KR20180111259A - Conductive fiber assemblies comprising network-structured metal coating layer - Google Patents

Abstract

The present invention relates to a conductive fiber assembly, and more specifically, to a conductive fiber assembly which can exhibit excellent conductivity by having metal particles forming a dense network structure; and has improved inter-particle adhesion and the adhesion to a substrate, thereby showing excellent durability without containing a separate binder component.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a conductive fiber assembly comprising a metal of a network structure,

More particularly, the present invention relates to a conductive fiber aggregate, and more particularly, to a metal fiber aggregate which forms a network structure, so that metal particles form a dense structure and can exhibit excellent conductivity, To a conductive fiber aggregate having excellent durability without any separate binder component.

With the development of scientific civilization, the use of various electric, electronic and communication devices for the convenience of mankind is expanding. These devices cause the harmful effects of human life and the unwanted harmful factors simultaneously. In particular, electromagnetic waves generated from high-frequency electronic devices can adversely affect the human brain, and electromagnetic interference (EMI) with neighboring electronic devices may cause malfunction of electronic devices. In addition, when a human body is exposed to a microwave generated from a household electric appliance such as a microwave oven for a long time, it is reported that the human body is adversely affected by the heat of the microwave, resulting in serious consequences such as deterioration of reproductive ability.

In order to solve the damage of the electromagnetic wave, it is possible to shield the electromagnetic wave from the electronic device. A typical shielding product is a shielding paint, which is a product obtained by mixing metals such as Ni and Cu or a conductive material with a polymer material, and Korean Laid-Open Publication No. 2015-0077238 discloses a coating composition for shielding electromagnetic waves have. However, the disadvantage is that the thickness of the coating is relatively thick due to the high resistance as compared with the plating and vapor deposition methods, and there is a problem in the deterioration and uniformity of the coating film and the long-term shielding effect due to oxidation is inferior. Recently, as the harmful effects of electromagnetic waves are known, regulations for allowing electromagnetic waves in each country have become strict, and high performance of electromagnetic wave shielding coating agents is required. Background of the Invention In recent years, electromagnetic wave shielding materials have been actively developed to coat the surface of the metal to prevent oxidation of the metal and to improve the electrical conductivity, thereby exhibiting a good resistance value even at a low film thickness and exhibiting sufficient shielding efficiency.

On the other hand, the electromagnetic wave removing material can be directly coated on an object that emits electromagnetic waves, but this method requires a separate process for each part, which complicates the manufacturing process and increases the cost. Therefore, it is developed as a shielded component in a complex state by treating it with a separate support member. As the support member, a polymer film, a plastic, a fiber product, or the like is used. However, the polymer film has a limited amount of coverage as the area capable of covering the electromagnetic wave removing material is confined to the surface. In order to cover a large amount, , Which is undesirable in recent trends toward thinner and smaller size. In addition, the plastic has poor flexibility and tends to cause cracks, which may cause deterioration of electromagnetic wave shielding characteristics due to cracks. In addition, since the fabric material, for example, fabric, having the same thickness can provide a certain amount of electromagnetic wave removing material inside the film, it is advantageous to exhibit electromagnetic wave removing performance superior to that of the film. Also, the fabric may be woven into yarns comprising a plurality of strands of fibers, wherein the multiple strands of stranded fibers in the cross-section of the fabric may be more advantageous in terms of electromagnetic shielding as they form a multi-layer structure.

Electrolytic plating methods are applied to conductive fibers or fabrics. They are complicated and have a problem of pollution due to a large amount of wastewater. In addition, when the metal layer is formed in the form of a film, stress is applied to a part of the film or cracks occur.

On the other hand, metal ink used for metal circuit pattern formation is mostly dispersed with metal particles. At this time, sintering temperature is higher than 300 ° C. In order to lower the sintering temperature, a number of studies have been carried out to reduce the size of the metal to a nanosize size, which is expensive and requires additional steps to disperse the metal particles to form the ink.

Process conditions such as high temperature, pressure, etc., which are applied when forming the coating layer, have the problem of causing physical damage to the supporting member on which the coating layer is to be formed. Therefore, it is urgent to investigate a conductive fiber aggregate having excellent conductivity and durability under relaxed process conditions.

Korean Patent Publication No. 2015-0077238 Korean Patent No. 10-1252182 Japanese Laid-Open Patent Application No. 2004-119386

Disclosure of Invention Technical Problem [8] The present invention has been made to overcome the problems of the prior art as described above, and it is an object of the present invention to provide a method for producing a metal particle which can form a dense structure and exhibit excellent conductivity, To provide a conductive fiber aggregate having excellent durability even without a binder component.

