JPWO2012086588A1 - Conductive adhesive - Google Patents

Abstract

Provided is a conductive adhesive that has excellent conductivity and adhesiveness, can prevent sedimentation and bleeding, and has excellent conductivity stability. (A) The main chain skeleton is one or more selected from the group consisting of a polyoxyarlequin polymer, a saturated hydrocarbon polymer, and a (meth) acrylic ester polymer, and a crosslinkable silicon group (B) a first silver powder (b1) having a specific surface area of 0.5 m 2 / g or more and less than 2 m 2 / g and a tap density of 2.5 to 6.0 g / cm 3, and a specific surface area of 2 m 2 / G or more and 7 m2 / g or less, the silver powder containing the second silver powder (b2) having a tap density of 1.0 to 3.0 g / cm3 in a predetermined mixing ratio, and (C) hydrophobic by a specific surface treatment agent The conductive adhesive contains one or more types of silica selected from the group consisting of hydrophobized hydrophobic silica and hydrophilic silica.

Description

  The present invention relates to a conductive adhesive, and particularly relates to a conductive adhesive excellent in conductivity and adhesiveness.

Conventionally, metal powder such as silver powder or carbon black has been used as a conductive filler of an organic polymer having a crosslinkable silicon group (Patent Document 1). In recent years, conductive adhesives have been used for bonding of electronic components such as semiconductor elements and bonding of crystal resonators or piezoelectric elements. For such applications, the volume resistivity is 10 × 10 ⁻³ Ω · There is a need for materials with lower resistance values that are required to be less than cm.

As a conductive adhesive containing silver powder, Patent Document 2 discloses a conductive elastic material containing ground powder of flaky silver foil having an average particle size of 45 μm or more and 1000 μm obtained by grinding silver foil, and dendritic 50 μm silver powder. An adhesive is disclosed [Patent Document 2, Example (2)]. Further, Patent Document 3 discloses an appearance including a crumpled silver powder having an average particle diameter of 45 μm to 100 μm obtained by pulverizing a silver foil as a silver powder used in a polymer compound-based conductive adhesive having a reactive silicon group. discloses a bulky silver powder density ^{0.01g / cm 3 ~0.1g / cm 3} . However, each of the conductive adhesives described in Patent Documents 2 and 3 has a problem that the particle size of the silver powder is large and the resistance value is high or unstable.

Japanese Examined Patent Publication No. 4-56064 JP-A-3-217476 JP-A-5-81923

  An object of the present invention is to provide a conductive adhesive that has excellent conductivity and adhesiveness, can prevent sedimentation and bleeding, and has excellent conductivity stability.

  In order to solve the above-mentioned problems, the present inventors have conducted intensive studies. As a result, the present invention has a crosslinkable silicon group and the main chain skeleton is a polyoxyarlequin polymer, a saturated hydrocarbon polymer, and (meta ) Combined use of first and second silver powders having a predetermined specific surface area and tap density in one or more organic polymers selected from the group consisting of acrylate-based polymers, and a specific surface treatment agent It has been found that the above object can be achieved by using one or more types of silica selected from the group consisting of hydrophobic silica and hydrophilic silica that have been subjected to a hydrophobization treatment.

That is, in the conductive adhesive of the present invention, (A) the main chain skeleton is selected from the group consisting of a polyoxyarlequin polymer, a saturated hydrocarbon polymer, and a (meth) acrylate polymer. One or more organic polymers having a crosslinkable silicon group, (B) a silver powder containing the first silver powder (b1) and the second silver powder (b2), and (C) a surface treatment agent to make it hydrophobic A conductive adhesive containing at least one silica selected from the group consisting of hydrophobized hydrophobic silica and hydrophilic silica, wherein the specific surface area of the first silver powder (b1) is 0.5 m ² / g to less than 2 m ² / g, the tap density is 2.5 to 6.0 g / cm ³ , the specific surface area of the second silver powder (b2) is 2 m ² / g to 7 m ² / g, and the tap density is 1.0 to 3.0 g / cm ³ , and the mixture of (b1) and (b2) The ratio [(b1) / (b2)] is 1/10 to 10/1 by mass ratio, the (B) silver powder is 65% by mass to 85% by mass of the total content, and the surface treatment agent is , Dimethyldichlorosilane, hexamethyldisilazane, (meth) acrylsilane, octylsilane, and aminosilane.

  In the conductive adhesive of the present invention, it is preferable that Tg of the (meth) acrylic acid ester polymer is 10 to 180 ° C. in consideration of adhesiveness.

  The conductive adhesive of the present invention is suitably used for joining semiconductor elements, chip parts, discrete parts, or combinations thereof. Further, the conductive adhesive of the present invention is suitably used for bonding a crystal resonator or a piezoelectric element.

  The circuit of the present invention is characterized in that a semiconductor element, a chip component, a discrete component, or a combination thereof is bonded using the conductive adhesive of the present invention.

ADVANTAGE OF THE INVENTION According to this invention, it is excellent in electroconductivity and adhesiveness, can prevent sedimentation and bleeding, and can obtain the electroconductive adhesive excellent in electroconductivity stability. Moreover, according to this invention, it is also possible to obtain the conductive adhesive excellent in discharge property. The conductive adhesive of the present invention has high conductivity by being applied or printed on a substrate and cured, and can be used instead of solder. The conductive adhesive of the present invention can achieve a low resistance value of a volume resistivity of less than 10 × 10 ⁻³ Ω · cm, in particular, bonding of electronic components such as semiconductor elements, chip components, discrete components, It is suitably used for bonding a crystal resonator or a piezoelectric element.

  In addition, the conductive adhesive of the present invention has one or more main chain skeletons selected from the group consisting of polyoxyarlequin polymers, saturated hydrocarbon polymers, and (meth) acrylate polymers. Therefore, the glass transition temperature is relatively low, the resulting cured product is excellent in cold resistance, does not contain low-molecular cyclic siloxane, is free of siloxane, and can prevent contact failure. Has a tremendous effect. Further, the conductive adhesive of the present invention can be used without a solvent and lead-free, and has an effect of being environmentally friendly. Furthermore, since the conductive adhesive of the present invention is an elastic adhesive, it has an effect of being excellent in durability such as thermal shock.

  Embodiments of the present invention will be described below, but these are exemplarily shown, and it goes without saying that various modifications are possible without departing from the technical idea of the present invention.

  The conductive adhesive of the present invention is selected from the group consisting of (A) an organic polymer having a crosslinkable silicon group, (B) silver powder, and hydrophobic silica and hydrophilic silica that have been hydrophobized by a specific surface treatment agent. A conductive adhesive containing one or more selected silicas.

  The organic polymer (A) used in the conductive adhesive of the present invention has a crosslinkable silicon group, and the main chain skeleton is a polyoxyarlequin polymer, a saturated hydrocarbon polymer, and ( The organic polymer which is 1 or more types selected from the group which consists of a meth) acrylic-ester type polymer is used.

  The crosslinkable silicon group of the organic polymer (A) is a group having a hydroxyl group or a hydrolyzable group bonded to a silicon atom and capable of crosslinking by forming a siloxane bond. A representative example is a group represented by the following general formula (1).

In the general formula (1), R ¹ 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, an aralkyl group having 7 to 20 carbon atoms, or R ¹ ₃ SiO— (R ¹ is the same as above) represents a triorganosiloxy group, and when two or more R ¹ are present, they may be the same or different. X represents a hydroxyl group or a hydrolyzable group, and when two or more X exist, they may be the same or different. a represents 0, 1, 2, or 3, and b represents 0, 1, or 2, respectively. n shows the integer of 0-19. However, a + (sum of b) ≧ 1 is satisfied. Moreover, b in n following General formula (2) does not need to be the same.

The hydrolyzable group or hydroxyl 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.

  As the crosslinkable silicon group, a crosslinkable silicon group represented by the following general formula (3) is preferable because it is easily available.

In the general formula (3), R ¹ , X, and a are the same as described above.
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 ¹ 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 use, a methoxy group or an ethoxy group is usually used.

  In the case of the crosslinkable silicon group represented by the general formula (3), a is preferably 2 or more and more preferably a is 3 in view of curability.

