HK1161183A - Method of manufacturing compressed wood product - Google Patents

Description

Method for producing compressed wood product

Technical Field

The present invention relates to a method of producing a compressed wood article in which wood is compression-molded into a predetermined three-dimensional shape.

Background

In recent years, wood as a natural material has been attracting attention. Since wood has various wood grains, individual differences are generated according to the locations of drawing materials from the wood, which are the individualities of each product. In addition, scars and color changes caused by long-term use are unique styles, and may give a sense of touch to a user. For these reasons, wood has attracted attention as a raw material which is not found in products using synthetic resins or light metals and which can create personalized and interesting products, and the molding technology thereof has also made a dramatic progress.

As one of the molding techniques of the wood, there is a technique of compression molding the wood into a predetermined three-dimensional shape. For example, the following techniques are known: 1 piece of wood compressed in a softened state is temporarily fixed, and the wood is put into a mold and restored, thereby molding a wood having a three-dimensional shape (for example, refer to japanese patent application laid-open No. 11-77619). In this technique, the wood is first compressed in a state where the wood is softened, and temporarily fixed. Then, the board material formed by cutting the temporarily fixed wood is placed in a mold, and the board material is softened again in high-pressure steam to be subjected to bending treatment. Next, the curved material subjected to the bending process is again placed in the mold and softened, and is pressed by a press machine, thereby obtaining a final shape.

As another technique for compression molding of wood, the following techniques are known: in order to produce a wood material having higher dimensional stability by improving the Anti-swelling effect (ASE), the wood material is subjected to steam heating and pressurizing treatment, and then the heating and pressurizing treatment is performed as a secondary step (for example, see japanese patent No. 2855139). In this technique, as an example, it is described that dimensional stability of a flat plate-like wood is improved by subjecting the wood to heat and pressure treatment.

As an application example of the compression molding technique of wood, a technique is also known in which a decorative pattern that changes the wood grain can be easily formed (for example, see japanese patent application laid-open No. 2005-205618). In this technique, compression molding is performed as follows: a substantially bowl-shaped blank having a curved surface along the irregularities of the die surface of the molding die and having projections or recesses that protrude or recede from the curved surface to expose wood grains is taken out, and the projections or recesses are formed by compression molding to have smooth surfaces smoothly connecting the sides. According to the technique described in japanese patent application laid-open No. 2005-205618, it is possible to obtain various wood grain patterns having excellent appearance, which cannot be obtained by the conventional technique.

However, in the conventional technique described in japanese patent application laid-open No. 2005-205618, since the convex portions or concave portions provided locally are pressed and molded at the time of compression, a wood grain pattern which changes discontinuously appears on the surface of the compressed wood. As a result, the compressed wood grain pattern may give an unnatural impression.

Disclosure of Invention

The present invention has been made in view of the above circumstances, and an object thereof is to provide a method for producing a compressed wood article capable of producing a wood grain pattern in which wood grains naturally and continuously change and which has excellent appearance.

In the method of producing a compressed wood article according to an aspect of the present invention, a material constituting a shape of: the blank is softened by compressing the softened blank in a volume having a portion of a volume which decreases due to compression, and is deformed into a substantially bowl shape by compressing the softened blank in a water vapor atmosphere having a higher temperature and a higher pressure than the atmospheric temperature.

The above-described and other features, advantages and technical and industrial significance of this invention will be more fully appreciated upon reading the following detailed description of the invention in connection with the accompanying drawings.

Drawings

Fig. 1 is a flowchart showing an outline of a compressed wood article production method according to an embodiment of the invention.

Fig. 2 is a diagram schematically showing an outline of a blank forming process of the compressed wood article manufacturing method according to the embodiment of the invention.

Fig. 3 is a sectional view (sectional view taken along line a-a of fig. 2) showing the structure of the blank.

Fig. 4 is a diagram schematically showing the outline of the compression process in the compressed wood article production method according to the embodiment of the invention.

Fig. 5 is a sectional view taken along line a-a of fig. 4.

Fig. 6 is a diagram showing a state in which the deformation of the blank material has been substantially completed in the compression step of the compressed wood article production method according to the embodiment of the invention.

Fig. 7 is a diagram schematically showing the outline of the heating and shaping step of the compressed wood article manufacturing method according to the embodiment of the invention.

