Thermoplastic method, composition, and article

1. A method of preparing a thermoplastic composition, comprising:

melt kneading a thermoplastic vulcanizate and a first hydrogenated block copolymer of an alkenyl aromatic compound and a conjugated diene to form a vulcanizate-copolymer blend; and

melt kneading the vulcanizate-copolymer blend, a poly(arylene ether), and a second hydrogenated block copolymer of an alkenyl aromatic compound and a conjugated diene;

wherein the thermoplastic vulcanizate comprises a crystalline or semi-crystalline thermoplastic polyolefin; and a dynamically partially vulcanized rubber selected from ethylene-propylene copolymers, ethylene-propylene-diene terpolymers, styrene butadiene rubber, nitrile butadiene rubber, isobutene-isoprene rubber, styrene-(ethylene-styrene)-butadiene block copolymers, butyl rubber, isobutylene-p-methylstyrene copolymers, brominated isobutylene-p-methylstyrene copolymers, natural rubber, and combinations thereof;

wherein the first hydrogenated block copolymer and the second hydrogenated block copolymer are each independently a styrene-(ethylene-butylene)-styrene triblock copolymer;

wherein the poly(arylene ether) comprises 2,6-dimethyl-1,4-phenylene ether units;

wherein the vulcanizate-copolymer blend comprises a dispersed phase having a mean particle size, measured along a major axis, of about 0.1 to about 3 micrometers; and

wherein the thermoplastic composition comprises a dispersed phase having a mean particle size, measured along a major axis, of about 1 to about 3 micrometers.

2. A method of preparing a thermoplastic composition, comprising:

melt kneading a thermoplastic vulcanizate and a first hydrogenated block copolymer of an alkenyl aromatic compound and a conjugated diene in a weight ratio of about 70:30 to about 98:2 to form a vulcanizate-copolymer blend; and

melt kneading about 10 to about 50 weight percent of the vulcanizate-copolymer blend, about 10 to about 50 weight percent of a poly(arylene ether), and about 5 to about 30 weight percent of a second hydrogenated block copolymer of an alkenyl aromatic compound and a conjugated diene;

wherein the thermoplastic vulcanizate comprises an ethylene-propylene-ethylidene norbornene terpolymer vulcanizate in a polypropylene matrix;

wherein the first hydrogenated block copolymer and the second hydrogenated block copolymer are each independently a styrene-(ethylene-butylene)-styrene triblock copolymer;

wherein the poly(arylene ether) comprises 2,6-dimethyl-1,4-phenylene ether units;

wherein the vulcanizate-copolymer blend comprises a dispersed phase having a mean particle size, measured along a major axis, of about 0.1 to about 3 micrometers;

wherein the thermoplastic composition comprises a dispersed phase having a mean particle size, measured along a major axis, of about 1 to about 3 micrometers; and

wherein all weight percents are based on the total weight of the composition.

3. The method of claim 2 , further comprising melt kneading about 5 to about 30 weight percent of a hydrocarbon resin with the vulcanizate-copolymer blend, the poly(arylene ether), and the second hydrogenated block copolymer; wherein the hydrocarbon resin is a hydrogenated aromatic hydrocarbon resin.

4. A thermoplastic composition prepared according to the method of claim 1 .

5. A thermoplastic composition prepared according to the method of claim 2 .

6. The composition of claim 5 , exhibiting a UL 94 rating of V-0 at a thickness of 3.2 millimeters.

7. The composition of claim 5 , exhibiting a tensile strength of about 13 to about 16 megaPascals at 25° C., measured according to ASTM D638.

8. The composition of claim 5 , exhibiting a tensile elongation at break of about 170 to about 230 percent at 25° C., measured according to ASTM D638.

9. A thermoplastic composition, comprising a blended mixture of:

(a) about 5 to about 60 weight percent of a vulcanizate-copolymer blend of (a1) a thermoplastic vulcanizate and (a2) a hydrogenated block copolymer of an alkenyl aromatic compound and a conjugated diene; wherein the thermoplastic vulcanizate comprises an ethylene-propylene-ethylidene norbornene terpolymer vulcanizate in a polypropylene matrix; and wherein the hydrogenated block copolymer comprises a styrene-(ethylene-butylene)-styrene triblock copolymer; and wherein the vulcanizate-copolymer blend comprises a dispersed phase having a mean particle size, measured along a major axis, of about 0.5 to about 2.0 micrometers;

(b) about 10 to about 60 weight percent of a poly(arylene ether); wherein the poly(arylene ether) comprises a plurality of structural units of the formula

wherein for each structural unit, each Q 1 is methyl and each Q 2 is independently hydrogen or methyl;

(c) a hydrogenated block copolymer of an alkenyl aromatic compound and a conjugated diene; wherein the hydrogenated block copolymer comprises a styrene-(ethylene-butylene)-styrene triblock copolymer that was not part of the vulcanizate-copolymer blend; and

(d) and about 2 to about 40 weight percent of a hydrocarbon resin; wherein the hydrocarbon resin is a hydrogenated aromatic hydrocarbon resin;

wherein the total amount of the first hydrogenated block copolymer and the second hydrogenated block copolymer is about 2 to about 40 weight percent;

wherein all weight percents are based on the total weight of the composition; and

wherein the composition comprises a dispersed phase having a mean particle size, measured along a major axis, of about 1 to about 3 micrometers.

10. An article comprising the composition of claim 4 .

11. An article comprising the composition of claim 5 .

12. An article comprising the composition of claim 9 .

13. A thermoplastic composition, comprising a blended mixture of:

(a) about 5 to about 60 weight percent of a vulcanizate-copolymer blend of (a1) a thermoplastic vulcanizate and (a2) a hydrogenated block copolymer of an alkenyl aromatic compound and a conjugated diene; wherein the thermoplastic vulcanizate comprises an ethylene-propylene-ethylidene norbornene terpolymer vulcanizate in a polypropylene matrix; and wherein the hydrogenated block copolymer comprises a styrene-(ethylene-butylene)-styrene triblock copolymer; and wherein the vulcanizate-copolymer blend comprises a dispersed phase having a mean particle size, measured along a major axis, of about 0.5 to about 2.0 micrometers;

(b) about 10 to about 60 weight percent of a poly(arylene ether); wherein the poly(arylene ether) comprises a plurality of structural units of the formula

wherein for each structural unit, each Q 1 is methyl and each Q 2 is independently hydrogen or methyl;

(c) a hydrogenated block copolymer of an alkenyl aromatic compound and a conjugated diene; wherein the hydrogenated block copolymer comprises a styrene-(ethylene-butylene)-styrene triblock copolymer that was not part of the vulcanizate-copolymer blend; and

(d) and about 2 to about 40 weight percent of a hydrocarbon resin; wherein the hydrocarbon resin is a hydrogenated aromatic hydrocarbon resin;

wherein the total amount of the first hydrogenated block copolymer and the second hydrogenated block copolymer is about 2 to about 40 weight percent;

wherein all weight percents are based on the total weight of the composition; and

wherein the composition comprises a dispersed phase having a mean particle size, measured along a major axis, of about 1 to about 3 micrometers;

wherein the composition exhibits one or more of the following properties: a UL 94 rating of V-0 at a thickness of 3.2 millimeters; a tensile strength of about 13 to about 16 megaPascals at 25° C., measured according to ASTM D 638;and a tensile elongation at break of about 170 to about 230 percent at 25° C., measured according to ASTM D 638.