JPH024604B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention allows easy adjustment of the viscosity to an appropriately low level for good workability during use. The present invention relates to an anaerobic adhesive composition with excellent properties and flexibility. (Prior Art) Anaerobic adhesive compositions normally remain liquid and do not harden when in contact with air or oxygen, but they have the property of rapidly polymerizing and hardening when cut off from air or oxygen. Therefore, various sealants have been widely put into practical use, for example, for fixing threaded parts of bolts and nuts, and for fixing bearing shafts. However, with the development of the electronics industry in recent years, more advanced requirements such as improved fast curing, improved heat resistance, and adaptability to more types of base materials are required, and even higher quality In order to meet the demand for improved productivity, there are high expectations for UV-curable anaerobic adhesives that have not only anaerobic curability but also UV curability. Several efforts have been made in the past to meet these requirements. For example, a method for rapid curing by combining a hydrophilic anaerobically polymerizable monomer that can contain a small amount of water, a limited catalyst system, and water (Japanese Patent Application Laid-open No. 59-207977), A method of improving heat resistance by using di(meth)acrylate contained in the product (Japanese Patent Application Laid-Open No. 150491/1989), and a method of improving thermal properties by combining di(meth)acrylate oligomer with phenylmaleimide or bismaleimide. (Japanese Patent Publication No. 59-13555), there is a method in which acrylates such as hydroxyethyl acrylate and ethyl acrylate are added as a diluent to lower the viscosity of the composition and improve workability during use. However, these methods can be used in cases where the water resistance and heat resistance are insufficient even though the composition is fast curing, or when the fast curing property is not sufficient although the heat resistance is improved, or the viscosity of the composition is too high. At present, problems still remain in both cases, such as when the viscosity is low and the workability is good, but the heat resistance is insufficient. (Problems to be Solved by the Invention) In order to solve the above-mentioned problems, the present inventors have conducted intensive research and found that a (meth)acrylic oligomer and a free radical polymerization initiator are combined with a diester of fumaric acid and a maleimide compound. When used as a adhesive, it was found that the viscosity could be easily adjusted to a moderately low level for good workability, that it cured quickly, and that the cured product had excellent heat resistance and flexibility. They discovered this and completed the present invention. (Means and effects for solving the problem) That is, the present invention provides one or more (meta) molecules in one molecule.
(Meth)acrylic oligomer with acryloyl group (A), fumaric acid diester (B), general formula (However, in the formula, R ₁ and R ₂ are each independently hydrogen, halogen, an alkyl group having 1 to 15 carbon atoms, an aryl group, or a substituted aryl group, and R ₃ is hydrogen,
Alkyl group having 1 to 15 carbon atoms, cycloalkyl group,
It is an aryl group or a substituted aryl group. ) The present invention relates to an anaerobic adhesive composition comprising a maleimide compound (C) represented by the following formula and a free radical polymerization initiator (A). The (meth)acrylic oligomer (A) used in the present invention has one (meth)acryloyl group in one molecule.
