CH712354A2 - Process for improving the impregnability of sawn timber. - Google Patents

Abstract

The invention relates to a method for increasing the capacity of lumber for liquid wood-modifying substances, wherein an elongated wooden blank with longitudinally arranged Baumleitgefässen, in particular a tree trunk, branch or an elongated part of a tree trunk or branch, at an angle between 0 and 75 degrees , in particular from 3 to 30 degrees, with respect to its longitudinal axis, is cut obliquely, so that at least a part of the tree guide vessels located in the wooden blank is obliquely cut or cut through the incision. The invention further relates to diagonally cut timbers produced in this way and their use.

Description

Description TECHNICAL AREA

The present invention relates to a process for the production of sawn timber with increased absorption capacity for liquid wood-modifying substances.

STATE OF THE ART

The trend in the wood industry is moving away from film-forming paints to wood treatment processes, especially surface treatments that allow the wood-modifying substances to penetrate into the wood. The wood thus produced looks more natural and the substances can not peel off.

Normally logs are cut as accurately as possible along the trunk longitudinal axis or parallel to the trunk longitudinal axis and processed into saw products such as boards, planks, posts, prisms or veneers. It is also known and customary that wood is cut transversely to the trunk axis, ie at an angle of 90 degrees to the trunk axis, as a so-called "end grain", which can be used, for example, for the production of end grain floors.

However, woods that are cut parallel to the trunk axis, but have only a very limited capacity and loading capacity for liquid wood-modifying substances, in short: impregnating agent. There is therefore a need for a method by which one can increase the capacity and loading capacity of lumber for the loading of impregnating agents of various kinds and which is suitable for use in industrial lumber production and processing. Such a method is defined in claim 1, further advantageous embodiments are described in the dependent claims.

DESCRIPTION OF THE INVENTION

In the course of the present invention, it has been found that in woods which are cut parallel to the trunk axis, the capacity for liquid impregnating agent, which are to penetrate into the wood, is very limited. However, as soon as the tree guide veins - quasi the "veins" of the tree - are cut, the absorption capacity increases even at very small, flat cutting angles, relative to the longitudinal axis of the tree trunk or branch, immediately quite considerably. After tree trunks and branches do not always run straight and also the tree guide vessels are not strictly rectilinear, several such zones with obliquely cut Baumleitgefässen slightly different orientation can be in a longer board, so over the length of the board both different loading characteristics occur, as well varied, optical appearance arises.

By a pre-selected incision angle these desired properties can be induced on the entire board. Overall, this measure causes at least a significantly increased capacity for liquid impregnating materials compared with wood, which is cut conventionally along the trunk longitudinal axis or parallel to this. In addition, this also improves the uniformity of the surface treatment.

The invention therefore relates in a first embodiment to a method for increasing the absorption capacity of lumber for liquid wood-modifying substances, wherein an elongated wooden blank with longitudinally arranged Baumleitgefässen, in particular a tree trunk, branch or an elongated part of a tree trunk or branch, is cut obliquely at an angle between 0 and 75 degrees, in particular from 3 to 30 degrees, with respect to its longitudinal axis, so that at least a part, usually the entirety, of the tree guide vessels located in the wooden blank is cut or cut through the incision obliquely.

Wood pieces made according to this invention are typically cut at an angle between 0 and 75 degrees, preferably in a range of 3 to 30 degrees, to the longitudinal axis. Another positive side effect of this cutting direction is a novel, characteristic cross-sectional image with a specific sequence of open or closed, oval or elliptical annual rings that is reminiscent of a rift or half-strand pattern. It is surprising that even structurally poor woods such as beech, maple or birch not only get a new cut through the oblique incision, but also a detailed, highly detailed wood drawing, which is completely lacking in conventional longitudinal cuts.

The invention also relates to such obliquely cut wood parts and lumber products with increased absorption capacity for liquid wood-modifying substances in which at least a part, usually all, the present in the timber product Baumleitgefässe are obliquely on or cut through the incision. This is the result of the oblique incision of an oblong wooden blank having longitudinally extending tree guide vessels at an angle between 0 and 75 degrees, in particular at an angle of 3 to 30 degrees, with respect to the longitudinal axis of the timber blank. The wood blank may be a tree trunk, a branch or an elongated part of a tree trunk or branch made therefrom by conventional incision.

The wood parts according to the invention can be applied with all conventional wood-modifying substances of natural or synthetic origin. These are, in particular, lacquers, mordants, colorants, natural resins, synthetic resins, bleaching agents, substances for pH modification, waxes, oils, tanning agents and / or other wood-modifying substances.

