WO2000030868A1

WO2000030868A1 - Method and apparatus for producing a silicone film for industrial decoration of objects

Info

Publication number: WO2000030868A1
Application number: PCT/IB1999/001855
Authority: WO
Inventors: Tito Trevisan
Original assignee: Tito Trevisan
Priority date: 1998-11-20
Filing date: 1999-11-19
Publication date: 2000-06-02
Also published as: AU1070000A

Abstract

A flexible and extendible material for decorating metallic and nonmetallic surfaces which comprises a first sheet or layer of high ultimate elongation material, which is obtained by spreading on a suitable support, and a second sheet or layer, which is obtained spreading on or immersing the first layer in a material having high plastic elongation, is pigmentable, has a low friction coefficient, and is chosen among at least one of the members of the group formed by polyvinyl butyraldehyde, polyvinyl alcohol, polyvinyl acetate, polyurethane, polyethylene and polyamide. A method for obtaining a silicone film for industrial decoration of objects and an apparatus for performing the same.

Description

METHOD AND APPARATUS FOR PRODUCING A SILICONE FILM FOR INDUSTRIAL DECORATION OF OBJECTS

Technical field The present invention relates to a silicone film which to be used as a roll or in sheets in the field of industrial decoration, particularly for finishing metallic and nonmetallic products.

Background art More specifically, the present invention relates to a new use of a material known per se, i.e., a silicone rubber. It is known in the art to produce decorations, e.g. on plastic material coatings of metals, by using sheet materials, such as paper films, polyester films with a metallized coating, on which graphic decorations are printed by rotogravure or flexographic or offset printing, said decorations comprising: ~ sublimative inks, i.e. inks suitable for being transferred from a source support to a surface to be decorated, which acts as a receptor mainly owing to heat application at a suitable temperature; or

~ transfer inks, i.e., inks which are physically transferred from a source support to a workpiece to be decorated due to application of pressure and/or heat. Apparatuses have also been proposed which through membranes or elastic sheets withstanding thermal stresses up to approximately 200°C and negative pressures (down to -60 cm Hg), keep a decorating support faced to receiving workpiece to be decorated.

Industrial decoration with inks through conventional methods has heavy limitations and drawbacks, since the elastic sheet or membrane is not strong enough to ensure production continuity and in any case entails relatively high costs. Moreover, the support means used is predominantly paper or metallized polyester and is not a resilient one so as to be able to follow any deformations to which the membrane is subjected. It is instead necessary to perform very accurate preparation (packing) with consequent high costs both for labor and production which is necessarily quite slow.

Furthermore, as the elastic membrane is opaque it is impossible to check packing while vacuum is applied and its substantial thickness (1-3 mm) prevents proper mating at areas having a small radius of curvature and by being made of a heat insulating material said membrane also slows the heat transient state in reaching the transfer temperature (generally between 150° and 220°C).

Finally, it is impossible to use silicone rubber as a support means for direct ink printing because the same is impermeable to water and to solvents in general.

Summary of the invention The main object of the present invention is to provide a new flexible and resilient material for decorating metallic and nonmetallic surfaces which has good mechanical strength, a low friction coefficient at its face designed to mate with the surface to be decorated, can be printed with the most common water inks without excessively absorbing sublimated inks, and withstands thermal stresses up to 240°C without degenerating.

Another object of the present invention is to provide a new method for decorating metallic and nonmetallic surfaces which makes it possible to obtain high productivity, without causing environment pollution and to reduce production costs of decorated surfaces.

Another object of the present invention is to provide a plant for producing a new flexible and elastic material for decorating surfaces and an apparatus for performing the decoration method according to the invention. Further specific objects of the present invention are:

- the use of a resilient rubber in the form of a decorating film, i.e., a suitable support means for producing by color sublimation transfer and/or physical transfer of an actual decoration coating material, such as an ink, a painting or laquering; « taking advantage of resilient features of rubber films in order to make it possible to decorate a wide range of objects, including objects having a complex configuration and shape with recessed and in relief portions; and

~ providing a film designed to act both as an excellent support means for printing a decorative pattern and as a film for coating a manufactured item. According to another aspect of the present invention there is provided a flexible and extendible material for decorating metallic and nonmetallic surfaces, which comprises a first sheet or layer of high ultimate elongation material which is obtained by spreading on a suitable support, and a second sheet or layer, which is obtained by spreading on or immersing said first layer in a material having high plastic elongation, is pigmentable, has a low friction coefficient, and is chosen among at least one of the members of the group comprising polyvinyl butyraldehyde, polyvinyl alcohol, polyvinyl acetate, polyurethane, polyethylene and polyamide.

