CA2062088A1

CA2062088A1 - Game ball

Info

Publication number: CA2062088A1
Application number: CA002062088A
Authority: CA
Inventors: Donald E. Williams
Original assignee: Donald E. Williams; Wilson Sproting Goods Co.
Current assignee: Wilson Sporting Goods Co
Priority date: 1991-03-01
Filing date: 1992-02-28
Publication date: 1992-09-02
Also published as: CN1065600A; US5123659A

Abstract

GAME BALL

Abstract of the Disclosure A game ball is made by rotationally molding a hollow spherical core from a blend of foamed Surlyn ionomer resins and low density polyethylene resin. The center of the hollow spherical core may be filled with foamed polyurethane, and the spherical core may be covered by a leather cover. If desired, hollow ceramic microspheres or beads can be added to the resins before molding.

Description

~aclcqround 2 0 6 2 0 8 8 This invention relates to ga~o balls, and, more particularly, to a ga~e ball with a spherical core formed from a blend of a foamed mixture of ionomer resins and low density polyethylene.
This invention i~ an improvem~nt over the game balls described ln my prior U.S. Patent No. 4,861,028. As described in my prior patent, soft balls have hlstorically been made by forming a spherical core of cork, kapok, or slmilar material which is bound together. A layer o~ windings o~ string or yarn is wrapped ovor tho core and a loather cover i8 placed over the windings and stitched toqether.
In recent years, game ball~, particulnrly softballs, have been made from moldRd plast~c cores. For example, U.s.
Patent No. 4,149,720 describes a ball which includea a foamed polyurethane core and a leather cover. u.s. Patent No .
4,364,565 descrlbos A ball uhich i~ludeD a spherical core made from foamed nthylnno vinyl acetate copolymer and Surlyn, an ionic copolymer which i9 available rrOm E. I . DuPont de Ne~ours and co. (DuPont~. U.S. Patent No. 4,6~0,071 describes a ball whlch lnc~udos a coro whlch i9 molded rro~ Nucrol (ethylone acid copolymor~ and rilled with polyurothan-. A cover is sown over the core. U.8. p~tQnt N0. 3~069~170 descrlbQs a ball Which lncludes ~ core Of ~oamod polyethylene and a Cover. U.S. Patont No. 4,463,951 descrlceu a ball Whlch 1~ made by rotatlonally moldlng an outer lay~r Or foamed polyvlnyl chlorlde and ln~octlng polyurothane ~oam lnto the cavlty.
The ~ollowlng United state~ pAtents descrlbn balls whlch aro ~ormad rrom 8urlyn: 4,572,507, 4,529,200, 4,56a, oa~, and 4,C53,752.
Speci~ic~tlon~ for 30rtballs havo b~en l~aued by t~o gov~rnlng organizations, the United Stateg Slow-pitch Softball Assoclation (USSSA) and the A~ateur Sortball Assoclatlon (ASA).
The speciflcations of tho USSSA ~n effect before 1989 permitted 11 and 12 inch ~ortballs to have a coer~icient of restitution (COR) ranglng from 0.44 or under to 0.52, dependlng upon the category or class in which the ball was used. Different categories would be indicated for example, by the color o~ the stitching on the CoVer. Beglnning in 19~9 the COR of USSSA
licensed balls could not exceed 0.50.
Coefficient of re~titution (COR) i8 one measure of the livelineos of the ball. COR is measursd by propelling a ball against a hard sur~ace at 60 mph (88 fp~) and measuring the rebound speed of the ball. COR is expressed ln terms o~ the ratio oi' the rebound speed to 60 mph (88 fps).
Other qualities oi softballs aro important whlch are not included in the ~oregoing "official" speci~ications. ThesQ
qualitles lnclude the sound of the ball when batted, texture of the ball, the "feel off the bat" or, the feel which the batter experience~ at the moment o~ impact, rlight distance and consistency, and durabllity.
My prlor PAt-nt No. 4,861,028 de~cribes a ~o~tball which includec a hollow core which ls ~ormed by rotation~lly molding low density polyethylene or ~ mixture Or low density polyethyl-no ~nd An ethylene acld copolymer. The speciric ethylen- ~cid copolymer descrlbed iN av~ bl- rrOm DuPont under the name Nucrel. ~ho low density polyethylene used 19 sold by the USI Divi~lon or Quaneum Chemic~l Corporatlon undor the designatlon Mlcrothen- MN718 and har a donolty Or 0.915 grams/cc and a ~l-xural moduluo Or 20.6 kpal ~lOOO poundo per oquaro inch). Thd oo~tballs rormod in accordance wlth my prior patent have not been woll recelved. Thooe oortballo dld not Carry as well ao oolld core balls, and the hollow balls had a tendency to fracture whon played ln temperAturQs bolow 40' F.

