EP3383605B1 - Fibreboard with increased resistance to fungal attack and method for producing the same - Google Patents

Description

The invention relates to a method for producing a fiberboard having increased resistance to fungal attack and a fiberboard obtainable by this method. Another object of the invention is a roof or wall component, which consists of such a fiberboard or contains. The invention further relates to the use of certain inorganic Bronsted acids in fiberboard manufacture to increase the resistance of the fiberboard to fungal attack, and to the use of certain inorganic Bronsted acids in the surface treatment of a fibrous mat in fiberboard manufacture for hydrophobing and / or increasing the resistance of the fiberboard fungus.

Fiberboard is widely used in interior and loft conversions as well as in furniture construction, for example as a wall element for exterior or interior use, as a support plate for laminate flooring, for front and rear fronts of furniture or for Unterbeplankung and insulation of roof structures. Different types of fiberboard are known to those skilled in the art. These are for example in the " Taschenbuch der Holztechnik "by A. Wagenführ and F. Scholz, Hanser Verlag, 2012, on pages 146 to 149 described. If here or elsewhere "plate" is mentioned, then it is meant a cuboid flat product, which is defined by 6 surfaces: four edge surfaces and a top and bottom, the top and bottom here together and in contrast to the Edge surfaces are referred to as "main pages" or "surfaces of the disk".

In the construction sector, DHF boards (vapor-permeable and moisture-resistant fiberboards) are preferably used as undercover boards for roofing roofs and walls used. Here a good moisture resistance or a good protection against microbial infestation is desired because DHF plates may be exposed to water or moisture for long periods of time. For example, this burden may result from external weather conditions or from evaporating water in interiors, especially in new buildings. So in new buildings after plastering the walls still residual moisture is present, which evaporates over time and rises towards the roof. Here, in practice, moisture condenses on the DHF boards installed in the roof truss, and mold can form within a short time, especially on the inwardly directed surface of the DHF board. This problem also occurs with insufficiently sealed or damaged roofs (which may also affect the outward facing surfaces of the DHF board) as well as unventilated, cold attics.

An increased risk of mold growth can also occur in fiberboard, which have been installed in walls in the interior and exterior and as rear fronts of furniture, which are directed to an outer wall. Therefore, it is desirable to provide improved wood fiberboards, particularly DHF sheets, in which at least one of the two major sides of the fiberboard has increased resistance to fungal attack.

Apart from the main sides, an increase in fungal resistance may be desirable also in the edge surfaces of the fiberboard. However, this aspect tends to take a back seat because the edges usually have a much smaller surface area compared to the major sides of the fiberboard. In addition, when laying the edges of the fiberboard are typically in contact with each other, whereby the edges are not directly exposed to moisture.

To avoid mold formation in fiberboard, the use of various substances having a biocidal or fungicidal action is known from the prior art. The usual wood preservatives, the infestation by wood-destroying and -verfärbende Preventing fungi or insects (preventive wood protection) or, in the case of an already occurring infestation, killing harmful organisms (combating wood protection) are generally always to contain biocides as active constituents. Biocides are classified in Biocide Regulation (EU) No 528/2012.

Examples of commonly used biocide wood preservatives are coal tar oils (creosols), water-soluble / water-based preservatives (borates) or solvent-containing preservatives (triazoles). Although the tar oils have a good antimicrobial efficacy. However, it should be remembered that these are harmful to health, have a strong odor and are poorly paintable and glued. The water-soluble protective agents are in many cases combinations of inorganic salts with mostly water-insoluble organic active ingredients. The latter are rendered water-emulsifiable / dispersible and thus water-dilutable with the aid of emulsifiers or dispersants (therefore "water-based"). Water-based or water-soluble wood preservatives are inter alia in the EP 2 146-571 B1 and EP 1813 402 A2 described.

EP 0 267 516 A2 relates to a process for the production of wood-based panels, in which wood-based material particles are glued with a hardener-free binder, then scattered to a nonwoven and then pressed. During the compaction phase, an acidic or basic hardener in gaseous phase or in a binary phase with a gaseous carrier is supplied in the press via the surfaces of the nonwoven and / or directly into the interior of the nonwoven. EP 0 267 516 A2 discloses the following features of claim 1: providing a fiber mat containing glued wood material particles, contacting the fiber mat with a Bronsted acid, wherein the Bronsted acid can be phosphoric acid, and compressing the fiber mat treated with the Bronsted acid. The EP 0 267 516 A2 does not disclose that the acid is applied to at least one surface of one of the two major sides of the fiber mat such that the core of the fiberboard remains acid-free.

The EP 2 146 571 B1 describes a furniture and / or interior fitting, which is treated by impregnation with a resin composition antimicrobial. The resin composition contains a biocidal composition
from an organic biocidal compound (isothiazolinone) and a nanoscale metal oxide (ZnO, MgO or Al ₂ O ₃ ). A disadvantage of such a combination, however, is that emulsifiers are added as solubilizers, which can additionally promote the swelling of the fiber board by their emulsifying effect.

Usta et al. (2009), Int.]. Mol. Sci. 10. 2789-2797 describes the effects of various boron compounds on the termite resistance of MDF boards. The urea-formaldehyde resin was either borax. Boric acid. Zinc borate or sodium perborate tetrahydrate added. Usta et al. discloses the following feature of claim 1: contacting wood fibers with a Brönsted acid. For the further independent claims Usta el al. the following feature: Use of a Bronsted acid to increase the resistance of a fibreboard to fungal attack. Usta et al. does not disclose the use of the particular Brönsted acids recited in claim 1 or the wholly or partially contacting at least one surface of either of the two major sides of the fiber mat with the particular Brönsted acids of claim 1 such that the core of the fiberboard remains acid-free.

The EP 1 813 402 A2 describes a fiberboard for roofing and wall construction, which contains borates as mold fungus protection in their top layer. The boron compounds appear to be effective against fungi in principle, but these compounds are water-soluble and not fixed in the fiber material. As a result, they remain easily washable even with the addition of fixing agents and their effect is lost in the course of the application period.

Due to the disadvantages described above, many wood preservatives containing biocidal substances, therefore, can not be used optimally in the roof or interior. Furthermore, the biocides may be due to their potential Emission through evaporation, attrition, or other release may affect human health. In principle, biocides pose the risk of resistance and allergisation, so their exposure should be avoided as much as possible. Often biocides also lose their effect through gradual (natural) degradation. For example, the water-soluble or water-based wood preservatives can be washed out of the fiberboard over time, which on the one hand reduces the antimicrobial effectiveness and, on the other hand, increases the environmental impact.

Based on the above-described prior art and its disadvantages, an object of the invention to be able to produce a fiberboard with increased resistance to fungus without having to use an unstable, washable or risky substance. Another aspect of the object underlying the invention was to produce an environmentally friendly product, which is characterized by a long-lasting fungus resistance.

Furthermore, it was a further object of the invention to provide a fiberboard and a method for its production, by the sufficient protection against fungal attack with little effort, in particular by low entry of foreign substances in the fiberboard and less to no increase in the cost of production the fiberboard is reached.

This object is achieved by the method according to claim 1, the fiberboard according to claim 12, the roof or wall component according to claim 134 and a use according to claim 14 or 15. Particular embodiments of the invention are given in the dependent claims.

1. a) Bereitstellen einer Fasermatte enthaltend beleimte, lignocellulosehaltige Fasern,
2. b) Gänzliches oder teilweises In-Kontakt-Bringen mindestens einer Oberfläche einer der beiden Hauptseiten der Fasermatte aus Schritt a) mit einer anorganischen Brönsted-Säure, wobei die anorganische Brönsted-Säure ausgewählt ist aus der Gruppe, bestehend aus Phosphorsäure, phosphoriger Säure, unterphosphoriger Säure. Phosphonsäure und deren Mischungen.
3. c) Verpressen der aus Schritt b) erhaltenen, oberflächenbehandelten Fasermatte zu einer Faserplatte, deren Kern säurefrei bleibt.