Fig. 8 is a view schematically showing a state in which a pair of a female die for heat shaping and a male die for heat shaping are clamped in the heat shaping step in the method for producing a compressed wood article according to the embodiment of the present invention.

Fig. 9 is a perspective view showing the structure of a blank after the heat shaping step in the method of producing a compressed wood article according to the embodiment of the invention.

Fig. 10 is a perspective view showing a structure of a digital camera exterior package, which is an application example of a compressed wood article manufactured by the compressed wood article manufacturing method according to the embodiment of the present invention.

Fig. 11 is a perspective view showing an external configuration of a digital camera externally mounted with the external packaging body shown in fig. 10.

Detailed Description

Hereinafter, a mode for carrying out the present invention (hereinafter, referred to as "embodiment") will be described with reference to the drawings. In addition, the drawings referred to in the following description are schematic views, and when the same object is shown in different drawings, the size, scale, and the like may be different.

Fig. 1 is a flowchart showing an outline of the processing of the method of producing a compressed wood article according to the embodiment of the invention. First, a blank material having a shape described later is taken out of a wood material to form a blank material (step S1). Fig. 2 is a diagram schematically illustrating an outline of the blank forming process. In the blank forming process, the blank 2 is taken out from the wood 1 such as a cleaning material in a non-compressed state by cutting or the like.

Fig. 3 is a sectional view of the blank 2 shown in fig. 2 taken along line a-a. In the blank 2, the peripheral edge portion that surrounds the closure passes through a plane P (1 st plane), and of the two spaces divided by the plane P, only one space is present(in the space above the plane P in FIG. 3) has a convex shape with a plurality of apexes T₁、T₂The undulation of (2). The blank 2 passes through the apex T₁、T₂And a vertex T with a high height from the plane P when viewed on the 2 nd plane (on the paper of FIG. 3) perpendicular to the plane P₁(height h)₁) Comparatively lower height h₂Vertex T of₂Rather, it is closer to the central axis O in the height direction perpendicular to the plane P. Specifically, in FIG. 3, the vertex T is₁Distance r from the central axis O₁Less than vertex T₂Distance r from the central axis O₂(r₁＜r₂). The blank 2 thus formed has a substantially uniform thickness and has a volume increased by the volume amount decreased by the compression step described later, so that the natural and continuously changing wood grains G are exposed on the surface (see fig. 10). The shape of the blank 2 is preferably set in consideration of various factors such as the size and the change in shape due to the production.

More generally, the blank formed in the blank forming step of the method of producing a compressed wood article according to the present embodiment may satisfy the following properties. That is, the billet formed in the billet forming step may be formed into the following shape: the blank has a peripheral edge portion which is closed around the blank, and has a relief including a plurality of convex vertexes in one space among 2 spaces divided by a 1 st plane, and regarding any two vertexes of the plurality of convex vertexes, a vertex having a height higher than the 1 st plane is located in the vicinity of a central portion when viewed on a 2 nd plane which passes through the two vertexes and is perpendicular to the 1 st plane, and the blank has a substantially uniform thickness. Therefore, for example, the number of convex peaks of the blank may be 3 or more.

Next, the material 2 is placed in a high-temperature and high-pressure water vapor atmosphere for a predetermined time to soften the material 2 (step S2). In the steam atmosphere, the pressure is about 0.1 to 0.8MPa and the temperature is about 100 to 170 ℃. Such a water vapor atmosphere is achieved by using a pressure vessel. In case a pressure vessel is used, the blank 2 may be softened by placing it in a pressure vessel with said water vapour atmosphere. Instead of softening the blank 2 in a high-temperature and high-pressure water vapor atmosphere, the blank 2 may be softened by heating the blank 2 with microwaves after absorbing moisture. Alternatively, the material 2 may be boiled and softened.

Then, the softened billet 2 is compressed (step S3). In this step, the blank 2 is deformed into a predetermined three-dimensional shape by sandwiching the blank 2 between a pair of dies in the same water vapor atmosphere as in the softening step and applying a compressive force. In the case where the blank 2 is softened in the pressure vessel, the blank 2 may continue to be compressed in the pressure vessel.

Fig. 4 is a diagram showing an outline of the compression process and showing a main structure of a mold used in the compression process. Fig. 5 is a sectional view taken along line a-a of fig. 4. As shown in fig. 4 and 5, the blank 2 is sandwiched between a pair of die 101 and punch 102, and a predetermined compression force is applied.

