JP5167945B2 - Pneumatic tire manufacturing method - Google Patents

Description

  The present invention relates to a method for producing a pneumatic tire having an inner liner layer made of a thermoplastic elastomer composition in which a thermoplastic resin or a thermoplastic resin component and an elastomer component are blended. More specifically, the present invention improves the peeling of the inner liner layer. The present invention relates to a method for manufacturing a pneumatic tire.

  Conventionally, a pneumatic tire using a thermoplastic resin or a thermoplastic elastomer composition obtained by blending a thermoplastic resin component and an elastomer component for an inner liner layer is well known (for example, see Patent Documents 1 and 2). Thereby, there is an advantage that the inner liner layer can be reduced in weight and fuel efficiency can be improved.

However, if the inner liner layer is composed of a thermoplastic resin or thermoplastic elastomer composition having a high elastic modulus, the force to shrink against deformation is greater than that of rubber, and the viscoelasticity is lower than that of rubber. Tack force is greatly inferior. Therefore, when forming a green tire by expanding the carcass band and crimping the carcass band to the tread band, the inner liner layer easily peels from the adjacent member such as the adjacent tie rubber layer due to the shrinkage phenomenon of the expanded inner liner layer. There was a problem.
JP 2006-198848 A JP 2007-296916 A

  An object of the present invention is to provide a method for producing a pneumatic tire capable of improving the peeling of the inner liner layer in a pneumatic tire having an inner liner layer made of a thermoplastic resin or a thermoplastic elastomer composition. is there.

The method for producing a pneumatic tire according to the present invention that achieves the above object includes expanding a carcass band having an inner liner layer composed of a thermoplastic resin or a thermoplastic elastomer composition obtained by blending a thermoplastic resin component and an elastomer component. In the manufacturing method of a pneumatic tire in which a green tire is formed by pressure bonding to the inner peripheral side of the tread ring, the outer diameter of the carcass band is in a range of 1.1 to 1.4 times the inner diameter of the tread ring. The inner liner layer is plastically deformed by maintaining the state for a predetermined time, and then the expanded carcass band is once reduced in diameter until its outer diameter becomes smaller than the inner diameter of the tread ring. and, the inner circumferential side of the tread ring by upset further the once reduced diameter carcass band in a tread ring And wherein the crimping.

  According to the present invention described above, since the inner liner layer is plastically deformed by holding the carcass band expanded in advance, the shrinkage force of the inner liner layer that works when the carcass band is expanded and pressed onto the tread ring. Can be weakened than before. Therefore, it can suppress that an inner liner layer peels from an adjacent tire structural member, and the peeling of an inner liner layer can be improved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 shows an example of a pneumatic tire manufactured by the method for manufacturing a pneumatic tire of the present invention, where 1 is a tread portion, 2 is a sidewall portion, and 3 is a bead portion.

  A carcass layer 4 embedded in a rubber layer with reinforcing cords extending in the tire radial direction between the left and right bead portions 3 arranged at predetermined intervals in the tire circumferential direction is extended, and both end portions thereof are embedded in the bead portion 3 The bead filler 6 is folded back from the inner side in the tire axial direction so as to sandwich the bead filler 6 around the bead core 5.

  A plurality of belt layers 7 are provided on the outer peripheral side of the carcass layer 4 of the tread portion 1, and a tread rubber layer 8 is disposed on the outer peripheral side of the belt layer 7. A film-like inner liner layer 10 made of a thermoplastic elastomer or a thermoplastic elastomer composition obtained by blending a thermoplastic resin component and an elastomer component is disposed inside the carcass layer 4 with a tie rubber layer 9 interposed therebetween. A side rubber layer 11 is disposed outside the carcass layer 4 of the sidewall portion 2, and a rim cushion rubber layer 12 is provided outside the folded portion of the carcass layer 4 of the bead portion 3.

  Hereinafter, a method of manufacturing the pneumatic tire of FIG. 1 by the manufacturing method of the present invention will be described with reference to FIGS.

