JP2015110759A - Conductive adhesive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conductive adhesive comprising: an organic polymer having crosslinkable silicon groups; and metal particles having crystals grown, wherein the shape of the metal particles after growth of the crystals is such that a plurality of rod-shaped and/or scaly small pieces are mutually bonded, and not generating firmness in the adhesive during storage thereof.SOLUTION: Provided is a one component-type conductive adhesive comprising (A) 100 pts.mass of an organic polymer having silicon-containing groups containing hydrolyzable groups bonded to silicon atoms and capable of crosslinking by forming siloxane bonds; (B) metal particles having crystals grown, wherein the shape of the metal particles after growth of the crystals is such that a plurality of rod-shaped and/or scaly small pieces are mutually bonded; (C) scaly conductive metal particles formed of individual scales, and (D) 0.1 to 20 pts.mass of a silanol condensation catalyst. A mass ratio of the (B) component to the (C) component, (B)/(C), is 0.3 or more and 3 or less, and a total amount of the (B) component and the (C) component is 65 mass% or more and 85% or less of the conductive adhesive except volatile components.

Description

  The present invention relates to an organic polymer having a hydrolyzable group bonded to a silicon atom and having a silicon-containing group that can be cross-linked by forming a siloxane bond, and a conductive adhesive containing conductive particles. Hereinafter, a silicon-containing group that has a hydrolyzable group bonded to a silicon atom and can be cross-linked by forming a siloxane bond is also referred to as a cross-linkable silicon group.

  The organic polymer having a crosslinkable silicon group can be liquefied at room temperature and crosslinks at room temperature by the action of moisture such as moisture in the air to produce a cured product such as rubber. For this reason, it is used as a moisture curable adhesive. When used as an adhesive, prepare an adhesive by adding additives such as curing catalysts, fillers and dehydrating agents to organic polymers having crosslinkable silicon groups, so that they do not come into contact with moisture, cans, tubes Alternatively, it is often used as a one-component adhesive that is hermetically stored in a container such as a syringe. If it is not sealed, the organic polymer having a bridging silicon group is crosslinked by moisture in the air, resulting in a problem that the viscosity is increased or the film is completely cured. In use, when the adhesive in the sealed container is applied to a necessary portion, it is cured by moisture in the air and functions as an adhesive.

  Patent Documents 1 to 4 disclose a conductive adhesive containing an organic polymer having a crosslinkable silicon group and conductive metal particles such as silver particles as conductive particles. This adhesive has the advantage of curing at room temperature and can be used as an electronic circuit formation or as a substitute for solder.

  Patent Document 5 includes, as conductive metal particles having high conductivity even in a state of being blended in a resin, a radially extending convex portion and a concave portion in a gap between the convex portions, and an adjacent conductive layer. A conductive metal powder is disclosed in which a conductive path is formed by fitting and connecting the convex portion and the concave portion to each other between the powders. An example of such particles is the chestnut-shaped particles shown in FIG. Patent Document 6 discloses dendritic (dendritic) silver-coated copper particles as conductive metal particles having high conductivity. FIG. 2 of Patent Document 6 shows an example of such particles.

  The conductive metal particles disclosed in Patent Document 5 and Patent Document 6 are chestnut-shaped particles, dendritic particles, and the like, and such metal particles are easily in contact with each other, and are in electrical contact between the particles as compared with spherical particles. Therefore, it is estimated that high conductivity is exhibited.

  However, conductive adhesives in which such metal particles are blended with organic polymers having crosslinkable silicon groups are sealed in containers such as cans, tubes or syringes so that they do not come into contact with moisture as a one-part adhesive. It has been found that when stored, the viscosity increases during storage, making it difficult to transfer from the can to the applicator or to push out from the tube or syringe.

  It was also found that when the viscosity-increased adhesive is stirred or kneaded again, it returns to the viscosity before the increase and is reversible. If the organic polymer having a crosslinkable silicon group is crosslinked, the viscosity is increased. However, when the viscosity is increased by crosslinking, the viscosity does not decrease even if the viscosity-increased adhesive is stirred or kneaded again. It is considered that the reversible viscosity increase that occurs when using chestnut-like or dendritic conductive particles is not an increase in viscosity due to crosslinking of an organic polymer having a crosslinkable silicon group. In order to distinguish between an increase in viscosity due to crosslinking of an organic polymer having a crosslinkable silicon group and an increase in viscosity that returns to the viscosity before the increase when stirring or kneading, the increase in viscosity that returns to the viscosity before the increase when stirring or kneading is described Then we call it “Shimamari”.

  When the stirrer is again stirred and kneaded, the viscosity returns to the viscosity before the increase, but an extra step is required, and it is difficult to stir and knead itself with an adhesive stored in a small syringe. Therefore, an adhesive that does not cause tightness is desirable.

JP 59-24750 A JP-A-3-217476 JP-A-5-81923 WO2012-086588 JP 2002-298654 A JP 2013-100592 A

  The problem to be solved by the present invention is that a conductive adhesive containing an organic polymer having a crosslinkable silicon group and conductive particles such as a chestnut-like or dendritic shape does not cause a jam during storage of the adhesive. It is to provide a conductive adhesive.

The above problem is solved by the following conductive adhesive. The present invention also relates to an electrical product using this adhesive.
(1) (A) 100 parts by mass of an organic polymer having a hydrolyzable group bonded to a silicon atom and having a silicon-containing group that can be crosslinked by forming a siloxane bond;
(B) Metal particles that have been crystal-grown and in which the shape after crystal growth is a shape in which a plurality of rod-like and / or scaly pieces are bonded to each other,
(C) A conductive adhesive containing scaly conductive metal particles composed of one piece of scale, and (D) 0.1 to 20 parts by mass of a silanol condensation catalyst, wherein (B) component and (C) component The mass ratio (B) / (C) is 0.3 or more and 3 or less, and the total amount of the component (B) and the component (C) is 65% by mass or more and 85% by mass in the conductive adhesive excluding the volatile component. One-component conductive adhesive that is:
(2) The conductive adhesive according to (1), wherein the conductive metal particles are silver particles or silver-coated particles.
(3) (A) An organic polymer having a hydrolyzable group bonded to a silicon atom and having a silicon-containing group that can be crosslinked by forming a siloxane bond is an oxyalkylene polymer (1) or ( The conductive adhesive as described in 2).
(4) The conductive adhesive according to any one of (1) to (3), which is used for forming an electronic circuit or bonding an electronic component.
(5) An electric product using the conductive adhesive of (4).

  The conductive adhesive of the present invention has an effect that no tightness occurs during storage.

It is a figure of the metal particle which has one hook-shaped main axis | shaft, and the some hook-shaped branch has branched from this main axis | shaft. It is a figure of a metal particle which has a plurality of bowl-shaped main axes and a plurality of bowl-shaped branches branch from the main axes. FIG. 3 is a diagram of metal particles in which a metal particle has one or more bowl-shaped main axes, a plurality of bowl-shaped branches branch from the main axis, and scaly pieces are bonded to the bowl-shaped branches. It is a figure of the metal particle which the crystal | crystallization of the bowl-shaped piece grows radially from one nucleus. It is a figure of the metal particle which the crystal | crystallization of the scale-like small piece grows radially from one nucleus.

