WO2020067473A1 - Tire - Google Patents

Abstract

This tire is provided with a pair of bead portions, at least one of which includes a bead wire, an adhesive layer, a first coating resin layer, and a second coating resin layer, in this order, wherein, in inside and outside directions in the axial direction of the tire, and in an inside direction in the radial direction of the tire, in positions in which the distance from the surface of the bead wire to the outside surface of the second coating resin layer is smallest, a thickness a and a water permeability A of the second coating resin layer, a thickness b and a water permeability B of the first coating resin layer, and a thickness c and a water permeability C of the adhesive layer satisfy the following conditions. (a1) 10 mm ≤ a ≤ 80 mm (b1) 0.05 mm ≤ b ≤ 0.5 mm (c1) 0.005 mm ≤ c ≤ 0.1 mm (A1) A ≤ 300 g·mm/(m²·day) (B1) B ≤ 300 g·mm/(m²·day) (C1) C ≤ 80 g·mm/(m²·day)

Description

tire

The present disclosure relates to a tire.

Conventionally, a pneumatic tire having a pair of bead portions, a pair of tire side portions extending outward from the bead portion in the tire radial direction, and a tread portion extending from one tire side portion to the other tire side portion has been used. ing. In the bead portion of the pneumatic tire, a structure in which a bead core having a bead wire is buried is employed from the viewpoint of improving the fixing performance to the rim.

For example, Patent Literature 1 proposes a tire formed of at least a thermoplastic resin material and having an annular tire skeleton, wherein the thermoplastic resin material includes at least a polyester-based thermoplastic elastomer, Further, a structure in which an annular bead core made of a metal material is embedded is disclosed.

Patent Document 1: Japanese Patent Application Laid-Open No. 2012-046025

As described above, Patent Literature 1 discloses a technology in which an annular bead core made of a metal material is embedded.
However, when water permeates into the bead portion from the outside of the tire, the bead wire may be corroded or deteriorated by the contact with the water. Therefore, from the viewpoint of further improving the durability of the bead portion of the tire, it is conceivable to suppress the penetration of water into the bead wire at the bead portion.

The present disclosure has been made in view of the above circumstances, and aims to provide a tire having excellent durability in a bead portion.

具体 Specific means for solving the above problems include the following embodiments.

<1>
A tire having a pair of bead portions,
At least one of the pair of bead portions has a bead wire, an adhesive layer, a first coating resin layer, and a second coating resin layer in this order,
In a direction where the distance from the surface of the bead wire to the outer surface of the second coating resin layer is minimized in the inward and outward directions in the axial direction of the tire, and in all the inward directions in the radial direction of the tire. The thickness a of the second coating resin layer, the thickness b of the first coating resin layer, and the thickness c of the adhesive layer satisfy the following conditions (a1), (b1) and (c1), respectively: In addition, the water permeability A of the second coating resin layer, the water permeability B of the first coating resin layer, and the water permeability C of the adhesive layer satisfy the following conditions (A1), (B1), and (C1), respectively. Meet the tire.
(A1) 10 mm ≦ a ≦ 80 mm
(B1) 0.05 mm ≦ b ≦ 0.5 mm
(C1) 0.005 mm ≦ c ≦ 0.1 mm
(A1) A ≦ 300 g · mm / (m ² · day)
(B1) B ≦ 300 g · mm / (m ² · day)
(C1) C ≦ 80 g · mm / (m ² · day)

According to the present disclosure, it is possible to provide a tire having excellent durability in a bead portion.

It is a mimetic diagram of a perpendicular section to the length direction of a bead wire which shows an example of a bead part in a tire concerning one embodiment of this indication. In the bead portion shown in FIG. 1A, the distance from the surface of the bead wire to the outer surface of the second coating resin layer is the smallest in the inward and outward directions in the axial direction of the tire, and in the inward direction in the radial direction of the tire. FIG. It is a mimetic diagram of a perpendicular section to the longitudinal direction of a bead wire which shows other examples of a bead part in a tire concerning one embodiment of the present disclosure. In the bead portion shown in FIG. 2A, the distance from the surface of the bead wire to the outer surface of the second coating resin layer is the smallest in the inward and outward directions in the axial direction of the tire and in all the inward directions in the radial direction of the tire. FIG. It is a tire half-sectional view showing one side of a section which cut a tire concerning one embodiment of the present disclosure along a tire width direction.

Hereinafter, specific embodiments of the present disclosure will be described in detail. However, the present disclosure is not limited to the following embodiments, and is implemented with appropriate changes within the scope of the present disclosure. be able to.
The size of the members in each drawing is conceptual, and the relative relationship between the sizes of the members is not limited to this. Members having substantially the same function are denoted by the same reference numerals throughout the drawings, and overlapping description may be omitted.

In this specification, “resin” is a concept including a thermoplastic resin, a thermoplastic elastomer, and a thermosetting resin, and does not include a vulcanized rubber. In the following description of the resin, “the same type” means a resin having a skeleton common to the skeleton constituting the main chain of the resin, such as an ester type or a styrene type.
In this specification, a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit and an upper limit.
In this specification, the term "step" includes not only an independent step but also the term "step" as long as its purpose is achieved, even if it cannot be clearly distinguished from other steps. include.
In the present specification, the amount of each component in the composition is, when a plurality of substances corresponding to each component are present in the composition, unless otherwise specified, the sum of a plurality of substances present in the composition. Means quantity.
In the present specification, the “main component” means a component having the largest content by mass in a mixture unless otherwise specified.

Further, in the present specification, the term "thermoplastic resin" refers to a polymer compound in which a material softens and flows with an increase in temperature and becomes relatively hard and strong when cooled, but does not have rubber-like elasticity.
As used herein, “thermoplastic elastomer” refers to a copolymer having a hard segment and a soft segment. Examples of the thermoplastic elastomer include an elastomer which softens and flows with an increase in temperature, becomes relatively hard and strong when cooled, and has rubber-like elasticity. Specifically, as the thermoplastic elastomer, for example, a polymer that forms a hard segment having a high melting point or a hard segment having a high cohesive force and a polymer that forms an amorphous soft segment having a low glass transition temperature, Copolymer having the same.
The hard segment indicates a component that is relatively harder than the soft segment. The hard segment is preferably a molecular constraint component serving as a crosslinking point of the crosslinked rubber for preventing plastic deformation. For example, as the hard segment, a segment such as a structure having a rigid group such as an aromatic group or an alicyclic group in a main skeleton, or a structure capable of packing between molecules by intermolecular hydrogen bonding or π-π interaction is used. No.
The soft segment indicates a component relatively softer than the hard segment. The soft segment is preferably a flexible component exhibiting rubber elasticity. For example, examples of the soft segment include a segment having a structure in which a main chain has a long-chain group (for example, a long-chain alkylene group or the like), has a high degree of freedom of molecular rotation, and has elasticity.

<Tire>
A tire according to an embodiment of the present disclosure includes a pair of bead portions.
And at least one of the pair of bead portions has a bead wire, an adhesive layer, a first coating resin layer, and a second coating resin layer in this order, and the inner and outer directions in the axial direction of the tire, and The thickness a of the second coating resin layer, where the distance from the surface of the bead wire to the outer surface of the second coating resin layer is minimized in all directions in the radially inward direction of the tire. 1 The thickness b of the coating resin layer and the thickness c of the adhesive layer satisfy the following conditions (a1), (b1) and (c1), respectively, and the water permeability A of the second coating resin layer is The water permeability B of the first coating resin layer and the water permeability C of the adhesive layer satisfy the following conditions (A1), (B1) and (C1), respectively.
(A1) 10 mm ≦ a ≦ 80 mm
(B1) 0.05 mm ≦ b ≦ 0.5 mm
(C1) 0.005 mm ≦ c ≦ 0.1 mm
(A1) A ≦ 300 g · mm / (m ² · day)
(B1) B ≦ 300 g · mm / (m ² · day)
(C1) C ≦ 80 g · mm / (m ² · day)

In the following, a bead member that satisfies the above conditions (A1), (B1) and (C1) is also simply referred to as a “specific bead portion”.

Here, the specific bead portion of the tire will be described with reference to the drawings by way of an example.
FIG. 1A is a cross-sectional view illustrating a cross section orthogonal to the circumferential direction of the bead portion 10. 1A includes a bead core 1 having a bead wire 11, an adhesive layer 12 that covers the bead wire 11, and a first coating resin layer 13 that covers the periphery of the adhesive layer 12. Has a second coating resin layer 14 that covers the periphery of the second resin layer. Further, it has a bead filler 3 extending outward from the second coating resin layer 14 in the tire radial direction. In the bead portion 10 shown in FIG. 1A, the second coating resin layer 14 and the bead filler 3 are drawn as separate bodies, but the second coating resin layer 14 and the bead filler 3 are integrally formed as one body. May be used.
In FIG. 1A, the axial direction of the tire is drawn in the horizontal direction, ie, the directions of arrows Y1 and Y2, and the radial direction of the tire is drawn in the vertical direction, ie, the directions of arrows X1 and X2. Therefore, the outer direction in the tire axial direction is the arrow “Y1” direction, the inner direction in the tire axial direction is the arrow “Y2” direction, the outer direction in the tire radial direction is the arrow “X1” direction, The inward direction in the radial direction of the tire is the direction of the arrow “X2”.

In the present embodiment, the distance from the surface of the bead wire to the outer surface of the second coating resin layer is the smallest in the inward and outward directions in the axial direction of the tire, and in all the inward directions in the radial direction of the tire. At some point, the conditions (a1), (b1), and (c1) are satisfied.
Here, in the present specification, "inward and outward directions in the axial direction of the tire, and all directions inward in the radial direction of the tire", when observing a cross section orthogonal to the circumferential direction of the bead portion, All directions in the direction of 45 ° on both sides from the inner direction in the axial direction, in the direction of 45 ° on both sides from the outer direction in the tire axial direction, and in the direction of 45 ° on both sides from the inner direction in the tire radial direction. Point to. In other words, it means a direction in the entire 270 ° range, excluding the direction in the range of 45 ° on both sides from the outer direction in the tire radial direction.
More specifically, for example, in FIG. 1A, a direction in a range of 45 ° on both sides from the inward direction (arrow Y2 direction) in the tire axial direction (that is, a range indicated by θ3) and an outward direction in the tire axial direction (arrow Y1 direction) ), And a direction in a range of 45 ° on both sides from the inside direction (direction of arrow X2) in the tire radial direction (ie, a range indicated by θ4) in a range of 45 ° on both sides (ie, a range indicated by θ2). In all directions. In other words, it means the direction of the entire range excluding the direction in the range of 45 ° on both sides from the outer direction (direction of arrow X1) in the tire radial direction (that is, the range indicated by θ1).

In the present embodiment, the bead wires are formed in the inward and outward directions in the axial direction of the tire, and in all the inward directions in the radial direction of the tire (hereinafter, also simply referred to as “specific target directions” in the present specification). The location where the distance from the surface to the outer surface of the second coating resin layer is minimum is targeted. That is, in the case of the bead portion 10 shown in FIG. 1A, the distance from the surface of the bead wire 11 to the outer surface of the second coating resin layer 14 in a specific target direction (that is, a direction in a range indicated by θ2, θ3, and θ4). The minimum location [m1] is the target. FIG. 1B is an enlarged view of a portion [m1] in FIG. 1A.
In the bead portion 10 shown in FIG. 1B, the thickness a of the second coating resin layer 14, the thickness b of the first coating resin layer 13, and the thickness c of the adhesive layer 12 at the point [m1] are (a1 ), (B1) and (c1).
In the bead portion 10, the water permeability A of the second covering resin layer 14, the water permeability B of the first covering resin layer 13, and the water permeability C of the adhesive layer 12 are (A1) and (B1), respectively. And (C1).

Further, the specific bead portion of the tire is not limited to the embodiment shown in FIG. 1A, and may be, for example, an embodiment having a plurality of bead wires. Here, an embodiment having a plurality of bead wires will be described with reference to the drawings by further giving an example.
FIG. 2A is a cross-sectional view illustrating a cross section orthogonal to the circumferential direction of the bead portion 110. FIG. 2A shows a bead portion 110 in which three bead wires 111 are arranged in parallel and stacked in three stages, that is, in an embodiment having nine bead wires 111. Each bead wire 111 is covered with an adhesive layer 112, and the periphery of the bead wire 111 and the adhesive layer 112 is covered with a first covering resin layer 113 to form a bead core 101. Further, a second coating resin layer 114 covering the periphery of the bead core 101 is provided. In addition, it has a bead filler 103 extending outward from the second coating resin layer 114 in the tire radial direction. In the bead portion 110 shown in FIG. 2A, the second coating resin layer 114 and the bead filler 103 are drawn as separate bodies, but the second coating resin layer 114 and the bead filler 103 are integrally formed in the same body. May be used.
In FIG. 2A, the outer direction in the axial direction of the tire is an arrow “Y1” direction, the inner direction in the axial direction of the tire is an arrow “Y2” direction, and the outer direction in the radial direction of the tire is an arrow “X1” direction. The inner direction in the tire radial direction is the direction of the arrow “X2”.

