THERMOFORMABLE PANEL WITH A LEATHER-LIKE SURFACE AND METHOD FOR ITS FABRICATION

Abstract: A thermoformable panel with a surface coating of a type resembling imitation leather comprises at least one supporting layer (1) made of thermoformable plastic, particularly polypropylene, filled with inert organic material, such as wooden chips, granules, powder, or similar, or combinations thereof and at least one coating layer (2, 3, 4) on at least one side of the supporting layer (1), capable to produce a visual and tactile effect of a type resembling that of imitation leather. According to the invention, the coating layer (2, 3, 4) having the aesthetic effect of the imitation leather type is a resin layer, chiefly made of polymers belonging to the same family as those used in the fabrication of the supporting layer (1), particularly polypropylene of the Type Catalloy, i.e. PP-EPR (polypropylene-ethylen-propylen-rubber) mixed with 10 % of homopolymeric polypropylene and the said layer is applied by lamination of a sheet on the supporting layer (1) on fabrication of the latter.

Description: TΗERMOFO MAI.L!: PANEL WITH A LEATHER-LIKE SURFACE AND METHOD FOR ITS FABRICATION The invention relates to a thermoformable panel of the imitation leather type, or similar, comprising at least one supporting layer made of thermoformable plastic, filled with inert organic material, such as wooden chips, granules, powder, or similar, or combinations thereof, and at least one coating layer on at least one side of the supporting layer, capable to produce a visual and tactile effect of the imitation leather type. These types of panels are used in the fabrication of lining, particularly for vehicles, or similar. The said fabrication currently requires the supporting layer be coupled to at least one layer of imitation leather, made of foamed plastic, itself thermoformable, like, for example FVC. Document DE-A-4214389 discloses a panel of the above mentioned type, which comprises three different layers bonded together. A first supporting layer an intermediate layer made of an elastic material like a woven or non woven tissue and a finishing layer made of a thermplastic resin. The finishing layer is provided with embossing particularly of the type imitating the pattern of the surface aspect of the imitation leather. The three layers are made of materials which can at least be melt together and/or having at least one component which is identical or of the same kind. Document DE-A-4423883 discloses a finishing sheet for bulding thermoformable panels which is formed by two layers of thermoformable plastic materials. The two layers may be bonded directly to a supporting layer. The sheet may be provided on the external surface with a pattern like the one resembling leather. Document JP-57031526 teaches how to obtain a thermoformable panel formed by two layers one layer being the supporting layer and the other the coating layer. The two layers are both combined immediately after extrusion. After a short time when the supprting layer material is softened by an organic solvent contained in the coating layer a surface pattern is engraved by a molding utensile. In this case, the panel is not yet bidimensionally or threedimensionalli formed being perfectly plane ecept for the surface pattern od the coating layer. The above mentioned prior art panels and techniques involve some drawbacks, regarding several aspects. A first aspect relates to the fact that the supporting layer is generally made of polyolefin polymers, like, for example, polythene and polypropylene, whereas imitation leather is generally made of FVC. This implies problems in coupling the imitation leather layer to the supporting layer, requiring the use of intermediate layers, such as layers of glueing material, or the presence of a fibrous layer, in the form of fabric, on the fixing side of the layer of imitation leather. Further more, the plastic layer of imitation leather must be foamed, to allow the fabric layer to be fixed. A further aspect, concerning the use of different materials for the supporting and coating layers is the fact that the said known panels are not easily and profitably recyclable, due to the non compatible behaviour of the components of the two layers. As further drawbacks, there are the considerable weight and thickness of the panels with traditional imitation leather lining and the fact that the use of imitation leather considerably complicates the fabrication methods, introducing a phase for mutual coupling of the supporting and coating layers. On this matter, procedures have been developed for the forming of the panel and its substantially simultaneous coupling to the coating layer. The disadvantage of these integrating procedures is that they complicate and slacken the process of simple forming of the panel, the coating layer being necessarily fed separately in the mold, in which it must be retained while overlapping the supporting layer, by means of frames. The forming method encounters a further complication both in the procedure ad in the construction of the mold, whenever the lining has differentiated areas, both for colour and for tactile or softness features. When layers are used of materials being compatible and/or identical and or of the