JPH0133483B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a curing accelerator solution for accelerating the curing of a (meth)acrylic curable composition containing a radical polymerization initiator. In particular, the present invention provides a high performance curing accelerator solution suitable for anaerobic adhesives and second generation acrylic adhesives. Anaerobic adhesives are stable and do not harden for long periods of time as long as they are in contact with air, but once they are placed between two metal surfaces and the air is blocked, they harden in a short period of time. It is widely used to prevent loosening of pipes, seal piping parts, etc. Usually, it is used as a single component, but when fast curing is required in line work or when adhering difficult-to-adhesive materials such as plating materials, it cannot fully demonstrate its function, so a curing accelerator is used. This drawback is compensated for as a two-component type by using a primer containing . The second generation acrylic adhesive is made of (meth)acrylate monomer, elastomer, organic peroxide, etc.
It is a fast-curing two-component adhesive consisting of liquid B and a curing accelerator, and has been attracting a lot of attention in recent years due to its excellent workability and adhesive performance. Most of the curing accelerators in these are anaerobic adhesives or reducing agents that can form redox with organic peroxides contained in liquid A of second generation acrylic adhesives. , mercaptans, thiourea, ascorbic acid, metal chelate compounds, tertiary amines, etc.
All of them are publicly known. As mentioned above, the use of such a reducing agent makes it possible to make the (meth)acrylic curable composition quick-curing, but in recent years, as assembly processes have become faster, further improvements in performance have been desired. It is rare. That is, the curing speed is faster, the adhesion is not affected by the surface of the adherend and it hardens quickly to any material, and there is no bad odor. As a result of intensive research into curing accelerators that meet this purpose, the present inventors have found that a reducing agent system consisting of a combination of a copper or vanadium chelate compound and 0-benzoic sulfimide or arylsulfonyl hydrazide has extremely good performance. This discovery led to the present invention. That is, the present invention relates to a curing accelerator solution for a (meth)acrylic curable composition obtained by dissolving the following (1) and (2) in an organic solvent. (1) Copper and/or vanadium chelate compound (2) 0-benzoic sulfimide and/or arylsulfonyl hydrazide Examples of using metal chelate compounds as components of curing accelerators include Japanese Patent Publications No. 44-31830 and No. 49 ―
21093, 49-48678, and JP-A-48-21786, but they are insufficient in terms of adhesion speed. Furthermore, in Japanese Patent Publication No. 39-29195, the curing speed of unsaturated polyester resin is improved by using a curing accelerator consisting of a combination of a vanadium compound and mainly mercaptans;
No. 55-17041 improves the adhesion speed of a second generation acrylic adhesive by combining a metal chelate compound and thiourea. In these inventions, the curing speed is considerably improved compared to the metal chelate compound alone, but when mercaptan or thiourea is used, there is a strong odor, there are problems in the working environment, and there are problems with the adherend material. Depending on the type of metal, the adhesion speed and adhesion strength tend to be poor, and it cannot be said that the adhesive has sufficient performance for practical use. On the other hand, 0-benzoic sulfimide and arylsulfonyl hydrazide were
As described in 6545 and Japanese Patent Application Laid-Open No. 117789/1989, it is mainly used as an adhesion promoter when added to anaerobic adhesives when used as a single component. The present inventors have discovered that organic solvent solutions of 0-benzoic sulfimide and arylsulfonyl hydrazide, which are used as additives in anaerobic adhesives, and copper or vanadium chelate compounds among metal chelate compounds have a synergistic effect. It has been found that it exhibits an extremely excellent ability to accelerate curing. That is, 0
- Benzoic sulfimide and arylsulfonyl hydrazide alone have a very weak curing accelerating ability, and copper or vanadium chelate compounds alone have an accelerating effect, but it is not sufficient. However, when both are mixed together, they exhibit a significantly superior curing accelerating effect compared to when either is used alone. As the copper or vanadium chelate compound, β-diketone or ketoester chelate compounds are suitable, such as copper acetylacetonate, copper acetylacetonate,
Examples include vanadium acetylacetonate. The amount used is 0.01 to 5% by weight, preferably 0.1 to 2% by weight in the curing accelerator solution. Examples of the arylsulfonyl hydrazide include benzenesulfonyl hydrazide and toluenesulfonyl hydrazide. The amount of 0-benzoic sulfimide and arylsulfonyl hydrazide used is 0.01 to 7% by weight, preferably 0.2 to 3% by weight in the curing accelerator solution. Suitable solvents for dissolving these curing accelerators include low-boiling organic solvents such as trichloroethane, trichloroethylene, chloroform, methanol, ethanol, and isopropanol, and polymerizable (meth)acrylate monomers. The (meth)acrylic curable composition whose curing is promoted by the curing accelerator solution of the present invention as described above may be composed of a radical polymerization initiator and a monomer containing a (meth)acrylic group. There is no particular difference. Examples of radical polymerization initiators include amine salts of 0-benzoic sulfimide and organic peroxides. The amine salt of 0-benzoic sulfimide was disclosed by the present inventors as a curing agent for anaerobic adhesives in Japanese Patent Publication No. 53-47266, etc., and this amine salt is different from organic peroxides. It has been difficult to accelerate the curing of adhesives using curing agents using conventional redox systems, but this has become possible by using the curing accelerator solution of the present invention.
Organic peroxides include hydroperoxide,
Examples include peroxy esters and ketone peroxides. In addition, monomers containing (meth)acrylic groups include methyl (meth)acrylate, cyclohexyl (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, 2-hydroxy-3-phenyl Mono(meth)acrylates such as oxypropyl(meth)acrylate, ethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, polyethylene glycol di(meth)acrylate, bisphenol A
Examples include polyvalent (meth)acrylates such as di(meth)acrylates of alkylene oxide adducts, liquid rubber end-ended (meth)acrylates, epoxy(meth)acrylates, and urethane poly(meth)acrylates. The above is the structure of the present invention. Depending on the purpose, soluble polymers and thixotropic agents are used to adjust viscosity, elastomers are used to impart toughness to the cured product, and polymerizable acidic phosphoric acid is used to increase adhesive strength. It is also possible to add an appropriate amount of ester, polyphosphoric acid, etc. Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples. However, all parts indicate parts by weight. [Example 1-1, Comparative Example 1-1] An anaerobic adhesive was prepared by adding 0.5 part of cumene hydroperoxide to 50 parts of dimethacrylate, which is a 3-mol adduct of bisphenol A with ethylene oxide, and 50 parts of hydroxypropyl methacrylate. Prepared. Furthermore, a curing accelerator solution was prepared by adding and dissolving predetermined amounts of various curing accelerators shown in Table 1 in a mixed solvent consisting of 99 parts of trichloroethane and 1 part of hydroxypropyl methacrylate. Next, apply the obtained hardening accelerator solution to the thread of a chromate bolt (M10), which is a difficult-to-adhesive material, and after drying, apply a few drops of the anaerobic adhesive and screw in the same type of nut.
The set time and return torque after 24 hours were measured. The measurement method is as follows. Set time: After the nut was screwed in, the time until the nut could no longer be loosened with fingers due to the start of hardening was measured and was defined as the set time. Resetting torque: After leaving the glued bolts and nuts for 24 hours, loosen them with a torque wrench to 1/4, 1/2, 3/4,
The average value of each torque during one rotation was taken as the return torque. In addition, for comparison, the case where bonding was performed using an anaerobic adhesive alone and the case where a curing accelerator solution having a single curing accelerator component was used were also conducted.

