JPH011779A - adhesive composition - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] (a) Purpose of the Invention [Field of Industrial Application] The present invention relates to a one-component adhesive, which has a particularly high adhesion speed, hardens at room temperature, has a long pot life, and The present invention relates to an anaerobic adhesive that has coatability by forming it into an aqueous composition.

Since this adhesive composition can be finished as a dryer, it is suitable as an adhesive for preventing loosening of screws or a laminating type adhesive for laminated boards.

[Conventional technology]

Conventionally, one-component room-temperature curing adhesives that harden rapidly have been anaerobically cured, mainly containing monomers having acryloyl groups and/or methacryloyl groups (hereinafter referred to as "(meth)acrylate monomers"). sexual compositions have been used.

[Problem that the invention seeks to solve]

Conventional anaerobic curable compositions are compositions that remain oily when in contact with air or oxygen and harden rapidly when removed from air or oxygen.

Therefore, prior to curing, curing accelerators such as oil-based (meth)acrylate monomers, peroxides, or amines pose a risk of chemical damage, unstable bot life, selectivity of the adhesive, or It had drawbacks such as poor coating due to inappropriate viscosity.

(b) 100 parts by weight of the constituent rate monomer of the invention, 0.2 to 3 parts by weight of the encapsulated organic peroxide, 0.02 to α5 parts by weight of the water-soluble compound having a mercapto group, and the above organic peracid. This is an adhesive composition comprising 1 to 2 parts by weight of a reducing agent n other than a water-soluble compound having a mercapto group that forms a redox system with a substance.

[(Meth)acrylate monomer atomized in water]

The method of emulsifying the (meth)acrylate monomer in the present invention is as follows.

Has surface activity in aqueous solution state and has a number average molecular weight of 30
If a (meth)acrylate monomer is gradually added to an aqueous solution of a polymer having a molecular weight of about 0.00 to 500 mm under vigorous stirring, it can be easily emulsified. By then adding a water-soluble and/or emulsifying polymer with film-forming ability, it is possible to obtain an emulsified (meth)acrylate monomer in water that can be used in the present invention.

Alternatively, when a polymer having film-forming ability and water solubility, surface activity, and high viscosity is used, the desired product can be obtained by the second method.

In the emulsification of (meth)acrylate monomer in the present invention, (meth)acrylate monocap body 100! It is preferable to use the white polymer at a ratio of 2 to 10 parts by weight and 50 to 250 parts by weight of pure water, and the produced emulsion is measured with a B-type viscometer at 20 rpm of 4,000 to 40 parts by weight.
000 cps and the diameter of the dispersed oil droplets of the dispersed (meth)acrylate monomer is 10 to 200 cps.
It is preferably μ.

The (meth)acrylate monomers used in the present invention include methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and tetrahydrofurfuryl (meth)acrylate. Acrylate, 2-hydroxyethyl (meth)acrylate, allyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, glycidyl (
Monos such as meth)acrylate, methoxyethyl(meth)acrylate, butoxyethyl(meth)acrylate, sulfopropyl(meth)acrylate, 2-hydroxyethyl acryloyl phosphite, acetoxyethyl(meth)acrylate, and methylcarpitol(meth)acrylate (meth)acrylate, or ethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, t5butanediol di(
meth)acrylate, polyester di(meth)acrylate obtained by dehydration condensation polyesterification reaction from polybasic acid, polyol and (meth)acrylic acid, epoxidized bisphenol A di(meth)acrylate, epoxidized bisphenol A and ethylene glycol or Di(meth)acrylates obtained from diethylene glycol or a condensate with triethylene glycol and (meth)acrylic acid; di(meth)acrylates such as polyethylene di(meth)acrylate obtained from diincyanate, glycol, and hydroxylalkyl(meth)acrylate; ,
Further examples include compounds containing two or more (meth)acrylate structures obtained from glycerin, trimethylolpropane, pentaerythritol, etc. and (meth)acrylic acid.

As a polymer that has film-forming ability and can emulsify (meth)acrylate monomer in water, 30% by weight of acrylic acid is used.
Acrylic acid ester resin, vinyl acetate copolymer or methyl vinyl ether copolymer polyvinylpyrrolidone having the above copolymer composition, saponification degree of 30 to 90 mok%
17) Polyvinyl alcohol, ethyl cellulose, human tetraxypropyl cellulose, methoxyhydroxyglobil cellulose, ethylene-maleic anhydride copolymer, water-soluble nylon polymer, urea-formalin polymer, or polypropylene oxide and polypropylene oxide. Examples include water-soluble polymers such as copolymers, and emulsion polymers such as acrylic acid ester resin emulsions, urethane emulsions, chloroprene polymer emulsions, and butadiene-acrylonitrile emulsions. In particular, the use of a mixture of polymers, such as the following, provides suitable conditions for the method of the present invention.

