RU2427516C2 - Sealed throw-away one-portion container - Google Patents

Abstract

FIELD: transport, package.

SUBSTANCE: invention relates to throw-away package of sauce, mayonnaise or liquid soap. Container comprises first sheet from semi-rigid plastic material, second sheet from flexible plastic material superimposed on said first sheet and sealed thereto to form tight chamber for product. Container has notch formed in first sheet to allows controlled breakage of first sheet along said notch and produce product outlet through first sheet. Said notch features depth varying over length to allow gradual folding of said sheet.

EFFECT: adjusted product feed.

15 cl, 16 dwg, 2 tbl

Description

FIELD OF TECHNICAL APPLICATION

This invention relates to a sealed breakable container for a single dose.

BACKGROUND OF THE INVENTION

A single-dose sealed container is typically a sealed sachet bag having a sealed internal cavity containing a dose of a liquid consistency product (e.g., ketchup sauce or liquid detergent) or a creamy product (e.g., mayonnaise sauce or skin cream) . The sachet is opened by a gap and for this purpose has a small incision to facilitate tearing.

However, it is quite difficult to make sachets opened by rupture, which are both easy to open (that is, require a little effort) and strong enough to prevent their accidental opening (which leads to difficult to eliminate contamination with the product contained in these sachets). In addition, there is a problem with the use of sachets for detergents (soaps, bath foams or for washing, shampoo), which are usually opened with wet hands, in which case it is more difficult to grab the bags and hold them in your hands. In addition, the sachets of the aforementioned type opened by rupture are unsanitary for the reason that when the sachet is opened, the product inevitably comes into contact with the outer surface of the sachet near the rupture line (this obviously applies only to food).

To eliminate the aforementioned disadvantages, it was proposed to open the container by the method of breaking, as opposed to opening the package by breaking. One example of a sealed breakable single dose container is illustrated in US Pat. No. 6,041,930 B1, which describes a container formed from a sheet of semi-rigid plastic and a sheet of flexible plastic superimposed and sealed to form a sealed cavity containing a dose of the product; the semi-rigid plastic sheet has a straight central notch in order to guide the controlled fracture of this sheet. In actual use, to open the bag, the consumer simply takes the bag with the fingers of one hand and bends it to break a sheet of semi-rigid plastic over the notch. After such an operation, the product easily and hygienically flows out of the bag without contacting the outer surface of the bag.

However, in the case of a sealed breakable single dose container, such as described in US Pat. No. 6,041,930 B1, the product flows out extremely quickly and it is not possible to control the flow of the product, especially if the product is liquid (i.e. has a low density). This disadvantage is mainly due to the fact that the sheet of semi-rigid plastic instantly breaks practically along the entire notch, thus forming a very large outlet.

As a result of solving this problem, that is, the problem of providing a more controlled outflow of the product, a V-shaped notch was proposed, as described in US patent No. 6945391 B2. In this case, breaking the sheet of semi-rigid plastic should be limited at the initial moment to the central part of the notch (i.e., the top of the letter V) and then spread along the rest of the notch so that the consumer can interrupt further fracture and, therefore, can provide a small outlet bounded by the central part notch. However, numerous tests show that the solution proposed in US patent No. 6945391 B2, also not able to effectively solve the problem of controlling the flow of the product in a simple and intuitive way, especially in the case of using a liquid product.

For the manufacture of an airtight breakable container for a single dose, US Pat. No. 6,041,930 B1 proposes a packaging installation in which a semi-rigid plastic tape and a flexible plastic tape are unwound from respective rolls and stacked on top of each other in the first longitudinal sealing section, where the metering device delivers the product between two tapes which are then immediately hermetically connected from the sides in the longitudinal (i.e. parallel to the tapes) direction, forming a tube containing the product. In the transverse sealing section, following the longitudinal sealing section, the tapes are tightly connected in the transverse (i.e. perpendicular to the tapes) direction, with the formation of a plurality of containers from the tube, each of which contains a dose of the product. Finally, behind the transverse sealing section, there is a cutting section in which the tapes are cut across and the sealed containers are sequentially separated.

Sealed single dose containers manufactured on the packaging unit described above are, however, of poor quality due to poor transverse sealing and high air content. It should be noted that a large amount of air in an airtight container for a single dose seriously affects the appearance of the package and, in the case of food, significantly reduces the shelf life of the product.

