DE102016108551B3 - Fibrous plate with increased resistance to fungal attack and process for their preparation - Google Patents

Abstract

The invention relates to a fiberboard obtainable by compressing binder-coated, lignocellulosic fibers, wherein at least one polymeric mono-guanidine compound is concentrated in the region of at least one of the two surfaces of the fiberboard. Furthermore, the invention also relates to a process for producing the fiberboard according to the invention, comprising a) providing a fiber mat containing glued, lignocellulose-containing fibers, b) treating at least one of the two surfaces of the fiber mat from step a) with a polymeric mono-guanidine compound and c) Pressing the surface-treated fiber mat obtained from step b) into a fiberboard. Another object of the invention is a roof or wall component containing or consisting of the fiberboard according to the invention, wherein it is a DHF plate with two different surfaces in the fiberboard, and wherein the relative to the house construction interior surface of the DHF plate with a polymeric mono-guanidine compound was treated in a method specified in the claims. Further, the invention also relates to the use of a polymeric mono-guanidine compound in fiberboard manufacture to increase the resistance of the fiberboard to fungal attack.

Description

The invention relates to a fiberboard with increased resistance to fungal attack and a process for their preparation. Another object of the invention is a roof or wall component, which consists of such a fiberboard or contains. Furthermore, the invention relates to the use of polyhexamethyleneguanidine (PHMG), its salt or a mixture thereof in the manufacture of fibreboard to increase the resistance of the fibreboard to fungal attack.

Fiberboard is widely used in building construction, especially in interior and loft conversions, as well as in furniture, 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 Unterbeplankung and insulation of roof structures. Different types of fiberboard are known to those skilled in the art. These are described, for example, in "Taschenbuch der Holztechnik" by A. Wagenführ and F. Scholz, Hanser Verlag, 2012, on pages 146 to 149. If here or elsewhere "plate" is mentioned, then it is meant a cuboid flat product, which is defined by six 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 sheets (vapor-permeable and moisture-resistant fiberboard) are preferably used as under-cover panels for covering roofs and walls. 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.

In order to prevent mold growth in fiberboard, an attempt has already been made in the prior art to use various substances having a biocidal or fungicidal action in the manufacture of fibreboard. Chemicals that prevent the infestation by wood-destroying and -verfärbende fungi or insects (preventive wood protection) or in the event of an already occurred infestation killing harmful organisms (wood preservative) are usually always contain biocides as effective ingredients. Biocides are classified in Biocide Regulation (EU) No 528/2012.

However, a convincing solution, which would have prevailed in practice in the production of fiberboard, has not yet been proposed.

A disadvantage of the biocides proposed so far is that they are highly harmful to health and, on the other hand, can be poorly integrated into the resins used in fiberboard production and / or are incompatible with them.

Examples of 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 preservatives are many Combinations of inorganic salts with mostly water-insoluble organic active ingredients. The latter are rendered water-emulsifiable / dispersible with the aid of emulsifiers or dispersants and thus rendered water-dilutable (therefore "water-based"). Water-based or water-soluble wood preservatives are inter alia in the EP 2 146 571 B1 and EP 1 813 402 A2 described.

DE 10 2005 051 716 A1 relates to a binder composition for bonding wood fibers and / or particles to a wood material, the binder composition containing a reaction product of at least one binder and at least one additive selected from the group consisting of fatty acids and fatty acid derivatives. DE 10 2005 051 716 A1 further relates to wood-based materials made with the binder composition, their preparation and the use of fatty acids and fatty acid derivatives as an additive in the production of wood-based materials.

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 of 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.

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 affect human health due to their potential emission by evaporation, attrition, or otherwise release. 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.

Furthermore, in the manufacture of fibreboard, extreme processing temperatures prevail, for example when drying the preliminary or intermediate products of the fiberboard and / or during pressing. For example, the wood preservatives proposed hitherto can be washed out of the intermediate product of the fibreboard during the production process or rendered partially or wholly inoperative on account of the mechanical and / or thermal treatment. Also, the compatibility with the other substances used in the production of fiberboard must be considered. Reactions of the components with one another can not only lead to instability, but also to undesired discoloration of the end product. The fewest biocides are therefore suitable for processing in a fiberboard.

In addition, in the interests of sustainable raw material use, it is important to find a biocide that does not adversely affect the quality of recyclable materials. Biocides based on metals such as silver, copper or zinc therefore appear unsuitable. Their accumulation represents a serious problem in the treatment of waste water in municipal sewage treatment plants and the compliance with limit values after their thermal utilization.

The biocide will continue to be active for a long time. Sufficient fixation of the biocide in the surface of the fiberboard would therefore be desirable.

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 their production, by the sufficient protection against fungal attack with little effort, in particular by low entry of foreign substances into the fiberboard and less to no increase in the cost of producing the fiberboard, is achieved.

This object is achieved by the fiberboard according to claim 1, the method according to claim 8, the roof or wall component according to claim 16, and the use according to claim 18. Particular embodiments of the invention are given in the dependent claims.

The invention relates to a fiberboard obtainable by compressing binder-coated lignocellulosic fibers, wherein at least one polymeric mono-guanidine compound is concentrated in the region of at least one of the two surfaces of the fiberboard, and the polymeric mono-guanidine compound is selected PHMG, its salt and a mixture of it.

Surprisingly, it has been found that by using a polymeric mono-guanidine compound, the abovementioned problems known from the prior art can be largely avoided or reduced. Practical experiments have shown that the concentration of the polymeric mono-guanidine compound in the region of at least one of the two surfaces of the fiberboard can be used to obtain fiberboards which have increased resistance to fungal attack.

Polymeric mono-guanidine compounds are mainly used as disinfectant auxiliary components for disinfecting the skin or mucous membrane, in wound antiseptics, in hand disinfectants, for pure surface disinfection, for example by applying and wiping a guanidine-containing solution, in the medical field for controlling bacteria or for water disinfection, for example in swimming pools known. Polymeric mono-guanidine compounds can also be used as an additive in emulsion paint. The WO 2010/106002 A1 describes a polymer blend containing a polymeric mono-guanidine compound. Here, the polymeric mono-guanidine compound is introduced into an already finished polymer and processed into a powder. This powder can be incorporated in commercial emulsion paint and applied as an antimicrobial paint on metal surfaces.