= a~y ot tho Invention I have ~ound that rotationally molding a blend of two dl~forent Surlyns (lonomer resins available from DuPont) substantially improves the performance of the core. The corecan be ~urther improved by adding a minor a~ount o~ low density polyethylene (LDPE), e.g., ~rom 15 to 30% by weight, and a chemical blowing agent ~Ci3A). The LDPE preerably haA a density within the range o~ about 0.910 to 0.940 gm/cc. The LDPE serves as a compounding grinding agent and reduces the cost of an all-9urlyn core. The blowing agent SormE~ a foamed core, and the thic3cness of the core wall i5 sub~tantially greater than the thickness of the unfoamed cor~, thereby decrea!3ing the size of the hollow interior. The foamed core also has greater resistance to deformation and plays and ~eals more like a solid core. The amounts o~ the 9urlyn, the low density polyethylene, and the blowing agent can be varied as desired to vary the COP~
and the compression re~istance (~eel). The COR can be lowered and compression re~i~tance can be improved by adding hollow ceramic micro5pheres. The hollow core can be filled with foamed polyurethane if deslred.

~scriptlon o~ the 12rawlnq Tho lnv-ntion wlll be explalned ln con~unction with illu~tratlve embodimHnts shown ln the accompanying drawings, in which Fl9. 1 lllustrates a softb~ ormed in accordanca with the inven'clon~
Flg. 2 lg a 8~ctlon~1 VlQW 0~ th- 80rtb~lll tormed With a hollow spherlaal cor~J
Flg. 3 19 a Dectlonal view ol a 80ttball formed ~rom a spherlcal cora whlah lg ~llled With polyureth~lne rOam~
Flg. 4 19 a graph showlng thQ COR ol! hollow aores using varylng amount~ or Surlyn 8528 and Surlyn 9450 and 15% by weight low denslty polyethyleneJ
Flg. 5 1l3 a graph showlng tha compresslon resistance oE
hollow cores uslng varying amounts o~ Surlyn 852~ and 9450:

, . 2062088 Flg. 6 i~ a graph showing the COR of hollow coras uslng varying amounts o~ ceramic microspheress Flg. 7 19 a graph ~howlng the effect of the amount of chemical blowing agent on the wall thlckness of the core Flg. a is a graph showing the e~rect of the amount of blowing agent on the COR of the core:
Fig. 9 is a graph 3howing the errect Or the amount of blowing agent on the deformation o~ the core;
Fig. lQ is a graph showing the erfect Or the amount of blowing agent on the Shore D hardness o~ the core:
Fig. 11 iB a graph showing the e~ect of the amount o~
blowing agent on the lnltlal veloclty ol the core.

