TWI695389B - Composite microparticles and dispersions, and their manufacturing methods and uses - Google Patents

Abstract

At least a part of the surface of the metal fine particles is coated with a protective layer containing an acid-decomposable polymer to prepare composite fine particles. The resulting composite particles can be sintered at low temperature. The average particle diameter of the aforementioned composite fine particles may be 3000 nm or less. The aforementioned metal particles may be copper particles. The aforementioned acid-decomposable polymer may have an acetal bond. The wiring board can be produced by further adding an acidic compound and/or an acid generator to the dispersion liquid to prepare a conductive ink or a conductive paste, and firing at 200° C. or lower.

Description

Composite microparticles and dispersions, and their manufacturing methods and uses

The present invention relates to composite particles useful in the formation of fine wiring (or wiring patterns), dispersion liquids (or pastes) containing the composite particles, and their manufacturing methods and uses (inks, coating films, fired films, etc.) Wiring boards, electronic devices, etc.).

In the past, in order to obtain a fine metal wiring pattern on an electronic substrate or the like, a method of forming a wiring pattern by using a dispersion liquid containing metal fine particles and printing is studied. In order to produce the metal particles and obtain the dispersion liquid, it is necessary to prevent the oxidation and aggregation of the metal particles. Therefore, there must be a protective agent that coats the metal particles. Among metal particles, copper particles have high electrical conductivity, are inexpensive, and are not likely to cause migration (short circuit caused by metal leakage), and have attracted attention in recent years. However, they have the disadvantages of "easy oxidation and high resistance" . Therefore, in order to prevent the oxidation and aggregation of copper particles, copper particles coated with various protective agents have been proposed.

Japanese Patent No. 4978844 (Patent Document 1) proposes a copper fine particle dispersion liquid comprising copper fine particles with a particle size of 100 nm or less coated with a water-soluble polymer and hydroxycarboxylic acid, and hydroxycarboxylic acid and polyol And/or polar solvents. It is described in this document that after forming the dispersion liquid into a film, it is fired at 250 to 300°C.

Japanese Patent No. 5063003 (Patent Document 2) discloses a method for producing copper nanoparticles, which comprises adding a reducing agent to a solution containing a copper salt of an organic acid and a monoamine having 8 to 16 carbon atoms to make copper The metal core forms and grows. In this document, it is described that the obtained conductive composition containing copper nanoparticles is applied to a substrate and heat-treated at a temperature of 50° C. or higher and less than 500° C. to form a coating layer.

Japanese Patent No. 5227828 (Patent Document 3) discloses a method of producing copper nanoparticles by dissolving a copper source in a solvent containing citric acid, generating copper ions, and adding a reducing agent. In this document, the copper test pieces were joined under heating conditions of 400° C. using the oxidation-resistant copper nanoparticles obtained by the aforementioned method.

However, the copper particles of these documents use high molecular weight compounds or highly polar compounds as protective agents in order to improve the copper's protective ability. Therefore, in the case of forming wiring patterns with such copper particles, in order to eliminate the protective agent, it is necessary to thermally decompose them at a high temperature. If the thermal decomposition temperature is high, the substrate will be limited to hard inorganic materials such as glass or ceramics. Therefore, bases formed from resins with low heat resistance and softness such as polyethylene terephthalate (PET) It becomes difficult to form wiring patterns on the material.

In addition, Japanese Patent No. 5403740 (Patent Document 4) discloses a fired paste composition containing a resin having a non-cyclic acetal structural unit, a powder, and a solvent. In this document, various inorganic particles and organic particles are exemplified for the aforementioned powder. In the examples, glass particles with an average particle diameter of 2 μm, silver powder, carbon nanotubes with a particle diameter of 40 to 70 nm, and crosslinked organic particles are used. Particles, alumina particles with an average particle size of 1 μm, oxidation magnesium. In the examples, the paste composition was heated to 1500°C and sintered.

However, in this document, a resin having an acetal structure is blended into the composition as a binder resin, and the particle size of the metal powder is not described.

[Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent No. 4978844 (Request 1, Paragraph [0039], Examples)

[Patent Document 2] Japanese Patent No. 5063003 (Request 1, Paragraph [0023])

[Patent Document 3] Japanese Patent No. 5227828 (request item 1, example)

[Patent Document 4] Japanese Patent No. 5403740 (Request Item 1, Paragraph [0002] [0003] [0044] [0045], Examples)

Therefore, the object of the present invention is to provide composite particles that can be sintered at a low temperature and a dispersion liquid (or paste) containing the composite particles, as well as their manufacturing methods and uses (ink, coating film, fired film, wiring board, Electronic devices, etc.).

Another object of the present invention is to provide composite particles that can suppress oxidation or aggregation and have excellent stability regardless of whether they contain nano-sized metals or not, as well as composite particles that can be sintered at low temperatures below 200°C The dispersion of fine particles and their manufacturing methods and uses.

Still another object of the present invention is to provide composite fine particles capable of forming high-density conductors such as fine wiring patterns on flexible resin substrates, dispersion liquids containing the composite fine particles, and their production methods and uses.

Another object of the present invention is to provide composite fine particles having excellent solubility in organic solvents, dispersion liquids containing the composite fine particles, and their production methods and uses.

The present inventors have intensively reviewed the results to achieve the above-mentioned problems, and found that by coating the surface of the metal fine particles with an acid-decomposable polymer, they can be sintered at a low temperature, and thus completed the present invention.

That is, the composite fine particles of the present invention include metal fine particles and a protective layer that covers at least a part of the surface of the metal fine particles and includes an acid-decomposable polymer. The average particle diameter of the aforementioned composite fine particles may be 3000 nm or less. The aforementioned metal particles may be copper particles. The aforementioned acid-decomposable polymer may have an acetal bond. The acid-decomposable polymer may be a polymer having a repeating unit represented by the following formula (1), a polymer having a repeating unit represented by the following formula (2), or a repeating unit represented by the following formula (3) Polymer or two types of repeating units represented by the following formulas (4a) and (4b).

(In the formula, R ¹ to R ³ , each of which is the same as or different from each other, represents a hydrogen atom, a halogen atom, a hydroxyl group, a hydroperoxy group, an amine group, a thiol group, a sulfonic acid group, or an organic group, and R ¹ to R ^Three or more of ³ may be bonded to each other to form a ring; R ⁴ represents a halogen atom, a hydroxyl group, a hydroperoxy group, an amine group, a thiol group, a sulfonic acid group, or an organic group).

(In the formula, ring Z represents a saturated heterocyclic ring which may have a substituent and contains an oxygen atom as a hetero atom, and ring Z may be the same saturated heterocyclic ring or a combination of different saturated heterocyclic rings).

[In the formula, A ¹ represents a hydrocarbon group which may have a substituent, or -A ² -(OA ³ ) _n -group (where A ² and A ³ are each the same or different from each other, and represent a hydrocarbon group which may have a substituent ), n is an integer of 1 or more].

[In the formula, A ⁴ represents a hydrocarbon group which may have a substituent, or -A ⁶ -(OA ⁷ ) _m -group (where A ⁶ and A ⁷ , each of which is the same as or different from each other, represents a hydrocarbon group which may have a substituent , M is an integer of 1 or more); A ⁵ represents a hydrocarbon group which may have a substituent, or -A ⁸ -(OA ⁹ ) _k -group (where A ⁸ and A ⁹ , each of which is the same as or different from each other, means (A hydrocarbon group having a substituent, k is an integer of 1 or more); A ⁴ and A ⁵ are different groups].

The present invention also includes the method for producing the composite fine particles, which includes a coating step of covering at least a part of the surface of the metal fine particles with an acid-decomposable polymer. In the aforementioned coating step, at least one raw metal compound selected from the group consisting of metal oxides, metal salts, and metal halides can be reduced in the presence of an acid-decomposable polymer. The aforementioned raw metal compound may be at least one selected from the group consisting of copper oxide, copper sulfate, copper formate, copper acetate, and copper chloride. In the aforementioned coating step, hydrazine can be used as a reducing agent.

In the present invention, a dispersion liquid may also be included, which contains the aforementioned composite fine particles and a dispersion medium. The aforementioned dispersion medium may be an organic solvent. The dispersion liquid of the present invention may further contain an acidic compound and/or an acid generator. The dispersion of the present invention may further contain a reducing agent. The dispersion of the present invention may be conductive ink or conductive paste.

The present invention also includes the aforementioned method for producing a dispersion liquid, which includes a dispersion step of performing a dispersion process under pressure.

In the present invention, a method for manufacturing a coating film is also included, which includes a coating step of coating the dispersion on the substrate.

The present invention also includes a method for producing a fired film, which includes a firing step of heating the aforementioned coating film and firing. In this method, the firing temperature may be 200°C or lower, and firing may be performed in an inert gas environment. The resistivity of the obtained fired film may be 0.5 Ω/□ or less. In the present invention In addition, the method of using this fired film as a wiring board may also be included.

In the present invention, the surface of the metal fine particles is excellent in protection ability, and is coated with an acid-decomposable polymer that can be easily removed, so it can be sintered at a low temperature. In addition, whether it contains nano-sized metal or not, it can suppress oxidation or aggregation and has excellent stability, and at the same time, it can be sintered at a low temperature below 200°C. In addition, since the metal fine particles have a nanometer size, a high-concentration dispersion liquid (ink or paste) can also be prepared, so that a high-density conductor such as a fine wiring pattern can be formed on a flexible resin substrate. Furthermore, it is excellent in solubility in organic solvents, and particularly includes acid-decomposable polymers having a repeating unit represented by the aforementioned formula (3) or two repeating units represented by the aforementioned formulas (4a) and (4b) The composite particles can be dissolved in various organic solvents.

[Figure 1] Figure 1 is a ¹ H-NMR spectrum chart of the polymer obtained in Polymer Synthesis Example 1 of the examples.

[Figure 2] Figure 2 is a ¹ H-NMR spectrum chart of the polymer obtained in Polymer Synthesis Example 2 of the Examples.

[Figure 3] Figure 3 is a ¹ H-NMR spectrum chart of the polymer obtained in Polymer Synthesis Example 3 of the Examples.

[Figure 4] Figure 4 is the measurement results of TG-DTA of the polymer obtained in Polymer Synthesis Example 3 of the Examples.

[Figure 5] Figure 5 is a scanning electron microscope (SEM) photograph (50,000 times) of the composite particles obtained in the composite particle synthesis example 1 of the example.

[Fig. 6] Fig. 6 is obtained by the composite particle synthesis example 2 of the example Scanning electron microscope (SEM) photograph of the composite particles (50,000 times).

[Fig. 7] Fig. 7 is a scanning electron microscope (SEM) photograph (25,000 times) of the composite particles obtained in the composite particle synthesis example 3 of the example.

[Figure 8] Figure 8 is an X-ray diffraction diagram of the composite particles obtained in the composite particle synthesis example 3 of the embodiment.

[Figure 9] Figure 9 is an X-ray diffraction diagram of the coating film and the fired film obtained in Example 1.

[Figure 10] Figure 10 is an X-ray diffraction diagram of the coating film and the fired film obtained in Example 2.

[Figure 11] Figure 11 is an X-ray diffraction diagram of the coating film and the fired film obtained in Example 3.

[Forms for carrying out the invention]

The composite particles of the present invention include metal particles and a protective layer covering at least a part of the surface of the metal particles.

