Document bYJJ0KGYV1p9zMXMKnd6j6rZ
United States Patent [i9]
Saito et al.
[ii] 4,295,652 [45] Oct. 20, 1981
[54] GOLF BALL
[75] Inventors: Tasuku Saito, Tokorozawa; Tatomu Noma, Higashimurayama; Tsutomu Matsunaga, Iruma; Nagayoshi Naito, Nagoya; Chiaki Tanaka, Chita; Motoki Hiratsuka, Nagoya, all of Japan
[73] Assignees: Bridgestone Tire Co., Ltd.; Toray Industries, Inc., both of Tokyo, Japan
[21] Appl. No.: 119,640
[22] Filed:
Feb. 8,1980
[30] Foreign Application Priority Data Feb. 15, 1979 [JP] Japan ...................................... 54-16339
[51] Int. Q.3............................................ A63B 37/12 [52] U.S. a................................. 273/235 R; 273/224;
260/998.14; 525/533 [58] Field of Search.................. 260/998.14; 525/533;
273/233, 235 R, 58 J, DIG. 9
[56] References Cited
U.S. PATENT DOCUMENTS
3,784,520 1/1974 Hoeschele....................... 525/533 3,940,146 2/1976 Little ......................... 260/998.14
Primary Examiner--Allan Lieberman Attorney, Agent, or Firm--Austin R. Miller
[57] ABSTRACT
A golf ball having a thread-wound core and a cover formed of a block copolyetherester comprising (A) a terephthalic acid unit, (B) a 1,4-butanediol unit, (C) a unit of a dicarboxylic acid, other than terephthalic acid, or a short-chain diol, other than 1,4-butanediol, having a number-average molecular weight of not more than 300 and (D) a poly(alkylene oxide)glycol unit having a number-average molecular weight of from 500 to 3000. Said golf ball exhibits excellent impact resilience and also exhibits good cutting resistance and "click".
7 Claims, No Drawings
4,295,652
1
(C) dicarboxylic acids, other than terephthalic acid,
GOLF BALL
or diols, other than 1,4-butanediol, having a low molec
ular weight, and
The present invention relates to a golf ball having a
(D) poly(alky!ene oxide)glycol having a number-
thread-wound central core and, more specifically, it 5 average molecular weight of from 500 to 3000.
relates to a golf ball in which a block copolyetherester
In the block copolyetherester of the present inven
having a specified structure is used as an outer cover for tion, short-chain ester hard segments are composed of
the thread-wound central core.
the copolyester which is derived from (A) terephthalic
Properties which are required for the cover of a golf acid, (B) 1,4-butanediol and (C) dicarboxylic acids,
ball are impact resilience sufficient to give a satisfactory 10 other than terephthalic acid, or diols, other than 1,4-
flight distance, cutting resistance, qualitative feeling butanediol, having a low molecular weight.
such as "click" when the ball is hit by the club, a good
The dicarboxylic acids, other than terephthalic acid,
affinity for the thread-wound (or solid) core during the used as the component (C) in the present invention
molding process and the like.
include: aromatic dicarboxylic acids such as isophthalic
Used heretofore, as the cover materials of golf balls, 15 acid, phthalic acid, naphthalene-2,6-dicarboxylic acid,
are mainly trans-1,4-polyisoprene, such as guttapercha naphthalene-2,7-dicarboxylic acid, diphenyl-4,4'-dicar-
and balata. However, since these materials are expen boxylic acid, diphenoxyethane dicarboxylic acid and
sive, various attempts have been made to develop new 5-suIfoisophthalic acid; alicyclic dicarboxylic acids such
materials which can substitute for those materials as the as 1,4-cyclohexane dicarboxylic acid; and aliphatic di
cover materials of golf balls. Among these new materi- 20 carboxylic acids such as succinic acid, oxalic acid,
als, metallic salts of copolymers of ethylene and a,(iunsaturated carboxylic acids, that is, so-called iono-
adipic acid, sebacic acid, dodecanoic acid and dimer acid. These acids can be used alone or in any mixture
mers, are used as the replacement for balata, on a com thereof. It should be noted that ester-forming deriva
mercial scale. However, although the ionomers exhibit tives of these dicarboxylic acids such as, for example,
an especially excellent cutting resistance, the "click" 25 the lower alkyl esters, the aryl esters, the carbonate (or
and impact resilience thereof are inferior to those of the carbonic acid ester) and the acid halides can also be
golf balls having the balata cover.
used as the component (C) in the present invention.
