DE10119494A1 - Preparation of profiled leather object useful for automobile upholstery and instrument panels, having at least one leather layer and a protective layer made from a thermoplastic polymer bonded to the leather layer - Google Patents

Abstract

Preparation of profiled object having at least one leather layer and a protective layer made from a thermoplastic polymer bonded to the leather layer, the leather forming the leather layer is applied to a temperable profiling surface of a forming tool, some melt of the thermoplastic layer is applied to the leather at a first pressure, the forming tool is closed forming a negative mold, and the profiled part is finally formed at a higher pressure Preparation of profiled object having at least one leather layer and a protective layer made from a thermoplastic polymer bonded to the leather layer, the leather forming the leather layer is applied to a temperable profiling surface of a forming tool, part of a melt of the thermoplastic layer is applied to the leather at one pressure, the forming tool is closed forming a negative mold, and the profiled part is finally formed at a higher pressure, and the temperable profiled surface is tempered, at least during final forming, at a temperature low enough to ensure no damage to the leather layer. An Independent claim is included for a profiled body comprising a leather layer and a protective layer of thermoplastic polymer bonded to it, obtained as above.

Description

The invention relates to a method for producing a shaped body, which at least one leather layer and a support layer connected to the leather layer a thermoplastic polymer, and one according to this method manufactured molded body.

For vehicles in the higher price category, it is used to generate an exclusive It is common practice to line the interior of the vehicle with leather. To do this, the preformed molded parts such as door linings, dashboards, Center consoles, panels or handles with appropriately tailored and if necessary, preformed leather structures. Especially in the case of not The surface of the leather has to be flat in a separate work step sewn or pulled separately. Such a lamination of molded parts is only difficult to automate and very expensive due to the high proportion of manual work. The so far The usual cladding methods only lead to unsatisfactory results. So emissions of solvents and residual monomers from the adhesive systems in Purchase.

Especially in automobiles, the panels are very extreme temperature or Exposed to fluctuations in moisture, causing it to fade Warping of the leather lining can occur. Also suitable for that so far Usual cladding process only selected first quality grain leather.

Other areas in which a lamination of molded parts with leather is used arrived, for example, suitcases or furniture. For example, Hard-plastic backrests and seats of chairs covered with leather.  

Usually, in addition to the visual impression of the leather-clad molded parts, the impression is also important that arises when touching. The surface should feel pleasant, so have a "soft touch". So far, the leather has been used for this purpose in one separate work step first covered with a foam layer. The so obtained The bond was then made by gluing to the substrate, for example one Molded part made of hard plastic. In both operations, solvents are used based adhesive systems, dispersion adhesives or two-component reactive resin systems used so that inevitable emissions of solvents and residual monomers in Purchase must be made.

DE-OS 21 44 371 describes a method for embossing leather in an HF Field described. This is the permanent connection of a leather or backing layer with PVC or PUR layers using a heat-reactivatable, if necessary, blowing agent-containing adhesive in a high-frequency press simultaneous embossing created in the same operation.

DE 197 52 058 describes a method for back-foaming a lap seam having described leather fittings. Here, a leather molding with his Place the front on the mold half of a suitable tool and then in this on the back of the leather molding the plastic material under at least slight pressure development applied. According to the invention in the area of Cross seam between the upper leather piece and the lower leather piece encountered step-like height difference by a between the leather front and the tool mold half inserted transition piece compensated. About the Process conditions of the back injection of the leather with the plastic material no further details are given.

EP 0337183 B1 describes a method for shaping natural leather, in particular described by real leather cladding of molded parts. It is in the bottom of the Leather is pressed into a polyurethane barrier layer, which reactivates by heating becomes. Viscosity and quantity of those applied to the underside before the pressing process Polyurethane layer are coordinated so that the thickness of the barrier layer 35% to 65% of the thickness of the leather layer is. Following the barrier layer then foamed a molded part.  

DE 299 16 377 U1 describes a leather, in particular a grain leather, whose visible side has the scar structure, or one with a dressing forming the visible side provided split leather, the one on the opposite side of the visible side Back has a layer which is designed as a foam coating. The layer is achieved by applying a liquid plastic material and then solidifying it the same produced by fluid withdrawal. In this way, a leather with a "soft-touch" can be provided with a low basis weight.