same kind, normally three layers are used. The intermediate layer usually is necessary for giving a soft and elastic sensation to the touch. However, the third intermediate layer is cause of of higher costs, higher weight and higher thickness of the panel . From the point of view of the method for fabricating the panel itself and for forming a finished formed panel, the known techniques teaches to provide the coating layer with the pattern resembling the one of leather during bonding of the layers or shortly after bonding o the layers, in any case befor a shaping of the panel in a mold. Shaping the panel after treatment of the coating layer surface has the great disadvantage, that particulalry in the case of very strong deformations relatively to the plane shape, the pattern resembling the one of the leather is strongly distorted due to strech. The result is a non realistic, non homogeneous appearance of the pattern in the different zones of the shaped panel . The present invention aims at providing a panel of the type described hereinbefore, so that the drawbacks of prior art methods may be avoided, as for the simplification of the processes of fabrication and forming of the finished formed panel, as well as for costs, recyclability, and weight. The invention achieves the above stated purposes by providing a panel of the type described hereinbefore, in which the coating layer having the aesthetic effect of the imitation leather type is made of a resin layer, chiefly made of polymers belonging to the same family as those used in the fabrication of the supporting layer, particularly polyolefin polymers, the said layer being applied by lamination of a sheet on the supporting layer, on fabrication of the latter. The coating layer being made by a polypropylene of the Type Catalloy, particularly PP-EPR (polypropylene- etylen-propylen-rubber) mixed with 10% of homopolymeric polypropylen . The coating layer may be charged with inert materials, partiularly with silicon. The silicon has a granulometry between 0,1 to 0,4 μm. Advantageously, the coating layer is applied on the supporting layer in the form of a sheet, and by lamination, directly on exit of the supporting layer from the extruder. The coating sheet is also obtained through extrusion. The panel so obtained has a coating layer with a remarkable workability as regards the - impression of embossings or ribs, fit to imitate the surface pattern of leather or imitation leather. Obviously, the panel according to the invention may also have differently patterned surface embossings, when no effect of the imitation leather type is desired. Besides the obvious compatibility of the materials used, the coating layer has a softness and a tactile effect quite similar to those of imitation leather lining, without the need of intermediate layers or connecting the supporting and the coating layer or for providinge the desired soft-touch effect. All this may be obtained with a coating layer with thicknesses notably lower than those of traditional imitation leather. Typically, the coating layer has thicknesses between 50 and 3000 μm, preferably between 200 and 600 μm. The panel according to the invention has lower costs, lower weight and a better appearance and touch effect, respecting the minimun thickness requirements of the field. From the point of view of the method for fabricating the panel, it is to be considered that the above mentioned panel allowas very simple and low costs treatment of coatings made of at least two different layers . As the following disclosure will describe in greater detail , the panel according to the invention also lends itself advantageously to the manufacture of panels with differentiated coatings as regards the aesthetic effect, particularly colour and type of embossing, and tactile effect, particularly softness. The composition of the resin chiefly made of polyolefin polymers may advantageously comprise different addition agents, which increase its mechanical and chemical stability, like, for example, alternatively or in combination, an antiscratch additive, and a stabilizer against the effects of the UV rays. Moreover, different colours may be easily obtained for the lining by adding different types of pigments. Whenever the supporting layer has a surface aspect which is meant to be kept in sight, then the resin, and consequently the coating sheet, laminated on the supporting layer may be trasparent or translucent. Furthermore, the panel according to the invention, or rather its coating layer, has a very good behaviour during the shaping of the panel, as it has no bleaching effect . The above advantages are enhanced by the advantages derived from the remarkable thinness of the coating layer required to obtain the aesthetic and tactile effect of the imitation leather type, and consisting in an obvious saving of material , and thus an improved economy and lightness of the panel . The invention also relates to a method for the fabrication of the above described coated panel , comprising a phase for the extrusion of a sheet composed of polyolefin polymers, which is chronologically simultaneous to or separate from a phase for the extrusion of the supporting layer and a phase for the application of the coating sheet on at least one