Nonwoven fabric, composite material, and method for manufacturing the same containing carbon fiber for electromagnetic shielding.

Abstract

The present invention provides a nonwoven fabric with excellent electromagnetic shielding and tensile strength, as well as a cost-effective method for manufacturing the nonwoven fabric. It also provides a composite material containing the nonwoven fabric. [Solution] The present invention relates to a nonwoven fabric, composite material, and method for manufacturing the same, which contain carbon fibers plated with metals including nickel (Ni), copper (Cu), cobalt (Co), zinc (Zn), gold (Au), silver (Ag), chromium (Cr), tin (Sn), palladium (Pd), rhodium (Rh), iron (Fe), or combinations thereof. The composite material manufactured by mixing the carbon fiber nonwoven fabric of the present invention with a resin exhibits excellent physical properties such as tensile strength and electromagnetic wave shielding.

Description

[Technical Field]

[0001] The present invention relates to a nonwoven fabric containing carbon fibers, a composite material, and a method for producing the same. A composite material produced by mixing the carbon fiber-containing nonwoven fabric of this application with a resin can exhibit excellent physical properties such as tensile strength and electromagnetic wave shielding. [Background technology]

[0002] With the development of electronic products, electronic components are used in a wide range of fields, including mobile phones, smartphones, other electrical products, automobiles, and ships. These electronic components emit large amounts of harmful electromagnetic radiation, and this has led to malfunctions in various electronic devices and safety accidents, which are currently emerging as social problems.

[0003] To achieve this electromagnetic wave shielding, research is being conducted on new composite materials with functional properties that shield electromagnetic waves by adding materials such as carbon, metal, and ceramic to lightweight polymer composite materials.

[0004] As part of this research, it was found that plating carbon fibers before manufacturing the nonwoven fabric could produce a relatively efficient electromagnetic shielding function, but this not only increased the production cost of the fiber yarn, but also made it difficult to adjust the amount of plating, thus making it difficult to produce nonwoven fabric of the desired weight.

[0005] This necessitates a technology for manufacturing nonwoven fabrics that offer excellent electromagnetic shielding and tensile strength while also being cost-effective. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Registered Patent Gazette No. 10-2326797 of the Republic of Korea [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] The present invention has been made to solve the above problems, and aims to provide a composite material including a non-woven fabric excellent in electromagnetic wave shielding and tensile strength and a manufacturing method thereof, and to reduce the cost of manufacturing a non-woven fabric excellent in electromagnetic wave shielding and tensile strength.

[0008] However, the problems to be solved by the present invention are not limited to the problems mentioned above, and other problems to be solved not mentioned will be clearly understood by those having ordinary knowledge in the technical field to which the present invention pertains from the content described later.

Means for Solving the Problems

[0009] One aspect of the present application includes carbon fibers plated with a metal, The metal includes nickel (Ni), copper (Cu), cobalt (Co), zinc (Zn), gold (Au), silver (Ag), chromium (Cr), tin (Sn), palladium (Pd), rhodium (Rh), iron (Fe), or a combination thereof, and provides a non-woven fabric.

[0010] Another aspect of the present application includes a first step of introducing carbon fibers into a solvent to produce a carbon fiber dispersion liquid, a second step of producing a wet non-woven fabric including a step of drying the carbon fiber dispersion liquid, and a third step of dipping the produced wet non-woven fabric in a plating solution for plating. The manufacturing method of the non-woven fabric is provided.

[0011] Still another aspect of the present application includes a composite material including the non-woven fabric, and provides a composite material.

Effects of the Invention

[0012] The non-woven fabric and the composite material according to the present invention are excellent in electromagnetic wave shielding and tensile strength, can use recycled carbon fibers, and can economically produce a non-woven fabric for electromagnetic wave shielding of excellent quality. [Brief explanation of the drawing]

[0013] [Figure 1] This is a photograph of the nonwoven fabric from Manufacturing Example 1, observed using a scanning electron microscope (SEM). [Figure 2] Figures 2(a) and 2(b) are photographs of the plated nonwoven fabrics of Example 1 and Example 2, respectively, observed using an electron scanning microscope. [Modes for carrying out the invention]

[0014] The operation and effects of the invention will be described in more detail below through specific embodiments and drawings. However, these embodiments are presented merely as examples of the invention and do not define the scope of the invention's rights.

