DE19956765A1 - Thin-walled and profiled three-dimensional body for door panels etc is prepared from mixture of wood and/or wood particles with bonding agent molded by heat and pressure - Google Patents

Abstract

The thin-walled and three-dimensional shaped body consists of a mixture of wood and/or wood particles and heat-setting powder bonding agent at a rate of 10-15% of the material. The mean particle size of the wood or wood particles is 0.1-0.6 mm. The mixture is shaped by heat and pressure. At least one surface of the shaped body is cladded with a thin-walled plastic film or a biodegradable varnish. The wood or wood particles have a generally spherical shape, with a mean particle size of preferably 0.1-0.3 mm. The wood or wood particles are taken from wood chips or unsoiled or ecologically treated chip particles, reduced by a ring blade cutter. The preferably ratio of bonding agent is 12-14% of the mixture. The shaping is through a one-piece or multi-part die, at a pressure of 20-45 bar and a hardening temp. of 140-180 deg C. The die forming can be in a stage press, or a single press with a number of rotating and heated dies. The surface of the shaped body is cladded with a plastics film with a thickness of 0.1-0.5 mm. The film is embossed and/or given a wood grain effect. The film is applied by a vacuum press. The surface can be coated with a biodegradable varnish. The bonding agent powder has a particle size of 10 mu m to 0.6 mm. Air channels (9) are fitted between the covering and intermediate layers and/or between adjacent intermediate layers. Two panels can be bonded together with perforated paper webs. An Independent claim is included for a production process where the panel with the intermediate layer are pressed together in an unheated press at the bonding station. The bonding station has a drilling to develop an under pressure between the covering panel (1), the bonding unit (5) and the intermediate layer (s) (8).

Description

The invention relates to a thin-walled, three-dimensionally shaped semi-finished or finished part for use as a cover plate (molded deck) in industrial door production, in furniture construction and comparable areas, especially for use in strongly profiled sheets of Profile doors for indoor and outdoor use and a process for their manufacture.

Known door leaves of wooden doors consist of wood-based panels or solid wood frame that surrounds the insert and holds cover plates on both sides. The deposit will formed by heat or sound-insulating materials or panels (e.g. chipboard). Veneer, wood fiber or chipboard or two crosswise serve as cover plates laminated veneer layers.

For the production of strongly profiled door leaves on industrially manufactured doors on CNC controlled processing machines grooves, profiles or other design elements milled from solid wood or chipboard. An alternative possibility is in subsequent application of design elements such as profile strips, cassettes, etc. The decorative design elements are screwed to the cover plate, doweled or glued flush.

Both methods have significant shortcomings. Subsequent machining complete door leaf caused by the attainable working speeds of the used end mill or end mill significant manufacturing costs and also extends the Lead time of the products. In addition, correspondingly large milling equipment or machining centers for the complete machining of large door panels be used.

During the subsequent assembly or joining of form-forming elements, the In contrast, a higher installation effort. Also, the usually glued positioned design elements and until the setting or hardening of the Adhesive are kept in this forced position. Taking into account economy  Minimum number of pieces, therefore, several devices must be provided redundantly in order to be able to realize the technologically related holding and setting times. In addition, from DE 297 19 080 U1 house doors with a frame made of wood fiber material known in which the entire frame made of phenol-impregnated high-density wood fiber material consists. The visible door leaves consist of either solid wood or one phenol-soaked layered paper with a decorative outside. The continuous film is not rigid in itself and only allows a flat coating of the underlying one Under door leaves or the frame. A distinctive three-dimensional shape the visible outer surface of the door wing is not feasible.

The object of the invention is to eliminate the disadvantages of the known prior art and a thin-walled, three-dimensionally shaped semi-finished or finished part for use as a cover plate (form deck) in door production, in furniture construction, and comparable Areas to propose that is industrially producible in large numbers and one strongly profiled design of the visible surface allows, as in particular handcrafted solid wood doors is known. In addition, under ecological Aspects are used in particular for the semi-finished or finished part materials, that are recyclable and in particular as waste products in woodworking and processing attack. In addition, a method is to be proposed with which strongly profiled doors can be manufactured economically.

