Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
  • B27K—PROCESSES, APPARATUS OR SELECTION OF SUBSTANCES FOR IMPREGNATING, STAINING, DYEING, BLEACHING OF WOOD OR SIMILAR MATERIALS, OR TREATING OF WOOD OR SIMILAR MATERIALS WITH PERMEANT LIQUIDS, NOT OTHERWISE PROVIDED FOR; CHEMICAL OR PHYSICAL TREATMENT OF CORK, CANE, REED, STRAW OR SIMILAR MATERIALS
  • B27K3/00—Impregnating wood, e.g. impregnation pretreatment, for example puncturing; Wood impregnation aids not directly involved in the impregnation process
  • B27K3/52—Impregnating agents containing mixtures of inorganic and organic compounds
• • A—HUMAN NECESSITIES
  • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
  • A01N—PRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF; BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES OR AS HERBICIDES; PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS
  • A01N25/00—Biocides, pest repellants or attractants, or plant growth regulators, characterised by their forms, or by their non-active ingredients or by their methods of application, e.g. seed treatment or sequential application; Substances for reducing the noxious effect of the active ingredients to organisms other than pests
  • A01N25/32—Ingredients for reducing the noxious effect of the active substances to organisms other than pests, e.g. toxicity reducing compositions, self-destructing compositions
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
  • B27K—PROCESSES, APPARATUS OR SELECTION OF SUBSTANCES FOR IMPREGNATING, STAINING, DYEING, BLEACHING OF WOOD OR SIMILAR MATERIALS, OR TREATING OF WOOD OR SIMILAR MATERIALS WITH PERMEANT LIQUIDS, NOT OTHERWISE PROVIDED FOR; CHEMICAL OR PHYSICAL TREATMENT OF CORK, CANE, REED, STRAW OR SIMILAR MATERIALS
  • B27K3/00—Impregnating wood, e.g. impregnation pretreatment, for example puncturing; Wood impregnation aids not directly involved in the impregnation process
  • B27K3/02—Processes; Apparatus
  • B27K3/0278—Processes; Apparatus involving an additional treatment during or after impregnation
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
  • B27K—PROCESSES, APPARATUS OR SELECTION OF SUBSTANCES FOR IMPREGNATING, STAINING, DYEING, BLEACHING OF WOOD OR SIMILAR MATERIALS, OR TREATING OF WOOD OR SIMILAR MATERIALS WITH PERMEANT LIQUIDS, NOT OTHERWISE PROVIDED FOR; CHEMICAL OR PHYSICAL TREATMENT OF CORK, CANE, REED, STRAW OR SIMILAR MATERIALS
  • B27K3/00—Impregnating wood, e.g. impregnation pretreatment, for example puncturing; Wood impregnation aids not directly involved in the impregnation process
  • B27K3/16—Inorganic impregnating agents
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
  • B27K—PROCESSES, APPARATUS OR SELECTION OF SUBSTANCES FOR IMPREGNATING, STAINING, DYEING, BLEACHING OF WOOD OR SIMILAR MATERIALS, OR TREATING OF WOOD OR SIMILAR MATERIALS WITH PERMEANT LIQUIDS, NOT OTHERWISE PROVIDED FOR; CHEMICAL OR PHYSICAL TREATMENT OF CORK, CANE, REED, STRAW OR SIMILAR MATERIALS
  • B27K5/00—Treating of wood not provided for in groups B27K1/00, B27K3/00
  • B27K5/003—Treating of wood not provided for in groups B27K1/00, B27K3/00 by using electromagnetic radiation or mechanical waves
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B27—WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; NAILING OR STAPLING MACHINES IN GENERAL
  • B27K—PROCESSES, APPARATUS OR SELECTION OF SUBSTANCES FOR IMPREGNATING, STAINING, DYEING, BLEACHING OF WOOD OR SIMILAR MATERIALS, OR TREATING OF WOOD OR SIMILAR MATERIALS WITH PERMEANT LIQUIDS, NOT OTHERWISE PROVIDED FOR; CHEMICAL OR PHYSICAL TREATMENT OF CORK, CANE, REED, STRAW OR SIMILAR MATERIALS
  • B27K2240/00—Purpose of the treatment
  • B27K2240/15—Decontamination of previously treated wood
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/4935—Impregnated naturally solid product [e.g., leather, stone, etc.]
