MXPA06010019A - Composite part - Google Patents

Abstract

The invention relates to a composite part based on a sandwich structure at least comprised of:(a) two covering layers (3, 3') that, independent of one another, consist of at least one film, sheet, fiber mat and/or of a foam made of metal, plastic, glass, a natural substance and/or carbon, and;(b) a core layer (4), which is placed between the covering layers (3, 3') and which is made of metal, plastic, a natural material and/or paper having a multitude of cavities. A cast-resin system at least partially penetrates the covering layers (3, 3') and the core layer, and the covering layers (3, 3') are joined to the core layer (4) by pressing. The composite part is characterized in that the covering layers (3, 3') are pressed against one another at least in one area (5, 5') of the sandwich structure, and the sandwich structure is encapsulated by injection molding with thermoplastic material in the pressed area (5, 5').

Description

COMPOSITE COMPONENT FIELD OF THE INVENTION The invention relates to a composite component having an interleaved structure which consists of at least one core placed between two outer layers. A molten resin system penetrates into the layers at least in part, and the layers are joined together by pressure molding. The invention also relates to a process for the production of such a composite component. BACKGROUND OF THE INVENTION The light composite components having an interleaved structure, consisting of a core having a honeycomb or corrugated structure, made for example of paper, aluminum or plastic, and a lower and upper layer consisting of gratings of fibers made, for example, from natural fibers, glass, plastic or carbon, are known, for example, from EP 1 319 503. Due to their low weight per unit area and their high flexural strength with low wall thickness , they are used as interior trim in automotive construction, for example. The fiber grids constituting the lower and upper outer layers are wetted with a two component polyurethane (PU) system, for example, which partially or completely penetrates the core. The PU system, which can for example foam, REF: 175387 forms and joins the outer layers with the core. These interleaved composite components are manufactured by means of the compression molding process. The entire surface of both sides of the interleaved structure comprising core and outer layers is sprayed with the two-component PU system, and the structure is placed in the mold, which is generally heated from 60 to 160 ° C. , preferably 120 to 140 ° C, and is die cast. After being freed from the mold and cooled down, "the composite components can for example be drilled, machined or rolled, if required.The integration of screw connections, partial metal reinforcements, connecting elements, fasteners or the like, is only possible. For example, during the production of the composite component in the compression mold the inserts can be properly placed and adhered to the composite component by foaming and curing the PU system during pressure molding. the composite component by placing an outer layer, for example a fiber grid, on the upper part of the insert and pressing it on the insert during press molding.The solder connection to the light composite component of molded parts, made for example, is also known. However, this is relatively complex, given that the parts molded first have to be produced separately and then inserted into a welding tool for welding. In addition, the quality of the welded joint is very much dependent on the materials that are used. It is also known to encapsulate said composite components interspersed with freely flowing materials such as polyurethane. The disadvantage of these PU injection molded composite components is the relatively low stiffness and strength. In addition, selective injection molding of individual areas of the composite component with the PU crosslinking system of bonds is difficult. Burr formation in injection molded PU requires a costly secondary finish. Finally, an injection molded PU surface does not satisfy the optical requirements for certain applications and can not be pigmented. BRIEF DESCRIPTION OF THE INVENTION The object of the present invention, starting with the light composite components having an interleaved structure known from prior art, is to provide a composite component which is suitable for the integration of functional elements and molded parts, made of thermoplastic polymer in particular, by means of the molding or injection process. The invention provides a composite component based on an interleaved structure consisting of at least (a) two outer layers, each mutually independent consisting of at least one film, sheet, fiber grating and / or foam made of metal, plastic , glass, natural material and / or coal, and (b) a core placed between the outer layers, made of metal, plastic, natural material and / or paper that has a large number of cavities, where a fused resin system penetrates at least partially in the outer layers and the core, and the outer layers adhere to the core by pressure molding, characterized in that in at least one area of the interleaved structure the outer layers are pressed together and the compressed area of the interleaved structure It is encapsulated with thermoplastic polymer. The composite component according to the invention consists of at least three layers: a core and two outer layers, one on each side of the core. A structure comprising a multi-layer core and multi-layer outer layers is also possible. The core consists of metal, plastic, natural material and / or paper. The preferred metals are aluminum, magnesium, and alloys thereof. Preferred plastics are polyamide, polyester, polycarbonate, polypropylene, polystyrene, ABS, polyamide imide (PAI) and mixtures thereof. The plastics can be reinforced or not reinforced, filled or unfilled. Examples of natural materials are wood, linen, henequen, jute, hemp. Within the meaning of the present invention it is understood that paper is any type of paper, such as, for example, multilayer paper, for example, cardboard, or paper impregnated with resin.

