JPS6320446B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a conductive resin composition with improved adhesion. More specifically, the present invention relates to a conductive resin composition that is cured by actinic light such as ultraviolet rays and then completely cured by heat treatment, resulting in significantly improved conductivity and adhesiveness. Conventionally, conductive resin compositions have been used to form circuits by coating or printing and drying or curing with heat, to bond terminals and lead wires in resistors and semiconductor components, and to bond components. It is widely used to protect electronic equipment from electromagnetic interference (EMI). Currently, this conductive resin composition is made of conductive metal powder such as silver powder or nickel powder, or carbon powder such as carbon black or graphite, combined with phenol resin, melamine resin, xylene resin, acrylic resin, alkyd resin, epoxy resin, or urethane resin. The mainstream is a combination of synthetic resins such as resins (hereinafter referred to as binders) depending on the purpose of use, and a mixture and kneading with a solvent added thereto. However, although conventional conductive resins have been sufficiently considered in terms of properties such as conductivity and solvent resistance, on the other hand, there is no conductive resin that has adhesive properties, printability, and excellent work efficiency. This is the reality. In other words, among conventional conductive resin compositions, heat-drying conductive resin compositions made by adding a solvent to thermoplastic resins such as acrylic resins and polyester resins, and further adding a small amount of crosslinking agent as necessary, have poor adhesive properties. Although it is excellent, the solvent volatilizes during screen printing or coating, and the viscosity of the resin composition gradually increases, resulting in clogging of the plate and coagulation of the resin, resulting in damage to the formed circuits and bonded electronics. Parts become less reliable. In addition, it has poor heat resistance and solvent resistance. In addition, thermosetting conductive resin compositions that use condensation resins such as phenol resins, melamine resins, xylene resins, epoxy resins, and alkyd resins as binders are Shrinkage is large, and since it often contains solvents, the shrinkage becomes even larger, resulting in large internal strains in the binder after curing, which can adversely affect adhesion and cause cracks due to large shrinkage. There is a defect. In addition, thermosetting conductive resin compositions have major problems in terms of work efficiency, work environment, and energy consumption, and because they require heating at relatively high temperatures for long periods of time, they can cause thermal deterioration of the base material and bonded parts. Another problem arises. We have conducted repeated research to improve the shortcomings of conventional conductive resin compositions, and found that they are composed of an epoxy compound, a photopolymerizable compound having a carboxyl group in the molecule, and a photoinitiator, and can be cured by actinic rays such as ultraviolet rays. We have already discovered and proposed a conductive resin composition using a binder that combines the curing reaction of an epoxy group and a carboxyl group (Japanese Patent Application No. 1983-
No. 164824). However, although the conductive composition has excellent conductivity and printability, and has greatly improved work efficiency and work environment, it has been found that there is still room for improvement in terms of adhesiveness. As a result of further intensive research, the present inventors discovered that the adhesiveness could be improved by adding an organic titanate compound to the conductive resin composition, and arrived at the present invention. That is, the present invention
Conductive fine powder (A), epoxy compound having at least two epoxy groups in the molecule (B), photopolymerizable compound having carboxyl group in the molecule (C), or photopolymerization of said compound (C) with other materials This is a conductive resin composition characterized by containing a mixture with a chemical compound (D), a photoinitiator (E), and an organic titanate compound (F). To cure the conductive resin composition of the present invention, first, a photopolymerizable compound (C) having a carboxyl group in the molecule or a mixture of the compound (C) and another photopolymerizable compound (D) is heated with actinic rays. It consists of a two-step curing method: polymerization to form a carboxyl group-containing polymer, and then heating to completely cure the epoxy compound (B) by reacting with the carboxyl group-containing polymer. The conductive resin composition of the present invention does not essentially require a volatile solvent, and a photopolymerizable compound (C) having a carboxyl group in the molecule or another photopolymerizable compound (D) is selected in the composition. By doing this, the viscosity of the binder can be freely adjusted, greatly improving work efficiency and the working environment. Unlike solvent-containing conductive resin compositions, the viscosity increases during printing or coating, resulting in better reproducibility. It does not have the drawbacks that it becomes impossible to form a circuit or that the resin solidifies, resulting in poor