EP3455042B1 - Fibreboard with increased resistance to fungal attack and method for producing the same - Google Patents

Description

The invention relates to a fiberboard with increased resistance to fungal attack and a process for its production. Another object of the invention is a roof or wall component which consists of or contains such a fiberboard. The invention further relates to the use of a polymeric mono-guanidine compound in the manufacture of fiberboard to increase the resistance of the fiberboard to fungal attack.

Fiberboard is used in a variety of ways in house construction, especially in interior and roof construction, as well as in furniture construction, for example as a wall element for outdoor or indoor use, as a carrier board for laminate floors, for front and rear fronts of furniture or for under-planking and insulation of roof structures. Different types of fiberboard are known to those skilled in the art. These are for example in " Taschenbuch der Holztechnik "by A. Wagenführ and F. Scholz, Hanser Verlag, 2012, on pages 146 to 149 described. If one speaks of "plate" here or elsewhere, it means a cuboid flat product which is defined by six surfaces: four edge surfaces and an upper and lower side, the upper side and the lower side here together and in delimitation to the Edge surfaces are referred to as "main sides" or "surfaces of the plate".

In the construction sector, DHF boards (open to diffusion and moisture-resistant fiber boards) are preferably used as under-deck boards for cladding roofs and walls. Good moisture resistance or good protection against microbial infestation is desirable here, since DHF boards can be exposed to water or moisture for extended periods. For example, this exposure can be caused by external weather conditions or by evaporating water Interiors, especially in new buildings. In new buildings, after plastering the walls, there is still residual moisture that evaporates over time and rises towards the roof structure. In practice, moisture condenses on the DHF panels installed in the roof structure, and mold can form within a short time, especially on the inward-facing surface of the DHF panel. This problem also occurs with insufficiently sealed or damaged roofs (the surfaces of the DHF panel facing outwards can also be affected) and unventilated, cold attics.

An increased risk of mold formation can also occur with fiberboard, which have been installed in walls inside and outside as well as back fronts of furniture that are directed towards an outer wall. It is therefore desirable to provide improved wood fiber boards, in particular DHF boards, in which at least one of the two main sides of the fiber board has an increased resistance to fungal attack.

Apart from the main sides, an increase in the fungal resistance can also be desirable for the edge surfaces of the fiberboard. However, this aspect mostly fades into the background because the edges usually have a much smaller surface area compared to the main sides of the fiberboard. In addition, the edges of the fiberboard are typically in contact with each other during installation, so that the edges are not directly exposed to moisture.

In order to avoid mold formation in fiberboard, attempts have already been made in the prior art to use various substances with a biocidal or fungicidal effect in the manufacture of fiberboard. Chemicals that prevent infestation by wood-destroying and discoloring fungi or insects (preventive wood protection) or should kill harmful organisms in the event of an infestation (combating wood protection) usually contain always biocides as effective components. Biocides are listed in the Biocides Regulation (EU) No. 528/2012 classified.

A convincing solution, which would also have been successful in the production of fiberboard, has not yet been proposed.

A disadvantage of the previously proposed biocides is that they are extremely harmful to health and, on the other hand, are difficult to integrate into and / or incompatible with the resins used in the manufacture of fiberboard.

Examples of biocide wood preservatives are coal tar oils (creosols), water-soluble / water-based preservatives (borates) or solvent-based preservatives (triazoles). The tar oils show a good antimicrobial activity. However, it should be borne in mind that these are harmful to health, have a strong smell and are difficult to paint and glue. The water-soluble protective agents are often combinations of inorganic salts with mostly water-insoluble organic active ingredients. The latter are made 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 among others in the EP 2 146 571 B1 and EP 1 813 402 A2 described.

The EP 2 146 571 B1 describes a furniture and / or interior fitting that is treated with an antimicrobial treatment by impregnation with a resin composition. The resin composition contains a biocidal composition
from an organic biocidal compound (Isothiazolinone) and a nanoscale metal oxide (ZnO, MgO or Al2O3). A disadvantage of such a combination, however, is that emulsifiers are added as solubilizers, which can additionally promote the swelling of the fiberboard due to their emulsifying effect.

US 2012/1 5651 7 A1 describes a method for treating wood. The wood to be treated is contacted with a composition containing monoesters, diesters or triesters or a mixture thereof. Also disclosed US 2012/1 5651 7 A1 Chipboard, but not fibreboard.

US 2012/164239 A1 relates to a composition and a method for treating wood-based materials to improve their durability. The composition contains C ₁ -C ₇ monocarboxy esters and optionally PHMG.

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

Because of the disadvantages described above, many wood preservatives containing biocidal substances cannot therefore be optimally used in roofing or interior work. Furthermore, due to their potential emission through evaporation, abrasion or other release, the biocides can affect human health. However, biocides often lose their effectiveness due to gradual (natural) degradation. The water-soluble or water-based wood preservatives can, for example, be washed out of the fiberboard over time, which on the one hand reduces the antimicrobial effectiveness and on the other hand can lead to an increased environmental impact.

Furthermore, extreme processing temperatures prevail in the manufacture of fiberboard, for example when drying the preliminary or intermediate products of the fiberboard and / or when pressing. The previously proposed wood preservatives can, for example, already be washed out of the intermediate product of the fiberboard during the production process or can be rendered partially or completely ineffective on account of the mechanical and / or thermal treatment. The compatibility with the other substances used in the manufacture of fiberboard must also be taken into account. Reactions between the components can not only lead to instability, but also to undesirable discoloration of the end product. Very few biocides are therefore suitable for processing in a fiberboard.

In addition, in terms of sustainable raw material use, it is important to find a biocide that does not have a negative impact on 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 compliance with limit values after their thermal use.

The biocide is said to remain active over a long period of 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 was to be able to produce a fiberboard with increased resistance to fungi without having to use an unstable, washable or risky substance. Another aspect of the object on which the invention is based was to produce an environmentally friendly product which is distinguished by a long-lasting fungus resistance.

Furthermore, it was a further object of the invention to demonstrate a fiberboard and a method for its production, by means of which adequate protection against fungal attack is achieved with little effort, in particular through little entry of foreign substances into the fiberboard and little or no increase in the cost of producing the Fiberboard, is reached.

This object is achieved according to the invention by the fiberboard according to claim 1, the method according to claim 10, the roof or wall component according to claim 18, and the use according to claim 20. Particular embodiments of the invention are given in the dependent claims.

1. a) Bereitstellen einer Fasermatte enthaltend beleimte, lignocellulosehaltige Fasern,
2. b) Behandeln mindestens einer der beiden Oberflächen der Fasermatte aus Schritt a) mit einer polymeren Mono-Guanidin-Verbindung,
3. c) Verpressen der aus Schritt b) erhaltenen, oberflächenbehandelten Fasermatte zu einer Faserplatte,

wobei

• mindestens eine polymere Mono-Guanidin-Verbindung im Bereich mindestens einer der beiden Oberflächen der Faserplatte konzentriert ist;
• zwischen mindestens einer Oberfläche der Faserplatte und ihrem Mittelpunkt ein Konzentrationsgefälle an polymerer Mono-Guanidin-Verbindung besteht und die Faserplatte dabei in ihrem Kern einen Bereich aufweist, in dem die Konzentration der polymeren Mono-Guanidin-Verbindung niedriger ist als im Bereich der Oberfläche der Faserplatte.