  • Y10T428/662—Wood timber product [e.g., piling, post, veneer, etc.]

Definitions

• Wood treatment agent and method for treating wood. Wood materials or the like
• the invention relates to a wood treatment agent according to the preamble of patent claim 1 and to a method for treating wood, wood materials or the like according to the preamble of claim 7. Finally, the invention also relates to wood, a wood material or the like according to the preamble of claim 10 and to a use of photocatalysts for decomposing organic substances, organic compounds and / or biocides according to claim 13.
• wood, wood-based materials or the like The chemical protection of wood, wood-based materials or the like is achieved by means of biocide-containing wood preservatives. These agents are applied to the wood or introduced into the wood and build there a very durable biocide barrier against wood-destroying fungi and insects. Wood, wood-based materials or the like may further contain organic substances and / or organic compounds.
• a wood preservative in the wood for example, via so-called surface processes, such as painting, dipping, spraying, via storage methods, such as a tray impregnation, or via impregnation methods, such as, for example, a pressure impregnation of a boiler. All these methods have in common that the wood preservative passes through the wood surface into the interior of the wood and, depending on the chosen method, leaves behind or builds up a more or less deep, biocide-loaded barrier zone and / or a barrier zone, which is produced by organic Substances and / or organic compounds is loaded.
• the distribution of organic substances and / or organic compounds and / or biocides, hereinafter also referred to as aforementioned substances, is approximately homogeneous within this blocking zone only in the case of the aforementioned impregnation method.
• the content of the aforementioned substances also called active ingredient content, usually decreases exponentially from the surface to the inside.
• the depth of penetration of the wood preservative is usually about 1 to 5 mm, the efficacy depth, referred to above exclusion zone, 0.5 to 3 mm, the distribution of the aforementioned substances, in particular the biocide distribution, in the exclusion zone from the surface decreases strongly exponentially inside.
• the depth of penetration of the wood preservative is usually about 5 to 15 mm, the efficacy depth 3 to 12 mm, the distribution of the aforementioned substances, in particular the biocide distribution decreases moderately exponential in the exclusion zone from the surface to the inside.
• the penetration depth of the wood preservative is usually more than 20 mm, the effectiveness depth also more than 20 mm, the distribution of the aforementioned substances, in particular the biocide distribution, in the exclusion zone is almost homogeneous.
• very high concentrations of the abovementioned substances occur on and immediately below the treated surface of the wood, wood-based material or the like.
• the concentration gradient between the wood surface and the immediate environment causes a mass transfer from the wood into the surrounding air or to the suspended particles contained in the air.
• the desorption of biocide molecules on dust particles can lead to an additional biocide contamination of the room air in closed rooms.
• the invention has for its object to design a wood treatment agent of the type mentioned above and a method of the type mentioned above so that the delivery of organic substances, organic compounds and / or biocide release from wood, wood-based materials or the like in the immediate vicinity, in particular in living spaces, is reduced to a negligible level. Furthermore, a wood, wood-based material or the like of the aforementioned type is to be created, the surface of which reduces exposure to organic substances, organic compounds and / or biocide exposure in direct contact with humans and animals to a technically feasible minimum.
• the wood treatment agent according to the invention contains a wood preservative containing at least one organic substance, an organic compound and / or at least one biocide, wherein the at least one organic substance, organic compound and / or the at least one biocide is photocatalytically degradable. Furthermore, the wood treatment agent contains at least one photocatalyst, which causes the degradation of the at least one organic substance, organic compound and / or the at least one biocide. This makes it possible to eliminate residues on one or more of the aforementioned substances, in particular biocide residues, on treated wood surfaces by means of a photoinduced or photocatalytic destruction.
• the at least one photocatalyst contains or contains, for example, titanium dioxide (T1O2), carbon-doped TiO 2 , nitrogen-doped TiO 2 or nitrogen-doped TIO 2 with palladium nanoparticles.
• the TiO 2 is in anatase configuration.
