HOLBERT VICTOR PAUL (US)
KILBOURNE KERRI (US)
PASTOR RICHARD (US)
HAYNES KELLY WINEGARDEN (US)
HOLBERT VICTOR PAUL (US)
KILBOURNE KERRI (US)
PASTOR RICHARD (US)
| WO1994024019A2 | 1994-10-27 |
| EP1749756A2 | 2007-02-07 | |||
| US3311032A | 1967-03-28 | |||
| EP1679270A1 | 2006-07-12 | |||
| EP1468936A2 | 2004-10-20 | |||
| US6026953A | 2000-02-22 |
Claims
What is claimed is:
1. A container comprising: a plurality of inner compartments for containing discrete articles; a flexible outer wrapper surrounding the inner compartments, the outer wrapper having a top, wherein the top has a plurality of access openings, each access opening aligned with an individual inner compartment; and a plurality of label closures, each label closure sealed with an adhesive to the top around an access opening, wherein each label closure may be at least partially removed to provide access to the discrete articles contained within the aligned inner compartment.
2. The container of claim 1 further comprising an inner frame having a plurality of sections, the sections forming the inner compartments.
3. The container of claim 1 or 2 wherein the adhesive comprises a resealable adhesive.
4. The container of claim 3 wherein the adhesive comprises an emulsion acrylic adhesive.
5. The container of claim 3 wherein the adhesive comprises a solvent based adhesive.
6. The container of claim 3 wherein the adhesive comprises hot melt block copolymer adhesive.
7. The container of any one of the preceding claims wherein the discrete articles comprise food articles.
8. The container of claim 7 wherein each inner compartment contains a single serving of the food articles.
9. The container of any one of claims 1 to 7 wherein the discrete articles within each section are different.
10. The container of any one of the preceding claims further comprising a tamper-evident structure.
11. The container of any one of the preceding claims wherein the top of the outer wrapper comprises a plurality of flaps, each flap having substantially the same dimension as an access opening and affixed to a label closure.
12. The container of any one of the preceding claims wherein each label closure comprises a lift tab.
13. The container of claim 12 wherein the lift tab is adhesive free.
14. The container of claim 12 wherein the lift tab comprises a deadened adhesive.
15. The container of claim 12 wherein the lift tab comprises a finger hole.
16. The container of any one of claims 1 to 15 wherein each label closure is transparent.
17. The container of any one of claims 1 to 15 wherein the top of the outer wrapper includes graphics around the openings and each label includes graphics that match the graphics on the top.
18. The container of any one of claims 1 to 17 wherein each label closure has substantially the same dimensions.
19. The container of any one of claims 1 to 17 wherein at least one label closure has dimensions that are different than those of other label closures.
20. The container of any one of the preceding claims wherein the label closures are resealable.
21. A container comprising: a plurality of inner compartments for containing discrete articles, the inner compartments comprising a first compartment and at least one successive compartment aligned in succession; a flexible outer wrapper surrounding the inner compartments, the outer wrapper having a top, wherein the top has a plurality of access openings and regions between the access openings, each access opening aligned with an individual inner compartment; and a label closure sealed to the top of the outer wrapper around the access openings with a first adhesive having a first peel strength, wherein the label closure may be at least partially removed to provide access to the discrete articles contained within the first inner compartment and to successive compartments, wherein the label closure is sealed to the top of the outer wrapper in the regions between the access openings with a second adhesive having a second peel strength, the second peel strength being greater than the first peel strength.
22. The container of claim 21 wherein the first adhesive comprises a resealable adhesive.
23. The container of claim 22 wherein the adhesive comprises an emulsion acrylic adhesive.
24. The container of claim 22 wherein the adhesive comprises a solvent based adhesive.
25. The container of claim 22 wherein the adhesive comprises hot melt block copolymer adhesive.
26. The container of any one of claims 21 to 25 wherein the discrete articles comprise food articles.
27. The container of any one of claims 21 to 26 wherein each inner compartment contains a single serving of the food articles.
28. The container of any one of claims 21 to 27 further comprising a tamper-evident structure.
29. The container of any one of claims 21 to 28 wherein the top of the wrapper comprises a plurality of flaps, each flap having substantially the same dimension as an access opening and affixed to the label closure.
30. The container of any one of claims 21 to 29 wherein the label closure comprises a lift tab.
31. The container of claim 30 wherein the lift tab is adhesive free.
32. The container of claim 30 wherein the lift tab comprises a deadened adhesive.
33. The container of claim 30 wherein the lift tab comprises a finger hole.
34. The container of any one of claims 21 to 33 wherein the label closure is transparent.
35. The container of any one of claims 21 to 33 wherein the top of the outer wrapper includes graphics around the openings and the label includes graphic that match the graphics on the top.
36. The container of any one of claims 21 to 35 wherein the second adhesive comprises a heat seal adhesive.
37. The container of any one of claims 21 to 36 wherein the label closure is resealable. |
Title: MULTIPLE ACCESS CONTAINER
Cross Reference to Related Application
This application claims priority from provisional application U.S. Serial No. 60/884,256 filed January 10, 2007. The provisional application is hereby incorporated by reference in its entirety.
Technical Field
This invention relates to a container, and in particular, to a container having multiple compartments that can be individually opened. In one embodiment, the multiple compartments can be individually opened and reclosed repeatedly.
