Note: Descriptions are shown in the official language in which they were submitted.
~ WO 94/1204~ ` 2 1 4 9 ~ 2 0 ~sg3/l066g
,`.;
- PATENT ~4PPLICATION
COATED MEMB~ FOR CONTROLLED ATMOSPHERE PACKAGE
~ :~
~....
CO~TED MEMBRANE FOR CONTROLLED ATMOSPHERE PACK~GE
TECHNICAL FIELD ~ -
20 ~ ~ This invonbon relates to the field of packaging for respiring items such
8 fresh
a~ vege ables and more particularb to~ a coated porous membr~ne for use in
controlling~ the flow of oxygen and carbon dioxide into and/or out of a produce - `
c ntaincr.~ -
BACKGROUN~ ART
~- 25 It is well-known that the eating qualities and/or appearance of respiring items -
such as fresh fruits, vegetables and flowers (hereinafter "produce") can be preserved
by controlling the atmosphero insido of the package that holds the produce. For
- example, U.S. Pat. No. 4,842,875, issued to H. A~derson on June 27, 1989, describes
; a basic ~oach t~ involves controlling the flow of oxygen and carbon dioxide ~nto
a~d out of the container that holds the produce. The container, called a "controlled
atmosphere p~cka~,~' is compr~sed Qf a subs~antially g~s-imper~neable pack~e
having one or more panels made of a microporous plastic membrane having an
oxygen permeance in the ra~ge of 77,500 to 465~000,000 cc/m2-atmosphere-day. By
- varying the permeance and/or size of ~e panel, various optimized oxygen and carbon
; ~;` 35 dioxide levels inside ~e package can be maintained for extended periods of time
~oreby pro~nding a method for retarding the maturation processes of various produce
commodities.
:
'':~ , . ' '
, . .
~ 2~ 9~ ~11JS93l1066s
U.S. Pa:t. No. 4,9~3,703, issued to ~ toon on May 8, l9gO, desc~ibcs a ~:
microporous;filr~ for usc a~ a p~ol is~ a contr~lled at~osphere p~ckage~ compnsed
of a unia~dal1y olicnted polyolcfi~ film w~th an ineIt filler.
~J.S. Pa~ No~ 4,9~0,032, issu~d to M. Ant~on on ~Ssrch ~0, 1990. dcscribes
S a con~ollcd a~anosphcre pacltagc, h~g ~ fissf. memb~no comp~iscd of a u~ lly
or bia~ially (~ric~lted polymcr f~lm ~at is pcrme~blc ~o oxy~en ~d carbon dio~cide,
asld a se~o~ membr~e ~at is perlnc~bl~ to wa~r but impermeable to oxygcn and
on diox~
U.S. Pat. ~o. ~,879,0?8. issucd to M Ant~n O~l Novcmbor 7, 19891 ~d U.S.
Pat. No. 4,~23,650, iss~ed to ~ ~Lntoon on May 8, l~90 dcscnbe me~ods for
pre~g ~n~croporous films that cao bc u~ w~ olled a~nosphe~c paokaging for
produce.
.~dd~ ents ~t de~l ~rith t~is ficld includo U.S. Pat. No. 4,939,030,
is~ucd to S. Tsuji ct ~1. on ~uly 3, 1990, ~ich dis~loscs a ~e-layer fillm, includis~g
a vinyl ~e layer, for use ~ producc packa~; ~nd U.S. Pat. No. 4,g~6,071,
issued to 1~.~ Bcll on Febr~ 26, 1991, which dlscloscs varjul~ ~e ~cc arca o~ .:
~e film to ~n~ol ~he a~nosph~e inside of a produce package.
Additi~l pate~ts toali~g ~it~ ~is field but w}lich ~se not conside~cd to ~c
:~: ~ten ~ to ~he prcsent inven~on i~clude U.S. Pa~ ~lo. 3~62~.876, s~d to C. F`itkD
on Dece~cr 7, 1971; U.S. Pat~ ~lo. 4,'769,~62, issl~cd to A. P~ar et ~1. on
Scptemb* 6, 1988; and U.S. Pat. ~o. ~,026,S91, issued to R ~Icnn d al. on une
25, 1991.