Advantageously, said flexible and resilient material comprises a composite element including two sheets or layers.

According to another aspect of the present invention there is provided a method of producing a silicone film, which comprises:

- preparing a suitable paper or polyolefin or metallic support layer;

- optionally applying a suitable release agent to one side of said support layer by using a rotogravure or flexographic machine;

- baking the composite film at a temperature ranging approximately from 150° and 220°C for a time interval of approximately 10 seconds to 10 minutes; and

- cooling the composite baked film in air or by means of air convection. Advantageously, if the support layer is not paper, provisions are made for applying a layer of silicone rubber on the side covered with release agent , so as to obtain a multilayer composite film.

According to another aspect of the present invention there is provided an apparatus for producing a silicone film, which comprises a source of flexible support sheet material, a unit for feeding a silicone rubber to be applied, at least one application station which is arranged to apply a layer of silicone rubber onto said support material fed thereto, and at least one baking oven, which is located downstream of a respective application station and is designed to dry said layer of silicone rubber on said supporting material.

According to another aspect of the present invention there is provided a method of decorating metallic and nonmetallic surfaces, which comprises the steps of: preparing a flexible and extendible sheet or ribbon material having a pigmented and/or coated side; uniformly applying the pigmented and/or coated side of said flexible and extendible material to the surface of any configuration of an object or objects to be decorated, utilizing the extendibility of the material under pressure and/or suction; heating the object or objects in contact with said pigmented or coated material to a temperature ranging approximately from 100° to 230° C thereby causing pigmentation or coating material to transfer from the pigmented or coated material to the surface of the object or objects to be decorated.

Example 1 Production of a composite two-laver film A first layer is preferably obtained by spreading on a suitable low- roughness support, e.g. a paper support, a low-viscosity silicone rubber obtained by putting together together with a 1:10 ratio two components A and B of a liquid silicone rubber, commercially known as Silastic™ 9252/150P, produced and marketed by Dow Corning, USA, and by mixing thoroughly until a uniform mixture is obtained. The layer of silicone rubber thus spread is then baked in an oven at approximately 180°C for two minutes. A dispersion containing polyvinyl butyraldehyde, polyvinyl alcohol and polyvinyl acetate, e.g. that commercially known as Ascott™ and manufactured and marketed by Inteko S.r.l., Italy, is then spread (approximately 20 μm) over the layer thus dried. The layer of Ascott is then dried in an oven at approximately 80°C for about 2 minutes.

Preferably, the two-layer sheet or ribbon material thus formed is subjected to a final stabilization treatment in an oven at approximately 200°C for two minutes. A stable composite two-layer sheet or ribbon material is thus obtained.

An Ascott™ layer besides promoting easy pigmentation (i.e., inking and metallization), has a low friction coefficient, bonds well with silicone rubber, has high ultimate elongation whereby uniformly covering the surface of an object to be decorated on which said material is applied by applying pressure or a suction action and thus adapting on it practically with no friction or grip, i.e. with no stress, even in the case of a convoluted surface including undercut portions and/or grooves or narrow slots, and is resistant up to about 240°C without degenerating or sticking to the item to be decorated. The other (second) layer made of silicone rubber, is instead highly resilient and fully impermeable to water and solvents and has high mechanical strength. Thus it can act, in use, as an effective barrier to the backward leakage of pigments or solvents provided on the Ascott™ layer, as is also further explained hereinafter, its thickness being so small that it can adhere, wrap around or cover even regions having a small radius.

Then the initial paper support is removed by peeling it off and the rubber material can be stored or subjected to a pigmentation or coating treatment, i.e., inking with sublimating ink or with so-called transfer ink or metallization or full or partial coating with a transferable compound, on its first Ascott™ layer, according to any suitable pigmentation method which is well-known per se to a skilled person in the field, in order to obtain a given pattern or decoration.

