Note: Descriptions are shown in the official language in which they were submitted.
~s~s~ l
The present invention relat2s to an improvement
in golf clubs known as "wood.s." "Woods" comprise a
shaft,.a club head.block and. usually an insert on
the striking face of the club head block. The
improvement of the present inv~ntion comprises a
polyurethane.insert on the striking face of the golf
- club. When all other conditions remain the same the
golf club with the polyurethane insert will drive
a golf ball ~ur~her than a s~andard. golf club.
.D In the game of golf it is usually desired. to get
the greatest possible d.istance with the golf clubs
known as "wood.s." While many changes have been mzd.e .
in golf balls in ord.er to increase the d.istance they
will travel, the applicants have d.iscovered. a change
~ which can be mad.e in the golf club in ord.er to increase
~ ~ the d.istance which the golf-ball will travel. Hereto-
fore, many different materials have been tried. for
the insert in golf club head.s, including ivory, ste~l,
aluminum and. many d.ifferent plastic compositions. In
~0 choosing the insert, current thinking is that it should ~.
be as hard. as possible so that no dynamic losses of :
- .
. . energy take place when the insert impacts the ball. -
Commonly used. materials today ~or the insert are
. . laminated. phenolics which are quite hard. materials
as is exemplified by the fact that they usually have : -
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.
,
.
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a Rocl~well hardness from about M90-120 for typical
golf club inser-ts. .
The applicants have now discovered. that it is
not always necessar~ to use a hard. material for -~he
insert and that, in fact, there is advantage in using
polyurethane which is a relatively soft material with
a Shore D hardness up to about 80. Quite surprisingly,
the resilience of the polyurethane seems to impart
- ad.d.itional energy to the golf ball rather than causing
O losses of energy as was previously thought to be true ¦
of relat;vely soft ~aterials. .
The polyurethanes which were useful in the practice
of the present ir.vent~on are the uret:hane pre-polymers
.. , - i
mad~ from polyesters ~r polyethers wi~h d.iisocyanate~
: Although any d.iisocyanate may be employed., the preferred.
diisocyanates are 2,4 tolylene d.iisocyanate (TDI), -
. 4~4' d.iphenylmethane diisocyanate (MDI), and. 3,3'
~: dimethyl 4-,4' biphenylene d.iisocyanate (also kno~n as
3,3' dimethyl 4,4' biphenyl d.iisocyanate) (TODI). The
!O polyether part of the pre-polymer is preferably a poly-
alkylene ether glycol having an average molecular
weight of less than 1,000 and. having from about 4 to
about 8 carbon atoms in the alkylene group. Best
.~ results have been obtained. with polytetramethylene . .`
I ethe~r glycol~ The preferred. polyesters in the pre-polymer., 3
, ' '
i8~ i
are polycondensation products of linear dicar~oxyllc
acids and d.ihydric alcohols which yield. a polyester
with alcoholic hydroxy terminal groups. Best
results have been obtained with the polycondensation
product of die-thylene glycol and adipic acid..
The pre-polymer is cured with either a polyol or
an amine-type curing agent. The polyol c~ri.ng agents
may be either d.i-functional, tri-functional or tetra-
functional but best results have been ach~.eved.with
~O the tri-functional and. tetra-func~ional polyol curing
agents. Examples of polyol type curing agents useful in
the practice of the present invention are triisopropanol~ -
Emine (TIPA) and trimethylol propane (T~). Best
` results have bePn obtained. with the '~P. As to the :~
amine-type curing agents, there must be at least ~lo
amine groups present and best results have been obtained.
with aroma~ic d.iamine~. Typical amine-type curing
agents which are use~ul in the practice of the present
~ :invention are: 3,3' dichlorobenzid.ene; 3,3' dichloro, -
'O 4,4' d.iamino diphenyl methane (MOCA); N,N,N'~N' tetrakis
(2-hydroxy propyL) ethylene d.iamine (sold by Wyand.otte .. :
und.er the trade name Quadrol); and. Curalon L which is
Uniroyal Inc.'s brand.name for a mixture of aromatic
diamines. ........................................................... .
In forming the insert oE the present invention
4
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, . .. .. .. . .. . . .. ... . .
. . , . . ... , . .. ~ ..
.. ..
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the pre-polymer and the curing agenL a e mixed. in an
equivalent weight ratio of 1~ 20% and.best results
h~ve been obtained with an equivalent weight ratio
of 1:1~ 10%. The amount of curing agent to be ad.ded. .
is computed. in the following formula:
;.
C = (Ec) (%I)
(EI)
w~erein: '
C = the parts of curing agent to be employed. .
.0 per 100 parts of prepolymer;
~ EI = the equivalent weight of the isocyanate
:: ~ linkage in the prepolymer (which will be
- 42.0);
.%I = the percentage b~ weight o~ available
: .. isocyanate in the prepol~y~er; and.
~ -: .
EC = the equivalent weight of the curing agent
(d.etermined.by d.ividing the molecular
weight of the curing agent by the number
- : of sites available for curing).