[0015] Prior to this, terms and words used in this specification and in the claims should not be interpreted in a manner limited to their ordinary or dictionary meanings, but rather in a manner consistent with the technical idea of ​​the present invention, in accordance with the principle that inventors may appropriately define the concepts of terms in order to best describe their invention.

[0016] Therefore, the configurations of the embodiments described herein represent only one of the most preferred embodiments of the present invention and do not represent the entire technical concept of the invention. It should be understood that, at the time of filing, there are various equivalents and modifications that can be substituted for these embodiments.

[0017] In this specification, singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as “includes,” “equip,” or “have” are intended to specify the presence of an implemented feature, number, stage, component, or combination thereof, and should be understood not to preemptively exclude the possibility of the presence or addition of one or more other features, numbers, stages, components, or combinations thereof.

[0018] Where, in this specification, various parameters are given as a list of ranges, preferred ranges, preferred upper limits, and preferred lower limits, it should be understood that all ranges formed by any pair of any upper range limits or preferred values, and any lower range limits or preferred values, are specifically disclosed, regardless of whether the ranges are disclosed separately.

[0019] Where a range of numbers is referred to herein, unless otherwise specified, that range is intended to include its endpoint and all integers and fractions within that range.

[0020] The scope of this invention is not intended to be limited to the specific values ​​mentioned when defining the range.

[0021] In this specification, the terms "from" and "~" in "a to b" and "a~b" which indicate a numerical range are defined as ≥ a and ≤ b.

[0022] The embodiments of the present application have been described in detail below, but the present application is not limited thereto.

[0023] A nonwoven fabric according to one embodiment of the present application may contain metal-plated carbon fibers, the metal of which may include nickel (Ni), copper (Cu), cobalt (Co), zinc (Zn), gold (Au), silver (Ag), chromium (Cr), tin (Sn), palladium (Pd), rhodium (Rh), iron (Fe), or a combination thereof.

[0024] In one embodiment of the present invention, the plating may be performed by an electroless plating method, an electroplating method, or a combination thereof.

[0025] For example, the carbon fibers can be plated once or more times by an electroplating method, or the carbon fibers can be plated once or more times by an electroless plating method, and the nonwoven fabric can be plated once or more times by an electroplating method after the electroless plating method.

[0026] Furthermore, the carbon fibers can be plated by repeating a cycle in which the electroless plating method is followed by the electroplating method.

[0027] In this case, the plating may be performed after the nonwoven fabric has been manufactured. That is, a nonwoven fabric manufactured using carbon fibers can be plated to form a plating on the carbon fibers.

[0028] In one embodiment of the present invention, carbon fibers can be copper plated by an electroless method, and nickel plating may be additionally formed by an electroplating method after the copper plating.

[0029] In one embodiment of the present invention, the weight increase rate of the nonwoven fabric after plating may be 10% or more.

[0030] At this time, the method for measuring the weight increase rate of the nonwoven fabric after plating may be according to Equation 1 below. <Expression 1> Weight increase rate of nonwoven fabric [%] = [(Weight of nonwoven fabric after plating - Weight of nonwoven fabric before plating) / Weight of nonwoven fabric before plating] × 100

[0031] For example, the weight increase rate of the nonwoven fabric after plating may be 10% to 70%, 20% to 65%, 30% to 60%, or 40% to 55%.

[0032] When the weight increase rate of the non-woven fabric after plating is less than 5%, the electromagnetic wave shielding effect and the tensile strength of the non-woven fabric may not be sufficient.

[0033] In one embodiment of the present application, the basis weight of the non-woven fabric before plating is 10 g / m 2 or more and 200 g / m 2 or less, and the basis weight of the non-woven fabric after plating may be 11 g / m 2 or more and 1,000 g / m 2 or less.

[0034] For example, the basis weight of the non-woven fabric before plating is 15 g / m 2 or more and 190 g / m 2 or less, 10 g / m 2 or more and 180 g / m 2 or less, 25 g / m 2 or more and 170 g / m 2 or less, 30 g / m 2 or more and 160 g / m 2 or less, 35 g / m 2 or more and 150 g / m 2 or less, 40 g / m 2 or more and 140 g / m 2 or less, 45 g / m 2 or more and 130 g / m 2 or less, 50 g / m 2 or more and 120 g / m 2 or less, 55 g / m 2 or more and 110 g / m 2 or less, 60 g / m 2 or more and 100 g / m 2 or less, or 70 g / m 2 or more and 90 g / m 2 or less.

