AU9341201A - Technology for producing aesthetic-quality logs from common timbers - Google Patents

Description

Original Complete Specification for Standard Patent Invention Title: Technology For Producing Aesthetic-Quality Logs From Common Timbers (The following is a full description of this invention, including the best method of performing known to me.) TECHNOLOGY FOR PRODUCING AESTHETIC-QUALITY LOGS FROM COMMON TIMBERS 1. Field of invention In the furniture and woodworking industries, thin slices of wood, commonly termed veneer, are used to cover structural wooden elements, thus improving the appearance of the original timber. Manufacturing of eneer necessitates certain tree species, indigenous or exotic, with a pleasing color or pattern, or with a contrast between sapwood and heartwood, evidenced in the industry through special log cutting techniques. Normally, the common tree species, with uniformly colored wood, are not used for veneer manufacture, being employed mainly in lower-value applications, such as building frames or as firewood.

The present description details a new technology for aesthetization of common timber species, thus allowing for manufacturing of aesthetic-quality veneer from a much cheaper, widely-available resource: the timber of various tree species, generally used for lumber or fuelwood. In addition to a novel technique employed to reveal the natural texture of these species, this invention covers also a distinctive way to combine various colored or natural timbers in a new manner, resulting in a new product: polychrome veneer, and significantly increasing the productivity of the slic,-.'j operation.

2. Background of invention Currently, due to severely declining supplies on the world markets for exotic species, habitually used for veneer manufacturing, the timber of tree species that have a naturally pleasing texture, color, or both, is available only in a limited choice and at much higher prices than in the immediate past, 3 6 decades ago.

Traditionally, the high-quality logs for the manufacturing of veneer, have been obtained from tree species growing spontaneously in the tropical or equatorial regions of Africa, Asia and South America. Due tc sxce sive i.xploitation: of this resource in this century, as well as owing to the lack of .:onrcerr, securing tile natural regeneration, presently, the few countries known traditionally as exporters of veneer-quality logs have exhausted their reserves; the price of select logs has increased significantly, the choice is limited and the dimensions of logs are much reduced. As a result, the productivity of machinery in the furniture industry has diminished while the price of furniture increases in step with the price of exotic logs.

In search for veneer substitutes, various furniture producers around the world have replaced the veneerwith other materials (printed paper or patterned plastic sheets) or have switched to the production of non-veneered furniture (such as knotty pine, rattan, etc.), which are appreciated on some markets. At the lower end of furniture quality, the manufacturers use to paint the wood in dark colors, usually hues of brown, thus obscuring the texture or color of the original material. Although widely accepted in some countries due to the lack of genuine veneer, all these solutions are considered inferior in comparison to applying genuine aesthetic-quality veneer, the demand of which remains strong.

Therefore, at this point in time, a procedure able to con',.vy aesthetic qualities to common species, in colors similar to those of exotic species or in completely new colors, non-existent in the nature, will represent a necessary and essential upgrading of timber use and the creation of a new resource.

3. The prior art and its deficiencies Essentially, there is no prior art in this field. The demand for reasonably priced veneer is practically new, owing to the recent depletion of tropical timber species. Since it will take a long time to re-create this resource, it is probable that the demand for aesthetic-quality veneer will remain critical for, at least, several decades, while the need for cheaper substitutes will increase in step with population growth.

Whereas there is no previous art for aesthetization of timber, there are industrial procedures widely-applied for impregnation of woods with: tar-like substances, based on forcing hot impregnants under pressure into logs, or fungicide/insecticide substances, based on immersion of logs in solutions with pest or insect killing effects.

Both these procedures use tree logs shaped for various uses, such as utility poles and railway ties. Impregnation is sought strictly for the final product, thus saving on the amount and cost of impregnation, sometimes by not treating the whole log. The procedures are used mostly for the preservation of timber to the action of biotic agents (fungi, insects) or against deterioration caused by exposure to elements. These procedures are currently in commercial use in various embodiments. Except for immr-rsion of logs, which is exceedingly slow and achieves only a surface treatment, no known method of impregnation succeeds without pressure being applied at one end of the log and without heating the impregnant, to decrease its viscosity.

