KR102231216B1 - Method for producing heat-generating composite material using metal-coated carbon fiber and the heat-generating composite material thereby - Google Patents

Abstract

The present invention relates to a manufacturing method of a heating composite material using a metal-coated carbon fiber, the heating composite material manufactured by the same, a molded body including the heating composite material, and a heating product including the molded body. The heating composite material of the present invention is manufactured by impregnating a bundle of the metal-coated carbon fibers with a resin, and the heating composite material has excellent heating performance.

Description

[Method for producing heat-generating composite material using metal-coated carbon fiber and the heat-generating composite material thereby}

The present invention relates to a method of manufacturing a heating composite material using a metal-coated carbon fiber, a heating composite material manufactured by the above manufacturing method, a molded body including the heating composite material, and a heating product including the molded body.

The market related to heating products can be applied to all products that generate heat by heating elements for building heating, heating elements for saunas and steamers, drying agricultural and marine products, and industrial heating elements.In recent years, efficient use of energy is possible in indoor floors, gardening, bedding, health appliances, and livestock houses. Hazardous heating sheets are being used on an increasing trend.

Heat-generating composite materials can be used in various household goods such as electronic products, heating supplies, household goods, medical supplies, beauty supplies, functional clothing, etc. that require a constant temperature as a plate type, assembly type, film, or sheet. This product is mainly used for industrial thermostats.

The range of heating composite materials is expanding in the field of heating for construction, and its application range is gradually expanding due to the advantage of having a high calorific value and being able to quickly control heating compared to existing on-board heating elements. In the field of high-temperature heating elements, metal heating wires and ITO nanoparticle heating elements are currently mainly applied, and the scope of application is limited due to the structure of the heating element, high process cost, and temperature constraints.

Heating composite materials are currently in the industrial demand for high-temperature heating elements such as air conditioning systems, air cleaning systems, auxiliary heating devices, etc., and have the advantage of having sufficient competitiveness compared to other heating elements because they can be applied to various substrates through inexpensive coating methods. have.

In addition, as the use of rechargeable batteries increases in the future along with the spread of electric and hybrid vehicles, the market for high-efficiency planar heating elements is expected to increase rapidly to improve battery efficiency. It is expected that the technology will be applied and utilized in various fields such as rubber.

The market for heating products in Korea is estimated at several trillion won, and in the case of heating products for buildings and transportation, electric stoves, electric blankets, electric heaters, electric heaters, etc. form a major product line, and a market worth 2~300 billion won per year. Is forming.

Currently, the planar heating element is partially used for heating products due to the limitation of low-temperature heating temperature, and it is forming a domestic market of 20 billion won per year, and it is expected to increase the size of the market when developing high-efficiency heating products in the future.

The heating composite material is manufactured by extruding it into a film shape in a state where the material is manufactured to maintain a constant electrical resistance by appropriate mixing and dispersion using nichrome wire, carbon fiber, carbon nanotube (CNT), ceramic powder, etc. on an existing metal plate. In order to uniformly disperse the mixed material on a metal or plastic support plate, it is manufactured by bonding it in various ways and applying electricity at a certain distance to generate heat. Here, in order to protect the mixed material for heat generation, a method of manufacturing a heating film having a multilayer by additionally adhering different materials is mainly used.

Meanwhile, as the price of coal in China and other countries rises, the burden on heating costs is increasing, and the problem of environmental pollution using coal is increasing, so the demand for heating products using heating films is increasing, and as the industry gradually develops. As the demand for heating films in the above-listed fields gradually increases, the importance of heating films, which consumes less power and lowers manufacturing costs, is expected to increase.

Republic of Korea Patent No. 1755924

The present invention is to solve the necessity of the prior art as described above, and an object of the present invention is to provide a heat-generating composite material manufactured by impregnating a resin into a metal-plated carbon fiber bundle and a method for manufacturing the same.

However, the technical problem to be achieved by the present invention is not limited to the problems mentioned above, and other problems that are not mentioned will be clearly understood by those skilled in the art from the following description.

In order to solve the above problems, the present invention provides a method of manufacturing a heating composite material using a metal-coated carbon fiber, including the following steps.

Manufacturing a metal-coated carbon fiber (S1);

Passing the bundle of carbon fibers prepared in step S1 through a resin impregnation tank to prepare a resin-impregnated metal coated carbon fiber (S2);

Curing the impregnated resin by cooling the carbon fiber prepared in step S2 (S3);

Drying the carbon fiber cured in the step S3 (S4); And

The step of manufacturing a heat-generating composite material by cutting the carbon fiber dried in step S4 into a predetermined length and pelletizing it (S5).

