WO1996017792A1 - Structure d'ouverture d'emballage polymere - Google Patents

Structure d'ouverture d'emballage polymere Download PDF

Info

Publication number
WO1996017792A1
WO1996017792A1 PCT/US1995/015778 US9515778W WO9617792A1 WO 1996017792 A1 WO1996017792 A1 WO 1996017792A1 US 9515778 W US9515778 W US 9515778W WO 9617792 A1 WO9617792 A1 WO 9617792A1
Authority
WO
WIPO (PCT)
Prior art keywords
polymer
opening
sheet
ribs
tear strength
Prior art date
Application number
PCT/US1995/015778
Other languages
English (en)
Inventor
Robert William Hinley
Original Assignee
Rexam Medical Packaging, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Rexam Medical Packaging, Inc. filed Critical Rexam Medical Packaging, Inc.
Priority to AU45090/96A priority Critical patent/AU4509096A/en
Publication of WO1996017792A1 publication Critical patent/WO1996017792A1/fr

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D75/00—Packages comprising articles or materials partially or wholly enclosed in strips, sheets, blanks, tubes, or webs of flexible sheet material, e.g. in folded wrappers
    • B65D75/52—Details
    • B65D75/58—Opening or contents-removing devices added or incorporated during package manufacture
    • B65D75/5805—Opening or contents-removing devices added or incorporated during package manufacture for tearing a side strip parallel and next to the edge, e.g. by means of a line of weakness
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
    • B29C48/07—Flat, e.g. panels
    • B29C48/08—Flat, e.g. panels flexible, e.g. films
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/001—Combinations of extrusion moulding with other shaping operations
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
    • B29C48/001—Combinations of extrusion moulding with other shaping operations
    • B29C48/0018—Combinations of extrusion moulding with other shaping operations combined with shaping by orienting, stretching or shrinking, e.g. film blowing