Specific structures of the crosslinkable silicon group include trialkoxysilyl groups such as trimethoxysilyl group and triethoxysilyl group, dialkoxysilyl groups such as —Si (OR) ₃ , methyldimethoxysilyl group, and methyldiethoxysilyl group. Group, —SiR ¹ (OR) ₂ . Here, 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.
The number of silicon atoms forming the crosslinkable silicon group is one or more, but in the case of silicon atoms linked by a siloxane bond or the like, it is preferably 20 or less.

  The organic polymer having a crosslinkable silicon group may be linear or branched, and its number average molecular weight is about 500 to 100,000 in terms of polystyrene in GPC, more preferably 1,000 to 50,000. And particularly preferably 3,000 to 30,000. If the number average molecular weight is less than 500, the cured product tends to be disadvantageous in terms of elongation characteristics, and if it exceeds 100,000, the viscosity tends to be inconvenient because of high viscosity.

(A) The number of crosslinkable silicon groups contained in the organic polymer is not particularly limited, but in order to obtain a rubber-like cured product having high strength, high elongation, and low elastic modulus, the organic polymer 1 There should be at least one, preferably 1.1 to 5, on average in the molecule. If the number of crosslinkable silicon groups contained in the molecule is less than 1 on average, the curability becomes insufficient and it becomes difficult to exhibit good rubber elastic behavior.
The crosslinkable silicon group may be at the end of the main chain or the side chain of the organic polymer molecular chain, or at both ends. In particular, when the crosslinkable silicon group is only at the end of the main chain of the molecular chain, the effective network length of the organic polymer component contained in the finally formed cured product is increased, so that the strength and elongation are high. It becomes easy to obtain a rubber-like cured product exhibiting a low elastic modulus.

(A) The polyoxyarlequine polymer containing a crosslinkable silicon group used as the organic polymer is essentially a polymer having a repeating unit represented by the following general formula (4).
—R ² —O— (4)
In the general formula (4), R ² is a linear or branched alkylene group having 1 to 14 carbon atoms, and a linear or branched alkylene group having 1 to 14 carbon atoms, preferably 2 to 4 carbon atoms. Is preferred.

Specific examples of the repeating unit represented by the general formula (4) include, for example,
_{-CH 2 O -, - CH 2} CH 2 O -, - CH 2 CH (CH 3) O -, - CH 2 CH (C 2 H 5) O -, - CH 2 C (CH 3) 2 O-, _{-CH 2 CH 2 CH 2 CH 2} O-
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.

  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 method using an organoaluminum-porphyrin complex catalyst obtained by reacting an organoaluminum compound and a porphyrin as shown, for example, a double metal cyanide complex 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. A polyoxyalkylene system having a narrow molecular weight distribution with a high molecular weight having a number average molecular weight of 6,000 or more and Mw / Mn of 1.6 or less according to a polymerization method using an organic aluminum-porphyrin complex catalyst or a polymerization method using a double metal cyanide complex catalyst A polymer can be obtained.

  The main chain skeleton of the polyoxyalkylene polymer 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, xylylene diisocyanate; aliphatic polyisocyanates such as isophorone diisocyanate and hexamethylene diisocyanate; The thing obtained from reaction with coalescence can be mention | raise | lifted.

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 (hereinafter referred to as a polymer reaction method).
As a specific example of the polymer reaction method, a hydrosilane or mercapto compound obtained by allowing a hydrosilane having a crosslinkable silicon group or a mercapto compound having a crosslinkable silicon group to act on an unsaturated group-containing polyoxyalkylene polymer to form a crosslinkable silicon group The method of obtaining the polyoxyalkylene type polymer which has this can be mention | raise | lifted. An unsaturated group-containing polyoxyalkylene polymer is obtained by reacting an organic polymer having a functional group such as a hydroxyl group with an organic compound having an active group and an unsaturated group that are reactive with the functional group, A polyoxyalkylene polymer containing can be obtained.
Other specific examples of the polymer reaction method include a method of reacting a polyoxyalkylene polymer having a hydroxyl group at a terminal with a compound having an isocyanate group and a crosslinkable silicon group, or a polyoxyalkylene system having an isocyanate group at a terminal. Examples thereof include a method of reacting a polymer with 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, a polyoxyalkylene polymer having a crosslinkable silicon group can be easily obtained.

  Specific examples of the polyoxyalkylene polymer having a crosslinkable silicon group include JP-B Nos. 45-36319, 46-12154, JP-A Nos. 50-156599, 54-6096, and 55-13767. No. 57-164123, JP-B No. 3-2450, JP-A No. 2005-213446, No. 2005-306891, International Publication No. WO2007-040143, US Pat. No. 3,632,557, No. 4,345,053, The ones proposed in the publications such as 4,960,844 can be listed.

  The above polyoxyalkylene polymers having a crosslinkable silicon group may be used alone or in combination of two or more.

(A) The saturated hydrocarbon polymer containing a crosslinkable silicon group used as an organic polymer is a polymer that does not substantially contain a carbon-carbon unsaturated bond other than an aromatic ring, and is a heavy polymer that forms the skeleton. The coalescence may be (1) polymerized using a olefin compound having 2 to 6 carbon atoms such as ethylene, propylene, 1-butene, isobutylene or the like as a main monomer, or (2) a diene compound such as butadiene or isoprene. It can be obtained by homopolymerization or by copolymerization with the above olefinic compound, followed by hydrogenation. However, isobutylene-based polymers and hydrogenated polybutadiene-based polymers introduce functional groups at the ends. This is preferable because the molecular weight can be easily controlled and the number of terminal functional groups can be increased, and an isobutylene 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, Japanese Patent Publication No. 4-69659, Japanese Patent Publication No. 7-108928, Japanese Patent Publication No. 63-254149, Japanese Patent Publication No. 64-22904, Although described in each specification of Kaihei 1-197509, Japanese Patent Publication No. 2539445, Japanese Patent Publication No. 2873395, and Japanese Patent Application Laid-Open No. 7-53882, it is not particularly limited thereto.

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

(A) The (meth) acrylic acid ester monomer constituting the main chain of the (meth) acrylic acid ester polymer containing a crosslinkable silicon group used as the organic polymer is not particularly limited. Can be used. Examples include (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, Isobutyl (meth) acrylate, tert-butyl (meth) acrylate, n-pentyl (meth) acrylate, n-hexyl (meth) acrylate, cyclohexyl (meth) acrylate, n-heptyl (meth) acrylate, N-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, phenyl (meth) acrylate, (meth) acrylic Acid toluyl, benzyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, (meth) acrylic 3-methoxybutyl, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, stearyl (meth) acrylate, glycidyl (meth) acrylate, 2-aminoethyl (meth) acrylate, γ -(Methacryloyloxypropyl) trimethoxysilane, γ- (methacryloyloxypropyl) dimethoxymethylsilane, methacryloyloxymethyltrimethoxysilane, methacryloyloxymethyltriethoxysilane, methacryloyloxymethyldimethoxymethylsilane, methacryloyloxymethyldiethoxymethylsilane, (Meth) acrylic acid ethylene oxide adduct, (meth) acrylic acid trifluoromethyl methyl, (meth) acrylic acid 2-trifluoromethyl ethyl, (meth) acrylic acid 2- -Fluoroethylethyl, 2-perfluoroethyl-2-perfluorobutylethyl (meth) acrylate, perfluoroethyl (meth) acrylate, trifluoromethyl (meth) acrylate, bis (trifluoro) (meth) acrylate Methyl) methyl, (meth) acrylic acid 2-trifluoromethyl-2-perfluoroethylethyl, (meth) acrylic acid 2-perfluorohexylethyl, (meth) acrylic acid 2-perfluorodecylethyl, (meth) acrylic Examples include (meth) acrylic acid monomers such as 2-perfluorohexadecylethyl acid.

