JP3197206U - Bleached plywood manufacturing system and bleached plywood - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure a sufficient time after applying a bleaching solution and effectively utilize the residual heat of a hot press machine to promote a bleaching action and sufficiently dry the bleaching solution to uniformly bleach a plywood. A bleaching plywood manufacturing system, a bleaching liquid manufacturing system, and a bleaching plywood are provided. SOLUTION: A hot press machine 12 for forming a plywood by heat-pressing two plate materials coated with an adhesive, and a bleaching liquid application for applying a bleaching solution to the surface of the plywood where the residual heat of the hot press machine 12 remains. A plurality of supports 14b that support the machine 13 and the plywood coated with the bleaching solution obliquely are spaced apart from the surface of the endless belt 14a that is rotationally driven by a distance larger than the thickness of the plywood along the conveying direction. And a bleach-drying conveyor 14 provided. [Selection] Figure 2

Description

  The present invention relates to a bleaching plywood manufacturing system, a bleaching solution manufacturing system, and a bleaching plywood suitable for bleaching wood such as Chinese plywood and natural wood flooring.

  Even if the wood is the same tree species, the material color is different for each tree, and even if the wood is the same, the material color is different between the core portion and the peripheral portion. For this reason, when the wood is processed into a wall material or a floor material as it is, since the material colors are different, a lot of wood that is difficult to use as a product that requires a sense of unity is discarded.

  Therefore, conventionally, a technique is known in which wood is bleached using a predetermined bleaching solution to suppress variations in material colors. For example, in Japanese Patent Laid-Open No. 3-65301, immediately after forming a glued veneer veneer with a hot press machine to form a single plywood, a hydrogen peroxide solution is applied to the desired surface of the plywood. A technique for bleaching is disclosed (Patent Document 1).

Japanese Patent Laid-Open No. 3-65301

  However, in Patent Document 1 described above, the veneer plywood sprayed with the hydrogen peroxide solution is immediately sent to the lifter and laminated one after another (FIG. 2). For this reason, there is little time until the other veneer plywood is laminated after the hydrogen peroxide solution is sprayed, and the remaining heat from the hot press machine is not fully utilized. Therefore, the bleaching action may be uneven, or the hydrogen peroxide solution may not be sufficiently dried.

  The present invention has been made to solve such problems, and ensures a sufficient time after applying the bleaching solution and promotes the bleaching action by effectively using the residual heat of the hot press machine. It is another object of the present invention to provide a bleaching plywood manufacturing system, a bleaching solution manufacturing system, and a bleaching plywood that can sufficiently dry the bleaching liquid and uniformly bleach the plywood.

  A bleaching plywood manufacturing system according to the present invention includes a hot press machine that forms a plywood by thermocompression bonding two board materials coated with an adhesive, and a bleaching solution on the surface of the plywood where residual heat of the hot press machine remains. And a plurality of supports that support the plywood coated with the bleaching solution at an angle from the thickness of the plywood along the conveying direction on the surface of the endless belt that is rotationally driven. And a bleach-drying conveyor provided at a large interval.

  Further, as one aspect of the present invention, the bleaching solution coating machine includes a bleaching solution coating roller that coats a bleaching solution on the surface of the plywood, and a spray nozzle that sprays the bleaching solution onto the bleaching solution coating roller. It may be.

  Furthermore, as one aspect of the present invention, the bleaching plywood manufacturing system includes a bleaching solution supply device that supplies the bleaching solution to the bleaching solution coating machine, and the bleaching solution supply device includes the spray nozzle on the spray nozzle. A bleaching solution tank that supplies bleaching solution, an air supply solenoid valve that supplies compressed air from a compressor into the bleaching solution tank, and an exhaust solenoid valve that exhausts compressed air in the bleaching solution tank. You may have.

  Further, the bleaching solution manufacturing system according to the present invention includes a hydrogen peroxide solution tank for storing hydrogen peroxide solution, a sodium metasilicate tank for storing sodium metasilicate aqueous solution, a soft water tank for storing soft water, and the metasilicate solution. A mixed liquid tank for storing a mixed solution of an aqueous sodium solution and the soft water, a mixer for mixing the hydrogen peroxide solution and the mixed liquid, and a bleaching liquid tank for storing the bleached liquid mixed in the mixer; Have.

