Sound-absorbing interior material for electric vehicles

Abstract

The present invention relates to a sound-absorbing interior material for an electric vehicle comprising a pouch having a certain internal receiving space and waste fibers embedded in the pouch receiving space.

Description

Technology Field

[0001] The present invention relates to a sound-absorbing interior material for electric vehicles, and specifically, to a sound-absorbing interior material filled between the body panels of an electric vehicle. Background Technology

[0002] Various forms of nonwoven fabric formulations are applied to automobiles for the purposes of sound insulation and sound absorption. However, in most cases, parts coated with films such as ethylene vinyl acetate (EVA), polyethylene (PE), and polypropylene (PP) are used for carpets or headlinings for purposes such as sound absorption, sound insulation, waterproofing, dustproofing, and moldability. In reality, most of these parts—waste parts generated after vehicle scrapping, defective products from the manufacturing process, or scrap generated after product molding—are not recycled and are instead processed as heat sources in places such as cement kilns or combined heat and power plants.

[0003] In particular, to reduce noise generated from wheels during driving for quieter vehicle operation, wheel guard materials are being transitioned from conventional olefin-based polymer injection-molded products to non-woven fabric composite products utilizing fibers. However, there are limitations to widespread adoption due to the problem of increased component costs compared to olefin-based polymer molded products. Additionally, the typical surface weight of non-woven fabrics for automotive wheel guards is 800 to 1600 g per square meter; however, the use of such non-woven fabrics results in higher weight and a more complex manufacturing process compared to conventional injection-molded types, leading to increased component manufacturing costs and limiting their application to high-end vehicle models.

[0004] In addition to this, technologies for recycling waste automotive carpets and carpet scraps through various methods are being reported.

[0005] Conventional Korean Patent No. 10-1272552 (published June 11, 2013) discloses a sound-absorbing and insulating material manufactured through a process of finely grinding waste sheets, mixing the resulting ground material with polyester fibers, low-melting-point polyester fibers, polypropylene fibers, and hemp, and then cutting. However, when manufacturing by mixing urethane foam with polyester fibers, there is a problem of insufficient rigidity because materials with different shapes are bonded together using a low-melting-point polyester binder. Additionally, although a needle punching process is included in the manufacturing process, the fibers themselves become intertwined rather than intertwined with the urethane foam and fibers. Consequently, the overall rigidity of the recycled sound-absorbing material is insufficient, leading to limitations in applications such as use in sound-absorbing components for automobiles where rigidity is not required.

[0006] In addition, Korean Registered Patent No. 10-1069903 (published on October 5, 2011) discloses a manufacturing method in which polyester is used as a surface nonwoven fabric, an extruded sheet containing 30 to 50 weight percent of recycled chips is used as a base layer, and a laminate composed of a back-side sound-absorbing nonwoven fabric layer made of polyester is needle-punched. However, this method recycles materials from products extruded and injection-molded from materials such as polyethylene, polypropylene, wood flour, and carbon black, and is limited to board-type products requiring hardness, and has the problem of increased weight compared to fiber materials.

[0007] In addition, Korean Registered Patent No. 10-1181201 (published September 18, 2021) discloses a method for manufacturing a wheel guard for a vehicle, comprising a step of forming a first felt layer and a second felt layer by carding and needle punching polyester fibers including low-melting point polyester fibers and general polyester fibers to form a felt layer, and a lamination step of laminating and needle punching the first felt layer and the second felt layer. However, it does not consider at all the eco-friendly effects of utilizing recycled fibers separated from waste felt or waste scrap.

