JP3946048B2 - Pneumatic tire manufacturing method and pneumatic tire - Google Patents

Description

【００５３】
これらタイヤについて、テストドライバーにより走行試験を行い、ドライ路面での走行フィーリング、ウエット路面での走行フィーリング、ウエット路面での走行タイム、ドライ路面での走行タイムを評価し、その結果を表２に示した。走行フィーリングは３．０を基準とし、数値が大きいほどフィーリングが良好であることを意味する。走行タイムは基準タイヤを１００とする指数にて示したものであり、数値が小さいほど走行タイムは短いことを意味する。
【００５４】
【表２】

【００５５】
この表２から判るように、本発明タイヤ１〜３はいずれも基準タイヤに比べて走行フィーリングが良好であり、しかもウエット路面での走行性能が優れていた。特に、高分子フィルム層を備えた本発明タイヤ１〜２は、ウエット路面での走行性能のみならずドライ路面での走行性能も向上していた。
【００５６】
次に、タイヤサイズ２１５／４５ＺＲ１７の空気入りタイヤについて、図３（ａ）〜（ｄ）の手順に基づいて本発明タイヤ４〜６を得た。また、グリーンタイヤに変形加工を施さない通常の手順に基づいて基準タイヤを得た。そのタイヤ仕様を表３に示す。表３において、グリーンタイヤの平均トレッドラジアス及びベルトドラムの湾曲ラジアスは、モールドの平均トレッドラジアスを１００とする指数にて示したものである。
【００５７】
【表３】

【００５８】
これらタイヤについて、テストドライバーにより走行試験を行い、ウエット路面での走行フィーリング、高速耐久性を評価し、その結果を表４に示した。走行フィーリングは３．０を基準とし、数値が大きいほどフィーリングが良好であることを意味する。高速耐久性は基準タイヤを１００とする指数にて示したものであり、数値が大きいほど耐久性が良好であることを意味する。
【００５９】
【表４】

【００６０】
この表４から判るように、本発明タイヤ４〜６はいずれも基準タイヤに比べて走行フィーリングが良好であり、しかも高速耐久性が優れていた。
【００６５】
【発明の効果】
以上説明したように本発明によれば、左右一対のビードコア間にカーカス層を装架してなる筒状のボディー部をトロイダル状にインフレートして、複数のベルト層を含む環状のトレッド部の内周面に圧着することでグリーンタイヤを組み立てた後、該グリーンタイヤのトレッド部をタイヤ全周にわたって該トレッド部の横断面のラジアスより小さいラジアスを有する中子でタイヤ内側から押圧して該トレッド部の形状をタイヤ外側に凸とし、その変形させたグリーンタイヤをモールド内に挿入して加硫を行うようにしたから、加硫後のカーカスコードの残留歪を均一化し、タイヤ走行性能を向上することができる。
【図面の簡単な説明】
【図１】本発明で得ようとする空気入りタイヤの一例を示すタイヤ子午線半断面図である。
【図２】本発明の第１実施形態からなる空気入りタイヤの製造方法を示し、（ａ）はグリーンタイヤの組み立て工程を示す断面図、（ｂ）はグリーンタイヤの変形工程を示す断面図、（ｃ）は加硫工程を示す半断面図である。
【図３】本発明の第２実施形態からなる空気入りタイヤの製造方法を示し、（ａ）はトレッド部の成形工程を示す断面図、（ｂ）はグリーンタイヤの組み立て工程を示す断面図、（ｃ）はグリーンタイヤの変形工程を示す断面図、（ｄ）は加硫工程を示す半断面図である。
【符号の説明】
１ トレッド領域
２ サイドウォール領域
３ ビード領域
４ ビードコア
５ カーカス層
６ ベルト層
７ 高分子フィルム層
８ トレッドゴム
１１ 中子
１２ ベルト成形ドラム
１２ａ 湾曲部
Ｘ ボディー部
Ｙ トレッド部
Ｔ グリーンタイヤ
Ｍ モールド[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a pneumatic tire and a pneumatic tire obtained therefrom, and more particularly to a method for manufacturing a pneumatic tire and a pneumatic tire in which residual strain of a carcass cord is made uniform.
