Patent Publication Number: US-2005142338-A1

Title: Method and apparatus for producing decorating means suitable for decorating objects, and relative decorating means

Description:
The invention concerns a method and an apparatus for producing decorating means suitable for decorating objects, particularly made of transparent material, such as glass or plastic material, and the relative decorating means;  
      U.S. Pat. No. 3,868,286 discloses a process for producing a polyvinyl butyral (PVB) composite interlayer for laminated safety glass. According to said process, a first transparent PVB sheet is decorated on one side with a set design in a printing station, and is then laminated with a second transparent PVB sheet. A composite layer is thereby obtained that is suitable for being placed between two glass plates to obtain decorated safety glass, e.g. a windscreen for vehicles having a top coloured band suitable for preventing the sun&#39;s rays from dazzling the driver.  
      The decorated composite layer can be placed between the glass plates immediately after being produced, or can be wound onto a reel and stored until it is sent to a glassworks.  
      One defect of the process disclosed in U.S. Pat. No. 3,868,286 is due to the difficulty of decorating PVB sheets because of the rather soft, lined and sticky nature of said material. Rotary printing techniques such as flexographic printing and gravure printing provide rather unsatisfactory results when they are used for printing on PVB sheets because the PVB tends to stick to the print rollers and the precision of the decoration is adversely affected.  
      This defect, which may not be particularly noticeable if monochrome bands are printed for the windscreen of motor vehicles, becomes dramatically important if more complicated patterns have to be obtained, said patterns being made up of a large number of colours and having relatively complex contours. A further defect of the process disclosed in U.S. Pat. No. 3,868,286 is due to the fact that PVB is a material with relatively high adhesive power. For this reason, when an interlayer of the type disclosed in U.S. Pat. No. 3,868,286 is wound onto reels wherein a sheet of PVB is in direct contact with an underneath sheet of the same material, the two sheets in contact often stick together, thereby making it difficult to unwind the decorated composite layer from the reel. During unwinding the composite layer may suffer lacerations or tears that impair the quality of the final decorated glass.  
      Yet another further defect of the prior art described above is that the decorated composite layer can easily be damaged during handling, inasmuch as it may be contaminated by powder or other impurities or be scratched by objects with which it may come into contact. The damaged composite layer can obviously not be used to decorate the glass unless a low-quality final decoration is accepted.  
      U.S. Pat. No. 4,173,672 discloses a process for producing decorated safety glass, wherein a coloured impression is transferred from a temporary cellulosic support sheet to a PVB adhesive plastic film spread on a first lamina of glass. This transferring is achieved by means of heat and pressure. The temporary cellulosic support is removed when the coloured impression has been transferred from the cellulosic layer to the PVB and a second lamina of glass is placed over the PVB decorated film in direct contact with it. The two glass laminas and the interposed decorated film are then subject to heat and pressure until the colouring material gets impregnated into the PVB semi-fluid film so as to make this film transparent.  
      According to U.S. Pat. No. 4,173,672, it is necessary to transfer the coloured impression from the temporary cellulosic support to the PVB film when the latter is already placed onto the first lamina glass, because it is very difficult to work on the PVB film due to its adhesive consistency and to its great plasticity.  
      However, the process disclosed in U.S. Pat. No. 4,173,672 requires a long time to be carried out, since two heating and pressing steps are required in order firstly to associate the coloured impression to the PVB and then to put the two glass laminas together.  
      Moreover, the safety glass manufacturer has to keep in his premises all the necessary materials for transferring the coloured impression from the temporary cellulosic support to the PVB film, which requires large warehouses and can cause troubles when the exhausted cellulosic support has to be disposed of.  
      U.S. Pat. No. 5,019,440 discloses a process for producing a decorative glass or plastic plate, comprising spraying onto the glass plate a mixture containing a curing agent, curing said mixture so as to obtain a cured layer, and transferring onto the cured layer a printing image formed on a transfer sheet. A coating layer is then applied onto the transferred image.  
      One aim of the invention is to improve the methods and apparatuses for producing decorating means suitable for decorating objects, particularly in transparent material, such as glass, and the relative decorating means.  
