JP5461134B2 - Bonding agent for inorganic material and bonded body of inorganic material - Google Patents

Description

  The present invention relates to an inorganic material bonding agent composed of a paste containing metal colloidal particles, an inorganic material bonded body obtained by bonding an inorganic material using the bonding agent, and a method for manufacturing the same.

  2. Description of the Related Art Conventionally, as a method for joining inorganic materials made of metal or the like, welding is known in which metals are joined by flowing current through a welding portion and heating through a welding rod. However, the joining method by welding requires heating at a high temperature in order to melt the metal, has low workability and productivity, and is difficult to join with a fine and complicated material or a material with a large contact area.

  As a bonding method for solving such a problem, Japanese Patent No. 3772957 (Patent Document 1) discloses two layers made of ultrafine metal particles having a particle diameter of 1 to 100 nm and coated with an organic substance. Disclosed is a method in which a metal is bonded by forming a fusion layer by placing it between layers of the metal body and heating, pressurizing or energizing. This document describes an organic activity including an organic metal compound or a functional group having a chemical adsorption property to a metal as an organic substance. Further, it is described that the metal ultrafine particles are in the form of a paste dispersed and arranged in a solvent at a high concentration and can be prepared by thermally decomposing a fatty acid metal salt such as a stearic acid metal salt at about 200 to 600 ° C. Has been. Furthermore, since the ultrafine metal particles are completely covered with fatty acids, it is described that the problem of oxidation at room temperature does not occur completely.

  However, since the paste-like metal ultrafine particles used in this joining method use a single fatty acid metal salt, the protective action against the metal fine particles is small. Accordingly, the storage stability of the paste at room temperature is low, and the particle size and dispersion uniformity of the metal fine particles are likely to decrease. Furthermore, since the surface of the metal fine particles is completely covered with an organic substance, the sintering force between the metal fine particles is low, and when fired at a low temperature and a low pressure, the bonding force between the layers of the metal bodies is reduced.

Japanese Patent No. 3772957 (claims, paragraphs [0010], [0011], [0014])

  Accordingly, an object of the present invention is to use a bonding agent for inorganic materials, which has high dispersibility and storage stability at room temperature and can strongly bond inorganic materials such as metals even when fired at low temperature and low pressure. An object of the present invention is to provide an inorganic material joined body obtained by joining inorganic materials and a method for producing the same.

  As a result of intensive studies to achieve the above-mentioned problems, the inventors of the present invention have disclosed a protective colloid (or dispersant) for coating or protecting (or dispersing) metal nanoparticles, an organic compound having a carboxyl group, and a polymer dispersant. It was found that the dispersibility and storage stability at room temperature are high, and that inorganic materials such as metals can be strongly bonded even when fired at low temperature and low pressure.

That is, the inorganic material bonding agent of the present invention is an inorganic material bonding agent composed of metal colloid particles and a paste containing a dispersion medium of the metal colloid particles, wherein the metal colloid particles are metal nanoparticles ( A) and a protective colloid (B) that coats or disperses the metal nanoparticles (A), and the protective colloid (B) is an organic compound (B1) having a carboxyl group, and a polymer dispersant. (B2). The metal constituting the metal nanoparticles (A) is a metal containing at least a noble metal, and the organic compound (B1) is at least one selected from C _1-16 aliphatic carboxylic acids and aliphatic hydroxycarboxylic acids ( In particular, it is C _1-6 aliphatic carboxylic acid), and the polymer dispersant (B2) may have a free carboxyl group. The ratio of the protective colloid (B) is about 1.0 to 60 parts by mass with respect to 100 parts by mass of the metal nanoparticles (A), and the ratio of the organic compound (B1) and the polymer dispersant (B2). The former / the latter (mass ratio) = about 86/14 to 4/96.

  The present invention also includes an inorganic material joining method in which the inorganic material bonding agent is interposed between the inorganic material (C1) and the inorganic material (C2), and the inorganic material bonding agent is sintered. In this method, a noble metal (for example, gold, silver, palladium, etc.), copper or nickel may be present on at least one joint surface of the inorganic material (C1) and the inorganic material (C2).

  Further, the present invention includes an inorganic material joined body obtained by the above method.

  In the present invention, since a specific protective colloid is used as a protective colloid for coating or dispersing metal nanoparticles, the dispersibility and storage stability at room temperature are high, and even when fired at a low temperature and low pressure, a metal such as a metal Inorganic materials can be joined.

[Bonding agent for inorganic materials]
The bonding agent for an inorganic material of the present invention is composed of a metal colloid particle and a paste containing a dispersion medium of the metal colloid particle.

(Metal colloidal particles)
The metal colloid particles of the present invention are metal colloid particles composed of metal nanoparticles (A) and a protective colloid (B) that coats or disperses the metal nanoparticles (A), the protective colloid (B). Is composed of a combination of specific compounds.

(A) Metal nanoparticle The metal (metal atom) constituting the metal nanoparticle (A) is, for example, a transition metal (for example, a periodic table group 4A metal such as titanium or zirconium; a periodic table such as vanadium or niobium). Periodic Table Group 6A metals such as molybdenum and tungsten; Group 7A Metals such as manganese; Periodic Table Group 8 such as iron, nickel, cobalt, ruthenium, rhodium, palladium, rhenium, iridium and platinum Metal; periodic table group 1B metals such as copper, silver, gold), periodic table group 2B metals (for example, zinc, cadmium, etc.), periodic table group 3B metals (for example, aluminum, gallium, indium, etc.), Examples include Periodic Table Group 4B metals (eg, germanium, tin, lead, etc.), Periodic Table Group 5B metals (eg, antimony, bismuth, etc.), and the like. It is done. Metals are periodic group 8 metal (iron, nickel, rhodium, palladium, platinum, etc.), periodic table group 1B metal (copper, silver, gold, etc.), periodic table group 3B metal (aluminum, etc.) and periodic table. It may be a Group 4B metal (such as tin). In many cases, the metal (metal atom) is a metal having a high coordination property to the protective colloid, for example, a Group 8 metal of the periodic table, a Group 1B metal of the periodic table, or the like.

  The metal nanoparticles (A) may be the metal simple substance, the metal alloy, metal oxide, metal hydroxide, metal sulfide, metal carbide, metal nitride, metal boride and the like. These metal nanoparticles (A) can be used alone or in combination of two or more. In many cases, the metal nanoparticles (A) are usually single metal particles or metal alloy particles. Among them, the metal constituting the metal nanoparticles (A) is a metal (metal simple substance and metal alloy) including at least a noble metal such as silver (especially Group 1B metal of the periodic table), particularly a noble metal simple substance (for example, silver simple substance). Is preferred.

  The metal nanoparticles (A) are nanometer size. For example, the average particle diameter (average primary particle diameter) of the metal nanoparticles (A) in the metal colloid particles of the present invention is 1 to 100 nm, preferably 1.5 to 80 nm, more preferably 2 to 70 nm, and particularly 3 to 50 nm. It may be about 1 to 40 nm (for example, 2 to 30 nm).

  Further, the metal colloid particles of the present invention may contain almost no coarse particles. Therefore, the maximum primary particle diameter of the metal nanoparticles (A) is, for example, 200 nm or less, preferably 150 nm or less, and more preferably 100 nm or less. Furthermore, in the metal nanoparticles (A) (or metal colloid particles), the proportion of particles having a primary particle diameter of 100 nm or more is, for example, 10% by mass or less (for example, 0 to 0%) based on the mass of the metal (or metal component). 8 mass%), preferably 5 mass% or less (for example, 0.01 to 3 mass%), more preferably 1 mass% or less (for example, about 0.02 to 0.5 mass%). .

(B) Protective colloid The protective colloid (B) is composed of an organic compound (B1) having a carboxyl group and a polymer dispersant (B2).

(B1) Organic compound having a carboxyl group The organic compound (B1) has a carboxyl group. The number of such carboxyl groups is not particularly limited as long as it is 1 or more per molecule of the organic compound (B1), and is, for example, 1 to 10, preferably 1 to 5, and more preferably about 1 to 3. Also good.

