Multilayered transparent soundproof panel

Abstract

The present disclosure relates to a multilayered transparent soundproof panel comprising: a core layer containing a polycarbonate (PC) resin, a UV stabilizer, an antioxidant, and a flame retardant; and a surface layer formed on one or both surfaces of the core layer and containing a polymethyl methacrylate (PMMA) resin, a UV stabilizer, a slip agent, an antioxidant, and a chemically resistant antioxidant.

Description

Multilayer transparent soundproofing panel

[0001] The present disclosure relates to a multilayer transparent soundproofing panel.

[0002] Continuing urbanization has led to population density, diversified transportation options, and increased traffic volume. This population density has led to an increase in apartment complexes and the expansion of roads, railways, and airports. Consequently, residents living in apartment complexes, industrial complexes, and near roads, railways, and airports are experiencing significant distress from noise from both their daily lives and transportation.

[0003] Accordingly, a certain level of noise standards are strictly applied when designing apartment complexes, industrial complexes, roads, railways, and airports, and various types of noise barriers are required to meet these noise standards.

[0004] In the past, transparent soundproofing panels made of a single synthetic resin were mainly used, but these soundproofing panels had weak mechanical strength and scratch resistance, so they were easily damaged by external impacts, and scratches frequently occurred on the surface, making it difficult to maintain the soundproofing effect and transparency for a long period of time.

[0005] For example, soundproofing panels made of flat panels have poor soundproofing properties and are prone to yellowing and deterioration when exposed to UV rays or acid rain for extended periods. Furthermore, soundproofing walls made of a single synthetic resin have poor scratch resistance and insufficient surface hardness. Therefore, they are often hard-coated to improve weather resistance, surface hardness, and scratch resistance.

[0006] Therefore, not only does it have excellent soundproofing effects without hard coating, but it also has excellent mechanical strength and weather resistance, and the rate of yellowing or deterioration is low even after long-term use, and there is a need for technological development of soundproofing panels.

[0007] [Prior Art Literature]

[0008] [Patent Document]

[0009] Republic of Korea Patent No. 10-1933129 (announced on December 27, 2018)

[0010] The technical challenge of the present disclosure is to provide a transparent soundproofing panel having excellent soundproofing performance and transparency without hard coating, as well as improved impact resistance, weather resistance, and scratch resistance.

[0011] The present disclosure provides, in one embodiment, a multilayer transparent soundproof panel comprising a core layer including a polycarbonate (hereinafter, PC) resin, an ultraviolet stabilizer, an antioxidant, and a flame retardant, and a surface layer formed on one or both sides of the core layer and including a polymethyl methacrylate (hereinafter, PMMA) resin, an ultraviolet stabilizer, a slip agent, an antioxidant, and a chemically resistant antioxidant.

[0012] Additionally, the surface layer may have unevenness.

[0013] In addition, the core layer may include 0.1 to 1 part by weight of an ultraviolet stabilizer, 0.1 to 1 part by weight of an antioxidant, and 0.1 to 1 part by weight of a flame retardant based on 100 parts by weight of PC resin.

[0014] In addition, the surface layer may contain 0.1 to 15 parts by weight of a UV stabilizer, 0.1 to 1 part by weight of a slip agent, 0.1 to 1 part by weight of an antioxidant, and 0.1 to 1 part by weight of a chemical-resistant antioxidant, based on 100 parts by weight of PMMA resin.

[0015] Additionally, the core layer may have a thickness of 5 to 20 mm, and the surface layer may have a thickness of 100 to 1,000 ㎛.

[0016] Additionally, the PC resin may have a melt index (MI, ASTM D1238, 300°C, 1.2 kg load) of 5 to 12 g / 10 min and a weight average molecular weight of 5,000 to 30,000 g / mol (MW).

[0017] In addition, the PMMA resin may have a melt index (MI, ASTM D1238, 230°C, 3.8 kg load) of 1 to 12 g / 10 min and a weight average molecular weight of 10,000 to 120,000 g / mol (MW).

[0018] Additionally, the multilayer transparent soundproofing panel can have a pencil hardness value of 2H or higher.

[0019] Additionally, the multilayer transparent soundproofing panel can have a light transmittance of 85.0% or more.