According to the invention the object is achieved by the features of the main claim. Further developments of the invention are preferably the subject of the dependent claims.

A door leaf according to the invention consists of a frame or edge band made of wood, Wooden materials, plastic and / or metal. The frame as a support structure takes the Intermediate layers and the outer, thin-walled, three-dimensionally shaped Form decks on. The molded decks are glued to the frame or to the body Edge and / or the intermediate layers connected.

The mold decks are made from a mixture of wood and / or wood material particles and a heat-reactive, powdery binder, preferably a phenolic resin,  manufactured. The grain size of the wood or wood material particles is 0.1 mm to 0.6 mm. The mold decks are created by primitive shaping of the mixture in mold dies with the supply of Pressure and thermal energy.

The outer, visible top surface of the molded deck is thin-walled Laminated plastic film. On the one hand, the film serves to protect the door leaf penetrating moisture and also allows easier cleaning of the surface especially with heavily used doors in public buildings, offices, etc. In addition the 0.1 mm to 0.5 mm thick film forms the optical conclusion of the underlying one Molded part. As a result, wood or wood material particles or mixtures thereof can be used Manufacture of the molded part to be used, which comes from different starting plants fabrics, e.g. B. there are chips or chip fragments of ecologically prepared chipboard, because the laminated film covers the surface of the mold deck.

On the other hand, the film, which is elastic and easy to form when heated, allows for Polyolefins, polypropylene or polyvinyl chloride when processed in known 3-D Vacuum presses apply evenly to the surface of the molded part, even when strong structured surfaces.

This is achieved through the use of structured, colored or decorated foils The product also has higher aesthetic properties.

In contrast to the alternatively possible coating of the surface of the molded parts by means of water-soluble paints in the immersion or spray process is characterized by the lamination of a Foil from a higher work productivity. This is not the case when applying one Paint system necessary, multiple sanding of the strongly profiled surfaces of the mold deck. In addition, there are no technological auxiliary processes and the use of complex technology, which are essential for conventional coloring (use of paint spray booths, Technologically determined holding times for drying and venting the paint system, intermediate storage until the paint has hardened / set).

Another advantage of using a film made of PVC, PP or PO as a surface finish of the molded part is that the necessary adhesive is laminated onto the film can. A hot melt adhesive is preferably used as the adhesive. The one so prepared The film can be rolled up, stored in the glued state almost indefinitely and is easy to use to process.  

Another major advantage is that the gluing is usually strong structured surface of the molded part can be omitted.

The preferably used 3-D films made of polypropylene or PVC have one likewise preferred the grain of a real wood veneer.

In addition to the technological advantages of using foils for the surfaces Completion of the mold decks (quick processability, good availability, no technology auxiliary times for drying / setting, such as when using coating systems) The films are also characterized by their high abrasion resistance. In addition to the good Resistance to temperature fluctuations and weather influences guarantee the used foils a high durability and functionality of the doors made in this way. Due to the design possibilities, these correspond to industrially manufactured ones Doors also meet high aesthetic requirements with reduced manufacturing costs.

Processing the mixture of wood and / or wood material particles and phenolic resin Containing binder takes place in one or more part, heatable press dies. After this This is done in a dosed filling of the die forms with the wood particle-binder mixture Archetype of the decks depending on the respective design with a pressure of about 20 bar to 45 bar. After reaching the final pressure, the preheated dies heated up.

The hardening temperature in the dies is approx. 140 ° C to 180 ° C. The dwell time of the pressed mold decks at the aforementioned curing temperature is approximately 120-300 Seconds. After opening the die molds, the pressed mold decks are finished preferably removed from the mold by pneumatic means and allowed to cool route abandoned.

Common presses are used as machine tools; especially floor presses or single presses with rotating, heatable dies.

