Stabilized dynamically vulcanized thermoplastic elastomer compositions useful in fluid barrier applications

Patent metadata

Field	Value
Publication number	US-9540510-B2
Application number	US-200813140080-A
Country	US
Kind code	B2
Filing date	Dec 17, 2008
Priority date	Dec 17, 2008
Publication date	Jan 10, 2017
Grant date	Jan 10, 2017

Abstract

A stabilized, dynamically vulcanized thermoplastic elastomer composition comprising dispersed dynamically vulcanized particles of at least one first elastomer or rubber comprising halogenated isobutylene-containing elastomer and dispersed particles of at least one second elastomer or rubber comprising at least one functional group capable of reacting with and grafting to a polyamide, the particles of the at least one first and at least one second elastomers dispersed in a continuous thermoplastic polyamide or nylon resin matrix comprising at least one nylon homopolymer, nylon copolymer or mixture thereof, the composition or the at least one first elastomer further comprising at least one stabilizer against degradation induced by exposure to actinic, particularly ultraviolet, radiation. The compositions are preferably produced in a mixing extruder and are suitable for producing durable, flexible, thermoplastic elastomer fluid barrier films or layers useful in industrial articles such as vehicle tire innerliners and hoses.

First claim

The invention claimed is:

1. A thermoplastic elastomer composition, said composition comprising a continuous thermoplastic resin selected from the group consisting of nylon 6, nylon 11, nylon 12, nylon 6/12 copolymer, nylon 6/66 copolymer and mixtures thereof, said thermoplastic resin having a Young's modulus of more than 500 MPa and an air permeation coefficient of less than 60×10 −12 cc cm/cm 2 sec cmHg at 30° C., dispersed particles of at least one first elastomer comprising halogenated isobutylene-containing elastomer selected from the group consisting of halogenated butyl rubber and halogenated poly(isobutylene-co-p-methylstyrene) copolymer and dispersed particles of at least one second elastomer having at least one functional group capable of grafting to the continuous thermoplastic resin matrix, said at least one second elastomer selected from the group consisting of maleic anhydride grafted styrene-ethylene/butadiene-styrene rubber, maleated ethylene-propylene copolymer rubber, maleated ethylene-butene rubber, maleated ethylene-hexene rubber, maleated ethylene-octene rubber, maleated ethylene-decene rubber, maleated ethylene-vinyl acetate copolymer, maleated ethylene-methyl acrylate copolymer, maleated ethylene-ethyl acrylate copolymer, and maleated ethylene-acrylic acid copolymer dispersed in the continuous thermoplastic resin, said composition or said at least one first elastomer further comprising at least one stabilizer against degradation induced by exposure to ultraviolet rays, wherein said stabilizer consists of (i) (a) 2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol or (b) 2-(2H-benzotriazol-2-yl)-4,6-ditert-pentylphenol and (ii) 3,5-di-t-butyl-4-hydroxybenzoic acid, hexadecyl ester.

2. The composition according to claim 1 wherein said stabilizer is dispersed in said halogenated elastomer or in said thermoplastic resin prior to said halogenated elastomer being dispersed in the thermoplastic resin by means of being dynamically vulcanized or during dynamic vulcanization of said halogenated elastomer.

3. The composition according to claim 2 wherein said halogenated elastomer further comprises at least one curing agent or a cure system suitable for crosslinking said halogenated elastomer.

4. The composition according to claim 1 wherein said halogenated elastomer is dispersed in said thermoplastic resin matrix in the form of particles having an average size of about 0.1 microns to about 1.0 microns and said second elastomer is dispersed in said thermoplastic resin matrix as particles having an average size of about 0.1 microns to about 1.0 microns.

5. The composition according to claim 1 , wherein said second elastomer is selected from the group consisting of maleated ethylene-butene rubber, maleated ethylene-hexene rubber, maleated ethylene-octene rubber, maleated ethylene-decene rubber and maleated ethylene-ethyl acrylate copolymer and mixtures thereof.

6. The composition according to claim 5 , wherein said second elastomer comprises maleic anhydride present in an amount of at least 0.01 wt % to a maximum amount selected from the group consisting of 50 wt %, 45 wt %, 40 wt %, 35 wt %, 30 wt %, 25 wt %, 20 wt %, 15 wt %, 10 wt %, 9 wt %, 8 wt %, 7 wt %, 6 wt %, 5 wt %, 4 wt %, 3 wt %, and 2 wt % maleic anhydride.

7. The composition according to claim 1 , wherein said second elastomer is present in an amount in a range selected from the group consisting of: 1 to 20 wt %, 0.5 to 20 wt %, 1 to 10 wt %, 5 to 15 wt %, and 7.5 to 12.5 wt %.

