JPS6363363B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for dyeing wood.

Dyeing of wood, particularly wood veneers used in the production of laminated decorative veneers, has hitherto been carried out by a dip dyeing method. However, this method has drawbacks such as a long dyeing time, large variations in dyeing, and large energy loss due to the large bath ratio. As a result of repeated research in order to develop a dyeing method that does not have the above-mentioned drawbacks, the inventors of the present invention decided to apply a dye bath solution onto the surface of a wooden veneer and repeatedly heat and cool it. The inventors have discovered that it is possible to dye wood veneers without causing the above-mentioned drawbacks, and have arrived at this invention.

That is, the gist of the present invention is to apply a dye solution to the surface of wood, and to alternately and repeatedly apply heating and rapid cooling to the surface of the wood.

Next, this invention will be explained in detail based on one example.

That is, as shown in the drawing, a dye solution 2 is applied to the surface of a wooden veneer by passing it between coating rolls 1. Next, this is fed into a heating zone 3 and heated, and then passed between cooling rolls 4 to be cooled. Then, heating by the heating zone 3 and cooling by the cooling roll 4 are further performed. In this way,
Repeat heating and rapid cooling alternately. As a result, the dye solution applied to the surface of the wood veneer uniformly penetrates into the interior of the wood veneer in a short time, resulting in rapid and uniform dyeing.

The coating roll 1 used when applying the dye solution to the surface of the wood veneer as described above is as follows:
A normal roll coater is used. The concentration of the dye solution to be applied is set depending on the purpose, but a thickener such as commercially available carboxymethyl cellulose (CMC) or sodium alginate is added as necessary to adjust the viscosity.

Steam is normally used for heating in the heating zone 3 in order to prevent moisture in the veneer from evaporating as much as possible. The higher the heating temperature, the faster and more uniformly the dye solution will penetrate. In this case, it is preferable to use steam heating and microwave heating in combination because the veneer can be heated more quickly and uniformly.

For cooling by the cooling rolls 4, it is preferable to arrange a plurality of cooling rolls 4 side by side in the horizontal direction so that the cooling rolls 4 are passed through the cooling rolls 4 in order to speed up the cooling. The temperature of the cooling roll 4 is usually set at 40° C. or lower in terms of effectiveness.

Note that the means for applying, heating, and rapidly cooling the dye solution are not limited to those described above, and commonly used means can be used as appropriate.

As described above, in the present invention, a dye solution is applied to the surface of wood, and heating and rapid cooling are alternately repeated, so that uniform dyeing can be quickly performed. Furthermore, since this dyeing method applies a dye solution directly to the wood surface for dyeing, there is no energy loss as in the case of dip dyeing, and energy savings can be achieved. The reason why such an effect is obtained is considered to be due to the following reasons. That is, in a simple application method in which a dye solution is applied to the wood surface and left to dry, the dye remains near the surface of the wood and does not easily penetrate and diffuse into the interior of the wood. Therefore, when wood is heated, the activity of dye molecules increases, and the dye quickly penetrates into the wood at the beginning of heating. However, once the dye has penetrated into the wood to some extent, the dye penetration efficiency decreases, and even if additional heating time is spent, the dye will not penetrate as much. This seems to be because the activity of the dye that has penetrated into the wood is high, which has the effect of preventing the penetration of subsequent dyes.

However, in the case of this invention, once the dye has penetrated into the wood to some extent after a certain heating time, the dye that has penetrated into the wood is fixed at that location by rapidly cooling the wood. be able to. If the wood is then heated again, the dye that is newly penetrating into the interior of the wood from the surface will be able to penetrate and diffuse as efficiently as in the initial stage of heating, without being hindered by the dye inside.

Therefore, it is thought that by repeating heating and rapid cooling as described above, the dye permeates and diffuses into the interior of the wood very efficiently, resulting in rapid and uniform dyeing. In particular, when cooling is performed using cooling rolls, the cooling effect is much higher and faster than simply cooling, and the pressure applied by the rolls is also applied.
Penetration of the dye solution progresses more efficiently and processing time can be further shortened.

Next, examples will be described.

〔Example〕

A commercially available acid dye aqueous solution was applied to a 1.0 mm thick Labra rotary veneer, and the mixture was exposed to water vapor.
It was heated for 5 minutes by irradiating microwaves at 2450MHz. Next, this was passed through a cooling roll to lower the temperature to 35°C. In this way, the heating and cooling treatments were alternately repeated three times. As a result, the dyed veneer obtained was uniformly dyed to the inside.

Incidentally, in order to obtain a dyed veneer with the same degree of staining using the dipping method, staining at 95°C for 3 hours was required.

[Brief explanation of drawings]

The drawing is an explanatory diagram of an example of the present invention. 1... Application roll, 2... Dye solution, 3... Heating zone, 4... Cooling roll.

Claims (1)

[Scope of Claims] 1. A method for dyeing wood, which comprises applying a dye solution to the surface of wood and alternately and repeatedly applying heating and rapid cooling. 2. The method for dyeing wood according to claim 1, wherein the wood is a wood veneer. 3 Apply the dye solution using a coating roll,
Claim 1 in which the heating is performed using steam and the rapid cooling is performed using a cooling roll.
Methods of staining wood as described in section. 4. The method for dyeing wood according to claim 3, in which heating with microwaves is also performed at the time of heating with water vapor.