  In the organic compound (B1), some or all of the carboxyl groups may form a salt (a salt with an amine, a metal salt, or the like). In particular, in the present invention, an organic compound in which a carboxyl group (particularly, all carboxyl groups) does not form a salt [particularly, a salt with a basic compound (a salt with an amine or an amine salt)] The organic compound having a carboxyl group can be preferably used.

Moreover, as long as the organic compound (B1) has a carboxyl group, the organic compound (B1) may have a functional group other than the carboxyl group (or a coordinating group for the metal compound or the metal nanoparticle). The functional group (or coordinating group) other than the carboxyl group is selected from, for example, a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom, etc.), nitrogen atom, oxygen atom, and sulfur atom. A group having at least one heteroatom {or a functional group such as a group having a nitrogen atom [amino group, substituted amino group (dialkylamino group etc.), imino group (—NH—), nitrogen ring group (pyridyl group) 5-8 membered nitrogen ring group, carbazole group, morpholinyl group, etc.), amide group (—CON <), cyano group, nitro group etc.), group having oxygen atom [hydroxyl group, alkoxy group (for example, methoxy group, etc.) , An ethoxy group, a propoxy group, a butoxy group and other C _1-6 alkoxy groups), a formyl group, a carbonyl group (—CO—), an ester group (—COO—), oxygen A cyclic group (such as a 5- to 8-membered oxygen ring group such as a tetrahydropyranyl group)], a group having a sulfur atom [for example, a thio group, a thiol group, a thiocarbonyl group (—SO—), an alkylthio group (a methylthio group, C _1-4 alkylthio group such as ethylthio group, etc.), sulfo group, sulfamoyl group, sulfinyl group (—SO ₂ —) etc.] and the like}. These functional groups may be contained in the organic compound (B1) alone or in combination of two or more.

  The organic compound (B1) is a compound that does not have a basic group (in particular, an amino group, a substituted amino group, an imino group, or an ammonium base) that can form a salt with a carboxyl group among these functional groups. Is preferred.

  Representative organic compounds (B1) include carboxylic acids. Examples of such carboxylic acid include monocarboxylic acid, polycarboxylic acid, and hydroxycarboxylic acid (or oxycarboxylic acid).

Examples of monocarboxylic acids include aliphatic monocarboxylic acids [saturated aliphatic monocarboxylic acids (eg, formic acid, acetic acid, propionic acid, butyric acid, caprylic acid, caproic acid, hexanoic acid, capric acid, lauric acid, myristic acid, C _1-34 aliphatic monocarboxylic acid such as stearic acid, cyclohexanecarboxylic acid, dehydrocholic acid, colanic acid, preferably _C1-30 aliphatic monocarboxylic acid), unsaturated aliphatic monocarboxylic acid (for example, olein) _C4-34 unsaturated aliphatic carboxylic acid such as acid, erucic acid, linoleic acid, and abietic acid, preferably _C10-30 unsaturated aliphatic carboxylic acid)], aromatic monocarboxylic acid (benzoic acid, naphthoic acid, etc.) C _7-12 aromatic monocarboxylic acid, etc.).

Examples of polycarboxylic acids include aliphatic polycarboxylic acids [for example, aliphatic saturated polycarboxylic acids (for example, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, cyclohexanedicarboxylic acid, etc. C _2-14 aliphatic saturated polycarboxylic acid, preferably C _2-10 aliphatic saturated polycarboxylic acid, etc., aliphatic unsaturated polycarboxylic acid (eg maleic acid, fumaric acid, itaconic acid, sorbic acid, tetrahydro C _4-14 aliphatic unsaturated polycarboxylic acid such as phthalic acid, preferably C _4-10 aliphatic unsaturated polycarboxylic acid etc.], aromatic polycarboxylic acid (eg phthalic acid, trimellitic acid etc.) C _8-12 aromatic polycarboxylic acid and the like).

Hydroxycarboxylic acids include hydroxymonocarboxylic acids [aliphatic hydroxymonocarboxylic acids (eg, glycolic acid, lactic acid, oxybutyric acid, glyceric acid, 6-hydroxyhexanoic acid, cholic acid, deoxycholic acid, chenodeoxycholic acid, 12-oxo C _2-50 aliphatic hydroxymonocarboxylic acids, preferably C _2-34 aliphatic hydroxymonocarboxylic acids such as chenodeoxycholic acid, glycocholic acid, lithocholic acid, hyodeoxycholic acid, ursodeoxycholic acid, apocholic acid, taurocholic acid More preferably, C _2-30 aliphatic hydroxy monocarboxylic acid, etc.), aromatic hydroxy monocarboxylic acid (eg, C _7-12 aromatic hydroxy monocarboxylic acid such as salicylic acid, oxybenzoic acid, gallic acid, etc.)], hydroxy Polica Rubonic acid [aliphatic hydroxypolycarboxylic acid (for example, C _2-10 aliphatic hydroxypolycarboxylic acid such as tartronic acid, tartaric acid, citric acid, malic acid and the like)] and the like.

  These carboxylic acids may form a salt, and may be anhydrides, hydrates, and the like. As described above, the carboxylic acid often does not form a salt (in particular, a salt with a basic compound such as a salt with an amine).

  The organic compound (B1) may be used alone or in combination of two or more.

Of these organic compounds (B1), aliphatic carboxylic acid (for example, C _1-24 aliphatic carboxylic acid, preferably C _1-20 aliphatic carboxylic acid, more preferably C _1-18 aliphatic carboxylic acid) or Hydroxy carboxylic acids such as aliphatic hydroxy carboxylic acids (aliphatic hydroxy monocarboxylic acids and aliphatic hydroxy polycarboxylic acids such as _C2-34 aliphatic hydroxy carboxylic acids) are preferred. Among the aliphatic hydroxycarboxylic acids, alicyclic hydroxycarboxylic acids (or hydroxycarboxylic acids having an alicyclic skeleton, for example, C _6-34 alicyclic hydroxycarboxylic acids such as cholic acid, preferably C _10-34 alicyclic hydroxycarboxylic acid, more preferably _C16-30 alicyclic hydroxycarboxylic acid) is preferable.

In addition, polycyclic aliphatic hydroxycarboxylic acids such as cholic acid (for example, condensed polycyclic aliphatic hydroxycarboxylic acids, preferably _C10-34 condensed polycyclic aliphatic hydroxycarboxylic acids, preferably _C14-34 condensed). Polycyclic aliphatic hydroxycarboxylic acids, more preferably _C18-30 condensed polycyclic aliphatic hydroxycarboxylic acids), dehydrocholic acid, colanic acid, and other polycyclic aliphatic carboxylic acids (eg, condensed polycyclic aliphatic acids) Aliphatic carboxylic acids, preferably C _10-34 condensed polycyclic aliphatic carboxylic acids, preferably C _14-34 condensed polycyclic aliphatic hydroxy carboxylic acids, more preferably C _18-30 condensed polycyclic aliphatic carboxylic acids ) polycyclic aliphatic carboxylic acids _{(e.g., C 10-50} condensed polycyclic aliphatic carboxylic acids such as, preferably _{C 12-40} condensed polycyclic aliphatic Carboxylic acid, more preferably C _14-34 condensed polycyclic aliphatic carboxylic acids, particularly C _18-30 condensed polycyclic aliphatic carboxylic acids), has a bulky structure, sintering of the metal nanoparticles This is preferable because it has a large effect of suppressing the above.

Furthermore, among these organic compounds (B1), a comparison with a free carboxyl group from the point that it can desorb or disappear from the metal particles at the firing temperature and improve the bonding strength of the inorganic material by forming a sintering site. Low molecular weight saturated aliphatic carboxylic acids, for example, C _1-16 alkanoic acids (alkane carboxylic acids) such as formic acid, acetic acid, propionic acid, butyric acid, valeric acid, preferably C _1-12 alkanoic acids (for example, C _1-6 alkanoic acid), more preferably C _1-4 alkanoic acid, in particular C _1-3 alkanoic acid (eg C _1-2 alkanoic acid).

  The molecular weight of the organic compound (B1) is, for example, 1000 or less (for example, about 46 to 900), preferably 800 or less (for example, about 50 to 700), and more preferably 600 or less (for example, about 100 to 500). It may be.