As a substantial feature the core of the composite component according to the invention shows - a large number of cavities. The cavities can be of any geometric shape. They can be, for example, angular or round channels, pores or bubbles. The cavities can be arranged in a regular or irregular manner. The core preferably has a corrugated, angled, honeycomb or foam-like profile. The core may be, for example, corrugated metal or corrugated cardboard. Similar to a corrugated metal or corrugated cardboard, the core can also be angled instead of corrugated, for example, with a rectangular or triangular shape. In addition, similar to a corrugated metal or corrugated cardboard, the core can be made of plastic. An angled or corrugated plastic can, for example, be extruded. A multiwall sheet, for example, can be used as a plastic core. The thickness of the core is preferably in the range of 5 to 50 mm. Due to the large number of cavities the weight of the core is low in relation to its thickness. The density is preferably 10 to 1000 kg / m3.

The outer layers on each side of the core of the composite component according to the mutually independent invention consist of metal, plastic, glass, natural material and / or carbon. The outer layers are films, sheets, fiber grids and / or foams. Fiber grids can be for example meshes, woven fabrics, knitted fabrics, braided fabrics, non-woven fabrics or felts. The preferred metals for the outer layers are aluminum, magnesium, and alloys thereof. Preferred plastics are polyamide, polyester, polycarbonate, polypropylene, polystyrene, ABS, PAI and mixtures thereof. The natural materials for the outer layers may be, for example, flax, henequen, jute, and hemp. The outer layers on each side of the core 'may be the same or different. The thickness of the outer layers is preferably 0.1 to 2 mm. The weight per unit area of the outer layers is preferably from 225 to 1200 g / m 3. A molten resin system penetrates at least partially the outer layers and the core of the composite component according to the invention. This means that the cast resin system partially or completely fills the core cavities. In the same way the cast resin system penetrates the fibers and pores, the cavities or the like of the outer layers if they consist of fiber grids or foams. If the outer layers are films or sheets, the fused resin system is disposed between the outer layers and the core and partially or completely wet the outer layers. The molten resin system serves to bond the layers together, which are press molded under heat exposure before the molten resin system cures. In the case of fibrous outer layers, the fused resin system also fixes the fibers and forms the surface of the composite component. In particular, it gives the composite component a high strength and rigidity by adhering the layers together. This compound, which consists of at least one core, "two outer layers and a molten resin system, is known from the prior art. (for example, EP 1 319 503 A) and within the meaning of the present invention is also referred to below as an interleaved structure. The molten resin system can be a one-component or multi-component system, for example, a two component system. It can be foamed or not foamed. Examples of possible cast resin systems are: polyurethane (PU) systems, polyester resin systems, epoxy resin systems, acrylic resin systems. Preferably the two-component PU system is used, particularly preferably a two-component PU system as described in EP 1 319 503 A, page 2, line 26 to page 3, line 20. The weight per unit area of the cured two-component PU system is preferably 400 to 1200 kg / m2. The weight per unit area of the sandwich structure known from the prior art is preferably 2100 to 3600 g / m2. According to the invention, the outer layers are pressed together in at least one area of the interleaved structure of the composite component and the structure interleaved in the compressed area is encapsulated with thermoplastic polymer. Within the meaning of the present invention, pressing together the outer layers of the interleaved structure means that the interleaved structure is pressed together until the outer layers touch virtually one another. The core between the outer layers is compressed to a minimum in this process. The inter-layer pressure of the outer layers allows the thermoplastic polymer to adhere to the structure interspersed in the injection molding process. In the known sandwich structure of the prior art where the outer layers are not pressed together, the problem that occurs is that during the injection molding of the thermoplastic polymer on the interleaved structure the polymer is distributed uncontrolled inside the core due to the high injection pressure and as a consequence deforms or damages the interleaved structure. Since after pressing the outer layers according to the invention with one another the outer layers are