JPH05302613A - Fastener - Google Patents

Abstract

PURPOSE:To improve simplicity and security of operation in a parts assembling fasner by coating a screw with a polymer which has 2-sulfoethylacrylate or the like as a main component, applying a 2-pack adhesive which is contained in a microcapsule, and thereby improving and stabilizing fixing power. CONSTITUTION:A part of a screw is at least coated with a homopolymer having as a main component 2-sulfoethylacrylate or 2-sulfoethylmethaacrylate, such as 2-sulfoethylmethaacrylate having a polymerization degree of 100 to 1000. At least either one component of adhesive which contains two components for curing though their contact is housed in a microcapsule and applied to the coated screw. One of the component of the adhesive is acrylic monomer other than the homopolymer for coating, such as methyl (metha) acrylate, while the other is polymerization starting material such as peroxide. The polymer dissolved in an organic solvent for application to the screw, and then evaporated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for assembling various parts and the like, and fixing fasteners, that is, bolts, nuts, and the like, in which a screw portion is precoated with an adhesive that provides a momentary sealing engagement between engaging surfaces at the time of fastening. It relates to machine screws and the like. By using the fastener, a simple and strong fastening portion is formed, the reliability of the fastening work is improved, and stable assembly work can be performed.

[0002]

2. Description of the Related Art Conventionally, an adhesive which causes a curing reaction when two components come into contact with each other, one component is encapsulated in a microcapsule, and the other component is left as it is, and the two components are mixed together. Alternatively, a tightening bolt or nut in which a screw portion is pre-coated with an adhesive (hereinafter referred to as “microcapsule adhesive”) obtained by adding a film-forming substance to the adhesive is known.

[0003]

However, the above-mentioned microcapsule adhesive pre-coated on the thread portion, particularly the microcapsule adhesive containing an acrylic monomer, is easily peeled off from the surface of the screw at the time of fastening, For this reason, the adhesive is not sufficiently filled between the engaging surfaces, and the sealing engagement is apt to be incomplete. Therefore, the precoated tightening bolts or nuts have low fastening strength and large variations. It was difficult to supply it to users as a product of stable quality.

[0004]

The present invention is a polymer having 2-sulfoethyl acrylate or 2-sulfoethyl methacrylate as a main component (hereinafter referred to as "sulfoethyl (meth) acrylate polymer"), and has a threaded portion. Of at least one of the adhesives, wherein at least one component of the adhesive that causes a curing reaction by the contact of the two components is coated on the coated threaded portion with an adhesive. It is about Fuana. Hereinafter, the ingredients contained in the microcapsules are referred to as “A
The agent "and other components are called" agent B ".

Examples of the sulfoethyl (meth) acrylate polymer include homopolymers of 2-sulfoethyl acrylate or 2-sulfoethyl methacrylate monomers, random copolymers containing these monomers as main components, and block copolymers. Examples thereof include coalesce or graft copolymer. Among these, a homopolymer of 2-sulfoethyl methacrylate monomer having a degree of polymerization of 100 to 1000, or 50 of the constituent components.
A random copolymer comprising at least 2% by weight of 2-sulfoethyl methacrylate monomer is preferable because it has good stability during polymerization, and is a bulk polymerization method without using a polymerization aid such as a catalyst, a dispersant or a stabilizer. The one obtained in (1) is more preferable.

The sulfoethyl (meth) acrylate polymer is dissolved in an organic solvent having a large polarity and applied to the screw portion,
After that, the screw portion can be coated by evaporating the solvent. Examples of the organic solvent include dimethyl sulfoxide, tetrahydrofuran, dimethylformamide, acetonitrile and the like. The preferred concentration of the polymer solution is 0.2 to 10% by weight. 0.2% by weight
If the amount is less than the above, a large amount of the solution must be used in order to obtain a sufficient effect, resulting in a long drying time. While 10
When the content exceeds the weight%, the viscosity increases and coating becomes difficult, which is not preferable.

The preferable amount of the solution applied to the threaded portion is, for example, 0.001 to 0.05 g (solid content conversion) for a 10 mm diameter bolt. If it is less than 0.001 g, it is difficult to obtain a sufficient effect of the sulfoethyl (meth) acrylate polymer, and if it exceeds 0.05 g, the resistance torque during fastening of the fastener becomes too large, which is not preferable. As a coating method, an ordinary dipping method, a roll coater method, or the like can be used. Then, when the fastener is dried with hot air at about 80 ° C., a tack-free coating film is easily formed. The coating film is tightly bound to the microcapsule adhesive to be applied in the next step, and has the effect of preventing peeling of the adhesive when fastening the bolt and nut.

