WO1999014022A1 - Method for producing moulded bodies, moulded body and installation for carrying out said method - Google Patents

Abstract

The invention relates to a method for producing moulded bodies, especially chip boards or fibre boards, wherein a solid duroplastic is added to a defibrateable base material with a moisture content of at least 9 wt. %. The duroplastic and the base material are subjected to a treatment for gluing purposes, whereby the base material is simultaneously defibrated and mixed with the duroplastic and the glued and optionally post-treated fibre-moulding material thus obtained is shaped into a moulded body. The invention also relates to a moulded body, comprising a fibre material and a binding agent based on a duroplast which is solid at room temperature.

Description

 Process for the production of molded parts, molded part and plant for carrying out the process

It was the primary object of the present invention to provide a new process for the production of molded parts. In the context of this application, the term “molded parts” in particular also includes plates.

In the context of the invention, in particular chips and / or fiber bundles of renewable fiber-containing raw materials such as wood (in particular annual plants) and straw are used as the molding base material. This base material is also referred to below as chopped material.

The starting situation before the invention can be described as follows:

Particle boards and the like are today mainly produced using liquid resins. The chips (or fiber bundles) used are glued with liquid thermoset resins based on urea, melamine and phenol-formaldehyde resins or mixtures thereof. In addition to limited quality training, there is also the problem of the subsequent release of formaldehyde. Since the systems are aqueous at the same time, the chip moisture is increased, so that, for example, a high energy expenditure must be predried before a plate pressing process.

In some cases, one therefore switches to PMDI binders in order to be able to bind difficult raw materials and not to add any additional water.

From the practical point of view, however, the use of PMDI has been indispensable when using straw (straw chips) because the wax layer of the straw made any other binding impossible. But PMDI is not only expensive, it also poses a health hazard during processing, which means that special safety measures must be taken.

From a practical point of view, only melamine, alkaline phenolic resins and PMDI come into question from the group of liquid resins to achieve weather-resistant sheets or molded parts.

These systems are difficult to use because quick curing is required for short pressing times. The water introduced with the binders must also be evaporated (reduction of the vapor pressure), which makes the pressing process critical.

If plates that are difficult or not combustible at all are to be produced, the binders previously used in practice are also at the limit of their performance, since they make it more difficult to integrate a fire protection agent.

It was therefore a further object of the present invention to facilitate the integration of fire protection impregnation into a molded part based on chips or fibers. In this context, reference is made to the German patent application 196 21 606.0, which relates to non-combustible plates; the ideas, process steps and technical features of a non-combustible plate contained in this patent application are available to the person skilled in the art in the configuration of the present invention. You are part of this registration by reference. With the method according to the invention, it should also be possible to achieve flood and weatherproof materials (at least V 100 in accordance with DIN 68763).

The stated objects are achieved according to the invention by a process for the production of molded parts, in particular chipboard and fiberboard, in which a solid thermoset is added to a fiberizable base material with a moisture content of at least 9, preferably at least 15% by weight.

For the purpose of gluing, the thermosetting plastic and the base material are subjected to a treatment in which the base material is simultaneously defibrated and mixed with the thermosetting plastic, and the glued fiber molding material thus obtained is molded into the molded part.

Before the molding into a molded part, the fiber molding material can also be subjected to an aftertreatment as described below and / or known to the person skilled in the art in the field of molded part production.

In the method according to the invention, the base material used is surprisingly converted directly into a glued fiber molding material which can be processed into a molded part without further gluing. Obviously, two factors are responsible for the success according to the invention:

(a) the high moisture content of the base material, i.e. for example the straw chips, wood chips or the like used and

(b) defibration of the base material in the presence of the solid thermoset.

A simple mixing of the base material and solid thermoset (without fiberization) does not lead to satisfactory results any more than a two-stage procedure in which the base material is first defibrated in the absence of the thermoset and then the fiber material and the thermoset are mixed. In both cases, the processing of the base or fiber material-binder mixture, that is to say during and after the mixing of the components, leads to an unacceptable, almost quantitative separation of base or fiber material and solid binder. This suggests that it is necessary to provide the solid thermoset with sufficient amounts of freshly produced surface - and this is achieved convincingly by the simultaneous process control according to the invention. There is therefore no longer a separation problem in the method according to the invention.