DESCRIPTION OF THE INVENTION

The purpose of this invention is to provide such a sealed breakable container for a single dose, which would eliminate the aforementioned disadvantages and which, in particular, would be cheap and easy to manufacture.

The present invention provides a sealed breakable single dose container as described in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Below are described several non-limiting design options of the present invention, by examples and with reference to the accompanying drawings, in which:

Figure 1 presents a perspective top view of the proposed sealed breakable container for a single dose;

Figure 2 presents a perspective view from below of the container depicted in figure 1;

Figure 3 presents a cross section along the notch of the container depicted in figure 1;

Figures 4-8 show cross-sections along the notch of various embodiments of the container of Figure 1;

Figure 9 presents a top view of a variant of the container depicted in figure 1;

Figure 10 presents the cross section of the container element shown in figure 9;

Figure 11 presents a schematic front view of the proposed packaging installation for the manufacture of the container shown in figure 1, in which some details are removed for clarity;

On Fig presents a schematic spatial image of the section forming the incision of the packaging installation shown in Fig.11, in which some details are removed for clarity;

FIG. 13 is a schematic front view of the notch forming section of FIG. 12, in which some details are removed for clarity;

On Fig presents a schematic spatial image of the sealing section of the packaging installation shown in Fig.11, in which some details are removed for clarity;

FIG. 15 is a schematic front view of the sealing section of FIG. 14, in which some details are removed for clarity;

FIG. 16 is a schematic side view of the sealing section of FIG. 14, in which some details are removed for clarity.

PREFERRED EMBODIMENTS FOR CARRYING OUT THE INVENTION

The numbers 1 in FIGS. 1 and 2 generally indicate a sealed breakable container for a single dose. The container 1 consists of a rectangular sheet 2 of semi-rigid plastic and a sheet 3 of flexible plastic, superimposed on the sheet 2 and hermetically connected to it to form a sealed cavity 4, which will contain a dose of the product 5 (liquid, paste or powder).

The semi-rigid plastic sheet 2 has a central notch 6 extending across the sheet 2 (i.e. parallel to the short side of the sheet 2) to provide a controlled break of the sheet 2 along the notch 6 and to form an outlet for discharging the product 5 through the sheet 2. In other words, in actual use to open the container 1, the consumer simply takes it with the fingers of one hand and bends to break the sheet 2 of semi-rigid plastic along the notch 6 so that the product 5 flows out uniformly and hygienically from the container 1, does not activating with the outer surface of the container 1 (i.e., sheet 2).

As shown in FIGS. 3-8, the notch 6 has a different depth along the length so that the sheet 2 breaks along the notch 6 gradually. In particular, the notch 6 has the greatest depth in its central part. In other words, the fracture of sheet 2 along the notch 6 is always gradual, that is, proportional to the degree of folding of the container 1, so that when the container 1 is relatively slightly bent, the sheet 2 only breaks in the central part of the notch 6, and when the container 1 is bent further, the fracture of the sheet 2 extends to the peripheral sections of the notch 6.

3 and 7, the notch 6 has a V-shaped cross section.

4 and 8, the notch 6 has a W-shaped cross section.

5 and 6, the notch 6 has a constant first depth of one magnitude in the peripheral parts and a constant second depth greater than the first depth in the central part.

Figures 3, 4, 6, and 8 show an incision 6 formed symmetrically on both sides of the semi-rigid plastic sheet 2. Alternatively, FIGS. 5 and 7 show an incision 6 formed on only one side of sheet 2.

In a preferred non-limiting embodiment, sheet 2 is a laminate (laminate) and consists of a first, outer, backing layer and an inner thermally sealed second layer (i.e., contact sheet 3 of flexible plastic). Between the support layer and the thermally sealed layer, additional insulating or barrier layers may be provided to ensure impermeability to air and / or light.

The support layer of sheet 2 can be made of one of the following materials: polystyrene (PS), polyvinyl chloride (PVC), a copolymer of acrylonitrile butadiene and styrene (ABS), amorphous polyethylene terephthalate (ARET) or polypropylene (PP) and has a thickness in the range of 300-700 micron.

The heat-sealing layer of sheet 2 can be made of one of the following materials: polyethylene (PE) or polypropylene (PP) and has a thickness in the range of 20-50 microns.

Table 1 below shows the possible combinations of materials and sheet thicknesses 2.