In one embodiment of the present invention, the step S1,

Electroless plating of carbon fibers with a first metal (S1-1); And

The carbon fiber electrolessly plated in step S1-1 may be electroplated with a second metal (S1-2).

In another embodiment of the present invention, the bundle of carbon fibers in step S2 may include 100 to 50,000 strands of monofilament.

In another embodiment of the present invention, the impregnation in step S2 may be performed in a resin impregnation tank in which the resin is extruded at a pressure of ^{0.5 to 10 kg/cm 2.}

In another embodiment of the present invention, the resin is polyamide (PA), polyethylene (PE), polypropylene (PP), acrylonitrile butadiene styrene (ABS), polycarbonate (PC), polyvinyl chloride (PVC) , Polyvinyl alcohol (PVA), polystyrene (PS), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polymethyl methacrylate (PMMA), acrylonitrile-styrene copolymer resin (SAN), At least one thermoplastic resin selected from the group consisting of acrylonitrile-styrene-acrylate copolymer resin (ASA), polyphenylene ether (PPE), polyphenylene sulfide (PPS), and polyether ether ketone (PEEK) It can be.

In another embodiment of the present invention, the heating composite material may include 5 to 40% by weight of metal-coated carbon fiber and 60 to 95% by weight of resin.

In another embodiment of the present invention, the drying in step S4 may be performed through air pressure applied at a pressure of ^{1 to 10 kg/cm 2 or hot air of 100° C. to 150° C.}

In another embodiment of the present invention, the pelletization of step S5 may be to cut the dried carbon fiber into a length of 1 to 15 mm.

In another embodiment of the present invention, the resin may further include one or more materials selected from the group consisting of metals, carbon nanotubes, and graphene.

In addition, the present invention provides a heat generating composite material manufactured by the above manufacturing method.

In addition, the heat generating composite material is melted and then injected into a mold to provide a molded body.

In addition, the molded body; And it provides a heating product that includes an electrode.

The present invention relates to a method of manufacturing a heat-generating composite material including a metal-coated carbon fiber impregnated with a resin, a molded article manufactured through the heat-generating composite material, and a heat generating product including the molded article, according to the manufacturing method of the present invention. , The metal-coated carbon fiber inside the heating composite material is included in a certain arrangement and length, so that the electrical resistance of the heating composite material can be easily controlled.

In addition, since the heat generating composite material of the present invention can be easily commercialized by a molding method through a general injection method, it is possible to easily commercialize a complex shape in a single process. It has the advantage of being easy to manufacture products according to etc.

1 is a diagram schematically illustrating a method of manufacturing a heat generating composite material of the present invention, a method of manufacturing a molded body using the heat-generating composite material, and a method of manufacturing a heat generating product using the molded body.
2 is a schematic view showing a manufacturing apparatus for manufacturing a heat generating composite material of the present invention.
3 is a view showing a heat-generating composite material of the present invention and a cross-section thereof.
4 is a view showing a test piece for measuring the amount of heat generated by connecting an electrode to the molded article of the present invention.
5 is a result of measuring the heating temperature generated by varying the amount of power input to the test piece of the present invention, FIG. 5A is a thermal image result measured by applying power at 0.5V and 0.89A, and FIG. 5B is 1.0V and 1.8. A thermal image result measured by applying power to A, FIG. 5C is a thermal image result measured by applying power at 1.5V and 2.6A, and FIG. 5D is a thermal image measured by applying power at 2.0V and 3.41A. 5E is a thermal image result measured by applying power at 2.5V and 3.92A, FIG. 5F is a thermal image result measured by applying power at 3.0V and 4.36A, and FIG. 5G is 3.5V and 4.63 It is a diagram showing the result of a thermal image measured by applying power to A.

Hereinafter, the description of the present invention is not limited to a specific embodiment, and various transformations may be applied and various embodiments may be provided. In addition, the content described below should be understood to include all conversions, equivalents, and substitutes included in the spirit and scope of the present invention.

The singular expression used in the present invention includes a plurality of expressions unless the context clearly indicates otherwise. In addition, terms such as "comprise", "include" or "have" described below are intended to designate the presence of features, numbers, steps, actions, components, parts, or combinations thereof described in the specification. It is to be construed and not to preclude the possibility of the presence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

Hereinafter, the present invention will be described in detail.

