WO1998012488A1

WO1998012488A1 - A reclosable thermoplastic bag having permanent and peelable seals

Info

Publication number: WO1998012488A1
Application number: PCT/US1997/014323
Authority: WO
Inventors: Jose Porchia; Brian C. Dais; Michael J. Banco; Michael A. Babinec; Michael J. Colucci; Douglas P. Gundlach
Original assignee: S.C. Johnson Home Storage, Inc.
Priority date: 1996-09-23
Filing date: 1997-08-14
Publication date: 1998-03-26

Abstract

A reclosable thermoplastic bag (10) suitable for ice cubes and the like. The bag (10) includes two opposing thermoplastic sheets, permanent seals (14) joining the opposing sheets along the side edges (12) and the bottom edge (13), peelable seals (15) joining the opposing sheets at intermittent points between the side edges (12), and a stiffened region positioned along the top edge (11) of each opposing sheet above the peelable seals (15). The stiffened region (16) can include a reclosable fastener means, such as a plastic zipper.

Description

A RECLOSABLE THERMOPLASTIC BAG HAVING PERMANENT AND PEELABLE SEALS

Historically, ice cubes have often been made in rigid, open ice cube trays. The trays had to be carefully oriented in the freezer in order to avoid spilling. Plastic ice cube bags solved the problem to a certain degree. Generally, plastic ice cube bags are made of two sheets of plastic with multiple joints or seals disposed throughout the bag. For example, U.S. Patent 4,181 ,285, issued to Vangedal-Nielsen, describes a freezing mould bag for freezing liquids. The bag has two plastic sheets which are heat sealed at a plurality of positions, forming compartments into which the liquid flows before being frozen. However, in order for the consumer to get the frozen material out of the bag, the bag must be cut or torn apart, thereby destroying the bag.

Other plastic ice cube bags have been developed which need not be completely destroyed in order to get the ice cubes out of the bag. For example, U.S. Patent 4,783,042, issued to Folkmar, discloses a flexible mould bag for freezing ice wherein a relatively weak bonding means is used to form the internal seals, while a stronger bonding means is used to seal the sides of the bag. However, this bag does not provide a convenient surface for a consumer to grasp and gain leverage while opening the bag and peeling apart the internal seals. Furthermore, in order to close the bag for reuse, a separate closure mechanism must be used. It would be an advance in the art of ice bags if a bag could be developed that could be used to store the ice cubes after the ice cubes are broken apart, such as a bag with a closure mechanism that was integral with the bag itself and designed to be reclosable. It would be a further advance in the art if the ice cube bag had a stiffened area along the top of the bag that could be used for leverage when opening the bag and peeling apart the internal seals.

The present invention solves the above identified problems to a large degree, providing a reclosable ice cube bag with a stiffened region above the top of the bag for leverage, and an integral reclosable closure mechanism.

In one aspect, the present invention is a thermoplastic bag, comprising four elements. The first element consists of two opposing thermoplastic sheets, each sheet having a top edge, two side edges and a bottom edge. The second element consists of permanent seals joining the opposing sheets along the side edges and the bottom edge. The third element consists of peelable seals joining the opposing sheets at intermittent points between the side edges. The fourth element is a stiffened region positioned along the top edge of each opposing sheet above the peelable seals, the stiffened region being stiff relative to the opposing sheets.

In a second aspect, the present invention is a reclosable thermoplastic bag comprising four elements. The first element consists of two opposing thermoplastic sheets, each sheet having a top edge, two side edges and a bottom edge. The second element consists of permanent seals joining the opposing sheets along the side edges and the bottom edge. The third element consists of peelable seals joining the opposing sheets at intermittent points between the side edges. The fourth element is a fastener assembly positioned above the peelable seals, the fastener assembly being integral with the bag, the fastener assembly adapted to open or close and providing a stiffened region.

FIG. 1 is a front view of an empty bag of the present invention.

FIG. 2 is a sectional perspective view of a filled bag of the present invention.

Referring now to FIG. 1 , therein is shown a front view of an empty bag 10 of the present invention. Bag 10 is made of two opposing plastic sheets, each sheet having a top edge 11 , two opposing side edges 12, and a bottom edge 13. The bag has permanent seals 14 joining the opposing sheets along the side edges 12 and the bottom edge 13. The bag has peelable seals 15 joining the opposing sheets at intermittent points between the side edges 12, forming a plurality of compartments 17 and passageways 19. The bag also has a stiffened region 16 positioned along the top edge 11 of each opposing sheet above the peelable seals 15, and extending from side edge to side edge. The stiffened region 16 is stiff relative to the stiffness of the opposing sheets. Preferably, the bag 10 also includes a plastic web 18 extending above the stiffened region.