All Oe ~s p~r ~ ~ that in ortw to cstablish asld ~Pintain dîffcrent
~-; oxyg~car~on dioxide ratios i~ide of ~e pac~agc, citber ~e p~rmcance of ~e
microporous melnbranc must be ~hangcd by altering thc chcsuGd îormulation of thc~: ,fi!n- ~ to ~ the m~e~ or ~e ~ize of ~he membr~c pand must bc
c~anged.
~ ~ The p~eM invc~ion compnses ~ ed porous membr~ne panel for use ~th
- 30 a containcr that holds produce. The coatet porous membr~ne pwl is positionc~ in
cont~ct with and ovcr ~ hole ~n, a s~bstantially ~n~porous container for pro~nding
an area ~ough which a limitcd ~olumc of caroon dioxidc and oxy~en can f~ow at
i~,
, ~,
,, ' .
wo 94~ 214 9 ~ ~ O pcrNs93/lo669
a rate (permeance) between the inside of the container and the outside ambient
atmosphere which is within a range specific to the type and arnount of produce in
the package. The combination of the non-porous container and the coated porous
membrane panel retards the matura~on of the produce by allowing the concentration
5 of oxygen and carbon dioxide inside the container within a rang of concentration
reasonably optimal for the type and arnount of produce within the package. The
coated porous membrane panel of the pr~sent invention may be comprised of a base- substrate such as polypropylene or polyethylene, a nonwoven substrate made from
these polymers, or paper (hereinafter "substrate") which has a permeance rate tooxygen and carbon dioxide in a range of, for example, 77,500 to 465,000,000 cc/m2-
- atmosphere-day C5,000 to 30,000,000 cc/100 in2-atmosphere-day). This range is then
reduced to a desired level suitable for the type and amount of-produce to be
- - packaged by applying to said substrate a coating of a porosity-reducing, film-forming
substan¢e, such as an acqlic-based polyrner, which by is coat weight (~ickness)
- 15 and/or pattern of application, decreases the permeance rate of the substrate to a
desired range of permeance rates. The percent reduction in the oxygen and carbondioxide permeance rate of the substrate can be varied 15 percent to almost 100
percent by varying the aforementioned characteristics of the coating applied to it.
The coated porous membrane panel of the prese~t invention differs from the
porous membrane panel described in the prior art ~e.g., by Antoon in U.S. Pat. No.
4,879,078) in that the prior art varies the constituents of the membrane material to
produce membranes of varying perrneances, whereas in ~e present invention, a
single substrate can be used to produce difference membranes for different typesand/or amounts of produce by simply varying the characteristics of a porosity-
25 j reducing coating mat!eria~ app!,ied ~to the single substrate.
BRIEF DESCRIPTION OF DRAW~NGS
For fuller understanding of the present invention, reference is made to the
accompanying drawing in the following Best Mode of Carrying Out the lnvention.
In the drawing:
Figure 1 is a schematic cross-sectional representation of a coated membrane
according to the present invention.
~4~ 2 1 4 ~ ~ 2 0 ~S93~
Figure 2 is a top view of a nlembr~ne h~g ~u coding a~plied in a tria~
patte~
Figu~e 3 is a ~op ~iew of ~ me~brano ~aving t~o coating ap~licd as a solid
pattem.
SFigurc 4 is 8 cross~ oDal ~riew of a co~t~i~ accord~ng lo the present
invenffon.
Figurc S is a schcm~c c~ secdosial r~:sentadon of a coated membra~le
h~ving ~ ~ layer and an ~vc laycr.
Referenc;e num~s re~r to the æamc or equi~rale~t pa~ts of the prcscnt
10invendon thro~ e sevelal figures of ~ drawing.