[0035] For example, the basis weight of the non-woven fabric after plating is 11 g / m 2 or more and 1,000 g / m 2 or less, 20 g / m 2 or more and 900 g / m 2 or less, 30 g / m 2 or more and 800 g / m 2 or less, 40 g / m 2 or more and 700 g / m 2 or less, 50 g / m2 More than 600g / m 2 Below 60g / m 2 More than 500g / m 2 Below 70g / m 2 More than 400g / m 2 Below 80g / m 2 More than 300g / m 2 Below 90g / m 2 More than 200g / m 2 Below 100g / m 2 More than 150g / m 2 The following is also acceptable.

[0036] For example, a pre-plating basis weight of 80 g / m² manufactured using carbon fiber is 80 g / m². 2 When nonwoven fabric is plated, the basis weight of the plated nonwoven fabric is 110 g / m². 2 More than 130g / m 2 The following is also acceptable.

[0037] In one embodiment of the present invention, the carbon fiber may include pitch-based, poly acrylic nitrogen (PAN)-based, rayon-based, or a combination thereof.

[0038] In one embodiment of the present application, the carbon fiber may include recycled carbon fiber. However, the carbon fiber is not limited to recycled carbon fiber and may include virgin carbon fiber, recycled carbon fiber, or a combination thereof.

[0039] In one embodiment of the present invention, the average length of the carbon fibers may be 20 mm or more.

[0040] For example, the average length of the carbon fibers may be 20 mm to 200 mm, 25 mm to 170 mm, 30 mm to 140 mm, 35 mm to 110 mm, 40 mm to 80 mm, or 45 mm to 60 mm.

[0041] In this case, if the average length of the carbon fibers exceeds that of the present invention, the dispersibility may decrease, which may result in the nonwoven fabric having uneven tensile strength and electrical conductivity. Furthermore, if the average length of the carbon fibers falls below that of the present invention, it may be difficult to ensure sufficient wet strength, which may result in the carbon fibers of the nonwoven fabric becoming defibrous when plated.

[0042] When a nonwoven fabric is manufactured using carbon fibers of the average length of the present invention, the bonding force between the carbon fibers is strong and the wet strength is excellent. As a result, it is possible to omit the use of a binder or reduce the binder content, and the nonwoven fabric can be manufactured at a relatively low cost.

[0043] In one embodiment of the present invention, the nonwoven fabric may have an electromagnetic shielding level of 30 dB or more as measured according to ASTM-D4935.

[0044] For example, electromagnetic shielding measured according to ASTM-D4935 may be between 40 dB and 100 dB, between 45 dB and 99 dB, between 50 dB and 98 dB, between 55 dB and 97 dB, between 60 dB and 96 dB, or between 65 dB and 95 dB.

[0045] When electromagnetic waves are shielded using the nonwoven fabric of the present invention, the intensity of the electromagnetic waves after shielding may be at a level of 1 / 1,500,000 (1 / 1,500,000) to 1 / 500,000 (1 / 500,000), relative to the intensity of the electromagnetic waves before shielding.

[0046] For example, the intensity of electromagnetic waves after shielding may be 1 / 1.4 million to 1 / 600,000, 1 / 1.3 million to 1 / 700,000, 1 / 1.2 million to 1 / 800,000, or 1 / 1.1 million to 1 / 900,000, based on the intensity of electromagnetic waves before shielding.

[0047] In this case, the electromagnetic shielding of the nonwoven fabric can be said to represent the average value of the degree of electromagnetic shielding measured at 30 MHz to 1.5 GHz based on ASTM-D4935.

[0048] In other words, the nonwoven fabric of this invention can exhibit excellent electromagnetic wave shielding capabilities in the high-frequency range.

[0049] In one embodiment of the present invention, the nonwoven fabric may have a tensile strength of 5 MPa or more, as measured according to KS K ISO 9073-3.

[0050] For example, the tensile strength of the nonwoven fabric measured according to KS K ISO 9073-3 may be 20 MPa to 200 MPa, 50 MPa to 195 MPa, 80 MPa to 190 MPa, 110 MPa to 185 MPa, or 140 MPa to 180 MPa.

[0051] Nonwoven fabrics with tensile strength below the range specified in this application may not be able to achieve sufficient wet strength, which could lead to problems such as the inability to plate them.

[0052] A method for manufacturing a nonwoven fabric according to another aspect of the present invention may include a first step of preparing a carbon fiber dispersion by adding carbon fibers to a solvent; a second step of preparing a wet nonwoven fabric, which includes drying the carbon fiber dispersion; and a third step of plating the prepared wet nonwoven fabric by immersing it in a plating solution.