Background
Flexible packages for containing multiple items generally include a single opening for gaining access to the package contents. The opening may include a peelable closure that, in some instances, can be repeatedly opened and closed. However, these containers often do not provide a convenient means for gaining access to a limited amount or particular item of the product within the packaging, while the remaining items stay secure within the package.
Summary
The present invention provides a container having multiple compartments or sections that can be individually opened. Access to the items within a particular compartment is provided while the items within the other compartments remain secure within the container. If the contents of the container comprise food articles, the contents within the unopened compartments retain their freshness. The individual compartments may contain, for example, a single serving of a food item, or an amount of food having a specified caloric content. Alternatively, each compartment may contain a different variety of a product. For example, if the container is used
to package cookies, a first compartment may contain chocolate chip cookies, a second compartment may contain peanut butter cookies, and a third compartment may contain oatmeal cookies, etc. The container is not limited to food items. Examples of other uses include, but are not limited to, containers for arts and craft supplies, fishing tackle, hardware items, office supplies, etc.
In one embodiment of the invention, there is provided a container comprising an inner frame having a plurality of sections for containing discrete articles; a flexible outer wrapper surrounding the inner frame, the outer wrapper having a top, wherein the top has a plurality of access openings, each access opening aligned with an individual inner frame section; and a plurality of label closures, each label closure sealed with an adhesive to the top of the outer wrapper around an access opening, wherein each label closure may be at least partially removed to provide access to the discrete articles contained within the aligned inner frame section.
In another embodiment of the invention, there is provided a container comprising a plurality of inner compartments for containing discrete articles; a flexible outer wrapper surrounding the inner compartments, the outer wrapper having a top, wherein the top has a plurality of access openings, each access opening aligned with an individual inner compartment; and a plurality of label closures, each label closure sealed with an adhesive to the top of the outer wrapper around an access opening, wherein each label closure may be at least partially removed to provide access to the discrete articles contained within the aligned inner compartment. In yet another embodiment of the invention, there is provided a container comprising: a plurality of inner compartments for containing discrete articles, the inner compartments comprising a first compartment and at least one successive compartment aligned in succession; a flexible outer wrapper surrounding the inner compartments, the outer wrapper having a top, wherein the top has a plurality of access openings and regions between the access openings, each access opening aligned with an individual inner compartment; and a label closure sealed to the top of the outer wrapper around the access openings with a first adhesive having a first peel strength, wherein the label closure may be at least partially removed to provide access to the discrete
articles contained within the first inner compartment and to successive compartments, wherein the label closure is sealed to the top of the outer wrapper in the regions between the access openings with a second adhesive having a second peel strength, the second peel strength being greater than the first peel strength.
Drawings
Figure 1 is a perspective view of a container in a closed configuration in accordance with one embodiment of the present invention. Figure 2 is a perspective view of if the container of Figure 1 in a partially opened configuration.
Figure 3 is a perspective view of an inner frame suitable for use with the container of Figures 1 and 2.
Figures 4 and 5 are top views of an embodiment of the invention in which the graphics of the wrapper are visible through the label closures in the closed and partially opened positions, respectively.
Figure 6 is a perspective view of another container of the invention having multiple openings.
Figure 7 is a perspective view of a container of the invention having multiple openings of different sizes.
Figure 8 is a perspective view of a container of the invention having multiple openings of different shapes.
Figure 9 is a perspective view of a container of the invention having a single label closure to provide access to multiple openings to the container. Figure 10 is a label closure having lift tab comprising a finger hole.
Detailed Description
Containers
In a first embodiment of the invention, there is provided a container comprising an inner frame having a plurality of sections for containing discrete articles; a flexible outer wrapper surrounding the inner frame, the outer wrapper having a top, wherein the top has a plurality of access openings, each access opening aligned with an individual inner frame section; and a plurality of label closures, each label closure sealed with an adhesive to the
top of the outer wrapper around an access opening, wherein each label closure may be at least partially removed to provide access to the discrete articles contained within the aligned inner frame section.
Referring now to the drawings, and initially to Figures 1 and 2, a container according to one embodiment of the invention is shown. Container 10 includes a flexible wrapper 11 having a top 12, a bottom 13, opposing sides 14a and 14b and opposing ends 15a and 15b. Flaps 16a, 16b, 16c and 16d, when pulled back from container 10, form openings 18a, 18b, 18c and 18d, respectively. Label closures 20a, 20b, 20c, and 2Od are affixed to flaps 16a, 16b, 16c and 16d, respectively, with an adhesive. Each label closure may include a lift tab 17.
Container 10 may be partially opened by lifting tab 17b and pulling back to expose opening 18b and the contents therein. Label closure 20b includes adhesive 19 to seal label closure 20b to the top 12 and permits opening of container 10. The lift tab portion of the label closure may be adhesive free. Alternatively, the lift tab may include a deadened adhesive.
In addition to the flexible wrapper 11 , container 10 may include an inner frame for holding the contents of the container. Referring to Figure 3, inner frame 22 may be formed of a rigid material such as plastic or cardboard, and includes barrier walls 23 that form distinct sections 24 to separate the container contents. Sections 24 are aligned with the openings 18, so that upon pulling back label closure 20b, for example, access to the contents of section 24b is provided through opening 18b.
Graphics may be formed on the label closures 20a-20d that align with the corresponding graphics on top 12 when the label closures are in the closed or flat position in top 12. In one embodiment, the label closures 20a- 2Od are transparent so that graphics on top 12 are visible through the label closures. Figures 4 and 5 illustrate a food container in which the graphics are formed on the top and are visible through the label closures when the closures are in the closed position. An individual label closure may be peeled back to provide access to the contents within the aligned inner frame section.
