Film for tire inner liner, and method for manufacturing the same

Patent metadata

Field	Value
Publication number	US-9757984-B2
Application number	US-201113977317-A
Country	US
Kind code	B2
Filing date	Dec 30, 2011
Priority date	Dec 30, 2010
Publication date	Sep 12, 2017
Grant date	Sep 12, 2017

Abstract

The present invention relates to a film for a tire inner liner including a base film layer including a copolymer or a mixture of a polyamide-based resin and a polyether-based resin, and an adhesive layer including a resorcinol-formalin-latex (RFL)-based adhesive, and having low shrinkage rate when elongated at a high temperature and then cooled to room temperature, and a method for manufacturing the same.

First claim

What is claimed is:

1. A film for a tire inner liner, comprising:
a base film layer comprising a polyamide-based resin and an elastomer copolymer comprising polyamide-based segments and polyether-based segments; and
an adhesive layer comprising a resorcinol-formalin-latex (RFL)-based adhesive,
wherein the content of the polyether-based segments in the elastomer copolymer is 15 to 50 wt % based on total weight of the base film layer, and the base film layer comprises the polyamide-based resin and the elastomer copolymer in a weight ratio of 5:5 to 4:6,
the thickness of the base film layer is 30 to 300 μm, and
the film for a tire inner liner has a shrinkage rate of 5% or less when elongated 50 to 150% at 80 to 160° C. and then cooled to room temperature,
wherein the elastomer copolymer has a weight average molecular weight of 50,000 to 300,000.

2. The film for a tire inner liner according to claim 1 , wherein the film for a tire inner liner has a shrinkage rate of 3% or less when elongated 150% at 160° C. and then cooled to room temperature.

3. The film for a tire inner liner according to claim 1 , wherein the film for a tire inner liner has a coefficient of thermal expansion of 100×10 −6 /° C. to 500×10 −6 /° C. at 80 to 160° C.

4. The film for a tire inner liner according to claim 1 , wherein the film for a tire inner liner has tensile stress of 310 kg/cm 2 or less when elongated 150% at 160° C.

5. The film for a tire inner liner according to claim 1 , wherein the polyamide-based resin has relative viscosity (sulfuric acid 96% solution) of 3.0 to 3.5.

6. The film for a tire inner liner according to claim 1 , wherein the elastomer copolymer comprises polyamide-based segments and polyether-based segments in a weight ratio of 6:4 to 3:7.

7. The film for a tire inner liner according to claim 1 , wherein the base film layer is an unstretched film.

8. The film for a tire inner liner according to claim 1 , wherein the adhesive layer is formed on at least one side of the base film layer to a thickness of 0.1 to 20 μm.

9. The film for a tire inner liner according to claim 1 , wherein the resorcinol-formalin-latex (RFL)-based adhesive comprises 2 to 30 wt % of a condensate of resorcinol and formaldehyde, and 70 to 98 wt % of latex.

10. The film for a tire inner liner according to claim 1 , wherein the base film layer has an equilibrium moisture content (25° C., 65% RH) of 5 to 9%.

11. A method for manufacturing a film for a tire inner liner, comprising:
mixing at a weight ratio of 5:5 to 4:6 a polyamide-based resin and an elastomer copolymer comprising polyamide-based segments and polyether-based segments;
melting and extruding the mixture of the polyamide-based resin and the elastomer copolymer comprising polyamide-based segments and polyether-based segments at 230 to 300° C. to form a base film layer having a thickness of 30 to 300 μm; and
forming an adhesive layer comprising a resorcinol-formalin-latex (RFL)-based adhesive on at least one side of the base film layer,
wherein the content of the polyether-based segments in the elastomer copolymer is 15 to 50 wt % based on total weight of the base film layer, and
the film for a tire inner liner has a shrinkage rate of 5% or less when elongated 50 to 150% at 80 to 160° C. and then cooled to room temperature,
wherein the elastomer copolymer has a weight average molecular weight of 50,000 to 300,000.

12. The method according to claim 11 , wherein the manufactured tire inner liner has a coefficient of thermal expansion of 1×10 −6 /° C. to 5000×10 −6 /° C. at 80 to 160° C.

13. The method according to claim 11 , wherein the elastomer copolymer comprises polyamide-based segments and polyether-based segments in a weight ratio of 6:4 to 3:7.

14. The method according to claim 11 , further comprising a step of solidifying the base film layer formed by melting and extrusion in a cooling part maintained at 5 to 40° C.

15. The method according to claim 11 , wherein the step of forming an adhesive layer comprises coating an adhesive comprising 2 to 30 wt % of a condensate of resorcinol and formaldehyde, and 68 to 98 wt % of latex, on at least one side of the base film layer to a thickness of 0.1 to 20 μm.

16. The method according to claim 11 , further comprising a step of aging the base film layer under constant temperature and humidity conditions.

17. The method according to claim 16 , wherein the step of aging the base film layer under constant temperature and humidity conditions is conducted at a temperature selected from 20° C. to 30° C. and relative humidity selected from 60% to 70% for 12 hours to 48 hours.

Assignees

• Kwon So-Yeon
• Jeong Young-Han
• Chung Il
• Jeon Ok-Hwa
• Kolon Inc

Inventors

• Kwon So-Yeon
• Jeong Young-Han
• Chung Il
• Jeon Ok-Hwa

Classifications

• C08L77/00

  Compositions of polyamides obtained by reactions forming a carboxylic amide link in the main chain (of polyhydrazides C08L79/06; of polyamideimides or polyamide acids C08L79/08); Compositions of derivatives of such polymers · CPC title

• C09J7/0282

  Chemistry & Metallurgy · mapped topic

• C09D171/02

  Polyalkylene oxides · CPC title

• Y10T428/31761

  Next to aldehyde or ketone condensation product · CPC title

• B32B27/42

  comprising condensation resins of aldehydes, e.g. with phenols, ureas or melamines · CPC title