Patent Description:
Flexible packages that dissolve in water have found use for packaging dry, granulated soaps such as laundry and dishwasher soaps, chemical additives, industrial cleaners, paint mixing, and other uses where pre-measured quantities of a substance are advantageous. For example, water-soluble flexible packages made from polyvinyl alcohol can dissolve in water and many other liquids, causing release of the package contents.

Repulpable packages made from cellulose materials have found increasing use as the demand for repulpable materials increases. As with flexible packages that dissolve in water, flexible packages that are repulpable have generally been limited to use with pre-measured quantities of foods and other contents. Until now, these packages have been pre-filled by the manufacturers and closed using heat sealing, gluing, and similar techniques. The consumer does not have a convenient way to open the packages and vary the contents before using them. Consumers must typically accept the pre-measured quantities of ingredients and do not have the flexibility to vary them. Moreover, consumers do not have a convenient way to prepare their own repulpable packages containing pre-measured quantities of ingredients, because such packages cannot be readily closed and sealed by the consumers.

Until now, flexible packages that are re-closeable have generally been constructed of plastics that are not repulpable. The entire field of flexible packages whose contents are determined by consumers has been dominated by non-repulpable materials. Re-closeable sandwich bags and other re-closeable food packages are typically non-repulpable.

There is a need or desire in the art for repulpable flexible packages that can be opened and closed by consumers.

There is also a need or desire in the art for pre-packaged repulpable flexible packages whose contents can be readily varied at the consumer level.

There is also a need or desire for repulpable flexible packages that can be filled by consumers with desired contents to desired levels, sealed, and stored for future use.

<CIT> relates to a laminated packaging material biodegradable under uncontrolled composting conditions comprises a bioplastic sealant layer compostable under uncontrolled composting conditions, and a cellulose barrier layer compostable under uncontrolled composting conditions, wherein the barrier layer is bonded to the sealant layer with a water-based dry bond adhesive including a hydroxyl or an aziridine cross-linking coreactant and having polyurethanes or acrylics only in concentrations less than <NUM>% of the dry weight of the packaging material.

The present invention is directed to a repulpable re-closeable flexible package and a repulpable zipper for a repulpable flexible package. As used herein, the term "repulpable" refers to a cellulose material whose fibers can be broken down and returned to the pulp state and suspended in a liquid such as water. The dissociated fibers can then be re-used (e.g., re-combined) to make a new cellulose material. Examples of repulpable materials include various papers, cardboards and other cellulose-based materials. The repulpable zipper enables the production of fully repulpable flexible packages that can be opened and re-closed by the consumer.

The invention is directed to a repulpable, re-closeable flexible package according to claim <NUM>.

The invention is further directed to a repulpable zipper according to claim <NUM>.

The invention is further directed to a method of making a repulpable zipper for a re-closable flexible package according to claim <NUM>.

With the foregoing in mind, it is a feature and advantage of the invention to provide a repulpable flexible package that can be opened and closed by consumers.

It is also a feature and advantage of the invention to provide a repulpable flexible package that can be filled by consumers with desired contents to desired levels, sealed, and stored for future use.

It is also a feature and advantage of the invention to provide a repulpable zipper that enables the production of repulpable flexible packages that can be opened and closed by consumers, and the contents varied.

The foregoing characteristics and advantages of the invention will become further apparent from the following Detailed Description, read in conjunction with the drawings.

The present invention is directed to a repulpable, re-closeable flexible package, a repulpable zipper for a re-closeable flexible package, and a method of making a repulpable zipper for a re-closeable flexible package. The repulpable, re-closeable flexible package and the repulpable zipper can have any conventional structure that is known in the art of re-closeable flexible packages. The specific structures described herein are exemplary.

Referring to <FIG>, a repulpable, re-closeable flexible package <NUM> includes a repulpable front wall <NUM> and a repulpable back wall <NUM>, each one having a first side <NUM>, a second side <NUM>, a bottom <NUM> and a top <NUM>. The repulpable front and back walls <NUM> and <NUM> are joined together at their respective first sides <NUM>, second sides <NUM> and bottoms <NUM>. Each of the respective joinders can be a fold (if the front and back walls are continuous), or a heat seal, or any suitable joint that is essentially permanent and cannot be opened and re-closed.

