KR20010096594A - Conductive Ink Compositions - Google Patents

Abstract

PURPOSE: To provide an electroconductive ink composition that makes it difficult to allow separation of an electroconductive filler therefrom caused by a solvent, exfoliation of a film thereof caused by rubbing, etc. CONSTITUTION: This electroconductive ink composition comprises (A) a liquid hydrocarbon polymer comprising a divalent hydrocarbon group repeating unit wherein both molecular ends are blocked with hydrolyzable silyl groups and its main molecular chain may contain an oxygen atom and/or a siloxane bond, (B) a curing catalyst, (C) a carbonaceous electroconductive filler and (D) a solvent.

Description

Conductive Ink Compositions

TECHNICAL FIELD The present invention relates to a conductive ink composition and a cured product which are excellent in electrical conductivity and do not cause separation of a carbon filler by a solvent, and which are excellent in friction resistance when a cured film is formed.

As the conductive ink composition, a conductive ink composition in which carbon powder, metal powder, or metal oxide powder is blended with a room temperature curable or addition curable organopolysiloxane composition as a conductive filler to impart conductivity to the cured product (silicone rubber), This is used as a top coating material of a keyboard, for example.

However, when a conductive ink composition having a high filling of such a conductive filler in a composition having an organopolysiloxane as a base polymer is diluted with a solvent, the conductive filler is likely to be separated from the organopolysiloxane. In addition, if the film obtained by hardening this as a top coating material is rubbed strongly, the cured film is peeled off from the surface of the keyboard base material and adheres to the vicinity of the rubbed portion, thereby damaging the appearance.

Therefore, an object of the present invention is to provide a conductive ink composition in which separation of the conductive filler with a solvent, peeling due to friction, and the like are unlikely to occur.

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining about a conductive ink composition,

(A) a hydrocarbon-based liquid polymer in which the sock end is sealed with a hydrolyzable silyl group and the main chain includes a divalent hydrocarbon group repeating unit which may include an oxygen atom and / or a siloxane bond,

(B) curing catalyst,

(C) a carbon-based conductive filler, and

(D) solvent

It has been found that the above-described problems can be solved by the conductive ink composition, which contains.

The present invention is described in detail below.

Component (A) is a liquid polymer in which the end is blocked with a hydrolyzable silyl group and the main chain comprises a divalent hydrocarbon group repeating unit which may contain an oxygen atom and / or a siloxane bond.

Thus, since the polymer (A) which is the base polymer of the present invention is a hydrocarbon-based polymer such as polyolefin and polyether, the separation of the carbon-based conductive filler by the solvent is suppressed in the composition state, and after curing to a film form, Peeling is suppressed. This is because polyolefin or polyether constituting the main chain has good affinity with the carbon-based conductive filler and good affinity with the carbon-based solvent generally used as the diluent solvent.

Examples of the divalent hydrocarbon group to be the repeating unit of the main chain include those having 2 to 20 carbon atoms, and for example, arylene groups such as alkylene groups such as ethylene group, propylene group, isopropylene group, and isobutylene group, and phenylene group. , Combinations thereof, and specifically, for example

Etc. are mentioned, Preferably they are C2-C8. The polymer chain may be formed by one type of these unit structures alone, or may be formed in a form in which two or more types of unit structures are mixed.

Moreover, as a bivalent hydrocarbon used as a repeating unit of a main chain, the alkyleneoxy group of 2 or more carbon atoms is mentioned, As a specific example of this alkyleneoxy group,

Etc. can be mentioned.

When the main chain does not contain a siloxane bond, an oxyalkylene group is preferable, and an oxyalkylene group having 2 to 8 carbon atoms, particularly 2 to 5 carbon atoms is preferable. Especially, group of following General formula (1) is preferable.

The main chain constituted from these repeating units is bonded directly or via a divalent hydrocarbon group such as an ethylene bond or a propylene bond to the terminal hydrolyzable silyl group. When these main chains do not contain a siloxane bond, it is preferable that they are 200-50,000, especially 1,000-30,000. When molecular weight exceeds 50,000, it may become a solid or workability may fall. In addition, the "liquid phase" of this component means having fluidity at room temperature.