Definitions

  • the present invention relates to opening structures for sealed packages, and in particular relates to an opening structure for a sealed package formed of a polymer, and for which sterile conditions must be initiated and maintained until the bag is opened.
  • thermoplastic polymers particularly polyolefins
  • Thermoplastic polymers can be subjected to commonly-used sterilization techniques, are generally very durable, provide a biological barrier to prevent instruments after sterilization, and can often be made into transparent films that permit the contents of the bags to remain visible, particularly to the personnel that are going to use them.
  • the purpose of packaging medical instruments and supplies in sterile bags is that of later using them in medical procedures.
  • the bags must be relatively easy to open, in terms of both speed and convenience, by medical personnel during the course of medical procedures.
  • One typical method of providing an opening system for such a bag is to provide a score line across the bag, i.e., a line of weakness in the polymer.
  • a score line represents an attempt to give medical personnel a means for easily opening the bag by pulling on opposite sides of the score line.
  • Score lines must meet conflicting standards. They need to be weak enough to allow the package to be opened easily when desired, but strong enough to prevent the bag from opening unintentionally during normal handling. Thus, the task of producing a successful score line is one of making a highly predictable strength value. As might be expected, because of the stringent requirements of medical packaging, attempting to get such a perfect score line can tend to result in a fair amount of manufacturing waste. Forming score lines of a desired strength has also been made more difficult by the generally increasing strength of the polymers used to form the bags. Additionally, score lines are particularly disadvantageous for bags that contain sterile liquids because of their potential for undesired and unintentional leakage.
  • peelable header Another typical opening structure for sterile packaging is referred to as a "peelable header.”
  • a structure is formed of a portion of paper or other similar material that is welded over an opening in the polymer that forms the remainder of the sterile package.
  • peelable headers tend to raise their cost and manufacturing complexity. Additionally, peelable headers tend to be vulnerable to premature--i.e. , undesired--opening during sterilization and handling.
  • the strength of polymers used to form sterile packages has continued to increase.
  • the increased polymer strength offers a number of advantages in the resulting package: larger kits can be packaged, and shorter, but more severe, sterilization techniques can be used.
  • the stronger polymers also provide higher resistance to cuts, punctures, and overall impact. Nevertheless, the stronger polymers are more difficult to open, and balancing structural integrity against ease of opening becomes more difficult.
  • an object of the present invention to provide an opening structure for a polymeric package which provides ease of opening when opening is desired, but which has a better strength and integrity in keeping the package closed during manufacture, packaging, sterilization, storage, and handling.
  • the invention meets this object with an opening structure for a polymeric sheet material such as those used to form sealed packages, including sealed sterile packages for medical applications.
  • the opening structure comprises a polymer sheet formed of a plurality of linearly extending adjacent ribs in which the polymer is highly oriented along the linear direction defined by the ribs.
  • the ribs include portions that are generally weaker in tear strength along the direction of orientation than the remaining portions of the ribs to thereby form a more easily tearable, and thus more easily opened, portion of the polymer sheet.
  • the opening feature can be used in the absence of other mechanical features such as scoring that would otherwise weaken the mechanical integrity of the sheet.
  • the invention comprises an opening structure for a polymeric sheet material such as those used to form sealed packages, in which the opening structure comprises a first polymer sheet having an opening precursor structure; and a second polymer sheet superimposed on the first polymer sheet and covering the opening precursor structure.
  • the second sheet has a tear strength that is greater than the tear strength of the opening precursor structure and less than the tear strength of the remainder of the first polymer sheet.
  • Figure 1 is a perspective view of an opened bag with an opening structure according to the present invention
  • Figure 2 is a perspective view of a sealed bag with the opening feature of the present inven ion;
  • Figure 3 is a view showing the manner in which the opening features works;
  • Figure 4 is a cross-sectional view taken along lines 4-4 of Figure 1; and Figure 5 is a view of the interior face of a polymer sheet with an opening structure according to a further embodiment of the invention.
  • the present invention is an opening structure for a polymeric sheet material such as those used to form sealed packages, including sealed sterile packages for medical applications.
  • the opening structure is usually incorporated in conjunction with a bag structure, although it will be understood that the invention is not limited to bags per se.
  • Figures 1 and 2 illustrate perspective views of a bag broadly designated at 10 that incorporates the opening structure according to the invention.
  • the bag is formed of two substantially transparent polymer sheet portions 11 and 12. Although illustrated as being transparent, such is a preference rather than a requirement.
  • the sheets are preferably translucent or opaque as may be desired or necessary for a given application. It will thus be understood that the transparency or opacity of the sheets is unrelated to the invention or to the scope of the claims herein.
  • the bag 10 also includes four edges 13, 14,
  • the opening structure is a polymer sheet broadly designated in the drawings at 17.
  • the sheet is formed of a plurality of linearly extending adjacent ribs 20 ( Figure 4) in which the polymer is highly oriented along the linear direction defined by the ribs.
  • the ribs include portions that are generally weaker in tear strength along the direction of orientation than are the remaining portions of the ribs 20 to thereby form a more easily tearable, and thus more easily opened, portion of the polymer sheet.
  • the weaker portions are the thin portions between the ribs 20.
  • orientation is used herein in its usual sense to express the degree of parallelism of the chain molecules that form the polymer. The more parallel the molecules, the more highly oriented the polymer is said to be.
  • the drawings illustrate the ribbed polymer sheet as a substantially planar strip 17, but in other embodiments, the ribbed polymer sheet can comprise a tube.