[0002]
[Prior art]
Generally, when manufacturing a pneumatic tire, an inner liner layer and a carcass layer are sequentially wound around a band forming drum in a cylindrical shape, and then bead cores are set on both ends of the carcass layer, and both ends of the carcass layer are placed around the bead core. The body part is formed by winding the left and right side wall rubbers in a cylindrical shape, while the belt layers are wound around the belt forming drum sequentially in a cylindrical shape to form multiple belt layers, and then the tread rubber is wound in an annular shape. To form the tread part.
[0003]
Next, after the body portion is transferred to the shaping drum, the tread portion is transferred to the outer peripheral side of the body portion. The body portion is inflated in a toroidal shape and pressed onto the inner peripheral surface of the tread portion to form a green tire. In the vulcanization process, the green tire is pressure-bonded to the inner surface of the mold by a high internal pressure bladder and vulcanized.
[0004]
However, in the green tire molded as described above, the tread portion and the side portion start to be deformed after completion, and eventually become concave or substantially flat on the inside of the tire. For this reason, when the green tire is inserted into the mold and vulcanized in this state, the residual strain of the carcass cord is not constant and changes depending on the portion of the tire. And this reduces the tire running performance.
[0005]
[Problems to be solved by the invention]
An object of the present invention is to provide a method for manufacturing a pneumatic tire and a pneumatic tire that can make the residual distortion of the carcass cord uniform and improve the tire running performance.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, a method for manufacturing a pneumatic tire according to the present invention includes a plurality of belt layers in which a cylindrical body portion formed by mounting a carcass layer between a pair of left and right bead cores is inflated in a toroidal shape. After assembling the green tire by pressure bonding to the inner peripheral surface of the annular tread portion including the tire, the tread portion of the green tire is spread over the entire tire circumference. A core having a radius smaller than the radius of the cross section of the tread portion. The tire is pressed from the inside of the tire so that the shape of the tread portion is convex toward the outside of the tire, and the deformed green tire is inserted into a mold for vulcanization.
[0007]
Thus, the residual strain of the carcass cord after vulcanization can be made uniform by changing the shape of the green tire so that the shape of the tread portion protrudes outward from the tire before vulcanization. As a result, it is possible to greatly improve the tire running performance, particularly on a wet road surface.
[0008]
As a method of making the shape of the tread portion convex toward the tire outer side in the state of the green tire, the following (1) to ( 2 It is preferable to employ any one of the methods.
[0009]
(1) After assembling the green tire, the tread portion of the green tire is pressed from the inside of the tire with a core having a radius smaller than the radius of the cross section of the tread portion over the entire circumference of the tire to change the shape of the tread portion to the tire. Convex outward.
[0010]
(2) Using a belt forming drum having a convex curved portion on the outer peripheral surface, a plurality of belt layers and a tread rubber are formed on the outer peripheral side of the belt forming drum and laminated to form an annular tread portion. Then, after assembling a green tire by inflating a cylindrical body part formed by mounting a carcass layer between a pair of left and right bead cores in a toroidal shape and crimping to the inner peripheral surface of the tread part, The tread portion of the green tire is pressed from the inside of the tire with a core having a radius smaller than the radius of the cross section of the tread portion over the entire circumference of the tire to make the shape of the tread portion convex toward the outside of the tire.
[0012]
When the green tire deformed as described above is inserted into the mold and vulcanized, the lift rate of the green tire in the vulcanization process with respect to the mold is -1.0 to 3.0% at the tread center portion. The shoulder portion preferably has a content of 1.0 to 5.0%. In particular, the lift rate at the shoulder portion is preferably larger than the lift rate at the tread center portion. In this way, while making the lift rate at the tread center part relatively small, the lift rate at the shoulder part is made relatively large so that the residual strain of the carcass cord after vulcanization is more effectively uniformized. can do. The lift rate is an increase rate of the inner diameter of the mold with respect to the outer diameter of the green tire.
