Note: Descriptions are shown in the official language in which they were submitted.
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A~RSO RRE~r FOOl~EA~R M~ F~-A~
10 Field of the Invention
This invention relates to a liquid locking, moldable, non-swelling, polyu~lhdllefoam i~lly~g~ eA into a non-woven fabric. More particularly, it relates to a durable, liquid
abso.l~n~, non-swelling, col-~y~,ssion moldable composite mqtPriql ehat locks in fluids when
su~je~l~d to pl~S~lc.
R~~ru~d of the Invention
The problem of moisture collectin~ in shoes, boots, and other footwear has
long been a problem in the footwear art. Moi~re released by the foot, if not wicked away,
can cause discclllfoll, tt;ll~yel~llulc ~ n~es~ blisters, and fungus growth.
Typically, the moisture yl~ has been addressed by h~colyo,~ling a
mni~lre-wiC~ing liner in the footwear product. Such liners are often made from textile and
nonwoven mqttqriq1~ or a combillali~n of both.
Foam footwear insoles are well-known in the art, typically being co~ ,ised
of a ~ te conlplisi"g a liner mqfPri~l as a top layer, a foam or other cushioning mqtçri~l,
25 and a slirr~ner un-le~ the foam and liner layers. The foams are typically polyul~ e
or polyethylene foams. Current footwear insoles foams are resilient and provide a shock-
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c(~ ents of the insoles of the prior art do not provide for wicking of moisture away from
the foot and subse~luenl locking of the moisture in the insole.
The use of foams made from hyd~llilic polymers as cu~hinl ing and
absorptive insoles for footwear is one possible solution to the above problem. However,
S footwear insoles co..~ d of foams made from hyd~hilic polymers have ~ignifi(~nt
disadvq-nt-a~es. Swelling occurs upon liquid absorption in almost all polymeric foam
compositions made from hydlu~llilic polymers. In these foams, i.e., those which use a
hydlophilic polymer, absol~Jtion takes place ~n the polymer, which 11IG1~;rU1~ swells. The
swelling ~ fi~1res the thw~np~ss of the product, which is a pl~- n in the limited volume of
lO a shoe cavity. Further, c1-~n~s in f1;~ nA;~ of the foam can cause stress on the junction
of the foam with the other e1~ of the foolw~ mqtPriq1, increasing wear. Also, it would
be beneficial to have a mA-~riql which absorbs liquid only upon the qrp1irA~ n of ples~ulc;,
thus limiting absorption of moisture from, for eY-q-mp1e, a humid envii~nl"~nl when the
foolwear product is not being worn. Thus, there is a need for a liquid retqining~ co",l"~.sion
15 moldable ColllpG~ foam mqtPriql that does not swell and which absorbs moisture only upon
app1irq-tion of ~ for use as a footwear insole and/or as a shoe and boot liner.
Until the present i~venlion, there was no known polyul~lLa~le m~~eriq1 that,
when ccr t,arvted with moi~hlre~ wicks it from the surface and locks it in place upon :~rp1ir, ~i~n
of ~ SS~llc; to the mqt~riql The non-swelling absoll~"l capacity of the present invention is
20 another ~ul~lisillg and ~ ecl~ result of the novel col"~ûsilion of the present invention,
providing results superior to the al~soll~lll m~~oriqlc of the prior art.
The novel composition of the polyul~ le foam of the present invention is also
s~nrri.~ing and ~ l~t~ Methy1~nP11;p!~ -.yl diisocy~late is a non-hydl~philic prepolymer
which, when incc.l~ulated into a foam, would be eYpcted to block off access of mQi~ re to
25 any incol~ldted superal)sull~"l polymers, and would thus be e~ ;t~ to create a foam
which would not have liquid-locking capqt i1iti~s. An absol~.~l foam based on
methylenediphenyl diisocyanate which illcol~l~tes surer~bso~l~e"l polymers was not knûwn
in the art prior to the present invention, and thus its unique plu~,lies were also not
a~ aled by the art.