  In the conductive adhesive of the present invention, the crosslinkable silicon group in the organic polymer of the component (A) has a hydrolyzable group bonded to a silicon atom, and is a group that can be crosslinked by forming a siloxane bond. As a representative example, the formula (1):

(In the formula, R ¹ represents an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, or R ² ₃ SiO— (Wherein R ² is an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, and an aralkyl group having 7 to 20 carbon atoms). When two or more R ¹ are present, they may be the same or different, X represents a hydrolyzable group, and when two or more X are present, they are the same. A may be 0, 1, 2 or 3, b may be 0, 1 or 2, and n formulas (2):

B in need not be the same. n shows the integer of 0-19. However, a + (sum of b) ≧ 1 is satisfied. ).

  The hydrolyzable group can be bonded to one silicon atom in the range of 1 to 3, and a + (sum of b) is preferably in the range of 1 to 5. When two or more hydrolyzable groups or hydroxyl groups are bonded to the crosslinkable silicon group, they may be the same or different.

The number of silicon atoms forming the crosslinkable silicon group may be one or two or more, but in the case of silicon atoms linked by a siloxane bond or the like, there may be about 20 silicon atoms.
Formula (3):

A crosslinkable silicon group represented by the formula (wherein R ¹ , X and a are the same as described above) is preferable from the viewpoint of easy availability. In the crosslinkable silicon group of the formula (3), a is preferably 2 or 3. When a is 3, the curing rate is higher than when a is 2.

Specific examples of R ¹ include an alkyl group such as a methyl group and an ethyl group, a cycloalkyl group such as a cyclohexyl group, an aryl group such as a phenyl group, an aralkyl group such as a benzyl group, and R ² ₃ SiO—. And triorganosiloxy group. Of these, a methyl group is preferred.

  It does not specifically limit as a hydrolysable group shown by said X, What is necessary is just a conventionally well-known hydrolysable group. Specific examples include a hydrogen atom, a halogen atom, an alkoxy group, an acyloxy group, a ketoximate group, an amino group, an amide group, an acid amide group, an aminooxy group, a mercapto group, and an alkenyloxy group. Among these, a hydrogen atom, an alkoxy group, an acyloxy group, a ketoximate group, an amino group, an amide group, an aminooxy group, a mercapto group, and an alkenyloxy group are preferable, and an alkoxy group, an amide group, and an aminooxy group are more preferable. An alkoxy group is particularly preferred from the viewpoint of mild hydrolysis and easy handling. Among the alkoxy groups, those having a smaller number of carbon atoms have higher reactivity, and the reactivity increases as the number of carbon atoms increases in the order of methoxy group> ethoxy group> propoxy group. Although it can be selected according to the purpose and application, a methoxy group or an ethoxy group is usually used. In the case of the crosslinkable silicon group represented by the formula (3), a is preferably 2 or more in consideration of curability.

Specific examples of the crosslinkable silicon group include trialkoxysilyl groups such as a trimethoxysilyl group and a triethoxysilyl group, dialkoxysilyl groups such as —Si (OR) ₃ , a methyldimethoxysilyl group, and a methyldiethoxysilyl group. Group, —SiR ¹ (OR) ₂ . Here, R ¹ is the same as described above, and R is an alkyl group such as a methyl group or an ethyl group.

  Further, the crosslinkable silicon group may be used alone or in combination of two or more. The crosslinkable silicon group can be present in the main chain, the side chain, or both. It is preferable that a crosslinkable silicon group is present at the end of the molecular chain from the viewpoint of excellent cured product properties such as tensile properties of the cured product.

  It is preferable that at least one, preferably 1.1 to 5, crosslinkable silicon groups are present in one molecule of the polymer. When the number of crosslinkable silicon groups contained in the molecule is less than one, the curability is insufficient, and when the number is too large, the network structure becomes too dense, and good mechanical properties are not exhibited. In particular, in the case of producing a so-called non-plastic compounding curable composition that does not contain a low molecular weight plasticizer having a molecular weight of 800 or less, such as a phthalate ester plasticizer, and a molecular weight of 1000 or less, a crosslinkable silicon group is used. Are present in an average of 1.1 to 1.5, more preferably 1.1 to 1.3 per molecule of polymer. In the case of a curable composition containing no plastic, it is preferable to use a linear polymer.

  The main chain skeleton of the organic polymer having a crosslinkable silicon group is not particularly limited, and those having various main chain skeletons can be used. Specifically, polyoxyalkylene heavy polymers such as polyoxyethylene, polyoxypropylene, polyoxybutylene, polyoxytetramethylene, polyoxyethylene-polyoxypropylene copolymer, polyoxypropylene-polyoxybutylene copolymer, etc. Copolymer: ethylene-propylene copolymer, saturated hydrocarbon polymer such as polyisobutylene, copolymer of isobutylene and isoprene, polychloroprene, polyisoprene, isoprene or butadiene and acrylonitrile and / or styrene. Hydrocarbon polymers such as polymers, polybutadiene, isoprene or copolymers of butadiene and acrylonitrile, and / or styrene, and hydrogenated polyolefin polymers obtained by hydrogenating these polyolefin polymers; Polyester polymers such as condensation polymers of polybasic acids such as dipic acid, terephthalic acid and succinic acid and polyhydric alcohols such as bisphenol A, ethylene glycol and neopentyl glycol, and ring-opening polymers of lactones; Nylon 6 by ring-opening polymerization of caprolactam, nylon 6.6 by condensation polymerization of hexamethylenediamine and adipic acid, nylon 6.10 by condensation polymerization of hexamethylenediamine and sebacic acid, nylon 11 by condensation polymerization of ε-aminoundecanoic acid , Nylon 12 by ring-opening polymerization of ε-aminolaurolactam, polyamide-based polymer such as copolymer nylon having two or more components among the above nylons; monomers such as ethyl acrylate and butyl acrylate, ion polymerization and radical polymerization Polyacrylic acid ester, ethyl Acrylic acid ester-based polymers such as acrylic acid ester copolymers of acrylic acid esters such as acrylate and butyl acrylate with vinyl acetate, acrylonitrile, methyl methacrylate, styrene, etc .; polymerizing vinyl monomers in the organic polymer Examples thereof include graft polymers obtained by the above; polysulfide polymers; polycarbonate polymers produced by condensation polymerization from bisphenol A and carbonyl chloride, diallyl phthalate polymers, and the like.

  Of the polymers having the main chain skeleton, polyester polymers, acrylate polymers, polyoxyalkylene polymers, saturated hydrocarbon polymers, polycarbonate polymers, and the like are preferable. In particular, it is easy to introduce a crosslinkable silicon group into the molecular chain end, is relatively low in viscosity and inexpensive, has a low glass transition temperature, and the resulting cured product has excellent cold resistance, heat resistance, and weather resistance. Further, an alkyl acrylate polymer having excellent adhesion and a saturated hydrocarbon polymer having excellent electrical properties are preferred.

  Furthermore, since the mixture of the polyoxyalkylene polymer and the (meth) acrylic acid alkyl ester polymer is excellent in the mechanical strength of the cured product, and has excellent properties in heat resistance and adhesion to the substrate, It is particularly suitable for the present invention. When a mixture of an oxyalkylene polymer having a crosslinkable silicon group and a (meth) acrylic acid ester polymer having a crosslinkable silicon group is used, (meth) acrylic acid is used with respect to 100 parts by weight of the oxyalkylene polymer. The ester polymer is preferably used in an amount of 5 to 200 parts by weight, more preferably 5 to 50 parts by weight.

