EP1247916B1 - Insulating element, particularly insulating board, made of wood fibre - Google Patents

Abstract

The insulating board is formed on a base of fibers with ligno-cellulose content and adhered by a binder. The fibers (2) in the insulating board have a preferred orientation parallel to a plane (9) extending at right angles to the front (3) and rear (4) surfaces. The front and/or rear surface are open natural joints. At least one narrow face (6) of the insulating board which extends parallel to the plane of preferred orientation is constructed at least partially from a closed pressed surface of hard fiber board. Independent claims are included for a procedure of the manufacture of insulating components in the form of hard fiber boards, and for a use for the insulating components which can be fitted on a wall or on the underside of a ceiling.

Description

The invention relates to an insulating molding, in particular an insulating board, with the features of the preamble of claim 1. Furthermore, the invention relates to a method and uses of such insulating moldings.

Different insulating materials are used in the building industry A special category of these insulating materials is wood fiber board insulation boards. These include so-called wood soft fiber boards, which are traditionally produced mainly by so-called wet process. As a more general, independent from the manufacturing process designation "factory-made wood fiber insulation" is used, which term includes not only plates but also rolls.

The present invention relates to insulating moldings having substantially fixed outer dimensions, including in particular insulation boards, in which the front surface and the rear surface, with which the insulation board starts and ends in the insulation direction, run parallel to each other. But the insulating moldings may also have a deviating spatial form.

A special known application of insulation boards according to the preamble of claim 1 are so-called external thermal insulation systems. These are based, for example, on a bond between an insulating layer of the insulating boards and a weatherproof layer, which can usually be a mineral plaster. Such a thermal insulation composite requires a high intrinsic strength of the insulating layer, since only this carries the weather protection layer. In another known thermal insulation composite system is applied to insulation boards according to the preamble of claim 1, a flexible soft facing shell. Specifically, a Gigskarton- or gypsum fiber board is glued with a Ansetzbinder directly on the insulation board. The insulation board can be mounted both on a wall as well as hanging on the underside of a ceiling, which is also possible by gluing with a Ansetzbinder. In addition, it is also known, the insulation boards in thermal insulation systems one or both sides with higher-strength materials to plank, which can be designed decoratively and also very thin.

In all known uses described heretofore, the front surface and the rear surface with which the insulation boards begin and end in the direction of insulation are formed by the natural broad sides of the insulation boards, as originally produced in the manufacture of wood pulp boards by bonding the lignocellulosic fibers have arisen.

Regarding the requirements for the inherent strength of the insulation boards, all applications described here have in common that a sufficiently high resistance to breakage of the insulation board of the Wall or ceiling must be given on the one hand and the applied to the insulation panel on the other hand. The requirements for this resistance to breakage are defined in DIN 68755-1 "Wood fiber insulating materials for construction" of June 2000, in which so-called break resistance groups were introduced, which are relevant for the applicability of wood fiber insulating materials as a plaster base. Decisive is the tear resistance determined perpendicular to the normal plane of the plate, which is classified into eight resistance to breakage groups. The three highest tear resistance groups listed in DIN 68755-1 are designated T15, T20 and T30. These meet the requirements for the mean value of the resistance to theft of ≥ 15 kPa; ≥ 20 kPa and ≥ 30 kPa. In order to increase the tear resistance of an insulating board of wood fiber material, the compression of the fibers in the insulating board must be increased. This in turn runs counter to the thermal insulation capacity of the insulating board. As a result, with known insulation boards made of wood fiber material, whose heat conductivity is the requirement to make that it does not exceed 0.060 W / m * K, and therefore only a certain compression of the fibers, a maximum tear strength of about 30 kPa achievable. A clear exceeding of this value is not possible. Accordingly, no higher tear resistance group T40 or the like was defined in the DIN.

Wood fiber insulating materials are in direct competition with insulating boards made of mineral or glass fibers. For the application area as plaster base, there is a special insulation board made of mineral fibers with special tear-off resistance, which is referred to as lamellar plate. A lamella plate is produced by first producing a starting plate of mineral fibers whose thickness corresponds to the later width of the lamella plate. From the output plate then strips are sawn, which correspond to the lamellar plates. That is, the width of the strips forms the thickness of the lamella plates. The front surface as well as the rear surface, with which the lamellar plate starts and ends in the direction of insulation, are sawn surfaces. In addition, the mineral fibers in the Lamellar plate has a preferential orientation parallel to a transverse to the front surface and transverse to the rear surfaces extending plane, resulting from the original preparation of the starting plate of the mineral fibers. For the tear resistance of lamellar plates, a value of ≥ 80 kPa is usually specified. The typical plate format of lamellar plates is 120 cm in length, 20 cm in width and a selectable thickness typically in the range of a few centimeters.

