JP4305604B2 - Pneumatic tire manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a pneumatic tire, and more particularly, a resin-blended inner liner in which an unvulcanized tire body having a carcass layer on the tire inner surface and a thermoplastic resin are blended and laminated on the inner surface of the carcass layer. In a pneumatic tire manufacturing method in which a rubber composite material formed by laminating layers is molded and the rubber composite material is pressurized and heated to manufacture a pneumatic tire, so as to prevent occurrence of defects due to air accumulation between the stacked layers The present invention relates to a method for producing a rubber product.
[0002]
[Prior art]
In recent years, pneumatic tires are strongly demanded to be lighter in order to improve the fuel efficiency of vehicles. Therefore, for example, a technology has been proposed in which a film-like resin compounding member (resin compounding inner liner layer) in which a thermoplastic resin is compounded is used for an inner liner layer made of rubber, which has been used as an air permeation prevention layer. Has been. By blending a resin with low air permeability compared to rubber and using an inner liner layer member that is thinner than an inner liner layer made of conventional rubber, the weight of the pneumatic tire is reduced. .
[0003]
However, using an inner liner layer which is a resin blend, a green tire the air is formed in a state sandwiched between a large amount between the resin formulation inner liner layer and the tire components during the tire molding (unvulcanized tire body) When vulcanized and the amount of air exceeds the amount absorbed or permeated by the surrounding members during vulcanization, the air remains as a relatively high-pressure gas around the members, and the inside of the tire in the final vulcanization stage The internal pressure of the molding bladder that is pressurized from the pressure is reduced and contracted, and when the tire surface is released to atmospheric pressure, the strength at high temperature is lower than that of rubber, so the resin-blended inner liner member expands the gas between the members There was a problem that it could not withstand the force and protruded greatly to the outside. Therefore, conventionally, as a countermeasure, when laminating the resin-blended inner liner member and the unvulcanized tire body , the pressure is sequentially pressed from the end with a roller so that the air is not confined as much as possible from the beginning. There is a method of substantially reducing the amount of air between layers to a limit amount or less that can be absorbed or permeated by surrounding members.
[0004]
However, this method alone cannot exhaust the air sufficiently, or the air collected by crimping with a roller accumulates locally due to steps, minute dents, tightness of adhesion, etc. By tightly adhering, air is enclosed, and during vulcanization, the air cannot move and disperse to the periphery, so the amount that can be absorbed and permeated by surrounding members is locally exceeded, and the resin-containing inner liner layer is After vulcanization, there was a problem that the bulge protruded to the outside locally.
[0005]
In addition, as a method of effectively discharging the air trapped between both members to the outside, a twisted yarn is arranged between both members, and during vulcanization, the air is dispersed to the periphery and discharged to the outside through a gap in the twisted yarn. Techniques to do so are commonly used. However, the twisted yarn cannot be used because the adhesive strength with the resin-blended inner liner member is significantly inferior to that of the rubber member (unvulcanized tire body) .
[0006]
[Problems to be solved by the invention]
An object of the present invention is to provide a pneumatic tire capable of effectively dispersing air trapped between a resin-blended inner liner layer member and an unvulcanized tire body and preventing occurrence of defects due to air accumulation. It is in providing the manufacturing method of.
[0007]
[Means for Solving the Problems]
A method for producing a pneumatic tire according to the present invention that achieves the above object includes a resin-blended inner liner that is blended with an unvulcanized tire body having a carcass layer on the tire inner surface and a thermoplastic resin and is laminated on the inner surface of the carcass layer. In the method of manufacturing a pneumatic tire, in which a rubber composite material formed by laminating layers is molded, and the rubber composite material is pressurized and heated to manufacture a pneumatic tire, the resin-containing inner liner layer and the unvulcanized tire A strong adhesive portion and a weak adhesive portion having different adhesive forces between the main body and a weakly adhesive portion are mixedly arranged, and the weak adhesive portion is confined between the unvulcanized tire main body and the resin-blended inner liner layer. It is characterized by an air escape portion in which air moves between the layers and is dispersed to the surroundings.
[0008]
In this way, the rubber composite material is molded into a structure having an air escape portion that disperses air around it, so that when the rubber composite material is pressurized and heated, the air escape portion causes the resin-containing inner liner member and the unvulcanized tire body The air trapped in between can be effectively dispersed to the surroundings, so that it is possible to avoid the occurrence of an air pool in which air is concentrated. Therefore, it is possible to prevent defects caused by air accumulation.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings.
