EP3444086B1 - Multi-function panel consisting of wood and bicomponent fibres and production metho for a multi-function panel - Google Patents

Description

The invention relates to a multifunctional panel made from wood and bicomponent fibers and a method for producing the multifunctional panel.

Boards made of wood fibers and bicomponent fibers are known per se and are produced in different thicknesses and bulk densities, depending on the planned application. An example of these products is a wood fiber insulation board with a proportion of softwood fibers of 91%, a proportion of bicomponent fibers (hereinafter: bicofibre) of 5% and a proportion of fire retardants of 4%. Such an insulation board is light and has good thermal insulation properties (thermal conductivity = 0.039 W/mK). It is soft and pliable, but its strength properties are so low that they cannot be measured. An example of such a panel is the "best wood FLEX 50" thermal insulation panel, manufacturer: Holzwerk Gebr. Schneider GmbH, Eberhardzell, which has a weight of about 50 kg/m ³ . More examples show the EP 3 170 636 A2 and the DE 10 2008 039 720 A1 . A plate made of bicomponent fibers and bast fibers is also made from the US 2007/0042664 A1 famous.

It is therefore the object of the invention to provide a wood-based panel which has improved properties.

This object is achieved with a multifunction panel according to claim 1 and with a method for producing a multifunction panel according to claim 10.

The multifunctional board according to the invention consists of wood fibers and bico fibers and optionally at least one additive or a mixture of additives, wherein the proportion of wood fibers can be from 10% by weight to 90% by weight and the proportion of bico fibers can be correspondingly 90% by weight. % to 10% by weight. The at least one or the mixture of additives comprises fungicides, insecticides, algicides and hydrophobing agents. The density of the multifunctional board can be from 100 kg/m ³ to 300 kg/m ³ .

Fibers and fiber bundles that are obtained by defibrating wood chips are typically referred to as wood fibers. The smaller-sized fibers and fiber bundles, which are collectively referred to here as wood fibers, have lower restoring forces than chips. Agglomerates of fibers, preferably coarse fiber bundles of fibers that are not completely separated, are preferably used for the multifunctional plate according to the invention, the length of which is 3 mm to 18 mm. Wood fibers are preferably used, the length of which is 6 mm to 12 mm. The diameter of the agglomerates is 100 µm to 3 mm. These wood fibers can be mixed faster and more homogeneously with the Bico fibers. The coarse fibers that are used for the multifunctional panel according to the invention have higher restoring forces in comparison to the mostly completely separated, finer fibers that are used to produce medium-density or high-density fiber panels. They have therefore proven to be suitable for the production of particularly light fiberboard.

The Bico fibers are made from two different components or materials. A core of core material is surrounded by a cladding of cladding material. Layered bicofibers can also be used, but preferred are clad fibers with a fully clad core. Typical core materials are polyethylene terephthalate (PET) or polyethylene. Co- or iso-polyethylene terephthalate (co-PET or iso-PET) is preferably used as the jacket material.

The bicofiber is solid at room temperature. The jacket material advantageously has the lowest possible melting point, at least a lower melting point than the core material. The melting point of the jacket material is preferably a maximum melting point of 160°C, particularly preferably a maximum of 130°C, in particular a melting point of 90°C to 115°C. In this way, little energy is consumed in order to melt or melt the jacket of the bico fibers in order to achieve bonding of bico fibers and wood fibers.

The bico fibers are used with a length that is advantageously shorter than the length of the wood fibers. Bico fibers are preferably used with a length of 0.5 mm to 30 mm, their diameter is usually 3 to 15 den, mostly 4 to 9 den. The thinner Bico fibers are particularly easy to process into a homogeneous mixture with the wood fibers. In addition, they enable the formation of particularly fine and evenly distributed adhesive dots. According to a particularly preferred embodiment of the multifunction panel according to the invention, it has no binder.

