MULTI-LAYER GOLF BALLS HAVING MOISTURE BARRIER LAYERS BASED ON POLYALKENAMER COMPOSITIONS
Golf balls having a dual-core comprising an inner core and outer moisture barrier core layer are provided. The outer core help prevent moisture from penetrating into the inner core. A cover layer, preferably made of a polyurethane or polyurea material, is disposed about the outer core layer. The inner and outer cores are formed of a rubber composition, preferably a polyalkenamer rubber. The polyalkenamer rubber composition may further include other rubbers such as polybutadiene, polyisoprene, ethylene propylene rubber, ethylene propylene diene rubber, and styrene-butadiene rubber. The outer core has a moisture vapor transmission rate (MVTR) lower than that of the cover. In one version, the outer core has a MVTR of 1 grams·mm/m 2 ·day or less, preferably in the range of 0.45 to 0.95 grams·mm/m 2 ·day.
1 . A golf ball, comprising:
a dual-core comprising an inner core and outer moisture barrier core layer, wherein the outer core layer surrounds the inner core, the inner core having a diameter of about 1.30 inches to about 1.58 inches and a compression of about 100 or less, the inner core being formed from a first rubber composition and the outer core layer being formed from a second rubber composition, the second rubber composition comprising a polyalkenamer in an amount of at least 50 weight percent; the outer core layer having a thickness of about 0.01 inches to about 0.20 inches and outer surface hardness of about 80 Shore C or greater, wherein the outer core has a moisture vapor transmission rate lower than that of the cover; and
a cover layer surrounding the outer core layer, the cover layer having a material hardness of about 30 to about 65 Shore D.
2 . The golf ball of claim 1 , wherein the outer core has a moisture vapor transmission rate of 1 grams·mm/m 2 ·day or less.
3 . The golf ball of claim 2 , wherein the outer core has a moisture vapor transmission rate of 0.45 to 0.95 grams·mm/m 2 ·day.
4 . The golf ball of claim 1 , wherein the inner core has a compression of 70 to 90.
5 . The golf ball of claim 1 , wherein the inner core has a surface hardness of 75 to 90 Shore C.
6 . The golf ball of claim 1 , wherein the inner core has a surface hardness of 78 to 87 Shore C.
7 . The golf ball of claim 1 , wherein the outer core layer has a surface hardness of 83 to 97 Shore C.
8 . The golf ball of claim 1 , wherein the outer core layer has a surface hardness of 85 to 93 Shore C.
9 . The golf ball of claim 1 , wherein the inner core has as diameter of 1.45 to 1.57 inches.
10 . The golf ball of claim 1 , wherein the outer core layer has a thickness of 0.025 to 0.060 inches.
11 . The golf ball of claim 1 , wherein the cover layer comprises an inner cover layer and outer cover layer.
12 . The golf ball of claim 11 , wherein the inner cover has a material hardness greater than the material hardness of the outer cover.
13 . A golf ball, comprising:
a dual-core comprising an inner core and outer moisture barrier core layer, wherein the outer core layer surrounds the inner core, the inner core having a diameter of about 1.51 inches to about 1.58 inches and a compression of about 100 or less, the inner core being formed from a first rubber composition and the outer core layer being formed from a second rubber composition, the second rubber composition comprising a polyalkenamer in an amount of at least 50 weight percent; the outer core layer having a thickness of about 0.01 inches to about 0.06 inches and outer surface hardness of about 80 Shore C or greater, wherein the outer core has a moisture vapor transmission rate lower than that of the cover; and
a cover layer surrounding the outer core layer, the cover layer being formed from a composition comprising polyurethane; polyurea; or a hybrid, copolymer or blend of polyurethane and polyurea and having a material hardness of about 30 to about 65 Shore D.
14 . The golf ball of claim 13 , wherein the outer core has a moisture vapor transmission rate of 1 grams·mm/m 2 ·day or less.
15 . The golf ball of claim 14 , wherein the outer core has a moisture vapor transmission rate of 0.45 to 0.95 grams·mm/m 2 ·day.
16 . The golf ball of claim 13 , wherein the cover layer has a thickness of 0.010 to 0.055 inches.
17 . The golf ball of claim 13 , wherein the cover layer has a thickness of 0.020 to 0.040 inches.
18 . The golf ball of claim 13 , wherein the cover layer has a material hardness of 40 to 63 Shore D.
19 . The golf ball of claim 13 , wherein the cover layer comprises an inner cover layer and outer cover layer, the inner cover layer being formed from an olefin-based ionomer copolymer and the outer cover layer being formed from a composition comprising polyurethane; polyurea; or a hybrid, copolymer, or blend of polyurethane and polyurea.
20 . The golf ball of claim 19 , wherein the inner cover has a material hardness of 60 Shore D or greater and the outer cover has a material hardness of 30 to 65 Shore D.