HK1023325B - Wrapper closed by twist wraps and wrapping method - Google Patents

Description

Package sealed by twist and packaging method

The invention relates to a package made of a film and sealed by two kinks at the two ends of the package to be packaged, and to a method for packaging articles using such a package.

The invention relates in particular to the field of candy packaging.

The candy is typically individually wrapped in a suitably shaped and sized pre-printed film, and these individually packaged products can be packaged by weight in appropriately sized packages. Typically, the package to be packaged is first completely enclosed within a rectangular piece of film and the package so formed is closed by a kink at two points at the ends of the package to be packaged.

Within the scope of the invention, kinking refers to the result of twist sealing of the package.

An important problem in this respect is the setting of the kink. This setting can only be obtained with a particular choice of film as substrate, which must have suitable mechanical properties, such as foldability, or, in particular, no significant tendency to return to its original position after twisting the film.

This problem occurs in particular when packaging small and substantially round-section items, such as confectionery products, for example candies, lollipops, maltose, jams, chocolate bars or also bulky products such as bottles, rolls and the like.

As a solution, one chooses either a known special substrate with high foldability, such as waxed paper or cellophane, or a synthetic film containing suitable additives to improve the foldability of the substrate.

This approach greatly limits the options for films as packaging substrates and greatly increases the cost.

The packaging which is found on the market by means of a kink seal is realized with a substrate which has previously been coated with a heat-seal coating. When a kink is formed at the end of the package containing the material to be packaged, a heat source having a temperature of between about 120 ℃ and 160 ℃ is approached for a period of time. Typically, the heated is a twisting fixture, but it is also possible to blow hot air over the kink using a suitably sized tube, with the result that the heat seal coating melts and seals the kink so formed when the heat seal coating cools.

Document GB-a-1096058 proposes a film with a cold seal coating which has excellent setting properties after twist-and-twist sealing of the package. The cold seal coating is in the form of two longitudinal strips located in the area where the two sides of the package to be packed are twisted.

Cold sealing means that sealing is accomplished instantaneously by simple contact in the temperature range of about 0 c and 50 c. In fact, temperature is not a critical parameter for sealing with cold seal coatings and has little effect on the quality of the seal obtained. Therefore, the sealing is performed at the ambient temperature of the space in which the packaging unit is located, and it is not necessary to provide an auxiliary heat source.

Therefore, the method can package an article using a film which is inexpensive and excellent in properties (hardness, feeling, appearance) without being limited by the shape of the article or the sensitivity to heat.

The object of the present invention is to provide a new packaging form with a kink seal which is superior to the currently known packaging and a new packaging method.

To achieve this object, the invention provides a packaging made of film, which is sealed by two kinks on both sides of the packaging to be packaged, characterized in that the film on the inner side of the packaging to be packaged has a sealing coating which is distributed along two transverse strips on both sides of the packaging to be packaged and is parallel to the axis through which the two kinks pass.

The seal coating may be a cold seal coating or a heat seal coating.

The film may additionally comprise two longitudinal strips of seal coating extending along both sides of the article to be packaged, perpendicular to the transverse strips in the kink formation zone. These seal coatings may also be cold seal coatings or heat seal coatings. Cold seal coatings are preferred when the film substrate has low resistance to high temperatures and/or when the package to be packaged is sensitive to heat, particularly chocolate products.

The heat seal coating may be a layer of Polyethylene (PE) extruded on oriented polypropylene (OPP).

As cold seal coating, pressure-sensitive adhesives are conceivable, which are substances that can adhere permanently and under simple light pressure immediately to most materials.

Pressure-sensitive adhesives are generally based on natural and/or synthetic rubbers, with modified cellophane, phenol-formaldehyde resins or hydrocarbon-containing resins (waxes). In addition to rubbers, polymers based on styrene, methacrylic acid or vinyl ethers are widely used, alone or in mixtures, also in mixtures with resins. Finally, silicone resins may also be used. It is preferred to use a composition comprising a blend of natural and synthetic rubbers and a copolymer of methacrylic acid and styrene.

