JPS62265314A - Anaerobically curable composition - Google Patents

Abstract

PURPOSE:To obtain the title composition which can give an adhesive excellent in adhesive strength upon curing, by mixing a specified polymerizable monomer with an organic peroxide and an organic amine. CONSTITUTION:A mixture (A) comprising a polymerizable monomer (a) of the formula (wherein R1-2 are each H or CH3 and R3 is H or a lower alkyl), e.g., 3-hydroxy-3-methylbutyl methacrylate, and optionally a radical-polymerizable compound (b) is mixed with 0.1-10wt%, based on component A, organic peroxide (B) (e.g., cumene hydroperoxide) as a polymerization catalyst, 0.01-5wt%, based on component A, organic amine (C) (e.g., benzoic sulfimide) as a polymerization catalyst and, optionally, 0.005-0.5wt%, based on component A, stabilizer (D) (e.g., 1,4-benzoquinone) and, if necessary, a water-soluble polymer, an inorganic filler and a colorant are added to the obtained mixture.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an anaerobic curable composition, and particularly to an anaerobic curable composition that provides high adhesive strength when cured as an adhesive.

(Prior art) Anaerobic curable compositions, due to their unique polymerization initiation mechanism,
Particularly effective for bonding between two adjacent surfaces, such as bonding metal, wood, glass, etc., preventing loosening of bolts and screws, fixing fitting parts of gears, shafts, etc., and preventing leakage of gases and liquids. It is widely used.

Conventionally, diesters and polyesters of polyhydric alcohols and unsaturated carboxylic acids have been widely used as polymerizable additives that are the main ingredients of known anaerobic curable compositions.

(Problems to be Solved by the Invention) However, since these polymerizable polymers have bifunctionality or higher polyfunctionality, gelation occurs before the curing reaction progresses sufficiently, and the curing reaction is delayed. Things didn't go smoothly;
There are disadvantages such as it takes a long time to completely cure, and the impact strength of the cured product is poor due to the formation of cross-linked bonds and cross-linked bonds.

Furthermore, Japanese Patent Publication No. 45-33665 proposes a composition containing mono(meth)acrylates such as ethylene glycol and 1,2-propylene glycol as an anaerobic curable composition that has improved these drawbacks. There are, but
The drawback is that the adhesive strength when cured as an adhesive is not sufficient.

An object of the present invention is to eliminate the drawbacks of the prior art described above, to provide an anaerobic curable composition in which the curing reaction proceeds smoothly and the cured product has excellent adhesive strength.

(Means for Solving the Problems) As a result of studies to improve the above-mentioned drawbacks, the present inventors found that polymerizable monomers having the general formula (wherein R1 and R2 are the same or different) L) represents H or a CH3 group, and R3 represents H or a lower alkyl group. ) It was discovered that an anaerobic curable composition with good adhesive performance without the above-mentioned drawbacks can be obtained when one or a mixture of the polymerizable compounds shown in (1) is used, and the present invention has been achieved.

Anaerobic curability as defined in the present invention refers to the property that it remains liquid while in contact with air or oxygen, but when air or oxygen is cut off, it can cause a polymerization reaction and rapidly harden.

Examples of the polymerizable compound of the present invention include 3-hydroxy-3
-Methylbutyl (meth)acrylate, 3-hydroxy-3-ethylbutyl (meth)acrylate, 3-methoxy-3-methylbutyl (meth)acrylate, 3-methoxy-3-ethylbutyl (meth)acrylate, 2-hydroxy-2-methyl There are pentane (meth)acrylates, and among these, 3-hydroxy-3-methylbutyl (meth)acrylate and 3-methoxy-3-methylbutyl (meth)acrylate are preferably used.

In the composition according to the present invention, in addition to the polymerizable heptamer represented by the above general formula, a compound having radical polymerizability can also be present. Such compounds include (meth)
Acrylic acid, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, cyclohexyl (meth)acrylate, other alkyl or cycloalkyl (meth)acrylate acrylate, tetrahydrofurfuryl (meth)acrylate, glycidyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, 2-hydroxyethyl (
meth)acrylate, 2-hydroxypropyl(meth)
Examples include (meth)acrylic acid and its esters such as acrylate, styrene, vinyl acetate, and acrylonitrile.

