GB2177122A - Coloured fancy veneers and solid wood blocks and method of their manufacture - Google Patents

Abstract

Fancy veneers and solid wood blocks contain dyestuffs and pigments which are distributed within the wood material from faces of the wood material into its interior in the direction of its fibers and contain furthermore monosulphono dyestuffs with a molecular weight smaller than 1500 homogeneously distributed in cell walls of the wood material. According to the manufacturing method wood colouring liquid is introduced into the wood material from one or both of its faces at selected places in the direction of fibers of the wood material, with a subsequent diffusion dyeing step.

Description

SPECIFICATION Fancy veneers and solid wood blocs made from low-grade timber with unexpressivetexture or from high-grade timber, and method for their manufacture The invention relates to fancy veneers and solid wood blocs made from low-gradetimberwith unex pressive textu re a nd to a methodfortheirmanufac- ture by wood colouring liquids impregnation.

Fancy veneers and solid wood blocs with expressivetexture are actually prepared by mechanical dividing high-grade timber such as walnut, ovangkol, mahagony and othertimber species. Logs or mechanically worked out prisms with increased moisture content are generally used for manufacture of veneers. The major part of timber is priorto cutting or peeling hydrothermally plastified. Fancyveneers with expressivetexture are also manufactured by known methods from low-gradetimberwith an unexpressive texture sothatfirst peeled veneers are prepared which are coloured by a diffusion depth dyeing, whereafter they are stacked on the other and glued together to blocs by means of coloured glueing, mixtures, from which blocs veneers with a texture capable to be reproduced are subsequently cut.Processes are also known where fancy veneers are manufactured by cutting from blocs composed ofveneers, parts of veneers, paper, fibres of wooden materials and of other materials. Drawbacks of actually used manufacturing methods offancy veneers from high-grade timberarethatsimilarmaterials are more and more difficulttoobtain, particularly timber of high quality such as walnut, grenadil, ovangkol,teak, mahagony and their price is continuously substantially rising. A drawback ofveneers with a texture capable to be reproduced from veneer blocs is their semisynthetic appearance. The glued joints are visible and particu- larly atsimple, so called radial textures with bands of a width of 0.6 to 20 mm, they frequently look rather disturbingly.Another drawback is thatthe manufacture offine-lineveneers like aroveneers, leriex and lami veneers is rather troublesome.

Drawbacks ofthe present state eliminate particularly these fancy veneers and solid wood blocs from low-grade timber with unexpressive texture according to this invention, the substance of which is being represented byfancyveneersandsolidwoodblocs containing high molecular dyestuffs, colouring pigments, reactive, metal-complex, direct and acid dyestuffs and mixtures of these dyestuffs or of organig pigments with reacto-plastics,which refining agents are deposited in bands of width of 0.1-30 mm at purposeful selected places coming from faces in the direction offibres into the interior ofveneers and solid wood blocs, which wood material contains in addition monosul pho-dyestuffs with a molecular weight smallerthan 1500 homogenously distributed in situ in cell walls of veneers and solid wood blocs.

The manufacturing method of fancy veneers and solid wood blocs according to this invention consists in that into a part of one or both faces of solid wood blocs with a moisture content of 18 to 210% a wood colouring liquid is introduced at purposeful selected places of equal or different shape in direction offibres of thewood material due to a pressure difference of 0.04to 7.0 MPa at temperature between 10 and 1 0 C for 2 to 600 minutes, whereafterthe wood material of the shape of solid wood blocs orveneers its finally coloured by diffusion dyeing.

