Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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rha p~ant ln~ent~Dn r~lat~s to ~mprov~en~s ~n ~ndlor r~1ating to
multllayer.he~t shrin~able pl~stic fll~s, Gontainers (~ bags) o~ packag~s
using same and to re7ated medns dnd meth~ds.
M~ dyer heat ihrlnkable ~ilrns ha~ been u~ed ~or some time f~r the
shrink wrapp~ng of vQrlous food products including Mo~t p~oducts whl~h ~ill
r~quire refr~ dtlon or frr~e2in~. ~e~rdb1~ chdrac~ar~s~lcs ~n such ~ s ~r~
their de~ree o~ shrinkd~ un~er ~odera~ h~t an~ th~lr r~sls~ance to ab~se.
~ urr~ntly ~/a~lable ~n New ~ala~d arQ sever21 ~ilm~ useflll In the
~rapp~ng of prnducts sufh A~ m~at~. Th~s~ include lon4m~r bas~d m~t~riAli,
dmptoyad in iono~n ~d9S of tr;gorl Packa~;ng Syst~n~s ~lt) L;~lt~d df Cornar
A~ n ~r;v~ ~nd ~or~man Ro~, Hamilton, N~w Zoal~nd ond th~ EYA
~ethylene-vlny~ acetqte copolymor~ ba~ed ~at~rlAl~ of W~ Gr~ce (Pl23 ~;mited of
~rosse~ ~tr~ot~ Elsdon, Poriru~, ~hlch ~re kn~m as the~r SL3 and S~ bags.
~ h~ abu~e resi~t~nce ~ the tllm~ it ~m~rQ~d would make 3uch conta1n~
~ore useful ~n the pa~ka~ns ~ product~ havln~ a yreat~r t~n~nry ~4 penetr~
or puncture th~ packa~ln~, su~h as ~eat cuts ln whtch ~ones are ret~lned. It
ls also des~ra~le for ~lms to have ~ood re;ls~nce t~ external abuse.
It is also des;r1~le f~r such ~ lms t~ h~ ~high shrink~ as th
lmportant w;th respect tç both pr~s~ntation and çon5u~er appeal.
In this re~ard, Nçw 7ealfln~ P~t~nt ~p~liCAtiQn ~o. ~6 ~3 ~ r~c.e
~N2~ Ll~lted reldte~ ta multilayer fllms hQY;nJ both ~od r~sist~nc~ t~ a~us~
~nd heat shr1nk~b~ y. These fil~s cD~prise at least three l~yers; two
outs1de lay~rs, e~ch co~prlsln~ ~LDPE (very ~w dens1ty polyethylen~) ~r a
bt~nd of ~LD~E~VA, an~ ~n ~nt~nal layc~ w~1ch 1~ EVA r~r pr1m~rlly EVA,
S~E ~:lg8Z~081 -8S~ZL~ Z -~ ' NOS ~ r ~ 35
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Thc pre~ent 1nvcnticn is dir~t~d t~ fil~n~, contaln~rc, p~ck~g~ and
method~ Or prDducln~ f;ln~s, ~hl~h ~ill go som~ way towar~ m~etln~, ~t 1e~t ln
p~rt, the ~bovo ~ntion~d a~ms o~ ~ood abusq r~ol~tanco and he~t shr1n~bll1ty
by different ~e~ns, or at l~ast pr~id~ th~ p~llC with ~ u~eful cholr-~.
~ used hercin, the term UVLDPE" r~fers to v~ry low d~nslty polyethy7en~
"~YA" r~ers to Dn ~thylen~vlnyl ~cet~ opYl~ne~ E~AA~ r~f~rs ~ ethyl~n~
meth~rryllc acid c~p~lymer, ~EAAI' to ethyl~ne ~cryllc aeld eopoly~er, "PVDC" tov~nyltdene ~hl~rld~t~ln~t chIoride cop~lymer, ~nd "~I~" to ~lnyllden~ chlorlde
met~y~ acrylate cop~1ymer.
