WO2007075062A1

WO2007075062A1 - Tire not necessary to fill up with air

Info

Publication number: WO2007075062A1
Application number: PCT/KR2006/005829
Authority: WO
Inventors: Soung Ho Lee
Original assignee: Jihan Co., Ltd
Priority date: 2005-12-29
Filing date: 2006-12-28
Publication date: 2007-07-05

Abstract

The present invention relates to a tire not needing air filling. Common tires except for tires military use or special use comprises a tread as the outermost layer, a carcass layer, so-called belt, under the tread and a special rubber layer as a inner liner layer. Such multilayered structure of the tire is for absorption of impact applied to the tire, prevention of air leakage from the inside of the tire and better contact with the road surface. However, the tire with this structure is mainly made of rubber and thus should be exchanged after a predetermined time has passed due to aging and abrasion of the rubber. Also, when the tire punctured, fatal accidents can occur at a high speed. Therefore, various tires which are not flattened when it is punctured have been developed. According to the present invention, the tire comprises a tread part having an air layer in the tread part and a carcass layer supplemented by nano-silicate and metal nanoparticles for providing color and abrasion resistance, and an aerogel layer. Therefore, when the tread part is severely damaged the tire can be protected from puncture. Also, the tread part has considerably improved durability by addition of nano-silicate and it is possible to provide a color tire with various colors.

Description

Description TIRE NOT NECESSARY TO FILL UP WITH AIR

Technical Field

[1] The present invention relates to a tire which does not need to be filled up with air, and more particularly, a tire comprising a tread part in contact with the road surface having a rubber layer supplemented with nano- silicate and metal nanoparticles and an aerogel layer having 98% or more of air layer.

[2]

Background Art

[3] Korean Design Application No. 1999-21176 discloses a puncture free, in which foamed soft rubber is filled in the space where air is filled otherwise, whereby it is used like an air tube. According to this application, the large amount of air contained in pores of the foamed rubber absorbs the impact applied on the surface of thetire. That is, in this tire, the foamed soft rubber takes the place of the air filling part. However, there is described only a simple structure of the tire without description of elasticity of proper foamed rubbers according to weight and speed of vehicles. Cars can have a weight up to several hundreds tones. Therefore, in order to sufficiently absorb the energy generated when the tire contacts with the road surface, the foamed rubber should have a considerably high strength. However, when the foam layer has such elastic strength, various noises and impact energy generated when the car contacts the road surface are delivered to the body of the car and thus, the boarding comfortableness is considerably deteriorated.

[4] In another manner, Korean Patent Laid-Open No. 1997-77914 discloses a tire having a sub-tire mounted in the tire for moving for a predetermined distance with the sub-tire when the tire is punctured. However, this tire is only for traveling up to a predetermined distance but does not solve the problem of puncture.

[5]

Disclosure of Invention

Technical Problem

[6] The nano-silicate used in the tread part according to the present invention is an elastomer/polymer nanocomposite comprising a silicate in the layered structure including the smectite group such as montmrillonite, and hectorite supplemented with polymer/rubber composite.

[7] Also, according to the present invention, the elastomer/polymer nanocomposite is combined with metal nanoparticles upon the formation of the tread so that the polymer rubber and the metal nanoparticles are bonded to each other to improve mechanical and chemical properties.

[8] The aerogel used according to the present invention is a superporous material prepared by drying wet gel, which is synthesized by the sol-gel reaction, under supercritical conditions and the like, where the gas-liquid interface does not exist, without contraction so that the nano pore structure is maintained. When the wet gel is prepared by the sol-gel reaction, it is necessary to dry off the solvent contained in the gel structure. In the general drying process, the liquid and the vapor coexist in the pores of the gel and a meniscus is formed at the gas-liquid interface by the surface tension. A great capillary pressure occurs at the gas-liquid interface in the pore. Since this force acts on a very small area where the wet pore wall meets with the meniscus, the gel may contract and the original structure may be destroyed. Therefore, if the gel is dried by removing the solvent under supercritical conditions above the critical temperature and critical pressure, where the gas-liquid interface does not exist, the structure of the wet gel can be maintained. The aerogel thus-obtained has a superporous structure, showing various unique properties.

[9] It is a material mainly comprising silicon dioxide and has a structure having SiO2 fibers of a micrometer diameter which are sparsely tangled and air molecules filling the space between the fibers, in which the air is 98% of the total volume.

[10] Now, the preparation process according to the present invention is described.

[11] The elastomer nanocomposite used as the tread according to the present invention is prepared as follows.

[12] According to the present invention, the montmorillonite has Si4+ substituted with

A13+ which has a lower valent in the silica layer of the tetrahedron structure and has A13+ with mainly Fe2+ and Me2+ and a small amount of Na+, H+, K+ in the gypscite layer of the octahedron structure, in which the divalent cations has stronger bonding to the silicate layer and thereby weaker ion exchanging effect, as compared to monovalent cations, whereby it shows a lower swelling property upon contact with water.

[13] The method for intercalating a polymer between clay layers includes (1) intercalation of polymers or prepolymers from solution, (2) in situ intercalative polymerization) and (3) melt intercalation method. It is not particularly limited but properly selected according to chemical properties of rubbers to be intercalated between the layers or properties of the final product.

[14] According to the present invention, the cations between the clay layers are substituted with ammonium ion, a quartervalent ion having a long alkyl chain, or phosphonium ion.