Methods of treating wood, especially lumber, with wood-modifying substances are known in the art (see, for example, EP 0 891 244 B1, entire document) and include methods such as spraying, coating, dipping and immersion, and others. Likewise known from EP 0 891 244 B1 are numerous substances which can be used for wood modification, such as e.g. in claims 2 to 6 of EP 0 891 244 B1.

These include, for example, biodegradable polymers such as polyhydroxybutyric acids, polycaprolactones, polylactic acids, polyesters based on diols and dicarboxylic acids, polyamides, polyester urethanes, chemically modified natural polymers such as e.g. cellulose acetates; but also fats, oils, waxes, lignin, alcohols. The fats may be hydrogenated or modified animal and vegetable fats, e.g. hydrogenated vegetable fats, epoxidized oils, wool fat, tallow, but also salts of various fatty acids, e.g. Stearic acid, behenic acid, or lauric acid.

Also various salts, such as. As phosphates, borates, sulfates, chlorides, or silicates can be used together with the liquid substances or mixtures of substances for wood impregnation. They can exert a positive influence on the reduction of swelling and shrinkage, but they also have a flame-retardant and / or fungicidal effect.

Glycerol can be used as a "solvent", plasticizers or humectants, while alkali and Erdalkaliresinate act as drying agents, but can also be used as wetting agents and emulsifiers and thereby promote the penetration of molten resins into the wood.

For pH change, for example, sodium hydroxide or citric acid can be used. Examples of "other wood-modifying substances" include substances such as acetic anhydride or furfuryl alcohol.

Insofar as reference is made here to "liquid" wood-modifying substances, it is intended to mean both liquid at room temperature and those which are solid at room temperature, but melted by heating or heating and then used in liquid form for impregnating the woods can be. These include e.g. most resins and waxes.

The impregnation of the inventive wood parts is very different from that for conventionally cut saw products, since the capacity of the inventive wood parts for any type of wood-modifying substances is considerably increased. This is particularly evident in the fact that most of the substances penetrate deep into the wood and, together with the wood substance, form an intimate connection. As a result, it is surprisingly possible to dye wood parts over the entire cross-section or to load them with tannins, which is virtually impossible with conventionally produced lumber pieces.

An effect of this substantially increased substance intake is that these wood parts, even with larger layer thicknesses, i. E. in a range of 5 to 20mm, can be made translucent. On the other hand, it is due to this increased absorption capacity somewhat more difficult to achieve a greater layer thickness of a desired impregnating agent on the wood surface, as is usually desired, for example, in painted wood surfaces. Here, however, one can make do with a multilayer paint system and / or by increasing the viscosity of the corresponding paint.

Contrary to previous experience in the impregnation of reverted woods, such as spruce, it is now possible to load these types of wood with a variety of substances, so to modify and thus to improve their performance characteristics significantly. "Exploitation" refers to the spontaneous closure of the tree guide vessels immediately after precipitation, as is especially noticeable in spruce wood. Another positive side effect of this type of cut is also that the hardness, in contrast to wood parts made from longitudinal sections, is substantially increased or can be increased by hardness-modifying substances.

The preparation of the novel wood parts can be effected in that a wooden blank, usually a tree trunk or branch, in a suitable saw, such as a band saw, is clamped so that a cutting angle in a range between 0 and 75 degrees, especially in one Range of 3 to 30 degrees, to the longitudinal axis of the tree trunk is achieved in one operation.

Alternatively, one can also first on a first saw, e.g. a gang saw, elongated wood blanks in the form of posts, planks or prisms according to conventional longitudinal section produce, which then followed by a second saw, e.g. a circular or bandsaw to be cut obliquely at the desired angle to the trunk longitudinal axis in the range between 0 and 75 degrees, in particular in a range of 3 to 30 degrees.

The thickness of the chisel cut wood produced in this way can vary widely, but it is usually in a range of 1 to 40, in particular from 5 to 30 millimeters. It is also possible, by means of suitable knives, to produce veneers of typically 0.5 to 8 mm thickness with the corresponding novel woodcut pattern and the improved loading properties.

The wooden parts thus produced, including the veneers, can be adhered to other conventional wood parts or wood materials as a carrier. This is especially true for layer thicknesses in the lower region, i. in the range of 0.5 to 10mm, because the bending strength of the beveled lumber is reduced compared to conventional longitudinally cut wood parts. The use of bevelled timbers for constructive purposes is possible, but limited, i. Depending on the layer thickness, the addition of carrier material for mechanical reinforcement may be required. For use in the production of multi-layered parquets, however, the oblique lumber produced according to the invention seems virtually predestined.

