Pneumatic Tire Having Built-In Sealant Layer And Preparation Thereof

• US 20090078352A1
• Filed: 09/20/2007
• Published: 03/26/2009
• Est. Priority Date: 09/20/2007
• Status: Active Grant

• Current Assignee: Goodyear Tire & Rubber Company
• Original Assignee: Goodyear Tire & Rubber Company
• Inventors: Puhala, Aaron Scott, Majumdar, Ramendra Nath
• Granted Patent: US 8,617,333 B2
• Time in Patent Office: Days
• US Class Current: 152/504
• CPC Class Codes: B29C 73/163 Sealing compositions or agents, e.g. combined with propellant agents
• CPC Class Codes: B29C 73/20 the article material only consisting in part of a deformable sealing material
• CPC Class Codes: B29D 2030/069 through the use of a cylindrical support, e.g. a drum
• CPC Class Codes: B29D 2030/0691 through the use of a toroidal support, e.g. a core, a part of the tyre or an inner tube
• CPC Class Codes: B29D 2030/0695 the sealant being in the form of one wide strip, e.g. a patch
• CPC Class Codes: B29D 30/0685 Incorporating auto-repairing or self-sealing arrangements or agents on or into tyres auto-repairing or self-sealing arrangements or agents B29C73/16; puncture preventing arrangements B60C19/12
• CPC Class Codes: B29L 2030/00 Pneumatic or solid tyres or parts thereof conveyor belts B29L2031/7092; drive belts B29L2031/7094; fourdrinier belts B29L2031/733
• CPC Class Codes: B60C 19/12 Puncture preventing arrangements
• CPC Class Codes: Y10T 152/10666 Automatic sealing of punctures [e.g., self-healing, etc.]
• CPC Class Codes: Y10T 152/10675 Using flowable coating or composition
• CPC Class Codes: Y10T 152/10684 On inner surface of tubeless tire

Abstract

In one embodiment, a pneumatic tire having a built-in sealant layer, before cure, includes an unvulcanized pneumatic tire assembly having an outer circumferential rubber tread and a supporting carcass. A precursor sealant layer is situated between the supporting carcass and an innermost rubber inner liner. The precursor sealant layer includes a non-flowing polyurethane composition that is neither gel-like nor tacky and is self-supporting. The precursor sealant layer, during curing of the unvulcanized pneumatic tire assembly, thermally degrades so as to provide a gel-like and tacky, self-healing polyurethane composition which defines the built-in sealant layer. The resulting tire, with its innermost polyurethane composition, allows for elimination or reduction in blister formation by reducing or elimination the amount of gases typically given off by organoperoxide-butyl based sealant layers, such as when the tire is at its running temperature. Consequently, the thickness of the inner liner may be reduced.

Claims

1. An unvulcanized pneumatic tire assembly comprising:

an outer circumferential rubber tread, a supporting carcass therefor, and a precursor sealant layer situated between the supporting carcass and an innermost rubber inner liner defining the unvulcanized pneumatic tire assembly, the precursor sealant layer is self-supporting and includes a non-flowing polyurethane composition that is neither gel-like nor substantially tacky, the precursor sealant layer provides self-sealing properties to a pneumatic tire after vulcanization of the unvulcanized pneumatic tire assembly.

2. The unvulcanized pneumatic tire assembly of claim 1 wherein the polyurethane composition is a polyurethane based material containing methylene diphenyl 4,4′

-diisocyanate (MDI) and poly(alkylene oxide)glycol.

3. The unvulcanized pneumatic tire assembly of claim 2 wherein the polyurethane composition includes a colorant.

4. The unvulcanized pneumatic tire assembly of claim 1 wherein the rubber inner liner is a sulfur curative-containing halobutyl rubber composition of a halobutyl rubber.

5. A method of preparing a pneumatic tire comprising:

positioning a rubber inner liner on a tire-building apparatus;

positioning a precursor sealant layer, which is self-supporting and includes a non-flowing polyurethane composition that is neither gel-like nor tacky, on the rubber inner liner;

disposing outwardly of the precursor sealant layer, a tire carcass followed by a rubber tire tread on the tire carcass to define an unvulcanized tire assembly; and

vulcanizing the unvulcanized tire assembly under conditions of heat and pressure such that the non-flowing polyurethane composition thermally degrades to give a gel-like and tacky polyurethane composition which provides the pneumatic tire with self-sealing properties.

6. The method of claim 5 wherein the polyurethane composition is a polyurethane based material containing methylene diphenyl 4,4′

-diisocyanate (MDI) and poly(alkylene oxide)glycol.

7. The method of claim 5 wherein the polyurethane composition includes a colorant.

8. The method of claim 5 wherein the rubber inner liner is a sulfur curative-containing halobutyl rubber composition of a halobutyl rubber.

9. A pneumatic tire prepared according to the method of claim 5.