JPH1081108A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the weight of a tire without causing any trouble such as a defect at its manufacture and deteriorating the protection of its bead part at its finishing. SOLUTION: A pneumatic tire comprises an air-permeation prevention layer 3 for substantially covering the inner periphery of the tire made of a film of a thermoplastic elastomer composition including a thermoplastic resin having an air permeation coefficient up to 25×10<-12> cc.cm/cm<2> .sec.cmHg or including a blend of such a thermoplastic resin and elastomer, and rubber finishing layers 6 arranged to hold the air-permeation protection layer 3 between them and a tire carcass layer 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic tire, and more particularly, to a pneumatic tire having a reduced weight without causing a manufacturing failure and without impairing protection of a bead portion of a finishing layer.

[0002]

2. Description of the Related Art Conventionally, when halogenated butyl rubber is used as a material for preventing air permeation of a tire, if it is directly attached to a carcass, the butyl rubber having a large hysteresis loss hardly enters a gap between carcass cords, so that rolling resistance is deteriorated. The tie rubber with a small hysteresis loss was inserted between the tie rubbers.
There is a problem that the tire weight increases because the diameter is equal to or more than mm. Therefore, it has been proposed to use a film having a lower air permeability than butyl rubber to reduce the thickness and to reduce the weight (for example, see Japanese Patent Application Laid-Open No. Hei 5-3299961). However, with the conventional tire structure, the air permeation prevention layer 3 made of butyl rubber is simply replaced with a film, and a textile finishing obtained by rubberizing a cord of nylon or the like is used for finishing (hereinafter referred to as textile finishing). Then, a force for returning the folded finishing layer 5 to its original shape acts (see the arrow in FIG. 2A), and the film before vulcanization does not have a strong adhesive force like rubber, so that the tire There is a manufacturing problem in that the finishing layer 5 peels off from the film 3 during molding (see FIG. 2B) or peels off between the film 3 and the carcass layer 2 (FIG. 2).
(C)). Of course, if the finishing layer 5 is removed,
Although the problem of peeling at the time of molding can be avoided, the finishing layer 5 has a function of protecting the bead portion when assembling the tire to the rim and sealing the bead portion.
It cannot be excluded from the tire structure.

[0003]

SUMMARY OF THE INVENTION Accordingly, the present invention solves the above-mentioned problems of the conventional pneumatic tires, without the problem of failure during manufacturing, and without impairing the protection of the bead portion of the finishing. It is an object of the present invention to provide a pneumatic tire capable of reducing the weight of a tire.

[0004]

According to the present invention, there is provided a thermoplastic resin having an air permeability coefficient of 25 × 10 ⁻¹² [cc · cm / cm ² · sec · cmHg] or less, or a blend of a thermoplastic resin and an elastomer. A pneumatic tire comprising a film of a thermoplastic elastomer composition containing: a pneumatic tire having an air permeation prevention layer substantially covering the inner surface of the tire, and the air permeation prevention layer disposed outside the finishing layer, or a rubber finishing. The pneumatic tire used, or the pneumatic tire using a textile finishing with a small number of deniers or cords, or the pneumatic tire with the air permeation prevention layer wound or wound on the bead core, or the air permeation prevention layer and finishing Pneumatic tire with non-wrapping structure, or adhesive between air permeation prevention layer and adjacent layer Is provided.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be further described below with reference to the drawings. FIG. 1 is a half-sectional view in the meridian direction illustrating a typical example of a pneumatic tire. In FIG. 1, a carcass layer 2 is mounted between a pair of left and right bead cores 1, 1.
Is provided. In the present invention, the air permeation preventing layer 3 is composed of a film of a thermoplastic elastomer composition having a specific air permeation coefficient. The position of the air permeation prevention layer 3 is not necessarily limited to this position. In FIG. 1, reference numeral 4 denotes a sidewall.

According to the first aspect of the present invention, for example, FIG.
As an example, a film of a thermoplastic resin having a lower air permeability than a conventional butyl rubber or a thermoplastic elastomer composition containing a blend of a thermoplastic resin and an elastomer is used for the air permeation prevention layer 3 to form a layer of butyl rubber or more. In addition to maintaining air leakage resistance, a rubber finishing layer (hereinafter referred to as a gum finishing layer) 6 is provided between the carcass layer 2 and a rubber finishing layer (hereinafter referred to as a gum finishing layer) 6 instead of a conventional textile finishing layer using a cord such as nylon. 3
Between them. Gum finishing includes diene rubbers (eg, natural rubber, polyisoprene rubber, styrene-butadiene rubber, styrene-butadiene copolymer rubber, and polybutadiene rubber (high cis BR and low cis B).
R) and the like can be exemplified by a rubber composition obtained by adding a compounding agent such as carbon black, process oil, and vulcanizing agent. The air permeation preventing layer 3 may be wound around a bead core 1 as shown in FIG.

The conventional textile finishing layer is
There is a problem that the actual contact area becomes small due to the unevenness of the surface due to the thread of the cord, but since the gum finishing layer has a smooth surface, the actual contact area is large, and it can exhibit an effective adhesive force, This is a significant advantage over conventional textile finishing layers.

