JPH07228847A - Adhesive agent and method for adhering - Google Patents

Abstract

PURPOSE:To provide an adhesive agent capable of preventing the slippage between the relative positions of adherends, the slippage having being generated in cases using conventional adhesives, and capable of simplifying a jig used for holding and pressure-adhering the adherends, and to produce a method for adhering. CONSTITUTION:An adhesive (an adhesive having an electrically viscous effect) comprises a liquid adhesive base material having a relative resistance of at least >=10<4>OMEGAcm and hydrophilic particles having an average particle diameter of >=1mum in an amount of >=3wt.% based on the liquid adhesive base material, and is thickened by the application of an electric field. A method for adhering comprises applying an electric field of >=2kV/mm to an adhesive having the electric viscous effect between adherends. A method for adhering comprises applying an electric voltage to an adhesive (a conventional adhesive or an adhesive having an electrical viscous effect) to accelerate the adhesion with the generated joule heat in order to adhere conductive adherends having surfaces different in thermal expansion coefficients to each other, or the like method.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel adhesive which exhibits an increase in viscosity or solidifies upon application of an electric field. The present invention also relates to a novel bonding method using this new adhesive or a conventional adhesive.

[0002]

Conventionally used adhesives are, for example, starch, sodium alginate, gum arabic, casein, glue, gelatin and other natural products, or polyvinyl alcohol, vinyl acetate-maleic acid copolymer and the like. Water-soluble adhesive in which molecules are dissolved in water, emulsion adhesive in which thermoplastic resin such as vinyl acetate is dispersed and polymerized in water or forcibly emulsified and dispersed, polyvinyl acetate, nitrocellulose, chloroprene rubber, nitrile rubber, polyvinyl butyral , Polyvinyl chloride, polyvinylidene chloride, polyethyl methacrylate, polyethyl acrylate, and other thermoplastic resins are dissolved in an organic solvent such as ethanol, toluene, ethyl acetate, and acetone to form a thermoplastic resin adhesive,
Thermosetting adhesive containing a compound having a highly reactive group such as epoxy group, polyisocyanate group and cyanoacrylate in the molecular structure, ethyl cellulose, polyvinyl acetate, ethylene-vinyl acetate copolymer, polyisobutylene, alkyd resin , A coumarone indene resin, a hot-melt type adhesive agent using a relatively low melting point thermoplastic resin such as polystyrene, and the like.

When the adherends are bonded using these conventional adhesives, it is necessary to hold the adherends so that the relative positions of the adherends do not shift until the adhesive is cured. there were. If the adherends have a relatively simple shape or the allowable range of positional deviation between the adherends is large, the problem of positional deviation can be solved by holding the adherends with a jig having a relatively simple structure. Solvable. However, on the contrary, when joining adherends having a complicated shape or when positional accuracy is required, it is difficult to perform pressure contact and design of a jig for holding the adherends. For example, a jig having a structure in which a screw is tightened for pressure contact has a drawback in that the relative positions of adherends are likely to shift during screw tightening.

Further, as a problem of the conventional adhesive bonding, there is a residual stress or a positional deviation generated when bonding different kinds of adherends having different thermal expansion coefficients. Generally, in order to cure the adhesive, a method of heating the adherend is used in order to shorten the processing time of the process or to completely cure the adhesive.
However, when different types of adherends having different thermal expansion coefficients are heated, the relative positions between the adherends are displaced, particularly at the ends of the adherends. Even if the positional deviation that occurs at this time does not pose a problem, when the temperature is returned to room temperature after the completion of curing, a stress corresponding to the deviation remains in the joint.

This stress becomes particularly large when an adhesive having a high Young's modulus, such as a thermosetting adhesive, is used in a thin adhesive layer having a thickness of 50 μm or less, and tends to cause peeling of the adhesive. In order to avoid this problem, it is possible to cure the adhesive at room temperature, but in this case, it takes a very long time to cure, or if the curing is incomplete, moisture may come into direct contact with the adhesive. In that case, it becomes impossible to form a reliable joint.

In the conventional adhesives or bonding methods, regardless of the adherend, the above-mentioned problems are large and small, but precise alignment such as a head for printing by the ink jet method is required. In the case of joining, the above problems become particularly serious. For example, in recent years, especially in the on-demand type ink jet method, a so-called multi-channel head having a plurality of ejection ports is used in most cases. In a multi-channel ink jet type head, a very minute positional deviation becomes a problem. In particular, a minute positional deviation between the partition walls between the channels and the actuator or a positional deviation between the actuator and the nozzle causes variations in the droplet velocity between the channels, variations in the droplet volume, or variations in the ejection direction, and these variations occur. If so, the print quality deteriorates.

Further, in the head for printing by the ink jet method, the joint portion is often in direct contact with the ink. In particular, the partition wall between the channels is a wall for separating the ink flow path for each channel, and the joint portion inevitably comes into contact with the ink. In addition, since the ink also passes through the inside of the nozzles at the adhesive portion of the nozzle plate, the joint portion inevitably comes into contact with the ink. When the joint portion directly contacts the ink as described above, it is required that the adhesive used for the joint has particularly high durability. Generally, an adhesive with high liquid resistance is an adhesive with a high curing temperature, and if the adhesive is cured at a high curing temperature, the displacement and residual stress between the members to be joined will occur, as described above, and the print quality And deterioration of durability will occur. Therefore, the ink jet head having multi-channels causes a serious problem especially when the number of channels is large and the entire head is long.

In a multi-channel ink jet recording head, as means for solving these problems,
Japanese Patent Application Laid-Open No. 55-17576 describes a method of soldering a partition wall or a nozzle plate. However, solder has a drawback in that not only sufficient adhesive strength cannot be obtained, but also the durability against ink is lacking, so that peeling of an adhesive portion and clogging of a nozzle are likely to occur. Japanese Patent Publication No. 63-54547 proposes a method of integrating head constituent members by using a radiation-curable adhesive. Currently available practical radiation-curable adhesives are cured with ultraviolet rays, but the head components that are normally used are opaque to ultraviolet rays, and in this case, even if the joints are exposed to ultraviolet rays, Since ultraviolet rays do not reach to, it cannot be cured. Therefore, there is a drawback that the head constituent members are significantly restricted.

Further, Japanese Patent Laid-Open No. 59-103764 proposes a method of bonding by diffusion bonding.
Although strong bonding can be obtained by diffusion bonding, the processing temperature is extremely high, so there are restrictions when using a material with weak heat resistance such as plastic or a material with a different linear expansion coefficient for part of the head. There is a drawback that the conditions become strict. Japanese Unexamined Patent Publication No. 61-78653 proposes a method of temporarily adhering with an adhesive having a fast curing speed and then joining head constituent members with an adhesive having a high adhesive strength. In this case, a holding jig for joining may be unnecessary in joining after temporary joining, but the above-mentioned problems that occur when joining members having different thermal expansion coefficients cannot be solved yet. . Japanese Patent Publication No. 58-5753 proposes a head in which members are precisely joined by electrostatic joining without using an adhesive or solder. With this joining method, the dimensional accuracy is easy to maintain, but there are problems that a large joining force cannot be expected and the electrostatic force deteriorates.

[0010]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems and can prevent the displacement of the relative position of the adherend that occurs when a conventional adhesive is used, or An object of the present invention is to provide an adhesive and a bonding method capable of simplifying a jig for holding and pressing a body.

[0011]

According to the present invention, at least 3 wt% of a liquid adhesive base having a specific resistance of 10 ⁴ Ωcm or more and hydrophilic particles having an average particle size of 1 μm or more are added to the liquid adhesive base. % Or more, and an adhesive (hereinafter abbreviated as an adhesive having an electrorheological effect) characterized by thickening or solidifying by applying an electric field is provided. The particles have a dissociative functional group of 1 meq / g or more, and the hydrophilic particles are
Particles having a structure composed of at least two layers of a high molecular weight polymer layer having a specific gravity of 1.1 or less constituting the core portion and a compound layer having a hydrophilic group constituting the surface portion thereof,
The liquid adhesive base comprises a reaction-curable base,
Furthermore, in the hydrophilic particles, having a functional group that reacts with the liquid adhesive base, the hydrophilic particles,
There is provided the above-mentioned adhesive characterized in that it is impregnated with a compound that reacts with the liquid adhesive base and / or a compound that accelerates the curing reaction of the adhesive base.