reliability of the circuit or bonded part. Furthermore, since a carboxyl group-containing polymer is generated by active light such as ultraviolet rays in the first stage of curing, curing by heating in the second stage of curing is performed at a lower temperature than that of conventional thermosetting conductive resin compositions. Since it can be thermally cured at a temperature, problems such as thermal shrinkage and thermal deterioration of the base material are unlikely to occur. In addition, since ultraviolet rays and heat curing are used together, the binder is completely cured, and therefore has excellent electrical conductivity and stability. Moreover, since such a two-step curing method is used, internal strain can also be suppressed. Further, in the present invention, by adding the organic titanate compound (F), although the conductivity tends to decrease slightly, the adhesiveness can be greatly improved. It has been known to use coupling agents in paints and adhesives to improve their adhesion. The coupling agent has the effect of improving adhesiveness by increasing the adhesion between the filler in the composition and the binder, and between the binder and the adhesive base material. In general, silane-based, titanium-based, and borane-based coupling agents are known as coupling agents, but in the present invention, even if silane-based and borane-based coupling agents are used, the adhesion does not improve, and the coupling agent Only when an organic titanate compound is used as the agent, the effect of improving adhesion is specifically exhibited. In other words, the organic titanate compound (F) interacts with the organic binder and the conductive fine powder (A) to uniformly wet the conductive fine powder (A) with the binder. The dispersion of
Adhesion properties are greatly improved. Therefore, the flexibility and crack resistance inherent in the binder can be fully exhibited. By adding the organic titanate substance in this way, a conductive resin composition with excellent adhesiveness can be obtained. A composition in which an organic titanate compound (F) is added to a conductive resin has already been proposed. For example, JP-A No. 50-6638 describes a conductive paint, and describes a silane coupling agent, a silane coupling agent, which can directly bond to the metal by reducing the metal oxide formed on the surface of the conductive metal. Three types of substances are described: borane coupling agents and titanium coupling agents. In this publication, copper, nickel, aluminum, etc. are exemplified as conductive powder metals, and coupling agents are used as antioxidants for these base metals. Also, JP-A-56-
Publication No. 36553 describes a conductive resin composition in which copper or a copper alloy, an organic titanate substance, and a binder are combined. Similar to the above publication, this publication also uses an organic titanate substance as an antioxidant for copper powder or copper alloy powder, and therefore it is desirable that the organic titanate substance be about 2% to 12% of the pigment substance. , the best results are stated to range from about 3% to about 10%, and large amounts need to be added. Examples of the conductive fine powder (A) used in the present invention include metal powders such as gold, silver, nickel, palladium, and platinum, inorganic powders coated with these metals, silver oxide, indium oxide, tin oxide, and metal powders coated with these metals. zinc,
Examples include powders of metal oxides such as ruthenium oxide, and inorganic powders coated with these metal oxides. However, in the composition of the present invention, easily oxidized metals such as copper, chromium, aluminum, tungsten, and molybdenum are not suitable as the conductive metal powder A. These conductive fine powders (A) may be used alone or in combination of two or more. There is no limit to the shape of this conductive fine powder; it can be granular,
Flakes, scales, plates, resins, dices, etc. can be used, and their sizes range from 0.1μm to 100μm.
m can be used, but generally 0.1μm~
20 μm is used. The surface of these conductive fine powders (A) may be surface-treated with, for example, oil or fat. In addition to the above-mentioned conductive fine powders, other conductive fine powders such as carbon powders such as carbon black, ketone black, and acetylene black, and graphite powders can also be used. It can also be used in combination with powder. The amount of these conductive fine powders is 45 to 95% by weight, preferably 50 to 95% by weight of the conductive resin composition of the present invention.
It is 90% by weight. If the amount of conductive fine powder is less than 45% by weight, practically no practical conductivity will be obtained, and if it exceeds 95% by weight, the amount of binder will be too small, resulting in poor printability, coating properties, adhesive properties, etc. decreases significantly. The epoxy compound (B) having at least two epoxy groups in the molecule used in the present invention is an epoxy compound having two or more epoxy groups in one molecule, and its epoxy equivalent is 100 to 4000, preferably It is 100-1000. Representative compounds include bisphenol A,
Bisphenol F, halogenated bisphenol A
Representative examples include bisphenol type epoxy resins, which are diglycidyl ethers such as 2, and novolac type epoxy resins, which are polyglycidyl ethers such as phenol novolak and cresol novolak.