These cold seal coatings are applied to the substrate in a proportion of about 1 to 5 grams per square meter. They may be applied in solution, dispersion or even molten form. Coating application techniques known to those skilled in the art can be used, for example, photomechanical or flexographic printing or also offset printing.

The invention also proposes a method for packaging an article in a film comprising at least two transverse sealing coating strips, according to which the article is placed on the edges of said coating strips of the film and, between the two coating strips, the two faces with said coating strips are folded up almost perpendicularly, the two faces are brought closer together on the article and their edges are sealed to each other, the two edges thus sealed together are flattened onto the article, and the film beyond the two ends of the article is then twisted to form two kinks.

When the coated strip includes a cold seal coating, the folding and sealing of the edge of the coated strip over the article is preferably accomplished in one pass in the jaws of the extruder.

When the coating is a heat-seal coating, the edges are sealed to each other by heat sealing.

The advantage of the invention is that the twist-top package is sealed for the first time in a transverse direction between two kinks. Since the sealing at the kink is good even without longitudinal coating in the area where the kink is formed, a completely closed package is achieved.

For packages with a hot or cold seal coating in the longitudinal region, i.e. a sealed closure at the kink, an almost gas-tight closure is achieved due to the transverse closure. Such a fully enclosed package is highly advantageous for the preservation of goods because it prevents the ingress of moisture, gases, air or other harmful substances while retaining the aroma within the package.

The invention will be better understood from reading the following description of several embodiments, with reference to the accompanying drawings, in which:

FIG. 1 is a schematic plan view of a first embodiment of the package according to the invention;

FIG. 2 is a schematic plan view of a second embodiment of the package according to the invention;

figures 3a, 3b, 3c and 3d show successive stages of packaging an article according to the packaging of the invention;

FIGS. 4a, 4b, 4c and 4d show perspective views of different packaging stages;

figures 5 and 6 show the folding and sealing of the package according to the invention in a transverse direction parallel to the kink passing axis.

Figure 1 shows a strip of film, indicated as a whole by 10, which is a well-defined film, just twisted enough to obtain a strong kink which does not open, i.e. a substrate which does not require glue to hold the kink. Such films may be, for example, cellophane, cast polypropylene film, waxed paper, aluminum/OPP bonded paper, and the like.

The object to be packaged, shown by a broken line, is indicated with 12. The strip film 10 is cut along line 14 to provide mutually equal foils 16 as a wrapper for the articles 12. The outline of the kink 18 obtained by twisting the projecting portions of the two ends of the item to be packaged 12 is also shown in figure 1 by a broken line.

According to the invention, the strip-shaped film 10 is provided with a sealing coating 20 extending transversely of the strip-shaped film on the inside with respect to the items 12 to be packaged. These strips 20 ride on the cut lines 14 so that after the strip film 10 is cut, each foil 16 has two transverse strips 20a, 20b of seal coating on either side.

In the example shown in fig. 1, the seal coat is a cold seal coat, such as products 22-392 of the CRODA company, applied at a rate of 3 grams per square meter.

Fig. 2 shows a second embodiment of a packaging film 40 according to the invention. The film 40 is formed of extruded oriented polypropylene and the film itself does not have the setting characteristics of the kink 18. However, in order to be able to form these kinks 18, two longitudinal strips 42, 44 of cold glue coating, which can consist of the same material as the transverse sealing strips 20 in the embodiment of fig. 1, are applied to the film on the inside of the item to be packaged 12 in the two regions in which the kinks 18 are formed. The embodiment of fig. 2 includes transverse heat seal coating stripes 46, which are formed at the edges of each film 46a and 46b after the film is cut. These transverse heat seal coating strips may be formed of PE layers extruded onto the OPP.