[Metal particles]

Examples of metals constituting the metal particles include transition metals (eg, Group 4A metals of the periodic table such as titanium and zirconium; Group 5A metals of the periodic table such as vanadium and niobium; Group 6A metals of the periodic table such as molybdenum and tungsten ; Group 7A metals of the periodic table such as manganese; Group 8 metals of the periodic table such as iron, nickel, cobalt, ruthenium, rhodium, palladium, rhenium, iridium, platinum; Group 1B metals of the periodic table such as copper, silver, gold, etc.), Group 2B metals of the periodic table (eg, zinc, cadmium, etc.), Group 3B metals of the periodic table (eg, aluminum, gallium, indium, etc.), Group 4B metals of the periodic table (eg, germanium, tin, lead, etc.), periodic Table Group 5B metals (for example, antimony, bismuth, etc.), etc. The metal particles may be particles formed from these alloys, or a plurality of types Combination of metal particles.

Among these metal particles, from the viewpoint of excellent conductivity, particles formed of Group 1B metals of the periodic table, such as copper, silver, and gold, are preferred, since migration is unlikely to occur, and the economy is also excellent. From a viewpoint, copper particles are particularly preferred.

The shape of the metal fine particles is not particularly limited, and examples thereof include a spherical shape, an ellipsoid shape, a polygonal shape (polygonal hammer shape, cube shape, cuboid shape, etc.), a plate shape, a rod shape, and an indefinite shape. Among them, from the viewpoint of excellent dispersibility and the like, a substantially spherical shape or the like is preferred.

The metal fine particles may have an average particle diameter (number average primary particle diameter) of 3000 nm or less. In particular, the average particle size of the metal fine particles is preferably a nano size, for example, about 1 to 1000 nm, more preferably about 10 to 500 nm (for example, 20 to 400 nm), and even more preferably about 30 to 300 nm (particularly 50 ~200nm). If the particle diameter of the metal fine particles is too large, the firing temperature for sintering thereof becomes high, and it may become difficult to form fine wiring patterns. On the other hand, if it is too small, in addition to the difficulty in preparation, the increase in specific surface area may make it easy to oxidize, and it also becomes difficult to redisperse in paste or ink. Furthermore, it may become difficult to improve the conductivity by their combined factors.

In the present invention, the average particle diameter of the metal fine particles can be measured by a method such as image analysis using a scanning electron microscope (SEM).

[The protective layer]

The protective layer contains an acid-decomposable polymer, which has the property of being easily decomposed by acid. The acid-decomposable polymer can also be borrowed in the absence of acid Decomposition by heat at a predetermined temperature, but in the presence of acid can improve the decomposition. The acid-decomposable polymer having such characteristics may be any polymer that can reduce the firing temperature of the sintered metal fine particles, and examples thereof include ester bonds, carbonate bonds, urethane bonds, and acetals. Polymers such as bonds. Among these polymers, a polymer having an acetal bond is preferable from the viewpoint of excellent acid decomposability. In particular, if the repeating unit constituting the main chain of the polymer has an acetal bond (acetal structure), it can be easily decomposed by reacting with an acid. This acetal structure is stable to general stimuli other than acids such as heat, light, and reducing agents (conditions in particle synthesis conditions), so the polymer forming the protective layer has high stability in the absence of acid . The acid-decomposable polymer having an acetal bond may be a polymer having a repeating unit represented by the aforementioned formula (1) [Polymer (1)], or a polymer having a repeating unit represented by the aforementioned Formula (2) [polymerization (2)], a polymer having a repeating unit represented by the aforementioned formula (3) [Polymer (3)], or a polymer having two repeating units represented by the aforementioned formulas (4a) and (4b) [ Polymer (4)].

(Polymer (1))

In R ¹ to R ⁴ of the aforementioned formula (1), examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

The organic group in R ¹ to R ⁴ is not particularly limited as long as it contains a carbon atom, and examples include hydrocarbon groups, alkoxy groups, alkenyloxy groups, aryloxy groups, and aromatic groups that may have substituents. Alkoxy, acyl, acyloxy, alkylthio, alkenylthio, arylthio, aralkylthio, carboxyl, alkoxycarbonyl, aryloxycarbonyl, aralkyloxycarbonyl, epoxy, epoxy-containing Group, oxetanyl group, oxetanyl group-containing group, cyano group, isocyanate group, amine group, isothiocyanate group, substituted amine group, etc.

Examples of the hydrocarbon group include aliphatic hydrocarbon groups, alicyclic hydrocarbon groups, aromatic hydrocarbon groups, groups in which two or more of them are bonded, and the like.

Examples of aliphatic hydrocarbon groups include alkyl groups, alkenyl groups, and alkynyl groups. Examples of alkyl groups include C _1-20 alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, hexyl, octyl, isooctyl, decyl, and dodecyl. It is preferably C _1-10 alkyl, more preferably C _1-4 alkyl) and the like. Examples of alkenyl groups include C _2-20 alkenyl groups such as vinyl, allyl, methallyl, 1-propenyl, isopropenyl, butenyl, pentenyl, and hexenyl. (Preferably C _2-10 alkenyl, more preferably C _2-4 alkenyl) and the like. Examples of the alkynyl group include C _2-20 alkynyl groups (preferably C _2-10 alkynyl groups, more preferably C _2-4 alkynyl groups) such as ethynyl groups and propynyl groups.

Examples of the alicyclic hydrocarbon group include C _3-12 cycloalkyl groups (especially C _5-8 cycloalkyl groups) such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and cyclododecyl groups. ; C _3-12 cycloalkenyl such as cyclohexenyl; C _4-15 crosslinked cyclic hydrocarbon groups such as bicycloheptyl, bicycloheptenyl, etc.

Examples of the aromatic hydrocarbon group include C _6-14 aryl groups (especially C _6-10 aryl groups) such as phenyl and naphthyl.

In addition, the hydrocarbon group includes, for example, a group in which an aliphatic hydrocarbon group such as cyclohexylmethyl and methylcyclohexyl is bonded to an alicyclic hydrocarbon group; a C _{7-18 arane} such as benzyl and phenethyl Group (especially C _7-10 aralkyl group); C _6-10 aryl-C _2-6 alkenyl group such as cinnamyl group; aryl group substituted with C _1-4 alkyl group such as tolyl group, etc. _2-4 Alkenyl substituted aryl groups and other aliphatic hydrocarbon groups are bonded to aromatic hydrocarbon groups and the like.

Examples of alkoxy groups include C _1-10 alkoxy groups such as methoxy, ethoxy, propoxy, isopropoxy, butoxy, and isobutoxy groups (preferably C _{1 -6} alkoxy, more preferably C _1-4 alkoxy) and the like. Examples of alkenyloxy groups include C _2-10 alkenyloxy groups such as allyloxy groups (preferably C _2-6 alkenyloxy groups, and more preferably C _2-4 alkenyloxy groups). Examples of the aryloxy group include C _6-20 aryloxy groups (particularly C _6-14 aryloxy groups) such as phenoxy, tolyloxy, and naphthoxy. Furthermore, the aryloxy group may have a substituent such as C _1-4 alkyl group, C _2-4 alkenyl group, halogen atom, and C _1-4 alkoxy group on the aromatic ring. Examples of aralkoxy groups include C _6-20 aralkoxy groups (especially C _7-18 aralkoxy groups) such as benzyloxy and phenethoxy groups.

Examples of the acyl group include C _1-20 acyl group (especially C _1-12 acyl group) such as ethyl acyl group, propionyl group, (meth)acryl acyl group, and benzyl acyl group. As for the acyloxy group, for example, C _1-20 acyloxy (especially C _1-12 acyloxy) such as acetoxy, propoxy, (meth)acryloyloxy, benzyloxy, etc. Base) etc.

Examples of the alkylthio group include C _1-6 alkylthio groups (especially C _1-4 alkylthio groups) such as methylthio and ethylthio. Examples of the alkenylthio group include C _2-6 alkenylthio groups (especially C _2-4 alkenylthio groups) such as allylthio groups. Examples of the arylthio group include C _6-20 arylthio groups (especially C _6-14 arylthio groups) such as phenylthio, tolylthio, and naphthylthio. Furthermore, the arylthio group may have substituents such as C _1-4 alkyl group, C _2-4 alkenyl group, halogen atom, and C _1-4 alkoxy group on the aromatic ring. Examples of the aralkylthio group include C _6-20 aralkylthio groups (especially C _7-18 aralkylthio groups) such as benzylthio and phenethylthio.

Examples of alkoxycarbonyl groups include C _1-10 alkoxycarbonyl groups (especially C _1-6 alkoxy-carbonyl groups) such as methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, and butoxycarbonyl. )Wait. Examples of the aryloxycarbonyl group include C _6-20 aryloxy-carbonyl groups (particularly C _6-14 aryloxy-carbonyl groups) such as phenoxycarbonyl group, tolyloxycarbonyl group, and naphthoxycarbonyl group. Examples of the aralkyloxycarbonyl group include C _6-20 aralkoxy-carbonyl groups (particularly C _7-18 aralkoxy-carbonyl groups) such as benzyloxycarbonyl.

Examples of the epoxy group-containing group include glycidyl group and glycidyloxy group. Examples of the oxetanyl group-containing group include C _1-10 alkyl-oxetanyloxy groups such as ethyl oxetanyloxy group.

Examples of substituted amine groups include mono- or di-alkyl amine groups (especially mono- or di-C _1- groups such as methyl amine group, ethyl amine group, dimethyl amine group, and diethyl amine group). ₆ alkylamino groups), acetylamino groups, propylamino groups, benzylamino groups, etc. (especially C _1-11 acylamino groups) and the like.

The organic group (especially a hydrocarbon group) may have a substituent, and the substituent may include the aforementioned groups, for example, a halogen atom (for example, fluorine, etc.), a pendant oxygen group, a hydroxyl group, a hydroperoxy group, a carbonyl group, a carboxyl group , Alkoxy, alkenyloxy, aryloxy, aralkoxy, acetyl, acetyl, thiol, alkylthio, alkenylthio, aralkylthio, alkoxycarbonyl, aryloxycarbonyl, Aralkyloxycarbonyl group, epoxy group, epoxy group-containing group, oxetanyl group, oxetanyl group-containing group, cyano group, isocyanate group, carbamoyl group, isothiocyanate group, etc. . The substituent may be a group in which two or more substituents are bonded through C _1-6 alkylene.

In formula (1), although R ¹ to R ³ may be bonded to each other to form a ring, it is usually a monovalent group. R ¹ and R ² are preferably linear or branched C _1-6 alkyl groups, and particularly preferably C _1-3 alkyl groups (especially methyl groups) such as methyl groups. As for R ³ , a hydrogen atom, a linear or branched C _1-6 alkyl group is preferred, and a hydrogen atom is particularly preferred. On the other hand, R ^{4 is} an exemplified monovalent group, preferably a linear or branched C _1-6 alkyl group, and a C _1-3 alkyl group (especially a methyl group) such as a methyl group as a special group good.

Polymer (1) [Polymer (1) having a repeating unit represented by formula (1)] can be used to form the monomer of the repeating unit represented by formula (1), that is, a compound containing an ethylene oxide compound The monomer is obtained by cationic polymerization. The structure of the polymer (1) is not particularly limited, and may be any structure such as a linear chain, a branched chain, or a star.

The polymer (1) may be a homopolymer or a copolymer. The copolymer may be a copolymer obtained by combining the repeating units represented by formula (1) in plural (two or more), or may be a repeating unit represented by formula (1) and other copolymerizable monomers (Monomers with other cationic polymerizability) Copolymers of repeating units formed. Furthermore, the copolymer may be a random copolymer or a block copolymer.

Examples of other copolymerizable monomers include vinyl ether compounds, cyclic ether compounds, benzaldehyde compounds, α-olefin compounds, chain conjugated diene compounds, and olefins having a ring structure of five or more members. Hydrocarbons, cyclopentadiene compounds, cyclic olefin compounds, cyclic conjugated diene compounds, heterocyclic-containing vinyl compounds, silane compounds having ethylenic unsaturated bonds, lactone compounds, etc. These monomers can be used alone or in combination of two or more. Specifically, these other copolymerizable monomers may be, for example, other copolymerizable monomers described in Japanese Patent Laid-Open No. 2013-237755.

