DE102019000610A1 - Mixture of plastic with wood particles - Google Patents

Abstract

According to the invention, mixtures of wood particles and plant particles and plastic are produced in the planetary roller extruder in that the plastic is separately converted into a molten form before it is brought together.

Description

The invention relates to the mixture of plastic with wood particles or other plant particles or the like, hereinafter referred to collectively as wood particles / plant particles. To the extent that only wood or only wood particles are addressed, the wood particle / plant particle includes.

• Formteile, Werkstücke, Blöcke, Tafeln, Folien, Bahnen, Beläge, Rohre, Schläuche, Stäbe, Stangen, Profile, Bänder, Schnüre, Drähte, Borsten, Netze
• Klebstoffe, Lacke, Leime, Kleister, Kitte, Bindemittel
• Farben, Putze, Spachtel, Verguß- und Versiegelungsmassen, Schmelz- und Beschichtungsstoffe, Gele,
• Fäden, Fasern, Garne, Seiden, Stränge, Matten, Vliese, Gewebe

Plastics are used in many different ways

• Molded parts, workpieces, blocks, sheets, foils, sheets, coverings, pipes, hoses, rods, bars, profiles, strips, cords, wires, bristles, nets
• Adhesives, varnishes, glues, glue, putties, binders
• Paints, plasters, spatulas, casting and sealing compounds, melting and coating materials, gels,
• Threads, fibers, yarns, silks, skeins, mats, nonwovens, fabrics

The plastics can consist of monomers and / or of polymers. Often it is a mixture / blends of plastics, whereby there are also mixtures with substances other than plastics. This is especially true for the production of plastic foam.

Extruders are preferred for processing plastics.
The materials used can be melted, mixed or homogenized very advantageously with an extruder, and the proportions of the mixture dispersed in the plastic.

In addition, the feed can be heated or cooled at the same time. For heating or cooling there are cooling lines or heating lines in the extruder jacket and possibly also in central spindles. In addition, the deformation exerted by the extruder spindles on the feed material causes considerable heating.

Very difficult substances can also be mixed in the extruder. The difficult to mix substances include wood and plastic. The wood is fed into the extruder in small particles, where it is coated with the plastic.
In order to effect the wrapping, the plastic must be strongly plasticized. This happens under appropriate heating and under pressure. However, the heat is only very poorly passed on by the wood. In addition, the wood contains a lot of pores.
According to an older proposal, there is a risk that the plastic will be disproportionately pressed into the pores and distributed unevenly and that the wood particles will not be encased on all sides.

The wood-plastic mixture is also called a wood substitute.

Wood is used in various areas. This includes furniture, interior fittings, exhibition stand construction, even automotive linings. In the case of furniture, a distinction must be made between furniture in which the wood is used only as a construction material or as a visible surface.

In upholstered furniture, wood is mostly only used as a construction material. Usually all upholstered furniture has a solid substructure, eg a frame, also called a frame. Seating surfaces, backrests and armrests as well as the feet are optionally mounted in and on the frame. Optionally, the frame also directly forms the seat, backrests and armrests or vice versa. The material from which the frame is made is the construction material.
Traditionally, frames for upholstered furniture are made of wood. Boards and sticks are used. Wood has the advantage that the individual parts can be connected to each other as well as to the upholstery and upholstery by so-called tacking. U-shaped brackets are used for stapling. The clip replaces the upholstery nails from earlier times.

Other furniture shows wood as visible and decorative or decorative surfaces.
The requirements thus given are only partially met by certain rare types of wood. Rare woods are relatively expensive. That is why it has long been state of the art to cut veneers from the rare woods that form the visible surface. Veneers contain thin, foil-like woodcuts. There is a considerable committee when the veneers are to be processed, as the wood has grown.

The mixture of wood particles and plastic creates an advantageous wood substitute.
Instead of wood particles, other shredded plants can also be used. Optionally, an extrudate made of plastic and wood particles and other aggregates is produced, which is foamed or unfoamed. With wood fibers in the extrudate one speaks of a reinforcement. When wood particles are used differently in plastic, wood is called a filler. In the USA, one speaks of a wood substitute if the proportion of wood in the mixture reaches 50% by weight. For example, boards made from a mixture of wood particles and plastic with the specified proportions are common in the USA. The US market accepts this. An example of the mixtures customary in the USA is shown in WO 02 / 103113A ,
The European market only accepts a wood substitute in the visible area if the appearance of the material comes much closer to the wood. This requires 70% or more wood.
However, permanent and flawless outdoor applications with such a material have so far not been achieved.
For the use of other plant components, for example straw, instead of wood particles, the same applies as for wood. Some of the parts of the plants have a lower strength than wood. As far as strength is concerned, this must be taken into account by changing the mixture. Grain meal and crushed hay can also be used as further plant parts.

According to an older proposal, the plastic portion of the extrudate should be reduced as much as possible. The wood content in the extrudate is 60 to 95% by weight, based on the mixture. The optimal plastic content should be added depending on the mixture proportions, the processing and the intended property values of the mixture.

According to the older proposal, the dimensions of the plant particles are determined by the continuity of the particles in the extruder when using conventional extruders. The continuity is determined by the play of the moving extruder parts in the extruder and by the opening width of the nozzle gap. The continuity can be determined based on the known machine data. The permissible dimensions of the plant particles for the respective extruder can then be determined. For safety reasons, the dimensions of the plant particles can be chosen smaller than the continuity described above. This can be done by grinding and / or classification. When grinding, the wood particles are reduced to a desired size. In the classification, a particle mixture is separated by sieving for desired particle sizes.

Alternatively, the continuity of the extruders can be adapted to the desired particle size according to the older proposal. In the case of single-screw extruders and twin-screw extruders, the play between the screws and the surrounding housing is important. The game can be done by building a new extruder or by replacing components, for example by replacing the extruder screw, the nozzle or the bushing in the extruder housing. Contemporary extruders have a socket in the extruder housing in which the screws circulate.
In planetary roller extruders, the play between the toothed parts is important. These are the central spindle, the housing with the internal toothing or the housing bushing with the internal toothing and the planetary spindles. The planetary spindles are easy to replace. However, the central spindle and the internally toothed housing bush or the internally toothed housing can also be replaced.

All extrudable plastics are suitable as plastics, in particular polyethylene (PE), polystyrene (PS), polyurethane (PU) and polypropylene (PP). PE is particularly preferably used.

The adhesion promoters can compensate for a lack of adhesion of plastic with plant particles or with wood particles.
Adhesion promoters form molecular bridges at the interfaces between the substances to be bonded, here the plastic.
If other fillers or reinforcing / reinforcing agents such as glass fibers are used, the adhesion promoters can also have the task of increasing the adhesion to these other substances. Adhesion promoters can be VC (vinyl chloride) copolymers, polymerizable polyesters or vinyl-acrylonitrile-methacrylic acid copolymers, phenolic resins, rubber derivatives or acrylic resins with or without PF (phenol-formaldehyde) or. EP (epoxy) resins.
EVA (ethylene-vinyl acetate copolymers) are also generally known as adhesion promoters.

It may also be sufficient to make the plant particles hydrophobic, i.e. reduce the surface tension.

The plastic is conventionally fed into the extruder as granules with the plant particles and aggregates. Optionally, the granules already contain a mixture of plastic and aggregates.

The moisture can be reduced to any desired level for the extrusion by drying. The humidity setting / degassing can also be carried out in the extruder. It is not always desirable to have a minimal moisture content, but rather a specific moisture content which influences the extrusion process and / or the nature of the extrudate.

• eine sehr hohe Einzugswirkung
• einen sehr guten Druckaufbau.

Up to now, twin screw extruders were considered to be particularly cheap for extrusion because they have:

• a very high feed effect
• a very good pressure build-up.

Extruders can advantageously be composed of different elements or sections of different designs. Therefore it is possible to enter the plasticization zone to use a cheap element there in the design of a twin-screw extruder and to combine this element in other extruder zones with other designs which have advantages there. Thus, a single-screw extruder section can be used in the filling zone, with which a pressure build-up can advantageously be represented. Other sections are better for mixing and homogenization.

The plastic melts under pressure and temperature. In the further course of the feed mixture through the extruder, the mixture is homogenized. For the homogenization zone and dispersion zone, it is advantageous to use extruder elements with a high mixing capacity. These are e.g. Elements with the design of a planetary roller extruder. This element also has a high cooling effect, with which the processing temperature can be controlled very precisely. Depending on the type of plant or type of wood and the plastic, there is a different optimal processing temperature for the melt. The temperature can be, for example, up to 200 degrees Celsius with a maximum residence time (heat exposure period) of 15 minutes. With a shorter duration, the maximum temperature can be higher than with a longer duration.

In the further extrusion, a distinction must be made between extruding non-foamed plastic and extruding foamed plastic.
A certain moisture content may be desired in both extrusion processes.
The residual moisture can serve as a lubricant. The residual moisture can also react chemically. For example, moisture can react with the lignin of the plant particles. Surprisingly, this can result in improved adhesion between wood and plastic. The appropriate moisture / lignin content can be tested by varying the moisture and varying the lignin content. Lignin is also commercially available in liquid form.

If no water / moisture is desired during extrusion, this can be counteracted by drying the plant particles before extrusion. In addition to or instead of drying, the moisture can be removed by degassing after evaporation in the extruder. Degassing can take place immediately after evaporation. This is regularly the case in the plasticization zone. The necessary warming takes place there.
This warming arises from the deformation work during plasticizing and, if necessary, by adding heat. Heat can be supplied, for example, by temperature control in the extruder housing.
If required, the degassing takes place immediately before the extrusion die.
Degassing usually requires that the melt pressure be reduced.
Degassing using two extruders arranged in tandem at the transfer between the two extruders is also known.
The degassing can also take place in an extruder. A desired pressure reduction of the melt can be achieved with various measures, for example by changing the pitch of the screw in the extruder.
For degassing, the melt can also be drawn off from the extruder and passed through a degassing device and returned to the extruder.
Pressure control can be made considerably easier by interposing a melt pump. This also applies to the pressure immediately in front of the extrusion die (tool). Here the pressure can also be evened out by the melt pump, thus improving the quality of the extrudate.
Further degassing options are in the PCT / EP2017 / 1372 described.

The higher the proportion of wood in the mixture, the greater the risk that the material is no longer suitable for outdoor use. The known materials disintegrate after some time due to constant frost / thaw changes. Another disadvantage of the known materials is a disproportionate swelling, which easily leads to great damage or must be taken into account with oversized expansion gaps.
In addition, the wear of the extrusion system increases with the increasing proportion of wood. The wear reduces the economic efficiency of the system.

