The present invention relates to a sheet with three-dimensional pattern provided with three- dimensional projecting structures and to a method for producing it .

The terms sheet with three-dimensional pattern means a part that essentially has two dimensions and therefore can result from the continuous deformation of a single plane part , having a thickness smaller than its width or length but which includes several appendages having a projecting or recessed three- dimensional structure .

A three-dimensional structure can be a recessed one and can be a recess made within the sheet during the molding allowing any elements to be introduced into the sheet .

The expression three-dimensional projecting structure is understood to mean any appendage or element desired to be integral with said sheet . Typically, these are stiffening ribs or fastening systems , moulded as one piece with the sheet , or overthicknesses intended to reduce the moulding pressure .

Said sheets made of thermoplastic material can be used for the interior lining of motor vehicles or for manufacturing apparatuses of everyday use due to the fact that they can provide low manufacturing costs, a light weight and can be easily shaped.

The patent EP 585799 describes a multi- layer sheet composed of a core supporting layer coated by a skin coat, which is provided, on the side opposite to the coat, with a plurality of projections made of the same material as the supporting layer which projections are provided for reinforcing purposes or allow the shaped product to be fastened or attached to other parts or elements .

Ά method for producing the sheets is the moulding of a molten material which is injected into a mould.

In the plastics injection moulding process, plastic is heated and mixed in a feed screw and stored in an accumulator. When the latter is full, its content is injected into a temperature-conditioned closed mould where then the material is cooled. The injection takes place through passages provided in the thickness of the mould.

When the material has reached a sufficiently low temperature to have a suitable mechanical strength, the mould is opened and the part ejected. However, in particular when the structured sheets are thin, the injection of molten material requires high pressures and therefore heavy and expensive machines . Moreover said method can lead to deformations of the sheet, such as sink marks , flaws or the like near the three- dimensional structures, in particular on the side of the sheet free of said three-dimensional structures, or it can cause the projecting or recessed three- dimensional structure to have the dimensions or shape not perfectly corresponding to the negative provided on the mould and/or counter-mould since the material injection force and/or the amount of the injected material cannot be enough to completely fill said negatives specially if the dimensions of the three- dimensional structures are large with respect to the thickness of the sheet .

The patent EP 585799 describes also a method for producing sheets with projections which method provides to supply a resin in the fluid form into the mould cavity with the mould in the non-closed condition through injection passages provided in a mould part (that is a half -mould) - Moreover a fluid is provided to be supplied still through injectors provided in the half -mould. Fluid injectors have a capillary end at the bottom of the projection negative and they act for supplying a blowing agent which form voids inside the projection such to facilitate the cooling at the intersection between the resin layer and the projections. The fluid supplied through the injectors passing through the thickness of the mould is not a supply of material for making the three-dimensional projecting structures but it allows a specific material to be supplied which generates voids into the projection as shown in figure 3 due to the fact that it undergoes foaming .

These moulds with injection passages provided within the thickness of the two half-moulds constituting the mould are considerably expensive and complicated. Moreover the material supplied into the area surrounding the intersection between the sheet and the projecting structure during the moulding process is a gas that therefore provides a lower resistance to the injection than a plastic material and it does not need to be fluidized in order to be supplied. Therefore the process is not much suitable for supplying a material having a higher viscosity with respect to a gas , such as softened or fluidified plastic material also enriched with mineral and/or vegetable fillers . The injection of plastic material otherwise would require moulds provided with injection devices and passages , made within the thickness of the mould, able to exert and withstand the high pressures necessary for supplying into the mould cavity a softened or plasticized material , different than gas .

The injection of a material, different than a gas or anyway with a low fluidity level , into the mould cavity through passages made within the thickness of the two half -moulds requires the presence of injection systems , systems for keeping the temperature of the mould and/or passages and/or materials that can be injected which systems increase the structural complexity of the mould and so the costs for producing these sheets .

It is also known to combine compression moulding with injection moulding, such as for example described in the patent EP 1 153 725. In such a process , the two- dimensional part is moulded by compression moulding while the three-dimensional parts or inserts are moulded by the injection of a material compatible with the material of the sheet . However, an injection moulding machine and a mould capable of withstanding high pressures are still necessary, thereby increasing the cost of the process .

Moreover the process described in the patent has a further drawback. The patent EF 1153725 therefore describes a method for making three-dimensional projecting structures by injection into a hot mould through passages made within the thickness of the half- mould. Since the pressure employed for injecting this material can be high, the patent provides the contact area 36 between the projecting structure and the plate L to have a small dimension such to reduce the pressure exerted by the injected material on the plate L. The narrow section 36 of contact between the moulding seat 18 and the plate L reduces the pressure of the injected material against said plate L and thus prevents the injected material from damaging the plate L and the upholstery sheet R. However the dimension of the section 36 has to be such to guarantee an anchoring area between the plate L and the insert 22.

Therefore this injection method used for forming three-dimensional structures , due to the pressure necessary to inject the material , is not suitable for forming three-dimensional projecting structures having a wide area in contact with the sheet since the pressure exerted by the injected material could be such to cause the sheet to be deformed. A further method for producing structured sheets is to produce inserts by injection moulding separately from the hot compression moulding of the sheet and said inserts subsequently are mechanically anchored for example by means of a screw, a snap-in pin or the like to the surface of moulded sheet . Said method allows inserts to be obtained with any shape and size applied on the sheet but it requires a longer production time and the provision of several apparatuses such as a structure for the injection moulding and one for the hot compression moulding in addition to provide, together with molding and injection steps, an operating step in which the inserts are attached to the relative moulded sheets .

From the patent US 2008/0246184 it is also known a process for moulding plastic sheets, which sheets have, locally, a three-dimensional projecting or recessed structure, which process provides a plasticized or softened blank sheet to be placed between the two parts of a mould. The surface of at least one of the two half -moulds intended to contact the surface of the second half -mould comprises a cavity for forming the sheet and at least a negative structure corresponding to the one of said three-dimensional structure, and, upon the closure of the mould, the plasticized or softened material constituting the blank sheet is forced to flow into the negative structure . Near the negative structure on at least one part of the mould a projecting feature is provided, said projecting feature being intended to cause the material of the sheet to flow towards the negative structure and/or to provide a local supply capable of supplying the material constituting the plasticized or softened sheet within the negative structure upon the closure of the mould. The provision of a projecting feature near the negative structure reduces the length of the paths the plasticized or softened material of the sheet has to follow during moulding .

