JPS6015661B2 - Adhesives and their manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an adhesive made of boric acid ester having a polymerizable double bond in its molecule, and its purpose is to be able to be used in the field of anaerobic adhesives, and to The purpose of this invention is to overcome the drawback of anaerobic adhesives, which is that they are not air-curable, and to provide an air-curable adhesive.

Anaerobic adhesives are well known as curable compositions using acrylic monomers.

This adhesive takes advantage of the fact that acrylic monomers are inhibited from polymerization by oxygen in the air, and is made of acrylic monomers, organic peroxides, and other additives. It is a one-component adhesive that can be stored at room temperature for long periods of time without gelling by filling the adhesive with water and maintaining contact with air. If this is applied or penetrated into minute gaps between metals, contact with air is eliminated and polymerization starts, allowing them to be bonded together. This anaerobic adhesive is overnight and has a low viscosity, and can be bonded at room temperature, making it a highly workable adhesive. It has the disadvantage that it does not harden, and that if the gaps between the adherends are large and they are likely to come into contact with air, the curability becomes extremely poor. The protruding parts do not harden forever, so tedious work such as wiping them off is required after adhesion.Furthermore, if wiping off is not possible, the aesthetics of the bonded product may be impaired, it may emit a bad odor, it may stick to the human body, and other environmental health problems. Not good. Apart from this anaerobic adhesive, there are two-component acrylic structural adhesives.

The main component is alkyl methacrylate, which is relatively weakly anaerobic, that is, it is not susceptible to the polymerization inhibition effect of oxygen during curing, and the A component is a mixture of a special rubber component dissolved in this and a curing agent added. This is a two-component adhesive consisting of component B and component A, which is prepared by adding a curing accelerator to a system in which the curing agent is removed from component A. Unlike anaerobic adhesives, it does not need to be a one-component product, so a weakly anaerobic monomer can be used, but even so, the surface that overflows from the adherend will not completely cure and remain sticky. , paraffin wax is added to harden the surface in contact with air (hereinafter abbreviated as surface hardening). Unlike epoxy resins, this type does not require the precise measurement and mixing of two components, and it has recently attracted attention because it cures at room temperature in a short time and has a strong adhesive effect.
However, the adhesive strength of paraffin wax tends to decrease as the amount of paraffin wax added increases. If a large amount of a strong monomer is used, it is no longer possible to harden the surface even by adding paraffin wax. Other surface-curing methods for acrylic curable compositions include blocking the surface with an inert gas during curing, forcibly curing with ultraviolet rays or heat energy, and methods described in Tokokukan Sho 51-1142492. Examples include pre-treatment with a special curing accelerator, or mixing two liquids immediately before use. However, these methods are also complicated and unsatisfactory. In order to eliminate the drawbacks of these known technologies, the present invention has been made through intensive research and has resulted in the discovery of a compound that itself has an adhesive effect as well as imparting novel air-curing properties based on a new action, resulting in the present invention. It is.

That is, it was discovered that boric acid esters having polymerizable double bonds harden to the surface in air and eliminate tackiness, and furthermore, a certain amount of these esters was added from the anaerobic adhesive to the two-component acrylic adhesive. At the time, they discovered that sufficient surface hardening could be obtained even without the addition of paraffin wax or the like, and even with highly anaerobic monomers. In particular, it is surprising that although it is a one-component anaerobic adhesive, it has succeeded in having the seemingly contradictory effect of curing the surface in contact with air at room temperature. The reason why surface hardening is restricted by the addition of polymerizable boric acid esters is not clear, but the boric acid esters present on the surface in contact with air form a thin film due to the influence of moisture in the air, and this causes internal hardening. The acrylic monomer is cut off from oxygen and cured, and the boric acid ester itself is also cured, so that the surface can be cured.

Therefore, when storing a curable composition containing a polymerizable boric acid ester, it is sufficient to simply store it in a moisture-tight container such as polyethylene with a well-sealed container, and it will prevent gelation and surface hardening for a long period of time. It does not cause The boric acid ester having a polymerizable double bond used in the present invention is a monomer having one or two or more polymerizable double bonds and alcoholic hydroxyl groups or epoxy groups in the molecule, respectively. It is preferable to use a product obtained by reacting at an equivalent ratio of .

