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Title:
COMPOSITE FILM FOR A TUBE WITH A 360° PRINTING EFFECT
Document Type and Number:
WIPO Patent Application WO/2020/229210
Kind Code:
A1
Abstract:
The invention concerns a composite film for receptacles, in particular for tubes, with a plurality of layers connected to one another in a sheetlike manner to form a layer stack, this composite film comprising : - a base film (1) having a lower surface (8) and an upper surface (10); - a cover film (2) having a lower surface (11) facing the base film (1) and an upper surface (12); - an ink layer (7) applied on the upper surface (12) of the cover film (2), excepted on a first lateral edge margin M1 of the composite film. The composite film comprises an ink line (13) applied between the base film (1) and the cover film (2), in said first lateral edge margin M1 region, along the whole length of the composite film.

Inventors:
SURVANA SUDHEER (GB)
Application Number:
PCT/EP2020/062261
Publication Date:
November 19, 2020
Filing Date:
May 04, 2020
Export Citation:
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Assignee:
ALBEA SERVICES (FR)
International Classes:
B32B1/08; B32B15/085; B32B27/08; B32B27/32; B29D23/20
Domestic Patent References:
WO2015181350A12015-12-03
WO2015061980A12015-05-07
WO2013051011A22013-04-11
Foreign References:
US20100243094A12010-09-30
CN204387517U2015-06-10
US20180147791A12018-05-31
Attorney, Agent or Firm:
GEVERS & ORES (GROUPEMENT 92) (FR)
Download PDF:
Claims:
CLAIMS

1. A composite film for receptacles, in particular for tubes, with a plurality of layers connected to one another in a sheetlike manner to form a layer stack, this composite film comprising:

- a base film (1) having a lower surface (8) and an upper surface (10);

- a cover film (2) having a lower surface (11) facing the base film (1) and an upper surface (12);

- an ink layer (7) applied on the upper surface (12) of the cover film (2), excepted on a first lateral edge margin (M1) of the composite film;

wherein the composite film comprises an ink line (13) applied between the base film (1) and the cover film (2), in said first lateral edge margin (M1) region, along the whole length of the composite film.

2. A composite film according to the preceding claim, wherein the ink line (13) has a lateral start that starts at least where the ink layer (7) finishes.

3. A composite film according to any of the preceding claims, wherein the ink line (13) has a lateral finish that finishes before a first lateral edge (9) of the composite film.

4. A composite film according to any of the preceding claims, wherein the ink line (13) is applied on the lower surface (11) of the cover film (2).

5. A composite film according to claims 1 to 3, wherein the ink line (13) is applied on the upper surface (10) of the base film (1).

6. A composite film according to any of the preceding claims, wherein the base film (1) and the cover film (2) each comprises a material which is sealable to itself and/or to the material of the other of these two films (1, 2).

7. A composite film according to any of the preceding claims, wherein the material forming the lower surface 8 of the base film (1) is sealable to the material forming the upper surface (12) of the cover film (2).

8. A composite film according to any of the preceding claims, wherein the material forming the lower surface (8) of the base film (1) consists preferably of polyethylene.

9. A composite film according to any of the preceding claims, wherein the material forming the upper surface (12) of the cover film (2) consists preferably of polyethylene.

10. A composite film according to any of the preceding claims, wherein the base film (1) is a multilayered film.

11. A composite film according to any of the preceding claims, wherein the thickness of the base film (1) is comprised between 200 and 400pm, and the thickness of the cover film (2) is comprised between 15 and 120pm.

12. A receptacle, in particular a tube, with a wall consisting of a cut-to- size film piece of a composite film as claimed in claim 1, said film piece comprising a first lateral edge margin (M1) and a second lateral edge margin (M2), wherein the two lateral edges margins (M1, M2) are joined together by overlapping, the cover film upper surface (12) of the first lateral edge margin (M1) being sealed to the base film lower surface (8) of the second lateral edge margin (M2).

