JPH0244346B2 - SETSUCHAKUZAISOSEIBUTSU - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a one-component structural adhesive composition that adheres metals in an extremely short time at room temperature and has excellent surface adhesion strength and oil surface adhesion. In other words, the present invention has fast hardening properties that allow metal-to-metal surface adhesion to adhere within approximately 10 minutes and reach practical strength within several hours, surface adhesion strength against tension, splitting, impact, etc., and resistance to parts contaminated with oil. The present invention provides a one-component adhesive composition with excellent adhesive properties. Epoxy resins have traditionally been common as solvent-free structural adhesives and are used in large quantities due to their excellent surface adhesion strength, but the drawback of two-component adhesives is that they must be weighed and mixed thoroughly just before use. After mixing, it needs to be used up within a certain period of time, and there is also the problem of skin damage caused by the hardening agent. On the other hand, the one-component type does not require mixing and is easy to work with, but it requires a high temperature of 120°C or higher for curing and is said to have problems with shelf life. In contrast, acrylic structural adhesives have recently come into use. This is a non-mixable two-component type, in which a primer containing a curing accelerator is applied to the surface of one adherend immediately before bonding, and then a base agent containing an organic peroxide is applied to the other surface, and then both It is characterized by its good workability as it does not require mixing as it is fixed by rubbing the two together, it can be fixed in a short time at room temperature, and it has an adhesive strength comparable to that of epoxy resin. Disadvantages of this type include that although mixing is no longer necessary, it is still a two-component system and the bonding process requires two steps, and that organic peroxides and curing accelerators are highly irritating. On the other hand, the present inventors have proposed the general formula (2) in Japanese Patent Publication No. 47-29490. (However, in the formula, R ₂ is hydrogen or a methyl group, R ₃ is an alkylene group having 2 to 4 carbon atoms or a halogenated alkylene group, m is an integer of 1 to 8, and n is 1 or 2.) He proposed a curable composition containing a polymerizable phosphoric acid ester, and suggested that it was also useful for adhesives.
47266, 54-28176 and 55-1958, o-benzoic sulfimide and the general formula
(3) (However, in the formula, R ₄ and R ₅ represent hydrogen or methyl groups.) Using a mixture with an amine represented by the formula or its salt, it does not contain organic peroxides that cause irritation, and is a one-part product. We have found a composition that cures fairly quickly as a permanent adhesive. However, although the latter invention shows excellent performance in adhesion and sealing of fitting parts such as threaded parts, the adhesive strength is insufficient when used for structural adhesion between flat surfaces. As a result of further investigation, we added a very small amount of the polymerizable phosphoric acid ester represented by general formula (2) or its salt, which is a component of the former invention, to the composition of the latter invention, and added a small amount of organic peroxide. It was discovered that by adding an appropriate amount of water, a structural adhesive that is one-component, hardens rapidly at room temperature, and has excellent surface adhesive strength and oil surface adhesion was obtained, leading to the present invention. . There are many examples of using polymerizable phosphate esters in adhesives, but examples of adding them to one-component acrylic adhesives include JP-A-51-132234 and JP-A-57-
There is No. 83572. Both of these have different compositions from the present invention, and the present invention has significantly better performance as an adhesive. That is, the composition of JP-A-51-132234 requires a high temperature of 100°C or more for adhesion.