[0020] According to the present disclosure, a multilayer transparent soundproofing panel having excellent soundproofing performance and transparency without hard coating, as well as excellent impact resistance, weather resistance, and scratch resistance, can be provided.

[0021] FIG. 1 illustrates a multilayer transparent soundproofing panel according to one embodiment of the present disclosure.

[0022] FIG. 2 illustrates a multilayer transparent soundproofing panel according to another embodiment of the present disclosure.

[0023] FIG. 3 illustrates a multilayer transparent soundproofing panel according to another embodiment of the present disclosure.

[0024] Figures 4a and 4b show the results of measuring the cross-sectional image of Example 2 using an optical microscope.

[0025] Figure 5 shows the results of measuring the change in yellowing over time in Example 2 and Comparative Examples 3 to 5.

[0026] Figure 6 is an actual image of a multilayer transparent soundproofing panel according to the present disclosure.

[0027] The present disclosure provides, in one embodiment, a multilayer transparent soundproof panel comprising a core layer including a polycarbonate (hereinafter, PC) resin, an ultraviolet stabilizer, an antioxidant, and a flame retardant, and a surface layer formed on one or both sides of the core layer and including a polymethyl methacrylate resin, an ultraviolet stabilizer, a slip agent, an antioxidant, and a chemically resistant antioxidant.

[0028] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the present disclosure. However, the present disclosure may be implemented in various different embodiments and is not limited to the embodiments described herein. Like reference numerals designate similar parts throughout the specification.

[0029] The present disclosure provides, in one embodiment, a multilayer transparent soundproof panel comprising a core layer including a polycarbonate (hereinafter, PC) resin, an ultraviolet stabilizer, an antioxidant, and a flame retardant, and a surface layer formed on one or both sides of the core layer and including a polymethyl methacrylate (hereinafter, PMMA) resin, an ultraviolet stabilizer, a slip agent, an antioxidant, and a chemically resistant antioxidant.

[0030] The core layer plays a role in alleviating impact applied from the outside, and specifically, the core layer absorbs and alleviates the impact of the external impact applied to the surface layer described below, thereby minimizing breakage and deformation of the multilayer transparent soundproofing panel.

[0031] Additionally, the core layer may have a thickness of 5 to 20 mm, specifically 8 to 15 mm, and more specifically 10 mm.

[0032] If the thickness of the core layer is less than 5 mm, it will not have an impact-resistant effect, and if the thickness exceeds 20 mm, the weight of the product will increase and the manufacturing cost may increase.

[0033] The core layer may include a PC resin, an ultraviolet stabilizer, an antioxidant, and a flame retardant. Specifically, the core layer may include 0.1 to 1 part by weight of an ultraviolet stabilizer, 0.1 to 1 part by weight of an antioxidant, and 0.1 to 1 part by weight of a flame retardant, based on 100 parts by weight of the PC resin.

[0034] The PC resin constituting the core layer has a melting index (MI) of 5 to 12 g / 10 min and a weight average molecular weight of 5,000 to 30,000 g / mol.

[0035] If the MI value of the PC resin forming the core layer is less than 5, workability is poor due to high viscosity, and flow marks or wave patterns may occur during manufacturing due to a large MI value difference with the PMMA resin forming the surface layer. If the MI value exceeds 12, workability is improved, but there is a problem of deterioration in mechanical properties.

[0036] In addition, if the weight average molecular weight of the PC resin is less than 5,000, the impact strength, which is a mechanical property of the soundproof panel, may be reduced, and if the weight average molecular weight exceeds 30,000, the flowability of the resin may be reduced, which may increase the molding defects during extrusion molding.

[0037] The core layer includes a UV stabilizer to prevent discoloration of the soundproof panel due to ultraviolet rays. Specifically, the core layer may include 0.1 to 1 part by weight of the UV stabilizer based on 100 parts by weight of PC resin, and more specifically, 0.5 parts by weight.

[0038] If the content of the UV stabilizer is less than 0.1 part by weight, the problem of yellowing or deterioration of the soundproof panel due to UV rays cannot be improved, and if the content of the UV stabilizer exceeds 1 part by weight, the expected effect is not achieved compared to the amount input, and the durability of the soundproof panel may be reduced and the manufacturing cost may increase.