In addition, by introducing a siloxane bond into the repeating unit of the main chain can be made into a liquid phase even at a higher molecular weight, and at the same time improve the weather resistance or heat resistance. In this case, when the siloxane bond introduced into the repeating unit is too long, the conductive filler is likely to be separated, and therefore, the siloxane bond to be introduced is preferably short, particularly a siloxane bond having 5 or less silicon atoms, and the unit represented by the following general formula (2) Is preferred.

Wherein R ¹ is the same or different and is a monovalent hydrocarbon group or a halogenated hydrocarbon group. Specifically

(R ² is a divalent hydrocarbon group which may contain an oxygen atom), more specifically

Etc. are illustrated.

In the case where siloxane bonds are introduced, the number (polymerization degree) of the repeating units is preferably 1 to 10,000, particularly 2 to 200.

In the case where a siloxane bond is introduced, the main chain is also bonded to the terminal hydrolyzable silyl group directly or through a divalent hydrocarbon group which may contain an oxygen atom, as in the case where no siloxane bond is introduced.

The terminal hydrolyzable silyl group is represented by the following general formula (3).

In the formula, R ³ is the same or different monovalent hydrocarbon group or halogenated hydrocarbon group, X is a hydrolyzable group, and a is an integer of 0 to 2. As a hydrolyzable group, an alkoxy group, a ketoxime group, a halogen atom, an acetoxy group, an amino group, an aminooxy group, an alkenyloxy group, an amide group, etc. are illustrated, Alkoxy group, an alkenyloxy group, a ketooxime group is preferable. a is preferably O or 1;

(B) curing catalyst

As the curing catalyst, any one known as a silanol condensation catalyst can be used. Representatives include, for example, alkyl titanates: metal carboxylates such as organosilicon titanates, octylic acid tin, dibutyl tin phthalate and the like, amine salts such as dibutylamine-2-ethylhexate and the like, and other acidic catalysts and basic And nitrogen-containing compounds having a guanidyl group, in particular. Usually, these may be used individually by 1 type and may be used together 2 or more types. In the case where the hydrolyzable group X in the formula (4) is an alkoxy group, carboxylate salt of tin is particularly preferable.

The amount of the condensation catalyst may be usually 0.1 to 10 parts by weight, preferably 0.1 to 3 parts by weight, per 100 parts by weight of the component (A).

(C) carbon-based conductive filler:

Carbon-based conductive fillers act as conductivity imparting agents in this composition. For example, acetylene black, fines black, thermal black, lamp black, channel black, carbon fiber, graphite and the like are exemplified. When using these, you may use individually by 1 type and can use 2 or more types together.

It is preferable to make the compounding quantity with respect to 100 weight part of (A) component of this (C) component normally in the range of 5-500 weight part, More preferably, it is the range of 15-50 weight part. When the compounding quantity of the said component is too small, the electroconductivity obtained may be inadequate, and when too large, the discharge property by the extruder of the composition obtained may fall, and it is unpreferable.

(D) solvent

Solvents are used for the purpose of improving the flowability or wettability of the composition. Examples of the solvent used may include aromatic hydrocarbon solvents such as toluene and xylene, aliphatic hydrocarbon solvents such as hexane and heptane, halogenated hydrocarbon solvents such as dichloromethane and carbon tetrachloride, and ketone solvents such as acetone and methyl ethyl ketone. Especially, aromatic hydrocarbon solvents, such as toluene and xylene, are preferable.

This (D) component should just be a suitable quantity from which required fluidity | liquidity or wettability are acquired. Specifically, the range of 1 to 900 parts by weight is preferable with respect to 100 parts by weight of the total of the components (A) to (C), and more preferably 100 to 500 parts by weight.

Other ingredients

You may mix | blend another component with the composition of this invention as needed. For example, an adhesion | attachment adjuvant, a crosslinking agent, a filler, a plasticizer etc. are mentioned. Although the composition of this invention hardens | cures even without adding a crosslinking agent, you may use a crosslinking agent in order to accelerate hardening. As a crosslinking agent, the silane compound which has three or four hydrolysable groups in 1 molecule, or its partial hydrolyzate is illustrated.

It is preferable to add an adhesion | attachment adjuvant, and it is preferable to mix | blend 0.1-10 weight part with respect to 100 weight part of (A) component. As an adhesion | attachment adjuvant, a silane coupling agent or a titanium type coupling agent is illustrated, A silane coupling agent is preferable. As the silane coupling agent, an amino silane coupling agent, an epoxy silane coupling agent, a methacryl silane coupling agent, a mercapto silane coupling agent are preferable, and an amino silane coupling agent is particularly preferable.

