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(11) | EP 2 062 707 A2 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Method for treating wooden surfaces, use of said method and wooden surface obtained by the method |
| (57) The invention relates to a method for treating a wooden surface, said method including
at least the following steps: - the wooden surface is set into contact with the smooth contact surface (3) of a rock-material piece (30), - the wooden surface and the contact surface (3) of the rock-material piece (30) are moved in relation to each other, and at the same time a certain homogeneous compression pressure (P) is created therebetween, said pressure being such that the wooden surface is compressed, but any wooden material, such as wood fibers, is not, however, essentially removed from the wooden surface, - after said wooden surface is compressed, it can be treated, at the moment of treatment, by a liquid or solid coating, at least once. |
[0001] The invention relates to a method according to the preamble of claim 1 for treating wooden surfaces.
[0003] In addition, the invention relates to a wooden surface, particularly the surface of a wooden door that is treated according to the method.
[0004] The invention also relates to a door with a wooden surface that is treated according to the method.
[0005] The starting point of the method was a purpose to eliminate two drawbacks of the prior art. The first drawback is connected to wooden doors that may be susceptible to moisture. The absorption of moisture in a wooden surface already treated with an anti-absorption agent mainly seems to be due to the fact that the surface wood fibers start protruding upwardly, in case the wooden surface is first treated by a regular surface treatment method including several grinding steps, and thereafter by a liquid coating, constituting a film or a layer that prevents the absorption of water. When the wood fibers start protruding, the coating surface is broken, and moisture gains access to permeate into the wood material.
[0006] The drawback is particularly serious in wooden doors, at the border surface of two different wood materials. For example, in currently used doors, in the door leaves and frame or edge boards there are used different materials, which means that at the border surfaces of these materials, moisture has easy access to permeate underneath the coating, for instance under an edge strip, and further into the wooden structures. Currently the access of moisture into the wood material of a wooden door is attempted to be prevented by coating the edge board or frame susceptible to moisture by a solid coating, such as laminated coating, or by a homogeneous film, such as paper coating, which is impregnated with resin. Irrespective of these measures, in the long run doors are susceptible to moisture damages that are caused by the access of moisture into the strip covering the edge (generally a resin-impregnated paper film or paper laminate) through the edges to the frame or edge board, particularly to the wooden structures at the lower edge, which results in that the strip becomes loose, whereafter the wooden material at the lower door edge is distorted. Wooden surfaces have also been treated by an anti-absorption agent, so that the surface is first moistened, and after drying, the protruding wood fibers have been cut by grinding. Thereafter the surface has been treated by an agent preventing the absorption of moisture. However, the results of this kind of wooden surface treatment are relatively unreliable, and after the treatment, the wood fibers tend to protrude again. This drawback can be avoided by impregnating the edge board of the door, but this results, among others, in that the door manufacturing expenses are remarkably increased.
[0007] As a starting point for the present invention, another drawback is connected to frame doors, where the door leaf is formed of one or several different wooden materials, or where the door leaf is made of porous fiberboard. Here the edges of the wooden panel may remain coarse, and it is necessary to remove the coarseness by repeated grinding treatments.
[0008] With respect to the above described drawbacks, the main objective of the applicant was to develop a fast and economical treatment method particularly for wooden surfaces, whereby the properties of the wooden surface can be improved, so that its further coating with a liquid surface treatment agent or with a solid coating is durable. A particular objective was to achieve a treatment method for wooden surfaces, where the wooden surface obtains such properties that after the treatment, it can be coated by a permanent, liquid agent that protects the wooden surface against moisture.
[0009] By means of the method according to the invention for treating wooden surfaces, and by the use of said method for treating wooden surfaces, the drawbacks of the prior art can be eliminated.
[0010] More precisely, the invention relates to a method according to claim 1 for treating wooden surfaces. The method includes at least the following steps:
- a wooden surface is set into contact with the surface of a rock-material piece with a smooth surface,
- both the wooden surface and the surface of the rock-material piece are moved in relation to each other, while a certain compression pressure P is created therebetween, which compression pressure is such that the wooden surface is compressed, but any wooden material, such as wood fibers, is not, however, essentially removed from the wooden surface,
- after said wooden surface is compressed, it is treated by a liquid or solid coating, for at least once.
[0011] Advantageously the wood material is reduced by no more than 5 %, preferably no more than 1 % of the material that is removed in a regular grinding treatment.
[0012] Here an object made of rock material means an object made of solid rock, such as volcanic stone, for instance granite; rock of sedimentary origin, such as limestone; rock of metamorphic origin, such as gneiss. In addition, this term refers to objects that are made of the crushed stone from one or several solid rocks and/or rock-forming minerals and/or a material with a hardness corresponding to solid rock or rock-forming mineral, added with an adhesive medium.
[0013] The term wooden surface refers to a surface having wood fibers. The surface is the surface of for instance wood panel, solid wood or laminated wood. The wood panel can be a glued timber board made of wood elements, a wood fiber board, a glued veneer plate, plywood or chipboard. The wood fiber board can be for example a porous, medium-hard or hard fiberboard. The medium-hard fiberboard is also called MDF plate, and the hard fiberboard is called HDF plate.