  The organic polymer having a crosslinkable silicon group may be linear or branched, and preferably has a number average molecular weight of about 500 to 50,000, more preferably 1,000 to 30,000. As the molecular weight increases, the hardness tends to decrease.

  Among the above polymers, the polyoxyalkylene polymer is essentially a polymer having a repeating unit represented by the formula (4).

(Wherein R ³ is a divalent organic group)
R ³ in Formula (4) is preferably a linear or branched alkylene group having 1 to 14 carbon atoms, and more preferably 2 to 4 carbon atoms. Specific examples of the repeating unit represented by the formula (4) include, for example,

Etc. The main chain skeleton of the polyoxyalkylene polymer may be composed of only one type of repeating unit, or may be composed of two or more types of repeating units. In particular, it is preferably made of a polymer mainly composed of oxypropylene.

  When a polyoxyalkylene polymer is used, its molecular weight is preferably larger because the tensile modulus, which is the tensile property of the cured product, is reduced and the elongation at break is increased. In the present invention, the lower limit of the number average molecular weight is preferably 5,000, and more preferably 10,000. Further, the upper limit of the number average molecular weight is preferably 50,000, and more preferably 30,000. In addition, the number average molecular weight as used in the field of this invention means the polystyrene conversion molecular weight by gel permeation chromatography. When the number average molecular weight is less than 5,000, the tensile modulus and elongation at break may not be sufficient. When the number average molecular weight exceeds 50,000, the viscosity of the composition may increase and workability may decrease.

  The polyoxyalkylene polymer may be linear or branched, but is preferably a linear polymer because the tensile modulus of the cured product can be reduced and the elongation at break can be increased. The molecular weight distribution of the polyoxyalkylene polymer having a crosslinkable silicon group is preferably 2 or less, particularly 1.6 or less.

  As a method for synthesizing a polyoxyalkylene polymer, for example, a polymerization method using an alkali catalyst such as KOH, for example, JP-A Nos. 61-197631, 61-215622, 61-215623, and 61-215623 can be used. Polymerization methods using an organoaluminum-porphyrin complex catalyst obtained by reacting an organoaluminum compound with porphyrin as shown, for example, double metal cyanide complexes shown in JP-B-46-27250 and JP-B-59-15336 Examples of the polymerization method using a catalyst include, but are not limited to, a polymerization method. According to the polymerization method using an organoaluminum-porphyrin complex catalyst or the polymerization method using a double metal cyanide complex catalyst, the number average molecular weight is 6,000 or more, and the Mw / Mn is 1.6 or less. Coalescence can be obtained.

  The main chain skeleton of the polyoxyalkylenes may contain other components such as a urethane bond component. Examples of the urethane bond component include aromatic polyisocyanates such as toluene (tolylene) diisocyanate, diphenylmethane diisocyanate and xylylene diisocyanate; aliphatic polyisocyanates such as isophorone diisocyanate and hexamethylene diisocyanate and polyoxyalkylenes having a hydroxyl group; What can be obtained from this reaction can be mentioned.

  The introduction of a crosslinkable silicon group into a polyoxyalkylene polymer can be performed on a polyoxyalkylene polymer having a functional group such as an unsaturated group, a hydroxyl group, an epoxy group or an isocyanate group in the molecule. The reaction can be carried out by reacting a compound having a reactive functional group and a crosslinkable silicon group. This method (hereinafter referred to as polymer reaction method) is also suitably used for polyester polymers, polyamide polymers, and polymers of unsaturated monomers obtained by living polymerization. This is because these polymers have a functional group such as a hydroxyl group at the end of the molecular chain, and therefore it is easy to introduce a crosslinkable silicon group at the end.

  As a specific example of the polymer reaction method, a hydrosilane or mercapto compound is produced by reacting an unsaturated group-containing oxyalkylene polymer with a hydrosilane having a crosslinkable silicon group or a mercapto compound having a crosslinkable silicon group to form a crosslinkable silicon group. The method of obtaining the oxyalkylene type polymer which has is mentioned. An unsaturated group-containing oxyalkylene polymer is an organic compound having an active group and an unsaturated group that are reactive with an organic polymer having a functional group such as a hydroxyl group, such as an unsaturated halogen compound. To give an oxyalkylene polymer containing an unsaturated group.

  Other specific examples of the polymer reaction method include a method of reacting an oxyalkylene polymer having a hydroxyl group at a terminal with a compound having an isocyanate group and a crosslinkable silicon group, or an oxyalkylene polymer having an isocyanate group at a terminal. And a method of reacting a compound having an active hydrogen group such as a hydroxyl group or an amino group and a crosslinkable silicon group. When an isocyanate compound is used, an oxyalkylene polymer having a crosslinkable silicon group can be easily obtained. The polymer reaction method can be applied to polymers other than oxyalkylene polymers.

  Specific examples of the oxyalkylene polymer having a crosslinkable silicon group include JP-B Nos. 45-36319 and 46-12154, JP-A Nos. 50-156599, 54-6096, and 55-13767. No. 57-164123, Japanese Patent Publication No. 3-2450, Japanese Patent Application Laid-Open No. 2005-213446, No. 2005-306891, International Publication No. WO 2007-040143, US Pat. Nos. 3,632,557, 4,345,053, The ones proposed in the publications such as 4,960,844 can be mentioned.

  The (meth) acrylic acid alkyl ester polymer having a crosslinkable silicon group is essentially a polymer having a repeating unit represented by the formula (5).

(Wherein R ⁴ represents a hydrogen atom or a methyl group, and R ⁵ represents an alkyl group)
R ⁵ in Formula (5) is an alkyl group, and an alkyl group having 1 to 30 carbon atoms is preferable. R ⁵ may be linear or branched. Moreover, the substituted alkyl group which has a halogen atom, a phenyl group, etc. may be sufficient. Examples of R ⁵ include methyl, ethyl, propyl, n-butyl, t-butyl, 2-ethylhexyl, lauryl, tridecyl, cetyl, stearyl, behenyl, glycidyl, etc. Examples thereof include an amino group-substituted alkyl group such as an epoxy group-substituted alkyl group and a diethylaminoethyl group.

  The molecular chain of the (meth) acrylic acid alkyl ester polymer consists essentially of the monomer unit of the formula (5), and the term “essentially” as used herein means that of the formula (5) present in the polymer. It means that the total of monomer units exceeds 50% by weight. The total of the monomer units of the formula (5) is preferably 70% by weight or more.

  Examples of monomer units other than formula (5) include (meth) acrylic acid such as acrylic acid and methacrylic acid; amide groups such as acrylamide, methacrylamide, N-methylolacrylamide, N-methylolmethacrylamide, and aminoethyl Monomers containing amino groups such as vinyl ether; and other monomer units derived from acrylonitrile, styrene, α-methylstyrene, alkyl vinyl ether, vinyl chloride, vinyl acetate, vinyl propionate, ethylene and the like.

  As described above, the (meth) acrylic acid alkyl ester polymer having a crosslinkable silicon group may be used in combination with an oxyalkylene polymer. In this case, in terms of high compatibility with the oxyalkylene polymer having a crosslinkable silicon group, the molecular chain having a crosslinkable silicon group has the following formula (6):

(Wherein R ⁴ is the same as above, R ⁶ is an alkyl group having 1 to 5 carbon atoms) and a (meth) acrylate monomer unit represented by the following formula (7):

A copolymer composed of a (meth) acrylic acid ester monomer unit represented by the formula (wherein R ⁴ is the same as above, and R ⁷ is an alkyl group having 6 or more carbon atoms) is preferred.

