KR970000309B1 - Adhesives for micro-capsule - Google Patents

Abstract

A microcapsule-type adhesive was manufactured by mixing the anaerobic microcapsule type adhesive and binder solution, coating and drying to give the titled adhesive. Thus, a mixture of gelatin and arabic gum as surfactant, raw material for capsule such as triisocyanate[2-ethyl-2-(hydroxy methyl)-1,3-propanediol, an adhesive monomer such as trimethylol propane triacrylate, M-methyl styrene and vinyl toluene, a reducing agent such as N,N'-dimethyl-p-toluidine, an oxidizing agent such as cumene hydro peroxide, and an organic solvent such as tetrachloroethylene and toluene were stirred at 60deg.C for 1 hour, where ethylene glycol which is the raw material for the other capsule is added to the mixture for a interfacial polymerization to give round-shaped polyurethane microcapsule.

Description

Manufacturing method of microcapsule adhesive

FIG. 1 shows that the microencapsulated anaerobic adhesive obtained in Example 2 of the present invention is coated on a bolt together with a binder.

FIG. 2 is applied to a galvanized bolt (3/8 in diameter, 1.1 / 4 in length) / nut of the microcapsule adhesive obtained in Example 2 of the present invention and a commercially available Japanese THREE BOND grade product, and fastened at 25 ° C. , After 24 hours, the adhesive strength (breakdown-torque torque) is compared.

* Explanation of symbols for main parts of the drawings

1: binder 2: microcapsules

The present invention relates to a method for preparing an adhesive by mixing, coating and drying the microencapsulated anaerobic adhesive with a binder solution, and more particularly, does not directly apply a liquid anaerobic adhesive when fixing a bolt or screw. Instead, the microcapsule is coated and dried on the use part together with the binder solution, and conveniently used. This preparation method is an organic solvent and solvent, which are internal substances of the capsule, as well as a chemical reaction between the anaerobic monomer and the oligomer in the microcapsule. It is characterized by improving the adhesive force by a combination of a solvent activation reaction between the activated binder resins.

For many years, mechanical technicians have devised a method of assembling a machine or part using bolts / nuts or screws to secure it to withstand loosening even after prolonged use. Various shapes of bolts / nuts and screws were created to complement the function.

Nevertheless, bolts / nuts and screws used in machinery or components will have less resistance to the environment applied to them over long periods of time and the bolts / nuts and screws will loosen. Here is why the bolts / nuts are loosened.

All bolts / nuts have a clearance between the bolts and nuts to allow tightening and loosening. In other words, there is a space that can move between each other.

Here, suppose the screw surface of the bolt is an inclined slope and assumes that the nut is not slipping on it by friction. When the surrounding environment provides the cause of slipping such as rotational movement or vibration related to loosening of the nut, As the bolts and gaps become larger and less friction between them, they loosen gradually. At this time, the greater the tightening force of the nut can reduce the possibility of slipping, but once the movement occurs, the tightening force helps to loosen. In general, the causes of bolt / nut loosening include shocks and internal pressures, as well as reasons for tightening of the tightened part or accompanying shrinkage and expansion of different materials.

Therefore, in order to prevent loosening of bolts / nuts or screws, the function of preventing rotation of nut or screw as well as braking of loosening should be supplemented even if loosening starts. This can be achieved by using a screw adhesive, which will fill all the gaps in the bolts / nuts, thereby preventing the nut from rotating or sideways. That is, filling the bolt / nut gap with an adhesive and hardening the adhesive, the unevenness of the bolt / nut ( The adhesive penetrates to the site, which is why it has a locking function that resists the cause of loosening from the outside.

Here, for example, a method of gluing a hydrophobic and volatile solvent in a microcapsule (US Pat. No. 4,610,937), which uses only solvent activation by a volatile solvent in a microcapsule, is used. The adhesive strength is very weak compared to the chemical reaction bonding method.

In this regard, when the internal substance of the microcapsules is filled only with monomers and initiators of adhesive components, the formation reaction of the capsule by the chemical method of interfacial polymerization is also hindered due to the high viscosity, and the physicochemical method such as core celsation or composite-core The method such as selvation also takes a complicated process and a lot of time to produce the capsule.

Therefore, in the present invention, the adhesion is enhanced by simultaneously using the solvent-activated adhesion method between the organic solvent and the capsule binder resin in the microcapsule and the chemical reaction of the anaerobic monomer.