[0008] Therefore, research is required to recycle recycled fibers discarded from waste parts, defective products generated during the manufacturing process, or scrap, and utilize them as sound-absorbing materials for noise reduction. Prior art literature

[0009] Korean Registered Patent No. 10-1272552 (Published June 11, 2013) Korean Registered Patent No. 10-1069903 (Published October 5, 2011) Korean Registered Patent No. 10-1181201 (Published September 18, 2021) The problem to be solved

[0010] The problem that the present invention aims to solve is to provide a sound-absorbing material for electric vehicles that is environmentally friendly and capable of significantly reducing manufacturing costs, while exhibiting physical properties equivalent to commercially available sound-absorbing materials, by utilizing previously used waste synthetic fibers and applying them to the sound-absorbing material for electric vehicles.

[0011] Another problem that the present invention aims to solve is to provide a sound-absorbing material for electric vehicles that exhibits excellent sound absorption performance above a certain frequency. means of solving the problem

[0012] In one embodiment, the present invention relates to a sound-absorbing interior material for an electric vehicle comprising a pouch having a certain receiving space inside and waste fibers embedded in the pouch receiving space.

[0013] In addition, the pouch may be one or more selected from the group consisting of polyolefin, polyvinylidene chloride, nylon, and polyethylene terephthalate.

[0014] In addition, waste fibers may be scrap generated from the carding process or scrap generated from the trimming process.

[0015] In addition, the waste fiber may be polyethylene terephthalate or low-density polyethylene.

[0016] In addition, the fineness of the waste fibers can be 5 to 9 denier.

[0017] In addition, the sound-absorbing interior material can have a sound absorption coefficient of 0.43–0.95% at frequencies of 400–10,000 Hz in the 1 / 3 Octave band of a semi-reverberation chamber. Effects of the invention

[0018] According to the present invention, by utilizing previously used waste fibers and applying them to sound-absorbing materials for electric vehicles, it is possible to achieve physical properties equivalent to those of commercially available sound-absorbing materials while being eco-friendly and significantly reducing manufacturing costs.

[0019] In addition, it can exhibit excellent sound absorption performance above a certain frequency. Brief explanation of the drawing

[0020] FIG. 1 is a cross-sectional view showing a sound-absorbing interior material according to one embodiment of the present invention. Figure 2 is a schematic diagram showing a simple reverberation chamber. Figure 3 shows the results of the sound absorption performance evaluation according to the fiber fineness. Figure 4 shows the results of the sound absorption performance evaluation of sound-absorbing interior materials manufactured according to the examples and comparative examples. Specific details for implementing the invention

[0021] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. However, the present invention may be implemented in various different embodiments and is not limited to the embodiments described herein. Throughout the specification, similar parts are denoted by the same reference numerals.

[0023] In the present invention, the term “carding process” refers to a process of combing a bundled fabric to completely separate it, thereby removing impurities or short fibers and separating the fibers one by one, and “carding process scrap” refers to by-products filtered out by the combing. Additionally, the term “trimming process” refers to a process of removing unnecessary edges or burrs formed on the outer surface of a product molded by a mold, and “trimming scrap” refers to edges or burrs generated during the trimming process.

[0024] In one embodiment, the present invention relates to a sound-absorbing interior material for an electric vehicle comprising a pouch having a certain receiving space inside and waste fibers embedded in the pouch receiving space.

[0025] The pouch may be manufactured from one or more fibers selected from the group consisting of polyolefin, polyvinylidene chloride, nylon, and polyethylene terephthalate, and specifically may be polypropylene (PP) or polyethylene terephthalate (PET).

[0026] For example, the pouch may be a three-way sealing nonwoven fabric in which an embossed PET spun-bundled nonwoven fabric, a PP spun-bundled nonwoven fabric, and an embossed PET spun-bundled nonwoven fabric are sequentially laminated and sealed.

[0027] Polypropylene may be manufactured using a melt index of 30 to 40 g / 10 min, specifically 15 to 25 g / 10 min.

[0028] The nonwoven fabric may be made of long fibers or short fibers, and preferably may be a long fiber nonwoven fabric.

[0029] The long fiber nonwoven fabric may be manufactured using one method selected from the group consisting of the spunbond method, the meltblown method, the needle punching method, and the spunlace method, and specifically, it may be the spunbond method.