Once the pigment has been applied, the initial paper support is removed by peeling it off. It is then possible to apply the composite material thus pigmented to one or more objects to be decorated, so that the decorated side of the material is brought into direct contact with the surface of such object or objects. This operation can be performed either by suction applied between the surface of the object or objects to be decorated and the decorated surface of the composite material or by applying pressure to the silicone rubber layer, e.g. by means of a pressurized fluid or a combination of vacuum and pressure, by taking advantage of the extendibility of the two-layer composite material. The object or objects in close contact with the pigmented or coated material are then heated up at a temperature ranging approximately from 110°C to about 250°C in the case of transfer ink and from approximately 120° and to approximately 210°C in the case of sublimating ink, to produce the release or transfer of the pigment or coating from the pigmented or coated layer of the composite material to the surface of the object or objects to be decorated. The pattern or ornament thus applied to the object or objects is of excellent quality and remains permanently fixed to the decorated surface.

Advantageously, the application of pressure and heat to cause the pigment or coating to be transferred can be performed by means of a hot pressurized fluid (liquid or gas) and/or by applying mechanical pressure by means of one or more pads. Example 2

The same procedure as Example 1 is followed, except that the layer of Ascott™ is spread (10-20 μm in thickness) on a suitable support and is separately inked in a sheet or ribbon form, whereas the layer of silicone rubber, instead of being spread onto the layer of Ascott™, is spread onto a suitable support (e.g. a paper support) in order to obtain a separate sheet or ribbon.

In use, the sheet or ribbon of Ascott™ is first applied to the object or objects to be decorated, then the sheet of silicone rubber is placed thereon in the same operating conditions as those described in Example 1, thereby obtaining excellent quality results. Example 3 The same procedure as Example 1 is followed, except that instead of the layer of Ascott™, a thin layer (second layer) of air-permeable material, such as a layer of open-cell synthetic material (sponge) or a thin layer of textile material, e.g. a felt, is applied to a suitable support.

Printing is then performed on the second layer, unless printing was previously carried out.

The resilient film thus obtained as specified above is applied to an object to be pigment or decorated and pressure and/or heat is applied in order to transfer the print to the object with excellent decorative results.

Example 4 The same procedure as Example 3 is followed, except that instead of providing a layer of textile or sponge-like material, the outer side of Ascott™ is rendered spongy by means of any suitable process, thereby achieving excellent decorating results.

According to another aspect of the present invention there is provided an apparatus for producing a flexible and extendible material for decorating surfaces in general, which comprises in sequence: a first spreading station, which is arranged to spread a first material with a thickness between 10 and approximately 10000 μm onto a suitable ribbon support having a preset roughness and/or marking and withstanding at least 180°C; at least one first drying oven for said first spread material, which operates at approximately 40° to approximately 240°C; a second spreading station for spreading with a thickness between 10 and 100 μm onto a second support a second material having relatively high elasticity-elongation; and at least one second drying and/or stabilization oven at a temperature between approximately 100° and approximately 200°C.

According to another aspect of the present invention there is provided an apparatus for decorating one or more objects by means of a material made of two layers or sheets, which comprises: a supporting frame; at least one treatment chamber supported by said supporting frame and comprising two outer shells which can hermetically close one against the other and move mutually apart on command; and a feeder arranged to feed a sheet or ribbon material between each shell and said treatment chamber to delimit an intermediate space for accommodating the object or objects to be decorated. Advantageously, said treatment chamber comprises a frame between the shells arranged to act as a spacer between said shells and the sheet or ribbon fed by said feeder.