  Further, the pKa value of the organic compound (B1) may be, for example, about 1 or more (for example, about 1 to 10), preferably about 2 or more (for example, about 2 to 8).

(B2) Polymer Dispersant In the present invention, the protective colloid is constituted by combining the organic compound (B1) and the polymer dispersant (B2). By forming the protective colloid in such a combination, metal colloid particles containing metal nanoparticles with extremely few coarse particles can be obtained. In particular, in the present invention, the combination of the specific protective colloids can increase the proportion of metal nanoparticles even though the number of coarse particles is small, thereby improving the storage stability of the metal colloid particles (and dispersions thereof) in the paste. Is also excellent. The reason why such an excellent colloidal metal particle is obtained by the combination is not clear, but the following reasons are conceivable.

  First, the polymer dispersant is excellent in the effect of stabilizing the dispersion of relatively large particles due to its structure, but since the stabilization effect of relatively small particles is not sufficient, the concentration of the metal nanoparticle raw material is increased. Then, the generated particles cannot be sufficiently stabilized. On the other hand, the organic compound disperses and stabilizes relatively small particles generated at the initial synthesis stage of such nanoparticles. A synergistic action of the organic compound (B1) and the polymer dispersant (B2) that can generate metal nanoparticles while suppressing the formation of coarse particles even when the concentration of the metal nanoparticles is high. it is conceivable that.

  In addition, the protective colloid repeatedly adsorbs and desorbs on the surface of the metal nanoparticles on a short time scale. However, when the protective colloid is protected with a polymer dispersant, the adsorbed portion is desorbed momentarily. However, the steric hindrance is large, and even when desorbed, other groups are adsorbed on the surface of the metal nanoparticles instead of the groups involved in the adsorption, so that aggregation and sintering between the particles hardly occur. Therefore, while exhibiting good storage stability, due to its high protective ability and decomposition temperature, the sintering of the metal nanoparticles does not occur unless the firing temperature is high. Cannot be improved. On the other hand, an organic compound having a carboxyl group usually has a weak adsorptive power on the surface of metal nanoparticles and often has a low vaporization temperature. For this reason, it is easy to improve the bonding strength of inorganic materials due to desorption or disappearance from the surface of the metal nanoparticles by low-temperature firing, but the metal nanoparticles tend to aggregate and sinter even at low temperatures such as room temperature, and storage stability is improved. Since it is not sufficient, it is difficult to form a stable metal film on the layer surface between inorganic materials.

  Therefore, in the present invention, a polymer dispersant and an organic compound having a carboxyl group are combined. By such a combination, a portion where the polymer dispersant is adsorbed and a portion where the organic compound is adsorbed are formed on the surface of the metal nanoparticles. And, the portion where the polymer dispersant is adsorbed is stabilized by strong surface protection ability, and the storage stability is improved, while the portion where the organic compound is adsorbed is easily detached from the surface of the metal nanoparticles, It plays a role as a reaction site for low-temperature sintering. Such a reaction site is protected by the action of the polymer dispersant in an atmosphere of about room temperature, but starts a sintering reaction at a relatively low firing temperature (for example, several tens of degrees or more). It seems that the inorganic material can be firmly joined even by low-temperature firing. In particular, the higher the firing temperature, the higher the interparticle collision and sinterability than the protective ability of the polymer dispersant, so that the bonding force is further improved. Further, the polymer dispersant has an effect of improving the adhesion to the substrate, and in the joined body of the present invention, the residual amount of such a polymer dispersant can be reduced, and the volume between the inorganic material layers can be reduced. Since a dense and highly adhesive film with small shrinkage can be formed, the adhesiveness to the inorganic material is excellent and the inorganic materials can be firmly fixed.

  The polymer dispersant (or polymer type dispersant) (B2) is not particularly limited as long as it can coat the metal nanoparticles (A), but the amphiphilic polymer dispersant (or oligomer type dispersant). Can be suitably used.

  Examples of the polymer dispersant include polymer dispersants usually used for dispersing colorants in the paint and ink fields. Such dispersants include styrene resins (styrene- (meth) acrylic acid copolymers, styrene-maleic anhydride copolymers, etc.), acrylic resins ((meth) methyl acrylate- (meth) acrylic acid). Copolymers, (meth) acrylic acid resins such as poly (meth) acrylic acid), water-soluble urethane resins, water-soluble acrylic urethane resins, water-soluble epoxy resins, water-soluble polyester resins, cellulose derivatives (nitrocellulose; Cellulose ethers such as alkyl celluloses such as ethyl cellulose, alkyl-hydroxyalkyl celluloses such as ethyl hydroxyethyl cellulose, hydroxyalkyl celluloses such as hydroxyethyl cellulose and hydroxypropyl cellulose, and carboxyalkyl celluloses such as carboxymethyl cellulose. Tel, etc.), polyvinyl alcohol, polyalkylene glycol (liquid polyethylene glycol, polypropylene glycol, etc.), natural polymer (polysaccharides such as gelatin, dextrin, arabic gum, casein), polyethylene sulfonic acid or salt thereof, polystyrene sulfonic acid Or a salt thereof, a formalin condensate of naphthalenesulfonic acid, a nitrogen atom-containing polymer compound [for example, an amino group such as polyalkyleneimine (polyethyleneimine, etc.), polyvinylpyrrolidone, polyallylamine, polyether polyamine (polyoxyethylene polyamine, etc.) And the like.

  As a typical polymer dispersant (amphiphilic polymer dispersant), a resin (or water-soluble resin, water-dispersible resin) containing a hydrophilic unit (or hydrophilic block) composed of a hydrophilic monomer. Is included.

  Examples of the hydrophilic monomer include carboxyl group or acid anhydride group-containing monomers ((meth) acrylic monomers such as acrylic acid and methacrylic acid, unsaturated polycarboxylic acids such as maleic acid, and maleic anhydride. Acid), hydroxyl group-containing monomers (hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, vinylphenol, etc.) and other addition polymerization monomers; condensation monomers such as alkylene oxide (ethylene oxide, etc.) Etc. can be exemplified. The condensed monomer may form a hydrophilic unit by a reaction with an active group such as a hydroxyl group (for example, the hydroxyl group-containing monomer). The hydrophilic monomers may form a hydrophilic unit alone or in combination of two or more.

The polymer dispersant only needs to contain at least a hydrophilic unit (or hydrophilic block), and may be a homopolymer or a copolymer of a hydrophilic monomer (for example, polyacrylic acid or a salt thereof). It may be a copolymer of a hydrophilic monomer and a hydrophobic monomer, such as an exemplary styrene resin or acrylic resin. Examples of hydrophobic monomers (nonionic monomers) include (meth) acrylic acid esters [methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate. , (Meth) acrylic acid lauryl, (meth) acrylic acid C _1-20 alkyl such as stearyl (meth) acrylate, (meth) acrylic acid cycloalkyl such as cyclohexyl, (meth) acrylic acid phenyl, etc. (Meth) acrylic monomers such as aryl (meth) acrylate, benzyl (meth) acrylate, aralkyl (meth) acrylate such as 2-phenylethyl (meth) acrylate, etc .; styrene, α-methylstyrene, styrenic monomers such as vinyl toluene; _{α-C 2-20} olefin (ethylene , Propylene, 1-butene, isobutylene, 1-hexene, 1-octene, 1-dodecene, etc.) olefin monomers such as, vinyl acetate, and the like carboxylic acid vinyl ester monomers such as vinyl butyrate. Hydrophobic monomers may constitute a hydrophobic unit alone or in combination of two or more.

  When the polymeric dispersant is a copolymer (eg, a copolymer of a hydrophilic monomer and a hydrophobic monomer), the copolymer can be a random copolymer, an alternating copolymer, a block copolymer (eg, a hydrophilic block composed of hydrophilic monomers). And a copolymer composed of a hydrophobic block composed of a hydrophobic monomer), a star polymer (or a star block copolymer), a comb copolymer (or a comb graft copolymer), and the like. The structure of the block copolymer is not particularly limited, and may be a diblock structure, a triblock structure (ABA type, BAB type), or the like. In the comb copolymer, the main chain may be composed of the hydrophilic block, the hydrophobic block, or the hydrophilic block and the hydrophobic block.

