DE102011119567A1 - Molded part useful for interiors of vehicles, comprises carrier with wood fiber molding material made of hot pressed, cross-linked binder and attachment part, which is connected positively with carrier by thermal welding layer - Google Patents

Abstract

Molded part comprises a carrier (3) containing wood fiber molding material made of hot pressed, a cross-linked binder and at least one attachment part (10), which is at least partially coated with a hot melt adhesive and/or consists of a thermoplastic material, where at least one attachment part is connected positively with the carrier by a thermal welding layer, and the thermal welding layer comprises cross-linked binder and hot melt adhesive and/or crosslinked binder and thermoplastic material. Independent claims are also included for: (1) producing the molded part, comprising (i) providing the wood-fiber mat-shaped molding material containing the thermosetting binder, (ii) providing at least one attachment part, which is at least coated in sections with the hot melt adhesive and/or consists of the thermoplastic material to form the welding layer containing cross-linked binder and hot melt adhesive and/or crosslinked binder and thermoplastic material, (iii) providing a temperature controlled, two- or multipart pressing tool comprising first and second half-mold, (iv) arranging the mounting parts are in the first half-mold, (v) inserting the wood fiber molding material in the first half-mold with the disposed attachment parts, (vi) closing the mold by pressing together the two mold halves, and (vii) pressing the wood-fiber molded material at temperatures of 140-230[deg] C to the carrier, where the attachment parts are positively connected with the carrier; and (2) two- or multi-part pressing tool comprising first and second half-mold and heaters for heating the first and second tool half, where the pressing tool comprises at least one cooling device for partially cooling the first half-mold.

Description

The present invention relates to a molded article comprising a carrier of hot-pressed, a crosslinked binder containing wood fiber molding material and one or more attachments, which are coated with a first hot melt adhesive and / or consist of a thermoplastic material.

The molded part according to the invention is in particular a lining for the interior of vehicles. Moldings or interior trim parts for vehicles with a carrier and attachments, such as holders for handles, trays and controls are known from the prior art.

In the interior of vehicles a variety of moldings is used, such as door side panels, headliners, instrument panels or instrument panels. The support of the molded part is made of plastic or preferably made of wood fiber molding material, planar and has a substantially planar or predetermined by the respective design three-dimensional contour with convex and concave areas and optionally one or more openings and recesses for moldings and controls such as buttons, Switches and knobs for windows and mirrors.

Usually, the carrier is coated with a decorative part. The carrier is usually made of plastics or plastic-containing composite materials, such as acrylonitrile-butadiene-styrene (ABS) or polypropylene (PP). Also used as the material for the carrier wood fiber molding materials based on textile fabrics of hemp, sisal, flax, kenaf and / or wood components, such as wood fibers, wood flour, wood chips or paper, bound with thermosetting binders. As a further material for the carrier come foamed materials of polyurethane or epoxy resins, which are optionally reinforced with natural fibers or glass fibers into consideration.

The vehicle interior facing side of the molding or the carrier is usually referred to as the visible side. In order to give the visible side an attractive appearance, the carrier is equipped with a decorative part of a textile material or a plastic film. The plastic films used for this purpose are mostly colored and have a relief-like embossed surface. Optionally, the decorative parts comprise a padding layer of a foamed plastic, which faces the wearer and gives the molding a pleasing feel. The decorative part is usually laminated to the carrier or glued in the production of the carrier by means of thermoplastic injection molding with this. The decorative part provided for thermoplastic injection molding has a coated rear side; Preferably, the back is coated with a fleece that protects the decorative part from overheating.

The carrier is expediently provided on the edge side and / or on a mounting side opposite the visible side with projections, depressions and bores. The projections, recesses and holes are used for non-positive connection of the molded part with parts of the bodywork, such as a car door or the roof of a passenger compartment by means of holding elements, such as brackets, pins and screws.

The attachments or brackets are referred to in professional circles as Retainer. Retainers are made of plastic or a metallic material, such as sheet steel and mechanically connected to the carrier by means of holding elements, such as pins, screws, staples or by entanglement, clawing or clamping. Retainers as an integral part expediently comprise claws and / or straps. The claws and tabs are intended to engage in the mounting of the retainer in recesses of the carrier or to be bent around the edge of the carrier and fixed by clamping.

For the production of moldings for the interior of vehicles, various methods are known, which usually comprise two or more than two production steps.

According to a known method, a carrier is first produced by hot pressing of a wood fiber molding material. Subsequently, on the mounting side of the carrier Retainer z. B. attached by friction welding or gluing. In a third step, one or more decorative parts are laminated to the visible side of the carrier. In a simplified, two-stage variant of the method retainers made of a metallic material with integrated holding elements, in particular with claws are pressed together with the wood fiber molding material, wherein the holding elements penetrate into the wood fiber molding material and anchoring the retainers frictionally to the support after its curing.

According to another known method, a carrier is produced by means of injection molding, in particular by means of rear injection molding of a thermoplastic material. One or more decorative parts are preferably arranged in a rear injection mold and back-injected with the thermally plasticized plastic. After cooling and solidification of the plastic melt, the decorative parts are non-positively bonded to the carrier. In a further step, attachments or retainers are mounted on the mounting side of the carrier.