Brief description of the drawings Further aspects and advantages of the present invention will become better apparent from the following detailed description of some embodiments thereof, given by way of non-limitative example only with reference to the accompanying drawings, wherein:

Figure 1 is a schematic view of an apparatus for producing a flexible and extendible material according to the present invention;

Figure 2 is a partial sectional view on an enlarged scale, taken along the line II-II of Figure 1;

Figure 3 is a partial sectional view on an enlarged scale, taken along the line III-III of Figure 1; Figure 4 is a partial sectional view on an enlarged scale, taken along the line IV-IV of Figure 1;

Figure 5 is a front elevation view of an apparatus for decorating one or more objects with the method according to the present invention;

Figure 6 is a schematic elevation view of a support for rolls for the apparatus of Figure 5;

Figure 7 is a schematic front elevation view of an oven for accommodating the apparatus of Figure 5;

Figure 8 is a side view with some parts shown in cross-section, of the apparatus of Figure 5 in an open position; Figure 9 is a view similar to Figure 8 but shows the apparatus in its closed position;

Figure 10 is a view on an enlarged scale of a detail of Figure 9; Figure 11 is a schematic view of another embodiment of the decorating apparatus according to the method of the present invention; and Figure 12 is a schematic side elevation view of an apparatus for producing a silicone film according to the present invention.

Ways of carrying out the invention In the accompanying drawings, identical or similar parts or components have been designated by the same reference numerals. With reference first to Figures 1 to 4, it will be noted that a first embodiment of an apparatus for manufacturing a flexible and extendible material according to the present invention comprises a support ribbon or tape 1 made of paper material having a preset roughness, which is unwound from a roll at an unrolling unit, generally designated by the reference numeral 2, and is forwarded along a working path delimited by a plurality of supporting and guiding rollers and multiple treatment stations sequentially distributed along the working path.

More particularly, the ribbon 1 from the unrolling unit 2 is guided to a first spreading station, designated by the reference numeral 3, which comprises a guide cylinder 4 having a relatively large diameter for the ribbon 1 above which a hopper 5 for feeding silicone rubber is located and followed by a doctor 6 arranged at an adjustable distance from the cylinder 4 in order to obtain a uniform and continuous covering layer 7 with a desired thickness, typically approximately 70 μm on the ribbon 1. Downstream of the spreading station 3 a first drying tunnel-type oven 8, e.g. of the infrared type, operating at a temperature of approximately 180°C is provided, through which the ribbon 1 coated with silicone rubber moves for a preset time, e.g. about 2 minutes.

At the outlet of the oven 8, the dried ribbon 1 is guided by a sequence of guide rollers 9 and is then forwarded to a second spreading station 10, at which a uniform and continuous layer 11 of Ascott™, preferably having a thickness of approximately 15 μm, is spread onto the silicone rubber layer 7. The ribbon or tape 1 with the two layers 7 and 11 spread thereon enters then a second drying tunnel-type oven 18, which is kept, for example, at a temperature of approximately 80° C, for a retention time of about two minutes.

If desired, downstream of the drying oven 12 a third stabilization tunnel- type oven 13 can be located, which is kept at a temperature of approximately 200°C and in which the coated ribbon remains for about two minutes.

A guide roller for forwarding the paper ribbon 1 to a takeup unit 15 and a guide support 16 for directing the composite ribbon 17 formed by the layers 7 and 11 to a suitable roll forming unit 18 can be provided at the outlet of oven 12 or 13. According to another embodiment of the above described production apparatus, at the outlet of the drying oven 8 there are two takeup units: one for the support ribbon 1 and the other one for the layer or sheet of silicone rubber 7. At the spreading station 10 and the oven 12, a suitable support ribbon or tape 1 is used to obtain downstream thereof a ribbon or tape 11 of Ascott™ to be used with the sheet 7 in the manner described hereinafter.

Figures 5 to 10 and 11 illustrate two embodiments of an apparatus for decorating one or more objects by using two ribbons 17 or two pairs of ribbons 7 and 11.

The embodiment shown in Figures 5 to 10 comprises a box-like structure 20 which can be opened and closed by being pivoted about one edge thereof and is formed by two lateral shells, i.e., a lower shell 21 and an upper shell 22, and an intermediate peripheral spacer frame 23. The whole assembly is mounted on a carriage 24. The spacer frame 23 is pivoted, at the rear of the structure 20. to the lower shell 21 by means of hinges 25, whereas the upper shell 22 is hinged to the intermediate frame 23 through hinges 26 arranged on the same side as hinges 25. The spacer frame 23 and the shell 22 can be actuated by respective actuators, such as fluid-operated jacks 27 and 28 which have an end hinged to a support 29, which is fixed with respect to the lower shell 21, and two lugs 30 and 31, which extend from the frame 23 and the shell 22, respectively.

