CS221008B1 - A method of coloring sets of veneer materials - Google Patents

Abstract

. A method of dyeing sets of veneer materials with increased circulation of the dye solution between individual veneers. ;: Dřevařsky · The purpose of the invention is to increase the intensity of the flow of the dye solution between the veneers, thereby achieving the elimination or substantial reduction of the occurrence of insufficiently overdyed veneers that have been dyed using existing dyeing methods. The stated purpose of the invention is achieved by injecting dispersed gases immiscible or limitedly miscible with the dyeing bath such as inert gases, their mixtures with air or air or mixtures of said gases with water vapor into the dyeing bath under the lower edges of the veneer sheets.

Description

The invention solves the method of dyeing sets of veneer materials with increased circulation of the dyeing solution between individual veneers.

To date, methods of deep staining of veneers in assemblies by vacuum-pressure impregnation or by simply heating the veneers in a circulating staining solution are known. The temperature during deep impregnation of veneers is usually in the range of 80-95 ° C under pressure-less impregnation and up to 120 degrees Celsius under pressure or vacuum-pressure impregnation. During the dyeing, the veneers are stacked on top of each other, or a spacer material with holes or mesh is placed between the individual veneers.

The dyeing process takes several hours. The disadvantage of these processes is that at the points of contact of the veneer or the veneer with the spacer materials or the auxiliary materials of the veneer support or with other parts of the coloring device, the coloring solution flows less intensively or is stopped. Therefore, the concentration of dyes is significantly reduced at these sites due to the diffusion of dyes from the surface of the inside of the veneer sheet. Therefore, these contact points are unevenly, less intensely colored than the other parts of the veneer.

These defects often occur when dyeing veneers of 0.5 to 0.9 mm thick woody species such as wawa (abachi, obeche, samba) - Triplochiton scleroxylon, poplar - Populus marilandica, Populus nigra, etc. - and even more difficulties arise with dyeing harder wood species such as koto (awari, shrubs) - Ptarygota, macrocarpa, beech - Fagus silvatica, limba - Terminalia superba and the like, and dyeing of larger thicknesses, for example in the range 0.9 to 3 mm.

The aforementioned drawbacks of the known processes are largely eliminated by the method of dyeing veneer material assemblies according to the invention, which consists in injecting dispersed gases immiscible or limitedly miscible with a dye bath, such as inert gases, into the dyeing bath below the lower edges of the veneer sheets. air, or air, or mixtures of said gases with water vapor.

An advantage of said method of coloring veneers is that the gas supplied under the veneer and flowing between the veneers qualitatively increases the flow rate of the coloring solution. The gas stream causes the veneer sheets to move and thus slightly separates from each other and balances the coloring solution concentrations at the locations of accidental contact of the veneers with the average concentration of the coloring bath. This achieves the elimination or substantial reduction of the occurrence of insufficiently colored areas.

Example 1

Wawa veneers - Triplochiton scleroxylon 0.9 mm thick with humidity w = 12 + 3% were immersed in an aqueous solution of a mixture of acidic monosulfo dyes with a total concentration c _F = 1.56 g / l, heated to 95 + 2 ° C . Nitrogen was blown into the dye bath at a temperature of 95 ° C under the lower edges of the veneers. The nitrogen stream was evenly distributed between the veneers by means of a ceramic plate with 5 mm diameter holes.

Example 2

750 m ^{2 of} 600X2200 mm wawa wood veneer of 0.9 mm thickness, hydromodule Hc = 4.3 1 / m ² were inserted into the 3500 l dyeing space, with a veneer filling rate of kv = 1 (85 mm) mm ^-1 (in millimeters of free space per 1 mm of wood material depth), ie 54%. Dyeed to mahogany color. The dyeing was carried out at a temperature of t = 94.5 + 1 ° C for 6 hours while the dye was circulating. solution Q = 18.4 l / s In a batch without gas supply, veneers were obtained with occurrence of weaker pre-painted spots ranging from 65 to 99% of the total number of veneer sheets (in each part of the support), the area of less pre-painted spots being 1, 3 to 12% of the total stained area in each veneer support partition.