  In the (meth) acrylic acid ester polymer, the following vinyl monomer can be copolymerized together with the (meth) acrylic acid ester monomer. Examples of the vinyl monomer include styrene monomers such as styrene, vinyl toluene, α-methyl styrene, chlorostyrene, styrene sulfonic acid, and salts thereof; fluorine-containing vinyl monomers such as perfluoroethylene, perfluoropropylene, and vinylidene fluoride. Silicon-containing vinyl monomers such as vinyltrimethoxysilane and vinyltriethoxysilane; maleic anhydride, maleic acid, monoalkyl and dialkyl esters of maleic acid; fumaric acid, monoalkyl and dialkyl esters of fumaric acid; maleimide, Methyl maleimide, ethyl maleimide, propyl maleimide, butyl maleimide, hexyl maleimide, octyl maleimide, dodecyl maleimide, stearyl maleimide, phenyl maleimide, cyclohexyl Maleimide monomers such as maleimide; Nitrile group-containing vinyl monomers such as acrylonitrile and methacrylonitrile; Amide group-containing vinyl monomers such as acrylamide and methacrylamide; Vinyl acetate, vinyl propionate, vinyl pivalate, vinyl benzoate, cinnamon Examples thereof include vinyl esters such as vinyl acid; alkenes such as ethylene and propylene; conjugated dienes such as butadiene and isoprene; vinyl chloride, vinylidene chloride, allyl chloride, and allyl alcohol.

  The (meth) acrylic acid ester monomer and vinyl monomer may be used alone or may be copolymerized. Especially, the polymer which consists of a styrene-type monomer and a (meth) acrylic-acid type monomer from the physical property of a product etc. is preferable. More preferred is a (meth) acrylic polymer comprising an acrylate monomer and a methacrylic acid ester monomer, and particularly preferred is an acrylic polymer comprising an acrylate monomer. In the present invention, these preferable monomers may be copolymerized with other monomers, and further block copolymerized, and in this case, it is preferable that these preferable monomers are contained in a mass ratio of 40% or more. . In the above expression format, for example, (meth) acrylic acid represents acrylic acid and / or methacrylic acid.

  The Tg of the (meth) acrylic acid ester-based polymer is not particularly limited, and either a high Tg type or a low Tg type can be used, but considering the adhesiveness, the use of a high Tg type is preferable. Is preferably 10 to 180 ° C, more preferably 20 to 120 ° C. Moreover, you may use together the (meth) acrylic acid ester-type polymer which has Tg of this range, and the (meth) acrylic acid ester-type polymer which has Tg outside this range. In the present specification, Tg is a calculated glass transition temperature calculated by the following formula (I).

... (I)

  In the formula (I), Tg is a calculated glass transition temperature of a (meth) acrylic acid ester-based polymer containing a crosslinkable silicon group, Wi is a monomer i (however, excluding a crosslinkable silicon group-containing compound) , Tgi indicates the glass transition temperature of the homopolymer of monomer i.

  It does not specifically limit as a synthesis method of a (meth) acrylic acid ester type polymer, What is necessary is just to carry out by a well-known method. However, a polymer obtained by a normal free radical polymerization method using an azo compound or a peroxide as a polymerization initiator has a problem that the molecular weight distribution is generally as large as 2 or more and the viscosity is increased. Yes. Therefore, in order to obtain a (meth) acrylate polymer having a narrow molecular weight distribution and a low viscosity and having a crosslinkable functional group at the molecular chain terminal at a high ratio. It is preferable to use a living radical polymerization method.

  The (meth) acrylic acid ester-based polymer having a crosslinkable silicon group may be used alone or in combination of two or more.

  These organic polymers having a crosslinkable silicon group may be used alone or in combination of two or more. Specifically, it comprises a polyoxyalkylene polymer having a crosslinkable silicon group, a saturated hydrocarbon polymer having a crosslinkable silicon group, and a (meth) acrylic acid ester polymer having a crosslinkable silicon group. An organic polymer obtained by blending two or more selected from the group can also be used.

A method for producing an organic polymer obtained by blending a polyoxyalkylene polymer having a crosslinkable silicon group and a (meth) acrylic acid ester polymer having a crosslinkable silicon group is disclosed in JP-A-59-122541. Although proposed in Japanese Laid-Open Patent Publication No. 63-112642, Japanese Laid-Open Patent Publication No. 6-172631, and Japanese Laid-Open Patent Publication No. 11-116763, the invention is not particularly limited thereto. A preferred specific example is a (meth) acrylic acid ester monomer unit having a crosslinkable silicon group and a molecular chain substantially having an alkyl group having 1 to 8 carbon atoms represented by the following general formula (5). And a polyoxyalkylene polymer having a crosslinkable silicon group in a copolymer comprising a (meth) acrylic acid ester monomer unit having an alkyl group having 10 or more carbon atoms and represented by the following general formula (6): It is a method of blending and producing a coalescence.
^{_{-CH 2 -C (R 3) (}} COOR 4) - (5)
^{_{-CH 2 -C (R 3) (}} COOR 5) - (6)

In the general formula (5), R ³ represents a hydrogen atom or a methyl group, and R ⁴ represents an alkyl group having 1 to 8 carbon atoms. R ^{4 in the} general formula (5) is, for example, 1 to 8 carbon atoms such as a methyl group, an ethyl group, a propyl group, an n-butyl group, a t-butyl group, or a 2-ethylhexyl group, preferably 1 to 4 carbon atoms. More preferred are 1 to 2 alkyl groups. The alkyl group of R ⁴ may alone, or may be a mixture of two or more.

In the general formula (6), R ³ is the same as above, and R ⁵ is an alkyl group having 10 or more carbon atoms. R ^{5 in the} general formula (6) is, for example, a long chain having 10 or more carbon atoms such as lauryl group, tridecyl group, cetyl group, stearyl group, behenyl group, etc., usually 10-30, preferably 10-20. And an alkyl group. Incidentally, as with the alkyl group for R ⁵ is a R ^4, alone may or may be a mixture of two or more.

The molecular chain of the (meth) acrylic acid ester-based copolymer is substantially composed of monomer units of the formulas (5) and (6), and the term “substantially” here refers to the copolymer. It means that the total of the monomer units of the formula (5) and the formula (6) present therein exceeds 50% by mass. The total of the monomer units of the formula (5) and the formula (6) is preferably 70% by mass or more.
The abundance ratio of the monomer unit of the formula (5) and the monomer unit of the formula (6) is preferably 95: 5 to 40:60, more preferably 90:10 to 60:40 in terms of mass ratio.
Examples of monomer units other than those represented by formulas (5) and (6) that may be contained in the copolymer include α, β-unsaturated carboxylic acids such as acrylic acid and methacrylic acid; acrylamide and methacrylamide , N-methylol acrylamide, amide groups such as N-methylol methacrylamide, epoxy groups such as glycidyl acrylate and glycidyl methacrylate, monomers containing amino groups such as diethylaminoethyl acrylate, diethylaminoethyl methacrylate, aminoethyl vinyl ether; other acrylonitriles, Examples thereof include monomer units derived from styrene, α-methylstyrene, alkyl vinyl ether, vinyl chloride, vinyl acetate, vinyl propionate, ethylene and the like.

  Organic polymers formed by blending a saturated hydrocarbon polymer having a crosslinkable silicon group and a (meth) acrylic acid ester copolymer having a crosslinkable silicon group are disclosed in JP-A-1-168774 and JP-A-2000-. Although it is proposed in Japanese Patent No. 186176, etc., it is not particularly limited thereto.

  Furthermore, as a method for producing an organic polymer obtained by blending a (meth) acrylic acid ester-based copolymer having a crosslinkable silicon functional group, in addition, in the presence of an organic polymer having a crosslinkable silicon group, A method of polymerizing a (meth) acrylic acid ester monomer can be used. This production method is specifically disclosed in JP-A-59-78223, JP-A-59-168014, JP-A-60-228516, JP-A-60-228517, etc. It is not limited to these.

  The silver powder (B) used for the conductive adhesive of the present invention includes a first silver powder (b1) and a second silver powder (b2) each having a predetermined specific surface area and tap density. The mixing ratio [(b1) / (b2)] of (b1) and (b2) is 1/10 to 10/1 in terms of mass ratio, and preferably 1/4 to 4/1. 4/1 is more preferable.

The specific surface area of the first silver powder (b1) is 0.5 m ² / g or more and less than 2 m ² / g, preferably 1.0 m ² / g or more and less than 2.0 m ² / g, and the tap density is 2.5. ˜6.0 g / cm ³ , preferably 3.0 to 5.0 g / cm ³ . The 50% average particle size of the first silver powder (b1) is preferably 1 to 15 μm.
In the present specification, the specific surface area of silver powder was measured by the BET method (gas adsorption method), and the tap density was measured by a method according to the 20.2 tap method of JIS K5101-1991. The 50% average particle diameter means a particle diameter at 50% cumulative volume measured by a laser diffraction / scattering particle size distribution measurement method.