placed virtually against one another, during the injection molding the molten plastic can no longer flow between the outer layers towards the interior of the core. Therefore, the pressure between them prevents the molten plastic from penetrating uncontrolled inside the core during injection molding and distorts or damages the core due to the high injection pressure necessary for handling the thermoplastic polymer. The pressure between the outer layers also prevents excessive uncontrolled spraying of the composite component, since the molten plastic can only penetrate into the injection mold cavity in the area where the outer layers are pressed together. In the other areas where the outer layers are not pressed together, the composite component is placed against the inner wall of the mold cavity, sealing the mold cavity against uncontrolled dispersion of the molten plastic. The outer layers can be pressed together in an edge area of the interleaved structure of the composite component, for example, and encapsulated with thermoplastic polymer. The interleaved structure can therefore be provided with a partial or continuous encapsulated edge of thermoplastic polymer. The outer layers of the composite component can also be pressed together during production in any other area, however, depending on which area the composite component is thermoplastic polymer encapsulated. For example, if the composite component has openings, the edges of the openings, for example, can be compressed and encapsulated with thermoplastic polymer. Protuberances and other deformations on the surface of the composite component can also be compressed and encapsulated with polymer. On the other hand, it is possible to deliberately allow the molten plastic to enter the core or an area of the composite component, creating a biased cut and therefore a positive bond between the interleaved structure and the thermoplastic polymer. This can be done for example by pressing together the outer layers of the composite component at a certain distance from the edge of the sandwich structure or from an opening, for example, in an annular shape around the opening. During injection molding the open edge of the opening, that is, without compressing. However, due to the compression, the molten plastic can not be distributed uncontrollably inside the core but only at most up to the compressed area, for example, around the opening. The thermoplastic polymer with which the interleaved structure is encapsulated by injection molding is preferably a non-reinforced, reinforced and / or filled polymer based on polyamide (PA), polyester, particularly polyethylene terephthalate (PET, for its acronym in English), polybutylene terephthalate (PBT), polystyrene (PS), acrylonitrile-butadiene-styrene (ABS), thermoplastic polyurethane (TPU), for its acronym in English), polyolefin, in particular - polypropylene (PP), polyethylene (PE), polycarbonate (PC), polypropylene oxide (PPO, for its acronym in English), polysulfone (PSO), polyphenylene sulfide ( PPS, polyimide (Pl), polyether ether ketone (PEEK) or a mixture of these polymers. The encapsulation of the interleaved structure, consisting of a core and outer layers with a molten resin system, with thermoplastic polymer allows the rigidity and strength of the interleaved structure to be increased. In addition, functional elements such as reinforcing, stiffening or joining elements can be injection molded onto the interleaved structure at any point, for example at the edge or on the surface, in a variety of ways. In this way the molded parts or components made of other materials, for example metal, can be attached relatively easily to the composite component according to the invention. In this way it is possible to integrate the composite component according to the invention relatively easily into a global system comprising several identical or different molded parts or components. Various molded parts in the style of the molded component according to the invention can also be joined together in this manner. The invention also provides a process for the production of the composite component according to the invention, the process is characterized by the following steps: (i) inserting the core and the outer layers in a compression mold, placing the core between the outer layers (ii) applying the molten resin system to at least one of the outer layers, steps (i) and (ii) being carried out in any order, (iii) pressurizing the core with the outer layers to form the interleaved structure and pressing the outer layers together in at least one area of the interleaved structure, (iv) removing from the mold the interleaved press-molded structure in accordance with step (iii), (v) inserting the interleaved structure press-molded into a Injection mold and injection molded thermoplastic polymer on the structure interleaved in the area in which the layers have been pressed together.