The thermosets used as binders according to the invention, which are solid at room temperature and are, for example, powdery or granular, are selected from the following groups:

- phenol novolake (possibly with hardener); particularly preferred

- epoxy novolaks (possibly with hardener); particularly preferred

- melamine resins

- urea resins

- polyester resins

- other thermosetting solid resins

These resins, which are solid and almost water-free at room temperature, are mixed in a suitable dosage form (e.g. in powder form) with the base material used - e.g. straw shavings or wood fibers - possibly together with a suitable hardener.

The solid binders used according to the invention can be used without problems together with the known hardening accelerators, water repellents and release agents and similar processing aids. Graphite can also be added to accelerate the heat transfer during pressing and to facilitate homogenization when the base material / binder mixture is ground.

Unless used in the form of a dispersion, the resins listed above and used according to the invention do not bring any water with them and are distinguished by an irreversible through-hardening which can no longer be split under normal operating conditions; they withstand even the toughest changing conditions. Under the conditions according to the invention, their high fluidity and the very good anchoring ability in or on the organic raw materials enable the glueing of even difficult components, such as straw. It is also important that, even when using impregnated chips or fiber bundles as the base material - especially with chips provided with fire protection impregnation - there is no interference with the gluing. This is ensured in particular by novolak resins adjusted to these needs.

The problem of formaldehyde emission does not exist in the process according to the invention.

In the method according to the invention, the mixture of base material and thermosetting plastic is advantageously subjected to a drying treatment during or after the defibration treatment, in which the moisture content is reduced. Since solid, at least largely water-free thermosets are used as binders, such a drying treatment can be carried out comparatively inexpensively.

If necessary, the base material used is pre-shredded as far as necessary before the thermoset is added.

The base material (e.g. chips or fibers) is adjusted to a moisture content of more than 15% by weight, preferably more than 30% by weight and in some cases more than 45% by weight, before or when the thermoset is added. The adjustment of the moisture content is achieved regularly by adding water to the base material before or during the admixture of the thermoset or treating it with steam.

Sometimes it is advantageous to incorporate the thermosets used according to the invention in the form of a predominantly aqueous dispersion in the base material.

The water can contain a fire protection substance, for example a protective salt, with which the molding material is to be impregnated.

In order to achieve particularly good results, the mixture of thermoset and base material is preferably subjected to a temperature treatment simultaneously with the defibration and gluing treatment, in which the melting temperature of the thermosetting material is briefly reached or exceeded. This achieves a particularly stable fixation of the thermoset on the molding material; however, care must be taken that the thermoset does not harden prematurely. The temperature treatment and the drying treatment already mentioned can advantageously be carried out simultaneously in a single process step, for example as hot air drying.

The invention further relates to a molded part comprising (a) a fiber material (such as straw fibers) and (b) a binder based on a thermoset which is solid at room temperature.

Finally, the invention also relates to a plant for carrying out the method according to the invention and / or for producing the molded part according to the invention, in which means are provided for simultaneous defibering and gluing of a defibratable base material.

Individual aspects of the invention are first explained in more detail below with the aid of process examples.

Example 1:

Comparison of different procedures:

a) Addition of phenol novolak powder to chopped wheat straw depending on the fiber length and the moisture content (gluing without simultaneous defibration):

Wheat straw was cut in a chopper. Using conventional screening devices, the cut wheat straw (straw chips comprising chaff) was divided into 5 fiber fractions (main fractions), which are defined in Table 1 below on the basis of information on the fiber length distribution.

The bulk density of each of the 5 main fractions was determined in accordance with DIN 1306, cf. the corresponding column in Table 1 below. Each of the 5 main fractions was then divided into 3 sub-fractions, and one sub-fraction of the 15 main fractions was adjusted to a moisture content of 15, 30 and 50% by weight of water by storage in a climatic room.