polyglycidyl ethers of polyhydric phenols with a valence of more than 2, polyhydric alcohols with a valence of 2 or more such as ethylene glycol, propylene glycol, neopentyl glycol, 1,4-butanediol, 1,6-hexanediol, trimethylolpropane, etc. Polyglycidyl ethers of phthalic acid, isophthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, polyglycidyl esters of divalent or higher polycarboxylic acids such as adipic acid, aniline, isocyanuric acid, etc. polyglycidyl ethers in which the active hydrogen is substituted with a glycidyl group, vinylcyclohexene diepoxide obtained by epoxidizing the olefin bond in the molecule, 3,4-epoxycyclohexylmethyl-
3,4-epoxycyclohexanecarboxylate, 2-(3,4-epoxy)cyclohexyl-
Alicyclic polyepoxy compounds such as 5,5-spiro(3,4-epoxy)cyclohexane-m-dioxane, N,N,N',N'-tetraglycidyl metaxylene diamine, N,N,N', Examples include aminopolyepoxy compounds such as N'-tetraglycidyl-1,3-bis(aminomethyl)cyclohexane. These epoxy compounds can be used alone or in combination of two or more. In addition, one epoxy group is added in the molecule of allyl glycidyl ether, phenyl glycidyl ether, etc.
It can also be used in combination with its own epoxy compounds. Among these epoxy compounds having at least two epoxy groups in the molecule, preferred epoxy compounds include diglycidyl ether of bisphenol A, phenol novolak type polyepoxy compounds, and cresol novolak type polyepoxy compounds. can give. Examples of the photopolymerizable compound (C) having a carboxyl group in the molecule used in the present invention include (i) unsaturated carboxylic acid compounds such as acrylic acid, methacrylic acid, itaconic acid, crotonic acid, and fumaric acid; , (ii) Hydroxyethyl (meth)acrylate (meaning acrylate and methacrylate).
The same abbreviation will be given below. ), hydroxyl group-containing (meth)acrylates such as hydroxypropyl (meth)acrylate, and phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, succinic anhydride, maleic anhydride, trimellitic anhydride, pyromellitic anhydride, etc. Compounds obtained by reacting with polybasic acid anhydrides, such as phthalic acid mono(meth)acryloyloxyethyl ester, succinic acid mono(meth)acryloyloxyethyl ester, maleic acid mono(meth)acryloyloxyethyl ester, etc. Representative compounds include (iii) compounds obtained by reacting glycidyl (meth)acrylate with polybasic acids such as succinic acid, maleic acid, ortho, iso, and terephthalic acids, such as mono(2-hydroxy-3 -Compounds represented by methacryloyloxypropyl) phthalate, mono(2-hydroxy-3-acryloyloxypropyl)succinate, etc.
(iv) Oligoester (meth)acrylates having a carboxyl group in the molecule obtained by reacting polyhydric alcohols with polyhydric carboxylic acids and acrylic acid or methacrylic acid. As the photopolymerizable compound (C) having a carboxyl group in the molecule, among the above-mentioned compounds, in particular (ii),
(iii) and (iv) are preferred. These photopolymerizable compounds (C) having a carboxyl group in the molecule can be used alone or in combination with two or more, or in combination with one or more of the other photopolymerizable compounds (D) described below. used. The compounding ratio of the epoxy compound (B) having at least two epoxy groups in the molecule and the photopolymerizable compound (C) having a carboxyl group in the molecule used in the present invention is such that the equivalent ratio of epoxy groups to carboxyl groups is 1:
The range is 3 to 33:1, preferably epoxy group equivalent: carboxyl group = (n/m): (6/m) to (3n/m): (1/m) (where m is within the molecule The number of carboxyl groups in the photopolymerizable compound (C) having a carboxyl group, n is a positive integer representing the number of epoxy groups in the epoxy compound, and is in the range of 1≦m, 2≦n≦11). Equivalence ratio of epoxy group and carboxyl group is 1:3
If the value of epoxy group equivalent/carboxyl group equivalent is less than 0.33, the hardness will be insufficient. On the other hand, if the equivalent ratio of epoxy group to carboxyl group exceeds 33:1, that is, epoxy group equivalent/
If the value of carboxyl group equivalent exceeds 33, curability decreases, which is not preferable. The photopolymerizable compound (D) used in the present invention is a photopolymerizable compound having one or more photopolymerizable double bonds in the molecule. Examples of photopolymerizable compounds having one photopolymerizable double bond in the molecule include (i) styrene;