Accordl~gly, In a ~lrst aspec~ the presen~ lnYen~1~n m~y br~dly ~æ ~a~d
to comprtse a he~t-shrlnkabl~ multl1ayer ~ h~ g a m~asure o~ resistdnc~ to
abu~, comprlstn~ at le~3t th~e~ layers, lnclud~ng~
a) a flrst ol~t~ide ldyer sele~ed fr~n th~ group ~:u~prisiny EVA, VLDPE and
blRn~J.s ~f YLDPE and EYA,
b) a core or lnternal l~yer, c~mpr~s~ng an ;qnomer or a blen~ ~h~r~n~ wlt~
EYA, ~ or EAA, and
G) d iiccnd ~tsid~ l~yer se1ec~ed frorn the ol^oup co~prl~tng EMAA, EAA ~n~
~ nno~rs .
the core or lnternal l~y~r b~ pr~ferably compl~;s~ o~th~r
1~ sc~1um lono~or p~ly~r ~lone, ~r
10nd of ~od;u~ lon~n1er p~lYrne~ w~th EYA, comp~ n~ up to a~o~t
4091 EYA, or
Z~S081 ~ 6Z~ ~b~ Z -~: IYOS ~ r ~:~a l,~S
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~) 3 b1end o~ sod~l~m l~nomer p~lyn~r w~th E~AA or EAA, co~prisln~ up to
about 25~ of tne ~A~ or ~AA-
F~r ex~mpl~, a b1end ot ~bot~t ~3$ s~dlunl ion~er p~ or (~ecl~lc gr~vlty0,9~ ~1th a~out 7~ ~YA ~spe~lflc ~rA~l~y 0.96), or d bl~nd ~f dbout 95~ sodlum
lon~mer po1ymer wlth ab~ut 5% EMAA ~r EAA ~Pecific ~r~Yi~y O.g4~ ~ay ~ us~d,
Th~ flr~t outsld~ layer a) whtch 1s pre~era~ly the ~ut~r o~use l~y~r,
pr~f~rably comprt~s ~lther EVA ~lone or a ~lend o~ VL~P~tEYA ccrprl~tno fro~
abcu~ Ok ~ 70~ EVA, Qg a blond ~f 50~ EVA ~speelfl~ ~rav~ty ~.g~ YL~PE
~pec;f;~ gr~vity O.~l).
The second outslde l~rer c~, i5 proforahly ~ lin~ lay~r, ~hlch ln u~e
w~ ont~ct A prqduct ~0 be pack~g~ by t~s fllm, ind co~p~iS~ ~1ther EMAA,
EAA or sodium l~nolner polylner,
~ h~ f11ms o~ the pres~nt inYenti~n m~y ~l~o ~lnprl~e ~n ~y~en b~rrlar
layer, ~uch as l/lnytld~n~ chlorl~ nyl chl~r~de ~polymer, vinylld~ne
chlor~de meth~yl acrylate cnpolymer, ethylene v~nyl alc~hol copo~ym~r or
p~lya~ide, located ~Qt~een the ~1rst outslde l~yer a) ~nd the lnt~-n~) layer
b~. In addlticn, poly~erlc adheslYe layers ~eg ~MAA) ~ay ~e lne~lId~d, b~t~een
the rirst Qutside layer nnd ~h~ lnt~rndl l~y~r, or, l~ a barrl~r layer li
included, ketween ~he barrier 1ayen and the first ou~s1~e tayer an~tor b~tween
the barrier layer and th~ internal layer h).
In ~ ~urther aspcct the pres~nt ln~eneion co~prises a multllayer f~l~
ha~ting ~ ~Qa~urs of res~!;tanc~ to abuse, compn-~no at ~ea~ t~ lAy~rs,
in~luding:
~ J6 Y! 16~Zg6~o8~ Z~ ! Z~-z ~ Vd r ~
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a~ ~ tlrst au~slde layer s~l~ct~d ~rom ~ha g~ Jp cornpr~in~ lJi nPF, EVA a~d
blond~ ~ VLUPE an~ EVA; dnd
C~ a 5~and outside layQr cQ~p~1sin~ EM~.
Prer~ra~y a cor6~ or int~rn~l ldy~r b~ ;nclud~d, wh1ch ls
pre~srab1y as hor~inb~for~ d~cr;bad. Al~arnatjv~ly the cor~ l~yer may
con)pl~;sQ ~ross-llnk~d EY~.
~ refer~bly the l~rct ~uts~de layer ~s as h~relnbef~re descr~ed.
9~rriar ~ndfnr Adh~tve layers ~s herelnbe~ore descrlb~d may als~ ~e
tnclu~ed 1n thls ~orln of the present tn~lentlon.