When the feature is projecting within the mould cavity and is fixed it allows to reduce the gap between the two parts of the moulds when the latter is closed, such to force the material of the sheet to enter into the negative structure and to make the three- dimensional structure of the sheet ,

When the feature is projecting and movable , that is it can be retracted into the thickness of a part of the mould when it is closed, it allows , as shown in figure 5b, the area of the blank sheet to be locally increased, since with the mould in the open condition it raises the blank sheet near the negative structure , forming an excess area of the blank sheet and thus providing, upon the closure of the mould, the material necessary for producing the three-dimensional projecting structure . The height of the projecting feature is defined such to provide the amount of material necessary to make the three-dimensional structure . According to the patent therefore a material different than that constituting the supporting layer of the three-dimensional structure is not supplied : the material of the supporting layer is the same as the three-dimensional structure.

As an alternative or in combination with said projecting feature it is possible to provide near the negative structure on at least one part of the mould a recessed feature in the mould structure, intended to receive, from the negative structure, the material of the three-dimensional recessed structure , upon the closure of the mould .

By said method it is possible to produce only three-dimensional structures projecting from the sheet or three-dimensional recessed structures made of the same material as the supporting layer .

By said method it is further possible to produce three-dimensional structures from thin sheets , preferably having a thickness ranging from 2 to 3 mm, and it is not suitable for forming considerably large three-dimensional structures .

It is not possible for the sheets produced with the methods described above to have three-dimensional projecting structures or inserts with considerable dimensions , with reference to their height and to the area anchored to the sheet , with respect to the dimensions of the sheet , in particular with reference to the thickness thereof, and in addition to have three-dimensional projecting structures made of a material different than, even non compatible with the material of the layer supporting said structures , unless said inserts are made separately from the sheet and later attached to said sheet , for example by screws or glue . Moreover the methods described above for producing sheets with three-dimensional structures are considerably expensive and/or time consuming since they provide the use of moulds with injection systems with injection passages made within the thickness of the mould and with systems for heating the mould and/or the passages, therefore they involve the use of moulds that are complicated from the structural point of view.

In particular the injection system described in the patent EP 585799 is used for supplying a gas and not a softened plastic material , which requires, in order to be supplied, systems able to exert even high pressures and systems able to generate heat in order to maintain the material to be injected in the fluid state . The injection system therefore is not much suitable for producing three-dimensional projecting structures in particular three-dimensional projecting structures made of a plastic material that is not much fluid such as a thermoplastic material filled with natural and/or synthetic fibree or with mineral fillers.

Even the injection system described in the patent EP 1153725 has some drawbacks since, in order not to cause the supporting layer to be deformed due to the pressure exerted by the injected material, it requires the surface for the mutual attachment between the insert 22 and the plate L to be reduced: the more is the density of the material to be supplied, the more is the pressure necessary to supply the material into the negative of the three-dimensional structure of the mould and the more are the risks to deform the supporting layer at the area where the three- dimensional projecting structure is anchored to the supporting layer .

The aim of the present invention is to provide a sheet with three-dimensional pattern provided with three-dimensional projecting structures having any shape and size, arranged in a continuous or discontinuous manner, and provided on one or both the faces of said sheet , which sheet can be used in any application field.

The sheet of the present invention can have stiffening structures or projections having a density gradient able to efficiently absorb mechanical stresses and thus to efficiently strengthen the sheet .

A further aim of the present invention is to provide a sheet with three-dimensional projecting structures that can be obtained both by hot compression moulding and by moulding and laying down the material with the mould in the open condition into the negatives of the mould or on the supporting layer near said negatives that is by reducing the use of apparatuses , particularly avoiding expensive and complicated moulds provided with injection systems and with systems heating the passages from being used, and by reducing the steps necessary to obtain the finished products and by reducing the amount of material used .

Therefore the aim of the present invention is to provide a method for producing sheets with three- dimensional structures which method is simple and inexpensive, due to the fact that it is possible to use simple moulds , to reduce production time , for example by simplifying the sheet forming process and preventing the process from being stopped for example because of the injection system being clogged or because of a malfunction of the system heating the injection passages which can cause the material to be not enough fluid and so making the material not suitable for filling the negative .

A further aim of the present invention is to provide a method for producing sheets with three- dimensional projecting structures which three- dimensional structures can have a base for the anchorage to the supporting layer having any shape and size, which has not to be necessarily small for preventing the supporting layer from being damaged during the process injecting the material that will form the projection.

A further aim of the present invention is to provide a product that can be used not only for the outer/interior lining of motor vehicles but that can be used in any application field thanks to its properties of resistance against mechanical stresses , against chemical and physical agents , its weathering resistance and thanks to its improved aesthetic properties .

A further aim of the present invention is to provide sheets or products with three-dimensional pattern made by reducing the amount of material used, in particular the amount of expensive raw materials such to have a sheet that is contemporaneously inexpensive, easy to be produced and with a reduced weight .

The aims described above are achieved by providing a sheet with three-dimensional pattern provided with three-dimensional structures projecting with respect to the two-dimensional surface subtended by the sheet comprising at least one supporting layer composed of a single material layer or several superimposed layers , which at least one material layer has one or more three-dimensional projecting structures provided on one or both faces of said material layer and wherein said three-dimensional structure or structures and said at least one material layer constituting the supporting layer are composed of a compound or a mixture of several compounds of natural and/or synthetic origin, said three-dimensional structure or structures being made at least partially of a compound or a mixture of several compounds different than the compound or the mixture of compounds of the material supporting layer from where the three-dimensional structure projects .

In particular said at least one material layer is composed of a compound or a mixture of several compounds , and said compound or said mixture being chemically or physically compatible with the compound or mixture of several compounds of at least a part of said one three-dimensional structure .

As an alternative it is possible to provide the compound or the mixture constituting the material layer to be different from and/or chemically or physically non compatible with the compound or the mixture of one or more compounds constituting at least a part of said at least one three-dimensional structure .

If the sheet is provided with two or more three- dimensional structures , each one of said three- dimensional structures being composed of a compound or a mixture of several compounds , it is possible to provide said compound or said mixtures to be different one another and/or different from the compound or mixture of several compounds constituting the material layer supporting said three-dimensional structures .

