Ceramic paper and its manufacturing method

Abstract

The present invention relates to a ceramic paper and a manufacturing method thereof, and more particularly to a ceramic paper comprising polycrystalline alumina fiber, a binder, a retaining agent, a dispersing agent and a thickening agent, and a manufacturing method thereof.

Description

[Technical Field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 2021-0122160, filed on September 14, 2021, and all contents disclosed in the documents of that Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a ceramic paper and a manufacturing method thereof, and more particularly to a ceramic paper that has excellent heat resistance and moldability, and is thin enough to minimize an increase in volume when mounted in a battery module or a battery pack, and a manufacturing method thereof. [Background technology]

[0003] Most existing flame retardant heat dissipation and insulation products are in the form of non-woven fabrics based on alumino-silicate ceramic fibers.

[0004] This is made into fabrics using the dry-laid method through needle punching or carding, or in the form of lamination or molding, but in addition to lower productivity, it has problems such as difficulty in transportation due to its large volume, air pollution due to fine ceramic dust during use, and harm to the health of workers.

[0005] On the other hand, ceramic paper has been used in parts that require heat resistance and insulation, such as sealing materials for gaskets, filling materials for expansion pads in fireproof insulation walls, protective tubes for molten metal temperature sensors, filling materials for various refractories, and insulating materials for automobile exhaust gas purification devices.

[0006] However, in relation to recent environmental issues, a major shift in energy sources for mobility is underway, and while demand for internal combustion engine vehicles is declining, demand for electric vehicles or fuel cell vehicles (PHEV, BEV, hybrid, hydrogen vehicles) is increasing. However, in the case of electric vehicles based on secondary batteries, fires in charging batteries have not only caused damage to property but also loss of life.

[0007] Therefore, there is an urgent need to develop parts and materials that can prevent battery fires and minimize the spread of flames, so that people can have enough time to escape from the scene in the event of a fire caused by thermal runaway barrier. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Korean Patent Publication No. 2006-0078683 [Patent Document 2] Korean Patent Publication No. 1991-0006187 [Patent Document 3] Korean Patent Publication No. 2015-0066857 [Patent Document 4] Korean Patent Publication No. 2006-0084124 Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention has been developed to solve the above problems, and an object of the present invention is to provide ceramic paper having excellent heat resistance and formability, and a method for producing the same. Another object of the present invention is to provide a ceramic paper that is thin and flexible, and a method for producing the same. [Means for solving the problem]

[0010] In order to solve the above technical problems, the ceramic paper according to the present invention is characterized by comprising polycrystalline alumina fiber, a binder, a retaining agent, a dispersant, and a thickener.

[0011] In addition, in the ceramic paper of the present invention, the binder is made of an organic binder and an inorganic binder, and the retaining agent is made of PAC (polyaluminum chloride) and C-PAM (Cationic-Polyacrylamide).

[0012] Furthermore, in the ceramic paper of the present invention, the polycrystalline alumina fiber has an alumina content of 70% or more, a fiber diameter of 4 μm to 10 μm, an LOI (Loss of Ignition) of 0.1% or less, and a thermal conductivity of 0.44 W / m / K or less at 1,200°C; the organic binder is PVA (Polyvinylalcohol) having a chopped fiber shape, a fineness of 0.3 dtex to 3.0 dtex, a fiber length of 2 mm to 6 mm, and a dissolution temperature in water of 60°C to 80°C; the inorganic binder is silica sol or alumina sol; the dispersant is a PEG (Poly Ethylene Glycol)-based nonionic surfactant; and the thickener is PEO (Polyethylene Oxide).

[0013] Furthermore, the ceramic paper of the present invention is characterized in that the polycrystalline alumina fiber, organic binder, inorganic binder, PAC, C-PAM, dispersant, and thickener are mixed in a weight ratio of 70-95:3-18:3-12:2-6:1-2:1-3:0.2-2.0.

[0014] The ceramic paper of the present invention is characterized in that the polycrystalline alumina fiber, organic binder, inorganic binder, PAC, C-PAM, dispersant, and thickener are mixed in a weight ratio of 73-92:3-17:3-12:2-4:1.2-1.8:1.2-2.7:0.3-1.7.