13. A receptacle according to claim (12), wherein it comprises a gap (G) between a lateral finish (16) of the ink layer (7) and a second lateral edge (17) of the composite film, said ink line (13) extending at least over the whole gap (G).

14. A method for producing a composite film as claimed in claim 1, wherein it comprises the following steps:

- printing the ink line (13) on the upper surface (10) of the base film (1);

- laminating the base film (1) with the cover film (2);

- applying the ink layer (7) on the upper surface (12) of the cover film (2);

the last two steps could be reversed.

15. A method for producing a composite film as claimed in claim 1, wherein it comprises the following steps:

- printing the ink line (13) on the lower surface (11) of the cover film (2);

- applying the ink layer (7) on the upper surface (12) of the cover film (2);

- laminating the base film (1) with the cover film (2);

the last two steps could be reversed.

Description:
DESCRIPTION

TITLE : Composite fil m for a tube with a 360° pri nti ng effect

Technical field

The invention relates to a composite film for a receptacle, in particular a composite film for a tube, with a 360° printing effect.

The composite film comprises a plu rality of layers which are connected to one another in a sheetlike man ner to form a layer stack. Th is layer stack is provided with at least two sealable layers having each a material which is sealable to the other.

The invention also concerns the tube that is formed by join ing the two end portions of the composite film to each other, by overlapping and by welding them thanks to the two sealable layers.

Conventional composite films for tubes or the like are mostly between 200 and 700 pm thick, in order to ensure a rig idity of the tube which is sufficient for use.

The outer surface of the composite film , form ing the outer surface of the tube, is provided with a printed layer. The invention ensures an uninterrupted printing pattern all around the tube, without any u nprinted gap nearby the overlapping .

The invention finally concerns methods for producing such composite film .

Technical backg round

The plastic packages currently used on the market are main ly divided into two categories : extruded tubes and laminated tubes.

These two types of tubes differ in the printing process.

The extruded tube is printed on the curved surface after the tube is formed, so it is very easy to ach ieve the 360° printing effect on the whole tube.

The lam inated tube is pre-printed : the composite film composing the tube is printed on its whole outer surface, then wound, and its two end portions are overlapped and sealed by any known technique. For a conventionally lam inated composite tube, the tube body has a bad side seam due to hot sealing on the ink and the composite film (mainly composed of polyethylene material) . Th is bad side seam is due to the incompatibility between ink and polyethylene.

For avoiding th is bad side seam , it is known to leave a blank area (i.e. an u nprinted area) on a lateral edge marg in of the outer surface of the composite film . So that the first end portion of polyethylene can easily be sealed on the lateral edge margin of polyethylene. In th is case, the lap weld is clean , but a little unprinted gap appears at the periphery of the side seam . Th is unprinted gap makes the tube having certain defects in appearance.

For avoiding this unprinted gap, it is known to use the reverse printing . This technique consists in printing the whole outer surface of a base film of the composite film , and then laminating a transparent cover film on the base film , so as to protect the imprint. The cover film is in polyethylene. So that both end portions are in polyethylene and can easily be sealed, for forming a clean side seam . Flowever, due to the occlusion of the cover film , the appearance of the imprint is too dark. Moreover, there is a risk of ink contamination as the imprint, located in an inner layer of the side seam , is exposed to the product stored inside the tube.

Invention content

In order to solve the problems existing in the prior art, the present invention provides a composite film for the production of composite receptacles, particu larly tubes, having a 360° printing effect that satisfies high requirements in terms of decoration effect, without any risk of ink contamination , and fu rthermore, that can be processed with current printing technology.

The composite film of the invention is conventionally formed by a plurality of layers connected to one another in a sheetlike manner to form a layer stack. This composite film comprises :

- a base film having a lower surface and an upper surface;

- a cover film having a lower surface facing the base film and an upper surface;

- an ink layer applied on the upper surface of the cover film , excepted on a first lateral edge margin of the composite film ; - an ink line applied between the base film and the cover film , in said first lateral edge marg in reg ion , along the whole length of the composite film .

The main idea of the invention is to add an ink line that enables to extend the ink layer in the reg ion of the conventional unprinted gap nearby the side seam .