  There is no restriction | limiting in particular in the shape of said 1st silver powder (b1), Although various shapes, such as flake shape and a granular form, can be used, Flaky silver powder is suitable. In the present invention, the flake shape includes a shape called a flat shape, a flake shape, or a scale shape, and is a shape obtained by crushing a solid shape such as a spherical shape or a lump shape in one direction. In addition, granular means all shapes that are not flaked, for example, a shape in which powder is agglomerated in a bunch of grapes, a spherical shape, a substantially spherical shape, a lump shape, a dendritic shape, and these shapes. Examples thereof include a silver powder mixture.

The specific surface area of the second silver powder (b2) is 2 m ² / g or more and 7 m ² / g or less, preferably 2.0 m ² / g or more and 3.0 m ² / g or less, and the tap density is 1.0-3. 0.0 g / cm ³ . The 50% average particle size of the second silver powder (b2) is preferably 0.5 to 3.0 μm.

  There is no restriction | limiting in particular in the shape of said 2nd silver powder (b2), Although various shapes, such as flake shape and a granular form, can be used, granular silver powder is suitable.

  There is no restriction | limiting in particular in the manufacturing method of (B) silver powder used for this invention, It can obtain by a well-known method. (B) When flaky silver powder is used as the silver powder, for example, silver powder such as spherical silver powder, bulk silver powder, and granular silver powder is obtained by mechanically pulverizing the powder using a known apparatus such as a jet mill, roll mill, or ball mill. be able to. (B) When granular silver powder is used as the silver powder, for example, an electrolytic method, a pulverization method, a heat treatment method, an atomization method, a reduction method, and the like can be given. Among these, the reduction method is preferable because a powder having a small tap density is easily obtained by controlling the reduction method.

  In this invention, the content rate of the said (B) silver powder is 65 to 85 mass% of the total content of a conductive adhesive, and 70 to 80 mass% is more preferable. If the content is less than 65% by mass, sufficient conductivity may not be obtained. If the content is more than 85% by mass, the electrical conductivity is excellent, but the adhesion and workability may be significantly reduced. In particular, when the content rate of the second silver powder (b2) is increased, the tendency of the adhesiveness and workability to decrease is more remarkable.

In the present invention, by using one or more types of silica selected from the group consisting of hydrophobic silica and hydrophilic silica that have been hydrophobized with a specific surface treatment agent together with components (A) and (B). In particular, an adhesive composition having excellent conductivity stability can be obtained.
The particle size of the silica (C) is not particularly limited, but silica fine powder is preferable, silica fine powder having an average particle size of 7 to 16 nm is more preferable, and silica fine powder having an average particle size of 7 to 14 nm is most preferable.

  As the hydrophilic silica used in the conductive adhesive of the present invention, known hydrophilic silica can be widely used, but fumed silica having silanol groups (Si—OH groups) on the surface is preferable. By using hydrophilic silica in the present invention, bleeding can be prevented while ensuring flowability without increasing viscosity. In the present invention, the conductive adhesive having flowability is suitably used for applications that require flowability, for example, applications that are applied to a substrate by a screen printing method to form a pattern with a thin film of about 50 μm.

  The hydrophobic silica used in the conductive adhesive of the present invention is selected from the group consisting of dimethyldichlorosilane, hexamethyldisilazane, (meth) acrylsilane, octylsilane (for example, trimethoxyoctylsilane), and aminosilane. Hydrophobic silica hydrophobized with one or more surface treatment agents is used. By using hydrophobic silica hydrophobized by the specific surface treatment agent described above in the present invention, bleeding can be prevented while ensuring dischargeability and shape retention. In the present invention, the conductive adhesive having shape retentivity is required to have a film thickness of 100 μm or more in applications requiring shape retentivity, for example, when a pattern is formed by applying a screen printing method to a substrate. It is suitable for a case where the connection portion by solder is replaced with the conductive adhesive of the present invention.

  As the method for hydrophobizing silica using the surface treatment agent, a known method can be selected. For example, the above-described surface treatment agent is sprayed on untreated silica, or the vaporized surface treatment agent is mixed and heated. The method of processing is mentioned. In addition, it is preferable to perform this hydrophobization process by the dry type in nitrogen atmosphere.

  Although there is no restriction | limiting in particular in the mixture ratio of the said component (C), It is preferable to use 3-20 mass parts with respect to 100 mass parts of (A) component, and it is more preferable to use 5-10 mass parts. The said silica may be used independently and may be used together 2 or more types.

  The conductive adhesive of the present invention further includes (D1) an amine compound having at least one alkoxysilyl group in one molecule, and (D2) a compound that reacts with water to form the (D1) amine compound. Therefore, the adhesiveness can be improved, which is preferable. The manufacturing method of the said (D1) compound is not specifically limited, A well-known method can be used.

  Examples of the amine compound (D1) having at least one alkoxysilyl group in one molecule include those represented by the following general formula (7).

In the general formula (7), n = 0, 1 or 2, preferably 0 or 1. R ⁶ and R ⁷ are the same or different and are each a hydrocarbon group having 1 to 4 carbon atoms, such as an alkyl group such as methyl, ethyl, propyl, and butyl, an alkenyl group such as vinyl, allyl, propenyl, and butenyl. An alkyl group is particularly preferable. R ⁸ is a hydrocarbon group having 1 to 10 carbon atoms, preferably an alkylene group such as methylene, ethylene, propylene, or butylene, an arylene group such as phenylene, an alkylene arylene group, or the like, and particularly preferably an alkylene group. Z is a hydrogen atom or an aminoalkyl group having 1 to 4 carbon atoms.

  Specific examples of the amine compound (D1) having at least one alkoxysilyl group in one molecule include compounds represented by the following formulas (8) to (15), N- (β-aminoethyl)- Examples include aminosilanes represented by γ-aminopropyltrimethoxysilane, N- (β-aminoethyl) -γ-aminopropylmethyldimethoxysilane, and the like. Among these, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldimethoxysilane, N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane and the like are adhesive. Is particularly preferable.

Specifically, the compound (D2) is an amine compound ketimine having at least one alkoxysilyl group in one molecule from the viewpoints of easy availability of raw materials, storage stability, and reactivity with water. Preferred examples include compounds, enamine compounds, and / or aldimine compounds.
Each of the ketimine compound, enamine compound and aldimine compound can be obtained by a dehydration reaction between an amine compound (D1) having at least one alkoxysilyl group in one molecule and a carbonyl compound.

  Known examples of the carbonyl compound include aldehydes such as acetaldehyde, propionaldehyde, n-butyraldehyde, isobutyraldehyde, n-amylaldehyde, isohexaldehyde, diethylacetaldehyde, glyoxal, benzaldehyde, phenylacetaldehyde; Cyclic ketones such as cyclopentanone, trimethylcyclopentanone, cyclohexanone, methylcyclohexanone and trimethylcyclohexanone; acetone, methyl ethyl ketone, methyl propyl ketone, methyl isopropyl ketone, methyl isobutyl ketone, methyl-tert-butyl ketone, diethyl ketone, dipropyl ketone , Aliphatic ketones such as diisopropyl ketone, dibutyl ketone, diisobutyl ketone; Aromatic ketones such as tophenone, benzophenone, propiophenone; and the following general formula (16) such as acetylacetone, methyl acetoacetate, ethyl acetoacetate, dimethyl malonate, diethyl malonate, methyl ethyl malonate, and dibenzoylmethane However, it is not limited to these. Among these, methyl isobutyl ketone, dipropyl ketone, phenylacetaldehyde, and a β-dicarbonyl compound having an active methylene group [compound represented by the following general formula (16)] are more preferable.