The PCT / EP2007 / 9140 has therefore taken on the task of improving the production of wood substitutes from a mixture of wood particles or other plant particles. The better wood appearance desired in comparison to the US standard requires wood or plant parts of at least 60% by weight, preferably 65% by weight and more.

After PCT / EP2007 / 9140 A significant process improvement is achieved by a mixture of plastic and wood particles and other plant particles in a planetary roller extruder or planetary roller extruder section.
The application is at the same time opposed to the knowledge that high wood proportions or high plant proportions lead to heavy wear in the planetary roller extruder or planetary roller extruder section provided.

After PCT / EP2007 / 9140 Wear is reduced by plasticizing the plastic at least separately from the wood and optionally also separately from other wear-causing additives in the mixture and then spraying it into the stream of wood particles and by homogenizing and pressing the mixture. The supplements can include: paints, couplers to increase the adhesion between plastic and wood, lubricants to reduce friction in the extruder, water repellents, stabilizers.

In the US6479002B1 is also mentioned, among other things, that the plastic is melted separately from wood particles and other plant particles and then fed to the wood particles or other plant particles. However, this is not intended to solve a wear problem on planetary roller extruders. The aim of this measure is to save time that is required for the melting of the plastic. In this US patent, the entire length of the extruder is required in order to effect drying of the wood or the plant particles in a continuously repetitive build-up of pressure and subsequent relaxation. This causes the excess water / moisture content to evaporate. The water vapor should then be suctioned off. The extraction requires a drop in pressure and the use of an induced draft.
It is intended to repeat the pressure build-up with relaxation until the desired drying is achieved.

The zones of pressure build-up and relaxation can be easily read from the drawing, where areas of high incline alternate with areas of low incline. At the same time, an intensive mixture of wood and plastic should take place. A counter-rotating twin screw extruder is provided for this. Twin screw extruders are characterized by a high pressure build-up and a high mixing effect.
This concept can be PCT / EP2007 / 9140 Do not implement the planetary roller extruder provided. The teeth provided in the planetary roller extruder usually have a constant pitch over the entire length. This is contrary to the concept of changing gradients.

Now the use of planetary roller extruders for the production of mixtures of wood and plastic is known per se. Such considerations can be found, for example, in the following publications: DE 102004005058 . DE 102004005034 . DE 10310510 . DE 10228191 ,
All of these suggestions have in common that they have not become practice-relevant.
This is attributed to the fact that large quantities of wood particles in the mixture are very difficult to penetrate in a planetary roller extruder. This is particularly true when the 60% by weight limit is exceeded, particularly 65% by weight. There is then a risk that the particles will be rolled into the toothing by the orbiting planets and thereby build up on the tooth base. The particles are then no longer displaced by the teeth of the planetary spindles in the tooth base of the central spindle and in the tooth base of the housing teeth. This also applies to particles in the tooth base of the planetary spindle toothing.

The build-up of the particles in the tooth base causes the planets to jump over, which are only held in the toothing of the central spindle and in the toothing of the surrounding housing during their rotation. When skipping, the entire toothing is damaged. The result can be total damage to the gearing with a corresponding breakdown for the repair.
Regardless of the risk of damage caused by the build-up of particles in the tooth base, the plant particles cause considerable wear on the planetary roller extruder.
Now the costs for a planetary roller extruder are much greater than the costs for single-screw extruders and twin-screw extruders.

All systems known in practice use twin screw extruders.
Another example is that in the WO 02/103113 System described for the production of mixtures of wood particles and plastic.

After PCT / EP2007 / 9140 the acquisition costs are reduced by using a planetary roller extruder that supplies several downstream single-screw extruders with the wood particles / plant-plastic mixture. Each of these single screw extruders has the sole purpose of ensuring the pressure necessary for the mixture to pass through the downstream nozzle. With its outlet cross section, the nozzle defines the cross section of the emerging strand. The same or different nozzles can be used. Accordingly, the various single-screw extruders form parallel production lines, which are operated from a common plant section with the mixture described. Instead of the single-screw extruders, other extruders could also be used individually or in groups. However, the single screw extruders are unrivaled in terms of price and fulfill all of the requirements described.
The acquisition costs of the common planetary roller extruder are distributed across all production lines and therefore do not have as strong an impact as when using an independent planetary roller extruder for each production line.

After PCT / EP2007 / 9140 the mixture is used to degas the route. The degassing can take place in the ambient air. The heat contained in the mixture already causes degassing. Degassing can be increased by applying a vacuum.

The degassing at the outlet of the planetary roller extruder can be the only degassing point or can be supplemented with a known degassing at another point of the planetary roller extruder.

Optionally, a storage container is also initially provided behind the planetary roller extruder. The storage container forms a buffer by compensating for production fluctuations between the planetary roller extruder and the downstream production lines. The mixture is kept at the intended temperature in the storage container. Degassing preferably also takes place in the storage container.

The distributor can have various shapes.
A variant is formed by a switch which projects like a knife into the incoming mixture and branches off desired quantities from the stream. The branched quantity can be changed by adjusting the switch. The adjustment of the switch is preferably combined with a quantity measurement, so that a contact for an adjustment of the switch is given when the desired quantity in a branch is undershot or exceeded. This control is preferably provided with a particular inertia, so that not every small gap in the mixture flow leads to an adjustment of the switch. The inertia of the control can be achieved by measuring at intervals. The intervals are at least 5 seconds long, preferably 10 seconds long, more preferably at least 20 seconds long. The inertia of the control can also be achieved in that the adjustment only reacts when larger deviations from the target value are reached. A reaction is preferably provided in the event of a deviation from the target quantity of at least 5% by weight, more preferably with a deviation of at least 10% by weight and most preferably with a deviation of at least 20% by weight.

A switch is sufficient for two branches to two production lines.
With three branches to three production lines, two switches are sufficient.
With four deviations from four production lines, three switches are sufficient.
The number of turnouts is 1 less than the number of branches.

The switches are optionally combined with an open slide. For this purpose, the slide preferably has a flat floor, so that the switches can be moved close to the floor or even in contact with the floor.
The turnouts are articulated and equipped with an adjustment motor.
The quantity is measured either in the area of the filling opening or in the funnel on the downstream single-screw extruders.
The quantity can also be measured by weight measurement on the slide. For this purpose, part of the branch is preferably arranged directly behind the switches and provided there with a measuring device. These can be electrical measuring cells. Such load cells have a strain gauge that reacts to different loads, for example with different resistance for a flowing electrical current.

The interval control can also be combined with the larger quantity deviation described.

The setpoints of the control can preferably be changed in order to take into account an adaptation to different required quantities of mixture in the production lines. The required quantities of mixture in the production lines change, for example, if other profiles of smaller cross-section or larger cross-section are to be produced.

The distributor can also have a distributor cone which directs the mixture emerging from the planetary roller extruder into a channel. Various branches then go from the trough to the downstream production lines. The distributor cone can also direct the mixture directly into the branches. The various branches are then preferably arranged around the distributor cone.
Optionally, the branches are also provided with an adjustable inlet opening and this is combined with a rotatable distributor cone, so that a sufficient quantity of mixture can be guaranteed before each inlet opening by rotating the distributor cone. The amount of mixture is preferably adjusted accordingly. With an intermediate buffer / storage container, the inflowing mixture quantity can be easily adjusted to the requirements via a controllable discharge lock.

This means that the amount of discharge from the buffer / storage container is changed by adjusting the discharge lock if the amount of mixture in front of the inlet openings deviates from a target size.
The adjustability of the inlet openings acts like an adjustment of the switch described above. The same means as for the switch can also be used to adjust the inlet opening.

Optionally, a circumferential scraper is also provided on the distributor cone, which moves the mixture quantity in whole or in part to the various inlet openings. Along the way, the inlet openings are mixed at intervals. Depending on the length and frequency of the intervals, mixture can flow into the inlet opening. As a result, the length and frequency of the intervals can be used as a controlled variable.

Alternatively, a rotating distributor plate is used instead of the distributor cone. The same can be achieved with the distributor plate as with the distributor cone.

Alternatively, a rotary feeder can be used to feed the various branches to the production lines. Each cellular wheel sluice has a cellular wheel. The cellular wheel forms various chambers, which are filled from above and open above the branch to be charged. On the way to the correct branch, other branches that are not to be loaded at the moment can be run over if the filled chamber of the cellular wheel can be closed with a cover. The lid is then opened at the correct junction.
Instead of the cover or in addition to the cover on the cellular wheel, covers or slides can also be provided on the inlet opening of the branches.

The distributor is preferably designed like a pot
This has several advantages. The advantages also include the pot volume. If the pot is large enough, the pot also forms a storage container / buffer.

The various branches in the floor area are connected to the pot. The floor area includes the floor and the lower area of the side walls.

The mixture can be directed in front of the inlet openings by means of guide devices inside the pot. Such a guide device optionally forms a cone. The control device can also be used for other types of distribution.
The same applies to a rotor provided in the pot.
A round pot shape is advantageous for the rotor because the rotatable rotor can then easily move along the container wall.
The rotor preferably includes arms that are straight and / or curved. Even more preferably, the arms are at an angle to the radius of the rotor in each area. If the course is straight, the inclination is always the same. If the course is curved, the angle of inclination changes. The mixture is pressed with the rotor against the inlet openings of the branch.
A semicircular or oval or sickle-like course of the arms is favorable, in which the arms of the rotor open in the direction of rotation, so that the mixture moved by the arms is moved / concentrated on a circular path which runs as close as possible to the center of the inlet openings. Among other things, this has the advantage that there are no dead spaces on the container wall in which the plastic remains for too long and is damaged as a result of excessive heat load.

With regard to the pot, the openings in the pot can also be referred to as outlet openings. The designation outlet opening can even be more appropriate than the designation inlet opening if the branch is not directly connected to the pot, but is arranged at a short distance below the openings in the pot.
Then the above-mentioned devices for changing the opening width are preferably provided below the pot at its openings.
Sliders are optionally used as adjusting devices, the actuation of which partially or even completely closes or opens the openings.
The direction of movement of the slide preferably runs parallel to the bottom of the pot in the radial direction. However, other slide directions can also be considered. The slides can be held in a straight line. The slides can also be arranged so as to be pivotable.
It is advantageous if the slides are provided with a stepping motor that enables a defined movement and position of the slides. The drive for the rotor, however, can be of a simple type.