Note that the term (meth)acrylate as used herein is a general term for acrylic esters and methacrylic esters.

Although these are monofunctional compounds, polyfunctional compounds having radical polymerizability can be mixed in the composition of the present invention. These compounds include polyhydric alcohol poly(meth)acrylate, polyester poly(
meth)acrylate, epoxy(meth)acrylate,
Examples include polyurethane (meth)acrylate.

As the polymerization catalyst used in the present invention, known organic peroxides are used, and the types thereof are not particularly limited, but among them, those with relatively high critical temperatures, such as tertiary-butyl hydroperoxide and cumene. Hydroperoxides, such as hydroperoxide, di-isopropylbenzene hydroperoxide, para-menthane hydroperoxide, are particularly recommended to maintain good stability of the compositions of the invention.

The amount used varies slightly depending on the type of catalyst selected, the amount of active oxygen, etc., but it is 0.
．． A range of 1 to 10% by weight, preferably 0.5 to 5% by weight is suitable. If it exceeds 10% by weight, storage stability will be impaired, and if it is less than 0.1% by weight, curing will not be performed sufficiently and adhesive performance will deteriorate.

As an additive for promoting the polymerization reaction, it is desirable to add an organic amine or imide as a polymerization promoter to the anaerobic curable composition together with the above-mentioned organic peroxide.

Organic amines or imides to be added include triethylamine, tributylamine, dimethylaniline, N, N
- tertiary amines such as dimethyl-p-toluidine, 1.
Heterocyclic 2 such as 2,3゜4-tetrahydroquinoline
amines, organic sulfimides such as 0-benz sulfimide, benzo t-m sulfimide, and the like. The amount of these additives added is 0.01 per polymerizable 7-mer.
A range of 5 M% is suitable. If the amount added exceeds 5% by weight, storage stability will be impaired, and if it does not reach 0.01% by weight, the effect on polymerization promotion will be reduced.

In order to maintain the storage stability of the anaerobic curable composition containing the organic peroxide, organic amine or imide, stabilizers such as 1,4-benzoquinone, 2,5
It is preferred to add quinones such as -hydroxy-p-benzoquinone. The amount added is determined depending on the constituent components of the anaerobic curable composition and the purpose of use, but it is preferably in the range of 5 to 0.51Q% of O,OO based on the polymerizable monomer.

The composition of the present invention may contain, for example, polymethyl methacrylate, polyethyl acrylate, polybutadiene, styrene-butadiene copolymer, acrylonitrile-
Adding soluble polymers such as butadiene copolymer, inorganic fillers such as fine high silicic acid, calcium silicate, calcium carbonate, and titanium dioxide, and coloring agents such as dyes and pigments,
It can also increase its practical value.

When actually using the composition of the present invention, a composition with an appropriate viscosity depending on the type and shape of the material is used so that air is completely blocked between two adjacent surfaces, and the composition is adhered without leaving any voids. It is important to operate the adhesive so that it can be applied uniformly over the entire surface to fully exhibit its adhesive effect. The anaerobic curing speed of the composition of the present invention is fast and easy to use when the materials to be adhered are metals or at least one of them is metal. In addition, in the case of materials other than metals, curing takes a relatively long time, but after pre-treating the surface of the adherend with a polymerization accelerator, for example, pre-treating the adherend with a low boiling point solution of a polymerization accelerator substance. If adhesive is used, curing will be faster.

When the composition of the present invention is used as an adhesive while blocking air or oxygen, the polymerization reaction is initiated by the action of the polymerization catalyst, resulting in rapid curing and excellent adhesive strength.

Examples of the present invention will be described below. In addition, the measurement of the breaking torque and the measurement of the tensile shear strength in the examples were performed as follows.

Measurement of fracture torque: Apply an anaerobic hardening composition to the head of a steel bolt (JIS B1180 MIO1 nominal length 45 mm) that has been previously degreased with trichlorethylene, and apply it to a steel nut that has been previously degreased with trichlorethylene in the same way as the bolt ( J
A bolt/nand was assembled using an IS B1181M10.1 type) with an initial tightening torque of 0, and after being left at room temperature for 24 hours, the breaking torque was measured using a torque wrench (manufactured by Higashiguchi Seisakusho, model 460F).

