A LID, PARTICULARLY FOR FOODSTUFF CONTAINERS, AND THE PROCESS USED FOR ITS MANUFACTURE

Abstract: A lid for foodstuff containers includes a shell (3) shaped so that it can be fitted over an opening in a container, and a PVC-free seal (8), bearing an inscription (11), attached to the bottom (6) of the shell (3) and able to seal the lid (1) to the container; the seal (8) is applied to the bottom (6) of the lid (1) by applying adhesive paint (9) between the bottom (6) and seal (8); this paint (9) which can be used to control the adherence of the seal (8) to the bottom (6), consists of a mixture of synthetic resins and hydrocarbons with added metallic pigment; a film (10) bearing the inscription (11) is applied over the paint (9), said inscription made using an ink which has a given chemical-physical affinity with the materials used for the seal (8); it is, therefore, easy to detach the seal (8) from the bottom (6) of the lid (1) upon which the inscription (11) is clearly reproduced.

Description: Description A lid, particularly for foodstuff containers, and the process used for its manufacture Technical Field The present invention relates to a lid, as it is generally known, for foodstuff containers, in particular for use in prize competitions in which an inscription is placed on the inside of the lid. In particular, it should be noticed that the lid concerned may be used to seal glass bottles designed to contain liquid foodstuffs, under pressure or not, which may or may not undergo heat treatment. In such cases, the said lid is a crown cap which guarantees the seal between the air and the container. More precisely, the cap in question has a removable PVC - free seal with an inscription on the side which faces the bottom of the lid. PVC - free means those materials which do not contain polyvinyl chloride, the use of which continues to be reduced, especially in Northern European countries. The afore-mentioned internal inscription makes the lids particularly suitable for use in prize competitions. Background Art At present, in accordance with the prior art and for particular commercial requirements, three different types of caps suitable for prize competitions are used. The first type consists of a cap in the form of a metallic shell, the internal side having a bottom upon which an opaque PVC seal is applied after treatment with adhesive paint. Given its affinity with the paint, the said seal is easily detached, so that an inscription present on the bottom of the cap can be read. The second type of cap, again having an opaque PVC seal, differs from the first in that the inscription is made in such a way that it is transferred from the shell to the seal itself: therefore, this type of cap is ideal for use when the seal must be used as proof of a win, since it is easier to send a seal rather than the entire cap. The third type of cap has a transparent seal (PVC or PVC - free) which cannot be detached from the bottom of the cap. There is an inscription on the bottom of the cap itself, clearly visible through the seal . However, this cap is impractical for use in prize competitions, since the entire cap is required as proof of a win, being less convenient than the second type of cap, since, as already indicated, it is easier to post a seal than a cap. A further disadvantage of this third type of cap is that a sufficiently opaque bottle is required, to prevent the inscription being read from the outside of the bottle. None of the three types of PVC-based crown caps made according to the " prior art can be marketed in those states in which the law forbids the use of PVC crown caps. To comply with such regulations and requirements and, at the same time, obtain a cap which has an easily detachable PVC - free seal, a new technology designed to control the adhesion of the PVC - free material to the cap is needed. Disclosure of the Invention The main object of the present invention is to overcome the afore-mentioned disadvantages of the known types of caps, by providing a cap with a PVC - free seal which, if necessary, can easily be detached from the bottom of the lid shell. A further aim of the present invention is to create an inscription which is easily and clearly transferable to the seal, without the seal adhering to the adhesive paint spread on the bottom of the lid, using a process which is able to control the adhesion of the seal to the shell of the lid. Another aim of the present invention is to provide a simple, reliable operating process. The technical specifications of the present invention and the process used, according to the afore-mentioned aims, are clearly described in the claims, and the advantages are apparent from the detailed description which follows with reference to the accompanying drawings, which illustrate a preferred embodiment, and in which: figure 1 is a schematic plan view from below of the lid disclosed; figure 2 is a schematic view of the lid, according to cross- section II - II shown in figure 1, with some parts cut away to better illustrate others; figure 3 is an enlarged detail of the drawing of the crown cap with detached seal shown in figure 2; figure 4 shows the lid illustrated in the previous figures, in a configuration in which the seal is partially detached and with the transfer of the internal inscription. In the embodiment illustrated, the lid consists of a cap for bottles designed to contain liquid foodstuffs which must not come into contact with the atmosphere. More specifically, it is a crown cap, generally used to seal glass bottles containing liquid foodstuffs which may or may not be under pressure, such as water, wine, various beverages, etc. With reference to the accompanying drawings, the lid disclosed consists of a crown cap, indicated as a whole by the numeral 1. The said cap 1 basically consists of a metallic shell 3, which can be attached to the top