The respective tops <NUM> of the front and back walls <NUM> and <NUM> define a mouth that can be opened and closed using a repulpable zipper <NUM> defined by interlocking elements (exemplified in <FIG>) that are connected to and/or adjacent to the tops <NUM> of the respective front and back walls. As shown in <FIG>, for example, the repulpable zipper <NUM> includes at least one (or more than one) first interlocking element <NUM>, <NUM> connected to the front wall <NUM> and at least one (or more than one) second interlocking element <NUM>, <NUM> connected to the back wall <NUM> of the repulpable, re-closeable flexible package <NUM>. The repulpable zipper <NUM> is movable between a first open position that disengages each of the first interlocking elements <NUM>, <NUM> from each of the second interlocking elements <NUM>, <NUM>, and a second closed position that engages each of the first interlocking elements <NUM>, <NUM> to each of the respective second interlocking elements <NUM>, <NUM>.

Depending on the specific structure of the repulpable zipper, the engagement and disengagement of the first and second interlocking elements can be accomplished using manual pressure, in which the consumer uses his or her hands to press the interlocking elements into engagement or separate them into disengagement, or with the aid of a repulpable slider <NUM> having an opening end 12A and a closing end 12B. The slider <NUM> can be movable between a first position adjacent to the first sides <NUM> that opens the mouth at the tops <NUM> and a second position adjacent to the second sides <NUM> that closes the mouth at the tops <NUM> of the flexible package <NUM>.

The repulpable zipper <NUM> and the repulpable slider <NUM> can have a wide variety of configurations. <FIG> illustrates a double zipper embodiment with first and second zipper profiles <NUM> and <NUM> upwardly terminating in first and second upper flanges <NUM> and <NUM>, and downwardly terminating in first and second lower flanges <NUM> and <NUM>. The first interlocking elements <NUM> and <NUM> are female interlocking elements formed by arcuate extending arms <NUM> terminating in detent hooks <NUM>. The second interlocking elements <NUM> and <NUM> are male interlocking elements having first and second shafts <NUM> and <NUM> terminating in respective first and second arrowhead detent elements <NUM> and <NUM>. The second zipper profile <NUM> also includes a hinge structure <NUM> formed by an inner flange <NUM>, from which the second interlocking elements <NUM> and <NUM> extend, and an outer flange <NUM> joining at pivot point <NUM> downwardly adjacent from the top surface of second zipper profile <NUM>.

The repulpable zipper <NUM> shown in <FIG> is like that of <FIG> except that one of the first interlocking elements <NUM> is replaced with a first arm <NUM> with a self-mating hook that can mate with a similar or identical structure, with guide post <NUM>, and one of the second interlocking elements <NUM> is replaced with a second arm <NUM> with a self-mating hook. <FIG> shows another embodiment of repulpable zipper <NUM> having a first zipper profile <NUM> with first interlocking elements <NUM>' and <NUM>' and a second zipper profile <NUM> with second interlocking elements <NUM> and <NUM>, all of which are male elements. In each of the foregoing embodiments, the first interlocking elements can be connected or adapted for connection to the front wall <NUM>, and the second interlocking elements can be connected or adapted for connection to the back wall <NUM> of the repulpable, re-closeable flexible package <NUM>. In various embodiments (not shown), the zipper can be continuous between the front and back walls so that the at least one interlocking element connected (or adapted for connection) to the front wall is the same as the at least one interlocking element connected (or adapted for connection) to the back wall.

The repulpable zipper <NUM> includes <NUM>% to <NUM>% by weight of a water-soluble polymer and <NUM>% to <NUM>% by weight of a repulpable material. The repulpable material is a plant-based cellulose material as described below. The repulpable material can be either blended with the water-polymer or coated with the water-soluble polymer, or both. For example, paper can be coated so that the inside surfaces of the walls have a coating on them to help facilitate forming/sealing the package as well as providing better surfaces to attach the zipper. A re-pulpable cellulose material can also be coated with minor amounts of a water-insoluble polymer such as an acrylic, provided that the overall zipper <NUM> is repulpable. Exemplary water-soluble polymers and repulpable cellulose materials are described below.

