JP2001239805A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pneumatic tire using a polymer composition as an air permeation preventing layer excellent in a balance between air permeation resistance and flexibility, excellent in adhesion to rubber, and capable of reducing the weight of the tire. SOLUTION: This pneumatic tire using the tire polymer composition as the air permeation preventing layer having an air permeability coefficient of 25×10-12 cc.cm/cm2.sec.cmHg or below and a Young's modulus of 1 to 500 MPa comprises 10 wt.% thermoplastic resin (A) having an air permeability coefficient of 25×10-12 cc.cm/cm2.sec.cmHg or below and a Young's modulus of above 500 MPa, 10 wt.% or more of elastomer (B) having an air permeability coefficient of above 25×10-12 cc.cm/cm2.sec.cmHg and a Young's modulus of 500 MPa or below, and 3 to 70 wt.% another thermoplastic resin (C) based on components A, B, and C, provided that the entire amount of components A and B being 30 wt.% or above. The resin C has a difference between the critical surface tension of this component used as a tire and that of the mating rubber layer of 3 mN/m or below.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an excellent balance between air permeation resistance and flexibility, and excellent adhesion to rubber.
A polymer composition for a tire that can reduce the thickness of the air permeation prevention layer such as the inner liner layer and reduce the weight of the tire without impairing the air pressure retention in the pneumatic tire is used for the air permeation prevention layer. Related pneumatic tires.

[0002]

2. Description of the Related Art Reduction of the fuel consumption rate is one of the major technical problems in automobiles, and as a measure against this, there is an increasing demand for lighter pneumatic tires.

[0003] On the inner surface of a pneumatic tire, an inner liner layer made of a rubber having a low gas permeability such as butyl rubber is provided to keep the tire air pressure constant. However, halogenated butyl rubber has a large hysteresis loss, so after vulcanization of the tire,
When the inner rubber of the carcass layer and the inner liner layer are corrugated in the gap between the carcass cords, the inner liner rubber layer is deformed together with the deformation of the carcass layer, so that the rolling resistance increases. Therefore, in general, the inner liner layer (halogenated butyl rubber) and the inner surface rubber of the carcass layer are joined to each other via a rubber sheet called a tie rubber having a small hysteresis loss. Accordingly, in addition to the thickness of the inner liner layer of the halogenated butyl rubber, the thickness of the tie rubber is added, resulting in a thickness exceeding 1 mm (1000 μm) as a whole, which results in an increase in the weight of the product tire. Had become one.

A technique has been proposed in which various materials are used in place of a low gas permeable rubber such as butyl rubber as an inner liner layer of a pneumatic tire. For example,
No. 3,176,61 discloses that an air permeability coefficient [cm ³ (standard condition) / cm · sec · mmHg] is 1 at 30 ° C. on the inner surface of a vulcanized tire.
It is disclosed that a solution or dispersion of a synthetic resin such as polyvinylidene chloride, a saturated polyester resin, or a polyamide resin of 0 × 10 ⁻¹³ or less and 50 × 10 ⁻¹³ or less at 70 ° C. is applied at 0.1 mm or less. I have.

However, the technology disclosed in this publication is
On the inner peripheral surface of the carcass of the vulcanized tire, or on the inner peripheral surface of the inner liner, a coating layer of a synthetic resin having a specific air permeability coefficient is provided to reduce the thickness of the synthetic resin coating layer to 0.1 mm or less. However, the pneumatic tire described in this publication has a problem in adhesion between the rubber and the synthetic resin film, and has a disadvantage that the inner liner layer is inferior in heat resistance and moisture resistance (or water resistance). .

JP-A-5-330307 discloses that the inner surface of a tire is subjected to a halogenation treatment (using a conventionally known chlorination treatment solution, a bromine solution and an iodine solution), and methoxymethylated nylon, Polymer film of polymerized nylon, blend of polyurethane and polyvinylidene chloride, blend of polyurethane and polyvinylidene fluoride (film thickness 1
0-200 [mu] m).

