EP0929467A1

EP0929467A1 - Packaging wrapper sealed with foils, and packaging method

Info

Publication number: EP0929467A1
Application number: EP96934592A
Authority: EP
Inventors: Eddy Daelmans; Raymond Vanoppre
Original assignee: Transpac NV
Current assignee: Amcor Flexibles Transpac BVBA
Priority date: 1995-12-29
Filing date: 1996-10-08
Publication date: 1999-07-21
Anticipated expiration: 2016-10-08
Also published as: EP0929467B2; JP2001515436A; DE69607044T2; PL182660B1; SK9898A3; DE69607044T3; WO1997024273A1; SK283172B6; ATE190287T1; CN1189137A; CN1071691C; GR3033520T3; EE03478B1; KR100417673B1; CA2227735A1; SI0929467T1; PL323588A1; HUP9900140A2; NO975926L; ZA9610893B

Abstract

A packaging wrapper consisting of a sheet sealable by means of at least one foil (22) and including an internal cold sealing coating arranged in two longitudinal strips (12, 14) on either side of the item to be packaged for retaining the foils. The sheet further comprises at least one additional transverse strip (24, 26) of cold sealing coating extending along one edge of the sheet (20) perpendicularly to the longitudinal strips (12, 14). The packaging method comprises closing the wrapper by means of the transverse strips (24, 26) in a direction parallel to the axis that passes through the foils (22).

Description

PACKAGING CLOSED ENVELOPE AND PACKAGING METHOD

The present invention relates to a packaging envelope for articles, said envelope being closed by means of at least one foil.

The invention also relates to the production of a package closed with foils.

In particular, the invention relates to the field of packaging of confectionery products. Generally, confectionery products are individually wrapped in a portion of pre-printed film of an appropriate size and shape, which individually wrapped products can in turn be packaged in bulk in a packaging bag of an appropriate size. Typically, the article to be wrapped is first completely wrapped in a portion of rectangular film and the envelope thus formed is closed by twists at two points located on either side of the article to be wrapped.

Note that these packages are not always closed with two twists. It is for example possible to deposit the article to be wrapped in the center of a suitable portion of film whose flaps projecting from the article are folded over said article before closing the envelope thus formed by stranding said flaps in a single foil . In the context of the present invention, the term "foil" is understood to mean the result of the stranded closure of said envelope.

An important problem that arises at this level is that of the retention of the foil. This retention can only be obtained at the price of a particular selection of the film used as a substrate, which must have appropriate mechanical characteristics such as pliability or, in particular, a pronounced tendency not to return to its initial position. after stranding said film.

In particular, this problem manifests itself in the packaging of articles of small sizes and of substantially round section such as confectionery products such as, for example, candies, lollipops, barley sugars, fruit pastes, chocolate bars or even larger products such as bottles, rolls of coins, ...

As a solution, it is known to select particular substrates known for their high pliability, such as waxed paper or cellophane or else synthetic films containing an appropriate amount of an additive increasing the pliability of said substrate.

This solution is obviously not satisfactory insofar as it considerably limits the possibilities of choice of films used as packaging substrate and insofar as it considerably increases the cost thereof.

There are known on the market packages closed by foils which are produced from substrates previously coated with a heat seal coating. When papillotes are formed at the ends of the envelope containing the article to be packaged, a heat source is approached for a certain period of time at a temperature between approximately 120 and 160 ° C., generally these are the jaws performing stranding which are heated, but it is also possible to blow hot air by means of a tube of appropriate size - on said foils, which results in the melting of the heat sealing plaster and the sealing foil thus formed during the cooling of said heat seal coating.

This solution makes it possible to increase the choice of the packaging substrate, but is however not yet entirely satisfactory insofar as it does not allow the selection of a substrate having a low resistance to high temperatures and, more serious, it is completely unsuitable for the packaging of heat-sensitive articles, in particular chocolate products. Another defect of this solution is the relatively low speed which it imposes, it is, in fact, necessary to keep in contact the papillotes and the heating element for a time sufficient to obtain the melting of the sealing coating.

It is generally considered that the packaging of 800 articles per minute is the highest rate that can be obtained with a packaging unit operating on the closing principle of the envelope by stranding and heat sealing of the foil thus formed.

To avoid the drawbacks of heat sealing and without being limited in the choice of films used, document GB-A-1096058 proposes a film with a cold sealing coating which, after closing the envelope by stranding the foil, has excellent retention. This cold sealing coating is in the form of two longitudinal strips located in the areas of formation of the papillotes on either side of the article to be packaged. By cold sealing is meant a sealing which is carried out instantaneously by simple contact at a temperature of between 0 and 50 ° C. approximately. In reality, the temperature is not a critical parameter with regard to obtaining a seal by means of a cold sealing coating and has practically no influence on the quality of the seal obtained. Sealing is therefore carried out without the need for additional heat at ambient temperature of the space in which the packaging unit is located.