The adhesive used in the present invention causes a curing reaction when two components come into contact with each other. There are various such adhesives, but acrylic monomers and / or methacrylic monomers other than 2-sulfoethyl acrylate or 2-sulfoethyl methacrylate (hereinafter referred to as “(meth) acrylate monomer”). Is used as one component, a polymerization initiator such as a peroxide is used as the other component, and a polymerization accelerator or the like is further added if necessary (hereinafter referred to as “(meth)”).
This is referred to as "acrylate adhesive". However, since the curing speed of the adhesive is large, it is preferably used.

As the (meth) acrylate monomer which is one component of this adhesive, methyl (meth) acrylate, ethyl (meth) acrylate and n-butyl (meth) are used.
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, sulfopropyl (meth) acrylate Mono (meth) acrylates such as sulfoethyl (meth) acrylate, 2-hydroxyethyl (meth) acryloyl phosphite, acetoxyethyl (meth) acrylate and methylcarbitol (meth) acrylate;
Obtained by dehydration condensation of ethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, 1,3-butanediol di (meth) acrylate, polybasic acid and polyol and (meth) acrylic acid, and polyesterification reaction. Polyester di (meth) acrylate, epoxidized bisphenol A di (meth) acrylate, ethylene glycol, diethylene glycol or triethylene glycol, and di (meth) acrylate obtained from (meth) acrylic acid and a condensate of epoxidized bisphenol A, diisocyanate Di (meth) acrylates such as polyurethane di (meth) acrylates obtained from carboxylic acid, glycol and hydroxyalkyl (meth) acrylate; further glycerin, trimethylolpropane or penta Risuritoru such as (meth) obtained from acrylic acid (meth) Compound acrylate structure comprising two or more, and the like.

Among these (meth) acrylate monomers, ethylene glycol, triethylene glycol or tetraethylene glycol di (meth) acrylate;
The adhesive strength of the di (meth) acrylate obtained from the condensate of ethylene glycol, diethylene glycol or triethylene glycol, and epoxidized bisphenol A and (meth) acrylic acid is large, which is preferable.

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

Further, as a polymerization initiator to be added to the adhesive as required, ethylene thiourea, 2-mercaptobenzimidazole, benzoylhydrazine, L-ascorbic acid, dimethylaniline, dimethyl-p-toluidine, o-sulfone. Examples thereof include benzoic acid imide and thioglycolic acid.

In a two-component reactive (meth) acrylate adhesive, a polymerization initiator is generally contained in a capsule as agent A, and the (meth) acrylate monomer and the polymerization initiator are mixed as they are as agent B. use. However, it is also possible to encapsulate the (meth) acrylate monomer as the agent A in order to make the adhesive particularly stable.

When the (meth) acrylate monomer in the present invention is not encapsulated in a capsule, it can be used as it is by physically uniformly mixing with other components constituting the (meth) acrylate adhesive. However, emulsifying in water by the method described below can reduce the risk of chemical injury,
In addition, the coatability is greatly improved, which is preferable. Specifically, if a (meth) acrylate monomer is gradually added to an aqueous solution of a surfactant or a polymer having surface activity and a number average molecular weight of about 3,000 to 100,000 under high agitation, The monomer can be easily emulsified.

At this time, a water-soluble polymer and / or a water-dispersible polymer having a film-forming ability are simultaneously added at the time of emulsification of the (meth) acrylate monomer, or added after being emulsified to obtain a product. The adhesive forms a resin film on the surface after coating, which is a so-called dry-touch coated surface, which is easy to handle and safe. Further, it has a film forming ability as described below and can emulsify a (meth) acrylate monomer,
The use of a water-soluble or water-dispersible polymer is more preferable because the target product can be obtained by a one-step method.

Surfactants capable of emulsifying (meth) acrylate monomers include fatty acid salts, alkyl sulfate salts, alkylbenzene sulfonates, alkylnaphthalene sulfonates, alkyl sulfosuccinates, polyoxyethylene alkyl sulfate ester salts. , Polyoxyethylene alkylaryl ether, sorbitan fatty acid ester, glycerin fatty acid ester, polyoxyethylene alkylamine and the like. Further, examples of the polymer having a film forming ability but having a weak surface activity action include emulsion polymers having a large hydrophobicity such as urethane resin, chloroprene polymer, butadiene-acrylonitrile copolymer, and styrene-butadiene copolymer.

