JPH03199706A - Fastener - Google Patents

Abstract

PURPOSE:To contrive prevention of a decrease in an adhesive speed and deteriorated connecting strength by coating a thread part with 1 to 2 or more kinds of alkali metal salt or the like and applying thereto an adhesive agent in which at least one component of the adhesive agent, which causes hardening reaction by contact of two components, is contained in a microcapsule. CONSTITUTION:An adhesive agent is applied to a thread part at least one part of which is coated with a coating agent containing 1 to 2 or more kinds of silicon dioxide, alkali metal solt of silicic acid, aluminum oxide, basic carboxylic acid aluminum and alkali metal salt aluminate or the like. In this adhesive agent, hardening reaction is generated by mutual contact of two components, and the adhesive agent, at least the one component of which is contained in a microcapsule, is used. Accordingly, firm connection without unevenness and improvement of an adhesive speed are made possible by efficiently destructing the microcapsule by coating at the time of fastening.

Description

Detailed Description of the Invention (a) Purpose of the Invention [Field of Industrial Application] The present invention is used for assembling various parts, and uses an adhesive that provides an instantaneous sealing engagement between engaging surfaces when fastened. The present invention relates to fastening fasteners, such as bolts, nuts, and machine screws, which are precoated on parts.

By using this fastener, a simple and strong fastening part is formed, the reliability of the tightening work is increased, and stable assembly work can be performed.

[Conventional technology]

Conventionally, the l component of an adhesive that causes a curing reaction upon contact with 2tc is encapsulated in microcapsules, the other components are left as they are, and an adhesive made by mixing the two (hereinafter referred to as "microcapsule adhesive") is used. ),
Alternatively, a tightening bolt whose threaded portion is precoated with an adhesive in which a film-forming substance is added to the adhesive is known.

On the other hand, in order to adjust the resistance during tightening, JP-A No. 48-41155 discloses a screw pre-coated with a powder or flake-like compound having lubricating properties in the adhesive. There is.

[Problem to be solved by the invention]

However, bolts pre-coated with the above-mentioned microcapsule adhesive have the disadvantage that the capsules are not sufficiently destroyed during tightening, resulting in incomplete sealing. This has resulted in defects such as a significant decrease in fastening strength, low fastening strength, and large variations, making it difficult to supply to users as a product of stable quality.

(B) Structure of the Invention [Means for Solving the Problems] The present invention provides one or more selected from silicon dioxide, alkali metal salts of silicic acid, aluminum oxide, basic aluminum carboxylates, and alkali metal salts of aluminate. An adhesive that causes a curing reaction when the two components come into contact with the coated thread part of a fastener, in which at least a portion of the thread part is coated with two or more types (hereinafter referred to as "coating agents"). The present invention relates to a fastener coated with an adhesive in which at least one component is encapsulated in microcapsules.

Hereinafter, the ingredients contained in the microcapsules are referred to as "A agent",
The other components are referred to as "Agent B."

[Coating agent]

The coating materials used in the present invention include silicon dioxide such as colloidal silica and silica gel, alkali metal salts of silicic acid such as potassium or lithium salts of silicic acid or water glass, aluminum oxide such as alumina sol, and bases such as basic aluminum lactate. One or more selected from aluminum carboxylates and alkali metal salts of aluminic acids.

These compounds are used in aqueous solution or suspension, the preferred concentration of which is from 5 to 80% by weight.

If it is less than 5% by weight, a large amount of the aqueous solution or suspension must be used to obtain a sufficient effect, and the drying time becomes longer. On the other hand, if it exceeds 80% by weight, the viscosity increases and coating becomes difficult, which is not preferable.

The aqueous solution or suspension is applied to at least a portion of the valley of the threaded portion. A preferable application amount is, for example, 0.05 to 0.3 g (in terms of solid content) for a bolt with a diameter of 10 mm. 0.
If it is less than 0.05 g, it is difficult to obtain the sufficient effect of the coating material, and
．． If it exceeds 3g, the resistance torque when fastening the fastener becomes too large, which is not preferable.

As a coating method, a normal dipping method, a roll coater method, etc. can be used.