[0039] UV stabilizers include 2,4-di-t-butyl-6-(5-chlorobenzotriazol-2-yl)phenol, 2-(2'-hydroxy-5'-oxyphenyl)benzotriazole, 2-(2'-hydroxymethylphenyl)benzotriazole, 2-[2'-hydroxy-3',5'-bis(α,α-dimethylbenzylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-dibutylphenyl)benzotriazole, 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3',5'-ditert-amyl)benzotriazole, 2,2'-methylene It may be at least one selected from the group consisting of bis[4-(1,1,3,3-tetramethylbutyl)-6-(2-N-benzotriazo-2-yl)phenol], 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-hexyloxyl-phenol and 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol, and specifically, it may be 2,4-di-t-butyl-6-(5-chlorobenzotriazol-2-yl)phenol.

[0040] If the content of antioxidant is less than 0.1 part by weight, the anti-oxidation effect of the soundproofing panel is minimal, and if the content of antioxidant is more than 1 part by weight, it may not only reduce the durability of the soundproofing panel but also increase the manufacturing cost.

[0041] The antioxidant may be at least one selected from the group consisting of N,N'-hexamethylene bis(3,5-di-t-butyl-4-hydroxy-hydroxycyanamide), pentaerythritol tetrabis(3-(3,5-di-tetra-butyl-4-hydroxypentylhydroxyphenyl)propionate), octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)-propionate, thiodiethylene bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], bis-(2,4-di-t-butylphenol) pentaerythritol diphosphite, tris(2,4-di-t-butylphenyl)phosphate, and specifically, N,N'-hexamethylene bis(3,5-di-t-butyl-4-hydroxy-hydroxycyanamide).

[0042] The core layer may contain a flame retardant to ensure flame retardancy of the soundproofing panel. Specifically, the core layer may contain 0.1 to 1 part by weight of the flame retardant based on 100 parts by weight of PC resin, and more specifically, 0.5 parts by weight.

[0043] If the flame retardant content is less than 0.1 part by weight, the soundproof panel cannot exhibit flame retardant effect, and if the flame retardant content exceeds 1 part by weight, it may not only reduce the durability of the soundproof panel but also increase the manufacturing cost.

[0044] The flame retardant may be one selected from the group consisting of non-halogenated, phosphorus-based and combinations thereof, and specifically, may be a phosphorus-based flame retardant.

[0045] The surface layer is formed on one or both sides of the core layer and contains PMMA resin, UV stabilizer, slip agent, antioxidant, and chemically resistant antioxidant.

[0046] The surface layer can improve the scratch resistance of the multilayer soundproofing panel.

[0047] The surface layer may be formed in a flat structure and may have a roughened portion (21) on one or both sides. Specifically, in order to improve the contamination prevention effect, it is preferable that the roughened portion (21) be formed on both sides of the core layer.

[0048] The uneven portion (21) primarily serves to reduce the intensity of noise, and when the uneven portion (21) is formed on one side, it is preferable to install it in the direction in which noise is generated.

[0049] Additionally, the surface layer may have a thickness of 100 to 1,000 μm, specifically 200 to 600 μm, and more specifically 200 to 500 μm.

[0050] If the thickness of the surface layer is less than 100 ㎛, the light transmittance is poor and improved scratch resistance cannot be achieved. If the thickness exceeds 1,000 ㎛, the flame retardancy and physical properties of the soundproof panel may deteriorate, and it is not economically desirable.

[0051] The surface layer may include a PMMA resin, an ultraviolet stabilizer, a slip agent, and a chemically resistant antioxidant. Specifically, the surface layer may include 0.1 to 15 parts by weight of an ultraviolet stabilizer, 0.1 to 1 part by weight of a slip agent, and 0.1 to 1 part by weight of a chemically resistant antioxidant, based on 100 parts by weight of PMMA resin.

[0052] The PMMA resin constituting the surface layer has a melting index (MI) of 1 to 12 g / 10 min and a weight average molecular weight of 10,000 to 120,000 g / mol.

[0053] If the PMMA resin forming the surface layer has an MI value of less than 1, workability is poor due to high viscosity, and flow marks or wave patterns may occur during manufacturing due to a large MI value difference from the PC resin forming the core layer. If the MI value exceeds 12, workability is improved, but there is a problem of deterioration in mechanical properties.

