US2025312657A1PendingUtilityA1
Golf balls having cores with increased hardness gradient
Est. expiryJun 14, 2042(~15.9 yrs left)· nominal 20-yr term from priority
A63B 37/0039A63B 37/0063A63B 37/0045A63B 37/0075A63B 37/0033A63B 37/0032A63B 37/00921A63B 37/0092A63B 37/0031A63B 37/00622A63B 37/0051A63B 37/00621A63B 37/0076A63B 37/0043A63B 37/0064
81
PatentIndex Score
0
Cited by
0
References
0
Claims
Abstract
Golf balls having cores with increased hardness gradients are provided. The cores have an increased “positive” hardness gradient (or a “hard-to-soft” hardness) where the outer surface of the core is harder than the center. The increased positive hardness gradient can be achieved by introducing a water-releasing agent into the core rubber formulation during the curing process. The resulting golf balls have reduced spin and sufficient impact durability.
Claims
exact text as granted — not AI-modifiedWhat is claimed is:
1 . A core for a golf ball, comprising:
an outer surface and a geometric center, wherein the core is formed from a reaction product of a base rubber, a curing agent, and a metal sulfate dihydrate, wherein the metal sulfate dihydrate is present in an amount of about 1 phr to about 3 phr, wherein the geometric center and the outer surface each has a hardness and the hardness of the geometric center ranges from about 40 Shore C to about 70 Shore C and the hardness of the outer surface ranges from about 75 Shore C to about 105 Shore C, and wherein the hardness of the outer surface is greater than the hardness of the geometric center to define a positive hardness gradient.
2 . The core of claim 1 , wherein the curing agent comprises an organic peroxide selected from dimethyl terbutyl peroxide, dicumyl peroxide, or combinations thereof.
3 . The core of claim 1 , wherein the metal sulfate dihydrate is calcium sulfate dihydrate.
4 . The core of claim 1 , wherein the curing agent is present in an amount of about 0.25 phr to about 2.5 phr.
5 . The core of claim 1 , wherein the positive hardness gradient is at least 34 Shore C units.
6 . The core of claim 1 , wherein the amount of metal sulfate dihydrate and the number of waters of hydration of the metal sulfate dihydrate are related to the positive hardness gradient, according to equation (I):
2
≤
W
R
A
C
*
W
R
A
WOH
1
-
1
H
Gr
≤
8
,
(
I
)
where WRA C represents the amount of metal sulfate dihydrate in parts per hundred; H Gr represents the positive hardness gradient (Shore C); and WRA WOH represents the number of waters of hydration in the metal sulfate dihydrate.
7 . The core of claim 1 , wherein the base rubber comprises polybutadiene, ethylene-propylene-diene rubber, or a combination thereof.
8 . A dual core for a golf ball, comprising:
an outer core layer disposed over an inner core layer, wherein at least one of the outer core layer or inner core layer has a positive hardness gradient and is formed from a reaction product of a base rubber, a curing agent, and a metal sulfate dihydrate, wherein the metal sulfate dihydrate is present in an amount of about 1 phr to about 3 phr, and wherein the layer formed from the reaction product comprises an inner surface hardness of about 40 Shore C to about 70 Shore C and an outer surface hardness of about 75 Shore C to about 105 Shore C.
9 . The dual core of claim 8 , wherein the metal sulfate dihydrate is calcium sulfate dihydrate, zinc sulfate dihydrate, or a combination thereof.
10 . The dual core of claim 8 , wherein the amount of metal sulfate dihydrate and the number of waters of hydration of the metal sulfate dihydrate are related to the positive hardness gradient, according to equation (I):
2
≤
W
R
A
C
*
W
R
A
WOH
1
-
1
H
Gr
≤
8
,
(
I
)
where WRA C represents the amount of metal sulfate dihydrate in parts per hundred; H Gr represents the positive hardness gradient (Shore C); and WRA WOH represents the number of waters of hydration in the metal sulfate dihydrate.
11 . The dual core of claim 8 , wherein the positive hardness gradient is at least 34 Shore C units.
12 . The dual core of claim 8 , wherein the outer core layer and the inner core layer are formed from the reaction product.
13 . The dual core of claim 8 , wherein the curing agent is an organic peroxide selected from dimethyl terbutyl peroxide, dicumyl peroxide, or combinations thereof.
14 . The dual core of claim 8 , wherein the curing agent is present in an amount of about 0.1 phr to about 3 phr.
15 . A multi-layered core for a golf ball, comprising:
a center and a plurality of core layers formed around the center, wherein at least one of the center or the plurality of core layers has a positive hardness gradient and is formed from a reaction product of a base rubber, a curing agent, and a metal sulfate dihydrate, wherein the metal sulfate dihydrate is present in an amount of about 1 phr to about 3 phr, and wherein the layer formed from the reaction product comprises an inner surface hardness of about 40 Shore C to about 70 Shore C and an outer surface hardness of about 75 Shore C to about 105 Shore C.
16 . The multi-layered core of claim 15 , wherein the center and each of the plurality of core layers is formed from the reaction product.
17 . The multi-layered core of claim 15 , wherein the water releasing agent is calcium sulfate dihydrate.
18 . The multi-layered core of claim 15 , wherein the positive hardness gradient is about 30 Shore C units to about 50 Shore C units
19 . The multi-layered core of claim 15 , wherein the curing agent is an organic peroxide selected from dimethyl terbutyl peroxide, dicumyl peroxide, or combinations thereof.
20 . The multi-layered core of claim 15 , wherein the positive hardness gradient is at least 34 Shore C units.Join the waitlist — get patent alerts
Track US2025312657A1 — get alerts on status changes and closely related new filings.
We store only your email — no account needed. See our privacy policy.