Method for manufacturing low-noise tire including polyurethane sound-absorbing material, and low-noise tire using same

Abstract

The present invention relates to a method for manufacturing a low-noise tire including a polyurethane sound-absorbing material. The method for manufacturing a low-noise tire including a polyurethane sound-absorbing material comprises: a polyurethane foam preparation step for preparing a polyurethane foam by mixing a first reactant and a second reactant; a forming die placement step for forming an inner space by attaching a first die and a second die, which are fitted together, to the inner wall of the tire; a polyurethane foam injection and foaming step for injecting the polyurethane foam into the inner space of the forming die; a polyurethane foam curing step for curing the foamed polyurethane foam; and a forming die removal step for removing the forming die.

Description

Method for manufacturing a low-noise tire including polyurethane sound-absorbing material and a low-noise tire using the same

[0001] The present invention relates to a method for manufacturing a low-noise tire including a polyurethane sound-absorbing material and a low-noise tire using the same, and more specifically, to a method for manufacturing a low-noise tire including a polyurethane sound-absorbing material for manufacturing a low-noise tire without a sound-absorbing material bonding process by directly injecting and foaming polyurethane foam into the inner wall of the tire, and to a low-noise tire using the same.

[0002] Pneumatic tires generate resonant noise around 200 Hz and radiated noise above 500 Hz, which originate from the cavity created by the tire and rim structure.

[0003] The above-mentioned radiated noise is generated as a sound with sharp peaks inside the vehicle, causing discomfort to the driver and reducing ride comfort.

[0004] Recently, with the expansion of electric vehicles, there is a growing demand for improved ride comfort and reduction of external noise generated by tires as well as interior noise to improve vehicle quality.

[0005] Therefore, in order to reduce tire resonance noise, a method of attaching sound-absorbing material to the inner wall of the tire has been proposed.

[0006] However, when attaching sound-absorbing material to the inner wall of a tire, an additional process of applying adhesive to the inner wall of the tire and attaching the sound-absorbing material occurs after the tire is manufactured, and because workers attach the sound-absorbing material manually, there was a problem in that products of consistent quality were not produced.

[0007] Additionally, there was the inconvenience of having to additionally produce sound-absorbing materials that fit the tire depending on the tire's specifications and intended use.

[0008] The prior art invention, Korean Patent Publication No. 10-1901399 (September 17, 2018), relates to a method for manufacturing a tire and a tire manufactured using the same, characterized in that a polyurethane mixture is produced by mixing a first reactant and a second reactant, a first mold (100) and a second mold (100`) attached to a tire member (10) are rotated together with the tire member (10), and the polyurethane mixture is foamed onto the inner wall of the tire through a fixed foaming head (H) to form a polyurethane sound-absorbing member.

[0009] However, in the case of the conventional invention, since the foaming head (H) is fixedly arranged, the tire member must be rotated to foam the polyurethane foam over the entire inner wall of the tire, and when using a mold that guides only the width of the polyurethane foam and is arranged along the circumference direction over the entire inside of the tire member (10), such as the second mold (100`), it is difficult to obtain a polyurethane foam of uniform thickness, and there are problems in that it is difficult to demold after the polyurethane foaming work is completed.

[0010] Therefore, if a method for manufacturing a low-noise tire including a polyurethane sound-absorbing material is developed, which involves attaching a mold facing each other to the inner wall of the tire to form an internal space between the inner walls of the tire, and injecting and foaming polyurethane foam into the internal space to produce the tire, it will be possible to produce a low-noise tire equipped with a sound-absorbing material through a convenient process without moving or rotating the tire member.

[0011] In addition, when the molding mold (200) is placed on the inner wall of the tire and polyurethane foam is foamed, the polyurethane foam is foamed only in the internal space that is evenly formed, so that a sound-absorbing member with a uniform shape and quality can always be obtained.

[0012] In addition, if the molding mold (200) for polyurethane foaming is separated into pieces and placed, the molding mold can be easily fixed and can be easily demolded compared to the molding mold of the prior art, which was difficult to demold after work.

[0013] In addition, it will be possible to manufacture low-noise tires that include polyurethane sound-absorbing material in the inner wall of the tire without the additional process of applying adhesive to the inner wall of the tire and attaching sound-absorbing material.

[0014] Therefore, the purpose of the present invention is to solve all of the above-described problems.