[0015] In addition, in the ceramic paper of the present invention, the basis weight is 39 g / m 2 ~40g / m 2 When the thickness is 275 μm to 300 μm, the porosity is 6.8 cm 3 / g~7.2cm 3 / g, density 13kg / m 3 ~15kg / m 3 It is characterized in that:

[0016] In addition, the method for manufacturing ceramic paper of the present invention includes the steps of: (a) preparing raw materials; (b) mixing the prepared raw materials to prepare a raw material mixture; (c) stacking the raw material mixture on a mesh belt; (d) dehydrating the raw material mixture stacked on the mesh belt; and (e) drying the raw material mixture, wherein the raw materials include polycrystalline alumina fiber, a binder, a retaining agent, a dispersant, and a thickener.

[0017] In addition, in the method for producing ceramic paper of the present invention, in step (b), 9,900 to 11,000 parts by weight of water as a solvent, 70 to 95 parts by weight of polycrystalline alumina fiber, 3 to 18 parts by weight of an organic binder, 3 to 12 parts by weight of an inorganic binder, 2 to 6 parts by weight of PAC (polyaluminium chloride), 1 to 2 parts by weight of C-PAM (Cationic-Polyacrylamide), 1 to 3 parts by weight of a dispersant, and 0.2 to 2.0 parts by weight of a thickener are mixed in a ratio of 9,900 to 11,000 parts by weight.

[0018] In addition, in the method for manufacturing ceramic paper of the present invention, in step (b), polycrystalline alumina fiber and an organic binder are mixed together, and then an inorganic binder, PAC (polyaluminium chloride), and C-PAM (Cationic-Polyacrylamide) are mixed sequentially. [Effects of the Invention]

[0019] As described above, the ceramic paper and the method for producing the same of the present invention have the advantage of excellent heat resistance because they use crystalline fibers with an alumina content of 70% or more as the main component.

[0020] In addition, the ceramic paper and manufacturing method thereof according to the present invention have the advantage that molding processing is easy and the manufactured paper is thin, thereby minimizing the increase in volume when installed in a battery module or battery pack.

[0021] Furthermore, the ceramic paper and the manufacturing method thereof according to the present invention have excellent density and porosity, and therefore have the advantage of contributing to improved fuel economy through weight reduction when applied to automobile battery modules, etc. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a flowchart illustrating a method for manufacturing ceramic paper according to a preferred embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0023] The present invention will now be described in more detail with reference to preferred embodiments and drawings, which are intended to be sufficient to enable those skilled in the art to easily practice the present invention, and are not intended to limit the technical scope and spirit of the present invention.

[0024] Furthermore, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art to which the present invention pertains. Each commonly used and predefined term should be interpreted as having a meaning consistent with the contextual meaning of the relevant art, and should not be interpreted in an idealized or overly formal sense unless expressly defined in this application.

[0025] The ceramic paper and the method for producing the same according to the present invention will be described in detail below.

[0026] First, the ceramic paper of the present invention comprises ceramic fibers, a binder, a retaining agent, a dispersant, and a thickener.

[0027] Ceramic fiber is a general term for artificial inorganic fibers whose main component is alumina silica. Ceramic fiber is classified into amorphous fiber, which has an alumina content of 40% to 60%, and polycrystalline fiber, which has an alumina content of 70% or more. Depending on the synthesis method, ceramic fiber is also classified into alumina fiber and mullite fiber, but these are collectively called alumina fiber.

[0028] The present invention uses crystalline fibers with an alumina content of 70% or more. The fiber diameter is preferably 4 μm to 10 μm, more preferably 5 μm to 7 μm, the loss of ignition (LOI) is 0.1% or less, the shot content (%) that causes deterioration of the product's appearance and quality is 2%, the thermal conductivity (W / m / K) is 0.15 or less at 600°C, 0.31 or less at 1,000°C, and 0.44 or less at 1,200°C, and the heat shrinkage is 1% or less at 1,400°C for 8 hours and 1% or less at 1,600°C for 8 hours.