  First, as shown in FIG. 2, the carcass band 13 is formed on the forming drum 21 in the same manner as in the prior art. That is, after the cylindrical inner liner layer 10 made of a thermoplastic resin or a thermoplastic elastomer composition is attached to the molding drum 21, an adhesive is applied to the outer surface thereof, and then the unvulcanized tie rubber layer 9 and the unvulcanized tie rubber layer 9 are coated. Sulfur carcass layer 4, bead core 5 to which unvulcanized bead filler 6 is attached, unvulcanized rim cushion rubber layer 12 and unvulcanized side rubber layer 11 are sequentially attached to form cylindrical carcass band 13 as a molding drum. 1 is molded.

  The inner liner layer 10 may be wound in a cylindrical shape instead of a cylindrical shape. Alternatively, an adhesive layer may be formed on the inner liner layer 10 in advance and attached to the forming drum 21.

  The formed carcass band 13 is removed from the forming drum 21 and attached to the shaping drum 22 as shown in FIG. The carcass band 13 is held for a predetermined time in the expanded state, and thereby the inner liner layer 10 is plastically deformed. The amount of expansion of the carcass band 13 that deforms beyond the yield point may be an amount that can impart plastic deformation to the inner liner layer 10.

Preferably, Ru is upset the carcass band 13 in the range of 1.4 times or less of the inner diameter Y of the tread ring 14 whose outer diameter is described later (see FIG. 5). If the diameter is increased beyond 1.4Y, wrinkles are likely to occur in the inner liner layer 10, which is not preferable. The lower limit for improving the release, you the carcass band 13 to the outside diameter of more than 1.1 times the inner diameter Y of the tread ring 14.

  The holding time is not particularly limited as long as plastic deformation can be imparted to the inner liner layer 10. Preferably, the upper limit value is 120 seconds or less in terms of tire manufacturing efficiency. The lower limit is 0.1 seconds or longer, preferably 1 second or longer, from the viewpoint of plastic deformation of the inner liner layer 10.

  The step of plastically deforming the inner liner layer 10 is preferably performed in a temperature-adjustable room 23 as shown in FIG. The temperature in the room 23 is preferably an atmosphere of 20 to 100 ° C. When the temperature in the room 23 is lower than 20 ° C., the rigidity becomes high and deformation control becomes difficult. On the other hand, if the temperature exceeds 100 ° C., the softening of the resin is so great that it becomes difficult to keep the deformation, and the vulcanization of the unvulcanized rubber may proceed. The temperature may be appropriately selected depending on the amount of expansion of the carcass band 1 and the holding time. Desirably, 40-80 degreeC is good from the point of coexistence of ease of plastic deformation and workability.

When the step of plastically deforming the inner liner layer 10 is completed, the carcass band 13 is once reduced in diameter as shown in FIG. The amount of diameter reduction of the carcass band 13 is made smaller than the inner diameter of the tread ring 14 to be bonded in the next step . Reduced diameter range, range slack in the inner liner layer 10 which is plastically deformed does not occur, i.e., it is a range of not less than carcass band diameter before plastic deformation.

  Next, the previously formed tread ring 14 is transferred and placed on the outer peripheral side of the carcass band 13 as shown in FIG. The tread ring 14 is formed on another forming drum, and is an annular body in which the unvulcanized tread rubber layer 8 is bonded to the outer peripheral side of the unvulcanized belt layer 7.

  After the tread ring 14 is disposed, as shown in FIG. 6, an internal pressure is applied in the carcass band 13, the carcass band 13 is expanded in a toroidal shape, and is crimped to the inner peripheral side of the tread ring 14. Is molded. This green tire is pressurized and heated in a mold and vulcanized to obtain the pneumatic tire of FIG.

  According to the present invention described above, since the inner liner layer 10 is plastically deformed in advance by expanding the carcass band 13 and maintaining the state for a predetermined time, the carcass band 13 is expanded and pressure-bonded to the tread ring 14. In doing so, the shrinkage force of the expanded inner liner layer 10 can be relaxed. Therefore, the peeling of the inner liner layer 10 from the adjacent tie rubber layer 9 can be suppressed, and the peeling failure of the inner liner layer 10 can be improved.

