KR101757171B1 - Electro-conductive nano-carbon paste designed for filling and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a conductive nanocarbon paste for filling used for forming a very thick filling material in a certain frame through an injection method.
The present invention has the following effects.
That is, even if a very thick filling material is formed by injecting the material having a low specific resistivity value, which can be used as an electrode, into a predetermined frame, there is no crack or lifting phenomenon. Therefore, the present invention can be applied to an electrical component manufacturing method such as an ultra dust collector that enables electrical conduction between components densely arranged in a vertical structure.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive nano-carbon paste composition for filling,

The present invention relates to a conductive nanocarbon for filling which is used for forming a very thick filling material in a certain frame through an injection method in order to manufacture an ultra fine dust collector capable of electrical conduction between parts densely arranged in a vertical structure Paste.

The conductive carbon paste referred to in the present invention is different from the method for forming a coating film such as printing, coating, or coating, on the premise of a carbon paste used for forming a very thick filling material in a predetermined frame through an injection method do.

Recently, home appliances such as refrigerators, washing machines, and air purifiers have been continuously being made highly functional, and there is a trend of combining products in which one product functions as two or more products. As a result, the number of product component parts is rapidly increasing. Therefore, the necessity of miniaturization and integration of components in a limited space and the three-dimensional space arrangement are continuously increasing. To this end, parts of precision electronic appliances Integration technologies are continuously being applied to the field of consumer electronics.

Conductive paste, which is one of the integrated parts of small products, is an example applied to the integration of household appliances. It replaces pcb board through printed circuit film, eliminates the physical switch button, and allows the three- In addition, it enables the densification of structures through vertical joining of parts, and it plays a role in the field of component integration of household appliances with various applicability.

In the production of electronic parts, conductive paste can be applied when dozens of components are vertically fixed parallel to each other to make a current flow. For example, the components are integrated in a tray-shaped frame having a predetermined size and depth, fixed with a temporary fixing device, and then a conductive paste composition is injected into the frame and fixed firmly through a curing process. And how to do it. In this case, the conductive paste should have a hard fill material of a certain thickness or more after curing, and should have low resistance and no cracking.

Conductive pastes are generally prepared by mixing a conductive material into a binder resin composition. The binder resin composition may be used alone as a binder resin, or may be prepared by dissolving it in an aqueous or oil-based liquid, and may include additives and the like. Examples of conductive pastes include metal pastes using metal powders such as silver, copper, and nickel, and carbon pastes using carbon-based powders such as carbon black, graphite, carbon nanotubes, and graphene depending on the type of conductive material. The metal paste has a low resistance and excellent physical properties, but it has a high price. On the other hand, carbon paste has problems such as cracking and high resistance, so it is very limited in use, but has a very high price. Therefore, if the physical properties are improved Its applicability is very high.

Typical carbon paste consists mainly of carbon powder, polymer resin, additive, and solvent. When the carbon paste of this general structure is applied to the injection type filling method and formed into a thick fill material, most of the cracks are generated. This is because of the high surface energy of the carbon powder, which leads to agglomeration during the curing process. Cracks lead to defective energization of the filler itself and poor contact with the parts. If the amount of the binder resin is too high as compared with the carbon powder, the crack can be reduced, but the resistance becomes very high and the function as an electrode can not be sufficiently exhibited.

In order for the carbon paste to function as an electrode, a resistivity of at least 10 ^-2 Ω · cm or less is required, and if it is higher than this, there may be a problem of restriction due to high resistance such as resistance heat generation and electrical signal incompatibility. For smooth filling, the paste should be basically flowable, and a certain amount of binder resin is necessary for this purpose. Therefore, when it is made into a paste, the resistivity of the raw material is greatly increased. Resistivity that can be secured when making a flowable paste with carbon powder is up to 10 ^-2 Ω · cm, and when it is tried to lower it, the flowability disappears or cracks occur.

In the case of a solvent-free paste which is not in the form of being dried by evaporating the solvent, there is no volume shrinkage due to solvent evaporation, which is advantageous in generating cracks. However, a large amount of resin is required to secure the flow characteristics of the paste, .

As described above, in the case of the carbon paste, there is a great difficulty in securing a composition that satisfies both of the two items of the crack and the resistivity which have a trade-off relationship in terms of mixing ratio of the binder resin and the carbon powder.

Open Patent No. 10-2016-0106050 (2016.09.09.)

