JPH08217922A - Pneumatic tire - Google Patents

Abstract

PURPOSE: To obtain a pneumatic tire with air permeation inhibiting layers excellent in a balance between air permeation resistance and flexibility and further in adhesion and fit among air permeation preventing layers and between the air permeation preventing layer and rubber and capable of reduction in the weight of tire. CONSTITUTION: This pneumatic tire with air permeation preventing layers 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.%, based on the entire weight of the polymers, 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.%, based on the entire weight of the polymers, an 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 3-50wt.% another thermoplastic resin (C) based on the entire weight of components A, B and C, provided that the total amount of components A and B being at least 30wt.% based on the entire weight of the polymers. The resin C has a melting point equal to or lower than the vulcanization temperature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention has an excellent balance between air permeation resistance and flexibility, and is used for bonding air permeation preventive layers such as inner liner layers during tire molding and vulcanization.
The present invention relates to a pneumatic tire having an air permeation preventive layer which is excellent in adhesiveness and can reduce the weight of the tire by thinning the air permeation preventive layer such as an inner liner layer without impairing the air pressure retention in the tire. .

[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, we do not consider using it as a film.
No mention is made of adhesion. In addition, the inner liner layer has the drawback of being poor 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, even the techniques disclosed in these publications have the drawback that the heat resistance and water resistance of the thin film are poor, and that it is difficult to maintain the uniformity of the film thickness. JP-A-6-40
No. 207 discloses a multilayer film having a low air permeability layer composed of a polyvinylidene chloride film or an ethylene vinyl alcohol copolymer film and an adhesive layer composed of a polyolefin film, an aliphatic polyamide film, or a polyurethane film, and a tire air layer. There is an example of using it as a permeation preventive layer. However, in this system, the low air permeable layer lacks flexibility, the film cannot follow the expansion and contraction of the material during tire running, and cracks may occur, and when these materials are used as a film, it is inevitable. The generated film cannot be joined to the film, and a uniform film cannot be obtained. Therefore, there is a defect that the rubber layer is cracked from the corresponding portion in response to the deformation.

[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, it has an excellent balance of air permeation resistance and flexibility required for the inner liner layer of pneumatic tires, and the spliced part of the inner liner layer (air permeation preventive layer) that is always generated when the tire is molded ( A material excellent in self-bonding property (adhesiveness) under the vulcanization condition between the film at the end overlapping portion) and the film has not yet been developed.

Therefore, an object of the present invention is to make it possible to reduce the weight of a pneumatic tire without impairing the air pressure retention of the pneumatic tire and to have an excellent balance between air permeation resistance and flexibility, and even after the tire is molded. An object of the present invention is to provide a pneumatic tire having excellent self-bonding property (adhesiveness) between films overlaid with a generated air permeation preventive layer.

[0010]

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 (A) + (B) of the components (A) and (B) is 30% by weight or more based on the total weight of the polymer components, and (C) the component (A) 3 to 50% by weight based on the total weight of the components (A), (B) and (C), the other resin having a melting point not higher than the vulcanization temperature, and has an air permeability coefficient of 25 × 10 ^{−. 12} cc ・ cm / cm ²
Provided is a pneumatic tire using, as an air permeation preventive layer, a polymer composition having a Young's modulus of 1 to 500 MPa at a time of not more than sec · cmHg.

According to the present invention, another thermoplastic resin (C) having a melting point not higher than the vulcanization temperature is laminated or coated on the surface of the thin film of the polymer composition comprising the above components (A) and (B). A pneumatic tire having an air permeation preventive layer formed by vulcanization is provided.

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 / or any resin mixture containing them. Further, it may be a thermoplastic resin component in which an antioxidant or the like is added to these.

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 / tetraethylene glycol copolymer, aromatic polyester such as polyoxyalkylene diimide diacid / polybutylene terephthalate copolymer), polynitrile resin (for example, polyacrylonitrile (PAN), polymethacrylate) Ronitrile, acrylonitrile / styrene copolymer (AS), methacrylonitrile / styrene copolymer, methacrylonitrile / styrene / butadiene copolymer),
Poly (meth) acrylate-based resin (for example, polymethylmethacrylate (PMMA), polyethylmethacrylate),
Polyvinyl resin (for example, vinyl acetate, polyvinyl alcohol (PVA), vinyl alcohol / ethylene copolymer (EVOH), polyvinylidene chloride (PVDC), polyvinyl chloride (PVC), vinyl chloride / vinylidene chloride copolymer, vinylidene chloride) / Methyl acrylate copolymer), cellulosic resins (eg cellulose acetate, cellulose acetate butyrate), fluororesins (eg polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF),
Examples thereof include polychlorofluoroethylene (PCTFE), 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.

