WO2014024547A1

WO2014024547A1 - Pneumatic tire

Info

Publication number: WO2014024547A1
Application number: PCT/JP2013/064910
Authority: WO
Inventors: 剛史土田; 睦樹杉本
Original assignee: 住友ゴム工業株式会社
Priority date: 2012-08-07
Filing date: 2013-05-29
Publication date: 2014-02-13

Abstract

This pneumatic tire has an inner liner that is formed of a polymer laminate. The polymer laminate comprises a first layer which is formed of a first polymer A composition containing SIBS and has a thickness of from 0.05 mm to 0.8 mm (inclusive) and a second layer that is formed of a second polymer A composition containing SIS and/or SIB and has a thickness of from 0.01 mm to 0.8 mm (inclusive). The first polymer A composition and/or the second polymer A composition contains an epoxidized styrene-butadiene-styrene triblock copolymer in an amount of from 0.5% by mass to 40% by mass (inclusive). The second layer is arranged so as to be in contact with a rubber layer of a carcass ply. With respect to the inner liner, the thickness (Ge) thereof at the shoulder position (Pe) is larger than the thickness (Gc) thereof at the crown center position (Pc), and the thickness (Ge) is from 0.2 mm to 1.9 mm (inclusive).

Description

Pneumatic tire

The present invention relates to a pneumatic tire provided with an inner liner.

The inner liner is disposed on the inside of the tire, and has a function of reducing air leakage from the inside to the outside of the pneumatic tire to maintain the tire internal pressure constant. As a material having such a function, rubber compositions having low gas permeability such as butyl-based rubber are conventionally used. On the other hand, in order to reduce the weight of the tire, a film made of a material containing a thermoplastic resin may be used instead of the butyl rubber composition.

Here, in the inner liner, a large shear strain acts in the vicinity of the shoulder portion when the tire is used. When a material containing a thermoplastic resin is used as an inner liner, there is a problem that this shear strain easily causes peeling at the bonding interface between the inner liner and the carcass ply, which causes air leakage of the tire.

On the other hand, pneumatic tires are required to have low fuel consumption, and there is a problem of reducing rolling resistance by reducing the weight of the tires. Therefore, a technology using a thermoplastic elastomer for the inner liner is also proposed, but if the thickness is made thinner than the butyl rubber inner liner, the strength of the inner liner decreases and the heat and pressure of the bladder during the vulcanization process There was a problem that the inner liner was broken or deformed.

Furthermore, it has been found that the thermoplastic elastomer having high air permeation resistance is inferior in vulcanization adhesion to insulation rubber and carcass rubber adjacent to the inner liner than butyl rubber. If the vulcanization adhesion of the inner liner is low, air is entrapped between the inner liner and insulation rubber or carcass rubber, causing a so-called air-in phenomenon in which something like a small balloon appears. Although there is no problem in the performance of the tire, the presence of the air-in gives the user the impression that the appearance is bad.

JP-A-9-019987 (Patent Document 1) discloses a polyamide-based resin and a polyester-based resin as a laminate suitable for a pneumatic tire having an air permeation preventing layer such as an inner liner layer or the like, which keeps air pressure constant. And at least one of a gas barrier layer (A) and an adhesive layer (B) selected from the group consisting of polyarylate resins, polyamide alloys and polyester alloys, in at least two layers, There is disclosed a laminate of a laminate film and a rubber layer, which comprises a laminate film irradiated with an electron beam from the surface, and the adhesive layer (B) is heat-bonded to the rubber layer (R).

The laminate has a problem in that the adhesive layer comes into contact with the bladder in a heated state in the vulcanization step and adheres to the bladder.

Japanese Patent No. 2999188 (Japanese Patent Laid-Open No. 2000-159936, Patent Document 2) describes a thermoplastic elastomer composition (A) as a dispersed phase, a thermoplastic resin composition (a thermoplastic resin composition (A) as a thermoplastic elastomer composition having air resistance. A thermoplastic elastomer composition is disclosed in which B) is a matrix and the thermoplastic resin composition is a blend of two or more thermoplastic resins. In the examples, nylon resin is used as the thermoplastic resin composition, but nylon resin is hard at room temperature and unsuitable as an inner liner for tires. Furthermore, the thermoplastic elastomer composition does not adhere to the rubber layer by vulcanization. Therefore, when the thermoplastic elastomer is used for the inner liner, an adhesive layer for vulcanization is further required, which is disadvantageous from the viewpoint of productivity.

JP-A 2008-024219 (patent document 3) discloses that maleic anhydride modified hydrogenated styrene-ethylene-butadiene-styrene block copolymer is dispersed in a good air-blocking ethylene-vinyl alcohol copolymer. Also, a flexible gas barrier layer is disclosed. Also disclosed is an inner liner layer produced by sandwiching the gas barrier layer with a thermoplastic polyurethane layer and further applying a rubber paste (70/30 of butyl rubber / natural rubber dissolved in toluene) on the surface to be adhered to the tire rubber. ing.

However, the soft resin-dispersed modified ethylene-vinyl alcohol copolymer has low adhesion and may peel off from the thermoplastic polyurethane layer. In addition, although the flexible resin is dispersed in the modified ethylene-vinyl alcohol copolymer of the flexible resin, the modified ethylene-vinyl alcohol copolymer in the matrix is poor in bending fatigue and is broken during running of the tire. Furthermore, although a rubber paste is applied to the surface to be bonded to the tire rubber, a process different from the normal inner liner manufacturing process is required, resulting in poor productivity.

JP-A-2005-343379 (Patent Document 4) discloses an inner liner designed to have a thickness at a shoulder portion larger than a thickness at a tire crown portion in order to effectively suppress the occurrence of a crack in the inner liner layer. Layers are disclosed. However, when the thickness dimension is increased, the weight is increased, which causes a problem from the viewpoint of reducing the fuel consumption of the tire.

JP-A-2010-013646 (Patent Document 5) proposes to improve adhesion by using a petroleum resin or terpene resin as a tackifier for SIBS which is a thermoplastic elastomer. However, in addition to SIBS, a polyamide-based polymer is blended, and there is a problem that the resistance to flex cracking is lowered.

JP-A-2010-100675 (patent document 6) uses natural rosin, terpene, chroman indene resin, petroleum resin or alkylphenol resin as a tackifier in a blend of SIBS and a sulfur-crosslinkable polymer. It has been proposed to improve the adhesion of carcass ply rubber.

However, in the technology of blending 10 to 300 parts by weight of a sulfur-crosslinkable polymer to 100 parts by weight of SIBS, SIBS is a matrix (sea portion) and sulfur if the amount of the sulfur-crosslinkable polymer is 100 parts by weight or less The crosslinkable polymer forms a domain structure (island portion) and adhesion at the contact interface with the carcass rubber is not improved. When the amount of sulfur-crosslinkable polymer is 100 parts by weight or more, the gas barrier property is lowered except for butyl rubber, and the adhesive strength is lowered in butyl rubber, and the adhesiveness is increased depending on the blended polymer, and the thickness is 600 μm or less There is a problem that the film of can not be produced.

WO 2008/029781 produces tires with strips of film laminates in which a thermoplastic resin and a thermoplastic elastomer are blended. By forming a laminate, gas barrier properties and adhesion can be improved, and bonding between ribbon-like strips is enabled. However, in this technology, the gauge at the unvulcanized green cover of the film laminate is constant, and if the gauge is made thin, there is a possibility that the finished tire after vulcanization at the buttress portion and the like may become thin.

Japanese Patent Laid-Open No. 9-019987 Patent No. 2999188 (Unexamined-Japanese-Patent No. 2000-159936) JP, 2008-024219, A JP, 2005-343379, A JP, 2010-013646, A Unexamined-Japanese-Patent No. 2010-100675 WO 2008/029781

A first object of the present invention is a pneumatic tire provided with an inner liner having excellent air permeability and good adhesion to adjacent rubber, and air having reduced rolling resistance and excellent low temperature durability. It is to provide a tire.

A second object of the present invention is to provide a polymer laminate having good vulcanization adhesion with adjacent rubber and suppressing an increase in rolling resistance, and having excellent air permeability resistance and flex crack growth resistance. It is providing a pneumatic tire.

A third object of the present invention is to provide an inner liner having excellent vulcanization adhesion with adjacent rubber and at the same time suppressing an increase in rolling resistance, and having excellent air permeability resistance and flex crack growth resistance. Another object of the present invention is to provide a pneumatic tire in which the occurrence of air-in is suppressed.

A fourth object of the present invention is to provide an inner liner having excellent vulcanization adhesion with adjacent rubber and at the same time suppressing an increase in rolling resistance, and having excellent air permeability resistance and flex crack growth resistance. Another object of the present invention is to provide a pneumatic tire in which the occurrence of air-in is suppressed.

The present invention is a pneumatic tire comprising an inner liner on the inner side of a carcass ply tire mounted between a pair of bead portions, the inner liner comprising a polymer laminate, the polymer laminate comprising styrene-isobutylene -A first layer comprising a first A polymer composition containing a styrene-triblock copolymer, a first layer having a thickness of 0.05 mm or more and 0.8 mm or less, a styrene-isoprene-styrene triblock copolymer, and a styrene-isobutylene diblock copolymer And a second layer having a thickness of 0.01 mm or more and 0.8 mm or less comprising the second A polymer composition containing at least one of the combination, and at least one of the first A polymer composition and the second A polymer composition is epoxy 0.5% or more by mass of hydrogenated styrene-butadiene-styrene triblock copolymer %, And the second layer is disposed in contact with the rubber layer of the carcass ply, and the inner liner is thicker at the shoulder position Pe than the thickness Gc at the crown center position Pc and has a thickness Ge of 0 .2 mm or more and 1.9 mm or less.

In the pneumatic tire according to the present invention, the epoxidized styrene-butadiene-styrene triblock copolymer has a weight average molecular weight of 10,000 or more and 400,000 or less, and a styrene component content of 10% by mass or more and 30% by mass or less And the epoxy equivalent is preferably 50 or more and 1,000 or less.

The present invention is a pneumatic tire comprising an inner liner on the inner side of a carcass ply tire mounted between a pair of bead portions, the inner liner comprising a polymer laminate, the polymer laminate comprising styrene-isobutylene -A thickness consisting of a first layer comprising a first B polymer composition containing a styrene triblock copolymer and a second layer B containing a styrene-isobutylene diblock copolymer and having a thickness of 0.05 mm or more and 0.6 mm or less At least one of the first B polymer composition and the second B polymer composition containing a second layer having a thickness of 0.01 mm or more and 0.3 mm or less, and 0.1 mass of a tackifier per 100 mass parts of the polymer component And the second layer is disposed in contact with the rubber layer of the carcass ply, and the inner liner is It is thicker Ge shoulder position Pe than the thickness Gc at round the center position Pc.

In the pneumatic tire of the present invention, the tackifier preferably has a weight average molecular weight of 1 × 10 ² or more and 1 × 10 ⁶ or less and a softening point of 50 ° C. or more and 150 ° C. or less.

The present invention is a pneumatic tire having an inner liner on the inner side of a carcass ply tire mounted between a pair of bead portions, the inner liner comprising a styrene-isobutylene-styrene triblock copolymer having a polymer component. A first layer with a thickness of 0.05 mm or more and 0.6 mm or less comprising a first C polymer composition containing 75% by mass to 99.5% by mass and isobutylene-based modified copolymer 0.5% by mass to 25% by mass And a second C polymer composition comprising a polymer component containing 10% by mass to 100% by mass of a styrene-isobutylene block copolymer and 0% by mass to 90% by mass of a styrene-isobutylene-styrene triblock copolymer The isobutylene-based modified copolymer includes an isobu-based modified copolymer including a second layer of 0.01 mm or more and 0.3 mm or less. A random copolymer consisting of a polymer block mainly composed of len and a polymer block mainly composed of an aromatic vinyl compound, wherein at least one block is a random copolymer containing β-pinene and the second layer is a carcass ply rubber The inner liner is disposed in contact with the layer, and the inner liner has a thickness Ge at the shoulder position Pe that is greater than the thickness Gc at the crown center position Pc.

In the pneumatic tire of the present invention, the aromatic vinyl compound of the isobutylene-based modified copolymer is preferably styrene.

The present invention is a pneumatic tire comprising an inner liner on the tire inner side of a carcass ply mounted between a pair of bead portions, the inner liner comprising a styrene-isobutylene-styrene triblock copolymer. A thickness of 0.01 mm or more and 0.3 mm or less, which comprises a first layer having a thickness of 0.05 mm or more and 0.6 mm or less made of a 1D polymer composition, and a second D polymer composition containing a styrene-isobutylene diblock copolymer And the second D polymer composition and at least one of the first D polymer composition and the second D polymer composition is an acid having an unsaturated bond in the styrene block portion of the styrene-isobutylene-styrene triblock copolymer in the polymer component. 10% by weight or more and 99.5% by weight or less of a chloride or acid anhydride-modified SIBS modified copolymer See, and the second layer are arranged in contact with the rubber layer of the carcass ply, an inner liner thickness Ge shoulder position Pe is greater than the thickness Gc at the crown center position Pc.

In the pneumatic tire of the present invention, the SIBS modified copolymer preferably has a styrene component content of 10% by mass to 30% by mass, and a weight average molecular weight of 50,000 to 400,000.

In the pneumatic tire according to the present invention, in the tire meridional section, the normal L is drawn from the ground contact end Te of the tread portion to the tire inner diameter direction with respect to the boundary line between the carcass ply and the inner liner The intersection point of the boundary line between the carcass ply and the inner liner and the tire center line CL is a crown center position Pc, and the distance along the contour of the inner liner from the shoulder position Pe to the crown center position Pc is a shoulder distance Wc In this case, the thick portion of the inner liner is preferably formed in a region having a width of at least 10% of the shoulder distance Wc from the shoulder position Pe to the crown center position Pc side.

In the pneumatic tire of the present invention, the thick portion of the inner liner is preferably formed in a region having a width of at least 50% of the shoulder distance Wc from the shoulder position Pe to the crown center position Pc.

In the pneumatic tire of the present invention, when the distance along the contour of the inner liner from the shoulder position Pe of the inner liner to the tire maximum width position Ps is a side distance Ws, the thick portion of the inner liner is the shoulder position Pe It is preferable to form in the area | region which has a width | variety of at least 20% of the side distance Ws in the largest width position Ps side from this.

In the pneumatic tire of the present invention, the thick portion of the inner liner is preferably formed in a region having a width of 100% or less of the side distance Ws on the tire maximum width position Ps side from the shoulder position Pe.

In the pneumatic tire according to the present invention, the thickness Ge of the shoulder position Pe is preferably 120% or more and 500% or less of the thickness Gc at the crown center position Pc of the inner liner.

In the pneumatic tire according to the present invention, the styrene-isobutylene-styrene triblock copolymer has a styrene component content of 10% by mass to 30% by mass, and a weight average molecular weight of 50,000 to 400,000 preferable.

Regarding the first object of the present invention, according to the present invention, a pneumatic tire provided with an inner liner having good air permeability and good adhesion to adjacent rubber, and reduced rolling resistance, low temperature It is possible to obtain a pneumatic tire excellent in durability.