For operation, maintenance and repair of the distributor, it is advantageous if essential parts of the distributor can be opened. This can be done with movable flaps and removable lids and / or by the fact that essential parts such as the pot can be moved laterally and / or in the radial direction out of the distributor.
This is achieved with suitable rails.

As far as other plants for the production of mixtures of wood and plastic have become known, none of these plants shows a similar technique as that PCT / EP2007 / 9140 ,

The FR-A-2564374 shows the use of an auxiliary extruder next to a main extruder. The auxiliary extruder has the task of feeding recyclate into the main extruder. The specialist knows that recyclate is only permissible in small percentages, based on the amount of fresh plastic in the main extruder. The addition can be metered very well with the auxiliary extruder. This does not teach a separate melting of the plastic for wood-plastic mixtures to solve wear problems in planetary roller extruders.

Also the EP1262294A1 does not give a solution to the wear problems. The publication describes the production of foam from wood-plastic mixtures.

Therefore, it was not obvious from the above publication to use the separate melting of plastic mentioned there to solve the wear problem on planetary roller extruders.

Preferably, the plastic is first mixed with the additives and melted, and the melt mixture is homogenized. This is followed by mixing with the wood particles.
Due to the homogenization, the plastic is evenly distributed over the wood particles. It is favorable for the above process if the melt is thin. Each thermoplastic has a melting point and above the melting point a point at which the plastic becomes gaseous and / or enters into a chemical reaction. The point at which the plastic changes to a gaseous state depends on the ambient pressure. Depending on the nature of the plastic, the melting temperature for polyethylene (PE), for example, can be between 100 and 135 degrees Celsius (PE-LD 105-118 Degree, PE-MD 120-125 Degrees, PE-HD 126-130 Degree, PE-UHMW 10-135 Degrees, PE-LLD 126 degrees). Under appropriate pressure, the melt temperature can be much higher (PE-LD 160-260 Degrees, PE-HD 260-300 Degrees, PE-HD-UHMW 240-300 Degree.
By pressing the wood particles, their voids are at least significantly reduced. The voids / pores in the wood are preferably reduced by at least 10%, preferably by at least 20%, of their initial volume. Optionally, the wood particles are compressed even further, for example reduced to at least 40% of their initial volume. This is done by compressing the wood particles or plant particles. The compaction is provided at least on the surface. The compression on the surface reduces the consumption of plastic that is necessary to establish a sufficient connection between the particles and to reduce the moisture absorption and swelling of the particles to a level that is permissible for the respective application.
Adherence to certain grain sizes has a similar effect.
Chips with a particle size of less than 1 mm, more preferably less than or equal to 0.8 mm, are preferably used. The chips used have a grain spectrum. The main mass of the chips is preferably from 0.3 to 0.4 mm in particle size. The main mass means at least 50%, preferably at least 60% of the chips.

The compression of wood particles for the production of mixtures of wood particles and plastic is in itself the subject of an older proposal. The older proposal provides for the wood particles to be pelletized before being brought together with the plastic. The use of pellets primarily serves to increase the proportion of wood in the mixture, for example to a proportion of more than 80% by weight in the mixture. The pellets make it easier for the wood particles to be drawn into the extruder. The pellets run easily into the feed hopper of an extruder. The pellets are also easy to dose. In practice, however, the pellets have not been tried and tested because there is a risk that the pellets will not disintegrate sufficiently in the extruder, but will disintegrate later if they are moistened after the mixture has been profiled. The danger is much greater when the material is used outdoors if the moistened pellets in the mixture always go through a freeze / thaw change.

During pelleting, the wood particles are also pressed and the cavity in the wood particles is reduced, but this takes place before contact with the plastic melt.
While after the PCT / EP2007 / 9140 Achieving surprisingly good resistance to frost / thaw change and a much lower swelling behavior is achieved, the opposite occurs when using pellets that were produced before contact with the melt.

After PCT / EP2007 / 9140 Processing takes place differently than in the older proposal without the large pellets and their necessary comminution, but by using smaller particles within the above limits, which make comminution unnecessary or become smaller by compression in the extruder. With the pellets there is a risk that the pellets will not be completely crushed again and that uncrushed residues get into the product without plastic getting between the compressed particles. Then moisture absorption of the pellet leads to swelling and loss of particle binding in the pellet residue.

The fusion of plastic melt and wood particles is preferably carried out by preheating the wood particles, so that the flowability of the melt is not significantly reduced by a transfer of heat to the wood particles.

Wood particles and plastic melt are preferably brought together in a planetary roller extruder or in a planetary roller section of an extruder. The planetary rollers consist of a central central spindle, rotating planetary spindles and an internally toothed housing. The planetary spindles mesh simultaneously with the central spindle and the internally toothed housing. The wood particles that get between the teeth of the planetary spindles are particularly intimately mixed with the plastic melt and pressed at the same time.

Traditionally, the wood particles can only be preheated in the extruder. It is advantageous to preheat the wood particles before they are fed into the extruder, because conventional preheating devices only cause a fraction of the cost of an extruder.

The exit temperature of the mixture from the extruder is preferably selected so that the emerging extruded strand has sufficient rigidity, for example, to be able to cool down on a roller conveyor with rollers arranged close to one another, without there being any disadvantageous deformations. However, higher outlet temperatures can also be controlled by calibrating directly behind the extrusion nozzle. The dimensions of its passage opening correspond to the desired cross section of the extrusion strand. However, the contact surfaces of the calibration with the extrusion strand are cooled, so that the extrusion strand solidifies on the outer edge and is therefore resistant to the roller table.
The calibration is very similar to the extrusion die. The extrusion die also has an opening with a cross section that corresponds to the cross section of the desired extrusion strand. The nozzle also preferably has cooling. To the extent that this cooling is sufficient to make the emerging extrusion strand stable on the roller table, calibration in the above sense is unnecessary. In contrast, the use of calibration can be more economical than an extrusion die in special form with a particularly long cooling section.

Advantageously, in particular the extruded profiles, in which the wood particles are immediately mixed with plastic melt after entering the planetary roller section of the extruder and then compressed between the parts of the planetary roller extruder section, have a particularly high strength and a particularly high resistance to moisture absorption and a particularly high level of frost / thaw resistance.

Of the PCT / EP2007 / 9140 individual characteristics are known per se. In the sense is from the EP 1297933A1 the production of mixtures is known, in which plastic is first melted and then mixed and kneaded with wood particles. The mixture is then to be fed to an extruder and pressed into a plate. It is a typical chipboard production. When producing chipboard, it is important to wet the wood particles with the adhesive and then to compress them. Extrusion of the chips does not occur in particle board production. It is typical to mix the chips with the adhesive in a kneader.
After PCT / EP2007 / 9140 on the other hand, an extrusion is provided. No additional kneader is required. Wood particles and plastic are fed directly into the extruder. The wood particle / plastic mixture emerges from the extruder in an “endless” strand.
In addition, not only is more effort to be taken into account in the known method, the kneading of the liquid melt also leads to a higher proportion of plastic.

The EP 1262293A1 also includes a proposal to mix wood chips and plastic. The chips should have a width of 0.5 to 20 mm, a thickness of 0.5 to 2.5 mm and a length of 1 to 50 mm. To wet the wood chips, a jet of liquid plastic is generated and the wood chips are sprinkled into the jet and a layer of material is created on a belt underneath, which is then pressed. An extruder is only provided to liquefy the plastic. This known proposal does not go beyond the known proposal explained above. This also applies insofar as the wetting of fibers with plastic has been addressed in the proposal.

US-PS 5653534 shows a method for reinforcing plastic with fibers. The plastic is brought into a molten form. The fibers are then metered in. The resulting product has essentially the same appearance as plastic without a reinforcement insert. According to PCT / EP2007 / 9140, however, a wood substitute with the appearance of a wooden surface should be created.
In addition, the processing of wood / plastic mixture with a wood content of 60% and more places incomparably higher demands than the processing of fiber / plastic mixture with a fiber content of 30%.

In the PCT / EP2007 / 9140 the mixing of the wood with the liquid melt before pressing / compacting and the temperature of the mixture components are of considerable importance.
A high temperature of the melt is favorable. The higher the melt temperature, the higher the flowability of the melt and the better the melt can penetrate into its cavities / pores before the wood particles are compacted. The maximum melt temperature depends on the material. At the melt temperature, a safety distance from the temperature at which the melt changes into a gaseous state or a chemical reaction occurs is preferably maintained. The safety distance is optionally at least 5%, even more preferably at least 10% and most preferably at least 15% of the temperature at which a transition to the gaseous state or a chemical reaction occurs.

In addition, the melt temperature is limited by the nature of the wood particles. Depending on the nature, the wood particles tend to discolour at higher temperatures.

Depending on the material and pressure, there are different processing temperatures for the melt. Whether the processing area can be fully or partially used depends on the wood particles used and the temperature of the wood particles. At the higher temperatures, highly fluid plastic is created. This means that this plasticization involves strong liquefaction.

Plastic is preferably used, which is recycled at most once. The more often the material is recycled, the worse the flowability becomes with some plastics.
Or plastic is used, which consists of a mixture of fresh material with recycled material and has at least the same flowability as a material that has not been recycled more than once.
Fresh plastic, non-recycled material, is even more preferred.
Optionally, the plastic is plasticized together with aggregates or the aggregates are mixed with the plastic after the plasticization before the mixture with the wood particles takes place. These additives preferably include dyes and adhesion promoters and water repellents.

The wood particles are preferably used in the form of chips, for example in the form of sawdust. Sawdust is produced in large quantities when processing wood. At the same time, the dimensions of sawdust are within certain limits. Sawdust is usually conveyed with compressed air. With the compressed air, the wood particles can be transported within wide limits to any place, for example in the feed hopper. Compressed air is usually generated using fans that draw air in on one side and force the air into a transport line on the other side. At the destination of the wood particle transport, the compressed air must be separated from the wood particles again. This is done using suitable filters. In practice, however, the filters cannot separate every dust particle from the compressed air. Particulate matter enters the environment to a greater or lesser extent. After PCT / EP2007 / 9140 the particulate matter emissions should be reduced. Therefore suction air is preferably used to transport the wood particles. At the destination of the suction air transport, the wood particles are separated from the suction air with filters, as in the case of compressed air transport.