[0010]
1 shows a pneumatic tire manufactured by the manufacturing method of the pneumatic tire of the present invention, 1 denotes a tread portion, 2 a sidewall portion, numeral 3 denotes a bead portion. A carcass layer 4 is mounted between the left and right bead portions 3, and both end portions 4 a are folded back from the inside to the outside of the tire so as to sandwich the bead filler 6 around the bead core 5 embedded in the bead portion 3. . A belt layer 7 is disposed on the outer peripheral side of the carcass layer 4 of the tread portion 1.
[0011]
In the tire body M having the carcass layer 4 on the inner surface of the tire as described above, the film-shaped resin blending member 8 in which a thermoplastic resin is blended is laminated on the inner surface 4b of the carcass layer 4 as an inner liner layer. Further, a thin buffer rubber layer called a tie rubber layer may be provided between the film-shaped resin compounding member 8 and the carcass layer 4.
[0012]
The pneumatic tire having the above-described configuration is manufactured according to a conventionally known manufacturing process. For example, a film-shaped resin compounded member before heating is wound as an inner liner layer on a first molding drum, and an unvulcanized carcass layer is laminated and bonded on the resin compounded member.
[0013]
After placing bead cores with unvulcanized bead fillers on the outer periphery at both ends of the carcass layer, both ends of the carcass layer are folded around the bead core. An unvulcanized side rubber layer constituting the sidewall portion 2 and the bead portion 3 is wound around both sides of the carcass layer, and then shaped into a toroidal shape to form a first tire body.
[0014]
On the other hand, an unvulcanized belt layer is wound on the second molding drum, and an unvulcanized tread rubber layer constituting the tread portion 1 is disposed on the belt layer to mold the second tire body.
[0015]
A second tire body is disposed on the outer peripheral side of the first tire body, and a green tire (rubber composite material) formed by laminating an unvulcanized tire body (unvulcanized rubber member) and a resin compounding member is formed. . Thereafter, the green tire is put into a vulcanizer and heated under pressure and vulcanized to obtain the pneumatic tire.
[0016]
In the manufacturing method of the pneumatic tire which consists of such a manufacturing process, this invention is characterized by the following points. That is, when the green tire (rubber composite material) G, which is in a state before vulcanization of the pneumatic tire, is formed, the green tire G is heated in a film-shaped resin-blended innerliner member (resin-blended innerliner layer). ) 8 'and the uncured carcass layer (a part of the unvulcanized tire body ) are molded into a structure having an air escape portion for escaping air to the surroundings.
[0021]
FIG. 2 is an explanatory view showing an example in which a strong adhesive portion and a weak adhesive portion are mixedly arranged on a resin-blended inner liner member, and adhesives having different adhesive forces on the outer side surface 8′a of the resin-blended inner liner member 8 ′. (A) is a plan view thereof, and (b) is an enlarged cross-sectional view of a main part when laminated with an unvulcanized carcass layer . A strong adhesive portion 10'A that adheres well to the carcass layer 4 'and a weak adhesive portion 10'B that hardly adheres to the carcass layer 4' are mixedly arranged, and between the resin compounding member 8 'and the carcass layer 4', The weak adhesive portion 10'B is an air escape portion. The strong adhesion portion 10′A is arranged in an island shape, and the weak adhesion portion 10′B spreading in a sea shape continuously extends to the edges of both end portions in the tire width direction of the resin compounding member 8 ′. Moreover, even if it does not provide to both edge parts, you may provide partially as needed. Further, a weak adhesion portion may be laminated in an island shape on the adhesive layer so as to have a similar sea-island configuration. By adopting such a configuration, when there is an air reservoir, the weak adhesive part is selectively spread by the pressure of the vulcanization bladder, and can be dispersed around.
[0023]
Thus, in the method of forming a green tire formed by laminating the unvulcanized tire body and the resin-blended inner liner member 8 ′ and pressurizing and heating the green tire, The air escape portion that disperses the trapped air around the unvulcanized tire body and the resin-blended inner liner member 8 ′ has a configuration in which air is evacuated during vulcanization by pressure heating. Since it is possible to disperse to the surroundings through the escape portion or discharge to the outside so that the air can be less than the limit amount that can be absorbed or permeated to the surrounding members, the occurrence of defects due to air accumulation is reduced. Can be prevented.