Styrenic compounds such as α-methylstyrene and chlorostyrene, (ii) methyl (meth)acrylate, ethyl (meth)acrylate, n- and i
-Propyl (meth)acrylate, n-, sec-
and alkyl (meth)acrylates such as t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate , alkoxyalkyl (meth)acrylates such as butoxyethyl (meth)acrylate, allyloxyalkyl (meth)acrylates such as phenoxyethyl (meth)acrylate, hydroxyalkyl (meth)acrylates such as hydroxyethyl (meth)acrylate, halogens Substituted alkyl (meth)acrylates, or substituted alkyls such as polyoxyalkylene glycol mono(meth)acrylates such as polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, or alkoxypolyoxylalkylene mono(meth)acrylate Mono(meth)acrylates, heterocycle-containing (meth)acrylates such as tetrahydrofurfuryl (meth)acrylate, (iii) bisphenol A
mono(meth)acrylates of alkylene oxide adducts of bisphenol A, such as ethylene oxide and propylene oxide adducts; alkylene oxide adducts of hydrogenated bisphenol A, such as ethylene oxide and propylene oxide adducts of hydrogenated bisphenol A; Things (meta)
Acrylates, (iv) diisocyanate compound and 2
One (meth)acryloyloxy group in the molecule obtained by further reacting a terminal isocyanate group-containing compound obtained by preliminarily reacting two or more alcoholic hydroxyl group-containing compounds with an alcoholic hydroxyl group-containing (meth)acrylate. (v) epoxy mono(meth)acrylates obtained by reacting a compound having one or more epoxy groups in the molecule with acrylic acid or methacrylic acid, and (vi) Acrylic acid or methacrylic acid and polyhydric carboxylic acid as carboxylic acid component and 2 as alcohol component
There are oligoester mono(meth)acrylates obtained by reacting polyhydric alcohols with higher valences. Examples of photopolymerizable compounds having two photopolymerizable double bonds in the molecule include (i) ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, 1,4-butanediol di (meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-
Alkylene glycol di(meth)acrylates such as hexanediol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate , polypropylene glycol di(meth)
Polyoxyalkylene glycol di(meth)acrylates such as acrylates, substituted alkylene glycol di(meth)acrylates such as halogen-substituted alkylene glycol di(meth)acrylates, (ii) ethylene oxide and propylene oxide adducts of bisphenol A, etc. di(meth)acrylates of alkylene oxide adducts of bisphenol A, di(meth)acrylates of alkylene oxide adducts of hydrogenated bisphenol A, such as ethylene oxide and propylene oxide adducts of hydrogenated bisphenol A; iii) A terminal isocyanate group-containing compound obtained by reacting a diisocyanate compound and two or more alcoholic hydroxyl group-containing compounds in advance is further reacted with an alcoholic hydroxyl group-containing (meth)acrylate; Epoxy di(meth)acrylates obtained by reacting urethane-modified di(meth)acrylates having (meth)acryloyloxy groups, (iv) compounds having two or more epoxy groups in the molecule with acrylic acid and/or methacrylic acid. Acrylates, (v) oligoester di(meth) obtained by reacting acrylic acid or methacrylic acid and polyhydric carboxylic acid as the carboxylic acid component with a polyhydric alcohol of dihydric or higher valence as the alcohol component
There are acrylates, etc. Examples of photopolymerizable compounds having three or more photopolymerizable double bonds in the molecule include (i) trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth)acrylate,
Poly(meth)acrylates of trivalent or higher aliphatic polyhydric alcohols such as pentaerythritol tetra(meth)acrylate, poly(meth)acrylates of trivalent or higher halogen-substituted aliphatic polyhydric alcohols, (ii) diisocyanate compounds A terminal isocyanate group-containing compound obtained by reacting a compound containing three or more alcoholic hydroxyl groups in advance with a (meth)acrylate containing an alcoholic hydroxyl group has three or more (meth)acryloyl groups in the molecule. Urethane-modified poly(meth)acrylates having an oxy group, (iii) epoxy poly(meth)acrylates obtained by reacting a compound having three or more epoxy groups in the molecule with acrylic acid or/and methacrylic acid, etc. There is. Epoxy compound (B) used in the present invention and the above photopolymerizable compound having a carboxyl group in the molecule