The plasticization of the plastic can take place in various facilities. Batch liquefaction is conceivable. A heated pressure vessel is preferably provided for the liquefaction of the plastic. Batch operation allows only one intermittent liquefaction process when using a single pressure vessel with a single chamber. With two tanks, however, a continuous liquefaction process can already be carried out. The same applies to a single container with two melt chambers, which can be alternately filled and emptied. The containers are preferably emptied by a pump. The pump not only ensures rapid emptying. The pump can also build up a high pressure in the melt.

The melt is preferably plasticized in an extruder. The melt temperature can easily be controlled in the extruder.

The wood particles can be heated in one or more stages. The heating takes place before contact with the plastic. Depending on the temperature of the supplied melt and the further processing of the mixture and the associated temperature control, the wood can experience further heating or cooling due to the supplied melt and further processing.
The preheating of the wood particles is preferably at least 50 degrees Celsius, even more preferably at least 100 degrees Celsius and most preferably at least 150 degrees Celsisus.

The multi-stage preheating of the wood particles is optionally carried out with different heating devices. Each of the heating systems can work continuously or discontinuously. A continuously operating heating system is, for example, a heating tape and / or a tunnel oven.

The heating tape is a heated belt conveyor on which the wood particles heat up. The wood particles can also be passed through the heating tape using suitable heat radiators. It is beneficial to enclose the heating tape in order to avoid a loss of temperature. A tunnel oven differs from the heating belt in that it is not the conveyor belt but the housing that is provided with a heating device and / or that a heating gas is passed through the housing. The heating temperature is selected so that any risk of ignition / fire for the wood is avoided.

Discontinuous heating can take place in a container until the wood particles have reached the desired temperature. A gaseous heating medium flows through the container. Inert heating gases are cheap. Inert heating gases can be introduced into the container at a much higher temperature than air, for example, without the risk of fire.
After the desired heating of the wood particles, the container can be opened and the wood particles can be removed from the container for mixing with the plastic.

If all or part of the preheating takes place in an extruder or an extruder section (module), the mixing of plastic and wood particles preferably takes place in a downstream further extruder or downstream extruder section. Each extruder / extruder section is provided with a material feed opening and with an outlet for the processed material. The material feed opening is at one end of the extruder. From there, the material is conveyed under the desired treatment to the material outlet at the other end of the extruder.

After PCT / EP2007 / 9140 the plastic melt is preferably fed into the extruder via an intermediate ring in which the wood particles are guided. The intermediate ring is arranged at the joint between extruder modules.
Valves or orifices for adjusting the melt flow are optionally provided in the various feed lines to the intermediate ring. The valves optionally allow readjustment and influence on the melt flow during operation. This can be used to even out or create differences. In addition to or instead of the valves, a change in the melt flow can also be achieved by means of inserts which are positioned in the feed lines. The inserts can also be provided in the intermediate ring.

Incidentally, the melt feed is determined by the speed of the extruder intended for plasticizing the plastic or. determined by the pressure of the melt. The melt pressure can be measured and changed by changing the extruder speed.

Optionally, the liquid melt is fed into the single-screw module / section at the end of the heating section. If necessary, the extruder provided for the production of the liquid plastic melt is directly connected to the single-screw module / section provided for heating the wood particles. Or a feed line is provided which leads to the housing of the single-screw module / section.

The extruder flanged directly to the single-screw module and used to produce liquid plastic melt can be referred to as a side arm extruder. With regard to the side arm extruder, the extruder, in which the mixture of wood particles and liquid plastic melt takes place, is the main extruder. As explained above, a contemporary main extruder is composed of several modules.
This side arm extruder can have the same design as a single screw module of the main extruder. However, another type of extruder can also be used as the side arm extruder, for example a twin-screw extruder or a planetary roller extruder.

For the introduction of the liquid plastic melt into a single-screw module / section of the main extruder, its housing must be drilled. The casing jacket, which is double-walled for temperature control (for guiding a temperature control agent, depending on the temperature, for example water), is drilled through. So that the plastic melt does not flow into the hollow jacket on the one hand and the tempering agent does not contaminate the melt on the other hand, a flange can be attached which projects into the bore with a collar and closes the hollow jacket again.

The liquid melt can also be introduced into the adjacent planetary roller module or into an intermediate piece between the planetary roller module and the single-screw module. Likewise, the melt can be introduced into intermediate pieces between the planetary roller module and a module of another design.

• die Bohrung durch das Gehäuse hindurchgeführt ist und in die im Gehäuse sitzende Buchse ragt,
• wobei die Materialzuführung mit einem Zufuhrungsgehäuse in die Bohrung ragt und
  • aa) wobei die Bohrung im Bereich der zum Temperieren dienenden Kanäle eine ringförmige Erweiterung aufweist, so dass um das Zuführungsgehäuse herum ein ringförmiger Verbindungskanal für die zum Temperieren dienenden Kanäle entsteht oder
  • bb) wobei die Bohrung bis in eine Nut reicht, die sich über den gesamten Umfang oder über einen Teil des Umfangs der im Gehäuse sitzenden Buchse erstreckt und deren Breite größer als der Durchmesser des Zuführungsgehäuses ist, so dass um das Zuführungsgehäuse herum ein Verbindungskanal für die dem Temperieren dienenden Kanäle entsteht oder
  • cc) wobei ein Zuführungsgehäuse verwendet wird, das in die Buchse ragt, wobei das Zuführungsgehäuse im Bereich der dem Temperieren dienenden Kanäle mit mindestens einem Verbindungskanal für diese Kanäle versehen ist Vorteilhafterweise kann der Verbindungskanal nach cc) spanabhebend durch Fräsen oder Drehen außen in die das Zuführungsgehäuse eingearbeitet werden.Vorzugsweise ist ein Zuführungsgehäuse mit mehreren Verbindungskanälen vorgesehen, so dass jede durch die Bohrung entstandene Unterbrechung eines Kanals durch einen Verbindungskanal aufgehoben bzw. überbrückt worden ist.
• Noch weiter bevorzugt ist ein Zuführungsgehäuse mit mehreren Verbindungskanälen, die übereinander liegen. Die einzelnen Verbindungskanäle können als neben einander liegende Nuten in das Zuführungsgehäuse gearbeitet werden. Die Kanäle können außen an dem Zuführungsgehäuse liegen.
• Günstig ist dabei, wenn die übereinander liegenden Verbindungskanäle eine Höhe besitzen, die geringer als die Breite ist. Zugleich ist die Breite so groß gewählt, dass die Verbindungskanäle gleichwohl einen ausreichenden Querschnitt zur störungsfreien Weiterleitung des Temperierungsmittels besitzt, vorzugsweise ist der Querschnitt gleich.
• Günstig ist, wenn die Höhe der Verbindungskanäle so gewählt ist, dass die Gesamthöhe der übereinander liegenden und durch einen Steg voneinander getrennten Verbindungskanäle nicht höher als die Höhe bzw. Tiefe der zum Temperieren dienenden Kanäle in der Buchse ist.
• Vorteilhafterweise können die übereinander liegenden Kanäle mit das Zuführungsgehäuse in diesem Bereich außen umschließenden Rohrmantel geschlossen werden. Der außen liegende Rohrmantel ist dann mit Einlaßöffnungen und Auslaßöffnungen versehen. Jede Einlaßöffnung ist so angeordnet, dass sie an dem zugehörigen, durch die beschriebene Unterbrechung entstandenen Kanalende liegt
• Wahlweise sind die Verbindungskanäle auch an einer Innenseite des Zuführungsgehäuses eingearbeitet worden und sind die Verbindungskanäle durch einen innen liegenden Rohrmantel verschlossen. Durch außen in das Zuführungsgehäuse eingearbeitete Einlaßöffnungen und Auslaßöffnungen entstehen gleichwohl Verbindungskanäle. oder
  • dd) wobei die Bohrung gegenüber dem Zuführungsgehäuse vergrößert ist und wobei in dem Gehäuse ein Einsatz mit einer Öffnung oder einem Anschluß zur Aufnahme des Zuführungsgehäuses vorgesehen ist. Der Einsatz besitzt außen liegend oder innen liegend einen oder mehrere Verbindungskanäle, die wie die Verbindungskanäle unter cc) ausgebildet sind bzw. hergestellt werden.
  • ee) wobei in der Bohrung ein Einsatz sitzt, an dem das Zuführungsgehäuse befestigt ist und der Einsatz außen liegend oder innen liegend oder innen liegend einen oder mehrere Verbindungskanäle besitzt, die wie die Verbindungskanäle unter cc) ausgebildet sind bzw. hergestellt werden.

To insert the liquid melt into the planetary roller module of the main extruder, its housing can be drilled. The planetary roller module is usually tempered. For this purpose, it has a housing with a double jacket that is opened through the hole and must be closed again.
After DE 10356423 is achieved with a jack that

• the bore is passed through the housing and protrudes into the socket seated in the housing,
• the material feed with a feed housing protrudes into the bore and
  • aa) wherein the bore has an annular extension in the region of the channels used for temperature control, so that an annular connecting channel for the temperature control channels is created around the feed housing or
  • bb) wherein the bore extends into a groove which extends over the entire circumference or over a part of the circumference of the bushing seated in the housing and whose width is larger than the diameter of the feed housing, so that a connecting channel for the feed housing channels used for tempering arise or
  • cc) where a feed housing is used which protrudes into the socket, the feed housing being provided with at least one connecting channel for these channels in the region of the tempering channels. Advantageously, the connecting channel according to cc) can be machined by milling or turning the outside into the feed housing A feed housing with a plurality of connecting channels is preferably provided, so that each interruption of a channel caused by the bore has been canceled or bridged by a connecting channel.
• A feeder housing with a plurality of connecting channels which are located one above the other is even more preferred. The individual connecting channels can be worked into the feed housing as adjacent grooves. The channels can lie on the outside of the feed housing.
• It is advantageous if the connection channels lying one above the other have a height that is less than the width. At the same time, the width is chosen so large that the connecting channels nevertheless have a sufficient cross-section for the trouble-free forwarding of the temperature control means; the cross-section is preferably the same.
• It is favorable if the height of the connecting channels is selected such that the total height of the connecting channels lying one above the other and separated from one another by a web is not higher than the height or depth of the channels in the socket used for temperature control.
• Advantageously, the ducts lying one above the other can be closed with a tubular casing which surrounds the feed housing in this area on the outside. The outer tubular jacket is then provided with inlet openings and outlet openings. Each inlet opening is arranged so that it lies on the associated channel end resulting from the interruption described
• Optionally, the connection channels have also been incorporated on the inside of the feed housing and the connection channels are closed by an inner tubular jacket. Connection channels are nevertheless formed by inlet openings and outlet openings worked into the outside of the feed housing. or
  • dd) wherein the bore is enlarged relative to the feed housing and an insert with an opening or a connection for receiving the feed housing is provided in the housing. The insert has one or more connection channels on the outside or on the inside, which, like the connection channels under cc), are designed or manufactured.
  • ee) wherein an insert is seated in the bore, to which the feed housing is fastened and the insert has one or more connecting channels on the outside or inside or on the inside, which are designed or manufactured like the connecting channels under cc).