The DE 198 00 400 A1 relates to substituted guanidine derivatives, a process for their preparation and their use for controlling animal pests. The EP 1 500 595 B1 relates to methods of protecting food from microbial spoilage while it is being stored in the package. The EP 1 500 595 B1 further relates to packaging and packaging material for perishable products, preferably food. The procedure of EP 1 500 595 B1 includes the brief treatment of the surface of the packaging or packaging material coming into contact with the products with a solution of guanidine-containing biocidal polymers.

The application of polymeric mono-guanidine compounds in the field of fiberboard or their production is not yet known. In the list of disinfectants of VAH (mhp Verlag 2015), which contains all preparations certified by the disinfectant commission, guanidine derivatives, for example, are stated "Due to their narrow spectrum of action, guanidines [...] are preferred for the mucosa with favorable human toxicological properties - and Wundantiseptik used. Because of their remanence, they are found as additive components in skin antiseptics and hand sanitizers, or they are used in combination with other agents. "

In light of this, it was not obvious to those skilled in the art that the polymeric mono-guanidine compounds such as PHMG would exhibit sufficient antimicrobial activity against the fungi that typically attack wood. The microorganisms to be controlled in skin or surface disinfection differ fundamentally in their spectrum from those that typically attack wood. In human applications and medical surface disinfection bacteria are in the foreground. The microorganisms that typically attack wood or fibreboard are mainly fungi.

Moreover, it was not foreseeable for those skilled in the art that the polymeric mono-guanidine compounds such as PHMG would be compatible with the process conditions prevailing in fiberboard manufacturing and the chemicals used therein. In practical experiments, the polymeric mono-guanidine compounds used according to the invention selected from PHMG, its salt and a mixture thereof surprisingly exhibited a sufficient temperature resistance to high drying and pressing temperatures.

The inventive use of polymeric mono-guanine-din compounds selected from PHMG, its salt and a mixture thereof also has the advantage that they have a very low toxicity and in practical experiments, no formation of resistances to the wood-contaminating microorganisms has been shown. Furthermore, the use of polymeric mono-guanidine compounds selected from PHMG, its salt and a mixture thereof, an environmentally friendly and / or harmless product can be obtained because they contain neither a heavy metal nor biocides within the meaning of the Biocide Regulation.

Surprisingly, it has also been found that the antimicrobial effect of polymeric mono-guanidine compounds in fiberboard is probably based on a purely physical mode of action. In interactions with the microorganisms, there appears to be no chemical reaction, metabolism or uptake by the microorganisms in the polymeric mono-guanidine compounds. Without wishing to be bound by any particular scientific theory, the physical mode of action of the polymeric mono-guanidine compounds appears to be due to an ionic interaction between the cationically modified fibreboard surface and the negatively charged cell walls of the microorganisms.

However, such physical principles are not covered by the Biocidal Products Regulation (EU) No 528/2012. It defines Article 3 (1a) (biocidal products) as "any substance or mixture in the form in which it comes to the user and which contains, contains or produces one or more active substances intended for that purpose "destroying, deterring, rendering harmless, preventing their action or otherwise combating harmful organisms", other than by mere physical or mechanical action.

Furthermore, it has been found that the concentration of the polymeric mono-guanidine compound selected from PHMG, its salt and a mixture thereof in the range of at least one of the two surfaces of the fiberboard alone is sufficient to obtain a product which is resistant to fungal attack , In fact, according to the invention, even small amounts in the region of at least one of the two surfaces of the fiber board are sufficient to achieve the desired fungal resistance.

Polymeric mono-guanidine compounds which can be used according to the invention are composed of bridged mono-guanidine compounds. The polymeric mono-guanidine compound of the present invention is selected from PHMG, its salt and a mixture thereof. Mono-guanidine compounds may also be referred to as imino ureas or as carbamidines. An example of a mono-guanidine compound is guanidine, also referred to as iminomethanediamine, having the empirical formula CH ₅ N ₃ . In the polymeric mono-guanidine compounds, the bridging of the mono-guanidine compounds, such as guanidine, for example, by alkylene chains. Mono-guanidine compounds or polymeric mono-guanidine compounds are generally known to the person skilled in the art. The properties and preparation of mono-guanidine compounds or polymeric mono-guanidine compounds are described, for example, in "Ullmanns Enzyklopadie der technischen Chemie - Volume 12", Verlag Chemie, GmbH, 1976, pages 411-419. Known examples of mono-guanidine compounds are guanidine and guanidine hydrochloride. A known example of a polymeric mono-guanidine compound is polyhexamethyleneguanidine.

Polymeric mono-guanidine compounds have, as structural element, a guanidine group, which is shown below by way of example. This is in particular a mono-guanidine structural element.

wobei

• – R¹ und R² unabhängig voneinander eine lineare oder verzweigte Kohlenwasserstoffkette mit 1 bis 16 Kohlenstoffatomen oder eine mit mindestens einem Heteroatom substituierte lineare oder verzweigte Kohlenwasserstoffkette mit 1 bis 16 Kohlenstoffatomen bedeuten, wobei das mindestens eine Heteroatom ausgewählt ist aus Sauerstoff und/oder Stickstoff;
• – x = 0, 1 oder eine ganze Zahl zwischen 2 und 10 bedeuten kann und
• – n eine ganze Zahl größer oder gleich 2 bedeutet.

An exemplary polymeric mono-guanidine compound is shown schematically in formula (I),

in which

• - R ¹ and R ² independently of one another are a linear or branched hydrocarbon chain having 1 to 16 carbon atoms or a substituted with at least one heteroatom linear or branched hydrocarbon chain having 1 to 16 carbon atoms, wherein the at least one heteroatom is selected from oxygen and / or nitrogen;
• - x = 0, 1 or an integer between 2 and 10 can mean and
• - n is an integer greater than or equal to 2.

The guanidine groups contained in the polymeric mono-guanidine compounds can also be present in charged form, in particular as cations in a salt with Gegenanion.

PHMG and other polymeric mono-guanidine compounds have as guanidine structural elements only mono-guanidine structural elements. An example of a polymeric monoguanidine compound of PHMG which can be used according to the invention is shown in formula (VI).

Based on the general formulas (I), this means for the polyalkylenguanidines which can be used in accordance with the invention that R ^{1 is} an alkylene.

If here or elsewhere of polymeric mono-guanidine compounds such as PHMG is mentioned, then it also means any salts or other derivatives thereof.

