Vibration-damping steel sheet and manufacturing method therefor

Abstract

The present invention relates to a vibration-damping steel sheet having excellent vibration-damping performance even at room temperature and a method for manufacturing a vibration-damping steel sheet having improved productivity.

Description

Vibration-damping steel plate and method for manufacturing the same

[0001] The present invention relates to a vibration damping steel plate and a method for manufacturing the same.

[0002] Damping steel plates can be used in a wide variety of applications to reduce noise, such as in drums or base plates of home appliances that generate a lot of noise, such as washing machines and dryers.

[0003] Damping steel plates can be manufactured by bonding two steel plates using a thermoplastic resin. Typically, the thermoplastic resin used is a solid plastic such as polyethylene, polypropylene, or polyamide, or a hot-melt resin such as ethylene vinyl acetate (EVA).

[0004] Thermoplastic resins undergo plastic deformation when heated, making them easy to shape, but they harden when cooled. This has led to the problem that conventional vibration damping steel plates have difficulty absorbing vibrations occurring at room temperature.

[0005] Meanwhile, the manufacturing of conventional damping steel plates essentially involves a thermal bonding process, where high-temperature heat is applied to the thermoplastic resin. This process requires a long time for the thermoplastic resin to melt, and the damping steel plates must then be cooled to room temperature after being pressed, resulting in significant time required for commercialization.

[0006] In this way, research is needed to improve the damping performance and productivity of damping performance.

[0007] (Patent Document 1) Chinese Utility Model Publication No. 211689981.

[0008] One aspect of the present invention relates to a vibration damping steel plate having improved vibration damping performance under room temperature conditions.

[0009] Another aspect of the present invention relates to a method for manufacturing a vibration damping steel plate having improved productivity.

[0010] The objectives of the present invention are not limited to the above-described content. Those skilled in the art will have no difficulty understanding the additional objectives of the present invention from the overall description of the present invention.

[0011] According to exemplary embodiments of the present invention, a damping steel plate is provided. The damping steel plate comprises: a plurality of steel plates; and a damping layer having a thickness of 10 to 250 μm interposed between the steel plates, wherein the damping layer is formed by drying a damping forming solution including a first resin having a glass transition temperature of -80 to -20°C and a second resin having a glass transition temperature of 5 to 100°C.

[0012] The above first resin may be an alkyl acrylate resin.

[0013] The above first resin may be one or two or more selected from 2-ethylhexyl acrylate, butylacrylate, and ethyl acrylate.

[0014] The above damping forming solution may include, in weight %, 75 to 90% of the first resin and 10 to 25% of the second resin.

[0015] The second resin may be at least one of methyl acrylate, methyl methacrylate, and polymers thereof.

[0016] The above damping forming solution may contain, based on 100 parts by weight of the total of the first resin and the second resin, 5 to 10 parts by weight of an adhesion promoter, 0.1 to 2 parts by weight of a curing agent, and 10 to 20 parts by weight of an adhesive agent.

[0017] The above damping forming solution may contain 90 to 150 parts by weight of an organic solvent for a total of 100 parts by weight of the first resin, the second resin, the adhesion promoter, the curing agent, and the tackifier.

[0018] The weight average molecular weight of the above damping layer may be in the range of 700,000 to 1,100,000.

[0019] The loss coefficient of the above vibration damping steel plate may be 0.01 or more.

[0020] According to other exemplary embodiments of the present invention, a method for manufacturing a damping steel plate is provided. The method for manufacturing the damping steel plate comprises the steps of: providing a damping layer on the surface of a first steel plate using a damping forming solution; providing a second steel plate on the surface of the damping layer; and pressing the first or second steel plate, wherein the pressing is performed under room temperature conditions.

[0021] The step of providing the above damping layer may include: applying the damping forming solution to a release paper; drying the damping forming solution at a temperature range of 110 to 150°C to obtain a damping layer; providing the damping layer on the surface of the first steel plate; and removing the release paper.

[0022] The steel plate according to exemplary embodiments can exhibit excellent vibration damping performance even at room temperature conditions by including a polymer adhesive having adhesive strength at room temperature conditions.

[0023] The method for manufacturing a damping steel plate according to other embodiments allows for bonding damping steel plates at room temperature, thereby eliminating the need for a conventional thermal bonding process. This simplifies the damping steel plate manufacturing process and reduces manufacturing costs.

[0024] The various advantageous and beneficial effects of the present invention are not limited to the above-described contents, and will be more easily understood in the course of explaining specific embodiments of the present invention.