[0014] In this application, the term coating refers to surface treatment by surface treatment agents, such as liquid paints or varnishes, but also by wood protective liquids that form a moisture-protective layer or film on the wooden surface. In addition, the term coating refers to coating the wooden surface by a solid coating, such as hot melt adhesive, or a film coating to be glued on, or a self-adhesive film coating. Film coating often comprises a paper foundation, which is impregnated by a thermoplastic adhesive medium. Examples of such thermoplastic-impregnated paper foundation coatings are papers impregnated by thermosetting melamine resins, phenol formaldehyde resins and urea resins, which are laminated in several superimposed layers and placed on the wooden surface. A film coating can also be formed of papers impregnated by thermoplastic or by resins, such as melamine or PVC resins, which papers are then glued by thermoplastic on the wooden surface. Among film coatings of the latter type, there are also veneer to be glued on the wooden surface and thermoplastic film, which are also regarded to be included in coatings. In the present application, a coating is advantageously a liquid surface treatment agent that is spread, sprayed or rolled on the wooden surface.
[0015] An advantageous surface treatment agent is a low-viscosity acrylate primer or an acrylate top paint.
[0016] By means of the method according to the invention, there is achieved the advantage that the protrusion of wood fibers can thereby be prevented owing to the effect of the liquid surface treatment agent, and by compressing the wooden surface prior to treating it by a liquid or solid coating.
[0017] The compressing method of a fiberboard surface or a wooden surface according to the invention is based on that the surface of a sufficiently smooth rock-material piece is pressed by a suitable, relatively low and uniform compression force P against the wooden surface, and at the same time said rock-material piece and the surface of the fiberboard or wood are moved with respect to each other, so that essentially no material is removed from the wooden surface that is in contact with the rock-material piece during the treatment according to the method. Accordingly, the method is based on the fact that the surface is mechanically sealed by compressing the wood fibers onto the surface. The purpose is to keep the surface pressure low in the contact area between the wooden surface and the rock-material piece, and therefore the contact surfaces, i.e. the surface to be compressed and the compressing surface of the rock-material piece, are maintained in parallel during the compressing operation. Moreover, the surface pressure in the contact area between the wooden surface and the stone material surface should be maintained as smooth, i.e. as homogeneous as possible, in order to avoid the rising of the surface pressure in the contact area even momentarily so high that wooden material is removed from the wooden surface. In order to maintain the surface pressure in the contact area between the wooden surface and the rock-material piece sufficiently low and homogeneous, the motion between the wooden surface and the stone material surface is advantageously linear back and forth motion. After compression, the compressed wooden surface is not subjected to any material-removing or wood-fiber cutting surface treatment methods, such as grinding, but immediately after surface compression, the surface is treated by a liquid coating, preferably a liquid surface treatment agent, such as an agent creating a moisture stop. The purpose of the liquid surface treatment agent is to ensure that the wood fibers pressed on the surface remain permanently fastened by gluing them to the wooden foundation. Advantageously the rock-material piece is made of stone powder, such as soapstone powder or calcium silicate, and adhesive medium, which improves the adhesion of the wood fibers to the wooden foundation. When the wooden surface is compressed by means of this kind of rock-material piece, the adhesive medium, that during the compressing process gets loose from the stone material, seals the wood surface by gluing. By using this kind of rock-material piece, there also is achieved the additional advantage that the wood fibers remain better on the wood surface and do not protrude and damage the moisture stop added on the surface. Advantageously the added moisture block is an acrylate paint or varnish.
[0018] A wooden surface treated by a method according to the invention is compressed, and at the same time its moisture content and liquid permeability are decreased.
[0019] In a preferred embodiment of the invention, the wooden surface to be treated is a plate-like wooden surface, which after compression is treated by a liquid surface treatment agent. In the surface treatment, the plate-like wooden surface is spread/sprayed/impregnated by a moisture barrier and/or an anti-microbial agent and/or an agent that preserves the physical features of the wooden surface and/or a pigment.
[0020] In a preferred embodiment, the method is advantageously used for compressing the outer surface of the edge board of a door. Thus for example in a panel door or a form pressed door built for humid environments, the outer surface of a frame or edge board is compressed, so that it can be treated by an agent permanently preventing the absorption of moisture.
[0021] Yet in a preferred embodiment of the invention, the method according to the invention is used for compressing the panel edges of a frame door after the manufacturing of the panel elements, such as milling. Because the wood fibers of the wooden surface are not cut in the present method, the treatment with a liquid surface treatment agent does not make the wood fibers protrude, and one single treatment suffices for finishing the panel edges.
[0022] In another preferred embodiment of the invention, the desired elements of a wooden door are treated by the method according to the invention prior to compiling the door. Thus for instance the panel elements of a door to be compiled of elements can be compressed separately, and the outer edge of the frame of the frame door can be compressed separately, whereafter the panel elements and the frame can be assembled.
[0023] As regards other additional advantages that are achieved by the invention, let us point out that a wooden surface compressed by the method according to the invention absorbs less liquid surface treatment agent than an uncompressed surface. A compressed surface is often smoother than wooden surfaces achieved by other methods, especially when the rock-material piece used in the compressing is an alloyed rock-material piece, of which stone material that further smoothes the wooden surface is loosened during the compression. This kind of compressed wooden surface is easier to be dyed homogeneously than for instance a ground surface. In some cases, the surface to be compressed can also be polished by means of the method according to the invention.