  Further, as one aspect of the present invention, a sodium metasilicate valve for measuring the sodium metasilicate aqueous solution supplied from the sodium metasilicate tank to the mixed liquid tank, and the soft water tank supplied to the mixed liquid tank A soft water valve for metering soft water, a hydrogen peroxide pump for supplying a predetermined amount of the hydrogen peroxide solution from the hydrogen peroxide solution tank, and a liquid mixture pump for supplying a predetermined amount of the liquid mixture from the liquid mixture tank And may have.

  Furthermore, as one aspect of the present invention, the mixer may be configured by a pipe formed in a spiral shape.

  The bleaching plywood according to the present invention is bleached with a bleaching solution in which a mixed solution of a sodium metasilicate aqueous solution and soft water is mixed with a hydrogen peroxide solution.

  Moreover, as one aspect of the present invention, in the bleaching solution, the blending ratio of the sodium metasilicate aqueous solution is 10 to 15% by mass, the blending ratio of the soft water is 60 to 70% by mass, and the hydrogen peroxide solution The blending ratio of may be 20 to 25% by mass.

  According to the present invention, sufficient time is ensured after the bleaching solution is applied, and the bleaching action is promoted by effectively utilizing the residual heat of the hot press machine, and the bleaching solution is sufficiently dried to uniformly bleach the plywood. can do.

1 is an overall view showing an embodiment of a bleaching solution manufacturing system according to the present invention. 1 is an overall view showing an embodiment of a bleached plywood manufacturing system according to the present invention.

  Hereinafter, an embodiment of a bleaching plywood manufacturing system, a bleaching solution manufacturing system, and a bleaching plywood according to the present invention will be described with reference to the drawings.

  First, a bleaching solution manufacturing system 1 according to the present embodiment is for manufacturing a bleaching solution for bleaching wood. As shown in FIG. 1, mainly a hydrogen peroxide tank 2 and metasilicic acid. Mixing in the sodium tank 3, the soft water tank 4, the liquid mixture tank 5 for storing the liquid mixture of the sodium metasilicate aqueous solution and the soft water, the mixer 6 for mixing the hydrogen peroxide solution and the liquid mixture, and the mixer 6 A bleaching solution tank 7 for storing the bleaching solution. Each configuration will be described below.

  In the present embodiment, the wood is formed by bonding a single plate as a surface material to a base plate as a base, such as China plywood or natural wood flooring, but is limited to this configuration. It is not a thing. Further, examples of tree species that can be bleached include, but are not limited to, China, Hippo, Oak, Sen, Beech, Maple, Oak, Ash, and the like.

  The hydrogen peroxide tank 2 stores a hydrogen peroxide solution that is a main component of the bleaching solution. In the present embodiment, as shown in FIG. 1, a hydrogen peroxide solution pump 2 a composed of a metering pump is connected to the hydrogen peroxide solution tank 2. A predetermined amount of hydrogen peroxide solution is supplied from the hydrogen peroxide solution tank 2 to the mixer 6 by the hydrogen peroxide solution pump 2a.

  The sodium metasilicate tank 3 stores a sodium metasilicate aqueous solution for promoting the bleaching action of the hydrogen peroxide solution. In this embodiment, as shown in FIG. 1, a predetermined amount of sodium metasilicate is obtained by opening and closing a sodium metasilicate valve 3a capable of measuring an aqueous solution of sodium metasilicate supplied from the sodium metasilicate tank 3 to the mixed solution tank 5. An aqueous solution is supplied to the mixed solution tank 5.

  The soft water tank 4 stores soft water for diluting the bleaching solution. In the present embodiment, as shown in FIG. 1, a predetermined amount of soft water is supplied to the mixed liquid tank 5 by opening and closing a soft water valve 4 a that measures the soft water supplied from the soft water tank 4 to the mixed liquid tank 5. It has become. Further, in the present embodiment, soft water is obtained by replacing calcium ions and magnesium ions contained in water with sodium ions by the action of an ion exchange resin.

  The mixed liquid tank 5 stores a mixed liquid of an aqueous sodium metasilicate solution and soft water. In the present embodiment, as shown in FIG. 1, a mixed liquid pump 5 a composed of a metering pump is connected to the mixed liquid tank 5. A predetermined amount of the mixed liquid is supplied from the mixed liquid tank 5 to the mixer 6 by the mixed liquid pump 5a.

  The mixer 6 mixes a hydrogen peroxide solution and a mixed solution to make a bleaching solution. In the present embodiment, as shown in FIG. 1, the mixer 6 is constituted by a pipe formed in a spiral shape, so that the hydrogen peroxide solution and the mixed solution can be uniformly mixed.

