阅读说明：本技术 包括密封剂层以及吸音材料层的轮胎 (Tire comprising sealant layer and sound absorbing material layer ) 是由 卢奎东 徐炳镐 金正宪 于 2021-04-12 设计创作，主要内容包括：本发明涉及一种包括密封剂层以及吸音材料层的轮胎,包括：吸音材料层,位于轮胎内侧；密封剂层,位于轮胎内侧面与吸音材料层之间,涂布到轮胎内侧面；以及,薄膜层,位于吸音材料层与密封剂层之间。上述轮胎可以利用涂布到轮胎内侧面上的密封剂层在发生扎胎时实现自密封,还可以通过包括吸音材料而具有降噪性能,而且即使是在钉子透过轮胎以及密封剂而达到吸音材料的情况下也可以防止吸音材料的微小碎片导致密封剂功能的降低并维持降噪性能。(The present invention relates to a tire including a sealant layer and a sound absorbing material layer, comprising: a sound absorbing material layer located inside the tire; a sealant layer disposed between the inner side surface of the tire and the sound absorbing material layer and applied to the inner side surface of the tire; and a thin film layer between the sound absorbing material layer and the sealant layer. The tire can realize self-sealing when puncture occurs by using the sealant layer coated on the inner side surface of the tire, has noise reduction performance by including the sound absorbing material, and can prevent the reduction of the function of the sealant caused by the tiny fragments of the sound absorbing material and maintain the noise reduction performance even if the nail penetrates through the tire and the sealant to reach the sound absorbing material.)

1. A tire, comprising:

a sound absorbing material layer located inside the tire;

a sealant layer disposed between the inner tire surface and the sound absorbing material layer and applied to the inner tire surface; and the number of the first and second groups,

a thin film layer located between the sound-absorbing material layer and the sealant layer;

wherein the sound-absorbing material layer includes a 1 st porous material having an average pore size of 1,200 to 2,400. mu.m.

2. The tire of claim 1, wherein:

the sound absorbing material layer further includes a 2 nd porous material laminated on the 1 st porous material,

one side surface of the 1 st porous material is adhered to the tire inner surface through the sealant layer, and the 2 nd porous material is laminated on the other side surface of the 1 st porous material.

3. The tire of claim 2, wherein:

the average pore size of the above-mentioned 2 nd porous material is 100 μm to 1,200. mu.m.

4. The tire of claim 2, wherein:

the density of the 1 st porous material is 25kg/m³To 40kg/m³A hardness of 10 to 20kgf and a tensile strength of 0.8kgf/cm²Above, the elongation is above 70%,

the density of the 2 nd porous material is 20kg/m³To 40kg/m³A hardness of 10 to 20kgf and a tensile strength of 0.8kgf/cm²Above, the elongation is 70% or more.

5. The tire of claim 2, wherein:

the thickness of the sound-absorbing material layer is 20mm to 60mm,

the thickness of the 1 st porous material is 30 to 90% of the entire thickness of the sound absorbing material layer.

6. The tire of claim 1, wherein:

the film layer may include Polyurethane (PU) or Thermoplastic Polyurethane (TPU).

7. The tire of claim 1, wherein:

the thickness of the film layer is 0.01mm to 5 mm.

Technical Field

The present invention relates to a tire including a sealant layer and a sound absorbing material layer, and more particularly, to a tire which can be self-sealed when a puncture occurs and has noise reduction performance.

Background

When the conventional pneumatic tire is punctured due to foreign matters on the road surface, the safety and stability of the conventional pneumatic tire in the process of quick driving can be reduced, and even a human-life accident can happen. In order to solve the above-mentioned conventional problems, a tire has been developed which can prevent air leakage by immediately sealing a punctured portion with a special sealing material inside a tire even when the tire is punctured during running by applying the special sealing material inside a general tire, thereby enabling continuous running.