The sheet according to the present invention allows an anchorage area between the three-dimensional projecting structure and the supporting layer to be obtained with any shape and size , even with considerably large dimensions . Thanks to the method producing said sheet there are no deformation problems for the supporting layer during the forming process , since injection pressures are not applied on the supporting layer for forming the three-dimensional projecting structures . The fact that it is possible to have an anchorage area that is not small , allows the stability of the three-dimensional structure to be increased, without risks of being broken or removed even under high and repeated stresses ,

Moreover the ratio of the volume of the supporting material layer to the volume of the three-dimensional structures is provided to have a specific value, preferably greater than 0,02.

The method according to the present invention therefore allows sheets with three-dimensional pattern provided with three-dimensional projecting structures to be obtained which three-dimensional structures defined by the portions projecting in the direction transversal to the two dimensions defining the area of the supporting layer have a ratio of the volume to the volume of the material supporting layer greater than 0,02.

This means that it is possible to have sheets with three-dimensional projecting structures that are for example high and narrow or short and wide , the main point is that the ratio of the volume of the supporting layer to the three-dimensional structure or structures has to be greater than 0,02.

The method for producing the sheet according to the present invention is particularly advantageous if such ratio is maintained .

Typically the sheets of the present invention have a size of about one metre that is they are sheets with a supporting layer ranging from 1 to 3 m ² with three - dimensional structures of some centimeters , both as regards the length, width and thickness dimension .

In the case of different volume ratios , due for example to the presence on the sheet of several small localized projections it could be more advantageous and more rapid to form two or more material supporting layers in order to increase the strength of the sheet .

Therefore the method of the present invention is particularly suitable for forming sheets having such a thickness able to suitably supporting several three- dimensional structures having a medium volume . It is not advantageous to produce thin sheets with heavy, big three-dimensional structures , or sheets with a considerable number of small three-dimensional Moreover the thickness of the three-dimensional structure or structures is provided to be equal to or higher than 1 mm while the thickness of the material layer, supporting said structures, is provided to be equal to or greater than 0,5 mm.

These characteristics allow sheets with three- dimensional pattern provided with three - dimensionai structures of any shape and size to be obtained, that is three-dimensional structures having also a great thickness with respect to the material supporting layer, with chemical and/or physical properties different one another or also different than the material layer, without making their production process complicated or more expensive and longer .

The method for producing the sheets of the present invention allows moulds with a simple structure to be used which are free of complicated injection systems , of systems for maintaining the temperature , of hot passages made within the thickness of the mould, which systems complicate the mould structure making the mould more expensive and making the processes using such moulds more long, expensive and complicated.

According to the present invention the material , as described in more details below, is arranged between the two parts of a half -mould, within the mould cavity, without injecting material through passages made within the thickness of the mould and without using a mould with hot injection passages and without pressurized injection systems .

The method of the present invention therefore allows cold moulds to be used.

The fact of not providing an injection step avoids the production of the sheet to be subjected to problems for example due to malfunctions of the pressurized injection system or to the injection passages being clogged.

These and other characteristics and advantages of the present invention will be more clear from the following description of some embodiments shown in annexed drawings wherein :

Figure 1 is a perspective view of one face of the sheet with three-dimensional pattern provided with three-dimensional projecting structures ,

Figure 2 is a perspective view of the sheet provided with three-dimensional projecting structures like ribs on one face ,

Figure 3 is a part section of a three-dimensional structure of a sheet provided with a finishing layer on the face free of projections ,

Figure 4 is a part section of a sheet provided with three-dimensional projecting structures on both the faces of the material layer ,

Figure 5 is a part section of several three- dimensional structures of a sheet provided with a finishing layer on the face provided with said projections , Figure 6 is a perspective view of a sheet provided with an anchoring layer and with a finishing layer on the face free of projections ,

Figure 7 is a part section of a three-dimensional structure provided with an adhesion layer between said three-dimensional structure and the material layer supporting said structure ,

Figure 8 is a part section of a three-dimensional structure made at least partially of a material different than the material of the material layer supporting the structures ,

Figure 9 is a part section of a sheet wherein the three-dimensional projecting structure is composed of two portions made with different materials and joined together by an adhesion layer, the face of said sheet free of three-dimensional structures being provided with an anchoring layer and a finishing layer,

Figure 10 is a part section of a sheet with three- dimensional projecting structures on both the faces , which faces are both covered by a coating layer,

Figures 11 to 14 are some embodiments of said sheets .

As shown in the figures the sheet 1 with three- dimensional pattern comprises at least one material layer 101 constituting the layer supporting said three- dimensional structures provided on one or both the faces of said material layer 101.

Said material layer 101, composed of a compound or a mixture of compounds of natural and/or synthetic origin, can be made of a thermoplastic material such as for example polypropylene, polyethylene, polystyrene , poiymethyl methacrylate , polycarbonate , nylon, rubber or the like or a mixture thereof .

In particular the material layer 101 is made of a thermoplastic material pure or filled with substances in the form of granules , particles , powders or fibres , particularly of the natural and/or synthetic type , such as wood flour, vegetable fibres , polymer fibres , glass fibres , carbon fibres , basalt fibres , talc , calcium carbonate , silica, clay, micronized and/or nanometric compounds , inert polymers , reactive polymers, functional additives or the like .

According to a further embodiment the material layer 101 can be made of thermosetting plastic material pure or filled with substances in the form of granules , particles, powders or fibres , particularly of the natural and/or synthetic type , such as wood flour, vegetable fibres , polymer fibres , glass fibres , carbon fibres, basalt fibres , talc , calcium, carbonate , silica, clay, micronized and/or nanometric compounds , inert polymers , reactive polymers , functional additives or the like.

Clearly it is possible to provide the material layer 101 to be made of one or more pure thermoplastic or thermosetting plastic material , or a mixture thereof , that is without adding any further component . It can be advantageous to use polyolefin materials such as polypropylene, polyethylene and/or polystyrene, ABS , polyesters , polyurethanes , polyamides , polyimides but also rubbers or the like . Por example it is possible to use thermoplastic elastomers, so called TPEs, which are a family of "rubber like" materials combining the best properties of thermosetting rubbers with the processing advantages of the thermoplastic materials .

