EP4144496A1 - Method for processing a wooden item and a wooden item processed by the method - Google Patents

Abstract

The invention relates to a method for processing a wooden body, in particular by wood embossing, comprising the steps of softening the wooden body and pressing the softened wooden body in at least one spatial direction with a pressing force with deformation, in particular embossing, of the same, the deformation being at least essentially permanent , wherein a) the wood body is provided at least on the surface with a first oil A and is made to act on it over a period of time, the oil A as component A being (i) free organic carboxylic acids and/or (ii) fatty acid derivatives and/or resin acid derivatives and/or contains fatty alcohol derivatives, b) the wooden body is exposed to the worked-in oil A in an autoclave in an atmosphere containing steam at elevated temperature, and c) after or during step b), the wood is pressed with mechanical pressure, with deformation of the wooden body. Furthermore, the invention relates to a wooden body produced according to the method.

Description

The invention relates to a method for processing a wooden body, in particular by wood embossing, according to the preamble of claim 1 and a wooden body produced according to the method.

In order to deform wood, it is known to subject the respective piece of wood to a heat treatment before it is deformed, in order to then bring the piece of wood into the desired shape by pressing. Such a method can be carried out without mechanical removal of material, such as milling, and is therefore particularly easy to carry out. The deformation of the piece of wood can take place in a bending process or an embossing process.

The main challenge, however, is that after the deformation in the said process, the piece of wood has as few cracks, fraying or roughening of the surface as possible, which would otherwise require subsequent treatment, for example by grinding. This is particularly the case when high quality surfaces of the processed wooden body are desired. Furthermore, it is a particular challenge not only to deform, in particular to emboss, softwoods such as fir, but also hardwoods such as oak.

When embossing wood, the macroscopic structure of the piece of wood can be brought into a desired shape without removing material, for example to form an ergonomic tool handle from a cuboid wooden body. Large reductions in the volume of the piece of wood are often desired here. On the other hand, there is also a need to carry out very delicate and detailed embossing, in which case the embossing depth can be relatively small, but it should have very high visual fidelity to detail and resolution, for example in the range of a few 1/10 millimeters or less. When embossing, stamps must therefore often be used, which are brought into contact with the surface of the piece of wood over the entire surface and without a gap, which often has to be done continuously over a larger surface area or the entire surface of the piece of wood and/or the entire stamping area. High demands are therefore placed on a method which can carry out both types of deformation with high quality, particularly in the case of different types of wood.

Furthermore, it is desirable that the deformed, in particular pressed and/or embossed, piece of wood is fit for use after the deformation with as little post-treatment as possible, or preferably without post-treatment. This usability usually includes a pleasant haptic feeling of the piece of wood and a very smooth surface. To this end, wooden bodies are often subjected to a final treatment such as grinding or polishing and, if appropriate, subsequent impregnation. But this is very expensive. Furthermore, post-drying of the piece of wood after its deformation is often required, which is labour-, time- and energy-intensive.

For the deformation of the piece of wood, more complex pressing and/or embossing tools are often required, the tool surfaces of which bear against the entire surface of the piece of wood during the deformation process in order to bring it into the desired shape. The piece of wood can then be completely enclosed by the pressing/embossing surfaces of the tool in order to be able to shape it into a complex shape. The method should therefore be suitable for being able to deform the piece of wood in the pressing and/or embossing tool outside of the autoclave in which it is heat-treated.

Furthermore, there is a need to have to carry out the thermal treatment of the wood before it is deformed over only a comparatively short period of time in order to provide an economical process.

Although it is generally known to bring wood into a desired shape after a thermal pre-treatment without removing material, no method has hitherto been known which largely or completely fulfills the above-mentioned requirements.

The object of the invention is to at least partially or completely solve the aforementioned problems. In particular, the invention is based on the object of providing a wood treatment process which enables a high degree of deformation of the piece of wood with a reduction in volume of the same and/or a particularly high level of detail, including fine-grained and preferably large-area embossing, which can also be carried out without cracks, especially in the case of types of wood that are difficult to deform, such as hardwoods which preferably requires only little or practically no post-treatment for the serviceable use of the piece of wood and which is also particularly preferred is economically feasible.

This object is achieved by a method according to claim 1 and by a piece of wood produced by means of this method according to claim 16.

In the course of the invention, it has been found that the at least superficial treatment of the wooden body with an oil A containing component A leads to the wooden body during the subsequent treatment in the autoclave in an atmosphere containing water vapor at elevated temperature with a particularly large reduction in volume of the wooden body during the subsequent Pressing process according to step c) and / or particularly detailed embossing is deformable. Step c) can also be carried out relatively quickly, even in the case of large volume reductions. This deformation during the pressing process c) is at least essentially or almost completely permanent due to the predetermined pre-treatment of the wooden body, ie it remains even if the pressing pressure is removed in step c). In addition, due to the pretreatment with oil A in step a), the wooden body has a particularly high surface quality after the pressing process in step c). The surface quality is characterized in that the wooden body has practically no cracks and/or fraying and a particularly smooth surface, which generally makes post-treatment, in particular also mechanical post-treatment, superfluous. In particular, cracks are avoided which are visible to the naked eye and/or would promote the penetration of moisture into the wooden body.

The process according to the invention can be used to produce softwoods, but in particular also hardwoods, with the production of very delicate surface structures. For example a delicate structure of a stamping surface, which corresponds, for example, to the surface structure of a conventional coin, can be permanently embossed in the piece of wood in step c) in a particularly detailed manner. This allows a variety of surface structures of the piece of wood for functional and / or decorative purposes.

By using component A, the wooden body can also surprisingly be deformed with significantly reduced or no crack formation, and deformation can also take place over a large depth range, ie with a high indentation depth based on a given cross section of the piece of wood. In the case of a piece of wood with a thickness of several centimetres, for example up to 3 cm or up to 5 cm or possibly more, the piece of wood can deform by more than ≥ 20% or ≥ 30%, often also ≥ 40% or up to 50% or optionally ≥ 50% of its thickness, without being limited to this, can be compressed without cracking, so that a corresponding height profile can be pressed into the piece of wood. This is given in particular in combination with a rapid implementation of the method.

The described deformation of the wooden body in step c) can take place in the deformation step by pressing and/or embossing over its entire surface, with the corresponding shaping tool also shaping the wooden body at the end of step c) over its entire surface, preferably continuously and without perforations and / or without a gap, which means that the method can be used in a particularly versatile manner, even when the wooden body is given a complex shape over its entire surface in one deformation step. This also allows complex three-dimensional shapes of the wooden body over its entire surface, for example for the production of hand tool handles from a cuboid preform in one step possible. This also applies to types of wood that are difficult to permanently deform, such as oak, walnut, maple, ash, elm or hardwood in general, relatively tough wood and/or wood that tends to crack.

In addition, when the method is carried out according to the invention, the wooden body does not lose the color characteristic of the respective wood, ie it does not lead to the wooden body fading, as is often the case when other treatment agents are used in step a).

Furthermore, by carrying out the method according to the invention, a post-treatment of the wooden body after carrying out step c) is often no longer necessary, even with different types of wood, and no grinding or polishing to produce particularly smooth wooden surfaces.

"Pressing" in the context of the invention is always understood to mean a compression of the piece of wood with a reduction in volume of the same.

The "deformation" of the piece of wood through application of the method should always be understood as essentially or almost completely permanent deformation.

In the narrower sense, "wood" in the sense of the present invention is understood to mean the hard tissue of the sprout seeds of trees and shrubs, ie the xylem of the seed plants produced by the cambium. In a broader sense, however, this also includes woody tissues of other plants such as palm trees, bamboo or the like, which usually have lignin built into the cell walls.

The terms "piece of wood" and "body of wood" become synonymous here used.

The inventive effect of oil A is attributed to the fact that the components (i), namely free organic carboxylic acids, and / or (ii), namely fatty acid derivatives and / or resin acid derivatives and / or fatty alcohol derivatives, in steps a) and b) the lignin softening of the wood particularly effectively and profoundly, but after step c) has been carried out or the wood body has cooled down again leads to hardening of the lignin or the wood material overall, and also in the deformation and/or embossing of the piece of wood to only a very small or no crack formation in the wood and causes a very detailed fidelity when embossing delicate surface structures.

Component A may be present in the oil A at a level of 5-50% by weight or higher, for example 10-40% or 15-30% by weight, based on the weight of the oil. In general, the proportion of component A in the oil A can be ≧5% by weight, preferably ≧10% by weight, more preferably ≧20% by weight or ≧30% by weight, and generally preferably ≦70% by weight. or ≤ 60% by weight, without being limited thereto. However, component A can also be contained in the oil A in a content of ≧70% by weight or ≧70% by weight, or the oil A can optionally consist entirely of component A.

Free organic carboxylic acids with a carbon number of ≧6 or ≧8, preferably ≧10 or ≧12, are preferably used as component (i). These are more hydrophobic than short-chain carboxylic acids, more oil-soluble and have proven particularly effective. In particular, the free carboxylic acids can be C8-C36 or C10-C30 or preferably C12-C25, C14-C22 acids or generally have ≧6 carbon atoms and/or ≦35 carbon atoms.