Beams of wood fiber molding material are used to an ever-increasing extent for the interior of vehicles. Compared to plastics, wood fiber molding materials have some advantages. Thus, wood fiber molding materials are produced to a considerable extent from renewable resources, such as coniferous trees, hemp or kenaf. Technical and economic considerations are also reinforcing the trend towards wood fiber molded materials. Wood fiber moldings are lighter in weight with the same specific stiffness as glass fiber-polypropylene composites or talc-polypropylene composites. Carriers made of wood fiber molding material are characterized by their favorable crash and splinter behavior, good energy and sound absorption (even in the cold) and their comparatively low thermal expansion coefficient. The industry has many years of experience in the processing of wood fiber molding material, whereby the associated processes and hot press molding are robust or cost-effective compared to injection molding tools. Wood fiber molding materials allow the production of beams with pronounced undercuts and deflections at an angle of up to 180 degrees. Finally, wood and natural fibers are available in large quantities, with their price being less dependent on crude oil prices than petroleum-based plastics.

However, the production of moldings with a carrier made of wood fiber molding material is subject to some limitations in terms of manufacturing efficiency and the choice of attachments or retainers. By reducing the number of manufacturing steps, the production of the moldings can be simplified and accelerated. As described above, it is known. Attachment parts of a metallic material, in particular made of steel sheet together with the wood fiber molding material to be pressed, so that the complex, partially manual assembly of the attachments to finished, d. H. hot pressed and hardened carriers deleted. However, this method requires that the attachments are equipped with mechanical holding elements such as claws or staples and consist of a material that does not soften in the usual hot pressing of wood fiber molding material temperatures in the range of 190 to 230 ° C or a glass transition temperature above this Temperature range has. Accordingly, only attachments made of metallic materials come into consideration for the above manufacturing method. Attachments made of metallic materials have a high specific weight. Due to the metallic material and the holding elements required for the mechanical connection with the carrier, the shape of the attachments is severely limited. If practicable, the production of attachments with complex three-dimensional geometry made of metallic materials is so complex that their use is not eligible for cost reasons alone. In contrast, three-dimensional complex designed and lightweight attachments can be manufactured inexpensively from plastic by injection molding in large quantities.

The invention has the object to provide a molded part with attachments for the interior of vehicles, which is simple and inexpensive to produce, the attachments can be freely designed within wide limits and optimized in terms of economic and technical requirements and design specifications, an economical process to provide for the production of moldings of the type described above as well as to provide a device which makes it possible to compress carrier for moldings of the type described above together with attachments hot and in this case to temper the attachments separately.

This object is achieved with the features of the independent claims. Other embodiments of the invention are set forth in the claims appended hereto.

This object is achieved by a molded part, comprising a support of hot-pressed, a crosslinked binder containing wood fiber molding material and at least one attachment, which is at least partially coated with a hot melt adhesive and / or consists of a thermoplastic material, wherein the at least one attachment by a welding layer is connected to the carrier and the weld layer contains crosslinked binder and first hot melt adhesive or crosslinked binder and thermoplastic material. In this case, the at least one attachment can be connected by a welding layer to the carrier in particular non-positively.

• • das Formteil einen mit dem Träger verbundenes Dekorteil mit einer Sichtlage aus einem textilen Material oder einer Kunststofffolie umfasst;
• • das Bindemittel eine Aushärttemperatur von 140 bis 200°C aufweist;
• • der thermoplastische Werkstoff eine Erweichungstemperatur von 140 bis 180 Grad Celsius aufweist;
• • der Schmelzklebstoff eine Erweichungstemperatur 80 bis 160°C aufweist; und/oder
• • das Dekorteil mittels eines weiteren, zweiten Schmelzklebstoffs mit einer Erweichungstemperatur von 80 bis 180 Grad Celsius mit dem Träger verbunden ist.

Advantageous developments of the molding according to the invention are characterized in that:

• • The molded part comprises a decorative part connected to the carrier with a visible layer of a textile material or a plastic film;
• • the binder has a curing temperature of 140 to 200 ° C;
• • The thermoplastic material has a softening temperature of 140 to 180 degrees Celsius;
• • the hotmelt adhesive has a softening temperature of 80 to 160 ° C; and or
• • The decorative part is connected by means of another, second hotmelt adhesive having a softening temperature of 80 to 180 degrees Celsius with the carrier.

In the context of the invention, the term wood fiber molding material refers to a textile fabric, d. H. in particular a woven, knitted or non-woven fabric comprising fibers, chips, shavings or mixtures thereof. An example of a wood fiber molding material is wet laid or carded webs. The nonwovens may contain natural or synthetic fibers or mixtures of natural and synthetic fibers as well as chips or wood chips. As natural fibers or natural fibers are, for example, fruit fibers, seed fibers and stem fibers such as sisal, jute, hemp, kenaf, flax, cellulose and cotton and banana fibers and wool into consideration. Furthermore, synthetic fibers of polyester, polyacrylonitrile, polyamide, carbon, polyvinyl chloride, polyolefins such as polyethylene and polypropylene and inorganic materials such as aramid and glass are provided.