• the different, aforementioned dopants of the T1O2 cause the photocatalysis takes place already in the daylight range and not exclusively in the ultraviolet (UV) range.
• the aforementioned palladium nanoparticles like a kind of "battery", cause an energy store, so that the photocatalysis can continue to progress even in poor light conditions and / or even in the dark.
• the at least one photocatalyst is suspended in the wood preservative, the particle size of the at least one photocatalyst being 10 to 30 ⁇ 10 3 nm, preferably 100 to 5 ⁇ 10 3 nm, particularly preferably 150 to 3 ⁇ 10 3 nm, and the proportion of the foundeds- least a photocatalyst in wood preservatives 1 x 10 "to 10 wt .-%, preferably 0.5 to 5 wt .-%, particularly preferably 1 to 3 wt .-%, is.
• the particle size of the at least one photocatalyst can be selected so that the photocatalyst is almost exclusively on the surface of the wood, wood-based material or the like and penetrates only slightly into the wood.
• the photocatalyst can be provided precisely there and largely only where an incidence of light can be assumed or presupposed.
• the at least one biocide is one or more fungicides selected from
• the aforementioned photocatalysts are able to break down a wide variety of fungicides and insecticides, so that these substances can not get out of the wood in the immediate vicinity.
• Analogous embodiments apply to the degradation of one or more organic substances and / or compounds.
• a wood preservative containing at least one organic substance, an organic compound and / or at least one biocide, on applied to the wood and / or introduced into this furthermore comprises the further steps of applying / introducing at least one photocatalyst on or into the wood, which causes the degradation of the at least one organic substance, organic compound and / or of the at least one biocide, wherein / Introducing the at least one photocatalyst carried out together with or after the installation / introduction of the wood preservative.
• the first, above-mentioned alternative, in which the at least one photocatalyst is applied or introduced together with the wood preservative on the wood or in the wood, has the advantage that the at least one photocatalyst not in a separate step, but simultaneously with the wood preservative can be supplied to the wood. So it's a separate, i. separate application or application or introduction of the at least one photocatalyst usually not required.
• the second aforementioned alternative, according to which the introduction / introduction of the at least one photocatalyst takes place after the wood preservative has been applied, has the advantage that wood which has already been treated with a wood preservative can to some extent subsequently be provided with the at least one photocatalyst , so that the inventive method can also be used in already provided with wood preservatives woods.
• the inventive method can also be used in older, already treated with a wood preservative woods.
• the at least one photocatalyst is suspended in the wood preservative and applied together with this on the wood and / or introduced into this. The wood preservative and the at least one photocatalyst can thus be fed to the wood in a single step.
• the method according to the invention can be carried out particularly inexpensively.
• the particle size of the at least one photocatalyst is 10 to 30 ⁇ 10 3 nm, preferably 100 to 5 ⁇ 10 3 nm, particularly preferably 150 to 3 ⁇ 10 3 nm, and the particle size is determined in such a way. chooses that the at least one photocatalyst applied to the wood at most penetrates into the wood up to about 1 mm.
• the at least one photocatalyst is located in a near-surface region of the wood, namely in the area in which light can occur during the life of the wood.
• the wood or the wood material or the like contains a wood preservative containing at least one organic substance, an organic compound and / or at least one biocide.
• the at least one organic substance, organic compound and / or the at least one biocide is photocatalytically degradable.
• the wood or the wood material or the like has at least one photocatalyst, which causes the degradation of the at least one organic substance, organic compound and / or the at least one biocide.
• the wood, the wood-based material or the like therefore also contains at least one photocatalyst in addition to the at least one organic substance, an organic compound and / or the wood preservative containing at least one biocide.
• the at least one photocatalyst is that which has already been mentioned above with respect to the wood preservative of the present invention. Also, the particle size and the selection of the particle size correspond to those details, as they were previously stated in the wood treatment agent.
• the invention also includes the aspect of photocatalysts for degradation of organic shear substances, organic compounds and / or biocides in at least one organic substance, an organic compound and / or at least one biocidal wood to use.
