JP2018177169A - tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tire having improved gas barrier property, deformation resistance to heating, and running durability while suppressing the overall thickness, weight and cost. A tire 100 has an annular tire skeleton 10 containing a resin material, a coated rubber layer 22 containing rubber, and a side rubber layer 24 containing rubber, and one side portion of the tire skeleton 10. The difference between the maximum thickness and the minimum thickness of the tire skeleton 10 from the maximum bending portion in 14 to the maximum bending portion in the other side portion is 0.1 mm or less, and the tire skeleton 10 in the side portion 14 The thickness D1 of the maximum bent portion of the side rubber layer 24 is 0.5 mm or more and 2.5 mm or less, the thickness D2 of the maximum bent portion of the side rubber layer 24 is more than 1.0 mm and 5.0 mm or less, and the tire skeleton 10 and the coating Of the total thickness of the rubber layer 22 and the side rubber layer 24, the gas permeability of the portion having the minimum thickness D3 is 18 × 10-14 mol / (m2 · s · Pa) or less. [Selection diagram] Fig. 1

Description

  The present invention relates to a tire.

BACKGROUND ART In recent years, development of a tire having a skeleton formed of a resin material (hereinafter, also referred to as a tire skeleton) has been promoted for reasons of weight reduction, easiness of molding, easiness of recycling, and the like. As an attempt to improve the durability of such a tire, a method of reinforcing a tire frame body using a reinforcing cord has been proposed.
For example, Patent Document 1 proposes a method of winding a reinforcing cord member in a circumferential direction around an outer peripheral portion of a resin-made tire frame body.

JP 2012-46030 A

  The tire described in Patent Document 1 is improved in running durability as compared with a conventional tire, but in the performance required for the tire, further improvement in the durability is desired. In addition, from the viewpoint of weight reduction and cost, it is desirable that the thickness of the tire frame is thin, but if the thickness is reduced, the gas barrier properties against air etc. are likely to decrease, and after the rubber material is vulcanized May be deformed. On the other hand, if the thickness is increased, the running durability is likely to be reduced.

  An object of the present invention is to provide a tire having improved gas barrier properties, resistance to deformation due to heating, and running durability while suppressing the overall thickness, weight and cost.

[1] A pair of bead portions, a pair of side portions extending from the bead portions to the outer side in the tire radial direction, and a crown portion connected to the inner side in the tire width direction of the side portions
An annular tire frame body including a resin material;
A coated rubber layer containing rubber and disposed on at least the side portion of the tire frame body;
A rubber including a side rubber layer disposed on the side portion of the tire frame via the covering rubber layer;
The difference between the maximum thickness of the tire frame and the minimum thickness of the tire frame from the maximum bend in one side portion of the tire frame to the maximum bend in the other side is 0.1 mm or less.
In the side portion, the thickness D1 of the maximum bending portion of the tire frame is 0.5 mm or more and 2.5 mm or less, and the thickness D2 of the maximum bending portion of the side rubber layer is more than 1.0 mm and 5.0 mm or less Among the total thickness of the tire frame body, the covering rubber layer, and the side rubber layer, the gas permeability of the minimum thickness D3 portion is 18 × 10 ^-14 mol / (m ² · s · Pa) or less ,tire.
[2] The tire according to [1], wherein the resin material contains 50% by mass or more of a polyamide-based thermoplastic elastomer.
[3] The tire according to [1] or [2], wherein the gas permeability of the portion consisting of the covering rubber layer and the side rubber layer in the portion of the minimum thickness D3 is equal to or less than the gas permeability of the tire frame. .
[4] The tire according to any one of [1] to [3], wherein the thickness D1 is 1.0 mm or more and 2.4 mm or less.

  According to the present invention, it is possible to provide a tire having improved gas barrier properties, deformation resistance to heating, and running durability while suppressing the overall thickness, weight, and cost.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing along the tire width direction which shows the structure of the tire which concerns on one Embodiment of this invention. It is an expanded sectional view of a bead part and a side part of a tire shown in FIG. It is a graph which shows the relationship between the gas permeability in the thinnest part of a side part, and the thickness of a tire frame body.

  Hereinafter, although specific embodiments of the present invention will be described in detail, the present invention is not limited to the following embodiments at all, and can be implemented with appropriate modifications within the scope of the object of the present invention. be able to.

In the present specification, the term "bead portion" refers to the tire radial direction inner end to 30% of the tire cross-sectional height. "Side" means from the bead to the end of the crown. Here, “end of crown” means that the tire is mounted on the standard rim specified in JATMA YEAR BOOK (2014 edition, Japan Automobile Tire Association Standard), and the application size / ply rating in JATMA YEAR BOOK 100% of the air pressure (maximum air pressure) corresponding to the maximum load capacity (bold load in the internal pressure-load capacity correspondence table) is filled as an internal pressure, and indicates the outermost contact portion in the tire width direction when the maximum load capacity is loaded. If TRA standard or ETRTO standard is applied at the place of use or production site, follow each standard.
Here, FIG. 1 shows a cross-sectional view along the tire width direction showing the structure of a tire according to an embodiment of the present invention. In the tire 100 shown in FIG. 1, the bead portion corresponds to 12, the side portion 14, and the crown portion 16. Details will be described later.
Further, in the present specification, “resin” is a concept including thermoplastic resin and thermosetting resin, but does not include vulcanized rubber such as natural rubber and synthetic rubber.
Although "rubber" is a high molecular compound which has elasticity, it distinguishes it from a thermoplastic resin elastomer in this specification.
"Thermoplastic resin" refers to a polymer compound which softens as temperature rises and which becomes relatively hard and strong when cooled, and is a concept including a thermoplastic elastomer. The “thermoplastic resin elastomer” is a polymer compound having elasticity, and a crystalline, high melting point hard segment or a polymer constituting a high cohesive hard segment, and an amorphous, low glass transition temperature It means a thermoplastic resin having a polymer constituting a soft segment.
In the thermoplastic resin elastomer, the hard segment acts as a pseudo crosslinking point and develops elasticity (so-called physical crosslinking). On the other hand, rubber has a double bond or the like in its molecular chain, and by adding sulfur or the like to crosslink (vulcanize), it forms a three-dimensional network structure and develops elasticity (chemical crosslinking) . For this reason, the thermoplastic resin elastomer melts the hard segment by heating and cools again to form a pseudo crosslinking point again.
Moreover, the numerical range represented using "-" in this specification means the range which includes the numerical value described before and after "-" as a lower limit and an upper limit.
In addition, the term "process" is included in the term if the intended purpose of the process is achieved, even if it is not only an independent process but can not be clearly distinguished from other processes.