When the fastener is then dried with hot air or the like, a strong glass-like film is formed.

Among the above-mentioned coating materials, water glass can be applied to a part of the valley of the threaded portion and then dried under hot air at around 80"C to form a hard and brittle glass-like film that easily meets the purpose of the present invention. It is a preferred compound because it forms

Further, it is more preferable to form a thin film of a silane compound having a condensable functional group on the threaded portion before applying the coating material, since this improves the adhesion between the threaded portion and the coating material.

〔glue〕

The adhesive used in the present invention causes a curing reaction when two components come into contact with each other.

There are various types of such adhesives, but one component is an acrylic monomer and/or a methacrylic monomer (hereinafter referred to as "(meth)acrylate monomer"), and one component is a peroxide. Adhesives (hereinafter referred to as "(meth)acrylate adhesives") that contain a polymerization initiator, such as Preferably used.

The (meth)acrylate monomer that is one component of this adhesive includes methyl (meth)acrylate, ethyl (
meth)acrylate, n-butyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, tetrahydrofurfuryl(meth)acrylate, 2-hydroxyethyl(meth)acrylate, allyl(meth)acrylate, dimethylaminoethyl(meth)acrylate , glycidyl (meth)acrylate, methoxyethyl (meth)acrylate, n-butoxyethyl (meth)acrylate, sulfoprobyl (meth)acrylate, sulfoethyl (meth)acrylate, 2-hydroxyethyl (meth)acryloyl phosphite, acetoxyethyl (meth)acrylate, ) acrylate and mono(meth)acrylates such as methylcarpitol (meth)acrylate; ethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, polybasic acids Consisting of polyester di(meth)acrylate, epoxidized bisphenol A di(meth)acrylate, ethylene glycol, diethylene glycol or triethylene glycol, and epoxidized bisphenol A obtained by dehydration condensation of polyol and (meth)acrylic acid to form a polyester. Di(meth)acrylates such as di(meth)acrylates obtained from condensates and (meth)acrylic acid, diisocyanates, glycols, and polyurethane di(meth)acrylates obtained from hydroxyalkyl(meth)acrylates; further glycerin, trimethylolpropane Alternatively, compounds containing two or more (meth)acrylate structures obtained from pentaerythritol or the like and (meth)acrylic acid may be mentioned.

Among these (meth)acrylate monomers, di(meth)acrylates of ethylene glycol, triethylene glycol or tetraethylene glycol; condensates consisting of ethylene glycol, diethylene glycol or triethylene glycol and epoxidized bisphenol A; Di(meth)acrylate obtained from acrylic acid is preferable because it has a high adhesive strength when used as an adhesive.

Examples of the polymerization initiator for the (meth)acrylate monomer, which is the other component, include benzoyl peroxide, meta-toluoyl peroxide, cumene hydroperoxide, and methyl ethyl ketone peroxide.

In addition, examples of polymerization initiators that may be added to the adhesive as needed include ethylene thiourea, 2-mercabutobenzigodazole, hendiylhydrazine, L-ascorbic acid,
Examples include dimethylaniline, dimethyl-P-1 luidine, 0-sulfobenzoic acid imide, and thioglycolic acid.

In the (meth)acrylate adhesive, a polymerization initiator is encapsulated in -g (agent A), and the (meth)acrylate monomer and polymerization initiator are left as they are in Li1 (B).
used in combination (as an agent).

However, it is also possible to encapsulate (meth)acrylate monomers in order to impart particular stability to the adhesive.

When the (meth)acrylate monomer of the present invention is not encapsulated in a capsule, it can be used as it is by physically uniformly mixing it with other components constituting the (meth)acrylate adhesive. It is preferable to emulsify the composition in water using the method described below, since it reduces the risk of chemical damage and greatly improves coating properties.

Specifically, if a (meth)acrylate monomer is gradually added to an aqueous solution of a surfactant or a polymer having a surfactant and a number average molecular weight of about 3,000 to 100,000 with high stirring, the monomer can be dissolved. can be easily emulsified.