The acids of component (i) are preferably fatty acids, for example saturated fatty acids, preferably unsaturated fatty acids, for example monounsaturated, polyunsaturated or conjugated fatty acids. The fatty acids mentioned can be present in combinations with one another. Conjugated fatty acids have two or more conjugated C-C double bonds, those with at least two consecutive trans double bonds are particularly preferred. Component (i) particularly preferably contains monounsaturated, polyunsaturated and/or conjugated fatty acids or combinations thereof. Component (i) particularly preferably contains polyunsaturated, even more preferably conjugated, fatty acids, which have proven to be particularly advantageous compared to monounsaturated or, in particular, saturated fatty acids.

Examples of saturated fatty acids that can be used are myristic acid, palmitic acid and/or stearic acid or combinations thereof. Examples of unsaturated fatty acids that can be used are monounsaturated fatty acids such as oleic acid. Examples of polyunsaturated fatty acids that can be used are linoleic acid, linolenic acid, ricinoleic acid or combinations thereof. As conjugated fatty acids, i.e. those with conjugated C-C multiple bonds, in particular double bonds, 9,11 linoleic acid, elaeostearic acid, licanic acid, paric acid, calendulaic acid, catalpinic acid and/or punicic acid or combinations thereof can be used, preferably also with trans double bonds, in particular consecutive.

Free resin acids can also be used as component (i), for example diterpene acids such as, for example, abietic acids, pimaranic acids, including their isomers, or the like and/or sesquiterpenic acids and/or triterpenic acids. Diterpene acids are preferred. The resin acids are preferably natural resin acids, such as those found in particular in natural tree resins, in particular in gum resins or conifer resins, such as, for example, in Canada balsam or the like. It is also possible to use modifications of these resin acids which, for example, have additional alkyl groups and/or are hydrogenated or dehydrogenated, structural isomers or the like. The resin acids are preferably present in the oil A in dissolved or finely dispersed form, for example depending on the presence of the respective resin acid in natural resins such as gum resins. The rosin acids may generally be incorporated into the Oil A formulation by the use of natural resins such as gum rosins. Resin acids are particularly preferred. However, the oil A can also be free of fatty acids and/or resin acids.

Optionally, free carboxylic acids with <6 carbon atoms can also be present in component A (i), even if these are less preferred because they are less oil-soluble and less active in wood softening and can lead to fading of the piece of wood. Free carboxylic acids with <6 carbon atoms are present in the oil preferably in a content of ≦20% by weight or ≦10% by weight, preferably ≦5% by weight or more preferably ≦2% by weight or not at all .

The free carboxylic acids RCOOH, in particular fatty acids and/or resin acids, can also have other substituents such as hydroxyl and/or carbonyl groups in the R radical, but this is not mandatory. Preferably <30% by weight or <20% by weight or <5% by weight of the free carboxylic acids, based on the total weight of free carboxylic acids, have hydroxyl and/or carbonyl groups in the R radical, or practically none.

The free carboxylic acids RCOOH are generally preferably monocarboxylic acids. If appropriate, polybasic carboxylic acids such as dicarboxylic acids can also be present as component (i) as the free carboxylic acids; more preferably ≦5% by weight based on the total weight of monocarboxylic acids in component (i) or in oil A as a whole, or the oil A is free from polybasic free carboxylic acids.

The content of component (i), ie free organic carboxylic acids, in the oil A can be 5-50% by weight or possibly higher, preferably 10-40% by weight, more preferably 15-30% by weight , optionally also ≥ 2% by weight. The content of component (i) in the oil A can generally also be ≦30% by weight or ≦20% by weight or also ≦15% by weight or ≦10% by weight, in particular if the content of component ( ii) in oil A is sufficiently high. The content of component (i) in the oil A can optionally also be ≧60% by weight or ≧70% by weight. Optionally, the oil A also contains practically no free carboxylic acids.

The content of free fatty acids with a carbon number of ≧6 or ≧8, preferably ≧10 or ≧12, in the oil A can be 5-50% by weight or possibly higher, preferably 10-40% by weight. , more preferably 15-30% by weight.

The content of free saturated fatty acids in the oil A can be 5-50% by weight or possibly higher, preferably 10-40% by weight, more preferably 15-30% by weight. The content of saturated fatty acids in the oil A can also be <30% by weight or <20% by weight or <10% by weight, in particular if a higher proportion of unsaturated fatty acids.

The content of free unsaturated fatty acids in the oil may be 5-50% by weight or higher, preferably 10-40% by weight, more preferably 15-30% by weight. This refers to the total content of mono- and polyunsaturated fatty acids, including conjugated fatty acids.

The content of free monounsaturated fatty acids in the oil may be 5-50% by weight or higher, preferably 10-40% by weight, more preferably 15-30% by weight.

The content of free polyunsaturated fatty acids, in particular free conjugated fatty acids, is particularly preferably 5-50% by weight or higher, preferably 10-40% by weight, more preferably 15-30% by weight in the oil A .

The content of free resin acids in the oil A can be in the range of 5-50% by weight, preferably 10-30% by weight, more preferably 15-30% by weight, optionally also ≦25% by weight or ≤ 10% by weight or ≤ 5% by weight.

Preferably, the fatty acids are non-cyclic aliphatic carboxylic acids.

The oil component A preferably has fatty acid derivatives and/or resin acid derivatives and/or fatty alcohol derivatives as component (ii). The fatty acid derivatives and/or resin acid derivatives are preferably derivatives of the fatty acids or resin acids described as component (i); reference is made in full to the comments on this. Fatty alcohol derivatives of oil component A are preferably alcohols which can be obtained from the free fatty acids mentioned by replacing at least one or preferably all of the COOH groups with a CH2-OH group result, in which case - less preferred - the alcohol can also be a secondary alcohol with the same number of carbon atoms, or possibly also a tertiary alcohol. If free fatty acids and fatty acid derivatives and/or fatty alcohol derivatives are present side by side in oil A, or if free resin acids and resin acid derivatives are present side by side in oil A, the free acids on the one hand and the derivatives mentioned on the other are selected independently from the components described. The fatty alcohols are preferably predominantly, ie ≧50% or ≧75% or preferably ≧85%, based on molar ratios, or fully primary alcohols.

The fatty acids and/or resin acids and/or fatty alcohols of the respective derivatives preferably independently have a carbon number of ≧6 or ≧8, preferably ≧10 or ≧12, which are comparatively hydrophobic and more oil-soluble and have proven particularly useful.

In particular, the fatty acids and/or resin acids and/or fatty alcohols of the derivatives can independently be C8-C36 or C10-C30 or preferably C12-C25, C14-C22 acids or alcohols or generally ≥ 6 carbon atoms and/or ≤ 35 C -Have atoms. The acids or alcohols of the derivatives can be saturated, unsaturated, for example monounsaturated, polyunsaturated or conjugated fatty acids or combinations thereof. Conjugated fatty acids have two or more conjugated CC double bonds, particularly preferably those with conjugated trans-trans double bonds. Component (ii) particularly preferably contains monounsaturated, polyunsaturated and/or conjugated fatty acids or combinations thereof. Component (ii) more preferably contains polyunsaturated and/or conjugated fatty acids. The fatty acids of component (ii) can be, in particular, those as described for the free fatty acids of component (i), regardless of the presence of free fatty acids in oil A. The resin acids of component (ii) can be, in particular, such as these the free rosin acids of component (i), regardless of the presence of free rosin acids in oil A.

The fatty acid residues and/or resin acid residues and/or fatty alcohol residues of the respective derivatives are preferably present independently of one another at least partially or predominantly or almost completely as terminal groups or side groups of the respective molecule, in particular as side groups. Preferably ≥ 50% or preferably ≥ 75% or ≥ 85% or ≥ 95% or practically all of the fatty acid residues are present as terminal groups and/or side groups of the respective molecule, based on the molar number of these groups. Correspondingly, this can also apply, independently of one another, to the resin acid residues and/or fatty alcohol residues. As a result, these residues with their functional binding groups such as in particular ester groups in steps a) and/or b) can act particularly well on the wood components of the piece of wood, in particular also lignin, to soften the piece of wood. This therefore differs from compounds in which such components are part of the basic structure or backbones of polymers. The fatty acid residues and/or resin acid residues and/or fatty alcohol residues mentioned are thus preferably only once derivatized, ie connected to another molecule residue only at one acid or alcohol group.

The fatty acid residues and resin acid residues are generally the RCOO- residues of the respective fatty acids or resin acids RCOOH understood. Fatty alcohol residues are generally understood to be the RO residues of the respective fatty alcohols ROH.

The derivatives of the fatty acids and/or resin acids and/or fatty alcohols mentioned are each independently of one another preferably esters of the same, so that the derivatization is therefore in the ester formation. These have proven to be particularly effective with regard to the possible reduction in volume of the piece of wood when it is pressed and/or the attention to detail of the embossing process when embossing a delicate ornament. The derivatives are preferably present to an extent of more than 50% by weight or more than 75% by weight or preferably more than 90% by weight as esters. If necessary, the derivatization can also take place in another way, for example by forming amides or the like. However, esters have proven particularly useful for achieving the advantages according to the invention.