In a fllrther a~pect the prcs~nt inY~nt~on comprlses a process ~f mdking
h~ shrinkable mu~ y~r fi~ln, comprisln~;
~) co-~x~rudin~ as a mu~ttl2y~l~ filnn preeUr~or l~m~nate, a~ ledst three
lay~r~, lnclud~ng:
a) ~ flrst ou~slde layer ~e1ected from the ~roup compr;~;n~
EVA, YLDPE and blends of VLOPE and EVA,
b) a care Dr lnternat lay~r,c~mpri~iny ~n iQnon~r ~r ~ bie,ld
~h~reof with EVA, EMAA o~ EAA, ~nd
scor.d outslds t~y~r ~ ctQd ~rom 1~ g~oup ~olnpri~;ng
EMAA, EAA and lonomer~t ~n~l
(il) ~ubs2qu~ntly tr~tin~ tho precurs~r ~o pru~ide th~ multllQyer
fllm.
g~ #'lg~ T ~S~L~ ~Z~ Z ~ ! NOS ~ ~ r ~ ~S
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Pr~ferably sald proC~rsor lanlnat~ 19 gtn~ch~d by r~cl~ing ond~r
blowin~ tQ a dns~rad fi1nl, thickn~s Lo th~reby proride th~ h~ t
shrlnka~le fil~.
Pref~rably sa;d ~r2~urs~ min~te l~ sl:r~tched ~y ~lrst heatlng
ie to sof~enlng point, thon ~xp~ndiltg ;t by blowtn~ ertioal bu~ble
to strot~h the lom~n~t~, c~lin~ ~ho ~a~lna~e ~nto ~hln f~lm, ~nd
~11AP3;n9 the bubbl~ onto conver~tllg rolle~s, then w1n~ng ~lR f11
undor ten~lon lnto roll fQ~m.
Preferably 9~1~1 stro~h1n~ ~S ~O ~l~out S to ~ Q~ th~ surPac~
droa ot eh~ tllm precl~rsor.
Preferabl~y ~id pre~urs~r 7el~ te h~s A toee~ thl~kne5s ~f fr
about 400 n1lcr~ns t~ ~Ibout 8~0 m;cr~ns. P.ef~rabl~ s~id ~RCQn~
outsldo l~yer c~ of s~ld pre~l~rs~r l~lmlrl~te has Q ~ichn~ss ~ ~bwt
75 t~ ~bout 1~5 mi~r~ns.
Pre~erably sa~d core or lnternal lay~r ~ sald pr~urssr
ld~lna~ hdS a cnickness of l'rom a~out Z0~ to a30ut 410 m~crPnS.
Preferably said first ou~side l~yer ~! ~f said precursor 1dmina~
has a thickn~s of from about 125 ~o ob~u~ .5~ mi~rons.
Pre~ara~ly sdld multilaYer Fil~ll h~l5 ~ r~sul~dllt to~l thlckn~
of about 6Q to a~out 120 micrcns.
In a ~ur~har ~p~c:t th~ pr~en~ ;nvont1On ~ompri9~& a prnc~
~aklng a mutt;1~yor f~1TI COI1IPr;S1n~:
SZI' ~'16~66~0~1 8S~ C~ ' W~8Z:~ ' Z6-Z -~ ' NOS ~ ~d P ~ 3S
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~i~ co.ax~r~djn~ dS a mulLlldyer ~l~m precursnr l~mtn~o at
least two layer~, ln~lud~n~:
d~ a ~trst au~ld~ l~y~r ~lect~d ~rom the gr~up c~mpr~sl
~ L~PE, EVA and bl~nds o~ VbQPE ~d FVA,
c~ a seccn~ au~gl~ lay~r c~pris~n~ EMAA; ~nd
(1t~ ~ubsequ~n~ly traa~lns th~ pr~cllrs~r to prn~7~ ~h~
mult~lay~r fllm.
Pro~erably ~ cor~ layer b~ ig ~Isu ~cx~uded with 1~yers ~) ~nd
c ) .
Pr~f~rAbly s~d mut~tl~er f~lm i3 ~5 hereln descrlbed.
The pres~n~ 1nv~ntlon w111 nnw b~ d~scr1~d ln more detail, wlth
r~t~rence to ;he acccmpanyin~ dr~wlng6.