The bag 10 of the present invention is particularly suitable for freezing liquids into small bodies such as freezing water to make ice cubes. Referring now to FIG. 2, therein is shown a section of a filled bag. Water or any other desired liquid 21 flows into the bag from the top. The liquid flows downward through compartments 17 and passageways 19 until the liquid 21 fills all of the compartments 17. As the liquid flows into the compartments, any air that was previously in the compartments escapes through the passageways 19. When the compartments 17 are filled, the opposing sheets bulge out, as shown in FIG. 2. The bag can then be placed in a freezer to allow the liquid to freeze, thereby forming frozen bodies having shapes corresponding to the shapes of the compartments 17. After the liquid has frozen, a user can grasp the bag by the plastic web 18 in order to pull the sides of the bag apart, thereby breaking the peelable seals 15 but not the permanent seals 14. The result is an ordinary reclosable thermoplastic bag having a single, large compartment. The bag can then be manipulated so that the liquid frozen in the passageways 19 breaks. The result is a bag with no compartments containing frozen bodies having shapes that correspond to the shapes of the compartments 17. The frozen bodies slide to the bottom of the bag. The user can remove as many frozen bodies as is desired, and then can reclose the bag and store the bag containing the remaining frozen bodies in the freezer for future use.

The plastic sheets may be made from any suitable thermoplastic film such as, for example, low density polyethylene, linear low density polyethylene, substantially linear copolymers of ethylene and a C3-C8 α-olefin, polypropylene, polyvinylidene chloride, mixtures of two or more of these polymers, or mixtures of one of these polymers with another thermoplastic polymer.

Referring again to FIG. 1 , the side edges 12 and the bottom edge 13 are permanently sealed together with permanent seals 14. The permanent seals 14 can be formed by any desired method, such as, for example, by heat sealing, by applying an adhesive, or by folding the film. Preferably, the permanent seals are formed by heat sealing methods, such as hot wires, hot bars, impulse sealers or ultrasonic sealers. The permanent seals should be such that they do not break apart when a user pulls the opposing sheets apart.

As shown in FIG. 1 , peelable seals 15 are disposed intermittently between the side edges 12 to join the opposing sheets at intermittent points, thereby forming a plurality of compartments 17 and passageways 19 inside the bag 10. The term "peelable seals" is defined herein and in the claims to mean a seal that can easily be torn apart by a user. Thus, the two layers of the opposing sheets are still present at the points of the peelable seals.

The peelable seals 15 can be formed by any desired method, such as pressure sensitive adhesives, heat sensitive adhesives, heat sealing, or a combination of an adhesive together with heat sealing. Preferably, the peelable seals 15 are formed by either a pressure sensitive or heat sensitive adhesive. The adhesive can be applied in a pattern to the opposing sheets and then laminated using pressure and/or heat to form the compartments 17. Alternatively, an adhesive, such as, for example, AFFINITY Resin (The Dow Chemical Company, Midland, Michigan) can be applied or coextruded over the whole sheet followed by pattern sealing with pressure and/or heat. When heat sealing is used for the peelable seals, the heat sealing should be applied at a lower temperature or for a shorter time than the heat sealing for the permanent seals.

The peelable seals and the permanent seals are different kinds of seals. When a user opens the bag after the ice cubes have been formed, the peelable seals are designed to break apart while the permanent seals remain intact. Thus, the peelable seals can be torn apart, while the sides and bottom of the bag remain intact, thereby providing a bag that can be reclosed and used to store the ice cubes or frozen bodies formed in the bag.

The peelable seals 15 are disposed intermittently throughout the bag, such that compartments 17 and passageways 19 are formed between the peelable seals. Compartments 17 form a pattern which can be any desired shape. For example, the pattern can be one of connected circles, as shown in FIGS. 1 and 2, or the pattern can be one of connected rectangles. It is important that the peelable seals be positioned such that the liquid to be frozen can flow through passageways 19 between the individual compartments. Passageways 19 should be of sufficient width to allow liquid to flow between the compartments 17. However, the passageways 19 should be narrow enough that, after being frozen, the frozen bodies can be broken apart.

A stiffened region 16 is disposed along the top edge 11 of the opposing sheets of bag 10. The term "stiffened" is defined herein and in the claims to mean a region that requires less force for a user to bend than the opposing sheets. The stiffness is a function of modulus and thickness. Thus, the stiffness can be changed by altering the material, which changes the modulus, or the stiffness can be changed by altering the thickness of the material used. The stiffened region will thus feel sturdier and less flexible to the user of the bag. The stiffened region provides the user with a surface to grasp as the user fills the bag and/or tears the peelable seals apart after the liquid is frozen.

The stiffened region is positioned above the highest point where the peelable seals are present in the bag. In a preferred embodiment, the stiffened region is a reclosable fastener means. Preferably, the reclosable fastener means is a plastic zipper. As shown in FIG. 2, the plastic zipper comprises a first profile 22 and a second profile 23. The first profile 22 and the second profile 23 are designed to interlock with each other when pressed together, thereby providing a barrier to liquid passing through the plastic zipper. The first and second profiles are also designed to disengage when pulled apart. Thus, the plastic zipper is reclosable since it can be opened and closed multiple times. In this respect, the bag can be conveniently stored in the freezer after the ice cubes are made.