The invention according to claim 1 is a process for producing a fiberboard, comprising the steps:

1. a) providing a fiber mat containing glued, lignocellulose-containing fibers,
2. b) Wholly or partially contacting at least one surface of one of the two major sides of the fiber mat of step a) with an inorganic Brönsted acid, wherein the inorganic Bronsted acid is selected from the group consisting of phosphoric acid, phosphorous acid, hypophosphorous Acid. Phosphonic acid and mixtures thereof.
3. c) pressing the surface-treated fiber mat obtained from step b) into a fiberboard whose core remains acid-free.

The method according to claim 1 is based on known from the prior art process for wood fiber board production, wherein the usual process steps an additional surface treatment of the fiber mat with one of said inorganic Brönsted acids is carried out prior to compression into a fiberboard. Bronsted acids are well known to those skilled in the art. Examples and properties of Bronsted acids are, for example, in " Basic Knowledge of Chemistry ", C. Mortimer, Thieme, 7th edition, 2001 on pages 281 to 290 described.

In contrast to the substances or biocides known from the prior art, the inorganic Bronsted acids used according to claim 1 are neither biocides within the meaning of the biocide regulation nor do they entail the above-described harmful or environmentally harmful disadvantages. Since the inorganic Bronsted acids used according to claim 1 do not have the health-endangering properties of conventional biocides or wood preservatives and can also be used in low concentrations, an environmentally friendly, "green" product can be obtained by the process according to claim 1. Since it is under the heat of the pressing in step c) of the process According to claim 1 probably comes to a Abreagieren the inorganic Brönsted acid used, the disadvantages occurring in the prior art of leaching or inactivation of the biocide are avoided.

Surprisingly, it has been found that by using the inorganic Brönsted acids mentioned in claim 1, the abovementioned problems known from the prior art can be largely avoided or reduced. Practical experiments have shown that surface treatment of the fiber mat with these inorganic Bronsted acids can provide fiberboards which have increased resistance to fungal attack. This was surprising because the inorganic Brönsted acid itself does not act as a chemical biocide.

If here or elsewhere "mushroom" or "fungal attack" is mentioned, then "mushroom" means the broad definition of the realm of "fungi" from biological taxonomy. In addition to unicellulars such as baker's yeast, this also includes multicellulars such as molds or mushrooms. By "fungus" are meant above all also wood-destroying and / or holzverfärbende mushrooms or the infestation by these. These wood-destroying and / or wood-discolouring fungi typically damage the wood by, for example, brown rot, white rot, soft rot, mold, blue streaks or red streaks. In one embodiment, the fungi are molds and / or blue fungi. The fungi may also be selected from the Basomycetes, Ascomycetes and Deutomycetes. By "increase in resistance" as used herein is meant a reduction in fungal infestation compared to a non-biocidal, fungicidal and / or fungiostatic reference. This resistance of the fiberboard to fungal attack can be determined, for example, in accordance with the standard EN ISO 846: 1997 "Determination of the action of microorganisms on plastics" as described in the working examples.

The method according to claim 1 proved in practical experiments also to be particularly gentle on the wood fibers. In the fiberboards obtained by this method, the required mechanical properties were maintained despite the acid treatment. This was surprising, since the skilled person would normally expect fiber damage and thus impairment of the mechanical properties of the end product in the case of acid treatment.

In principle, it would also be conceivable to use the fibers prior to providing the fiber mat, e.g. to be treated with the inorganic Bronsted acid already during defibration, in the digester or in the refiner. In this case, however, the treated fibers would have to undergo an additional thermal step. This can lead to damage to the fiber structure. In contrast, the process according to claim 1, the treatment of the fibers only after their gluing in the stage of the fiber mat, i. in step b). Since, by this procedure, the treated fibers are subjected to only one thermal step, namely compression to a fiberboard, the process according to claim 1 is particularly gentle on the fibers.

In addition, only the surface or the cover layers of the fiber mat are treated with the inorganic Bronsted acid, the core of the fiberboard remains acid-free. On the one hand, this has the advantage that the fibers of the plate core are not treated with the inorganic acid, thereby avoiding possible fiber structure damage and leaving the mechanical properties, which are essentially determined by the plate core, as far as possible unimpaired. Another advantage is that the method according to claim 1 thereby also for a variety of fiber-binder combinations is suitable. Because acid can affect the properties of the binder and thus lead to insufficient binder effect and / or mechanical properties of the final product, even if the core of the fiber mat has been treated with acid.

Practical experiments have shown that a treatment of the surface or the cover layer of the fiber mat shortly before press entry is already sufficient for the inventively achieved increased resistance to fungi. Since only one surface treatment takes place, in the process according to claim 1 even low concentrations of the inorganic Brönsted acids mentioned there, based on the total weight of the fiber mat, are sufficient to ensure increased resistance to fungi.

Without wishing to be bound by any particular scientific theory, the surprising effect of the treatment with the inorganic Brönsted acids mentioned in claim 1 could probably be explained by the fact that hydroxyl groups, in particular of polysaccharides or other cell wall polymers contained in the fibers and provide a food source for fungi and other microorganisms, modified so that they can no longer serve as a source of food for the fungi. As a result, the fungi are probably no longer able to replicate and / or damage the fibers through their metabolic products.

Further, it has been found that the fiberboards obtained by the process according to claim 1 are more hydrophobic than comparably produced fiberboards, in the manufacture of which the fibrous mat has not been surface-treated with an inorganic Bronsted acid. This is particularly advantageous for fiberboards which are exposed to increased moisture, as this can reduce unwanted swelling of the fiberboard. Further, it has been found that this hydrophobing effect acts synergistically with the antifungal effect of treatment with the inorganic Brönsted acid.

Without wishing to be bound by any particular scientific theory, the increased hydrophobicity of the surface of the fiberboard is presumably due to elimination of the free-standing hydroxyl groups of the polysaccharides or others due to treatment with the inorganic Bronsted acid Cell wall polymers contained in the fibers. This results in less interaction with the water molecules and results in a hydrophobization of the fiberboard surface.

Moreover, the fiberboards produced by the method according to claim 1 surprisingly show a much smoother surface than comparably produced fiberboards. It has been found that superficial water mainly bubbles off and does not penetrate into the treated surface. Due to the above-described nutrient source reduction and the chemical hydrophobing by elimination of the free-standing hydroxyl groups ("chemical hydrophobing"), a physically densified surface ("physical hydrophobing") indeed synergistically results which further increases fungal resistance by preventing moisture penetration.

Another advantage of the treatment with the inorganic Brönsted acids mentioned in claim 1 is that their use can be easily integrated in conventional processes of the wood industry for the production of fiberboard. The water solubility of the inorganic Bronsted acids used in the process according to claim 1 is of particular advantage. - Aqueous solutions or suspensions can be well integrated into the usual process steps and equipment used in fiber board production. There are no time-consuming intermediate steps or process interruptions required. The inorganic Brönsted acid can be applied for example via a blowline. Due to the water solubility of the inorganic Brönsted acid, no organic solvents need to be introduced, which on the one hand represent a fire hazard and on the other hand represent an additional, potentially harmful source of emissions.