  As described above, the hydrophilic unit may be composed of a condensation block such as a hydrophilic block (polyalkylene oxide such as polyethylene oxide or polyethylene oxide-polypropylene oxide) composed of alkylene oxide (such as ethylene oxide). it can. The hydrophilic block (such as polyalkylene oxide) and the hydrophobic block (such as polyolefin block) may be bonded via a linking group such as an ester bond, an amide bond, an ether bond, or a urethane bond. For example, the hydrophobic block (polyolefin, etc.) is modified with a modifying agent [unsaturated carboxylic acid or its anhydride ((anhydrous) maleic acid), lactam or aminocarboxylic acid, hydroxylamine, diamine, etc.]. Later, it may be formed by introducing a hydrophilic block. In addition, a polymer obtained from a monomer having a hydrophilic group such as a hydroxyl group or a carboxyl group (such as the hydroxyalkyl (meth) acrylate) is reacted (or bonded) with the condensed hydrophilic monomer (such as ethylene oxide). By doing so, a comb-type copolymer (comb-type copolymer having a main chain composed of a hydrophobic block) may be formed.

  Furthermore, the balance between hydrophilicity and hydrophobicity may be adjusted by using a hydrophilic nonionic monomer as a copolymerization component. Examples of such components include monomers having alkyleneoxy (particularly ethyleneoxy) units such as 2- (2-methoxyethoxy) ethyl (meth) acrylate and polyethylene glycol monomethacrylate (for example, a number average molecular weight of about 200 to 1,000). An oligomer etc. can be illustrated. Further, the balance between hydrophilicity and hydrophobicity may be adjusted by modifying (for example, esterifying) a hydrophilic group (such as a carboxyl group).

  The polymer dispersant (B2) may have a functional group. Examples of such functional groups include acid groups (or acidic groups such as carboxyl groups (or acid anhydride groups) and sulfo groups (sulfonic acid groups)), basic groups (such as amino groups), A hydroxyl group etc. are mentioned. These functional groups may be contained in the polymer dispersant (B2) alone or in combination of two or more.

  Among these functional groups, the polymer dispersant (B2) preferably has an acid group or a basic group, particularly a free carboxyl group.

  Further, when the polymer dispersant (B2) has an acid group (such as a carboxyl group), at least a part or all of the acid group (such as a carboxyl group) is a salt (a salt with an amine, a metal salt, or the like). In particular, in the present invention, an acid group such as a carboxyl group (especially all carboxyl groups) is a salt [especially a salt with a basic compound (a salt with an amine or an amine salt). Etc.]] [that is, a polymer dispersant having a free acid group (particularly a carboxyl group)] can be suitably used.

  In the polymer dispersant (B2) having an acid group (especially a free carboxyl group), the acid value has no lower limit as long as it can protect the surface of the nanoparticle produced when the nanoparticle is produced, but the lower one Is preferred. If the acid value is too high, a large number of functional groups derived from the polymer are adsorbed or present on the surface of the nanoparticle, so that the number of sintering points decreases, and there is a possibility of inhibiting the sintering between the nanoparticles. The acid value can be selected from the range of, for example, 1 mgKOH / g or more (for example, about 2 to 1500 mgKOH / g), particularly 10 mgKOH / g or more (for example, about 12 to 900 mgKOH / g). In particular, when the polymer dispersant (B2) having an acid group (particularly a carboxyl group) is a compound having a hydrophilic unit and a hydrophobic unit, the acid value is 1 mgKOH / g or more (for example, 2 to 100 mgKOH / g), preferably 3 mgKOH / g or more (for example, about 4 to 90 mgKOH / g), more preferably 5 mgKOH / g or more (for example, about 6 to 80 mgKOH / g), particularly 7 mgKOH / g or more (for example, 8 to 70 mgKOH). / G) or about 3 to 50 mg KOH / g (for example, 5 to 30 mg KOH / g). In the polymer dispersant (B2) having an acid group, the amine value may be 0 (or almost 0).

  In the polymer dispersant, the position of the functional group as described above is not particularly limited, and may be a main chain, a side chain, or a main chain and a side chain. Good. Such a functional group may be, for example, a hydrophilic monomer or a functional group derived from a hydrophilic unit (for example, a hydroxyl group), or a copolymerizable monomer having a functional group (for example, maleic anhydride). It can also be introduced into the polymer by copolymerization.

  The polymer dispersant (B2) may be used alone or in combination of two or more.

  As the polymer dispersant, a polymer dispersant (high molecular weight pigment dispersant) described in JP-A No. 11-80647 may be used.

  The polymer dispersant may be synthesized and used, or a commercially available product may be used. Specific examples of commercially available polymer dispersants (or dispersants composed of at least an amphiphilic dispersant) include Solsperse 13240, Solsperse 13940, Solsperse 32550, Solsperse 31845, Solsperse 24000, Solsperse 26000, Solsperse series such as Solsperse 27000, Solsperse 28000, Solsperse 41090 [manufactured by Avicia Co., Ltd.]; Dispersic 160, Dispersic 161, Dispersic 162, Dispersic 163, Dispersic 164, Dispersic 166, Dispersic 170, Dispers Big 180, Dispersic 182, Dispersic 184, Dispersic 190, Dispersic 191, Dispersic 92, Dispersic 193, Dispersic 194, Dispersic 2001, Dispersic 2010, Dispersic 2050, Dispersic 2090, Dispersic 2091, etc. Dispersic series [manufactured by BYK Chemie Corp.]; EFKA-46, EFKA-47, EFKA-48, EFKA-49, EFKA-1501, EFKA-1502, EFKA-4540, EFKA-4550, polymer 100, polymer 120, polymer 150, polymer 400, polymer 401, polymer 402, polymer 403, polymer 450, polymer 451 , Polymer 452, polymer 453 [manufactured by EFKA Chemical Co., Ltd.]; Ajisper PB711, Azisper PAl11, Azisper PB811, Ajisper P 821, Ajisper series such as Ajisper PW911 [manufactured by Ajinomoto Co., Inc.]; Floren DOPA-158, Floren DOPA-22, Floren DOPA-17, Floren TG-700, Floren TG-720W, Floren-730W, Floren-740W, Florene series such as Floren-745W [manufactured by Kyoeisha Chemical Co., Ltd.]; John Kuryl series such as John Kuril 678, John Kuryl 679, and John Kuryl 62 [Johnson Polymer Co., Ltd.].

  Among these, polymer dispersants having typical acid groups include poly (meth) acrylic acids [or polyacrylic resins such as poly (meth) acrylic acid and (meth) acrylic acid. Polymers mainly composed of (meth) acrylic acid, such as copolymers with monomers (for example, (meth) acrylate, maleic anhydride, etc.), and salts thereof (for example, alkali metal salts such as sodium polyacrylate) Etc.), Dispersic 190, Dispersic 194 and the like. Examples of the polymer dispersant having a typical basic group (amino group) include polyalkyleneimine (polyethyleneimine etc.), polyvinylpyrrolidone, polyallylamine, polyether polyamine (polyoxyethylene polyamine etc.) and the like. .

  The number average molecular weight of the polymer dispersant (B2) can be selected from the range of 1000 to 1000000 (for example, 1200 to 800000), for example, 1500 to 500000 (for example, 1500 to 100000), preferably 2000 to 80000 (for example, 2000 to 60000), more preferably 3000 to 50000 (for example, 5000 to 30000), particularly about 7000 to 20000.

  In the metal colloid particles, the ratio of the protective colloid (B) (total amount of the organic compound (B1) and the polymer dispersant (B2)) is, for example, in terms of solid content, with respect to 100 parts by mass of the metal nanoparticles (A). 0.1-100 parts by mass (for example, 0.5-80 parts by mass), preferably 1.0-60 parts by mass (for example, 1.5-50 parts by mass), more preferably 2-40 parts by mass ( For example, it may be about 3 to 30 parts by mass), particularly about 4 to 25 parts by mass (for example, 5 to 20 parts by mass), and usually about 10 to 50 parts by mass. In particular, in the metal colloid particles of the present invention, the proportion of the protective colloid (B) is 0.5 to 20 parts by mass (for example, 0.8 to 18 parts by mass) with respect to 100 parts by mass of the metal nanoparticles (A). 1 to 15 parts by mass, preferably 1.2 to 12 parts by mass (for example, 1.5 to 10 parts by mass). In the present invention, since the protective colloid is constituted by the specific combination, even a relatively small amount of the protective colloid as described above can be formed into metal nanoparticles with few coarse particles.