[Encapsulated organic peroxide]

Powdered or liquid organic peroxides can be easily encapsulated using a coacervation method or an interfacial polymerization method.

When using the coacervation method, a method of applying a gelatin-gum arabic film is mentioned, but in order to improve water resistance, a prepolymer of urea-formalin-melamine is present after coacervation to induce interfacial polymerization. A two-stage encapsulation method performed in succession is preferred.

In the case of a finely powdered organic peroxide, it is preferable to adopt an interfacial polymerization method, and specifically, in the urea-formalin prepolymer obtained by the methylolation reaction of I) H7, A preferred method is to suspend the organic peroxide in the solution, gradually lower the pH to 2 to 3, maintain the reaction temperature at 35 to 40°C, and encapsulate the resulting polymer while depositing it in the peroxide powder through a methylenation reaction. It is.

In the method of the present invention, the particle size of the capsules is between 20 and 100 mm due to stability during mixing with the (meth)acrylate monomer emulsified in water and the necessity of breaking the capsules during the bonding operation.
μm is preferable, and the content of peroxide in the capsule is preferably 10 to 60% by weight.

As the organic peroxide used in the present invention, hydroperoxide, ketone peroxide, dialkyl peroxide, peroxy ester, diacyl peroxide, etc. can be used, but in particular, benzoyl peroxide or meta-toluoyl peroxide is used. is preferable.

The amount of the encapsulated organic peracid used is α2 to 3 parts by weight per 100 parts by weight of the (meth)acrylate monomer. If α2 parts by weight is less than 2 parts by weight, the adhesive performance will not be exhibited, while if it exceeds 3 parts by weight, more than the appropriate amount will be mixed in as foreign matter and the adhesive performance will decrease.

[Water-soluble compound with mercapto group] (meth)
Although it is convenient to use it in a state where it is mixed with an acrylate monomer, it can of course also be used in an encapsulated state. In this case, the (meth)acrylate monomer can be easily mixed by being added at the same time in the emulsification process described above.

Specific examples of the compound include mercaptoethanol,
Examples include thiomalic acid, thioglycolic acid, thiolactic acid, α-thiobutyric acid, methylbutetheramine, and 0- or m-thiosalicylic acid.

The amount of water-soluble compound with mercapto group used is (meth)
α02 to α5 based on 100 parts by weight of acrylate monomer
．． tffi section is required. When the amount is less than 0.02 parts by weight, the adhesive composition of the present invention has no life of adhesive performance before being destroyed, and the adhesive strength during adhesive processing is low. If the amount exceeds 1 part by weight, the balance of the redox reaction mechanism will be lost and the adhesive ability will decrease, making each part unsuitable.

[Reducing agent other than a water-soluble compound having a mercapto group that forms a redox system with an organic peracid] If the compound is water-soluble, it can be used in the present invention in the same way as a water-soluble compound having a mercapto group; If it is soluble, it can be used by previously dissolving it in the (meth)acrylate monomer or by encapsulating it and mixing it into the composition.

Specific examples of such compounds include organic acid salts such as copper, cobalt, and manganese, ethylenethiourea, tetramethylthiourea, A water-insoluble mercapto compound such as 2-mercaptobenzimidazole, hydrazine, sodium 2-hydronate, L-ascorbic acid, or triethylenediamine is used. For diacyl peroxides, dimethylaniline, dimethyl-p-)luidine, diethyl-
p-Toluidine, N,N dimethyl-p-aningine, or 0-sulfobenzoic acid imide are each preferably used.

The amount of the compound used is (meth)acrylate monomer 10
α1 to 2 parts by weight are required for 0 parts by weight. 0.1
If the amount is less than 2 parts by weight, the redox reaction is weak and there is no adhesion ability below room temperature, while if it exceeds 2 parts by weight, the balance of the redox reaction mechanism will be lost and the adhesion ability will be reduced, making each of them unsuitable. It is.

[Other substances that can be employed in the adhesive composition of the present invention]

For the purpose of improving the properties of the adhesive composition, for example, to impart thixotropic properties, Merck, silica, alumina or calcium carbonate is used, and to maintain a long nabot life, hydroquinone, methylhydroquinone, 2,4-dinitroanisole or 2,6-ditertiary-butyl p-cresol can be used.

[For production]

The adhesive composition of the present invention maintains an aqueous system when applied to an adherend, and furthermore, since the dry layer contains peroxide, which is the main component of the catalyst system, is encapsulated, the adhesive composition contains (meth)acrylate monomers. The body forms an oil layer on the surface of the adherend without any curing reaction,
Moreover, the surface is formed with a drier film by the pre-existing polymer.

However, during bonding operations, simply by rubbing or applying pressure to the surface of the adherend, the capsule is destroyed and the peroxide is eluted into the (meth)acrylate monomer, and at the same time comes into contact with the reducing agent that forms redox. , a curing reaction is initiated and adhesive ability is exhibited.