The die 101 that applies a compressive force from above the billet 2 in the compression step includes a concave portion 111, and the concave portion 111 has a smooth surface that abuts against the outer side surface of the billet 2 that protrudes. On the other hand, the punch 102 that applies a compressive force from below the blank 2 in the compression step includes a convex portion 121, and the convex portion 121 has a smooth surface that abuts against the recessed inner side surface of the blank 2. The lower end surface of the die 101 located on the outer periphery of the concave portion 111 and the upper end surface of the punch 102 located on the outer periphery of the convex portion 121 constitute a plane. In a state where the die 101 and the punch 102 are clamped, the lower end surface of the concave portion 111 overlaps the upper end surface of the convex portion 121. In this clamped state, the shape of the gap formed between the concave portion 111 and the convex portion 121 corresponds to the shape of the material 2 after the compression step.

The slope of the inner inclined surface of the concave portion 111 with respect to the lower end surface of the die 101 is larger than the slope of the vicinity of the peripheral edge portion of the blank 2 with respect to the plane P. Similarly, the slope of the outer inclined surface of the convex portion 121 with respect to the upper end surface of the punch 102 is larger than the slope of the vicinity of the peripheral edge portion of the blank 2 with respect to the plane P. As described above, in the present embodiment, the blank 2 before compression has a shape different from the shape of the compression-molding die.

In the compressionIn the step, the blank 2 is placed on the convex portion 121 and is brought into contact with the concave portion 111 from above. At this time, the blank 2 has a high apex (apex T) as viewed from a plane P through which the peripheral edge passes₁) Is located in the vicinity of the center portion, and therefore abuts against the concave portion 111 in order from the highest apex. Therefore, the blank 2 does not collapse from the convex portion 121 in the process of bringing the die 101 close to the punch 102. As a result, even if the blank 2 having a shape significantly different from the shape of the concave portion 111 and the convex portion 121 is used, it can be reliably compressed.

Fig. 6 is a diagram showing a state where the blank 2 is sandwiched between the die 101 and the punch 102 and a predetermined pressure is applied in the compression step, and shows a state where the deformation of the blank 2 is substantially completed. In the state shown in fig. 6, the billet 2 is deformed into a predetermined three-dimensional shape by receiving a compressive force from the die 101 and the punch 102. The predetermined three-dimensional shape described here is a shape corresponding to a gap formed by the concave portion 111 and the convex portion 121 in a state where the die 101 and the punch 102 are closest to each other. The three-dimensional shape is substantially similar to a final shape obtained through a heat shaping step (step S6) described later, and has a volume larger than the final shape.

However, in fig. 6, a plane Q where the lower end surface of the die 101 and the upper end surface of the punch 102 overlap each other passes through the peripheral edge portion of the substantially bowl-shaped blank 2. This means that plane Q is the same plane as plane P as plane 1. The slope of the vicinity of the peripheral edge of the blank 2 after the compression step with respect to the plane Q is larger than the slope of the vicinity of the peripheral edge of the blank 2 before the compression step with respect to the plane P. In other words, the maximum value of the inclination angle with respect to the plane Q in the vicinity of the peripheral portion of the blank 2 after the compression step is larger than the maximum value of the inclination angle with respect to the plane P in the vicinity of the peripheral portion of the blank 2 before the compression step. As described above, in the present embodiment, since the shapes of the blank 2 before and after compression are significantly different, a continuously changing wood grain pattern is easily obtained.

After the compression step is completed, the shape of the material 2 is fixed by forming a water vapor atmosphere having a higher temperature and a higher pressure than the water vapor atmosphere around the die 101 and the punch 102 in a state where the material 2 is held in a predetermined three-dimensional shape by the die 101 and the punch 102 being sandwiched therebetween (step S4). In this case, the pressure is about 0.7 to 3.4MPa and the temperature is about 160 to 240 ℃ in the steam atmosphere. When the immobilization treatment is performed in a pressure vessel, the pressure in the vessel in the softening step may be set to a value within the above range.

Next, the female die 101, the male die 102, and the billet 2 are opened to the atmosphere to dry the billet 2 (step S5). At this time, the drying of the blank 2 can be promoted by separating the female die 101 and the male die 102.