According to the second embodiment of the present invention, the structure shown in FIG. 3 has an air permeability coefficient of 25 × 10 ^-12 [cc · cm].
/ Cm ² · sec · cmHg] having an air permeation preventing layer 3 substantially covering the tire inner surface, which is made of a film of a thermoplastic resin or a thermoplastic elastomer composition containing a blend of a thermoplastic resin and an elastomer. And so that the air permeation prevention layer 3 is sandwiched between the tire carcass layer 2 and
A pneumatic tire provided with a textile finishing layer having a cover factor A defined by the following formula that is greater than 0 and equal to or less than 1000 is provided. A = (average denier of code contained in the textile finishing layer) ^{0. 5} × (average code number of implanted per 50mm wide textile finishing layer) finishing layer the value of the cover factor A is folded to exceed 1000 The force for returning to the original shape of 5 becomes large, and as a result, the film 3 is peeled off as described above, which is not preferable.

Further, according to a third aspect of the present invention, for example, as shown in FIG. 4, a structure in which a finishing layer 5 formed by rubberizing a rubber or a textile is disposed inside a bead portion 1 of an air permeation preventing layer 3. By doing so, the finishing layer 5 comes into direct contact with the tire carcass layer 2, so that the finishing layer 5 is not peeled off from the carcass layer 2 under the influence of the air permeation prevention layer 3. Further, gum finishing or textile finishing having a cover factor A of 0 to 1000 as shown in FIG. 5 may be added to the outermost part of the bead portion. Also in this case, the air permeation preventing layer 3 may be wound up by the bead core 1 as shown in FIG. As a cord used for the textile finishing layer, organic fibers such as nylon, vinylon, and polyester can be used, but a nylon cord is preferably used. This is the same in the case of the second embodiment.

Further, as shown in FIG. 6, for example, according to the third aspect of the present invention, the height measured in the tire radial direction from the bead toe portion 8 at the end of the air permeation preventing layer 3 with respect to the tire sectional height SH. ht ratio is 0 to 30%, preferably 0 to 2%.
By setting the content to 5%, it is possible to obtain a light-weight tire without causing a manufacturing failure and without impairing the purpose of protecting the bead portion, and various cut shapes of the film end portion can be obtained. can do. If the ratio of ht / SH exceeds 30%, air leakage deteriorates, which is not preferable for practical use. In this embodiment, the lower end position of the air permeation preventing layer 3 is such that ht is 2 mm or more,
It is preferably at least mm and lower than the upper end of the bead filler. Furthermore, when ht is 5 mm or more, the height of the bead filler is 1 /
It is preferably 2 or less.

FIG. 7 shows that the air permeation preventing layer 3 has a bead toe portion 8.
If it is wrapped more outward, this will damage the air permeation prevention layer when assembling the rim, the coefficient of friction between the film and the rim is smaller than that between the rubber and the rim, and it is slippery, so the rim slippage Is not practical.

Further, as noted above, in this aspect of the invention,
The cutting shape 9 at the end of the air permeation preventing layer 3 is changed from, for example, a conventional general linear shape (FIG. 8A) to a saw blade shape 9 ′ shown in FIG. Any shape such as a corrugated shape 9 ″ as shown in c) and an uneven shape 9 ″ ″ as shown in FIG. 8 (d) can be used to improve the tire appearance, and to improve the circumferential direction when beading. Wrinkles that occur on the surface can be suppressed.

[0013] Further, as shown in FIG.
Is wound under the bead core, mechanical peeling is prevented, so that a textile finishing layer can be used. In this case, as shown in FIG.
A structure that stops under the bead core 1 in the middle may be used.

Further, as shown in FIG. 10, the air permeation preventing layer 3 may be wound up by a bead core 1. However, in this case, if the wire is excessively wound, burrs may occur at the time of molding. Therefore, the winding height h is up to about 25 mm from the bead heel 7. In this case, the finishing layer must be a gum finishing layer.

According to another aspect of the present invention, the air permeation prevention layer and the finishing layer have a structure in which there is a portion overlapping in the radial direction, and at least one of the air permeation layer and the adjacent layer is provided between the air permeation prevention layer and the finishing layer. By applying the adhesive to the portion, the adhesive strength of the applied portion is increased, so that not only the gum finishing layer but also the textile finishing layer can be used, and the structure thereof is arbitrary.

According to still another embodiment of the present invention, for example, as shown in FIG. 11, a structure in which the lower end of the film 3 does not overlap with the finishing layer 5 can be provided. In this case, if the height ht measured from the bead toe portion 8 at the lower end of the film 3 in the tire radial direction exceeds 30% with respect to the tire cross-section height SH, the air leakage resistance performance is insufficient. Must be 30% or less.

In these cases, there is no air permeation preventing layer having a relatively small adhesive force between the carcass and the finishing, and the peeling of the finishing is suppressed structurally, so that a cord more than the conventionally used finishing is driven. Finishing, for example, finishing in which the cover factor A is 1500 can also be used. Examples of the weaving method of the finishing cord of the textile of the present invention include plain weaving, entangled weaving, twill weaving, satin weaving, basket weaving and the like.

These tires, like conventional tires,
Although the air permeation prevention layer is arranged inside the carcass layer,
An air permeation prevention layer may be disposed outside the carcass layer (see FIGS. 12, 13, 14, and 15).

The film constituting the air permeation preventing layer of the pneumatic tire according to the present invention has an air permeability of 25 × 10
^-12 cc · cm / cm ² · sec · cmHg or less, preferably 5 × 1
^{0 -1 2 cc · cm / cm} 2 · sec · cmHg or less at Young's modulus 1
500 MPa, preferably 10 to 300 MPa, and the thickness of the film is preferably 0.0
The thickness is preferably 2 mm or more, and is preferably 1.1 mm or less from the viewpoint of weight reduction, and more preferably 0.05 to 0.2 mm.
Air permeability is 25 × 10 ^-12 cc · cm / cm ² · sec · cmHg
Exceeding this is not preferable in terms of reducing the weight of the pneumatic tire. On the other hand, if the Young's modulus is too low, wrinkles or the like occur during the molding of the tire, which lowers the molding processability.

