KR101524642B1 - Heating paste composition for forming thick film and portable low power heater using the same - Google Patents

Abstract

Disclosed are a heating paste composition for forming a thick film and a portable low power heater using the same. The heating paste composition for forming the thick film according to one embodiment of the present invention includes 3 to 6wt% of carbon nanotube particles, 0.5 to 30wt% of carbon nanoparticles, 10 to 30wt% of mixed binders, 29 to 83wt% of organic solvents, and 0.5 to 5wt% of dispersants with regard to 100wt% of the heating paste composition. The mixed binder is made by mixing epoxy acrylate or hexamethylene diisocyanate, polyvinyl acetal, and phenol resin.

Description

TECHNICAL FIELD [0001] The present invention relates to an exothermic paste composition for forming a thick film and a portable low-power heat-generating heater using the same. BACKGROUND ART [0002]

The present invention relates to an exothermic paste composition and a portable heat-generating heater using the same, and more particularly, to a heat-generating paste composition for forming a thick film and a portable low-power heat-generating heater using the same.

Unlike linear heating elements, plane heating elements generate uniform heat on the surface, so they are 20 ~ 40% more energy efficient than linear heating elements, and are relatively safe because they do not emit electromagnetic waves during DC driving. A metal heating element such as iron, nickel, chromium, or platinum, which has high thermal conductivity, is uniformly sprayed or printed on a film-shaped resin or the like, or an electrically conductive inorganic particle heating element such as carbon, graphite, Mixed. In recent years, many carbon-based surface heating elements having strong heat and durability, good thermal conductivity, low thermal expansion coefficient and light characteristics have been studied.

The surface heating element using a carbonaceous material is made of a paste formed by mixing a conductive carbonaceous powder such as carbon, graphite, carbon black or carbon nanotube with a binder, and the amount of the conductive material and the binder used is Accordingly, conductivity, workability, adhesion, scratch resistance and the like are determined.

However, in the case of the exothermic paste based on the conventional carbon nanotubes, it has been difficult to have high heat resistance. In particular, the exothermic paste having a high heat resistance at a temperature of about 200 ° C. to 300 ° C. while being capable of screen printing, gravure printing, There is no report. In addition, in the case of designing to have high heat resistance, the drying temperature (curing temperature) is close to 300 DEG C, and it is pointed out that it is difficult to apply it to a flexible substrate made of a plastic material.

On the other hand, the conventional carbonaceous heating paste has a relatively high resistivity and is difficult to form a thick film, which makes it difficult to drive the heater using the low-voltage / low-power heater.

Patent Document 1: Korean Patent No. 10-1294596 (Announcement 2013.08.09)

Embodiments of the present invention provide an exothermic paste composition for forming a thick film capable of being driven at a low voltage and a low electric power by having a small resistance change due to high temperature resistance and low specific resistance, and a portable low power heat heater using the same.

According to one aspect of the present invention, there is provided a heat generating paste composition comprising 3 to 6 parts by weight of carbon nanotube particles, 0.5 to 30 parts by weight of carbon nanoparticles, 10 to 30 parts by weight of a mixed binder, 29 to 83 parts by weight of an organic solvent, And 0.5 to 5 parts by weight of a dispersant, wherein the mixed binder may be an exothermic paste composition for forming a thick film in which epoxy acrylate or hexamethylene diisocyanate, polyvinyl acetal, and phenolic resin are mixed.

At this time, the mixed binder may be mixed with 10 to 150 parts by weight of a polyvinyl acetal resin and 100 to 500 parts by weight of a phenolic resin, based on 100 parts by weight of epoxy acrylate or hexamethylene diisocyanate.

In addition, 0.5 to 5 parts by weight of a silane coupling agent may be further added to 100 parts by weight of the exothermic paste composition.

In addition, the carbon nanotube particles may be multi-walled carbon nanotube particles.

The organic solvent may be selected from the group consisting of carbitol acetate, butyl carbitol acetate, DBE (dibasic ester), ethyl carbitol, ethyl carbitol acetate, dipropylene glycol methyl ether, cellosolve acetate, butyl cellosolve acetate, Or a combination thereof.

According to another aspect of the present invention, there can be provided a surface heating element formed by screen printing, gravure printing, or comma coating on a substrate with an exothermic paste composition according to one aspect of the present invention.

At this time, the substrate may be a polyimide substrate, a glass fiber mat, or a ceramic glass.

The organic EL device may further include a protective layer formed of an organic material having a black pigment such as silica or carbon black coated on the upper surface of the planar heating element.

The exothermic paste composition for forming a thick film according to the embodiments of the present invention can maintain the heat resistance even at a temperature of 200 ° C or higher, so that the resistance change with temperature is small and stable.