[0029] The binder is used to improve the mechanical strength of the paper, and it is recommended to use both organic and inorganic binders. This is because it maintains the strength during web formation and prevents paper breakage, and the inorganic binder in particular can improve the binding strength of the ceramic fibers.

[0030] Here, polyvinyl alcohol (PVA) in the form of chopped fiber is preferably used as the organic binder, because in the case of liquid products, the low retention rate during use requires an increased input amount, which results in poor dehydration, increased wastewater load and treatment costs, and deterioration in quality due to spoilage during long-term storage and use. The fineness of such chopped fiber is preferably 0.3 dtex to 3.0 dtex, more preferably 1.0 dtex to 2.0 dtex, the fiber length is preferably 2 mm to 6 mm, more preferably 3 mm to 5 mm, and the dissolution temperature in water is preferably in the range of 60°C to 80°C.

[0031] By using silica sol or alumina sol as an inorganic binder, it is possible to achieve stable bonding strength even at high temperatures.

[0032] Retention aids are added to prevent expensive ceramic fibers from leaking out during the manufacturing process, such as drying and dehydration.

[0033] Specifically, polyaluminum chloride (PAC) and C-PAM (cationic-polyacrylamide) can be used alone or in combination, but when polyaluminum chloride (PAC) and C-PAM (cationic-polyacrylamide) are used together, the amount of C-PAM used can be reduced, thereby saving costs and reducing wastewater load.In addition, since the reduction in the effectiveness of C-PAM due to anionic substances in the system can be suppressed, the retention rate of ceramic fiber can be increased when the two are used in combination rather than when used alone.

[0034] Here, the solid content of the PAC is 10% to 18%, preferably 10%.

[0035] The weight average molecular weight (Mw) of C-PAM is preferably 6 million to 10 million, and more preferably around 10 million.

[0036] As a dispersant for smoothly dispersing ceramic fibers in water and suppressing bundling, it is recommended to use a surfactant, more specifically, a PEG (Poly Ethylene Glycol) based nonionic surfactant containing 7 to 9 moles of ethylene oxide (EO).

[0037] The thickener is added to maximize the dispersion effect and may be polyethylene oxide (PEO). While polyethylene oxide products with a molecular weight of 2 to 3 million are used in conventional papermaking processes, polyethylene oxide with a molecular weight of about 5 million is used in the present invention because ceramic fibers have a high specific gravity and are difficult to retain.

[0038] On the other hand, the above-mentioned raw materials, i.e., ceramic fiber, organic binder, inorganic binder, PAC, C-PAM, dispersant, and thickener, are preferably mixed in a weight ratio of 70-95:3-18:3-12:2-6:1-2:1-3:0.2-2.0 based on 10,000 L of water as a solvent, and more preferably in a weight ratio of 73-92:3-17:3-12:2-4:1.2-1.8:1.2-2.7:0.3-1.7.

[0039] If the ceramic fiber content is outside the above range, the breathability of the nonwoven fabric will be low, making it difficult to commercialize. On the other hand, if the ceramic fiber content is greater than the above range, the dispersibility will be low, resulting in uneven surface texture and the generation of paper dust. Therefore, it is preferable that the ceramic fiber content be within the above range.

[0040] If the content of the organic binder is outside the above range, the wet strength may be low, which may cause paper breakage, or the dispersion and dehydration of the inorganic fibers may be hindered, resulting in reduced productivity and impaired product texture. Therefore, it is preferable that the content of the organic binder is within the above range.

[0041] If the content of the inorganic binder is outside the above range, the heat resistance of the product may be reduced, and the dehydration and density of the product may be reduced. Therefore, it is preferable that the content of the inorganic binder is within the above range.

[0042] If the PAC content is outside the above range, the amount of expensive C-PAM added will increase, which may have a negative impact on cost and dehydration or reduce the effectiveness of C-PAM. Therefore, it is preferable that the PAC content be within the above range.

[0043] If the C-PAM content is outside the above range, the dehydration and formation of the inorganic fibers may be reduced, the dispersion of the inorganic fibers may be hindered, and the bundling phenomenon may increase, resulting in reduced formation and strength. Therefore, it is preferable that the C-PAM content be within the above range.