DE 198 15 115 A1 describes a leather-clad interior part and a Process for gluing a real leather layer to a substrate is described. The leather-clad interior part for vehicles has a rigid shaped carrier part or a flexible spacer pad on which an adhesive bonding layer Real leather layer is arranged. The adhesive connection layer consists of a flat Carrier structure and a pre-dosed heat-reactive hot melt adhesive. to The individual layers are arranged on top of one another to produce the interior trim part and briefly heated to a temperature at which the Hot melt adhesive melts.

DE 198 18 034 describes a device for producing foam-backed materials Leather parts, in particular leather trim parts for the interior of Vehicles described. A leather part is made into an upper shape and a Tool with lower mold inserted, the tool closed and the Foam back side of the leather part according to the mold. There are several such tools installed on a rotary table system, each tool in the course the rotary movement of the rotary table, at least the following stations happened: one Insertion station, a masking station, a foam insertion station, a curing station and a removal station.

From the applicant is in the post-published patent application 199 51 776.2 Method for producing a three-dimensional molded part with a carrier from a thermoplastic polymers and a layer of leather arranged on the carrier have been proposed, the leather and the thermoplastic polymer with a Tool that has a shaped surface on which the leather comes into contact with one Pressure of at least 50 bar, preferably more than 100 bar, in particular more than 180 bar, and a temperature of more than 100 ° C, preferably 180 to 260 ° C, in particular  200 to 250 ° C, are connected, wherein the mold surface of the leather Tool is tempered.

Due to the temperature control of the mold surface, the back injection can be carried out with the thermoplastic polymers can be selected very high temperatures without the Structure of the leather is destroyed. This way, a very intimate connection can be made can be achieved between polymers and leather, so that the molded part has a very high Resistance to fluctuations in temperature and humidity is maintained without an adhesive layer between leather and thermoplastic polymers is required.

The leather trim of a vehicle is made in different sections different demands on the "soft touch" of the leather surface.

If the leather surface is only perceived, such as that Cladding in the footwell or the base of the seats will meet only minor requirements the "soft touch" because these areas are normally not used by a user be touched.

Other areas, such as the dashboard, handles, the steering wheel or Side panels of the doors, however, are in the grip area of the passengers, which is why higher demands are placed on the "soft touch" of the surface without For example, a particularly strong cushioning effect is required.

Finally, there are also areas in which an increased cushioning effect is required such as seats or armrests, which is why the surface of the Molded parts must be designed much more flexible than in those described above Areas.

The object of the invention is to provide a method for producing a shaped body To provide which has at least one leather layer and one with the leather layer bonded support layer made of a thermoplastic polymer, wherein Shaped bodies are obtained that are extremely robust against the action of Are heat or moisture and on the other hand a surface with a "soft touch" exhibit.  

The object is achieved with a method for producing a shaped body which comprises at least one leather layer and a support layer made of a thermoplastic polymer connected to the leather layer, wherein
a leather forming the leather layer is placed on a temperature-controllable molding surface of a molding tool,
a first amount of a melt of the thermoplastic elastomer is applied to the leather at a first pressure,
the mold is closed to form a negative mold,
and the molded part is finally shaped at a second pressure which is selected to be higher than the first pressure,
the temperature-controllable molding surface being tempered to a temperature at least during the final shaping that the leather layer is not damaged.

By the measure that first the melt of the elastomer at low pressure is positioned on the leather and after the tool is closed, the fitting is added a higher pressure is molded, the pressure with which the connection between polymers and leather, choose much lower than the direct injection. This allows the polymer to penetrate less deeply Leather can be realized, whereby during the connection of polymer and leather Leather layer is pressed less strongly. This leaves the structure of the Leather better preserved, so that when you touch the leather surface gives a feeling becomes, for example, like that of glued leather layers.

Sufficient heat dissipation is ensured by the tempered molding surface, so that the leather structure is not overcooked by the hot polymer melt, so it is destroyed. At the same time, the high temperature makes the elastomer melt sufficient low viscosity of the melt can be achieved, so that an intimate connection between Leather and polymer are created.

