JP2012030505A - Method of manufacturing pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing pneumatic tire allowing efficient manufacture of a pneumatic tire with a high-strength partition wall on its inner surface.SOLUTION: A green tire T' with the partition wall L1 projecting from its inner surface disposed on an inner liner member L serving as an innermost surface member of the pneumatic tire T is vulcanized by a bladder-less vulcanizer not having a vulcanizing bladder for pressing the inner liner member L from the inside of the tire. Particularly, the partition wall L1 projecting from its inner surface is formed on the inner liner member L, the inner liner member L with the partition wall L1 is used as the vulcanizing bladder, and the green tire T' is vulcanized in a state that the inner liner member L is expanded by a pressing medium M within the green tire T to mold the pneumatic tire T with the inner liner member L integrated with its inner surface, and thereafter, an unnecessary part of the inner liner member L that projects from a bead part of the pneumatic tire T is cut off.

Description

  The present invention relates to a method for manufacturing a pneumatic tire, and more particularly, to a method for manufacturing a pneumatic tire that can efficiently manufacture a pneumatic tire having a high-strength partition wall on the inner surface of the tire.

  Road noise is noise that is generated when a pneumatic tire picks up road surface irregularities and propagates through the axle to the passenger compartment and resonates in the passenger compartment. The frequency of such road noise is in the range of 50 Hz to 400 Hz, and it is known that the noise in the vicinity of 250 Hz is generated by vibration of air filled in the tire cavity due to cavity resonance.

  As a measure for reducing the cavity resonance vibration of the pneumatic tire as described above, it has been proposed to provide a partition wall on the tire inner surface (see, for example, Patent Documents 1 and 2). On the other hand, in the conventional tire vulcanization method, a bladder is arranged inside the green tire put in the mold of the vulcanizer, and vulcanization is performed in a state where the bladder is filled with high-pressure gas. Therefore, the tire inner surface is formed to be substantially flat. Therefore, in the conventional tire vulcanization method using the vulcanization bladder, it is extremely difficult to form the partition wall on the tire inner surface in the vulcanization process.

  Therefore, it is necessary to attach such a partition wall to a vulcanized tire later, but in that case, the manufacturing cost of the pneumatic tire increases due to an increase in work steps, and the partition wall attached after vulcanization is bonded. There is a problem of insufficient strength.

JP-A-5-294102 JP 2005-28897 A

  An object of the present invention is to provide a method of manufacturing a pneumatic tire that enables efficient manufacture of a pneumatic tire having a high-strength partition wall on the inner surface of the tire.

  In order to achieve the above object, a method for manufacturing a pneumatic tire according to the present invention includes: a green tire provided with a partition wall protruding from an inner liner member serving as an innermost surface member of the pneumatic tire; Vulcanization is performed by a bladderless vulcanizing apparatus that does not have a vulcanizing bladder that is pressed from above.

  More specifically, the manufacturing method of the pneumatic tire of the present invention for achieving the above object includes forming a partition wall protruding from the inner surface of the inner liner member that is the innermost surface member of the pneumatic tire, and including the partition wall. The inner liner member is integrated into the inner surface by vulcanizing the green tire with the inner liner member inflated with a pressure medium inside the green tire using the inner liner member as a vulcanization bladder. The formed pneumatic tire is molded, and then an unnecessary portion of the inner liner member protruding from the bead portion of the pneumatic tire is cut off.

  In the present invention, a pneumatic tire is provided with a partition wall for reducing cavity resonance vibration by previously providing a partition wall on the inner surface of the inner liner member of the green tire and vulcanizing the green tire with a bladderless vulcanizer. Can be efficiently manufactured. In addition, by integrally forming the partition wall with respect to the inner liner member before vulcanization, it is possible to form a partition wall having higher bonding strength than when bonding after vulcanization.

  A partition wall protruding from the inner surface of the inner liner member that is the innermost surface member of the pneumatic tire is formed, and the inner liner member including the partition wall is used as a vulcanization bladder, and the inner liner is pressed by a pressure medium inside the green tire. When a pneumatic tire in which the inner liner member is integrated on the inner surface is formed by vulcanizing the green tire in a state where the member is inflated, the sealability of the pressurized medium filled in the tire is sufficiently ensured. Bladderless vulcanization can be carried out. After vulcanization, unnecessary portions of the inner liner member protruding from the bead portion of the pneumatic tire are removed, so that the inner liner member protruding from the bead portion does not adversely affect the tire performance.

