Multilayer golf ball containing at least three core layers, at least one intermediate barrier layer, and at least one cover layer

1. A multilayer golf ball comprising:

a core comprising at least three core layers comprising a center, an inner core layer, and an outer core layer;

at least one cover layer; and

at least one moisture vapor barrier layer comprising a locally curable material selected from the group comprising butyl rubber, polysulfide rubber, a single-pack castable polymer comprising uretdione, a single-pack castable polymer comprising isocyanate and an amine, and a single-pack castable polymer comprising isocyanate and a polyol intermediate between the outer core layer and the at least one cover layer and exhibiting a moisture vapor transmission rate less than that of the cover layer;

wherein the center, the inner core layer, and the outer core layer exhibit a hardness gradient,

wherein the hardness gradient increases toward the at least one intermediate vapor barrier layer, and wherein:

the center hardness is no more than about 50 Shore C;

the inner core hardness is greater than about 50 Shore C;

the outer core hardness is greater than about 65 Shore C; or

a combination thereof.

2. The multilayer golf ball of claim 1 , wherein the thickness of the at least one vapor barrier layer is relatively uniform and is not more than about 0.020 inch.

3. The multilayer golf ball of claim 1 , wherein the at least one vapor barrier layer comprises a thermoplastic elastomeric binder and a particulate material that has a low moisture vapor transmission rate.

4. The multilayer golf ball of claim 1 , comprising a moment of inertia of less than about 85 kg·m 2 .

5. The multilayer golf ball of claim 1 , comprising a coefficient of restitution of greater than about 0.7.

6. The multilayer golf ball of claim 1 , comprising an atti compression of at least about 40.

7. A multilayer golf ball comprising:

a core comprising at least three core layers comprising a center, an inner core layer, and an outer core layer;

at least one cover layer; and

at least one moisture vapor barrier layer comprising a locally curable material selected from the group comprising butyl rubber, polysulfide rubber, single-pack castable polymers comprising uretdione, single-pack castable polymers comprising isocyanate and an amine, and single-pack castable polymers comprising isocyanate and a polyol intermediate between the outer core layer and the at least one cover layer and exhibiting a moisture vapor transmission rate less than that of the cover layer wherein the center, the inner core layer, and the outer core layer exhibit a hardness gradient, wherein:

the center has

a diameter from about 0.5 inch to about 1.6 inches,

a Mooney viscosity greater than about 35,

a deflection under a load of about 100 kg of at least about 1 mm,

a zinc diacrylate content from about 10 to about 40 parts per hundred parts of rubber,

or some combination thereof;

the inner core layer has an outer diameter of not more than about 1.610 inches,

a Mooney viscosity greater than about 35,

a zinc diacrylate content from about 15 to about 45 parts per hundred parts of rubber, or

some combination thereof; and

the outer core layer has

an outer diameter of not more than about 1.660 inches,

a Mooney viscosity greater than about 35,

a zinc diacrylate content from about 15 to about 45 parts per hundred parts of rubber, or

some combination thereof.

8. A multilayer golf ball comprising:

a core comprising at least three core layers comprising a center, an inner core layer, and an outer core layer;

at least one cover layer; and

at least one moisture vapor barrier layer comprising a locally curable material selected from the group comprising butyl rubber, polysulfide rubber, single-pack castable polymers comprising uretdione, single-pack castable polymers comprising isocyanate and an amine, and single-pack castable polymers comprising isocyanate and a polyol intermediate between the outer core layer and the at least one cover layer and exhibiting a moisture vapor transmission rate less than that of the cover layer,

wherein the center, the inner core layer, and the outer core layer exhibit a hardness gradient,

wherein the at least one vapor barrier layer comprises a thermoplastic elastomeric binder and a particulate material that has a low moisture vapor transmission rate,

wherein the thermoplastic elastomeric binder comprises a styrene-diene block copolymer or a styrene-hydrogenated diene block copolymer.

9. A multilayer golf ball comprising:

at least three core layers comprising a center, an inner core layer, and an outer core layer;

at least one cover layer; and

at least one vapor barrier layer comprising a locally curable material selected from the group comprising butyl rubber, polysulfide rubber, single-pack castable polymers comprising uretdione, single-pack castable polymers comprising isocyanate and an amine, and single-pack castable polymers comprising isocyanate and a polyol intermediate between the outer core layer and the at least one cover layer and exhibiting a moisture vapor transmission rate less than that of the cover layer,

wherein the center, the inner core layer, and the outer core layer exhibit a hardness gradient,

wherein the at least one vapor barrier layer comprises a thermoplastic elastomeric binder and a particulate material that has a low moisture vapor transmission rate,

wherein the particulate material comprises an aluminum flake material.

10. The multilayer golf ball of claim 9 , wherein the ratio of particulate material to binder material is about 1:1.