Descrl~tion of S~eci~lc Embodlment~
~ he lnventlon wlll be explalned ln con~unctlon with a so~tball 15. The partlcular softball lllustrated in the drawlngs i9 a 12 inch clrcumference softball, but lt wlll be understood that the lnventlon can be uoed wlth other sizes of balls, for examplo, 9 ~nd ll inch clrcumf-rence balls, and with other gamo ballo with and without cover-.
The so~tball 15 includes a hollow spherical core 16 and a cover 17 which surrounds the core. The covor is formed from two dumbb~ shaped piece~ 18 and 19 which are stltched or ~ewn togother along senms Z0. The cover c~n b- rormed rrom leather, vlnyl, or simllar mat-rlal which can b- uD-d to slmulate the look and ~sel Or leath-r cover~. For a lZ lnch ortball the out~lde di~met-r o~ tho cor- 18 wlthln th- rang- of 3.66 to ~.70 lnch-~, and th- cover thlcknes- lo about 0.05 to 0.06 lnch. The wall thlckn-oD o~ the core can bo wlthln tho range of about 0.~6 to 0.5C lnch.
The core 16 ls formnd ~rom a blend Or foamed resins, namely two dlfferent Surlyns ~lonomer reclns available from DuPont) and low denslty polyethylene resln. The preferred 2062~88 procedure for forming the cors is rotatlonal molding.Rotational molding is a well known art, and a detailed description of the procedure is unnece~sary. ~he plastic resins are introduced into a mold, and the mold is rotated biaxially in a heated cbamber. Th8 mold is rotatably mounted on a spindle, and the mold is rotated by the spindle while the spindle i9 rotated about an axis which is perpendicular to the axis of the spindle, In rotational molding, there are e~entially four basic steps: loadlng, molding or curing, cooling and unloading. In the loading ~tep, either liquid or powdered polymer material is charged into a hollow mold. The mold halve~ are then closed and moved lnto an oven where the loadad mold spins biaxially.
Rotation speeds should be variable nt the heating station.
In the oven, the heat penetratea the mold, causing the polymer material, if lt 19 in powder form, to melt and conform to the mold surface, or if it is in liquid form, to start to gel. Tho heating is usually accomplished by air or by a llquid of a high specific heat, 9uch as molten salt or where ~acketed molds aro u~ed, by a llquid medium such as oil.
A- tho molde Are heated in the ovon, th~y continue to rotate so t~at tho polymor matorial wlll gr~dunlly become dl~tributed evenly on the molded cavlty through centrifugal force. As the heatlng continues, tho polymor materlal melts completely form~ng a homogeneous layor of molten plastic.
When tho partD have been formod, the molde are tran9ferr~d to a cooling chamber where coollng la accompli~hed by any moan~, preferably cold water spray or forced cold alr.
During cooling, tho mold contlnues to rotat- so thnt there are no distortions formed in the ur~aCe of the molded product.
Lastly, the molds are opened and tho parts removed either by manunl or mechanical means.
In forming game ball~ In accordance with the preferred embodiment of the lnventlon, the mold is loaded with a blend o~

20~2088 Surlyns, low density polyethylene (LDPE) resln, and a blowingagant It i8 believed that Surlyn has not heretofore been rotomolded becau~e Surlyn resin is not readily available in powder rOrm and cannot be alr ground The LDPE serves as a compounding/grinding aid and al~o reduce~ the cost of an all-Surlyn ball The LDPE i5 extruslon blended wlth the Surlyns, and the blend 15 ground into a powder The preferred ball used 17~ by weight Surlyn 8528 ~rom DuPont, 6a% by weight Surlyn 9450 from DuPont, and 15~ NA 117 LDPE in pellet Porm from the USI Division Or Quantum Chamical Corporation, Tha comparable powder form Or LDPE is MN-718 The chemical blowing agent (C~A) i~ a modlrled azodlcarbonamide available from Unlroyal Chemical Company under the designation Celogen AZ 2990 The amount or the blowing agent ls pre~erably in the range Or 0 35 to 0 50 parts per hundred ot the total of Surlyn and LDPE resin~ The blowinq agent expands the wall thickneos o~ the core and makes the ball play and ~eel more like a solid ball As wlll be explalned herelnafter, the COR and compreeslon resist~nco of the core can be varled by changlng the ratlo o~ 8urlyn 8526 to Surlyn 94SO Tho core c~n be further improv-d by addlng beads or mlcro~phero- to the r-Dlne ln an nmount Or up to 10% o~ the totnl welght o~ th- cor- Thn preLerred mlcrosph-re~ are AvallAble rrom ZoolAn Industrles Oe St Pnul~ Mlnnesota under tbe deslgnAtlon Z-Llght W-lOOO . ~he microDphorus are hollow Yillca-alumlna corAmlc nlloy ~phoros havlng a dlnmeter or lo to 150 mlcrons~ A gpeclrlc gr~vlty o~
0.7 to 0.9 q/cc, a hardno-~ o~ MohD 8cal- 5~ und a ccmpressive 9trQngth Or 5000 p~i The mlcro6phere~ increase the wall thlcl~nesEI at the core, lowqr th- CoR and I.V. (lnltlal velocity), lncrea~e hardne~s ~llghtly, and reduce the de~ormatlon (compreeelon resl~tance) under a 400 pound load, espQclally at 100 degrees 20~2088 Fig. 3 illustrates another 12 inch circum~erence softball 22 which includei a ~pherical core 24 formed in the same way as the core 16 and a cover 25. The center of the molded core i3 fllled with low density polyurethane foam 26.
The PU foam makes a three-piece ball -- the core, the cover, and the PU center -- and m~kes th~ ball play and ~el moro ~ike a so~id ball. The PU ~oam al60 preYents rattles i~ small pieces of the core break o~f during repeated impact~. The particular PU used is SWD-760-2, a two-part liquid polyurethane sold by SWD
Urethane Co. of Mesa, Arizona. The molded core i provided wlth a suitable opening for introduclng the m~xed polyurethane components, which foam ln place inside the COrQ.
Surlyn res1ns are ionic copolymers which are the sodium or zinc salts o~ the reaction product of an ole~in having from 2 to 8 carbon atoms and an unsaturated monocarboxylic acid having ~rom 3 to 8 carbon atom~. The carboxylic acid groups of the copolymer may be totally or partially neutralized. Surlyn resins and the method o~ producing Surlyn resins are explained in detail in Ree- U.S. Pat~nt No. 3,264,272.