Meanwhile, along with the strengthening of government regulations related to automobile noise and the increase in demand for electric vehicles, the demand for noise reduction performance of tires is also increasing. However, in recent tire development trends, Ultra High Performance (UHP) tires, in which a tread portion of the tire in contact with a road surface is wide and a sidewall (side wall) corresponding to a side surface of the tire has a relatively low flatness, have attracted attention.

The structural characteristics of the tire as described above cause an increase in the rigidity of the sidewall, and therefore, the impact transmitted from the road surface cannot be effectively damped (damming) in the structure of the tire itself, and as a result, the sound pressure rise associated with the noise induction is finally caused. Further, air vibration may be generated in the interior (cavity) of the tire and noise may be transmitted to the interior of the vehicle, which may result in a reduction in the driver's comfort during driving (hereinafter, noise due to air vibration is collectively referred to as resonance sound). Therefore, tire manufacturers have introduced tires in which noise generated inside the tire is reduced by using a foam (sound absorbing material) made of a polyurethane material having open pores formed therein.

However, unlike a general tire, since a polymer substance is coated inside a self-sealing tire, when a sound absorbing material capable of reducing the internal noise of the tire is attached to the upper portion of the polymer substance, the self-sealing function cannot be achieved due to the sharp decrease of the sealing performance to the punctured portion.

Further, when the sound absorbing material is attached to another portion, particularly, when the sound absorbing material is attached to a sidewall portion, there is a problem that the sound absorbing material may be damaged due to interference with the coupling of the tire and the hub. Further, when the sound absorbing material is mounted on the hub, the sound absorbing material may not function properly due to a significant reduction in noise reduction performance.

Disclosure of Invention

The present invention has been made to solve the problems of the prior art, and an object of the present invention is to provide a tire which can achieve self-sealing by a sealant layer applied to an inner surface of the tire when a puncture occurs, has resonance sound reduction performance by including a sound absorbing material, and can maintain noise reduction performance while preventing a reduction in the function of a sealant due to minute fragments of the sound absorbing material even when a nail penetrates the tire and the sealant to reach the sound absorbing material.

In order to achieve the above object, the present invention provides a tire comprising: a sound absorbing material layer located inside the tire; a sealant layer disposed between the inner tire surface and the sound absorbing material layer and applied to the inner tire surface; and a thin film layer between the sound absorbing material layer and the sealant layer; wherein the sound-absorbing material layer includes a 1 st porous material having an average pore size of 1,200 to 2,400. mu.m.

The sound absorbing material layer may further include a 2 nd porous material laminated on an upper side of the 1 st porous material, one side surface of the 1 st porous material may be adhered to the inner surface of the tire by the sealant layer, and the 2 nd porous material may be laminated on the other side surface of the 1 st porous material.

The average pore size of the above-mentioned 2 nd porous material may be 100 μm to 1,200. mu.m.

The density of the 1 st porous material may be 25kg/m³To 40kg/m³The hardness may be 10 to 20kgf, and the tensile strength may be 0.8kgf/cm²The elongation may be 70% or more, and the density of the 2 nd porous material may be 20kg/m³To 40kg/m³The hardness may be 10 to 20kgf, and the tensile strength may be 0.8kgf/cm²The elongation may be 70% or more.

The sound-absorbing material layer may have a thickness of 20mm to 60mm, and the 1 st porous material may have a thickness of 30% to 90% of the entire thickness of the sound-absorbing material layer.

The film layer may include Polyurethane (PU) or Thermoplastic Polyurethane (TPU), and the thickness of the film layer may be 0.01mm to 5 mm.

The tire to which the present invention is applied can be self-sealed by the sealant layer applied to the inner surface of the tire when the tire is punctured, can have noise reduction performance by including the sound absorbing material, and can maintain the noise reduction performance while preventing the reduction of the function of the sealant due to the minute fragments of the sound absorbing material even when the sound absorbing material is reached by the nail penetrating the tire and the sealant.