Although any combination containing 2 or more (meth)acryloyl groups is included, it is common to use a combination in which a di(meth)acrylate oligomer containing two (meth)acryloyl groups in one molecule is the main one. The optimal combination of these (meth)acrylic oligomers may be selected depending on the purpose of use. Examples of (meth)acrylic oligomers (A) include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, and tetraethylene glycol di(meth)acrylate. (meth)acrylate, dipropylene glycol di(meth)acrylate, dipentamethylene glycol di(meth)acrylate, tetraethylene diglycerol tetra(meth)acrylate, tetramethylene di(meth)acrylate, neopentyl glycol di(meth)acrylate
Acrylate, 1,3-butanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, bis Di(meth) of phenol A alkylene oxide adduct
Acrylate, di(meth)acrylate of halogenated bisphenol A alkylene oxide adduct, di(meth)acrylate of bisphenol S alkylene oxide adduct, poly(meth)acrylate of polyhydric alcohol such as glycerine di(meth)acrylate , polyester poly(meth)acrylates, urethane poly(meth)acrylates, epoxy poly(meth)acrylates, methyl(meth)acrylate, hydroxyethyl(meth)acrylate, hydroxypropyl(meth)acrylate, glycidyl(meth)acrylate Acrylate, cyclohexyl (meth)acrylate, phenoxyethyl (meth)acrylate, lauryl (meth)acrylate, diphenyl (meth)acryloyloxyethyl phosphate,
Dibutyl (meth)acryloyloxyethyl phosphate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, isobornyl (meth)acrylate, tris(meth)acryloyloxyethyl phosphate, tris(meth) Examples include acryloyloxyethyl isocyanurate, tri(meth)acryloylhexahydro-s-triazine, and the like. The fumaric acid diester (B) used in the present invention is a diester of fumaric acid and an alcohol having an alkyl group, a cycloalkyl group, an aryl group, or a substituted aryl group having 1 to 20 carbon atoms. They may be the same or different. These diesters of fumarate include, for example, dimethyl fumarate, diethyl fumarate, dipropyl fumarate, diisopropyl fumarate, dibutyl fumarate, diisobutyl fumarate, disec.butyl fumarate, dit-butyl fumarate, diamyl fumarate, fumarate. diisoamyl acid, dihexyl fumarate, diheptyl fumarate, dioctyl fumarate,
Di-2-ethylhexyl fumarate, dinonyl fumarate, didecyl fumarate, dilauryl fumarate,
Examples include dicyclohexyl fumarate and dibenzyl fumarate. Depending on the type of (meth)acrylic oligomer used in the anaerobic adhesive composition, the viscosity may be high, which often causes problems in workability, but the fumaric acid diester (B) used in the present invention is a (meth)acrylic oligomer. It has a plasticizing effect on oligomers (A) and maleimide compounds (C), making it easy to adjust the composition to an appropriate viscosity, and reducing the tendency for heat resistance to decrease in conventional viscosity-lowering agents. It is not visible at all, but rather has the effect of improving heat resistance and imparting flexibility. The maleimide compound (C) used in the present invention is represented by the above general formula, and R ₃ is preferably an aryl group or a substituted aryl group. The maleimide compound (C) greatly contributes to improving the heat resistance of the resulting composition, and it also provides fast curing properties, especially in curing systems that use ultraviolet irradiation, which improves productivity. It is something that connects. Most maleimide compounds (C) are solid at room temperature, so (meth)acrylic oligomers
Although the solubility in (A) may be limited or the viscosity of the composition may increase, as described above, fumaric acid diester (B) has a favorable effect on such problems. When using the maleimide compound (C), one type or two or more types can be effectively used depending on the purpose of use. Examples of these maleimide compounds (C) include maleimide, N-methylmaleimide,
N-ethylmaleimide, N-propylmaleimide, N-isopropylmaleimide, N-butylmaleimide, N-isobutylmaleimide, N-tertiarybutylmaleimide, N-cyclohexylmaleimide, N-laurylmaleimide, N-phenylmaleimide, N- (2-chlorophenyl)maleimide, N-(3-chlorophenyl)maleimide,
N-(4-chlorophenyl)maleimide, N-(4
-bromophenyl)maleimide, N-(2,4,
6-trichlorophenyl)maleimide, N-(2,
4,6-tribromophenyl)maleimide, N-
(2-methylphenyl)maleimide, N-(3-methylphenyl)maleimide, N-(4-methylphenyl)maleimide, N-(2-tertiarybutylphenyl)maleimide, N-(3-tertiarybutylphenyl)maleimide , N-(4-tertiarybutylphenyl)maleimide, N-(2,6
