The present invention relates to an electronic device comprising an RFID tag inserted in a waterproof casing. The use of RFID technology is well known and widely spread, it allows the identification and automatic storage of information about objects, animals or persons, based on the data storage capacity, by special electronic tags (or transponders), and on their ability to respond to the remote query by special readers. The latter can not only read the data stored on the tag memory, but also write new ones on it.

In the case of passive tags, the structure comprises a microchip (with unique identifier and memory) ; no power supply; a flat and thin antenna, of suitable impedance at the different range of selected frequencies; a material that acts as a physical support (generally based on one or more layers of polymeric or paper film) .

An external reader emits an electromagnetic signal at low, medium, high or very high frequency, operated manually or automatically, by radio-induction it excites the antenna at a distance of a few millimetres, and up to some metres, depending on the selected frequency band. This pulse activates the microchip and provides the energy needed to respond to the reader, resending a signal to it that carries the information contained in the chip. Likewise, the reader can write data on the tag. The applications are endless. They range from the identification of objects or animals, to credit cards, electronic toll collection apparatus, passports, car opening keys, hotel locks. Their use in logistics is important: identify containers stored in the racks and provided with tags, it reduces errors in picking, eliminating the need to open the packages.

A great advantage of RFID technology, compared for example to that of bar codes, is that it is not necessary for the reader to physically "see" the tag. Antennas suitable for low, medium, high or very high frequencies can allow reading at a few centimetres, as well as at a few metres away (car keys, warehouse shelves) . In particular, for industrial laundry activities, it is advantageous to use very high frequencies, around 860/960 MHz, capable of reading distances of the order of some metres. The simultaneous reading of a plurality of tags is also possible. Conversely, for other uses, reading at few centimetres is preferable (objects stored in compact shelves; this prevents the undesired reading of other adjacent devices), in which case HF tags are used (around 13.56 MHz) .

For example, an application in the field of industrial laundry is known. The devices are protected by sealing them within a special sheath, consisting of two layers of thermoplastic film (PU, PVC) , made by high-frequency welding or pressing, and subsequent die-cutting. Such assembly, not permeable to water, is applied to fabric items intended for repeated usage cycles, and as many cycles of washing, drying and ironing (e.g.: in large hotel complexes, linen bed and towels that in thousands have to be washed every day; in barracks, prisons, industrial laundries; on cruise ships) . The microchip, which already contains its indissoluble identification code, through pulses transmitted by the reader via an antenna, is then able to store information about the subsequent washing cycles, for example the numeral order of the cycle, date, duration, temperature, type of soap used. This also applies to drying and ironing. When the washed, dried and ironed item is stored, for example in special racks, it is possible with the aid of the reader, manually or electronically operated, to read the stored information and derive appropriate decisions: for example, if the washing cycles reach predetermined amounts, taking into account also the durations and temperatures, one can decide whether to carry out a check of the wear, or the item should be sent to discard, etc.

Another possible application is for the production of tissue reels: a device applied on a reel can store and transmit information about the production technology, washings, dyes, with recording of times and temperatures. Everything with absolutely automatic control insertable in the production technology. Another example of application is the tracking of objects or containers located, in ordered amounts, within adapted shelves, almost in contact with one another. In this case, HF devices are preferred, applied on the containers, suitable for being "read" at a short distance: without the risk of confusion with the devices applied on neighbouring objects.

While the current technology is widely applied, it still has serious drawbacks mainly related to the poor quality of the antennas used. In a particular embodiment type, the devices are similar to adhesive labels. They include the antenna, of thickness in the order of hundredths of a mm, of a conductive metal sheet, made with the etching technique: one starts from a polymeric film coated with a thin layer of metal or conductive alloy; the superfluous metal with respect to the desired antenna geometry is removed by chemical or galvanic technology. Then, the antenna thus created is connected to the microchip, by gluing with conductive resins; subsequently sheared to form a support label made of a thermoplastic film (e.g. PBT or polyester) having a thickness of about 0.1 mm; width of between 8 and 50 mm, and length of between 30 mm and 80 mm. However, the cases of damage of the antennas contained in the labels during use in laundries are very frequent .

The twists suffered during washing, and especially the intense compression stresses on the fabric items when, under the squeezing presses, are piled and twisted in random position, causing after a few washings serious microcracks of the tracks of metallic films that constitute the antenna, thus changing the impedance thereof or completely interrupting the electrical transmission .

Another embodiment provides that the tag is inserted into casings of flexible thermoplastic polymer sheet. The tag is enclosed in an envelope of polyurethane film (TPU) or plasticised PVC made by superimposing two portions of transparent thermoplastic polymer film of thickness for example comprised between 0.3 mm and 1.5 mm) , and high-frequency welding them along the perimeter, or cold or hot compressing them. At the end, the assembly is punched to the final dimensions.