  In the metal colloidal particles, the ratio of the organic compound (B1) is, for example, 0.05 to 70 parts by mass (for example, 0.8%) with respect to 100 parts by mass of the metal nanoparticles (A) in terms of solid content. 1 to 50 parts by mass), preferably 0.5 to 40 parts by mass (for example, 1 to 30 parts by mass), and more preferably about 2 to 20 parts by mass (for example, 3 to 15 parts by mass). In particular, in the metal colloid particles of the present invention, the proportion of the organic compound (B1) is 0.05 to 10 parts by mass (for example, 0.1 to 8 parts by mass) with respect to 100 parts by mass of the metal nanoparticles (A). The amount may be preferably about 0.12 to 7 parts by mass (for example, 0.15 to 5 parts by mass), more preferably about 0.18 to 4 parts by mass (for example, 0.2 to 3 parts by mass).

  In the metal colloid particles, the ratio of the polymer dispersant (B2) is, for example, 0.01 to 50 parts by mass (for example, with respect to 100 parts by mass of the metal nanoparticles (A) in terms of solid content). 0.05 to 30 parts by mass), preferably 0.1 to 30 parts by mass (for example, 0.5 to 20 parts by mass), more preferably about 1 to 15 parts by mass (for example, 2 to 10 parts by mass). May be. In particular, in the metal colloid particles of the present invention, the ratio of the polymer dispersant (B2) is 0.05 to 15 parts by mass (for example, 0.1 to 12 parts by mass with respect to 100 parts by mass of the metal nanoparticles (A)). Part), preferably 0.12 to 10 parts by mass (for example, 0.15 to 8 parts by mass), more preferably about 0.18 to 7 parts by mass (for example, 0.2 to 6 parts by mass). Good.

  Furthermore, in the metal colloidal particles, the ratio of the organic compound (B1) to the polymer dispersant (B2) (the ratio of the solid content when a solvent is included) is the former / the latter (mass ratio) = 99/1 to 1. / 99 (for example, 95/5 to 5/95), preferably 85/15 to 10/90 (for example, 75/25 to 15/85), more preferably 70/30 to 20/80 (for example, 60 / 40-25 / 75), especially 55 / 45-30 / 70 (for example, 50 / 50-35 / 65). In particular, in the metal colloid particles, the ratio of the organic compound (B1) and the polymer dispersant (B2) is the former / the latter (mass ratio) = 97/3 to 1/99 (for example, 96/4 to 1/99). ), Preferably 95/5 to 2/98 (e.g. 93/7 to 2/98), more preferably 92/8 to 3/97 (e.g. 90/10 to 3/97), usually 87/13 to It may be about 3/97 (for example, 86/14 to 4/96).

  In addition, the metal colloid particle of this invention should just contain the said protective colloid (B) at least as a protective colloid, and may contain the other protective colloid component. The other protective colloid component may be an inorganic compound, but is usually an organic compound.

Other protective colloid components include, for example, oxygen atom-containing organic compounds {eg, alcohols [eg, alkanols (C _6-20 alkane monools such as hexanol, octanol, decanol, dodecanol, octadecanol, etc.), cycloalkanol] (Such as cyclohexanol), aralkyl alcohols, polyhydric alcohols, etc.], ketones [eg alkanones, cycloalkanones, diketones (β-diketones such as acetylacetone)], esters (eg, Fatty acid esters, glycol ether esters, etc.), aldehydes (C _6-20 aliphatic aldehydes such as caprylaldehyde, lauryl aldehyde, palmitoaldehyde, stearyl aldehyde, etc.)}, organic compounds containing sulfur atoms [for example, Sulfoxides, sulfonic acids (eg, arene sulfonic acids such as alkane sulfonic acid, benzene sulfonic acid, toluene sulfonic acid, etc.)] and the like. These other protective colloids may be used alone or in combination of two or more.

  The ratio of the other protective colloid is, for example, 0.1 to 100 parts by mass, preferably 0.5 to 50 parts by mass, and more preferably about 1 to 30 parts by mass with respect to 100 parts by mass of the protective colloid (B). It may be.

  The ratio of the organic compound (B1), the polymer dispersant (B2), etc. in the metal colloidal particles should be measured by a conventional method, for example, thermal analysis (for example, thermal mass / differential thermal simultaneous analysis, etc.). Can do.

(Dispersion medium)
The dispersion medium is not particularly limited as long as it is a solvent that generates sufficient viscosity in the paste (paste-like dispersion) by combining with the metal colloid particles (or metal nanoparticles), and a general-purpose solvent can be used. In addition, a solvent may be newly mixed, may be comprised with the solvent used in manufacture of the below-mentioned metal colloid particle, and may combine these.

  The solvent is not particularly limited as long as the metal colloid particles can be dispersed. Depending on the type of protective colloid, the solvent may be a polar solvent (water-soluble solvent) or a hydrophobic solvent (water-insoluble solvent). Also good.

Examples of the polar solvent include water, alcohols (C _1-4 alkanols such as methanol, ethanol, propanol, isopropanol, and butanol), aliphatic polyhydric alcohols (ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, Polyethylene glycol, glycerol, etc.), amides (formamide, acylamides such as acetamide, N-methylformamide, N-methylacetamide, N, N-dimethylformamide, N-mono or N, N, such as N, N-dimethylacetamide - di C _1-4 acyl amides, etc.), ketones (such as acetone), ethers (dioxane, tetrahydrofuran, etc.), organic carboxylic acids (such as acetic acid), cellosolves (methyl cellosolve, Echirusero Such as C _1-4 alkyl cellosolve such as lube), such as C _1-4 alkyl cellosolve acetates such as cellosolve acetates (ethyl cellosolve acetate), carbitol (methyl carbitol, ethyl carbitol, propyl carbitol, butyl C _1-4 alkyl carbitols such as carbitol), halogenated hydrocarbon solvents (halogenated hydrocarbons such as methylene chloride, chloroform, dichloroethane, etc.) and the like. These polar solvents can be used alone or in combination of two or more. The polar parameters of these polar solvents are usually in the range of the polar parameters described later in many cases.

  Examples of the hydrophobic solvent include hydrocarbons (aliphatic hydrocarbons such as hexane, trimethylpentane, octane, decane, dodecane, and tetradecane; alicyclic hydrocarbons such as cyclohexane; aromatic carbonization such as toluene and xylene. Hydrogens: halogenated hydrocarbons such as dichloromethane and trichloroethane), esters (such as methyl acetate and ethyl acetate), ketones (such as methyl ethyl ketone and methyl isobutyl ketone), ethers (such as diethyl ether and dipropyl ether) Can be illustrated. These hydrophobic solvents can be used alone or in combination of two or more.

  The dispersion medium is preferably composed of at least a polar solvent (particularly a non-aromatic polar solvent or an aliphatic polar solvent). The polarity parameter (polarity parameter by Snyder) of such a solvent may be, for example, 2.8 to 11, preferably 3 to 10.5, and more preferably about 3.1 to 10.2.

  In the present invention, the solvent is preferably a water-soluble solvent such as water and / or alcohols because it has a low environmental burden and is easy to handle, and imparts viscosity to the paste as a bonding agent. In particular, aliphatic polyhydric alcohols such as ethylene glycol and glycerin are preferable.

  In the paste containing such a dispersion medium and metal colloid particles, the metal colloid particles (or metal nanoparticles (A)) have a high dispersibility with respect to the dispersion medium and have a high dispersion stability over a long period of time. Show. The concentration of the metal nanoparticles (A) in the paste is, for example, about 30 to 95% by mass, preferably 50 to 93% by mass, more preferably 70 to 90% by mass (particularly 80 to 90% by mass). Also good.

