US 3547257 A
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United States Patent 72] Inventor James L. Armentrout Pasadena, Calif.  Appl. No. 699,608  Filed Jan. 22,1968  Patented Dec. 15, 1970  Assignee American Hospital Supply Corporation Evanston, Ill. a corporation of Illinois  PACKAGE FOR STERILE ARTICLE 13 Claims, 7 Drawing Figs.
 U.S. Cl 206/632; 229/66, 229/48  1nt.Cl ..A61b 19/02  Field of Search... 206/632, 63.3, 63.4, 63.5, 43; 264/36; 161/169, Polythone; 229/48T, Vent, 66, 85, 51W.B.
 References Cited UNITED STATES PATENTS 3,081,519 3/1963 Blades et al 161/169UX 3,069,273 12/1962 Wayne 229/51W.B.X
3,256,981 6/1966 Kurtz 229/51W.B.X
3,278,109 10/1966 Salway 229/51W.B
3,148,101 9/1964 Al1man,.lr. et al .,161/(P0lythone) FOREIGN PATENTS 1,308,743 10/1962 France 206/633 Primary Examiner-Joseph R. Leclair Assistant Examiner-John M. Caskie Altorneys-Larry N. Barger and Robert T. Merrick PATENTEU mam 51910 3541257 SHEET 1 [1F 2 INV/iN'lUR. JAMES 1.. ARMENTROUT PATENTED 051:1 5 I970 sum 2 or 2 PACKAGE FOR STERILE ARTICLE This invention relates to a package for containing medical or hospital supplies and keeping them sterile until use.
This invention includes a unique sterilization vent structure on a plastic envelope encasing a sterile product. In one embodiment of the invention this vent structure also provides a way of opening the package.
Vents on plastic envelopes have previouslybeen proposed. One such vent is a porous paper patch adhesively secured to a plastic bag or envelope. This paper patch filtered out bacteria and allowed sterilizing gases such as ethylene oxide to enter and exit the package. However, adhesiv'ely secured paper patches can come loose in shipping and abrade or tear under some conditions to jeopardize the sterilityv of the encased product. With most adhesives, such a patch can be pulled loose from a polyolefin envelope and subsequently replaced without showing evidence of tampering with the package. Also, polyolefin film is very slick and it is difficult to get an adhesive tobond to the film. It is therefore an object of this invention to provide a vent construction for-a plastic envelope which does not have these defects.
My invention includes a nonporous polyolefin plastic envelope or bag encasing a sterile product. This envelope has a vent opening therein and has a porous nonwoven polyolefin plastic sheet member integrally fused to the envelope to close the vent opening. Bacteria are filtered out by the porous sheet member, but sterilizing gases such as ethylene oxide can enter and exit through the porous sheet memben'Since the envelope and the porous sheet member are both polyolefin plastics, they can be fused together'by heat to form an integral closed protective sheath around the sterile product. No adhesive is needed or desired.
l have also discovered that when theporous sheet member is folded over and sealed to the envelope to close an open mouth at one end of the envelope, this construction provides a package which is easy to open for removal of the sterile product.
Perhaps this invention can be better reference to the attached drawings, in which:
FIG. 1 is a top plan view of a package showing the porous sheet member at one end of the envelope;
FIG. 2 is a cross-sectional view taken along line 2-2 of FIG.
understood with FIG. 3 is an enlarged fragmentary 1 cross-sectional view taken along line 3-3 of FIG. 1-;
FIG. 4 is an enlarged fragmentary cross sectional view taken along line 44 of FIG. 1;
FIG. 5 is a top plan view of another package with the porous sheet member located at a center portion of the envelope;
FIG. 6 is a cross-sectional view taken along line 6-6 of FIG. 5; and a FIG. 7 is an enlarged member.
With reference to the drawings, one embodiment of my invention is shown in FIGS. 14 and another embodiment is shown in FIGS. 5-6.
fragmentary view of the porous sheet The structure of sheet member 7 includes a multitude of very fine continuous polyolefin filaments intertwined into a matte 11, which matte resembles a mass of matted hair under a microscope. As shown in FIG. 7, these filaments are fused together where they cross by the closely controlled application of heat and pressure to provide a sheet member which has interstices between its filaments. This sheet member is entirely of polyolefin and I have found it heat seals readily to the polyolefin envelope. The sheet member 7 looks like opaque paper but unlike paper it needs no adhesive'for bonding to a polyolefin envelope. A material very suitable for sheet member 7 is a spun bonded nonwoven polyolefinmade by Du Pont Chemical Company under the trademark Tyvek.
When sheet member 7 is heat sealedto envelope 2, I have found that the intertwined filaments at heat-seal line 8 melt and flow into a fused polyolefin joint as in FIG. 3. This heat seal destroys the porosity of the sheet in the area of the heat seal, and also in this area changes the appearance of the sheet member from opaque to translucent, thus giving a visual indication of the location continuity and effectiveness of the seal line 8.