Problems to be solved by the present invention are as follows.

That is, the present invention proposes a conductive nano carbon paste composition for filling which has a low specific resistivity value which can be used as an electrode, and which does not cause cracking or lifting even when a very thick filler is formed by injecting into a certain frame.

In order to solve the above problems,

(A), wherein 190 to 330 parts by weight of carbon powder, 40 to 80 parts by weight of metal powder, and 1 to 10 parts by weight of powder binder, based on 100 parts by weight of the polymer resin, 0.2 to 2 parts by weight of an additive, and 200 to 400 parts by weight of a solvent (A). The carbon powder is selected from two or more of carbon black, graphite and carbon nanotubes. Wherein the powdery binder is a polycarboxylic acid alcoholamine salt compound, wherein the polycarboxylic acid compound having a multivalent carboxyl group and an alcoholamine compound containing an alcohol group are dissolved in a solvent (B) Wherein the reaction product is prepared in the form of an opacifying solution by an equivalent reaction in the presence of a base.

The carbon powder is composed of 40 to 80 parts by weight of carbon black and 150 to 250 parts by weight of graphite powder. The carbon black and graphite powder have an oil absorption of 100 to 200 ml / 100 g. The polymer resin has a molecular weight of 5000 to 100000 g / mol and a glass transition temperature of 20 to 40 DEG C, or a conductive carbon black

A first step of completely dissolving the polymer resin while stirring the polymer resin into an agitator to which the solvent (A) is added for 5 hours; A second step of adding a powder binder and stirring for 30 minutes; A third step of adding metal powder and stirring for 1 hour; A fourth step of adding carbon powder and stirring for 1 hour; And a fifth step of adding the additive and stirring for 1 hour. The composition ratio of the material to be added is 190 to 330 parts by weight of carbon powder, 40 to 80 parts by weight of metal powder, 1 to 10 parts by weight of powder binder, 0.2 to 2 parts by weight of an additive, and 200 to 400 parts by weight of a solvent (A). The powdery binder in the second step is a polycarboxylic acid alcoholamine salt compound. The polybasic acid- Characterized in that the carboxylic acid compound and the alcohol amine compound containing an alcohol group are reacted in an equimolar manner in a solvent (B) to prepare an aqueous suspension having a concentration of 5 to 15% by weight,

The powdery binder in the second step may be prepared by adding a polycarboxylic acid compound into a solvent (B) in which one or more selected from alcohol, ketone, ester, and ether is mixed, and then adding 30 And the mixture is stirred for 1 hour to completely dissolve the mixture. Then, the mixture is stirred for 1 hour to give an alcohol-amine in an amount equivalent to an acid-base equivalent. The resultant mixture is made into a suspension having a concentration of 5-15 wt% A method for producing a carbon paste composition is presented.

The present invention has the following effects.

That is, even if a very thick filling material is formed by injecting the material having a low specific resistivity value, which can be used as an electrode, into a predetermined frame, there is no crack or lifting phenomenon. Therefore, the present invention can be applied to an electrical component manufacturing method such as an ultra dust collector that enables electrical conduction between components densely arranged in a vertical structure.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a flow chart of a method for manufacturing a conductive nanocarbon paste composition for filling according to the present invention. FIG.
FIG. 2 is a photograph of the filling material shape according to the embodiments (a, b, c) and the comparative examples (d, c) according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. However, the scope of the present invention should be understood from the description of the claims. Further, the description of known technology which obscures the gist of the present invention is omitted.

The carbon paste composition according to the present invention comprises carbon powder, metal powder, powder binder, polymer resin, additive and solvent (A).

The carbon powder may be selected from carbon black, graphite, carbon nanotubes, graphene, and the like.

In the case of carbon black, any of carbon powders which can be used not only in manufacturing methods such as channel black (chennel black), furnace black, thermal black and the like, and whose surface characteristics are acidic, neutral and basic And it is preferable to use a carbon powder having an oil absorption of at least 100 ml / 100 g or more. Carbon powders having an oil absorption of less than 100 ml / 100 g do not provide sufficient electrical conductivity when producing a paste.

In the case of graphite, any graphite powder produced not limited to natural graphite or artificial graphite can be used.

Carbon nanotubes can be used in any form, such as single wall, multiwall, etc.