The mixing ratio of (C) or the compound (C) and other photopolymerizable compound (D) is epoxy compound (B):photopolymerizable compound [(C)
or (C) + (D)] = 10:90 to 90:10 (weight ratio), preferably epoxy compound (B): photopolymerizable compound [(C) or (C) + (D) ]=20:80 to 80:20 (weight ratio). The amount of epoxy compound (B)
If the amount is less than 10% by weight, the above photopolymerizable compound (C) having a carboxyl group in the molecule and the epoxy compound
The reaction with (B) is substantially too small, making it difficult to obtain a cured product with excellent adhesiveness and chemical resistance. In addition, if the amount of epoxy compound (B) exceeds 90% by weight,
The viscosity of the binder increases, making it difficult to handle. These binders [(B) + (C) or (B) + (C) + (D)]
The blending amount is 5 to 55% by weight, preferably 10 to 50% by weight of the conductive resin composition of the present invention. When the binder content is less than 5% by weight, printability, coating properties, and adhesive properties are significantly reduced, and when it is 55% by weight or more, practical conductivity cannot be obtained. The photoinitiator (E) used in the present invention is a compound that promotes the photopolymerization reaction of a photopolymerizable compound, such as ketals such as benzyl dimethyl ketal, benzoin methyl ether, benzoin ethyl ether, benzoin-i - Benzoins such as propyl ether, benzoin, α-methylbenzoin, 9,10-anthraquinone, 1-chloroanthraquinone, 2-chloroanthraquinone,
Anthraquinones such as 2-ethylanthraquinone, benzophenones such as benzophenone, p-chlorobenzophenone, p-dimethylaminobenzophenone, 1-phenyl-2-hydroxy-2-methyl-1-propion, 1-(4 Propiophenones such as -isopropylphenyl)-2-hydroxy-2-methyl-1-propion,
Examples include suberones such as dibenzosuberone, sulfur-containing compounds such as diphenyl disulfide, tetramethylthiuram disulfide, and thioxanthone, and pigments such as methylene blue, eosin, and fluorescein, used alone or in combination of two or more. used. In the present invention, the blending amount of the photoinitiator is 0.05 to 20% by weight in the conductive resin composition, preferably
It is 0.5-10% by weight. Photoinitiator content is 0.05
If the amount is less than 20% by weight, the photopolymerizable compound cannot be sufficiently polymerized, and the amount of photoinitiator added is 20% by weight.
In the above case, chemical resistance and hardness decrease. In the present invention, when it is necessary to promote the reaction between an epoxy group and a carboxyl group, it is effective to add a reaction promoter. As a reaction accelerator,
For example, 2-methylimidazole, 2-ethylimidazole, 2,4-dimethylimidazole, 2
-Ethyl-4-methylimidazole, 2-undecylimidazole, 2-heptadecyl imidazole, 1-vinyl-2-methylimidazole, 2-
Phenylimidazole, 1-vinyl-2-ethylimidazole, imidazole, 2-phenyl-4
-Methylimidazole, 1-vinyl-2,4-dimethylimidazole, 1-vinyl-2-ethyl-
imidazoles such as 4-methylimidazole,
Benzyldimethylamine, 2,4,6-tridimethylaminophenol, triethanolamine,
Triethylamine, N,N'-dimethylpiperidine, α-methylbenzyldimethylamine, N-methylmorpholine, dialkylaminoethanol,
Examples include tertiary amines such as dimethylaminomethylphenol, and tertiary amine salts such as triacetate and tribenzoate of tridimethylaminomethylphenol, which may be used alone or in combination of two or more. In the present invention, the amount of these reaction accelerators added is as follows:
The amount is 0.05 to 5% by weight, preferably 0.1 to 3.5% by weight in the conductive resin composition of the present invention. The binder used in the present invention can be easily produced by stirring and mixing at room temperature or under heating if necessary. In order to prevent thermal polymerization during production and dark reactions during storage, hydroquinone, hydroquinone monomethyl ether, 1-butyl-catechol,
It is desirable to add a known thermal polymerization inhibitor such as p-benzoquinone, 2,5-t-butyl-hydroquinone, or phenothiazine. The amount added is based on the photopolymerizable compound [(C) or (C) + (D)] of the present invention.
