JP2019119421A - Pneumatic tire - Google Patents

Abstract

To provide a pneumatic tire that has a laminate of a film of a thermoplastic elastomer composition containing a thermoplastic resin or a blend of the thermoplastic resin and an elastomer, and a rubber composition, which prevents occurrence of cracks and peeling in a lap-spliced part of the laminate and can improve durability.SOLUTION: A laminate 1 is formed of a film 2 of a thermoplastic elastomer composition containing a thermoplastic resin or a blend of the thermoplastic resin and an elastomer and a rubber composition 3 laminated on at least one side of the film 2, in which ends in a tire circumferential direction of the laminate 1 overlap each other at one portion on the tire circumference to form a lap-spliced part 4, and an interlayer rubber layer 3A formed of the rubber composition 3 is interposed between layers of the film 2 in the lap-spliced part 4, a lap length L in the tire circumferential direction of the laminate 1 in the lap-spliced part 4 satisfies expression (1).SELECTED DRAWING: Figure 2

Description

  The present invention relates to a pneumatic tire, and more particularly, to a pneumatic tire having a laminate of a film of a thermoplastic elastomer composition comprising a thermoplastic resin or a blend of a thermoplastic resin and an elastomer and a rubber composition. The present invention relates to a pneumatic tire capable of preventing the occurrence of a crack and peeling at a lap splice portion of a laminate of the tire and improving the durability.

  It has been proposed to use a film formed of a thermoplastic resin or a thermoplastic elastomer composition consisting of a thermoplastic resin and an elastomer as a tire component such as an inner liner layer. Such a film is subjected to a tire manufacturing process as a laminate in which a rubber composition for adhesion is laminated on at least one side, and a lap splice portion is formed by overlapping end portions of the laminate in the tire circumferential direction. (See, for example, Patent Documents 1 to 3).

  However, when the lap splice portion is formed by overlapping the end portions in the tire circumferential direction of the laminate as described above, a structure in which an interlayer rubber layer is interposed between layers of the film is formed in the lap splice portion. When the tire is deformed during traveling, large distortion occurs between the rubber and the interlayer rubber layer of the film having different rigidity, and there is a problem that cracking and peeling easily occur starting from the lap splice portion. In particular, in the case of using the above-described film as an inner liner layer in a heavy-duty pneumatic tire for bus, truck, etc., it is necessary to make the film thicker according to the air pressure, so that distortion occurring in the lap splice portion becomes large And peeling is likely to occur.

JP 2012-240658 A International Publication No. 2016/063785 International Publication No. 2016/2060128

  The object of the present invention is to provide a pneumatic tire comprising a laminate comprising a film of a thermoplastic elastomer composition comprising a thermoplastic resin or a blend of a thermoplastic resin and an elastomer and a rubber composition, wherein the pneumatic tire comprises the laminate An object of the present invention is to provide a pneumatic tire capable of preventing the occurrence of cracks and peeling at a lap splice portion and improving the durability.

A pneumatic tire for achieving the above object comprises a film of a thermoplastic elastomer composition comprising a thermoplastic resin or a blend of a thermoplastic resin and an elastomer, and a rubber composition laminated on at least one side of the film. And the end portions of the laminate in the tire circumferential direction are overlapped at at least one place on the tire circumference to form a lap splice portion, and the rubber is interposed between the films in the lap splice portion. In a pneumatic tire in which an interlayer rubber layer made of a composition is interposed, a wrap length L of the laminate in the wrap splice portion in the tire circumferential direction satisfies the following formula (1).
L ≧ 0.5 × Gf × Mf / (Gg × Mg) (1)
However, Gf: average thickness [mm] of the film at the lap splice portion
Gg: average thickness [mm] of the interlayer rubber layer at the lap splice portion
Mf: Modulus at 20% elongation of the film [MPa]
Mg: Modulus [MPa] at 20% elongation of the interlayer rubber layer

  The inventors of the present invention conducted intensive studies on a pneumatic tire provided with a laminate comprising a film of a thermoplastic elastomer composition comprising a thermoplastic resin or a blend of a thermoplastic resin and an elastomer and a rubber composition, With regard to the lap length necessary to prevent cracking and peeling at the lap splice portion of the above laminate, a relational expression based on the average thickness of the film and the interlayer rubber layer and the modulus at 20% elongation is derived, It has come to an end.