Drawings

Fig. 1 is a cut oblique view of a pneumatic tire to which an embodiment of the present invention is applied.

Fig. 2 is a cut oblique view of a pneumatic tire to which another embodiment of the present invention is applied.

[ notation ] to show

1: tyre for vehicle wheels

2: sealant layer

3: sound absorbing material layer

31: 1 st porous material

32: 2 nd porous material

4: film layer

Detailed Description

Next, in order that those having ordinary knowledge in the art to which the present invention pertains can easily carry out the present invention, embodiments to which the present invention is applied will be described in detail with reference to the accompanying drawings. However, the present invention can be realized in various forms, and is not limited to the embodiments and drawings described herein.

The present invention can simultaneously exert two properties by combining the above two technologies.

First, since a special polymer material is coated on an inner liner portion of a tire as a sealant (sealant), when a tire is punctured due to a nail or a sharp foreign object, the punctured portion can be sealed by using special polymer material dysentery and air leakage can be prevented, and thus, a vehicle does not need to be stopped on a road shoulder during driving and the tire can be replaced.

Secondly, the silent (silent) tire is provided with a foaming body, namely a porous material with a plurality of air holes, so that resonance generated by resonance when the air layer in the tire receives vibration generated on the road surface during running can be reduced.

At present, the automobile industry is developing rapidly, and not only electric automobiles but also automatic driving automobiles appear. In particular, in automobiles of this concept, both of the above-described technologies must be provided. This is because the vehicle interior of the electric vehicle does not have an internal combustion engine and does not generate engine noise of the vehicle, and thus the sound of tire rolling or other noise becomes relatively large.

However, in order to achieve both of the above-described performances at the same time, there are the following problems. That is, since a general sound absorbing material is manufactured by Foaming (Foaming) a material such as polyurethane, many fine pores are densely distributed. When the sound-absorbing material is adhered to the upper side of the sealant layer applied to the inner liner of the tire, the sound-absorbing material layer is reached when a foreign object such as a nail penetrates the tire, and minute pieces of the sound-absorbing material are detached together with the nail due to the viscous property of the sealant layer when the nail is pulled out, and the minute pieces of the sound-absorbing material cause a problem that the sealing ability of the sealant layer is lowered, or the sound-absorbing material layer having minute air holes densely formed on the upper side of the sealant layer and the upper sealant layer are physically and tightly bonded to each other, thereby lowering the fluidity of the sealant and further lowering the function of the sealant.

In order to solve the above-described problems, when the sound-absorbing material layer is disposed at a position other than the position of the inner liner where the sealant layer is not applied or wound around the hub, there is a possibility that the sound-absorbing performance of the sound-absorbing material is significantly lowered, and the mounting of the tire on the hub type is hindered, which may induce problems in terms of use.

Further, although the sound absorbing material may be disposed above the sealant, the size of the pores of the sound absorbing material may be increased to prevent the flow of the sealant from being hindered and to prevent air pores from being formed by the porous participating material. In this case, although the self-sealing performance of the sealant in a stationary state can be greatly improved, the sealant flows into the large pores of the sound absorbing material due to the centrifugal force generated in the tire during running due to the increase in the size of the pores, thereby again causing a problem in that the self-sealing function is deteriorated.

To this end, a tire to which the present invention is applied includes: a sound absorbing material layer adhered to the inner side surface of the tire; the sealant is positioned between the inner side surface of the tire and the sound absorption material layer; and a thin film layer between the sound absorbing material layer and the sealant layer.

Fig. 1 is a cut oblique view of a pneumatic tire to which an embodiment of the present invention is applied.

With reference to fig. 1, a tyre 1 to which the invention is applicable comprises: a sound absorbing material layer 3 located inside the tire 1; a sealant layer 2 disposed between the inner surface of the tire 1 and the sound absorbing material layer 3 and applied to the inner surface of the tire 1; and a film layer 4 between the sound absorbing material layer 3 and the sealant layer 2.

