Manufacture process for a decorated trim part

The present invention relates to a trim component for an automobile interior, which is composed of a base material and a foil bonded thereto.

Automotive interior trims are currently composed of a wide variety of articles composed of substrates that provide adequate dimensional stability for the article and absorb the mechanical forces generated. This substrate has often been covered with foil to improve the visual appearance quality of the interior of the vehicle. This foil was previously often a relatively thick "in-mold decoration" (IMD) foil, but it is relatively expensive and / or not very scratch resistant and / or very Is glossy (as measured by VDA Standard 621-409, for example, it has a gloss level of greater than 10 or greater than 20 or greater than 30).

Therefore, an object of the present invention is to provide a trim component that does not have the drawbacks of the prior art for the interior of an automobile.

This purpose is achieved by using trim parts for the interior of an automobile, which consist of a substrate and foil attached to it. However, the foil is composed of polypropylene (PP) or polypropylene copolymer.

It was extremely surprising and unexpected to those skilled in the art that the trim parts according to the present invention could be manufactured and processed at a relatively low cost. The trim component according to the present invention has high scratch resistance and can be provided with a wide variety of decorative effects.

According to the present invention, the molded article or substrate has at least one surface covered with foil. The foil or coated foil used herein includes foils that are at most 500 μm thick. The thickness of the foil layer is preferably less than 500 μm, particularly preferably less than 400 μm or about 400 μm, particularly preferably less than 300 μm or about 300 μm, or in the range of about 300 μm to about 400 μm. This allows for significant cost savings across components as much less material is used for the foil and lower cost materials and / or manufacturing processes are used for the foil. Become.

According to the present invention, it is particularly preferable that the foil has a coating pre-applied to the foil or a coating layer pre-applied to the foil on a surface (visual surface) facing away from the substrate. In this way, the appearance of the trim parts on the foil-laminated surface (visual surface) is particularly easily changeable and can be adjusted by changing or adjusting the coating or coating layer. ..

According to the present invention, the thickness of the coating layer is more preferably about 1 μm to about 30 μm, preferably about 5 μm to about 20 μm, particularly preferably about 10 μm, or preferably up to about 10 μm. The remaining thickness of the foil is preferably slightly thinner than 300 μm (if the overall thickness of the foil is, for example 300 μm) to slightly thinner than 400 μm (the overall thickness of the foil, (For example, 400 μm), preferably formed by a multilayer foil structure, i.e., a foil structure having at least one layer and one additional layer. As another option, the foil can be a so-called monofoil. That means that the foil contains only one layer (which can be composed of multiple materials). The term monofoil also includes such foils, even if they contain multiple layers, as long as these layers have the same material composition.

When manufacturing finished trim parts, especially automotive trim parts, the foil is bonded to a plastic backing or substrate, including a coating. One of the methods available in this case is to insert the foil together with the coating layer in the form of a sheet (ie, in a flat state) into a molding die for the manufacture of trim parts, and then a plastic material for the manufacture of the substrate. In a single manufacturing process of injection, the foil is also molded along with the coating layer as well as the plastic backing, and in this molding process, on the visual surface of the coating or on the visual surface of the foil, the so-called grain. Are generated at the same time. This grain is commonly associated with a height difference of about 0 μm to about 300-400 μm on the visual surface of the surface of the trim component. As an alternative to this manufacturing procedure, which uses a single molding process that not only shapes the foil but also the plastic backing, according to the invention, the foil is pre-prepared with the coating in the first molding process. It is possible to mold and not bond to the plastic material of the plastic backing until the second molding process (in the second molding) is reached. The manufacturing process is always the so-called in-mold graining process (IMG process), which allows (but is not necessary) to introduce grains into the coating or foil layer of the trim parts. This process can be either an injection molding process or another transfer molding process.

If the foil is flat and is directly converted to the final shape, it is possible to start heating the foil prior to the molding process so that the molding of the foil is easier. A substantial advantage of the present invention is that the foil does not break when the foil material is integrated with the substrate material. Nevertheless, the foil must have a type of moldability that also fits into the fine features of the molding structure. Specifically, due to the thin thickness of the foil, during injection molding, during the introduction or molding of a plastic material for backing (which is a liquid, its temperature is, for example, about 270 ° C). It is important to avoid damage. If the foil is thermoformed (ie preformed) in the first step and not converted to the final shape until it reaches the second molding step, which is integrated with the backing plastic material, it is generally the second molding. The heating of the foil is not started before the process. Nevertheless, again, care must be taken to ensure sufficient foil stability, especially when integrated with the backing material (which is specifically under pressure at high temperatures). .. When the thermoforming procedure is performed in the first step of the process, the molding performed is generally about 95% of the final molding degree.