Regarding the second object of the present invention, according to the present invention, a polymer laminate having good vulcanization adhesion with adjacent rubber and in which the increase in rolling resistance is suppressed, and excellent air permeability and resistance to air It is possible to obtain a pneumatic tire having flex crack growth properties.

Regarding the third object of the present invention, according to the present invention, it has an inner liner having good vulcanization adhesion with the adjacent rubber and suppressing an increase in rolling resistance, and has excellent air permeability and resistance to air. It is possible to obtain a pneumatic tire having flex crack growth properties and in which the occurrence of air-in is suppressed.

Regarding the fourth object of the present invention, according to the present invention, it has an inner liner having good vulcanization adhesion with the adjacent rubber and suppressing an increase in rolling resistance, and has excellent air permeability and resistance to air. It is possible to provide a pneumatic tire having flex crack growth properties and further suppressing the occurrence of air-in.

Furthermore, in the present invention, since the thickness dimension at the shoulder portion of the inner liner is configured to be larger than the thickness dimension at the tire crown portion, the durability of the inner liner at the shoulder portion is improved. For this reason, it is possible to effectively suppress tearing and deformation due to the strength reduction of the inner liner and the reduction of the peeling force, and it is possible to effectively suppress the air leakage.

In addition, since the SIBS is used in the first layer, the SIB is used in the second layer, and the SIBS modified copolymer is used in at least one of the first layer and the second layer, even if the shoulder portion is designed to be thick, butyl Compared to the case where a rubber system is used, the increase in weight of the tire can be suppressed, and the deterioration of rolling resistance can be prevented.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic sectional drawing of the right half of the pneumatic tire in one embodiment of this invention. It is an expansion schematic sectional drawing of the tread part of FIG. It is a schematic sectional drawing of the inner liner of the pneumatic tire in one embodiment of this invention.

First Embodiment
In the first embodiment, the pneumatic tire includes an inner liner on the inner side of a carcass ply tire mounted between a pair of bead portions, the inner liner is made of a polymer laminate, and the polymer laminate is styrene-isobutylene. -A first layer comprising a first A polymer composition containing a styrene-triblock copolymer, a first layer having a thickness of 0.05 mm or more and 0.8 mm or less, a styrene-isoprene-styrene triblock copolymer, and a styrene-isobutylene diblock copolymer And a second layer having a thickness of 0.01 mm or more and 0.8 mm or less comprising the second A polymer composition containing at least one of the combination, and at least one of the first A polymer composition and the second A polymer composition is epoxy 0.5% by mass or more of fluorinated styrene-butadiene-styrene triblock copolymer 4 The second layer is disposed to be in contact with the rubber layer of the carcass ply, and the inner liner is thicker at the shoulder position Pe than at the crown center position Pc and has a thickness Ge It is 0.2 mm or more and 1.9 mm or less.

<Pneumatic tire>
A pneumatic tire according to an embodiment of the present invention will be described based on the drawings. FIG. 1 is a schematic cross-sectional view of the right half of the pneumatic tire, and FIG. 2 is an enlarged schematic cross-sectional view of its tread portion. In FIG. 1, the pneumatic tire 1 has a tread portion 2 and sidewall portions 3 and bead portions 4 so as to form a toroidal shape from both ends of the tread portion. Furthermore, the bead core 5 is embedded in the bead portion 4. Further, a carcass ply 6 is provided from one bead portion 4 to the other bead portion, and both ends are folded around and locked around the bead core 5, and at least two sheets are provided outside the crown portion of the carcass ply 6 And a belt layer 7 consisting of plies.

The belt layer 7 usually crosses two plies made of cords such as steel cords or aramid fibers between the plies so that the cords usually form an angle of 5 to 30 ° with respect to the tire circumferential direction. Arranged as. A topping rubber layer can be provided on the outer sides of both ends of the belt layer to reduce the peeling of both ends of the belt layer. In the carcass ply, organic fiber cords such as polyester, nylon, and aramid are arranged at approximately 90 ° in the tire circumferential direction, and in the region surrounded by the carcass ply and its turn, from the upper end of the bead core 5 to the sidewall direction An extending bead apex 8 is arranged. Further, an inner liner 9 extending from one bead portion 4 to the other bead portion 4 is disposed on the inner side in the tire radial direction of the carcass ply 6.

Here, in the present invention, the position, distance and width in the inner liner 9 are defined as follows.

<Shoulder position Pe>
In the tire meridional section, a normal L is drawn from the ground contact end Te of the tread portion to the tire inner radial direction with respect to the boundary line of the carcass ply and the inner liner, and an intersection point with the boundary line is defined as a shoulder position Pe. Here, the ground contact end Te of the tread portion is defined as a line extending the outer contour of the tread portion and an intersection point extending the outer contour of the shoulder portion.

<Crown center position Pc>
An intersection point between the boundary line of the carcass ply and the inner liner and the tire center line CL is taken as a crown center position Pc.

<Tire maximum width position Ps>
When the tire is filled with the specified internal pressure and the standard rim is fitted, the intersection point of the line parallel to the tire rotation axis passing through the maximum width position Le of the outer contour line and the boundary between the carcass ply and the inner liner is the tire maximum width position Ps Do.

<Shoulder distance Wc>
A distance along the contour of the inner liner from the shoulder position Pe to the crown center position Pc is taken as a shoulder distance Wc.

<Side distance Ws>
A distance along the contour of the inner liner from the shoulder position Pe to the tire maximum width position Ps is taken as a side distance Ws.

<Inner liner thickness>
The thickness of the crown center position Pc of the inner liner is Gc, the thickness at the shoulder position Pe is Ge, and the thickness at the maximum width position Ps is Gs.

The thick portion of the inner liner is preferably formed in a region having a width of at least 10% of the shoulder distance Wc from the shoulder position Pe toward the crown center position Pc. On the other hand, the thick portion is preferably formed in a region having a width of 100% or less of the shoulder distance Wc. Furthermore, the thick portion is preferably formed in a region having a width of at least 50% of the shoulder distance Wc.

The thick portion of the inner liner has a width of at least 20% of the side distance Ws and is formed in a region of 100% or less of the side distance Ws on the side of the maximum width position Ps from the shoulder position Pe. preferable. By setting the thick portion in the range of 20% or more and 100% or less of the side distance Ws from the shoulder position Pe, deformation of the shoulder portion where bending deformation is severed during tire running is suppressed, and stress relaxation in this region is effectively effective. Can be achieved. Furthermore, it is preferable that the thick portion be formed in a range of 20% to 80% of the side distance Ws from the shoulder position Pe.

In the present invention, in the inner liner, the thickness Ge of the shoulder position Pe is larger than the thickness Gc at the crown center position Pc. For this reason, the durability of the inner liner at the shoulder portion is improved, and it is possible to suppress tearing, deformation, and adhesion decrease due to the strength reduction of the inner liner, and as a result, the air leakage of the tire can be effectively suppressed. it can.

The thickness Ge of the shoulder position Pe is 0.2 mm or more and 1.9 mm or less. When Ge is less than 0.2 mm, breakage or deformation is likely to occur during running of the tire. If Ge exceeds 1.9 mm, the effect of reducing the weight of the inner liner can not be obtained sufficiently. The Ge is more preferably 0.3 mm or more and 1.9 mm or less.

The thickness Ge of the shoulder position Pe is preferably 120% or more and 500% or less of the thickness Gc at the crown central position Pc. When the thickness Ge of the shoulder position Pe is less than 120%, suppression of bending deformation and shearing deformation of the shoulder portion is not sufficient, and when it exceeds 500%, the effect of reducing the weight of the inner liner can not be expected sufficiently. The thickness Ge of the shoulder position Pe is more preferably 200% or more and 500% or less of the thickness Gc at the crown central position Pc.

The thickness Ge of the shoulder position Pe is preferably 120% or more and 500% or less of the thickness Gs of the maximum width position Ps.

Preferably, the thick portion is configured to gradually decrease in thickness in the direction of the crown center position Pc and the direction of the maximum width position Ps around the shoulder position Pe. By forming the thick part of the inner liner as described above, the stress can be relieved even if bending deformation and shearing deformation are caused due to repeated deformation in this region during running of the tire, and the inner liner Generation of cracks can be prevented.

<Polymer laminate>
In one embodiment of the present invention, the polymer laminate used for the inner liner is formed of at least two polymer laminates. The first layer is made of the first A polymer composition containing styrene-isobutylene-styrene triblock copolymer (hereinafter also referred to as SIBS), and has a thickness of 0.05 mm or more and 0.8 mm or less. The second layer is composed of a second A polymer composition containing at least one of a styrene-isoprene-styrene triblock copolymer (hereinafter also referred to as SIS) and a styrene-isobutylene diblock copolymer (hereinafter also referred to as SIB). The thickness is 0.01 mm or more and 0.8 mm or less. At least one of the first A polymer composition and the second A polymer composition comprises an epoxidized styrene-butadiene-styrene triblock copolymer.

<First layer>
In one embodiment of the present invention, the first layer consists of the first A polymer composition comprising styrene-isobutylene-styrene triblock copolymer (SIBS). Due to the isobutylene block origin of SIBS, polymer films containing SIBS have excellent resistance to air permeation. Therefore, when the polymer film containing SIBS is used for the inner liner, a pneumatic tire excellent in air permeation resistance can be obtained.

Furthermore, due to complete saturation of molecular structures other than aromatics, SIBS is inhibited from deterioration and hardening and has excellent durability. Therefore, when a polymer film containing SIBS is used for the inner liner, a pneumatic tire excellent in durability can be obtained.

When a pneumatic tire is manufactured by applying a polymer film made of SIBS to the inner liner, the air permeation resistance can be secured. Therefore, it is not necessary to use a high specific gravity halogenated rubber, which has been conventionally used to impart air resistance, such as halogenated butyl rubber, and the amount can be reduced even when used. Thus, the weight of the tire can be reduced, and the fuel efficiency can be improved.

Although the molecular weight of SIBS is not particularly limited, it is preferable that the weight average molecular weight by GPC measurement is 50,000 or more and 400,000 or less from the viewpoint of flowability, molding process, rubber elasticity and the like. If the weight average molecular weight is less than 50,000, the tensile strength and the tensile elongation may be lowered, and if it exceeds 400,000, the extrusion processability may be deteriorated, which is not preferable. From the viewpoint of improving air permeability and durability, SIBS preferably contains 10% by mass to 30% by mass, and more preferably 14% by mass to 23% by mass of the styrene component in SIBS. .

In the copolymer, the degree of polymerization of each block of the SIBS is about 10,000 to 150,000 for isobutylene from the viewpoints of rubber elasticity and handling (the degree of polymerization is less than 10,000 becomes liquid), and styrene And preferably about 5,000 to 30,000.

SIBS can be obtained by a common living cationic polymerization method of vinyl compounds. For example, in JP-A-62-48704 and JP-A-64-62308, living cationic polymerization of isobutylene with another vinyl compound is possible, and by using isobutylene and another compound as the vinyl compound. It is disclosed that polyisobutylene-based block copolymers can be produced.

Since SIBS has no double bond other than aromatic in the molecule, it has higher stability to ultraviolet light than polymers having double bond in the molecule, for example, polybutadiene, and therefore has weatherability It is good. Furthermore, despite having no double bond in the molecule, and despite being a saturated rubber-like polymer, the refractive index (nD) at 20 ° C. of light at a wavelength of 589 nm is given by Polymer Handbook (1989: Wiley) According to (Polymer Handbook, Willy, 1989)), it is 1.506. This is significantly higher than other saturated rubbery polymers, such as ethylene-butene copolymers.

The content of SIBS in the 1A polymer composition is preferably 60% by mass or more and 100% by mass or less. If the content of SIBS is less than 60% by mass, sufficient air permeation resistance can not be obtained. The content of SIBS is more preferably 80% by mass or more and 99.5% by mass or less.

The first polymer composition may further include an epoxidized styrene-butadiene-styrene triblock copolymer (hereinafter also referred to as epoxidized SBS).

Epoxidized SBS is a thermoplastic elastomer in which the hard segment is a polystyrene block and the soft segment is a butadiene block, and the unsaturated double bond portion contained in the butadiene block is epoxidized.

Since epoxidized SBS has a styrene block, it has excellent melt adhesion to the second layer containing SIS and SIB having a styrene block as well. Therefore, when the first layer containing epoxidized SBS and the second layer containing SIS or SIB are disposed adjacent to each other and vulcanized, a polymer laminate in which the first layer and the second layer adhere well is obtained. Can.

The molecular weight of the epoxidized SBS is not particularly limited, but from the viewpoint of rubber elasticity and moldability, the weight average molecular weight by GPC method is preferably 10,000 or more and 400,000 or less. If the weight average molecular weight is less than 10,000, it may be too soft to be stable in size, and if it exceeds 400,000, it may be too hard to be extruded thin, which is not preferable.

The content of the styrene component in the epoxidized SBS is preferably 10% by mass or more and 30% by mass or less from the viewpoints of tackiness, adhesiveness and rubber elasticity.

In the epoxidized SBS, the molar ratio of butadiene unit to styrene unit (butadiene unit / styrene unit) is preferably 90/10 to 70/30. In the epoxidized SBS, the polymerization degree of each block is preferably about 500 to 5,000 for butadiene block and about 50 to 1,500 for styrene block from the viewpoint of rubber elasticity and handling.

The epoxy equivalent of epoxidized SBS is preferably 50 or more and 1,000 or less from the viewpoint of adhesion.

The content of epoxidized SBS in the first A polymer composition can be 0.5% by mass or more and 40% by mass or less. If the content of epoxidized SBS is less than 0.5% by mass, sufficient adhesion can not be obtained. On the other hand, if it exceeds 40% by mass, the productivity is significantly deteriorated due to over-adhesion, which is not preferable. The content of epoxidized SBS is more preferably 5% by mass or more and 30% by mass or less.

The thickness of the first layer including SIBS is 0.05 mm or more and 0.8 mm or less. The thickness of the first layer means the average thickness of the first layer. When the thickness of the first layer is less than 0.05 mm, at the time of vulcanization of a green tire in which the polymer laminate is applied to the inner liner, the first layer is broken by the press pressure, and the air leak phenomenon in the obtained tire May occur. On the other hand, when the thickness of the first layer exceeds 0.8 mm, the weight of the tire increases and the fuel economy performance is reduced. The thickness of the first layer is more preferably 0.05 mm or more and 0.4 mm or less.

The first layer can be obtained by film-forming the first A polymer composition containing SIBS by a conventional method of film-forming a thermoplastic resin such as extrusion, calendar molding, or a thermoplastic elastomer.

<Second layer>
In one embodiment of the present invention, the second layer comprises a second A polymer composition comprising at least one of styrene-isoprene-styrene triblock copolymer (SIS) and styrene-isobutylene diblock copolymer (SIB) Become.

Since the isoprene block of the styrene-isoprene-styrene triblock copolymer (SIS) is a soft segment, the polymer film containing SIS is easy to cure and adhere to the rubber component. Therefore, when a polymer film containing SIS is used for the inner liner, the inner liner is excellent in, for example, the adhesion with the rubber layer of the carcass ply, so that a pneumatic tire excellent in durability can be obtained.

