EP1681143A1 - Impregnating agent, process for impregnating of dried and profiled wood, and wood product impregnated therewith - Google Patents

Abstract

The medium consists of a mixture containing at least two components from the following groups of materials; paraffin, paraffin wax, vegetable wax, vegetable oils and/or silicone wax. Two components differ in respect of their mobility, whereby the more mobile of the components tends to migrate under the anticipated ambient conditions in which the impregnated wood is to be used and the impregnation medium contains pigments and/or paint.

Description

The invention relates to an impregnating agent for dried and profiled wood, consisting of hydrophobic components. Furthermore, the invention relates to a use of the impregnating agent.

In the impregnation of wood, a distinction can basically be made between aqueous impregnating agents and pure hydrophobic impregnating agents. In the present case, it is a non-water-based hydrophobization of the wood.

From DE 198 41 433 C2 a method for producing a parquet floor and a parquet floor made herewith are known, in which the wood top layer of the parquet floor covering is impregnated or soaked in a protective agent of oil or wax. It should be created by the objective of a parquet floor, which has a much better life and durability compared to previous wood floors. Accordingly, the impregnated by the preservative wood top layer of parquet floor should form an improved abrasion protection. Due to the application of the parquet floor in the interior of a rotting protection is not realized.

The process according to US 1,572,905 is a two-step process, so that there is no uniform impregnating agent with both components in the form of a blend, but only two separate impregnating agents, namely the low impregnating agent viscous, slightly penetrating into the wood wax and a second, later applied impregnant of asphalt, has.

US Pat. No. 3,278,277 discloses an impregnating composition of coal tar oil and wax, but in this document there is also no special property tuning which coordinates the mobility of a more mobile component in conjunction with the expected environmental conditions.

The impregnating agent described in DE 297 80 342 U1 consists of a combination of resin and wax.

DE 539 391 A describes a process for the refinement of wood, in which montan wax in the molten state is pressed into the wood under high pressure. For this purpose, preferably dry wood is used, which is immersed in the heated, molten montan wax and placed in this container, preferably with 8 to 14 atmospheres under pressure. The text of the description speaks of a growth temperature of 105 ° C to 120 ° C or of 150 ° C in connection with a 3-hour application.

DE 203 10 745 U1 describes an impregnation method for wood with a wax melt.

Furthermore, DE 101 60 424 A1 discloses a treatment method by means of impregnating agent in a container system for the permanent use of wood, in which freshly beaten or still moist wood is in a pressure-resistant manner Container is surrounded by an impregnating agent consisting of at least paraffin and a superplasticizer, wherein the container is under negative pressure and the container is heated. This method is a juice displacement of wet wood with the impregnating agent, which is associated with a volume shrinkage of 10 to 15% and the process for finished, namely finished dried and profiled wood, not applicable.

Furthermore, US Pat. No. 6,596,063 B2 discloses an impregnation method for wood, in which the impregnating agent consists of a solvent-free melt with at least one component from the following substance groups, chemically modified natural resin, chemically modified natural resin acid and turpentine resin. In a further embodiment, a proportion of "wax" up to 45% (m / m) is described on the resin-based impregnating agent.

The object of the invention is to provide an impregnating agent and a use of the impregnating agent taking into account DE 198 41 433 C2, with the dried and profiled wood also protected in bar dimensions against moisture and a self-healing effect of the protection is provided in subsequently incurred cracks and / or damage.

This object is achieved with an impregnating agent consisting of a mixture of at least two components from the substance groups paraffins, paraffin waxes, vegetable waxes, vegetable oils and / or silicone waxes, in which two components differ in terms of their mobility, wherein the at least one more mobile component of the impregnating agent under the expected environmental conditions in which the impregnated wood is to be used, is capable of migration and the impregnating agent contains pigments and / or dyes.

An impregnating agent with a similar substance content is described in the post-published, prior patent application of the applicant DE 103 41 883. The special properties that cause the self-healing effect of moisture protection, are not included in the post-published font.

In the also postpublished, earlier patent application DE 10 2004 041 032 A1 a method for impregnating wood under pressure with an under pressure at least partially liquid Impägniermittel is known which consists of a less than 5% water mixture of paraffins and / or wax of different chain lengths or molecular sizes, wherein the paraffins or waxes are selected as part of the mixture so that they are at least partially solid at ambient temperatures and at least only at significantly higher temperatures, in any case above 50 ° C, liquid. A staining of the wood to be impregnated with color pigments or dyes is not described.