[0025] Figure 1 is a schematic diagram for explaining a vibration damping steel plate according to one embodiment of the present invention.

[0026] Figure 2 is a diagram showing a modal evaluation method for measuring loss coefficient.

[0027] Figure 3 is a drawing showing the specimen specifications of the T-peel test method.

[0028] The present invention will be described in detail below. The terms used herein are intended to describe the invention and are not intended to limit it. Furthermore, the singular forms used herein also include the plural forms, unless the relevant definition clearly indicates a contrary meaning.

[0029] The meaning of "comprising" as used in the specification is to specify a configuration and not to exclude the presence or addition of other configurations.

[0030] Unless otherwise defined, all terms, including technical and scientific terms, used herein have the same meaning as commonly understood by a person of ordinary skill in the art to which this invention pertains. Terms defined in the dictionary are to be interpreted to have meanings consistent with the relevant technical literature and the present disclosure.

[0031] Fig. 1 is a drawing for explaining a vibration damping steel plate (10) according to exemplary embodiments.

[0032] According to exemplary embodiments, the damping plate (10) includes a plurality of steel plates (1) and a damping layer (2) interposed between the steel plates.

[0033] The plurality of steel plates (1) may be two or more. Each of the plurality of steel plates (1) may be a steel plate of the same type or different types.

[0034] Each of the plurality of steel plates (1) may be one of a cold-rolled steel plate, a hot-rolled steel plate, a galvanized steel plate, a zinc-plated steel plate, a stainless steel plate, and an aluminum plate.

[0035] A damping layer (2) is interposed between a plurality of steel plates (1).

[0036] According to exemplary embodiments, the thickness of the damping layer (2) may be in the range of 10 μm to 250 μm. More specifically, the thickness of the damping layer (2) may be in the range of 10 μm to 200 μm. As a non-limiting example, the thickness of the damping layer (2) may be in the range of 60 μm to 200 μm.

[0037] If the thickness of the damping layer (2) is less than 10 ㎛, the adhesive strength between the damping layer (2) and the steel plate may be insufficient, causing the damping steel plate (10) to easily disintegrate. In addition, the two steel plates may be excessively close to each other, resulting in poor damping performance of the damping steel plate (10). If the thickness of the damping layer (2) exceeds 250 ㎛, the manufacturing cost of the damping steel plate may increase excessively.

[0038] The damping layer (2) can be provided by drying a damping forming solution containing a polymer resin. The viscosity of the damping forming solution can range from 1,000 to 7,000 cps. As a result, the damping layer can have adhesive performance at room temperature. In the present invention, the viscosity of the damping forming solution refers to the viscosity measured at room temperature (approximately 25°C).

[0039] If the viscosity of the damping solution is less than 1,000 cps, sufficient bonding of the damping steel plates may not be achieved. This necessitates additional processes to increase the thickness of the damping layer, potentially increasing processing costs. However, if the viscosity of the damping solution exceeds 7,000 cps, the damping layer becomes excessively thick, making handling difficult during manufacturing.

[0040] According to exemplary embodiments, the damping layer (2) may be formed by drying a damping forming solution containing a polymer resin.

[0041] The weight average molecular weight of the damping forming solution may range from 700,000 to 1,100,000. If the weight average molecular weight is less than 700,000, the cohesive properties of the damping forming solution may be poor, resulting in poor durability of the damping layer. In addition, the adhesive strength of the damping layer may be insufficient, causing it to easily peel off from the steel plate. If the weight average molecular weight exceeds 1,100,000, the damping forming solution may gel or its viscosity may increase, making coating difficult.

[0042] Weight average molecular weight is the molecular weight that considers the weight of a polymer. Weight average molecular weight can be calculated using the following equation 1.

[0043] [Relationship 1]

[0044] Mw = Σ Mi 2 *Ni / Σ MiNi

[0045] Mw: Weight average molecular weight

[0046] Mi: molecular weight

[0047] Ni: number of moles of corresponding molecular weight

[0048] The damping forming solution may include a first resin, a second resin, an adhesion promoter, a curing agent, a tackifier, and an organic solvent.

[0049] The material composition of the damping forming solution, excluding the organic solvent, may be substantially identical to that of the damping layer. This is because the organic solvent volatilizes during the manufacturing process as it forms the damping layer. However, trace amounts of the organic solvent may remain and be incorporated into the damping layer.

