JP2970895B2 - Primer type acrylic adhesive for precision parts assembly - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a primer-type acrylic adhesive for assembling precision parts, and more particularly to a primer-type acrylic adhesive used for assembling precision parts such as small motors.

[0002]

2. Description of the Related Art Conventionally, fitting parts such as bearings and pulleys have been assembled by a mechanical fastening method such as press fitting or shrink fitting. However, press-fitting or shrink-fitting parts require precision processing or special processing, and have a problem that the production cost is increased due to the complexity of assembly work and the like.

[0003] In recent years, there has been no need for high-precision parts.
Assembling parts using acrylic anaerobic adhesives have been replaced by mechanical anaerobic adhesives because of the ease and speed of assembly work and the excellent durability. Bonding of precision fitting parts that require precision and speed, such as hard disks and floppy disks of personal computers, V
It is widely used for bonding small shaft motors such as stepping motors, DC motors, servo motors, and spindle motors used in drive devices for TRs, CD players, OA equipment, etc. to rotors, pulleys, bearings, etc. Have been.

However, when an anaerobic adhesive is used,
Although the part where the air in the gap of the fitting part is blocked is hardened, the protruding part remains forever without hardening,
There is a problem in that it flows out during use and contaminates other parts, or sticks when it enters a bearing.

In order to solve this problem, an ultraviolet-curable anaerobic adhesive has been developed in which the gap is anaerobically cured, and the protruding portion is cured by irradiating ultraviolet rays.
However, this UV-curable anaerobic adhesive requires an expensive UV irradiator, and depending on the structure of the assembled parts, UV irradiation may not be possible. Furthermore, although it cures when irradiated with ultraviolet light, it generally does not reach complete curing, and uncured monomers and photodecomposition products of photoinitiators are included in the cured product. Therefore, when an ultraviolet-curing anaerobic adhesive is used to assemble precision equipment parts that require high performance, the residual monomers and decomposition products of the photoinitiator are generated as outgas during use and other precision When used for bonding, for example, HDD motor parts, there is a problem that outgas adheres to the read / write head and causes serious troubles such that reading and writing become impossible.

[0006]

SUMMARY OF THE INVENTION The present invention has the advantage of good workability and durability when fitting parts are assembled using a conventional anaerobic adhesive or a UV-curable anaerobic adhesive. It is an object of the present invention to provide a primer-type acrylic adhesive for assembling precision parts, which solves the problem that the protruding portion is not cured and the problem of outgassing, which is observed when using the adhesive without damaging it. And

[0007]

Means for Solving the Problems The present inventors have studied to solve the above problems in assembling precision parts using an anaerobic adhesive or an ultraviolet-curing anaerobic adhesive, and as a result, have found that precision parts By using a primer type acrylic adhesive of a specific composition for the assembly of parts, it is possible to assemble parts in a very short time, and also to completely cure the overflowed parts, causing uncured adhesive or outgas It has been found that the occurrence of elimination is eliminated, and the present invention has been completed.

That is, according to the present invention, there is provided a first liquid containing a polymerizable (meth) acrylic monomer, an acidic phosphorus compound and an organic peroxide, and a second liquid containing a vanadium compound as a reducing agent. The present invention provides a primer-type acrylic adhesive for assembling precision parts.

The primer type adhesive of the present invention is a curing accelerator containing a polymerizable (meth) acrylic monomer, a main agent containing an acidic phosphorus compound and an organic peroxide, and a reducing agent (a vanadium compound) called a primer. And a solution.

The polymerizable (meth) acrylic monomer contained in the first liquid of the primer-type acrylic adhesive for assembling precision parts of the present invention includes alkyl (meth) acrylate, phenoxyethyl (meth) acrylate, and cyclohexyl. (Meth) acrylate, tetrahydrofurfuryl (meth) acrylate, hydroxyalkyl (meth) acrylate, poly (meth) polyhydric alcohol
Examples include acrylate, epoxy (meth) acrylate, urethane (meth) acrylate, and di (meth) acrylate of an alkylene oxide adduct of bisphenol A or bisphenol S.

The organic peroxides include hydroperoxides such as cumene hydroperoxide and diisopropylbenzene hydroperoxide, and peroxyesters such as t-butylperoxybenzoate and t-butylperoxylaurate. Peroxy ketals such as 2,5-di-tert-butylperoxy-3,3,5-trimethylcyclohexane, and ketone peroxides such as ethyl acetoacetate. The content of the organic peroxide in the first liquid is 0.1 to 10% by weight, preferably 1 to 5% by weight.