The derivatives can optionally be modified by other groups, for example by reaction with epoxy resins and/or polyethers or other customary functionalizing groups, in order to modify the properties of oil A, such as its curing properties.

Various modifications are made to fatty acid derivatives, in particular fatty acid esters, with the formation of isocyanates and/or siloxanes, as are known, for example, in the case of wood preservatives. In the case of oil A, there is preferably no modification of components, particularly preferably not component A, with siloxanes and/or isocyanates, or preferably at least only to an extent which does not affect the performance properties of oil A.

However, the said modification or the derivatization in general should preferably not be so strong that the oil A is already essentially or completely hardened when the piece of wood is introduced into the autoclave. Alternatively or independently of this, the said modification or derivatization should generally not be so strong that the oil A noticeably, essentially or completely loses its property of being absorbed into the wood, i.e. not only forming a film on the surface of the piece of wood.

In general, oil A preferably dries open-pored on the wood rather than forming a film after it has been applied to the wood. The oil A is preferably a drying oil, which therefore preferably forms and resinifies oxidation products under the action of atmospheric oxygen.

Generally preferably, Oil A is a one-component system. To carry out the method according to the invention, it is therefore preferable not to use a second component such as a hardener, in particular not a hardener in liquid, paste-like or solid form which is chemically reactive with the oil A or its components and before the oil A is applied mixed with it and stored separately from oil A. The oil A is preferably storable and can be applied to the piece of wood without being mixed with a second component.

The esters of the fatty acids and/or resin acids of the derivatives mentioned are preferably esters of monohydric to hexahydric alcohols or mixtures thereof, preferably of monohydric and/or dihydric and/or trihydric alcohols or mixtures of such esters, but possibly also of tetrahydric , five or hexavalent alcohols.

In particular, the esters of the fatty acids and/or resin acids can be esters of monohydric alcohols and/or esters of dihydric alcohols, in particular glycol, in particular glycol diesters, for example of ethylene glycol and/or propylene glycol. In particular, the esters of fatty acids and/or resin acids can be esters of trihydric alcohols, in particular glycerol esters, in particular mono-, di- or more preferably trihydric glycerol esters, ie mono-, di- or triglycerides, particularly preferably triglycerides. The esters mentioned of monohydric, dihydric and/or trihydric alcohols can also be present in a mixture with one another. The esters mentioned then each preferably have only 1 to 5 alcohol residues or ≦3 alcohol residues or only one alcohol residue as molecular building block. Esters of this type have proven particularly useful for achieving the advantages according to the invention. The respective alcohol of the ester can be, for example, ethylene glycol, propylene glycol or a 1,2-diol with ≦10 or ≦6 or ≦4 carbon atoms or a monohydric fatty alcohol and/or diterpene alcohol and/or sesquiterpene alcohols and/or triterpene alcohol, in particular fatty alcohol , particularly preferably fatty alcohol with ≥ 6, preferably ≥ 8 or ≥ 10, particularly preferably ≥ 12 carbon atoms, but optionally also from methanol, propanol or butanol. The fatty alcohol can have ≦40 carbon atoms or ≦30, particularly preferably ≦25 or ≦20 carbon atoms. The respective alcohols of the esters can, in particular, be plants of natural origin, in particular of plant origin, or corresponding nature-identical alcohols.

As component (ii) it is possible in particular to use esters, in particular glycerol esters such as mono-, di- or triglycerides or mixtures thereof, of monounsaturated fatty acids such as oleic acid, polyunsaturated fatty acids such as linoleic acid, linolenic acid, ricinoleic acid or combinations thereof. In particular, 9,11 linoleic acid, elaeostearic acid, licanic acid, paric acid, calendulaic acid, catalpinic acid and/or punicic acid or combinations thereof can be present as conjugated fatty acids with conjugated CC double bonds, preferably each with trans double bonds, in particular consecutive trans double bonds. In general, esters of linoleic acid and/or linolenic acid have proven particularly useful.

In particular, esters of resin acids such as, for example, diterpenic acids such as abietic acids, pimaranic acids, including their isomers, or the like and/or sesquiterpenic acids and/or triterpenic acids can also be present as component (ii).

The fatty acids, resin acids and/or fatty alcohols, also as constituents of components (i) and/or (ii), are preferably natural acids and/or alcohols, more preferably of vegetable nature or corresponding essentially nature-identical substances. Fatty acid derivatives and/or resin acid derivatives and/or fatty alcohols of vegetable origin, such as vegetable oils, are particularly preferred as component (ii). Vegetable oils often contain esters of relatively long-chain fatty acids with a high content of unsaturated, in particular polyunsaturated and/or conjugated fatty acids, which have proven to be particularly advantageous. Corresponding vegetable oils which have high levels of such fatty acid esters are, for example, linseed oil, soybean oil, rapeseed oil, safflower oil, castor oil, nut oils such as walnut oil, palm oil, sunflower oil or the like. These oils can form at least some or all of component (ii) or component A of oil A and can be an essential part of oil A. The as a component Fatty acids, resin acids and/or fatty alcohols used in (i) and (ii) can each also be obtained by modifying and/or derivatizing natural fatty acids, resin acids and/or fatty alcohols, e.g. in the form of a compound with polyethers, epoxides, possibly less preferably or also excluded from siloxanes and/or isocyanates. The modification and/or derivatization can also be carried out, for example, by rearrangement, transesterification, isomerization, hydrogenation of double bonds and/or dehydrogenation and/or hydration and/or dehydration. The fatty acids, resin acids and/or fatty alcohols used as component (i) and (ii) may also not be modified and/or derivatized by polyether and/or epoxide and/or siloxane and/or isocyanate groups. In particular, the fatty acids, fatty acid esters, resin acids, resin acid esters and/or fatty alcohols based on natural compounds thereof can also generally not be modified and/or derivatized, which can apply independently to the compounds mentioned.

According to the invention, the fatty acids and/or resin acids and/or fatty alcohols of component (ii) can optionally also be bonded in particular as terminal groups or side groups to an oligomeric or polymeric backbone, in particular an organic backbone. The backbone can be, for example, a suitably functionalized polyether and/or polyester, for example an alkyd resin. The oligomeric or polymeric backbone, such as alkyd resin, preferably has only a low degree of oligomerization or polymerization, so that the resin does not form a film after application to a wooden body, but rather penetrates into the wooden body. Thus, generally lower degrees of oligomerization or polymerization are preferred, so that the substance is thinner and easier to penetrate into the wood can penetrate. The oligomer and/or polymer is preferably adjusted in such a way that it is not yet fully cured when the piece of wood is introduced into the autoclave to carry out step b). The oligomer or polymer preferably has ≦250 or ≦100 or ≦50, preferably ≦25 or ≦10 radicals from the group of fatty acid radicals, resin acid radicals and fatty alcohol radicals, as the number of radicals per molecule, particularly preferably ≦5, for example 3 as with triglycerides .

The oil A can contain ≦25% by weight or ≦10% by weight, optionally ≦5% by weight or ≦2% by weight, of alkyd resins or be free of alkyd resins.

Preferably, at ≥ 25% by weight, preferably ≥ 50% by weight or ≥ 75% by weight or ≥ 85% by weight, more preferably ≥ 95% by weight or 100% by weight of the fatty acid derivatives, in particular fatty acid esters of component (ii) of oil A, these ≦250 or ≦100, preferably ≦50 or ≦25, more preferably ≦10 or in particular ≦5 fatty acid residues per molecule, for example 1-3 fatty acid residues, and are more preferably in the form of diglycerides or triglycerides or mixtures of di- and triglycerides, in particular in the form of triglycerides. This preferably applies independently instead of the fatty acid derivatives, in particular fatty acid esters, to the resin acid derivatives, in particular resin acid esters, and/or to the fatty alcohol derivatives, in particular fatty alcohol esters, in each case of component (ii) of oil A. The fatty acid, resin acid or fatty alcohol derivatives mentioned above are relatively low molecular weight, so that the advantages of the invention arise in a special way.

Component (ii), i.e. fatty acid derivatives and/or resin acid derivatives and/or fatty alcohol derivatives in combination, may be present in the oil A at a level of 5-50% by weight or higher, for example 10-40% or 15-30% by weight, based on the weight of the oil. In general, the proportion of component (ii) in the oil A can be ≥ 5% by weight, preferably ≥ 10% by weight or ≥ 20% by weight or ≥ 30% by weight, more preferably also ≥ 40% by weight. -% or ≥ 50% by weight or ≥ 75% by weight, or the oil may consist entirely of component (ii). The content of component (ii) can also be ≦70% by weight or ≦60% by weight, without being restricted thereto.

The content of fatty acid derivatives in the oil A is preferably 5-50% by weight or higher, for example 10-40% or 15-30% by weight, based on the weight of the oil. In general, the proportion of fatty acid derivatives in the oil A can be ≧5% by weight, preferably ≧10% by weight or ≧20% by weight or ≧30% by weight or ≧50% by weight, but also ≧ 60% by weight or ≧70% by weight, optionally also practically 100% by weight. The content of fatty acid derivatives in the oil A can generally also be ≦70% by weight or ≦60% by weight, without being limited thereto. In particular, these levels may apply to the level of fatty acid esters in the oil. These contents can particularly preferably apply to fatty acid derivatives, in particular fatty acid esters, with ≦250 or ≦100 or ≦50, preferably ≦25 or ≦10 or ≦5 fatty acid residues. These contents can particularly preferably apply to fatty acid esters in the form of triglycerides.

