CN1478036A - roll top bag structure - Google Patents

Abstract

A gusseted bag of disposable packaging material has a roll-top closure comprising two releasably engageable fastener components (20, 24). Each fastener component comprises a plastic base layer (52) carrying either hook or loop elements. In some cases, one component (24) is secured to one face (26) of a rollable top of the bag, and the other component is carried on a flexible flap secured to a lower portion of an opposite face (22) of the bag. In another embodiment, one fastener component (24) extends in a strip from an upper edge of the bag down one face (26) of the bag, and the other fastener component (20) extends in a strip from an upper edge of the bag down an opposite face (22), such that the top of the bag is folded downward, one fastener component (24) will engage the other fastener component (20) to hold the top closed.

Description

roll top bag structure

technical field

The present invention generally relates to bags which can be closed by folding or rolling down the top, for example for packaging granular substances and other commodity products. The present invention particularly relates to reclosable surface closures for roll top bags having gusseted edges.

Background technique

Conventional roll-top bags are closed using a surface fastener element (e.g., a portion of loop material) on the top edge of the bag's front exterior and mating fastener elements (e.g., a portion of loop material) spaced down the rear of the bag by about two fastener element widths. Hook material of a certain width). To secure the top of the bag in the rolled state, the top is folded towards the back of the bag by the width of the snap elements and then rolled again so that the engaging surfaces of the snap elements engage each other. Once engaged, the fastener elements are primarily exposed to peel loads (ie, the separation force is substantially perpendicular to the plane of the fastener elements) as the coiled top tends to open.

It has been found that hook and loop closures, as well as some bonded closures, withstand shear loads (ie, withstand a resistive load substantially parallel to the faying surfaces) better than peel loads. An improvement in roll top bag construction is proposed by Rinicker in U.S. Patent No. 3,655,118 by subjecting the hook and loop engagement to shear by having the lower surface fastener elements facing the bag face of the yielding edge. To secure the Rinicker bag closed, the top of the bag is rolled down, the edge is lifted, and the rolled top is inserted between the bag face and edge so that the hook and loop engage.

There is a need for improved closures, especially those already accommodated by modern bag making and filling equipment, which are easy to use and designed for a variety of bag configurations, such as gusseted roll-top bags for items such as coffee .

Summary of the invention

One aspect of the present invention relates to a gusseted bag of disposable packaging material having a roll top closure formed during use by two detachable engageable snap elements, one element located on the side of the bag. Wrapping the upper edge of the top, another element is located on a deformable sheet fixed to the lower part of the bag face. Each element is in the form of a plastic substrate layer carrying respectively a hook or loop element.

In a preferred structure, the deformable sheet is fixed on the pocket surface along the upper edge of the sheet, its snap elements face away from the pocket surface and the sheet sticking part is placed below the pocket surface. The top of the bag is folded down towards the flap, which is then folded up, engaging the two snap elements and securing the folded top between the bag face and the flap.

In another preferred embodiment, the deformable sheet is secured to the bag face along the upper edge of the sheet with its snap elements facing away from the bag face and placed on the bag face below where the sheet is glued, and the top of the bag is folded down onto the sheet , to engage the two snap elements. When the folded top is released and the top tends to open, the sheet flexes upward to follow the open top and reorients so that at least most of the peel load acting on the buckle is converted to a shear load.

In some preferred embodiments, the packaging material forming the gusseted bag has an outer heat-weldable plastic layer in the form of a film or coating, and the plastic matrix layer of the plastic element is made of a compatible heat-weldable material. In many preferred embodiments, the plastics of each layer are of substantially the same molecular type. In one case each layer comprises polyethylene, in another case each layer comprises polypropylene, in another case each layer comprises a copolymer of EVA and polyethylene, in another case each layer comprises polyester.

According to another set of preferred embodiments, the outer surface of the gusseted bag is formed from paper, and the snap elements have an adhesive layer, preferably in many embodiments a pressure sensitive adhesive, or in other cases a The heat activates the adhesive, and appropriate pressure and/or heat is applied during the manufacturing process to secure the elements to the bag. In a particular embodiment, the outer surface of the bag is paper and an adhesive (eg, a moisture sensitive or resin adhesive) is pre-applied to the base layer of the closure element.

