WO2000071341A2 - Application technique - Google Patents

Abstract

The invention relates to an application technique for producing moulded part F, comprising the following steps: in-mould injection moulding, in-mould compression moulding or compression moulding of a support layer (1b) which consists of a foamed material, to form a moulded body (1); application of an adhesive layer (2) to the free surface of the support layer (1b) and gluing of a decorative element (3), preferably consisting of leather, to the latter. The method enables a soft-touch effect to be created in a simple manner for moulded parts F which comprise a decorative surface.

Description

 LAMINATING PROCESS

The invention relates to a lamination process for the production of molded parts with a decorative surface, in particular for vehicle interiors, by gluing a molded body having a plastic base body with a decor, a molded body having a support layer having a free surface in the lamination area by means of a direct process, for example by means of rear pressing , Injection molding, compression molding or the like. Made, an adhesive layer is applied to the free surface of the base layer and a decor is pressed onto the surface of the base layer, and preferably leather, velor fabric or flat weave is used as the material for the decor.

The technique of lamination is a process in which a covering material, for example leather, velor, fabric, etc., is applied to a molded part, usually made of plastic, to increase its decorative appearance. In known laminating processes, the adhesive is applied to the plastic side of the molding and the decor is pressed on. Despite applying the adhesive as evenly as possible, problem areas such as edges, beads, etc. can lead to undesired detachment of the decor from the molded body, especially if the decorated surface is exposed to high climatic stress, as is particularly the case in vehicle interiors.

Some plastics such as ABS (Acrylonitrile-Butadiene-Styrene) or ABS-PC (Acrylonitrile-Butadiene-Styrene Polycarbonate) can be glued directly. Other plastics have to be pretreated. For example, the surface of the molded body is loosened or roughened by organic solvents, which results in better adhesion of the decor, but requires an additional work step. For geometrically sophisticated parts Additional work step required However, detachment occurs repeatedly with geometrically sophisticated parts.Until now, polypropylene could not be used for laminating due to its surface properties and the associated high risk of the decor becoming detached, although this material would be particularly interesting from ecological and economic considerations because it is environmentally friendly and inexpensive to manufacture

EP 0 715 970 A2 discloses a lamination process for the production of molded parts with a decorative surface, in particular for vehicle interiors, a molded body with a free non-woven surface being produced in the lamination area by means of a direct process and an adhesive being applied to the non-woven surface of the Vhesform body. A decor is then applied pressed onto the nonwoven, leather, woolen velor or flat weave is preferably used as the decoration. The term direct process (one-step process or in-mold decoration process) includes shaping processes for plastic parts, such as back pressing, back molding, press molds or the like understand which include only a single step

In the lamination process described in EP 0 715 970 A2, the decor is glued to the bound nonwoven surface of the plastic molded part. Without using an additional flexible intermediate layer, a relatively hard, unyielding surface is created

Particularly in the case of vehicle interiors, however, a compliant and soft surface with a so-called soft-touch effect is sometimes desired. In order to achieve such a soft-touch effect, it is known to glue the leather with an intermediate foam layer and to cover the foam surface of the leather. Gluing the foam part to the free non-woven surface of a molded article This laminating process, which essentially consists of three work steps, is relatively complex and requires the use of a non-woven material which is treated in the direct process

No. 4,721,642 A describes a molded part with a decorative surface, which has a molded body produced by a direct process with a free non-woven surface has, on which an adhesive layer is applied. A pile of a multitude of colored polyamide fibers is applied to this adhesive layer in such a way that one end of the fibers adheres to the adhesive layer. Finally, a covering layer made of foamed polyurethane resin is applied to the pile. The fabrication of the pile and cover layers is in any case relatively complex and has numerous intermediate steps.

US 3,713,936 A describes a molded part with a thermoplastic lower layer, an inner layer made of one or more mats made of cotton wool and a fabric layer. The inner layer made of cotton is connected to the fabric layer by gluing. Then a low-melting thermoplastic material is applied to the other side of the cotton layer, the raw molded part is heated and placed in a mold, the molded part taking on its corresponding shape through melting and solidification of the thermoplastic material. This manufacturing process is also relatively complex and has many intermediate steps.

From US 4,581,272 A a molded part for a vehicle door with an outer textile fabric layer is known, which has fiber loops, the ends of which are embedded in a substrate layer with thermoplastic fibers. The fabric layer is fused to the substrate layer by melting the thermoplastic fibers under the action of pressure and heat.

Furthermore, US Pat. No. 4,445,954 A describes a production method for upholstered decorative linings for vehicle interiors with a decorative one

Described fabric surface and a padding made of polymer foam. The cladding has a first and a second carrier layer made of thermoplastic fibers, which are arranged on both sides of a core of non-woven synthetic fibers and are connected to this. Furthermore, the cladding has an intermediate layer made of thermoplastic polymer foam and an outer surface layer made of a decorative, padded material. The intermediate layer and the surface layer are placed on top of one another, connected to one another and placed in a heatable mold. The two carrier layers and the core are then heated in order to melt the thermoplastic fibers and then placed in the mold on the polymer foam intermediate layer. The entire assembly is heated and pressed in the mold, connecting the surface layer to the base layer. After the cladding has cooled, it has the appropriate shape. This manufacturing process is also very complicated.