[0053] In one embodiment of the present application, the first step may include the step of adding binder fibers, binder polymers, or a combination thereof.

[0054] The aforementioned binder fibers or binder polymers are used to increase the bonding strength of the nonwoven fabric after the drying step during the manufacturing of the nonwoven fabric, and may be, for example, polyvinyl alcohol (PVA) fibers, low-melting-point polyester (LMPET) fibers, or polyvinyl alcohol resin.

[0055] Based on a total carbon fiber dispersion content of 100% by weight, the binder fibers may be contained in an amount of 0.001% by weight or more and 5% by weight or less.

[0056] If the content of the binder fibers falls below the aforementioned range, satisfactory strength may not be achieved.

[0057] In one embodiment of the present application, the first step may include adding a wetting agent, the wetting agent may include a cationic surfactant, an anionic surfactant, a nonionic surfactant, or a combination thereof.

[0058] For example, the wetting agent may be an EO (ethylene oxide) / PO (propylene oxide) copolymer surfactant, a PEO (polyethylene oxide)-based surfactant, a PEG (polyethylene glycol)-based surfactant, or a combination thereof.

[0059] In one embodiment of the present application, the plating solution may include nickel (Ni), copper (Cu), cobalt (Co), zinc (Zn), gold (Au), silver (Ag), chromium (Cr), tin (Sn), palladium (Pd), rhodium (Rh), iron (Fe), or a combination thereof.

[0060] In one embodiment of the present invention, the plating method in the third step may be an electroless plating method, an electroplating method, or a combination thereof.

[0061] For example, the nonwoven fabric can be plated once or more times by an electroplating method, or by an electroless plating method, and the nonwoven fabric can be plated once or more times by an electroless plating method followed by an electroplating method.

[0062] Furthermore, the nonwoven fabric can be plated by repeating a cycle in which the electroless plating method is followed by the electroplating method.

[0063] In one embodiment of the present invention, the acidity (pH) of the electroless plating solution may be 3 to 15.

[0064] The acidity of the plating solution in the electroless plating method may vary depending on the metal.

[0065] For example, the appropriate acidity for electroless plating using nickel metal may be 4.0 to 7.0, the appropriate acidity for electroless plating using copper metal may be 11.0 to 13.0, the appropriate acidity for electroless plating using silver may be 8.0 to 10.0, and the appropriate acidity for electroless plating using gold may be 6.0 to 8.0.

[0066] The aforementioned appropriate acidity may be one of the factors that properly maintain the reaction between metal ions and reducing agents. That is, when plating proceeds within the range of the aforementioned appropriate acidity, it can help maintain the balance of the chemical reaction in the plating solution.

[0067] If the acidity of the plating solution exceeds or falls below the appropriate acidity for each metal, the plating bath may become unstable, precipitates may form in the plating bath, and the components of the plating solution may deteriorate.

[0068] Furthermore, if the acidity level exceeds or falls below the appropriate level for each metal, the plating speed may be excessively fast or slow, which could prevent the formation of a uniform plating layer.

[0069] Furthermore, if the acidity exceeds the appropriate level for each metal, an excessive plating reaction may occur, and impurities may be present in the plating formed during this process. Conversely, if the acidity falls below the appropriate level for each metal, precipitation of metal ions may not occur, and the plating may not be sufficiently formed.

[0070] The acidity of the plating solution for the electroless plating method can be adjusted using, but is not limited to, sulfuric acid (H2SO4), hydrochloric acid (HCl), acetic acid (CH3COOH), nitric acid (HNO3), phosphoric acid (H3PO4), hydrogen sulfide (H2S), sodium hydroxide (NaOH), ammonia (NH3), potassium hydroxide (KOH), sodium carbonate (Na2CO3), ammonium hydroxide (NH4OH), potassium carbonate (K2CO3), or a combination thereof.

[0071] In one embodiment of the present invention, the temperature of the plating solution in the electroless plating method may be 10°C to 100°C.

[0072] The temperature of the plating solution in the electroless plating method may vary depending on the metal.

[0073] For example, the appropriate plating solution temperature for electroless plating using nickel metal may be 85°C to 95°C, the appropriate plating solution temperature for electroless plating using copper metal may be 20°C to 40°C, the appropriate plating solution temperature for electroless plating using silver may be 30°C to 50°C, and the appropriate plating solution temperature for electroless plating using gold may be 50°C to 70°C.