  In the present invention, examples of the thermoplastic resin used for the inner liner layer 10 include polyamide resins [eg, 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 ( MXD6), nylon 6T, nylon 6 / 6T copolymer, nylon 66 / PP copolymer, nylon 66 / PPS copolymer] and their N-alkoxyalkylated products, for example, methoxymethylated products of nylon 6, nylon 6 / 610 copolymer methoxymethylated, nylon 612 methoxymethylated, poly Stell resin (for example, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyethylene isophthalate (PEI), 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), (meth) Acrylonitrile / styrene copolymer, (meth) acrylonitrile / styrene / butadiene copolymer], polymethacrylate resin [for example, polymethyl methacrylate (PMMA), polyethyl methacrylate], poly Vinyl resins [eg, vinyl acetate, polyvinyl alcohol (PVA), vinyl alcohol / ethylene copolymer (EVOH), polyvinylidene chloride (PDVC), polyvinyl chloride (PVC), vinyl chloride / vinylidene chloride copolymer, chloride Vinylidene / methyl acrylate copolymer, vinylidene chloride / acrylonitrile copolymer (ETFE)], cellulose resin [eg, cellulose acetate, cellulose acetate butyrate], fluorine resin [eg, polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), polychlorofluoroethylene (PCTFE), tetrafluoroethylene / ethylene copolymer], an imide resin [for example, aromatic polyimide (PI)] and the like can be preferably used.

  The thermoplastic elastomer composition can be constituted by mixing an elastomer component with the above-described thermoplastic resin component. Examples of the elastomer used include diene rubbers and hydrogenated products thereof [for example, natural rubber (NR), isoprene rubber (IR), epoxidized natural rubber, styrene bradiene rubber (SBR), bradiene rubber (BR, high Cis BR and low cis BR), nitrile rubber (NBR), hydrogenated NBR, hydrogenated SBR], olefin rubber [for example, 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, CI-IIR, bromine of isobutylene paramethylstyrene copolymer (Br-IPMS), chloroprene rubber (CR), hydride Rubber (CHR), chlorosulfonated polyethylene rubber (CSM), chlorinated polyethylene rubber (CM), maleic acid-modified chlorinated polyethylene rubber (M-CM)], silicone rubber [eg, methyl vinyl silicone rubber, dimethyl silicone rubber, Methyl phenyl vinyl silicon 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) Rubbers], thermoplastic elastomers [for example, styrene elastomers, olefin elastomers, ester elastomers, urethane elastomers, polyamide elastomers] and the like can be preferably used.

  When the above-mentioned specific thermoplastic resin component and the elastomer component are different in compatibility, they can be made compatible by using a suitable compatibilizer as the third component. By mixing the compatibilizer with the blend system, the interfacial tension between the thermoplastic resin and the elastomer component is reduced, and as a result, the particle size of the rubber forming the dispersion layer becomes fine. It will be expressed more effectively. As such a compatibilizing agent, generally a copolymer having a structure of both or one of the thermoplastic resin and the elastomer component, or an epoxy group, a carbonyl group, a halogen group, which can react with the thermoplastic resin or the elastomer component, The structure of a copolymer having an amino 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, EPM. EPDM / styrene or EPDM / acrylonitrile graft copolymer and its maleic acid modified product, styrene / maleic acid copolymer, reactive phenoxin and the like. 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).

  The composition ratio of 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 the film thickness, air permeation resistance, flexibility The weight range (A) / (B) is preferably 10/90 to 90/10, more preferably 15/85 to 90/10.

  The thermoplastic elastomer composition according to the present invention includes, in addition to the above essential polymer component, the compatibilizer polymer described above and the like within a range that does not impair the necessary characteristics of the thermoplastic elastomer composition for the inner liner layer of the present invention. The polymers can be mixed. 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 material, to improve heat resistance, to reduce costs, etc. Examples of the material used include polyethylene (PE) polypropylene (PP), polystyrene (PS), ABS, SBS, polycarbonate (PC) and the like. The thermoplastic elastomer composition according to the present invention further includes a filler (calcium carbonate, titanium oxide, alumina, etc.), a reinforcing agent such as carbon black and white carbon, a softener, a plasticizer, etc. Agents, processing aids, pigments, dyes, anti-aging agents, and the like can be arbitrarily added as long as the above elastic modulus requirements are not impaired.