Surlyn ~52a i3 a sodlu~ Surlyn and has the phy~ical propertleo ~et forth ln Table I. Surlyn 9450 i9 a 2inc Surlyn and has tho phy8ical propertiea gat forth in Table II.

Denslty - g/cc: .94 ASTM D 792 Melt Index - dg/mln: 1.3 ASTM D 1238 Ten~lle - KPSI: 1.8 ASTM:D 638 Elongntion - ~: 450 ASTM D 638 Flex Modulu~ - KPSI: 32 ASTM D 790 Hardnes8 - Shor- D:60 ASTM D 2240 Vlcat Sortenlng - Deg. C: 73 ASI~M D 1525 All of the above values are nominal: Measured value9 should be withln 10~ or the nominal values.
Note: Melt index i5 highly influenced by moisture content and should be run on a sample ~rom an unopened bag.

~Ub~

TABLE II
Density - g/cc: .94 hSTM D 792 Melt Index - dg/min: 5.5 ASTM D 1238 Tensile - KPSI: 1.2 ASTM D 638 Elongation - %: 500 ASTM D 638 F1RX Modulus - KPSI: 19 ASTM D 790 Hardness - Shore D: 54 ASTM D 2240 Vicat Softening - Deg. C: 79 ASTM D 1525 All of the above ~alues are nominal~ Measured value~
should bB Withi~ 10% o~ the nominal values.
Not~: Melt index is hlghly ~n~lu~nced by moisture content and ~hould be run on a sa~ple from an unopened bag.
Low denslty polyethylene sold under the designation NA
117 has thQ physlcal propertleg set ~orth in Tabe III.

TABLE III
Denslty - g/cc: .915 ASTM D 792 Melt Index - dg/mln: 8 ASTM D 1238 Tensile - KP5I: 1.7 ASTM D 638 Elongatlon - ts 525 ASTM D 638 Flex Modulu- - KPSI 20. 6 ASTM D 790 Hardnesl~ Shore D: 48 ASTM D 2240 Vicat Sortoning - Deg. C: 88 ASTM D 1525 All the above values are nomlnal: Moasured values should be within lo~ ot the nominal ~Alues.
one blend o~ roslng used to make aortballs ln accordance wlth th- lnv~ntlon UB~d 17t by walght of 9urlyn 852~, 68~ by wlalght Or Surlyn 9450, and 15~s by welght Or LDPE. This blend la called Blend X. Twelve lnch ortballs made from foamed Blend X core~ were comparsd wlth commerclal softballs sold under the names Red Dot ~nd Thunder. The results are set forth in Table IV.