The final strength is also inferior to that of the present invention, especially in impact strength. Moreover, when this is bonded at room temperature, the bonding speed is extremely slow and cannot be said to be practical. Although the composition of JP-A-57-83572 allows bonding at room temperature, it is still significantly inferior in both bonding speed and bonding strength when compared to the composition of the present invention. Hereinafter, the compositional characteristics and performance of the present invention will be explained in detail. The present invention is based on the general formula (1) (However, in the formula, R ₁ is an alkylene group having 2 to 4 carbon atoms, and 1 is an integer of 1 to 8.) 90 to 20% by weight of a hydroxyl group-containing polymerizable methacrylic acid ester and a methacrylic group in the molecule. The present invention relates to an adhesive composition prepared by adding 100 parts by weight of a mixture of 10 to 80% by weight of a polymerizable methacrylic ester having two or more of the following, a to d below, and a polymerization inhibitor if necessary. a General formula (2) (However, in the formula, R ₂ is hydrogen or a methyl group, R ₃ is an alkylene group having 2 to 4 carbon atoms or a halogenated alkylene group, m is an integer of 1 to 8, and n is 1 or 2.) Polymerizable phosphate ester or salt thereof
0.005-0.5 parts by weight. b o-benzoic sulfimide and general formula (3) (However, in the formula, R ₄ and R ₅ represent hydrogen or a methyl group.) 0.5 to 5.0 parts by weight of an equimolar mixture with an amine or indoline, or a salt thereof. c Organic peroxide 0.005-1.0 parts by weight. d Water 0.2-2.5 parts by weight. The monomer represented by general formula (1) is a monomethacrylate of alkylene glycol or polyalkylene glycol, and is an essential monomer in order to obtain strong surface adhesion strength and oil surface adhesion in the composition of the present invention. . Further, in order to uniformly dissolve water, 20% by weight or more of the monomer composition is required.
Examples include hydroxyethyl methacrylate,
Examples include hydroxypropyl methacrylate, hydroxybutyl methacrylate, polyethylene glycol monomethacrylate, polypropylene glycol monomethacrylate, and the like. In the present invention, polymerizable methacrylic acid esters having two or more methacrylic groups in the molecule have water resistance,
Used to further improve heat resistance and adhesion. Examples include dimethacrylate of polyalkylene glycol, polymethacrylate of polyhydric alcohol, dimethacrylate of alkylene oxide adduct of bisphenol A, polyester methacrylate obtained by esterifying dibasic acid with glycol and methacrylic acid, and liquid rubber. Terminal methacrylate compound, compound of general formula (1), glycol and polyisocyanate compound with hydroxyl group
Examples include urethane polymethacrylate obtained by addition reaction so that NCO groups are approximately equivalent. Among them, dimethacrylates which are alkylene oxide adducts of bisphenol A, in which the amount of alkylene oxide added is 3 moles or less per mole of bisphenol A, and urethane polymethacrylates exhibit excellent overall adhesive performance. Also,
Acrylates can be used instead of these monomers, but they are not preferred in terms of skin irritation and bad odor. In the present invention, a small amount of the polymerizable phosphoric acid ester represented by the general formula (2) or its salt is added for the purpose of greatly improving surface adhesion strength and oil surface adhesion. This polymerizable phosphoric acid ester or its salt is a polymerizable methacrylic acid ester having a specific composition as described above, and o-benzoic sulfimide and a general formula (3).
An equimolar mixture with amine or indoline represented by, or a salt thereof (hereinafter abbreviated as S-amine salt),
It shows a remarkable effect in increasing adhesive strength in the coexistence of organic peroxide and water. That is,
By adding polymerizable phosphate ester or its salt, the impact strength etc. is several times higher than when it is not added, and the adhesion to oil surfaces is also improved, making it comparable to epoxy resin even though it has one-component quick hardening. Adhesive strength can be obtained. Examples of the polymerizable phosphoric acid ester of general formula (2) include methacryloyloxyethyl acid phosphate, bis(methacryloyloxyethyl) acid phosphate, methacryloyloxypropyl acid phosphate, and bis(methacryloyloxypropyl) Examples include acid phosphate, methacryloyloxychloropropyl acid phosphate, bis(methacryloyloxychloropropyl) acid phosphate, and acryloyloxy types thereof, which are used alone or in a mixed system. These can be obtained by various synthetic methods, but it is generally advantageous to obtain them by addition reaction of hydroxyalkyl methacrylates and phosphorus pentoxide. For example, by adding hydroxychloropropyl methacrylate and phosphorus pentoxide in a 3:1 molar ratio at room temperature to 90°C in the absence of a solvent, n=
