JPH08217923A - Polymer composition for tire and pneumatic tire made thereof - Google Patents

Abstract

PURPOSE: To obtain a polymer composition which can give a lightweight tire when used as the air permeation preventing layer of a pneumatic tire, excellent in a balance between air permeation resistance and flexibility and adhesion of the layer and rubber. CONSTITUTION: This polymer composition for a tire having an air permeability coefficient of 25×10<-12> cc.cm/cm<2> .sec.cmHg or below and a Young's modulus of 1-500MPa comprises at least 10wt.% thermoplastic resin (A) having an air permeability coefficient of 25×10<-12> cc.cm/cm<2> .sec.cmHg or below and a Young' s modulus of above 500MPa, at least 10wt.% elastomer (B) having an air permeability coefficient of above 25×10<-12> cc.cm/cm<2> .sec.cmHg and a Young's modulus of 500MPa or below, and 3-70wt.% another thermoplastic resin (C) based on components A, B and C, provided that the entire amount of components A and B being 30wt.% 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 3mN/m or below.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tire polymer composition having an excellent balance between air permeation resistance and flexibility, and further having excellent adhesion to rubber. The present invention relates to a polymer composition for a tire, which can reduce the weight of a tire by thinning an air permeation preventive layer such as an inner liner layer without impairing the air pressure retention property, and a pneumatic tire using the same as a pneumatic permeation preventive layer.

[0002]

2. Description of the Related Art Reducing the fuel consumption rate is one of the major technical problems in automobiles, and as part of this measure, there is an increasing demand for weight reduction of pneumatic tires.

By the way, an inner liner layer made of rubber having low gas permeability such as butyl rubber is provided on the inner surface of the pneumatic tire in order to keep the tire air pressure constant. However, since halogenated butyl rubber has a large hysteresis loss, after vulcanization of the tire,
When the inner surface 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, which causes a problem of increased rolling resistance. Therefore, in general, the inner liner layer (halogenated butyl rubber) and the inner surface rubber of the carcass layer are joined together via a rubber sheet called tie rubber having a small hysteresis loss. Therefore, in addition to the thickness of the inner liner layer of halogenated butyl rubber, the thickness of tie rubber is added, resulting in a layer thickness of more than 1 mm (1000 μm), resulting in an increase in the weight of the product tire. It was one.

Techniques have been proposed in which various materials are used as an inner liner layer of a pneumatic tire in place of low gas permeability rubber such as butyl rubber. For example,
-31761 discloses that the inner surface of a vulcanized tire has an air permeability coefficient [cm ³ (standard state) / cm · sec · mmHg] of 1 at 30 ° C.
It is disclosed that a solution or dispersion of synthetic resin such as polyvinylidene chloride, saturated polyester resin, polyamide resin or the like having a concentration of 0 × 10 ⁻¹³ or less and 50 × 10 ⁻¹³ or less at 70 ° C. is applied in an amount of 0.1 mm or less. There is.

However, the technique disclosed in this publication is
It is stated that a synthetic resin coating layer having a specific air permeability coefficient is provided on the inner peripheral surface of the carcass of the vulcanized tire or on the inner peripheral surface of the inner liner so that the thickness of the synthetic resin coating layer is 0.1 mm or less. However, the pneumatic tire described in this publication has a problem that the rubber and the synthetic resin film have a problem of adhesion, and 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 liquid, a bromine solution and an iodine solution), and a methoxymethylated nylon, Polymer film of polymerized nylon, blend of polyurethane and polyvinylidene chloride, blend of polyurethane and polyvinylidene fluoride (film thickness 1
0-200 μm) is disclosed.

Further, in Japanese Patent Laid-Open No. 5-318618,
A pneumatic tire using a methoxymethylated nylon thin film as an inner liner is disclosed. According to this technique, a methoxymethylated nylon solution or emulsion is sprayed or applied on 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 onto the inner surface of the tire after vulcanization. However, the technique disclosed in this publication also has a drawback that it is difficult to maintain the uniformity of the film thickness, in addition to the defect that the thin film has poor water resistance.