[0013]
Further, the average tread radius of the green tire is preferably 50 to 100% of the average tread radius of the mold. Thereby, the residual distortion of the carcass cord after vulcanization can be more effectively uniformized.
[0014]
Furthermore, it is preferable to perform the deformation work after forming the green tire in an atmosphere of 50 to 100 ° C., and cool it in that state to stabilize the shape of the green tire. That is, the deformation of the green tire is easy in a high temperature atmosphere that does not cause vulcanization, and the shape can be stabilized by cooling the green tire as it is after the deformation.
[0015]
In the present invention, a polymer film layer having a thickness of 0.05 to 0.5 mm and a Young's modulus at 100 ° C. of 10 to 300 MPa is attached to the inner surface of the green tire so as to be in contact with the carcass layer. Is preferred. The tire running performance can be further improved by such a rigidity increasing effect by the polymer film layer.
[0016]
The pneumatic tire obtained by the pneumatic tire manufacturing method described above has a uniform residual distortion of the carcass cord, so that the ground contact property of the tire particularly on a wet road surface is improved, and as a result, the tire running performance is excellent. Yes. That is, on a road surface with low frictional resistance such as a wet road surface, the ground contact state greatly affects the running performance.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the configuration of the present invention will be specifically described with reference to the accompanying drawings.
[0018]
FIG. 1 shows an example of a pneumatic tire to be obtained by the present invention, where 1 is a tread region, 2 is a sidewall region, and 3 is a bead region. A carcass layer 5 is mounted between the pair of left and right bead cores 4 and 4, and an end portion of the carcass layer 5 is folded around the bead core 4 from the inside to the outside of the tire. The carcass layer 5 is formed by arranging a plurality of carcass cords in the tire radial direction. A plurality of belt layers 6 are embedded on the outer peripheral side of the carcass layer 5 in the tread region 1. These belt layers 6 include a plurality of cords inclined with respect to the tire circumferential direction, and the cords are arranged so as to cross each other between the layers.
[0019]
A polymer film layer 7 is laminated inside the carcass layer 5. This polymer film layer 7 functions to improve tire rigidity and also functions as an air permeation preventive layer. However, instead of the polymer film layer 7, an inner liner layer made of a rubber composition similar to the conventional one may be disposed.
[0020]
In the present invention, when manufacturing the pneumatic tire as described above, in order to make the lift rate for the green tire mold in the vulcanization process relatively small at the tread center part and relatively large at the shoulder part, The shape of the green tire is changed in advance before vulcanization.
[0021]
2A to 2C show a method for manufacturing a pneumatic tire according to the first embodiment of the present invention. First, as shown in FIG. 2 (a), a cylindrical body portion X in which a carcass layer 5 is mounted between a pair of left and right bead cores 4 and 4 is inflated in a toroidal shape, so that a plurality of belt layers 6 are formed. The green tire T is assembled by pressure bonding to the inner peripheral surface of the annular tread portion Y including
[0022]
Next, as shown in FIG. 2 (b), the tread portion Y of the green tire T is pressed from the inside of the tire with a core 11 having a radius smaller than the radius of the cross section of the tread portion Y over the entire circumference of the tire. The shape of the part Y is convex on the tire outer side. Thereafter, as shown in FIG. 2C, the deformed green tire T is inserted into the mold M and vulcanized.
[0023]
3A to 3D show a method for manufacturing a pneumatic tire according to the second embodiment of the present invention. First, as shown in FIG. 3 (a), using a belt forming drum 12 that can be expanded and contracted in the drum radial direction and has a convex curved portion 12a extending in the circumferential direction on its outer peripheral surface, A plurality of belt layers 6 and a tread rubber 8 are laminated on the outer peripheral side of the belt forming drum 12 while being molded to form an annular tread portion Y. More specifically, the first belt layer 6 is annularly wound around the outer peripheral side of the belt forming drum 12 having the convex curved portion 12a, and the second belt layer 6 is formed on the outer peripheral side. A belt structure in which the belt layer 6 is curved in the width direction is completed by winding in an annular shape and molding. Thereafter, the tread rubber 8 is annularly wound around the outer peripheral side of the belt structure and shaped, thereby completing the tread portion Y with curvature. The tread rubber 8 may be molded by pressing both edges of the tread rubber 8 against the belt structure from the outer peripheral side, or the belt forming drum 12 is in the range of 0.25 to 1.00%. It may be performed by expanding the diameter.