The thickness of the blank 2 after the drying step is preferably about 20 to 50% of the thickness of the blank 2 before the compression step. Here, there may be some deviation in the thickness of the blank 2. Therefore, in the present embodiment, the minimum value of the thickness of the material 2 is preferably set to be equal to or larger than the thickness of the final shape formed by the heating and shaping step described later.

After the drying process, the material 2 is heated in the atmosphere and shaped into a final shape (step S6). Fig. 7 is a view schematically showing the outline of the heating and shaping step. In the heat shaping step, the blank 2 is clamped by the pair of heat shaping dies 201 and the heat shaping punch 202, and the blank 2 is shaped into a final shape while being heated. Fig. 8 is a view schematically showing a state in which a pair of a female die for heat shaping and a male die for heat shaping are clamped in a heat shaping process.

The die 201 for shaping by heating located above the billet 2 in fig. 7 is provided with a concave portion 211, and the concave portion 211 has a smooth surface abutting against the surface of the billet 2 on the projecting side. On the other hand, the convex portion 221 is provided in the convex die 202 for heat shaping located below the blank 2 in fig. 7, and the convex portion 221 has a smooth surface abutting against the surface on the recessed side of the blank 2. The lower end surface of the heat shaping die 201 located on the outer periphery of the concave portion 211 and the upper end surface of the heat shaping punch 202 located on the outer periphery of the convex portion 221 are flat surfaces. As shown in fig. 8, in a state where the heating and shaping die 201 and the heating and shaping punch 202 are clamped, the lower end surface of the concave portion 211 overlaps the upper end surface of the convex portion 221. In this clamped state, the shape of the gap formed between the concave portion 211 and the convex portion 221 corresponds to the final shape of the blank 2, i.e., is substantially bowl-shaped. The volume of the final shape of the substantially bowl shape is smaller than the volume of the material 2 after the compression step by a portion reduced by the heat shaping step.

Heating bodies 203 and 204 that generate heat are provided inside the heating and shaping die 201 and the heating and shaping punch 202, respectively. The heating bodies 203 and 204 are connected to a controller 205 having a temperature control function, and heat is generated by the controller 205 to heat the heating and shaping die 201 and the heating and shaping punch 202, respectively. The controller 205 controls the mold temperature at the time of clamping the material 2 to be not lower than the temperature at which the amorphous region of the xylem is crystallized and not higher than the thermal decomposition temperature of the xylem.

In this way, the controller 205 controls the mold temperature, and thereby the density of the wood part is further increased while the crystallization of the wood part progresses in the process of the heating and shaping step, and the surface hardness of the wood part is increased. As a result, a compressed wood article having no moisture absorption and good shape stability can be obtained.

Further, the surface of the blank 2 is heated and shaped in the air, whereby substances contained in the interior of the cell walls of the xylem are extracted to the surface, and color and luster are produced on the surface. As a result, the unique style of the wood itself can be exhibited.

Further, if the shaping body is provided on the outer surface of the blank 2 facing the concave portion 211, the tensile force acting on the outer surface of the blank 2 can be suppressed as much as possible at the time of heat shaping. Therefore, cracks and the like on the surface of the material 2 during the heat shaping can be more reliably prevented.

Fig. 9 is a perspective view showing the structure of a blank (hereinafter, referred to as "compressed wood article 3") obtained by performing a heat-shaping process. The compressed wood article 3 shown in the figure includes: a flat plate-like main plate portion 3a having a substantially rectangular surface; two side plate portions 3b bent and extended from two long side portions opposed to each other on the surface of the main plate portion 3a with respect to the main plate portion 3 a; and two side plate portions 3c bent and extended from two short side portions opposed to each other on the surface of the main plate portion 3a with respect to the main plate portion 3 a.

Fig. 10 is a perspective view showing an exterior package structure of a digital camera, which is an application example of a compressed wood article produced by the compressed wood article production method described above. The exterior body 4 shown in the figure exteriorly covers the front side (the side opposite to the subject) of the digital camera, and has a main plate portion 4a and side plate portions 4b and 4c corresponding to the main plate portion 3a and the side plate portions 3b and 3c of the compressed wood product 3, respectively. The main plate portion 4a has a cylindrical opening 41 for exposing an imaging portion of the digital camera and a rectangular parallelepiped opening 42 for exposing a flash of the digital camera. The side plate 4b has a semi-cylindrical notch 43 exposing the shutter button.