[0008]

As mentioned above, various materials for the inner liner layer of pneumatic tires have been proposed in place of butyl rubber, but they have not yet been put to practical use. In particular, a material having an excellent balance between air permeation resistance and flexibility, which is necessary for an inner liner layer of a pneumatic tire, and an excellent adhesiveness with rubber has not yet been developed. Therefore, the object of the present invention is to enable the weight reduction of the tire without impairing the air pressure retaining property of the pneumatic tire, and excellent balance with air permeation resistance and flexibility, and also the adhesiveness with the rubber layer. (EN) Provided is a polymer composition for a tire, which is most suitable for an air permeation preventive layer of a pneumatic tire, and a pneumatic tire comprising the air permeation preventive layer using the same.

[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 more than 500 MPa and Hg or less and 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 ²
・ Sec ・ At least one elastomer component with Young's modulus of 500MPa or less and cmHg or more is 1 per weight of all polymer components.
0% by weight or more, the total amount of the components (A) and (B) (A) + (B) is 30% by weight or more based on the total weight of all polymer components, and (C) the above ( When the thermoplastic resin of the component (A) is used as a tire, the other thermoplastic resin having a critical surface tension difference of 3 mN / m or less with the opposing rubber layer is the sum of the components (A), (B) and (C). 3 ~ per weight
Containing 70% by weight, the air permeability coefficient of 25 × 10 ^{-1 2} cc ·
cm / cm ² · sec · cmHg and Young's modulus is 1 to 500 MPa
The tire polymer composition is provided.

According to the present invention, there is also provided a pneumatic tire using the above polymer composition for a tire in an air permeation preventive layer.

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, Young's modulus is more than 500MPa, preferably 500
Any thermoplastic resin of up to 3000 MPa can be used, and the compounding 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 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.

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 (eg polybutylene terephthalate (PBT), polyethylene terephthalate (PET) ), Polyethylene isophthalate (PEI), PET / PEI copolymer, polyarylate (PAR), polybutylene naphthalate (PB)
N), liquid crystal polyester, polybutylene terephthalate / polytetramethylene glycol copolymer, aromatic polyester such as polyoxyalkylene diimide diacid / polybutylene terephthalate copolymer), polynitrile resin (for example, polyacrylonitrile (PAN), poly Methacrylonitrile, acrylonitrile / styrene copolymer (AS), methacrylonitrile / styrene copolymer,
Methacrylonitrile / styrene / butadiene copolymer), poly (meth) acrylate resin (eg polymethylmethacrylate (PMMA), polyethylmethacrylate), polyvinyl resin (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 Union), cellulosic resin (eg, cellulose acetate, cellulose acetate butyrate), fluorine resin (eg, polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), polychlorofluoroethylene (P)
Examples thereof include CTFE), tetrafluoroethylene / ethylene copolymer (ETFE), and imide resin (for example, aromatic polyimide (PI)).

As described above, these thermoplastic resins must have a specific air permeability coefficient, Young's modulus and blending amount. It has a Young's modulus of less than 500MPa and an air permeability coefficient of 25 × 10 ^-12 cc · cm / cm ² · sec · cmHg.
The following materials have not yet been 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 of the polymer composition for tires decreases, and the tire does not function as an air permeation preventive layer. Further, when the blending amount of these thermoplastic resins is less than 10% by weight, the air permeation resistance is similarly reduced, and it cannot be used as an air permeation preventive layer of a tire, which is not preferable.

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, and anti-aging agents that are generally blended with the elastomer to improve the dispersibility and heat resistance of the elastomer. An elastomer composition in which a necessary amount of a compounding agent such as an agent and a processing aid is added, and the compounding amount is 10% by weight or more based on the total weight of the total amount of the resin component forming the air permeation preventive layer and the polymer component including the elastomer component, The amount is preferably 10 to 85% by weight, and the total amount of the components (A) and (B) (A) + (B) is 30% by weight or more based on the total weight of the 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, but examples thereof include the following.

Diene rubbers and hydrogenated products thereof (eg 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 (for example, methyl vinyl silicone rubber, dimethyl silicone rubber, methylphenyl vinyl silicone rubber), sulfur-containing rubber (for example, polysulfide rubber), fluororubber (for example, vinylidene fluoride-based rubber, fluorine-containing vinyl ether-based rubber) , Tetrafluoroethylene-propylene rubber, fluorine-containing silicon rubber, fluorine-containing phosphazene rubber), thermoplastic elastomer (for example, styrene elastomer, olefin elastomer, polyester elastomer) Urethane elastomers, polyamide elastomers), and the like.