Figura I ~how~ ~ ~hr~e l~yer ml.~ltil~y~r helt ~hrlnk~lo T~lm such
~ can ~e producnt by e~trust~n, ~or ~n~ontence ~ ilm thi~kn~3ses
b~n9 shown substan~;ally identicQI. ;t will b~ dppre~;4~d th~t it
19 not es~cntlal th~t the film ~f th~ present InY~ntion has ~hreÇ
l~yer~ - ~rom t~ t~ ~our or Inore l~y~rs m~y be used.
F~gur~ 2 i5 ~ dlagramIna~le view of ~ ~hre~ y~r precunsur
lamln~t~ ~h~Ying how lt is te ~ hlown ~ n to ~ fil~.
tn one pre~erre~l for~ f tne present inYe~t~n the ~ult~lA?,er
~ilm has th~ee l~yer~. L~yer a) ls preferdbly th~ so-~lled ~utsld~
la,yer, whlCh ~n use ~when ~he fil~ i5 ~sed as a ~r~pplng, ~r to de~ine
a contAin~ or p~cka~ will be thd~ surf~ce ~hich ~oes not cnntact
S~ 168Z~:P6081 -8g~.L~ : W~ Z ~ r ~:A~
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th~ product, Layer c) ts pr~forably the lnn~r sedlln~ ldyer, which in
use wlll b~ tha~ surf~ce lik~ly to cont~c~ the foods~f~. Lay~r b) ls
th~ ~ore or intern~ yer.
L~yer c~, th~ inner ~alin~ 1ayer, may cDmprl~e ~MAA, EAA, or an
lonQme~. ~MAA is esp~ciall~ pref~rr~d, i;nc~ us~ of E~A~ ~opolyr4r
pro~;des the film with Yery qood ~ea1ab jl j~y pr~pertl~ p~rtdnt
~hen there ~y ~e co~t~mln3~10n o~ th~ material, ~or ~xampl~ by
rti~ulatQs, and/or pteats or fcl~s in tha matrridl. A ~ayor c)
an ~nomor al~o ~onf~rs ro~onably go~t e~41abillty prop~rt;es cn th~
fil~, 31~h~ugh ~ non-ionis~ fo~n af ENAA 15 pneferned in thts
r3spact .
L~r b), tho cor~ ~r lnt~rnAl Idyer, may con~rlsa eith~r an
~onomen (pr~ferably sQdlum ionDmer polytn~r~ or ~ bl~nd th~r~oP wl~h
EYA. EMAA ~r EAA. ~i ex~n~1e, tne Intarna7 7ay~r cou1d compr~se a
b7end of sod~un) I~n~r polyD~r ~it~ up ta a~out ~/~76 EVA, more
pret'erably up to 2W EV~, or a blend ~ wd1um ~onoIner polym~r t~l~h up
tt~ dl~OUt 25S EAA or EMAA, ror~ pref~ ly from ~bout l9~ ~Q ~bout 10
b)~ wal~ht of EMAA ~r EA~. The i~nom~r provlde~ th~ fllm i.ith nigh
shrink ~nd hlgh clari~y prv~ertto~. it l~ als~ p~ss~ble f~r this
l~yer to collpr;se ~ome o~her hs~shrin.k~ble ma~erlAl, ~ h as
crost-linked EVA. layers c) ~nd bi aIso ~ he film goad l`~SiSt~lllC~
to internal pun~turln~.
Lay4~ a) tthe "ou~sld~ yar"~, in on~ pr~fQrred for~ ~f the
lnvantlon~ Inay ba a b1en~ ~f ~b~ut 50~ ;vlopE wi~h About 5~ of EVA
c~polyms~, ~lthou~h bl~nd~ of Vl~PE ond EYA ~ont~ning up ~ ~bout 7
E~A, o~ ~v~n EYA dlone, n~y ~lso be u~d. Thl3 l~yer pr~id~s th~
~ZJ6 ~!T~8Z6~EOEI ~ W~Z:~ ' Zg-Z ~ N~.~ r ~ a6
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fllm wlth 9~Od extorn~l ~buse res~stdnce propert~es, while ~t th~ s~me
t1me haYlng a ~lossy appearanc~ w,h~n 5hrunk, nnd a s~o~th printable
sur~ac~ ~lnlsh.