By selecting two components from the named substance groups, which differ with respect to their mobility, it is achieved that on a finished impregnated wood, the at least one more mobile component is still mobile, namely capable of migration, present in the wood structure. The selection of these at least one more mobile component is adapted to the expected environmental conditions, namely in particular temperature, humidity, possibly pressure conditions, etc., in which the finished wood product, for example, a window / door frame is to be used. At the same time, "migratory" means that this more mobile component is at least temporarily mobile under the ambient conditions in which the finished wood product is used. The environmental conditions at the place of use of the finished wood product are of course subject natural fluctuations. This can be the case, for example, in window / door frames, which are exposed outdoors, for example, temperatures of -20 ° C to +70 ° C (sunlight), only for a temperature range of, for example, above 35 ° C. This means that in the above example, the more mobile component at low outside temperatures (winter time) is actually not movable in the wood. When a temperature in the wood of, for example, 35 ° C is exceeded, but then the more mobile component is capable of migration, that is mobile in the wood.

When cracks and / or damage of the finished impregnated wood occurs, this more mobile component will migrate towards the crack or damage and thus achieve a self-healing effect of moisture protection due to the hydrophobizing properties of this more mobile component. Particularly in the case of microcracks, which are particularly susceptible to unwanted moisture absorption due to their capillary action, the crack with the hydrophobic material is closed again by the diffusion of the more mobile component of the impregnating agent preferably from the wood interior to the outer regions of the wood. It is essentially uncritical that at low ambient temperatures, for example in winter, the mobile component is temporarily not movable, since at low temperatures of the feared enzymatic degradation does not take place. However, as soon as the temperatures in the impregnated wood rise in the spring or in strong sunlight, the more mobile component becomes mobile and can cause the self-healing effect.

It is finished drenched and profiled wood, so finished wood impregnated with the impregnating agent. In this case, dried wood means that the wood is present with a maximum wood moisture below the fiber saturation. The term profiled is intended to state that the wooden components in Final format, so are finished and require no subsequent surface finishing more. It is therefore preferably technically dried, profiled, so finished wood, which is not reworked after the impregnation process, so in particular learns no after-treatment. The dried wood easily absorbs the paraffins, waxes, etc. The individual fibers and / or cells of the wood are coated / encased by the hydrophobic substances. This hydrophobing produces an effective moisture protection. Thus, the wood is optimally protected by the substantially complete impregnation against rot and rotting. The wood protection effect against biological degradation is achieved exclusively by the hydrophobization. The protection against rotting of the wood is achieved completely without the addition of fungicides or insecticides.

However, this hydrophobing does not lead to a dimensional change of the wood, since it completely dispenses with aqueous components in the impregnating agent. Swelling of the wood fibers and / or cells is thus avoided, so that a post-processing of the finished wood after impregnation is not required. The Imrägniermittel thus a significant production simplification is achieved, since only finished wood impregnated in one operation and treated in color.

A further advantage is that the impregnation of the wood to be impregnated with the impregnating agent can be carried out at relatively low temperatures of below 160 ° Celsius, preferably up to 130 ° Celsius. Therefore occur in this minor thermal stress on the wood no loss of strength of the wood texture. By impregnating the wood with the impregnating agents, the stability of the wood can even be improved can be improved because the complete impregnation of the wood with the impregnating acts more like a supporting matrix.

Furthermore, it is advantageous that the mixtures of the impregnating agent from the mentioned substance groups are also odorless and toxic harmless.

Preferably, the impregnating agent contains pigments which provide effective UV protection. In this case, pigments of their structure opaque, mineral particles, which are often used as UV protection. The UV protection is intended in particular to protect against photodegradation and depolymerization in and on the impregnated wood. Accordingly, the UV protection is defined in particular as protection against photodegradation and / or depolymerization, i. H. The fiber or cell structure of the wood is protected against UV exposure.

The pigments furthermore preferably have a particle size of less than 10 .mu.m, in particular in a distribution between 0.05 .mu.m and 10 .mu.m . This ensures that the pigments suspended in the impregnating agent are distributed as follows: the pigments of large particle size lie essentially on the wood surface; however, the small particle size pigments (micropigments) also penetrate deeper into the interior of the wood and thus cause pigmentation and a prepared UV protection in the wood interior, if subsequent damage and / or cracks occur or a reworking of the wood should be required.

In addition, a self-healing effect of the UV protection is achieved by the pigments suspended in the impregnating agent and there in the more mobile components of the impregnating agent. With the mobile component, which is still capable of being migrated under ambient conditions in the later installed state, the components which are suspended therein are suspended Moving pigments with this "liquid". This migration process means that subsequent damage and / or cracks in the wood are coated with this more mobile component and consequently also deposits pigments on the newly created surfaces, which lead to an effective "subsequently self-contained" UV protection.