The invention relates to a fiberboard made by pressing lignocellulosic fibers glued with binder is produced in a process comprising the following steps:

1. a) providing a fiber mat containing glued, lignocellulose-containing fibers,
2. b) treating at least one of the two surfaces of the fiber mat from step a) with a polymeric mono-guanidine compound,
3. c) pressing the surface-treated fiber mat obtained from step b) into a fiberboard,

in which

• at least one polymeric mono-guanidine compound is concentrated in the region of at least one of the two surfaces of the fiber board;
• There is a concentration gradient of polymeric mono-guanidine compound between at least one surface of the fiberboard and its center, and the fiberboard has in its core an area in which the concentration of the polymeric mono-guanidine compound is lower than in the area of the surface of the fiberboard .

Surprisingly, it was found that the problems listed above and known from the prior art can be largely avoided or reduced by using a polymeric mono-guanidine compound. Practical tests have shown that the concentration of the polymeric mono-guanidine compound in the region of at least one of the two surfaces of the fiber board can be used to obtain fiber boards which have an increased resistance to fungal attack.

Polymeric mono-guanidine compounds are mainly used as disinfectant additional components for disinfecting the skin or mucous membrane, in wound antiseptics, in hand disinfectants, for pure surface disinfection, for example by applying and wiping off a solution containing guanidine, in the medical field for combating bacteria or for water disinfection, for example in swimming pools. Polymeric mono-guanidine compounds can also be used as additives in emulsion paints. 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 applied in commercially available emulsion paint and applied as an antimicrobial paint to metal surfaces.

The use of polymeric mono-guanidine compounds in the field of fiberboard or the production thereof has hitherto not been known. In the disinfectant list of the VAH (mhp Verlag 2015), which contains all preparations certified by the Disinfectant Commission, the following is stated for guanidine derivatives, for example: "Guanidines are preferred for the mucous membrane due to their narrow spectrum of action with favorable human toxicological properties - and wound antiseptics used. Because of their retentive effect, they can be found as additional components in skin antiseptics and hand disinfectants, or they are used in combination with other active ingredients. "

Against this background, it was not obvious to the person skilled in the art that the polymeric mono-guanidine compound had a sufficient antimicrobial activity against the fungi which typically infested wood. The microorganisms to be controlled in skin or surface disinfection differ fundamentally from those that typically infest wood. Bacteria are the main focus in human applications and medical surface disinfection. The microorganisms that typically infest wood or fiberboard are primarily fungi.

Moreover, it was not foreseeable for the person skilled in the art that the polymeric mono-guanidine compounds would be compatible with the process conditions prevailing in the manufacture of fiberboard and the chemicals used therein. In practical tests, the polymeric mono-guanindine compounds used according to the invention surprisingly showed sufficient temperature resistance to high dryer and pressing temperatures.

The use of polymeric mono-guanine compounds according to the invention also has the advantage that they have a very low toxicity and that practical tests have shown no development of resistance to the wood-infecting microorganisms. Furthermore, by using polymeric mono-guanidine compounds, such as polyhexamethylene guanidine, an environmentally friendly and / or harmless product can be obtained, since they neither contain a heavy metal, nor are they biocides within the meaning of the Biocide Regulation.

Surprisingly, it was also found that the antimicrobial effect of the polymeric mono-guanidine compounds in fiberboard is probably based on a purely physical principle of action. When interacting with the microorganisms, the polymeric mono-guanidine compounds do not appear to undergo any chemical reaction, metabolism or uptake by the microorganisms. Without wishing to be bound by any particular scientific theory, the physical principle of action of the polymeric mono-guanidine compounds appears to be based on an ionic interaction between the cationically modified fiberboard surface and the negatively charged cell walls of the microorganisms.

However, such physical principles of action are not covered by the Biocide Regulation (EU) No. 528/2012 . Article 3 (1) (a) defines biocidal products as "any substance or mixture in the form in which it reaches the user and which consists of, contains or produces one or more active substances, which is intended for this purpose is to destroy, deter, render harmless, prevent their effects or otherwise combat them by means other than physical or mechanical action.

Furthermore, it was found that the concentration of the polymeric mono-guanidine compound which can be used according to the invention in the region of at least one of the two surfaces of the fiberboard is sufficient to obtain a product which is resistant to fungal attack. According to the invention, it has been shown that even small amounts in the area of at least one of the two surfaces of the fiberboard are sufficient to achieve the desired resistance to fungus.

Polymeric mono-guanidine compounds which can be used according to the invention are composed of bridged mono-guanidine compounds. Mono-guanidine compounds can also be referred to as imino ureas or as carbamidines. An example of a mono-guanidine compound is guanidine, also referred to as iminomethane diamine, with the empirical formula CH ₅ N ₃ . In the polymer Mono-guanidine compounds can be used to bridge the mono-guanidine compounds, for example 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 " Ullmann's Encyclopedia of Technical Chemistry - Volume 12 ", Verlag Chemie, GmbH, 1976, pages 411-419 described. Known examples of mono-guanidine compounds are guanidine and guanidine hydrochloride. A well-known example of a polymeric mono-guanidine compound is polyhexamethylene guanidine.

Eine beispielhafte polymere Mono-Guanidin-Verbindung ist schematisch in Formel (I) dargestellt,

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.

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

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

in which

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

In one embodiment, x = 0 and R ¹ is selected from the group consisting of alkylene, oxyalkylene, alkylene diamine and oxyalkylene diamine.

According to a preferred embodiment, x = 0 and R ^{1 is} an alkylene radical of the general formula (II)

- (CH ₂ ) _m -, (II),

where m is an integer between 1 and 16, preferably between 1 and 12, particularly preferably between 1 and 8 and in particular equal to 6.

According to an alternative preferred embodiment, x = 0 and R ^{1 is} an alkylenediamine of the general formula (III),

-NH - [(CH ₂ ) - (CHR)] _n -NH- (III),

in which n is an integer between 1 and 10, in particular 1, 2 or 3, and R is hydrogen or a methyl radical. Preferred alkylenediamines of the formula (III) which can be used according to the invention are selected from the group consisting of ethylenediamine, trimethylenediamine, propylenediamine, hexamethylenediamine and mixtures thereof.

According to a further preferred embodiment, x = 0 and R ^{1 is} an oxyalkylene of the general formula (IV),

-CH ₂ -CHR- [O-CH ₂ -CHR] _n - (IV),

in which n represents 1, 2, 3, 4 or 5 and R represents hydrogen or a methyl radical. Preferred examples of the oxyalkylenes which can be used according to the invention are oxyethylene, in particular triethylene glycol and / or oxypropylene.

According to a further preferred embodiment, x = 0 and R ^{1 is} an oxyalkylenediamine of the general formula (V),

-NH-CH ₂ -CHR- [O-CH ₂ -CHR] _n -NH- (V)

in which n represents 1, 2, 3, 4 or 5 and R represents hydrogen or a methyl radical. Preferred examples of the oxyalkylene diamines which can be used according to the invention are oxyethylene diamine, in particular triethylene glycol diamine and / or oxypropylene diamine.

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 a counter anion.

The polymeric mono-guanidine compounds which can be used according to the invention are preferably polymeric mono-guanidine compounds, their salts or a mixture thereof.

Polymeric mono-guanidine compounds have only mono-guanidine structural elements as guanidine structural elements. An example of a polymeric mono-guanidine compound which can be used according to the invention is polyhexamethylene guanidine (PHMG), represented in formula (VI).