The content of the fatty acid residues in the fatty acid derivatives, preferably in the form of esters, in the oil A, which represent unsaturated fatty acid residues, is preferably ≥ 5% by weight or ≥ 10% by weight, preferably ≥ 20% by weight or ≥ 30% by weight %, more preferably ≧40% by weight or ≧50% by weight, but also ≧60% by weight or ≧70% by weight, based on the total weight of the fatty acid residues of the fatty acid derivatives. The content of unsaturated fatty acid derivatives or esters in relation to the fatty acid residues of the derivatives mentioned, in particular esters, can generally also be ≦70% by weight or ≦60% by weight, for example also ≦50% by weight, without being limited thereto to be. In particular, the stated contents of fatty acid residues in the fatty acid derivatives, preferably in the form of esters, in the oil A can each apply to polyunsaturated fatty acid residues. In particular, the contents of fatty acid residues mentioned in the fatty acid derivatives, preferably in the form of esters, in the oil A can each apply to conjugated fatty acid residues.

If the fatty acid derivatives mentioned, in particular in the form of esters, are mixed derivatives or esters, in which saturated fatty acids are also present in one molecule with regard to unsaturated fatty acids, or in which other fatty acids such as unsaturated fatty acids are also present with regard to polyunsaturated fatty acids /or monosaturated fatty acids are present, or in which, with respect to conjugated fatty acids, other fatty acids such as non-conjugated fatty acids are also present,

The content of rosin acid derivatives in the oil A is preferably 5-50% by weight or higher, for example 10-40% by weight or 15-30% by weight, based on the weight of the oil. In general, the proportion of resin acid derivatives in the oil A can be ≧5% by weight, preferably ≧10% by weight or ≧20% by weight or ≧30% by weight or ≧50% by weight, but also ≧ 60% by weight or ≧70% by weight, optionally also practically 100% by weight. The content of the resin acid derivatives in the oil can also be ≦70% by weight or ≦60% by weight, without being limited to this. In particular, these levels can apply to the level of rosin acid esters in the oil.

The content of fatty alcohol derivatives in the oil A is preferably 5-50% by weight or higher, for example 10-40% by weight or 15-30% by weight, based on the weight of the oil. In general, the proportion of the fatty alcohol derivatives in the oil A can be ≧5% by weight, preferably ≧10% by weight or ≧20% by weight or ≧30% by weight, in particular also ≧50% by weight or ≧ 60% by weight or also ≧70% by weight, optionally also practically 100% by weight. The content of fatty alcohol derivatives in the oil can generally also be ≦70% by weight or ≦60% by weight, without being restricted to this. In particular, these levels can apply to the level of esterified fatty alcohols in the oil.

These abovementioned contents can particularly preferably apply to resin acid derivatives, in particular resin acid esters, and/or fatty alcohol derivatives, in particular esterified fatty alcohols, with ≦250 or ≦100 or ≦50, preferably ≦25 or ≦10 or ≦5 resin acid residues or fatty alcohol residues.

The content of component (ii) in the oil A may be higher than the content of component (i) in the oil A, each based on weight percent with respect to 100% by weight of oil A. The weight proportion of component (ii) in the oil A can be higher, for example, by a factor of ≧1.2 or ≧1.5, preferably by a factor of ≧2 or ≧3 or ≧5, than the content of component (i) in the oil A, in each case based on their proportions by weight in the oil A. Optionally, the content of the fatty acid derivatives, in particular fatty acid esters, and/or the content of the resin acid derivatives, in particular resin acid esters, and/or the content of the fatty alcohol derivatives, in particular in the form of esters, can be greater than that of component (i) in the oil A, for example by a factor of ≥ 1.2 or ≥ 1.5, preferably by a factor of ≥ 2 or ≥ 3 or ≥ 5 higher than the content of component (i) in the oil A, based in each case on their proportions by weight in the oil A. This avoids excessively high acid contents in the oil A and allows gentle treatment of the piece of wood in the method according to the invention. Optionally, however, the content of component (i) in the oil A can be higher than the content of component (ii) or the content of the fatty acid derivatives, in particular fatty acid esters, and/or the content of the resin acid derivatives, in particular resin acid esters, and/or the content of fatty alcohol derivatives, especially in the form of esters.

Preferably ≧5% by weight, preferably ≧10% by weight, ≧25% by weight, for example 10-40% by weight, more preferably 15-30% by weight, preferably ≧50% by weight or ≥ 75% by weight or ≥ 85% by weight, more preferably ≥ 95% by weight of the fatty acid esters of component (ii) of oil A esters of monohydric to hexahydric alcohols, preferably dihydric and/or trihydric alcohols, or each mixtures of the same. The fatty acid esters are particularly preferably ≥ 5% by weight, preferably ≥ 10% by weight, ≥ 25% by weight, for example 10-40% by weight, more preferably 15-30% by weight, preferably ≥ 50 % by weight or ≧75% by weight or ≧85% by weight, more preferably ≧95% by weight of diglycerides or triglycerides or mixtures of di- and triglycerides. The alcohols are preferably not linked to other alcohols in the molecule.

The substances used as component (i) and/or as component (ii) are generally preferably at least partially or completely liquid at the treatment temperature of the piece of wood in the autoclave, resulting in increased reactivity of the same with the wood components, in particular lignin, in step b). .

The substances used as component (i) and/or as component (ii) generally preferably have a melting point of ≦100° C., preferably ≦80° C. or ≦60° C., more preferably a melting point of ≦40° C. or ≦ 30°C, most preferably a melting point of ≦20°C, which can apply to at least part of the respective component, for example >50% by weight or >75% by weight or >90% by weight thereof, or each independently for component (i) and/or component (ii) as a whole. Components (i) and/or (ii) are therefore preferably at least partially or completely liquid when applied to the wood body and/or when it acts on it in step a), preferably > 50% by weight or > 75% by weight. -% or >90% by weight of the same, which can apply independently to component (i) and/or component (ii) as a whole. This results in the advantages according to the invention in a special way. As a result, these components (i) and/or (ii) can penetrate more easily into the wood pores and soften the wood more quickly and effectively, for example by reacting with the lignin of the wood.

Components (i) and/or (ii) are particularly preferably oil-soluble, for example in a C10-C12 alkane and/or an essential oil, which accounts for ≧25% by weight or ≧50% by weight or ≧75% by weight. % of components (i) and/or (ii) or for the full components (i) and (ii).

The components (i) and/or (ii) are particularly preferably dissolved in the oil A and/or in a form such as those present in a natural gum resin, for example finely dispersed, which in each case accounts for ≥ 25% by weight or ≥ 50% by weight or ≥ 75% by weight of the same or can apply completely to the respective substances.

The oil A may contain other additives, for example in the range of 5-30% by weight, for example about 15% by weight, which are different from the aforementioned components (i) and (ii). The additives can be, for example, biocides, wood preservatives, agents against blue rot, color pigments, solid resin components (with the exception of resin acids), optionally diluents, preferably without diluents. The additives can be present in the oil A, for example, in dissolved or dispersed form.

The deformation of the wooden body in step c) usually takes place with a permanent reduction in volume of the wooden body. The wood can be compressed as a result and, due to the higher density that is then present, has an improved surface compared to the non-compressed wood body. The compaction or reduction in volume due to the deformation of the wooden body in step c) can be, for example, ≧10%, ≧20%, but usually also ≧30% or up to 40-50%, based on the volume of the piece of wood the implementation of the method according to the invention. This is not only the case with types of wood with a kilned density of < 500 kg/m ³ such as fir, but also with hardwoods with a kilned density of > 500 kg/m ³ such as walnut (kiln dried density: 650 kg/m ³ ) , oak (kiln density approx. 710 kg/m ³ ) or the like. It goes without saying that with types of wood with an extremely high kilning density, such as certain tropical woods, ironwood or the like, lower compaction or volume reductions can be achieved.

Furthermore, it has been found that hardwoods also have particularly high-quality surfaces which are free of cracks and/or fraying and which are particularly are smooth.

In the context of the invention, “kiln density” is generally understood to be the density of the wood after drying at 103° C. to constant weight, preferably in dry air, in particular in air with 0% humidity at 103° C. and 1013 hPa.

During the compaction of the wood, it can be compressed to up to 50% of its original volume in step c), which is possible due to the treatment with the oil A used. This enables a particularly high compression of the wood. On the one hand, the shape of the piece of wood originally used, for example a cuboid piece of wood, can be changed in many ways. Furthermore, due to this high compression of the wood, after the method according to the invention has been carried out, it is also particularly insensitive and mechanically stabilized to external environmental influences such as water, mechanical stresses such as the introduction of scratches, etc.