Further, according to the present invention, the adhesive is present between adherends having a substantially conductive surface, and the adhesive is applied with an electric field of 2 kV / mm or more. There is provided an adhesion method characterized by pressing an adherend and curing the adhesive, and in particular, the above-mentioned adhesion method characterized in that the applied electric field is an alternating electric field.

Further, according to the present invention, an adhesive is present between adherends having substantially conductive surfaces, an electric field is applied to the adhesive, and the adhesive is heated by a current flowing through the adhesive. There is provided a bonding method characterized by accelerating the curing of the adhesive, and in particular, the adherend is made of different materials having different thermal expansion coefficients, and substantially the whole adherend is heated. Without heating, only the adhesive present between the adherends to accelerate curing, and at this time, the adhesive is characterized by the adhesive having the electrorheological effect, respectively. Provided.

Further, according to the present invention, an electric field is applied to an adhesive existing between adherends having substantially conductive surfaces,
Provided is a bonding method characterized by detecting a flowing current or by detecting a capacitance between adherends and feeding back the detected current value or capacitance to perform alignment between the adherends. In particular, the adhesive method is provided, wherein the adhesive is an adhesive having an electrorheological effect.

Further, according to the present invention, a liquid which is thickened or solidified by applying an electric field to the conductive portion of the adherend, at least a portion of the surface of which is substantially conductive, will be described below. , Abbreviated as electrorheological liquid) and applying an electric field to the liquid so that the relative position of the adherend does not shift, and then an adhesive agent is applied to the portion of the adherend not coated with the liquid. Is provided, or an adhesive applied in advance is cured to bond the adherends.

The present invention will be described in more detail below. When an electric field is externally applied to a liquid in which specific solid particles are dispersed or suspended in a specific electrically insulating liquid, a phenomenon in which the viscosity of the liquid significantly increases or solidifies is observed. Is known as the Winslow effect. A fluid exhibiting such characteristics is proposed to be applied to a clutch, a damper, a hydraulic control device, a vibrating element, etc., and by adding a colorant, it is also applied as an ink for a printer for forming an image. Proposed.

As a fluid (electrorheological fluid) showing such a phenomenon, US Pat. No. 2,417,850 discloses hydrophilic powders such as starch, wheat flour, gypsum, carbon and limestone in mineral oil, olive oil and trans oil. A fluid suspended in an insulating oil is disclosed. In addition, Japanese Patent Publication No. 52-30273
Japanese Patent Publication discloses an electrorheological fluid using an ion exchange resin as particles. However, Winslo
Adhesives with a w-effect are not yet known.

Conventionally, a method of dispersing particles of aluminum powder, silver powder, talc, silica, calcium carbonate, titanium oxide, zinc oxide, asbestos, carbon black, etc. in an adhesive and using it is known. However, the purpose of adding conventional particles is to reduce the coefficient of thermal expansion, increase Young's modulus, increase the viscosity to facilitate the application of an adhesive, adjust the mixing ratio with a curing agent, and adjust the adherend appropriately. It is used as a spacer for keeping the distance, and the diameter of the added particles is 0.2 μm or less in diameter, or even if particles of 1 μm or more are rarely used, the purpose is to be a spacer. The added amount was less than 3 wt%. When the diameter of the added particles is 0.2 μm or less, the electrorheological effect is not exhibited even if particles having relatively high hydrophilicity such as silica are used.

The inventors of the present invention have used a liquid adhesive base having a specific resistance of 10 ⁴ Ωcm or more and 3 wt% with respect to the adhesive base.
% Or more, by suspending hydrophilic particles having an average particle size of 1 μm or more, Winslow effect, that is, an adhesive having an effect of thickening or solidifying by applying an electric field, in other words, an electrorheological effect Can be obtained by using this adhesive, or by Winslow
By using a liquid having an effect, that is, an electrorheological liquid, it is possible to perform precise assembly at the time of assembling an ink jet recording head or the like having a plurality of ejection ports that are configured by channel intervals or nozzle plates and require precise joining. They have found that they can be joined and bonded, and have completed the present invention.

The adhesive base used in the present invention is a liquid and has a specific resistance of 10 ⁴ Ωcm or more. When the specific resistance of the adhesive base is less than 10 ⁴ Ωcm, the desired electroviscosity cannot be obtained. To obtain a large electrorheological effect,
The specific resistance of the adhesive base must be 10 ⁴ Ωcm or more.

As the liquid adhesive base material having a specific electric resistance of 10 ⁴ Ωcm or more, conventionally known liquid adhesives other than water-based adhesives and hot melt adhesives can be used. As a more specific example of the liquid adhesive base that can be used in the present invention, an adhesive containing a bisphenol compound having an epoxy equivalent of 170 to 300 as a main component, metaxylene diamine, 1,3-bisaminomethylcyclohexane. An adhesive containing a tetrafunctional glycidyl amine compound as a main component, tolylene diisocyanate, hexamethylene diisocyanate,
Isophorone diisocyanate, xylylene diisocyanate, Coronate L, Coronate HL, Coronate 20
30, adhesive containing polyisocyanate compound such as Millionate MR as a main component, methyl-2-cyanoacrylate, ethyl-2-cyanoacrylate, n-propyl-
Examples include cyanoacrylate adhesives such as 2-cyanoacrylate, i-propyl-2-cyanoacrylate, n-butyl-2-cyanoacrylate, solvent-type adhesives in which vinyl acetate, vinyl chloride, chloroprene, etc. are dissolved in a solvent. be able to.

The liquid adhesive base is preferably an adhesive of a type in which curing of the adhesive proceeds by a molecular reaction, and particularly preferable is a solvent-free reaction such as an epoxy type, polyisocyanate type or cyanoacrylate type. It is a curable adhesive. When an electric field is applied to the adhesive having an electrorheological effect of the present invention to solidify the adhesive in a state where there is substantially no fluidity of the adhesive, the hydrophilic particles form a crosslinked structure in the uncured adhesive layer. However, in the solvent evaporation curing type adhesive, the solvent evaporates while the particles are crosslinked, and voids are generated in the adhesive layer, so that the adhesive strength tends to decrease.
When a solventless reaction-curing adhesive is used as a base material, such a problem of void generation does not occur.

In the present invention, examples of the hydrophilic particles suspended in the base include silica, cellulose powder, starch,
-COOM in the _{molecule, -SO 3 M, -OM, -SM} , -
_{N (R 1, R 2,} R 3), - P (R 1, R 2, R 3) ( wherein, M is hydrogen, sodium, potassium, alkali metals such as lithium, ammonium, a phosphonium compound, R ₁ , R ₂ and R ₃ are each a hydrogen or an alkyl group which may have a substituent) and the like, which is a synthetic polymer particle having a functional group. These particles are prepared or synthesized by a conventionally known method.

In order to achieve the object of the present invention, the diameter of the particles to be added is 1 μm or more, preferably 2 to 20 μm.

Among these hydrophilic particles, a particularly large electrorheological effect is obtained when an electric field is applied, when the hydrophilic particles are particles having a dissociative functional group of 0.1 meq / g or more. . A typical example of this particle is an ion obtained by introducing a functional group such as sulfonic acid, carboxylic acid, primary to quaternary amine or ammonium salt into the particle obtained by copolymerizing styrene and divinylbenzene. These particles are commercially available as an exchange resin. However, in general, so-called ion exchange resins having a particle size of 0.25 to 2.0 mm are commercially available, and the use of particles of such a size gives a large electrorheological effect, Is not always preferable for maintaining the positional accuracy of.

As the particles having a dissociative functional group of 0.1 meq / g or more, in addition to the above particles, a polymer containing acrylic acid such as a copolymer of acrylic acid and N, N-methylenebisacrylamide. , Carboxymethyl cellulose, those obtained by introducing the above-mentioned dissociative functional group into cellulose such as those obtained by dyeing cellulose particles with a reactive dye,
Examples thereof include acrylamide copolymers such as copolymers of acrylamide and ethylene glycol dimethacrylate, and bulk aggregates of acid dyes, direct dyes, basic dyes and the like.