It ~s als~ p~sslb1~ for there ta b~ ~n additi~nal l~yer, for
example dn GXy~ll barrler layen, to en~ure tha~ the Till~ is
~ub~antially i~perneablo to ~s transmls~ion ~a;nly oxy~en)~ Th~
barrler lay~1~ cou1d compr;se ~lly ~f the ~Je~l known re~lns useful in
enhancin~ oxygen barrl~r proPer~ies in a film o~ ~a~. 7h~e lnclucle
~Inylidene chloride Yinylchlorl~e copoly~nor, ~nylidene chlDrid~
methyl ~ryl~te ~op~ly~er, eehyl~ne ~nyl alcDhol ~op~lyner and
polya~ide .
Adhesl~ lay~ri ~y ~ usad ~ither to adh~r~ ehe out~id~
VL3PEJE~A layer to th~ ra ~pr~fora~ly ionomer) la~r, nnd~or to
~dh~r~ ~n oxyg~n Sarr1~r l~y~r, ~uch a~ PVDC or M~, t~ ehe oth~r
rs. App~apr;ata ma~el~ials for ~dhesiYo l~v~r~ wh;ch n~ e us~d
inrl-lde E~IA, FM~A, EM ~r lon~lnor. Passl~le ~tru~tu~s whlch ln~ d~
~he uso of ~dhes;v~ l~yer~ ~w;th ~ thul~t d b~rrler l~y~r~ may ~e:
6-1~yer structure:
~Dp~EMA~py~clEMAAllcN~MERJ~M~A
a 3 c d
a = outslde layer
b ~ adheslv~ lay~r
c ~ b~rr~r ldyer
d n adhesll~o l~y~r
e~ internal lAyer
f ~ lnn~r s~aling lay~r
or (2l a 4-loyer ~ructu~e:
~LDPE~EMAA~ SûN~lERf E~4A
a b c d
a ~ out5id~ r
b = cdheslve tay~r
c ~ int~rnal ~yer
d = lnnQr s~allng lay~r
g~ 68zg~g;)9t ~g6Z~ 10~:~: Z4-Z ~ ~,1 r
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In these ~tructure~, EAA ~y b~ u5~d 1nstead o~ EMAA.
~b1e 1 shows th~ structures ~ 3 ~ erent multll~yer ~three-layer~ films
n ~ccordancc ~l~h ~he pr~sent 1nvs71tIon~
TA~LE l: THE Pi4C~;A~iNG STRUCTURES
~-=~J~ ~_~D==~=~~ ~a~tc~ -3~ =~a~s
STRUCTURE N0. 1 Z 3
LArER ~ (lnsld~)
Resin ~e~ ~o7ow~ A ~ C
Th~knQs$ (mlcron) qo go gO
~olerance ~f-10 ~-10 ~/-1û +~
LAYER b~ ~ore
or Intqrnal)
Restn ~5ee bolow) A A D
Th~ohn~ mlcron~ 235 235 23~
l'oleran~e-~f-20 ~I-20 ~ 20 ~1-20
LAYER ~ utslde~
Resin (see belo~) ~ B 3
~h~kn~ss ~mlcron) 145 1~6 146
roleran~e ~-20 I~a~ 2~ 20
__~~ ~~~___~_~__-___~_n_~____~_______-________-___n
TOTAL T~rc~HEss ~F
PRECUR50R ~AMINAt~:
~mlcr~n) 470 4~ 470 470
rol~r~n~e ~/-F0 ~ 0 ~/~^50 ~/-S~
~ AA ~ A--~ ~ A '; ~ ~ A a AA ~
BL0~ UP RArlO: 6.76 6A7~ 6.7
RESllLTANT FIlM
THIC,YNESS (m~ct~on~ i ~0 ~0 ~0
roler~nce ~~5 1~^~S t~A5 ~t~5
A~ A_l-- A ~A~ A~A~ A A~.~W~ A~ A~A~
RESINS;
- Sodlum lono~er Polyl~er, speciFic graYity ~Ss) 0.94
8 ~ Pl~nd o~ Su~ by w~t~"t of V~ry Low U~nsity Polye~hylcn~
~EqPE), ~ 0.~1 with 50~ ~f Fthylone Y~ny1 Ace~e~^ ~E~A)
~opoly~er, sg 0.~3.
E~hyl~ne Metha~rylic Acid î,opoly~r~EMAAJ,~g O.g4.
D - 81en~ of 93~ of Sodiu~ Iono~ P~lsner, so OAg4~ wl~h 7~ of
E~A C~poly~o~, a~ 0,96.
