Integral reclosable bag

Beginning of the patent period: December 15, 1965.

The invention relates to a plastic bag in one piece with a profile strip closure, in particular for packaging purposes, in which the approximately perpendicular to the bag walls, each other inside the bag interior profile strips are brought to the closure of the bag in mutual engagement, wherein attached to the one bag wall closure profile strip has a ver5 thickened outer edge and the other forms a correspondingly shaped groove.

In a plastic bag of this type, it is known to give the thickened edge of a profile strip a substantially circular cross-section and thus form the counter profile in the groove strip also circular in cross section.

The resistance that the closure opposes to a force exerted by the contents of the bag from the inside 10 force is therefore equal to the force that is used for the opening of the bag from the outside. This is undesirable, since an inherently desirable high resistance to opening from the inside is just as great a resistance that is used for the opening of the bag from the outside.

However, this disadvantage is eliminated if, according to the invention, the thickened outer edge in the cross section has, in a manner known per se, the form of an unsymmetrical arrow whose outwardly directed, lateral projection is shorter and / or less inclined to the associated bag wall than the other, the bag bottom facing lateral projection, and the groove walls have the shape of directed towards the Nutinneren hook, their undercut hook surfaces correspond in length and inclination to the length and inclination of the arrow projections.

The inventively designed plastic bag sets a force exerted by the contents of the bag from the inside force greater resistance than the opening by a force acting from the outside force. In this way, the bag is easy to open and yet able to provide a great resistance to a pressure exerted by the filled material on the closure pressure.

When zippers, it is now known to give one of the mutually engageable profile strips 25 in cross section the shape of a single-ended arrow. Such zippers, however, can not lead to a bag, since the arrow-shaped profile strip would in any case lie in the extension of a possibly provided bag wall, rather than perpendicular abzustfehen from this. The bag and its closure could thus by no means be made of a plastic tube having the bag wall and closure strips and also not fulfill the purpose of the invention.

According to a further embodiment, in the plastic bag according to the invention, the profile strip having the groove has a claw-like shape, wherein its width at the point where it merges into the associated bag wall, has a minimum value and widened after the free ends of its side walls formed as hooks These side walls preferably have a curved cross-sectional shape. By this embodiment of the invention it is achieved that a force which is directed to a spreading of the walls equipped with the closure profiles, a resultant, which causes an approximation of the hook surfaces of the groove against each other by these hook surfaces between them the web

No. 248947 of the opposite profiled strip and act in a way like the jaws of a pair of pliers.

Further advantageous features of the invention are set forth below in the description with reference to the drawings.

Fig. 1 of these drawings shows in cross-section and on a greatly enlarged scale part of a bag with a closure according to the invention of a rib and a fold. Figs. 2, 3 and 4 show three different embodiments of closure elements in the form of ribs and folds. In Fig. 5 is a perspective view of a tubular web is provided which is provided with a rib and a Verschlußfalz and is used for the production of bags according to the invention. FIG. 6 Figure 5 shows the tubular web of Figure 5 flattened, with the rib and fold engaged. Fig. 7 is a perspective view of the production of the individual pockets of the flattened tubular web of FIG. 6 again. In Fig. 8th is a perspective view of a provided with a rib and a shutter fold flat web whose rib and fold lie on both sides and in the vicinity of a center line, which is used for the production of bags according to the invention. Fig. 9 shows the flat web of Fig. 7, folded along its center line, with interlocking rib and fold intermeshing. FIG. 10 FIG. 10 illustrates a flat web provided with a closure rib and a closure fold located near the edges of the web, which is also intended for the manufacture of bags according to the invention. Finally, Fig. 11 shows the flat web of Fig. 9 folded along its center line, with the interlocking rib and fold interlocking.

The walls 1 and 2 of the bag according to the invention consist of a web or Plastic film, which is provided near its edge between the opposite inner sides of its walls 1 and 2 with interlocking trained profile strips for closing the bag, which can be pressed together by a simple finger pressure - taking into account the tear strength of the walls 1 and 2 - the inner pressure of the contents of the bag against the walls 1 and 2 provide sufficient resistance, in order to be able to retain this content completely safely, however, they can be separated from one another by means of a simple finger pull on the opening tabs 1a and 2a of the walls 1 and 2 except for the profile strips (FIG.