QBQ: Alcoholic hydroxyl group = 1:1-3&03: Alcoholic hydroxyl group = 1:4-6 Melon BQ: Epoxy group = 1:
2-3 Although the structure of the product and the reaction are not clear, it is thought that the reaction proceeds roughly as follows.

However, R represents an organic group having a polymeric double bond. Melon BQ+nROH→ (RO)nB(OH)3-n+n ratio 0 (n is 1 to 3) &
03 Toka OH → 2 (RO) 2B (OH) Toka 20 & 03
Juji OH → 2 (RO) 3B 13th 20 (Misaki Ma 2 or 3
) The reaction temperature is from 60 to 100 pm, and if water is generated in the presence or absence of an inert solvent, the desired polymerizable double bond-containing borosilicate can be easily obtained by performing the reaction while removing water from the system. You can get acid ester.

Examples of compounds having a polymerizable double bond and an alcoholic hydroxyl group in the molecule include ethylene glycol monomethacrylate, propylene glycol monomethacrylate, butylene glycol monomethacrylate, polyethylene glycolyl monomethacrylate, polypropylene glycolyl monomethacrylate, glycerin monomethacrylate, Examples include methacrylates such as glycerin dimethacrylate and acrylates thereof. Examples of compounds having a polymerizable double bond and an epoxy group in the molecule include glycidyl methacrylate and glycidyl acrylate. The polymerizable phosphoric acid ester obtained in this way is generally a low viscosity transparent liquid, and even when used alone, it can be used as an organic peroxide,
A curable composition with surface curability can be obtained by combining a polymerization inhibitor and a curing accelerator, but by adding an appropriate amount to a conventional acrylic curable composition, surface curable compositions can be obtained. You can also have it.

In general, it is preferable to add a large amount when the composition is strongly anaerobic and has a slow curing rate, whereas a small amount is effective when the composition is weakly anaerobic and has a fast curing rate.

The larger the amount added, the better the surface hardening properties will be, but it is usually preferably at least 2% by weight of the monomer composition. As described above, the present invention imparts specific air curability to acrylic curable compositions that leave surface tackiness after curing, and is capable of imparting unique air curability to highly anaerobic compositions, which was previously impossible. It can also be easily cured at room temperature down to the air-contact surface, making it a great contribution to the development of this industry.

Hereinafter, the present invention will be explained in detail by manufacturing examples, examples, and comparative examples. However, all parts indicate parts by weight. Production example 1 Put 2/3 mol of 2-hydroxyethyl methacrylate (95.24 g) into a four-necked flask equipped with a thermometer, a fly trap, and a water collection trap, and heat the melon B031 at 80°C while holding a candle.
20.61 /3 mol was added.

After the addition was completed, the pressure was maintained at reduced pressure using an aspirator, and the reaction was carried out while removing generated water from the system. The system becomes completely transparent,
The end point was the point at which no more water was distilled out. The obtained boric acid ester having a polymerizable double bond had a viscosity of 30. &p/
It was a colorless and transparent liquid at 23°C. Yield: 99 yen. Manufacturing example
2. 4 equipped with a thermometer, fly-azusa device, and benzene-water separator.
Put 0.6 moles of 2-hydroxypropyl methacrylate (89.34 moles), 102 moles of benzene, and 0.02 moles of hydroquinone (200 moles) as a polymerization inhibitor into a two-glass flask, and while holding a light, pour the melon. 12.37 mols of 2 mol were added.

After the addition was completed, the reaction was carried out while separating the produced water under benzene reflux, and the end point was defined as the point in time when no water was produced. Then, benzene was distilled off under reduced pressure to obtain a colorless and transparent boric acid ester having a polymerizable double bond and having a viscosity of 30.7 cp. Produced water was 10.0 [(theoretical value 10.8'), yield 91.7 hours. Production Example 3 Under the same conditions as Production Example 2, 0.3 mol of 2-hydroxypropyl methacrylate 44.7
0 and 38,030.15 moles of 9.27 moles were reacted.

The product is colorless and transparent with a viscosity of 90. The pillow was p/2chi0.
Produced water 5.6 [(theoretical value 5.4 [)], yield 48.4
evening. Production Example 4 Under the same conditions as Production Example 1, 2-hydroxyethyl methacrylate 0.5 mol 71.43 Sun and Sun 3B0 30.5 mol 3
0. It made Kanyu react.