Polymeric mono-guanidine compounds which can be used according to the invention are compounds from the group consisting of polyalkylene guanidines, in particular polyhexamethylene guanidine, polyalkylenediaminguanidines, polyoxyalkylene guanidines, polyoxyalkylenediaminguanidines and their salts.
Based on the general formulas (I), for the polyalkylene guanidines, polyalkylenediaminguanidines, polyoxyalkylene guanidines, polyoxyalkylenediaminguanidines which can be used according to the invention, R ¹ and / or R ^{2 is} an alkylene, alkylenediamine, oxyalkylene and / or oxyalkylenediamine.

In a particularly preferred embodiment, polyhexamethylene guanidine (PHMG) is used as the polymeric mono-guanidine compound.

If here or elsewhere polymer mono-guanidine compounds or their special embodiments, for example PHMG, are mentioned, then they also mean any salts or other derivatives thereof.

The salt of the polymeric mono-guanidine compound can 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. Hydrochloride and / or chloride is particularly preferred. The salts of the polymeric mono-guanidine compounds show a lower corrosive effect, so that the metallic devices used in the manufacture of the fiberboard are spared and the range of applications also improves. Independently the lower corrosivity increases the environmental compatibility of the product or its degradation products due to the preferred ions.

The polymeric mono-guanidine compound which can be used according to the invention can be used together with or in a mixture with another additive. This additive can 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 can 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 the at least one of the two surfaces of the fiberboard are sufficient to achieve the desired antimicrobial effect. If the polymeric mono-guanidine compound is concentrated in the area of the surface of the fiberboard, the core of the fiberboard can even be kept substantially free of the polymeric mono-guanidine compound. As a result, the amounts of the polymeric mono-guanidine compound which must be used to increase the resistance to fungi can be considerably reduced. This has the advantage that the entry of foreign substances can be kept as low as possible and material costs can also be saved.

The fiberboard according to the invention has at least one polymeric mono-guanidine compound which is concentrated in the region of at least one of the two surfaces of the fiberboard. In particular, the polymeric mono-guanidine compound can be concentrated in the region of both surfaces of the fiber board. When here or elsewhere we speak of "concentrated", "concentrated in the area of at least one of the two surfaces of the fiberboard" or "concentrated in the surface (s)", it means 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 area or on the surface of the fiberboard there is the highest concentration of the polymeric mono-guanidine compound in the fiberboard according to the invention. There is therefore, according to the invention, a concentration gradient with respect to the polymeric mono-guanidine compound starting from at least one surface in the direction of the fiber board core, where the concentration of the polymeric mono-guanidine compound is lower than in the region of or on the surface of the fiber board.

Fiberboard core, as used here, comprises the center of the fiberboard, which results from the cuboid shape of the fiberboard as the intersection of the space diagonals. According to one embodiment, the fiberboard core means the middle layer around the center of the fiberboard, this layer running essentially parallel to the surface of the fiberboard and having an average layer thickness of 1, 2, 3, 4 or 5 mm. According to one embodiment, the fiberboard core means the center of the fiberboard or an essentially spherical volume around the center of the fiberboard, the radius of which can be 1, 2, 3, 4 or 5 mm.

In one embodiment, "surface of the fiberboard" means the entire surface layer in which the polymeric mono-guanidine compound is concentrated. The thickness of this treated surface layer depends on the penetration depth of the polymeric mono-guanidine compound. The surface layer in which the polymeric mono-guanidine compound is concentrated is that of Delimit middle layer, which forms or comprises the core of the fiberboard and which is preferably essentially 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 inside of the fiberboard. The superficial layer in which the polymeric mono-guanidine compound is concentrated preferably runs essentially parallel to the surface of the fiberboard.

If we are talking about thickness (e.g. layer thickness or plate thickness), we mean the average thickness that e.g. as an average of 5 thickness measurements at different positions of the fiberboard.

The core of the fiberboard is preferably essentially free of polymeric mono-guanidine compounds, that is to say there is an area inside the fiberboard which is essentially free of the polymeric mono-guanidine compound.

In the fiberboard according to the invention, there is a concentration gradient of polymeric mono-guanidine compound between at least one surface of the fiberboard and its center. The core of the fiberboard in particular has an area which is less than 0.3, 0.1, 0.05 or 0.01% by weight of polymeric mono-guanidine compound, based on the dry weight (atro) of the lignocellulose-containing material , and particularly preferably contains essentially 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 according to the invention is also expressed as an area concentration, based on the surface, and not as a volume concentration , based on the total volume of the fiberboard. Because of the comparatively small total amount of the polymeric mono-guanidine compounds the costs for the fiberboard according to the invention are only slightly increased compared to a fiberboard without biocide. It is also not necessary to significantly change the process for their manufacture. Ultimately, the amount of foreign substances in the fiberboard is so small 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 an area concentration of 2 to 200 g / m ² , particularly preferably 4 to 80 g / m ² and particularly preferably 6 to 30 g / m ² , based on the respective surface of the fiberboard.

In practical tests, the fiberboard according to the invention also showed no poorer mechanical properties than conventional fiberboard. This was surprising, since the person skilled in the art would have expected the cell walls of the fibers to have a damaging effect on the cell walls of the fibers and thus to impair the mechanical properties of the end product due to the presumed effect of the polymeric mono-guanidine compounds (cationic surface modification). In addition, since the polymeric mono-guanidine compounds are concentrated only in the area of at least one of the two surfaces of the fiberboard and the core of the fiberboard can remain essentially free of it, possible damage to the fiber structure is avoided and the mechanical properties, which are essentially determined by the core of the plate , remain largely unaffected.

Another advantage that has been shown in practice is that the polymeric mono-guanidine compounds are also suitable for a large number of fiber-binder combinations. The addition of additional substances can impair the properties of the binder and thus lead to insufficient binder action and / or mechanical properties of the end product. Due to the fiberboard structure chosen according to the invention, the concentration of the polymeric mono-guanidine compounds only in the area of at least one of the two surfaces of the fiberboard, such problems can be largely avoided.

It was also surprising that, despite the water solubility of the polymeric mono-guanidine compounds, the known problems of conventional water-soluble wood preservatives can be avoided. In this way, no harmful or environmentally harmful residues or emissions could be detected in the fiberboard according to the invention. Due to the introduction of the polymeric mono-guanidine compounds onto the fiber mat, the polymeric mono-guanidine compounds appear to be fixed when pressed to the fiberboard.

In addition, it was found in practical tests that the fungal resistance is retained over time, so that there are no serious problems of stability or washing out. This was surprising since polymeric mono-guanidine compounds are usually water-soluble. A person skilled in the art would expect a water-soluble substance which is used in fibreboards for outdoor use, such as, for example, a DHF board, and which regularly comes into contact with water or moisture to wash out over time and the product with time would lose its antimicrobial properties.

The fiberboard according to the invention can be a single-layer or multilayer fiberboard. The fiberboard according to the invention preferably consists essentially of fibers containing lignocellulose. “Essentially” here means up to 80, 85, 90, 95, 98 or 99% by weight, based on the total weight of the fiberboard. The fiberboard can contain further additives, for example fire retardants, solvents, solubilizers, viscosity-adjusting agents, wetting agents, emulsifiers, pH-adjusting agents, fats, fatty acids, biocides or stabilizers.