S~i~J3=_AA~AA~ A~ A~ n--=~ C~rA==~
SZJ11$~ 6~081 ~ Z~ dO~:I,: Z~ r ~ S
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~ha ~n~r~1 properties of th3 fin~l p~ckagln~ structures ~r~,
3. P~rc~nt ~rink at ~CI
longl~udJ~ d~r~ct~on) ~ 35 ~ 45
TD ~tran3v~r~e t;rection) = SO to
b. T~n311e Str~n~th in kg/sq C~l;
~ ~ 400 to S50
rD - 4~0 to ~
c. P~rcent El~n9~tion:
LD ~ 120 tO 1
TD l~O to 25û
rhe packa~ng per~ormance ~hari~cteristl~ o~ each tay~r in ~A~h
structure ars dependent on th~ r~ h~ing us~d~ T~Q 5har~C~ar1~ttC~
may b~ generallsed as follows:
~tRUCTURE l:
Ltlyer~ c) ~d b) E~sy se~ tv thrnllnh c~nta~lna~n and
pl~ts.
Hl~th cl~r~t~ ~nd h1gh 5~ink.
~30d r~s~s~anc~ to 1ntqrnal puncturlny.
S~JZI~!16~ZC~Ca81 -~tl6~ZLg ! ~06:~ ~ Z6~Z ~ ! ,N~6 ~ r V 1~ a~
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I.dyer e~ 3y ~ppeararl~e when shr4nk.
Goo~ resis~anc~ x~ern~l Abus~ punotur;n9.
S~oo~h prln~c~lo ~urf~e finish,
ST~CIURE 2l
Lcy~r e~ ~ ~ASy s~labi1~ty ~t l~w ta~peratures t~ro~gh
c~nt~m~natl~n an~ plea~s.
Htgh clarl~y.
~ood r~tstanc~ to l~rna~ pun~turing.
Laysr b) Hiqh ~l~rity and hi~h shrlnh,
Gcod r~slst~n~e to internal punc~ur~n~.
L~e~ a) ~ S~r~ ~3 S~ucture 1.
SrRU~TURE 3:
Layer c) ~ Sa~e dS Struc~u~ z.
Lay2r ~ - s~lne ~S Str~cture 2.
L~y~r ~J ~ Sa~e dS Structure 1.
Table 2 shows ex~mples of al~crna~l~e stru~tur~s af nlul~;-layer filn~c 1n
aGcardance with the present Inv~ntlurl, ir~ which lay~r a~ ~t.h~ outsld~
layer~ compr~se~ EYA capo1y~er alon~. ln th~se ~tructurss, layer c) ~th~
tnsidQ c2~11ng l~y~r~ c~nlp~isas EMAA or EAA (~p~c7~ ravlty ~ 0~
!ayQr b) ~th~ cora lay~r~ ~en1pri~as ~od~um ionomllr b1~rd~tl w1~h CMAA or
sæJ~ szs~sl ~S6~Z~ J~ Y~ 3S
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1198
EAA at d rat~o of 5~6 b,y 7~0;9ht of EMM ~r EAA ~ono~r ~pet:Sf;~: ~ravl~y ^
0.~4); and l~yer a) (the outsi~ yer~ comprigg~ E~A ~poly~el~ ~spz~lc
gr~tty ~ 0.96).
Table 2 Fur~h,~r,P~c,,k~ging Structures
Structure No. 4 5 0 7
_ _ _ _ ~ .. _ . .. ,. ~ .. ,. ~ .. _ _ _ _ _ .. .. ... v .. ~ . c .. _ ~ _ v .
L~yer c) ~ln~tde~
Resi~ (~ee bel3w) C C ~ D
Thlckn~ss ~m~çron~ 90 90 90 90
T~lera~ce ~t-lO
L~y~r b) ~core~
Resln ~Sdd h~low) E G E
Tn~ckness ~icron) ZW 2~0 2nn ~oo
~ol~ranc~ 2Q
Lqyer a) (out~ide)
Res~n ~see below~ F F F
~hlcknes~ ron~ 180 .t80 1~0 18
Tolerance +~-20
Total thlckness
~f pr~c~rsor lAmln~te
~ icr~n~ ~70 47~ 470 470
Tolor~nce ~50
Blow Up Ratlo ~76 ~.76 ~.7~ 6.7
Resultant ~11m
~htckn~s~ ~micron~ 8~ 80 B0 80
~ol~ranco ~f~50
R~SIN5:
C = 'thylene Meth~cryl;c Ac~ Capolymer !EMkA), s~. 0.94
D ~ Ethylene Acryllc ~tcid Copolylnor ~Ah), ~. Q.94
E ~ ~lend of 95~1 s~dlum lonhmer p~7ymer ~Nith 5t~ ~MAA copolymer (lono~ner
~.~. 0.94)
F 'Y~ cop~lymer
G G Blend of 95~i sodillln l~nolner polym~r wl~:n 5X EAA copaly~n~ J. n.