  The elastomer component can also be dynamically vulcanized when mixed with a thermoplastic resin. The vulcanizing agent, vulcanization aid, vulcanization conditions (temperature, time), etc. when dynamically vulcanizing may be appropriately determined according to the composition of the elastomer component to be added, and are not particularly limited. .

  A general rubber vulcanizing agent (crosslinking agent) can be used as the vulcanizing agent. Specific examples of the sulfur 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 [phr: parts by weight per 100 parts by weight of rubber component (elastomer)] can be used.

  Organic peroxide vulcanizing agents include benzoyl peroxide, t-butyl hydroperoxide, 2,4-dichlorobenzoyl peroxide, 2,5-dimethyl-2,5-di (t-butyl peroxide). Oxy) hexane, 2,5-dimethylhexane-2,5-di (peroxylbenzoate), etc. are exemplified, and for example, about 1 to 20 phr can be used.

  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. 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).

  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. 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, sulfenamide vulcanization accelerators include cyclohexylbenzothiazylsulfenamide (CBS), N-oxydiethylenebenzothiazyl-2- As thiuram vulcanization accelerators such as sulfenamide, Nt-butyl-2-benzothiazole sulfenamide, 2- (thymolpolynyldithio) benzothiazole, tetramethylthiuram disulfide (TMTD), tetraethyl Thiuram disulfide, tetrame Examples of dithioate-based vulcanization accelerators such as lutiuram monosulfide (TMTM) and dipentamethylene thiuram tetrasulfide include Zn-dimethyldithiocarbamate, Zn-diethyldithiocarbamate, Zn-di-n-butyldithiocarbamate, Zn -Ethyl phenyl dithiocarbamate, Te-diethyl dithiocarbamate, Cu-dimethyldithiocarbamate, Fe-dimethyldithiocarbamate, pipecoline pipecolyldithiocarbamate, etc. Examples of thiourea vulcanization accelerators include ethylenethiourea and diethylthiourea be able to.

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. 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. Moreover, it is preferable that the shear rate at the time of kneading | mixing is 1000-7500Sec < ^-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 may be extruded into a cylindrical shape or a sheet shape by a conventional method using a normal film extruder.

  The film thus obtained has a structure in which the elastomer component (B) is dispersed as a discontinuous phase in the matrix of the thermoplastic resin (A). By adopting such a structure, the film can be provided with sufficient flexibility and sufficient rigidity due to the effect of the resin layer as a continuous phase, and at the time of molding, regardless of the amount of the elastomer component, Equivalent moldability can be obtained.

  Adhesion between adjacent tire components (tie rubber layer in FIG. 1) is performed by applying an ordinary rubber-based, phenolic resin-based, acrylic copolymer-based, isocyanate-based polymer and a crosslinking agent dissolved in a solvent, Adhesive resin such as styrene butadiene styrene copolymer (SBS), ethylene ethyl acrylate (EEA), styrene ethylene butylene block copolymer (SEBS), etc. with film There is a method in which a multilayer laminate is prepared by coextrusion or lamination, and is adhered to an adjacent tire constituent member at the time of vulcanization. Examples of the solvent-based adhesive include phenol resin (Chemlock 220, Rhode), chlorinated rubber (Chemlock 205, Chemlock 234B), isocyanate (Chemlock 402), and the like.

  In the above embodiment, the tire has a configuration in which the tie rubber layer 9 is adjacent to the inner liner layer 10 made of a thermoplastic resin or a thermoplastic elastomer composition. However, the present invention is not limited thereto, and the thermoplastic resin or the thermoplastic elastomer is not limited thereto. As long as the tire has the inner liner layer 10 made of the composition, it can be applied to any tire.