  The bonding agent composed of such a paste is excellent in long-term stability (storage stability) without causing sedimentation or the like even if it contains the metal nanoparticles (A) at a high concentration. Therefore, for example, after the paste is stored for a long period of time, a uniform sintered film can be formed between the layers of the inorganic material, and the bonding strength of the inorganic material can be improved.

  In the paste, the metal nanoparticles (A) coated with the protective colloid are also nanometer-sized, and the average particle size (average primary particle size) can be selected from the same range as described above.

  In the bonding agent for inorganic materials according to the present invention, conventional additives such as binder resins (such as hydrophilic polymers such as polyvinyl alcohol and polyethylene glycol), colorants (such as dyes and pigments), and hue improvements are used depending on the application. Agent, dye fixing agent, gloss imparting agent, metal corrosion inhibitor, stabilizer (antioxidant, UV absorber, etc.), surfactant or dispersant (anionic surfactant, cationic surfactant, nonionic interface) Active agents, amphoteric surfactants, etc.), dispersion stabilizers, thickeners or viscosity modifiers, moisturizers, thixotropic agents, leveling agents, antifoaming agents, bactericides, fillers, etc. Good. These additives can be used alone or in combination of two or more.

  In addition, the solid content concentration of metal nanoparticles (A) (or the concentration of metal nanoparticles (A) in metal colloid particles) with respect to the entire solid content of the paste (which constitutes the paste) is, for example, 50% by mass or more (for example, 55-99.5% by mass), preferably 60% by mass or more (eg, 70-99% by mass), more preferably 80% by mass or more (eg, 85-98.5% by mass), usually 90-99% by mass. It may be a degree.

[Method for producing bonding agent for inorganic material]
In the bonding agent for inorganic materials according to the present invention, the metal colloid particles are obtained by a conventional method, for example, by applying a metal compound corresponding to the metal nanoparticles (A) to the protective colloid (B) (and the other protection if necessary). Colloid) and a reducing agent in the presence of a reducing agent.

  The metal compound corresponding to the metal nanoparticles (A) includes, for example, metal oxide, metal hydroxide, metal sulfide, metal halide, metal acid salt [metal inorganic acid salt (sulfate, nitrate, perchloric acid). Oxo acid salts such as salts), metal organic acid salts (such as acetates), and the like]. In addition, the form of the metal salt may be any of a single salt, a double salt, or a complex salt, and may be a multimer (for example, a dimer). These metal compounds can be used alone or in combination of two or more. Among these metal compounds, metal halides, metal acid salts [metal inorganic acid salts (such as sulfates, nitrates, perchlorates, etc.), metal organic acid salts (such as acetates), etc.] Often used. These metal compounds may be used by dissolving or dispersing in a solvent (for example, in the form of a solution of an aqueous solvent such as an aqueous solution).

  Examples of the reducing agent include conventional components such as sodium borohydride (sodium borohydride, sodium cyanoborohydride, sodium triethylborohydride, etc.), lithium aluminum hydride, hypophosphorous acid or a salt thereof (sodium). Salts), boranes (diborane, dimethylamine borane, etc.), hydrazine, formalin, amines, alcohols (the alcohols exemplified above, such as ethylene glycol), carboxylic acids having a phenolic hydroxyl group (eg, tannic acid) And the like.

Examples of amines include aliphatic amines (for example, propylamine, butylamine, hexylamine, diethylamine, dipropylamine, dimethylethylamine, diethylmethylamine, triethylamine, ethylenediamine, N, N, N ′, N′-tetramethylethylenediamine). 1,3-diaminopropane, alkaneamines such as N, N, N ′, N′-tetramethyl-1,3-diaminopropane; polyalkylene polyamines such as triethylenetetramine and tetraethylenepentamine), and alicyclic rings Formula amines (eg piperidine, N-methylpiperidine, piperazine, N, N′-dimethylpiperazine, pyrrolidine, N-methylpyrrolidine, morpholine, etc.), aromatic amines (eg aniline, N-methylaniline, N, N-dimethyl Nilin, toluidine, anisidine, phenetidine, etc.), araliphatic amines (for example, benzylamine, N-methylbenzylamine, N, N-dimethylbenzylamine, phenethylamine, xylylenediamine, N, N, N ′, N ′ Aralkylamines such as tetramethylxylylenediamine), alcohol amines [especially alkanolamines such as methylaminoethanol, dimethylaminoethanol (2- (dimethylamino) ethanol), ethanolamine, diethanolamine, triethanolamine, methyl diethanolamine, propanolamine, 2- (3-aminopropyl amino) ethanol, butanol amine, hexanol amine, _{C 2-10} alkanol amines such as dimethylamino propanol, preferably May be mentioned is _{C 2-6} alkanolamine.

  Among these, sodium borohydride, tertiary amine (for example, tertiary alkanolamine such as 2- (dimethylamino) ethanol and N-methyldiethanolamine), ethylene glycol, tannic acid and the like can be preferably used. In view of safety, amines, particularly alcohol amines such as alkanolamines are preferred. Alkanolamines are usually water-soluble in many cases, and are suitable when water or an aqueous solvent is used as a solvent.

  These reducing agents can be used alone or in combination of two or more.

  The amount of the reducing agent used is 1 to 30 mol (for example, 1.2 to 20 mol), preferably 1.5 to 15 mol, based on 1 equivalent (or 1 mol) of the metal compound in terms of metal atom. Preferably, it may be about 2 to 10 mol, and usually about 1 to 5 mol.

  The reduction reaction can be performed by a conventional method, for example, at a temperature of about 10 to 75 ° C. (for example, about 15 to 50 ° C., preferably about 20 to 35 ° C.). The atmosphere of the reaction system may be air, an inert gas (such as nitrogen gas), or an atmosphere containing a reducing gas (such as hydrogen gas). Moreover, you may perform reaction under stirring (or stirring) normally.

  In addition, the solvent (for example, water etc.) similar to the above can be used for the reaction solvent. As the reaction solvent, the solvent constituting the paste may be used, or a solvent different from the solvent constituting the paste may be used. Specifically, the reaction solvent can be selected from the polar solvent and the hydrophobic solvent according to the type of the protective colloid. Usually, when the protective colloid is a water-soluble compound, a polar solvent such as water is used. Often used. The polar solvent may be derived from a component added to the reaction system, for example, a solvent such as a reducing agent. On the other hand, when the protective colloid is a water-insoluble compound, a hydrophobic solvent such as aliphatic hydrocarbons (such as trimethylpentane) is often used, and if necessary, a hydrophobic solvent and a polar solvent (for example, ethanol, Alcohols such as isopropanol, ketones such as acetone, cyclic ethers such as dioxane and tetrahydrofuran, and amides such as dimethylacetamide) may be used.

  Of these reaction solvents, a polar solvent containing at least water may be used from the viewpoints of environmental conservation and simplicity. Furthermore, alcohols (particularly, aliphatic polyhydric alcohols such as ethylene glycol and glycerin) may be combined with water from the viewpoint of suppressing evaporation of the solvent, depending on the application. The proportion of alcohol is, for example, about 0.1 to 50 parts by mass, preferably 1 to 30 parts by mass, and more preferably about 3 to 20 parts by mass (particularly 5 to 15 parts by mass) with respect to 100 parts by mass of water. There may be.

  The concentration of the metal compound in the reaction solvent is, for example, 5% by mass or more (for example, 6 to 50% by mass), preferably 8% by mass or more (for example, 9 to 40% by mass), in terms of metal mass. Preferably, the concentration may be as high as 10% by mass or more (for example, 12 to 30% by mass), usually about 5 to 30% by mass. In the present invention, even when the reaction is performed at such a high concentration, metal nanoparticles can be obtained efficiently while suppressing the generation of coarse particles.

  The pH of the reaction system may be adjusted according to the type of reaction solvent.

  The pH is adjusted by a conventional method, for example, an acid (an inorganic acid such as hydrochloric acid, sulfuric acid, nitric acid or phosphoric acid, an organic acid such as acetic acid), an alkali [an inorganic base such as sodium hydroxide or ammonia, or an amine (for example, an alkyl). Bases such as organic bases such as tertiary amines such as amines and alkanolamines].