Accordingly, the objects of the present invention are
The diols, other than 1,4-butanediol, used as the com
to obviate the afore-mentioned promblems of the prior ponent (C) in the present invention include those having
art and to provide an improved golf ball which exhibits 30 a molecular weight of 300 or less. Examples of such
superior impact resilience and also has satisfactory diols are: aliphatic diols such as ethylene glycol, tri
properties, other than the impact resilience, which are methylene glycol, pentamethylene glycol, hexamethyl-
required for golf balls.
ene glycol, neopentyl glycol and decamethylene glycol;
Other objects and advantages of the present invention alicyclic diols such as 1,1-cyclohexane dimethanol, 1,4-
will be apparent from the following description.
35 cyclohexane dimethanol and tricyclodecane dime
In accordance with the present invention, there is thanol; and diols containing aromatic group(s) such as
provided a golf ball comprising a thread-wound central xylylene glycol, bis(p-hydroxy)diphenyl, bis(p-hydrox-
core and an outer cover for the core, said cover being yphenyl)propane, 2,2-bis 4-(2-hydroxyethoxy)phenyl]-
formed of, as a main ingredient, a block copolyether propane, 2,2-bis[4-(2-hydroxyethoxy)phenyl]propane,
ester comprising (A) a terephtalic acid unit, (B) a 1,4- 40 bis[4-(2-hydroxy)phenyi]sulfone and, l,l-bis[4-(2-
butanediol unit, (C) a unit of a dicarboxylic acid, other hydroxyethoxy)phenyl]cyclohexane. These diols can be
than terephthalic acid, or a short-chain diol, other than used alone or in any combination thereof. It should be
1,4-butanediol, having a number-average molecular noted that ester-forming derivatives of these diols such
weight of not more than 300 and (D) a po!y(alkylene as, for example, the acetylated derivatives and the alkali
oxide)glycol unit having a number-average molecular 45 metal salts can also be used as the component (C) in the
weight of from 500 to 3000, the amount of the compo present invention.
nent (C), in terms of mol ratio to the component (A) or
Among the components (A), (B) and (C) which form
(B) being 25/75 through 60/40 and the amount of the the hard segment of the block copolyetherester of the
component (D) being 35 through 70% by weight based present invention, the components (A) and (B) serve as
on the total weight of the copolymer.
50 the components to improve the impact resilience, the
The golf ball according to the present invention has hardness and the cutting resistance. These properties
an advantage in that the flight distance of the ball is are required for the cover of golf balls. However, block
increased due to the high impact resilience thereof. copolyetherester having the hard segment derived from
Furthermore, since the specific gravity of the cover only the components (A) and (B) exhibits a high melting
materia] of the present invention is larger than that of 55 point and poor moldability. For this reason, an appro
the conventional cover materials, such as balata or iono- priate amount of the component (C) is added, according
mer, the weight of the core of the golf ball should be to the present invention. The addition of the component
reduced, so that the moment of inertia of the golf ball (C) also increases the cutting resistance of the golf balls.
becomes larger compared with the conventional balls. However, when the addition amount of the component
Thus, when the ball is struck by the club, appropriate 60 (C) is too large, an unpreferable decrease in the hard
spin is put on the ball and the trajectory of the ball ness of the copolyetherester is caused. Furthermore, the
becomes stable compared with the conventional balls. cutting resistance and the initial velocity are also unde
As mentioned hereinabove, the block copolyether sirably decreased. For these reasons, the component (C)
ester used, as the cover for the thread-wound core, in should be used in an amount of, in terms of moi ratio to
the present invention comprises the following four com- 65 the component (A) or (B), 25/75 through 60/40, and
ponents:
preferably 32/68 through 50/50.