[0074] If the temperature of the plating solution in the electroless plating method exceeds the appropriate temperature range for each metal, the rate at which the plating is formed may be excessively fast, resulting in an unevenly formed plating layer or defects in the formed plating layer. If the temperature of the plating solution in the electroless plating method falls below the appropriate temperature range for each metal, the plating rate may be slow, the reaction for forming the plating may not be carried out sufficiently, and the density of the formed plating layer may be lower than the target plating density.

[0075] In one embodiment of the present invention, the electroless plating method may be performed for 10 minutes to 1 hour.

[0076] For example, the time required for the electroless plating method may be 15 minutes or more and 55 minutes or less, 20 minutes or more and 50 minutes or less, 23 minutes or more and 45 minutes or less, 25 minutes or more and 40 minutes or less, or 27 minutes or more and 35 minutes or less.

[0077] The time required for the electroless plating method described above can be set differently depending on the desired thickness of the plating layer.

[0078] In this case, the longer the electroless plating method is performed, the thicker the plated layer formed will be. Even if the desired thickness of the plated layer is the same, the time required to form the desired thickness of the plated layer may differ depending on the metal ion concentration of the plating solution, the temperature of the plating solution, and the acidity of the plating solution.

[0079] If the time for the electroless plating method exceeds the time specified in this invention, the resulting plating layer may have a rough or uneven surface, resulting in low quality. If the time for the electroless plating method falls below the range specified in this invention, the plating may not be sufficiently formed.

[0080] At this time, the time for which the electroless plating method is performed can be set differently depending on the desired thickness of the plating layer, the concentration of the plating solution, the temperature of the plating solution, the acidity (pH) of the plating solution, or a combination thereof.

[0081] For example, if the concentration of the plating solution is low, the plating process may take a long time. Similarly, if the temperature or acidity of the plating solution is not optimized for plating, the plating process may take longer or the plating may not form properly.

[0082] In one embodiment of the present invention, the acidity (pH) of the electroplating solution may be 0.5 to 15.

[0083] The acidity of the plating solution in the electroplating method described above may vary depending on the metal.

[0084] For example, the appropriate acidity for electroplating using nickel metal may be 4.0 to 5.5, the appropriate acidity for electroplating using copper metal may be 0.5 to 3.0 or 8.5 to 12.0, the appropriate acidity for electroplating using silver may be 9.0 to 10.5, the appropriate acidity for electroplating using gold may be 4.0 to 6.0, the appropriate acidity for electroplating using zinc may be 4.5 to 5.5 or 12.0 to 14.0, and the appropriate acidity for electroplating using chromium may be 1.0 to 2.5.

[0085] If the acidity of the plating solution in the aforementioned electroplating method exceeds or falls below the appropriate acidity for each metal, the plating speed may be excessively fast or slow. This may result in an inability to form a uniform plating layer, and thus a decrease in the quality of the resulting plating.

[0086] The acidity of the plating solution in the aforementioned electroplating method can be adjusted using, but is not limited to, sulfuric acid (H2SO4), hydrochloric acid (HCl), acetic acid (CH3COOH), nitric acid (HNO3), phosphoric acid (H3PO4), hydrogen sulfide (H2S), sodium hydroxide (NaOH), ammonia (NH3), potassium hydroxide (KOH), sodium carbonate (Na2CO3), ammonium hydroxide (NH4OH), potassium carbonate (K2CO3), or a combination thereof.

[0087] In one embodiment of the present invention, the temperature of the electroplating solution may be 10°C to 80°C.

[0088] The temperature of the plating solution in the electroplating method may vary depending on the metal.

[0089] For example, the appropriate plating solution temperature for electroplating using nickel metal may be 50°C to 60°C, the appropriate plating solution temperature for electroplating using copper metal may be 20°C to 60°C, the appropriate plating solution temperature for electroplating using silver may be 20°C to 30°C, the appropriate plating solution temperature for electroplating using gold may be 50°C to 70°C, the appropriate plating solution temperature for electroplating using zinc may be 20°C to 40°C, and the appropriate plating solution temperature for electroplating using chromium may be 45°C to 60°C.

[0090] In this case, the appropriate temperature range for the plating solution during electroplating may vary depending on the acidity of the plating solution.

[0091] For example, if the plating solution is acidic, the appropriate plating solution temperature for electroplating using the copper metal may be 20°C to 30°C, and if the plating solution is alkaline, the appropriate plating solution temperature for electroplating using the copper metal may be 50°C to 60°C.