The task of applying the first amount of a melt of the thermoplastic polymer to the Leather is preferably made without pressure. First of all, there will be a sufficient amount Polymer melt applied to the leather, then the tool closed and then a sufficiently high pressure is applied to the connection between polymer and To produce leather.  

Leather and polymers are combined without the effect of an adhesive. It it is believed that the polymer due to the high pressure and temperature in the leather penetrates, creating an irreversible connection. There is no Work step in which the adhesive is applied to the leather or the polymer. Thus, emissions of solvents and residual monomers from an adhesive completely avoided. The leather and the polymer are all over Contact area connected to each other. The connection between leather and polymer is so intense that when trying to separate leather and polymer layer from each other, the structure of the leather or the polymer layer is destroyed. Even with intense ones Temperature loads, such as those in southern countries on the Dashboard behind the windshield, there will be no tension generated, which lead to destruction of the molded body. Rather, they are replaced by a Shrinkage of the leather created tension entirely from the backing collected. Permanent lamination is also possible with the method according to the invention difficult shaped pieces possible. For example, leather-clad Backrests of chairs are made, even with prolonged use on the concave side of the backrest no detachment of the leather layer from the support layer to be watched.

Another advantage is that the polymer shrinks slightly on cooling. The other layers of the molded body, in particular the leather layer, are therefore slightly compressed and are under a slight compressive stress. Will the If the leather layer is injured, for example, by incisions, the cut surfaces do not gap apart. The cut edges are caused by the compressive stress of the leather layer pressed together so that no deterioration in the visual appearance occurs. This is of great advantage, for example, with suitcases, as this also applies to show no excessive signs of wear for prolonged use.

When exposed to moisture, the process according to the invention also shows manufactured moldings no significant changes. This is an advantage at Convertibles, in which the leather lining is destroyed by unintentional Exposure to moisture, for example due to rain, largely or even completely can be avoided.

All common types of leather are per se for the process according to the invention usable. By tempering the mold surface of the tool  Overheating and destruction of the leather structure due to the comparatively high pressure Polymers pressed in at high temperature are effectively avoided. It can be both metal salt-tanned leather, e.g. B. chrome leather can be processed, which is a hydrothermal Have stability of approximately 100 ° C, as well as metal salt-free leather, which Have hydrothermal stability of around 70 ° C. Examples of such leather are Vegetable leather, chamois leather and FOC (free of chrome) leather. Are particularly suitable Leather with low heat shrinkage. Such leathers are mainly obtained from metal salt-free ones Tanning. The production of such leather is used for. B. in "Das Leder", 1992 (43), pages 283 ff described in detail. By cooling the mold surface of the tool low hydrothermal load on the leather.

For processing, it has proven to be beneficial if the leather is as dry as possible is. The leather preferably has a moisture content of less than 20% by weight.

The visible side of the leather that comes into contact with the molding surface of the molding tool can be pretreated, for example provided with a layer of paint.

The quality of the leather is much lower than that of the Procedures in which a connection is made by gluing without a loss in the optical appearance or the properties when touching must be accepted. The method according to the invention can therefore also be used, for example Motor vehicles of the lower price segment have a leather interior at affordable prices Prices are offered, while at the same time a higher quality impression of the Interior is achieved by covering with leather. Another advantage is that there is less leather waste, since areas of the leather with less Quality can be processed.

In leather production after the wet end as well as after the finish process process chemicals and dyes to choose, the pressure and the withstand the thermal conditions of the back injection process. Especially those in the wet End-process fatliquors must be good in the collagen network be fixed so that no fat migration to the surface or in the Plastic occurs, which leads to undesirable gloss spots or grease contamination on the Surface or to impair the adhesion between leather and plastic can lead.  

The tanning agents used in pre-tanning and post-tanning should be selected in this way be that there is good fiber separation and the leather is a good light, heat and Have heat resistance. This is especially with glutardialdehyde in combination with synthetic tanning agents based on dihydroxidiphenyl sulfone. Regardless of the tanning agent chosen, one should always follow the west-end process sufficiently high shrinking temperature of at least 70 ° C when wet can be achieved.

Products that meet the specific requirements should also be used in the finishing process Withstand loads in terms of temperature and pressure during back injection.

The thickness of the leather used depends on the shape and application of the Leather component and can vary between 0.8 to 3.0 mm, usually a thickness from 1.0 to 2.0 and in particular from 1.2 to 1.8 mm is preferred.