In particular, the wood fiber molding material comprises 60 to 80 weight percent wood fibers, 15 to 30 weight percent polyester fibers and 5 to 15 weight percent thermosetting binder based on phenolic resins or acrylates, with thermosetting acrylic-based binders being preferred.

For example, the wood fiber molding material includes polyester fibers having a length of about 50 to 80 mm and wood fibers having a length of about 2 mm. For the production of the wood fiber molding material wood chips from pine or spruce wood are cooked under a pressure of 5 to 10 bar and shredded with a disc refiner. The resulting wood fibers are glued with acrylate resin and dried by means of a fiber dryer to a residual moisture of 5 to 20 weight percent, based on the weight of the glued wood fibers.

On a thin underlay or transport fleece first the polyester fibers and subsequently the glued with acrylate resin wood fibers are placed and partially oriented. The resulting two-ply fiber web is compacted by means of rollers and a needle device to a needle felt and assembled by means of a cutting device into mats.

In another advantageous embodiment of the invention, the fiber molding material, based in each case on its total weight, comprises 30 to 70% by weight of natural fibers and 70 to 30% by weight of fibers of one or more thermoplastic polymers, in particular fibers of polypropylene and / or propylene copolymers, and optionally additives, such as binders, fillers and / or dyes, wherein the proportion of optional additives 0.5 to 15 wt .-%, based on the total weight of the fiber molding material. In this embodiment, the fibers are made of one or more thermoplastic polymers as a binder, which is plasticized in hot pressing of the fiber molding material and solidifies on cooling and the natural fibers bonded together or forms a solid matrix in which the natural fibers are embedded. Preferably, the fiber molding material comprises, based on its total weight 40 to 60 wt .-% of natural fibers and 60 to 40 wt .-% fibers of one or more thermoplastic polymers. The fiber-forming material is prepared in a similar manner as described above, wherein the natural fibers and the fibers of one or more thermoplastic polymers are first mixed together and optionally placed on a thin underlay or transport fleece. The mixing of the fibers preferably takes place in a turbulent air flow or in a swirling device. Following this, the amount of fiber is mechanically compressed into a web, optionally oriented and assembled by means of a cutting device. In an advantageous development of the above embodiment of the invention, the fiber molding material contains natural fibers and fibers of one or more thermoplastic polymers other synthetic fibers, especially carbon fibers, fibers of polyester, acrylic, aramid, Twaron, Kevlar, Technora, Vinalon, Zylon.

In the context of the present invention, the term "polymers" encompasses both homopolymers and copolymers of the polymer types mentioned.

The mat-like wood fiber molding materials have a thickness of 5 to 30 mm, preferably 10 to 20 mm and a basis weight of 80 to 4000 g / m ² , preferably from 500 to 2500 g / m ² , and in particular from 1200 to 2200 g / m ² .

Binders for the consolidation of fiber webs or wood fiber molded materials, in particular phenolic resins and resins based on acrylates are known.

For example, phenolic resins begin to crosslink at temperatures above 100 degrees Celsius while z. For example, aqueous dispersions based on polymers of styrene and at least one acrylate, which are modified with a polycarboxylic acid and a polyhydric alcohol as crosslinking component, crosslink at a temperature of 130 degrees Celsius. Other polymer dispersions used as binders have higher crosslinking temperatures in the range of 150 to 220 degrees Celsius.

According to the invention as a binder z. B. thermosetting resins based on phenol and formaldehyde, melamine-formaldehyde resins, urea-formaldehyde resins, one and two-component systems based on epoxy resins or polyurethanes, polyacrylates, polymethacrylates, polyvinyl acetates, styrene-acrylate copolymer dispersions, styrene Methacrylate copolymer dispersions, styrene-butadiene (meth) acrylic acid copolymer dispersions and mixtures of the dispersions mentioned with a mixture of a polycarboxylic acid and a polyhydric alcohol used as a crosslinking component.

• (a) einem Polymerisat, das durch radikalische Polymerisation erhältlich ist und das zu 5 bis 100 Gewichtsprozent eines ethylenisch ungesättigten Carbonsäureanhydrids oder einer ethylenisch ungesättigten Dicarbonsäure, deren Carbonsäuregruppen eine Anhydridgruppe bilden können, einpolymerisiert enthält und
• (b) mindestens einem Alkanolamin, das mindestens zwei Hydroxylgruppen im Molekül enthält.

Examples of preferred thermally curable binders are mixtures of:

• (A) a polymer which is obtainable by free-radical polymerization and which contains from 5 to 100 weight percent of an ethylenically unsaturated carboxylic acid anhydride or an ethylenically unsaturated dicarboxylic acid whose carboxylic acid groups can form an anhydride group in copolymerized form, and
• (B) at least one alkanolamine containing at least two hydroxyl groups in the molecule.