A common problem of impregnation based on pressure is the exposure of workers to the dangers inherent in handling impregnants (usually tar-based, cancer causing substances), as well as to pressure. In addition, all together these procedures are not environmentally friendly.

Therefore, it can be stated that no procedure of aesthetization is currently applied to timber. The painting of low-quality, non-veneered furniture and wood panelling does not qualify as timber aesthetization. It is practised with either water soluble dyes, usually resulting in a darkening of the exposed surface, or with oil-based paints that completely hide the natural timber texture. Both procedures are applied with brushes over the whole surface of the material; application is uniform and usually occurs over the finite product.

With the first procedure, the anatomic elements of the wood may remain visible, but the uniform dye application over the surface reduces much of the natural contrast of the elements of wood anatomy. The second procedure, which involves applying an opaque paint, sometimes in several layers, completely obscures the wood texture.

Prior art achieves impregnation of logs for completely different aims, using complicate installations and substances that may be harmful.

4. Summary of invention A new technology that achieves the coloration of the sap-conducting cross-section of the stem has been conceived (main) and tested. Also, a procedure to assemble natural or colored logs in a block of reconstituted wood, termed here "siab," has been devised (complement). Subjecting this "slab" of wood to the slicing operation results in a sheet of veneer with uniform width, as opposed to slicing a log, where each slice results of a different width, and has to be subsequently formatted to standard dimensions, resulting in a lot of wastage. Additional advantages are avoidance of assemblage work for matching veneer patterns, possibility of combining several species in the "slab," thus resulting in an unlimited number of combinations of timber patterns and/or colors (e.g.

alternative use of natural and colored timbers when the slab is assembled), reduction of veneer wastage, caused by the different widths of each veneer sheet when logs are sliced individually, and significant increase of productivity of machinery during the slicing operation.

Main. A procedure for sending an aqueous dye solution into the sap-conducting system of a tree has been invented. It consists of sorption of a dye in the conducting elements of the stem, in order to create a contrast between these and the non-conducting ones. For the circulation of dye, the procedure uses a natural force, the suction developed in the stem as a result of the atmospheric demand for evaporation. Critical factors for obtaining a uniform and reproducible coloration are: that the dye has to be applied within a limited span of time after felling the tree, that the foliage has to remain healthy and functional until the dyeing process has ended, and that the dye solutions used are very diluted. The procedure requires that the sectioned end of tree is immersed into a reservoir with dyeing solution shortly after felling, with the foliage intact. The end of the dyeing process is marked by the coloration of leaf veins. The end result, visible only when the log is sliced, is a contrast between the remaining natural color of the non-conducting elements and the changed color of the conducting ones, reveaig the natural pattern of wood. This contrast can be obtained in a great variety of chromes and/or tones and is permanent.

The operation is performed in the forest. For average dyeing intensities, depending on tree size, the duration of the cross-section immersion into the dyeing solution is between 1 to 3 days; about one day shorter if the weather is sunny, longer if the sky is overcast. At the end of procedure, the tree is delimbed and sectioned to standard S dimensions for transport and further processing by slicing or peeling. The productivity of slicing, achieved with special cutters, currently depends on the log diameter, unless the following complements of technology are applied.

The main can be applied alone or with complements.

Complements. Complements to this technology achieve both enhancements of the aesthetic effects, enlarging the potential uses of veneer, a substantial productivity increase of the slicing operation and the elimination of sorting and assemblage of irregular veneer sheets, a tedious work phase before applying the quality veneer sheets on a solid substrate. The complements allow for the use of logs of smaller dimensions, usually not considered for aesthetic veneer production precisely because of the low productivity of slicing logs that are too thin. It can be applied either to already colored logs or to logs which are intended to remain in the natural color, or to mixtures of colored logs and logs left in the natural color. It consists of a series of operations that have to precede the slicing, such as: formatting the logs into prisms of standard dimensions, comb; the formatted prisms according to various criteria, glueing the prisms under pressure to result in a "slab," with a square or rectangular cross section and, finally, slicing of the "slab" in veneer sheets. By implementing these complements, a large variety of aesthetic combinations (species, colors, and various patterns) can be obtained, while the productivity of the slicing operation increases greatly.