When we speak of "lignocellulose-containing fibers" here or elsewhere, we mean any type of fiber that contains lignocellulose. Lignocellulose in the sense of the invention contains lignin and cellulose and / or hemicellulose. "Cellulose" is an unbranched polysaccharide that consists of several hundred to ten thousand cellobiose units. These cellobiose units in turn consist of two molecules of glucose, which are linked via a β-1,4-glycosidic bond. "Hemicellulose" is a collective name for various components of plant cell walls. Hemicelluloses are branched polysaccharides with a shorter chain length - usually less than 500 sugar units - which are made up of different sugar monomers. Hemicellulose is essentially made up of various sugar monomers, such as, for example, glucose, xylose, arabinose, galactose and mannose, it being possible for the sugars to have acetyl and methyl-substituted groups. They have a random, amorphous structure and are easy to hydrolyze. Xylose or arabinose mainly consist of sugar monomers with five carbon atoms (pentoses). Mannose or galactose mainly consist of sugar monomers with six carbon atoms (hexoses). "Lignins" are amorphous, irregularly branched aromatic macromolecules, which occur naturally as a component of cell walls and cause the lignification of the cell there. They are composed of substituted phenylpropanol units, have a lipophilic character and are insoluble at room temperature in neutral solvents, such as water. Precursors of lignin are, for example, p-coumaryl alcohol, coniferyl alcohol and sinapyl alcohol. The molar masses 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 defibrating wood particles, wood fibers, wood chips or finely divided wood material. Preferred types of wood for producing a fiberboard obtainable by the method according to the invention are, for example, softwoods, in particular pine and / or spruce wood.

The fiberboard is particularly preferably a DHF, UDF, LDF, MDF or HDF board. In a particularly preferred embodiment, the fiber board is a DHF board. The DHF board according to the invention preferably corresponds to the standard EN 14964: 2007-01.

In one embodiment of the invention, the bulk 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 bulk density can be determined in accordance with 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 has at least one positive or non-positive connection element, in particular a tongue and groove. For this purpose, at least one of the edge surfaces of the fiberboard can be configured such that it can be connected to another edge surface of another fiberboard. The connection is preferably a tongue and groove connection or bung. It is particularly preferred if the groove, tongue and / or bung is round, oval, conical or angular. The connection between the fiberboard is preferably form-fitting. The connection is particularly preferably positive, perpendicular to the fiber board plane.

Such tongue and groove connections or bungings are known in principle to the person skilled in the art. Tongue-and-groove connection or bunging is understood to mean connections which can be plugged together or placed one inside the other at their edge surfaces or edges. In the tongue and groove connection, the two fibreboards to be connected can each have a groove on the edge surfaces or edges into which a so-called tongue is inserted or inserted as the connecting third component. However, it is also conceivable for the fiberboard to be put together to have at least one groove on one edge surface or edge and at least one tongue on the other edge surface or edge. In a special one In one embodiment, the fiberboard has a groove on at least one edge surface and a tongue on at least one other edge surface.

In the case of the plugging, a half-width spring can be incorporated into the edge of one of the two components to be connected.

This connectivity is particularly advantageous in the case of the DHF panels which can be obtained by the process according to the invention, since in addition to the increased resistance to fungi, they can also be used to achieve adequately fastened external cladding in roof structures. In addition, the tongue-and-groove form fit or the bung, but also the hydrophobized surface, enable improved water drainage over the surface of the DHF board and the untreated edge surfaces are protected.

1. a) Bereitstellen einer Fasermatte enthaltend beleimte, lignocellulosehaltige Fasern,
2. b) Behandeln mindestens einer der beiden Oberflächen der Fasermatte aus Schritt a) mit einer polymeren Mono-Guanidin-Verbindung,
3. c) Verpressen der aus Schritt b) erhaltenen, oberflächenbehandelten Fasermatte zu einer Faserplatte.

The fiberboard according to the invention is produced by a method which comprises the following steps:

1. a) providing a fiber mat containing glued, lignocellulose-containing fibers,
2. b) treating at least one of the two surfaces of the fiber mat from step a) with a polymeric mono-guanidine compound,
3. c) pressing the surface-treated fiber mat obtained from step b) into a fiberboard.

The process according to the invention is based on processes for producing fiberboard known from the prior art, in addition to the usual process steps, a surface treatment of the fibrous mat with a polymeric mono-guanidine compound is carried out before pressing to form a fiberboard.

The person skilled in the art is fundamentally familiar with various methods for producing fiberboard by pressing lignocellulose-containing binders glued with binder Fibers, especially for DHF, HDF or MDF boards, are known. Because of the advantages described above, the treatment with the polymeric mono-guanidine compound can be easily integrated in a large number of production processes, such as, for example, in a conventional process for producing DHF, HDF or MDF boards. The production of fiberboard using 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 properties of the different types of fiberboard, process steps for the production of these and the necessary equipment and materials are also 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 or multi-layer fibreboard have the following steps in common: First the wood material is treated in a stove and then fiberized. The wood material is often shredded or defibrated in a refiner. Typical process conditions for shredding or defibration that are common in industry are process temperatures of 160 to 200 ° C and pressures up to 10 bar. Then the fibers are dried if necessary and then glued. The fibers can be glued in a gluing drum by spraying. A wide variety of binders can be used in the production of fiberboard. Usually, no hardener is added to the binder in fibreboard production. The glued fibers are finally scattered into a fiber mat, which the person skilled in the art also calls "fiber cake", possibly preformed and pressed into a fiber board.

In principle, it would also be conceivable to treat the fibers with the polymeric mono-guanidine compound before the provision of the fiber mat, for example already during defibration, in the cooker or in the refiner. In this case, however, the treated fibers would have to be subjected to an additional thermal step. This can damage the fiber structure. In contrast, sees the invention Process the treatment of the fibers only after their gluing at the stage of the fiber mat, ie in step b). Since this procedure means that the treated fibers are only subjected to one thermal step, namely the pressing into a fiberboard, the process according to the invention is particularly gentle on the fibers and the polymeric mono-guanidine compounds used.

Practical tests have shown that treating the surface or the top layer of the fiber mat shortly before the press enters is sufficient for the increased resistance to fungi achieved according to the invention. Since only a surface treatment takes place, even low concentrations of the polymeric mono-guanidine compound, based on the total weight of the fiber mat, are sufficient in the process according to the invention to ensure increased resistance to fungi.

Another advantage of the treatment according to the invention with the polymeric mono-guanidine compound is that its use can be easily integrated into conventional processes in the wood industry for the production of fiberboard. The water solubility of the polymeric mono-guanidine compound used in the process according to the invention is particularly advantageous. Aqueous solutions or suspensions can be easily integrated into the usual process steps and systems used in the manufacture of fiberboard. No complex intermediate steps or process interruptions are required. The polymeric mono-guanidine compound can be applied, for example, via a blowline. Due to the water solubility of the polymeric mono-guanidine compound, no organic solvents have 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.

Another advantage over the usual water-based, non-reactive wood preservatives is that no other additives, such as Emulsifiers are required to dissolve the polymeric mono-guanidine compound and to be able to apply it to the fiber mat. This also prevents additional swelling of the fiberboard.

The method according to the invention is particularly well suited for the production of fiberboard and is not restricted to any particular fiberboard type. The fiberboard obtainable by the process can have one or more layers.

The method according to the invention has proven to be particularly practical for the production of fibrous panels open to diffusion for roof and wall construction (hereinafter referred to as "DHF panels"). In particular, the embodiments described here enable the fungus resistance of at least one surface or main side of the DHF plate to be increased in an uncomplicated manner. A particular advantage of this is that a DHF board with increased resistance to fungal attack can be obtained without complex intermediate steps, complex impregnation processes subsequent to the production or further chemical aftertreatment.