• Embodiments of the subject invention are described below with reference to the drawing, all described and / or illustrated features alone or in any combination form the subject matter of the present invention, regardless of their combination in the claims or their dependency. Show it:
• Fig. 1 is a schematic representation of photocatalysis on a photocatalyst
• Fig. 2 is a schematic diagram in which the pigment content above the
• Penetration depth of the photocatalyst is plotted in the wood, this graph refers to a particle size of the photocatalyst between 20 and 150 nm;
• Fig. 3 is a schematic diagram in which the pigment content over the
• this graph refers to a particle size of the photocatalyst between 120 and 300 nm.
• Fig. 4 is a schematic diagram in which the pigment content above the
• this graph refers to a particle size of the photocatalyst between 300 and 800 nm.
• the wood treatment agent contains a wood preservative. This contains at least one organic substance, an organic compound and / or at least one biocide. The at least one organic substance, an organic compound and / or the at least one biocide is photocatalytically degradable. Furthermore, the wood treatment agent contains at least one photocatalyst 1 which is heated under suitable conditions, namely under light, the degradation of the at least one organic substance, an organic compound and / or the at least one biocide causes.
• the at least one photocatalyst 1 is or contains titanium dioxide ( ⁇ 2 ), carbon-doped TiO 2 , nitrogen-doped TiO 2 or nitrogen-doped TiO 2 with palladium nanoparticles.
• inorganic photocatalysts are or include ZnO, WO 3 , SnO 2 , Fe 2 O 3 , FeOOH, Al 2 O 3 , Si, SiO 2 , ZrO 2 , M0O 3, CdS.
• organic photocatalysts are or include indanthrone, phthalocyanines and their metal complexes, quinacridone and / or perylenetetracarboxylic anhydride, alone or in combination with TiO 2 .
• organic photoinitiators are or include benzil dimethyl ketal, the cyclohexyl phenyl ketone class and / or the acyl phosphine oxide class.
• the at least one photocatalyst is capable of collecting light energy, then into biocide molecules and, if present, also in residues of organic substances and / or organic compounds, e.g. in solvent residues initiate and destroy them with it.
• Solvent residues can be, for example, glycols, amino alcohols and / or glycol ethers.
• the at least one photocatalyst is suspended in the wood preservative according to a particularly preferred embodiment.
• the particle size of the at least one photocatalyst is 10 to 30 ⁇ 10 3 nm, preferably 100 to 5 ⁇ 10 3 nm, particularly preferably 150 to 3 ⁇ 10 3 nm.
• the particle size is also called pigment size.
• the proportion of the at least one photocatalyst in the wood preservative is 1 ⁇ 10 -4 to 10 wt .-%, preferably 0.5 to 5 wt .-%, particularly preferably 1 to 3 wt .-%. In founded, the proportion of at least one catalyst in wood preservative, the pigment content of the photoca talysators in wood preservative.
• the at least one biocide contains one or more fungicides and / or one or more insecticides.
• the one or more fungicides include, for example, triazoles, such as
• Azaconazole 1 - ([2- (2,4-dichlorophenyl) -1,3-dioxolan-2-yl] methyl) -1-H, 2,4-triazole, propiconazole: 1- [2- (2,4-) Dichlorophenyl) -4-propyl-1,3-dioxolan-2-yl] methyl-1-H-1,2,4-triazole,
• Tebuconazole 1-p-chlorophenyl-4,4-dimethyl-3 (1H-1,2,4-triazol-1-yl-methyl) -pentan-3-ol
• Cyproconazole 2- (4-chlorophenyl) -3-cyclopropyl-1- (1H, 2,4-triazol-1-yl) butan-2-ol, metconazole: 5 - [(4-chlorophenyl) methyl ⁇ 2, 2-dimethyl-1- (1H-1, 2,4-triazol-1-yl-methyl) cyclopentanol; Imidazole, like
• Thiazolcarboxanilide such as 2 ', 6, -Dibromo-2-methyl-4-trifluoromethoxy-4'-trifluoro- methyl-1, 3-thiazole-5-carboxanilide;
• Copper salts like Copper, sulphate, carbonate, hydroxide carbonate, dihydroxide, chloride, ammonia complexes, amine complexes, diazenium complexes, and copper, sulphate, carbonate, hydroxide carbonate, chloride as particles in micronised form (particle size of From 30 nm to 50 ⁇ m, preferably from 100 nm to 500 nm);
• Fenfuram furcarbanil, cyclafluramide, furmecyclox, Seedvax, Metsulfovax, pyrocarbolide, oxycarboxine, shirlan, mebenil (mepronil), benodanil, flutolanil (Moncut);
• Naphthalene derivatives such as
• Dichlorofluidide tolylfluanid, folpet, fluorfolpet; Captan, Captofol; Benzimidazoles, like
• Morpholine derivatives such as Tridemorph, fenpropimorph, falimorph, dimethomorph, dodemorph, aldimorph, fenpropidin and their arylsulfonic acid salts, such as.
