JP5181467B2 - Pneumatic tire and manufacturing method thereof - Google Patents

Description

  The present invention relates to a pneumatic tire using a film made of a thermoplastic resin or a thermoplastic elastomer composition obtained by blending an elastomer with a thermoplastic resin as a tire component and a method for producing the same, and more specifically, a failure caused by the film. The present invention relates to a pneumatic tire and a method for manufacturing the same that are prevented to improve durability.

  In recent years, it has been proposed that a film made of a thermoplastic resin or a thermoplastic elastomer composition obtained by blending an elastomer with a thermoplastic resin is disposed on the tire inner surface as an air permeation preventive layer (see, for example, Patent Document 1 and Patent Document 2). ).

However, when such a film is used as a tire constituent member, the cut end portion is in direct contact with the surrounding hard-to-bond member, or a film harder than a normal rubber material sticks to the surrounding member. Then, those portions become a starting point of failure such as cracks, and there is a problem that the durability of the tire is lowered.
JP-A-8-217923 JP-A-11-199713

  An object of the present invention is to prevent a failure caused by a film and improve durability when using a thermoplastic resin or a film made of a thermoplastic elastomer composition obtained by blending an elastomer with a thermoplastic resin as a tire component. An object of the present invention is to provide a pneumatic tire and a manufacturing method thereof.

In order to achieve the above object, the method for producing a pneumatic tire according to the present invention uses a thermoplastic resin or a thermoplastic elastomer composition obtained by blending an elastomer with a thermoplastic resin as a tire component, and at least the width of the film. Two rubber layers are laminated so as to sandwich the film in an end region of 10 mm from the end in the width direction toward the inner side in the width direction, and an unvulcanized tire including a laminate of the film and the rubber layer is molded. The tire is vulcanized, and in the state after vulcanization, the rubber layer covers the film in the width direction while sandwiching the film from both sides .

In addition, the pneumatic tire of the present invention for achieving the above object uses, as a tire constituent member, a film made of a thermoplastic resin or a thermoplastic elastomer composition obtained by blending an elastomer with a thermoplastic resin, and at least the width direction of the film. Two rubber layers are laminated so that the film is sandwiched in an end region up to 10 mm inward in the width direction from the end, and the rubber layer sandwiches the film from both sides in a vulcanized state. It is characterized by covering the end in the width direction.

  In the present invention, when a film made of a thermoplastic resin or a thermoplastic elastomer composition is used as a tire component, a rubber layer is laminated so that the film is sandwiched between at least end regions of the film. By forming an unvulcanized tire including the laminate and vulcanizing the tire, the cut end of the film is in direct contact with the surrounding hard-to-bond member, or a film harder than a normal rubber material Prevents the surrounding members from sticking. Thereby, the failure resulting from a film can be prevented and the durability of a pneumatic tire can be improved.

  In the present invention, the average thickness Tr of each rubber layer in the end region is preferably 1.5 times or more the average thickness Tf of the film in the end region. As a real value, the average thickness Tr of each rubber layer in the end region is preferably 0.05 mm to 2.5 mm. Thereby, the edge part of a film can fully be covered with a rubber layer. On the other hand, in the pneumatic tire, the minimum thickness of the rubber layer at the end in the width direction of the film is preferably 0.03 mm to 2.0 mm in the vulcanized state.

  Moreover, it is preferable that the Mooney viscosity in the unvulcanized state of a rubber layer is 30-100. Thereby, the fluidity | liquidity in the unvulcanized state of a rubber layer is ensured, and it becomes possible to cover the edge part of a film more reliably. The Mooney viscosity is Mooney viscosity ML (1 + 4) 100 ° C. measured according to JIS K6300-1.

  Although it is necessary to laminate | stack the said rubber layer in the at least edge part area | region of a film, it is preferable to laminate | stack a rubber layer over the whole film containing this edge part area | region. Thereby, handling of the laminated body of a film and a rubber layer becomes easy.

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, wherein 1 is a tread portion, 2 is a sidewall portion, and 3 is a bead portion. A carcass layer 4 is mounted between the pair of left and right bead portions 3, 3, and an end portion of the carcass layer 4 is folded around the bead core 5 from the inside of the tire to the outside. A plurality of belt layers 6 are embedded on the outer peripheral side of the carcass layer 4 in the tread portion 1. These belt layers 6 are disposed such that the reinforcing cords are inclined with respect to the tire circumferential direction, and the reinforcing cords cross each other between the layers.