In addition, since the exothermic paste composition has a low resistivity and is easy to control its thickness, it can be heated at a low voltage and at a low power, so that a heater with higher efficiency can be manufactured.

Further, since it can be thermally cured at about 100 ° C to 150 ° C, it can be applied to various flexible substrates.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an image of a surface heating element specimen produced using an exothermic paste composition according to the present invention. FIG.
FIG. 2 is an image of the heat stability test of the surface heating element samples prepared according to the examples and the comparative examples.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The exothermic paste composition for forming a thick film (hereinafter, exothermic paste composition) according to an embodiment of the present invention includes carbon nanotube particles, carbon nanoparticles, a mixed binder, an organic solvent, and a dispersant.

Specifically, 3 to 6 parts by weight of carbon nanotube particles, 0.5 to 30 parts by weight of carbon nanoparticles, 10 to 30 parts by weight of a mixed binder, 29 to 83 parts by weight of an organic solvent, 0.5 to 5 parts by weight of a dispersing agent .

The carbon nanotube particles may be selected from single-walled carbon nanotubes, double-walled carbon nanotubes, multi-walled carbon nanotubes, or a mixture thereof. For example, the carbon nanotube particles may be multi wall carbon nanotubes. When the carbon nanotube particles are multi-walled carbon nanotubes, the diameter may be 5 nm to 30 nm and the length may be 3 to 40 μm.

The carbon nanoparticles may be, for example, graphite nanoparticles, and may have a diameter of 1 to 25 mu m.

The mixed binder functions to allow the exothermic paste composition to have heat resistance even in a temperature range of about 300 DEG C, and can be formed of epoxy acrylate or hexamethylene diisocyanate, polyvinyl acetal, Phenol resin (Phenol resin) mixed form. For example, the mixed binder may be a mixture of an epoxy acrylate, a polyvinyl acetal, and a phenolic resin, or a mixture of hexamethylene diisocyanate, a polyvinyl acetal, and a phenolic resin. In the present invention, by increasing the heat resistance of the mixed binder, even when it is heated at a high temperature of about 300 캜, it has an advantage that there is no change in the resistance of the material or breakage of the coating film.

Herein, the phenolic resin means a phenolic compound including a phenolic resin and a phenolic resin. For example, the phenol derivatives may be selected from the group consisting of p-cresol, o-Guaiacol, Creosol, Catechol, 3-methoxy-1,2- Homoxatechol, Vinylguaiacol, Syringol, Iso-eugenol, Methoxyeugenol, o (methyloxy) benzene, -Cresol, 3-methyl-1,2-benzenediol, (z) -2-methoxy-4- (1-propenyl) -phenol (z) -2-methoxy-4- (1-propenyl) -phenol, 2,6-dimethoxy-4- (2-propenyl) Phenol, 3,4-dimethoxy-phenol, 4-ethyl-1,3-benzenediol, resole phenol, , 4-methyl-1,2-benzenediol, 1,2,4-benzene triol, 2-methoxy-6-methyl 2-methoxy-6-methylphenol, 2-methoxy-4-vinylphenol or 4-ethyl-2-methoxy-phenol ), And the like Information that is not.

The mixing ratio of the mixed binder may be 10 to 150 parts by weight of polyvinyl acetal resin and 100 to 500 parts by weight of phenol resin based on 100 parts by weight of epoxy acrylate or hexamethylene diisocyanate. When the content of the phenolic resin is less than 100 parts by weight, heat resistance of the heat generating paste composition is deteriorated. When the content of the phenolic resin is more than 500 parts by weight, the flexibility is lowered.

The organic solvent is used for dispersing the conductive particles and the binder. The organic solvent is selected from the group consisting of Carbitol acetate, Butyl carbotol acetate, DBE (dibasic ester), Ethyl Carbitol, Ethyl Carbitol Acetate, Glycol methyl ether, cellosolve acetate, butyl cellosolve acetate, butanol, and octanol.

Meanwhile, various methods commonly used may be applied to the dispersion process. For example, ultrasonic treatment (roll-milling), bead milling or ball milling Lt; / RTI >

Dispersing agents are used to make the dispersion more smooth. Common dispersants used in the art such as BYK, amphoteric surfactants such as Triton X-100, and ionic surfactants such as SDS can be used.

The exothermic paste composition according to an embodiment of the present invention may further include 0.5 to 5 parts by weight of a silane coupling agent per 100 parts by weight of the exothermic paste composition.