      A further aim of the invention is to enable decorated objects to be obtained that have great print precision.  
      A further aim of the invention is to supply decorating means that cannot be easily damaged, even if it is used in environments that contain dust or impurities or if is handled ungently.  
      Yet another aim of the invention is to prevent the decorating means from sticking together when it is wound onto reels or is placed in contact with one another.  
      Another aim of the invention is to simplify the systems for decorating glass and other transparent materials.  
      According to a first aspect of the invention, a method is provided, comprising feeding first layer means towards a decorating zone, decorating said first layer means, and coupling said first layer means with second layer means so as to obtain flexible decorating means, said decorating comprising transferring onto said first layer means a decorative pattern from support means that initially supports said decorative pattern.  
      According to a second aspect of the invention, an apparatus is provided, comprising first feed means arranged for feeding first layer means towards a decorating zone, and coupling means arranged for coupling said first layer means with second layer means so as to obtain flexible decorating means, said decorating zone being provided with transfer means that is so configured as to transfer a decorative pattern onto said first layer means from support means on which said decorative pattern is initially supported.  
      Owing to these two aspects of the invention, it is possible to obtain decorating means provided with decorations printed with a high degree of print resolution. Transfer print technology enables even complicated patterns to be printed with significant precision on the decorating means, which patterns may comprise a large number of different colours. This advantage is particularly apparent when the material of the first layer means has a relatively soft and adhesive consistency, and cannot be decorated with good results using direct print techniques such as rotary printing.  
      The decorating means thereby obtained is furthermore provided with excellent long-term stability properties even when it is exposed to atmospheric agents and direct sunlight. In fact, the transfer printing technology enables inks containing light-resistant pigments to be used, which allows the brightness and intensity of colour to be maintained even several years after installation of the decorated object.  
      The flexible decorating means produced with the process or the apparatus disclosed above may be used to decorate transparent materials, such as glass or plastic plates. The transparent materials manufacturer can purchase the flexible decorating means from a producer thereof and simply associate said flexible decorating means with the glass or plastic plates to be decorated. Thus, the transparent materials manufacturer does not need to carry out any decorating step on sheets that are intended to be interposed between plastic or glass plates. According to a third aspect of the invention, flexible decorating means is provided, comprising base layer means bearing a decorative pattern, characterised in that, said base layer means is associated with protection means that serves to prevent said base layer means from sticking to adjacent materials.  
      The protection means allows the flexible decorating means to be wound on a reel, since the protection means prevents portions of the base layer means from sticking to adjacent portions of said base layer means already wound on the reel. It is therefore, possible to store the flexible decorating means and to use it to decorate glass or other transparent material after a certain period of time. The processes for producing transparent decorated material are therefore greatly simplified, since the manufacturer merely needs to couple the ready-to-use flexible decorating means to glass or plastic plates.  
      Furthermore, the protection means also prevents the decorating means from being damaged in the event of contact with contaminating substances, or in the case of its being subjected to abrasive action. 
    
    
      In order that the invention may be clearly and completely disclosed, reference will now be made, by way of examples that do not limit the scope of the invention to the accompanying. drawings, wherein:  
       FIG. 1  is a diagrammatic frontal view of an apparatus for producing decorating means suitable for decorating objects;  
       FIG. 2  is an enlarged and interrupted diagrammatic cross-section of decorating means suitable for decorating objects;  
       FIG. 3  is an enlarged and interrupted cross-section of an alternative embodiment of the decorating means of  FIG. 2 ;  
       FIG. 4  is a diagrammatic frontal view of an alternative embodiment of the apparatus of  FIG. 1 ;  
       FIG. 5  is an enlarged and interrupted diagrammatic cross-section of a further alternative embodiment of the decorating means of  FIG. 2 ;  
       FIG. 6  is a diagrammatic frontal view of an apparatus for producing the decorating means of  FIG. 5 . 
    
    
       FIG. 1  shows an apparatus  1  for producing decorating means suitable for decorating objects, said objects being preferably made of a transparent material such as glass or plastic material. The apparatus  1  comprises first feed means  2  suitable for feeding a first base layer  3 , for example in the form of a sheet, towards a decorating zone  4 . The first feed means  2  is provided with a device that is not shown for supporting a first reel  5 , on which the first base layer  3  is initially wound, and for unwinding said first base layer  3  from the first reel  5 .  