EST MOI)E OF CARRY~ )UT 1~ INVENTION . .
Fi~.~ I i4 a sch~na~c illus~ation of a co~ted membrane 10 aceording to ~e
present i~L Thc m~ane~ 10 com:p~s a su~stratc 14 ~nd a coa~ng 18 ~at
is ~pplied~ to a surf~ l6 of t}le su~ale 14 ~o dec~c dle penneance of substra~
15~ ~14~ o~ en:-~and~carbon dioxit~. ~ Thc wf~c~ 16 is~ cc of ~e substrate ~
i which ~ d catlx)n dioxide mt~st p~ss ~n: ordcr to f)ow through thc
subs~ 14 ` ~ ~be any ~ matcdal having ,thc fol~ounng
: t~e p~ility to oxygc~ ~uld be in thc ra~ge of 77,s00 to
20 ~46~,00(~p00~-a~p~ue~y~5,000to30~ 00¢cJl00in2-~mo~ph*e~day);
w~pr~ (3)~thc co~ ~ r~t~o~of thc su~ e 14 can range
8:1~ ~wi~ ~o~ p~ed ~r~ge ~e l;l to 4~
n t3~::ps~rcd~e~odi~ t~o subst~ 14 is a micropor~us polypropylene
2 5-ftlm:~such~as~thc fil~n ~ibod by AMsoA in U.s. Pat. No. 4,879,078 (i.c.,
;: c~mpriset o~.a ~lb ~d f~ comprisct ~f a blcnd of 36% to 60~ by
- ~idght of pro*~ o~r or~=~ copolynler, 36~ to 60% `
of calcium c~ filbr l~ased on~thc total w~g~t of ~e pol~ner ~d fill~, 0.10-
: 2.5%~ by wéi~ht~ of c Icium ~s~`~d 0-1.S% by WCigtlt of stabilizer). Alth~ugh
30 ~.tli~c~i5 ~0 pr~:frcd sh~ or s~zc fo~ ~e membr~e 10, for referenx purposes only.
bs~e 14 ~11y }~s a Icn~ "~ thc rangc of 1.0 to 4 î~ches and a
thidl3i~s ntn-in thc ~a~o of 5.0 to 10.0 mil. ~n general, any of ~c pol~mc~s
",,"~ ,
...~
~ W094/121~40 2149920 ~ ~/U593/lOCC~
described by Antoon in U.S. Pat. No. 4,879,078 can be used as the substrate 14,
including the polyolefin homopolymers described therein.
Numerous other materials having the characteristics listed above may be used
as the substrate 14, including the microporous polymer films described by Anderson
in U.S. Pat. No. 4,842,875 that utilize a variety of inorganic fillers such as clay,
barium sulfate, calcium carbonate, silica, diatomaceous ear~ and titania5 and those
using organic polymer fillers such as polyesters, polyamides a~nd polystyrene.
- - It has also been observed that the substrate 14 may be comprised of a coated
or uncoated paper having a weight in the range of 55 lbs. to 110 lbs. (e.g. the
TEXAPRINT brand paper or white ClS latex impregnated paper manufactured by
- Kimberly-Clark?. The clay coated paper should also have the permeance and
compatibility characteristics listed above.
- - - The coating 18 used on porous substrate 14 may be any material that- substantially reduces the perr~eance of the substrate 14 to oxygen and carbon
- 15 ~ dioxide. ~Such rr,aterials are typically riferred to as "barrier coatings" and include
~- acrylic ~emulsion polymers, ~polyvinyl acetate homopolymer emulsions, and
~ ~ ~ rutrocellulose~polymers. For practical reasons, o~er desirable characteristics for the
;~ ~ coatîng 18 irlciude: water resistance, FDA approval for indirect food contact, and
good film forming qualities, namely the ability to form a continuous barrier coating
18 that can bè~appl ed to the substrate 14 without the form~ation of pin holes.
