weight of any mixture of (b) 0.benzoic sulfimide and the general formula
This invention relates to an anaerobic adhesive containing 0.2 to 10 parts by weight of a salt with an amine represented by (2) and 0.01 to 10 parts by weight of (c) an azo polymerization initiator. Examples of hydroxyl group-containing (meth)acrylates represented by general formula (1) include hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, polyethylene glycol mono(meth)acrylate, and polypropylene glycol mono(meth)acrylate. Meta)
Examples include acrylate. These hydroxyl group-containing (meth)acrylates can also be anaerobically cured by adding a salt of O.benzoic sulfimide and an amine represented by the general formula (2) (hereinafter abbreviated as S.amine salt). It has extremely poor adhesion to copper-based metals as well as other metals such as iron. However, polyfunctional (meth)acrylates containing two or more (meth)acrylates in the molecule
When mixed with acrylate, the synergistic effect of both improves adhesion, especially to copper-based metals. Examples of anaerobically polymerizable monomers containing two or more (meth)acrylic groups in the molecule include ethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, Poly(meth)acrylates of polyhydric alcohols such as glycerin tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth)acrylate, and di(meth)acrylate of bisphenol A alkylene oxide adducts. , urethane poly(meth)acrylates and polyester(meth)acrylates which are addition reaction products of the compound of the general formula (1) and a polyisocyanate compound containing two or more isocyanate groups in the molecule. It will be done. As mentioned above, these polyfunctional (meth)acrylates exhibit good adhesion to various materials by adding S/amine salts, but their adhesion to copper-based metals is extremely poor. By mixing the monomers in (1), this drawback can be overcome. Particularly preferred is urethane poly(meth)acrylate. The S.amine salt can be easily synthesized by the method described in the above-mentioned patent by the present inventors. In addition, O.benzoic sulfimide and the general formula
The amines represented by (2) are added in equal moles to the anaerobically polymerizable monomers that are the components of the present invention, and
Although it can also be obtained by a heating reaction at 100°C, it is better to add the salt isolated in the form of a salt by the former method to obtain an anaerobic adhesive with better physical properties. The amount of S.amine salt added is preferably 0.2 to 10 parts by weight per 100 parts by weight of the anaerobically polymerizable monomer.
It is 1.0 to 3.0 parts by weight. The amine represented by the general formula (2) in the S.amine salt is a 1,2,3,4-tetrahydro derivative of quinoline, and examples include 1,2,3,4-tetrahydroquinoline, 1,2 ,3,4-tetrahydroquinaldine,
Examples include 6-methyl-1,2,3,4-tetrahydroquinoline. Even if an aromatic tertiary amine is used in addition to these heterocyclic secondary amines, the composition of the present invention can be bonded to various materials, but the storage stability is somewhat unsatisfactory. be. Examples of the azo polymerization initiator include 2-tert-butyl azo-2-cyanopropane, 1-
Examples include t-butylazo-1-cyanocyclohexane, 2-t-butylazo-2-cyanobutane, azobisisobutyronitrile, and t-t-butylazoformamide.
Particularly preferred are the first three, which are liquid at room temperature. The amount added is 10 parts by weight per 100 parts by weight of the polymerizable monomer.
It is not more than 0.1 to 2 parts by weight, preferably 0.1 to 2 parts by weight.
These azo polymerization initiators are known as blowing agents and radical polymerization catalysts, but when used as curing catalysts for anaerobic adhesives, almost no effect has been observed. The inventors of the present invention investigated the addition of the compound to the composition of the present invention, and found that the adhesion to various materials, particularly copper-based metals, was further improved. The above is the main structure of the present invention, but it is also possible to add the following additives for the purpose of further increasing the commercial value. Namely, for the purpose of increasing adhesive strength, polymerizable acidic phosphoric acid ester, polymerizable or copolymerizable sulfonic acid, polyphosphoric acid for the purpose of increasing adhesive strength and storage stability, and various types of radical polymerization for the purpose of increasing storage stability. Inhibitors, metal chelating agents, amine salts of organic acids, soluble polymers for the purpose of adjusting viscosity, thixotropic agents, other plasticizers, photosensitizers, etc. As described above, the present invention provides an anaerobic adhesive that has good adhesion to various materials without using a peroxide initiator that is highly irritating to the skin.
This will greatly contribute to the development of this industry. Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples. The performance test for each adhesive is JAI-6.
-1979, as follows. Γ Set Time Apply adhesive on the thread of the M10 bolt,
The nut was screwed in and left at 23°C without applying any tightening torque, and the time from the start of adhesion until the nut could no longer be moved by hand was measured, which was defined as the set time. The shorter the set time, the faster the adhesion speed. ΓReturn torque strength The same glued bolts and nuts as above were further heated to 23°C for 24
After leaving it for a while, the breaking torque and escape torque strength were measured using a torque wrench. Breaking torque strength indicates the torque at which the bond first breaks when loosening a bonded bolt or nut by rotation, and escape torque indicates the torque at the subsequent 1/4, 1/2, 3/4, and 1 rotation. The average value of each torque was taken as the average value of each torque. Γ Storage Stability Only 1/2 amount of adhesive was placed in a 100 ml polyethylene container, and the container was left in a hot air dryer at 50° C., and the presence or absence of thickening or gelation of the adhesive was observed. The adhesive is stable at room temperature for more than one year without significant changes under these conditions. Example 1, Comparative Example 1 Tetraethylene glycol dimethacrylate 60
and 40 parts of hydroxypropyl methacrylate to a mixture of 1, 2,
3,4-tetrahydroquinoline salt (hereinafter referred to as STQ)
Add 1.5 parts of salt) and 0.005 parts of oxalic acid,
An adhesive was prepared by heating and melting at 60°C for 15 minutes. The obtained adhesive was divided into two equal parts, one was left as is (Adhesive No. 1), and the other was added with 1-tertiarybutylazo-1-cyanocyclohexane (TBA-96 manufactured by Nippon Hydrazine Kogyo Co., Ltd.). Adhesiveness and storage stability to bolts and nuts of iron, brass, and unichromate were measured by adding 0.5% by weight (Adhesive No. 2). For comparison, the composition of only tetraethylene glycol dimethacrylate and STQ salt (adhesive
No. 3) was also implemented. The results are shown in Table 1.
As is clear from Table 1, when the anaerobically polymerizable monomer is tetraethylene glycol dimethacrylate alone, it does not adhere to brass, which is a copper-based metal, whereas in the case of the example where the anaerobically polymerizable monomer is a mixed system with hydroxypropyl methacrylate, It is possible to adhere to brass, and the addition of an azo polymerization initiator makes the adhesion even better.