  The present invention comprises a laminate of a film of a thermoplastic elastomer composition comprising a thermoplastic resin or a blend of a thermoplastic resin and an elastomer, and a rubber composition laminated on at least one side of the film, The end portions of the laminate in the tire circumferential direction are overlapped at at least one place on the tire circumference to form a lap splice portion, and an interlayer rubber layer made of a rubber composition is interposed between layers of the film in the lap splice portion. In the pneumatic tire, when the lap length L of the laminate in the lap splice portion in the tire circumferential direction satisfies the above equation (1), the required minimum lap length L in the tire circumferential direction at the lap splice portion of the laminate To prevent the occurrence of cracks and peeling at the lap splice and improve the durability. It can be. Therefore, even in a heavy load pneumatic tire for bus, truck, etc., it is possible to prevent the occurrence of cracking and peeling at the lap splice portion, and to effectively improve the durability.

  In the present invention, the average thickness Gf of the film at the wrap splice portion is preferably 0.01 mm to 0.50 mm. Thereby, the defect at the time of shaping | molding can be suppressed and the deterioration of uniformity can be prevented.

In the present invention, the average thickness Gf [mm] of the film at the lap splice and the maximum air pressure P [kPa] of the tire satisfy the relationship of P / 20 × 10 ⁻³ ≦ Gf ≦ P / 2 × 10 ⁻³ Is preferred. Thereby, the failure of the lap splice portion can be effectively suppressed.

  In the present invention, the modulus Mf at 20% elongation of the film is preferably 2.0 MPa to 20.0 MPa. Thereby, excessive elongation and non-uniform expansion at the time of film formation can be suppressed.

  In the present invention, the average thickness Gg of the interlayer rubber layer in the lap splice portion is preferably 0.10 mm to 1.00 mm. Thereby, the defect at the time of shaping | molding can be suppressed and the deterioration of uniformity can be prevented.

  In the present invention, the modulus Mg at 20% elongation of the interlayer rubber layer is preferably 0.1 MPa to 1.0 MPa. Thus, both the steering stability of the pneumatic tire and the improvement of the riding comfort can be achieved.

  In the present invention, at least one end of the film preferably has a tapered shape, and the tip angle α preferably satisfies the relationship 45 ° ≦ α <90 °. As a result, the durability of the film can be improved and defects during molding can be suppressed.

  In the present invention, the laminate is preferably an air permeation preventive layer. By using the above laminate for the air permeation preventive layer, an excellent air permeation preventive performance can be obtained.

  In the present invention, the modulus [MPa] at 20% elongation of the film and the interlayer rubber layer is measured in accordance with JIS K-6251: 2010. That is, a film and an interlayer rubber layer are collected from a vulcanized pneumatic tire, or a film and an interlayer rubber layer having a heat history equivalent to vulcanization are produced. For each of the film and interlayer rubber layer thus collected or punched, a JIS No. 3 dumbbell-shaped test piece is punched out, and a tensile test is conducted under conditions of a tensile speed of 500 mm / min and a temperature of 20 ° C. It is the value which measured stress.

It is a partially broken perspective view showing an example of an embodiment of a pneumatic tire of the present invention, and explains the physical relationship in a tire of a lap splice part. It is a sectional view showing an example of an embodiment of a lap splice part in a layered product of a pneumatic tire of the present invention, and expanding and showing a part of tire equatorial section. (A)-(c) is the modification which expands and shows the tip part of the film which constitutes the layered product of the pneumatic tire of the present invention, and (a)-(c) is a sectional view of each modification. .

  Hereinafter, the configuration of the present invention will be described in detail with reference to the attached drawings. FIG. 1 shows an example of an embodiment of the pneumatic tire of the present invention. FIG. 2 shows an example of an embodiment of a lap splice portion in a laminate of a pneumatic tire according to the present invention. In FIGS. 1 and 2, an arrow Tc indicates a tire circumferential direction, and an arrow Tw indicates a tire width direction.