side of the supporting layer on exit of the latter from the extruder, by lamination. Typically, extrusion is executed at temperatures between 100 and 400°C, perferably between 200 and 300°C. The method according to the invention also comprises a phase for the embossing of the coating layer, which is carried out in a subsequent panel shaping phase. The invention also provides other characteristics which form the subject of the dependent claims . The characteristics of the invention and the advantages derived therefrom will appear more clearly from the following description of an embodiment illustrated in the annexed drawings, in which: Fig. 1 is a perspective view of a first embodiment of the panel according to the invention. Fig. 2 shows a variant embodiment for the formation of panels with differentiated coating. Figs. 3 to 5 show a variant of differentiated coating. Fig. 1 shows a panel according to the invention, comprising a supporting layer 1 , made of thermoformable plastic, particularly chiefly made of polyolefin polymers, like, for example, polypropylene filled with wood flour, or similar cellulosic materials. On at least one sidw of the supporting layer 1, a coating layer 2 is applied, which is composed of a sheet chiefly made of polyolefin polymers. Preferably the coating layer is made by a polypropilene type CALLOY, i.e. PP-EPR (polypropilene-etylen-propylen- rubber) mixed with 10% of homopolimeric polypropilene. The resin may contain also a inert charge, particularly like silicon. The silicon have a granulometry of about 0,1 to 0,4 μm. The coating sheet and the supporting layer are both obtained by extrusion and the coated panel is obtained by lamination of the coating sheet on the supporting layer on exit of the latter from the extruder. The panel so obtained is then subjected to the embossing of the coating layer, in order to obtain a surface structure similar to that of leather or of the so-called imitation leather, and eventually of different and any type. Advantageously embossing is executed in a subsequent panel shaping phase, to obtain the finished product, like vehicle lining, or similar. The method for fabricating the panel is very simple, fast and economic, and efficiently avoids all the problems derived from the application of traditional imitation leather coatings. Partiularly the shift of the pattern embosing phase at the same time with shaping the panel in a later shaping phase, allows to lower the manufacturing costs and to obtain better final appearance visually and relatively to the touch effect. Thifa shift of the pattern embossing step has not be possible, in this simple way in the case of the traditional panels having an intermediate soft layer. Indeed, during shaping of the panel in the mold the pressure are so high that the complementary pattern on the mold surface would act with very high forces against the panel, thus causing the collapse of the intermediate layer. Thus the final shaped traditional three layer panel would loose all its soft-touch effect if treated like suggested by the invention.. The thicknesses of the coating layer required to obtain the aesthetic and tactile effects, as well as the softness resembling those of imitation leather are very small, and are included between 50 and 3000 μm, preferably between 200 and 600 μm, thus being smaller of some orders of magnitude than the typical thicknesses of traditional imitation leather lining. The composition of the resin chiefly made of polyolefin polymers may comprise different types of additional agents, like, for example, pigments to provide for different colours, antiscratch additives and/or stabilizers against UN rays. The small thickness of the coating layer allows the method to be used for the manufacture of lining elements which are differentiated both for type of colour, and for embossing pattern and/or for tactile effect and softness. As shown in fig. 2, in order to provide panels coated in a differentiated way, with a coating having one or more areas at leant partially surrounded by a different coating, for example one or more inserts, there may be provided the application on the supporting layer of at least two coating layers 2, 3, extending on the whole surface of the coating layer, the upper layer having some missing zones or apertures 103, possibly obtained by die cutting, through which the underlying coating layer appears. This is possible thanks to the very small thickness required for the coating layer. The upper layer 3, with missing zones 103, coinciding with the zones in which the lining must be differentiated may have very small thicknesses, lower than those of the at least partially continuous underlying layer, for the fact that the softness effect of the lining is substantially provided by the lower coating layer 2. Obviously, the upper coating layer 3 may be provided with more missing zones or apertures 103. There may be provided in a very simple, fast and economic way, more areas of differentiated coating, different from each other, by overlapping more coating layers, each having missing zones or apertures 103, which may be either coincident with each other, when the lowest coating layer is to appear superficially, or staggered with respect to each other, when the directly