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TECHNICAL FIELD The present invention relates to a process for decorating mosquito-curtains and/or zippers.

More particularly, the present invention relates to a process allowing a mosquito-curtain and/or an automatic zipper used in connection with articles of clothing or leather articles or shoes to be decorated by means of a permanent, coloured pattern.

Moreover, the invention relates to an industrial machine for carrying out said process.

BACKGROUND ART The mosquito-curtains known in the art are generally constituted by a mesh fabric made of a synthetic or metallic material.

Said curtains are generally fastened to frames of different possible shapes, and they are applied as window wings in order to prevent the entrance of insects into a given room and, at the same time, to allow a person being in said room to look outside of the window.

In certain cases a given insecticide is scattered on the curtains in order to enhance their repulsion effect. The mosquito-curtains made of synthetic or metallic material known in the art are normally available in a single, uniformly distributed, colouring (generally in a white colour), which is either obtained by spraying a paint, or by means of a bath in a suitable tank containing the paint, or by means of flexography.

The zippers are also widely known and used in connection with articles of clothing, bags and other different articles; said zippers are constituted by a first

and a second series of small teeth mounted on a support which is generally made of fabric, said teeth being alternately fixed to each other by means of a slider.

Both the teeth and the slider can be made of a metallic or a synthetic material.

As in the case of mosquito-curtains, zippers are normally available either in a single colouring (which covers both the teeth and their respective supports), or in a first colouring for the teeth and a second one for the supports.

However, it is not possible to decorate or to further colour the visible surface of the teeth, of the supports, or of the assembly constituted by the various zipper elements.

DESCRIPTION OF THE INVENTION The present invention aims to provide for a new process allowing mosquito-curtains or zippers to be permanently decorated or coloured, in such a way as to print on the visible surface any desirable colouring or decoration.

This is obtained by means of a process having the features disclosed in the main claims.

The dependent claims describe particularly advantageous forms of embodiment of the process according to the invention.

Furthermore, the invention aims to provide for a machine allowing said colouring or decorating process to be carried out on industrial scale.

This is achieved by means of a machine having the features disclosed in claim 9.

The claims dependent on claim 9 describe advantageous forms of embodiment of said machine.

According to the present invention, the process for decorating and/or for colouring mosquito-curtains or zippers includes a heat transfer on the latter's visible surface of

a sublimatic or physic dye carried by a suitable support which is generally constituted by transfer paper having a sheet or roll conformation.

Said process, which is carried out at predetermined temperatures and for predetermined periods of time, allows the sublimatic or physic dye to be permanently transferred on the material surface.

In this way, it is possible to permanently decorate or colour the surface of the mosquito-curtain or of the zipper, thereby providing the mosquito-curtain or the zipper, or particular portions thereof (such as, for instance, only the teeth or only the supports) , with a predetermined decoration, e.g. the reproduction of a photograph or of a picture, or any other possible drawing or pattern, thereby achieving the scopes of the invention.

ILLUSTRATION OF DRAWINGS Other features and advantages of the invention will become apparent by reading the following description, given as a non-limiting example, with the help of the figures illustrated in the attached drawings, in which: figure 1 shows a schematical side view of an industrial machine for carrying out the process according to the present invention for colouring and/or decorating zippers; and - figure 2 shows a schematical side view of a machine for decorating and/or colouring mosquito-curtains. DESCRIPTION OF A FORM OF EMBODIMENT In figure 1, reference sign 10 generally indicates a machine for industrial use suitable for carrying out a process for decorating and/or colouring zippers according to the present invention.

According to this form of embodiment, machine 10 comprises a supporting framework 11 bearing a pressing unit

12 which is operable by e.g. a jack 13 in order to carry out a vertical movement as indicated by arrow A, and which is provided with a pressing surface which is constituted, for instance, either by a sheet made of an aluminium alloy, or by a layered material having an external covering made of fabric.

A first pair of supports 14, which are rigidly fixed to the uprights 15 of framework 11, bears a first drum 16 on which is wounded a paper band 17 for transfer dyes for sublimation and/or flexible transferization, e.g. a transfer band for sublimatic dyes of the type manufactured by Confalonieri F.lli Di Mario S.p.A., Bergamo, Italy, said band acting as carrier film of a decoration having a predetermined drawing or pattern, realised by means of sublimatic dyes.

The opposite uprights 18 of framework 11 carry a second pair of supports, which bears a second drum 19 on which said band is wounded after having been unwounded from drum 16.

The wounding and unwounding path of band 17 is illustrated in figure 1, and it may be noted that said band slides under the pressing unit 12 which, according to a particularly advantageous form of embodiment of the invention, is internally provided with heating means, e.g. electric resistors. According to the form of embodiment illustrated in figure 1, the pressing unit acts on a working plane which is in this case constituted by a conveyor 20, e.g. a conveyor having an intermittent motion, on which a series of zippers 21 are supported, as coming by preceding working or preparing units.

Conveyor 20 may in this case be provided with a plurality of parallel guiding tracks, in such a way as to allow the colouring process to be simultaneously carried out

on a plurality of zippers placed side by side.

Concerning the specific form of embodiment illustrated m figure 1, the process according to the invention is carried out by unwounding band 17 from drum 16 over a predetermined length, then temporarily arresting conveyor 20 and simultaneously lowering the pressing unit 12 on zippers 21.

The application of the pressing unit for a predetermined period of time (normally for few seconds) on the surface (or at a very short distance therefrom) of zippers 21, and the simultaneous application of heat (the process, according to different instances, is carried out at a temperature comprised between 50°C and 250°C) , cause the dye pigments to be transferred by sublimation from band 17 to the surface of zippers 21.