[0054] The surface layer includes a UV stabilizer to prevent discoloration of the soundproofing panel. Specifically, the surface layer may include 0.1 to 15 parts by weight of the UV stabilizer based on 100 parts by weight of PMMA resin, and more specifically, 7 parts by weight.

[0055] If the content of the UV stabilizer is less than 0.1 parts by weight, the problem of yellowing or deterioration of the soundproof panel due to UV rays cannot be improved, and if the content of the UV stabilizer exceeds 15 parts by weight, the expected effect is not achieved compared to the amount input, and the durability of the soundproof panel may be reduced and the manufacturing cost may increase.

[0056] The UV stabilizer can be the same as that used for the core layer.

[0057] The surface layer includes a slip agent to further enhance the scratch resistance of the soundproofing panel. Specifically, when the surface layer is formed on one or both sides of the core layer, the slip agent can further enhance the scratch resistance through its slip properties.

[0058] The surface layer may contain 0.1 to 1 part by weight of a slip agent based on 100 parts by weight of PMMA resin, and more specifically, may contain 0.5 parts by weight.

[0059] If the content of the slip agent is less than 0.1 part by weight, there is little improvement in the slipperiness of the surface layer, and if the content of the slip agent exceeds 1 part by weight, the defect rate may increase due to the slipperiness.

[0060] If the content of antioxidant is less than 0.1 part by weight, the anti-oxidation effect of the soundproofing panel is minimal, and if the content of antioxidant is more than 1 part by weight, it may not only reduce the durability of the soundproofing panel but also increase the manufacturing cost.

[0061] The antioxidant may be the same as that used in the core layer, and may specifically include 0.2 parts by weight.

[0062] The surface layer includes a chemical-resistant antioxidant to improve chemical resistance and impart thermal stability during compounding. Specifically, the surface layer may include 0.1 to 1 part by weight of the chemical-resistant antioxidant based on 100 parts by weight of PMMA resin, and more specifically, 0.3 parts by weight.

[0063] If the content of the chemical antioxidant is less than 0.1 part by weight, the chemical resistance and heat stability of the soundproofing panel are minimal, and if the content of the antioxidant exceeds 1 part by weight, it may not only reduce the durability of the soundproofing panel but also increase the manufacturing cost.

[0064] Bis[3,3-bis-(4'-hydroxy-3'-tert-butylphenyl)butanoic-acid]-glycolester can be used as a chemical-resistant antioxidant. This is a unique substance with a structure that has an ester group, and has chemical resistance to salt (Cl) and alcohol, in particular. In addition, it has the advantage of excellent resistance to sulfur dioxide (SO2).

[0065] The surface layer contains both an antioxidant and a chemical-resistant antioxidant, which can produce a synergistic effect.

[0066] A multilayer transparent soundproof panel manufactured according to the present disclosure may have a pencil hardness value of 2H or higher and a light transmittance of 85.0% or higher.

[0067] As a result, the transparent soundproof panel according to the present invention has excellent surface hardness values ​​without hard coating, as well as excellent weather resistance and scratch resistance, and can have high light transmittance.

[0068]

[0069] Hereinafter, the present disclosure will be described in more detail using examples. It will be apparent to those skilled in the art that these examples are intended solely to illustrate the present disclosure more specifically and that the scope of the present disclosure is not limited by them.

[0070]

[0071] <Example>

[0072] Examples 1 to 6

[0073] A soundproof panel with excellent transparency was manufactured by mixing 0.5 parts by weight of a UV stabilizer, 0.4 parts by weight of an antioxidant, and 0.5 parts by weight of a flame retardant with 100 parts by weight of a PC resin having a melting index of 7 g / 10 min and a weight average molecular weight of 50,000 g / mol and coextruding the mixture into a core layer, and then mixing 7 parts by weight of a UV stabilizer, 0.5 parts by weight of a slip agent, 0.4 parts by weight of an antioxidant, and 0.3 parts by weight of a chemical-resistant antioxidant with 100 parts by weight of a PMMA resin having a melting index of 2 g / 10 min and a weight average molecular weight of 85,000 g / mol and coextruding the mixture into a surface layer on both sides of the core layer surface.