Each of the total of 15 sub-fractions was mixed in a ploughshare mixer for 8 mimutes with 15% by weight of a phenol novolak powder (particle size distribution: 4%> 63 μm), with no appreciable shortening or defibration of the straw chopped material used.

Thereafter, each mixture of the respective sub-fraction and the phenol novolak powder used was sieved through a sieve with a mesh size of 100 μm, and the non-deposited phenol novolak powder was weighed out. The difference between the phenol novolak powder used and the weight weighed out corresponds to the amount of powder deposited. From this, the amount of phenol novolak powder deposited was calculated in percent, cf. the corresponding column in Table 1.

Table 1 shows that straw choppings with a small fiber length accumulate significantly more powder resin than choppings with a long fiber length. The main fraction, in which 85% of the fibers were less than 20 mm long, showed the best accumulation behavior at every moisture content. This main fraction would still be practical for technical applications. On the other hand, chopped material fractions not examined here, which essentially consist of even shorter straw particles (such as 95% <20 mm), no longer contribute significantly to their strength when further processed into a molded part.

Table 1 also shows that within each major fraction, the attachment ability for phenol novolak powder increases with moisture content. The main fraction already mentioned (85% <20 mm fiber length), with a moisture content of 50%, showed the greatest willingness to attach all of the (sub) fractions examined. Here too, however, only 46% of the phenol novolak powder used was deposited on the chopped material; 54% of the thermoset was weighed back after sieving through the 100 μm sieve.

All of the subfractions examined were otherwise very inhomogeneous glued, ie the phenol novolak powder used was not homogeneously distributed on the chopped fibers used. This inhomogeneity made the glued chopped material of each individual subfraction not particularly suitable for further processing into a molded part.

b) attachment of phenol novolak powder to chopped wheat straw with simultaneous defibration and gluing; Dependency of the accumulation on the moisture content of the base material:

As described under a) above, wheat straw was cut and fractionated in a chopper.

A single fraction with a fiber length distribution of 85% <60 mm and 26% <20 mm was examined. This corresponds to the third main fraction according to Table 1.

The fiber fraction was divided into 4 sub-fractions, and each of these sub-fractions was adjusted to a moisture content of 8, 15, 30 or 50% by weight of water, as described above under a), see Table 2.

Each of the 4 sub-fractions was treated in a fiberizing mill for 8 minutes with 15% by weight of a phenol novolak powder.

After passing through the mill, each glued subfraction was dried back to a moisture content of <6% by weight and the fiber length distribution and the bulk density were determined.

The (first) subfraction with a moisture content of 8% by weight was fiberized in the fiberizing mill on the one hand, but on the other hand there was also a considerable shortening of the fibers, so that 95% of the straw fibers had a length of less than 20 mm after passing through the mill (according to initially 26%). The bulk density of the glued fiber material of the first subfraction was 0.1 g per liter (see Tab. 2) compared to 0.35 g per liter for the non-glued chopped material (see Tab. 1).

By reweighing the phenol novolak powder (as described under a) it was determined that 86% of the powder used adhered to the fiber material had accumulated.

The sub-fractions with a moisture content of 15, 30 and 50% by weight were investigated in an analogous manner. It was found that the fiber shortening decreased sharply towards higher moisture contents, while the splitting of the straw particles used in the longitudinal direction, i. H. their fraying came to the fore. At the same time, the bulk density of the glued fiber material (after passing through the mill) decreased towards the sub-fractions with a high moisture content.

The subfractions with 15, 30 and 50 wt.% Moisture were very good, but the best values were achieved with the subfractions with a moisture content of 30 wt.% And 50 wt.%, In which 98% or 99% of the resin used was added.

Summary and evaluation:

In comparison to the test procedure according to a), under b) each individual subfraction was not only mixed with the thermoset, but also fiberized at the same time. This led to a surprisingly strong increase in the readiness for attachment for the thermosets used, which is probably due to the provision of a fresh surface due to fiberisation and an associated reduction in the proportion of the surface coated with wax in the available total surface.