In the bead portion 110 shown in FIG. 2A, a direction in a range of 45 ° on both sides from a specific target direction (that is, an inner direction (arrow Y2 direction) in the tire axial direction) and an outer direction (arrow Y1 direction) in the tire axial direction. The second coating resin extends from the surface of the bead wire 111 in a direction of a range of 45 ° on both sides and a direction of an inner side in the tire radial direction (direction of arrow X2) in a range of 45 ° on both sides in all 270 ° directions. At the point where the distance to the outer surface of the layer 114 is minimum, the conditions (a1), (b1), and (c1) are satisfied. In the case of having a plurality of bead wires, as shown in FIG. 2A, a portion of the plurality of bead wires 111 from the surface of the bead wire 111 in a specific target direction to the outer surface of the second coating resin layer 114. One line having the minimum distance is selected, and a portion [m2] where the distance is minimum is targeted. FIG. 2B is an enlarged view of a portion [m2] in FIG. 2A.
2B, at the point [m2], the thickness a of the second coating resin layer 114, the thickness b of the first coating resin layer 113, and the thickness c of the adhesive layer 112 are respectively the same. The conditions (a1), (b1), and (c1) are satisfied.
In the bead portion 110, the water permeability A of the second covering resin layer 114, the water permeability B of the first covering resin layer 113, and the water permeability C of the adhesive layer 112 are (A1) and (B1), respectively. , And (C1).

According to the tire satisfying such a configuration, a tire having excellent bead portion durability can be provided.

Conventionally, a bead having a bead wire, an adhesive layer, a first coating resin layer, and a second coating resin layer in this order has been used as a bead that plays a role of fixing the tire to a rim. Note that a metal wire such as a steel cord, a resin wire, and the like are often used as bead wires. When water permeates from the outside of the tire to the inside of the bead portion and reaches the bead wire, the bead wire may be corroded or deteriorated by contact with water. Further, when a rubber member is present around the bead portion, water in which the additive in the rubber is dissolved permeates into the bead portion, and the bead wire may be deteriorated by contact with the additive. .
Therefore, it is required to suppress the penetration of water into the bead wire in the bead portion.

On the other hand, the tire satisfies the conditions (a1), (b1), (c1), (A1), (B1), and (C1) in the bead portion.
The adhesive layer closest to the bead wire among the adhesive layer, the first coating resin layer, and the second coating resin layer is required to be thin from the viewpoint of maintaining adhesiveness, strength, and suppressing cracking due to impact. Specifically, it is required that the condition (c1) 0.005 mm ≦ c ≦ 0.1 mm is satisfied. On the other hand, since the adhesive layer closest to the bead wire is required to have a high property of suppressing water penetration, on the assumption that the above condition (c1) is satisfied, the water permeability is (C1) C ≦ 80 g · mm / (M ² · day) is required to be satisfied. Further, the second coating resin layer and the first coating resin layer disposed on the adhesive layer each have a water permeability (A1) A ≦ 300 g · mm / ^(m 2 · day) and to meet the (B1) B ≦ 300g · mm / (m 2 · day) is determined. Furthermore, the thickness of the first coating resin layer satisfies (b1) 0.05 mm ≦ b ≦ 0.5 mm from both viewpoints of moldability, adhesiveness, strength, and the like and suppression of water penetration. On the other hand, the thickness of the second coating resin layer is required to be thicker than the adhesive layer and the first coating resin layer from the viewpoint of suppressing water penetration, that is, (a1) satisfying 10 mm ≦ a ≦ 80 mm Is required.
Therefore, regarding the thickness and water permeability of each layer in the bead portion, the adhesive layer satisfies the conditions (c1) and (C1), the first coating resin layer satisfies the conditions (b1) and (B1), and further, the second coating resin layer satisfies the conditions (b1) and (B1). When the resin layer satisfies the conditions (a1) and (A1), permeation of water into the bead wire is suppressed, and a tire having excellent bead portion durability is provided.

The thickness of the adhesive layer and the water permeability In a specific target direction, a location where the distance from the surface of the bead wire to the outer surface of the second coating resin layer is minimum (for example, the location [m1] in FIGS. 1A and 1B, In FIG. 2A and FIG. 2B, at the position [m2]), the thickness c of the adhesive layer satisfies (c1) below. In addition, it is preferable to satisfy the following (c2), and it is more preferable to satisfy the following (c3).
(C1) 0.005 mm ≦ c ≦ 0.1 mm
(C2) 0.005 mm ≦ c ≦ 0.05 mm
(C3) 0.005 mm ≦ c ≦ 0.01 mm
When the thickness c of the adhesive layer is 0.005 mm or more, penetration of water into the bead wire is suppressed, and the durability of the bead portion is excellent. On the other hand, the thickness c of the adhesive layer is set to 0.1 mm or less from the viewpoint of maintaining adhesiveness, strength, and suppressing cracking due to impact.

The water permeability C of the adhesive layer satisfies the following (C1). In addition, it is preferable that the following (C2) is satisfied, and it is more preferable that the following (C3) is satisfied.
(C1) C ≦ 80 g · mm / (m ² · day)
(C2) 5 g · mm / (m ² · day) ≦ C ≦ 50 g · mm / (m ² · day)
(C3) 10 g · mm / (m ² · day) ≦ C ≦ 30 g · mm / (m ² · day)
When the water permeability C of the adhesive layer is 80 g · mm / (m ² · day) or less, permeation of water into the bead wire is suppressed, and the durability of the bead portion is excellent. On the other hand, the water permeability C of the adhesive layer is preferably 3 g · mm / (m ² · day) or more from the viewpoint of the degree of freedom in selecting the adhesive.

-Thickness and water permeability of the first coating resin layer In a specific target direction, the thickness of the first coating resin layer at a point where the distance from the surface of the bead wire to the outer surface of the second coating resin layer is minimum. b satisfies the following (b1). In addition, it is preferable to satisfy the following (b2), and it is more preferable to satisfy the following (b3).
(B1) 0.05 mm ≦ b ≦ 0.5 mm
(B2) 0.05 mm ≦ b ≦ 0.1 mm
(B3) 0.05 mm ≦ b ≦ 0.08 mm
When the thickness b of the first coating resin layer is 0.05 mm or more, permeation of water into the bead wire is suppressed, and the durability of the bead portion is excellent. On the other hand, the thickness b of the first coating resin layer is set to 0.5 mm or less from both viewpoints of moldability, adhesiveness, strength, and the like and suppression of water penetration.

The water permeability B of the first coating resin layer satisfies the following (B1). In addition, it is preferable to satisfy the following (B2), and it is more preferable to satisfy the following (B3).
(B1) B ≦ 300 g · mm / (m ² · day)
(B2) 25 g · mm / (m ² · day) ≦ B ≦ 280 g · mm / (m ² · day)
(B3) 50 g · mm / (m ² · day) ≦ B ≦ 220 g · mm / (m ² · day)
When the water permeability B of the first coating resin layer is 300 g · mm / (m ² · day) or less, permeation of water into the bead wire is suppressed, and the durability of the bead portion is excellent. On the other hand, the water permeability B of the first coating resin layer is preferably 25 g · mm / (m ² · day) or more from the viewpoint of the degree of freedom in selecting the resin.

-Thickness and water permeability of the second coating resin layer In a specific target direction, the thickness of the second coating resin layer at a point where the distance from the surface of the bead wire to the outer surface of the second coating resin layer is minimum. a satisfies the following (a1). In addition, it is preferable to satisfy the following (a2), and it is more preferable to satisfy the following (a3).
(A1) 10 mm ≦ a ≦ 80 mm
(A2) 10 mm ≦ a ≦ 50 mm
(A3) 10 mm ≦ a ≦ 25 mm
When the thickness a of the second coating resin layer is 10 mm or more, penetration of water into the bead wire is suppressed, and the durability of the bead portion is excellent. On the other hand, the thickness a of the second coating resin layer is set to 80 mm or less from the viewpoint of material cost and bulk durability.

The water permeability A of the second coating resin layer satisfies the following (A1). In addition, it is preferable to satisfy the following (A2), and it is more preferable to satisfy the following (A3).
(A1) A ≦ 300 g · mm / (m ² · day)
(A2) 25 g · mm / (m ² · day) ≦ A ≦ 280 g · mm / (m ² · day)
(A3) 50 g · mm / (m ² · day) ≦ A ≦ 220 g · mm / (m ² · day)
When the water permeability A of the second coating resin layer is 300 g · mm / (m ² · day) or less, permeation of water into the bead wire is suppressed, and the durability of the bead portion is excellent. On the other hand, the water permeability A of the second coating resin layer is preferably 25 g · mm / (m ² · day) or more from the viewpoint of the degree of freedom in selecting the resin.

-Ratio of water permeability The ratio of the water permeability A of the second coating resin layer to the water permeability C of the adhesive layer preferably satisfies the following condition (RA1), and more preferably satisfies the following (RA2). More preferably, it satisfies the following (RA3).
(RA1) 2.50 ≦ A / C
(RA2) 2.75 ≦ A / C ≦ 40
(RA3) 2.75 ≦ A / C ≦ 20
When the ratio [A / C] of the water permeability C of the adhesive layer to the water permeability A of the second coating resin layer is 2.50 or more, permeation of water into the bead wire is suppressed, and the durability of the bead portion is improved. Excellent in nature. On the other hand, the ratio [A / C] is preferably 40 or less from the viewpoint of the degree of freedom in selecting the resin of the second coating resin layer.

The ratio of the water permeability B of the first coating resin layer to the water permeability C of the adhesive layer preferably satisfies the following condition (RB1), more preferably satisfies the following (RB2), and more preferably satisfies the following (RB3) It is more preferable to satisfy the following.
(RB1) 1.47 ≦ B / C
(RB2) 2.00 ≦ B / C ≦ 100
(RB3) 2.75 ≦ B / C ≦ 50
When the ratio [B / C] of the water permeability C of the adhesive layer and the water permeability B of the first coating resin layer is 1.47 or more, permeation of water into the bead wire is suppressed, and the durability of the bead portion is improved. Excellent in nature. On the other hand, the ratio [B / C] is preferably 100 or less from the viewpoint of the degree of freedom in selecting the resin of the first coating resin layer.

The ratio of the water permeability B of the first coating resin layer to the water permeability A of the second coating resin layer preferably satisfies the following condition (RC1), more preferably satisfies the following (RC2), and More preferably, (RC3) is satisfied.
(RC1) 0.50 ≦ B / A
(RC2) 0.70≤B / A≤3.00
(RC3) 1.00 ≦ B / A ≦ 2.00
When the ratio [B / A] of the water permeability A of the second coating resin layer to the water permeability B of the first coating resin layer is 0.50 or more, the penetration of water into the bead wire is suppressed and the bead is formed. The durability of the part is excellent. On the other hand, the ratio [B / A] is preferably 3.00 or less from the viewpoint of the degree of freedom in selecting the resin of the first coating resin layer.

-Melt viscosity The melt viscosity of the second coating resin layer at 270 ° C is preferably 150 Pa · s or more and 600 Pa · s or less, more preferably 150 Pa · s or more and 300 Pa · s or less, and 150 Pa · s or more. More preferably, it is 250 Pa · s or less.
When the melt viscosity of the second coating resin layer is 150 Pa · s or more, excellent adhesion to the second coating resin layer is ensured. On the other hand, when the melt viscosity is 600 Pa · s or less, the moldability of the second coating resin layer (particularly, the moldability when forming the second coating resin layer by injection molding) is excellent.

The ratio of the melt viscosity Mb at 270 ° C. of the first coating resin layer to the melt viscosity Ma at 270 ° C. of the second coating resin layer preferably satisfies the following condition (Ma1), and satisfies the following condition (Ma2). Is more preferable, and it is still more preferable to satisfy the following (Ma3).
(Ma1) 0.4 ≦ Mb / Ma ≦ 2.5
(Ma2) 0.5 ≦ Mb / Ma ≦ 2.0
(Ma3) 0.8 ≦ Mb / Ma ≦ 1.5
The fact that the ratio [Mb / Ma] of the melt viscosity between the second coating resin layer and the first coating resin layer is 0.4 or more means that the melt viscosity Ma of the second coating resin layer and the melt viscosity of the first coating resin layer. This indicates that Mb is not too far away, whereby excellent adhesion between the second coating resin layer and the first coating resin layer is exhibited. On the other hand, the ratio [Mb / Ma] is preferably 2.5 or less from the same viewpoint as described above.

In addition, from the viewpoint of satisfying the above ratio [Mb / Ma], the melt viscosity at 270 ° C. of the first coating resin layer is preferably 150 Pa · s or more and 600 Pa · s or less, and 150 Pa · s or more and 300 Pa · s or less. Is more preferable, and more preferably 150 Pa · s or more and 250 Pa · s or less.

The melt viscosity Mc at 270 ° C. of the adhesive layer is preferably 10 Pa · s or more and 3000 Pa · s or less, more preferably 30 Pa · s or more and 2500 Pa · s or less, and 50 Pa · s or more and 2000 Pa · s or less. It is more preferred that there be.