In fact, cold sealing coatings have, until now, been mainly used as a layer on a substrate which undergoes little or no deformation. Significant blocking problems can be expected due to the self-adhesive properties of the cold sealing coating in any use of this cold sealing coating on a non-planar substrate.

The method described in the aforementioned document takes advantage of this characteristic to obtain the retention of the foil.

In addition, in the case of a papillote retained by means of a cold sealing plaster, it is not necessary to apply pressure over the entire length of the papillote. This nevertheless results in a uniform sealing over the entire length of the foil thanks to the action of the torsional forces imparted during the stranding of the envelope.

This method therefore allows the use of cheaper films and having better properties (rigidity, propensity to print, aesthetic qualities) for packaging articles without restrictions as to the shape or the heat sensitivity of said articles. As for the rates which it is possible to achieve with a packaging unit operating according to the principle of closing the packaging by stranding and cold sealing of the foil thus formed, it should be noted that the only limit as to the cadence is imposed by the machine itself. This packaging method therefore makes it possible to reach rates of at least 1,500 articles per minute.

The object of the present invention is to provide a new packaging of the cold sealing type for the foil which has all the known advantages of this type of packaging but which, moreover, allows an almost hermetic closure of the packaging. Another object of the invention is to provide a new packaging method specially suitable for this type of packaging.

According to the invention, this object is achieved by a packaging envelope made of a film and intended to be closed by at least one foil comprising, on the inner side with respect to the article to be packaged, a sealing coating to cold arranged in two parallel longitudinal strips on either side of the article to be packaged, characterized in that the film has at least one additional transverse strip of cold sealing plaster arranged along an edge of the film perpendicular to the said longitudinal strips of sealing plaster so as to allow, after the stranding of the envelope, to close it in a direction parallel to the axis passing through the two twists.

Thus, the packaging is closed almost hermetically, which is very advantageous with regard to the preservation of the articles since it prevents the penetration of moisture, gas, air or other substances and, at the same time, preserves the aromas. the interior.

According to an advantageous embodiment, the film has two transverse bands of cold sealing plaster extending perpendicularly between the longitudinal bands along the opposite edges. In this way, when the article is placed on the film for packaging, it is completely surrounded by cold sealing strips.

The invention also provides a new method of packaging an article in a film comprising two longitudinal strips of cold sealing plaster and at least one transverse strip. cold sealing plaster extending along an edge perpendicularly between the longitudinal strips according to which the article is deposited on the film on the side of said strips, the two sides which are perpendicular to the longitudinal strips are raised substantially vertically, the two sides are brought together above the article and their edge is sealed, by pressure, one to the other, the two edges thus sealed are folded over the article and the projections of the film protruding from the part are twisted and on the other the article to form two twists at the longitudinal strips. This method, which allows the application of pressure, allows a perfect closure over the entire length of the film between the twists. Since the sealing plaster also allows good closure at the papillotes, the packaging will be perfectly sealed on all sides. When the film has two longitudinal strips and two transverse strips, it is also possible to produce a sealed package with a single foil. Simply place the article in the middle of the four strips, lift the four sides of the film and twist them above the article to form the foil. When preparing a roll of packaging film, one side of which is coated with sealing plaster, an anti-adhesive coating of the film used is preferably applied, at least partially, to the other side in order to avoid adhesion. by contact between the side coated with sealing plaster and the other side during winding. It should however be noted that there are so-called "dry" cold sealing coatings which, when used in conjunction with certain substrates such as polypropylene films, do not require such a non-stick coating. These two methods can also be used in the context of the present invention. All the non-stick coatings which are conventionally applied to the back of the face of the film which carries the strips of cold sealing coating can be used within the framework of the present invention. In particular, suitable non-stick coatings consist of mixtures of polyamide resins and polyethylene waxes (for example the products 10-609345-3p from the company SIEGWERK and 994404-x from SICPA). In general, these non-stick coatings are deposited on the substrate at a rate of 1 to 5 g / m ² .

According to a particularly advantageous embodiment, the portion of film coated with cold sealing coating intended for the formation of the packaging envelope has areas coated with cold sealing coating 1 to 50 mm wide located around the space reserved for the item to be packaged. In doing so, any contamination problem between the packaged article and the cold sealing coating is avoided, if necessary, and a substantial saving is made on said sealing coating. On the other hand, the retaining property of the papillotes is fully retained since the zones coated with cold sealing coating have, in an appropriate manner, been placed at the location of the film where said papillotes are formed. The cold sealing plaster is therefore preferably placed in an appropriate pattern adapted to the article to be packaged.

