Note: Descriptions are shown in the official language in which they were submitted.
~ ~2~764
1 ¦ BACICGROUND
3 ¦ This invention relates to a method of detecting
4 ¦ breaks in heat seals between paper and plastic, especially
5 ¦ in sterile packages and a packa~e wherein the ~aDer member -`~
6 ¦ is provided with a portion which can be seParated from the
7 ¦ package ~7hich carries indicia that changes color upon
8 ¦ sterilization.
9 ¦ Sterilizable packages or pouches made by margin-
10 ¦ ally heat sealing a clear plastic laminate to surgical
11 1 grade kraft paper or the like have come into widespread
12 1 use. The ~aper portion of such packages is designed to be
13 1 sufficiently porous to permit gas or steam sterilization
14 ¦ but is impervious to bacteria. The plastic laminate is heat
15 ¦ sealable to the paper, stable under sterilization conditions,
16 ¦ imvervious to bacteria and permits visual identification of
17 ¦ the package contents.
1~ ¦ Such packages are used for medical implements
19 ¦ that must be sterlle prior to use. The manufacture or
20 ¦ user (such as a hospital or clinic) of such medical im~le-
21 ¦ ments is su~plied with a ~ackage heat sealed around three
22 ¦ sides by the packa~e manufacturer. The medical implement
23 ¦ ls then pl.acecl in the package anc.l the Eourth sicle is heat
2~ ¦ sealed to complete the marginal seal between the ~aper and
25 ¦ the plast:ic.
26 Alter sterlli~ation, either by exposure to ethylene
27 oxide gas or by steam autoclaving, by the medical implement
28 manufacturer or by the hospital or clinic, the package and
29 its sterile contents can be stored for indefinite ~eriods
of time in a sterile condition.
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1 To determine if a sealecl package has been subjected
2 to sterilization, it has been cornmon practice to employ
3 indicator inks that change color upon gas or steam sterillza-
4 tion and these indicator inl~s are typically printed on the
exterior and/or interior of the paper member oE the
6 sterilizable package.
7 Prior to use, for examPle in an operating room,
3 the inclicator ink is inspected to make sure the package had
9 been properly sterilized and the marginal heat seal o~ the
vackage is visually inspected in an effort to detect whether
11 or not the initial heat seal is adequate or whether or not
12 there are any subsequent breaks or ruptures in the heat seal,
13 for example by accldental tampering with -the package after
1~ sterili.zation or by shifting of the package contents in such
a way that the heat seal becomes broken or ruptured.
16 Sterilization pouches are conventionall~y made of
17 clear, colorless plastic film heat sealed to white paper.
18 This combination of materials makes it extremely difficult,
19 if not impossihle, to visually determine if the initial
21 seal has subsequently been ruPt~lred or broken by tampering
or movement o:E the package contents.
22 To more readily ascertain the validity of the
23 initial heat seal, it has been proposed to lightly tint the
2~ plast-ic laminate member or to coat the paper member with a
~ :ligll~ly L:intecl heat seal. co,~tin~. This approach, however,
26 l~as 17eell far ~rorn satis~actory :in that it is no~ possibl.e
27 to read-LI.y ascertain ~y visual inspection the acle~uacy and
23 completeness oE the ini.tial heat sec11 between the plastic
29 film and the paper member. Moreover, there is no improve-
ment as compared to white paper and colorless plastic film
1121~764
1 s regards subsequent breaks or ruptur~s in the he.lt seal¦ :
2 between the p'lastic and the paDer due to tampering with the
3 ~acka~e or movement of the contents of the package. -
4 The main difEiculty with indicator inks printed
on either side of the paper member is that the package may be
6 subjected to sterilization conditions which are sufficient to
7 cause a color change in the indicator ink 'but insufficient to
actually sterllize the package contents. With an Lndicator
9 ink printed on the outside of the paper member the color
change will occur as soon as the indicator ink comes in con-
11 tact with steam or ethylene oxide gas and long before either
12 gas penetrates the paper member and sterilizes the Dackage
13 contents. Printing the indicator ink on the inside of the
14 paper member is an improvement but again the ethylene oxide
gas or steam in passing through the ~aper member comes in
16 contact wlth the indicator ink before reaching the package
17 contents. To cope with these problems manufacturers and
1'8 hospital~ have to follow sterilization procedures with a
19 built-in margin of safety to ensure tha~ the packa~e contents
are sterilizecl which means using high sterilization tem~eratures
21 over a sustained period oE time. Because oE these drawbacks
22 the indicator inlcs printed on the ins-ide or the outside of the
23 paDer member s:i~ply'say that the package has been put through
2~ ster:i.'l.:læcltlc)n bnt i~ :is leEt up to the techni.cian to ensure
2~ l:hc-t the correct sL:eriliæclti.on Droeedure has l~ecn observed to
26 e~'ecl:ivc!:ly ster:i.'l.i7.e t:lle pack~ge contcnt~.