Lamella plates of the type mentioned above are already assumed to be known in DE-A-25 03 123. In this case, slat plates are additionally described in which a plurality of fiber slats on the basis of mineral fibers are arranged side by side between cover layers and adhesively bonded thereto.

The object of the present invention is to show insulating moldings according to the preamble of claim 1 and a thermal insulation system using such insulating moldings in which a tear-off is achieved in the same order of magnitude as lamella plates of mineral fibers with low thermal conductivity to wood fiber insulation for construction competitive do. Such an insulating molding according to the preamble of claim 1 is e.g. from EP-A-1059152 (by the same Applicant).

This object is achieved in an insulating molding by the features of claim 1. Advantageous embodiments of the Dämmformkörpers are described in the subclaims 2 to 11.

In the new insulating molding, which is in particular an insulating board, so that these two terms are also used interchangeably synonymous, have the lignocellulosic fibers from which an insulating molding essentially consists, a preferred orientation parallel to a transverse to the front surface and transverse to the rear surface extending level. The preferential orientation is thus perpendicular to the typical preferred orientation of fibers in a known insulating board of wood fiber material, which is aligned parallel to the front surface and the back surface. This special preference orientation of the fibers in the new insulating molding, which can also be referred to as a ridge-oriented fiber structure, the tensile strength of the new insulating molding, resulting in its tear resistance in a composite system, over known insulation boards

Wood pulp dramatically increased and easily achieved the values of known lamellar plates made of mineral fibers. This is due to a multiple overlap of the fibers with resultant mutual anchoring, which results only in the directions of preferential orientation, one of which coincides with the direction of the tensile load in the new Dämmformkörper. In this direction, the new insulating molding also has a good compressive strength, if it is not local, d. H. selective pressure stresses is. As with a lamella plate made of mineral fiber in the new Dämmförmkörper the front surface and the rear surface, with which the insulating body starts and ends in the direction of insulation, can not be closed surfaces. Rather, these are open interfaces that do not withstand local pressures in many places. Closed surfaces can be found in the new insulating molding only on narrow surfaces. These closed surfaces are parallel to the plane of preferential orientation.

The closed surfaces of the Dämmformkörpers are preferably closed pressing surfaces, resulting from the production of a wood fiber board, which serves as the basis for the new insulating molding.

Such a wood pulp board as the basis for the new insulating molding must normally have a thickness which corresponds to the width of the insulating molding. Based on a desired width of the insulating molding of about 20 cm, it may be useful to produce the corresponding thickness of the wood pulp board in two steps. Thus, two wood fiber boards with a respective thickness of 10 cm can be glued flat to achieve a starting plate with a thickness of 20 cm. From this, then the new moldings can be cut out. This results in at least one parallel to the plane of the preferred orientation extending inner adhesive surface in the insulating molded body to which the pressing surfaces of the two wood pulp plates are glued together. This principle can also be implemented with three or more wood pulp plates. However, it is preferred if only two wood pulp boards are glued together or the plate thickness of each wood pulp board from which the new insulating molding is made, is at least 80 mm.

The density of the wood pulp boards for the production of the new insulating molding should be in the range of 100 to 230 kg / m ³ . In this area stable wood pulp plates with low thermal conductivity can be produced.

The thickness of the new insulating molding, d. H. the distance of the front surface from the back surface is typically 50 to 400 mm. But he is in principle freely selectable. He can, but in particular must not be constant. Rather, between the front surface and the rear surface of the Dämmformkörpers a wedge angle can be provided, which has advantages, for example, in the insulation of roofs. A special insulating body for insulating flat roofs has a non-angle <20 °.

It should be understood that the plane of preferential orientation in an insulating molding having a wedge angle between the front surface and the back surface may not be perpendicular to both the front surface and the back surface. This is basically not mandatory. It is sufficient to have a transverse orientation of the preferred orientation of the fibers to the front surface and the rear surface, wherein the angle between the plane of the preferred orientation of the surfaces is only about 90 °, ie in the range of 60 to 120 °. So also insulating moldings with parallel front and rear surfaces and narrow surfaces in the form of pressing surfaces with diamond-shaped instead of rectangular Querschitt are conceivable.