[0015] According to the present invention, a mold is attached to the inner wall of a tire so as to face each other to form an internal space between the inner walls of the tire, and the mold (200) is divided into pieces such as a first mold (210) and a second mold (220), arranged to surround the entire inner wall of the tire, and polyurethane foam is injected into the inside thereof, thereby fixing the tire in one position without movement or rotation of the tire member, thereby providing a method for manufacturing a low-noise tire including a polyurethane sound-absorbing material in a convenient process, and a low-noise tire using the same.

[0016] In addition, another purpose is to provide a method for manufacturing a low-noise tire including a polyurethane sound-absorbing material, in which the polyurethane foam is foamed only in a uniformly formed internal space when the mold (200) is placed on the inner wall of the tire, thereby obtaining a sound-absorbing member with a uniform shape and quality at all times, and a low-noise tire using the same.

[0017] In addition, another purpose of the present invention is to provide a method for manufacturing a low-noise tire including a polyurethane sound-absorbing material, which is easy to install and easy to demold after work because the mold (200) is separated into pieces and placed, and a low-noise tire using the same.

[0018] In addition, another purpose of the present invention is to provide a method for manufacturing a low-noise tire including a polyurethane sound-absorbing material in the inner wall of the tire without the additional process of applying an adhesive to the inner wall of the tire and attaching a sound-absorbing material, and a low-noise tire using the same.

[0019] According to one aspect of the present invention, a method for manufacturing a low-noise tire (S10) including a polyurethane sound-absorbing material is provided, comprising a polyurethane foam preparation step (S100) of preparing a polyurethane foam (100) by mixing a first reactant and a second reactant, a molding mold arrangement step (S200) of attaching a first mold (210) and a second mold (220) that are fitted together to an inner wall of a tire to form an internal space, a polyurethane foam injection and foaming step (S300) of injecting polyurethane foam into the internal space of the mold, a polyurethane foam curing step (S400) of curing the foamed polyurethane foam, and a molding mold demolding step (S500) of demolding the mold.

[0020] More specifically, a method for manufacturing a low-noise tire including a polyurethane sound-absorbing material (S10) is provided, characterized in that the polyurethane foam preparation step (S100) includes a first reactant preparation step (S110) including an isocyanate component, a second reactant preparation step (S120) composed of a first polyol and a second polyol, and a reactant stirring step (S130) of stirring the first reactant and the second reactant to produce a polyurethane foam.

[0021] More specifically, a method for manufacturing a low-noise tire (S10) including a polyurethane sound-absorbing material is provided, characterized in that the first reactant is mixed in an amount of 0.35 to 0.45 parts by weight based on 1 part by weight of the second reactant.

[0022] More specifically, a method for manufacturing a low-noise tire (S10) including a polyurethane sound-absorbing material is provided, characterized in that the first reactant includes at least one selected from toluene diisocyanate, carbodiimide methylene diphenyl diisocyanate, monomeric methylene diphenyl diisocyanate, and polymeric diphenyl diisocyanate.

[0023] More specifically, a method for manufacturing a low-noise tire (S10) including a polyurethane sound-absorbing material is provided, characterized in that the second reactant is composed of a first polyol containing 85 to 95 wt% of a component having an OH value of 20 to 40 mgKOH / g and a second polyol containing 5 to 15 wt% of a component having an OH value of 20 to 60 mgKOH / g.

[0024] More specifically, a method for manufacturing a low-noise tire including a polyurethane sound-absorbing material (S10) is provided, characterized in that the second reactant includes 0.01 to 0.1 part by weight of a chain extender having a hydroxyl value (OH Value) of 900 to 1200 mgKOH / g based on 1 part by weight of the first polyol and second polyol mixed composition.

[0025] More specifically, a method for manufacturing a low-noise tire (S10) is provided, wherein the molding mold has a cross-section that is shaped like the letter 'ㄷ' and has an opening and a plurality of folded portions, and the openings are attached to the inner wall of the tire so as to face each other, thereby forming an internal space between the inner wall of the tire and including a polyurethane sound-absorbing material.

[0026] More specifically, a method for manufacturing a low-noise tire (S10) including a polyurethane sound-absorbing material is provided, characterized in that the molding mold further has a plurality of protrusions on the inner wall of the molding mold.

[0027] More specifically, a method for manufacturing a low-noise tire including a polyurethane sound-absorbing material (S10) is provided, characterized in that the molding molding arrangement step (S200) includes a first mold arrangement step (S210) of arranging a plurality of first molds having at least one fitting groove on a side surface at regular intervals on the inner wall of the tire, and a second mold arrangement step (S220) of attaching a second mold having at least one protrusion on a side surface to the inner wall of the tire by fitting it between the first molds.