In the polymer (1), the ratio of the repeating unit represented by the formula (1) may be 50 mol% or more (eg, 70 to 100 mol%), for example, 80 mol Ear% or more (for example, 80-100 mole %), preferably 90 mole% or more (eg, 90-100 mole %), more preferably 95 mole% or more (especially 99 mole% or more). If the ratio of the repeating unit (1) is too small, it is feared that the treatment of the residue after decomposition of the polymer by acid will become complicated.

The terminal structure of the polymer (1) is not particularly limited, and examples include a terminal structure composed of atomic groups derived from a starting material of cationic polymerization reaction (for example, halogenated hydride of vinyl ether, etc.), and a termination structure derived from polymerization The terminal structure constituted by the atomic group of the agent. In addition, the terminal group of the polymer (1) may be a hydroxyl group formed by impurities in the system, a transfer reaction, or the like when the polymerization reaction starts from a proton.

The number average molecular weight (Mn) of the polymer (1) can be, for example, measured by GPC (gel permeation chromatography), converted to polystyrene, and is about 2000 or more, for example, about 2000 to 100,000, preferably It is about 2,500 to 50,000, more preferably about 3,000 to 15,000. If the number-average molecular weight is too small, there is a fear that the protection capacity for metal fine particles is reduced, or the heat resistance or mechanical strength of the polymer before decomposition becomes insufficient. On the other hand, if it is too large, the productivity of the polymer may decrease, or the solubility may be insufficient, making handling difficult.

The molecular weight distribution [weight average molecular weight (Mw)/number average molecular weight (Mn)] of the polymer (1) is, for example, about 1.3 or less (for example, 1.0 to 1.3), preferably about 1.25 or less (for example, 1.02 to 1.25), more preferably It is about 1.2 or less (for example, 1.05 to 1.20). If the molecular weight distribution is too large, the particle size distribution of the composite fine particles may become large, or the heat resistance or mechanical strength of the polymer before decomposition may become insufficient. In addition, the molecular weight distribution of the polymer can also be calculated by polystyrene conversion by, for example, the GPC method.

The polymer (1) can be produced in accordance with conventional cationic polymerization, for example, it can be produced in accordance with the production method described in Japanese Patent Laid-Open No. 2013-237755.

(Polymer (2))

In the aforementioned formula (2), the ring Z may be a saturated heterocyclic ring containing an oxygen atom as a hetero atom. The saturated heterocyclic ring may be a saturated monocyclic heterocyclic ring (heteromonocyclic ring) or a saturated condensed heterocyclic ring.

Examples of saturated heteromonocycles include oxetane, tetrahydrofuran (oxetane), tetrahydropiperan (oxetane), oxepane, and oxetane Wait. Among them, tetrahydrofuran and tetrahydropiperan (especially tetrahydrofuran) are preferred.

The condensation number of the saturated condensed heterocyclic ring (the number of condensed rings) may be 2 or more ring types, or 3 or more ring types (for example, 3 to 4 ring types), but usually 2 ring types. The number of members of the saturated condensed heterocyclic ring (the total number of members of the condensed ring) is, for example, about 6 to 20 member rings, preferably about 7 to 15 member rings, and more preferably about 8 to 12 member rings (especially 8 to 10 member rings) ring). The number of oxygen atoms contained in the saturated condensed heterocyclic ring may be more than 2, for example, about 2 to 6, preferably about 2 to 4, more preferably about 2 to 3. Two or more oxygen atoms may be included in the same ring, but usually each ring contains more than one (for example, 1-2, particularly preferably one).

The basic skeleton of the saturated condensed heterocyclic ring (the structure of each ring constituting the condensed ring) includes the aforementioned saturated heteromonocyclic ring and the like. Among the aforementioned saturated heteromonocyclic rings, tetrahydrofuran and tetrahydropiperan (especially tetrahydrofuran) are preferred. The condensed ring is formed by combining these rings, which can be a combination of the same ring or a combination of different rings.

Among these saturated heterocycles, a saturated condensed heterocycle is preferred as ring Z from the viewpoint of adhesion.

Examples of the substituent contained in the ring Z include the organic group exemplified in the aforementioned formula (1), the substituent of the organic group represented in the aforementioned formula (1), and the like.

Such a repeating unit (2) may be a repeating unit represented by the following formula (2a).

(In the formula, R ⁵ to R ¹² represent a hydrogen atom or a substituent).

In the aforementioned formula (2a), R ⁵ to R ¹² may be a single group selected from such substituents and hydrogen atoms, or a combination of two or more types. For R ⁵ to R ¹² , from the viewpoints of ease of production and ease of obtaining raw materials, C _1-4 alkyl groups such as a hydrogen atom and a methyl group are preferred, and a hydrogen atom is particularly preferred.

The polymer (2) [the polymer (2) having a repeating unit represented by the formula (2)] can be obtained by a divinyl ether having an oxygen-containing saturated heterocyclic skeleton and a diol having an oxygen-containing saturated heterocyclic skeleton The reaction, or the polymerization of hydroxyvinyl ether having an oxygen-containing saturated heterocyclic skeleton is obtained. The structure of the polymer (2) is not particularly limited, and may be any structure such as a linear type, a branched type, or a star shape.

The polymer (2) may be a homopolymer or a copolymer. The copolymer may be a repeating unit represented by the aforementioned formula (2), and the ring Z system phase Copolymers of heterosaturated heterocyclic ring combinations, for example, heterosaturated heteromonocyclic rings, heterosaturated condensed heterocyclic rings, saturated heteromonocyclic rings and saturated condensed heterocyclic rings. That is, in the aforementioned formula (2), the ring Z may be the same saturated heterocyclic ring or a combination of different saturated heterocyclic rings. Furthermore, the copolymer may be a copolymer of a unit formed by the repeating unit represented by the aforementioned formula (2) and other copolymerizable monomers (other divinyl ether and/or other glycol). Furthermore, the copolymer may be a random copolymer or a block copolymer.

In the polymer (2), the ratio of the repeating unit represented by the aforementioned formula (2) may be 50 mol% or more (eg, 70-100 mol%), such as 80 mol% or more (eg, 80-100 mol) %), preferably 90 mol% or more (for example, 90 to 100 mol%), more preferably 95 mol% or more (especially 99 mol% or more). If the ratio of the repeating unit (2) is too small, there is a fear that the treatment of the residue after the polymer is decomposed by acid will become complicated.

The terminal group of the polymer (2) is either a vinyl ether group or a hydroxyl group, and it may be either a single type or a combination of two types. In this way, since the polymer of the present invention has a hydroxyl group and/or vinyl group at the terminal, the adhesion to the base material formed of an inorganic material or the like can be imparted by the hydroxyl group, or can be obtained by polymerizing the vinyl group and other polymerizable groups Resin with acid-decomposable cross-linked structure.

The weight average molecular weight (Mw) of the polymer (2), when measured by, for example, the GPC method, in polystyrene conversion, may be about 1,000 or more, such as about 1,000 to 100,000, preferably about 2,000 to 50,000, more preferably It is about 3000~30,000 (especially 4000~10000). The polymer (2) has a high molecular weight despite having an oxygen-containing saturated heterocycle. If the weight average molecular weight is too small , The protection ability of the metal particles may decrease, or the heat resistance or mechanical strength of the polymer before decomposition may become insufficient. On the other hand, if it is too large, the polymer productivity may be reduced, or the solubility may be insufficient, and the operation will become difficult.

The molecular weight distribution (Mw/Mn) of the polymer (2) may be, for example, about 1 to 5, preferably about 1.1 to 3, and more preferably about 1.2 to 2.8 (especially 1.5 to 2.5). If the molecular weight distribution is too large, the particle size distribution of the composite fine particles may be large, or the heat resistance or mechanical strength of the polymer before decomposition may become insufficient. In addition, the molecular weight distribution of the polymer can also be calculated in terms of polystyrene by the GPC method, for example.

The polymer (2) is a production method including a reaction step of reacting a divinyl ether represented by the following formula (5) with a diol represented by the following formula (6), or includes the following A polymer obtained by a method for producing a reaction step of polymerizing a hydroxyvinyl ether represented by formula (7).

(In the formula, ring Z represents a saturated heterocyclic ring which may have a substituent and contains an oxygen atom as a hetero atom, and ring Z may be the same saturated heterocyclic ring as described above, or may be a combination of different saturated heterocyclic rings) .

In the reaction step, as for the divinyl ether (5), it may be a divinyl ether having the ring Z exemplified in the foregoing repeating unit (2) as a basic skeleton, which is represented by the following formula (5a). Vinyl ether (especially divinyl ether having a substituent exemplified in the aforementioned repeating unit (2a)) is preferred . As for the diol (6), it may be a diol having the ring Z exemplified in the aforementioned repeating unit (2) as a basic skeleton, and the diol represented by the following formula (6a) (especially having the aforementioned The diol of the substituent exemplified in the repeating unit (2a) is preferred. As for the hydroxyvinyl ether (7), it may be a hydroxyvinyl ether having the ring Z exemplified in the aforementioned repeating unit (2) as a basic skeleton, and the hydroxyvinyl ether represented by the following formula (7a) (especially It is preferably a hydroxyvinyl ether having a substituent exemplified in the aforementioned repeating unit (2a).

(In the formula, R ⁵ to R ¹² represent a hydrogen atom or a substituent).

烷二甲醇二乙烯基醚等)、其他二元醇(例如，乙二醇、丙二醇、四亞甲基二醇、二乙二醇、三乙二醇、環己烷二甲醇、雙酚A等)、其他羥基乙烯基醚(例如，羥基丁基乙烯基醚、羥基環己基乙烯基醚、二乙二醇單乙烯基醚、三乙二醇單乙烯基醚、2,2-降

烷二甲醇單乙烯基醚等)等。 In the reaction step, in addition to divinyl ether (5) and glycol (6), or hydroxyvinyl ether (7), a copolymerizable monomer may be added. Examples of the copolymerizable monomers include other divinyl ethers (for example, butyl divinyl ether, cyclohexane divinyl ether, diethylene glycol divinyl ether, and triethylene glycol divinyl ether. Ether, 2,2-drop

Alkane dimethanol divinyl ether, etc.), other glycols (for example, ethylene glycol, propylene glycol, tetramethylene glycol, diethylene glycol, triethylene glycol, cyclohexane dimethanol, bisphenol A, etc. ), other hydroxyvinyl ethers (for example, hydroxybutyl vinyl ether, hydroxycyclohexyl vinyl ether, diethylene glycol monovinyl ether, triethylene glycol monovinyl ether, 2,2-decane

Alkane dimethanol monovinyl ether, etc.).

Among them, the alternating polymer of divinyl ether (5) and glycol (6) is preferred.

The ratio (mole ratio) of divinyl ether (5) to diol (6) can be selected from the former/the latter = about 10/1 to 1/10, but from the viewpoint of polymerizability, For example, about 2/1~1/2, preferably about 1.5/1~1/1.5, more preferably about 1.2/1~1/1.2 (especially 1.1/1~1/1.1), usually about Moore.

The reaction can be carried out in the presence of a catalyst. As for the catalyst, a conventional catalyst can be used, but from the viewpoint of high reaction promotion, an acid catalyst is preferable. As for the acid catalyst, it may be strong acid such as hydrochloric acid, sulfuric acid, p-toluenesulfonic acid, etc. However, from the viewpoint of keeping the stability of the polymer produced, acetic acid, phosphoric acid, aromatic sulfonic acid (e.g. toluene Sulfonic acids, etc.) and weak acids such as salts with bases (e.g., weak bases such as pyridine, etc.) are preferred, and from the viewpoint of excellent balance of stability and reactivity of the polymer, toluene such as pyridinium p-toluenesulfonate Sulfonates are preferred.