[0024]
Next, as shown in FIG. 3 (b), a cylindrical body portion X in which a carcass layer 5 is mounted between a pair of left and right bead cores 4 and 4 is inflated into a toroidal shape, so that a plurality of belt layers 6 are formed. The green tire T is assembled by pressure bonding to the inner peripheral surface of the annular tread portion Y including
[0025]
Next, as shown in FIG. 3C, the tread portion Y of the green tire T is pressed from the inside of the tire with a core 11 having a radius smaller than the radius of the cross section of the tread portion Y over the entire circumference of the tire. The shape of the part Y is convex on the tire outer side. In this case, since the tread portion Y is previously molded, the green tire T can be easily deformed. Thereafter, as shown in FIG. 3D, the deformed green tire T is inserted into the mold M and vulcanized.
[0028]
According to the method for manufacturing a pneumatic tire described above, since the shape of the green tire T is changed so that the shape of the tread portion Y protrudes outward from the tire before vulcanization, the green tire T is placed in the mold M. When set and pressed against the inner surface of the mold with a high internal pressure, it is possible to avoid the concentration of tension on the local part of the carcass cord and to uniformize the residual strain of the carcass cord after vulcanization. As a result, tire running performance, particularly running performance on wet road surfaces, can be greatly improved.
[0029]
In the present invention, the lift rate of the green tire T with respect to the mold M in the vulcanization process is −1.0 to 3.0% at the tread center portion and 1.0 to 5.0% at the shoulder portion. preferable. In particular, the lift rate Ls at the shoulder portion is preferably larger than the lift rate Lc at the tread center portion. Here, the shoulder portion refers to a point where a perpendicular is made to the belt layer from the belt end of the belt layer on the outer side in the tire radial direction, and the perpendicular intersects the tire surface. When the outer diameters at the tread center portion and the shoulder portion of the green tire T are Tc and Ts, respectively, and the inner diameters at the tread center portion and the shoulder portion of the mold M are Mc and Ms, respectively, Lc = [(Mc−Tc) / Tc] × 100%, Ls = [(Ms−Ts) / Ts] × 100%.
[0030]
Thus, while making the lift rate Lc at the tread center portion relatively small, the lift rate Ls at the shoulder portion is made relatively large, so that the residual strain of the carcass cord after vulcanization can be more effectively improved. It can be made uniform. If the lift rate Lc at the tread center portion is less than -1.0%, the green tire T may be bitten by the mold M. Conversely, if it exceeds 3.0%, the tire uniformity deteriorates. Further, if the lift rate Ls at the shoulder portion is out of the above range, the tire uniformity is deteriorated similarly to the above.
[0031]
The average tread radius Rt of the green tire T is preferably 50 to 100% of the average tread radius Rm of the mold M. However, the average tread radius Rt of the green tire T is the average radius of the outer surface of the tread in the central 80% region in the width direction of the second belt layer from the carcass side, and the average tread radius Rm of the mold M is This is the average radius of the tread molding surface in the region corresponding to the radius Rt. Thus, by making the tread radius Rt closer to the tread radius Rm, the residual strain of the carcass cord after vulcanization can be more effectively uniformized.
[0032]
The green tire T is usually formed at normal temperature, but the green tire shape is preferably changed in an atmosphere of 50 to 100 ° C. after completion of the forming. At such an ambient temperature, it becomes possible to soften the green tire T without causing the vulcanization to proceed substantially and to easily deform the tire. Then, after the deformation, the green tire T may be cooled while the core or the like is mounted to stabilize the shape.
[0033]
Further, a polymer film layer 7 having a thickness of 0.05 to 0.5 mm and a Young's modulus at 100 ° C. of 10 to 300 MPa is attached to the inner surface of the green tire T so as to be in contact with the carcass layer 5. It is preferable to attach. The tire running performance can be further improved by such a rigidity increasing effect by the polymer film layer 7. If the Young's modulus at 100 ° C. of the polymer film layer 7 is less than 10 MPa, the effect of increasing the rigidity is insufficient, and conversely if it exceeds 300 MPa, the riding comfort deteriorates.
