Translucent Gasket Comprising A Watermark That Is Not Visible In Reflected Light

Abstract

The invention relates to a light-transmitting gasket intended to be positioned on the base of a stopper or cap, in the form of a support having a light-transmitting coating applied to at least one of the surfaces thereof. The gasket is characterised in that the coating contains a watermark, i.e. an image visible in transmitted light, but not visible in reflected light.

Description

[0001] The subject of the invention is a novel gasket whose essential characteristic is to be provided with a watermark.

[0002] In the remainder of the description and in the claims, the term "watermark" denotes a drawing or an image that is observable or visible in transmitted light. By "observable or visible in transmitted light" is meant an element (here the watermark) that it is visible, in particular with the naked eye, when placed between the eye of the observer and a light source, so that the eye perceives the rays of the light source through the observed element. In practice, the watermark is visible by transparency in visible light, that is to say at a wavelength between 380 and 780 nm.

[0003] The watermarks are visible in transmitted light, but they are not visible in reflection, i.e. when the eye of the observer and the light source are placed on the same side of the element to be observed, so that the eye perceives the rays of the light source reflecting on the observed element.

[0004] The seal of the invention is of the type used for the sealing of consumer products, in particular in the food or cosmetic industry.

[0005] These include notably a one-piece gasket. In a known manner, the one-piece gasket consists of a foamed or non-foamed support. In the case of foam, they are foams of polypropylene (PP), polyethylene (PE) or polyethylene terephthalate (PET), optionally laminated with PP, PE or polyethylene terephthalate (PET). The purpose of these seals is to ensure the sealing of the packages against, first of all, the content, liquid or not, but also against the oxygen, as well as against aromas and odors.

[0006] These seals are usually delivered to the stopper or cap manufacturer. The manufacturer inserts them at the bottom of a stopper or a cap and delivers them to the final customer. The final customer fills the containers (flacon, bottle, pot . . . ) and then closes them by means of the stopper or the cap provided with its joint.

[0007] The invention also relates to the double-piece joints intended to be glued or sealed on the container lip. These seals consist of two parts, respectively a lid and a support. The lid is placed over the entire periphery of the upper rim of the finish of the container or a lip, thus isolating the container from the outside. The support is generally thicker. It is inserted, without being fixed, at the bottom of the cap. Prior to the first opening of the container, the support and the lid may be secured by means of a temporary adhesive. We can distinguish double-piece joints that are glued or heat-sealed.

[0008] With regard to the glued double-piece, the bonding is conventionally carried out by means of glue compatible with the lip and the underside of the lid.

[0009] When the seal is intended to be sealed on the container, it has a sealing layer applied on its underside. Sealing is performed by induction heat sealing through the cap. This heat sealing is made possible by the combined action of a conductive material inserted into the thickness, preferably of the cap, which, as an effect of the magnetic induction, heats, causing the melting of the sealing film on the lip.

[0010] The distribution channel of these joints is identical to that functioning and described previously for one-piece gaskets.

[0011] Numerous solutions have been proposed to make it possible to verify that the product purchased by the consumer was an original product and/or had never been opened.

[0012] As an example, in the field of wine stoppers, document US2003/0127846 describes an anti-counterfeiting device in the form of sealing strip inner face of which is covered by an image appearing only on contact with oxygen. As the strip is removed, the image, in particular the brand of the beverage, is revealed in contact with the oxygen.

[0013] Document US Pat. No. 2014/0224800 describes a double-piece gasket of the lift n peel.RTM. type, where one of the layers of the lid is covered with a hologram. The hologram appears when the lid is removed, which guarantees the origin of the product. Moreover, the application of the hologram over the entire surface of the layer, including on the part secured to the lip, means that the membrane cannot be put back once separated. Therefore, the described seal makes it possible to guarantee the inviolability of the product.