As R < ⁶ > of the said Formula (6), C1-C5, such as a methyl group, an ethyl group, a propyl group, n-butyl group, t-butyl group, etc., Preferably it is 1-4, More preferably, it is 1-2. Of the alkyl group. Incidentally, R ⁶ may be a kind, or may be a mixture of two or more.

R ^{7 in the} above formula (7) is, for example, 2-ethylhexyl group, lauryl group, tridecyl group, cetyl group, stearyl group, behenyl group and the like having 6 or more carbon atoms, usually 7-30, preferably 8-20. Long chain alkyl groups. R ⁷ may be a single type or a mixture of two or more types. Moreover, the weight ratio of the monomer unit of the formula (6) and the monomer unit of the formula (7) is preferably 95: 5 to 40:60, and more preferably 90:10 to 60:40.

  The (meth) acrylic acid alkyl ester polymer having a crosslinkable silicon group can usually be obtained by radical copolymerization of a (meth) acrylic acid alkyl ester and a (meth) acrylic acid alkyl ester having a crosslinkable silicon group. . Further, when an initiator having a crosslinkable silicon group or a chain transfer agent having a crosslinkable silicon group is used, the crosslinkable silicon group can be introduced into the molecular chain terminal.

  JP 2001-040037 A, JP 2003-048923 A and JP 2003-048924 A have a crosslinkable silicon group (meth) obtained by using a mercaptan having a crosslinkable silicon group and a metallocene compound. Acrylic acid alkyl ester polymers are described. Moreover, the synthesis example of Unexamined-Japanese-Patent No. 2005-026881 describes the (meth) acrylic-acid alkylester type polymer which has a crosslinkable silicon group by high temperature continuous polymerization.

  As disclosed in JP-A-2000-086999, a (meth) acrylic acid alkyl ester-based polymer having a crosslinkable silicon group, in which a crosslinkable silicon group is introduced at a high ratio at the molecular chain terminal, Are known. Since such a polymer is produced by living radical polymerization, a crosslinkable silicon group can be introduced into the molecular chain terminal at a high rate. In the present invention, a (meth) acrylic acid alkyl ester polymer as described above can be used.

  Specific examples of a (meth) acrylic acid ester-based polymer having a crosslinkable silicon group and a mixture of this polymer and an oxyalkylene polymer having a crosslinkable silicon group are disclosed in JP-A Nos. 59-122541 and 63-112642. And in each publication such as JP-A-6-172631. JP-A-59-78223, JP-A-59-168014, JP-A-60-228516, JP-A-60-228517, etc. disclose oxyalkylene polymers having a crosslinkable silicon group. (Meth) acrylic acid ester-based monomer is polymerized in the presence of a mixture of an oxyalkylene polymer having a crosslinkable silicon group and a (meth) acrylic acid alkyl ester polymer having a crosslinkable silicon group. The method of obtaining is described.

  Among organic polymers, a saturated hydrocarbon polymer is a polymer that does not substantially contain a carbon-carbon unsaturated bond other than an aromatic ring, and the polymer that forms the skeleton thereof is (1) ethylene, propylene, Polymerize olefin compounds having 2 to 6 carbon atoms such as 1-butene and isobutylene as the main monomer, or (2) homopolymerize diene compounds such as butadiene and isoprene, or olefin compounds Can be obtained by a method such as hydrogenation, but isobutylene-based polymers and hydrogenated polybutadiene-based polymers can easily introduce a functional group at the terminal, easily control the molecular weight, and The number of terminal functional groups can be increased, and an isobutylene-based polymer is particularly preferable.

  Those whose main chain skeleton is a saturated hydrocarbon polymer have characteristics of excellent heat resistance, weather resistance, durability, and moisture barrier properties. In the isobutylene-based polymer, all of the monomer units may be formed from isobutylene units, or may be a copolymer with other monomers, but the repeating unit derived from isobutylene is 50 from the viewpoint of rubber properties. Those containing at least mass% are preferred, those containing at least 80 mass% are more preferred, and those containing from 90 to 99 mass% are particularly preferred.

  As a method for synthesizing a saturated hydrocarbon polymer, various polymerization methods have been reported so far, but in particular, many so-called living polymerizations have been developed in recent years. In the case of saturated hydrocarbon polymers, particularly isobutylene polymers, the inifer polymerization found by Kennedy et al. (JP Kennedy et al., J. Polymer Sci., Polymer Chem. Ed. 1997, 15, 2843) It is known that it can be easily produced by using it, it can be polymerized with a molecular weight of about 500 to 100,000 with a molecular weight distribution of 1.5 or less, and various functional groups can be introduced at the molecular ends.

  Examples of the method for producing a saturated hydrocarbon polymer having a crosslinkable silicon group include, for example, Mochikoku 4-69659, JP-B-7-108928, JP-A-63-254149, JP-A-64-22904, Although described in JP-A-1-197509, JP-A-2539445, JP-A-2873395, JP-A-7-53882 and the like, it is not particularly limited thereto.

  The above saturated hydrocarbon polymer having a crosslinkable silicon group may be used alone or in combination of two or more.

  The conductive metal particles of the component (B) used in the present invention are metal particles obtained by crystal growth, and the shape after the crystal growth is a metal particle having a plurality of rod-like and / or scale-like pieces bonded to each other It is. Hereinafter, the conductive metal particles of the component (B) are also simply referred to as uneven conductive particles. Here, the bowl-shaped piece includes a rod-shaped piece and a linear piece. The concavo-convex conductive particles of component (B) may be metal particles in which the metal particles have a single bowl-shaped main axis and a plurality of bowl-shaped branches branch from the main axis as shown in FIG. In this case, the bowl-shaped piece having a major axis of less than 2 μm is not counted as the number of pieces. This is because small pieces are considered to have a small effect on conductivity. The concavo-convex conductive particles of the component (B) may be metal particles in which the metal particles have a plurality of bowl-shaped main axes and a plurality of bowl-shaped branches branch from the main axes as shown in FIG.

  The concavo-convex conductive particles of component (B), as shown in FIG. 3, have metal rods having one or more bowl-shaped main axes, and a plurality of bowl-shaped branches branch from the main axis, and scaly small pieces are formed on the bowl-shaped branches. May be a metal particle bonded to each other. In this case, the sum of the number of main shafts, the number of branches, and the number of scaly pieces becomes the total number of pieces. The thickness of the main shaft is preferably 0.3 μm or more and 5.0 μm or less, and the length of the longest branch among the branches extending from the main shaft is preferably 0.6 μm or more and 10.0 μm or less.

  Further, the uneven conductive particles (B) may be metal particles in which ridge-like pieces are radially grown from one nucleus as shown in FIG. Further, as shown in FIG. 5, metal particles in which scaly pieces are radially grown from one nucleus may be used. The small piece, particularly the scaly piece, may be a small piece without a cut line, a small piece with a cut line, or a saw blade shaped piece. In addition, the shape in which the plurality of scales become one scale as a whole is not the shape of the concavo-convex conductive particles of the component (B).

  The number of small pieces in the concavo-convex conductive particles of one component (B) may be 2 or more, preferably 5 or more, and more preferably 10 or more. When the long diameter of the small piece is less than 2 μm, it is not calculated as the number of small pieces.