The ratio of the catalyst is, for example, about 0.1 to 20 moles relative to the total moles of 100 moles of polymerized components (for example, the total moles of divinyl ether (5) and glycol (6)). It is preferably about 0.3 to 15 moles, and more preferably about 0.5 to 10 moles (especially 1 to 5 moles). If the ratio of the catalyst is too small, the reactivity will decrease, and if it is too large, the physical properties of the polymer may be adversely affected.

The reaction can be carried out in a solvent. The solvent is not particularly limited as long as it is a non-reactive solvent for the aforementioned divinyl ether and glycol, and examples include hydrocarbons (toluene, xylene, etc.) ), halogen solvents (dichloromethane, chloroform, etc.), ethers (dialkyl ethers such as diethyl ether, cyclic ethers such as tetrahydrofuran, etc.), ketones (acetone, methyl ethyl ketone, etc.), esters (Methyl acetate, ethyl acetate, butyl acetate, etc.), Cylosulfoacetate (Ethyl cylosulfoacetate and other C _1-4 alkyl cylosulfoacetate, propylene glycol monomethyl ether ether Propylene glycol mono C _1-4 alkyl ether acetate, etc.) etc. These solvents can be used alone or in combination of two or more. Among these solvents, cellulose acetate (for example, propylene glycol mono C _1-4 alkyl ether acetate such as propylene glycol monomethyl ether acetate) is widely used.

The amount of the solvent used is, for example, about 10 to 1000 parts by weight, preferably about 100 parts by weight of the total amount of the polymerization component (for example, the total amount of divinyl ether (3) and glycol (4)). 50 to 500 parts by weight, more preferably about 100 to 300 parts by weight (especially 150 to 200 parts by weight).

The reaction system can be carried out by adding conventional additives such as a polymerization accelerator and a polymerization inhibitor. Furthermore, the reaction system may contain moisture, or the reaction may be carried out in the presence of unavoidable moisture from raw materials.

In the reaction step, the reaction may proceed without excessive heating or cooling. The reaction temperature may be, for example, about 0 to 60°C, preferably about 10 to 50°C, and more preferably about 20 to 45°C (especially 30 to 40 ℃).

The reaction time may be, for example, about 30 minutes to 48 hours, usually about 1 to 36 hours, preferably about 2 to 24 hours. Furthermore, the reaction can be carried out under an inert environment (eg, nitrogen, helium, argon, etc.).

The polymer obtained after the reaction step can be further provided in the separation and purification step. In the separation and purification step, separation and purification can be performed by conventional separation and purification treatments such as filtration, concentration, reprecipitation, extraction, crystallization (recrystallization, etc.). Furthermore, in the case where an acid catalyst is used, it can be neutralized with alkali in accordance with conventional methods.

(Polymers (3) and (4))

In the aforementioned formulas (3), (4a) and (4b), examples of the hydrocarbon group of A ¹ to A ⁹ (A ¹ to A ⁹ skeleton) include, for example, aliphatic hydrocarbon groups, alicyclic hydrocarbon groups, and aromatic hydrocarbon groups , These two or more kinds of bonding base.

Examples of the aliphatic hydrocarbon group include alkylene groups, alkenyl groups, and alkynyl groups. Examples of alkylene groups include methylene, ethylidene, propylidene, trimethylene, butylidene, tetramethylene, hexamethylene, isohexylidene, octamethylene, C _1-20 alkylene such as iso-octyl, decamethylene, dodecamethylene, etc. Examples of the alkenyl group include vinylidene, vinylidene, methylallyl, 1-propenyl, isopropenyl, butenyl, pentenyl, and hexenyl. Alkenyl and other C _2-20 alkenyl and so on. Examples of the alkynyl group include C _2-20 alkynyl group such as ethynyl group and propynyl group.

Examples of the alicyclic hydrocarbon group include C _3-12 cycloalkyl groups (especially C), such as cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, and cyclododeca-diyl group. _5-8 cycloalkyl); C _3-12 cycloalkenyl such as cyclohexenyl; C _4-15 cross-linked cyclic hydrocarbon such as bicycloheptyl and bicycloheptenyl; etc.

Examples of the aromatic hydrocarbon group include C _6-14 arylidene groups such as phenylene and naphthyl.

In addition, the hydrocarbon group may be, for example, a group obtained by bonding two or more kinds selected from an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group. Examples of the group formed by bonding an aliphatic hydrocarbon group and an alicyclic hydrocarbon group include: cyclohexyl methylene, methyl cyclohexyl, dicyclohexyl methane-4,4′-diyl, di Cyclohexylpropane-4,4'-diyl, etc. Examples of the group formed by bonding an aliphatic hydrocarbon group and an aromatic hydrocarbon group include: tolyl, xylyl, diphenylmethane-4,4'-diyl, and diphenylpropane-4, 4'-diyl and so on.

Examples of the substituents of these hydrocarbon groups include the substituents of the organic group exemplified in the aforementioned formula (1).

In formulas (3), (4a), and (4b), n, m, and k are integers of 1 or more, preferably about 1-10, more preferably about 1-5 (especially 1-3).

Among these groups, as far as A ¹ to A ⁹ are concerned, an alkylene group having a carbon number of 3 or more (for example, C _3-10 alkylene group) is preferred, and a tri-octa methylene group (especially three to Hexamethylene) is particularly preferred.

Furthermore, in the present invention, in the formulae (3), (4a) and (4b), the A ¹ , A ⁴ and A ⁵ skeletons do not contain saturated heterocycles containing oxygen atoms as heteroatoms.

Polymers (3) and (4) can be reacted with divinyl ether having A ¹ skeleton and diol having A ¹ skeleton, divinyl ether having A ⁴ or A ⁵ skeleton and having A ⁵ It can be obtained by the reaction of the diol of the A ⁴ skeleton or the polymerization of the hydroxy vinyl ether having the A ¹ skeleton. The structure of the polymers (3) and (4) is not particularly limited, and may be any structure such as a linear chain, a branched chain, or a star.

The polymer (3) may be a homopolymer, or may be a copolymer of units formed with other copolymerizable monomers (units formed with monomers other than monomers that can form repeating units (3)). The copolymer may be a random copolymer or a block copolymer.

The polymer (4) is a copolymer containing repeating units (4a) and (4b), but like the polymer (3), it can be a unit formed by further containing other copolymerizable monomers (repeating units can be formed) (4a) and (4b) monomers other than monomers) copolymers. The copolymer may be a random copolymer or a block copolymer.

In the present invention, the other copolymerizable monomers in the polymers (3) and (4) also do not contain saturated heterocycles containing oxygen atoms as heteroatoms.

In the polymers (3) and (4), the ratio of the repeating units represented by formula (3) or the two types of repeating units represented by formulas (4a) and (4b) may be 50 mol% or more ( For example, 70 to 100 mol%), for example, 80 mol% or more (eg, 80 to 100 mol%), preferably 90 mol% or more (eg, 90 to 100 mol%), and more preferably 95 mol% Above (especially more than 99 mol%). If the ratio of the aforementioned repeating units is too small, there is a fear that the treatment of the residue after the acid decomposition of the polymer will become complicated.

Among the polymers (3) and (4), a polymer having a repeating unit represented by the formula (3) (especially a homopolymer) is preferable from the viewpoint that the polymer chain has homogeneous decomposability. In the polymer (3), A ¹ may be three to six methylene, preferably four to pentamethylene, and more preferably tetramethylene.

The terminal groups of the polymers (3) and (4) are either vinyl ether groups or hydroxyl groups, either of which may be alone or a combination of two groups. Accordingly, since the polymers (3) and (4) have hydroxyl groups and/or vinyl groups at the ends, the hydroxyl groups can impart adhesion to substrates formed with inorganic materials, etc., or through vinyl groups and other The polymerizable group is polymerized to obtain a resin having an acid-decomposable cross-linked structure.

The weight average molecular weights (Mw) of the polymers (3) and (4), when measured by the GPC method, in terms of polystyrene, can be more than 1,000, for example, about 1,000 to 100,000, preferably about 2,000 to 50,000 It is more preferably about 3000~30,000 (especially 4000~10000). If the weight-average molecular weight is too small, there is a fear that the protection ability to the metal fine particles is reduced, or the heat resistance or mechanical strength of the polymer before decomposition becomes insufficient. on the other hand, If it is too large, the productivity of the polymer may decrease, the solubility may be insufficient, and operation may become difficult.

The molecular weight distributions (Mw/Mn) of the polymers (3) and (4) are, for example, about 1 to 5, preferably about 1.1 to 3, and more preferably about 1.2 to 2.8 (especially 1.5 to 2.5). If the molecular weight distribution is too large, the heat resistance or mechanical strength of the polymer before decomposition may become insufficient. Furthermore, the molecular weight distribution of the polymer can also be calculated in terms of polystyrene by the GPC method, for example.

The polymers (3) and (4) are as described above, and can be produced by a method including a reaction step of reacting the corresponding divinyl ether with the corresponding diol, or a reaction including polymerizing the corresponding hydroxyvinyl ether The manufacturing method of the steps is obtained.

烷二甲醇二乙烯基醚等。就具有A¹、A⁴或A⁵骨架之二元醇而言，可列舉如：四亞甲基二醇、二乙二醇、三乙二醇、環己烷二甲醇、雙酚A等。就具有A¹、A⁴或A⁵骨架之羥基乙烯基醚而言，可列舉如：羥基丁基乙烯基醚、羥基環己基乙烯基醚、二乙二醇單乙烯基醚、三乙二醇單乙烯基醚、2,2-降

烷二甲醇單乙烯基醚等。 In the reaction step, as for the divinyl ether having A ¹ , A ⁴ or A ⁵ skeleton, for example, it may include: butyl divinyl ether, cyclohexane divinyl ether, diethylene glycol diethylene Ether, triethylene glycol divinyl ether, 2,2-decyl

Alkane dimethanol divinyl ether, etc. Examples of the diol having an A ¹ , A ⁴ or A ⁵ skeleton include tetramethylene glycol, diethylene glycol, triethylene glycol, cyclohexane dimethanol, and bisphenol A. Examples of hydroxyvinyl ethers having an A ¹ , A ⁴ or A ⁵ skeleton include: hydroxybutyl vinyl ether, hydroxycyclohexyl vinyl ether, diethylene glycol monovinyl ether, triethylene glycol Monovinyl ether, 2,2-drop

Alkane dimethanol monovinyl ether, etc.

Among these, alternating polymers of the corresponding divinyl ether and the corresponding diol are preferred. The ratio (molar ratio) of the aforementioned divinyl ether to the aforementioned diol can be selected from the former/the latter=about 10/1 to 1/10 Range, but from the viewpoint of polymerizability, it may be, for example, 2/1 to 1/2, preferably about 1.5/1 to 1/1.5, more preferably about 1.2/1 to 1/1.2 (especially 1.1/ 1~1/1.1), usually about equal molar.

The reaction can be carried out in the presence of a catalyst. As for the catalyst, a conventional catalyst can be used, but from the viewpoint of high reaction promotion, an acid catalyst is preferable. As for the acid catalyst, the acid catalyst used in the manufacturing method of the polymer (2) can be used and used in the same ratio as the manufacturing method of the polymer (2).

The reaction can be carried out in a solvent. As for the solvent, the solvent used in the method for producing the polymer (2) can be used and can be used in the same amount as the method for producing the polymer (2).

Furthermore, the addition of additives, the reaction temperature and time, and the separation and purification steps of the obtained polymer are also the same as the production method of the polymer (2).