Among them, in particular, the present invention is characterized by: (1) a sheet resistance of not more than 20? /? And (2) a conductive property capable of exhibiting resistance to peeling which is not transferred to the tape at all in the evaluation of peelability, Fiber aggregates.

The present invention also provides a conductive fiber aggregate having a low process temperature for imparting conductivity to the fibrous aggregate and free from physical or chemical damage to the substrate.

It is another object of the present invention to provide a coating composition which can be provided with a wide specific surface area and is excellent in coating properties on the outer and inner surfaces of the support member and exhibits excellent electromagnetic wave shielding performance and is excellent in durability An excellent conductive fiber aggregate, and various electronic parts and electronic apparatuses realized therefrom.

An aspect of the present invention is a conductive fiber aggregate comprising (a) a fibrous aggregate, and (b) a metal layer formed on the surface of the fibrous aggregate, wherein the metal layer has an average spheroidization ratio of 0.1 to 0.7, an average aspect ratio of 1.6 to 2.1, Wherein the conductive fiber aggregate has a porosity of 3% to 6%, and the conductive fiber aggregate has an organic amine residual amount of 0 to 300 ppm based on the total weight of the conductive fiber aggregate.

Another aspect of the present invention relates to a gasket, conductive tape or electronic device comprising a conductive fiber assembly according to various embodiments of the present invention.

The conductive fiber aggregate of the present invention has a network structure in which the metal particles form a dense structure and can exhibit excellent conductivity, and the adhesion between the particles and the substrate is improved, so that a separate binder component A conductive fiber aggregate having excellent durability can be provided.

In particular, the conductive fiber aggregate according to the present invention is characterized by: ① excellent conductivity having a sheet resistance of not more than 20 Ω / □, and ② resistance to peeling of the tape, which is not transferred to the tape at all in the evaluation of peel resistance performed using a tape according to the method described in the present invention Peelability can be exhibited.

In addition, the present invention provides a conductive fiber which is provided with a wide specific surface area and exhibits excellent electromagnetic wave shielding performance due to excellent coating properties on the outer and inner surfaces of the support member, And various electronic parts and electronic apparatuses realized therefrom can be provided.

1 is a SEM photograph of a conductive fabric produced according to Preparation Example using the copper precursor ink of Example 3;
Figs. 2A to 2E are images showing the image processing steps for analyzing the sphericalization ratio and the aspect ratio of the mouthpiece.

Hereinafter, various aspects and various embodiments of the present invention will be described in more detail.

An aspect of the present invention is a conductive fiber aggregate comprising (a) a fibrous aggregate, and (b) a metal layer formed on the surface of the fibrous aggregate, wherein the metal layer has an average spheroidization ratio of 0.1 to 0.7, an average aspect ratio of 1.6 to 2.1, Wherein the conductive fiber aggregate has a porosity of 3% to 6%, and the conductive fiber aggregate has an organic amine residual amount of 0 to 300 ppm based on the total weight of the conductive fiber aggregate.

That is, according to one aspect of the present invention, the metal layer constituting the conductive fiber aggregate has (1) an average spheroidization ratio of 0.1 to 0.7, (2) an average aspect ratio of 1.6 to 2.1, and (3) (1) to (6), and (4) the organic amine does not remain in the conductive fiber aggregate. If the above conditions (1) And (2) it was confirmed that the peel resistance, which is not transferred to the tape at all, can be achieved in the peel resistance evaluation performed using the tape according to the method described in the present invention.

As described in the peeling resistance evaluation method of the present invention is the experimental example mentioned above, one ㅧ 2cm and then attached to the conductive fiber aggregates produce a tape of the size after nulreun applying a force of 2kg _f, 1cm at an angle of 90 ^o / and the degree of peel resistance is evaluated by the ratio of the area of the evaluated area to the area transferred to the tape.

That is, when any one of the conditions (1) to (4) is not satisfied, it is confirmed that the above-mentioned effects (1) and (2) of the present invention can not be achieved.

According to one embodiment, the metal layer is formed by a metal salt reduction method.

According to another embodiment, the metal salt reduction method is carried out by reducing the metal salt precursor using an organic amine and a reducing agent.