In the present invention, as a result of intensive research to manufacture a heat-generating composite material that is easy to commercialize at the same time with excellent heat-generating performance, when producing a pellet-type heat-generating composite material by impregnating a resin in a bundle-type metal-coated carbon fiber, the heat-generating performance The present invention was completed by confirming that a heat-generating composite material excellent in both and physical properties is manufactured, and can be easily manufactured as a heat-generating product through the heat-generating composite material. The method of manufacturing a heating composite material according to the present invention, and a process of manufacturing a heating product by injection molding the heating composite material, printing and assembling electrodes, are schematically shown in FIG. 1.

That is, the present invention provides a method of manufacturing a heat-generating composite material using a metal-coated carbon fiber, comprising the following steps:

Manufacturing a metal-coated carbon fiber (S1);

Passing the bundle of carbon fibers prepared in step S1 through a resin impregnation tank to prepare a resin-impregnated metal coated carbon fiber (S2);

Curing the impregnated resin by cooling the carbon fiber prepared in step S2 (S3);

Drying the carbon fiber cured in the step S3 (S4); And

The step of manufacturing a heat-generating composite material by cutting the carbon fiber dried in step S4 into a predetermined length and pelletizing it (S5).

The present invention, as schematically shown in Figure 2, relates to a method of manufacturing a heat-generating composite material manufactured by impregnating a thermoplastic resin between fiber bundles by pressure using a metal-coated carbon fiber (MCF). The metal-coated carbon fiber used in the present invention can be used without limitation as long as it is a carbon fiber coated with a metal through a plating process on the outer diameter of the carbon fiber. However, in order to satisfy the heating performance to be manufactured in the present invention, electroless plating And it is preferable to use a carbon fiber coated with a metal double through electrolytic plating.

More specifically, the step S1 may include electroless plating of carbon fibers with a first metal (S1-1); And electroplating the carbon fiber electrolessly plated in step S1-1 with a second metal (S1-2). The types of the first metal and the second metal may be the same or different from each other, and preferably, the first metal may be nickel or copper, and the second metal may be nickel. The electroless and electrolytic process of the present invention may be performed through the method disclosed in Korean Patent No. 1427309, but is not limited thereto.

The step S1-1 may be plated by passing carbon fibers through an electroless plating solution containing pure water, a first metal salt, a complexing agent, a reducing agent, a stabilizer, and a pH adjusting agent, and the step S1-2 is S1 It is performed continuously following step -1, and may be performed by applying a constant voltage (CV) of 5-15 Volt using a second metal salt and a pH buffer, but is not limited to the method.

Prior to the steps S1-1 and S1-2, (i) degreasing and softening the carbon fibers by passing the carbon fibers through an aqueous solution containing a surfactant, an organic solvent, and a nonionic surfactant; (Ii) The carbon fiber resulting from step (i) was used as sodium bisulfite (NaHSO ₃ ), sulfuric acid (H ₂ SO ₄ ), ammonium persulfate ((NH ₄ ) ₂ S ₂ O ₈ ) And performing an etching process for neutralizing, cleaning and conditioning by passing through an aqueous solution containing pure water. (Iii) performing a sensitizing process by passing the carbon fiber resulting from step (ii) _{through an aqueous PdCl 2 solution;} And (iv) passing the carbon fiber resulting from step (iii) _{through an aqueous solution of sulfuric acid (H 2} SO ₄ ) to perform an activating process. Fiber may be used, but is not limited thereto.

The thickness of the metal coating produced by the plating may be 50 to 500 nm. Depending on the thickness of the metal coating, the electric resistance of the metal coated carbon fiber may be different, and the preferable electric resistance may be 0.1 to 10 Ω/m, but is not limited thereto.

In step S2 of the present invention, the carbon fibers are characterized in that they are in the form of bundles. The bundle of carbon fibers includes 100 to 50,000 strands of monofilament, preferably 1K (1,000 strands of monofilament), 3K (3,000 strands of monofilament), 6K (6,000 strands of monofilament), 12K (12,000 monofilament strands) ), 48K (monofilament 48,000 strands) can be used, and more preferably 8K (monofilament 8,000 strands) to 16K (monofilament 16,000) of carbon fibers can be used, the present invention As in the example, a 12K carbon fiber bundle may be used.

The metal-coated carbon fiber may be provided in a form wound around a bobbin, and transferred to a resin impregnation tank through a fiber guide roller. The fiber guide roller is used to minimize the frictional force to reduce the peeling of the metal coating layer, and the guide roller may be further provided between the resin impregnation tank and the cooling unit in which the resin is cured, as shown in FIG. 2.