[0050] The first resin may be the main resin of the damping layer.

[0051] The first resin may be present in an amount of 75 to 90 wt% based on the total weight of the damping forming solution. If the content of the first resin is less than 75%, the initial adhesive strength of the damping layer may be reduced. In addition, the viscosity flow region of the damping layer may be narrowed, resulting in insufficient viscosity at room temperature. If the content of the first resin exceeds 90%, the cohesiveness of the damping forming solution may be weakened, resulting in insufficient adhesive strength and adhesion of the damping layer.

[0052] The glass transition temperature of the first resin may be in the temperature range of -80 to -20°C. More specifically, the glass transition temperature of the first resin may be in the temperature range of -80 to -40°C. If the glass transition temperature of the first resin is lower than -80°C, the cohesiveness of the damping forming solution may be weakened. In addition, if the glass transition temperature of the first resin exceeds -20°C, the initial adhesive strength of the damping layer may be degraded. Furthermore, the damping performance of the damping steel plate may be degraded.

[0053] In this way, by including a first resin having a glass transition temperature within a certain range within an appropriate range, the cohesiveness of the damping forming solution can be improved, and further, the adhesiveness of the damping layer can be improved.

[0054] The first resin may include an alkyl acrylate resin. The alkyl acrylate resin has excellent weather resistance and oil resistance, and has excellent adhesiveness due to its polymerizability that allows it to be easily synthesized into a copolymer. As a non-limiting example, the first resin may include one or more selected from 2-ethylhexyl acrylate, butylacrylate, and ethyl acrylate.

[0055] The second resin may be present in an amount of 10 to 25% by weight relative to the total weight of the damping forming solution. If the content of the second resin is less than 10%, the cohesiveness of the damping forming solution may be weakened at room temperature. If the content of the second resin exceeds 25%, the initial adhesive strength of the damping layer may be reduced.

[0056] The glass transition temperature of the second resin may range from 5 to 100°C. If the glass transition temperature of the second resin is lower than 5°C, the cohesive properties of the damping forming solution may deteriorate at room temperature. In this case, the adhesive strength of the damping layer may decrease at room temperature. If the glass transition temperature of the second resin exceeds 100°C, the hardness of the damping layer may increase excessively at room temperature. In this case, the damping properties of the damping layer may deteriorate.

[0057] In this way, by controlling the content of the second resin having a glass transition temperature within the above-described range, the adhesive strength and viscosity of the damping layer at room temperature can be improved. Consequently, the damping performance of the damping steel plate at room temperature can be improved.

[0058] As a non-limiting example, the second resin may be any one of methyl acrylate, methyl methacrylate, and polymers thereof. The methyl acrylate-based resin may contribute to improving the cohesiveness of the first resin, thereby improving the adhesiveness of the damping forming solution.

[0059] The adhesion promoter may be included in an amount of 5 to 10 parts by weight per 100 parts by weight of the first and second resins. If the content of the adhesion promoter is less than 5 parts by weight, the adhesion between the damping layer and the steel plates may be degraded. If the content of the adhesion promoter exceeds 10 parts by weight, the viscosity of the damping forming solution may be difficult to control. In this case, the processability of the damping forming solution may be degraded.

[0060] The adhesion promoter may include a resin containing a carboxyl group or a hydroxyl group. As a non-limiting example, the adhesion promoter may include one or more selected from acrylic acid, methacrylic acid, hydroxyethyl methacrylate, and hydroxymethyl methacrylate.

[0061] The curing agent may be included in an amount of 0.1 to 2 parts by weight per 100 parts by weight of the first resin and the second resin. The curing agent can enhance the cohesiveness of the damping forming solution while maintaining the viscosity. Therefore, the curing agent may be included in an amount of 0.1 part by weight or more. However, if the content of the curing agent exceeds 2 parts by weight, the cohesiveness of the damping forming solution may increase excessively, preventing the damping forming solution from being coated uniformly.

[0062] The curing agent may include one of a metal chelate curing agent and an epoxy curing agent. A non-limiting example of the metal chelate curing agent may include aluminum acetylacetonate. A non-limiting example of the epoxy curing agent may include N,N,N,N-tetraglycidyl-m-xylene diamine.

[0063] The tackifier may be included in an amount of 10 to 20 parts by weight based on 100 parts by weight of the total of the first and second resins. The addition of the tackifier can further enhance the adhesive strength of the damping layer. For this purpose, the tackifier may be included in an amount of 10 parts by weight or more. However, if the content of the tackifier exceeds 20 parts by weight, the cohesiveness of the damping forming solution may increase excessively, making coating of the damping forming solution difficult. Furthermore, the manufacturing cost of the damping steel plate may increase.