Moreover, despite the water solubility of the inorganic Bronsted acids, the known problems of common water-soluble wood preservatives can be avoided. It could be made in the fiberboard by the process according to claim 1 no harmful or environmentally harmful residues or emissions are detected. In addition, it has been found in practical experiments that the fungal resistance is maintained over time, so there is no stability or Auswaschproblematik. This is presumably based on the covalent linkage which the inorganic Bronsted acid undergoes during the reaction in the pressing step with the fiber material and / or the binder. In the finished fiberboard, the inorganic Brönsted acid does not appear to be chemically active nor does it constitute a biocide. Rather, the fungicidal effect of the invention is based on a type of "physical" action of the surface treated with the inorganic Bronsted acid and thereby modified.

Another advantage over the conventional water-based, non-reactive wood preservatives is that no further additives, such as emulsifiers, are required to dissolve the inorganic Bronsted acid and apply it to the fiber mat can. As a result, an additional swelling of the fiber board can be avoided.

In addition, many inorganic Bronsted acids are available inexpensively.

The method according to claim 1 is particularly well suited for the production of fiberboard and is not limited to any specific fiber plate type. The fiberboards obtainable by the process may be single-layered or multi-layered.

The method according to claim 1 has proven to be particularly practical for the production of diffusion-open fiberboard for roof and wall construction (hereinafter called "DHF plates"). In particular, the embodiments described herein allow the uncomplicated increase in fungal resistance of at least one major side of the DHF plate. Especially advantageous to this is that it is possible to obtain such a DHF plate with increased resistance to fungal attack without expensive intermediate steps or further chemical aftertreatment. Surprisingly, the DHF plate obtainable according to the invention (see claim 13) appears to have increased hydrophobic properties and a smoother surface. This provides additional protection against ingress of water or moisture.

Furthermore, it has been found that the major side of the fiberboard treated with the Bronsted inorganic acid has a darker coloration than the remaining areas of the fiberboard which were not treated. The discoloration is probably due to the treatment or reaction of the inorganic Brönsted acid with the lignocellulosic material. Although discolorations of the wood material or the final product are usually not desired by the skilled person, this is particularly advantageous in the method according to claim 1, since so the successful treatment and / or the uniformity of the surface treatment on the surface of one of the main sides, in cross-section or on the Edge surfaces of the fiberboard can be read.

The darker color of the treated surface is also of particular advantage in fiberboards, especially DHF sheets, which have only one major side treated, ie only one major side with increased resistance to fungal attack, because of this darker coloration the treated major side is untreated Main page can be distinguished. Thus, a likelihood of confusion between the treated and untreated main page can be largely avoided. Furthermore, this also no further markers indicating the difference between the treated and the untreated main page must be applied to the fiberboard, in particular the DHF plate, and the expert knows in which orientation (eg, treated side inside) he the fiberboard must obstruct. Overall, not only can the likelihood of confusion be reduced, but also additional process steps and thus costs can be avoided.

In principle, various methods for the production of fiberboard, in particular DHF, HDF or MDF boards, are known to the person skilled in the art. Due to the advantages described above, the treatment with the inorganic Bronsted acid can be easily integrated in a variety of production processes, such as in a conventional process for producing DHF, HDF or MDF boards. The production of fibreboards by the dry or wet process and other processes is described, for example, in Wood Materials and Glues "by M. Dunky and P. Niemz, Springer Verlag, 2002 pages 149 to 152 described. A description of the characteristics of the different types of fiberboard, process steps for the production of these and the equipment and materials needed for them are also available in the " Taschenbuch der Holztechnik "by A. Wagenführ and F. Scholz, Hanser Verlag, 2012, on pages 225 to 245 described.

The usual methods for producing a single-layer or multi-layer fiberboard have the following steps in common: First, the wood material is treated in a digester and then defibered. The comminution or defibration of the wood material is often done in a refiner. Typical process conditions used in industry for comminution or defibration are process temperatures of 160 to 200 ° C and pressures up to 10 bar. Thereafter, the fibers are optionally dried and then glued. The gluing of the fibers can be done in a Beleimtrommel by spraying. In the production of fiberboard a variety of binders can be used. Usually, no hardeners are added to the binder in fiberboard manufacture. The glued fibers are finally scattered into a fiber mat, which the person skilled in the art also calls "fiber cake", optionally preformed and pressed into a fiberboard.

According to the methods known from the prior art, the method according to claim 1 initially provides that in step a) a fiber mat containing glued, lignocellulosic fiber is provided.

The provision is made in conventional processes for making fiberboard, e.g. by spreading lignocellulosic, glued fibers into a fiber mat. Typically, the fibers are first glued and then sprinkled onto a forming belt to form a fiber mat. The fiber mat can be additionally formed in a further step and / or smoothed on its upwardly facing surface. Preferably, the fiber mat or the fiberboard consists essentially of lignocellulose-containing fibers. In the "essential" here means up to 80, 85, 90, 95, 98 or 99 wt .-%, based on the total weight of the fiber mat or the fiberboard. In this case, the fiber mat or the fiber board further additives, such as fire retardants, solvents, solubilizers, viscosity adjusting agents, wetting agents, emulsifiers, pH-adjusting agents, fats, fatty acids or stabilizers containing.

If here or elsewhere the term "lignocellulosic fibers" is used, it means any type of fiber containing lignocellulose. Lignocellulose according to the invention contains lignin as well as cellulose and / or hemicellulose. "Cellulose" is an unbranched polysaccharide consisting of several hundred to ten thousand cellobiose units. These cellobiose units, in turn, consist of two molecules of glucose linked by a β-1,4-glucosidic bond. "Hemicellulose" is a collective name for various components of plant cell walls. The hemicelluloses are branched polysaccharides with a lower chain length - usually less than 500 sugar units - which are composed of different sugar monomers. Hemicellulose is composed essentially of various sugar monomers such as glucose, xylose, arabinose, galactose and mannose, which sugars may have acetyl and methyl substituted groups. They have a random, amorphous structure and are readily hydrolyzable. Xylose and arabinose consist for the most part of sugar monomers with five carbon atoms (pentoses). Mannose or galactose consist mainly of sugar monomers with six carbon atoms (hexoses). "Lignins" are amorphous, irregularly branched aromatic macromolecules, which occur in nature as part of cell walls and there cause the lignification (lignification) of the cell. They are composed of substituted phenylpropanol units, have a lipophilic character and are insoluble in room temperature in neutral solvents such as water. Precursors of lignin are, for example, p-coumaryl alcohol, coniferyl alcohol and sinapyl alcohol. The molecular weights of lignin are usually between 10,000 and 20,000 g / mol.

The lignocellulosic fibers are preferably wood fibers. These wood fibers can be produced by defibering of wood particles, wood fibers, wood chips or finely divided wood material. Preferred species of wood for the production of a fiberboard obtainable by the process according to claim 1 are, for example, softwoods, in particular pine and / or spruce wood.

Typically, the lignocellulosic fibers are glued with a binder before, during and / or after they are scattered into a fiber mat. When referring to "gluing", it may be understood as meaning wholly or partially wetting with a composition containing a binder. Such compositions are also referred to by the person skilled in the art as a "sizing liquor". Gluing can in particular also mean the uniform distribution of the binder-containing composition on the lignocellulose-containing fibers. The application of the binder-containing composition can be carried out, for example, by impregnation or spraying, in particular in a blowline. In addition to the added binders and hydrophobizing agents, surface-modifying agents which neutralize the surface and / or encapsulate the fiber can optionally also be sprayed on in the blowline. The gluing of the lignocellulose-containing fibers can also be done in a drum or by spraying on the conveyor belt.