0.001-0.1% by weight, preferably 0.001-0.05
Weight%. The organic titanate compound (F) used in the present invention is
It has the chemical formula of Ti(OR) ₄ or Ti( _OR ) ₄ ate group, alkylpyrophosphate group,
An aryl pyrophosphate group, an alkyl sulfoyl group, an aryl sulfoyl group, or a functional group thereof having a substituent. Further, X is a compound having a coordinate bond to the titanium atom of the titanate, and examples thereof include phosphorous acid monoester, phosphorous acid diester, phosphorous acid triester, and the like. Typical compounds include tetraisopropyl titanate, tetra-n-butyl titanate, tetra (2-ethylhexyl) titanate, tetra (2-ethyl-3-hydroxyhexyl) titanate, tetra (8-hydroxyoctyl) titanate, dipropyl di( 1-methyl-3-keto-1
-butenyl) titanate, dibutyl di(8-hydroxyoctyl) titanate, dipropyl di(1
-Methyl-3-keto-1-pentenyl) titanate, dipropyl di(1-carboxyethyl) titanate, dipropyl di[2-(N,N-di-2-
hydroxyethyl) aminoethyl] titanate,
Tetraalkyl ester type titanate compounds such as dibutyldi[2-(N,N-di-2-hydroxyethyl)aminoethyl]titanate, isopropyltri(N-aminoethylaminoethyl)titanate, isopropyltri(tetraethylenetriamino)titanate dialkyl titanate compounds such as di(1-carboxyethyl) titanate, di(1-ammonium carboxyethyl) titanate, isopropyl tricumyl phenyl titanate,
Alkylaryl titanate compounds such as butyl tricumyl phenyl titanate, tetrastearoyl titanate, tri-n-butyl stearoyl titanate, isophenyl triisostearoyl titanate, isopropyl di(p-aminobenzoyl) isostearoyl titanate, isopropyl tri(o-amino) benzoyl) titanate, isopropyl tri(3-mercaptopropionyl) titanate, diisostearoyl ethylene titanate, isopropyl triricinoyl titanate, titanium di(cumyl phenylate) oxyacetate, isopropyl methacroyl diisostearoyl titanate, isopropyl dimethacroyl isostearoyl titanate, isopropyl diacryloyl isostearoyl titanate, isopropyl trimetacroyl titanate, isopropyl triacroyl titanate, titanium isostearate methacrylate oxyacetate, titanium isostearate acrylate oxyacetate, titanium dimethacrylate oxyacetate, titanium acrylate oxyacetate, etc. Carboxylic acid ester titanate compounds, isopropyl tridodecylbenzenesulfonyl titanate, isopropyl-4-aminobenzenesulfonyl di(dodecylbenzenesulfonyl) titanate, p-aminobenzenesulfonyldodecylbenzenesulfonyl ethylene titanate, etc. Sulfonic acid ester titanate compounds, isopropyl tri(dioctyl phosphate)
Phosphate ester type titanate compounds such as titanate, titanium di(dioctyl phosphate) oxyacetate, di(dioctyl phosphate) ethylene titanate, isopropyl tri(dioctyl pyrophosphate) titanate, isopropyl tri(butyloctyl pyrophosphate) titanate , isopropyl di(butyl methyl pyrophosphate) titanate mono(dioctyl hydrogen) phosphite, titanium di(dioctyl pyrophosphate) oxyacetate, titanium di(butyl octyl pyrophosphate) oxyacetate, di(dioctyl pyrophosphate) ethylene titanate , pyrophosphate ester titanate compounds such as di(butylmethylpyrophosphate) ethylene titanate, tetraisopropyl di(tridecyl phosphite) titanate, tetraisopropyl di(dioctyl phosphite) titanate, tetraoctyl di(ditridecyl phosphite) For example, triethylamine, diethylamine, N,N-dimethylaminoethanol, N,N
Examples include pyrophosphate titanate compounds obtained by reacting amines such as -diethylaminoethanol, 2-dimethylamino-2-methyl-1-propanol, and 2-dimethylaminopropyl (meth)acrylamide. These organic titanate compounds may be used alone or in combination of two or more. Among these, particularly desirable compounds are phosphoric acid or pyrophosphate titanate compounds. The amount of the organic titanate compound (F) used in the present invention is 0.05 to 10% by weight, preferably 0.1 to 3% by weight, particularly preferably 0.3 to 2% by weight of the conductive resin composition of the present invention. be. If the amount added is less than 0.05% by weight, the effect of improving adhesion will not appear.