[0064] As a non-limiting example, the tackifier may include one or more of benzoic acrylate and cyclohexylacrylate.

[0065] The organic solvent may be included in an amount of 90 to 150 parts by weight per 100 parts by weight of the total of the first resin, the second resin, the adhesion promoter, the curing agent, and the tackifier. More specifically, the organic solvent may be included in an amount substantially equal to the total weight of all resin types.

[0066] When the content of the organic solvent is 90 parts by weight, the workability of the damping forming solution may be poor. When the content of the organic solvent exceeds 150 parts by weight, it is difficult to control the thickness of the damping layer.

[0067] As a non-limiting example, the organic solvent may be one of toluene, acetone, isopropyl alcohol, n-hexane, and mixtures thereof.

[0068] A damping steel plate including a damping layer formed using the above-described steel plates and a damping forming solution can have high damping properties even at room temperature.

[0069] The loss factor of the damping steel plate according to exemplary embodiments may be 0.01 or greater. The impact noise generated when measuring the impact noise by a spring hammer impact test of the damping steel plate may be less than 73 dB.

[0070] Hereinafter, a method for manufacturing a damping steel plate will be described. According to exemplary embodiments, the method may include the steps of providing a second steel plate on the surface of a damping layer, and pressing the first steel plate or the second steel plate.

[0071] According to exemplary embodiments, a damping layer can be provided on the surface of the first steel plate using a damping forming solution.

[0072] As an example, a damping forming solution can be coated on the surface of a first steel plate and then dried to form a damping layer.

[0073] As another example, a damping forming solution may be applied to a release paper and then dried to form a damping layer. In this case, a step of removing the release paper may be further included after the damping layer formed on the release paper is provided on the surface of the first steel plate.

[0074] Drying of the damping forming solution can be accomplished at a temperature range of 110 to 150°C. This allows the organic solvent in the damping forming solution to evaporate, and the resin species to harden through a crosslinking reaction. This allows for the production of a damping layer with excellent adhesion and viscosity even at room temperature.

[0075] According to exemplary embodiments, a second steel plate may be provided on the surface of the damping layer. The second steel plate may be substantially the same steel plate as the first steel plate. The second steel plate may be a different steel plate from the first steel plate.

[0076] According to exemplary embodiments, the first steel plate or the second steel plate can be pressed. As a result, the first steel plate and the second steel plate can be fixed to each other by the damping layer. That is, a vibration-damping steel plate according to exemplary embodiments can be obtained through this step.

[0077] As a non-limiting example, the pressing of the first steel plate or the second steel plate may be performed using a pressing press. The pressure of the pressing press may range from about 10 MPa to about 30 MPa. If the pressure of the pressing press is less than 10 MPa, the damping layer and the first and second steel plates may not sufficiently adhere to each other. In this case, the durability of the damping steel plate may be inferior. If the pressure of the pressing press exceeds 30 MPa, the damping layer may be damaged.

[0078] According to exemplary embodiments, the pressing of the first and second steel plates is performed at room temperature. Thus, high-temperature heat treatment for bonding the first and second steel plates can be omitted. Consequently, cooling processes, such as air cooling, after the high-temperature heat treatment can also be omitted. Consequently, the number of steps in the vibration-damping steel plate manufacturing process can be reduced, thereby reducing process costs and preventing equipment loads caused by high-temperature heat treatment.

[0079] The above-described steps can be repeated to additionally laminate a damping layer and steel plate on the second steel plate.

[0080] Hereinafter, the present invention will be described in more detail through examples. However, it should be noted that the following examples are intended only to illustrate and concretize the present invention and are not intended to limit the scope of the invention. This is because the scope of the invention is determined by the matters set forth in the patent claims and matters reasonably inferred therefrom.

[0081] Example 1

[0082] A damping forming solution was prepared containing 80 wt% of 2-ethylhexylacrylate as a first resin, 20 wt% of methyl acrylate as a second resin, 4 parts by weight of acrylic acid as an adhesion promoter, and 0.3 parts by weight of N,N,N,N-tetraglycidyl-m-xylene diamine as a curing agent. The glass transition temperature of 2-ethylhexylacrylate is about -70°C. The glass transition temperature of methyl acrylate is about 8°C.

