Golf balls having reduced driver spin
Multi-layer golf ball cores having positive hardness and compression gradients and golf balls including these cores are disclosed. The hardness, compression, and diameter relationships in the core assemblage components help to reduce the spin rate of the ball off the driver while still providing desirable performance characteristics in and around the green.
1. A golf ball, comprising:
a core assemblage comprising:
a center having a surface hardness H 1 , a diameter D 1 , and a SCDI compression C 1 , wherein the center comprises a first rubber formulation comprising a first amount of co-agent;
an inner core layer disposed about the center and having a surface hardness H 2 , a diameter D 2 , and a SCDI compression C 2 , wherein H 1 is about 60 percent to about 90 percent of H 2 and Cis about 25 percent to about 60 percent of C 2 , wherein the inner core layer comprises a second rubber formulation comprising a second amount of co-agent, and wherein the first amount is about 30 to about 70 percent of the second amount; and
an outer core layer disposed about the inner core layer and having a surface hardness H 3 , a diameter D 3 , and a SCDI compression C 3 , wherein H 2 is about 60 percent to about 90 percent of H 3 and C 2 is about 40 percent to about 80 percent of C 3 , wherein the outer core layer comprises a third rubber formulation comprising a third amount of co-agent, wherein the second amount is about 50 to 75 percent of the third amount, and wherein
0.1
≤
CA
C
1
-
1
CGr
SCDI
≤
0.2
where CA C represents the weight percent of the first amount in decimal form based on 100 parts of base rubber in the first rubber formulation, and CA C ≤0.2; and CGr SCDI represents a compression gradient (SCDI) of the core assemblage;
an intermediate layer disposed about the core assemblage to form an intermediate ball; and
a cover layer disposed about the intermediate ball.
2. The golf ball of claim 1 , wherein each of the first, second, and third rubber formulations comprise polybutadiene rubber, butyl rubber, or a blend thereof.
3. The golf ball of claim 1 , wherein D 1 is about 60 percent to 80 percent of D 2 and D 2 is about 60 percent to about 80 percent of D 3 .
4. The golf ball of claim 1 , wherein the cover layer has a thickness in the range of about 0.010 to about 0.080 inches.
5. The golf ball of claim 4 , wherein the cover layer comprises a material selected from the group consisting of polyurethanes, polyureas, and hybrids, copolymers, and blends thereof.
6. The golf ball of claim 1 , wherein the intermediate layer comprises an ionomer material.
7. The golf ball of claim 1 , wherein H 1 is in the range of about 60 to about 80 Shore C, H 2 is in the range of about 70 to about 90 Shore C, and H 3 is in the range of about 80 to about 100 Shore C to provide a positive hardness gradient from the center to the outer core layer.
8. The golf ball of claim 1 , wherein the co-agent is one or more metal salts of acrylates, diacrylates, methacrylates, and dimethacrylates, and wherein the metal is selected from magnesium, calcium, zinc, aluminum, lithium, and nickel.
9. The golf ball of claim 1 , wherein the first amount is about 45 to about 60 percent of the second amount and the second amount is about 60 to about 75 percent of the third amount.
10. A golf ball, comprising:
a core assemblage comprising:
a center having a surface hardness H 1 , a diameter D 1 , and a SCDI compression C 1 , wherein the center comprises a first rubber formulation comprising a first amount of co-agent;
an inner core layer disposed about the center and having a surface hardness H 2 , a diameter D 2 , and a SCDI compression C 2 , wherein the inner core layer comprises a second rubber formulation comprising a second amount of co-agent, wherein the first amount is about 30 to about 70 percent of the second amount; and
an outer core layer disposed about the inner core layer and having a surface hardness H 3 , a diameter D 3 , and a SCDI compression C 3 , wherein the outer core layer comprises a third rubber formulation comprising a third amount of co-agent, wherein the second amount is about 50 to 75 percent of the third amount, wherein
0.1
≤
CA
C
1
-
1
CGr
SCDI
≤
0.2
where CA C represents the weight percent of the first amount in decimal form based on 100 parts of base rubber in the first rubber formulation, and CA C ≤0.2; and CGr SCDI represents a compression gradient (SCDI) of the core assemblage, and wherein
0.2
≤
CA
IC
1
-
1
CGr
SCDI
≤
0.2
where CA IC represents the weight percent of the second amount in decimal form based on 100 parts of base rubber in the second rubber formulation, and CA IC ≤0.3;
an intermediate layer disposed about the core assemblage to form an intermediate ball; and
a cover layer disposed about the intermediate ball.