With such diamond-shaped cross-section can be avoided by joining the Dämmformkörper the formation of perpendicular to the insulating layer extending light gaps. Another Avoidance of light gaps can be achieved by providing two opposite narrow surfaces of the new insulating molding with complementary Stufenfalzen.

The new insulating molding may be formed as an insulating board with the usual standard dimensions, so that the front surface and the rear surface have a running in the plane of the preferred direction length of 600 to 1500 mm and a perpendicular thereto extending width of 150 to 300 mm. These dimensions include the standard dimensions of 1200 mm length and 200 mm width.

The readily achievable tear-off strengths of the new insulating molding between the front surface and the rear surface, which are glued in composite systems with support surfaces, is readily at least 100 kPa, even if a relatively low average bulk density of the insulating molding. given is.

Already in the description of the new Dämmformkörpers attention was drawn to details of its production. Basically, it is assumed that a wood pulp board, which is perpendicular to outwardly directed pressing surfaces on which the lignocellulosic fibers are densified above average, is separated along separating surfaces. At these interfaces arise the front surfaces and the rear surfaces of the insulating moldings. Typically, the cutting of the fiberboard in the new process is achieved by sawing.

The open structure of the front surfaces and back surfaces produced by sawing is indeed local Resistant to pressure. However, an excellent anchoring possibility of pasty adhesives is achieved. So the instantaneous adhesion of the new insulating moldings when sticking to ceilings and walls so well that they need only be pressed and then released, without falling down again.

If the desired width of the insulating moldings can not be provided by the thickness of a single wood pulp board, several wood pulp plates can be glued flat over their pressing surfaces together before the separation of the multilayer wood fiber board thus formed is carried out in the individual insulating moldings.

The surface bonding of the wood pulp plates can be done with a dispersion adhesive or alkali silicate. The closed pressing surfaces of the wood pulp boards allow permanent bonding using very small amounts of glue.

Inventive thermal insulation systems using the new insulating moldings are defined in claims 12 and 13. Advantageous embodiments of these thermal insulation systems can be found in the subclaims 14 and 15.

In a first thermal insulation system according to the invention, the individual insulating moldings are arranged close together, their front surfaces and their rear surfaces coinciding. Ie. A closed layer is formed from the insulating moldings which, over the entire plane of the layer, have the same composition exclusively of the fibers of the insulating moldings and the binding agent which binds them together.

In a second thermal insulation system according to the invention, the individual insulating moldings are arranged next to each other in a gap, their front surfaces and their rear surfaces again each coincide. In this case, free spaces between the Dämmformkörpern but filled with other insulating materials, which may be wood fiber insulation as rolled or other insulating materials.

Preferably, the individual insulating moldings are glued with their rear surface to a wall or ceiling. This creates a very stable connection through the open rear surface of the new insulating mold, because the adhesive can partially penetrate into the surface.

On its front surface, the insulating moldings can be covered with a plaster or a plate-shaped planking. Again, there is a very stable connection due to the open structure of the surface. The stability is not only mechanical, but also given to the weather. Here, too, the open structure of the surfaces of the new insulating molding makes positive, because once occurred moisture can escape easily and does not jam under a closed cover layer.

Fig. 1

einen Querschnitt durch eine erste Ausführungsform des neuen Dämmformkörpers,

Fig. 2

einen Querschnitt durch eine zweite Ausführungsform des neuen Dämmformkörpers,

Fig. 3

einen Querschnitt durch eine dritte Ausführungsform des neuen Dämmförmkörpers,

Fig. 4

einen Querschnitt durch eine vierte Ausführungsform des neuen Dämmformkörpers,

Fig. 5

eine Draufsicht auf den Dämmformkörper gemäß Fig. 2,

Fig. 6

die Herstellung des neuen Dämmformkörpers in der Ausführungsform einer der Fig. 1 und 2,

Fig. 7

eine erste Verwendung von neuen Dämmformkörpern,

Fig. 8

eine zweite Verwendung von neuen Dämmformkörpern und

Fig. 9

eine dritte Verwendung von neuen Dämmformkörpern.