[15] The cations such as Na+ exposed on the clay surface is treated with alkyl ammonium since it has excellent hydrophilic properties but repulses the polymer rubber molecules.

[16]

Brief Description of the Drawings [17] Further objects and advantages of the invention can be more fully understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

[18] FIG. 1 is a cross-sectional view of a conventional tire; and [19] FIG. 2 is a cross-sectional view of the tire according to the present invention. [20]

Best Mode for Carrying Out the Invention

[21] Example 1 [22] 2Dsodium montmrillonite (Kunimine, Japan) was put into 2OL of distilled water and mechanically stirred for 24 hours or more while kept at a temperature of 80 to 9O⁰C. NBR latex (acrylo nitril 34%, Hyundai Petrochemistry) and zinc nanoparticles were added thereto to 10 wt% based on the total weight and stirred for 3 hours at 60 to 7O⁰C. Then, diluted dichloroacetacid solution (0.00 IM) was added to the mixture to coagulate latex. The coagulated latex was collected, washed with distilled water and dried in an oven kept at 100⁰C or below. The resulting product was pounded homogeneously using a roll mill and placed in a thermal forming machine at 16O⁰C to form a sheet of about 5D/D.

[23] The prepared sheet was formed into a tire using a conventional tire forming machine and vulcanized to give a tire tread.

[24] [25] Example 2 [26] Except for using 5 wt% of montmrillonite, the procedures same to those of Example 1 were performed to prepare a tire tread.

[27] [28] Comparative Example 1 [29] Except for using 10 wt% of carbon black, instead of montmrillonite, the procedures same to those of Example 1 were performed to prepare a tire tread.

[30] Physical properties of the tires prepared according to the above-described examples are shown in the following table. [31] Table 1

[32] ^Modulus was measured by Young s modulus. [33] From the result shown in the table, it was noted that the hardness and elastic modulus were increased by the nano-treated montmrillonite. However, the Comparative Example 1, in which only the carbon black was added without montmrillonite, showed increased hardness but decreased elastic modulus.

[34] Therefore, according to the present invention, it was possible to attain supplement of tire strength and increase of tire durability by the increase of strength and elasticity. [35] The tire employing the tire tread as described above has the composition as shown in FIG. 1. [36] The tire comprises a tread part 1 having prominences and depressions as the outermost part, a belt layer 2 and a carcass layer 5 between a air filled part A and the belt layer and is assembled in a ring shape at the outside of a rim 3.

[37] The tread part is a part coming in direct contact with the road surface and should have a elasticity, a durability suitable and strength for that. The tread part closely comes in contact with the carcass layer by the medium of the belt layer. The air filled part A maintains the ring shape structure by the carcass layer 5 to prevent deformation since it is filled with strong air pressure. This conventional tire has the tread part, the belt layer and carcass layer which are made of different materials. Therefore, they should be formed in a determined sequence and thus, the preparation process becomes long. Also, when the air tightness of the air filling part is damaged, there may occur very serious safety accidents.

[38] The tire according to the present invention comprises a tread part made of a polymer nanocomposite around a rim 10 and an aerogel layer 15 therein, as shown in FIG. 2.

[39] The tire according to the present invention is prepared by forming the tread part and filling the aerogel therein. That is, it is not formed with different materials for the tread, belt and carcass unlike the conventional tire. Therefore, it can be prepared in a simple process and has the problem of flat tire dissolved.

[40] Also, according to the present invention, it is possible to prepare a tire having a desired color by adding proper colorant or pigment since carbon black is not added for supplement of the tire unlike the conventional tire.

[41]

Industrial Applicability [42] The present invention relates to a tire not necessary for air filling. The tire comprises a tread part having an air layer in the tread part and a carcass layer supplemented by nano-silicate and metal nanoparticles for providing color and abrasion resistance, and an aerogel layer. Therefore, when the tread part is severely damaged, the tire can be protected from puncture. Also, the tread part has considerably improved durability by addition of nano-silicate and it is possible to provide a color tire with various colors.

[43]

[44]

Claims

[1] A tire not needing air filling prepared by the steps of: adding montmrillonite in distilled water, mechanically stirring the mixture at a temperature of 80 to 9O⁰C for 24 hours or more, adding rubber latex and zinc nanoparticles in the amount of 10 wt% based of the total weight, stirring at 60 to

70⁰C for 3 hours and naturalizing the mixture by a weak acid, followed by washing with distilled water and drying to prepare powdered polymer silicate nanocomposite; forming the polymer silicate nanocomposite prepared in the above step into a sheet; forming the sheet into a tire using a common tire forming machine, followed by vulcanization to prepare a tire tread; and filling aerogel into the inside of the tread. [2] A tire comprising a tire tread part assembled in the ring shape around a rim and an aerogel layer inside the tire tread part, in which the tire tread part is prepared by the steps of: adding montmrillonite in distilled water, mechanically stirring the mixture at a temperature of 80 to 90⁰C for 24 hours or more, adding rubber latex and zinc nanoparticles in the amount of 10 wt% based of the total weight, stirring at 60 to

7O⁰C for 3 hours and naturalizing the mixture by a weak acid, followed by washing with distilled water and drying to prepare powdered polymer silicate nanocomposite; forming the polymer silicate nanocomposite prepared in the above step into a sheet; forming the sheet into a tire using a common tire forming machine, followed by vulcanization to prepare a tire tread; and filling aerogel into the inside of the tread.