  The bleaching solution tank 7 stores the bleaching solution mixed in the mixer 6. In the present embodiment, the bleaching solution tank 7 is automatically metered and supplied with the bleaching solution for one cycle (for 10 to 30 plywood) by the hydrogen peroxide pump 2a and the mixed solution pump 5a. ing.

  Below, the effect | action at the time of manufacturing a bleaching liquid using the bleaching liquid manufacturing system 1 of this embodiment mentioned above is demonstrated.

  First, a predetermined amount of aqueous sodium metasilicate solution is supplied from the sodium metasilicate tank 3 to the mixed liquid tank 5 using the sodium metasilicate valve 3 a. Further, a predetermined amount of soft water is supplied from the soft water tank 4 to the mixed liquid tank 5 using the soft water valve 4 a. Thus, by providing the liquid mixture tank 5 separately, the mixing ratio of the sodium metasilicate aqueous solution and the soft water can be easily adjusted. For this reason, the mixing ratio is adjusted according to the tree species to be bleached. For example, when bleaching Chinese plywood, it is possible to bleach with emphasis on the grain by preparing a large amount of sodium metasilicate aqueous solution.

  Next, a predetermined amount of hydrogen peroxide solution is supplied from the hydrogen peroxide solution tank 2 to the mixer 6 via the hydrogen peroxide solution pump 2a. Further, a predetermined amount of the mixed solution is supplied from the mixed solution tank 5 to the mixer 6 via the mixed solution pump 5a. Thereby, the mixing ratio of the hydrogen peroxide solution supplied to the mixer 6 and the mixed solution is easily adjusted. For this reason, the shade of the color after bleaching can be appropriately adjusted according to the tree species. For example, by increasing the blending ratio of the hydrogen peroxide solution, the color of the surface of the material can be harmonized, and discoloration due to mold, decaying fungi, etc. can be effectively bleached.

  In this embodiment, soft water is used as the dilution water for the bleaching solution. This soft water does not contain much calcium ions or magnesium ions that bind to carbon dioxide or the like in water and precipitates scales, and contains a large amount of sodium ions that do not easily precipitate scales. For this reason, clogging in piping and the spray nozzle 13b mentioned later is suppressed compared with tap water and groundwater with high hardness.

  Finally, the hydrogen peroxide solution and the mixed solution supplied to the mixer 6 are uniformly mixed by flowing in the pipe along the spiral shape. For this reason, the bleaching liquid formed by mixing hydrogen peroxide water with the liquid mixture of sodium metasilicate aqueous solution and soft water is stably manufactured with a desired compounding ratio. The produced bleaching solution is stored in the bleaching solution tank 7 and provided to the bleaching plywood production system 10 described later.

According to the bleaching solution manufacturing system 1 of the present embodiment as described above, the following effects can be obtained.
1. The blending ratio can be easily adjusted automatically according to the tree species and material color.
2. It is possible to adjust the hue when bleaching dark colors of wood and discoloration caused by mold, decaying fungi, etc.
3. By using soft water, it is possible to suppress the precipitation of scale in the piping and the spray nozzle 13b, which will be described later, and to prevent clogging.
4). A bleaching solution uniformly mixed at a desired blending ratio can be stably produced.

  Next, as shown in FIG. 2, the bleaching plywood manufacturing system 10 of the present embodiment mainly includes an adhesive applicator 11 that applies an adhesive to the base plate, and a hot press that heat-presses the single plate to the base plate. A bleaching solution coating machine 13 for applying a bleaching solution to the veneer, a bleaching drying conveyor 14 for bleaching and drying the plywood coated with the bleaching solution, and a bleaching solution for supplying the bleaching solution to the bleaching solution coating machine 13 And a supply device 15. Each configuration will be described below.

  The adhesive applicator 11 is for applying a certain amount of adhesive to a veneer serving as a surface material of a plywood. In this embodiment, as shown in FIG. 2, the adhesive applicator 11 includes an adhesive application roller 11a for applying an adhesive to the surface of a base plate serving as a base, and an application amount by the adhesive application roller 11a. A doctor roller 11b for adjusting the angle. And the doctor roller 11b adjusts the application quantity of an adhesive agent by increasing / decreasing the space | interval with the adhesive application roller 11a.