The amount of the binder used in the gluing or gluing is preferably 0.1 to 20 wt .-%, in particular 1.0 to 16 wt .-%, more preferably 2.0 to 14.0 wt .-% or 2.0 to 10.0 wt .-%, based on the wood dry weight (solid resin / atro). For many applications, it is particularly practical if the binder in an amount of 0.1 to 15 wt .-% based on the dry weight of wood (solid resin / atro) is used. The application of the binder can be carried out, for example, in the blowline known to the person skilled in the art.

Basically, the method according to claim 1 is suitable for a variety of binder-wood fiber combinations. Examples of binders which can be used are aminoplasts, phenoplasts, vinyl acetates, isocyanates, epoxy resins and / or acrylic resins, in particular urea-formaldehyde resin (UF), melamine-formaldehyde resin, phenol-formaldehyde resin (PF), polyvinyl acetate and / or white glue ,

According to a preferred embodiment, the binder used for the gluing is a system based on urea-formaldehyde resins (UF), melamine-reinforced urea-formaldehyde resins (MUF), melamine-urea-phenol-formaldehyde resins (MUPF), phenolic resins. Formaldehyde resins (PF), polymeric diisocyanates (PMDI) and / or isocyanates used. Preferably, the binder is an isocyanate-based binder. More preferably, the binder contains an isocyanate or consists of 80, 90, 95, 99 or 100 wt .-% thereof. Particularly good results are obtained when the isocyanate is a polyisocyanate, in particular polymeric diisocyanate (PMDI).

The process according to claim 1 provides that in step b) at least one of the two surfaces of the fiber mat from step a) is treated with an inorganic Bronsted acid, the inorganic Bronsted acid being selected from the group consisting of phosphoric acid, phosphorous Acid, hypophosphorous acid. Phosphonic acid and mixtures thereof.

If the "surface of the fiber mat" is mentioned here or elsewhere, then the surface of one of the two main sides of the fiber mat or of the later main sides of the fibreboard is defined as defined above. These surfaces are to be distinguished from the edge surfaces of the fiber mat. According to one embodiment, "surface of the fiber mat" as used herein means the so-called "cover layer" of the fiber mat or fiberboard. The cover layer is the most superficial fiber layer of the fiberboard. In another embodiment, by "surface of the fiber mat" is meant the entire surface layer treated with the inorganic Bronsted acid. The thickness of this treated surface layer is dependent on the penetration depth of the inorganic Brönsted acid. The treated surface layer is to be separated from the middle layer which forms the core of the fiberboard and which does not come into contact with the inorganic Brönsted acid. Typically, the thickness of the treated surface layer (and thus also the penetration depth of the inorganic Brönsted acid into the fiber mat) is about 0.01 to 6 mm, preferably 0.01 to 4 mm, and most preferably up to 3 mm.

According to one embodiment, only one of the two surfaces of the fiber mat is treated. This is preferably the top of the fiber mat. This is to be distinguished from the underside on which the fiber mat rests.

According to another embodiment, only the underside of the fiber mat or both surfaces (i.e., top and bottom) of the fiber mat are treated.

When referring to "treating", "treating" or "treating with the inorganic Brönsted acid" herein or elsewhere, it is wholly or partially contacting at least one of the surfaces of the fiber mat with an inorganic brønsted Meaning acid. The acid can be sprinkled as a solid or as part of a solid composition. Preferably, however, the acid is used in liquid form, either in concentrated form or as pure acid or as part of a liquid containing the inorganic Brönsted acid.

"Liquid" as used herein can mean a dilute Bronsted-acid inorganic solution (i.e., the liquid then comprises the Bronsted inorganic acid as well as a diluent). On the other hand, "liquid" as used herein may also generally mean a liquid composition containing the -inorganic Bronsted acid, and optionally other components.

The contacting in step b) with the inorganic Brönsted acid or the liquid containing the inorganic Brönsted acid can be carried out, for example, by brushing or spraying. Preferably, the treatment is by spraying, e.g. by means of a blowline. Furthermore, the treatment can be carried out such that only the inorganic Brönsted acid from step b) presented and then the fiber mat from step a) provided and applied thereto. The presentation may e.g. done by spraying. However, it is also possible for the fiber mat from step a) to be provided first and then at least one of the two surfaces to be treated with the inorganic Bronsted acid from step b).

In one embodiment, the exposure time of the inorganic Bronsted acid, i. H. the time that elapses between step b) and c) (eg, time between the initiation of the spraying of the inorganic Bronsted acid to the contacting of the treated fiber mat with the press), 1 to 40 seconds, preferably 2 to 30 seconds and more preferably 2 to 20 seconds.

It has been found that the treatment of at least one of the surfaces of the fiber mat in a simple and cost-effective manner can be integrated into already common manufacturing processes for fiber board production. The provision of the fiber mat can be done by sprinkling glued fibers on a forming belt. Usually, one of the two surfaces of the fiber mat lies here the forming belt (referred to herein as the "bottom") while the other of the two surfaces of the fiber mat is facing up. The treatment with the inorganic Bronsted acid from step b) can be carried out on the top side and / or on the bottom side resting on the forming belt.

In one embodiment of the invention, first the fiber mat is provided on a forming belt and then the upwardly facing surface of the fiber mat is treated with the inorganic Bronsted acid from step b). Preferably, the inorganic Brönsted acid or the liquid containing it is sprayed on.

In another embodiment, first the inorganic Brönsted acid or the liquid containing it is placed on the forming belt and then the fiber mat is provided. The presentation of the inorganic Brönsted acid or the liquid containing it is preferably carried out by spraying. In a particular embodiment, the upwardly facing surface is additionally treated with the inorganic Bronsted acid or the liquid containing it. Thereby, a fiber mat which has been treated on both surfaces can be obtained.

In another embodiment, preferably in a continuous process for making fiberboard, both surfaces of the fibrous mat are treated with the Bronsted inorganic acid, the bottom being treated first. -Here, the treatment of the bottom can be done 1 to 40 seconds, preferably 2 to 30 seconds and especially 2 to 20 before the treatment of the top of the fiber mat.

The treatment is advantageously carried out during or after the usual fiber mat spreading and / or fiber mat forming. The treatment preferably takes place after the fiber mat formation and / or shortly before the pressing of the fiber mat into a fiber board.

The exposure time or the time between the treatment with the inorganic Bronsted acid in step b) and the compression in step c) can in principle be varied. In one embodiment, the time between the treatment with the inorganic Bronsted acid in step b) and the compression in step c) is at least 1, 2, 5, 10 or 15 seconds. The upper limit for the time between treatment with the inorganic Brönsted acid in step b) and the compression in step c) may be 5 minutes, 2 minutes, 40 seconds, 30 seconds or 20 seconds, said lower and upper limits being related to each other can be combined. Preferably, the time between treatment with the inorganic Brönsted acid in step b) and compression in step c) is 1 to 40 seconds, more preferably 2 to 30 seconds and most preferably 2 to 20 seconds.

For surface treatment, in step b) of the process according to claim 1, an inorganic Brönsted acid is used, wherein the inorganic Bronsted acid is selected from the group consisting of phosphoric acid, phosphorous acid, hypophosphorous acid. Phosphonic acid and mixtures thereof. The inorganic Bronsted acid is preferably present as (possibly diluted) liquid. Preferably, the inorganic Bronsted acid is present in the liquid in a concentration of up to 40, 50, 60, 70, 75, 80, 85, 90, 95, 98 or 99% by weight, based on the total weight of the liquid. Particularly preferred as the treatment liquid in step b) is an aqueous solution of the inorganic Brönsted acid. The liquid may also contain other additives, for example release agents.

Preferably, the inorganic Bronsted acid in step b) of the process according to claim 1 as part of a liquid composition and / or in a liquid in a concentration of 20 to 85 wt .-%, particularly preferably from 30 to 70 wt .-% and particularly preferably used from 40 to 55 wt .-%, based on the total weight of the liquid.

