MXPA99004660A - Method of preparing decorative articles - Google Patents

Abstract

Method of preparing decorative emblems comprising:(a) providing rigid substrate (1) having on the front surface (2) a 3-dimensional design having protrusions or recesses, (b) placing the substrate in a first mold (6) having an inner surface (7) which closely contacts part of the substrate front surface (2) to provide gap (8) between mold inner surface (7) and front surface (2), (c) injection molding a first plastic (9) through one or more conduits (10)extending from the back surface (5) of the substrate to the front surface (2) to fill the gap and solidifying the first plastic material, (d) covering at least part of the 3-dimensional design and first plastic material (9) with a second transparent plastic (17) to form a protective cap (18) by placing the substrate in a second mold (11) having an inner surface (12) which closely contacts part of surface (2) of the substrate (1) to provide cavity (14) into which second plastic (17) is injected.

Description

METHOD OF PREPARATION OF DECORATIVE ITEMS TECHNICAL FIELD The present invention relates to a method of preparing decorative elements comprising providing a rigid substrate having a 3-dimensional design on the front surface and covering the 3-dimensional design with a transparent material. The invention also relates to decorative elements, which are obtainable by such method and their use for automotive applications.

BACKGROUND The decorative elements comprising a rigid or flexible substrate optionally having a 3-dimensional design on the front surface, which is covered with a transparent plastic material, are described in the literature.

US Pat. No. 4,356,617 discloses a decorative emblem using a metallic foil as a substrate having markings applied by screen printing or lithographic printing. The metal sheet can be embossed later to provide a 3-dimensional design. Then a viscous, fluent plastic material such as a polyurethane is melted into the etched marks Ref. 030134 in relief optionally, which are combined together and form a meniscus which, when solidified, gives a lens effect to the resulting decorative emblem. To control the fluent plastic flow and the meniscus formation, a clearly defined peripheral edge, such as a dam, is formed, for example, during the embossing step or printed on the metal foil. The decorative emblem may comprise a layer of a pressure sensitive adhesive on the back surface of the metal sheet to allow it to adhere to the intended surface. The viscous, fluent plastic material can be selected from heat curable materials, such as polyurethanes. Radiation curable materials are, for example, described in US Pat. No. 4,087,570 or US Pat. No. 4,259,388. US Pat. No. 4,566,929 discloses a flexible fitting strip suitable for application to an automobile body comprising a prolonged molding with a longitudinal channel, a decorative surface in the channel and an impact resistant and weather resistant plastic coating having edges radios, which provide a lens effect to the decorative surface below.

US Pat. No. 4,767,674 and US Pat. No. 4,481,160 disclose decorative emblems using a bevel having a cavity formed by a generally flat base and peripheral walls or vertical vertices as a substrate, which can be formed of a plastic, such as an acrylonitrile resin -butadiene-styrene (ABS). Subsequent to an initial molding of a plastic material fluent in the cavity, a decorative sheet is placed therein and subjected to a second molding of fluent plastic material to form a lens cover on the sheet and it is completely encapsulated in plastic. The decorative sheet can be a metal sheet, which is painted with a brush, printed, embossed optionally or die to place it in the cavity. The bevel may comprise an adhesive layer on the back surface for attaching the resulting decorative emblem to the intended surface.

The decorative ornament described in JP 61-249-758 is first obtained by providing a substrate having projecting portions via the injection molding of, for example, polyvinyl chloride or ABS. Then a pigmented polyurethane resin is poured over the protruding parts and cured followed by the application of a curable, synthetic resin having a meniscus.

US Pat. No. 4,330,578 describes a process for preparing a synthetic resin decorative article comprising first forming an injection molded part, which preferably has a flat surface on which a designed pattern is printed. The molded part is then placed in a second mold to form a decorative article of synthetic resin consisting essentially of two bodies of superimposed thermoplastic resin, injection molded and at least one integral layer of a thermoset ink included within the molded bodies.