A process of this kind allows the dye pigments to cross the zipper surface over a thickness of some microns, what gives the material a permanent colouring or, according to different cases, a permanent decoration. Furthermore, since the migration of the dye from its carrier is carried out under application of heat (and not only by applying a given pressure) , it is possible to colour the teeth supporting fabric between each pair of adjacent teeth after the latter have been assembled on the supporting fabric, and this is impossible by means of the colouring processes known in the art.

The form of embodiment illustrated in figure 1 has been provided as an example; it is possible to carry out the zipper movement through means which are different from the heremabove described ones, e.g. by loading the zippers on rolls.

Figure 2 illustrated another form of embodiment of the machine according to the present invention; the machine

elements which have already been described w th reference to figure 1 bear the same reference signs.

In a similar fashion as m the previously described and illustrated case, machine 10' according to figure 2 allows a multicoloured drawing or pattern, which is present on a carrier constituted by a paper band 17' for transfer dyes for sublimation or flexible transferization, to be transferred on a mosquito-curtam 22 which, according to this form of embodiment, is fed starting from a first roller 23 mounted on a support 24 integral to the machine framework 11'; the mosquito-curtain slides on a working plane 20' placed under the pressing unit 12', and it is wound on a drawing frame roller 25 which is mounted on a support 26 integral to the framework 11' of machine 10' . The operation of machine 10' is immediately deducible from the preceding description: the respective rollers 16, 19 for feeding the transfer paper, and 23, 25 for feeding the mosquito-curtam are simultaneously moved by means of a suitable command given by a control electronics (not shown in the figure) , in such a way as the same length of transfer paper 17' and of mosquito-curtam 22 is placed under the pressing unit 12' .

Thereafter, unit 12' is lowered on the working plan (which may be provided, in this case too, with autonomous heating means) and, if necessary, it is pressed on the mosquito-curta 22 in such a way as to carry out the migration process of the dye from band 17' on the yarns or wires forming the curtain mesh.

Then, the rollers are driven again, as controlled by a suitable electronics, the curtain is wound on roller 25 and, simultaneously, a new curtain portion is placed under the pressing unit 12'.

Machine 10' according to figure 2 is illustrated m a

schematical way only for showing the process according to the invention.

In any case, said machine may comprise some further elements in order to enhance carrying out said process. By way of example, machine 10' may be provided with a ventilation and/or drying unit, which is placed downstream of the pressing unit 12', so that the dye is fixed to the curtain and it gets dry before the curtain is wounded on roller 25. Furthermore, machine 10' may be provided with a series of nozzles (not shown) suitable for spraying on the mosquito-curtain a given insecticide after the colouring process; however, according to a preferred form of embodiment, said insecticide is previously mixed to the transfer dye and it is available on the transfer band, in such a way as it migrates on the curtain together with the dye pigments during the operation of the pressing unit.

Machine 10', as previously described, allows the process according to the invention to be carried out in an industrial plant for the continuous manufacture of mosquito- curtains either made of a synthetic or a metallic material, or of fiber glass, or of a composite metallic/synthetic fabric having a higher or lower flexibility according to the weft and/or to the thickness of the curtain yarns or wires; furthermore, in the case of curtains made of a synthetic material, the transfer of the dyes takes place on one or both sides (upper and lower) of the curtain while, in the case of metallic mosquito-curtains, the transfer takes place only on the curtain side which contacts the pressing unit 12' .

The machine according to the invention may be adapted to other working situations which may appear according to different manufacturing requirements.

By way of example, machine 10 or 10' may be provided with means (not shown in the figures) , such as an external structure and a vacuum pump, allowing the dye transfer process to be carried out under vacuum or at a pressure in any case lower than the atmospheric pressure; this is extremely advantageous in what concerns the quality of dye transfer.

The colouring or decoration process according to the present invention provides for some particularly advantageous forms of embodiment which highly improve the quality results m what concerns the dye transfer.

According to a first advantageous form of embodiment, the mosquito-curtains or the zippers include a polyester resin, which highly enhances the process of dye sublimation. in several cases this allows the dye transfer time to be lowered, as well as a deeper penetration of the dye into the material .

From the foregoing it appears that the process according to the mvention allows a mosquito-curtam or a zipper to be coloured or decorated by any dye or pattern.

This implies some advantages which go far beyond the evident aesthetic advantage which is immediately visible at first sight: in fact, the process according to the invention allows a production on industrial scale of either mosquito- curtains or zippers having any basic colouring to be carried out, said curtains or zippers being later coloured or decorated according to personalized particular patterns or drawings, or following to specific requests.

The invention has previously been described with reference to some preferred forms of embodiment.

However, it is clear that the invention includes several different forms of embodiment falling within the terms of technical equivalents.

By way of example, the pressing unit may also be constituted by a unit suitable for applying a given fluid, e.g. air, steam, gas etc. at a given pressure and at a given temperature, on the surface of the material. Furthermore, the process according to the invention may be carried out, according to the requirements, by applying on the mosquito-curtain or on the zipper, through means similar to those which have previously been described, a phisic dye or pattern on transfer paper; in this case the best results may only be achieved by simultaneously applying a given pressure at a given temperature on the material to be decorated.

Moreover, a more effective stabilisation of sublimation dyes on the mosquito-curtains or on the zippers can be achieved by previously spraying on them a polyester transparent paint .