Measurement of tensile shear strength: According to JIS-6850, tensile shear adhesive strength testing method for adhesives. As the test piece material, JISG3141
(Cold-rolled steel plates and steel strips) Class 1, thickness 1.
Using a 6 am steel plate, the strength was measured 24 hours after adhesion using a strength testing machine (Shimabara Autograph (DS).
S-5000) was used. Note that adhesion, standing, and strength measurements were all carried out at a temperature of 23°C±1°C.

(Example) Example 1 50 g of 3-hydroxy-3-methylbutyl methacrylate as a polymerizable monomer, 2 g of cumene hydroperoxide as a polymerization catalyst, 0.25 g of benzoic acid sulfimide and 0.0 g of dimethyl p-toluidine as a polymerization accelerator. When the breaking torque of the composition in which 25 g of 1,4-benzoquinone O, OO as a stabilizer was dissolved was measured, it showed a value of 460 kg-cm or more.

Example 2 The breaking torque of a composition prepared by dissolving 10 g of 3-hydroxy-3-methylbutyl acrylate as a polymerizable additive, 0.4 g of cumene hydroperoxide as a polymerization catalyst, and 0.2 g of triethylamine as a polymerization accelerator. When measured, it showed a value of 400 kg-Cm.

Example 3 As a polymerizable additive, 10 g of 2-hydroxy-2-methylpentane methacrylate, 0.2 g of cumene hydroperoxide as a polymerization catalyst, 0.1 g of benzoic acid sulfimide as a polymerization accelerator, and 0.05 g of dimethyl p-toluidine. When the breaking torque of the composition prepared by dissolving 400 kg was measured, it showed a value of 400 kg.

Example 4 8 g of 3-hydroxy-3-methylbutyl methacrylate, polyurethane acrylate (
Osaka Organic Chemical Industry Type Product Name Viscoat #855) 2g
and 0.2 g of cumene hydroperoxide as a polymerization catalyst.

0.08 g of benzoic acid sulfimide as a polymerization accelerator;
When the breaking torque and tensile shear strength of the composition in which 0.05 g of dimethyl para-toluidine and 2 g of 1,4-benzoquinone O,OO as a stabilizer were dissolved were measured, they were 440 kg-cm and 150 kg, respectively.
/adO value was shown.

Example 5 A polymerization catalyst was added to a mixture consisting of 7.8 g of 3-hydroxy-3-methylbutyl methacrylate, 0.2 g of acrylic acid, and 2 g of polyurethane acrylate (Osaka Organic Chemical Industries, trade name: Visco-#855) as polymerizable monomers. 0.2 g of cumene hydroperoxide, 0.08 g of benzoic acid sulfimide O as a polymerization accelerator, 0.05 g of dimethyl para-toluidine, and as a stabilizer,
The breaking torque and tensile shear strength of a composition in which 0.002 g of 1.4-benzoquinone was dissolved were measured.
The values were 430 kg-cm and 210 kg/crA, respectively.

Example 6.

As a polymerizable additive, 10 g of 3-hydroxy-3-methylbutyl methacrylate, 0.2 g of cumene hydroperoxide as a polymerization catalyst, 0.08 g of benzoic acid sulfimide as a polymerization accelerator, and 0.05 g of dimethyl p-toluidine, and When the breaking torque and tensile shear strength of a composition prepared by melting 0.002 g of 1,4-benzoquinone as a stabilizer were measured, the result was 4.
It showed values of 60 kg-cm or more and 70 kg/cIN.

(Effects of the Invention) According to the present invention, by using a specific polymerizable adhesive, it is possible to obtain an anaerobic curable composition that exhibits extremely high adhesive strength upon curing.

Claims (2)

[Claims] (1) General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (In the formula, R_1 and R_2 may be the same or different H
or CH_3 group, and R_3 means H or a lower alkyl group. ), an organic peroxide as a polymerization catalyst, and an organic amine as a polymerization promoter. (2) Claim (1) is characterized in that it contains a polymerization catalyst in an amount of 0.1 to 10% by weight based on the polymerizable monomer, and a polymerization accelerator in an amount of 0.01 to 5% by weight based on the polymerizable monomer. An anaerobic curable composition.