KR102051762B1 - Elastic paste composition - Google Patents

Abstract

Elastic paste composition includes nano carbon particles having 5 to 15% by weight and mixed with a carbon nanotube and a carbon nanoplate, 10 to 30% by weight of an amorphous co-polyester resin and extra solvent. Therefore, a thin film formed of the elastic paste composition may have excellent elasticity and electrical conductivity.

Description

Flexible Paste Composition {ELASTIC PASTE COMPOSITION}

The present invention relates to a flexible paste composition. More specifically, the present invention relates to a flexible paste composition that can be used as a heating element while being stretchable on a flexible substrate.

The planar heating element forms a planar heating layer on the substrate. At this time, when power is applied to the planar heating layer, a heat generation phenomenon occurs according to the sheet resistance of the planar fuming layer. The surface heating layer may form a conductive paste through a printing process.

Currently, the planar heating element commercially available forms a planar heating layer on a hard and unstretched substrate like the ceramic. That is, when the substrate is bent or stretched, there is a problem that a crack occurs in the planar heating layer or peels from the substrate.

There is a study on a flexible paste composition for forming a planar heating layer through a printing process on a flexible, stretchable garment fabric, and a heat-resistant urethane film. When the reliability, sheet resistance, etc. of the stretchable paste composition are secured, the stretchable paste composition may be used as an electrode and a heat dissipation layer in a heating fabric, a biosensor, a wearable device, and a flexible device.

One object of the present invention is to provide a flexible paste composition having excellent elongation and sheet resistivity.

Stretch paste composition according to an embodiment of the present invention, 5 to 15% by weight, carbon nanotubes and carbon nanoplates are mixed nano carbon particles, 10 to 30% by weight of the amorphous copolyester (amorphous co-polyester ) Resins and excess solvent.

In one embodiment of the present invention, the copolyester resin may be a mixture of the first copolyester resin group and the second copolyester resin group having a different transition temperature and hydroxyl value.

Here, the difference in the transition temperature may have a range of 10 to 20 ° C. On the other hand, the difference between the hydroxyl value may have a range of 1-2 KOH mg / g.

In one embodiment of the present invention, the copolyester resin is a first copolyester resin having a different transition temperature in the range of 10 to 20 ° C and different hydroxyl groups in the range of 1-2 KOH mg / g The group and the second copolyester resin group can be mixed.

In one embodiment of the present invention, the carbon nanotubes may be mixed with the first carbon nanotube group and the second carbon nanotube group having different tube lengths and average diameters.

Here, the difference in the tube length may have a range of 100 to 150 μm. On the other hand, the difference in the average diameter may have a range of 2 to 10 mm.

In one embodiment of the invention, the carbon nanotubes comprise mixing groups of carbon nanotubes having different tube lengths ranging from 100 to 150 μm and different average diameter differences ranging from 2 to 10 mm. can do.

In one embodiment of the present invention, the carbon nanoplate may include a mixture of the first carbon nanoplate group and the second carbon nanoplate group having different thicknesses and surface areas.

Here, the difference in thickness may have a range of 5 to 100 nm. On the other hand, the difference in the surface area may have a range of 10 to 100 m ² / g.

In one embodiment of the present invention, the carbon nanoplate is a group and the first carbon nanoplate group having a different thickness in the range of 5 to 100 nm and different surface area in the range of 10 to 100 m ² / g It may contain a mixture of two carbon nanoplate group.

According to the embodiments of the present invention, the stretchable paste composition may include nano carbon particles in which carbon nanotubes and carbon nanoplates are mixed, thereby ensuring stretch and electrical conductivity at the same time.

Furthermore, as each of the carbon nanotubes and the carbon nanoplates is made of a mixture of different groups, the flexible paste composition may have more excellent properties.

Hereinafter, the present invention will be described in more detail through embodiments of the present invention. However, the present invention should not be construed as limited to the embodiments described below and may be embodied in various other forms. The following examples are provided to fully convey the scope of the invention to those skilled in the art, rather than to allow the invention to be fully completed.