  After completion of the reduction reaction, the reaction mixture is concentrated and purified by conventional methods (for example, centrifugation, membrane filter, ultrafiltration, etc.), so that the metal colloid has dispersibility in the solvent. Particles can be prepared. In the present invention, since the protective colloid is constituted by the specific combination, as described above, even with a relatively small amount of protective colloid, it is possible to obtain a metal nanoparticle with few coarse particles. Without it, metal colloidal particles can be prepared. Further, the obtained dispersion liquid containing the metal colloid particles and the solvent may be used as it is or concentrated to form the paste. The solvent used in the reaction is removed from the obtained dispersion liquid containing the metal colloid particles and the solvent to obtain a new paste. A different type of solvent (other additives as required) may be added to prepare a new paste. Further, a new same or different solvent or additive may be added to the paste.

[Inorganic material bonded body and bonding method]
The bonding agent obtained by the manufacturing method is used for bonding inorganic materials. The inorganic material bonded body of the present invention is obtained by sintering the inorganic material bonding agent by interposing the inorganic material bonding agent of the present invention between the inorganic material (C1) and the inorganic material (C2). Can be obtained.

As the inorganic material, an inorganic material such as glass or carbon material may be used. However, since the paste is composed of metal nanoparticles, at least the bonding surface contains a metal from the point of improving the bonding force (or A material in which metal is present on the bonding surface (particularly a material in which substantially the entire bonding surface is made of metal) is preferable. Examples of the metal include simple metals, alloys, and metal compounds exemplified in the section of metal nanoparticles (A). Of these, a simple metal or an alloy is preferable, and a simple cubic lattice is used as a combination of a simple metal constituting the metal nanoparticle and a simple metal constituting the bonding surface of the inorganic material (or each simple metal constituting the alloy). The structure (sc), the face-centered cubic lattice structure (fcc), the body-centered cubic lattice structure (bcc), the hexagonal close-packed (filled) structure (hcp), etc. A combination of the same crystal structures (for example, fcc, bcc, etc.) is preferable. The lattice constant is also preferably approximated, and the lattice constant of the single metal constituting the joint surface is 0.8 to 1.2 times the lattice constant of the single metal constituting the metal nanoparticle (particularly It may be about 0.86 to 1.17 times. When the lattice constants of both are adjusted to such a range, the mutual crystal lattices are matched, so that it is presumed that a good metal bond is formed at the interface. In addition, the atomic radius of the simple metal constituting the bonding surface is about 0.8 to 1.2 times (0.85 to 1.15 times) the atomic radius of the simple metal constituting the metal nanoparticle. There may be. When the atomic radii of both are adjusted to such a range, the mutual solubility of the atoms is large, so that they are easily dissolved at the interface. For example, when the metal nanoparticles are composed of silver (fcc, lattice constant a: 3.614 Å (angstrom), atomic radius: 1.442 Å), the metal constituting the joint surface is at least silver or gold ( fcc, lattice constant a: 4.078 Å, atomic radius: 1.439 な ど) and other noble metals (particularly Group 1B metal of the periodic table), copper (fcc, lattice constant a: 3.614 Å, atomic radius: 1.276 Å), Metals (metal simple substance and metal alloy) containing nickel (fcc, lattice constant a: 3.524Å, atomic radius: 1.244Å), etc., especially noble metal simple substance (for example, gold, palladium (fcc, lattice constant a: 3.89Å) , Atomic radius: 1.373Å) simple substance). That is, when the substrate is made of a metal compound such as aluminum nitride (AlN) or aluminum oxide (Al ₂ O ₃ ) or a nonmetal, it is preferable to treat the bonding surface with a single metal or a metal alloy. . Examples of the surface treatment include sputtering and plating with a metal containing a noble metal. When the joint surface of the inorganic material includes a metal, the metal constituting the metal nanoparticle may be different from the metal included in the inorganic material, but is preferably the same or a similar metal.

  The inorganic material (C1) and the inorganic material (C2) to be joined may be different materials or the same kind of materials.

  The shape of the inorganic material is not particularly limited. For example, the shape in which the contact area between the materials to be joined increases, for example, the shape in which the joining surface is flat (usually a plate or sheet shape, a film shape, a foil shape), etc. It may be wire-like or linear.

The coating amount of the bonding agent for inorganic material (coating amount before drying) can be appropriately selected according to the use and size of the inorganic material to be bonded. From the point of strong bonding, for example, 10 to 100 mg / cm ² , Preferably it is 20-80 mg / cm < ² >, More preferably, it is about 30-70 mg / cm < ² >.

  The application method is not particularly limited, and conventional methods such as a method using a coater, spray coating, dipping, and the like can be used.

The firing temperature for sintering the bonding agent may be, for example, about 150 to 500 ° C, preferably about 200 to 450 ° C, and more preferably about 250 to 400 ° C (particularly 300 to 380 ° C). Moreover, before baking, you may preheat at the temperature of about 80-200 degreeC (especially 100-150 degreeC), for example. The firing may be pressurized, for example, a load of about 1 to 500 g / cm ² , preferably 3 to 300 g / cm ² , more preferably 5 to 100 g / cm ² (particularly 10 to 50 g / cm ² ). You may bake in the state which provided. In the present invention, the inorganic material can be firmly joined even when firing at such a relatively low temperature and low pressure. The firing may be performed in air or in an inert gas such as nitrogen gas or argon gas.

  The firing time (heating time) may be, for example, 1 minute to 10 hours, preferably 20 minutes to 5 hours, more preferably about 30 minutes to 3 hours, depending on the firing temperature and the like.

  Although the thickness of the sintered film (metal film) formed between the layers of the inorganic material after firing can be appropriately selected from the range of about 1 μm to 1 cm depending on the application, for example, 5 to 300 μm, preferably 10 to 200 μm, More preferably, it is about 30-100 micrometers.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

Example 1
(Synthesis of colloidal metal particles)
66.8 g of silver nitrate, 10 g of acetic acid (manufactured by Wako Pure Chemical Industries, Ltd., boiling point 118 ° C., carbon number 2) as the organic compound (B1) having a carboxyl group, and polyacrylic acid (Japanese sum) as the polymer dispersant (B2) Kogure Pharmaceutical Co., Ltd., degree of polymerization 5000, acid value 780 mg KOH / g) 3.0 g was charged into ion-exchanged water 1000 g and vigorously stirred. To this was added 100 g of 2-dimethylaminoethanol (manufactured by Wako Pure Chemical Industries, Ltd.), followed by heating and stirring at 70 ° C. for 2 hours. This reaction product was centrifuged at 7000 rpm for 1 hour using a high-speed centrifuge (manufactured by Kokusan Co., Ltd., H-200 SERIES), and silver colloid particles (primary particles) in which silver nanoparticles were protected by a protective colloid. The precipitate in which the diameter was 1 to 100 nm and the number average particle diameter was 20 nm was collected. The amount of protective colloid (dispersant) (B) contained in the silver colloid particles was measured by TG-DTA (calculated from the mass decrease when the temperature was raised from 30 ° C. to 550 ° C. at a rate of 10 ° C. per minute). However, it was 5.3 mass%, and (B1) / (B2) (mass ratio) was 25/75. The ratio of (B1) / (B2) is calculated by first calculating the amount of (B1) from the mass decrease from 30 ° C. to 200 ° C., and calculating (B2) from the formula [(B)-(B1)] It calculated | required from these values (B1) (B2).

(Bonding of gold substrates)
Ethylene glycol (polarity parameter 6.9) was added to the obtained silver colloidal particles to prepare a joining paste having a silver concentration of 85% by weight. After 50 mg of this bonding paste was applied onto a gold substrate (1 × 1 cm), an aluminum nitride substrate with gold sputtered on its surface (a substrate sputtered in the order of titanium, platinum, and gold on the aluminum nitride substrate ( The same applies to the following, and 0.4 × 0.4 cm). A 20 g weight was placed on the aluminum nitride substrate, a load was applied, the temperature was raised from room temperature to 350 ° C. at a rate of 20 ° C./min, and then firing was performed while maintaining 350 ° C. for 1 hour. The formed silver film had a thickness of 50 μm.