All known polymers are used as injection molding or injection molding plastics Carrier materials in question. Are suitable for. B. thermoplastic polymers such as Polyolefins, e.g. B. polypropylene or polyethylene, polyvinyl chloride, polysulfones, Polyether ketones, polyester, e.g. B. polybutylene terephthalate (PBT) and Polyethylene terephthalate (PET), polycycloolefins, polyacrylates and polymethacrylates, e.g. B. Polymethyl methacrylate, polyamides, polycarbonates, polyurethanes, polyacetals, such as Examples include polyoxymethylene (POM), polybutylene terephthalates and polystyrenes. Both homopolymers and copolymers of these thermoplastic are Polymers can be used. Acrylonitrile / butadiene / styrene (ABS) are particularly suitable - Polymers, also as mixtures of ABS polymers, acrylonitrile / styrene / acrylic ester (ASA) - Polymers, styrene / acrylonitrile copolymers, methyl methacrylate / acrylonitrile / butadiene / styrene Polymers and mixtures of different styrene / butadiene polymers, Styrene / butadiene block copolymers and vinyl chloride / acrylate graft copolymers.

ABS polymers are u. a. for impact-modified styrene / acrylonitrile Polymers in which graft copolymers of styrene and acrylonitrile Polybutadiene rubbers are present in a copolymer matrix made of styrene and acrylonitrile. ASA polymers are generally impact-modified Styrene / acrylonitrile polymers understood, in which graft copolymers of vinyl aromatic compounds, especially styrene and vinyl cyanides, in particular Acrylonitrile, on polyalkylacrylate rubbers in a copolymer matrix from in particular  Styrene and acrylonitrile are present. For example, the commercial product comes into question here Luran® S (BASF AG). Also suitable are styrene / acrylonitrile copolymers (SAN), Methyl methacrylate / acrylonitrile / butadiene / styrene polymers, e.g. B. Commercial product Terlux® (BASF AG) and mixtures of different styrene / butadiene polymers, Stryrene / butadiene block copolymers and vinyl chloride / acrylate graft copolymers. The back injection molding material or back molding material is preferably made of polypropylene, Polyamides, polybutylene terephthalate, thermoplastic polyurethanes, polyethylene, Polycarbonates or ABS polymers and their mixtures together.

The support layer preferably consists of polypropylene, polyamides, Polybutylene terephthalate, thermoplastic urethanes, polyethylene or from copolymers of styrene with minor proportions of one or more comonomers such as Example butadiene, α-methylstyrene, acrylonitrile, vinyl carbazole and esters of acrylic, Methacrylic or itaconic acid, especially acrylonitrile / butadiene / styrene polymers and their mixtures. The support layer used in the method according to the invention can also contain recyclates from these thermoplastic polymers.

The preferred polybutylene terephthalate is a higher molecular weight Esterification product of terephthalic acid with butylene glycol and a melt flow rate (MFR) according to ISO 1133, at 230 ° C and under a weight of 2.16 kg from 5 to 50 g / 10 Minutes, especially from 5 to 30 g / 10 minutes.

Copolymers of styrene include, in particular, copolymers with up to 45% by weight, preferably with up to 20% by weight of copolymerized acrylonitrile. Such copolymers of styrene and acrylonitrile (SAN) have a melt flow rate (MFR), according to ISO 1133, at 230 ° C and under a weight of 2.1 kg, from 1 to 25 g / 10 Minutes, especially from 4 to 20 g / 10 minutes.

Other copolymers of styrene which are also preferably used contain up to 35% by weight. %, in particular up to 20% by weight, copolymerized acrylonitrile, up to 35% by weight, in particular up to 30% by weight of copolymerized butadiene. The melt flow rate such copolymers of styrene, acrylonitrile and butadiene (ABS), according to ISO 1133, at 230 ° C and under a weight of 2.16 kg is in the range of 1 to 40 g / 10 minutes, especially in the range of 2 to 30 g / 10 minutes.  

Polyolefins such as polyethylene or polypropylene, in particular, are also used as materials for the carrier, the latter being preferably used. The term “polypropylene” is intended to mean both homopolymers and copolymers of propylene. Copolymers of propylene contain minor amounts of copolymerizable monomers with propylene, for example C ₂ -C ₈ -alk-1-enes such as ethylene, but-1-ene, pent-1-ene or hex-1-ene. Two or more different comonomers can also be used.