When an element is described as being disposed or connected on another element or layer, the element may be placed or connected directly on the other element, and other elements or layers may be placed therebetween. It may be. Alternatively, where one element is described as being directly disposed or connected on another element, there may be no other element between them. Terms such as first, second, third, etc. may be used to describe various items such as various elements, compositions, regions, layers and / or parts, but the items are not limited by these terms. Will not.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Also, unless otherwise defined, all terms including technical and scientific terms have the same meaning as would be understood by one of ordinary skill in the art having ordinary skill in the art. Such terms, such as those defined in conventional dictionaries, will be construed as having meanings consistent with their meanings in the context of the related art and description of the invention, and ideally or excessively intuitional unless otherwise specified. It will not be interpreted.

Embodiments of the invention are described with reference to cross-sectional illustrations that are schematic illustrations of ideal embodiments of the invention. Accordingly, changes from the shapes of the illustrations, such as changes in manufacturing methods and / or tolerances, are those that can be expected. Accordingly, embodiments of the invention are not intended to be limited to the particular shapes of the areas described as the illustrations, but include deviations in the shapes, the areas described in the figures being entirely schematic and their shapes It is not intended to describe the precise shape of the region nor is it intended to limit the scope of the invention.

Hereinafter, preferred embodiments of the present invention will be described in detail.

Flexible paste composition

Stretch paste composition according to embodiments of the present invention, 5 to 15% by weight of the nano carbon particles and carbon nanotubes and carbon nanoplates mixed, 10 to 30% by weight of the amorphous co-polyester (amorphous co-polyester) resin And excess solvents.

The nano carbon particles may include, for example, carbon nato tubes or carbon nano plates. The nano carbon particles may be used as the heat generating layer of the planar heating element as it has excellent sheet resistance along with conductivity.

The nano carbon particles are mixed at a ratio of 5 to 15% by weight. When the nano-carbon particles are less than 5% by weight, the electrical conductivity of the stretchable paste composition is deteriorated, making it difficult to use the heat generating layer. On the other hand, when the nano carbon particles are more than 15 wt%, the wettability of the nano carbon particles may deteriorate. Therefore, it is difficult for the stretchable paste to be uniformly dispersed in the stretchable paste composition.

In one embodiment of the present invention, the carbon nanotubes may be mixed with the first carbon nanotube group and the second carbon nanotube group each having a different tube length and each different average diameter.

 The difference in tube length can range from 100 to 150 μm. The mean diameter difference can range from 2 to 10 mm.

When the carbon nanotubes form a conductive thin film using the flexible paste composition made of the carbon nanotubes according to the tube length and the average diameter, the stretching rate and the resistance change rate of the conductive thin film may vary. This is because the length and average diameter of the carbon nanotubes have a great influence on the conductive path of the conductive thin film including the carbon nanotubes. Therefore, when the conductive thin film is formed using the flexible paste composition in which the first carbon nanotube group and the second carbon nanotube group are mixed, excellent stretch ratio and resistance change rate can be secured.

The carbon nanotubes may be any kind of carbon nanotubes such as single-walled carbon nanotubes, double-walled carbon nanotubes, multi-walled carbon nanotubes, bundle type carbon nanotubes, and these may be used alone or in combination of two or more thereof. For example, in economic terms, multi-walled carbon nanotubes can be used.

In one embodiment of the present invention, the carbon nanoplate may be a mixture of the first carbon nanoplate group and the second carbon nanoplate group having a different thickness and surface area. Here, the difference in thickness may have a range of 5 to 100 nm. On the other hand, the difference in the surface area may have a range of 10 to 100 m ² / g.

According to the carbon nanoplate, when the conductive thin film is formed using the stretchable paste composition made of the carbon nanotubes according to the thickness and the surface area of the particles, the stretch rate and the resistance change rate of the conductive thin film may vary. This is because the thickness and surface area of the carbon nanoplate have a great influence on the conductive path of the conductive thin film including the carbon nanoplate. Therefore, when the conductive thin film is formed using the flexible paste composition in which the first carbon nanoplate group and the second carbon nanoplate group are mixed, excellent stretch ratio and resistance change rate can be secured.

The amorphous copolyester resin corresponds to a resin that can be dissolved in the solvent. The amorphous copolyester may impart excellent adhesion to substrates such as polyester fibers and binding between the nano carbon particles. In particular, the amorphous copolyester may have excellent solubility compared to crystalline copolyester having insolubility.

The amorphous copolyester (amorphous co-polyester) resin may be included in the range of 10 to 30% by weight. In the above range, the paste composition may have uniform dispersibility and excellent applicability, and maintain binding force to the substrate.