Different combinations are possible between the embodiments according to fig. 1 and 2. Thus, for example, the transverse cold seal coating strip of FIG. 1 can be exchanged for a transverse heat seal coating strip. Likewise, the hot seal 46 of FIG. 2 may be replaced with a cold seal. In addition, the longitudinal strips 42, 44 of FIG. 2, as well as the transverse strips 46, can be formed of a heat seal coating or a cold seal coating.

Figures 3a to 3d and 4a to 4d show different successive stages of the packaging method of the invention, using packages such as those described above with reference to figure 1 or figure 2. The article 12 is disposed within the transverse strips 20a and 20b of one of the foils 16. In the figure, the foil 16 of fig. 1 is shown as an example, but of course the method can also be used for the film of fig. 2 and in various possible combinations. The two sides a and B with the transverse seal-coating strips 20a and 20B are then folded upwards, as shown in fig. 3a and 4 a. The two sides a and B are then folded simultaneously inwardly over the article 12 so that their inner edges with the transverse strips 20a and 20B are opposite each other as shown in figure 4B. Then, as shown in fig. 5, pressure is applied over the entire width of the outside of each of the two sides a and B to seal the cold seal coatings of the two sides together well. This process of folding up the sides a and B and sealing the edges thereof may be performed in one step in the clamp 48 (fig. 3B) of the extruder. In this way, a sealing rib 50 extending over the entire width is obtained, as shown in fig. 3c and 4 b. The ribs are then folded and flattened onto the package as shown in fig. 3d and 4c, preferably with vertical pressure applied as shown in fig. 6, making the appearance of the package more attractive. The two ends are twisted in the direction of flattening of the rib 50 to form the two kinks 18 of figure 4d and the packaging is complete.

Thanks to the transverse cold seal coating strips 20a and 20b and to the use of pressure, perfect closure is obtained over the entire width of the package. Furthermore, kinks 18, in particular knots twisted according to fig. 2 at the longitudinal sealing coating strips 42 and 44, are used for the side sealing. In this way, an almost airtight package is achieved, which prevents escape of aroma or entry of air, moisture, noxious odors, etc.

In the case of transverse heat sealing of the coated strip, the extruder clamp 48 may be heated to around 150 ℃ to obtain a good seal between the sealing strips 20a and 20 b. It is also possible to blow hot air (150-.

Claims (7)

1. A package, consisting of a film (10, 40) divisible into individual foils (16) and closed by two kinks (18) on both sides of a package (12) to be packaged, characterized in that the film (10, 40) on the inside with respect to the package (12) to be packaged has a closing coating, which is distributed along the two transverse strips (20a, 20b) and (46a, 46b) on both sides of the package (12) to be packaged and parallel to the axis through which the two kinks (18) pass.

2. A package as in claim 1, wherein the coating is a cold seal coating.

3. A package as in claim 1, wherein the coating is a heat seal coating.

4. A package as claimed in claim 2 or 3, wherein the film further comprises two longitudinal strips (42, 44) of cold seal coating extending on either side of the package (12) to be packaged, perpendicular to said transverse strips (46a, 46b) in the kink formation zone.

5. A package as claimed in claim 2 or 3, characterized in that the film additionally comprises two longitudinal strips of heat-seal coating, extending on both sides of the package (12) to be wrapped, perpendicular to said transverse strips in the kink formation zones.

6. Method for packaging an article (12) in a foil (16) of film (10, 40), the foil comprising at least two transverse sealing coating strips (20a, 20b) (46a, 46b), according to which method the article (12) is placed on the edges of said coating strips of the foil (16) and between the two coating strips, the two faces carrying said coating strips are folded almost perpendicularly, the two faces are brought closer together on top of the article (12) and the edges are sealed to each other, the two edges thus sealed are flattened onto the article (12), and the film beyond the two ends of the article is then twisted to form two kinks (18).

7. Method according to claim 6, characterized in that the folding and sealing of the edges of the two faces on the top of the article is carried out in one operation in the jaws of an extruder.