At two mutually opposite ends of the structure 20 two supports for one or two pairs of rolls are provided, designated by the reference numerals 37 and 38, respectively. A ribbon or tape 17, or a ribbon 7 and a ribbon 11, are unwound from the rolls 37 and applied on the shell 21, while making sure that the ribbon or layer 11, whose inked or otherwise pigmented side is facing upwards, is arranged above a silicone rubber layer or ribbon. The intermediate frame 23 is lowered onto the ribbon or ribbons thus applied, which cover all the space delimited by the shell 21 and protrude along the entire perimeter of said shell; then the object or objects PF (Figure 9) to be decorated are placed onto the ribbon or layer 11. A second ribbon or tape 17 or a ribbon 7 and a ribbon 11 are applied on the intermediate frame, so that the inked or pigmented layer of the ribbon or layer 11 is facing downwards to contact the object or objects to be decorated. Finally, the upper shell 22 is closed onto the intermediate frame 23. As shown more clearly in Figures 9 and 10, a continuous slot, designated by the reference numerals 40 and 41, respectively, for accommodating a respective sealing gasket 42 and 43, is provided along the upper and lower edges of the intermediate frame 23 and along the upper edge of the shell 21 and the lower edge of the shell 22. The intermediate frame 23 is connected through a duct 45 to a vacuum pump 46 with the interposition of a filter 47, an electric control valve 48, an air inlet valve 49 for opening the structure and a pressure gauge 50. Accordingly, after the structure 20 has been loaded and air-tight closed, as specified above, a desired vacuum is generated inside the frame 23, thereby forcing the sheet material to lean against the surface of the object PF. The structure 20 is then transferred into an oven 51 (Figure 7) to cause the migration or thermal transfer of the pigmentation from layer 7 to the object or objects PF.

At the outlet of the oven 51, the structure 20 is opened, the decorated object PF is removed, the waste of the ribbons 17 or 7-11 is wound onto the rolls 38, and the structure is ready for a subsequent decoration cycle.

The embodiment shown in Figure 11 comprises a supporting structure 55 for two mutually opposite shells 56 and 57 which are movably mounted on the structure 55 so that they can be moved mutually closer until they mate along an equatorial plane and mutually apart, as shown by arrows A. An object or objects PF to be decorated is conveyed by an overhead conveyor, generally designated by the reference numeral 58, and at the shells 56 and 57 it is located in the gap delimited by two ribbons 17 (or by two pairs of ribbons 7 and 11) unwound from respective rolls 37. The shells 56 and 57 are connected through a respective inlet duct 59 and outlet duct 60 to a pressurized hot air feeding system which comprises a blower 61, whose delivery is connected through a duct 62 to a plenum tank 63, which, in turn, supplies, through a duct 64, a heating battery 65, e.g. an electric resistor battery, connected to the duct 59. The intake of the blower 61 is connected to the duct 60 through an electric hot air recirculation valve 66 and an electric ambient air supplying valve 67, said valves being arranged on an intake or return duct 68.

It will be easily noted that with such an apparatus there is no need to resort to vacuum; rather, advantage is taken of the pressure exerted by the air fed into the shells 56 and 57 and the heat released by said air to produce migration or transfer of the pigmentation on the ribbons or layers 7 towards the object or objects PF to be decorated.

In any case, by using a flexible and extendible material according to the present invention having an extremely reduced thickness with a layer or sheet 7 having a good elongation, good mechanical strength and high antifriction properties, i.e., having a low friction coefficient thereby allowing sliding movements on the object to be decorated to adapt itself so as to uniformly cover any possible configuration even at undercut regions of said object. On the other hand, provision of a very thin supporting layer or sheet made of silicone rubber makes it possible to ensure good mechanical stability characteristics and to provide an effective barrier against the back- transfer of the pigments available on the layer or sheet of Ascott 7.