TABLE 1 Semi-rigid plastic sheet 2 Laminate Type Thickness (micron) PS-PE PS 300-700 PE 20-50 PS-PP PS 300-700 PP 20-50 PVC-PE PVC 300-700 PE 20-50 ABS-RE ABS 300-700 PE 20-50 ARET-RE ARET 300-700 PE 20-50 PP-RE PP 300-700 PE 20-50

In a preferred embodiment, the backing layer of sheet 2 is a 450 μm layer of polystyrene (PP), and the heat-sealing layer of sheet 2 is a 35 μm layer of polyethylene (PE). Moreover, sheet 2 has a thickness of approximately 485 microns, a typical specific gravity of about 500 g / m ² , a typical fracture limit of about 16 N / mm ^2, and a typical modulus of elasticity of about 2200 N / mm ² .

In a preferred non-limiting embodiment, the flexible plastic sheet 3 is a laminate of two, three or four layers.

The layers of sheet 3 are made of: polyethylene terephthalate (PET), polyethylene (PE), polyethylene with a protective layer (PE BARRIER), metallized polyethylene terephthalate (PETM), aluminum (ALU), oriented polypropylene (OPP), oriented polyamide (OPA).

Table 2 below shows possible combinations of materials and thicknesses of sheet 3 of flexible plastic.

TABLE 2 Flexible plastic sheet 3 Laminate Type Thickness (micron) PET-PE PET 12-30 / RE 20-150 PET-PE BARRIERA PET 12-30 / PE 30-150 PET BARRIERA-RE PET 12-30 / RE 20-150 PET-RETM-RE PET 12-30 / PETM 12-23 / PE 20-150 PET-ALU-PE PET 12-30 / ALU 6-30 / PE 20-150 OPP-ALU-PE OPP 15-3 / ALU 6-30 / PE 20-150 OPA-ALU-RE OPA 15-30 / ALU 6-30 / PE 20-150 PET-ALU-PET-RE PET 12-30 / ALU 6-30 / PE 20-150 PET-PET BARRIERA-RE PET 12-30 / PET BARR 12-30 / PE 20-150 PET-ALU-OPA-PE PET 12-30 / OPA 15-30 / ALU 6-30 / PE 20-150

In a preferred non-limiting embodiment, the maximum notch depth 6 of sheet 2 is in the range of 75-150 microns and is, for example, 100 microns; the difference between the maximum and minimum notch depth 6 is in the range of 50-150 microns and is, for example, 100 microns.

In the design options shown in the accompanying drawings, the notch 6 is straight and parallel to the short side of the sheet 2. In other, not shown, designs 6, the notch 6 may be made differently, for example, may be curved (in the form of a circular arc or an ellipse arc ) can either be V-shaped, U-shaped or L-shaped. In other, not shown, design options, the notch 6 may be angled, that is, it may have a slope relative to the sides of the sheet 2.

In one of the possible designs shown in Figs. 9 and 10, sections of sheets 2 and 3 are thermally sealed with each other and surround cavity 4 (in the form of a rectangular border), having a knurling in the upper part (i.e., on sheet 3). The knurling consists of ribs running parallel to the short side of the container 1. Each rib is usually 0.20 mm high (generally 0.10 to 0.30 mm) and has a triangular cross section (i.e., an inverted V-shape) contour), with an apex angle of usually 60 ° (generally 45-75 °). The pitch between the ribs is usually 1.5 mm (in general, 1 -2 mm).

It should be noted that the knurling on the parallel short sides of the sections of sheets 2 and 3 surrounding the cavity 4 may differ from that perpendicular to the short sides of the knurling on the parallel long sides of the sections of sheets 2 and 3 surrounding the cavity 4.

Knurling of the thermo-sealed sections of sheets 2 and 3 surrounding the cavity 4 serves to strengthen the seam of thermal sealing and, thus, prevent its delamination over time (especially when cavity 4 contains an aggressive product 5).

The container 1 described above has numerous advantages: it is cheap and easy to manufacture and at the same time allows simple, intuitive control of the flow of product 5. In particular, a simple control of the flow of product 5 is achieved due to the difference in the thickness of the notch 6, along which the fault is carried out sheet 2, which is initially bounded by the central part of the notch 6, and only then spreads over the rest of the notch 6. Thus, in sheet 2, it is easy and intuitive to create a small fault that forms aloe outlet through which product 5 will flow out slowly. Obviously, the rapid expiration of the product 5 can be achieved by simply increasing the size of the fracture in the sheet 2, that is, by increasing the size of the outlet, performed by a simple further bending of the container 1.