  In the present invention, it is preferable to integrally mold the inner liner member having the partition walls by press molding. As a result, the bonding strength between the partition wall and the inner liner member can be increased, and the inner liner member provided with the partition wall can be efficiently molded.

  As a constituent material of the inner liner member and the partition wall, a rubber composition containing butyl rubber as a main component can be used. In this case, since the materials of the partition walls and the inner liner member undergo a crosslinking reaction during vulcanization, the bonding strength between them can be sufficiently ensured. Moreover, as a constituent material of an inner liner member and a partition, a thermoplastic resin or a thermoplastic elastomer composition can be used. In this case, the inner liner member provided with the partition can be easily formed by press molding.

1 is a perspective sectional view showing a pneumatic tire according to an embodiment of the present invention. It is a perspective view which shows the shaping | molding apparatus of the inner liner member provided with the partition used for the pneumatic tire of FIG. It is a perspective sectional view showing the pneumatic tire which consists of other embodiments of the present invention. It is a perspective view which shows the shaping | molding apparatus of the inner liner member provided with the partition used for the pneumatic tire of FIG. It is principal part sectional drawing which shows the vulcanization | cure apparatus of the pneumatic tire which consists of embodiment of this invention. The manufacturing method of the pneumatic tire which consists of embodiment of this invention is shown, (a)-(d) is sectional drawing in each process.

  Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows a pneumatic tire according to an embodiment of the present invention, and FIG. 2 shows an apparatus for forming an inner liner member having a partition wall used in the pneumatic tire of FIG. As shown in FIG. 1, in the pneumatic tire T, a plurality of plate-like partition walls L <b> 1 protruding toward the inner side in the tire radial direction are spaced in the tire circumferential direction on the inner surface of the inner liner member L that is the innermost surface member. Is formed. These partition walls L1 are installed in order to reduce the cavity resonance vibration of the pneumatic tire T, but may be installed for other purposes.

  The inner liner member L provided with such a partition L1 can be integrally formed by, for example, press molding. That is, as shown in FIG. 2, a plurality of slits 2 corresponding to the partition walls L <b> 1 are formed in the press table 1 along the supply path of the inner liner member L. On the other hand, a molding blade 3 is disposed above each slit 2 so as to be movable up and down, and the molding blade 3 is inserted into the slit 2. Therefore, after supplying the inner liner member L to the press stand 1, the inner liner member L having a plurality of partition walls L1 arranged intermittently in the tire circumferential direction is formed by pushing the forming blade 3 into the slit 2. can do.

  FIG. 3 shows a pneumatic tire according to another embodiment of the present invention, and FIG. 4 shows an apparatus for forming an inner liner member having a partition wall used in the pneumatic tire of FIG. As shown in FIG. 3, in the pneumatic tire T, an inner liner member L, which is the innermost surface member, is formed on the inner surface so that a partition wall L1 ′ protruding toward the inner side in the tire radial direction meanders in the tire circumferential direction. ing. The partition wall L1 'is installed to reduce the cavity resonance vibration of the pneumatic tire T, but may be installed for other purposes.

  The inner liner member L provided with such a partition L1 'can be integrally formed by, for example, press molding. That is, as shown in FIG. 4, a slit 2 'corresponding to the partition L1' is formed along the supply path of the inner liner member L in the press table 1 '. On the other hand, a molding blade 3 ′ is disposed above each slit 2 ′ so as to be movable up and down, and the molding blade 3 ′ is inserted into the slit 2 ′. Therefore, after supplying the inner liner member L to the press stand 1 ′, the inner liner provided with one partition wall L1 ′ extending continuously in the tire circumferential direction by pushing the forming blade 3 ′ into the slit 2 ′. The member L can be molded.