In the general formula (16), R ⁹ and R ¹⁰ are the same or different and are each an alkyl group having 1 to 16 carbon atoms (for example, methyl, ethyl, propyl, butyl, heptyl, hexyl, octyl, nonyl, decyl, Undecyl, hexadecyl, etc.), aryl groups having 6 to 12 carbon atoms (for example, phenyl, tolyl, hexyl, naphthyl, etc.), or alkoxyl groups having 1 to 4 carbon atoms (for example, methoxy, ethoxy, prooxy, putoxy, etc.) Means.

  The compound that reacts with water to produce an amine compound having at least one alkoxysilyl group in one molecule is not particularly limited, and a compound obtained by a known production method can be used. Is 50 to 95%, preferably 70 to 95%, more preferably 80 to 95%, and the amino group blocking ratio is 90% or more, preferably 95% or more.

  The blending ratio of the components (D1) and (D2) is not particularly limited, but is preferably 1 to 20 parts by mass with respect to 100 parts by mass of the component (A). Said (D1) and (D2) may be used independently and may be used together 2 or more types.

  The conductive adhesive of the present invention includes a curing catalyst, a filler, a plasticizer, an adhesion-imparting agent, a stabilizer, a colorant, and physical property adjustment as necessary in order to adjust viscosity and physical properties in addition to the components described above. Agents, thixotropic agents, dehydrating agents (storage stability improvers), tackifiers, sagging inhibitors, UV absorbers, antioxidants, flame retardants, radical polymerization initiators, and various solvents such as toluene and alcohol May be blended, or other compatible polymers may be blended.

  Examples of the curing catalyst include titanic acid esters such as tetrabutyl titanate and tetrapropyl titanate; organotin compounds such as dibutyltin dilaurate, dibutyltin maleate, dibutyltin diacetate, tin octylate and tin naphthenate: lead octylate Butylamine, octylamine, laurylamine, dibutylamine, monoethanolamine, diethanolamine, triethanolamine, diethylenetriamine, triethylenetetramine, oleylamine, cyclohexylamine, benzylamine, diethylaminopropylamine, xylylenediamine, triethylenediamine, guanidine, diphenyl Guanidine, 2,4,6-tris (dimethylaminomethyl) phenol, morpholine, N-methylmorpholine, 1,8-diazabicycle (5.4.0) amine compounds such as undecene-7 (DBU) or salts thereof with carboxylic acids, etc .; low molecular weight polyamide resins obtained from excess polyamines and polybasic acids; excess polyamines and epoxy compounds Reaction products of the above and known silanol composite catalysts such as silane coupling agents having an amino group such as r-aminopropyltrimethoxysilane and N- (β-aminoethyl) aminopropylmethyldimethoxysilane. These catalysts may be used alone or in combination of two or more.

  Examples of the plasticizer include phthalic acid esters such as dibutyl phthalate, diheptyl phthalate, di (2-ethylhexyl) phthalate, and butyl benzyl phthalate; Basic acid esters; Aliphatic esters such as butyl oleate and methyl acetylricinoleate; Phosphate esters such as tricresyl phosphate and tributyl phosphate; Trimellitic acid esters; Chlorinated paraffins; Alkyldiphenyl, Partial Hydrocarbon oils such as hydrogenated terphenyl; process oils; epoxy plasticizers such as epoxidized soybean oil and epoxy benzyl stearate.

  Moreover, a polymeric plasticizer can be used. When a high-molecular plasticizer is used, the initial physical properties are maintained over a long period of time as compared with the case where a low-molecular plasticizer that is a plasticizer containing no polymer component in the molecule is used. Specific examples of the polymer plasticizer include vinyl polymers obtained by polymerizing vinyl monomers by various methods; esters of polyalkylene glycols such as diethylene glycol dibenzoate, triethylene glycol dibenzoate, and pentaerythritol ester; Polyester plasticizer obtained from dibasic acids such as sebacic acid, adipic acid, azelaic acid and phthalic acid and dihydric alcohols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol and dipropylene glycol; Are 1000 or more polyether polyols such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, etc., or the hydroxyl groups of these polyether polyols are ester groups, ethers Polyethers such as derivatives converted into groups, etc .; polystyrenes such as polystyrene and poly-α-methylstyrene; polybutadiene, polybutene, polyisobutylene, butadiene-acrylonitrile, polychloroprene, and the like, but are not limited thereto is not.

  Of these polymer plasticizers, those compatible with the polymer of component (A) are preferred. From this point, polyethers and vinyl polymers are preferable. Further, when polyethers are used as a plasticizer, the surface curability and deep part curability are improved, and the curing delay after storage does not occur. Polypropylene glycol is more preferred. Moreover, a vinyl polymer is preferable from the viewpoint of compatibility, weather resistance, and heat resistance. Among vinyl polymers, acrylic polymers and / or methacrylic polymers are preferred, and acrylic polymers such as polyacrylic acid alkyl esters are more preferred. The polymer synthesis method is preferably a living radical polymerization method and more preferably an atom transfer radical polymerization method because the molecular weight distribution is narrow and viscosity can be lowered. Moreover, it is preferable to use a polymer obtained by so-called SGO process obtained by continuous bulk polymerization of an alkyl acrylate monomer described in JP-A-2001-207157 at high temperature and high pressure.

The number average molecular weight of the polymer plasticizer is preferably 500 to 15000, more preferably 800 to 10000, still more preferably 1000 to 8000, and particularly preferably 1000 to 5000. Most preferably, it is 1000-3000. If the molecular weight is too low, the plasticizer flows out over time due to heat or the like, and the initial physical properties cannot be maintained for a long time. Moreover, when molecular weight is too high, a viscosity will become high and workability | operativity will worsen. The molecular weight distribution of the polymer plasticizer is not particularly limited, but is preferably narrow and is preferably less than 1.80. 1.70 or less is more preferable, 1.60 or less is more preferable, 1.50 or less is more preferable, 1.40 or less is particularly preferable, and 1.30 or less is most preferable.
The number average molecular weight is measured by a GPC method in the case of a vinyl polymer, and by a terminal group analysis method in the case of a polyether polymer. Moreover, it is measured by molecular weight distribution (Mw / Mn) GPC method (polystyrene conversion).

  The polymer plasticizer may not have a crosslinkable silicon group, but may have a crosslinkable silicon group. When it has a crosslinkable silicon group, it acts as a reactive plasticizer and can prevent migration of the plasticizer from the cured product. In the case of having a crosslinkable silicon group, the average number per molecule is preferably 1 or less, and more preferably 0.8 or less. When using a plasticizer having a crosslinkable silicon group, particularly an oxyalkylene polymer having a crosslinkable silicon group, the number average molecular weight must be lower than that of the polymer of component (A).

A plasticizer may be used independently and may use 2 or more types together. Further, a low molecular plasticizer and a high molecular plasticizer may be used in combination. These plasticizers can also be blended at the time of polymer production.
The amount of the plasticizer used is 5 to 150 parts by mass, preferably 10 to 120 parts by mass, and more preferably 20 to 100 parts by mass with respect to 100 parts by mass of the polymer of component (A). If it is less than 5 parts by mass, the effect as a plasticizer will not be exhibited, and if it exceeds 150 parts by mass, the mechanical strength of the cured product will be insufficient.

  Fillers include reinforcing silica such as fume silica, precipitated silica, crystalline silica, fused silica, dolomite, anhydrous silicic acid, hydrous silicic acid, and carbon black; heavy calcium carbonate, colloidal calcium carbonate, magnesium carbonate Diatomaceous earth, calcined clay, clay, talc, titanium oxide, bentonite, organic bentonite, ferric oxide, aluminum fine powder, flint powder, zinc oxide, activated zinc white, shirasu balloon, glass microballoon, phenolic resin and vinylidene chloride Examples include fillers such as resin organic microballoons, PVC powder, PMMA powder, and the like; fibrous fillers such as asbestos, glass fibers, and filaments.

  When using a filler, the usage-amount is 1-250 mass parts with respect to 100 mass parts of polymers of (A) component, Preferably it is 10-200 mass parts. These fillers may be used alone or in combination of two or more.

  As described in JP-A No. 2001-181532, the filler is uniformly mixed with a dehydrating agent such as calcium oxide, sealed in a bag made of an airtight material, and left for an appropriate time. It is also possible to dehydrate and dry in advance. By using this low water content filler, storage stability can be improved particularly when a one-component composition is used.