-Measurement method In the measurement of the thickness of each layer, first, an enlarged image of a vertical section perpendicular to the length direction of the bead wire by a microscope such as a video microscope is acquired from any five places. Then, for a portion where the distance from the surface of the bead wire to the outer surface of the second coating resin layer in the specific target direction is minimum, the number average value of the thickness of each layer measured from each obtained enlarged image is used.

The water permeability of each layer is measured by measuring the moisture permeability of the sample in accordance with JIS Z 0208: 1976 (80 ° C., 90% RH, 80 ° C., moisture permeability test method for moisture-proof packaging material). .

The melt viscosity of each layer is measured for the sample using a flow tester (CFT-D, manufactured by Shimadzu Corporation) under the following measurement conditions: temperature 270 ° C., load 1.00 kg, interval 25 mm, orifice 1.00 Φ × 10 L (mm). .
In addition, the sample used for the measurement of the water permeability and the melt viscosity may be a sample piece of each layer obtained directly from the bead portion. Further, when it is not easy to obtain a sample piece serving as a sample, a sample piece serving as a sample may be separately manufactured using the same material as that used for forming each layer.

Next, in the above-mentioned tire, materials and the like constituting each member (bead wire, adhesive layer, first coating resin layer, second coating resin layer, etc.) in the bead portion will be described.

The bead portion includes a bead core having a bead wire, an adhesive layer provided on the bead wire, and a first coating resin layer provided around the adhesive layer. In addition, a second coating resin layer provided around the bead core is provided. Note that a bead filler extending from the second coating resin layer 14 outward in the tire radial direction may be further provided.

[Bead wire]
The bead wire is not particularly limited, and for example, a metal cord or an organic resin cord used for a conventional rubber tire can be used as appropriate. For example, it is composed of a monofilament (single wire) such as a metal fiber or an organic fiber, or a multifilament (twisted wire) obtained by twisting these fibers. Among them, a metal cord is preferable, and an iron cord, that is, a steel cord is more preferable.

As the bead wire, a monofilament (single wire) is preferable from the viewpoint of further improving the durability of the tire. The cross-sectional shape, size (diameter) and the like of the bead wire are not particularly limited, and a wire suitable for a desired tire can be appropriately selected and used.
When the bead wire is a stranded wire of a plurality of cords, the number of the plurality of cords is, for example, 2 to 10, preferably 5 to 9.

The surface of the bead wire is made of a metal material containing, as a main component, at least one metal element selected from the group consisting of Cu, Zn, Fe, Al, and Co from the viewpoint of adhesiveness with the adhesive layer. Is preferred.
For example, a steel cord is an example of a configuration mainly containing an Fe element.
In addition, as a configuration mainly containing at least one metal element selected from the group consisting of Cu, Zn, Al, and Co, a configuration in which the surface of a steel cord is covered by plating is given.

方法 The method of forming the plating on the surface of the cord is not particularly limited, and can be performed by a known method. For example, a plating process is performed by immersing a cord serving as a core wire of a plated element wire into, for example, a copper plating bath, a zinc plating bath, or the like. For example, when forming copper plating, it is treated by a copper cyanide bath, a copper borofluoride bath, a copper sulfate bath, etc., and in the case of zinc plating, it is treated by a zinc cyanide bath, a zinc chloride bath, a zincate bath, or the like. You. A heat diffusion treatment may be applied to the cord immersed in the plating bath. After that, the cord may be drawn from the viewpoint of a predetermined plating thickness.

(4) The amount of plating applied is, for example, preferably 0.1 μm or more and 10 μm or less, more preferably 0.2 μm or more and 8.0 μm or less, as an average thickness of the plating. The plating thickness can be measured by observation with a scanning electron microscope (SEM).

The thickness (that is, the average diameter) of the bead wire is preferably from 0.3 mm to 3 mm, and more preferably from 0.5 mm to 2 mm, from the viewpoint of achieving both the internal pressure resistance and the weight reduction of the tire. The thickness of the bead wire is a number average value of the thickness measured at five arbitrarily selected cross sections (a cross section perpendicular to the length direction of the bead wire).

(4) The strength of the bead wire itself is usually from 1000 N to 3000 N, preferably from 1200 N to 2800 N, and more preferably from 1300 N to 2700 N. The strength of the bead wire is calculated from a breaking point by drawing a stress-strain curve using a ZWICK type chuck with a tensile tester.

The elongation at break (tensile elongation at break) of the bead wire itself is usually 0.1% to 15%, preferably 1% to 15%, more preferably 1% to 10%. The tensile elongation at break of the bead wire can be determined from the strain by drawing a stress-strain curve using a ZWICK type chuck with a tensile tester.

[Adhesive layer]
As the material of the adhesive layer, a material that satisfies the requirement (condition (C1)) of the water permeability C described above is used.

The adhesive layer is preferably a layer containing a resin as an adhesive, and is preferably a thermoplastic resin or a thermoplastic elastomer.
In addition, as a method of controlling the water transmittance C of the adhesive layer to a range that satisfies the condition (C1), a method of selecting the type of the resin in the adhesive layer, adjusting the content of the resin, and the like can be mentioned.

Examples of the thermoplastic resin include a polyester-based thermoplastic resin, a polyamide-based thermoplastic resin, a polystyrene-based thermoplastic resin, a polyurethane-based thermoplastic resin, and an olefin-based thermoplastic resin (eg, a polyethylene resin and a polypropylene resin). Can be
Examples of the thermoplastic elastomer include a polyester-based thermoplastic elastomer, a polyamide-based thermoplastic elastomer, a polystyrene-based thermoplastic elastomer, a polyurethane-based thermoplastic elastomer, and an olefin-based thermoplastic elastomer.

Among them, the resin used as the adhesive includes a polyester thermoplastic elastomer, a polyester thermoplastic resin, an olefin thermoplastic elastomer, an olefin thermoplastic resin, a polyamide thermoplastic elastomer, and a polyamide thermoplastic resin. It preferably contains at least one selected from the group consisting of polyester, and more preferably contains a polyester thermoplastic elastomer.

酸 It is also preferable to use an acid-modified thermoplastic material for the resin used as the adhesive. The acid-modified thermoplastic material is a thermoplastic material in which an acid group is introduced into a part of a molecule of a thermoplastic resin or a thermoplastic elastomer. Examples of the acid group include a carboxy group (—COOH) and its anhydride group, a sulfate group, a phosphate group and the like, and among them, the carboxy group and its anhydride group are preferable.

The adhesive layer may be used alone or in combination of two or more thermoplastic resins and thermoplastic elastomers.

(4) The content of the resin contained in the adhesive layer is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 75% by mass or more of the whole adhesive layer.

[First coating resin layer]
As the material of the first coating resin layer, a material that satisfies the above requirement of water permeability B (condition (B1)) is used.

The first coating resin layer contains a resin. The method of controlling the water permeability B of the first coating resin layer to be in a range satisfying the condition (B1) includes selection of the type of the resin in the first coating resin layer and adjustment of the content of the resin. Method.
Examples of the resin contained in the first coating resin layer include a thermoplastic resin, a thermoplastic elastomer, and a thermosetting resin.
The first coating resin layer preferably contains, as a resin, a thermoplastic resin or a thermoplastic elastomer from the viewpoint of moldability, and more preferably contains a thermoplastic elastomer.

The first coating resin layer only needs to contain at least the resin, and may contain other components such as additives as long as the effects of the present embodiment are not impaired. However, the content of the resin in the first coating resin layer is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 75% by mass or more based on the total amount of the first coating resin layer.

Examples of the thermoplastic resin include a polyester-based thermoplastic resin, a polyamide-based thermoplastic resin, an olefin-based thermoplastic resin, a polyurethane-based thermoplastic resin, a vinyl chloride-based thermoplastic resin, and a polystyrene-based thermoplastic resin.
Examples of the thermoplastic elastomer include polyester-based thermoplastic elastomer (TPC), polyamide-based thermoplastic elastomer (TPA), polystyrene-based thermoplastic elastomer (TPS), polyurethane-based thermoplastic elastomer (TPU) specified in JIS K6418, An olefin-based thermoplastic elastomer (TPO), a crosslinked thermoplastic rubber (TPV), or another thermoplastic elastomer (TPZ) may be used.
Examples of the thermosetting resin include a phenol-based thermosetting resin, a urea-based thermosetting resin, a melamine-based thermosetting resin, and an epoxy-based thermosetting resin.

Among them, the resin used for the first coating resin layer includes polyester-based thermoplastic elastomer, polyester-based thermoplastic resin, olefin-based thermoplastic elastomer, olefin-based thermoplastic resin, polyamide-based thermoplastic elastomer, and polyamide-based thermoplastic resin. It is preferable to include at least one selected from the group consisting of: and more preferably a polyester-based thermoplastic elastomer.

It is also preferable to use an acid-modified thermoplastic material for the resin used for the first coating resin layer. Examples of the acid group in the acid modification include a carboxy group (—COOH) and its anhydride group, a sulfate group, a phosphoric acid group, and the like. Among them, a carboxy group and its anhydride group are preferable.

Here, various thermoplastic elastomers and thermoplastic resins will be described in detail.

-Thermoplastic elastomer-
(Polyester thermoplastic elastomer)
As the polyester-based thermoplastic elastomer, for example, at least polyester forms a hard segment having a crystalline and high melting point and another polymer (eg, polyester or polyether) has an amorphous and soft segment having a low glass transition temperature. The material being formed is mentioned.

As the polyester forming the hard segment, an aromatic polyester can be used. The aromatic polyester can be formed, for example, from an aromatic dicarboxylic acid or an ester-forming derivative thereof and an aliphatic diol. The aromatic polyester is preferably polybutylene terephthalate derived from at least one selected from the group consisting of terephthalic acid and dimethyl terephthalate, and 1,4-butanediol. Further, aromatic polyesters include, for example, isophthalic acid, phthalic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-2,7-dicarboxylic acid, diphenyl-4,4′-dicarboxylic acid, diphenoxyethanedicarboxylic acid, A dicarboxylic acid component such as sulfoisophthalic acid or an ester-forming derivative thereof, and a diol having a molecular weight of 300 or less (eg, ethylene glycol, trimethylene glycol, pentamethylene glycol, hexamethylene glycol, neopentyl glycol, decamethylene glycol, etc.) Aliphatic diols; alicyclic diols such as 1,4-cyclohexanedimethanol and tricyclodecanedimethylol; xylylene glycol, bis (p-hydroxy) diphenyl, bis (p-hydroxyphenyl) propane, 2,2- Bi [4- (2-hydroxyethoxy) phenyl] propane, bis [4- (2-hydroxy) phenyl] sulfone, 1,1-bis [4- (2-hydroxyethoxy) phenyl] cyclohexane, 4,4′- Aromatic diols such as dihydroxy-p-terphenyl and 4,4'-dihydroxy-p-quarterphenyl; etc.), and polyesters derived therefrom, or a mixture of two or more of these dicarboxylic acid components and diol components. It may be a polymerized polyester. It is also possible to copolymerize a trifunctional or higher polyfunctional carboxylic acid component, a polyfunctional oxyacid component, a polyfunctional hydroxy component or the like in a range of 5 mol% or less.
Examples of the polyester forming the hard segment include polyethylene terephthalate, polybutylene terephthalate, polymethylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, and the like, with polybutylene terephthalate being preferred.

Examples of the polymer that forms the soft segment include aliphatic polyester and aliphatic polyether.
Examples of the aliphatic polyether include poly (ethylene oxide) glycol, poly (propylene oxide) glycol, poly (tetramethylene oxide) glycol, poly (hexamethylene oxide) glycol, a copolymer of ethylene oxide and propylene oxide, and poly (propylene oxide). ) Ethylene oxide addition polymers of glycols and copolymers of ethylene oxide and tetrahydrofuran.
Examples of the aliphatic polyester include poly (ε-caprolactone), polyenantholactone, polycaprylolactone, polybutylene adipate, polyethylene adipate and the like.
Among these aliphatic polyethers and aliphatic polyesters, from the viewpoint of the elastic properties of the obtained polyester block copolymer, polymers forming soft segments include poly (tetramethylene oxide) glycol and poly (propylene oxide) glycol. Preferred are ethylene oxide adducts, poly (ε-caprolactone), polybutylene adipate, polyethylene adipate and the like.

数 Further, the number average molecular weight of the polymer forming the soft segment is preferably from 300 to 6000 from the viewpoint of toughness and low-temperature flexibility. Further, the mass ratio (x: y) of the hard segment (x) to the soft segment (y) is preferably from 99: 1 to 20:80, more preferably from 98: 2 to 30:70 from the viewpoint of moldability. .

組合 せ As a combination of the above-mentioned hard segment and soft segment, for example, each combination of the above-mentioned hard segment and soft segment can be given. Among these, as the combination of the above-mentioned hard segment and soft segment, a combination in which the hard segment is polybutylene terephthalate and the soft segment is an aliphatic polyether is preferable, and the hard segment is polybutylene terephthalate, and the soft segment is Are more preferably poly (ethylene oxide) glycols.