; In the~preferred emhodime~the coating 18 comprises an acrylic based
polymer supplled by Johnson & Johnson under the trademark JONCYRYL 74F. ICI
also rr~arkets an acceptable acrylic based polymer under the tradernark NeoCryl~9
which may be used as the coating 18. For reference purposes, the coating 18
25 ; generally has a coa!t Iweight of ,about! 45% (i.e. about 4~% by weight of solids), and
a thickness "f" of about 0.25 to 0.5 mil. When paper is used as the substrate,
porosity-reducing coating layer 18 rnay consist of the ink used to print information
on the paper (i.e., experunents have shown that 80-lb clay-coated paper, for example,
absorbs sufficient ink to reduce the permeance of the paper approximately 70%).
The coating 18 may be applied to the substrate 14 in-line during a label making
process, or the substrate 14 may be coated off-line using standard printing processes.
., .
` ~ 2 1 4 9 ~ 2 0 PCT~S9311066g
In the l~bel manuf~ctun~g procoss, ~ roll of sub~atc ma~e~al is ~nve~tcd to
pressure-SCnSiliVe ~dhesive la~els. The conwrsion p~oce~ i~volvoi r~ng a roll
of substr~ m~terial through a label m~ufact~er's prin~pres~ whe~e the su~strak
m~ial's top ~ur~ce is pnnud wi~ inks, tb,e pe ime~r of ~e back su~f~ce is coate~wi~ adhesiv~. tho labols are die-cut into desired lab~ pcs, and the resul~
master roll of la~els is slit ~nd wound into indt~idual ~lls of hbels ~st are
dispcns~d ontc packages b~ tho fo~ packcr.
~ lcxography is a ~ndeiy used process for prin~ng roll-fed pressure sensi~ve,
self-adhcsîvc ~Is. Flatography is a relief-pn~ng tcchnio~u~. The fi~st stcp is to
10 make a flacibk pi~nting plate of rubber OF plastic, with the print image area of the
plate rai~ct a~ove thc nonimage arcas. Thc flexible plate is wrappcd arGund a
cylinder and pdaced in one of several printing ~tions af a flexographio press. lnk
rollers on the press touch only tho~top surface of ~e raised image arca of t~e flex~
platc,~ s ~nsfarcd dir6~y from the îmage arcas ofthe platc to ~o subs~te
to be pr~ted. Af~ applying t~ ink ~ e top surf~ of the su~ate, adhcsivc LS
applîcd to the~-~ surf~c4, and tbc hbels are p~#ed:duough a d~ying 5uti0Il, a dîe
cottiDg st~ion, a~d~wound~ o~ a t~-up rolL
Fla~ p~ir~ prOca#es and grawre pri~ p~oce~ are descri~d
in~thc~book~ "E~jMj~j8~ lnk llandboo~" comp;led by Product ~d rwh~ical
:~ : 20 Publi~ons~qommine~ ~:a~nal Assoc~ation of Pri~ti~u ~nk Man~er~ I~c,
1976.
Fig. 2 il~tes ~ top ~iow of tbe coa~ed m~mbnme 10 ul which ~c cna~ng
18:~ is; ~d a~ a ~qad~g~ pnn of trîa~lcs ~ g ~e flexographic process. In
Pig. 2,~c ~ tr;~lnglcs 24 ~l ~eas to which t~e coa~ing 18 bas becn ~pplied,
`~ 25 while the ~igbt. ~ nglcs :28 rcprcse~t ~ to whieh no coating has becn appl;et.
Thercforc, ~e ligbttrîangles 28 rep~t thc exposod surfaco 16 of the subs~atc 14.Similarly, i~ Pi~ 3 thc O~Dg 18 ~ ~d by a t~sk aroa 32 ant the
K~cd s~ 16 of the ~e 14 is represented by ~e light ~rca 36.
coa~g p~ illw~ed in ~i~s. 2 an~ 3 ~ illus~ati~e of a ~rirtually
30 u~limi~ed: numbcr of possible coa~ing pattt:rns. Any pa~ern tbat decre~ses the
rca of the ~ubstrate 14 is accepta~lo ~or usc in th~ prcscnt
in~cnt~on.