The step S2 of the present invention is a step of impregnating a resin into the bundle of carbon fibers. The impregnation may be performed in a resin impregnation tank in which the resin is extruded at a pressure of 0.5 to 10 kg/cm ^2. The resin is a thermoplastic resin, such as polyamide resin (PA6, PA66, etc.), polyethylene (PE), polypropylene (PP), acrylonitrile butadiene styrene (ABS), polycarbonate (PC), polyvinyl chloride (PVC), Polyvinyl alcohol (PVA), polystyrene (PS), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polymethyl methacrylate (PMMA), acrylonitrile-styrene copolymer resin (SAN), acrylic Ronnitrile-styrene-acrylate copolymer resin (ASA), polyphenylene ether (PPE), polyphenylene sulfide (PPS), polyether ether ketone (PEEK), and the like may be used. The polyamide may have a density of 1.14 g/cm ³ , a melting point of 220 to 255 °C, a tensile strength of 83 to 85 MPa, an Izod impact strength of 7.0 to 7.5 Kg ^f ·cm/cm, and a heat deflection temperature of 65 to 85 °C, but limited thereto. It does not become.

The resin is heated in the range of 100 to 500 ℃ in consideration of the melting point, and the melted one is extruded into a resin impregnation tank through a resin extruder. The resin impregnation amount is adjusted in consideration of the cross-sectional area of the fiber, and the pressure can be adjusted by adjusting the diameter size of the resin extruder. It is more preferable that the pressure is 1 to 3 kg/cm ² in terms of the cross-sectional area of the bundle of carbon fibers to be used.

The heating composite material of the present invention may include 5 to 40% by weight of metal-coated carbon fiber and 60 to 95% by weight of resin. More preferably, when containing 25 to 35% by weight of the metal-coated carbon fiber and 75 to 65% by weight of the resin, it may be made of a heat-generating composite material having desirable heat-generating performance for use in heat-generating products.

The drying in step S4 may be performed through air pressure applied at a pressure of 1 to 10 kg/cm ² or hot air at 100° C. to 150° C., but the method of drying is the type of resin used and the process being performed. It can be freely selected and performed according to the environment. When drying of the resin is completed, the carbon fiber may be transferred to the pelletizer through a drawing device. The pull-out device is a roller-type device that pulls the material in which the fiber and the impregnating resin are combined, and a urethane or rubber roller having high friction may be used.

The pelletization of step S5 may be performed by cutting the dried carbon fiber into a length of 1 to 15 mm. More preferably, it may be provided in a length of 4mm to 8mm, which is an easy size to be injected into the mold when injection-molded.

The resin of the present invention may further include one or more materials selected from the group consisting of metals, carbon nanotubes, and graphene according to the characteristics of the heating product to be manufactured. There is no limitation on the type of the metal.

The present invention provides a heat generating composite material manufactured by the above manufacturing method. The pelletized heat generating composite material may be melted and then injected into a mold to be molded into a desired shape to be manufactured into a molded body. The molded body may be added by mixing different types of pellets in order to control the color of the product, the flowability of the liquid, and the dispersibility of the fibers.

The present invention can complete the heating product by assembling the electrode so that electric power can be applied to the molded body. At this time, in consideration of the electric resistance to the electrode distance of the heating composite material, the power input unit can be designed/manufactured, and the design/manufacturing method is freely selected according to the type, shape, and environment used of the heating product to be manufactured. So it can be designed/manufactured.

The electrode is a conductive material, and may be at least one selected from the group consisting of copper, silver (Ag), gold (Au), carbon nanotubes (CNT), and graphene. After producing electrodes in the form of printing using a conductive material on the molded body or inserting it into the molded body by heat-sealing by heating the surface, the heating product can be completed by assembling a connection connector.

Hereinafter, the present invention will be described in more detail through examples. These examples are only for describing the present invention in more detail, and it will be apparent to those of ordinary skill in the art that the scope of the present invention is not limited by these examples.

[Example]

Example 1. Preparation of heating composite material

1.1. Check the electrical resistance of metal-coated carbon fiber by coating thickness

Using 12K carbon fiber, a metal-coated carbon fiber (MCF) was manufactured by the method of manufacturing a metal-plated carbon fiber according to Registration Patent No. 1427309. By making the metal coating thickness different from each other, Samples-1 to 4 shown in Table 1 below were prepared.

Metal coating thickness Fiber specific gravity Fiber electrical resistance
(Ω/m) Sample-1 100 nm 2.13 4 Sample-2 130 nm 2.24 3 Sample-3 190 nm 2.45 2 Sample-4 360 nm 3.0 One

As shown in Table 1, different fiber electrical resistance was observed depending on the thickness of the metal coating. In the following examples, Sample-3 was used.