tne prec~rsor ,~n~ndtes aldy 4~ Infld~ hy USill~J ~ ~hrr~ yen
co~xtruSlqn pl~ocess ~ ~x~mples ~ th~ res~ns And p~f~rred lay~r
thicknesses 3re spe~ d ~n Ta~les 1 and ~, Th~ thicknesses of the
SZ~tz:~68Z~ s~ t~;0 ~ ze~ ,YOS ~ ~fd r
S~NT 3~:x~rox Telecopier ~1020; 2~ 2 ;12:47PM; 13~3433Z831~ 9l6l3232a44~;#l5
, ul .~. u ~ u~ .n i ~7;~9~ laO~ s~ 2~ ~
-13-
v~rious l~yt?r~ ~re ch~sen ~o as to prov~de an ovQrall ~ult~lay~r ~lm
thlckness th~t ;s des;l~d. The tot~i thiekne~3 of ~h~ precurson l~mtna~e
ls pref~r~bly ~n th~ rang~ ~ al~3ut 400 to ~20 rnicr~n~.
A,~er the prec4rsor la~ln~t~ ha~ been l'cr~ed, lt 15 ~rlen~ y
f;rs~ heating it to sot'tening polnt, t~e~l axpandlng tt by 41D~;n~ a
vert~cal bub~le. Th~s stre~oh~s ~lle ldmtn~t2 inco a thln ~ whlch fs
ca~led. The bubbl~ is collapsed by conYer~ln~ rollers then ~aund under
tens;~n into rol~ for~. ~n this re~ard, Fi~ur~ ~ ~hows hoq th~ precursor
la~inac~ is ~o ~e blo~n down ~o ~tlm.
Alternatlyely, ~n~al~ frame str~tching may bo used to s~r~ah the
pn~cur~or lamin~e.
~ ha ~rQtch;ng procsss orients~ss t:h~ poly~e~ ~olecul~s ~nto
longitudinal and transvqrss dlr~ctions ~a and ~). The a~ount of
tch ;s ~ile Blow IJp R~tlo whlch ~s ~p~clfted ln Td~ he
preferred 81OW Up Ratlo i3 ~sb~ut ~.76. Th~ ~ot~t ~hkknass c~ tho ~
ftlm ~fter cc~xtrusion and orien~t~on~ i~ pr~f~rabl~ frn~ about 6d to
~20 ~lcrcn~,
Other processes kn~wn in th~ ~r~ such ~ ~rus;~n contin~, ~nd
con~Qn t~nsl lamlnatlon, m~.y als~ be u5ed tD m~l~e ~h~ prec~lrsor
1 a~l n3t~s
Optl~nally, whQn the Inner sealln~ layor c~mpr~ses EMAA br ~AA, ~n~
tha c~r~ l~y~r ls n~t a-l lonomer ~ when the c~re layer ~mpri~ E~A)
the ~ca~ing layer, th~ c~r~ lay~r, and an~ ddditional l~yers loc~ted
betw~en the cor~ and se~lfng l~y~rs, may be cr~..l1nked, usln~. fDr
ex~mpl~, irr~diat~on.
SENT BY:Xerox Teleco~ler 7020 , 2~ 92 .I2~47FM; laO34332a31 ~ 1~u~491~6Jl32328440.~16
98
-13~.
I~ lS ~elleY~d tha~ a ~ul~lldyer ~llm ~n accord~nce wlth ~he pr~sent
fnvontton wil1 provld~ n mult11~y~r ~llm hav~n~ goad ~b4s2 r~sf~t~nc~
propertidsl both t~ in~erna1 ~nd ox~o~na~ punce~r~ng ~du~ to tho p~eson~
of a la~e~ comprlsin9 ~ blend ~f VL~PE~IEYA or E~A~, whllu at ~h~ same
tlme h~vin~ good hsa~ ~hr;nkability, h;gh clar;ty ~nd good s~21abllity.