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

It is provided in the usual processes for the production of fiberboard, for example by scattering glue-containing fibers containing lignocellulose into a fiber mat. Typically, the fibers are first glued and then scattered onto a forming tape to form a fiber mat. In a further step, the fiber mat can be additionally shaped and / or smoothed on its upward-facing surface. The fiber mat preferably consists essentially of fibers containing lignocellulose. “Essentially” here means up to 80, 85, 90, 95, 98 or 99% by weight, based on the total weight of the fiber mat. The fiber mat or the fiberboard can contain further additives, for example fire protection agents, solvents, Solubilizers, viscosity-adjusting agents, wetting agents, emulsifiers, pH-adjusting agents, fats, fatty acids or stabilizers.

Typically, the lignocellulose-containing fibers are glued with a binder before, during and / or after they are sprinkled into a fiber mat. If "gluing" is used here, then it can be understood to mean all or part of the wetting with a composition which contains a binder. Such compositions are also referred to by the person skilled in the art as "glue liquor". Gluing can in particular also mean the uniform distribution of the binder-containing composition on the lignocellulose-containing fibers. The binder-containing composition can be applied, 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 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% by weight, in particular 1.0 to 16% by weight, more preferably 2.0 to 14.0% by weight or 2.0 up to 10.0% by weight, based on the dry wood weight (solid resin / dry). For many applications, it is particularly practical if the binder is used in an amount of 0.1 to 15% by weight based on the dry wood weight (solid resin / dry). The binder can be applied, 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 also 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-phenol is used as the binder for the gluing Formaldehyde resins (MUPF), phenol-formaldehyde resins (PF), polymeric diisocyanates (PMDI) and / or isocyanates. The binder is preferably an isocyanate-based binder. More preferably, the binder contains an isocyanate or consists of 80, 90, 95, 99 or 100% by weight thereof. Particularly good results are obtained if 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 binder. With these binders, it is not necessary to add a hardener.

The method according to the invention 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.

When the "surface of the fiber mat" is mentioned here or elsewhere, it means the surface of one of the two main sides of the fiber mat or the later surfaces (or main sides) of the fiberboard 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 here means the so-called "cover layer" of the fiber mat or the later fiberboard. The cover layer is the most superficial fiber layer of the fiber mat or the later fiber board. The top layer can be the most superficial layer of a single-layer or multilayer fiberboard obtained therefrom. According to another embodiment, “surface of the fiber mat” means the entire surface layer which has been treated with a monopolymer guanidine compound or in which the polymeric mono-guanidine compound is concentrated. This has already been defined above for the fiberboard and the same applies to the surface layer of the fibrous mat. The thickness of this treated surface layer depends on the penetration depth of the polymeric mono-guanidine compound. The treated surface layer must be distinguished 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 surface layer treated (and thus also the depth of penetration 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 later fiberboard.

Incidentally, what has already been said above regarding the fiberboard according to the invention applies to the fiber mat used in the method 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. In another embodiment, only the bottom of the fiber mat or both surfaces (i.e., top and bottom) of the fiber mat are treated.

If here or elsewhere we are talking about "treating", "treating" or "treating with the polymeric mono-guanidine compound", then this means bringing all or part of the surfaces of the fiber mat into contact with the polymeric mono-guanidine compound meant. 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 becomes automatically reached in the area of at least one of the two surfaces of the fiber mat, since the polymeric mono-guanidine compound is not evenly distributed within the fiber mat. The depth of penetration and thus the thickness of the region in which the polymeric mono-guanidine compound is concentrated can be determined by the person skilled in the art, for example, by varying the amount of the polymeric mono-guanidine compound used for treatment or by varying the exposure time, ie the time which between treatment with the polymeric mono-guanidine compound in step b) and pressing to the fiberboard in step c).

When the term "polymeric mono-guanidine compound" is used in the singular, this includes the plural, in particular several identical polymeric mono-guanidine compounds and several different polymeric mono-guanidine compounds and mixtures thereof.

The polymeric mono-guanidine compound can be sprinkled on as a solid or as part of a solid composition. However, the polymeric mono-guanidine compound is preferably used in the form of or as part of a liquid.

"Liquid" as used herein can mean a dilute solution of the polymeric mono-guanidine compound (i.e. the liquid then comprises the polymeric mono-guanidine compound as well as a solvent or diluent). On the other hand, "liquid", as used here, can also very generally mean a liquid composition which contains the polymeric mono-guanidine compound and, if appropriate, further components. This liquid can additionally contain other additives, in particular a quaternary ammonium compound.

A polymeric mono-guanidine compound is used for surface treatment in step b) of the process according to the invention. What has already been said above applies to the polymeric mono-guanidine compound. The polymer is preferably Mono-guanidine compound as a (possibly diluted) liquid, ie in liquid form. The polymeric mono-guanidine compound is preferably 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 made up to 100 g with the liquid. An aqueous solution of the polymeric mono-guanidine compound is particularly preferably used as the treatment liquid in step b). The liquid can also contain other additives, for example release agents and / or quaternary ammonium compounds.

In step b) of the process according to the invention, the polymeric mono-guanidine compound is preferably used as part of a liquid composition and / or in a liquid in a concentration of 10 to 85% by weight, particularly preferably 20 to 70% by weight and particularly preferably from 25 to 55% by weight, based on the total weight of the liquid. In particular, the liquid is an aqueous solution of the polymeric mono-guanidine compound, which can also contain other additives. The concentration by mass of the polymeric mono-guanidine compound given here in “% by weight” or “% by weight” is understood. This means that the mass of the polymeric mono-guanidine compound is based on the total mass of the liquid.

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

The preferred amount of the polymeric mono-guanidine compound which is applied in step b) is 2 to 200 g / m ² , particularly preferably 4 to 80 g / m ² and particularly preferably 6 to 30 g / m ² , based on the surface of the fiber mat treated in step b). Treated surface means, for example, the total surface of the top surface, even if parts of it are left out, but not the total sum of all surfaces of the fiber mat, ie the top surface, the bottom surface and the edge surfaces. According to one embodiment, the polymeric mono-guanidine compound is distributed uniformly over the surface of the top and / or the bottom. When using dilute preparations which contain the polymeric mono-guanidine compound, the above g / m ² data relate to g of pure polymeric mono-guanidine compound per m ^{2 of} treated surface. If, for example in step b) 50 g of a 50% by weight solution of the polymeric mono-guanidine compound is sprayed onto a surface of 1 m ² , the amount of polymeric mono-guanidine compound as used here is 25 g / m ² .

In a preferred embodiment of the invention, the polymeric mono-guanidine compound is PHMG, its salt and / or a mixture thereof. PHMG is particularly preferred, in particular PHMG * HCl.

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

It has been shown that the treatment of at least one of the surfaces of the fiber mat in step b) of the method according to the invention can be integrated in a simple and inexpensive manner into already conventional production processes for the production of fiberboard. The fiber mat can be provided by sprinkling glued fibers onto a forming belt. Usually, one of the two surfaces of the fiber mat 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 from step b) can be carried out on the top side and / or on the bottom side lying on the molding tape.