The invention will be explained in more detail below with reference to concrete exemplary embodiments and described, in which shows

Fig. 1

a cross section through a first embodiment of the new insulating molding,

Fig. 2

a cross section through a second embodiment of the new insulating molding,

Fig. 3

a cross section through a third embodiment of the new Dämmförmkörpers,

Fig. 4

a cross section through a fourth embodiment of the new insulating molding,

Fig. 5

a top view of the insulating molding according to FIG. 2,

Fig. 6

the production of the new insulating molding in the embodiment of one of FIGS. 1 and 2,

Fig. 7

a first use of new insulating moldings,

Fig. 8

a second use of new insulating moldings and

Fig. 9

a third use of new insulating moldings.

The insulating molding 1 shown in Fig. 1 in cross-section transverse to its main extension direction consists of lignocellulose-containing. Fibers 2, which are bound with a binder not shown here separately. The insulating molding 1 has a front surface 3 and a rear surface 4 - on, wherein the assignment front and rear is initially arbitrary. It is crucial that the insulating molding 1 with the front surface 3 and the rear surface 4 in an insulating direction 5, which is perpendicular to the surfaces 3, 4, begins or ends. The front surface 3 and the rear surface 4 are sawn separating surfaces with a relatively open surface structure. In contrast, the molded body 1 at its two visible in Fig. 1 narrow surfaces 6 closed pressing surfaces 7, where the fibers 2 have a compression above the average density of the molded body 1 addition. The typical width of the insulating molding 1, which can also be referred to here as insulation board because the surfaces 3 and 4 are parallel to each other, is 20 cm, the thickness in the direction of the insulation 5 a few centimeters, here it is 8 cm. The fibers 2 in the insulating molding 1 have a preferential orientation parallel to a plane 9, which is aligned transversely to the surfaces 3 and 4. Specifically, the orientation is perpendicular to the surfaces 3 and 4. Thus, the plane is parallel to the direction of insulation 5. Furthermore, it runs perpendicular to the plane, ie parallel to the narrow surfaces 6. This is based on the fact that the preferred orientation of the fibers 2 ultimately of a Pressing comes about, over which the pressing surfaces 7 were formed. The preferred orientation of the fibers 2 in parallel to the plane 9 gives the molded body 1 a special tensile strength in the insulation direction 5 between the surfaces 3 and 4. Here, a good compressive strength is given, although this is not locally due to the open structures of the surfaces 3 and 4.

The molded body 1 according to FIG. 2 differs from that of FIG. 1 in that an inner adhesive surface 10 is provided in the middle between the narrow surfaces 6, on which two additional pressing surfaces 7 are glued together. While the molded body 1 according to FIG. 1 is separated out of a one-piece wood fiber slab, the molded body 1 according to FIG. 2 is separated from a two-layer fibreboard which consists of two individual wood fiber slabs glued along the adhesive surface 10. Moreover, the thickness of the insulating molded body 1 according to FIG. 2 is about 6 cm smaller than that of the insulating molded body 1 according to FIG. 1.

The insulating molding 1 according to FIG. 3 differs from the two previous embodiments in that it has two adhesive surfaces 10, on which pressing surfaces 7 are glued together. That is, it is based on a total of three individually bonded individual wood fiberboard panels. The thickness of the insulating molding 1 according to FIG. 3 in the direction of insulation 5 is 10 cm here. As a further difference from the previous embodiments, the opposing narrow surfaces 6 are provided with Stufenfalzen 11, which are formed by cutouts 12. The Stufenfalzen 11 allow a contiguous several insulating moldings 1 with partial overlap to avoid light gaps.

The embodiment of the insulating molding 1 according to FIG. 4 differs from all previous embodiments in that the surfaces 3 and 4 do not run parallel to each other, but at a wedge angle 13. That is, the thickness of the insulating molding 1 perpendicular to the surface 3 varies between the sixth and 9 cm. The direction of insulation 5, ie the shortest Connection of the surfaces 3 and 4 no longer runs exactly parallel to the narrow sides 6 and defined by the local pressing surface level 9 of the preferentialorientation- the fibers 2. Although the preferred orientation runs exactly perpendicular to the surface 3, but only transversely to the surface 4th , Whose deviation from the vertical corresponds to the wedge angle 13. The molded body 1 according to FIG. 4 is provided for the insulation of a roof with a small angle of inclination of the size of the wedge angle 13. At the downwardly facing front surface 3, a horizontal ceiling surface is formed under the roof.