  In the pneumatic tire, a reinforcing layer 7 is disposed between the carcass layer 4 and the belt layer 6. An air permeation preventive layer 8 is disposed inside the carcass layer 4. Each of the reinforcing layer 7 and the air permeation preventing layer 8 includes a film made of a thermoplastic resin or a thermoplastic elastomer composition, and a rubber layer laminated so as to sandwich the film in at least an end region of the film. It is composed of a laminate. Here, the width direction of the film coincides with the tire axial direction at the time of tire molding. Although this embodiment demonstrates the case where the said film is used for the reinforcement layer 7 and the air permeation | blocking prevention layer 8, it is also possible to apply the said film to another tire structural member. Of course, it is also possible to apply the film to only one of the reinforcing layer 7 and the air permeation preventive layer 8.

  FIG. 2 shows a laminate of a film and a rubber layer embedded in the tire. In FIG. 2, 11 is a film, 12 is a rubber layer, and W indicates the width direction of the film 11. Two rubber layers 12 are laminated so as to sandwich the film 11 at least in an end region X from the end 11e in the width direction to 10 mm inward in the width direction. In FIG. 2, the rubber layer 12 is laminated so as to continuously extend over the entire region of the film 11 including the end region X.

  Next, the manufacturing method of the pneumatic tire mentioned above is demonstrated. FIG. 3 shows a laminate of a film and a rubber layer used as a tire constituent member, and FIG. 4 shows a state where the laminate of FIG. 3 is deformed during vulcanization. When the film 11 made of a thermoplastic resin or a thermoplastic elastomer composition is used as a tire constituent member, as shown in FIG. 3, at least an end region of the film 11 from the width direction end portion 11e to the width direction inner side up to 10 mm. Two rubber layers 12 are laminated so that the film 11 is sandwiched between X. In FIG. 3, the width of the rubber layer 12 is larger than the width of the film 11. An unvulcanized tire including a laminate of the film 11 and the rubber layer 12 obtained in this manner is formed, and the tire is vulcanized.

  In the vulcanization step, as shown in FIG. 4, the laminate of the film 11 and the rubber layer 12 is sandwiched between adjacent tire constituent members A and B, and the rubber layer 12 covers the width direction end portion 11 e of the film 11. It deforms as follows. One of the tire constituent members A and B may be a vulcanization bladder.

  The film 11 made of a thermoplastic resin or a thermoplastic elastomer composition is useful as a tire component, but its end (particularly, the cut end) is in direct contact with the surrounding hard-to-bond member, or If the end portion bumps around the surrounding members, those portions become starting points of failures such as cracks, which causes a decrease in the durability of the tire. On the other hand, by covering at least the end region X of the film 11 with the rubber layer 12, the above inconvenience can be solved and the durability of the tire can be improved.

  In the method for manufacturing a pneumatic tire, the average thickness Tr of each rubber layer 12 in the end region X is 1.5 times or more the average thickness Tf of the film 11 in the end region X, more preferably 1.5. Set to 20 to 20 times. As a real value, the average thickness Tr of each rubber layer 12 in the end region X is set in a range of 0.05 mm to 2.5 mm (see FIG. 3). Thereby, the width direction edge part 11e of the film 11 can fully be covered with the rubber layer 12. FIG. Here, if the average thickness Tr of the rubber layer 12 is too small, the covering of the end portion 11e in the width direction of the film 11 is insufficient, and conversely if too large, an unnecessarily heavy weight increase is caused.

On the other hand, in the pneumatic tire, the minimum thickness Tr _min of the rubber layer 12 at the width direction end portion 11e of the film 11 is set in a range of 0.03 mm to 2.0 mm (see FIG. 2). This minimum thickness Tr _min is the minimum value of the thickness of the rubber layer 12 measured from the width direction end portion 11e of the film 11. Thereby, the width direction edge part 11e of the film 11 can fully be covered with the rubber layer 12, and durability can be improved. Here, if the minimum thickness Tr _min of the rubber layer 12 is too small, the covering of the width direction end portion 11e of the film 11 is insufficient, and conversely, if it is too large, the weight increases more than necessary.

  In the method for manufacturing a pneumatic tire, the Mooney viscosity of the rubber layer 12 in an unvulcanized state is set in the range of 30 to 100. Thereby, the fluidity | liquidity in the unvulcanized state of the rubber layer 12 is ensured, and it becomes possible to cover the edge part 11e of the film 11 more reliably.

  In laminating the film 11 and the rubber layer 12, an adhesive may be applied between them. Further, the upper and lower rubber layers 12 sandwiching the film 11 may be different in composition, thickness, and width. The rubber layer 12 is required to be laminated on at least the end region X of the film 11, but the laminated structure is not limited to FIG. 3. For example, the laminated structure as shown in FIGS. good.