  The hot press machine 12 forms a plywood by thermocompression bonding of two plate materials coated with an adhesive. In the present embodiment, a single plate to be bleached is placed on a base plate coated with an adhesive, and then heated while being pressurized with a hot press machine 12. As a result, the adhesive is cured and bonded to each other, so that it is formed as a plywood.

  The bleaching liquid applicator 13 applies the bleaching liquid to the surface of the plywood where the remaining heat of the hot press machine 12 remains. In this embodiment, as shown in FIG. 2, the bleaching solution coating machine 13 is provided immediately after the hot press machine 12, and a bleaching solution coating roller 13a for coating the surface of the plywood with the bleaching solution, and this bleaching solution. The application roller 13a has a spray nozzle 13b for spraying the bleaching solution. The bleaching solution application roller 13a is constituted by a sponge roll so that the bleaching solution is uniformly applied to the wood. Moreover, the spray nozzle 13b is comprised by the nozzle which can be sprayed in fan shape, and about four pieces are provided in 1 m range in the axial direction of the bleaching liquid application roller 13a.

  The bleach-drying conveyor 14 bleaches and dries the plywood coated with the bleaching solution. In this embodiment, as shown in FIG. 2, the bleach-drying conveyor 14 has an endless belt 14a that is rotationally driven, and a plurality of supports 14b provided on the surface of the endless belt 14a. Each support 14b supports the plywood coated with the bleaching solution at an angle, and is formed in a skewer shape so that the contact area with the plywood becomes small. Moreover, each support body 14b is provided in the conveyance direction at intervals larger than the thickness of the plywood, so that each plywood can be easily dried. Further, the length and driving speed of the endless belt 14a are set so as to ensure a sufficient time (eg, 1 minute or more) to ensure bleaching with the bleaching solution and drying of the bleaching solution.

  The bleaching solution supply device 15 supplies the bleaching solution to the bleaching solution applicator 13. In this embodiment, as shown in FIG. 2, the bleaching liquid supply device 15 is configured to supply the bleaching liquid tank 7 that supplies the bleaching liquid to the spray nozzle 13b, the compressor 15a that supplies compressed air, and the compressed air from the compressor 15a. An electromagnetic valve 15b for supplying air into the bleaching solution tank 7, an electromagnetic valve 15c for exhausting compressed air in the bleaching solution tank 7, and a pressure regulator 15d for adjusting the pressure in the bleaching solution tank 7; And a strainer 15e for filtering dust and the like in the bleaching solution.

  As shown in FIG. 2, the bleaching tank 7 is provided with a liquid level sensor 15f, which is adjusted to an amount necessary for one cycle of processing (for example, 5 to 10 liters). Further, when the bleaching solution tank 7 is replenished with the bleaching solution, the above-described bleaching solution is closed by closing the air supply solenoid valve 15b and opening the exhaust solenoid valve 15c to release the compressed air in the bleaching solution tank 7. Each liquid is rapidly supplied from the hydrogen peroxide pump 2a and the mixed liquid pump 5a in the manufacturing system 1.

  Below, the effect | action at the time of manufacturing a bleaching plywood using the bleaching plywood manufacturing system 10 of this embodiment mentioned above is demonstrated.

  First, an adhesive is applied to the surface of the base plate by the adhesive applicator 11, and then a single plate is placed on the surface of the base plate and heat-pressed by the hot press machine 12. Thereby, the hardening | curing agent contained in an adhesive agent thermosets, a base plate and a single board are adhere | attached, and a plywood is formed.

  On the other hand, in the bleaching solution supply device 15, the pressure regulator 15d controls the supply solenoid valve 15b and the exhaust solenoid valve 15c, and the bleaching solution tank 7 has a predetermined pressure (eg, 0.15 to 0.4 hectopascal). ) To adjust. As a result, the amount of the bleaching solution supplied to the spray nozzle 13b and the amount of the bleaching solution sprayed from the spray nozzle 13b are adjusted. Further, since the strainer 15e filters and removes dust and the like in the bleaching solution, the spray nozzle 13b is prevented from being clogged.

  Further, when the liquid level sensor 15f detects the shortage of the bleaching solution in the bleaching solution tank 7, the air supply electromagnetic valve 15b is instantaneously closed in accordance with the stop or termination of the plywood supplied from the hot press machine 12. At the same time, the exhaust solenoid valve 15c is opened. Thereby, since the compressed air in the bleaching solution tank 7 is released, each solution is quickly supplied from the hydrogen peroxide pump 2a and the mixed solution pump 5a in the bleaching solution production system 1 and replenished as a bleaching solution.