  In the pneumatic tire illustrated in FIG. 1, sidewall portions 12 and bead portions 13 are provided so as to be connected to the left and right of the tread portion 11. On the inner side of the tire, a carcass layer 14 which is a skeleton of the tire is provided so as to straddle between the left and right bead portions 13 in the tire width direction, and around the bead cores 16 disposed in each bead portion 13 It has been folded outwards. A two-layered belt layer 15 made of a steel cord is provided on the outer peripheral side of the carcass layer 14 corresponding to the tread portion 11. An inner liner layer 10 (air permeation preventing layer 10) is disposed on the inner side of the carcass layer 14, and the lap splice portion 4 extends in the tire width direction.

  In the pneumatic tire shown in FIG. 2, the laminate 1 is used as the inner liner layer 10 (the air permeation preventive layer 10), and the end portions of the laminate 1 in the tire circumferential direction are overlapped with each other at at least one location on the tire circumference. And has a lap splice structure. The laminate 1 is formed on at least a two-layer structure of a rubber composition 3 by laminating the film 2 and at least one side thereof. The film 2 is a film of a thermoplastic elastomer composition comprising a thermoplastic resin or a blend of a thermoplastic resin and an elastomer. The rubber composition 3 laminated on the film 2 is vulcanized and adhered to the film 2. In the wrap splice portion 4, an interlayer rubber layer 3 </ b> A made of the rubber composition 3 is present between the layers of the film 2. In FIG. 2, the cross sections of the film 2 and the main body of the rubber composition 3 are drawn in a straight line for easy understanding.

  When a single film 2 is used when the laminate 1 is to be lap-spliced, both ends of the film 2 in the tire circumferential direction are lap-spliced via the rubber composition 3 to form an annular shape. Alternatively, when a plurality of films 2 are used, the ends in the tire circumferential direction of the respective films 2 are lap-spliced through the rubber composition 3 so that the respective films 2 are joined together to form an annular shape as a whole. It is formed as Further, as shown in FIG. 2, when the laminate 1 has a three-layer structure of the film 2 and the rubber composition 3 laminated on both sides thereof, the end portions of the laminate 1 in the tire circumferential direction are The bonding is a structure in which the films 2 overlap with each other through the rubber composition 3, and the rubber-rubber bonds by vulcanization, so the adhesion is large.

In the pneumatic tire, the wrap length L in the tire circumferential direction of the laminate 1 in the wrap splice portion 4 is configured to satisfy the following formula (1). In the following formula (1), Gf is the average thickness [mm] of the film 2 at the wrap splice portion 4, Gg is the average thickness [mm] of the interlayer rubber layer 3A at the wrap splice portion 4, and Mf is the film Modulus [MPa] at 20% elongation of 2 and Mg is modulus [MPa] at 20% elongation of the interlayer rubber layer 3A. In the following formula (1), as the ratio of Gf × Mf of film 2 to Gg × Mg of interlayer rubber layer 3A increases (as the difference in rigidity between film 2 and interlayer rubber layer 3A increases), the lap length L is It indicates that you need to make it longer. The wrap length L is the length in the circumferential direction of the tire from the tip of one end of the film 2 to the tip of the other end, and the average thickness of the film 2 at the wrap splice portion 4 is Gf is a measurement of the average thickness at both ends of the film 2 in the tire circumferential direction.
L ≧ 0.5 × Gf × Mf / (Gg × Mg) (1)

  In the pneumatic tire described above, a film 2 of a thermoplastic elastomer composition comprising a thermoplastic resin or a blend of a thermoplastic resin and an elastomer and a rubber composition 3 laminated on at least one side of the film 2 The end portions of the laminate 1 in the tire circumferential direction are overlapped at at least one place on the tire circumference to form a lap splice portion 4, and the lap splice portion 4 is formed between layers of the film 2. In the pneumatic tire in which the interlayer rubber layer 3A made of the rubber composition 3 is interposed, the lap length L of the laminate 1 at the lap splice portion 4 in the circumferential direction of the tire satisfies the above equation (1). Since the minimum required circumferential lap length L at the lap splice portion 4 is secured, the clasp at the lap splice portion 4 To prevent click and peeling can be improved durability. Therefore, even in a heavy load pneumatic tire for a bus, a truck, etc., it is possible to prevent the occurrence of cracks and peeling at the lap splice portion 4 and to improve the durability effectively.