The elastomer component blended as the component (B) in the resin composition according to the present invention has an air permeability coefficient of 2
Any elastomer greater than 5 × 10 ⁻¹² cc · cm / cm ² · sec · cmHg and Young's modulus of 500 MPa or less, or any blend thereof, or improvement in dispersibility, heat resistance, water resistance, etc. of the elastomer, etc. Reinforcing agents, fillers, cross-linking agents, which are commonly incorporated in elastomers for
An elastomer composition in which a necessary amount of a compounding agent such as a softening agent, an anti-aging agent, and a processing aid is added, and the compounding amount is 10 based on the total weight of the total amount of the polymer components including the resin and rubber constituting the air permeation preventive layer. % By weight or more, preferably 10 to 85
% By weight.

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 (CHC, CHR), 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, as the third component (C), an adhesiveness-imparting component, the thermoplastic resin of the component (A) has a melting point not higher than the vulcanization temperature, preferably not higher than 230 ° C., and other components. The thermoplastic resin is added to the composition in an amount of 3 to 50% by weight, preferably 5 to 35% by weight, based on 100 parts by weight of all components. When this blending amount is small, after vulcanization of the tire molded article, the bonding / adhesiveness between the polymer composition films due to the heat of vulcanization is not sufficient, the bonded part becomes open, and the durability is inconvenient, On the other hand, if the amount is too large, the flowability of the thermoplastic resin makes it difficult to form the tire, and the flow during vulcanization makes it difficult to maintain the film thickness uniformity.

As a specific example of the other thermoplastic resin of the third component (C) according to the present invention, an ultra high molecular weight polyethylene (UHMWPE) having a weight average molecular weight (Mw) of 1,000,000, preferably 3,000,000 or more, Acrylic acid copolymers such as ethylene-acrylic ester copolymer (EEA), ethylene methacrylic acid copolymer (EMA), ethylene-acrylic acid copolymer (EAA) and their maleic anhydride adducts, multi-component Copolyamide resin (PA)
And ethylene-vinyl acetate copolymer (EVA). Here, the multi-component copolymerized polyamide resin means a binary nylon having a specific copolymerization ratio, for example, nylon 6 / nylon 66 (for example, a copolymerization ratio of 70/3.
0-50 / 50), and nylon 6 / nylon 66 /
A ternary or quaternary or higher multi-component copolyamide having a constitution of nylon 610, nylon 6 / nylon 66 / nylon 12, nylon 6 / nylon 66 / nylon 610 / nylon 12, and the like. These multi-component copolyamide-based resins may be used alone or in combination. These multi-component copolyamide resins are commercially available, for example, CM4000, CM4001, CM8000 manufactured by Toray. In addition, polypropylene (PP), ethylene propylene copolymer (EP), styrene-ethylene-butadiene-styrene block copolymer (SEB
S), styrene-butadiene-styrene copolymer (SB
S), styrene-isobutylene-styrene copolymer (S
IBS) and the like.

The composition ratio of the above-mentioned specific thermoplastic resin (A) and elastomer component (B) may be appropriately determined depending on the balance of film thickness, air permeation resistance and flexibility.
The preferred range is 10/90 to 90/10, more preferably 20/80 to 85/15.

As described above, the polymer composition according to the present invention contains the polymer components (A) and (B) having a specific air permeability coefficient and Young's modulus as essential constituent components. 1, the component (A) corresponds to the region X, the component (B) corresponds to the region Y, and the obtained polymer composition corresponds to the region Z in FIG.