In a preferred embodiment of the present invention, the loop material is a nonwoven material (eg, made of needled fibers), such as that manufactured by Velcro USA of Manchester, NH under the trademark ASPEN. Various detailed features of this preferred ring material can be found in co-pending application US No. 09/262,159, the entire contents of which are hereby incorporated by reference.

The male snap elements (ie hooks) are preferably integrally formed (ie molded) with the plastic substrate layer of the snap elements.

In some preferred embodiments, one or both of the two fastener elements are preapplied to the packaging material prior to forming the gusseted bag.

In some preferred embodiments, the two fastening elements are delivered to the bag making process as a unit (ie, as parallel sections of a wide closure strip), then separated into two elements and applied to the packaging material.

In another preferred embodiment, the closure strip forming the two elements has a divided tear strip between them, the elements are secured to the bag as a unit, the tear strip being adapted to be removed by the purchaser, separating the unit in two. a single element.

In some embodiments, the deformable sheet is secured to the pocket face along the lower edge of the sheet with the snap elements facing the pocket face so that the snap elements are engageable by moving the sheet away from the pocket face and closing the bag The top is folded down between the panel and the bag face, the sheet is then moved back to the bag face, the snap elements are engaged, and the folded top is secured between the bag face and the panel.

According to another aspect of the invention, a bag of disposable packaging material has a closure comprising two releasably engageable snap elements, wherein each snap element includes a plastic substrate layer carrying hook or loop elements. One snap element extends in a strip from the upper edge of the bag foldable top down to one side of the bag, and the other snap element extends in a strip from the upper edge of the bag foldable top down to the opposite side of the bag. One side so that when the top of the bag is folded down, one snap element will engage the other snap element to close the top.

Preferably, one or both snap elements extend from the top of the bag to the bottom of the gusset of the bag. In some cases, one of the snap elements covers the fin seal of the bag.

In some embodiments, the pocket has gusseted sides formed between the extended faces of the closure elements.

Various embodiments may also have the features described in U.S. Patent 6,202,260 and PCT Application PCT/US99/26261 published May 18, 2000 as WO 00/27721, the entire contents of which are incorporated herein by reference Documentation, as fully described.

According to another aspect of the present invention, there is provided a method of forming a bag of wrapping material having a roll-top closure, the closure comprising two releasable and engageable snap elements, each snap element comprising a hook or loop-loaded element plastic base layer. The method includes forming a roll-top bag of packaging material, a first fastening element is located on one face of the foldable top of the bag, and a sheet extending from a lower portion of the opposite face of the bag and carrying a second fastening element is positioned such that The flap may engage the first element when the top of the bag is rolled down.

In some embodiments, the method includes pre-applying the first fastening element to the packaging material and securing the sheet carrying the second fastening element to the packaging material prior to forming the roll-top bag.

In some cases, the method includes applying the two fastener elements to the bag-making process as parallel portions of an integral closure strip, dividing the closure strip into the two fastener elements, and then applying the fastener elements to the packaging material.

The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below, while other features, objects and advantages of the invention will become apparent from the description and drawings, and from the claims.

Brief description of the drawings

Figure 1 is a perspective view of a roll-top bag;

Figure 2A is an end view of the roll-top bag of Figure 1 with the top rolled up and held down, engaging the surface fastener elements;

Figure 2B shows the bag in Figure 2A with the winding top released;

Fig. 3 is a sectional view along line 3-3 in Fig. 2B;

Figure 4 is an enlarged side view of the top of the bag, with surface fastener elements installed;

Figure 5 is a perspective view of a second roll-top bag;

Figure 6 is a perspective view of the bag of Figure 5 in an unfilled state;

Figures 7A and 7B are two alternative cross-sectional views along line 7-7 in Figure 6;

Figures 8A-8C sequentially represent the opening and reclosing of the third roll-top bag structure;

Figure 9 is a transverse cross-sectional view of a first one-piece closure strip, Figure 9A showing such a closure strip installed on a bag;

Figure 10 is a transverse sectional view of a first one-piece closure strip, Figure 10A showing such a closure strip installed on a bag;

Figures 11A-11C show a bag with three different top folds.

In the different drawings, similar reference signs indicate similar elements.