If it exceeds 10% by weight, practical hardness cannot be obtained after thermosetting and the conductivity decreases. The method for curing the conductive resin composition of the present invention is to first cure the photopolymerizable compound (C) having a carboxyl group by irradiation with actinic rays such as ultraviolet rays, or to cure the photopolymerizable compound (C) and other photopolymerizable compounds. polymerize the mixture with the compound (D) to form a carboxyl group-containing polymer,
A two-step method is generally used, in which the material is then heated to react with the epoxy compound (B) and completely cured. Photopolymerization reaction conditions include light intensity of 20 mW/cm ² ~
The time ranges from 0.1 seconds to 15 minutes at 200 mW/cm ² . The thermosetting reaction conditions are a temperature of 50°C to 160°C and a time of 10 seconds to 120 minutes. The conductive resin composition of the present invention is irradiated with active light such as ultraviolet rays to induce a photopolymerization reaction. As light sources used for ultraviolet irradiation, sunlight, chemical lamps, low pressure mercury lamps, high pressure mercury lamps, carbon arc lamps, xenon lamps, metal halide lamps, etc. are used. A photoinitiator is not necessarily required when irradiating with an electron beam. The following points can be mentioned as excellent effects of the conductive resin composition of the present invention. (1) The epoxy compound (B) and the photopolymerizable compound [(C) or a mixture of (C) and (D)] have good compatibility, and the viscosity of the binder can be adjusted freely, making them conductive fine powders. Excellent mixability with (A). (2) The curing method uses a combination of active light curing such as ultraviolet rays and heat curing, so a completely cured and stable final cured product can be obtained and exhibits stable and good electrical conductivity. (3) It can be cured at lower temperatures and in a shorter time than conventional thermosetting conductive resin compositions. (4) Since the first stage of curing is performed by irradiating actinic light such as ultraviolet rays, preform can be formed in a few seconds to several tens of seconds, allowing temporary curing of printed materials, coated materials, and adhesive materials in a short time. It is possible to make it easier to handle by temporarily adhering it. (5) The obtained final cured product has excellent adhesion to the base material and flexibility. The conductive resin composition of the present invention takes advantage of the above-mentioned advantages and can be used to form conductive circuits on insulating substrates, bond chip parts, bond between contacts, bond lead wires, conductor portions of hybrid integrated circuit boards, resistors, etc. electrode terminal parts,
It can be used for a wide variety of purposes such as radio wave shielding. Examples are given below to explain the present invention more specifically, but the present invention is of course not limited to these Examples in any way. In addition, parts in the examples mean parts by weight. The viscosity, adhesiveness, flexibility, and specific resistance were measured according to the following methods. Viscosity: Measured at 25°C using Bruckfield viscosity. Adhesiveness: Measured by the cellophane tape peeling test method. Flexibility: The number of times the conductive resin composition was cured using an MIT tester specified in JIS P-8115 until it lost its conductivity was measured. Specific resistance: The resistance value of the cured conductive resin composition was measured using a Wheatstone bridge, and the specific resistance was calculated. Example 1 Bisphenol A type epoxy compound Epicote
1001 (manufactured by Yuka Ciel Epoxy), 54 parts of succinic acid monoacryloyloxyethyl ester, and 39 parts of tetrahydrofurfuryl acrylate were stirred and mixed at room temperature to obtain a colorless and transparent binder (). The resulting binder had a viscosity of 7.8 poise at 25°C. Scaly silver powder AgC-A (manufactured by Fukuda Metal Foil and Powder Industries)
70 parts Binder () 23 parts 2-hydroxy-2-methylpropiophenone
5 parts acrylic leveling agent 2 parts 2-(N,N-diethylamino)ethanol
0.5 parts titanium di(dioctylpyrophosphate)
Oxyacetate 1 part The above raw materials were thoroughly kneaded using three ceramic rolls to prepare a conductive resin composition. Using the obtained conductive resin composition, a 4.5 cm long, 2.5 cm wide, and 20 μm thick print was printed on the three types of substrates listed in Table 1 using a 300-mesh polyester screen plate. Under KW high pressure mercury lamp, 15cm
Ultraviolet light was irradiated for 40 seconds at a distance of . I tried gently rubbing the surface of the resulting cured product with my fingertips, but
There were no scratch marks on the painted surface. Prints cured by ultraviolet rays are placed in a hot air dryer.