Fig. 5 shows a plan view of the insulating body 1 according to FIG. 2 on its front surface 3. The now visible length 14 of the molded body 1 is 120 cm. Also visible is the adhesive surface 10 with the pressing surfaces 7 bonded to one another there. The surface 3, as typically sawed parting surface 15, has an open structure in comparison to the narrow surfaces 6.

Fig. 6 outlines how a single or multi-layer wood fiber board 16 several moldings 1 are separated out along the parting surfaces 15, wherein the wide surface 17 of the wood fiber board 16 is the pressing surface 7, which is formed during the manufacture of the wood fiber board 16. The width of the individual strips, which are cut out of the wood fiber board 16, is the thickness of the insulating molded body 1 in the insulating direction 5. The length of the strip 14 corresponds to the length of the insulating moldings. The not visible here thickness of the wood fiber board 16 is the width 8 of the insulating moldings. The wood pulp plate 16 may, as in the case of the insulating molded body 1 shown in FIG. 1 in one layer or as in the case of Dämmforaikörper of FIGS. 2 and 3 be multilayer. Ie. have individual bonded wood fiberboard.

FIG. 7 shows a horizontal cross section through a thermal insulation composite system in front of a wall 18. The thermal insulation composite system consists of parallel gaps juxtaposed insulating moldings 1, which are glued with their rear surface 4 to the wall 18. In the remaining between the insulating moldings 1 gaps 19 20 is arranged in the form of non-dimensionally stable wood fiber insulation, which is available as rolled goods. On the front surfaces 3 of the insulating moldings 1, a dense fibreboard 26 is glued, which can be wallpapered, for example, to form a Zimmerwandoberfläche.

In the thermal insulation composite system according to FIG. 8, which is also shown in a horizontal cross-sections, 21 insulating moldings 1 are arranged close to an outer wall in front of an outer wall. The insulating moldings 1 are glued with their rear surface 4 to the outer wall 21. On its front surface 3, the Dämmförmkörper 1 plastered, wherein in the plaster 22 a Putzhaltenetz 23 is arranged. The plaster 22 forms a weatherproof layer for the insulating molded body 1.

In the thermal insulation composite system according to FIG. 9, the insulating moldings 1 are arranged close together under a cover 24, to which they are glued with their rear surfaces 4. Under the moldings 1, a plasterboard 25 is adhered to the front surface 3. In the formation of this composite thermal insulation system, the insulating moldings 1 coated with a plaster Ansetzbinder can be pressed directly to the ceiling 24 and are held there immediately. The same then applies to the plasterboard 25th

In the following examples test trials for the use of the new insulating molding 1 are reported:

Example 1:

A tensile test according to DIN EN 1607 (200 mm * 200 mm edge length) of an insulating molding according to the invention gave a tensile strength of 380 kPa. The wood pulp board from which the insulating molding had been cut out had a mean apparent density of 210 kg / m ³ .

Example 2:

A tensile test according to DIN EN 1607 (200 mm * 200 mm edge length) of an insulating molding according to the invention gave a tensile strength of 180 kPa. The wood pulp board from which this insulating molding had been cut out had a density of 145 kg / m ³ .

Example 3:

Depending on an inventive insulating moldings was attached by means of commercial gypsum Ansetzbinder to a vertical concrete wall and a concrete ceiling (from below). The adhesion took place immediately on full-surface binder application. A support of the insulating molding until the curing of the binder was not required. After curing of the bond between the insulating body and the wall a four times larger in size, 12.5 mm thick plasterboard was applied as a soft bending facing shell with the same plaster Ansetzbinder directly on the insulating molding. Again, the liability was immediate, although the planking exerted by their own weight large forces in Abreißrichtung on the insulating moldings. This construction was mounted on an uncovered exterior wall. A three-month natural weathering over the winter season due to rain, ice and snow could not affect the adhesion even with total moisture penetration of the plasterboard and the underlying Dämmformkörpers. Rather, a quick drying in dry weather was observed.

Annex: Process for the production of wood pulp plates as starting material for the production of insulating moldings

The wood pulp plates from which the new insulating molded body according to the invention can be produced, should be characterized by a low average bulk density and at the same time stable bonding of the fibers. The following is an example of a method for producing such wood pulp plates is described in detail.