The prior art known structure of the composite component according to the invention is produced by means of the compression molding process, ie the outer layers are joined to the core by pressure molding, in particular full pressure molding (in the present stage (iii)). Prior to injection molding, the molten resin system is applied in the liquid state to at least one outer layer, in particular to its entire surface (stage (ii)). The molten resin system can be applied, for example, by spraying. The application of the fused resin system (step (ii)) can take place inside the compression mold after inserting the outer layers and the core (step (i)) or outside the compression mold before inserting the outer layers and the core. In the compression mold the core is placed between the outer layers (step (i)) and then molded under pressure (step (iii)). The performance of the process is described, for example, in EP 1 319 503 A. Before the fused resin system cures, the outer layers of the interleaved structure according to the invention are pressed together in a desired area, for example , in the edge area (stage (iii)). The injection molding of the core with the outer layers to join the layers together and press the outer layers together in selected areas takes place in a compression mold simultaneously or successively. The pressing of the outer layers with one another advantageously takes place in the same compression mold as the compression molding of the outer layers and the core to produce the sandwich structure itself. However, in principle, it is also possible for the two secondary stages to be carried out successively in different compression molds. After curing, optional cooling and mold release (step (iv)), the press-molded interleaved structure is placed in an injection molding and encapsulated with thermoplastic polymer in the injection mold in the areas in which the outer layers have been pressed together (stage (v)). The composite component according to the invention can be used for example in the automotive construction for door cladding elements, vehicle floors, instrument panels, instrument panel supports and horizontal parts of the body, but also for furniture elements or appliances. The injection molded thermoplastic polymer on the press molded structure can be a functional element, for example, a reinforcing rib. BRIEF DESCRIPTION OF THE INVENTION The invention is explained in more detail with reference to the appended figures. Figure 1 shows a cross section of a section of the composite component according to the invention in the injection mold after the injection molding of the thermoplastic polymer in a compressed edge area. Figure 2 shows a schematic cross section of a section of the composite component according to the invention in the injection mold after the injection molding of the thermoplastic polymer in a compressed edge area, penetrating the polymer inside the core in an uncompressed area . Figure 3 shows a schematic cross section of the composite component according to the invention in the injection mold after the injection molding of the thermoplastic polymer in the area of an opening compressed in the composite component. DETAILED DESCRIPTION OF THE INVENTION Figure 1 of the composite component 1 is placed between the two mold halves 2, 2 'of the injection mold (not shown). The composite component 1 consists of two external layers 3, 3 'and a core 4 having, for example, a honeycomb structure. The core 4 is placed between the two outer layers 3, 3 A In the embodiment of the composite component 1 shown in Figure 1 the outer layers 3, 3 'have been pressed together in their edge area 5, 5' in such a way that the outer layers 3, 3 'are placed virtually against each other. The core 4 placed between the outer layers 3, 3 'is virtually completely compressed in the compressed edge area 5, 5 A In the compressed edge area 5, 5' the composite component 1 is encapsulated with the thermoplastic polymer 6. The The thermoplastic polymer 6 does not penetrate into the core 4 of the composite component 1 between the outer layers 3, 3 'which have been pressed together. In contrast to the embodiment shown in Figure 1, in the embodiment illustrated in Figure 2 the two outer layers 3, 3 'are not pressed together directly in the edge area 10, 10 A but in an area 9, 9. ', which is some distance from the edge 10, 10 A During the injection molding of the thermoplastic polymer 6 on the composite component 1, the thermoplastic polymer 6 penetrates into the core 4, ie, between the outer layers 3, 3 A in the non-compressed edge area 10, 10 A The thermoplastic polymer 6 penetrates within the core 4 to the compressed area 9, 9 A The injection molded polymer 6 then forms a skewed cut. In the area 9, 9 'where the outer layers 3, 3' have been pressed together, the polymer 6 no longer penetrates into the core 4. The compressed area 9, 9 'prevents further, in particular uncontrolled, distribution of the molten polymer 6 inside the core 4. Figure 3 shows an additional embodiment of the composite component 1, which is placed between two mold halves 2, 2 'of the injection mold (not shown). The outer layers 3, 3 'show superimposed openings 7, 1'. The core similarly shows an opening 11 in the area of the superimposed openings 7, 7 A The outer layers 3, 3 'are pressed together at their perimeter edges 8, 8' of the openings 7, 7 A The superimposed openings 7, 7 11 are encapsulated with thermoplastic polymer in such a way that the polymer 6 forms a positive bond with the composite component 1. In another embodiment, which is not shown, it is also possible to make an opening, for example, in the encapsulated thermoplastic polymer. . EXAMPLE The interleaved structure was formed from a paper honeycomb of 6 mm thickness with a weight per unit area of approximately 1000 g / m2 as a core and two fiberglass grids each with a weight per unit area of approximately 400 g / m2 on each side of the core. The layers were bonded together with a fused polyurethane resin system comprising polyol and diisocyanate (Baypreg F®, Bayer AG, Germany) with a weight per unit area of approximately 400 g / m 2 by injection molding in a mold of compression. The weight per unit area of the interleaved structure produced in this way was 2630 g / m2 (density 0.4 g / cm3). At the same time that the layers were compression molded in the compression mold, ie, in a single process step, the outer layers of the interleaved structure were pressed together in their outer edge area prior to curing the system. 'molten polyurethane resin. After curing the PU resin the molded part was removed from the mold and placed in an injection mold. In the compressed edge area, polyamide 6 GF 30 was injection molded onto the structure interspersed in the injection mold. The thickness of the injection molded plastic was 6 mm. The overall thickness of the composite component was 6 mm, the density was approximately 0.7 g / cm 3, the weight per unit area was approximately 4400 g / m2. The injection molded thermoplastic polymer did not penetrate into the core between the outer layers. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention is that which is clear from the present description of the invention.