US Patent 4,427,615 describes a method for preparing injection molded plastic objects. In this method a sheet is inserted into the mold cavity, so that the sheet is pressed into the gear with the button and / or the upper part of the mold cavity by molding the injected material under pressure.

The decorative elements which are available up to now, do not meet all the aesthetic requirements to a desired degree and / or the method of their production can be complicated or expensive. It has therefore been a need to provide decorative elements which are highly attractive from an aesthetic point of view and a method of technically and economically acceptable preparation thereof.

DESCRIPTION OF THE INVENTION The invention can be summarized as a method of preparing decorative emblems comprising: (a) providing a rigid substrate (1) having on the front surface (2) a 3-dimensional design having elements (4), which form elevations or gaps with respect to the front surface (2); (b) placing the substrate in a first mold (6) having an internal surface (7), which closely contacts a portion of the front surface (2) to provide an opening (8) between the inner surface (7) ) and the recessed portions of the front surface (2); (c) injection molding a first plastic material (9) through one or more conduits (10) extending from the rear surface (5) of the substrate to the front surface (2) to allow filling the opening with the first plastic material and solidify or cure the first plastic material, (d) covering at least a part of the 3-dimensional design and the first plastic material (9) with a second transparent plastic material (17) to form a protective cover (18) by placing the substrate in a second mold (11) that has an internal surface (12), which closely contacts a part of the surface (2) of the substrate (1), thereby providing a cavity (14) in which the second plastic material is injection molded (17) ) through one or more ducts (23) extending from the back surface (5) to the front surface (2) or, alternatively, removing the substrate (1) from the first mold (6) and melting a measured amount of the second plastic material (17) on the first plastic material (17) and the 3-dimensional design.

The invention further comprises a decorative element, which is obtainable by such method and the use of the decorative emblem for automotive applications.

BRVE DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic cross-sectional view of a preferred embodiment of a decorative element according to the invention comprising as a substrate a bevel 19 with a peripheral ridge, which extends vertically 21, having on the front surface 2 a design 3-dimensional with elements 4. The first plastic material 9, which has been injection molded via the conduit 10, is placed on the front surface of the bevel 19 between the elements 4. The second transparent plastic material 17 covers the design engraved in relief of elements 4 forming a lens cover 18. The back surface 5 of the bevel 19 comprises an adhesive layer 25 with a release coater 26.

Figure 2 is a schematic cross-sectional view of another preferred embodiment of a decorative emblem according to the invention comprising a substrate 1 having a well-defined edge 22 and a 3-dimensional design of elements 4 on its front surface 2. The first plastic material 9, which has been injection molded via conduit 10, is placed on the front surface of the substrate 1 between the elements 4. The second plastic material 17 covers the 3-dimensional design of elements 4 that form a cover of lens 18.

Figure 3 is a schematic cross-sectional view of another preferred embodiment of a decorative element, which is similar to the embodiment of Figure 1, but where the bevel 19 exhibits a curved front surface 2.

Figure 4 is a schematic cross-sectional view of a bevel 19 with a vertically extending peripheral edge 21 which is placed in the first mold 6 having an internal surface 7, which closely makes contact with a part of the front surface 2 of the bevel 19, therefore provides an opening 8 between the inner surface 7 and the front surface 2 of the bevel 19.

Figure 5 is a schematic cross-sectional view of a bevel 19 with a vertically extending peripheral edge 21 which is placed in the second mold 11. The bevel exhibits a 3-dimensional design of elements 4 on its front surface 2. first colored plastic material 9, which has been injection molded via conduit 10, partially covers the front surface 2 of the bevel 19 between the elements 4. The second mold 11 has an inner surface 12 which closely contacts the bevel 19 , therefore, it provides a cavity 14 in which the second transparent plastic material can be injected via the conduit 23.