D~or~ lon C~rry ~oo lb--. ~ V Dl--C~nc--~lghe 912- COR (lncl~ ) (t-~t/~
lg~L 1~ ~IQ:~ ~t ~0-~ t ~0-~
~l~nd X 197.9 12.01 0.5~.7 0.2~6 0.~72 1~7.~ 3~ 3~
R~l Xt. 179.6 11.~7 0.1~2 0.2~. 0.27~ 1~6.~ O
rhund-r1~0.3 11.91 0.~01 C.~ 0.~0~ 1~7.'~ 3-7 ~5 Figuro 4 ~hows th~ ~foct o~ ~rylng th~ p~rcnntages of Surlyn 8s2a and Surlyn 9450 on tho co~ Or th- cor- All core~
had a total Surlyn content o~ as% by wolght o~ tho total resin welght and 15~ by woight LDpR. Tha d~t~ indlc~ted by & eqy~re i9 for cor~ whlch also lncluded o S pph blowing agsnt Tbe dat~ lndlc~ted by an + i~ for cor~o which lncluded 0 4 pph re~in blowing agqnt and 10% by welght Or th- core o~f Z-Light c-ramic bead- or mlcrophore~
Flgur- 5 showe tho effoct o~ varylng th- amountg of Surlyn 852~ and Surlyn 9450 on tho compreselon reel~tance of the cor- All cor-e had a total Surlyn content o~ 8S% by weight of the total ro~ln w-lght and 15~ by wolght LDPE Th~ core~ were made with and wlthout cera~ic b-aaa aa indlcatod Th- amount of bead- lu lndlcate~ ~e p-rcnt by w-lght Or th- total w-lght or the cor~ lncludlng tho b-8d-Y~gur~ 6 ohowo th- o~t-Ct ot th- amount Or c-r~mic be~d- on th- COR o~ tho Coro Tho coro~ w-r- ~d- ~rom 810nd x wlth 0.5 ppH blowing ag~nt.
Flgur-x 7 through 11 ~how th~ -ct o~ tho amount o~
blowlng ag-nt on varlou- prop-rtloo o~ th- cor- W~th 0, 5, and 10~ by w-ight o~ c-ramlc b-adr Tablo V ia a matrlx whlch nhowo th- ~roct o~ varylng amount~ or blowing ag-nt and Z Llght caraulc b-ad~ on the phyDlcal prop-rtl-o o~ core~ o~d- fro~ ~l-nd X

2062~88 8 Llght Lav-)_ Blo~lnq Aal~ne ~v~l PPH 0 0 . 2 0 . 4 0 . 6 ot ~-lght ~ . 152.3 150.6 151 149.4 Slz~- ln. clrc. 11.51 1l.~ 9 ~all ehlc~n-,- - lnchU.2590.3370.395 0.36 D ~OL~ ~400 lb.
e80 d-g - lnch0.3890.3550.3~30.3~1 ~loo d--~7 -- lnch0.619 0.3G1 0.5~1 0.469 ~horr D ~rdn~a- 50 ~ 30 26 C.O.R. C~0 ~P80.55g0.3460.~390.539 I.V. ~.4 turnn - FP~31'18.9 14~1.1 1~7.1~ 1'18.7 ~- ~ lghe - g~. 152.9 1~.l 150.9 150.3 ~312- - ln. clrc. 1l.~ l 11.5 11.~9 lc~n~ lnch0.29~0.3~ 0.39~ 0.3a2 D~or~ ~400 lb.
~ao i.q - lnch 0.3120.29~ 0.~62 0.268 9100 d-9 - nch .~ .496.451 .421 shor- D H-rdn-~ 52 3~.~ 31-5 27.5 C.O.R. caa P~80.53a0.5390.5a70.~3 ~ a.4 turno - rP8 - - 1~5.7 ~.4 lOt l~clqht - gu... 151.~ 150.~ 1~9.3 1~7.1~
81~- - ln. clrc. 11.51 11.~ 9 11.8~
~nll thlc~n--- - lnch 0.~69 n.3~ 0.~7~ 0.~32 D toro. t400 lb.
~o dog - lnc~ 0.27~ 0.~ 0.~9 0.2~1 ~loo d~9 - lnch 0.473 0.4340.419 0.~93 shOr- ~ H-rdn~ 0 ~ Z9 C.O.~ 811 ~P~I 0.~ 0.~2~0.~2 0.51~
I.V. 9~.4 turn~ g 147.314~.-146.1 145.0 Phy31cAl prop-rtle~ or nottballs made from cores o~ two addltlonal blend- aro s-t rorth ln Tnbl- VI. ~l-nd X .4/10 was Blend X wlth 0.~ pph blowln~ agont and 10% Z Light beads. ~lend 10.10 was 10% surlyn ~8, 75~ Surlyn 9150, 15% ~DPE, 0.4 pph blowing ~g~nt, and 10~ Z-~lght beada.