The particle size of the concavo-convex conductive particles of component (B) is 3.0 μm to 30.0 μm as the center particle size (D50), that is, the volume cumulative particle size D50 measured by a laser diffraction scattering type particle size distribution measuring device. Is preferred. When the particles are large as the conductive particles, the conductive particle network in the paste is reduced, which may reduce the conductive performance. Further, even if the particle diameter is too small, the conductive particle network is reduced, so that the conductive performance may be deteriorated. The central particle size (D50) is preferably 3.0 μm to 30.0 μm, more preferably 4.0 μm or more and 25.0 μm or less, and particularly preferably 20.0 μm or less. A tap density of 0.3 to 2.0 g / cm ³ is preferable. The BET specific surface area (SSA) is preferably 0.30 to 1.50 m ² / g. The tap density is a value measured by a method according to JISK5101-12-2.

  The concavo-convex conductive particles of component (B) are required to have a shape in which a plurality of bowl-like and / or scale-like pieces are bonded to each other after crystal growth. In the state where the primary particles are agglomerated rather than the shape after crystal growth, the shape in which a plurality of cocoon-like and / or scale-like pieces are bonded to each other is included in the uneven conductive particles of component (B) of the present invention is not. This is because in the state where the primary particles are aggregated, in the case where a plurality of cocoon-like and / or scale-like pieces are bonded to each other, such a shape is liable to be broken by a kneading operation or the like in the process of manufacturing the adhesive.

  As (B) component uneven conductive particles, silver particles or copper particles coated with silver are preferable. The coating method is preferably a displacement plating coating method. The uneven conductive particles (B) are described in Patent Document 5 and Patent Document 6. It is also sold as ACAX-2, ACAX-3 or ACBY-3 by Mitsui Mining & Smelting Co., Ltd.

  The scale-like conductive particles composed of one scale as the component (C) used in the present invention are also called scale-like or flaky conductive particles. The planar shape of the scale may be any shape such as a circle, an ellipse or a rectangle. Further, it may be a dumpling shape in which a plurality of circular or elliptical shapes are combined, but it is necessary to have a scaly shape as a whole. The flatness of the scale-like conductive particles is preferably such that the ratio of the average particle size of the particles to the average thickness (average particle size of particles / average thickness of particles) is preferably 5-1000, more preferably 10-500, 200 is particularly preferred. In addition, the flatness of the uneven conductive particles of the component (B) is preferably less than 5. The average diameter and average thickness mean the average of the particle diameters and thicknesses of 30 particles randomly extracted from particles observed with an electron microscope at an appropriate magnification, for example, about 1,000 times. The particle size is the interval when the projection image of the projection perpendicular to the plane is sandwiched between parallel lines in a certain direction when the particle is placed on a plane to be in a stable state, and the thickness is the most from the plane. It is the height to the high part.

Component (C) having a flaky conductive particle central particle size (D50) of 1 to 20 μm, a specific surface area of 0.1 to ⁵ m ² / g and a tap density of 1 to 10 g / cm ³ is preferable. The center particle size (D50) is preferably 1.0 to 10 μm, the specific surface area is preferably 0.1 to 1.5 m ² / g, and the tap density is preferably 1.0 to 7.0 g / cm ³ .

Further, as the scale-like conductive particles (C), a 10% particle diameter by a laser diffraction scattering type particle size distribution measuring method is D10, a 50% particle diameter is D50, a 90% particle diameter is D90, and a standard deviation of the particle diameter is SD. Then, it is preferable to use scaly conductive particles having SD / D50 of 0.5 or less and D90 / D10 of 4.0 or less. The scale-like conductive particles (C) preferably have a 50% particle diameter (D50) of 1.0 to 10.0 μm, a specific surface area of 0.3 to 1.5 m ² / g, and a tap density of 1.0 to 1.0. 7.0 g / cm ³ is preferred.

  In the present invention, a mixture having a mass ratio (B) / (C) = 30/60 to 95/5 of the uneven conductive particles (B) and the scale-like conductive particles (C) is used. If it is less than 30/60, the dendrite-like conductive particles (B) are few and the conductivity may be lowered, and if it exceeds 95/5, the dendrite-like conductive particles (B) are too much to be pasty (liquid). It may not be.

  Moreover, the total amount of the uneven conductive particles (B) and the scaly conductive particles (C) is 65% by mass or more and 85% by mass or less in the conductive adhesive excluding the volatile component. If the amount is less than 65% by mass, the conductivity may decrease, and if it exceeds 85% by mass, it may be difficult to obtain a fluid adhesive. Volatile components include solvents and diluents. Even reactive diluents or diluents that do not volatilize depending on the usage conditions are regarded as adhesive components. The adhesive of the present invention may contain conductive particles other than the uneven conductive particles (B) and the scale-like conductive particles (C).

  The silanol condensation catalyst as component (D) used in the present invention is a catalyst for crosslinking and curing the organic polymer having a crosslinkable silicon group as component (A). If the silanol condensation catalyst is not present in the conductive adhesive of the present invention, there will be no failure. Examples of silanol condensation catalysts include alkyl titanates, organosilicon titanates, bismuth tris 2-ethylhexoate, dibutyltin dilaurate, dibutyltin maleate, dibutyltin diacetate, dioctyltin didibasate, dioctyltin dilaurate , Metal salts of carboxylic acids such as dioctyltin maleate, dioctyltin diacetate, tin octylate, tin naphthenate, etc .: amine salts such as dibutylamine-2-ethylhexoate, and other acidic and basic catalysts Can give. Among these, an organic tin compound is preferable, a tetravalent tin compound is more preferable, and a dioctyltin compound which is a tetravalent tin compound such as dioctyltin diversate is particularly preferable. When using a silanol condensation catalyst, it is good to use normally in the range of 0.1-20 mass parts with respect to 100 mass parts of (A) component, Preferably it is the range of 0.2-10 mass parts.

  The conductive adhesive of the present invention further includes a filler, an adhesion imparting agent, a dehydrating agent, an antioxidant, a light stabilizer, a diluent, a plasticizer, a lubricant, a pigment, a foaming agent, an epoxy resin and an epoxy resin curing agent. An agent or the like can be added as necessary.

  Examples of fillers include reinforcing fillers such as fumed silica, precipitated silica, silicic anhydride and carbon black; calcium carbonate, magnesium carbonate, diatomaceous earth, calcined clay, clay, talc, hardened titanium, bentonite, organic bentonite Further, fillers such as ferric oxide, zinc oxide, activated zinc white, hydrogenated castor oil and shirasu balloon; and fibrous fillers such as asbestos, glass fibers and filaments can be used.

  When it is desired to obtain a cured product having high strength by using these fillers, mainly fumed silica, precipitated silica, anhydrous silicic acid, hydrous silicic acid and carbon black, surface-treated fine calcium carbonate, calcined clay, clay, Preferred results are obtained by using fillers selected from activated zinc white and the like. In addition, when it is desired to obtain a cured product having low strength and large elongation, a filler selected from titanium oxide, calcium carbonate, magnesium carbonate, talc, ferric oxide, zinc oxide, shirasu balloon, etc. is mainly used. Preferred results are obtained when used. Of course, these fillers may be used alone or in combination of two or more. When using a filler, it is good to use in the range of 1-300 mass parts normally with respect to 100 mass parts of (A) component, Preferably it is the range of 5-300 mass parts, More preferably, it is 5-250 mass parts. .