Claims (9)

1. CLAIMS Having described the invention as above, the content of the following claims is claimed as property: 1. A composite component based on an interleaved structure, consisting at least of: (a) two outer layers, each mutually independent consisting of at least one film, - sheet, fiber grating and / or foam made of metal, - 'plastic, glass, natural material and / or coal, and (b) a core placed between the outer layers, made of metal, plastic, natural material and / or paper that has a large number of cavities, where a system of Molten resin penetrates at least partially in the outer layers and the core, and the outer layers adhere to the core by pressure molding, characterized in that in at least one area of the interleaved structure the outer layers are pressed together and the compressed area the interleaved structure is encapsulated with thermoplastic polymer.
2. 2. A composite component according to claim 1, characterized in that the core has a corrugated, angled, honeycomb or foamed structure.
3. 3. A composite component according to one of claims 1 or 2, characterized in that the outer layers are fiber grids.
4. 4. A composite component according to one of claims 1 to 3, characterized in that the molten resin system is a two component polyurethane system. A composite component according to one of claims 1 to 4, characterized in that the outer layers are pressed together in the edge area of the interleaved structure and the compressed edge area is encapsulated with thermoplastic polymer. 6. A composite component according to one of claims 1 to 5, characterized in that the outer layers are pressed together in the area of an opening, a protrusion or deformation in the interleaved structure and the compressed area is encapsulated with the polymer. thermoplastic A composite component according to one of the claims 1 to 6, characterized in that the encapsulated thermoplastic polymer near the area of the outer layers has been pressed together at least partially the cavities in the core in such a way that it forms a cut biased A composite component according to one of claims 1 to 7, characterized in that the thermoplastic polymer is a non-reinforced, reinforced and / or filled polymer based on polyamide (PA), polyester, particularly polyethylene terephthalate (PET), terephthalate of polybutylene (PBT), polystyrene (PS), acrylonitrile-butadiene-styrene (ABS), thermoplastic polyurethane (TPU), polyolefin, in particular polypropylene (PP), polyethylene (PE), polycarbonate (PC), polypropylene oxide (PPO), polysulfone (PSO), polyphenylene sulfide (PPS, for its acronym in English), polyimide (Pl), polyether ether ketone (PEEK) or a mixture of these polymers. 9. Process for the production of a composite component according to one of claims 1 to 8, characterized by comprising the following steps: (i) inserting the core and the outer layers in a compression mold, placing the core between the layers external, (ii) applying the molten resin system to at least one of the outer layers, carrying out steps (i) and (ii) in any order, (iii) pressurizing the core with the outer layers to form the structure interleaving and pressing the outer layers together in at least one area of the interleaved structure, (iv) removing from the mold the interleaved press-molded structure in accordance with step (iii), (v) inserting the interleaved structure press-fit into an injection mold • and injection molded polymer • thermoplastic on the structure interleaved in the area in which the layers have been pressed together.