Thermoplastic elastomer composition and process for production thereof and low permeability hose using the same

• US 5,910,544 A
• Filed: 06/25/1997
• Issued: 06/08/1999
• Est. Priority Date: 11/02/1995
• Status: Expired due to Term

• Current Assignee: Yokohama Rubber Company Limited
• Original Assignee: Yokohama Rubber Company Limited
• Inventors: Kuroda, Noriaki, Aoyagi, Yoshihiro, Kawaguchi, Gou, Watanabe, Jiro, Kawazura, Tetsuji, Ozawa, Osamu
• Primary Examiner(s): Mosley, Terressa
• Application Number:
  US08/860,251
• Time in Patent Office: 713 Days
• Field of Search: 525/178, 525/179
• US Class Current: 525/178
• CPC Class Codes: B60C 1/00 Tyres characterised by the chemical composition or the physical arrangement or mixture of the composition
• CPC Class Codes: B60C 1/0008 Compositions of the inner liner
• CPC Class Codes: B60C 11/1346 covered by a rubber different from the tread rubber
• CPC Class Codes: B60C 13/001 Decorating, marking or the like
• CPC Class Codes: C08L 101/00 Compositions of unspecified macromolecular compounds
• CPC Class Codes: C08L 23/16 Elastomeric ethene-propene or ethene-propene-diene copolymers, e.g. EPR and EPDM rubbers
• CPC Class Codes: C08L 23/22 Copolymers of isobutene; Butyl rubber ; Homo- or copolymers of other iso-olefins
• CPC Class Codes: C08L 23/28 by reaction with halogens or compounds containing halogen C08L23/32 takes precedence
• CPC Class Codes: C08L 23/283 Halogenated homo- or copolymers of iso-olefins
• CPC Class Codes: C08L 2666/04 Macromolecular compounds according to groups C08L7/00 - C08L49/00, or C08L55/00 - C08L57/00; Derivatives thereof
• CPC Class Codes: C08L 2666/14 Macromolecular compounds according to C08L59/00 - C08L87/00; Derivatives thereof
• CPC Class Codes: C08L 2666/20 Macromolecular compounds having nitrogen in the main chain according to C08L75/00 - C08L79/00; Derivatives thereof
• CPC Class Codes: C08L 2666/24 Graft or block copolymers according to groups C08L51/00, C08L53/00 or C08L55/02; Derivatives thereof
• CPC Class Codes: C08L 53/00 Compositions of block copolymers containing at least one sequence of a polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers
• CPC Class Codes: C08L 77/00 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

Abstract

A thermoplastic elastomer composition comprising:

i) from 15 to 80 parts by weight of a polyamide thermoplastic resin as component A;

ii) from 20 to 85 parts by weight of a rubber composition as component B, the rubber composition containing a copolymer rubber composed of a copolymer of a C₄ to C₇ isomonoolefin and a p-alkylstyrene, where at least a part of the p-alkylstyrene unit portions thereof have a halogen atom; and

iii) a cross-linking agent,

wherein the thermoplastic resin component A forms a continuous phase and at least part of component B is dispersed in component A as a dispersed phase and at least part of the dispersed phase is cross-linked by the cross-linking agent.

Claims

1. A thermoplastic elastomer composition comprising:

i) from 15 to 80 parts by weight of a polyamide thermoplastic resin as component A;

ii) from 20 to 85 parts by weight of a rubber composition as component B, said rubber composition containing a copolymer rubber composed of a copolymer of a C₄ to C₇ isomonoolefin and a p-alkylstyrene, where at least a part of the p-alkylstyrene unit portions thereof have a halogen atom; and

iii) a cross-linking agent,

wherein component A forms a continuous phase and at least part of component B is dispersed in component A as a dispersed phase and at least part of the dispersed phase is cross-linked by the cross-linking agent.

2. A process for producing the thermoplastic elastomer composition of claim 1 comprising:

mixing component A with component B at least at the melting temperature of component A, then

adding the cross-linking agent during the mixing to cross-link component B.

3. A hose comprising an inner tube, a reinforcing layer, and an outer cover, wherein at least part of the inner tube and/or part of the outer cover is formed from the thermoplastic elastomer composition of claim 1.

4. The thermoplastic elastomer composition of claim 1, wherein component B has a p-alkylstyrene content of 5.5 to 25% by weight, a halogen content of at least 1.0% by weight, and a Mooney viscosity ML₁₊₈ (125°

C.) of at least 30 and component A has a gas permeation coefficient of not more than 2 mg·

mm/24 hr·

cm².

5. A low permeability hose comprising an inner tube, a reinforcing layer, and an outer cover wherein at least one of the inner tube and outer cover of the hose is formed from the thermoplastic elastomer composition of claim 4.

6. A thermoplastic elastomer composition of claim 1, wherein component A has an air permeation coefficient of not more than 25×

10^-12 cc·

cm/cm² ·

sec·

cmHg and component B has an air permeation coefficient of not more than 1.0×

10^-10 cc·

cm/cm² sec·

cmHg, and wherein component A has a melt viscosity (η

_m), and component B has a melt viscosity (η

_d), and the difference in solubility parameters of component A and component B at a kneading temperature satisfy the following relationship (1);

##EQU6## where Δ

SP is the difference in solubility parameters of component B and component A;

Φ

_m is the volume fraction of component A; and

a=-0.0518, and b=0.90.