underlying layer is to appear superficially. The missing zones, or apertures 103, may also intersect, or overlap partially, thus allowing for matchingc that have been hardly reachable up to this moment, unless at very high costs. The single coating layers are applied following the method described hereinbefore, i.e. they are extruded and then laminated on the supporting layer, one on top of another. The pattern of the differentiated coating may reach considerable levels of complexity, not involving particular additional difficulties or costs, apart from a different configuration of the cutting die tools. Thus, for example, with the panel and method according to the invention there may be provided, at very low costs and with small technological efforts, differentiated lining, in which the differentiated areas are very small and in great numbers. As shown in figs. 3 to 5, not only is it possible to provide differentiated lining in which the coating areas are surronded by a coating of a different type, but it may be also provided differentiated coating areas, in which the two types of coating are delimited by a continuous line. In this way, the supporting layer 2 may be laminated at the same time as the two coating sheets 2, 4, which are next to each other with respect to the direction of their transfer. Advantageously, it is also possible to overlap to a small extent the coating sheets 2, 4, although this is not critical to obtain a clean junction line which, in the panel shaping phase, is defined by a groove along the borderline of the two different coatings, the said groove being so deep as to contain and conceal the borderline between the two coatings . Obvoiusly, this procedure may be extended to provide a coating layer composed of a ' plurality of different strips. Moreover, the procedure indicated in figs. 3 to 5 may be obviously combined with that according to fig. 2, so that, for example, the lower coating layer may be formed by at least two strips with different aesthetic and tactile or softness effects, onto which at least one upper layer is laminated, with at least one missing zone, obtained by die cutting, which extends at least partially on all the strips of the underlying layer, or, alternatively or in combination, with more missing zones which extend simultaneously in coincidence with a single strip or at least a portion of the strips. In combination with the above described different procedures and variants, there may be provided coloured and nontransparent coating layers, or even coating layers which are transparent or translucent. The advantages derived from the panel according to the invention and from the method for its fabrication are self-evident. The current trend for manufacturing differentiated lining always involves applying and fixing the differentiated coating layer on the supporting layer substantially while shaping the panel, which implies remarkable complications both for the construction of molds and for the preparation of the lining. As a rule, the latter is to be prepared previously, by joining together the different coating parts, and by introducing them into the mold, while overlapping the supporting layer and being retained in a frame. Fur her more, in the panel shaping phase, there must be provided means for retaining in position the coating layer, in at least some of its portions, such as the junction lines or the differentiated areas, before the mold is completely closed, such as dandy rolls, or separate operation of some portions of the mold and countermold. Therefore, these technical notes have considerable restrictions as regards the production of complex patterns, with a great number of differentiated coating areas, which can also have irregular shapes and very small extensions. The panel according to the invention may be also easily used for the fabrication of shaped lining panels, in which the outer coating of the panel comprises areas with an aesthetic aspect and a tactile effect of the imitation leather type and other areas coated with fabric or other material . Even in this case, the use of the panel according to the invention allows for easier, faster and cheaper fabricating operations. The current procedure is in fact quite similar to the above disclosure regarding the panels with differentiated coating, as for colour or other aspects of the same material, since a portion of the coating is replaced by fabric or similar. Thanks to the panel according to the invention, in its simplest form or in the one providing for differentiated coating, it is sufficient to apply, in the forming phase, the piece of fabric or coating of another material, in the predetennined position, providing for coupling of that fabric part alone, while lorming the panel. Then, a suitable groove along the perimeter of the coating made of fabric or another different material, provides clean junction lines, when the depth of said groove is such that the edges of the coating made of different material, like fabric or similar, may be housed inside it. Naturally, the invention is not limited to what has been described and illustrated hereinbefore, but may be greatly varied and modified, especially as regards construction, without departure from the scope disclosed above and claimed below.

