PNEUMATIC TIRE AND CROSSLINKED RUBBER COMPOSITION

• US 20180297404A1
• Filed: 10/21/2016
• Published: 10/18/2018
• Est. Priority Date: 10/27/2015
• Status: Active Grant

• Current Assignee: Sumitomo Rubber Industries Limited
• Original Assignee: Sumitomo Rubber Industries Limited
• Inventors: MASHITA, Ryo, KISHIMOTO, Hiroyuki, KITAGO, Ryota
• Granted Patent: US 10,639,932 B2
• Time in Patent Office: Days
• CPC Class Codes: B60C 1/00 Tyres characterised by the chemical composition or the physical arrangement or mixture of the composition
• CPC Class Codes: B60C 1/0016 Compositions of the tread
• CPC Class Codes: B60C 11/00 Tyre tread bands; Tread patterns; Anti-skid inserts
• CPC Class Codes: B60C 11/0008 characterised by the tread rubber
• CPC Class Codes: B60C 2011/0016 Physical properties or dimensions
• CPC Class Codes: B60C 2011/0025 Modulus or tan delta
• CPC Class Codes: C08K 3/36 Silica
• CPC Class Codes: C08L 9/00 Compositions of homopolymers or copolymers of conjugated diene hydrocarbons
• CPC Class Codes: C08L 9/06 Copolymers with styrene
• CPC Class Codes: G01N 15/088 Investigating volume, surface area, size or distribution of pores; Porosimetry
• CPC Class Codes: G01N 2015/0061 in solids, e.g. petrography
• CPC Class Codes: G01N 23/046 using tomography, e.g. computed tomography [CT]
• CPC Class Codes: G01N 23/083 the radiation being X-rays
• CPC Class Codes: G01N 9/24 by observing the transmission of wave or particle radiation through the material

Abstract

The pneumatic tire of the present invention characterized by comprising: bead cores, a carcass ply, an inner liner disposed at an inner side than the carcass ply in a direction of a tire diameter, and a tread disposed at an outer side than the carcass ply in a direction of a tire diameter and having a volume of the low density region of 35% or more at elongation by an applied stress of 1.5 MPa, a volume of the void portion of 7.5% or less at elongation by an applied stress of 3.0 MPa and a filler dispersibility index ΔG* shown by the following equation (I) of 3 or less and the crosslinked rubber composition having a volume of the low density region of 35% or more at elongation by an applied stress of 1.5 MPa, a volume of the void portion of 7.5 or less at elongation by an applied stress of 3.0 MPa and a filler dispersibility index ΔG* shown by the following equation (I) of 3 or less are excellent in abrasion resistance.

ΔG*=(G*(4%)−G*(256%))/G*(256%)  (I)

In the equation (I), G* (n %) indicates a shear modulus when an n % strain is applied.

Claims

1. A pneumatic tire comprising:

bead cores provided on a pair of right and left bead portions, respectively,

a carcass ply extending from a crown portion to the both bead portions through both side wall portions and moored to the bead cores,

an inner liner disposed at an inner side than the carcass ply in a direction of a tire diameter, and

a tread disposed at an outer side than the carcass ply in a direction of a tire diameter and having a volume of the low density region of 35% or more at elongation by an applied stress of 1.5 MPa, a volume of the void portion of 7.5% or less at elongation by an applied stress of 3.0 MPa and a filler dispersibility index Δ

G* shown by the following equation (I) of 3 or less;

Δ

G*=(G*(4%)−

G*(256%))/G*(256%) 

 

(I)

wherein in the equation (I), G* (n %) indicates a shear modulus when an n % strain is applied,

wherein the low density region is a region having a density of 0.1 to 0.8 times the density of a crosslinked rubber composition before the elongation, and

wherein the void portion is a region having a density of 0 to 0.1 times the density of a crosslinked rubber composition before the elongation.

2. A crosslinked rubber composition having a volume of the low density region of 35% or more at elongation by an applied stress of 1.5 MPa, a volume of the void portion of 7.5 or less at elongation by an applied stress of 3.0 MPa and a filler dispersibility index Δ

G* shown by the following equation (I) of 3 or less;

Δ

G*=(G*(4%)−

G*(256%))/G*(256%) 

 

(I)

wherein in the equation (I), G* (n %) indicates a shear modulus when an n % strain is applied,

wherein the low density region is a region having a density of 0.1 to 0.8 times the density of a crosslinked rubber composition before the elongation, and

wherein the void portion is a region having a density of 0 to 0.1 times the density of a crosslinked rubber composition before the elongation.

3. The crosslinked rubber composition of claim 2, wherein the rubber component is a rubber component comprising one or more of rubber components comprising a conjugated diene compound.

4. The crosslinked rubber composition of claim 2, wherein

the volume of the low density region at elongation by an applied stress of 1.5 MPa is 35% or more,

the volume of the void portion at elongation by an applied stress of 3.0 MPa is 7.0% or less, and

the filler dispersibility index Δ

G* is 2.0 or less.

5. The crosslinked rubber composition of claim 2, wherein

the volume of the low density region at elongation by an applied stress of 1.5 MPa is evaluated from a density distribution of the crosslinked rubber composition when extended using an X-ray computerized tomography, and

the volume of the void portion at elongation by an applied stress of 3.0 MPa is evaluated from a density distribution of the crosslinked rubber composition when extended using an X-ray computerized tomography.

6. The crosslinked rubber composition of claim 5, wherein a decay time of a phosphor for converting the X-ray into a visible light is 100 ms or less.

7. The crosslinked rubber composition of claim 5, wherein a luminance of the X-ray is 10¹⁰ photons/s/mrad²/mm²/0.1% bw or more.

8. (canceled)