The treatment in step b) with the polymeric mono-guanidine compound or the liquid containing polymeric mono-guanidine compound can be carried out, for example, by brushing on or spraying on. Preferably treatment is by spraying, e.g. using a blowline. The treatment can furthermore be carried out by first introducing the polymeric mono-guanidine compound from step b) and then providing and applying the fiber mat from step a). The presentation can e.g. done by spraying. However, it is also possible that the fiber mat from step a) is first 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, the fiber mat is first provided on a shaping belt and then the surface of the fiber mat facing upward is treated with the polymeric mono-guanidine compound from step b). Preferably, the polymeric mono-guanidine compound or the liquid containing it is sprayed on.

In another embodiment, the polymeric mono-guanidine compound or the liquid containing it is initially placed on the forming belt and then the fiber mat is provided. The polymeric mono-guanidine compound or the liquid containing it is preferably introduced by spraying. In a special embodiment, the surface facing upward is additionally treated with the polymeric mono-guanidine compound or the liquid containing it. As a result, a fiber mat or fiberboard that has been treated on both surfaces can be obtained.

In a further embodiment, preferably in a continuous process for the production of fiberboard, both surfaces of the fiber mat are treated with the polymeric mono-guanidine compound, the underside being treated first. The treatment time of the bottom 1 up to 40 seconds, preferably 2 to 30 seconds and in particular 2 to 20 seconds before the treatment of the top 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 is preferably carried out after the fiber mat has been formed and / or shortly before the fiber mat is pressed into a fiber board.

The contact time or the time between treatment with the polymeric mono-guanidine compound in step b) and pressing in step c) can in principle be varied. In one embodiment, the time between treatment with the polymeric mono-guanidine compound in step b) and pressing in step c) is at least 1, 2, 5, 10 or 15 seconds. The upper limit for the time between treatment with the polymeric mono-guanidine compound in step b) and pressing in step c) can be 5 minutes, 2 minutes, 40 seconds, 30 seconds or 20 seconds, the lower and Upper limits can be combined. The time between treatment with the polymeric mono-guanidine compound in step b) and pressing in step c) is preferably 1 to 40 seconds, particularly preferably 2 to 30 seconds and particularly preferably 2 to 20 seconds.

Furthermore, it is provided in the method according to the invention that in step c) the surface-treated fiber mat obtained from step b) is pressed to form a fiberboard.

In principle, various methods are known to the person skilled in the art for pressing glued lignocellulose-containing fibers into a fiberboard. Step c) is preferably a hot pressing. Suitable temperatures for pressing in step c) of the process according to the invention or one of its embodiments are temperatures from 150 ° C. to 250 ° C., preferably from 160 ° C. to 240 ° C., particularly preferably from 180 ° C. to 230 ° C. At temperatures in these Areas, the process can be carried out particularly economically. Optimal results can be achieved if the pressing is carried out at a pressing temperature of at least about 150 ° C.

The press 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 here means in particular the dwell 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 proven 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 particularly good adhesion of the lignocellulose-containing fibers to one another. In addition, a high strength of the lignocellulose-containing fiberboard can be achieved with such a pressing pressure.

The invention also provides fiberboard that can be obtained by the process described above.

Another object of the invention is a roof or wall component, in particular one for house construction. 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 is concentrated in the area of the surface, which, in relation to the building of the house, points inwards. The fiberboard is therefore preferably oriented within the roof or wall component in such a way that the internal surface, based on the house construction, belongs to the area in which the at least one polymeric mono-guanidine compound is concentrated.

The fiberboard can, for example, have been produced by the method according to the invention or one of its embodiments. The fiberboard is preferably a DHF board with two different surfaces. In this case, the inner surface of the DHF plate, based on the house construction, was preferably treated with a polymeric mono-guanidine compound in step b).

As described above, the polymeric mono-guanidine compound is compatible with the manufacturing process and fiberboard manufacturing conditions. In particular, it does not appear to react with components of the fiberboard that could lead to undesirable discoloration of the product. By using the polymeric mono-guanidine compound, undesirable discoloration of the product is largely avoided.

Thus, according to the invention, a product with a uniform coloring of the surface can be obtained. If both surfaces of the fiberboard or 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 untreated surface of the fiberboard or 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 relates generally to the use of a polymeric mono-guanidine compound in the manufacture of fiberboard to increase the resistance of the fiberboard to fungal attack. The above statements regarding the fiberboard according to the invention and the method according to the invention apply accordingly to the use according to the invention.

Polymeric mono-guanidine compounds have not previously been known as a biocide in fiberboard manufacture. Their possible use in the manufacture of fiberboard was surprising for the person skilled in the art. This is especially true against the background that wood or fiberboard is attacked by another spectrum of microorganisms, in particular fungi, whereas the polymeric mono-guanidine compounds in their previous use have been used primarily against bacteria.

If here or elsewhere we speak of "fungus" or "fungal infestation", then "fungus" means the broad definition for the realm of the "fungi" from biological taxonomy. In addition to unicellular organisms such as baker's yeast, this also includes multicellular organisms such as molds or stand fungi. "Fungus" here means above all wood-destroying and / or wood-discoloring fungi or the infestation by them. These wood-destroying and / or wood-discoloring fungi typically damage the wood by, for example, brown rot, white rot, mold rot, mold, blueness or red streaking. According to one embodiment, the fungi are molds and / or blue stains. The fungi can also be selected from the Basomycetes, Ascomycetes and Deutomycetes. By "increasing resistance" as used here is meant a reduction in fungal attack compared to a non-biocidal, fungicidal and / or fungistatic 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 Effect of Microorganisms on Plastics" as described in the exemplary embodiments.

In particular, the invention also provides for the use of a polymeric mono-guanidine compound in the surface treatment of a fiber mat in the manufacture of fiberboard to increase the resistance of the fiberboard to fungal attack, in particular the use in the inventive method described above. Particularly good results are obtained when PHMG, a salt thereof or a mixture thereof is used.

Figur 1

zeigt eine Faserplatte 1, die nach dem erfindungsgemäßen Verfahren 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 jeweils mit einer polymeren Mono-Guanidin-Verbindung in Schritt b) des erfindungsgemäßen Verfahrens behandelt wurden. Die Bereiche 2' und 3' skizzieren die oberflächlichen Schichten der beiden Hauptseiten, deren Beständigkeit gegenüber Pilzbefall durch die Behandlung mit der polymeren Mono-Guanidin-Verbindung erhöht wurde. In diesen Bereichen 2' und 3' ist die mindestens eine polymere Mono-Guanidin-Verbindung konzentriert. Der Kern der Faserplatte bleibt frei von der polymeren Mono-Guanidin-Verbindung. Die verbleibenden Flächen 4 stellen die Kanten der Faserplatte 1 dar.

Figur 2a

zeigt schematisch die Herstellung einer Faserplatte 1' nach einer Ausführungsform des erfindungsgemäßen Verfahrens, bei der eine der beiden Hauptseiten mit einer polymeren Mono-Guanidin-Verbindung in Schritt b) behandelt wird. Auf eine Fasermatte 5, die im Wesentlichen aus mit Bindemitteln beleimten lignocellulosehaltige Fasern besteht, wird eine Flüssigkeit 6 enthaltend eine polymere Mono-Guanidin-Verbindung 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 polymeren Mono-Guanidin-Verbindung behandelt wurden, nach oben orientiert dargestellt. In dem Bereich 2' ist mindestens eine polymere Mono-Guanidin-Verbindung konzentriert.