Sealant layer 2 is applied to the inner side of tire 1, and in the case where the inner side of tire 1 includes an inner liner, sealant layer 2 may be generally located on the upper side of the inner liner. In the description of the present invention, when the 2 nd layer is described as being positioned on the upper side of the 1 st layer with respect to each layer positioned on the inner side surface of the tire 1, the 1 st layer is positioned closer to the inner side surface of the tire 1 than the 2 nd layer, and the 2 nd layer is positioned on the other side surface of the one side surface facing the inner side surface of the tire 1 of the 1 st layer.

The sealant layer 2 may be applied to a part or the entire inner surface of the tire 1, and preferably may be applied only to the inner surface corresponding to the ground contact surface of the tire 1. This is because the portion of the tire 1 penetrated by foreign matter is mainly concentrated on the ground contact surface of the tire 1. Therefore, the width of the sealant layer 2 may be 100 to 120 length% with respect to the width of the tread portion of the tire 1.

Further, the thickness of the sealant layer 2 may be 2mm to 8 mm. When the thickness of the sealant layer 2 is within the above range, it is possible to reliably self-seal a puncture due to a nail, a projection, or the like, without affecting the flow characteristics of the sealant.

The sealant layer 2 may be produced by a crosslinking reaction using a sealant composition containing a rubber component, or may be produced by a non-crosslinking reaction using a sealant composition containing a crosslinked rubber component. The sealant composition is not particularly limited as long as it has adhesiveness, and a general rubber composition used for sealing a punctured tire of the tire 1 can be used.

Among them, as an example of the sealant composition, a sealant composition containing a butyl-based rubber as a main component, and a sealant composition containing a natural rubber-based compound, a silicone-based compound, a urethane-based compound, a styrene-based compound, or an ethylene-based compound may be used.

As the butyl-based rubber, butyl rubber (IIT), halogenated butyl rubber (X-IIR) such as brominated butyl rubber (Br-IIR) and chlorinated butyl rubber (Cl-IIR), and the like can be used.

The sealant composition may further contain, as a rubber component, diene rubbers such as Natural Rubber (NR), Isoprene Rubber (IR), Butadiene Rubber (BR), Styrene Butadiene Rubber (SBR), styrene-isoprene-butadiene rubber (SIBR), ethylene propylene diene monomer rubber (EPDM), Chloroprene Rubber (CR), and Nitrile Butadiene Rubber (NBR). However, in view of flowability and the like, the content of the butyl rubber is preferably 90% by weight or more based on 100% by weight of the rubber component.

The sealant composition may also include polyisobutylene, which may have a weight average molecular weight of 1,000 to 10,000 g/mol. Further, the polyisobutylene may be contained in an amount of 100 to 500 parts by weight with respect to 100 parts by weight of the rubber component. When the content of the polyisobutylene is less than 100 parts by weight, the fluidity of the material may be lowered, and when it exceeds 500 parts by weight, the morphological stability of the material may be lowered.

In addition, the sealant composition may further include a liquid polymer. The liquid polymer may be, for example, liquid polybutene, liquid polyisobutylene, liquid polyisoprene, liquid polybutadiene, liquid polyalphaolefin, liquid isobutylene, liquid ethylene alpha-olefin copolymer, liquid ethylene propylene copolymer, liquid ethylene butene copolymer, and the like. The liquid polymer may be included by 50 parts by weight to 1,000 parts by weight, specifically 150 parts by weight to 500 parts by weight, with respect to 100 parts by weight of the rubber component. When the content of the liquid polymer is less than 50 parts by weight, the problem of lowering the fluidity of the material may be caused, and when it exceeds 1,000 parts by weight, the problem of lowering the morphological stability of the material may be caused.