It has been found to be particularly preferred if component A consists at least partially of components that harden in air. In particular, free carboxylic acids and/or carboxylic acid esters can be used for this purpose, in which case the carboxylic acids of the respective components are unsaturated fatty acids and/or esters of unsaturated acids. With regard to the free acids and/or the esters, the respective unsaturated acids are preferably unsaturated fatty acids. Through the use of air-hardening components, the piece of wood produced according to the invention has a particularly smooth surface and/or a surface with a particularly pleasant haptic feeling. Further as a result, post-treatment of the piece of wood deformed in step c) is required only to a small extent or not at all.

The oil can contain further components such as varnishes, essential oils, balsamic resins, hydrocarbons and/or higher alcohols, in particular with ≧6 or ≧10 or ≧12 carbon atoms. The components mentioned can be contained in the oil in a content of ≦80% or ≦60%, or else ≦40% or ≦30%. The hydrocarbons can be, for example, paraffins and/or mono- and/or di- and/or sesqui- and/or triterpenes. All components of oil A preferably have a melting point which is less than or equal to the maximum treatment temperature of the piece of wood in the autoclave, preferably ≦140°, particularly preferably ≦100°.

The oil A can contain other components such as biocides, wood preservatives, wood care products, fillers, color pigments or the like, also solvents and/or diluents such as essential oils, terpenes or the like, optionally also other oil components that form the oil body of the oil. The oil A can contain these or other further components in a content of ≦75% by weight, or ≦50% by weight, preferably ≦35% by weight, or ≦20% by weight, optionally also ≦10% by weight. -% included, but not limited to. Oil A can also contain solvents and/or thinners to improve its creeping properties and penetration into the wood, such as essential oils, orange oil or turpentines such as gum turpentine (resin effluent from conifers) or balsams. Preferably, pure hydrocarbons in the oil A are not or only in a small amount such as <50% by weight or <20% by weight or <10% by weight or 5% by weight or practical not included, which can also apply independently of this to the content of free alkanes, such as those contained in paraffin oils.

The oil A preferably has a dynamic viscosity of ≦2500 mPas or ≦1000 mPas, particularly preferably ≦500 mPas or ≦250 mPas, more preferably ≦100 mPas, for example approx. 50 mPas. As a result, the oil A is relatively, preferably very thin, so that it penetrates the wood pores very easily and the piece of wood can therefore be deformed after the autoclave treatment with a relatively large reduction in volume and/or great attention to detail when embossing surface structures. Within the scope of the invention, the viscosity is generally determined according to EN ISO 3219, October 1994 version, at 23° C. with a shear rate of 100 s ⁻¹ , determined using a Brookfield viscometer, coaxial cylinder configuration with a standard arrangement.

The wooden body is treated with the oil A before step b) is carried out for a period of ≧2 hours or ≧4 hours, particularly preferably ≧8 hours or ≧12 hours. Exposure to oil A over a period of about 24-48 hours is particularly preferred. The exposure preferably takes place over a period of ≦5 days or ≦4 or ≦3 days, it also being possible for exposure times to be longer than 5 days to be carried out. The application of the oil A preferably does not take place over a too long period of time in order to avoid volatilization of components and/or in the presence of air-drying or air-hardening components of the oil, for example unsaturated fatty acids, and/or excessive hardening of the oil before the to avoid autoclaving. Preferably, the oil A is not fully cured before the wooden body is placed in the autoclave. The oil A is preferably not completely dried before the wooden body is introduced into the autoclave. The terms "hardening" and "through drying" refer to the terminology customary for treating wood with oils, in particular primers and hardwax oils.

The piece of wood is treated with the oil A in step a) preferably at room temperature (20° C.), optionally also at a slightly elevated temperature such as ≦50° C. or ≦30-40° C., generally preferably above 10° C., without to be limited to this.

The oil A can be applied to the wooden body by a conventional application of the oil A to the wooden body, for example by spreading the oil, immersing the wooden body in the oil A or the like. It is sufficient here if the oil A can drip off the wooden body after it has been applied. Optionally, however, the wooden body can also be permanently immersed in the oil A over the period of exposure, although this is usually not necessary.

As a rule, a single application of the oil A to the wooden body is sufficient before this is introduced into the autoclave to carry out step b), usually also in the case of wood which is difficult to deform, such as hardwood with a very high kilning density. However, under certain circumstances, it may also be subjected to repeated application of oil A.

Optionally, the oil A can also be applied to the piece of wood after a vacuum treatment of the piece of wood, in particular while the vacuum is being applied to the piece of wood. This allows the oil to penetrate the pores of the wood more easily. This has in particular with hardwoods with comparatively high kilning density as preferred in order to be able to treat the piece of wood in step c) with a comparatively high volume reduction and/or high level of detail of structural impressions.

After step a) and before step b), the wooden body is particularly preferably treated at least on the surface with a second oil B, the oil B being different from the oil A. The oil B has at least one wood pore-closing component B, which is present in the oil A in a smaller proportion, for example only up to 75%, preferably only up to 50% or only up to 25% or only up to 10% of the content of the Oil B, is included, or preferably the oil A contains a wood pore-closing component B practically not. It has been found that this means that the wooden body can be compressed with a larger volume with otherwise the same treatment with oil A and/or delicate surface structures can be embossed into the wooden body in more detail than without the use of oil B, without impairing the wooden body such as cracking respectively. Without being bound by theory, it is assumed that the oil B causes volatilization and/or hardening or setting of components of the oil A during the pretreatment of the piece of wood in step a) and/or during the treatment of the piece of wood in the autoclave is diminished. This allows the oil A to have a better effect on the piece of wood, especially during the autoclave treatment. This also significantly reduces the penetration of moisture or water vapor into the piece of wood during the autoclave treatment, so that post-drying of the piece of wood after step c) is required to a much lesser extent or practically no longer. It can thus surprisingly pieces of wood with comparatively low residual moisture by means of the invention Process are deformed without these tearing, for example tearing perceptible by visual inspection and / or smaller cracks, which would facilitate the penetration of moisture into the finished wooden body. Surprisingly, this also applies to hardwoods or woods that are difficult to deform, such as ash, maple, oak or the like. The treatment with oil B has also proven particularly effective for hardwoods, for example those with a kiln density of ≧550 kg/m ³ or ≧650 kg/m ³ , such as oak wood. By using oil B, post-treatment of the wooden body by impregnation is not necessary for most applications, in particular to provide a water-repellent and/or haptically attractive wooden surface. As a result, it is usually not necessary to re-oil the wooden body.

Furthermore, the surface of the wooden body when using the oil B after carrying out step c) has a particularly pleasant feel and is particularly smooth. In addition, the wood surface does not feel greasy, even if the oil A used is one which does not at least essentially harden when steps a) and b) are carried out.

The wood pore-closing component B of the oil B preferably has a melting point of ≦180° C. or ≦140° C., preferably ≦120° C. or ≦100° C. Component B can be softened at the maximum temperature of the autoclave treatment, in particular manually kneadable or be at least partially or completely liquid. It has been found to be preferable, particularly with regard to the pore-closing properties, if component B, which closes the wood pores, has a melting point of ≧40° or ≧50°, for example also ≧60° or ≧70°. This application of oil B is particularly preferred in the case of hardwoods with a high kiln density, such as oak or tropical woods. As a result, the formation of cracks, including the formation of micro-cracks, fraying of the wood and other surface defects during the pressing process are significantly reduced or almost completely avoided.

The wood pore-closing component B can in particular be a wax or contain a wax. In particular, the waxes of oil B can have a melting point as indicated above. Natural hard waxes have proven to be particularly preferred, such as caranuba wax, candellila wax, or other corresponding natural waxes, optionally also beeswax, with caranuba wax, for example, being more preferred due to its higher melting point. If necessary, microwaxes, paraffin waxes or the like can also be used.

It has been shown that the advantages of the treatment with oil B are already apparent when the oil B contains the corresponding wood pore-closing component B, in particular in the form of waxes, in a content of ≥ 1-2% by weight or ≥ 3% by weight % or ≧4% by weight, the content of component B, in particular wax, in the oil can be ≦20% or ≦15%, for example also ≦10%, without being restricted thereto.

The oil B can contain other components such as vegetable oils, fatty acids, essential oils, balsamic resins, ISO paraffins or the like, also in combination with one another.

Otherwise, the composition of oil B can at least essentially correspond to that of oil A.

With regard to the application of the oil B to the wooden body, reference is made to the statements on the application of the oil A, it being possible for the application of oil A and oil B to differ from one another.

It has been found to be particularly preferred if the wooden body is treated with the oil B after the oil A has acted on the wooden body for a period of ≧5 minutes or ≧10 minutes, particularly preferably approx. 30-90 minutes or possibly longer has. As a result, the oil A can already penetrate to a certain depth into the wood body, which results in the advantages according to the invention in a special way. The treatment of the wooden body with the oil B preferably takes place within a period of ≦5-6 hours or ≦4 hours, for example ≦2.5 hours, after the wooden body has been exposed to the oil A. It is generally preferred that the time interval Z1 between the application of the oil B and the application of the oil A to the wooden body is substantially smaller than the time interval Z2 between the application of the oil B and the introduction of the wooden body into the autoclave; the time interval Z1 is preferably ≦50% or ≦25%, particularly preferably ≦10% of the time interval Z2. As a result, after the oil A has been applied to the wood body, the wood pores of the same are at least partially closed by the components of the oil B, so that any volatile components of the oil A volatilize to a significantly lesser extent and/or components of the oil A that dry in the air, such as unsaturated fatty acids and/or unsaturated fatty acid esters do not set or solidify as quickly. The treatment of the wooden body in the autoclave can thus be carried out more effectively, for example with a greater reduction in volume and/or more detailed fidelity of introduced surface embossing. The treatment of the wooden body in the autoclave can also be used for a lower period.