__
~ wo 94/12040 2 1 4 ~ 9 2 0 pcrnl593110669 ~
Fig. 4 illus~ates a rigid container 40 for.holdirlg respiring produce 44. The
term "respiring items" means items that respire in the biochemical sense of ~e word
(i.e. that take in oxygen and give off carbon dioxide). The co~tainer 40 is comprised
of a sllbstantially irnpermeable packaging material 48 that surrounds the produce and
holds it in a charnber 52 formed by the packaging material 48. Tbie container 40- thus prevents any appreciable exchange of oxygen or carbon dioxide from within or
outside container 40 except through thie membrane lO.
In t}iie preferred embodiment, the packaging material 4~ is approximately 15-20
mil thick PVC. However, as is described in U.S. Pat. No. 4,842,875, any
substantially impermeable material suitable for packaging produce, like glass, m~tal
- -or a wide range of plastics (e.g. polyolefins and polystyrene) can be used for the
packaging material 48. The term substantially impermeable is defined in U.S. Pat.
No. 4,842,875 and means that no appreciable amount of oxygen can pæs through thepackaging tnatcrial 48.
In Fig. 4, ~e container 40 is shown as having the shape of a basket with a
bottom ~part 56 and a top part 60 that fit tightly together in a gas-tight manner
Howover, it should be appreciated that the container 40 can take other forms, such
as a 3 mil thick polyethylene bag, having a 4.0% ethylene/vinylacetate content. The
only ro~nrcmonts for the container 40 is that it be comprised of the substantialb
impcrmoablé packaging material 48 and that it surround and hold the produce 44 in
a chambor 52 so that the only~passagcway for oxygen-to reach or leave the charnber
52 is through thc mcmbr~me 10.
-~ ~ An aperture 64 exists in the container 40. The aperture 64 is an open region
(hiole) in the container 40 not covèred by the packaging material 48. The membrane
10 is posidoned over or about the aperture 64 so as to prevent gasses such as oxygen
anid carbon dioxide from passing between the chaimbér 52 aind the iambient
atmosphere without passing through the membrane lO.
- Fig. S illustrates a membrane 70 in which an ink layer 74 has been printe& on
top of the coating l8. The ink layer 74 is comprised of ink, water-based or
~; ~ 30 otherwise, that is permeable to oxygen and carbon dioxide and functions merely to
convey printed information, such æ information about the produce 44, to the
conwmer. It should be appreciated that the relative positions of the substrate 14, the
-
~ 2 1 4 ~ 9 2 0 ~ Vs~lo6c9 ,
:
: .
coa:eing 18 and~ e i~ laycr 74 ~e not importan~. The ink iayer 74 cauId be located
betweon t~e ~bstrate 14 and the coating 18 providod ~at coating 18 i~ parer
Similarly, th~ ink laycr 74 and ~ coasing 18 co~lld bc on oPposito
sidcs of ~e su~strate 14.
~n adh~sive 78 has been appliet to the side of the substrale 14
not con~g ehe iIlk layer 74. l he finished label adhesive
~icl~e~is "d" 8hould be abo~t 1.5 mil ~ .3 mil. 'rhe p~ fu~ction
of ~e adhe~ive 78 is to attach ~e substrate 14 to ~e packag~rlg
material 48. Any pressure-sensitiYe label adhosivc that is approvcd
for i~direct ~o~:~d c~ntaa c~n be used as the adhesive 78.