It is a process for the production of lightweight fibreboard having an average density of ureter 250 kg / m ³ on the basis of lignocellulosic fibers and binder, wherein the binder is applied to the fibers and thereafter formed the fibers into a fiber mat which is calibrated and subjected to a heat treatment to cure the binder. In contrast to so-called wet process while a fiber moisture content of the fibers is adjusted so that it is less than 20% when calibrating the fiber mat and during the heat treatment. Furthermore, in contrast to so-called hot air processes, the fiber mat is contacted on both sides with smoothly sealed heating surfaces for heat transfer for heat transfer. In this case, the opposing heating surfaces are spaced apart from each other to maintain a predetermined distance, and a density profile of the wood pulp plates is adjusted so that an edge overshoot of the density compared to the average density of wood pulp plates of at least 20% results.

The fiber moisture content of the fibers when calibrating the fiber mat and during the heat treatment to cure the binder can be in the range of less than 10%, as in the case of conventional so-called dry processes. Likewise, as in a classic dry process, the heat treatment of the fiber mat via smoothly closed heating surfaces, via which the heat is transferred to the curing of the binder on the fiber mat. It is important that the heating surfaces are distance-controlled and not pressure-controlled, as is the case when carrying out conventional drying processes. The very low density of the wood pulp plates produced by the present process does not allow controlled pressure control of the heating surfaces. Due to the distance control of the heating surfaces the wood pulp panels produced but still impressed a density profile, which has a marginal increase in bulk density compared to the average density of wood pulp plates of at least 20%. The edge regions of the wood pulp plates are thus compressed compared to their average density. In connection With the smoothly closed heating surfaces, which cause this compaction results in a smooth closed surface of the wood pulp boards produced. This smoothly closed surface is unusual for wood pulp boards in the density range below 250 kg / m ³ . It allows a simple and accurate surface bonding of individual wood pulp boards in the production of new insulating moldings.

It is not to be overlooked that a low density, which is already present in the fiber mat, does not exactly facilitate heat transfer to the middle of the fiber mat during the heat treatment. Therefore, in the present method, it is preferable to spray the fiber mat with water or an aqueous solution before the heat treatment. In this way, by steaming water on the heating surfaces, a jet of steam can be directed into the interior of the fiber mat, which promotes the curing of the binder there. In addition, the water softens the fibers on the surface of the fiber mat, so that can be achieved by the action of smooth heating surfaces particularly good smooth surfaces in the finished wood fiber panels.

Except for the determination of the area-related mass occupation, the fiber mat can also be calibrated by the heating surfaces controlled at a distance.

The predetermined distance of the heating surfaces, which corresponds to the thickness of the fibreboard produced, is typically 20 to 300 mm. It is amazing in the field of larger thicknesses in this area that the wood pulp plates can still be produced by a dry process.

It is particularly preferred in the method described here, when the density profile of the wood pulp plates is adjusted so that there is an edge overshoot of the density compared to the average density of the wood pulp plates of at least 60%. A stronger edge overshoot of the bulk density is the basis for the formation of a particularly strong closed surface of the finished wood pulp plates, which may for example also have a considerable pressure stability compared to the average density of wood pulp plates.

If the average gross density of the wood pulp plates is set to 150 to 250 kg / m ³ , a common synthetic resin of the wood-based material industry can be used as the binder. The usual synthetic resins of the wood-based materials industry include urea-formaldehyde, melamine-urea-formaldehyde, melamine-urea-phenol-formaldehyde, phenol-urea-formaldehyde, phenol-formaldehyde and PMDI resins.

If the average density of wood pulp plates is adjusted to 60 to 250 kg / m ³ , a foam-forming polyurethane binder can be used as binder. In this range of bulk density, the advantage of filling the cavities in the wood pulp board between the individual fibers by the polyurethane foam makes positive. The particularly light wood pulp plates in the range below 150 kg / m ³ can not be produced without the use of a foam-forming binder of usable quality.

As a foam-forming polyurethane binder, a so-called one-component system can be used, which was developed for example by the company_Bayer and is basically available. Preferably, however, an easily controllable two-component system is used, wherein the foam-forming polyurethane binder comprises a first, NCO group-containing binder component and a second at least one polyol having binder component.