The oil B is preferably applied to the wooden body for a period of ≧2 hours or ≧4 hours, preferably ≧8 hours or ≧12 hours, for example approx. 20 hours, before the wooden body is subjected to process step b). As a result, the oils A and B can be drawn into the wood body in a particularly favorable manner, which has proven to be particularly effective in achieving the advantages according to the invention.

The oil A and/or the oil B is preferably not layer-forming when applied to the wooden body, i.e. it does not form a surface layer that hardens or has hardened on the surface of the wooden body, such as a varnish, but rather penetrates the wood, preferably completely. Preferably component (i) and/or component (ii) of Oil A is non-coating when applied to the wood body.

Oil A and/or oil B is preferably not water-based, i.e. it preferably has a water content of ≦40% by weight, preferably ≦20% by weight or ≦10% by weight, particularly preferably ≦5% by weight. % or ≤ 2% by weight is more preferably practically anhydrous. This promotes the oil A or B being drawn into the wood body and in particular the reaction of the oil components, in particular the oil components (i) and/or (ii) with the wood components such as lignin, in order to cause the wood body to soften in step b). can. Optionally, but less preferably, the oil A and/or the oil B can also be used as an aqueous emulsion.

Preferably, in process step b), the wooden body treated in an autoclave at a temperature of 60°C to 180°C in an atmosphere containing steam. Preferably the treatment temperature is in the range of 70-160°C, more preferably in the range of 80-140°C, for example 90-120°C. On the one hand, as a result, the oil A or the oils A and B can soften the wooden body in a particularly effective manner in order to bring about a reduction in volume and/or the imprinting of surface structures during the pressing process. On the other hand, too high treatment temperatures of the piece of wood are avoided. It has been found that the mentioned temperature selection also avoids cracks such as visible cracks, micro-cracks, fraying of the piece of wood and the like, and a particularly well-behaved wood surface can thus be achieved during the pressing process.

Step b) is preferably carried out in the autoclave at a pressure of ≦5 bar, preferably ≦3 bar. The autoclave pressure is particularly preferably ≦2 bar, in particular also ≦1.8 bar or ≦1.6 bar. The autoclave pressure is preferably greater than 1 bar, ie excess pressure compared to atmospheric pressure, preferably ≧1.05 bar or ≧1.1 bar or ≧1.2 bar, typically 1.1-1.5 bar. Under certain circumstances, the autoclave pressure can also be approx. 1 bar. Within the scope of the invention, the stated pressure is generally understood to be absolute pressure. It has been found that the advantages according to the invention in relation to the wood body produced result in a special way with these prints. It has been found that only a relatively low overpressure is sufficient and expedient for at least essentially or practically crack-free deformation of the wooden body, even with hardwoods, the softening of the wood in step b) being promoted by the application of pressure. On the other hand, it has been found that too high autoclave pressure, in particular in the case of an autoclave atmosphere containing steam, leads to increased cracking in the wood and/or usually requires complicated wood drying after step c) has been carried out in order to provide usable wood. For many applications, such as furniture or parts of kitchen appliances, it is desirable for the ready-to-use wood to have a residual moisture content of ≦12% or ≦15%.

When carrying out step b), the autoclave preferably has an atmosphere containing water vapor, with a water saturation of >15%, preferably >35% or >50%, particularly preferably ≧75% or ≧85%, more preferably the atmosphere is practical fully saturated with water vapor. In the context of the invention, the stated water vapor saturation generally relates to the saturation under the respective autoclave conditions. The specified percentage of water vapor saturation corresponds to the relative humidity under the respective autoclave conditions. It has been found that the water vapor atmosphere results in the advantages of the method according to the invention through the action of oil A or oils A and B in a particular way, to a greater extent as the water vapor saturation of the atmosphere increases. This refers both to the deformability of the piece of wood during the pressing process with a reduction in volume and to the embossing of surface structures in combination with a surface of the piece of wood that is free of cracks and fraying, which is then particularly smooth. The water vapor atmosphere in the autoclave can be controlled accordingly and is preferably set or regulated to a predefined water vapor saturation, in particular maximum water vapor saturation. This has proven particularly advantageous in the case of hardwoods in particular.

In the method, a wooden body is preferably provided for carrying out step a), which has a residual moisture content of ≦25% or ≦20%, particularly preferably ≦15%, more preferably ≦12%, for example in the range of 6-12%. The residual moisture content of the wood can be ≥ 2% or ≥ 4%, it being advantageous to present a wooden body with a residual moisture content that is not too low in order to avoid cracking during the deformation process or in a subsequent step such as cooling the wooden body. It has been found that the use of the method according to the invention is particularly advantageous in order to provide high-quality wood surfaces or pieces of wood which are free of cracks, fraying or the like and thus have particularly smooth surfaces as the product of the process. On the other hand, the method according to the invention is particularly suitable for deforming wooden bodies with the residual moisture mentioned, so that drying of the wood is no longer necessary after step c) has been carried out. The wooden body after carrying out step c) can thus already have the residual moisture required for usable wood, for example in the range of 6-12%. As a result, the process can also be carried out particularly economically. The residual moisture content of the wood can generally be determined within the scope of the invention according to DIN-EN 13183-1, 2002 version. The above-mentioned residual moisture content of the wooden body also preferably corresponds to the residual moisture content of the wooden body when it is placed in the autoclave.

Surprisingly, it has been found that the dwell time of the piece of wood in the autoclave can be dimensioned particularly short in the method according to the invention, which results in a particularly economical procedure. The length of stay can typically be considered the conditions such as temperature, pressure and water vapor saturation and the type of wood in the range from 10 minutes to 1 hour, for example approx. 30 minutes, often only 5 minutes or even less if the desired deformation or indentation depths are very small, without being limited to this be. It goes without saying that, particularly in the case of hardwoods, the aim should not be too short a period of time. Per 1 millimeter of press-in depth, with large-area press-in in the range of 1 cm ² or more, for example ≧10 cm ² or ≧100 cm ² , the residence time in the autoclave can typically be 0.5 to 5 minutes, often less than 3 minutes or less than 2 minutes, typically in the range of 1 minute. The offset thus corresponds to the uniform cross-sectional reduction of the wooden body during the pressing process over the specified cross-sectional area. The press-in depth with a reduction in volume can generally be ≧1-2 centimeters or ≧3 centimeters, possibly also up to 5 centimeters or possibly even more, without being limited to this. It goes without saying that depth profiles with a corresponding profile depth can also be pressed into the piece of wood in one process step.

The deformation of the wood body carried out by volume reduction can thus generally amount to a large-area, continuous offset in the range of centimeters offset, also with depth profiles. During the pressing process, the pressing jaws of the pressing tool can also lie against the surface of the piece of wood over the entire surface and without a gap. Large-volume wooden bodies can thus be processed, such as furniture parts such as armrests or backrests of chairs or the like, handles such as tools or knives or the like.

The implementation of the deformation of the piece of wood can at suitable devices within the autoclave, or the piece of wood can be removed from the autoclave and fed to a separate device for deforming the same, for example for compression with a reduction in volume and/or embossing of surface structures. It should be ensured that the piece of wood does not cool down too much; the piece of wood should preferably have a temperature of ≧65° C., preferably ≧70° C., if necessary ≧75° C., when the deformation process is being carried out. For carrying out the deformation process, it is sufficient or even advantageous if the temperature of the piece of wood is not higher than the autoclave temperature. This prevents the piece of wood from solidifying under excessive cooling, which would make deformation more difficult.

The pressure to be applied during the deformation process depends on the type of wood selected for the piece of wood and the deformation to be carried out, typically this can be a pressure of 10-300 kg/cm ² or 20-200 kg/cm ² , but is not limited to this . The pressing process can be carried out in the range of minutes or less than 1 minute with press-in depths in the centimeter range.

Some of the oils A that can be used according to the invention are available, for example, as porous wood primers, and oils B are variously available as hard wax oils for treating wood.

Exemplary embodiments of the invention are described below, which indicate typical compositions and process conditions, but are not to be understood as limiting.