In other words, in the container 1 described above, the fracture of the sheet 2 by the notch 8 always occurs gradually, i.e. in proportion to the degree of folding of the container 1, so that the expiration of the product 5 can be easily and intuitively controlled simply by bending the container 1 accordingly.

The number 7 in FIG. 11 designates a whole installation for the manufacture of sealed packaging containers 1 for a single dose, as described above and shown in FIGS. 1 and 2.

The packaging unit 7 consists of a frame 8, which stands on the floor on the support legs 9 and supports two unwinding devices 10 and 11. The unwinding device 10 holds the roll 12, from which the tape 13 of semi-rigid plastic is gradually unwound and fed to the forming section 16. The unwinding device 11 holds the roll 14, from which the tape 15 of flexible plastic is gradually unwound and fed to the forming section 16.

Between the unwinding device 10 and the forming section 16 there is a traction drive device 17, which is two drive rollers 18 for continuously feeding the tape 13 of semi-rigid plastic to the forming section 16. Similarly, between the unwinding device 11 and the forming section 16 there is a traction drive 19, which is two drive roller 20 for the continuous supply of flexible plastic tape 15 to the forming section 16.

An incision device 21 is located in front of the forming section 16, cutting across the semi-rigid plastic tape 13, forming a series of notches 6 on the semi-rigid plastic tape 13.

In a preferred embodiment, the tape 13 of semi-rigid plastic is fed continuously through the notch device 21. For this, two feed tension rollers 22 are arranged in front of the notch device 21, which are movable against the action of elastic means to temporarily stop the tape 13 in the notch device 21. In the preferred case the feed tension rollers 22 are attached to opposite ends of the articulated support arm 23, which rotates freely about a central axis of rotation 24; one end of the bracket 23 is connected to the pneumatic cylinder 25, which presses on the bracket 23 to keep the tape 13 in tension.

As shown in FIGS. 12 and 13, the notch device 21 has two parallel cutting inserts 26 that are movable to each other to grip the tape 13 of semi-rigid plastic and are provided with corresponding interchangeable cutting elements 27. In particular, the cutting elements 27 of each of the cutting inserts 26 are connected to the cutting insert 26 by a dovetail connection and at least one screw. It should be noted that depending on the shape of the incision 6, both cutting elements 27 may have sharp blades (not shown) or one cutting element 27 may have a sharp blade and the other cutting element 27 may have a supporting surface.

Preferably, the notch device 21 has a fixed frame 28 supporting four cylindrical guide elements 29 that extend through respective through holes 30 made in the cutting inserts 26, so that the cutting inserts 26 slide along the guide elements 29. The notching device 21 also comprises two linear an actuator 31 (typically pneumatic or hydraulic cylinders) that push the plates 26 toward each other.

As shown in FIGS. 11, 14, 15 and 16, in the forming section 16, the semi-rigid plastic tape 13 is superimposed on the flexible plastic tape 15, and the longitudinal sealing device 32 hermetically connects the two tapes 13, 15 to each other in the longitudinal direction (from the sides and in the center of the tape) with the formation of two adjacent tubes 33. The longitudinal sealing device 32 preferably comprises a cylindrical support roller 34 and three electrically heated cylindrical sealing rollers 35 located on a common axis 36. The sealing roller 35 can preferably move along a common axis 36 to enable quick adjustment of the axial position of the roller across the width of tapes 13 and 15 for sealing.

The metering device 37, located in the forming section 16 and located in front of the device 32 for longitudinal sealing of the package, delivers doses of the product to each tube 33 formed between the tape 13 of semi-rigid plastic and the tape 15 of flexible plastic. Behind the metering device 37 is a lateral sealing device 38, hermetically connecting the two tapes 13 and 15 with each other in the transverse direction, forming along each tube 33 a plurality of containers 4 (FIG. 1), each of which contains a dose of the product. The metering device 37 preferably comprises two product supply lines 39, each of which has a vertical end portion that extends between the longitudinal sealing device 32 and the lateral sealing device 38 and is located between the sealing rollers 35 of the device 32.