The resistance which the profile strips oppose to separation due to an internal pressure of the pocket is several times, preferably approximately five times, greater than the force required to exert an influence on the opening tabs 1a and 2a of the pocket walls 1, 2 from the outside to effect their interlocking or separation.

Advantageously, the training is carried out in such a way that the resistance of the moldings against their separation due to the pressure that the contents of the bag from the inside against the walls 1 and 2, for example in the event of a shock, squeezing or falling of the bag, exercise, the tensile strength of walls 1 and 2 is at least equal to or exceeds them.

The spring and the groove are formed with corresponding shapes so that they are respectively engaged on both sides of their axial surface XY, which is perpendicular to the associated wall 1 or 2 of the pocket (Figure 2), by their shapes and / or dimensions different engagement profiles which, because of this difference, is most suitable for intermeshing with respect to the profile

Level XY comes to rest on the inside of the bag.

The arrow-shaped profile strip 3, 4 has a head 4, which is connected by means of a web 3 with the wall 1 of the bag and its lying on both sides of the web 3 coming projections 8,9 are arranged asymmetrically and undercut hook surfaces 5 and 6 of the Groove offer 7 engagement surfaces. That projection 8, which extends from the web 3 towards the interior of the pocket, runs obliquely against the wall 1 of the pocket, whereas that projection 9 which extends from the pocket

Ridge 3 extends to the outside, parallel to this wall or approximately parallel.

The groove 7 may have between the hook surfaces 5 and 6 a profile in the form of a circular or elliptical arc or in the form of a polygon.

The groove 7 is provided in a profile strip 10 which forms a kind of channel and is connected by its bottom 50 a along its median plane XY to the wall 2 of the pocket and on this

Wall a projection against the arrow-shaped profile strip 3, 4 of the other wall 1 forms.

On each side of the arrow-shaped profile strip 3, 4 a strip 11 (FIG. 3) can be provided, which can support the profile strip 10 against the arrow-shaped profile strip 3, 4.

According to another embodiment shown in Fig. 4, the groove 7a is bounded by two parallel 55 rails 10b and 10c which protrude from the wall 2 of the pocket.

Advantageously, the groove forming profile strip 10 (or the rails 10b and 10c) bestentent

No. 248947 of the same material as the wall 2 applies to the arrow-shaped profile strip 3, bag.

In this case, the walls of the bag and with this wall consist of one piece; the same 4 (and optionally strips 11) and the wall 1 of (Fig. 5) and on the 7 having profile Then the tube 12 and 2 of the pocket and the arrow-shaped profile strip 3, 4, 5 as well as the walls of the groove 7 from a single piece obtained by extrusion.

In the preparation can be proceeded in various ways.

After a first operation is produced by extruding a tube inside this tube, the arrow-shaped profile strip 3, 4 and the groove strip 10, wherein spring and groove are adjacent to each other parallel to the pressing axis.

flattened, with the spring inserted into the groove (Figure 6). Finally, the tube 12 is divided into sections 12a, 12b, 12c, 12d, etc. (Fig. 7), which are closed at their ends 13 by welding and then opened above the closure at 14.

According to another method, a flat band 15 (Fig. 8) is produced by pressing, which contains the profile strip 3, 4 and the groove 7 having profiled strip 10, these two Profillei15 costs on both sides and in the vicinity of the center line M._t - M_G of the band are arranged. Then the tape along the line Μ_χ - M_G folded, wherein the profiled strip 3, 4 is inserted into the groove 7 (Fig. 9), and finally from it pieces are cut, which are different from the pieces of FIG. 7 in that they at 16, on the opposite side of the closure elements , are open. The opening 16 may serve to fill the pocket and then verschlos20 sen by welding.