Further, Japanese Patent Application Laid-Open No. Hei 5-318618 discloses that
A pneumatic tire using a thin film of methoxymethylated nylon as an inner liner is disclosed. According to this technology, a solution or emulsion of methoxymethylated nylon is sprayed or applied to the inner surface of a green tire, and then the tire is vulcanized. Alternatively, a pneumatic tire is manufactured by spraying or applying a solution or emulsion of methoxymethylated nylon on the inner surface of the tire after vulcanization. However, the technique disclosed in this publication also has a disadvantage that it is difficult to maintain uniformity of the film thickness, in addition to the disadvantage that the thin film has poor water resistance.

[0008]

As described above, various materials for the inner liner layer of a pneumatic tire have been proposed in place of butyl rubber, but have not yet been put to practical use. Particularly, a material excellent in balance between air permeability and flexibility required for an inner liner layer of a pneumatic tire and further excellent in adhesion to rubber has not yet been developed. Therefore, an object of the present invention is to reduce the weight of a pneumatic tire without impairing the air pressure retention of the tire, and to achieve an excellent balance between air permeability and flexibility and adhesion to a rubber layer. An object of the present invention is to provide a pneumatic tire having an air permeation preventing layer formed using a polymer composition for a tire which is excellent as an air permeation preventing layer for a pneumatic tire.

[0009]

According to the present invention, (A)
Air permeability coefficient is 25 × 10 ^-12 cc · cm / cm ² · sec · cm
At least one thermoplastic resin having a Young's modulus of not more than 500 MPa and a Hg of not more than 10% by weight based on the weight of all polymer components and (B) an air permeability coefficient of 25 × 10 ^-12 cc · cm / cm ^2.
At least one elastomer component having a Young's modulus of 500 MPa or less and having a sec.
0% by weight or more, the total amount of component (A) and component (B) (A) + (B) is included in an amount of 30% by weight or more based on the weight of all polymer components, and (C) the above (A) The other thermoplastic resin having a critical surface tension difference of 3 mN / m or less with respect to the rubber layer when used as a tire for the thermoplastic resin of component (A), (B) and (C) The air permeability coefficient is 25 × 10 ⁻¹² cc · cm / cm ² , including 3 to 70% by weight.
The present invention provides a pneumatic tire using a layer of a polymer composition for tires having a Young's modulus of 1 to 500 MPa at sec.

The thermoplastic resin blended as the component (A) in the polymer composition according to the present invention has an air permeability coefficient of 2
5 × 10 ^-12 cc · cm / cm ² · sec · cmHg or less, preferably 0.1 × 10 ^-12 to 10 × 10 ^-12 cc · cm / cm ² · se
c ・ cmHg and Young's modulus is over 500MPa, preferably 500
Any thermoplastic resin having a pressure of up to 3000 MPa can be used, and the amount thereof is 10% by weight or more, preferably 20 to 85% by weight, based on the total weight of the polymer components including the resin and the rubber.

Examples of such a thermoplastic resin include the following thermoplastic resins and any of these or any resin mixture containing them. Further, a thermoplastic resin component to which an antioxidant or the like is added may be used.