Figure 6 is a schematic top view of an oval-shaped bezel 19 having a peripheral, vertically extending rim 21 surrounding the recess 20. The front surface 2 comprises a 3-dimensional design of elements 4 that mark the word " Symbol ". The front surface which at least partially is covered between the elements 4 with the first plastic material 9, is joined with disperser means having a plurality of disperser holes 24 through which the second transparent plastic material 17 is transported. the 3-dimensional design of elements 4 and the first plastic material 9 and forming a protective cover 18.

DETAILED DESCRIPTION The decorative elements according to the present invention comprise a rigid substrate 1, which can be formed of thermoplastic or thermoset polymer materials such as, for example, acrylonitrile-butadiene-styrene (ABS), acrylonitrile-styrene-rubber copolymers ( ASA), polycarbonates, polyamides or epoxy resins or a metal or metal alloy such as zinc, aluminum or stainless steel. The plastic-like substrates can be metallized or coated with metal, for example, chromium or aluminum.

The substrate 1 comprises a front surface 2, a rear surface 5 and an edge or edges 22. The front surface 2 exhibits a 3-dimensional decorative design comprising elements 4. The elements 4 which can form elevations or gaps with respect to a appropriately defined reference level of the front surface 2, typically have an average height between 1/5 and 5, preferably between 1/3 and 3 and more preferably between 1/2 and 2 times the thickness of the substrate, which is defined as the distance between such level of the front surface 2 and the rear surface 5. An appropriate reference level of the front surface of the decorative element of Figure 1 is, for example, the base level connecting the lower ends of the elevations. The elements 4 preferably have an average height of between 0.5 and 6 millimeters and preferably between 1 and 4 millimeters. The average height of the elements is defined as the absolute average height of the elements with respect to the level of the frontal surface.

The elements can exhibit various shapes and exhibit, for example, essentially regular or irregular trapezoidal, rectangular, triangular, circular or more complicated cross sections. However, it is preferred that the elements do not exhibit right-angled or well-defined edges to allow a homogeneous metallization and to allow a continuous flow of the second transparent plastic material 17 essentially free of turbulence when melted or molded by injection. In the case of the trapezoid-shaped elements 4 of Figure 1, the radius of curvature at the upper edge and the lower part of the elements would be at least 0.2 millimeters and more preferably at least 0.5 millimeters.

The aesthetic appearance of the finely-developed decorative emblem can be varied widely by varying the geometrical shape of the elements 4, the radius of the elevations and voids and the average height of the elements 4 and the distribution of the heights of the elevations and voids, are preferred 3-dimensional designs which essentially comprise elevations.

The reference level of the front surface 2 of the substrate can be essentially flat as shown in the embodiments of Figure 1 and 2 or exhibit a curvature as shown in the embodiment of Figure 3 or other topography. In case the second transparent polymer 17 melts as a viscous, flowing material, the front surface is preferably essentially flat, while in the case of the injection molding of the second polymer 17 any topography of the front surface can be used. 2.

The substrate 1 comprises an edge or edges 22, which are preferably designed to provide a well-defined peripheral side of the cover or protective layer 18 of the second transparent polymer 17. In the event that the second transparent polymer 17 is melted as a viscous, fluent material, the edge preferably is a peripherally extending, vertically extending ridge 21. The resulting substrate is usually called a bevel 19 comprising a recess 20 surrounded by the dam 21. The recess 20 is shown in FIG. Figure 6. The supports of the dam control the flow of fluent plastic material 17 and the formation of a lens or curved surface externally of the protective cover. The curvature is generated by the surface tension of the second viscous, flowing transparent polymer 17 during dispersion. The recess 20 has a depth of typically from 1 to 6 millimeters.

It is also possible to use a well-defined edge or edges 22 if the second transparent polymer 17 is applied as a viscous flowable material as shown in the embodiment of Figure 2.