The sealant composition may further include an inorganic additive. The inorganic additive is used for adjusting the reinforcing property of the sealant composition, and may be selected from the group consisting of carbon black, silica, calcium carbonate, calcium silicate, magnesium oxide, alumina, barium sulfate, talc, mica, and mixtures thereof. At this time, the inorganic additive may be contained in an amount of 10 to 100 parts by weight, preferably 30 to 60 parts by weight, based on 100 parts by weight of the rubber component.

The sealant composition may further comprise an additive selected from the group consisting of a vulcanizing agent, a vulcanization accelerator aid, a binder, and a mixture thereof.

The vulcanizing agent is used to assist crosslinking of the sealant composition, and may be contained in an amount of 1 to 20 parts by weight, preferably 5 to 10 parts by weight, relative to 100 parts by weight of the rubber component.

As the vulcanizing agent, for example, sulfur-based vulcanizing agents, organic peroxides, bismaleimides, benzoquinone derivatives, phenol-based vulcanizing agents, and oxidized metal oxides such as magnesium oxide can be used. As the sulfur-based vulcanizing agent, inorganic vulcanizing agents such as powdered sulfur (S), insoluble sulfur (S), precipitated sulfur (S), and colloidal sulfur (sulfur) can be used.

As the vulcanization accelerator for accelerating vulcanization, any one selected from the group consisting of sulfenamides, thiazoles, thiurams, thioureas, guanidines, dithiocarbamates, aldamines, imidazolines, xanthines, and combinations thereof can be used. At this time, the vulcanization accelerator may be contained in an amount of 0 to 10 parts by weight, preferably 3 to 5 parts by weight, relative to 100 parts by weight of the rubber component.

The vulcanization accelerator is a compounding agent which improves the accelerating action of the vulcanization accelerator by being used in combination with the vulcanization accelerator, and zinc oxide and stearic acid may be used together. In the case of using zinc oxide and stearic acid together, 1 to 5 parts by weight and 0.5 to 3 parts by weight may be contained, respectively, with respect to 100 parts by weight of the rubber component in order to exert an appropriate action as a vulcanization-accelerating assistant.

As the adhesive for improving the adhesive force of the sealant composition, natural resins such as phenol resins, rosin (rosin) resins, terpene (terpene) resins, and the like, and synthetic resins such as petroleum resins, coal tar (coal tar), alkylphenol resins, and the like can be used. At this time, the adhesive may be included by 0 to 10 parts by weight, preferably 3 to 5 parts by weight, with respect to 100 parts by weight of the rubber component.

Further, the sound absorbing material layer 3 is for reducing resonance noise generated in the inner space of the tire 1, and the sound absorbing material layer 3 may be in a sheet shape elongated in the circumferential direction of the tire 1. That is, the sound absorbing material layer 3 is formed in a sheet shape, extends in the circumferential direction of the tire 1, and can be formed in a ring shape like the tire 1 by joining both side ends thereof to each other.

Further, the sound-absorbing material layer 3 may have a thickness of 20mm to 60mm, specifically, 30mm to 60mm, and a width of 10% to 120% with respect to the width of the tread portion of the tire 1. When the thickness of the sound-absorbing material layer 3 is less than 35mm, there is a possibility that the noise reduction performance is deteriorated, and when it exceeds 60mm, there is a possibility that the sound-absorbing material is worn due to friction with the rim surface facing the sound-absorbing material inside the tire 1 during running.

The attracting material layer 3 includes a 1 st porous material 31 having an average pore size of 1,200 μm to 2,400 μm.

That is, the average pore size of the 1 st porous material 31 is larger than that of a porous material currently used as a sound absorbing material, so that the specific surface area between the sealant layer 2 and the sound absorbing material layer 3 is reduced to improve the fluidity of the sealant, and even when foreign matter such as nails penetrates the tire 1 and the sealant layer 2 to reach the sound absorbing material layer 3, the specific surface area of adhesion between the surfaces of the nails and the 1 st porous material 31 is reduced to prevent the 1 st porous material 31 from being broken into fine pieces to reduce the function of the sealant and maintain the proper performance.

