Special receptacle or package – With specified material for container or content – For container
Reexamination Certificate
1997-04-07
2002-11-26
Gehman, Bryon P. (Department: 3629)
Special receptacle or package
With specified material for container or content
For container
C383S001000, C383S113000
Reexamination Certificate
active
06484879
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a multi-layer water soluble or dispersible packaging film and its use in packages for containing potentially hazardous organic chemicals. More particularly, the present invention relates to a water soluble or dispersible packaging system having a continuous film barrier on the interior portion of the package for containing agricultural chemicals having a tendency to adversely affect or otherwise be deleterious to the outer film portion of the water soluble or dispersible packaging system.
BACKGROUND OF THE INVENTION
Pesticides, such as herbicides, insecticides, fungicides and other types of agricultural chemicals (referred to herein as “agrichemicals”) are often potentially harmful materials and are commonly made in concentrated form which can be as a solid, a liquid, a dispersion or a gel, for example. Such materials typically need to be diluted with water prior to use. Numerous other types of hazardous and toxic materials are also commonly sold and used on a commercial basis. Containers are needed for the aforementioned types of hazardous and toxic materials in order to conveniently distribute, sell and utilize such materials.
Typically, such containers are metal or blow molded plastic. However, there are hazards and difficulties in handling, storing and using such types of containers and materials. In addition, particularly with highly concentrated materials, hazards exist when such concentrates are diluted for use, such as when pouring the concentrate into a tank or other container. For example, the concentrated material can splash or spill in unintended locations, causing unintended human, animal or other contact with the concentrate.
In addition, disposal of the metal or plastic containers can be a problem since some residual concentrated material will remain in the original container. Thus, disposal of such containers can become an environmental problem.
It is known to package certain materials, including certain liquids in water soluble bags consisting of a layer of cold water soluble polyvinyl alcohol. Such packaging is disclosed in U.S. Pat. No. 5,351,831, for example. However, such packaging and similar types of packaging are not suitable for containing agrichemicals that deleteriously affect cold water soluble polyvinyl alcohol film, such as by chemical or physical reaction with it, including dissolving the cold water soluble film. Consequently, a need exists for a suitable cold water soluble or dispersible container that can contain agrichemicals and other materials that chemically, physically or otherwise deleteriously react with the water soluble film that forms the water soluble bag. In addition, a need exists for a cold water soluble or dispersible bag for storing such agrichemicals and other materials that is reliable and easy to produce.
SUMMARY OF THE INVENTION
In accordance with the present invention, a multi-layer cold water soluble or dispersible packaging film is provided which comprises: (i) a first “outer” continuous cold water soluble or dispersible film layer of sufficient thickness and strength for use as a package to contain chemicals, and (ii) a second “inner” continuous water soluble or dispersible film layer which is both chemically differentiated from and thinner than said first layer. The multi-layer film of the present invention is suitable for use as a package to contain potentially hazardous materials, particularly chemicals that dissolve water soluble film or chemically, physically or otherwise deleteriously react with or adversely affect water soluble film. The water soluble or dispersible packaging system prepared from the multi-layer film generally is conveniently in the form of a bag, a pouch or a sachet. Other conventional container configurations also are contemplated by the packaging system of the invention.
As used herein, the term “chemical” includes all types of potentially hazardous chemical materials, particularly organic chemicals including, but not limited to, agrichemicals. The term “agrichemicals” includes, for example, agronomically useful chemicals from the following classes: plant nutrients, plant growth regulators, plant protection agents such as pesticides (e.g., herbicides, insecticides, nematocides, acaricides, molluscicides, fungicides, etc.), activity promoters, penetrating agents, synergists, antidotes and safeners, activators, compatibility agents, and adjuvants. The term “agrichemicals” also includes agrichemical compositions (mixtures of one or more agrichemicals with any conventional agronomically acceptable carrier or diluent). The multi-layer film of the present invention can be used to make water soluble or dispersible packages that are suitable for containing chemicals such as agrichemicals or agrichemical compositions in the form of liquids, solids, or gels. Suitable liquids are, for example, in the form of dispersions, solutions, suspensions, emulsions and colloids. Solids are in the form of powders, granules and prills, for example. The term “cold water” means liquid water at a temperature of less than 50° C., preferably lower than 35° C., for example, between 5° C. and 35° C. “Cold water soluble” means completely soluble in cold water. “Dispersible” means disintegration or dissipation as fine particles. Preferably, the dispersed particles are small enough to pass through the orifice of a conventional agrichemical spray apparatus or are filterable without plugging the spray orifice or filter of a conventional agrichemical sprayer. For example, particles having a mean particle size of from about 0.1 to about 250 microns as measured by the CIPAC MT176 test for dissolution capacity of water soluble sachets are considered to be dispersible for the purpose of the present invention. The term “substantially adversely affect” in the context of contact with cold water soluble film by an agrichemical material or other chemical material means that the material is not suitable for containment in a package made of the film because of any deleterious effect caused by contact of the material and the film, whether a chemical or physical reaction including, for example, dissolving the film by the material and unwanted physical leaching of film components into the material. In addition, the material stored in the package can affect the film material by, for example, physically altering the properties of the film such as extraction of plasticizer which makes the film brittle, making the film insoluble or otherwise unsuitable for use in packaging agrichemicals.
The multi-layer cold water soluble or dispersible film in accordance with one aspect of the invention includes a first outer continuous layer of cold water soluble film of sufficient thickness and strength to provide sufficient structural strength for use as a bag to contain liquid. Advantageously, the first or outer film layer may itself contain multiple layers of the same film type (such as co-extruded or tri-extruded cold water soluble films) as is known in the art. The multi-layer cold water soluble or dispersible film of the invention includes a second inner layer, chemically differentiated from the outer layer, which is an inner continuous or substantially continuous barrier layer of a material that can be cold water or hot water soluble or insoluble film securely adhered to and in intimate contact with the outer layer. The inner barrier film layer serves the purpose of preventing, impeding or otherwise reducing the interaction between the contents of a package made from the multi-layer film and the first outer film layer. In one embodiment, the inner barrier film layer is substantially continuous with the outer film layer such that the multi-layer film has edge or border areas which do not contain a barrier film layer to facilitate heat sealing or other sealing means.
When water insoluble or hot but not cold water soluble material is the barrier, the inner continuous layer of water insoluble film is frangible or otherwise lacks sufficient structural integrity to contain the chemical in a bag. Typically
Desmarais Armand J.
Dull Lawrence C.
Knoop Henry E.
Raymond Jean A.
Gehman Bryon P.
Hamilton Thomas
Syngenta Crop Protection Inc.
Teoli, Jr. William A.
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