A polyamide resin (for example, nylon 6 (N
6), nylon 66 (N66), nylon 46 (N4
6), nylon 11 (N11), nylon 12 (N1
2), nylon 610 (N610), nylon 612
(N612), nylon 6/66 copolymer (N6 / 6
6), nylon 6/66/610 copolymer (N6 / 66
/ 610), nylon MXD6, nylon 6T, nylon 6 / 6T copolymer, nylon 66 / PP copolymer, nylon 66 / PPS copolymer, polyester resin (for example, polybutylene terephthalate (PBT), polyethylene terephthalate (PET) ), Polyethylene isophthalate (PEI), PET / PEI copolymer, polyarylate (PAR), polybutylene naphthalate (PB)
N), liquid crystalline polyesters, aromatic polyesters such as polybutylene terephthalate / polytetramethylene glycol copolymer, polyoxyalkylenediimidodiacid / polybutylene terephthalate copolymer), polynitrile resins (eg, polyacrylonitrile (PAN), Methacrylonitrile, acrylonitrile / styrene copolymer (AS), methacrylonitrile / styrene copolymer,
Methacrylonitrile / styrene / butadiene copolymer), poly (meth) acrylate resins (eg, polymethyl methacrylate (PMMA), polyethyl methacrylate), polyvinyl resins (eg, vinyl acetate (EV)
A), polyvinyl alcohol (PVA), vinyl alcohol / ethylene copolymer (EVOH), polyvinylidene chloride (PDVC), polyvinyl chloride (PVC), vinyl chloride / vinylidene chloride copolymer, vinylidene chloride / methyl acrylate copolymer Coalescence), cellulosic resin (eg, cellulose acetate, cellulose acetate butyrate), fluororesin (eg, polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), polychlorofluoroethylene (P
CTFE), tetrafluoroethylene / ethylene copolymer (ETFE), imide resin (for example, aromatic polyimide (PI)) and the like.

As described above, these thermoplastic resins must have a specific air permeability coefficient, Young's modulus and blending amount. It has a flexibility of Young's modulus of 500 MPa or less and an air permeability coefficient of 25 × 10 ^-12 cc · cm / cm ² · sec · cmHg.
The following materials are not yet industrially developed and have an air permeability coefficient of 25 × 10 ⁻¹² cc · cm / cm ² · sec.
-If it exceeds cmHg, the air permeation resistance as a polymer composition for tires is lowered, and the tire does not function as an air permeation preventing layer. Further, when the blending amount of these thermoplastic resins is less than 10% by weight, the air permeation resistance similarly decreases, and it is not preferable to use as a tire air permeation preventing layer.

The elastomer component blended as the component (B) in the polymer composition according to the present invention has an air permeability coefficient of more than 25 × 10 ⁻¹² cc · cm / cm ² · sec · cmHg and a Young's modulus of 500 MPa. Any of the following elastomers or any blends thereof, or reinforcing agents, fillers, cross-linking agents, softening agents, anti-aging generally incorporated into elastomers for the purpose of improving the dispersibility or heat resistance of the elastomers, etc. The composition is an elastomer composition to which a required amount of compounding agents such as processing agents and processing aids are added. The compounding amount is 10% by weight or more based on the total weight of the polymer components including the resin and the elastomer component constituting the air permeation preventing layer, Preferably, the amount is 10 to 85% by weight, and the total amount of component (A) and component (B) (A) + (B) is 30% by weight or more based on the weight of all polymer components. .

The elastomer constituting such an elastomer component is not particularly limited as long as it has the above-mentioned air permeability coefficient and Young's modulus, and examples thereof include the following.

Diene rubber and its hydrogenated product (for example, N
R, IR, epoxidized natural rubber, SBR, BR (high cis BR and low cis BR), NBR, hydrogenated NBR, hydrogenated SBR), olefin rubber (eg, ethylene propylene rubber (EPDM, EPM), maleic acid modified) Ethylene propylene rubber (M-EPM), butyl rubber (II
R), isobutylene and aromatic vinyl or diene monomer copolymer, acrylic rubber (ACM), ionomer,
Halogen-containing rubber (for example, Br-IIR, Cl-IIR,
Brominated isobutylene paramethylstyrene copolymer (Br-IPMS), chloroprene rubber (CR), hydrin rubber (CHR, CHC), chlorosulfonated polyethylene (CSM), chlorinated polyethylene (CM), maleic acid-modified chlorinated polyethylene (M-CM)), silicone rubber (eg, methyl vinyl silicone rubber, dimethyl silicone rubber, methyl phenyl vinyl silicone rubber), sulfur-containing rubber (eg, polysulfide rubber), fluorine rubber (eg, vinylidene fluoride rubber, fluorine-containing vinyl ether rubber) , Tetrafluoroethylene-propylene rubber, fluorine-containing silicon rubber, fluorine-containing phosphazene rubber), thermoplastic elastomers (for example, styrene-based elastomer, olefin-based elastomer, polyester-based elastomer) Urethane elastomers, polyamide elastomers), and the like.