27
29 .
~2~l7~
SUMMARY
The present invention provides a method and a
package, especially for sterilization pouches, which over~
comes the problems heretofore encountered in a simple,
effective and reliable fashion.
In accordance with one embodiment of the invention,
a method of detectin~ a break in a heat seal between a paper
member and a clear plastic member comprises providing a
paper member dyed a dark color, heat sealing the clear
plastic mer~ber directly to the dyed paper member in the
desired heat seaL area, thereafter visually examining the
heat seal to detect if the previously clear plastic member
takes on a translucent appearance in the area of the heat
seal which trarlslucent appearance provides a distinct
color contrast to detect a break in the heat seaL.
In accordance with a further ernbodiment of the
invention, a method of detecting a break in a heat seal
between a paper mernber and a clear plastic member in a
sterilizable package comirises providing a paper member
dyed a dark color which is sufficiently porous to permit
gas or steam sterilization but is impervious to bacteria,
heat sealing the clear plastic mernber directly to the
dyed paper member in the desired heat seal area, there-
after visually examin:i.ny the heat seal to detect i~ the
previously clear plastic mernber takes on a translucent
appearance ir- the area of the heat seal which translucent
appearance provides a distinct color contrast to detect a
break in the heat seal.
~he invention also provides a package which is
especially useful as a sterilization pouch wherein breaks
or ruptures in the heat seal due to either tampering with
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7~i4
the package of movernent of the package contents can be
readily detected visually by the user of the package con-
tents just prior to use.
In accordance with this aspect of the invention,
a package comprises a clear plastic member heat sealed
directly to a paper member dyed a dark color such that upon
breaking the heat seal the previously clear plastic member
takes on a translucent appearance in the area o~ the broken
seal which provides a distinct color contrast between the
break in the heat seal and the dark color of the paper in
any remainingheat sealed area.
The package may also include a member having the
desired indicator ink printed thereon which is inserted into
the package together with thelimplement to be steriliæed
prior to completing the marginal heat seal and subjecting the
package to sterilization. The indicia bearing member is
provided by printing the indicator inks on a portion of the
paper member of the package which extends beyond the area
enclosed by the marginal heat seal and making it readily
separable from the package. The indicia bearing portion
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1 ¦ inserted wi~h ~he item or imPlement to be sterilizecl in the
2 ¦ package, can be r?ositioned and oriented such that the
3 ¦ indicator ink Eaces the plastic member of the paclcage which
4 ¦ means that the sterilization gas will act on the indicator
5 ¦ ink to cause tlle color change at the same time or after
6 ¦ sterilization of the package contents has been accomplished.
7 This provicles a much better indication to the ultimate user
8 ¦ of the sterile item that it is, in Eact, in a ste~ile
9 ¦ conclition and not simply that the package has gone through a
10 ¦ sterilization procedure.