      In the decorating zone  4 , the first base layer  3  contacts a support  6 , for example in the form of a sheet, bearing a decorative pattern  7  on one side and initially wound on a further reel  8 . The support  6  may be a film made of polypropylene, or of any other plastic material from which the decorative pattern  1  is easily detached by temperature and/or pressure. To facilitate detachment, appropriate paints can also be applied to the support  6  to facilitate its release.  
      The decorative pattern  7 , was previously printed onto the support  6  by means of any known printing technique, for example gravure printing, flexographic printing, offset printing or any other type of printing. To create the decorative pattern  7  an arbitrary number of colours was used and inks were employed containing light-resistant pigments that can maintain their colour intensity even after prolonged exposure to atmospheric agents and to the sun in particular. It is in particular possible to use inorganic pigments to obtain the colours white and black, or macromolecules of organic origin to obtain the remaining colours.  
      The decorative pattern  7  is transferred to the first base layer  3  in the decorating zone  4  by means of transfer means comprising a pair of pressure rollers  9 , the distance of which from each other may be adjusted as indicated by the arrows F by known adjusting means that is not shown here. One or both the pressure rollers  9  may be advantageously heated, so that the decorative pattern  7  can be easily transferred from the support  6  to the first base layer  3 . Experimental tests have shown that particularly good results can be obtained by cladding one or both the pressure rollers  9  with a layer of hard or silicon rubber.  
      After the decorative pattern  7  has been transferred onto the first base layer  3  through the combined action of heat and pressure, the exhausted support  6  is wound onto an exhausted reel  10 , which may be disposed of in compliance with current regulations or be reused as packing material. The first base layer  3  with the decorative pattern  7  that was previously transferred onto it is then coupled with a second base layer  11 , for example in the form of a sheet, which is applied onto the decorative pattern  7  from the side opposite the first base layer  3 .  
      The second base layer  11  is fed by second feed means  13 , comprising a further device that is not shown for supporting a second reel  12 , onto which the second base layer  11  is initially wound. The second feed means  13  further comprises means that is not shown for unwinding the second base layer  11  from the second reel  12 . The second base layer  11  is coupled with the first base layer  3 , provided with the decorative pattern  7 , by means of coupling means comprising further pressure means, for example a pair of further rollers  14 . The mutual distance between the further rollers  14  may be adjusted as indicated by the arrows F 1  by known adjusting means that is not shown here.  
      One or both the further rollers  14  may be heated in such a way that the second base layer  11  more easily joins the first base layer  3 . Like the pressure rollers  9 , the further rollers  14  may also be clad with hard or silicon rubber.  
      At the outlet of the further rollers  14 , flexible decorating means is thus obtained that comprises a composite layer  15  that has the structure disclosed in  FIG. 2 . The composite layer  15  is provided with a decorative pattern  7  placed between a first base layer  3  and a second base layer  11 .  
      The composite layer  15  may be used to decorate, for example, glass plates. In particular, the composite layer  15  may be placed between two glass plates and used to mutually connect said glass plates according to the known techniques for constructing layered glass.  
      Both the first base layer  3  and the second base layer  11  can be made of polyvinyl butyral, a material that has good adhesive properties and, when placed between the glass plates at suitable temperature and pressure conditions, softens and acts as a glue that ensures good fixing between said plates. Unlike direct printing techniques such as flexographic printing or gravure printing, transfer printing enables high-quality decorations to be achieved even on polyvinyl butyral because the support  6 , which is made from a material that is different from polyvinyl butyral, may easily be printed with high resolution and images that have well defined contours and are subsequently transferred to the polyvinyl butyral with no loss of quality.  
      In an alternative embodiment, disclosed in  FIG. 4 , the apparatus  1  is provided with first associating means  16 , comprising a pair of cylinders  17 , suitable for associating the first base layer  3  unwound from the first reel  5  with a first protection layer  18  initially wound onto a start reel  19 . The cylinders  17  can apply pressure and/or a temperature that will make the first protection layer  18  stick to the first base layer  3 . The latter is then decorated on the side that is not in contact with the first protection layer  18  in the manner previously disclosed.  
