DE102008040903A1 - Wood pieces i.e. parquet tiles, coloring method for parquet floor, involves applying and maintaining high pressure in color fluid and wood pieces, and pumping color fluid and applying and maintaining low pressure over time period - Google Patents

Abstract

The method involves introducing wood pieces (1) in a pressure chamber (2), and pumping of a pretreatment liquid (9) e.g. alcohol, and applying and maintaining low pressure over a time period. A color fluid is applied into a pressure chamber so that wood pieces provided in the pressure chamber are completely surrounded by the color fluid. High pressure in the color fluid and the wood pieces is applied and maintained over the time period. The color fluid is pumped and the low pressure is applied and maintained over the time period. An independent claim is also included for a device for coloring wood pieces.

Description

The The invention relates to a method of dyeing Wood, in particular for pieces of wood, for example for floors such as parquet floors, as well on a parquet floor of such pieces of wood.

colored Pieces of wood are used in the manufacture of furniture, Musical instruments, toys and many other products since used for many years. Here are a variety of methods for Use, such as coatings, stains and dyes. However, with the dyeing process from the state of the Technique only dyeings on the surface the dyed piece of wood possible. So For example, in paint finishes, a layer of paint on the surface applied to the piece of wood. This changed on the one hand the haptic appearance of the pieces of wood, something is often not desired, and the other is Such a coating against surface damage extremely sensitive. This makes lacquered pieces of wood suitable Not for use on floors caused by Traffic load prone to minor damage the surface are.

With Although pickling can change the color of the wood, However, the penetration depth is limited and the natural Color of the wood can only be changed slightly. at Surfaces exposed to increased loads are, it is common to do this in regular Distances by grinding or removal of the uppermost, used surface layers again optically produce. This is problematic in pickled pieces of wood, as by abrading the colored surface layers the color is completely or partially removed and thus the visual impression is impaired.

Similar Problems occur when using colored pieces of wood on. In the usual dyeing methods are only colored a few fractions of millimeters of the wood surface, so that recognizes the real wood color in case of damage is. Even a grinding is due to the low penetration depth the color layer not possible.

The DE 439 226 describes a method of staining wood using high pressure and cooking temperature. However, not all woods are suitable for the high temperatures encountered in this process and the softening of the core areas by the high temperatures reduces the strength that is important for use as floors.

In the EP 1 073 547 discloses a method of staining wood using pressures in excess of 800 bar. When using such high pressures, the wood is first compressed and introduced in a further step in Färbeflüssigkeit, whereby the compressed in the first high-pressure step wood cells swell again and thereby absorb the dyeing liquid. However, because of the high pressures required, this process is very costly, and the strength and resilience of the dyed wood is significantly affected by the squeezing and subsequent swelling of the wood.

It There is therefore a need to provide a method for through-coloring of wood to provide the strength of the Wood is not negatively affected, is inexpensive and to stain the wood to a depth of at least one centimeter. This is achieved with a wood dyeing process according to claim 1 and the pretreatment method according to claim 9. Advantageous Further developments of the method emerge from the dependent claims.

to Implementation of the wood dyeing process according to the invention The pieces of wood to be dyed are air-dry introduced into a printing / dyeing chamber. Optional may be before the introduction into the printing / dyeing chamber, a warming of wood in a climatic chamber, so that the wood pores open become. In the printing / dyeing chamber, the wood becomes with stacking strips set up so that it is completely absorbed by the fluids, used in the process of treating the pieces of wood can be flown around. To prepare the pretreatment can now be a vacuum or a negative pressure in the printing / dyeing chamber generated by the air and residual moisture present the wood pores is pulled. Due to this negative pressure, which is reflected in the interior of the wood spreads, is in the further process steps facilitates the penetration of the treatment liquids.

The Duration of the vacuum or vacuum treatment is the same as the one used Vacuum or the vacuum of the treated wood and the Pre-condition of the wood dependent. In general, the Duration of the vacuum treatment in the range between 0.5 and 10 hours, at a pressure of -0.7 to -0.99 bar, based to the atmospheric pressure. For most types of wood vacuum treatments are sufficient with a duration of 1 to 6 hours.

Subsequent to the vacuum treatment, the printing / dyeing chamber is filled with a pretreatment liquid. This pre-treatment liquid is used to dissolve resins and wood ingredients from the wood pores and make the wood so receptive to the dyeing liquor. Accordingly, the pre-treatment liquid contains a solvent. As solvents come in dependency For example, acids from the type of wood to be treated, such as acids, alkalis or alcoholic solvents in question, with alcoholic solvents are problematic because of the risk of ignition. The solvents therefore preferably consist of an aqueous, non-combustible solution, in particular an acid or alkali. For example, citric acid is suitable for the pretreatment of maple wood, while oak is preferably oxalic acid used.