[0028] More specifically, a method for manufacturing a low-noise tire including a polyurethane sound-absorbing material (S10) is provided, characterized in that the polyurethane foam injection and foaming step (S300) injects polyurethane foam through an injection port provided at a predetermined position in the mold.

[0029] More specifically, a method for manufacturing a low-noise tire including a polyurethane sound-absorbing material (S10) is provided, characterized in that the mold demolding step (S500) includes a second mold demolding step (S510) of demolding a second mold, and a first mold demolding step (S520) of demolding a first mold.

[0030] According to one embodiment of the present invention, a low-noise tire (10) including a polyurethane sound-absorbing material manufactured by a method for manufacturing a low-noise tire including a polyurethane sound-absorbing material (S10) is provided.

[0031] According to the present invention, a mold is attached to the inner wall of a tire so as to face each other to form an internal space between the inner walls of the tire, and the mold (200) is divided into pieces such as a first mold (210) and a second mold (220), arranged to surround the entire inner wall of the tire, and polyurethane foam is injected into the inside thereof, thereby fixing the tire in one position without movement or rotation of the tire member, thereby providing a method for manufacturing a low-noise tire including a polyurethane sound-absorbing material in a convenient process and a low-noise tire using the same.

[0032] In addition, a method for manufacturing a low-noise tire including a polyurethane sound-absorbing material, which can always obtain a sound-absorbing member of a uniform shape and quality by foaming polyurethane foam only in a uniformly formed internal space when the molding mold (200) is placed on the inner wall of the tire, and a low-noise tire using the same can be provided.

[0033] In addition, since the molding mold (200) is separated into pieces and placed, the molding mold is easy to install, and a method for manufacturing a low-noise tire including a polyurethane sound-absorbing material that is easy to demold after work can be provided, and a low-noise tire using the same can be provided.

[0034] In addition, a method for manufacturing a low-noise tire including a polyurethane sound-absorbing material in the inner wall of the tire without an additional process of applying an adhesive to the inner wall of the tire and attaching a sound-absorbing material, and a low-noise tire using the same can be provided.

[0035] FIG. 1 is an overall flowchart of a method (S10) for manufacturing a low-noise tire including a polyurethane sound-absorbing material according to one embodiment of the present invention.

[0036] Figure 2 is a detailed flowchart of a polyurethane foam preparation step (S100) according to one embodiment of the present invention.

[0037] Figure 3 is a detailed flowchart of a mold placement step (S200) according to one embodiment of the present invention.

[0038] Figure 4 is a combination flow diagram of a mold (200) according to one embodiment of the present invention.

[0039] Figure 5 is a perspective view of a combined mold (200) according to one embodiment of the present invention.

[0040] FIG. 6 is a drawing showing an injection method of a polyurethane foam injection and foaming step (S300) according to one embodiment of the present invention.

[0041] Figure 7 is a detailed flowchart of a mold demolding step (S500) according to one embodiment of the present invention.

[0042] Figure 8 is a cross-sectional view of a polyurethane foam (100) according to one embodiment of the present invention.

[0043] FIG. 9 is a cross-sectional view of a polyurethane foam (100) according to an additional embodiment of the present invention.

[0044] FIG. 10 is a perspective view of a low-noise tire (10) including a polyurethane sound-absorbing material according to one embodiment of the present invention.

[0045] The following detailed description of the present invention refers to the accompanying drawings, which illustrate specific embodiments in which the present invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the present invention. It should be understood that the various embodiments of the present invention, while different from each other, are not necessarily mutually exclusive. For example, specific shapes, structures, and characteristics described herein may be implemented in other embodiments without departing from the spirit and scope of the present invention. Furthermore, it should be understood that the positions or arrangements of individual components within each disclosed embodiment may be modified without departing from the spirit and scope of the present invention. Accordingly, the following detailed description is not intended to be limiting, and the scope of the present invention is defined only by the appended claims, along with the full scope of equivalents to which such claims are entitled, if properly described. Like reference numerals in the drawings designate the same or similar functionality throughout the several aspects.

[0046] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings so that a person having ordinary skill in the art to which the present invention pertains can easily practice the present invention.

[0047]

[0048] FIG. 1 is an overall flowchart of a method (S10) for manufacturing a low-noise tire including a polyurethane sound-absorbing material according to one embodiment of the present invention.