Comparing, for example, the glued fiber material according to Table 1, fourth main fraction (40% <20 mm), sub-fraction with moisture content 30% with the product according to Table 2, third sub-fraction (fiber length after the mill 42% <20 mm, moisture content 30%) , it can be seen that in the course of the process according to the invention according to b) an almost complete (98%) accumulation of the thermoset used has taken place, while in the process not according to the invention according to a) only 25% of the thermoset has been accumulated.

When the process was carried out according to the invention, the respective product was a uniformly glued fiber molding material, while when the process was not carried out according to the invention, an inhomogeneously glued product was obtained in each case. Tables for example 1:

Addition of 15% w / w phenol novolak powder to wheat straw

Table 1

Table 2

Bei spiel 2 :

Example 2:

Process example: Resin dosing without impregnation with protective salt

a) Downstream comminution and / or homogenization treatment:

Pre-shredded wood chips (chopped material / base material) with a moisture content of approx. 80% by weight are conveyed in a quantity of 10 t / h atroot through a dosing screw to a fiberizing mill. In this way, 10% or 1 t / h novolak powder resin is added and premixed using a dosing scale.

The downstream mill shreds the chopped material and promotes the mixing of the components. A glued fiber molding material is formed.

This glue-coated fiber-form material ( "chip / fiber-resin mixture") is fed to a drum dryer in a conventional manner, which is set to an off ^¬ inlet temperature of about 90 ° C. The exit moisture is then still about 2% and the resin has been melted. The further cooling that occurs leads to a particularly strong bond between the fiber and the resin grain.

A subsequent forming station forms a nonwoven for sheets ^¬ thickness of 20 mm with a density of 680 kg / m ^3. This feeds a heating press, where pressing takes place at temperatures of 220 ° C with a heating time factor of 10 sec / mm and the Duro ^¬ plast hardens. The plates produced are processed in a known manner.

b) Simultaneous procedure:

Procedure as in a), but this time the novolak powder resin is metered in directly into the inlet zone of an appropriately designed fiberizing mill. Process example: Resin dosing with protective salt impregnation

a) Downstream comminution and / or homogenization treatment:

Straw bales are broken up and crocheted to a length of approx. 60 mm. The crochet egg (base material) with a moisture content of approx. 12% is transported in a throughput rate of 6 t / h atro by an impregnation screw. In the inlet zone of this screw, an aqueous fire protection agent is added in a quantity of 30% protective salt as a 40% solution and mixed with the straw chips. Another dosing device takes over the conveying of the impregnated chopped material to a fiberizing mill via a discharge screw. 15% or 900 kg / h of novolak powder (resin) are metered in and distributed homogeneously on this route. The mixture has a moisture content of approx. 50%.

The mill is equipped with reaming jaws and takes care of the shredding of the straw chips, the homogenization and the gluing.

The glued fiber molding material then passes through a current dryer with an outlet temperature of approx. 75 ° C. The drying takes place to a humidity of approx. 6%. At the same time, the Novolak resin powder - adjusted to these conditions - is particularly firmly fixed on the straw fiber.

A fleece for a plate thickness of 8 mm with a density of 750 kg / m ^{3 is} produced in a downstream scattering station. A heating press compresses the fleece into sheets and cures the resin at temperatures of 190 ° C with a heating time factor of 15 sec / mm. The plates are further processed in the usual way according to the prior art.

b) Simultaneous procedure:

Rice straw is cut to a length of, for example, 40 mm. The chopped material obtained in this way comprises approximately 8% by weight of moisture and is metered into a vacuum impregnating machine in an amount of 4 t / h there impregnated with an aqueous 40% fire protection agent at approx. 25 mbar for at least 5 minutes. The protective salt intake is about 25-35%.

A dosing silo equipped with a discharge device takes over the feeding of the impregnated chopped material with a moisture content of now approx. 40% into a subsequent fiberizing mill.