The advantage and the new effect of the object of this invention isthat it enables to prepare fancy wood material provided on a coloured background with a superposed expressive texture oriented in direction of fibres similarly as at high-grade timbers. The preparation of thins texture bases on the circumstance, thatthe ration of permeabilities between wood fibres in the longitudinal direction and between the radial-tangential direction amountsto 104to 105 and furthermore on a purposeful control of passage of wood colouring liquids by way of front faces ofthe wood material.The method according to this invention enables to provide a superposed texture on wood materials and thus to prepare and manufacture a practically untilted extent of natural refined wood materials. It is also possible to finish low-gradewood material which iseasierto obtain and is cheaper than rare and difficulttoobtain high-grade timberwith expressive texture. It is possible to refine according to this invention also high-gradetimbersothat it is similar bycolourand texture to rare wood material which is impossible or difficult to obtain.Another advantage of refining of wood material by superposing atexture in situ is, that the thus manufactured veneer orfancywood bloc represents an original which cannot be repeated as the superposed texture is achieved due to penetration of wood colouring solutions along the fibers of wood, whereby due to this penetration the original permeable passages and natural anatomic inhibitions are made outstanding orform natural permeable passages, natural anatomic inhibitions, shadows or hydraulic passages are created similarly as in case of passage of Iiquidethrough timber material in a living tissue. The system of permeable and less permeable passages and inhibitons of passage in each wood material and tree is unrepeatable and original from the point of view ofthe esthetic value.The resulting product offinishing based on their utilization represents an unrepeatable original. From the physical point of view a transformation of non-optical properties is achieved by this process such as permeability, morphological properties, particularly the distribution of different kinds offibre cells, radially oriented cells, conditions of intercellular bordered pit-pairs and of inhibitions of passage, the width and distribution of annual or growth rings, to optical properties within a spectrum of 400 to 700 nm which determine the esthetic level ofthe material.

Fancyveneersand solid wood blocsfromtimber with unexpressive texture such as poplar, aspen, alder, maple, beech,wawsorfrom high-grade timber such askoto,mahagony,ovangkol,teakcontain refining material such as synthetic polymers, oligomers, softeners and surface active materials.The veneers and solid blocs contain futhermore high molecular dyestuffs, colour pigments, reactive, metalcomplex, direct and acid dyestuffs and their mixtures or organic pigments with reactoplastics which are adjustably deposited in direction of fibres to the depth of veneers and solid blocs so that they are imitating within their whole depth and surface macrospcopical parts of annual or growth rings, of heart- and sapwood parts of resin canals and parenchymatic cells of high-grade timber. The veneers and solid wood blocs contain furthermore monosulpho-dyestuffs with a molecularweightsmallerthan 1500 distributed homogenously in situ in cell walls of veneers and solid wood blocs.

Examples of manufacturing methods of fancy veneers and solid wood blocs are indicated in the following examples: Example 1.

Prisms of beech wood/Fag ue silvatical having dimensions of 6 x 6 x 40 cm and moisturecontentof 40% are provided on both faces with a layer of epoxide resin which is allowed to be hardened for 24 hours.

After hardening the faces of prisms are provided with cuts having width of 1 cm and depth of 0.5 cm,the prisms are evacuated for 30 minutes at pressure of 0.05 MPa and are subsequently impregnated for 120 minutes at pressure of 0.6 MPa by a mixture of dyestuffs C.I.Acid Yellow 11, C.l.Acid Orange 7 and C.l.Acid Blue 62 at ratio of 1: 7 : 2.Veneers ofthickness of 0.7 mm are thereafter cut from said prisms which are provided with a coating of solution of dyestuffs C.l.Acid Orange 3, C.I.Acid Red 88 and C.I.Acid Blue 78 at ratio of :1: 1,and are heated outside the colouring solutionto a temperature of 90"Cfor8 hours in a closed space at pressure of saturated water vapors. The surface of veneers is after drying similar to mahagony.

Example 2 Prisms of koto wood /Pterigota macrocarpa/having dimensions of 6 x 6 x 40 cm and moisture content of 60% are provided on theirfaces with a coating of a suspension of polyvinyl acetate containing 15% of dry matter and are hardened attemperature of 20"6 for 3 hours. A solution of dyestuffs of C.l.Pigment Red 4 and C.l.Pigment Black 7 having a concentrationof 100 g/l is applied on both ends ofthe prism, on which the pressure of 0.6 MPa acting for 360 minutes.Veneers of 0.7 mm thickness are cut from these thus impregnated prisms.Theveneers are thereafterfinally diffusion dyed by a wood colouring liquid of a composition C.l.Acid Yellow 11, C.l.Direct Violet 46, C.l.Acid Blue 78 of a ratio 20:2:1 and 50 gl-1 of carbamide at temperature of 92 Cfor8 hours.