11. The golf ball of claim 10 , wherein H 1 is in the range of about 60 to about 80 Shore C, H 2 is in the range of about 70 to about 90 Shore C, and H 3 is in the range of about 80 to about 100 Shore C to provide a positive hardness gradient from the center to the outer core layer.
12. The golf ball of claim 10 , wherein
0.15
≤
H
1
H
3
C
3
C
1
≤
0.35
.
13. The golf ball of claim 10 , wherein the co-agent is one or more metal salts of acrylates, diacrylates, methacrylates, and dimethacrylates, and wherein the metal is selected from magnesium, calcium, zinc, aluminum, lithium, and nickel.
14. The golf ball of claim 10 , wherein the first amount is about 33 to about 67 percent of the second amount and the second amount is about 60 to about 75 percent of the third amount.
15. A golf ball, comprising:
a core assemblage comprising:
a center having a surface hardness H 1 , a diameter D 1 , and a SCDI compression C 1 , wherein the center comprises a first rubber formulation comprising a first amount of co-agent;
an inner core layer disposed about the center having a surface hardness H 2 , a diameter D 2 , and a SCDI compression C 2 , wherein C 1 is about 30 percent to about 60 percent of C 2 , wherein the inner core layer comprises a second rubber formulation comprising a second amount of co-agent, and wherein the first amount is about 30 to about 70 percent of the second amount; and
an outer core layer disposed about the inner core layer and having a surface hardness H 3 , a diameter D 3 , and a SCDI compression C 3 , wherein the outer core layer comprises a third rubber formulation comprising a third amount of co-agent, wherein the second amount is about 50 to 75 percent of the third amount, wherein C 2 is about 50 percent to about 80 percent of C 3 , wherein
0.1
≤
CA
C
1
-
1
CGr
SCDI
≤
0.2
where CA C represents the weight percent of the first amount in decimal form based on 100 parts of base rubber in the first rubber formulation, and CA C ≤0.2; and CGr SCDI represents a compression gradient (SCDI) of the core assemblage, and wherein
1
2
(
H
1
+
H
2
)
>
1
3
(
H
1
+
H
3
)
and
1
2
(
H
1
+
H
2
)
>
1
3
(
H
2
+
H
3
)
;
an intermediate layer disposed about the core assemblage to form an intermediate ball; and
a cover layer disposed about the intermediate ball.
16. The golf ball of claim 15 , wherein H 1 is in the range of about 60 to about 80 Shore C, H 2 is in the range of about 70 to about 90 Shore C, and H 3 is in the range of about 80 to about 100 Shore C to provide a positive hardness gradient from the center to the outer core layer.
17. The golf ball of claim 15 , wherein the cover layer comprises a material selected from the group consisting of polyurethanes, polyureas, and hybrids, copolymers, and blends thereof.
18. The golf ball of claim 15 , wherein the intermediate layer comprises an ionomer material.
19. The golf ball of claim 15 , wherein the co-agent is one or more metal salts of acrylates, diacrylates, methacrylates, and dimethacrylates, and wherein the metal is selected from magnesium, calcium, zinc, aluminum, lithium, and nickel.
20. The golf ball of claim 15 , wherein the first amount is about 45 to about 60 percent of the second amount and the second amount is about 60 to about 75 percent of the third amount.