The label thus produced is hermetically resistant to the penetration of water, but only on condition that the high-frequency welding is perfect, and has not degraded the polymer itself, or electromagnetically damaged the microchip. But above all, none of the thermoplastic polymer films usable withstands repeated washings at temperatures above 60/70 degrees centigrade, just as thermoplastic, it softens and loses its mechanical characteristics.

The welding frame is even less resistant, as a result of which the molecular structure of the polymer is often degraded. Everything, as verified under "fatigue", that is, through repeated thermal cycles, exhibits a worrying percentage of mortality already when subjected to a number of washes exceeding 10.

Also extremely critical are drying and ironing processes, with serious risk of damage to the items and in any case inability to operate at the correct temperatures. Now, it is easy to imagine what the damage is in case of a tag deteriorated by subsequent washes at slightly high temperatures, or by water infiltrations: loss of initial or subsequently inserted data; need to discard the whole item or remove the damaged tag and replace it with a new one; transcription of the data stored in the old tag to the new tag, if saved; all with forced interruption of the automatic washing procedures. Probably the lowest cost will be to discard the whole item. Another drawback is that the thermoplastic polymers used (TPU or PVC) may cause, especially at high temperatures, the migration of plasticisers that are likely to stain or deteriorate the fabrics in direct contact with them. Moreover, sheared or punched edges are sharp and aggressive for the fabrics with which they are in contact.

Injection moulded casings of thermoplastic material (polyurethane, thermoplastic rubber TR, PVC) . In the first place, the technology requires that the melt is injected in contact with the tag at the melting temperature, between 170° and 250°; it is easy to imagine how such a hot flow can damage the delicate antenna. Then in use, the label at the high temperature of industrial washing will soften and lose mechanical strength; when squeezed in presses in wringing mangles, it will assume permanent deformations with considerable negative effects on the mechanical strength and on the impedance of the antenna contained therein. Application method to the fabric item. Labels are usually either heat fused on the fabric item (by a thermal adhesive film and by simple ironing) ; but after a few washings, adherence ages and the label comes off, or they are sewn directly at the edge of the item; or introduced in fabric envelopes, then closed and sewn to the item. In these two cases, in order to remove and control a label no longer functioning, expensive operations of unstitching and re-stitching are required, not to mention that in many cases, instead of unstitching a hasty operator will cut the envelope, at risk of also definitely damaging the tag.

In the case of HF tags to read from a very short distance, the most common structure consists of a flat rigid PVC disc, about 1 mm thick, of variable diameter between 10 and 70 mm; or by a rectangle of comparable size. The antenna is located inside, contained and protected by the various layers of which the disc is made, usually consisting of a microchip and a circumferential coil of copper wire. The assembly on the objects to be tracked takes place either by double- sided adhesive films or by mechanical joint. The problem is that rigid PVC is characterised by a softening temperature at just 60/70°C. At higher temperatures, nothing protects the tag from any deformation which, however minimal and even if not destructive, modify the antenna geometry and "deform" the reading. The system works only if any mechanical stress is strictly avoided. At high sterilisation temperature (125 °C) , the tag is absolutely exposed to the sudden change in temperature and to the high steam temperature. Moreover, the adhesive films used for connecting tags to the objects to be tracked may form agglomeration points for pollutants or infectious substances .

US Pat. 6, 233, 818 (Finn et al . ) describes the methodology for the construction of a type of tag in which the antenna is made of copper wire, and related machinery. No device is provided to make the tag suitable for use for industrial laundries: no encapsulation is provided that prevents contact with water, which moreover is at high temperatures and added with detergents; no protection is provided against breakages due to the very strong squeezing pressures that are created in the wringing machinery, nor for the high ironing temperatures.

Likewise, WO97/30418, EP1842405, WO2006/063652,

WO2010/035235, EP2534932, which describe various manufacturing technologies for tags with copper wire antenna without proposing any feature that allows using these tags in industrial laundries are not significant in the prior art.

Similar considerations for patents EP2306371 Bl, EP2340513, WO20100079459, WO2010 089 713, which relate to various types of tags with copper wire antenna, and their production technology, without, however, describing any special measures aimed to a specific use in industrial laundry, such as protecting them from the environment characterised by warm water and detergents, strong squeezing pressures in presses and ironers, high ironing temperatures.

CN Patent 101826163 describes a type of tags in which the central layer (which contains antenna, microchip and support) is protected by inserting it between two layers of already vulcanised silicone rubber. In order to obtain the adhesion, a uniform thickness of unspecified transparent glue is put on the inner faces of these layers. The sandwich is then hot pressed and punched together. It is clear that the hermetic seal will always be conditioned by the unreliable adhesion of glues with the silicone rubber, and that the construction process required is extremely wasteful. The antenna is of the aluminium foil type, so-called "hetched", not resistant to pressing and squeezing stresses typical of industrial laundry.