[0044] If the dispersant content is outside the above range, the quality may deteriorate due to poor dispersion of the inorganic fibers, or the dispersant may contaminate the system and cause poor dispersion of the raw materials. Therefore, it is preferable that the content of the dispersant is within the above range.

[0045] If the content of the thickener deviates from the above range, the viscosity of the solvent in the system will be low, which will inhibit the dispersion of the inorganic fibers, reduce dehydration, and increase the bundling phenomenon of the raw materials, resulting in a decrease in formation quality. Therefore, it is preferable that the content of the thickener be within the above range.

[0046] As a result, when the blending range is satisfied, the physical properties required for ceramic paper, such as thin thickness, high wet tensile strength, high retention, low porosity, and low density, are satisfied.

[0047] Next, a method for producing ceramic paper according to the present invention will be described.

[0048] FIG. 1 is a flowchart illustrating a method for manufacturing ceramic paper according to a preferred embodiment of the present invention.

[0049] As shown in FIG. 1, the ceramic paper of the present invention is produced by the steps of (a) preparing raw materials, (b) mixing the prepared raw materials to prepare a raw material mixture, (c) stacking the raw material mixture on a mesh belt, (d) dehydrating the raw material mixture stacked on the mesh belt, and (e) drying the raw material mixture.

[0050] First, to more specifically describe step (a) of preparing raw materials, step (a) is a step of preparing ceramic fiber, organic binder, inorganic binder, PAC, C-PAM, dispersant, thickener, and solvent.

[0051] Here, the solvent is used to mix the raw materials uniformly, and may be water.

[0052] Specific materials related to the ceramic fiber, organic binder, inorganic binder, PAC, C-PAM, dispersant, and thickener have been described above, and therefore, redundant description thereof will be omitted.

[0053] In step (b) of mixing the prepared raw materials to prepare a raw material mixture, water, a dispersant, and a thickener are first added to a pulper and then stirred for a certain period of time to create an environment in which the ceramic fibers can be individually dispersed without forming bundles.

[0054] Then, the ceramic fiber and organic binder are added at the same time and stirred for 8 to 12 minutes at 700 to 800 rpm. The reason for adding the ceramic fiber and organic binder at the same time is to ensure sufficient stirring time for the ceramic fiber and organic binder, thereby improving the mixing effect, minimizing undispersed raw materials, and shortening on-site work time, thereby increasing productivity.

[0055] Thereafter, the inorganic binder and the retaining agent are additionally supplied, and the mixture is stirred again for 8 to 12 minutes at 700 to 800 rpm to prepare a raw material mixture. At this time, the inorganic binder, PAC, and C-PAM may be added sequentially, i.e., at regular time intervals.

[0056] The reason why the inorganic binder, PAC, and C-PAM are sequentially supplied is to sufficiently disperse each raw material in water, and in particular, to ensure the solubility of the polymer material, thereby sufficiently opening the polymer chains and maximizing reactivity.

[0057] Here, the ceramic fiber, organic binder, inorganic binder, PAC, C-PAM, dispersant, and thickener are preferably mixed in a weight ratio of 70-95:3-18:3-12:2-6:1-2:1-3:0.2-2.0 based on 10,000 L of water as a solvent, and more preferably in a weight ratio of 73-92:3-17:3-12:2-4:1.2-1.8:1.2-2.7:0.3-1.7.

[0058] On the other hand, it is preferable that the water used as the solvent is preheated to 25°C to 45°C. This is because if the water temperature is lower than this range, dispersibility and dehydration properties decrease, while if the water temperature is higher than this range, strain is placed on the raw material mixture and the mesh in stage (c), etc., so it is preferable that the water temperature of the solvent is within this range.

[0059] The step (c) of layering the raw material mixture on the mesh belt is a step of layering the raw material mixture in a slurry state prepared at the above-mentioned blending ratio on the mesh belt. More specifically, the raw material mixture is supplied to the mesh belt moving at a speed of 15 to 30 m per minute, and the supply amount is preferably 9,000 to 10,000 L per minute.

[0060] The step (d) of dehydrating the raw material mixture layered on the mesh belt is a step of dehydrating the raw material mixture layered on the mesh belt to primarily remove water as a solvent.