      The apparatus  1  further comprises second associating means  20  provided, with two further cylinders  21 , that are similar to the cylinders  17  and are suitable for coupling the second base layer  11  with a second protection layer  22  unwound from a further start reel  23 .  
      The assembly comprising the second base layer  11  and the second protection layer  22  is subsequently coupled, by means of the further rollers  14 , to the first base layer  3  that has been previously decorated and associated with the first protection layer  18 .  
      The structure of the resulting composite layer  15 ′ is disclosed in detail in  FIG. 3 .  
      The material of the first protection layer  18  and of the second protection layer  22  may be polypropylene or polyethylene. Any protective film may be used, but it is preferable to use a material with non-adherent properties, particularly in cases wherein the composite layer is not immediately inserted between the glass plates to be decorated, but is stored, for example in the form of a reel, and is subsequently sent to a manufacturer of objects in glass or transparent material.  
      If the layers of polyvinyl butyral are wound onto a reel without protection layers, said layers tend to stick together and thus make it difficult to unwind the composite layer from the reel when the glass has to be decorated and make breaks or lacerations in said layers more likely.  
      The adhesive force between the first protection layer  18  and the first base layer  3 , and between the second protection layer  22  and the second base layer  11  respectively should be sufficiently low to enable the protection layers to be easily removed from the base layers when the composite layer is used before it is inserted between the glass plates.  
      It is also possible to simply superimpose the protection to layers on the composite layers without creating any reciprocal link.  
      In an alternative embodiment, similar to the one disclosed in  FIG. 1 , the materials wound onto the first reel  5  and onto the second reel  12  may comprise base layers already coupled with the respective protection layers. Thus, an apparatus like the one in  FIG. 1  enables a composite layer to be obtained that has the structure disclosed in  FIG. 3 .  
      Instead of the polyvinyl butyral other suitable materials can be used, in particular polyurethane (PU), or ethylene vinyl acetate (EVA).  
       FIG. 6  shows a further embodiment of the apparatus  1 , which allows a composite layer  15  having the structure shown in  
       FIG. 5  to be obtained.  
      According to the apparatus of  FIG. 6 , the first base layer  3  is unwound from the first reel  5  and conveyed towards the decorating zone  4 . Here the first base layer  3  meets the support  6  unwound from the further reel  8  and bearing the decorative pattern  7 . The pressure rollers  9  press the support  6  against the first base layer  3  and heat is applied so that the decorative pattern  7  is transferred from the support  6  to the first base layer  3 , for example by sublimation.  
      Instead of rewinding the exhaust support onto the exhaust reel as provided in the embodiment of  FIG. 1 , the first base layer  3  bearing the decorative pattern  7  and the support  6  are conveyed towards an exit region of the apparatus  1  and are wound onto a final reel  24 .  
      The pressure rollers  9  act therefore both as a transfer means which allows the decorative pattern  7  to be transferred onto the first base layer  3  from the support  6  and as a coupling means which couples the first base layer  3  to the support  6 . The support  6  coupled to the first base layer  3  works as a protection layer which prevents portions of the first base layer  3  from sticking to underlying portions of the same first base layer  3  when wound on the final reel  24 . It is therefore possible to unwind the intermediate layer  15  from the final reel  24  without damaging the first base layer  3  and the decorative pattern  7  applied thereto.  
      The support  6  furthermore protects the decorative pattern from dust and scratches thus allowing a high quality decorated glass to be obtained.  
      During the decorated glass production process, the intermediate layer  15  is unwound from the final reel  24 , the support  6  is, separated from the first base layer  3  and the latter is placed onto a first glass plate. A second glass plate is then positioned onto the decorated first base layer, and the two glass plates are subject to heat and pressure to obtain a single laminated glass. If the manufacturer so desires, he may also couple a second PVB layer to the decorated first base layer placed onto the first glass plate. It is observed that the embodiment disclosed in  FIG. 6  is particularly simple and allows savings to be achieved in the costs of the protection material, since the exhaust support is also used as a protection means.