[0014] For manufacturers of cosmetic and food products it is essential to guarantee the consumer the origin of the products and their inviolability. From the manufacturer's point of view, it is also essential that the seal supplied to him comes from the original joint manufacturer. Since most of the time the joints are not delivered to the manufacturer of the final product directly by the joint manufacturer but by an intermediary manufacturer of the stopper, there is a risk that the joint that is inserted in the stopper is not the original one. Taking into account the specificity of the joints as an oxygen, aroma, odor barrier, depending on the nature of the product to be protected, it is easy to imagine the consequences of inserting a joint not responding to the specific requirements.

[0015] The necessary solution is the marking of the joint to represent the joint manufacturer. The constraint for the consumer product manufacturer is that he does not wish that this marking be visible to the final consumer. This is not desirable, apart from the aesthetic aspect that could be affected.

[0016] Document U.S. Pat. No. 3,628,271 describes a stopper outer surface of which is covered with a layer revealing an expiration date under UV light.

[0017] Document U.S. Pat. No. 7,789,074 describes a gasket consisting of a compressible layer on which a transparent film is applied. The compressible layer is structured. It is in the form of a series of extruded filaments. The structure of the compressible layer is visible in reflection whatever the side of the joint so that it is not a watermark.

[0018] The problem which the invention proposes to solve is to develop a gasket provided with an identification means that is not visible to the consumer.

[0019] To do this end, the Applicant had the idea to integrate a watermark into the thickness of the gasket.

[0020] More precisely, the subject of the invention is a light transmitting gasket, in practice visible light, intended in particular to be inserted at the bottom of a cap or a stopper in the form of a support transmitting itself the light and advantageously made of a foamed material on at least one of the faces on which is applied a material, referred to in the remainder of the description and in the claims by the term "coating" and also transmitting the light.

[0021] This gasket is characterized in that the face of the support on which the coating is applied, and more precisely the coating itself, has a watermark, that is to say an image visible in transmitted light and not visible in reflection.

[0022] According to the invention, the gasket of the invention is a one-piece gasket or the support part of a double-piece gasket.

[0023] In the case of a one-piece gasket, whether it is the stopper or cap manufacturer or the manufacturer of the final product, who receives the stopper+seal assembly or, more rarely, the seal directly, all of them can perfectly identify the origin of the gasket. In the case of a double-piece seal, the identification of the joint, in practice of its support, can only be carried out after the support has been separated from the lid.

[0024] In fact it is sufficient to place the gasket between the eye and a light source to detect the watermark pattern. The term "drawing" of course covers any type of marking, whether it is a logo, a name, a drawing, an image, a pattern, etc.

[0025] As already mentioned, the verification can be done directly when the joint is a one-piece gasket. In the case of a two-piece gasket, verification can be carried out after separation of the support and the sealing cap or without prior separation if the seal is not completely opaque.

[0026] According to a first embodiment, the material constituting the support is an foamed material that is preferably chosen from the group comprising low density polyethylene (PE), polypropylene (PP), PET, polystyrene (PS). In practice, the density of the foam is between 30 and 500 kg/m.sup.3, advantageously between 150 and 400 kg/m.sup.3, that is to say an average density.

[0027] According to another characteristic, the thickness of the foam is advantageously between 1 and 3 mm.

[0028] According to a second embodiment, the material constituting the support is a non-foamed material which is preferably chosen from the group comprising polyethylene, polyethylene copolymers, thermoplastic elastomers, PP, PET, PS. In practice, the density of the support is in this case between 800 and 1500 kg/m.sup.3.

[0029] In the two previous embodiments, the support is extruded, in view of the nature of the materials used.

[0030] In another embodiment, the support is made of a non-foamed, non-extruded and light-transparent material. It may be, for example, cardboard with a density advantageously between 40 and 600 kg/m.sup.3.

[0031] According to the invention, the light-transmitting coating applied to the support comprises a paper sheet and/or at least one polymer film.

[0032] In a preferred embodiment, the light transmitting coating comprises at least one polymeric film.

[0033] In practice, the polymeric film is chosen from the group comprising PET, PVDC, PP, polyester, PA (polyamide), PE (polyethylene). The film preferably has a thickness between 5 and 100 micrometers.