Behind the lateral sealing device 38 is another lateral sealing device 40, intended for additional lateral sealing of the tapes 13 and 15. In particular, the lateral sealing device 38 forms a narrow transverse seam for preliminary sealing of the tapes 13 and 15, and the next lateral sealing device 40 forms the next wide the seam of the final transverse sealing of the tapes 13 and 15. Sealing the tapes 13 and 15 in the transverse direction in two separate successive stages provides high quality ennuyu, extremely strong transverse seals and forms a hermetic container 1 containing no air inside. The latter circumstance is achieved due to the fact that the transverse sealing device 38 only performs the formation of a preliminary narrow transverse sealing seam of the tapes 13 and 15 and, thus, works extremely quickly, preventing air from entering each tube 33. In other words, the transverse sealing device 38 provides a simple and the fastest possible formation of preliminary transverse sealing of the tapes 13 and 15, not necessarily strong or of good quality, after which the device 40 immediately performs Xia further and final transverse sealing strips 13 and 15, without any special requirements for the speed of this operation.

In the preferred embodiment shown in the accompanying drawings, the sealing devices 32, 38, 40 are arranged vertically in a row and sequentially under each other.

In a preferred embodiment, the wide seam of the final transverse sealing has a width of 4-5 mm, and the narrow seam of the preliminary transverse sealing has a width of 1-3 mm. The wide seam of the final transverse sealing is preferably approximately twice as wide as the narrow seam of the preliminary transverse sealing. For example, the wide joint of the final transverse sealing is approximately 5 mm wide, and the narrow joint of the preliminary transverse sealing is approximately 2.5 mm wide. The actual size of the transverse and longitudinal sealing joints may obviously differ from those proposed above, depending on the characteristics of the tapes 13 and 15, the product and the sealed containers 1 being manufactured.

In a preferred embodiment, each transverse sealing device 38, 40 comprises a cylindrical support roller 41 and an electrically heated sealing roller 42, which has an equilateral triangle section and cooperates with the support roller 41. The vertices of each sealing roller 42 are beveled (smoothed) and form on the roller 42 three sealing surfaces 43 located at an angle of 120 ° relative to each other.

Behind the forming section 16, there is a cutter 44 that cuts each tube 33 transversely, sequentially separating the sealed containers 1. Preferably, the cutter 44 cuts each tube 33 by perforation, sequentially separating the sealed containers 1. If necessary, the cutter 44 also has a punch (not shown) for forming in each airtight container 1 through holes used to hang the airtight container.

The cutter 44 has a rigid frame 45, a fixed support plate 46 attached to the frame 45, a cutting plate 47 configured to move back and forth to and from the supporting plate 46 and supporting a series of knives, and a drive 48 for moving the cutting plate 47 back and forth forward towards and away from the support plate 46. The frame 45 holds four cylindrical guiding elements 49 protruding through respective through holes (not shown) in the cutting insert 47, allowing the insert 47 to slide along the guiding elements 49. The drive 48 preferably has a rotary motor 50 that moves the cutting insert 47 back and forth when traction aid 51.

Sealed containers 1 after separation from the tube 33 fall by gravity to the output conveyor belt 52, located under the cutter 44. Behind the cutter 44 is a cutting device 53, preferably designed to cut the remainder of the pipes 33, after the sealed containers 1 are separated; the cut pipe residues 33 are collected in a container (not shown) located under the device 53.

In a preferred embodiment, the tapes 13 and 15 are fed continuously through the sealing devices 32, 38, 40 (that is, through the forming section 16) and stepwise through the cutter 44. To implement this mode, between the forming section 16 and the cutter 44 there is a tension device 54 having two drive periodically working roller 55.

In a preferred embodiment, the tapes 13 and 15 are pre-printed and have control marks that are read by optical sensors to synchronize actions so that the areas printed on the tape are correctly centered on the finished containers 1. The control marks are preferably printed in the areas of the tapes 13, 15 cut by the cutter 44 , and thus are not available on finished containers.

Another embodiment includes a heating device 56 (shown schematically with a dashed line in FIG. 11) located in front of the forming section 16 and designed to heat and increase the flexibility of the flexible plastic tape 15. Heating the tape 15 in advance temporarily increases its flexibility so that a larger amount of product can be introduced into the cavity 4 and to obtain a very attractive filled airtight container 1.