The feed housing described above can penetrate the bushing located in the extruder housing to such an extent that it completely or partially closes with the inner surface of the bushing. The feed housing is preferably adapted to the inner surface of the bushing and can be completely flush with the inner surface of the bushing. This can also be applied to internally toothed bushings in an extruder barrel. The adaptation can be achieved by turning or milling or grinding or when adapting to internally toothed housing bushings in that a toothing is worked into the housing wall in the same way as for the internal toothing of those located in the extruder housing Rifle. The use of spark erosion for gear cutting is favorable.

For the rest, the same applies to the connection of the part used for the production of liquid plastic melt to the housing of the planetary roller module as to the connection to the single-screw module.

If the side arm extruder is connected to an intermediate piece, it can be a cooled or uncooled intermediate piece.
Each intermediate piece preferably consists of a tubular or annular part, to which the side arm extruder is flanged, and two flanges, with which the intermediate piece is held on the adjacent modules of the main extruder.
In the case of a cooled intermediate piece, the intermediate piece has a double jacket on the tubular or annular part, which can be penetrated, for example, in the form described above. In the case of an uncooled intermediate piece, there is no need for a double jacket with the measures which then result in the case of penetration to ensure the passage of temperature control agents.

The side arm extruder explained can have different designs.
There are single screw extruders, twin screw extruders and planetary roller extruders.
The single-screw extruder is the cheapest type of extruder, but also the smallest type of extruder.
When using a single screw extruder, the pitch of the screw should cause the desired conveying effect.

The twin-screw extruder has two parallel and intermeshing screws. The twin screw extruder is more complex than a single screw extruder. However, the twin-screw extruder has a much greater conveying effect than a single-screw extruder. Nevertheless, the twin screw extruder is still relatively cheap. In addition, the twin-screw extruder is still very small.

Due to the high conveying effect, the twin screw extruder makes it easy to ensure that the liquid melt is injected into the planetary roller module at the correct pressure.

A planetary roller part is optionally used for this side arm extruder. In use, this planetary roller part can also be operated in such a way that the pressure required to inject the liquid melt is created.

The invention ties in with the PCT / EP2007 / 9140 on. The procedure has proven itself. In the meantime, there are many hundreds of tons of wood particles / plastic mixtures after the PCT / EP2007 / 9140 manufactured and distributed.

Nevertheless, the invention has set itself the task of improving the method. The invention is used in the consideration of increasing the economy by reducing wear.

According to the invention this is achieved with the features of the main claim.
The subclaims describe advantageous exemplary embodiments.

According to the invention, the principle of melting plastic, separate from the wood particles, is adhered to. Different from after PCT / EP2007 / 9140 However, the wood particles are not fed into the planetary roller module of the main extruder via a single-screw extruder, but rather are fed into the planetary roller module via a side-arm extruder designed as a twin-screw extruder. The wood particles are fed directly onto the planetary spindles rotating in the planetary roller module.
At the same time, according to the invention, at least part of the plastic melt is placed in the planetary roller module before the wood particles are introduced. The melt wets all the contact surfaces of the extruder with the wood particles before the wood particles come into contact with these extruder surfaces. There the melt lowers the friction values of the contact surfaces in the extruder.
The proportion of the melt introduced before the wood particles are introduced into the planetary roller module is at least 5% by weight of the total envisaged amount of melt, preferably at least 15% by weight of the total envisaged amount of melt, even more preferably at least 30% by weight of the total envisaged amount of melt and most preferably at least 45% by weight. of the total envisaged amount of melt. The proportion of the melt amount can also be 60% by weight or 75% by weight or 90% by weight or even 100% by weight of the envisaged amount of melt.

If the entire amount of melt is fed into the extruder before the wood particles are added, only one melt feed to the extruder is provided, which has been arranged in the direction of conveyance of the extruder before the wood is added to the extruder housing.
Insofar as the melt addition is split before the addition of wood and after the addition of wood, the corresponding melt feed lines to both addition points are necessary.
When using an extruder, as in the PCT / EP2007 / 9140 , The extruder for the melt addition can be provided at the point at which the main part of the envisaged quantity of melt is added. The second addition point is then fed via a melt line which leads from the extruder to the second addition point.

When using one from the PCT / EP2007 / 9140 Known melt container and a pump for the addition of the melt, only a single melt line from the pump to the one addition point is provided if the entire amount of melt is to take place before the wood is added.
When the melt is distributed over two addition points, two melt lines are preferably provided from the pump to the two addition points, one for each addition point. A valve or another device for adjusting the melt flow is preferably provided in at least one melt line. A device for adjusting the melt flow is preferably provided in each of the melt lines.

The melt addition before the wood particle addition by means of a side entry can be done as after PCT / EP2007 / 9140 respectively. For the purposes of the invention, a melt entry from above or from below is also a side entry. A side arm extruder in the form of a twin-screw extruder is used. In the construction after the PCT / EP2007 / 9140 the two screws of the side arm extruder lie with their central axes on a line parallel to the longitudinal axis of the planetary roller extruder. In addition, the melt can also be introduced vertically from above or inclined from above or from below or inclined from below, because the melt produced with the side arm extruder can be fed in at any peripheral point of the extruder. The same applies to a melt feed from a melt container with a pump.

• -der Planetwalzenmodul nimmt mehr Holzpartikel in der Zeiteinheit auf als bei der Anordnung des Doppelschneckenextruders, die aus der PCT/EP2007/9140 bekannt ist. Die Einfüllmenge an Holzpartikeln pro Zeiteinheit kann auch durch Erhöhung der Drehzahl des Seitenarmextruders gesteigert werden.
• -die Pulsation bei der Zuführung und Verarbeitung des Holzes wird erheblich reduziert. Die Pulsation bei der Zuführung und Verarbeitung des Holzes/Holzpartikel entsteht auch bei gravimetrischer Dosierung durch Schwankungen in der Korngröße und/oder in der Art des Holzes/Holzpartikel und/oder in einer Vorverdichtung. Auch andere Eigenschaftsänderungen können trotz gravimetrischer

• Dosierung eine Pulsierung verursachen. Aus den gleichen Gründen und ähnlichen Gründen kann es trotz volumetrischer Dosierung zu einem Pulsieren in der Holzzuführung geben. Extrem macht sich die Pulsation bei Einschneckenmodulen zum Eintrag der Holzpartikel bemerkbar. Schon geringste Unterschiede des Einsatzgutes bewirken bei Einschnecken Schwankungen in dem Materialdurchsatz durch den Extruder.

Bei der Einführung der Holzpartikel in einen Planetwalzenmodul kommt noch hinzu, daß die umlaufenden Planetspindeln in den eintretenden Partikelstrom dringen. Dabei wird ein Teil der Partikel in den Partikelstrom zurückgedrängt. Das kann die Pulsation verstärken.
Durch das Drehen/Verschwenken des Doppelschneckenextruders reduziert sich überraschenderweise die Pulsation.
Beste Ergebnisse lassen sich mit einer Drehung/Schwenkung um 90 Grad erreichen, so dass die beiden Mittelachsen dieses Seitenarmextruders genau senkrecht zur Mittelachse des Hauptextruders verlaufen. Senkrecht zu der Mittelachse des Hauptextruders kann „vertikal“ sein, wenn die Mittelachse horizontal verläuft. Da der Bezeichnung Seitenarmextruder nach der vorliegenden Erfindung auch alle Ausführungen umfasst, bei denen die Mittelachse des Seitenarmextruders in einer Ebene steht, die quer, vorzugsweise senkrecht, zu der Mittelachse des Hauptextruders steht. Dabei kann die Mittelachse des Seitenarmextruders bei horizontaler Anordnung der Mittelachse des Hauptextruders jede Lage von horizontal bis senkrecht einnehmen. Bei geneigter Lage der Mittelachse des Hauptextruders können die Mittelachsen des Doppelschneckenextruders jede Lage in der Ebene einnehmen, die quer, vorzugsweise senkrecht, zu der Mittelachse des Hauptextruders verläuft.Depending on the nature of the feed materials and the operating conditions, it can be advantageous to increase the entry of wood particles. In the case of a side arm extruder designed as a twin-screw extruder for the wood feed, it is advantageous to rotate / pivot this side arm extruder. Surprisingly, the wood particle entry is improved in two ways:

• -The planetary roller module absorbs more wood particles in the time unit than with the arrangement of the twin-screw extruder, which results from the PCT / EP2007 / 9140 is known. The filling quantity of wood particles per unit of time can also be increased by increasing the speed of the side arm extruder.
• -The pulsation during the feeding and processing of the wood is significantly reduced. The pulsation in the feeding and processing of the wood / wood particles also occurs with gravimetric dosing due to fluctuations in the grain size and / or in the type of wood / wood particles and / or in a pre-compression. Other property changes can be done despite gravimetric

• Dosage cause a pulsation. For the same reasons and similar reasons, there may be a pulsation in the wood feed in spite of volumetric dosing. The pulsation is extremely noticeable in single-screw modules for the entry of the wood particles. Even the slightest differences in the feed material cause fluctuations in the material throughput through the extruder for single screws.

In addition, when the wood particles are introduced into a planetary roller module, the rotating planetary spindles penetrate the incoming particle stream. Some of the particles are pushed back into the particle stream. This can increase the pulsation.
By rotating / swiveling the twin-screw extruder, the pulsation is surprisingly reduced.
The best results can be achieved with a rotation / swivel of 90 degrees, so that the two central axes of this side arm extruder run exactly perpendicular to the central axis of the main extruder. Vertical to the central axis of the main extruder can be "vertical" if the central axis is horizontal. Since the term side arm extruder according to the present invention also includes all versions in which the central axis of the side arm extruder is in a plane which is transverse, preferably perpendicular, to the central axis of the main extruder. The central axis of the side arm extruder can assume any position from horizontal to vertical when the central axis of the main extruder is arranged horizontally. When the central axis of the main extruder is inclined, the central axes of the twin-screw extruder can assume any position in the plane that runs transversely, preferably perpendicularly, to the central axis of the main extruder.