The hydrophilic particles do not necessarily have to be composed entirely of the compound having a dissociative functional group as described above, but may be composed of, for example, polyethylene, a compound obtained by copolymerizing styrene and divinylbenzene, or the like. In the vicinity of the surface of the particles, a multilayer structure having the dissociative functional group,
It is also preferable to use particles having a hydrophilic group on the surface.

The particle size of the present invention is 1 μm or more and 0.1
In order to obtain particles having a dissociative functional group of m equivalent / g or more, it is necessary to pay attention so that particles having a target particle size can be obtained by selecting emulsification conditions and dispersion conditions when polymerizing the particles. is there. Particles having a desired particle size can also be obtained by pulverizing a commercially available ion exchange resin with a mortar or a jet mill and then classifying the same.

Further, in the present invention, as the hydrophilic particles,
It is preferable that the core portion is composed of a polymer layer having a specific gravity of 1.1 or less, and the surface portion is composed of at least two layers of a compound layer having a hydrophilic group. The reason why the high molecular weight polymer having a specific gravity of 1.1 or less is used for the core part is as follows. That is, in an ordinary electrorheological fluid, a liquid having a relatively high specific gravity containing a large amount of halogen elements such as chlorine and bromine and phosphorus can be used as a medium for dispersing or suspending particles, but in an adhesive, it is possible to bond them. Since it is important to have such a function, it is difficult to raise the specific gravity of the liquid adhesive base used in the present invention to the level of a commonly used electrorheological fluid medium. Therefore, the specific gravity of the particles used in the adhesive of the present invention is required to be smaller. In particular, by using a high molecular weight polymer having a specific gravity of 1.1 or less, the specific gravity of the whole particles can be determined by the specific gravity of the liquid adhesive base. And the storage stability and dispersion stability of the adhesive having the electrorheological effect according to the present invention can be improved.

Preferred as the polymer forming the core of the particles according to the present invention are polyethylene, polypropylene, nylon 6, nylon 11, polystyrene, ABS.
It is a polymer having a specific gravity of 1.1 or less such as resin, polyvinyl butyral, natural rubber and butyl rubber.

As described above, the adhesive having an electrorheological effect of the present invention has a high print quality, excellent durability, and an inexpensive ink jet recording head, and particularly has an on-demand type multi-channel. It is preferably applied to joining at the time of making an ink jet recording head. At this time, the thickness of the adhesive layer at the joint portion of the ink jet recording head has a great influence on ejection characteristics such as droplet velocity, droplet volume, and mutual interference between channels, but it is made of only hydrophilic compounds as particles. In the case of using, the hydrophilic compound is generally easy to absorb water, and volume expansion is caused due to water absorption, and the thickness of the adhesive layer is easily changed.

In particular, when the adhesive layer is in direct contact with the ink, this problem often occurs because the ink jet recording ink usually used is a water-soluble ink. As described above, a polymer having a specific gravity of 1.1 or less is generally not hydrophilic and has a low water absorption coefficient. However, by using these particles, the storage stability of the adhesive having the electrorheological effect of the present invention is improved. Besides this problem, this problem can be solved at the same time.

The compound layer, which is the surface portion of the hydrophilic particle of the present invention, is composed of a compound having a hydrophilic group. As the hydrophilic group, -OH, -COOH, -SH, -SO 3
Examples thereof include anionic groups such as H, and cationic groups such as primary to quaternary amines.

As the compound having such a hydrophilic group, polyvinyl alcohol, polyacrylic acid, polymethacrylic acid, carboxyethyl cellulose, hydroxyethyl cellulose, alginic acid, starch, gum arabic, tannin, rosin, lignin sulfonic acid, gelatin, casein, Polyethylene oxide, maleic anhydride copolymer, polystyrene sulfonic acid, polyvinyl sulfonic acid, polyacrylamide, polyvinyl pyrrolidone,
Polymer compounds such as polyvinyl pyridine, and cationic polymer compounds having the following structures

[Chemical 1] (M is an integer of 1 to 30, and R ₁ , R ₂ , and R ₃ are alkyl groups or hydrogen atoms.)

Embedded image —CH ₂ CH ₂ NH—

[Chemical 3]

[Chemical 4] (M and n are integers of 1 to 30.)

[Chemical 5] (R ₄ is an alkyl group or a hydrogen atom.)

[Chemical 6] (R ₅ is an alkyl group or a hydrogen atom.)

[Chemical 7]

[Chemical 8]

[Chemical 9] (R ₆ and R ₇ are an alkyl group or a hydrogen atom.)

[Chemical 10] (R ₈ , R ₉ and R ₁₀ are alkyl groups or hydrogen atoms, and m is 1 to
It is an integer of 10. )

[Chemical 11] (R ₁₁ , R ₁₂ and R ₁₃ are alkyl groups or hydrogen atoms, m is 1
Is an integer of -30. )

[Chemical 12] (R ₁₄ and R ₁₅ are an alkyl group or a hydrogen atom.)

[Chemical 13] (R ₁₆ , R ₁₇ , and R ₁₈ are an alkyl group or a hydrogen atom,
m is an integer of 1 to 30. ) And the like.

Inorganic compounds such as silica gel, calcium carbonate and barium sulfate can also be used as the surface coating layer 2. It is preferable that the anionic compound contains, as its counter ion, cation such as H ₊ , Na ₊ , K ₊ , Li ₊ , and NH _{4 +} quaternary ammonium ion, which are easily dissociated. Similarly, in anionic compounds, OH ⁻ , Cl ⁻ ,
It is preferable to contain Br ⁻ , I ⁻ , F ⁻ , BF ₄ ⁻ , NO ₂ ^{− and the} like.

An electrically responsive fluid in which a material having a specific gravity of 1.2 or less is used as a core material, and particles obtained by coating the core material with a hydrophilic compound is suspended in an electrically insulating liquid is disclosed in JP-A-3-162494.
The hydrophilic particles composed of the high molecular polymer layer of the core portion and the compound layer having a hydrophilic group of the surface portion of the present invention can be produced by a method similar to that of the electrically responsive vortex. it can.

That is, as a typical method, (i) particles of the core substance are suspended in an air stream, and a solution of the coating substance is sprayed and atomized and mixed in the air stream to form a coating on the surface. A solid-liquid contact method of settling and collecting particles having a high density generated, (ii) a solid-solid contact method of transporting both the finely divided coating material and the core material in a jet stream, and colliding, ( iii)
A solid-gas contact method in which a monomer of the coating compound is introduced while stirring the core substance in a vacuumed chamber and causes plasma polymerization or photopolymerization on the surface of the core substance. Solid-
The solid contact method is particularly effective for providing a surface coating layer of a compound that is difficult to form a solution such as silica gel. In the solid-gas contact method, it is effective to increase the production efficiency by adhering or adsorbing an initiator or a catalyst for promoting the polymerization on the surface of the core material in advance.

The magnitude of the electrorheological effect to be expressed greatly varies depending on the amount of liquid having high polarity such as water contained in the particles. Therefore, when preparing the adhesive of the present invention, it is necessary to control the amount of water contained in the particles.
~ 1.5 wt%.

Although an adhesive having the electrorheological effect of the present invention can be obtained by using particles containing water, the inclusion of water tends to reduce the strength of the adhesive after curing. In the present invention, in order to prevent this and maintain a stronger adhesive strength, it is preferable to impregnate the hydrophilic particles with a compound that reacts with the adhesive base to form a chemical bond. It is particularly preferable to use a reaction-curable adhesive as the adhesive base and impregnate the curing agent or the curing agent dissolved in an organic solvent.

Specifically, when an epoxy adhesive is used as an adhesive base, aliphatic polyamines such as ethylenediamine, triethylenetetramine, diethylenetriamine, alicyclic polyamines, metaphenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, etc. The particles can be impregnated with an epoxy curing agent such as the aromatic polyamine, polybasic acid and its anhydride. On the other hand, when urea resin, phenol resin, or melamine resin is used as the adhesive base, formaldehyde can be impregnated into the particles before use.