  • the ribbed polymer strip 17 can be incorporated into a side seal bag format or a bottom seal bag format as may be desired or necessary.
  • the ribbed polymer sheet is preferably formed of a thermoplastic polymer, as these tend to be the most easily oriented and thus most useful for the present invention.
  • a thermoplastic polymer for medical applications, where strength and sterilizability are required, polyolefins (e.g., polyethylene, polystyrene, polypropylene) are often preferred, along with various ionomers.
  • the polymer can comprise nylon, ethylene vinyl alcohol (EVOH) polymers and other polymers with similar or related properties. It will be understood that if desired, the entire bag 10 could be formed of the ribbed sheet 17.
  • non-ribbed surface portions are useful for printing, labeling, and overall visibility, particularly when the polymer sheets 11 and 12 are transparent.
  • the non-ribbed sheet portions tend to be more amenable to the blowing steps often used in the manufacture of polymer tubes and bags. Stated differently, the blow-up ratios of the ribbed portions tend to be lower than those of the non- ribbed portions.
  • the opening structure 17 can be welded to a transparent sheet of thermoplastic polymer, as illustrated by the weld lines 21 and 22 in Figure 3.
  • the opening structure 17 can comprise a single sheet that includes both ribbed portions and non-ribbed portions.
  • the ribbed sheet 17 is welded over a portion of the sheet material 11 that forms the overall bag 10.
  • at least one of the polymer sheets 11 or 12 can comprise a score line (not shown) , and the ribbed polymer strip 17 can cover the score line, a perforated line, or even a slit. Because the ribbed polymer strip 17 is welded to the sheets 11 and 12, the score line is sealed from exposure, and thus can be formed to be easily tearable . without sacrificing the overall integrity of the bag 10 and without concern for opening unintentionally.
  • the sheet 11 or 12 can be replaced by the strip 17 for a portion of the bag equivalent to the width of the strip.
  • the strip 17 is preferably welded to the sheets 11 and 12.
  • the ribbed polymer strip 17 can be integral with the remainder of one or both of the polymer sheets 11 and 12.
  • the opening structure can be used in the absence of other mechanical features such as scoring, perforations, or slits, that could otherwise weaken the mechanical integrity of the sheets 11 and 12 and the overall bag 10.
  • the term "welded" refers to any appropriate method of securing polymer sheets to one another and can include heat sealing, radio frequency sealing, and other techniques that will provide the appropriate integrity required for such a sterilizable structure.
  • the polymer sheets 11 and 12 are transparent and form an overall transparent bag structure.
  • the invention comprises a method of forming an opening structure for a polymeric sheet such as the sheets used to form sealed packages including sealed sterile packages for medical applications such as the bag 10 illustrated in the drawings. The method comprises extruding a fluid polymer through a plurality of adjacent capillaries that provide sufficient drag flow to the fluid polymer to force the fluid polymer into linear orientation along the direction of extrusion. Thereafter, the extruded liquid polymer is solidified quickly enough to prevent the extruded liquid polymer from returning to a more random orientation during solidification.
  • the term "extrusion” is used in its usual sense; i.e., a processing operation in which the material--here the polymer--is forced through a forming die, followed by some sort of cooling or other hardening.
  • polymers When polymers are extruded, they can be solidified in several fashions.
  • the usual techniques include cooling a liquid polymer to a temperature lower than its melting point; e.g. by contact with air, water, or a cool- surface such as a chill roller.
  • the step of extruding the fluid polymer through the plurality of adjacent capillaries comprises extruding the polymer through adjacent capillaries that together form a substantially planar opening, or alternatively a substantially circular opening.
  • the step of solidifying the extruded liquid polymer comprises solidifying the liquid polymer either in the substantially planar shape of the opening, or the substantially circular shape of the opening.
  • the solidifying step is preferably a conventional cooling step such as exposure to air, a water bath, or a chill roller.
  • the step of extruding the polymer preferably comprises extruding a thermoplastic polymer selected from the group consisting of polyethylene, polypropylene, other polyolefins, and polystyrene.
  • thermoplastic is used in its usual sense herein and refers to those polymers that soften when exposed to heat, and return to their original condition when cooled to room temperature. Natural thermoplastic substances include rubber and certain waxes, but the term is more typically applied to synthetics such as polyvinyl chloride (PVC) , nylons, fluorocarbons, polyolefins, polyurethane prepolymers, polystyrene, and certain of the cellulosic and acrylic resins.
  • PVC polyvinyl chloride
  • a thermosetting polymer may be selected, the term “thermosetting” being used in its usual sense to define a polymer that solidifies or sets irreversibly when heated or chemically cured.
  • FIG. 5 is a view of the interior face of a bag, and illustrates another embodiment of the present invention.
  • the interior face 25 of one of the sheets that forms the bag includes an opening precursor structure shown as the perforated line 26.
  • the opening precursor structure could also comprise structures such as slits or score lines.
  • a second polymer sheet 27 is superimposed on the first polymer sheet 25 and covers the perforated line 26 on the exterior of the first sheet 25 and thus on the exterior of a bag structure that includes the first sheet 25.
  • the second sheet 27 has a tear strength that is greater than the tear strength of the perforated line 26, and less than the tear strength of the remainder of the first sheet 25. In that manner, the second sheet 27 provides both an appropriate sealing structure over the perforated line 26, as well as a structure that is easier to open than would be a bag structure formed entirely of the material of the first sheet 25.
  • the invention provides an easily openable package that can be formed of stronger polymers that would otherwise be difficult to open. If necessary, the structure provides for sterilization and physical integrity of the package that is much higher than when other opening systems are incorporated. As noted with respect to the structural aspects of the invention, the ribbed and non-ribbed portions of a sheet (or bag precursor tube) could be extruded from a common opening.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Medical Preparation Storing Or Oral Administration Devices (AREA)
  • Bag Frames (AREA)