When the average pore size of the 1 st porous material 31 is less than 1,200. mu.m, the fluidity of the sealing agent contacting the surface may be lowered, and when it exceeds 2,400. mu.m, the durability of the sound absorbing material may be lowered during driving.

The porous material may be any one selected from the group consisting of a porous nonwoven fabric, a porous foam (form), and a laminate thereof.

Specifically, the porous nonwoven fabric may be a polyester nonwoven fabric or a polystyrene nonwoven fabric, and the porous foam may be an ether-type polyurethane foam which is a polyurethane foam using a polyether polyol as a raw material, an ester-type polyurethane foam which is a polyurethane foam using a polyester polyol as a raw material, an ether/ester-type polyurethane foam which is a polyurethane foam using a polyester polyether polyol as a raw material, a synthetic resin foam such as a polyethylene foam, and a rubber foam such as an ethylene propylene rubber foam (EPDM foam) or a nitrile rubber foam (NBR foam).

The polyurethane foam can be usually produced by a polyurethane reaction of a polyisocyanate compound (polyisocyanate compound) and a polyol (hydroxyl compound).

The sound absorbing material layer 3 may further include a 2 nd porous material 32 laminated to an upper side of the 1 st porous material 31.

Fig. 2 is a cut perspective view of a pneumatic tire to which another embodiment of the present invention is applied, illustrating a case where a 2 nd porous material 32 is further included.

Referring to fig. 2, one side surface of the 1 st porous material 31 is adhered to the inner side surface of the tire 1 through the sealant layer 2, and the 2 nd porous material 32 is laminated on the other side surface of the 1 st porous material 31.

The 2 nd porous material 32 may have an average pore size of 100 to 1,200 μm, and specifically, 300 to 1,000 μm.

That is, the average pore size of the 2 nd porous material 32 is smaller than the average pore size of the 2 nd porous material 31. That is, since the average pore size of the 1 st porous material 31 is relatively larger than that of the 2 nd porous material 32, it is possible to help reduce noise while minimizing the inhibition of fluidity of the sealant layer 2, and since the average pore size of the 2 nd porous material 32 is relatively smaller than that of the 1 st porous material 31, it is possible to achieve more excellent noise reduction performance than the 1 st porous material 31.

At this time, the thickness of the 1 st porous material 31 may be 10 to 100% of the entire thickness of the sound-absorbing material layer 3, and specifically, may be 30 to 90% of the length. In the case where the thickness of the 1 st porous material 31 is less than 10% of the entire thickness of the sound-absorbing material layer 3, the self-sealing performance may be deteriorated due to movement of minute sound-absorbing material pieces when the nail is pulled out after the inserted nail reaches the 2 nd porous material 32, and in the case where the length exceeds 100%, the noise reduction performance may be deteriorated as compared with the case where the length is 100% or less.

Further, the density of the 1 st porous material 31 may be 25kg/m³To 40kg/m³The hardness may be 10 to 20kgf, and the tensile strength may be 0.8kgf/cm²Above, the elongation can be above 70%,

the density of the first porous material 31 is less than 25kg/m³In the case of (2), the durability may be lowered, and the amount of the organic solvent may exceed 40kg/m³In this case, the weight of the sound absorbing material may be increased to affect the tire performance. When the hardness of the 1 st porous material 31 is less than 10kgf or more than 20kgf, the engineering property may be deteriorated. The tensile strength of the porous material 31 at the 1 st position is less than 0.8kgf/cm²In the case of (1), the durability may be reduced, and in the case of the elongation of the porous material 31 being less than 70%, the durability may be reduced.