[0061] At this time, dehydration is carried out by applying a primary vacuum when the raw material mixture is layered on the mesh belt, and then a secondary vacuum is additionally applied to carry out the dehydration process.

[0062] In the primary vacuum dehydration process, four stages of vacuum pressure are applied: stage 1 is 0cmHg~5cmHg, stage 2 is 10cmHg~20cmHg, stage 3 is 30cmHg~40cmHg, and stage 4 is 50cmHg~65cmHg. In addition, this process induces bonds between the fibers through dehydration, resulting in the formation of nonwoven ceramic paper.

[0063] In the second vacuum dehydration process, a vacuum pressure of approximately 18cmHg to 22cmHg is applied to remove residual moisture while further tightening the bonds between the fibers.

[0064] Finally, step (e) of drying the raw material mixture is a step of completely removing residual moisture, and is achieved by passing the raw material mixture sequentially through a hot air dryer and a drum dryer. Specifically, the raw material mixture is first dried in a hot air dryer operated at 100°C to 170°C, preferably 110°C to 130°C, then hot air dried at 135°C to 145°C, then hot air dried at 100°C to 110°C, and finally passed through a drum dryer at 135°C to 145°C.

[0065] Here, if drying is performed at a high temperature in the initial stage, drying occurs too quickly, resulting in shrinkage and paper breakage. On the other hand, if drying is performed at an excessively low temperature, complete binding of the binder fiber is not achieved, and the residual moisture after winding is high, resulting in negative effects such as fuzzing and weakened binding strength in subsequent processes. Therefore, it is preferable to perform drying under the four drying conditions from the first drying to the fourth drying as described above.

[0066] Thereafter, if necessary, a process of slitting the sheet using a slitting device and then storing the sheet may be additionally performed.

[0067] The present invention will be described in more detail below with reference to examples and experimental examples. However, the following examples and experimental examples are merely illustrative of the present invention, and the content of the present invention is not limited to the following examples and experimental examples. [Example]

[0068] Example 1 10,000 L of water, 75 kg of ceramic fiber, 15 kg of organic binder, 10 kg of inorganic binder, 3 kg and 1.5 kg of PAC (polyaluminium chloride) and C-PAM (Cationic-Polyacrylamide) as retaining agents, 2.5 kg of PEG (PolyEthyleneGlycol) as a dispersant, and 1.5 kg of PEO (polyethylene oxide) as a thickener were prepared.

[0069] Here, the ceramic fiber is a polycrystalline alumina fiber with an alumina content of 72%, a fiber diameter of 4 μm to 10 μm, an LOI (Loss of Ignition) of 0.1% or less, a thermal conductivity (W / m / K) of 0.44 or less at 1,200°C, and a thermal shrinkage (%) of less than 1 at 1,600°C for 8 hours.

[0070] The organic binder was in the form of chopped fibers with a fineness of 1.0 dtex to 2.0 dtex, a length of 3 mm to 5 mm, and a melting temperature of 60°C to 80°C, and silica sol with an SiO2 content of 32% was used as the inorganic binder.

[0071] PAC (polyaluminium chloride) has a solid content of 14% and C-PAM (cationic-polyacrylamide) has a molecular weight (Mw) of 10 million. PEG (Polyethylene Glycol) has 7-9 mol of EO (Ethylene Oxide) and a molecular weight (MWCO) of PEO (polyethylene oxide) of 5 million.

[0072] First, water, dispersant, and thickener were added to a pulper and stirred for a certain period of time, then polycrystalline alumina fiber and organic binder were added simultaneously and stirred at 750 rpm for 10 minutes. After that, inorganic binder and retaining agent were added sequentially and mixed again at 750 rpm for 10 minutes to prepare a raw material mixture.

[0073] The prepared raw material mixture was layered on a very fine mesh belt, and the transport speed of the mesh belt was 30 m / min, and the raw material mixture was supplied at a rate of 10,000 L / min.

[0074] At this time, the basis weight is approximately 40 g / m 2 It was adjusted so that

[0075] In addition, at the moment when the raw material mixture was layered on the mesh belt, the first stage of natural dehydration was carried out at a vacuum pressure of 0 cmHg, followed by the second stage of primary dehydration at a vacuum pressure of 10 cmHg, the third stage at a vacuum pressure of 30 cmHg, and the fourth stage at a vacuum pressure of 50 cmHg.

