Oriented thermoplastic elastomer film and process for producing the same

a technology of thermoplastic elastomer and oriented thermoplastic, which is applied in the direction of thin material handling, transportation and packaging, etc., can solve the problem that thermoplastic elastomer films do not have the suitable stretching dynamics, and achieve the effect of reducing gas permeability and improving fatigue resistan

Inactive Publication Date: 2006-10-26
EXXONMOBIL CHEM PAT INC +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0004] The objects of the present invention are to provide an oriented thermoplastic elastomer film having a reduced gas permeability and improved fatigue resistance and also to provide a method of preparing the same.
[0005] In accordance with the present invention, there is provided an oriented thermoplastic elastomer film having reduced permeability and improved fatigue resistance comprising a dynamically vulcanized polymer blend of (A) a halogenated isobutylene elastomer and (B) polyamide, the film is produced by casting or blowing the above polymer blend under the condition such that a shear rate at a die lip for casting or blowing is regulated to control the molecular arrangement in the film, whereby the planar birefringence (PBR) of the resultant film becomes greater or equal to 0.002, preferably the PBR is 0.004 or more. DISCLOSURE OF INVENTION
[0007] The present invention relates to an oriented thermoplastic elastomer film having reduced permeability and improved fatigue resistance and to a method of preparing the same.

Problems solved by technology

This thermoplastic elastomer film does not have the suitable stretching dynamics for it to be oriented by a sequential bi-axial orientation process.

Method used

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  • Oriented thermoplastic elastomer film and process for producing the same

Examples

Experimental program
Comparison scheme
Effect test

examples 1-8

[0047] BIMS was pre-compounded with curatives in a Banbury internal mixer and pelletized with the anti-block agent prior to its mixing with Nylon. Mixing and dynamic vulcanization of Nylon and BIMS were done in a twin-screw extruder at about 230° C. These mixes were then cast or blown into films. 2″ diameter disks were punched out from these films and conditioned in a vacuum oven at 60° C. overnight prior to the permeability measurements. Oxygen permeation values of these films at 60° C. were measured using a Mocon OX-TRAN 2 / 61 permeability tester. Principal refractive indices along the three principal directions of these films were determined using a Metricon prism-coupling device. The operation wavelength was 632.8 nm generated by a low-power He-Ne laser. Using the three principal refractive indices, the average refractive index could be calculated as:

n>=(n1+n2+n3) / 3

wherein, is the average refractive index. 1, 2, and 3 refer to machine, transverse, and normal (normal to the fil...

examples 9-13

[0049] In Examples 9 to 13, Nylon 1 matrix was used but without the plasticizer and compatibilizer. 6PPD could be a curative at the mixing temperature of 230° C. by crosslinking BIMS through benzylic bromines and, hence, removing them from reactive compatibilization. DM16D is a viscosity enhancer for BIMS that also react with benzylic bromine of BIMS. This modification of the interfacial bonding with the usage of DM16D and 6PPD could significantly lower the planar orientation and raise the film permeability as shown in Table 2. The results are shown in FIG. 1. Regardless, a good correlation could be found between PBR and permeability. The higher refractive index value in comparison with that in Table 1 reflects the fact that the Nylon matrix has no plasticizer. Hence, higher density or higher refractive index is expected.

TABLE 2Example No.91011*112*113*1Formulation(parts byweight)BIMS100100100100100DM16D001.02.03.06PPD00.6000ZnO0.150.150.150.150.15St-acid0.600.600.600.600.60ZnSt0....

examples 14-19

[0050] In Examples 14-19, Nylon 2 matrix, without N11 and without plasticizer, was used. In blending with Nylon 2, viscosity modifier, such as DM16D and 6PPD, is required to provide good viscosity matching and fine BIMS rubber dispersions. The concentration used for the anti-blocking agents listed in Table 3 is 0.5 to 1 phr. As indicated in Table 3, using ZnO as the anti-blocking agent could significantly affect the orientation. This anti-blocking agent may act as curative and, hence, remove benzylic bromines from BIMS for its reactive compatibilization with Nylon. A large removal of benzylic bromines from BIMS could lower the interfacial bonding between the Nylon and BIMS dispersions and reduce the ability of the film manufacturing process to orient Nylon. However, overall correlation between PBR and permeability holds. The even higher refractive index value as compared with that in Table 2 is the result of the N6 / 66 matrix used. The results are also shown in

TABLE 3Example No.141...

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Abstract

An oriented thermoplastic elastomer film having reduced permeability and improved fatigue resistance comprising a dynamically vulcanized polymer blend of (A) a halogenated isobutylene elastomer and (B) polyamide, the film is produced by C casting or blowing the above polymer blend under the condition such that a shear rate at a die lip for casting or blowing is regulated to control the molecular arrangement in the film, whereby the planar birefringemence (PBR) of the resultant film becomes greater or equal to 0.002 and a production process of the same.

Description

TECHNICAL FIELD [0001] The present invention relates to an oriented thermoplastic elastomer film having reduced permeability and improved fatigue resistance and also to a method of preparing the same. More particularly, the present invention relates to a process for producing a thermoplastic elastomer film composition with enhanced planar orientation for reduction in gas permeability and a process for producing a pneumatic tire using the same. BACKGROUND ART [0002] EP722850B1 disclosed a low-permeability thermoplastic elastomer composition that is superior as a gas-barrier layer in pneumatic tires. This thermoplastic composition comprises a low-permeability thermoplastic matrix such as polyamides or blends of polyamides, in which a low-permeability rubber such as brominated poly(isobutylene-co-p-methylstyrene) (i.e., or BIMS) is dispersed. Subsequently, in both EP857761A1 and EP969039A1, viscosity ratio between the thermoplastic matrix and the rubber dispersion was specified in orde...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): C08L77/00C08L23/28C08L77/02C08L77/06
CPCC08L23/283Y10T428/268C08L77/02C08L77/06C08L77/00Y10T428/26Y10T428/254Y10T428/269C08L2666/20C08L2666/06C08L2666/08C08L2666/04Y10T428/249921
Inventor SOEDA, YOSHIHIROTSOU, HAISHUNG ANDYCARAWAY, FOSHEE JOYCE
Owner EXXONMOBIL CHEM PAT INC
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