[tire]
The tire according to the present invention comprises a pair of bead portions, a pair of side portions extending from the bead portions to the outer side in the tire radial direction, and a crown portion connected to the inner side in the tire width direction of the side portions.
An annular tire frame body including a resin material;
A coated rubber layer containing rubber and disposed on at least the side portion of the tire frame body;
And a side rubber layer disposed on the side portion of the tire frame via the covering rubber layer.
Furthermore, the tire of the present invention satisfies the following conditions 1 to 4.
Condition 1: The difference between the maximum thickness and the minimum thickness of the tire frame from the maximum bend in one side of the tire frame to the maximum bend in the other side (hereinafter referred to as “tire frame” The difference between the maximum thickness and the minimum thickness between the maximum bending portions), which is also referred to as “a difference between 0.1 mm and less.
Condition 2: The thickness D1 of the maximum bending portion at the side portion of the tire frame is 0.5 mm or more and 2.5 mm or less.
Condition 3: The thickness D2 of the maximum bending portion of the side rubber layer is more than 1.0 mm and not more than 5.0 mm.
Condition 4: In the side portion, the gas permeability of the minimum thickness D3 portion of the total thickness of the tire frame, the covering rubber layer, and the side rubber layer is 18 × 10 ^-14 mol / (m ² · s · Pa) or less is there.

Here, the maximum bending portion refers to a portion where the tire is bent and the amount of deformation thereof is maximized in a state where the internal pressure is a standard air pressure by being assembled to a standard rim of JATMA standard.
The determination of the maximum bending portion is performed by the following method. In the side portion of the cross section in the tire width direction, a group of areas at a constant interval obtained by dividing the inner peripheral surface (outline) of the tire frame by 0.5 cm is specified, and the radius of curvature in each area is measured. Of the measured radii of curvature, the portion with the smallest radius of curvature is taken as the maximum bending portion of the tire frame (the inner circumferential side of the tire frame).
The thickness D1 of the maximum bending portion of the tire frame is a distance between the inner circumferential surface and the outer circumferential surface of the tire frame measured on a normal line perpendicular to a tangent passing through the maximum bending portion of the tire frame Do.
The thickness D2 of the maximum bending portion of the side rubber layer is the distance between the inner circumferential surface and the outer circumferential surface of the side rubber layer measured on the normal line perpendicular to the tangent passing through the maximum bending portion of the tire frame.
The thickness D1 of the maximum bending portion and the thickness D2 of the maximum bending portion can be measured by a known method. Specifically, measurement can be performed using a scale in a tire cross section obtained by cutting in the tire width direction.

In the tire skeleton, the covering rubber layer, and the total thickness of the side rubber layer, the portion having the minimum thickness D3 is a tire skeleton which is assembled in a standard rim of the JATMA standard and measured with the internal pressure as the standard air pressure Of the total thickness of the rubber layer and the side rubber layer, a portion where the total thickness is the smallest (hereinafter, also referred to as "the thinnest portion of the side portion").
Identification of the thinnest part of the side part (that is, the part of the minimum thickness D3) is performed by the following method.
The above-mentioned total thickness is measured at intervals of 0.5 cm along the inner peripheral surface (outline) of the tire frame body at the side portion of the cross section in the tire width direction. Of the total thickness measured, the portion where the total thickness is the smallest is taken as the thinnest portion of the side portion. The total thickness and the thickness of the minimum thickness D3 can be measured by the same method as the thickness D1 of the maximum bending portion and the thickness D2 of the maximum bending portion.

Moreover, the gas permeability in the thinnest part of the side part is measured by the following method.
A test piece having the same laminated structure as the laminated structure of the thinnest part (tire frame body, coated rubber layer and side rubber layer) is prepared, and using the test piece, JIS K 7126-1: 2006 (Part 1: difference) Pressure measurement).
In addition, the gas permeability of the tire frame, the gas permeability of the coated rubber layer, the gas permeability of the side rubber layer, and the gas permeability of the coated rubber layer and the side rubber layer are test pieces having the same structure as each structure. It can produce and it can measure by the method similar to the above using the test piece. The same applies to the case where the tire frame body has an inner rubber layer.

  Here, a tire having a tire skeleton including a resin skeleton (hereinafter, also referred to as a resin skeleton) is compared with a conventional tire having a skeleton formed of rubber (hereinafter, also referred to as a "rubber skeleton"). The improvement of fuel performance by weight reduction and the improvement of recyclability are expected. On the other hand, since it is necessary to use a high-performance resin material in order to produce a resin skeleton satisfying the running durability and the like required as a tire, the manufacturing cost is increased. As a method for suppressing the manufacturing cost, there is a method of reducing the amount of resin used. Specifically, a method of using a blend material of rubber and resin for the skeleton, and a method of reducing the thickness of the skeleton may be mentioned. However, the former method tends to lower the bending durability of the tire. Further, in the latter method, the gas barrier properties are easily lowered as compared with the rubber skeleton because the thickness of the skeleton is reduced, and the skeleton may be deformed after the rubber material is vulcanized. If the thickness is increased to improve the gas barrier properties and the deformation of the framework, the running durability tends to be reduced. In addition, since resin materials having enhanced gas barrier properties generally tend to have high elastic modulus, they are easily broken when a mechanical force is applied.

On the other hand, in the tire according to the present invention, the difference between the maximum thickness and the minimum thickness between the maximum bending portions of the tire framework (condition 1), the thickness D1 of the maximum bending portions of the tire framework (condition 2), the side rubber layer The thickness D2 (condition 3) of the largest bent portion and the gas permeability (condition 4) at the thinnest portion of the side portion are adjusted in appropriate ranges.
As a result, even if the thickness and weight of the entire tire are kept relatively small, the permeation of air from the inside of the tire is suppressed, and even after the rubber material is vulcanized, the skeleton becomes difficult to deform, and further the durability at the time of running the tire Also improves the quality.
That is, according to the present invention, it is possible to realize a tire having improved gas barrier properties, deformation resistance to heating, and running durability while suppressing the overall thickness, weight, and cost.

  Here, the above conditions 1 to 4 are preferably in the following ranges from the viewpoint of improving the gas barrier properties, the deformation resistance to heating, and the running durability.

-Condition 1-
The difference between the maximum thickness and the minimum thickness between the maximum bending portions of the tire frame is 0.1 mm or less, preferably 0.05 mm or less, and more preferably 0.03 mm or less.
Here, that the said difference is 0.1 mm or less means that there is substantially no difference.
That is, the tire frame body is formed in a state (approximately the same thickness) in which the thickness between the maximum bending portions is nearly uniform.
When the difference is 0.1 mm or less, the tire is easily pressurized uniformly, so that defects such as deformation are less likely to occur in tire molding. In addition, the center of the circle becomes infinitely central, and blurring hardly occurs. Thereby, the tire durability can be easily improved.

-Condition 2-
The thickness D1 of the maximum bending portion at the side portion of the tire frame is 0.5 mm or more and 2.5 mm or less, preferably 0.8 mm or more and 2.5 mm or less, and more preferably 1.0 mm or more and 2.4 mm or less is there.
When the thickness D1 of the maximum bending portion is 0.5 mm or more, handle response, gas barrier properties, and cut resistance tend to be favorable.
When the thickness D1 of the maximum bending portion is 2.5 mm or less, it is easy to improve the air leakage due to the occurrence of the side crack. In addition, since the bending durability can be easily improved, the traveling distance can be improved. Furthermore, since the amount of resin can be reduced, the cost can be reduced.