Claims: CLAIMS 1. Thermoformable panel with a surface coating of a type resembling imitation leather, or similar, comprising at least one supporting layer (1) made of 5 thermoformable plastic particularly of polypropilene, filled with inert organic material, such as wooden chips, granules, powder, or similar, or combinations thereof, and one coating layer (2, 3, 4) on at least one side of the supporting layer (1) , capable to 10 produce a visual and tactile effect of a type resembling that of imitation leather, characterized in that the coating layer (2, 3, 4) having the aesthetic effect of the imitation leather type is a resin layer, chiefly made of polymers belonging to the same family 15 as those used in the fabrication of the supporting layer (1) , particulalry of polypropylene of the type Catalloy, i. e. PP-EPR (polypropylen-etylen-propylenb rubber) mixed with 10% of homopolymeric polypropilene, the said coating layer being applied by lamination of a 20 sheet on the supporting layer (1) on fabrication of the latter. 2. Panel as claimed in claim 1 , characterized in that the coating layer (2) has a thickness between 50 and 3000 μm, preferably between 200 and 600 μm. 25 3. Panel as claimed in claims 1 and 2, characterised in that the thermoplastic resin aout of which is made the coating layer is charged with silicon granuates having a granulometry of about 0,1 to 0,4 μm. 4. Panel as claimed in one or more of the -30 preceding claims, characterized in that the coating layer is obtained by extrusion of a sheet. 5. Panel as claimed in one or more of the preceding claims, characterized in that the resin includes an additional agent, made of an a tiscratch substance. 6. Panel as claimed in one or more of the preceding claims, characterized in that the resin includes an additional agent, made of a stabilizer against UV rays . 7. Panel as claimed in one or more of the preceding claims, characterized in that the resin includes at least a colour pigment. 8. Panel as claimed in one or more of the preceding claims, characterized in that the coating layer (2, 3, 4), i.e. the laminated coating sheet, and the resin for making it may be transparent, translucent, or nontransparent and, in combination with one of the two possibilities, eventually coloured or not. 9. Panel as claimed in one or more of the preceding claims, characterized in that the coating sheet is applied on the supporting -layer (1) , directly downstream the extruder producing the latter, through lamination. 10. Panel as claimed in one or more of the preceding claims, characterized in that it has at least one lower coating layer (2) , directly next to the supporting layer (1) and at least one coating layer (3) , ovelapping the lower coating layer (2) and provided with apertures or missing zones, surrounded at least partially by a lateral delimitation edge, the said zones or apertures (103) enabling the lower coating layer (2) to appear on the outside. 11. Panel as claimed in claim 9, characterized in that it has a plurality of overlapped coating layers (2, 3), the lowest one (2) being directly next to the supporting layer (1) and the other outer layers (3) being provided of at least one or more missing zones or apertures (103) , at least some of the said missing zones or apertures (103) of the single outer coating layers being arranged in such a way as to overlap or intersect at least partially to each other, and alternatively or in combination at least some of the said missing zones or apertures being arranged so as to avoid overlapping or intersection, so that at least part of the lower coating layer (2) , in contact with the supporting layer (1) , is made to appear on the exposed side of the panel, as well as, alternatively or in combination, at least part of the intermediate coating layers directly underlying an overlapped coating layer. 12. Panel as claimed in one or more of the preceding claims, characterized in that at least one coating layer (2) is composed of at least two adjacent parts, one next to the other (2, 4), which may overlap at the borderline, be flush to each other or at a short distance, and that they are applied by lamination of the supporting layer (1) with at least two adjacent coating sheets . 13. Panel as claimed in one or more of the preceding claims, characterized in that the borderlines of the different coating layers are provided in coincidence with means for the formation of grooves in the panel on shaping of the latter. 1 . Panel as claimed in one or more of the preceding claims, characterized in that it provides the combination of coating layers as claimed in claim 12, with at least one coating layer (3) provided with at least one aperture or missing zone (103) , spanning the different coating parts (2, 4) or, alternatively or in combination, with at least one aperture or missing zone (103) coinciding with at least one of the different adjacent coating parts (2, 4) . 15. Panel as claimed in one or more of the preceding claims, characterized in that the single coating layers are applied either by lamination on the supporting layer (1) and on the underlying coating layer (2, 4) of an additional coating sheet which has been previously die cut, or by simultaneous lamination of more adjacent coating sheets on the supporting layer (1). 16. Panel as claimed in one or more of the preceding claims, characterized in that the single coating layers (2, 3, 4) are different as regards colour, and/or pattern of the surface structure, and/or softness, and/or thickness. 17. Panel as claimed in one or more of the preceding claims, characterized in that the coating layer (2) being in direct contact with the supporting layer (1) generally has the higher thickness, whereas the upper layers are thinner. 