Heat compression molding method for wood flour

Abstract

To provide a heat compression molding method that performs the heat compression molding of wood at low cost.SOLUTION: A heat compression metallic molding method for wood flour includes a filling step of filling a metallic mold enabling heating, pressurizing, and holding under reduced pressure with respect to the filled material, a pre-pressurization step of pressurizing the material in the metallic mold with raw material at 12.8 MPa to 179.5 MPa after the filling step, a reduced pressure step of holding the material in a reduced pressure state at 12.8 MPa to 38.5 MPa in the filled metallic mold after the pre-pressurization process, a heating step of heating the filled metallic mold after the reduced pressure step, and a main pressurization step of pressurizing the material in the filled metallic mold at 12.8 MPa to 179.5 MPa after the heating step, followed by a demolding step of performing demolding after the main pressurization step.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a method for hot compression molding of wood flour. [Background technology]

[0002] In recent years, techniques for compression molding not only sawdust but also wood have been widely studied. For example, as a method for molding wood, there is a method in which wood is steam-treated to make it easier to mold, and then deformation and fixing are performed. More specifically, there is a method in which wood is steam-treated in advance, and a method in which wood is steam-treated in a state where it is filled in a mold structure.

[0003] Patent Document 1 describes a method for producing a molding material with any three-dimensional shape by finely crushing wood-based material to produce a fine powder, treating it with steam to soften it and make it fluid, and pouring it into a mold and hot pressing it, or by placing the fine powder in a mold, pressing it while treating it with steam, molding it, and then cooling and solidifying it. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2001-203247 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, when steam treating wood, it is necessary to prepare a steam treatment facility separately from the pressing facility, which increases the investment and running costs.

[0006] The present disclosure provides a method for thermal compression molding of wood at low cost. [Means for solving the problem]

[0007] The method for thermal compression molding of wood flour according to the present disclosure includes a filling step of filling a material into a mold capable of heating, pressurizing, and maintaining a reduced pressure on the filled material, a pre-pressurizing step of pressurizing the material in the mold filled with the material at 12.8 MPa to 179.5 MPa after the filling step, a depressurizing step of reducing the pressure after the pre-pressurizing step and maintaining the material in a reduced pressure state at 12.8 MPa to 38.5 MPa in the mold filled with the material, a heating step of heating the mold filled with the material after the depressurizing step, a main pressurizing step of pressurizing the mold filled with the material at 12.8 MPa to 179.5 MPa after the heating step, and a demolding step of releasing the material after the main pressurizing step. This allows the pre-processing to be carried out by utilizing the moisture contained in the wood itself. Effect of the Invention

[0008] According to the present disclosure, a thermal compression molding method for performing thermal compression molding of wood at low cost can be provided. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a block diagram showing a configuration of a thermal compression molding system. [Diagram 2] FIG. 2 is a diagram showing an operation flow of the thermal compression molding system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] First embodiment Hereinafter, a thermal compression molding system according to the present embodiment will be described with reference to the drawings. Fig. 1 is a diagram showing an example of the configuration of a thermal compression molding system 1. In the thermal compression molding system 1, thermal compression molding of a material is performed. Here, the material is wood, specifically wood powder or sawdust, but is not limited to these.

[0011] The thermal compression molding system 1 includes a material filling means 11 , a pre-pressurizing means 12 , a reduced pressure maintaining means 13 , a heating means 14 , and a main pressurizing means 15 .

[0012] The material filling means 11 is a means for filling a material into a metal mold capable of being filled with the material inside. Here, the metal mold has a space into which the material is filled, and the filled material can be heated, pressurized, and decompressed.

[0013] The pre-pressurizing means 12 is a first pressurizing means for applying pressure to the material filled in the mold before applying pressure using the main pressurizing means 15 .

[0014] The reduced pressure maintaining means 13 is a means for maintaining a reduced pressure state for the material filled in the mold. For example, the reduced pressure maintaining means 13 reduces the pressure inside the mold using a device for reducing the pressure, and then maintains the mold so that the reduced pressure state inside the mold is maintained without using power.

[0015] The heating means 14 heats the mold that is held in a reduced pressure state by the reduced pressure holding means 13. As a result, the heating means 14 heats the material filled in the mold.

[0016] The main pressurizing means 15 is a second pressurizing means for applying pressure to the material filled in the mold. The main pressurizing means 15 can be the same means as the pre-pressurizing means 12. That is, the thermal compression molding system 1 can be provided with only one pressurizing means.

[0017] Next, a detailed description will be given of a molding method using the thermal compression molding system 1. Figure 2 is a diagram showing an example of the flow of the molding method.

[0018] First, the material filling means 11 fills the material into a mold capable of heating, pressurizing and decompressing (step S1). This process is referred to as a filling process.

[0019] The pre-pressurizing means 12 applies pre-pressurization to the inside of the mold (step S2). In other words, the pre-pressurizing means 12 applies pre-pressurization to the material filled inside the mold. This process is referred to as the pre-pressurizing process. The pressure applied to the material inside the mold by the operation of the pre-pressurizing means 12 is 12.8 MPa to 179.5 MPa.

[0020] Thereafter, the pre-pressurizing means 12 is stopped to release the pressure, thereby allowing the air trapped inside the material to be released.