The invention takes over from the older proposal of PCT / EP2007 / 9140 the entry of the separately melted melt by means of a side arm extruder or by pump from a melt container.
One of the in the PCT / EP2007 / 9140 preferred arrangements of the side arm extruder for the melt feed has a small distance from the drive end of the planetary roller module. The same goes for for the entry of processed melt with a pump.
The distance according to the invention of the entry of the wood particles by means of a side arm extruder takes place at a small but still sufficient distance from the side arm extruder for the melt entry. The distance is chosen so that it is sufficient for the desired wetting of the intermeshing extruder parts. The distance is measured in the axial direction between the incoming wood particle flow and the incoming melt flow.
For the wood particle flow, the opening width of the entry opening in the jacket of the main extruder is decisive for the particle flow. The distance measurement can take place from the point of the entry opening which comes closest to the melt entry in the axial direction.
Different situations can arise for the melt flow depending on the nozzle or nozzles with which the melt is injected into the main extruder. If the melt entry, like the wood particle entry, takes place via a single entry opening in the jacket of the main extruder, the same applies to the melt flow as to the wood particle flow.
It would be conceivable that instead of one entry opening, several smaller entry openings are arranged distributed over a circle of the circumference of the jacket. Then melt enters the main extruder from all sides of the jacket circumference.
With the planetary roller extruders, a ring construction for the injection of melt has prevailed. There is a circumferential melt channel in the ring construction, to which various nozzle openings lead. The other end of the associated nozzles opens in the axial direction of the main extruder towards the extruder outlet / extruder discharge. In this case, the distance from the entry opening for the wood particles to the plane in which the nozzle exit openings of the ring construction lie is measured.

If a side arm extruder is used for the entry of the wood particles and a pump for the melt entry, the melt entry via the pump can be carried out in the same way in the same way via one or more jacket openings on the main extruder or via a ring construction in the main extruder. Accordingly, the distance measurement

Using two side arm extruders (one for the wood particle entry, the other for the melt entry) results in a concise planetary roller module with the two side arm extruders. As with other main extruders, this planetary roller module and other extruder modules of the main extruder have a common central spindle. A distance of at most 1D is usually required for adequate wetting of the toothed extruder parts. A smaller distance of 0.5D or even less distance may be sufficient. D is the pitch circle diameter for the internal teeth of the planetary roller module.
When using two side arm extruders (one for the wood particle entry, the other for the melt entry), it is advantageous for the accessibility of the side arm extruders if the side arm extruders are diametrically opposed to each other on the planetary roller module of the main extruder.

Optionally, several sections are provided instead of the one planetary roller module, at least one side arm extruder, preferably both side arm extruders, being connected to an intermediate piece. The intermediate pieces then form, together with one or more remnants in planetary roller extruder construction, a component of the same length and with the same connecting dimensions as the planetary roller module described above with the two side arm extruders. This also applies to the common central spindle and the planetary spindles.
At least the remaining pieces mentioned have housings with the same internal toothing as the one-piece planetary roller module with the two side arm extruders. Preferably, the two intermediate pieces with the connected side arm extruders also have the same internal toothing and there is a continuous opening through the planetary roller module composed of intermediate pieces and remaining pieces. This continuous opening not only gives space for the central spindle, but also space for planetary spindles which, like the planetary spindles of the one-piece planetary roller module with the two connected side arm extruders, extend through the entire, assembled module. The planetary spindles slide on a thrust ring at the exit end of the assembled module. No further thrust rings are provided in the assembled module.

As explained above, each intermediate piece consists of a tubular housing with a fastening flange at each end. The housing is preferably cooled. The side arm extruder or the pump is flanged to the tubular housing of the intermediate piece.

For the wetting of the toothed extruder parts according to the invention before the addition of wood particles with liquid plastic melt, conventional rings can be used which are provided on the inside with a melt line / channel which lead to outlet openings on the end face of the rings which face the extruder parts to be wetted.
New rings are preferably used, in which the internal melt line / channel is on the same end face as the conventional rings opens, but the opening is formed by an arcuate gap which extends at least over 300 degrees, preferably over at least 330 degrees and even more preferably over at least 345 degrees on the end face of the ring. The arcuate duct / fuse line has two ends. An annular channel / melt line in the ring can also be considered, in which the melt can be distributed in an uncontrolled manner. The distribution of the melt is better in the curved duct / fusible duct.

By closing the channel at one point, an arcuate channel / melt line can be made from an annular channel / melt line.
In the case of an arcuate channel / melt line, the melt is preferably fed in at half the floor length, so that the melt can extend from this point to the same extent in each circumferential direction of the ring.

For the sewer / melt line, the ring can optionally be composed of several parts, so that the manufacture and maintenance of the ring is simplified. For example, the ring can form an open channel, in particular a U-shaped cross section, the open end of which is closed by a second part in the form of an annular cover. A U-shaped cross-section is created, for example, by a groove in the ring. Such rings with lids are known per se, in which there are openings for degassing the melt or for introducing liquid additives. What is new is to design the cover for the supply of melt in such a way that it leaves a gap at one edge of the U-shaped recess / groove of the channel / melt line in the operating position / closed position.

Optionally, the ring according to the invention can also be combined with other rings in one construction. Such a ring can be, for example, the thrust ring.

In the case of the combination of different rings, it is advantageous if both rings complement each other. When applied to the ring construction according to the invention, this can mean that the thrust ring also forms the cover for the ring according to the invention.
The ring according to the invention can also be combined with other extruder parts.
A combination with the internally toothed housing socket can also be used. The housing bushing can form the cover for the ring according to the invention.

A combination of several functional parts of the extruder with the ring according to the invention is also optionally provided.

For example, a nozzle can be formed with a U-shaped groove in the end face of the ring according to the invention. The groove in the end face of the ring according to the invention pointing in the working / conveying direction results in an outer web which forms the outer, annular part of the end face and an inner web which forms the inner, annular part of the end face. The outside web is many times thicker than the inside web.
In the application of the ring according to the invention to planetary roller extruders, the groove becomes a channel / melt line in that the ring with the outer web and its outer end face is pressed sealingly against the internally toothed bush in the extruder housing.

The inner web ends at a short distance from the end face of the internally toothed bushing of the extruder housing. This forms the opening gap, from which melt melts out during operation and wets the toothed extruder parts.

The gap width depends on the amount of melt that is to flow through the gap per unit of time.
This amount of melt results from the current extruder output and the intended plastic content for the addition into the extruder before the addition of wood.
The temperature and pressure of the melt are adjusted / increased / reduced for the necessary throughput of this melt through the gap. This is done by measuring this amount of melt until the desired amount of melt is reached. An average gap width of at least 0.2 mm, more preferably of at least 0.4 mm and most preferably of at least 0.6 mm is preferably provided.

The gap on the ring according to the invention is preferably chosen narrowly in the area of the melt entry into the channel / melt line and widens (gap width increases) - starting from the entry point into the channel / melt line - with increasing distance from the entry point. This is to take into account the pressure drop in the melt that arises from the beginning of the gap to the end of the gap, so that the melt emerges from the gap and the toothed extruder parts are wetted more evenly. The expansion is smaller for planetary roller extruders with a small size than for planetary roller extruders with a large size. For a 150 mm extruder (the size designation corresponds to the pitch circle diameter of the internal toothing of the housing or the internally toothed housing bush), the expansion is preferably at least 0.3 mm, even more preferably at least 0.6 mm and most preferably at least 0.9 mm.

The ring according to the invention is preferably tempered, so that it is ensured that the melt in the ring does not cool excessively and is also not excessively heated. The danger of excessive heating arises when the wood / plastic mixture is processed in the extruder. Energy is introduced into the mixture, which has to be removed again.
The risk of excessive cooling arises in particular when the material flow is interrupted, when the extruder is shut down, and when the extruder is started up.

For the cooling of the ring, a cooling channel is provided in the ring, through which tempering agent is passed in the operating case. In the exemplary embodiment, the temperature control agent is water, for processing wood particles with polyethylene.

After PCT / EP2007 / 9140 the wood can be preheated in the extruder alone and / or fed into the extruder already preheated.
The task in the extruder can be according to the PCT / EP2007 / 9140 via a funnel and a stuffing screw.
According to the invention, it is optionally provided that the wood particles are first fed into a side arm extruder, preheated therein and then fed into the planetary roller extruder for mixing with the melt. A twin-screw extruder is preferably provided as the side arm extruder.

In addition, the invention has recognized that the type of planet spindles used in the planetary roller module with both side arm extruders can be important for the mixing of wood particles with liquid plastic melt. In addition to the type of planet spindles, the number of planet spindles can be selected within wide limits. In addition, different types of planetary spindles can be combined.

The main types of the known planetary spindles are standard spindles, hedgehog spindles, knob spindles and transport spindles (TT spindles).
Standard spindles have continuous and unidirectional helical teeth. In a cross section of the normal spindle, one tooth is provided next to the other on the pitch circle of the toothing. The number of teeth is a full number. The shape of the tooth is determined by the type of toothing and the tooth module. Hedgehog spindles are made from standard spindles by rotating annular recesses in the standard spindles at intervals. The resulting reduced number of teeth reduces the conveying effect of the planetary spindles.
Knob spindles are also made from standard spindles. This is done by counter-cutting the normal spindles. The additional, opposite toothing cuts the teeth of the normal toothing at an angle, which is preferably 90 degrees, so that nubs are formed. This interlocking has a minimal conveying effect, but a maximum mixing effect.

The transport spindles are also made from standard spindles. One or more teeth are worked out from the teeth lying on the pitch circle. At least one tooth, preferably at least three teeth, should remain. The transport spindles are characterized by a high transport effect / conveying effect in the conveying direction.
In the entry of wood particles and plastic melt according to the invention, preferably at least 50% of the planetary spindles are designed as transport spindles, more preferably at least 75% of the planetary spindles are designed as transport spindles and most preferably all planetary spindles are designed as transport spindles.
If not all planetary spindles are designed as transport spindles, it is advantageous to use normal spindles as the remaining spindles.

Various known systems are shown in the drawing, the technology of which the invention is based. The show 1 to 11 the well-known plants and the 12 to 15 the further development according to the invention.