  With the above configuration, the bleaching solution in the bleaching solution tank 7 is always kept at the minimum necessary amount, so that the change with time of the hydrogen peroxide solution and sodium metasilicate is suppressed to the minimum. Further, it is not necessary to wash with water after the processing is completed, and the bleaching solution remaining in the bleaching solution tank 7 can be used to wet the bleaching solution application roller 13a when the next processing is started. In addition, since the bleaching solution sprayed after the plywood to be processed is stopped at the time of replenishment or at the time of replenishment, a valve for stopping the bleaching solution between the bleaching solution tank 7 and the spray nozzle 13b is provided. do not need.

  Next, in the bleaching liquid coating machine 13, the spray nozzle 13b sprays the pressurized bleaching liquid vigorously onto the bleaching liquid coating roller 13a. For this reason, since the bleaching solution is uniformly sprayed throughout the bleaching solution coating roller 13a, uneven coating on the wood is prevented. Further, since the pressurized bleaching solution is sprayed only on the bleaching solution application roller 13a and scattering to the surroundings is suppressed, a good working environment is maintained with less unpleasant smell.

  On the other hand, the plywood heat-pressed by the hot press machine 12 is supplied to the bleaching solution coating machine 13 with remaining heat remaining, and the bleaching solution is applied by the bleaching solution coating roller 13a. For this reason, the bleaching process is accelerated by the residual heat, and the bleaching solution is quickly dried.

  Subsequently, the plywood coated with the bleaching solution is sequentially supported by the support 14b of the bleach-drying conveyor 14, and is conveyed without being overlapped with other plywood for a predetermined time. For this reason, uneven bleaching hardly occurs in each plywood, and the bleaching solution is sufficiently dried while being bleached uniformly.

The bleaching plywood manufacturing system 10 of the present embodiment as described above has the following effects.
1. Ensuring sufficient time after applying the bleaching solution, effectively utilizing the residual heat of the hot press machine 12 to promote the bleaching action and sufficiently dry the bleaching solution.
2. 2. The plywood is uniformly bleached while leaving the grain of natural wood to reduce material color variation, and the quality as wall material and flooring material can be improved. By eliminating or relieving discoloration from the outside of the wood or color unevenness of the old wood, the yield of wood can be improved and wood can be used effectively.
4). The coating amount of the bleaching solution can be appropriately adjusted according to the type of plywood.
5. By always storing only the minimum necessary bleaching solution in the bleaching solution tank 7, it is possible to minimize the temporal change of the hydrogen peroxide solution and sodium metasilicate.
6). It is not necessary to wash the bleach solution tank 7 after the processing is completed, and the bleach solution remaining in the bleach solution tank 7 can be used to wet the bleach solution application roller 13a when starting the next process. .
7). Since the bleaching solution is not sprayed when the bleaching solution is replenished or after the plywood to be processed passes, it is not necessary to provide a valve for stopping the bleaching solution between the bleaching solution tank 7 and the spray nozzle 13b.

  As described above, the bleached plywood according to the present invention is bleached with a bleaching solution in which a mixed solution of a sodium metasilicate aqueous solution and soft water is mixed with a hydrogen peroxide solution. Moreover, the bleaching liquid of this embodiment is manufactured by the above-described bleaching liquid manufacturing system 1 at a blending ratio particularly suitable for wood bleaching. Hereinafter, the said mixture ratio is demonstrated concretely.

  The blending ratio of the hydrogen peroxide solution as the main component of the bleaching solution is 20 to 25% by mass. By setting the blending ratio to 20% by mass or more, the minimum bleaching action for wood is ensured. On the other hand, when the blending ratio is 25% by mass or less, the bleaching action is exerted also on discoloration caused by dark wood, mold, decaying fungi, or the like while suppressing cost. In the present embodiment, the hydrogen peroxide solution is a solution of 35% hydrogen peroxide.

  Moreover, the compounding ratio of sodium metasilicate aqueous solution is 10-15 mass%. By setting the blending ratio to 10% by mass or more, the promoting action of the bleaching treatment is secured and the wood is prevented from becoming yellow. On the other hand, by setting the blending ratio to 15% by mass or less, it is possible to perform bleaching that emphasizes the grain while suppressing the cost. In the present embodiment, the sodium metasilicate aqueous solution is an aqueous solution of 5 to 30% sodium metasilicate and 1 to 5% sodium hydroxide. The sodium metasilicate may be in powder form.