In the present invention, the heat resistance belonging to component (A)
Plastic resin A₁~ A_nAnd the average value Aav of these
(= ΣφiA₁(I = 1 to n), where φi is A₁The weight of
%)). This point Aav and the air permeability coefficient are 25 ×
10^-12cc / cm / cm²・ Sec ・ cmHg, Young's modulus 500MP
It can be formed by connecting the point P of a with a straight line and extrapolating the straight line AavP.
Below the straight line and air permeability coefficient 25 × 10^-12cc / cm /
cm²・ Sec ・ It belongs to Y area in area S of cmHg or more
(B) component, B₁~ B_nAverage value Bav (= ΣφiB ₁
(I = 1 to n), where φi is B₁(% By weight)
To select such an elastomer and mix it in an appropriate formulation
It is possible to obtain a polymer composition that falls within the desired zone Z.
Wear.

The polymer composition used in the present invention is further blended with the above-mentioned specific thermoplastic resin (C), and the obtained polymer composition must have the above-mentioned specific air permeability coefficient and Young's modulus. I have to.

When the tire polymer composition of the present invention is adhered to rubber, it goes without saying that a surface treatment of the rubber with a halogen-containing compound or an adhesive such as a chlorinated rubber type, an isocyanate type or a phenol resin type can be used. Further, in the present invention, a thermoplastic resin other than the third component (C) may be added, and a material generally called a compatibilizer may be used together in order to reinforce the adhesive force with the rubber. The compatibilizing agent may be one that acts by bringing the surface energy between layers closer to each other, or one that has a reactive functional group. A carbonyl group, a halogen group, a hydroxyl group, an amino group, an epoxy group and the like are preferably used as the reactive group. As the main compatibilizing agent, maleic acid-modified polyolefin, a polymer obtained by graft-polymerizing acrylic acid or glycidyl methacrylate to polyolefin, a block copolymer of polyolefin and nylon, and a maleic acid of styrene-ethylene-butadiene-styrene copolymer. Examples include modified products and the like.

The pneumatic tire having the air permeation preventive layer according to 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 arrangement is not a problem as long as 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 cross-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 (air permeation preventive 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 is carried out by previously using the thermoplastic resin (A).
And (C) and the elastomer (unvulcanized product in the case of rubber) component (B) are melt-kneaded by a twin-screw kneading extruder or the like to disperse the elastomer component in the thermoplastic resin forming the continuous phase. Furthermore, (A) and (B) may be melt-kneaded and then (C) may be continuously added to complete a similar structure. 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. Furthermore, 2
Kneading machines of more than one kind 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 2500.
It is preferably ˜7500 Sec ⁻¹ . The total kneading time is 30 seconds to 10 minutes, and when a vulcanizing agent is added,
The vulcanization time after addition is preferably 15 seconds to 5 minutes. The polymer composition produced by the above method is extruded in a strand shape by a twin-screw kneading extruder, pelletized by a resin pelletizer, and formed into a film by sheet molding or calendar molding by the resin extruder using the pellets. . 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 impart 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. Therefore, it becomes 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. Explaining an example, the polymer composition of the present invention can be extruded in advance into a thin film having a predetermined width and thickness, and the thin film can be adhered onto a tire molding drum in a cylindrical shape with its end portions overlapping. 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 pressure vulcanization at a temperature of, for example, 150 to 230 ° C. 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 after vulcanization according to the present invention is
Air permeability coefficient is 25 × 10 ^-12 cc ・ cm / cm ²・ sec ・ cm
Hg or less, preferably 5 × 10 ⁻¹² cc · cm / cm ² · sec
It is below cmHg. Air permeability coefficient is 25 × 10 ^-12 cc · cm
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 by controlling the thickness to be / cm ² · 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 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.

[0034]

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". Test piece: The film sample prepared in each example was punched with a JIS No. 3 dumbbell in parallel with the flow direction at the time of film molding extrusion. 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.

Melting Point Measuring Method Each resin pellet was measured by differential scanning calorimetry (DSC), and the endothermic peak was taken as the melting point. If the endothermic peak at the melting point is unclear, it can be measured with a thermomechanical analysis (TMA) device at 5 ×.
A load of 1 g was applied to a 5 × 15 mm test piece to measure the heat distortion temperature, which was used as a reference value for DSC data. Heating rate is 1
It was set to 0 ° C./min.

Air permeation preventive layer Weighing pellets were melted by an extruder for resin to give a width of 350 m.
A film having a thickness of m and a thickness of 0.05 mm was prepared and its weight was measured.