Particularly suitable carriers include homopolymers of propylene or Copolymers of propylene with up to 50% by weight of other alk-1-enes copolymerized up to 8 carbon atoms. The copolymers of propylene are statistical copolymers or block or impact copolymers. Provided the copolymers of propylene are statistical they generally contain up to 15% by weight, preferably up to 6% by weight %, other alk-1-enes with up to 8 carbon atoms, in particular ethylene, but-1-ene or a Mixture of ethylene and but-1-ene.

Block or impact copolymers of propylene are polymers in which, in the first stage, a propylene homopolymer or a random copolymer of propylene with up to 15% by weight, preferably up to 6% by weight, of other alk-1 -en produces with up to 8 carbon atoms and then in the second stage a propylene-ethylene copolymer with ethylene contents of 15 to 80% by weight, the propylene-ethylene copolymer additionally containing further C ₄ -C ₈ alk Can contain -1-ene, polymerized. As a rule, so much of the propylene-ethylene copolymer is polymerized in that the copolymer produced in the second stage has a proportion of 3 to 60% by weight in the end product.

The aforementioned polymer materials are generally known, for example from H. Domininghaus, The plastics and their properties, VDI-Verlag, Düsseldorf (1992).

The material of the support layer can be 1 to 60, preferably 5 to 50, particularly preferably 10 to 40 wt .-%, based on the total weight of the support layer, of reinforcing Fillers contain, such as barium sulfate, magnesium hydroxide, talc an average grain size in the range of 0.1 to 10 µm, measured according to DIN 66115, Wood, flax, chalk, glass fiber, coated glass fibers, long or short glass fibers, Glass balls or mixtures of these. You can also see the material of the carrier nor the usual additives such as light, UV and heat stabilizers, carbon blacks, lubricants or flame retardants and the like in the usual and required amounts Add.  

Leather as a natural material cannot be exposed to any high temperatures without that denaturation of the leather structure occurs. Common chrome leather show one hydrothermal stability of 100 ° C, while other leathers have hydrothermal stability of 70 ° C. It has now been found that a boiling of the leather and one Destruction of the leather structure when connecting the leather and the thermoplastic Polymers can be effectively avoided if the molding surface is close to the leather of the mold to a temperature of 10 to 80 ° C, preferably 20 to 60 ° C is cooled. The leather side of the finished molding shows in its optical Appearance no change due to the connection with the thermoplastic Polymers. The information conveyed when touching the finished molded part is also correct The feel of the leather surface matches the typical leather feel. Despite the application high temperatures and high pressure when joining leather layer and thermoplastic polymers shows the leather side of the finished molded part Resilience and softness, such as when gluing with leather a support layer is reached. The leather structure is the inventive Process not irreversibly compressed and thus hardened.

The pressure with which the connection between leather layer and thermoplastic The amount of polymers produced is in itself only due to the technical Limited conditions of the tool used. A permanent connection between leather and thermoplastic polymer is already from a pressure of 50 bar reached. Very good results are obtained at pressures above 100 bar, in particular achieved more than 180 bar. For very large workpieces, e.g. dashboards, is also worked with significantly higher pressures, for example 1000 bar. The Depth of penetration of the polymer into the leather and thus the "soft touch" of the leather surface the fitting can be in the inventive method by the choice of Influence pressure very precisely. In the first step, in which the melt of the Thermoplastic polymer is given to the leather with a low Pressure worked. It is not yet necessary here for a connection between Polymer and leather are made. The first pressure is therefore preferably in the range of Ambient pressure and 120 bar, preferably between ambient pressure and 100 bar selected. The first pressure between ambient pressure and 50 bar is particularly preferred and particularly preferably selected between ambient pressure and 20 bar. Under Ambient pressure is understood to mean that the polymer melt has no pressure on the leather is abandoned. Leather and polymers are combined in another  Process step, in which process step the pressure ranges specified above are preferred.