CN Utility model 201654823 appears absolutely identical to the aforementioned patent, to which it adds nothing. CN Model 203825654 describes tags resistant to high temperatures, as they use sandwiches of several layers of materials, such as epoxy resins and/or silicone (and therefore resistant to high temperatures; but the adhesion between the various layers is unreliable, as generically and summarily solved by unidentified "adhesives") . Finally, there remain serious problems of cost also due to the bonding technology of the various superimposed layers.

US Patent 2004/0094949 Al instead describes a device that contains the tag and somehow protects it from the external environment. The real tag is the antenna assembly that is laminated on both sides with adhesive films, which can be activated by heat. On one side, it is then protected with a thermoplastic film. Then inserted in a mould suitable for the "in mould" technology, with the protective film in contact with the cold wall of the mould. The mould is closed, and a suitable quantity of thermoplastic polyolefinic polymer is injected on the free wall, in contact with the thermal adhesive film that covers it, which should seal everything. Reasonable doubts remain on the resistance of this multisandwich of thermoplastic layers and thermo-adhesive films, when the labels applied to the items to be washed are subjected to repeated steps in water at high temperature and to detergent charge; to high squeezing pressure; and to high ironing temperatures .

The purpose of the present invention is to solve the aforementioned problems by selecting and describing a type of UHF tag suitable for use in industrial laundry and more. That is, designed as an antenna and as a selection of the microchip to be "read" at distances ranging from 40 cm and 4/5 metres. That has a suitable structure for making it bear significant mechanical stresses, such as washing and especially squeezing in presses or wringing mangles and subsequent drying.

The purpose therefore is to provide a casing or label encasing the tag, which makes it always and positively protected by means of a monobloc sheath hermetic to water and soap infiltrations and to chemicals; resistant to temperatures above 125°C which are characteristic of steam sterilisation; resistant to high pressures developing in wringing machines (presses and mangles); flexible; resistant to mechanical deformations; permanently elastic so as to immediately recover its original shape even after deformation (bending) long protracted over time, and/or at high temperatures; possibly transparent; adapted to not disperse pollutants on the fabric. A casing that, in order to achieve the above purposes, a) is shaped into suitable shapes in a dedicated mould and b) is made of raw silicone rubber pliable prior to moulding and then vulcanised, which transforms it into the final, resistant and elastically non-deformable material par excellence .

Such a casing or sheath is not an envelope consisting of several layers of films or sheets glued or welded together, as in the prior art, but is instead a single silicon rubber block, in the shape of small plate, perfectly homogeneous in the mass and consistent with itself at each point.

In this way, tags where the antenna is single-wire or multi-wire, of copper or other conductive metal, moulded and anchored on a paper or plastic or rubber support, with microchip mechanically and electrically connected to the antenna by welding or electro- conductive adhesive, are suitable.

The object of the present invention is an electronic device comprising a casing which encloses an RFID tag and a method for making such a device as indicated in the appended claims.

The features and the advantages of the present invention will be specified in detail and highlighted in the following non-limiting exemplary description, and in the accompanying figures which show, respectively :

• figure 1 shows a prior art tag made with "etching" technologies and enclosed between two electrically welded layers of TPU;

• figure 2 shows an RFID tag adapted to implement the present invention;

• figure 3 shows a perspective view of the device according to the present invention used for industrial laundry;

• figures 4a and 4b show the device of figure 3 in sectional and exploded view;

• figure 5 shows the device contained in an envelope to apply it to a piece of clothing;

• figure 6 shows a device according to a further embodiment of the present invention, in particular for tracking objects;

• figures 7a and 7b show the device of figure 6 in sectional and exploded view;

• figure 8 shows the mould needed to make the device of figure 6; • figure 9 shows the mould needed to make the device of figure 3.

Figure 2 shows a tag 1 yet devoid of encapsulating sheath comprising an antenna 11 for radio frequency, made of a copper microwire; and a microchip 12 glued and electrically connected thereto inserted in a support film 13, usually of paper or polymeric material (e.g. : PBT) .

Figure 3 shows a device 2 according to the present invention in which the tag is not visible and is perfectly embedded in a vulcanised silicone rubber block. It is clear that the dimensions of the device in length and width must exceed the corresponding dimensions of the tag by several millimetres, so as to allow the formation of a frame, of a width preferably at least greater than 1 mm.

Figure 4 shows two sectional views of the same device, in which the casing comprises a pre-moulded base 21 in which a seat 22 is provided for housing tag 1 inside which a shield 23 can optionally be inserted.

This base is closed during the vulcanisation by a lid 24 which is moulded on the base during the vulcanisation step. The base ends, due to suitable fittings, cause the peripheral borders 25 of the device to be rounded, instead of having a cutting-edge as in many cases of the prior art, thus being non-aggressive for the fabric items on which they will be applied. It is also noted that a suitable relief 26 is formed at said seat on the outer surface of the device.