Example3 A prior prepared log of poplartree/Populus marilandica/having a diameter of 25cm and moisture content of 35% of fibres saturation is provided with a metal mask corresponding to the shape of annual growth rings. Thethus prepared timber is exposed to evacuationfor 30 minutes at pressure of 0.04 MPa and to the impregnation by a colouring solution of C.i.Pigment Black 7 and C.l.Pigment Red 4at ratio of 1: 7 and of200g.l1 of ethyleneglycol at pressure of 0.6 MPa for 120 minutes.Veneers of a 1.2 mm thickness are cut from the thus impregnated poplar wood which are immersed in a solution of dyestuffs of C.I.Acid Yellow 36, C.IAcid Red 88, C.I.Acid Blue 41 at ratio of 65:10:25,theveneersaredyedfor6hoursat temperature of 800C. After drying a texture is obtained similarto the ovangkol.

Example 4 A prior prepared prism of beech tree/Fagus silvatica/ having volume of 0.3m3 is steamed for24 hours to a moisture content of 190%. Theface ofthe prism is thereafter exposed to the effect of a melt of copolymerofethylenovinylacetate so that the copolymer covers the sommer part of growth rings of the wood. An impregnation solution is thereafter applied to the face of the prism consisting of C.I.Acid Black 1 having a concentration of 20 g.l-1 which acts on the prism at pressure of 0.6MPa for 120 minutes.After removal of face parts ofthe prism,the prism is again impregnated buy a colouring solution C.l.Direct Brown 1 15for2 hours art a temperature of 20"C. Afterthis impregnation fancy veneers are cut from the prism.

Example5 Into the face of a prepared log of birch tree/Betula verrucosa/metal tips having a diameter of 0.3 to 0.8 mm are pressed in, by means of which a wood colouring liquid is applied tothewood, composed of C.I.Mordant Brown 86 and C.I.Mordant Brown 95 at ratio of 1:1 at pressure of 0.6 MPa for 240 minutes.

Veneers are cut from the impregnated wooden material, which are provided with a coat of suitable colouring solutions of organic acid dyestuffs of a molecular weight 300 to 850. After application of the colouring solution in an amount of 150 to 200 g/m2the veneers are stacked on the other, are pressed to a plane by means of stainless steel plates and are situated for 24 hours in a room capableto be closed in orderto prevent evacuation of water. The colouring solution is left to diffuse attemperaturewithin 60to 90 C for 24 hours, theveneers are thereafter dried to a moisture content of8 to 12%. Veneers with an expressive decorative texture are thus obtained.

Example 6 A prepared prism of hornbeam wood/Carpinus betulus/ is impregnated for 1 minute by immersion in a 33% aqueous solution of sodium silicate with a following hardening for 10 hours, whereafterthefaces are ground. The thus prepared prism is subsequently impregnated in a wood colouring liquid containing 40 9.1- of dyestuffsAcid Black 52. The cut veneers are therefore diffusion dyed by a wood colouring liquid of a composition of C.l.Acid Brown 19 having a concentration of 40 g.l-1 and of a copolymer of propylene oxideand ethylene oxide having a concentration of 10 g.l-l at temperature of 90 C for 8 hours. The thus treated veneers have a texture similarto palisander wood.

Example 7 Prepared prisms of li me wood /Ti lia cordatal having dimensions of 6 x 6 x 40 cm are bytheirfaces exposed forthe shorttime effect of 25 seconds to an alloyof lead, tin, bismuth and cadmium at ratio of 2:4 :4:1 attemperature of 1 50C. The thus prepared prisms are impregnated by a colouring solution of C.l.Pigment Black 7 and C.l.Pigment Red 4 at ratio of 1: 1 at pressure of 0.8MPs for 180 minutes. by cutting the prisms to veneers a decorative material is obtained.

Example 8 Faces of a prepared prismofpoplartree/Populus mariladica/ are provided with a coat of copolymer of styrene and esterofacrylicacid, and one ofthesefaces is exposed to the action of 0.04 MPa vacuum, the other to the pressure of a wood colouring liquid composed ofC.LPigment Black7 at pressure of 0.5 MPa for 120 minutes. Veneers are cut from the prism, into which a colouring solution containing C.I.Acid Orange 3, C.l.Acid Red 88 and C.I.Acid Blue 78 at ratio of 10 : 2:1 is allowed to diffuse in a mixturewithadispersionof copolymer of vinylacetate and ester of acrylic acid with a dry content of 55% for 8 hours.The obtained veneersare dried attemperature of 85 Cfor25 minutes. Theirtexture is similar the ovangkol wood.