[0030] The pouch is sewn along the edges to have a certain internal storage space, and the storage space can be filled with waste fibers.

[0031] The pouch is formed with an opening that can be sealed after being filled with the waste fibers described below. That is, after filling the receiving space of the pouch with waste fibers, it can be sealed by a sewing process or an adhesive process using adhesives.

[0032] In addition, the pouch can be formed in various shapes, specifically, it can be formed in one shape selected from the group consisting of squares, triangles, and circles, and more specifically, it can be formed in a square or rectangular shape.

[0033] Waste fibers may be scrap generated from the carding process or scrap generated from the trimming process, and preferably may be a mixture.

[0034] Specifically, waste fibers can use 0 to 100 weight percent of scrap generated in the carding process and 0 to 100 weight percent of scrap generated in the trimming process, and more specifically, 50 weight percent of scrap generated in the carding process and 50 weight percent of scrap generated in the trimming process can be used.

[0035] Waste fibers can be polyethylene terephthalate or low-density polyethylene.

[0036] The fineness of the pulmonary fibers can be 5 to 9 denier, and more specifically, 6 to 8 denier.

[0037] If the fineness of the waste fibers is less than 5 denier, there is a problem that the waste fibers may protrude outside the pouch, and if the fineness exceeds 10 denier, the sound absorption rate decreases and the flexibility of the sound-absorbing interior material may decrease.

[0038] The waste fibers can be short fibers with an average fiber length of 10 to 30 mm. Specifically, if the average fiber length is shorter than 10 mm, the bonding strength between the fibers decreases, and they may protrude or detach from the outside of the pouch. If it is longer than 30 mm, the bonding strength is excellent, but the sound absorption rate may decrease.

[0039] The waste fiber may be a hollow fiber, and the size of the hollow may be 1 to 50 µm, specifically 10 to 40 µm, and more specifically 20 to 30 µm.

[0040] If the size of the hollow is less than 1 μm, there is a problem with handling during manufacturing, and if it exceeds 50 μm, there is a problem with the sound absorption rate decreasing.

[0041] Waste fibers can be sealed with approximately 80 to 90 volume% filled based on 100 volume% of the internal space of the pouch, specifically 85 to 90 volume%, and more preferably 90 volume% filled.

[0042] If the content of waste fibers in the pouch is less than 80 volume%, there is a problem that the sound absorption rate and sound insulation rate are reduced due to the waste fibers, and if it exceeds 90 volume%, the freedom of the sound-absorbing interior material is reduced, making it difficult to fill in body panels at various locations.

[0043] The sound-absorbing interior material can have a sound absorption coefficient of 0.43 to 0.95% at frequencies of 400 to 10,000 Hz in the 1 / 3 Octave band of a semi-reverberation chamber.

[0045] The present invention will be described in more detail below using examples. These examples are solely for the purpose of more specifically explaining the present invention, and it is obvious to those skilled in the art that the scope of the present invention is not limited by them.

[0047] Preliminary Exam

[0048] The sound absorption performance according to the fineness of the fibers was analyzed.

[0049] To evaluate the sound absorption performance according to fineness, samples of 10-denier felt and 6-denier felt were prepared and evaluated, and the results are shown in Fig. 3. Fig. 3 shows the analysis of the sound absorption performance according to the fiber denier.

[0050] Referring to Figure 3, it can be seen that 6-denier felt exhibits better sound absorption performance than 10-denier felt.

[0052] <Example>

[0053] A pouch was manufactured by producing a three-way sealing nonwoven fabric in which an embossed PET spun-bundled nonwoven fabric, a PP spun-bundled nonwoven fabric, and an embossed PET spun-bundled nonwoven fabric are sequentially laminated and sealed.

[0054] Next, waste fibers (PET, fineness 6) generated during the carding process were filled into the internal space of the pouch to make up about 90% of the volume, and a sound-absorbing interior material was manufactured through sewing.