• arylsulfonic acid salts such as toluenesulfonic acid and p-dodecylphenylsulfonic acid, iodine derivatives, such as
• Phenol derivatives such as
• 1-hydroxy-2-pyridinethione (and its Na, Fe, Mn, Zn salts), tetrachloro-4-methylsulfonylpyridine, pyrimethanil, mepanipyrim, dipyrrithione;
• Tributyltin oxide Cu 2 O, CuO, ZnO; Dialkyldithiocarbamates, such as
• Dial dithiocarbamates tetramethyl thiuram disulfide
• Dithiocarbamates Cufraneb, Ferbam, Mancopper, Mancozeb, Maneb, Metam, Metiram, Thiram, Zineb, Ziram;
• Formaldehyde and formaldehyde-releasing compounds such as
• Salts of sorbic acid such as Sodium sorbate, potassium sorbate.
• fungicides may be selected from one or more of the following:
• the one or more insecticides include, for example, phosphoric acid esters such as
• Organosilicon compounds preferably as Dimethyl (phenyl) silyl-methyl-3-phenoxybenzyl ethers such as dimethyl (4-ethoxyphenyl) silylmethyl-3-phenoxybenzyl ether or (dimethylphenyl) silyl-methyl-2-phenoxy-6-pyridylmethyl ether such as.
• dimethyl (9-ethoxy-phenyl) -silylmethyl-2-phenoxy-6-pyridylmethyl ether or [(phenyl) -3- (3-phenoxyphenyl) -propyl] (dimethyl) silanes such.
• Etofenprox fenpropathrin, fenfluthrin, fenvalerate, flucythrinate, flumethrin, fluvalinate, permethrin, pyrethrum, resmethrin and tralomethrin; Nitroimines and nitromethylenes, such as
• Chlorofluorazuron, diflubenzuron, flufenoxuron, flucycloxuron, hexaflumuron, penfluron, teflubenzuron, triflumuron and other development inhibitors such as benzoic acid [2-benzoyl-1- (1,1-dimethylethyl)] hydrazide, 2,6-dimethoxy- N - [5-] 4- (pentafluoroethoxy) -phenyl- [2,3,4-thiadiazol-2-yl] -benzamide, N-cyclopropyl-l, 3,5-triazine-2,4-triamine, 2- (4-phenoxyphenoxy) ethyl ethyl carbamate, 1- (decycloxy) -4- [(6-methoxy-4-hexynyl) oxy] benzene, (2-propynyl) -4-methoxybenzoate, fenoxycarb, pyriproxyfen,
• the at least one biocide can act as a fungicide or act as an insecticide or act as a fungicide and as an insecticide. Suitable mixtures of the substances mentioned above for the fungicides and insecticides may also be used.
• a wood preservative containing at least one organic substance, an organic compound and / or at least one biocide applied to the wood 2 and / or introduced into this.
• wood is used below as an abbreviation for the terms “wood, wood-based materials or the like”.
• the method includes the further steps of applying / introducing at least one photocatalyst on or into the wood, which causes the degradation of the at least one organic substance, organic compound and / or the at least one biocide, wherein the introduction / introduction of the at least a photocatalyst takes place together with or after the installation / introduction of the wood preservative.
• the at least one photocatalyst may be contacted with the wood at the same time as referred to above together with the wood preservative.
• the at least one photocatalyst according to a preferred embodiment of the invention is suspended in the wood preservative and applied together with this on the wood and / or introduced into this.