In other words, the idea is to combine the technique of the blank area for having a clean side seam , and the techn ique of the reverse printing for decorating the remain ing gap.

The color of the ink line m ust correspond to the backg round color of the ink layer, so that the user will not notice this colored gap.

At the end, when the composite film is rolled for forming the tube, there will be a 360° printing effect, thanks to the ink layer completed by the ink line.

According to the invention , the ink line has a lateral start that starts at least where the ink layer finishes : as a resu lt, there is no space between the ink layer and the ink line. I n other words, the ink line is located in the continu ity of the ink layer, but in a lower level in the composite film . Consequently, from outside, the user won’t notice the end of the ink layer.

The ink line is located in an inner layer of the composite film . Due to the overlapping , a first lateral edge of th is inner layer is in contact with the product. According to the invention , the ink line has a lateral fin ish that finishes before a first lateral edge of the composite film . Th is is important for avoiding ink contamination with the product stored inside the tube.

According to different embodiments, that can be taken together or separately:

the ink line is applied on the lower surface of the cover film .

- the ink line is applied on the upper surface of the base film .

the base film and the cover film each comprises a material which is sealable to itself and/or to the material of the other of these two films.

- the material form ing the lower surface of the base film is sealable to the material forming the upper surface of the cover film . the material form ing the lower surface of the base film consists preferably of polyethylene

- the material forming the upper surface of the cover film consists preferably of polyethylene

the base film is a multilayered film

the cover film is a mu ltilayered film .

the thickness of the base film is comprised between 200 and 400pm , and the thickness of the cover film is comprised between 1 5 and 1 20pm .

The invention also relates to a receptacle, in particu lar a tube, with a wall consisting of a cut-to-size film piece of a composite film as described above, said film piece comprising a first lateral edge margin and a second lateral edge margin , wherein the two lateral edges margins are joined together by overlapping , the cover film upper surface of the first lateral edge margin being sealed to the base film lower surface of the second lateral edge margin . Th is kind of overlapping is classical , and enables to keep the same side seam specification and integrity as in the state of art.

This receptacle comprises a gap between a lateral f inish of the ink layer and a second lateral edge of the composite f ilm , said ink line extending at least over the whole gap.

And finally, the invention deals with a method for producing a composite film as previously described, wherein it comprises the following steps :

- printing the ink line on the upper surface of the base film ;

- laminating the base film with the cover film ;

- applying the ink layer on the upper surface of the cover film .

The last two steps could be reversed.

A second method for producing such a composite film can be used. Th is second method comprises the following steps:

- printing the ink line on the lower surface of the cover film ;

- applying the ink layer on the upper surface of the cover film ; - laminating the base film with the cover film .

The last two steps could be reversed.

For both methods, there is no need to use specific printing mach ine or tools. It is possible to use known printing technology. There is also no need to develop special ink.

Short description of the drawings

The invention will now be f urther described, by way of example on ly, with reference to the accompanying drawings, of which :

[ Fi g .1 ] figure 1 shows the different layers of a composite film according to a first embodiment of the invention ;

[Fig .2] fig ure 2 illustrates a top view of the composite film of fig ure 1 ;

[Fig .3] figure 3 shows the different layers of a composite film according to a second embodiment of the invention ;

[Fig .4a] figure 4a shows the overlapping of both edges of the composite film of figu re 1 ;

[Fig .4b] figure 4b shows the overlapping of both edges of the composite film of fig ure 1 , with cut edges;[Fig .5] figure 5 illustrates the different steps of a first process for producing a composite film ;

[Fig .6] fig ure 6 illustrates the different steps of a second process for producing a composite film .

Detai led description of preferred embodiment

Fig ures 1 and 3 show a diagrammatic cross section throug h a composite film for tubes in the form of a layer stack of a base film 1 and a cover film 2.

The base film 1 and the cover film 2 are sealable to each other.

The base film 1 has a lower surface 8 and an upper surface 1 0.