[Table] Example 2, Comparative Example 2 Trimethylolpropane trimethacrylate 60
S. amine salt shown in Table 2 was added as a curing catalyst to a mixture of 40 parts of hydroxypropyl methacrylate and
Add 1.5 parts and further add 0.03 parts of polyphosphoric acid.
After heating and dissolving at 60° C. for 15 minutes, the mixture was cooled to room temperature, and 0.5 part of 2-tert-butylazo-2-cyanopropane (TBA-79, manufactured by Nippon Hydrazine Kogyo Co., Ltd.) was added to prepare an adhesive. Table 2 shows the results of measuring the storage stability and adhesion to iron and brass bolts and nuts of the obtained adhesive in the same manner as in Example 1.
Shown below. For comparison, the physical properties were also measured for compositions using only 1.5 parts of O.benzoic sulfimide and 1.5 parts of 1,2,3,4-tetrahydroquinoline. As is clear from Table 2, all systems other than those using S.amine salt had significantly poor adhesion.

[Table] Example 3, Comparative Example 3 100 parts of a mixture of urethane polymethacrylate and other anaerobically polymerizable monomers obtained by addition reaction of toluene diisocyanate and hydroxypropyl methacrylate at a molar ratio of 1:2 using a conventional method. ,
An adhesive was prepared in the same manner as in Example 1 from 1.5 parts of STQ salt, 0.03 parts of polyphosphoric acid, 0.005 parts of ethylenediamine salt of methacrylic acid, and 0.5 parts of 2-tertiarybutyl azo-2-cyanobutane (TBA82 manufactured by Nippon Hydrazine Kogyo Co., Ltd.). It was prepared and its physical properties were measured. For comparison, a system with the same composition but using only hydroxypropyl methacrylate without using the urethane polymethacrylate was also tested. The results are shown in Table 3. When hydroxypropyl methacrylate was used alone, it did not adhere to brass bolts and had poor adhesion to iron bolts.

【table】

[Table] Example 4 Same urethane polymethacrylate 50 as Example 3
1.5 parts of STQ salt, 0.03 part of polyphosphoric acid and 0.005 part of ethylenediamine salt of methacrylic acid are added to a mixture of 50 parts of hydroxypropyl methacrylate;
An adhesive was obtained by heating and melting at 60°C for 15 minutes. Divide the resulting adhesive into two equal parts, leaving one half intact (glue
No.13) On the other hand, 2-tert-butylazo-2
- Adding 0.5 part of cyanopropane (Adhesive No. 14),
Table 4 shows the results of measuring the adhesion of various materials to bolts and nuts. The system containing an azo polymerization initiator showed better values for brass, chromate treatment, chrome plating, stainless steel, etc.

【table】

【table】

Claims (1)

[Claims] 1 (a) General formula (1) (In the formula, R is hydrogen or a methyl group, R ₁ is an alkylene group having 2 to 4 carbon atoms, and n is an integer of 1 to 8.) 100 parts by weight of any mixture with an anaerobically polymerizable monomer containing at least one (meth)acrylic group, and (b) 0.benzoitux sulfimide with the following general formula:
(2) (In the formula, R ₂ and R ₃ represent hydrogen or a methyl group.)
Anaerobic adhesive 2 consisting of 0.2 to 10 parts by weight of a salt with an amine represented by and (c) 0.01 to 10 parts by weight of an azo polymerization initiator Anaerobic polymerization containing two or more (meth)acrylic groups in the molecule A patent characterized in that the monomer is a urethane poly(meth)acrylate obtained by an addition reaction between the compound of general formula (1) and a compound having two or more isocyanate groups in the molecule. The anaerobic adhesive according to claim 1.