-Condition 3-
The thickness D2 of the maximum bending portion of the side rubber layer is more than 1.0 mm and 5.0 mm or less, preferably 2.0 mm or more and 5.0 mm or less, and more preferably 2.5 mm or more and 4.5 mm or less.
By the thickness D2 of the largest bending part exceeding 1.0 mm, gas barrier property and cut resistance are easy to improve.
When the thickness D1 of the maximum bending portion is 5.0 mm or less, the weight can be reduced, so that the rolling resistance can be easily reduced.

-Condition 4-
In the side portion, of the total thickness of the tire frame body, the covering rubber layer, and the side rubber layer, the gas permeability at the minimum thickness D3 portion, that is, the thinnest portion of the side portion is 18 × 10 ^-14 mol / (m ² · S · Pa) or less, preferably 15 × 10 ^-14 mol / (m ² · s · Pa) or less, more preferably 10 × 10 ^-14 mol / (m ² · s · Pa) or less.
It is easy to hold | maintain an internal pressure because the said gas permeability is 18 * 10 < ^-14 > mol / (m < ² > * s * Pa) or less.

In the present invention, the gas permeability of the side rubber layer is preferably equal to or less than the gas permeability of the tire frame.
When the gas permeability of the tire frame is lower than the gas permeability of the side rubber layer, air transmitted from the inside of the tire tends to be accumulated at the interface between the tire frame and the rubber layer (side rubber layer and covering rubber layer). As a result, voids are easily formed at the interface, which leads to peeling of the interface and a reduction in adhesive strength.
When the gas permeability of the side rubber layer is equal to or less than the gas permeability of the tire frame, the gas transmitted from the inside of the tire is likely to be released to the outside due to the high internal pressure.
Therefore, by setting the gas permeability of the side rubber layer ≦ the gas permeability of the tire frame, the formation of voids at the interface is suppressed, and the peeling of the interface and the decrease in adhesive strength are suppressed.

As described above, the tire of the present invention at least includes the tire frame, the covering rubber layer, and the side rubber layer, and may have other layers as necessary. As another layer, the inner-rubber layer provided in the inner peripheral surface of a tire frame body, the contact bonding layer provided between each member and layers, etc. are mentioned, for example.
Hereinafter, each member and layer will be described in detail.

<< Tire frame body >>
The tire frame body in the present invention contains a resin material.
In the present invention, the "resin material" contains at least a thermoplastic resin and may contain other components such as additives.

  Examples of the thermoplastic resin include polyamide thermoplastic resins, polyester thermoplastic resins, olefin thermoplastic resins, polyurethane thermoplastic resins, vinyl chloride thermoplastic resins, polystyrene thermoplastic resins and the like. it can. You may use these individually or in combination of 2 or more types. Among these, polyamide-based thermoplastic resins, polyester-based thermoplastic resins, and olefin-based thermoplastic resins are preferable, and polyamide-based thermoplastic resins and olefin-based thermoplastic resins are more preferable.

As the thermoplastic elastomer, for example, polyamide-based thermoplastic elastomer (TPA), polystyrene-based thermoplastic elastomer (TPS), polyurethane-based thermoplastic elastomer (TPU), polyolefin-based thermoplastic elastomer (TPO) defined in JIS K6418, Examples include polyester-based thermoplastic elastomer (TPEE), crosslinked thermoplastic rubber (TPV), and other thermoplastic elastomers (TPZ). In view of the elasticity required during traveling, the moldability at the time of production, etc., it is preferable to use a thermoplastic resin as the resin material, and it is more preferable to use a thermoplastic elastomer, and a polyamide thermoplastic elastomer It is particularly preferred to use (TPA).
When the resin material contains a polyamide-based thermoplastic elastomer, the resin material preferably contains 50% by mass or more, more preferably 65% by mass or more, of the polyamide-based thermoplastic elastomer with respect to the total amount of the resin material. It is particularly preferable to include at least% by mass.
When the resin material contains 50% by mass or more of the polyamide-based thermoplastic elastomer, the weight of the tire can be reduced and rolling resistance can be easily reduced.

  Hereinafter, as an example of the thermoplastic resin contained in the resin material, a polyamide-based thermoplastic elastomer and a polyolefin-based thermoplastic elastomer will be described.

<Polyamide-based thermoplastic elastomer>
The polyamide-based thermoplastic elastomer is a thermoplastic elastomer comprising a copolymer having a crystalline, high melting point hard segment-constituting polymer and a non-crystalline, low glass transition temperature soft segment-constituting polymer, It means one having an amide bond (-CONH-) in the main chain of the polymer constituting the hard segment.

-Hard segment-
Examples of the polyamide forming the hard segment (polymer compound forming the hard segment) include polyamides synthesized using a monomer represented by the following general formula (1) or (2) .

In general formula (1), R ¹ represents a hydrocarbon chain of 2 to 20 carbon atoms. As a molecular chain of C2-C20 hydrocarbon, a C2-C20 alkylene group is mentioned, for example.

In formula (2), R ² represents a hydrocarbon chain of 3 to 20 carbon atoms. As a molecular chain of C3-C20 hydrocarbon, a C3-C20 alkylene group is mentioned, for example.

  As a monomer represented by the said General formula (1) or General formula (2), (omega) -amino carboxylic acid and lactam are mentioned. Moreover, as polyamide which forms the said hard segment, the polycondensate of these (omega)-amino carboxylic acids and lactams, the co-condensation polymer of diamine and dicarboxylic acid, etc. are mentioned.

  Examples of the polyamide forming the hard segment include polyamides obtained by ring-opening polycondensation of ε-caprolactam (polyamide 6), polyamides obtained by ring-opening polycondensation of undecane lactam (polyamide 11), and polyamides obtained by ring-opening polycondensation of lauryl lactam 12) Polyamide (polyamide 12) obtained by polycondensing 12-aminododecanoic acid, Polycondensed polyamide of diamine and dibasic acid (polyamide 66) or polyamide (amide MX) having meta-xylene diamine as a constitutional unit Can.

  Moreover, amide MX which has metaxylene diamine as a structural unit can be represented, for example, by the following structural unit (A-1) [in (A-1), n represents the number of arbitrary repeating units], for example, As n, 2-100 are preferable and 3-50 are still more preferable.

  The number average molecular weight of the polymer (polyamide) forming the hard segment is preferably 300 or more and 15,000 or less from the viewpoint of melt moldability, toughness, and low temperature flexibility.

-Soft segment-
Examples of the polymer forming the soft segment (polymer compound forming the soft segment) include polyester and polyether, and further, for example, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol (PTMG), ABA type triblock polyether etc. are mentioned, These can be used individually or in 2 or more types.