The salt of the polymeric mono-guanidine compound may be selected from the group consisting of hydrochloride, chloride, hydroxide, phosphate, fluoride, bromide, iodide, formate, acetate, diphosphate, sulfate, sulfide, nitrate, thiocyanate, thiosulfate, carbonate, Maleate, fumarate, tartrate, mesylate, gluconate and toluenesulfonate, with hydrochloride, chloride, hydroxide, phosphate, diphosphate, acetate and carbonate being preferred. Particularly preferred is hydrochloride and / or chloride. The salts of the polymeric mono-guanidine compounds show a lower corrosive effect, so that the metallic devices used in the production of fiberboard are spared and also improves the range of applications. Regardless of the lower corrosivity increased by the preferred ions, the environmental compatibility of the product or its degradation products.

The inventively employable polymeric mono-guanidine compound selected from PHMG, its salt and a mixture thereof can be used together with or in a mixture with another additive. This additive may be selected from the group consisting of other biocides, quaternary ammonium compounds and mixtures thereof.

In one embodiment, this additive is a quaternary ammonium compound. The quaternary ammonium compound may be selected from the group consisting of didecyldimethylammonium chloride (DDAC), dimethyloctadecyl [3- (trimethoxysilyl) propyl] ammonium, dimethyltetradecyl [3- (trimethoxysilyl) propyl] ammonium chloride, alkyl (C _12-18 ) dimethylbenzylammonium chloride ( ADBAC (C _12-18 )), alkyl (C _12-16 ) dimethylbenzyl ammonium chloride (ADBAC / BKC (C ₁₂ -C 16)), didecyldimethylammonium chloride (DDAC (C _8-10 )), alkyl (C _12-14 ) dimethylbenzylammonium chloride ( ADBAC (C _12-14 )), alkyl (C _12-14 ) ethylbenzylammonium chloride (ADEBAC (C _12-14 )), dialkyl (C _8-10 ) dimethylammonium chloride, alkyl (C _12-14 ) dimethyl (ethylbenzyl) ammonium chloride.

As already mentioned, even lower concentrations of the polymeric mono-guanidine compounds in the region of at least one of the two surfaces of the fiberboard are sufficient to achieve the desired antimicrobial effect. In fact, when the polymeric mono-guanidine compound is concentrated near the surface of the fiberboard, the core of the fiberboard may even be kept substantially free of the polymeric mono-guanidine compound. Thereby, the amounts of the polymeric mono-guanidine compound, which must be used to increase the resistance to fungi, can be significantly reduced. This has the advantage that the entry of foreign substances can be kept as low as possible and thereby also material costs can be saved.

The fiberboard of the present invention comprises at least one polymeric mono-guanidine compound selected from PHMG, its salt and a mixture thereof concentrated in the region of at least one of the two surfaces of the fiberboard. In particular, the polymeric mono-guanidine compound may be concentrated in the region of both surfaces of the fiberboard. Where "concentrated", "concentrated in the area of at least one of the two surfaces of the fiberboard," or "concentrated in the surface (s)" is meant here or elsewhere, it is meant that the concentration of the polymeric mono-guanidine compound is higher in the area of the surface or on the surface of the fiberboard, than in the core thereof. In particular, in the region or on the surface of the fiberboard, the highest concentration of the polymeric mono-guanidine compound in the fiberboard according to the invention. Thus, according to the invention, there is a concentration gradient with respect to the polymeric mono-guanidine compound from at least one surface, starting in the direction of the fiberboard core, where the concentration of the polymeric mono-guanidine compound is lower than in the region of or at the surface of the fiberboard.

Fiberboard core, as used herein, includes the center of the fiberboard resulting from the cuboid shape of the fiberboard as the intersection of the spatial diagonals. In one embodiment, fiberboard core means the middle layer around the center of the fiberboard, which layer is substantially parallel to the surface of the fiberboard and has a mean layer thickness of 1, 2, 3, 4, or 5 mm. In one embodiment, fiberboard core means the center of the fiberboard or a substantially spherical volume about the center of the fiberboard, the radius of which may be 1, 2, 3, 4, or 5 mm.

In one embodiment, by "surface of the fiberboard" is meant the entire surface layer in which the polymeric mono-guanidine compound is concentrated. The thickness of this treated surface layer is dependent on the penetration depth of the polymeric mono-guanidine compound. The superficial layer in which the polymeric mono-guanidine compound is concentrated must be differentiated from the middle layer that forms or comprises the core of the fiberboard, and which is preferably substantially free of polymeric mono-guanidine compounds. Typically, the thickness of the surface layer in which the polymeric mono-guanidine compound is concentrated, starting from the surface of the fiberboard, is at least 0.01, 0.05, 0.1, 0.5, 1, 2, 3 or 5 mm into the interior of the fiberboard. The superficial layer in which the polymeric mono-guanidine compound is concentrated preferably runs substantially parallel to the surface of the fiberboard.

If thickness (eg layer thickness or plate thickness) is mentioned here, then this refers to the average thickness, which may be z. B. as an average of 5 thickness measurements at different positions of the fiberboard results.

Preferably, the core of the fiberboard is substantially free of polymeric mono-guanidine compounds, that is, there is a region inside the fiberboard that is substantially free of the polymeric mono-guanidine compound.

In another embodiment of the fiberboard there is a concentration gradient of polymeric mono-guanidine compound between at least one surface of the fiberboard and its center. The fiberboard has, in particular in its core, a range of less than 0.3, 0.1, 0.05 or 0.01 wt .-% of polymeric mono-guanidine compound, based on the dry matter (atro) of the lignocellulose-containing Materials, and more preferably contains substantially no polymeric mono-guanidine compound in its core.

For this reason, since the polymeric mono-guanidine compound is concentrated in the region of at least one of the two surfaces of the fiberboard, the amount of the polymeric mono-guanidine compound in the fiberboard of the present invention is also expressed as the area concentration relative to the surface rather than the volume concentration , based on the total volume of the fiberboard, defined. Due to the comparatively small total amount of the polymeric mono-guanidine compounds, the cost of the fiberboard according to the invention compared to a fiberboard without biocide are only slightly increased. It is also not necessary to significantly change the process for their preparation. Ultimately, the entry of foreign matter into the fiberboard is so low that it does not lose its safety from an environmental point of view.