-dimethylphenyl)maleimide, N-(2-nitrophenyl)maleimide, N-(3-nitrophenyl)maleimide, N-(4-nitrophenyl)
Maleimide, N-(2,4-dinitrophenyl)
maleimide, N-(2-hydroxyphenyl)maleimide, N-(3-hydroxyphenyl)maleimide, N-(4-hydroxyphenyl)maleimide, N-(2-methoxyphenyl)maleimide,
N-(3-methoxyphenyl)maleimide, N-
(4-methoxyphenyl)maleimide, N-(4-
ethoxyphenyl)maleimide, N-(2-methoxy-4-chlorophenyl)maleimide, N-
(4-Phenylphenyl)maleimide, N-(4-
phenyloxyphenyl)maleimide, N-(4-
benzylphenyl)maleimide, N-(4-benzyloxyphenyl)maleimide, N-(4-phenoxymethylphenyl)maleimide, N-(2-
chloro-4-phenoxyphenyl)maleimide,
Examples include N-naphthylmaleimide, N-(2-carboxyphenyl)maleimide, N-(4-carboxyphenyl)maleimide, and the like. As the free radical polymerization initiator (D), known free radical polymerization initiators such as hydroperoxides, ketone peroxides, dialkyl peroxides, peroxy esters, etc. can be used. For example, benzoyl peroxide, p-chlorobenzoyl peroxide, dicumyl peroxide, di-t-
Butyl peroxide, t-butyl peroxybenzoate, t-butyl peroxy-isopropyl carbonate, methyl ethyl ketone peroxide, cyclohexanone peroxide, kyumene hydroperoxide, t-butyl hydroperoxide, diisopropylbenzene hydroperoxide, p-menthane Examples include hydroperoxide. The blending ratios of the (meth)acrylic oligomer (A), fumaric acid diester (B), maleimide compound (C), and free radical polymerization initiator (D), which are the main components of the anaerobic adhesive composition of the present invention, are as follows: Although it is not specified and is blended depending on the purpose of use, the usual blending ratio is 1 to 50 parts by weight of fumaric acid diester (B) and maleimide compound to 100 parts by weight of (meth)acrylic oligomer (A). (C) in a proportion ranging from 0.1 to 50 parts by weight, and the free radical polymerization initiator (D) is the sum of the (meth)acrylic oligomer (A), the fumaric acid diester (B), and the maleimide compound (C). 0.01-5% by weight based on the amount
used at a rate of If blended in a ratio outside this range, an anaerobic adhesive composition with excellent performance as described above may not be obtained. Known accelerators used for the purpose of accelerating anaerobic polymerization, such as benzyl sulfimide and secondary or tertiary organic amines, may be appropriately used in the composition of the present invention. In addition, appropriate amounts of phenolic and quinone polymerization inhibitors, known stabilizers such as oxalic acid and ethylenediamine/tetraacetate, silane coupling agents, titanium coupling agents, colorants, thickeners, thixotropic agents, and plasticizers, etc. It is also possible to add. Furthermore, when applying ultraviolet curing, known photopolymerization initiators such as benzoin, benzyl, benzoin alkyl ether, benzophenone, acetophenone, etc. may be effectively used. (Effects of the Invention) The anaerobic adhesive composition of the present invention has a viscosity that can be easily adjusted to an appropriately low level for good workability, is fast curing, and has excellent heat resistance and flexibility when cured. Because it has excellent properties, it can be applied in a wide range of fields, including fixing threaded parts of bolts and nuts, adhesion of electrical and electronic parts, and adhesion of automobile parts, including the use of light curing such as ultraviolet rays. be. Furthermore, the anaerobic adhesive composition of the present invention has excellent flexibility in the cured product, so in the case of short-curing adhesives where impact force is applied, for example, when bonding a motor case and ferrite, cracks, cracks, No problems such as peeling occur. Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited by the Examples. In addition, parts in the examples are parts by weight, and % is weight %. Note that performance tests for each adhesive were conducted in the following manner. (1) Adhesion start time After applying the adhesive composition onto the thread of an M10 bolt, screwing in the nut and fixing it without applying any tightening torque, leave it at 23°C, and the nut will start to tighten by the start of adhesion. The time it took for the robot to stop moving by hand was measured. (2) Breaking torque strength Bolts and nuts fixed by applying an adhesive composition in the same manner as the adhesion start time measurement test were heated at 23°C.
After leaving it for 24 hours, use a torque wrench to return it.
