Compositions of organic acid modified ionomers filled with silica

1. A filled thermoplastic composition comprising an organic acid-modified ionomer and a silica filler wherein

the organic acid-modified ionomer comprises or is produced from an ethylene acid copolymer and an organic acid or salt thereof;

the ethylene acid copolymer comprises copolymerized units of ethylene, copolymerized units of a C 3-8 α,β-ethylenically unsaturated carboxylic acid, and optionally copolymerized units of a softening comonomer selected from the group consisting of vinyl acetate, alkyl acrylate and alkyl methacrylate;

the organic acid comprises at least one aliphatic, monofunctional organic acid having 4 to 36 carbon atoms;

the combined acid moieties in the acid copolymer and the organic acid are nominally neutralized to a level from about 70% to about 100%; and

the silica filler has an oil absorption greater than 250 g oil/100 g silica, as determined according to ASTM D1483-95.

2. The composition of claim 1 wherein the carboxylic acid is acrylic acid or methacrylic acid and the softening comonomer is alkyl acrylate and is present in an amount from 3 to 45% of the acid copolymer.

3. The composition of claim 2 wherein the carboxylic acid is present in an amount from 5 to 20% of the copolymer and softening comonomer is present in an amount from 10 to 45% of the acid copolymer.

4. The composition of claim 3 wherein the silica filler consists essentially of fumed silica, precipitated silica or silica gel.

5. The composition of claim 1 wherein the acid copolymer is a dipolymer of ethylene and acrylic acid or methacrylic acid.

6. The composition of claim 1 wherein the organic acid or salt thereof is present in about 5 to about 60% of the organic acid-modified ionomer.

7. The composition of claim 1 wherein the silica filler consists essentially of fumed silica or precipitated silica.

8. The composition of claim 7 wherein the silica filler is present in the composition in an amount from about 1 to about 20%, based on the weight the composition.

9. The composition of claim 8 wherein the silica filler is present in the composition in an amount from about 3 to about 17%, based on the total weight of the composition.

10. The composition of claim 1 wherein the overall salt of the composition comprises at least about 75 equivalent % magnesium cations or calcium cations.

11. An article comprising or produced from the filled thermoplastic composition of claim 1 .

12. The composition of claim 1 wherein the silica filler has a surface area greater than 100 m 2 /g, measured according to ASTM D1993-03.

13. The article of claim 11 that is a multilayer structure wherein the filled thermoplastic composition is a layer of the multilayer structure.

14. The article of claim 11 wherein the article is film, sheet, sphere, or molded article.

15. The article of claim 11 wherein the article is a golf ball comprising a core and a cover and at least one intermediate layer positioned between the core and the cover, wherein the intermediate layer comprises the filled thermoplastic composition.

16. The article of claim 15 wherein the cover comprises a polyurethane composition, a polyurea composition, or an ionomer composition other than the filled thermoplastic composition.

17. The article of claim 15 wherein the cover comprises the filled thermoplastic composition.

18. The article of claim 15 wherein the core comprises polybutadiene rubber.

19. The article of claim 15 wherein the core comprises an organic acid-modified ionomer composition other than the filled thermoplastic composition.

20. The article of claim 11 wherein the article is a component of a golf club or a footwear structural component; the component of a golf club is a golf club face plate or insert, molded golf club head, club head coated with the composition, and a golf club head filled with the composition; and the footwear structural component is a heel counter, toe puff, sole, or cleat.