It is also possible to provide a material layer 101 composed of a mixture of at least one plastic material , of the type described above , with an inert filler, such as talc, calcium carbonate, barium sulphate, silica, silicates or wood flour or the like, and/or reinforcing structures made of fibres of other plastic or non plastic materials . These fibres, particularly long fibres, are usually used in the form of mat, fabrics, nonwoven fabrics, nets or the like, composed of both natural and synthetic fibres, which are layers coupled by compression, lamination or glueing to the sheets made of plastic material pure or filled with vegetable and/or mineral fillers, preferably but not limited to, in the granular or flour form and can facilitate the interlocking of materials that are non compatible with each other.

As an alternative or in combination with the filler in the granular form it is possible to provide the use of long and/or short synthetic or natural fibres.

Fibres can be of the homogeneous type or can be made of a mixture of long and/or short vegetable and/or synthetic and/or mineral fibres, of different types .

Fibres can be homogeneous or non-homogeneous as regards their lengths for example it is possible to

IS provide a type of fibres within a mixture to have a specific length, which is different for each type, or the length homogeneity can be extended to all the types within a possible mixture .

As regards the orientation of the fibres these can be oriented substantially parallel each other, at least partially, or different orientations for each type can be provided or a random and irregular arrangement can be provided for all or a part of the fibres .

It is possible to use vegetable fibres like long fibres of cellulose, Sisal, Jute, coco, hemp, Kenaf , flax, palm, ramie, abaca, curaua, cabuya, opuntia, kapok or the like or mixtures of said fibres as vegetable long fibres .

It is possible to use polyolefin, polyester, aramld long fibres or the like or mixtures of said synthetic fibres, as the synthetic fibres, while as regards mineral fibres it is possible to use glass, basalt , carbon long fibres or the like, which fibres increase the mechanical strength of the sheet .

It is possible to provide the use of chemical and/or physical blowing agents for the material layer 101 described above which cause the sheet to be foamed during the production process, such as carbon dioxide, nitrogen, helium, butane, low boiling point hydrocarbon compounds , HFC, azodicarboamide, Oxybis, sodium bicarbonate, sodium bicarbonate and citric acid mixtures or a mixture of acid and/or basic compounds such that they are activated at the extrusion or moulding temperatures of the material and are able to release gas or gas mixtures mainly composed of C0 ₂ .

According to an improvement the mixture can also comprise a further waterproofing/compatibilizing agent for the vegetable component such to make the non-polar matrix of the polyolefin compatible with a polar filler, such as for example the vegetable fibre and such to prevent the vegetable component from absorbing the gas or the blowing agent and so preventing the foaming effect of the mixture of plastic material from being reduced.

Organic molecules with hydrophilic substituents that is titanate, silane or organo-silane, zircoaluminate or aluminate compounds , particularly maleic anhydride-modified polyolefins can be used as the waterproofing/compatibilizing agent .

According to a variant embodiment the material layer 101 can be made of a mixture of plastic materials and a vegetable and/or mineral material filler comprising cork flour, which is particularly suitable for making sound or heat insulation panels and for panels with a particularly reduced density.

It is possible to provide the sheet 1 with three- dimensional pattern to be composed of a single material layer 101 according to one of the above mentioned variants or to be composed of two or more layers 101 which layers 101 can have the same or different composition and it is possible to provide compounds , glues, laminates , foils, nets of material or the like which promote the compatibility and bonding of two or more layers 101 together. According to the present invention the fact of providing compatibilizing agents for the polymer matrix and the vegetable matrix allows the sheet to increase its weathering resistance, in particular to moisture, and consequently it allows the life cycle of the sheet 1 to be extended.

The material of the layer 101 when heated has such a fluidity degree that causes said layer 101 to be deformed within the negatives, of the three-dimensional structures , provided in a mould.

According to a further variant it is possible to provide the sheet with three-dimensional pattern to be made of one or more layers 101 supporting the three- dimensional structures composed of natural and/or synthetic and/or mineral fibres .

Said fibres , preferably long fibres, for example of vegetable origin, are stranded together such to form a mat, a fabric, a pad or a net or the like, and said fibres after having been compressed together into a mould form a supporting layer 101 for one or more three-dimensional projecting structures 102 arranged on one or both the faces of the sheet, which sheet will be particularly resistant to mechanical stresses, to breaking while having a very reduced weight .

The origin of said fibres, constituting the supporting layer 101, obviously can be homogeneous or the pad or the net can be made of fibres of different types . As regards the orientation, they can be oriented at least partially substantially parallel to each other, or can have different orientations , for example different orientations for each type or a random and irregular orientation.

The sheet 1 according to the present invention can have three-dimensional projecting structures 102 on one or both the faces 111, 112 of the layer 101.

Preferably said three-dimensional structures are provided as projections 102 outwardly extending from one or both the faces 111, 112 of said layer 101 and said projections 102 can be composed of one or more ribs and/or one or more cone or column-like projections randomly or orderly arranged on one or both the faces 111, 112 of said layer 101. The number, the shape and the arrangement of said projections 102 depend on how the sheet 1 of the present invention is used.

According to a preferred embodiment the ratio of the volume of the material layer 101 to the volume of the sum of the three-dimensional structures or projections 102 on the sheet is greater than 0,02. Moreover for the sheet 1 object of the present invention it is possible to provide :

- the thickness that is the height h of the three-dimensional structure or projection 102 to be equal to or greater than 1 mm, - the thickness that is the height H of the material layer 101 to be equal to or greater than 0 , 5 mm.

Said three-dimensional projecting structures or projections 102 improve the functionality and increase the possibilities for using the sheet 1 with the three- dimensional pattern. Said projections can be:

- stiffening projections affecting the properties of resistance to mechanical stresses of the finished sheet 1, - functional attachment projections allowing the sheet 1 to be attached or joined to other elements or parts,

- functional attachment projections allowing any elements to be introduced or fastened and/or secured to the sheet 1,

- shock resistant projections

- vibration resistant projections,

- damping projections,

- projections serving as spacing supports, - projections made of a material intended for - the packaging and/or thermal, vibration, ultrasonic welding or the like .

By means of the sheet 1 object of the present invention it is possible to have three-dimensional structures or projections 102 with any shape provided that the ratio of the volume of the material layer 101 to the volume of the projection or projections 102 provided on the sheet is maintained.