In case the second transparent polymer 17 is injection molded, any curvature of the outer surface of the cover 18 of the polymer 17 can be obtained by using a mold 11 with an appropriately formed internal surface 12. Figure 5 shows a mold 11, which is designed to create a lens-like cover 18 of the polymer 17. The injection molding of the cover or protective layer 18, therefore allows the design of the cover 18 to be varied widely and is preferred from a viewpoint aesthetic.

The substrates 1 comprising plastic materials are preferably obtained by injection molding or reaction injection molding using conventional techniques and processes described, for example, in Encyclopedia of Polymer Science and Ensineerins. New York, 1987, vol. 8, p. 102-158 and vol. 14, p. 22 ^ 100. The injection molding of thermoplastic polymers is preferred, therefore the plastic material is injected in molten form and subsequently solidified by cooling. Reaction injection molding (RIM) can also be used, for example, where solidification results from curing the precursor injected into the mold. The plastic-like substrates can be metallized or coated with metal, for example, with chromium or aluminum. Substrates comprising bulk metal can be obtained by conventional metal cutting technology, for example.

The rear surface 5 of the substrate 1 is preferably planar, but can also be designed to adapt in an orderly fashion to the surface to which it is attached.

In the next step b) of the method according to the invention, the substrate 1 is placed in the mold 6, therefore the internal surface 7 of the upper part of the mold 6 makes contact with at least a part of the surface 2 of the substrate to provide an opening 8, which is subsequently filled with the first plastic material 9. The opening 8 is preferably a closed cavity, but can be, for example, also laterally open to allow free peripheral flow of the first plastic material 9.

Figure 4 schematically shows this step of the method according to the invention for a bevel 19. The internal surface 7 of the upper part of the mold 6 closely makes contact with the edge 21 and the upper ends of the elements 4, so both provide a uniform opening throughout the gap 20 of the front surface 2, which is surrounded by the flange 21. The thickness of the opening in this mode is smaller than the height of the elements 4. The gap is shown, but it is not marked by a number in Figure 1.

The design of the internal surface 7 of the upper part of the mold 6, however, can be varied to allow a variation of the thickness of the opening on the front surface 2 of the substrate 1. The thickness of the opening can vary, for example, between the adjacent elements 4 of the design of 3 dimensions or even within a section defined by two adjacent elements 4.

In case the elements 4 are hollowed out, the average thickness of the opening preferably varies between 1/10 of the height and height of the openings and more preferably between 2/10 and half of the height of the openings. holes. If the elements 4 are elevations, the thickness of the opening 8 can exceed the height of the elevations and can vary, for example, between 1/10 of the height and twice the height of the elevations. The thickness of the opening 8 is preferably smaller than the height of the elevations and more preferably varies between 1/8 and 7/8 of the height of the elevations. The average thickness of the opening is preferably between 0.4 - 3 millimeters.

The method according to the present invention, therefore allows a wide variation of the 3-dimensional design of the substrate 1 and the 3-dimensional structure of the first plastic material, which can be used completely by the designer to create highly attractive decorative elements. aesthetically The opening 8 is filled with the first polymer material 9, which is injection molded via one or more conduits 10 extending from the front surface 2 to the outer surface of the bottom of the mold 6.

The term "first polymer or plastic material" refers to the polymer material which is filled in the opening 8 during step b) of the present invention. The first polymer material 9 may comprise one or more polymer compositions, which are injected simultaneously or subsequently to create multicolored decorative emblems.

The polymer compositions used for the first plastic material 9 preferably comprise one or more thermoplastic polymers such as, acrylonitrile-butadiene-styrene (ABS), acrylonitrile-styrene-rubber (ASA) copolymers, poly (meta) acrylates, or polyamides. The polymer compositions used for the first plastic material 9 can also be based on a reaction injection molding system (RIM) and comprises, for example, the curable precursor of an epoxy resin.