[0074] At this time, the thickness of the core layer and the thickness of the surface layer were manufactured as shown in Table 1 below.

[0075] Surface layer Core layer Surface layer Example 1100 ㎛9.8 mm100 ㎛ Example 2200 ㎛9.6 mm200 ㎛ Example 3400 ㎛9.2 mm400 ㎛ Example 4600 ㎛8.4 mm600 ㎛ Example 5800 ㎛8.2 mm800 ㎛ Example 61,000 ㎛8.0 mm1,000 ㎛

[0076]

[0077] <Comparative Example>

[0078] Comparative Examples 1 to 4

[0079] It was manufactured in the same manner as Example 2, but the thickness of the core layer and the thickness of both surface layers were adjusted, and manufactured as shown in Table 2 below.

[0080] Surface layer Core layer Surface layer Note Comparative example 150 ㎛ 9.9 mm 50 ㎛ Same as Example 2 Combination Comparative example 2200 ㎛ 9.6 mm 200 ㎛ Chemical resistance Antioxidant excluded Comparative example 3200 ㎛ 9.6 mm 200 ㎛ UV stabilizer 1.0 parts by weight Comparative example 4200 ㎛ 9.6 mm 200 ㎛ UV stabilizer 15.0 parts by weight

[0081] Comparative Example 5

[0082] Soundproofing panels were manufactured using PC resin alone.

[0083]

[0084] Comparative Example 6

[0085] Soundproofing panels were manufactured using PMMA resin alone.

[0086]

[0087] <Example of an exam>

[0088] Test Example 1: Pencil hardness value analysis

[0089] The pencil hardness values ​​of the soundproofing panels manufactured according to Examples 1 to 6 and Comparative Examples 1 to 6 were measured. Table 3 below shows the results.

[0090] Pencil hardness value was measured by fixing a pencil at a load of 1.0 kg and an angle of 45°, and then scratching the surface of the specimen according to pencil hardness to determine whether it was scratched visually. This serves as a criterion for judging scratch resistance.

[0091] Classification Pencil Hardness Value Example 12H Example 22H Example 32H Example 42H Example 52H Example 62H Comparative Example 1B Comparative Example 22H Comparative Example 32H Comparative Example 4H Comparative Example 52B Comparative Example 62H

[0092] As can be seen in Table 3, Examples 1 to 6, in which the thickness of the surface layer is 100 ㎛ or more, all have pencil hardness values ​​of 2H or more, whereas Comparative Examples 1 and 4 to 6 all fall short of this. Consequently, it was confirmed that the scratch resistance of the soundproof panel can be improved by forming the thickness of the surface layer to 100 ㎛ or more.

[0093]

[0094] Test Example 2: Analysis of light transmittance according to surface layer thickness

[0095] The light transmittance of the soundproofing panels manufactured according to Examples 2 and 3 and Comparative Examples 5 and 6 was analyzed. Table 4 below shows the results.

[0096] Light transmittance was measured using a spectrophotometer (CM-3600D, Minolta).

[0097] Light transmittance comparison example 587.0% comparison example 691.8% embodiment example 291.4% embodiment example 686.9%

[0098] As can be seen in Table 5 above, all examples have better light transmittance than Comparative Example 5, which is manufactured using only PC resin. That is, it can be confirmed that light transmittance is improved by forming a surface layer composed of PMMA on a PC core layer with poor light transmittance.

[0099]

[0100] Test Example 3: Flame Retardancy Analysis

[0101] The flame retardancy of soundproofing panels manufactured according to Example 2 and Comparative Example 5 was analyzed. Table 5 below shows the results.

[0102] Flame retardant performance analysis was performed according to the UL 94 V Test (Vertical Burning Test) standard.

[0103] Comparison of flame retardancy levels Example 5V-2 Example 2V-0

[0104] As can be seen in Table 6, the soundproofing panel using only PC resin is rated at V-2, but Example 2 is rated at V-0, showing superior flame retardancy.

[0105]

[0106] Test Example 4: Saltwater Spray Evaluation

[0107] The salt water spray resistance of the soundproofing panels manufactured according to Example 2, Comparative Example 2, Comparative Example 5, and Comparative Example 6 was evaluated.

[0108] Table 6 below shows the results.