[Example 1-2, Comparative Example 1-2]

Table 2 shows the results of bonding M10 bolts and nuts made of various materials other than chromate using the anaerobic adhesive obtained in Example 1-1 and the curing accelerator solution of Example 1-1, No. 3. . For comparison, Comparative Example 1-1,
Table 2 also shows a case where the curing accelerator solution No. 5 was used as a comparative example.

[Example 1-3, Comparative Example 1-3]

Hydroxypropyl methacrylate and 2,4-
Tolylene diisocyanate in a ratio of 2:1 according to the usual method.
50 parts of urethane polymethacrylate obtained by addition reaction at a molar ratio of 50 parts of hydroxypropyl methacrylate, 1.5 parts of various amine salts shown in Table 3 of 0-benzoic sulfimide as a radical polymerization initiator, and 0.02 part of polyphosphoric acid. An anaerobic adhesive containing no organic peroxide was prepared by mixing and dissolving the following. Next, a chromate bolt was adhered to this using the curing accelerator solution of Example 1-1, No. 3 in the same manner as in Example 1-1, and the physical properties were measured. The results are shown in Table 3. For comparison, cases in which no curing accelerator solution was used are also shown as comparative examples. Although the adhesive is anaerobic and does not contain organic peroxides, it is clear that the use of the curing accelerator solution of the present invention results in significantly faster curing.

【table】

[Example 1-4, Comparative Example 1-4]

45 parts of methyl methacrylate, 2-hydroxy-
35 parts of 3-phenyloxypropyl acrylate,
Nitrile rubber (Nipole 1072 manufactured by Nippon Zeon) 15
part, 0.1 part of polyphosphoric acid and 5 parts of cumene hydroperoxide to form a second generation acrylic adhesive A.
A liquid was prepared. Impact peel strength was then measured according to ASTM.D950-54. That is, at 23℃
The hardening accelerator solution of Example 1-1, No. 3 was applied to one of the impact peeling test pieces manufactured from SS-41 general structural steel material, and then dried, and the other test piece was coated with the second impact peeling test piece obtained above. Applied with generation acrylic adhesive. Next, the two were bonded together by rubbing them together, and the time until the two could no longer be peeled off by hand (set time) and the impact peel strength after 24 hours were measured. For comparison, a system using the curing accelerator solution of Comparative Example 1-1, No. 5 was also tested. The results are shown in Table 4.

[Example 2, Comparative Example 2]

Using a solution consisting of 100 parts of methanol and 0.02 parts of polyphosphoric acid as a solvent, and varying the amounts of panadium acetylacetonate and toluenesulfonyl hydrazide, the adhesive properties for the anaerobic adhesive of Example 1-1 were compared to those of Example 1-1. Table 5 shows the results of similar measurements. As is clear from Table 5, when the two coexist, the set time becomes shorter and the adhesive strength increases significantly.

【table】

Claims (1)

[Scope of Claims] 1. A curing accelerator solution for a (meth)acrylic curable composition obtained by dissolving the following (1) and (2) in an organic solvent. (1) Copper and/or vanadium chelate compound (2) 0-benzoic sulfimide and/or arylsulfonyl hydrazide