  In addition, the polymer forming the soft segment may have a functional group introduced at the end. The said functional group should just react with the terminal group of the compound (The polymer which forms a hard segment, a chain extender, etc.) made to react with the polymer which forms a soft segment. For example, when the terminal group of the compound to be reacted with the polymer forming the soft segment is a carboxy group, examples of the functional group include an amino group.

Among polymers forming a soft segment, those having an amino group introduced at the end include, for example, polyether diamine in which ammonia etc. is reacted at the end of polyether, etc. Specifically, ABA-type triblock poly Ether diamine etc. are mentioned.
Here, examples of the “ABA triblock polyether” include polyethers represented by the following general formula (3).

  In General Formula (3), x and z each independently represent an integer of 1 to 20. y represents an integer of 4 to 50.

  Moreover, the "ABA type triblock polyether diamine" can mention the polyether diamine shown by the following general formula (N).

In general formula (N), X _N and Z _N each independently represent an integer of 1 to 20. Y _N represents an integer of 4 to 50.

  The number average molecular weight of the polymer forming the soft segment is preferably 200 or more and 6000 or less, more preferably 400 or more and 4000 or less, and particularly preferably 600 or more and 2000 or less from the viewpoint of toughness and low temperature flexibility.

-Joint-
As described above, as the bonding portion of the polyamide-based thermoplastic elastomer, for example, a portion bonded by a chain extender is mentioned.
Examples of the chain extender include dicarboxylic acids, diols, and diisocyanates. As the dicarboxylic acid, for example, at least one selected from aliphatic, alicyclic and aromatic dicarboxylic acids or derivatives thereof can be used. Examples of the diol include aliphatic diols, alicyclic diols and aromatic diols. As said diisocyanate, aromatic diisocyanate, aliphatic diisocyanate, alicyclic diisocyanate, and these mixtures can be used, for example.

-Molecular weight-
The number average molecular weight of the polyamide-based thermoplastic elastomer is, for example, 15,700 to 200,000. When the number average molecular weight of the polyamide-based thermoplastic elastomer is less than 15,700, the rim assembling property may be reduced. In addition, when the number average molecular weight of the polyamide thermoplastic elastomer exceeds 200,000, the melt viscosity becomes high, and it is necessary to increase the molding temperature and the mold temperature in order to prevent the insufficient filling at the time of forming the tire frame. There may be. In that case, since the cycle time becomes long, the productivity is inferior.

  The number average molecular weight of the polyamide thermoplastic elastomer is preferably 20,000 to 160,000. The number average molecular weight of the polyamide-based thermoplastic elastomer can be measured by gel permeation chromatography (GPC), for example, GPC (gel permeation chromatography) such as “HLC-8320 GPC EcoSEC” manufactured by Tosoh Corporation. It can be used. The same applies to the measurement of the number average molecular weight of other thermoplastic elastomers described later.

In the polyamide-based thermoplastic elastomer, the ratio (x / y) of the mass (x) of the hard segment to the mass (y) of the soft segment makes it possible to secure the rigidity as a tire and to make a rim assembly possible. 30 / 70-80 / 20 are preferable, and 50 / 50-75 / 25 are still more preferable.
When the chain extender is used, its content is such that the terminal functional group (for example, hydroxyl group or amino group) of the polymer forming the soft segment and the carboxyl group of the chain extender are approximately equimolar. It is preferable to be set to

-Manufacturing method-
The polyamide-based thermoplastic elastomer can be synthesized by copolymerizing the polymer forming the hard segment and the polymer forming the soft segment by a known method.
For example, the polyamide-based thermoplastic elastomer is composed of a monomer constituting a hard segment (for example, ω-aminocarboxylic acid such as 12-aminododecanoic acid or a lactam such as lauryl lactam) and a chain extender (for example, adipic acid or After polymerizing dodecanedicarboxylic acid) in a container, a polymer (for example, polypropylene glycol, ABA type triblock polyether, diamine whose terminal is modified to an amino group, etc.) constituting a soft segment is added, It can be obtained by further polymerizing.

  In particular, when ω-aminocarboxylic acid is used as a monomer constituting the hard segment, it can be synthesized by performing pressureless melt polymerization in addition to normal pressure melt polymerization or normal pressure melt polymerization. When a lactam is used as a monomer constituting the hard segment, an appropriate amount of water can be coexistent, and from melt polymerization under pressure of 0.1 MPa to 5 MPa and subsequent ordinary pressure melt polymerization and / or reduced pressure melt polymerization. Can be manufactured in the following manner. In addition, these synthesis reactions can be carried out either batchwise or continuously. In addition, for the above-mentioned synthesis reaction, a batch reaction kettle, a single tank system or a multi-tank continuous reaction apparatus, a tubular continuous reaction apparatus or the like may be used alone or in combination as appropriate.

<Polyolefin-based thermoplastic resin elastomer>
The polyolefin-based thermoplastic resin elastomer is at least a polyolefin having a crystalline and high melting point hard segment, and other polymers (for example, other polyolefins, polyvinyl compounds and the like) are noncrystalline and have a low glass transition temperature soft segment. It means a material that is being configured, and examples include polyolefin-based thermoplastic resin elastomer (TPO) defined in JIS K6418: 2007.

-Hard segment, soft segment-
As a polyolefin which forms a hard segment, polyethylene, a polypropylene, an isotactic polypropylene, a polybutene etc. are mentioned, for example.
As a polymer which forms a soft segment, although a polyolefin and a polyvinyl compound are mentioned, you may use ethylene propylene rubbers, such as EPM and EPDM, as a soft segment, for example.

Examples of polyolefin-based thermoplastic resin elastomers include olefin-α-olefin random copolymers and olefin block copolymers. For example, propylene block copolymers, ethylene-propylene copolymers, propylene-1-hexene copolymer Polymer, propylene-4-methyl-1-pentene copolymer, propylene-1-butene copolymer, ethylene-1-hexene copolymer, ethylene-4-methyl-pentene copolymer, ethylene-1-butene copolymer Polymer, 1-butene-1-hexene copolymer, 1-butene-4-methyl-pentene, ethylene-methacrylic acid copolymer, ethylene-methyl methacrylate copolymer, ethylene-ethyl methacrylate copolymer, Ethylene-butyl methacrylate copolymer, ethylene-methyl acrylate copolymer, air Ren-ethyl acrylate copolymer, ethylene-butyl acrylate copolymer, propylene-methacrylic acid copolymer, propylene-methyl methacrylate copolymer, propylene-ethyl methacrylate copolymer, propylene-butyl methacrylate copolymer And propylene-methyl acrylate copolymer, propylene-ethyl acrylate copolymer, propylene-butyl acrylate copolymer, ethylene-vinyl acetate copolymer, propylene-vinyl acetate copolymer and the like.
As for the polyolefin content rate in the said polyolefin-type thermoplastic resin elastomer, 50 mass% or more and 100 mass% or less are preferable.