The material constituting the film of the thermoplastic elastomer composition containing the thermoplastic resin or the blend of the thermoplastic resin and the elastomer used in the present invention may be any material having an air permeation preventing effect. Examples of such a thermoplastic resin include the following thermoplastic resins. Polyamide resin (for example, nylon 6 (N6), nylon 66 (N
66), nylon 46 (N46), nylon 11 (N1
1), nylon 12 (N12), nylon 610 (N6
10), nylon 612 (N612), nylon 6/6
6 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 / PP
S copolymer) and N-alkoxyalkylated products thereof, for example, methoxymethylated product of 6-nylon, 6-6
Methoxymethylated 10-nylon, methoxymethylated 612-nylon, polyester resin (for example, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyethylene isophthalate (PEI), PET / PEI copolymer, polyarylate (PAR), polybutylene naphthalate (PBN),
Liquid crystal polyester, polyoxyalkylenediimidic acid /
Aromatic polyesters such as polybutylate terephthalate copolymer), polynitrile resins (eg, polyacrylonitrile (PAN), polymethacrylonitrile, acrylonitrile / styrene copolymer (AS), methacrylonitrile / styrene copolymer, methacrylic Lonitrile / styrene / butadiene copolymer), polymethacrylate-based resin (eg, polymethyl methacrylate (PMMA), polyethyl methacrylate), polyvinyl-based resin (eg, vinyl acetate, polyvinyl alcohol (PVA), vinyl alcohol / ethylene copolymer) Polymer (EVOH), polyvinylidene chloride (PDVC), polyvinyl chloride (PVC), vinyl chloride / vinylidene chloride copolymer, vinylidene chloride /
Methyl acrylate copolymer, vinylidene chloride / acrylonitrile copolymer), cellulosic resin (eg, cellulose acetate, cellulose acetate butyrate), fluororesin (eg, polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), polychlorofluoro) Ethylene (PCT
FE), tetrafluoroethylene / ethylene copolymer),
An imide-based resin (for example, aromatic polyimide (PI)) can be given. Further, a thermoplastic elastomer composition containing a blend of the above thermoplastic resin and an elastomer, by mixing an elastomer with the above thermoplastic resin,
It is not limited to the types of materials and the mixing ratio as long as it can be configured and has an air permeation preventing action.

Examples of the elastomer which can be blended with the thermoplastic resin include the following. Diene rubbers and hydrogenated products thereof (for example, NR, IR, epoxidized natural rubber, SBR, BR
(High cis BR and low cis BR), NBR, hydrogenated NB
R, hydrogenated SBR), olefin rubbers (eg, 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 rubber (for example, bromide of Br-IIR, C1-IIR, isobutylene paramethylstyrene copolymer (Br-
IPMS), chloroprene rubber (CR), hydrin rubber (CHR), chlorosulfonated polyethylene (CS
M), chlorinated polyethylene (CM), maleic acid-modified chlorinated polyethylene (M-CM)), silicone rubber (for example, methyl vinyl silicone rubber, dimethyl silicone rubber,
Methylphenylvinyl silicone rubber), sulfur-containing rubber (for example, polysulfide rubber), fluorine rubber (for example, vinylidene fluoride rubber, fluorine-containing vinyl ether rubber, tetrafluoroethylene-propylene rubber,
Examples thereof include fluorine-containing silicon-based rubber and fluorine-containing phosphazene-based rubber), and thermoplastic elastomers (for example, styrene-based elastomer, olefin-based elastomer, ester-based elastomer, urethane-based elastomer, and polyamide-based elastomer).

In the method for producing a thermoplastic elastomer composition, a thermoplastic resin component and an elastomer component (unvulcanized product in the case of rubber) are melt-kneaded in advance with a twin-screw kneading extruder or the like.
By dispersing an elastomer component as a dispersed phase (domain) in a thermoplastic resin forming a continuous phase (matrix). When vulcanizing the elastomer component, a vulcanizing agent may be added under kneading to dynamically vulcanize the elastomer component. The various additives (excluding the vulcanizing agent) to the thermoplastic resin or the elastomer component may be added during the kneading, but it is preferable to mix them before kneading. The kneader used for kneading the thermoplastic resin and the elastomer component is not particularly limited, and a screw extruder, a kneader, a Banbury mixer, a twin-screw kneader or the like can be used. Above all, 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 kinds of kneaders may be used and the kneading may be performed sequentially. As the conditions for the melt-kneading, the temperature may be at least the temperature at which the thermoplastic resin melts. The shear rate during kneading is 1000-7500 Sec.
It is preferably ^-1 . The whole kneading time is 30 seconds to 1
When the vulcanizing agent is added for 0 minute, the vulcanizing time after the addition is preferably 15 seconds to 5 minutes.