In additional embodiments, the container may include multiple openings of various configurations. For example, as illustrated in Figure 6, container 60 has dual longitudinal closure labels 20a and 20b affixed to
openings 18a and 18b, respectively. Figure 7 illustrates container 70, which has multiple openings 18a, 18b and 18c of different sizes, and label closures 20a, 20b and 20c, respectively, affixed thereto. Figure 8 illustrates container 80, which has multiple openings 18a, 18b and 18c of different shapes and sizes, and label closures 20a, 20b and 20c respectively, affixed thereto. Thus the container may include label closures having substantially the same dimensions as illustrated in Figures 1 , 4 and 6, or include label closures wherein at least one label closure has dimensions that are different that the dimensions of the other label closures, as illustrated in Figures 7 and 8. In one embodiment of the invention, the container comprises a plurality of inner compartments for containing discrete articles; a flexible outer wrapper surrounding the inner compartments, the outer wrapper having a top, wherein the top has a plurality of access openings, each access opening aligned with an individual inner compartment; and a plurality of label closures, each label closure sealed with an adhesive to the top of the outer wrapper around an access opening, wherein each label closure may be at least partially removed to provide access to the discrete articles contained within the aligned inner compartment. The inner compartments may be formed, for example, by heat sealing an internal layer of the flexible outer wrapper to itself or by heat sealing an inner flexible liner to itself. This container, in one embodiment, does not include an inner frame. The compartments formed within the container are aligned with the openings in the flexible outer wrapper, over which the label closures are affixed.
In one embodiment illustrated in Figures 9, container 90 includes outer wrapper 11 having multiple openings 18a, 18b and 18c within the top 12. The inner frame sections within the container are aligned with the openings 18a- 18c. A single label closure 20 is affixed to top 12 of the container, and may be peeled back in stages to provide access to a single opening at a time, while remaining secured to the top 12 over the remaining sections. The adhesive of label closure 20 in the regions 91a and 91 b between the openings may be different than the adhesive used to secure the label closure to the outer portions of the openings so as to provide more peel resistance, allowing one section at a time to be exposed. Alternatively, flexible wrapper 11 may be heat sealed to the inner frame within the flexible wrapper in the regions 91a
and 91 b. Thus, for example, the contents of the remaining sections retain their freshness until the label closure is further peeled back to provide access to the successive sections. In one embodiment of the container illustrated in Figure 9, the container does not include an inner frame. The inner compartments are formed by heat sealing an internal layer of the flexible outer wrapper to itself or by heat sealing an inner flexible liner to itself.
Referring to Figure 10, in one embodiment, the label closure 20 has a lift tab 17 having a finger hole 22 formed therein. The finger hole 22 may be formed, for example, by die cutting the facestock film of the label closure. The flexible wrapper of the container may be made of single or multiple layers of, e.g., paper, polymer or composites of paper and polymer, or of other materials such as cardboard, metal foils or metallized polymers. In one embodiment, the flexible wrapper is a bag formed of multiple layers of paper. The paper may be light, medium or heavy weight, with heavy weight paper typically used. There can be from two to about eight layers with three layers being typical. In another embodiment, the flexible wrapper is a bag formed of multiple layers of heavy weight paper, in which the inner layer includes an inner, product-facing poly-lined surface. The innermost layer of the bag, which is exposed to the product contained in the bag, may be paper lined with a polymer on the side facing the product. This feature avoids penetration into the paper of components of the product, such as oils or fats from foods. The inner, polymer-lined layer may also be used to add strength to the container as a whole. In another embodiment, the flexible wrapper is a bag formed of multiple layers of paper, in which the outer layer includes an outer-facing polymer-lined surface. The outer-facing polymer-lined surface may be used to protect the bag as a whole from environmental effects, including moisture, dirt, oils, physical damage, etc.
When the container is a flexible bag, one or more of the layers may be formed of paper. Although paper of any weight can be employed as a substrate material, paper having weights in the range of from about 30 to about 150 pounds per ream are useful, or from about 40 to about 120 pounds per ream are useful. In one embodiment, the paper is 100 pound paper, or 80 pound paper, or 60 pound paper, or 50 pound paper. In one embodiment, the paper has a weight greater than 45 pounds, or greater than 55 pounds. As
used herein, weights of paper are given in pounds per ream, and a ream is defined as 3000 square feet (ft 2 ). Thus, for example, for 30 pound paper, one ream of the paper weighs 30 pounds (13.64 kg). Examples of specific papers that can be used include 41 -pound offset grade bleached kraft paper; 78- pound bleached kraft paper, etc., in the range from 30 pound to 150 pound paper.