[0092] For example, if the plating solution is acidic, the appropriate plating solution temperature for electroplating using zinc may be 20°C to 30°C, and if the plating solution is alkaline, the appropriate plating solution temperature for electroplating using zinc may be 20°C to 40°C.

[0093] If the temperature of the plating solution in the electroplating method is high, the plating can proceed quickly, but if it exceeds the scope of this invention, defects may occur in the formed plating layer or the plating solution may be unstable.

[0094] If the temperature of the plating solution in the electroplating method described above is lower than that of the present invention, the resulting plating layer may be non-uniform and the plating speed may be slow.

[0095] In one embodiment of the present invention, the electroplating method may be performed for 5 to 120 minutes.

[0096] At this time, the time required to perform the electroplating method may vary depending on the type of metal.

[0097] For example, the time required for the electroplating method described above may be 6 minutes or more and 25 minutes or less, 7 minutes or more and 20 minutes or less, 8 minutes or more and 15 minutes or less, or 9 minutes or more and 12 minutes or less.

[0098] The time required for the electroplating method described above may vary depending on the type of metal.

[0099] If the plating time of the electroplating method described above exceeds or falls below the scope of this invention, the plating may not be sufficiently formed or the plating may not be uniform.

[0100] In addition, the system may include solvents, electrolytes, brightness modifiers, complexing agents, reducing agents, catalysts, or combinations thereof that are commonly used in electroless or electroplating.

[0101] For example, the plating solution used in electroless plating may contain sulfuric acid (H2SO4), hydrogen peroxide (H2O2), hydrochloric acid (HCl), hydrofluoric acid (HF), or a combination thereof for etching; palladium chloride (PdCl2) as a catalyst; and hydrochloric acid (HCl), nitric acid (HNO3), or a combination thereof as an activator.

[0102] Furthermore, the plating solution used in the electroless plating method may contain, as a complexing agent, tetrasodium EDTA (Na4EDTA), citric acid (C6H8O7), citric acid (C6H8O7), glycine, or a combination thereof, and as a reducing agent, formaldehyde (HCHO), glucose, sodium hypophosphinate, hydrazine, sodium sulfite, boron compounds, or a combination thereof.

[0103] For example, the plating solution used in electroplating may contain boric acid (H3BO3), saccharin, or a combination thereof.

[0104] In one embodiment of the present application, the third step may include a step of electroless plating.

[0105] In one embodiment of the present application, the third step may include an electroplating step after the electroless plating step.

[0106] For example, one or more electroless plating steps can be performed with copper, or one or more electroless plating steps with copper followed by one or more electroplating steps with nickel, or the cycle of electroless plating with copper followed by electroplating with nickel can be repeated one or more times.

[0107] In one embodiment of the present application, the composite material may include the nonwoven fabric.

[0108] The composite material may contain a resin, which may include epoxy resin, phenolic resin, polyester resin, silicone resin, polyethylene resin, polypropylene resin, polystyrene resin, polycarbonate resin, polyamide resin, polyurethane resin, or a combination thereof.

[0109] The composite material can be manufactured by first producing a prepreg from the nonwoven fabric using a hot-melt method, a solution-impregnation method, or a combination thereof, and then laminating one or more of the prepregs.

[0110] Furthermore, after laminating the prepregs, the process may additionally include molding, cooling, and delamination steps. [Examples]

[0111] The operation and effects of the invention will be explained in more detail below through specific embodiments of the invention. However, these embodiments are presented merely as examples of the invention and do not define the scope of the invention's rights.

[0112] Manufacturing Example 1 Using 50mm carbon fiber, the basis weight is 80g / m². 2 The wet-laid nonwoven fabric was manufactured as follows: Below, weight percentages are based on a total content of 2,500g.

[0113] A pre-wetting solution was prepared by mixing 0.15% by weight of 50mm carbon fiber (Zolteck) and 0.15% by weight of a nonionic surfactant-based wetting agent in a solvent (water, 492.5g), and then applying a pulper to perform a pre-wetting step at approximately 1,000 rpm.

[0114] Subsequently, 0.6% by weight of an acrylic dispersant (CDS-3000P, Hansol) was dissolved in a solvent (water, approximately 1977.5 g). Then, approximately 500 g of the pre-wetting solution was added, and the mixture was stirred at a low speed of approximately 250 rpm to 350 rpm using an impeller designed to minimize vortex formation, in order to produce a carbon fiber dispersion.