According to another embodiment, the arrow-shaped profiled strip 3, 4 and the profiled strip 10 provided with the groove 7 can be provided parallel and at a short distance from the edges of a flat web 15a obtained by pressing (FIG. 10). Then, the web 15a is folded along its center line and the spring is inserted into the groove (Figure 11). Then you can from the train

Cut off pieces that differ from the pieces of FIG. 7 in that they are already open at 14.

When proceeding in the manner illustrated by Figures 5-7 or Figures 8 and 9, it may be advantageous not to open the pockets at 14 and to use the wall of the bag at this point as an additional closure or warranty strip, which one must cut or tear to get access to the actual closure elements and to Inhalc the bag access.

In this case, it is best, in the course of the pressing process, in the part of the web 15 (Fig. 8) extending between the fastener elements on the side opposite the actual pocket, to provide two weakening grooves 17 which are equidistant from the center line Μ_χ - M₂ the railway are located. These two grooves 17, when the web is folded 35, lie over one another, as shown in Fig. 9, and form a preferable tear line to the tearing of a strip between the arrow-shaped profile strip 3,4 and the groove. 7 of the closure, whereby the closure, as shown in Fig. 11 at 14, is accessible from the outside.

It will be understood that, if one wishes to open the bag by exerting in the opposite sense a pull on the opening tabs 1a and 2a of the bag in the direction XY (Figure 1), the edges 6 and 9 through which the groove 7 and the arrow-shaped profile strip 3, 4 from the side interaction, which faces in relation to the plane XY the bag formed by the bag, only a small resistance.

However, as soon as the edge of the outwardly directed lateral projection 9 of the arrow-shaped profile strip 3, 4 has left the groove 7, the lateral projection 8 of the profile strip 3, 4 facing the bottom of the bag can be easily detached from the edge 5 of the profile strip 10 by turning the arrow-shaped profile strip in the groove.

On the other hand, if the contents tend to spread apart the side walls 1 and 2 from the inside of the bag, the two interacting moldings remain deep with a strong one

Adhesion tendency interlock, anchored in each other.

The cohesion is even firmer from the inside of the bag when you let the head 4 on the web 3 of the profile strip more protrude against the inside than against the outside of the bag, that is, the excess material thickness of the plane XY after Irftieren the bag extends over a distance A which is greater than the distance B, over which the same excess material thickness extends from the plane XY to the outside of the pocket.

According to the shape of the arrow-shaped profile strip 3.4 lends the hook surface 5, the

No. 248947, the groove 7 narrows, a larger'length than the hook surface 6. If you want to close the bag again, it is sufficient to press with your fingers from the outside against the walls 1 and 2 along the plane XY, so that the arrow-shaped profile strip 3, 4 engages in the groove 7, wherein the walls of the groove 7 having profiled strip 10 are resiliently pressed apart.

If you want to produce a bag whose walls 1 and 2 consist of a single piece with the moldings 3, 4 and 10, you must, in order to achieve optimum resistance, the dimensions of the arrow-shaped profile strip and the groove having the second profile strip in proportion to select the thickness of the walls 1 and 2 of the bag.

The closure must have the desired resistance to opening while being as small in size and weight as possible.

Assuming that the bag is to be made of polyethylene, it is to be assumed that a common quality web for the present package has the following resistance properties depending on its thickness:

<td>Example no.</td><td>1</td><td>2</td><td>3</td><td>4</td><td>5</td>

<td>Thickness in mm</td><td>0.03</td><td>0.04</td><td>0.05</td><td>0.06</td><td>0.07</td>

<td>Tensile resistance in kg / 20 cm</td><td>1.</td><td>1.3</td><td>1.6</td><td>2</td><td>2.35</td>

<td>Dielectric strength against a falling weight</td><td>80</td><td>110</td><td>150</td><td>200</td><td>260</td>

This table shows that the resistance of the sheet or foil, from which the walls 1 and 2 of the pocket should consist, is proportional to their strength.