Said areas coated with cold sealing coating may be in the form of parallel strips (for example for a candy or a lollipop whose packaging has two twists) or in the form of discontinuous areas (triangles, quadrilaterals) depending on the shape the article to be packaged or the presentation of said article (for example lollipop or barley sugar, the packaging of which has only one foil).

As indicated above, one of the advantages of the cold sealing coating is that it allows the use of a wide range of possibilities as regards the nature of the substrate used. Examples of suitable substrates are plastic films of about 10 to 100 microns made of extruded and oriented polypropylene, polypropylene as a cast film, polyester, polyethylene, extruded and oriented polyamide or polyamide as a cast film.

In accordance with the present invention, it is also possible to use a paper substrate (rubbed or coated). Generally, any support material or flexible packaging material may be suitable as a substrate for the present invention. These different substrates may consist of a single layer, a single metallized layer or in several laminated and / or coextruded layers.

The choice of cold sealing coating is not critical. As a cold sealing coating, pressure sensitive adhesives can be considered which are substances which are permanently sticky and which spontaneously adhere to the surface of most materials under the effect of simple moderate pressure.

As a general rule, pressure-sensitive adhesives are compositions based on natural and / or synthetic rubbers combined with modified cellophanes, phenol-formaldehyde resins or hydrocarbon resins (waxes). Besides rubbers, polymers based on styrene, (meth) acrylic acid or vinyl ether are widely used, alone or as a mixture, also in combination with resins. Finally, it is also possible to use silicone resins. Preferably, compositions comprising mixtures of natural and synthetic rubbers and copolymers of (meth) acrylic acid and styrene are used. In accordance with the present invention, the cold sealing coatings are deposited on the substrate at a rate of approximately 1 to 5 g / m ² .

Cold seal coatings can be applied as a solution, dispersion or even in the molten state.

It is also possible to deposit between and / or on either side of the strips of cold sealing plaster another plaster, for example inert or non-stick. As other coating, any coating compatible with the nature of the product to be packaged can be used. In general, these other coatings are also deposited on the substrate at a rate of approximately 1 to 5 g / m ² . The films in accordance with the present invention are prepared according to coating deposition techniques well known to those skilled in the art such as, for example, heliographic or flexographic printing or even offset printing.

The invention will be better understood on reading the description of some embodiments presented below, by way of illustration, with reference to the appended drawings in which: - Figure 1 shows a known packaging of the kind described in document GB-A-1096058;

- Figures 2a, 2b and 2c show in cross section the successive phases of the packaging of the article using a film according to Figure 1;

- Figures 3a, 3b and 3c are perspective views of the packaging phases shown in Figures 2;

- Figure 4 is a view of the article packed with two papil¬ lotes; - Figure 5 is a plan view of a packaging film according to the present invention;

- Figure 6 shows a perspective view of a roll of packaging film;

- Figures 7a, 7b, 7c and 7d are the successive sequences of packaging the article using a film according to the present invention;

- Figures 8a, 8b and 8c show perspective views of the different packaging sequences of the article with the film according to the present invention;

- Figure 9 shows the wrapped article after the formation of the two foils and

- Figures 10 and 1 1 show the sealing and folding of the package according to the present invention in the direction parallel to the axis passing through the foils.

Figure 1 shows a strip of film generally indicated by the reference 10 which is coated with two longitudinal strips 12, 14 with a cold sealing coating. The articles to be packaged are shown in dotted lines by the reference 16. The film strip is intended to be cut along the lines 18 in order to provide film pieces 20 identical to each other which act as the packaging envelope for the articles. 16. In FIG. 1, the silhouette of twists 22 also obtained by dotted lines has been obtained by stranding projections on either side of the article to be packaged 16.

Figures 2 and 3 show the different sequences of a conventional packaging process, Figures 2 being sections along a plane perpendicular to the axis passing through the future foils. The article to be packaged 16 is placed on a film 20 and the two sides with the cutting edges 18 of FIG. 1 are raised vertically against the article 16. Note that, in the example shown, article 16 is off-center on the film 20 so that one of the panels, in this case that indicated by A, is longer than the panel B, as shown in FIG. 2a. The shortest section B is then folded down on the article 16 (see Figures 2b and 3b) and then the A section on the article 16 and the edge of the section B (see Figure 2c) to form the structure of the Figure 3c. The two ends projecting beyond the article 16 are then twisted, each turning in the direction of the folding of the pan A to form the two twists 22 shown in FIG. 4.