[0049] Referring to FIG. 1, a method for manufacturing a low-noise tire including a polyurethane sound-absorbing material (S10) may be composed of a polyurethane preparation step (S100), a mold placement step (S200), a polyurethane foam injection and foaming step (S300), a polyurethane foam curing step (S400), and a mold demolding step (S500).

[0050] More specifically, the polyurethane foam preparation step (S100) is a step of preparing a polyurethane foam (100) formed by mixing a first reactant and a second reactant. The first reactant and the second reactant will be described in detail in the detailed flowchart of Fig. 2.

[0051] The above mold placement step (S200) is a step of attaching a first mold (210) and a second mold (220) that can be fitted together to the inner wall of a tire to form an internal space into which polyurethane foam can be injected.

[0052] The above polyurethane foam injection and foaming step is a step of injecting the polyurethane foam (100) formed in the polyurethane preparation step (S100) into the internal space formed by the mold (200).

[0053] The above polyurethane foam curing step (S400) is a step in which the polyurethane foam injected into the internal space is cured by leaving it at room temperature for 30 seconds to 1 minute.

[0054] The above mold demolding step (S500) is a step of demolding the mold attached to the inner wall of the tire when the curing of the polyurethane foam (100) is complete.

[0055] Figure 2 is a detailed flowchart of a polyurethane foam preparation step (S100) according to one embodiment of the present invention.

[0056] Referring to FIG. 2, the polyurethane foam preparation step (S100) may be composed of a first reactant preparation step (S110), a second reactant preparation step (S120), and a reactant stirring step (S130).

[0057] In the first reactant preparation step (S110), the first reactant may include an isocyanate component. In addition, among the isocyanate components, the first reactant may include at least one isocyanate component selected from toluene diisocyanate, carbodiimide methylene diphenyl diisocyanate, monomeric methylene diphenyl diisocyanate, and polymeric diphenyl diisocyanate.

[0058] In the second reactant preparation step (S120), the second reactant may be composed of a first polyol and a second polyol.

[0059] The first polyol may be composed of 85 to 95 wt% of a component having an OH value of 20 to 40 mgKOH / g, and the second polyol may be composed of 5 to 15 wt% of a component having an OH value of 20 to 60 mgKOH / g.

[0060] When the hydroxyl value (OH value) of the first polyol is less than 20-40 mgKOH / g of polyol and 30 wt%, the problem of reduced elasticity may occur. When the hydroxyl value (OH value) of the second polyol is less than 20-60 mgKOH / g of polyol and 5 wt%, the problem of increased vibration transmission from the tire may occur. When it exceeds 15 wt%, the problem of foam deformation and reduced permanent compression set rate may occur.

[0061] When the ratio of the first polyol component in the mixing ratio of the first polyol and the second polyol is less than 85 wt%, the ratio of the second polyol increases, causing problems such as urethane foam deformation and reduced permanent compression set ratio, and when it exceeds 95 wt%, the ratio of the second polyol decreases, causing problems such as increased vibration transmission ratio.

[0062] In addition, based on 1 part by weight of the first polyol and second polyol mixed composition, a second reactant may be formed by including 0.01 to 0.1 part by weight of a chain extender having a hydroxyl value (OH value) of 900 to 1200 mgKOH / g.

[0063] If the proportion of the above chain extender is less than 0.01 part by weight, there is a problem of reduced tensile strength and tear strength, and if it exceeds 0.1 part by weight, the foam does not form into a consistent shape due to flow problems during foaming.

[0064] The reactant stirring step (S130) is a step of forming a polyurethane foam by stirring the first reactant and the second reactant, which are composed as described above. In the stirring step, the first reactant and the second reactant are mixed in an amount of 0.35 to 0.45 parts by weight based on 1 part by weight of the second reactant, and stirring is performed for about 3 to 10 seconds to form a polyurethane foam (100).

[0065] Based on 1 part by weight of the second reactant, when the first reactant is less than 0.30 parts by weight, the foaming speed and crosslinking time become longer, and when it exceeds 0.50 parts by weight, problems such as increased hardness and reduced moldability due to shortened curing time occur.

[0066] Figure 3 is a detailed flowchart of a mold placement step (S200) according to one embodiment of the present invention.

[0067] Figure 4 is a combination flow chart of a mold (200) according to one embodiment of the present invention.

[0068] Figure 5 is a perspective view of a combined mold (200) according to one embodiment of the present invention.

[0069] Referring to FIGS. 3 to 5, the mold placement step (S200) may be composed of a first mold placement step (S210) and a second mold placement step (S220).