Heating was performed at 120°C for 15 minutes to obtain a cured printed matter (a). Table 1 shows the measurement results of adhesiveness and specific resistance. When examining the flexibility of cured prints printed on 125μ corona-treated polyester film,
Continuity was lost after 190 cycles. Example 2 Scaly silver powder (as mentioned above) 80 parts Binder () 13 parts 2-hydroxy-2-methylpropiophenone
5 parts acrylic leveling agent 2 parts 2-(N,N-diethylamino)ethanol
0.5 part di(dioctyl pyrophosphate) ethylene titanate 1 part A conductive resin composition was obtained in the same manner as in Example 1, printed on three types of substrates, and cured printed matter (b) was obtained by heating and curing after irradiation with ultraviolet rays. Ta. Table 1 shows the measurement results of adhesiveness and specific resistance. Example 3 Bisphenol A type epoxy compound Epicoat
1004 (manufactured by Yuka Ciel Epoxy) 160 parts, 58 parts of succinic acid mono(1-methacroyloxymethyl) acroyloxyethyl ester, and 156 parts of tetrahydrofurfuryl acrylate were stirred and mixed at room temperature to create a colorless and transparent binder (). I got it. The resulting binder had a viscosity of 36.4 poise at 25°C. Scaly silver powder (as above) 70 parts Binder (23 parts) 2-hydroxy-methylpropiophenone 5 parts Acrylic leveling agent 2 parts 2-(N,N-diethylamino)ethanol
0.5 parts titanium di(dioctylpyrophosphate)
Oxyacetate 1 part After obtaining a conductive resin composition in the same manner as in Example 1, it was printed on three types of substrates, and cured printed matter (c) was obtained by heat curing after irradiation with ultraviolet rays. Table 1 shows the measurement results of adhesiveness and specific resistance. Comparative Example 1 Scaly silver powder (as above) 70 parts Binder (23 parts) 2-hydroxy-methylpropiophenone 5 parts Acrylic leveling agent 2 parts 2-(N,N-diethylamino)ethanol
0.5 part After obtaining a conductive resin composition in the same manner as in Example 1, it was printed on three types of substrates, and cured printed matter (d) was obtained by heating and curing after irradiation with ultraviolet rays. Table 1 shows the measurement results of adhesiveness and specific resistance. Comparative Example 2 Scaly silver powder (as above) 70 parts Binder (23 parts) 2-hydroxy-2-methylpropiophenone
5 parts acrylic leveling agent 2 parts 2-(N,N-diethylamino)ethanol
0.5 part After obtaining a conductive resin composition in the same manner as in Example 1, it was printed on three types of substrates, and cured printed matter (e) was obtained by heating and curing after irradiation with ultraviolet rays. Table 1 shows the measurement results of adhesiveness and specific resistance. Comparative Example 3 Scaly silver powder (as above) 70 parts Binder (23 parts) 2-hydroxy-2-methylpropiophenone
5 parts acrylic leveling agent 2 parts 2-(N,N-diethylamino)ethanol
0.5 part N-(2-aminoethyl)-3-aminopropyltrimethoxysilane 1 part A conductive resin composition was obtained in the same manner as in Example 1, but it solidified and could not be evaluated. Comparative Example 4 Scaly silver powder (as above) 70 parts Binder (23 parts) 2-hydroxy-2-methylpropiophenone
5 parts acrylic leveling agent 2 parts 2-(N,N-diethylamino)ethanol
0.5 parts 3-glycidyloxypropyltrimethoxysilane 1 part A conductive resin composition was obtained in the same manner as in Example 1, printed on three types of substrates (listed in Table 1), and cured by heating and curing after UV irradiation. I got (f). Table 1 shows the measurement results of adhesiveness and specific resistance. Comparative Example 5 Scaly silver powder (previously) 70 parts Binder (23 parts) 2-hydroxy-2-methylpropiophenone
5 parts acrylic leveling agent 2 parts 2-(N,N-diethylamino)ethanol
0.5 parts 3-Methacroyloxypropyltrimethoxysilane 1 part A conductive resin composition was obtained in the same manner as in Example 1, printed on three types of substrates, and cured by heating after irradiation with ultraviolet rays to obtain a cured product (g). Ta. Table 1 shows the measurement results of the adhesiveness and specific resistance. 【table】

Claims (1)

[Claims] 1. Conductive fine powder (A), epoxy compound (B) having at least two epoxy groups in the molecule, photopolymerizable compound (C) having carboxyl group in the molecule, or said compound ( A mixture of C) and another photopolymerizable compound (D),
A conductive resin composition comprising a photoinitiator (E) and an organic titanate compound (F). 2. The conductive resin composition according to claim 1, which contains a reaction promoter between an epoxy group and a carboxyl group.