When carbon black alone is used as the carbon black, the resistance is low, but the cracks are the greatest. When the graphite powder is used alone, the cracks are small and resistance is high. When the carbon black is used alone, the content can not be increased. It is hard to get thick fillings. Therefore, it is preferable to mix two or more of them appropriately.

The metal powder may be any of conductive metals such as silver, copper, nickel, aluminum, and silver-coated copper, and may be any shape such as spherical, acicular or laminar. .

Wherein the powder binder is a polycarboxylic acid alcoholamine salt compound, wherein a polycarboxylic acid compound having a polyvalent carboxyl group and an alcoholamine compound containing an alcohol group are reacted in an equivalent (B) And reacted to prepare a suspension in the form of a suspension.

The polycarboxylic acid compound and the alcohol amine compound may be subjected to an acid-base reaction in a separate solvent (B) in the form of a polycarboxylic acid-alcohol amine salt compound suspension.

The polycarboxylic acid compound may be selected from the group consisting of citric acid, isocitric acid, hemimellitic acid, trimellitic acid, prehnitic acid, benzenepentacarboxylic acid, wherein the organic acid is at least one selected from the group consisting of an acid, a mellitic acid, a trimesic acid, a pyromellitic acid, an iminodiacetic acid, a nitrilotriacetic acid, a pentetic acid, Ethylene glycol diamine tetraacetic acid, and the like.

The alcohol amine compound may be at least one selected from the group consisting of triethanolamine, diethanolamine, monoethanolamine, diethylethanolamine, dimethylethanolamine, ethyldiethanolamine, At least one alcohol amine selected from the group consisting of methyldiethanolamine, triisopropanolamine, diisopropanolamine, and the like.

The polycarboxylic acid-alcohol amine salt compound suspension may be prepared by adding a polycarboxylic acid compound into a solvent (B) in which one or more selected from among alcohols, ketones, esters, ethers, The reaction mixture was stirred for 30 minutes at a temperature of 0 ° C to completely dissolve the reaction mixture. The reaction mixture was stirred for 1 hour to give an acidic base equivalent of an alcohol amine. When the temperature is lower than 40 ° C, the polycarboxylic acid is not sufficiently dissolved. When the temperature is higher than 60 ° C, the alcohol amine is evaporated and the equivalent reaction can not proceed. The reaction time is preferably at least 1 hour, and the reaction is not sufficiently completed before 1 hour. The concentration of the polycarboxylic acid-alcohol amine salt compound in the solvent (B) is preferably 5 to 15% by weight. If it is less than 5% by weight, the yield is not as low as that of water, and if it is more than 15% by weight, the produced fine particles are excessively large in size, and the effect as a binder is deteriorated.

The polymer resin may be a mixture of one or more resins which are soluble in a solvent (A) such as alkyd, acrylic, polyester, polyurethane, polyvinyl alcohol, polyvinylpyrrolidone, etc. and have a viscosity. The resin having a molecular weight of 5000 to 100000 g / mol is preferable, and when it is lower than 5000 g / mol, the viscosity of the resin solution dissolved in the solvent (A) is low and the flowability of the carbon paste is not given. , The solubility in the solvent (A) is low and it is difficult to prepare the resin liquid. Further, a resin having a glass transition temperature of 20 DEG C or higher is preferable, and when it is less than that, the hardness of the cured filler is low and it is difficult to firmly fix the component.

The additive may be selected from one or more selected depending on the application and purpose, such as antifoaming agent, defoaming agent, leveling agent, base wetting agent, dispersant, flow control agent,

The solvent (A) may be any solvent that can dissolve the binder resin selected above.

In forming the carbon paste composition, the composition ratio of each component is preferably 40 to 80 parts by weight of carbon black, 150 to 250 parts by weight of graphite powder, 40 to 80 parts by weight of metal powder, 1 to 10 parts by weight of powder binder 0.2 to 2 parts by weight of a leveling agent, and 200 to 400 parts by weight of a solvent (A).

As shown in FIG. 1, the carbon paste composition of the present invention is prepared at room temperature. The polymer resin is added to a stirrer charged with the solvent (A) and stirred for 5 hours to completely dissolve the polymer resin Stage 1; A second step of adding a powder binder and stirring for 30 minutes; A third step of adding metal powder and stirring for 1 hour; A fourth step of adding carbon powder and stirring for 1 hour; And the fifth step of adding the additive and stirring for 1 hour.