  The adhesion-imparting agent is for improving the adhesion to the substrate. Examples of the adhesion-imparting agent include a silane coupling agent, a titanium coupling agent, and an aluminum coupling agent, and a silane coupling agent is preferable. A silane coupling agent is a compound having a crosslinkable silicon group and another functional group.

  Examples of such silane compounds include vinylalkyl (1 to 4 carbon atoms) alkoxy (1 to 4 carbon atoms) silane (for example, vinyltrimethoxysilane, vinyltriethoxysilane, etc.), (meth) acryloyloxyalkyl (carbon number). 1-4) alkoxy (C1-C4) silane (e.g., [gamma] -methacryloxypropyltrimethoxysilane), alkyl (C1-C4) alkoxy (C1-C4) silane (e.g., methyltrimethoxysilane), Methyltriethoxysilane and the like), amino (1 to 4 in the molecule) alkyl (2 to 15 carbon atoms) alkoxy (1 to 4 carbon atoms) silane (for example, γ- (2-aminoethyl) aminopropyltrimethoxysilane, Aminopropyltrimethoxysilane, N-phenylaminopropylmethyldimethoxysilane, etc.), epoxy (molecule 1 to 4) alkyl (1 to 4 carbon atoms) alkoxy (1 to 4 carbon atoms) silane (for example, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane), mercapto ( Examples thereof include 1 to 4 in the molecule, alkyl (1 to 4 carbon atoms), alkoxy (1 to 4 carbon atoms) silane (for example, γ-mercaptopropyltrimethoxysilane) and the like.

  Among these, a silane coupling agent having an amino group and a crosslinkable silicon group (hereinafter also referred to as aminosilane) is preferable because it has a large effect of improving adhesiveness. Moreover, the alkoxysilane compound which reacts with water and produces | generates the amine compound which has at least 1 alkoxysilyl group in 1 molecule can be used like the ketiminosilane which ketiminized the amino group. Alkoxysilane compounds which react with water to produce amine compounds having at least one alkoxysilyl group in one molecule are KBE-9103 (manufactured by Shin-Etsu Chemical Co., Ltd.), Silaace S340 (manufactured by Chisso Corporation), Z -6860 (manufactured by Toray Dow Corning Co., Ltd.) and the like.

  0.1-20 mass parts is preferable based on 100 mass parts of organic polymers which have a crosslinkable silicon group of (A) component, and, as for the usage-amount of an adhesive provision agent, 1-10 mass parts is more preferable. These adhesiveness-imparting agents can be used in combination of two or more.

  The conductive adhesive of the present invention can further contain a dehydrating agent. The dehydrating agent prevents the (A) component organic polymer having a crosslinkable silicon group from being crosslinked during storage. A silicate can be mentioned as a dehydrating agent. For example, tetraalkoxysilane or a partially hydrolyzed condensate thereof may be mentioned. More specifically, tetramethoxysilane, tetraethoxysilane, ethoxytrimethoxysilane, dimethoxydiethoxysilane, methoxytriethoxysilane, tetra-n-propoxy Tetraalkoxysilanes (tetraalkyl silicates) such as silane, tetra-i-propoxysilane, tetra-n-butoxysilane, tetra-i-butoxysilane, tetra-t-butoxysilane, and partial hydrolysis condensates thereof Can be mentioned. The above-described silane coupling agent can be used as the dehydrating agent.

  Although there is no restriction | limiting in particular in the mixture ratio of a dehydrating agent, 0.1-50 mass parts is preferable with respect to 100 mass parts of (A) component, and 1-50 mass parts is more preferable. A water | moisture-content absorber may be used independently and may use 2 or more types together.

  Examples of the antioxidant include p-phenylenediamine-based antioxidants, amine-based antioxidants, hindered phenol-based antioxidants, and secondary antioxidants such as phosphorus-based antioxidants and sulfur-based antioxidants. It is done. Although the addition amount of antioxidant is not specifically limited, Preferably it is 0.1-10 mass parts with respect to 100 mass parts of (A) component, More preferably, it can be used in 0.5-5 mass parts.

  Various types of light stabilizers are known, and are described in, for example, “Antioxidant Handbook” issued by Taiseisha, “Degradation and Stabilization of Polymer Materials” (235-242) issued by CM Chemical Co., Ltd. Although various things are mentioned, it is not necessarily limited to these. Among the light stabilizers, ultraviolet absorbers are preferable, and specifically, Tinuvin P, Tinuvin 234, Tinuvin 320, Tinuvin 326, Tinuvin 327, Tinuvin 329, Tinuvin 213 (all of which are manufactured by Ciba Geigy Japan), etc. Examples include benzotriazole compounds, triazine compounds such as Tinuvin 1577, benzophenone compounds such as CHIMASSORB 81, and benzoate compounds such as Tinuvin 120 (manufactured by Ciba Geigy Japan).

  Further, hindered amine compounds are also preferable, and specific examples of such compounds include those described in JP-A-2006-274084, but are not limited thereto. Furthermore, since the combination of the ultraviolet absorber and the hindered amine compound may exhibit more effect, it is not particularly limited, but may be used in combination, and it is preferable to use in combination. The light stabilizer may be used in combination with the above-described antioxidant, and it is particularly preferable because the effect is further exhibited and the weather resistance may be improved. Tinuvin C353, Tinuvin B75 (all of which are manufactured by Ciba Geigy Japan, Inc.) in which a light stabilizer and an antioxidant are mixed in advance may be used.

  It is preferable that the usage-amount of a light stabilizer is the range of 0.1-10 mass parts with respect to 100 mass parts of (A) component. If it is less than 0.1 parts by mass, the effect of improving the weather resistance is small, and if it exceeds 10 parts by mass, there is no great difference in the effect, which is economically disadvantageous.

  Diluents include, for example, aromatic hydrocarbons such as toluene and xylene, aliphatic hydrocarbons such as hexane, heptane and octane, alicyclic hydrocarbons such as methylcyclohexane, and petroleum solvents from gasoline to kerosene fractions. Dimethyl adipate (DMA), 2,2,4-trimethyl-1,3-pentanediol diisobutyrate (TXIB), esters such as ethyl acetate and butyl acetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, methylcyclohexanone, etc. Ethers such as ketones, tetrahydrofuran, cellosolve acetate, butyl cellosolve acetate, N, N-dimethylformamide, N, N-dimethylacetamide, 1-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, etc. Of nitrogen-containing solvents It is below.

  When using a diluent, it is good to use in the range of 0.5-50 mass parts normally with respect to 100 mass parts of (A) component, Preferably it is 1-30 mass parts.

  Specific examples of the plasticizer include phthalic acid esters such as dioctyl phthalate, dibutyl phthalate and butyl benzyl phthalate; aliphatic dibasic acid esters such as dioctyl adipate, isodecyl succinate and dibutyl sebacate; diethylene glycol dibenzoate, penta Glycol esters such as erythritol ester; aliphatic esters such as butyl oleate and methyl acetylricinoleate; phosphate esters such as tricresyl phosphate, trioctyl phosphate and octyl diphenyl phosphate; dibasic acid and dihydric alcohol Polyester plasticizers such as polyesters; Polyethers such as polypropylene glycol and its derivatives; Hydrocarbon plastics such as paraffinic hydrocarbons, naphthenic hydrocarbons, and paraffin-naphthene mixed hydrocarbons S; chlorinated paraffins; low molecular weight acrylic ester polymer and the like. These plasticizers may be used alone or in combination of two or more. In particular, when an acrylic ester polymer is used, the weather resistance of the cured product can be improved.