The molecular weight of the SIS is not particularly limited, but in view of rubber elasticity and moldability, it is preferable that the weight average molecular weight by GPC measurement is 100,000 to 290,000. If the weight average molecular weight is less than 100,000, the tensile strength may be lowered, and if it exceeds 290,000, the extrusion processability is unfavorably deteriorated. The content of the styrene component in SIS is preferably 10 to 30% by mass from the viewpoints of tackiness, adhesiveness and rubber elasticity.

The degree of polymerization of each block in the SIS is preferably about 500 to 5,000 for isoprene and about 50 to 1,500 for styrene from the viewpoint of rubber elasticity and handling.

The SIS can be obtained by a general polymerization method of a vinyl compound, and can be obtained, for example, by a living cationic polymerization method.

Since the isobutylene block of the styrene-isobutylene diblock copolymer (SIB) is a soft segment, the polymer film made of SIB is easy to cure and adhere to the rubber component. Therefore, when a polymer film containing SIB is used for the inner liner, the inner liner is excellent in adhesion to the adjacent rubber forming, for example, the carcass and the insulation, so that a pneumatic tire excellent in durability is obtained. be able to.

As SIB, it is preferable to use a linear one from the viewpoint of rubber elasticity and adhesiveness. The molecular weight of SIB is not particularly limited, but from the viewpoint of rubber elasticity and moldability, it is preferable that the weight average molecular weight by GPC measurement is 40,000 to 120,000. If the weight average molecular weight is less than 40,000, the tensile strength may be lowered, and if it exceeds 120,000, the extrusion processability may be deteriorated, which is not preferable.

The content of the styrene component in the SIB is preferably 10 to 35% by mass from the viewpoints of tackiness, adhesiveness and rubber elasticity.

In the present invention, the degree of polymerization of each block in SIB is preferably about 300 to 3,000 for isobutylene and about 10 to 1,500 for styrene from the viewpoint of rubber elasticity and handling.

The SIB can be obtained by a general polymerization method of a vinyl compound, and can be obtained, for example, by a living cationic polymerization method. For example, according to WO 2005/033035, methylcyclohexane, n-butyl chloride and cumyl chloride are added to a stirrer, cooled to -70 ° C, reacted for 2 hours, and then a large amount of methanol is added. A process is disclosed in which the reaction is stopped and vacuum dried at 60 ° C. to obtain SIB.

The second polymer composition may further include epoxidized styrene-butadiene-styrene triblock copolymer (also referred to as epoxidized SBS).

The epoxidized SBS can be the same as the first A polymer composition.
Since epoxidized SBS has a soft segment consisting of butadiene block, it is easy to cure and adhere to the rubber component. Therefore, when the second layer containing epoxidized SBS is placed adjacent to, for example, the rubber layer forming the carcass or insulation and vulcanized, the second layer and the rubber layer can be well adhered. Therefore, when the polymer laminate including the epoxidized SBS layer is used for the inner liner, the adhesion between the polymer laminate and the adjacent rubber layer can be improved.

The thickness T2 of the second layer can be 0.01 mm or more and 0.8 mm or less. The thickness of the second layer means the average thickness of the second layer. If the thickness of the second layer is less than 0.01 mm, the second layer may be broken by the press pressure during vulcanization of a green tire in which the polymer laminate is applied to the inner liner, and the vulcanization adhesion may be reduced. There is. On the other hand, if the thickness of the second layer exceeds 0.8 mm, the weight of the tire increases and the low fuel consumption performance decreases. The thickness of the second layer is more preferably 0.05 mm or more and 0.2 mm or less.

The second layer can be obtained by film-forming the second A polymer composition by a conventional method of film-forming a thermoplastic resin such as extrusion molding, calendar molding, or a thermoplastic elastomer.

<Arrangement of polymer laminate>
The polymer laminate PL is composed of a first layer PL1 and a second layer PL2 as shown in FIG. When the polymer laminate PL is applied to the inner liner of a pneumatic tire, when the second layer PL2 is installed outward in the tire radial direction so as to be in contact with the carcass ply 61, in the tire vulcanization step, the second layer PL2 And the adhesion strength between the two and the carcass 61 can be enhanced. Therefore, the obtained pneumatic tire can have excellent air permeation resistance and durability because the inner liner and the rubber layer of the carcass ply 61 are well adhered.

<Method of producing polymer laminate>
The polymer laminate in one embodiment of the present invention can be produced, for example, by the following method. The first layer and the second layer are produced by extrusion molding, calendar molding or the like. The first layer and the second layer are pasted together to prepare a polymer laminate. The pellets of each of the first A polymer composition and the second A polymer composition can also be produced by lamination extrusion such as lamination extrusion or coextrusion.

<Method of manufacturing pneumatic tire>
The pneumatic tire according to an embodiment of the present invention can be manufactured, for example, by the following method.

A green tire is manufactured by applying the polymer laminate of the present invention to an inner liner portion. The polymer laminate is disposed with the second layer directed radially outward so as to contact the carcass and the insulation. With this arrangement, the second layer and the adjacent rubber layer such as the carcass or insulation can be vulcanized and bonded in the tire vulcanization step. Therefore, in the obtained pneumatic tire, since the inner liner is well adhered to the adjacent rubber layer, it can have excellent air permeation resistance and durability.

With regard to the thickness of the inner liner, the thickness Ge of the shoulder position Pe, the thickness Gc of the crown center position Pc, and the thickness Gs of the maximum width position Ps are the conditions under which the first and second layers are extruded The desired thickness can be obtained by adjusting the extrusion speed and the extrusion rotation speed).

The rubber layer of the carcass ply used in the pneumatic tire according to the present invention comprises generally used rubber components such as natural rubber, polyisoprene, styrene-butadiene rubber, polybutadiene rubber, etc., fillers such as carbon black and silica. It is possible to use a mixture of

Next, the green tire is mounted on a mold and heated while being pressurized by a bladder at 150 to 180 ° C. for 3 to 50 minutes to obtain a vulcanized tire. Next, it is preferable to cool the obtained vulcanized tire at 50 to 120 ° C. for 10 to 300 seconds.

A pneumatic tire uses a polymer laminate for an inner liner. Since SIBS, SIS, SIB and epoxidized SBS constituting the polymer laminate are thermoplastic elastomers, they are softened in the mold when heated to, for example, 150 to 180 ° C. in the process of obtaining a vulcanized tire. Become. The thermoplastic elastomer in the softened state is more reactive than the solid state, and thus fuses with the adjacent member. That is, the inner liner in contact with the outer surface of the expanded bladder is softened by heat and fused to the bladder. If it is attempted to take out the vulcanized tire from the mold in a state in which the inner liner and the outer surface of the bladder are fused, the inner liner peels off from the adjacent insulation or carcass, causing an air-in phenomenon. In addition, the shape of the tire may be deformed.

Therefore, the thermoplastic elastomer used in the inner liner can be solidified by immediately quenching the obtained vulcanized tire at 120 ° C. or less for 10 seconds or more. When the thermoplastic elastomer solidifies, the fusion between the inner liner and the bladder disappears, and the releasability at the time of removing the vulcanized tire from the mold is improved.

The cooling temperature is preferably 50 to 120.degree. If the cooling temperature is lower than 50 ° C., it is necessary to prepare a special cooling medium, which may deteriorate productivity. When the cooling temperature exceeds 120 ° C., the thermoplastic elastomer is not sufficiently cooled, and the inner liner remains fused to the bladder when the mold is opened, which may cause an air-in phenomenon. The cooling temperature is more preferably 70 to 100 ° C.

The cooling time is preferably 10 to 300 seconds. If the cooling time is shorter than 10 seconds, the thermoplastic elastomer is not sufficiently cooled, and the inner liner remains fused to the bladder when the mold is opened, which may cause an air-in phenomenon. If the cooling time exceeds 300 seconds, productivity will deteriorate. The cooling time is more preferably 30 to 180 seconds.

The step of cooling the vulcanized tire is preferably performed by cooling the inside of the bladder. Since the inside of the bladder is hollow, it is possible to introduce a cooling medium adjusted to the cooling temperature into the bladder after the completion of the vulcanization process.

The step of cooling the vulcanized tire can be implemented by installing a cooling structure on the mold together with cooling the inside of the bladder.

As the cooling medium, it is preferable to use one or more selected from the group consisting of air, water vapor, water and oil. Above all, it is preferable to use water which is excellent in cooling efficiency.

Second Embodiment
In Embodiment 2, the pneumatic tire comprises an inner liner on the inner side of a carcass ply tire mounted between a pair of bead portions, the inner liner is made of a polymer laminate, and the polymer laminate is styrene-isobutylene- A thickness comprising a first layer having a thickness of 0.05 mm or more and 0.6 mm or less comprising a first B polymer composition containing a styrene triblock copolymer, and a second B polymer composition comprising a styrene-isobutylene diblock copolymer 0.1 parts by mass of a tackifier per 100 parts by mass of the polymer component, including at least one of the first B polymer composition and the second B polymer composition, including a second layer of 0.01 mm or more and 0.3 mm or less The second layer is disposed to be in contact with the rubber layer of the carcass ply, and the inner liner It is thicker Ge shoulder position Pe than the thickness Gc at the crown center position Pc.

<Pneumatic tire>
The pneumatic tire according to the second embodiment can basically have the same structure as that of the first embodiment.

In the second embodiment, the thick portion of the inner liner is preferably formed in the range of 10% to 60% of the shoulder distance Wc.

The thickness Ge of the shoulder position Pe is preferably 0.2 mm or more and 1.9 mm or less. When Ge is less than 0.2 mm, breakage or deformation is likely to occur during running of the tire. If Ge exceeds 1.9 mm, the effect of reducing the weight of the inner liner can not be obtained sufficiently. The Ge is more preferably 0.3 mm or more and 1.9 mm or less.

<Polymer laminate>
In Embodiment 2, the polymer laminate used for the inner liner is formed of at least two polymer laminates. The first layer is made of a first B polymer composition containing styrene-isobutylene-styrene triblock copolymer (hereinafter also referred to as SIBS), and has a thickness of 0.05 mm or more and 0.6 mm or less. The second layer is composed of a second B polymer composition containing a styrene-isobutylene diblock copolymer (hereinafter also referred to as SIB), and has a thickness of 0.01 mm or more and 0.3 mm or less. At least one of the first B polymer composition and the second B polymer composition comprises a tackifier.

<First layer>
In one embodiment of the present invention, the first layer consists of a first B polymer composition comprising styrene-isobutylene-styrene triblock copolymer (SIBS).

The same SIBS as in Embodiment 1 can be used.
The content of SIBS in the first B polymer composition is preferably 60% by mass or more and 100% by mass or less. If the content of SIBS is less than 60% by mass, sufficient air permeation resistance can not be obtained. The content of SIBS is more preferably 80% by mass or more and 99.5% by mass or less.

The first B polymer composition may further comprise a tackifier.
The tackifier refers to a compounding agent for promoting the tackiness of the polymer composition, and, for example, the following can be used.

Typically, there are C9 petroleum resin and C5 petroleum resin. Here, C9 petroleum resin is pyrolyzing naphtha to obtain useful compounds such as ethylene, propylene and butadiene, but the remaining C5-C9 fraction (mainly C9 fraction) from which they are removed is mixed and mixed It is an aromatic petroleum resin obtained by polymerizing as it is. For example, Alcon P70, P90, P100, P125, P140, M90, M100, M115, and M135 (all manufactured by Arakawa Chemical Industries, Ltd., softening point 70 to 145 ° C.), and Imarb S100 and S110 as trade names. P100, P125, P140 (all manufactured by Idemitsu Petrochemical Co., Ltd., aromatic copolymer hydrogenated petroleum resin, softening point 100 to 140 ° C., weight average molecular weight 700 to 900, bromine number 2.0 to 6.0 g / 100 g) and Petcoal XL (manufactured by Tosoh Corporation).

With C5 petroleum resin, naphtha is pyrolyzed to obtain useful compounds such as ethylene, propylene and butadiene, but the remaining C4-C5 fraction (mainly C5 fraction) from which they are removed is mixed It is the aliphatic petroleum resin obtained by polymerizing as it is. As trade name, Hilets G100 (made by Mitsui Petrochemicals Co., Ltd., softening point is 100 ° C), Malkaletz T100AS (made by Maruzen Sekiyu Co., Ltd., softening point 100 ° C), further Escorez 1102 (made by Tonex Co., Ltd., softened There is a point of 110 ° C).

Terpene resin is, for example, trade name: YS resin PX800N, PX1000, PX1150, PX1250, PXN1150N, Clearon P85, P105, P115, P125, P135, P150, M105, M115, K100 (all manufactured by Yasuhara Chemical Co., Ltd., softened) The point is 75-160 ° C.).

The aromatic-modified terpene resin is, for example, commercially available as YS resin TO85, TO105, TO115, or TO125 (all are manufactured by Yasuhara Chemical Co., Ltd., and have a softening point of 75 to 165 ° C.).

Terpene phenol resin is, for example, commercially available as Tamanor 803L, 901 (Arakawa Chemical Industries, Ltd., softening point 120 ° C. to 160 ° C.), YS polystar U115, U130, T80, T100, T100, T115, T145, T160 (any one) The softening point is also 75-165 ° C., manufactured by Yasuhara Chemical Co., Ltd.

The coumarone resin is, for example, coumarone resin having a softening point of 90 ° C. (manufactured by Kobe Oil Chemical Industry Co., Ltd.). For example, as a trade name, coumarone-indene oil is 15E (manufactured by Kobe Oil Chemical Industry Co., Ltd .; pour point 15 ° C.).

Rosin ester is, for example, commercially available as ester gum AAL, A, AAV, 105, AT, H, HP, HD (all by Arakawa Chemical Industries Co., Ltd., softening point 68 ° C. to 110 ° C.), and Haliester TF , S, C, DS70L, DS90, DS130 (all are Harima Chemicals Co., Ltd., softening point: 68 ° C. to 138 ° C.). As hydrogenated rosin esters, for example, Super Ester A 75, A 100, A 115, A 125 (all manufactured by Arakawa Chemical Industries, Ltd., softening point 70 ° C. to 130 ° C.) are available as trade names.

The alkylphenol resin has, for example, TAMANOR 510 (manufactured by Arakawa Chemical Industries, Ltd., softening point 75 ° C. to 95 ° C.) as a trade name. As DCPD, Escholez 5300 (manufactured by Tonex Co., Ltd., softening point 105 ° C.) is available as a trade name.

The tackifier can enhance the adhesion without causing the fully hydrogenated petroleum resin of C9 petroleum resin to be compatible with SIBS and without lowering the gas barrier property. It also has the effect of lowering the viscosity, and can be advantageously used for film extrusion.

The tackifier preferably has a weight average molecular weight of 1 × 10 ² or more and 1 × 10 ⁶ or less. If the weight average molecular weight is less than 1 × 10 ² , the viscosity may be reduced, and the formability of the sheet may be disadvantageous. On the other hand, when the weight average molecular weight exceeds 1 × 10 ⁶ , there is a possibility that the adhesion of the polymer sheet with tackiness may be insufficient. Furthermore, the tackifier preferably has a softening point of 50 ° C. or more and 150 ° C. or less.