(Characteristics of protective layer)

The protective layer may contain an acid-decomposable polymer, and may also contain other components. For example, it may contain conventional additives other than the catalyst, solvent, and reducing agent mixed in the manufacturing step.

The ratio of the reducing agent relative to the total amount of the protective layer is, for example, about 10% by weight or less (for example, 0.001 to 10% by weight), preferably about 5% by weight or less, and more preferably about 1% by weight or less. If the ratio of the reducing agent is too large, there is a fear that the conductivity after firing may decrease.

As for conventional additives, it may include, for example, other polymers (adhesives), stabilizers (antioxidants, ultraviolet absorbers, etc.), metal corrosion inhibitors, surfactants or dispersants, water-soluble polymers, waxes , Dispersing stabilizers, tackifiers or viscosity modifiers, moisturizing agents, shaking imparting agents, leveling agents, defoamers, fillers, etc. The ratio of other components may be, for example, 50% by weight or less relative to the total amount of the protective layer, for example, about 0.01 to 10% by weight (particularly 0.1 to 5% by weight).

The protective layer can cover at least a part of the surface of the metal particles, and the coverage rate of the surface of the metal particles can be more than 10%, for example more than 30%, preferably more than 50%, more preferably more than 80% (especially 90% (Above), the entire surface of the metal particles can also be coated. If the coverage rate of the protective layer is too low, the metal particles may be easily oxidized or aggregated, and the stability of the metal particles may decrease.

[Characteristics and manufacturing methods of composite particles]

The composite fine particles of the present invention may have an average particle size (number average primary particle size) of 3000 nm or less. In particular, the average particle size of the composite particles is preferably a nanometer size, for example, about 1 to 1000 nm, more preferably about 10 to 500 nm (for example, 20 to 400 nm), and even more preferably about 30 to 300 nm (in particular, 50 to 200 nm ). If the particle size of the composite particles is too large, the sintering temperature for sintering will become higher, and the formation of fine wiring patterns will also become difficult. On the other hand, if it is too small, in addition to the difficulty in preparation, the increase in specific surface area makes it easy to oxidize, and it also becomes difficult to re-disperse the paste or ink. Furthermore, it is also difficult to improve the electrical conductivity due to these composite properties.

In the present invention, the average particle diameter of the composite fine particles can be measured by measuring arbitrary 100 to 300 particle diameters based on the SEM photograph and then calculating the average value.

The composite particles of the present invention can be acid decomposable by The polymer is obtained by a manufacturing method of a coating step in which at least a part of the surface of metal fine particles is coated.

In the aforementioned coating step, the method of coating the metal fine particles with an acid-decomposable polymer is not particularly limited, and it can generally be used to reduce the raw metal compound in the presence of an acid-decomposable polymer.

Examples of raw metal compounds include metal oxides, metal salts, and metal halides. These raw metal compounds can be used alone or in combination of two or more.

The raw metal compound can be selected according to the type of metal particles. The metal halide may include metal chloride, metal bromide, metal iodide and the like. The metal salt may include metal inorganic acid salts (sulfate, nitrate, carbonate, hydrochloride, phosphate, etc.), metal organic acid salts (formate, acetate, lactate, etc.), and the like. The metal salt may be a hydrate.

In the case of metal particles of copper particles, copper oxide includes copper (I) oxide (cuprous oxide) and copper (II) oxide (copper oxide). Copper halides include copper (I) (cuprous chloride), copper (II) (copper chloride), copper (I) bromide (copper bromide), copper (II) bromide (bromide) Copper) etc. The metal salt includes copper sulfate, copper nitrate, copper formate, copper acetate, and the like. Among them, at least one selected from the group consisting of copper oxide, copper sulfate, copper formate, copper acetate, and copper chloride is preferred.

The ratio of the acid-decomposable polymer during synthesis can be selected from the range of about 1 to 500 parts by weight (particularly 3 to 400 parts by weight) relative to 100 parts by weight of the raw metal compound. In particular, when the acid-decomposable polymer is the polymer (1) or (2), the ratio of the acid-decomposable polymer is, for example, about 5 to 400 parts by weight relative to 100 parts by weight of the raw metal compound. It is preferably about 10 to 250 parts by weight, and more preferably about 15 to 200 parts by weight. In the case where the acid-decomposable polymer is the polymer (3) or (4), the ratio of the acid-decomposable polymer is, for example, about 3 to 30 parts by weight with respect to 100 parts by weight of the raw metal compound, preferably about 5-20 parts by weight, more preferably about 6-10 parts by weight. If the ratio of the acid-decomposable polymer is too small, the stability of the metal fine particles may decrease and coarse particles may be generated. If the ratio is too large, very fine particles may be generated, and composite particles having a desired particle size may not be obtained. The sintering will become difficult.

As for the reducing agent, conventional reducing agents can be exemplified, for example, sodium borohydride, lithium aluminum hydride, hypophosphorous acid or salts thereof, boranes, formalin, hydrazine, amines, alcohols, phenolic hydroxyl groups Carboxylic acid etc. These reducing agents can be used alone or in combination of two or more. Among these reducing agents, sodium boron hydride, hydrazine, tertiary amine, ethylene glycol, tannic acid, etc. can be widely used, with hydrazine being preferred. Hydrazine may be a hydrate.

The ratio of the reducing agent can be selected from the range of about 0.1 to 50 mol (especially 0.2 to 40 mol) relative to 1 mol of the raw metal compound. In particular, when the acid-decomposable polymer is the polymer (1) or (2), the ratio of the reducing agent is, for example, about 0.5 to 30 mol, preferably about 1 to 30 mol, and more preferably about 3 to 10 moles. In the case where the acid-decomposable polymer is the polymer (3) or (4), the ratio of the reducing agent is, for example, about 0.2 to 30 moles, preferably about 0.3 to 10 moles, more preferably about 0.5 to 5 moles ear. If the ratio of the reducing agent is too small, the reduction of metal ions may become insufficient, and if it is too large, the particle size may become small, and composite particles having a desired particle size may not be obtained, which requires time for purification after the reaction.

The reduction reaction using a reducing agent can be normal temperature, but From the viewpoint of promoting the reduction reaction, it may be heated. In the case of heating, the heating temperature may be, for example, about 40 to 80°C, preferably about 45 to 70°C, and more preferably about 50 to 60°C. The reaction time may be, for example, about 10 minutes to 20 hours, usually about 30 minutes to 10 hours, preferably about 1 to 5 hours. The reduction reaction can be carried out with stirring.

烷或四氫呋喃等環狀醚類；二甲基乙醯胺等醯胺類等。此等溶劑可單獨或將二種以上組合而使用。此等溶劑之中，泛用水、四氫呋喃等環狀醚類。溶劑之比率，相對於100重量份之原料金屬化合物，為例如約10~5000重量份，較佳為約30~4000重量份，更佳為約50~3000重量份。 The reduction reaction can be carried out in the presence of a solvent. The solvent can be selected according to the type of the raw metal compound and the reducing agent, and examples include alcohols such as water, ethanol, and isopropanol; ketones such as acetone, and

Cyclic ethers such as alkane or tetrahydrofuran; amides such as dimethylacetamide. These solvents can be used alone or in combination of two or more. Among these solvents, cyclic ethers such as water and tetrahydrofuran are used. The ratio of the solvent is, for example, about 10 to 5000 parts by weight, preferably about 30 to 4000 parts by weight, and more preferably about 50 to 3000 parts by weight with respect to 100 parts by weight of the raw metal compound.

In the reduction reaction, the pH can be adjusted by conventional methods using acids (inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, and organic acids such as acetic acid) and alkalis (inorganic bases such as sodium hydroxide and ammonia).

Although the composite particles obtained in the coating step can be used as they are in the ink as it is after the reduction reaction, the dispersion liquid is usually provided in the separation and purification step. In the separation and purification step, the resulting composite particles can be washed after separation from the solvent by conventional methods (for example, filtration treatment such as centrifugal separation, membrane filter, extra-limit filtration, etc.) And dry and refined.

[Dispersions]

The dispersion liquid of the present invention may include the aforementioned composite fine particles and a dispersion medium, and although it may be the dispersion liquid obtained in the aforementioned coating step, it is generally in accordance with The purpose is obtained by dispersing the composite fine particles obtained through the separation and purification step in a dispersion medium.

The dispersion medium can be selected according to the type of the composite particles, or it can be water. However, from the viewpoint of dispersing the composite particles with a high concentration, an organic solvent is preferred. In the present invention, the composite fine particles (especially composite fine particles coated with a protective layer containing the polymer (3) or (4)) can be dispersed in various organic solvents due to their excellent solvent solubility. If the dispersion liquid can contain composite fine particles in a high concentration, the dispersion liquid can be easily used as a conductive paste or a conductive ink because a dense fired film is easily formed.

烷、四氫呋喃等環狀醚類)、芳香族系溶劑(例如，甲苯、二甲苯等芳香族烴類)、鹵素系溶劑(例如，二氯甲烷、氯仿等鹵烷類)、腈系溶劑(例如，乙腈、苄腈等)、硝基系溶劑(例如，硝基苯等)等。此等分散媒可單獨或將二種以上組合而使用。 Examples of organic solvents include: alcohol-based solvents (for example, alkanols such as methanol, ethanol, isopropanol, and butanol; aliphatic polyhydric alcohols such as ethylene glycol and glycerin; cyclohexanol and terpineol , Alicyclic alcohols such as dihydroterpineol, etc.), ester solvents (for example, acetates such as ethyl acetate, butyl acetate, propylene glycol monomethyl ether monoacetate), ketone solvents (for example, Chain ketones such as acetone; cyclic ketones such as cyclohexanone), ether solvents (for example, chain ethers such as propylene glycol monomethyl ether and diethylene glycol dimethyl ether; two

Cyclic ethers such as alkane and tetrahydrofuran), aromatic solvents (for example, aromatic hydrocarbons such as toluene and xylene), halogen solvents (for example, haloalkanes such as methylene chloride and chloroform), and nitrile solvents (for example , Acetonitrile, benzonitrile, etc.), nitro-based solvents (for example, nitrobenzene, etc.), etc. These dispersion media can be used alone or in combination of two or more.

Among these dispersion media, alcohol solvents, ester solvents, and cyclic ether solvents are commonly used. The dispersion medium can be selected according to the type of the protective layer. When the protective layer contains the polymer (1), the dispersion medium can be C _1-4 alkanol such as methanol, cyclic ether such as tetrahydrofuran, and acetic acid C _1- such as ethyl acetate ₃ alkyl esters, etc. When the protective layer contains the polymer (2), the dispersion medium may be an alicyclic alcohol such as terpineol, a cyclic ether such as tetrahydrofuran, a C _1-3 alkyl acetate such as ethyl acetate, or the like. When the protective layer contains the polymer (3) or (4), the dispersion medium may be C _1-4 alkanols such as methanol, alicyclic alcohols such as terpineol, cyclic ethers such as tetrahydrofuran, and acetic acid C such as ethyl acetate _1-3 alkyl esters.

The ratio of the dispersion medium is, for example, about 10 to 1000 parts by weight, preferably about 30 to 500 parts by weight, and more preferably about 50 to 400 parts by weight (especially 80 to 300 parts by weight) relative to 100 parts by weight of the composite particles. ). If the ratio of the dispersion medium is too large, cracks or the like may easily occur during the drying process after coating, and it becomes difficult to form a sintered film with high conductivity; if it is too small, there is a possibility that the coating properties of the dispersion liquid may be lowered.

Since the dispersion liquid of the present invention improves sintering at a low temperature, the decomposition aid of the acid-decomposable polymer may further contain an acidic compound and/or an acid generator.