This mill also has a metering device for powder resins in the inlet area. During the digestion process, a total of 12% novolak resin, i.e. H. 480 kg / h distributed over the straw material (chopped material or fibers formed from it). In the mill, the straw material is mixed, defibred and glued simultaneously.

The mill is advantageously operated with air. This takes over the transport of the raw materials (rice straw chips / fibers, resin) through the mill to a combined separating filter system. Hot transport air is preferably used so that the moisture is expelled and at the same time the resin is particularly firmly fixed to the fibers at an outlet temperature of, for example, approximately 80 ° C.

The glued and dried fiber molding material then has a moisture set for the pressing of, for example, approximately 8%. During the web formation in a scattering station occurs no Separie ^¬ tion of a resin and fibers, so that a homogeneous cross-section is achieved. A plate 30 mm thick and 350 kg / m ³ density is produced with this material. For this purpose, a heating press with a heating plate temperature of 170 ° C is used and a heating time factor of approx. 20 sea. / mm adhered to.

The plates produced are processed as usual.

In the manner described, plates can be produced for all areas of application. A particular suitability is for the construction sector with its given high quality requirements. The panels glued using Novolak meet all requirements for use in damp rooms.

In the "fire protection version" they are approved by the building authorities and can be used wherever high fire resistance classes are required.

A plant according to the invention is designed in such a way as the required process management requires; such an adaptation is easily possible for the person skilled in the art. Among other things, it will be based on the above process examples, which can also be expanded.

An important aspect in the design of a system according to the invention is that no resin should be lost in the simultaneous defibration and gluing step according to the invention, which is why a suction and air transport system which may be provided is advantageously designed as a ring line or as a dryer-recirculation system.

Preferred embodiments of the system according to the invention for carrying out the method according to the invention are explained below with reference to the figures. They represent:

Fig. 1 basic flow chart to explain preferred embodiments of the system according to the invention. Fig. 2 plant for the production of chipboard (flow diagram) Fig. 3 plant for the production of single-layer boards (flow diagram), with a device for moistening dry chips / fibers before the addition of resin Fig. 4 plant for integrated gluing, defibration and drying of molding material (flow diagram )

In the basic flow diagram according to FIG. 1, with the exception of a fiberizing device according to the invention, all system parts are drawn undifferentiated as squares. Alternative configurations of the system according to the invention and of the method according to the invention are identified by capital letters. 1, chopped material (base material) is conveyed from the left into a device 1 for moistening and / or impregnating the chopped material. There it is mixed with water (or an aqueous fire protection agent solution) that comes from a water source (or a fire protection agent tank) 2. In the moistening device 1, the chopped material is adjusted to a moisture content of over 30% by weight of water. (Note: The chopped material will always be treated with a fire protection solution if fire-protected plates are to be produced. When using a vacuum impregnation process, the impregnation is particularly intensive and it saves on impregnation agents compared to normal pressure processes.)

To set suitable moisture ratios, depending on the specific requirements of the individual case, it can be particularly advantageous to design the humidification device in such a way that one of the following process steps can be carried out:

Moisten the chopped material (as the base material) with water by spraying. This can be done in the air flow as well as in a screw conveyor or a continuous mixer.

Moistening the chopped material with steam (low pressure steam), which can be done in a similar way as with water. Steam has the advantage that a quick, good distribution in the chopped material takes place and the accumulation is further supported by the heat carried along.

After moistening, the chopped material is then conveyed to an addition station 3 in accordance with an important alternative A and mixed with a solid thermoset which is added from a container 4. From the station 3, the mixture of moist chopped good and solid thermoset is conveyed to a defibration system 5, in which the simultaneous defibration and gluing treatment according to the invention is carried out.

According to an alternative B, the solid thermosetting plastic is not added to the chopped material in a separate addition station 3 but already in the moistening device 1. The material mix of chopped good and firm Thermosets are then transported from the moistening system 1 into the defibration system 5.

According to a further alternative C, moistened chopped good and solid thermoset are conveyed simultaneously or successively into the defibrillation position 5 and only mixed there. A separate addition station 3 is also omitted here. What is common to the configurations according to alternatives A, B and C is that a permanent bond between the molding material, ie. H. the chopped material crushed into fibers, for example, and the solid thermoset is produced.