The tackifier is blended in a range of 0.1 parts by mass to 100 parts by mass, preferably 1 part by mass to 50 parts by mass, with respect to 100 parts by mass of the polymer component of the 1B polymer composition. When the tackifier is less than 0.1 parts by mass, the vulcanization adhesion with the second layer is not sufficient, while when it exceeds 100 parts by mass, the tackiness becomes too high, and the processability and productivity are increased. The gas barrier property is further reduced.

The thickness of the first layer is 0.05 mm or more and 0.6 mm or less. The thickness of the first layer means the average thickness of the first layer. When the thickness of the first layer is less than 0.05 mm, at the time of vulcanization of a green tire in which the polymer laminate is applied to the inner liner, the first layer is broken by the press pressure, and the air leak phenomenon in the obtained tire May occur. On the other hand, when the thickness of the first layer exceeds 0.6 mm, the weight of the tire increases and the fuel economy performance is reduced. The thickness of the first layer is more preferably 0.05 mm or more and 0.4 mm or less.

The first layer can be obtained by film-forming the 1B polymer composition containing SIBS by a conventional method of film-forming a thermoplastic resin such as extrusion, calendering, or a thermoplastic elastomer.

<Second layer>
In one embodiment of the present invention, the second layer consists of a second B polymer composition comprising styrene-isobutylene diblock copolymer (SIB).

The same SIB as that of the first embodiment can be used.
The second B polymer composition may further include epoxidized styrene-butadiene-styrene triblock copolymer (also referred to as epoxidized SBS).

The second B polymer composition may further comprise a tackifier. The tackifier may be the same as in the first layer.

The tackifier is blended in a range of 0.1 parts by mass to 100 parts by mass, preferably 1 part by mass to 50 parts by mass, with respect to 100 parts by mass of the polymer component of the second B polymer composition. When the tackifier is less than 0.1 part by mass, the vulcanization adhesion with the first layer is not sufficient, while when it exceeds 100 parts by mass, the tackiness becomes too high, resulting in processability and productivity. The gas barrier property is further reduced.

The thickness of the second layer can be 0.01 mm or more and 0.3 mm or less. The thickness of the second layer means the average thickness of the second layer. If the thickness of the second layer is less than 0.01 mm, the second layer may be broken by the press pressure during vulcanization of a green tire in which the polymer laminate is applied to the inner liner, and the vulcanization adhesion may be reduced. There is. On the other hand, if the thickness of the second layer exceeds 0.3 mm, the weight of the tire increases and the fuel economy performance decreases. The thickness of the second layer is more preferably 0.05 mm or more and 0.2 mm or less.

The second layer can be obtained by film-forming the second B polymer composition by a conventional method of film-forming a thermoplastic resin such as extrusion molding, calendar molding, or a thermoplastic elastomer.
<Arrangement of polymer laminate>
The polymer laminate PL is composed of a first layer PL1 and a second layer PL2 as shown in FIG. When the polymer laminate PL is applied to the inner liner of a pneumatic tire, when the second layer PL2 is installed outward in the tire radial direction so as to be in contact with the carcass ply 61, in the tire vulcanization step, the second layer PL2 And the adhesion strength between the two and the carcass 61 can be enhanced. Therefore, the obtained pneumatic tire can have excellent air permeation resistance and durability because the inner liner and the rubber layer of the carcass ply 61 are well adhered.

<Method of producing polymer laminate>
The polymer laminate in Embodiment 2 can be produced using the same production method as in Embodiment 1.

<Method of manufacturing pneumatic tire>
The pneumatic tire according to the second embodiment can be manufactured using the same manufacturing method as that of the first embodiment.

Third Embodiment
In the third embodiment, the pneumatic tire includes an inner liner on the tire inner side of a carcass ply mounted between a pair of bead portions, and the inner liner is a styrene-isobutylene-styrene triblock copolymer having a polymer component. A first layer with a thickness of 0.05 mm or more and 0.6 mm or less comprising a first C polymer composition containing 75% by mass to 99.5% by mass and isobutylene-based modified copolymer 0.5% by mass to 25% by mass And a second C polymer composition comprising a polymer component containing 10% by mass to 100% by mass of a styrene-isobutylene block copolymer and 0% by mass to 90% by mass of a styrene-isobutylene-styrene triblock copolymer The isobutylene-based modified copolymer comprises a second layer of 0.01 mm or more and 0.3 mm or less, and A rubber copolymer composed mainly of butylene and a polymer block composed mainly of an aromatic vinyl compound, wherein at least one block is a random copolymer including β-pinene, and the second layer is a carcass ply rubber The inner liner is disposed in contact with the layer, and the inner liner has a thickness Ge at the shoulder position Pe that is greater than the thickness Gc at the crown center position Pc.
<Pneumatic tire>
The pneumatic tire according to the third embodiment can basically have the same structure as that of the first embodiment.

In the third embodiment, the thick portion of the inner liner is preferably formed in the range of 10% to 60% of the shoulder distance Wc from the shoulder position Pe to the crown center position Pc side.
<Inner liner>
In the third embodiment, the inner liner of the pneumatic tire includes a first layer and a second layer.
(First layer)
In the first layer, the polymer component is 75% by mass to 99.5% by mass of styrene-isobutylene-styrene triblock copolymer (hereinafter also referred to as SIBS) and 0.5% by mass to 25% by mass of isobutylene-based modified copolymer % C or less and having a thickness of 0.05 mm or more and 0.6 mm or less.

The same SIBS as in Embodiment 1 can be used.
The content of SIBS in the first C polymer composition is preferably 75% by mass or more and 99.5% by mass or less in the polymer component. If the content of SIBS is less than 75% by mass, the air permeation resistance may not be sufficiently obtained. On the other hand, when the content of SIBS exceeds 99.5% by mass, the vulcanization adhesion may be reduced. The content of SIBS is more preferably 80% by mass or more and 95% by mass or less.
(Isobutylene-based modified copolymer)
In the present specification, the isobutylene-based modified copolymer is an isobutylene-based modified copolymer composed of a polymer block mainly composed of isobutylene and a polymer block mainly composed of an aromatic vinyl compound, One block is a random copolymer containing β-pinene.

Here, the isobutylene-based modified copolymer is typically a styrene-isobutylene-styrene block copolymer (SIBS), a styrene-isoprene-styrene block copolymer (SIS) or a styrene-isobutylene block copolymer (SIB) Copolymers in which β-pinene is contained in the styrene block of

The polymer block mainly composed of isobutylene is a polymer block composed of 80% by mass or more of units whose soft segment is derived from isobutylene. The polymer block can be produced using, as a monomer component, aliphatic olefins, dienes, vinyl ethers, silanes, vinyl carbazole, acenaphthylene and the like.

On the other hand, the polymer block mainly composed of an aromatic vinyl compound is a polymer block in which the hard segment is composed of 80% by mass or more of units derived from the aromatic vinyl compound.

Examples of the aromatic vinyl compounds include styrene, methylstyrene, α-methylstyrene, β-methylstyrene, 2,6-dimethylstyrene, 2,4-dimethylstyrene, α-methyl-o-methylstyrene and α-methyl- m-methylstyrene, α-methyl-p-methylstyrene, β-methyl-o-methylstyrene, β-methyl-m-methylstyrene, β-methyl-p-methylstyrene, 2,4,6-trimethylstyrene, α-Methyl-2,6-dimethylstyrene, α-methyl-2,4-dimethylstyrene, β-methyl-2,6-dimethylstyrene, β-methyl-2,4-dimethylstyrene, chlorostyrene, 2,6 -Dichlorostyrene, 2,4-dichlorostyrene, α-chloro-o-chlorostyrene, α-chloro-m-chlorostyrene, α-chloro-p-k Rosystyrene, β-chloro-o-chlorostyrene, β-chloro-m-chlorostyrene, β-chloro-p-chlorostyrene, 2,4,6-trichlorostyrene, α-chloro-2,6-dichlorostyrene, α -Chloro-2,4-dichlorostyrene, β-chloro-2,6-dichlorostyrene, β-chloro-2,4-dichlorostyrene, t-butylstyrene, methoxystyrene, chloromethylstyrene, bromomethylstyrene etc. Be done. Particularly, from the viewpoint of cost, styrene and α-methylstyrene are preferable.

The isobutylene-based modified copolymer is a random copolymer of β-pinene and at least one of a polymer block mainly composed of isobutylene and a polymer block mainly composed of an aromatic vinyl compound. From the viewpoint of low temperature properties, it is preferable that β-pinene is copolymerized with a polymer block mainly composed of an aromatic vinyl compound.

On the other hand, from the viewpoint of adhesiveness, it is preferable that β-pinene is copolymerized with a polymer block mainly composed of isobutylene. In this case, the content of β-pinene is preferably 0.5% by mass or more and 25% by mass or less, and more preferably 2% by mass or more and 25% by mass or less of the isobutylene-based modified copolymer. When the content of β-pinene is less than 0.5% by mass, the adhesion is not sufficient, and when it exceeds 25% by mass, the composition becomes brittle and rubber elasticity tends to decrease.

There is no particular limitation on the structure of the isobutylene-based modified copolymer, and any block copolymer having a linear, branched or star molecular chain structure, triblock copolymer, multiblock copolymer, etc. It is selectable. From the point of balance of physical properties and molding processability, a polymer block mainly composed of isobutylene (hereinafter also referred to as block (A)) and a polymer block mainly composed of an aromatic vinyl compound (hereinafter also referred to as block (B) What has a structure of a diblock copolymer ((A)-(B)) and a triblock copolymer ((B)-(A)-(B)) can be employ | adopted. These can be used alone or in combination of two or more in order to obtain desired physical properties and molding processability.

The molecular weight of the isobutylene-based modified copolymer is preferably 30,000 or more and 300,000 or less in terms of weight average molecular weight by GPC measurement, from the viewpoint of flowability, moldability, rubber elasticity, etc., 30,000 or more It is particularly preferable that it is 150,000 or less. When the weight average molecular weight is less than 30,000, mechanical physical properties tend not to be sufficiently expressed, while when it exceeds 300,000, the flowability and processability tend to be deteriorated. Furthermore, it is preferable that the value (weight average molecular weight / number average molecular weight) of the molecular weight distribution of the isobutylene-based modified copolymer is 1.3 or less from the viewpoint of processing stability.

The content of the isobutylene-based modified copolymer in the first C polymer composition is preferably 0.5% by mass to 25% by mass in the polymer component, and more preferably 5% by mass to 20% by mass. If the content of the isobutylene-based modified copolymer is less than 0.5% by mass, the vulcanization adhesion with the second layer may be reduced.

The method for producing the isobutylene-based modified copolymer is disclosed, for example, in JP-A-2010-195969. For example, it can be produced by polymerizing monomer components in the presence of a polymerization initiator represented by the following general formula (I).

(CR ¹ R ² X) n R ³ (1)
(Wherein X is a halogen atom, a substituent selected from an alkoxy group having 1 to 6 carbon atoms, or an acyloxy group, R ¹ and R ² each represent a hydrogen atom or a monovalent hydrocarbon group having 1 to 6 carbon atoms, R ¹ R ² may be the same or different, R ³ is a monovalent or polyvalent aromatic hydrocarbon group or a monovalent or polyvalent aliphatic hydrocarbon group, and n is a natural number of 1 to 6 .)
The compound represented by the above general formula (1) is to be an initiator and forms a carbon cation in the presence of a Lewis acid or the like to be a starting point of cationic polymerization. As an example of the compound of the above general formula (1), bis (1-chloro-1-methylethyl) benzene [C ₆ H ₄ (C (CH ₃ ) ₂ Cl) ₂ ], tris (1-chloro-1-methyl) ethyl) benzene _{_{[(ClC (CH 3) 2}} ) 3 C 6 H 3] can be exemplified.

When producing the isobutylene-based modified copolymer, a Lewis acid catalyst can also be made to coexist. The Lewis acid can be used for cationic polymerization, for example, metal halides such as TiCl ₄ , TiBr ₄ , BCl ₃ , BF ₃ , BF ₃ · OEt ₂ , ZnBr ₂ , AlCl _{3 and the} like; Et ₂ AlCl, EtAlCl ₂ etc. The following organometallic halides can be used. The Lewis acid can be used at 0.1 to 100 molar equivalents relative to the compound represented by the general formula (1).

Moreover, an electron donor component can also be made to coexist in the case of manufacture of an isobutylene type modified copolymer. The electron donor component is, for example, pyridines, amines, amides or sulfoxides.

The polymerization of the isobutylene-based modified copolymer can be carried out in an organic solvent, and as the organic solvent, one that does not inhibit cationic polymerization can be used. For example, halogenated hydrocarbons such as methyl chloride, dichloromethane, chloroform, ethyl chloride and dichloroethane, alkylbenzenes such as benzene, toluene, xylene and ethylbenzene, linear aliphatic carbonization such as ethane, propane, butane, pentane, hexane and heptane Hydrogens, branched aliphatic hydrocarbons such as 2-methylpropane and 2-methylbutane, and cyclic aliphatic hydrocarbons such as cyclohexane, methylcyclohexane and ethylcyclohexane can be used.

The amount of the organic solvent is adjusted so that the concentration of the copolymer becomes 5 to 40% by mass from the viewpoint of adjusting the viscosity of the copolymer solution to be produced and the heat dissipation. The copolymerization reaction is preferably in the range of −20 ° C. to −70 ° C.
(Other ingredients)
The first C polymer composition used for the first layer of the inner liner can contain a crosslinking agent and a coagent. As the crosslinking agent, sulfur, tetramethylthiuram disulfide, 4,4-dithiobismorpholine, organic peroxide, phenolformaldehyde resin, halomethylphenol can be used.

Examples of crosslinking assistants include metal oxides such as sulfenamide, benzothiazole, guanidine, dithiocarbamic acid and zinc oxide, fatty acids such as stearic acid, nitrogen-containing compounds, triallyl isocyanurate, ethylene glycol dimethacrylate and trimethylolpropane methacrylate It can be used. The compounding amounts of the crosslinking agent and the crosslinking aid are each 0.3 part by mass or more and 6 parts by mass or less with respect to 100 parts by mass of the elastomer component.

The first C polymer composition may further contain fillers, anti-aging agents, softeners, processing aids and the like. As the filler, carbon black, wet silica, dry silica, calcium carbonate, kaolin, talc, clay and the like can be used. Anti-aging agents include antioxidants, ultraviolet light absorbers, light stabilizers. As the softener, paraffin oil, naphthene oil, aroma oil, rapeseed oil, dioctyl phthalate and the like can be used. As the processing aid, higher fatty acids, fatty acid esters, fatty acid metal salts, fatty acid amides, paraffin waxes, fatty alcohols, fluorine / silicone resins and the like can be used.
(Thickness of first layer)
The thickness of the first layer can be 0.05 mm or more and 0.6 mm or less. Here, the thickness of the first layer means the average thickness of the first layer. If the thickness of the first layer is less than 0.05 mm, the first layer may be broken by the press pressure during vulcanization of the green tire on which the inner liner is disposed, and the air leak may occur in the obtained tire. is there. On the other hand, when the thickness of the first layer exceeds 0.6 mm, the weight of the tire increases and the fuel economy performance is reduced. The thickness of the first layer is more preferably 0.05 mm or more and 0.4 mm or less.