It is provided in a particularly preferred embodiment of the method described here, the fibers before the Applying the binder divided into at least two lots and apply to a first of these batches only the first, the NCO-containing binder component and a second of these batches only the second, the polyol-containing binder component and the parts of the fibers until immediately before molding the Fiber mat to mix with each other. Until the parts of the fibers have been mixed, the two binder components are so completely separated from one another. Even during the mixing of the batches of the fibers, there is still no appreciable contact between the two binder components. Only when forming the fiber mat, this contact is at the contact points of the fibers. However, this contact is still not enough to trigger a polyurethane reaction alone to a significant extent. Only over very long periods of time or by the heat treatment, the relevant main part of the polyurethane reaction is triggered, which then leads to the desired binding of the fibers in the wood pulp plates. It is surprising that, in spite of the microscopically inhomogeneous distribution of the binder components in the heat treatment, the polyurethane reaction finally takes place completely. That is, there is no noticeable reaction loss due to the fact that both binder components are not present on all fibers. At the same time as the reactivity of the binder is fully concentrated on the polyurethane reaction within the fiber mat, the binder can be used in relatively small proportions based on the fibers and the desired strength of the wood pulp plates.

The mentioned first batch may in principle contain 10 to 90% and the second batch corresponding to 90 to 10% of the total fibers. But it makes sense if the first and the second part of the fibers are about the same size, d. H. For example, each contain 40 to 60% of the total fibers.

But this does not stand in the way that even a third batch of fibers prior to mixing subjected to a different treatment becomes. In particular, a third batch of the fibers may be left without binder component until mixed with the other lots. This approach is particularly interesting in the field of very low binder proportions.

The process described herein can be carried out both batchwise and continuously, which is preferred. In continuous process control, the heating surfaces are typically provided on rear-heated metal endless belts.

When the manufacture of the wood pulp panels is carried out continuously using a PUR binder having two binder components, the lots of fibers may be stored separately after application of the binder components and before their mixing. The reactivity of the binder components does not decrease even with prolonged periods of separate storage of the batches of fibers.

The heat treatment for curing the wood pulp plates can be made so that in the middle of the molding a temperature of only 50 to 100 ° C is reached. This means that in comparison to known methods very low temperatures in the middle of the molding are sufficient. Conversely, these result in a high efficiency of the energy used in the heat treatment and in short periods of time that are required for the heat treatment. The low temperature is sufficient in the new process at least for curing the binder content in the middle of the molding, if highly reactive polyurethane binders are used whose reaction is not chemically hindered to suppress a pre-reaction.

Preferably, the fibers that are processed to make the wood pulp plates are wood fibers in the form of conventional defibrator pulp. The use of recycled wood without relevant quality losses in the end produced Dämmformkörpern possible.

The binder content can be selected in the production of wood pulp plates within wide limits, which are set by the necessary strength of wood pulp plates on the one hand and the economy 'of the process face higher binder costs on the other hand. The following information refers to the use of a polyurethane binder

Typically, the binder content of the wood pulp panels is adjusted to a total of 2.5 to 5% by weight based on atro wood fibers. This results in insulating moldings, which are used in part as a pure heat insulation body and greater densities down as wall elements with high rigidity and high insulation potential.

The method for producing the wood pulp boards described herein can also be carried out so that when forming the preform from the fibers, a layer structure with different compositions and / or proportions of the binder in the individual layers is set. Thus, for example, the proportions of binder in the outer layers of the wood pulp plates can be greater than in the middle layer in order to achieve a particularly high stability of the outer layers. But there are also other layer structures for adaptation to certain requirement profiles with the new method feasible. It will be understood that portions of fibers intended for different layers of the layer structure are not intermixed prior to formation of the fiber mat, but only those fibers provided for each layer of uniform composition.

In the process variants with the polyurethane binder of two binder components, the known broad spectrum of the properties of polyurethane bonds can be exploited, in particular by varying the composition and relative proportion of the binder component comprising the polyol. It is It is also possible to use additives which act as accelerators or retarders for one or both of the binder components. Likewise, fungicidal and / or herbicidal additives can be used for the shaped body to be produced.

In the density range of 60 to 150 kg / m ³ , mechanically stable wood pulp boards are obtained by the process described here only using a foam-forming binder, ie a polyurethane binder which has at least two binder components, PMDI and polyol, or which is a one-component system , Such wood pulp boards may also be considered fiber stabilized polyurethane foam. The binder content of atro fibers is at least 5%, which is not very much in absolute terms.

From an average density of about 150 kg / m ³ less voids between the fibers are present, so that the binder content, when using a foam-forming Pölyurethanbindemittels below 5% atro fibers can be reduced. If the stabilities are not paramount, binder levels down to within 1% may be sufficient. All percentages are, as usual, weight percentages.