The density of the 2 nd porous material 32 may be 20kg/m³To 40kg/m³The hardness may be 10 to 20kgf, and the tensile strength may be 0.8kgf/cm²Above, the elongation can be above 70%,

the density of the second porous material 32 is less than 20kg/m³In the case of (2), the durability may be lowered, and the amount of the organic solvent may exceed 40kg/m³In this case, the tire performance may be affected by the increase in weight. When the hardness of the 2 nd porous material 32 is less than 10kgf or more than 20kgf, the engineering property may be deteriorated. The tensile strength of the second porous material 32 is less than 0.8kgf/cm²In the case of (2), there is a possibility that the durability is lowered, and in the case that the elongation of the 2 nd porous material 32 is less than 70%, there is a possibility that the elongation is less than 70%Resulting in a decrease in durability.

The 1 st porous material 31 and the 2 nd porous material 32 may be adhered by various methods. As an example, the 2 nd porous material 32 may be adhered to the upper side of the 1 st porous material 31 by an adhesive or a double-sided tape, or the like.

The 2 nd porous material 32 is different only in the average pore size, density, etc., and the description about the material thereof, etc. is the same as the 1 st porous material 31, so a repetitive description thereof will be omitted herein.

Further, the tire 1 may further include a film layer 4 between the sound absorbing material layer 3 and the sealant layer 2. The thin film layer 4 can prevent the sealant from penetrating into the pores of the sound absorbing material layer 3 and blocking the pores by separating the sound absorbing material layer 3 and the sealant layer 2, thereby preventing the sound absorbing performance of the sound absorbing material layer 3 from being lowered, and also preventing the problem of the sealing performance of the sealant layer 2 from being lowered due to the minute fragments of the porous material mixed into the sealant.

For the purpose described above, the film layer 4 may be formed of polyurethane, specifically, thermoplastic polyurethane (tppu). When the film layer 4 is formed of thermoplastic polyurethane, it is advantageous in improving the flowability of the sealant.

The thickness of the film layer 4 may be 0.01mm to 5mm, specifically, 0.02mm to 0.05 mm. In the case where the thickness of the film layer 4 is less than 0.01mm, there may be a problem in that the film effect cannot be normally exerted because the sealant penetrates the film layer, and in the case where it exceeds 5mm, there may be a problem in that the price of auxiliary materials increases and a problem in that the Rotation Resistance (RRC) performance decreases due to an increase in the inner weight of the tire.

As described above, the present invention can maintain the noise performance by forming the sound absorbing material layer 3 in two layers and applying a porous material having the same pore size as that of the prior art in the upper layer toward the outside of the tire, and reduce the specific surface area between the sealant layer 2 and the sound absorbing material layer 3 by increasing the pores of the porous material in the lower layer in contact with the sealant layer 2 and thereby improve the fluidity of the sealant layer 2. With this, even when the nail penetrates the tire 1 and the sealant layer 2 to reach the sound absorbing material layer 3, the adhesion specific surface area between the surface of the nail and the sound absorbing material layer 3 can be reduced, thereby preventing the problem of the deterioration of the function of the sealant layer 2 due to the minute fragments of the porous material.

However, if a porous material having relatively larger pores than those of the conventional ones is disposed in the lower layer of the porous material in contact with the sealant layer 2 as described above, the sealant material may flow into the pores of the porous material due to the centrifugal force generated during the running process and the compression and release of the porous material, and eventually the sealant material may infiltrate into the pores of the porous material. In short, the fluidity of the sealant layer 2 is hindered and the sealant material cannot seal the puncture site.

Therefore, the present invention is configured to prevent a problem that a sealant material flows into pores of the sound absorbing material layer 3 during running of the tire 1 by disposing the sound absorbing material layer 3 under the sealant layer 2 and applying the thin film layer 4 on the sound absorbing material layer 3 released from the sealant layer 2 as in the conventional method, thereby improving fluidity of the sealant layer 2 and maintaining the original function of the sealant layer 2 even when a nail penetrates the tire 1, the sealant layer 2 and the thin film layer 4 to reach the sound absorbing material layer 3.