[0021] The reduced pressure maintaining means 13 maintains the reduced pressure state inside the mold (step S3). In other words, the reduced pressure maintaining means 13 maintains a state in which the pressure applied to the material inside the mold is reduced. This process is referred to as a depressurization process. More specifically, the reduced pressure maintaining means 13 maintains the mold so that the pressure inside the mold is maintained in a reduced state compared to the pressure applied to the material by the pre-pressurization means 12. The pressure in the reduced pressure state maintained by the reduced pressure maintaining means 13 is 12.8 MPa to 38.5 MPa.

[0022] The heating means 14 heats the material together with the mold in a state in which low pressure is applied by the reduced pressure holding means 13 (step S4). This process is called a pressurizing process. Here, the heating means 14 heats the mold, so that moisture inside the material filled in the mold evaporates.

[0023] Here, the mold heated by the heating means 14 is in a state where moisture is difficult to escape to the outside because the inside of the mold is decompressed. Therefore, the material filled in the mold is in a state where it is steam-treated by the moisture of the material itself. Typically, the heating means 14 can heat the mold to a temperature between 180 and 315°C, but the bending strength of the molded body can be maximized by setting the mold temperature to around 270°C.

[0024] The main pressurizing means 15 applies a second pressurization to the inside of the mold after the heating means 14 stops heating. In other words, the main pressurizing means 15 applies main pressurization to the material inside the mold (step S5). This step is referred to as the main pressurizing step. The pressure applied to the material inside the mold by the operation of the main pressurizing means 15 is set to 12.8 MPa to 179.5 MPa, similar to step S2.

[0025] Thereafter, the thermal compression molded product formed in the mold is released and taken out (step S6). This step is referred to as a demolding step.

[0026] As an example, in the thermal compression molding system 1, the pre-pressurization pressure is set to 140 MPa, the depressurization pressure is set to 0 MPa, the heating pressure is set to 30 MPa, the heating temperature is set to 250°C, and the main pressurization pressure is set to 140 MPa, thereby making it possible to form a molded product that has been steam-treated, making use of the moisture contained in the wood material itself.

[0027] In this way, in the thermal compression molding system 1, steam treatment can be performed by utilizing the moisture contained in the wood itself, by heating the mold while the pressure inside is reduced by the reduced pressure holding means 13. That is, in the thermal compression molding system 1, by performing pre-processing by the first pressurization, it is possible to remove the air trapped inside the material and to perform the pre-pressurization process by utilizing the moisture contained in the wood material itself.

[0028] Therefore, with the thermal compression molding system 1, there is no need to prepare separate equipment just for steam treatment, which reduces capital investment costs and running costs, and also makes it possible to mold stronger wood molded products.

[0029] The present invention is not limited to the above-described embodiment, and can be modified as appropriate without departing from the spirit of the present invention. In other words, the above description has been omitted or simplified as appropriate for the purpose of clarity, and a person skilled in the art can easily modify, add, or convert each element of the embodiment within the scope of the present invention.

[0030] For example, the pressures and temperatures in the above-mentioned steps are merely examples and can be changed as appropriate.

[0031] For example, in the thermal compression molding system 1, a strong wooden molded product can be molded by setting the pre-pressurization and main pressurization at 100 MPa or more and setting the pressure in the depressurization process to a sufficiently low pressure.

[0032] In particular, in the thermal compression molding system 1, when the heating temperature in the heating step of step S4 is increased, the molded product becomes darker in color, becomes more glossy, and feels harder to the touch at higher temperatures. Also, since discoloration of the molded product is particularly severe when the heating temperature is between 200°C and 270°C, the heating temperature can be changed appropriately according to the application.

[0033] Also, for example, the pressure applied in pre-pressurization and main pressurization can be changed in the thermal compression molding system 1. For example, in the thermal compression molding system 1, it is possible to set the pressure applied in pre-pressurization to 15 MPa or 30 MPa, and to apply a pressure of up to 140 MPa in main pressurization without reducing the pressure in the depressurization process. In this case, the lower the pre-pressurization pressure, the more the original texture of the material remains in the molded product and discoloration is reduced, but unevenness becomes more noticeable.

[0034] Here, in the thermal compression molding system 1, pressure is generated when performing pre-pressurization and main pressurization, but since energy is required to generate this pressure, there is also a demand to perform molding at as low a pressure as possible.

[0035] Therefore, in the thermal compression molding system 1, it is possible to perform processing in which the pressure applied in the pre-compression is set to 12.8 MPa, a slight reduction in pressure is performed in the decompression process, and the pressure applied in the main compression is also set to 12.8 MPa. In this case, the thermal compression molding system 1 forms a molded product that feels soft to the touch.

[0036] In other words, in the thermal compression molding system 1, when the molded product can be made soft, the pressure applied when applying the pre-pressure and main pressure can be low, thereby making it possible to reduce energy costs. [Explanation of symbols]

[0037] 1. Thermocompression molding system 11 Material filling means 12 Pre-pressurizing means 13 Reduced pressure maintaining means 14 Heating means 15. Pressurizing means

Claims

[Claim 1] A filling step of filling a material into a mold capable of applying heat, pressure and vacuum to the filled material; A pre-pressurizing process of pressurizing the material at 12.8 MPa to 179.5 MPa in the mold filled with the material after the filling process; a decompression process in which the pressure is reduced after the pre-pressurization process, and the material is held in a decompressed state at 12.8 MPa to 38.5 MPa in the mold filled with the material; a heating step of heating the mold filled with the material after the decompression step; After the heating step, a main pressurizing step of pressurizing the mold filled with the material at 12.8 MPa to 179.5 MPa; A demolding process is performed after the main pressurizing process. A method for thermocompression molding of wood powder.

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