11 ¦ The method may also include providing a paper
12 1 member wherein the paper member has a portion extending beyond
13 ¦ the area to be enclosed by the heat seal when completed, said
1~ ¦ portion bearing indicia that changes color u~on sterilization,
inserting the item or implement to be sterilized into the
16 ¦ open-ended Package, separating the indicia bearing portion
17 ¦ from the package and inserting said separating portion into
18 ¦ the package with the indicia visible through the plastic
19 ¦ member, heat sealing the open end of the package and subject-
20 ¦ ing the sealed package to sterilization. Preferably the
21 ¦ indicia bearing portion is positioned between the item to be
22 ¦ sterili.zed and the plastic member with the indicia visible
23 1 throup,ll the plastic mernber. This, oE co-trse, (lepends on the
2~ ¦ nature and the .size o~ the i.tem or implement to be sterillzed.
25 1
26 ¦ n~SCRIPTION 0~ I'IIE DRAWI~GS
27 ~ _ _ ~ __ _ _ _ ___ _ __
8 1 The present invention will be more fully understood
29 ¦ :Erom the following descri~tion taken in conjunction with the
30 ¦ accompanying dra~ings wherein:
~ ~ ~2~76~
1 ¦ ~ig. 1 is a top plan view partly broken away of
2 ¦ a sterilization paclcage or pouch accorcling to the invention
3 1 marginally heat sealecl around three sides of the package
4 ¦ and shaded to indicate that the paper member is dark blue;
5 1 Fi.g. 2 is a top plan view of the sterilization
6 ¦ pouch shown in Fig. 1 heat sealed marginally along the
7 1 fourth side o:~ the package to enclose the package contents
8 ¦ which, i.n this instance, is a pair of scissors;
~ig. 3 is a sectional view taken along line 3-3
10 of Fig. l;
11 ~i~. 4 is a sectional view partly broken away
12 taken along line 4-~ of Fig. 2;
13 Fig 5 is a top plan view partly broken away of
14 a sterilization pouch according to the invention illustrating
various ways in which breaks or ruptures in a heat seal can
16 occur;
17 Fi.g. 6 is a bottom plan view of a sterilizable
18 pouch according to the invention from the pal?er side and
19 having triangular tear-ofE indicator T)ortion~s;
l~ig. 7 is a top plan view of the sterilization
2]. pouch of Fi~. 1 from the plastic side showi.ng the marginal
22 heat seal completed and one of the tri.angular shaped indicia
23 bearing portions separated from the package and inserted into
24 the paclcag~e :i.nterior with the package contents with the indicia
visible thrc)ll~h ttle plastic mernber.
26 l~:ig. 8 i.s a top Dl.an v:iew p.lrt:ly broken awa,v o~ an
27 alternate ernbocli.ment ol~ the present :inventlon o~ a steriliza-
28 t:iOIl l?ouch :Erom the plastic side; ancl
29 Fi.g 9 is a top plan view, partly brolcen away, of
a further embodiment o~ a sterilization pouch of the invention
also .Erom the pl.astic side thereoE.
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1 ¦ UESC~IPTION
2 I
3 ¦ The preferred embodiment o:E a sterilization pouch
4 ¦ shown in Fig. I and 2 of the drawin~ is shown to include a
5 ¦ paper member l0 having a dark coloration (in this illustra-
6 ¦ tion, dark blue) and a clear plastic laminate 12 which is
7 ¦ marginally heat sealed around three sides of the package in
¦ Fig. 1 and around the fourth side of the packa~e in Fig. 2
9 ¦ to complel:e the marginal heat seal 1~'~. The chevron con-
10 ¦ :Eiguration at the top of the package is used to facilitate
11 ¦ manual openin~ or peeling apart of the package to gain access
12 ¦ to the package contents which is .shown in Fi~. 2, for illus-
13 ¦ trative purposes, as a pair oE scissors 16.
14 ¦ The paper member 1~ can be conveniently dyed or
15 ¦ tinted the desired relatively dark color, for example dark
16 ¦ bluel dark green, dark red, dark brown, dark grey, or black.
17 ¦ Instead of dyeing or tinting the paper member 10, the paper
18 ¦ member can have a relatively dark coating applied thereto,
19 ¦ at least in the heat seal area. This can readily be accom-
20 ¦ plished by overprinting all or only the seal area of the
21 ¦ paper member 10 with a dark ink such as the dark colors
22 ¦ enumerated previously. The dye, tint or ink should be
23 1 selected so as to be stable under sterilization condi.tions.