(A) terephthalic acid
The component (D), i.e. poly(alkylene oxide)glycol
(B) 1,4-butanediol
having a number-average molecular weight of from 500
4,295,652
34
to 3000 forms the soft segments of the block copolyeth- ylic acid, glycerine, pentaerythritol and the esters and
erester. Examples of those poly(alkylene oxide)glycol acid anhydrides thereof.
are polyethylene glycol, poly(l,2- and 1,3-propylene
The composition used in the formation of the golf ball
oxide)glycol, poly(tetramethylene oxide) glycol, co covers of the present invention can additionally contain
polymer of ethylene oxide and propylene oxide and the 5 various conventional additives^There may be used
copolymer of ethylene oxide and tetrahydrofuran. fillers exemplified by graphite, chopped glass fiber,
These poly(alkylene oxide)glycols can be used alone or in any combination thereof. Among these compounds,
the most preferable polyfalkylene oxide)glycol is poly(-
chopped synthetic fiber such as polyester fiber, inor ganic fibrous filler such as asbestos, glass flake, titanium
dioxide, zinc oxide, magnesium oxide, finely divided
tetramethylene oxide)gIycol from the point of view of 10 silica hydrate, lead carbonate, calcium carbonate, clays,
the properties, especially, the tear strength and the im alumina, litharge and baryte, nucleating agents such as
pact resilience of the material. The amount of the soft alkaline earth metal carbonates, the sodium salts of
segments in the block copolyetherester may be widely higher fatty acids, the sodium salt of montan wax acid
varied depending on, for example, the copolymerization and powdered polybutylene terephthalate, and lubri
ratio of the polyester hard segments and the desired 15 cants such as hydrocarbon type waxes, fatty acids, fatty
hardness of the golf balls. However, the decrease in the acid amides, bis-fatty acid amides, ester waxes and me
impact resilience and the decrease in the hardness are tallic soaps.
caused in the case where the amount of the component
Conventional heat and radiation stabilizing agents,
(D) is either too large or too small. Accordingly, the such as antioxidants and ultraviolet light absorbents
amount of the component (D) in the block copolyether 20 (UV absorbers), can also be incorporated into the com
ester is within the range of from 35 to 70% by weight,
and preferably 35 to 60% by weight, based on the total
weight of the block copolyetherester.
The copolyetherester comprising said four compo nents (A), (B), (C) and (D) can be prepared in any con
25
ventional method. For instance, the lower alcohol dies
ter of dicarboxylic acid, an excess amount of the glycol
having a low molecular weight and an excess amount of
the poly(alkylene oxide)glycol are subjected to an ester interchange reaction in the presence of a catalyst, and 30
positions for molding the golf ball covers of the present invention.
The heat stabilizing agents which can be used in the present invention include, for example, various hin dered phenols, such as 4,4'-bis(2,6-ditertiary butyl phe nol), l,3,5-trimethyl-2,4,5-tris(3,5-ditertiary butyl-4hydroxybenzyl)benzene, tetrakis[methylene-3(3,5-ditertiary butyl-4-hydroxy phenyl)propionate]methane and N, N'-hexamethylene-bis(3,5-ditertiary butyl-4-hydroxyhydro cinnamic acid amide); aromatic amines such as N, N'-bis(/?-naphtyl)-p-phenylene diamine and 4,4'-
the resultant reaction products are then subjected to a polycondensation reaction. Alternatively, the dicarbox
bis(4-a,a-dimethyl benzyl)diphenyl amine; sulfur com pounds such as dilauryl thiodipropionate; phosphorous
ylic acid is esterified in the presence of a catalyst with compounds; alkaline earth metal oxides; the nickel salt
the glycol and the polyfalkylene oxide)glycol and the 35 of the Schiff bases. Examples of the radiation stabilizing
product so obtained is subjected to a polycondensation agents are substituted benzophenones, benzotriazoles
reaction. Further, after polybutylene terephthalate is and piperidine compounds such as bis(2,2,6,6-tetrameth-
previously prepared in a known manner, the other di yI-4-piperidine)sebacate and 4-benzoyloxy-2,2,6,6-tet-
carboxylic acid and the diol or the polyfalkylene oxide)- ramethyl piperidine.
glycol are added to the polybutylene terephthalate to 40 The golf balls of the present invention can be manu
effect the randomization of polybutylene terephthalate factured in any conventional manner. For instance,
with the components. Furthermore, to the previously after the above-mentioned various ingredients are
prepared polyester, such as copolyetherester, the other added to the block copolyetherester to prepare the
copolyester is added to effect the randomization of both composition, the composition thus obtained is molded
copolyesters by an ester interchange reaction.