  A green tire provided with a partition wall L1 (or L1 ′) protruding from the inner liner member L serving as the innermost surface member of the pneumatic tire T is provided with a vulcanization bladder that presses the inner liner member L from the inside of the tire. When vulcanized by the vulcanizer, the partition L1 (or L1 ′) protruding from the inner surface of the inner liner member L is crushed. Therefore, a green tire provided with a partition wall L1 (or L1 ′) protruding from the inner liner member L serving as the innermost surface member of the pneumatic tire T is provided with a vulcanizing bladder that presses the inner liner member L from the inside of the tire. Vulcanization is done with a bladderless vulcanizer.

  FIG. 5 shows a vulcanizing apparatus for a pneumatic tire according to an embodiment of the present invention. As shown in FIG. 5, the vulcanizing apparatus includes a mold 11 that molds the outer surface of the pneumatic tire T, and an upper and lower gripping the inner liner member L that is the innermost surface member of the pneumatic tire T as a vulcanizing bladder. A pair of clamp members 21 and 22, a heating means (not shown) for heating the mold 11, and a pressure medium supply means (not shown) for supplying the pressure medium M to the inner liner member L are provided. As the heating means and the pressurized medium supply means, those used in a normal vulcanizer can be employed.

  The mold 11 includes a plurality of sectors 12 for forming a tread portion of the pneumatic tire T, a lower side plate 13 and an upper side plate 14 for forming a sidewall portion of the pneumatic tire T, and a bead of the pneumatic tire T. It comprises a lower bead ring 15 and an upper bead ring 16 that form the part.

  The lower clamp member 21 includes a lower bead ring 15 and a lower clamp ring 23. The lower clamp ring 23 is disposed at a position radially inward of the lower bead portion of the pneumatic tire T. The lower clamp ring 23 is configured to be movable in the vertical direction. The outer peripheral end of the lower clamp ring 23 is engaged with the inner peripheral end of the lower bead ring 15, and the lower end portion of the inner liner member L processed into a cylindrical shape is sandwiched in the gap.

  On the other hand, the upper clamp member 22 includes an upper clamp ring 24 and an auxiliary clamp ring 25. The upper clamp ring 24 is disposed above the lower clamp ring 23 and at a position radially inward of the upper bead portion of the pneumatic tire T. The upper clamp ring 24 is configured to be movable in the vertical direction, and the auxiliary clamp ring 25 is configured to be detachable from the upper clamp ring 24. The outer peripheral end of the upper clamp ring 24 is engaged with the inner peripheral end of the auxiliary clamp ring 25, and the upper end portion of the inner liner member L processed into a cylindrical shape is sandwiched in the gap. Further, the outer peripheral end of the auxiliary clamp ring 25 is engaged with the inner peripheral end of the upper bead ring 16.

  FIGS. 6A to 6D show a method for manufacturing a pneumatic tire according to an embodiment of the present invention. First, as shown to Fig.6 (a), the lower end part and upper end part of the inner liner member L processed into the cylindrical shape are each hold | gripped with the clamp members 21 and 22. FIG. At this time, the joint on the circumference of the inner liner member L is configured to ensure airtightness. The partition wall L1 is disposed on the radially inner side of the cylindrical inner liner member L. Thereby, the inner liner member L can be used as a vulcanization bladder. The inner liner member L provided with the partition wall L1 can be formed into a seamless cylindrical body. On the other hand, a green tire T ′ is disposed outside the inner liner member L in the radial direction. The green tire T ′ is not provided with an inner liner member. However, when importance is attached to air permeation prevention performance, an inner liner member can be provided in advance on the green tire T ′.

  Next, as shown in FIG. 6B, a heated low pressure medium M is introduced inside the inner liner member L, and the inner liner member L is applied inside the green tire T ′ by the pressure medium M. Inflated. Thereby, shaping of the green tire T ′ is performed. The internal pressure in the shaping process is preferably set in the range of 5 kPa to 50 kPa. In the shaping process, the inner liner member L, which is thinner than the conventional vulcanization bladder, can be flexibly deformed and does not strongly press the bead portion of the green tire T ′ unlike the conventional vulcanization bladder. Air can be effectively discharged from between the green tire T ′ and the inner liner member L. It is also possible to provide a plurality of holes penetrating in the thickness direction in the green tire T ′ and discharge air between the inner liner member L and the green tire T ′ through these holes. In this case, the vulcanization failure due to the air remaining between the green tire T ′ and the inner liner member L can be more reliably reduced.