  In the pneumatic tire, the upper limit of the wrap length L in the tire circumferential direction of the laminate 1 in the wrap splice portion 4 is preferably set to L + 10 mm, and more preferably to L + 5 mm. Also, in the vicinity of the lap splice portion 4 of the laminate 1 (in the region of 10 mm on both sides from the lap splice portion 4 to the tire circumferential direction including the lap splice portion 4), other tire constituent members (for example, carcass layer etc.) It is preferable that there is no lap splice portion in which the end portions in the tire circumferential direction are overlapped with each other.

  In the pneumatic tire, the average thickness Gf (see FIG. 2) of the film 2 at the wrap splice portion 4 is preferably 0.01 mm to 0.50 mm. By appropriately setting the average thickness Gf of the film 2 as described above, it is possible to suppress a defect at the time of molding and to prevent deterioration of uniformity. Here, when the average thickness Gf of the film 2 is thinner than 0.01 mm, the film 2 tends to be wrinkled at the time of molding, and conversely, when it is thicker than 0.50 mm, the uniformity tends to be deteriorated.

Further, the average thickness Gf [mm] of the film 2 at the lap splice portion 4 and the maximum air pressure P [kPa] of the tire satisfy the relationship of P / 20 × 10 ⁻³ ≦ Gf ≦ P / 2 × 10 ⁻³ Is preferred. By appropriately setting the average thickness Gf of the film 2 with respect to the maximum air pressure P of the tire as described above, failure of the wrap splice portion 4 can be effectively suppressed. Here, when the average thickness Gf of the film 2 is thinner than P / 20 × 10 ^-3 , the air leak performance of the film 2 is deteriorated and the rubber inside is easily oxidized and deteriorated, conversely, P / 2 × 10 ^-3. If the thickness is thicker than this, the lap splice portion 4 is likely to break down when passing over a curb or the like during traveling and subjected to excessive distortion.

  Furthermore, the modulus Mf at 20% elongation of the film 2 is preferably 2.0 MPa to 20.0 MPa. By appropriately setting the modulus Mf at 20% elongation of the film 2 as described above, it is possible to suppress excessive elongation and nonuniform expansion at the time of forming the film 2. Here, when the modulus Mf at 20% elongation of the film 2 is lower than 2.0 MPa, the film 2 is excessively expanded at the time of forming and it becomes easy to wrinkle, conversely, when it is higher than 20.0 MPa, the film 2 at the time of forming It does not swell uniformly, and the uniformity tends to deteriorate.

  In the pneumatic tire, the average thickness Gg (see FIG. 2) of the interlayer rubber layer 3A in the wrap splice portion 4 is preferably 0.10 mm to 1.00 mm. By appropriately setting the average thickness Gg of the interlayer rubber layer 3A in this manner, it is possible to suppress a defect at the time of molding and to prevent deterioration of uniformity. Here, when the interlayer rubber layer 3A is thinner than 0.10 mm, it tends to be wrinkled during molding, and conversely, when it is thicker than 1.00 mm, the uniformity tends to be deteriorated.

  The modulus Mg at 20% elongation of the interlayer rubber layer 3A is preferably 0.1 MPa to 1.0 MPa. By appropriately setting the modulus Mg at 20% elongation of the interlayer rubber layer 3A in this manner, it is possible to achieve both the steering stability of the pneumatic tire and the improvement of the riding comfort. Here, when the modulus Mg at 20% elongation of the interlayer rubber layer 3A is lower than 0.1 MPa, the steering stability of the pneumatic tire is easily deteriorated, and conversely, when it is higher than 1.0 MPa, the riding comfort is deteriorated. Tend.