When the polyisocyanate adhesive is used as the adhesive base, the same aliphatic polyamines, alicyclic polyamines, aromatic polyamines and polybasic acids as those used for the epoxy adhesive can be used. In addition, particles can be impregnated with polyhydric alcohols such as diethylene glycol, propylene glycol, ethylene glycol, water-added bisphenol, neopentyl glycol, dipropylene glycol, 1,3-butylene glycol, and bisphenol dioxyethyl ether. .

These curing agents have a strong polarity, and even if particles containing substantially no water are used, it is possible to obtain a sufficiently large electrorheological effect by impregnating these compounds. It is possible to reduce the current value when an electric field is applied to the adhesive, and there is an advantage that a large-capacity high-voltage power supply is not required even when bonding a relatively large area.

Further, in the present invention, as the compound which is preferably impregnated into the hydrophilic particles, not only a compound which reacts with the adhesive base material to form a chemical bond but also a compound which accelerates the reaction of the base material may be used. it can. For example, when an epoxy-based adhesive is used as the adhesive base, a curing accelerator such as hydrochloric acid, salicylic acid, boron trifluoride or stannic chloride can be used. When a polyisocyanate adhesive is used as an adhesive base, triethylamine, zinc naphthenate, sodium o-phenylphenate, potassium oleate, tetra (2-ethylhexyl) titanate, cobalt 2-ethylhexoate, lead 2 -The particles may be impregnated with a curing accelerator such as ethylhexoate and used. These curing accelerators also have strong polarities like the above-mentioned curing agents and exhibit the same effect as when impregnated with the curing agent.

The above example is an example in which the particles are impregnated with a curing agent, a reaction accelerator, etc., but it is also possible to allow the particles themselves to have a functional group which reacts with the main component of the liquid adhesive base. In the particles having a basic group or acidic group such as amine described above, when an epoxy adhesive or a polyisocyanate adhesive is used as a base, a functional group in the particles causes a chemical bond by a reaction with the base. In this case as well, the bond between the particles and the base becomes strong, so that a strong adhesive strength is obtained.

Whichever particles are used, it is necessary that the amount of hydrophilic particles is 3 wt% or more based on the adhesive base. If it is less than 3 wt%, the desired electrorheological effect cannot be obtained. If the amount of the particles is too large, the fluidity of the adhesive will be lost and the application of the adhesive will be difficult even when no electric field is applied. Therefore, the amount of the particles added is 3 to the adhesive base.
60 wt% is preferable, and the range of 7-40 wt% is more preferable.

In order to suspend the hydrophilic particles in the liquid adhesive base, conventionally known methods such as stirring with a mixer and crushing with a ball mill can be used. It is also possible to suspend the hydrophilic particles in a liquid adhesive base in advance, but when a chemical reaction occurs between the particles and the base as in the case of using a reaction-curable adhesive as the base, The particles should be suspended immediately before use. Even when a reaction-curable adhesive is used as a base, if it can be stably suspended in either the main component or the curing agent, it can be suspended in advance.

Next, a bonding method using the adhesive having the electrorheological effect obtained above will be described. In order to obtain the electrorheological effect, it is necessary that the surface of the adherend has a substantially conductive surface. Therefore, for adhesion of metals, special ceramics exhibiting conductivity, resin, glass, etc., it is possible to join the adherends without any processing. However, in order to join an insulating member such as general ceramics, resin, or glass, the surface of the adherend is made conductive by a method such as coating, vacuum deposition, sputtering, or internal addition of a conductive material to the member. There is a need.

FIG. 2 is a principle diagram showing a state in which an adherend is held while applying electroviscosity using the adhesive having the electroviscous effect of the present invention, and FIG. 2 (a) is an electric field applied. The state, FIG. 2B, shows the state when the adhesive is cured. In FIG. 2A, adherends 1 and 2 are, for example, metals such as aluminum, stainless steel, and copper, and are members having grooves formed in the depth direction of the drawing. The adhesive 4 having an electrorheological effect is applied to one of the adherends, the adherends are superposed and aligned with each other, and then the switch 6 is closed to apply an electric field from the high voltage power source 5 to the adherends 1 and 2. Applied between and. In this state, it is necessary to apply an electric field of 2 kV / mm or more between the adherends, which causes the adhesive to thicken or solidify. When the electric field strength is less than 2 kV / mm, practical electrorheological effects are hardly obtained. If the electric field strength is too strong, a sudden current leak occurs and the electrorheological effect cannot be obtained. The appropriate electric field strength is determined by the selected particles, the specific resistance of the adhesive base, the shape of the adherend, the desired electroviscosity, etc., but it is preferably used in the range of 2 to 15 kV / mm. Particularly, the range of 4 to 6 kV / mm is preferable because the electroviscosity and the current value are well balanced.

Although the mechanism of manifestation of the Winslow effect has not been completely elucidated, the phenomenon that can be observed from the outside regardless of the mechanism is that the adhesive becomes thickened or apparently solidified by the electric field. Shear stress acts so that displacement does not occur even if a force F that causes displacement is applied to the adherend. In particular, when the electric field strength is a certain value or more, even if a force of a certain value or less is applied, no positional displacement occurs at all and the solidified state is apparent.

Therefore, after the adhesive is applied to the adherends and the alignment between the adherends is performed, an electric field is applied to the extent that the adhesive is apparently solidified, so that the electric field is constant as long as the electric field is applied. Even if a force equal to or less than the value is applied to the adherends, the displacement between the adherends does not occur. As shown in FIG. 2A, by pressing the adherend or / and curing the adhesive while applying an electric field between the adherends, a jig for pressing or holding the adherend is not used at all. Alternatively, it is possible to perform adhesive bonding with high positional accuracy simply by using a simplified jig [Fig. 2
(B)].

FIG. 1 shows a case where a conventional adhesive is used. In FIG. 1A, the conventional adhesive 3 is used.
It is a figure which shows that if some force F is applied to an adherend before hardening | curing, it will displace easily and it will become like FIG.1 (b).

The voltage applied to the adhesive exhibits an electrorheological effect even with a DC voltage, but when a DC voltage is applied, minute electrophoretic migration occurs in the particles and the distribution of the particles is biased, which causes the electrorheological effect to change over time. Changes may occur. In addition, the surface of the adherend is easily damaged. In order to eliminate these drawbacks, the electric field is preferably an alternating electric field. In particular, it is preferable to use an AC electric field close to a rectangular wave, and in this case, the applied voltage is twice the electric field value described above at peak-peak.

When an electric field is applied by the above method using the adhesive having the electrorheological effect according to the present invention, a current flows through the adhesive layer. If an insulating layer is provided on the surface of the conductive layer of the adherend so that no current flows, the electrorheological effect cannot be obtained at present. The Joule heat generated by this current can heat the adhesive layer. If the current value is too small to reach the desired temperature, the adhesive may contain an organic compound containing a dissociative functional group such as a quaternary ammonium salt, a sulfonate or a carboxylate, or an alkali thiocyanate or nitrate. As described above, the electric resistance value can be adjusted by adding an inorganic salt which is relatively soluble in the adhesive. However, also in this case, the electrorheological effect cannot be obtained unless the specific electric resistance value of the entire adhesive agent is made smaller than 10 ⁴ Ωcm.

When a heating effect is applied during the curing of a general adhesive, the whole adherend is usually placed in a heating furnace,
The whole work is heated. FIG. 3 is a diagram showing a state in which the adhesive is heated and cured by a method of heating the entire work, and adherends having different thermal expansion coefficients are joined.
Since the conventional adhesive 3 adheres with the dimensions when heated as in the case of (a), if the respective adherends 1 and 2 are processed to have the same dimensions at room temperature, the relative adherence between the adherends will increase. The position shifts. Also, when the work is returned to room temperature after curing,
When the work is warped or does not warp as shown in (b), a large residual stress remains by that amount, which causes a problem that peeling of the adhesive portion is likely to occur.

Therefore, in the present invention, the above problem is solved by
An electric field is applied to the adhesive existing between adherends having a conductive surface, and the adhesive is heated by a current flowing through the adhesive,
It can be solved by a method of adhering an adherend by a method of promoting curing. That is, when the bonding method is used, only the adhesive and its vicinity are heated, so that it is possible to heat with energy efficiency, and it is particularly effective when bonding adherends having different thermal expansion coefficients. As described above, when the whole work is heated, various problems occur, but this method can solve these problems. That is, it is possible to prevent the positional deviation between the adherends, the distortion such as the warp of the work, and the residual stress.