In one embodiment of the present invention, the copolyester resin may be mixed with the first copolyester resin group and the second copolyester resin group having a different transition temperature and hydroxyl group value. Here, the difference in the transition temperature may have a range of 10 to 20 ° C. In addition, the difference between the hydroxyl value may have a range of 1-2 KOH mg / g.

In other words, the transition temperature and the hydroxyl value differ between the first and second copolyester resin groups depending on the bonding structure. In addition, the average molecular weight and the curing characteristics differ between the first and second copolyester resin groups.

Therefore, when the transition temperature and the hydroxyl value are high, the thin film formed of the flexible paste composition may have excellent hardness and elasticity, while relatively softness and adhesion of the thin film may be insufficient. On the other hand, when the transition temperature and the hydroxyl value are low, the ductility and adhesion of the thin film may be excellent.

Therefore, when the first copolyester resin group and the second copolyester resin group having different transition temperatures and hydroxyl groups are mixed, the hardness, elasticity, ductility, and adhesive strength of the thin film are complemented to each other so that the thin film has excellent mechanical properties. It may have characteristics and electrical properties.

The solvent may dilute the amorphous copolyester resin. In addition, the solvent may be used as a diluent of the flexible paste composition.

The solvent is alpha-terpineol, -N-methylpyrrolidone, N-methylpyrrolidone, butyl cellosolve, butyl cellosolve acetate, ethyl cellosolve ), Ethyl cellosolve acetate, ethyl carbitol, ethyl carbitol acetate, butyl carbitol, butyl carbitol acetate, ethoxy ethyl Ethoxyethyl acetate, butyl acetate, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, gamma-butyrolactone, Methyl ethyl ketone or combinations thereof.

Additives may be additionally included in the flexible paste composition to ensure the desired physical properties. Various commonly used additives include surfactants, surfactants, wetting dispersants, antioxidants, thixotropic agents, reinforcing fibers, silane functional perfluoroethers, phosphate functional perfluoroethers, titanates, waxes, phenol formaldehydes. , Air release agents, flow additives, adhesion promoters, rheology modifiers and spacer beads. The additional ingredients are optional and specifically selected to obtain any physical properties desirable for the selected end use. When used, the additives may comprise up to about 10 weight percent of the total dry composition.

Process for preparing stretch paste composition

First, a binder is prepared through a first mixing process in which an amorphous copolyester and a solvent are heated. After cooling the binder, an additive (wet dispersant) is mixed to prepare a vehicle having a low viscosity.

Subsequently, the nano carbon particles are kneaded while the solvent is additionally supplied to the vehicle to form a first dispersed mixture. The kneading process for the first dispersion may be performed using a planetary mixer.

Thereafter, the first dispersed mixture is secondarily dispersed through a roll-milling process to prepare a flexible paste composition. The kneading process for the secondary dispersion is achieved by applying pressure and shear force to the mixture by using a three-roll-milling equipment using three rolls of rotation and a difference in rotational speed between the rollers and a micro gap between the rollers. Kneading of the mixture can be carried out.

Embodiment of Flexible Paste Composition_Heating Element

According to one embodiment of the present invention, a heating element including a sintered product of the stretchable paste composition is provided.

The heating element may be manufactured by, for example, a manufacturing method including the step of sintering the above-described stretchable paste composition at a temperature in the range of 400 ° C to 1200 ° C.

The planar heating element according to an embodiment includes the heating element. The heating element is, for example, applying a flexible paste composition described above on a substrate; And it may be prepared by a manufacturing method comprising the step of sintering the paste composition at a temperature range of 400 ℃ to 1200 ℃. The substrate may correspond to a fiber as a support for supporting the planar heating element.

The flexible paste composition may be formed using various methods such as screen printing, ink jet, dip coating, spin coating, or spray coating. Can be applied onto.

When applying the stretchable paste composition, the coating amount of the paste composition may be adjusted so that the organic vehicle may be evaporated by the subsequent firing and the heating element finally obtained may have a predetermined thickness, and may be repeatedly applied for this purpose.

Next, the applied stretchable paste composition may be sintered at, for example, 400 ° C. to 1,200 ° C. to obtain a planar heating element on the substrate. Through the sintering, the organic vehicle contained in the flexible paste composition evaporates. The sintering temperature may be selected in consideration of the material of the substrate and the coating thickness of the composition.