  In FIG. 5, two rubber layers 12 are laminated over the entire area of the film 11, and the widths of these rubber layers 12 are different from each other. In FIG. 6, two rubber layers 12 are laminated over the entire area of the film 11, and end portions of these rubber layers 12 are cut obliquely. In FIG. 7, two rubber layers 12 are laminated over the entire area of the film 11, and the widths of these rubber layers 12 are made to coincide with the width of the film 11. In FIG. 8, the rubber layer 12 is selectively laminated only on both ends of the film 11 so as to cover at least the end region X of the film 11. In particular, when the rubber layer 12 is laminated over the entire area of the film 11 as shown in FIGS. 3 to 5, handling of the laminate of the film 11 and the rubber layer 12 becomes easy. In other words, the film 11 alone has a thickness of 5 μm to 1000 μm and is extremely difficult to handle when it is extremely thin, particularly 500 μm or less, but it is difficult to handle by using the laminate as described above. become.

  In the pneumatic tire, when the laminate of the film 11 and the rubber layer 12 is applied to the air permeation preventive layer 8 and the rubber layer 12 is laminated over the entire area of the film 11, an effect of improving productivity is obtained. In other words, if a thermoplastic film is exposed on the tire inner surface, scratches are easily formed on the film surface when the bladder is peeled off from the tire inner surface after vulcanization. It is necessary to perform peeling. On the other hand, when the film having thermoplasticity is completely covered with the rubber layer, the above-mentioned disadvantage does not occur, so the tire cooling time in the vulcanizer is shortened and the productivity is improved. be able to.

  Below, the film used by this invention is demonstrated. This film 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 The ratio 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 embedded alone in the tire, but an adhesive layer may be laminated to improve the adhesion to the adjacent rubber. 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.

It is a meridian half section view showing a pneumatic tire according to an embodiment of the present invention. It is sectional drawing which shows the laminated body of the film embed | buried in the tire, and a rubber layer. It is sectional drawing which shows the laminated body of the film and rubber layer which are used as a tire structural member. It is sectional drawing which shows the state which the laminated body of FIG. 3 deform | transformed at the time of vulcanization. It is sectional drawing which shows the modification of the laminated body of the film and rubber layer which are used as a tire structural member. It is sectional drawing which shows the modification of the laminated body of the film and rubber layer which are used as a tire structural member. It is sectional drawing which shows the modification of the laminated body of the film and rubber layer which are used as a tire structural member. It is sectional drawing which shows the modification of the laminated body of the film and rubber layer which are used as a tire structural member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tread part 2 Side wall 3 Bead part 4 Carcass layer 5 Bead core 6 Belt layer 7 Reinforcement layer 8 Air permeation prevention layer 11 Film 11e Width direction end part 12 Rubber layer X End part area

Claims (11)

A film made of a thermoplastic resin or a thermoplastic elastomer composition obtained by blending an elastomer with a thermoplastic resin is used as a tire component, and at least an end region of the film from the end in the width direction to the inner side in the width direction is 10 mm. Two rubber layers are laminated so as to sandwich the film, an unvulcanized tire including a laminate of the film and the rubber layer is formed, the tire is vulcanized, and the rubber layer is in a state after vulcanization. A method for producing a pneumatic tire, comprising covering the width direction end of the film while sandwiching the film from both sides .   2. The pneumatic tire according to claim 1, wherein an average thickness Tr of each of the rubber layers in the end region is 1.5 times or more of an average thickness Tf of the film in the end region. Manufacturing method.   The method for manufacturing a pneumatic tire according to claim 1 or 2, wherein an average thickness Tr of each of the rubber layers in the end region is 0.05 mm to 2.5 mm.   The method for producing a pneumatic tire according to any one of claims 1 to 3, wherein the rubber layer has a Mooney viscosity in an unvulcanized state of 30 to 100.   The method for manufacturing a pneumatic tire according to any one of claims 1 to 4, wherein the rubber layer is laminated over the entire region of the film including the end region.   The pneumatic tire according to any one of claims 1 to 5, wherein when the rubber layer is laminated on the film, at least one rubber layer is disposed so as to protrude from an end in the width direction of the film. Production method.   The method for manufacturing a pneumatic tire according to claim 1, wherein the laminate is a reinforcing layer disposed between the carcass layer and the belt layer. A film made of a thermoplastic resin or a thermoplastic elastomer composition obtained by blending an elastomer with a thermoplastic resin is used as a tire component, and at least an end region of the film from the end in the width direction to the inner side in the width direction is 10 mm. Pneumatic, characterized in that two rubber layers are laminated so as to sandwich the film, and in a vulcanized state, the rubber layer covers the end of the film in the width direction while sandwiching the film from both sides tire.   The pneumatic tire according to claim 8, wherein a minimum thickness of the rubber layer at a width direction end of the film is 0.03 mm to 2.0 mm in a vulcanized state.   The pneumatic tire according to claim 8 or 9, wherein the rubber layer is laminated over the entire region of the film including the end region.   The pneumatic tire according to any one of claims 8 to 10, wherein the laminate is a reinforcing layer disposed between a carcass layer and a belt layer.

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