On the other hand, examples of the vanadium compound as a reducing agent contained in the second liquid include vanadium acetylacetonate, vanadyl acetylacetonate, vanadyl stearate, vanadium propoxide, vanadium butoxide, vanadium pentoxide and the like. These include thiourea compounds such as ethylene thiourea, acetyl thiourea and benzoyl thiourea, saccharin, α, α-dipyridyl, ascorbic acid, barbituric acid, acetylacetone, α-hydroxyacetone, dihydroxyacetone, acetoin, benzyl chloride, p It may be used in combination with other reducing agents such as toluenesulfonyl chloride, condensates of aldehydes and amines. The content of the vanadium compound or the copper compound in the second liquid is 0.01 to 10
%, Preferably 0.1 to 5% by weight.

The vanadium compound is usually used by dissolving it in an organic solvent, a plasticizer, or a liquid reducing agent.

In the primer-type acrylic adhesive of the present invention, the curing properties of the adhesive are improved by further adding an acidic phosphorus compound to the first liquid.

Examples of the acidic phosphorus compound include monomethyl phosphate, dimethyl phosphate, monoethyl phosphate, diethyl phosphate, mono-β-chloroethyl phosphate, di-β-chloroethyl phosphate, monoethoxyethyl phosphate, diethoxyethyl phosphate, and phenyl phosphate. , An alkyl group in a molecule such as diphenyl phosphate, a halogenated alkyl group,
Acidic phosphoric ester containing an alkoxyalkyl group or an aryl group, mono (meth) acryloyloxyethyl phosphate, di (meth) acryloyloxyethyl phosphate, mono (meth) acryloyloxypropyl phosphate, di (meth) acryloyloxypropyl phosphate, etc. Acid phosphoric acid esters containing a (meth) acryloyloxy group in the molecule, phosphonic acids such as phenylphosphonic acid and diphenylphosphonic acid, acidic pyrophosphate esters such as ethyl pyrophosphate and dibutyl pyrophosphate, and further phosphoric acid and phosphorous acid Examples include phosphorus oxyacids such as acids, hypophosphorous acid, pyrophosphoric acid, and polyphosphoric acid. The content of the acidic phosphorus compound is 0.1 to 20% by weight, preferably 0.5 to 10% by weight in the first liquid and / or the second liquid.

The primer-type acrylic adhesive for assembling precision parts of the present invention is a thickener such as a thermoplastic resin or rubber;
A substance containing a thixotropic agent, a colorant, a polymerization inhibitor, etc. may be used.

When assembling a precision fitting part using the primer type acrylic adhesive for precision part assembly of the present invention, for example, a first liquid is applied to one of the fitting parts and a second liquid is applied to the other. After that, the gap between the fitting parts is filled with an adhesive by fitting the two fitting parts into a predetermined position, and the adhesive is left at room temperature or under heating, and the adhesive and the protrusion in the gap between the fitting parts are filled. The cured adhesive is completely cured. The protruding portion is sufficiently effective even at room temperature, but is desirably heated to speed up the operation. As the heating temperature, a temperature within a range in which the precision parts are not adversely affected by heat is applied.

[0018]

The primer type acrylic adhesive for assembling precision parts of the present invention is cured by the action of a redox catalyst system formed between the organic peroxide in the first liquid and the vanadium compound in the second liquid. Since the process proceeds promptly and completely, extremely excellent performance can be exhibited particularly in assembling precision parts that require assembly in a short time, hardening of the protruding portion, suppression of outgas, and the like.

[0019]

The present invention will be described in more detail with reference to Examples and Comparative Examples. In addition, the measurement of physical properties etc. was performed by the method shown below. The use ratios of the components in Table 1 and Comparative Examples are shown in parts by weight. <Set time / adhesive strength> 3m inner diameter on 3mmφ aluminum shaft coated with adhesive
Insert an iron bearing of mφ and leave it at 23 ° C.
The time at which the punching strength reached 5 kg was defined as the set time, and the punching strength after standing for 24 hours was defined as the adhesive strength. <Curability of Extruded Part> The adhesive applied to the iron plate was fitted, and it was assumed that the adhesive was extruded from the gap between the parts. <Outgas> As an evaluation test for promoting outgas generation, the adhesive was heated to 60 ° C.
The cured product was cured by heating for 4 hours at 100 ° C. and held at 100 ° C. for 10 hours to perform thermogravimetric analysis, and the outgas generation amount was evaluated from the weight reduction rate.

Examples 1 and 2 A two-part acrylic adhesive for assembling precision parts, comprising a first liquid and a second liquid having the compositions shown in Table 1, was prepared. The second liquid of this adhesive is applied to an aluminum shaft of 3 mmφ and dried, and then the first liquid is applied thereon. Then, an iron bearing having an inner diameter of 3 mmφ is inserted, and left at 23 ° C. to measure set time and adhesive strength. Was performed. Further, with respect to the adhesive obtained by applying and drying the second liquid and then applying the first liquid, the curability of the protruding portion and the outgas were measured. Table 2 shows the results.