The cover film 2 also has a lower surface 1 1 and an upper surface 1 2.

The upper surface 1 0 of the base film 1 is facing the lower su rface 1 1 of the cover film 2. The upper surface 1 0 of the base film 1 and the lower surface 1 1 of the cover film 2 are formed in materials that can be sealed to each other, so as to produce the composite film . It can be the same material or two different materials.

This composite film is used to producing receptacles, in particular tubes that can store cosmetic or pharmaceutic formulas for instance. For this purpose, the composite f ilm is rolled to form a tube which can be connected, leaktight, at its mutually lateral edge margins M 1 , M2 runn ing along the tube axis, in an overlap seam O as depicted in figure 4. The lower surface 8 of the base film 1 and the upper surface 1 2 of the cover f ilm 2 are formed in materials that can be sealed to each other, so as to form the overlap seam O. It can be the same material or two different materials.

These materials consist of thermally weldable materials. The con nection may take place by means of thermal welding , for example high frequency welding , or induction welding .

The material of the upper and lower surfaces of the film base and the film cover is selected from the standpoint of optim um sealing properties and, if appropriate, sufficient transparency.

Preferably, th is material is polyethylene ( PE) . It can be any other suitable material .

Moreover, the material of the cover film upper surface 1 2 is selected from the standpoint of optimum printability. This upper surface 1 2 serves indeed as a print carrier for a decorative imprint. Th is decorative imprint corresponds to an ink layer 7 applied on the cover film upper surface 1 2. It is possible to print bright colors as well as dark colors.

This ink layer 7 is applied on the whole surface, excepted on a first lateral edge marg in M 1 located at the vicin ity of a first lateral edge 9 of the composite film . Th is first lateral edge margin M 1 m ust be free from ink because it will accommodate the opposite second lateral edge margin M2 of the base film lower surface 8, by overlapping as previously explained. The lateral finish 1 6 of the ink layer 7 finishes well before the first lateral edge 9 of the composite film . It is important to leave enough marg in for the overlap seam O, in order to ensure a good welding .

When these two lateral edge marg ins M 1 , M2 are overlapped, an u nprinted gap G can remain between the end 1 6 of the imprint, and the second lateral edge 1 7 of the composite film . This unprinted gap G width is usually comprised between 0,5 and 1mm. This unprinted gap G is illustrated in figure 4a.

For coloring this unprinted gap G, an ink line 13 is added into the composite film. This ink line 13 extends over the whole surface of the unprinted gap G. The ink line 13 extends longitudinally on all the length of the composite film.

More precisely, this ink line 13 is added into the composite film, between the base film 1 and the cover film 2. The ink line 13 can be either printed on the lower surface 11 of the cover film 2, or on the upper surface 10 of the base film 1.

The cover film 2 is chosen so as to have transparency and protective properties. As a result, this ink line 13 is visible through the transparent cover film 2.

The ink line 13 is not located at the same level than the ink layer 7, when observing the thickness of the composite film. But from a user point of view, that looks to the composite film from outside, the ink layer 7 is merged with the ink line 13. The ink line 13 is in the continuity of the ink layer 7 from a lateral point of view.

The ink line 13 has a width L at least equivalent to the width of the unprinted gap G. As depicted in figures 1 and 2, the lateral start 14 of the ink line 13 is aligned with the lateral finish 16 of the ink layer 7. But in figure 3, the lateral start 14 of the ink line 13 starts before the lateral finish 16 of the ink layer 7, for taking a safety margin according to the offset of the ink layer 7 during the process.

The lateral finish 15 of the ink line 13 is at least aligned with the superimposed second lateral edge 17 of the composite film.

But the ink line 13 can be larger than the unprinted gap G, for taking a safety margin according to the offset of the overlapping from one tube to the other. As a result, the lateral finish 15 of the ink line 13 finishes after the superimposed second lateral edge 17 of the composite film. This is clearly visible on figure 4a.