Example 9 Prisms of poplarwood /Popupus marilandical having dimensions of 6 x 6 x 40 cm and moisture content of 20% are at their faces provided with a coating of glass particles sized from 10-4to2.10-3,the thus prepared wooden material is evacuated for 30 minutes at pressure of 0.06 MPa and is subsequently impregnated by a colouring solution of C.I.Pigment Black 7 having concentration of 100 g.l1 for 120 minutes. Afterthis impregnation veneers of 0.7 mm thickness are cut from the prism and are immersed in a solution of dyestuffs C.l.Acid Yellow 11, C.I.Acid Orange 10 and C.I.Acid Blue 40 at ratio of 10:1.5:1.

The veneers are dyed for 6 hours at temperature of 80 C and after drying a fancy veneer is obtained with a decorative texture similar to ovangkol wood.

The fancy veneers and solid wood blocs treated according to this invention and the methodfortheir manufacture can be utilized for manufacture of furnitu re, for lini ng and for all purposes where the decorative effect of wood is utilized.

Claims (7)

1. Fancyveneers and solid wood blocs made from low-grade timber with unexpressive texture or from high-grade timber, comprising refining agents such as synthetic polymers, oligomers, softeners andmaterials acting on the surface, which veneers and solid wood blocs comprise in addition materials such as high molecular dyestuffs, colour pigments, reactive metal-complex, direct and acid dyestuffs and their mixtures or organic pigments with reactoplastics, which materials are deposited in bands of width of 0.1 to 30 mm coming from faces in the direction of fibers into the interior of veneers and solid wood blocs and comprising furthermore monosulpho-dyestuffwith a molecularweightsmallerthan 1500 homogenoualy distributed in situ in cell walls of veneers and solid wood blocs.

2. Method for manufacture of fancy veneers and solid wood blocs from low-gradetimberwith unex pressive texture orfrom high-grade timber as in claim 1 by impregnation by wood colouring modification materials such as aqueous and organic solutions of acid, metal-complex or reactive dyestuffs, colour pigments, solution mixtures of dyestuffs with reactoplastics, thermoplastics, oligomers, monomers, softeners and other auxiliar industrial materials where to a part of one or of both faces of the wood material having moisture content of 18 to 210% at internationally prior selected places ofthe same or different shape awood colouring liquid is introduced dueto pressure difference of 0.04to 7.0 MPa attemperature of lotto 1 10'Cfor2tiII 600 minutes in direction of wood fibres, whereafter the wood material in the shape of veneers or solid wood blocs is finally coloured by diffusion dyeing.

3. Method for manufacture of fancy veneers and solid wood blocs from low-gradetimberwith unex pressivetexture orfrom high-grade timber as in claim 2 where the intentionally prior selected places for introduction of wood colouring liquids are obtained by closing atone or both faces of the wood material of lumina parts of liquid carrying cells by mechanical plugging.

4. Method for manufacture offancy veneers and solid wood blocs from low-gradetimberwith unex pressive texture orfrom high-gradetimberasinclaim 2 and 3, where the closing of faces is accomplished by application of a coating of colloidal systems of a particle size from 10-8 to 10-3 m which form semipermeable diaphragms such as polyvinylacetate and acrylate dispersions and gels of silicic acid for 0.5 to 300 seconds at pressures from 0.1 to 0.7 MPa at temperature from 15 to 35 C whereafterthe dispersion is hardened.

5. Method four manufacture of fancy veneers and solid wood blocs as in claim 2 and 3 where the closing is accomplished by impregnation of faces by metals with low melting point such as alloy of lead, tin, bismuth and cadmium within 0.5 to 25 seconds at temperature from 110 to 3000C.

6. Fancyveneers and solid wood blocs as claimed in Claim 1, substantially as hereinbefore described.

7. Method as claimed in Claim 2, substantially as described in any one of the examples.