The polymeric mono-guanidine compound, which is concentrated in the region of at least one of the two surfaces of the fiberboard, preferably has a surface concentration of 2 to 200 g / m ² , particularly preferably from 4 to 80 g / m ² and particularly preferably from 6 to 30 g / m ² , based on the respective surface of the fiberboard on.

The fiberboards of the invention also showed in practical experiments no worse mechanical properties than conventional fiberboard. This was surprising because the skilled person would have expected a damaging effect on the cell walls of the fibers and thus a deterioration of the mechanical properties of the final product due to the putative effect of the polymeric mono-guanidine compounds (cationic surface modification). Moreover, since the polymeric mono-guanidine compounds are concentrated only in the region of at least one of the two surfaces of the fiberboard and the core of the fiberboard can be substantially free thereof, possible fiber structure damage and mechanical properties substantially determined by the core of the plate are avoided , remain as undisturbed as possible.

Another advantage that has been shown in practice is that the polymeric mono-guanidine compounds are also suitable for a variety of fiber-binder combinations. The addition of additional substances can impair the properties of the binder and thus lead to insufficient binder effect and / or mechanical properties of the final product. As a result of the fiberboard construction selected according to the invention, which provides for a concentration of the polymeric mono-guanidine compounds only in the region of at least one of the two surfaces of the fiberboard, such problems can be largely avoided.

Furthermore, it was surprising that, despite the water solubility of the polymeric mono-guanidine compounds, the known problems of customary water-soluble wood preservatives can be avoided. Thus, no harmful or environmentally harmful residues or emissions could be detected in the fiberboard of the invention. The incorporation of the polymeric mono-guanidine compounds onto the fiber mat seems to result in fixation of the polymeric mono-guanidine compounds during compression to the fiberboard.

In addition, it has been found in practical experiments that the fungal resistance is maintained over time, thus showing no serious stability or Auswaschproblematik. This was surprising since polymeric mono-guanidine compounds are usually water-soluble. One skilled in the art would expect a water-soluble substance used in outdoor fiberboards, such as a DHF board, to come into regular contact with water or moisture to leach out over time and wash out the product over time would lose its antimicrobial properties.

The fiberboard according to the invention may be a single-layer or multilayer fiberboard. The fiberboard according to the invention preferably 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. The fiber board may contain other additives such as fire retardants, solvents, solubilizers, viscosity adjusting agents, wetting agents, emulsifiers, pH-adjusting agents, fats, fatty acids, biocides or stabilizers.

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, the sugars being acetyl- as well as methyl-substituted Groups may have. 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 lignocellulose-containing fibers are preferably wood fibers. These wood fibers can be produced by defibration of wood particles, wood fibers, wood chips or finely divided wood material. Preferred types of wood for the production of a fiberboard obtainable by the process according to the invention are, for example, softwoods, in particular pine and / or spruce wood.

Most 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 according to the invention corresponds to the standard EN 14964: 2007-01.

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

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. However, it is also conceivable that in the fibreboards to be assembled together, one edge surface or edge has at least one groove and the other edge surface or edge has 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 the invention since, in addition to the increased fungal resistance, they can also be used to achieve a sufficiently secured outer skin in roof structures. Moreover, the tongue-and-groove form-fitting connection or the bung, but also the hydrophobized surface, can be used to improve the flow of water across the surface of the DHF board and protect the untreated edge surfaces.

• a) Bereitstellen einer Fasermatte enthaltend beleimte, lignocellulosehaltige Fasern,
• b) Behandeln mindestens einer der beiden Oberflächen der Fasermatte aus Schritt a) mit einer polymeren Mono-Guanidin-Verbindung ausgewählt aus PHMG, dessen Salz und einer Mischung daraus,
• c) Verpressen der aus Schritt b) erhaltenen, oberflächenbehandelten Fasermatte zu einer Faserplatte.

The fiberboard according to the invention can be produced in a particularly practical manner by a process which comprises the following steps:

• a) providing a fiber mat containing glued, lignocellulose-containing fibers,
• b) treating at least one of the two surfaces of the fiber mat from step a) with a polymeric mono-guanidine compound selected from PHMG, its salt and a mixture thereof,
• c) pressing the surface-treated fiber mat obtained from step b) into a fiberboard.

The inventive method is based on known from the prior art process for fiber board production, wherein in addition to the usual process steps, a surface treatment of the fiber mat with a polymeric mono-guanidine compound selected from PHMG, its salt and a mixture thereof before being pressed into a fiberboard becomes.

The person skilled in the art is fundamentally familiar with various methods of producing fiberboard by compressing binder-coated lignocellulose-containing fibers, in particular into DHF, HDF or MDF boards. Due to the advantages described above, the treatment with the polymeric mono-guanidine compound can be easily integrated into a variety of production processes, such as a conventional process for producing DHF, HDF or MDF boards. The production of fiberboards by the dry or wet process and other methods is described for example in "wood materials and glues" by M. Dunky and P. Niemz, Springer Verlag, 2002 pages 149-152. A description of the properties of the different types of fiberboard, process steps for the preparation of this and required equipment and materials are also described in "Taschenbuch der Holztechnik" by A. Wagenführ and F. Scholz, Hanser Verlag, 2012, on pages 225-245.

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.

In principle, it would also be conceivable the fibers before the provision of the fiber mat, z. B. already in the defibration, in the digester or in the refiner to treat with the polymeric mono-guanidine compound. 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 of the invention sees the treatment of the fibers only after their gluing at the stage of the fiber mat, d. H. in step b). Since by this procedure, the treated fibers are subjected to only one thermal step, namely compression to a fiberboard, the inventive method is particularly gentle on the fibers and the polymeric mono-guanidine compounds used in this case selected from PHMG, its salt and a Mix of it.

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 surface treatment takes place, in the process according to the invention even low concentrations of the polymeric mono-guanidine compound selected from PHMG, its salt and a mixture thereof, based on the total weight of the fiber mat, are sufficient to ensure increased resistance to fungi.

Another advantage of the treatment according to the invention with the polymeric mono-guanidine compound selected from PHMG, its salt and a mixture thereof is that this insert can be easily integrated into conventional processes of the wood industry for the production of fiberboard. The water-solubility of the PHMG used in the method according to the invention 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 polymeric mono-guanidine compound selected from PHMG, its set and a mixture thereof can be applied via a blowline, for example. Due to the water solubility of the polymeric mono-guanidine compound selected from PHMG, its salt and a mixture thereof, it is not necessary to introduce organic solvents which on the one hand constitute a fire hazard and on the other hand constitute an additional, potentially harmful, emission source.