In the present invention, the organic amine forms a complex with the copper ion so that the reduction can be performed at a low temperature. The size of the copper particles is determined by the number of carbon atoms of the organic amine. The larger the carbon number, the smaller the size of the particles. The smaller the particle size, the easier the sintering at a lower temperature. When an amine having a lower carbon number than the above-mentioned organic amine is used, there is a problem that sintering of the metal particles is not performed well and the particles are present in a state of being solitary so that conductivity and peeling resistance are lowered. If used, it remains unremoved in the heat treatment step, thereby lowering the conductivity.

According to another embodiment, the organic amine is at least one selected from the group consisting of a primary amine having 7 to 10 carbon atoms, a secondary amine having 3 to 6 carbon atoms, and a cyclic amine having 7 or 8 carbon atoms.

According to another embodiment, the organic amine and the reducing agent are used in a molar ratio of 1: 1 to 1: 2, preferably 1: 1 to 1: 1.7.

When the reducing agent is less than the above-mentioned molar ratio, there may be a problem that the metal complex is not reduced well. When the reducing agent is in excess of the above-mentioned molar ratio with respect to the organic amine, reduction of the metal ion occurs actively due to excessive reducing agent, The sintering between the particles is impeded and the sheet resistance and peel resistance may be deteriorated.

According to another embodiment, the metal is at least one selected from copper, nickel, silver, aluminum, cobalt and alloys of two or more of these metals.

According to another embodiment, the substrate is selected from fibers, fabrics, knits, and nonwovens.

According to another embodiment, the substrate may be a polyester resin, a polyamide resin, a polyethylene resin, a polypropylene resin, a polyvinyl chloride resin, a polyvinyl resin, a polytetrafluoroethylene resin, a polyvinyl alcohol resin A resin, a polyacrylonitrile resin, an aramid resin, an acrylic resin, and a polyurethane resin.

According to another embodiment, the reducing agent is selected from the group consisting of formic acid, acrylic acid, phosphoric acid, citric acid, lactic acid, alanine, glycolic acid, glycine, acetic acid, formaldehyde, hydrazine, sodium borohydride, dimethylformamide, butylcarbitol, Sodium diphosphate, sodium diphosphate, sodium diphosphate, phosphinic acid, oleylamine and polyol.

According to another embodiment, the metal salt reduction method comprises the steps of: (A) obtaining a dispersion containing the metal precursor, the organic amine, and the reducing agent; (B) applying the dispersion to the substrate and performing heat treatment in an inert gas atmosphere .

The coating method may be bar coating, slot die coating, spray coating, dip coating, blade coating, comma coating, squeeze coating, or the like.

(A2) adding an organic amine to the dispersion of step (A1); (A3) adding the organic amine to the dispersion of step (A2); and And adding the reducing agent to the dispersion.

According to another embodiment, the organic dispersion medium is selected from an alcohol dispersion medium, a glycol dispersion medium, or a mixed dispersion medium of the two.

Examples of the alcohol dispersion solvent include alcohols such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, Methyl-1-butanol, 2-methyl-1-butanol, 2-methyl-1-butanol, Propanol, 2-methyl-1-pentanol, 2-ethylbutanol, 2,4-dimethyl-3 -Hexanol, 2-heptanol, 2-ethyl-1-hexanol, 2,6-dimethyl-4-heptanol, 2-methylcyclohexanol , 3-methylcyclohexanol, 4-methylcyclohexanol, isopropyl alcohol, benzyl alcohol, cyclohexanol, and mixtures thereof.

Examples of the glycol dispersing agent include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, butylene glycol, hexylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene Ethylene glycol dimethyl ether, diethylene glycol methyl ether, diethylene glycol ethyl ether, diethylene glycol butyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether, But are not limited to, glycol monobutyl ether, triethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol dimethyl ether, dipropylene glycol methyl ether, and mixtures thereof.

According to another embodiment, the heat treatment is performed at 140 to 230 캜, preferably 160 to 220 캜.

If the heat treatment temperature is lower than 140 ° C, the organic materials and reaction by-products in the copper salt ink are not removed and the sheet resistance is increased. If the heat treatment temperature exceeds 230 ° C, the substrate is damaged at high temperature except for components such as para- not.

According to a most preferred embodiment of the present invention, the metal layer constituting (i) the conductive fiber aggregate should be formed by a metal salt reduction method using an organic amine and a reducing agent, and (ii) (Iii) the molar ratio of the organic amine and reducing agent used is from 1: 1 to 1: 1.7, (iv) the amount of the metal precursor , Organic amine and a reducing agent is applied to the substrate and the heat treatment temperature is in the range of 160 to 220 ° C in an inert gas atmosphere, and (v) the reducing agent used is formic acid.