According to the present invention, a thermoplastic resin having a critical surface tension difference (Δγc) of 3 mN / m or less with respect to an opposite rubber layer when used as a tire is further used as a third component for imparting adhesion. It is blended in the composition in an amount of 3 to 70% by weight, preferably 3 to 50% by weight based on the total weight of the components (A), (B) and (C). If the amount is too small, adhesion to the opposing components will not be sufficient, and if it is too large, the air permeability coefficient will be too large or the elastic modulus will be too high, which is not practical.

Specific examples of the thermoplastic resin of the third component (C) according to the present invention include ultrahigh molecular weight polyethylene (UHMWP) having a molecular weight of 1,000,000 or more, preferably 3,000,000 or more.
E), ethylene-ethyl acrylate copolymer (EE
A), acrylate copolymers such as ethylene-acrylic acid copolymer (EAA) and ethylene-methyl acrylate resin (EMA) and maleic acid adducts thereof, polypropylene (PP), styrene / butadiene / styrene block copolymer (SBS), styrene-ethylene-butadiene-styrene block copolymer (SEBS), polyethylene (PE), ethylene-propylene copolymer (EP)
And the like.

Specific thermoplastic resin components (A) and (C)
The composition ratio of the total amount of the above and the elastomer component (B) may be appropriately determined depending on the balance between the thickness of the film, air permeability, and flexibility, but a preferred range is 10/90 to 90/1.
0, more preferably 20/80 to 85/15.

As described above, the polymer composition according to the present invention contains polymer components (A), (B) and (C) having specific air permeability and Young's modulus as essential components. FIG. 1 shows a graph as shown in FIG. 1. In FIG.
Is determined in the region Y, and the component (C) is determined on the basis of a critical surface tension difference of 3 mN / m or less with respect to the opposing rubber layer,
The resulting polymer composition corresponds to zone Z.

[0021] In the present invention, to determine the thermoplastic resin A ₁ to A _n belonging to the component (A), these average values Aav
(= ΣφiAi (i = 1 to n), where φi is weight% of Ai). The point Aav and the air permeability coefficient are 25 ×
^10-12 cc · cm / cm ² · sec · cmHg, Young's modulus 500MP
The point P of a is connected with a straight line, the lower side of the straight line obtained by extrapolating the straight line AavP, and the air permeability coefficient 25 × 10 ⁻¹² cc · cm /
In the region S _equal to or greater than cm ² · sec · cmHg, the (B) component belonging to the Y region, the average value Bav of B _{1 to} B _n (= ΣφiBi
(I = 1 to n), where φi is the weight% of Bi), and mixed with an appropriate blend.
By adding the component (C), it is possible to obtain a polymer composition which enters the target region Z.

Hereinafter, a pneumatic tire having an air permeation preventing layer manufactured using the polymer composition for a tire of the present invention will be described in more detail. The air permeation prevention layer of the pneumatic tire according to the present invention can be arranged at an arbitrary position inside the tire, that is, inside or outside the carcass layer, or at another position. In short, the object of the present invention is achieved by arranging the tire so as to prevent transmission and diffusion of air from the inside of the tire and maintain the air pressure inside the tire for a long period of time.

FIG. 2 is a meridional half cross-sectional view illustrating a typical example of the arrangement of the air permeation preventing layer of the pneumatic tire. In FIG. 2, a carcass layer 2 is mounted between a pair of left and right bead cores 1, 1, and an inner liner layer 3 is provided on the inner surface of the tire inside the carcass layer 2. In FIG. 2, reference numeral 4 denotes a sidewall.