At this time, if a water-soluble polymer and/or a water-dispersible polymer having film-forming ability is added at the same time as the (meth)acrylate monomer is emulsified or added after the emulsification, the resulting adhesive forms a resin film on the surface after coating, resulting in a so-called dry-touch coated surface, making it easier and safer to handle.

In addition, when using a water-soluble or water-dispersible polymer that has film-forming ability and can emulsify (meth)acrylate monomers as described below, it is possible to obtain the desired product by the method in step 1. It is even more preferable because it can be done.

Examples of surfactants that can emulsify (meth)acrylate monomers include fatty acid salts, alkyl sulfate salts, alkylbenzene sulfonates, alkylnaphthalene sulfonates, alkyl sulfosuccinates, polyoxyethylene alkyl sulfate salts, and polyoxyethylene alkyl sulfate salts. Examples include oxyethylene alkylaryl ether, sorbitan fatty acid ester, glycerin fatty acid ester, and polyoxyethylene alkylamine.

Examples of polymers that have film-forming ability but have a weak surface-active effect include highly hydrophobic emulsion polymers such as urethane resins, chloroprene polymers, butadiene-acrylonitrile copolymers, and styrene-butadiene copolymers.

Next, a polymer having film-forming ability and capable of emulsifying a (meth)acrylate monomer in water has surface activity and a number average molecular weight of 3000 to 1 in an aqueous solution or water dispersion state.
For example, acrylic ester resins containing 20 to 50% by weight of (meth)acrylic acid units as copolymer constituent units, vinyl acetate resins or methyl vinyl ether copolymers, polyvinylpyrrolidone, saponified Polyvinyl alcohol, ethyl cellulose, hydroxypropyl cellulose, methoxy hydroxypropyl cellulose, ethylene-maleic anhydride copolymer, nylon polymer soluble in water or a mixed solvent of water and alcohol, with a content of 30 to 99 mol%; Examples include water-dispersible polymers such as acrylic acid ester resin emulsions.

Among these polymers, polyvinyl alcohol with a degree of saponification of 30 to 99 mol%, a nylon polymer that is soluble in water or a mixed solvent of water and alcohol, or a mixture thereof is used in the adhesive of the present invention. This is preferred because it provides suitable conditions.

In the emulsification of (meth)acrylate monomer, the amount of water-soluble or water-dispersible polymer with film-forming ability is (meth)
0.5 to 30 per 100 parts by weight of acrylate monomer
It is preferable to use parts by weight because the adhesive ability of the resulting adhesive increases. More preferably, it is 2 to 20 parts by weight.

Furthermore, it is preferable to use water as a base in a proportion of 50 to 250 parts by weight per 100 parts by weight of the (meth)acrylate monomer, and the obtained emulsion is measured with a B-type viscometer at 20 rpm at 3,000 to 80,000 cps. It is preferable that the oil droplet of the emulsified (meth)acrylate monomer exhibits viscosity and has a diameter of 1 to 200 μm, since it provides good coating properties with a coating machine.

In addition to the (meth)acrylate adhesive described above, a two-component mixed epoxy adhesive comprising an epoxy resin, a curing agent thereof, and, if necessary, a curing accelerator can also be used in the present invention. .

Examples of epoxy resins include bisphenol A diglycidyl ether, novolak epoxy resin obtained by condensing novolak type phenol resin and epichlorohydrin, and glycidyl ester obtained from dicarboxylic acid anhydride such as phthalic anhydride or hexahydrophthalic anhydride.
As a curing agent, triethylenetetramine, tetraethylenepentamine, N-aminoethylpiperazine, xylylenediamine, 4,4゛-diaminodiphenylmethane,
2-methylimidazole, 2-phenylimidazole,
Boron trifluoride, aluminum trichloride, or N, N”
-dimethylpiperaziz, etc., and encapsulates one of the above components (referred to as agent A).

Further, a partial epoxy adduct of 2°2'-bismercaptoethyl ether or the like may be added to this adhesive as a polymerization accelerator.

Furthermore, when the epoxy resin is not encapsulated (used as agent B), it can be emulsified and used in the same manner as the (meth)acrylate adhesive.