For example said three-dimensional projecting strctures 102 can have a cone-like shape, such as shown in figure 1, a cylindrical shape such as shown in figure 3 , a parallelepiped shape such as shown in figure 2 or they can form hooks, supports , spacers, anti-shock plugs, stiffening ribs or webs giving specific functions to the sheet 1. According to a preferred embodiment the ratio of the highest achievable height of said three-dimensional structures 102 , in mm, to the cross-section of the three-dimensional structure 102 at its base connecting to the material layer 101, in mm ² , may be equal to 40 mm ¹ .

According to the present invention said three- dimensional structure or structures 102 and said at least one material layer constituting the supporting layer 101 are composed of a compound or a mixture of several compounds of natural and/or synthetic origin, said three-dimensional structure or structures 102 being composed at least partially of a compound or a mixture of several compounds different than the compound or mixture of compounds constituting the material supporting layer 101 from which the three- dimensional structure 102 projects .

For example the three-dimensional projecting structure can be at least partially composed of a layer 103 for the anchorage to the supporting layer 101, which layer has a composition different than the supporting layer 101 and/or then the remaining part of the three-dimensional structure 102. Therefore it is possible to provide for example the three-dimensional structure 102 to be composed of a material having the same composition as the material supporting layer 101 and to provide said three-dimensional structure to have a base anchoring to the supporting layer 101, composed of an adhesion layer 103 having a composition different than the material constituting the supporting layer 101 and the projection 102.

According to one embodiment of the present invention the three-dimensional structures 102 of the sheet 1 are made of the same material as the material layer 101.

According to a variant of the present invention said projections 102 are composed of a material different than the material layer 101.

Any material can be used for making the projections , in particular it is poesible to uee one or more of the compounds described above for making the layer 101.

Por example the three-dimensional structures can be made of a thermoplastic or thermosetting material pure or mixed with other substances, such as natural and/or synthetic fibres and/or vegetable and/or mineral fillers, for example they can be made of pure polypropylene , rubber, nylon.

For example, in order to obtain a sheet with three-dimensional projecting structures 102 which sheet has a high mechanical strength, in particular a high impact and breaking strength, and at the same time is light and inexpensive, it is possible to provide the material layer 101 to be as a pad of natural and/or mineral fibres , which are pressed together during the forming process of the sheet by clamping the mould and the countermould, and it is possible to make one or more thermoformable three-dimensional projecting structures 102 by applying a compound or a mixture of several plastic substances, for example pure polypropylene or rubber or the like, inside the negative or on the layer 101 at the negative of said three-dimensional structure or structures 102.

According to a further variant said projections 102 can be provided as to be made partially of the same material as the layer 101 and partially of a different material .

In particular, as shown in the figures 8 and 9, for example with reference to three-dimensional projecting structures having considerable height, width and length dimensions with respect to the material layer 101 it is poseible to provide the portion of the projection 102 in contact with the layer 101, that is the base portion of said projection 102 , to be made of the same material as said layer 101, while the top portion of said projection 102 to be composed of a different material .

It is also poseible to provide the three- dimensional structure 102 to be composed of a compound or a mixture of several compounds that is different but chemically or physically compatible with the compound or the mixture of several compounds constituting the layer 101 or to provide said compound or said mixture of the three-dimensional structure 102 to be non compatible with the compound or mixture of the layer 101.

Compounds or mixtures of several compounds compatible with each other mean at least two mixtures of chemical compounds , or two compounds , that even if are different one another as regards the nature or the amount of the substances constituting them, are able to interact together, under specific conditions, for example as regards temperature and pressure, by adhesion, cohesion and/or chemical bonds between at least one of the substances constituting such mixtures and they allow finished structures to be obtained, composed of both the mixtures , or of individual compounds , which stable over time as regards the chemical/physical perspective .

Compound or mixtures of several compounds non compatible with one another mean at least two mixtures or compounds which are different as regards the nature or amount of the substances constituting them, which substances of the two mixtures are not able to lead to any adhesion, cohesion bonds stable and lasting over time without the use of at least one additional component .

According to the present invention it is poesible to provide the same sheet 1 with three-dimensional structures 102 that are different as regards the shape, dimensions and composition which composition can change not only from one three-dimensional structure 102 to another one but also with respect to the composition of the material layer 101.

By changing the composition of the material layer

101 and/or of one or more three-dimensional structures

102 it is poesible to give the sheet 1 a specific resistance to mechanical stresses and to the abrasion: this can be obtained by using for example a mixture of polymers resistant to mechanical stresses or to abrasion and/or by using additive compounds or fillers able to enhance said properties such as for example silica or the like.

By means of this variety it is possible to obtain by the same process structured sheets 1 having different functions that can be applied in any fields that is not only for the interior lining of motor vehicles, but also for furniture, insulating walls or the like.

Moreover the fact that it is possible to introduce colour pigments into the composition of the material layer 101 and/or in the composition of the three- dimensional structures 102 leads to the possibility of having a sheet 1 that is coloured or with multicolour effects considerably improving the aesthetic appearance .

According to a further embodiment between the compound or mixture constituting the material layer 101 from where the three~dlmensional structures 102 project and the compound or mixture constituting at least a portion of said at least one three-dimensional structure 102 there is provided at least one adhesion layer 103 promoting the adhesion and/or cohesion of said three-dimensional structure 102 or portion of said three-dimensional structure (102) with said material layer 101.

It is possible to provide an adhesion layer also between two or more material layers constituting the layer supporting the three-dimensional projecting structure or structures 102. As shown in the figure 7 and 9 in the case where all or a portion of said three-dimensional projecting structure 102 is composed of a material different from and/or non compatible with the material of the layer 101 it is possible to provide at the base of the three- dimensional projecting structure 102, between said projection 102 or projection portion and said material layer 101, the presence of one adhesion layer 103 promoting the adhesion and/or cohesion of said projection or projection portion to said material layer 101.

Obviously it is possible to provide the adhesion layer 103 at the base of the three-dimensional projecting structure 102 to extend for a certain area of the supporting material layer, the area of said layer being greater than the area of the base anchoring the supporting layer 101 to said at least one three- dimensional projecting structure .