• the application / introduction of the at least one photocatalyst-containing wood preservative can be carried out in a single step.
• the at least one photocatalyst on time after the wood preservative on the wood or bring in the wood.
• wood which has already been treated with wood preservative can be aftertreated by applying the at least one photocatalyst in order to reduce the load of an organic substance, an organic compound and / or a biocide from the wood into the surrounding atmosphere, in particular into spaces such as Living spaces, decrease.
• the particle size of the at least one photocatalyst is 10 to 30 ⁇ 10 3 nm, preferably 100 to 5 ⁇ 10 3 nm, particularly preferably 150 to 3 ⁇ 10 3 nm, and is chosen such that the at least one photocat deposited on the wood is selected. lysator penetrates at most to about 1 mm into the wood. This will be explained in more detail below.
• the wood 2 thus contains a wood preservative containing at least one organic substance, an organic compound and / or at least one biocide.
• the aforementioned substances are photo-unstable.
• the wood 2 has a photocatalyst 1, which causes the degradation of the at least one organic substance, organic compound and / or the at least one biocide.
• the at least one photocatalyst 1 is or contains titanium dioxide (TiO 2 ), carbon-doped TiO 2 , nitrogen-doped ⁇ 2 or nitrogen-doped ⁇ 2 with palladium nanoparticles, in particular palladium in the form of metallic nanoparticles.
• the particle size of the at least one photocatalyst 1 in the wood is 10 to 30 ⁇ 10 3 nm, preferably 100 to 5 ⁇ 10 3 nm, particularly preferably 150 to 3 ⁇ 10 3 nm.
• the particle size, also called pigment size, is chosen such that the at least up to about 1 mm into the wood 2 from the surface 3 penetrates the wood applied at least photocatalyst.
• the invention also includes the use of photocatalysts for decomposing organic substances, organic compounds and / or biocides into at least one organic substance, an organic compound and / or at least one biocidal wood.
• the at least one photocatalyst When applying or applying the at least one photocatalyst individually or together with the wood preservative penetrates the liquid front together with the at least one organic substance, at least one organic compound and / or the at least one biocide in the wood.
• the at least one photocatalyst thus accumulates in an upper near-area and has a high concentration there.
• the penetration depth of the at least one photocatalyst corresponds approximately to the light penetration depth into the wood, namely preferably 0.5 to 1 mm.
• 80% of the at least one organic substance, organic compound and / or the at least one biocide are within a penetration depth of 2 to 3 mm on or in the wood.
• the near-surface region is heavily loaded with the at least one organic substance, at least one organic compound and / or the at least one biocide.
• FIG. 1 schematically shows the mode of action of photocatalysis on a photocatalyst pigment, namely a TiO 2 pigment.
• the electronic band structure of a semiconductor is characterized by the highest occupied energy band, called valence band V, and the lowest unoccupied energy band, called conduction band L.
• the aforementioned energy bands are separated by an energy gap.
• the semiconductor now absorbs 4 photons whose incident energy is greater than or equal to the energy gap, then electrons in the valence band V are excited to migrate into the conduction band. An excess of electrons is formed in conduction band L; in the valence band V corresponding electron holes are formed.
• These electron / hole pairs can recombine or react on the surface with electron donors or electron acceptors, as shown in FIG. 1 on the basis of adsorbed water and oxygen.
• the resulting radicals are highly reactive substances. They quickly attack surrounding substances, such as the abovementioned aforementioned substances, in particular biocides.
• the at least one photocatalyst applied to the wood can also have a disinfecting or sterilizing or preserving effect and / or cause near-surface self-cleaning.
• the semiconductor remains unchanged during the reaction.
• a direct oxidation or reduction of adsorbed on the semiconductor surface or immediately adjacent organic substances, organic compounds and / or biocides is possible.
• the photocatalytic degradation of organic substances, organic compounds and / or biocides can both reductively, for example by means of direct reduction by the electrons in the conduction band L, as well as oxidative way, for example by oxidation of the pollutant by OH radicals take place.
• the at least one organic substance and / or at least one organic compound and / or the at least one biocide is radically decomposed.