Example 3

The dyeing was performed as in Example 2 except that after immersion of the veneer carrier in the dye bath, nitrogen was bubbled through the dye bath at the dyeing temperature t = 94.5 + 2 ° C for 2 minutes while circulating the dye bath. . Then the nitrogen supply was stopped, the mixture of nitrogen and water vapor and air residue was pumped from above the coloring bath level and fed under the lower edges of the veneer sheets where it was dispersed by means of a mechanical baffle with openings in which the foils were placed vertically. The gas supply was approximately the same Q - 4 l / s throughout the dyeing period. example

The staining was carried out as in example no. Except that a mixture of air and water vapor was pumped from the sealed space above the dye solution and injected into the dye solution under veneer at intervals of 4 + 1.5 s, with an air supply interruption interval for the first hour of dyeing. was 5 s, for 2 h 5 min, and for 3-6 h staining 10 min. Less colored areas occurred only at 6 ° / o veneer count. The average color difference between defects and well colored spots in the GIE LAB-1976 system is Δ E = 4.5.

Example 5

700 x 2200 mm veneers with a thickness of 0.8 mm were placed in 7 sets of 60 pieces each and placed in 7 veneer barriers such that the wood mass was filled with 52% of the carrier volume. The carrier was placed in a tracing dye bath of acidic moriosulfo dyes and dichlorotriazine reactive dyes heated to 98 ° C. During this batch, a zinc-enriched air and water vapor stream was pumped through the dye solution, using a self-regulated cyclic bubbling with a total cycle time of 7 s, with a bubble bath bubbling time of 3 to 5 seconds. up to 4 s.

The automatic cycle control was performed so that both the dye solution and the gas were pumped through the interior of the dyeing tank filled with veneers, then the gas was separated from the liquid by means of an overflow at the top of the tank. Next, the liquid was drained from the liquid overflow to the suction section of the pump located below the overflow. The level was adjusted so that it equaled the amount that the pump pumped at the pin power in 5 seconds. After 8 hours of dyeing, veneers colored throughout the mass were obtained.

Said method of dyeing can be used for dyeing veneers and in particular for dyeing such veneers which are subsequently compressed into blocks for producing reproducible veneers. It can also be used in the preparation of beautiful veneers colored only to a certain depth, with the advantage that such a color veneer can eliminate the problem of deteriorating the quality of products by grinding, as is the case with surface stained veneers. The method can also be used as a first stage of a shortened mushroom refinement of wood materials with organic dyes, wetting agents, synthetic resins, and the like.

Claims (3)

Example 5 Veneers of 700 x 2200 mm with a thickness of 0.8 mm were placed in 7 sets of 60 pieces placed in 7 veneer partitions of the veneer so that the mass was filled with 52% of the volume of the carrier. The carrier was charged to a circulating dyeing bath of 98 ° C acidic mohosulfofaric dyes of dichlorotriazine reactive dyes. During this batch, through the staining solution, nitrogen-enriched air and water vapors were pumped in, using a self-controlled cyclic bubbling with a total cycle time of 7 s, with the bubbling time of the bath in one cycle being 3-5, and the gas-phase pumping color solution was 2-4 s. A self-regulating cycle is carried out when both the dyeing solution and the gas are pumped from the interior of the nozzle-filled dyeing tank, then the gas is separated from the liquid by the overflow at the top of the tank. Another liquid is removed from the liquid overflow into the suction section of the pump located under the overflow. The volume level is set to be equal to the amount that the pump performs in full in 5 seconds. After 8 hours of dyeing, dyed dyestuffs were obtained throughout the mass. Said manner of dyeing is used for deep coloring of veneers and, in general, for the dyeing of veneers which are subsequently pressed into blocks for the production of reproducible veneers. It can also be used in the preparation of θ'-beautiful veneers, colored only to a certain depth, with the advantage that the problem of deterioration in the quality of the products by sanding such as a surface-stained veneer can be avoided in such color veneers. The method is also utilized as a first step of shortened depth tempering of wood materials with organic dyes, plasticizers, synthetic resins and the like. OBJECT CLAIMS 1. A method for dyeing sets of veneer materials with increased circulation of a coloring solution between individual veneers, the strips arranged parallel to each other, with the main surfaces of veneers oriented horizontally, in a closed space with a level of circulating dyeing solution, characterized in that In the dyeing bath, diffuse gases, immiscible or limited, with the dyeing wheel, such as the internal gases or mixtures thereof with air or air or mixtures of the said gases with water vapor, inject under the edges of the veneer sheets. 2. A method for dyeing sets of veneer materials, as described in paragraph 1, characterized by the fact that the gases are pumped into the surface, subsequently compressed, allowed to expand into a dyeing bath, and pumped again after the veneer moldings and over the dyeing bath level. in a narrow circulation circuit to a dyeing column. 3. A method for dyeing sets of veneer materials according to claim 1, wherein the gases are introduced into the bath at intervals of 2 to 25 seconds, with an interruption of the gas supply in the range of 0.05 to 25 minutes, wherein the interval is advantageously extended with advancing timing.