45 to a sheet and, then, the sheet is fabricated or shaped in
As the catalysts commonly used in the esterification a cold state to form half-cups or half-shells. However,
or ester interchange reaction and the polycondensation the half-shells can be advantageously and directly injec
reaction, titanium catalysts can be advantageously used tion molded, without being formed into sheets, from the
due to the fact that good results are obtained. Espe composition containing the block copolyetherester. A
cially, tetraalkyl titanate, such as tetrabutyl titanate, 50 thread-wound core is placed between two half-shells
metal salts of titanium oxalate, such as potassium tita and the ball assembly thus obtained is, then, molded
nium oxalate and the like can be preferably used. Exam under a pressure of at least 0.5 ton per ball at a tempera
ples of the other catalysts used in the preparation of the ture of 130 through 180 C. to form the golf ball of the block copolyetherester of the present invention are tin present invention. Otherwise, the golf ball of the pres compounds, such as dibutyltin oxide and dibutyltin 55 ent invention can also be prepared by placing the
laurate, and lead compounds, such as lead acetate.
thread-wound core in the center of a mold cavity and
In the block copolyetherester of the present inven then injecting the composition containing the block
tion, a portion of the dicarboxylic acids or the glycols copolyetherester to form the golf ball of the present
can be replaced with polycarboxylic acids or polyfunc invention.
tional hydroxy compounds and oxyacids. These copoly 60 Since the specific gravity of the block copolyether
merized polyfunctional components effectively serve as ester used in the present invention is larger than those of
an agent for increasing the viscosity of the block copo the balata and ionomers which are the conventional
lyetherester of the present invention. These polyfunc cover materials, the total weight of the golf ball is ad
tional components can be used in an amount of 3 mol% justed by reducing the weight of the thread-wound core
or less based on the total weight of the block copolyeth 65 so as to maintain the total weight constant. The conven
erester. Examples of such polyfunctional components tional golf ball core is composed of a rubber sphere
are trimellitic acid, trimesic acid, pyromellitic acid, filled with a liquid substance therein or a solid sphere
benzophenone tetracarboxylic acid, butane tetracarbox- made of an elastic substance such as cis-polybutadiene.
4,295,652
However, according to the present invention, since the Thus, golf balls having a weight of 45.5 g and a diame
amount of the fillers contained in the core, such as zinc ter of 41.15 mm were obtained.
oxide, titanium oxide, calcium carbonate and barium
The initial velocity and the trajectory of the balls thus
sulfate is reduced to adjust the total weight of the golf obtained were evaluated by using a golf ball hitting test
balls, the impact resilience of the golf ball core is desir- 5 machine manufactured by TRUE TEMPER Corp. The
ably increased. Furthermore, since the moment of iner test was carried, out under the conditions of the club
tia of the ball thus manufactured becomes high, when head speed of 45 m/sec (a No. 1 wood club was used)
the ball is struck by the club, appropriate spin is put on and the ball temperature of 20 C. The results are shown
the ball and, therefore, the trajectory of the ball be in Table 1 below. The cutting resistance was also deter
comes stable.
' 10 mined by using the same test machine as described
The present invention is further illustrated in detail above. The marks caused in the surface of the ball after
by, but is by no means limited to, the following exam having been hit with a No. 7 iron club at a pressure of
ples in which all parts and percentages are expressed on 7 kg/cm2 were observed with the naked eye. The result
a weight basis, unless otherwise specified.
are also shown in Table 1 below.