As an alternative to the pigments or in addition, the impregnating agent contains dyes. The dyes are present as chemically dissolved substances. Unlike pigments, dyes are less UV resistant.

The dyes are preferably water-insoluble, ie fat-soluble, in order to achieve a uniform dyeing of the impregnating agent and thus of the wood saturated with the impregnating agent. The complete staining of the impregnated wood can be used as an indicator of the fully achieved wood preservation, namely complete impregnation of the wood. If, for example, a finished wood is still severed after the impregnation, the dye dissolved in the impregnating agent visualizes the penetration depth or the complete impregnation of the wood with the impregnating agent.

It is particularly preferred that the mixture contains at least 80% (m / m) of synthetic and / or mineral oil-derived paraffins, paraffin waxes and / or silicone waxes and up to 20% (m / m) vegetable waxes and / or oils. This maximum proportion of natural (vegetable) waxes and / or oils prevents the impregnating agent from being colonized, degraded and / or discolored by organisms, which otherwise occurs very rapidly in the case of natural oils in the form of blackening due to fungi and / or bacteria would. Here are meant synthetic and / or mineral oil-derived paraffins and / or paraffin wax unsaponifiable waxes. In contrast, the vegetable waxes and / or oils are saponifiable.

The fact that the at least one more mobile component has a lower melting point and / or a lower viscosity than the other components, the increased mobility of this component is achieved due to the said physical properties. Preferably, the more mobile component paraffin waxes having a melting point less than 60 ° C and the other component paraffin waxes having a melting point greater than 60 ° C, preferably 70 ° C to 105 ° C. For example, the more mobile component may have a melting point of 35 ° C to 45 ° C, so that the mobile component in outdoor conditions usual in our latitudes, at least in the summer time is mobile, that is capable of migration. In this case, the melting point of the more mobile component should also be chosen in accordance with the color of the impregnated wood, since dark shades cause a higher surface temperature when exposed to sunlight, so that thus selected for darker shades a rather higher melting point for the more mobile component, for example, about 45 ° C. should be. Of course, other physico-chemical properties, such as the relative humidity and / or the ambient pressure, of a component of the impregnating agent can lead to the required increased mobility.

In a further embodiment, the components of the impregnating agent have a melting point of 35 ° C to 135 ° C, preferably 40 ° C to 105 ° C. This applies both to the main components of the impregnating agent from the substance groups paraffins, paraffin waxes, vegetable waxes, vegetable oils and / or silicone waxes, as well as any additives. For example, for certain applications, the addition of fungicides and / or biocides may be beneficial, as some wood discoloring or soil modifying organisms may not be completely displaced by the major components of the saturant from settling on the wood.

If the at least one more mobile component comprises less than 50% (m / m), preferably less than 30% (m / m) of the substance mixture, the non-mobile components of the impregnating agent will achieve sufficient grip and abrasion resistance of the impregnation and bleed out the lower ones Viscous component effectively prevented. The more mobile component is thus held by the less mobile component due to the chemical / material affinity.

The impregnating agent is preferably applied in one stage with a treatment time of 30 minutes to 12 hours. One-stage means that the wood to be treated is introduced only once into a treatment tank and removed again after treatment. The duration of treatment is to be selected depending on the material thickness of the solid wood to be impregnated, timber component or wood material and the type of wood. In particular, the temperature during the impregnation treatment and the pressure conditions play a decisive role.

In a preferred embodiment, a single-stage treatment in a temperature range below 180 ° C, preferably from 60 ° C to 160 ° C, in particular from 80 ° C to 130 ° C. If possible, a temperature below 160 ° C should be chosen, as above 160 ° C, the wood structure is attacked, which leads to losses in strength.

For special applications, however, the wood is subjected to a heat treatment at least 160 ° C for at least 2 h, preferably at least 4 h. With this heat treatment, an increase in the durability of the material against attack by termites and marine organisms, especially against the highly destructive shell (teredo navalis) is achieved at the expense of losses in strength. The impregnating agent serves as a medium for the heat input.

In this heat treatment, a part of the wood material gasifies, so that gas leakage occurs from the wood during the heat treatment.

Accordingly, the final impregnation is preferably carried out only after the heat treatment in a second phase of the process. The impregnating agent then need not be introduced or held against the gas pressure of the exiting gasifying wood substance in the wood. In addition, the gases present in the wood on cooling, for example, from 160 ° C to 80 ° C together and support the impregnation with the impregnating agent in the subsequent impregnation phase, which may also be supported by external pressure.