The processing temperature of the plastic is dependent on the one used Plastic chosen. Advantageous for a good connection between leather and Thermoplastic is a high fluidity of the thermoplastic. Cheap the melt flow rate (MFR) is 230 / 2.16 <g / 10 minutes, preferably between 10 to 50 g / 10 minutes. The melt flow rate (MFR) is according to ISO 1133 at 230 ° C and determined under a weight of 2.16 kg. There is also a low content of the polymer on wetting agents such as glycerol monostearate advantageous for good adhesion. As cheap contents of less than 5000 ppm of wetting agent have been found.

The leather can be pressed into the mold by the inflowing polymer melt. However, it is preferred that the leather before giving in the first amount of the melt thermoplastic polymer is deep drawn. This way is an exact Positioning of the leather is possible, which results in a more precise shape. This is particularly advantageous in the production of large components, such as dashboards, or for components with a complex structure.

In the process according to the invention, tools in plastics technology can be used as tools usual equipment is used and it is essential that each on the leather side of the molded part can be provided for sufficient heat dissipation.

The use of low pressures and temperatures enables a gentler one Injection molding or embossing of decorative materials. There are different ones Process has been developed. An overview of such procedures is given for example given in "Cost reduction through innovative injection molding", VDI- Gesellschaft Kunststofftechnik - Düsseldorf, VDI-Verlag 1997, pp. 114 to 121; "Plastics in automotive engineering: raw materials, components, systems", VDI society Kunststofftechnik - Düsseldorf, VDI-Verlag 1994, pp. 280 to 313.

According to a preferred embodiment, the molded body is produced after the injection molding process. Injection stamping is a process of injection molding technology Here, the injection mold still has a small one in the injection phase Opening up. This is due to the resulting greater wall thickness lower melt pressures achieved in the tool, which leads to an improved "soft touch" of the  Leather surfaces leads. After injecting an appropriate amount Polymer melt, the injection mold is closed and the polymer melt at high pressure pressed with the leather.

If there is still polymer melt to completely fill the injection mold during the Closing process is needed, a second amount of the finished molding Melt the thermoplastic polymer in the negative mold. Under Negative form is understood to mean the hollow form in the tool, which is the one obtained later Molded body corresponds.

According to a further advantageous embodiment, the Shaped body according to the strand laying process. The strand laying process also poses is a process of injection molding technology. In this process, the Polymer melt by a plasticizing unit, in which the polymer melt is produced, into the opened tool. The first print therefore corresponds to that in the sense of the invention Ambient pressure. After applying the appropriate amount of polymer melt to the In leather, this polymer melt is pressed by closing the two Mold halves. As a result, the pressure in the tool rises sharply. This higher pressure, in which the molded part is finished molded corresponds to the second in the sense of the invention Print. This process can also lower melt pressures in the mold be realized, which has a positive effect on the "soft touch" of the leather surface.

The surface of the leather side of the molded body can be when the molded body is molded their design can be modified in the same step by using the leather adjacent mold surface of the mold has an embossed structure. The through the The molded surface of the tool embossed or grained is irreversible. It is therefore, for example, the emblem of a very easily possible in the molded body Manufacturer. When processing inferior leather, leather defects can occur be perforated. When connecting leather layer and thermoplastic polymer holes in the leather are filled and evened out by the polymer melt. The Thermoplastic polymers take on the shape of the molding surface The exact same surface structure as the surrounding one Leather surface. Color matching can be done, for example, by a subsequent one Pigment painting can be created.  

The properties of the molded part can be further modified by the thermoplastic polymers is foamed. This way Realize weight savings without losing the stability of the molded part have to be accepted. For practical use, for example for Door panels in automobiles, backrests and seats of chairs as well Hard cases have proven gas contents, which lead to a reduction of the specific weight, based on the unfoamed thermoplastic polymer, of 5 lead to 40%. The pore size and the pore size distribution per se can be arbitrary to get voted. Different pore structures can also be used. It Both open and closed-cell foams can be used. That for Foaming agents used are not particularly limited per se subjected. Endothermic blowing agents such as citric acid, carbonates, Dicarbonates or mixtures thereof can be used under the influence of heat Release gas when injecting. Other suitable blowing agents are azodicarbonamide, Sulfohydrazides and semicarbazides.