The proportion of wood fibers is preferably 70% by weight to 40% by weight, while the proportion of bico fibers is preferably 30% by weight to 60% by weight. According to a particularly advantageous embodiment, the proportion of wood fibers is 45% by weight to 55% by weight and the proportion of bico fibers is 55% by weight to 45% by weight.

In the embodiment according to the invention, the multifunction panel according to the invention has only wood and bico fibers. Furthermore, one or more of the following additives are added to the multifunctional panel: fungicides, insecticides, algicides and hydrophobing agents. The additives can be applied to the outer surface of the multifunction plate, but preferably they are added to the fibers before drying in the blow line or to the fiber mixture before spreading into a fiber cake so that they are distributed over the cross section of the plate. It is also conceivable that some of the fibers are mixed with the additives and that this mixture is used to spread the outer layers of the multifunctional panel.

The multifunctional panel according to the invention has a weight of at least 100 kg/m ³ to a maximum of 300 kg/m ³ , preferably a weight of 150 kg/m ³ to 250 kg/m ³ . It is therefore heavier than known insulation boards that have a weight of z. B. only 50 kg / m ³ have. However, the multifunction plate according to the invention achieves significantly more. While known lightweight insulating panels have only low strength properties and are particularly not suitable for fastening means to give support, the multifunctional panel according to the invention has a compressive strength of z. B. 45 kPa to 55 kPa and a screw pull-out strength of z. 65N to 160N. These strength values are maintained with the same good thermal insulation values of 0.035 W/mK to 0.39 W/mK achieved.

The good strength properties allow the multifunction panel to be attached without additional tools, e.g. B. to screw. It is possible to use the multifunctional panel as a load-bearing element in a sandwich construction made up of several different panels. The multifunction panel according to the invention has sufficient compressive strength and rigidity to coat it, which is not possible with known, flexible thermal insulation panels. The increased strength of the multifunctional panel also allows profiles to be attached, either by processing the edges or by applying separate profiles, as well as milling or sawing the panel.

• Mischens von Holzfasern und Bicomponentenfasern sowie des Additivs oder der Mischung von Additiven, des
• Streuens eines Faserkuchens, des
• Verdichtens des Faserkuchens unter Druck, des
• Erhitzens des Faserkuchens mittels eines Luftstroms und des
• Abkühlens des Faserkuchens unter Druck.

The process for producing the multifunctional board consists of a proportion of wood fibers of 10% by weight to 90% by weight and a proportion of bicomponent fibers of 90% by weight to 10% by weight and an additive or a mixture of additives a group comprising fungicides, insecticides, algicides and hydrophobing agents and having a density of 100 kg/m ³ to 300 kg/m ³ comprises the steps of

• Mixing of wood fibers and bicomponent fibers and the additive or mixture of additives, des
• Sprinkle a fiber cake, des
• compaction of the fiber cake under pressure, des
• Heating the fiber cake by means of an air stream and the
• cooling the fiber cake under pressure.

The wood and bico fibers are preferably mixed in several successive steps in order to obtain a mixture that is as homogeneous as possible. In a simple embodiment, all of the fibers and any additives are mixed as a uniform mixture. This mixture is used to spread and compact a single-layer panel. According to an alternative embodiment, two or more mixtures are prepared, where at least one mixture, e.g. B. the top layer mixture also contains an additive in addition to the fibers. Most often, the top layer mix containing the additive is spread as the outer layer, followed by a mix with or without other additives. Finally, the cover layer mixture is scattered again.

The fiber cake that is scattered from the fiber mixture or mixtures usually has a thickness of about 25 cm to 45 cm. This fiber cake is usually compressed to about 2% to 5% of the original thickness, so that the multifunctional panel has a thickness of 5 mm to 25 mm, preferably a thickness of 10 mm to 15 mm. Compacting is preferably carried out by two circulating conveyor belts inclined towards one another, the first of which is arranged below the fiber cake and the second inclined at an angle above the fiber cake. The maximum distance between the conveyor belts is greatest adjacent to the scattering of the fiber cake and smallest adjacent to the heating. The circulating conveyor belts are sufficient to compress the fiber cake by up to 98%; a press is not required. The conveyor belts preferably have belts made of a material which is permeable to air but which is sufficiently dense that the fibers of the fiber cake are held between the conveyor belts.