18. Panel as claimed in one or more of the preceding claims, characterized in that it has at least one supporting layer (1) , at least one coating layer (2, 3, 4), of the type having an aesthetic aspect of the leather or imitation leather type, and at least on one portion thereof, a coating layer of a different material, for example fabric, or similar, whose borderlines are preferably housed, or meant to be housed on forming, inside grooves. 19. Panel as claimed in one or more of the preceding claims, characterized in that the coating layer or layers (2, 3, 4) or the outer portions thereof are provided with embossing, particularly of the type imitating the pattern of the surface aspect of the imitation leather. 20. Method for the fabrication of a thermoformable panel with a surface coating of a type resembling imitation leather, or similar, as claimed in one or more of the preceding claims, characterized in that it comprises a phase for the extrusion of a sheet composed of polyolefin polymers, wwich is chronologically simultaneous to or separate from a phase for the extrusion of the supporting layer and at least one phase for the application of the coating sheet on at least one side of the supporting layer on exit of the latter from the extruder, by lamination, while a pattern resembling the one of the leather is embossed by molding in a further step carried together with the shaping of the panel to its final bidimensional or three dimensional shape. 21. Method as claimed in claim 22, characterized in that extrusion is typically executed at temperatures between 100 and 400°C, preferably between 200 and 300°C. 22. Method as claimed in one or more of the preceding claims, for providing panels with differentiated coatings, characterized in that it comprises a separate, simultaneous or sequential extrusion of more coating sheets, with different features, regarding colour and/or tactile effect and/or thickness, and the application in an adjacent position of the said sheets, by lamination on a supporting layer (1) on exit from the extruder reserved thereto, in such a way that the coating sheets may be flush to each other, or at a short distance, or slightly overlapping along the lateral edges . 23. Method as claimed in one or more of the preceding claims, characterized in that it comprises a phase for the separate and simultaneous or sequential extrusion of at least two or more coating sheets, differing for their aesthetic aspect, for colour and/or tactile effect, and/or thickness, and their sequential application by lamination, one directly on the supporting layer (1) and the following on the sheet previously applied, whereas the outer sheet is previously subjected to removal of a zone at least partially surrounded by an edge, by die cutting, notching, or similar. 2 . Method as claimed in one or more of the preceding claims, characterized in that the sheets are subjected to embossing to provide surface patterns which may be different from or identical to each other, before lamination on the supporting layer (1) , while lamination, or in the following forming phase. 25. Method as claimed in one or more of the preceding claims, characterized in that the borderlines between the coating layers (2, 3, 4) are provided in coincidence with grooves being so deep as to conceal them inside, the said grooves being made during the panel shaping phase. 26. Method as claimed in one or more of the preceding claims, characterized in that, after lamination, and during the panel shaping phase, one or more additional coating layers are applied, with a resctricted extension with respect to that of the panel, and of a different material with respect to that of the coating layer or layers (2 , 3, 4) , pre erably at the same time as the panel shaping, and the peripheral edges of the said additional coating element or elements being concealed inside grooves coi-.ciding therewith and being made while shaping the panel. 27. Method as claimed in one or more of the preceding claims, in which the resin for making the coating layer or layers (2, 3, 4) and the said layer or layers themselves may be transparent, translucent or nontransparent and, in both cases, coloured or not. 28. Method for manufactuirng a thermoformed panel with a surface coating of a type resembling imitation leather, obtained by shaping a panel according to claims 1 to 19 the said panel being manufactured according the method of one or more of the preceding claims 20 to 27, characterized in that it comprises the step of providing the coating layer made of one layer or of two or more adiacent coating layers with an emgraved pattern particularly with an engraved pattern resembling the one of leather which is carried out at the same time while shaping the plane panel according to one or more of the preceding claims 1 to 19, the surface of the mold coming in contact with the coating layer being proided with a structure complementary to the one of the patter to be embossed in the coating layer . 29. Method according to claim 28, characterized in that while shaping a panel having at least two different adiacent coating layers, the said coating layers are provided at the same time with different embossed or engraved patterns, being the surface of the shaping mold coming in contact with the said coating layers provided with different surface structures corresponding to the different patterns and located in the different zones of the surface of the mold coincident with the different adiacent coating layers.

Inventors: COLATARCI MARCO FRANCESCO, ODINO ADRIANO, COLATARCI, MARCO, FRANCESCO, ODINO, ADRIANO
Applicants: GOR APPLIC SPECIALI SRL, G.O.R. APPLICAZIONI SPECIALI S.P.A.
Application year: 1997
Main classification: B29D9
IPC codes: B32B27, B32B37, B32B38, B44C5, B44F9