In one embodiment, the outer surface of the flexible wrapper is a semi- gloss elite paper stock, having a weight of at least about 45 pounds. In another embodiment, the outer surface of the flexible wrapper is semi-gloss elite paper stock having a weight of at least about 60 pounds. In another embodiment, the paper is semi-gloss coated one-side bleached kraft face paper stock, having a weight of at least about 30 pounds. In another embodiment, the outer surface of the flexible wrapper is polycoated paper stock having a weight of at least about 50 pounds. Flexible wrappers made of paper or paper-based substrates are useful because of the wide variety of applications in which they can be employed. Paper is also relatively inexpensive and has desirable properties including antiblocking, antistatic, and dimensional stability. Paper can potentially be recycled. Any type of paper, having sufficient tensile strength to be handled in conventional paper coating and treating apparatus and to reliably hold for storage, handling and transportation the desired contents, can be employed as the substrate. Thus, any type of paper can be used depending upon the end use and particular users' preferences. Included among the types of paper which can be used are clay coated paper, glassine, polymer coated paper, paperboard from straw, bark, wood, cotton, flax, cornstalks, sugarcane, bagasse, bamboo, hemp, and similar cellulose materials prepared by such processes as the soda, sulfite or sulfate (kraft) processes, the neutral sulfide cooking process, alkali-chlorine processes, nitric acid processes, semi- chemical processes, etc. Alternatively, the substrate for the flexible wrapper may be a polymer film. The polymer film may be non-oriented film, uniaxially oriented film or biaxially oriented film. When uniaxially oriented, the orientation may be either in the machine direction or in the cross direction. Useful polymer films include polystyrenes, polyolefins, polyamides, polyesters, polycarbonates, polyvinyl
alcohol, poly(ethylene vinyl alcohol), polyvinyl chloride, polyurethanes, polyacrylates including copolymers of olefins such as ethylene and propylene with acrylic acids and esters, copolymers of olefins and vinyl acetate, ionomers and mixtures thereof. In one embodiment, the polymer film material is a polyolefin.
The polyolefin films may comprise homopolymers and copolymers of monoolefins having from 2 to about 12 carbon atoms, or from 2 to about 8 carbon atoms, or from 2 to about 4 carbon atoms per molecule. Examples of such homopolymers include polyethylene, polypropylene, poly-1-butene, etc. The examples of copolymers within the above definition include copolymers of ethylene with from about 1 % to about 10% by weight of propylene, copolymers of propylene with about 1% to about 10% by weight of ethylene or 1-butene, etc. Films prepared from blends of copolymers or blends of copolymers with homopolymers also are useful. The polymer films may be extruded in mono- or multilayers.
The flexible wrapper of the container may be formed of a layer of polymer sheeting. Suitable polymers include any of the polymers identified above, or known for use in such applications. While a single layer is generally adequate, in appropriate circumstances multiple layers of polymer sheeting may be used. In another embodiment, the bag may be formed of a layer of plastic sheeting and one or more additional layers of, e.g., paper.
Another type of material that can be used as the flexible wrapper is a polycoated kraft liner that includes a kraft liner that is coated on either or both sides with a polymer coating. The polymer coating may include any of the above-described polymers, for example, high, medium, or low density polyethylene, propylene, polyester, and other similar polymer films. The polymer is coated onto the substrate surface to add strength and/or dimensional stability to the substrate. The weights of these substrates typically range from about 30 to about 100 pounds per ream, or from about 40 to about 94 pounds per ream. In total, the final substrate typically includes between about 10% and about 40% polymer and from about 60% to about 90% paper. For two sided coatings, the quantity of polymer is approximately evenly divided between the top and bottom surface of the paper.
The flexible wrapper may include heavy-duty bags made from multi-ply high strength polyolefins, such as LDPE polyethylene, as well as other woven or nonwoven, synthetic or natural web materials. Such bags are typically used to package materials such as dry cement, salt, potting soil, small landscaping rocks, pet food and similar heavy materials.
The face layer or layers of the bag liner or bag outer surface may comprise a major amount of a thermoplastic copolymer or terpolymer derived from ethylene or propylene (preferably ethylene) and a functional monomer selected from the group consisting of alkyl acrylate, acrylic acid, alkyl acrylic acid, vinyl acetate and combinations of two or more thereof. In one embodiment, the above-described polymers may be used as the face layer. In one embodiment, the functional monomer is selected from the group consisting of alkyl acrylate, acrylic acid, alkyl acrylic acid, and combinations of two or more thereof. The alkyl groups in the alkyl acrylates and the alkyl acrylic acids typically contain 1 to about 8 carbon atoms, and in one embodiment 1 to about 2 carbon atoms. The copolymer or terpolymer generally has a melting point in the range of about 50 0 C to about 120 0 C, and in one embodiment about 60°C to about 11 °C.
The functional monomer(s) component of the copolymer or terpolymer ranges from about 1 to about 15 mole percent, and in one embodiment about 1 to about 10 mole percent of the copolymer or terpolymer molecule. Examples include: ethylene/vinyl acetate copolymers; ethylene/methyl acrylate copolymers; ethylene/ethylacrylate copolymers; ethylene/butyl acrylate copolymers; ethylene/methacrylic acid copolymers; ethylene/acrylic acid copolymers; ethylene/methacrylic acid copolymers containing sodium or zinc (also referred to as ionomers); acid-, anhydride- or acrylate-modified ethylene/vinyl acetate copolymers; acid- or anhydride-modified ethylene/acrylate copolymers; anhydride-modified low density polyethylenes; anhydride-modified linear low density polyethylene, and mixtures of two or more thereof. In one embodiment, ethylene/vinyl acetate copolymers that are particularly useful include those with a vinyl acetate content of at least about 20% by weight, and in one embodiment about 20% to about 40% by weight, and in one embodiment about 22% to about 28% by weight, and in one embodiment about 25% by weight.