  When you want to obtain a hardened product with high strength by using these fillers, mainly fume silica, precipitated silica, crystalline silica, fused silica, dolomite, silicic anhydride, hydrous silicic acid and carbon black, surface treatment fine A filler selected from calcium carbonate, calcined clay, clay, activated zinc white and the like is preferable, and if used in the range of 1 to 200 parts by mass with respect to 100 parts by mass of the organic polymer (A) having a crosslinkable silicon group. Favorable results are obtained. In addition, when it is desired to obtain a cured product having low strength and high elongation at break, mainly calcium carbonate such as titanium oxide and heavy calcium carbonate, magnesium carbonate, talc, ferric oxide, zinc oxide, and shirasu balloon When a filler selected from the above is used in an amount of 5 to 200 parts by mass with respect to 100 parts by mass of the organic polymer (A) having a crosslinkable silicon group, preferable results are obtained. In general, calcium carbonate has a greater effect of improving the breaking strength, breaking elongation, and adhesiveness of the cured product as the value of the specific surface area increases. When calcium carbonate is used, it is desirable to use a combination of surface treated fine calcium carbonate and heavy calcium carbonate such as heavy calcium carbonate. The particle diameter of the surface-treated fine calcium carbonate is preferably 0.5 μm or less, and the surface treatment is preferably treated with a fatty acid or a fatty acid salt. Moreover, the particle size of calcium carbonate having a large particle size is preferably 1 μm or more, and an untreated surface can be used.

  In order to improve the workability (such as sharpness) of the composition and to make the surface of the cured product matt, it is preferable to add an organic balloon or an inorganic balloon. These fillers can be surface-treated, and may be used alone or in combination of two or more. In order to improve workability (such as sharpness), the balloon particle size is preferably 0.1 mm or less. In order to make the surface of the cured product matt, 5-300 μm is preferable.

  A silane coupling agent or the like is used as an adhesion-imparting agent, and a hindered phenol compound or a triazole compound is used as a stabilizer. Examples of the colorant include titanium white, carbon black, and bengara.

  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 normal temperature by atmospheric moisture, and is suitably used as a normal temperature moisture curable conductive adhesive, but if necessary, curing is accelerated by heating as appropriate. You may let them.

  The conductive adhesive of the present invention has high conductivity by being applied or printed on a substrate and cured, and can be used instead of solder. The conductive adhesive of the present invention is suitably used for applications such as bonding and mounting of electronic parts such as semiconductor element chip parts and discrete parts, circuit connection, bonding and fixing of crystal resonators and piezoelectric elements, and sealing of packages. . Using the conductive adhesive of the present invention, a circuit in which one or more electronic components such as semiconductor elements, chip components, and discrete components are joined can be formed on the substrate surface.

  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 resulting 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, 22 parts by mass of γ-methacryloxypropyltrimethoxysilane, 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, 8 parts by mass of 3-mercaptopropyltrimethoxysilane 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 were distilled off to obtain an acrylate polymer A3 having a trimethoxysilyl group having a polystyrene-equivalent mass average molecular weight of about 6000 and a Tg of 61.2 ° C.

(Synthesis Example 4)
Under a nitrogen atmosphere, CuBr (1.09 kg), acetonitrile (11.4 kg), butyl acrylate (26.0 kg) and diethyl 2,5-dibromoadipate (2.28 kg) were added to a 250 L reactor, and 70-80 Stir at about 30 minutes. To this was added pentamethyldiethylenetriamine to initiate the reaction. 30 minutes after the start of the reaction, butyl acrylate (104 kg) was continuously added over 2 hours. During the reaction, pentamethyldiethylenetriamine was appropriately added so that the internal temperature became 70 ° C to 90 ° C. The total amount of pentamethyldiethylenetriamine used so far was 220 g. Four hours after the start of the reaction, volatile components were removed by heating and stirring at 80 ° C. under reduced pressure. Acetonitrile (45.7 kg), 1,7-octadiene (14.0 kg) and pentamethyldiethylenetriamine (439 g) were added thereto, and stirring was continued for 8 hours. The mixture was heated and stirred at 80 ° C. under reduced pressure to remove volatile components. Toluene is added to this concentrate to dissolve the polymer, diatomaceous earth is added as a filter aid, aluminum silicate and hydrotalcite are added as adsorbents, and an oxygen-nitrogen mixed gas atmosphere (oxygen concentration 6%) is set to an internal temperature of 100. The mixture was heated and stirred at ° C. The solid content in the mixed solution was removed by filtration, and the filtrate was heated and stirred at an internal temperature of 100 ° C. under reduced pressure to remove volatile components.

Furthermore, aluminum silicate, hydrotalcite, and a heat deterioration inhibitor were added as adsorbents to this concentrate, and the mixture was heated and stirred under reduced pressure (average temperature of about 175 ° C., reduced pressure of 10 Torr or less).
Further, aluminum silicate and hydrotalcite were added as adsorbents, an antioxidant was added, and the mixture was heated and stirred at an internal temperature of 150 ° C. in an oxygen-nitrogen mixed gas atmosphere (oxygen concentration 6%). Toluene was added to this concentrate to dissolve the polymer, and then the solid content in the mixed solution was removed by filtration. The filtrate was heated and stirred under reduced pressure to remove volatile matter, and the polymer having an alkenyl group was removed. Obtained. Polymer having this alkenyl group, dimethoxymethylsilane (2.0 molar equivalents relative to alkenyl group), methyl orthoformate (1.0 molar equivalents relative to alkenyl group), platinum catalyst [bis (1,3-divinyl (-1,1,3,3-tetramethyldisiloxane) Platinum complex catalyst xylene solution 10 mg of 1 kg of polymer was mixed, and the mixture was heated and stirred at 100 ° C. in a nitrogen atmosphere. After confirming disappearance of the alkenyl group, the reaction mixture was concentrated to obtain a poly (acrylic acid-n-butyl) polymer A4 having a dimethoxysilyl group at the terminal. The number average molecular weight of the obtained polymer A4 was about 26000, the molecular weight distribution was 1.3, and the Tg was −56.0 ° C. When the average number of silyl groups introduced per molecule of the polymer was determined by 1H NMR analysis, it was about 1.8.

(Synthesis Example 5)
20.00 g of ethyl acetate was added to a flask equipped with a stirrer, a nitrogen gas inlet tube, a thermometer and a reflux condenser, and heated to 80 ° C. In a separate container, butyl acrylate (Tokyo Chemical Industry Co., Ltd. 100.00 g, 3-methacryloxypropyltrimethoxysilane (trade name: KBM503, Shin-Etsu Chemical Co., Ltd.) 1.00 g, 3-mercaptopropyltrimethoxy Silane (trade name: KBM803, manufactured by Shin-Etsu Chemical Co., Ltd.) 1.20 g, and AIBN [2,2′-azobisisobutyronitrile (V-60, manufactured by Wako Pure Chemical Industries, Ltd.)] 0. 40 g was added, and the mixture was added dropwise in a dropping funnel over 2 hours, and further reacted for 4 hours at 80 ° C. After the reaction for 6 hours in total, the temperature of the reaction product was returned to room temperature, and the reaction product was mixed with a benzoquinone solution (95% THF 20.00 g of solution) was added to terminate the polymerization, and a (meth) acrylic acid ester-based polymer A5 having a trimethoxysilyl group was obtained with a peak top molecular weight of 21000. A molecular weight distribution of 2.4, Tg is trimethoxysilyl groups contained by .H1-NMR measurement was -56.0 ° C. was 2.08 per molecule.