From average densities of about 150 to 200 kg / m ³ , it is also possible to use non-foam-forming binders, ie customary synthetic resins from the wood-based panel industry. With lower densities in this range, however, the binder content should also be selected for lower strengths above 5%, and for higher strengths 7 to 15% binder content should be used. Preference is given to mixing systems with additions of melamine and phenols instead of the relatively brittle hardening urea-formaldehyde resins. The usual considerations between the price of the binder, possible formaldehyde elimination and possible harmful residual phenols must be taken.

LIST OF REFERENCE NUMBERS

1

Insulating shaped body

2

fiber

3

front surface

4

rear surface

5

Dämmrichtung

6

narrow surface

7

pressing surface

8th

width

9

Level of preferential orientation

10

adhesive surface

11

shiplap

12

countersink

13

wedge angle

14

length

15

interface

16

Wood pulp board

17

wide area

18

wall

19

gap

20

insulating material

21

outer wall

22

plaster

23

retaining net

24

blanket

25

Plasterboard

26

Fiberboard

Claims (15)

1. Insulating shaped body, particularly insulating board, on the basis of lingo-cellulose containing fibres glued together with a binder, the insulating shaped body having an insulation direction as well as a front surface and a back surface, with which the insulating shaped body begins and ends in the insulation direction, characterized in that the fibres (2) in the insulating shaped body (1) have a priority orientation in parallel to a plane (9) running across the front surface (2) and across the back surface (4); that at least one small surface (6) of the insulating shaped body (1) which runs in parallel to the plane (9) of the priority orientation is at least partially formed by a closed pressed face (7) of a wood fibre board (16) and/or that at least one internal gluing interface (10) running in parallel to the plane (9) of the priority orientation is provided, at which the pressed faces (7) of two wood fibre boards (16) are glued together; and that each wood fibre board comprises a boundary increase of its raw density over its average raw density of at least 20 % in the area of its pressed faces.
2. Insulating shaped body according to claim 1, characterized in that the front surface (3) and/or the back surface (4) are open cut faces (15).
3. Insulating shaped body according to claim 1, characterized in that the board thickness of each wood fibre board (16) is at least 80 mm.
4. Insulating shaped body according to any of the claims 1 to 3, characterized in that the wood fibre boards (16) have a raw density of 100 to 230 kg/m³.
5. Insulating shaped body according to any of the claims 1 to 4, characterized in that the distance of the front surface (3) to the back surface (4) is 50 to 400 mm.
6. Insulating shaped body according to any of the claims 1 to 5, characterized in that the distance of the front surface (3) to the back surface (4) is constant.
7. Insulating shaped body according to any of the claims 1 to 5, characterized in that a wedge angle between the front surface (3) and the back surface (4) is smaller than 20°.
8. Insulating shaped body according to any of the claims 1 to 7, characterized in that two small faces (6) opposing each other are provided with complementary stepped rebates.
9. Insulating shaped body according to any of the claims 1 to 8, characterized in that the front surface (3) and the back surface (4) have a length (14) in the plane (9) of the priority orientation of 600 to 1,500 mm and a width (8) running perpendicular thereto of 150 to 300 mm.
10. Insulating shaped body according to any of the claims 1 to 9, characterized in that a tear-resistance between the front surface (3) and the back surface (4) is at least 100 kPa.
11. Insulating shaped body according to claim 1, characterized in that the wood fibre boards (16) are glued together over a two-dimensional interface with a dispersion binder or an alkali silicate.
12. Heat insulation system having insulating shaped bodies according to any of the claims 1 to 10, characterized in that the single insulating shaped bodies (1) are arranged side by side in direct contact, all of their front surface (3) and all of their back surface (4), respectively, coinciding with one plane.
13. Heat insulation system having insulating shaped bodies according to any of the claims 1 to 10, characterized in that the single insulating shaped bodies (1) are arranged side by side at a distance, all of their front surfaces (3) and all of their back surfaces (4), respectively, coinciding with one plane, and gaps (19) between the insulating shaped bodies (8) being filled with other insulating materials (20).
14. Heat insulation system according to claim 12 or 13, characterized in that the single insulating bodies (1) are glued to a wall (18, 21 or 24) via their back surface.
15. Heat insulation system according to claim 14, characterized in that plaster (22) or a plate-shaped covering (25, 26) is glued to the front surfaces (3) of the insulating shaped bodies (1).

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