According to an alternative D, the glued molding material is conveyed out of the defibration plant 5 into a drying plant 6, in which the moisture content of the now glued fiber material is reduced. The glued fiber material is brought from the drying plant 6 into a plant 7 for forming a molding material fleece. The nonwoven produced in the nonwoven formation plant is finally further processed in a plant 8 for the production of molded parts, for example a plate pressing system, to form a molded part.

According to an alternative embodiment E, the drying treatment is not carried out in a separate drying system 6 but already in the defibration system 5. So it is a combined fiberizing, gluing and drying system.

It is clear that only the essential plant elements and process steps are shown in the basic flow diagram according to FIG. 1. Plant elements, not shown, are, for example, conveying devices, dust removal plants, transport plants, cyclones and the like.

The configurations of a system according to the invention described with reference to FIG. 1 naturally correspond to corresponding configurations of the method according to the invention. In a typical embodiment of the method according to the invention, the introduction and attachment of the powder resin binder to avoid separation from the molding material thus takes place in the following steps, which correspond to alternative A: Step 1

The vegetable fiber raw materials (as the base or primary material for the molding material) are chopped and moistened (in the moistening device 1) and, if necessary, impregnated.

step 2

Solid powder resin (from the container 4) is still wet or (in the adding station 3) with the optionally. Chaff mixed well impregnated desired weight ratio ge ^¬. (If using the naturtrocke ^¬ nen (air-dry) raw materials which are not to be impregnated later, powdered thermosets is for example. No asset- approximately promoting state.)

step 3

The premix obtained in this way is transported from the addition station 3 to the defibration system 5, which is, for example, a special defibration mill which is operated in a continuous process; there the chopped material is shredded in the manner according to the invention and glued with the thermoset.

Step 4

The fiber molding material obtained according to step 3, which is still moist (impregnated) and now glued, is dried (in the drying installation 6 according to alternative D or according to alternative E still within the defibration installation 5), the required press moisture being adjusted and, if necessary, a further fixation of the thermoset takes place on the molding material.

By means of this process design, the subsequent operations such as fleece formation and pressing can be carried out without the disadvantages described above for the processes customary today.

Steps 2 and 3 can advantageously be carried out simultaneously. This corresponds to alternative C of the basic flow diagram according to FIG. 1. Steps 3 and 4 can also be carried out simultaneously. This corresponds to alternative E. In a particularly inexpensive variant, steps 2, 3 and 4 are carried out simultaneously. This corresponds to a combination of alternatives C and E.

If, for example, according to alternative C, steps 2 and 3 are carried out simultaneously, the attachment of the powder resin to the molding material is particularly promoted.

If steps 3 and 4 are carried out simultaneously according to alternative E, a particularly good resin fixation on the molding material is achieved. Step 4 can also be carried out simultaneously with a temperature treatment.

Particularly good results can be achieved if a chamfering device is used to carry out step 3 (possibly simultaneously with steps 2 and / or 4), which directly sifts or classifies the fiber molding material glued with the thermosetting plastic and adds it exceed a certain particle size or length again the crushing process (grinding process) fed. The design of the defibration system 5 as an internally classifying comminution device leads to a particularly good homogenization of the glued molding material.

In the plant according to the invention shown in FIG. 2, straw bales are placed in the straw bale shredder 51. There they are shredded (shredded) and then conveyed into a dosing silo 53 by means of a carrying chain conveyor 52. The shredded straw is then conveyed in metered form onto a discharge metering screw 54, and a fire protection impregnation solution is added to the straw molding material in the inlet zone of the impregnation screw 21 from a fire protection agent big bag 22, which is assigned a dissolving station with metering. After the impregnation, the impregnated molding material is transported into the dosing silo 55 (volume: 50 m ³ ) with screw discharge 23.