Equimolar mixtures of 1 and 2 are easily obtained. This mixture can be added directly without separation. Further, these salts can be produced by a conventional method using a polymerizable methacrylic acid ester represented by the general formula (2) and a neutralizing agent. Examples of neutralizing agents include hydroxides and carbonates of alkali metals such as sodium and potassium, oxides, hydroxides, carbonates, ammonia, trimethylamine, triethylamine, and alkaline earth metals such as magnesium, calcium, and barium. Examples include amines such as propylamine, tributylamine, methylamine, ethylamine, propylamine, butylamine, ethylenediamine, trimethylenediamine, diethylenediamine, and hexamethylenediamine.
Note that other metal compounds can also be used as neutralizing agents, but they have some problems in terms of toxicity, storage stability, etc. Among the above, in the present invention, the Na salt, K salt and ammonium salt of polymerizable phosphoric acid ester are particularly good in terms of adhesive strength. Furthermore, it has been found in the present invention that ammonium salts and amine salts not only contribute to adhesive strength but also significantly improve storage stability of the composition. Therefore, when ammonium salts and amine salts are used, it is advantageous that they can be stored for a long period of time without using other polymerization inhibitors. The amount of these polymerizable phosphoric acid esters or their salts added is 0.005 to 0.5 parts by weight, preferably 0.1 to 0.5 parts by weight, based on 100 weight parts of the polymerizable methacrylic ester monomers.
It is 0.3 parts by weight. If the number exceeds this range,
On the contrary, if the adhesive strength decreases, it will not be possible to obtain an adhesive strength that meets the purpose of the present invention. The S-amine salt can be easily obtained by addition reacting o-benzoic sulfimide with the amine or indoline represented by the general formula (3) in an inert solvent. The amount added is 0.5 to 5.0 parts by weight per 100 parts by weight of the polymerizable methacrylic acid ester monomer; if it exceeds 5 parts by weight, no improvement in performance is observed, and if it is less than 0.5 parts by weight, the adhesive performance deteriorates. .
In the present invention, the S-amine salt has a strong curing accelerating effect, and therefore the amount of organic peroxide used as a curing agent can be reduced to an extremely small amount. Excellent performance can also be obtained by adding approximately equimolar amounts of o-benzoic sulfimide and the amine of general formula (3) or indoline to the above composition without forming it into a salt form. The salt form is slightly more advantageous in terms of adhesive strength and amine odor. still,
The amine represented by the general formula (3) includes 1, 2,
3,4-tetrahydroquinoline, 6-methyl
1,2,3,4-tetrahydroquinoline, 1,
Examples include 2,3,4-tetrahydroquinaldine. Examples of organic peroxides include hydroperoxides, ketone peroxides, dialkyl peroxides, diacyl peroxides, and peroxy esters, but hydroperoxides are particularly preferred in terms of adhesion speed, stability, etc. type is optimal. Examples of the hydroperoxide include t-butyl hydroperoxide, p-menthane hydroperoxide, cumene hydroperoxide, and diisopropylbenzene hydroperoxide. The amount added is based on 100 parts by weight of polymerizable methacrylic acid ester monomer.
The amount is 0.005 to 1.0 parts by weight, preferably 0.01 to 0.5 parts by weight. In the present invention, addition of such a very small amount is sufficient, and there is no need to add a large amount of 2% or more as in conventional acrylic adhesives. If the amount of organic peroxide added exceeds 2%, not only will it have a strong odor, but it will also be highly irritating to human skin, so from the standpoint of occupational hygiene, it is desirable to keep it as small as possible, especially below 1%. . However, when the amount of organic peroxide added is reduced, the adhesion speed and adhesion strength deteriorate in conventional compositions, and no compositions have been found that exhibit good adhesion even with a small amount of 0.1% or less as in the present invention. Water is an essential component in the present invention to significantly increase the adhesion speed and to increase surface adhesion strength.
0.2 to 2.5 parts by weight, preferably 0.5 to 2.5 parts by weight