When the compatibility between the specific thermoplastic resin and the elastomer component is different, it is preferable to use a suitable compatibilizing material as the third component to compatibilize the two.
By mixing the compatibilizer into the system, the interfacial tension between the thermoplastic resin and the elastomer component is reduced, and as a result, the rubber particles forming the dispersion layer become finer, so that the properties of both components are more improved. It will be effectively expressed. Such a compatibilizer is generally a copolymer having a structure of both or one of a thermoplastic resin and an elastomer component, or an epoxy group, a carbonyl group, a halogen group, an amino group capable of reacting with the thermoplastic resin or the elastomer component. It can be a copolymer having a group, an oxazoline group, a hydroxyl group and the like. These may be selected according to the type of thermoplastic resin and elastomer component to be mixed,
Commonly used ones are styrene / ethylene / butylene block copolymer (SEBS) and its maleic acid-modified product, EPDM, EPDM / styrene or EPDM / acrylonitrile graft copolymer and its maleic acid-modified product, styrene / maleic acid Copolymers, reactive phenoxines and the like can be mentioned. The amount of the compatibilizer is not particularly limited, but is preferably 0.5 to 10 parts by weight with respect to 100 parts by weight of the polymer component (total of the thermoplastic resin and the elastomer component).

When blending the thermoplastic resin and the elastomer, the composition ratio of the specific thermoplastic resin component (A) and the elastomer component (B) is not particularly limited, and may be appropriately determined according to the Young's modulus and the thickness of the molded article. A preferred range is 90/10 to 30/70 by weight. In the polymer composition according to the present invention, in addition to the essential polymer component, other polymers such as the above-described compatibilizer polymer may be mixed as long as the necessary properties of the polymer composition for a tire of the present invention are not impaired. it can. The purpose of mixing other polymers is to improve the compatibility between the thermoplastic resin and the elastomer component, to improve the moldability of the molded material, to improve the heat resistance, to reduce the cost, etc. ,
As a material used for this, for example, polyethylene (PE), polypropylene (PP), polystyrene (P
S), ABS, SBS, polycarbonate (PC), and the like. The polymer 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, which are generally added to the polymer compound. Processing aids, pigments, dyes, antioxidants and the like can be arbitrarily compounded as long as the requirements for the air permeability and Young's modulus are not impaired. Further, the elastomer component can dynamically vulcanize the elastomer component at the time of mixing with the thermoplastic resin. The vulcanizing agent, vulcanization aid, vulcanization conditions (temperature, time) and the like for dynamically vulcanizing the elastomer component may be appropriately determined depending on the composition of the elastomer component to be added, and are particularly limited. Not something.

As the vulcanizing agent, a general rubber vulcanizing agent (crosslinking agent) can be used. Specifically, examples of the ionic vulcanizing agent include powdered sulfur, precipitated sulfur, highly dispersible sulfur, surface-treated sulfur, insoluble sulfur, dimorpholine disulfide, and alkylphenol disulfide. About 4 phr [parts by weight per 100 parts by weight of the rubber component (polymer)] can be used. As the organic peroxide vulcanizing agent, benzoyl peroxide, t-butyl hydroperoxide, 2,4-bichlorobenzoyl peroxide, 2,2
5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethylhexane-2,5-di (peroxylbenzoate) and the like are exemplified.
About 0 phr can be used. Further, examples of the phenol resin-based vulcanizing agent include brominated alkylphenol resins and mixed cross-linking systems containing a halogen donor such as tin chloride and chloroprene and an alkylphenol resin. Can be.

Others include zinc white (about 5 phr), magnesium oxide (about 4 phr), litharge (10 to 20 phr).
phr), p-quinonedioxime, p-dibenzoylquinonedioxime, tetrachloro-p-benzoquinone,
Poly-p-dinitrosobenzene (about 2 to 10 phr),
Methylene dianiline (about 0.2 to 10 phr) can be exemplified. If necessary, a vulcanization accelerator may be added. As vulcanization accelerators, aldehyde / ammonia,
General vulcanization accelerators such as guanidine, thiazole, sulfenamide, thiuram, dithioate and thiourea can be used, for example, in an amount of about 0.5 to 2 phr.

Specifically, hexamethylenetetramine or the like is used as the aldehyde / ammonia-based vulcanization accelerator, diphenylguanidine is used as the guanidine-based vulcanization accelerator, and dibenzothiazyl is used as the thiazole-based vulcanization accelerator. Examples of sulfenamide-based vulcanization accelerators such as disulfide (DM), 2-mercaptobenzothiazole and its Zn salt and cyclohexylamine salt include cyclohexylbenzothiazylsulfenamide (CBS) and N-oxydiethylenebenzothiazyl. Examples of thiuram-based vulcanization accelerators such as -2-sulfenamide, Nt-butyl-2-benzothiazolesulfenamide, and 2- (thymolpolynyldithio) benzothiazole include tetramethylthiuram disulfide (TMTD). ), Tetraethylthiuram disulfi , Tetramethylthiuram monosulfide (TMTM), dipentamethylenethiuram tetrasulfide and the like, as the dithio acid salt-based vulcanization accelerator,
Zn-dimethyldithiocarbamate, Zn-diethyldithiocarbamate, Zn-di-n-butyldithiocarbamate, Zn-ethylphenyldithiocarbamate, T
e-diethyldithiocarbamate, Cu-dimethyldithiocarbamate, Fe-dimethyldithiocarbamate,
Examples of thiourea-based vulcanization accelerators such as pipecoline pipecolyl dithiocarbamate include ethylene thiourea and diethyl thiourea. As a vulcanization accelerating auxiliary, a general rubber auxiliary may be used in combination, for example, zinc white (about 5 phr), stearic acid, oleic acid and Zn salt thereof (about 2 to 4 phr). Etc. can be used.