Figure 9 shows the mould for making such a device which comprises two halves, an extraction part 31 and an injection part 32 comprising an injection hole 33. On such halves, the two impressions 34 and 35 are visible, which are intended to receive the assembled device as shown in figure 3 before vulcanisation. The injection hole 33 is necessary only in the case of injection moulding; it is not necessary for compression moulding. When the mould is closed, the necessary amount of silicone rubber is injected through the injection hole to form lid 24, which co-vulcanises with the other silicone parts and creates the soft, monolithic and hermetic block.

Figure 5 shows a particular example of a textile envelope 4 intended to assemble device 2 on a textile garment. The envelope is made of fabric, advantageously of the ultrasound weldable type. Seals 41 and 42 form a compartment 43 for containing the device. The outer flap 44 is used for sewing the envelope on the items to be tracked.

The width L of the inner compartment is precise with respect to the device, but two slightly more narrow passages are left open at the two ends 45 and 46, so that during the washing steps, the device is certainly held inside of the envelope, but it is also possible, during maintenance and control, to bend the silicone rubber wings and remove it from the envelope, to check it and then re-insert it into place, or replace it, if necessary .

Figures 6-8 show a second embodiment of the invention in which the device may be used for tracking objects. Tag 6 may be described as a rigid PVC disc and device 7 is made by incorporating the tag in its interior, i.e. in a block of silicone rubber which preferably will have a total thickness of between 3 and 6 mm.

The disc preferably has a diameter of between 10 mm and 90 mm, and a thickness of between 0.8 and 5 mm.

As in the previous embodiment, the device comprises a pre-moulded base 71 in which a seat 72 is provided for housing tag 6 inside which a shield 73 made of pre- moulded silicone can optionally be inserted.

This base is closed during the vulcanisation by a lid 74 which is moulded on the base during the vulcanisation step. The base and the shield have the function of supporting "sandwich-like" the tag during moulding, and to thermally isolate it from the mould walls .

Figure 8 shows the mould for making such a device which comprises two halves, an extraction part 81 and an injection part 82 comprising an injection hole 83. On such halves, the two impressions 84 and 85 are visible, which are intended to receive the assembled device as shown in figure 6 before vulcanisation. The injection hole 83 is necessary only in the case of injection moulding; it is not necessary for compression moulding. When the mould is closed, the necessary amount of silicone rubber is injected through the injection hole to form lid 74, which co-vulcanises with the other silicone parts and creates the soft, monolithic and hermetic block.

The first embodiment provides that the device comprises an RFID tag with a UHF antenna (remote reading) for frequencies close to 860 MHZ and a microchip, preferably both supported by a support of paper or polymeric film or equivalent. In the second embodiment, the tag is preferably of HF type (close reading) for frequencies around 13.56MHz, in which the antenna and the microchip are contained within a sandwich of layers of rigid PVC or equivalent.

Suitable silicone rubber types for the tag incorporating casing belong to the category of the HTV (High Temperature Vulcanizing) paste silicones or of the LSR (Liquid Silicon Rubber) silicones, whether they are of the peroxy or platinum catalyst type or of any type, and have a hardness comprised between 10 and 95 Shore A.

During the vulcanisation in the mould, the molecular cohesion between the various parts of the silicone casing is ensured by the vulcanisation process, during which the pre-existing molecular chains in the raw polymer are connected and joined by additional chains, thus creating a single mass having its elastic consistent shape, impervious to water also under pressure, resistant to chemical agents, ageing and mechanical stress.

The operations described are, in whole or in part, carried out automatically, with automatic presses, automatic drive and extraction moulds, Cartesian or anthropomorphic robots, multiple stores for tags with translating or rotary tables; labelling machines; thus limiting human intervention as much as possible; and possibly automating the radio frequency control before and/or after moulding.

The shield may be made, for example, of polyamide or polycarbonate or high hardness silicone, designed to shield the microchip from excessive mechanical and/or thermal stress both during moulding and during use in laundry; preferably, if for laundry, of limited extension to only protect the most sensitive areas

(surrounding the microchip) without affecting the good flexibility of the label as a whole; advantageously, the shields may also consist of portions of film, of appropriate strength, flexibility and thickness, adhered to the most delicate areas of the tag. In the case of HF tags embedded in rigid PVC discs or the like, these shields may advantageously be previously made of silicone rubber, and also extended to the entire surface of the tag, to protect the PVC from direct contact with the hot walls of the mould. Alternatively, they may be made of polymeric material with high heat resistance and low conductivity

(polycarbonate, polyamide, polyamide/glass and the like) .

The mould may advantageously have suitable shapes so as to form on the casing appendages, holes, reinforcements or any connection and assembly members with the item to be monitored through RFID technology.