The repulpable zipper <NUM> and the repulpable slider <NUM> (when present) can include any suitable water-soluble polymer that will dissolve in water or aqueous liquids. Suitable water-soluble polymers include without limitation alkali-soluble polyvinyl acetate copolymers, ethylene-maleic anhydride copolymers, polyacrylates, polyethers, polyvinyl alcohol, ethylene vinyl alcohol, polyvinyl pyrrolidone, polyacrylamides, styrene-maleic anhydride, water-soluble cellulosic ethers, hydroxyethylcellulose, methycellulose, sodium carboxymethylcellulose, and combinations thereof. When present, the repulpable slider <NUM> can be formed using the same water-soluble polymer as the remainder of the repulpable zipper <NUM>, or can be formed using a different (e.g., stiffer) water-soluble polymer.

Alkali-soluble polyvinyl acetate copolymers are soluble in aqueous solutions that have been treated with a base. Suitable polymers include polyvinyl acetate copolymers in which the vinyl acetate is copolymerized with an acidic comonomer. The acid-base reactions dissociate the polymer molecules into liquid monomers, resulting in dissolution. Ethylene-maleic anhydride copolymers include both linear copolymers of ethylene and maleic anhydride and copolymers that have been crosslinked with anhydride, free acid or amide-ammonium salt side chains.

Suitable water-soluble polyacrylates include polymers of acrylic acid, polymers of methacrylic acid, and combinations thereof. Also included are polymers of acrylic acid and polymers of methacrylic acid that have been neutralized with bases to their salt forms. Suitable polyethers include polyoxyethylenes, polymethyl ethyl ethers, and combinations thereof. Polyoxyethylenes are typically waxy and should therefore be used in combination with a stiffer polymer such as ethylene vinyl alcohol or polyvinyl alcohol. Polyvinyl ethers readily dissolve in water at temperatures up to about <NUM>° C and become less soluble at higher temperatures.

Polyvinyl alcohol and ethylene vinyl alcohol are both soluble in water and possess the structural integrity and flexibility needed for repulpable zippers, with or without a repulpable slider. These polymers can be readily extruded into the shapes and profiles that are typical of packaging zippers. These polymers can also be readily heat sealed or laminated onto paper, which can be used to form the walls <NUM> and <NUM> of a repulpable flexible package <NUM> as described above.

High molecular weight polyvinyl pyrrolidone is soluble in water and various organic solvents. Because of its tackiness, can suitably be combined with another water-soluble polymer and/or a suitable amount of repulpable (e.g., plant-based cellulose) material that contributes structural integrity to the repulpable zipper. High molecular weight polyacrylamide exhibits similar tackiness and can also be combined with another water-soluble polymer that contributes structural integrity. Styrene-maleic anhydride copolymers are soluble in alkaline water and in some organic solvents. These resins can readily be heat sealed or otherwise laminated to paper and other plant-based cellulose materials, the latter of which can be used to form the walls <NUM> and <NUM> of a repulpable flexible package <NUM> as described above.

Various cellulosic polymers can be used to form the repulpable zipper <NUM> of the invention. Water-soluble cellulose ether polymers prepared from alpha-cellulose are hygroscopic and have film-forming properties useful in preparing the water-soluble zippers and connecting them to the front and back walls <NUM> and <NUM> of the flexible package. Hydroxyethylcellulose, prepared by reacting alkali cellulose with ethylene oxide, can be made completely water-soluble or only alkali-soluble depending on the extent of the reaction. This polymer can be used alone or in combination with another, and is highly compatible with the foregoing polyvinyl acetate, polyvinyl alcohol and ethylene-vinyl alcohol polymers and copolymers. Polymers of methycellulose and polymers of sodium carboxymethylcellulose also exhibit excellent water-solubility and are compatible with paper and other cellulose materials that can be used to form the front and back walls <NUM> and <NUM> of the flexible package <NUM>.