[0024] The invention and the advantages achieved thereby are described in more detail by way of examples and with reference to the appended drawings.
[0025] Figures 1A, 1B and 1C, 1D and 1E illustrate various rock-material pieces to be used in connection with the invention.
[0026] Figure 2A is a schematical side-view illustration of the compressing of a door frame according to the method of the invention.
[0027] Figure 2B illustrates the cross-section the door shown in Figure 2A, viewed in the direction IIB.
[0030] Figure 3 is a schematical illustration, seen in an inclined top view, of the compressing of the edge of the wooden panel of a panel door by means of the method according to the invention.
[0031] Figure 4 is a schematical side-view illustration of the method according to the invention as applied in the treatment of the surface of a parquet block.
[0032] Figure 5 is a schematical illustration of the basic principle of the method according to the invention.
[0034] Figures 1A-1E show examples of various rock-material pieces. In the rock-material pieces 30; 32 shown as perspective illustrations in Figures 1A and 1B, the contact surface 3 is smooth and especially suited for compressing planar wooden surfaces, cf. for instance the compressing of the surface of the straight rear edge 22; 22" of a flush door illustrated in Figure 2C. The rock-material pieces 30 illustrated in Figures 1A and 1B can be solid rock objects 32, in which a smooth contact surface 3 is made by splitting.
[0035] The contact surface 3 of the alloyed rock-material pieces 30; 31 shown as perspective illustrations in Figures 1C and 1D is stepped and thus suitable for example for compressing the outer surface of a double rebate edge board of a door, or the outer surface of a single recessed edge board of a door (cf. Figures 2B-2D). The alloyed rock-material piece 30; 31 illustrated in Figure 1E is formed cylindrical, so that its contact surface 3 composed of a cylindrical shell is suitable for example to the compressing of the wearing surface 5a of a parquet block 5 (cf. Figure 4).
[0036] The rock-material pieces 30 used in the invention can be formed of one solid rock material piece, such as granite, or they can be alloyed rock-material pieces including one or several types of stone and/or rock-forming mineral, for instance soapstone and granite. Also crushed artificial materials with a hardness corresponding to that of rock-forming minerals are suitable for manufacturing the rock-material pieces. Among these, let us point out several building industry materials, such as objects made of various calcium salts, for instance calcium silicate. The shape of the contact surface 3 of the rock-material pieces 30, i.e. the shape of the surface compressing the wooden surface, corresponds to the shape of the wooden surface to be compressed, against which the contact surface 3 is pressed at a certain uniform force P.
[0037] Suitable types of stone to be used in the invention are volcanic stone species, such as granite, rocks of sedimentary origin, such as limestone, or rocks of metamorphic origin, such as gneiss, as well as different rock-forming minerals, such as feldspar, that occur as such or generally bound in solid rock material. For instance the rock-material pieces illustrated in Figures 1A and 1B, where the contact surface 3 is smooth, can be formed of a solid rock boulder by splitting. In most cases, the rock-material pieces used in the invention are alloyed rock-material pieces 30; 31 made of stone or mineral powder (crushed stone) or a material with a corresponding hardness plus an adhesive medium, because with these, it is easiest to obtain the desired shape for the compressing surface 3 for compressing the wooden surface, and in addition, when necessary, these rock-material pieces 3 can be utilized for bringing onto the wooden surface stone powder that fills the grooves in the wooden surface. The hardness of the stone material used in the invention is at least 1 On Moh's scale of hardness (for example talcum powder, several cement-based building industry materials), preferably, however, at least 2-3 (for instance soapstone, calcite mineral).
[0038] The adhesive medium is chosen according to the type or types of crushed stone used in the alloyed rock-material pieces, as well as according to the wooden surface to be compressed. The purpose of the adhesive medium is to bind the crushed stone particles together sufficiently firmly when manufacturing alloyed rock-material pieces. In addition, it is important to take into account that in the manufacturing of alloyed rock-material pieces, there is often used crushed stone or powder made of two or several different types of stone or rock-forming minerals, for example for adjusting the surface hardness of the alloyed rock-material piece, in which case the adhesive medium must be suited for mutually binding the particles of several types of stone or rock-forming minerals. The adhesive medium may also be used for gluing wood fibers onto the wooden surface to be compressed, in which case the adhesive medium should also have adhesive features suitable for wood, i.e. properties that increase the adhesion of wood fibers onto wood. Because the properties of stone and wood are remarkably different, among others as regards their polarity, there is generally used a separate adhesive added in the stone material, suitable for the wooden surface, in order to increase the adhesion of the wood fibers onto the wooden surface. If the adhesive or adhesive medium should during the compressing process get into contact with the wooden surface to be compressed, in order to bind wood fibers to said wooden surface, the rock-material piece itself must be made of a relatively soft stone, such as soapstone. Suitable agents that increase the adhesion of wood fibers onto a wooden foundation are thermoplastic adhesives used for gluing wood, including contact adhesives, such as chloroprene-based contact adhesives, adhesives based on polyvinyl acetate (PVAc), hot melt adhesives, such as hot melt adhesives based on ethyl-vinyl acetate co-polymer (EVA), ethylene-acrylate co-polymer (EEA), polyethylene (PE) and polypropylene (PP), and mineral adhesives known from the manufacture of chipboard. Polyvinyl acetate based adhesives have turned out to be advantageous, especially in compressing the edge surfaces 22 of a door.