Commercially available blowing agents are, for example, Hydrocerol® HK, Hydrocerol® CF 40S and Exocerol® OM 70A, which are sold by Boehringer Ingelheim, or also Luvopor® ABF / 20 G-UT, Luvopor® HT powder and Luvopor® VP 9060, made by Lehmann and Voss are distributed. Physical blowing agents such as nitrogen can also be used or carbon dioxide can be used, for example in the supercritical state be used. A particularly fine-pored foam with a narrow pore distribution can be obtained using the MuCell process (Microcellular Foam). This Foaming process is described for example in WO 99/63019. By the Foaming of the polymer can, for example, the bending stiffness of the molded part be modified. When correcting leather defects by filling in with the thermoplastic polymers are compensated for by foaming the polymer the elasticity created between the leather layer and the polymer. The in this case, the repaired area is practically no longer palpable. It will too supported by the shrinkage of the thermoplastic polymers on cooling. In the repaired areas arise no recesses. After an appropriate pigmentation is therefore also at oblique Incident light does not affect the repaired area compared to the surrounding leather surface to recognize more.  

Further modifications of the method according to the invention are also possible. So can the visual impression of a repaired defect in the leather surface be improved if the thermoplastic polymer is colored, preferably in its coloring is matched to the color of the leather. In combination with a light The repaired leather flaw is no longer recognizable in pigment coating. The one with the Molded articles which can be produced by the process according to the invention are extremely inexpensive Properties such as high robustness against the effects of temperature or Moisture, while at the same time a "soft touch" of the surface is guaranteed. The invention therefore also relates to a shaped body comprising at least one Leather layer and a support layer connected to the leather layer from one thermoplastic polymer, which by a method according to any one of claims 1 to 9 is obtained.

Due to the penetration of the thermoplastic polymer into the leather layer Leather layer and carrier irreversibly connected. A detachment of the Leather layer from the carrier is only under for most common plastics Destruction of the leather structure possible. In the molded part according to the invention Connection of leather layer and carrier no additional material required as an adhesive. A characteristic of the three-dimensional molded part according to the invention is, in addition to that pronounced "soft touch" the absence of an adhesive layer between leather and Carrier.

The depth of penetration of the thermoplastic polymer into the leather is normally 5 up to 40%, preferably 10 to 30%, of the thickness of the leather layer. The required Depth of penetration depends on the leather thickness, the demands on the mechanical Resilience and the desired "soft touch". Common leather thicknesses are in the range of 1 to 2.0 mm.

The moldings according to the invention can be used in a large number of applications be used. In addition to the use already mentioned in the automotive industry for the Paneling of dashboards, for interior panels, center consoles and the like. s. w. is for example, a design as a protective cover for mobile phones, equipment from Shell cases with leather surfaces or an insert in the shoe or Apparel industry for direct molded caps, shoulder boards and Protective clothing items conceivable. Another area of application is, for example Furniture industry. Here is an embodiment of the molded body as a backrest, seat  or armrest on seating furniture. The invention is far beyond those mentioned Application examples can also be used.

The invention is explained in more detail below with the aid of examples.

example 1 Production of molded articles reinforced with polypropylene according to the Injection-compression molding

A rectangular piece of leather [(FOC leather, wet-white) from BASF AG Ludwigshafen, DE] with an edge length of 50 × 130 cm and a thickness of 1.6 mm was made into a Injection mold inserted. The mold surface was heated to a temperature of 40 ° C. The injection mold was closed so far that an opening gap of 5 to 10 mm remained. Then a propylene homopolymer reinforced with 40% by weight talc was added a melt flow rate (MFR) according to ISO 1133 of 15 g / 10 minutes at 230 ° C and 2.16 kg, which was heated to a temperature of 250 ° C under a spray pressure of 80 bar injected. Then the injection mold was completely closed and more Polymer injected under an injection pressure of 300 bar. The tool was depressurized cooled to a temperature of 30 ° C within a period of 1 minute. Then the injection mold was opened and the resulting three-dimensional shaped body taken.

An optical inspection of the molded body showed that the leather surface of the Shaped body has no discoloration or other irregularities. At the Touching the leather surface gives a typical feeling of leather.