According to the present invention, a thermoplastic resin having a critical surface tension difference (Δγc) between the rubber layers facing each other when used as a tire is 3 mN / m or less is further used as an adhesiveness-imparting component of the third component. 3 to 70% by weight, preferably 3 to 50% by weight, based on the total weight of the components (A), (B) and (C), is added to the composition. If this blending amount is too small, the adhesion to the opposing components will not be sufficient, and conversely if it is too large, the air permeability coefficient will be too large and 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 ultra high 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 so on.

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

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

In the present invention, the thermoplastic resins A _{1 to} A _n belonging to the component (A) are determined and their average value Aav is determined.
(= ΣφiAi (i = 1 to n), where φi is the weight% of Ai). This 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, and the lower side of the straight line formed by extrapolating the straight line AavP and the air permeability coefficient 25 × 10 ⁻¹² cc · cm /
The average value Bav (= ΣφiBi) of the (B) component belonging to the Y region and B _{1 to} B _n in the region S of cm ² · sec · cmHg or more.
(I = 1 to n), where φi is the weight% of Bi), select an elastomer, mix with an appropriate composition, and further
Component (C) can be added to obtain a polymer composition that falls within the desired zone Z.

The pneumatic tire having the air permeation preventive layer produced by using the polymer composition for a tire of the present invention will be described in more detail below. The air permeation preventive layer of the pneumatic tire according to the present invention can be arranged at any position inside the tire, that is, inside or outside the carcass layer, or at any other position. In short, the object of the present invention is achieved by arranging the tire so that the air pressure inside the tire can be prevented and the air pressure inside the tire can be maintained for a long period of time.

FIG. 2 is a meridional direction half-sectional view illustrating a typical example of the arrangement of the air permeation preventive layer of a 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, 4 indicates a sidewall.

In the present invention, the method for producing the polymer composition constituting the air permeation preventive layer comprises a thermoplastic resin component and an elastomer (unvulcanized product in the case of rubber) components which are components (A) and (C) in advance. (B) is melt-kneaded with a twin-screw kneading extruder or the like to disperse the elastomer component in the thermoplastic resin forming the continuous phase. When vulcanizing the elastomer component, a vulcanizing agent may be added under kneading to dynamically vulcanize the elastomer. Further, various compounding agents (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 in advance before the kneading. The kneading machine 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. Above all, it is preferable to use a twin-screw kneading extruder for kneading the resin component and the rubber component and dynamically vulcanizing the rubber component. Further, two or more kinds of kneaders may be used and kneading may be sequentially performed. As a condition for melt-kneading, the temperature may be equal to or higher than 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 if a vulcanizing agent is added, the vulcanization time after addition is 15 seconds to 5 minutes.
Minutes are 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 based on a method of forming a film of a usual thermoplastic resin or thermoplastic elastomer. 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 the matrix of the thermoplastic resins (A) and (C). By adopting a dispersion structure in such a state, it is possible to give a balance between flexibility and air permeation resistance, and it is possible to obtain effects such as improved heat distortion resistance and improved water resistance, and thermoplastic processing. Since it becomes possible, it is possible to form a film by a usual resin molding machine, that is, extrusion molding or calender molding. The method of forming a film may be a method of forming an ordinary thermoplastic resin or thermoplastic elastomer into a film.

Regarding the method for manufacturing a pneumatic tire having an air permeation preventive layer comprising a thin film of the polymer composition according to the present invention, as shown in FIG. 2, when the inner liner layer 3 is arranged inside the carcass layer 2, To explain one example,
The polymer composition of the present invention is extruded in advance into a thin film having a predetermined width and thickness, which can be adhered to a cylinder on a tire molding drum. Members such as a carcass layer made of unvulcanized rubber, a belt layer, and a tread layer, which are used in ordinary tire manufacturing, are successively laminated on top of this, and the drum is removed to obtain a green tire. Then, the desired lightweight pneumatic tire can be manufactured by subjecting this green tire to heat vulcanization according to a conventional method. When the air permeation preventive layer is provided on the outer peripheral surface of the carcass layer, it can be performed in accordance with this.