  Next, as shown in FIG. 6C, after the mold 11 is closed, the heated high-pressure medium M is introduced into the inner liner member L, and the green tire T ′ is vulcanized. . The internal pressure in the vulcanization process is preferably set in the range of 1.0 MPa to 2.5 MPa. In the closed mold state, since the mold 11 receives pressure, there is no problem even if the rigidity of the inner liner member L is low. And the pneumatic tire T with which the inner liner member L was integrated by the inner surface is obtained by completing a vulcanization process.

  Next, as shown in FIG. 6D, the inner liner member L is integrated with the inner surface by releasing the mold 11 and releasing the grip of the inner liner member L by the clamp members 21 and 22. The pneumatic tire T is removed from the vulcanizer. Thereafter, unnecessary portions of the inner liner member L protruding from the bead portion of the pneumatic tire T are appropriately cut off. The unnecessary portion of the inner liner member L may be removed while the clamp members 21 and 22 are holding the inner liner member L.

  According to the method for manufacturing a pneumatic tire described above, a partition wall L1 is provided in advance on the inner surface of the inner liner member L of the green tire T ′, and the green tire T ′ is vulcanized by a bladderless vulcanizing device, thereby A pneumatic tire provided with the partition wall L1 for reducing resonance vibration can be efficiently manufactured. Further, by integrally forming the partition wall L1 with respect to the inner liner member L before vulcanization, the partition wall L1 having a higher bonding strength can be formed as compared with the case of bonding after vulcanization.

  In particular, the inner liner member L of the pneumatic tire T is used as a vulcanization bladder, and the inner liner member is vulcanized while the inner liner member L is inflated inside the green tire T ′. When the pneumatic tire T in which L is integrated on the inner surface is molded, the sealing property of the pressurized medium M filled in the green tire T ′ can be sufficiently secured, and bladderless vulcanization can be performed without any problem. .

  As a constituent material of the inner liner member L, a rubber composition containing butyl rubber as a main component can be used. When using the inner liner member L made of such a rubber composition, the inner liner member L may be in an unvulcanized state or may be vulcanized. In this case, since the materials of the partition wall L1 and the inner liner member L undergo a crosslinking reaction during vulcanization, it is possible to sufficiently secure the bonding strength between them. Moreover, as a constituent material of the inner liner member L, a thermoplastic resin or a thermoplastic elastomer composition can be used. In this case, the inner liner member L provided with the partition wall L1 can be easily formed by press molding.

  In the above-described embodiment, the case where the vulcanizing apparatus in which the pair of upper and lower clamp members 21 and 22 holding the inner liner member L as a vulcanizing bladder is used has been described. In the present invention, the structure of the vulcanizing apparatus is used. Is not particularly limited. For example, a vulcanizing device in which a shaping unit for shaping a green tire is configured to be detachable and at least the shaping process is performed outside may be used. In this case, the clamp member that holds the inner liner member L may be mounted on the shaping unit. In addition, a green tire T ′ having a partition wall L1 on the inner surface of the inner liner member L is formed in advance, and a green tire T ′ is obtained by a bladderless vulcanizing apparatus that does not have a vulcanization bladder that presses the inner liner member L from the tire inner side. It is also possible to vulcanize.

  Hereinafter, the thermoplastic resin or the thermoplastic elastomer composition used as a constituent member of the inner liner member will be described. This inner liner member can be composed of a thermoplastic resin or a thermoplastic elastomer composition obtained by blending an elastomer in a thermoplastic resin.