The repulpable zipper <NUM> and the repulpable slider <NUM> (when present) can include any suitable repulpable material within the ranges stated above. The term "repulpable" refers to a paper or other sheet material that can be converted back into dissociated pulp or fibers for possible recycling. For purposes of the repulpable zipper <NUM> and repulpable slider <NUM>, suitable repulpable materials include plant-based cellulose materials. Suitable plant-based cellulose materials include without limitation wood pulp, paper fibers, cotton, linen, silk, wool, and combinations thereof. While other (e.g., non-cellulose) materials may qualify as repulpable, the plant-based cellulose materials, combined with suitable amounts of water-soluble polymer, contribute the mechanical and structural integrity that is needed for functioning as a repulpable zipper <NUM> for a flexible package.

The materials used to form the repulpable, re-closeable flexible package <NUM> (excluding the zipper <NUM>) fall into the same two categories. The first category includes water-soluble flexible polymers that dissolve in water, and possibly other liquids, releasing the contents of the package. These types of packages are used for packaging dry, granulated soaps such as laundry and dishwasher soaps, chemical additives, industrial cleaners, paint mixing, and other uses where pre-measured quantities of a substance are advantageous. The second category includes repulpable materials, such as plant-based cellulose materials that are intended to replace disposable non-repulpable plastic packages. The repulpable flexible package includes <NUM>% to <NUM>% by weight of a water-soluble polymer and <NUM>% to <NUM>% by weight of a repulpable material.

Suitable polymers may include any of the foregoing polymers and polymer combinations that are useful for the repulpable zipper. Suitable water-soluble polymers include without limitation alkali-soluble polyvinyl acetate copolymers, ethylene-maleic anhydride copolymers, polyacrylates, polyethers, polyvinyl alcohol, ethylene vinyl alcohol, polyvinyl pyrrolidone, polyacrylamides, styrene-maleic anhydride, water-soluble cellulosic ethers, hydroxyethylcellulose, methycellulose, sodium carboxymethylcellulose, and combinations thereof. In these embodiments, the water-soluble polymer used to form the body of the flexible package <NUM> (i.e., the front wall <NUM> and the back wall <NUM>) can be the same water-soluble polymer or polymer combination used to form the zipper <NUM> or can be a different water-soluble polymer or polymer combination.

The repulpable material can be plant-based cellulose material. The plant-based cellulose material can include without limitation wood pulp, paper fibers, cotton, linen, silk, wool, and combinations thereof. While other (e.g., non-cellulose) materials may qualify, the plant-based cellulose materials, combined with suitable amounts of water-soluble polymer, contribute the mechanical and structural integrity that is needed for functioning as a front wall <NUM> and back wall <NUM> for a flexible package <NUM>.

The repulpable zipper <NUM> and repulpable flexible package <NUM> can be designed to satisfy various standards for repulpability. Re-pulpability can be measured using the Fibre Box Association's (FBA's) "Voluntary Standard for Repulping and Recycling Corrugated.

Claim 1:
A repulpable, re-closeable flexible package (<NUM>) comprising:
repulpable front and back walls (<NUM>, <NUM>), each including a first side (<NUM>), a second side (<NUM>), a top (<NUM>) and a bottom (<NUM>);
the repulpable front and back walls (<NUM>, <NUM>) being joined together at the respective first sides, second sides and bottoms;
a re-closeable mouth defined by the top of the front wall and the top of the back wall; and
a repulpable zipper (<NUM>) positioned at the top of the front wall (<NUM>) and the top of the back wall (<NUM>), the repulpable zipper (<NUM>) including at least one interlocking element (<NUM>, <NUM>) connected to the front wall (<NUM>) and at least one interlocking element (<NUM>, <NUM>) connected to the back wall (<NUM>);
the repulpable zipper (<NUM>) being movable between a first open position that disengages the at least one interlocking element (<NUM>, <NUM>) connected to the front wall (<NUM>) from the at least one interlocking element (<NUM>, <NUM>) connected to the back wall (<NUM>) and a second closed position that engages the at least one interlocking element (<NUM>, <NUM>) connected to the front wall (<NUM>) to the at least one interlocking element (<NUM>, <NUM>) connected to the back wall (<NUM>);
characterized in that the repulpable zipper (<NUM>) includes <NUM>% to <NUM>% by weight of a water-soluble flexible polymer and <NUM>% to <NUM>% by weight of a plant-based cellulose material.