If all of these process conditions are met, the metal layer must have a (1) average sphering rate of 0.1 to 0.7, (2) an average aspect ratio of 1.6 to 2.1, and (3) an average surface porosity of 3% to 6% And (4) all of the heat-treated organic amines which are required to be passed through the process of producing the conductive fiber aggregate are removed and are not retained in the conductive fiber aggregate.

If the above conditions (1) to (4) satisfy all of the above conditions, the sheet resistance of not more than 20 Ω / □, which is a desired effect of the present invention, (2) It was confirmed that the peelability that is not transferred to the tape at all can be achieved.

Another aspect of the present invention relates to a gasket comprising a conductive fiber assembly according to various embodiments of the present invention.

Another aspect of the present invention is directed to a conductive tape comprising a conductive fiber assembly according to various embodiments of the present invention.

Another aspect of the present invention relates to an electronic device comprising a conductive fiber assembly according to various embodiments of the present invention.

Hereinafter, the present invention will be described in more detail with reference to Examples and the like, but the scope and content of the present invention can not be construed to be limited or limited by the following Examples. It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the present invention as set forth in the following claims. It is natural that it belongs to the claims.

In addition, the experimental results presented below only show representative experimental results of the embodiments and the comparative examples, and the respective effects of various embodiments of the present invention which are not explicitly described below will be specifically described in the corresponding part.

Example

Example 1

To 4.8 g of copper acetate was added 5 mL of a dispersion medium composed of ethanol and ethylene glycol in a ratio of 1: 1, followed by stirring for 5 minutes. Octylamine was added dropwise at a rate of 1.5 times the molar amount of copper acetate for 4 minutes, and then formic acid was added thereto so as to have an F / A of 1.5, followed by stirring for 2 hours to prepare a copper precursor ink. In the present invention, F / A represents the molar ratio of formic acid to the input amine.

Example 2

Was prepared in the same manner as in Example 1 except that formic acid was added so as to have an F / A value of 1.4 to prepare a copper precursor ink.

Example 3

Was prepared in the same manner as in Example 1 except that formic acid was added so that F / A was 1.2 so as to prepare a copper precursor ink.

Comparative Example 1

The procedure of Example 1 was repeated except that pentylamine was added instead of octylamine and formic acid was added so that F / A was 1.7 so as to prepare a copper precursor ink.

Comparative Example 2

The procedure of Example 1 was repeated except that cyclohexylamine was added instead of octylamine, and formic acid was added so that F / A was 1.3, to prepare a copper precursor ink.

Comparative Example 3

Prepared in the same manner as in Example 1 except that cyclohexylamine was added instead of octylamine and a copper precursor ink was prepared without adding formic acid.

Comparative Example 4

The procedure of Example 1 was repeated except that cyclohexylamine was added instead of octylamine, and formic acid was added so that F / A was 3.4, thereby preparing a copper precursor ink.

Comparative Example 5

The procedure of Example 1 was repeated except that undecylamine was added instead of octylamine, and formic acid was added so that F / A was 1.2, to prepare a copper precursor ink.

Manufacturing example

Copper precursor inks prepared in Examples and Comparative Examples were applied to a fabric with a thickness of 100 mu m using a Bar coater. After a heat treatment in a nitrogen atmosphere and a temperature of 200 ° C for 10 minutes, the sheet was cooled gradually to room temperature to obtain a conductive fabric.

Experimental Example

The following properties were evaluated for the conductive fabric produced in the Production Example.

1. Surface resistance measurement

The sheet resistance was measured using a surface resistance meter (SR2000N).

2. Evaluation of peel resistance

1 ㅧ 2cm size and then attached to the conductive fabric manufacturing the adhesive tape for releasing by applying a force of 2kg _f. The tape was peeled off at a rate of 1 cm / second at an angle of 90 ^° to evaluate the degree of transfer of the metal layer to the tape. The degree of peeling resistance is classified by the ratio of the area transferred to the tape among the evaluated areas, 5 when no transfer is present, 4 when the transferred area is 5% or less, 3 when the area is 5 to 15%, 2 , 1 for 35 to 65%, and 0 for 65% or more.

3. Type analysis

The fabricated conductive fabric was analyzed by SEM to obtain an image, and then an average circularity, an aspect ratio, and an average surface porosity were calculated by the Image J program through the steps of FIGS. 2A to 2D as follows.