Detailed description of the invention

Referring to Figure 1, a gusseted bag 10 has a substantially flat base 12 so as to stand on a horizontal support surface (not shown), such as is commonly found in coffee packaging. The main body 14 of the bag is made of a plastic film such as polyethylene (on the inside surface of the bag to promote freshness) and polyester (on the outside surface of the bag to increase durability) laminated. Lateral end seals 16 and vertical fin seals 18 form the membrane into the illustrated pouch shape with an internal cavity as shown in the view of FIG. 3 .

Referring again to FIG. 1, the bag 10 has two surface fastener elements that releasably hold the top of the bag closed and rolled for storage. A male surface fastener 20 is affixed along its upper edge to the rear face 22 of the bag, with the lower portion of the fastener 20 protruding freely from the bag over most of its area. Buckle 20 is preferably hung from a width of plastic resin shaped to have a series of integrally formed loop-engageable male buckle elements projecting from its broad outer surface. These snaps can be formed by the process described by Fisher in US Patent 4,794,028, incorporated herein by reference. In this embodiment, the fastener is used such that its longitudinal forming direction extends along the face of the bag and the hook-shaped fastener elements extend along the width of the bag. However, other shapes of male snap elements may be used, or the hooks may face upward and/or downward when used on a bag. Preferably, the buckle 20 is resin compatible with the outer surface of the bag 10 so that, for example, the upper edge of the buckle can be permanently attached to the bag by heat bonding. Other suitable bonding methods include the use of pressure sensitive adhesives (PSA) or moisture sensitive adhesives (MSA), such as resin coatings.

The female surface fastener 24 is applied to the front face 26 of the bag 10 towards the top of the bag. The buckle 24 has an engageable loop or fiber engageable with the buckle element of the buckle 20, and is permanently secured (for example by heat sealing) to the bag film along at least two long sides of the bag, preferably along the sides of the bag. The entire back (e.g. by heat sealing or adhesive). The fibers exposed on the outer surface of the buckle 24 may be, for example, the ASPEN material described above. As shown, the buckles 20 and 24 extend substantially the entire width of the bag 10 .

To close the bag 10, the top of the bag is first folded over the upper edge of the loop closure 24, as indicated by arrow A. Fold the top of the bag over again, this time just below the lower edge of the buckle 24, as indicated by arrow B. The top of the bag is then folded a third time, this time only over the upper portion, and the edges of the hook closure 20 are joined so that the exposed engagement surfaces of the closures 20 and 24 engage each other (as shown in FIG. 2A ). When the lower edge of the buckle 20 is attached to the bag face, releasing the wrapped bag top at this position will impose a normal (i.e., peel) separation load on the surface fastener because the rolled bag top is elastic and It tends to open. However, since the lower portion of the buckle 20 is not attached, the elasticity of the top of the roll-up bag will pull the buckle 20 upwards, bending around its glued upper edge, until it turns to the top of the roll-up bag and the outward surface points upward, as shown in FIG. 2B Show. It has been found that with such a thin, deformable hook base, the buckle 20 can be pulled into an orientation of 10 to 30 degrees from vertical. And the tendency of the top of the roll-up bag to open creates a load between the surface fasteners, primarily a shear load (i.e., parallel to their faying surfaces), which is a convex surface fastener that is more easily absorbed by the surface fastener than by peeling. The buckle bears the load mode. As shown in Figures 2A and 2B, after the roll-up top is released, the roll-up top's lowermost fold is almost fully unfolded, and the lower hasp 20 is rotated upwards to the direction of the shear load. It should be understood that other numbers of folds are conceivable for this general bag closure structure, the last of any such number of folds being at least partially used to draw the closure to the shear load orientation. For example, Figures 11A-11C show different numbers of folds. The more folds, the better the closure's seal.

Figure 4 shows the preferred distance between the clasps 20 and 24 to achieve the above fold. The width "W" of the loop closure 24 is about 1/2 inch (12.5 mm) and is at a distance from the upper edge 28 of the bag equal to its width minus a segment "X" of about 1/8 inch (3.2 mm). The hook and loop fastener 20 is attached to the bag surface at a position below the loop fastener 24 at a distance equal to the width "W" of the fastener 24 plus the segment "X". These pieces are used to adjust when the top of the bag is rolled, taking into account the fold thickness. The array of buckle elements on buckle 20 is also about "W" wide.