[0083] The above damping forming solution was coated on a release paper and then dried at a temperature of approximately 110°C to provide a damping layer with a thickness of 10 μm on the release paper. The viscosity of the damping layer at room temperature (approximately 25°C) is approximately 6500 cps.

[0084] The damping layer provided on the release paper was attached to a galvanized steel plate measuring 200 x 300 mm. The release paper was removed, and another galvanized steel plate of the same size was added to the exposed surface of the damping layer. The galvanized steel plate was pressed at room temperature for approximately 10 seconds at a pressure of approximately 20 MPa to manufacture a vibration-damping steel plate.

[0085] Examples 2 to 8

[0086] A vibration damping steel plate was manufactured in the same manner as in Example 1, except that the thickness of the damping layer was changed as shown in Table 1 below.

[0087] Comparative Example 1

[0088] Galvanized steel sheet of 200х300 mm size was prepared.

[0089] Comparative Example 2

[0090] A solution containing a urethane resin (Aekyung Special Paint, PS-SP) was prepared as a damping forming solution. The glass transition temperature of the urethane resin is 80–100°C.

[0091] The above damping forming solution was coated on a galvanized steel plate measuring 200 X 300 mm and then dried at approximately 150°C to provide a damping layer of approximately 30 μm on the galvanized steel plate. The viscosity of the damping layer at room temperature (approximately 25°C) was approximately 5 cps.

[0092] A vibration damping steel plate according to a comparative example was obtained by attaching a galvanized steel plate on a damping layer and then thermally pressing it. Thermal pressing was performed by applying pressure of 20 MPa for 5 minutes at a temperature of approximately 200°C.

[0093] Comparative Example 3

[0094] As a damping layer, a solid film of about 100 μm thickness containing ethylene vinyl acetate (EVA) resin was prepared.

[0095] The above solid film was placed between two galvanized steel sheets and then thermo-compression-bonded to produce a vibration-damping steel sheet. The thermo-compression was performed by pressing at approximately 140°C and a pressure of 20 MPa for 5 minutes.

[0096] The vibration damping performance and impact noise of the vibration damping steel plates prepared according to the examples and comparative examples above were evaluated. Furthermore, the adhesive strength of the prepared examples was evaluated. The evaluation results are presented in Tables 1 and 2 below.

[0097] Damping performance can be measured by the ability of a material to convert vibration energy into heat energy when subjected to vibration, using the loss factor (η). The loss factor (η) is defined by the following relationship 2, where E is the total vibration energy of the material when vibrating, and △E is the energy dissipated by converting it into heat energy during one vibration cycle.

[0098] [Relationship 2]

[0099] η= △E / 2πE (η≤1)

[0100] Here, η represents the vibration loss coefficient.

[0101] The above loss factor and vibration response values ​​were measured using the modal evaluation method of Fig. 2. The modal evaluation method is a type of vibration test that is an impact test using a hammer on a test piece. The loss factor was measured using the vibration characteristics generated after impacting the specimen with a hammer to determine whether vibration and noise were reduced. At this time, the loss factor values ​​in the low-frequency range below 1 KHz and the high-frequency range above 1 KHz were measured, and the averages thereof are shown in Tables 1 and 2. The larger the loss factor value, the better the vibration damping performance can be evaluated.

[0102] Impact noise was evaluated using the impact noise measurement method using a spring hammer impact test.

[0103] The specimen is fixed to the specimen stand, a hammer is dropped on the specimen, and the noise generated from the specimen is captured by a microphone to measure the noise level.

[0104] Adhesion was evaluated using the t-peel evaluation method.

[0105] Figure 3 is a drawing explaining the t-peel evaluation method.

[0106] A specimen is manufactured as illustrated in Fig. 3. The specimen size is 100 x 25 mm. The maximum load value is evaluated as the adhesive strength of the damping layer when peeling at a peeling speed of 50 mm / min using a tensile tester. An adhesive strength of 1 kgf / 25 mm or higher is considered average, and 3 kgf / 25 mm or higher is considered excellent.