~ . . : .
.-.~0 The above formula will result in an equivalent weight.
ratio of l:l for curing agent to prepolymer. The
.. amount of curing agent may then be varied. ap to 20% ~ ~
~n either d.irection. A computation accord.ing to the ~ -
abave ormula is given in Example 1.
-5~
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As a general rule the pre-polymer and the curing
agent are thoroughly mixed at a temperature ranging , ,
from arn~ient to 250F. and then are formed into the
shape of an ins~rt as by open casting, compression
molding, transfer molding or other known techniques.
The insert is then cured and this is,typically at
: from about 200F. to about 300F. for about 1 to about
24 hours. The curing time can be d.ecreased in known
manner by using catalysts (e.g., stannous octoate where
,'0 the polyol-type curing agent is used,).
, . - ~ile the polyurethane insert has been d.escribed, . ~ :
.... , ~
with respect to particular pre-poly~ers and. curing
.
''' ~ agents, it has been found. that a pol~J~reLhane insert , , .'`
: havir.g the ad.v,r.ta~es of th~ preer.t inve~tion ~
always be obtained. if the pre-polymer and. curing agent `' ,
; . . .
: ' . are selected to yield. a ~cmpound with the following . ~
,
physical properties: tensile strength-from about 1,500 , . ~ .-'
'1, to about 8,000 psi as measured.by ASTM Standard. D 412,
. .
hardness from about 40 to about 75 on the Shore d.urometer
O D scale accord.ino to ASTM Standard D 2240, elon~ation
' . from about 50% t~ about 3Q0% as measured,by ASTM Standard.
.' ~ D 412, rebound value on a Bashorè Resiliometer as
.
measured.by ASTM Standard D 2632-67, above about 17 and.
: ' preferably from about 33 to about 48,
Th~se and. other aspects o~ the present invention
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may be more fully understood wi-~h reference to the
drawing and illustrative e~amples as set out herein-
below. - .
- In the drawing is sho~m a stand.ard. golf club 10
with shaft 12 (not completely shown), club head block
14, inser~ 16 and screw attachment means 18. The
club head shaft 12 may be made of any stand.ard material
sueh as steel, aluminum, fiberglass or the new light~
weight alloys. The club head block 14 may likewise
be mad.e of any stand.ard material such as aluminum
or wood., and the preferred. club head.block is mad.e of
persi~mon wood., The plastic ïnsert 16 a~cord.ing to the
., .
present invention is mad.e Gf po'-rurethane as d.escribed. ' ~
in this specificativ~. The insert in the preferred. ,.
.. . .
embod.iment is a truncated. triangle about 1/4" thick
:~ b~t the insert may be in any shape desired., and may
cover the entire face of the club head. if d.esired..
Excellent results are obtained when tha insert is
from about 3/16" to about 7/16" thick. The insert 16
'O ~ is firmly secured to the club head block 14 by any
- means although the preferred. means comprises an adhesive
between the club head. block and. the :insert and also
screw attachment means 18 as shown in the d.rawing.
While the club head ~ace is sho~m with grooves therein,
these grooves are not essential to obtain ~he improved
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distance impar~ed by the polyurethane inserts of
the present invention. The completed. club head. may
be coated. with a finish in conventional manner.
The follo~Jing are representative exa~ples of
. polyurethane inserts made in accordance ~7ith the
present invention:
EXAMPLE 1
100 parts of Ad.iprene 315 pre-polymer was admixed.
with 14 parts of triisopropanol amine, which was the
.. curing agent. Ad.iprene 315 is DuPontis trad.emark for
: a ure~hane pre-polymer which is a product of a poly-
: tetrame.hylene ~ther glycol and. tolyl2;L2 d.iisocyanate.
The a~ount of curln~ agen-t to be ad~.ed was com~llted . ...
from the for~ula:
.
C = (Ec) (%I~
(EI)
i ~ .
, wherein:
., .
C = the parts of curing agents to be employed. .
- per 100 parts of pre-polymer;
.
!0 . ~ EI = ~he equlvalent weight of the isocyanate
. linkage~in the pre-polymer and. is 42.0; `.
%I = the percentage by weight of available
isocyanate in the pre-polymer and is 9.Z5%; ~ -
and. : .
i~ ' ' . ~ ..
; -8~
.
., ,, , , ,~ .
. . . . . . . . . . . . . .. . . . .
. ~
EC = the equivalent weight of the curing agent.
- The molecular wei~ht of triisopropanol
amine is 191.27. Since there are three
sites available for curing, the equivalent
weight of the curin~ agent is 63.76. .. A
Substituting these values in the
for~ula,
C - (63.76) (9.25) - 14 parts
. ~2 j - .
0 As sta~ed hereinbefore9 the mole ratio of the pre~ .
-~ . polymer to the curing agent is 1:1+ 20%. Therefore,
the parts of triisopropanol amine which can be add.~d.
per 100 parts of Ad.iprene 315 is about 11.2 parts to
. ~ about 16.8 parts. In the present e~ample, 14 parts
: of the curing agent were employed..