In order to the pre-treatment liquid penetrates deeply into the interior of the wood can now be an overpressure on the pre-treatment liquid applied in the printing / dyeing chamber. This overpressure is maximum 100 bar, but in most cases are Press in a range of 5 to 50 bar sufficient to a satisfactory penetration depth with an acceptable treatment time, the ranging from 6 to 96 hours. With a pressure in the range between 10 and 15 bar can be at a relatively inexpensive printing / dyeing chamber assembly and not overly lengthened Treatment duration in a range of 12 to 48 hours for most wood species achieve good pre-treatment.

In order to the pre-treatment can be done efficiently, the overpressure is over maintain the duration of treatment. As the pretreatment fluid penetrates into the interior of the wood during the treatment and thus a pressure loss takes place, pretreatment liquid must be pumped over the entire treatment period so as to keep the pressure substantially constant. alternative is it possible to improve one's penetration or perform several pressure / relaxation cycles. there is after a part of the treatment period, for example after 2 Hours, for a shorter time, for example 0.5 hours, the pressure in the pressure / dyeing chamber degraded, so as to allow the wood to relax. By the Relaxation process "pulls" the wood, always still completely in the pre-treatment liquid immersed, additional pre-treatment liquid into the wood interior, so that the pretreatment effect is enhanced becomes.

To pretreatment is the pretreatment liquid pumped out and carried out a new vacuum / vacuum treatment. By the re-vacuum / vacuum treatment becomes the pre-treatment liquid pulled out of the wood pores and prepared the wood for the dyeing treatment. The basic process steps in the vacuum / vacuum treatment correspond to the process steps already before the pretreatment the duration of the vacuum / vacuum treatment and / or the vacuum used or the vacuum of the first performed Vacuum / vacuum treatment may differ.

When Next step is the wood in the dyeing liquor brought in. Depending on the existing system and needs The dyeing step can be done in the same printing / dyeing chamber like the pretreatment or in a special, dedicated dyeing chamber be performed. It is not absolutely necessary that the dyeing process immediately after the pretreatment rather, the wood may be between pretreatment and dyeing treatment stored intermediately and / or additionally be dried.

The Wood is in the dyeing chamber analogous to the pretreatment so put it on all sides of the pretreatment fluid can be flown around. Then the dyeing liquid introduced and also subjected to an overpressure. The pressure ranges and the treatment time for dyeing are basically the same as those for pretreatment, i. H. the pressure used is a maximum of 100 bar, as a rule between 5 and 50 bar, and can be used in most cases Range of 10 to 15 bar are kept what the system costs reduced. The duration is analogous to the pretreatment 6 to 96 hours, taking for most woods and wood thicknesses a period of 12 to 48 hours is adequate and sufficient. But it is not necessary that the dyeing treatment same pressures, durations and procedures as in the pretreatment. Rather, they are Process parameters of the dyeing step independently from the process parameters of the pretreatment step and among other things by type of wood, size of the pieces of wood to be dyed, Color and color solvents influenced.

As in the pre-treatment can also be the coloring step by one or more pressure / relaxation cycles supported become. These pressure / relaxation cycles become analogous to the cycles executed during the pretreatment, again with the parameters such as number, pressure and duration of the cycles of those of the pretreatment may differ.

Subsequently The dyeing step is followed by the dyeing liquor pumped out of the pressure / dyeing chamber and again a vacuum / vacuum applied to the dyed pieces of wood to residual dyeing liquid to remove from the wood and a pre-dried wood condition to reach. The dyed woods can then be further processed. A particularly preferred application for through-colored according to the invention Hölzer is the production of parquet friezes for Parquet floors.

In a modified procedure it is possible, especially for woods that are particularly difficult to color due to their structure, to perform more than one pre-treatment cycle and / or more than one staining cycle. In particular, different solvents can be used in the pretreatment cycles in order to combine advantages of these solvents. The same is possible with different colorants.

Further Features, feature combinations, features and benefits of Invention will be more apparent from the following description of a preferred embodiment and the figure. This shows in:

1 A plant for carrying out the method according to the invention.

1 shows a plant for dyeing wood, which is suitable for the inventive method. The wood to be dyed 1 , for example beech wood, is stacked in the pressure chamber 2 brought in. About the supply line 3 Warm air can be added to the wood 1 unlock before treatment and expand the wood pores. After the line 3 is closed, is over the line 4 with the valve open 5 and closed valve 6 by means of the vacuum pump 7 via the vacuum template 8th in the pressure vessel 2 creates a vacuum or a negative pressure. This vacuum will now be maintained for several hours. For the above-mentioned beech wood, a vacuum cycle of about 2 hours at -0.9 bar is provided.