The first layer can be obtained by film-forming the first C polymer composition by a conventional method of film-forming a thermoplastic resin such as extrusion molding, calendar molding, or a thermoplastic elastomer.
(2nd layer)
In the second layer, the polymer component is 10% by mass or more and 100% by mass or less of styrene-isobutylene block copolymer (hereinafter also referred to as SIB) and 0 mass of styrene-isobutylene-styrene triblock copolymer (hereinafter also referred to as SIBS) And a thickness of 0.01 mm or more and 0.3 mm or less.
(Styrene-isobutylene block copolymer)
Since the isobutylene block of the styrene-isobutylene diblock copolymer (SIB) is a soft segment, the polymer film containing SIB is easy to cure and adhere to the rubber component. Therefore, when a polymer film containing SIB is used for the inner liner, the inner liner is excellent in adhesion to the adjacent rubber forming, for example, the carcass and the insulation, so that a pneumatic tire excellent in durability is obtained. be able to.

The same SIB as that of the first embodiment can be used.
The content of SIB in the second C polymer composition is 10% by mass or more and 100% by mass or less in the polymer component. If the content of SIB is less than 10% by mass, the vulcanization adhesion may be reduced. The content of SIB is more preferably 10% by mass or more and 30% by mass or less.
(SIBS)
The same SIBS as that of the first C polymer composition can be used in the second C polymer composition.
(Other ingredients)
Similar to the first C polymer composition, the second C polymer composition may include a crosslinking agent, a coagent, a filler, an antiaging agent, a softener, a processing aid, and the like.
(Thickness of second layer)
The thickness of the second layer can be 0.01 mm or more and 0.3 mm or less. Here, the thickness of the second layer means the average thickness of the second layer. When the thickness of the second layer is less than 0.01 mm, the second layer may be broken by the press pressure at the time of vulcanization of the green tire on which the inner liner is disposed, and the vulcanization adhesion may be reduced. On the other hand, if the thickness of the second layer exceeds 0.3 mm, the weight of the tire increases and the fuel economy performance decreases. The thickness of the second layer is more preferably 0.05 mm or more and 0.2 mm or less.

The second layer can be obtained by film-forming the second C polymer composition by a conventional method of film-forming a thermoplastic resin such as extrusion molding, calendar molding, or a thermoplastic elastomer.
<Placement of inner liner>
Inner liner PL is comprised from 1st layer PL1 and 2nd layer PL2, as shown in FIG. In the case of applying the inner liner PL to a pneumatic tire, when the second layer PL2 is installed outward in the tire radial direction such that the second layer PL2 contacts the carcass ply 61, the second layer PL2 and the carcass 61 are Bond strength can be increased. Therefore, the obtained pneumatic tire can have excellent air permeation resistance and durability because the inner liner and the rubber layer of the carcass ply 61 are well adhered.

<Method of manufacturing inner liner>
The inner liner can be manufactured, for example, by the following method. The first layer and the second layer are produced by extrusion molding, calendar molding or the like. The first layer and the second layer are laminated to produce an inner liner. The pellets of each of the first C polymer composition and the second C polymer composition can also be produced by lamination extrusion such as lamination extrusion or coextrusion.

<Method of manufacturing pneumatic tire>
The pneumatic tire according to the third embodiment can be manufactured using the same manufacturing method as that of the first embodiment.

Fourth Embodiment
In the fourth embodiment, the pneumatic tire includes an inner liner on the tire inner side of a carcass ply mounted between a pair of bead portions, and the inner liner includes a styrene-isobutylene-styrene triblock copolymer. The first layer having a thickness of 0.05 mm to 0.6 mm made of the polymer composition, and the second layer D having a styrene-isobutylene diblock copolymer having a thickness of 0.01 mm to 0.3 mm In the polymer component, at least one of the first D polymer composition and the second D polymer composition comprises an acidation having an unsaturated bond in the styrene block portion of the styrene-isobutylene-styrene triblock copolymer in the polymer component. 10% by weight or more and 99.5% by weight or more of SIBS modified copolymer modified with Wherein, and a second layer arranged in contact with the rubber layer of the carcass ply, an inner liner thickness Ge shoulder position Pe is greater than the thickness Gc at the crown center position Pc.
<Pneumatic tire>
The pneumatic tire according to the fourth embodiment can basically have the same structure as that of the first embodiment.

In the fourth embodiment, the thick portion of the inner liner is preferably formed in the range of 10% to 60% of the shoulder distance Wc from the shoulder position Pe to the crown center position Pc side.

The thickness Ge of the shoulder position Pe is preferably 0.2 mm or more and 1.9 mm or less. When Ge is less than 0.2 mm, breakage or deformation is likely to occur during running of the tire. If Ge exceeds 1.9 mm, the effect of reducing the weight of the inner liner can not be obtained sufficiently. The Ge is more preferably 0.3 mm or more and 1.9 mm or less.
<Inner liner>
In one embodiment of the present invention, the inner liner comprises a first layer and a second layer.
(First layer)
The first layer is made of a first D polymer composition containing styrene-isobutylene-styrene triblock copolymer (hereinafter also referred to as SIBS), and has a thickness of 0.05 mm or more and 0.6 mm or less.

The same SIBS as in Embodiment 1 can be used.
(SIBS modified copolymer)
The first D polymer composition can include an SIBS modified copolymer in which a styrene block portion of a styrene-isobutylene-styrene block copolymer is modified with an acid chloride or an acid anhydride having an unsaturated bond.

The SIBS modified copolymer is one in which the styrene block portion is modified with an acid chloride or an acid anhydride having an unsaturated bond, and contains a chemical structure of the following formula (1) in a molecular chain.

In Formula (1), R ₁ is a monovalent organic group having a functional group.
Examples of the acid chloride having an unsaturated bond used for modification include methacrylic acid chloride, methacrylic acid bromide, methacrylic acid iodide, acrylic acid chloride, acrylic acid bromide, acrylic acid iodide, crotonyl chloride and crotonyl acid bromide. . In particular, methacrylic acid chloride and acrylic acid chloride are preferable.

Moreover, although an acetic anhydride, a maleic anhydride, a phthalic anhydride etc. are illustrated with an acid anhydride, an acetic anhydride is especially preferable. These compounds can also be used in combination of two or more. Since the unsaturated group is introduced into SIBS by such modification, crosslinking using a crosslinking agent can be enabled.

The content of acid chloride and acid anhydride having unsaturated bonds in the SIBS modified copolymer is 1% by weight or more, preferably 5% by weight or more, and 30% by weight or less.

A conventional method can be used for crosslinking the SIBS modified copolymer, and for example, thermal crosslinking by heating and crosslinking by a crosslinking agent can be performed. Here, organic peroxides such as dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di- (tert-butylperoxy) hexane, etc. can be used as a crosslinking agent. . The compounding amount of the organic peroxide is preferably in the range of 0.1 to 3.0 parts by mass with respect to 100 parts by mass of the thermoplastic elastomer component.

The first D polymer composition is a multifunctional vinyl monomer such as divinylbenzene, triallyl cyanurate, or a multifunctional methacrylate monomer such as ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, Trimethylolpropane trimethacrylate and allyl methacrylate can be used in combination as a crosslinking agent. In this case, the improvement of the flex crack characteristics of the composition after crosslinking can be expected.

The SIBS modified copolymer is derived from an isobutylene block, and the film containing the SIBS modified copolymer has excellent air permeation resistance. In addition, SIBS-modified copolymers can be thermally crosslinked and crosslinked by a crosslinking agent because unsaturated groups are introduced into SIBS, and they have bending crack characteristics and basic properties such as tensile strength, elongation at break and permanent strain. The air permeation resistance is improved and the properties as an inner liner are improved.

When a pneumatic tire is manufactured by applying a polymer film made of a polymer composition containing a SIBS modified copolymer to an inner liner, air permeation resistance can be secured. Therefore, it is not necessary to use a high specific gravity halogenated rubber, which has been conventionally used to impart air resistance, such as halogenated butyl rubber, and the amount can be reduced even when used. Thus, the weight of the tire can be reduced, and the fuel efficiency can be improved.

The blending amount of the SIBS modified copolymer is preferably 10% by mass to 99.5% by mass in the polymer component of the first D polymer composition, and more preferably 30% by mass to 99.5% by mass. If the compounding amount of the SIBS modified copolymer is less than 10% by mass of the polymer component, there is a possibility that the vulcanization adhesion with the second layer is not sufficient.

In one embodiment of the present invention, at least one of the first D polymer composition and the second D polymer composition described later contains the SIBS modified copolymer. In this case, the compounding amount of the SIBS modified copolymer is 10% by mass to 99.5% by mass in the polymer component of the first D polymer composition, or 10% by mass to 99.5% in the polymer component of the second D polymer composition. It is less than mass.

The molecular weight of the SIBS modified copolymer is not particularly limited, but it is preferable that the weight average molecular weight by GPC measurement is 50,000 or more and 400,000 or less, from the viewpoint of flowability, molding process, rubber elasticity and the like. If the weight average molecular weight is less than 50,000, the tensile strength and the tensile elongation may be lowered, and if it exceeds 400,000, the extrusion processability may be deteriorated, which is not preferable. The content of the styrene component in SIBS is preferably 10% by mass or more and 30% by mass or less, and more preferably 14% by mass or more and 23% by mass or less, from the viewpoint of making the air permeation resistance and durability better. Is preferred.

For example, the following method can be adopted for the production of the SIBS modified copolymer. After placing the styrene-isobutylene-styrene triblock copolymer in a separable flask, the inside of the polymerization vessel is replaced with nitrogen. Thereafter, organic solvents (eg, n-hexane and butyl chloride) dried with molecular sieves are added, and further, methacrylic acid chloride is added. Finally, the solution is reacted while adding aluminum trichloride while stirring. After a predetermined time from the start of the reaction, a predetermined amount of water is added to the reaction solution and stirred to terminate the reaction. The reaction solution is washed with a large amount of water several times and further slowly dropped into a large amount of a mixed solvent of methanol and acetone to precipitate a polymer, and the resulting polymer is dried under vacuum. The method of producing the SIBS modified copolymer is disclosed, for example, in Japanese Patent No. 4551005.
(Polymer component)
The 1st D polymer composition can contain polymers other than SIBS and SIBS modified copolymer as a polymer component. For example, thermoplastic elastomers, in particular styrenic thermoplastic elastomers, are preferably used. Here, the styrene-based thermoplastic elastomer refers to a copolymer containing a styrene block as a hard segment. For example, styrene-isoprene-styrene block copolymer (SIS), styrene-isobutylene diblock copolymer (SIB), styrene-butadiene-styrene block copolymer (SBS), styrene-ethylene-butene-styrene block copolymer Combination (SEBS), styrene-ethylene-propylene-styrene block copolymer (SEPS), styrene-ethylene-ethylene-propylene-styrene block copolymer (SEEPS), styrene-butadiene-butylene-styrene block copolymer (SBBS) Can be mentioned.

In addition, the styrenic thermoplastic elastomer may have an epoxy group in its molecular structure. For example, Epofriend A 1020 (made by Daicel Chemical Industries, Ltd., weight average molecular weight is 100,000, epoxy equivalent is 500) Epoxy modified styrene-butadiene-styrene copolymer (epoxidized SBS) can be used.

The first D polymer composition can be mixed with a rubber component as a polymer component. The rubber component preferably contains at least one selected from the group consisting of natural rubber, isoprene rubber, chloroprene rubber and butyl rubber. The blending amount of the rubber component is preferably in the range of 5 to 20 parts by mass with respect to 100 parts by mass of the thermoplastic elastomer component.
(Other ingredients)
The first D polymer composition used for the first layer of the inner liner can contain a crosslinking agent and a coagent. As the crosslinking agent, sulfur, tetramethylthiuram disulfide, 4,4-dithiobismorpholine, organic peroxide, phenolformaldehyde resin, halomethylphenol can be used.

The first D polymer composition may further contain a filler, an antiaging agent, a softener, a processing aid, a vulcanization accelerator, an antiblocking agent, and the like. As the filler, carbon black, wet silica, dry silica, calcium carbonate, kaolin, talc, clay and the like can be used. Anti-aging agents include antioxidants, ultraviolet light absorbers, light stabilizers. As the softener, paraffin oil, naphthene oil, aroma oil, rapeseed oil, dioctyl phthalate, stearic acid and the like can be used. As the processing aid, higher fatty acids, fatty acid esters, fatty acid metal salts, fatty acid amides, paraffin waxes, fatty alcohols, fluorine / silicone resins and the like can be used.
(Thickness of first layer)
The thickness of the first layer can be 0.05 mm or more and 0.6 mm or less. Here, the thickness of the first layer means the average thickness of the first layer. If the thickness of the first layer is less than 0.05 mm, the first layer may be broken by the press pressure during vulcanization of the green tire on which the inner liner is disposed, and the air leak may occur in the obtained tire. is there. On the other hand, when the thickness of the first layer exceeds 0.6 mm, the weight of the tire increases and the fuel economy performance is reduced. The thickness of the first layer is more preferably 0.05 mm or more and 0.4 mm or less.

The first layer can be obtained by film-forming the first D polymer composition by a conventional method of film-forming a thermoplastic resin such as extrusion molding or calendar molding, or a thermoplastic elastomer.
(2nd layer)
The second layer is composed of a second D polymer composition containing a styrene-isobutylene diblock copolymer (hereinafter also referred to as SIB), and has a thickness of 0.01 mm or more and 0.3 mm or less.

The content of SIB in the second D polymer composition is preferably 60% by mass or more and 100% by mass or less in the polymer component. If the content of SIB is less than 60% by mass, the viscosity may be high, and extrusion processability may be deteriorated. The content of SIB is more preferably 80% by mass or more and 100% by mass or less.
(SIBS modified copolymer)
Similarly to the first layer, the second D polymer composition is an acid chloride or acid anhydride-modified SIBS modified copolymer in which the styrene block portion of the styrene-isobutylene-styrene block copolymer has an unsaturated bond. Can be included.

The content of the SIBS modified copolymer is preferably 10% by mass to 99.5% by mass, more preferably 10% by mass to 80% by mass, and still more preferably 30% by mass to 70% by mass in the polymer component of the second D polymer composition. The following are particularly preferred. If the compounding amount of the SIBS modified copolymer is less than 10% by mass of the polymer component, the performance improvement effect by the SIBS modified copolymer is small, while if it exceeds 99.5% by mass, the inner liner and the carcass ply rubber There is a possibility that the vulcanization adhesion with is not sufficient.
(Polymer component)
The second D polymer composition can contain, as a polymer component, polymers other than SIB and SIBS modified copolymers. For example, as with the first D polymer composition, thermoplastic elastomers, particularly styrenic thermoplastic elastomers, are suitably used.

The second D polymer composition can mix a rubber component as a polymer component. The rubber component preferably contains at least one selected from the group consisting of natural rubber, isoprene rubber, chloroprene rubber and butyl rubber. The blending amount of the rubber component is preferably in the range of 5 to 20 parts by mass with respect to 100 parts by mass of the thermoplastic elastomer component.
(Other ingredients)
Similar to the first D polymer composition, the second D polymer composition can contain a crosslinking agent, a coagent, a filler, an antiaging agent, a softener, a processing aid, and the like.
(Thickness of second layer)
The thickness of the second layer can be 0.01 mm or more and 0.3 mm or less. Here, the thickness of the second layer means the average thickness of the second layer. When the thickness of the second layer is less than 0.01 mm, the second layer may be broken by the press pressure at the time of vulcanization of the green tire on which the inner liner is disposed, and the vulcanization adhesion may be reduced. On the other hand, if the thickness of the second layer exceeds 0.3 mm, the weight of the tire increases and the fuel economy performance decreases. The thickness of the second layer is more preferably 0.05 mm or more and 0.2 mm or less.