The obtained boric acid ester having a polymerizable double bond is colorless and transparent and has a viscosity of 939. &p/2yo.

Yield: 89.25 pm. Production example 5 2 under the same conditions as production example 1
-Hydroxyethyl methacrylate 0.6 mol 8572
0.2 moles of B03 and 12.37 moles were reacted.

The obtained boric acid ester having a polymerizable double bond was free.
The color was transparent and the viscosity was 19.1 cp/2 mm. Yield 86
．． 82 evening. Production Example 6 Under the same conditions as in Production Example 1, 0.6 moles of 2-hydroxypropyl methacrylate (89.34 moles) and 0.1 moles of B203 (096 moles) were reacted.

The obtained boric acid ester having a polymerizable double bond is colorless and transparent and has a viscosity of 24. It was $p/23°C. Yiyoshi Satoshi. 83
evening. Production Example 7 Under the same conditions as Production Example 1, 0.6 mol of 2-hydroxyepropyl methacrylate was added at 89.34 hours and 03 hours. 15 moles and 12.28 moles were reacted.

The obtained boric acid ester with polymerizable double bonds is colorless and transparent and has a viscosity. My father was p/2 protector 0.

Yield team. Meiyu. Production Example 8 0.6 mol of glycidyl methacrylate 87.83 evening and day 3 B03 0.3 mol 18.
The mixture was heated for 55 minutes and allowed to react at 90°C while shaking the rope. As the reaction progressed, the crystals of Day 3803 disappeared and it became a completely colorless and transparent liquid in 7 hours. The obtained boric acid ester having a polymerizable double bond has a viscosity of 954.9p/23℃ yield 1
It was 06.40 evening. Production Example 9 Glycidyl methacrylate 0.6 under the same conditions as Production Example 8
87.83 moles of Melon B03 and 12.37 moles of Melon B030 were reacted.

The obtained boric acid ester having a polymerizable double bond had a viscosity of 91. It was a colorless transparent liquid with a temperature of $p/23°C. Yield 10
0.20 evening. Examples 1 to 4, Comparative Example 1 Dimethacrylate of 2.6 mol adduct of bisphenol A ethylene oxide (manufactured by Shin-Nakamura Ib Gaku Kogyo Co., Ltd., N
A mixture of Kester BPE2.6), 2-hydroxypropyl methacrylate, and the boric acid ester obtained in Production Example 1 (mixing ratios are shown in Table 1) 10 parts 1.0 part of 1.0 part of 1.2.3.4.tetrahydroquinoline and 0.5 part of 1.2.3.4.tetrahydroquinoline were added and dissolved in 80 minutes.

Then, after cooling to room temperature, cumene hydroperoxide 2
．． 0 parts was added and mixed well to prepare a one-component anaerobic adhesive. Table 1 shows the results of measuring the surface curing time and adhesive strength of the air contact surface of the obtained adhesive. The adhesive was stored at room temperature in a 50M low-density polyethylene container with a 100M container, which was tightly capped, and was stable for more than 3 months without any changes such as gelation or thickening. The surface hardening time is determined by applying adhesive to the MIO de-walled steel bolt in a room at 23°C and 50% RH, screwing in the nut, letting it stand, and touching the adhesive overflowing from the nut with your hand. The time until it disappeared was measured.

The adhesive strength was determined by gluing MI Tanaetsu steel bolts and nuts in the same way and measuring the return torque with a torque wrench after 2 feeding hours.
The value when the adhesive first broke due to rotation was taken as the failure torque, and the average value of the torques after 1/4, 1/2, 3/4, and 1 rotation was taken as the escape torque. As is clear from Table 1, the composition of Comparative Example 1, which does not contain boric acid ester, remains liquid even after being left for more than one month, but the composition of the present invention containing boric acid ester, Example 1 to 4 is 1~
The surface was completely cured in 5 days. Table 1 Examples 5 to 8, Comparative Example 2 Methyl methacrylate 42.5 parts, nitrile rubber 15.
2-hydroxyethyl methacrylate and the boric acid ester obtained in Production Example 1 were mixed in Miyako (Nipole 1042 manufactured by Nippon Zeon ■) in the prescribed amounts shown in Table D, 0.05 part of hydroquinone was added, and the mixture was heated at 80 qo. It was heated for .5 hours to dissolve.