Figur 2b

zeigt schematisch die Herstellung einer Faserplatte 1" nach einer Ausführungsform des erfindungsgemäßen Verfahrens, bei der beide Hauptseiten, d.h. die Oberseite 2 und die Unterseite 3, mit einer polymeren Mono-Guanidin-Verbindung in Schritt b) behandelt wurden. Eine Flüssigkeit 6 enthaltend eine polymere Mono-Guanidin-Verbindung 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 polymeren Mono-Guanidin-Verbindung behandelt wurde, nach oben und die Unterseite 3 (bzw. die Deckschicht 3") nach unten orientiert dargestellt. In dem Bereich 2" und 3" ist mindestens eine polymere Mono-Guanidin-Verbindung konzentriert.

Particular embodiments of the invention are explained below by way of example using figures. One by the method according to the invention available fiberboard is for example in Figure 1 shown. Embodiments of the method according to the invention are shown schematically in FIGS Figures 2a and 2 B shown.

Figure 1

shows a fiberboard 1, which was produced by the inventive method. The fiberboard 1 has two main sides 2 and 3, one forming the top 2 and the other the bottom 3 of the fiberboard 1, each of which was treated with a polymeric mono-guanidine compound in step b) of the process according to the invention. The areas 2 'and 3' outline the superficial layers of the two main sides, the resistance to fungal attack was increased by the treatment with the polymeric mono-guanidine compound. The at least one polymeric mono-guanidine compound is concentrated in these regions 2 'and 3'. The core of the fiberboard remains free of the polymeric mono-guanidine compound. The remaining surfaces 4 represent the edges of the fiberboard 1.

Figure 2a

shows schematically the production of a fiberboard 1 'according to an 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). A liquid 6 containing a polymeric mono-guanidine compound is sprayed from above onto a fiber mat 5, which essentially consists of lignocellulose-containing fibers glued with binders. Thereafter, the treated fiber mat 5 is pressed in a hot press 7 under the action of increased pressure and increased temperature to the fiber board 1 '. In the fiberboard 1 ', which is shown following the hot press 7, the top 2 and the treated cover layer 2', which have been treated with the polymeric mono-guanidine compound, are shown facing upwards. At least one polymeric mono-guanidine compound is concentrated in the region 2 '.

Figure 2b

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 top 2 and the bottom 3, were treated with a polymeric mono-guanidine compound in step b). A liquid 6 containing a polymer Mono-guanidine compound is applied by spraying onto a shaping belt 8. A fiber mat 5, which consists essentially of lignocellulose-containing fibers glued with binders, is then provided on this presented liquid 6. The liquid 6 is then applied to the upward-facing surface of the The fiber mat 5 is sprayed on from above. Finally, the fiber mat 5 treated from both main sides is pressed to the fiber board 1 "in a hot press 7 under the action of increased pressure and temperature. In the fiberboard 1 ", which is shown following the hot press 7, the top 2 (or the top layer 2") that has been treated with the polymeric mono-guanidine compound is on the top and the bottom 3 (or the top layer 3 ") is shown oriented downwards. At least one polymeric mono-guanidine compound is concentrated in the region 2" and 3 ".

The invention is described in more detail below using exemplary embodiments.

Example 1 : Production of fiberboard

In this example, a reference board was produced using an MDF process common in the wood industry. The test panels 1 and 2 were produced in accordance with one embodiment of the invention, ie by treating both surfaces of the fiber mat with a polymeric mono-guanidine compound.

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)
• Board thickness: 8 mm
• Board density: 600 kg / m ³
• Press temperature: 200 ° C
• Press factor: 10 sec / mm

2. Production of the reference plate:

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

3. Production of test panels 1 and 2:

The test panels 1 and 2 were produced in duplicate according to one embodiment of the method according to the invention. This gave fiberboard, the two main sides of which had been treated with PHMG during manufacture.

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

In the manufacture of test panels 1 and 2, the glued fiber mats were additionally surface-treated with PHMG (25% solution of PHMG * HCl in water) as part of the fiber mat shaping and shortly before the press entered. The surface treatment was carried out in the order given below:

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

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

3. Composition of the reference plate and the test plates:

The composition of the reference plate and the test plates is summarized in Table 1. <b> tab. 1 </b> Composition of the fiberboard Treatment with PHMG (amount of PHMG [g / m ² ]) eMDI (w / atro fibers) Reference plate No 3% Test panel 1 Yes (48 g / m ² ) 3% Test panel 2 Yes (24 g / m ² ) 3%

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

Source test according to EN 317 (average of 5 individual tests)

• Reference plate: 10.1%
• Test panel 1: 11.0%
• Test plate 2: 10.1%

The results show that treatment with PHMG did not have a negative effect on swelling. Test plate 2 showed the same swelling as the reference plate. Test 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
• Test plate 1: 0.49 N / m ²
• Test plate 2: 0.48 N / m ²

The results show that the good mechanical properties were retained despite the additional treatment with PHMG. Test panels 1 and 2 even showed a slightly higher strength than the reference panel. In particular, test plate 2 showed approximately the same mechanical properties as test plate 1. This was surprising since test plate 1 had a slightly higher swelling, which is why the skilled worker would have expected a decrease in tensile strength.

When comparing the color of the reference plate and test plates 1 and 2, it was found that test plates 1 and 2 showed no discoloration in comparison to the reference plate.

Example 2: Determination of the 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 Effect of Microorganisms on Plastics".

To test the resistance to fungal attack, test specimens of the reference plate and test plate 1 from Example 1 were incubated for 4 weeks with a test organism on different nutrient media (see point 3, tests A, B and B '). After the incubation period, the growth of the test specimens became visual assessed to determine fungal growth (test A) or fungistatic activity (test B, B ') (see point 4, evaluation).

1. Equipment and test equipment:

Test specimen: After one-week air conditioning (20 ° C, 65% RH) of the reference plate and test plate 1 from Example 1, nine test specimens measuring 5 x 5 x 0.8 cm were cut out. Test organism: Penicillum sp. Stock mineral salt solution: 2 g NaNO ₃ 0.7 g 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 tap water (pH 6 - 6.5) About 0.1 g of Tween 80 was added to 1 L of stock mineral salt solution, the solution was then sterilized.

2. Cultivation of stock culture and solutions:

The test organism was first pre-cultivated on malt extract agar plates. After the agar surfaces were completely overgrown, the fungal spores were harvested using the mineral salt solution with the aid of a Drigalski spatula.

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

This solution was then filtered through an extraction tube with cotton (sterile). The number of bacteria was determined with the Thomas Chamber. The final bacterial count was a CFU of 4 x 10 ⁷ / ml. This solution was diluted with mineral salt solution to a density of 10 ⁶ CFU / ml and the spore suspension for the experiments was obtained.

200 ul 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 the nutrient media for the experiments A. B and B ' 3.1.1. Incomplete agar medium for experiment A:

So much agar was added to the stock mineral salt solution 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 closed with a lid, which was provided with a cotton plug in the middle, and steam-sterilized.

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

To prepare the complete agar, the incomplete agar from point 3.1.1. provided 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 closed with a lid, which was provided with a cotton plug in the middle, and steam-sterilized.

3.2 Description and implementation of experiment A: Fungus growth test

In test A, the test specimens were applied to the incomplete agar (see item 3.1.1.), Which had previously been inoculated with a spore suspension of the test organism. If the test specimen contains no components that can be used by the fungi, the fungi cannot develop a mycelium and overgrow the test specimen or attack the test specimens through their metabolic products. Experiment A is suitable for to assess the basic resistance of the test specimens against fungal attack in the absence of organic contaminants.