Hereinafter, the present invention will be described in more detail with reference to specific embodiments.

1. Preparation of Amorphous Copolyester

An amorphous copolyester was prepared as shown in Table 1 below.

division Molecular Weight
(Mn) importance
(at 30 ℃) Transition temperature Tg (℃) Hydroxyl value
(KOHmg / g) Acid
(KOHmg / g) Toyoko
Vylon 630
(Resin 1) 23,000 1.20 7 5 <2 Vylon 550
(Resin 2) 28,000 1.17 -15 4 <2 Vylon UR 6100 (Resin 3) 25,000 - -30 4 ~ 6 <1

2. Preparation of Carbon Nanotubes

Carbon nanotubes were prepared as shown in Table 2 below.

division Bulk density
(g / cc) Surface area
(m ² / g) Length
(um) diameter
(nm) Korea, CNT
Ctube 199
(CNT 1) 0.06 to 0.1 400 to 700 100 to 200 8 Ctube 170
(CNT 2) 0.3 to 0.4 200 to 700 50 to 200 10 Ctube 120
(CNT 3) 0.4 to 0.6 200 to 250 20 to 100 20

3. Preparation of Carbon Nanoplates

Carbon nanotubes were prepared as shown in Table 3 below.

division Bulk Density (g / cc) Oxygen content Residue
Amount importance
(g / cc) thickness
(nm) Surface area
(m ² / g) diameter
(um) XG Science, USA
Grade c
(CNP 1) 0.2 to 0.4 <1% - 2.0 to 2.25 Submicron 300,500,750 2 um Grade m
(CNP 2) 0.03 to 0.1 <1% <0.5 wt% 2.0 to 2.25 15 50 to 80 5,15,25 Grade h
(CNP 3) 0.03 to 0.1 <1% <0.5 wt% 2.0 to 2.25 6 to 8 120 to 150 5,15,25 Grade r
(CNP 4) 0.03 to 0.1 <5% <0.5 wt% 2.0 to 2.25 - 30 to 60 7,10,25

4. Preparation of Solvent

As a solvent, butyl cellosolve manufactured by Yulsan Co., Ltd. was prepared.

A binder was prepared in the composition ratio of Table 4 below by first mixing the amorphous copolyester and the solvent in a heated state. Elasticity test for the binder 1 to 10 was performed.

bookbinder
Kinds Resin 1
(w%) Resin 2
(w%) Resin 3
(w%) menstruum
(w%) Elasticity Test Results Binder 1 30 0 0 70 △ Binder 2 20 10 70 ○ Binder 3 20 0 10 70 ○ Binder 4 0 30 0 70 Χ Binder 5 10 20 0 70 ○ Binder 6 0 20 10 70 Χ Binder 7 0 0 30 70 Χ Binder 8 0 10 20 70 △ Binder 9 10 10 10 70 ○ Binder 10 20 5 5 70 ◎

◎; Very good, ○: Good, △: Normal, C: Poor

 As a result of the above-mentioned elasticity test, it was confirmed that binder 10, that is, a binder including 20 w% Resin 1, 5 w% Resin 2, 5 w% Resin 3, and 70w% solvent had the best elasticity.

Then, a vehicle was prepared by mixing 10 wt% of a binder and 10 wt% of an additive (wet dispersant; DISPERBYK-110 manufactured by BYK).

Thereafter, an elastic paste composition was prepared while controlling the mixing ratio of the nano carbon particles to the vehicle. At this time, the optimum mixing ratio of the nano carbon particles was secured by using the sheet resistance value. In contrast, the mixing ratio of the nano carbon particles is described in Table 5 below.

Separator paste CNT 1 (wt%) Binder 10
(wt%) menstruum
(wt%) Wet Dispersant
(wt%) Sheet resistance
(Ω / □) Paste 1 10 30 50 10 500 2 15 30 45 10 100 3 20 30 40 10 50 4 25 30 35 10 45 5 30 30 30 10 40

As confirmed in Table 5 above, it can be seen that the paste in which the carbon nanotubes are mixed at 20 to 30 w% has excellent sheet resistance characteristics. On the other hand, when the carbon nanotubes are 15 w% and 10 w%, the sheet resistance is too high, it can be seen that the electrical resistance is not expressed.