Specific examples of such mixtures are about 40 to 60 percent by weight (solids) aqueous solutions of a copolymer of 80 weight percent acrylic acid and 20 weight percent maleic acid having a molecular weight Mw of 15,000 to 900,000 in combination with triethanolamine or aqueous solutions of a copolymer 55% by weight of acrylic acid and 45% by weight of maleic acid in combination with triethanolamine. These binders may optionally comprise an esterification catalyst and / or a bound phosphorus-containing compound such as hypophosphorous acid as a reaction accelerator.

The copolymer (a) described above may for example also be composed of 50 to 99.5 weight percent of at least one ethylenically unsaturated mono- or dicarboxylic acid, 0.5 to 50 weight percent of at least one ethylenically unsaturated compound selected from the group of ethylenically unsaturated monocarboxylic acids and esters Monoesters and the diesters of ethylenically unsaturated dicarboxylic acids having at least one hydroxyl group-containing amine and up to 20 weight percent of another monomer.

Thermally curable, aqueous compositions containing at least one copolymer and at least one alkanolamine or higher functional beta-hydroxyalkylamine may optionally additionally contain at least one surfactant.

Further thermally curable binders are based on aqueous mixtures of polycarboxylic acids such as polyacrylic acid, polymethacrylic acid, copolymers of acrylic acid and maleic acid, copolyamines of methacrylic acid and maleic acid, copolymers of ethylene and maleic acid, styrene and maleic acid, or copolymers of acrylic acid or methacrylic acid and esters of acrylic or methacrylic acid preferably monohydric monohydric alcohols containing 1 to 24 carbon atoms, the polycarboxylic acids having a K value of 50 to 100 (measured in non-neutralized form of H. Fikentscher's polycarboxylic acids in dimethylformamide at 25 degrees Celsius and a polymer concentration of 0.1 percent by weight, polyhydric alcohols such as trimethylolpropane, glycerol, 2-hydroxymethylbutanediol-1,4 or polyvinyl alcohol and / or polyhydric amines and / or alkanolamines.

Polycarboxylic acids, polyhydric alcohols, alkanolamines and polyhydric amines are preferably used in amounts such that the number of acid function is equivalent to the total of alcoholic hydroxyl and amine functions. Also suitable are binders consisting of an aqueous solution of a polycarboxylic acid (homopolymer or copolymer) preferably having a molecular weight Mw of 10,000 or lower and a polyol such as triethanolamine, and in which the ratio of equivalents of hydroxyl groups to equivalents of carboxyl groups is in the range of 0 , 4: 1.0 to 1.0: 1.0.

Appropriately, binders of the type Acrodur ^® BASF AG can be used. An example of this is an aqueous styrene-acrylate polymer dispersion modified with a polycarboxylic acid and a polyhydric alcohol crosslinking component. Such a polymer dispersion begins to crosslink at a temperature of 130 degrees Ceslius. However, in order to achieve high production speeds, crosslinking is carried out at temperatures of 180 to 220 degrees Celsius. Another formaldehyde-free binder for wood and natural fibers, which is also suitable for the consolidation of glass and mineral fibers, is commercially available as a colorless to slightly yellowish, clear, aqueous solution of a modified polycarboxylic acid with a polyhydric alcohol as a crosslinking component. It crosslinks at drying temperatures of about 160 to 180 degrees Ceslius. In order to achieve a high degree of crosslinking, the production rate must be matched to the crosslinking time and crosslinking temperature.

The binders used are preferably low-formaldehyde or formaldehyde-free thermally curable products. Under low formaldehyde is to be understood in the present context that the binder does not contain significant amounts of free formaldehyde and that even when drying or curing of the materials treated with the binders no significant amounts of formaldehyde are released. In general, such binders contain less than 0.01% by weight of formaldehyde.

Particularly preferred are formaldehyde-free binders containing at least one polycarboxylic acid and at least one polyhydric alcohol and / or alkanolamine or polyhydric amine. Compositions containing these binders may optionally contain further formaldehyde-free binders, e.g. As polyacrylates, which are offered under the trademark Acronal ^® by BASF AG.

Any of the curable binders known for bonding nonwoven fabrics described above may be used in the invention for the wood fiber molding material. For example, a binder of the type Acrodur ^® of BASF AG come on the basis of at least one polycarboxylic acid and at least one polyhydric alcohol into consideration. In addition, mixtures of at least one curable binder and at least one other binder may also be used.

The attachments or retainer are made of a metallic or polymeric material and preferably made of a thermoplastic material having a softening temperature of 140 to 180 degrees Celsius. The attachments can therefore consist completely or only partially made of thermoplastic material. These sections are located at points or surface areas of the attachment, which touch the support of the molding during hot pressing. Specifically, for the attachments, materials such as steel sheet, polypropylene (hereinafter referred to as PP), acrylonitrile-butadiene-styrene (hereinafter referred to as ABS), and blends of acrylonitrile-butadiene-styrene and polycarbonate (hereinafter referred to as PC) are provided. Optionally, the attachments are made of a metallic material which is coated with colored lacquer.