The object of the invention is to avoid these disadvantages and to develop a simple laminating process for molded parts with a so-called soft-touch effect, in which a firm adhesion of the decor to the substrate is ensured even under high climatic conditions.

According to the invention this is achieved in that a foam is used for the base layer.

So far it has been assumed that in order to achieve a soft touch effect for a decor, a foam intermediate layer is glued to the decor and the decorative foam composite has to be glued to a separately produced nonwoven molded body in order to achieve a firm connection between the decor and the nonwoven molded body. It has now been shown that the foam can be connected to the plastic base body 1a in a direct process during the production thereof. The foam can thus take on the function of a base layer for the direct process.

A molded body, which has a foam layer, is thus first produced by one of the known direct processes for the production of molded plastic parts and finally, in a further manufacturing step, the decor is pressed onto the foam side of the molded body. In comparison with known lamination processes for molded parts with a decorative surface that has a soft-touch effect, the proposed lamination process is much simpler and essentially only has two process steps. The adhesive can adhere to the large and rough surface of the

Foam, which preferably consists of polyurethane, polyolefin, polyvinyl chloride, polyether or polyester, combine excellently, so that a very good cohesion between the molded body and the decor is made possible. From a technical and commercial point of view, it is with the method according to the invention It is particularly advantageous that the production of both decorated and undecorated, that is to say laminated, molded parts is possible in the same tool. In addition to saving costs by eliminating the need for an additional tool, this also increases production flexibility. Molded parts with a wide variety of decorative surfaces can thus be produced in one tool.

The component produced, for example an interior trim part for a motor vehicle, can be processed particularly cleanly at transition and edge areas, since any protruding foam can be removed here before lamination with the decorative material. A fold can therefore only be formed by the decorative material. This is not possible in the known version, where a decorative foam composite is used.

In principle, any thermoplastically processable injection molding material, such as ABS or ABS-PC, can be used as the plastic for the direct process. However, the adhesion of the adhesive and thus the decoration to the foam is so high according to the method according to the invention that even polypropylene can be used. Thus, the lamination is extremely inexpensive to manufacture and allows environmentally friendly production. As with all other thermoplastic materials, the recycling of old products is unproblematic due to the polypropylene content.

In a preferred embodiment, a foam is used which is provided on at least one side with a fleece lamination, to which the plastic forming the base body is applied in a direct process. The fleece lamination permits the use of foams which are more sensitive to heat without the risk of damage during the production of the molded body 1.

When using certain types of adhesive, it is also advantageous if the second side of the foam is also provided with a fleece lamination.

All common adhesive systems such as hot melt, dispersion solvent-containing adhesives or two-component adhesives can be used as adhesives in the process according to the invention be used. In principle, any type of decor can be used, but the best results can be achieved with leather, suede or flat fabrics.

The figure schematically shows an embodiment of a molded part F according to the invention. As shown in the figure, the molded body 1 of the molded part F consists of a plastic base body 1a, which is firmly connected to a support layer 1b made of foam. A decor 3 is firmly connected to the base layer 1 b of the molded body 1 via an adhesive layer 2.

The foam can be laminated with a non-woven layer at least on one side. This fleece layer is located between the foam and the plastic base body, so that it forms a firm connection with the carrier layer via the fleece layer during its manufacturing process. A foam provided on one or both sides with a fleece lamination is available as a roll.

Materials made of polyurethane, polyolefin, polyvinyl chloride, polyether or polyester with different densities can be used as foams. The laminating process for producing the molded part F has the following process steps:

- Back injection, back pressing or compression molding of a base layer 1 b consisting of foam or fleece-coated foam to form a shaped body 1.

- Applying an adhesive layer 2 to the free surface of the base layer 1 b and gluing with the decor 3, which is preferably made of leather.

The method can be used to produce a soft-touch effect on molded parts F with a decorative surface in a very simple manner.

Claims

PATENT CLAIMS 1. Laminating process for the production of molded parts with a decorative surface, in particular for vehicle interiors, by gluing a molded body (1) with a plastic base body (1a) to a Decor (3), the molded body (1) having a base layer (1b) with a free surface being produced in the lamination area by means of a direct method, for example by means of back-pressing, back-molding, press-molding or the like, an adhesive layer (2) on the free surface the base layer (1b) is applied and a decor (3) is pressed onto the surface of the base layer (1b), and preferably leather, suede or flat fabric is used as the material for the decor (3), characterized in that for the base layer (1 b) a foam is used. 2. Laminating process according to claim 1, characterized in that the Foam is provided at least on one side with a fleece lamination, to which the plastic forming the base body is applied in a direct process. 3. Laminating process according to claim 1 or 2, characterized in that polyurethane, polyolefin, polyvinyl chloride, polyether or polyester is used as the material for the foam. 4. molded part with a decorative surface, in particular for vehicle interiors, with a plastic base body produced by means of a direct process (1a) having molded bodies (1) with a support layer (1b) having a free surface, to which a decor (3) is glued, produced using the laminating process according to one of claims 1 to 3 2, characterized in that the base layer (1 b) is or has a foam layer. 5. Molding according to claim 4, characterized in that the foam is provided at least on its side connected to the plastic base body (1a) with a fleece lamination. 6. Molding according to claim 4 or 5, characterized in that the foam is also provided on its side connected to the decor (3) with a fleece lamination. 7. Molding according to one of claims 3 to 6, characterized in that the foam consists of polyurethane or polyolefin.