〔Encapsulation〕

Methods for encapsulating the component that becomes agent A include coacervation method, submerged drying method, and interfacial polymerization method.
In the case of lipophilic substances such as meth)acrylate monomers, epoxy resins, aromatic amines, and aromatic peroxides, in-situ polymerization using urea resin is simple, and the resulting capsules have excellent water and oil resistance. It has excellent properties and is desirable.

Specifically, a lipophilic substance in liquid or fine powder form at pH 7
, dispersed in the urea-formalin prepolymer obtained by the methylolation reaction of 5 to 9, and then lowered the pH to 2 to 3 and maintained the reaction temperature at 40 to 50 °C to form the above by methylation reaction. Encapsulation is performed by depositing the resulting polymer on the surface of oil droplets or fine powder of the substance.

On the other hand, in the case of a hydrophilic substance such as an aliphatic amine, a method of coacervation in a hydrophobic solvent is preferred.

For example, there is a method in which a core material is dispersed in a heated solution of ethyl cellulose dissolved in cyclohexane and then cooled to precipitate ethyl cellulose around the core material.

The particle size of the capsule is 10 to 100 μm due to stability when mixed with agent B and the need to destroy the capsule during adhesion work.
is preferable, and furthermore, the content of agent A in the capsule is 1
0 to 60% by weight is preferred.

[Adhesive] Each of the above adhesive components can be uniformly applied to the threaded portion, particularly the thread trough, by sufficiently stirring the adhesive to give a uniform suspension state.

For example, in the case of a bolt with a diameter of 10 mm, the preferred coating amount is 0.
．． 1 to 0.5 g (in terms of solid content).

If it is less than 0.1 g, the adhesion force during fastening will not be sufficient, while if it exceeds 0.5 g, the fastening force will not increase that much, and on the contrary, excess adhesive will tend to peel off during fastening, so both are preferable. do not have.

The mixing ratio of Part A and Part B in the adhesive may be in accordance with the conditions adopted in the field of commonly used two-component mixed adhesives.

In addition, for the purpose of improving the properties of adhesives, for example, as a film-forming polymer to protect the surface of the precoat layer,
Polyvinyl alcohol, partially saponified polyvinyl alcohol, water-soluble nylon, polyvinyl butyral, vinyl chloride-vinyl acetate copolymer, etc.; to impart thixotropic properties,
Amorphous fine particles such as talc, silica, alumina or calcium carbonate; and in order to maintain the pot life of the precoat layer, a phosphorophil compound, a copper phthalocyanine compound, hydroquinone, hydroquinone monomethyl ether, 2,4-dinitroanisole or 2. .6-ditertiary-butyl p-cresol and the like can be added to the adhesive.

[Effect]

In the fastener of the present invention, the microcapsules are efficiently destroyed during fastening, thereby achieving consistent and strong fastening and also exhibiting a high adhesion speed.

This is thought to be because the coating layer is broken into fine powder and sharp pieces due to friction during fastening, and this fine powder efficiently destroys the microcapsules.

Furthermore, unlike conventional porous fillers, the finely powdered coating material does not adsorb oxygen, which has a polymerization-inhibiting effect, and conversely acts as an active site for polymerization reactions, which increases adhesion speed. This is thought to be the reason for the increase.

〔Example〕

The present invention will be explained in more detail by giving Examples and Comparative Examples below.

The adhesive performance of the bolt coated with adhesive was evaluated by the following test method.

(Applying adhesive to the bolt) Apply adhesive to the threaded part of a bolt made of yellow chromate and stainless steel (SUS304) with a diameter of 10 mm and a length of 40 mm.
0.2 g (in terms of solid content) of the adhesive was applied uniformly over a 5 mm area.

In the case of water-based adhesives, dry at 80°C for 20 minutes to form a tack-free resin film on the surface; in the case of oil-based adhesives, leave it as it is, and the glue coated with adhesive is molded. got the bolt.

(Adhesion test) A nut was tightened to the above-mentioned coated bolt with a torque of 300 kg/cm, and the starting return torque was measured after being left at 23°C for 24 hours, and the average value of 10 measured values and Standard deviation values were calculated.