In particular, the liquid is an aqueous solution of the inorganic Brönsted acid, which may also contain other additives. The concentrations of inorganic Brönsted acid in "% by weight" or "% by weight" given here are understood to mean the proportion by mass. That is, it means the mass of the inorganic Brönsted acid relative to the total mass of the liquid.

The inorganic Brönsted acid to be used according to claim 1 preferably has a pK ₅ value of less than 4, and more preferably less than 3.5, 3, 2.75, 2.5, 2.3 or 2. The pK _s is the negative decadic logarithm of the acid constant K _S at standard conditions. The smaller the p K _S value is, the stronger the acid. If an acid has several dissociation stages (eg H ₂ SO ₄ : pKs 1st stage: -3, 2nd stage: 1.92), then here with the p K _S value, the p K _S value of the 1 Dissociation level meant. -PK _S Values of some important inorganic Brönsted acids can be found in the following table or, for example, in Gerhart Jander, Karl Friedrich Jahr, Gerhard Schulze, Jürgen Simon (ed.): Maßanalyse. Theory and practice of titrations with chemical and physical indications. 16th edition. Walter de Gruyter, Berlin et al. 2003, ISBN 3-11-017098-1, p. 81. Acidity strength pKS acid very strong -10 HClO ₄ -10 HI -8.9 HBr -6 HCl -3 H ₂ SO ₄ -1.32 ENT ₃ strongly 0 H ₃ O + 1.92 HSO ₄ - 2.13 H ₃ PO ₄ 3.14 HF

The inorganic Bronsted acid can be used alone or in combination with one of its salts, esters or adducts.

The preferred amount of the inorganic Bronsted acid which is applied in step b) is 3 to 150 g / m ² , more preferably 15 to 100 g / m ² and particularly preferably 25 to 75 g / m ² , based on the in step b) treated surface of the fiber mat. Treated surface means, for example, the entire surface of the top, even if parts of it are recessed, but not the sum of all surfaces of the fiber mat, ie the top, the bottom and the edge surfaces. In one embodiment, the inorganic Bronsted acid is distributed uniformly over the surface of the upper side and / or the lower side. When using dilute acid, the above g / m ² data refer to g pure acid per m ² treated surface. If, for example, 50 g of a 50% strength by weight acid solution are sprayed onto 1 m ² surface in step b), the amount of acid used here is 25 g / m ² .

The inorganic Bronsted acid is selected from the group consisting of phosphoric acid, phosphorous acid, hypophosphorous acid, phosphonic acid or mixtures thereof. Particular preference is given to using phosphoric acid, in particular ortho- phosphoric acid. It is also possible to treat it with a mixture of phosphoric acid and a salt of phosphoric acid. The salts may, for example, be alkali salts, alkaline earth salts and / or ammonium salts.

According to the invention, phosphoric acid, phosphorous acid, hypophosphorous acid, phosphonic acid or mixtures thereof are used as the inorganic Brönsted acid according to claim 1. Practical experiments have shown that this can reduce the risk of strongly acidic reactions with the lignocellulose-containing material and the concomitant reduction in quality of the lignocellulose-containing fiber or of the end product.

Particularly good results can be achieved if the surface treatment of the fiber mat with phosphoric acid or derivatives of phosphoric acid takes place. The good mode of action of the phosphoric acid was surprising since the phosphoric acid is normally attributed no biocidal, fungicidal and / or fungistatic properties. Another advantage of using phosphoric acid or one of its derivatives is that the phosphoric acid is less corrosive, so that the process equipment is less stressed.

Phosphoric acids in the context of this invention are those which have a free HO-P group. Examples of phosphoric acids which can be used according to the invention are orthophosphoric acid, phosphonic acid and / or phosphinic acid. As phosphoric acid is especially ortho- phosphoric acid into consideration. When it is mentioned here of salts of ortho- phosphoric acid, in particular phosphates, hydrogen phosphates and / or dihydrogen phosphates are meant. The salts of phosphoric acid may be, for example, their alkali metal salts, alkaline earth metal salts and / or ammonium salts or compounds. Salts of phosphoric acid which can be used according to the invention are also phosphonates and / or phosphinates.

In one embodiment of the invention, the phosphoric acid is used as 20 to 85 wt .-%, in particular 30 to 70 wt .-% solution in water. Particularly good results have been found in the treatment with a 40 to 50 wt .-% phosphoric acid solution in water. These solutions may optionally contain further additives.

In step c) of the process according to claim 1, the surface-treated fiber mat obtained from step b) is pressed into a fiberboard.

In principle, various methods are known to those skilled to compress glued lignocellulose fibers to a fiberboard. Preferably it is a hot pressing at step c). Suitable temperatures for the compression in step c) of the method according to claim 1 or one of its embodiments are temperatures of 150 ° C to 250 ° C, preferably from 160 ° C to 240 ° C, particularly preferably from 180 ° C to 230 ° C. At temperatures in these ranges, the process can be carried out particularly economically. Optimum results can be obtained if the pressing is carried out at a pressing temperature of at least about 150 ° C.

The pressing factor in hot pressing is preferably 2 to 15 s / mm, preferably 2 to 12 s / mm, and particularly preferably 4 to 12 s / mm. The term "press factor" is understood to mean in particular the residence time of the lignocellulose-containing fiberboard in seconds per millimeter thickness or thickness of the finished pressed lignocellulose-containing fiberboard in the press.

For economic and procedural reasons, it has proved to be advantageous if a specific pressing pressure (active pressure on the plate surface) of 50 to 300 N / cm ² , is used during pressing. Such pressures ensure a particularly good bonding of the lignocellulose-containing fibers together. In addition, a high strength of the lignocellulose-containing fiberboard can be achieved with such a pressing pressure.

Another object of the invention is a fiberboard, in particular a obtainable by the method according to claim 1 fiberboard. Preferably, the fiberboard consists essentially of lignocellulose-containing fibers. In the "essential" here means up to 80, 85, 90, 95, 98 or 99 wt .-%, based on the total weight of the fiberboard. However, it is possible that it contains other additives. The fiberboard may be a single-layer or multi-layer fiberboard. Preferably, the fiberboard is a DHF, UDF, LDF, MDF, or HDF board. In a particularly preferred embodiment, the fiberboard is a DHF board. Preferably, the DHF plate corresponds manufactured by the method according to claim 1 of standard EN 14964: 2007-01.

In one embodiment, the fiberboard has a thickness of 8 to 30 mm, preferably 10 to 22 mm and particularly preferably 12 to 20 mm.

In another embodiment, the apparent density of the fiberboard is 500 to 700 kg / m ³ , preferably 550 to 650 kg / m ^3, and particularly preferably 580 to 625 kg / m ³ . The density can be determined according to EN 323: 93-08.

In another embodiment, the fibers of the fiberboard are glued with an isocyanate-based binder, preferably a PMDI based. With these binders can be dispensed with the addition of a curing agent.

In a further embodiment, the fiberboard on at least one positive or non-positive connection element, in particular a groove and / or spring. For this purpose, at least one of the edge surfaces of the fibreboard can be designed such that it can be connected to another edge surface of another fiberboard. Preferably, the connection is a tongue and groove connection or bung. It is particularly preferred if the groove, spring and / or bouncing is round, oval, conical or angular. Preferably, the connection between the fiberboard is form-fitting. Particularly preferably, the connection is positively, perpendicular to the fiberboard plate level.
The person skilled in such groove-spring connections or bounces are basically known. Under tongue and groove connection or bung understood compounds that can be plugged together at their edges or edges or nested. In the tongue and groove connection, the two fiberboard panels to be joined to the edge surfaces or edges may each have a groove into which a so-called spring is inserted or inserted as a connecting third component. But it is also conceivable that the at zusammenzusteckenden fiberboard having an edge surface or edge at least one groove and the other edge surface or edge at least one spring. In a particular embodiment, the fiber board has a groove on at least one edge surface and a spring on at least one other edge surface. When bunging a spring can be incorporated in half the width of the edge of one of the two components to be connected.