The silane coupling agent functions as an adhesion promoter for enhancing the adhesive force between the resins when the exothermic paste composition is blended. The silane coupling agent may be an epoxy-containing silane or a mercaptan-containing silane. Examples of such silane coupling agents include epoxy-containing 2- (3,4-epoxycyclohexyl) -ethyltrimethoxysilane, 3-glycidoxytrimethoxysilane, 3-glycidoxypropyltriethoxysilane, (Aminoethyl) 3-aminopropylmethyldimethoxysilane, N-2 (aminoethyl) 3-aminopropyltrimethoxysilane having an amine group and N-2 , N-2 (aminoethyl) 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl- Propylamine, N-phenyl-3-aminopropyltrimethoxysilane, and 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltriethoxysilane, isocyanate, And 3-isocyanate propyltriethoxysilane, etc., and are limited to those listed above No.

The present invention further provides an exothermic paste composition formed by screen printing, gravure printing (or roll-to-roll gravure printing) or comma coating (or roll-to-roll comma coating) on a substrate according to the above-described embodiments of the present invention do.

Wherein the substrate is selected from the group consisting of polycarbonate, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyimide, cellulose ester, nylon, polypropylene, polyacrylonitrile, polysulfone, polyester sulfone, polyvinylidene fluoride , Glass, glass fiber (mat), ceramic, SUS, copper or aluminum substrate, and the like. The substrate can be appropriately selected depending on the application field of the heating element and the use temperature.

The surface heating element may be formed by printing an exothermic paste composition according to embodiments of the present invention on the substrate in a desired pattern through screen printing or gravure printing, drying and curing the paste, or printing and drying / Followed by curing to form an electrode. Or by printing or drying / curing a silver paste or a conductive paste, and then screen printing or gravure printing the heating paste composition according to the embodiments of the present invention on the top.

The planar heating element may further include a protective layer coated on the upper surface. The protective layer may be formed of silica (SiO ₂ ). When the protective layer is formed of silica, it has an advantage that flexibility of the heating element can be maintained even if it is coated on the heating surface.

Hereinafter, an exothermic paste composition for forming a thick film according to the present invention and a planar heating element using the same will be described in detail with reference to test examples. The following test examples are only illustrative of the present invention, and the present invention is not limited by the following test examples.

Test Example

(1) Preparation of Examples and Comparative Examples

Examples (3 kinds) and comparative examples (3 kinds) were prepared as shown in Table 1 below. It is to be noted that the composition ratios indicated in [Table 1] are expressed as% by weight.

Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 CNT particles 4 5 6 4 5 6 CNP particles 8 9 15 - - - Mixed binder 20 15 22 - - - Ethyl cellulose - - - 10 12 14 Organic solvent 63 67 52 82 79 76 Dispersant (BYK) 5 4 5 4 4 4

In the examples, CNT particles and CNP particles (Examples 1 to 3) were added to a carbitol acetate solvent according to the composition of [Table 1], BYK dispersant was added, and dispersion A was prepared through ultrasonic treatment for 60 minutes Respectively. Thereafter, the master batch was prepared by adding the mixed binder to the carbitol acetate solvent and then mechanically stirring. Next, the dispersion A and the masterbatch were firstly kneaded by mechanical stirring and then subjected to a second-order kneading by a three-roll-milling process to prepare an exothermic paste composition.

In the comparative examples, the CNT particles were added to the carbitol acetate solvent according to the composition of [Table 1], BYK dispersant was added, and the dispersion was prepared by ultrasonication for 60 minutes. After that, ethyl cellulose was added to the carbitol acetate solvent and the master batch was prepared by mechanical stirring. Next, the dispersion B and the masterbatch were firstly kneaded through mechanical stirring, and then subjected to a second-order kneading through a three-roll-mill process to prepare an exothermic paste composition.

(2) Evaluation of surface heating element characteristics

After heating paste compositions according to Examples and Comparative Examples were screen printed on a polyimide substrate with a size of 10 x 10 cm and cured, a silver paste electrode was printed on both ends and cured to prepare a surface heating element sample.

1 is an image of a surface heating element specimen produced using an exothermic paste composition according to the present invention. 1A is a planar heating element formed by screen printing an exothermic paste composition on a polyimide substrate. 1B is a planar heating element formed by screen printing a heating paste composition on a glass fiber mat. 1C and 1D are images obtained by coating a protective layer on top of the planar heating element of FIG. 1A (FIG. 1C is a black protective layer coating and FIG. 1D is a green protective layer coating).

The specific resistance of the surface heating element sample (example) as shown in Fig. 1A and the surface heating element samples prepared according to the above comparative example were measured (voltage / current applied is shown in Table 2). Further, in order to confirm the effect of the temperature increase according to the applied voltage / current, the surface heating elements corresponding to the examples and the comparative examples were heated to 40, 100 and 200 ° C, respectively. The current was measured.