In the method of heating this adhesive by applying an electric current, it is not always necessary to use an adhesive having an electrorheological effect, and it is clear that an adhesive having a certain degree of conductivity or more can be used. is there. However, when using an adhesive with an electrorheological effect,
Since the surface of the adhered part of the adherend needs to be electrically conductive and a certain amount of electric current must be passed in order to exert the electrorheological effect, this heating method is particularly effective for bonding with the electrorheological effect. It is more efficient to use the agent.

Conventionally, as a method of aligning the adherends, there have been a method of visually or optically detecting the position of the member and a method of mechanically using a jig. It is difficult to adjust the fine position by the method of visual observation or abutting, or the dimensional accuracy of the abutting surface is required for the adherend just to perform abutting, and the cost of the adherend becomes high. There was a problem to do. The method of detecting the position of the adherend and performing the alignment through the high-magnification optical system enables relatively accurate alignment, but such an optical system and the adherend can be moved minutely. The device having the mechanism for operating has a drawback of high cost. In addition, it is often impossible to optically detect due to the shape of the adherend.

Furthermore, in the present invention, a method of applying an electric field to an adhesive existing between adherends having a conductive portion on at least a part of the surface and detecting a flowing current, or a method of detecting an electric current between adherends These drawbacks are eliminated by performing the bonding method of detecting the capacitance and feeding back the detected current value or capacitance to align the adherends.

In FIG. 4, an electric field is applied to an adhesive existing between adherends having conductive parts, and a flowing current is detected,
It is a figure which shows the adhesion method which aligns between to-be-adhered bodies. That is, when the adherends 1 and 2 made of a conductor such as a metal are joined, a constant voltage is applied between the conductive layers, and the current value flowing through the adhesive layer is measured while the adherend is moved finely. The maximum current flows when the ridges of 1 and the ridges of the adherend 2 completely match. The fine movement of the adherend can be performed by fixing at least one of the adherends on the XY-θ stage 9 and moving the stage. This method is possible both with conventional adhesives and with the adhesives of the invention having the electrorheological effect.

In the example of FIG. 4, the adherend 1 is an insulator 8
It is fixed to the stage 7 via. The other adherend 2 is fixed on the XY-θ stage 9, and when the adhesive 4 is an adhesive having an electrorheological effect, a low electric field strength such that the adhesive 4 does not solidify is obtained. It is supplied to the adherend 1 by the power supply 5.

The current flowing at this time is detected by the ammeter 10. This current value is input to the central processing unit 11. Reference numerals 12, 13, and 14 denote pulse motors for moving the XY-θ stage 9 in the X-direction, the Y-direction, and the θ-direction, respectively. The displacement value that gives the maximum current value detected by the ammeter 10 is detected. Then, the central processing unit is programmed so that the stage is automatically sent to the displacement point where the current value becomes maximum. After the alignment is completed in this way, the adhesive is solidified and bonded. At this time, when the adhesive is an adhesive having an electrorheological effect, an electric field high enough to solidify the adhesive is supplied from the power source 5.

In FIG. 4, the current value between the adherends changes even if the distance between the adherends changes, but in order to keep the distance between the adherends constant, the adherence of the adherends themselves should be kept constant. It is preferable to previously provide a portion for controlling the film thickness of the adhesive on the attachment surface, or to add a member for controlling the film thickness in the adhesive. Examples of such a member include spherical silica and resin.

In FIG. 4, the position between the adherends can be similarly adjusted by detecting not the current value but the capacitance between the adherends and feeding back the capacitance. Also in this case, the capacity is maximum when the peaks of the adherend 1 and the peaks of the adherend 2 are completely aligned. And when detecting the capacitance, it is clear from the detection principle that the surface of the adhered part of the adherend does not necessarily have to be conductive, although each adherend needs a conductive part. .

In the above description of the bonding method using the adhesive having the electrorheological effect, the example in which the adhesive having the electrorheological effect is used for the entire bonded portion has been described. However, if it is difficult to make the entire adhesive part conductive, or if the adhesive having the electrorheological effect is not suitable for joining a specific adherend, only a part of the surface of the adherend is used. Is made electrically conductive, an electric field is applied to that portion, and an adhesive having an electrorheological effect is present in that portion, so that it is effective to prevent the adherend from being displaced.

In this case, what is required of the liquid to be present in the conductive portion is the electrorheological effect, and the liquid does not necessarily have to be an adhesive, and it is merely an electric liquid obtained by suspending hydrophilic particles in a solvent. It may be a viscous liquid. When using this electrorheological fluid for temporary fixing so that there is no misalignment and then joining, the joining method is not limited to joining with an adhesive, for example, melting joining with a solvent, fusion with heat or high frequency. Obviously, it can be applied to joining.

Specific examples of the solvent that constitutes the electrorheological liquid include aliphatic hydrocarbons such as n-hexane, n-pentane, n-heptane, isooctane, ligroin, petroleum ether and kerosene; benzene and toluene. , Xylene and other aromatic hydrocarbons; diphenylmethane, monoethyldiphenyl, triethyldiphenyl, diethyldiphenyl, diphenyl, hydrogenated triphenyl, terphenyl, 1,4-diphenylbenzene, terphenyl, phenylxylylethane, alkylnaphthalene, etc. Alkylated aromatic hydrocarbons or polycyclic aromatic hydrocarbons; ethers such as anisole, phenetole, methoxytoluene, diphenyl ether, and belarol; diethyl oxalate,
Diethyl malonate, ethyl cinnamate, ethyl abietic acid, methyl benzoate, ethyl benzoate, benzyl acetate,
Dibutyl phthalate, dioctyl phthalate, diisononyl phthalate, di-2-ethylhexyl phthalate, didecyl phthalate, ditridecyl phthalate, trioctyl trimellitate, tri-2-ethylhexyl trimellitate,
Triisodecyl trimellitate, butyl oleate, butyl stearate, dibutyl adipate, decyl adipate, butyl epoxide stearate, monoacetin, diacetin, triacetin, monobutyrin, trimethyl phosphate, triphenyl phosphate, tricresyl phosphate, etc. And the like; oleins, higher fatty acids such as stearic acid, silicone oils such as polydimethylsiloxane, polymethylphenylsiloxane, α-methylstyrene modified polydimethylsiloxane, α-olefin modified polydimethylsiloxane and the like.

These are used in consideration of the viscosity according to the application, the specific gravity of the particles to be used, etc., or a mixture of two or more compounds. Particularly, it is advantageous that the specific gravity of the particles and the specific gravity of the solvent are substantially equal to each other, and preferably they are completely equal to each other. When such a relationship is maintained, particles do not settle or float. This is because the gravity applied to the particles and the buoyancy match. In order to make the specific gravities substantially or completely coincide with each other, it is preferable to mix two or more kinds of solvents.

Further, in the present invention, it is possible to carry out the adhesive joining after temporarily fixing the electro-rheological fluid so that there is no displacement. An example of this method is shown in FIG. In FIG. 5, the glass members 15 and 16 and the glass member 1
Conductive portions 17 and 18 are provided only on the end faces of 5 and 16 by aluminum sputtering. Glass member 15
The epoxy adhesive of the commercially available conventional type adhesive 3 is applied only to the convex portions of the uneven surface of by a screen printing method [FIG.
(A)].

Next, the glass member 15 coated with the adhesive 3
And the glass member 16 are overlapped [FIG. 5 (b)]. After filling the gap between the conductive parts with the electrorheological liquid 19 and precisely aligning the members 15 and 16, an electric field is applied between the opposing conductive parts, and the alignment is performed with the electric field applied. The epoxy adhesive is hardened and the glass members 15 and 16 are bonded together so that they will not be displaced (FIG. 5C).