The torque strength when it first started moving was measured and was defined as the breaking torque strength. (3) Escape torque strength After measuring the breaking torque strength, the torque strengths of 1/4, 1/2, 3/4, and 4/4 rotations were similarly measured, and the average value thereof was determined as the escape torque strength. (4) Heat Resistance Strength Similar to the breakout torque strength test, fixed and cured nuts were heated at 180°C for 6 hours, and then the breakout torque strength was determined in the same manner in the heated state to determine the heat resistance strength. (5) Workability The ease of handling the adhesive composition, including during preparation and use, was expressed in three grades: ○, △, and ×. (6) Impact test After applying an anaerobic adhesive composition to one side of a 0.5 mm thick steel plate, a 25 μ thick polyester film was pressed onto the coated surface and cured in a nitrogen atmosphere. Impact test (1Kg load - 50cm)
Apply a shock to the adhesive and observe the condition of the adhesive film. ○: No abnormality △: Slight cracking ×: Cracking, reference example of cracking 1. 152 parts of tetrahydrophthalic anhydride, 86 parts of methacrylic acid, and 2.4 parts of triethylamine were placed in a glass flask equipped with a stirrer and a dropping funnel. in,
The internal temperature was raised to 80°C. Next, 128 parts of propion oxide was added dropwise from the dropping funnel over 5 hours and the temperature was maintained until the acid value became 1 or less.
It was distilled off under the conditions of g. 0.1 part of dibutyltin dilaurate was added to 100 parts of the obtained reaction product, and 23 parts of 2,4-tolylene diisocyanate was added dropwise over 1 hour under an air atmosphere while maintaining the internal temperature at 40°C. After the dropwise addition, the internal temperature was raised to 60°C and maintained at the same temperature for 3 hours to complete the reaction, and the viscosity at 25°C was approximately
Urethane dimethacrylate (1) of 1500 poise was obtained. Example 1 An anaerobic adhesive composition of the present invention was prepared using the following formulation and a performance test was conducted. Urethane dimethacrylate (1) 65 parts N-(o-chlorophenyl)maleimide 25 parts Diisopropyl fumarate 10 parts Cumene hydroperoxide 1 part o-benzsulfimide 0.5 part N,N-dimethylaniline 0.5 parts Shown in the table. Comparative Example 1 A comparative anaerobic adhesive composition was prepared in the same manner as in Example 1, except that diisopropyl fumarate was not used and urethane dimethacrylate (1) was changed to 75 parts. I conducted a test. The test results are shown in Table 1. Comparative Example 2 Example 1 except that diisopropyl fumarate in Example 1 was replaced with isopropyl acrylate.
A comparative anaerobic adhesive composition was prepared in the same manner as above, and a performance test was conducted. The test results are shown in Table 1. Example 2 An anaerobic adhesive composition of the present invention was prepared using the following formulation and a performance test was conducted. Urethane dimethacrylate (1) 70 parts Ethylmaleimide 25 parts Dibutyl fumarate 5 parts Cumene hydroperoxide 1 part o-benzsulfimide 0.5 part 6-methylquinoline 0.5 part Oxalic acid 0.005 part The test results are shown in Table 1. Example 3 An anaerobic adhesive composition of the present invention was prepared according to the following formulation and a performance test was conducted. Dimethacrylate of 3 moles of bisphenol A ethylene oxide adduct 67 parts Cyclohexylmaleimide 25 parts Diisopropyl fumarate 8 parts Cumene hydroperoxide 1 part o-benzsulfimide 0.5 part N,N-dimethylaniline 0.5 part Shown in the table. 【table】

Claims (1)

[Claims] 1 (meth)acrylic oligomer (A) having one or more (meth)acryloyl groups in one molecule, fumaric acid diester (B), general formula (However, in the formula, R ₁ and R ₂ are each independently hydrogen, halogen, an alkyl group having 1 to 15 carbon atoms, an aryl group, or a substituted aryl group, and R ₃ is hydrogen,
Alkyl group having 1 to 15 carbon atoms, cycloalkyl group,
It is an aryl group or a substituted aryl group. ) An anaerobic adhesive composition comprising a maleimide compound (C) represented by (C) and a free radical polymerization initiator (D).