• the particle size of the at least one photocatalyst is selected such that the distribution of the photocatalyst in the wood sets in the desired manner.
• FIGS. 2 to 4 the pigment distribution of the photocatalyst in the wood 2 is shown schematically.
• the pigment content is plotted above the penetration depth, the surface 3 of the wood 2 being located on the left in the respective representation.
• the penetration depth of the photocatalyst thus increases from left to right.
• the particle size of the photocatalyst 20 to 150 nm In Fig. 2, the particle size of the photocatalyst 20 to 150 nm. It follows the curve 5 of the pigment distribution, as shown in the upper part of Figure 2. This course shows that the photocatalyst particles are relatively uniform over the wood cross section in the wood. Immediately at the surface, the particle content, also called pigment content, is about 100%. It then sinks to about 90% at a penetration depth of between 1 and about 7 mm and drops slightly again to about 80% at a penetration depth above 7 mm. It follows that photocatalysts with particle sizes between 20 and 150 nm penetrate very extensively into the wood. The illustration in FIG. 3 relates to photocatalysts with particle sizes between 120 and 300 nm.
• the course 5 of the pigment distribution likewise shown in the upper part of this figure, is established. It can be seen that the pigment content drops from 100 to about 50% to a penetration depth of about 0.5 mm and reduces to a pigment content of about 25% between a penetration depth of 0.5 mm and about 4 mm. Above a penetration depth of about 4 mm, the pigment content remains constant at about 25%.
• FIG. 4 shows the course 5 of the pigment distribution for particle sizes of the photocatalyst between 300 and 800 nm. Up to a penetration depth of about 0.5 mm, the pigment content drops steeply from 100 to about 20%. At a penetration depth above 0.5 mm, the course 5 asymptotically approaches a pigment content of about 0%, which is achieved at a penetration depth between 4 and 5 mm. Thus, FIG. 4 initially shows a relatively steep drop in the pigment content of the at least one photovoltaic catalyst up to a penetration depth of 0.5 mm.
• the penetration properties of the photocatalyst can thus be specifically controlled, so that the photocatalytic effects, for example after processing of the wood surface (grinding, planing, etc.), are retained by using smaller, deeply penetrating photocatalyst pigments.
• the photocatalyst can be fixed in particulate form and / or in particulate form on an inert carrier material and / or embedded in an inert carrier material.
• the carrier material may be, for example, an inert binder or a layered silicate.
• the subsequent application of the photocatalyst can be carried out in the same manner as described above for the wood preservative, ie, for example, by surface methods such as brushing, dipping, spraying, by storage methods such as tray impregnation, or by impregnation methods such as, for example, a pressure impregnation ,
• the at least one biocide may be in dissolved, emulsified, microemulsified, particulate dispersed, microencapsulated or microparticle bound form.
• the distribution patterns shown in FIGS. 2 to 4 apply to pine sapwood, which has been treated by the boiler pressure method.
• the particle size of the at least one photocatalyst can therefore be chosen so that a penetration of the photocatalyst particles is not possible by so-called spotting openings of the wood, ie the individual particles of the at least one photocatalyst are deposited on the surface 3 of the wood.
• the wood is still water vapor permeable after application of the wood preservative and the photocatalyst; it therefore remains open to diffusion.
• the at least one photocatalyst is applied to the surface of the wood, as soon as the photocatalytic action described above has occurred, there are hardly any residues of the at least one organic substance, an organic compound and / or the at least one biocide on the surface.
• the application / introduction of the photocatalyst can be carried out in one stage together with the wood preservative or in two stages after the application or introduction of the wood preservative.
• wood preservative means such means that prevent deterioration or destruction of wood and wood-based materials and thus ensure a long service life of the wood.
• the wavelength of the light irradiated for decontamination is tuned to the absorption characteristics of the biocides used and the photocatalysts used, and that daylight and / or artificial light corresponds to the absorption characteristics of the photocatalysts used.
• organic substances and / or organic compounds and / or biocides are used which are photoinstable, ie unstable when exposed to light.

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• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Wood Science & Technology (AREA)
• Forests & Forestry (AREA)
• Inorganic Chemistry (AREA)
• Chemical & Material Sciences (AREA)
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