The effects of the present invention are summarized as follows. Since the adhesive according to the invention of claim 1 has an electro-viscous effect which has not been obtained in the past, it is possible to have a function of preventing displacement of the adherend by applying an electric field to the adhesive. In the adhesive according to the second aspect of the invention, since the hydrophilic particles contain a dissociative functional group of 0.1 equivalent / g or more, a particularly large electrorheological effect can be obtained, and the effect of preventing the positional deviation is also large. . In the adhesive according to the invention of claim 3, the hydrophilic particle has a core portion composed of a polymer layer having a specific gravity of 1.1 or less and a surface portion composed of at least two layers of a compound layer having a hydrophilic group. Since these particles have a large electro-viscous effect, the effect of preventing positional deviation is also great. In the adhesive according to the invention of claim 4, since the base material is a reaction-curing type adhesive, there is little or no solvent evaporation at the time of curing, so it is difficult to form voids in the adhesive after curing. Therefore, it becomes possible to obtain a large adhesive strength. In the adhesive according to the invention of claim 5, since the particles contained in the adhesive react with the base material to form a chemical bond, the strength of the adhesive can be improved. In the adhesive according to the invention of claim 6, the particles contained in the adhesive are impregnated with a compound for reacting with the base material to form a chemical bond and / or a compound for promoting the curing reaction of the base material. The particles have the same electrorheological effect as when the particles contain water, and also have the effect that the current value when an electric field is applied can be reduced and the bonding strength can be improved. In the bonding method according to the invention of claim 7, since an adhesive having an electrorheological effect is used and the adhesive is held and cured and / or pressure-contacted while an electric field is applied, there is no displacement between the adherends. Joining is possible. In the bonding method according to the invention of claim 8, since the electric field for obtaining the electrorheological effect is an alternating electric field, it is possible to obtain the electrorheological effect which does not change with time and prevent deterioration of the electrode portion. In the bonding method according to the invention of claim 9, heating is carried out by passing a current through the adhesive to promote the effect of the adhesive, so that heating with high energy efficiency is possible. In the bonding method according to the tenth and eleventh aspects of the present invention, since the entire adherend is not heated, even when joining materials having different thermal expansion coefficients,
It is possible to perform bonding without problems such as displacement, distortion, and residual stress applied to the adhesive portion. Claims 12 and 1
In the bonding method according to the third aspect of the invention, the current values flowing between the adherends are detected or / and the capacities between the adherends are detected while detecting the capacitance between the adherends, which is relatively inexpensive. The device can be used to easily and highly accurately align the adherends. In the adhesion method according to the fourteenth aspect of the invention, since the liquid having electroviscosity is applied only to a portion of the adherend which is required to prevent the positional deviation, the electric field is applied to prevent the positional deviation. It is possible to prevent the positional deviation when it is not conductive and to apply another joining method to other portions.

[0071]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto. First, examples of adhesives having an electrorheological effect will be described. Example 1 100 parts by weight of bisphenol A-based adhesive base resin having an epoxy equivalent of 190 30 parts by weight of crystalline cellulose powder (average particle size 5.8 μm) were mixed and stirred with a mixer, and then, with respect to 100 parts by weight of the mixture. 37 parts by weight of an aliphatic polyamine curing agent was added to obtain an adhesive that was cured at room temperature. Before the adhesive was cured (within 16 minutes after mixing with the curing agent), the following viscosity and shear force measurements were performed. 25 ℃ of this adhesive when no electric field is applied
The viscosity at was 27 poise. When a stainless steel plate was used as the electrode and a DC electric field of 4 kV / mm was applied to this adhesive, the stainless steel plate was not displaced until a shearing force of 13 gf / cm ² was applied. In addition, 1.4
In an electric field smaller than kV / mm, displacement occurred even when a small shearing force of 1 gf / cm ² or less was applied, and no electrorheological effect was observed.

[Comparative Example 1] An adhesive was prepared by mixing the crystalline cellulose with titanium oxide having an average particle size of 0.15 µm in the above formulation. The viscosity of this adhesive at 25 ° C. when no electric field was applied was as high as 1350 poise. An electric field was applied using a stainless steel plate as an electrode in the same manner as in Example 1. However, even when an electric field of 8 kV / mm was applied to this adhesive, a deviation occurred even when a small shearing force of 1 gf / cm ² or less was applied. However, no electrorheological effect was observed.

Example 2 100 parts by weight of bisphenol AF-based adhesive base resin having an epoxy equivalent of 170: 40 parts by weight of silica gel powder (average particle size: 3.9 μm) were mixed and stirred in a mixer, and then mixed with 100 parts by weight of the mixture. 42 parts by weight of the aromatic polyamine curing agent was added to obtain an adhesive that cures at room temperature. Before the adhesive was cured (within 15 minutes after mixing with the curing agent), the following viscosity and shearing force measurements were performed. 2 of this adhesive when no electric field is applied
The viscosity at 5 ° C. was 130 poise. When a nickel plate is used for the electrode and a rectangular wave AC electric field of 12 kV / mm (peak-peak) is applied to this adhesive,
No displacement of the nickel plate occurred until a shearing force of 6 gf / cm ² was applied. In addition, in an electric field smaller than 1.9 kV / mm, even when a small shearing force of 1 gf / cm ² or less was applied, a shift occurred, and no electrorheological effect was observed.

Comparative Example 2 An adhesive was prepared by mixing 6 parts by weight of silica gel powder having an average particle size of 0.05 μm in place of the silica gel powder having an average particle size of 3.9 μm in the formulation of Example 2. 25 of this adhesive when no electric field is applied
The viscosity at ℃ was as high as 620 poise. A nickel plate was used as an electrode and an electric field was applied in the same manner as in Example 2, but when a small shearing force of ³ gf / cm ² or less was applied to this adhesive, a rectangular wave AC electric field of 16 kV / mm was applied. A slippage occurred and no electrorheological effect was observed.

Comparative Example 3 An attempt was made to obtain a mixture having the following formulation by using silica gel powder having an average particle size of 0.05 μm in place of silica gel powder having an average particle size of 3.9 μm in the formulation of Example 2. . Epoxy equivalent 170 bisphenol AF adhesive base resin 100 parts by weight Silica gel powder (average particle size 0.05 μm) 40 parts by weight However, this mixture is in a solid state even when an electric field is not applied, and it is difficult to sufficiently stir it. Therefore, it was difficult to apply as an adhesive.

[Example 3] Carboxylic acid groups were added in an amount of about 4 meq /
The ion-exchange resin containing g was pulverized and then classified to obtain particles having an average particle size of 3.5 μm. These particles were mixed with an adhesive base of epoxy resin in the following formulation by stirring with a mixer. Epoxy equivalent 190 bisphenol A adhesive base resin 100 parts by weight Ion exchange resin containing carboxylic acid as hydrophilic group 30 parts by weight Aliphatic polyamine curing agent 3 to 100 parts by weight of mixture
7 parts by weight was added to obtain an adhesive that cures at room temperature. Before this adhesive cures (within 15 minutes after mixing with the curing agent)
The following viscosity and shear force measurements were made. The viscosity of this adhesive at 170C without applying an electric field is 170 po
It was ise. When a stainless steel plate was used for the electrode and a rectangular wave AC electric field of 8 kV / mm (peak-peak) was applied to this adhesive, the stainless steel plate did not shift until a shearing force of 23 gf / cm ² was applied.

Example 4 Using spherical particles having a mean particle size of 2.4 μm and containing sulfonic acid groups of about 0.8 meq / g, a mixture having the following formulation was mixed and suspended by a mixer. Epoxy equivalent 190 bisphenol A adhesive base resin 100 parts by weight Ion exchange resin containing sulfonic acid group as hydrophilic group 30 parts by weight Aliphatic polyamine curing agent 3 to 100 parts by weight of mixture
7 parts by weight was added to obtain an adhesive that cures at room temperature. Before this adhesive cures (within 15 minutes after mixing with the curing agent)
The following viscosity and shear force measurements were made. The viscosity at 25 ° C of this adhesive when no electric field is applied is 150 po.
It was ise. When a stainless steel plate was used as an electrode and a rectangular wave AC electric field of 8 kV / mm (peak-peak) was applied to this adhesive, the stainless steel plate was not displaced until a shearing force of 22 gf / cm ² was applied.