[0039] The rock material of the alloyed rock-material piece 30 is chosen according to the properties of the surface to be compressed. It is often desired that during the compressing operation, from the surface of the rock-material piece, there is released stone powder for filling the holes and grooves created on the wooden surface. In that case the material chosen for the rock-material piece is a soft, porous stone or rock-forming mineral, such as soapstone. The surface of for instance porous wood fiber boards and chipboard, as well as to some extent the surface of semi-hard wood fiber boards, often remains uneven after manufacturing. By using a rock-material piece made of a soft type of stone/rock-forming mineral for the surface compressing of a wood-based fiberboard, such as a soapstone object, the surface irregularities are filled. Consequently, there is obtained a smooth foundation for coating with a liquid surface treatment agent that takes place after compressing.
[0040] The compressing contact surface 3 of the smooth-surfaced rock-material piece is so smooth that said contact surface does not essentially cut the wood fibers in the wooden surface, when the contact surface 3 is set into contact with the wooden surface, and the contact surface 3 and the wooden surface are pressed together in a certain contact area by a uniform compression force P, and at the same time said surfaces are moved with respect to each other. In each case, the highest possible coarseness of the contact surface 3 of the rock-material piece in question depends on the hardness of the wooden material to be compressed, and on the applied compression pressure P. The hardness of the wooden material in turn is affected, among others, by the species of wood and the manufacturing method of the surface; for instance the surfaces of massive wood, chipboard, veneer, fiberboard and adhesive wood panel all have different surface hardnesses, depending on the way the wood material has been worked.
[0041] Figures 2A and 2B illustrate an embodiment of a preferred embodiment of the invention. There a form pressed door 2; 2a is conveyed along a conveyor track 7 from right to left. In the drawing, the form pressed door 2; 2a and its treatment by the method according to the invention are illustrated in a simplified manner. The door 2; 2a can be treated according to the method of the invention prior to fastening it to the door frame and fixing the fittings. Figure 2B represents the cross-section of the door 2; 2a according to Figure 2A seen in the direction IIB of Figure 2A. Here the term form pressed door 2; 2a refers to an (internal) door, with a core 27 that has a cellular structure, and the cellular core is surrounded by an edge board 20; 201. On both sides of the edge board 201 and the cellular core 27, there are pressed door leaves (wood fiber boards) 25; 25', 25" in a desired shape. A currently popular door type is compiled of edge board 20; 201 made of MDF plate or glued timber plate, on top of which there is on both sides placed a hardboard by cold or hot pressing in order to serve as the door leaf 25.
[0042] The door to be treated could also be a flush door 2; 2b, the cross-section of which is schematically illustrated in Figure 2C, or a frame door 2; 2c, the cross-section of which is schematically illustrated in Figure 2D. The cross-sections in Figures 2C and 2D are illustrated as viewed from the same direction as the cross-section of the form pressed door in Figure 2B, i.e. as viewed from the top end of the door 2.
[0043] The term frame door 2; 2c here refers to a door where the supporting structure is a wooden, rigid frame 20; 203. The material of the frame board 203 serving as the edge board and frame is made of solid wood, glue board, laminated wood or wood fiber board, for instance medium-hard fiberboard (so-called MDF plate). Inside the frame board 20; 203 serving as the frame, there is provided as a "filling" 27 a door leaf (panel element) 25, which is a wood panel or a glass plate. The panel element 25 constituting the wood panel 25 is made of solid wood, plywood, panel board, hard or medium-hard fiberboard or currently also of possible combinations of these, glued together. Figure 2D illustrates a schematical cross-section of a frame door 2; 2c.
[0044] The term flush door 2; 2b here refers to a door where the supporting body is formed of a cellular core 27 and filling, as well as of an edge board 20; 202 surrounding the filling. On both sides of the edge board 20; 202 and the core 27, as well as the filling connected thereto, there are glued wood panels 25; 25', 25". The material of the edge board 20; 202 and the wood panels 25 is often the same as that of the frame door 2; 2c.
[0045] Thus the edge board 20 can be a frame board 203 of a frame door 2c, an edge board 202 surrounding the body of a flush door 2b, or an edge board 201 provided in between the form pressed wood panels 25; 25', 25" of a form pressed door and encircling the outer edges of the panels. The material of the edge board 20 is solid wood, glued wood or currently often wood fiber board, particularly MDF fiberboard. The edge board can also be manufactured of a combination of various different materials, for instance of glued or solid wood, which is covered by a wood fiber board.
[0046] The wood panels 25 of both the frame door 2c and the flush door 2b can be further coated by a suitable surface material, such as veneer, panel, plywood board or fiberboard.
[0047] In the form pressed door 2; 2a illustrated in Figures 2A and 2B, the edge board 20; 201 is made of semi-hard wood fiber board (MDF plate), which surrounds the cellular core 27 of the door 2; 2a. On top and underneath the edge board 20; 201, there are placed door leaves 25; 25'. 25", which are wood fiber boards (HDF plates) that are hot or cold pressed in shape on top and underneath the cellular core 27. Each edge side of the edge board 20; 201 is rectangular in its cross-sectional profile. Panels 25a are shaped in the door leaves 25; 25', 25" of the press door during a compression process.