1. 2. Properties of Polyamide Resin

The resin shown in Table 2 below was prepared as a resin impregnated with the metal-coated carbon fiber.

density
(g/cm ³ ) Melting point
(℃) The tensile strength
(MPa) Izod impact strength
(Kg ^f cm/cm) Heat deflection temperature
(℃) PA6 1.14 220 83 7.5 65 PA66 1.14 255 85 7.0 85

In the following examples, among the resins, PA6 was selected and used.

1.3. Manufacturing of heat-generating composite materials

Using the manufacturing apparatus shown in FIG. 2, the 12,000 strands of MCF fibers of Sample-3 were uniformly impregnated with PA6 resin to make the composite material into a linear shape and cut it into a length of 6 mm to prepare a pellet.

As shown in FIG. 3, the pellet has a form in which a resin is impregnated between the fiber bundles.

Example 2. Manufacture of molded body of heating composite material

The pellets of Example 1 were melted in an injection molding machine to prepare a Plate product (size: 6 mm (T) x 12 mm (W) x 100 mm, volume: 7.2 cm ³ ).

The electrical resistance according to the amount of the resin impregnated was measured, and is shown in Table 3 below.

Sample MCF PA 6 Electrical resistance Ω/cm ³ One 10% 90% 100 to 200 2 20% 80 50 to 100 3 30% 70 15 to 40 4 40% 60 5 to 10

Example 3. Preparation of test piece to which electrodes are connected

In this Example 3, in order to manufacture a heating product with an electrode connected, a pellet containing 30% by weight of MCF fiber and 70% by weight of a resin was melted and put into a mold, and then 16 mm (T) x 12 mm (W) x 100 mm. To prepare a test piece.

As shown in FIG. 4, in order to manufacture the power input part in the manufactured test piece, copper wires were heat-sealed and inserted at both ends to produce a power input part.

A DC power injector was connected to the test piece, and the heating temperature was measured with a thermal imaging camera 10 seconds after the power was applied, and are shown in FIGS. 5A to 5G.

Through the results of FIG. 5, it was confirmed that it is possible to easily control the heating temperature according to the amount of power input.

Although the preferred embodiments of the present invention have been described in detail above, the rights of the present invention are not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

Claims (12)

Manufacturing a metal-coated carbon fiber (S1);
Passing the bundle of carbon fibers prepared in step S1 through a resin impregnation tank to prepare a resin-impregnated metal coated carbon fiber (S2);
Curing the impregnated resin by cooling the carbon fiber prepared in step S2 (S3);
Drying the carbon fiber cured in the step S3 (S4); And
Including the step (S5) of manufacturing a heat-generating composite material by cutting the carbon fiber dried in step S4 into a predetermined length and pelletizing it,
In the S2 step, the resin is polyamide (PA), the polyamide has a density of 1.14 g/cm ³ , a melting point of 220 to 255° C., a tensile strength of 83 to 85 MPa, and an Izod impact strength of 7.0 to 7.5 Kg ^f ·cm/cm , The heat deflection temperature is 65~85℃,
The resin is heated within the range of 100 to 500°C and the melted one is extruded into a resin impregnation tank through a resin extruder, and the impregnation is performed in a resin impregnation tank in which the resin is extruded at a pressure of ^{1 to 3 kg/cm 2,}
The heating composite material comprises 25 to 35% by weight of the metal-coated carbon fiber and 75 to 65% by weight of the resin,
Manufacturing method of heat-generating composite material using metal-coated carbon fiber
The method of claim 1,
The S1 step,
Electroless plating of carbon fibers with a first metal (S1-1); And
The method of manufacturing a heat-generating composite material using a metal-coated carbon fiber comprising the step of electroplating the carbon fiber electrolessly plated in step S1-1 with a second metal (S1-2).
The method of claim 1,
The bundle of carbon fibers in step S2 is that the monofilament contains 100 to 50,000 strands, a method of manufacturing a heat-generating composite material using a metal-coated carbon fiber.
delete delete delete The method of claim 1,
The drying of the step S4 is ^{performed through air pressure applied at a pressure of 1 to 10 kg/cm 2} or hot air at 100° C. to 150° C., a method of manufacturing a heat-generating composite material using metal-coated carbon fiber.
The method of claim 1,
The pelletization of the step S5 is to cut the dried carbon fiber to a length of 1 to 15 mm, the method of manufacturing a heat-generating composite material using a metal-coated carbon fiber.
The method of claim 1,
The resin further comprises at least one material selected from the group consisting of metal, carbon nanotubes, and graphene.
Heat-generating composite material manufactured by the manufacturing method of claim 1.
A molded article that is injected by melting the heat generating composite material of claim 10 and then injected into a mold.
The molded article of claim 11; And an electrode, a heating product.

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