of a bottle (not illustrated) , and has a concave surface 5 defining a bottom 6, the edge of which is delimited by a crown 7. The cap 1 also has a PVC - free seal 8 (i.e.: made of a material which does not contain polyvinyl chloride) which is approximately the same size as the bottom 6. Paint 9 is used to stick the seal 8 to the bottom 6 (see figure 2) . More precisely, the method used to manufacture the crown cap 1 in question begins with a sheet of metal. The lithographic print defining the designs which will appear on the outside of the cap (usually the product trade-mark) are made on one side of this sheet of metal, whilst the afore-mentioned layer of paint 9 is spread on the other side. The sheet then goes through the stages of cutting and formation of the shell which create the cap 1. Finally, the cap 1 is passed inside a heating station, where the paint is melted and acts as an adhesive for a seal 8 which is poured into the cap 1, then formed by a corresponding press which gives it the desired shape. For the present invention, the said paint 9 consists of a mixture of synthetic resins and a hydrocarbon compound with added metallic pigment that is neither heavy nor toxic. The addition of the metallic pigment allows the adhesion of the seal 8 to the bottom 6 of the cap 1 to be controlled: the greater the concentration of the metallic pigment in the hydrocarbon compound, the more the paint 9 reproduces the chemical-physical specifications of the metallic shell 3. As a result, the adhesion of the seal 8 to the shell 3 is reduced. More specifically, the metallic pigment may be dosed in such a way as to ensure that the seal 8 remains stuck to the bottom 6 of the cap 1 and, at the same time, make it easy to detach by lifting it off with, for example, a fingernail. The paint 9 described basically consists of the following variable quantities of components, in the weight percentages indicated. - 2-butoxyethanol 15-25% - aromatic hydrocarbons C9-C11 5-15% - n-butanol 1-5% - xylol 1-5% - isobutanol 5-15% - 2 (2-butoxyethoxy) ethanol 1-5% - synthetic resins 30-40% - methyl isobutyl ketone 1-5% - methoxypropanol 10-20% - metallic pigments 1-5% A film 10 of transparent or pigmented material is placed between the paint 9 and the seal 8, said film bearing an inscription 11, obtained using a UV ink. The latter is a special ink, which can be dried and fixed in UV ray ovens. The film 10 is only placed on a limited painted area of the bottom 6 of the cap 1, where the inscription 11 is made. The said film 10 basically consists of organic pigments, aliphatic hydrocarbon fractions, polyester-, amino- and wax resins. Thanks to the composition of the film 10, the inscription 11 with UV ink positioned precisely over the area treated with the film 10 only slightly adheres to the latter and, as a result, adheres much more to the seal 8 with which the inscription is in contact . The UV ink basically consists of: organic pigments, amino- and/or polyester- and/or epoxy- resins, acrylic oligomers consisting of di- and tri- esters of polyfunctional alcohols with acrylic acid, benzophenone and/or complex ketones or their derivatives, polyethylene waxes. The following is a description of the process for the creation of the structure of the lid 1. First, the paint 9 is prepared by mixing the synthetic resins with a hydrocarbon compound to which a metallic pigment has been adde . Then, the paint 9 is spread on one side of a sheet of material, normally metallic, with mechanical specifications suitable for obtaining the shell 3 of the cap 1. Depending on specific requirements, the said sheet consists of chrome-plated steel, tin-plated steel, or stainless steel and aluminium. The paint 9 is then dried in conventional ovens at temperatures which vary between 150 and 250°C, this drying process lasting 5 - 20 minutes. The temperature is preferably kept within the smallest interval of 180 - 190°C for a period of 11 - 13 minutes . In a later stage of the process, if the cap 1 is to be used to set commercial prize competitions, the film 10 is applied over the paint 9. It is applied by using a special lithographic plate to lay the said film 10 only in the painted areas in which the inscription 11 is to be obtained. The film 10 is then dried in a second drying operation, identical to that used to dry the paint 9. In another stage, the inscription 11 is made on the painted areas covered by the film 10. The inscription 11 is preferably made using the same plate that was used to apply the film 10, and using UV ink with the afore-said specifications and composition. The sheet thus treated is ready to be cut, thus obtaining the shells. A PVC - free seal 8 is attached to each of the shells, so as to guarantee the seal between the cap 1 and the bottle. The above description clearly indicates one of the advantages of the present invention. That is to say, when the seal 8 is detached from the bottom 6 of the cap 1, the seal bears a clear reproduction of the desired inscription 11 (as shown in figure 4 ) . The use of a paint which contains a metallic pigment allows the stage in which the seal is detached from the lid to be controlled, leaving the mechanical specifications and seal of the crown cap as a whole unchanged, this being an important factor for the bottlers who use it . In particular, this bilateral control of the adherence of the seal to the lid and limited adherence of the writing to the bottom of the lid is, above all, a result of the identification of components suitable for obtaining a substance compatible with and acting upon the PVC - free material, without the latter losing any of the advantageous specifications present. The present invention may be subject to numerous modifications and variations, all of which are encompassed by the design concept. Moreover, all parts may be substituted with technically equivalent parts.