This connectivity is particularly advantageous in the case of the DHF boards obtainable by the method according to claim 1, since, in addition to the increased fungal resistance, a sufficiently secured outer skin can be achieved in roofing structures. Moreover, the tongue-and-groove form-fitting connection or the bung, but also the hydrophobized surface, can be used to improve the water flow over the surface of the DHF board and protect the untreated edge surfaces.

Another object of the invention is a roof or wall component. This roof or wall component contains or consists of at least one fiber board, which is produced by the method according to claim 1 or one of its embodiments. In this case, the fiberboard may be a DHF plate having two different surfaces. Preferably, in this, based on the house, internal surface of the DHF plate was treated with an inorganic Brönsted acid in step b). The roof or wall component obtainable by the process according to claim 1 or one of its embodiments, in particular the DHF board, has, as described above, a darker color on the treated surface. This has the advantage that the treated (and thus during installation, for example, to be addressed inside) main side of the roof or wall component, in particular the DHF plate, can be easily distinguished from the untreated main page. Thus, the invention provides a user-friendly product, since confusion of the outward to be addressed with the inwardly to be addressed main page of the roof or wall component, in particular the DHF plate, can be largely avoided.

The invention also further generally relates to the use of an inorganic Bronsted acid in fiberboard manufacture to increase the resistance of the fiberboard to fungal attack wherein the Bronsted inorganic acid is selected from the group consisting of phosphoric acid, phosphorous acid, hypophosphorus acid. Phosphonic acid and mixtures thereof. Since inorganic Bronsted acids according to claim 14 were not previously known as biocide, this possibility of use in fiberboard production was surprising. This is especially true against the background that mushrooms usually prefer an acidic environment for their growth (pH 2 to 4) and therefore it does not suggest to increase the fungus resistance or resistance of a surface by an acid treatment. The person skilled in the art would rather have expected that the acid lowers the pH of the material and thus favors the growth of fungi. According to the invention, phosphoric acid, phosphorous acid, hypophosphorous acid, phosphonic acid and a mixture thereof are used.

Another object of the invention is the use of an inorganic Bronsted acid in the surface treatment of a fiber mat in the manufacture of fibreboard for hydrophobing and / or increasing the resistance of the fiberboard against fungal attack. Particularly good results are obtained when phosphoric acid, phosphorous acid, hypophosphorous acid, phosphonic acid or a mixture thereof is used.

For the uses according to the invention, the above statements on the method and products according to the invention apply accordingly.

Figur 1

zeigt eine Faserplatte 1, die nach dem Verfahren gemäß Anspruch 1 hergestellt wurde. Die Faserplatte 1 weist zwei Hauptseiten 2 und 3 auf, wobei eine die Oberseite 2 und die andere die Unterseite 3 der Faserplatte 1 bildet, die im Zuge ihrer Herstellung jeweils mit einer anorganischen Brönsted-Säure in Schritt b) behandelt wurden. Die Bereiche 2' und 3' skizzieren die Deckschichten der beiden Hauptseiten, deren Beständigkeit gegenüber Pilzbefall durch die Behandlung mit der anorganischen Brönsted-Säure erhöht wurde. Diese Bereiche 2' und 3' sind optisch durch eine Dunkelfärbung gekennzeichnet. Die verbleibenden Flächen 4 stellen die Kanten der Faserplatte 1 dar.

Figur 2a

zeigt schematisch die Herstellung einer Faserplatte 1' nach einer Ausführungsform des Verfahrens gemäß Anspruch 1, bei der eine der beiden Hauptseiten mit einer anorganischen Brönsted-Säure in Schritt b) behandelt wurde. Auf eine Fasermatte 5, die im Wesentlichen aus mit Bindemitteln beleimten lignocellulosehaltige Fasern besteht, wird eine Flüssigkeit 6 enthaltend eine anorganische Brönsted-Säure von oben aufgesprüht. Danach wird die behandelte Fasermatte 5 in einer Heißpresse 7 unter Einwirkung von erhöhtem Druck und erhöhter Temperatur zu der Faserplatte 1' verpresst. Bei der Faserplatte 1', die im Anschluss an Heißpresse 7 dargestellt ist, ist die Oberseite 2 und die behandelte Deckschicht 2', die mit der anorganischen Brönsted-Säure behandelt wurden, nach oben orientiert dargestellt.

Figur 2b

zeigt schematisch die Herstellung einer Faserplatte 1" nach einer Ausführungsform des Verfahrens gemäß Anspruch 1, bei der beide Hauptseiten, d.h. die Oberseite 2 und die Unterseite 3, mit einer anorganischen Brönsted-Säure in Schritt b) behandelt wurden. Eine Flüssigkeit 6 enthaltend eine anorganische Brönsted-Säure wird durch Aufsprühen auf einem Formband 8 vorgelegt. Danach wird auf dieser vorgelegten Flüssigkeit 6 eine Fasermatte 5, die im Wesentlichen aus mit Bindemitteln beleimte lignocellulosehaltige Fasern besteht, bereitgestellt. Anschließend wird die Flüssigkeit 6 auf die nach oben zeigende Oberfläche der Fasermatte 5 von oben aufgesprüht. Zuletzt wird die von beiden Hauptseiten behandelte Fasermatte 5 in einer Heißpresse 7 unter Einwirkung von erhöhtem Druck und erhöhter Temperatur zu der Faserplatte 1" verpresst. Bei der Faserplatte 1", die im Anschluss an die Heißpresse 7 dargestellt ist, ist die Oberseite 2 (bzw. die Deckschicht 2"), die mit der anorganischen Brönsted-Säure behandelt wurde, nach oben und die Unterseite 3 (bzw. die Deckschicht 3") nach unten orientiert dargestellt.

Particular embodiments of the invention will be explained by way of example with reference to figures. An obtainable by the method according to claim 1 fiberboard is for example in FIG. 1 shown. Embodiments of the method according to claim 1 are schematically shown in FIGS FIGS. 2a and 2 B shown.

FIG. 1

shows a fiberboard 1, which was prepared by the method according to claim 1. The fiberboard 1 has two main sides 2 and 3, one forming the upper side 2 and the other the lower side 3 of the fiberboard 1, which were each treated with an inorganic Bronsted acid in step b) in the course of their preparation. Areas 2 'and 3' outline the topsheets of the two major sides whose resistance to fungal attack was enhanced by the treatment with the inorganic Brönsted acid. These areas 2 'and 3' are optically characterized by a dark color. The remaining surfaces 4 represent the edges of the fiberboard 1.

FIG. 2a

1 schematically shows the production of a fiberboard 1 'according to one embodiment of the method according to claim 1, in which one of the two main sides has been treated with an inorganic Brönsted acid in step b). On a fiber mat 5, which consists essentially of binder-coated lignocellulosic fibers, a liquid 6 containing an inorganic Brönsted acid is sprayed from above. Thereafter, the treated fiber mat 5 is pressed in a hot press 7 under the action of elevated pressure and elevated temperature to the fiberboard 1 '. For the fiberboard 1 'shown following hot press 7, the top 2 and the treated top layer 2' treated with the inorganic Bronsted acid are oriented upwardly.