After completion of the vacuum cycle, the pressure vessel 2 with the pretreatment fluid 9 , in the case of beech wood filled with tannic acid. This fluid is in a separate container 10 and is over the line 11 , the valve 12 , the pressure pump 13 and the valves 14 . 6 with the line 4 leading to the pressure vessel 2 leads, connected. For filling the pressure vessel is therefore now the valve 5 closed and the valves 12 . 14 and 6 open. Due to the pressure prevailing in the pressure vessel, this now fills, the pressure pump 13 to assist in filling and, after complete filling, to build up the pretreatment pressure. The desired pressure, with beech wood approx. 14 bar, is achieved via the pressure regulating valve 15 set. As soon as the pressure in the boiler exceeds the desired pressure, the pressure regulating valve opens 15 and the excess pretreatment liquid is passed over the line 16 and the valve 17 in the container 10 recycled.

The pressure is now maintained for a certain time, in the case of beech wood for 7 to 8 hours. To improve the absorption of the pretreatment fluid, the pressure is released approximately every 2 hours and then reapplied. At the end of the pretreatment period, the pre-treatment liquid is transferred via the line 18 and the valve 20 by means of the pressure pump 19 back in the container 10 pumped.

In the 1 shown system knows another container 21 on that over the valve 22 with the line 11 , over the valve 23 with the line 16 and over the valve 24 with the line 18 connected is. This container 21 may contain a second pretreatment liquid and is used analogously to the pretreatment described above, if a second pretreatment cycle with a different pretreatment liquid is necessary. For beech wood, treatment with tannic acid is sufficient.

After the pretreatment liquid has been pumped off, another vacuum / vacuum cycle is carried out analogously to the one described above. The valve 6 will be closed again and over the line 4 , the valve 5 and the vacuum pump 7 creates a new vacuum.

After the excess pretreatment liquid has been removed from the wood by means of the second vacuum cycle, the actual dyeing can be continued in the next step. The dyeing liquid, for beech wood a 5% iron sulfate solution with about 1% dye content, from the container 25 is over the valve 26 , The administration 11 and the pressure pump 13 pumped into the pressure vessel and then applied the dyeing pressure, in the example with beech wood again 14 bar. This pressure will be maintained again for a certain time, for beech wood for 24 hours. Again, regular relaxation / pressure cycles can be made to aid penetration of the dye into the wood. In the example with beech wood, the cycle time for such a relaxation / pressure cycle is about 4 hours.

After completion of the dyeing treatment, the dyeing liquid is pumped 19 over the line 18 and the valve 28 in the container 25 pumped back.

Subsequently, a post-vacuum for pre-drying the wood by means of the vacuum pump 7 on the pieces of wood 1 be applied. In the present example with beech wood this vacuum of -0.9 bar is maintained for 2 hours before the wood is removed from the pressure vessel and spent for further technical processing.

To control the pressure and / or the spent pretreatment and / or dyeing liquid is in the line 11 a measuring instrument 29 is introduced. This can be checked during the pretreatment and / or dyeing process, the pressure and be inferred from the liquid flow, whether the wood has already absorbed enough liquid.

It is obvious that the pressure values mentioned and Cycle times have merely exemplary character and depending on used wood species, pretreatment and other parameters accordingly need to be adjusted.

1

pieces of wood

2

pressure vessel

3

Warm air supply

4

management

5

Valve

6

Valve

7

vacuum pump

8th

vacuum template

9

pretreatment liquid

10

container

11

management

12

Valve

13

pressure pump

14

Valve

15

Pressure control valve

16

management

17

Valve

18

management

19

pressure pump

20

Valve

21

container

22

Valve

23

Valve

24

Valve

25

container

26

Valve

27

Valve

28

Valve

29

gauge

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 439226 [0005]
• EP 1073547 [0006]

Claims (17)