[0034]
The polymer film layer 7 is not particularly limited as long as it exhibits the above physical properties, but can be composed of a thermoplastic resin or a thermoplastic elastomer composition obtained by blending a thermoplastic resin and an elastomer.
[0035]
Examples of the thermoplastic resin include polyamimide 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 Copolymer, PET / PEI copolymer Aromatic polyesters such as polyarylate (PAR), polybutylene naphthalate (PBN), liquid crystal polyester, polyoxyalkylene diimide diacid / polybutylene terephthalate copolymer], polynitrile resins [for example, polyacrylonitrile (PAN), polymethacrylate Ronitrile, acrylonitrile / styrene copolymer (AS), methacrylonitrile / styrene copolymer, methacrylonitrile / styrene / butadiene copolymer], poly (meth) acrylate resin [eg polymethyl methacrylate (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), Livinyl alcohol (PVA), vinyl alcohol / ethylene copolymer (EVOH), polyvinylidene chloride (PVDC), polyvinyl chloride (PVC), vinyl chloride / vinylidene chloride copolymer, vinylidene chloride / methyl acrylate copolymer) , Cellulose resins [eg cellulose acetate, cellulose acetate butyrate], fluororesins [eg polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), polychlorofluoroethylene (PCTFE), tetrafluoroethylene / ethylene copolymer ( ETFE)], imide resins [for example, aromatic polyimide (PI)] and the like.
[0036]
The thermoplastic elastomer composition in which the thermoplastic resin and the elastomer are blended can be constituted by mixing the elastomer with the thermoplastic resin described above, and if it has an air permeation preventing action, the kind of material and the mixing ratio Etc. are not particularly limited.
[0037]
Examples of the elastomer blended with the thermoplastic resin 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, bromide of Br-IIR, Cl-IIR, isobutylene paramethylstyrene copolymer (Br-IPMS), chloroprene rubber (CR), hydrin rubber (CHC, CHR) , Chlorosulfonated polyethylene (CSM), chlorine Polyethylene (CM), maleic acid-modified chlorinated polyethylene (M-CM)], silicon rubber (for example, methyl vinyl silicon rubber, dimethyl silicon rubber, methyl phenyl vinyl silicon rubber), sulfur-containing rubber (for example, polysulfide rubber), fluoro rubber (for example, 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).
[0038]
A method for producing a thermoplastic elastomer composition is a method in which a thermoplastic resin component and an elastomer component (unvulcanized product in the case of rubber) are previously melt-kneaded with a twin-screw kneading extruder or the like to form a continuous phase (matrix). By dispersing the elastomer component as a dispersed phase (domain) in the plastic resin. When the elastomer component is vulcanized, a vulcanizing agent may be added under kneading to dynamically vulcanize the elastomer component. 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 component is not particularly limited, and a screw extruder, a kneader, a Banbury mixer, a biaxial kneading extruder, or the like can be used. Among these, it is preferable to use a twin-screw kneading extruder for kneading the thermoplastic resin and the elastomer component and for dynamic vulcanization of the elastomer component. Further, two or more types of kneaders may be used and sequentially kneaded. As conditions for melt kneading, the temperature may be equal to or higher than the temperature at which the thermoplastic resin melts. The shear rate during kneading is 1000 to 7500 sec. ^-1 Is preferred. 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.