(Fig. 2A), the brightness and contrast are adjusted to clarify the image (Fig. 2B), the particle to be calculated is adjusted to a threshold value (2c), and each of the calculated particles The average sphericity, aspect ratio, and average surface porosity were calculated for image (2d).

While Examples 1 to 3 achieve the desired shape and physical properties of the present invention, Comparative Examples 1 to 4 do not achieve the desired shape and physical properties of the present invention, The alkylamine was not removed well after the heat treatment and the sheet resistance was high.

Claims (17)

(a) a fibrous aggregate, and (b) a metal layer formed on the surface of the fibrous aggregate,
The metal layer has a shape with an average spheroidization ratio of 0.1 to 0.7, an average aspect ratio of 1.6 to 2.1, and an average surface porosity of 3 to 6%
Wherein the conductive fiber aggregate has an organic amine residual amount of 0 to 300 ppm based on the total weight of the conductive fiber aggregate. The conductive fiber aggregate according to claim 1, wherein the metal layer is formed by a metal salt reduction method. The conductive fiber aggregate according to claim 2, wherein the metal salt reduction method is performed by reducing the metal salt precursor using an organic amine and a reducing agent. The conductive fiber aggregate according to claim 3, wherein the organic amine is at least one selected from the group consisting of a primary amine having 7 to 10 carbon atoms, a secondary amine having 3 to 6 carbon atoms, and a cyclic amine having 7 or 8 carbon atoms. The conductive fiber aggregate according to claim 4, wherein the organic amine and the reducing agent are used in a molar ratio of 1: 1 to 1: 2. The conductive fiber aggregate according to any one of claims 1 to 5, wherein the metal is at least one selected from the group consisting of copper, nickel, silver, aluminum, cobalt and alloys of two or more of these metals. The conductive fiber assembly according to any one of claims 1 to 5, wherein the substrate is selected from among fibers, fabrics, knitted fabrics and nonwoven fabrics. 6. The substrate according to any one of claims 1 to 5, wherein the substrate is selected from the group consisting of a polyester resin, a polyamide resin, a polyethylene resin, a polypropylene resin, a polyvinyl chloride resin, a polyvinyl resin, a polytetrafluoroethylene Based resin, a polyvinyl alcohol-based resin, a polyacrylonitrile-based resin, an aramid resin, an acrylic resin, and a polyurethane-based resin. The method of any one of claims 3 to 5, wherein the reducing agent is selected from the group consisting of formic acid, acrylic acid, phosphoric acid, citric acid, lactic acid, alanine, glycolic acid, glycine, acetic acid, formaldehyde, hydrazine, sodium borohydride, dimethylformamide, Wherein the conductive fiber aggregate is at least one selected from the group consisting of carbitol, glucose, tannic acid, sodium hypophosphite, phosphinic acid, oleylamine and polyol. The method of any one of claims 3 to 5, wherein the metal salt reduction method comprises the steps of (A) obtaining a dispersion containing the metal precursor, the organic amine, and the reducing agent, (B) applying the dispersion to the substrate And heat treatment in an inert gas atmosphere. (A2) adding an organic amine to the dispersion of step (A1); (A3) adding the organic amine to the dispersion of step (A2); and And adding the reducing agent to the dispersion and stirring the resulting mixture. 12. The conductive fiber aggregate according to claim 11, wherein the organic dispersion medium is selected from an alcohol dispersion medium, a glycol dispersion medium, and a mixed dispersion medium of the two. The conductive fiber aggregate according to claim 12, wherein the heat treatment is performed at 140 to 230 캜. The method of claim 13, wherein (i) the metal layer is formed by a metal salt reduction method using the organic amine and the reducing agent, (ii) the organic amine has 7 to 10 carbon atoms when the carbon number is the primary amine, (Iii) the molar ratio of the organic amine to the reducing agent is 1: 1 to 1: 1.7, (iv) the molar ratio of the metal precursor, the organic amine, the reducing agent Wherein the heat treatment temperature is in the range of 160 to 220 占 폚 in which the dispersion liquid is applied to the substrate and performed in an inert gas atmosphere, and (v) the reducing agent is formic acid. A gasket comprising a conductive fiber assembly according to any one of claims 1 to 5. A conductive tape comprising the conductive fiber assembly according to any one of claims 1 to 5. An electronic device comprising the conductive fiber aggregate according to any one of claims 1 to 5.

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