In the present invention, the method for producing the polymer composition constituting the air permeation preventing layer is as follows: the thermoplastic resin component constituting the components (A) and (C) and the elastomer (unvulcanized product in the case of rubber) (B) is melt-kneaded with a twin-screw kneading extruder or the like, and an elastomer component is dispersed in a thermoplastic resin forming a continuous phase. When vulcanizing the elastomer component, a vulcanizing agent may be added under kneading to dynamically vulcanize the elastomer. The various additives (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 the kneading. The kneader used for kneading the thermoplastic resin and the elastomer is not particularly limited, and examples thereof include a screw extruder, a kneader, a Banbury mixer, and a twin-screw kneading extruder. Among them, it is preferable to use a twin-screw kneading extruder for kneading the resin component and the rubber component and for dynamically vulcanizing the rubber component. Further, two or more types of kneaders may be used to knead sequentially. As a condition for the melt-kneading, the temperature may be at least the temperature at which the thermoplastic resin melts. The shear rate during kneading is preferably 2500 to 7500 Sec ^-1 . The total kneading time is 30 seconds to 10 minutes, and when a vulcanizing agent is added, the vulcanizing time after addition is 15 seconds to 5 minutes.
Minutes is preferred. The polymer composition produced by the above method is then formed into a film by extrusion or calendering. The method of forming a film may be a method of forming a normal thermoplastic resin or thermoplastic elastomer into a film. The thin film thus obtained has a structure in which at least a part of the elastomer (B) is dispersed as a discontinuous phase in a matrix of the thermoplastic resins (A) and (C). By taking the dispersion structure in such a state, it is possible to impart a balance between flexibility and air permeability resistance, and it is possible to obtain effects such as improved heat deformation resistance, improved water resistance, and thermoplastic processing. For this reason, a film can be formed by a usual resin molding machine, that is, extrusion molding or calendar molding. The method of forming a film may be a method of forming a normal thermoplastic resin or thermoplastic elastomer into a film.

The method for producing a pneumatic tire having an air permeation preventing layer formed of a thin film of the polymer composition according to the present invention is applied to a case where the inner liner layer 3 is disposed inside the carcass layer 2 as shown in FIG. To explain one example,
The polymer composition of the present invention is extruded into a thin film having a predetermined width and thickness in advance, and the thin film is adhered to a cylinder on a tire building drum. Members used for normal tire production, such as a carcass layer, a belt layer, a tread layer, and the like made of unvulcanized rubber are sequentially laminated thereon, and the drum is pulled out to obtain a green tire. Next, by heating and vulcanizing the green tire according to a conventional method, a desired lightweight pneumatic tire can be manufactured. In addition, also when providing an air permeation prevention layer on the outer peripheral surface of a carcass layer, it can be performed according to this.

The material of the rubber layer to which the air permeation prevention layer according to the present invention is adhered is not particularly limited, and may be any rubber material conventionally used as a rubber material for tires. Examples of such rubbers include diene rubbers such as NR, IR, BR, SBR, halogenated butyl rubber, ethylene-propylene copolymer rubber,
A rubber composition can be obtained by adding a reinforcing agent such as carbon black, a softening agent such as process oil, and a compounding agent such as a plasticizer and a vulcanizing agent to a styrene-based elastomer or the like.

The air permeation prevention layer according to the present invention has an air permeability coefficient of 25 × 10 ⁻¹² cc · cm / cm ² · sec · cmHg or less.
It is preferably at most 5 × 10 ⁻¹² cc · cm / cm ² · sec · cmHg. Air permeability coefficient is 25 × 10 ^-12 cc · cm / cm ² ·
The thickness of the air permeation preventing layer can be reduced to 以下 or less of the thickness of the conventional air permeation preventing layer by setting it to sec · cmHg or less.

On the other hand, the Young's modulus is 1 to 500 MPa, preferably 10 to 300 MPa, and the thickness is 0.02 to 1.0 mm, preferably 0.05 to 0.5 mm. Young's modulus is 1MPa
If it is less than 500 MPa, it is not preferable because handling becomes difficult due to wrinkles and the like, and if it exceeds 500 MPa, it is not preferable because it cannot follow the deformation of the tire during running.

