JPH05169406A - Method for bleaching treatment of cedar lumber - Google Patents

Abstract

PURPOSE:To improve quality of a product of a blackish cedar lumber by a method wherein resinous liq., water and air in the cedar lumber are extracted by making a pressure container wherein the cedar lumber is carried vacuum and introducing steam therein and a hydrogen peroxide soln. is poured in the pressure container and the pressure is elevated. CONSTITUTION:In the first process, a heat treatment wherein after a closed type pressure container wherein a cedar lumber is carried is made vacuum, steam is introduced therein and a pressurized condition is kept, is performed to extract a resinous liq. from the cedar lumber. In the second process, a hydrogen peroxide soln. is poured in the container and the pressurized condition is kept to inject the hydrogen peroxide soln. into the cedar lumber and after the impregnation treatment is performed, the hydrogen peroxide soln. is drawn out and then, steam is introduced and a pressurizing treatment for sustaining pressurized condition is performed to bleach the cedar lumber. In addition, in the third process, the container is made vacuum to draw out the hydrogen peroxide soln. from the cedar lumber. It is possible thereby to extract the resinous liq. from the cedar lumber by vacuum and introduction of steam in the first process, and to infiltrate the hydrogen peroxide soln. into the inside of the cedar lumber when the hydrogen peroxide soln. is poured in the second process.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for bleaching cedar wood.

[0002]

2. Description of the Related Art It is well known that cedar wood has fine grain, beautiful color and luster, and is of high quality.

Sugi logs are processed into lumber, and the products that have been carefully examined are used as cedar name wood, as veneer veneer lumber, surrounding edges, long presses, and interior materials for construction such as Kamoi.

In the cedar, the sapwood has a yellowish white color and the heartwood has a light red color, but these colors change depending on the environment at the time of growth, especially the soil quality. For this reason, there are many products that are dark in color and have low commercial value.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to enhance the commercial value of sewn cedar products by bleaching them.

[0006]

In order to solve the above-mentioned problems, in the first invention, a pressure reducing process for reducing the pressure in a closed pressure vessel into which cedar wood is carried, and steam is introduced after the pressure reducing process. The first step of removing the sap from the cedar wood by performing a heat treatment in which the pressure of the cedar wood is maintained, and the hydrogen peroxide solution is poured into the container after the first step to maintain the pressure of the cedar wood. A solution injection process of injecting a hydrogen peroxide solution into the second step and a pressure process of extracting the hydrogen peroxide solution after the injection process and then introducing steam to maintain a pressurized state are performed to bleach cedar wood. That is, a structure including a step and a third step of removing the hydrogen peroxide solution from the cedar wood by depressurizing the container after the second step is adopted.

Further, in the second invention, a decompression treatment for decompressing the sealed pressure-resistant container into which cedar wood is carried, a processing treatment for pressurizing the container after the decompression treatment, and a steam introduction after the pressure treatment. After the pretreatment process of adding water to the cedar wood,
The configuration in which the first to third steps in the first invention are sequentially performed is adopted.

[0008]

[Function] The cedar wood to be bleached has a variation in water content. When bleaching cedar wood having a water content of 73% or more, the processing method of the first invention is adopted, and cedar wood of 73% or less is used. For, the processing method of the second invention is adopted.

In the first invention, the sap can be extracted from the cedar wood by the depressurization and the steam introduction in the first step, and the hydrogen peroxide solution is injected in the second step when the hydrogen peroxide solution is injected. Can penetrate into the interior of wood. Therefore, it is possible to uniformly bleach the cedar wood throughout.

Further, in the second invention, water can be contained in the cedar wood in the pretreatment step. Therefore, the cedar wood can be uniformly bleached by sequentially treating the cedar wood after the water injection treatment in the first to third steps of the first invention.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a sealed pressure vessel used in the method of the present invention. This pressure-resistant container 1 has a lid 2 that can be opened and closed, and by closing the lid 2, the inside is kept in a sealed state.