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Objects of the I~ on
It is one object of the present invention to provide a hy~ophilic polyurelhalle
foam that is based on the non-hydl~philic prepolymer methy1P..-Ari;~ ..yl diisocy~ulate which
S comrri~es a superabsoll,elll polymer, and which absorbs fluid upon application of p,es~u~.
It is a further object of the present ",-/e.~Loil to provide an abso,~l~l cushioning
footwear product comrri~e~ of a non-hy~philic polyulell.alle foam which, when used as in
insole or liner in a foot covering, se~ves to absorb moisture produced by the feet and thereby
keep moisture away from the feet of the wearer of the foot covering.
Another object of the invention is to provide an abs(slbe,ll, b,~
cushioning footwear product which does not absorb moisture unless p~s~ is applied to the
surface of the absoll~l~l footwearproduct, and which contin~ously releases al~so,l,ed moisture
by evaporation (i.e whether or not ~I~CS~ulc iS applied).
Summary of the I~ ~ion
The present inv~ n is a dl-rahl~, breathable, liquid abso,l~lll, liquid locking,moldable composite m~~Pri~l comrri~ing a i,ul!st~, te and a polyu,~,ll,ane foam L"~ ed into
or coated on the .s~bst~te, the polyw~ll,~le foam being made fmm a polyol, a non-
llydl~hilic prepolymer, a s~e.dbsoll~l-l polymer and one or more su~f ~t~nt~.
The co",l)osile m~tt~.ri~l can further comrri~e an acrylic polymer to impart
mcld~hility and co",~lcs.il-;lity c-h~r~ct~ri~ti~s to the m~tr.ri~l.
Detailed Description of the Invention
A~l patents and pU~ ionc cited herein are hereby il~co,~,dted by ,~f~ ce.
25 In the event of a conflict in terminology, the present ~licclosl~re is controlling.
The composite m~t~ri~l of this invention is comI)ri~ed of an open cell,
polyul~tha~e foam illlp~ P,-1 into or coated onto a woven or non-woven svl,~ e. The
polyu~el~le foam is the reaction product of a methylP~ he~yl diisocyanale prepolymer
and a polyol, s~ ~t~nt~ and optionally an acrylic polymer. The acrylic polymer, when
30 added, is added in an amount snfflcient to impart mol~ le chq~ teri~ti-~s to the foam. The
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composite mqtPrisl further col"~ises one or more superabsoll,cnl polymers that have either
been mP~hqnitqlly ~t~~hP~ to the non-woven fabric or incorporated into the polywclha,~f
foam. In a pl~f~lcd emb~imPnt, the ~u~c.dbsoll~nl polymer is incûl~ led into thepol~ulclllane; foam. The composite mqterisl can also opti~ nslly comprise a nP~AI~.J.~
S fiber finish which serves to ~i~pp~r~ce liquid to the interior of the foam and to impart surface
structure to the col~,posile mqtP.risl
The superabsoll~.d polymer-co.~ g polyulc~ e foam of the invention is
p,~ d by mixing ~ogcll~f r one (1) part of a methylP-nP~ .hf ~.yl diisocyanate prepolymer and
two (2) to six (6) parts of a polyol colllpone..ll. The polyol col~,pone.ll contains a polyether
10 polyol, surf~ctq-ntc, such as a plu~lene oxide/ethylene oxide block co~olymer such as
Pluronic k62 (about 2-15% of polyol co~ on~n~ by weight, preferably about 10% byweight), a 10% ~q~leous solution of a propylene oxide/cthyl~.~ oxide block copolymer such
as Pluronic F-88 (about 0.25-3% of polyol COIl~pOl~ by weight, plef~,dbly about 2% by
weight), one or more superabsorbent polymers (0.25-2% of polyol co",pon~"l by weight,
15 preferably about 2% by weight) and, opti~nqlly~ an acrylic polymer (.25-10% of polyol
col"~)on~,nl by weight, preferably about 3 % by weight). The acrylic polymer, when added,
provides moldability to the fin;chP11 plUdUCI.
The prepolymer and polyol co...~e~ are cr~ f~ in t_e appropriate
~lq~thies and thoroughly mixed. A plcr~l~ d method of mixing utilizes a foam m~ hinP of
20 the type well-known in the art, with a mixing head rotating at bct~oen 2500 and 4000 rpm.