Examples of commercially available copolymers and terpolymers that can be used as the face layers include the ethylene/vinyl acetate copolymers available from DuPont under the trade name ELVAX ® . These include ELV AX ® 3120, which has a vinyl acetate content of 7.5% by weight and a melting point of 99 0 C, ELVAX ® 3124, which has a vinyl acetate content of 9% by weight and a melting point of 77°C, ELVAX ® 3150, which has a vinyl acetate content of 15% by weight and a melting point of 92°C, ELVAX ® 3174, which has a vinyl acetate content of 18% by weight and a melting point of 86 0 C, ELVAX ® 3177, which has a vinyl acetate content of 20% by weight and a melting point of 85°C, ELVAX ® 3190, which has a vinyl acetate content of 25% by weight and melting point of 77°C, ELVAX ® 3175, which has a vinyl acetate content of 28% by weight and a melting point of 73 0 C, ELVAX ® 3180, which has a vinyl acetate content of 28% by weight and a melting point of 70°C, ELVAX ® 3182, which has a vinyl acetate content of 28% by weight and a melting point of 73°C, and ELVAX ® 3185, which has a vinyl acetate content of 33% by weight and a melting point of 61 0 C, and ELVAX ® 3190LG, which has a vinyl acetate content of 25% by weight, a melting point of about 77 0 C and a glass transition temperature (T 9 ) of about -38.6°C. Ethylene acid copolymers available from DuPont under the trade name NUCREL ® can also be used. These include NUCREL ® 0407, which has a methacrylic acid content of 4% by weight and a melting point of 109 0 C, and NUCREL ® 0910, which has a methacrylic acid content of 8.7% by weight and a melting point of 100°C. The ethylene/acrylic acid copolymers available from Dow Chemical under the trade name PRIMACOR ® are also useful. These include PRIMACOR ® 1430, which has an acrylic acid monomer content of 9.5% by weight, a melting point of about 97°C and a T 9 of about -7.7°C. The ethylene/methyl acrylate copolymers available from Chevron under the trade name EMAC ® can be used. These include EMAC ® 2205, which has a methyl acrylate content of 20% by weight and a melting point of 83 0 C, and EMAC ® 2268, which has a methyl acrylate content of 24% by weight, a melting point of about 74°C and a T 9 of about - 40.6 0 C. lonomers (polyolefins containing ionic bonding of molecular chains) also are useful as the face layers, lonomer resins available from DuPont under the trade name SURLYN ® can also be used. These are identified as
being derived from sodium, lithium or zinc and copolymers of ethylene and methacrylic acid. These include SURLYN ® 1601 , which is a sodium containing ionomer having a melting point of 98 0 C, SURLYN ® 1605, which is a sodium containing ionomer having a melting point of about 9O 0 C and a T 9 of about - 20.6 0 C, SURLYN ® 1650, which is a zinc containing ionomer having a melting point of 97 0 C, SURLYN ® 1652 which is a zinc containing ionomer having a melting point of 100 0 C, SURLYN ® 1702, which is a zinc containing ionomer having a melting point of 93°C, SURLYN ® 1765-1 , which is a zinc containing ionomer having a melting point of 95 0 C, SURLYN ® 1707, which is a sodium containing ionomer having a melting point of 92°C, SURLYN ® 1802, which is a sodium containing ionomer having a melting point of 99 0 C, SURLYN ® 1855, which is a zinc containing ionomer having a melting point of 88°C, SURLYN ® 1857, which is a zinc containing ionomer having a melting point of 87°C, and SURLYN ® 1901 , which is a sodium containing ionomer having a melting point of 95°C.
Polycarbonates also are useful as the face layer, and these are available from the Dow Chemical Co. (CALIBRE ® ) G. E. Plastics (LEXAN ® ) and Bayer (MAKROLON ® ). Most commercial polycarbonates are obtained by the reaction of bisphenol A and carbonyl chloride in an interfacial process. Molecular weights of the typical commercial polycarbonates vary from about 22,000 to about 35,000, and the melt flow rates generally are in the range of from 4 to 22 g/10 min. Closure Label
The closure label generally comprises a facestock film and an adhesive layer. Other layers may be included in the label construction. The polymer facestock layer may be a monolayer film or a multilayer film. The multilayer film may comprise from two to ten or more layers. The polymer facestock may be oriented or not oriented. Depending on the end use of the label, the polymer facestock may be transparent or opaque. Opaque facestocks generally comprise a polymer as described below and one or more pigments to provide the facestock, or one layer of a multilayer facestock with the desired color. Pigments useful for this purpose are well known in the art. For example, white films can be prepared by introducing titanium dioxide and
other white pigments into the polymer. Carbon black may be introduced to provide a black or grey facestock or film.
A wide variety of polymer film materials are useful in preparing the facestocks useful for label closure. For example, the polymer film material may include polymers and copolymers such as at least one polyolefin, polyacrylate, polystyrene, polyamide, polyvinyl alcohol, poly(alkylene acrylate), poly(ethylene vinyl alcohol), poly(alkylene vinyl acetate), polyurethane, polyacrylonitrile, polyester, polyester copolymer, fluoropolymer, polysulfone, polycarbonate, styrene-maleic anhydride copolymer, styrene- acrylonitrile copolymer, ionomers based on sodium or zinc salts of ethylene methacrylic acid, cellulosics, polyacrylonitrile, alkylene-vinyl acetate copolymer, or mixtures of two or more thereof.