  FIGS. 3 (a) to 3 (c) are modified examples showing the tip of the film constituting the laminate of the pneumatic tire of the present invention in an enlarged manner. In any of FIGS. 3A to 3C, at least one end of the film 2 has a tapered shape. More specifically, in FIG. 3A, one side of the tip of the film 2 has an inclined shape, and in FIG. 3B, both sides of the tip of the film 2 have an inclined shape. In FIG. 3C, the tip of the film 2 has a semicircular shape. At this time, it is preferable that the tip angle α of the film 2 satisfy the relationship 45 ° ≦ α <90 °. As described above, since the end portion of the film 2 has a tapered shape, a high stress relaxation effect can be obtained, and further, the durability of the film 2 can be improved by appropriately setting the tip angle α. While improving it, the defect at the time of shaping | molding can be suppressed. Here, if the angle α of the end portion of the film 2 is smaller than 45 °, the film 2 is likely to be wrinkled when it is formed. In the case of FIG. 3C, the tip angle α of the film 2 is an angle formed by a line connecting a point P1 at which the thickness of the tip of the film 2 starts to change and the tip P2 of the film 2.

  In the present invention, the film 2 is a film of a thermoplastic resin or a film of a thermoplastic elastomer composition comprising a blend of a thermoplastic resin and an elastomer.

  Examples of thermoplastic resins that can be used for the film 2 include polyamide resins [eg, nylon 6 (N 6), nylon 66 (N 66), nylon 46 (N 46), nylon 11 (N 11), nylon 12 (N 12) , Nylon 610 (N610), nylon 612 (N 612), nylon 6/66 copolymer (N6 / 66), nylon 6/66/610 copolymer (N6 / 66/610), nylon MXD6 (MXD6), nylon 6T, nylon 9T, nylon 6 / 6T copolymer, nylon 66 / PP copolymer, nylon 66 / PPS copolymer] and their N-alkoxyalkylated compounds [e.g., methoxymethylated nylon 6, nylon 6/6 Methoxymethylated copolymer of 610 copolymer, methoxymethylated compound of nylon 612, polyethylene Tellurium resin (eg, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyethylene isophthalate (PEI), PET / PEI copolymer, polyarylate (PAR), polybutylene naphthalate (PBN), liquid crystalline polyester, Aromatic polyesters such as polyoxyalkylene diimido diacid / polybutylene terephthalate copolymers], polynitrile resins [eg, polyacrylonitrile (PAN), polymethacrylonitrile, acrylonitrile / styrene copolymer (AS), (meth) Acrylonitrile / styrene copolymer, (meth) acrylonitrile / styrene / butadiene copolymer], polymethacrylate resin [eg, polymethyl methacrylate (PMMA), polyethyl methacrylate], poly Nil-based resins [eg polyvinyl acetate, polyvinyl alcohol (PVA), vinyl alcohol / ethylene copolymer (EVOH), polyvinylidene chloride (PVDC), polyvinyl chloride (PVC), vinyl chloride / vinylidene chloride copolymer, Vinylidene chloride / methyl acrylate copolymer, vinylidene chloride / acrylonitrile copolymer (ETFE)], cellulose resin [eg, cellulose acetate, cellulose acetate butyrate], fluorine resin [eg, polyvinylidene fluoride (PVDF), poly fluoride Vinyl (PVF), polychlorofluoroethylene (PCTFE), tetrafluoroethylene / ethylene copolymer], imide resin [eg, aromatic polyimide (PI)], etc. can be used.

  Among them, polyester resins and polyamide resins are preferable in terms of physical properties, processability, handleability and the like.

  In addition, a blend of a thermoplastic resin and an elastomer (a thermoplastic elastomer composition) capable of constituting the film 2 has a structure in which the elastomer is dispersed as a discontinuous phase in a matrix of the thermoplastic resin. By adopting such a structure, it is possible to obtain the same moldability as a thermoplastic resin. Among thermoplastic resins and elastomers constituting the thermoplastic elastomer composition, as the thermoplastic resin, those described above can be used. Examples of the elastomer constituting the thermoplastic elastomer composition include diene rubbers and hydrogenated products thereof [eg, natural rubber (NR), isoprene rubber (IR), epoxidized natural rubber, styrene butadiene rubber (SBR), butadiene Rubber (BR, high cis BR and low cis BR), nitrile rubber (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 [eg Br-IIR, CI-IIR, brominated isobutylene- p-methylstyrene copolymer (BIMS), chloroprene Rubber (CR), hydrin 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 silicone rubber], sulfur-containing rubber [eg, polysulfide rubber], fluororubber [eg, vinylidene fluoride rubber, fluorine-containing vinyl ether rubber, tetrafluoroethylene-propylene rubber, fluorine-containing silicon rubber] Rubber, fluorine-containing phosphazene type rubber], thermoplastic elastomer [eg styrene type elastomer, olefin type elastomer, ester type elastomer, urethane type elastomer, polyamido type elastomer] etc. is preferably used Door can be.