1 shows an extruder for the production of mixtures of plastic and wood particles. The extruder has four sections. Three extruder sections are designed as planetary roller extruder sections, the fourth extruder section is designed as a single-screw extruder and is used for material feed.
The housing of the planetary roller extruder sections and the housing of the single-screw extruder section are designated by 5. Any housing 5 has welded flanges 6 and 7 which are screwed together in a form not shown. The housing 1 is with flanges 3 and 4 provided that like the flanges 6 and 7 serve the attachment. Any housing 1 and 5 is lined with bushings on the inside.
Furthermore, channels are shown on the inside of the housing, which are acted upon with heating medium or coolant as required.

The illustrated ends of the housing 5 are turned out at the back and each with a centering ring, thrust ring and wear ring 8th Mistake.
The thrust ring and wear ring 8th forms the sliding surface for planetary spindles 10 , The thrust ring and wear ring 8th has an inside diameter of is smaller than the outer diameter of the movement path on which the planetary spindles rotate around the central spindle.

All extruder sections have a common spindle. This common spindle is designated 9 in the area of the planetary roller extruder sections and 19 in the area of the single-screw extruder section serving as a feed.
In the exemplary embodiment, the feed material is formed by wood chips. The wood chips are fed through a funnel through an opening 2 metered. The wood chips are drawn off from a silo in a manner not shown by means of suction air conveyors and passed into a filter arranged above the funnel and separated from the suction air. The wood chips are drawn from the filter into the funnel by means of a stuffing screw, not shown. A volume metric measurement of the amount of sawdust takes place in the funnel. In other exemplary embodiments, an additional gravimetric measurement or only a gravimetric measurement is provided. The suction air conveyor is controlled based on the measurement results.

The first extruder section forms a feed for the second extruder section. In the second extruder section, metering and mixing with liquid plastic melt and compression take place; homogenization of the mixture in the third extruder section. The mixture is cooled to the exit temperature in the last extruder section. In the exemplary embodiment, the wood has a share of 70 % By weight and the plastic a share of 30 % By weight of the mixture. In other exemplary embodiments, the proportion of wood in the mixture is, for example, 65% or 75%. Surcharges such as flame retardants (for construction products), paint and water repellents have been added to the plastic content. In the exemplary embodiment, the flame retardant is aluminum hydroxide (ATH) in a proportion of 16% by weight, based on the mixture as a whole. In other exemplary embodiments, a different flame retardant or a mixture with other flame retardants is provided. Overall, flame retardant levels can 10 up to 20% by weight. The proportion of colors in the exemplary embodiment is 4% by weight, based on the entire mixture. In other embodiments, the proportion of colors 1 up to 5% by weight.
In the exemplary embodiment, the aggregates are first mixed into the melt and introduced with the melt into the extruder for mixing with the wood.

The resulting mixture occurs at the extruder tip 12 into an extrusion nozzle, not shown, the opening of which is modeled on the cross section of a floor board, so that an extruded strand with the cross section of a floor board is produced by extruding the mixture. Cutting the extrusion strand to length, not shown, creates floorboards with the appearance of a wooden floorboard.

The floorboards are profiled on the underside. The profiles are selected so that there is a wall thickness of 10mm. In other exemplary embodiments, 8 to 12 mm wall thickness is selected.
The profiling includes a cavity or chamber formation.

In 2 is for introducing the liquid melt on the planetary roller part 5 a side arm extruder 20 intended.
The side arm extruder is designed as a twin-screw extruder. The twin screw extruder consists of two counter-rotating screws. In the side arm extruder 20 Plastic granules, in the exemplary embodiment polyethylene (PE) granules, are filled in, not shown, compressed and heated and formed on the way to a liquid melt. With the PE granulate, additives such as paint and water repellant have been applied at the same time. The aggregates find an advantageous distribution in the melt.

With the twin screw extruder, the liquid melt can enter the planetary roller section with considerable pressure 5 be injected. The liquid melt wets the wood particles on the surface and penetrates into the cavities / pores. During the subsequent densification of the wood particles, the voids / pores are reduced and closed by the melt, which remained open when the melt was injected. The melt is applied at a temperature at which the melt remains liquid even if it has given off heat through contact with the wood particles.

The melt acts like an adhesive between the different wood particles.

The side arm extruder housing 20 is in several parts. The headboard 21 sits as a feed housing in a hole in the housing of the planetary roller part 5 , The hole also penetrates the associated socket 22 and closes with the inner surface of the socket 22 from.

In the exemplary embodiment, the side arm extruder is suitable for generating very high entry pressures.

In the embodiment of the 1 will the in 4 planetary roller part shown 5 used immediately after the material feed or immediately after the filler. In another embodiment, the planetary roller part comes 5 with the Side arm extruder after the second planetary roller part to be used as the third planetary roller part.
In further exemplary embodiments, each planetary roller part can be provided with a side arm extruder for introducing liquid melt.

In a further embodiment according to 3 the extruder housing of the side arm extruder, designated 30, extends to the housing 30 of the planetary roller part 5 approach. The extruder housing 30 is with an insert 31 connected in a bore of the housing 5 sitting. The stake 31 has two superimposed grooves on its outside 32 and 34 , Between the two grooves 32 and 34 there is a footbridge 33 , These grooves form connecting channels. There are two connection channels because the housing with a socket 22 is lined and because the jack 22 is provided on the outside and inside with a toothing. The internal toothing, not shown, is used to mesh with the revolving planetary spindles, which in 1 are shown. The external teeth form channels for the temperature control agent for heating / cooling the planetary roller part. The outer teeth of the socket 22 is through the associated hole for use 31 interrupted in two places. Each connection channel is intended for one interrupt and connects the one interrupt end to the associated other interrupt end.
The grooves 32 and 34 are due to an external tubular jacket 35 closed so that no heating medium or coolant can enter or exit incorrectly.

In the exemplary embodiment there is an inlet opening 37 the groove 34 shown. The entrance opening of the groove 32 is in a different place, not shown.
In the exemplary embodiment, the outlet opening lies on the diametrically opposite side of the insert, not shown 31 ,

The embodiment according to 4 shows the application of an extruder for foam production. This is about an insert 40 that in the extruder housing 5 sits, liquid blowing agent pumped into the plastic melt.

In the area of the socket 41 an insert, not shown, is provided, which differs from the insert 3 differs in that only one connecting channel is provided.

The 5 to 7 show another extruder with a planetary roller module with a housing 101 and a flanged side arm extruder.

The planetary roller module has an extruder housing with a bushing arranged in it. The housing is shrunk onto the socket.
The socket has milled channels on the outside for temperature control agents for cooling or heating.
The channels run helically on the outer surface of the socket and were created by milling. In the exemplary embodiment, two different temperature ranges are provided. One area is through inflows and outflows 120 . 121 characterized, the other area by inflows and outflows 122 . 123 ,

The side arm extruder is a twin screw extruder and consists of different parts. This includes two snails arranged side by side 116 which mesh with each other and are driven by a motor. Between motor and snails 116 are a gear 115 and a clutch 111 intended.
In addition, the side arm extruder is made of a filler 109 and an extrusion part 102 composed. The filler 109 has an opening for a material feed, not shown.

The side arm extruder has in the extrusion part 102 a tempered housing.
The housing has a stepped end 104 with which it is in a hole 103 that sits through the housing of the planetary roller part 101 and extends through the associated socket into the interior of the planetary roller module. The drilling causes in the area of inflows and outflows 122.123 a special guidance of the channels provided for the temperature control agent on the outside of the socket. There the channels have been led around the area of the bore so that the area around the bore is also tempered.
An additional option for temperature control in the area is the temperature-controlled front end of the side arm extruder.

The drilling leads to a contact area due to the gradation described above 102 on the housing.

The 8th to 10 show in a further embodiment a complete plant for the production of mixtures of wood particles and plastic.
It finds an extruder with a filler 201 and two planetary roller parts 202 and 203 Application. The filler 201 has the design of a single screw and corresponds in principle to the single screw or filling part of the 1 , The two planetary roller parts 202 and 203 correspond in principle to the planetary roller parts 5 and 10 the 1 ,
The filler 201 becomes a funnel 205 fed with sawdust. The wood particles are drawn into the filler and slightly preheated.
The system also includes a laterally arranged extruder 204 , The extruder on the side 204 is a single-screw extruder and is used to melt the plastic. The extruder on the side injects the liquid melt between the filler 201 and the planetary roller part 202 in the extruder.
Between the filler 201 and the planetary roller part 202 an intermediate ring is provided.

The intermediate ring is in 11 shown. In 11 are the housing of the filler 201 with 211 and the housing of the planetary roller part 202 designated 210. The two opposite housing ends are with a collar 214 and 213 Mistake. There is an intermediate ring between the two collars 212 admitted. The intermediate ring 212 is embedded in centering holes on the end faces of the collar. The intermediate ring 212 has several openings evenly distributed around the circumference, to which melt lines 216 from the extruder 204 to lead. The intermediate ring 212 is between the collars 211 and 213 braced. The bracing is effected by tensioning screws, of which only a center line 215 is shown. The clamping screws penetrate both collars and work together with screw nuts.

After the confluence of liquid melt and wood particles takes place in the planetary roller part 202 the mixing and homogenization and compression take place. In the subsequent planetary roller part, cooling takes place to a desired outlet temperature. In the exemplary embodiment, the temperature of the mixture is still so high that the mixture evaporates and loses unwanted moisture on the way.

In the exemplary embodiment, after the outlet and evaporation, the mixture is distributed to a number of further extruders. For this purpose, there is a distribution device 220 intended. The distribution facility 220 the mixture leads to three downstream single-screw extruders 221 . 222 and 223 , These single-screw extruders can be supplied with the mixture individually or in groups or all together, evenly or differently. The aim is to use different or identical profile formats with the single-screw extruders as required 221 . 222 and 223 to extrude.

In the exemplary embodiment, the distribution device is formed by a switch in the conveying path of the mixture after leaving the extruder. With the switch, the amount of mixture delivered can be diverted to certain single-screw extruders or divided into two or three streams, which are then fed to the relevant single-screw extruders.
The way to the distributor 303 is enclosed. The housing is with 302 designated. Degassing takes place on the way to the distributor and in the distributor.

The distribution according to the invention takes advantage of the gradient from a higher working level for a central production of the mixture to the lower-lying production lines.

The distributor consists of a pot-like lower part.
The lower part has an edge with which it rests on a false ceiling. In addition, the lower part protrudes down through a ceiling opening under the false ceiling.
The pot-like lower part is closed at the top with a lid. The cover can be moved in guides. The movability is used to open the distributor for maintenance and repair. In the exemplary embodiment, part of the housing is at the same time fastened to the cover and can be moved with the cover.
In addition, the cover can be partially opened to find access to the inside of the distributor without being moved.