i~ shown in Fig. S, gc~ly ~e ~esive 78 is applied arol~nd
~e outer edbes of ~e substrate 14 so as to leave a region 82 on ~e
~ubs~te 14 ,~hat is not co~rcred wi~ adhesiYe 78. Since the 0~hesive
~ 78 are attachcd to thc packa~g snatenal 48, the part of thc
m~ 1~ tbat is "over" ~e ~l esive areas 78 is effectively
.,
~mpcnncablc ~o: oxygon .and carbon dio~cide. '1~s7 o~y thc part of thc
m~m~rane 10 th~ is. "ovcr" the ~egion 8~ is s "brca~able" ~rca through ;-~
which o~ty~ and carbon dio7dde can p~ss
to Figs. 1-5, ~c fimctio~ng ~f ~ pr~t in~fention ,~
20 ~ n now be ~:explai~ed. The co~ 18 is applied to the subsmte 14 to
~ . ,
rcssc ~e:~ pemleanco ~f substrato 14. In theory, for a subs~ate 14 .
ing a fi?~cd surf~ce area, ~e permeancc can be ~ecac~scd by aIly
Dmoont ~cn 0 and 100% by applyulg the coathg 18 to a~ ~ppropnatc
:: aN of the subs~a~e 14. It is thoupt that the coa~ng 18 reduces ; :
the pcrmeance of t~c subs~ c 14 by blocXing tllc pores th~t ex~t in ~;
tho substratc 14 th~t pro~ndc ~eways for the flow of oxygen or
carbon dioxido ~rough tho substrate 14.
By Ppb;D~: the c~g, 18 to the subs~ate 14 in a pa~
cove~s less ~an an entire su~face o~ t~e subslrate 14, t~e pcrmcsnce ~:;
- ~ 3 0 uf the su~s~ale 14 ~an be ~duced by a ~ uc less than 1~0%, For ~ ;
ex~mplc,~ in ~ig, 2, thc tar~c ~anglcs 24 cover approxi~ cly ~0% of ~ ~:
thc suri~ rea of dlc substrate 14 and thcrefore ~e expccted to --
` ~ ~ 214~920 (-
WO g4/1~40 PCTIUS93/10669
9 ' . ~;
decreæe the oxygen permeance by about 80%. Similarly, in Fig. 3, if ~`
the coating 18 covers about 50% of the surface area of the subs~ate
14, as represented by the dark area 32, then it is expected that the
oxygen permeance of the coated membrane shown in Fig. 3 would be
5 reduced by 50% compared to the permeance of the uncoated subs~ate 14.
In practice, a one-to-one relationship between the surface area
coated and the reduction in ef~ective permeance is not observed.
Generally, the observed reduction in effective permeance is somewhat
less than would be expected if the coa~ng was a perfectly effective
10 pore blocker. For exarnple, in Exarnple 1 (below), when a 50% pattern
- was used,-a 31% decrease in permeance was observed.
A major adva~age of the present invention is that by using
patterns of differing surface areas, a single substrate 14, having a
fixed oxygon pcrm~nce, can be used to prepare a variety of membranes
10 ~hat have different permeances after the coating 18 is applied in
diffcrent p~tterns and differcnt coating weights and formulations.
This is useful because in order to optimize the storage life of ~-`
different ~pes of produce 44, mernbr nes 10 of varying oxygen
permeance are required.
-; 20 In ~é preferred embodiment, the coating 18 is applied` to the ~;
substrate 14 using a flexographic process. In the flexographic
process, a flexible rubber or plastic plate ("Flexo Plate") is made
- having an image of the coating pattern which is to be transferred to
the substrate 14 (e.g. the patterns shown in Figs. 2 and 3). During
the convcrsion, the coating material is ~sfcrred from the raised
or image areas of the Flexo Plate to the substrate in the desired
pattern.
In order to obtain reproducible results from run to run using the
flexographic process, parameters such as the following should be
~' 30 controlled (the listed parameter values were selected as optimal for
the particular flexographic system used with the present invention):
1. The ac~ual temperatures of the drier and a&esive should be
~ . .