The film thus obtained has a structure in which an elastomer is dispersed as a discontinuous phase in a matrix of a thermoplastic resin. By adopting such a structure, it is possible to impart sufficient flexibility to the film and sufficient low air permeability due to the effect of the resin layer of the continuous phase, and to mold the thermoplastic resin regardless of the amount of the elastomer. Sex can be obtained.

In another embodiment of the present invention, a pressure-sensitive adhesive is applied to at least one part between the air permeation preventing layer and the adjacent layer to increase the adhesive strength between the layers and to reduce the air in the bead portion. Regardless of the structure or material of the transmission preventing layer and the finishing layer, it is possible to prevent manufacturing defects such as floating. The adhesive is not particularly limited, and any conventionally used adhesive can be used with a thickness of, for example, about 1 μm to 100 μm. This adhesive is easy to work because it has tackiness at the time of tire molding, and is crosslinked by heat at the time of tire vulcanization, and has an action of strongly bonding the air permeation prevention layer and the tire member. . The adhesive agent used in the present invention is a polymer component having a critical surface tension difference (Δγc) of 6 mN / m or less, preferably 3 mN / m or less, respectively, between the surface polymer component of the air permeation preventing layer and the rubber component of the tire member. Adhesive composition containing is desirable, the polymer serving as the main component of the adhesive, general unvulcanized rubber, acrylate copolymer, polyether and polyester polyol, styrene copolymer,
Modified styrene copolymers, polyolefins, etc., specifically polymerize natural rubber, unvulcanized rubber such as SBR, BR, IR, EPDM, and monomers such as butyl acrylate, 2-ethylhexyl acrylate, and ethyl acrylate. Polymers obtained by the above, copolymers thereof and ethylene, polypropylene glycol, polyethylene glycol, polytetramethylene glycol, adipic acid and glycol, ethylene adipate is a condensate of triol,
Butylene adipate, diethylene adipate, styrene ethylene butylene copolymer, styrene ethylene propylene copolymer and their epoxy group, carboxyl group,
Modified products having an amino group, a maleic anhydride group, or the like are given.

The crosslinking agent can be freely selected from vulcanizing agents for general rubbers, isocyanate-based crosslinking agents, amine-based crosslinking agents and the like according to the type of polymer. Specifically, the sulfur type includes powdered sulfur, precipitated sulfur, highly dispersible sulfur, surface-treated sulfur, insoluble sulfur, and dimorpholine.
Disulfide, alkyl-phenol-disulfide, etc., for example, about 1 to 4 phr (parts by weight per 100 parts by weight of rubber, hereinafter the same), as peroxides, for example, benzoyl peroxide, t-butyl hydroperoxide Oxide, 2,4-dichlorodibenzoyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethylhexane-
2,5-di (peroxyl benzoate) is, for example, 1 to
About 15 phr, others are zinc white (about 5 phr),
Magnesium oxide (about 4 phr), litharge (10-2
0 phr), p-quinone dioxime, p-dibenzoyl quinone dioxime, tetrachloro-p-benzoquinone, poly-p-dinitrosobenzene (about 2 to 10 phr) and the like.

As the isocyanate component, any one which can be cross-linked by heat during tire vulcanization can be used. Specifically, TDI, MDI, crude MDI,
NDI, HDI, IPDI and the like can be mentioned. The compounding ratio of the polyester polyol and the isocyanate is an index (-NCO / -OH × 100 =) 50.
The range of ~ 200 is preferred. Outside this range, the adhesiveness is poor and the adhesiveness is reduced, and the tire member and the thermoplastic film are not bonded.

As the vulcanization accelerator, a general rubber vulcanization accelerator can be used, for example, 0.5 to 2 phr. Specifically, aldehyde human ammonia system (for example, hexamethylenetetramine), guanidine system (for example, diphenyl guanidine), thiazole system (for example, 2-mercaptobenzothiazole and its Zn salt, cyclohexylamine salt, dibenzothiazyl disulfide), Sulfenamide-based (for example, cyclohexyl benzothiazyl sulfenamide, N-oxydiethylene benzothiazyl-2-sulfenamide, Nt-butyl-
2-benzothiazolesulfenamide, 2- (thymolpolinyldithio) benzothiazole), thiurams (eg, tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetramethylthiuram monosulfide, dipentamethylenethiuram.
Tetrasulfide), dithioate salts (for example, Zn-dimethyl dithiocarbamate, Zn-diethyl dithiocarbamate, Zn-di-n-butyl dithiocarbamate, Zn-ethylphenyl dithiocarbamate,
Te-diethyl dithiocarbamate, Cu-dimethyl dithiocarbamate, Fe-dimethyl dithiocarbamate, pipecoline pipecolyl dithiocarbamate), thiourea (eg, ethylene thiourea, diethyl thiourea) and the like can be mentioned. When the tackiness of the adhesive is insufficient, a tackifier can be added.

As the tackifier, any one used for general pressure-sensitive adhesives and adhesives, for example, 10 to 100 ph
r can be used. Specifically, for example, (a) rosin resin (eg, rosin such as gum rosin, tall oil rosin, wood rosin; basic rosin such as hydrogenated rosin, disproportionated rosin, polymerized rosin, maleated rosin;) rosin glycerin ester (ester) Gums), rosin esters such as hydrogenated rosin / glycerin esters; and (b) resins having polar groups such as terpene phenol resins, and resins not having polar groups such as α-pinene-based, β-pinene-based, and dipentene (limonene) -based Natural products such as aromatic hydrocarbon-modified terpene resins and derivatives thereof and, for example, (c) petroleum resins such as aliphatic, alicyclic and aromatic; and (d) cumarone-indene resins;
(E) Polymer resins such as styrene resins such as styrene resins and substituted styrene resins; phenol resins such as (f) alkylphenol resins and rosin-modified phenol resins; and (g) condensation resins such as xylene resins. it can.