The material of the rubber layer to which the air permeation preventive layer according to the present invention is adhered is not particularly limited, and any rubber material conventionally used as a rubber material for tires can be used. Examples of such rubber 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, a compounding agent such as a plasticizer and a vulcanizing agent to a styrene elastomer.

The air permeation preventive layer according to the present invention has an air permeation coefficient of 25 × 10 ⁻¹² cc · cm / cm ² · sec · cmHg or less,
It is preferably 5 × 10 ⁻¹² cc · cm / cm ² · sec · cmHg or less. Air permeability coefficient of 25 × 10 ^-12 cc ・ cm / cm ²・
By setting sec · cmHg or less, the thickness of the air permeation preventive layer can be reduced to 1/2 or less of the thickness of the conventional air permeation preventive layer.

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 1 MPa
When it is less than 500 MPa, it is not preferable because handling becomes difficult due to wrinkles during tire molding. On the contrary, when it exceeds 500 MPa, it is not preferable because the tire deformation during running cannot be followed.

[0030]

EXAMPLES The present invention will be described in more detail below 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.

Film air permeation coefficient measurement method: JIS K7126 “Plastic film and sheet gas permeation test method (method A)” was followed. Test piece: The film sample prepared in each example was used. Test gas: Air (N ₂ : O ₂ = 8: 2) Test temperature: 30 ° C

The Young's modulus of the film was measured in accordance with JIS K6251 "Tensile test method for vulcanized rubber". Specimen: A film sample prepared by extrusion molding in each example was placed in parallel with the resin flow direction during extrusion according to JIS.
I punched it out with No. 3 dumbbell. A tangent line was drawn on the curve of the initial strain region of the obtained stress-strain curve, and Young's modulus was obtained from the slope of the tangent line.

Evaluation Method of Fusing Property with Rubber A 2 mm sheet of each resin was hot-pressed at a pressure of 3 MPa,
Pressed in 20 minutes. The temperature at that time was set to the melting point of each resin + 20 ° C. The sheet is 1 inch wide, JI
When the peeling test was performed according to SK6256, the material that failed was rated as ◯, and the material that showed no peeling force was rated as x. The case where there was a peeling force but interfacial peeling was evaluated as Δ.
The rubber used at this time is SBR / NR = 50 parts: 50
In the part system, the γc was 30 mN / m.

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

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

Examples 1 to 14 One or two kinds of each of the various thermoplastic resin components (A) and (C) and the elastomer component (B) at various compounding ratios (parts by weight) shown in Tables I to XIV. In some cases, other components such as a vulcanizing agent and a lubricant are kneaded in a twin-screw kneader and then continuously pelletized by a pelletizer for resin, and then using the pellets, a width of 350 mm in an extruder for resin, The film was 0.1 mm thick. The air permeability coefficient and Young's modulus of the obtained film were measured, and the results are shown in Tables I to XIV.

[0037]

[Table 1]

[0038]

[Table 2]

[0039]

[Table 3]

[0040]

[Table 4]

[0041]

[Table 5]

[0042]

[Table 6]

[0043]

[Table 7]

[0044]

[Table 8]

[0045]

[Table 9]

[0046]

[Table 10]

[0047]

[Table 11]

[0048]

[Table 12]

[0049]

[Table 13]

[0050]

[Table 14]

Examples 15 and 16 and Comparative Examples 1 and 2 Br-IIR or Br-poly (isobutylene-p-methylstyrene) (Br-IPMS) was mixed with various compounding agents in a closed Banbury mixer for rubber. Kneading was performed, and then a rubber roll was used to form a rubber sheet having a thickness of 2.5 mm to prepare master batches A and B. The sheet of the masterbatch A or B was pelletized with a pelletizer for rubber, and the pellets were used to biaxially mix the components (A) and (C) with the masterbatch at various blending ratios (parts by weight) shown in Table XV. After kneading with a kneader, a vulcanization system was further added to dynamically vulcanize the rubber masterbatch component dispersed as domains in the resin matrix during kneading. The elastomer composition mixed by a twin-screw kneader is extruded into a strand, the polymer composition is further pelletized by a pelletizer for resin, and the pellet is used by an extruder for resin to have a width of 350 mm and a thickness of 0. A 05 mm film was made.
The air permeability coefficient and Young's modulus of the obtained film were measured. This film was wound on a tire molding drum, and a tire member such as a carcass, a side belt and a tread was laminated on the drum and inflated to obtain a green tire. Green tires are vulcanized at 185 ° C for 15 minutes,
Vulcanized at a pressure of 2.3 MPa, tire size 165SR
Finished 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 formulation table was provided on the inner surface of a green tire with a tie rubber of about 0.7 mm interposed. Mold the green tires you have,
Then, it was vulcanized to finish the tire (size 165S
R13).