The following examples show a comparison of the loading of various diagonally cut wood species with different wood treatment agents. EXAMPLE 1: Loading of Different Woods with Oil [0024] Oil used: Legno oil from the company Adler.

The loading was carried out by immersion of the wood samples in the oil pressure-free at a temperature of about 22-25 ° C (room temperature). The reference value is given as the quantity of oil taken up under identical conditions of a wood cut along the trunk axis by conventional incision type as 100%, the cutting angle being 0 degrees.

A) wood species spruce

Table 1

Incision angle in degrees Oil absorption in% 0 b) wood type ash

Table 2

Incision angle in degrees Oil absorption in% 0 100 15 140 30 180 45 220 60 260 75 320 90 370 c) Beech wood

Table 3 [0030]

Incision angle in degrees Oil absorption in% 0 100 15 220 30 230 45 230 60 240 75 240 90 350 EXAMPLE 2: Loading of different woods with wood varnish [0031] Paint used: Floor Classic from Adler

The loading was carried out by immersing the wood samples in a pan filled with paint, pressure-free, at a temperature of about 22-25 ° C (room temperature). The reference value given is the quantity of varnish taken up under identical conditions of a wood cut along the trunk axis by conventional incision type as 100%, the cutting angle being 0 degrees.

A) wood species fir

Table 4

Incision angle in degrees Lacquer uptake in% 0 100 15 190 30 210 45 210 60 310 75 320 90 300 b) Pine wood species

Table 5 [0035]

Incision angle in degrees Paint absorption in% 0 100 15 200 30 190 45 210 60 200 75 360 90 370 c) Wood species Oak

Table 6

Incision angle in degrees lacquer absorption in% 0 100 15 210 30 230 45 240 60 240 75 240 90 230 EXAMPLE 3 Loading with Resin and Wax The substance mixture consists of 66% by weight tall resin (Sacotan 85, Krems Chemie) and 34% by weight montan wax (Iscoblend 207, Schliekum company), the softening point is 80 degrees Celsius. Before loading the wood parts, both the substance mixture and the wood parts are heated to 110 degrees Celsius. Subsequently, the melt is applied to the wooden parts until no further recording takes place.

As a reference value, the amount of recorded under identical conditions resin-wax mixture of a conventional Schnittschnittart along the trunk axis cut wood is given as 100%, the cutting angle is 0 degrees.

A) wood species fir

Table 7 [0041]

Incision angle in degrees substance in% 0 100 5 280 15 300 30 310 45 300 60 310 75 320 90 300 b) wood species pine

Table 8 [0043]

Incision angle in degrees Substance absorption in% 0 100 5 200 15 200 30 220 45 210 60 230 75 330 90 340 c) Wood species Oak

Table 9 [0045]

Incision angle in degrees substance uptake in% 0 100 5 180 15 210 30 220 45 210 60 230 75 220 90 240 [0046] The tests and experiments carried out in the course of the invention have also given the following findings: - Inclined timbers, which have an incision angle produced by more than 30 degrees, can be difficult to process industrially. It is difficult to manipulate, transport or cut them because some of their mechanical properties, in particular the flex cracking properties, are reduced over those of conventionally cut wood. The industrial planing of such beveled timbers is virtually non-existent or only from layer thicknesses of 10 mm and more, because they break easily and may even destroy the planing machine under certain circumstances.

So if you want to edit thin slanted lumber, which have been made with incision angles of more than 30 degrees, you have to previously on a stable carrier, typically a carrier wood, glue, only then you can plane them.

However, it has also been found that these mechanical properties, e.g. the breaking strength, only at large incision angles, i. at incision angles greater than 30 degrees, especially at incision angles of 45-75 degrees, whereas at incision angles of 3 to 30 degrees they deviate only slightly from those of conventionally cut wood (= 0 degree incision angles).

The advantages of the novel beveled timbers with respect to their modifiability by natural or artificial chemical substances are evident even at very small incision angles. It is surprising that the absorption capacity for such substances is disproportionately increased even in the lowest incision angle range of about 3-20 degrees. There is also no linear relationship between incision angle and loading capacity, as can be clearly seen from the examples. Rather, there are discontinuities or erratic changes, which among other things of the type of wood, the wood hardness, the incision angle, the straightness or rest and restlessness of the inner wood structure including the Baumleitgefässe, the content of resins and moisture, a possible Verkül-ment of Timber, and possibly other factors depend.