In an impregnation treatment with elevated temperature, for example 80 ° C to 180 ° C, a warming-up stage is preferably carried out in which a temperature difference of the internal wood temperature to the impregnating agent temperature of 30 ° C is not exceeded.

In a further embodiment, a treatment stage may be formed in which the internal wood temperature corresponds to the impregnating agent temperature. In this treatment stage, a very high mobility of the impregnating agent, ie a very strong impregnation of the wood can be achieved.

In order to prevent unwanted blistering on the surface of the already finished wood parts, a cooling step may be provided, in which the wood is cooled so slowly that dissolved in the wood interior released gases and / or wood gases and washed out.

Furthermore, the single-stage treatment should be carried out in a pressure range of 20 mbar to 50 bar. It is quite conceivable that the applied external pressure is changed during the impregnation treatment. For example, initially via the atmospheric pressure increased gas pressure be applied to the wood to be impregnated to allow the impregnating agent to subsequently penetrate into the wood. At the end of the treatment, a reduced pressure, for example also below atmospheric pressure, may result in a desired outgassing and associated partial recovery of the saturant (sparging process) during the cooling step.

Embodiments of the invention will now be described with reference to an experimental procedure with reference to two figures.

example 1

D: 99.5 parts of Fischer-Tropsch paraffin, Paraflint C105 (Sasol Wax GmbH, Hamburg), empirical formula: (C _n H _{2n + 2} ); Solidification range:> 90 ° C 0.5 parts of solid, saturated hydrocarbons, TerHell Paraffin 3496 (Sasol Wax GmbH, Hamburg), empirical formula: (CnH _{2n + 2} ); Solidification range:> 35 ° C; Viscosity at 100 ° C (DIN 51 562): 2.5 - 10 mm ² / s 0.5% (m / m) of fine pigment dispersed, Bekro 401 red (Bekro Chemie GmbH) 0.5% (m / m) of dye red (Bekro Chemie GmbH)

Example 2

DA5: 95 parts of Fischer-Tropsch paraffin, Paraflint C105 (Sasol Wax GmbH, Hamburg), empirical formula: (C _n H _{2n + 2} ); Solidification range:> 90 ° C 5 parts of solid, saturated hydrocarbons, TerHell Paraffin 3496 (Sasol Wax GmbH, Hamburg), empirical formula: (C _n H _{2n + 2} ); Solidification range:> 35 ° C; Viscosity at 100 ° C (DIN 51 562): 2.5 - 10 mm ² / s 0.5% (m / m) of fine pigment dispersed, Bekro 401 red (Bekro Chemie GmbH) 0.5% (m / m) of dye red (Bekro Chemie GmbH)

Example 3

DA30: 70 parts of Fischer-Tropsch paraffin, Paraflint C105 (Sasol Wax GmbH, Hamburg), empirical formula: (CnH2n + 2); Solidification range:> 90 ° C 30 parts of solid, saturated hydrocarbons, TerHell Paraffin 3496 (Sasol Wax GmbH, Hamburg), empirical formula: (CnH 2n + 2); Solidification range:> 35 ° C; Viscosity at 100 ° C (DIN 51 562): 2.5 - 10 mm ² / s 0.5% (m / m) of fine pigment dispersed, Bekro 401 red (Bekro Chemie GmbH) 0.5% (m / m) of dye red (Bekro Chemie GmbH)

Used wood:

Kiefer Splint ( Pinus sylvestris L.) was investigated for the penetration test of the impregnating agent and the associated moisture protection success. used in the dimension 500x50x25 mm ³ . The technically dried pine split wood originated from the BFH stocks and was stored in the thickness planer after cutting and cutting surface processing until the equilibrium weight was reached in the standard climate (20 ° C./65% relative air humidity). After the weight constancy of the impregnated samples in standard atmosphere (20 ° C./65% relative humidity) was reached, the impregnation process was carried out using the respective impregnating solution from Examples 1, 2 and 3.

impregnation:

Process temperature in the drinking vessel 138 ° C Imprägniermitteltemperatur 126 ° C Wood interior temperature 125 ° C Pressure phase at 8.0 bar absolute 3.25 h Vacuum phase at 20 mbar absolute 1.25 h Cooling phase up to 80 ° C 2.25 h Total duration of the impregnation process: 6,75h

Achieved intake levels and optically determined penetration of the impregnating agent: <b> Table 1. Average intake and penetration of impregnant over the total cross-section of the separated samples </ b> impregnating Intake in kg / m ³ optically definite penetration example 1 361 100% Example 2 365 100% Example 3 376 100%