Examples of the filler include reinforcing fillers such as fumed silica, precipitated silica, silicic anhydride, hydrous silicic acid, calcium carbonate, magnesium carbonate, diatomaceous earth, calcined cray, cray, talc, titanium oxide, bentonite, organic bentonite, ferric oxide, Fillers such as zinc oxide, activated zinc, silas balloon and the like can be used. If such a filler is added in a large amount, the conductivity may be impaired. Thus, the amount of the filler is formulated to such an extent that such harmful effects do not occur. Usually, about 5-20 weight part is preferable per 100 weight part of polymers of (A) component.

When used together with a filler, the plasticizer is effective for increasing the elongation of the cured product or increasing the amount of the filler. As the plasticizer, one that is commonly used can be used, and for example, phthalic acid esters such as dioctyl phthalate, dibutyl phthalate, butyl benzyl phthalate, aliphatic dibasic, adipic acid dioctyl, isodecyl succinate, dibutyl sebacinate and the like Esters, glycol esters such as diethylene glycol dibenzoate, pentaerythritol esters, aliphatic esters such as butyl oleate, methyl acetyl ricinoleate, phosphate esters such as tricresyl phosphate, trioctyl phosphate, octyl diphenyl phosphate, etc. Epoxy plasticizers such as epoxy, soybean oil, benzyl epoxy stearate and the like; Plasticizers, such as chlorinated paraffin, are mentioned. These can be used individually or in the form which combined 2 or more types. It is preferable to add a plasticizer below 100 weight part normally with respect to 100 weight part of polymers of (A) component.

Usage and purpose

The composition of the present invention can be prepared in any one of a one-component composition and a two-component composition. When using as a two-component composition, it may divide into a pack which consists of a polymer of a (A) component, a filler, and a plasticizer, and a pack which consists of a plasticizer and a condensation catalyst, for example, and may mix and use the components of both packs just before use. When using as a one-component composition, it is good to enclose and store in the container which can maintain anhydrous states, such as a cartridge, in the state which mixed all the components, and to take out from a container at the time of use, and to use. The composition of the present invention is particularly useful as one-component and two-component conductive inks.

When forming the cured film of thickness 1mm or less using the composition of this invention, although it can harden | cure at room temperature, when it heats at 70 degreeC or more, it hardens rapidly in about 20 minutes, and the film excellent in electroconductivity is obtained.

Next, although an Example demonstrates this invention, what is called a part in an Example means a weight part and a viscosity is a value in 23 degreeC. In addition, surface resistance was measured with the surface resistance measuring instrument (Hewlett-Packard company make, brand name multimeter E2378A). In addition, the dispersibility at the time of dissolving in a solvent observed and measured visually.

<Example 1>

100 parts of terminal silane-modified polyethers represented by the following formulas obtained by addition reaction of propylene glycol whose molecular weight is 5000 and the sock end is terminated with an allyl group, and methyldiisopropenoxysilane under a platinum catalyst, and conductive carbon black (Denki Chemical) High school products, brand name: Denka black HS-100) 35 parts, dibutyldimethoxytin 1 part, tetramethylguanidylpropyltrimethoxysilane 1 part, aminopropyltrimethoxysilane 2 parts, vinyltriisopropenoxy A conductive ink composition was obtained by mixing 2.5 parts of silane and 300 parts of xylene (viscosity 2 Pa · s, nonvolatile content: 30%).

<Example 2>

By reacting 134 g of tetramethyldisiloxane and 135 g of divinylbenzene under a platinum catalyst, a polymer in which the sock end represented by the following formula was stopped with a vinyl group was obtained. 4.7 g of trimethoxysilane was added dropwise to this polymer to further react to obtain a terminal silane-modified polymer. To 100 parts of this polymer, 35 parts of conductive carbon black (manufactured by Denki Chemical Co., Ltd., product name Denka Black HS-100), 1 part of dibutyldimethoxytin, 2 parts of aminopropyltrimethoxysilane, and vinyltrimethoxysilane A conductive ink composition was obtained by mixing 2.5 parts and 300 parts of xylene. (Viscosity 5 Pa.s, nonvolatile content: 30%)