2.0 parts by weight is added. The adhesion speed is significantly increased by adding water, and even though it is a one-liquid product, it can be fixed in minutes, reaching final strength in a few hours, and unlike conventional acrylic structural adhesives. There is no need to apply a highly irritating amine-based curing accelerator as a primer. Examples of polymerization inhibitors that may be added as necessary in the present invention include known radical polymerization inhibitors such as hydroquinone, benzoquinone, and hydroquinone monomethyl ether. Amine salts are particularly preferred. As an example of using amine salts of organic acids in anaerobic curing compositions, there is
-47492 was found to exhibit a significant gel stabilizing effect when added to the composition of the present invention. Preferred amine salts of organic acids include diethylamine salts, elendiamine salts, and 2-ethylhexylamine salts of methacrylic acid or acetic acid, and the amount added is 0.001 to 100 parts by weight of the polymerizable methacrylic acid ester monomer. 10 parts, preferably 0.01 to 5 parts. In addition, as mentioned above, the general formula (2)
When the ammonium salt or amine salt of the polymerizable phosphoric acid ester shown in the formula is used, since it itself acts as a strong gelation stabilizer, there is no need to add another polymerization inhibitor. It is also possible to further add appropriate amounts of colorants, thickeners, thixotropic agents, plasticizers, organic and inorganic fillers, etc. to the composition of the present invention. As mentioned above, although the adhesive obtained by the present invention is one-component and solvent-free, it cures very quickly, does not require a primer, and has surface adhesion strength comparable to that of epoxy resin. Furthermore, it has excellent adhesion to oil surfaces, and can be said to be a major improvement over the drawbacks of conventional adhesives. Next, the present invention will be explained in more detail with reference to Examples, Comparative Examples, and Reference Examples. However, all parts indicate parts by weight. Example 1 Dimethacrylate of 50 parts of 2-hydroxypropyl methacrylate and 2.6 moles of ethylene oxide adduct (average addition amount) of bisphenol A (NK ester BPE-2.6, manufactured by Shin-Nakamura Chemical Co., Ltd.)
(abbreviated as BPE2.6) and 50 parts of acrylic polymer as a thickener (Dyanal BR-Mitsubishi Rayon).
75) was added and dissolved by heating at 80°C for 2 hours.
Then, as an S-amine salt, a salt of o-benzoic sulfimide and 1,2,3,4-tetrahydroquinoline (in ethanol at 40°C, o-benzoic sulfimide and 1,2,3,4- 1.5 parts of tetrahydroquinoline (hereinafter abbreviated as STQ salt) were added and dissolved by heating for 10 minutes. After cooling to room temperature, 0.5 parts of cumene hydroperoxide and 1.5 parts of water was added and dissolved with stirring. 0.1 part of various polymerizable phosphate esters were added to this system, and the physical properties were measured. The results are shown in the table. However, the physical properties were measured using the following method. Measurement of Γ bond strength Tensile shear strength: ASTM, D1002-64 Adherent: 1.6 mm thick cold rolled mild steel plate Split strength: ASTM D1062-51 Adherent: SS-41 general structural rolled steel material Impact strength: ASTM D950-54 Adherent SS-41 general structural rolled steel material Adherent surface treatment: Triclean degreasing after polishing with No. 240 sandpaper Measurement temperature and humidity: 23℃, 50% RH Adhesion time: 24 hours Γ Measurement of set time After polishing SS-41 steel blocks with a surface area of 3 cm ² (adhesion part) with 240-grit sandpaper and degreasing them with Triclean, stick them together with adhesive until the adhesion starts and it becomes impossible to remove them by hand. The time was measured and set as the set time. In addition, we also measured the time it took to reach practical strength, which is 1/2 of the final strength.
All compositions of the present invention were cured within 1 hour.
In addition, put 50g of adhesive in a 100ml polyethylene container and measure the number of days until the adhesive thickens or gels in a dryer at 50℃.If there is no abnormality for more than 10 days, the adhesive will remain at room temperature for 6 months or more. The present inventors have confirmed that the adhesives are stable for more than one year, and all adhesives were stable for more than 10 days at 50°C. but
When 800 g of the product was filled into a 1000 ml polyethylene container and the stability test described above was conducted, thickening or gelation was observed within 10 days. Therefore, we added 0.05 part of ethylenediamine salt of methacrylic acid as a polymerization inhibitor and conducted a stability test.
It remained stable for more than a day.

