JPS6027501A - Method of bleaching veneer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a bleaching method for removing local stains and coloring from the surface of wood such as veneer or sawn wood to achieve a uniform color.

[Prior art and its problems]

Conventionally, methods for bleaching such veneers include applying a bleaching solution to the aqueous surface or immersing the veneer in a bleaching solution.

However, with the method of applying bleaching solution to the surface of the veneer, due to the coarseness and density of the local structure of the wood, the resin content of the wood, etc.
Differences in suction and uneven application of the bleaching solution may occur, resulting in uneven bleaching, or only a small portion of the surface of the veneer may be bleached, leaving the inside unbleached, resulting in the veneer being damaged in a later process. Even if the surface is slightly polished, the unbleached parts inside will still be visible.

In addition, in the method of immersing the veneer in a bleaching solution, the surfaces of the veneers stick to each other in the bleaching solution, and the areas that are in close contact with each other are less likely to be bleached due to poor diffusion of the bleaching solution. As a result, only the solution in contact with the veneer performs the bleaching action, resulting in poor bleaching efficiency and the need for a large amount of bleaching solution as not all the bleaching solution can be used effectively. There were problems such as the need to have many waste liquid treatment facilities in order to treat the liquid whose bleaching efficiency has deteriorated.

[Purpose of the invention]

An object of the present invention is to solve the problems of the prior art as described above, and to provide a method for safely bleaching the interior of a veneer using the minimum necessary amount of bleaching solution and with a simple operation. It is in.

[Structure of the invention]

In order to achieve the following object, in the present invention, the entire veneer to which the bleaching solution has been applied is coated with a synthetic resin film, then pressurized as it is, and then heated and cured after the pressure is removed.

The veneer to be treated in the present invention is a normal irrigation veneer having a thickness in the range of about 0.2U+ to 21 mm, and may be dried or undried.

The bleaching solution used in the present invention includes an aqueous solution of ordinary bleaching agents such as hydrogen peroxide, sodium peroxide, peracetic acid, sodium hypochlorite, sodium chlorite, and white powder with various interfacial ρi properties. A catalyst such as sodium hydroxide, ammonia, or sodium tripolyphosphate to a mixture of one or more agents such as polyoxyethylene alkyl ether, sulfuric acid ester salt of polyoxyalkylene alkylphenol, and alkyl sulfonic acid of higher fatty acid amide; Furthermore, it is possible to use a solution containing a decomposition regulator such as sodium silicate.

Methods for adhering the bleaching solution to the surface of the veneer include dipping the veneers one by one in a vat containing a small amount of the solution, or using a spreader to apply the solution to the surface of the veneer. method can be adopted.

The standard amount of bleaching solution applied to the veneer is preferably about 70% to 150% of the weight of the dry veneer.

Furthermore, in the present invention, after a bleaching solution is applied to the surface of the veneers, the veneers are placed together and the whole is covered with a synthetic resin film having excellent chemical resistance. This is done in order to minimize the amount of bleaching solution used and to prevent the oxygen and chlorine gases that are produced by the bleaching agent from escaping from around the veneer for as long as possible. .

Synthetic resin films with excellent chemical resistance used to cover veneers are made of polyethylene resin, polypropylene resin, vinyl chloride resin, vinylidene chloride resin, etc., and have a thickness of about O, O11 to 1, Ots. use something

Next, the cH plate entirely covered with a synthetic resin film is sealed in a pressure-resistant container that can be pressurized, and pressurized air is introduced to keep it in a pressurized state.

Pressure conditions are 5-20 kg/cf and 30-6
It may take about 0 minutes, during which time the bleaching solution is sufficiently penetrated into the veneer.

Then, the pressure inside the container is removed, and the stacked veneers, whose outsides are covered with a synthetic resin film, are taken out from the container and heated and cured in that state.

The curing conditions are maintained at a temperature of 50 to 70° C. for about 24 to 48 hours to accelerate the decomposition reaction of the bleaching agent immersed in the veneer and sufficiently bleach the veneer.

〔Example〕

Hereinafter, examples of the present invention will be described.

Example 1 A spreader was used to apply 200 g of a bleaching solution to each dry veneer of the Ayuse phase measuring 0.7mm thick x 350mm wide x 1850mm long.

The composition of the bleaching solution is as follows.

Composition of bleaching solution (in IJL) Hydrogen peroxide solution (35% product) 100 g Sodium hydroxide (flake) 20 g Alcohol sulfonate 108 Sodium silicate 30 g Water 840 g Next, 1000 of the veneers were stacked together. After sealing with polyethylene film, it is sealed in a pressurizable container with a diameter of 1 m and a length of 2 m, and pressurized air is introduced to generate a pressure of 15 kg/ci.
The pressure was maintained for 60 minutes to allow the bleaching solution to penetrate into the inside of the veneer.

Subsequently, these veneers were taken out of the container and left as they were in a constant temperature room at 60° C. for 48 hours, resulting in Ayuse moon veneers that were completely bleached to the inside.

Example 2 A bleaching solution of 200 g per piece was applied to undried Agadis wood veneer (moisture content of about 50-100%) of J7 length 0.5 x width 350 x length 1850. Example 1 I was dressed in the same manner as above.

The composition of the bleaching solution is as follows.

Composition of bleaching solution (in fIl) iI! J hydrogen oxide solution (35% product) 200 g Sodium hydroxide (flake) 30 g Polyoxyethylene alkyl ether 10 g Sodium silicate 5 g Water 710 g Then, these veneers were bleached by the same treatment method as in Example 1. As a result, we obtained agathis wood veneer that was completely bleached inside.

〔Effect of the invention〕

The effects of the present invention are listed below.

11) Compared to conventional bleaching methods such as dipping, less residual bleaching solution is required, making it economical and helping to prevent pollution caused by waste solution.

(2) Since not only dried veneers but also undried veneers can be bleached, there is no need to dry the veneers beforehand, resulting in energy savings.

(3) Since the entire veneer is covered with a synthetic resin film, the generated oxygen and chlorine are difficult to scatter to the surrounding area, and the bleaching effect is high.

+4) Since the amount of bleaching solution used is small, it is not only economical, but also safe even if a reaction suddenly occurs.

Patent distributor Danya Sangyo Co., Ltd. Agent Masu Kobori (and 2 others)

Claims (1)

[Claims] 1. After applying a bleaching solution to the surface of the veneers, the veneers are stacked together, the whole is covered with a chemical-resistant synthetic resin film, and the veneers are sealed in a pressurized container and kept under pressure. , remove the pressure and take out the stacked veneers from the container,
A method for bleaching a veneer, which comprises then heating and curing the veneer while covering it with a chemical-resistant synthetic resin film.