As a polyolefin-type thermoplastic resin elastomer, the polyolefin-type thermoplastic resin elastomer (acid-modified polyolefin-type thermoplastic resin elastomer) which has an acidic group can also be used, for example.
Here, "acid modification" refers to bonding an unsaturated compound having an acidic group such as a carboxylic acid group, a sulfuric acid group or a phosphoric acid group to an olefin-based thermoplastic resin elastomer. For example, when an unsaturated carboxylic acid (generally, maleic anhydride) is used as the unsaturated compound having an acidic group, the olefinic thermoplastic resin elastomer is bonded to the unsaturated bond site of the unsaturated carboxylic acid (for example, , Graft polymerization).

-Molecular weight-
The number average molecular weight of the polyolefin-based thermoplastic resin elastomer is preferably 5,000 to 10,000,000. When the number average molecular weight of the polyolefin-based thermoplastic resin elastomer is 5,000 to 10,000,000, the mechanical properties of the thermoplastic resin material are sufficient, and the processability is also excellent. From the same viewpoint, the number average molecular weight of the polyolefin-based thermoplastic resin elastomer is more preferably 7,000 to 1,000,000, and particularly preferably 10,000 to 1,000,000.

  The mass ratio (x: y) of the hard segment (x) to the soft segment (y) in the polyolefin thermoplastic resin elastomer is preferably 50:50 to 95: 5 from the viewpoint of moldability, and 50:50. -90: 10 is more preferred.

-Manufacturing method-
The polyolefin-based thermoplastic resin elastomer can be synthesized by copolymerizing by a known method.

  The acid modification of the polyolefin-based thermoplastic resin elastomer is carried out, for example, using a twin-screw extruder or the like, using an olefin-based thermoplastic resin elastomer, an unsaturated compound having an acidic group (for example, unsaturated carboxylic acid) and an organic peroxide. It can be carried out by kneading and graft copolymerization. The addition amount of the unsaturated compound having an acidic group is preferably 0.1 parts by mass to 20 parts by mass, and more preferably 0.5 parts by mass to 10 parts by mass with respect to 100 parts by mass of the olefin-based thermoplastic resin elastomer .

<Other additives>
The tire frame body includes various fillers (for example, silica, calcium carbonate, clay), anti-aging agents, vulcanizing agents, vulcanization accelerators, metal oxides, process oils, plasticizers, etc., depending on the materials used. Various additives such as a colorant, a weathering agent, and a reinforcing material may be contained. There is no particular limitation on the content of the additive in the resin material (tire frame), and the additive can be appropriately used within the range that does not impair the effects of the present invention.

  As an antiaging agent, the antiaging agent as described in international publication WO2005 / 063482 is mentioned, for example. Specifically, for example, naphthylamines such as phenyl-2-naphthylamine and phenyl-1-naphthylamine, 4,4′-α, α-dimethylbenzyl) diphenylamine, p- (P-toluenesulfonylamide) -diphenylamine and the like Amine based antioxidants such as p-phenylenediamines such as diphenylamines, N, N'-diphenyl-p-phenylenediamine, N-isopropyl-N'-phenyl-p-phenylenediamine, etc., derivatives or mixtures thereof, etc. Can be mentioned.

  As the vulcanizing agent, known vulcanizing agents such as sulfur, organic peroxides, resin vulcanizing agents and the like can be used. Examples of the vulcanization accelerator include known vulcanization accelerators such as aldehydes, ammonias, amines, guanidines, thioureas, thiazoles, sulfenamides, thiurams, dithiocarbamates, xanthates and the like. It can be used. Examples of the fatty acids include stearic acid, palmitic acid, myristic acid, lauric acid and the like, and they may be blended in the form of a salt like zinc stearate. Among these, stearic acid is preferred. Further, examples of the metal oxide include zinc oxide (ZnO), iron oxide, magnesium oxide and the like, and among them, zinc oxide is preferable. The process oil may be any of aromatic, naphthenic and paraffinic oils.

<Physical properties of resin material contained in tire frame>
The melting point (or softening point) of the resin material is usually about 100 ° C. to 350 ° C., preferably about 100 ° C. to 250 ° C., but preferably about 120 ° C. to 250 ° C. from the viewpoint of tire productivity. 200 ° C. is more preferred.
Thus, by using a resin material having a melting point of 120 ° C. to 250 ° C., for example, when forming a skeleton of a tire by fusing the divided bodies (framework pieces), the periphery of 120 ° C. to 250 ° C. Even in the frame body fused in the temperature range, the adhesive strength between the tire frame pieces is sufficient. For this reason, the tire of the present invention is excellent in durability at the time of traveling, such as puncture resistance and abrasion resistance. The heating temperature is preferably 10 ° C. to 150 ° C. higher than the melting point (or softening point) of the resin material forming the tire frame piece, and more preferably 10 ° C. to 100 ° C. higher.

  The tensile yield strength defined in JIS K7113: 1995 of the resin material is preferably 5 MPa or more, preferably 5 MPa to 20 MPa, and more preferably 5 MPa to 17 MPa. When the tensile yield strength of the resin material is 5 MPa or more, it is possible to withstand the deformation due to the load applied to the tire when traveling or the like.

  10% or more is preferable, 10%-70% of the tensile yield elongation prescribed | regulated to JISK7113: 1995 of a resin material is preferable, and 15%-60% is more preferable. When the tensile yield elongation of the resin material is 10% or more, the elastic region is large, and the rim assembly property can be improved.

  The tensile elongation at break defined in JIS K7113: 1995 of the resin material is preferably 50% or more, preferably 100% or more, more preferably 150% or more, and particularly preferably 200% or more. When the tensile breaking elongation of the resin material is 50% or more, the rim assembling property is good, and it is possible to make it difficult to be broken against a collision.

  The deflection temperature under load (at 0.45 MPa load) specified in ISO 75-2 or ASTM D 648 of the resin material is preferably 50 ° C. or higher, preferably 50 ° C. to 150 ° C., and more preferably 50 ° C. to 130 ° C. Even if it is a case where vulcanization is performed in manufacture of a tire as load deflection temperature of resin material is 50 ° C or more, modification of a tire frame can be controlled.

  The tensile modulus of elasticity of the resin material is preferably 100 MPa to 500 MPa, more preferably 200 MPa to 400 MPa, and particularly preferably 200 MPa to 350 MPa, from the viewpoint of rim assembly property and internal pressure retention property.