[0048] Beside a conveyor track 7, on both sides of the track, there is placed a number of alloyed rock-material pieces 30, made of crushed soapstone or so-called siporex, supported by their support arms 61, which in turn are supported by the longitudinal guide 6 of the conveyor track 7. The form pressed door 2; 2a illustrated in the drawing has a similar edge rebate 20a; 20a" and 20; 20a' both on the side of the longitudinal surface 22; 22" of the edge board 20; 201 facing the viewer, and on the longitudinal side 22; 22' of the edge board 20 directed away from the viewer. Therefore the contact surfaces 3 of the rock-material pieces 30 getting into contact with the outer surface 22 of the edge board 20; 201 must be shaped so that they conform to the edge rebates 20a; 20a', 20a' made in the outer surface 22 of the edge board; here the contact surface 3 getting into contact with the outer surface 22 of the door edge board 20 of the rock-material pieces 30 could be shaped for example to be similar in cross-sectional profile as the one illustrated in Figure 1D.
[0049] In case the wooden surface 22 of the outer edge of the edge board 20 of the flush and frame doors according to Figures 2C and 2D should be compressed, the shape of the contact surface 3 of the rock-material piece 30 should be selected to conform to the surface shape of their outer edge 22. In the flush door 2; 2b illustrated in Figure 2C, the first longitudinal outer edge 22; 22' of the edge board 20; 202 is provided with a rebate 20a, and consequently a rock-material piece with a contact surface 3 similar to the one illustrated in Figure 1D can be used for compressing this edge. On the other hand, the second outer surface 22; 22" of the edge board 20 of the flush door 2; 2b is straight, and thus for compressing said edge, there could be used rock-material pieces 30 similar to those illustrated for example in Figures 1A and 1B, where the contact surface 3 is smooth. In the drawing of Figure 2D, the first longitudinal outer surface 22; 22' of the frame 20; 203 of the frame door 2; 2c has a rebate 20a, and thus for compressing said surface, there can again be used a rock-material piece with a similar contact surface 3 as was illustrated in Figure 1D. The second longitudinal outer surface 22; 22' (the rear edge of door 2c) of the frame board 20 is shaped in its surface profile, so that the contact surface used for compressing it is that of an alloyed rock-material piece with a corresponding shape.
[0050] In Figure 2A, the contact surfaces 3 of the rock-material pieces 30, turned in the direction of the form pressed door 2; 2a, get into contact with the longitudinal outer surfaces 22; 22' and 22; 22" of the door edge board 20, when the door 2 is conveyed on the conveyor track 7 horizontally from right to left. The motion between the outer surface 22 of the edge board 20 and the contact surface of the rock-material piece 30 within their contact area is a rectilinear motion. When so desired, the linear motion can also be arranged to be reciprocating by moving the support arms 61 of the rock-material pieces 30 back and forth along the guides 6 at the same time as the form pressed door is conveyed along the conveyor track.
[0051] The compression pressure P (surface pressure) between the outer surface 22 of the edge board 20 and the contact surface of the rock-material pieces 30 is now arranged, in their contact area, to be such that the contact surface 3 of the rock-material piece 30 that is pressed against the outer surface 22 of the edge board 20 compresses the outer surface 22 of the edge board by pushing the wood fibers to stick fast to the wooden surface 22, without, however, essentially cutting the wood fibers. In the contact area, the surface pressure directed to the wooden surface 22 should be as homogeneous as possible, wherefore the contact surface 3 of the stone material must be smooth, in order to prevent wooden material from being released from the wooden surface 22 while the surface is being closed. By means of the rock-material pieces 30 placed in succession in the longitudinal direction of the conveyor track 7, beside the conveyor track, the wood fibers located on the longitudinal outer surfaces 22; 22' and 22; 22" of the edge board 20 are pressed in order to stick fast to the outer surface of the wood by such a force that when said wooden surface is later moistened by an anti-absorption liquid or by another liquid surface treatment agent, the wood fibers do not protrude again. Thereafter the outer surfaces (outer edges) 22 of the edge board 20 that run in the direction of the width of the board are compressed in a similar arrangement as in the drawing.
[0052] When the desired outer surfaces 22 of the edge board 20 are compressed, they can be treated by a suitable liquid surface treatment agent. In case the door 2; 2a should be used for example in humid facilities, the outer edges 22 of the edge board 20 were treated by a suitable anti-absorption agent meant for wood-based surfaces, particularly for instance its lower edge by a water-thinned acrylic paint or varnish, without, however, being solely restricted to these; the treating of wooden surfaces by surface treatment agents for preventing the absorption of moisture is known as such in the prior art, and several other surface treatment agents suited for interior use that prevent moisture from being absorbed in wood can also be applied here. When the moisture block has dried, the outer edges 22 can be treated further in a regular way by glaze painting, varnishing and/or pigment painting with a suitable surface treatment agent. During the further treatment of the outer edges, the above described compressing of the wooden surfaces can be repeated for instance after priming.