  In particular, when blending a plurality of elastomers, it is preferred that 50% by weight or more of them is a halogenated butyl rubber, a brominated isobutylene paramethylstyrene copolymer rubber or a maleic anhydride modified ethylene alpha olefin copolymer rubber, It is preferable in that it can be increased to be flexible and durable from low temperature to high temperature.

  In addition, 50% by weight or more of the thermoplastic resin in the thermoplastic elastomer composition is nylon 11, nylon 12, nylon 6, nylon 66, nylon 6/66 copolymer, nylon 6/12 copolymer, nylon 6/12 Excellent durability can be obtained by being any of 10 copolymers, nylon 4/6 copolymer, nylon 6/66/12 copolymer, aromatic nylon, and ethylene / vinyl alcohol copolymer It is possible and preferable.

  When the thermoplastic elastomer composition is prepared by combining the specific thermoplastic resin and the elastomer described above, if the compatibility between the two is insufficient, the third component is compatibilized using a suitable compatibilizer. be able to. By mixing the compatibilizer with the blend system of the thermoplastic resin and the elastomer, the interfacial tension between the thermoplastic resin and the elastomer decreases, and as a result, the particle size of the elastomer forming the dispersed phase becomes finer. The characteristics of both components will be expressed more effectively. As such compatibilizer, generally, a copolymer having a structure of one or both of a thermoplastic resin and an elastomer, or an epoxy group, a carbonyl group, a halogen group or an amino group capable of reacting with the thermoplastic resin or elastomer. The structure of a copolymer having an oxazoline group, a hydroxyl group or the like can be taken. These may be selected according to the type of thermoplastic resin and elastomer to be blended, but among those commonly used, 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 phenoxy, etc. can be mentioned. The blending amount of the compatibilizer is not particularly limited, but 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).

  In the thermoplastic elastomer composition, the composition ratio of the thermoplastic resin to the elastomer is not particularly limited. For example, the composition ratio may be appropriately determined so that the elastomer has a structure dispersed as a discontinuous phase in the matrix of the thermoplastic resin. The composition ratio of the thermoplastic resin to the elastomer is preferably 90/10 to 20/80, more preferably 80/20 to 30/70, in terms of the weight ratio of thermoplastic resin / elastomer.

  In the present invention, a thermoplastic resin, or a thermoplastic elastomer composition obtained by blending a thermoplastic resin and an elastomer, is, for example, other than the above-mentioned compatibilizer within the range not impairing the properties necessary for constituting the film 2 Also, other polymers can be mixed. The purpose of mixing other polymers is to improve the molding processability of the material, to improve the heat resistance, to reduce the cost, etc. The materials used for this include, for example, polyethylene (PE), polypropylene ( PP), polystyrene (PS), ABS, SBS, polycarbonate (PC) etc. can be exemplified.

  In addition, fillers (such as calcium carbonate, titanium oxide and alumina), reinforcing agents such as carbon black and white carbon, softeners, plasticizers, processing aids, pigments, dyes, etc., which are generally incorporated into polymer formulations The inhibitor and the like can be optionally blended as long as the required properties of the film 2 are not impaired.

  Also, the elastomer blended with the thermoplastic resin can be dynamically vulcanized upon mixing with the thermoplastic resin. Vulcanizing agents, vulcanizing assistants, vulcanizing conditions (temperature, time) and the like in the case of dynamically vulcanizing may be suitably determined in accordance with the composition of the elastomer to be added, and are not particularly limited.

  The fact that the elastomer in the thermoplastic resin composition is dynamically vulcanized in this way means that the resulting thermoplastic elastomer composition contains the vulcanized elastomer, so that it is resistant to external deformation. There is a force (elasticity), and the effect of the present invention can be increased, which is preferable.