  Examples of the thermoplastic resin used in the present invention include polyamide resins [for example, nylon 6 (N6), nylon 66 (N66), nylon 46 (N46), nylon 11 (N11), nylon 12 (N12), nylon 610 (N610), nylon 612 (N612), nylon 6/66 copolymer (N6 / 66), nylon 6/66/610 copolymer (N6 / 66/610), nylon MXD6, nylon 6T, nylon 6 / 6T copolymer, nylon 66 / PP copolymer, nylon 66 / PPS copolymer], polyester resin [for example, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyethylene isophthalate (PEI), polybutylene terephthalate / Tetramethylene glycol copolymer, PET PEI copolymer, polyarylate (PAR), polybutylene naphthalate (PBN), liquid crystal polyester, aromatic polyester such as polyoxyalkylene diimide diacid / polybutylene terephthalate copolymer], polynitrile resin [for example, polyacrylonitrile ( PAN), polymethacrylonitrile, acrylonitrile / styrene copolymer (AS), methacrylonitrile / styrene copolymer, methacrylonitrile / styrene / butadiene copolymer], poly (meth) acrylate resin [eg polymethacryl Acid methyl (PMMA), polyethyl methacrylate, ethylene ethyl acrylate copolymer (EEA), ethylene acrylic acid copolymer (EAA), ethylene methyl acrylate resin (EMA)], polyvinyl resin [for example, vinyl acetate (EVA), polyvinyl alcohol (PVA), vinyl alcohol / ethylene copolymer (EVOH), polyvinylidene chloride (PVDC), polyvinyl chloride (PVC), vinyl chloride / vinylidene chloride copolymer, vinylidene chloride / methyl acrylate Copolymer], cellulose resin [eg, cellulose acetate, cellulose acetate butyrate], fluorine resin [eg, polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), polychlorofluoroethylene (PCTFE), tetrafluoroethylene / ethylene Copolymer (ETFE)], imide resin [for example, aromatic polyimide (PI)] and the like.

  Examples of the elastomer used in the present invention include diene rubbers and hydrogenated products thereof [for example, NR, IR, epoxidized natural rubber, SBR, BR (high cis BR and low cis BR), NBR, hydrogenated NBR, Hydrogenated SBR], olefin rubber [eg ethylene propylene rubber (EPDM, EPM), maleic acid modified ethylene propylene rubber (M-EPM)], butyl rubber (IIR), isobutylene and aromatic vinyl or diene monomer copolymer, Acrylic rubber (ACM), ionomer, halogen-containing rubber [for example, Br-IIR, Cl-IIR, brominated product of isobutylene paramethylstyrene copolymer (Br-IPMS), chloroprene rubber (CR), hydrin rubber (CHC, CHR), Chlorosulfonated polyethylene (CSM), chlorinated polyethylene (CM), maleic acid-modified chlorinated polyethylene (M-CM)], silicone rubber (eg, methyl vinyl silicone rubber, dimethyl silicone rubber, methyl phenyl vinyl silicone rubber), sulfur-containing rubber (eg, polysulfide rubber), fluoro rubber (eg, Vinylidene fluoride rubber, fluorine-containing vinyl ether rubber, tetrafluoroethylene-propylene rubber, fluorine-containing silicone rubber, fluorine-containing phosphazene rubber), thermoplastic elastomer (eg, styrene elastomer, olefin elastomer, polyester elastomer, And urethane elastomers and polyamide elastomers).

  In the thermoplastic elastomer composition used in the present invention, the composition ratio of the thermoplastic resin component (A) and the elastomer component (B) may be appropriately determined depending on the balance of film thickness and flexibility, but the preferred range is 10/90 to 90/10, more preferably 20/80 to 85/15 (weight ratio).

  In the thermoplastic elastomer composition according to the present invention, in addition to the essential components (A) and (B), as a third component, other polymers such as a compatibilizer and a compounding agent can be mixed. The purpose of mixing other polymers is to improve the compatibility between the thermoplastic resin component and the elastomer component, to improve the film molding processability of the material, to improve heat resistance, to reduce costs, etc. Examples of the material used for this include polyethylene, polypropylene, polystyrene, ABS, SBS, and polycarbonate.