[Example 5], [Example 6], [Example 7], [Example 8] A styrene monomer-divinylbenzene is dispersed and polymerized to obtain a spherical crosslinked polymer having an average particle size of 2.4 µm. Got By treating the particles with fuming sulfuric acid and changing the treatment conditions, the introduced amount of sulfonic acid groups is 0.3, 0.8,
An adhesive having the following formulation was prepared using particles changed to 1.6 and 2.3 meq / g, and the shearing force by applying an electric field was measured in the same manner as in Example 4. Organic solvent-soluble vinyl acetate adhesive base resin 100 parts by weight Ion exchange resin containing a sulfonic acid group as a hydrophilic group 20 parts by weight The specific electric resistance value of the vinyl acetate adhesive base resin used at this time is 6.3 × 10. It was ⁵ Ωcm. The viscosity and the shearing force were measured in the same manner as in Example 2. The shearing force applied until the displacement occurred was measured by applying a rectangular wave AC electric field of 10 kV / mm. The results are shown in Table 1.

[Comparative Example 4], [Comparative Example 5], [Comparative Example 6] In Comparative Example 4, an adhesive was obtained in the same manner as in Example 5 except that the fuming sulfuric acid treatment was not performed. . Further, Comparative Example 5 is the same as Example 5 except that the amount of the sulfonic group introduced by the fuming sulfuric acid treatment is 0.05 meq / g.
An adhesive was obtained in the same manner as in. Further, Comparative Example 6 is an example of the adhesive of Example 6 in which no electric field was applied. For the adhesives of Comparative Examples 4 and 5, the viscosity when no electric field was applied and the shearing force when an electric field was applied were measured in the same manner as in Example 5, and the results are shown in Table 1.

[0080]

[Table 1]

Example 9 A two-layer structure having silica gel as a hydrophilic compound on the surface is obtained by colliding polyethylene spherical particles having an average particle size of about 4 μm and silica gel particles having a particle size of 0.1 μm or less in a jet air flow. Particles having a specific gravity of about 1.20 were obtained. Using the composite particles, a main adhesive agent having the following formulation was prepared in the same manner as in Example 1. Epoxy equivalent 190 bisphenol A adhesive base resin 100 parts by weight Composite particles 30 parts by weight 37 parts by weight of aliphatic polyamine curing agent is added to 100 parts by weight of the above-mentioned adhesive main component mixture, and the adhesive is cured at room temperature. I got an agent. Before the adhesive was cured (within 15 minutes after mixing with the curing agent), the following viscosity and shearing force measurements were performed. The viscosity of this adhesive at 25 ° C. when no electric field was applied was 38 poise. When a stainless steel plate was used as the electrode and a DC electric field of 4 kV / mm was applied to this adhesive, the stainless steel plate did not shift until a shearing force of 18 gf / cm ² was applied. In addition, 1.4kV /
In an electric field smaller than mm, displacement occurred even when a small shearing force of 1 gf / cm ² or less was applied, and no electrorheological effect was observed. Adhesive base compound mixed with particles at room temperature 3
After standing for a month, no sedimentation of particles was observed. When the adhesive obtained in Example 9 was allowed to stand at room temperature for 1 month, particles settled down, and redispersion was impossible by shaking the container. Therefore, in this system, it is preferable to mix the particles and the adhesive base immediately before use.

[Example 10], [Example 11], [Example 12], [Example 13], [Example 14], [Example 15] The particles used in Example 3 and Example 4 were prepared. After the treatment with the solution shown in Table 2 below, the product was dried for 8 hours in a vacuum dryer kept at 50 ° C. to remove water in the particles and obtain particles containing a curing reaction accelerator instead.

[0083]

[Table 2]

In the same manner as in Example 3, 30 parts by weight of the particles obtained by the above operation were mixed with 100 parts by weight of the bisphenol A-based adhesive base resin having an epoxy equivalent of 190, and further 100 parts by weight of the mixture. In the same manner as in Examples 3 and 4, 37 parts by weight of the aliphatic polyamine curing agent was mixed to obtain an adhesive.

An iron plate having a thickness of 2 mm and a width of 15 mm was treated with a chromic acid aqueous solution and a dried adhesion test piece was prepared. The non-adhesive part of the iron plate is covered with a Teflon tape having a thickness of about 100 μm so that the adhesion area becomes 1.5 cm ^2, and the adhesives of Example 3, Example 4, and Example 10 to Example 15 are applied, respectively, and After stacking the iron plates coated with the above-mentioned Teflon tape, a rectangular wave AC voltage of 10 kV / mm was applied for 30 minutes to cure the adhesive. Regarding the adhesive of each example,
Five test pieces were prepared. When a thermocouple was attached to the surface of the iron plate and the temperature was measured, it was saturated at about 80 ° C. The bond strength after curing was measured by a tensile tester under the conditions of a tensile speed of 1.0 mm / min. Table 3 shows the results of the average breaking strength of the samples of each example.

[0086]

[Table 3]

[Embodiment 16] FIG. 6 is a structural example of an ink jet recording head prepared by the bonding method according to the present invention. In the figure, 20 is a substrate, 21 is PZT, Zn
Electro-mechanical conversion element (piezoelectric material) such as O or LiNbO ₃ , 22 is a flow channel plate having grooves for ink flow channels, 2
3 is an ink chamber common to each channel, 24 is an ink supply tube, 25 is a nozzle plate, and 26 is wire bonding for connecting the piezoelectric element electrode of each channel and the common electrode of the piezoelectric element to the drive circuit.

FIG. 7 shows a cross section of the head of FIG. In order to reduce the driving voltage, the electro-mechanical conversion element 22
It is preferable to use a laminated piezoelectric element in which a plurality of electrodes 28 and an electro-mechanical conversion element (piezoelectric material) 22 are sandwiched. The piezoelectric material is grooved by, for example, a dicing saw and separated into actuators for each channel. An ink liquid chamber 23 is provided on the electro-mechanical conversion element 22.
Further, a vibration plate 30 for transmitting a displacement caused by driving the electromechanical conversion element is provided. The vibrating plate 30 is formed by electroforming, for example, on a nickel thin film having a thickness of about 10 μm, or on a polymer film such as polyimide, polyester, or Teflon by a method such as sputtering or vacuum deposition, using gold, nickel,
What formed the metal thin film of aluminum etc. is used preferably.

The flow channel plate 22 is a plate member having a groove portion 27 for forming a pressure chamber and a channel spacing wall portion 29 on one surface, for example. It is made by grooving a metal material such as stainless steel or nickel with a dicing saw.
The grooves can also be formed by injection molding of plastics, development after patterning exposure using a photocurable resin, etching by an excimer laser, or the like. When the flow path plate is made of an insulating material such as glass, plastic, silicon, ceramics, or photosensitive resin, in order to bond it by the method of the present invention, at least a part of the conductive part is plated, vacuum deposited, sputtered. It is necessary to provide it by a method such as coating.

In the figure, a channel head is shown to show the concept, but in a normal serial type head,
The number of channels required for one main scan is the number of surface elements, that is, 3
It is preferable that the number of channels is 2 to 128. The channel pitch is preferably 50 to 500 μm.

As an example of trial manufacture, a stainless steel plate having a thickness of 3 mm was used as a flow path plate, and 250 μ with a dicing saw.
A grooved groove for 64 channels was prepared. Laminate PZT as a piezoelectric element on a ceramic substrate with a thickness of 1.5 mm, and use P with a dicing saw.
Grooves were formed so that ZT was separated for each channel.

Nickel diaphragm and PZT produced by electroforming
After bonding and, the vibration plate and the flow path plate were bonded according to the bonding method of the present invention. That is, after applying the adhesive of Example 2 to the joint surface of the flow path plate by the screen printing method,
By aligning and superposing with the vibration plate, an AC electric field is applied between the vibration plate and the flow path plate so that the electric field strength is 10 kV / mm, and the heat generated by the current flowing through the adhesive layer is used. Then, heat curing for 30 minutes was performed without using a pressure welding jig. Further, by applying an electric field between the nozzle plate and the flow path plate, the nozzle plate having the nozzle holes formed by electroforming is adhered to the nozzle plate in the same manner as the bonding between the vibration plate and the flow path plate. Joined. The ink jet recording heads manufactured by these methods of the present invention show good printing characteristics and have little variation in ejection characteristics such as droplet speed between channels, and are subjected to a continuous drive test for 200 hours. No significant change was observed in the ejection characteristics before and after the test.