In addition, the heat stability at 200 캜 was tested for each sample. In FIG. 2, images of heat stability tests of the surface heating element samples prepared according to Examples and Comparative Examples are shown, and the test results are summarized in Table 2 below.

Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Resistivity (× 10 ^-2 Ωcm) 1.9 2.55 2.96 9.73 8.52 6.23 40 ℃ reaching DC drive voltage / current 5V / 0.2A 6V / 0.2A 7V / 0.2A 20V / 0.3A 16V / 0.2A 12V / 0.2A 100 ℃ reach DC drive voltage / current 9V / 0.5A 12V / 0.4A 14V / 0.5A 48V / 0.7A 40V / 0.7A 26V / 0.6A 200 ℃ reaching DC drive voltage / current 20V / 0.6A 24V / 0.7A 24V / 1.0A - - - Heat stability (day) More than 20 days More than 20 days More than 20 days Bad Bad Bad

Referring to Table 2, the specific resistance of the planar heating elements corresponding to the embodiments were measured to be smaller than those of the planar heating elements corresponding to the comparative examples. Accordingly, the driving voltage / Was smaller than that of the planar heating elements corresponding to the comparative examples. That is, it can be confirmed that the planar heating elements corresponding to the embodiments can be driven with lower voltage and lower power than the comparative example.

Further, in the planar heating elements according to Examples 1 to 3, stability was maintained for 20 days under exothermic driving at 200 ° C (no separate protective layer), whereas in Comparative Examples 1 to 3, A defective phenomenon that the surface of the heat generating portion swells up within a predetermined time was observed. That is, it can be confirmed that the surface heating elements corresponding to the embodiments can be stably driven at a temperature higher than 200 ° C. than the comparative example.

The present invention further provides a portable heating heater including the above-described surface heat emission element and a power supply section for supplying electric power to the surface heat emission element.

Here, the power supply unit may include a lead electrode coated on left and right sides of the surface heating element, and a power supply connection electrode formed on the lead electrode. In some cases, the power connection electrode may be directly connected to the planar heating element. The lead electrode or the power connection electrode can be formed using silver paste, copper paste, copper tape, or the like.

The portable heating heater according to the present invention has a form in which the planar heating element is attached, embedded or mounted on the inside or the outside of the body, and includes a power supply for driving the planar heating element. Such a portable heating heater can be used for an inner sheet for a baby carriage, a heating sock, a heating foot, a heating cap, a portable heating mat, a portable cooking utensil, a heating sheet for a car, and the like.

Particularly, since the planar heating element used in the portable heating heater according to the present invention can be driven with low voltage and low power as described above, it can be driven by a secondary battery capable of charging / discharging such as a lithium ion battery and a lithium polymer battery, The portability is improved and the use time can be greatly increased.

The embodiments of the present invention have been described above. 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 or scope of the inventive concept as defined by the appended claims. It will be understood that various modifications may be made without departing from the scope of the present invention.

Claims (9)

3 to 6 parts by weight of carbon nanotube particles, 0.5 to 30 parts by weight of carbon nanoparticles, 10 to 30 parts by weight of a mixed binder, 29 to 83 parts by weight of an organic solvent and 0.5 to 5 parts by weight of a dispersing agent are contained relative to 100 parts by weight of an exothermic paste composition and,
Wherein the mixed binder is a mixture of epoxy acrylate or hexamethylene diisocyanate, polyvinyl acetal, and phenolic resin. The method according to claim 1,
Wherein the mixed binder is a mixture of 10 to 150 parts by weight of a polyvinyl acetal resin and 100 to 500 parts by weight of a phenolic resin based on 100 parts by weight of epoxy acrylate or hexamethylene diisocyanate. The method according to claim 1 or 2,
And 0.5 to 5 parts by weight of a silane coupling agent per 100 parts by weight of the exothermic paste composition. The method according to claim 1 or 2,
Wherein the carbon nanotube particles are multi-walled carbon nanotube particles. The method according to claim 1 or 2,
The organic solvent is selected from among carbonitol acetate, butyl carbitol acetate, DBE (dibasic ester), ethyl carbitol, ethyl carbitol acetate, dipropylene glycol methyl ether, cellosolve acetate, butyl cellosolve acetate, butanol and octanol Wherein the heat-generating paste composition is a mixed solvent of at least two solvents selected from the group consisting of water, A surface heating element formed by screen printing, gravure printing or comma coating on a substrate, according to claim 1 or 2. The method of claim 6,
Wherein the substrate is a polyimide substrate, a glass fiber mat, or a ceramic glass. The method of claim 6,
And a protective layer formed on the upper surface of the planar heating element and formed of an organic material having a black pigment such as silica or carbon black. A portable heating heater comprising the planar heating element according to claim 8 and a power supply part for supplying electric power to the planar heating element.

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