To form the knurling shown in FIGS. 9 and 10, the outer surface of each roller 35 has circumferential grooves that are spaced at the same interval as the knurled ribs and mirror the shape of the knurled ribs; and the outer surface of at least the sealing roller 42 of the lateral sealing device 40 has circumferential grooves that are spaced at the same interval as the knurled ribs and mirror the shape of the knurled ribs. In one possible embodiment, the circumferential grooves have only the outer surface of the sealing roller 42 of the device 40, while the sealing roller 42 of the device 38 has no circumferential grooves. Alternatively, circumferential grooves are provided on the outer surfaces of the sealing rollers 42 of both lateral sealing devices 38 and 40.

The packaging unit 7 described above has two production lines located next to each other and working in parallel, but it can obviously have another number of such parallel lines (for example, one, three or four), depending on the required capacity.

The packaging unit 7 described above has several advantages: it is inexpensive and easy to manufacture and at the same time produces high-quality airtight containers 1 with extremely strong transverse sealing and containing a very small amount of air.

Claims (15)

1. A sealed breakable container (1) for a single dose, comprising: a first sheet (2) of semi-rigid plastic,
a second sheet (3) of flexible plastic, superimposed on the first sheet (2) of semi-rigid plastic and connected with it to form a sealed cavity (4) containing a dose of the product (5), and
an incision (6) formed in the first sheet (2) of semi-rigid plastic and designed to effect a controlled fracture of the first sheet (2) by an incision (6) and forming an outlet for the outlet of the product (5) through the first sheet (2), characterized in that the depth of the incision (6) varies along its length with the breaking of the first sheet (2) gradually along the incision (6). 2. An airtight breakable container (1) according to claim 1, wherein the notch (6) has a maximum depth in its central part. 3. An airtight breakable container (1) according to claim 2, wherein the notch (6) has a V-shaped cross section. 4. An airtight breakable container (1) according to claim 2, wherein the notch (6) has a W-shaped cross section. 5. An airtight breakable container (1) according to claim 2, wherein the notch (6) has a constant first depth in the peripheral sections and a constant second depth in the central part exceeding the first depth. 6. An airtight breakable container (1) according to claim 1, wherein in the place of the maximum notch depth (6), the first sheet (2) of semi-rigid plastic has a thickness in the range of 75-150 μm. 7. An airtight breakable container (1) according to claim 6, wherein in the place of the maximum notch depth (6), the first sheet (2) of semi-rigid plastic has a thickness of 100 μm. 8. An airtight breakable container (1) according to claim 1, wherein the difference between the maximum and minimum notch depth (6) is in the range of 50-150 μm. 9. An airtight breakable container (1) according to claim 8, in which the difference between the maximum and minimum notch depth (6) is 100 μm. 10. A sealed breakable container (1) according to any one of claims 1 to 9, in which the first sheet (2) of semi-rigid plastic is made of a layered material having a first outer supporting layer and a second inner thermally sealed layer,
between the supporting and thermally sealed layers there is an additional insulating or barrier layer,
the backing layer of the first sheet (2) of semi-rigid plastic is made of one of the following materials: polystyrene (PS), polyvinyl chloride (RVC), butadiene acrylonitrile styrene (ABS), amorphous polyethylene terephthalate (ARET), polypropylene (PP), and
the heat-sealing layer of the first sheet (2) of semi-rigid plastic is made of one of the following materials: polyethylene (PE) or polypropylene (PP). 11. A sealed breakable container (1) according to any one of claims 1 to 9, in which the second sheet (3) of flexible plastic is laminated and its layers may contain: polyethylene terephthalate (PET), polyethylene (PE), polyethylene with a barrier layer ( PE BARRIER), metallized polyethylene terephthalate (PETM), aluminum (ALU), oriented polypropylene (OPP), oriented polyamide (OPA). 12. An airtight breakable container (1) according to claim 1, wherein the portions of the first and second sheets (2, 3) surrounding the cavity (4) and hermetically connected to each other are knurled. 13. An airtight breakable container (1) according to claim 12, wherein the knurling is formed on the upper side of the second sheet (3) of flexible plastic. 14. An airtight breakable container (1) according to claim 12 or 13, wherein the knurling is made in the form of ribs running parallel to its short side. 15. An airtight breakable container (1) according to claim 14, wherein each rib has a height in the range of 0.10-0.30 mm, wherein the ribs are 1-2 mm apart, and each rib has a cross section in the form of a triangle, in which the angle at the apex is 45-75 °.

Images