[0056] <Comparative Example>

[0057] I purchased and prepared commercially available polyurethane foam interior materials.

[0059] <Test Example>

[0060] Test Example 1: Sound Absorption Performance Analysis

[0061] The sound absorption performance of the sound-absorbing interior materials manufactured according to the examples and comparative examples was analyzed using the Semi-Reverberation Chamber (SRC) method, which is one-third the size of a standard reverberation chamber.

[0062] The sound absorption rate was calculated using the following mathematical formula 1.

[0063] [Mathematical Formula 1]

[0064]

[0065] V: Reverberation chamber volume (6.44 m²) S: Sample area C: Correction factor

[0066] TRO: Time measured for reverberation in an empty cabin

[0067] TR: Time to measure reverberation time after sample injection

[0068] Measurement conditions

[0069] Measurements were taken using a microphone with a frequency range between 400Hz and 10,000Hz (15 bands of 1 / 3 octave) (Temperature: 22°C ± 3°C, Humidity: 60% ± 10%)

[0070] Figure 4 shows the results of evaluating the sound absorption performance of the example and the comparative example.

[0071] Referring to FIG. 4, it can be seen that the sound-absorbing interior material manufactured according to the embodiment exhibits superior sound absorption performance compared to the interior material manufactured from conventional polyurethane foam. In particular, it can be seen that the sound absorption performance is even better in the high frequency range.

[0073] Test Example 2: Analysis of Degrees of Freedom, Shielding Performance, and Ventilation

[0074] The degrees of freedom, shielding performance, and ventilation of sound-absorbing interior materials manufactured according to the examples and comparative examples were analyzed and are shown in Table 1 below.

[0075] -Analysis Method-

[0076] Degrees of freedom: Determines the manufacturing size and degree of shape deformation of a part

[0077] Analysis of shielding performance and ventilation: Air permeability was evaluated by measuring it. The air permeability evaluation was performed by passing air vertically through a certain area and under pressure of the fabric and measuring the amount of air or air flow velocity transmitted over a certain area for a certain period of time.

[0078] division Comparative example Examples Degrees of freedom award award shielding award middle Sound absorption performance under award Ventilation under award

[0079] Referring to Table 1, the degree of freedom of the example was judged to be at a similar level compared to the comparative example, and although the shielding performance was slightly reduced, it received an excellent evaluation for sound absorption performance and ventilation function. Consequently, according to the present invention, by applying previously used waste fibers as a sound-absorbing material for electric vehicles, it is possible to achieve physical properties equivalent to those of conventional commercially available sound-absorbing materials while being eco-friendly and significantly reducing manufacturing costs. Explanation of the symbols

[0080] 1: Sound-absorbing interior material 100: Pouch 200: Waste fiber

Claims

Claim 1 A sound-absorbing interior material for an electric vehicle, comprising a pouch having a certain internal space and waste fibers embedded in the pouch's space, wherein the pouch is composed of a three-way sealing nonwoven fabric in which an embossed PET spunbund nonwoven fabric, a PP spunbund nonwoven fabric, and an embossed PET spunbund nonwoven fabric are sequentially laminated and sealed, and wherein the waste fibers are filled at 80 to 90 volume% based on 100 volume% of the pouch's space, and wherein the waste fibers are scrap generated from a carding process or scrap generated from a trimming process. Claim 2 delete Claim 3 delete Claim 4 In claim 1, the waste fiber is polyethylene terephthalate or low-density polyethylene, sound-absorbing interior material for electric vehicles. Claim 5 In claim 1, the sound-absorbing interior material for electric vehicles, wherein the fineness of the waste fiber is 5 to 9 denier. Claim 6 In claim 1, a sound-absorbing interior material for an electric vehicle having a sound absorption coefficient of 0.43 to 0.95% at a frequency of 400 to 10,000 Hz in the 1 / 3 Octave band of a semi-reverberation chamber.

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