By using a quasi-homogeneous mixture of wood particles and powder Phenolic resin can produce extremely thin-walled molded parts with sufficient strength are manufactured. The average wall thickness of a molded part is advantageously 4 mm to 8 mm. The mixture of wood particles mixed with a phenolic resin-containing binder exists preferably from wood or wood fiber chips with a particle size between 0.1 mm and  0.6 mm. Chip particles are preferably used, the surface shape of which is almost is spherical. Such chip forms are u. a. generates larger when crushed Chips used as technological waste in sawmills in the manufacture of boards, planks or squared timber. These chips have an edge length of up to 15 mm. By further processing in an impact finisher (knife ring chipper) chip form particles of the desired size and shape. In subsequent screening processes Chips with a nominal diameter <0.6 mm and <0.1 mm eliminated.

The remaining wood particle mixture points in connection with the one used phenolic resin-containing binder ideal flow properties during the subsequent pressing of the Wood particle-binder mixture in the heated press die. So it is possible Original form decks, which are characterized by minimal edge radii. The usage the wood particle mixture also guarantees an even formation of flat surfaces. The smaller chip particle elements with a nominal diameter of 0.1 mm are used up to 0.2 mm in connection with the binder particles as filler, which on the surface the form deck for an even and homogeneous finish.

Wood or wood material particles with a nominal diameter of are therefore preferred 0.1 mm to 0.3 mm used, the processing of which is slightly more complex, the Mixture in connection with the powdery binder but best flow and Offers creep properties and thus optimal formability of the semi-finished product or Precast part allows. A pulverized is preferred as the heat-reactive binder Phenolic resin with a grain size of 10 µm to 0.6 mm is used. It will be the same moderate filling of the die forms without signs of segregation and at the same time a good one Creep behavior of the mixture realized.

In addition to the use of natural chips, which is a cost-effective waste product Sawmills or other wood processing companies can be obtained in addition, the possibility of using chips from recyclable wood, e.g. B. old wood or from used wood materials, such as. B. chipboard.

With known technologies, chipboards can be mechanically shredded or in fluids Systems are broken down into their components. After the disposal of any pollutants (e.g. binding of formaldehyde with known formaldehyde scavengers) become the chips  dried and brought to the desired nominal size in a hammer mill. By Subsequent screening in several stages is analogous to a wood-based material mixture won, whose quasi-spherical chip elements a preferred nominal diameter have between 0.1 mm and 0.3 to 0.6 mm.

When using shavings from natural wood for the production of the wood pre-drying of the delivered chips may be necessary. The Wood chips must also be free of any contamination and foreign matter (Bark, coating material, etc.).

All heat-reactive binders or adhesives can be used as binders, which are suitable for the production of wood-based materials. The binder portion of the powdered phenolic resin is preferably 12% to 14% of the total amount used Wood particle-binder mixture. A powdery binder is preferred Phenolic resin used, for example, under the trade name Plastaresin 7280 Plasta Erkner is distributed. In addition to the phenolic resin-containing binders alternatively known, rotten adhesives or binders can be used, e.g. B. the starch-based product SCONACELL (A). The stake continues thermally reactivatable binders, e.g. B. on the basis of PVAC possible.

Thanks to the good flow properties of the wood particle-binder mixture during pressing, the not only can strongly profiled mold decks improve with decreasing particle size getting produced. Another advantage is the possibility of the average wall thickness in To reduce compared to solid wood doors to 4.5 mm to 5.5 mm. So they point out manufactured shell-like molded decks mechanical properties of a lightweight element on.

Another advantage is that due to the good plasticity and the creeping tendency of the wood particle-binder mixture also have different wall thicknesses half of the mold deck can be produced without the inherent strength and adversely affect the closed surface of the mold deck become.  

The thin-walled molded decks are used in particular as a decorative exterior finish Doors, furniture or decorative items are used.

The preferred use of the form decks in the production of style doors for the interior or Outside is described below using several examples:

Due to the good flow properties of the wood particle-binder mixture, too large door decks with an average wall thickness between 5 and 8 mm are manufactured, whose external dimensions are up to 2200 × 1000 mm.

Fig. 1 shows an example of such a door leaf of a simple room door, the visible surface of which is formed by a continuous molded deck.

Fig. 2 shows a broken-away sectional view of the contour of the shape deck 1 between the edge 2 and the middle part 3rd The different wall thicknesses and the filigree, e.g. T. sharp-edged profiles of the mold deck 1 .