The thermoplastic elastomer composition is prepared by melt-kneading a thermoplastic resin and an elastomer (unvulcanized material in the case of rubber) in advance using a twin-screw kneading extruder or the like, and adding an elastomer component in the thermoplastic resin forming a continuous phase. It is obtained by dispersing. When the elastomer component is vulcanized, a vulcanizing agent may be added under kneading to dynamically vulcanize the elastomer. Further, various compounding agents (excluding the vulcanizing agent) to the thermoplastic resin or the elastomer component may be added during the kneading, but are preferably mixed in advance before kneading. The kneading machine used for kneading the thermoplastic resin and the elastomer is not particularly limited, and examples thereof include a screw extruder, a kneader, a Banbury mixer, and a biaxial kneading extruder. Among these, it is preferable to use a twin-screw kneading extruder for kneading the resin component and the rubber component and for dynamic vulcanization of the rubber component. Further, two or more types of kneaders may be used and kneaded sequentially. As conditions for melt-kneading, the temperature may be higher than the temperature at which the thermoplastic resin melts. The shear rate during kneading is preferably 2500 to 7500 sec ⁻¹ . The entire kneading time is from 30 seconds to 10 minutes, and when a vulcanizing agent is added, the vulcanization time after addition is preferably from 15 seconds to 5 minutes. The thermoplastic elastomer composition produced by the above method is formed into a film by molding with a resin extruder or calender molding. The method for forming a film may be a method of forming a film of a normal thermoplastic resin or thermoplastic elastomer.

  The thin film of the thermoplastic elastomer composition thus obtained has a structure in which the elastomer is dispersed as a discontinuous phase in a thermoplastic resin matrix. By adopting the dispersion structure in such a state, it is possible to set the Young's modulus in a range of 1 to 500 MPa and to impart appropriate rigidity as a tire constituent member.

  The thermoplastic resin or thermoplastic elastomer composition can be molded into a sheet or film and used alone as a tire component, but an adhesive layer is laminated in order to improve the adhesion to adjacent rubber. Also good. Specific examples of the adhesive polymer constituting the adhesive layer include ultrahigh molecular weight polyethylene (UHMWPE), ethylene ethyl acrylate copolymer (EEA), ethylene methyl acrylate resin (EMA) having a molecular weight of 1 million or more, preferably 3 million or more. ), Acrylate copolymers such as ethylene acrylic acid copolymer (EAA) and their maleic anhydride adducts, polypropylene (PP) and its maleic acid modification, ethylene propylene copolymer and its maleic acid modification, Polybutadiene resin and its modified maleic anhydride, styrene-butadiene-styrene copolymer (SBS), styrene-ethylene-butadiene-styrene copolymer (SEBS), fluorine thermoplastic resin, polyester thermoplastic resin, etc. Can be mentioned. These can be extruded into a sheet form or a film form by a conventional method, for example, using a resin extruder. The thickness of the adhesive layer is not particularly limited, but it is preferable that the thickness is small for weight reduction of the tire, and 5 μm to 150 μm is preferable.

DESCRIPTION OF SYMBOLS 1 Press stand 2 Slit 3 Molding blade 11 Mold 21 Lower clamp member 22 Upper clamp member L Inner liner member L1 Partition M Pressure medium T Pneumatic tire T 'Green tire

Claims (5)

  Vulcanizing a green tire provided with a partition wall protruding from the inner liner member, which is the innermost surface member of the pneumatic tire, with a bladderless vulcanizer that does not have a vulcanization bladder that presses the inner liner member from the inside of the tire. A method of manufacturing a pneumatic tire characterized by the above.   A partition wall protruding from the inner surface of the inner liner member, which is the innermost surface member of the pneumatic tire, is formed, and the inner liner member provided with the partition wall is used as a vulcanization bladder. The green tire is vulcanized in a state where the liner member is inflated to form a pneumatic tire in which the inner liner member is integrated on the inner surface, and then the inner portion protruding from the bead portion of the pneumatic tire. A method for manufacturing a pneumatic tire, comprising cutting off an unnecessary portion of a liner member.   The method for manufacturing a pneumatic tire according to claim 1 or 2, wherein the inner liner member including the partition wall is integrally formed by press molding.   A rubber composition mainly composed of butyl rubber is used as a constituent material of the inner liner member and the partition wall, and the materials of the partition wall and the inner liner member are subjected to a crosslinking reaction during vulcanization of the green tire. The manufacturing method of the pneumatic tire in any one of claim | item 1-3.   The method for manufacturing a pneumatic tire according to any one of claims 1 to 3, wherein a thermoplastic resin or a thermoplastic elastomer composition is used as a constituent material of the inner liner member and the partition wall.

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