[0053] In case there regular surface treatment methods based on grinding were applied for the outer surfaces 22 (outer edges) of the edge board 20 of the form pressed door 2; 2a, the treatment by a liquid moisture block would make the wood fibers protrude, which would result in that the film or surface layer formed by the moisture block for obstructing the penetration of aqueous steam would be broken, and its operation in the desired way would be prevented.
[0054] Figure 3 represents another wood compressing method according to the invention. The drawing shows in a schematical illustration part of one panel 25a of a frame door panel element 25, which can be made for instance of porous fiberboard or solid-wood panel. In some door models, the panel bottom 25a1 and the panel edges 25a2 are also made of different materials and in different manufacturing steps. For example the panel bottom 25a1 can be made of pressed board, in which the panel shape is cold or hot pressed. The panel edge 25a2 can be for example pressed board or solid wood milled in shape, on top of which there is placed a pressed board milled in shape. Depending on the material and manufacturing method (for instance milling) of the bottom 25a1 and edges 25a2 of the panel 25a, for instance in the edges 25a2 of the panel 25a there may remain coarse spots that need to be smoothed prior to treatment with a painting, glazing or varnishing agent. In Figure 3, the edge 25a2 surrounding the bottom 25a1 of the panel 25a is already connected to the bottom 25a1 of the panel 25a, and the treatment of the edge is only carried out in this step. It is also possible to perform the treatment of the edge 25a2 or its elements before the edge is connected to the panel bottom 25a1. In case the frame door is manufactured of separately worked elements which are connected at the assembly stage, the panels of the panel element 25 and the outer edges of the edge board 20 can be compressed separately. Thereafter the panel element and edge board of the frame door, manufactured according to the method, are interconnected.
[0055] By moving the contact surface of the rock-material piece 30; 31 back and forth along the panel edges 25a2 at the same time as the edge and the rock-material piece are pressed together at a relatively low but still uniform compression pressure, the edges are compressed without cutting the wood fibers. In shape, the contact surface corresponds to that of the edge 25a2 of the wooden panel 25a to be compressed. Thereafter said wooden panel edge can be immediately further treated by surface treatment agents, without laborious grinding steps.
[0056] In Figure 4, the method according to the invention is applied in the wearing surface of a parquet block 5 for a boarded parquet floor prior to varnishing and grinding the wearing surface. The parquet block 5 is pushed from right to left with respect to a cylindrical, alloyed rock-material piece 30; 31 that rotates counterclockwise in relation to the proceeding direction of the parquet block 5. The contact surface 3 of the cylindrical rock-material piece compresses and possibly polishes the wearing surface 5a of the parquet block, whereafter the wearing surface 5a can be subjected to regular surface treatments, such as repeated varnishing and grinding steps. When the method is used for compressing the wearing surface 5a of a wooden parquet, the rock-material piece used for compressing is preferably relatively soft, so that the irregularities possibly found in the parquet wearing surface are filled with stone powder. Thus there is obtained a smooth wearing surface for the parquet block 5, which again facilitates its further processing, such as varnishing and grinding.
[0057] Figure 5 represents yet another schematical illustration of the wooden surface compression method according to the invention. Now the method includes the selection of a rock-material piece, made of crushed stone and adhesive medium, suitable for the wooden surface to be compressed, and the compression of the wooden surface without cutting wood fibers, by bringing the wooden surface into contact with the contact surface of the rock-material piece. The wooden surface and the rock-material piece are brought into mutual contact while the surface pressure applied on the wood surface is P, so that there occurs an adhesion of the wood fibers to the wooden foundation. The surface pressure is homogeneous throughout the whole contact area. The contact surface of the rock-material piece and the wood surface are during the treatment moved with respect to each other, preferably by a mutual linear motion. After this compression step, the surface is treated further by coating. At the moment of treatment, the coating can be carried out by a liquid surface treatment agent, such as a moisture block, an anti-mildew agent, paint, adhesion primer or varnish. At the moment of treatment, the coating can also be solid, whereafter it can be a molten surface treatment agent, such as a hot melt adhesive. The coating can also be a solid coating, such as an edge strip, both at the moment of coating and afterwards.
Example 6
Service test
[0058] A form pressed door, where the door leaves were HDF plates compressed in shape, and where in between the door leaves pressed in shape, there was provided a core with a cellular structure and an edge board made of MDF plate, was treated in the following way: the door leaves were primed, the edge board was first treated by compressing the untreated surface according to the invention by a rock-material piece, so that during the treatment, the MDF plate surface was compressed, and the liquids absorption capacity of the surface was weakened. During compression, any essential amounts of material were not removed from the board surface, which means that the quantity of removed wooden material was 0.1 -1% in comparison with a normal grinding treatment by material-removing grinding methods, such as treatment with sandpaper. The compressed door edge surfaces were treated by first applying a low-viscosity (density 1.3 kg, dry matter content 35 % by volume) water-thinned acrylate primer, which also was an adhesion primer meant for wooden surfaces. The primer was allowed to dry. After the primer, the edges were treated by applying a likewise low-viscosity (density 1.0 - 1.25 kg/l, dry matter content 40 % by volume) water-thinned acrylate top paint. When the top paint was dry, an anti-moisture film was glued on the surface of the edges.