When it is necessary to increase the adhesive strength as other components, an additive which reacts with the film material or the rubber material corresponding to the film material, or the film material or the film material is added to the adhesive composition. Some additives having a critical surface tension closer to the rubber material relative to the material can also be incorporated. When a nylon-based resin is used as the thermoplastic film material, resorcinol-formalin resin, glycoluril resin or the like is used as the additive, and when a polyester-based resin is used, isocyanate or the like is preferable. The amount of the additive is preferably 0.5 to 10 parts by weight based on 100 parts by weight of the polymer. Further, when coloring is desired, carbon or a coloring agent can be blended.

The adhesive of the present invention is dissolved in a solvent or the like in advance and applied to the adhesive surface with a brush, a spray, a roller, or the like, or formed into a thermoplastic film by a dip roll coater, a kiss roll coater, a knife coater, or the like. As a method to keep it attached, or a method without using a solvent,
A cohesive layer can be easily formed by coextrusion or lamination at the time of preparing a thermoplastic film and preparing a two-layer film.

As a solvent for forming a solvent-based adhesive, a general solvent can be used, and specific examples thereof include aromatic solvents (benzene, toluene, xylene, etc.) and aromatic solvents.
Aliphatic mixture (MSP, SBP, Swazole 100, Swazole 200, Benzol Arrow 40.
H. A. W. S. , White spirit, etc.), aliphatic esters (rubber volatile oil, ethyl acetate, etc.), alcohols and ketones (methanol, acetone, methyl ethyl ketone, methyl isobutyl ketone) and the like. The choice can be chosen according to the evaporation rate. These solvents may be used as a mixture of two or more kinds. The amount of solvent added
What is necessary is just to determine according to the viscosity as an adhesive. The viscosity is 10 cps to 1000 cps, preferably 50 to 500 cps
When the viscosity is less than 10 cps, the coating amount is small and the adhesive strength is insufficient. On the other hand, when the viscosity exceeds 1000 cps, it becomes difficult to handle at the time of coating, which is not preferable.

[0037]

EXAMPLES The present invention will be further described below with reference to Examples and Comparative Examples, but it goes without saying that the scope of the present invention is not limited to these Examples. Examples 1 to 18 and Comparative Examples 1 to 9 Normal butyl rubber, material A for air permeation prevention layer shown below
A steel radial tire (size: 165SR13) having an air permeation preventing layer having the configuration shown in Tables I to VI was produced using the polymer films of Nos. To D and the adhesive agent.
The following tests were performed on these tires.

Material A In advance, 100 parts of SBR, carbon black HAF60
Parts, 1 part of stearic acid, 10 parts of petroleum hydrocarbon resin (Escolets 1102, Esso), and 10 parts by weight of paraffin oil (Machine oil 22, Showa Shell) were kneaded with a rubber banbury to prepare a master batch. . next,
Nylon 6 (Amilan CM1041,
Toray) 50 parts and 90.5 parts of the above master batch were kneaded to disperse the rubber component in the resin component.
1.5 parts, DM (Noxeller DM, Ouchi Shinko Chemical) 0.
5 parts and 0.3 parts of sulfur were added, and the mixture was dynamically vulcanized and pelletized. This is extruded with a T-die and has a thickness of 0.1 mm.
Was produced. The air permeability coefficient of the film is
At 4.33 × 10 ⁻¹² cc · cm / cm ² · sec · cmHg, the Young's modulus was 91 MPa.

[0039]Material B Nylon 6/66 copolymer (Amilan CM6021, East
B) was formed into a film in a T-die extruder. Film is thick
0.05mm, air permeability 0.84 × 10^-12cc
・ Cm / cm ^Two・ Sec ・ cmHg and Young's modulus is 244MPa
Was.

Material C nylon 6 (Amilan CM1041, Toray) 25.2
Parts, MXD6 nylon (Renny 6001, Mitsubishi Gas Chemical) 37.8 parts, nylon 6/66/610 (Amilan CM4001, Toray) 10.2 parts, Br- (polyisobutylene-P-methylstyrene) (EXXPRO89-
4, Exxon Chemical) 27 parts were kneaded with a biaxial kneader to disperse the rubber in the resin component, and then 0.12 parts of ZnO, zinc stearate and stearic acid were added, respectively.
0.6 parts and 0.3 parts were added, dynamic vulcanization was performed, and pelletized. This is extruded with a T-die and has a thickness of 0.05
mm film. The air permeability coefficient of the film was 0.63 × 10 ⁻¹² cc · cm / cm ² · sec · cmHg, and the Young's modulus was 317 MPa.

Material D Nylon 6.66 copolymer (Toray Amiran CM604)
1) 13 parts, nylon 11 (Atochem Rilsan BM)
NO) and 50 parts of Br- (polyisobutylene-P-methylstyrene) (EXPRO89-4, Exxon Chemical) with a twin-screw kneader to disperse the rubber in the resin component. 0.3 parts, 1.2 parts, and 0.6 parts of zinc stearate and stearic acid were added, respectively, and dynamic vulcanization was performed to form pellets. This was extruded with a T-die and processed into a film having a thickness of 0.10 mm. The air permeability coefficient of the film is 8.50 × 10 ^-12 cc
The Young's modulus was 60 MPa at cm / cm ² · sec · cmHg.