The acidic compound includes inorganic acids, organic acids, and the like. Examples of inorganic acids include hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, and boric acid. Examples of organic acids include aliphatic monocarboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, caprylic acid, and stearic acid; oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, and horse Aliphatic dicarboxylic acids such as maleic acid; alicyclic carboxylic acids such as naphthenic acid; hydroxycarboxylic acids such as glycolic acid, lactic acid, tartaric acid, malic acid, citric acid; aromatic hydrocarbon sulfonic acids such as toluenesulfonic acid. These inorganic acids and organic acids may be metal salts (for example, alkali metal salts such as sodium, alkaline earth metal salts such as calcium, group 14 metal salts of the periodic table, etc.). These acidic compounds can be used alone or in combination of two or more. Among these acidic compounds, C _1-4 aliphatic monocarboxylic acids (especially formic acid) such as formic acid are preferred from the viewpoint of excellent sinterability at low temperatures and decomposability of acid-decomposable polymers. .

As for the acid generator, conventional acid generators can be cited, for example, osmium salts (salts of cations and anions), iodonium salts (salts of cations and anions), selenium salts (salts of selenium ions and anions) ), ammonium salt (ammonium ion and anion salt), phosphonium salt (phosphonium ion and anion salt), transition metal complex ion and anion salt, allene-ion complex, aluminum chelate, three Boron fluoride complex, etc. These acid generators can be used alone or in combination of two or more. Among these acid generators, from the viewpoint of high acidity, samium salts are preferred.

Examples of samium salts include triphenylammonium salt, tri-p-tolylammonium salt, tri-o-tolylammonium salt, ginseng (4-methoxyphenyl)ammonium salt, and 1-naphthylbis Phenyl alkene salt, 2-naphthyl diphenyl alkoxide salt, ginseng (4-fluorophenyl) alkoxide salt, tri-1-naphthyl alkoxide salt, tri-2-naphthyl alkoxide salt, ginseng (4-hydroxybenzene) Group) sammonium salt, diphenyl[4-(phenylthio)phenyl]ammonium salt, 4-(p-tolylthio)phenyl bis-(p-phenyl)ammonium salt and other triarylammonium salt; diphenyl Diaryl benzyl salts such as benzyl methyl benzyl salts, diphenyl 4-nitrobenzyl methyl benzyl salts, diphenyl benzyl ammonium salts, diphenyl benzyl ammonium salts; phenyl methyl benzyl ammonium salts Salts, 4-hydroxyphenylmethylbenzyl alkoxide salts, 4-methoxyphenylmethylbenzyl alkoxide salts and other monoaryl alkoxide salts and the like.

Examples of the anions (counter ions) used to form salts with cations (cations) include: SbF ^6- , PF ^6- , BF ^4- , and fluorinated alkyl fluorophosphate ions [(CF ₃ CF ₂ ) _{^{3 PF 3-, (CF 3 CF}} 2 CF 2) 3 PF 3- _{etc.], (C 6 F 5)} 4 B -, (C 6 F 5) 4 Ga -, sulfonic acid anion (trifluoromethanesulfonic acid anion , pentafluoroethane sulfonic acid anion, a nonafluorobutane sulfonic acid anion, methanesulfonic acid anion, benzenesulfonic acid anion, toluenesulfonic acid anion, _{etc.), (CF 3 SO 2)} 3 C -, (CF 3 SO 2) 2 N ^-, perhalogen acid ion, a sulfonic acid halide ion, sulfate ion, carbonate ion, aluminate ion, a hexafluorophosphate ion bismuthate, a carboxylic acid ion, an aryl boronic acid ion, a thiocyanate ion, a nitrate ion. Among these anions, the fluoride ion such as PF ^6- is preferred.

The acid generator may be a thermal acid generator or a photoacid generator. Among these, as the thermal acid generator, commercially available products can be used, for example, "San-Aid SI-60L", "San-Aid SI-60S", "San-Aid SI-60S" manufactured by Sanxin Chemical Industry Co., Ltd. San-Aid SI-80L", "San-Aid SI-100L", "San-Aid SI-110L", or "SP-66" and "SP-77" manufactured by ADEKA Corporation. As for the photoacid generator, commercially available products can be used, for example, "HS-1", "HS-1A", "HS-1P", "HS-1N", "" manufactured by San-Apro Co., Ltd. "HS-1TF", "HS-1NF", "HS-1MS", "HS-1CS", "HS-1PC", "LW-S1", "LW-S1", "LW-S1NF", "K1- S", "CPI-101A", "CPI-100P", "CPI300PG", etc.

The decomposition aid can be selected according to the type of acid-decomposable polymer contained in the protective layer, and acid generators can be used for the polymers (1), (3) and (4), and acidic compounds can be used for the polymer (2) . Among these, from the viewpoint of simply improving the low-temperature sinterability, an acid generator is preferable, and from the viewpoint of utilizing the heat of the firing step, a thermal acid generator is particularly preferable.

The ratio of decomposition aids (acid compounds and/or acid generators) is, for example, about 0.01 to 100 parts by weight relative to 100 parts by weight of the composite fine particles The amount is preferably about 0.03 to 80 parts by weight, more preferably about 0.05 to 50 parts by weight.

In particular, when the acid-decomposable polymer is the polymer (1), (3) or (4), the ratio of the decomposition aid (particularly the acid generator) is, for example, about 100 parts by weight of the composite fine particles. 0.01 to 10 parts by weight, preferably about 0.03 to 5 parts by weight, more preferably about 0.05 to 3 parts by weight (particularly 0.08 to 2 parts by weight).

On the other hand, when the acid-decomposable polymer is the polymer (2), the ratio of the decomposition aid (especially the acidic compound) is, for example, about 1 to 100 parts by weight relative to 100 parts by weight of the composite fine particles. It is preferably about 5 to 80 parts by weight, and more preferably about 10 to 50 parts by weight (especially 20 to 40 parts by weight). In addition, the ratio of decomposition aids (especially acidic compounds) relative to the total amount of the dispersion liquid (ink) is, for example, about 1 to 30% by weight, preferably about 3 to 20% by weight, and more preferably about 5 to 15 weight%.

If the ratio of the decomposition aid is too large, the decomposition aid may remain after sintering, the conductivity may be reduced, or the stability of the dispersion may be reduced; if it is too small, the low temperature sinterability may be reduced, and the decomposition of the acid-decomposable polymer may be insufficient, resulting in conductivity reduce.

The dispersion of the present invention may contain conventional additives added to conductive paste or conductive ink according to the application. The conventional additives include, in addition to the conventional additives exemplified in the section of the protective layer, colorants (dyeing pigments, etc.), hue modifiers, dye fixing agents, gloss-imparting agents, and the like. The ratio of conventional additives may be about 50% by weight or less relative to the total amount of the dispersion, for example, about 0.01 to 10% by weight (especially 0.1 to 5% by weight).

In the case of the dispersion liquid of the present invention, when the composite fine particles obtained through the separation and purification step are obtained through a dispersion step of dispersion treatment in a dispersion medium, the aforementioned dispersion step may be a dispersion step of dispersion treatment under pressure. The pressure in the foregoing dispersion step may be about 10 MPa or more, such as about 30 to 500 MPa, preferably about 50 to 300 MPa, and more preferably about 80 to 200 MPa (especially 100 to 180 MPa). This type of dispersion under pressure can be dispersed using an ultra-high pressure disperser. If the pressure is too low, it may become difficult to prepare a uniform dispersion liquid at a high concentration. The dispersion treatment under pressure is particularly effective when the acid-decomposable polymer is the polymer (1) or (2).

In addition, as for the pretreatment of the dispersion treatment under pressure, stirring treatment (agitating treatment using a rotation/revolution mixer, etc.) and/or ultrasonic treatment (for example, ultrasonic treatment of about 10 to 100 kHz) may be performed.

[Coated film, fired film and their manufacturing method]

The coating film of the present invention can be obtained through a coating step of coating the aforementioned dispersion on a substrate. The base material may be an inorganic material or an organic material. Examples of inorganic materials include glass (soda glass, borosilicate glass, crown glass), glass containing barium, glass containing strontium, glass containing boron, low-alkali glass, and alkali-free glass , Crystallized transparent glass, silica glass, quartz glass, heat-resistant glass, etc.), metal oxides (alumina, sapphire, zirconia, titanium oxide, yttrium oxide, indium oxide-tin oxide composite oxide (ITO), fluorine Doped tin oxide (FTO), etc.). Examples of organic materials include polymethyl methacrylate resins, polypropylene resins, cyclic polyolefin resins, styrene resins, vinyl chloride resins, and polyester resins [including polyalkylenes] Aryl ester resin (poly (Ethylene terephthalate, etc.), polyarylate resin or liquid crystal polymer], polyamide resin, polycarbonate resin, poly resin resin, polyether resin, polyimide resin , Cellulose derivatives, fluororesins, etc. In particular, because it can be sintered at a low temperature, even resin substrates with low heat resistance such as polyethylene terephthalate (PET) can be sintered. The average thickness of the substrate is, for example, about 0.001 to 10 mm, preferably about 0.01 to 5 mm, and more preferably about 0.05 to 3 mm.

As for the coating method, a conventional method can be used, but in the case of forming a pattern with a coating film (wiring pattern on a wiring substrate, etc.), for example, a screen printing method, an ink jet printing method, or a gravure printing method (for example , Gravure printing (gravure printing, etc.), lithography, gravure lithography (eg, gravure offset printing, etc.), relief printing, flexographic printing, reverse printing, etc.

The average thickness of the coating film may be, for example, about 0.5 to 100 μm (eg, 1 to 20 μm), preferably about 1 to 80 μm (eg, 3 to 10 μm), and more preferably about 5 to 50 μm (particularly, 10 to 40 μm). When the coating film is a coating film patterning fine wiring, the average line width of the coating film (wiring pattern) may be, for example, about 0.5 to 30 μm, preferably about 1 to 20 μm, and more preferably about 2 to 10 μm ( Especially 3~8μm). In the present invention, since a dispersion liquid (paste or ink) containing nano-sized metal fine particles at a high concentration can be prepared, a fine wiring pattern can also be easily formed.

The fired film of the present invention is obtained through a firing step of heating and firing the obtained coating film. In the firing step, the heating temperature can exceed 200°C, however, in the case where the dispersion contains a decomposition aid, it can be carried out Low temperature sintering may be about 200°C or lower, such as about 60-200°C, preferably about 80-180°C (eg 100-175°C), more preferably about 120-170°C (especially 130-160°C) . Furthermore, when the acid-decomposable polymer is the polymer (3) or (4), and the dispersion contains a decomposition aid (especially an acid generator), sintering at a lower temperature can be performed, and the heating temperature can be about 120 Below ℃, for example about 60-120 ℃, preferably about 80-110 ℃, more preferably about 90-105 ℃.

The firing time (heating time) can be adjusted according to the firing temperature, etc. For example, it is about 10 minutes to 10 hours, preferably about 15 minutes to 8 hours, more preferably about 20 minutes to 6 hours (especially 30 minutes ~5 hours).

The firing step can be carried out in an oxygen-containing active gas environment such as air. However, from the viewpoint of suppressing the oxidation of metal fine particles, firing in an inert gas environment such as hydrogen, nitrogen, or argon is preferred. The inert gas may be a combination of two or more inert gases containing hydrogen. For example, hydrogen and nitrogen may be hydrogen/nitrogen=about 0.1/99.9~20/80, preferably about 0.5/99.5~10/90. More preferably, it is a mixed gas mixed in a volume ratio of about 1/99 to 5/95.

In the present invention, the acid-decomposable polymer can be sintered at a low temperature by decomposition. For example, in the case where the dispersion liquid contains a thermal acid generator, the acid can be generated by heating in the aforementioned firing step to polymerize the acid decomposably Decomposition.