Example 2 Production of molded articles reinforced with polypropylene according to the The melt application method

A rectangular piece of leather [(FOC leather, wet-white) from BASF AG Ludwigshafen, DE] with an edge length of 50 × 130 cm and a thickness of 1.6 mm was made into a Injection mold inserted. The mold surface was heated to a temperature of 40 ° C. Then, with the injection mold open, one by one  Plasticizing unit heated to 250 ° C polymer melt (propylene homopolymer) on which Meat side of the leather piece filed. Then the mold halves of the Injection mold closed and the polymer melt at a pressure of 300 bar pressed into the leather. The tool was depressurized within a period of 1 Minute cooled to a temperature of 30 ° C. Then the injection mold opened and the resulting three-dimensional shaped body removed.

An optical inspection of the molded body showed that the leather surface was none Discoloration or other irregularities. When touching the Shaped body subjectively creates the typical leather feel.

Example 3 Production of a molded body reinforced with ABS polymer

Analogous to Example 1, a rectangular piece of leather [(FOC leather, wet white) from the company BASF AG Ludwigshafen, DE] with an edge length of 50 × 130 cm and a thickness of 1.6 mm placed in an injection mold. The mold surface was at a temperature tempered from 60 ° C. The injection mold was closed so far that a Opening gap of 5 to 10 mm remained. Then an ABS polymer (Terluran® GP22), which was heated to a temperature of 250 ° C, under a spray pressure of 80 bar injected. Then the injection mold was completely closed and more Polymer injected under an injection pressure of 300 bar. The tool was depressurized cooled to a temperature of 30 ° C within a period of 1 minute. Then the injection mold was opened and the resulting three-dimensional shaped body taken. An optical inspection of the molded body showed that the leather surface there was no discoloration or other irregularities in the molded body. At the Touching the molded body subjectively set the typical leather feeling.

Example 4 Production of a molded part reinforced with glass fiber reinforced PBT / ASA

As described in Example 3, a rectangular piece of leather was injection molded reinforced with plastic. Instead of Terulan® GP22, however, glass fiber reinforced PBT / ASA (13% by weight glass fiber content; Ultradur® S; BASF AG  Ludwigshafen, DE) used. The polymer melt was applied in a plasticizing unit Heated to 270 ° C and placed on the meat side of the leather. The mold surface of the tool was tempered to a temperature of 80 ° C in this case. The back injection pressures used correspond to the conditions described in Example 3.

In this example, too, an optical inspection of the shaped body showed that the Leather surface of the molded body no discoloration or other irregularities having. When touching the leather surface, a typical leather feeling is also felt here taught.

Claims (10)

1. A process for producing a molded body which comprises at least one leather layer and a support layer made of a thermoplastic polymer connected to the leather layer, wherein
a leather forming the leather layer is placed on a temperature-controllable molding surface of a molding tool,
a first amount of a melt of the thermoplastic polymer is applied to the leather at a first pressure,
the molding tool is closed to form a negative mold and the molding is finished molded at a second pressure which is higher than the first pressure,
the temperature-controllable molding surface being tempered to a temperature at least during the final shaping that the leather layer is not damaged. 2. The method according to claim 1, wherein the heatable mold surface to a temperature from 10 to 80 ° C., preferably 20 to 60 ° C. 3. The method of claim 1, wherein the first pressure between ambient pressure and 120 bar, preferably ambient pressure and 100 bar, is selected and the second Pressure at least 50 bar, preferably more than 100 bar, in particular more than 180 bar is. 4. The method according to any one of claims 1 to 3, wherein the leather before the task of first amount of the melt of the thermoplastic polymer is deep-drawn. 5. The method according to any one of claims 1 to 4, wherein the production of the shaped body after the injection molding process.   6. The method according to any one of claims 1 to 5, wherein a during the final molding second amount of melt of the thermoplastic polymer in the negative form is given. 7. The method according to any one of claims 1 to 4, wherein the production of the shaped body after the strand laying process. 8. The method according to any one of claims 1 to 7, wherein the molding surface is an embossed structure having. 9. The method according to any one of claims 1 to 8, wherein the thermoplastic polymer is foamed, especially up to a reduction in specific density, based on the unfoamed thermoplastic polymer, from 5 to 40%. 10. Shaped body, comprising at least one leather layer and one with the leather layer bonded support layer made of a thermoplastic polymer, available with a Method according to one of claims 1 to 9.