<< Covered rubber layer >>
The tire of the present invention has a coated rubber layer. In the present invention, the "coated rubber layer" refers to a layer that contains rubber and is disposed on the outer peripheral surface of at least the side portion of the tire frame body. The covering rubber layer may be, for example, a layer covering the outer peripheral surface of the tire frame from one bead portion to the other bead portion.
The rubber contained in the coated rubber layer is not particularly limited. For example, natural rubber (NR); polyisoprene synthetic rubber (IR), polybutadiene rubber (BR), styrene-butadiene copolymer rubber (SBR), acrylonitrile butadiene Conjugated diene-based synthetic rubbers such as rubber (NBR), chloroprene rubber (CR) and butyl rubber (IIR); ethylene-propylene copolymer rubber (EPM); ethylene-propylene-diene copolymer rubber (EPDM); polysiloxane rubber And the like, and these may be used alone or in combination of two or more. Among these, natural rubber (NR) and a mixture of a natural rubber and a styrene-butadiene copolymer rubber (SBR / NR) are preferable from the viewpoint of adhesion to the adhesive layer.
Also, the coated rubber layer may comprise, for example, a plurality of reinforcing cords coated with rubber. As the reinforcing cords, steel cords, monofilaments (single wires) such as metal fibers or organic fibers, or multifilaments (twisted wires) obtained by twisting these fibers can be used.
In addition, the coated rubber layer may contain at least rubber, and may be formed of a rubber composition in which other components such as additives are added to the rubber depending on the purpose.
Examples of additives include reinforcing materials such as carbon black, fillers, vulcanizing agents, vulcanization accelerators, fatty acids or salts thereof, metal oxides, process oils, antiaging agents, etc. can do.

Side rubber layer
The tire of the present invention has a side rubber layer. In the present invention, the “side rubber layer” refers to a layer that contains rubber and is disposed radially outward of the tire frame via the covering rubber layer.
As the rubber contained in the side rubber layer, the same kind of rubber as the rubber contained in the covering rubber layer can be used.

«Other layers»
As described above, the tire according to the present invention may have other layers such as an inner rubber layer, an adhesive layer, etc. in addition to the tire frame body, the covering rubber layer, and the side rubber layer.
The “inner rubber layer” refers to a layer that contains rubber and is disposed on at least a part of the inner circumferential surface of the tire frame. The inner rubber layer may be, for example, a layer covering the inner circumferential surface of the tire frame from one bead portion to the other bead portion.
As rubber | gum contained in an inner rubber layer, rubber | gum same as the rubber | gum contained in a coating rubber layer can be used. In addition, the inner rubber layer may be provided with a plurality of reinforcing cords covered with rubber as in the case of the coated rubber layer.

  Each member and layer may be fixed by an adhesive layer. The material of the adhesive layer is not particularly limited as long as each member and layer can be adhered. For example, the adhesive layer can be formed using an adhesive, and an aqueous dispersion adhesive, a solventless adhesive, a solution adhesive or a solid adhesive (for example, a hot melt adhesive) or the like is used. be able to.

Hereinafter, an embodiment is given and one embodiment of the present invention is described. In the drawings, arrow W indicates the tire axial direction (tire width direction), and arrow S indicates the tire radial direction extending in the radial direction of the tire from the tire axis (not shown). Moreover, the dashed-dotted line CL has shown the tire equatorial plane.
FIG. 1 is a cross-sectional view along the tire width direction showing the structure of a tire according to the present embodiment, and FIG. 2 is an enlarged cross-sectional view of a bead portion and a side portion of the tire shown in FIG.

As shown in FIG. 1, the tire 100 of the present embodiment includes an annular tire frame body 10. The tire frame body 10 includes a pair of bead portions 12, a pair of side portions 14 extending outward from the bead portions 12 in the tire width direction, and a crown portion 16 connected to the tire width direction inner side of the side portions 14. A tread member 30 is disposed in the crown portion 16. The tire 100 is assembled to the rim 20.
In the present embodiment, a case where the tire frame body 10 is formed of a thermoplastic resin will be described.

  The tire frame body 10 is a tire of a tire, in which ring-shaped tire frame halves 10A of the same shape, in which one bead portion 12, one side portion 14 and a crown portion 16 having a half width are integrally formed, face each other. It is formed by joining at the equatorial plane CL. For joining at the tire equatorial plane CL, a welding thermoplastic material (not shown) is used. The tire frame body 10 is not limited to one formed by joining two members, and may be formed by joining three or more members, and the pair of bead portions 12, the pair of side portions 14, and The crown portion 16 may be integrally formed.

  The tire skeleton half 10A formed using a thermoplastic material can be formed by, for example, vacuum forming, pressure forming, injection molding (injection molding), melt casting, etc., and in the case of molding (vulcanization) with rubber As compared with the above, the manufacturing process can be greatly simplified and the molding time can be shortened. Even if the tire frame body 10 is made of a single thermoplastic material, each portion of the tire frame body 10 (the side portion 14 and the crown portion 16) as in the case of a conventional rubber-made pneumatic tire. , Bead 12 etc.) may be used.

  A bead core 18 is embedded in the bead portion 12 of the tire frame body 10. The bead core 18 is made of a steel cord similar to a conventional general pneumatic tire. In addition, the rigidity of the bead part 12 is ensured, and if there is no problem in fitting with the rim 20, the bead core 18 may be omitted. Further, the bead core 18 may be formed of a cord other than steel, such as an organic fiber cord, a cord in which an organic fiber is resin-coated, or the bead core 18 is formed of a hard resin by injection molding instead of a cord. It may be

  A reinforcing cord layer 28 is disposed on the outer side in the tire radial direction of the crown portion 16 of the tire frame 10 through an adhesive layer (not shown) so as to make a round in the tire circumferential direction. The reinforcing cord layer 28 comprises a plurality of reinforcing cords 26. The reinforcing cord 26 is coated with a rubber material and is formed by being spirally wound in the tire circumferential direction. In other words, the reinforcing cord layer 28 is formed by spirally winding the reinforcing cord layer 28 formed by covering the reinforcing cord 26 with a rubber material in the tire circumferential direction.

A covering rubber layer 22 covering the outer peripheral surface of the tire frame 10 is disposed on the outer peripheral surface of the tire frame 10 from one bead portion 12 to the other bead portion 12 via the reinforcing cord layer 28. There is. The covering rubber layer 22 is provided with a plurality of reinforcing cords (not shown) covered with rubber.
A side rubber layer 24 is disposed on the side portion 14 of the tire frame 10 with the covering rubber layer 22 interposed therebetween.

  A tread member 30 is disposed on the tire radial direction outer side of the tire frame 10, the reinforcing cord layer 28, the covering rubber layer 22, and the side rubber layer 24 in the crown portion 16. The tread member 30 constitutes a tire tread which is a contact portion of the tire 100. The tread member 30 is formed of a rubber that is superior in wear resistance to the thermoplastic resin forming the tire frame 10. As the rubber used for the tread member 30, the same kind of rubber as the rubber used for the conventional rubber pneumatic tire can be used. Further, on the tread surface of the tread member 30, a drainage groove 30A extending in the tire circumferential direction is formed. Although two grooves 30A are formed in the present embodiment, the invention is not limited to this, and more grooves 30A may be formed. Moreover, a well-known thing is used as a tread pattern.