On the other hand, a polymer decomposition step for decomposing the acid-decomposable polymer may be additionally provided according to the presence or type of the acid-decomposable polymer as a step before the firing step. For example, in the case where the dispersion contains an acidic compound, it can be set at, for example, about 35 to 100°C, preferably about 40 to 80°C, and more preferably about 45 to 60°C. Step.

In addition, when the acid-decomposable polymer is a thermal acid generator, a polymer decomposition step for decomposing the acid-decomposable polymer may be separately provided as a step before the firing step. The heating temperature in the polymer decomposition step is, for example, about 40 to 200°C, preferably about 50 to 180°C, and more preferably about 70 to 150°C.

In the case where the dispersion contains a photoacid generator, a step of irradiating visible light or ultraviolet rays to decompose the acid-generated polymer may be provided. In this polymer decomposition step, the coating film subjected to the aforementioned coating step may be subjected to light irradiation and then supplied to the firing step. In addition, the aforementioned polymer decomposition step may be a step of irradiating light simultaneously with the firing step. In addition, the aforementioned polymer decomposition step may be performed by irradiating ultraviolet rays or visible light at the stage of the dispersion liquid before the coating step to generate an acid, and then supplying it to the coating step and the firing step. As a light source for light irradiation, a conventional light source can be used, and in the case of ultraviolet rays, ultra-high to low-pressure mercury lamps, LEDs, xenon lamps, etc. can be cited.

The fired film of the present invention has excellent conductivity, and the resistivity can be about 0.5 Ω/□ or less, for example, about 0.01 to 0.5 Ω/□, preferably about 0.02 to 0.3 Ω/□, and more preferably about 0.03 to 0.1 Ω. /□.

In addition, the sintered film of the present invention may have a specific resistivity of 1×10 ^-5 Ω‧cm or less, for example, about 1×10 ^-9 ~1×10 ^-6 Ω‧cm, preferably about 1×10 ^-8 ~ 3×10 ^-6 Ω‧cm, more preferably about 5×10 ^-8 ~2×10 ^-6 Ω‧cm

[Example]

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples. Examples and comparison The polymer, coating film, and fired film obtained in the examples were evaluated by the following items.

[Molecular weight of polymer]

The weight-average molecular weight (Mw) and number-average molecular weight (Mn) of the polymer obtained in Synthesis Example 1 were connected with 3 columns ("TSKgel MultiporeHXL-M" manufactured by TOSOH Corporation) using chloroform as the mobile phase And a high-speed gel permeation column chromatograph ("HLC-8220GPC" manufactured by TOSOH Co., Ltd.) equipped with RI-8020 detector, under the conditions of 40 ℃, flow rate 1.0mL/min, and polystyrene It is calculated by conversion.

The weight-average molecular weight (Mw) and number-average molecular weight (Mn) of the polymers obtained in Synthesis Examples 2 and 3 were connected with three columns (TOSOH Co., Ltd. "TSKgel-superHZM-M") using tetrahydrofuran As a mobile phase, a high-speed gel permeation column chromatograph ("HLC-8220GPC" manufactured by TOSOH Co., Ltd.) equipped with a RI-8020 detector was carried out at 40°C and a flow rate of 0.6 mL/min. It is obtained by converting polystyrene.

[NMR of polymer]

¹ H-NMR system uses a nuclear magnetic resonance apparatus ("JNM-ECA500" manufactured by JEOL Ltd.) to measure the solvent: heavy hydrogenated chloroform; frequency: 500 MHz.

[Solubility of polymer]

A solvent was added to the polymer so that the concentration became 20% by weight, and after stirring at room temperature, the dissolved state was visually observed and evaluated by the following criteria.

○: No turbidity

×: There is turbidity.

[TG-DTA of polymer]

The TG-DTA system uses a differential thermo-thermogravimetric simultaneous measurement device ("TG-DTA6200" manufactured by SII Nano Technology Co., Ltd.), and is measured under the following conditions.

<Measurement conditions>

Environment: N ₂ 300mL/min

Temperature range: 30~550℃

Heating rate: 5℃/min

Sample tray: Al.

[Resistivity and Specific Resistivity of Fired Film]

Using a resistivity meter ("Loresta GP MCP-T610" manufactured by Mitsubishi Chemical Analysis Technology Co., Ltd.), 6 points were measured by the 4-probe method, and the average value was calculated.

[X-ray diffraction (XRD) of composite particles, coating film and fired film]

Use a desktop X-ray diffraction device ("MiniFlex II" manufactured by Rigaku Co., Ltd.) with a starting angle of 10° and a final angle of 110.005°, a sampling width of 0.015°, a scanning speed of 10.0° per minute, a voltage of 30 kV, and a current of 15 mA. Determination.

Polymer Synthesis Example 1

[Synthesis of polymer for protective layer (p-MOMPO)]

Under a dry nitrogen environment, 3.1mL of purified toluene, 0.25mL The purified heptane, 0.4 mL of tetrahydrofuran (THF), and 0.28 mL of 2-methoxy-1-methylpropylene oxide were added to the container 1 and stirred uniformly.

Then, in another container 2, 4.1 mL of purified toluene and 0.2 mL of a 1.06 M isobutoxyethyl chloride (IBVE-HCl) hexane solution were added and stirred until uniform. 0.5 mL of the resulting solution was added to container 1.

In addition, in another container 3, 3 mL of purified toluene and 1 mL of a hexane solution of 200 mM gallium chloride (GaCl ₃ ) were added, stirred until uniform, and cooled to 0°C. 0.5 mL of the resulting solution was added to the solution in container 1 cooled to 0°C, stirred uniformly, and polymerization was started, and stirring was continued for 4 hours (the polymerization temperature was maintained at 0°C).

In addition, all the containers (container 1, container 2, and container 3) use glass containers with tripartite stoppers installed. In a dry nitrogen environment, an industrial jet with a hot air output of about 400°C is used for 10 minutes to remove the adsorbed water. By.

The concentration of each component at the start of polymerization is shown below.

[2-methoxy-1-methylpropylene oxide]=0.5M

[IBVE-HCl]=5mM

[GaCl ₃ ]=5mM

[THF]=1M.

Then (after stirring for 4 hours), 3 mL of methanol containing about 1% ammonia water was added to stop the polymerization. The mixture (solution) for stopping the polymerization was diluted with about 20 mL of methylene chloride, washed with water to remove catalyst residues, and then the product (polymer) was recovered by evaporating the solvent or the like.

The aforementioned polymerized monomer (2-methoxy-1-methylpropylene oxide) The conversion rate was 89% (polymerization time: 4 hours). In addition, the weight average molecular weight (Mw) of the obtained polymer was 5,300, and the molecular weight distribution (Mw/Mn) was 1.30.

When the ¹ H-NMR spectrum of the obtained polymer was measured, it was confirmed that a polymer having an acetal structure (ring-opening polymer) was formed in the main chain. Fig. 1 shows the ¹ H-NMR spectrum of the obtained polymer. The proton to which the peak of the ¹ H-NMR spectrum belongs is shown in Fig. 1. In the first graph, the integral ratio of peaks of g protons, b, c, h, and k protons, peaks of a, f, and i protons [g: (b, c, h, k): (a , F, i)] is 1:3:6. The NMR data of the obtained polymer are shown below.

(NMR data)

¹ H-NMR (CDCl ₃ ): δ (ppm) 4.4-4.2(m), 4.1-3.9(m), 3.7-3.3(m), 1.9-1.7(m), 1.4-1.1(m), 1.0- 0.8(m).

Polymer Synthesis Example 2

[Synthesis of protective layer polymer (p-ISB)]

5g of isosorbide (made by Tokyo Chemical Industry Co., Ltd.) and 0.43g of pyridinium p-toluenesulfonate (made by Tokyo Chemical Industry Co., Ltd.) were added to 20g of propylene glycol monomethyl ether acetate (Daicel Corporation) Co., Ltd.), and 6.78 g of isosorbide divinyl ether (manufactured by Daicel Co., Ltd.) was added dropwise below 30°C. After dropping, the mixture was stirred at 40°C for 4 hours. The undissolved portion of isosorbide exists at the beginning of the reaction, and the undissolved portion of isosorbide disappears at the end of the reaction. After the reaction was completed, it was washed with a 5 wt% sodium bicarbonate aqueous solution and water, and the organic layer was concentrated under reduced pressure to obtain 7 g of a polymer. The weight-average molecular weight Mw of this polymer was 5200, and the molecular weight distribution (Mw/Mn) was 2.2. The resulting polymer The NMR data is shown below, and the NMR graph is shown in the second figure.

(NMR data)

¹ H-NMR (CDCl ₃ ): δ (ppm) 1.334-1.344(d), 1.386-1.397(d), 3.858-4.006(m) 4.029-4.063(m), 4.232-4.352(m), 4.410-4.419 (m), 4.526-4.567(m), 5.045-5.091(m), 6.352-6.487(m).

Furthermore, after dissolving 10 mg of the obtained polymer in 4.5 g of tetrahydrofuran, 0.5 g of 1N hydrochloric acid was added, and the mixture was heated at 50° C. for 30 minutes. When the weight average molecular weight Mw of the hydrochloric acid-treated product is measured, the peak of the weight body disappears. On the other hand, 10 mg of the obtained polymer was dissolved in 5 g of tetrahydrofuran and heated at 50° C. for 30 minutes. When the weight average molecular weight Mw was measured, it was confirmed that the peak of the weight body did not change.

Polymer Synthesis Example 3

[Synthesis of protective layer polymer (p-BDO)]

57.2g of 1,4-butanediol (manufactured by Tokyo Chemical Industry Co., Ltd.) and 1.59g of pyridinium p-toluenesulfonate (manufactured by Tokyo Chemical Industry Co., Ltd.) were added to 265g of molecular sieve (Wako Pure Pharmaceutical Industry Co., Ltd. "4A 1/16") dehydrated propylene glycol monomethyl ether acetate (made by Daicel Co., Ltd.) and stirred, then 100.2g of 1,4-butanediol was added dropwise at 40°C Divinyl ether (manufactured by Sigma Aldrich). After dropping, it was stirred at 40°C for 2 hours. After the reaction was completed, 5 g of butylamine was added to quickly stop the reaction. Then, after ethyl acetate was added, it was washed with water, and the organic layer was concentrated under reduced pressure to obtain a polymer with a yield of 72%. The weight average molecular weight Mw of this polymer was 9000, and the molecular weight distribution (Mw/Mn) was 2.1. The NMR data of the obtained polymer are shown below , And the NMR chart is shown in Figure 3.

(NMR data)

¹ H-NMR (CDCl ₃ ): δ (ppm) 1.285-1.295(d), 1.617-1.633(m), 3.387-3.457(m), 3.554-3.629(m), 4.651-4.683(q), 6.441- 6.482 (dd).

Furthermore, after dissolving 0.4 g of the obtained polymer in 1.1 g of tetrahydrofuran, 0.3 g of 5N hydrochloric acid was added, and the mixture was stirred at room temperature for 30 minutes. When the weight average molecular weight Mw of the hydrochloric acid-treated product was measured, the peak of the polymer disappeared. On the other hand, 0.4 g of the obtained polymer was dissolved in 1.1 g of tetrahydrofuran and stirred at room temperature for 30 minutes. When the weight average molecular weight was measured, it was confirmed that there was no change in the peak of the polymer.

In addition, the measurement result of TG-DTA of the obtained polymer is shown in FIG. 4, and the result of evaluating solubility is shown in Table 1.