2~ ¦ Readi.ly available surgical ~,rade IcraEt paper
25 ¦ tlclVing the cles:ired po-rosity char,tcteristics can he reaclily
2~ ¦ (Iyerl or overpr:inl~e~] to provide the desirecl relatively dark
27 ¦ coloratlotl Eor tlle p,lper member 10.
2~ ¦ 'l`he term "paper" as used herein also a~pl;.es to
29 synthetic or artificial paper materi,als made from plastic
~ibers and the like, as well as conventional paper products
1~21764
l ~ havi the necessary characteris~ic 5 for use in ~terilization
2 pouches. ~n example of synthetic paper is a spun boncded
3 polyelllyl.ene sold hy DuPont uncler the traclemark "TYVEK".
4 The l?lastic member 12 is ~referably a laminate
o.E a polyester, such as pol.yethylene terePhthalate sold
6 under the trademarlc "MYL~R", and a heat sealable thermo-
7 plastic materiaL such as polyethylene, polypropylene, ethylene
vinyl acetate, an ionomer such as ~uPont's "SURLYN", co-
9 polyme-rs and mixtures of the Eoregoing. The polyester layer
forms the exterior of the package and the heat sealable
11 thermoplastic material inter~aces with the paper member 10 :
12 and forms the marginal heat seal 14.
13 ¦ Heat sealing the plastic member 12 to the paper
14 member 10 around the margin of the t~ackage as sho~m in
Figs. 1 and 2 of the drawing can be accomDlished using
16 conventional heat sealing equipment and techniques. Generally,
17 the heat seal is made wide:enough to guarantee an adequate and
18 complete seal around the margin of the package initially
19 formed with a heat seal around the three sides wi.th the fourth
side comple~ed after the package contents are insertecl therein
21 as shown in Fig. 2. If desired, a number oE t~arallel spaced
22 apart seals can be effected in the area of the marginal heat
23 seal 14. This is co~nonly known in the indu.stry as a rih seal
2~ and is employecl to .imparl: acldi.tional. ~eel. strength to the heat
seal beLweell the pllstic member 12 and the paT~er member 10.
26 ~ccorcl:in~ to the invention, the pl.. lstic member 1227 c".~tlibil:s a re:Lcltive:Ly translucellt a~pear.].rlce wll:ich can be
28 clescribed as cloudy or milky as compared to the clear member
29 itse:LE, upon rupture or breaking of the heat seal area 14.
This cloudy or mill<y appearance is believed to result Erom
z~
1 e he.lt sealin~/ operation and only comes into being when
2 the heat seal is ruptured or broken. This phenomenon is
3 believed to result from a surface con:Eormation by the plastic
4 member l2 ~o ~-he surface of the paper mem~er 10. The paper
mc?ml~c?r 10 ustlally has a dull or matte fini.sh and this is
6 duplicatecl in the seal area of the film in a cloucly or milky
7 appearance upon rupture or breaking of the heat seal 14.
Fig. 5 o:E the dra~7ing ls intended to illustrate
9 how the present invention provides a visuaL contrast ~or
readily detecting breaks or ruptures in the hea~ seal between
11 the paper member ln and the plastic member 12, whether due to
12 part-ial opening of the package, either intentionally or
13 unintentionally, or b~ shiEting of the packa~e contents. In
14 Fig. 5 the plastic member 12 is shown ~ulled back and separated
from the chevron portion o the heat seal area 14. The left
16 side of the f-igure shows the cloudy or milky appearance 18
17 from the heat seal side of the plastic member 12, whereas the
18 right side of the figure shows the contrast that results from
19 the exterior side of the Plastic film 12. Note especially
the marked contrast of the broken hea~ seal area 18 with
21 respect to the dark coloration oE the paper member 10 itself
22 ancl the remainin~ sealed area 14. It should also be noted
23 t~hat the sealed area 14 has a glossy, clear a~pearance which
24 :Ls in contras~ to ~:he dul.:l or matte Einish appearance oE
tlle l~nper mc?mber l() t:hrough thc? p:Lnsl.i.c membc?r 12 outsicle of
26 thc~ se<l:l. area 1~l. 'rhis contrasl: can be use~cl to cletect voicls
27 or delr~(?cts i.n the herlt seals rrlclde l~y th~! packclp,e manuEacturer
28 and also the paclcager.