EXAMPLE 1
15 The initial velocity, the trajectory, the cutting resis tance and the "click" property of the balls thus evalu
A block copolyetherester was prepared as follows ated were all good and satisfactory.
from (A) terephthalic acid, (B) 1,4-butanediol, (C) isophthalic acid and (D) poly(tetramethylene oxide glycol)
EXAMPLES 2 THROUGH 7
having a number-average molecular weight of 1000. 20 Various copolyetheresters were prepared in a manner
Into a glass flask having a stainless steel stirrer with as described in Example 1, except that the contents of
helical ribbon type screw, 108 parts of terephthalic acid the components (C) and (D) were changed as shown in
135 parts of 1,4-butanediol, 58 parts of isophthalic acid Table 1. Golf balls were prepared from the copolyeth
and 147 parts of polyftetramethylene oxide)glycol hav eresters thus obtained and evaluated in a manner as
ing a molecular weight of about 1000 were placed to- 25 described in Example 1. The properties of the resins and
gether with 0.08 parts of tetrabutyl titanate. The mix the properties of the golf balls so obtained are shown in
ture was heated with stirring at 210 C. for 2 hours, Table 1 below.
while distilling off water from the reaction mixture. The
As is clear from the results shown in Table 1, the
reaction temperature was then raised to 245 C. and the initial velocities of the balls prepared in Examples 1
pressure on the system was reduced to 0.1 mmHg for a 30 through 7 are larger than those of commercially avail
period of 60 minutes. Polymerization was continued for able golf balls having baiata covers or Surlyn covers
3 hours under these conditions. The specific gravity of (Please refer to the following Comparative Examples 5
the block copolyetherester thus obtained was 1.18 and and 6).
the melting point thereof was 139* C. The content of the component (D) based on the total copolymer weight 35
COMPARATIVE EXAMPLE 1 THROUGH 4
was 40%.
Copolyetheresters were prepared in a manner as de
3 Parts of titanium dioxide was added, as a whitening scribed in Example 1, except that the contents of the
agent, to 100 parts of the block copolyetherester. The components'(C) and (D) were changed. Golf balls were
composition thus obtained was mixed and, then, molded manufactured from these copolyetheresters and evalu
on an injection machine having a cylinder temperature 40 ated in a manner as described in Example 1. The results
of 180 C. to form covers in the form of half-shells are shown in Table 1.
TABLE 1
Example
Comparative Example
1234567 1
2
34
Resin Compsirion
Resin Property
Isophthalic Acid/ Terephthalic Acid (mol ratio) Content of Component (D)* (%) Specific gravity Melting Point (*C) JIS Hardness Resilience {%) Initial Velocity (m/sec)
35/65 40/60 40/60 30/70 30/70
40
1.18 139 91 56.1 67.2
40
1.17 128 91 54.5 67.1
50
1.15 122 86 59.0 66.8
50
1.16 147 89 64.2 67.3
40
1.18 152 92 57.5 66.8
Ball Cutting Resistance
Property
Click Trajectory (compared with baiata bail) Ball Weight
good
good good
good
good good
excellent good good
good
good good
good
good good
45.5
45.7
45.3
45.6
45.6
poly(tetramethylene oxide)glycol having a number-average molecular weight of about 1000
30/70
65 1.11 115 84 60.0 67.3
good good good
45.2
55/45
40 1.17 105 86 48.0 67.0
good
good good
45.6
45/55
20/80
0/100
30 30
65
1.20 132 90 42.5 66.3
good
1.21 180 94 42.0 could not be molded
--
1.12 179 92 63.5 could not be molded --
good good
--
--
45.6
--
--
20/80
50 1.16 165 90 59.5 67.7
bad good good
45.6
having a wall thickness of 2 mm.