To create an aesthetically appealing decorative emblem, the polymer compositions used for the first plastic material preferably comprise dyes and / or pigments in an amount of up to 5% by weight with respect to the mass of the thermoplastic polymer or polymers. The amount of the dyes and / or pigments is preferably between 0.1 and 1% by weight. The addition of dyes and / or pigments, for example, can be omitted in case the substrate is colored and / or in case a specific design is obtained.

The first plastic material 9 may comprise other additives such as, for example, antioxidants, stabilizers or UV lubricants.

In case the first polymer material comprises only one polymer composition, it is preferably selected to exhibit an aesthetically attractive contrast with the 3-dimensional design of elements 4. The 3-dimensional design can be, for example, metallized and the first Polymer material comprises dyes and / or pigments. However, it is also possible that the substrate 1 with the 3-dimensional design comprises a colored polymer composition.

In case of multicolor designs, the first polymer material comprises at least two polymer compositions, which can be injected into an opening 8 simultaneously or subsequently. If they are filled simultaneously, the polymer compositions which are, for example, colored differently are combined or split before solidification or curing, thus creating a highly aesthetically appealing design.

It is also possible for a first polymer composition to be filled in a first opening 8, which is defined by a first internal surface 7 of the upper part of the mold 6.

Then the first polymer composition is solidified or cured and "then the substrate is expelled from the first mold 6 which is introduced into a second mold 6, the internal surface of which defines a second opening 8 which is then filled with the second polymer composition.

After curing and / or solidification of the second polymer composition, a third polymer composition can be injected and so on. This technique allows the preparation of multicolored 3-dimensional decorative elements, which are highly aesthetically attractive.

The number and positioning of conduits 10 depends on the number of polymer compositions that are injected. For each injection step, one or more conduits 10 are required. The number and positioning of the conduits for the individual injection passages is selected to provide a constant filling of the opening 8 which prevents the formation of turbulence or inclusions of air. The substrate may comprise channels connecting parts of the 3-dimensional design separated by the elements 4 to allow the flow of the first polymer material below the 3-dimensional design. Substrates having a maximum lateral extent of not more than about 10 centimeters and requiring a single color filling are preferably filled, for example, via one or more, preferably a conduit 10, while the process of preferably filled further is supported by channels. The person skilled in the art can design more complicated filling patterns in case of multicolored or larger decorative emblems.

The air displacing from the opening 8 can typically escape via the small opening between the inner surface 7 of the upper part of the mold 6 and the substrate 1 and the small opening between the lower and upper part of the mold 6, but it is also It is possible to provide a vent pipe that extends from the surface 2 of the substrate 1 to the external surface of the bottom part of the mold 6. The optional vent pipe is not shown in Figure 4.

The injection molding of a first thermoplastic polymer material 9 is preferred. The material 9 is injected under appropriate flow conditions to allow constant and uniform filling of the opening to avoid any inclusion of air and to prevent the polymer material from overflowing. the elements 4.

The temperature of the mold 6 is controlled to maintain the first injected polymer 9 in a fluid condition when the opening 8 is filled. The process parameters of the injection molding step mainly depend on the geometrical dimensions and the design of the mold and of the molds. properties of the first polymer material. The temperature of the mold 6 can often be chosen between 50 and 100 ° C and more preferably between 60 and 80 ° C. The viscosity of the first plastic material 9 is typically between about 10 and lxlO 4 Passes and more preferably between about 1x10 2 and lxlO 3 Pascals.

Although the mold 6 shown in Figure 4 comprises 2 rectangular parts with the substrate 1 which is completely placed in a half, it is not always necessary that the mold 6 has such a shape.

The diameter of the duct or conduits 10 and the injection pressure are selected to provide a constant and slow flow of the first injected plastic material 9 into the opening 8 to prevent the formation of. any of the inclusions and / or air turbulence. For substrates having a maximum lateral extent of not more than about 10 centimeters, the filling ratio is, for example, typically 100 cm3 / s or less and more preferably 50 cm3 / s or less.