Process for dyeing pieces of wood, in which a dye liquor with the aid of pressure / vacuum and / or temperature into the interior of a piece of wood ( 1 ), the method comprising the following steps: a) introducing the pieces of wood into a printing / dyeing chamber ( 2 ); b) applying and maintaining negative pressure for a certain period of time; c) introducing a pretreatment liquid ( 9 ) into the printing / dyeing chamber ( 2 ), so that in the printing / dyeing chamber ( 2 ) pieces of wood ( 1 ) completely from the pretreatment liquid ( 9 ) are surrounded; d) application and maintenance of an overpressure on the pretreatment liquid ( 9 ) and in the printing / dyeing chamber ( 2 ) pieces of wood ( 1 ) over a certain period of time; e) pumping out the pretreatment fluid ( 9 ) and applying and maintaining a negative pressure for a certain period of time; f) optionally repeating steps d) and e) until a desired pretreatment condition has occurred; g) introducing a dyeing liquid into the printing / dyeing chamber ( 2 ), so that in the printing / dyeing chamber ( 2 ) pieces of wood ( 1 ) are completely surrounded by the dyeing liquor; h) application and maintenance of an overpressure on the dyeing liquor and in the printing / dyeing chamber ( 2 ) pieces of wood ( 1 ) over a certain period of time; i) pumping out the dyeing liquor and applying and maintaining a vacuum for a certain period of time; j) optionally repeating steps h) and i) until the desired degree of staining has been achieved. Method according to claim 1, characterized in that the pieces of wood ( 1 ) are completely colored. Method according to claim 1 or 2, characterized that in steps b), d), e), f), h), i) and / or j) the sub- or overpressure within the treatment step or relaxed several times and then reapplied becomes. Method according to one of the preceding claims, characterized in that the negative pressure -0.7 to -0.99 bar, based on the atmospheric pressure. Method according to one of the preceding claims, characterized in that the overpressure is 5 to 100 bar, preferably 5 to 50 bar, particularly preferably 10 to 15 bar, based on the atmospheric pressure. Method according to one of the preceding claims, characterized in that the pretreatment liquid a solvent, preferably an aqueous solvent, in particular an acid, alkali or alcohols. Method according to one of the preceding claims, characterized in that the pressure phases have a length from 6 to 96 hours, preferably 12 to 48 hours. Method according to one of the preceding claims, characterized in that the vacuum phases have a length from 0.5 to 10 hours, preferably 1 to 6 hours. Process for the pretreatment of wood ( 1 ) for a dyeing process, characterized by the following steps: a) introduction of the pieces of wood ( 1 ) in a printing / dyeing chamber (2); b) applying and maintaining negative pressure for a certain period of time; c) introducing a pretreatment liquid ( 9 ) into the printing / dyeing chamber ( 2 ), so that in the printing / dyeing chamber (2) located pieces of wood ( 1 ) completely from the pretreatment liquid ( 9 ) are surrounded; d) application and maintenance of an overpressure on the pretreatment liquid ( 9 ) and the pieces of wood in the printing / dyeing chamber (2) ( 1 ) over a certain period of time; e) pumping out the pretreatment fluid ( 9 ) and applying and maintaining a negative pressure for a certain period of time; f) optionally repeating steps d) and e) until a desired pretreatment state has occurred. Method according to claim 9, characterized in that that in steps b), d), e), f), h), i) and / or j) the sub- or overpressure within the treatment step or relaxed several times and then reapplied becomes. Method according to one of the preceding claims, characterized in that the negative pressure -0.7 to -0.99 bar, based on the atmospheric pressure. Method according to one of the preceding claims, characterized in that the overpressure is 5 to 100 bar, preferably 5 to 50 bar, particularly preferably 10 to 15 bar, based on the atmospheric pressure. Method according to one of the preceding claims, characterized in that the pretreatment liquid is a solvent, preferably an aqueous solvent, in particular a Acid, alkali or alcohols. Method according to one of the preceding claims, characterized in that the pressure phases have a length from 6 to 96 hours, preferably 12 to 48 hours. Method according to one of the preceding claims, characterized in that the vacuum phases have a length from 0.5 to 10 hours, preferably 1 to 6 hours. Device for coloring wood according to one of the preceding claims, comprising a printing / dyeing chamber ( 2 ) for receiving wood and liquids, a pressure pump ( 13 ) for applying an application pressure to the pieces of wood contained in the printing / dyeing chamber ( 1 ) and liquids ( 9 ), a vacuum pump for applying a vacuum or negative pressure to the in the printing / dyeing chamber ( 2 ), a container ( 25 ) with dyeing liquid, inlets and outlets ( 11 . 16 . 18 ) to direct the dyeing liquor to the pressure vessel and to discharge again, characterized in that at least one further container ( 10 . 21 ) for a pretreatment liquid by means of inlets and outlets ( 11 . 16 . 18 ) with the pressure / dyeing chamber and the pressure pump ( 13 ) connected is. Parquet flooring made of parquet friezes, characterized that the parquet friezes with a method according to one of the preceding Claims are colored through.