[0070] First, to explain the mold (200), the mold (200) has a cross-section in the shape of the letter 'ㄷ' overall, and is a surface composed of an opening and a plurality of folded parts. The openings are attached to face each other on the inner wall of the tire, so that an internal space can be formed between the inner walls of the tire.

[0071] The first mold may have at least one fitting groove (211) on the side surface, and the second mold may have at least one protrusion (212) on the side surface.

[0072] The arrangement order of the mold (200) can be as shown in Fig. 4.

[0073] First, the first mold (210) and the second mold (220) are placed at the center of the tire.

[0074] Afterwards, a first mold placement step (S210) is performed to place a first mold (210) having a fitting groove (211) on the inner wall of the tire at regular intervals.

[0075] After the placement of the first mold is completed, a second mold (220) having a protrusion (212) is placed in the empty space between the first molds and fitted into the fitting groove (211) of the first mold to attach it to the inner wall of the tire, in a second mold placement step (S220).

[0076] The mold (200) attached to the inner wall of the tire can be provided in a form that completely surrounds the inner wall of the tire, as shown in FIG. 5, and the internal space can be provided in the form of a hollow portion penetrating both side cross-sections of the mold, so that the mold can be formed in a circular shape overall.

[0077] This type of fitting structure can be easily adapted to various tire shapes as it can be freely fixed and removed without the need for separate adhesive application.

[0078] In addition, since no adhesive is used, natural demolding is possible, which has the effect of preventing damage to the polyurethane foam (100) during demolding.

[0079] FIG. 6 is a drawing showing an injection method of a polyurethane foam injection and foaming step (S300) according to one embodiment of the present invention.

[0080] Referring to FIG. 6, the polyurethane foam injection and foaming step (S300) may inject polyurethane foam (100) through an injection port provided at a predetermined position in the mold (200).

[0081] The above injection port may be formed at one location selected from the side of the mold (200) and the inner wall of the mold (200).

[0082] It will be possible to inject polyurethane foam (100) by additionally providing a polyurethane foam injector (300) consisting of a polyurethane foam storage unit (310) and an injection nozzle (320).

[0083] A spray nozzle (320) having a bent shape is inserted into the injection port of the mold (200) to inject polyurethane foam (100) into the internal space at high speed.

[0084] At this time, the tire is fixed in one position and the polyurethane foam is injected so that it is foamed throughout the entire internal space, so that the polyurethane foam can be conveniently injected throughout the entire internal space without moving or rotating the tire member.

[0085] The injected polyurethane foam (100) is foamed into the internal space formed between the tire and the mold, filling the internal space. Since foaming occurs immediately after injection, no additional heating process is required for foaming, thereby saving production time.

[0086] In addition, since polyurethane foam is foamed only in the inner space, the entire area always has a uniform height, and a sound-absorbing material of uniform shape and quality can be obtained, which makes it easy to maintain quality during production.

[0087] In the polyurethane foam curing stage (S400), the foamed polyurethane foam is completely cured when left at room temperature for 30 seconds to 1 minute.

[0088] Figure 7 is a detailed diagram of a mold demolding step (S500) according to one embodiment of the present invention.

[0089] Referring to Fig. 7, the mold demolding step (S500) may be composed of a second mold demolding step (S510) and a first mold demolding step (S520).

[0090] After the polyurethane foam has been cured, the second mold is first demolded in the reverse order of the mold placement step (S200), and then the first mold is demolded.

[0091] When the second mold is demolded, the first mold, which was fixed and fitted with the second mold, can be demolded naturally, so the mold can be safely demolded without damaging the manufactured polyurethane foam (100).

[0092] Figure 8 is a cross-sectional view of a polyurethane foam (100) according to one embodiment of the present invention.

[0093] FIG. 9 is a cross-sectional view of a polyurethane foam (100) according to an additional embodiment of the present invention.

[0094] Referring to Figures 8 and 9, a cross-sectional view of a polyurethane foam (100) after demolding from a mold is completed. The polyurethane foam (100) may be applied in various thicknesses depending on the shape of the mold (200).

[0095] In addition, by providing additional protrusions on the inner wall of the mold, the shape of the polyurethane foam (100) can be changed, and thus, a sound-absorbing tire can be produced without delay in the production process by simply replacing the mold according to the specifications and purpose of the tire.

[0096] FIG. 10 is a perspective view of a low-noise tire (10) including a polyurethane sound-absorbing material according to one embodiment of the present invention.