(Measurement of shear strength)
For a bonded substrate, a large-area substrate (gold substrate) is fixed, and the terminal is brought into contact with the aluminum nitride substrate adhered thereto, and the bonding force when the small-area substrate peels is shearing force. As measured. A testing machine for measuring the bonding force is a universal bond tester series manufactured by Daisy Corporation. The shear strength of this substrate was 15 MPa.

Example 2
In the synthesis of metal colloidal particles, the same as in Example 1 except that propionic acid (manufactured by Wako Pure Chemical Industries, Ltd., boiling point 141 ° C., carbon number 3) is used as the organic compound (B1) having a carboxyl group instead of acetic acid. As a result of joining the substrates and measuring the shear strength, the result was 13 MPa. In addition, the quantity of the protective colloid (B) was 5.8 mass%, and (B1) / (B2) (mass ratio) was 20/80.

Example 3
In the synthesis of metal colloidal particles, in the same manner as in Example 1 except that cholic acid (manufactured by Wako Pure Chemical Industries, Ltd., decomposition temperature 198 ° C.) was used instead of acetic acid as the organic compound (B1) having a carboxyl group, The substrates were joined and the shear strength was measured and found to be 10 MPa. The amount of protective colloid (B) was 8.2% by mass, and (B1) / (B2) (mass ratio) was 28/72.

Example 4
In the synthesis of metal colloidal particles, Dispersic 190 (manufactured by Big Chemie, amphiphilic dispersant having a polyethylene oxide chain which is a hydrophilic unit and an alkyl group which is a hydrophobic unit, as the polymer dispersant (B2), acid value The substrate was bonded and the shear strength was measured in the same manner as in Example 2 except that 7.2 g (10 mg KOH / g, containing 60% water) was used. As a result, the shear strength was 20 MPa. The amount of protective colloid (B) was 5.5% by mass, and (B1) / (B2) (mass ratio) was 18/82. When the storage stability of the reaction product before centrifugation was confirmed, generation of large particles of several hundred nm or more was not recognized even at room temperature storage.

Example 5
Example 4 except that formic acid (manufactured by Wako Pure Chemical Industries, Ltd., boiling point 100.7 ° C., carbon number 1) was used in place of propionic acid as the organic compound (B1) having a carboxyl group in the synthesis of metal colloidal particles. In the same manner as described above, the substrates were joined and the shear strength was measured. The amount of protective colloid (B) was 4.3% by mass, and (B1) / (B2) (mass ratio) was 15/85. When the storage stability of the reaction product before centrifugation was confirmed, generation of large particles of several hundred nm or more was not recognized even at room temperature storage.

Example 6
In the synthesis of metal colloidal particles, the substrate was joined and the shear strength was measured in the same manner as in Example 4 except that cholic acid was used instead of propionic acid as the organic compound (B1) having a carboxyl group. Met. The amount of protective colloid (B) was 7.3% by mass, and (B1) / (B2) (mass ratio) was 28/72. When the storage stability of the reaction product before centrifugation was confirmed, generation of large particles of several hundred nm or more was not recognized even at room temperature storage.

Example 7
In the synthesis of metal colloidal particles, a substrate was prepared in the same manner as in Example 4 except that acetic acid was used instead of propionic acid as the organic compound (B1) having a carboxyl group, and the amount of Dispersic 190 used was 2.12 g. As a result of bonding and measuring the shear strength, it was 30 MPa. The amount of protective colloid (B) was 2.4% by mass, and (B1) / (B2) (mass ratio) was 35/65. When the storage stability of the reaction product before centrifugation was confirmed, generation of large particles of several hundred nm or more was not recognized even at room temperature storage.

Example 8
After applying 10 mg of the bonding paste prepared in Example 7 on a palladium substrate (1 × 1 cm), the bonding paste was applied on an aluminum nitride substrate (0.2 × 0.2 cm) with gold sputtered on the surface. I caught it. The sample was heated from room temperature to 350 ° C. at a rate of 20 ° C./min without applying a load, and then calcined by maintaining 350 ° C. for 14 minutes. The formed silver film had a thickness of 30 μm. As a result of joining the substrates and measuring the shear strength, it was 25 MPa.

Example 9
After 0.6 mg of the bonding paste prepared in Example 7 was applied on an oxygen-free copper substrate (1 × 1 cm), the bonding paste was sandwiched between the oxygen-free copper substrate (0.2 × 0.2 cm). . The sample was heated from room temperature to 350 ° C. at a rate of 20 ° C./min without applying a load, and then calcined by maintaining 350 ° C. for 14 minutes. The formed silver film had a thickness of 15 μm. As a result of joining the substrates and measuring the shear strength, it was 15 MPa.

Example 10
After 0.6 mg of the bonding paste prepared in Example 7 was applied on a copper electroplated nickel substrate (1 × 1 cm), the copper electroplated nickel substrate (0.25 × 0.25 cm). ) Sandwiched the bonding paste. The sample was heated from room temperature to 350 ° C. at a rate of 20 ° C./min without applying a load, and then calcined by maintaining 350 ° C. for 14 minutes. The formed silver film had a thickness of 15 μm. As a result of joining the substrates and measuring the shear strength, it was 7 MPa.

Comparative Example 1
As a silver nitrate (2.5 g) and a dispersant (protective colloid) (B), 4.9 g of octylamine and 3.1 g of propionic acid were added to 1 liter of trimethylpentane, and stirred and mixed to dissolve. To this mixed solution, 1.0 liter of a propanol solution containing 0.03 mol / liter sodium borohydride was added dropwise over 1 hour to reduce silver. Furthermore, it stirred for 3 hours and obtained the black liquid. After the obtained black liquid was concentrated by an evaporator, 2.0 liters of methanol was added to the concentrated liquid to form a brown precipitate, and then the precipitate was collected by suction filtration. The produced precipitate was redispersed in trimethylpentane, filtered, and dried to obtain silver nanoparticles as a black solid. The number average particle size of the core part of the obtained silver nanoparticles was 4 nm, and the amount of the dispersant (B) was 15.5% by mass. The silver nanoparticles were dispersed in tetradecane to prepare a paste having a silver concentration of 60% by mass, and left at room temperature for 1 week to confirm the storage stability. As a result, the nanoparticles were sintered and large particles of several hundred nm or more were sintered. It was possible to observe the growth up to 2 hours, and the stability over time was poor.

  The bonding agent for inorganic materials of the present invention can be used as a bonding agent capable of firmly bonding inorganic materials such as metal materials, for example, inorganic substrates such as metal plates.

Claims (7)

A bonding agent for inorganic materials composed of metal colloid particles and a paste containing a dispersion medium of the metal colloid particles,
The metal colloid particles are composed of metal nanoparticles (A) and protective colloids (B) for dispersing the metal nanoparticles (A) ,
Before Symbol protective colloid (B) is an organic compound having a carboxyl group and (B1), is constructed out with polymer dispersing agent (B2),
The organic compound (B1) is at least one selected from the group consisting of C _1-3 aliphatic monocarboxylic acids and polycyclic aliphatic hydroxycarboxylic acids, and
The polymer dispersing agent (B2) is a polymer dispersant der Ru inorganic material for bonding agent having a free carboxyl group. The metal constituting the metal nanoparticles (A) is at least a noble metal is a metal containing organic compound (B1) is an inorganic material for bonding agent according to claim 1 which is acetic acid. The ratio of the protective colloid (B) is 1.0 to 60 parts by mass with respect to 100 parts by mass of the metal nanoparticles (A), and the ratio of the organic compound (B1) and the polymer dispersant (B2) is The former / the latter (mass ratio) = 86/14 to 4/96. The bonding agent for inorganic materials according to claim 1 or 2 . Joining of an inorganic material that sinters the inorganic material bonding agent by interposing the inorganic material bonding agent according to any one of claims 1 to 3 between the inorganic material (C1) and the inorganic material (C2). Method. The joining method according to claim 4 , wherein a noble metal, copper or nickel is present on at least one joining surface of the inorganic material (C1) and the inorganic material (C2). The joining method according to claim 5 , wherein the noble metal is gold, silver or palladium. Conjugate obtained inorganic material by any of the methods of claims 4-6.