[0039]
When the compatibility between the specific thermoplastic resin and the elastomer component is different from each other, it is preferable to make them compatible by using an appropriate compatibilizing agent as the third component. By mixing a compatibilizing agent with the system, the interfacial tension between the thermoplastic resin and the elastomer component is reduced, and as a result, the diameter of the rubber particles forming the dispersed phase becomes finer. It will be expressed effectively. Such a compatibilizing agent is generally a copolymer having both or one structure of a thermoplastic resin and an elastomer component, or an epoxy group, carbonyl group, halogen group, amino group capable of reacting with the thermoplastic resin or elastomer component. A copolymer having a group, an oxazoline group, a hydroxyl group and the like can be taken. These may be selected according to the kind of the thermoplastic resin and the elastomer component to be mixed, but those usually used include styrene / ethylene-butylene block copolymer (SEBS) and its maleic acid modified product, EPDM, EPDM / EPDM / Examples thereof include styrene or EPDM / acrylonitrile graft copolymer and a maleic acid modified product thereof, styrene / maleic acid copolymer, and reactive phenoxin. The amount of the compatibilizing agent is not particularly limited, but is preferably 0.5 to 10 parts by weight with respect to 100 parts by weight of the polymer component (total of the thermoplastic resin and the elastomer component).
[0040]
The composition ratio between the specific thermoplastic resin component (A) and the elastomer component (B) in the case of blending the thermoplastic resin and the elastomer is not particularly limited and may be appropriately determined depending on the Young's modulus and the thickness of the molded body. However, the preferred range is 90/10 to 30/70 by weight.
[0041]
In addition to the above essential polymer component, the polymer composition according to the present invention may be mixed with other polymers such as the above-described compatibilizer polymer within a range that does not impair the necessary characteristics of the tire polymer composition of the present invention. it can. The purpose of mixing other polymers is to improve the compatibility between the thermoplastic resin and the elastomer component, to improve the molding processability of the molded material, to improve heat resistance, and to reduce costs. Examples of the material used for this include polyethylene (PE), polypropylene (PP), polystyrene (PS), ABS, SBS, polycarbonate (PC), and the like. In the polymer composition according to the present invention, fillers (calcium carbonate, titanium oxide, alumina, etc.), carbon black, white carbon and other reinforcing agents generally blended in polymer blends, softeners, plasticizers, Processing aids, pigments, dyes, anti-aging agents, and the like can be optionally blended so long as the air permeability and Young's modulus requirements are not impaired.
[0042]
The elastomer component can also be dynamically vulcanized when mixed with a thermoplastic resin. The vulcanizing agent, vulcanization aid, vulcanization conditions (temperature, time), etc. in the case of dynamically vulcanizing the elastomer component may be appropriately determined according to the composition of the elastomer component to be added, and are particularly limited. It is not a thing.
[0043]
As the vulcanizing agent, a general rubber vulcanizing agent (crosslinking agent) can be used. Specifically, examples of ionic vulcanizing agents include powdered sulfur, precipitated sulfur, highly dispersible sulfur, surface-treated sulfur, insoluble sulfur, dimorpholine disulfide, alkylphenol disulfide, and the like. About 4 phr [parts by weight per 100 parts by weight of rubber component (polymer)] can be used.
[0044]
Organic peroxide vulcanizing agents include benzoyl peroxide, t-butyl hydroperoxide, 2,4-dichlorobenzoyl peroxide, 2,5-dimethyl-2,5-di (t-butyl). Peroxy) hexane, 2,5-dimethylhexane-2,5-di (peroxylbenzoate) and the like are exemplified, and for example, about 1 to 20 phr can be used.
[0045]
Furthermore, examples of the phenol resin-based vulcanizing agent include bromides of alkylphenol resins, mixed crosslinking systems containing halogen donors such as tin chloride and chloroprene, and alkylphenol resins. For example, about 1 to 20 phr is used. Can do.
[0046]
In addition, zinc white (about 5 phr), magnesium oxide (about 4 phr), risurge (about 10-20 phr), p-quinonedioxime, p-dibenzoylquinonedioxime, tetrachloro-p-benzoquinone, poly-p- Examples thereof include dinitrosobenzene (about 2 to 10 phr) and methylenedianiline (about 0.2 to 10 phr).
[0047]
Moreover, you may add a vulcanization accelerator as needed. Examples of the vulcanization accelerator include general vulcanization accelerators such as aldehyde / ammonia, guanidine, thiazole, sulfenamide, thiuram, dithioate, thiourea, etc. About 2 phr can be used.