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

The inventive method 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 inventive method 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 surface or major side of the DHF plate. A particularly advantageous feature of this is that a DHF plate with increased resistance to fungal attack can be obtained without expensive intermediate steps, elaborate impregnation processes subsequent to the preparation, or further chemical aftertreatment.

For the method according to the invention, what has already been said about the fibreboard according to the invention applies. According to the methods known from the prior art, the method according to the invention initially provides that in step a) a fiber mat which contains glued, lignocellulose-containing fibers is provided.

The provision is made in conventional processes for the production of fiberboard, z. B. by scattering lignocellulosic, glued fibers to 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. The fiber mat preferably 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. 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.

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.

In principle, the method according to the invention is suitable for a large number of binder-wood fiber combinations. Examples of binders which can be used according to the invention 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 of the invention, a system based on urea-formaldehyde resins (UF), melamine-reinforced urea-formaldehyde resins (MUF), melamine resin, melamine-formaldehyde resin, melamine-urea is used as binder for the gluing Phenol-formaldehyde resins (MUPF), phenol-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). In particular, polymeric diphenylmethane diisocyanate can be used as the polymeric diisocyanate.

In one 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.

The inventive method further provides that in step b) at least one of the two surfaces of the fiber mat from step a) is treated with a polymeric mono-guanidine compound selected from PHMG, its salt and a mixture thereof.

If the "surface of the fiber mat" is mentioned here or elsewhere, this means the surface of one of the two main sides of the fiber mat or the later surfaces (or main sides) of the fiber board 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 fiber mat or of the later fiber board. The cover layer may be the most superficial layer of a single-layer or multi-layer fiberboard obtained therefrom. In another embodiment, by "surface of the fiber mat" is meant the entire superficial layer treated with a mono-polymeric guanidine compound selected from PHMG, its salt and a mixture thereof, or in which the polymeric mono-guanidine compound is selected from PHMG, its salt and a mixture of it is concentrated. This has already been defined above for the fiber board and the same applies to the superficial layer of the fiber mat. The thickness of this treated surface layer is dependent on the penetration depth of the polymeric mono-guanidine compound. The treated surface layer is to be separated from the middle layer which forms the core of the fiber mat and which does not come into contact with the polymeric mono-guanidine compound. Typically, the thickness of the treated surface layer (and thus also the penetration depth of the polymeric mono-guanidine compound into the fiber mat) is at least 0.01, 0.05, 0.1, 0.5, 1, 2, 3 or 5 mm into the interior of the fiber mat or the later fiberboard, viewed from the surface of the fiber mat or the subsequent fiberboard.

Incidentally, the fiber mat used in the method according to the invention is the same as that already mentioned above for the fiberboard according to the invention.

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.

Whenever "treating", "treating" or "treating with the polymeric mono-guanidine compound" is referred to herein or elsewhere, it is the wholly or partially contacting at least one of the surfaces of the fiber mat with the polymeric mono-guanidine compound selected from PHMG, its salt and a mixture thereof. By treating only the surface of the fiber mat with the polymeric mono-guanidine compound, the concentration of the polymeric mono-guanidine compound according to the invention in the region of at least one of the two surfaces of the fiber mat is achieved automatically, since the polymeric mono-guanidine compound not evenly distributed within the fiber mat. The penetration depth and thus the thickness of the region in which the polymeric mono-guanidine compound is concentrated, the expert can, for example, by varying the amount of used for the treatment polymeric mono-guanidine compound selected from PHMG, its salt and a mixture thereof or by varying the exposure time, d. H. the time that elapses between the treatment with the polymeric mono-guanidine compound selected from PHMG, its salt and a mixture thereof in step b) and the compression to the fiber plate in step c).

The polymeric mono-guanidine compound selected from PHMG, its salt and a mixture thereof may be sprinkled as a solid or as part of a solid composition. Preferably, however, the polymeric mono-guanidine compound is employed in the form of or as part of a liquid.

"Liquid" as used herein may mean a dilute solution of the polymeric mono-guanidine compound selected from PHMG, its salt, and a mixture thereof (ie, the liquid then comprises the polymeric mono-guanidine compound and a diluent ). On the other hand, "liquid" as used herein may also generally mean a liquid composition containing the polymeric mono-guanidine compound selected from PHMG, its salt and a mixture thereof, and optionally other components. This liquid may additionally contain further additives, in particular a quaternary ammonium compound.

For surface treatment, a polymeric mono-guanidine compound selected from PHMG, its salt and a mixture thereof is used in step b) of the process according to the invention. Good for the polymeric mono-guanidine compound already said above. The polymeric mono-guanidine compound is preferably present as (possibly diluted) liquid, ie in liquid form. The polymeric mono-guanidine compound is preferably present in the liquid in a concentration of 10, 15, 20, 25, 35, 40, 50, 60, 70, 75, 80, 85, 90, 95, 98 or 99% by weight. %, based on the total weight of the liquid. At a concentration of 10% by weight, this means that 10 g of the pure polymeric mono-guanidine compound are weighed out and supplemented with the liquid to 100 g. Particularly preferred as the treatment liquid in step b) is an aqueous solution of the polymeric mono-guanidine compound. The liquid may further contain further additives, for example release agents and / or quaternary ammonium compounds.

Preferably, the polymeric mono-guanidine compound in step b) of the process according to the invention as part of a liquid composition and / or in a liquid in a concentration of 10 to 85 wt .-%, particularly preferably from 20 to 70 wt .-% and particularly preferably used from 25 to 55 wt .-%, based on the total weight of the liquid. In particular, the liquid is an aqueous solution of the polymeric mono-guanidine compound, which may also contain other additives. The concentrations of the polymeric mono-guanidine compound in "% by weight" or "% by weight" given here are understood to mean the proportion by mass. That is, it means the mass of the polymeric mono-guanidine compound based on the total mass of the liquid.

PHMG can be used as such, as a salt or as a mixture thereof. For the PHMG used according to the invention as the polymeric mono-guanidine compound and its salts, what has already been said above applies.