Overall, it can also be seen that about half to two-thirds of the maximum possible loading capacity can already be achieved at incision angles between 0 and 30 degrees. This is especially evident in wood species which hardly absorb wood-modifying substances in a conventional longitudinal section, such as e.g. Spruce. With such types of wood the capacity is unexpectedly large even at very small incision angles.

By wood-modifying substances, for example, the surface hardness and / or the total hardness of the sawn timber product can be increased in a very targeted manner, since the hardness-modifying substances are absorbed in liquid form in the wood, where they then cure chemically or physically. Likewise, the swelling and shrinkage properties of the diagonal cut wood can be improved by impregnation with water-repellent substances, since less moisture can be absorbed.

Due to the obliquely cut Baumleitgefässe the inventive diagonal cut timbers such wood-modifying substances can be rapidly absorbed even without pressure application, since they prefer to suck into the wood along the tree guide. If you also create pressure, it is faster. Advantageously, the loading with wood-modifying substances can be accomplished pressure-free or at significantly lower pressures than would be usual or necessary for the loading of conventionally sliced timbers.

The absorption capacity can of course also be supported by the heating of the wood-modifying substances and / or the wood piece to be processed.

Claims (9)

- Incision angle between 0 and 30 degrees, in particular from 3 to 30 degrees are also preferred because only as long as possible beveled timbers of up to 3 meters in length can be produced, as desired by the panel industry in the rule or in part even required. The parquet industry prefers 50-90 cm long beading. Even with the use of logs with large trunk diameters, ie relatively expensive wood, therefore, the choice of cutting angles in industrial lumber production are practically limited by the range of 0 to 30 degrees, in particular from 3 to 30 or 5 to 30 degrees, sufficient be covered. Of course, a carpenter or carpenter can also use other cutting angles, if this corresponds to the customer's request. However, most of the advantages mentioned above already result in a cutting angle range of approximately 3 to 30 degrees, which is why this range is particularly preferred. The bevel cut wood and wood products produced according to the invention can be used for many purposes, for example for the production of parquets, wainscoting, ceilings, stair elements, veneers, decorative elements, boards, boards, and / or of two or more layered wood materials in various forms, e.g. in plate form as so-called cross laminated wood. claims A method for increasing the absorption capacity of sawn timber for liquid wood-modifying substances, characterized in that an elongated wooden blank with longitudinally arranged Baumleitgefässen, in particular a tree trunk, branch or an elongated part of a tree trunk or branch, at an angle between 0 and 75 degrees, in particular from 3 to 30 degrees, with respect to its longitudinal axis, is cut obliquely, so that at least a part of the tree guide vessels located in the timber is inclined through the incision or cut through. 2. The method according to claim 1, characterized in that the wood blank is clamped in a suitable saw so that its longitudinal axis with respect to the cutting direction of the saw an angle between 0 and 75 degrees, in particular from 3 to 30 degrees, includes, and in this position is cut. 3. The method of claim 1 or 2, characterized in that sawed in a first step on a first saw, such as a frame saw, wood blanks in the form of conventional posts, planks or prisms from a tree trunk or branch, from which subsequently to a second saw , For example, a circular or band saw, bevel cut wood with a cutting angle between 0 and 75 degrees, in particular from 3 to 30 degrees, cut. A lumber product having increased absorbency for liquid wood-modifying substances, characterized in that the lumber product comprises tree-guiding vessels, part or all of which are slanted or cut as a result of an oblique incision of an elongated timber blank provided with longitudinally-extending tree guide vessels Angle between 0 and 75 degrees, in particular from 3 to 30 degrees, relative to its longitudinal axis. 5. lumber product according to claim 4, loaded with at least one liquid wood-modifying substance from the group of paints, mordants, colorants, natural resins, resins, bleaching agents, substances for pH change, waxes, oils, alcohols and tannins. 6. lumber product according to claim 4 or 5, with a layer thickness of 0.5 to 40 mm. 7. lumber product according to one of claims 4 to 6, glued to a support material, preferably a support material made of wood. 8. lumber product according to claim 4, prepared by a process according to any one of claims 1 to 3. A lumber product according to any one of claims 4 to 8, for use in the manufacture of parquets, wainscoting, ceilings, staircase elements, veneers, decorative elements, panels, boards, and / or two- or multi-layer wooden materials.