Next, a polymer having a film-forming ability and capable of emulsifying a (meth) acrylate monomer in water has surface activity and a number average molecular weight of about 3,000 to 100,000 in an aqueous solution state or a water dispersion state. Polymers of, for example, acrylic acid ester resin having 20 to 50% by weight of (meth) acrylic acid unit as a constitutional unit of the copolymer, vinyl acetate resin or methyl vinyl ether copolymer, polyvinylpyrrolidone, and saponification degree 30-99 mol% of polyvinyl alcohol, ethyl cellulose, hydroxypropyl cellulose, methoxy hydroxypropyl cellulose, ethylene-maleic anhydride copolymer, water-soluble or nylon polymer soluble in a mixed solvent of water and alcohol, acrylic acid Water-dispersible polymers such as ester resin emulsions may be mentioned.

Among these polymers, the saponification degree is 30 to 9
9 mol% polyvinyl alcohol, a water-soluble or a nylon polymer which is soluble in a mixed solvent of water and alcohol, or a mixture thereof provides preferable conditions for the adhesive in the present invention.

In the emulsification of the (meth) acrylate monomer, the amount of the water-soluble or water-dispersible polymer capable of forming a film is 0.5 to 30 parts by weight based on 100 parts by weight of the (meth) acrylate monomer. It is preferable to use parts because the adhesive strength of the obtained adhesive increases. It is more preferably 2 to 20 parts by weight.

Further, it is preferable to use 50 to 250 parts by weight of water as a base with respect to 100 parts by weight of the (meth) acrylate monomer, and the obtained emulsion is 3000 at 20 rpm by a B type viscometer. ~ 8000
A viscosity of 0 cps and a diameter of the emulsified (meth) acrylate monomer oil droplets of 1 to 200 μm is preferable because the coatability by a coating machine is good.

In addition to the above (meth) acrylate-based adhesive, a two-component mixed type epoxy-based adhesive prepared by adding an epoxy resin and a curing agent therefor and, if necessary, a curing accelerator is also used in the present invention. It is possible. As an epoxy resin,
There are bisphenol A diglycidyl ether, a novolak epoxy resin obtained by condensing a novolak type phenolic resin and epichlorohydrin, a glycidyl ester obtained from a dicarboxylic acid anhydride such as phthalic anhydride or hexahydrophthalic anhydride, and the like. Triethylenetetramine, tetraethylenepentamine, N-aminoethylpiperazine, xylylenediamine, 4,4'-diaminodiphenylmethane, 2-methylimidazole, 2
-Phenylimidazole, boron trifluoride, aluminum trichloride, N, N'-dimethylpiperazine, etc. are mentioned, and one of the above components is encapsulated as agent A.

The adhesive also contains a polymerization accelerator,
A partial epoxy adduct of 2,2'-bismercaptoethyl ether or the like can be added. Further, when the epoxy resin is used as it is as the agent B, it can be used by emulsifying it as in the case of the (meth) acrylate adhesive.

As a method of encapsulating the component to be the agent A, there are a coacervation method, a submerged drying method, an interfacial polymerization method and the like, but (meth) acrylate monomer, epoxy resin, aromatic amine and aroma. In the case of a lipophilic substance such as a group peroxide, the in-situ polymerization method using a urea resin is simple and the resulting capsule body is excellent in water resistance and oil resistance, which is preferable. Specifically, a liquid or fine powdery lipophilic substance is dispersed in a urea-formalin prepolymer obtained by a methylolation reaction at pH 7.5 to 9, and then the pH is adjusted to 2
The temperature is lowered to -3 and the reaction temperature is maintained at 40 to 50 ° C, and the resulting polymer is encapsulated while being deposited on the surface of oil droplets or fine powder of the above substance by the methyleneation reaction.

On the other hand, in the case of a hydrophilic substance such as an aliphatic amine, a method of performing coacervation in a hydrophobic solvent is preferable. As an example, there is a method in which a core substance is dispersed in a heated solution of ethyl cellulose dissolved in cyclohexane and then cooled, and ethyl cellulose is precipitated around the core material.

The particle size of the capsule is 10 because of the stability when mixed with the agent B and the necessity of breaking the capsule during the bonding operation.
˜100 μm is preferable, and the content of the agent A in the capsule is preferably 10 to 60% by weight.

Further, for the purpose of modifying the adhesive, various (meth) acrylate monomers are added in an amount of 1 to 30 μm in order to appropriately reduce the escape torque when the bolts and nuts are fastened.
A powder that is encapsulated in a spherical capsule body having a diameter can be mixed in the adhesive.

The microcapsule adhesive is oily as it is, and when it is aqueous, it is sufficiently stirred to give a uniform suspension state, so that a screw portion coated with a sulfoethyl (meth) acrylate polymer, In particular, it can be evenly applied to the root of the screw. Examples of the coating method include a roll coating method and a dipping method.