In addition, adoption of these complements of the main technology opens wide possibilities for large-scale standardization in the furniture industry. Thus, the "slabs" can be produced of various dimensions, obtaining veneer sheets to match dimensionally certain furniture elements, such as: doors, tables, cabinet doors, drawers, etc. This allows for a very important reduction of wastage and a complete elimination of the assemblage of veneer slices to form a certain cover g. for a door, a table or a cabinet) which, otherwise, is a very time-consuming operation. Also, preparing the "slab" at a length that is a multiple of the length of the future veneer sheet can result in a supplementary productivity increase and wastage decrease intervention.

By achieving a cellular, indelible impregnation, that can only be destroyed by fire, this new technology allows for the creation of a new veneer resource, thus annihilating the above mentioned shortage of raw material for quality veneer. Instead of using logs of genuine, exotic species for veneer manufacture, through this procedure it is possible to use S• indigenous, lower quality timberfor aesthetic-quality uses. After treatment, the colored logs can be subjected to any of the currently-used technologies in the furniture industry for veneers of exotic species (glueing, staining, varnishing, etc). Another essential advantage, S resulting from the use of the above described complements, is that the use of thin logs for veneer production is now a distinct possibility.

Detailed description of invention The procedure that forms the core of this invention relates to use of natural processes of a living tree (crown transpiration, water absorption and movement of solutions along the sap conducting tissues) and natural forces (atmospheric demand for evaporation exerted on crown), in a novel way, unused anywhere in the world, in order to obtain a uniform, in-depth deposition of the dyeing agent on the walls of the sap-conducting elements of a tree, for obtaining a color contrast between these and the non-conducting elements of tree anatomy. Based on these principles, the procedure uses aqueous dye solutions of low concentration, which allow crown transpiration to continue until a certain, desired color saturation of stem is reached. Crucia! for the continuation of transpiration is the health of the foliage. The "discovery" consists in the finding that a fine filtration takes place in the stem of the dying tree, with the tree absorbing a dye solution through its cross section, releasing only the water vapours in the atmosphere through a foliage that continues to function several days after severance from roots, and deposing the dye in the sap-conducting elements of the tree's anatomy.

In order to reveal the pattern or texture of various tree species, traditionally considered only for non-aesthetic uses, this new technology achieves a cellular impregnation, radically different from staining or painting, with a contrast substance that does not exist naturally in the wood, as well as with other impregnants such as water-soluble preservatives. The technology uses knowledge of physiology of transpiration of cut trees in a completely new interpretation of this natural process, which runs contrary to conventional knowledge, yet has allowed its use for the aesthetization process. This invention avoids the foregoing drawbacks (see: The prior art and its deficiencies") through the fact that, in order to maintain an undiminished transpirational suction, it uses low concentration solutions of dyes.

For a short interval, at least 20 minute. after felling a tree, the foliage continues to transpire at an increased rate, due to both the atmospheric demand for transpiration (the primary suction force) and the breakage of the sap columns in the conducting tissue.

During this interval, every conducting element fills with air and acts like an embolus (a foreign body that forms an obstruction, such as an air bubble). This new procedure is based on the unique finding that, for about 20 50 minutes after the felling of a tree, which S has to be left with branches and foliage attached, cavitation (the formation and collapse of low-pressure vapour cavities in a flowing liquid) does not play a significant role, a fact which runs against established knowledge in tree physiology. After about 30 to 50 minutes, cavitation occurs, preventing otherfluids from entering the vessels. Once the foliage begins to wilt, the suction force that produced the cavitation decreases sharply. Therefore, this minute interval after felling the tree is the window of time in which the treatment has to be started. Application of the procedure at hours of the day when the atmospheric demand for evaporation is not fully developed, may extend this delay The procedure consists in immersing the cut end of a tree (basal cross section) in S a basin with the dyeing solution, as exemplified in Drawing 1. Physically, this can be organized as a buried trough (thus allowing for the impregnation of several stems with the same pigment), at the bottom of a small earth rising over which the trees are pulled by means of a manual or motorized winch, so as to have the cut end immersed into the dyeing solution. Pulling will be made with care, avoiding the plugging of the cross-section with dirt, or, if that happened, a fresh cut has to be made a few cxntimetres above the first section.