The ~ lulc is dischal~ed into a ~ b~ e, preferably a carded, airlaid non-woven mqtPIiql~
w_ich has been position~d on top of a flat release nlqtPriql, such as silicQnP cûated release
paper (e.g. 92# Stay Flat k3 Liner, Terhnicote~lsiltech) Inc., ~;~ OH). The foam
is sandwiched on top by another piece of the release n~qt~riql The non-woven ~ubsl ~. 'e can
25 be a rn-q-tP.riql such as 2.5 ounce/square foot Better Blend (Carlee Corporation, 1~1rlPigh,
NJ). The papers Callylng the ~ sh~le travel ho.~lll~lly at a speed dct~ to be
s~fficient to deposit an amount of the iso~ le/polyol mixture which will yield a ~.~h
of the desired thicl~n~s~s~
The polymer is allowed to react with the polyol, yielding ca~bon dioxide and
30 a polyulc;lha~e, c, ..~.ng a foam il"pl~;n ~- 1 non-woven to form. The evolving gas is l..~
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s
in the reacting ~ ~ and form the cells of the foam. As more carbon dioxide gas is
~,e~ ~, the cells enlarge and the react. nt mass eYp ~n~l~ pluJ)Gllionately, causing the foam
to rise. At some point, the limitin~ reactant (iso~;yalldlG funrtir~nql prepolymer) is depleted
and gas gen~ on halts, typically in 4 to 6 minutes. After about siY. . -i~.- les, the top and
S bottom release papers are cQnti~ usly removed, exposing the co.~ os;le mqtP.riql The
compositP~ mqtPriq1 is then moved into a forced . ~r convection oven ~'5i~ at 220~F to
275~F in order to finish cure the mq,t~iql. ~ liti~ nql reactions occur such as chain eYtencion
and crocclinlrin~ to yield a "cured" three ~limPn~ionql network of a non-l.ydlu~Jhilic polymer
foam. When cured, the product is Iyl ;~qlly, but not limited to, from one-eighth inch to one-
10 ha1f inch in thir~nes~ After curing, the n~qtP.riql can be die cut to the desired shape andmolded. The reslllting mqt~.riql typically is capable of absu.l,ih~g from about five to about
twenty times its weight in water.
The çhemi~ql re-q-~ti- n.c oc~-u. . ;.~ during polyule~ e foam mqmlf~ lre and
contin~-o~s and discc,ll~il,uuus meth~s for such tnqn~f~~tllre are di~cussP~l more fully in
15 "Polyu,GIllalle Handbook, 2nd Edition" edited by Gunter Oertel, Hanser Pu~ chprs~ Mllnirh,
(pp. 11-244) 1993, herein i. co,~.dted by ,~,f~ ce.
A pr~r~ d isocy~lale prepolymer is Flexible Products iso.;y~ale FP 100-A
polyulGIhan~ prepolymer derived from methyle~rA;~ F-~yl liiso.iy~u~lc. A p~f~ d polyol
for use in the polyol coll.polle,~l is FP 100-B. Also pl~r~.rGd is FP 365-6 (Flexible Products,
20 M~riPtt~ GA). ~f~llcd sl~rf~ct~nt~ are Pluronic L-62 and Pluronic F-88 (BASF Corp.,
ChqrlottP, NC). A p~f~ d acrylic polymer for use in the ill~ lion is Rhoplex TR407
e.mulcion (Rohm & Haas Co, Phil~1elphi~, PA). ~fc..~d s~perqhso.l~.-l polymers are
chqrs~ct~ ,d by being able to absorb from ahout 1000 to about 5000 pe.~nl by weight of
~qu~Pous sollltion~ and to hold such fluid under pl~S~ ,S of up to about 80 psi wilh.Jul
25 d~,~. al~.~g. Such .superPqbsoll~nl polymers include croc-c-linl~p~d polyacrylate polymer, starch
grafted polyacrylate polymer, crosc-linlrP11 pop- Ccium polyacrylate/pol~,a.;lyldlllide, sodium salt
of crosclinl~P~l polyacrylic acid polyalcohol graft copolymer, partial sodium salt of crosslin~e~
polyacrylic acid, crosc-linlr~P,~l polyvinyl pyrrolidQne, crosslinked sul~natcd polystyrene,
crosclinkP~I polysulfoethyl(meth)acrylate, crosclin~d poly(2-ethylhexylacrylate), and
30 crolc.clink~ hyd~ly~d polyacryl~mitrilp. A p.~r~ ,d superabsoll~nl polymer for use in the
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mqtP.riql of the invention is AP80HS ~ abs~lbGnl polymer (Storl~h -usen, Inc., C~nsbor~"
NC).