[0115] The wet nonwoven fabric manufacturing solution produced is 25 x 25 cm 2 Paper is made using a hand-operated papermaking machine, then dried in a 120°C hot air drying oven for approximately 30 minutes. After drying, the basis weight is 80 g / m². 2 We manufactured a carbon fiber wet-laid nonwoven fabric.

[0116] The manufactured carbon fiber wet-woven nonwoven fabric was observed using a scanning electron microscope (SEM) and is shown in Figure 1.

[0117] Manufacturing Example 2 The manufacturing process was the same as in Manufacturing Example 1, except that carbon fibers with a length of 6 mm were used.

[0118] Manufacturing Example 3 The manufacturing process was the same as in Manufacturing Example 1, except that 12 mm long carbon fibers were used.

[0119] Example 1 Nickel electroplating was performed on the wet nonwoven fabric produced according to Production Example 1 as follows.

[0120] 55℃, pH4.0, current density 3.5A / dm 2 Nickel electroplating was performed for 10 minutes under the specified conditions, and the composition of the plating bath is shown in Table 1 below.

[0121] [Table 1]

[0122] After nickel electroplating, the parts were washed with distilled water and then dried at 100°C for 10 minutes.

[0123] Example 2 The wet nonwoven fabric produced according to Production Example 1 was subjected to electroless plating with copper, followed by electroplating with nickel, as follows.

[0124] The wet nonwoven fabric produced according to Production Example 1 was washed with distilled water for 1 minute at room temperature, then treated with 30 g / L NaOH at 50°C for 5 minutes, and then washed with distilled water at room temperature for 1 minute. Subsequently, the following pre-plating treatment steps were performed at room temperature: (etching step)-(washing)-(catalysis step)-(washing)-(activation step)-(washing). The compositions of the solutions used in the above pre-treatment steps are shown in Table 2 below.

[0125] [Table 2]

[0126] During this process, the etching step was performed for 5 minutes, the catalysis step for 3 minutes, the activation step for 1 minute, and the washing step for 1 minute each.

[0127] The pre-treated nonwoven fabric was subjected to electroless copper plating at 30°C and pH 12 for 30 minutes. The composition of the plating bath is shown in Table 3 below. Sodium hydroxide was added to adjust the acidity of the plating bath to pH 12.

[0128] [Table 3]

[0129] After electroless plating with copper, electroplating with nickel was performed as an additional step, and the nickel electroplating was carried out in the same manner as in Example 1.

[0130] Comparative Example 1 The wet nonwoven fabric produced according to Production Example 2 was electroplated with nickel using the same method as in Example 1.

[0131] Comparative Example 2 The wet nonwoven fabric produced according to Production Example 2 was subjected to electroless plating with copper in the same manner as in Example 2, followed by electroplating with nickel.

[0132] Comparative Example 3 The wet nonwoven fabric produced according to Production Example 3 was electroplated with nickel using the same method as in Example 1.

[0133] Comparative Example 4 The wet nonwoven fabric produced according to Production Example 3 was subjected to electroless plating with copper in the same manner as in Example 2, followed by electroplating with nickel.

[0134] Evaluation Example 1 For the examples and comparative examples, the presence or absence of plating and the weight and basis weight before and after plating were measured to confirm the weight increase rate of the nonwoven fabric.

[0135] Examples 1 and 2 were observed using a scanning electron microscope (SEM) and are shown in Figures 2(a) and 2(b), respectively. From these figures, it was confirmed that plating was formed on the carbon fibers.

[0136] On the other hand, in Comparative Examples 1-4, the fiber length was insufficient, and when plating was attempted, it was confirmed that the fibers were defibrated, making plating impossible.

[0137] Manufacturing example 1 is 80g / m².2 5g, 25 x 25cm, depending on the basis weight. 2 The weights of Example 1 and Example 2, which were prepared and plated, were 7.47 g and 7.65 g, respectively.

[0138] The basis weight after plating was determined by converting the weight per unit area (1m x 1m) for both Examples 1 and 2. The result was that the basis weight after plating was 119.5g / m² for both. 2 and 122.4 g / m 2 It was confirmed that this was the case.