On the other hand, the carbon nanotubes and carbon nanoplates are used alone or mixed to adjust the mixing ratio within the carbon nano powder 20 to 30% by weight, while adjusting the ratio of the solvent accordingly to prepare a flexible paste composition. Detailed mixing ratios thereof are shown in Table 6 below.

Paste separator
CNT
(w%) CNP
(w%) Binder 10
(w%) menstruum
(w%) Wet Dispersant
(w%) Example 1 5 15 30 40 10 Example 2 5 20 30 35 10 Example 3 5 25 30 30 10 Example 4 10 10 30 40 10 Example 5 10 15 30 35 10 Example 6 10 20 30 30 10 Example 7 15 5 30 40 10 Example 8 15 10 30 35 10 Example 9 15 15 30 30 10 Comparative Example 1 20 0 30 40 10 Comparative Example 2 0 20 30 40 10

Sheet resistance and specific resistance of the above-described mixed paste composition related Examples 1 to 9 were measured. This is described in Table 7.

In order to measure the sheet resistance and non-constant, a thin film in a sheet form is formed on the substrate through a screen printing process. Thereafter, the drying process was performed for 15 minutes at a temperature of 150 ° C. The sheet resistance of the thin film was measured with a 4 probe measuring instrument. Then, the specific resistance value was calculated using the measured sheet resistance value and the thickness of the thin film. Hereinafter, the sheet resistance and non-constant value for Examples 1 to 9 and Comparative Examples 1 and 2 are shown in Table 7.

Paste Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Comparative Example 1 Comparative Example 2 Sheet resistance
(Ω / □) 55 47 56 30 35 36 55 50 51 78 86 Resistivity
(1x10 ^-2 Ω ?? cm) 5.5 4.7 5.8 3.0 3.5 3.8 5.5 5.0 5.1 7.8 8.6

As described above, when using carbon nanotubes or carbon nanoplates alone (Comparative Examples 1 and 2), the thin film using the flexible paste composition in which the carbon nanotubes and the carbon nanoplates are mixed has excellent electrical properties. can confirm.

Although embodiments of the present invention have been described above, these are merely exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom.

Claims (13)

Nano carbon particles having 5 to 15 wt% and mixed with carbon nanotubes and carbon nanoplates;
10-30% by weight of an amorphous copolyester resin; And
Contains excess solvent,
The carbon nanotube: The carbon paste is stretchable composition, characterized in that the carbon nano plate is mixed in a weight ratio of 1: 1/3 to 5. The stretchable paste composition of claim 1, wherein the copolyester resin is a mixture of a first copolyester resin group and a second copolyester resin group having different transition temperatures and hydroxyl values. According to claim 2, wherein the difference in the transition temperature stretch paste composition, characterized in that it has a range of 10 to 20 ° C. The stretchable paste composition of claim 2, wherein the hydroxyl value is in the range of 1-2 KOH mg / g. The method of claim 1, wherein the copolyester resin has a first nose having different transition temperature in the range of 10 to 20 ° C and different hydroxyl value in the range of 1-2 KOH mg / g. A stretch paste composition comprising a polyester resin group and a second copolyester resin group. The stretch paste composition of claim 1, wherein the carbon nanotubes are a mixture of a first carbon nanotube group and a second carbon nanotube group having different tube lengths and average diameters. 7. The flexible paste composition of claim 6, wherein the difference in tube length ranges from 100 to 150 μm. The stretchable paste composition of claim 6, wherein the difference in average diameter is in the range of 2 to 10 mm. The method of claim 1, wherein the carbon nanotubes are stretchable, characterized in that a mixture of carbon nanotube groups having different tube lengths in the range of 100 to 150 μm and different average diameters in the range of 2 to 10 mm Paste composition. The stretchable paste composition of claim 1, wherein the carbon nanoplate is a mixture of a first carbon nanoplate group and a second carbon nanoplatelet group having different thicknesses and surface areas. 11. The flexible paste composition of claim 10, wherein the thickness difference is in the range of 5 to 100 nm. 11. The flexible paste composition of claim 10, wherein the difference in surface area ranges from 10 to 100 m ² / g. The first and second carbon nanoplate groups of claim 1, wherein the carbon nanoplates have different thicknesses in the range of 5 to 100 nm and different surface areas in the range of 10 to 100 m ² / g. An elastic paste composition characterized by mixing a plate group.