The impregnated and therefore moist straw molding material on the screw discharge 23 is mixed with a powdered thermoset (powder resin) according to the invention, which is fed from a powder resin big bag 24 with a metering station. The molding material mixed with the powder resin is weighed on a roller belt weigher 56 and then into the fiberizing mill 25 promoted. The defibration and gluing according to the invention takes place there.

Following this step, the molding material in the stream is ^¬ dryer 26 dried. Drying takes place to a humidity of, for example, 6%. At the same time, the resin powder - adjusted to these conditions - is fixed on the molding material fibers or chips.

After emerging from the current dryer 26, the molding material is conveyed into a scattering bunker 27 (with discharge device), which creates a fleece from the straw molding material and deposits it on a molding belt 57 with a basis weight scale 58. The fleece passes on the belt 57 to a nonwoven separation and extraction unit 59 and then finally reaches a pressing-Be ^¬ send ribbon (a-daylight press for example) 60 for conveying the straw-mat in a heated press 28th The fleece is then compressed into a plate in this heating press and the thermoset is cured. Finally (after passing through the heating press), the finished plates are taken to a take-off belt 61 and from there to a lifting table 62.

In the system shown in Fig. 3, bales of molding material (e.g. straw or hemp bales) are conveyed by means of a bale conveyor into a bale shredder 63, where they are torn. The molding material fibers or shavings are applied from the bale ripper to a belt conveyor 64, to which an overband magnet 65 is assigned. From the belt conveyor, the molding material arrives in an impact hammer mill 66, where the fibers or chips of the molding material are pre-shredded.

A desired moisture content of the molding material is set in a downstream humidification system 31; moistening can take place, for example, by injecting water or by means of steam.

An air transport system conveys the moistened, comminuted form mate rial ^¬ a silo housing 67, to which a discharge device 68 is associated with metering screw. The molding material passes through a metering trough into a fiberizing machine 35b, for example an ultrafibrator or refiner. Here (pre-) defibration takes place.

An air transport system then conveys the molding material into a floating dryer 36 with control and gas surface burner, where the molding material is dried to a desired degree of moisture if necessary.

The molding material is conveyed from the additionally sifting floating dryer 36 to a reversing screw 69, which is operated in the event of a fire against the usual conveying direction in order to keep burning items of transport away from the other system elements. The molding material then passes through a screening machine 70.

By means of a further air transport system, the molding material then reaches a silo housing 71, to which a discharge device 72 with a metering screw and - subsequently - a belt scale 73 are assigned. From there, the molding material reaches a second fiberizing machine 35a, where it is mixed and homogenized with a thermoset according to the invention, which is fed from a glue preparation and metering system 34.

According to an important alternative system design, the system elements of belt weigher 73, second fiberizing machine 35a and glue preparation and metering system 34 are omitted. The thermosetting plastic is then added in the form of a dispersion in the humidification system and the fiberizing and gluing according to the invention takes place in fiberizing machine 35b.

The molding material glued with the thermoset according to the invention is conveyed by means of a trough belt conveyor or an air transport system (as an alternative to the belt conveyor) into a litter bin 37 which has a molding head for forming a fleece.

The binder-containing molding material emerges from the molding head in the form of a fleece and is moved between scattering walls on a molding belt 74 with a chain conveyor and press feed chain conveyor; a basis weight scale for controlling the spreading hopper is assigned to the forming belt. A cross-cut saw (210 mm) 75 with a catcher cuts this Nonwoven to the desired format and a metal detector located behind it detects any metal contamination of the nonwoven. If metal is detected, a faulty scattering system 76, which interacts with an extraction system, removes the faulty nonwovens.

The nonwovens are finally fed to a press system 38, which, however, is preceded by a surface spray system 77, in which water or release agent is sprayed onto the nonwovens. Plates according to the invention are produced in the press system. Conventional further processing devices follow the press system, cf. also Fig. 2.

In the system for integrated gluing, defibration and drying of molding material shown in FIG. 4, a transport screw 78 for pre-crushed molding material (for example pre-crushed straw) is shown, which conveys it onto a dust sieve 79. The molding material is largely dedusted here.