Typical compositions of Oil A and Oil B according to the invention are as follows, without being limited to these:

Oil A

• example 1
  Oil A has or consists of the following components:
  • 30-60% by weight of fatty acid esters, for example approx. 40% by weight of fatty acid esters, specifically in the form of triglycerides, with 80-90% by weight of unsaturated fatty acid residues in relation to the total weight of fatty acid residues of the fatty acid esters or triglycerides, in particular about 65% by weight of triunsaturated fatty acid residues in relation to the total weight of fatty acid residues of the fatty acid esters or triglycerides, for example fatty acid esters in the form of linseed oil,
  • 15-30% by weight of free fatty acids and/or free resin acids, in combination with one another, preferably only resin acids,
    • for example about 20% by weight of resin acids,
    • the resin acids can be introduced into the oil formulation by using natural resins such as gum resins,
  • 10-40% by weight of liquid oil base, for example approx. 25% by weight, e.g. essential oils and/or isoparaffins, excluding the aforementioned components,
  • 5-30% by weight of other additives, for example approx. 15% by weight, different from the components mentioned above, for example biocides, wood preservatives, agents against blue rot, color pigments, solid resin components, with the exception of resin acids, optionally diluents, preferably without diluents ( in each case excluding the aforementioned components, the additives can be present in the oil A in dissolved or dispersed form.
  An oil A is commercially available, for example, as a primer hard oil for wood treatment.
  Oil A can contain less than 700g/litre of volatile organic components (VOC), for example approx. 500-660g/litre, in particular according to the EU limit value cat. A7f.
  Oil A has a dynamic viscosity of approx. 50 mPas at 23°C.
• Example 2:
  like oil A according to example 1 with the difference:
  • 30-60% by weight fatty acid esters, specifically in the form of triglycerides, but with about 80% by weight saturated fatty acid residues in relation to the total weight of fatty acid residues of the fatty acid esters or triglycerides and about 20% by weight simple or polyunsaturated fatty acid residues in relation to the total weight of fatty acid residues of the fatty acid esters or the triglycerides.
• Example 3:
  like oil A according to example 1 with the difference:
  • 30-60% by weight of fatty acid esters, specifically in the form of triglycerides, but with about 60% by weight of conjugated unsaturated fatty acid residues in relation to the total weight of fatty acid residues of the fatty acid esters or triglycerides and about 40% by weight of unsaturated fatty acids , non-conjugated fatty acid residues by total weight on fatty acid residues of the fatty acid esters or the triglycerides.
• Example 4:
  Olive oil. The olive oil usually consists at least essentially, preferably at least ≧95% by weight or preferably ≧98%, of triglyceride esters of fatty acids, with about 7-20% by weight, in particular about 14% by weight, of the fatty acid residues. % are saturated fatty acid residues, especially palmitic acid residues, about 55-83 wt.%, especially about 77 wt.% are monosaturated fatty acid residues, especially oleic acid residues, and about 9 wt.% are polysaturated fatty acid residues, especially linoleic acid residues , are, which for the fatty acid residues refers to the total content of the fatty acid residues present as triglycerides.

oil b Example 1:

• 20-40 Gew.-% Fettsäureester, im Speziellen in Form von Triglyceriden, mit 90 Gew.-% ungesättigte Fettsäurereste in Bezug auf das Gesamtgewicht an Fettsäureresten der Fettsäureester bzw. der Triglyceride, insbesondere ca. 30 Gew.-% dreifach ungesättigter Fettsäurereste in Bezug auf das Gesamtgewicht an Fettsäureresten der Fettsäureester bzw. der Triglyceride,
• 20-40 Gew.-% an freien Fettsäuren und/oder freien Harzsäuren, in Kombination miteinander, bevorzugt auch nur Harzsäuren,
  die Harzsäuren können durch Verwendung von natürlichen Harzen wie bspw. Balsamharze in die Ölformulierung eingebracht werden,
• 4-15 Gew.-% Wachse, insbesondere Hartwachse
• 10-35 Gew.-% flüssiger Ölgrundkörper, z.B. ätherische Öle und/oder Isoparaffin, ausgenommen zuvor genannte Komponenten,
• 10-30 Gew.-% weitere Zusatzstoffe, verschieden von den zuvor genannten Komponenten, beispielsweise Biozide, Holzschutzmittel, Mittel gegen Blaufäule, Farbpigmente, feste Harzbestandteile, ausgenommen Harzsäuren, gegebenenfalls Verdünnungsmittel, vorzugsweise ohne Verdünnungsmittel (jeweils ausgenommen zuvor genannte Komponenten,
  die Zusatzstoffe können in gelöster oder dispergierter Form in dem Öl A vorliegen.

Oil B has or consists of the following components:

• 20-40% by weight of fatty acid esters, especially in the form of triglycerides, with 90% by weight of unsaturated fatty acid residues in relation to the total weight of fatty acid residues of the fatty acid esters or triglycerides, in particular approx. 30% by weight of triunsaturated fatty acid residues in Referring to the total weight of fatty acid residues of the fatty acid esters or triglycerides,
• 20-40% by weight of free fatty acids and/or free resin acids, in combination with one another, preferably only resin acids,
  the resin acids can be introduced into the oil formulation by using natural resins such as gum resins,
• 4-15% by weight of waxes, especially hard waxes
• 10-35% by weight of liquid oil base, e.g. essential oils and/or isoparaffin, excluding the aforementioned components,
• 10-30 wt.
  the additives can be present in the oil A in dissolved or dispersed form.

An oil B is commercially available, for example, as a hardwax oil for treating wood.

Oil B can contain a maximum of 700g/litre of volatile organic components (VOC), for example approx. 400-500g/litre, in particular according to the EU limit value cat. A7f.

Oil B has a dynamic viscosity of approx. 50 mPas at 23°C.

process conditions Treatment with oil A (step a):

• superficial generous application of oil A to the wooden body by brush application or immersion, with oil A draining off until there are no drips
• Application of oil A approx. 24-48 hours before autoclave treatment, oil A is not yet fully hardened when the wooden body is placed in the autoclave, preferably not yet fully dried.

The wooden body is cuboid as a test body, here as an example with edge lengths of 5 cm x 5 cm x 20 cm.

The wooden body consists of hardwoods which are difficult to deform, such as oak, walnut, ash, maple, elm, beech or the like, in particular oak.

Before treatment with oil A, the wooden body has a residual moisture content of approx. 10%.

Treatment with oil B (step a):

• superficial generous application of oil B to the wooden body by brush application or dipping with oil B draining off until there are no drips
• Application of oil B approx. 30-90 minutes after application of oil A, oil A is not yet fully hardened when the wooden body is placed in the autoclave, preferably not yet fully dried.

Autoclaving (Step b)

• Carry out approx. 24-48 hours after applying oil A
• Autoclave temperature: 80-90°C
  Duration of the autoclave treatment: 15 minutes for the test piece of wood, which is compressed at least in areas, preferably over a large area, in step c) in its thickness by approx. 1 cm with a volume reduction, correspondingly longer with a larger volume cross-section reduction,
• Autoclave pressure: approx. 1.25 bar
• Autoclave atmosphere: air with water vapor saturation of 50-100%, preferably approx. 100%, under autoclave conditions

Deformation procedure (step c)

a) Pressing with strong reduction in volume Deformation of the wooden body with a maximum cross-section reduction of approx. 2.5 cm by the pressing tool, pressing of the test specimen to dimensions of up to 2.5 cm x 5 cm x 20 cm, with plane-parallel surfaces.

Pressing with plane-parallel surfaces takes place in several stages. Several wooden bodies treated in this way are produced during the pressing according to step c), the insets of which were increased in steps of 5%, starting from an inset of 30% of the maximum inset, i.e. starting from an inset of 0.75 cm, up to one maximum offset of 2.5 cm corresponds to 100% of the offset.

According to one variant, the pressing-in takes place during the pressing process with the introduction of a height profile, with the areas of maximum height having a height difference of 1.25 cm from the areas of minimum height. The profile runs essentially linearly between the areas of maximum height and minimum height, ie in the transition areas of the same. The areas of maximum height and minimum height are arranged alternately to one another. All of the areas of maximum height, the areas of minimum height and the transition areas between these each have the same longitudinal extent over the length of the wood body. The areas of minimum and the areas of maximum inset depth each extend over t 25% of the wood body surface. b) embossing process

Embossing process: Embossing a stamp with a delicate pattern with a resolution of the surface structure in the range of 0.1-0.5 mm, for example in the form of a coin, over a continuous square area of 50 cm x 50 cm The embossing process can take place alternatively or in combination with the pressing of the test specimen with a strong reduction in volume according to variant a).

In the deformation process a) and the embossing process b), the stamp causing the deformation lies flat, preferably over the entire surface, on the surface of the piece of wood during the deformation of the wooden body, with the profile depth of the stamp generally being less or significantly less than over the entire stamp surface within the scope of the invention the pressing depth of the stamp into the piece of wood can be, for example, about 25% or about 50% or about 75% of the same.

Example 1

The wood body is treated with oil A according to Example 1 under the process conditions indicated for the treatment, without treatment with oil B, and then subjected to the indicated conditions of autoclaving and the deformation process, in particular high-shrinkage pressing or embossing processes.

The wooden body can be pressed with plane-parallel surfaces or alternatively with a height profile, each with approx. 70% of the maximum inset depth of 2.5 cm, without visible crack formation and with regard to a manually palpable roughness with a good surface and without significant fraying. When pressing with a height profile, the profile depressions have an offset of approx. 70% of the maximum offset. The wooden body accepts the embossing structure well in the embossing process. The wood body surface feels slightly oily, which is useful for some applications, for other applications, where one for a manual handling or tactile special advantageous surface is desired, but requires after-treatment, in particular to improve the surface feel or to reduce the oiliness of the surface. Compared to the initial state, the wooden body has an increased residual moisture content and must be dried again to make it usable.