In an advantageous embodiment of the invention, the attachments are coated with a first hot melt adhesive having a softening temperature of 80 to 160 ° C. The first hotmelt adhesive is preferably applied to sites or to surface regions of the attachment which touch the carrier of the molding during hot pressing. The hot melt adhesive is softened during hot pressing and forms in the subsequent cooling process an adhesive bond between the attachment and the carrier.

The present invention is based on the formation of one or more thermal adhesive bonds or welding layers between the carrier and the respective attachment. The thermal Klebevebindungen or welding layers cause anchoring of the attachments to the carrier. The anchoring can be formed purely cohesive. In order to improve the connection, a casting of undercut sections can additionally take place, so that the cohesive connection is supplemented by a form-fitting component.

In embodiments according to the invention in which the attachments are made of a thermoplastic material with a softening temperature of 140 to 180 ° C and the temperature during hot pressing of the carrier exceeds the softening temperature of the thermoplastic, the use of the first hot melt adhesive is not required. In this case, the thermoplastic part of the attachment is partially plasticized at the joining surfaces between the carrier or the heated wood fiber molding material and the attachment. The thermal welding layer is then formed from the plasticized plastic of the attachment and from the cured or crosslinked binder of the wood fiber molding material.

In alternative embodiments of the invention, in which the attachments are coated with a first hot melt adhesive having a softening temperature of 80 to 160 ° C and the temperature during hot pressing of the carrier exceeds the softening temperature of the first hot melt adhesive, the thermal welding layer of the first hot melt adhesive and from hardened or crosslinked binder of the wood fiber molding material formed.

To connect the carrier to the attachments, the regions or joining surfaces of two workpieces made of the same or different thermoplastic polymers A and B are heated to a temperature in the range of about 50 ° C. above their glass transition or softening temperatures (TG). During heating or immediately thereafter, the joining surfaces are pressed together and cooled passively or actively, wherein the polymers A and B solidify and form a weld or welded joint. An essential prerequisite for the formation of a mechanically strong weld between the workpieces is the interpenetration and entanglement of polymer chains such that molecular chains of the polymer A partially pass through the interface between the two workpieces and penetrate into the polymer B and vice versa. The interpenetration and entanglement of the polymer chains is often referred to in the literature as interdiffusion. Depending on the temperature, molecular weight, polydispersity and compatibility or miscibility of the polymers A and B, the interdiffusion zone extends over a depth of a few to a few hundred nanometers. With sufficiently good interdiffusion, the welded joint can reach almost the specific strength values of the solid polymers A or B. If one or both thermoplastic polymers A and B are partially crystalline or tend to crystallize, the strength of the welded joint is influenced by crystallization effects and thus indirectly by the cooling rate.

The interdiffusion zone of thermal welds of polymers has been the subject of numerous scientific investigations, although the relationship between their microstructure and mechanical strength has not been fully elucidated to this day.

As used herein, the term "thermal bond" or "thermal seal" as used herein means a bond made by welding two materials comprising a substantial proportion of thermoplastic polymers. The compound can be formed purely cohesively. In order to improve the connection, a casting of undercut sections can additionally take place, so that the cohesive connection is supplemented by a form-fitting component.

According to the invention thermosetting thermosetting binders are used for the wood fiber molding material. In addition, it is provided that the first hot melt adhesive - and optionally the second hot melt adhesive - is equipped with a reactive crosslinking component and thus also has thermosetting character. For this reason, the term "thermal adhesive bond" or "thermal weld layer" is used instead of "thermoplastic adhesive bond" or "thermoplastic weld layer".

As in the case of welding of thermoplastic materials, an interdiffusion zone likewise forms in the method according to the invention, in which polymer chains of the thermoplastic components of the binder of the wood fiber molding material on the one hand and the attachment or the first hot melt adhesive, on the other hand, penetrate.

The melting temperature of the polymeric materials used in the context of this invention is determined by means of dynamic difference calorimetry (DDK or DSC for differential scanning calorimetry). The method of DDK according to DIN 53765 respectively. ISO 11357-3 is known to those skilled in plastics processing and is carried out, for example, with a calorimeter of the type "DSC 1" Mettler-Toledo. Here, two identical crucibles are arranged with a diameter of about 5 mm in a homogeneously heated furnace chamber. In one of the crucibles, a weighed amount of 10 to 20 mg of the polymer resin to be analyzed or the mixture of polymer resins is placed; the other crucible remains empty and serves as a reference. The crucibles are arranged on brackets which are equipped with highly sensitive temperature sensors. The DDK analysis consists of one or two runs in which the two crucibles and the sample to be examined are each heated under inert gas (for example nitrogen) from 0 to 220 ° C and cooled again. The heating and cooling takes place according to DIN 53765-A-20 evenly at a rate of 20 Kelvin / min. During the two runs, the difference in the temperatures of the two crucibles is recorded as a function of time or as a function of the oven temperature. The melting temperature corresponds according to DIN 53765 the center of the melting temperature range, which is characterized by a characteristic curve of the differential temperature (peak of the enthalpy of fusion).