[0024]
In the present invention, as described above, the air escape portion preferably extends to both edges of each member to discharge air to the outside, but may extend to one edge. . In addition, it is not always necessary to extend to the edge, and the air escape portion is arranged so as to be dispersed so that the air can be absorbed or permeated to the surrounding members so as to be less than the limit amount, so that the trapped air is concentrated. You may make it avoid generation | occurrence | production.
[0026]
The total area of the strong adhesive portion 10A can be 25% or more and 99% or less of the total area of the contact surface with which they are in contact with each other in the range subjected to processing as in the present invention. If the total contact area of the strong adhesive portion 10A is lower than 25%, the total area of the strong adhesive portion is reduced, and therefore, the strong adhesive portion 10A is easily peeled off during molding. On the other hand, if it exceeds 99%, the air flow path is blocked and the effect of dispersion becomes low. Preferably, it is 50% or more and 97% or less. More preferably, it is 80% or more and 95% or less .
[0031]
The above-described resin-blended inner liner member 8 ′ can be composed of a thermoplastic resin or a thermoplastic resin elastomer composition obtained by blending a thermoplastic resin and an elastomer. The thermoplastic resin may include, for example following a thermoplastic resin such as.
[0032]
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 / N66), nylon 6/66/610 copolymer (N6 / 66/610, nylon MXD6 (MXD6), nylon 6T, nylon 6 / 6T copolymer, nylon 66 / PP copolymer , Nylon 66 / PPS copolymer), and N-alkoxyalkylated products thereof such as 6-nylon methoxymethylated product, 6-610-nylon methoxymethylated product, 612-nylon methoxymethylated product, polyester resin ( For example, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyethylene isophthalate (PEI), PET / PEI copolymer, polyarylate (PAR), polybutylene naphthalate (PBN), liquid crystal polyester, polyoxyalkylene diimidic acid / polybutylate terephthalate copolymer Aromatic polyester), polynitrile resin (for example, polyacrylonitrile (PAN), polymethacrylonitrile, acrylonitrile / styrene copolymer (AS), methacrylonitrile / styrene copolymer, methacrylonitrile / styrene / butadiene copolymer) Polymer), polymethacrylate resin (eg, polymethyl methacrylate (PMMA), polyethyl methacrylate), polyvinyl resin (eg, vinyl acetate, polyvinyl alcohol (PVA), vinyl alcohol / ethylene copolymer) (EVOH), polyvinylidene chloride (PDVC), polyvinyl chloride (PVC), vinyl chloride / vinylidene chloride copolymer, vinylidene chloride / methyl acrylate copolymer, vinylidene chloride / acrylonitrile copolymer), cellulose resin (for example, Cellulose acetate, cellulose acetate butyrate), fluororesin (eg, polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), polychlorofluoroethylene (PCTFE), tetrafluoroethylene / ethylene copolymer), imide resin (eg, Aromatic polyimide (PI)) and the like.
[0033]
Further, the thermoplastic elastomer composition containing a blend of the thermoplastic resin and the elastomer can be constituted by mixing the elastomer with the thermoplastic resin described above, and if it has an air permeation preventing function, the material It is not limited to the kind or mixing ratio. Examples of the elastomer blended with the thermoplastic resin include the following.
[0034]
Diene rubber 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 (for example, ethylene propylene) Rubber (EPDM, EPM), maleic acid-modified ethylene propylene rubber (M-EPM), IIR, isobutylene and aromatic vinyl or diene monomer copolymer, acrylic rubber (ACM), ionomer), halogen-containing gonet (eg Br-IIR) CI-IIR, brominated product of isobutylene paramethylstyrene copolymer (Br-IPMS), chloroprene rubber (CR), hydrin rubber (CHR), chlorosulfonated polyethylene (CSMM)), silicone rubber (for example, methyl vinyl silicone rubber, Dimethyl silicone rubber, methylphenylbi Silicone rubber), sulfur-containing rubber (for example, polysulfide rubber), fluorine rubber (for example, vinylidene fluoride rubber, fluorine-containing vinyl ether rubber, tetrafluoroethylene-propylene rubber, fluorine-containing silicon rubber, fluorine-containing phosphazene rubber), Examples thereof include thermoplastic elastomers (for example, styrene elastomers, olefin elastomers, ester elastomers, urethane elastomers, polyamide elastomers).
[0035]
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 vulcanizing the elastomer component, 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 them, 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 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 1000 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.