Such a composite film can be used for producing a tube, with a wall consisting of a cut-to-size film piece of said composite film. Said film piece comprises a first lateral edge margin (M1) and a second lateral edge margin (M2). The two lateral edges margins (M1, M2) are joined together by overlapping, the cover film upper surface (12) of the first lateral edge margin (M 1 ) being sealed to the base film lower surface (8) of the second lateral edge marg in (M2) .

These two lateral edges marg ins can be cut at an angle. Usually it is cut at 45 degrees, in order to have a clean side seam , without u nsightly extra thickness, as depicted in fig ure 4b.

Thanks to the composition and the shape of the lateral edges marg ins M 1 , M2, it is no more essential to have an accurate positioning of the two edges when welding them . I n other words, there is a degree of freedom over the relative placement of the lateral edge 9 relative to the lateral edge 1 7.

In all the cases, a tube, formed by this composite film with the side seam , is printed on its 360° surface. When the tube is formed, there is no more visible unprinted space.

Once the overlap is seamed, the whole first lateral edge 9 of the composite film is in contact with the formu la stored inside the tube. For avoiding any ink contamination , the ink line 1 3 fin ishes well before the first lateral edge 9 of the composite film . It is important to leave enough clearance C in order to ensure that the ink line 1 3 will not be into contact with the formu la. Th is clearance C width is preferably comprised between 0,7mm and 2mm . Th is clearance C also enables to avoid delam ination issue of the composite film . This kind of delamination can be observed when the ink line 1 3 it too close from the lateral edge 9, and thus the cover film 2 is not enoug h bonded on the base film 1 nearby the lateral edge 9.

The base film 1 may be designed as a monolayer. However, it can also take the form of a multilayered film . I n this example, the base film 1 comprises a lower layer 3 presenting the lower surface 8, a m iddle layer 4, and an upper layer 5 presenting the upper surface 1 0. Each of these layers 3, 4, 5 assumes functional tasks.

The middle layer 4 can for instance correspond to a barrier layer wh ich prevents the outward migration of substances of the tube contents or else substances from the outside inward.

Furthermore, the base film 1 may carry a metal layer, wh ich may have a barrier function , against humidity for instance.

The base film 1 is preferably a laminated film . The cover film 2 is designed as a monolayer in this example. Flowever, it can also take the form of a multilayered film, but with taking care to keep enough transparency properties, for letting the ink line 13 appear through it. The cover film 2 is preferably a laminated film.

Preferably, the base film 1 thickness is comprised between 200 and

400pm.

Preferably, the cover film 2 thickness is comprised between 15 and

120pm.

Figures 5 and 6 are related to the process for producing a composite film according to the invention.

Figure 5 illustrates a first process, where a base film 1 is unrolled between rollers for printing an ink line 13 on its upper surface 10.

After that, the base film 1 is laminated with a cover film 2, by bringing into contact the cover film lower surface 11 with the base film upper surface 10. The resulting film (1+2) gets through rollers again for printing an ink layer 7 on the cover film upper surface 12.

The resulting composite film is thus ready for tube making. The next step consists in cutting this composite film to produce cut-to-size film pieces for each tube. This cut-to-size film is then rolled and the two overlapped margins are sealed together.

Figure 6 illustrates a second process, where a cover film 2 is unrolled between rollers for printing an ink line 13 of its lower surface 11. After that the cover film 2 gets through a plurality of turning bars so as to reverse it.

Then the cover film 2 gets through rollers for printing an ink layer 7 on its upper surface 12.

After that, the cover film 2 is laminated with a base film 1 by bringing into contact the cover film lower surface 11 with the base film upper surface 10.

The resulting composite film is thus ready for tube making. The next step consists in cutting this composite film to produce cut-to-size film pieces for each tube. This cut-to-size film is then rolled and the two overlapped margins are sealed together. The lamination step of the base film 1 with the cover film 2 is preferably done by extrusion or with solvent.

The printing rollers and mach ines are well-known .

Althoug h the film of the invention has been described above by reference to a specific embodiment shown in the drawing figures, it shou ld be u nderstood that modifications and variations cou ld be made without departing from the intended scope of the following claims.