Flexible bags – Bag having means to facilitate opening it by severing bag... – Line of weakness delineates substantially the entire tearing...
Reexamination Certificate
1999-10-21
2001-04-17
Pascua, Jes F. (Department: 3727)
Flexible bags
Bag having means to facilitate opening it by severing bag...
Line of weakness delineates substantially the entire tearing...
C383S063000, C383S066000
Reexamination Certificate
active
06217216
ABSTRACT:
BACKGROUND OF THE INVENTION
Reclosable plastic bags are used for many purposes, including as biohazard specimen bags for secondary specimen containment in hospitals and laboratories. Even though a biohazard specimen bag must be discarded after being filled with biohazardous material, reclosable bags are commonly preferred to other available bags because of numerous characteristics, including that they are spill resistant, easy to fill and close, easy to reopen for access without compromise of integrity when closed, and may be adapted to be fitted with a tamper evident closure means.
In the laboratory or hospital setting, a specimen of blood, urine, or other biological fluid or tissue is typically first placed in a primary container, such as a tube, vial, or other suitable container, and then placed in the biohazard specimen bag for secondary containment, handling, and, if desired, identification. When filled with a specimen, the reclosable biohazard specimen bag may typically be sent to a destination, such as a pathology laboratory for testing or examination of the specimen.
A conventional, typical biohazard specimen bag may be a reclosable plastic bag with a zip action locking reclosable closure profile that reduces the likelihood of inadvertent compromise or opening, such as from pressure created by changes in the contents. Because of the locking nature of the two interlocking parts or elements of the closure profile, the bag typically will open only if the laboratory worker firmly grasps with both hands the lips of the reclosable bag, created above the closure means, and pulls them apart in opposite directions using both hands.
Generally, however, the laboratory worker, often a pathologist or laboratory technician, wears latex or other suitable protective gloves when handling the bag and/or its contents as protection from possible infectious agents or pathogens, such as bacteria or virus. There is presently a heightened sensitivity to the protection of laboratory workers, especially in light of the recent identification of numerous viral pathogens for which there is no cure, e.g. HIV, HSV, and Ebola. That concern has spurred many rules and regulations regarding the procedures that testing laboratories must follow in handling biospecimens, including wearing protective gloves. The laboratory worker's use of protective gloves may present difficulty in opening the closure means. Often, forceful and excessive pulling of the two lips of the closure means causes sudden opening of the bag and/or tearing along the side seal area. In addition, the contents of the bag may fall out, often breaking or damaging the sealed integrity of the primary container, resulting in contamination of the specimen or the laboratory, and attendant risk to laboratory workers.
Because of the difficulty in opening the reclosable closure means, and the fact that the bag will likely not be reused in any event, many laboratory workers do not bother opening the closure means. Instead, they may cut the bag to reach its contents. While cutting the bag certainly facilitates reaching the bag's contents, the use of a blade presents another opportunity for health hazards and contamination.
The laboratory worker may cut, puncture or injure a hand or finger in the process of cutting the bag. Perforated bags may also be opened without opening the reclosable closure means, but the perforations allow air to enter the bag and also allow the contents to spill or leak from the bag. Because of their decreased structural integrity, perforated bags are not suited for containing biohazardous materials. Perforated bags also may permit tampering with the bag's contents more readily than non-perforated bags, as the perforations may present potential paths of access to the bag's interior without substantial visual damage or alteration to the bag.
SUMMARY OF THE INVENTION
The present invention provides reclosable plastic bags which retain structural integrity when closed, but which can be opened conveniently and relatively safely, even by a laboratory worker who is wearing gloves. Unlike conventional reclosable bags that can be difficult to open while wearing gloves, the present bags contain at least one thin section that can act as a “tear zone” for easy opening, without having to open the closure means. Although the reclosable bags of the present invention can be torn, they do not require perforations to be torn. The reclosable bags of the present invention thus satisfy the structural and functional requirements of hospitals and laboratories, without presenting any risk to the user. Moreover, the reclosable bags of the present invention reduce the likelihood that the contents will spill due to a user being encumbered with gloves trying to access the contents of the bag, because the user will not have to pull as hard as with a conventional bag.
The reclosable plastic bags of the present invention can be made from an extruded plastic bag film web. The bag film web can be cut or otherwise formed into a bag comprising a first wall on which a first closure profile element is disposed and a second wall on which a second closure profile element is disposed. On either wall or both walls, below the closure profile element, the plastic film web can be formed into subsections having different thicknesses. At least one of the subsections is thinner in cross-section, formed of a thinner bag film web, thus creating a “tear zone” that optionally can be made with a substantially linear, not substantially cross-linked, molecular alignment. A sufficient distance from the centerline of the thin subsection, on either side or both sides of the thin subsection, one or more reinforcing strips can be formed of sufficient mass, weight, or strength to reduce at least partially the lateral forces that might otherwise act in or on the thin section during extrusion to cause unacceptable wrinkling of the thin section and/or surrounding sections.
Because of the “tear zone” of the reclosable bags of the present invention, laboratory personnel can be more efficient in opening biohazard bags, which can increase the overall efficiency of the laboratory and provide overall operating costs savings. In addition, the reclosable bags of the present invention are inexpensive to manufacture, and can be produced in a variety of methods, further increasing the bag' desirability. The tear zone preferably does not include any perforations, thereby eliminating or reducing the above-mentioned disadvantages presented by perforated bags.
The reclosable bags of the present invention can also be adapted to include one or more ribs that can contact the outer surfaces of closure profile elements to create at least a partial seal. Such ribs would thus further seal the bag and prevent the contents of the bag from leaking or spilling from the bag, and further prevent the contents from coming into contact with ambient air.
Because there may be unacceptable lateral stresses created in the thin section of polymeric material during extrusion, the present invention optionally also provides reinforcing strips that can be simultaneously extruded or otherwise formed onto a wall of the bag, a sufficient distance from the centerline of the thin section, to reduce the lateral stresses that can otherwise cause undesirable wrinkling of the thin section. A strip is preferably of sufficient mass, weight, or strength to reduce the lateral forces acting in the thin section sufficiently, or can be coupled with other strips. A strip can be extruded by a separate extruder or can be formed integrally with the material of the bag by the use of cavities in the die plates.
Such a strip can be formed in the interior or exterior surfaces of the bag film, can be used to balance the weight of the profile element nearest the thin section, can be formed in balanced pairs, can be integral with the bag film or fused after the bag film is made, and can be formed from the same material as the bag film or from different material. The strips are thus extremely flexible and inexpensive to create.
Gardner & Groff, P.C.
Pascua Jes F.
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