Commercially available polyester-based thermoplastic elastomers include, for example, "Hytrel" series (for example, 3046, 5557, 6347, 4047N, 4767N, etc.) manufactured by Dupont Toray, and "Perprene" series, manufactured by Toyobo Co., Ltd. (For example, P30B, P40B, P40H, P55B, P70B, P150B, P280B, E450B, P150M, S1001, S2001, S5001, S6001, S9001, etc.) can be used.

The polyester-based thermoplastic elastomer can be synthesized by copolymerizing a polymer forming a hard segment and a polymer forming a soft segment by a known method.

(Polyamide thermoplastic elastomer)
Polyamide-based thermoplastic elastomer is a thermoplastic resin material composed of a copolymer having a polymer which forms a hard segment having a high melting point which is crystalline and a polymer which forms an amorphous soft segment having a low glass transition temperature. In addition, a polymer having an amide bond (—CONH—) in the main chain of a polymer forming a hard segment is meant.
As the polyamide-based thermoplastic elastomer, for example, at least a polyamide forms a hard segment having a crystalline and high melting point, and another polymer (for example, polyester, polyether, etc.) has an amorphous and a soft segment having a low glass transition temperature. The material being formed is mentioned. Further, the polyamide-based thermoplastic elastomer may be formed by using a chain extender such as dicarboxylic acid in addition to the hard segment and the soft segment.
Specific examples of the polyamide-based thermoplastic elastomer include an amide-based thermoplastic elastomer (TPA) specified in JIS K6418: 2007, and a polyamide-based elastomer described in JP-A-2004-346273. it can.

に お い て In the polyamide-based thermoplastic elastomer, examples of the polyamide forming the hard segment include a polyamide formed by a monomer represented by the following general formula (1) or (2).

In the general formula (1), R ¹ represents a molecular chain of a hydrocarbon having 2 to 20 carbon atoms (for example, an alkylene group having 2 to 20 carbon atoms).

In the general formula (2), R ² represents a molecular chain of a hydrocarbon having 3 to 20 carbon atoms (for example, an alkylene group having 3 to 20 carbon atoms).

In the general formula (1), R ¹ is preferably a hydrocarbon molecular chain having 3 to 18 carbon atoms, for example, an alkylene group having 3 to 18 carbon atoms, and a molecular chain of a hydrocarbon having 4 to 15 carbon atoms, for example, carbon atom. An alkylene group having 4 to 15 carbon atoms is more preferable, and a hydrocarbon chain having 10 to 15 carbon atoms, for example, an alkylene group having 10 to 15 carbon atoms is particularly preferable.
Further, in the general formula (2), as R ² , a molecular chain of a hydrocarbon having 3 to 18 carbon atoms, for example, an alkylene group having 3 to 18 carbon atoms is preferable, and a molecular chain of a hydrocarbon having 4 to 15 carbon atoms; For example, an alkylene group having 4 to 15 carbon atoms is more preferable, and a molecular chain of a hydrocarbon having 10 to 15 carbon atoms, for example, an alkylene group having 10 to 15 carbon atoms is particularly preferable.
Examples of the monomer represented by the general formula (1) or (2) include ω-aminocarboxylic acid or lactam. Examples of the polyamide forming the hard segment include polycondensates of these ω-aminocarboxylic acids or lactams, and copolycondensates of diamines and dicarboxylic acids.

Examples of the ω-aminocarboxylic acid include those having 5 to 20 carbon atoms such as 6-aminocaproic acid, 7-aminoheptanoic acid, 8-aminooctanoic acid, 10-aminocapric acid, 11-aminoundecanoic acid and 12-aminododecanoic acid. Examples thereof include aliphatic ω-aminocarboxylic acids. Examples of the lactam include aliphatic lactams having 5 to 20 carbon atoms, such as lauryl lactam, ε-caprolactam, udecan lactam, ω-enantholactam, and 2-pyrrolidone.
Examples of the diamine include an aliphatic diamine having 2 to 20 carbon atoms and an aromatic diamine having 6 to 20 carbon atoms. Examples of the aliphatic diamine having 2 to 20 carbon atoms and the aromatic diamine having 6 to 20 carbon atoms include ethylene diamine, trimethylene diamine, tetramethylene diamine, hexamethylene diamine, heptamethylene diamine, octamethylene diamine, nonamethylene diamine, and the like. Decamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2,2,4-trimethylhexamethylenediamine, 2,4,4-trimethylhexamethylenediamine, 3-methylpentamethylenediamine, metaxylenediamine and the like. it can.
The dicarboxylic acid can be represented by HOOC- (R ³ ) _m —COOH (R ³ : a molecular chain of a hydrocarbon having 3 to 20 carbon atoms, m: 0 or 1). For example, oxalic acid, succinic acid And aliphatic dicarboxylic acids having 2 to 20 carbon atoms such as glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid and dodecane diacid.
As the polyamide forming the hard segment, a polyamide obtained by ring-opening polycondensation of lauryl lactam, ε-caprolactam, or udecan lactam can be preferably used.

Examples of the polymer forming the soft segment include polyester and polyether, and specific examples include polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, and ABA-type triblock polyether. These can be used alone or in combination of two or more. Further, a polyether diamine or the like obtained by reacting ammonia or the like with the terminal of the polyether can also be used.
Here, the “ABA-type triblock polyether” means a polyether represented by the following general formula (3).

中 In the general formula (3), x and z represent an integer of 1 to 20. y represents an integer of 4 to 50.

In the general formula (3), x and z are each preferably an integer of 1 to 18, more preferably an integer of 1 to 16, further preferably an integer of 1 to 14, and particularly preferably an integer of 1 to 12. In the general formula (3), y is preferably an integer of 5 to 45, more preferably an integer of 6 to 40, further preferably an integer of 7 to 35, and particularly preferably an integer of 8 to 30.

組合 せ As the combination of the hard segment and the soft segment, the respective combinations of the hard segment and the soft segment described above can be cited. Among these, the combination of a hard segment and a soft segment includes a combination of lauryl lactam ring-opening polycondensate / polyethylene glycol, a combination of lauryl lactam ring-opening polycondensate / polypropylene glycol, and a ring-opening polycondensation of lauryl lactam The combination of isomer / polytetramethylene ether glycol, or the combination of ring-opening polycondensate of lauryl lactam / ABA type triblock polyether is preferable, and the combination of ring-opening polycondensate of lauryl lactam / ABA type triblock polyether is more preferable preferable.

数 The number average molecular weight of the polymer (polyamide) forming the hard segment is preferably from 300 to 15,000 from the viewpoint of melt moldability. The number average molecular weight of the polymer forming the soft segment is preferably from 200 to 6000 from the viewpoint of toughness and flexibility at low temperature. Further, the mass ratio (x: y) to the hard segment (x) and the soft segment (y) is preferably from 50:50 to 90:10, and more preferably from 50:50 to 80:20 from the viewpoint of moldability. .

The polyamide-based thermoplastic elastomer can be synthesized by copolymerizing a polymer forming a hard segment and a polymer forming a soft segment by a known method.

Commercially available polyamide-based thermoplastic elastomers include, for example, Ube Industries, Ltd.'s "UBESTA @ XPA" series (eg, XPA9068X1, XPA9063X1, XPA9055X1, XPA9048X2, XPA9048X1, XPA9040X1, XPA9040X2XPA9044), and Daicel Eponik. "Vestamide" series (eg, E40-S3, E47-S1, E47-S3, E55-S1, E55-S3, EX9200, E50-R2, etc.) can be used.

(Polystyrene-based thermoplastic elastomer)
As the polystyrene-based thermoplastic elastomer, for example, at least polystyrene forms a hard segment, and another polymer (eg, polybutadiene, polyisoprene, polyethylene, hydrogenated polybutadiene, hydrogenated polyisoprene, etc.) is amorphous and has a glass transition temperature. Low soft segment. As the polystyrene forming the hard segment, for example, those obtained by a known radical polymerization method, ionic polymerization method, or the like are preferably used, and specific examples include polystyrene having anion living polymerization. Examples of the polymer forming the soft segment include polybutadiene, polyisoprene, and poly (2,3-dimethyl-butadiene).

組合 せ As the combination of the hard segment and the soft segment, the respective combinations of the hard segment and the soft segment described above can be cited. Among them, the combination of the hard segment and the soft segment is preferably a combination of polystyrene / polybutadiene or a combination of polystyrene / polyisoprene. Further, in order to suppress an unintended crosslinking reaction of the thermoplastic elastomer, the soft segment is preferably hydrogenated.

The number average molecular weight of the polymer (polystyrene) forming the hard segment is preferably from 5,000 to 500,000, more preferably from 10,000 to 200,000.
The number average molecular weight of the polymer forming the soft segment is preferably from 5,000 to 1,000,000, more preferably from 10,000 to 800,000, even more preferably from 30,000 to 500,000. Further, the volume ratio (x: y) of the hard segment (x) and the soft segment (y) is preferably from 5:95 to 80:20, more preferably from 10:90 to 70:30 from the viewpoint of moldability. .

The polystyrene-based thermoplastic elastomer can be synthesized by copolymerizing a polymer forming a hard segment and a polymer forming a soft segment by a known method.
Examples of the polystyrene-based thermoplastic elastomer include styrene-butadiene-based copolymer [SBS (polystyrene-poly (butylene) block-polystyrene), SEBS (polystyrene-poly (ethylene / butylene) block-polystyrene)], styrene-isoprene Copolymer (polystyrene-polyisoprene block-polystyrene), styrene-propylene-based copolymer [SEP (polystyrene- (ethylene / propylene) block], SEPS (polystyrene-poly (ethylene / propylene) block-polystyrene), SEEPS ( Polystyrene-poly (ethylene-ethylene / propylene) block-polystyrene), SEB (polystyrene (ethylene / butylene) block)] and the like.

Commercially available polystyrene-based thermoplastic elastomers include, for example, "ToughTech" series manufactured by Asahi Kasei Corporation (for example, H1031, H1041, H1043, H1051, H1052, H1053, H1062, H1082, H1141, H1221, H1272, etc.). "SEBS" series (8007, 8076, etc.) and "SEPS" series (2002, 2063, etc.) manufactured by Kuraray Co., Ltd. can be used.

(Polyurethane-based thermoplastic elastomer)
As a polyurethane-based thermoplastic elastomer, for example, at least polyurethane forms a hard segment in which pseudo-crosslinking is formed by physical aggregation, and another polymer forms a soft segment having an amorphous and low glass transition temperature. Materials.
Specific examples of the polyurethane-based thermoplastic elastomer include a polyurethane-based thermoplastic elastomer (TPU) specified in JIS K6418: 2007. The polyurethane-based thermoplastic elastomer can be represented as a copolymer including a soft segment containing a unit structure represented by the following formula A and a hard segment containing a unit structure represented by the following formula B.

中 In the formula, P represents a long-chain aliphatic polyether or a long-chain aliphatic polyester. R represents an aliphatic hydrocarbon, an alicyclic hydrocarbon, or an aromatic hydrocarbon. P 'represents a short-chain aliphatic hydrocarbon, an alicyclic hydrocarbon, or an aromatic hydrocarbon.

In Formula A, as the long-chain aliphatic polyether or long-chain aliphatic polyester represented by P, for example, those having a molecular weight of 500 to 5,000 can be used. P is derived from a diol compound containing a long-chain aliphatic polyether represented by P and a long-chain aliphatic polyester. Examples of such a diol compound include polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, poly (butylene adipate) diol, poly-ε-caprolactone diol, and poly (hexamethylene carbonate) having a molecular weight within the above range. Diols and ABA-type triblock polyethers.
These can be used alone or in combination of two or more.

In Formulas A and B, R is a partial structure introduced using a diisocyanate compound containing an aliphatic hydrocarbon, an alicyclic hydrocarbon, or an aromatic hydrocarbon represented by R. Examples of the aliphatic diisocyanate compound containing an aliphatic hydrocarbon represented by R include 1,2-ethylene diisocyanate, 1,3-propylene diisocyanate, 1,4-butane diisocyanate, and 1,6-hexamethylene diisocyanate. No.
Examples of the diisocyanate compound containing an alicyclic hydrocarbon represented by R include 1,4-cyclohexane diisocyanate and 4,4-cyclohexane diisocyanate. Further, examples of the aromatic diisocyanate compound containing an aromatic hydrocarbon represented by R include 4,4′-diphenylmethane diisocyanate and tolylene diisocyanate.
These can be used alone or in combination of two or more.