The pressure decrease rate of the film of the formulation of each example was used for the inner liner, after mounting on the rim of size 13 × 41/2 -J, conducted air leakage test, with a pressure drop rate of the tire.

Durability In order to examine the effect of fusion bonding of 40 mm seams provided on the inner liner layer, a seam (splice) durability test was conducted under conditions of a vulcanization temperature of 185 ° C. and a pressure of 2.3 MPa.
SR13 steel radial tire (rim 13 × 41 /
2-J) under test conditions (air pressure 140 kPa, load 5.5 kN, room temperature 38 ° C.), it was run on a φ1707 mm drum at a speed of 80 km / h for 10,000 km, and the splice part of the tire innerliner layer was used. , If the following failures are found by visual inspection, they are rejected. 1) Open mouth at the joint 2) There is peeling or rising at the joint and its vicinity

Sheet shape retention The presence or absence of shape retention of the sheet itself at the time of vulcanization of the tire was evaluated as follows based on the stability of the inner liner thickness of the tire after vulcanization. Carcass layer (carcass code: 1500d / 2, PET
A liner with a thickness of 0.05 mm was laminated on the surface of a driving density: 50 ends / 50 mm width, thickness: 1.0 mm, and this was hot-pressed (2300 kPa, 185 ° C. × 15 minutes), and after vulcanization The inner liner gauge of the sample is measured, and from the maximum value (Tmax) and the minimum value (Tmin), the formula: [(Tmax-Tmin) / ((Tmax + Tmin)
/ 2)] was used to determine the thickness stability of the inner liner. This value is
It is preferably 0.2 or less. The uniformity of the inner liner thickness is indispensable from the following viewpoints. 1) When it is non-uniform, the air leaks more easily than the thin portion, and the air leak resistance is poor. 2) Due to the unevenness of the tire vulcanization bladder and the carcass cord, if the fluidity of the liner material is high at the temperature during vulcanization, it becomes uneven. 3) If there are large variations in the liner gauge, air leakage resistance can be maintained by increasing the initial thickness accordingly.
It is meaningless to increase the cage by 20% or more from the viewpoint of cost and weight reduction.

Examples 1 to 8 and Comparative Examples 1 to 2 (A) Thermoplastic resin component and (C) Adhesion-imparting resin component in various formulations (parts by weight) shown in Table I were mixed in a twin-screw kneading extruder. 1) An input port, kneading and melting, then (B) elastomer component is input and kneading from the second input port (B) is a dispersed phase, and components (A) and (C) are a continuous layer. Kneaded. The kneaded product was extruded in a strand form from the tip of a twin-screw kneading extruder, cooled with water, and pelletized using a pelletizer for resin. The pellets were formed into a film having a width of 350 mm and a thickness of 0.05 mm by using a resin extruder. This film was wound on a tire forming drum, and a tire member such as a carcass, a side, a belt and a tread was laminated on the film and inflated to obtain a green tire.
The green tire was vulcanized with a vulcanizer at 185 ° C. for 15 minutes at a pressure of 2.3 MPa to obtain a tire size of 165SR13.
Finished with the tire. Various performances of the above film and tire were evaluated, and the results are shown in Table I.

Comparative Example 3 A green tire having an inner liner layer of about 0.5 mm made of unvulcanized butyl rubber having the composition shown in the table below was provided on the inner surface of the green tire with a tie rubber having a thickness of about 0.7 mm interposed therebetween. It was molded and then vulcanized to finish the tire (size 165SR13). Butyl rubber compound (unit: parts by weight) ──────────────────────────
─ Br-IIR 100 Carbon Black (GPF) 60 Stearic Acid 1 Petroleum Hydrocarbon Resin ^{* 1} 10 Paraffin Process Oil 10 3 ZnO 3 DM 1 Sulfur 0.6 ────────────── ─────────────
-* 1 ... Escoletz 1102 manufactured by Esso Chemical Co., Ltd. The evaluation results are shown in Table I.