  As a vulcanizing agent, a general rubber vulcanizing agent (crosslinking agent) can be used. Specifically, examples of sulfur-based vulcanizing agents include powdered sulfur, precipitated sulfur, highly dispersible sulfur, surface-treated sulfur, insoluble sulfur, dimorpholine disulfide, alkylphenol disulfide, etc. An amount of 4 phr (herein, “phr” refers to parts by weight per 100 parts by weight of the elastomer component. The same applies hereinafter) can be used.

  Further, as the organic peroxide type vulcanizing agent, benzoyl peroxide, t-butyl hydroperoxide, 2,4-dichlorobenzoyl peroxide, 2,5-dimethyl-2,5-di (t-butyl peroxide) Examples include oxy) hexane, 2,5-dimethylhexane-2,5-di (peroxyl benzoate) and the like, and for example, about 1 to 20 phr can be used.

  Furthermore, as a phenol resin-based vulcanizing agent, a brominated compound of an alkyl phenol resin, a mixed crosslinking system containing a halogen donor such as tin chloride or chloroprene, and an alkyl phenol resin can be exemplified. Can.

  Other examples include zinc flower (about 5 phr), magnesium oxide (about 4 phr), liserge (about 10 to 20 phr), p-quinone dioxime, p-dibenzoyl quinone dioxime, tetrachloro-p-benzoquinone, poly-p- Examples include dinitrosobenzene (about 2 to 10 phr) and methylenedianiline (about 0.2 to 10 phr).

  In addition, if necessary, a vulcanization accelerator may be added. As the vulcanization accelerator, general vulcanization accelerators such as aldehyde / ammonia type, guanidine type, thiazole type, sulfenamide type, thiuram type, dithioate type, thiourea type, etc. About 2 phr can be used.

  The rubber material constituting the rubber composition 3 includes diene rubbers such as natural rubber, isoprene rubber, epoxidized natural rubber, styrene butadiene rubber, hydrogenated styrene butadiene rubber, ethylene propylene rubber, maleic acid modified ethylene propylene An olefin rubber such as rubber can be preferably used.

  And in order to improve the adhesiveness with the rubber composition 3 which adjoins the said film 2, it is good to interpose an adhesive layer and to laminate | stack it. As polymers constituting the adhesive layer, acrylate copolymers such as ultra high molecular weight polyethylene having a molecular weight of 1,000,000 or more, preferably 3,000,000 or more, an ethylene ethyl acrylate copolymer, an ethylene methyl acrylate resin, an ethylene acrylic acid copolymer and the like And its maleic anhydride adduct, polypropylene and its maleic acid modified product, ethylene propylene copolymer and its maleic acid modified product, polybutadiene resin and its maleic anhydride modified product, styrene-butadiene-styrene copolymer, styrene Ethylene-butadiene-styrene copolymer, fluorine-based thermoplastic resin, polyester-based thermoplastic resin, etc. are preferably used.

  Although embodiment mentioned above demonstrated the case where the laminated body 1 was used for the inner liner layer 10 (air permeation prevention layer 10), the laminated body 1 can also be applied as a reinforcement member. In particular, when the laminate 1 is used for the air permeation prevention layer, excellent air permeation prevention performance can be obtained.

  A film of thermoplastic elastomer composition comprising a blend of a thermoplastic resin and an elastomer, and a rubber laminated on both sides of the film, with a tire size of 195 / 65R15 (for passenger car) and 275 / 70R22.5 (for heavy load) The laminate comprises the composition and the end portions of the laminate in the circumferential direction of the laminate are overlapped to form a lap splice, and an interlayer rubber layer comprising a rubber composition is interposed between layers of the film in the lap splice. Tire type, lap length L, average film thickness Gf, film modulus Mf, interlayer rubber layer average thickness Gg, interlayer rubber layer modulus Mg 0.5 × Gf × Mf / (Gg x Mg), tires of Comparative Examples 1 to 3 and Examples 1 to 8 in which the tip angle α of the film is varied as shown in Table It was.