The polyolefins which can be utilized as the facestock film material include polymers and copolymers of olefin monomers containing 2 to about 12 carbon atoms such as ethylene, propylene, 1-butene, etc., or blends of mixtures of such polymers and copolymers. In one embodiment the polyolefins comprise polymers and copolymers of ethylene and propylene. In another embodiment, the polyolefins comprise propylene homopolymers, and copolymers such as propylene-ethylene and propylene-1-butene copolymers. Blends of polypropylene and polyethylene with each other, or blends of either or both of them with polypropylene-polyethylene copolymer also are useful. In another embodiment, the polyolefin film materials are those with a very high propylenic content, either polypropylene homopolymer or propylene-ethylene copolymers or blends of polypropylene and polyethylene with low ethylene content, or propylene-1-butene copolymers or blend of polypropylene and poly-1-butene with low butene content. Useful propylene homopolymers and copolymers are described in U.S. Pat. No. 5,709,937 (Adams et al). The copolymers include propylene-ethylene copolymers containing up to about 10% by weight of ethylene, and propylene-1-butene copolymers containing up to about 15% by weight of 1-butene. Oriented films described in the '937 patent are clear films useful as the facestock in the labels of the present invention. The disclosure of U.S. Pat. No. 5,709,937 is hereby incorporated by reference.
Various polyethylenes can be utilized as the polymer facestock film material including low, medium, and high density polyethylenes, and mixtures thereof. An example of a useful low density polyethylene (LDPE) is Rexene 1017 available from Huntsman. An example of a useful high density polyethylene (HDPE) is Formoline LH5206 available from Formosa Plastics. In one embodiment the polymer film material comprises a blend of 80 to 90% HDPE and 10-20% of LDPE.
The propylene homopolymers which can be utilized as the polymer facestock film material, either alone, or in combination with a propylene copolymer as described herein, include a variety of propylene homopolymers such as those having melt flow rates (MFR) from about 0.5 to about 20 as determined by ASTM Test D 1238. In one embodiment, propylene homopolymers having MFR's of less than 10, and more often from about 4 to about 10 are particularly useful. Useful propylene homopolymers also may be characterized as having densities in the range of from about 0.88 to about 0.92 g/cm 3 . A number of useful propylene homopolymers are available commercially from a variety of sources, and some useful polymers include: 5A97, available from Dow Chemical and having a melt flow of 12.0 g/10 min and a density of 0.90 g/cm 3 ; DX5E66, also available from Dow Chemical and having an MFI of 8.8 g/10 min and a density of 0.90 g/cm 3 ; and WRD5-1057 from Dow Chemical having an MFI of 3.9 g/10 min and a density of 0.90 g/cm 3 . Useful commercial propylene homopolymers are also available from Fina and Montel.
Examples of useful polyamide resins include resins available from EMS American Grilon Inc., Sumter, S. C. under the general trade name Grivory such as CF6S, CR-9, XE3303 and G-21. Grivory G-21 is an amorphous nylon copolymer having a glass transition temperature of 125°C, a melt flow index (DIN 53735) of 90 ml/10 min and an elongation at break (ASTM D638) of 15. Grivory CF65 is a nylon 6/12 film grade resin having a melting point of 135°C, a melt flow index of 50 ml/10 min, and an elongation at break in excess of 350%. Grilon CR9 is another nylon 6/12 film grade resin having a melting point of 200 0 C, a melt flow index of 200 ml/10 min, and an elongation at break at 250%. Grilon XE 3303 is a nylon 6.6/6.10 film grade resin having a melting point of 200 0 C, a melt flow index of 60 ml/10 min, and an elongation
at break of 100%. Other useful polyamide resins include those commercially available from, for example, International Paper of Wayne, N.J. under the Uni- Rez product line, and dimer-based polyamide resins available from Bostik, International Paper, Fuller, Henkel (under the Versamid product line). Other suitable polyamides include those produced by condensing dimerized vegetable acids with hexamethylene diamine. Examples of polyamides available from International Paper include Uni-Rez 2665; Uni-Rez 2620; Uni- Rez 2623; and Uni-Rez 2695.
Polystyrenes can also be utilized as the polymer facestock material and these include homopolymers as well as copolymers of styrene and substituted styrene such as alpha-methyl styrene. Examples of styrene copolymers and terpolymers include: acrylonitrile-butene-styrene (ABS); styrene-acrylonitrile copolymers (SAN); styrene butadiene (SB); styrene- maleic anhydride (SMA); and styrene-methyl methacrylate (SMMA); etc. An example of a useful styrene copolymer is KR-10 from Phillips Petroleum Co. KR-10 is believed to be a copolymer of styrene with 1 ,3-butadiene.
Polyurethanes also can be utilized as the polymer film material, and the polyurethanes may include aliphatic as well as aromatic polyurethanes. The polyurethanes are typically the reaction products of (A) a polyisocyanate having at least two isocyanate (— NCO) functionalities per molecule with (B) at least one isocyanate reactive group such as a polyol having at least two hydroxy groups or an amine. Suitable polyisocyanates include diisocyanate monomers, and oligomers.