Claims: Claims 1. A lid for foodstuffs of the type which includes: - a shell (3) shaped in such a way that it can be fitted over an opening in a container, said shell having a bottom (6) whose shape corresponds to the mouth of the container, said bottom (6) facing the inside of the container when the lid (1) is closed; - a seal (8), of the PVC - free type, said seal being attached to the bottom (6) and sealing the lid (1) onto the container; - an adhesive paint (9) applied over the surface of the said bottom (6) to join the seal (8) to the bottom (6), characterised in that the said paint (9) includes a hydrocarbon compound with at least one metallic pigment, so that the seal (8) can, if necessary, easily be detached from the bottom (6) of the shell (3) . 2. The lid as described in claim 1, characterised in that the paint (9) basically consists of the following components: 2- butoxyethanol, aromatic hydrocarbons C9-C11, n-butanol, xylol, isobutanol, 2 (2-butoxyethoxy) ethanol, synthetic resins, methyl isobutyl ketone, methoxypropanol and metallic pigments. 3. The lid as described in claim 2, characterised in that the components of the paint (9) are respectively present in the following weight percentage intervals: 2-butoxyethanol 15-25%, aromatic hydrocarbons C9-C11 5-15%, n-butanol 1-5%, xylol 1-5%, isobutanol 5-15%, 2 (2-butoxyethoxy) ethanol 1-5%, synthetic resins 30-40%, methyl isobutyl ketone 1-5%, methoxypropanol 10-20% and metallic pigments 1-5%. 4. The lid as described in claim 1, characterised in that the seal (8) is easily manually detached from the bottom (6) of the shell (3) . 5. The lid as described in claim 1, characterised in that an inscription (11) is reproduced on the part of the seal (8) which adheres to the paint (9) on the shell (3), and that at the said inscription (11) a non-stick film (10) is positioned between the paint (9) and the inscription (11), to reduce the adhesion of the inscription (11) to the paint (9), thus creating greater adhesion to the seal (8) side. 6. The lid as described in claim 5, characterised in that the film (10) consists of organic pigments, aliphatic hydrocarbon fractions, polyester-, amino- and wax resins. 7. The lid as described in claim 5, characterised in that the film (10) is made of a transparent material. 8. The " lid as described in claim 5, characterised in that the film (10) is made of a pig ented material. 9. The lid as described in claim 5, characterised in that the inscription (11) is made using a UV ink which can be dried in UV ray ovens . 10. The lid as described in claim 9, characterised in that the said UV ink consists of: organic pigments, amino- and/or polyester- and/or epoxy- resins, acrylic oligomers consisting of di- and tri- esters of polyfunctional alcohols with acrylic acid, benzophenone and/or complex ketones or their derivatives, polyethylene waxes . 11. The lid as described in claim 1, characterised in that the lid (1) consists of a bottle cap including a shaped metallic shell (3), preferably in the shape of a crown (7) and a seal (8) which does not contain polyvinyl chloride. 12. The lid as described in claim 1, characterised in that the metallic pigment consists of a metal which is neither heavy nor toxic. 13. Process for making a lid according to claims 1 to 12, characterised in that it includes the following operating stages: - mixing of synthetic resins with a hydrocarbon compound to which at least one metallic pigment is added, to obtain the paint (9); - spreading of the paint (9) on one side of a sheet of metal suitable for making the shells; - drying of the paint (9); - application of a film (10) over the paint (9) in the areas in which an inscription (11) will be positioned; - drying of the film (10); - creation of the inscription (11) in the areas in which the film (10) is applied, said inscription (11) adhering less to the film (10) placed over the paint (9), than to the seal (8) which is then laid over it; - cutting and forming of the shells (3) into the desired shape; - application of the seal (8) to the bottom (6) of the shell (3) over the inscription (11) . 14. The process as described in claim 13, characterised in that the film (10) is applied using a first plate. 15. The process as described in claim 13, characterised in that the drying stages are carried out at temperatures which vary between 150 and 250°C and with drying times of 5-20 minutes. 16. The process as described in claim 13, characterised in that the inscription (11) is applied using a second plate. 17. The process as described in claim 13, characterised in that the film (10) and inscription (11) are applied using the same plate. 18. The process as described in claim 13, characterised in that the inscription (11) is printed in UV ink.

Inventors: FOLCHINI ENRICO, MICHELINI FABRIZIO, SCHIARETTI MARZIANO, FOLCHINI, ENRICO, MICHELINI, FABRIZIO, SCHIARETTI, MARZIANO
Applicants: FOLCHINI ENRICO, MICHELINI FABRIZIO, PELLICONI & C SPA, SCHIARETTI MARZIANO, FOLCHINI, ENRICO, MICHELINI, FABRIZIO, PELLICONI & C. S.P.A., SCHIARETTI, MARZIANO
Application year: 1997
Main classification: B65D41
IPC codes: B65D41, B65D51, B65D53, C08K3, C08L61, C08L67, C09D5, C09D11