29 ~lso illustrated in Fi~. 5 is the visual contrast
that results when the package contents sllcll as the pointed
llZ17fi~
. ~ ,
1 end oE scissors 16 shifts and DierCeS or ruptures the heat
2 seal l~. As can be seen, this results in a readily discernible
3 translucent apPearance 18 which i.s in dist:inct color contrast
4 with the dark coloration oE the paper member 10 through the
plastic member 12 in the unsealed areas of the package and
6 is also in distinct color con~rast with the remaining heat
7 sealed area 14 which shows the coloratlon of the paper member 10
in a clear and glossy fashion. Thus, in the case o~ a dark .
9 blue paper member 10, the user of a sterilized package such as
showll in ~ig. 2 can readily determine by a simple visual
ll examination if the packa~,e, after sterilization, has been .
12 opened, either intentionall.y or unintentionally, that ls, by
13 pee].lng apart the two member 10 and ].2 or whether the package
14 contents, such as the sclssors 16 has shifted and ~ierced or
ruptured the heat seal 14. In either instance, the trans-
16 lucent portion 18 which has a cloudly or milky appearance
17 is in distinct color contrast with the dark coloration o~ the
18 paper member 10 itself, which in this case is dark blue, and
19 the remairl-ing heat sealed area which has a clear, dark blue
coLoration, but is glossy in appearance as compared to the
21 matte or dull finisil of the paper member 10 itselE outside
22 the seal area.
23 '!'he same, highly visual color contrast results from
2~ llnpart:ing l:o tlle paper mc!ml.)er 10 a rc-~lat:ivelY clark coloration
.s~.lcll as dnrlc bl.l.le., (.larlc precll, darlc recl, clarlc brown, darlc
26 f~rey, or bLa.ck.
27 l~eEerr:i.ng now to :Fif~9. ~ and 7 Ihe trianf~ular shaped
28 portions 20 extendin~.T beyond the inver~.ed V-end seal which is
29 beyond the area to be enclosed by the marginal heat seal 14
when comp]eted (F:ig. 7). As shown in ~ . 6, the paper 10
~ ~Z~ 4
1 ¦ may have a white area or block printed thereon so th~t
2 ¦ portions 20 can bear lndieia that changes eolor upon
3 ¦ steriliæation, one portion bearing indicia that changes
4 ¦ color upon steam sterilization ancl the other norti.on 20
5 ¦ indicia that changes color upon gas steriliY.ation such as
6 ¦ ethylene oxi.de gas. The indlcia whieh is commonly referred
7 ¦ to as indicator inks is ~enerally shown by the reference
8 ¦ numeral 22.
9 ¦ - Suitable indicator inks .for the indicia 22 are
10 ¦ any of the commercially available and commonly used indicator
11 inks for sterilization ~ouches. A typical indicator ink for
12 use with steam autoclaving is a chemically active ink that
13 changes from pink to dark brown during steam au~oclaving.
14 A typical indicator ink for use with ethylene oxide
sterilization is a chemically active ink that changes color
16 from light brown or tan to orange upon exposure to ethylene
17 oxide gas sterilization.
18 Steam autoclaving and ethylene oxide ~as are known
19 sterilizati,on techniques ancl the present inventi.on is well
adapted to these procedures.