[0059] The lower parts of the doors treated this way were irrigated by the VTT (Technical Research Centre of Finland) method M/250/08 for 10 minute periods, and in between the irrigation periods, there was always a 50 minute drying period. After 5 irrigation periods, the swelling in the lower parts of the doors was no more than 0.03 - 0.11 mm, while the swelling maximum for humid space doors is 0.25 mm after 5 irrigation periods. On the basis of said test, the edges of the doors treated according to the invention were compressed to the extent that the wood fibers did not protrude owing to the moisture.
[0060] Only a few preferred embodiments are described in the above specification, but for a man skilled in the art, it is obvious that the invention can be also be realized in many other ways within the scope of the inventive idea set forth in the claims.
[0061] Consequently, the method according to the invention can be generally used in the surface treatment of wood-based products both in the building and carpenter industry.
[0062] In the above specification, in connection with Figure 2A, there was described the compression method of the outer edges of the edge board 20 of a form-pressed door 2; 2a after the door leaves 25 of the form-pressed door 2a were compressed on two sides of the edge board 20 and core 27, i.e. the compression of the outer surface of the edge board 20 was the last step in the door manufacture, prior to the coating of the door 2, its fastening to the door frame and fixing the fittings. However, the compression of the outer surface 22 of the edge board 20 can be carried out prior to compressing the door leaves 25 on top and underneath the edge board 20 and the core 27.
[0063] In the embodiment illustrated in Figure 2, the outer surface 22 of the frame 20 is after compression coated with a surface treatment agent. The compression method according to the invention improves the fastness of the wood fibers in the wooden foundation, especially in case the rock-material piece 30 is an alloyed rock-material piece that contains an adhesive primer (adhesive material) improving the adhesion of the wood fibers to the wooden foundation. Now the method according to the invention can also be used for generally improving the fastness of a regular edge strip in building and carpenter products. Particularly in wooden doors or wooden doors provided with windows, the coatings employed for coating the edge 22 (in strips) have generally been various wooden strips, plastic strips - including plastic strips, laminated plastic-paper coatings and glued plastic impregnated paper coatings - as well as metal strips. By compressing the surface 22 of the door edge board 20 prior to its coating by a strip, the fastness of the strip is improved in humid conditions.
[0064] A wooden surface can also be treated by several compression steps, so that in between the compression steps, there is generally carried out a treatment with a surface treatment agent, such as priming with varnish or paint. Now in the first compression step, the wooden foundation can be compressed by using a rock-material piece with a coarser surface, and after the priming treatment, the wooden foundation can be compressed by a rock-material piece with a smoother surface.
[0065] In the above examples, we have described the treatment of a wooden surface by a method according to the invention, where a rock-material piece is moved back and forth along a wooden surface. The rock-material piece can also be moved for instance along a rotary trajectory on the surface of the object under treatment, in case the compression pressure between the rock-material piece and the wooden surface in their contact area remains homogeneous, and does not rise too high for example at the edges of the rock-material piece.
1. A method for treating wooden surfaces, said method including at least the following
steps:
- the wooden surface is set into contact with the contact surface (3) of a rock-material piece (30),
- the wooden surface and the contact surface (3) of the rock-material piece (30) are moved in relation to each other, and simultaneously there is created a certain homogeneous compression pressure (P) therebetween, throughout the whole contact area, said compression pressure being such that the treated wooden surface is compressed, but any wooden material, such as wood fibers, is not, however, essentially removed from the wooden surface,
- after the wooden surface is compressed, it is treated, at the moment of treatment, by a liquid or solid coating, at least once.
2. A method according to claim 1, characterized in that the method includes at least the following steps:
- the wooden surface of a wooden door (2) or the wooden surface of an element of a wooden door (2) compiled of elements is set into contact with the contact surface (3) of a rock-material piece (30), the shape of said contact surface corresponding to the shape of the wooden surface,
- the wooden surface of wooden door (2) or the wooden surface of an element of a wooden door (2) compiled of elements, and the contact surface (3) of the rock-material piece (30) are moved with respect to each other, and simultaneously there is created a certain homogeneous compression pressure (P) therebetween, throughout the whole contact area, said compression pressure being such that the treated wooden surface is compressed, but any wooden material, such as wood fibers, is not, however, essentially removed from the wooden surface,
- after said wooden surface is compressed, it can be treated, at the moment of treatment, by a liquid or solid coating, at least once.
3. A method according to claim 1 or 2, characterized in that from the wooden surface, there is removed no more than 5 %, preferably no more than
1 %, of the quantity of material that is removed in a regular grinding treatment of
a wooden surface.
4. A method according to claim 2 or 3, characterized in that the surface of the wooden door (2) or the surface of an element of a wooden door
(2) compiled of elements is the outer surface (22) of the edge board (20) of the door
(2), or part of the outer surface, such as the outer surface of the frame (20; 203)
of a frame door (2; 2c) or the outer surface of an element thereof, the edge (25a2)
of the panel (25a) of a panel element (25) of a frame door, the bottom (25a1) of a
frame door panel (25), the outer surface of the edge board (20; 201) of a form pressed
door (2; 2a), or the outer surface of an element of an edge board, or the outer surface
of an edge board (20; 202) of a flush door (2; 2b), or the outer surface of an element
of an edge board.