  When using a plasticizer, it is good to use in the range of 10-300 mass parts normally with respect to 100 mass parts of (A) component, Preferably it is the range of 20-250 mass parts. When the amount of the plasticizer used is less than 10 parts by mass, the viscosity of the composition may be too high, and when it exceeds 300 parts by mass, the plasticizer may exude from the cured product. It is not preferable.

  Examples of the epoxy resin include compounds having two or more epoxy groups in the molecule. Examples of such compounds include epichlorohydrin-bisphenol A type epoxy resin, epichlorohydrin-bisphenol F type epoxy resin, flame retardant type epoxy resin such as glycidyl ether of tetrabromobisphenol A, novolac type epoxy resin, hydrogenated bisphenol A type epoxy resin, Bisphenol A propylene oxide adduct glycidyl ether type epoxy resin, p-oxybenzoic acid glycidyl ether ester type epoxy resin, m-aminophenol type epoxy resin, diaminodiphenylmethane type epoxy resin, urethane modified epoxy resin, various alicyclic epoxy resins N, N-diglycidylaniline, N, N-diglycidyl-o-toluidine, triglycidyl isocyanurate, polyalkylene glycol diglycidyl a Examples include glycidyl ethers of polyhydric alcohols such as glycerin, glycerin, etc., epoxidized products of unsaturated polymers such as hydantoin type epoxy resins, petroleum resins, etc., but are not limited to these and are generally used. Any epoxy resin can be used.

  When using an epoxy resin, the amount used is preferably in the range of 1 to 1000 parts by mass with respect to 100 parts by mass of the polymer (A) having a crosslinkable silicon group. A more preferable range is 2 to 500 parts by mass, further 5 to 300 parts by mass, and particularly 5 to 200 parts by mass.

  As the epoxy resin curing agent, one or a plurality of commercially available epoxy resin curing agents can be selected and used. Examples of such a curing agent include amines, acid anhydrides, imidazoles, and other curing agents.

  As amines, primary to tertiary amines can be used. Primary amines include aliphatic amines (diethylenetriamine, triethylenetetramine, tetraethylenepentamine, dipropylenetriamine, polymethylenediamine (trimethylhexamethylenediamine, polyetherdiamine, diethylaminopropylamine)), alicyclic amines (men Sendiamine), aliphatic amines containing aromatic rings (metaxylenediamine), aromatic amines (metaphenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, aromatic diamine eutectic mixture), 3,9-bis (3-aminopropyl) ) -2,4,8,10-tetraspiro [5,5] undecane) and modified amines (amine adducts, cyanoethylated polyamines). Examples of secondary and tertiary amines include linear secondary amines, linear tertiary amines, tetramethylguanidine, piperidine, pyridine, picoline, benzyldimethylamine, and 2- (dimethylaminomethyl) phenol.

  Acid anhydrides include aromatic anhydrides (phthalic anhydride, trimellitic anhydride, ethylene glycol bis (anhydrotrimellitate), glycerol tris (anhydrotrimellitate), pyromellitic anhydride, 3, 3 ', 4,4'-benzophenonetetracarboxylic anhydride), cycloaliphatic anhydride (maleic anhydride, succinic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, alkenyl anhydride Acid, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylcyclohexene tetracarboxylic acid anhydride), aliphatic acid anhydride, polycarboxylic acid anhydride, halogenated acid anhydride, and chloresidic acid anhydride.

  Examples of imidazoles include 2-methylimidazole, 2-ethyl-4methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenylimidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl-2- Methylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 2,4-diamino-6- [2-methylimidazolyl- (1)]-ethyl-S-triazine, quaternary salt (1-dodecyl-2 -Methyl-3-benzylimidazolium chloride), isocyanurate (2-phenylimidazolium isocyanurate), hydroxymethyl (2-phenyl-4-methyl-5-hydroxymethylimidazole), boron trifluoride-amine A complex can be exemplified.

  Other curing agents include polyamide resin (condensate of dimer acid and polyamine), dicyandiamide and its derivatives, (o-tolylbiguanide, α-2,5-dimethylbiguanide), organic acid hydrazide (succinic acid hydrazide, adipic acid) Hydrazide), derivatives with diaminomaleonitrile, melamine and its derivatives, amine imides, polyamine salts, oligomers: synthetic resin initial condensate (novolac phenol resin, novolac cresol resin), polyvinylphenol (poly-p-vinylphenol) Can be mentioned.

  In particular, it is preferable to use amines, and a resin composition having excellent curability can be obtained. In addition, a compound in which an amino group is ketiminated can be used. In this case, a one-component curable composition that does not cure during storage can be easily produced.

  When using an epoxy resin hardening | curing agent, it is preferable to use 5-200 mass parts with respect to 100 mass parts of epoxy resins. As the lubricant, pigment, or foaming agent, commercially available products can be used.

  The method for producing the conductive adhesive of the present invention is not particularly limited. For example, the conductive adhesive can be produced by blending a predetermined amount of a compounded substance and degassing and stirring. The conductive adhesive of the present invention can be a one-component type or a two-component type as required, and can be suitably used particularly as a one-component type. The conductive adhesive of the present invention can be cured at room temperature by moisture in the atmosphere, and is suitably used as a room temperature moisture curable adhesive. Also good. Moreover, it is preferable that the conductive adhesive of this invention does not contain the solvent whose flash point is less than 65 degreeC.

  The conductive adhesive of the present invention can be suitably used as a conductive adhesive that can be used for bonding electronic components in place of solder. It can also be used to form a conductive circuit of a printed board by screen printing or a photo resist method. When the conductive adhesive of the present invention is used, an electrical product that does not use solder can be manufactured at low cost.

  The present invention will be described more specifically with reference to the following examples. However, it is needless to say that these examples are shown by way of illustration and should not be construed in a limited manner.

(Synthesis Example 1)
A methanol solution of sodium methoxide (NaOMe) was added to polyoxypropylene diol to distill off the methanol, and allyl chloride was further added to convert the terminal hydroxyl group to an allyl group. Unreacted allyl chloride was removed by devolatilization under reduced pressure, and the resulting metal salt was extracted and removed with water to obtain polyoxypropylene having an allyl group at the terminal. To the obtained allyl group-terminated polyoxypropylene, an isopropanol solution of a platinum vinylsiloxane complex is added to react with trimethoxysilane, and the weight average molecular weight in terms of PPG (polypropylene glycol) is about 25,000, and 1.5 per molecule. Polyoxypropylene polymer A1 having a number of terminal trimethoxysilyl groups was obtained.

(Synthesis Example 2)
Add a methanol solution of sodium methoxide (NaOMe) to polyoxypropylene diol having a molecular weight smaller than that of the polyoxypropylene diol used in Synthesis Example 1 to distill off the methanol, and then add allyl chloride to remove the terminal hydroxyl group. Converted to the base. Unreacted allyl chloride was removed by devolatilization under reduced pressure, and the resulting metal salt was extracted and removed with water to obtain polyoxypropylene having an allyl group at the terminal. To the resulting allyl group-terminated polyoxypropylene, an isopropanol solution of a platinum vinylsiloxane complex is added and reacted with trimethoxysilane, so that the weight average molecular weight in terms of PPG is about 15000, and 1.5 terminal trioxyls per molecule. A polyoxypropylene polymer A2 having a methoxysilyl group was obtained.