The compaction is carried out according to a simple design at ambient temperature. However, the ambient temperature is not sufficient to melt the sheath of the bico fibers. Accordingly, no sticking points can form solely through compaction.

According to a preferred embodiment, the fiber cake is already heated to a temperature above ambient temperature during compression in order to soften the sheath of the bicofiber. This can be done by means for heating the ambient air placed parallel to the conveyor belts.

The compacted fiber cake then passes through a continuous furnace, with the compacted fiber cake still being held between circulating, air-permeable belts. In the continuous furnace, the fiber cake is heated by means of heated air to a temperature that melts the bicofiber jacket, typically a temperature of approx. 100 °C to 160 °C. The melting sheath of the bicofiber bonds the core of the bicofiber to the wood fiber, creating a bonded structure that has large voids of air arranged in a scaffold of fibers.

The fibers of the multifunction board, in particular the wood fibers, have restoring forces that can still lead to an undesirable deformation of the multifunction board even after the adhesive points have been formed. In order to minimize this risk, it is preferred to continue to guide the compacted, adhesive-dotted multifunction board between conveyor belts which are in direct contact with the board surface, so that the cooling takes place while the conveyor belts fix the multifunction board in place. After cooling, the adhesive dots show a holding power that is greater than the restoring force of the wood fibers, so that the dimensional stability of the multifunctional panel is guaranteed.

Cooling can be done by supplying unheated, accelerated air. However, the cooling can advantageously also be carried out with cooled and accelerated air.

The multifunction panels of the invention are not fully flexible such. B. lightweight thermal insulation boards. They are sufficiently rigid to be able to be manufactured in any dimensions. The multifunction plates according to the invention are therefore also available as large-format plates, e.g. B. with a format of 2800 mm × 2070 mm. These formats can also be produced because simple production devices are sufficient and the production takes place without complex presses.

Another advantage of the multifunction panel according to the invention is that it can be disposed of without any problems. Thermal disposal of the panel is also possible.

Fig.1

eine schematische, nicht-maßstäbliche Darstellung eines Schnitts durch eine erfindungsgemäße Multifunktionsplatte,

Fig. 2

ein nicht-maßstäblicher Ausschnitt aus einem Querschnitt der erfindungsgemäßen Multifunktionsplatte,

Fig. 3

eine schematische Darstellung der Herstellung einer Multifunktionsplatte.

Details of the invention are explained in more detail below using exemplary embodiments. Show it:

Fig.1

a schematic representation, not to scale, of a section through a multifunction panel according to the invention,

2

a detail, not to scale, of a cross section of the multifunction panel according to the invention,

3

a schematic representation of the production of a multifunction panel.

1 shows a schematic representation of a multifunction board 1, which has wood fibers 2 and bico fibers 3. The wood fibers 2 are 6 mm to 18 mm long. They consist of agglomerates of fibres, ie bundles of fibers which result from the defibration of wood chips and which, after defibration, adhere to one another or which are not yet completely separated from one another. The diameter of the agglomerates is between 100 µm and 3 mm. The bico fibers 3 are much thinner; they consist of co- or iso-PET as the jacket material and PET as the core material. Their length is up to 30 mm and their diameter is about 6 den. 1 shows the larger wood fibers 2 with a proportion of 44% by weight in the multifunction panel 1 and the much finer bico fibers 3 with a proportion of 56% by weight. The multifunctional panel 1 is 11 mm thick and has a weight of 150 kg/m ³ . The dimensions of the plate are 2800 mm x 2070 mm.