In an embodiment in which the s1lrPr;~bso~bGlll polymer is ~co.~l.lled into the
mqtP.riq1 of the invention by mPrhqnirq1 qtt~~hmPnt, the polymer is ~PnPr~q11y qtt~~hP~ to the
S non-woven using a pl~ ul~,-3ellsilive cement or contact adhesive. The adhesive may be water
born, solvent born, or hot melt. The qmount of adhesive applied will be ~lep~ -n on the
amount of superabs~ll,enl polymer which is to be qtt ~h~7 and can be readily as~l~h~ed by
those of oldinal~l skill in the art. A non-1;-~ ;n~ G~ Jle of such an adhesive is Super 77
spray adhesive (3M Co,~.~lion, St. Paul, MN). The foam to be used in this embodiment
10 does not contain superabsoll,c~l~ polymers. This foam is p.G~ d by the same method as the
foam co.~ g supp~r~ql~soll~ ll polymers, except that water is ~ub,~;luled for the
s~1rPr.q1-sl3.l,el~l polymer in the polyol colnronPnt
The co.--l~s~ Pnq1~ of this invention can be fu~ther m~ifiP~ uti1i7ing a
nP~1P.~u.-~ h:~g process that embeds and ~un.;lu,~,s fibers of a finish mqtPriq1 into the foam
15 mqtPriq1 This ne~A1~.~u,~h;.~g process can enhqnre the ~.rGl.~ ~ rhq~~P-ri~tirs of the
product and provide the product with a finished sl~rf. ~e, which can be benPfir;q1 for ~sth~tic
as well as funrtin q1 reasons. When present, a fiber finish mqtPriq1 can aid in passing fluids
to be absorbed into the und~.ly,ng foam matrix. The fibers of the finish can be either
hy~l)hilic or hyd~phobic, and serve to guide or draw fluids into the foam matrix leaving
20 a soft, dry surface. Non1;-..;~ ~llp'es of fibers which can be used in this finish of the
present invention are acrylic, polyI,lop~lene, or polyester fibers, or a blend of these.
Example
A polyul~ G foam was pl~l)~d by mixing tc.~ er one (l) part of an
25 isocyanate FP lO0-A prepolymer and four (4) parts of a polyol co..~ r-~ The polyol
con~ollcnl colll~lised polyol FP lO0-B, Pluronic Lr62 (10% by weight), a 10% aqueous
solution of Pluronic F-88 (2% by weight), Rhoplex TR 407 (3% by weight) and
super~l soll~llt polymer AP80HS (2% by weight). The two colllpon~.~ were brought~gethPr in a mixing head at about 4000 rpm. The lllh~lul~ was allowed to discl~e into a
30 carded, airlaid non-woven on top of a ~i1iconP coated release paper and sandwiched on top
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by another silicone coated release paper. The papers traveled hol~nl~lly at 4 feet per
minute, yielding a thir~n-Pss of one-quarter inch in the product.
During the next four to six mim~tes~ the polymer reacted with the polyol
causing a foam ul~pl~nated non-woven to form. After six ...i...~es the top and bottom
S release papers were cc-ntin--ou~ly removed from the top surface, C;A~)OSmg the mqtPri~l. The
product was then carried by a moving belt into a forced air convection oven m5;..1;. IrA at
220~F for the ~u,~ose of finish curing. The res~lting m~Priql was an open cell foam,
A non-woven, white in color, one-quarter inch thick, that was wettable when
was applied to the surface in contact with moisture.