[0044]

[Table 1]

[0045]

[Table 2]

Examples 9 to 17 and Comparative Examples 4 to 6 Films and thermoplastic resins obtained in the same manner as in Examples 1 to 8 and Comparative Examples 1 to 3 except that the elastomer component was replaced by Br-IIR were PBT. Then, the film obtained by using Br-IIR as the elastomer component was finished in the same manner as in Example 1. The tire performance was evaluated and the results are shown in Table II.

[0047]

[Table 3]

[0048]

[Table 4]

Examples 18 to 20 Various compounding agents were mixed with Br-IIR and Br-IPMS except for the vulcanizing compounding agent, and master batches A and B were prepared in a closed type Banbury mixer for rubber. A masterbatch of the rubber composition is formed into a sheet having a thickness of 3 mm by using a rubber roll, and the formulation of the masterbatch pelletized by using a rubber pellet making machine is shown in Table III.

[0050]

[Table 5]

(A) Thermoplastic resin component and (C) Adhesion-imparting resin component in various formulations (parts by weight) shown in Table IV were charged from the first charging port of the twin-screw kneading extruder and kneaded and melted. Then, the master batch (B) was charged through the second charging port and kneaded so that (B) became the dispersed phase and the components (A) and (C) became the continuous phase. Further, a vulcanization-based compounding agent or the like is charged from the third charging port to crosslink the dispersed elastomer layer.
Cured. The kneaded product was extruded in a strand form from the tip of a twin-screw kneading extruder, cooled with water, and pelletized using a pelletizer for resin. The pellets were formed into a film having a width of 350 mm and a thickness of 0.05 mm by using a resin extruder. The air permeation prevention coefficient and Young's modulus of the obtained film were measured. Further, these films were wound on a drum for tire formation, and tire members such as carcass, sides, belts and treads were laminated thereon and inflated to obtain a green tire. The green tire is 185 ° C with a vulcanizer,
The tire was vulcanized at a pressure of 2.3 MPa for 15 minutes to finish a tire having a tire size of 165SR13. The weight measurement and air leakage test of the inner liner layer of the obtained pneumatic tire were performed. The results are shown in Table IV.

[0052]

[Table 6]

[0053]

As described above, according to the present invention,
While maintaining good air pressure retention in the tire and maintaining flexibility, it also has excellent adhesion with rubber, and also has excellent adhesion between layers such as a liner layer during tire molding. It is possible to obtain a pneumatic tire having an air permeation preventive layer, which can reduce the weight.

[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) and the polymer composition according to the present invention.

FIG. 2 is a meridional direction half cross-sectional view showing a typical structure of the pneumatic tire of the present invention.

[Explanation of symbols]

 1 ... Bead core 2 ... Carcass layer 3 ... Inner liner layer 4 ... Sidewall

Claims (6)

[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 thermoplastic resin of the component (A) contains another thermoplastic resin having a melting point not higher than the vulcanization temperature ( 3 to 50% by weight based on the total weight of components A), (B) and (C), having an air permeability coefficient of 25 × 10 ⁻¹² cc · cm / cm ² · sec · cmHg or less and a Young's modulus of 1 to 500 MPa. A pneumatic tire comprising a tire polymer composition as an air permeation preventive layer. 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 pneumatic tire 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 pneumatic tire according to claim 1, which is a kind of elastomer. 4. The pneumatic tire according to claim 1, wherein the elastomer of 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・ sec ・ cmHg and Young's modulus is 50
At least one elastomer component of 0 MPa or less is 10% by weight or more based on the weight of all polymer components, and the total amount (A) + (B) of the components (A) and (B) is 30% by weight or more based on the weight of all polymer components. Air permeability coefficient is 2 including quantity
^{5 × 10 -1 2 cc · cm} / cm 2 · sec · cmHg or less at Young's modulus melting point on the surface of the thin film of the tire polymer composition for 1~500MPa vulcanization temperatures less of other thermoplastic resin (C) A pneumatic tire having an air permeation preventive layer obtained by laminating or coating and vulcanizing. 6. The thermoplastic resin as the component (C) is a copolyamide resin, ultra high molecular weight polyethylene, polypropylene, ethylene-propylene copolymer, styrene-ethylene-butadiene-styrene block copolymer, ethylene-acryl. The pneumatic tire according to any one of claims 1 to 5, which is at least one selected from the group consisting of an ester copolymer and an ethylene-vinyl acetate copolymer.