The preferred amount of the polymeric mono-guanidine compound selected from PHMG, its salt and a mixture thereof, which is applied in step b) is 2 to 200 g / m ² , more preferably 4 to 80 g / m ^2, and particularly preferred 6 to 30 g / m ² , based on the surface of the fiber mat treated in step b). 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 polymeric mono-guanidine compound selected from PHMG, its salt and a mixture thereof is distributed evenly over the surface of the top and / or bottom. When using dilute preparations containing the polymeric mono-guanidine compound, the above g / m ² data refer to g of pure polymeric mono-guanidine compound per m ² treated surface. If, for example, 50 g of a 50% strength by weight solution of the polymeric mono-guanidine compound are sprayed onto a 1 m ² surface in step b), the amount of polymeric mono-guanidine compound used here is 25 g / m ² .

According to the invention, the polymeric mono-guanidine compound is PHMG, its salt and / or a mixture thereof. Particularly preferred is PHMG · HCl.

In a further embodiment of the invention, PHMG is used as 10 to 85% by weight, in particular 20 to 70% by weight, solution in water. Particularly good results have been found in the treatment with a 25 to 55 wt .-% PHMG solution in water. These solutions may optionally contain further additives.

It has been found that the treatment of at least one of the surfaces of the fiber mat in step b) of the process according to the invention can be integrated in a simple and cost-effective manner into already customary production processes for fiberboard production. The provision of the fiber mat can be done by sprinkling glued fibers on a forming belt. In this case, one of the two surfaces of the fiber mat usually lies on the forming belt (here called "underside"), while the other of the two surfaces of the fiber mat points upwards. the treatment with the polymeric mono-guanidine compound selected from PHMG, its salt and a mixture thereof from step b) can be carried out on the top side and / or on the underside resting on the forming belt.

The treatment in step b) with the polymeric mono-guanidine compound selected from PHMG, its salt and a mixture thereof or the liquid containing it can be carried out, for example, by brushing or spraying. Preferably, the treatment is carried out by spraying, for. B. by means of a blowline. Furthermore, the treatment can be carried out in such a way that only the polymeric mono-guanidine compound from step b) is initially charged and then the fiber mat from step a) is provided and applied thereto. The presentation can z. B. done by spraying. However, it is also possible that first the fiber mat from step a) is provided and then at least one of the two surfaces is treated with the polymeric mono-guanidine compound from step b).

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 polymeric mono-guanidine compound selected from PHMG, its salt and a mixture thereof from step b). In this case, the polymeric mono-guanidine compound or the liquid containing it is preferably sprayed on.

In another embodiment, first the polymeric mono-guanidine compound selected from PHMG, its salt and a mixture thereof or the liquid containing it are placed on the forming belt and then provided the fiber mat. The presentation of the polymeric mono-guanidine compound or the liquid containing it is preferably carried out by spraying. In a particular embodiment, the upwardly facing surface is additionally treated with the polymeric mono-guanidine compound selected from PHMG, its salt and a mixture thereof 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 fiberboards, both surfaces of the fiber mat are treated with the polymeric mono-guanidine compound selected from PHMG, its salt and a mixture thereof, the bottom being treated first. In this case, the treatment time of the underside can take place for 1 to 40 seconds, preferably 2 to 30 seconds and in particular 2 to 20 before the treatment of the upper side of the fiber mat.

The treatment is advantageously carried out during or after the usual fiber mat scattering and / or fiber mat shaping. 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 reaction time or the time between the treatment with the polymeric mono-guanidine compound selected from PHMG, its salt and a mixture thereof in step b) and the compression in step c) can in principle be varied. In one embodiment, the time between the treatment with the polymeric mono-guanidine compound 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 the treatment with the polymeric mono-guanidine compound in step b) and the compression in step c) may be 5 minutes, 2 minutes, 40 seconds, 30 seconds or 20 seconds, wherein said lower and lower Upper limits can be combined with each other. Preferably, the time between the treatment with the polymeric mono-guanidine compound in step b) and the compression in step c) is 1 to 40 seconds, more preferably 2 to 30 seconds, and most preferably 2 to 20 seconds.

Furthermore, it is provided in the process according to the invention that in step c) 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, step c) is a hot pressing. Suitable temperatures for the compression in step c) of the process according to the invention 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.

The invention also provides fiberboard obtainable by the method described above.

Another object of the invention is a roof or wall component, in particular such a house-building. This roof or wall component contains or consists of at least one fiberboard according to the invention. In this fiberboard, the at least one polymeric mono-guanidine compound selected from PHMG, its salt and a mixture thereof is preferably concentrated in the region of the surface which, in terms of house construction, points inwards. Thus, the fiberboard is preferably oriented within the roof or wall member such that the interior surface of the building is within the range in which the at least one polymeric mono-guanidine compound selected from PHMG, its salt and a mixture thereof is concentrated ,

The fiberboard may, for example, have been produced by the method according to the invention or one of its embodiments. Preferably, the fiberboard is a DHF board having two different surfaces. Preferably, this was based on the house construction, internal surface of the DHF plate with a polymeric mono-guanidine compound selected from PHMG, its salt and a mixture thereof in step b) treated.

The polymeric mono-guanidine compound selected from PHMG, its salt and a mixture thereof, as described above, is compatible with the manufacturing process and fiberboard manufacturing conditions. In particular, it does not appear to react with components of the fiberboard which could result in undesirable discoloration of the product. By using the polymeric mono-guanidine compound thus unwanted discoloration of the product are largely avoided.

Thus, according to the invention, a product having a uniform coloring of the surface can be obtained. If both surfaces of the fiberboard or of the roof or wall component are not treated, one of the sides, in particular the treated surface, can be marked to distinguish the treated from the non-treated surface of the fiberboard or of the roof or wall component. The fiberboard or roof or wall components according to the invention can therefore contain such a marking.

The invention also generally relates to the use of a polymeric mono-guanidine compound selected from PHMG, its salt and a mixture thereof in fiberboard manufacture for increasing the resistance of the fiberboard to fungal attack. For the inventive use, the above statements apply to the fiberboard according to the invention and to the inventive method accordingly.

Polymeric mono-guanidine compounds have not heretofore been known as a biocide in fiberboard production. Their possibility of use in the manufacture of fibreboard was surprising to a person skilled in the art. This is particularly true against the background that wood or fiberboard from another spectrum of microorganisms, especially fungi, are attacked, whereas the polymeric mono-guanidine compounds have been used in their previous use primarily against bacteria.