Example 5 A suitable support film was prepared, preferably in roll form, constituted by Mylar™ polyester manufactured by Du Pont de Nemours, USA, and having a thickness of approximately 23 μm. A release agent in a solvent is applied to one side of the Mylar film by using a rotogravure printing machine. However, it is also possible to use a flexographic machine or to perform the application in any other suitable manner. The roll 71 of polyester film 72 thus prepared is then transferred onto an unwinding unit 73 arranged upstream of an apparatus comprising in sequence a spreading unit 74, fed by a pumping unit 75 connected to a mixing unit 76, a baking oven 77, and a takeup unit 78 (Figure 12).

The spreading unit 74 can be of any suitable type. A spreading unit of the type having a rotating doctor blade 79 was used provided with a motor assembly (not shown) having an independently adjustable rotation rate and cooperating with an engraved roller 80 with a screen having 30 to 100 lines per centimeter, depending up on the rate of flow of the product to be spread. A lower pressure roller 81 coated with rubber acts against the engraved roller 80. Above and between the doctor blade 79 and the engraved roller 80, there is located a collection-distribution unit, e.g. a hopper generally designated by the reference numeral 82, fed by a delivery duct 83 of the pump unit 75 with an electric check valve 84 arranged therebetween. The pump unit 75 is connected through a duct 85 to the mixing unit 76, in which parts A and B of a silicone product commercially known as Silastic™ Type 9252/150P (Part A and Part B) manufactured by Dow Corning, USA, is mixed in a 1:10 ratio using vacuum pumps (not shown in the drawing) in order to avoid trapping air in the mixture.

The support film 2 coming from the unwinding unit 73 is forwarded between the pressure roller 81 and the engraved roller 80, which are arranged and actuated in correct synchronization at the gap therebetween, where actual spreading, deposition of material uniformly distributed and applied to the engraved roller 80 by the rotating doctor 79, occurs. In order to adjust the thickness to be spread, one can act on the speed of rotation of the rotating doctor 79 in the same direction as the engraved roller 80 and/or vary in a controlled manner the width of the gap or mutual distance between the doctor 79 and the engraved roller 80.

The silicone product 87 spread onto the support 72 from the spreading unit 74 is then transferred to the oven 77. The oven 77 used is a hot-air forced-convection tunnel-oven. A baking time of 2 seconds at 180°C was maintained.

However, the baking times can vary between 10 seconds and 10 minutes and the internal temperature of the oven can range from 150° and 220°C, depending up on the thickness of the spread silicone product, the nature of the support 71 used and the heat exchange characteristics of the oven.

The baked silicone product leaving the oven 77 is left to cool in ambient air or is cooled by air convection and wound so as to form a roll 89 together with its support at the takeup unit 78.

The roll 89 was ready to be brought to feed a rotogravure machine with one or more colour units using sublimating inks. After inking or coating, the film is ready for use as a decorating film for a large number of metallic and nonmetallic objects, similarly to a paper inked with sublimating inks, but with the great advantage that the inking layer 87, by being made of elastically deformable material, can adapt to decorate even non-flat surfaces, i.e., curved surfaces, with recesses and protrusions having any shape or configuration.

Example 6

The same procedure as in Example 5 was used, except that in order to further enhance printability with sublimating inks, an uninterrupted (solid) coating, constituted by a compound known as Ascott™, manufactured by

Inteko S.r.l., Italy, which is an aqueous dispersion of a plurality of polymers including plasticized polyvinyl butyral, was applied into the silicone film

87. The resulting thickness of the coating after drying in an oven can vary from 2 μm (traces) to 100 μm (preferably about 4 to 20 μm), depending on the mechanical stresses to which the silicone film will be subjected during object decoration.

The composite film can then be forwarded to an inking station to be inked with sublimating inks, e.g. on a rotogravure or flexographic printing machine in one or more colors. At the outlet of the rotogravure machine, the composite film is ready for use in object decoration.

Example 7

Use of a silicone film according to the invention for decorating by sublimation a sheet of PMMA even while the same is being thermoformed a) Preparation From a commercially available sheet of Plexiglas™, on which a protection polyester film glued with any suitable non-adhesive adhesive had been applied, the peelable layer was removed and a compound obtained as specified in Examples 1 and 2 was applied so that its side bearing a sublimating print was facing toward the Plexiglas. The Mylar polyester support is then removed. b) Processing

Thermoformation of the Plexiglas was performed by subjecting the sheet to a thermoforming press so that its side to be decorated was facing away from the mold. A preheating cycle for the sheet is performed by IR (although hot air can be used separately or in combination) in order to achieve a temperature of approximately 180°C to soften the sheet and assist subsequent plastic deformation during molding.