The second layer can be obtained by film-forming the second D polymer composition by a conventional method of film-forming a thermoplastic resin such as extrusion molding, calendar molding, or a thermoplastic elastomer.
<Placement of inner liner>
Inner liner PL is comprised from 1st layer PL1 and 2nd layer PL2, as shown in FIG. In the case of applying the inner liner PL to a pneumatic tire, when the second layer PL2 is installed outward in the tire radial direction such that the second layer PL2 contacts the carcass ply 61, the second layer PL2 and the carcass 61 are Bond strength can be increased. Therefore, the obtained pneumatic tire can have excellent air permeation resistance and durability because the inner liner and the rubber layer of the carcass ply 61 are well adhered.

<Method of manufacturing inner liner>
The inner liner can be manufactured, for example, by the following method. The first layer and the second layer are produced by extrusion molding, calendar molding or the like. The first layer and the second layer are laminated to produce an inner liner. In addition, pellets of each of the first D polymer composition and the second D polymer composition can be produced by lamination extrusion such as lamination extrusion or coextrusion.

<Method of manufacturing pneumatic tire>
The pneumatic tire according to the fourth embodiment can be manufactured using the same manufacturing method as that of the first embodiment.

<Production of polymer laminate>
According to the specifications shown in Tables 1 to 3, the polymer laminates of Examples and Comparative Examples were produced to evaluate their performance. SIB, SIBS, SIS and epoxidized SBS used for the first layer and the second layer were prepared as follows.

(SIB)
In a 2 L reaction vessel equipped with a stirrer, 589 mL of methylcyclohexane (dried with molecular sieves), 613 ml of n-butyl chloride (dried with molecular sieves), and 0.550 g of cumyl chloride were added. The reaction vessel was cooled to −70 ° C., and then 0.35 mL of α-picoline (2-methylpyridine) and 179 mL of isobutylene were added. Further, 9.4 mL of titanium tetrachloride was added to initiate polymerization, and the solution was reacted at -70 ° C. for 2.0 hours with stirring. Next, 59 mL of styrene was added to the reaction vessel and the reaction was continued for further 60 minutes, and then the reaction was stopped by adding a large amount of methanol. After removing the solvent and the like from the reaction solution, the polymer was dissolved in toluene and washed twice with water. The toluene solution was added to a methanol mixture to precipitate a polymer, and the obtained polymer was dried at 60 ° C. for 24 hours to obtain a styrene-isobutylene diblock copolymer.

Styrene component content: 15% by mass
Weight average molecular weight: 70,000
(SIBS)
“Sibustar SIBSTAR 102 (Shore A hardness 25; styrene component content 25 mass%, weight average molecular weight: 100,000)” manufactured by Kaneka Co., Ltd. was used.

In Examples 1-23, SIBS having a weight average molecular weight of 200,000 and a weight average molecular weight of 300,000 were used.

(SIS)
D1161 JP (content of styrene component: 15% by mass, weight average molecular weight: 150,000) manufactured by Kraton Polymer Ltd. was used.

(Epoxidized SBS)
Prepared “Epofriend A1020” (epoxidized styrene-butadiene-styrene triblock copolymer, weight average molecular weight 100,000, styrene content 40 mass%, epoxy equivalent 500) manufactured by Daicel Chemical Industries, Ltd. .

Each of the raw material of said 1st layer and 2nd layer was pelletized with the twin-screw extruder (screw diameter: (phi) 50 mm, L / D: 30, cylinder temperature: 220 degreeC). The obtained pellets are co-extruded using a T-die extruder (screw diameter: φ80 mm, L / D: 50, die grip width: 500 mm, cylinder temperature: 220 ° C.), and the thicknesses shown in Tables 1 to 3 A polymer laminate having the first and second layers of A polymer sheet consisting of only the first layer was prepared as Comparative Example 1-1.

<Production of pneumatic tire>
In order to adjust the thickness Ge of the shoulder position Pe of the inner liner and the thickness Gc of the crown center position Pc, a profile is attached to the extrusion port of the polymer sheet to reduce the thickness Gc of the crown center position Pc. The body was made. The obtained polymer laminate was applied to the inner liner portion of the tire to prepare a green tire. This was disposed on the inner surface of the tire as an inner liner. The polymer laminate was disposed such that the first layer of the polymer laminate was disposed on the innermost side in the radial direction of the green tire, and the second layer was in contact with the carcass layer of the green tire. The green tire was press molded in a mold at 170 ° C. for 20 minutes to produce a 195 / 65R15 size vulcanized tire.

After the vulcanized tire was cooled at 100 ° C. for 3 minutes, the vulcanized tire was removed from the mold to obtain a pneumatic tire.

The following evaluations were performed on the polymer laminate and the pneumatic tire.
<Adhesiveness>
A peeling test was conducted according to JIS K 6256 "Vulcanized rubber and thermoplastic rubber-How to determine adhesion". At first, the polymer laminate and the rubber sheet (compounding: NR / BR / SBR = 40/30/30) are bonded and vulcanized so that the second layer of the polymer laminate is in contact with the rubber sheet, and the peeling test A piece was made. The peeling test was done using the obtained test piece, and the adhesive force of the polymer laminated body and the rubber sheet was measured. The size of the test piece was 25 mm wide, and was performed under a room temperature condition of 23 ° C. The adhesion index was calculated according to the following formula using the obtained numerical value as a reference (100) for Comparative Example 1-1. The larger the value, the better the adhesion.

(Adhesive index) = (Adhesive power of each polymer laminate) / (Adhesive power of Comparative Example 1-1) × 100
<Rolling resistance>
For rolling resistance, tan δ of each polymer laminate is measured under the conditions of a temperature of 70 ° C., an initial strain of 10%, and a dynamic strain of 2% using a viscoelasticity spectrometer VES (IWAMOTO MFG. Co., Ltd.). Assuming that tan δ of -1 is 100, the index is displayed according to the following formula. The larger the index, the lower the rolling resistance.

(Rolling resistance index) = (tan δ of Comparative Example 1-1) / (tan δ of each polymer laminate) × 100
<Low temperature durability>
The low-temperature durability is measured by measuring the distance traveled when a crack occurs in the inner liner under the conditions of an ambient temperature of -20 ° C, a tire pressure of 120 kPa, a load load ratio of 60% and a velocity of 80 Km / h. Based on the travel distance of the above, the index is displayed by the following formula. The higher the value, the better the low temperature durability.

(Low-temperature durability index) = (travel distance of each pneumatic tire) / (travel distance of comparative example 1-1) x 100
<Static air pressure reduction rate>
The pneumatic tire was assembled to a JIS standard rim 15 × 6 JJ, sealed with an initial air pressure of 300 Kpa, and left at room temperature for 90 days to calculate the reduction rate of the air pressure.

<With or without air in>
The inside of the vulcanized tire was visually inspected and evaluated according to the following criteria.

A: The number of air-ins is zero.
B: The number of air-ins having a diameter of 5 mm or less is 1 to 3.

C: The number of air-ins having a diameter of 5 mm or less is 4 or more, or the number of air-ins having a diameter of 5 mm or more is 1 or more.

The results are shown in Tables 1 to 3.

(* 1) In the uneven thickness range (CL (%) / SW (%)), CL (%) and SW (%) indicate the following.

CL (%) = the distance from the shoulder position Pe of the thick portion to the crown center position Pc side / shoulder distance Wc × 100
SW (%) = the distance from the shoulder position Pe of the thick portion to the maximum width position Ps side / side distance Ws × 100
<Evaluation result>
Comparative Example 1-1 is a polymer sheet made of SIBS and was used as a reference.

In Examples 1-1 to 1-3 and 1-10 to 1-24, the first layer contains SIBS and epoxidized SBS. While having the air permeability resistance equivalent to Comparative Example 1-1, the adhesion and the low temperature durability were improved, and the rolling resistance was reduced.

Examples 1-4 to 1-6, the second layer comprises SIS and epoxidized SBS. While having the air permeability resistance equivalent to Comparative Example 1-1, the adhesion and the low temperature durability were improved, and the rolling resistance was reduced.

Examples 1-7 to 1-9, the second layer comprises SIB and epoxidized SBS. While having the air permeability resistance equivalent to Comparative Example 1-1, the adhesion and the low temperature durability were improved, and the rolling resistance was reduced.

<Production of polymer laminate>
The polymer laminates of Examples and Comparative Examples were manufactured according to the specifications shown in Tables 4 to 8 to evaluate their performance. The SIB, SIBS, and tackifier used for the first layer and the second layer were prepared as follows.

(Tackifier)
Tackifier A: "Arcon P 140 (C9 petroleum resin, softening point 140 ° C., weight average molecular weight 900)" manufactured by Arakawa Chemical Industries, Ltd. was used.

Tackifier B: “YS resin PX1250 (terpene resin, softening point 125 ° C., weight average molecular weight 700)” manufactured by Yasuhara Chemical Co., Ltd. was used.

Tackifier C: "Superester A 125 (hydrogenated rosin ester, softening point 125 ° C., weight average molecular weight 700)" manufactured by Arakawa Chemical Industries, Ltd. was used.

Each of the raw material of said 1st layer and 2nd layer was pelletized with the twin-screw extruder (screw diameter: (phi) 50 mm, L / D: 30, cylinder temperature: 220 degreeC). The obtained pellets were co-extruded using a T-die extruder (screw diameter: φ80 mm, L / D: 50, die grip width: 500 mm, cylinder temperature: 220 ° C.), and the thicknesses shown in Tables 4 to 8 A polymer laminate having a first layer and a second layer was prepared.

The following evaluations were performed on the polymer laminate and the pneumatic tire.
[Examples 2-1 to 2-21, Comparative Examples 2-1 to 2-49]
<Vulcanization adhesive strength>
A peeling test was conducted according to JIS K 6256 "Vulcanized rubber and thermoplastic rubber-How to determine adhesion". At first, the polymer laminate and the rubber sheet (compounding: NR / BR / SBR = 40/30/30) are bonded and vulcanized so that the second layer of the polymer laminate is in contact with the rubber sheet, and the peeling test A piece was made. The peeling test was done using the obtained test piece, and the adhesive force of the polymer laminated body and the rubber sheet was measured. The size of the test piece was 25 mm wide, and was performed under a room temperature condition of 23 ° C. The vulcanized adhesion index was calculated by the following formula using the obtained numerical value as a reference (100) for Comparative Example 2-1. The larger the value, the better the adhesion.

(Vulcanized adhesion index) = (adhesive strength of each polymer laminate) / (adhesive strength of comparative example 2-1) × 100
<Rolling resistance>
For rolling resistance, tan δ of each polymer laminate is measured under the conditions of a temperature of 70 ° C., an initial strain of 10%, and a dynamic strain of 2% using a visco-elastic spectrometer VES (manufactured by Iwamoto Seisakusho Co., Ltd.). Assuming that tan δ of -1 is 100, the index is displayed according to the following formula. The larger the index, the lower the rolling resistance.

(Rolling resistance index) = (tan δ of Comparative Example 2-1) / (tan δ of each polymer laminate) × 100
<Bending crack growth property>
Flexural crack growth was evaluated by whether the inner liner was broken or peeled off. The prototype tire is assembled on a JIS standard rim 15 x 6 JJ, the internal pressure of the tire is set to 150 KPa lower than usual, the load is 600 kg, the speed is 100 km / h, the inside of the tire is observed with a traveling distance of 20,000 km, The number of peels was measured. Based on Comparative Example 2-1, the crack growth of each composition was indicated by an index. The larger the index value, the smaller the flex crack growth is.

(Bending crack growth index) = (the number of cracks in Comparative Example 2-1) / (the number of cracks in each tire) × 100
<Static air pressure reduction rate>
A 195 / 65R15 steel radial PC tire is assembled on a JIS standard rim 15 × 6JJ, sealed with an initial air pressure of 300 KPa, left at room temperature for 90 days, and the reduction rate of the air pressure is calculated. Based on Comparative Example 2-1, the static air pressure drop rate of each composition was indicated as an index. The higher the value of the index, the lower the air pressure reduction rate and the better.

(Static air pressure drop rate index) = (Static air pressure drop rate of Comparative Example 2-1) / (Static air pressure drop rate of each tire) × 100
<With or without air in>
The inside of the vulcanized tire was visually inspected and evaluated according to the following criteria.

[Examples 2-22 and 2-23, Comparative Examples 2-50 to 2-52]
The above items were evaluated based on Comparative Example 2-50 in Examples 2-22 and 2-23, and Comparative Examples 2-50 to 2-52.

The results are shown in Tables 4-8.

(* 1) The uneven thickness range (CL (%) / SW (%)) indicates the following.
CL (%) = the distance from the shoulder position Pe of the thick portion to the crown center position Pc side / shoulder distance Wc × 100
SW (%) = the distance from the shoulder position Pe of the thick portion to the maximum width position Ps side / side distance Ws × 100
<Evaluation result>
Comparative Example 2-1 is a polymer laminate having a first layer made of SIBS and a second layer made of SIB, and a pneumatic tire, which was used as a reference.

Examples 2-1 to 2-21 are a polymer laminate and a pneumatic tire in which the first layer or the second layer contains 20 parts by mass of a tackifier. In all cases, while maintaining the rolling resistance equivalent to that of Comparative Example 2-1, the vulcanization adhesion, the resistance to flex crack growth, the air permeability, and the air-in did not occur.

Comparative Example 2-50 is a polymer laminate having a first layer of 8 mm in thickness made of SIBS, and a second layer of 8 mm in thickness containing SIB, SIBS, and a tackifier, and was used as a reference.

Examples 2-22 and 2-23 are a polymer laminate and a pneumatic tire in which the thickness of the first layer and the second layer is 0.05 mm, respectively. As compared with Comparative Example 2-50, the vulcanized adhesive strength and the air permeation resistance were improved, and the generation of air-in could be suppressed.

<Preparation of polymer component>
The polymer components used for the first and second layers were prepared as follows.
<Isobutylene-based modified copolymer>
(Component A-1)
Component A-1: (styrene / β-pinene) -isobutylene- (styrene / β-pinene) block copolymer (β-pinene content: 9.7% by mass, number average molecular weight (Mn): 103,000).

