Compositions – Humidostatic – water removive – bindive – or emissive
Reexamination Certificate
1998-07-27
2001-04-10
Silbaugh, Jan H. (Department: 1732)
Compositions
Humidostatic, water removive, bindive, or emissive
C502S402000, C034S095000
Reexamination Certificate
active
06214255
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to the use of desiccant material in packaging; more particularly, the present invention relates to packaging material having a desiccant contained therein. Still more particularly, the present invention relates to polymers having desiccating agents applied to or blended or mixed therein. The invention further relates to desiccant entrained polymers that include means by which desiccant located within interior portions of the polymer structure are exposed to moisture that is exterior to the polymer body. The desiccant entrained polymer of the present invention is particularly useful in the manufacture of containers and packaging for items requiring moisture reduced environments.
BACKGROUND OF THE INVENTION
There are many articles that are preferably stored, shipped and/or utilized in an environment that is as moisture free as possible. Therefore, containers having the ability to absorb excess moisture trapped therein have been recognized as desirable. One application in which moisture absorbing containers are desired is for the shipment and storage of medications whose efficacy is compromised by moisture. The initial placement of medicines into a sealed moisture free container is usually controllable. Furthermore, the container for the medicine is selected so that it has a low permeability to moisture. Therefore, the medication will normally be protected from moisture until it reaches the end user. Once the medicine is received by the consumer, however, the container must be repeatedly opened and closed to access the medication. Each time the container is opened and unsealed, moisture bearing air will most likely be introduced into the container and sealed therein upon closure. Unless this moisture is otherwise removed from the atmosphere or head space of the container, it may be detrimentally absorbed by the medication. For this reason, it is a well known practice to include a desiccating unit together with the medication in the container.
Other items, such as electronic components, may require reduced moisture conditions for optimal performance. These components may be sealed in containers, but excess moisture that is initially trapped therein must be removed. Furthermore, the housings may not be completely moisture tight, and moisture may be allowed to seep into the container. This moisture must also be retained away from the working components. For these reasons, it is important to include a desiccating agent within the housing for absorbing and retaining excess moisture. Because of the delicacy of many of the components that are to be protected from the moisture, it is important that the desiccant used not be of a “dusting” nature that may contaminate and compromise the performance of the components. Therefore, it has been recognized as advantageous to expose a desiccating agent to the interior space of such containers, while at the same time shielding the working components from actual contact with the desiccating material, including desiccant dust that may be produced therefrom.
In other instances, moisture may be released from items that have been placed in containers or sealed in packaging wrap for shipping and/or storage. Prime examples of such items are food stuffs that release moisture during shipping and storage. In the instance of containers that are sealed and substantially impermeable to moisture, the released moisture will remain within the container about the product. If not removed, this released moisture may have ill effects on the very item that released the moisture. It has been found that a substantial amount of moisture is released from certain food products within the first forty-eight (48) hours after manufacture and packaging. This released moisture will remain about the product until removed. If the moisture is not removed shortly after its release, it may cause the food to degrade into a condition that is not saleable. In these cases, desiccants may be included together with the contained items to continually absorb the released moisture until the product is unpacked. In this way, a relatively dry environment is maintained about the stored item.
The need to eliminate moisture from within sealed containers has been previously recognized. Early attempts to achieve these goals included the provision of desiccant materials in fabric or similar bags that are placed in the containers, together and commingled with the matter being shipped or stored. A consumer related problem, however, exists when the desiccant is loose and commingled together with consumable items. If not carefully and thoroughly processed upon unpacking, the desiccant may not be separated from the consumables and could harm a person if unknowingly ingested.
Several inventions have been patented that include both structures and processes that provide means for absorbing moisture by way of a desiccant that is included in various forms of packaging. A most basic example is found in the disclosure of U.S. Pat. No. 3,326,810 issued Jun. 20, 1967 to Dolan et al for a DESICCANT PACKAGE. That patent includes disclosure of a non-dusting silica gel desiccant bag. The bag is created from two sheet of nylon mesh that are bonded into a bag within which the silica gel is contained. The nylon mesh has micro-porous polyurethane bonded to it and through which moisture passes while at the same time containing the desiccating silica gel within the bags interior. It is explained that the micro porous structure of the polyurethane allows the moisture to be transmitted thereacross, but is nonpermeable to desiccant dust that may be produced by the silica gel.
Another known method by which a desiccant is included in a container is to provide a special side-compartment having limited exposure to the interior of the container. Within the side-compartment, desiccating materials or drying agents are held for the purpose of absorbing moisture that is present within the primary portion of the container. Examples of such inventions are found in U.S. Pat. No. 4,834,234 issued May 30, 1989 to Sacherer et al for a CONTAINER FOR TEST STRIPS. Sacherer provides a drying agent cell or compartment within the cap portion of a container for test strips that are used in the analysis of body fluids. Those strips must be maintained in a moisture reduced environment for which Sacherer's invention is intended. It is disclosed that the drying agent cell is covered by a water vapor-permeable cardboard disc that separates that cell from the interior of the container. It is the cardboard disc that provides a barrier between the desiccant or drying agent and the container's interior space. A similar example is found in U.S. Pat. No. 5,114,003 issued May 19, 1992 to Jackisch et al for a TABLET VIAL WITH DESICCANT IN BOTTOM. Jackisch includes disclosure of a desiccant canister that is secured to the bottom inside of a container's base. The desiccant canister within which the desiccating material is contained is initially sealed to prevent the absorption of moisture. Immediately prior to use, the desiccant canister is punctured and communication of moisture across the container is allowed to the desiccant.
Oftentimes, separate capsules of desiccant that are expensive to produce are provided within the packaging. U.S. Pat. No. 4,783,206 issued Nov. 8, 1988 to Cullen et al for an ADSORBENT CARTRIDGE describes an elongated hollow cylindrical body fabricated of polyethylene, polyester or polypropylene. It is intended that the sides of the body member of the cartridge be moisture impermeable and that membrane disc coverings be provided as end caps to the cartridge's body through which moisture, odors and other gases are permeable. A desiccating agent is enclosed within the cartridge thereby maintaining the desiccant separate from other items commonly contained within the common container. By the cartridge's construction, it is intended that moisture pass only through the end caps constructed of spun-bonded polyolefin, and not the rigid, high density plastic side wa
Capitol Specialty Plastics, Inc.
Dreier & Baritz LLP
McDowell Suzanne E
Silbaugh Jan H.
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