In other words, in the present invention, the monomer, initiator, organic solvent, and the like of the adhesive component are included as the inner material of the microcapsule by the interfacial polymerization method, and the solvent-activated binder resin which can use the organic solvent inside the microcapsules is blended together. Chemical and physicochemical methods were used simultaneously.

Looking at the manufacturing process of the microcapsules according to the present invention. That is, the oil-phase in which one of the adhesive monomer, a small amount of an organic solvent, an oxidizing agent / reducing agent, and one capsule wall material A to form the capsule wall film is dissolved is added to a large amount of aqueous solution in which the surfactant is dissolved. Stirring and dispersing at a constant rate using a stirrer to form round oil-droplets containing the monomer, initiator and organic solvent of the adhesive component.

While stirring at a constant speed, the other capsule wall material B which can react with the capsule wall material A dissolved in the oil droplets is added to the aqueous solution. The capsule wall material A dissolved in the oil droplets and the capsule wall material added to the aqueous solution An interfacial polymerization reaction in which B forms a capsule wall film at the interface between the oil droplet and the aqueous solution occurs to form a microcapsule containing monomers, an initiator, an organic solvent, and the like of an adhesive component. At this time, the interfacial polymerization reaction between the capsule wall material A and the capsule wall material B proceeds sufficiently until a stable microcapsule having high mechanical strength is formed.

Then, when the aqueous solution containing the microcapsules is filtered, the capsules are entangled with each other due to the water / trace organic solvents present in the capsule wall. In order to prevent this, in the present invention, the capsules are washed with an alcohol or an aqueous alcohol solution during filtration, and microcapsules having a desired size are obtained through a process such as freeze drying or spray drying.

The microcapsules of the present invention are formed by performing the interfacial polymerization reaction between the capsule wall material A and the capsule wall material B at the interface between the oil droplet and the aqueous solution, and the characteristics of the capsule wall film are determined by the selection of the capsule wall material A and the capsule wall material B. Can vary. As a microcapsule wall component of the present invention, aminoplast, polyamide or polyurethane is preferable because the formation process of the film is fast and the film structure is dense.

In the selection of the capsule wall material A and the capsule wall material B, gelatin, urea, melamine, formaldehyde, and the like are used to form a microcapsule wall film of an aminoplast component. To form a microcapsule wall of the polyamide component, polyfunctional amines selected from 1,6-hexamethylenediamine, diethylenetriamine, tetraethylenetriamine, tetraethylenepentaamine, sebaconyl chloride, terephthaloyl chloride, and the like Dibasic acid chloride selected from among. To form a microcapsule wall of polyurethane component, diphenylmethane-4,4'-diisocyanate (hereinafter referred to as MDI), toylene-2,4-diisocyanate ( polyfunctional isocyanate selected from toylene-2,4-diisocyanate (hereinafter referred to as TDI), and polyfunctional alcohol selected from ethylene glycol, glycerol, resorcinol, and the like.

On the other hand, the binder solution used when corning the microcapsule on the bolt or screw interacts with the unit of the adhesive component, the organic solvent, etc. contained in the capsule to improve the adhesion. The preparation of the binder solution is performed as follows.

In the present invention, the oxidizing agent and the reducing agent are used as initiators of the polymerization reaction, N, N'-dimethyl-p-toluidine and the like are used as reducing agents, and cumene hydroperoxide and the like are used as oxidizing agents. Anaerobic monomers and oligomers that can be initiated by such initiators include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, lauryl (meth) acrylate, and ethylene. Glycol di (meth) acrylate, diethylene glycol di (meth) meth (acrylate), triethyleneglycol di (meth) acrylate, tetraethyleneglycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate And one or two or more selected from the derivatives, and the like, which are uniformly dissolved in the solvent used.

In addition to this, as a resin component that promotes adhesion, a carboxyl-modified vinyl chloride-vinyl acetate copolyment copolymer (hereinafter referred to as VCVA) or a hydroxy group-modified vinyl chloride-vinyl It is dissolved in a solvent using an acetate copolymer (hereinafter referred to as HVCVA).

If the resin components that promote the adhesion are not used, the bonding force to the bolt or screw is weakened, and the coated binder resin is pushed out when the nut or screw is tightened, and the adhesive strength is significantly decreased.