[0048]
Specifically, as the aldehyde / ammonia vulcanization accelerator, hexamethylenetetramine and the like, as the guanidinium vulcanization accelerator, diphenyl guanidine, etc., as the thiazole vulcanization accelerator, dibenzothiazyl disulfide ( DM), 2-mercaptobenzothiazole and its Zn salt, cyclohexylamine salt and the like, as sulfenamide vulcanization accelerators, cyclohexylbenzothiazylsulfenamide (CBS), N-oxydiethylenebenzothiazyl- As a thiuram vulcanization accelerator such as 2-sulfenamide, Nt-butyl-2-benzothiazole sulfenamide, 2- (thymolpolynidithio) benzothiazole, tetramethylthiuram disulfide (TMTD) , Tetraethylthiuram disulfide, tetrame Examples of dithioate-based vulcanization centering agents such as rutiuram monosulfide (TMTM) and dipentamethylene thiuram tetrasulfide include Zn-dimethinidithiocarbamate, Zn-diethyldithiocarbamate, Zn-di-n-butyldithiocarbamate. Zn-ethylphenyldithiocarbamate, Te-diethyldithiocarbamate, Cu-dimethyldithiocarbamate, Fe-dimethyldithiocarbamate, pipecoline pipecolyldithiocarbamate, etc. Examples of thiourea vulcanization accelerators include ethylenethiourea, diethylthiourea, etc. Can be mentioned.
[0049]
Moreover, as a vulcanization | cure acceleration | stimulation adjuvant, the general rubber adjuvant can be used together, for example, zinc white (about 5 phr), stearic acid, oleic acid, and these Zn salts (about 2-4 phr) Etc. can be used.
[0050]
The film thus obtained has a structure in which an elastomer is dispersed as a discontinuous phase in a thermoplastic resin matrix. By adopting such a structure, the film can be provided with sufficient flexibility and sufficient low air permeability due to the effect of the resin layer of the continuous phase, and molding of a thermoplastic resin regardless of the amount of elastomer. You can get sex.
[0051]
【Example】
For pneumatic tires having a tire size of 215 / 45ZR17, tires 1 to 3 of the present invention were obtained based on the procedures shown in FIGS. Moreover, based on the normal procedure which does not give a deformation | transformation process to a green tire, the reference tire and the contrast tires 1-3 which remove | deviate from the prescription | regulation of this invention were obtained. The tire specifications are shown in Table 1. In Table 1, the average tread radius of the green tire is indicated by an index with the average tread radius of the mold being 100, but a negative value means that the tread portion is recessed inside the tire.
[0052]
[Table 1]

[0053]
These tires were tested by a test driver to evaluate the driving feeling on the dry road surface, the driving feeling on the wet road surface, the driving time on the wet road surface, and the driving time on the dry road surface. It was shown to. The running feeling is based on 3.0, and the larger the value, the better the feeling. The running time is indicated by an index with the reference tire being 100, and the smaller the value, the shorter the running time.
[0054]
[Table 2]

[0055]
As can be seen from Table 2, all of the tires 1 to 3 of the present invention have better running feeling than the reference tire, and also have better running performance on wet road surfaces. Especially this invention tire 1-2 provided with the polymer film layer improved not only the running performance on the wet road surface but also the running performance on the dry road surface.
[0056]
Next, tires 4 to 6 of the present invention were obtained for pneumatic tires of tire size 215 / 45ZR17 based on the procedure of FIGS. Further, a reference tire was obtained based on a normal procedure in which the green tire was not deformed. Table 3 shows the tire specifications. In Table 3, the average tread radius of the green tire and the curved radius of the belt drum are indicated by an index with the average tread radius of the mold being 100.
[0057]
[Table 3]

[0058]
These tires were subjected to a running test by a test driver, and the running feeling on a wet road surface and high-speed durability were evaluated. The results are shown in Table 4. The running feeling is based on 3.0, and the larger the value, the better the feeling. The high-speed durability is indicated by an index with the reference tire as 100, and the larger the value, the better the durability.
[0059]
[Table 4]

[0060]
As can be seen from Table 4, all of the tires 4 to 6 of the present invention had better running feeling than the reference tire, and excellent high-speed durability.