In this case, the presence of a water-soluble compound having a mercapto group not only promotes the above redox reaction but also has the effect of inhibiting the polymerization of the (meth)acrylate itself before the capsule is destroyed.

The reason for this is thought to be that the water-soluble compound having a mercapto group is attached to the surface of the pre-existing polymer film at a molecular layer level, thereby suitably controlling the above redox reaction. Therefore, even mercapto compounds, which are likely to cause bad odor, can be handled odorlessly as a member of the adhesive composition.

〔Example〕

Next, examples and comparative examples will be given to further specifically explain the present invention.

Example 1 (Production of encapsulated benzoyl peroxide) In order to encapsulate benzoyl peroxide with a urea-formalin resin, a urea-formalin prepolymer was first synthesized by the following method.

1! Formalin aqueous solution with a concentration of 37% by weight in a flask 65
0? , Urea 131? , and triethanolamine t7P
was charged and reacted with stirring at 70°C for 2 hours at 5Q rpm, pH 8.1 and 20 rpm in a B-type viscometer.
A prepolymer having a viscosity of 8.3 was obtained.

The pH was brought to 2.0 by addition of 15 cc of 1N aqueous hydrochloric acid under stirring at rpm. Add 12.8 tons of benzoyl peroxide fine powder (average particle size 20 μm) and heat at 40°C.
Stirring was carried out under the conditions of 5000 rpm
The reaction was carried out under the conditions of 2000 rpm x 14 hours to obtain encapsulated benzoyl peroxide in the form of a slurry.

This powder had a urea-formalin resin coating content of 793% by weight and a polynuclear powder with an average particle size of 4 μm.

(Adjustment of adhesive composition) 2.13 Pure water 860? , Metrose 908H
30000 (methoxyhydroxypropyl cellulose,
Manufactured by Shin-Etsu Chemical Co., Ltd.) 14? Epan U108 (block copolymer of polyethylene oxide and polypropylene oxide, manufactured by Daiichi Kogyo Seiyaku ■) 10? NK BPE-200 (2,2bis[4-(methacryloxyjethoxy)phenyl]propane, manufactured by Shin-Nakamura Chemical Co., Ltd.) 1030P, dimethyl para-toluidine 5.
．． 5F, 2-mercaptoethanol 2.11, and AQ
-Nylon A-90 (water-soluble nylon, manufactured by Toshi ■) 21
? Further, the mixture was added and stirred for 2 hours to obtain an aqueous emulsion.

49.8 P of the encapsulated benzoyl peroxide (content of benzoyl peroxide 1 (L3P)) was mixed into the emulsion with stirring, and the mixture was mixed with a B-type viscometer, 2
A water-based adhesive composition with a viscosity of 8000 cps at Qrpm was obtained.

(Application of adhesive composition to bolt thread) 89 diameter, length 4
The resulting aqueous adhesive composition 0.2? was applied uniformly and dried at 60° C. for 60 minutes to form a resin film with no tack on the surface, thereby obtaining a screw type screw coated with the adhesive composition.

(Adhesion Performance and Other Evaluation Tests) t Adhesiveness Test The above-mentioned coated screw was tightened with a torque of 230 kli 1 force and 1, and after being left at 25° C. for 24 days, the start-up return torque was measured.

λ Adhesive Performance Pot Life Test After heating the above-mentioned coated screw at 40℃ for 30 days, tighten it with a torque of 23 kg/α to 23℃.
The starting return torque was measured after being left for 24 days.

3゜Heat resistance test Tighten the above coated screw to 250 with a torque of 9 times and 1, continue heating at 120℃ for 24 hours, and heat it to 120℃.
The starting return torque was measured while the engine was held at .

The results of these tests are shown in Table 1.

Examples 2 to 8 Comparative Example 1 In Example 1, a (meth)acrylate monomer, an organic peroxide, a water-soluble compound having a mercapto group, or a mercapto compound that forms a redox system with the above organic peroxide. Reducing agents other than water-soluble compounds having groups (in Table 1 [Redo.

(3) Effect of the invention The adhesive composition of the present invention retains an aqueous system when applied to an adherend, so it is easy to work with and is safe to handle. Furthermore, after drying, since the peroxide, which is the main component of the catalyst system, is encapsulated, the (meth)acrylate monomer does not undergo a curing reaction and forms an oil layer on the surface of the adherend. Since the existing polymer forms a dry film, it is suitable for storing and transporting adherends.

Claims (1)

[Scope of Claims] 100 parts by weight of a monomer having an acryloyl group and/or methacryloyl group emulsified in water with a film-forming polymer, and 0.2 to 3 parts by weight of an encapsulated organic peroxide. , 0.02 to 0.5 parts by weight of a water-soluble compound having a mercapto group, and 0.1 to 2 parts by weight of a reducing agent other than the water-soluble compound having a mercapto group that forms a redox system with the above organic peroxide. Adhesive composition.