Fig. 11 is a perspective view showing an external configuration of a digital camera in which the front side is externally mounted by the external body 4. The digital camera 301 shown in the figure has: an image pickup section 302, a flash 303, and a shutter button 304. The front side of the digital camera 301, on which the imaging unit 302 and the flash 303 are exposed, is externally covered by the exterior body 4. On the other hand, the back side of the digital camera 301 is externally covered with an exterior body 5, and the exterior body 5 is formed by using the compressed wood product 3 in the same manner as the exterior body 4. In this way, when the compressed wood article produced by the compressed wood article production method of the present embodiment is applied as an exterior package of a digital camera, the thickness is preferably about 1.6 to 2.0 mm.

According to the above-described embodiment of the present invention, since the blank is formed in a shape in which the peripheral edge portion closed around the blank passes through the 1 st plane, and the blank is compressed, a wood grain pattern in which the wood grain changes naturally and continuously can be produced, the blank has a shape in which the relief including the plurality of convex vertexes is provided only in one of two spaces separated by the 1 st plane, and with respect to any two vertexes among the plurality of convex vertexes, when viewed on the 2 nd plane passing through the two vertexes and perpendicular to the 1 st plane, the vertex having a high height from the 1 st plane is located in the vicinity of the central portion, and the blank has a volume in which the volume of the portion reduced by the compression is increased.

Further, the compressed wood article produced by the method of producing a compressed wood article of the present invention can also be used as an exterior body for electronic equipment other than a digital camera. The compressed wood article produced by the method of producing a compressed wood article of the present invention can be applied to tableware, various housings, building materials, and the like, for example.

According to the present invention, since the blank having a shape in which the peripheral edge portion closed is passed through the 1 st plane, of the two spaces divided by the 1 st plane, the blank has a relief including a plurality of convex apexes only in one space, and regarding any two apexes among the plurality of convex apexes, the apex having a high height from the 1 st plane is located in the vicinity of the central portion as viewed on the 2 nd plane passed through the two apexes and perpendicular to the 1 st plane, and the blank has a volume increased by a portion of the volume decreased by compression, and is compressed, a wood grain pattern in which the wood grain naturally and continuously changes can be produced.

Further effects or variants can easily be derived by the person skilled in the art. Thus, the broader aspects of the invention are not limited to the specific, detailed, and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.

Claims (6)

1. A method of producing a compressed wood article having a three-dimensional shape including a curved surface by compressing wood, wherein the production method comprises the steps of:

taking out from the wood a blank constituting the following shape: passing a 1 st plane around a closed peripheral portion, having a relief including a plurality of convex vertexes in only one space among two spaces divided by the 1 st plane, and regarding any two vertexes of the plurality of convex vertexes, a vertex having a high height from the 1 st plane is located in the vicinity of a central portion and has a volume increasing a portion of a volume decreased by compression when viewed on a 2 nd plane passing through the two vertexes and perpendicular to the 1 st plane,

so that the blank is softened and then the blank is put into a mold,

the softened material is compressed in a steam atmosphere at a higher temperature and a higher pressure than the atmosphere, and is deformed into a substantially bowl shape.

2. The method of producing a compressed wood article according to claim 1, wherein,

the slope of the vicinity of the peripheral edge of the compressed material with respect to the 1 st plane is larger than the slope of the vicinity of the peripheral edge of the compressed material with respect to the 1 st plane.

3. The method of producing a compressed wood article according to claim 2, wherein,

in the compression, a pair of dies is used to clamp the blank and apply a compressive force.

4. The method for producing a compressed wood article according to claim 3,

further comprising the steps of: and a step of holding the compressed billet in a state of being sandwiched between the pair of dies, and placing the compressed billet in a water vapor atmosphere having a higher temperature and a higher pressure than the water vapor atmosphere, thereby fixing the shape of the compressed billet.

5. The method of producing a compressed wood article according to claim 1, wherein,

in the compression, a pair of dies is used to clamp the blank and apply a compressive force.

6. The method of producing a compressed wood article according to claim 5, wherein,

further comprising the steps of: and a step of holding the compressed billet in a state of being sandwiched between the pair of dies, and placing the compressed billet in a water vapor atmosphere having a higher temperature and a higher pressure than the water vapor atmosphere, thereby fixing the shape of the compressed billet.