Figure 5 shows a bag 20 with a roll top closure, the function of which is that the top can be folded any number of times. This pouch configuration is particularly useful, for example, in applications where the user gradually collapses the pouch as the contents of the pouch are reduced. For example, bags for charcoal briquettes are one such application. A hook and loop fastener 24 extends vertically across the front 32 of the bag, and a hook and hook fastener (not shown in this view) engaged therewith extends in a parallel fashion across the rear 34 of the bag. When the top of the bag is folded one or more times, its two opposite sides, and the respective buckles carried thereon, engage each other to form a detachable joint. In this embodiment, the hook and loop strip is permanently bonded to the bag membrane along its entire length, ie corresponding to the entire length of the bag. It should be understood that this particular configuration does not provide the principal shear loading advantages, but many of the other advantages mentioned above.

Figure 6 shows the bag 30 in an empty and open state, eg before being filled. In order to show the longitudinal fin-like seal 18 extending in front of the bag, which is aesthetically covered by the ring element, only the ring element 24 is shown in phantom outline. The ring element 24 may be adhered with adhesive 36 to the pouch film of the longitudinal fin seal on both sides, as shown in FIG. 7A, or may be aligned on one side with the free edge of the fin seal, as shown in FIG. 7B. Both approaches have clear advantages, the snap shown in Figure 7A can be applied to the bag after the fin seal has been formed, and even after the forming and filling process is complete if desired. On the other hand, the fastener shown in Figure 7B, which is thermally bonded or welded directly to the bag film, can be applied to the film-shaped bag film prior to forming and filling the bag, and the fastener strips are delivered directly to the bag in continuous lengths. In forming equipment, or applied to the individual edges and the middle of the bag film when wound onto rolls, two preferred embodiments result.

Figures 8A-8C illustrate roll-top bag configurations combining shear loads and different adjustment capabilities. A strip of loop member 24 is permanently affixed to the front of bag 40, similar to the arrangement of the loop strips of the bag in FIG. However, at the back of the bag, the hook elements 20 are glued to the bag only at their upper and lower ends, with the array of hook elements facing downwards towards the bag film along its entire length. As shown in Figure 8A, the upper edge of the filled bag 40 is sealed to form a bag suitable for holding perishable items, and the upper seal of the bag forms a tear strip 42 which is torn from the bag when it is first opened. Hook element 20 is only combined on the tear strip 42 at its upper end, and has an upper frangible joint near the tear strip position (i.e. transverse scoring line or tear gap, not shown), so that when the tear strip is torn , the upper end of the hook element 20 is separated from the bag, as shown in FIG. 8B. To reclose the bag, the top of the bag is rolled as needed, then the stretch hook strip 20 wraps around the top of the bag (as shown in FIG. 8C ), engaging the loop strip 24 over a large area, creating the main shear load.

The two buckles can also be part of an integral strip. For example, FIG. 9 shows a closure strip 50 having a unitary resin matrix 52 with tear ribs 54 and integrally formed snap elements 56 extending parallel thereon, a loop material 58 also on the matrix, the fibers of the loop material Embedded and fixed in the resin of the matrix. Methods of forming such integral closure strips are described in more detail in US Patent No. 6,202,260. Parallel, continuous strips of adhesive 60 are attached to the back of the closure strip for securing the closure strip to the bag, eg, as shown in Figure 9A. A narrow strip of adhesive 60 on the hook side of the tear rib 54 adheres the closure strip to the bag face, while a wide strip of adhesive 60 on the loop side of the rib 54 adheres the closure strip to the rolled top of the bag after filling . When the closure strip is so applied to the bag, the closure strip 50 provides the desired secure closure feature because the bag cannot be opened without breaking or tearing the closure strip. To open the bag, the closed base 52 is torn into two parallel parts, each with a respective one of the engageable snaps, grasping the tear rib 54 and pulling it over the face of the bag and discarding it. Base body 52 has formed tear grooves (not shown) on each side of rib 54 to help control opening of the bag. The bag can thereafter be reclosed, as described above, by rolling the top of the bag down to engage the two snaps. Since the lower edge of the closure strip 50 is not glued to the bag, the lower snap element is free to hinge on its corresponding adhesive glued to the bag face so that the orientation of the engaging face is in the direction of the shear load.