FIG. 3 shows three further, exemplary shapes of a door leaf which are manufactured using a plurality of molding decks.

Form A shows a door leaf with a single rebate, the visible surface of which is inserted from two Cassette decks exist. Forms B and C also show elaborately designed special doors Double and triple fold for use indoors or outdoors.

FIG. 4 shows a stylized sectional view of the single folding door according to FIG. 3 A. A 32 mm thick chipboard is used as the central layer 4 . The edge band consists of a 32 × 34.5 mm square timber made of knot-free solid wood. The two outer, bowl-shaped mold decks 1 have 6 throat-shaped recesses in the profiling area. The two mold decks are connected to the underlying middle layer using known adhesive systems such as white glue or urea glue. The molding decks 1 are bonded to the middle or intermediate layer 4 over the entire surface.

The decks are advantageous with the liner in an unheated press especially compressed in the area of the edge band. On one in the edge band  a vacuum hose coming from a central pump, whereby the decks are pressed onto the edge band and intermediate layer. Possibly Existing assembly openings are closed with conventional self-adhesive tape. After that the press can already be opened and the compact can be removed with the hose attached and be stored until the adhesive has hardened. The advantage of this variant lies in extremely short clamping times in the press and in the possible waiver of process heat me to accelerate adhesive curing.

After the door leaf is prepared as a sandwich element, the final finishing is carried out by laminating the surface with a 0.3 mm thick polypropylene film. The film 7 is glued with a JOWAPUR 15000 PUR contact adhesive from JOWAT. The glued PP film is applied to the surface of the mold decks on known membrane presses. The PP film covers the entire surface of the door leaf. The fold area is foiled on a separate press. Due to the closed film up to the fold area, moisture penetration is effectively prevented.

Fig. 5 shows in a stylized representation a cross section through a double rebate door according to Fig. 3, Figure C. This massive door has improved sound insulation properties and is characterized by a minimized heat transfer. Due to the constructive design, this door can be used as an apartment door or front door.

The double rebate door consists of a panel with three intermediate layers. The two outer ones Intermediate layers consist of a 16 mm thick chipboard. The middle liner consists of a 16 mm thick polyurethane foam panel. This also creates one excellent thermal insulation enables.

The three intermediate layers are connected to one another by point-by-point bonding with known urea or white glue. This will have better acoustic properties of the door leaf realized. This means that sufficient shavings can be created due to the partial bonding are transmitted, which inevitably occur when moving the door and at full-surface bonding would lead to increased noise.  

In an alternative embodiment, two molded door decks are used alone Polyurethane foam connected by foaming. The adhesive connection Formdeck PUR foam is made up of two inserted and attached to the form decks, perforated paper webs limited to the area of this perforation. This will make one Improvement in sound insulation achieved. Furthermore, an easier separation of the Form decks of the PUR foam core when required and disposal subsequent recycling of the components possible.

In the area of the edge band, the door leaf has air channels 9 which lead to the edge zone between the inner wall of the mold deck 1 and the outer wall of the adjacent intermediate layer 8 . On the one hand, air can escape through the channels during the new production of the doors, which air has formed in the edge area between the mold deck and the adjacent intermediate layer. The outer openings of the air channels 9 are finally closed with the edge banding foil (not shown in the picture) or with a synthetic resin in order to reliably prevent the ingress of air humidity or splash water.

When the door is subsequently recycled, the air channels 9 are pierced and pressurized with air, so that the outer mold decks 1 can be separated over the entire area from the intermediate layer 8 below.

Especially when the form decks are glued point by point to the intermediate layers the compressed air very quickly and safely to tear off the mold decks from the intermediate layers and finally from part of the edge band. After complete separation of the Components can be sorted or sorted and reprocessed take place.

The intermediate layers and the edge band are recycled using known methods. The separated form decks with the plastic film laminated thereon are z. B. in one Cross beater mill pre-crushed and in a hammer mill to a grain size of <= 0.8 mm brought. Up to 10% of this product is used as a raw material the wood particles used and mixed to new form decks as described is working. No additional, possibly disruptive substances are introduced, and the elastomechanical and surface properties of the molded decks produced in this way practically not changed. The recycling cycle is now closed.  