At this time, the powder binder of the second stage may be prepared by adding a polycarboxylic acid compound into a solvent (B) in which one or more selected from alcohol, ketone, ester, The mixture was completely dissolved by stirring at a temperature for 30 minutes, and an alcohol amine in an amount equivalent to an acid-base equivalent was added thereto, followed by stirring for 1 hour to prepare an opaque liquid in which white fine particles were formed.

( Example  One)

1. Manufacture of powder binder suspension

 Solvent (B): 30 g of 2-methoxyethanol

 - Polycarboxylic acid: 2 g of trimellitic acid

 - Alcohol amine: Monoethanol amine 1.8 g

2 g of trimellitic acid was added to 30 g of 2-methoxyethanol, the temperature was maintained at 50 DEG C, and the mixture was stirred and dissolved for 30 minutes. 1.8 g of monoethanolamine was slowly added thereto under stirring, and the mixture was stirred at 50 캜 for 1 hour to obtain a white powdery binder suspension.

2. Manufacture of carbon paste

 Solvent (A): Monoethanolamine 1.8 g

 - Polymer resin: 100g of acrylic resin

 - Powder binder: Powder binder 33.8g

 - metal powder: copper powder 60g

 - Carbon powder: 200g of graphite powder and 100g of carbon black

 - Additive: Leveling agent 1g

100 g of acrylic resin was added to 300 g of 2-methoxyethanol, and the mixture was stirred and dissolved for 5 hours. To this was added 33.8 g of the powder binder suspension prepared above, stirred for 30 minutes, 60 g of copper powder was added with stirring, and the mixture was stirred for 1 hour. Thereafter, 200 g of graphite powder and 100 g of carbon black were sequentially added, and the mixture was stirred at room temperature for 1 hour. Then, the leveling agent (1 g) was added and stirred at room temperature for 1 hour to obtain a uniform paste. In the stirring step, the stirring speed is maintained at 100 rpm.

( Example  2)

1. Manufacture of powder binder suspension

 Solvent (B): 40 g of 2-methoxyethanol

 - Polycarboxylic acid: pyromellitic acid 2 g

 - Alcohol amine: triethanolamine 4.8 g

2 g of pyromellitic acid was added to 40 g of 2-methoxyethanol, and the mixture was stirred for 30 minutes while maintaining the temperature at 50 캜. 4.8 g of triethanolamine was slowly added thereto under stirring, and the mixture was stirred at 50 캜 for 1 hour to obtain a white powdery binder suspension.

2. Manufacture of carbon paste

 Solvent (A): 300 g of 2-methoxyethanol

 - Polymer resin: 100g of acrylic resin

 - Powder binding agent: Powder binding agent cloudy solution 46.8g

 - metal powder: copper powder 60g

 - Carbon powder: 200g of graphite powder and 100g of carbon black

 - Additive: Leveling agent 1g

100 g of acrylic resin was added to 300 g of 2-methoxyethanol with stirring and the mixture was stirred and dissolved for 5 hours. To this was added 46.8 g of the powder binder suspension prepared above, stirred for 30 minutes, 60 g of copper powder was added with stirring, and the mixture was stirred for 1 hour. 200 g of graphite powder and 100 g of carbon black were sequentially added, and the mixture was stirred at room temperature for 1 hour. Then, a leveling agent (1 g) was added and stirred at room temperature for 1 hour to obtain a uniform paste. In the stirring step, the stirring speed is maintained at 100 rpm.

( Example  3)

The procedure of Example 1 was repeated except that 60 g of silver-coated copper powder was used instead of 60 g of copper powder.

( Comparative Example  One)

The procedure of Example 1 was repeated except that the powder binder suspension was not added in Example 1.

( Comparative Example  2)

The procedure of Example 1 was repeated except that the powder binder suspension and the copper powder were not added in Example 1.

Table 1 below is a table showing the composition of the conductive carbon paste composition according to each of Examples and Comparative Examples.

Furtherance Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Polymer resin 100 100 100 100 100 Graphite powder 200 200 200 200 200 Carbon black 100 100 100 100 100 Metal powder 60 60 60 60 - Powder binder suspension 33.8 46.8 33.8 - - Leveling agent One One One One One solvent 300 300 300 300 300

Polymer resin: B44, Paraloid

Graphite powder: impression graphite, Hyundai coma industry

Carbon black: Chezacarb AC-30, Unipetrol

Metal powders: Cu, Ag-coated Cu, Ames Goldsmith

Leveling agents: BYK-306, BYK

( Experimental Example )

(1) Resistivity: It is applied by film casting method, and then it is cured at 60 ℃ for 1 hour and converted to resistivity by measuring film thickness and surface resistance.