The preferable coating amount is, for example, 0.1 to 0.5 g (solid content conversion) in the case of a bolt having a diameter of 10 mm. 0.
If it is less than 1 g, the fixing force at the time of fastening is not sufficient, while 0.5
Even if it exceeds g, the fastening force does not increase so much, and conversely, excess adhesive tends to peel off at the time of fastening, which is not preferable.

The blending ratio of agent A and agent B in the adhesive is
The conditions adopted in the field of conventional two-component mixed adhesives may be followed.

For the purpose of improving the properties of the adhesive, for example, as a film-forming polymer for protecting the surface of the precoat layer, polyvinyl alcohol, partially saponified polyvinyl alcohol, water-soluble nylon, polyvinyl butyral or vinyl chloride-vinyl acetate is used. Copolymers and the like; talc, silica, alumina or calcium carbonate or the like in order to impart thixotropic properties; and chlorophyll compounds, copper phthalocyanine compounds, hydroquinone, in order to maintain the pot life of the precoat layer, Hydroquinone monomethyl ether, 2,4-dinitroanisole or 2,
6-Ditert-butyl p-cresol and the like can be added to the adhesive.

[0031]

In the fastener of the present invention, the microcapsule-like adhesive does not separate from the screw at the time of fastening, and the reactive adhesive is filled between the engagement surfaces of the bolt and the nut, so that the curing reaction is efficiently induced. Therefore, a strong fastening with no variation is thereby formed. This means that the sulfo group of the sulfoethyl (meth) acrylate polymer has good adhesion to the metal surface of the fastener, that the ethyl (meth) acrylate polymer part adheres evenly to the adhesive, and the strength of the polymer itself. It is thought that it is high and does not cause collapse or destruction due to impact.

[0032]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples below. The adhesion performance of the bolt coated with the microcapsule adhesive was measured by the following test method.

(Coating of Adhesive on Bolts) Yellow Chromate with 10 mm Diameter and 40 mm Length and Stainless Steel (SUS30)
To the threaded portion of the bolt consisting of 4), 0.2 g of adhesive (solid content conversion) was uniformly applied over a width of 15 mm. In the case of water-based adhesive, it is dried at 80 ° C for 20 minutes to form a resin film without tack, and when it is oil-based, it is used as it is to obtain an adhesive tightening type bolt with the adhesive applied. It was

(Adhesion test) Tighten a nut to the above-mentioned coated bolt with a torque of 300 kg weight / cm, and make it 23 ° C.
The starting return torque after standing for 24 hours was measured, and the average value and standard deviation of 10 measured values were calculated.

Example 1 (Formation of a film of a sulfoethyl (meth) acrylate polymer) A 2-sulfoethyl methacrylate homopolymer (number average degree of polymerization: 400) obtained by non-catalytic bulk polymerization was dissolved in dimethyl sulfoxide, A 5% by weight solution of the polymer was obtained. Apply 0.1 g of the solution to the threaded portion of the bolt, and
And dried for 20 minutes.

(Encapsulation of Agent A) A capsule body having benzoyl peroxide as a core material and urea resin as a wall film was prepared by the following method. 3 in 1 liter flask
350 g of 7% by weight aqueous formalin solution, 131 urea
g and 1.7 g of triethanolamine were charged, and the temperature was 70 ° C.
With a propeller-type stirrer, the mixture was stirred at 300 rpm for 2 hours and reacted to obtain a urea resin prepolymer.

Then, 609 g of the above prepolymer aqueous solution and 609 g of pure water were charged into a 2 liter beaker at room temperature, and the pH was adjusted to 2.6 by adding a 1N sulfuric acid aqueous solution. Then, fine powder of benzoyl peroxide (average particle size) 20
(μm) 12.8 g was added, the temperature was raised to 40 ° C., the mixture was reacted with a homogenizer at 4000 rpm for 6 hours, then the number of stirring was reduced to 300 rpm using a propeller-type stirrer, and the reaction was performed for 14 hours. Continued.

The resulting slurry was neutralized with a 1N aqueous solution of caustic soda, washed with pure water and methanol, and tray-dried at 40 ° C. As a result, 25% by weight of benzoyl peroxide was contained and urea resin was added. Particle size for wall membrane 20 to 50
51 g of a capsule having a size of μm was obtained.