  Furthermore, the mixing ratio of soft water is 60 to 70% by mass. By making this compounding ratio 60 mass% or more, the cost of the bleaching solution is reduced. On the other hand, the minimum bleaching effect | action can be ensured because a mixture ratio shall be 70 mass% or less.

  In addition, the bleaching plywood manufacturing system 10, the bleaching liquid manufacturing system 1, and the bleaching plywood according to the present invention are not limited to the above-described embodiments, and can be appropriately changed.

  For example, in the present embodiment described above, a metering pump is used as the hydrogen peroxide pump 2a and the mixed liquid pump 5a, but is not limited to this configuration. Other pumps may be used.

DESCRIPTION OF SYMBOLS 1 Bleaching liquid production system 2 Hydrogen peroxide water tank 2a Hydrogen peroxide water pump 3 Sodium metasilicate tank 3a Sodium metasilicate valve 4 Soft water tank 4a Soft water valve 5 Mixed liquid tank 5a Mixed liquid pump 6 Mixer 7 Bleach liquid tank 10 Bleaching Plywood manufacturing system 11 Adhesive application machine 11a Adhesive application roller 11b Doctor roller 12 Hot press machine
DESCRIPTION OF SYMBOLS 13 Bleaching liquid application machine 13a Bleaching liquid application roller 13b Spray nozzle 14 Bleaching drying conveyor 14a Endless belt 14b Support body 15 Bleaching liquid supply apparatus 15a Compressor 15b Solenoid valve 15c Exhaust solenoid valve 15d Pressure regulator 15e Strainer 15f Liquid surface sensor

Claims (8)

A hot press machine for forming a plywood by thermocompression bonding of two plate materials coated with an adhesive;
A bleaching solution coating machine for applying a bleaching solution to the surface of the plywood where the residual heat of the hot press machine remains,
A plurality of supports that support the plywood coated with the bleaching solution at an angle are provided on the surface of the endless belt that is rotationally driven at intervals larger than the thickness of the plywood along the conveying direction. With bleach drying conveyor,
Having bleached plywood manufacturing system.   The said bleaching liquid coating machine has a bleaching liquid application roller which apply | coats a bleaching liquid to the surface of the said plywood, and a spray nozzle which sprays the said bleaching liquid on the said bleaching liquid application roller. Bleached plywood manufacturing system. The bleaching plywood manufacturing system has a bleaching solution supply device that supplies the bleaching solution to the bleaching solution coating machine.
A bleach solution tank for supplying the bleach solution to the spray nozzle;
An air supply solenoid valve for supplying compressed air from a compressor into the bleaching solution tank;
An exhaust solenoid valve for exhausting the compressed air in the bleaching solution tank;
The system for producing bleached plywood according to claim 2, comprising: A hydrogen peroxide tank for storing hydrogen peroxide,
A sodium metasilicate tank storing a sodium metasilicate aqueous solution;
A soft water tank for storing soft water;
A mixed liquid tank for storing a mixed liquid of the sodium metasilicate aqueous solution and the soft water;
A mixer for mixing the hydrogen peroxide solution and the mixed solution;
A bleach solution tank for storing the bleach solution mixed in the mixer;
A bleaching liquid manufacturing system. A sodium metasilicate valve for measuring the sodium metasilicate aqueous solution supplied from the sodium metasilicate tank to the mixed liquid tank;
A soft water valve for measuring the soft water supplied from the soft water tank to the mixed liquid tank;
A hydrogen peroxide pump for supplying a predetermined amount of the hydrogen peroxide from the hydrogen peroxide tank;
A liquid mixture pump for supplying a predetermined amount of the liquid mixture from the liquid mixture tank;
The bleaching solution manufacturing system according to claim 4, comprising:   The bleaching-solution production system according to claim 4 or 5, wherein the mixer is configured by a pipe formed in a spiral shape.   Bleached plywood, bleached with a bleaching solution in which a mixed solution of sodium metasilicate aqueous solution and soft water is mixed with hydrogen peroxide. In the bleaching solution,
The mixing ratio of the sodium metasilicate aqueous solution is 10 to 15% by mass,
The blending ratio of the soft water is 60 to 70% by mass,
The bleaching plywood according to claim 7, wherein a blending ratio of the hydrogen peroxide solution is 20 to 25% by mass.

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