In addition, materials for imparting flexibility to the adhesive include polyvinylidene fluoride, fluoroelastomer of hexafluoropropene (CF ₃ -CF = CF ₂ ) polymer, chlorinated polyethylene, polyester, polyvinyl chloride, hydrocarbon polymer, poly (Vinylacetate), polyurethane, polyacrylonitrile and the like are used, which must be dissolved in the monomer or organic solvent of the adhesive component that is the inner material of the capsule.

Other components of the microcapsule adhesive include coatings, non-tackifiers that prevent the dried adhesive from sticking, coupling agents that improve the miscibility between organic polymers, curing rate regulators, fillers, and the like. This is used.

Hereinafter, the present invention will be described in detail.

For practical application of the microcapsule adhesive, a binder solution other than the microcapsule containing the adhesive component is made separately, and the microcapsules are uniformly dispersed in the binder solution dissolved in the organic solvent.

First, a microcapsule containing an adhesive component, an initiator, an organic solvent, and the like as an internal material is prepared by the above method, and a binder solution used with the same is made as follows. That is, 15-25 weight% polyester acrylate concentration and 10-25 weight% urethane acrylate are melt | dissolved in the mixed solvent which mixes toluene and the methyl ethyl ketone 1: 1 ratio. In this case, it is better to use polyester acrylate or urethane acrylate in combination than to use each alone, and the adhesive strength is lowered out of these concentration ranges.

Then, VCVA modified with carboxyl group is added at a concentration of 5 to 13% by weight based on the binder solution, and a polybutadiene-acrylonitrile copolymer (hereinafter referred to as HYNBR) is used as a coating enhancer to enhance adhesion. It may be used in combination.

If VCVA is added below 5% by weight, the adhesive strength between binder bolts and screws is weakened, and when the nuts and screws are tightened, the coated binder components are pushed out of the bolts and screws to obtain sufficient adhesive strength, whereas VCVA is 13% by weight. When added above the concentration, the binder coated on the bolt is not pushed out, but the microcapsule ratio decreases, so that the adhesive force decreases because the monomer, organic solvent, etc. of the adhesive component are relatively reduced.

As solvent-activated resin, 0.5 ~ 8% by weight of chloroprene rubber is used with respect to the binder mixture, and when it is added below 0.5% by weight, the amount of rubber that can be activated by the organic solvent inside the microcapsules is sufficient, so that sufficient adhesive strength is achieved. If the concentration is more than 8% by weight, it will interfere with the curing of the monomer of the adhesive component inside the microcapsule.

Other additives include talc, polymethyl methacrylate (hereinafter referred to as PMMA) or polyethylene powder (to provide non-tackiness, viscosity control, and filling effect so that the coated and dried adhesive does not become sticky even if touched). Melting index 4 ~ 6, particle size 30μ or less), γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, or vinyl as a coupling agent to improve the mixing between the non-glutin and the organic polymer In order to improve the low stability of the binder resin, a polymerization inhibitor such as hydroquinone or p-benzoquinone is combined with a reducing agent by using tris (2-methoxyethoxy) silane. Synergistic promoters include o-benzoicsulfimide (hereinafter referred to as SCC), benzoic acid sulfimide, acetyl thiourea, ethylene Ourea (ethylene thiour mea) and 2-mercappot benzothiazol, cobalt acetylacetonate (hereinafter referred to as CoA), cupric acetylacetonate (hereinafter referred to as CuA) Etc.), and these are mixed with sufficient stirring.

Hereinafter, the present invention will be described in detail with reference to Examples. The present invention is not limited by the Examples.

Examples 1-2

As a surfactant, gelatin and gum arabic are mixed at a ratio of 1: 0.3 and dissolved in water to prepare an aqueous solution having a concentration of 1.5% by weight. Here, as one capsule wall material, triisocyanate [2-ethyl-2- (hydroxymethyl) -1,3-propanediol and toylene-2,4-diisocyanate: 3 mol ratio of reactants] 9 mmol (calculated by functional group concentration), 3.5 g of trimethylolpropanetriacrylate, 15 g of α-methylstyrene, 5 g of vinyltoluene as monomers of the adhesive component, and N, N'-dimethyl-p-toluidine as reducing agent 6 g, cumene hydroperoxide 3.5 g, and chloroethylene 15 g / toluene 5 g were used as the organic solvent, respectively. The mixture was stirred and dispersed at 60 ° C. for 1 hour to make uniform oil droplets of the additives in the aqueous solution. After the addition of 9mmol (calculated by functional group concentration) of ethylene glycol, the other capsule wall material, into the aqueous solution of oil droplets, interfacial polymerization of the wall film-forming raw materials at the interface of the oil droplets and the aqueous solution for 2 hours at the same temperature. Reaction, round poly A shot microcapsules were prepared.