Comparative Example 1 75 parts of tetrahydrofurfuryl methacrylate, chlorosulfonated polyethylene (Hypalon # manufactured by DuPont)
20) 25 parts, methacrylic acid 10 parts, ethylene glycol dimethacrylate 5 parts, cumene hydroperoxide 1 part, 2,6-di-tert. A two-part acrylic adhesive composed of a first liquid composed of 0.5 parts of -butyl-4-methylphenol and a second liquid composed of a condensate of butyraldehyde and aniline (Noxeller 8 manufactured by Ouchi Shinko Chemical Co., Ltd.) Prepared. The second liquid of this adhesive was applied to an aluminum shaft of 3 mmφ, and then the first liquid was applied thereon. Then, an iron bearing having an inner diameter of 3 mmφ was inserted, and the temperature was adjusted to 23 ° C.
And set time and adhesive strength were measured. Further, with respect to the adhesive to which the first liquid was applied after applying the second liquid, the curability of the protruding portion and the outgas were measured. Table 2 shows the results.

Comparative Example 2 70 parts of hydroxypropyl methacrylate, 30 parts of dimethacrylate of bisphenol A ethylene oxide 2 mol adduct, 15 parts of acrylic polymer (Dianal BR75 manufactured by Mitsubishi Rayon Co., Ltd.), 1 part of o-benzoixulfimide, N , N-dimethyl-p-toluidine 0.3
Part, cumene hydroperoxide 2 parts, anaerobic adhesive consisting of p-benzoquinone 0.02 parts and anaerobic curing promoting primer consisting of 0.3 parts of vanadyl acetylacetonate and 1,1,1-trichloroethane. . Using the anaerobic adhesive and the primer, set time, adhesive strength, curability of the protruding portion, and outgas were measured. However, the outgas was measured without curing after heating at 60 ° C. for 4 hours. Table 2 shows the results.

Comparative Example 3 Urethane acrylate (UN1255 manufactured by Negami Industry Co., Ltd.)
50 parts, hydroxyethyl methacrylate 50 parts, dimethylbenzyl ketal 3 parts, o-benzoixulfimide 1 part, N, N-dimethyl-p-toluidine 0.3
Parts, cumene hydroperoxide 2 parts, oxalic anhydride 0.
005 parts of an ultraviolet-curable anaerobic adhesive was prepared. Using this ultraviolet-curable anaerobic adhesive, set time, adhesive strength, curability of the protruding portion, and outgas were measured. However, the curability of the protruding part is 100 mw / c using a high pressure mercury lamp of 80 w / cm.
It was measured by irradiating ultraviolet rays of m ^2. The outgas was measured for a cured product which was irradiated with ultraviolet rays for 16 seconds and further heated at 60 ° C. for 4 hours. Table 2 shows the results.

[0024]

[Table 1]

[0025]

[Table 2]

As is clear from Table 2, when the anaerobic adhesive containing no acidic phosphorus compound is used, the protruding portion is not cured at all, and when the ultraviolet-curing anaerobic adhesive is used, ultraviolet rays are not applied. The protruding part was cured by irradiation, but there was much outgas. Further, when a two-component acrylic adhesive other than the present invention was used, all of the set time, the curability of the protruding portion, and the outgassing could not be satisfied. However, when the primer-type acrylic adhesive for precision parts assembly of the present invention is used, a set time equal to or less than that of the anaerobic adhesive is exhibited, and assembling can be performed in a short time, and the protruding portion is also hardened. And outgassing was very low.

[0027]

The primer type acrylic adhesive for assembling precision parts according to the present invention is not hardened at the protruding portion, which is observed in the assembly of precision parts using a conventional anaerobic adhesive or a UV-curable anaerobic adhesive. This two-part acrylic adhesive can be used to assemble precision-fitted parts in a very short time. Since it is completely cured, it is possible to exhibit an excellent effect that troubles caused by generation of uncured adhesive or outgas can be prevented.

 ────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hidemi Doi 1515 Nakatsucho, Marugame-shi, Kagawa Prefecture Okura Industry Co., Ltd. (56) References JP-A-5-125331 (JP, A) JP-A-4-149290 ( JP, A) JP-A-62-185772 (JP, A)

Claims (1)

(57) [Claims] 1. A liquid comprising a first liquid containing a polymerizable (meth) acrylic monomer, an acidic phosphorus compound and an organic peroxide, and a second liquid containing a vanadium compound as a reducing agent. Primer type acrylic adhesive for precision parts assembly.