Said adhesion layer 103 that improves the adhesion and/or compatibility between the material of the projection 102 and the material of the layer 101, for example in the case of projections made of ABS applied on layers made of polypropylene, can be composed of at least one of or a combination of:

- a nonwoven fabric compatible with one or both the materials of the projection 102 and of the material layer 101, - a nonwoven fabric able to adhere against one or both the materials of the projection 102 and of the material layer 101 for the mechanical interlocking,

- a nonwoven fabric compatible with and/or able to adhere by mechanical interlocking to one or both the materials of the projection 102 and of the material layer

101,

- a nonwoven fabric made of different types of materials such as polypropylene , cellulose, polyesther or the like,

- a net of mineral, synthetic, natural fibres able to adhere against said three- dimensional structures 102 and/or to the material layer 101 by chemical/physical compatibility or by mechanical interlocking,

a net of thermoplastic and/or thermosetting - polymers able to adhere against said three- dimensional structures 102 and/or to the material layer 101 by chemical/physical compatibility or by mechanical interlocking,

- a pad made of fabric, natural fibres, synthetic fibres , mineral fibres , polymers, and/or a mixture thereof able to adhere against said three-dimensional structures

102 and/or against the material layer 101 by chemical/physical compatibility or by mechanical interlocking .

Obviously it is possible to provide said adhesion layer 103 to be provided, between the material layer 101 and the three-dimensional structure 102, also when said at least one three-dimensional strcuture has a composition equal to or compatible with the material layer 101.

Said adhesion layer 103 can also be provided not only at the base of the three-dimensional structure but in any location within the thickness of the three- dimensional structure 102 , in a position substantially parallel to the base of the three-dimensional structure 102, such that said three-dimensional structure 102 is divided into at least two portions .

It is also possible to provide several layers 103 , from the base along all or a part of the thickness or height of the three-dimensional structure 102 such to form a kind of "sandwich" that is a multi- layer three- dimensional structure 102 composed of several layers having a different composition leading to three- dimensional structures 102 with specific strength and flexibility properties .

Said adhesion layer 103 in addition to improve the adhesion between the three-dimensional structure 102 and the material layer 101 and/or the adhesion between two portions of a three-dimensional structure 102, can be used for enchancing the properties of the finished sheet 1.

According to a variant embodiment it is possible to provide at least a part of the face 111 or 112 of the material layer 101 supporting the three-dimensional structures 102 , preferably the face of the layer 101 in contact with the base of the three-dimensional structure 102 to be coated by a layer 103 , for example a fabric, contributing in reducing vibrations and/or noises absorbed by the sheet 1.

It is clearly possible that, in order to give specific properties to the finished sheet 1, said layer 103 covers at least a part of the face 111 or 112 of the layer 101 supporting the three-dimensional structures 102 , such to cover not only the layer 101 but also the three-dimensional structures 102.

The sheet 1 object of the present invention can have one or more three-dimensional structures on both the faces 111, 112. In a variant the sheet 1 has the three-dimensional structure or structures 102 only on one of its faces . On the surface of the face free from three-dimensional structures, or on both the faces 111, 112 , there is provided a monolayered or multllayered finishing layer 104 which covers all or part of the surface of said face or faces 111, 112 , said finishing layer 104 having an aesthetic and/or protective function for the material layer 101 and/or for at least one of the three-dimensional structures 102.

The finishing layer 104 can be composed of a cloth, a fabric, a nonwoven fabric, of films of plastic material such as PVC, films of leather, films of imitation leather, melamine adhesives, films of natural material such as hide or the like. For example the coating and finishing film 104 can be composed of polyester, viscose, polypropylene , nylon, mixed cotton, PVC, melamine material, TPE (thermoplastic elastomers) , TPO (olefin based thermoplastic elastomers) or the like or said coating and finishing layer 104 can be composed of several layers having a different composition for example a fabric with a support made of foamed polymer in order to give the finished sheet 1 softness touch properties or a pad of natural and/or synthetic and/or mineral fibres such as cotton, cellulose. Sisal fibres, juta, coco, hemp, Kenaf , flax, palm, ramie, abaca, curaua, cabuya, opuntia, kapok glass fibres , basalt or the like.

Said outer finishing and coating layer 104 can be coloured by adding to the composition mixture natural or synthetic dyes .

The finishing layer 104 has not only an aesthetic and protective function for the sheet 1, but by its chemical/physical characteristics allows sheets 1 with a three-dimensional pattern to be made with specific properties for example insulating sheets able to absorb noises and/or vibrations .

According to the present invention the mixture constituting the material layer 101, and/or the three- dimensional structures 102 and/or the finishing layer 104 contains also additives giving a higher resistance against chemical and/or physical agent, weathering resistance, particularly to UV radiation, to ozone, generally allowing the sheet 1 to have a greater resistance to ageing. For example in the compound constituting the material layer 101 and/or the three- dimensional structures 102 and/or the finishing layer 104 it is possible to mix compounds such as light stabilizers, such as hindered amines (known as HALS = Hindered Amines Light Stabilizers) , UV stabilizers, antioxidants, UV absorbers, substances retarding or preventing the action of free radicals (scavengers) , or more in general pigments or the like which inhibit free radicals forming at the beginning of the polymer degradation process , a process caused by light action, which retard or inhibit the degradation of said polymers above all in sheets 1 made for outdoor use.

Obviously it is possible to provide said finishing layer 104 to be a multilayer and to be provided, at least partially, not only on one face but on both the faces 111, 112 of the sheet 1, such that also the projecting or recessed three-dimensional structures 102 are covered. It is also possible to provide the composition and/or the thickness of the finishing layer 104 to be different for the two faces 111, 112 of the sheet 1: for example it is possible to provide the coating layer covering the sheet face 112 to have such composition and/or dimension properties to aesthetically improve the visual and touch appearance of the finished layer 1 while the coating layer 104 covering the face 111 of the sheet 1 can have such properties and dimensions , for example such a thickness to improve the mechanical strength of the sheet 1.

It is advantageous for making the finishing layer

104 to arrange an anchoring layer 105 between the material layer 101, with or without at least one three- dimensional structure 102 , and the outer finishing layer 104 , for example a fibrous fabric made of natural and/or synthetic fibres such as cotton and/or glass fibres.

As shown in figure 10 it is possible to provide said anchoring layer 105 between the layer 101 and/or the three-dimensional structures 102 and the finishing layer 104 to have the same properties, especially the same composition as the adhesion layer 103 described above .

Obviously it is possible to provide said finishing layer 104 and said ancoring layer 105 on both the faces 111, 112 of the material layer 101 of the sheet 1 and to cover at least partially also the three-dimensional structures 102 provided on said sheet 1.