[0107] ClassificationExample 1Example 2Example 3Example 4Example 5Example 6Example 7Example 8Damping layer thickness (㎛) 10203060100150200250Loss coefficient0.0100.0570.0830.1630.1620.1670.1620.1Impact noise (dB) 7271716970686969Adhesive strength (kgf / 25mm) 1.01.73.04.54.84.64.64.5

[0108] Classification Comparison Example 1 Comparison Example 2 Comparison Example 3 Adhesion Method GI Material Sole Hot Melt Coating (Urethane) Hot Melt Film (EVA) Loss Factor 0.002 0.006 0.005 Impact Noise (dB) 867371

[0109] Referring to Tables 1 and 2, the damping steel plates according to the exemplary embodiments exhibit excellent damping performance and generate minimal impact noise. Furthermore, since they do not completely solidify even at room temperature, their adhesive strength is above average, allowing the damping steel plates to be produced through a simple pressing process.

[0110] Since Comparative Example 1 does not include a damping layer, the impact noise level (dB) was measured to be higher than that of the vibration damping steel plate according to the exemplary embodiments of the present invention. In addition, Comparative Example 1 also measured a lower loss coefficient, confirming that its vibration damping performance is inferior.

[0111] In this way, by comparing the vibration damping steel plates according to Comparative Example 1 and exemplary embodiments of the present invention, it was confirmed that vibration damping performance and impact performance can be improved by including a damping layer between at least two steel plates.

[0112] Comparative Example 2 formed a damping layer using a solution containing only one type of resin (urethane-based resin). Consequently, room-temperature adhesive strength and tackiness were poor, necessitating thermal compression in a high-temperature environment to provide a damping steel plate. Consequently, although the impact noise of the damping steel plate in Comparative Example 2 was reduced by including the damping layer, its damping performance was only about 3 / 5 to 3 / 100 of that of the damping steel plates according to exemplary embodiments of the present invention.

[0113] Comparative Example 3 uses a solid film, not a liquid. Therefore, as in Comparative Example 2, thermal compression in a high-temperature environment was essential to provide a damping steel plate. Consequently, the damping performance, as represented by the loss factor of Comparative Example 3, was inferior.

[0114] Although the present invention has been described with reference to the above embodiments, it will be understood by those skilled in the art that various modifications and changes can be made to the present invention without departing from the spirit and scope of the present invention as set forth in the claims below.

[0115] (Explanation of symbols)

[0116] 10: Damping steel plate

[0117] 1: Steel plate

[0118] 2: Damping layer

Claims

1. Multiple steel plates; and It includes a damping layer with a thickness of 10 to 250㎛ interposed between the above steel plates, The above damping layer is, A damping steel plate formed by drying a damping forming solution containing a first resin having a glass transition temperature of -80 to -20°C and a second resin having a glass transition temperature of 5 to 100°C.

2. In paragraph 1, The above first resin is a vibration-damping steel plate which is an alkyl acrylate resin.

3. In paragraph 1, A vibration-damping steel plate wherein the first resin is one or more selected from 2-ethylhexyl acrylate, butylacrylate, and ethyl acrylate.

4. In paragraph 1, A damping steel plate comprising, in weight %, a first resin: 75 to 90% and a second resin: 10 to 25%.

5. In paragraph 1, A vibration-damping steel plate wherein the second resin is at least one of methyl acrylate, methyl methacrylate, and polymers thereof.

6. In paragraph 1, The above damping forming solution is a vibration-damping steel plate containing, with respect to 100 parts by weight of the total of the first resin and the second resin, 5 to 10 parts by weight of an adhesion promoter, 0.1 to 2 parts by weight of a hardener, and 10 to 20 parts by weight of a tackifier.

7. In paragraph 6, The above damping forming solution is a vibration-damping steel plate containing 90 to 150 parts by weight of an organic solvent per 100 parts by weight of the total of the first resin, the second resin, the adhesion promoter, the curing agent, and the tackifier.

8. In paragraph 1, A damping steel plate having a weight average molecular weight of the damping layer in the range of 700,000 to 1,100,000.

9. In paragraph 1, A vibration damping steel plate having a loss coefficient of 0.01 or more.

10. A step of providing a damping layer on the surface of the first steel plate using a damping forming solution; a step of providing a second steel plate on the surface of the damping layer; and Comprising a step of pressurizing the first steel plate or the second steel plate, A method for manufacturing a vibration-damping steel plate in which the above pressurization is performed under room temperature conditions.

11. In paragraph 10, The step of providing the above damping layer is: A step of applying the above damping forming solution to a release paper; A step of drying the above damping forming solution at a temperature range of 110 to 150°C to obtain a damping layer; a step of providing the damping layer on the surface of the first steel plate; and A method for manufacturing a vibration-damping steel plate, comprising the step of removing the above-mentioned release paper.

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