[0076] After the first dehydration, the second dehydration was carried out at a vacuum pressure of 20 cmHg.

[0077] Finally, the raw material mixture was first dried in a hot air dryer operated at 110-130°C, secondly dried at 135-145°C, and thirdly dried at 100-110°C, and then passed through a drum dryer at 135-145°C to remove residual moisture, producing ceramic paper.

[0078] Example 2 Ceramic paper was produced under the same conditions as in Example 1, except that the raw material mixture was changed to 80 kg of polycrystalline alumina fiber, 10 kg of organic binder, 10 kg of inorganic binder, 2.0 kg of PEG (PolyEthyleneGlycol) as a dispersant, and 1.0 kg of PEO (polyethylene oxide) as a thickener.

[0079] Example 3 Ceramic paper was produced under the same conditions as in Example 1, except that the raw material mixture was changed to 90 kg of polycrystalline alumina fiber, 5 kg of organic binder, 5 kg of inorganic binder, 1.5 kg of PEG (PolyEthyleneGlycol) as a dispersant, and 0.5 kg of PEO (polyethylene oxide) as a thickener.

[0080] Example 4 Basis weight: 60g / m 2 Ceramic paper was produced under the same conditions as in Example 1, except that the temperature was adjusted to be

[0081] Example 5 Basis weight: 80g / m 2 Ceramic paper was produced under the same conditions as in Example 1, except that the temperature was adjusted to be

[0082] <Comparative Example> Comparative Example 1 Ceramic paper was produced under the same conditions as in Example 1, except that 75 kg of mineral wool was used in place of polycrystalline alumina fiber in the raw material mixture.

[0083] Here, mineral wool has an average fiber thickness of 7 μm or less and a density of 140 kg / m 3 , thermal conductivity is 0.044W / mk or less, particle content is 4% or less, and hot shrinkage temperature is 550℃.

[0084] Comparative Example 2 Ceramic paper was produced under the same conditions as in Example 1, except that 75 kg of alkaline earth silicate was used in place of polycrystalline alumina fiber in the raw material mixture.

[0085] Here, the alkaline earth silicate has a silica content of 73% or more, a fiber diameter of 3 μm to 12 μm, an LOI of 0.1% or less, and a thermal conductivity of 0.61 W / m / k or less.

[0086] Comparative Example 3 Ceramic paper was produced under the same conditions as in Example 1, except that 75 kg of alumina fiber was used instead of polycrystalline alumina fiber in the raw material mixture.

[0087] Here, the alumina fiber has an alumina content of 70% or more, a fiber diameter of 4 μm to 10 μm, an LOI of 0.1% or less, and a thermal conductivity in the range of 0.44 W / m / K at 1,200°C.

[0088] [Table 1]

[0089] <Experimental Example> The physical properties of the papers produced in Examples 1 to 5 and Comparative Examples 1 to 3 were measured, and the results are shown in Table 2 below.

[0090] The basis weight is 100cm according to the TAPPI T 410 standard. 2 Ten or more samples were collected, and the weights of each were measured. The average value was calculated and corrected (corrected value x 100).

[0091] The thickness of the nonwoven fabric was measured according to the TAPPI T 411 standard with a suitable thickness measuring instrument.

[0092] Wet tensile strength was measured by TAPPI T-456 method.

[0093] Retention was measured by the TAPPI T-261 cm-90 method.

[0094] The formation index is measured by the TAPPI T-272 method, and the lower the formation index value, the better the paper.

[0095] Porosity (Bulk (cm 3 / g) was measured by TAPPA T-536 method.

[0096] Density was measured by the TAPPI T-258 method.

[0097] [Table 2]

[0098] As summarized in Table 2, the 39.5 g / m 2 ~40.0g / m 2 It can be seen that the paper having a basis weight of 100g has excellent overall physical properties such as thickness, wet tensile strength, retention rate and formation index.