It will be noted that, for practical reasons, the p: ocedure has to be performed in the forest and that the installation required is minimal and non-polluting. Also, the velocity of the coloring process depends on the existence of a sizable atmospheric demand for evaporation, that is present only when the air temperature is at least 15 Moreover, the dyeing procedure can only be performed as long as the foliage is in place and healthy.

Selection of a long trough allows for the concomitant coloration of several stems, resulting in uniformly colored logs and, consequently, in a homogenous batch of veneer.

In a setup similar with the one described in Drawing 1, the coloration of entire stem occurs in 1 to 3 days, in which, as a result of the suction created by the still living crown, the dyeing solution replaces gradually the natural sap. In the process, the dye acts as a contrast substance that circulates only through the sap-conducting elements, as opposed to wood fibre. Since penetration of dye in wood fibres can occur only through lateral diffusion, at a much smaller rate, the color of non-conducting elements remains practically unaffected. As the deposition of the dyeing agent occurs continuously when there is a demand for transpiration, the contrast between various elements of wood anatomy increases with time or amount absorbed. With it, the natural texture of wood, that is specific for every tree species, is revealed. By using aqueous dye solutions of low concentration, S under the functionality of the foliage is maintained and the resulting impregnation is uniform along the stem, thus creating an appealing contrast between the anatomic S elements of the wood that are conducting the solution and those that are not conducting.

Conversely, the effect of using concentrated dye solutions is a sharp reduction of foliage S functionality, and a degrading coloration along the stem. If desired, this degrading can also be an object of aesthetic exploitation.

Other solvents than water, that may dissolve the dye, how.ever, will not move in the sap-conducting system of a tree.

When the veins of leaves start showing the same color as the dye in which the cross section has been immersed, the coloration can be considered terminated. From that point in time on, coloring may continue as long as the foliage remains functional. This finding may be used to obtain variations of color saturation. Therefore, the intensity of coloring of the stem can be tunned better through time manipulation, rather than through variation of solution concentration. For reasons of hue uniformity of large batches of veneer, at that time, the solution remaining in the trough has to be considered "spent" and has to be drained and replaced with a new solution. When the color is changed, the trough has to be rinsed at least twice.

After the coloration has been started, the trough has to be inspected hourly. If the level of the solution is low, new solution with similar concentration has to be added, so as to keep continuously the cross sections completely immersed.

At any time judged appropriate, the operator can interrupt the dyeing by removing the section from solution, achievable either by lifting of tree or by draining of trough.

Among the wide selection of commercially-available dyes, the most appropriate are the dyes recommended by the manufacturing firms for pulp fibre or for paper. However, dyes of other categories may also circulate in the sap-conducting system of the tree..

The dyeing agent has to be applied with no added salt or additives, in order to maintain the tree alive as long as possible. Here the procedure is at great variance with technologies applied for the dyeing of cotton in the textile industry, which use additives to achieve chemical fixation of dyes to fibre. Moreover, the dye can be either a "direct" or a "reactive" dye thus allowing for a practically unlimited range of colorations obtainable.

Use of low concentration of dye solutions, under allows for the minimization of the pollution risks, since only an insignificant amount of residue, consisting of dirt, will form at the bottom of the trough after several batches of trees. An operational advantage of the treatment is therefore derived from the use of low concentration solutions. In the tree, the foliage uses only the water for transpiration, while the molecules of the dyeing agent adhere to the walls of the conducting elements. However, because there is no differential absorption between the agent and the solvent, the solution decreases only as a volume and not as concentration. The advantage consists in the fact that the trough does not have to be emptied and washed after every batch of trees, unless the color is changed. Instead, refilling of the trough can occur for several batches, as long as the color is maintained, with the only residue possibly building up in the trough being some insoluble dirt brought there by the skidding process or built up by the residue of the dye itself.

It will be noted that with the present invention a simple arid inexpensive procedure has been discovered. It can be utilized directly in the forest, regardless of tree species, age and size of tree. Essentially, if the precise timing of application is observed, no limitations are imposed on this procedure. Fine tunning of the operation, however, may be necessary for some species and some dyes, in order to obtain a certain color saturation.

While the main aim of this invention was to discover a method whereby the natural texture of common timbers could be revealed, it is also apparent from the foregoing description that the present invention allows for the impregnation of wood with various other substances, so as to obtain colorations non-existent in the nature or impregnations with a protective role.