FIG. 2b

schematically shows the production of a fiberboard 1 "according to an embodiment of the method according to claim 1, wherein both main sides, ie the top 2 and the bottom 3 were treated with an inorganic Brönsted acid in step b). A liquid 6 containing an inorganic Brönsted acid is introduced by spraying on a forming belt 8. Thereafter, a fiber mat 5, which consists essentially of lignocellulose-containing fibers glued with binders, is provided on this introduced liquid 6. Subsequently, the liquid 6 is sprayed onto the upward-facing surface of the fiber mat 5 from above. Finally, the fiber mat 5 treated from both main sides is pressed into the fiber plate 1 "in a hot press 7 under the action of elevated pressure and elevated temperature the cover layer 2 "), which has been treated with the inorganic Bronsted acid, is oriented upwards and the underside 3 (or cover layer 3") oriented downwards.

The invention will be described in more detail by way of example with reference to exemplary embodiments.

Example 1: Production of fiberboard

In this example, four reference plates were made according to an MDF process commonly used in the wood industry. The experimental panel 1 according to an embodiment, i. with treatment of both surfaces of the fiber mat with an inorganic Bronsted acid.

1. Technical parameters for reference plates 1 to 4 and test plate 1:

• Binder: emulsifiable PMDI (eMDI) type (IBOND MDF EN 4330 / Fa. Huntsman) 2% paraffin emulsion (w / w) - Type Pro A18 (Sasol)
• Raw material: Coniferous wood fibers (pine and spruce wood)
• Plate thickness: 8 mm
• Plate density: 600 kg / m ³
• Pressing temperature: 200 ° C
• Pressing factor: 10 sec / mm

2. Preparation of reference plates 1 to 4:

The reference plates 1 to 4 were produced in duplicate according to the MDF process commonly used in the wood industry. Reference plates 1 to 4 were prepared without treatment with an inorganic Brönsted acid.

3. Preparation of the experimental plate 1:

The test panel 1 was prepared in duplicate according to an embodiment of the method according to claim 1. Thereby, a fiberboard was obtained, the two major sides of which had been treated with phosphoric acid during production.

During production of the test panel 1, the glued fiber mat was additionally included in the fiber mat shaping and shortly before the press entry

1. 1.) Vorlegen der Phosphorsäure auf dem Formband,
2. 2.) Faserstreuung auf das behandelte Formband und Fasermattenformung,
3. 3.) Aufsprühen der Phosphorsäure auf die nach oben zeigende Oberfläche der Fasermatte,
4. 4.) Heißverpressen zu einer Faserplatte.

Phosphoric acid surface treated. The surface treatment was carried out in the order given below:

1. 1.) presentation of the phosphoric acid on the forming belt,
2. 2.) fiber scattering on the treated forming belt and fiber mat forming,
3. 3.) spraying the phosphoric acid on the upwardly facing surface of the fiber mat,
4. 4.) Hot pressing to a fiberboard.

The amount of phosphoric acid in steps 1) and 3) was 30 g (100% phosphoric acid) per m ² .

3. Composition of the reference plates 1 to 4 and the experimental plate 1:

The composition of the reference plates 1 to 4 and the experimental plate 1 is summarized in Table 1. <B> Table. 1 </ b> Composition of fiberboard Treatment with phosphoric acid eMDI (w / atro fibers) Reference plate 1 No 3% Reference plate 2 No 4% Reference plate 3 No 5% Reference plate 4 No 6% Trial plate 1 Yes 4%

In determining the mechanical properties, the following results were obtained:

Tensile strength according to EN319 (transverse tensile strength, average of 10 individual tests)

• Reference plate 2: 0.57 N / m ²
• Experimental plate 1: 0.56 N / m ²

The results show that the good mechanical properties were maintained despite the additional treatment with the phosphoric acid.

Swelling test according to EN 317 (average of 10 individual tests)

• Reference plate 2: 9.9%
• Experimental plate 1: 9.4%

The results show that the treatment with the phosphoric acid did not adversely affect the swelling. There was even a slight reduction in swelling.

In the case of the treated test panel 1, a markedly smooth surface was observed in comparison to the reference panel 2. Even after the swelling test, the treated test panel 1 showed no detached fibers.

When wetting the surfaces of the surfaces of the reference plate 2 and the test plate 1, the water droplets percolate more clearly and faster in the test plate 1 than in the reference plate 2. Also, the surface of the test plate 1 seemed to be much smoother than that of the reference plates 1 to 4 ,

When comparing the color of the fiberboard, it was found that the experimental panel 1 had a markedly darker color of the two major sides than the reference panels. When looking at the thickness cross-section, it was also shown that only the cover layers of the test panel 1 were darker in color (thickness of the colored cover layer about 2 mm). The core of all fiber boards produced had approximately the same color. This darkening of the surface of the experimental plate 1 could be attributed to the phosphoric acid treatment.

Example 2: Determination of resistance to fungal attack

The resistance of the fiberboard from Example 1 to fungal attack was determined in accordance with the standard EN ISO 846: 1997 "Determination of the action of microorganisms on plastics".

To test the resistance to fungal attack, test bodies of the reference plate 2 and the test plate 1 from Example 1 were incubated over 4 weeks by the action of test organisms on different nutrient media (see point 3, experiments A, B and B '). At the end of the incubation period, the growth of the specimens was assessed visually to determine fungal growth (experiment A) or fungistatic efficacy (experiment B, B ') (see point 4, evaluation).

1. Equipment and test equipment:

Test specimens: After one-week conditioning (20 ° C, 65% RH) of the reference plate 2 and the test plate 1 of Example 1 nine specimens were cut out in the dimension 5x5x0.8 cm. Test organisms: Aspergillus niger Penicillum sp. Derived mineral salt solution: 2 g NaNO ₃ 0.7 g of KH ₂ PO ₄ 0.393 g K ₂ HPO ₄ H ₂ O 0.5 g KCl 0.5 g of MgSO ₄ .7H ₂ O dissolved in 1000 ml of tap water (pH 6 - 6.5) About 0.1 g Tween 80 was added to 1 L stock mineral salt solution and the solution was subsequently sterilized.

2. Cultivation of stock cultures and solutions:

The test organisms were first precultivated on malt extract agar plates. After the agar surfaces were completely overgrown, the fungal spores were harvested by means of the mineral salt solution with the aid of a Drigalskispatels.

On the surface of a nutrient agar plate completely covered with aerial mycelium, 5 ml (in 4 repetitions) of this solution were pipetted. A total of 4 plates were used. The solutions were pooled.

This solution was then filtered through an extraction tube with cotton wool (sterile). The germ count was determined with the Thomakammer. The final bacterial count was a CFU of 4 × 10 ⁷ / ml. This solution was diluted with mineral salt solution to a density of 10 ⁶ CFU / ml, thus obtaining the spore suspension for the experiments.

200 μl of this spore suspension were used for experiments A, B and B '.

3. Determination of the resistance of the test bodies to fungi 3.1. Preparation of culture media for experiment A, B and B ' 3.1.1. Incomplete agar medium for experiment A:

To the stock mineral salt solution was added so much agar that an agar concentration of 20 g / l was obtained. Then glasses with a volume of 750 ml were filled with 150 ml of agar and sealed with a lid, which was provided centrally with a cotton plug, and steam sterilized.

3.1.2. Complete agar medium for experiments B and B ':

For the preparation of the complete agar, the incomplete agar from 3.1.1. with glucose, so that a glucose concentration of 30 g / l was obtained. Then glasses with a volume of 750 ml were filled with 150 ml of agar and sealed with a lid, which was provided centrally with a cotton plug, and steam sterilized.