<Example 3>

100 parts of terminal silane-modified polyethers represented by the following formulas obtained by addition reaction of poly 1,4-butylene glycol and methyldiisopropenoxysilane, which have a molecular weight of 5000 and stop the sock end with an allyl group, under a platinum catalyst, and conductivity 35 parts of carbon black (Denki Chemical Co., Ltd. make, brand name: Denka black HS-100), 1 part of dibutyl dimethoxy tin, 2 parts of aminopropyl trimethoxysilane, 2.5 parts of vinyl triisopropenoxysilane, xylene 300 The parts were mixed to obtain a conductive ink composition. (Viscosity 2 Pa · s, nonvolatile content 30%)

Comparative Example 1

100 parts of polydimethylsiloxane in which the molecular weight represented by the following chemical formula is 33000 and the sock end is stopped by a vinyl group, 25 parts of conductive carbon black (manufactured by Denki Chemical Co., Ltd., product name: Denka Black HS-100), platinum acid (2%) A conductive ink composition was obtained by mixing 0.08 parts of a 2-ethylhexanol solution, 0.2 parts of tetramethylvinylcyclotetrasiloxane, 1 part of α, ω-trimethylsilylpolymethylhydrogensiloxane (molecular weight: 700) and 300 parts of xylene ( Viscosity 10 Pa · s, nonvolatile content 30%).

Comparative Example 2

100 parts of polydimethylsiloxane in which the molecular weight represented by the following formula is 33000 and the sock end is stopped with a silanol group, 25 parts of conductive carbon black (manufactured by Denki Chemical Co., Ltd., product name: Denka Black HS-100), dibutyldimethoxy tin A conductive ink composition was obtained by mixing 0.1 part, 1 part of aminopropyltrimethoxysilane, 4 parts of vinyltriisopropenoxysilane, and 300 parts of xylene. (Viscosity 10 Pa.s, nonvolatile content 30%)

<Dispersibility Evaluation of Conductive Carbon Black>

The five kinds of compositions prepared in the above-described Examples and Comparative Examples were left to stand for one month from preparation, and visually observed whether carbon black aggregates were formed on the wall of the container and evaluated. The results are shown in Table 1. In addition, the meaning of (circle) and (x) is as follows.

○: no aggregation on the container wall

×: agglomeration on the container wall

<Frictional Resistance Evaluation>

The composition was apply | coated on Shin-Etsu Chemical Co., Ltd. product KE951, and it heated and hardened at 100 degreeC for 30 minutes. And the obtained hardened | cured material surface was rubbed repeatedly with the glass rod using the friction test machine, and the number of frictions until carbon black adheres to the said glass rod was measured.

<Test result>

Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Dispersibility of Carbon Black ○ ○ ○ × × Friction resistance More than 100 More than 100 More than 100 20 20

From the above results, it was found that the composition obtained in the present invention exhibits good dispersibility and also effectively inhibits separation of the conductive carbon black from the surface.

In the conductive ink composition of the present invention, separation of the conductive filler by the solvent occurs and is difficult, and peeling due to friction is less likely to occur when formed on the substrate in a film form. Therefore, it is also useful as a conductive coating forming material.

Claims (6)

(A) a hydrocarbon-based liquid polymer in which the sock end is sealed with a hydrolyzable silyl group and the main chain includes a divalent hydrocarbon group repeating unit which may include an oxygen atom and / or a siloxane bond, (B) curing catalyst, (C) a carbon-based conductive filler, and (D) solvent A conductive ink composition comprising a. The conductive ink composition according to claim 1, wherein the main chain comprises a repeating unit having an alkylene group or an oxyalkylene group having 2 to 8 carbon atoms. The conductive ink composition according to claim 2, wherein the main chain includes a repeating unit represented by the following general formula (1). <Formula 1> The conductive ink composition according to claim 1, wherein the main chain comprises a divalent hydrocarbon group repeating unit including a unit represented by the following formula (2). <Formula 2> In formula, R <^1> is the same or different and is a monovalent hydrocarbon group or a halogenated hydrocarbon group. The conductive ink composition according to any one of claims 1 to 4, wherein the terminal is an organosilyl group represented by the following formula (3). <Formula 3> In formula, R <^4> is the same or different, is a monovalent hydrocarbon group or a halogenated hydrocarbon group, X is group chosen from the group which consists of an alkoxy group, an alkenyloxy group, and a ketoxime group, and a is an integer of 0-2. Hardened | cured material obtained by hardening the composition as described in any one of Claims 1-5.