[0034] In one particular embodiment, the light transmitting coating comprises two polymer films.

[0035] They can be two coextruded films or two films associated by means of an adhesive. In a particular embodiment, the light transmitting material is a complex consisting of a polyester top film and a polyethylene bottom film.

[0036] The two films once associated are then calendared or laminated onto the support.

[0037] The light transmitting coating is applied to one or both sides of the support that can be extruded or not. When the support, extruded or not, is covered only on one side, the watermark is applied to the face comprising the light-transmitting coating.

[0038] The seal can be positioned at the bottom of the stopper or cap in any direction.

[0039] Of course, the shape of the joints of the invention will be determined as a function of the shape of the stopper or of the cap.

[0040] According to an essential characteristic, the light transmitting coating has a watermark. This watermark can be obtained in various ways, recalling that, by definition, it is a pattern visible in passing light.

[0041] In a preferred embodiment, the light transmitting coating is white in color and the foamed or non-foamed material is advantageously also white in color. At the same time, the watermark is in the form of a white print and is preferably applied to the back of the light transmitting coating. In this case, the coating is advantageously a polymer film.

[0042] Finally and according to another feature, the watermark is applied between the support and the light-transmitting coating, in particular the film. As already stated, the watermark, that is to say an image visible in passing light and not visible in reflection, is preferably applied to the back of the light-transmitting coating.

[0043] The invention and the advantages thereof will become apparent from the description which follows.

[0044] A repeated pattern of white color is printed on a strip of white PET polymer film. The PET film has a thickness of 25 microns.

[0045] This strip of film is laminated on a white foamed PE strip. The foam has a thickness of 1 mm and a density of 200 kg/m3.

[0046] The gaskets of the desired size are cut out in the thickness of the complex obtained.

[0047] If the gasket is placed between the eye and a light source, the watermark is visible between the support and the light transmitting material.

[0048] The invention and the advantages which result therefrom are well apparent from the foregoing description. In particular, it is possible to guarantee the manufacturers of consumer products the origin of the gaskets used in the packaging.

Claims

1. A light-transmitting gasket intended in particular to be inserted at the bottom of a stopper or cap, in the form of a support on at least one of the faces of which a light-transmitting coating is applied, characterized in that the coating contains a watermark, that is to say an image visible in transmitted light and not visible in reflection.

2. The gasket according to claim 1, characterized in that the light-transmitting coating comprises a paper sheet and/or at least one polymeric film.

3. The gasket according to claim 1, characterized in that the support is made of a foamed material and is advantageously chosen from the group comprising low density polyethylene (PE), polypropylene (PP), PET, and polystyrene (PS).

4. The gasket according to claim 3, characterized in that a density of the foamed material is between 30 and 500 kg/m.sup.3.

5. The gasket according to claim 3, characterized in that thickness of the foamed material is between 1 and 3 mm.

6. The gasket according to claim 1, characterized in that the support is made of a non-foamed material and is advantageously chosen from the group comprising polyethylene, polyethylene copolymers, thermoplastic elastomers, PP, PET, and PS.

7. The gasket according to claim 6, characterized in that the material has a density between 800 and 1500 kg/m.sup.3.

8. The gasket according to claim 1, characterized in that the support is made of a non-foamed, non-extruded material.

9. The gasket according to claim 8, characterized in that the paper has a density between 40 and 600 kg/m.sup.3.

10. The gasket according to claim 2, characterized in that the polymer film is selected from the group comprising PET, PVDC, polyester, PP, PA, and PE.

11. The gasket according to claim 2, characterized in that the polymeric film is white in color.

12. The gasket according to claim 2, characterized in that the watermark is in the form of a white-colored printing.

13. The gasket according to claim 1, characterized in that the watermark is in the form of a printing applied between the support and the light-transmitting coating.

14. The gasket according to claim 1, characterized in that the watermark is applied to the back of the light-transmitting coating.

15. The gasket according to claim 8, wherein the material comprises paper.