This was divided into two halves, each having 5 parts, and 1.5 parts of cumene hydroperoxide was added to one part to prepare liquid A. remaining 5
Add 0.5 part of ethylene thiourea and 0.05 part of vanadial acetylacetonate to the base part 1 and mix at 80 oo
The mixture was heated and dissolved for a minute to obtain liquid B. The surface curing time and adhesive strength of the two-component adhesive thus obtained were measured. The surface hardening time was determined by dropping two drops of liquid A and liquid B on a well-polished steel plate, mixing them thoroughly, and then leaving them in a room at 230050% RH to measure the time until the surface tackiness disappeared. For adhesive strength, tensile strength, splitting strength, and impact strength are determined according to ASTM DIO02-64 DI062-51, respectively.
Measured according to D950-54.

However, the adherend used was a steel plate of SS41 polished with 24mm sandpaper and then polished with Triclean.
After applying liquid A and liquid B to separate planes of the adherend in step 3, they were glued and fixed together by rubbing lightly, and the strength was measured after two hours. The results are shown in Table 0'.
As is clear from the table, as the amount of boric acid ester added increases, the surface curing time becomes shorter. The system of Comparative Example 2, which did not contain boric acid ester, remained tacky on the surface for a long period of time and rusted in the area overflowing from the adherend. The occurrence of rust is thought to be caused by the adhesive absorbing moisture in the air, but the composition of the present invention forms a thin film on the air contact surface immediately after bonding to prevent moisture from entering and harden, so rust does not occur at all. I was not able to admit. Table □Examples 9-17,
Comparative Example 3 25 parts of terminally methacrylated liquid polybutadiene (NissoPBTE-2000 manufactured by Nippon Soda ■, tolylene diocyanate and 2-hydroxyethyl methacrylate added to both ends of hydroxyl group-terminated liquid polybutadiene), 25 parts of methyl methacrylate, 2 - One part of hydroxyethyl methacrylate and four parts of the boric acid ester having a polymerizable double bond obtained in Production Examples 1 to 9 were mixed, and the mixture was heated at 80°C for 20 minutes to dissolve.

This was cooled and divided into two equal parts of 5 parts, 1.5 parts of cumene hydroperoxide was added to one part to form component A, and to the other part 0.5 part of ethylene thiourea and 0.1 part of vanadyl acetylacetonate. was added and melted by heating at 8,000° C. for 1 minute to obtain component B. Table m shows the results of measuring the physical properties of the two-component adhesive thus obtained in the same manner as in Examples 5 to 8. All of the compositions of the present invention containing boric acid esters were hardened to the surface in 1 to 5 days, and no rust was observed.

On the other hand, the system of Comparative Example 3, which did not contain boric acid ester, remained sticky on the surface even after being left for a long period of time, and the areas overflowing from the adherend were rusted. Table m *A system containing 50 parts of 2-hydroxyethyl methacrylate in total without containing boric acid ester.

Claims (1)

[Scope of Claims] 1. An adhesive characterized by being made of a boric acid ester having a polymerizable double bond in the molecule obtained by reacting the following (a) or (b) with inorganic boric acid. agent. (a) Acrylate or methacrylate which is an ester of polyhydric alcohol and acrylic acid or methacrylic acid and has at least one alcoholic hydroxyl group in the molecule. (b) Glycidyl acrylate or glycidyl methacrylate. 2. A dehydration esterification reaction of acrylate or methacrylate, which is an ester of polyhydric alcohol and acrylic acid or methacrylic acid and has at least one alcoholic hydroxyl group in the molecule, and H_3BO_3 or B_2O_3 at the following equivalent ratio, A method for producing an adhesive made of a boric acid ester having a polymerizable double bond in the molecule thus obtained. H_3BO_3: alcoholic hydroxyl group = 1:1-3B_
2O_3: Alcoholic hydroxyl group = 1:4-63 Glycidyl acrylate or glycidyl methacrylate and H_3BO_3 are subjected to an addition esterification reaction at the following equivalent ratio, and a boric acid ester having a polymerizable double bond in the molecule thus obtained is used as a material. A method for manufacturing adhesives. H_3BO_3: epoxy group = 1:2-3