:After the pre-polymer and. the curing agent were -
: thoroughly admixed. at 250F., the product was cast to a
,- :
thickness o about 1/4". The cast p:rod.ut was then
,
press cured for 15 minutes at 230F. removed. from the
.
~'0 mold. and oven cured. for 3 hours at 230F. The cast , -
product:was then cut into the shape of an insert for
a wooden type golf club, and. the insert was shaped.
essentially as shown in the Figure. Ihe golf club
wi~h the polyurethane insert was then compared. to a , ~ .
gol~ club having a standard phenolic insert. The
:
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golf club with the phPnolic insert was the same ln alL
respects to the golf club with the polyurethane insert
except for the inserts themse'ves. In a number of
tests on a golf ball driving machine, golf balls hit
with the club having the polyurethane insert travelled.
further than golf balls hit with the same golf club
having a phenolic insert. This increased. distance .
was from 1-5 yard.s on a 250 yard. driveO
. .
~XAMPLE 2
A polyurethane insert was mad.e in accordance with
., ,
Example 1 except tha~ 11.2 parts o triisopropanol
~: amine was used. per 100 parts of ~d.iprene 315. Com- ' -
parable results were obtained.
~; ~ EXAMPLE 3
-
A polyurethane insert was mad.e in accord.ance with
Example 1 except that lfi.8 parts of triisopropanol
amine were used per lOO.parts of Ad.iprene 315. Com-
parable results were obtained......................................... ~:
EXAMPLE 4
'
!0 A polyurethane insert was made in accordance with .
. ,
Example 1 from 100 parts of Adiprene 315 and. 29.4 parts
of 3,3' dichloro 4,4' diamino diphenyl methane. When
1 0
.
.: '
~ 5~ 5 ~ ~ i
the polyurethane insert was tested. in a golf club, there
; was significant i.mprovement in yardage as compared to
a comparable club having a phenoli.c insert.
EXAMPLE 5
.. . ...
In this case 100 parts of Ad.iprene 315 wereeured with ~.85 parts of trimethylol propane
accord.ing to the method. taught in Example 1. Com-
parable results to those given in Example 1 were
obtained..
- .
!0 EXAMPLE 6
,
~- A polyurethane insert was formed from lOQ parts . ~ -
of ~d.iprene LD 355 aIld. was cured.-with 15.1 parts of
;`~ N,N,N',N' tetrakis (2-hyd.roxypropol) ethylene d.iamine
. . . according to the procedure of Example 1. Comparable
- results to those given in Example 1 were obtained.. :
: ~ ~ EXAMPLE 7
In this example a pre-polymer which is a product ~ ~.
!
of a glycol ad.ipic acid ester and. tolylene d.iisocyanate
. was used... 100 parts of the pre-poLymer was cured.with
~0 29.6 parts of 3,3' dichloro ~,4l di.amino diphenyl 1.
methane accord.ing to the method of Example 1.. When
the polyurethane insert was tested. in a golf club,
. . .
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~ ~ 5
comparable results to ~hose of Example 1 were obtained
EXAMPLE 8
A polyurethane insert was formed. from 100 parts
of the pre-polymer of Example 7 cured. with 33.1
parts of Curalon L (Uniroyal Inc.'s brand. name for
.~
a mixture of aromatic diamines) accord.ing to the
method. of Example 1. When the polyurethane insert
was compared to a phenolic insert as in Example 1, .
a significant increase in yard.age was obtained,
. , .
LO EXAMPLE 9
'~ A polyure-Lhane insert was mad.e with 100 part3
: ~ , . -.
-~ Ad.iprene 315 and 33 parts of Cur~lon Z accordin~ to
the method. of Example 1, Comparable results to those
. o~ Example 1 were obtained.
:; EXAMPLE 10
- A polyurethane insert was formed from 100 par~s
of Adiprene 315 cured. with Z7.8 p~arts of dichloro- .
benzidene according to the m.ethod of Example 1. When
' the polyurethane insert was compared. to a phenolic .
insert, a signi~icant improvement in distance was
;
obtained...................................................... i
. -12-
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1 05058U
PHYSICAL PROPERTIES - i
, ~
All of the polyurethane inserts of Examples
l-lO had physical properties within the following
limitations: -
Tensile strength from about 1,500 to about .
8,000 psi as measured by ASTM Stand.ard. D 412;
Hardness from about 40 to about 75 on theShore Durome~er D Scale accord.ing to ASTM Stand.ard.
D 2240; . -~
~` Elongation from about 50% to about 300% as
measured. by ASTM Stand.ard. D 412;
Rebound. value on a Bashore Resiliometer as
measured by ASTM Stand.ard. D 2632-67, above about .
.
It will be understood that the cl~ims are .
. intend.ed. to cover all changes and. modifications of
the preferred. embodiment of the invention, herein
chosen for the purpose of illustration, which do not
con.stitute d.epartures from the spirit and. scope of ~ i
the invention. o
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