Butyl rubber compound (unit: parts by weight) ──────────────────── Br-IIR 100 Carbon black (GPF) 60 Stearic acid 1 Petroleum hydrocarbon resin ^{* 1} 10 Paraffin-based process oil 10 3 No. ZnO 3 DM 1 Sulfur 0.6 ──────────────────── * 1: Essolets 1102 manufactured by Esso Chemical Co., Ltd. As No. 2, a tire was finished in the case where a thermoplastic resin having a critical surface tension difference of 3 mN / m or less from the opposing rubber layer was not used.

The weight of the inner liner layer (air permeation preventive layer) of the obtained pneumatic tire, the air leakage test and the tire durability test were carried out. The results are shown in Table XV.

[0055]

[Table 15]

[0056]

As described above, according to the present invention,
An air permeation preventive layer for a pneumatic tire, which maintains good air pressure retention in the tire, maintains flexibility, and has excellent adhesiveness with rubber, which makes it possible to reduce the weight of the tire. A suitable polymer composition for tires can be obtained.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between air permeability coefficient and Young's modulus of 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 Codes] 1 ... Bead core 2 ... Carcass layer 3 ... Inner liner layer 4 ... Sidewall

Claims (5)

[Claims] 1. (A) Air permeability coefficient is 25 × 10 ^-12 cc
・ Cm / cm ²・ sec ・ cmHg or less and Young's modulus of more than 500 MPa, at least one kind of thermoplastic resin is 10% by weight or more based on the weight of all polymer components, and (B) the air permeability coefficient is 25 × 10 ^-12 cc ・ cm / cm ² · se
c. At least one elastomer component having a Young's modulus of 500 MPa or less and a content of more than 10% by weight based on the total weight of the polymer components and a total amount (A) of the component (A) and the component (B).
+ (B) is contained in an amount of 30% by weight or more based on the total weight of the polymer components, and (C) the critical surface tension between the thermoplastic resin of the component (A) and a rubber layer facing each other when used as a tire. The difference is 3 mN /
m The following other thermoplastic resin (A), (B) and (C) including a total weight per 3 to 70% by weight of component, the air permeability coefficient of ^{25 × 10 -1 2 cc · cm} / cm 2 · A polymer composition for tires having a Young's modulus of 1 to 500 MPa at a sec · cmHg or less. 2. The thermoplastic resin as the 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 tire polymer composition according to claim 1, which is at least one thermoplastic resin selected from the group consisting of: 3. The component (B) elastomer is at least 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 tire polymer composition according to claim 1 or 2, which is a kind of elastomer. 4. The resin composition according to claim 1, wherein the elastomer as the component (B) forms a discontinuous phase in the composition. 5. (A) Air permeability coefficient is 25 × 10 ^-12 cc
・ Cm / cm ²・ sec ・ cmHg or less and Young's modulus of more than 500 MPa, at least one kind of thermoplastic resin is 10% by weight or more based on the weight of all polymer components, and (B) the air permeability coefficient is 25 × 10 ^-12 cc ・ cm / cm ² · se
c. At least one elastomer component having a Young's modulus of 500 MPa or less and a content of more than 10% by weight based on the total weight of the polymer components and a total amount (A) of the component (A) and the component (B).
+ (B) is contained in an amount of 30% by weight or more based on the total weight of the polymer components, and (C) the critical surface tension between the thermoplastic resin of the component (A) and a rubber layer facing each other when used as a tire. The difference is 3 mN /
An air permeability coefficient of 25 × 10 ⁻¹² cc · cm / cm ² · sec, which contains 3 to 70% by weight of the other thermoplastic resin of m or less based on the total weight of the components (A), (B) and (C). A pneumatic tire using a layer of a tire polymer composition having a Young's modulus of 1 to 500 MPa at cmHg or less as an air permeation preventive layer.