The pre-comminuted molding material is then conveyed in a metered manner on an impregnating screw 41, and a fire protection impregnating solution is added to the molding material in the inlet zone of the impregnating screw 41 from a metering station 42, which is assigned a dissolving station with metering. The impregnation takes place on the impregnation screw at a reduced pressure of, for example, 25 mbar. After impregnation, the impregnated molding material is transported into the dosing silo 80.

The molding material is weighed on a downstream roller belt weigher 81 and then conveyed into an ultra-rotor defibration mill 45 with an integrated classifier, a metering screw 82 and a hot air device 83 (for drying and temperature treatment). Simultaneously with the conveying of the molding material into the fiberizing mill 45, powder resin is fed into the fiberizing mill via the metering screw 82 from a metering station 44. Means 84 are provided which have the effect that the mass of molding material conveyed into the mill per unit of time and the mass of powder resin introduced are at least approximately in a predetermined relationship to one another. For example, the weighing signal of the roller belt weigher 81 can be used as a reference signal in order to specify the amount of powder resin that flows from the powder resin metering station 44 via the Dosing screw 82 to be entered in the fiberizing mill 45.

In the fiberizing mill 45, the molding material is simultaneously fiberized, glued with powder resin and dried. Drying is carried out by means of hot air flowing through, which is generated, for example, in a heating register 29 and introduced into the mill from below.

The mill 45 comprises means for screening or classifying the in their befindli ^¬ chen molding material (in its glued or unbelei th state). ^¬ rough portions are sifted in the head of the machine and returned to the grinding circuit in a lower inlet region. In this way, stalk knots and the like can also be undone, which is why a separate sifter can also be dispensed with.

The finished glued and dried molding material fibers are conveyed into a separator 85 for dry fibers. From there, they finally reach a dosing silo (litter bunker) 47, where a fleece is produced from the glued molding material, for example by means of an associated spreading device.

Claims

Expectations: 1. A process for the production of molded parts, in particular chipboard and fiberboard, in which a solid thermosetting plastic is added to a fiberizable base material with a moisture content of at least 9% by weight, thermosetting plastic and base material are subjected to a treatment for the purpose of gluing, in which the Base material is simultaneously defibrated and mixed with the thermoset, and the glued and optionally post-treated fiber molding material thus obtained is molded into the molded part. 2. The method according to claim 1, characterized in that the mixture is subjected to a drying treatment during or after the simultaneous defibration and gluing treatment. 3. The method according to any one of the preceding claims, characterized in that the base material is crushed prior to the admixture of the thermoset. 4. The method according to any one of the preceding claims, characterized in that the base material is adjusted to a moisture content of over 30%, preferably over 45%, before or during the admixture of the thermoset. 5. The method according to claim 4, characterized in that the setting ^¬ ment of the moisture content is achieved by adding the base material before or during the admixture of the thermoset with water. 6. The method according to claim 4, characterized in that the setting ^¬ ment of the moisture content is achieved by treating the base material with water vapor before or during the admixture of the thermoset. 7. The method according to any one of the preceding claims, wherein the thermoset is added to the base material in suspended form. 8. The method according to any one of the preceding claims, characterized labeled in ^¬ characterized in that the mixture of thermosetting plastic and the base material is preferably subjected simultaneously with the defibration and Beleimungsbehandlung a temperature treatment, in which reaches the melting temperature of the thermosetting resin or exceeded. 9. The method according to any one of the preceding claims, characterized in that the fiberizable base material comprises chips or fiber bundles of fiber plants. 10. The method according to claim 9, characterized in that the defibratable base material comprises straw chips. 11. The method according to any one of the preceding claims, characterized in that the base material is treated with a fire protection agent. 12. The method according to claim 11, characterized in that the treatment ^¬ treatment with the fire retardant takes place under reduced pressure. 13. molded part comprising a fiber material and a binder based on a thermoset which is solid at room temperature. 14. Plant for carrying out the method according to any one of claims 1-12 and / or for producing the molded part according to claim 13, characterized in that means are provided for simultaneous defibering and gluing of a fiberizable base material.