The production method of component A-1 is as follows.
After replacing the inside of a 2 L separable flask with nitrogen, add 31.0 mL of n-hexane and 294.6 mL of similarly dried butyl chloride, which were dried with molecular sieves using a syringe, After being placed in a mixed bath of dry ice and methanol at 0 ° C and cooled, the pressure tube made of Teflon (registered trademark) is transferred to a pressure collecting glass made of pressure glass with 88.9 mL (941.6 mmol) of isobutylene monomer. Were connected, and the isobutylene monomer was fed into the polymerization vessel by nitrogen pressure. 0.148 g (0.6 mmol) of p-dicumyl chloride and 0.07 g (0.8 mmol) of α-picoline were added. Further, 0.87 mL (7.9 mmol) of titanium tetrachloride was added to initiate polymerization. Stirring was performed at the same temperature for 1.5 hours from the start of polymerization, and then 1 mL of the polymerization solution was withdrawn as a sample from the polymerization solution. Then, 10.4 g (99.4 mmol) of styrene monomer and 6.8 g (49.7 mmol) of β-pinene which had been cooled to -70 ° C. were uniformly stirred and then added to the polymerization vessel. After 45 minutes of addition of styrene and β-pinene, about 40 mL of methanol was added to complete the reaction. After evaporating the solvent and the like from the reaction solution, it was dissolved in toluene and washed twice with water. The toluene solution was then added to a large amount of methanol to precipitate the polymer, and the resulting product was vacuum dried at 60 ° C. for 24 hours. The molecular weight of the block copolymer obtained by the GPC method was measured. The number average molecular weight (Mn) is 103,000, and Mw / Mn is 1.21.
(Component A-2)
Component A-2: (styrene / β-pinene) -isobutylene- (styrene / β-pinene) block copolymer (β-pinene content: 5.3% by mass, number average molecular weight: 107,000).

The production method of component A-2 is as follows.
After replacing the inside of a 2 L separable flask with nitrogen, 31.0 mL of n-hexane and 294.6 mL of similarly dried butyl chloride, which were dried with molecular sieves using a syringe, were added, and the polymerization container was heated to -70 ° C. The mixture was placed in a mixed bath of dry ice and methanol and cooled, and a Teflon (registered trademark) liquid transfer tube was placed in a pressure glass liquefaction sampling tube with a three-way cock containing 88.9 mL (941.6 mmol) of isobutylene monomer. It connected and the isobutylene monomer was sent by nitrogen pressure in the polymerization container. 0.148 g (0.6 mmol) of p-dicumyl chloride and 0.07 g (0.8 mmol) of α-picoline were added.

Next, 0.87 mL (7.9 mmol) of titanium tetrachloride was added to initiate polymerization. After stirring at the same temperature for 1.5 hours from the start of polymerization, 1 mL of the polymerization solution was withdrawn as a sample from the polymerization solution. Then, 10.4 g (99.4 mmol) of styrene monomer and 3.6 g (26.3 mmol) of β-pinene cooled to -70 ° C. were uniformly stirred and then added to the polymerization vessel. After 45 minutes of addition of styrene and β-pinene, about 40 mL of methanol was added to complete the reaction. After evaporating the solvent and the like from the reaction solution, it was dissolved in toluene and washed twice with water. Further, the toluene solution was added to a large amount of methanol to precipitate a polymer, and the obtained polymer was vacuum dried at 60 ° C. for 24 hours. The molecular weight of the block polymer obtained by the GPC method was measured. The block copolymer has a number average molecular weight (Mn) of 107,000 and Mw / Mn of 1.23.
(Component A-3)
Component A-3: Styrene- (isobutylene / β-pinene) -styrene block copolymer (β-pinene content 5.3% by mass, number average molecular weight 109,000).

The production method of component A-3 is as follows.
After replacing the inside of the polymerization vessel of a 2 L separable flask with nitrogen, add 31.0 mL of n-hexane and 294.6 mL of butyl chloride dried with molecular sieves, which are dried with molecular sieves using a syringe, After cooling in a mixed bath of dry ice and methanol at −70 ° C., 3.6 g (26.3 mmol) of β-pinene was added.

Next, connect a Teflon (registered trademark) liquid transfer tube to a pressure glass liquefied sampling tube with three-way cock containing 88.9 mL (941.6 mmol) of isobutylene monomer, and press the isobutylene monomer in the polymerization container with nitrogen pressure It was sent. Further, 0.148 g (0.6 mmol) of p-dicumyl chloride and 0.07 g (0.8 mmol) of α-picoline were added. Next, 0.87 mL (7.9 mmol) of titanium tetrachloride was further added to initiate polymerization. After 45 minutes from the start of polymerization, 10.4 g (99.4 mmol) of styrene monomer cooled to -70.degree. C. were added into the polymerization vessel. The reaction was terminated 45 minutes after the addition of styrene by adding about 40 mL of methanol. After evaporating the solvent and the like from the reaction solution, it was dissolved in toluene and washed twice with water. Further, the toluene solution was added to a large amount of methanol to precipitate a polymer, and the obtained polymer was vacuum dried at 60 ° C. for 24 hours. The molecular weight of the block copolymer obtained by the GPC method was measured. The number average molecular weight (Mn) of the block copolymer is 109,000, and Mw / Mn is 1.21.
<SIB>
In a 2 L reaction vessel equipped with a stirrer, 589 mL of methylcyclohexane (dried with molecular sieves), 613 ml of n-butyl chloride (dried with molecular sieves), and 0.550 g of cumyl chloride were added. The reaction vessel was cooled to −70 ° C., and then 0.35 mL of α-picoline (2-methylpyridine) and 179 mL of isobutylene were added. Further, 9.4 mL of titanium tetrachloride was added to initiate polymerization, and the solution was reacted at -70 ° C. for 2.0 hours with stirring. Next, 59 mL of styrene was added to the reaction vessel and the reaction was continued for further 60 minutes, and then the reaction was stopped by adding a large amount of methanol. After removing the solvent and the like from the reaction solution, the polymer was dissolved in toluene and washed twice with water. The toluene solution was added to a methanol mixture to precipitate a polymer, and the obtained polymer was dried at 60 ° C. for 24 hours to obtain a styrene-isobutylene diblock copolymer (styrene component content: 15% by mass) , Weight average molecular weight: 70,000).
<SIBS>
“Sibustar SIBSTAR 102T (styrene-isobutylene-styrene block copolymer, Shore A hardness: 25, content of styrene component: 25% by mass, weight average molecular weight: 100,000)” manufactured by Kaneka Co., Ltd. was used.
<Production of inner liner>
Prepare a polymer component according to the formulation shown in Tables 9 to 16, and add the following components, and then add a Banbury mixer, a kneader, a twin screw extruder (screw diameter: φ 50 mm, L / D: 30, cylinder temperature: Blending at 220 ° C.) gave a polymer composition. Then, after producing the polymer sheet of the 1st layer and the 2nd layer with T die extrusion machine (screw diameter: φ 80 mm, L / D: 50, die lip width: 500 mm, cylinder temperature: 220 ° C), they are pasted together and inner A liner was made. In addition, the thickness of the polymer sheet of a 1st layer and a 2nd layer shows average thickness.
(Compounding agent and amount of 1st layer)
The compounding amount is described as an amount based on 100 parts by weight in total of SIBS and the isobutylene-based modified copolymer.

IIR ("Exxon Mobil Co., Ltd." Exxon chlorobutyl 1068 "): 70 parts by mass Carbon black (" Toast Carbon Co., Ltd. "" Seat V "): 70 parts by mass Zinc oxide (Mitsui Metal Mining Co., Ltd.) "Zinc flower No. 1": 5 parts by mass Stearic acid ("Rannac S30 Stearate" manufactured by Kao Corporation): 2 parts by mass Anti-aging agent ("NOCRAC 6C" manufactured by Ouchi Emerging Chemical Co., Ltd.): 0.2 Parts by mass Vulcanization accelerator ("Noxusella DM" manufactured by Ouchi Emerging Chemical Co., Ltd.): 2.5 parts by mass Sulfur ("powder sulfur" manufactured by Tsurumi Chemical Industry Co., Ltd.): 1 part by mass Antiblocking agent (C9 petroleum resin) Arakawa Chemical Industries, Ltd. "Alcon P 140", softening point: 140 ° C, weight average molecular weight: 900: 5 parts by mass (compounding agents and amounts of the second layer)
The compounding amount is described as an amount based on 100 parts by mass of SIB and SIBS in total.

IIR ("Exxon Mobil Co., Ltd." Exxon chlorobutyl 1068 "): 70 parts by mass Carbon black (" Toast Carbon Co., Ltd. "" Seast V "): 50 parts by mass Zinc oxide (Mitsui Metal Mining Co., Ltd.) "Zinc flower No. 1": 5 parts by mass Stearic acid ("Rannac S30 Stearate" manufactured by Kao Corporation): 2 parts by mass Anti-aging agent ("NOCRAC 6C" manufactured by Ouchi Emerging Chemical Co., Ltd.): 0.2 Parts by mass Vulcanization accelerator ("Noxusella DM" manufactured by Ouchi Emerging Chemical Co., Ltd.): 1 part by mass Sulfur ("powder sulfur" manufactured by Tsurumi Chemical Industry Co., Ltd.): 1 part by mass Antiblocking agent (C9 petroleum resin, Arakawa Chemical Industry Co., Ltd. "Alcon P140", softening point: 140 ° C, weight average molecular weight: 900): 5 parts by mass <Preparation of tire>
The inner liner was applied to the inner liner portion of the tire to produce a green tire, which was press molded at 170 ° C. for 20 minutes and then quenched at 100 ° C. for 3 minutes to produce a 195 / 65R15 size tire.
[Evaluation test]
Each composition was tested for vulcanization adhesion of the inner liner, rolling resistance, flex crack growth of the pneumatic tire, static air pressure reduction rate, and presence of air-in. Examples 3-1 to 3-24 and Comparative Examples 3-1 to 3-47 are based on Comparative Example 3-1, and Examples 3-25 and 3-26, and Comparative Examples 3-48 to 3-50. Was evaluated based on Comparative Example 3-48. Details of each test are shown below.
<Vulcanization adhesive strength>
Tests were conducted in accordance with JIS-K-6256 “How to Determine Adhesion of Vulcanized Rubber and Thermoplastic Rubber”. Specifically, the inner liner and the rubber sheet are laminated and vulcanized at 170 ° C. for 20 minutes. The adhesion was measured at the bonding interface after vulcanization. The results are expressed as an index, and the higher the value, the greater the adhesion and the better.
Vulcanizing adhesive strength (index) = (vulcanizing adhesive strength of each composition) / (vulcanizing adhesive strength of Comparative Example 3-1 or Comparative Example 3-48) × 100
The composition of the rubber sheet is as follows.

Natural rubber (Note 1) 100 parts by mass Carbon black (Note 2) 50 parts by mass Zinc white (Note 3) 3 parts by mass Antidegradant (Note 4) 0.2 parts by mass Sulfur (Note 5) 1 part by mass Vulcanization acceleration Agent (Note 6) 1 part by mass Vulcanization auxiliary (Note 7) 1 part by mass (Note 1) TSR 20
(Note 2) “Seast V” manufactured by Tokai Carbon Co., Ltd. (N 660, N ₂ SA: 27 m ² / g)
(Note 3) Zinc oxide (ZnO): "Zinc flower No. 1" manufactured by Mitsui Mining & Smelting Co., Ltd.
(Note 4) Nocchi 6C, made by Ouchi emerging chemical company
(Note 5) "Powder sulfur" manufactured by Tsurumi Chemical Industries, Ltd.
(Note 6) "Nocceller DM" manufactured by Ouchi Emerging Chemical Company
(Note 7) Stearic acid: Kao Corporation "Runac Stearate S30"
<Rolling resistance>
The tan δ of each formulation was measured under the conditions of a temperature of 70 ° C., an initial strain of 10%, and a dynamic strain of 2% using a viscoelastic spectrometer VES (manufactured by Iwamoto Seisakusho Co., Ltd.), and Comparative Example 3-1 or Comparative Example Assuming that tan δ of 3-48 is 100, index display is performed according to the following formula. As the index is larger, the rolling is reduced.
Rolling resistance (index) = (tan δ of Comparative Example 3-1 or Comparative Example 3-48) / (tan δ of each composition) × 100
<Bending crack growth property>
Flexural crack growth was evaluated by whether the inner liner was broken or peeled off. The prototype tire is assembled on a JIS standard rim 15 x 6 JJ, the internal pressure of the tire is set to 150 KPa lower than usual, the load is 600 kg, the speed is 100 km / h, the inside of the tire is observed with a traveling distance of 20,000 km, The number of peels was measured. Based on Comparative Example 3-1 or Comparative Example 3-48, the crack growth of each composition was indicated by an index. The larger the index value, the smaller the flex crack growth is.
Flexural crack growth (index) = (number of cracks in Comparative Example 3-1 or Comparative Example 3-48) / (number of cracks in each composition) × 100
<Static air pressure reduction rate>
A 195 / 65R15 steel radial PC tire was assembled on a JIS standard rim 15 × 6JJ, sealed with an initial air pressure of 300 KPa, left at room temperature for 90 days, and the decrease rate of the air pressure was calculated. The results are expressed as an index, and the higher the value, the lower the rate of decrease in air pressure and the better.
Static air pressure reduction rate (index) = (Static air pressure reduction rate of Comparative Example 3-1 or Comparative Example 3-48) / (Static air pressure reduction rate of each composition) × 100
<With or without air in>
The inside of the vulcanized tire was inspected, and in terms of appearance, the air-in was A for one tire, B for one or more and three or less, and C for four or more. The size of the air-in was 5 mm or less in diameter, and when there was air-in exceeding 5 mm in diameter, even one air-in was C.

The results are shown in Tables 9-16.

In the table, the uneven thickness range (CL (%) / SW (%)) indicates the following.
CL (%) = the distance from the shoulder position Pe of the thick portion to the crown center position Pc side / shoulder distance Wc × 100
SW (%) = the distance from the shoulder position Pe of the thick portion to the maximum width position Ps side / side distance Ws × 100
<Evaluation result>
Examples 3-1 to 3-26 in which the polymer component of the first layer contains 0.5% by mass or more and 25% by mass of the component A-1, A-2 or A-3 (isobutylene-based modified copolymer) are It was found that the vulcanized adhesion, the resistance to flex crack growth, the static air pressure reduction rate were excellent, and the air-in was also suppressed. Furthermore, when the second layer had the same composition and the tire structure was also the same, comparing the example with the comparative example, it was found that the example had a low rolling resistance.

The pneumatic tires of the comparative example and the example were manufactured according to the specifications shown in Tables 17 to 19, and the performance was evaluated. The polymer components SIBS, SIBS modified copolymer and SIB were prepared as follows.
[SIBS]
"SHIBSTER SIBSTAR 102T (Shore A hardness 25, Styrene content: 15% by mass, weight average molecular weight: 100,000)" manufactured by Kaneka Co., Ltd. was used.
[SIBS modified copolymer]
In a 2 liter separable flask, 75 g of styrene-isobutylene block copolymer (styrene content: 30%, mole number of styrene unit: 0.216 mol) was placed, and the inside of the container was replaced with nitrogen. Using a syringe, 1200 mL of n-hexane dried with molecular sieves and 1800 mL of n-butyl chloride dried with molecular sieves were added.