Synthetic example of composite particles 1

[Synthesis of copper particles coated with p-MOMPO]

1.2802g of the polymer obtained in Synthesis Example 1 After p-MOMPO was dissolved in 20 mL of tetrahydrofuran solution containing 0.4 M of ammonia at room temperature, 0.8094 g of copper (II) oxide ("N-130" manufactured by Nissin Chemco Co., Ltd.) was added and heated to 60°C while stirring , And add 24mL of a tetrahydrofuran solution containing 1M hydrazine under stirring. After 12 minutes of addition, foaming from the reaction liquid was confirmed. After the foaming was completed, the reaction was continued at 60°C for 2 hours. After the reaction was completed, the generated particles were filtered with a filter with a diameter of 0.2 μm, and the filtered particles were washed with tetrahydrofuran and water, and vacuum-dried at room temperature to obtain 0.5 g of p-MOMPO-coated copper particles (Composite particles). The composite fine particles were observed with SEM (50,000 times), and when the particle diameter was measured, the median diameter was 123.8 nm. The measurement results of SEM are shown in Fig. 5.

Synthetic example of composite particles 2

[Synthesis of copper particles coated with p-ISB]

3.3 g of p-ISB obtained in Polymer Synthesis Example 2 and 12.5 g of copper (II) sulfate 5 hydrate were added to 10 mL of distilled water, and stirred at 50° C. for 1 hour to dissolve. 12.5 mL of hydrazine monohydrate was added to this mixed liquid, and it stirred at 50 degreeC for 3 hours, and was made to react. Distilled water was added to the reaction solution, and it was centrifugally settled at 5000 rpm for 5 minutes. After washing twice by gentle tilting, ethanol was further added, and it was centrifugally settled at 5000 rpm for 5 minutes, and then washed twice by gentle tilting. The obtained particles were dried at room temperature in a nitrogen atmosphere to obtain 3.2 g of p-ISB-coated copper fine particles (composite fine particles). The composite fine particles were observed by SEM (50,000 times), and the median diameter was 90 nm when the particle size was measured. The measurement result of SEM is shown in FIG. 6.

Synthesis Example 3 of Composite Particles

[Synthesis of copper particles coated with p-BDO]

In 500 mL of tetrahydrofuran, after dissolving 1.67 g of p-BDO obtained in Polymer Synthesis Example 3 at room temperature, 20 g of copper (II) oxide ("N-130" manufactured by Nissin Chemco Co., Ltd.) was added While stirring and heating to 50°C, 12.5 mL of hydrazine monohydrate was added to the mixture, and the mixture was stirred at 50°C for 3 hours to react. Distilled water was added to the reaction solution, centrifugal sedimentation was performed at 5000 rpm for 5 minutes, and washing was performed twice in a gentle tilting manner, ethanol was further added, and centrifugal sedimentation was performed at 5000 rpm for 5 minutes, and then washed twice in a gentle tilting manner. The obtained copper particles were dried at room temperature under a nitrogen atmosphere to obtain 16.02 g of p-BDO-coated copper fine particles (composite fine particles). The composite fine particles were observed by SEM (25,000 times), and when the particle diameter was measured, the median diameter was 150.9 nm. The measurement result of SEM is shown in FIG. 7. In addition, the X-ray diffraction (XRD) of the composite particles was measured. The measurement results of XRD are shown in Fig. 8.

Example 1

(Manufacturing and firing evaluation of copper ink)

The copper fine particles (composite fine particles) coated with p-MOMPO were sieved with a 60-mesh sieve, and the composite fine particles passing through the sieve were crushed with a mortar. Add 50mL of methanol to 0.1260g of composite particles and stir for 8 minutes with a mixer ("Hybrid/Revolution Hybrid-Mixer" manufactured by THINKY Co., Ltd.), irradiate 40kHz ultrasonic wave for 10 minutes, and use a 400 mesh filter filter. Using an ultra-high pressure dispersing machine ("Star Burst" manufactured by Sugino Machine Co., Ltd.), the filtrate was subjected to dispersion treatment 5 times at a spray pressure of 150 MPa and once at 100 MPa to obtain a dispersion liquid of composite fine particles. Remove methanol from this dispersion under reduced pressure to make methanol After the content became 50% by weight, an acid generator ("SI-110L" manufactured by Sanshin Chemical Industry Co., Ltd.) was added to the composite fine particles by 0.1% by weight to obtain a copper ink. Using a doctor blade, the copper ink was coated on an alumina plate with a film thickness of 20 μm, and fired at 150° C. under nitrogen mixed with 3% hydrogen for 4 hours. The surface resistance of the coating film after firing was 0.232Ω/□. X-ray diffraction (XRD) of composite particles, coated film and fired film was measured. The measurement results of XRD are shown in Fig. 9.

Example 2

After adding 3.0 g of p-ISB-coated copper fine particles (composite fine particles) and 7.0 g of α-terpineol to 30 mL of methanol, it was stirred using a mixer (“rotation/revolution Hybrid-Mixer” manufactured by THINKY Co., Ltd.) 32 minutes. After stirring, an ultra-high pressure dispersing machine ("Star Burst" manufactured by Sugino Machine Co., Ltd.) was used to perform a dispersion treatment 5 times at a spray pressure of 150 MPa to obtain a dispersion liquid of composite fine particles. This dispersion liquid was concentrated under reduced pressure, and after removing methanol, 0.13 mL of formic acid was added to 1.4 mL of the concentrated liquid to obtain a copper ink. Using a doctor blade, apply the copper ink to a bauxite plate with a film thickness of 40 μm, perform desolvation at 60°C under nitrogen for 2 hours, and fire at 150°C under nitrogen mixed with 3% hydrogen 2 hour. The resistivity of the coating film after firing was 0.3036Ω/□. X-ray diffraction (XRD) of composite particles, coated film and fired film was measured. The XRD measurement result is shown in Fig. 10.

Example 3

A copper ink was obtained in the same manner as in Example 1, except that no acid generator was added in Example 1. Using a doctor blade, apply the copper ink to the alumina plate with a film thickness of 20 μm, and remove the solvent at 200° C. in air After 4 hours, firing was carried out at 200°C under nitrogen mixed with 3% hydrogen for 2 hours. The resistivity of the coating film after firing is 0.071Ω/□. The X-ray diffraction (XRD) of the composite particles, the coating film after coating, the coating film after solvent removal, and the fired film was measured. The XRD measurement results are shown in Fig. 11.

Example 4

(Evaluation of conductivity of copper particles by hot pressing)

Mix 1 g of the composite particles obtained in Synthesis Example 3 of the composite particles with 10 mg of an acid generator ("SI-100" manufactured by Sanshin Chemical Industry Co., Ltd.) at various temperatures in Table 2 under air. Hot pressing (Φ13 mm) was performed at 100 MPa for 30 minutes. On the other hand, 1 g of the composite fine particles obtained in Synthesis Example 3 of composite fine particles was subjected to hot pressing (Φ13 mm) at 100 MPa for 30 minutes at 100 MPa at various temperatures in Table 2. Table 2 shows the film thickness and specific resistivity of the obtained copper film.

As the results in Table 2 clearly show, the pressure (100 MPa) at room temperature (25°C) shows about 10 ^-6 Ω‧cm. Regardless of the presence or absence of the acid generator, at 80 ℃, 100 MPa, the specific resistivity is reduced to 1.5×10 ^-6 and 1.4×10 ^-6 Ω‧cm; in addition, in the presence of the acid generator A, due to 100 Heating/pressurization at ℃ and 100MPa reduces the specific resistance to 2.9×10 ^-7 Ω‧cm. This phenomenon can be presumed because the acid is generated from the acid generator at 100°C, and the polymer is decomposed.

[Industry availability]

The composite particles of the present invention can be used in the formation of various conductors according to the form of conductive ink or conductive paste. However, because the metal particles are nano-sized, they can be adjusted to high-concentration inks or pastes, which can be effectively used The formation of high-density fine wiring patterns. Therefore, the composite fine particles of the present invention are preferably used for a transparent wiring board on which a fine wiring pattern is formed, and an electronic device provided with the wiring board.

Claims (14)

A composite particle comprising copper particles and a protective layer covering at least a part of the surface of the copper particles and containing an acid-decomposable polymer with an average particle size of 10 to 500 nm. The acid-decomposable polymer It has a repeating unit represented by the following formula (1), a repeating unit represented by the following formula (2), a repeating unit represented by the following formula (3), or represented by the following formulas (4a) and (4b) Two kinds of repeating units;

In the formula, R ¹ to R ³ , each of which is the same as or different from each other, represents a hydrogen atom, a halogen atom, a hydroxyl group, a hydroperoxy group, an amine group, a thiol group, a sulfonic acid group, or an organic group, and R ¹ to R ³ Two or more of them can be bonded to each other to form a ring; R ⁴ represents a halogen atom, a hydroxyl group, a hydroperoxy group, an amine group, a thiol group, a sulfonic acid group or an organic group;

In the formula, ring Z represents a saturated heterocyclic ring which may have a substituent and contains an oxygen atom as a hetero atom, and ring Z may be the same combination of the aforementioned saturated heterocyclic rings or a combination of different saturated heterocyclic rings;

In the formula, A ¹ represents a hydrocarbon group which may have a substituent, -A ² -(OA ³ ) _n -group; in the formula, A ² and A ³ , each of which is the same or different from each other, represent a hydrocarbon group which may have a substituent, n It is an integer above 1;

In the formula, A ⁴ represents a hydrocarbon group which may have a substituent, -A ⁶ -(OA ⁷ ) _m -group; in the formula, A ⁶ and A ⁷ , each of which is the same as or different from each other, represents a hydrocarbon group which may have a substituent, m Is an integer of 1 or more; A ⁵ represents a hydrocarbon group which may have a substituent, -A ⁸ -(OA ⁹ ) _k -group; in the formula, A ⁸ and A ⁹ , each of which is the same as or different from each other, means that it may have a substituent Hydrocarbon group, k is an integer of 1 or more; A ⁴ and A ⁵ are different groups. A method for manufacturing composite particles as claimed in claim 1, comprising a coating step of coating at least a part of the surface of the copper particles with an acid-decomposable polymer. The manufacturing method according to claim 2, wherein in the coating step, at least one raw material copper compound selected from the group consisting of copper oxide, copper salt and copper halide is reduced in the presence of an acid-decomposable polymer . The manufacturing method according to claim 3, wherein the raw material copper compound is at least one selected from the group consisting of copper oxide, copper sulfate, copper formate, copper acetate, and copper chloride, and hydrazine is used as a reducing agent. A dispersion liquid comprising the composite fine particles according to claim 1 and a dispersion medium selected from the group consisting of alcohol-based solvents, ester-based solvents, ketone-based solvents, ether-based solvents, aromatic-based solvents, halogen-based solvents, and nitriles At least one of the group of solvents and nitro solvents, and the ratio of the dispersion medium to 100 parts by weight of the composite particles, It is 10~1000 parts by weight. The dispersion liquid according to claim 5, which further contains an acidic compound and/or an acid generator. The dispersion liquid according to claim 5 or 6, further contains a reducing agent. If the dispersion liquid of claim 5 or 6, it is conductive ink or conductive paste. A method for manufacturing a dispersion liquid according to any one of claims 5 to 8, which includes a dispersion step of performing a dispersion process under pressure. A method for manufacturing a coating film, which comprises applying a dispersion liquid according to any one of claims 5 to 8 on a substrate. A method for manufacturing a fired film, which includes a firing step of heating and firing the coating film obtained by the method of claim 10. The manufacturing method according to claim 11, wherein the firing temperature is below 200°C, and firing is performed in an inert gas environment. The manufacturing method according to claim 11 or 12, wherein the resistivity of the obtained fired film is 0.5 Ω/□ or less. A method of using a fired film obtained by the manufacturing method according to any one of claims 11 to 13 as a wiring substrate.

Images