(Preparation of Agent B) 860 g of pure water and 100 g of Gohsenol GM-14 (partially saponified polyvinyl alcohol having a saponification degree of 86 mol% and an average degree of polymerization of 1400, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) in a 2-liter beaker. To prepare an aqueous solution. After that, 650 with a propeller type agitator
Under stirring at rpm, NK BPE-200 {2,2
-Bis [4- (methacryloxydiethoxy) phenyl] propane, manufactured by Shin-Nakamura Chemical Co., Ltd.} 1000 g was added over 10 minutes with a separating funnel, and dimethyl-p was added.
-Toluidine 10 g was added and stirring was continued for 1 hour to obtain an aqueous emulsion. This emulsion has emulsified particles having a particle size of 2 to 6 μm and is 8000 at 6 rpm in a B type viscometer.
It had a viscosity of cps.

(Preparation of Adhesive) 50 g of encapsulated agent A and 800 g of agent B (solid content 450)
g) was put into a 1 liter beaker and stirred with a homogenizer at 2000 rpm for 5 minutes to obtain an aqueous adhesive.

(Adhesiveness test) The starting return torque when the adhesive liquid prepared above was applied to a bolt having a film of a sulfoethyl (meth) acrylate polymer formed thereon according to the above-mentioned method was evaluated as described above. When measured according to the method, the yellow chromate bolt has an average value of 460 kg
cm, the standard deviation value was 5 kg weight · cm, and there was no peeling of the adhesive at the time of fastening. With the stainless steel bolt, the average value was 420 kg-cm and the standard deviation value was 7 kg-cm, and there was no peeling of the adhesive at the time of fastening.

Comparative Example 1 An adhesion test was conducted under the same conditions as in Example 1 except that the coating of the sulfoethyl (meth) acrylate polymer was not formed in Example 1 and the adhesive was directly applied to the bolt. The average value of the yellow chromate bolts was 350 kg weight · cm, and the standard deviation value was 65 kg weight · cm, and the peeling of the adhesive at the time of fastening was 6 out of 10 bolts. With the stainless steel bolts, the average value was 320 kg weight · cm, and the standard deviation value was 60 kg weight · cm, and the peeling of the adhesive at the time of fastening was 7 out of 10 bolts.

Example 2 (Formation of film of sulfoethyl (meth) acrylate polymer) The same procedure as in Example 1 was carried out to obtain a bolt having a film of the polymer.

(Encapsulation of Agent A) By the following method, a capsule body having epoxy resin Epicoat 828 (manufactured by Shell Chemical Co., Ltd.) as a core material and urea resin as a wall film was prepared. In a 2 liter beaker, 609 g of the prepolymer aqueous solution synthesized in Example 1, 609 g of pure water and Epicoat 82
8 128g was charged and it was 5000rpm with a homogenizer.
After stirring, the pH was adjusted to 2.6 with 1N sulfuric acid at 40 ° C.
The temperature was raised to 0, stirring was continued, and the reaction was performed for 10 hours. As a result, the particle size is 10 to 30 μm and the epoxy resin content is 50
256 g of a capsule body with a weight% was obtained.

(Agent B) Triethylenetetramine was used.

(Preparation of Adhesive) 200 g of the encapsulated agent A, 15 g of agent B, butyral resin B obtained above
MS (manufactured by Sekisui Chemical Co., Ltd.) 12 g, toluene 21
5 g and 215 g of ethanol were put into a 1 liter beaker and stirred with a homogenizer at 2000 rpm for 5 minutes to obtain a lacquer-like adhesive.

(Adhesiveness Test) The starting return torque when the adhesive liquid prepared above was applied to a bolt having a film of a sulfoethyl (meth) acrylate polymer formed thereon according to the above-mentioned method was evaluated as described above. When measured according to the method, the yellow chromate bolt has an average value of 440 kg
cm, the standard deviation value was 5 kg weight · cm, and there was no peeling of the adhesive at the time of fastening. With the stainless steel bolt, the average value was 420 kg-cm and the standard deviation value was 7 kg-cm, and there was no peeling of the adhesive at the time of fastening.

[0048]

In the fastener of the present invention, the microcapsule adhesive is firmly adhered to the thread portion of the fastener, and therefore the adhesive is not peeled off at the time of fastening and the bolt
The reactive adhesive is filled between the nut engaging surfaces, and the curing reaction is efficiently performed. When the fastener of the present invention is used, it is possible to form a fastening portion having a strong fixing force and a small variation in the force, and it is possible to improve the simplicity and reliability of the fastening operation of the fastener.

Claims (1)

[Claims] 1. 2-Sulfoethyl acrylate or 2-
A polymer whose main component is sulfoethyl methacrylate,
A fastener that covers at least a part of the screw part,
A fastener formed by applying an adhesive agent, in which at least one component of an adhesive agent that causes a curing reaction when two components come into contact with each other, is encapsulated in microcapsules.