The cycle went on with the mechanical action of the mold and vacuum was applied to obtain a suction action at the concave regions of the mold. As soon as thermoformation was completed, the deformed sheet was cooled by means of jets of water and/or cooling gases.

During preheating and thermoformation of the sheet, temperatures of 160° to 200°C were reached for time intervals ranging from 20 seconds to 15 minutes required to produce sublimating transfer of the ink or inks from the silicone film to the Plexiglas sheet. It was noted that the transfer could continue without smudging of the images or markings even during plastic deformation owing to perfect adhesion of the silicone film to the surface of the sheet being deformed. When the shaped sheet was extracted, it was sufficient to remove the decorating silicone film, thus obtaining a finished decoration of the layer of PMMA (polymethylmethacrylate) with sublimating inks.

This example therefore shows that it is possible to use a silicone film according to the present invention to decorate items made of thermoformable plastic material even during the thermoformation process of the objects.

Example 8 Decoration of a silicone film bv metallization under vacuum A silicone film according to the present invention, obtained according to the Examples 5 or 6 above, was coated by a conventional process for the vacuum vaporization of metals as well as salts and alloys thereof.

The film thus coated was subjected to a cycle of aluminum metallization under vacuum, with preliminary application of an ion discharge processing to ensure better adhesion of aluminum coated on the silicone film. Aluminum coatings with an optical density of more than 1.5 OD were obtained.

Inking with flexographic or rotogravure machines can also be performed with lacquers, e.g. acrylic and/or polyurethane lacquers or paints for physical transfer between 80° and 150°C. This type of inking is particularly suitable for decoration of thermoplastic materials.

The contents of invention patent applications no. VR98A000099 and no. VR99A000030 are included as reference and their priorities are claimed in the present application.

Claims

1. A flexible and extendible material for decorating metallic and nonmetallic surfaces which comprises a first sheet or layer of high ultimate elongation material, which is obtained by spreading on a suitable support, and a second sheet or layer, which is obtained by spreading on or immersing said first layer in a material having high plastic elongation, is pigmentable, has a low friction coefficient, and is chosen among at least one of the members of the group comprising polyvinyl butyraldehyde, polyvinyl alcohol, polyvinyl acetate, polyurethane, polyethylene and polyamide.

2. The material according to claims 1, characterized in that is constitutes a two sheet or layer composite.

3. The material according to claim 1 or 2, characterized in that said first sheet or layer comprises a silicone film with a thickness less than 300 μm.

4. A method of decorating metallic and nonmetallic surfaces, comprising the steps of: preparing a flexible and extendible sheet or tape material according to claim 1 or 2, having a pigmented and/or coated side; uniformly applying the pigmented and/or coated side of said flexible and extendible material to the surface of any configuration of an object or objects to be decorated, utilizing the extendibility of the material under pressure and/or under suction; heating the object or objects in contact with said pigmented or coated material to a temperature ranging approximately from 100° and 230°C, thereby causing pigmentation or coating material to transfer from the pigmented or coated material to the surface of the object or objects to be decorated.

5. An apparatus for producing flexible and extendible material according to any claim 1 to 3, for decorating surfaces in general, which comprises in sequence: a first spreading station, which is arranged to spread a first material with a thickness between approximately 10 and approximately 2000 μm on a suitable ribbon support having a preset roughness and/or marking and withstanding at least 220°C; at least one first drying oven for said first spread material which operates at a temperature lower than 240°C; a second spreading unit for spreading, with a thickness of 10 to 100 μm, onto a second support a second material having relatively high plasticity- elongation; and at least one second drying and/or stabilization oven at a temperature between approximately 100° and approximately 200°C.

6. An apparatus for decorating one or more objects by means of two layer or sheet material according to any claim 1 to 3, comprising: a supporting frame; at least one treatment chamber supported by said supporting frame and comprising two outer shells which can hermetically close one against the other and move mutually apart on command; and a feeding unit for supplying sheet or ribbon material between each shell and said treatment chamber to delimit an intermediate space for accommodating the object or objects to be decorated.