The thermoplastic is melted by heating at temperatures of typically up to 260 ° C and more preferably between 200 and 250 ° C and is injection molded via conduits 10 in opening 8.

Then the plastic material 9 is solidified by cooling and the resulting article is expelled from the mold 6. During the cooling step, the shrinkage of the plastic material 9 is usually observed which, in particular, can result in breaks in the interface of the elements 4 and the first plastic material 9. The formation of ruptures is undesirable and can be suppressed by selecting first polymer materials 9 with a low shrink coefficient of preferably not greater than 0.6% volume. In addition, the shrinkage behavior of the first polymer material 9 can be advantageously influenced by applying a low cooling ratio. The cooling rate can be reduced by increasing the temperature of the mold. The formation of the ruptures can also be suppressed by increasing the pressure exerted on the article in the mold during the cooling step and / or increasing the diameter of the conduits 10.

After the article comprises the substrate 1 and the solidified layer of the first plastic material 9 has been expelled from the mold 6, the second plastic material 17 is applied to form a protective cover 18 covering the 3-dimensional design of elements 4 and the first plastic material 9. The term protective cover 18 indicates that the distance between the average upper end of the elevations of the 3-dimensional design and the outer surface of the protective cover 18 is preferably at least 1 millimeter and so more preferable at least 15 millimeters.

The second cured plastic material 17 is a transparent polymer that allows to observe the 3-dimensional design. It is preferably weather resistant and does not yellow or darken as a result of prolonged exposure to sunlight and detergent resistance. In addition, it is preferably resistant to abrasion and impact.

The second plastic material is preferably a one or multi-component polyurethane material which can be applied as a curable precursor with a subsequent cure by heating, UV radiation, RF heating or by drying in ambient air or as a polymer material fused with subsequent solidification by cooling. Many of the known polyurethanes derived from polyalcohols and polyisocyanates can be used in the present invention. Preferred are, for example, polyurethanes comprising the reaction product of polypropylene glycol and an aliphatic diisocyanate. Another preferred polyurethane is obtained as the reaction product of a polycaprolactam triol and an aliphatic diisocyanate-diol adduct of polycaprolactam. Furthermore, it is advantageous to use a polyurethane comprising the reaction product of (A) a mixture of polyester glycol and polypropylene triol having a low or medium molecular weight, and (B) a polypropylene triol of aliphatic diisocyanate added. In another preferred embodiment a flexible, relatively soft, weather-resistant polyurethane having a D Shore hardness in the range of about 10 to 80, more preferably 45-65, is used.

Other transparent materials, such as acrylic or epoxy resins, and mixtures such as polyurethane / acrylic resin blends and polyurethane / epoxy resin blends can also be used.

Other materials which are useful as the second plastic material are described, for example, in US Patent 4,708,894, US 4,139,654, US 4,566,929, US 4,767,642 or WO 94 / 13,497 and the references cited therein.

The second plastic material 17 can be applied as viscous, fluent, pourable material by coating, casting or spraying, for example. The viscosity of the precursor of the second plastic material is preferably no greater than 1,000 mPascals at 50 ° C.

The second viscous plastic material, fluent 17 so Preferably, it is applied with a dispersion device having holes 23, which are placed on the substrate to allow the formation of a uniform cover free of any of the air inclusions. Figure 6 shows a preferred arrangement of holes to provide a protective cover for an oval-shaped bevel 19 having a peripheral edge that extends vertically. The second viscous, fluent plastic material is melted via the holes 23 in the recess 20 of the bevel 19, which comprises a design of 3 dimensions of elements 4 that mark the word "Symbol" and is partially or completely covered between the elements 4 with the first plastic material 9.

Another suitable design of a dispersion device is described, for example, in US Pat. No. 4,356,617. The diameter of the holes and the dispersion speed are preferably selected to allow slow application of the protective cover of the polymer 17 to prevent turbulence of the flow and / or the formation of air inclusions. The time required to apply the protective cover is typically between 2 and 4 seconds.