Example 2

As example 1, but with additional treatment of oil B under the same treatment conditions of oil A and with the same autoclave treatment and implementation of the deformation process as in example 1.

The wooden body can be pressed with plane-parallel surfaces or alternatively with a height profile, each with up to approx. 75-80% of the maximum inset depth of 2.5 cm, without visible cracking. When pressing with a height profile, the profile depressions have an offset of approx. 75-80% of the maximum offset. The surface of the wood piece has a smoother touch than that in Embodiment 1. The surface of the wood has a very good haptic, comfortable feeling and feels dry and not oily. The wooden body has a lower residual moisture than in embodiment 1, here of about 12%, and does not need to be dried.

Example 3

As embodiment 2 with treatment of oil B, but using oil A from example 2 instead of oil A from example 1, under otherwise identical process conditions.

The wooden body can be pressed with plane-parallel surfaces or alternatively with a height profile, with a significantly lower offset without visible cracking, here of approx. 55% of the maximum offset of 2.5 cm. When pressing with a height profile, the profile depressions have an offset of approx. 55% of the maximum offset. During the embossing process, the embossing structures show good fidelity to detail, but slightly worse than in embodiment 2. The surface of the piece of wood has a slightly rougher surface than in embodiment 2, but smoother than in embodiment 1. The wood surface has a very good haptic, pleasant feel and feels dry. The wooden body has a lower residual moisture than in embodiment 1, here of about 12%, and does not need to be dried.

Example 4

As embodiment 2 with treatment of oil B, but using oil A according to example 3 under otherwise the same process conditions.

The wooden body can be pressed with plane-parallel surfaces or alternatively with a height profile up to the maximum inset depth of 100%, i.e. to approx. 2.5 cm, without visible cracking. When pressing with a height profile, the profile depressions have an indentation depth of approx. 2.5 cm. During the embossing process, the embossing structures have a very high level of detail, better than in exemplary embodiment 2. The surface of the piece of wood has a very smooth, practically optimal surface. The wooden surface has a very good haptic, pleasant feeling and feels dry. The wooden body has a residual moisture content of approx. 12% and does not need to be dried afterwards.

In the embodiments 2 to 4 is a post-treatment of the piece of wood such as subsequent impregnation and / or Drying of the piece of wood is not required. The wooden bodies have very good water-repellent properties with increased long-term stability.

Example 5

As example 1 using the oil according to example 4, i.e. olive oil, without using oil B, under otherwise the same treatment conditions, autoclave treatment and implementation of the deformation process as in example 1. The attention to detail in the embossing process is similar to example 1.

The wooden body can be pressed with plane-parallel surfaces or alternatively with a height profile, each with up to approx. 60-65% of the maximum inset depth of 2.5 cm, without visible cracking. When pressing with a height profile, the profile depressions have an offset of approx. 60-65% of the maximum offset. The crack-free press-in depth is therefore somewhat less than in exemplary embodiment 1.

The surface of the piece of wood feels significantly rougher than in exemplary embodiment 1 and shows little fraying. The wooden surface has a very good haptic feeling, but worse than in embodiment 1. The surface still feels oily and sticky and requires a post-treatment such as impregnation for high-quality applications such as manually handled tool parts such as knife handles. The wooden body has a similar residual moisture content as in example 1.

Comparative example 1:

As embodiment 1, but instead of oil A, pure paraffin oil (white oil) is used under otherwise identical process conditions.

The wooden body has a significantly lower softening in relation to the depth profile of the wooden body than in embodiment 1, essentially only over less than half the depth extension into the wooden body. The softening of the wood body takes place only over about 40% to 45% of the depth as in embodiment 4, ie about 40-45% of the maximum pressing depth. The press-in depth without visually recognizable crack formation is therefore only about 40-45% of the maximum press-in depth according to exemplary embodiment 4. The pressing-in of the profile according to the described variant of the press-in test takes place with crack formation. Embossing a stamp with a delicate pattern results in only a blurred embossing contour. The surface of the wooden body after step c) feels distinctly oily to greasy and unacceptable for manual handling. The surface shows clear fraying and requires mechanical post-processing such as grinding. After step c), the wooden body has a high residual moisture content of approx. 18% and requires drying. Furthermore, white oils are harmful to health and, as mineral oil products, are not renewable raw materials.

In terms of roughness, haptics and water-repellent properties, the wooden body also has a poorer appearance than in exemplary embodiment 1 and has a greater tendency to fray. The wooden body feels very greasy. The wooden body has a high level of residual moisture and must be dried afterwards.

Comparative example 2:

As Example 1, but instead of oil A, a lower alcohol such as methanol/ethanol is used under otherwise the same process conditions.

A softening of the wooden body is found, but over a much smaller depth than when using oil A according to embodiment 1. The wooden body softens only over about 40% of the depth as in embodiment 4, i.e. about 40% of the maximum pressing depth . The press-in depth without crack formation recognizable by visual inspection is therefore only about 40% of the maximum press-in depth according to exemplary embodiment 4. The wooden body shows clear to severe fraying. In the case of compression as in exemplary embodiment 1, there are severe cracks in the wood body and this is not fit for use. The pressing of the profile according to the described variant of the pressing test takes place with crack formation, the embossing of a stamp with a delicate pattern only results in a blurred embossing contour, in each case with somewhat poorer results than according to comparative example 1. The wooden body is very strongly faded and unsightly, at least superficially after the autoclave treatment and therefore from the surface impression for all applications in which the wooden body should have a wood look can not be used. The wooden body has a high level of residual moisture and must be dried afterwards.

Claims (16)

Method for processing a wooden body, in particular by wood embossing, comprising the steps of softening the wooden body and pressing the softened wooden body in at least one spatial direction with a pressing force with deformation, in particular embossing, of the same, the deformation being at least essentially permanent, characterized in that a) that the wooden body is provided at least on the surface with a first oil A and is made to act on it over a period of time, with the oil A as component A (i) free organic carboxylic acids,
and or (ii) fatty acid derivatives and/or resin acid derivatives and/or fatty alcohol derivatives
contains b) that the wooden body is exposed to the worked-in oil A in an autoclave in an atmosphere containing water vapor at elevated temperature, and c) that after or during step b) the wood is pressed with mechanical pressure with deformation of the wooden body. Method according to claim 1, characterized in that (i) the free organic carboxylic acids are fatty acids and/or resin acids,
and or (ii) that the fatty acid derivatives are fatty acid esters and/or the rosin acid derivatives are rosin acid esters and/or the fatty alcohol derivatives are fatty alcohol esters. Method according to claim 1 or 2, characterized in that
that in relation to component A (ii), the fatty acid residues and/or resin acid residues and/or fatty alcohol residues of the respective derivatives are independently present at least predominantly as terminal groups or side groups. Process according to one of Claims 1 to 3, characterized in that the esters of component A (a) C8 to C30 fatty acid esters and/or (b) are esters of di- and/or sesqui- and/or triterpene carboxylic acids. Process according to one of Claims 1 to 4, characterized in that component A, in particular components (i) and/or (ii), consists at least partly of components which harden in air, in particular components with unsaturated CC bonds. The method according to any one of claims 1 to 5, characterized in that the component (i) and / or the component (ii) in the oil A each independently or in combination with each other in a content of ≥ 5 wt .-% or ≥ 10 % by weight is/are included. Process according to one of Claims 1 to 6, characterized in that the oil A has a dynamic viscosity of ≤ 2,500 mPas according to EN ISO 3219 at 23°C, preferably ≤ 1000 mPas. Method according to one of Claims 1 to 7, characterized in that the wooden body is exposed to the oil A for a period of ≥ 2 hours and preferably ≤ 5 days before carrying out step b). Method according to one of Claims 1 to 8, characterized in that after step a) and before step b), the wooden body is treated at least on the surface with a second oil B, which is different from oil A, the oil B closing at least one wood pore Component B contains. Method according to claim 9, characterized in that the wood pore-closing component B is a wax or contains a wax. Method according to one of claims 9 or 10,
characterized in that (i) the wooden body is treated with the oil B after the oil A has acted on the wooden body for a period of ≥ 10 minutes,
and or (ii) the oil B is allowed to act with the wood body for a period of ≥ 2 hours before the wood body is subjected to process step b). Method according to one of claims 1 to 11,
characterized in that in process step b) the wooden body is treated at a temperature of 60° to 180° in the steam-containing atmosphere in the autoclave. Method according to one of claims 1 to 12,
characterized in that the pressure in the autoclave in step b) is ≤ 5 bar, preferably ≤ 2 bar. Method according to one of claims 1 to 13,
characterized in that the water vapor atmosphere in the autoclave when carrying out step b) has a water saturation of ≥ 15%, preferably ≥ 50%, in relation to the autoclave conditions. Method according to any one of claims 1 to 14 above,
characterized in that the wood body treated with oil A and/or oil B has a residual moisture content of ≤ 15%. Wooden body produced by the method according to any one of claims 1 to 15.