7. The apparatus according to claim 6, characterized in that said treatment chamber comprises a peripheral frame, between the shells so as to act as a spacer between said shells and the sheet or ribbon fed by said feeding unit.

8. The apparatus according to claim 6 or 7, characterized in that it comprises a suction or vacuum generator to be connected to said intermediate space.

9. The apparatus according to claim 6, characterized in that it comprises a hot pressurized fluid source in communication with said treatment chamber outside said intermediate space for accommodating the object or objects to be decorated.

10. The apparatus according to any claim 6 to 9, characterized in that it comprises at least one mechanical pressure-applying pad device for applying pressure in order to cause the sheet or ribbon to adhere to the object to be decorated.

11. A method of producing a silicone film, comprising: — preparing a suitable supporting layer of paper, polyolefin, metal: ~ optionally applying a suitable release agent coating one support layer rubber to obtain a composite multiple layer film; to one side of the support layer by using a rotogravure or flexographic printing machine;

— baking the composite film at a temperature between approximately 150° and 220°C for a time interval between approximately 10 seconds and 10 minutes; and

~ cooling the composite film in air or by means of air convection.

12. The method according to claim 11, characterized in that if said supporting layer is not made of paper material, a layer of silicone rubber is applied to the side coated with release agent, so as to obtain a multilayer composite film.

13. The method according to claim 11 or 12, characterized in that the application of the silicone rubber layer occurs by spreading.

14. The method according to claim 11 or 12, characterized in that the application of the silicone rubber layer occurs by extrusion.

15. The method according to any one of claims 11 to 14, characterized in that said silicone rubber layer is applied with a thickness between 10 and 3000 μm.

16. The method according to any claim 11 to 15, characterized in that it comprises coating on said silicone rubber layer.

17. The method according to claim 16, characterized in that said coating is performed by means of at least one sublimating ink in a rotogravure or flexographic printing machine.

18. The method according to claim 16, characterized in that said coating is performed by means of at least one lacquer or paint.

19. The method according to claim 16, characterized in that said coating is performed by means of at least one physical-transfer ink.

20. The method according to any claim 16 to 19, characterized in that it comprises the application of said coated silicone rubber layer to objects to decorate them.

21. The method according to any one of the preceding claims, characterized in that it comprises the application, on said silicone rubber layer, of a continuous backing comprising an aqueous dispersion of a plurality of plasticized polyvinyl butyral polymers.

22. The method according to claim 21, characterized in that the resulting thickness of the coating after drying in oven can vary from traces to 100 μm.

23. The method according to claim 21 or 22, characterized in that it comprises a step for cooling and/or stabilization after the drying step.

24. The apparatus for producing a silicone rubber film or layer for performing the method according to any one of claims 1 to 13, comprising a source of flexible support sheet material, a unit for feeding silicone rubber to be applied, and at least one application station arranged to apply said silicone rubber to said supporting material fed thereto.

25. The apparatus according to claim 24, characterized in that said feeder unit comprises at least one mixing unit for mixing at least two ingredients of said silicone rubber and at least one unit for pumping the mixed material into mixing unit for feeding said material to an application station.

26. The apparatus according to claim 24 or 25, characterized in that the or each application station comprises a spreading unit.

27. The apparatus according to claim 26. characterized in that the or each spreading unit is of the type with a rotating doctor.

28. The apparatus according to claim 24 or 25, characterized in that the or each application station is an extrusion station.

29. The apparatus according to any one of claims 24 to 28, characterized in that it comprises at least one baking oven which is arranged downstream of a respective application station and is arranged to dry said silicone rubber layer spread by an application station onto said supporting material.

30. The apparatus according to claim 29, characterized in that the or each baking oven is a tunnel-type oven.

31. The apparatus according to claim 29 or 30, characterized in that the or each oven is of the infrared radiation and/or forced hot air convection type.

32. The apparatus according to any one of claims 24 to 31, characterized in that said source of supporting material comprises an unwinding unit for a roll of supporting material.

33. The apparatus according to claim 32, characterized in that it comprises a takeup unit downstream of the or each oven in order to take up said layer of silicone rubber applied to said supporting material.