Abstract

Structure d'ouverture pour un matériau en feuille polymère tel que ceux utilisés pour former des emballages à fermeture étanche, y compris des emballages stériles à fermeture étanche pour des applications médicales. Ladite structure d'ouverture comporte une feuille polymère formée d'une pluralité de nervures adjacentes qui s'étendent de manière linéaire dans lesquelles le polymère est fortement orienté dans la direction linéaire définie par les nervures. Lesdites nervures comprennent des parties qui ont généralement une résistance plus faible dans la direction d'orientation que les parties restantes des nervures pour former ainsi une partie plus facilement déchirable et donc plus facilement ouvrable de la feuille polymère, sans affaiblir par ailleurs l'intégrité mécanique de la feuille.
PCT/US1995/015778 1994-12-07 1995-12-05 Structure d'ouverture d'emballage polymere WO1996017792A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU45090/96A AU4509096A (en) 1994-12-07 1995-12-05 Polymeric package opening structure

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US35094394A 1994-12-07 1994-12-07
US08/350,943 1994-12-07

Publications (1)

Publication Number Publication Date
WO1996017792A1 true WO1996017792A1 (fr) 1996-06-13

Family

ID=23378871

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1995/015778 WO1996017792A1 (fr) 1994-12-07 1995-12-05 Structure d'ouverture d'emballage polymere

Country Status (2)

Country Link
AU (1) AU4509096A (fr)
WO (1) WO1996017792A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1223115A1 (fr) * 2001-01-15 2002-07-17 Amcor Flexibles France Bandelette de scellage pour un emballage et emballage la comportant

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3323707A (en) * 1966-02-15 1967-06-06 Leonard H King Tear-open package
BE743156A (en) * 1969-12-15 1970-06-15 Thermoplastic film or sheet with ribs for - container production
US3780781A (en) * 1971-09-07 1973-12-25 Seisan Nipponsha Kk Openable bag

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3323707A (en) * 1966-02-15 1967-06-06 Leonard H King Tear-open package
BE743156A (en) * 1969-12-15 1970-06-15 Thermoplastic film or sheet with ribs for - container production
US3780781A (en) * 1971-09-07 1973-12-25 Seisan Nipponsha Kk Openable bag

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1223115A1 (fr) * 2001-01-15 2002-07-17 Amcor Flexibles France Bandelette de scellage pour un emballage et emballage la comportant
FR2819489A1 (fr) * 2001-01-15 2002-07-19 Danisco Flexible France Bandelette de scellage pour un emballage et emballage la comportant

Also Published As

Publication number Publication date
AU4509096A (en) 1996-06-26

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