The decorative part is formed as a flat textile-like mat and comprises at least one decorative layer, which is referred to below as a visual position, and optionally further functional layers, in particular a padding layer and / or a layer of a second hotmelt adhesive.

Preferably, the layer of vision consists of a knitted or woven fabric of natural or synthetic fibers or mixtures thereof. In particular, the visual position is a layer of carpet, velor, printed film, thermoplastic polyolefin film (TPO film), polyvinyl chloride film (PVC film), polyester film (PET film), leather or artificial leather. In particular, the visible layer consists of a non-woven fabric of polypropylene (PP) or a mixture of polypropylene and polyethersulfone (PES). Polymers optionally used for the visual position are selected from the group consisting of polyester, polyethylene, polyterephthalate, polyacetate, polyolefin, such as polypropylene or polyvinyl chloride, or copolymers of the above materials.

The optional padding layer is made of a resilient material, preferably selected from the group consisting of natural and synthetic elastomers, foamed polymers, nonwoven webs of natural or synthetic fibers or blends thereof, and synthetic filament spacer fabrics.

In a further embodiment, the decorative part also comprises an insulating layer, which is arranged adjacent to the cushion layer and opposite the viewing position. The insulating layer has the task to protect the material of the padding layer from thermal damage during hot pressing of the wood fiber molding material. Preferably, the insulating layer is made of a nonwoven fabric of natural or synthetic fibers or mixtures thereof.

Advantageously, the visual position, the optional cushion layer and the optional insulating layer are selectively connected to one another in a line-shaped or flat manner by gluing, sewing or laminating.

In advantageous developments of the invention, the attachment parts and the decorative parts are connected to the carrier by means of a first hotmelt adhesive or by means of a second hotmelt adhesive, wherein the first and second hotmelt adhesives may be different from one another. It can also find the same Schmezklebstoff use. Hotmelt adhesives are based on thermoplastic polymers. In their application, they must be heated to a temperature in the range of about 50 ° C above the softening temperature of the thermoplastic base polymer. As a result of the heating, the viscosity of the thermoplastic base polymer is reduced in such a way that it wets the joining surfaces to be bonded and optionally penetrates into pores and depressions in the joining surfaces.

The thermoplastic base polymers for the first and second hotmelt adhesives are selected in particular from the following list: Thermoplastic base polymer Application / softening Polyethylene (PE) 140 to 200 degrees Celsius amorphous polyalphaolefins (APAO) around 170 degrees Celsius Ethylene Vinyl Acetate Copolymers (EVAC) around 150 degrees Celsius Polyester elastomers (TPE-E) 65 to 150 degrees Celsius Copolyamide elastomers (TPA-E) around 130 degrees Celsius Vinylpyrrolidone / vinyl acetate copolymers (water soluble) around 130 degrees Celsius

The first and second hot melt adhesives may independently contain one or more of the above base polymers.

In expedient embodiments of the invention, the first and / or the second hotmelt adhesive are designed as reactive hotmelt adhesive. The reactive hot melt adhesives provided according to the invention are preferably based on polyurethanes which are provided with isocyanate groups. Under the Influence of atmospheric moisture and in particular of water vapor which is produced during the hot pressing of the wood fiber molding material due to the residual moisture of the wood fibers, the isocyanate groups cause crosslinking of the polyurethane molecular chains. Since the crosslinking of the polyurethane molecular chains is not resolved by reheating, reactive polyurethane-based hot melt adhesives are also referred to as thermoset hot melt adhesives.

• • Bereitstellen eines mattenförmigen Holzfaserformstoffes, der ein thermisch härtbares Bindemittel enthält;
• • Bereitstellen eines Anbauteils, das wenigstens abschnittweise mit einem Schmelzklebstoff beschichtet ist und/oder aus einem thermoplastischen Werkstoff besteht;
• • Bereitstellen eines temperierbaren, zwei- oder mehrteiligen Presswerkzeugs, umfassend eine erste und zweite Werkzeughälfte;
• • Anordnen der Anbauteile in der ersten Werkzeughälfte;
• • Einlegen des Holzfaserformstoffs in die erste Werkzeughälfte mit den darin angeordneten Anbauteilen;
• • Schließen des Presswerkzeugs durch Zusammenführen der beiden Werkzeughäften; und
• • Verpressen des Holzfaserformstoffs bei Temperaturen im Bereich von 140 bis 230 Grad Celsius zu einem Träger, wobei die Anbauteile mit dem Träger kraftschlüssig verbunden werden.

According to a further aspect of the invention, a method is provided, comprising the steps:

• • providing a mat-shaped wood fiber molding material containing a thermally curable binder;
• • Providing an attachment which is at least partially coated with a hot melt adhesive and / or consists of a thermoplastic material;
• • providing a temperature-controlled, two-part or multi-part pressing tool, comprising a first and second mold half;
• • arranging the attachments in the first mold half;
• • inserting the wood fiber molding material into the first mold half with the attachments arranged therein;
• Closing the pressing tool by merging the two tooling forces; and
• • Pressing the wood fiber molding material at temperatures in the range of 140 to 230 degrees Celsius to a carrier, wherein the attachments are positively connected to the carrier.