  In the tire of Comparative Example 1 and Examples 1, 2, 6, 8 (Modulus Mf of the film of Table 1 = 20.0), the films were nylon 6/66 copolymer (N6 / 66) and bromine. A thermoplastic elastomer composition comprising a fluorinated isobutylene-p-methylstyrene copolymer (BIMS) in a weight ratio of 75/25, and Comparative Examples 2, 3 and Examples 4, 5, 7 (the films of Table 1 In the tire of modulus Mf = 10.0), the film is a thermoplastic elastomer composition comprising N6 / 66 and BIMS in a weight ratio 50/50, and the modulus Mf of the film of table 1 Mf = 2.0 In the tire), the film is a thermoplastic elastomer composition comprising N6 / 66 and BIMS in a weight ratio of 30/70. Moreover, in each test tire, it was made common that a rubber composition is a rubber composition which has natural rubber and styrene butadiene rubber as a main component.

  The durability of each of these test tires was evaluated by the following test method, and the results are also shown in Table 1.

durability:
Each test tire is assembled to either rim size 15 × 6 JJ (for passenger car) or rim size 22.5 × 7.50 (for heavy load), so that the tire internal pressure is 240 kPa (for passenger car) or 900 kPa (for heavy load) Was filled. The tire was subjected to an indoor drum test machine and loaded at 120% of the maximum load capacity specified by JATMA, and traveled 20,000 km at a speed of 80 km / h (for passenger car) or 50 km / h (for heavy load). Thereafter, the lap splice portion of the laminate was visually observed to confirm the occurrence of a crack, and when it occurred, the length [mm] of the crack was measured.

  As can be seen from Table 1, in the tires of Examples 1 to 8, the lap length L of the laminate in the tire circumferential direction was set to be equal to or greater than the length obtained from the equation (1) defined in the present invention. The occurrence of cracking and peeling at the lap splice portion can be prevented, and the durability is improved compared to the tires of Comparative Examples 1 to 3.

Reference Signs List 1 laminated body 2 film 3 rubber composition 3A interlayer rubber layer 4 wrap splice portion 10 inner liner layer (air permeation preventive layer)
11 tread portion 12 sidewall portion 13 bead portion 14 carcass layer 15 belt layer 16 bead core L wrap length

Claims (8)

A laminate comprising a film of a thermoplastic elastomer composition comprising a thermoplastic resin or a blend of a thermoplastic resin and an elastomer, and a rubber composition laminated on at least one side of the film; The end portions in the circumferential direction of the tire are overlapped at at least one place on the tire circumference to form a lap splice portion, and in the lap splice portion, there is air containing an interlayer rubber layer composed of the rubber composition between layers of the film. In a tire, a pneumatic tire characterized in that a wrap length L of a tire circumferential direction of the layered product in the wrap splice portion satisfies the following formula (1).
L ≧ 0.5 × Gf × Mf / (Gg × Mg) (1)
However, Gf: average thickness [mm] of the film at the lap splice portion
Gg: average thickness [mm] of the interlayer rubber layer at the lap splice portion
Mf: Modulus at 20% elongation of the film [MPa]
Mg: Modulus [MPa] at 20% elongation of the interlayer rubber layer   The pneumatic tire according to claim 1, wherein an average thickness Gf of the film at the wrap splice portion is 0.01 mm to 0.50 mm. It is satisfied that the average thickness Gf [mm] of the film and the maximum air pressure P [kPa] of the tire at the lap splice portion satisfy the relationship of P / 20 × 10 ⁻³ ≦ Gf ≦ P / 2 × 10 ⁻³ The pneumatic tire according to claim 1 or 2, characterized in.   The pneumatic tire according to any one of claims 1 to 3, wherein a modulus Mf at 20% elongation of the film is 2.0 MPa to 20.0 MPa.   The pneumatic tire according to any one of claims 1 to 4, wherein an average thickness Gg of the interlayer rubber layer in the lap splice portion is 0.10 mm to 1.00 mm.   The pneumatic tire according to any one of claims 1 to 5, wherein a modulus Mg at 20% elongation of the interlayer rubber layer is 0.1 MPa to 1.0 MPa.   The air-filled according to any one of claims 1 to 6, wherein at least one end of the film has a tapered shape, and the tip angle α satisfies the relationship 45 ° ≦ α <90 °. tire.   The pneumatic tire according to any one of claims 1 to 7, wherein the laminate is an air permeation preventive layer.

Images