  In order to manufacture the tire 100 in the present embodiment, for example, after obtaining an annular tire frame 10, an adhesive is applied to the crown portion 16 of the tire frame 10 to form a coating (adhesive layer). An unvulcanized reinforcing cord layer 28 is formed on the coating film by spirally winding the reinforcing cord 26 coated with the unvulcanized rubber material in the circumferential direction of the tire. Next, the coated rubber layer 22 containing an unvulcanized rubber material and the side rubber layer 24 are formed, and the unvulcanized tread member 30 is placed on the crown portion. Thereafter, a curing process is performed by heating, whereby the reinforcing cord layer 28 having the reinforcing cords 26 on the tire frame 10, the coated rubber layer 22, the side rubber layer 24, and the tread member 30 are provided. The tire 100 can be obtained. In addition, the manufacturing method of the tire 100 in this embodiment is not limited to the said method.

(Action)
The operation of the tire 100 in the present embodiment will be described.
In the tire 100 of the present embodiment, the difference between the maximum thickness and the minimum thickness between the maximum bending portions of the tire frame 10, the thickness D1 of the maximum bending portions of the tire frame 10, and the thickness of the maximum bending portions of the side rubber layer 24. The gas permeability at D2 and the thinnest portion T of the side portion 14 is adjusted to the above-mentioned range.
Here, the maximum bending portion of the tire frame 10 corresponds to "10B" in FIG. 2, and the thickness D1 of the maximum bending portion corresponds to "D1" in FIG.
The maximum bending portion of the side rubber layer 24 corresponds to "24B" in FIG. 2, and the thickness D2 of the maximum bending portion corresponds to "D2" in FIG.
The minimum thickness D3 of the tire frame 10, the covering rubber layer 22 and the side rubber layer 24 corresponds to "D3" in FIG. 2, and the thinnest portion of the side portion 14 (that is, the portion of the minimum thickness D3) It corresponds to "T".
In the tire 100 of this embodiment, the difference between the maximum thickness and the minimum thickness, the thickness (D1, D2), and the gas permeability at the thinnest portion T are adjusted, so the thickness and weight of the entire tire are compared Even if it is suppressed to a very small size, the permeation of air from the inside of the tire is suppressed, the skeleton is less likely to be deformed even after the rubber material is vulcanized, and the durability during running of the tire can be further improved.
Moreover, since the tire frame body 10 of the tire 100 of the present embodiment is formed of a thermoplastic resin, the structure is simpler than that of a conventional rubber tire.

(Other embodiments)
Although an example of the embodiment of the present invention has been described, the present invention is not limited to the above embodiment, and various other embodiments are possible within the scope of the present invention.

For example, the tire according to the above-described embodiment may include an inner rubber layer disposed on the inner circumferential surface of the tire frame from, for example, one bead portion to the other bead portion.
In this case, the thickness of the tire frame body is a thickness including the thickness of the inner rubber layer. Moreover, the gas permeability in the thinnest part of the side part is taken as the gas permeability of the minimum thickness part of the total thickness of the tire frame including the inner rubber layer, the covering rubber layer and the side rubber layer.
When the tire according to the present embodiment includes the inner rubber layer, the durability at the time of running the tire can be further improved.

  Hereinafter, the present invention will be more specifically described using examples. However, the present invention is not limited to this.

  The tire having the structure shown in the above-described embodiment was manufactured by the same method as described above, and used as the tire of Example 1 to Example 9 and Comparative Example 1 to Comparative Example 3. In addition, the resin material shown in Table 4 was used as the resin material of each example. Details of each material are as follows.

(Material of tire frame)
The following resin materials were used.
TPA1 ... Polyamide-based thermoplastic elastomer ("UBEST AXPA 9055X1" manufactured by Ube Industries, gas permeability: 3 × 10 ^-16 mol · m / (m ² · s · Pa))
TPA2 ... Polyamide-based thermoplastic elastomer ("UBEST AXPA 9048 X1" manufactured by Ube Industries, gas permeability: 5 × 10 ^-16 mol · m / (m ² · s · Pa))
TPA3 ... Polyamide-based thermoplastic elastomer ("Pebax 5533 of Pebax Series" manufactured by Arkema, gas permeability: 5 × 10 ^-16 mol · m / (m ² · s · Pa))
TPA4 ... Polyamide-based thermoplastic elastomer ("PA6" manufactured by Ube Industries, gas permeability: 3 × 10 ^-16 mol · m / (m ² · s · Pa))

(Material of side rubber layer)
The compounded rubber (unvulcanized rubber) mixed in the composition of the following Table 1 was used as a material of the side rubber layer (hereinafter referred to as material A).
Separately, a sample piece of material A (length 100 mm × width 100 mm × thickness 1.0 mm) was obtained, and the rubber in material A was vulcanized. The gas permeability of the sample piece of the material A after vulcanization was measured by the method described above, and the gas permeability was 10 × 10 ^-16 mol · m / (m ² · s · Pa) .

In addition, the detail of each component in Table 1 is as follows.
Natural rubber (NR): RSS # 3
^※ 1 "150 L" made by Ube Industries, Ltd.
^※ 2 "Seast F" manufactured by Tokai Carbon Co., Ltd.
^※ 3 Micro-crystalline wax made by Nippon Seiwa Co., Ltd. "Ozo Ace 0701"
^* 4 Ouchi Shinko Chemical Co., Ltd. 6PPD "Nocrac 6C"
^※ 5 "Noccellar D" made by Ouchi Shinko Chemical Co., Ltd.
^※ 6 "Noccellar DM" made by Ouchi Shinko Chemical Co., Ltd.
^* 7 “Sunseller CM-G” manufactured by Sanshin Chemical Industry Co., Ltd.

(Material of coated rubber layer)
An organic fiber (PET fiber: multifilament) coated with a compounded rubber (unvulcanized rubber) obtained by mixing in the following Table 2 was used as a material of the coated rubber layer (hereinafter referred to as material B).
Separately, a sample piece of material B (length 100 mm × width 100 mm × thickness 1.0 mm) was obtained, and the rubber in material B was vulcanized. When the gas permeability of the sample piece of the material B after vulcanization was measured by the method described above, the gas permeability was 20 × 10 ^-16 mol · m / (m ² · s · Pa).

In addition, the detail of each component in Table 2 is as follows.
Natural rubber (NR): RSS # 3
* 1: Asahi Carbon Co., Ltd., trade name "Asahi # 70"
* 2: N- (1,3-Dimethylbutyl) -N'-phenyl-p-phenylenediamine, manufactured by Ouchi Emerging Chemical Industry Co., Ltd., trade name "NOCLAK 6C"

(Material of tread member)
The compounded rubber (unvulcanized rubber) mixed in the composition of Table 3 was used as the material of the tread member.

In addition, the detail of each component in Table 3 is as follows.
Natural rubber: RSS3
Styrene-Butadiene rubber: JSR 1500
Carbon black: "Seat 7HM" manufactured by N234 Tokai Carbon Co., Ltd.
Anti-aging agent: Sumitomo Chemical Co., Ltd. "Antigen 6C"
Vulcanization accelerator DPG: diphenyl guanidine vulcanization accelerator CZ: N-cyclohexylbenzothiazylsulfenamide

  The following measurement and evaluation were performed about the tire of each Example and a comparative example. The results are shown in Table 4.