Example 1 (Formation of coating layer) No. 3 water glass (Si Ot/Nat O (molar ratio) =
Synthesize in 3. Water content: 15% by weight) to the threaded part of the bolt.
．． 1g of cloth was applied and dried at 80°C for 20 minutes.

(Encapsulation of Agent A) A capsule body having Hensil peroxide as a core material and a urea resin as a wall film was prepared by the following method.

In a 1ffi flask, 350 g of formalin aqueous solution with a concentration of 37% by weight, 131 g of urea and 1 part of triethanolamine were added.
．． 7 g was charged, and the mixture was stirred at 70'C for 2 hours at 300 rpm using a propeller type stirrer to react, thereby obtaining a urea resin prepolymer.

Next, 609 g of the above prepolymer aqueous solution and 609 g of pure water were placed in a beaker 21 at room temperature, and after adjusting the pH to 2.6 by adding an IN sulfuric acid aqueous solution, fine rice powder of hensyl peroxide (average particle size 20 μm) was added. Add 12.8g, raise the temperature to 40°C, and use a homogenizer to
After reacting for 6 hours under stirring at pm, the stirring speed was reduced to 300 rpm using a propeller type stirrer, and the reaction was continued for 14 hours.

The resulting slurry was neutralized with an IN aqueous solution of caustic soda,
After washing with pure water and methanol and drying on a tray at 40"C, 25% by weight of benzoyl peroxide was found.
51 g of capsule bodies having a particle size of 20 to 50 am were obtained, which contained urea resin as a film.

(Preparation of agent B) 860 g of pure water in 21 beaker, Gohsenol GM-1
4 (partially saponified polyvinyl alcohol with a degree of saponification of 86 mol% and an average degree of polymerization of 1400, manufactured by Nippon Gosei Kagaku Kogyo ■) 1
00g was prepared and made into an aqueous solution. Thereafter, under stirring at 650 rpm using a propeller-type stirring device, NK BPE-
200 (2,2bis[4-(methacryloxyjethoxy)phenyl]propane, manufactured by Shin-Nakamura Chemical Industry ■) 100
0 g was added over 10 minutes using a separatory funnel, and further 10 g of dimethyl para-toluidine was added, and stirring was continued for 1 hour to obtain an aqueous emulsion.

This emulsion had emulsified particles with a particle size of 2 to 6 μm, and a viscosity of 8000 cps at 6 rpm in a B-type viscometer.

(Preparation of adhesive) 50 g of encapsulated agent A and 8 agent B obtained above
00g (solid content 450g) was put into a 1ffi beaker and stirred for 5 minutes at 200 rpm using a homogenizer to obtain a water-based adhesive.

(Adhesion test) When the liquid was applied to a bolt coated with the above-mentioned coating material, the start-up return torque was measured according to the above-mentioned evaluation method.
cin, standard deviation value was 10 kg weight/Cm.

Also, for stainless steel bolts, the average value is 440 kg/cm
, the standard deviation value was 15 kg/cm.

Comparative Example 1 An adhesion test was conducted under the same conditions as in Example 1, except that the adhesive was applied directly to the bolt without forming a layer of coating material, and the yellow chromate bolt had an average weight of 350 kg.・cm, standard deviation value is 65 kg weight・CI
It was I+.

Also, for stainless steel bolts, the average value is 320 kg/cm
, the standard deviation value was 60 kg/cm.

Comparative Example 2 A solid obtained by drying No. 3 water glass was pulverized to obtain a powder with a particle size of 10 to 50 μm.

50 g of encapsulated parts A and B of the adhesive of Example 1
An adhesive was obtained by adding 210 g of the powder to 800 g of the adhesive. When the liquid was directly applied to the bolt and an adhesion test was conducted under the same conditions as in Example 1, the yellow chromate bolt had an average value of 340 kg cm and a standard deviation of 50 kg cm.
It was cm.

Also, for stainless steel bolts, the average value is 330 kg/cm
, the standard deviation value was 65 kg/cm.