Useful polyurethanes include aromatic polyether polyurethanes, aliphatic polyether polyurethanes, aromatic polyester polyurethanes, aliphatic polyester polyurethanes, aromatic polycaprolactam polyurethanes, and aliphatic polycaprolactam polyurethanes. Particularly useful polyurethanes include aromatic polyether polyurethanes, aliphatic polyether polyurethanes, aromatic polyester polyurethanes, and aliphatic polyester polyurethanes. Examples of commercial polyurethanes include Sancure 2710 ® and/or
Avalure UR 445 ® (which are equivalent copolymers of polypropylene glycol, isophorone diisocyanate, and 2,2-dimethylolpropionic acid, having the International Nomenclature Cosmetic Ingredient name "PPG-17/PPG- 34/IPDI/DMPA Copolymer"), Sancure 878 ® , Sancure 815 ® , Sancure 1301 ® ,
Sancure 2715 ® , Sancure 1828 ® , Sancure 2026 ® , and Sancure 12471 ® (all of which are commercially available from Noveon, Cleveland, Ohio), Bayhydrol DLN (commercially available from Bayer Corp., McMurray, Pa.), Bayhydrol LS-2033 (Bayer Corp.), Bayhydrol 123 (Bayer Corp.), Bayhydrol PU402A (Bayer Corp.), Bayhydrol 1 10 (Bayer Corp.), Witcobond W-320 (commercially available from Witco Performance Chemicals), Witcobond W-242 (Witco Performance Chemicals), Witcobond W-160 (Witco Performance Chemicals), Witcobond W-612 (Witco Performance Chemicals), Witcobond W-506 (Witco Performance Chemicals), NeoRez R-600 (a polytetramethylene ether urethane extended with isophorone diamine commercially available from Avecia, formerly Avecia Resins), NeoRez R-940 (Avecia), and NeoRez R-960 (Avecia).
Examples of such aliphatic polyether polyurethanes include Sancure 2710 ® and/or Avalure UR 445 ® , Sancure 878 ® , NeoRez R-600, NeoRez R- 966, NeoRez R-967, and Witcobond W-320.
In one embodiment, the facestocks comprises at least one polyester polyurethane. Examples of these urethanes include those sold under the names "Sancure 2060" (polyester-polyurethane), "Sancure 2255" (polyester- polyurethane), "Sancure 815" (polyester-polyurethane), "Sancure 878" (polyether-polyurethane) and "Sancure 861 " (polyether-polyurethane) by the company Sanncor, under the names "Neorez R-974" (polyester- polyurethane), "Neorez R-981 " (polyester-polyurethane) and "Neorez R-970" (polyether-polyurethane) by the company Avecia, and the acrylic copolymer dispersion sold under the name "Neocryl XK-90" by the company Avecia. Polyesters prepared from various glycols or polyols and one or more aliphatic or aromatic carboxylic acids also are useful film materials. Polyethylene terephthalate (PET) and PETG (PET modified with cyclohexanedimethanol) are useful film forming materials that are available from a variety of commercial sources including Eastman. For example, Kodar 6763 is a PETG available from Eastman Chemical. Another useful polyester from DuPont is Selar PT-8307, which is polyethylene terephthalate.
Acrylate polymers and copolymers and alkylene vinyl acetate resins (e.g., EVA polymers) also are useful as the film forming materials in the preparation of the constructions of the invention. Commercial examples of
available polymers include Escorene UL-7520 (Exxon), a copolymer of ethylene with 19.3% vinyl acetate; Nucrell 699 (duPont), an ethylene copolymer containing 11 % of methacrylic acid, etc. lonomers (polyolefins containing ionic bonding of molecular chains) also are useful. Such ionomers are described above with reference to the flexible wrapper. Polycarbonates also are useful, and these are also described above.
In one embodiment, the facestock polymer material may comprise fluorinated polymer. The fluorinated polymer includes a thermoplastic fluorocarbon such as polyvinylidene fluoride (PVDF). The fluorinated polymer also can include copolymers and terpolymers of vinylidene fluoride. A useful thermoplastic fluorocarbon is the polyvinylidene fluoride known as Kynar, a trademark of Pennwalt Corp. This polymer is a high molecular weight (400,000) polymer, which provides a useful blend of durability and chemical resistance properties. Generally, a high molecular weight PVDF resin, with a weight average molecular weight of about 200,000 to about 600,000 is used.
The polymer facestock material may be free of inorganic fillers and/or pigments for clear facestocks and clear labels, or the polymer facestock material may be cavitated and/or contain inorganic fillers and other organic or inorganic additives to provide desired properties such as appearance properties (opaque or colored films), durability and processing characteristics. Nucleating agents can be added to increase crystallinity and thereby increase stiffness. Examples of useful materials include calcium carbonate, titanium dioxide, metal particles, fibers, flame retardants, antioxidant compounds, heat stabilizers, light stabilizers, ultraviolet light stabilizers, antiblocking agents, processing aids, acid acceptors, etc. Opaque and/or white facestocks are often utilized when the labels described herein do not contain a metal layer overlying the facestock layer.
The polymer facestock material is chosen to provide a continuous polymer film in the film structures of this invention with the desired properties such as improved tensile strength, elongation, impact strength, tear resistance, and optics (haze and gloss). The choice of polymeric facestock forming material also is determined by its physical properties such as melt viscosity, high speed tensile strength, percent elongation etc. In one
embodiment, clear or transparent facestocks are used in the label construction when clear or transparent labels are desired.
The thickness of the polymer facestock may be from about 0.1 to about 10 mils, or from about 1 to about 5 mils. In one embodiment the thickness of the facestock is from about 1 to about 3 mils. The facestock may comprise a single layer, or the film can be a multilayer film of two or more adjacent layers. For example the film can comprise one layer of a polyolefin and one layer of a blend of a polyolefin and a copolymer of ethylene and vinyl acetate (EVA). In another embodiment the film comprises three layers, a base or core layer of, for example, a polyolefin, and skin layers in both sides of the base or core layer that may be comprised of the same or different polymer blends. The individual layers of a multilayer facestock may be selected to provide desirable properties.