The microcapsules were sufficiently mixed with a binder solution prepared in the following manner, coated and dried on necessary parts, and subjected to an adhesion test. The results are shown in Table 1 below.

In the preparation of the binder solution, in Example 1, 20 g of polyester acrylate, 17 g of urethane acrylate, 10 g of VCVA, and 0.8 g of HYNBR were uniformly dissolved in 100 g of a mixed solvent mixed with toluene and methyl ethyl ketone in a ratio of 1: 1. Thereafter, 1.5 g of PMMA 6.5 g vinyl tris (2-methoxyethoxy) silane, 8 g of acrylic acid, 40 g of talc, 0.001 g of p-benzoquinone, 0.08 g of CuA, and 0.1 g of SCC were added and uniformly blended with a stirrer. In case 2, 2.0 g of chloropropene rubber was added in addition to the composition of Example 1.

In the adhesion test, the galvanized bolt (3/8 in. Diameter, 1/4 in.) And nut specimens are first washed and dried with methylene chloride to remove impurities such as oil and dust.

After uniformly mixing the microcapsules and the binder solution in a ratio of 1: 4, it was coated on the screw portions of the bolts prepared above, and the coated bolts were dried at 25 ° C. for 24 hours.

Adhesion test is performed after filling the coated bolts with nuts and curing for 24 hours at 25 ° C, then breaking loose torque until the screw starts to loosen with a torque wrench. Was measured.

When the chloroprene rubber, which is a solvent-activated adhesive resin, is not used as a component of the binder solution as in Example 1 of Table 1, only the adhesive force due to the chemical reaction of monomers and oligomers of the adhesive component is generated, which is useful in the microcapsule. Not only does the medium play a role at all, but also the adhesion decreases, and when chloroprene rubber is blended as in Example 2, physical adhesion of solvent activation by mixing solvent and chloroprene rubber in the microcapsule and anaerobic adhesion of the adhesive component Adhesion was further improved by chemical reaction adhesion of monomers, oligomers, and initiators simultaneously.

Comparative Examples 1 to 10

Microcapsules were prepared in the same manner as in Examples 1 and 2, but the CHP / DMPT combination was used as the initiator, or none at all, or either of CHP or DMPT was used to make the microcapsules.

A binder was prepared in the same manner as in Examples 1 and 2, and the same method was used to mix the microcapsules and the binder solution, to coat the required portions of the bolts, to dry and to cure the nuts, and to cure the bolts to be bonded. The pretreatment of the / nut specimen and the adhesion test were also performed in the same manner.

As a result, when the amount of chloroprene rubber in Table 1 of Comparative Examples 1 to 2 was small or large, the adhesive strength was decreased. The weak adhesion even though the solvent-activated chloroprene rubber is included was explained because the physical bonding force without the chemical reaction is all of the adhesion, while Comparative Examples 9 to 10 use only one of CHP or DMPT as an initiator in the microcapsules. In some cases, during the coating-drying process, the loss of the initiator having the opposite function in the binder solution was caused by evaporation, etc., and the adhesion was weak and jagged because the initiation reaction by the entire redox-reduction was incomplete.

Claims (2)

In order to make a microcapsule containing a monomer of an adhesive component, an organic initiator of an oxidizing agent and a reducing agent, an organic solvent, and to use them as an adhesive, a solvent-activated resin, a monomer / oligomer of another adhesive component, a coating enhancer, a coupling agent, In preparing a binder solution composed of a non-tackifier and an organic solvent, When preparing the binder solution, chloroprene rubber is used at a concentration of 0.5 to 8% by weight with respect to the binder mixed solvent as a solvent activation resin, and 15 to 25% by weight of polyester acrylate is used as the monomer / oligomer of the adhesive component. Method for producing a microcapsule adhesive, characterized in that the urethane acrylate is used at a concentration of 10 to 25% by weight, and the carboxyl-modified vinyl chloride-vinyl acetate copolymer is used as a coating enhancer at a concentration of 5 to 13% by weight based on the binder solution. . The method of claim 1, wherein N, N'-dimethyl-p-toluidine and cumene hydroperoxide are used as the organic initiator.