A complement to this technology achieves both an enhancement of the aesthetic effects, enlarging the potential uses of veneer, and a productivity increase of the slicing operation. It can be applied either to 31ready colord logs or to logs which are intended to remain in the natural color. The aim of this complement is the replacement of the classic The terms "direct" and "reactive" are used here with the meaning accepted in the dyeing industry.

slicing of a cylinder, the log, resulting in veneer sheets of varying widths, with the slicing of a block, or "slab," of reconstituted timber with a square or rectangular section, resulting in veneer shets of equal width. It consists of a series of operations to be accomplished in the factory, prior to slicing in veneer, such as: 1. Formatting the individual logs into prisms of standard dimensions.

2. Combining the formatted prisms according to various criteria g. alternating colors, species or patterns), Drawing 2.

3. Glueing the prisms under pressure to result in a "slab," with a square or rectangular cross section, and 4. Slicing the "slab" in veneer.

This complements to the main technology allows for the standardization of the S: "slabs" and, implicitly, results in standard sheets of veneer. In comparison to the classic o slicing of logs individually, this should be looked as a major gain. It has been approximated that this complement reduces the wastage of veneer due to irregular individual sheets by at least 30%. In the case of a large-scale furniture production facility, standardization can S* be pushed even further, for instance, for preparing "slabs" to result in veneer sheets for doors, tabletops, cabinets, etc., thus further reducing the veneer wastage.

It will be noted that implementation of this complement replaces the need of workers to assemble the individual veneer slices, before glueing on a substrate, a time-consuming phase, with the positioning of a whole sheet of veneer over the same substrate.

Apart of the increase in productivity of slicing and assemblage, the importance of this complement grows further when we consider that its adoption allows for the use of logs of small dimensions, not considered up till now apt for the veneer production.

Finally, the complement results in a completely new product: polychrome veneer, S which cannot be made by any other means.

By implementing this component, a large variety of aesthetic combinations can be obtained (polychrome veneer), a new resource can be used (thin logs), and the productivity of the slicing operation and assemblage increases considerably. Once revealed through a contrast substance, such as a dye, the texture of indigenous species appears to be just as diverse, pleasing and interesting as that of the exotic timbers. Therefore, an existing resource can be substantially appreciated in terms of value. It can be most useful in the furniture industry and allows for the increase of the value of common species, which, after 2) The term "slicing" is used here with the meaning accepted in the forest industry.

impregnation, can be cut in aesthetic-quality veneer. In addition, the advent of this procedure allows for creation of colorations inexistent in the nature, thus increasing its range of applicability, for instance, for children's furniture.

Apart of common, indigenous tree species to which this technology can be applied, it should be noted that it can be also successfully applied to bamboo species.

6. Environmental concerns Given the fact that some dyes leave small amounts of residue, a special tank with a simple manual agitator should be used for solution preparation. Only clear solutions will be transferred to the troughs. The residue, moved as a suspension at the time of either solution preparation or tank cleaning g. for a change of color), will subsequently be S dried and the remaining dust should be ultimately disposed to a licenced landfill.

e 0*0 7. Use of invention

**S

Apparition of this procedure is important because it allows for the conversion of timbers that are cheap and available into quality logs. Thus, aesthetic-quality logs can be S produced from an indigenous resource. Then, the main use of the logs is veneer manufacture through slicing (or peeling when the complements are not applied) from the straight portion of the lower stem.

An additional use includes wood panelling, appropriate for remodelling homes, hotels and restaurants, where this technology will enlarge the current choice of materials.

In their search for adding additional living space, many homeowners may desire to have a wider assortment, than that traditionally available in hardware stores.

Also, veneer prepared under this technology will be used for the manufacturing of doors, allowing for a greater chromatic variation..

An yet additional use is the wooden flooring, called also parquet. This use will result in a greater variety of timbers and bamboo used for parquet than is currently the case, when the main species employed for this use are various oaks. At the same time, it opens the possibility of creating more diversified patterns of polychrome parquets, from various combinations of timbers, in natural and/or modified colors.

Finally, diversified uses can be devised by artists and decorators.

However, the main use will likely be in the furniture industry, where demand for quality veneer is increasing while the availability of traditional sorts has decreased sharply.