(2) Inspection of the shape of the filler: Charge about 10 g of carbon paste into a plastic frame having a length of 250 mm, a width of 20 mm and a depth of 5 mm, and then cure at 60 ° C for 2 hours to visually observe the presence of cracks,

(3) Fill resistance: The end-to-end resistance of the filling material formed in the same frame is measured with a 2-point tester.

2 is a graph showing the physical properties of the conductive carbon paste prepared through the above examples and comparative examples, and FIG. 2 is a photograph of the shape of the filler (FIG. 2 (a) (C) of Example 3, (d) of Comparative Example 1, and (e) of Comparative Example 2).

Properties Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Resistivity (Ωcm) 3.8 × 10 ^-2 4.4 × 10 ^-2 1.3 x 10 ^-2 8.7 x 10 ^-2 4.2 x 10 ^-1 Filler resistance (Ω) 5.2 6.5 1.4 85 460 Fill shape Good Good Good Cracking Cracking

In comparison of each of Examples and Comparative Examples physical properties, the resistivity of all 10 ^{- 2} Ω · while a carbon paste satisfies a condition to serve as an electrode as a cm or less, an example compared to the embodiment in the resistance to the shape characteristics of the filling It can be confirmed that there is a clear difference.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be clear to those who have knowledge.

Claims (4)

A carbon powder, a metal powder, a powder binder, a polymer resin, an additive and a solvent (A)
(A) in a composition ratio of 190 to 330 parts by weight of carbon powder, 40 to 80 parts by weight of a metal powder, 1 to 10 parts by weight of a powder binder, 0.2 to 2 parts by weight of an additive, and 200 to 400 parts by weight of a solvent (A)

The carbon powder is selected from two or more of carbon black, graphite, and carbon nanotubes,
The polymer resin is dissolved in the solvent (A) to have a viscosity,
The powder binder
As polycarboxylic acid-alcoholamine salt compounds,
A polycarboxylic acid compound having a polyvalent carboxyl group and an alcohol amine compound containing an alcohol group
(B) in the form of an opacifying solution.
Conductive carbon paste composition for filling.
The method according to claim 1,
The carbon powder is composed of 40 to 80 parts by weight of carbon black and 150 to 250 parts by weight of graphite powder,
Carbon black and graphite powder have an oil absorption of 100 to 200 ml / 100 g,
Wherein the polymer resin has a molecular weight of 5,000 to 100,000 g / mol and a glass transition temperature of 20 to 40 ° C
Conductive carbon paste composition for filling.
A first step of completely dissolving the polymer resin while stirring the polymer resin into an agitator to which the solvent (A) is added for 5 hours;
A second step of adding a powder binder and stirring for 30 minutes;
A third step of adding metal powder and stirring for 1 hour;
A fourth step of adding carbon powder and stirring for 1 hour;
And a fifth step of adding an additive and stirring for 1 hour,
The composition ratio of the input material is
(A) is 200 to 400 parts by weight based on 100 parts by weight of the polymeric resin, 190 to 330 parts by weight of carbon powder, 40 to 80 parts by weight of a metal powder, 1 to 10 parts by weight of a powder binder, 0.2 to 2 parts by weight of an additive,

The powder binder of the second step
As polycarboxylic acid-alcoholamine salt compounds,
A polycarboxylic acid compound having a polyvalent carboxyl group and an alcohol amine compound containing an alcohol group
(B) in an amount equivalent to 5 to 15% by weight.
A method for manufacturing a conductive carbon paste composition for filling.
The method of claim 3,
The powder binder of the second step
(B) in which at least one alcohol-based, ketone-based, ester-based or ether-based solvent is selected and mixed
After adding the polycarboxylic acid compound
The mixture was stirred at a temperature of 40 to 60 DEG C for 30 minutes to dissolve completely,
After the addition of the amount of alcohol amine weighed in acid-base equivalents
And stirring the mixture for 1 hour to prepare a suspension having a concentration of 5 to 15% by weight at which white fine particles are produced
A method for manufacturing a conductive carbon paste composition for filling.

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