The fiber mixture of wood and bico fibers 2, 3 forms a three-dimensional framework. At the crossing points between the wood and bico fibers but also between bico fibers, as in 2 shown, adhesive points 4 are formed, which give the plate strength without reducing the soundproofing properties. The restoring force of the wood fibers 3 makes it possible to produce a multifunctional panel with a large proportion of cavities, so that the panel has a low weight. At the same time, the high proportion of bico fibers results in a very high compressive strength in relation to the low weight and, surprisingly, a high screw pull-out resistance in relation to the weight. An increasing proportion of bico fibers leads to an increase in compressive strength.

3 shows the production of the multifunction panel according to the invention. The mixture of wood and bico fibers, to which additives may also be added, is scattered from a reservoir 5 via a star feeder 6 to form a fiber cake 7 approximately 30 cm thick. The fibers are mixed beforehand in a manner known per se, preferably in several stages or steps, in order to achieve a mixture which is as homogeneous as possible.

The fiber cake 7 is scattered onto a lower conveyor belt 8 . The lower conveyor belt 8 is aligned horizontally. At an angle to this, the upper conveyor belt 9 is inclined. At the end 10 of the upper conveyor belt 9, which is adjacent to the reservoir 5, the distance to the lower conveyor belt 8 corresponds to at least the thickness of the fiber cake, here about 30 cm. The distance between the upper conveyor belt 9 and the lower conveyor belt 8 decreases to the second end 11 of the upper conveyor belt to the predetermined thickness of the multifunction panel, here 11 mm. Fans are arranged parallel to the conveyor belts 8 and 9 and cause heated air to flow through the fiber cake 7 . While the fiber cake 7 is moved from the first end 10 of the upper conveyor belt 9 to its second end 11, the fibers compress due to the decreasing distance between the upper and lower conveyor belts 8, 9 to the thickness provided for the respective multifunction panel 1. At the same time, the jacket of the Bico fibers is already preheated.

After compression, the multifunctional panel 1 is guided into a continuous furnace 14 between the lower conveyor belt 12 and a second upper conveyor belt 13 arranged parallel thereto. Heating devices 15, the z. B. generate heat via heating wires or infrared radiation are arranged above and below the conveyor belts 12 and 13. The heating devices 15 are optionally supported by fans in order to accelerate the heated air and convey it through the conveyor belts 12, 13 and the multifunction panel 1. For this purpose, the circulating belts of the conveyor belts 12, 13 are made of heat-resistant, air-permeable material, e.g. B. a metal mesh or a fabric that is dense enough to hold back the wood and bico fibers 2, 3 despite the air permeability.

In the continuous furnace 14, the jacket of the bico fibers is now further heated to such an extent that the jacket melts or softens to such an extent that wood fibers 2 or other bico fibers 3 that are in contact with the jacket form an adhesive point 4 with the melted or softened jacket (cf . 2 ). Due to the high proportion of bico fibers 3, numerous adhesive points 4 are formed, which give the multifunctional panel 1 significantly greater strength than a thermal insulation panel according to the prior art, which has only a 5% proportion of bico fibers.

The adhesive dots 4 produced in this way in the continuous oven 14 are initially still soft. At least some of them still have a low strength, so that the restoring force of the wood fibers 2 is greater than the strength of the adhesive dots 4. If the still warm multifunction panel 1 were now released from the conveyor belts 12, 13, there would be a risk of undesirable changes in shape . In order to avoid these undesired changes in shape, the height of the multifunctional plate 1 is further fixed by the conveyor belts 12 and 13 and transferred to a device 16 for cooling. The device 16 for cooling is provided with means 17 for generating cool air, which is guided through the multifunction panel. The means 17 for generating cool air can be simple fans that convey air through the multifunction panel 1 that has the ambient temperature that prevails outside the production plant. Optionally, a cooling device can also be provided, which cools the air to a specific temperature. The multifunctional board 1 is only released from being guided by the conveyor belts 12, 13 when the adhesive points 4 have solidified as a result of cooling to such an extent that their holding force is greater than the restoring force of the wood fibers 2.