Figure 5 shows a packaging film 30 according to the present invention. In this Figure, the same reference numbers have been used to designate the parts corresponding to that of Figure 1. As can be seen, this film 30 also comprises two longitudinal strips 12 and 14 of cold sealing plaster. According to the invention, the film also comprises transverse bands 24 and 26 extending along the cutting edges perpendicularly between the longitudinal bands 12 and 14 on either side of the spaces reserved for the articles to be packaged 16 .

In use, the film 30 is delivered from a roll as shown in Figure 6, the cold sealing plaster structure 34 being on the inside. The film 30 is then sectioned along the cutting lines 18 passing through the middle of the transverse strips to form individual films 20.

The film 30 is particularly suitable for an advantageous packaging method proposed by the present invention and explained in more detail below with reference to Figures 7 to 11. The article 16 is placed on a film 20 inside the frame of cold sealing plaster and the two side panels are folded up, as shown in Figures 7a and 8a. However, unlike the known method, article 16 is this time placed in the center of the film so that the two sides A and B are perfectly the same length. Then fold the two sides simultaneously on the article 16 so that their inner edges with the strips 24 and 26 are placed against each other, as shown in Figure 7b. Next, as shown in FIG. 10, pressure is exerted on the outside of each of the edges of the panels A and B over the entire width in order to properly seal these two panels together at the level of their cold sealing coating. This operation of folding the sides A and B and of sealing their edges can be carried out in a single operation between the jaws of a press 28 (Figure 7b). A sealing rib 32 is thus obtained which extends over the entire width, as shown in FIGS. 7c and 8b. This rib is then folded and folded over the packaging according to Figures 7d and 8c, preferably, exerting vertical pressure according to Figure 1 1 to give the packaging an attractive presentation. The packaging is finished by twisting the two ends in the direction of the folding of the rib 32 to form two twists. Thanks to the presence of the transverse strips 24, 26 of cold sealing plaster and thanks to the use of pressure, a perfect closure is obtained over the entire width of the packaging. The longitudinal strips 12 and 14 also provide lateral sealing during the formation of the twists. This produces an almost airtight packaging which prevents the release of aromas or the penetration of air, humidity, harmful odors, etc.

The examples which follow illustrate the invention further without limiting it.

Example 1: a non-stick coating (10-609345-3p from SIEGWERK) is deposited on a white oriented polypropylene film 30 microns thick at a rate of 1.5 g / m ² . Longitudinal strips of 15 mm width of cold sealing plaster (product 22-392 from the company CRODA) are deposited on the other side of the same film at a rate of 3 g / m ² spaced 40 mm apart and perpendicular to the longitudinal strips, between these strips, parallel strips of 15 mm width of cold sealing plaster (product 22-392 from the company CRODA) at a rate of 3 g / m ² , spaced 80 mm apart, with a length of 40 mm.

Example 2: use of the film for making packages closed with foils. With the films of Example 1, chocolate products (of various sizes, weights and shapes) are packaged with a wrapping-stranding machine from the company PACTEC. The machine is set to a rate of 1,200 products per minute.

We thus obtain articles wrapped in an envelope closed by foils with an impeccable presentation and excellent retention of the foil. The packages formed with the film of Example 1 have the particularity of being completely hermetic and waterproof.

Claims

1. Packaging envelope consisting of a film (20) intended to be closed by at least one foil (22), comprising, on the inner side relative to the article to be packaged (16), a cold sealing coating arranged in two parallel longitudinal strips (12, 14) on either side of the article to be packaged (16), characterized in that the film (20) has at least one additional transverse strip (24), (26) cold sealing plaster disposed along an edge of the film (20) perpendicular to said longitudinal strips (12, 14) of sealing plaster so as to allow, after stranding the envelope, to close it ci in a direction parallel to the axis passing through the twists (22).

2. Packaging according to claim 1, characterized in that the film (20) has two transverse strips (12, 24) of cold sealing plaster extending perpendicularly between the longitudinal strips (12, 14) along the edges opposites.

3. Packaging envelope according to any one of claims 1 or 2, characterized in that the face of the film (20) opposite to that carrying the strips of cold sealing plaster is coated with a non-stick coating .

4. Method for packaging an article (16) in a film (20) comprising two longitudinal strips (12, 14) of cold sealing plaster and at least one transverse strip (24, 26) of plaster cold sealing extending along an edge perpendicularly between the longitudinal strips (12, 14) according to which the article is deposited on the film (20) on the side of said strips, the two sides which are perpendicular are raised substantially vertically to the longitudinal strips, the two sides are brought together above the article (16) and the edges are sealed to one another by pressure, the two edges thus sealed are folded over the article and the projections are twisted of the film protruding on either side of the article to form two twists at the level of the longitudinal strips (12, 14).

5. Method according to claim 4, characterized in that the folding and sealing operation of the edges of the panels above the article is made in a single operation between the jaws of a press.