[0139] The method used to convert the weight increase rate of the nonwoven fabrics in Example 1 and Example 2 to 100% was given by Equation 1 below, and the results are shown in Table 4. <Expression 1> Weight increase rate of nonwoven fabric [%] = [(Weight of nonwoven fabric after plating - Weight of nonwoven fabric before plating) / Weight of nonwoven fabric before plating] × 100

[0140] [Table 4]

[0141] Evaluation Example 2 For the manufacturing examples and implementations, the electromagnetic shielding capability was confirmed at 200 frequencies from 30 MHz to 1.5 GHz based on ASTM-D4935, and the average values ​​are shown in Table 5 below. In the comparative example, the nonwoven fabric was defibrated, making it impossible to confirm its electromagnetic shielding capability.

[0142] [Table 5]

[0143] Compared to manufacturing examples 1-3, plated examples 1 and 2 showed superior electromagnetic shielding, and in particular, example 2, which underwent nickel electroplating after copper electroless plating, was confirmed to show the best electromagnetic shielding.

[0144] Evaluation Example 3 The tensile strength of the manufacturing examples and embodiments was confirmed according to KS K ISO 9073-3, and is shown in Table 6 below. In the comparative example, the nonwoven fabric was defibrated, making it impossible to confirm its tensile strength.

[0145] [Table 6]

[0146] Compared to manufacturing examples 1-3, plated examples 1 and 2 showed superior tensile strength, and in particular, example 2, which underwent nickel electroplating after copper electroless plating, was confirmed to show the best tensile strength.

[0147] The above description of the present invention is illustrative, and a person with ordinary skill in the art to which the present invention pertains will understand that it can be easily modified into other specific forms without altering the technical idea or essential features of the present invention. Therefore, the embodiments described above should be understood to be illustrative and not limiting in all respects.

[0148] The scope of the present invention is defined by the claims set forth below rather than by the detailed description above, and all modifications or alterations derived from the meaning and scope of the claims and the concept of equivalents thereof should be interpreted as being included within the scope of the present invention.

Claims

1. Contains metal-plated carbon fiber, The aforementioned metals include nickel (Ni), copper (Cu), cobalt (Co), zinc (Zn), gold (Au), silver (Ag), chromium (Cr), tin (Sn), palladium (Pd), rhodium (Rh), iron (Fe), or combinations thereof. Nonwoven fabric.

2. The aforementioned plating is performed by electroless plating, electroplating, or a combination thereof. The nonwoven fabric according to claim 1.

3. The weight increase rate of the nonwoven fabric after plating, according to formula 1 below, is 10% or more. The nonwoven fabric according to claim 1. <Formula 1> Weight increase rate of nonwoven fabric [%] = [(Weight of nonwoven fabric after plating - Weight of nonwoven fabric before plating) / Weight of nonwoven fabric before plating] × 100

4. The carbon fibers include pitch-based, PAN-based (poly acrylic nitrogen), rayon-based, or combinations thereof. The nonwoven fabric according to claim 1.

5. The carbon fiber includes recycled carbon fiber. The nonwoven fabric according to claim 1.

6. The average length of the carbon fibers is 20 mm or more. The nonwoven fabric according to claim 1.

7. The electromagnetic shielding measured according to ASTM-D4935 is 30 dB or higher. The nonwoven fabric according to claim 1.

8. The tensile strength measured according to KS K ISO 9073-3 is 5 MPa or more. The nonwoven fabric according to claim 1.

9. The first step involves adding carbon fibers to a solvent to produce a carbon fiber dispersion, A second step of producing a wet nonwoven fabric, comprising the step of drying the carbon fiber dispersion, The process includes a third step of immersing the manufactured wet nonwoven fabric in a plating solution for plating, A method for manufacturing nonwoven fabrics.

10. The average length of the carbon fibers is 20 mm or more. A method for producing a nonwoven fabric according to claim 9.

11. The aforementioned plating solution includes nickel (Ni), copper (Cu), cobalt (Co), zinc (Zn), gold (Au), silver (Ag), chromium (Cr), tin (Sn), palladium (Pd), rhodium (Rh), iron (Fe), or a combination thereof. A method for producing a nonwoven fabric according to claim 9.

12. The plating method in the third step is electroless plating, electroplating, or a combination thereof. A method for producing a nonwoven fabric according to claim 9.

13. The third step includes the step of electroless plating with copper. A method for producing a nonwoven fabric according to claim 9.

14. The third step includes a step of electroless plating with copper followed by a step of electroplating with nickel. A method for producing a nonwoven fabric according to claim 9.

15. A nonwoven fabric comprising any one of claims 1 to 8, Composite material.

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