21 An item to be sterilized such as the scissors 16
22 shown in Fi~. 7 is i.nserted through the open end of the pouch
23 shown in ~`ig. 6. Depending on the steri:lization procedure
2~ to be emr~loye(L, the technician separates the proper inclieia
bearing port:ion 20 each oE wh:ieh i.s attachecl to the paper
2G por~i.oll 'L0 a~- 25 and ~reellt: thereb~tween a~Long line 2~. The
27 technician or operator then lnserts the separated ~ortion 20
28 into the paclcage with ~he indicia 22 vlsible through the
29 ~lasti.c mernber 1.2 as shown in Fig. 7. The marginal heat
seal 14 is then completed and the paclcage is ready for
sterill~.ation.
Z~7~;4
1 During sterilization, the sterilizinp, medium, steam
2 I or ethylene oxicle ~,as, sterilizes the scissors 16 and at the
3 I s~me time or afterwards, reaches the indici.a 22 which then
4 undcrfroes the ;.nd:icated color chanc~,e to indicate ~hat the
packct~,e contents and not just the paclcage itself are sterile.
6 Depencling on the nature and size of the item or imp].ement to
7 be ster11ized, it is preferred to ~osi.tion the portion 20
8 ~ which is in~serted into the pouch between the item to be
9 I sterilized anti the p1astic member which ensures that the
10 ¦ sterilizatioTI meclium will not cause a color chancs,e in the
Il ¦ color sensit-ive indicia until after the sterilizing medium
12 ¦ has cont.actecl the item to be steri.lizecl. In any event, the
13 ¦ indicicl 20 must be v;.sible through the Plastic member 12 when
14 ¦ the porl:i.on 20 is separated ~Erom the packacs,e and inserted into
¦ the ilILerior thereof with the item to be sterilized.
16 ¦ The preferred embodiment shown in ~igs. 6 and 7 has
17 I a ~urther advantage in that sealed ~aclcages ready for
18 ¦ sterilization can be se~regated by t:he intended sterilization
19 ¦ proceclure to be emt~loyed l)y virtue of the Eact that one of
¦ the incliclcl-be~rin~, portions 30 is missin~ from either the
21 ¦ left or rl~.~,ht sicle of each ~sealed pouch when t:he po~lches are
22 I J.ined U!) and o-ri.ente(l l.n l,l~e s~ e cl-i.rccl,.ioll. TI1~JS~ :it :i.s easy
23 ¦ Lo delect :if a paclc~ ,e (les:i~rn.lte(] -Enr ~ste.:lm ste-ril:ization has
2~i ¦ beconle nli.xecI ln w;.th paclca~,es cIesi~nated for etllylene oxide
25 ¦ s~eri.lizat:LolI.
2G ~ l~ .s .~ an(:l 9 show alternate embo(I-i.ments of the
27 ¦ presetlt inveI-lt:ion. In ]i.~ , the indi.cict beari.n~ Porti.ons 20
28 1 are clef:ine(I vi.a perforate(I line~s 2~ at the bottom or open end
29 ¦ of the sterilization Pouch. A:Eter the item to be sterilized
30 ¦ is inserted into the pouch under plastic member 12, the
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~
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l ¦ clesirecl portion 20 of the paper member 10 is separated and
2 ¦ inserted into the poucll with the item to be steri.lized with
3 ¦ the indicia 22 visible throug} the plastic member 12. The
4 ¦ transverse heat seal across the bottom shown by dash lines
5 ¦ is then macle to complete the marginal heat seal 14.
6 ¦ The embodiment shown in Fig. 9 is similar to the
7 ¦ embodiment shown in Fig. 6 except the end seal opposite thè
¦ open end of the pouch is a straight transverse seal and the '
9 1 ,portion of the paper member 10 extending beyond the area to
lO ¦ be enclosed by tlle marginal heat seal 14 is divided into two
ll ¦ rectangular indicia beari.ng portions 20 via perforated llne 24.
12 1 The steriliæation pouch of the invention will
13 ¦ typlcally bear other indicia as shown in Fip,. 6, for example
14 ¦ on the exterior side of the paper member 12, nreferably in a
15 ¦ whitened area, to designate for exam~le the package contents,
16 ¦ the sterilization date, the expiration date and the like.
7 1 The color sensitive indicia 22 is commonly printed
19 o the paDer member 0 using known techniques.
22 ;
26
27
29