[0109] The salt spray resistance was evaluated according to the severity level 3 of the KS C IEC600682-52 standard, and the change in cloudiness (△Haze) was measured.

[0110] Degree of change in blurriness (△Haze) Example 20.2 Comparative Example 20.5 Comparative Example 50.5 Comparative Example 60.6

[0111] As can be seen in Table 6, the multilayer soundproof panel to which the chemical antioxidant was applied showed a 0.2 increase in cloudiness change, but Comparative Examples 2, 5, and 6 showed a 0.5 increase, confirming that the role of the chemical antioxidant was important and that Example 2 had better salt water resistance.

[0112]

[0113] Test Example 5: Weatherability Evaluation

[0114] The weather resistance of soundproofing panels manufactured according to Example 2 and Comparative Examples 3 to 5 was evaluated. Table 7 below shows the results.

[0115] The weathering resistance evaluation was conducted using a Q-UV tester (QUV / se, Q-LAB) according to ASTM E313-73 standard, with UV lamp wavelength 340 nm, light intensity 0.71 W / ㎡, 1 cycle (UV mode 4 hr, condensation 4 hr), and then the experiment was conducted for up to 1500 hours in 200-hour increments, and the yellowing index (YI) change (△YI) was measured.

[0116] Classification△YI Example 22.06 Comparative Example 35.12 Comparative Example 41.85 Comparative Example 59.98

[0117] As can be seen in Table 7, Example 2, which used an appropriate amount of UV stabilizer, showed excellent yellowing degree change of 2, whereas Comparative Example 5, which was manufactured using only PC as a single material, showed very poor weather resistance with a yellowing degree change of about 10. In addition, Comparative Example 2 showed insufficient weather resistance due to a small amount of UV stabilizer, and Comparative Example 4, to which 15 parts by weight of UV stabilizer was added, showed very poor appearance quality due to the generation of a large amount of fume gas and paraffin, and although the weather resistance is at the same level as Example 2, it is difficult to apply it in practice due to the lack of unit price competitiveness.

[0118] The present disclosure described above with reference to the attached drawings can be modified and changed in various ways by those skilled in the art, and such modifications and changes should be interpreted as being included within the scope of the present disclosure.

[0119] According to the present disclosure, a multilayer transparent soundproofing panel having excellent soundproofing performance and transparency without hard coating, as well as excellent impact resistance, weather resistance, and scratch resistance, can be provided.

Claims

1. A core layer containing polycarbonate resin, UV stabilizer, antioxidant and flame retardant, A surface layer formed on one or both sides of the core layer and containing polymethyl methacrylate resin, an ultraviolet stabilizer, a slip agent, an antioxidant, and a chemically resistant antioxidant. Multilayer transparent soundproofing panel.

2. In paragraph 1, The above surface layer has a rough surface, Multilayer transparent soundproofing panel.

3. In paragraph 1, The above core layer is, Based on 100 parts by weight of the PC resin, it comprises 0.1 to 1 part by weight of a UV stabilizer, 0.1 to 1 part by weight of an antioxidant, and 0.1 to 1 part by weight of a flame retardant. Multilayer transparent soundproofing panel.

4. In paragraph 1, The above surface layer is, Based on 100 parts by weight of the above PMMA resin, it comprises 0.1 to 15 parts by weight of a UV stabilizer, 0.1 to 1 part by weight of a slip agent, 0.1 to 1 part by weight of an antioxidant, and 0.1 to 1 part by weight of a chemical-resistant antioxidant. Multilayer transparent soundproofing panel.

5. In paragraph 1, The above core layer is, It has a thickness of 5 to 20 mm, The above surface layer is, Having a thickness of 100 to 1,000 ㎛, Multilayer transparent soundproofing panel.

6. In paragraph 1, The above PC resin has a melting index (MI) of 5 to 12 g / 10 min, The molecular weight is 5,000 to 30,000 g / mol, The above PMMA resin has a melting index (MI) of 1 to 12 g / 10 min, With a weight average molecular weight of 10,000 to 120,000 g / mol, Multilayer transparent soundproofing panel.

7. In paragraph 1, Having a pencil hardness value of 2H or higher, Multilayer transparent soundproofing panel.

8. In paragraph 1, Having a light transmittance of 85.0% or more, Multilayer transparent soundproofing panel.

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