TA~ V~
D-toreatlon carry ~-lgbt 61~- COR ~nche-) ~ta-t/oeo.) DI~C nc-J~lg~L~D9h9--~, ~IQ~ 10 ~ ~ ~g c 4 ao~ ~ 9 0 ' ~ O18~.71~.9 0.~07 0.~59 o.~ .6 3~
10.~.0 11~9.71~,.91,0.49:1 0.3~ 0.~7~ 40 Tabl~ VII comparos co~m-rclal Thund-r and Rod Dot so~tball~ with ~ortball- rorm~d ln accordanc- with the $nvention uslng 15, 20, 23, and 25% LDP~ and varylng amounts Or Surlyn.
The Thunder, Red Dot, and 81and X ball~ ln Tablo VII are not the same balls whlch w-re tested In Table IV. The ball~ ln Table VII were not tested tor carry dlstance.

206'~08~

T~L

Delror~ t~on e ~oo lb-. I V.
~t~lgh~ sl~- (lncl~ COQ (~-e~c.) lg~l (inch-~.L at 30'F ~Q~! ~t ao ~ ~t 00'F .
hund-r 170.2 ll.a9 0.3~0 0.4~0 0.~94 139.1 R-d Dot 180.9 11.~1 O.a~l 0.30~ 0.i71 1~5.~
~l~nd X 1~7 ~ 12 01 o 29~ 0 ~60 o.~ 9.3 ~00 1~7.~ 1~.87 0.297 o.~s 0.~611 134.0 ~1~ 190.9 11.91 0.160 0.411 0.~93 135.6 215 1~7.0 11.1~11 0.255 0.~12 0.~9~ 1~6.0 Elloml ~0~ l~nd 21~~,pn~l ~1!1 8urlyn . O~
9~0 ~0 65 ~0 L~Plt ~0 ~3 ~
C8AO . ~ N o . ~ PPNo . ~ PPH
8ph-~--- 9 9 Although I hav- tound that a bl-nd o~ Surlyn 8528 and 5urlyn 9450 produe-o uuporlor re~ulto, lt 1~ pooolbln that other 5urlyno could provld- comparabl- r-~ulte Uslng two dl~rersnt Surlyno allow- tor varylng e-rtaln phy-leal proportlco o~ the ball a~ d--lr-d by varylng th- ratlo o~ th- 8urlyn-Tho eoramle b-a ~ r-due- th- eompr--alon re~l~tAnce under A 400 pound load~ op-alally At 100'~. It lo b~ ved that eompr-~elon r~ tAno- is rolat-d to what play-ro descrlbe ao ~It-ol " A mor- eompro--lbl- ball ~-al- h-avy and 1- not p-re-iv-d ao llv-ly A l--- compr---lblo ball t--l- llqht and "~ump-" Ort th- bat Whll- ln th~ tor-golng ~p-cllleatlon d-tallod d-serlptlonn ot p-cl~lc ~mbodlm-nt- ot th- lnv-ntlon w-re set ~orth rOr th- purpo-o o~ lllu~trAtlon, lt wlll b- understand that many Or th- d-tallo her-ln glv-n may b- varl-d conslderab1 by thos- sklll~d ln th- art ~Ithout d-pArtlng rrOm th- spirit and scop- o~ th- Lnv-ntlon

Claims

1. A molded plastic game ball comprising a spherical core formed from a mixture of an ionomer and low density polyethylene.