A method ( Examples 1 to 11 and Reference Examples 1 to 5 ) and an inner liner in which a tire size is commonly used in 165SR13 and an inner liner layer made of a thermoplastic elastomer composition having the composition shown in Table 1 is plastically deformed. 30 green tires each having the structure shown in FIG. 1 were formed by a conventional method (conventional example) in which there is no step of plastically deforming the layers. In Examples 1 to 11 and Reference Examples 1 to 5 , the amount of expansion, the temperature during plastic deformation, and the holding time are as shown in Table 2. The diameter when the expanded carcass band is contracted is 0.5 times (0.5 Y) the inner diameter Y of the tread ring.

  The presence or absence of peeling of the inner liner layer of the green tire molded by each method was examined, and the result was evaluated in three stages, ◯, Δ, and X. ○ indicates 0 peeling of the inner liner layer, Δ indicates 1-10 peeling of the inner liner layer, and x indicates 11-30 peeling of the inner liner layer.

  Further, in a vulcanized tire obtained by vulcanizing the above green tire according to a conventional method under vulcanization conditions of 185 ° C. × 15 minutes and a pressure of 2.3 MPa, the presence or absence of wrinkles in the inner liner layer was examined. Evaluation was made in three stages, Δ and ×. ○ is 0 wrinkles in the inner liner layer, Δ is 1-10 wrinkles in the inner liner layer, and x is 11-30 wrinkles in the inner liner layer. These results are shown in Table 2.

Table 2 shows that this invention can suppress peeling of an inner liner layer. It can also be seen that the inner liner layer peeling can be further improved by appropriately adjusting the amount of expansion, the temperature during plastic deformation, and the holding time. Further, wrinkles are generated when the carcass band is expanded to a large diameter of 1.4 Y from Examples 4 and 5 , but as shown in Examples 6 and 7 , the generation of wrinkles is avoided by adjusting the temperature to be higher. I understand that I can do it.

It is a fragmentary sectional view showing an example of the pneumatic tire manufactured by the manufacturing method of the pneumatic tire of the present invention. It is explanatory drawing which shows the process of shape | molding a carcass band in one Embodiment of the manufacturing method of the pneumatic tire of this invention. It is explanatory drawing which shows the process of plastically deforming an inner liner layer in one Embodiment of the manufacturing method of the pneumatic tire of this invention. It is explanatory drawing which shows the process of reducing the diameter of the carcass band which has the inner liner layer plastically deformed in one Embodiment of the manufacturing method of the pneumatic tire of this invention. It is explanatory drawing which shows the process of arrange | positioning a tread ring in one Embodiment of the manufacturing method of the pneumatic tire of this invention. In one embodiment of the manufacturing method of the pneumatic tire of the present invention, it is an explanatory view showing the process of forming a green tire by expanding the diameter of a carcass band and crimping it to a tread ring.

Explanation of symbols

4 Carcass layer 7 Belt layer 8 Tread rubber layer 10 Inner liner layer 13 Carcass band 14 Tread ring 21 Molding drum 22 Shaping drum 23 Chamber

Claims (4)

A green tire is formed by expanding a carcass band having an inner liner layer made of a thermoplastic elastomer composition in which a thermoplastic resin or a thermoplastic resin component and an elastomer component are blended, and pressing the carcass band on the inner peripheral side of the tread ring. In the pneumatic tire manufacturing method, the carcass band is inflated so that the outer diameter thereof is in a range of 1.1 to 1.4 times the inner diameter of the tread ring, and the state is maintained for a predetermined time. After the inner liner layer is plastically deformed, the expanded carcass band is once reduced in diameter until the outer diameter becomes smaller than the inner diameter of the tread ring, and the once reduced carcass band is expanded in the tread ring. A method of manufacturing a pneumatic tire that is made to have a diameter and press-bonded to the inner peripheral side of the tread ring. The method for manufacturing a pneumatic tire according to claim 1 , wherein the holding time T (seconds) is 120 seconds or less. The method for producing a pneumatic tire according to claim 2 , wherein the holding time T (seconds) is 1 second ≤ T ≤ 120 seconds. The method for manufacturing a pneumatic tire according to any one of claims 1 to 3 , wherein the inner liner layer is plastically deformed in an atmosphere at a temperature of 20 to 100 ° C.