Example 1
As shown in Table 1, a total of 100 parts by mass of the crosslinkable silyl group-containing polymers A1 to A3 obtained in Synthesis Examples 1 to 3 was added as a hindered phenol antioxidant (BASF, product). Name: Irganox 245) 3 parts by mass, hindered amine anti-aging agent (manufactured by BASF, trade name: Tinuvin 765) as an anti-aging agent, hydrophilic silica (manufactured by Tokuyama Co., Ltd., trade name: Leolosil QS-20) ) After 5 parts by mass was stirred and defoamed with a stirrer and mixer, it was dehydrated by heating at 100 ° C for 1 hour and cooled to 50 ° C or lower. Subsequently, 30 parts by mass of a paraffinic diluent (manufactured by Japan Energy Co., Ltd., trade name: Cactus normal paraffin N-11) as a diluent, and tetraethoxysilane (manufactured by Colcoat Co., Ltd., trade name: ethyl silicate 28) as a dehydrating agent. ) 2 parts by mass, followed by sill coat AgC-B (specific surface area 1.35 m ² / g, tap density 4.6 g / cm ³ , 50% average particle size 4 μm, trade name, Fukuda Metals as the first silver powder (b1) As a second silver powder (b2), Silcote AgC-G (specific surface area 2.5 m ² / g, tap density 1.4 g / cm ³⁾ Fukuda Metal Foil Powder Co., Ltd. product name, granular silver powder) 200 parts by mass, MIBK (methyl isobutyl ketone) and 3-aminopropyltrimethoxysilane reaction product (Shin-Etsu Chemical) 9 parts by mass, trade name: Shin-Etsu Silicone X-12-812H), and 2 parts by mass of dioctyl tin-based curing catalyst (manufactured by Nitto Kasei Co., Ltd., trade name: Neostan U-830P) are added as a curing catalyst. The mixture was stirred and degassed to obtain an adhesive composition.

In Table 1, the compounding quantity of each compounding substance is shown by g. In addition, the compounding quantity of (meth) acrylic acid ester polymer A3 is shown by solid content. * 1 to * 10 are as follows.
* 1) Silcote AgC-B: trade name of Fukuda Metal Foil Powder Industry Co., Ltd., specific surface area 1.35 m ² / g, tap density 4.6 g / cm ³ , 50% average particle size 4 μm, flaky silver powder.
* 2) SILCOAT AgC-G: trade name, specific surface area 2.5 m ² / g, tap density 1.4 g / cm ³ , granular silver powder (reduced powder) manufactured by Fukuda Metal Foil Powder Industry Co., Ltd.).
* 3) Phenol antioxidant, trade name Irganox 245, manufactured by BASF.
* 4) Amine-based antioxidant, trade name Tinuvin 765, manufactured by BASF.
* 5) Hydrophilic silica, trade name: Leolosil QS-20, manufactured by Tokuyama Corporation.
* 6) Paraffin-based diluent, trade name: Cactus normal paraffin N-11, manufactured by Japan Energy Co., Ltd.
* 7) Ethyl silicate, trade name: Ethyl silicate 28, manufactured by Colcoat Co., Ltd.
* 8) Reaction product of MIBK and 3-aminopropyltrimethoxysilane, trade name: Shin-Etsu Silicone X-12-812H, manufactured by Shin-Etsu Chemical Co., Ltd.
* 9) 3-aminopropyltrimethoxysilane, trade name: KBM-903, manufactured by Shin-Etsu Chemical Co., Ltd.
* 10) Dioctyltin compound, trade name: Neostan U-830, manufactured by Nitto Kasei Co., Ltd.

The following measurements 1) to 7) were performed on the obtained adhesive composition. The results are shown in Table 2.
1) Measurement of volume resistivity The adhesive composition was stretched to a thickness of about 200 μm using a spacer, and cured at 23 ° C. and 50% RH for 7 days to prepare a cured sheet. The volume resistivity was measured by a four-end needle method using Lorester MCP-T360 manufactured by Mitsubishi Chemical Corporation. The volume resistivity is not less than 1 × 10 ⁷ Ω · cm, which is the upper limit value determined at the time of measurement. D. It was.

2) Thermal aging test After preparing a cured product sheet by the same method as the volume resistivity measurement, the cured product sheet was adjusted to 80 ° C, 100 ° C, 120 ° C or 130 ° C for 4 weeks in a hot-air circulating dryer. It was left to stand and the state of the film was observed. The case where the film is almost unchanged from the initial stage and the bendability is maintained is indicated as ◯, the case where the deterioration has progressed and the bendability is lost △, the case where the shape of the film was not retained after heat aging X.

3) Adhesive test The adhesive composition was applied to alumite aluminum and a copper plate degreased with methyl ethyl ketone using a glass rod so as to have a thickness of 100 μm. After 3 minutes of open time, they were bonded together and cured for 7 days in an environment of 23 ° C. and 50% RH. The adhesion test was based on JISK6854, and the tensile shear bond strength was measured at a test speed of 50 mm / min. Adhesive strength of 2.0 N / mm ² or more is ◎, 1.0 N / mm ² or more and less than 2.0 N / mm ² is ◯, 0.5 N / mm ² or more and less than 1.0 N / mm ² is Δ, 0.5 N Less than / mm ² was evaluated as x.

4) Sedimentation / bleed test The adhesive composition was filled in a glass bottle, left in a hot-air circulating drier adjusted to 50 ° C. for 1 week, and the appearance was observed. The evaluation criteria are as follows.
○: No sedimentation / bleeding, x: sedimentation or bleeding.

5) Conductivity stability test 4) Each adhesive composition after standing for 1 week at 50 ° C. obtained in the sedimentation / bleed test was stretched to a thickness of about 200 μm using a spacer, and 23 ° C., 50%. Cured for 7 days under RH to produce a cured sheet. The volume resistivity was measured by a four-end needle method using Lorester MCP-T360 manufactured by Mitsubishi Chemical Corporation, and the result was described.

6) Dischargeability test 4) Each adhesive composition after left for 1 week at 50 ° C. obtained in the sedimentation / bleed test was filled into a 10 cc polyethylene syringe (manufactured by Musashi Engineering Co., Ltd., PSY-10E). Sealed using a polyethylene plunger (MLP-10E, manufactured by Musashi Engineering Co., Ltd.). A polyethylene taper nozzle [manufactured by Musashi Engineering Co., Ltd., TPND-18G (inner diameter: 0.84 mm), and TPND-22G (inner diameter: 0.40 mm)] was attached to the syringe, and a discharge property test was performed based on the following conditions. As the dispense controller, ML-808FX manufactured by Musashi Engineering Co., Ltd. is used, the controller introduction pressure is 0.5 MPa, and the discharge pressure is 300 kPa.
TPND-18G: The discharge amount for 2 seconds is measured at a discharge pressure of 300 kPa, and the average weight of 20 times is calculated.
TPND-22G: The discharge amount for 5 seconds is measured at a discharge pressure of 300 kPa, and the average weight of 20 times is calculated.
The judgment criteria are as follows.
TPND-18G: ○ for 0.05 g or more, Δ for 0.03 g or more and less than 0.05 g, and × for less than 0.03 g.
TPND-22G: O for 0.02 g or more, x for less than 0.02 g.

7) Flowability test and shape retention test 6) Adhesive composition immediately after production using the discharge system of the dischargeability test (initial stage) and an adhesive composition left for 1 week in a hot-air circulating dryer adjusted to 50 ° C Using a product (after storage), a dot having a size of φ1 ± 0.1 mm was prepared on a PET sheet having a thickness of 25 μm to obtain a test piece. The test piece was immediately left in a hot air circulating dryer adjusted to 50 ° C. for 10 minutes, and the change in dot size before and after heating was observed.
Judgment criteria are as follows.
・ Evaluation criteria of flow property test: O: Change in size is 30% or more, X: Change in size is less than 30%.
・ Evaluation criteria of shape retention test: O: Change in size is less than 30%, X: Change in size is 30% or more.

  Moreover, the circuit sample was produced with the following method using the obtained adhesive composition. The conductive adhesive was stencil printed on the copper surface of the copper-clad glass epoxy circuit board using a metal mask having a thickness of 75 μm. A tin-plated 2012 size chip resistor was crimped to this, cured for 7 days in an environment of 23 ° C. and 50% RH, and the adhesive was cured to connect the chip resistor to the circuit board. A circuit sample was prepared.

  The obtained circuit sample was subjected to 1000 cycles in a heat cycle test in which “left at 150 ° C. for 30 minutes”, “left at 85 ° C. and 85% RH for 30 minutes” and “left at −40 ° C. for 30 minutes” was one cycle. After that, when the presence or absence of peeling of the chip resistor was confirmed visually, there was no peeling.

(Examples 2 to 6)
As shown in Table 1, an adhesive composition was obtained in the same manner as in Example 1 except that the formulation was changed. Measurements 1) to 7) were performed on the obtained adhesive composition in the same manner as in Example 1. The results are shown in Table 2.