The monolayer and multilayer film facestocks useful in the label closure can be manufactured by those processes known to those skilled in the art such as by casting or extrusion. In one embodiment, the films are manufactured by polymer extrusion or coextrusion processes. The extrudate or coextrudate of polymeric film materials is formed by simultaneous extrusion from a suitable known type of extrusion or co-extrusion die, and in the case of a coextrudate, the layers are adhered to each other in a permanently combined state to provide a unitary coextrudate.
In addition to coextrusion, the multilayer film facestocks useful in the present invention may be prepared by extrusion of a continuous film to form one layer followed by the application of one or more additional layers on the extruded layer by extrusion of one or more additional layers; by lamination of a preformed polymer film to a preformed functional film; or by deposition of additional layers on the preformed film from an emulsion or solution of a polymeric film forming material.
In one embodiment, the facestocks are not oriented. That is, the facestock and films are not subjected to a hot-stretching and annealing step. In other embodiments, the facestock contained in the labels used in the present invention may be oriented in the machine direction (uniaxially) or in both the machine and cross directions (biaxially) by hot-stretching and annealing by techniques well known to those skilled in the art. For example,
the films may be hot-stretched in the machine direction only at a ratio of at least 2:1 and more often, at a ratio of between about 2:1 to about 9:1. After the film has been hot stretched, it is generally passed over annealing rolls where the film is annealed or heat-set at temperatures in the range of from about 5O 0 C, more often 100 0 C. to about 150 0 C, followed by cooling. In another embodiment, the facestock is a biaxially oriented.
It is desirable that the films exhibit a degree of stiffness in the machine direction and the cross direction to facilitate handling, printing and dispensing. Thus, in one embodiment, the stiffness in the machine direction, and the cross direction should be at least about 14 Gurley (mg), as determined using TAPPI Test T543 pm and in a further embodiment the Gurley stiffnesses in both directions are within about 5 Gurley units (sometimes referred to as a balanced stiffness).
The surface energy of both surfaces of the facestock can be enhanced by treatments such as corona discharge, flame, plasma, etc. to provide the surfaces with desirable properties such as improved adhesion to subsequently applied layers. Procedures for corona treating and flame treating of polymer films are well known to those skilled in the art. In one embodiment, a facestock is corona discharge treated on the upper surface and flame treated on the lower surface. Adhesive
The adhesive layer utilized in the label closure may be directly coated on the lower surface of the facestock layer, or the adhesive may be transferred from a liner with which the facestock is combined. Typically, the adhesive layer has a thickness of from about 0.4 to about 1.6 mils (10 to about 40 microns). Adhesives suitable for use in labelstocks of the present invention are commonly available in the art. Generally, these adhesives include pressure-sensitive adhesives, heat-activated adhesives, hot melt adhesives, etc. Pressure-sensitive adhesives (PSAs) are particularly preferred. These include acrylic based adhesives as well as other elastomers such as natural rubber or synthetic rubber containing polymers or copolymers of styrene, butadiene, acrylonitrile, isoprene and isobutylene. The acrylic adhesive may comprise an emulsion based adhesive or a solvent based adhesive. PSAs are also well known in the art and any of the known
adhesives can be used with the facestocks of the present invention. If the container is used to contain food articles, an appropriate adhesive comprises one approved for use with food, including those approved by the FDA for such use. In one embodiment, the adhesive layer comprises a resealable adhesive. The resealable pressure sensitive adhesive enables the label closure to be peeled back to provide access to the opening, and then to be reapplied over the opening. Thus a particular compartment or section of the container may be repeatedly opened and reclosed. In one embodiment, the pressure sensitive adhesive composition comprises a copolymer prepared by emulsion polymerization of a monomer mixture comprising (a) at least one alkyl acrylate monomer, the alkyl group of which has from about 4 to about 12 carbon atoms, present in an amount of from about 90% to about 96% by weight, based on the total weight of the monomer mixture; (b) at least one unsaturated carboxylic acid monomer containing from about 3 to about 5 carbon atoms, present in an amount of about 1 % to about 5% by weight of the monomer mixture; (c) at least one hard monomer, present in an amount of about 1 % to about 5% by weight of the monomer mixture; and (d) at least one external crosslinker. In one embodiment, the adhesive comprises a hot-extrudable pressure sensitive hot melt adhesive that is resealable. Such adhesives may comprise block copolymers. Hot melt block copolymer adhesives are disclosed in published application US 2004/0077759, the disclosure of which is hereby incorporated by reference. In addition to the facestock layer and the adhesive layer, the label closure may further comprise a tamper evident structure. The tamper evident structure provides an indication to the consumer whether the container has been previously opened or otherwise tampered with. Tamper evident structures are known to those skilled in the art. Examples of tamper evident label structures include those disclosed in US Patents 5,411 ,295; 5,876,816 and 6,294,236, the disclosures of which are hereby incorporated by reference. The tamper evident structure may be a structure distinct from the label closure. For example, the tamper evident structure may include a tamper evident tape applied to at least a portion of the perimeter of the label
structure. Alternatively, the tamper evident structure may include a removable film applied over the label closure.
While the invention has been explained in relation to its preferred embodiments, it is to be understood that various modifications thereof will become apparent to those skilled in the art upon reading the specification. Therefore, it is to be under stood that the invention disclosed herein is intended to cover such modifications as fall within the scope of the appended claims.