• • der Holzfaserformstoff bei Temperaturen im Bereich von 140 bis 170 verpresst wird;
• • ein Dekorteils, welches eine Sichtlage aus einem textilen Material oder einer Kunststofffolie aufweist und gegebenenfalls mit einem weiteren Schmelzklebstoff beschichtet sind, vor dem Schließen des Presswerkzeugs auf dem Holzfaserformstoff angeordnet und mit dem Holzfaserformstoff verpresst und verbunden werden;
• • beim Verpressen des Holzfaserformstoffs die erste Werkzeughälfte auf eine um 20 bis 50°C niedrigere Temperatur als die zweite Werkzeughälfte temperiert wird;
• • der Holzfaserformstoff in zwei Schritten verpresst wird, wobei das Presswerkzeug zwischen dem ersten und zweiten Schritt geöffnet wird, so dass gasförmige Komponenten, wie Wasserdampf entweichen können; und/oder
• • das Presswerkzeug Kühlvorrichtungen zum Kühlen der Anbauteile umfasst und die Anbauteile beim Verpressen des Holzfaserformstoffes partiell auf Temperaturen im Bereich von 20 bis 140 Grad Celsius temperiert werden.

Advantageous developments of the method according to the invention are characterized in that:

• • the wood fiber molding material is pressed at temperatures in the range of 140 to 170;
• • a decorative part, which has a visible layer of a textile material or a plastic film and optionally coated with a further hot melt adhesive, are arranged before closing the pressing tool on the wood fiber molding material and pressed with the wood fiber molding material and connected;
• • When pressing the wood fiber molding material, the first mold half is tempered to a temperature 20 to 50 ° C lower than the second mold half;
• • The wood fiber molding material is compressed in two steps, wherein the pressing tool is opened between the first and second step, so that gaseous components, such as water vapor can escape; and or
• • The pressing tool comprises cooling devices for cooling the attachments and the attachments are partially tempered to temperatures in the range of 20 to 140 degrees Celsius when pressing the wood fiber molding material.

A further object of the invention is to provide a device which allows to hot compress carriers for moldings of the type described above together with attachments and in this case to temper the attachments separately. This object is achieved by a two-part or multi-part pressing tool having a first and second mold half and heaters for heating the first and second mold halves and one or more cooling devices for partially cooling the first mold half.

• • ein oder mehrere Bereiche der ersten Werkzeughälfte Kanäle zum Durchleiten eines Kühlmittels, wie z. B. eines Kühlfluides umfassen, wobei die Kanäle vorzugsweise mit einem Wärmetauscher oder mit einer Kühlmittelversorgung verbunden sind; und/oder
• • die erste Werkzeughälfte eine Grundform und einen oder mehrere Einsätze umfasst und die Kanäle für das Kühlmittelfluid in den Einsätzen angeordnet sind.

Advantageous developments of the pressing tool according to the invention are characterized in that:

• • one or more areas of the first mold half channels for passing a coolant, such. B. a cooling fluid, wherein the channels are preferably connected to a heat exchanger or with a coolant supply; and or
• • the first mold half comprises a base mold and one or more inserts, and the coolant fluid channels are disposed in the inserts.

The first and second half-molds are each equipped with one or more mold cavities, wherein the at least one mold cavity of the first mold half the contour of the mounting side of the molding and the at least one mold cavity of the second mold half map or define the contour of the visible side of the molding. The mold cavity of the first mold half includes receptacles or inserts with fixtures for the attachments. Suitably, the receptacles are formed as concave recesses with a substantially cylindrical or hemispherical shape. In one embodiment of the invention, the wall of the receptacles is equipped with projections that hold the respective attachment. In an alternative embodiment of the invention, the inner contour of a receptacle essentially corresponds to the shape of the attachment.

Basically, the recesses are configured such that the attachments are stored therein stable and can not tilt by the force acting on the attachment during hot pressing of the molding force.

In an advantageous development of the invention, the receptacles are dimensioned such that the provided for connection to the molding joining surfaces of the attachments by 0.06 to 1.0 mm, preferably by 0.08 to 0.4 mm and in particular by 0.1 to 0.3 mm above the surface of the mold cavity surrounding the receptacle. This ensures that during hot pressing of the molded part between the respective attachment and the molding a substantially gap-free and void-free thermal welding layer is formed.

The invention will be explained in more detail with reference to figures. They show schematically:

1 a perspective view of an attachment;

2 a sectional view of a pressing tool.

1 shows an exemplary, by injection molding of a thermoplastic material, such as polypropylene manufactured, one-piece attachment 10 , The attachment 10 is substantially planar and has a first and second surface 11 respectively 12 on, with the second surface 12 , Is intended to be connected non-positively by means of a thermal welding layer with the support of the molding. On the first surface 11 are holders ( 13 . 14 ), which are used to attach the molding to the bodywork or a door frame of a vehicle. The areal trained part of the attachment 10 reinforces and stiffens the molding.