[0099] The basis weight is 40.0 g / m 2 (Example 1) to 60.0 g / m 2 (Example 4) and 80.0 g / m 2 When the thickness is increased to (Example 5), it can be seen that the thicknesses are very thin, being only 382 μm and 482 μm, respectively.

[0100] However, in Comparative Examples 1 to 3, the basis weight was 23.1 g / m 2 ~52.5g / m 2 Nevertheless, the thickness is in the range of 1,900 μm to 2,200 μm, so it is very thick, and furthermore, the porosity and density are also much higher than those of the examples of the present invention.

[0101] As such, compared to currently commercially available heat dissipation materials, the paper of the present invention is much thinner, allowing for a reduction in volume. In particular, when the paper is used as a heat dissipation material in battery modules or battery packs such as secondary batteries, its excellent density and porosity can contribute to improved fuel efficiency through weight reduction.

[0102] The present invention has been described above with reference to preferred embodiments. Those skilled in the art will recognize that the present invention can be embodied in various modified forms without departing from its essential characteristics. Therefore, the disclosed embodiments should be considered as illustrative rather than restrictive. The scope of the present invention is defined by the claims, not the above description, and all equivalents thereto should be construed as being within the scope of the present invention.

Claims

1. Contains polycrystalline alumina fiber, binder, retention agent, dispersant and thickener, The binder comprises an organic binder and an inorganic binder, The organic binder is PVA (Polyvinyl alcohol) having a chopped fiber shape, the inorganic binder is silica sol or alumina sol, The fixative comprises PAC (polyaluminum chloride) and C-PAM (Cationic-Polyacrylamide), The dispersant is a PEG (Poly Ethylene Glycol) based nonionic surfactant, The ceramic paper, wherein the thickener is PEO (polyethylene oxide).

2. The polycrystalline alumina fiber has an alumina content of 70% or more, a fiber diameter of 4 μm to 10 μm, an LOI (Loss of Ignition) of 0.1% or less, and a thermal conductivity of 0.44 W / m / K or less at 1,200°C, The ceramic paper according to claim 1, wherein the organic binder has a fineness of 0.3 dtex to 3.0 dtex, a fiber length of 2 mm to 6 mm, and a dissolution temperature in water in the range of 60°C to 80°C.

3. Basis weight: 39 g / m ２ ~40g / m ２ When the thickness is 275 μm to 300 μm, the porosity is 6.8 cm ３ / g ~ 7.2 cm ３ / g, and density 13 kg / m ３ ~15 kg / m ３ The ceramic paper according to claim 1, which satisfies the above.

4. (a) preparing raw materials; (b) mixing the prepared raw materials to prepare a raw material mixture; (c) layering the raw material mixture on a mesh belt; (d) dewatering the raw material mixture layered on the mesh belt; and (e) drying the raw material mixture; The raw materials include polycrystalline alumina fiber, a binder, a retention agent, a dispersant, and a thickener; The binder comprises an organic binder and an inorganic binder, The organic binder is PVA (Polyvinyl alcohol) having a chopped fiber shape, the inorganic binder is silica sol or alumina sol, The fixative comprises PAC (polyaluminum chloride) and C-PAM (Cationic-Polyacrylamide), The dispersant is a PEG (Poly Ethylene Glycol) based nonionic surfactant, A method for producing ceramic paper, wherein the thickener is PEO (polyethylene oxide).

5. 5. The method of claim 4, wherein in step (b), 9,900 to 11,000 parts by weight of water as a solvent, 70 to 95 parts by weight of the polycrystalline alumina fiber, 3 to 18 parts by weight of an organic binder, 3 to 12 parts by weight of an inorganic binder, 2 to 6 parts by weight of PAC (polyaluminum chloride), 1 to 2 parts by weight of C-PAM (Cationic-Polyacrylamide), 1 to 3 parts by weight of the dispersant, and 0.2 to 2.0 parts by weight of the thickener are mixed in a ratio of 9,900 to 11,000 parts by weight.

6. 6. The method of claim 5, wherein in step (b), the polycrystalline alumina fiber and the organic binder are simultaneously mixed, and then the inorganic binder, the PAC (polyaluminum chloride), and the C-PAM (Cationic-Polyacrylamide) are sequentially mixed.

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