Next, in order to facilitate easy implementation of the present invention by those having ordinary knowledge in the art to which the present invention pertains, embodiments to which the present invention is applied will be described in detail. However, the present invention can be realized in various forms, and is not limited to the embodiments described herein.

[ production example: manufacture of tires

A 1 st porous material and a 2 nd porous material having physical properties shown in table 1 below were prepared.

[ TABLE 1 ]

	Unit of	2 nd porous material	1 st porous material
				Density of	kg/m3	28.8	29.5
Hardness (ILD 25%)	kgf	12.46	17.7
				Tensile strength	kgf/cm2	1.31	0.96
Elongation percentage	％	248.5	83.29
				Average pore size	μm	750	1850

-hardness: JIS K6400-2

-tensile strength, elongation: JIS K6400-5

-density: JIS K7222

Further, a sealant composition was prepared by mixing 100 parts by weight of butyl rubber, 400 parts by weight of polyisobutylene, 40 parts by weight of a carbon black additive, and 2 parts by weight of a sulfur-based vulcanizing agent, and applied to the inner surface of a tire of 195/65R15 standard, and then a porous material was adhered thereto as shown in table 2 below, thereby producing a tire.

In table 2 below, comparative example 1 is a case where the sound absorbing material layer is not included, reference example 1 is a case where the sound absorbing material layer is formed by adhering the 2 nd porous material with an adhesive after adhering a Thermoplastic Polyurethane (TPU) film having a thickness of 0.04mm to the sealant layer, reference example 2 is a case where the sound absorbing material layer is formed by adhering and laminating the 2 nd porous material to the upper side of the 1 st porous material with an adhesive after adhering the 1 st porous material to the sealant layer, and example 1 is a case where the sound absorbing material layer is formed by adhering and laminating the 1 st porous material and the 2 nd porous material with an adhesive after adhering a thermoplastic polyurethane TPU film having a thickness of 0.04mm to the sealant layer.

At this time, the sound absorbing material layers of the comparative example, the reference example, and the example were the same in overall thickness.

[ TABLE 2 ]

[ test example: determination of tire Properties ]

For the manufactured tire, the sealing effect, the high-speed durability test, and the adhesion durability test were performed, and the results thereof are shown in table 3 below.

[ TABLE 3 ]

Noise test: the resonance sound inside the tire was measured by the variation in the magnitude of the vertical force on the tire/hub center axis when passing the protrusion at a constant interval using a protrusion passing (clean impact) test apparatus (protrusion passing test apparatus: a tester for measuring the vibration response and vibration attenuation of the suspension when the tire or the combination of the tire and the suspension receives the impact of the protrusion).

-sealing effect: in order to confirm the self-sealing performance of the tire, a total of 30 nails, each of 10 specially manufactured small (2.5 mm in body diameter), medium (3.4 mm in body diameter) and large (5.0 mm in body diameter), were inserted into the tread portion coated with the sealant inside the tire. After being left at room temperature or stored in a high-temperature and low-temperature chamber for 12 hours under various conditions, the stored tires were taken out and the nails were removed, and then the sealed state was confirmed with soapy water. The case of no air leakage equal to the initial air pressure was described as 100%.

High speed and adhesion durability test: after a test was performed for 34 hours in such a manner that the vehicle was decelerated to 100km/h and re-accelerated from a high-speed running state of 240km/h in a certain repeated cycle, the adhesion of the sound-absorbing material layer and the maintenance of the shape were confirmed by the naked eye.

As can be seen from table 3, in the case of example 1, compared with the comparative examples and the reference examples, the sealing effect is improved at normal temperature, low temperature and high temperature, and the noise reduction effect is excellent.

While the preferred embodiments to which the present invention is applied have been described in detail in the foregoing, the scope of the claims of the present invention is not limited thereto, and various modifications and improvements made by the workers skilled in the art using the basic concepts of the present invention defined in the appended claims are also within the scope of the claims of the present invention.