The amount and viscosity of the second fluent viscous plastic material 17, the design of the dispersion device and the dispersion speed, the shape of the edge 22 of the substrate and the topography of the surface of the first plastic material are preferably selected so that the second material Cured polymer 17 forms a lens or curve shape on its external surface facing the inspector.

Figures 1 and 2 are schematic cross-sectional views of the preferred embodiments of the decorative emblems according to the invention, which are obtainable by applying a viscous, flowing polymer material 17. The decorative emblem of Figure 1 comprises a bevel 19 with a peripheral edge extending vertically, which supports the formation of the lens-shaped covers. The curvature is generated by the surface tension of the second viscous, flowing polymer material 17. As indicated in Figure 1, the layer connecting the top surfaces of the elements 4 of the 3-dimensional design can optionally be adjusted to the surface of the resulting lens-shaped cover. The decorative emblem of Figure 2 comprises well-defined edges 22, which support the formation of a cover that exhibits a curvature only at the edges, while the remaining regions of the surface of the cover are essentially flat.

The person skilled in the art can vary the parameters mainly that influence the shape and curvature of the cover of the second polymer material 17 to obtain a desired surface. The curvature of the cover is due to the inherent surface tensions in the second viscous, flowing plastic material 17. The curvature can also be provided or modified or the different surface topographies of the curvatures can be provided by post-machining of the transparent layer.

In an alternative preparation method which is preferred, the second plastic material 17 can also be applied via injection molding or reaction injection molding as shown schematically in Figure 5 for a bevel 19 comprising a peripheral rim that is vertically extends 21, the article comprising the bevel 19 and the solidified layer of the first plastic material 9, are introduced into a second mold 11 having an internal surface 12. The shape of the inner surface 12, which closely contacts the bevel 19 to provide a cavity 14, can be widely varied to provide cavities 14 and therefore covers of the second polymer 17 with different shapes. The second transparent material is injected via one or more conduits 23 extending from the surface of the bottom of the mold 11 to the surface 2 of the bevel above the surface of the first plastic material 9.

Depending on the nature of the second plastic material 17, it can be filled into the cavity 14 via injection molding or reaction injection molding.

Thermoplastic materials such as polyurethanes, polycarbonates or polyacrylates are preferably processed via injection molding. The temperature of the mold 11 is controlled to maintain the second injected polymer 17 in a fluid condition when the cavity 14 is filled. The process parameters of the injection molding step mainly depend on the geometrical dimensions and design of the mold and the molds. properties of the second polymer material 17. The temperature of the mold 11 is often chosen between 20 and 100 ° C. The viscosity of the second plastic material 17 is preferably between about 10 and lx104 Pascals and more preferably between about lx102 and lx103 Pascals.

The diameter of the conduit or conduits 23 and the injection pressure are selected to provide a constant or slow flow of the second injected plastic material 17 into the cavity 14 to prevent the formation of any of the air inclusions. The filling ratio is preferably 100 cm3 / s or less and more preferably 50 cm3 / s or less.

The second injected thermoplastic polymer 17 is solidified by cooling and the decorative emblem is expelled from the mold.

In the case of a second heat-set polymer material 17 such as epoxy resins, a curable precursor is injected into the mold 11. The temperature of the mold 11 is adjusted to allow curing of the curable precursor in typically 15-25 seconds. The viscosity of the curable resin is typically chosen between 1,000 - 5,000 mPascals. The decorative emblem is expelled from the mold after curing.

To join the decorative emblems according to the invention to a substrate it is usually required that the adhesive layer be applied to the back side 5 of the substrate 1 through other fixing means, in particular also particular mechanical fastening means can be used. In a preferred embodiment, the back side 5 of the substrate 1 is provided with an adhesive layer 25, which is protected by a release coater 26 as shown schematically in Figure 1. By removing the release coater 26, the layer is exposed. adhesive 26, so that the decorative emblem can adhere to the substrate or surface that is decorated.