The invention holds significant potential for the forest industries, where the raw material is available, for both internal use of derived products and/or for increasing the value-added of export of veneer or furniture.

8. Advantages of invention It will be noted that with the present invention a simple and inexpensive technology for timber aesthetization is provided. Such treated logs can be manipulated subsequently as typical exotic logs, for the handling of which well proven technologies exist. No changes are necessary in the subsequent technological phases of slicing or peeling in veneer, drying, packing or application over substrates. Technological parameters, such as speed, temperature or pressure, as well as additives, such as glues and lacquers, typically applied when exotic logs are processed, are to be maintained for the products obtained from dyed .logs.

It is also apparent from the foregoing description that the present invention opens up a new, potentially large, international market for the forest industry. Having both a large resource of raw material and a procedure to convert it, with a minimal expenditure, to a high value-added product, the preceding description represents a superior alternative to the current exports of only primarily manufactured wood industry products.

9. Claims: Inasmuch as various changes may be made in the selection of impregnants, variations of technologies and finite products, without departing from the scope of the present invention, the following claims are formulated: Independent: Claim 1. A procedure to introduce in the stem of tree of a dissolved contrast substance, based on suction generated within a short delay after felling the tree, when the foliage is still healthy and active and can continue to absorb diluted aqueous dye solutions for several days before wilting (art).

Dependent: Claim 2. Derived from previous claim is the fact that, in the embodiment described, the tree under treatment is able to eliminate from solution only the water and to depose the dyeing agent in its sap conducting tissues in an uniform, reproducible manner along the stem, thus creating a chromatic contrast with the non-conducting elements which remain in natural color (process).

Claims (2)

1. 8. Advantages of invention It will be noted that with the present invention a simple and inexpensive technology for timber aesthetization is provided. Such treated logs can be manipulated subsequently as typical exotic logs, for the handling of which well proven technologies exist. No changes are necessary in the subsequent technological phases of slicing or peeling in veneer, drying, packing or application over substrates. Technological parameters, such as speed, temperature or pressure, as well as additives, such as glues and lacquers, typically applied when exotic logs are processed, are to be maintained for the products obtained from dyed .logs. It is also apparent from the foregoing description that the present invention opens up a new, potentially large, international market for the forest industry. Having both a large resource of raw material and a procedure to convert it, with a minimal expenditure, to a high value-added product, the preceding description represents a superior alternative to the current exports of only primarily manufactured wood industry products.
2. 9. Claims: Inasmuch as various changes may be made in the selection of impregnants, variations of technologies and finite products, without departing from the scope of the present invention, the following claims are formulated: Independent: Claim 1. A procedure to introduce in the stem of tree of a dissolved contrast substance, based on suction generated within a short delay after felling the tree, when the foliage is still healthy and active and can continue to absorb diluted aqueous dye solutions for several days before wilting (art). Dependent: Claim 2. Derived from previous claim is the fact that, in the embodiment described, the tree under treatment is able to eliminate from solution only the water and to depose the dyeing agent in its sap conducting tissues in an uniform, reproducible manner along the stem, thus creating a chromatic contrast with the non-conducting elements which remain in natural color (process). Claim 3. The end result of the procedure is colored logs of timber that can be sliced in veneer, or other wood products, and can be processed further with the same machinery and substances as commonly existing in a typical furniture factory (process). Claim 4. The technology of log coloring and slab preparation, explained above, will allow for the use of timbers otherwise considered unsuitable for veneer manufacturing (process), will significantly increase the productivity of mechanical implements involved (process) and will increase the range of feasible combination with aesthetic merit (art). Claim 5. Critical for the success of this procedure is the usage of diluted dye solutions, allowing for a long functioning of foliage after felling and the ensuing internal filtration that separates water from the dyeing agent and renders the contrast between the sap conducting (vessels) and non-conducting (fibre) elements of wood structure, thus resulting in a novel, pleasing wood texture. Except for the aqueous solution of dye, no S other additive is necessary for this procedure to result in a uniform and permanent coloration, to the extent provided by the particular chemical substances used for coloring (composition of matter). go, Inventor information Inventor Name: Chris Papadopol Address: 89 Pine Street, Unit 1205, Sault Ste. Marie, Ontario CANADA, P6A 6M6. November 15, 2001.