In Formula B, as the short-chain aliphatic hydrocarbon, alicyclic hydrocarbon, or aromatic hydrocarbon represented by P ′, for example, those having a molecular weight of less than 500 can be used. P ′ is derived from a diol compound containing a short-chain aliphatic hydrocarbon, alicyclic hydrocarbon, or aromatic hydrocarbon represented by P ′. Examples of the aliphatic diol compound containing a short-chain aliphatic hydrocarbon represented by P ′ include glycol and polyalkylene glycol, and specifically, ethylene glycol, propylene glycol, trimethylene glycol, 1,4 -Butanediol, 1,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10- Decanediol and the like.
Examples of the alicyclic diol compound containing an alicyclic hydrocarbon represented by P ′ include cyclopentane-1,2-diol, cyclohexane-1,2-diol, cyclohexane-1,3-diol, Cyclohexane-1,4-diol, cyclohexane-1,4-dimethanol and the like can be mentioned.
Further, examples of the aromatic diol compound containing an aromatic hydrocarbon represented by P ′ include hydroquinone, resorcin, chlorohydroquinone, bromohydroquinone, methylhydroquinone, phenylhydroquinone, methoxyhydroquinone, phenoxyhydroquinone, 4,4′- Dihydroxybiphenyl, 4,4'-dihydroxydiphenylether, 4,4'-dihydroxydiphenylsulfide, 4,4'-dihydroxydiphenylsulfone, 4,4'-dihydroxybenzophenone, 4,4'-dihydroxydiphenylmethane, bisphenol A, 1, Examples thereof include 1-di (4-hydroxyphenyl) cyclohexane, 1,2-bis (4-hydroxyphenoxy) ethane, 1,4-dihydroxynaphthalene, and 2,6-dihydroxynaphthalene.
These can be used alone or in combination of two or more.

ポ リ マ ー The number average molecular weight of the polymer (polyurethane) forming the hard segment is preferably from 300 to 1500 from the viewpoint of melt moldability. The number average molecular weight of the polymer forming the soft segment is preferably from 500 to 20,000, more preferably from 500 to 5,000, particularly preferably from 500 to 3,000, from the viewpoint of the flexibility and thermal stability of the polyurethane thermoplastic elastomer. . The mass ratio (x: y) of the hard segment (x) to the soft segment (y) is preferably from 15:85 to 90:10, and more preferably from 30:70 to 90:10 from the viewpoint of moldability. .

The polyurethane-based thermoplastic elastomer can be synthesized by copolymerizing a polymer forming a hard segment and a polymer forming a soft segment by a known method. As the polyurethane-based thermoplastic elastomer, for example, the thermoplastic polyurethane described in JP-A-5-331256 can be used.

As the polyurethane-based thermoplastic elastomer, specifically, a combination of a hard segment composed of an aromatic diol and an aromatic diisocyanate and a soft segment composed of a polycarbonate is preferable. More specifically, tolylene diisocyanate ( TDI) / polyester-based polyol copolymer, TDI / polyether-based polyol copolymer, TDI / caprolactone-based polyol copolymer, TDI / polycarbonate-based polyol copolymer, 4,4′-diphenylmethane diisocyanate (MDI) / polyester -Based polyol copolymer, MDI / polyether-based polyol copolymer, MDI / caprolactone-based polyol copolymer, MDI / polycarbonate-based polyol copolymer, and MDI + hydroquinone / polyhexamethyl At least one selected from the group consisting of carbonate copolymers is preferred, and TDI / polyester polyol copolymer, TDI / polyether polyol copolymer, MDI / polyester polyol copolymer, MDI / polyether polyol At least one selected from the group consisting of a copolymer and MDI + hydroquinone / polyhexamethylene carbonate copolymer is more preferred.

Examples of commercially available polyurethane-based thermoplastic elastomers include, for example, “Elastoran” series manufactured by BASF (eg, ET680, ET880, ET690, ET890, etc.), and “Kuramilon U” series manufactured by Kuraray Co., Ltd. (for example, , 2000s, 3000s, 8000s, 9000s, etc.), "Milactran" series manufactured by Nippon Miractran Co., Ltd. (for example, XN-2001, XN-2004, P390RSUP, P480RSUI, P26MRNAT, E490, E590, P890, etc.) Etc. can be used.

(Polyolefin thermoplastic elastomer)
As a polyolefin-based thermoplastic elastomer, for example, at least polyolefin forms a hard segment having a high melting point which is crystalline, and another polymer (eg, polyolefin, other polyolefin, polyvinyl compound, etc.) is amorphous and has a glass transition temperature. Materials that form a low soft segment are included. Examples of the polyolefin forming the hard segment include polyethylene, polypropylene, isotactic polypropylene, and polybutene.

Examples of the polyolefin-based thermoplastic elastomer include an olefin-α-olefin random copolymer, an olefin block copolymer and the like. Specifically, a propylene block copolymer, an ethylene-propylene copolymer, a propylene- 1-hexene copolymer, propylene-4-methyl-1-pentene copolymer, propylene-1-butene copolymer, ethylene-1-hexene copolymer, ethylene-4-methyl-pentene copolymer, ethylene- 1-butene copolymer, 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 Copolymer, ethylene-ethyl acrylate copolymer, ethylene-butyl acrylate copolymer, propylene-methacrylic acid copolymer, propylene-methyl methacrylate copolymer, propylene-ethyl methacrylate copolymer, propylene-butyl methacrylate copolymer Examples include a polymer, a propylene-methyl acrylate copolymer, a propylene-ethyl acrylate copolymer, a propylene-butyl acrylate copolymer, an ethylene-vinyl acetate copolymer, a propylene-vinyl acetate copolymer, and the like.

Among them, polyolefin-based thermoplastic elastomers include propylene block copolymers, ethylene-propylene copolymers, propylene-1-hexene copolymers, propylene-4-methyl-1-pentene copolymers, and propylene-1-propylene. Butene copolymer, ethylene-1-hexene copolymer, ethylene-4-methyl-pentene copolymer, ethylene-1-butene copolymer, ethylene-methacrylic acid copolymer, ethylene-methyl methacrylate copolymer , Ethylene-ethyl methacrylate copolymer, ethylene-butyl methacrylate copolymer, ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-butyl acrylate copolymer, propylene-methacrylic acid copolymer , A propylene-methyl methacrylate copolymer, Propylene-ethyl methacrylate copolymer, propylene-butyl methacrylate copolymer, propylene-methyl acrylate copolymer, propylene-ethyl acrylate copolymer, propylene-butyl acrylate copolymer, ethylene-vinyl acetate copolymer, And at least one member selected from the group consisting of propylene-vinyl acetate copolymer, and ethylene-propylene copolymer, propylene-1-butene copolymer, ethylene-1-butene copolymer, ethylene-methyl methacrylate At least one selected from the group consisting of a copolymer, an ethylene-methyl acrylate copolymer, an ethylene-ethyl acrylate copolymer, and an ethylene-butyl acrylate copolymer is more preferable.
Further, two or more olefin resins such as ethylene and propylene may be used in combination. Further, the olefin resin content in the polyolefin-based thermoplastic elastomer is preferably from 50% by mass to 100% by mass.

The number average molecular weight of the polyolefin-based thermoplastic elastomer is preferably from 5,000 to 100,000,000. When the number average molecular weight of the polyolefin-based thermoplastic elastomer is 5,000 to 100,000,000, the mechanical properties of the thermoplastic resin material are sufficient and the workability is excellent. From the same viewpoint, the number average molecular weight of the polyolefin-based thermoplastic elastomer is more preferably from 7,000 to 1,000,000, and particularly preferably from 10,000 to 1,000,000. Thereby, the mechanical properties and workability of the thermoplastic resin material can be further improved. The number average molecular weight of the polymer forming the soft segment is preferably from 200 to 6000 from the viewpoint of toughness and flexibility at low temperature. Further, the mass ratio (x: y) to the hard segment (x) and the soft segment (y) is preferably from 50:50 to 95:15, more preferably from 50:50 to 90:10 from the viewpoint of moldability. .
The polyolefin-based thermoplastic elastomer can be synthesized by copolymerization according to a known method.

Further, as the polyolefin-based thermoplastic elastomer, an elastomer obtained by acid-modifying a polyolefin-based thermoplastic elastomer may be used.
The term "obtained by acid-modifying a polyolefin-based thermoplastic elastomer" refers to a product obtained by bonding an unsaturated compound having an acidic group such as a carboxylic acid group, a sulfuric acid group, or a phosphoric acid group to a polyolefin-based thermoplastic elastomer.
Polyolefin-based thermoplastic elastomer, carboxylic acid group, sulfuric acid group, as to bond an unsaturated compound having an acidic group such as a phosphoric acid group, for example, to a polyolefin-based thermoplastic elastomer, as an unsaturated compound having an acidic group, Bonding (for example, graft polymerization) the unsaturated bond site of an unsaturated carboxylic acid (generally maleic anhydride).
As the unsaturated compound having an acidic group, an unsaturated compound having a carboxylic acid group which is a weak acid group is preferable from the viewpoint of suppressing deterioration of the polyolefin-based thermoplastic elastomer. Examples of the unsaturated compound having a carboxylic acid group include acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, and maleic acid.

Commercially available polyolefin-based thermoplastic elastomers include, for example, "Tuffmer" series manufactured by Mitsui Chemicals, Inc. (for example, A0550S, A1050S, A4050S, A1070S, A4070S, A35070S, A1085S, A4085S, A7090, A70090, MH7007, MH7010). XM-7070, XM-7080, BL4000, BL2481, BL3110, BL3450, P-0275, P-0375, P-0775, P-0180, P-0280, P-0480, P-0680, etc.), Mitsui / Dupont "Nucrel" series manufactured by Polychemical Corporation (for example, AN4214C, AN4225C, AN42115C, N0903HC, N0908C, AN42012C, N410, N1050H, N11 8C, N1110H, N1207C, N1214, AN4221C, N1525, N1560, N0200H, AN4228C, AN4213C, N035C, etc., and "Elvaloy AC" series (for example, 1125AC, 1209AC, 1218AC, 1609AC, 1820AC, 1913AC, 2112AC, 2116AC, 2615AC). 2715AC, 3117AC, 3427AC, 3717AC, etc.), Sumitomo Chemical's "Acrift" series, "Evatate" series, etc., Tosoh Corporation's "Ultracene" series, etc., Prime Polymer's "Prime TPO" series ( For example, E-2900H, F-3900H, E-2900, F-3900, J-5900, E-2910, F-3910, J-5910, E-2710 F-3710, J-5910, E-2740, F-3740, R110MP, R110E, can be used T310E, also M142E, etc.) and the like.

-Thermoplastic resin-
(Polyester thermoplastic resin)
Examples of the polyester-based thermoplastic resin include polyesters forming hard segments of the above-mentioned polyester-based thermoplastic elastomers.
Specific examples of the polyester-based thermoplastic resin include polylactic acid, polyhydroxy-3-butylbutyric acid, polyhydroxy-3-hexylbutyric acid, poly (ε-caprolactone), polyenantholactone, polycaprylolactone, and polybutylene. Examples thereof include aliphatic polyesters such as adipate and polyethylene adipate, and aromatic polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate. Among these, polybutylene terephthalate is preferred as the polyester-based thermoplastic resin from the viewpoint of heat resistance and processability.

Commercially available polyester-based thermoplastic resins include, for example, "Duranex" series (for example, 2000 and 2002) manufactured by Polyplastics Co., Ltd., and "Novaduran" series (for example, 5010R5) manufactured by Mitsubishi Engineering-Plastics Corporation. , 5010R3-2, etc.) and “Toraycon” series manufactured by Toray Industries (eg, 1401X06, 1401X31, etc.).

(Polyamide-based thermoplastic resin)
Examples of the polyamide-based thermoplastic resin include polyamides forming hard segments of the above-described polyamide-based thermoplastic elastomer.
Specific examples of the polyamide-based thermoplastic resin include polyamide (amide 6) obtained by ring-opening polycondensation of ε-caprolactam, polyamide (amide 11) obtained by ring-opening polycondensation of undecane lactam, and ring-opening polycondensation of lauryl lactam. Examples thereof include polyamide (amide 12), polyamide (amide 66) obtained by polycondensation of diamine and dibasic acid, and polyamide (amide MX) having metaxylenediamine as a constituent unit.

Amide 6 can be represented, for example, by {CO— (CH ₂ ) ₅ —NH} _n . The amide 11 can be represented, for example, by {CO— (CH ₂ ) ₁₀ —NH} _n . The amide 12 can be represented, for example, by {CO— (CH ₂ ) ₁₁ —NH} _n . The amide 66 can be represented, for example, by {CO (CH ₂ ) ₄ CONH (CH ₂ ) ₆ NH} _n . Amide MX can be represented, for example, by the following structural formula (A-1). Here, n represents the number of repeating units.

 

As a commercially available product of amide 6, for example, the "UBE nylon" series (for example, 1022B, 1011FB, etc.) manufactured by Ube Industries, Ltd. can be used. As a commercially available amide 11, for example, "Rilsan @ B" series manufactured by Arkema Corporation can be used. As a commercially available product of the amide 12, for example, the "UBE nylon" series (for example, 3024U, 3020U, 3014U, etc.) manufactured by Ube Industries, Ltd. can be used. As a commercially available amide 66, for example, the "Leona" series (for example, 1300S, 1700S, etc.) manufactured by Asahi Kasei Corporation can be used. As a commercially available amide MX, for example, "MX Nylon" series (for example, S6001, S6021, S6011, etc.) manufactured by Mitsubishi Gas Chemical Co., Ltd. can be used.