2. The game ball of claim 1 in which said core is rotationally molded.

3. The game ball of claim 1 in which said core includes a blend of two different ionomers.

4. The game ball of claim 3 in which said core is foamed.

5. The game ball of claim 1 in which said core is foamed.

6. The game ball of claim 1 in which said core includes about 0.35 to 0.50 parts for hundred of blowing agent

7. The game ball of claim 1 in which the interior of the core is filled with foamed polyurethane.

8. The game ball of claim 1 including a cover on the outside of the core.

9. The game ball of claim 1 in which said core includes about 10% by weight of beads having a diameter of about

10 to 150 microne.
10. The game ball of claim 1 in which said core includes about 70% to 85% by weight of ionomer and about 30% to about 15% by weight of low density polyethylene.

11. The game ball of claim 10 in which said core includes about 0.35 to 0.50 parts per hundred of blowing agent

12. The game ball of claim 10 in which the interior of the core is filled with foamed polyurethane.

13. The game ball of claim 10 including a cover on the outside of the core.

14. A molded plastic game ball comprising a spherical core formed from:
a) a first ionomer;

b) a second ionomer;
c) low density polyethylene.

15. The game ball of claim 14 in which said core includes about 0.35 to 0.50 parts per hundred of blowing agent.

16. The game ball of claim 14 in which the interior of the core is filled with foamed polyurethane.

17. The game ball of claim 14 including a cover on the outside of the core.

18. The game ball of claim 14 in which said core includes about 10% by weight of beads having a diameter of about 10 to 150 microns.

19. The game ball of claim 14 in which the amount of the first ionomer is about 10% to 17% by weight, the amount of the second ionomer is about 75% to 68% by weight, and the amount of the low density polyethylene is about 15% by weight.

20. The game ball of claim 19 in which said core include beads having A diameter of about 10 to about 150 microns in an amount of about 10% by weight or the total amount of ionomer and low density polyethylene.

21. A method of making a game ball comprising the steps of:
mixing an ionomer resin and low density polyethylene resin to form a blended resin;
introducing the blended resin into a rotational mold;
and rotationally molding a hollow spherical core.

22. The method of claim 21 including the step of grinding the blended resin into a powder before introducing the blended resin into the rotational mold.

23. The method of claim 21 including the step of mixing a second ionomer resin to form the blended resin.

24. The method of claim 23 in which the amount of the first ionomer is about 10% to 17% by weight, the amount of the second ionomer is about 75% to 68% by weight, and the amount of the low density polyethylene is about 15% by weight.

25. The method of claim 21 including the step of mixing a blowing agent with the blended resin before the blended resin is introduced into the rotational mold and allowing the blended resin to foam during rotational molding.

26. The method of claim 21 including the step of mixing beads having a diameter of about 10 to 150 microns with the blended resin before introducing the blended resin into the rotational mold.

27. The method of claim 21 including filling the hollow interior of the core with polyurethane foam.

28. A method of making a game ball comprising the steps of:
a) mixing a first ionomer resin, a second ionomer resin, and low density polyethylene resin to form a blended resin:
b) grinding the blended resin into a powder:
c) mixing a blowing agent with the resin d) introducing the resin and the blowing agent in which the amount of the first ionomer is about 10% to 17% by weight, to amount of the second ionomer is about 75% to 68% by weight, and the amount of the low density polyethylene is about 15% by weight; and e) rotationally molding the resin and allowing the resin to foam to form a hollow spherical core.

29. The method of claim 28 including the step of mixing beads having a diameter of about 10 to 150 microns with the powdered resin before introducing the resin into the rotational mold.

30. The method of claim 28 in which the amount of the first ionomer is about 10% to 17% by weight, the amount of the second ionomer is about 75% to 68% by weight, and the amount of the low density polyethylene 18 about 15% by weight.

31. The method of claim 23 including introducing a two-part polyurethane into the interior of the core and allowing the polyurethane to foam.