[0036]
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 compatibilizer into the system, the interfacial tension between the thermoplastic resin and the elastomer component is reduced, and as a result, the rubber particle size forming the dispersion layer becomes finer, so the characteristics of both components are more 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 (the total of the thermoplastic resin and the elastomer component).
[0037]
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.
[0038]
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.
[0039]
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.
[0040]
A general rubber vulcanizing agent (crosslinking agent) can be used as the vulcanizing agent. Specific examples of the ionic vulcanizing agent 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.
[0041]
Examples of 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), etc. are exemplified, and for example, about 1 to 20 phr can be used.
[0042]
Furthermore, examples of the phenol resin-based vulcanizing agent include bromides of alkyl phenol resins, mixed crosslinking systems containing halogen donors such as tin chloride and chloroprene, and alkyl phenol resins. For example, about 1 to 20 phr is used. Can do.
[0043]
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).
[0044]
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.
[0045]
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, etc., sulfenamide vulcanization accelerators include cyclohexylbenzothiazylsulfenamide (CBS), N-oxydiethylenebenzothiazyl- Tetramethylthiuram disulfide (TMTD) is used as a thiuram vulcanization accelerator such as 2-sulfenamide, Nt-butyl-2-benzothiazole sulfenamide, 2- (thymolpolynidithio) benzothiazole and the like. , 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.
[0046]
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.
[0047]
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.
[0048]
Is an adhesive layer, usually of rubber, phenolic resin, acrylic copolymer, a polymer and a crosslinking agent of isocyanate type or the like coated with adhesive dissolved in a solvent in the film, the heat and pressure at the time of vulcanization formation Adhesive resin such as styrene butadiene styrene copolymer (SBS), ethylene ethyl acrylate (EEA, styrene ethylene block copolymer (SEBS)) is coextruded or laminated with a thermoplastic film. There is a method in which a multilayer film is prepared and adhered to rubber at the time of vulcanization.Solvent adhesives include, for example, phenol resin (Chemlock 220, Rhode), chlorinated rubber (Chemlock 205, Chemlock 234B), isocyanate A system (Chemlock 402) etc. can be illustrated.
[0051]
【The invention's effect】
The present invention as described above, the rubber composite material formed by laminating a green tire body and a thermoplastic resin resin formulation innerliner member formulated with, the unvulcanized tire body and resin formulations inner liner material member Since it has a structure with an air escape portion that disperses the trapped air in the vicinity, air can be effectively dispersed through the air escape portion during pressurization and heating, so defects caused by air accumulation Can be prevented.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a main part of a tire meridian showing an example of a pneumatic tire manufactured by a manufacturing method of the present invention.
FIG. 2 is an explanatory view showing an example in which a strong adhesive portion and a weak adhesive portion are mixedly arranged on the resin-blended inner liner member used in the method for manufacturing a pneumatic tire of the present invention , (a) is a plan view thereof, (B) is a principal part expanded sectional view when laminating | stacking with an unvulcanized carcass layer .
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Tread part 2 Side wall part 3 Bead part 4 Carcass layer 4 'Unvulcanized carcass layer (a part of unvulcanized tire main body)
8 Resin-blended inner liner member 8 'Resin-blended member before heat curing 8'a Outer side surface 10'A Strong adhesive part 10'B Weak adhesive part G Green tire M Tire body

Claims (3)

  A rubber composite material is formed by laminating an unvulcanized tire body having a carcass layer on the inner surface of a tire and a resin-blended inner liner layer blended with a thermoplastic resin and laminated on the inner surface of the carcass layer, and the rubber In a pneumatic tire manufacturing method for manufacturing a pneumatic tire by pressurizing and heating a composite material, a strong adhesive portion and a weak portion having different adhesive forces between the resin-containing inner liner layer and the unvulcanized tire main body. Adhesive part is mixedly arranged, and the weakly adhesive part is an air escape part in which air trapped between the unvulcanized tire body and the resin-blended inner liner layer moves between the layers and is dispersed to the surroundings. A method for manufacturing a tire. The method of manufacturing a pneumatic tire according to claim 1, wherein said resin blend inner liner layer is a film. The method for producing a pneumatic tire according to claim 1 or 2, wherein the resin-containing inner liner layer is made of a thermoplastic resin or a thermoplastic resin elastomer composition obtained by blending a thermoplastic resin and an elastomer.

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