8. The composition according to claim 1 wherein said stabilizer is present at a concentration selected from the group consisting of about 0.1 to about 10 phr, about 0.1 to about 8.0 phr, 0.1 to about 7.5 phr, 0.1 to about 5.0 phr, 0.1 to about 3.5 phr, about 0.2 to about 6.5 phr, about 0.25 to about 5.0, about 0.25 to about 3.5 phr, about 0.25 to about 2.0 phr, about 0.25 to about 1.75 phr, and about 0.25 to about 1.5 phr.

9. The composition according to claim 1 further comprising at least one sterically hindered phenolic antioxidant.

10. The composition according to claim 9 wherein said antioxidant is selected from the group consisting of N,N′-hexane-1,6-diylbis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide; pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate); 2,2′-methylenebis(4-ethyl-6-tert-butyl)phenol; and 2,2′-methylenebis(4-methyl-6-tert-butyl)phenol.

11. The composition according to claim 1 wherein said thermoplastic resin is nylon 6/66 copolymer.

12. The composition according to claim 1 wherein said at least one halogenated isobutylene-containing elastomer is halogenated poly(isobutylene-co-p-methyl styrene) copolymer.

13. The composition of claim 1 prepared according to a dynamic vulcanization process conducted in a suitable mixer capable of applying shear to said polymer and elastomer components at elevated temperature, said process comprising the steps of: (1) dispersing in said halogenated elastomer at least one curing agent suitable for crosslinking said halogenated elastomer to provide a pre-compounded halogenated elastomer composition, using shear conditions, mixing time and a temperature sufficient to substantially uniformly disperse said curing agent, but insufficient to cause substantial crosslinking of said halogenated elastomer; (2) introducing said at least one thermoplastic resin into said mixer and applying sufficient shear and heat to cause the thermoplastic resin to melt and flow to form a thermoplastic resin mixture; (3) introducing at least one thermoplastic resin plasticizer in an amount sufficient to cause the viscosity of said thermoplastic resin mixture to substantially match the viscosity of said pre-compounded halogenated elastomer at the temperature and under the shear conditions present in said mixer; (4) introducing said pre-compounded halogenated elastomer into said mixer and applying heat and shear in sufficient quantity to initiate dynamic vulcanization of said halogenated elastomer; (5) introducing said second elastomer and continuing the heating and shearing to substantially disperse said second elastomer and substantially complete said dynamic vulcanization of said halogenated elastomer; and (6) delivering said dynamically vulcanized thermoplastic elastomer composition from said mixer; wherein at least one stabilizer is added to either the halogenated elastomer or the thermoplastic resin homopolymer or copolymer in step (1) or step (2).

14. The composition according to claim 13 wherein said halogenated elastomer is dispersed in said continuous thermoplastic resin matrix in the form of particles having an average size of about 0.1 microns to about 1.0 microns and said second elastomer is dispersed in said continuous thermoplastic resin matrix as particles having an average size of about 0.1 microns to about 1.0 microns.

15. The composition according to claim 13 , wherein said second elastomer is selected from the group consisting of maleated ethylene-butene rubber, maleated ethylene-hexene rubber, maleated ethylene-octene rubber, maleated ethylene-decene rubber and maleated ethylene-ethyl acrylate copolymer and mixtures thereof.

16. The composition according to claim 14 wherein said polyamide is selected from the group consisting of nylon 6, nylon 11, nylon 6/66 copolymer and mixtures thereof; and said at least one halogenated isobutylene-containing elastomer is brominated poly(isobutylene-co-p-methylstyrene) copolymer.

Assignees

• Blok Edward John
• Harrington Bruce Alan
• Hara Yuichi
• Tomoi Shusaku
• Yokohama Rubber Co Ltd
• Exxonmobil Chemical Patents Inc

Inventors

• Blok Edward John
• Harrington Bruce Alan
• Hara Yuichi
• Tomoi Shusaku

Classifications

• C08L55/02

  ABS [Acrylonitrile-Butadiene-Styrene] polymers · CPC title

• C08L53/02

  of vinyl-aromatic monomers and conjugated dienes · CPC title

• C08L51/08

  grafted on to macromolecular compounds obtained otherwise than by reactions only involving unsaturated carbon-to-carbon bonds · CPC title

• C08L51/06

  grafted on to homopolymers or copolymers of aliphatic hydrocarbons containing only one carbon-to-carbon double bond · CPC title

• C08L51/04

  grafted on to rubbers · CPC title