Said anchoring layer 105 leads to a more firm and lasting bonding between the material layer 101 and/or the three-dimensional structures 102 and the outer finshing layer 104 , each one for example compoeed of different types of materials .

Said anchoring layer 105 can be for example made of a film whose surface faced outwardly is compatible with and able to be attached to the outer finishing layer 104 of the sheet 1 while the surface faced towards the core of the sheet 1 is compatible and able to be attached to the material layer 101 and/or to the three-dimensional structures 102 of said sheet 1.

A method for making sheets 1 object of the present invention provides the use of a mould whose inner surface of at least one mould part, or half -mould, has a cavity for forming the sheet 1 and at least one negative structure corresponding to that of said at least one three-dimensional projecting structure 102 , at least one layer 101 supporting the three-dimensional projecting structure or structures and/or said at least one three-dimensional projecting structure 102 being formed after the closure of the mould that is after the two half -moulds are brought near one another and clamped together .

The process provides one or more of the following steps :

- supplying additional material 122 by filling at least one negative structure with the mould in the open condition,

- arranging at least a plasticized or softened supporting material layer 101 between the two portions of a mould with the mould in the open condition,

- laying down additional material 122 on the supporting material layer 101 at least near one negative structure with the mould in the open condition,

- compressing and forcing at least a part of the material layer 101 in the plasticized, softened, fluid or semi-fluid condition, to flow into the negative structure by means of a feature intended to project into the mould cavity, said feature being intended to locally reduce the gap between the two parts of a mould when it it closed such to help a part of the material of the supporting layer 101 to flow towards the negative structure and/or said feature being intended to locally increase within the mould cavity the area of the material layer 101 in order to form a local supply of said material 101 able to fill at least partially the negative structure, when the mould is closed, in order to form at least a portion of at least one three- dimensional projecting structure 102.

Said additional material 122 is intended to constitute at least a portion of a three-dimensional projecting structure 102 of the sheet 1 and said steps are provided in combination or alternatively one another such that said at least one three-dimensional projecting structure 102 is composed at least partially of the material constituting the supporting layer 101 and/or of the additional material .

If the material constituting at least one supporting layer 101 is in a plastlcized, softened, fluid or semifluid condition, it is possible to force said plasticized or softened material to flow into the negative structure .

Near the negative structure on at least a part of the mould there can be provided a projecting feature, said projecting feature being intended to help the material of the sheet to flow towards the negative structure and/or to form a local supply of the same material of the supporting layer 101 able to fill at least partially the negative structure when the mould is closed. Thus it is possible to make structured sheets 1 with a material layer 101 and one or more three-dimensional projecting structures 102 made of the same material as the material layer 101.

It has been found that the provision of such projecting features provided near the negative structure on at least a part of the mould reduces the length of the paths that the plasticized or softened material of the supporting layer 101 must follow during moulding, and therefore reduces the moulding pressure .

The feature of the mould provided near the negative structure is a fixed feature intended to project into the mould cavity and it acts for locally reducing the gap provided between the two portions of the mould when it is closed, such to force the material of the supporting layer 101, arranged between the two mould parts , to flow into the negative structure and to form at least a portion of the three-dimensional structure 102 of the sheet 1. The material supporting layer 101 therefore will be slightly more compressed near the three-dimensional structure made , since a part of this material 101 is forced to enter into the negative structure .

In a second variant embodiment of the process for making three-dimensional projecting structures 102 composed at least partially of the same material as the layer 101, the surface of the mould has a movable projecting feature, such as shown in figure 11, that can project or be retracted by sliding into the mould cavity when the mould is closed, which feature, provided near the negative structure, projects into the mould cavity with the mould in the open condition, when at least a material layer is arranged between the two mould parts .

Such projecting feature, that can be slidably retracted into the mould frame, may for example be mounted on a spring . When the mould is open, the feature projecting into the mould cavity raises the supporting layer 101 near the negative structure. This results in an excess area of blank sheet, corresponding to the flanks of the raised region. When the mould is closed, the spring is compressed and the projecting feature retracts into the mould. The excess amount of the material layer 101 serves to fill at least partially the negative structure, without the need of flowing the material over a long distance, the movable projecting feature being placed near said negative. The height of the projecting feature is determined so as to supply the amount of material necessary to form at least a portion of the three-dimensional projecting structure.

According to a further variant embodiment it is possible to provide the sheet with three-dimensional projecting structures 102 which have even considerable dimensions by supplying, with the mould in the open condition, into the negative structure or structures of the mould additional material, which material is supplied into said negative or negatives of the three- dimensional projecting structures 102 before arranging at least one plasticized or softened material supporting layer 101 between the two mould parts .

According to a first variant the additional material is supplied in the fluid form, both manually and mechanically, by automatic means .

A variant provides said additional material 122 to be supplied as a piece of material having predetermined dimensions and mass . Said piece of plastic material is at the solid or plastic state or already at the softened state or it is brought in this state by heating it once it is laid down on the mould. A piece of said additional material is laid down manually or by automatic means in the area of each mould part corresponding to the three~dimensioanl structure 102 of the finished sheet 1.

The amount of said additional material 122 will be enough to form all or a portion of the three- dimensional projecting structure 102 provided on the finished sheet 1.

The composition of said material added for making one or more of the three-dimensional projecting structures 102 can be equal to, compatible with, different from and/or non compatible with the composition of the material constituting the layer 101 of the sheet 1.

The amount of the additional material placed into the negative of the mould corresponding to the three- dimensional projecting structure 102 to be made can be enough for generating said structure 102 and therefore by said variant, it is possible to provide the mould used to be free from the projecting feature intended to compress the material into the negative of the mould since said negative is sufficiently filled by the additional material .

The fact of forming one or more three-dimensional projecting structures 102 by adding material in the fluid form and/or by supplying the material in the form of a piece of material having predetermined dimensions and mass, is particularly advantageous when three- dimensional structures 102 are desired to be made on a material layer 101 having a poor fluidity, even if heated into a mould, for example when the material layer 101 supporting the three-dimensional structures 101 is composed of a fibre pad. In this case the fibre pad is placed within a mould and the fibres are pressed together in order to make a layer 101 particularly resistant to impacts and breaking. Said layer of fibrous material may not have a sufficient fluidity degree to allow the negative or negatives in the mould to be filled by the material flowing. By the present invention therefore it is possible to use the fibrous material for making the particularly resistant and light supporting layer and to make three-dimensional structures 102 that are composed even of a material completely different than the material of the supporting layer 101, which material can be shaped into the negatives of the three-dimensional structures provided on the mould by means of its fluidity properties , that are greater than, or anyway different than those of the material of the supporting layer 101.