The method for preparing decorative elements according to the present invention and the decorative elements obtained by such method exhibit several advantages: • The method of the present invention allows the preparation of decorative elements of a part, while the previous methods frequently require introducing a metal sheet embossed optionally in a bevel followed by the application of one or more polymers.

• The method according to the present invention provides an essentially non-limited design freedom. The designer can vary and adjust the 3-dimensional design of the substrate 1 and of the opening 8 which is filled with the first polymer material 9. He or she can select any desirable contrast between the substrate 1 and the first polymer material and create designs of one color or multicolored. This broad spectrum of design possibilities is not accessible in the prior art.

• In a preferred method of the present invention, the lens cover is obtained via injection molding, so that a wide variety of cover shapes can be obtained. The shape of the cover is obtained in a very reproducible way. The surface of the cover is typically very smooth, so post-machining is not required.

The method according to the invention can therefore be used to reproducibly prepare decorative, aesthetically attractive, 3-dimensional elements with an excellent surface finish. A preferred field of application for the 3-dimensional decorative elements is the automotive industry where, for example, the elongated fitting symbols or strips of the manufacturer on the sides of the automotive bodies can be decorative elements of the present invention..

It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects to which it relates.

Having described the invention as above, the content of the following is claimed as property.

Claims (9)

1. A method of preparing decorative emblems, characterized in that it comprises: (a) providing a rigid substrate having on the front surface a 3-dimensional design having elements, which form elevations or gaps with respect to the front surface, (b) placing the substrate in a first mold having an inner surface, which closely contacts a portion of the front surface to provide an opening between the inner surface and the recessed portions of the front surface, (c) injection molding a first plastic material through one or more conduits extending from the back surface of the substrate to the front surface to allow filling the opening with the first plastic material and solidifying or curing the first plastic material, (d) covering at least a part of the 3-dimensional design and the first plastic material with a second transparent plastic material to form a protective cover by means selected from: (i) placing the substrate in a second mold having a -surface internal, which closely makes contact with a part of the surface of the substrate, therefore provides a cavity in which the second plastic material is molded by injection through one or more ducts extending from the back surface to the surface frontal; and (ii) removing the substrate from the first mold and melting a measured amount of the second plastic material onto the first plastic material and the 3-dimensional design.

2. The method according to claim 1, characterized in that the substrate is a bevel having on the front surface a recess with the 3-dimensional design and a vertical rim surrounding the recess.

3. The method according to claim 1, characterized in that the substrate comprises materials, which are selected from the group consisting of metals, metal alloys and plastics selected from acrylonitrile-butadiene-styrene, acrylonitrile-styrene-rubber copolymers, polycarbonates, polyamides , epoxy resins and mixtures thereof.

4. The method according to claim 3, characterized in that the substrate comprises a plastic material, which is metallized before introducing the substrate into the mold.

5. The method according to claim 1, characterized in that the elements of the 3-dimensional design have an average height greater than the front surface of between 0.5 and 6 millimeters.

6. The method according to claim 1, characterized in that the first plastic material is selected from the group consisting of acrylonitrile-butadiene-styrene (ABS), acrylonitrile-styrene-rubber (ASA) compositions, poly (meta) acrylates, polyamides, and epoxy resins.

7. The method according to claim 1, characterized in that the second plastic material is selected from the group consisting of polyurethanes, polycarbonates, poly (meta) acrylates, epoxy resins and mixtures thereof.

8. The method according to claim 1, characterized in that a sufficient amount of the second transparent plastic material is used, such that in the finished decorative emblem the distance between the surface of the protective cover and the average upper end of the elements, which They protrude above the surface, it is at least 1 millimeter.

9. A decorative emblem obtained by the method according to claim 1.