W~ 2 1 ~ 9 9 2 0
'~
mai~t~ined at a constant value (Inlc d~ying - 1~0 aF; ~ iv~ pan
tempe~e - 340 F~; 2. l~e viswsity of the coaffn~ ~hould be
m~i~inod at a CoD~t v~uc ~gcnerall~ about 200-250 cp); 3. T~e
Flcxo Plate to ~ub~ra~ce pressure should bo u~fon~ a~d ~e ~exo
S Pla~e shwlt be clea~ed ~odic~lly during thc t~t; 4. The run specd
should bc m~ntained at a const~nt ~alue (generally about 40
ftJ~); and ~. The ~nalox roll s}~oult ~e cleaned periodic~lly
d~t~. thc run - typically, about cvery 1000 impressions (a 300 lirle
~nalox roll ~n~ a doctor bla~e bas be~ usod for all coa~g mns).
While tl~e flexographt& process is ~e pre~tly pr~ferred mcthod
of p~oduclng: the membr~o~ 10, it ~hould be app~ ued that any
mcthod of ia~plying ~ coa~ng ~ a subst~atc could be uscd, including
rotograwre pr~csses, . le~er press prwesscs and ro~ary siLkscreen
proccsses.
E~LE I
~A rolI~o~ lypopylen~; f~m o~ om ~uk$ ~nc., a
~illed u~lly ori~d polyprcpylcnc film ha~ring ~n oxygen
p~co of ~r S65,000 c:c/100 1~2-a~nospber~day, was,loadcd onto thc
- ~pri~ting ~pr~ thc~ ~followi~g opua~ons were performcd o~ thc p~ess: 1. An
~:~ 20: ~1ic~ co~y r~JoNGyR~L 7~F), :ha~ a pr~p~ chomical composi~n~ wa~
to ~ (a; copolymor su~to), using ~ fl~c plate; 2. Ge~phics
u~; were~pdited~ovor tl~ ylic a~bn8; 3. l~e ~ive wasi p~n-~pplicd
t o tbc; ~b~c suffl~sc of ;~e: w~; 4. The co~gs we~e d~ied i~L ~ ovcn ~t l S0
degrees F;:~ S.~ ~ tQ the de~ sba~. T~is proe
: - -2S r~t a rr~ of tirnes usiing flexo6r-phio plates contE~i~g pattesDs for applying
*Ic acrylic coat~ig to 25%, 50%, 75%, ~ d 100% ol:` ~e ~urface area of ~he
- ~ w~ee la~1. .~hc pe~n~ of ~c ~ra~us;l~bols w~ e an oxygcn
. pm~ce te~ter and thc follow~g data were o~tai~d (pem~nco ~aluoe aro in ur
:: of cc/100 i~nospb~day):
- - :30
, ,
, "
i// ~: :
~ w0 94/12040 2 1 4 9 3 2 0r ,~,~,5
I
Sample Permeance Range (x ¦ Permeance j Average %
1000) (mean ~td) (x Perm. Red.
l 1000) ,
Unconverted Fi~n 542-573 565 +13
_
Converted Fi~n 517-540 529 +10 6%
25% Coatmg 428-480 461 _24 18%
Coverage I
50% Coating 354-432 ` 388 +38 ~ 31o
Coverage I
75% CoatIng 265-394 336 +49 41% ~;
l Coverage l
- 10 90% Coatmg 63-113 78 +~3 86%
Coverage ¦
100% CoatLng 12-62 44 +20 92% ~ -
Coverage `
. . . ~ `' ' :
15 * In UDitS of cc/100 in2-atm-day.
: T~BLE 1.
E~AI~PLE 2
A roll of microporous polypropylene fi~n obtained from Hercules, lnc., a
calcium carbonate-filled uniaxially oriented polypropylene film (a copolymer
substrate) having an oxygen pennen~ce of approxhn~ly 477,000 cc/lOO i*-
atmosphen-day, was con~rted into acrylic-coated (JONCYRYL 74F) membrane
làbels as descnbed in Example 1. However, the viscosity of ~o coating was variedas indicated in Table 2 by changing the ratio of acrylic emulsion to water in the
coating mixture.