[0065]
【The invention's effect】
As described above, according to the present invention, the cylindrical body portion formed by mounting the carcass layer between the pair of left and right bead cores is inflated in a toroidal shape, and the annular tread portion including a plurality of belt layers is formed. After assembling the green tire by crimping to the inner peripheral surface, the tread part of the green tire is spread over the entire circumference of the tire A core having a radius smaller than the radius of the cross section of the tread portion. Pressing from the inside of the tire to make the shape of the tread convex toward the outside of the tire and inserting the deformed green tire into the mold for vulcanization, the residual distortion of the carcass cord after vulcanization It can be made uniform and tire running performance can be improved.
[Brief description of the drawings]
FIG. 1 is a tire meridian half sectional view showing an example of a pneumatic tire to be obtained in the present invention.
2A and 2B show a method for manufacturing a pneumatic tire according to the first embodiment of the present invention, in which FIG. 2A is a cross-sectional view showing a green tire assembly process, and FIG. 2B is a cross-sectional view showing a green tire deformation process; (C) is a half sectional view showing a vulcanization step.
FIGS. 3A and 3B show a method for manufacturing a pneumatic tire according to a second embodiment of the present invention, wherein FIG. 3A is a cross-sectional view showing a tread portion forming process, and FIG. 3B is a cross-sectional view showing a green tire assembly process; (C) is sectional drawing which shows the deformation | transformation process of a green tire, (d) is a half sectional view which shows a vulcanization | cure process.
[Explanation of symbols]
1 Tread area
2 Side wall area
3 Bead area
4 Bead core
5 Carcass layer
6 Belt layer
7 Polymer film layer
8 Tread rubber
11 core
12 Belt forming drum
12a Curved part
X Body part
Y tread
T green tire
M mold

Claims (8)

A green tire is obtained by inflating a cylindrical body part formed by mounting a carcass layer between a pair of left and right bead cores in a toroidal shape and crimping it on the inner peripheral surface of an annular tread part including a plurality of belt layers. After assembling, the tread portion of the green tire is pressed from the inside of the tire with a core having a radius smaller than the radius of the cross section of the tread portion over the entire circumference of the tire to make the shape of the tread portion convex toward the outside of the tire, A method for manufacturing a pneumatic tire in which a deformed green tire is inserted into a mold and vulcanized.   Using a belt forming drum having a convex curved portion on the outer peripheral surface, a plurality of belt layers and a tread rubber are laminated on the outer peripheral side of the belt forming drum to form an annular tread portion. After assembling a green tire by inflating a cylindrical body portion formed by mounting a carcass layer between a pair of bead cores into a toroidal shape and press-bonding to the inner peripheral surface of the tread portion, The tread portion is pressed from the inside of the tire with a core having a radius smaller than the radius of the cross section of the tread portion over the entire circumference of the tire so that the shape of the tread portion is convex toward the outside of the tire. A method of manufacturing a pneumatic tire. Lift rate for the mold of the green tire in the vulcanizing process is a -1.0～3.0% in the tread center portion, of claim 1-2 which is 1.0 to 5.0% by shoulder portion The manufacturing method of the pneumatic tire in any one. The manufacturing method of the pneumatic tire in any one of Claims 1-3 which made the lift rate in the said shoulder part larger than the lift rate in the said tread center part. The method for producing a pneumatic tire according to any one of claims 1 to 4 , wherein an average tread radius of the green tire is 50 to 100% of an average tread radius of the mold. Performs tread deformation operation after the green tire assembly in an atmosphere of 50 to 100 ° C., according to any one of claims 1 to 5 so as to stabilize the shape of the green tire is cooled remain in that state Method of manufacturing a pneumatic tire. A polymer film layer having a thickness of 0.05 to 0.5 mm and a Young's modulus at 100 ° C of 10 to 300 MPa is attached to the inner surface of the green tire so as to be in contact with the carcass layer. The manufacturing method of the pneumatic tire in any one of 1-6 . A pneumatic tire obtained by the production method of the pneumatic tire according to any one of claims 1-7.

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