Pneumatic Tire

Patent metadata

Field	Value
Publication number	US-2018244112-A1
Application number	US-201615553962-A
Country	US
Kind code	A1
Filing date	Feb 24, 2016
Priority date	Feb 27, 2015
Publication date	Aug 30, 2018
Grant date	—

Abstract

Provided is a pneumatic tire which comprises a pair of left and right bead portions, sidewall portions continuous from the bead portions, and a tread portion that couples the sidewall portions. The pneumatic tire has a carcass layer mounted between the left and right bead portions. The sidewall portions each have a foamed rubber layer disposed outside the carcass layer and a side rubber layer disposed outside the foamed rubber layer. The density of the foamed rubber layer is from 0.5 to 0.9 g/cm3 and a tan δ of the foamed rubber layer at 20° C. is not greater than 0.17. A rubber composition for sidewalls that forms the side rubber layer is obtained by blending from 1 to 20 parts by weight of a thermoplastic resin and from 10 to 65 parts by weight of a carbon black in 100 parts by weight of a diene rubber.

First claim

1 . A pneumatic tire, comprising:
a pair of left and right bead portions; sidewall portions continuous from the bead portions; and a tread portion that couples the sidewall portions; wherein the pneumatic tire has a carcass layer mounted between the left and right bead portions, in the pneumatic tire, the sidewall portions each having a foamed rubber layer disposed outside the carcass layer and a side rubber layer disposed outside the foamed rubber layer, a density of the foamed rubber layer is from 0.5 to 0.9 g/cm 3 and a tan δ of the foamed rubber layer at 20° C. is not greater than 0.17, and a rubber composition for sidewalls that forms the side rubber layer is obtained by blending 1 to 20 parts by weight of a thermoplastic resin and 10 to 65 parts by weight of a carbon black in 100 parts by weight of a diene rubber.

2 . The pneumatic tire according to claim 1 , wherein the thermoplastic resin is selected from a polystyrene and a polypropylene.

3 . The pneumatic tire according to claim 1 , wherein a ratio of a volume of the foamed rubber layer to that of the side rubber layer (foamed rubber layer/side rubber layer) is from 1/1 to 10/1.

4 . The pneumatic tire according to claim 1 , wherein the rubber composition for sidewalls contains from 30 to 70 wt. % of natural rubber and from 70 to 30 wt. % of a butadiene rubber and/or a styrene butadiene rubber in 100 wt. % of the diene rubber.

5 . The pneumatic tire according to claim 1 , wherein the foamed rubber layer has a thermal conductivity of from 0.05 to 0.2 W/mK.

6 . The pneumatic tire according to claim 1 , wherein the rubber composition forming the foamed rubber layer contains a nitroso foaming agent and/or an azo foaming agent.

7 . The pneumatic tire according to claim 1 , wherein the rubber composition forming the foamed rubber layer contains from 0.1 to 20 parts by weight of urea in 100 parts by weight of the diene rubber.

8 . The pneumatic tire according to claim 2 , wherein a ratio of a volume of the foamed rubber layer to that of the side rubber layer (foamed rubber layer/side rubber layer) is from 1/1 to 10/1.

9 . The pneumatic tire according to claim 8 , wherein the rubber composition for sidewalls contains from 30 to 70 wt. % of natural rubber and from 70 to 30 wt. % of a butadiene rubber and/or a styrene butadiene rubber in 100 wt. % of the diene rubber.

10 . The pneumatic tire according to claim 9 , wherein the foamed rubber layer has a thermal conductivity of from 0.05 to 0.2 W/mK.

11 . The pneumatic tire according to claim 10 , wherein the rubber composition forming the foamed rubber layer contains a nitroso foaming agent and/or an azo foaming agent.

12 . The pneumatic tire according to claim 11 , wherein the rubber composition forming the foamed rubber layer contains from 0.1 to 20 parts by weight of urea in 100 parts by weight of the diene rubber.

Assignees

• Yokohama Rubber Co Ltd

Inventors

• Sakai Tomoyuki
• Onoi Hidekazu

Classifications

• C09K5/14

  Solid materials, e.g. powdery or granular · CPC title

• C08J9/0066

  Use of inorganic compounding ingredients · CPC title

• C08J9/107

  Nitroso compounds · CPC title

• C08K5/23

  Azo-compounds · CPC title

• B60C2013/005

  Physical properties of the sidewall rubber · CPC title