[0097] Through the above polyurethane foam preparation step (S100), mold placement step (S200), polyurethane injection and foaming step (S300), polyurethane foam curing step (S400), and mold demolding step (S500), a low-noise tire including a polyurethane sound-absorbing material in the inner wall of the tire can be manufactured as shown in FIG. 10.

[0098]

[0099] Although the invention has been described with reference to specific details such as specific components and limited embodiments and drawings, these are provided only to help a more general understanding of the present invention, and the present invention is not limited to the above embodiments, and those skilled in the art to which the present invention pertains may make modifications and variations based on these descriptions.

[0100] Therefore, the idea of ​​the present invention should not be limited to the embodiments described above, and all things that are modified equally or equivalently to the following claims as well as the claims are considered to fall within the scope of the idea of ​​the present invention.

Claims

1. A method for manufacturing a low-noise tire including a polyurethane sound-absorbing material, A polyurethane foam preparation step in which a first reactant and a second reactant are mixed to prepare a polyurethane foam; A molding mold placement step of forming an internal space by attaching a first mold and a second mold that are mutually fitted to the inner wall of a tire; Polyurethane foam injection and foaming step of injecting polyurethane foam into the internal space of a mold; Polyurethane foam curing step for curing expanded polyurethane foam; Mold demolding step for demolding the mold; A method for manufacturing a low-noise tire comprising a polyurethane sound-absorbing material.

2. In paragraph 1, The above polyurethane foam preparation step is: A first reactant preparation step including an isocyanate component; A second reactant preparation step composed of a first polyol and a second polyol; A reactant stirring step for producing polyurethane foam by stirring the first and second reactants; A method for manufacturing a low-noise tire comprising a polyurethane sound-absorbing material characterized by including:

3. In paragraph 2, A method for manufacturing a low-noise tire including a polyurethane sound-absorbing material, characterized in that the first reactant is mixed in an amount of 0.35 to 0.45 parts by weight based on 1 part by weight of the second reactant.

4. In paragraph 2, The first reactant is, A method for manufacturing a low-noise tire comprising a polyurethane sound-absorbing material, characterized in that it comprises at least one selected from toluene diisocyanate, carbodiimide methylene diphenyl diisocyanate, monomeric methylene diphenyl diisocyanate, and polymeric diphenyl diisocyanate.

5. In paragraph 2, The second reactant is, The first polyol contains 85 to 95 wt% of a component having a hydroxyl value (OH Value) of 20 to 40 mgKOH / g, A method for manufacturing a low-noise tire including a polyurethane sound-absorbing material, characterized in that the second polyol is composed by mixing 5 to 15 wt% of a component having an OH value of 20 to 60 mgKOH / g.

6. In paragraph 2, The second reactant is, Based on 1 part by weight of the first polyol and second polyol mixed composition, A method for manufacturing a low-noise tire including a polyurethane sound-absorbing material, characterized in that it contains 0.01 to 0.1 weight part of a chain extender having an OH value of 900 to 1200 mgKOH / g.

7. In paragraph 1, The above molding mold is, The overall cross-section is in the shape of the letter 'ㄷ', and is a surface with an opening and multiple folds. The above opening is characterized in that it is attached facing the inner wall of the tire to form an internal space between the inner walls of the tire. A method for manufacturing a low-noise tire comprising a polyurethane sound-absorbing material.

8. In paragraph 1, The above molding mold is, A plurality of protrusions on the inner wall of the mold; A method for manufacturing a low-noise tire comprising a polyurethane sound-absorbing material characterized by further comprising:

9. In paragraph 1, The above mold placement step is, A first mold arrangement step of arranging a plurality of first molds having at least one fitting groove on a side surface at regular intervals on the inner wall of a tire; A second mold placement step of fitting a second mold having at least one protrusion on a side surface between the first molds and attaching it to the inner wall of the tire; A method for manufacturing a low-noise tire comprising a polyurethane sound-absorbing material characterized by including:

10. In paragraph 1, The above polyurethane foam injection and foaming steps are: A method for manufacturing a low-noise tire including a polyurethane sound-absorbing material (S10), characterized in that polyurethane foam is injected through an injection port provided at a predetermined position in the mold.

11. In paragraph 1, The above mold demoulding step is, Second mold demolding step for demolding the second mold; First mold demolding step for demolding the first mold; A method for manufacturing a low-noise tire comprising a polyurethane sound-absorbing material characterized by including:

12. A low-noise tire comprising a polyurethane sound-absorbing material manufactured by the method of claim 1.

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