If here or elsewhere "mushroom" or "fungal attack" is mentioned, then "mushroom" means the broad definition for 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 as compared to a non-biocidal, fungicidal and / or fungistatic-acting 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.

In particular, the invention also contemplates the use of PHMG in the surface treatment of a fibrous mat in fiberboard manufacture to increase the resistance of the fiberboard to fungal attack, particularly for use in the inventive method described above. Particularly good results are obtained when PHMG, a salt thereof or a mixture thereof is used.

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

1 shows a fiberboard 1 , which was prepared by the process according to the invention. The fiberboard 1 has two main pages 2 and 3 on, with one the top 2 and the other the bottom 3 the fiberboard 1 which were each treated with a polymeric mono-guanidine compound in step b) of the method according to the invention. The areas 2 ' and 3 ' sketch the superficial layers of the two major sites whose resistance to fungal attack was enhanced by treatment with the polymeric mono-guanidine compound. in these areas 2 ' and 3 ' the at least one polymeric mono-guanidine compound is concentrated. The core of the fiberboard remains free of the polymeric mono-guanidine compound. The remaining areas 4 put the edges of the fiberboard 1 represents.

2a shows schematically the production of a fiberboard 1' according to one embodiment of the method according to the invention, in which one of the two main sides is treated with a polymeric mono-guanidine compound in step b). On a fiber mat 5 consisting essentially of binder-coated lignocellulosic fibers, becomes a liquid 6 containing a polymeric mono-guanidine compound sprayed from above. Thereafter, the treated fiber mat 5 in a hot press 7 under the action of increased pressure and elevated temperature to the fiberboard 1' pressed. At the fiberboard 1' that following hot press 7 is shown is the top 2 and the treated topcoat 2 ' , which were treated with the polymeric mono-guanidine compound, shown oriented upwards. In that area 2 ' at least one polymeric mono-guanidine compound is concentrated.

2 B shows schematically the production of a fiberboard 1'' according to an embodiment of the method according to the invention, in which both main sides, ie the upper side 2 and the bottom 3 were treated with a polymeric mono-guanidine compound in step b). A liquid 6 containing a polymeric mono-guanidine compound by spraying on a forming belt 8th submitted. After that, it is applied to this liquid 6 a fiber mat 5 consisting essentially of binder-coated lignocellulosic fibers. Subsequently, the liquid 6 on the upwardly facing surface of the fiber mat 5 sprayed from above. Finally, the fiber mat treated by both main sides becomes 5 in a hot press 7 under the action of increased pressure and elevated temperature to the fiberboard 1'' pressed. At the fiberboard 1'' After the hot press 7 is shown is the top 2 (or the cover layer 2 '' ) treated with the polymeric mono-guanidine compound, up and down 3 (or the cover layer 3 '' ) oriented downwards. In that area 2 '' and 3 '' at least one polymeric mono-guanidine compound is concentrated.

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, a reference plate was made according to an MDF process commonly used in the wood industry. The test panels 1 and 2 were according to an embodiment of the invention, i. H. with treatment of both surfaces of the fiber mat with PHMG.

1. Technical parameters for reference plate 1 and test plate 1:

• Binder: emulsifiable PMDI (eMDI) type (IBOND MDF EN 4330 / Huntsman)
• 3% paraffin emulsion (w / w) - Type Pro A18 (Sasol)
• Raw material: fiber material as softwood (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 the reference plate:

The reference plate was produced in duplicate according to the MDF process commonly used in the wood industry. The reference plate was made without treatment with PHMG.

3. Preparation of the experimental plates 1 and 2:

The test panels 1 and 2 were prepared in duplicate according to an embodiment of the method according to the invention. As a result, fiberboards were obtained, the two major sides of which had been treated with PHMG during manufacture.

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

In the production of the test panels 1 and 2, the glued fiber mats were additionally surface-treated with PHMG (25% solution of PHMG · HCl in water) during the fiber mat molding and shortly before the press entry. The surface treatment was carried out in the order given below:

• 1.) placing the PHMG on the forming belt by spraying the PHMG solution,
• 2.) fiber scattering on the treated forming belt and fiber mat forming,
• 3.) spraying the PHMG solution onto the upwardly facing surface of the fiber mat,
• 4.) Hot pressing to a fiberboard.

The amount of PHMG in step 1) and 3) per surface was 48 g / m ² for the test panel 1 and 24 g / m ² for the test panel 2 per surface

3. Composition of reference plate and experimental plates:

The composition of the reference plate and the experimental plates is summarized in Table 1. Tab. 1 Composition of the fiberboard Treatment with PHMG (amount PHMG [g / m ² ]) eMDI (w / atro fibers) reference plate No 3% Trial plate 1 Yes (48 g / m ²⁾ 3% Experimental plate 2 Yes (24 g / m ² ) 3%

Subsequently, swelling according to EN 317 and tensile strength according to EN 319 of the reference plate and the test plates 1 and 2 were determined.

Swelling test according to EN 317 (mean of 5 individual tests)

• Reference plate: 10.1%
• Experimental plate 1: 11.0%
• Trial plate 2: 10.1%

The results show that treatment with PHMG did not adversely affect the swelling. The experimental plate 2 showed the same swelling as the reference plate. The experimental plate 1 showed only a slight increase in swelling.

Tensile strength according to EN 319 (transverse tensile strength, average of 5 individual tests)

• Reference plate: 0.42 N / m ²
• Experimental plate 1: 0.49 N / m ²
• Experimental plate 2: 0.48 N / m ²

The results show that the good mechanical properties were maintained despite the additional treatment with PHMG. The experimental plates 1 and 2 even showed a slightly higher strength than the reference plate. In particular, the experimental panel 2 showed approximately the same mechanical properties as the experimental panel 1. This was surprising since the experimental panel 1 had a slightly higher swelling, which is why the skilled person would have expected a decrease in the tensile strength. When comparing the color of the reference plate and the experimental plates 1 and 2, it was found that the experimental plates 1 and 2 had no discoloration as compared with the reference plate.

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 and the test plate 1 from example 1 were incubated for 4 weeks with a test organism 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 (Test A) or fungistatic efficacy (Test B, B ') (see Item 4, Evaluation). 1. Equipment and test equipment: Test specimens: After one week of air conditioning (20 ° C, 65% RH) of the Reference plate and the test plate 1 of Example 1 were nine specimens in the dimension 5 × 5 × 0.8 cm cut out. Test organism: 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 MgSO ₄ .7H ₂ O dissolved in 1000 ml of tap water (pH 6-6.5) About 0.1 g of Tween 80 was added to 1 L stock mineral salt solution added, the solution was then sterilized.