[Table] Example 2 In the adhesive composition of Example 1, the amount of water added was
1.0 part, polymerizable phosphoric acid ester shown in the table 2-
Hydroxyethyl methacrylate and phosphorus pentoxide 3
In the same _manner as in Example 1, an adhesive was prepared by adding various salts of polymerizable phosphoric acid ester (hereinafter abbreviated as HEM- _P2O5 ) obtained by reacting at a molar ratio of 1 to 1. Physical properties were measured. The results showed a quick set time of less than 10 minutes and excellent adhesive strength. In addition, as a result of the gelation stability test, all cases of 50g capacity were stable at 50℃ for more than 10 days.
In the case of 800 g capacity, only the ammonium salt and amine salt system was stable for more than 10 days.

[Table] Example 3, Comparative Examples 1 to 11 Under the manufacturing conditions of Example 1, 2-hydroxypropyl methacrylate 50 parts, BPE part 2.6, 50 parts, acrylic polymer 7 parts, STQ salt 1.5 parts, cumene hydroperoxide 0.3 2.0 parts of water, and 0.1 part of polymerizable phosphate ester HEM-P ₂ O ₅ was prepared, and the relationship between adhesion time and tensile shear strength, set time, splitting strength and impact strength at 23°C was determined. Measurement was carried out in the same manner as in Example 1. For comparison, sample Nos. 3C, 4C, 5C of Examples 3 to 5 of JP-A-51-132234 and the special 1977-
Composition numbers 4, 8, and 12 of No. 83572 Example were manufactured according to the Example, and the physical properties were measured by the method of the present inventors. The results are shown in the table and the table below. As is clear from the table and the table, the adhesive strength of Comparative Examples 1 to 5 was very low, and the adhesive strength of Comparative Examples 6 to 11 at 23℃
The adhesive strength is low under the adhesive conditions of . In Comparative Examples 6 to 8, when heat curing was performed at 120°C, some adhesive strength was high, but surface adhesion was low. On the other hand, the adhesive made of the composition of the present invention has a very fast set time and adhesion speed, and curing already begins in 3 to 4 minutes, and almost reaches equilibrium strength in 5 hours. In terms of adhesive strength, it can be seen that the adhesive has good tensile shear, splitting, and impact strengths required for surface bonding, and is well-balanced.