[0029]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but it goes without saying that the present invention is not limited to the following Examples. The evaluation methods used in the following examples are as follows.

Measurement Method of Air Permeability Coefficient of Film According to JIS K7126 "Test Method for Gas Permeability of Plastic Films and Sheets (Method A)". Test piece: The film sample prepared in each example was used. Test gas: air (N ₂ : O ₂ = 8: 2) Test temperature: 30 ° C

Measurement method of Young's modulus of film According to JIS K6251 “Tensile test method for vulcanized rubber”. Test piece: A film sample prepared by extrusion molding in each example was subjected to JIS in parallel with the direction of resin flow during extrusion.
I pierced it with No. 3 dumbbell. A tangent was drawn on a curve in the initial strain region of the obtained stress-strain curve, and the Young's modulus was determined from the slope of the tangent.

Evaluation Method of Fusion Adhesion to Rubber A 2 mm sheet of each resin was pressed with a hot press at a pressure of 3 MPa.
Press was performed in 20 minutes. The temperature at that time was the melting point of each resin + 20 ° C. The sheet is 1 inch wide, JI
When a peeling test was performed in accordance with SK6256, those that caused material destruction were evaluated as ○, and those that exhibited no peeling power were evaluated as x. The case where there was peeling force but interface peeling occurred was marked as “△”.
The rubber used at this time was SBR / NR = 50 parts: 50
In some systems, its γc was 30 mN / m.

Tire Air Leakage Performance Test Method 165SR13 Steel Radial Tire (Rim 13
× 41/2 -J), the pressure was measured every 4 days at an initial pressure of 200 kPa under no load conditions at room temperature of 21 ° C. for 3 months. As the measured pressure Pt, the initial pressure Po, and the number of elapsed days t, an α value is obtained by regressing on the function: Pt / Po = exp (−αt). Using the obtained α, t = 30
Is substituted into the following equation to obtain β = [1-exp (−αt)] × 100 β value. This β value is calculated as the pressure drop rate per month (% /
Month).

Tire running durability test method (inner liner
165SR13 steel radial tire (rim 13x )
41/2 -J), air pressure 140 kPa, load 5.5 kN
The tire inner surface is inspected after traveling 10,000 km at a speed of 80 km / h on a φ1707 mm drum at room temperature (38 ° C.) under the test conditions described above. The inner liner layer is visually inspected, and if the next failure is found, it is rejected. 1) Those with cracks and cracks 2) Those with peeling and rising

Examples 1 to 14 One or two of each of the various thermoplastic resin components (A) and (C) were added to the elastomer component (B) at various mixing ratios (parts by weight) shown in Tables I to XIV. In some cases, the vulcanizing agent, other components such as lubricants are kneaded with a twin-screw kneader and then continuously pelletized with a resin pelletizer. A film having a thickness of 0.1 mm was obtained. The air permeability coefficient and Young's modulus of the obtained film were measured, and the results are shown in Tables I to XIV, respectively.

[0036]

[Table 1]

[0037]

[Table 2]

[0038]

[Table 3]

[0039]

[Table 4]

[0040]

[Table 5]

[0041]

[Table 6]

[0042]

[Table 7]

[0043]

[Table 8]

[0044]

[Table 9]

[0045]

[Table 10]

[0046]

[Table 11]

[0047]

[Table 12]

[0048]

[Table 13]

[0049]

[Table 14]