Determination of moisture protection

It was the moisture risk, or the moisture protection determined by the impregnation. After exposure in standard atmosphere (20 ° C./65% relative humidity) until the weight constancy was reached, the impregnated samples were stored immersed in water for seven days. During this water absorption phase, the wood moisture was determined gravimetrically daily and the water absorption rate was calculated when the boundary moisture exceeded 25%. Subsequently, the impregnated samples were exposed for seven days in calibrated wind tunnels in standard atmosphere (20 ° C / 65% relative humidity). Daily the wood moisture was determined gravimetrically during this steam desorption phase and the water vapor release rate was calculated when the moisture content fell below 25%. Based on the rate of desorption and desorption, the risk of moisture-induced infestation by wood-destroying organisms (MRI = Moisture Induced Risk Index) was calculated. The results of the determination of the moisture protection are shown in Figure 1, Figure 2 and Table 2.

The combination of two different viscous paraffins reduced the moisture absorption compared to untreated pine splint (Figure 1 and Figure 2), thus effectively achieving moisture protection. This is also expressed in a reduced moisture-induced risk of infection by wood-destroying organisms ( error! Reference source could not be found .). The lower the MRI value, the lower the moisture-induced risk of infection. <b> Table 2. Velocity of wood moisture change and calculated MRI value </ b> impregnating Wood moisture change in the point 25% wood moisture during MRI absorption desorption control 11.900% / h 1,100% / h 2,325 example 1 0.120% / h 1,160% / h 0,095 Example 2 0.120% / h 1.580% / h 0.072 Example 3 0.055% / h 1,300% / h 0,041

Determination of the UV resistance of the surface

For the determination of the UV resistance, the samples impregnated with the impregnating solutions from Examples 1, 2 and 3 as well as untreated controls were irradiated for 168 h with 300 W Ultra-Vitalux lamps from Osram. The distance of the lamps to the sample surface was 30cm. The color change of the outside of the samples as well as the color change of the cut surface after central separation were investigated. The color change was evaluated by viewing the digitized CMY values (cyan magenta yellow). The evaluation was carried out by calculating the percentage change in color after irradiation. The results are in error! Reference source could not be found . shown. <b> Table 3. Percent color change due to UV irradiation. Positive signs signify a subsequent darkening, negative signs a clearing of the color value </ b> impregnating outside section control -141.2 -142.0 example 1 4.6 -6.4 Example 2 1.5 -2.5 Example 3 1.2 0.8

Claims (9)

Impregnating agent for finished, dried wood, consisting of a mixture of at least two components from the groups of substances - paraffins, - paraffin waxes, - vegetable waxes, - vegetable oils and / or - silicone waxes, characterized in that two components differ in terms of their mobility, wherein the at least one more mobile component of the impregnating agent is capable of migration under the expected environmental conditions in which the impregnated wood is to be used, and in that the impregnating agent contains pigments and / or dyes. Impregnating agent according to claim 1, characterized in that the mixture contains at least 80% (m / m) of synthetic and / or mineral oil-derived paraffins, paraffin waxes and / or silicone waxes and up to 20% (m / m) vegetable waxes and / or oils. Impregnating agent according to claim 1 or 2, characterized in that the dyes are water-insoluble, ie fat-soluble. Impregnating agent according to claim 1, 2 or 3, characterized in that the pigments have a particle size in a distribution between 0.05 .mu.m and 10 .mu.m. Impregnating agent according to claim 2, 3 or 4, characterized in that the more mobile component paraffin waxes having a melting point less than 60 ° C and the other component paraffin waxes having a melting point greater than 60 ° C, preferably 70 ° C to 105 ° C. Impregnating agent according to one of the preceding claims, characterized in that the at least one more mobile component less than 50% (m / m), preferably less than 30% (m / m) of the mixture comprises. Use of the impregnating agent according to any one of claims 1 to 6 for impregnating finished, dried wood, wherein the wood is impregnated with the impregnating agent. Use according to claim 7 with a pigment of different particle size-containing impregnating agent, characterized in that the pigments suspend in the impregnating agent, wherein the pigments of large particle size substantially rest on the wood surface, the pigments small particle size also penetrate into the wood interior and subsequent damage and / or Cracks migrate the pigments in suspension with the more mobile components. Use according to claim 7 or 8, characterized in that the wood is completely dyed by means of the fat-soluble dyes mixed in the impregnating agent, wherein the dye dissolved in the at least one more mobile component migrates with this component.

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