Multi-Layer Golf Balls Comprising Ionomers with a Percent Neutralization Gradient

1 . A multilayer golf ball comprising a core, an intermediate layer, and a cover, the intermediate layer and cover bring adjacent to each other, wherein

at least one of the intermediate layer or cover comprises a first highly neutralized moisture resistant acid polymer composition having a moisture vapor transmission rate of 8 g-mil/100in2/day or less;

the adjacent intermediate layer or cover comprises a second highly neutralized acid polymer; and

the two adjacent layers, in tandem, form a percent neutralization gradient.

2 . The golf ball of claim 1 , wherein the percent neutralization gradient progressively increases toward the outside of the golf ball.

3 . The golf ball of claim l, wherein the percent neutralization gradient progressively decreases toward the outside of the golf ball.

4 . The golf ball of claim 1 , wherein the first highly neutralized moisture resistant acid polymer has a moisture vapor transmission rate of 5 g-mil/100 in 2 /day or less.

5 . The golf ball of claim 4 , wherein the first highly neutralized moisture resistant acid polymer has a moisture vapor transmission rate of 3 g-mil/100 in 2 /day or less.

6 . The golf ball of claim 1 , wherein at least one of the first and second highly neutralized acid polymers comprise acid groups that are at least 90% neutralized.

7 . The golf ball of claim 6 , wherein at least one of the first and second highly neutralized acid polymers comprises acid groups that are 100% neutralized.

8 . The golf ball of claim 1 , wherein the first highly neutralized moisture resistant acid polymer is neutralized with less hydrophilic cation sources selected from the group consisting of metal ions and compounds of potassium, cesium, calcium, barium, manganese, copper, zinc, and tin.

9 . The golf ball of claim 1 , wherein the golf ball has a first volume and the layers formed from the first and second highly neutralized acid polymers combine to have a second volume that is at least 40 percent of the first volume.

10 . The golf ball of claim 9 , wherein the second volume is at least 70 percent of the first volume.

11 . The golf ball of claim 10 , wherein the second volume is at least 90 percent of the first volume.

12 . A multi-layer golf ball comprising a core and at least three adjacent layers comprising highly-neutralized acid polymers, the three adjacent layers comprising an innermost layer, an intermediate layer, and an outermost layer, wherein the golf ball has a first volume and a combination of the innermost, intermediate, and outermost adjacent layers form a percent neutralization gradient and have a second volume that is at least about 40% of the first volume.

13 . The golf ball of claim 12 , wherein the percent neutralization gradient progressively increases toward the outside of the golf ball.

14 . The golf ball of claim 12 , wherein the percent neutralization of the innermost layer is from about 20 to 70, the percent neutralization of the intermediate layer is from about 50 to 90, and the percent neutralization of the outermost layer is from about 70 to 100, and wherein the percent neutralization of the innermost layer is less than the percent neutralization of the intermediate layer, and the percent neutralization of the intermediate layer is less than the percent neutralization of the outermost layer.

15 . The golf ball of claim 12 , wherein the percent neutralization gradient progressively decreases toward the outside of the golf ball.

16 . The golf ball of claim 12 , wherein the percent neutralization of the innermost layer is from about 70 to 100, the percent neutralization of the intermediate layer is from about 50 to 90, and the percent neutralization of the outermost layer is from about 20 to 70, and wherein the percent neutralization of the innermost layer is greater than the percent neutralization of the intermediate layer, and the percent neutralization of the intermediate layer is greater than the percent neutralization of the outermost layer.

17 . The golf ball of claim 12 , wherein the second volume is at least 70% of the first volume.

18 . The golf ball of claim 17 , wherein the second volume is at least 90% of the first volume.

19 . A multi-layer golf ball comprising a core layer, an intermediate layer adjacent to the core layer, and an outermost layer adjacent to the intermediate layer, wherein the golf ball has a first volume and at least two of the adjacent layers comprise a neutralized acid polymer, said two adjacent layers combining to form a percent neutralization gradient.

20 . The golf ball of claim 19 , wherein the combined adjacent layers have a second volume that is at least 40% of the first volume.

21 . The golf ball of claim 20 , wherein the second volume is at least 70% of the first volume.

22 . The golf ball of claim 21 , wherein the second volume is at least 90% of the first volume.

23 . The golf ball of claim 19 , wherein the percent neutralization gradient progressively increases toward the outside of the golf ball.

24 . The golf ball of claim 19 , wherein the percent neutralization gradient progressively decreases toward the outside of the golf ball.

25 . The golf ball of claim 19 , wherein the neutralized acid polymer comprises acid groups that are neutralized from about 80 to 100%.