The additional material supplied or laid down into the negative according to the above described variants adheres to the material of the layer 101 or to the material the layer 101 supplied into the negative structure due to the projecting feature provided near said negative, such that only the additional material or the additional material plus the material supplied by the provision of the feature is enough to make the three-dimensional structure 102 of the sheet 1.

In order to keep the additional material supplied into the negatives of the mould in the fluid or softened condition or in order to convert the additional material laid down as a piece from the solid state to the softened state such to promote its adhesion with the material of the sheet during the formation of the three-dimensional structure or structures 102, it is possible to provide the areas of the mould involved in the supplying or in the laying down of the material , that is the negatives , to be heated, at least in the initial phase of the moulding process that is before closing the mould while the remaining portions of the mould can remain cool.

According to a variant embodiment in order to promote the adhesion between the additional material constituting at least partially the three-dimensional structure 102 of the sheet 1 and the material layer 101, especially in the case the composition of the additional material is different from and/or non compatible with the composition of the material layer 101, it is possible to provide an adhesion layer 103 to be arranged between said additional material and said material of the layer 101 which can promote the chemical/physical and/or mechanical adhesion that is the mechanical interlocking, of said materials one with respect to the other.

It is possible to place said adhesion layer 103 on a portion or on the whole additional material after filling with said fluid additional material the negative and/or to place it on the material layer 101 such to cover all or part of the face 111 and/or 112 wherein the three-dimensional projecting structures 102 are provided which are composed at least partially of said additional material that can have a composition different from and/or non compatible with the material of the layer 101.

According to a preferred embodiment , said adhesion layer 103 is placed on the material layer 101 at the base of the three-dimensional projecting structure 102 composed at least partially of said additional material .

As an alternative or in combination with the adhesion layer 103 provided at the base of the three- dimensional layer 102 one or more adhesion layere can be placed between predetermined amounts of additional material arranged into the negative or on the layer 101 at the mould negative such to create a three- dimensional structure 102 formed by interposing one or more adhesion layere with one or more portions of additional material .

The fact of producing three-dimensional structures 102 by adding material is particularly advantageous when said structures have considerable dimensions and when the thickness of the material of the initial blank sheet is not enough to fill the negatives of the mould during the moulding phases .

Moreover depending on the elasticity and strength properties of the three-dimensional projecting structures 102 desired on the finished sheet 1 and that are based on the composition of the material used for making them, the additional material can be supplied into the negatives in the fluid or semifluid form, for example if appendages or weather strips made of rubber are desired, or in the solid or semisolid state for example if stiffening ribs or appendages are desired to be made mainly composed of natural and/or synthetic fibres embedded into a polymer matrix.

The process according to the invention may be used for moulding sheets 1 with a three-dimensional pattern having three-dimensional structures 102 on both its faces . However, in one particularly advantageous version, the sheet 1 has a three-dimensional structure 102 only on one of its faces . In this version it is advantageous for that face intended to remain smooth to be covered with a monolayered or multilayered finishing layer 104 so as to improve its mechanical integrity, and to enchance its aesthetic appearance .

Moreover, in this version, the process makes it possible to obtain a smooth face, free of sink marks . This is especially advantageous when the three- dimensional structures 102 are deep, as in this case the known processes do not allow a smooth sheet "back" , free of sink marks, to be obtained. This advantage of the process according to the invention is even more pronounced when the material is a crystalline polymer, the shrinkage of which as it crystallizes causes, in a known manner, sink marks on the reverse side of the material layer 101 where three-dimensional structures 102 are provided such as ribs or overthicknesses , that is large three-dimensional structures 102.

Consequently, in one method of implementing this version, before the mould is closed, a flexible coating or finishing layer 104 is superposed on that face of the material layer 101 intended to remain smooth.

In this method of implementation, it is advantageous to place a layer of fibres that is an anchoring layer 105 between the material layer 101 and the finshing layer 104 , so as to avoid any deformation of the surface finish of the coating during moulding and to promote the adhesion of the layers 101, 104 that can have a different composition with respect to one another . It is recommended that the layer of fibres be a fibrous fabric formed from cotton fibres or glass fibres.

Obviously according to a variant of the present invention it is possible to provide a finishing layer also on that face of the sheet 1 provided with three- dimensional structures 102 : therefore a finishing layer 104 and possibly an anchoring layer 105 can be placed into the mould between the inner surface of said mould and the face of the material layer 101 and/or the material of the three-dimensional structures where the three-dimensional projecting structures will be made .

Therefore by the process described above it is possible to obtain three-dimensional structures considerably large with respect to the thickness of the sheet while keeping the projecting feature, if any, with small dimensions within the mould cavity provided at the negative structure . It has to be noted also that the additional material is supplied into the negative structure or the additional material is laid down on the material supporting layer 101 with the mould in the open condition therefore moulds do not need complicated passages suitably adjusted for injecting the material as on the contrary it is necessary according to conventional methods .

The sheet 1 object of the present invention therefore has a material layer 101 whose composition of the plastic component and the amount and/or dimensions of the natural fillers and/or of the natural and/or synthetic and/or mineral fibres can be modified allowing, depending on requirements of use, the chemical/physical properties of the finished sheet 1 to be changed such as flexibility, impact strength, compressive strength, weathering resistance, and the resistance to chemical/physical agents. Moreover the possibility of having three-dimensional structures 102 with considerable dimensions with respect to the material layer 101, for example as regards the thickness or height, and with a composition different than the layer 101 and/or different from one another, allows three-dimensional structures 102 to be composed also of special materials , such as pure plastic materials, rubbers or the like, that therefore can have chemical/physical properties different than the material layer 101 but also different among the three- dimensional structures 102 provided on the same sheet 1. All these characteristics lead to a sheet 1 with three-dimensional pattern having a wide range of use, that is easy to be produced and with low costs, since the use of special material can be limited, depending on requirements, to the material layer 101, and/or to at least one three-dimensional structure 102 and/or to a portion of said at least one three-dimensional structure 102.