Butyl rubber: air permeability coefficient 55 × 10 ^-12
General butyl rubber with cc · cm / cm ² · sec · cmHg and Young's modulus 15MPa. Mixing ratio of the adhesive used in Table V EEA ethylene ethyl acrylate copolymer 100 DPDJ-6169 (Nihon Unicar) Quinton A-100 (Zeon Japan) 60 dicumyl peroxide 1 FEF-black 10 toluene 400 MEK 100 n- Hexane 100 With the above composition, EEA and Quinton A-10 in a kneader
0, and the composition of FEF black was mixed and stirred in a mixed solvent of toluene or less with a homogenizer (rotation speed: 8000 rpm) to obtain an adhesive. Finally, dicumyl peroxide was added and stirred.

[0043]

[Table 1]

[0044]

[Table 2]

[0045]

[Table 3]

[0046]

[Table 4]

[0047]

[Table 5]

[0048]

[Table 6]

[0049]

[Table 7]

[0050]

[Table 8]

The test methods used for evaluating the examples and comparative examples are as follows. Air leak test method (pressure drop rate) Assemble a tire into a rim 13 × 41 / 2J and set an initial pressure of 20
0kPa, room temperature 21 ℃, left for 3 months under no load condition,
The tire pressure is measured every four days. Measurement pressure Pt, initial pressure
As Po and the number of elapsed days t, an α value was obtained by regression on a function of the formula: Pt / Po = exp (−αt). Using the obtained α value, t = 30 (days) is substituted, and the pressure drop rate β per month β [% / month] is obtained from the formula β = [1-exp (−αt)] × 100 and displayed. did.

Judgment of manufacturing failure (or failure) The green tire was allowed to stand at room temperature for 24 hours after molding, and the state of the air permeation preventing layer and the finishing at the bead portion was confirmed.

[Evaluation Method for Damage of Lower Edge of Air Permeation Preventing Layer at Assembling of Rim] The tire is repeatedly assembled and removed 10 times by a rim assembling apparatus, and the end of the air permeation preventing layer is observed for cracks or peeling. did. If there were no cracks even after repeating 10 times, "No" means that there was no peeling or cracking after 3 times, but if there was some peeling or cracking after 7 more times, it was "fine" and 3 times. At that point, those that had already cracked or peeled off were marked as "Yes".

[Rim slip evaluation method] A tire was assembled on a standard rim specified by the JATMA standard, air was sealed at a pressure of 200 kPa, and the tire and the rim were displaced in the circumferential direction between the evaluation tire and the rim assembled with the rim. Draw a reference line as you can sometimes see. The tire is mounted on a small passenger car with a displacement of 1500 cc, and rapid braking is performed while driving on a dry road surface at a speed of 50 km / h. After repeating this rapid braking three times in a row, it was observed whether or not the previous reference line had shifted.

[Existence of Peeling at End of Air Permeation Prevention Layer After Running] 140 kP with standard rim specified by JATMA standard
a. At a pressure of a, air is sealed, and on a drum having an outer diameter of 1700 mm, a load of 300 kN and a speed of 80 km /
After traveling for a distance of 10,000 km at h, the end of the air permeation preventing layer after traveling was observed for peeling. At this stage, the case where there was peeling was determined as “present”. Further, after traveling 10,000 km under the above conditions, the presence or absence of peeling of the air permeation preventing layer after traveling again was observed. If the peeling was 2 mm or less, it was judged as “fine”. Was determined.

Measurement of Finishing Cover Factor A
Determining method (i) A finishing layer is collected from the inner surface of the bead core of the tire, immersed in toluene to swell the rubber, and then the rubber is removed. The cord was collected from the residue from which the rubber had been removed, the length and mass were measured, converted into denier numbers, and the denier numbers obtained for each of the length and width were averaged. (Ii) For each cord direction, the number of cords to be driven in a range of 50 mm in width in a direction perpendicular to the cord direction is measured, and the values are averaged. (Iii) The cover factor A is calculated by the following equation. A = (Average number of deniers of cords included in textile finishing layer) ^0.5 × (Average number of cords per 50 mm width of textile finishing layer)

[0057]

As compared with the conventional air permeation preventing layer using butyl rubber, the film is made thinner and lighter by using a film that does not allow air to pass through, while the tackiness of the conventional film and the rigidity of the finishing layer are reduced. A pneumatic tire that is reduced in weight can be obtained without causing a manufacturing failure due to a manufacturing failure occurring in the bead portion due to the structure and material of the air permeation prevention layer and the finishing layer.

[Brief description of the drawings]

FIG. 1 is a schematic half sectional view of an example of a pneumatic tire in a meridian direction.

FIG. 2 shows an arrangement of a conventional finishing layer for protecting a bead portion of a conventional pneumatic tire and its problems.
(A), (b) and (c) are shown.

FIG. 3 is a view showing a first embodiment of the pneumatic tire according to the present invention, wherein cover factor A is used as a finishing layer.
Is greater than 0 and 1000 or less, or a gum finishing layer is used.

FIG. 4 is a drawing showing another embodiment of the pneumatic tire of the present invention, in which a finishing layer is sandwiched between an air permeation preventing layer and a carcass layer.