Example 2 4M amount % of 3-hydroxypropyltrimethoxysilane
0.1 g of the dissolved methyl cellosolve solution was evenly applied to the threaded part of the bolt and dried at 80''C for 20 minutes.

Next, apply Snowtex XS (particle size 4 to 6 μm
0.4 g of silica sol containing 20% by weight of silicic anhydride; manufactured by Nissan Chemical Industries Ltd.
Dry for 0 minutes.

An adhesion test was conducted using the adhesive of Example 1 under the same conditions as Example 1, and the yellow chromate bolts had an average value of 480 kg weight and a standard deviation of Cl111 of 10 kg weight.
The average value for stainless steel bolts was 450kg/cm.
, the standard deviation value was 15 kg/cm.

Example 3 (Coating layer form I'Ii) 0.1 g of the above-mentioned No. 3 water glass was uniformly applied to the threaded portion and dried at 80° C. for 20 minutes.

(Encapsulation of Agent A) A capsule body having an epoxy resin Epicoat 828 (manufactured by Shell Chemical Co., Ltd.) as a core material and a urea resin as a wall film was prepared by the following method.

21 In a beaker, 609 g of the prepolymer aqueous solution prepared in Example 1, 609 g of pure water, and Epicoat 828 128
After adjusting the pH to 2.6 with IN sulfuric acid while stirring with a homogenizer at 500 rpm, the temperature was raised to 40°C and stirring was continued for 10 hours.

As a result, 256 g of capsule bodies with a particle size of 10 to 30 μm and an epoxy resin content of 50% by weight were obtained.

(Agent B) Triethylenetetramine was used.

(Preparation of adhesive) 200 g of encapsulated agent A obtained above, 1 agent B
5g, butyral resin BM-3 (manufactured by Block Chemical Industry ■) 1
2g, 215g of toluene and 215g of ethanol in 11
Pour into a beaker and homogenize at 200 rpm.
The mixture was stirred for 5 minutes to obtain a lacquer-like adhesive.

(Adhesion test) An adhesion test was conducted when the liquid was applied to bolts coated with the above-mentioned coating material. For yellow chromate bolts, the average value was 440 kg weight/Cl11, and the standard deviation value was 10 k.
It was g weight/cai.

Also, for stainless steel bolts, the average value is 420 kg/cm
, the standard deviation value was 15 kg/cm.

Example 4 Alumina sol 520 (positively charged alumina fine particles 2
0.4 g of a low viscosity colloid (containing 0% by weight) was uniformly applied to the threaded portion of the bolt and dried for 20 minutes at ao"c.

An adhesion test was conducted using the adhesive of Example 3 under the same conditions as Example 1, and the yellow chromate bolts had an average value of 460 kg/cm and a standard deviation of 15 kg/cai.
Met.

Also, for stainless steel bolts, the average value is 420 kg weight/ca
m, and the standard deviation value was 15 kg weight/cm.

Example 5 Aqueous solution containing 15% by weight of Taxeram G-17P (polymeric basic aluminum lactate powder; manufactured by Tamoto Kagaku ■) 0
．． Apply 5g evenly to the threaded part of the bolt and heat it at 80°C for 2 hours.
Dry for 0 minutes.

An adhesion test was conducted using the adhesive of Example 3 under the same conditions as Example 1, and the yellow chromate bolts had an average value of 440 kg/cm and a standard deviation of 10 kg/cm.

In addition, for stainless steel bolts, the average value is 410 kg weight/Cl
11. The standard deviation value was 10 kg weight/CII+.

(C) Effects of the Invention The fastener of the present invention has high adhesion speed and adhesion strength during fastening, with little variation, and improves the ease and reliability of fastener fastening work.

Claims (1)

[Claims] 1. One or more selected from silicon dioxide, alkali metal salts of silicic acid, aluminum oxide, basic aluminum carboxylates, and alkali metal salts of aluminate,
An adhesive that causes a curing reaction when the two components come into contact with the covered threaded part of a fastener whose threaded part is at least partially covered, at least one of which is encapsulated in microcapsules. A fastener made by coating.