2. Cultivation of stock culture and solutions:

The test organism was 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 and thus obtained the trace 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 organism. 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 and the test plate 1 from 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 piece was applied directly to the agar and incubated at 24 ° C / 90% 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 organism. 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. Growth inhibition on the test piece or on the growth medium (inhibition zone) indicates fungicidal or fungistatic activity or equipment of the test piece.

Execution:

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

In experiment B, the respective test body was applied directly to the complete agar and incubated at 24 ° C / 90% RH for 4 weeks.

In experiment B ', the complete agar was first incubated until its surface was completely overgrown with the test organism. Thereafter, the respective test piece was applied to the complete agar and incubated at 24 ° C / 90% 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. Tab. 2 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 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 R-1 3% ++ ++ - reference plate R-2 3% + + ++ reference plate R-3 3% - ++ - Trial plate 1 V-1 3% - - - Trial plate 1 V-2 3% - - - Trial plate 1 V-3 3% +/- - -

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

The test specimens of the reference plate showed predominantly 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.

The test specimens of the test plate showed in all experiments mainly no to medium fungal growth. In the test piece, which was rated "medium", the fungal growth only extended to the edges of the respective test piece. The area of the upwardly facing main page treated with PHMG was not overgrown.

If one compares the reference plate with the experimental plate 1, a clear reduction of the fungal growth is already detectable by the surface treatment with PHMG.

Claims (19)

Fiberboard obtainable by compressing binder-coated, lignocellulose-containing fibers, characterized in that at least one polymeric mono-guanidine compound is concentrated in the region of at least one of the two surfaces of the fiberboard, the polymeric mono-guanidine compound being selected from polyhexamethyleneguanidine (PHMG) , its salt and a mixture of it. Fiberboard according to claim 1, characterized in that the area of at least one of the two surfaces of the fiberboard in which the PHMG, its salt or a mixture thereof is concentrated, starting from the surface of the fiberboard, is at least 0.01, 0.05, 0.1, 0.5, 1, 2, 3 or 5 mm into the interior of the fiberboard, Fiberboard according to one of claims 1 or 2, characterized in that between at least one surface of the fiberboard and its center a concentration gradient of PHMG, its salt or a mixture thereof and the fiberboard in this case, in particular in its core has a range of less than 0 , 3, 0.1, 0.05 or 0.01% by weight, based on the dry matter (atro) of the lignocellulosic material, and more preferably no PHMG, its salt or a mixture thereof in its core. Fiberboard according to one of claims 1 to 3, characterized in that the fiberboard the PHMG, its salt or a mixture thereof in the region of at least one of the two surfaces of the fiberboard in a surface concentration of 2 to 200 g / m ² , preferably from 4 to 80 g / m ² and particularly preferably from 6 to 30 g / m ² , based on the respective surface of the fiberboard. Fiberboard according to one of claims 1 to 4, characterized in that the fiberboard has a bulk density of 500 to 700 kg / m ³ , preferably 550 to 650 kg / m ³ and particularly preferably 580 to 625 kg / m ³ and / or a thickness of 6 to 30 mm, preferably from 10 to 22 mm and particularly preferably from 12 to 20. Fiberboard according to one of claims 1 to 5, characterized in that the fiberboard is a DHF, UDF, LDF, MDF or HDF board. Fiberboard according to one of claims 1 to 6, characterized in that the lignocellulose-containing fibers are wood fibers. Process for producing a fiber board according to one of Claims 1 to 7, comprising the steps of: a) providing a fiber mat containing glued, lignocellulose-containing fibers, b) treating at least one of the two surfaces of the fiber mat from step a) with PHMG, its salt or a mixture thereof, c) pressing the surface-treated fiber mat obtained from step b) into a fiber board. A method according to claim 8, characterized in that the used in step b) PHMG, its salt or a mixture thereof in a liquid in a concentration of 10 to 85 wt .-%, preferably 20 to 70 wt .-% and particularly preferably 25 to 55 wt .-%, based on the total weight of the liquid, is used. Method according to one of claims 8 or 9, characterized in that the amount of the applied in the treatment in step b) PHMGs, its salt or a mixture thereof 2 to 200 g / m ² , preferably 4 to 80 g / m ² and especially preferably 6 to 30 g / m ² , based on the treated in step b) surface of the fiber mat is. Method according to one of claims 8 to 10, characterized in that the treatment in step b) is carried out by spraying PHMG, its salt or a mixture thereof or the liquid containing the PHMG, its salt or a mixture thereof. Method according to one of claims 8 to 11, characterized in that the time between the treatment with the PHMG, its salt or a mixture thereof in step b) and the compression in step c) 1 to 40 seconds, preferably 2 to 30 seconds and particularly preferably 2 to 20 seconds. Method according to one of claims 8 to 12, characterized in that the glued lignocellulose-containing fibers provided in step a) were glued with an isocyanate-based binder, in particular a PMDI-based binder. Method according to one of claims 8 to 13, characterized in that in step b) both surfaces of the fiber mat are treated. Method according to one of claims 8 to 14, characterized in that the pressing in step c) at a temperature of 150 ° C to 250 ° C, preferably from 160 ° C to 240 ° C, particularly preferably from 180 ° C to 230 ° C and / or a pressing factor of 2 to 15 s / mm, preferably 2 to 12 s / mm and particularly preferably 4 to 12 s / mm. Roof or wall component containing or consisting of the fiberboard according to one of claims 1 to 7. Roof or wall component according to claim 16, wherein the fiberboard is a DHF board with two different surfaces, characterized in that in the house-building-based surface of the DHF board PHMG, its salt or a mixture thereof in the Concentrated at least one of the two surfaces of the DHF plate. Use of PHMG, its salt or a mixture thereof in fiberboard manufacture for increasing the resistance of the fiberboard according to any one of claims 1 to 7 to fungal attack. Use of PHMG, its salt or a mixture thereof according to claim 18, characterized in that the polymeric mono-guanidine compound is used in the surface treatment of a fiber mat in the manufacture of fibreboard to increase the resistance of the fiberboard against fungal attack.

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