(Examples 7 to 13)
As shown in Table 3, an adhesive composition was obtained in the same manner as in Example 1 except that the formulation was changed. Measurements 1) to 7) were performed on the obtained adhesive composition in the same manner as in Example 1. The results are shown in Table 4.

In Table 3, the compounding quantity of each compounding substance is shown by g. In addition, the compounding quantity of (meth) acrylic acid ester polymer A3 and A5 is shown by solid content. * 1 to 10 are the same as in Table 1, and * 11 to * 13 are as follows.
* 11) Methyldimethoxysilyl group-terminated polyisobutylene, trade name: EPION EP505S, manufactured by Kaneka Corporation.
* 12) Silcote AgC-156I: trade name of Fukuda Metal Foil Powder Co., Ltd., specific surface area 0.7 to 1.3 m ² / g, tap density 4.00 to 6.00 g / cm ³ , 50% average Particle size 2 to 3 μm, high purity granular silver powder (reduced powder).
* 13) Reactive product of dibutyltin salt and normal ethyl silicate, trade name: Neostan U-700ES, manufactured by Nitto Kasei Co., Ltd.

(Examples 14 to 22)
As shown in Table 5, an adhesive composition was obtained in the same manner as in Example 1 except that the formulation was changed. Measurements 1) to 7) were performed on the obtained adhesive composition in the same manner as in Example 1. The results are shown in Table 6.

In Table 5, the compounding quantity of each compounding substance is shown by g. In addition, the compounding quantity of (meth) acrylic acid ester polymer A3 is shown by solid content. * 1 to 7, 9 and 10 are the same as those in Table 1, and * 14 to * 20 are as follows.
* 14) Hydrophobic silica, trade name: Aerosil R972 (dimethyldichlorosilane-treated silica), manufactured by Nippon Aerosil Co., Ltd.
* 15) Hydrophobic silica, trade name: Aerosil R974 (dimethyldichlorosilane-treated silica), manufactured by Nippon Aerosil Co., Ltd.
* 16) Hydrophobic silica, trade name: Aerosil R805 (octylsilane-treated silica), manufactured by Nippon Aerosil Co., Ltd.
* 17) Hydrophobic silica, trade name: Aerosil RX200 (hexamethyldisilazane-treated silica), manufactured by Nippon Aerosil Co., Ltd.
* 18) Hydrophobic silica, trade name: Aerosil R711 (methacrylic silane-treated silica), manufactured by Nippon Aerosil Co., Ltd.
* 19) Hydrophobic silica, trade name: Aerosil R976 (dimethyldichlorosilane-treated silica), manufactured by Nippon Aerosil Co., Ltd.
* 20) Hydrophobic silica, trade name: Aerosil RX300 (hexamethyldisilazane-treated silica), manufactured by Nippon Aerosil Co., Ltd.

(Comparative Examples 1-5)
As shown in Table 7, an adhesive composition was obtained in the same manner as in Example 1 except that the formulation was changed. The obtained adhesive composition was measured in the same manner as in Example 1. The results are shown in Table 8. In Comparative Examples 1 to 5, since the initial conductivity was unstable, the conductivity stability test, the flow property test, the shape stability test, and the discharge property test were not performed.

In Table 7, the compounding quantity of each compounding substance is shown by g. * 1, 3-8 and 10 are the same as those in Table 1, and * 21 to * 25 are as follows.
* 21) Silcote AgC-A: Fukuda Metal Foil Powder Co., Ltd. trade name, specific surface area 0.8 m ² / g, tap density 3.0 g / cm ³ , 50% average particle size 5 μm, flaky silver powder.
* 22) SA-31812: trade name of METALOR, specific surface area 0.4 m ² / g, tap density 5.6 g / cm ³ , 50% average particle size 4.3 μm, flaky silver powder.
* 23) Ag-3500S: trade name manufactured by Osaki Kogyo Co., Ltd., specific surface area 0.7 m ² / g, tap density 3.8 g / cm ³ , average particle size (SEM) 1.0 μm, spherical silver powder.
* 24) Ag-3500L: trade name, manufactured by Osaki Kogyo Co., Ltd., specific surface area 0.3 m ² / g, tap density 4.3 g / cm ³ , average particle size (SEM) 3.0 μm, spherical silver powder.
* 25) Ag-2000S: trade name, manufactured by Osaki Kogyo Co., Ltd., specific surface area 1.2 m ² / g, tap density 3.0 g / cm ³ , 50% average particle size 2.5 μm, amorphous silver powder.

(Comparative Example 6)
As shown in Table 9, the composition was adjusted in the same manner as in Example 1 except that the formulation was changed. However, the crosslinkable silyl group-containing organic polymer and silver powder were not collected, and the adhesive composition could not be adjusted. The measurement test was not possible.

(Comparative Examples 7 to 10)
As shown in Table 9, an adhesive composition was obtained in the same manner as in Example 1 except that the formulation was changed. The obtained adhesive composition was measured in the same manner as in Example 1. The results are shown in Table 10.

In Table 9, the compounding quantity of each compounding substance is shown by g. * 1 to 8 and 10 are the same as in Table 1, * 11 is the same as in Table 3, * 21 is the same as in Table 7, and * 26 to * 28 are as follows.
* 26) Aerosil RY200S, hydrophobic silica surface-treated with dimethyl silicone oil, manufactured by Nippon Aerosil Co., Ltd.
* 27) Fatty acid amide wax, trade name: Disparon # 6500, manufactured by Enomoto Kasei Co., Ltd.
* 28) N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, trade name: KBM-603, manufactured by Shin-Etsu Chemical Co., Ltd.

As shown in Tables 2, 4 and 6, all of the conductive adhesives of Examples 1 to 22 had a volume resistance value of less than 10 × 10 ⁻³ Ω · cm and exhibited excellent conductivity. The conductive adhesives of Examples 1 to 22 were all excellent in heat resistance and adhesiveness, prevented sedimentation and bleeding, had good conductivity stability, and were excellent in dischargeability. .
On the other hand, as shown in Table 8, in Comparative Examples 1 to 5, the volume resistance value was 10 × 10 ⁻³ Ω · cm or more, which was insufficient for applications requiring a low resistance value. Moreover, in Comparative Examples 1, 2, and 4, since the conductivity was insufficient and unstable, there was a problem that the measured value fluctuated during the measurement of the resistivity. Further, as shown in Table 10, Comparative Examples 8 to 10 had a problem that the dischargeability was particularly bad. In Comparative Example 7, bleeding occurred, causing a problem of poor conductivity stability, and the flowability test after storage could not be performed.

Claims (4)

(A) The main chain skeleton is one or more selected from the group consisting of a polyoxyarlequin polymer, a saturated hydrocarbon polymer, and a (meth) acrylic ester polymer, and a crosslinkable silicon group An organic polymer having
(B) selected from the group consisting of silver powder containing the first silver powder (b1) and the second silver powder (b2), and (C) hydrophobic silica and hydrophilic silica hydrophobized by the surface treatment agent One or more silicas,
A conductive adhesive comprising:
The specific surface area of the first silver powder (b1) is 0.5 m ² / g or more and less than 2 m ² / g, the tap density is 2.5 to 6.0 g / cm ³ ,
The specific surface area of the second silver powder (b2) is 2 m ² / g or more and 7 m ² / g or less, the tap density is 1.0 to 3.0 g / cm ³ ,
The mixing ratio [(b1) / (b2)] of the (b1) and the (b2) is 1/10 to 10/1 by mass ratio,
The (B) silver powder is 65% by mass or more and 85% by mass or less of the total content,
The conductive adhesive is characterized in that the surface treatment agent is at least one selected from the group consisting of dimethyldichlorosilane, hexamethyldisilazane, (meth) acrylsilane, octylsilane, and aminosilane.   2. The conductive adhesive according to claim 1, wherein the conductive adhesive is used for joining a semiconductor element, a chip part, a discrete part, or a combination thereof.   2. The conductive adhesive according to 1, which is used for bonding a crystal resonator or a piezoelectric element.   A circuit in which a semiconductor element, a chip component, a discrete component, or a combination thereof is bonded using the conductive adhesive according to claim 1.