(Synthesis Example 3)
In a flask, 40 parts by mass of ethyl acetate as a solvent, 59 parts by mass of methyl methacrylate, 25 parts by mass of 2-ethylhexyl methacrylate, 21 parts by mass of γ-methacryloxypropylmethyldimethoxysilane, and 0.1 part by mass of ruthenocene dichloride as a metal catalyst were added. The mixture was heated to 80 ° C. while introducing charged nitrogen gas. Next, 7.5 parts by mass of 3-mercaptopropylmethyldimethoxysilane was added to the flask and reacted at 80 ° C. for 6 hours. After cooling to room temperature, 20 parts by mass of a benzoquinone solution (95% THF solution) was added to terminate the polymerization. The solvent and unreacted substances are distilled off, and the weight average molecular weight in terms of polystyrene is about 6000, the Mw / Mn is 1.6, and the acrylate ester weight having a dimethoxysilyl group having a Tg of 61.2 ° C. Combined A3 was obtained.

Example 1
Oxypropylene having a crosslinkable silicon group obtained in Synthesis Example 1 in a flask equipped with a stirrer, a thermometer, a nitrogen inlet, a monomer charging tube, and a water-cooled condenser at the blending ratio (mass basis) shown in Table 1. Polymer A1, oxypropylene polymer A2 having a crosslinkable silicon group obtained in Synthesis Example 2, acrylic polymer A3 having a crosslinkable silicon group obtained in Synthesis Example 3, and unevenness of component (B) Conductive particles, scale-like conductive particles of component (C), fine silica as a filler, hindered phenol-based antioxidants and hindered amine-based antioxidants as antioxidants, hindered amine-based light stabilizers as light stabilizers, and Normal paraffin was mixed as a diluent. The mixture was kneaded and dehydrated by heating (100 ° C.), degassing and stirring for 2 hours. After cooling, 3-aminopropyltrimethoxysilane as an adhesion-imparting agent, vinyltrimethoxysilane and n-decyltrimethoxysilane as a dehydrating agent, and dioctyltin diversate as a silanol condensation catalyst are added to the mixture and mixed and stirred. A conductive adhesive was prepared.
This conductive adhesive was filled into a 10 ml polyethylene syringe (Clear Syringe PSY-10E, manufactured by Musashi Engineering Co., Ltd.), and further put in an aluminum bag for deaeration and sealing. Then, it was allowed to stand for 1 month in an atmosphere at 23 ° C. and 50% RH, and the tightness was evaluated. Moreover, the predetermined | prescribed evaluation sample was created and volume resistivity was evaluated.

(Comparative Example 1 and Comparative Example 2)
A conductive adhesive was prepared in the same manner as in Example 1 except that the scaly conductive particles were not blended, and the tightness and volume resistivity were evaluated. The method for evaluating the tightness and volume resistivity is as follows.

(Shimari)
A sample stored at 23 ° C. and 50% RH for one month was measured for a discharge pressure of 300 kPa and a discharge time of 2 seconds, and the weight discharged within a predetermined time. When the discharge amount was 70% or more of the discharge amount before storage, there was no tightness, and when it was less than 70%, there was a tightness. The equipment used is as follows.
Dispense controller: ML-80FX manufactured by Musashi Engineering Co., Ltd.
Nozzle: Made by Musashi Engineering Co., Ltd. Double thread taper nozzle TPND-18G Inner diameter 0.84mm

(Volume resistivity)
The conductive adhesive was stretched to a thickness of about 2OO μm using a spacer, and cured for 7 days at 23 ° C. and 50% RH to prepare a cured sheet. The body soaking resistivity was measured by a four-end needle method using Lorester MCP-T360 manufactured by Mitsubishi Chemical Corporation.

The addition amount in the composition of the table is shown in parts by mass, and details of the compounding substances are as follows.
* 1 Polymer A1 obtained in Synthesis Example 1, linear polymer having a number average molecular weight of 25000, a main chain structure of polyoxyalkylene, and having a trimethoxysilyl group as a crosslinkable silicon group * 2 Synthesis Polymer A2 obtained in Example 2, linear polymer having a number average molecular weight of 15000, a main chain structure substantially polyoxyalkylene, and having a trimethoxysilyl group as a crosslinkable silicon group * 3 Synthesis Polymer A3 obtained in Example 3, a polystyrene-equivalent weight average molecular weight of about 6000, Mw / Mn is 1.6, and Tg is 61.2 ° C. Acrylic ester-based heavy polymer having a dimethoxysilyl group Combined * 4 Made by Mitsui Mining & Smelting Co., Ltd., trade name: ACAX-3, silver-plated copper powder, and has a single spindle when observed using a scanning electron microscope (SEM). Or Dendritic conductive particles in which a plurality of branches are obliquely branched and crystal is grown three-dimensionally. The center particle size (D50) is 16.4 μm, the BET specific surface area (SSA) is 0.41 m ² / g, and the tap density is 1.05 g / cm ³ .
* 5 Made by Mitsui Mining & Smelting Co., Ltd., trade name: 1400 YP (10%), 1400 YP (copper powder) silver-plated copper powder silver-plated at a weight ratio of 10%, center particle size (D50) is 5.81 μm, standard Deviation (SD) is 2.74 μm, 10% particle size (D10) is 3.58 μm, 90% particle size (D90) is 9.03 μm, SD / D50 value is 0.47, and D90 / D10 value is 2.52. is there. The BET specific surface area (SSA) is 0.26 m ² / g, and the tap density is 4.3 g / cm ³ .
* 6 Product name: R972, manufactured by Nippon Aerosil Co., Ltd.
* 7 Product name: KBM-903, manufactured by Shin-Etsu Chemical Co., Ltd.
* 8 Product name: KBM-1003, manufactured by Shin-Etsu Chemical Co., Ltd.
* 9 Product name: 3103C, manufactured by Shin-Etsu Chemical Co., Ltd.
* 10 Product name: AO-60, manufactured by ADEKA Corporation
* 11 Product name: NOCRACK CD manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.
* 12 Product name: LA-63P, manufactured by ADEKA Corporation
* 13 Product name: U-830, manufactured by Nitto Kasei Kogyo Co., Ltd.
* 14 Product name: N-11, manufactured by JX Nippon Oil & Energy Corporation

Claims (5)

(A) 100 parts by mass of an organic polymer having a hydrolyzable group bonded to a silicon atom and having a silicon-containing group that can be crosslinked by forming a siloxane bond;
(B) Metal particles that have been crystal-grown and in which the shape after crystal growth is a shape in which a plurality of rod-like and / or scaly pieces are bonded to each other,
(C) A conductive adhesive containing scaly conductive metal particles composed of one piece of scale, and (D) 0.1 to 20 parts by mass of a silanol condensation catalyst, wherein (B) component and (C) component The mass ratio (B) / (C) is 0.3 or more and 3 or less, and the total amount of the component (B) and the component (C) is 65% by mass or more and 85% by mass in the conductive adhesive excluding the volatile component. One-component conductive adhesive that is:   The conductive adhesive according to claim 1, wherein the conductive metal particles are silver particles or silver-coated particles.   3. The organic polymer having (A) a hydrolyzable group bonded to a silicon atom and having a silicon-containing group that can be crosslinked by forming a siloxane bond is an oxyalkylene polymer. Conductive adhesive.   The conductive adhesive according to claim 1, wherein the conductive adhesive is used for forming an electronic circuit or bonding an electronic component. An electrical product using the conductive adhesive according to claim 4.

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