The width of the multifunction plate 1 is 2800 mm. The multifunction panel 1 is produced in a continuous process in infinite length. It can be shortened to any length, e.g. B. to a length of 2070 mm.

The multifunction panel 1 described above and the manufacturing process for this multifunction panel are modified according to the invention in such a way that in addition to the wood and bico fibers 2, 3, one or more additives are also added, e.g. B. an additive or a mixture of additives from the group of additives which includes fungicides, insecticides, algicides and waterproofing agents. The additives are usually added in amounts of up to 10% by weight. They are either already added to the wood fibers in the blow line or they are added to the mixture of wood fibers 2 and bico fibers 3 altogether, or a second storage container is used, from which a separate layer of the fiber cake 7 is scattered, in which the first storage container 5 and the second storage container sprinkle the fiber cake 7 alternately. The second storage container preferably scatters the outer layers of the fiber cake 7.

In the following, some examples show different formulations for the composition and design of the multifunction panel according to the invention:

Example 1 (not according to the invention)

56% by weight of bico fibers 3 and 44% by weight of wood fibers 2 are scattered from the reservoir. First, in a first batch, a fiber cake 7 with a quantity of 1.76 kg/m ² is scattered, compacted, heated and cooled to produce a multifunctional panel 1 with a thickness of 11 mm. In a second batch, 1.98 kg/m ² fibers are scattered and in a third batch 2.75 kg/m ² fibers are scattered, in each case to produce a multifunctional panel with a thickness of 11 mm. Table 1 shows the thickness (mm), density (kg/m ³ ), compressive strength (kPa), thermal resistance (W/mK) and bolt pull-out strength (N). Table 1 batch 1 batch 2 batch 3 Density (kg/m ³ ) (DIN EN 323) ^160kg /m3 ^180kg /m3 250kg/ ^m3 Thickness in mm 11 11 11 Compressive strength (kPa) (DIN EN 826) 51 53 55 Thermal resistance λ (W/mK) (DIN EN 12667) 0.03576 0.03726 0.03872 Screw pull-out strength (N) (DIN EN 320) 95 129 160

It can be seen that the values for compressive strength and screw pull-out strength increase with increasing density, the screw pull-out strength even significantly. The thermal resistance also increases moderately.

Embodiment 2 (not according to the invention)

In a first batch, a fiber mixture of 30% by weight bico fibers 3 and 70% by weight wood fibers 2 is scattered onto the lower conveyor belt 8 in an amount of 1.98 kg/m ² . The second batch shows a fiber mixture of 44% bico fibers and 56% by weight wood fibers and the third batch has a fiber mixture of 56% by weight bico fibers 3 and 44% by weight wood fibers 2 . The second and third batches are also spread at 1.98 kg/m ² . Table 2 shows that the thickness and density of the boards are identical, only the proportion of wood fibers 2 and bico fibers 3 varies. Table 2 batch 1 batch 2 batch 3 variant V1: 30% Bico V2: 44% Bico V3: 56% Bico Density (kg/m ³ ) (DIN EN 323) 180 180 180 Thickness in mm 11 11 11 Compressive strength (kPa) (DIN EN 826) 45 49 55 Thermal resistance λ (W/mK) (DIN EN 12667) 0.03709 0.03713 0.03726 Screw pull-out strength (N) (DIN EN 320) 68 82 129

With increasing use of bico fibers, the strength properties increase significantly. The heat transfer resistance does not change with varying fiber content; it is obviously dependent on the density of the multifunction disk 1.

reference list

1

multifunction plate

2

wood fiber

3

Bico fiber (bicomponent fiber)