5. A method according to claim 4, characterized in that the outer surface (22) of at least one side of the door edge board (20) is compressed
by a rock-material piece (30), and thereafter the compressed outer surface (22) is
further treated by impregnating, spreading, rolling or spraying it at least once by
a liquid surface treatment agent, such as moisture block, preferably a water-soluble
acrylic-based paint or varnish.
6. A method according to claim 2 or 3, characterized in that the surface of the wooden door (2) or the surface of a part of the wooden door (2)
is the edge (25a2) of the panel (25a) of a panel element (25) of a frame door (2;
2c).
7. A method according to claim 1, characterized in that the method includes at least the following steps:
- a the wooden surface is set into contact with the contact surface (3) of a rock-material piece (30),
- the future wearing surface (5a) of a parquet block (5) and the contact surface (3) of the rock-material piece (30) are moved with respect to each other, and simultaneously there is created a certain homogeneous compression pressure (P) therebetween, said compression pressure being such that the wearing surface is compressed, but any wooden material, such as wood fibers, is not, however, essentially removed from the wearing surface,
- after compression, the wearing surface (5a) is treated, at the moment of treatment, by a liquid or solid coating, at least once.
8. A method according to any of the preceding claims, characterized in that the wooden surface to be treated is a wood panel surface that is treated immediately
after compression by a liquid surface treatment agent, such as a pigment, a glazing
agent, a varnish, a moisture stop and/or an anti-microbial agent and/or an agent that
preserves the physical features of the wooden surface.
9. A method according to claim 8, characterized in that the wood panel surface is treated immediately after compression by a low-viscosity
acrylate primer and/or by a low-viscosity acrylate top paint.
10. A method according to any of the preceding claims, characterized in that the contact surface (3) of the rock-material piece (30) is a planar surface and/or
a surface matched with the shapes of the wooden surface to be compressed, and that
the rock-material piece (30) is made of solid rock or that it is an alloyed rock-material
piece containing stone powder and/or stone mineral powder and/or a stone powder that
in hardness corresponds to the stone material powder, which powder is alloyed with
an adhesive medium and pressed in a desired shape.
11. A method according to claim 10, characterized in that the rock-material piece (30) is solid rock, such as gneiss, granite or soapstone.
12. A method according to claim 10, characterized in that the rock-material piece (30) is an alloyed rock-material piece, which is manufactured
by mixing the crushed stone from one or several rock types or rock-forming mineral
types and an adhesive medium, or a cement-based medium and an adhesive medium, and
possibly also an adhesion primer, such as an adhesive based on thermoplastic, that
improves the adhesion of the wood fibers onto the wooden surface to be compressed.
13. A method according to claim 12, characterized in that the rock-material piece (30) is an alloyed rock-material piece, containing an adhesive
primer for improving the adhesion of wood fibers on the wooden surface, in which method
the contact surface (3) of an alloyed rock-material piece (30) is pressed against
the wooden surface by such a force that when moving said contact surface (3) and wooden
surface with respect to each other, the rock-material piece (30) releases anti-adhesive
primer onto the wooden surface.
14. A method according to any of the preceding claims, characterized in that the contact surface of the rock-material piece (30) and the wooden surface are moved
with respect to each other in a linear fashion, and that at the same time the surface
pressure directed to the wooden surface is maintained homogeneous in the contact area
between the rock-material piece and the wooden surface.
15. The use of the method according to any of the claims 1-14 for compressing and coating
the surface of a wooden object.
16. The use of the method according to claim 15 for compressing and coating the surface
or the outer edge of a wood panel.
17. The use of the method according to claim 16, where the wood panel is a solid wood
board, a board glued of wood elements (glue board), chipboard, plywood, fiberboard,
such as MDF plate or HDF plate, or veneer plate.
18. The use of the method according to claim 17, where the wood panel is placed in the
edge board (20) or door leaf (25) or in the coating of a frame door or door leaf (25)
of a door, such as door-on-door, flush door, frame door, form pressed door, wooden
door provided with a window, a coated door, such as a flush door coated with veneer
or panel.
19. The use of the method according to claim 18, where the wood panel is a window frame,
baseboard, door frame, threshold or the surface of a piece of furniture, for instance
the surface of a kitchen table, or a parquet block.
20. A wooden surface, characterized in that it is treated by a method according to any of the claims 1-14.
21. A wooden surface according to claim 20, characterized in that the wooden surface is a the wooden surface of a wooden door (2) or the wooden surface
of part of a wooden door (2) to be manufactured, said wooden surface being treated
by one of the methods according to claims 1-6 or 8-13.
22. A wooden surface of a wooden door (2) according to claim 21, or the wooden surface
of part of a wooden door (2) to be manufactured, said wooden surface being the edge
of the wooden panel of a frame door (2; 2c) or the outer surface (22) of the frame
(20) of a frame door, or the outer surface (22) of the edge board (20) of a form pressed
door or a flush door.
23. A wooden surface according to claim 20, characterized in that it is located in a parquet block (5) treated by the method according to claim 6.
24. A wooden door (2), a wooden door provided with a window, a door-on-door, a door frame
or a door aperture threshold, characterized in that it includes a wooden surface treated by a method according to any of the claims 1-6
or 8-14.
25. A parquet block (5), characterized in that it has a wearing surface treated by a method according to any of the claims 1 or
2 or 7-12.