[The difference between the maximum thickness and the minimum thickness between the maximum bending portions of the tire frame]
The difference between the maximum thickness and the minimum thickness between the maximum bends of the tire frame was measured. In Table 4, "maximum thickness-minimum thickness" represents the above difference.

[Thickness D1 of maximum bending portion, Thickness D2]
The thickness D1 of the maximum bending portion of the tire frame and the thickness D2 of the maximum bending portion of the side rubber layer were measured by the method described above. In addition, the thickness of the largest bending part of a coating rubber layer was also measured by the same method.

[Gas permeability]
The gas permeability in the thinnest part (tire frame, covering rubber layer and side rubber layer) of the side part; the gas permeability of the tire frame; and the gas permeability of the covering rubber layer and the side rubber layer were measured by the method described above. In addition, in Table 4, "tire frame body + coating rubber layer + side rubber layer" represents the gas permeability in the thinnest part (part of minimum thickness D3) of a side part.

[Evaluation of gas barrier properties (internal pressure retention characteristics)]
The tire of each example was assembled into a rim, and the tire was filled with air so that the internal pressure was 0.3 MPa. The obtained tire was left in a constant temperature and humidity chamber for 60 days in a state of being kept in an environment of 40 ° C./50% RH, and the internal pressure of the tire after leaving for 60 days was measured.
The gas barrier properties (internal pressure retention characteristics) of the tire were evaluated by calculating the internal pressure of the tire (the internal pressure of the tire / the internal pressure of the tire of Example 9) with respect to the internal pressure of the tire of Example 9.
(Standard)
A: Internal pressure ratio (internal pressure of tire / tire of Example 9) is equal to or higher than standard tire B: Internal pressure ratio (internal pressure of tire / tire of Example 9) is at acceptable level but slightly inferior to standard tire (within -25%)
C: As the internal pressure ratio (internal pressure of tire / tire of Example 9) becomes lower than the allowable level, it is inferior to the standard tire (more than minus 25%)

[Evaluation of resin deformation (resistance to heat deformation) after vulcanization]
After the rubber material was vulcanized (150 ° C., 35 minutes, pressure 3 atmosphere or less), the amount of deformation of the tire skeleton relative to the tire skeleton before vulcanization was measured to evaluate the presence or absence of deformation.
Specifically, the appearance was visually confirmed, and the presence or absence of the deformation was confirmed depending on whether or not the deformation was generated to such an extent as to allow visual recognition. The vulcanizing conditions were 1.5 best (1 best is T90 (minute) in Curast).

[Evaluation of void formation ability of tire frame / coated rubber layer interface]
After the rubber material was vulcanized (150 ° C., 35 minutes, pressure 3 atmosphere or less), the interface between the tire frame and the covering rubber layer was observed with a microscope to confirm the presence or absence of void formation.
Specifically, a cut sample of a tire was produced, and the presence or absence of void formation was confirmed by observing the interface between the tire frame and the coated rubber layer with a microscope.

[Evaluation of cut resistance]
The tire was rolled at a speed of 10 m / s at a prescribed internal pressure and prescribed load, and at that time, a blade-like cutter with a width of 500 mm and a height of 30 mm was stepped on. The depth of the cut in the tire was taken as the measure of cut resistance. In the index display where Comparative Example 3 is 100, it is shown that the larger the value, the better the result. Evaluation criteria are shown below.
(Standard)
A: cut resistance (index) of 80 or more B: cut resistance (index) of 60 to less than 80 C: cut resistance (index) of less than 60

[Evaluation of tire running durability]
Using a drum tester with a smooth drum surface and a diameter of 1.707 m, the ambient temperature is controlled to 30 ± 3 ° C, and failure occurs under the conditions of an internal pressure of 29.4 kPa and a load of 12.74 kN. The tires were run until the occurrence of The longer the traveling distance, the better the traveling durability.
As a result, the running durability of the tire of Comparative Example 1 is indicated by index as "100", that of less than 60 is "C", that of 60 or more and less than 100 is "B", and that of 100 or more is "A"".

FIG. 3 shows the relationship between the gas permeability in the thinnest part of the side part and the thickness of the tire frame.
As shown in FIG. 3, it is understood that Examples 1 to 9 are excellent in the gas barrier property because the gas permeability is smaller than Comparative Examples 1 and 2.
Further, as shown in Table 1, in Examples 1 to 9, no resin deformation occurred after vulcanization, and good results were obtained also in the evaluation of the tire running durability. On the other hand, in Comparative Example 3, although the gas permeability was small, the evaluation of running durability was “C”.
Moreover, the tires of Examples 1 to 9 are relatively lightweight because they have a resin skeleton, and the thickness of the tire skeleton and the thickness of the maximum bending portion of the side rubber layer are adjusted.
From the above results, it was found that the tires of Examples 1 to 9 have improved gas barrier properties, deformation resistance to heating, and running durability while suppressing the overall thickness, weight, and cost.

100 tire, 10 tire frame body, 10A tire frame half body, 12 bead portion, 14 side portion, 16 crown portion, 18 bead core, 20 rim, 22 coated rubber layer, 24 side rubber layer, 26 reinforcing cord, 28 reinforcing cord layer, 30 tread members, 30A grooves

Claims (4)

A pair of bead portions, a pair of side portions extending from the bead portions to the outer side in the tire radial direction, and a crown portion connected to the inner side in the tire width direction of the side portions;
An annular tire frame body including a resin material;
A coated rubber layer containing rubber and disposed on at least the side portion of the tire frame body;
A rubber including a side rubber layer disposed on the side portion of the tire frame via the covering rubber layer;
The difference between the maximum thickness of the tire frame and the minimum thickness of the tire frame from the maximum bend in one side portion of the tire frame to the maximum bend in the other side is 0.1 mm or less.
In the side portion, the thickness D1 of the maximum bending portion of the tire frame is 0.5 mm or more and 2.5 mm or less, and the thickness D2 of the maximum bending portion of the side rubber layer is more than 1.0 mm and 5.0 mm or less Among the total thickness of the tire frame body, the covering rubber layer, and the side rubber layer, the gas permeability of the minimum thickness D3 portion is 18 × 10 ^-14 mol / (m ² · s · Pa) or less ,tire.   The tire according to claim 1, wherein the resin material contains 50% by mass or more of a polyamide-based thermoplastic elastomer.   3. The tire according to claim 1, wherein a gas permeability of a portion composed of the covering rubber layer and the side rubber layer in the portion of the minimum thickness D 3 is equal to or less than the gas permeability of the tire frame.   The tire according to any one of claims 1 to 3, wherein the thickness D1 is 1.0 mm or more and 2.4 mm or less.