1
HIGH COR GOLF BALL USING ZINC
DIMETHACRYLATE
CROSS-REFERENCE TO RELATED
APPLICATIONS 5
This application is a continuation of U.S. patent application Ser. No. 10/740,530, filed Dec. 22, 2003, now U.S. Pat. No. 7,342,073, the disclosure of which is incorporated by 10 reference herein in its entirety.
where R^Rs can be substituted or unsubstituted Cj-Cg alkyl groups; halogen groups; thiol groups (—SH), carboxy
FIELD OF THE INVENTION lated groups; sulfonated groups; and hydrogen; in any order.
In one embodiment, the at least one structural layer is a
The present invention relates to the use of zinc dimethacry- core, an intermediate layer or a cover, wherein the composi
late in golf ball compositions. In particular, the invention tion is disposed in at least a portion of the at least one struc
relates to resilient golf balls and portions thereof including mral layer- ^ zinc dimethacrylate may be present in an
compositions containing zinc dimethacrylate and zinc pen- 20 amount from about 0.01 pph to about 100 pph and the at least
^ ,, ^ • , , , ^ , j- , • one halogenated organosulfur compound ol formula I is tachlorothiophenol, and methods for making same. . . f „ 1+^^11+1+^1
r ° present in an amount from about 0.01 pph to about 50 pph.
In one embodiment, the at least one halogenated organosulfur compound of formula I is selected from the group
25 consisting of pentafluorothiophenol; 2-fluorothiophenol;
Conventional golf balls can be divided into several general 3-fluorothiophenol; 4-fluorothiophenol; 2,3-fluorothiophe
classes: (a) solid golf balls having one or more layers, and (b) nol; 2,4-fluorothiophenol; 3,4-fluorothiophenol; 3,5-fluo
wound golf balls. Solid golf balls include one-piece balls, rothiophenol 2,3,4-fluorothiophenol; 3,4,5-fluorothiophenol;
which are easy to construct and relatively inexpensive, but 2,3,4,5-tetrafluorothiophenol; 2,3,5,6-tetrafluorothiophenol;
have poor playing characteristics and are thus generally lim- 30 4-chlorotetrafluorothiophenol; pentachlorothiophenol;
.+ , .. . „ . ^ . 2-chlorotmophenol; 3-chlorothiophenol; 4-chlorothiophe
lted for use as range balls. Iwo-piece balls are constructed , ,. ,. , , „ . , , . , , - . , ,
,, ,. , , nol; 2,3-chlorothiophenol; 2,4-chlorothiophenol; 3,4-chlo
with a generally solid core and a cover and are generally rothiophenol; 3,5-chlorothiophenol; 2,3,4-chlorothiophenol;
popular with recreational golfers because they are very 3,4,5-chlorothiophenol; 2,3,4,5-tetrachlorothiophenol; 2,3,5,
durable and provide maximum distance. Balls having a two- 35 6-tetrachlorothiophenol; pentabromothiophenol; 2-bro
piece construction are commonly formed of a polymeric core mothiophenol; 3-bromothiophenol; 4-bromothiophenol; 2,3
encased by a cover. Solid golf balls also include multi-layer bromothiophenol; 2,4-bromothiophenol; 3,4
golf balls that are comprised of a solid core of one or more bromothiophenol; 3,5-bromothiophenol; 2,3,4
layers and/or a cover of one or more layers. These balls are bromothiophenol; 3,4,5-bromothiophenol; 2,3,4,5
regarded as having an extended range of playing characteris- 40 tetrabromothiophenol; 2,3,5,6-tetrabromothiophenol;
tics. These balls are generally easy to manufacture, but are pentaiodothiophenol; 2-iodothiophenol; 3-iodothiophenol;
, ^ . ^. 4-iodothiophenol; 2,3-iodothiophenol; 2,4-iodothiophenol;
regarded as having limited playing characteristics. , . . , ^ . , , ' . . , ^ . , ,' . . , I. ,
3,4-iodothiophenol; 3,5-iodothiophenol; 2,3,4-iodothiophe
A variety of golf balls designed to provide a wide range of noi; 3,4,5-iodothiophenol; 2,3,4,5-tetraiodothiophenol; 2,3, playing characteristics, i.e., the compression, velocity, "feel," 45 5,6-tetraiodothiophenol; and their metal salts. In a preferred and spin, that can be optimized for various playing ability, are embodiment, the at least one halogenated organosulfur cornknown in the prior art. Typical golf ball construction includes pound of formula I is a metal salt of Zn, Ca, Ba, Cd, Sn, Mg, a core formed from polybutadiene that is chemically and Mn. In another preferred embodiment, the at least one crosslinked with zinc diacrylate and/or other similar halogenated organosulfur compound of formula I is a metal crosslinking agents 50 salt of Zn'In yet another preferred embodiment, the at least
one halogenated organosulfur compound of formula I is zinc
However, it is desirable to have golf ball compositions that pentachlorothiophenol alternative crosslinkers, such as zinc dimethacrylate, without xhe free radical source may be di.tert.amyl per0xide, di(2
compromising golf ball payability. The compositions of the tert-butylperoxyisopropyl)benzene peroxide or a,a-bis(tert
present invention provided golf balls with improved coeffi- 55 butylperoxy) diisopropylbenzene, l,l-bis(tert-butylperoxy)
cient of restitution ("CoR") and increased compression using 3,3,5-trimethylcyclohexane or l,l-di(tert-butylperoxy) 3,3,
zinc dimethacrylate. 5-trimethyl cyclohexane, dicumyl peroxide, di-tert-butyl
peroxide, 2,5-di-(tert-butylperoxy)-2,5-dimethyl hexane,
SUMMARY OF THE INVENTION n-butyl-4,4-bis(tert-butylperoxy)valerate, lauryl peroxide,
60 benzoyl peroxide, tert-butyl hydroperoxide, or any mixture thereof.
The present invention is directed to a golf ball comprising in one embodiment, the composition further comprises one
at least one structural layer formed from a composition that ormore additional crosslinking agent selected from the group
comprises a resilient polymer component, a free radical consisting of a metallic salt of an unsaturated acid monomer
source, zinc dimethacrylate and at least one halogenated 65 and a metallic salt of a monocarboxylic acid. In another
organosulfur compound having the following general for- embodiment, the cover comprises one or more homopoly
mula I: meric or copolymeric cover materials selected from the group