Examples 15 and 16 and Comparative Examples 1 and 2 Various compounding agents were mixed with Br-IIR or Br-poly (isobutylene-p-methylstyrene) (Br-IPMS), and the mixture was mixed in a closed type Banbury mixer for rubber. Then, using a rubber roll, a rubber sheet having a thickness of 2.5 mm was formed to prepare master batches A and B. The sheet of the master batch A or B is pelletized by a rubber pelletizer, and the pellets are used to biaxially mix the components (A) and (C) and the master batch at various mixing ratios (parts by weight) shown in Table XV. The mixture was kneaded with a kneader, a vulcanization system was further added, and the rubber masterbatch component dispersed as a domain in the resin matrix during kneading was dynamically vulcanized. The elastomer composition mixed with a twin-screw kneader is extruded into a strand, the polymer composition is further pelletized with a resin pelletizer, and the pellets are used. A 05 mm film was produced.
The air permeability coefficient and Young's modulus of the obtained film were measured. This film was wound around a drum for forming a tire, and tire members such as a carcass, a side belt, and a tread were laminated thereon and inflated to obtain a green tire. Green tires are cured at 185 ° C for 15 minutes.
Vulcanized at a pressure of 2.3MPa, tire size 165SR
Finished with 13 tires.

On the other hand, as Comparative Example 1, an inner liner layer of about 0.5 mm made of an unvulcanized butyl rubber composition shown in the following composition table was placed on the inner surface of a green tire via a tie rubber having a thickness of about 0.7 mm. Molding a green tire having
Then, it was vulcanized to finish the tire (size 165S
R13).

[0052] * 1: Escorez 1102 manufactured by Esso Chemical Co., Ltd. Also, as Comparative Example 2, a tire was finished in the case where a thermoplastic resin having a critical surface tension difference with an opposing rubber layer of 3 mN / m or less was not used.

The weight of the inner liner layer (air permeation preventing layer) of the resulting pneumatic tire, an air leak test and a tire durability test were performed. The results are shown in Table XV.

[0054]

[Table 15]

[0055]

As described above, according to the present invention,
Prevents air permeation of a polymer composition for tires that maintains good air pressure retention in the tire, maintains flexibility, and has excellent adhesion to rubber, and can reduce the weight of the tire. The pneumatic tire used for the layer can be obtained.

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between the air permeability coefficient and the Young's modulus of the polymer components (A) and (B) according to the present invention and the polymer composition of the present invention.

FIG. 2 is a half sectional view in the meridian direction showing the structure of the pneumatic tire of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Bead core 2: Carcass layer 3: Inner liner layer 4: Side wall

Claims (4)

[Claims] (A) The air permeability coefficient is 25 × 10 ⁻¹² cc
At least one thermoplastic resin having a Young's modulus of not more than 500 MPa and not more than 10% by weight or more based on the weight of all polymer components and (B) an air permeability coefficient of 25 × 10 ⁻¹² cc · cm / cm / cm ² · sec. cm ²・ se
(c) at least one elastomer component having a Young's modulus of not more than 500 MPa and a cmHg of not less than 10% by weight based on the total weight of the polymer component, and the total amount of component (A) and component (B) (A)
+ (B) in an amount of 30% by weight or more based on the weight of all polymer components, and (C) the critical surface tension between the thermoplastic resin of the component (A) and the rubber layer when used as a tire. The difference is 3mN /
m or less, containing 3 to 70% by weight based on the total weight of the components (A), (B) and (C), and having an air permeability coefficient of 25 × 10 ⁻¹² cc · cm / cm ² · sec. A pneumatic tire using a layer of a polymer composition for a tire having a Young's modulus of 1 to 500 MPa at or below cmHg as an air permeation preventing layer. 2. The thermoplastic resin of component (A) is a polyamide resin, a polyester resin, a polynitrile resin, a poly (meth) acrylate resin, a polyvinyl resin, a cellulose resin, a fluorine resin, and an imide resin. The pneumatic tire according to claim 1, wherein the pneumatic tire is at least one thermoplastic resin selected from the group consisting of: 3. The elastomer of component (B) is at least one selected from the group consisting of diene rubbers and hydrogenated products thereof, olefin rubbers, halogen-containing rubbers, silicone rubbers, sulfur-containing rubbers, fluororubbers, and thermoplastic elastomers. The pneumatic tire according to claim 1, which is a kind of elastomer. 4. The pneumatic tire according to claim 1, wherein the elastomer of the component (B) forms a discontinuous phase in the composition.