Next, 30 g (0.291 mol) of methacrylic acid chloride was added using a syringe. The reaction was initiated by adding 39.4 g (0.295 mol) of aluminum trichloride while stirring the solution. After the reaction for 30 minutes, about 1000 ml of water was added to the reaction solution and the reaction was vigorously stirred to terminate the reaction. The reaction solution is washed with a large amount of water several times, and then gradually dropped into a large amount of methanol and acetone mixed solvent (1: 1) to precipitate a reaction product, and then the reaction product is vacuumed at 60 ° C. for 24 hours Drying gave a SIBS modified copolymer (weight average molecular weight: 150,000, styrene component content: 20% by mass, acid chloride: 1.0% by mass).
[SIB]
In a 2 L reaction vessel equipped with a stirrer, 589 mL of methylcyclohexane (dried with molecular sieves), 613 ml of n-butyl chloride (dried with molecular sieves), and 0.550 g of cumyl chloride were added. The reaction vessel was cooled to −70 ° C., and then 0.35 mL of α-picoline (2-methylpyridine) and 179 mL of isobutylene were added. Further, 9.4 mL of titanium tetrachloride was added to initiate polymerization, and the solution was reacted at -70 ° C. for 2.0 hours with stirring. Next, 59 mL of styrene was added to the reaction vessel and the reaction was continued for further 60 minutes, and then the reaction was stopped by adding a large amount of methanol. After removing the solvent and the like from the reaction solution, the polymer was dissolved in toluene and washed twice with water. The toluene solution was added to a methanol mixture to precipitate a polymer, and the obtained polymer was dried at 60 ° C. for 24 hours to obtain a styrene-isobutylene diblock copolymer (styrene component content: 15% by mass) , Weight average molecular weight: 70,000).
<Production of inner liner>
Prepare a polymer component according to the formulation shown in Tables 17-19, and add the following ingredients, and then add a Banbury mixer, kneader, twin-screw extruder (screw diameter: φ 50 mm, L / D: 30, cylinder temperature: Blending at 220 ° C.) gave a polymer composition. Then, after producing the polymer sheet of the 1st layer and the 2nd layer with T die extrusion machine (screw diameter: φ 80 mm, L / D: 50, die lip width: 500 mm, cylinder temperature: 220 ° C), they are pasted together and inner A liner was made. In addition, the thickness of the polymer sheet of a 1st layer and a 2nd layer shows average thickness.
(Compounding agent and amount of 1st layer)
The compounding amount is described as an amount based on a total of 100 parts by mass of SIBS and SIBS modified copolymer.

Carbon black ("Seat V" manufactured by Tokai Carbon Co., Ltd.): 70 parts by mass Zinc oxide ("Zinc flower No. 1" manufactured by Mitsui Mining & Smelting Co., Ltd.): 5 parts by mass Stearic acid (manufactured by Kao Corp.) "Stearate lunac S30": 2 parts by mass Antiaging agent ("NOCRAC 6C" manufactured by Ouchi Shinko Chemical Co., Ltd.): 0.2 parts by mass Vulcanization accelerator ("NOCSELER DM" manufactured by Ouchi Shinko Chemical Co., Ltd.): 2 .5 parts by mass Sulfur ("powdered sulfur" manufactured by Tsurumi Chemical Industry Co., Ltd.): 1 part by mass (compounding agents and amounts of the second layer)
The compounding amount is described as an amount based on a total of 100 parts by mass of the SIB and SIBS modified copolymer.

Carbon black ("Seast V" manufactured by Tokai Carbon Co., Ltd.): 50 parts by mass Zinc oxide ("Zinc flower No. 1" manufactured by Mitsui Mining & Smelting Co., Ltd.): 5 parts by mass Stearic acid (manufactured by Kao Corporation) "Stearate lunac S30": 2 parts by mass Antiaging agent ("NOCRAC 6C" manufactured by Ouchi Shinko Chemical Co., Ltd.): 0.2 parts by mass Vulcanization accelerator ("NOCSELER DM" manufactured by Ouchi Shinko Chemical Co., Ltd.): 1 Mass part Sulfur ("Powder sulfur" manufactured by Tsurumi Chemical Industry Co., Ltd.): 1 part by mass <Production of tire>
The inner liner was applied to the inner liner portion of the tire to produce a green tire, which was press molded at 170 ° C. for 20 minutes and then quenched at 100 ° C. for 3 minutes to produce a 195 / 65R15 size tire.
[Evaluation test]
Each composition was tested for vulcanization adhesion of the inner liner, rolling resistance, flex crack growth of the pneumatic tire, static air pressure reduction rate, and presence of air-in.
<Vulcanization adhesive strength>
Tests were conducted in accordance with JIS-K-6256 “How to Determine Adhesion of Vulcanized Rubber and Thermoplastic Rubber”. Specifically, the inner liner and the rubber sheet are laminated and vulcanized at 170 ° C. for 20 minutes. The adhesion was measured at the bonding interface after vulcanization. The results are expressed as an index, and the higher the value, the greater the adhesion and the better.
Vulcanizing adhesive strength (index) = (vulcanizing adhesive strength of each composition) / (vulcanizing adhesive strength of Comparative Example 4-1) × 100
The composition of the rubber sheet is as follows.

Natural rubber (Note 1) 100 parts by mass Carbon black (Note 2) 50 parts by mass Zinc white (Note 3) 3 parts by mass Antidegradant (Note 4) 0.2 parts by mass Sulfur (Note 5) 1 part by mass Vulcanization acceleration Agent (Note 6) 1 part by mass Vulcanization auxiliary (Note 7) 1 part by mass (Note 1) TSR 20
(Note 2) “Seast V” manufactured by Tokai Carbon Co., Ltd. (N 660, N ₂ SA: 27 m ² / g)
(Note 3) Zinc oxide (ZnO): "Zinc flower No. 1" manufactured by Mitsui Mining & Smelting Co., Ltd.
(Note 4) Nocchi 6C, made by Ouchi emerging chemical company
(Note 5) "Powder sulfur" manufactured by Tsurumi Chemical Industries, Ltd.
(Note 6) "Nocceller DM" manufactured by Ouchi Emerging Chemical Company
(Note 7) Stearic acid: Kao Corporation "Runac Stearate S30"
<Rolling resistance>
The tan δ of each formulation was measured under the conditions of a temperature of 70 ° C., an initial strain of 10%, and a dynamic strain of 2% using a viscoelastic spectrometer VES (manufactured by Iwamoto Seisakusho Co., Ltd.), and tan δ of Comparative Example 4-1 was measured. The index is indicated by the following formula as 100. As the index is larger, the rolling is reduced.
Rolling resistance (index) = (Comparative example 4-1) / (tan δ of each composition) × 100
<Bending crack growth property>
Flexural crack growth was evaluated by whether the inner liner was broken or peeled off. The prototype tire is assembled on a JIS standard rim 15 x 6 JJ, the internal pressure of the tire is set to 150 KPa lower than usual, the load is 600 kg, the speed is 100 km / h, the inside of the tire is observed with a traveling distance of 20,000 km, The number of peels was measured. Based on Comparative Example 4-1, the crack growth of each composition was indicated by an index. The larger the index value, the smaller the flex crack growth is.
Flexural crack growth (index) = (number of cracks of Comparative Example 4-1) / (number of cracks of each composition) × 100
<Static air pressure reduction rate>
A 195 / 65R15 steel radial PC tire was assembled on a JIS standard rim 15 × 6JJ, sealed with an initial air pressure of 300 KPa, left at room temperature for 90 days, and the decrease rate of the air pressure was calculated. The results are expressed as an index, and the higher the value, the lower the rate of decrease in air pressure and the better.
Static air pressure decrease rate (index) = (Static air pressure decrease rate of each composition) / (Static air pressure decrease rate of Comparative Example 4-1) × 100
<With or without air in>
The inside of the vulcanized tire was inspected, and in terms of appearance, the air-in was A for one tire, B for one or more and three or less, and C for four or more. The size of the air-in was 5 mm or less in diameter, and when there was air-in exceeding 5 mm in diameter, even one air-in was C.

The results are shown in Tables 17-19

In the table, the uneven thickness range (CL (%) / SW (%)) indicates the following.
CL (%) = the distance from the shoulder position Pe of the thick portion to the crown center position Pc side / shoulder distance Wc × 100
SW (%) = the distance from the shoulder position Pe of the thick portion to the maximum width position Ps side / side distance Ws × 100
<Evaluation result>
In Examples 4-1 to 4-19 in which the polymer component of at least one of the first layer and the second layer contains 10% by mass or more and 99.5% by mass or less of the SIBS modified copolymer, the vulcanization adhesion and the resistance to It was found that flex crack growth and static air pressure reduction rate were excellent, and air-in was also suppressed.

The pneumatic tire of the present invention can be used as a pneumatic tire for trucks, buses, heavy machinery, etc. besides pneumatic tires for passenger cars.

It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is shown not by the above description but by the scope of claims, and is intended to include all modifications within the scope and meaning equivalent to the scope of claims.

Reference Signs List 1 pneumatic tire, 2 tread portion, 3 sidewall portion, 4 bead portion, 5 bead core, 6 carcass ply, 7 belt layer, 8 bead apex, 9 inner liner, PL polymer laminate, PL1 first layer, PL2 second Layer, Pe shoulder position, Pc crown center position, Ps tire maximum width position, Te tread contact edge, Wc shoulder distance, Ws side distance.

Claims

A pneumatic tire comprising an inner liner on the inner side of a carcass ply tire mounted between a pair of bead portions, comprising:
The inner liner comprises a polymer laminate,
The polymer laminate comprises a first layer of a first A polymer composition containing a styrene-isobutylene-styrene triblock copolymer, and a first layer having a thickness of 0.05 mm or more and 0.8 mm or less;
And a second layer having a thickness of 0.01 mm or more and 0.8 mm or less comprising a second A polymer composition containing at least one of styrene-isoprene-styrene triblock copolymer and styrene-isobutylene diblock copolymer,
At least one of the first A polymer composition and the second A polymer composition contains 0.5% by mass or more and 40% by mass or less of an epoxidized styrene-butadiene-styrene triblock copolymer,
The second layer is disposed in contact with the rubber layer of the carcass ply,
In the inner liner, the thickness Ge of the shoulder position Pe is larger than the thickness Gc at the crown center position Pc,
The thickness Ge is 0.2 mm or more and 1.9 mm or less.
Pneumatic tire.
The epoxidized styrene-butadiene-styrene triblock copolymer has a weight average molecular weight of 10,000 or more and 400,000 or less, a styrene component content of 10% by mass or more and 30% by mass or less, and an epoxy equivalent of 50 or more The pneumatic tire according to claim 1, which is 1,000 or less.
A pneumatic tire comprising an inner liner on the inner side of a carcass ply tire mounted between a pair of bead portions, comprising:
The inner liner comprises a polymer laminate,
The polymer laminate comprises a first layer having a thickness of 0.05 mm or more and 0.6 mm or less, which is made of a first B polymer composition containing a styrene-isobutylene-styrene triblock copolymer,
And a second layer having a thickness of 0.01 mm or more and 0.3 mm or less comprising a second B polymer composition containing a styrene-isobutylene diblock copolymer,
At least one of the first B polymer composition and the second B polymer composition contains 0.1 parts by mass or more and 100 parts by mass or less of a tackifier with respect to 100 parts by mass of the polymer component,
The second layer is disposed in contact with the rubber layer of the carcass ply,
In the inner liner, the thickness Ge of the shoulder position Pe is thicker than the thickness Gc at the crown center position Pc,
Pneumatic tire.
The pneumatic tire according to claim 3, wherein the tackifier has a weight average molecular weight of 1 × 10 2 or more and 1 × 10 6 or less and a softening point of 50 ° C. or more and 150 ° C. or less.
A pneumatic tire comprising an inner liner on the inner side of a carcass ply tire mounted between a pair of bead portions, comprising:
The inner liner is
A thickness comprising the first C polymer composition in which the polymer component contains 75% by mass to 99.5% by mass of styrene-isobutylene-styrene triblock copolymer and 0.5% by mass to 25% by mass of isobutylene-based modified copolymer A first layer of 0.05 mm or more and 0.6 mm or less,
Thickness of the polymer composition comprising a second C polymer composition comprising 10% by mass to 100% by mass of a styrene-isobutylene block copolymer and 0% by mass to 90% by mass of a styrene-isobutylene-styrene triblock copolymer. Including a second layer of 01 mm or more and 0.3 mm or less,
The isobutylene-based modified copolymer is a random copolymer comprising a polymer block composed mainly of isobutylene and a polymer block composed mainly of an aromatic vinyl compound, and at least one block is composed of β-pinene. ,
The second layer is disposed in contact with the rubber layer of the carcass ply,
The pneumatic tire wherein the inner liner is thicker at a shoulder position Pe than at a crown center position Pc than at a thickness Gc.
The pneumatic tire according to claim 5, wherein the aromatic vinyl compound of the isobutylene-based modified copolymer is styrene.
A pneumatic tire comprising an inner liner on the inner side of a carcass ply tire mounted between a pair of bead portions, comprising:
The inner liner is
A first layer having a thickness of 0.05 mm or more and 0.6 mm or less comprising a first D polymer composition containing a styrene-isobutylene-styrene triblock copolymer,
And a second layer having a thickness of 0.01 mm or more and 0.3 mm or less comprising a second D polymer composition containing a styrene-isobutylene diblock copolymer,
In at least one of the first D polymer composition and the second D polymer composition, an acid chloride or an acid anhydride having a unsaturated bond in the styrene block portion of the styrene-isobutylene-styrene triblock copolymer in the polymer component is used. 10% by weight or more and 99.5% by weight or less of the SIBS modified copolymer modified with
The second layer is disposed in contact with the rubber layer of the carcass ply,
The pneumatic tire wherein the inner liner is thicker at a shoulder position Pe than at a thickness Gc at a crown central position Pc.
The pneumatic tire according to claim 7, wherein the SIBS modified copolymer has a styrene component content of 10% by mass to 30% by mass, and a weight average molecular weight of 50,000 or more and 400,000 or less.
In the tire meridional section, a normal L is drawn from the ground contact end Te of the tread portion to the tire inner diameter direction with respect to the boundary between the carcass ply and the inner liner, and the intersection with the boundary is the shoulder position Pe. The intersection point between the boundary line between the inner liner and the tire center line CL and the tire center line CL is a crown center position Pc, and a distance along the contour of the inner liner from the shoulder position Pe to the crown center position Pc is a shoulder distance Wc When you
The thick portion of the inner liner is formed in a region having a width of at least 10% of the shoulder distance Wc from the shoulder position Pe to the crown center position Pc side. The pneumatic tire of description.
The pneumatic tire according to claim 9, wherein the thick portion of the inner liner is formed in a region having a width of at least 50% of the shoulder distance Wc from the shoulder position Pe toward the crown center position Pc.
When the distance along the contour of the inner liner from the shoulder position Pe of the inner liner to the tire maximum width position Ps is a side distance Ws, the thick portion of the inner liner is the maximum width from the shoulder position Pe The pneumatic tire according to any one of claims 1 to 10, which is formed in a region having a width of at least 20% of the side distance Ws on the position Ps side.
The pneumatic tire according to claim 11, wherein the thick portion of the inner liner is formed in a region having a width of 100% or less of the side distance Ws on the tire maximum width position Ps side from the shoulder position Pe. .
The pneumatic tire according to any one of claims 1 to 12, wherein the thickness Ge of the shoulder position Pe is 120% or more and 500% or less of the thickness Gc at the crown center position Pc.
The styrene-isobutylene-styrene triblock copolymer has a styrene component content of 10% by mass to 30% by mass, and a weight average molecular weight of 50,000 to 400,000, according to any one of claims 1 to 13. The pneumatic tire as described in a term.