3.2 Description and Performance of Experiment A: Mushroom Growth Test

In experiment A, the test bodies were applied to the incomplete agar (see point 3.1.1.), Which was previously inoculated with a spore suspension of the test organisms. If the test body contains no components that can be used for the fungi, the fungi can not develop any mycelium and can overgrow the test specimen or attack the test specimens through their metabolic products. Test A is suitable for assessing the basic resistance of the test bodies to fungal attack in the absence of organic contaminants.

Execution:

In each case, three test specimens of the reference plate 2 and the test plate 1 of Example 1 were used. For this purpose, the incomplete agar from point 3.1.1. with 200 .mu.l spore suspension from point 2 inoculated. The respective test body was applied directly to the agar and incubated at 24 ° C / RH for 4 weeks.

3.3 Description and execution of experiments B and B ': Fungistatic activity

In tests B and B ', the test bodies were applied to the complete agar (see point 3.1.2.), Which was previously inoculated with a spore suspension of the test organisms. Experiments B and B 'are suitable for assessing the principal fungistatic action or property of the test bodies against fungal attack in the presence of organic contaminants. Even if the test bodies do not contain any nutrients, the fungi can overgrow the test bodies and attack the test bodies through their metabolic products. A growth inhibition on the Test body or on the culture medium (inhibition zone) indicates a fungicidal or fungistatic activity or equipment of the test body.

Execution:

In each case, three test specimens of the reference plate 2 and the test plate 1 from Example 1 were used in experiments B and B '. For this purpose, the complete agar from item 3.1.2. with 200 .mu.l spore suspension from point 2 inoculated.

In experiment B, the respective test body was applied directly to the complete agar and incubated at 24 ° C / RH for 4 weeks.

In experiment B ', the complete agar was first incubated until its surface was completely overgrown with the test organisms. Thereafter, the respective test body was applied to the complete agar and incubated at 24 ° C / RH for 4 weeks.

4. Evaluation of Experiments A, B and B ':

The evaluation of the incubated test specimens from experiments A, B and B 'was done visually. The results are summarized in Table 2. <B> Table. 2 </ b> Overview of the evaluation of experiments A, B and B '. Growth of surface strong (++); middle (+), with the main sides and edges overgrown; medium (+/-), with only the edges and not the main sides overgrown; no vegetation (-). Test body out Test body no. eMDI (w / atro fibers) Visual assessment experiment A Visual assessment trial B Visual assessment trial B ' Reference plate 2 R 2-1 4% ++ + + Reference plate 2 R 2-2 4% + ++ ++ Reference plate 2 R 2-3 4% + + + Trial plate 1 V 1-1 4% + - - Trial plate 1 V 1-2 4% - - +/- Trial plate 1 V1-3 4% +/- +/- +/-

Each of the values given in Table 2 represents an average of 3 independent visual assessments made by 3 different people.

In the test specimens of the reference plate 2 resulted in all experiments a strong to medium fungal growth. For the test specimens which were rated "medium", the fungal growth spread to the surface of the main side pointing upwards as well as to the edges of the respective test specimen.

In the test specimens of the test plate 1 resulted in all experiments mainly a medium to no and only in one case a strong fungal growth. In the test specimens which were rated "medium", the fungal growth only extended to the edges of the respective test specimen. Since the edges were not treated with the phosphoric acid (and thus were not made resistant to the fungal infection), fungal growth was to be expected at the edges. The growth on the untreated edges can thus be regarded as a positive control for the integrity of the microorganism used. The area of the top The main side, which had been treated with phosphoric acid, was not overgrown.

If one compares the reference plate 2 with the test plate 1, a clear reduction of the fungal growth can already be detected by the surface treatment of the phosphoric acid.

Claims (15)

1. Method for manufacturing a fibre board (1; 1'; 1"), comprising the steps:

   a) providing a fibre mat (5) containing glued, lignocellulose-containing fibres,

   b) completely or partially bringing into contact at least one surface (2; 3) of one of the two main sides of the fibre mat (5) from step a) with an inorganic Bronsted acid, wherein the inorganic Bronsted acid is selected from the group consisting of phosphoric acid, phosphorous acid, hypophosphorous acid, phosphonic acid and their mixtures,

   c) pressing the surface-treated fibre mat (5) obtained in step b) into a fibre board (1; 1'; 1"), whose core (4) remains acid free.
2. Method according to claim 1, characterised in that the inorganic Bronsted acid used in step b) is used in the form of a liquid (6), which contains the inorganic Bronsted acid in a concentration of 20 to 85 wt%, preferably 30 to 70 wt% and particularly preferably 40 to 55 wt% in relation to the total weight of the liquid.
3. Method according to claim 2, characterised in that the quantity of the inorganic Bronsted acid applied in the case of the complete or partial bringing into contact in step b) is 3 to 150 g/m², preferably 15 to 100 g/m² and particularly preferably 25 to 75 g/m², in relation to the surface of the fibre mat (5) treated in step b).
4. Method according to any one of claims 1 to 3, characterised in that the inorganic Brønsted acid has a pk_s value of less than 4, less than 3 or less than 2.5.
5. Method according to any one of claims 1 to 4, characterised in that the complete or partially bringing into contact in step b) takes place by spraying the inorganic Bronsted acid or the liquid (6) containing the inorganic Bronsted acid.
6. Method according to any one of claims 1 to 5, characterised in that the time between the complete or partial bringing into contact with the inorganic Bronsted acid in step b) and the pressing in step c) is 1 to 40 seconds, preferably 2 to 30 seconds and in particular preferably 2 to 20 seconds.
7. Method according to any one of claims 1 to 6, characterised in that both surfaces (2; 3) of the two main sides of the fibre mat (5) are treated in step b).
8. Method according to any one of claims 1 to 7, characterised in that the glued lignocellulose-containing fibres provided in step a) were glued with an isocyanate-based binder, in particular a PMDI-based binder.
9. Method according to any one of claims 1 to 8, characterised in that the pressing in step c) takes place at a temperature of 150°C to 250°C, preferably of 160°C to 240°C, in particular preferably of 180°C to 230°C and/or a pressing factor of 2 to 15 s/mm, preferably 2 to 12 s/mm and in particular preferably 4 to 12 s/mm.
10. Method according to any one of claims 1 to 9, characterised in that the lignocellulose-containing fibres are wood fibres.
11. Method according to any one of claims 1 to 10, characterised in that the fibre board (1; 1'; 1") is selected from a DHF, UDF, LDF, MDF or HDF board.
12. Fibre board (1; 1'; 1") manufactured according to the method according to any one of claims 1 to 11.
13. Roof or wall component containing or consisting of the fibre board (1; 1'; 1") according to claim 12, wherein the fibre board (1; 1'; 1") is a DHF board with two different surfaces (2; 3), wherein the surface (2; 3) of the DHF board lying on the inside in relation to the house construction were treated with an inorganic Bronsted acid in step b) by the method indicated in claim 1.
14. Use of an inorganic Bronsted acid in the case of fibre board manufacture to increase the resistance of the fibre board to fungal infestation, wherein the inorganic Bronsted acid is selected from the group consisting of phosphoric acid, phosphorous acid, hypophosphorous acid, phosphonic acid and their mixtures.
15. Use of an inorganic Bronsted acid in the case of the surface treatment of a fibre board (5) in fibre board manufacture to hydrophobise and/or to increase the resistance of the fibre board (1; 1'; 1") to fungal infestation, wherein the surface treatment means the complete or partial bringing into contact of at least one surface (2; 3) of one of the two main sides of the fibre mat (5) and wherein the core (4) of the fibre board (1; 1'; 1") remains acid free.

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