The golf balls were then prepared by placing a thread-wound core mainly containing, cis-1,4- 65
EXAMPLE 8
polybutadiene between the two half-shells and, then,
A block copolyetherester having a specific gravity of
molded in a mold for golf balls under a pressure of 1.5 1.18 and a melting point of 142 C. was prepared from
ton per ball, at a temperature of 165 C. for 2 minutes. terephthalic acid, phthalic acid, 1,4-butanediol and
4,295,652
78
poly(tetramethylene oxide)glycol in a manner as de weight of from 500 to 3000, the amount of the compo
scribed in Example 1. The ratio of terephthalic acid to nent (C), being 25/75 through 60/40 in terms of mol
the phthalic acid in the copolyetherester was 60/40 ratio to either component (A) or (B), and the amount of
(mol ratio) and the content of poly(tetramethylene ox- the component (D) being 35 through 70% by weight
ide)glycol was 40% by weight.
5 based on the total weight of the copolymer.
From the block copolyetherester thus obtained, golf
2. A golf ball as claimed in claim 1, wherein said
balls having a weight of 4S.6 g were manufactured and dicarboxylic acid, other than terephthalic acid, is se
evaluated in a manner as described in Example 1. The lected from the group consisting of isophthalic acid,
results are as follows.
phthalic acid, naphthaiene-2,6-dicarboxylic acid, naph
10 thalene-2,7-dicarboxylic acid, diphenyl-4,4'-dicarboxy-
Initial Velocity (m/sec) Cutting Resistance "Click" Trajectory (compared with Balata Ball)
66.9 Good Good Good
lic acid, diphenoxyethane dicarboxylic acid and 5-sul-
foisophthalic acid. 3. A golf ball as claimed in claim 1, wherein said
dicarboxylic acid, other than terephthalic acid, is se 15 lected from the group consisting of 1,4-cyclohexane
COMPARATIVE EXAMPLE 5
dicarboxylic acid, succinic acid, oxalic acid, adipic acid, sebacic acid, dodecanoic acid and dimer acid.
Commercially available golf balls each comprising a
4. A golf ball as claimed in claim 1, wherein said diol,
thread-wound core and a balata cover (the diameter other than 1,4-butanediol, is selected from the group was 41.20 mm and the weight was 45.3 g) were evalu 20 consisting of ethylene glycol, trimethylene glycol, pen-
ated in a manner as described in Example 1. The initial tamethylene glycol, hexamethylene glycol, neopentyl
velocity was 66.1 m/sec. The cutting resistance and the glycol and decamethylene glycol.
"click" thereof were good.
5. A golf ball as claimed in claim 1, wherein said diol,
other than 1,4-butanediol, is selected from the group
COMPARATIVE EXAMPLE 6
25 consisting of 1,1-cyclohexane dimethanol, 1,4-cyclohex
Commercially available golf balls each comprising a ane dimethanol and tricyclodecane dimethanol.
thread-wound core and an ionomer cover (the diameter
6. A golf ball as claimed in claim 1, wherein said diol,
was 41.15 mm and the weight was 45.4 g) were evalu other than 1,4-butanediol, is selected from the group
ated in a manner as described in Example 1. The initial velocity was 66.0 m/sec. The cutting resistance was
30
consisting of xylylene glycol, bis(p-hydroxy)diphenyi, bis(p-hydroxyphenyl)propane, 2,2-bis[4-(2-hydroxye-
good, but the "click" was too sharp.
thoxy)phenyl]propane, bis[4-(2-hydroxy)phenyl]sul-
What we claim is:
fone and l,l-bis[4-(2-hydroxyethoxy)pheny^cyclohex
1. A golf ball comprising a thread-wound central core ane.
and an outer cover formed of, as a main
for the core, said cover being ingredient, a block copolyether
35
7. A golf ball as claimed in claim 1, wherein said poly(alkylene oxide)glycol unit is derived from polyeth
ester comprising (A) a terephthalic acid unit, (B) a 1,4- ylene glycol, poly(1,2-propylene oxide)glycol, poly( 1,3-
butanediol unit, (C) a unit of a dicarboxylic acid, other propylene oxide)glycol, poly(tetramethylene oxide)-
than terephthalic acid, or a short-chain diol, other than glycol, a copolymer of ethylene oxide and propylene
1,4-butanediol, having a number-average molecular oxide and a copolymer of ethylene oxide and tetrahyweight of not more than 300 and (D) a poly(alkylene 40 drofuran.
oxide) glycol unit having a number-average molecular
45
50
55
60
65