(4) The polyamide-based thermoplastic resin may be a homopolymer formed of only the above-mentioned constituent units, or a copolymer of the above-mentioned constituent units and another monomer. In the case of a copolymer, the content of the above structural unit in each polyamide-based thermoplastic resin is preferably 40% by mass or more.

(Polyolefin thermoplastic resin)
Examples of the polyolefin-based thermoplastic resin include polyolefins that form the hard segments of the aforementioned polyolefin-based thermoplastic elastomer.
Specific examples of the polyolefin-based thermoplastic resin include a polyethylene-based thermoplastic resin, a polypropylene-based thermoplastic resin, and a polybutadiene-based thermoplastic resin. Among them, a polypropylene-based thermoplastic resin is preferable as the polyolefin-based thermoplastic resin from the viewpoint of heat resistance and workability.
Specific examples of the polypropylene-based thermoplastic resin include a propylene homopolymer, a propylene-α-olefin random copolymer, and a propylene-α-olefin block copolymer. Examples of the α-olefin include propylene, 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 4-methyl-1-pentene, 3-methyl-1-pentene, 1-heptene, Α-olefins having about 3 to 20 carbon atoms, such as 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene.

The first coating resin layer may use a thermoplastic resin and a thermoplastic elastomer alone or in combination of two or more.

The first coating resin layer may contain other components in addition to the resin. Other components include rubber, various fillers (eg, silica, calcium carbonate, clay, etc.), antioxidants, oils, plasticizers, coloring agents, weathering agents, and the like.

[Second coating resin layer]
As the material of the second coating resin layer, a material that satisfies the requirement (condition (A1)) of the water permeability A described above is used.

The second coating resin layer contains a resin. In addition, as a method of controlling the water permeability A of the second coating resin layer to a range that satisfies the condition (A1), a method of selecting the type of the resin in the second coating resin layer, adjusting the content of the resin, and the like. Method.

樹脂 As the resin contained in the second coating resin layer, those listed as the resin contained in the first coating resin layer are similarly used. Further, the kind of the preferable resin, the preferable content, other components that may be included, and the like are the same as in the first coating resin layer.

[Bead filler]
The tire may have a bead filler extending outward from the second coating resin layer in the tire radial direction in the bead portion. In addition, the bead filler may be a single member integrally formed with the second coating resin layer.

材質 The material of the bead filler is not particularly limited, and a conventionally known elastic material such as resin or rubber is used. The bead filler preferably contains a resin as an elastic material, and for example, those listed as the resin contained in the first coating resin layer are similarly used. Further, the kind of the preferable resin, the preferable content, other components that may be included, and the like are the same as in the first coating resin layer.

[Method of forming bead portion]
Here, a method of forming a bead portion in the tire will be described with an example. Specifically, the formation method will be described using the bead portion having the configuration shown in FIG. 2A as an example.

FIG. 2A is a cross-sectional view showing a cross section orthogonal to the circumferential direction (longitudinal direction of bead wire 111) of bead portion 110 having a plurality of bead wires 111. FIG. 2A shows a bead portion 110 in which three bead wires 111 are arranged in parallel and stacked in three stages, that is, in an embodiment having nine bead wires 111. Here, “arranged in parallel” means that a plurality of bead wires 111 have a positional relationship such that they do not intersect in a bead portion 110 cut to a length necessary for application to a tire.
Each bead wire 111 is covered with an adhesive layer 112, and the periphery of the bead wire 111 and the adhesive layer 112 is covered with a first covering resin layer 113 to form a bead core 101. Further, a second coating resin layer 114 covering the periphery of the bead core 101 is provided. In addition, it has a bead filler 103 extending outward from the second coating resin layer 114 in the tire radial direction.

Formation of Adhesive Layer and First Coating Resin Layer The bead core 101 in the bead portion 110 shown in FIG. 2A first covers the periphery of the bead wire 111 with the adhesive layer 112, and then three bead wires covered with the adhesive layer 112 A strip member is formed by covering 111 with the first coating resin layer 113. The bead core 101 is formed by winding this strip member and laminating three stages of strip members having a substantially rectangular cross section.

In FIG. 2A, the number of the bead wires 111 in the bead core 101 is nine, but is not limited to this, and the number of the bead wires 111 may be one or more. For example, as shown in FIG. 1A, an embodiment having only one bead wire 11 may be employed. Further, FIG. 2A shows a mode in which the strip members are stacked in three stages in cross section, but the present invention is not limited to this. For example, one or two stages or four or more stages are stacked. Good.

In the present embodiment, a material (for example, an adhesive) for forming the adhesive layer 112 in the molten state is coated on the outer peripheral surface of the bead wire 111, and the first coating resin layer in the molten state is further applied to the surface of the material for forming the adhesive layer 112. A strip member is formed by coating a material (for example, a resin) forming 113 and solidifying it by cooling. The cross-sectional shape of the strip member (the cross-sectional shape orthogonal to the longitudinal direction of the bead wire 111) is substantially rectangular in the present embodiment, but is not limited thereto, and may be various shapes such as a substantially parallelogram. it can. The formation of the adhesive layer 112 and the formation of the first coating resin layer 113 can be performed by a known method, for example, a method such as extrusion molding. The bead core 101 can be formed by winding and stacking strip members, and the steps are joined by melting the first coating resin layer 113 by a known method such as hot plate welding. And solidifying the melted first coating resin layer 113. Alternatively, the steps can be joined by bonding the steps with an adhesive or the like.

-Formation of second coating resin layer Next, the surface of the obtained bead core 101 is coated with a material (for example, resin) for forming the second coating resin layer 114 in a molten state, and is solidified by cooling, thereby forming the second. The coating resin layer 114 is formed. The formation of the second coating resin layer 114 can be performed by a known method, for example, a method such as injection molding.
Specifically, the bead core 101 is arranged in the cavity of the injection mold, and a material for forming the second coating resin layer 114 in a molten state is injected into the cavity. Next, the second coating resin layer 114 is formed by solidifying the injected material by cooling.

-Formation of Bead Filler The bead part 110 shown in FIG. 2A has a structure in which the bead filler 103 is arranged outward of the second coating resin layer 114 in the tire radial direction. The bead filler 103 can be formed by a known method. For example, when the bead filler 103 is formed of a resin, a method such as injection molding can be used. When the bead filler 103 is the same member integrally formed with the second coating resin layer 114, the bead filler 103 and the second coating resin layer 114 are once molded using an injection molding die. The two members can also be integrally molded by injection of the same.

Next, the configuration of the tire having the above-described bead portion will be described with reference to the drawings using examples.

FIG. 3 is a cross-sectional view in the tire width direction showing a half portion in the tire width direction of an example of the tire 20 having the bead portions 110 shown in FIG. 2A as a pair of bead portions. FIG. 3 shows only a half of the tire 20 in the tire width direction with the equator plane CL as a boundary, but the other half (not shown) has the same configuration. The tire 20 shown in FIG. 3 has a bead portion 110 shown in FIG. 2A embedded in a pair of bead portions, a carcass 16 straddling the bead portion 110 in a toroidal shape, and two belt layers on a radially outer side of the carcass 16 in the tire radial direction. And a belt 17 made of.

Here, the tire width direction refers to a direction parallel to the rotation axis of the tire 20, and is also referred to as a tire axial direction. The tire radial direction refers to a direction orthogonal to the rotation axis of the tire 20. Reference symbol CL indicates an equatorial plane of the tire 20.
Further, in this specification, the rotation axis side of the tire 20 along the tire radial direction is referred to as “inside in the tire radial direction”, and the side opposite to the rotation axis of the tire 20 along the tire radial direction is referred to as “outside in the tire radial direction”. I do. On the other hand, the tire equatorial plane CL side along the tire width direction is described as “inside in the tire width direction”, and the side opposite to the tire equatorial plane CL along the tire width direction is described as “outside in the tire width direction”.

FIG. 3 shows the tire 20 when mounted on a standard rim (not shown) and filled with standard air pressure. Here, the standard rim refers to a standard rim in an applicable size described in the Year @ Book 2017 edition of JATMA (Japan Automobile Tire Association). The standard air pressure is an air pressure corresponding to the maximum load capacity of JATMA's Year Book 2017 version.

In the following description, the load is the maximum load (maximum load capacity) of a single wheel in the applicable size described in the following standard, and the internal pressure is the maximum load of a single wheel described in the following standard The rim refers to a standard rim (or “Approved @ Rim” or “Recommended @ Rim”) in an applicable size described in the following standard. The standards are determined by industry standards that are in effect in the area where the tire is manufactured or used. For example, in the United States, "The Book of the Tire and Rim Association of Inc., Year Book", in Europe, "The European, Tire and Rim, Technical, Organization, Standards of Automotive, Japan Association of Automobiles, Japan Motor Company, Japan Association of Motorcycles, Japan Association of Motorcycles, Japan Motor Company, Korea, Japan, Japan. Have been.

The tire 20 shown in FIG. 3 has a flatness of 55 or more, and has a tire section height (tire section height) of 115 mm or more. Here, the section height (tire section height) refers to a half length of a difference between a tire outer diameter and a rim diameter in a state where the tire 20 is mounted on a standard rim and an internal pressure is set to a standard air pressure. . Further, in the present embodiment, the flatness of the tire 20 is set to 55 or more and the tire section height is set to 115 mm or more, but the present embodiment is not limited to this configuration.

As shown in FIG. 3, the tire 20 includes a pair of left and right bead parts 110 (only one bead part 110 is shown in FIG. 3) and a pair of tire side parts extending outward from the pair of bead parts 110 in the tire radial direction. And a tread portion 19 extending from one tire side portion 18 to the other tire side portion 18.

As shown in FIG. 3, a bead core is embedded in each of the pair of bead portions 110, and the carcass 16 straddles the pair of bead cores. The end of the carcass 16 is locked to a bead core. The end of the carcass 16 is folded back from the inside of the tire to the outside around the bead core and is locked. In the present embodiment, the end of the carcass 16 is arranged in a range (region) corresponding to the tire side portion 18, but the present embodiment is not limited to this configuration. For example, the end of the carcass 16 may be arranged in a range corresponding to the tread portion 19, particularly in a range corresponding to the belt 17.

The carcass 16 extends from one bead core to the other bead core in a toroidal manner to form the skeleton of the tire 20.

A plurality (two layers in this embodiment) of belts 17 are provided outside the carcass in the tire radial direction. A cap layer may be provided on the outside of the belt 17 in the tire radial direction so as to cover the entire belt 17, and further on both sides of the cap layer in the tire radial direction, both ends of the cap layer may be covered. Thus, a pair of layer layers may be provided. Note that the present embodiment is not limited to the above configuration, and may be configured to cover only one end of the cap layer with a layer layer, or to cover both end portions of the cap layer with one layer layer continuous in the tire width direction. It may be. Further, the cap layer and the layer layer may be omitted according to the specifications of the tire 20.
The carcass 16, the belt 17, the cap layer, and the layer layer may have the structure of each member used in a conventionally known tire.

In the tread portion 19, a tread is provided outside the belt 17 in the tire radial direction. The tread is a part that contacts the road surface during traveling. A circumferential groove extending in the tire circumferential direction may be formed on the tread surface of the tread, and a width groove extending in the tire width direction may be formed on the tread. The shape and number of the circumferential grooves and the width grooves are appropriately set in accordance with the required performance of the tire 20 such as drainage and steering stability.

The bead filler 110 is embedded in the bead portion 110 and extends along the outer surface of the carcass 16 from the bead core outward in the tire radial direction. The bead filler is arranged in a region surrounded by the carcass 16 and the folded portion. Further, the thickness of the bead filler decreases outward in the tire radial direction.

高 The height of the bead filler shown in FIG. 3 is preferably set within a range of 30 to 50% of the tire cross-section height. The height of the bead filler referred to here is the height from the tire radial outer end to the tip of the bead portion 110 when the tire 20 is mounted on a standard rim and the internal pressure is set to the standard air pressure (the tire (Length along the radial direction). Here, when the height of the bead filler is 30% or more of the tire cross-sectional height, for example, durability during running can be sufficiently ensured. Further, since the height BH of the bead filler is 50% or less of the tire cross-section height SH, the ride comfort is excellent.

In addition, in the present embodiment, the end of the bead filler is disposed inside the tire 20 in the tire radial direction from the maximum width position of the tire 20. Here, the maximum width position of the tire 20 refers to a position where the width is widest along the tire width direction of the tire 20.

An inner liner (not shown) is provided on the inner surface of the tire 20 from one bead portion 110 to the other bead portion 110. As a main component of the inner liner, a known rubber material and resin (for example, butyl rubber) are used.

-Material The tire 20 shown in Fig. 3 is mainly composed of an elastic material. That is, the region around the carcass 16 in the bead portion 110, the region around the carcass 16 in the tire side portion 18, the region around the belt 17 in the tread portion 19, and the like are made of an elastic material.