The phenolic resin powder as a binder enables a good bond even in the Particles wetted with phenolic resin in the first cycle. The particles from the recycled, formerly laminated plastic film itself acts as a thermoplastic binder. By the advantageous particle size of the wood or wood material particle from 0.1 mm to 0.6 mm and the compact, ball-like shape does not occur when the mold decks are recycled Destruction of the slim particles otherwise desired in wood-based materials, but it will produces a recycling product comparable to the raw material. Thus occurs at the Recycling does not lead to "downcycling", but new mold decks with the same Properties such as the recycled mold decks used as the starting material.

Due to the variations in the intermediate layers, the door thickness, the number and shape of the Seals of the folds as well as the fittings and locking mechanisms can be found under Use of the form decks not only for room and apartment entrance doors, but also Sound insulation, smoke protection, fire protection, security and radiation protection doors manufactured become.

A particular advantage is the possibility of using a modular principle to produce cost-effective system doors for objects that look the same Characterize molded decks with different usage properties. So z. B. at the Design of a doctor's office, the burglar-resistant entrance door, the door to the X-ray room, the soundproof door to the treatment and meeting room and the fire Protective door of the storage room have the same external design elements as that simple room doors from adjoining rooms.

When manufacturing a fire-retardant door, for example, is used as an additional intermediate layer an approximately 2 mm thick steel sheet and a 20 mm to 40 mm thick plasterboard, e.g. B. FERMACELL, integrated in the sandwich composite of the door leaf. The mechanical These panels are connected to the adjoining intermediate layers of chipboard by full-surface gluing with an adhesive system made of phenol-formaldehyde resin.

When manufacturing radiation protection doors, a thin-walled, approximately 3 mm thick Lead foil embedded from the adjacent intermediate layers of chipboard.

In the manufacture of soundproof doors, 2-4 intermediate layers of approximately 16 mm thick Particle boards are connected to one another by stapling or gluing.  

The variety of shapes in the manufacture of differently designed surfaces on doors to increase the press dies for the primary shaping of the mold decks after a Modular principle selected. This is a combination of different form elements possible while reducing the production costs for the die forms.

Thanks to the variable arrangement of the different die shapes on the press table can with a comparatively small number of basic forms a variety of Form designs are made possible.

Intermediate layers are used in door production in addition to the full chip already mentioned plates also used paper honeycomb or chipboard.

In a preferred embodiment, a soundproofing door is used as an intermediate layer Chipboard with horizontal arrangement of the tubes used. The tubes are with fine-grained minerals, preferably filled with sand. This makes a high one Soundproofing enabled. The larger mass of the door is also considered by the customer Expression of solidity and reliability of the door system understood.

The edges of the doors are preferably made of knot- and tension-free straight wood, made of MDF material, veneer plywood or other known materials if also used in conjunction with each other.

With the same manufacturing technology, molded decks for furniture or Furnishings are made.

As an alternative to the surface lamination of the doors or furnishings with a Depending on the customer's requirements, plastic film can also be used in known dipping or coating systems Spraying methods are applied.

In addition to the excellent manufacturing technology and design options, the derive from the good flow properties of the wood particle-binder mixture used result, the doors and furnishings manufactured according to the invention have a high durability and full recyclability. Thus, after the normative service life a material-appropriate separation of the product components and their recycling possible without any problems.  

Overview of reference symbols used

1

Form deck

2nd

edge

3rd

Middle section

4th

Middle position

5

Edge band

6

Profiling area

7

foil

8th

Liner

9

Air duct

Claims (22)