Figure 10 shows another embodiment of an integral closure strip 70 for a roll top bag. In this embodiment, the formed male snap element 56 is formed on the side opposite to the side carrying the tear rib 54 and loop material 58 . Underneath the loop material is a wide band of adhesive 60 and under the adjacent longitudinal edges of the hook elements is a narrow band of adhesive 60 . A narrow strip of adhesive secures the lowermost edge of the bag closure 70 to the bag face with the hook elements 56 facing the bag film, as shown in Figure 10A. A wide band of adhesive 60 permanently secures the closure strip to the rolled or folded top of the filled bag. When opening the stuffed bag for the first time, grasp the tear rib 54 and pull to tear the closed substrate. Thereafter, the bag can be reclosed by compressing the rolled top between the bag face and the lower closure hook portion formed by tearing. Although this closing sequence requires simultaneous operation of the hook portion and the winding top, typically requiring two hands, it can provide the aforementioned shear load advantages. Also, the integral nature of the closure strip eases assembly and provides a secure closure feature. Since the closure is glued to the top of the bag only after filling, the loop elements can be positioned according to the actual needs of each filled bag. In this way, the upper part of the closure can advantageously be glued to the filled bag, which has been rolled down into a very tight, space-reducing position, and the closure is in tension, like a strip of glue. Bonding tape. Such tight packaging is desirable to remove air, enhance sealing (eg, for perishable items), and reduce shipping and storage space for retail merchandise.

For example, the adhesive 60 on the underside of each closure strip in the bags shown in Figures 9A and 10A could be replaced by heat welding. In this case, a closure strip can be applied to the bag prior to filling. The closure strip can be provided in continuous form and cut to length for the application, or cut to length with a release line and bonded to the bag using conventional labeling equipment.

It should be realized that the above-mentioned drawings are not intended to be limiting, but rather to schematically represent the concepts of the claims. For example, the closure elements described above typically have a base thickness of only about 0.003 to 0.007 inches (preferably between about 0.004 and 0.005 inches), but the figures shown appear to be much thicker than the bag film, which is preferably Has the same thickness as the closed base. The thin and deformable closure matrix, especially for the bag structure shown in Figure 1 and compared to the bag film itself, makes it easier for the lower closure element to pull upwards in the direction of the shear load. Thicker bag films have greater elasticity, providing greater recovery of the wrap top for closed reorientation. The thin closure also enables the use of standard handling and packaging equipment.

While a number of embodiments of the invention have been described, it should be understood that various modifications may be made without departing from the spirit and scope of the invention. Accordingly, other implementations are within the scope of the following claims.

Claims (26)

1. one kind has the closed packing timber the abandoned pocket (14) in volume top, and this closure comprises two the engaged hasp elements (20,24 that can take apart; 56,58), wherein,

Each hasp comprises and is loaded with the plastic substrate layer (52) that colludes element or loop member,

One of them hasp element (24,58) is fixed on bag and can reels on the one side (26) at top, is fixed on the lower part of a bag reverse side (22) at another hasp element on the deformable sheet.

2. bag as claimed in claim 1, it is characterized in that the deformable sheet is fixed on the reverse side (22) of bag along its upper limb, its hasp element (20,56) towards the direction of leaving bag reverse side and be positioned at the upper limb below of sheet, thereby the hasp element can engage, and the top that is about to bag is folding downwards towards sheet, and pleated sheet then makes progress, so that two hasp elements engage, and will fold the top and be fixed between bag reverse side and the sheet.

3. bag as claimed in claim 1, it is characterized in that the deformable sheet is fixed on bag reverse side (22) along its upper limb, its hasp element (20,56) towards the direction of leaving bag reverse side and be placed on below the sheet location for paste on bag reverse side, and the top of bag folds on the sheet downwards, so that two hasp elements engage.

4. bag as claimed in claim 3 is characterized in that hasp element (20,24; 56,58) can change of direction, when decontroling folding top and top and be tending towards opening, the sheet K/UP is transformed into shearing load to follow opening of top, to make the most of at least peeling load that acts on the closure.

5. as each described bag of above-mentioned claim, but the packing that it is characterized in that forming angle brace limit bag have the skin of the heatsealing plastics of film or coating form, the plastic substrate layer (52) of hasp element but make by the material of compatible heatsealing.