Examples of the elastic material include a rubber material (a tire mainly composed of a rubber material is a so-called rubber tire) and a resin material (a tire mainly composed of a resin material is a so-called resin tire).
In particular, in the tire 20 shown in FIG. 3, it is preferable that each of the above-described parts is a rubber tire made of a rubber material.

(Elastic material: rubber material)
The rubber material only needs to contain at least rubber (rubber component), and may contain other components such as additives as long as the effects of the present embodiment are not impaired. However, the content of the rubber (rubber component) in the rubber material is preferably 50% by mass or more, more preferably 90% by mass or more, based on the total amount of the rubber material.

The rubber component used in the tire is not particularly limited, and natural rubber and various synthetic rubbers conventionally used in rubber compounding can be used alone or in combination of two or more. For example, a rubber as shown below, or a rubber blend of two or more of these rubbers can be used.
The natural rubber may be a sheet rubber or a block rubber, and all of RSS # 1 to # 5 can be used.
Examples of the synthetic rubber include various diene-based synthetic rubbers, diene-based copolymer rubbers, special rubbers, and modified rubbers. Specific examples of the synthetic rubber include, for example, butadiene (BR), a copolymer of butadiene and an aromatic vinyl compound (for example, SBR and NBR), and a butadiene-based copolymer such as a copolymer of butadiene and another diene-based compound. Polymers: Isoprene-based polymers such as polyisoprene (IR), copolymers of isoprene and aromatic vinyl compounds, and copolymers of isoprene and other diene compounds; chloroprene rubber (CR), butyl rubber (IIR) And halogenated butyl rubber (X-IIR); ethylene-propylene-based copolymer rubber (EPM), ethylene-propylene-diene-based copolymer rubber (EPDM), and any blends thereof.

Further, the rubber material used for the tire may include other components such as an additive added to the rubber according to the purpose.
Examples of the additive include a reinforcing material such as carbon black, a filler, a vulcanizing agent, a vulcanization accelerator, a fatty acid or a salt thereof, a metal oxide, a process oil, an antioxidant, and the like. can do.

タ イ ヤ A tire mainly composed of a rubber material is obtained by molding an unvulcanized rubber material into a tire shape and vulcanizing the unvulcanized rubber by heating.

(Elastic material: resin material)
The resin material only needs to contain at least the resin (resin component), and may contain other components such as additives as long as the effects of the present embodiment are not impaired. However, the content of the resin (resin component) in the resin material is preferably 50% by mass or more, more preferably 90% by mass or more, based on the total amount of the resin material. The tire frame can be formed using, for example, a resin material.

樹脂 The resin contained in the tire frame includes a thermoplastic resin, a thermoplastic elastomer, and a thermosetting resin.

Examples of the thermosetting resin include a phenol-based thermosetting resin, a urea-based thermosetting resin, a melamine-based thermosetting resin, and an epoxy-based thermosetting resin.
Examples of the thermoplastic resin include a polyamide-based thermoplastic resin, a polyester-based thermoplastic resin, an olefin-based thermoplastic resin, a polyurethane-based thermoplastic resin, a vinyl chloride-based thermoplastic resin, and a polystyrene-based thermoplastic resin. These may be used alone or in combination of two or more. Among them, the thermoplastic resin is preferably at least one selected from the group consisting of a polyamide-based thermoplastic resin, a polyester-based thermoplastic resin, and an olefin-based thermoplastic resin, and is preferably a polyamide-based thermoplastic resin and an olefin-based thermoplastic resin. At least one selected from the group consisting of resins is more preferred.

Examples of the thermoplastic elastomer include a polyamide-based thermoplastic elastomer (TPA), a polystyrene-based thermoplastic elastomer (TPS), a polyurethane-based thermoplastic elastomer (TPU), an olefin-based thermoplastic elastomer (TPO) specified in JIS K6418, Examples thereof include a polyester-based thermoplastic elastomer (TPEE), a crosslinked thermoplastic rubber (TPV), and other thermoplastic elastomers (TPZ).
In consideration of elasticity required during running, moldability during manufacturing, and the like, the resin material forming the tire skeleton should be at least one selected from the group consisting of thermoplastic resins and thermoplastic elastomers. It is more preferable to contain a thermoplastic elastomer from the viewpoint of riding comfort during running. Among them, it is more preferable to include at least one selected from the group consisting of a polyamide-based thermoplastic elastomer and a polyester-based thermoplastic elastomer.

The resin material may contain other components other than the resin, if desired. Other components include, for example, resins, rubbers, various fillers (eg, silica, calcium carbonate, clay), antioxidants, oils, plasticizers, coloring agents, weathering agents, reinforcing materials, and the like.

-Physical properties of elastic material When a resin material is used as the elastic material (that is, in the case of a tire frame for a resin tire), the melting point of the resin contained in the resin material is, for example, about 100 ° C to 350 ° C, and the durability of the tire increases. From the viewpoint of productivity and productivity, the temperature is preferably about 100 ° C. to 250 ° C., and more preferably 120 ° C. to 250 ° C.

The tensile modulus of the elastic material (tire skeleton) itself specified in JIS K7113: 1995 is preferably from 50 MPa to 1000 MPa, more preferably from 50 MPa to 800 MPa, and particularly preferably from 50 MPa to 700 MPa. When the elastic modulus of the elastic material is 50 MPa to 1000 MPa, the rim can be efficiently assembled while maintaining the shape of the tire frame.

The tensile strength of the elastic material (tire frame body) itself specified in JIS K7113 (1995) is usually about 15 MPa to 70 MPa, preferably 17 MPa to 60 MPa, more preferably 20 MPa to 55 MPa.

(4) The tensile yield strength of the elastic material (tire frame) itself as defined in JIS K7113 (1995) is preferably 5 MPa or more, more preferably 5 MPa to 20 MPa, and particularly preferably 5 MPa to 17 MPa. When the tensile yield strength of the elastic material is 5 MPa or more, the elastic material can withstand deformation due to a load applied to the tire during running or the like.

引 張 The tensile yield elongation of the elastic material (tire frame body) itself specified in JIS K7113 (1995) is preferably 10% or more, more preferably 10% to 70%, and particularly preferably 15% to 60%. When the tensile yield elongation of the elastic material is 10% or more, the elastic region is large, and the rim assemblability can be improved.

(5) The tensile elongation at break specified in JIS K7113 (1995) of the elastic material (tire frame) itself is preferably 50% or more, more preferably 100% or more, particularly preferably 150% or more, and most preferably 200% or more. When the tensile elongation at break of the elastic material is 50% or more, the rim assemblability is good, and it is possible to make it difficult to break in a collision.

The deflection temperature under load (under a load of 0.45 MPa) specified by ISO 75-2 or ASTM D648 of the elastic material (tire frame) itself is preferably 50 ° C. or higher, more preferably 50 ° C. to 150 ° C., and more preferably 50 ° C. 130 ° C. is particularly preferred. When the deflection temperature under load of the elastic material is 50 ° C. or more, the deformation of the tire frame can be suppressed even when vulcanization is performed in the manufacture of the tire.

-Manufacture of tire As a method of manufacturing the tire 20, an inner liner (not shown) made of a rubber material, a bead core, a bead filler, and a cord are formed of an elastic material (that is, a rubber material or a resin material) around a known tire forming drum. An unvulcanized tire case is formed having the covered carcass 16, the area around the carcass 16 in the tire side portion 18 formed of an elastic material (that is, a rubber material or a resin material), and the like.

As a method for forming the belt 17 on the tread portion 19 of the tire case, for example, a member such as a wire wound on a reel is unwound while rotating the tire case, and the wire is wound around the tread portion 19 a predetermined number of times. 17 may be formed. When the wire is coated with a resin, the coated resin may be welded to the tread portion 19 by applying heat and pressure.
Finally, an unvulcanized tread is attached to the outer peripheral surface of the belt 17, and a green tire is obtained. The green tire thus manufactured is vulcanized and molded by a vulcanization molding mold, and the tire 20 is completed.

Although the configuration of the tire according to the present embodiment has been described above by way of example, the above-described embodiment is merely an example, and various modifications can be made without departing from the scope of the invention. Needless to say, the scope of rights of the present disclosure is not limited to these embodiments.

Note that an embodiment of the present disclosure includes the following aspects.
<1>
A tire having a pair of bead portions,
At least one of the pair of bead portions has a bead wire, an adhesive layer, a first coating resin layer, and a second coating resin layer in this order,
In a direction where the distance from the surface of the bead wire to the outer surface of the second coating resin layer is minimized in the inward and outward directions in the axial direction of the tire, and in all the inward directions in the radial direction of the tire. The thickness a of the second coating resin layer, the thickness b of the first coating resin layer, and the thickness c of the adhesive layer satisfy the following conditions (a1), (b1), and (c1), respectively. The water permeability A of the second coating resin layer, the water permeability B of the first coating resin layer, and the water permeability C of the adhesive layer are as follows (A1), (B1), and (C1), respectively. A tire that meets the conditions of
(A1) 10 mm ≦ a ≦ 80 mm
(B1) 0.05 mm ≦ b ≦ 0.5 mm
(C1) 0.005 mm ≦ c ≦ 0.1 mm
(A1) A ≦ 300 g · mm / (m ² · day)
(B1) B ≦ 300 g · mm / (m ² · day)
(C1) C ≦ 80 g · mm / (m ² · day)
<2>
The thickness a of the second coating resin layer, the thickness b of the first coating resin layer, and the thickness c of the adhesive layer satisfy the following conditions (a2), (b2), and (c2), respectively. The tire according to <1>.
(A2) 10 mm ≦ a ≦ 50 mm
(B2) 0.05 mm ≦ b ≦ 0.1 mm
(C2) 0.005 mm ≦ c ≦ 0.05 mm
<3>
A ratio of a water permeability A of the second coating resin layer to a water permeability C of the adhesive layer, a ratio of a water permeability B of the first coating resin layer to a water permeability C of the adhesive layer, and <1> or <2>, wherein the ratio of the water permeability A of the second coating resin layer to the water permeability B of the coating resin layer satisfies the following conditions (RA1), (RB1), and (RC1), respectively. The tire described in the above.
(RA1) 2.50 ≦ A / C
(RB1) 1.47 ≦ B / C
(RC1) 0.50 ≦ B / A
<4>
The melt viscosity at 270 ° C. of the second coating resin layer is 150 Pa · s or more and 600 Pa · s or less,
<1> to <3>, wherein the ratio of the melt viscosity Mb at 270 ° C. of the first coating resin layer to the melt viscosity Ma at 270 ° C. of the second coating resin layer satisfies the following condition (Ma1). The tire according to any one of the above.
(Ma1) 0.4 ≦ Mb / Ma ≦ 2.5
<5>
The adhesive layer, the first coating resin layer, and the second coating resin layer are each independently formed of an olefin-based thermoplastic elastomer, an olefin-based thermoplastic resin, a polyamide-based thermoplastic elastomer, a polyamide-based thermoplastic resin, or a polyester-based thermoplastic resin. The tire according to any one of <1> to <4>, including at least one selected from the group consisting of a thermoplastic elastomer and a polyester-based thermoplastic resin.
<6>
The tire according to <5>, wherein the first coating resin layer and the second coating resin layer include a polyester-based thermoplastic elastomer.
<7>
The tire according to <5> or <6>, wherein the adhesive layer includes a polyester-based thermoplastic elastomer.
<8>
The tire according to any one of <1> to <7>, wherein at least one of the adhesive layer, the first coating resin layer, and the second coating resin layer contains an acid-modified thermoplastic material. .
<9>
The tire according to <8>, wherein the adhesive layer includes an acid-modified thermoplastic material.
<10>
The bead wire is a monofilament, and the surface of the monofilament is made of a metal material mainly containing at least one metal element selected from the group consisting of Cu, Zn, Fe, Al, and Co. The tire according to any one of 1> to <9>.

Hereinafter, the present disclosure will be specifically described with reference to examples, but the present disclosure is not limited by these descriptions.

[Examples 1 to 18, Comparative Examples 1 to 11]
<Production of bead member>
As the bead wire, a monofilament (monofilament having an average diameter of 1.25 mm, made of steel, strength: 2700 N, elongation: 7%) is used.

(4) The adhesives shown in Tables 1 to 4 are extruded and adhered to the surface of the bead wire in a state of being melted by heating with an extruder. The conditions for extruding the adhesive layer are as follows: the temperature of the adhesive is 240 ° C.

Next, the bead wire to which the adhesive was adhered was placed in a mold so as to be arranged side by side, and the resin of the first coating resin layer shown in Tables 1 to 4 was extruded by an extruder to obtain a surface of the adhesive. And coated and cooled. In addition, the extrusion conditions of the first coating resin layer are such that the temperature of the resin is 240 ° C. By winding a member in which three bead wires formed in this manner are arranged while being welded by hot air, nine bead wires are respectively covered with an adhesive layer, and the periphery thereof is further covered with a first covering resin layer. A bead core having the bent structure (that is, the structure shown in FIG. 2A) is manufactured. The average distance between adjacent bead wires is 200 μm.