When molding a foil in one step, trimming or edging is generally performed after the molding process. In this case, after the molding step, there can be a step of cutting the foil, or the foil can be edge folded. In the case of a two-step manufacturing process (thermoforming the foil in the first step of the process), the present invention performs a foil stamping or cutting step between the first and second molding steps. It is possible. In this case, it is not necessary to perform downstream machining of the component after the second molding step. However, it is also possible to delay the cutting or stamping step and perform it after the second molding step.

The mold release of the finished trim part with the foil coupled on the visual plane is performed using known techniques in any of the molding steps.

According to the present invention, it is possible to use a plurality of material systems or combinations of material systems for (vehicle) trim parts. In the first combination of materials, the coating or coating layer provided on the visual plane of the foil is a polyurethane coating, the multilayer foil is a polypropylene copolymer multilayer foil, and the plastic backing is a polypropylene plastic backing, suitable. If so, it may include a filler or reinforcing material such as fiber, in which case the plastic backing may be foamed. In other combinations of materials for vehicle trim parts, the coating layer is also a polyurethane coating layer and the foil is also a polypropylene copolymer multilayer foil, which contains certain adhesion promoters and of plastic backing. The plastic material is ABS and / or PC material (ABS = acrylonitrile-butadiene-styrene, PC = polycarbonate). In this case, the backing material composed of polypropylene plastic and the backing material composed of ABS or PC plastic are both commercially available plastic materials containing, for example, up to 30% fiberglass and / or up to 30% talc. Any of these additive materials may be added up to 50% in theory, with the actual plastic content (ie, polypropylene content in the case of polypropylene-based plastic backing, or ABS and / or PC. ABS / PC content in the case of plastic backing based on is always at least 50%.

Therefore, according to the present invention, the provided coating layer is based on polyurethane and preferably contains a thermoplastic material system or a reactive two-component polyurethane system, or the coating layer has high scratch resistance and / or high scratch resistance. It has chemical and / or high UV resistance and / or high writing resistance, or the coating layer is visually recognized as a matte surface (a surface with a certain gloss level in the sense of relatively low gloss), and further. Preferably feels soft to the touch. In this case, the gloss is measured according to, for example, VDA621-409, and according to the present invention, a gloss level of 0.5 or greater, in particular a gloss level of about 0.5 to about 1.5 or about 0.5 to about 4.0. Gloss level or about 1.5 ~ about 4. A gloss level of 0 is achievable. In this case, the scratch resistance is determined using, for example, a so-called Erichsen pen, and according to the present invention, scratch resistance up to a load of 20 N can be achieved. Alternatively, scratch resistance is tested, for example, by the so-called grid method using so-called ΔL value color measurements (eg, under loads of 5N, 10N, and 15N). Alternatively, scratch resistance is determined by a so-called five-finger test (using pens with different loads from 2N to 25N) or according to the manufacturer's standard BMW PA0015 or PA0016. According to the present invention, the force that can be tolerated (no visual surface damage when applied) is up to 7N, otherwise up to 15N. According to the present invention, write resistance is determined according to, for example, one of the manufacturer's standards GM9150P (General Motors) or LP-463 / PB-5401 (Chrysler). Will be done. In this case, chemical resistance is generally measured according to various manufacturer standards, specifically for gasoline, isopropanol, methanol, and some commercially available "automotive cleaners". Conventional chemical resistance. According to the present invention, the surface gloss level of the finished trim component is less than about 1.5 (eg, VDA621-409 compliant), and the surface scratch resistance is at least about 10N (eg, the test methods listed above). It is particularly preferable that it is measured by one of them).