Execution:

Three test specimens each of the reference plate and test plate 1 from Example 1 were used. The incomplete agar from point 3.1.1. inoculated with 200 µl of the spore suspension from point 2. The respective test body was applied directly to the agar and incubated at 24 ° C / 90% RH for 4 weeks.

3.3 Description and performance of tests B and B ': fungistatic activity

In experiments B and B ', the test bodies were applied to the complete agar (see item 3.1.2.), Which had been inoculated with a spore suspension of the test organism beforehand. Experiments B and B 'are suitable for assessing the basic fungistatic activity 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. An inhibition of growth on the test body or on the culture medium (inhibition zone) indicates a fungicidal or fungistatic activity or equipment of the test body.

Execution:

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

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

In experiment B ', the entire agar was first incubated until its surface was completely covered with the test organism. The respective test specimen was then applied to the complete agar and incubated at 24 ° C./90% RH for 4 weeks.

4. Evaluation of experiments A. B and B ':

The incubated test specimens from experiments A, B and B 'were evaluated visually. The results are summarized in Table 2. Tab. 2 Overview of the evaluation of tests A, B and B '. Strong growth on the surface (++); medium (+), the main sides and edges were covered; medium (+/-), whereby only the edges were covered; no fouling (-). Test specimen Test specimen no. eMDI (w / atro fibers) Visual assessment experiment A Visual assessment experiment B Visual assessment experiment B ' Reference plate R-1 3% + ⁺ ++ - Reference plate R-2 3% + + ++ Reference plate R-3 3% - ++ - Test panel 1 V-1 3% - - - Test panel 1 V-2 3% - - - Test panel 1 V-3 3% +/- - -

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

In the test specimens of the reference plate, there was predominantly a strong to medium fungal growth. In the test specimens, which were rated "medium", the fungal growth extended to the surface of the main side pointing upwards and to the edges of the respective test specimen.

With the test specimens of the test plate, there was mainly no to medium fungal growth in all tests. In the test specimen, which was rated "medium", the fungal growth only extended to the edges of the respective test specimen. The area of the upward-facing main page that had been treated with PHMG was not overgrown.

If you compare the reference plate with test plate 1, the surface treatment with PHMG already shows a significant reduction in fungal growth.

Claims (21)

1. Fibreboard produced by pressing lignocellulose-containing fibres contacted with binder in a method which comprises the following steps:

   a) providing a fibre mat containing bonded, lignocellulose-containing fibres,

   b) treating at least one of the two surfaces of the fibre mat from step a) with a polymeric monoguanidine compound,

   c) pressing the surface-treated fibre mat obtained from step b) into a fibreboard,

   wherein

   - at least one polymeric monoguanidine compound is concentrated in the area of at least one of the two surfaces of the fibreboard;

   - a concentration gradient of polymeric monoguanidine compound exists between at least one surface of the fibreboard and its centre and the fibreboard has an area in its core, in which the concentration of the polymeric monoguanidine compound is lower than in the area of the surface of the fibreboard.
2. Fibreboard according to claim 1, characterised in that the polymeric monoguanidine compound is selected from the group consisting of a polymeric monoguanidine compound, its salt and a mixture thereof.
3. Fibreboard according to claim 1 or 2, characterised in that the polymeric monoguanidine compound is polyhexamethylene guanidine (PHMG).
4. Fibreboard according to any one of claims 1 to 3, characterised in that the area of at least one of the two surfaces of the fibreboard, in which the polymeric monoguanidine compound is concentrated, extends starting from the surface of the fibreboard at least 0.01, 0.05, 0.1, 0.5, 1, 2, 3 or 5 mm into the interior of the fibreboard.
5. Fibreboard according to any one of claims 1 to 4, characterised in that the fibreboard has an area in its core which contains less than 0.3, 0.1, 0.05 or 0.01 wt.-% in relation to the dry mass (atro) of the lignocellulose-containing material and particularly preferably contains no polymeric monoguanidine compound in its core.
6. Fibreboard according to any one of claims 1 to 5, characterised in that the fibreboard in the area of at least one of the two surfaces of the fibreboard has the polymeric monoguanidine compound in a surface concentration of 2 to 200 g/m², preferably of 4 to 80 g/m² and particularly preferably of 6 to 30 g/m² in relation to the respective surface of the fibreboard.
7. Fibreboard according to any one of claims 1 to 6, characterised in that the fibreboard has a bulk density of 500 to 700 kg/m³, preferably 550 to 650 kg/m³ and particularly preferably 580 to 625 kg/m³ and/or has a thickness of 6 to 30 mm, preferably 10 to 22 mm and particularly preferably 12 to 20 mm.
8. Fibreboard according to any one of claims 1 to 7, characterised in that the fibreboard is a DHF, UDF, LDF, MDF or HDF board.
9. Fibreboard according to any one of claims 1 to 8, characterised in that the lignocellulose-containing fibres are wood fibres.
10. Method for producing a fibreboard according to any one of claims 1 to 9, comprising the following steps:

    a) providing a fibre mat containing bonded, lignocellulose-containing fibres,

    b) treating at least one of the two surfaces of the fibre mat from step a) with a polymeric monoguanidine compound,

    c) pressing the surface-treated fibre mat obtained from step b) into a fibreboard,

    wherein a fibreboard is produced according to any one of claims 1 to 9.
11. Method according to claim 10, characterised in that the polymeric monoguanidine compound used in step b) is used in a liquid in a concentration of 10 to 85 wt.-%, preferably of 20 to 70 wt.-% and particularly preferably of 25 to 55 wt.-% in relation to the total weight of the liquid.
12. Method according to either of claims 10 and 11, characterised in that the amount of the monoguanidine compound applied in the treatment in step b) is 2 to 200 g/m², preferably 4 to 80 g/m² and particularly preferably 6 to 30 g/m² in relation to the surface of the fibreboard treated in step b).
13. Method according to any one of claims 10 to 12, characterised in that the treatment in step b) is effected by spraying on the polymeric monoguanidine compound or the liquid which contains the polymeric monoguanidine compound.
14. Method according to any one of claims 10 to 13, characterised in that the period of time between the treatment with the polymeric monoguanidine compound in step b) and the pressing in step c) is 1 to 40 seconds, preferably 2 to 30 seconds and particularly preferably 2 to 20 seconds.
15. Method according to any one of Claims 10 to 14, characterised in that the bonded lignocellulose-containing fibres provided in step a) were bonded using an isocyanate-based binder, in particular a PMDI-based binder.
16. Method according to any one of claims 10 to 15, characterised in that in step b) both surfaces of the fibre mat are treated.
17. Method according to any one of claims 10 to 16, 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, particularly preferably of 180 °C to 230 °C and/or with a pressing factor of 2 to 15 s/mm, preferably 2 to 12 s/mm and particularly preferably 4 to 12 s/mm.
18. Roof or wall component containing or consisting of the fibreboard according to any one of claims 1 to 9.
19. Roof or wall component according to claim 18, wherein the fibreboard is a DHF board with two different surfaces, characterised in that in the surface of the DHF board lying on the inside in relation to the house construction, at least one polymeric monoguanidine compound is concentrated in the area of at least one of the two surfaces of the DHF board.
20. Use of a polymeric monoguanidine compound in fibreboard manufacture for increasing the resistance of the fibreboard according to any one of claims 1 to 9 against fungal infestation.
21. Use of a polymeric monoguanidine compound according to claim 20, characterised in that the polymeric monoguanidine compound is used in the surface treatment of a fibre mat in fibreboard manufacture to increase the resistance of the fibreboard against fungal infestation.

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