2 shows a sectional view of a part of a particularly suitable for the production of moldings according to the invention pressing tool with a first and second mold cavity 21 respectively 23 and a fiber molding mat 2 or a hot pressed from fiber molding carrier 3 , Next to or in the first mold nest 21 is an assignment 22 arranged, in which an attachment 10 is inserted. The first and second mold nest 21 and 23 are with recesses, channels, holes or slots 21 ' respectively 23 ' for passing a heated to a temperature of 140 to 230 ° C fluid. The use is analogous 22 with recesses, channels, holes or slots 22 ' provided by which a cooling fluid, such as water is passed to the use of the 22 facing surface of the attachment 10 to a temperature in the range of 20 to 140 ° C to temper. In contrast, which is the fiber molding material 2 or the carrier 3 facing surface of the attachment 10 heated during hot pressing to a temperature which is only slightly lower than the temperature to which the fiber molding material 2 or carrier 3 through the second mold nest 23 is heated.

The first mold nest 21 is appropriate on a support plate 20 fixed; the same applies to the second mold nest 23 (in 2 Not shown).

In an advantageous embodiment of the pressing tool according to the invention, the carrier plate 20 , as well as the first form nest if necessary 21 and the use 22 mechanical devices that allow the use 22 relative to the first mold nest 21 align so that the the fiber molding material 2 or carrier 3 facing surfaces of the mold cavity 21 and one in the insert 22 inserted attachment 10 essentially abut one another without gaps and form a continuous, edge-free transition.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited non-patent literature

• DIN 53765 [0047]
• ISO 11357-3 [0047]
• DIN 53765-A-20 [0047]
• DIN 53765 [0047]

Claims (15)

Molded part, comprising a support of hot-pressed, a crosslinked binder containing wood fiber molding material and at least one attachment which is at least partially coated with a hot melt adhesive and / or consists of a thermoplastic material, characterized in that the at least one attachment by a thermal welding layer with the Carrier are in particular positively connected and contains the thermal welding layer crosslinked binder and hot melt adhesive and / or crosslinked binder and thermoplastic material. Molding according to claim 1, characterized in that the molded part comprises at least one decorative part connected to the carrier with a visible layer of a textile material or a plastic film. Molding according to claim 1 or 2, characterized in that the binder has a curing temperature of 140 to 200 degrees Celsius. Molding according to one or more of claims 1 to 3, characterized in that the thermoplastic material has a softening temperature of 140 degrees Celsius to 180 degrees Celsius. Molding according to one or more of claims 1 to 4, characterized in that the first hot melt adhesive has a softening temperature of 80 degrees Celsius to 160 degrees Celsius. Molding according to one or more of claims 2 to 5, characterized in that the decorative part is connected by means of another hot melt adhesive having a softening temperature of 80 to 180 degrees Celsius with the carrier. Method for producing a molded part, comprising the steps: • providing a mat-shaped wood fiber molding material containing a thermally curable binder; Providing at least one fixture which is at least partially coated with a hot melt adhesive and / or consists of a thermoplastic material to form the weld layer containing cross-linked binder and hot melt adhesive and / or cross-linked binder and thermoplastic material; • providing a temperature-controlled, two-part or multi-part pressing tool, comprising a first and second mold half; • the attachments are placed in the first mold half; • the wood fiber molding material is placed in the first mold half with the attachments arranged therein; • The pressing tool is closed by merging the two mold halves; and • The wood fiber molding material is pressed at temperatures ranging from 140 to 230 degrees Celsius to a carrier, wherein the attachments are connected to the carrier in particular non-positively. A method according to claim 7, characterized in that the wood fiber molding material is pressed at temperatures in the range of 140 to 170 degrees Celsius. A method according to claim 7 or 8, characterized in that a decorative part, which has a visible layer of a textile material or a plastic film and optionally coated with a further hot melt adhesive, arranged before closing the pressing tool on the wood fiber molding material and pressed with the wood fiber molding material and connect becomes. A method according to claim 9, characterized in that during pressing of the wood fiber molding material, the first mold half is tempered to a 20 to 50 degrees Celsius lower temperature than the second mold half. Method according to one or more of claims 7 to 10, characterized in that the wood fiber molding material is compressed in two steps, wherein the pressing tool between the first and second step is opened, so that gaseous components, such as water vapor can escape. Method according to one or more of claims 7 to 11, characterized in that the pressing tool comprises cooling devices for cooling the attachments and the attachments are partially tempered during pressing of the wood fiber molding material to temperatures in the range of 20 to 140 degrees Celsius. A two- or more-part pressing tool having first and second mold halves and heaters for heating the first and second mold halves, characterized in that the pressing tool comprises one or more cooling devices for partially cooling the first mold half. Press tool according to claim 13, characterized in that one or more areas of the first mold half channels for passing a coolant, in particular a cooling fluid, wherein the channels are preferably connected to a heat exchanger or with a cooling water supply. Press tool according to claim 13 or 14, characterized in that the first mold half comprises a basic mold and one or more inserts and the channels for the coolant are arranged in the inserts.

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