A suction pipe 3, a water supply pipe 4 and a steam pipe 5 are connected to the pressure resistant container 1, and a vacuum pump 6 is connected to the suction pipe 3. A pressurizing pump 7 and a tank 8 are connected to the water supply pipe 4, and a boiler 9 is connected to the steam pipe 5. Further, the pressure-resistant container 1 is designed to be pressurized by a compressor (not shown).

In the bleaching treatment of the cedar wood using the pressure resistant container 1, first, the water content of the cedar wood is measured. If the water content is 73% or more, the operation is performed according to the operation schedule of the graph shown in FIG. To do.

The bleaching treatment of cedar wood having a water content of 73% or more will be described below.

First, cedar wood A is put in the perforated container 10 shown in FIG. 1, the container 10 is carried into the pressure resistant container 1, the lid 2 is closed, and the inside is sealed. In the first step, the pressure inside the pressure vessel 1 is reduced, and steam is introduced after the pressure reduction process. Decompression and introduction of steam are repeated according to the volume (thickness) of cedar wood.

The purpose of the decompression is to extract the sap, water and air from the inside of the cedar wood A, and to allow the hydrogen peroxide solution to uniformly permeate the whole cedar wood during the injection of the hydrogen peroxide solution in the subsequent process. is there.

Here, the pressure and the depressurizing time during depressurization are appropriately determined according to the volume of the cedar wood. Experimentally, the pressure is 50 to 40 torr and the time is 5 minutes to 35
Minutes are preferable.

If the pressure is 50 Torr or more, the sap, water and air cannot be completely extracted from the cedar wood, and
When it is less than or equal to Torr, the decompression force is too large, the resin is removed together with the sap, and the durability of the cedar wood is lowered, resulting in a problem that the luster is lost.

If the depressurization time is 5 minutes or less, the sap cannot be completely removed, and if it is 35 minutes or more,
Before that, the sap had completely escaped and was meaningless.

On the other hand, the purpose of introducing steam is to heat the inside of the cedar wood and facilitate the extraction of sap and water.

The temperature inside the pressure vessel 1 is 8 due to the introduction of steam.
The temperature is 0 ° C to 98 ° C, and the holding time is 10 minutes or more. 80
At a temperature of ℃ or below, it is not possible to heat the inside of the cedar wood A, and at a temperature of 98 ℃ or above, the surface of the cedar wood A is heat-burned to become black and the color cannot be corrected.

As described above, the sap inside the cedar wood A is treated by subjecting the cedar wood A to the pressure reduction treatment and the steam treatment.
Water and air can be completely drained. But,
Even if the sap is taken out, the black pigment adheres to the cedar wood A, and the original color of the cedar cannot be revealed.

Therefore, in the second step, the hydrogen peroxide solution contained in the tank 8 is supplied into the pressure resistant container 1 by the operation of the pressure pump 7 and pressurized, and after bleaching the cedar wood,
The hydrogen peroxide solution is extracted and steam is supplied instead.

The purpose of pressurizing the pressure-resistant container 1 is to:
This is because water and hydrogen peroxide solution are efficiently permeated into the cedar wood, and the pressure varies depending on the volume of the cedar wood A, but if the pressure is 8 kg / cm ² or less, the cedar wood can be made to contain water entirely. Can not. Also, at the 10 kg / cm ² or more, because there is no change in water content, pressure was 8 kg / cm ² or more, preferably, to 8kg / cm ² ~10kg / cm ² approximately.

When the pressurizing time is 5 minutes or less, the water content is insufficient, and when it is 35 minutes or more, the water content does not change. Therefore, the pressurizing time is 5 minutes or more, preferably. ,
It is about 5 to 30 minutes.

These pressure and pressurizing time are appropriately determined according to the volume of the cedar wood.

The water content of the hydrogen peroxide solution causes the cedar wood to be bleached so that the original color of the cedar can be revealed.