The foil is a monolayer foil (eg, a polypropylene-based monofoil, the manufacture of which specifically requires a single layer foil consistently or makes foil from multiple (similar) layers. (Need to do) or otherwise multi-layer foil (in this last case, means that the foil has at least one layer and one additional layer (different layers), in total, For example, it can have 3 or 5 layers (excluding the outer coating layer). However, at least one layer is composed of polypropylene. The additional layer preferably comprises a thermoplastic material, particularly preferably polystyrene (PS) or PS copolymer, polyolefin, polyolefin copolymer, or thermoplastic elastomer (TPE). Preferred thermoplastic elastomers are based on styrene copolymer components, thermoplastic elastomers (TPES), ethylene / propylene tarpolymer / propylene thermoplastic elastomers (TPEV), copolyester thermoplastic elastomers (TPEE), or polyurethanes. Thermoplastic elastomer (TPEU). The additional layer most preferably comprises a combination composed of at least two of the above-mentioned thermoplastic materials and / or thermoplastic elastomers.

Foil is specifically (but not always) composed of an outer layer composed of polyethylene terephthalate (PET), polymethylmethacrylate (PMMA), or polycarbonate (PC), or at least two of these components. It has an outer layer composed of the mixed mixture.

Each layer of foil can be bonded during co-extrusion via a suitable adhesion promoter layer. Another alternative option is to use an adhesive to laminate and integrate them.

The foil preferably has a decorative layer, which is particularly preferably applied by the printing process.

A particularly preferred embodiment of the foil comprises polypropylene, specifically PPH (polypropylene homopolymer) or PP copolymer. Polypropylene block copolymers with relatively low melt index (MFI, melt flow index) less than 1 g / 10 min (230 ° C / 2.16 kg) to achieve particularly good stability during injection molding in-mold coating. (PPBC) is used in at least one layer or one additional layer. Furthermore, some elastic materials have a content of less than 30%, which gives the foil moldability or extensibility. For this purpose, for example, thermoplastic elastomers are used. The foil may further contain small amounts (usually less than 15%) of additives such as color pigments, fillers, stabilizers, process aids and the like.

Especially in the manufacture of foils, the so-called sleeve process is used for polishing the foils. In this process, the required Class A surface is obtained by passing the polymer melt between the metal belt and the cooling roll after discharge from the flat film die. Substantially the surface of the foil determines the appearance quality of the coating layer applied to the foil. In addition, since the orientation level is low and the crystallinity is low, this method improves the mechanical properties. In particular, this method improves thermoformability or formability and imparts greater toughness to the foil.

The base material of the molded article according to the present invention preferably includes a thermoplastic material processed in the form of a melt, or an alternative thermoplastic material in the form of a mat.

Materials processed in the form of melts are polypropylene (PP), acrylonitrile / butadiene / styrene (ABS), a mixture of ABS and polycarbonate (PC), polyamide (PA), or thermoplastic elastomer (TPE). It is preferably composed of or containing a thermoplastic elastomer based on natural rubber and / or polypropylene (PP). In addition, the material processed in the form of a melt is preferably composed of a mixture composed of at least two of these materials.

The material processed in the form of a melt is particularly preferably containing a filler. Examples of fillers are talc, chalk, and wollastonite. In addition, the material processed in the form of a melt is a reinforcing material, for example, glass fiber, natural fiber, carbon fiber, or textile type reinforcing material, for example, glass fiber, for the purpose of improving its mechanical stability. May include mats or natural fiber mats. Also preferably, other materials added to the material processed in the form of a melt are pore-forming agents, such as physical or chemical foaming agents, or gas-supported elastomer beads.

Thermoplastic materials in the form of mats preferably include fibers such as natural fibers, glass fibers, or carbon fibers and thermoplastic binders such as polypropylene. The thermoplastic binder can be mixed with the other fiber in the form of fiber or powder.

The trim component according to the present invention is manufactured by in-mold coating of a thermoplastic material, for example, using an injection molding method, a compression molding method, or an injection compression molding method. In-mold coating by injection molding is preferably performed in the same manner as in DE 10 2005 039 600 (as a result incorporated herein by reference).

Before binding to the foil, preferably the substrate in the form of a mat is preheated and then bonded to the foil in the molding mold by compression molding or injection compression molding.

In some cases, the foil is preheated, preferably as a 2D foil, or the foil is preformed, for example by thermoforming, and then placed in a molding mold, eg, injection molding, compression molding, or. Using the injection compression molding method, it is bonded to the base material in the molding mold by in-mold coating. Prior to inserting the foil into the molding die, if appropriate, cutting, eg stamping, is performed to give a suitable outer shape.

It is possible to generate the surface structure of the trim component according to the present invention through an appropriate surface of the molding mold. It can have either a polished surface or a textured surface, so it is possible to produce trim parts with smooth or grainy grained surfaces.