Unexpectedly, I have also found that the package is easily openable by tearing along seal line 8. This is unexpected because a heat seal between layers of nonporous polyolefin I envelope material does not necessarily tear easily. Instead it In FIG. 1, a tear-open package completely encases a sterile product 1 which might be a box containing all the necessary medical equipment. for a spinal anesthesia, a urethral catheterization or other medical procedure. This package ineludes an envelope 2 of nonporous polyolefin sheet material sealed into a rectangular envelope by heat seals 3, 4 and 5 along three edges. Along a fourth edge' is .an open mouth 6 woven, porous polyolefin sheet member 7 sealed to the nonporous polyolefin envelope 2 makes a smooth tear alonga weakened edge of seal line 8, because the tensile strength is weakest at the seal line 8. Seal line 8 has substantial width, but the tear line is always along edge 12 of the seal line so the seal line itself stays with sheet member 7. This can perhaps be explained because the porous sheet member 7with its extruded filaments is much more resistant to tearing and stretches substantially less than the envelope material which might be of polyethylene sheet, with low density polyethylene sheet preferred.
The reason why the tear-open" feature of the invention works so well is because the sheet member 7 of Tyvek (Du- Pont trademark) has substantially no stretch and the nonporous polyolefin sheet of envelope 2 stretches a substantial amount adjacent seal line 8 when pulled apart. Thus, nonstretching sheet member 7 can concentrate tearing forces at edge 12 of seal line 8 facing the envelope 2.
To prove out this point, a series of dumbbell-shaped samples for pull tests were prepared. These samples had one end portion of Tyvek and the other end portion -of nonporous polyethylene with each end portion sealed to the other along a seal line 8. This is a very long stretch considering that most of I its stretch occurred in the necked-down portion of the dumbbell half which was approximately l inch in length. Thus, it is safe to say that the nonporous polyethylene sheet stretched in excess of 100 percent immediately adjacent seal line 8 and the Tyvek had substantially no stretch immediately adjacent seal line 8.
The preferred embodiment of my invention is shown in FIGS. 1-4 with the porous sheet member 7 sealed across one end of envelope 2 to provide a tear open package. However, it is also possible to have a vent patch of the porous polyolefin sheet member 16 fused to a middle portion of envelope 14 at seal line 17 as in FIGS. 5 and 6. This construction also provides an entrance for sterilizing gases through vent opening 15 for gas sterilization of product 13.
g The envelopes and 14, as well as the porous sheet membets 7 and 16, are of polyolefin plastic material such as polyethylene, polypropylene, copolymers, or mixtures of polyethylene and polypropylene. Extremely good results have "skilled in the art can make certain modifications to these embodiments without department from the spirit and scope of :this invention.
1. in the combination of a sterile product, and a tear-open package completely encasing said sterile product, an improve- 'ment in said package comprising: a polyolefin envelope having "an opening through which the sterile product can pass; and a porous polyolefin sheet member that is pervious to sterilizing gases but impervious to bacteria, which porous sheet member spans said opening and is integrally fused to the envelope along a seal line surrounding said opening, said package being lopenable by tearing the envelope and sheet member apart along said seal line, said opening extending across one end of I'the envelope, the envelope having opposed facing walls and the porous sheet member having a folded configuration which has two opposed facing portions that are fused respectively to the opposed facing walls of the envelope;
2. The improvement as set forth in claim 1 wherein the en- ,velope and porous sheet member are of a polyolefin selected from the group consisting of polyethylene, polypropylene, .copolyrners of polyethylene and polypropylene, and mixtures of polyethylene and polypropylene.
3. The improvement as set forth in claim 1 wherein the envelope and porous sheet member are of the same polyolefin.
,4. The improvement as set forth in claim 3 wherein the envelope and porous sheet member are both polyethylene.
5. The improvement as set forth in claim 1 wherein the porous sheet member is nonwoven and paperlike and has continuous polyolefin filaments intertwined into a matte with the filaments fused together where they cross each other.
6. The improvement as set forth in claim 1 wherein the ten- .sile strength at break is substantially less at the seal line than for either the envelope material alone or the porous polyolefin sheet material alone.
7. The improvement as set forth in claim 6 wherein the porous polyolefin sheet has substantially no stretch immediately adjacent the seal line when the package is torn apart at the seal line.
8. The improvement as set forth in claim 6 wherein the polyolefin envelope has a substantial amount of stretch immediately adjacent the seal line when the package is torn apart at the seal line.
9. The improvement as set forth in claim 8 wherein the polyolefin envelope stretches in excess of 100 percent im mediately adjacent the seal line when the package is torn apart at the seal line.
10. The improvement as set forth in claim 1 wherein the seal line has substantial width and the package ruptures along an edge of this transverse seal line, said seal line itself remaining with the porous sheet member when the porous sheet member and envelope are manually pulled apart.
11. The combination of a sterile product and a tear-open package completely encasing said sterile product, said package comprising: a rectangular polyethylene envelope with a front wall and a rear wall joined together along three edges. said envelope having an open mouth along its fourth edge through which the sterile product can pass; and a porous, nonwoven paperlike sheet member that has continuous polyethylene filaments intertwined into a matte and fused together where these filaments cross each other, said sheet member being pervious to sterilizing gases but impervious to bacteria, which sheet member has a folded configuration including front and rear facing portions which are integrally fused respectively to the fron and rear walls of said envelope along a transverse seal line surrounding the opening in said envelope, said seal line formed by the fused joint between the porous sheet member and the envelope being rupturable by manually pulling the porous sheet member and envelope apart to open said package.
12. The combination as set forth in claim ll wherein the seal line has substantial width and the package upon opening ruptures along an edge of the transverse seal line with the seal line itself remaining with the porous sheet member.
13. The combination as set forth in claim 11 wherein the porous sheet member is opaque and the seal line is translucent, thus showing the precise location of the seal line for opening