The introduction of steam in the second step is for facilitating the extraction of the hydrogen peroxide solution hydrated inside the cedar wood A, and the temperature inside the pressure vessel 1 due to the introduction of steam is , 80 ° C to 98 ° C as in the case of introducing steam in the first step
Then, the state is maintained for about 5 to 35 minutes.

By introducing the steam as described above, the cedar wood A is uniformly heated to the inside, and the hydrogen peroxide solution can be easily extracted.

In the third step, after the bleaching process in the pressure vessel 1, the hydrogen peroxide solution in the vessel 1 is extracted, and then the pressure vessel 1 is depressurized.

Upon depressurization, the pressure is set to 50 Torr to 40 Torr as in the first step, and the depressurized state is maintained for 5 minutes or more.

By the treatment in the third step, the hydrogen peroxide solution penetrating into the cedar wood A can be almost completely removed, and a glossy product with a beautiful color can be obtained.

When bleaching cedar wood having a water content of 73% or less, as shown in the graph of FIG. 3, cedar wood A is hydrated inside the cedar wood A by a pretreatment process, and thereafter, as described above. Bleaching is performed by sequentially performing the first to third steps.

At the time of containing water in the pretreatment step, first, the pressure-resistant container 1 is depressurized to remove the air inside the cedar wood. At this time, the pressure during depressurization is set to 50 to 40 Torr and maintained for about 5 to 35 minutes.

Next, the pressure vessel 1 is filled with water and pressurized. The pressure at the time of pressurization is 8 kg / cm ^{2 to} 10 kg / cm ² , and the time is 5
Minutes to 35 minutes. After the pressure treatment, the water in the pressure resistant container 1 is drained and steam is introduced instead. By introducing the steam, the temperature inside the pressure vessel 1 is set to 80 ° C to 98 ° C, and 10 minutes to 4 minutes.
Hold for about 0 minutes.

By the above-mentioned pretreatment, 73% or more of water can be contained in the cedar wood A. After that, the first
By sequentially performing the steps to the third step, the cedar wood A can be bleached over the entire interior in the same manner as described above. When cedar wood with a water content of 73% or less is bleached according to the schedule shown in FIG. 2, the sap extraction in the first step is incomplete, and uniform bleaching cannot be performed.

[0038]

As described above, in the bleaching treatment according to the present invention, the sap, air, and water inside the cedar wood can be completely removed in the first step, and therefore, the peroxidation in the second step is performed. The hydrogen solution can be surely penetrated inside the cedar wood. Therefore, it can be completely bleached with a hydrogen peroxide solution, and the commercial value of the product can be significantly improved.

[Brief description of drawings]

FIG. 1 is a schematic view of a pressure vessel used in the method of the present invention.

FIG. 2 is a graph showing an operation schedule

FIG. 3 is a graph showing an operation schedule

[Explanation of symbols] 1 Pressure-resistant container

Claims (2)

[Claims] 1. A sap is extracted from cedar wood by performing a depressurization process for depressurizing the closed type pressure-resistant container into which the cedar wood has been carried in and a heating process for introducing steam after the depressurization process and maintaining the pressurization state. A first step, a solution injection process of injecting a hydrogen peroxide solution into the container after the first step and maintaining the pressurized state, and injecting the hydrogen peroxide solution into the cedar wood, and a hydrogen peroxide solution after the injection process The second step of bleaching the cedar wood by performing a pressure treatment in which steam is introduced and then maintaining the pressurized state, and after the second step, the container is depressurized to remove hydrogen peroxide from the cedar wood. A method for bleaching cedar wood comprising a third step of extracting the solution. 2. A depressurization process for depressurizing the sealed pressure-resistant container into which cedar wood has been carried in, a processing process for pressurizing the container after the depressurization process, and steam after the pressurization process to introduce water into the cedar wood. A method for bleaching cedar wood, which comprises sequentially performing the first to third steps according to claim 1 after the pretreatment step to be included.