【table】

[Table] Example 4 50 parts of 2-hydroxypropyl methacrylate
Add 7 parts of acrylic polymer to 50 parts of BPE2.6 at 80°C.
The mixture was heated and dissolved for 2 hours. Next, 0.868 parts (0.0047 mol) of o-benzoic sulfimide, 1,2,
3,4-tetrahydroquinoline 0.632 parts (0.0047
mol) or its salt, i.e., STQ salt, was dissolved for 10 minutes and cooled to room temperature, followed by 0.05 part of polymerizable phosphoric acid ester HEM-P ₂ O ₅ , 2.0 parts of water, and 0.3 part of Kun hydroperoxide. The physical properties were measured in the same manner as in Example 1 for an adhesive prepared by stirring and dissolving the mixture, and the results are shown in the table. All of them exhibit good adhesion, but salt-based adhesives tend to have slightly better adhesive strength and less amine odor.

[Table] Example 5, Comparative Examples 12 to 14 50 parts of 2-hydroxypropyl methacrylate
Add 7 parts of acrylic polymer to 50 parts of BPE2.6
The mixture was heated and dissolved at 80°C for 2 hours. Next, 1.5 parts of the S-amine salt shown in the table was added and dissolved by heating for 10 minutes, and after cooling to room temperature, polymerizable phosphate ester HEM
−P ₂ O ₅ 0.05 part, cumene hydroperoxide
The physical properties of an adhesive produced by adding 0.3 parts and 2.0 parts of water and stirring and dissolving were measured in the same manner as in Example 1. As a comparative example, an adhesive was produced in the same manner without adding water and its physical properties were measured. Both S-amine salts exhibit fast set times and high adhesive strengths. It is clear that without water in the adhesive composition, the set time is very slow and the impact strength is also low, indicating that water is essential to the adhesive.

[Table] Example 6 50 parts of BPE2.6, 50 parts of hydroxyl group-containing polymerizable methacrylic ester shown in the table, 7.5 parts of acrylic polymer,
STQ salt 1.5 parts, cumene hydroperoxide 0.5
part, 1.0 part of water and polymerizable phosphate ester HEM−
An adhesive consisting of 0.1 part of P ₂ O ₅ was prepared in the same manner as in Example 1, and the physical properties were measured. The results are shown in the table. Especially 2-
Adhesives from hydroxypropyl methacrylate were excellent.

[Table] Example 7, Comparative Examples 15 to 17 50 parts of 2-hydroxypropyl methacrylate, 50 parts of polymerizable methacrylic acid ester shown in the table, 7 parts of acrylic polymer, 1.5 parts of STQ salt, 0.5 parts of cumene hydroperoxide, 1.0 parts of water and 0.1 part of polymerizable phosphoric acid ester HEM-P ₂ O ₅ was prepared in the same manner as in Example 1, and the physical properties were measured. The results are shown in the table. For comparison, the physical properties of a commercially available epoxy resin and a commercially available anaerobic adhesive were also measured. It can be seen that the adhesive comprising the composition of the present invention is extremely superior to anaerobic adhesives having conventional compositions, and has strength comparable to commercially available epoxy resins for curing at room temperature.

[Table] Example 8, Comparative Examples 18 to 19 50 parts of 2-hydroxypropyl methacrylate,
BPE2.6 50 parts, terminal methacrylate of liquid rubber (adding an equivalent amount of glycidyl methacrylate to the terminal carboxyl group of Ube Industries Hiker CTBNX) 5 parts, STQ salt 1.5 parts, cumene hydroperoxide 0.5 parts, polymerizable phosphorus acid ester
An adhesive consisting of 0.1 part of HEM-P ₂ O ₅ and 0 to 3 parts of water was prepared in the same manner as in Example 1, and the physical properties were measured, and the results were as shown in the table. When water is added, the impact strength in particular increases significantly, and the set time is also significantly faster than in the case without water. When the amount added is 3 parts, there is no problem with the setting time, but there is a tendency that the splitting strength in particular tends to decrease.

[Table] Example 9, Comparative Examples 20 to 21 50 parts of 2-hydroxypropyl methacrylate,
BPE2.6 50 parts, acrylic polymer 7 parts, STQ salt
1.5 parts, cumene hydroperoxide 0.5 parts, water
1.0 part and polymerizable phosphate ester HEM-P ₂ O ₅ 0~
An adhesive consisting of 0.7 parts was prepared in the same manner as in Example 1, and the physical properties were measured. The results are shown in the table. As is clear from the table, the presence of a small amount of HEM-P ₂ O ₅ significantly increases the adhesive strength. However, if it exceeds 0.5 parts, the strength tends to decrease and the setting time tends to become slower.

[Table] Example 10, Comparative Examples 22 to 23 50 parts of 2-hydroxypropyl methacrylate,
BPE2.6 50 parts, acrylic polymer 7 parts, STQ salt
1.5 parts, water 1.0 parts, polymerizable phosphate ester (HEM
An adhesive consisting of 0.1 part of -P ₂ O ₅ and 0 to 2.0 parts of cumene hydroperoxide was prepared in the same manner as in Example 1, and the physical properties were measured and the results are shown in Table XI. As is clear from the table, when cumene hydroperoxide is not added, there is no adhesion at all, but even when only a small amount is added, excellent physical properties are exhibited. On the other hand, when the amount added exceeded 1.0 part, a slight decrease in strength was observed.