4

glue point

5

reservoir

6

rotary valve

7

fiber cake

8th

Lower Conveyor

9

Upper Conveyor

10

Top end

11

Lower end

12

Lower conveyor belt/continuous oven

13

Upper conveyor belt / continuous oven

14

continuous furnace

15

heating devices

16

Device for cooling

17

means of cooling

Claims (16)

1. A multi-function panel, consisting of wood fibers (2) and bicomponent fibers (3) as well as an additive or a mixture of additives, wherein the wood fibers (2) take up a proportion of 10 wt.% to 90 wt.% and the bicomponent fibers (3) take up a proportion of 90 wt.% to 10 wt.%, wherein the at least one additive or the mixture of additives comprises a group that comprises fungicides, insecticides, algicides and hydrophobing agents and wherein the multi-function panel (1) has a density of 100 kg/m³ to 300 kg/m³.
2. The multi-function panel according to claim 1, characterized in that the proportion of wood fibers (2) is up to 70 wt.%, preferably up to 60 wt.%, advantageously up to 55 wt.%, preferably up to 45 wt.%, particularly preferably up to 30 wt.%, and in that the proportion of bicomponent fibers (3) is up to 30 wt.%, preferably up to 45 wt.%, advantageously up to 55 wt.%, preferably up to 60 wt.%, particularly preferably up to 70 wt.%.
3. The multi-function panel according to claim 1 or 2, characterized in that the wood fibers (2) are used as agglomerates with a length of 3 mm to 18 mm, advantageously with a length of 6 mm to 12 mm.
4. The multi-function material according to at least one of the preceding patent claims, characterized in that the bicomponent fibers (3) comprise polyethylene terephthalate or polyethylene, in each case in isolation or in a mixture, as the core.
5. The multi-function material according to at least one of the preceding patent claims, characterized in that the bicomponent fibers (3) comprise co- or iso-polyethylene terephthalate as the sheath.
6. The multi-function material according to at least one of the preceding patent claims, characterized in that the sheath of the bicomponent fibers (3) has a lower melting point than the core, in particular the sheath has a melting point of less than 160°C.
7. The multi-function material according to at least one of the preceding patent claims, characterized in that the bicomponent fibers (3) have a length of 0.5 mm to 30 mm.
8. The multi-function material according to at least one of the preceding patent claims, characterized in that the multi-function panel (1) has a density of 160 kg/m³ to 250 kg/m³.
9. The multi-function panel according to at least one of the preceding patent claims, characterized in that the screw-holding capacity of the multi-function panel (1) is over 60 N, advantageously over 100 N, preferably over 150 N.
10. A method for producing a multi-function panel (1) consisting of a proportion of wood fibers (2) of 10 wt.% to 90 wt.% and a proportion of bicomponent fibers (3) of 90 wt.% to 10 wt.% as well as an additive or a mixture of additives from a group that comprises fungicides, insecticides, algicides and hydrophobing agents and having a density of 100 kg/m³ to 300 kg/m³, said method comprising the steps of:

    - mixing wood fibers (2) and bicomponent fibers (3) as well as the additive or mixture of additives,

    - sprinkling a fiber cake (7),

    - compressing the fiber cake (7) under pressure,

    - heating the fiber cake (7) by means of an airflow,

    - cooling the fiber cake (7) under pressure.
11. The method according to claim 10, characterized in that the mixing is done in multiple stages.
12. The method according to claim 10 or 11, characterized in that the compression is done by conveying the fiber cake (7) between two conveyor belts (8, 9) arranged in a wedge shape.
13. The method according to at least one of claims 10 to 12, characterized in that the conveyor belts (8, 9, 12, 13) comprise an air-permeable conveyor belt.
14. The method according to at least one of claims 10 to 13, characterized in that the heating is done at least in part as early as during the compression.
15. The method according to at least one of claims 10 to 14, characterized in that the heating is done in a conveyor oven (14).
16. The method according to at least one of claims 10 to 15, characterized in that the cooling is done by feeding in accelerated air and/or by feeding in cooled air.

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