~xami~on of the data in Table 2 shows that the average reduction in
permeance is depeindent on the viscosity of the coating 18 so that this parameter may
, - 30 be controlled in order to achieve reproduci~le results. -~
~ ~ .
21~9920
~ PCT~Sg311~69
. .:
S~mplc ~ I =~c; Avcr~ge % : ~:
1~) - (me~ ~ (x P~ .
_ . _ _ .
Uncon~erted Pilm 45S-498 477 ~19 _ ~:
. ~_ _ ,. ,:
SO% C~a~ng. 263-329 ~99 ~.? 37% . ..
Cov~rage; .
~iscosi~ ~ ~0- .
~50 cp ~ ~, :
SOYo Coating; lsl-æo 210 ~IS 56% .
Covc~gc; ~
viscosi~ ~ 400 cp :
_ ,,
75% C~a~in~ 120-lgS IS8 +'~? 67~/o .~;
C~over~ge; ~;
. V~sity-2~0- I _
7S.~o :C:oating 17~-218 196 ~IS sgO/~ i~
CoY~; ~ ~ : ;-~
Vi~ =390-cp ~ ~ . .~
~: _,,.,.......... ,.. " __~ '"''~'
- In uDits~of ec1100 ir~ tm~y.
- : TABLE 2.
EXA~D?LE 3
A rc~l1 o mic opo-ous polypropyl~e- film obtaincd ~ H~es, Ino., ~
calcium ~n~filled ~i~ially onc~tod polypropyl~n~ f;lm (a copolymer
~25 w~c) }lavi~ an o~gen parne~e of appro~um~eiy S67,000 ccJ1
y~ was lo~ded o~$o a Dilu~n coit~ ~d.thc follo~ op~ations w~
- pe~med i~l succossion on thc coater: (l) an a~ylic coatin~ ), ha~nng a
solids content ~f 2s%, w~ appliea to ~he susfa~e of thc film substrak us~ a
~ai~licoid ~r,¢~cylind (180 cellslline~ i~ch), ~2);~e film w~ pas~ rou~
: 8 140 dcgrccs F! ovcn at a speed of 4~ ft/m~ to try thc co~ting, ~sd ~3) ~e coatcd
film wa~ ODtO a takc up roll. 'l his proc~s was repcated vnth a sccond roll
~:: of ~rnicroporou~ film having ~n oxygen pe~ncance of 548,000 ccl100 in~ mospherc-
- ~:: day.
': -
2l4992d- '
WO g4112040 PCT/US93110669
13
The data in Table 3 shows that the gravure prLrlting method reduced the ~-
permeance of the films by approximately 41 to 48 percent.
¦ Film Sam~les Uncoated Film Gravure-Coatod I Avera~e Perm.
Penneance (x 1000) Film Permeance Red.
(x 1000) -~
I (mean i std)
6-175-01-00640- 567 ~ 294.+ 39 48.2%
0608-58 _
6-175-01-00640- 548 323 i 53 41.1% -
0608-64
* In ul~its of cc/100 in2-atm-day.
- 10 , . .
TABLE 3.
It should be noted that, while the conversion process of the present invention -
is~described as a s~uence of applying~coating layers, the order of applying the layers
is ~unimportant. It should also be noted that typically each layer must be allowed to : -~
dry beforé;tbe ~next layer is apphed. . ~ :-
~ present~invenbon has been particularly shown and descnbed with respect
to certs~n~prcfared enibodimel1ts of features thereof. However, it should be readily
apparent ~o those of ordinary skill in the art ~t vanous changos and modifications
- in form and~details may be; ~made without depar~ing from the spirit and scope of the
20~ ~ invention as set forth ~ the app~nded claims.
~: ,.
,:
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