Inner liner for pneumatic tire and method for producing the same

Patent metadata

Field	Value
Publication number	US-9873238-B2
Application number	US-201013513429-A
Country	US
Kind code	B2
Filing date	Nov 30, 2010
Priority date	Dec 1, 2009
Publication date	Jan 23, 2018
Grant date	Jan 23, 2018

Abstract

Disclosed is an inner liner for a pneumatic tire, the inner liner including no less than 8 resin-layers, the resin-layer having a layer A constituted with a resin composition containing a gas barrier resin, and a layer B constituted with a resin composition containing an elastomer, at least one of the resin compositions included in the layer A and the layer B that are adjacent with each other containing a metal salt, the content of the metal salt being no less than 1 ppm and no greater than 10,000 ppm in terms of metal element equivalent, and an interlayer adhesive force between the layer A and the layer B being no less than 500 g/15 mm. The layer A and the layer B are preferably alternately laminated.

First claim

The invention claimed is:

1. An inner liner, comprising at least 17 resin-layers, the at least 17 resin-layers comprising:
a layer A comprising a resin composition comprising a gas barrier resin, and
a layer B comprising a resin composition comprising an elastomer,
wherein, the layer A and the layer B are alternately laminated in direct contact, a total number of the layer A and the layer B being at least 17 and no greater than 129,
at least one selected from the group consisting of the resin composition in the layer A and the resin composition in the layer B comprises a metal salt,
a content of the metal salt is at least 1 ppm and no greater than 10,000 ppm in terms of metal element equivalent,
an interlayer adhesive force between the layer A and the layer B is at least 1,210 g/15 mm,
an average thickness of the layer A in terms of a single layer is at least 0.01 μm and no greater than 10 μm,
an average thickness of the layer B in terms of a single layer is at least 0.01 μm and no greater than 10 μm,
the gas barrier resin is at least one selected from the group consisting of an ethylene-vinyl alcohol copolymer, a polyamide resin, and a polyester resin,
the elastomer is at least one selected from the group consisting of a polyurethane based elastomer, a polyester based elastomer, a polyamide based elastomer, and a fluorine contained resin based elastomer,
the resin composition of the layer A further comprises a carboxylic acid in an amount of at least 1 ppm and no greater than 10,000 ppm, and
the inner liner is suitable for a pneumatic tire.

2. The inner liner of claim 1 , wherein a thickness of the inner liner is at least 0.1 μm and no greater than 1,000 μm.

3. The inner liner of claim 1 , wherein the metal salt is at least one selected from the group consisting of an alkali metal salt, an alkaline earth metal salt, and a salt of a d-block metal in group 4 of the periodic table.

4. The inner liner of claim 1 , wherein the gas barrier resin is an ethylene-vinyl alcohol copolymer.

5. The inner liner of claim 4 , wherein a content of ethylene units of the ethylene-vinyl alcohol copolymer is at least 3 mol % and no greater than 70 mol %.

6. The inner liner of claim 4 , wherein the ethylene-vinyl alcohol copolymer has a saponification degree of at least 80 mol %.

7. The inner liner of claim 4 ,
wherein the ethylene-vinyl alcohol copolymer comprises at least one selected from the group consisting of structural units (I) and (II):

a content of the structural units (I) or (II) with respect to all structural units is at least 0.5 mol % and no greater than 30 mol %,
R 1 , R 2 , and R 3 are each independently a hydrogen atom, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, an alicyclic hydrocarbon group having 3 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 10 carbon atoms, or a hydroxyl group; with the provisos that two among R 1 , R 2 , and R 3 are optionally bound with one another, unless the two among R 1 , R 2 , and R 3 are both a hydrogen atom; and that any of R 1 , R 2 , and R 3 that is an aliphatic hydrocarbon group having 1 to 10 carbon atoms, an alicyclic hydrocarbon group having 3 to 10 carbon atoms, or an aromatic hydrocarbon group having 6 to 10 carbon atoms optionally has a hydroxyl group, a carboxyl group, or a halogen atom; and
R 4 , R 5 , R 6 and R 7 are each independently a hydrogen atom, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, an alicyclic hydrocarbon group having 3 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 10 carbon atoms, or a hydroxyl group; with the provisos that R 4 and R 5 or R 6 and R 7 are optionally bound with one another, unless both R 4 and R 5 or both R 6 and R 7 are a hydrogen atom; and that any of R 4 , R 5 , R 6 , and R 7 that is an aliphatic hydrocarbon group having 1 to 10 carbon atoms, an alicyclic hydrocarbon group having 3 to 10 carbon atoms, or an aromatic hydrocarbon group having 6 to 10 carbon atoms optionally has a hydroxyl group, an alkoxy group, a carboxyl group, or a halogen atom.

8. The inner liner of claim 1 , wherein the resin composition of the layer A further comprises a phosphate compound in an amount of at least 1 ppm and no greater than 10,000 ppm in terms of phosphoric acid group equivalent.

9. The inner liner of claim 1 , wherein the resin composition of the layer A further comprises a boron compound in an amount of at least 1 ppm and no greater than 2,000 ppm in terms of boron equivalent.

10. The inner liner of claim 1 , wherein the resin composition of the layer A, the resin composition of the layer B, or both has:
a melt viscosity (η 1 ), as determined at a temperature of 210° C. and a shear rate of 10/sec, of at least 1×10 2 Pa·s and no greater than 1×10 4 Pa·s,
a melt viscosity (η 2 ), as determined at a temperature of 210° C. and a shear rate of 1,000/sec, of at least 1×10 1 Pa·s and no greater than 1×10 3 Pa·s, and
a ratio (η 2 /η 1 ) of the melt viscosities satisfies formula (1):
−0.8≦(½)log 10 (η 2 /η 1 )≦−0.1  (1).

11. The inner liner of claim 1 ,
wherein a ratio (η 2B /η 2A ) of a melt viscosity (η 2B ) of the resin composition of the layer B to a melt viscosity (η 2A ) of the resin composition of the layer A as determined at a temperature of 210° C. and a shear rate of 1,000/sec is 0.3 or greater and 2 or less.

12. The inner liner of claim 1 , wherein a binding reaction occurs at an interface between the layer A and the layer B.

13. A method for producing the inner liner of claim 1 , the method comprising:
extruding, in a multilayer coextrusion process, a resin composition comprising a gas barrier resin, and a resin composition comprising an elastomer, to obtain the inner liner.

Assignees

• Tai Shinji
• Kawai Hiroshi
• Yamakoshi Satoshi
• Isoyama Kouta
• Hikasa Masao
• Takahashi Yuwa
• Kitano Hideki
• Amamoto Tetsuo
• Tanaka Takatsugu
• Kuraray Co
• Bridgestone Corp

Inventors

• Tai Shinji
• Kawai Hiroshi
• Yamakoshi Satoshi
• Isoyama Kouta
• Hikasa Masao
• Takahashi Yuwa
• Kitano Hideki
• Amamoto Tetsuo
• Tanaka Takatsugu

Classifications

• Y10T428/269

  including synthetic resin or polymer layer or component · CPC title

• C09J121/00

  Adhesives based on unspecified rubbers · CPC title

• B32B27/34

  comprising polyamides · CPC title

• B32B27/40

  comprising polyurethanes · CPC title

• B32B27/08 Primary

  of synthetic resin · CPC title