The first profile 22 and the second profile 23 can have any desired shape. For example, the profiles 22 and 23 can have rib and groove shapes, as described in U.S. Patent 5,070,727, alternating hook shapes, as described in U.S. Patent 3,173,184, or a rolling action shape, as described in U.S. Patent 5,007,143.

The stiffened region can be extruded integrally with the opposing sheets of the bag or can be formed separately and attached to the top of the bag after the bag is formed.

Preferably, a plastic web 18 provides an additional surface for the user to grasp as the user fills the bag or tears the peelable seals apart. The plastic web 18 also provides a convenient funnel for filling the bag without spilling liquid all over. The plastic web 18 may extend above the stiffened region 16 or may be a continuation of the stiffened region 16, such that the plastic web 18 itself is stiff relative to the stiffness of the opposing sheets. Preferably, the combination of the plastic web and the stiffened region is at least about 0.5 inches high (1.27 centimeters), more preferably, at least about 1.0 inches high (2.54 centimeters), and most preferably, at least about 1.5 inch high (3.81 centimeters). Preferably, the plastic web is less than 4.0 inches high (10.16 centimeters), more preferably, less than 3.0 inches high (7.62 centimeters), and most preferably, less than about 2.5 inches high (6.35 centimeters). The plastic web can be extruded integrally with the stiffened region or can be formed separately and attached to the top of the stiffened region after the bag is formed.

Preferably, the plastic web is textured. The texture can be, for example, a plurality of small ridges that project from the internal and/or external surface of the plastic web. Alternatively, the texture can be any sort of roughened surface disposed along the plastic web. The texture helps the user to grasp the plastic web with wet hands. The texture also prevents the plastic webs from clinging together through static forces, making it difficult for the user to separate the plastic webs to open the bag.

Claims

CLAIMS :

1. A thermoplastic bag, comprising: a) two opposing thermoplastic sheets, each sheet having a top edge, two side edges and a bottom edge; b) permanent seals joining the opposing sheets along the side edges and the bottom edge; c) peelable seals joining the opposing sheets at intermittent points between the side edges; and d) a stiffened region positioned along the top edge of each opposing sheet above the peelable seals, the stiffened region being stiff relative to the opposing sheets.

2. The bag of Claim 1 , wherein the stiffened region comprises means for opening and reclosing the bag.

3. The bag of Claim 2, wherein the means for opening and reclosing the bag is a plastic zipper disposed along the top edges of the opposing sheets, the zipper being adapted to open or close, the zipper comprising: i) a first profile disposed along one of the opposing sheets; ii) a second profile disposed along the other opposing sheet, the first and second profile designed to interlock with each other when the plastic zipper is closed.

4. The bag of Claim 3, wherein the stiffened region further comprises plastic webs above each closure element of the plastic zipper.

5. The bag of Claim 4, wherein the plastic webs are textured.

6. The bag of Claim 5, wherein the peelable seals form a pattern of connected circles.

7. The bag of Claim 5, wherein the peelable seals form a pattern of connected rectangles.

8. The bag of Claim 6, wherein the first profile is a rib profile and the second profile is a groove profile.

9. The bag of Claim 7, wherein the first profile is a rib profile and the second profile is a groove profile.

10. A reclosable thermoplastic bag comprising: a) two opposing thermoplastic sheets, each sheet having a top edge, two side edges and a bottom edge; b) permanent seals joining the opposing sheets along the side edges and the bottom edge; c) peelable seals joining the opposing sheets at intermittent points between the side edges; and d) a fastener means positioned above the peelable seals, the fastener means being integral with the bag, the fastener means being adapted to open or reclose and providing a stiffened region.

11. The bag of Claim 10, wherein the fastener means is a plastic zipper comprising: i) a first profile positioned along the length of the top edge of one of the opposing sheets; ii) a second profile positioned along the length of the top edge of the other opposing sheet, the second profile designed to interlock with the first profile when the fastener means is closed.

12. The bag of Claim 11 , further comprising: e) filling means positioned above the plastic zipper.

13. The bag of Claim 12, wherein the filling means comprises a web of plastic extending above the plastic zipper.

14. The bag of Claim 13, wherein the web of plastic is textured.

15. The bag of Claim 14, wherein the peelable seals form a pattern of connected circles.

16. The bag of Claim 14, wherein the peelable seals form a pattern of connected rectangles.

17. The bag of Claim 15, wherein the first profile is a rib profile and the second profile is a groove profile.

18. The bag of Claim 16, wherein the first profile is a rib profile and the second profile is a groove profile.