When the mixture enters the distributor through the housing, it hits the tip of a cone. The cone is determined by the tip, its height and by its foot. The cone is rotatably arranged and provided with a drive.

As a result, the mixture slides down not only due to its gravity on the lateral surface of the cone, but also due to centrifugal force acting on the sliding mixture due to the rotation of the cone.
The cone thus forms a rotor.
The cone slides with the foot on the bottom of the pot-like part.
The mixture can collect in a space between the foot and the jacket of the pot-like part. The bottom of the distributor is open in the area of the above-mentioned channels or with outlet openings to the channels. This should cause the mixture to fall into the channels.
In the intermediate space, the mixture of arms is taken along in the direction of rotation of the cone. The arms are crescent-shaped and center the mixture on the center of the space, thus ensuring that the mixture enters the channels particularly reliably. The arms form clearers.

Depending on the volume of the distributor and the capacity of the distributor to mix, the distributor forms a more or less large buffer.

In a further embodiment is instead of the melt extruder 204 a pump, not shown, provided the melt from a Not shown melt container metered into the planetary roller extruder.

To 12 is a planetary roller extruder instead of the planetary roller extruder of the previous figures 140 with a gear / drive 141 , a filler 143 and planetary roller modules 144 and 145 intended.
At the same time there is a twin screw extruder instead of the previous addition for wood particles 147 intended. The twin screw extruder 147 is a side arm extruder. As in the other exemplary embodiments, it picks up the wood particles from a hopper which is arranged above the side arm extruder. On the way to the filler 143 the wood particles experience a desired preheating.
As in the previous exemplary embodiments, a melt is provided for the mixture with the wood particles using a side arm extruder, which is the name here 146 wearing. In contrast to the previous exemplary embodiments, the melt is fed in with the arrow 149 marked working direction of the extruder before adding the wood particles via an injection ring 142 ,

In other exemplary embodiments, part of the melt is added as in 12 shown, while the other part of the melt according to the embodiments of 1 to 11 after the wood particles have been added.

The 13 shows the injection of the melt and the abandonment of the wood particles in an enlarged sectional view. Here are of the filling part designed in the manner of a planetary roller extruder 143 and the planetary roller module 144 the housing is shown with the internally toothed bushings, which is a central spindle 151 surround. The associated planetary spindles are not shown. The housing socket of the filler 143 is with 154 designated.
The filler 143 and the planetary roller module 144 are tempered in the manner described above.

From the transmission 141 protrudes an output pin 152 in front of which the central spindle 151 is screwed. The direction of rotation of the central spindle is selected so that it runs opposite to the direction of rotation in which the central spindle screw connection is loosened. In addition, to secure the screw connection, an anchor is guided in the center of the hollow central spindle and braced with the driven pin.

To mount the filler housing and the housing of the planetary roller modules, the output pin of the gearbox is fitted with a piece of pipe 155 surround. The pipe piece 155 forms the connection between the filler housing and the housing of the planetary roller modules with the gearbox / drive.

The side arm extruder 147 is designed as a twin screw extruder. His two snails 150 protrude through an opening in the housing of the filler part up to the movement path of the rotating planetary spindles without touching them during operation.
This forces the wood particles between the rotating planetary spindles ...

14 shows a further enlarged sectional view of the injection point 142 for melt. The center line of the extruder is drawn to scale and with 159 designated.

The housing 143 of the filler and the pipe surrounding the driven pin 155 are over flanges 156 and 157 tense together. Both flanges close a ring 160 between themselves.
The ring 160 is in the direction of work / funding 149 facing end face with a groove extending over 350 degrees 166 Mistake. As a result of the groove 166 create an outer web 165 and an inner bridge 164 ,

The inner bridge 164 has a small wall thickness and ends at a distance from the adjacent end face of the housing bush 154 , This creates a gap 167 ,
The outer web 165 lies sealingly on the end face of the housing bush 154 ,
Thus arises from the ring according to the invention 166 and the housing bushing a channel for the supply of melt, the channel / ring through the gap 167 forms a device for injecting the melt.

15 shows a perspective individual view of the ring 166 with a fuse line connection 170 , which is provided centrally on the U-shaped groove. On both sides of the center of the connection, the U-shaped groove that forms the channel together with the housing socket extends over 175 degrees.
Also shows 15 connections 171 and 172 for the supply and discharge of
Tempering agent.

During operation, the melt flows through the channel-forming groove 166 and enters the melt through the gap 167 into the interior of the extruder. The melt is injected into the interior under the selected melt pressure, so that the toothed extruder parts in the filler are wetted with melt before these extruder parts come into contact with the wood particles. The melt drastically reduces the friction value of the contact surfaces of the toothed extruder parts, as long as they remain on the Touch surfaces are liable. When the melt has been removed from the contact surfaces, the melt is mixed with the wood particles. The mixture is not as abrasive as the wood particles without mixing with the melt. On the way, the service life of the toothed extruder parts can easily be extended by 20% and more.

• -einen Kanal 161 in der erfindungsgemäßen Ringkonstruktion zur Temperierung mit Wasser
• -eine mittige Ausnehmung 162 in der Stirnfläche des Ringes 160, die es erlaubt, eine oder mehrere Planetspindeln in dem Füllteil entgegen der Arbeits/Förderrichtung bis in die Ausnehmung ragen zu lassen, so dass die Planetspindeln durch die austretende Schmelze sofort getroffen werden und die Schmelze in Arbeits/Förderrichtung zur Aufgabestelle für die Holzpartikel fördern
• -eine Dichtung 158 an dem Abtriebszapfen

Otherwise shows 14

• -a channel 161 in the ring construction according to the invention for tempering with water
• -a central recess 162 in the face of the ring 160 , which allows one or more planetary spindles to protrude into the recess against the working / conveying direction, so that the planetary spindles are immediately hit by the emerging melt and convey the melt in the working / conveying direction to the feed point for the wood particles
• -a seal 158 on the output pin

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included 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.

Patent literature cited

• WO 02/103113 A [0010]
• EP 20171372 PCT [0023]
• EP 20079140 PCT [0025, 0026, 0027, 0028, 0032, 0033, 0051, 0058, 0064, 0067, 0071, 0079, 0093, 0096, 0097, 0098, 0099, 0100, 0101, 0117]
• US 6479002 B1 [0028]
• DE 102004005058 [0029]
• DE 102004005034 [0029]
• DE 10310510 [0029]
• DE 10228191 [0029]
• WO 02/103113 [0031]
• FR 2564374 A [0052]
• EP 1262294 A1 [0053]
• EP 20079140 [0057]
• EP 1297933 A1 [0064]
• EP 1262293 A1 [0065]
• DE 10356423 [0085]

Claims (18)

Manufacture of mixtures of wood particles and / or other plant particles (wood particles / plant particles) with plastic in an extrusion system, consisting of a main extruder and at least one side arm extruder, the main extruder having a planetary roller module or section designed in the manner of a planetary roller extruder, plastic particles being independent of the Wood particles / plant articles are melted, a mixture of wood particles / plant particles and plastic taking place in the planetary roller module or section, characterized in that the wood particles / plant particles are fed directly into the planetary roll module or section with the side arm extruder and the plastic melt is at least partially in front of the Addition of the wood particles / plant particles into the planetary roller module or section so that the toothed parts of the planetary roller module or - are wetted before the wood particles are added. section takes place. Procedure according to Claim 1 , characterized by a melt feed point in the direction of conveyance of the extruder before the addition of wood particles. Procedure according to Claim 1 or 2 , characterized in that the proportion of the amount of melt added before the addition of wood particles is at least 5% by weight, preferably at least 15% by weight, even more preferably at least 30% by weight and most preferably at least 45% by weight of the total amount of melt. Procedure according to one of the Claims 1 to 3 , characterized in that the distance between the melt application and the application of the wood particles is at most 1D, where D is the pitch circle diameter of the internal toothing of the planetary roller module of the main extruder and the distance between the point of the melt entry opening which is closest to the entry of the wood particles lies, and the point of the wood particle entry opening which is closest to the melt entry is measured. Procedure according to one of the Claims 1 to 4 , characterized in that when using two side arm extruders on the planetary roller module of the main extruder, both side arm extruders are diametrically opposite one another on the planetary roller module. Procedure according to one of the Claims 1 to 5 , characterized by at least one melt application point after the addition of wood. Procedure according to one of the Claims 1 to 6 , characterized by feeding the wood particles / plant particles directly onto the planetary spindles rotating in the planetary roller module or section by means of a side arm extruder. Procedure according to Claim 7 , characterized by using a twin-screw extruder as a side arm extruder, the central axes of the two screws of the screw extruder lying in a plane which runs transversely to the central axis of the main extruder. Procedure according to one of the Claims 1 to 8th , characterized by the use of a filling part which is designed in the manner of a planetary roller extruder and by injecting the melt into the filling part. Procedure according to one of the Claims 1 to 9 , characterized in that in the planetary roller module or section of the main extruder an injection ring is provided which, alone or with other extruder parts, forms a channel and / or a nozzle for injecting the melt, and the melt by means of a side arm extruder or a pump through the housing jacket of the Planetary roller module is fed into the injection ring Procedure according to one of the Claims 1 to 10 , characterized by the use of a planetary roller module composed of several pieces of the main extruder, an intermediate piece of the planetary roller module being provided for the melt application and another intermediate piece for the application of the wood particles. Procedure according to one of the Claims 1 to 10 , characterized by the use of an injection ring which is arranged between the planetary roller module of the main extruder and the drive housing or between the planetary roller module of the main extruder and another housing part. Procedure according to one of the Claims 9 to 12 , characterized by the use of an injection ring with an outlet gap along the channel as an injection ring. Procedure according to one of the Claims 10 to 13 , characterized by the use of an injection ring with a circumferential, channel-forming groove which, apart from a gap, is closed by another extruder part. Procedure according to one of the Claims 10 to 14 , characterized by a channel which extends in the ring over less than 360 degrees or is interrupted at one point, the connection for the melt feed preferably being attached centrally to the channel. Procedure according to one of the Claims 10 to 15 , characterized in that the mean gap width of the channel is at least 0.2 mm, preferably at least 0.4 mm and even more preferably at least 0.6 mm. Procedure according to one of the Claims 10 to 16 , characterized by an increase in the gap width with increasing distance from the point of entry of the melt into the channel. Procedure according to one of the Claims 10 to 17 , characterized by an expansion of at least 0.3 mm, preferably at least 0.6 mm, even more preferably at least 0.9 mm.

Images