6. bag as claimed in claim 5 is characterized in that packing plastics outer and base layer (52) have essentially identical molecule type.

7. bag as claimed in claim 5 is characterized in that packing outer layer plastic and base layer plastics (52) all comprise polyethylene for every layer.

8. bag as claimed in claim 5 is characterized in that packing outer layer plastic and base layer plastics (52) all comprise polypropylene for every layer.

9. bag as claimed in claim 5 is characterized in that packing outer layer plastic and base layer plastics (52) all comprise EVA and poly copolymer for every layer.

10. bag as claimed in claim 5 is characterized in that packing outer layer plastic and base layer plastics (52) all comprise polyester for every layer.

11., it is characterized in that the outside face of angle brace limit bag is formed by paper as each described bag of above-mentioned claim, have adhesive layer (60) on the hasp element, the hasp element is fixed on the paper of bag outside face.

12. bag as claimed in claim 11 is characterized in that adhesive layer (60) comprises pressure sensitive adhesives.

13. bag as claimed in claim 11 is characterized in that adhesive layer (60) comprises the hot activation adhesive agent.

14. bag as claimed in claim 11 is characterized in that adhesive layer (60) comprises wet quick adhesive agent.

15., it is characterized in that loop member is the on-woven ring material as each described bag of above-mentioned claim.

16. as each described bag of above-mentioned claim, it is characterized in that colluding element and be Unitarily molded the forming of resin with the plastic substrate layer (52) of one of them hasp element (20,56).

17. as each described bag of above-mentioned claim, comprise closure strip (50,70) that forms two hasp elements (56,58) and the tear band that separates, tear band is between the hasp element and be suitable for removal, closure strip is divided into independent hasp element.

18. as each described bag of above-mentioned claim, it is characterized in that the deformable sheet is fixed on bag reverse side (22) along its lower edge, its hasp element (20,56) towards bag reverse side (22), thereby the hasp element can engage, and its process is a moving sheet with away from the bag reverse side, the bag top is folded into downwards between sheet and the bag reverse side, then moving sheet makes it turn back to a bag reverse side, and the hasp element is engaged, and folding top is fixed between bag reverse side and the sheet.

19. one kind has closed disposable packaging material bag, this closure comprises two knock-down hasp elements (20,24) that engage, wherein,

Each hasp element comprises and is loaded with the plastic substrate layer that colludes element or loop member,

One of them hasp element (24) extends downwardly into a face (26) of bag from the upper limb at the collapsible top of bag with strips, and another hasp element (20) extends downwardly into a bag reverse side (22) with strips from the upper limb at the collapsible top of bag, thereby when the top of bag is folding downwards, a hasp element (24) will engage with another hasp element (20), so that the top closure.

20. bag as claimed in claim 19 is characterized in that at least one hasp element (20,24) extends to the bottom, angle brace limit (12) of bag from the top of bag.

21. bag as claimed in claim 19 is characterized in that two hasp elements (20,24) all extend to the bottom, angle brace limit (12) of bag from the top of bag.

22. bag as claimed in claim 19 is characterized in that one of them hasp element (24) covers the fin-shaped sealing (18) of bag.

23. bag as claimed in claim 19 has the side on angle brace limit, is formed between the face (22,26), hasp element (20,24) extends along described side.

24. a formation has the method for the closed packing timber pocket in volume top, this closure comprises two the engaged hasp elements (20,24) that can take apart, and each hasp element comprises and be loaded with the plastic substrate layer that colludes element or loop member that described method comprises:

Form the volume top bag of packing, the first hasp element (24) is positioned on the face (26) at the collapsible top of bag, and sheet extends from the lower part of bag reverse side (22) and is loaded with the second hasp element (20), can engage with first element (24) when reeled downwards at the bag top in the position of the second hasp element (20).

25. method as claimed in claim 24 comprises: before forming volume top bag,

Be applied to the first hasp element (24) on the packing in advance; And

Sheet is fixed on the packing, and this sheet is loaded with the second hasp element (20).

26. method as claimed in claim 24 comprises:

With two hasp elements (56,58) as a whole the parallel portion of closure strip (50,70) be applied to the bag process;

Closure strip is divided into two hasp elements (56,58); Then

With the hasp element application to packing.

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