7. The thermoplastic elastomer composition of claim 1, wherein component A has a gas permeation coefficient of not more than 5.0 mg·

mm/24 hr·

cm² and component B has a gas permeation coefficient of not more than 30.0 mg·

mm/24 hr·

cm², and wherein component A has a melt viscosity (η

_m), and component B has a melt viscosity (η

_d), and the difference in solubility parameters of component A and component B at a kneading temperature satisfy the following relationship (1);

##EQU7## where Δ

SP is the difference in solubility parameters of component B and component A;

Φ

_m is the volume fraction of component A; and

a=-0.0518, and b=0.90.

8. A hose containing the thermoplastic elastomer composition of claim 7 as a gas barrier layer.

9. A low permeability thermoplastic elastomer composition comprising the thermoplastic elastomer composition of claim 1 and a barrier thermoplastic resin composition, the thermoplastic elastomer composition having a phase structure wherein the barrier thermoplastic resin composition is dispersed in the form of a layer in the thermoplastic elastomer composition.

10. The low permeability thermoplastic elastomer composition of claim 9, wherein the thermoplastic resin component A forming the continuous phase has an air permeation coefficient of at least 5 cm³ ·

cm/cm² ·

sec·

cmHg or a HFC134a freon gas permeation coefficient of at least 5 mg·

mm/24 hr·

cm² and the barrier thermoplastic resin composition has an air permeation coefficient of not more than 5 cm³ ·

cm/cm² ·

sec·

cmHg or a HFC134a freon gas permeation coefficient of not more than 5 mg·

mm/24hr·

cm².

11. The low permeability thermoplastic elastomer composition of claim 9 or 10 wherein the volume fraction and the melt viscosity of the thermoplastic elastomer composition comprising component A as the continuous phase and component B as the dispersed phase, and the barrier thermoplastic resin composition satisfy the following formula (2) and formula (3):

##EQU8## where, Φ

_d is the volume fraction of the barrier thermoplastic resin composition;

η

_d is the melt viscosity of the barrier thermoplastic resin composition;

Φ

_m is the volume fraction of the thermoplastic elastomer composition comprising component A as the continuous phase and component B as the dispersed phase; and

η

_m is the melt viscosity of the thermoplastic elastomer composition comprising component A as the continuous phase and the rubber component B as the dispersed phase.

12. The low permeability thermoplastic elastomer composition of claim 9 or 10, wherein the barrier thermoplastic resin composition is at least one thermoplastic resin selected from the group consisting of polyamide thermoplastic resins, polyester thermoplastic resins, vinyl thermoplastic resins, and polyvinylidene chloride thermoplastic resins.

13. The low permeability thermoplastic elastomer composition of claim 9 or 10, wherein the layer of the barrier thermoplastic resin composition has a flatness, which is an aspect ratio A in the range of 10 to 500, where A=a/b and a is the length of the long axis and b is the length of the short axis of the layer.

14. A process for producing the low permeability thermoplastic elastomer composition of claim 9 comprising the steps of:

preparing the thermoplastic elastomer composition of the component A and component B and then

mixing the barrier thermoplastic resin composition with the thermoplastic elastomer composition as a second step.

15. A low permeability hose comprising an inner tube and an outer cover, wherein at least one of the inner tube and outer cover is formed from the composition of claim 9 or 10.

16. A functional thermoplastic elastomer composition comprising:

the thermoplastic elastomer composition of claim 1 as component I, and

an insoluble functional thermoplastic resin as component II blended into component I,

said component II having a difference in solubility parameter (SP value) based upon component I of more than 1.0, where the following formula (4) is satisfied;

##EQU9## where, Φ

_A is the volume fraction of component I;

Φ

_B is the volume fraction of component II;

η

_A is the melt viscosity of component I;

η

_B is the melt viscosity of component II; and

the volume fraction of component II based on the total of components I and II is from 1 to 40%.

17. The functional thermoplastic elastomer composition of claim 16, where a solubilizing component III is further included in an amount of from 0.5 to 10% by weight based upon the total weight of component I and component II.

18. The functional thermoplastic elastomer composition of claim 16 or 17, wherein the insoluble functional thermoplastic resin component II is an adhesive thermoplastic resin.

19. A hose comprising an inner tube having an inner and an outer layer, an outer cover and a reinforcing layer adjoining the outer cover, where at least one member of the outer cover of the hose, the inner layer of the inner tube, the outer layer of the inner tube, and the reinforcing layer is formed from the composition of claim 18.

20. A process for producing the functional thermoplastic elastomer composition of claim 16 comprising the steps of:

preparing the thermoplastic elastomer composition as component I, then mixing in the insoluble functional thermoplastic resin component II, and then processing the resultant mixture into a sheet or tube while applying shear stress so as to make the insoluble functional thermoplastic resin component II be positioned at a surface portion thereof.