FIG. 5 is a view showing another embodiment of the pneumatic tire of the present invention. In this embodiment, the pneumatic tire has a structure in which an inner finishing layer and an outer gum finishing layer are provided.

FIG. 6 is a view showing another embodiment of the pneumatic tire of the present invention, in which the end of the air permeation prevention layer is located above the bead toe.

FIG. 7 is a drawing showing a pneumatic tire of a comparative example, in which an air permeation prevention layer is wound outside a bead toe portion.

FIG. 8 is a view showing a cut shape of an end portion in the tire width direction of the air permeation preventing layer of the present invention, showing variations of (a), (b), (c) and (d).

FIG. 9 is a view showing another embodiment of the pneumatic tire of the present invention. In this embodiment, the radial edge of the air permeation prevention layer 3 is arranged on the bead heel portion 7 and the bead core portion 1 is provided.
Is arranged radially inside.

FIG. 10 is a view showing another embodiment of the pneumatic tire of the present invention. In this embodiment, the air permeation preventing layer 3 is wound up by a bead core 1 and the height of the air permeation preventing layer 3 from the bead heel portion 7 is set to h. .

FIG. 11 is a view showing another embodiment of the pneumatic tire of the present invention. In this embodiment, the lower end of the air permeation preventing layer 3 is stopped at a position of height ht from the bead toe portion 8 and does not overlap with the finishing layer. I do.

FIG. 12 is a drawing showing another embodiment of the pneumatic tire of the present invention, in which an air permeation prevention layer is disposed inside a carcass layer.

FIG. 13 is a view showing another embodiment of the pneumatic tire of the present invention, in which an air permeation prevention layer is disposed inside a carcass layer.

FIG. 14 is a drawing showing another embodiment of the pneumatic tire of the present invention, in which an air permeation preventing layer is disposed inside a carcass layer.

FIG. 15 is a view showing another embodiment of the pneumatic tire of the present invention, in which an air permeation prevention layer is disposed inside a carcass layer.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Bead core 2 ... Carcass layer 3 ... Air permeation prevention layer 4 ... Side wall 5 ... Finishing layer 6 ... Textile finishing layer or gum finishing layer whose cover factor A is more than 0 and 1000 or less 7 ... Bead heel part 8 ... Bead toe part 9 , 9 ', 9 ", 9"' ... shape of the end in the tire width direction of the air permeation prevention layer

Continuation of the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location C08L 21/00 C08L 21/00

Claims (7)

[Claims] An air permeability coefficient of 25 × 10 ⁻¹² [cc · cm /
cm ² · sec · cmHg] or less, having an air permeation prevention layer substantially covering the tire inner surface, comprising a film of a thermoplastic resin or a thermoplastic elastomer composition containing a blend of a thermoplastic resin and an elastomer. A pneumatic tire provided with a rubber finishing layer such that an air permeation prevention layer is sandwiched between the tire carcass layer. 2. An air permeability coefficient of 25 × 10 ^-12 [cc · cm]
/ Cm ² · sec · cmHg] or less, having an air permeation prevention layer substantially covering the tire inner surface, comprising a film of a thermoplastic resin or a thermoplastic elastomer composition containing a blend of a thermoplastic resin and an elastomer. The cover factor A defined by the following equation is larger than 0 and 1000 so that the air permeation prevention layer is sandwiched between the tire carcass layer and the tire carcass layer.
A pneumatic tire provided with the following textile finishing layer. A = (average denier of cord embedded in the textile finishing layer) ^{0. 5} × (average code number of implanted per 50mm wide textile finishing layer) 3. The air permeability coefficient is 25 × 10 ⁻¹² [cc · cm /
cm ² · sec · cmHg] or less, comprising a film of a thermoplastic resin or a thermoplastic elastomer composition containing a blend of a thermoplastic resin and an elastomer, having an air permeation prevention layer substantially covering the inner surface of the tire, and a finishing layer. Is sandwiched between a tire carcass layer and an air permeation prevention layer. 4. The pneumatic tire according to claim 3, wherein the ratio of the height ht measured in the tire radial direction from the bead toe portion at the end of the air permeation preventing layer to the tire cross-section height SH is 0% to 30%. . 5. An air permeability coefficient of 25 × 10 ⁻¹² [cc · cm /
cm ² · sec · cmHg] or less, comprising a film of a thermoplastic resin or a thermoplastic elastomer composition containing a blend of a thermoplastic resin and an elastomer. Air having a structure in which the radial end of the prevention layer is sandwiched between the finishing layer and the carcass layer, and the radial end of the air permeation prevention layer is located inside the tire core in the tire radial direction. Containing tires. 6. An air permeability coefficient of 25 × 10 ⁻¹² [cc · cm /
cm ² · sec · cmHg] or less, comprising a film of a thermoplastic resin or a thermoplastic elastomer composition containing a blend of a thermoplastic resin and an elastomer. A pneumatic tire having a structure in which a permeation preventing layer and a finishing layer overlap in a radial direction, and wherein at least one part between an air permeable layer and an adjacent layer is coated with an adhesive. 7. An air permeability coefficient of 25 × 10 ⁻¹² [cc · cm /
cm ² · sec · cmHg] or less, comprising a film of a thermoplastic resin or a thermoplastic elastomer composition containing a blend of a thermoplastic resin and an elastomer. A pneumatic tire having a structure in which the prevention layer and the finishing layer do not directly overlap each other, and having a ratio of a height ht measured in a tire radial direction from a bead toe portion at an end of the air permeation prevention layer to a tire sectional height SH of 30% or less.