1. Thin-walled, three-dimensionally shaped semi-finished or finished part for use as a cover plate in furniture construction, in door manufacturing and comparable areas, in particular for use in strongly profiled sheets of profile doors for indoor and outdoor use,
consisting of a mixture of wood and / or wood material particles and a powdery, heat-reactive binder with a mass fraction of the mixture of 10% to 15%,
the average grain size of the wood or wood material particles being 0.1 mm to 0.6 mm,
and the cohesion of the mixture is created through primary shaping with the application of pressure and heat
and that at least one top surface of the shaped semi-finished or finished part is coated with a thin-walled plastic film or a biodegradable paint system. 2. semi-finished or finished part according to claim 1, characterized, that the essentially spherical wood or wood-based material particles have a have average grain size of 0.1 mm to 0.3 mm. 3. semi-finished or finished part according to claim 1 or 2, characterized, that the wood or wood material particles from wood chips or unloaded or Ecologically prepared particle board particles are made using a ring knife chippers are crushed.   4. semi-finished or finished part according to one of claims 1 to 3, characterized, that the proportion of the powdery, heat-reactive binder in the mixture is 12% is up to 14%. 5. semi-finished or finished part according to claim 1, characterized, that the original shaping of the mixture in a single or multi-part die in one Press pressure from 20 bar to 45 bar and a hardening temperature in the die of 140 ° C up to 180 ° C. 6. semi-finished or finished part according to claim 5, characterized, that the original shaping of the mixture in a single or multi-part die on one Floor press is carried out. 7. semi-finished or finished part according to claim 5, characterized, that the original shaping of the mixture in a single or multi-part die on one Single press with several rotating, heatable die forms. 8. semi-finished or finished part according to claim 1, characterized, that the top surface of the preformed semi-finished or finished part with a 0.1 mm to 0.5 mm thick plastic film is coated.   9. semi-finished or finished part according to claim 1 or 8, characterized, that the plastic film is made of polypropylene. 10. semi-finished or finished part according to claim 1 or 8, characterized, that the plastic film consists of a polyolefin. 11. Semi-finished or finished part according to claim 1 or 8, characterized, that the plastic film is made of polyvinyl chloride. 12. semi-finished or finished part according to one of claims 1 or 8 to 11, characterized, that the plastic film is embossed and / or has a real wood grain. 13. semi-finished or finished part according to claim 1, characterized, that the top surface of the preformed semi-finished or finished part with a biodegradable paint system is coated. 14. semi-finished or finished part according to claim 1, characterized, that the semi-finished or finished part is used as a molded deck of a door leaf.   15. semi-finished or finished part according to claim 1, characterized, that the semi-finished or finished part as a molded deck of a piece of furniture or an interior direction is used. 16. semi-finished or finished part according to claim 1, characterized, that as a heat-reactive binder, a powdered phenolic resin with a grain from 10 µm to 0.6 mm is used. 17. Semi-finished or finished part according to one of claims 1 or 8 to 12, characterized, that the plastic film by means of a vacuum press on the surface of the semi-finished product is applied. 18. semi-finished or finished part according to claim 1 or 14, characterized, that the semi-finished or finished part is used as a molded deck of a system door, the as exterior or interior door, room and entrance door, soundproof door, smoke protection door, Fire protection door, security door and / or radiation protection door can be used. 19. Semi-finished or finished part according to claim 1 or 14, characterized, that between the mold deck and the underlying intermediate layer and / or Air ducts are arranged between adjacent intermediate layers.   20. semi-finished or finished part according to one of claims 1, 14, 15 or 19, characterized, that two mold decks are connected with polyurethane foam, the adhesive Connection of molded deck polyurethane foam through two inlaid and attached to the mold Deck stapled, perforated paper webs on the surface portions of this perforation is limited. 21. Process for producing a thin-walled, three-dimensionally shaped half stuff or finished part according to claim 1, characterized, that the semi-finished or finished part from a mixture of wood and / or woodwork particles with an average grain size of 0.1 mm to 0.3 mm and a powdery, heat-reactive binder with a mass fraction of the mixture of 10% to 15% in a heatable permanent mold under a pressure of 20 bar to 45 bar and at a reaction temperature of 140 ° C to 180 ° C is preformed. 22. A method for producing a thin-walled, three-dimensionally shaped semi-finished or finished part, characterized in that
that the mold decks are pressed together with the intermediate layer, especially in the area of the edge band of an unheated press,
and that at least one bore arranged in the edge band creates a negative pressure between the mold deck, edge band and intermediate layer.