Next, the bead core obtained as described above is placed in a mold previously processed into the shape of the second coating resin layer, and the resin of the second coating resin layer shown in Tables 1 to 4 is injected by an injection molding machine. A member having a structure in which the outer periphery of the bead core is covered with the second coating resin layer (that is, the structure shown in FIG. 2A) is manufactured. The mold temperature during injection molding is 80 ° C., and the molding temperature is 270 ° C.

{Circle around (2)} Using the same resin as that used for the second coating resin layer, the bead filler shown in FIG. 2A is formed by injection molding to produce a bead member.

In addition, regarding the obtained bead member, in all the inward and outward directions in the tire axial direction and the inward direction in the tire radial direction (that is, a specific target direction in this specification), the second coating resin is formed from the surface of the bead wire. Tables 1 to 4 show the thickness a of the second coating resin layer, the thickness b of the first coating resin layer, and the thickness c of the adhesive layer at the point where the distance to the outer surface of the layer becomes minimum. Show. A / C is the ratio of the water permeability A of the second coating resin layer to the water permeability C of the adhesive layer, and the ratio of the water permeability B of the first coating resin layer to the water permeability C of the adhesive layer. Tables 1 to 4 show B / C and B / A, which is the ratio of the water permeability C of the adhesive layer to the water permeability A of the second coating resin layer. The viscosity b / viscosity a, which is the ratio of the melt viscosity Mb at 270 ° C. of the first coating resin layer to the melt viscosity Ma at 270 ° C. of the second coating resin layer, and the viscosity at 270 ° C. of the first coating resin layer Tables 1 to 4 show the viscosity c / viscosity b, which is the ratio of the melt viscosity Mc at 270 ° C. of the adhesive layer to the melt viscosity Mb.

<Production of tire having bead member as bead portion>
The tire of the embodiment shown in FIG. 3 described above is manufactured using the bead member obtained as described above for a pair of bead portions.
A bead member obtained as described above and a carcass made of a ply cord made of polyethylene terephthalate are prepared, and a tire side portion (carcass tire) using a mixed rubber material of natural rubber (NR) and styrene butadiene rubber (SBR) is prepared. A green tire is manufactured using the outer side in the width direction), the side reinforcing rubber, the tread portion, and the belt layer of the stranded wire.
The raw tire to be produced is heated (rubber vulcanization) at 160 ° C. for 21 minutes.
The resulting tire has a tire size of 225 / 40R18 and a tread thickness of 10 mm.

In each of the examples and comparative examples, the details of the resin used for forming the first coating resin layer and the second coating resin layer are as follows.
・ Resin 1
Polyamide-based thermoplastic elastomer (manufactured by Ube Industries, Ltd., trade name “UBESTA XPA9055”), water permeability 140 g · mm / (m ² · day)
・ Resin 2
Polyamide-based thermoplastic elastomer (trade name “UBESTA XPA9048” manufactured by Ube Industries, Ltd.), water permeability 280 g · mm / (m ² · day)
・ Resin 3
Polyamide-based thermoplastic resin (PA6, manufactured by Ube Industries, Ltd., trade name “UBE nylon 1013B”), water permeability 400 g · mm / (m ² · day)
・ Resin 4
Polyester-based thermoplastic elastomer, water permeability 220 g · mm / (m ² · day)
・ Resin 5
Polyester-based thermoplastic elastomer (manufactured by Toyobo Co., Ltd., trade name “Perprene P90B”), water permeability 200 g · mm / (m ² · day)

The details of the adhesive used for forming the adhesive layer in each example and comparative example are as follows.
・ Adhesive 1
Acid-modified polypropylene resin, hot melt adhesive (trade name “Admer QE060”, manufactured by Mitsui Chemicals, Inc.), water permeability 10 g · mm / (m ² · day)
・ Adhesive 2
Acid-modified polypropylene resin, hot melt adhesive (trade name “Admer QF500”, manufactured by Mitsui Chemicals, Inc.), water permeability 5 g · mm / (m ² · day)
・ Adhesive 3
Polypropylene resin (unmodified homo PP, manufactured by Prime Polymer Co., Ltd., trade name "Prime Polypro J-700GP"), water permeability 3 g · mm / (m ² · day)
・ Adhesive 4
Polyamide-based resin, hot melt adhesive (trade name “Platamid B409”, manufactured by Arkema Corporation), water permeability 100 g · mm / (m ² · day)
・ Adhesive 5
Polyamide-based resin, hot melt adhesive (manufactured by Daicel Evonik Co., Ltd., trade name "Daiamide A6492"), water permeability 50 g · mm / (m ² · day)
・ Adhesive 6
Acid-modified polyester-based thermoplastic elastomer, hot melt adhesive, water permeability 150 g · mm / (m ² · day)
・ Adhesive 7
Acid-modified polyester-based thermoplastic elastomer, hot melt adhesive, water permeability 500 g · mm / (m ² · day)
・ Adhesive 8
Acid-modified polyester-based thermoplastic elastomer, hot melt adhesive, water permeability 80 g · mm / (m ² · day)

〔Evaluation test〕
<Hydraulic test>
After assembling the tires manufactured in Examples and Comparative Examples into a rim, water is injected into the tires, and a water pressure value (tire strength) when the tire is broken and a mode of the breaking are compared. The water pressure value is indexed with the value when the tire of Comparative Example 2 is broken as 100, and the adhesiveness is evaluated according to the following evaluation criteria. The higher the value, the better the durability.
-Evaluation criteria-
A Greater than 110.
B is larger than 100 and 110 or less.
C is 100 or less.

<Adhesion test after wet heat deterioration treatment (wet heat deterioration durability test)>
For the bead member before forming the bead filler (that is, the member in which the adhesive layer, the first coating resin layer, and the second coating resin layer are formed on the bead wire) before being formed in Examples and Comparative Examples, Deterioration is performed for 3 weeks at a temperature of 75 ° C. and a humidity of 95%. Thereafter, the peeling force (unit: N) is measured in the same manner as in the method described in the initial adhesion test, and evaluated according to the following evaluation criteria.
-Evaluation criteria-
A: The peeling force after the deterioration treatment is 75% or more of the peeling force immediately after fabrication.
B: The peeling force after the deterioration treatment is 50% or more and less than 75% of the peeling force immediately after production.
C The peel force after the deterioration treatment is less than 50% of the peel force immediately after the production.

<Initial adhesion test>
For the bead member before forming the bead filler (that is, the member in which the adhesive layer, the first coating resin layer, and the second coating resin layer are formed on the bead wire) before being formed in Examples and Comparative Examples, As an index of the adhesiveness between the adhesive layer and the bead wire, a peeling force when the adhesive layer, the first coating resin layer, and the second coating resin layer are peeled off from the bead wire immediately after the production of the above member is measured.
Specifically, a 180 ° peel test was conducted at a tensile speed of 100 mm / min in a room temperature environment (25 ° C.) using “TENSIRON RTF-1210” manufactured by A & D Corporation, and the peel force (unit) was measured. : N), and the adhesiveness is evaluated according to the following evaluation criteria.
-Evaluation criteria-
A The peeling force is 17 N or more.
B The peeling force is 14 N or more and less than 17 N.
C The peeling force is 10 N or more and less than 14 N.
D The peel force is less than 10N.

<JIS drum test after wet heat deterioration treatment>
The tires manufactured in the examples and the comparative examples are filled with air so that the internal pressure becomes 250 kPa, and then subjected to a deterioration treatment for 10 days at a temperature of 75 ° C. and a humidity of 95%. The tire after the deterioration treatment is subjected to a durability drum test as described below, and is evaluated according to the following evaluation criteria.
The tire is adjusted to an internal pressure of 3.0 kg / cm ² in a room at 25 ± 2 ° C., and then left for 24 hours. Thereafter, the air pressure is readjusted, the tire is applied with a load 1.8 times the JIS load, and the tire is run at a speed of 60 km / h at a maximum of 20,000 km on a drum having a diameter of about 3 m. Then, the distance traveled before the tire breaks down is measured and evaluated according to the following evaluation criteria. The longer the traveling distance, the better the durability of the tire, and if it is classified as [A], it can be said that it is practically preferable.
-Evaluation criteria-
A: Complete 20,000 km.
B: The traveling distance until the occurrence of the failure is not less than 10,000 km and less than 20,000 km.
C: The traveling distance until the occurrence of the failure is less than 10,000 km.

 

 

 

 

In the table, “water permeability” is unit = g · mm / (m ² · day), and “viscosity” is unit = Pa · s (measuring temperature 270 ° C.).

With respect to the results of each evaluation test shown in the above table, Examples 1 and 6 are data obtained by actually performing the test, while Examples 2 to 5, 7 to 18 and Comparative Examples 1 to 11 are data. This is prediction data from data obtained by actually performing a test.

As shown in the table, the tires of the examples satisfying the conditions (a1), (b1), (c1), (A1), (B1), and (C1) are of the comparative example that does not satisfy any of the above conditions. A good evaluation is obtained in any of the tests as compared with the tire.

The disclosure of Japanese Patent Application No. 2018-183809 filed on September 28, 2018 is incorporated herein by reference in its entirety.
All documents, patent applications, and technical standards mentioned herein are to the same extent as if each individual document, patent application, and technical standard were specifically and individually stated to be incorporated by reference. Incorporated herein.

1, 101 bead core 3, 103 bead filler 10, 110 bead portion 11, 111 bead wire 12, 112 adhesive layer 13, 113 first coating resin layer 14, 114 second coating resin layer 16 carcass 17 belt 18 tire side portion 19 tread Part 20 Tire CL Equatorial plane

Claims (10)

1. A tire having a pair of bead portions,
   At least one of the pair of bead portions has a bead wire, an adhesive layer, a first coating resin layer, and a second coating resin layer in this order,
   In a direction where the distance from the surface of the bead wire to the outer surface of the second coating resin layer is minimized in the inward and outward directions in the axial direction of the tire, and in all the inward directions in the radial direction of the tire. The thickness a of the second coating resin layer, the thickness b of the first coating resin layer, and the thickness c of the adhesive layer satisfy the following conditions (a1), (b1), and (c1), respectively. The water permeability A of the second coating resin layer, the water permeability B of the first coating resin layer, and the water permeability C of the adhesive layer are as follows (A1), (B1), and (C1), respectively. A tire that meets the conditions of
   (A1) 10 mm ≦ a ≦ 80 mm
   (B1) 0.05 mm ≦ b ≦ 0.5 mm
   (C1) 0.005 mm ≦ c ≦ 0.1 mm
   (A1) A ≦ 300 g · mm / (m ² · day)
   (B1) B ≦ 300 g · mm / (m ² · day)
   (C1) C ≦ 80 g · mm / (m ² · day)
2. The thickness a of the second coating resin layer, the thickness b of the first coating resin layer, and the thickness c of the adhesive layer satisfy the following conditions (a2), (b2), and (c2), respectively. The tire according to claim 1.
   (A2) 10 mm ≦ a ≦ 50 mm
   (B2) 0.05 mm ≦ b ≦ 0.1 mm
   (C2) 0.005 mm ≦ c ≦ 0.05 mm
3. A ratio of a water permeability A of the second coating resin layer to a water permeability C of the adhesive layer, a ratio of a water permeability B of the first coating resin layer to a water permeability C of the adhesive layer, and The ratio of the water permeability A of the second coating resin layer to the water permeability B of the coating resin layer satisfies the following conditions (RA1), (RB1), and (RC1), respectively. The tire described in the above.
   (RA1) 2.50 ≦ A / C
   (RB1) 1.47 ≦ B / C
   (RC1) 0.50 ≦ B / A
4. The melt viscosity at 270 ° C. of the second coating resin layer is 150 Pa · s or more and 600 Pa · s or less,
   And the ratio of the melt viscosity Mb at 270 ° C. of the first coating resin layer to the melt viscosity Ma at 270 ° C. of the second coating resin layer satisfies the following condition (Ma1). A tire according to any one of the preceding claims.
   (Ma1) 0.4 ≦ Mb / Ma ≦ 2.5
5. The adhesive layer, the first coating resin layer, and the second coating resin layer are each independently an olefin-based thermoplastic elastomer, an olefin-based thermoplastic resin, a polyamide-based thermoplastic elastomer, a polyamide-based thermoplastic resin, or a polyester-based thermoplastic elastomer. The tire according to any one of claims 1 to 4, comprising at least one selected from the group consisting of a thermoplastic elastomer and a polyester-based thermoplastic resin.
6. The tire according to claim 5, wherein the first coating resin layer and the second coating resin layer include a polyester-based thermoplastic elastomer.
7. The tire according to claim 5 or 6, wherein the adhesive layer contains a polyester-based thermoplastic elastomer.
8. The tire according to any one of claims 1 to 7, wherein at least one of the adhesive layer, the first coating resin layer, and the second coating resin layer contains an acid-modified thermoplastic material. .
9. The tire according to claim 8, wherein the adhesive layer includes an acid-modified thermoplastic material.
10. The bead wire is a monofilament, and the surface of the monofilament is made of a metal material mainly containing at least one metal element selected from the group consisting of Cu, Zn, Fe, Al, and Co. The tire according to any one of claims 1 to 9.

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