[Comparative Example 7] The adhesive between the vibration plate and the flow path plate bonded on the PZT was cured by placing them in a thermostat kept at 80 ° C for 30 minutes while pressing them with a jig. A head was manufactured in the same manner as in Application Example 1 except for the above. With this head, normal ejection characteristics were obtained in the channel in the center of the head, but no ink was ejected in the channels near the edges. When this head was cut and the cross section was observed, the flow path and P
It was observed that the displacement with the ZT actuator was large. It was presumed that this misalignment was caused by the difference in the coefficient of thermal expansion between PZT and stainless steel, which is the material of the flow path plate, because the entire head was heated when the head was bonded and cured. Further, the head manufactured by this method could not discharge even in the central portion after continuous driving for about 33 hours. When the head was cut and the cross section was observed, peeling occurred at the joint between the diaphragm and the flow path plate. It is presumed that this peeling is due to the shear stress due to the thermal strain remaining during the heat curing.

Example 17 An ink jet recording head was produced in the same manner as in Example 16 except for the points noted below. Instead of the diaphragm made of nickel used in Example 16, a mask having openings at positions corresponding to the joints of the flow path plate partition walls of a polyimide film having a thickness of 10 μm was overlaid, and the amount of the mask was about 1.
000 A of nickel was provided by sputtering. The PZT and this diaphragm were aligned with each other by using an optical microscope by utilizing transparency other than the sputtered portion of the film, and after the alignment, they were bonded and bonded. When performing the adhesive bonding between the vibration plate provided on the PZT and the flow path plate, this time, when the positions of the vibration plate and the flow path plate are completely aligned, the capacitance between them is maximized. I made use of that.

The ink jet recording head manufactured by the method of the present invention was tested for ejection characteristics and driving durability in the same manner as the head of Example 16, and as a result, it showed good printing characteristics, such as droplet speed. The variation in ejection characteristics among the channels was also small. In addition, no significant change was observed in the ejection characteristics before and after the 200-hour continuous drive test. As shown in this example, the method of aligning the adherends by measuring the capacitance or current value between the adherends, even if the adherend is opaque, No need for expensive alignment equipment,
Provides simple, quick, and accurate alignment.

In the sixteenth and seventeenth embodiments, the examples of the adhesive and the adhering method of the present invention are described only for the ink jet recording head having the characteristic structure. Is limited to a specific head structure and is not applicable.

[0097]

The liquid adhesive base material having a specific resistance of 10 ⁴ Ωcm or more and hydrophilic particles having an average particle diameter of 1 μm or more according to the present invention are contained in an amount of 3 wt% or more with respect to the liquid adhesive base material, and an electric field is applied. An adhesive (adhesive having an electrorheological effect) characterized by being thickened or solidified by applying an electric field of 2 kV / mm or more to the adhesive having the electrorheological effect between the adherends. The method of applying and applying a voltage to the adhesive (conventional type or an adhesive having an electrorheological effect) for the adhesion between adherends whose surfaces have different thermal expansion coefficients is Joule heat. The precision bonding adhesive and the precision bonding adhesive by the method of accelerating the adhesion or the bonding method using the positioning means by the adhesive having the electrorheological effect, etc. are generated in the conventional bonding process. Relative to adherend It is possible to prevent the displacement of the position, or to simplify the jig for holding and pressing the adherend.

[Brief description of drawings]

FIG. 1 is a state diagram when a conventional adhesive is used for adhesion.
It is a figure which shows that if some force is applied to an adherend before hardening like (a), it will be easily displaced and it will be in the state of (b).

FIG. 2 is a state diagram when bonding is performed using the adhesive having an electrorheological effect of the present invention. It is a figure which shows the state (b) which does not generate | occur | produce a position shift even if an external force is applied to the state (a) which hold | maintains a to-be-adhered body while giving electroviscosity.

FIG. 3 is a state diagram when an adhesive is heat-cured by a method of heating the entire work, and adherends having different thermal expansion coefficients are joined. (A) is a state in which the relative positions of the adherends are displaced,
FIG. 6B is a diagram showing a state where the work is warped when the work is returned to room temperature after curing.

FIG. 4 is a schematic diagram showing a bonding method in which an electric field is applied to an adhesive existing between adherends having a conductive portion, a flowing current is detected, and alignment between the adherends is performed.

FIG. 5 is a diagram showing an example of a bonding method in which the electrorheological liquid of the present invention is temporarily fixed so that there is no displacement and then adhesive bonding is performed.

FIG. 6 is a structural example of an ink jet recording head formed by the bonding method of the present invention.

7 is a sectional view of the head shown in FIG.

[Explanation of symbols]

 1 Adherent 2 Adherent 3 Conventional Adhesive 4 Adhesive with Electrorheological Effect 5 High Voltage Power Supply 6 Switch 7 Stage 8 Insulator 9 XY- [Theta] Stage 10 Ammeter 11 Central Processing Unit 12 Pulse Motor 13 Pulse motor 14 Pulse motor 15 Glass member 16 Glass member 17 Conductive part 18 Conductive part 19 Electrorheological liquid 20 Substrate 21 Electro-mechanical conversion element (piezoelectric material) 22 Flow path plate 23 Ink chamber 24 Ink supply pipe 25 Nozzle plate 26 Wire bonding 27 Groove 28 Electrode 29 Channel Interval Wall 30 Vibration Plate

Claims (14)

[Claims] 1. A liquid adhesive base having a specific resistance of 10 ⁴ Ωcm or more and hydrophilic particles having an average particle size of 1 μm or more are contained in an amount of 3 wt% or more with respect to the liquid adhesive base, and an electric field is applied. An adhesive characterized by being thickened or solidified by. 2. The adhesive according to claim 1, wherein the hydrophilic particles are particles having a dissociative functional group of 0.1 meq / g or more. 3. A structure in which the hydrophilic particles are composed of at least two layers, that is, a high molecular weight polymer layer having a specific gravity of 1.1 or less constituting a core portion thereof and a compound layer having a hydrophilic group constituting a surface portion thereof. The adhesive according to claim 1, which is a particle. 4. The adhesive according to claim 1, wherein the liquid adhesive base is a reaction-curable base. 5. The adhesive according to claim 1, wherein the hydrophilic particles have a functional group that reacts with a liquid adhesive base. 6. The hydrophilic particle is impregnated with a compound that reacts with the liquid adhesive base or / and a compound that accelerates a curing reaction of the adhesive base. The adhesive according to 1. 7. An adhesive that thickens or solidifies by applying an electric field is present between adherends having a substantially conductive surface, and an electric field of 2 kV / mm or more is applied to the adhesive. An adhesive method, wherein an adherend is pressed in the state as it is to cure the adhesive. 8. The bonding method according to claim 7, wherein the applied electric field is an alternating electric field. 9. An adhesive is present between adherends having substantially conductive surfaces, an electric field is applied to the adhesive, and the adhesive is heated by an electric current flowing through the adhesive to bond the adhesive. An adhesion method characterized by accelerating the curing of an agent. 10. The adherend is made of different materials having different coefficients of thermal expansion, and only the adhesive existing between the adherends is heated without substantially heating the whole adherend. The bonding method according to claim 9, wherein: 11. The bonding method according to claim 9, wherein the adhesive is an adhesive that thickens or solidifies by applying an electric field. 12. An electric field is applied to an adhesive existing between adherends having substantially conductive surfaces, and a flowing current is detected or a capacitance between the adherends is detected to detect the electric current. A method of bonding, characterized in that the current values or electrostatic capacitances are fed back to align the adherends. 13. The bonding method according to claim 12, wherein the adhesive is an adhesive that thickens or solidifies by applying an electric field. 14. A liquid, which is thickened or solidified by applying an electric field, is applied to the conductive part of an adherend, at least a part of the surface of which is substantially conductive, and the electric field is applied to the liquid. To prevent the relative position of the adherend from being displaced, and then apply an adhesive to a portion of the adherend that is not coated with the liquid, or cure the previously applied adhesive by A bonding method, which comprises bonding adherends.