[Table] Comparative Example 24 In Example 1, polymerizable phosphate ester
When an adhesion test was conducted using an adhesive composition of HEM-P ₂ O ₅ with the STQ salt removed, no adhesion occurred at all even after 24 hours. Therefore, in the present invention,
It is clear that STQ salt is an essential ingredient. Example 11, Comparative Examples 25 to 27 2-hydroxypropyl methacrylate and
The physical properties were measured in the same manner as in Example 1 for adhesives prepared by changing the mixing composition ratio of BPE2.6 and the amount of acrylic polymer added to keep the viscosity almost constant as shown in Table XII, and the results are shown in the table. . Other additives were 1.5 parts of STQ salt, 0.5 parts of cumene hydroperoxide, 1.0 parts of water, and 0.1 parts of polymerizable phosphoric acid ester HEM-P ₂ O ₅ . As is clear from the table, 90 to 20% by weight of 2-hydroxypropyl methacrylate in the monomer composition is required.

【table】

[Table] Reference Example 1 The table shows the results of measuring the oil surface adhesion of the adhesive in Example 7 in which the polymerizable methacrylic acid ester is urethane polymethacrylate.
The oil used was a cutting oil uniformly applied to the surface of the adherend at a rate of 0.12×10 ^-3 g/cm ² , and the other conditions were as in Example 1.
is the same as As is clear from the table, good values for surface adhesion are maintained even with oil adhesion.

【table】

Claims (1)

[Claims] 1 General formula (1) (However, in the formula, R ₁ is an alkylene group having 2 to 4 carbon atoms, and 1 is an integer of 1 to 8.) 90 to 20% by weight of a hydroxyl group-containing polymerizable methacrylic acid ester and a methacrylic group in the molecule. Adhesive composition a prepared by adding 100 parts by weight of a mixture of 10 to 80% by weight of a polymerizable methacrylic ester having two or more of the following, a to d below, and a polymerization inhibitor as necessary General formula (2) (However, in the formula, R ₂ is hydrogen or a methyl group, R ₃
is an alkylene group having 2 to 4 carbon atoms or a halogenated alkylene group, m is an integer of 1 to 8, and n is 1
or 2. ) 0.005 to 0.5 parts by weight of a polymerizable phosphoric acid ester or a salt thereof. b O-benzoic sulfimide and general formula (3) (However, in the formula, R ₄ and R ₅ represent hydrogen or a methyl group.) Equimolar mixture with amine or indoline represented by the formula, or 0.5 to 5.0 parts by weight of a salt thereof. c 0.005 to 1.0 parts by weight of organic peroxide. d 0.2 to 2.5 parts by weight of water. 2 A polymerizable methacrylic acid ester having two or more methacrylic groups in the molecule has the general formula (4) (However, in the formula, R ₆ and R ₇ are alkylene groups having 2 to 4 carbon atoms, and o and p are 1 or 2, and o+p≦3.) An adhesive composition according to claim 1. 3 Urethane obtained by addition-reacting a polymerizable methacrylic acid ester having two or more methacrylic groups in the molecule with a compound of general formula (1), polyalkylene glycol, and diisocyanate at a molar ratio of 2:1:2. The adhesive composition according to claim 1, which is dimethacrylate. 4 Claims 1 to 4, characterized in that the salt of the polymerizable phosphoric acid ester represented by the general formula (2) is a metal salt, an ammonium salt, or an amine salt consisting of an alkali metal or alkaline earth metal. The adhesive composition according to any one of item 3. 5. The adhesive composition according to any one of claims 1 to 4, wherein the polymerization inhibitor is an ammonium salt or an amine salt of an organic acid. 6. The adhesive composition according to any one of claims 1 to 5, wherein the organic peroxide is a hydroperoxide.