It was found by experiments that the closure by a force of 200 to 800 g (maximum), must be open. It follows that one can then use a polyethylene film of only 0.03 mm thickness, the resistance of which is 1000 g, as shown in the table above.

Experiments have shown that a closure which opposes a random opening caused by the contents of the bag to a resistance of about 2000 g and which can be opened or closed as desired by an external force of about 400 g for one Bag is suitable, which consists of a polyethylene film of 0.05 mm thickness, whose Zugwidersjand

1600 g is. In this case, one obtains a closure whose weight and cross-section are minimal and yet fully satisfies the user of the bag. In this case, then weigh the arrow-shaped profile strip 3, 4 and the groove 7 having profiled strip 10 about 1.2 g per meter in length, and the distance between the outer sides of the walls 1 and 2 of the bag at the location of the closure from each other is approximately 1.14 mm or 17/15 mm.

The arrow-shaped profile strip of this closure has the following properties: With respect to the median plane XY, which is perpendicular to the wall 1, the lateral projection 8 facing the bag bottom forms an angle α of 55 to 65 °, the outwardly directed lateral projection 9 of the arrow-shaped profile strip forms an angle β of 80 to 90 °, while the two surfaces which delimit the head 4 of the profile strip from the outside, with the axis XY each include an angle of 35 ° to 45 °. The thickness of the web 3 of the profiled strip is about 5/15 mm and that of the head 4, at the location of the projections 8 and 9, about 10/15 mm. The tip of the head 4 of the arrow-shaped profile strip is located at a distance of about 13/15 mm from the wall 1 and at a distance of about 6/15 mm from the projection 8. The intersection of the projections 8 and 9 with the center line XY from the end of the projection 8 about 3/15 mm away.

The groove of the closure has the following properties: The thickness of the Pro3 3 filleiste between the inner wall and the outer side is about mm. The distance between the hook surfaces 5 and 6 is about 7/15 mm, their distance from the bottom of the fold about 8/15 mm.

The dimensions and angles given above for the case of a film or web of 0.05 mm thickness (Example 3) determine the relationships and shapes of general validity, ie they also apply to bags whose walls have a different thickness to have.

No. 248947

The resistance to opening the shutter changes in proportion to its weight per meter of length. Thus, the following table can be set up:

<td>Example no.</td><td>1</td><td>2</td><td>3</td><td>4</td><td>5</td>

<td>Weight of the closure profiles in g / m</td><td>0.6</td><td>0.9</td><td>1.2</td><td>1.5</td><td>1.8</td>

<td>Draw resistance in kg / 20 mm / m Inside: Outside:</td><td>1 0.2</td><td>1.5 0.3</td><td>2 0.4</td><td>2.5 0.5</td><td>3 0.6</td>

In this table, the term inside refers to the inner, the designation outside 5 to the outer parts of the bag. The values ​​given may be considered to be those which represent the maximum effort required to open the pocket, be it from the inside or outside, that is to say correspond to the force required, either the projection S and the hook surface 5 or Projection 9 and the hook surface 6 to separate from each other (Fig. 2) by exerting a pull on the walls 1 and 2 of the pocket (Fig. 1) in the opposite sense either below or above the plane XY (see the position of this plane in Fig. 1).

Advantageously, for the web or film thicknesses indicated in the first table, which have been designated by different example numbers, the closure elements listed in the second table, which are provided with the same example numbers, are used. Thus, one can use a closure according to Example No. 1, which has a weight of 0.6 g / m, with a polyethylene film according to Example No. 1, which has a thickness of 0.03 mm. In the combinations proposed in this way, the closure has sufficient support yet has a minimum weight for a given thickness of the polyethylene sheet, and one can be sure that the ratio between the outer and inner resistance is about 1 : 5 is.

The bag according to the invention could, of course, also be provided with a closure, the interlocking profile strips of which deviate from the proposed shapes of the spring and groove shown in the drawings. Provided, however, that the closure opposes the opening from the inside a resistance which is a multiple of the resistance to opening from the outside, the resistance of the walls of the bag must be higher than the latter, but preferably should be less than the former Resistance.