JP2000158421A - Molded product of intermediate density fiberboard with curved face and processing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a molded product of an intermediate density fiberboard with a curved face having a specific curvature radius and a method for processing the molded product. SOLUTION: An intermediate density fiberboard 1 cut to an appropriate shape is thermally treated for 10-30 min using an overheated steam at 110-120 deg.C and then is immediately loaded in the top force 2 and the bottom force 3 of a hot press mold with a curved face having a curvature radius 50-15 times the thickness of the board 1. Further the fiberboard 1 is gradually pressurized in the initial stage until la specified pressure is reached, under conditions such as 10-40 kg/cm2 pressure and 120-250 deg.C temperature, and then continues to be pressurized for some time but at an accelerated tempo and at the same time, is clamped to be molded. As soon as the fiberboard 1 is freed from the hot pressing process, it is exposed to cold air at 5 deg.C or less through a quenching step to obtain a finished product.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a medium-density fiberboard having a curved surface with a radius of curvature of 50 to 15 times the thickness of a board used in the fields of lacquer ware, furniture, civil engineering construction, automobile interior fittings, and other wood products. (Hereinafter abbreviated as MDF).

[0002]

2. Description of the Related Art Conventionally, a hard fiberboard (hardboard) having flexibility has been disclosed by Japanese Utility Model Application Laid-Open No. H5-155-1.
No. 0500 and Japanese Patent Publication No. 6-79807 (Japanese Patent Application Laid-Open No. 62-20764) relating to the dry manufacturing method, etc., each of which discloses a technique. Also, a curved surface using a medium fiberboard (synonymous with MDF) or particle board as a core material. As for molded wood boards,
It is disclosed in Japanese Patent Application Laid-Open No. 9-104008.

[0003] As is well known, wooden fiberboard is divided by the density, is of less than 0.35 g / cm ³ is referred to as a insulation board (IB), 0.35g / cm3~0.
8 g / cm ³ is referred to as MDF, and 0.8 g / cm ³ or more is referred to as a hard board (HB). In the present invention, a curved surface having a radius of curvature of 50 to 15 times the thickness of the plate is particularly preferred. The present invention relates to a product and a processing method thereof.

[0004] The invention of the "curved surface-formed wooden board" described in Japanese Patent Application Laid-Open No. 9-104008 discloses a core material formed of MDF having a curved surface, and affixed along an inner surface and an outer surface of the core material. And a decorative member adhered along each surface of the core material, and the core material is an inner periphery of the curved surface portion. It is characterized by being a laminate obtained by using a veneer having a groove portion having a V-shaped cross section in a portion corresponding to the surface.

[0005] The laminate is placed in a mold for hot pressing after appropriately interposing an adhesive such as phenol resin, urea, or melamine resin between the layers, and is heated and pressed to form a molded product. It was done.

[0006] The "flexible wood fiber board" according to the dry manufacturing method described in Japanese Patent Publication No. 6-79807 discloses a method in which a thermoplastic synthetic rubber latex is added to wood fibers during fibrillation of steamed wood chips. 3 to 10% by weight,
Thickness produced by accumulating wood fibers containing water of 6 to 10% obtained by flash drying in a mat form, flattening them with a flat plate pressing pressure of 50 to 80 kg / cm ² and a heating temperature of 120 to 180 ° C. for 4 minutes. According to an embodiment, the product has a maximum radius of curvature of 25.7 to 21.4 times the thickness of the board, and a phenol resin and a wax are used as comparative examples. The maximum radius of curvature of the fiberboard obtained by adding and processing according to the above-described example is described as 60 times the thickness of the fiberboard.
(See Table 1 of the same publication)

On the other hand, Japanese Utility Model Laid-Open No. 5-1050 relating to the wet process.
According to the "hard fiber board having flexibility" described in Japanese Patent Publication No. 0, the synthetic resin having flexibility, for example, a thermoplastic resin such as the synthetic rubber latex, is not used, and the weight is 1. 5% water repellent paraffin wax phenol resin and 0.6% parts by weight was added, and integrated in a mat shape on wire mesh in three steps (temperature about 200 ° C., for example at a pressure 40 kg / cm ² 1 1 minute 30 seconds at a pressure of 8 kg / cm ² for 1 minute
The fiberboard is manufactured by pressing with a heat and pressure method of 20 kg / cm ² at a pressure of 20 kg / cm ² for 1 minute and 30 seconds (4 minutes). In this case, the wire mesh used is a conventional wire diameter of 0.3 to 0.5 mm. The single wire plain weave system with a mesh size of 0.6 to 1.2 mm was improved to use a plain weave wire mesh with a wire diameter of 0.6 to 1.0 mm and a mesh size of 1.5 to 4.5 mm. . It is described that when the molding is performed at 200 ° C. by the three-stage hot-pressing method at a maximum pressure of 40 kg / cm ² , the amount of deflection is improved by about 1.555 to 5 times as compared with a conventional hard fiberboard.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a commercially available MDF single veneer, a veneer veneer, a paper veneer, a cloth veneer, an appropriate surface treatment such as polishing, coloring, painting and printing. Material for lacquerware base, furniture, civil engineering construction, automobile interior, etc., which has a curved surface with a radius of curvature of 50 to 15 times the thickness of the plate for a 2.5 to 30 mm thick MDF The purpose is to do.

[0009] Plastic products are currently heavily used for materials such as lacquerware base and furniture, but it is hard to say that these products give moisturization to our sense of touch such as so-called "warmth" and "warmth". In other words, those that are chemically synthesized or recycled as substitutes for the original wood products
It is hard to adapt to our lives. The wood fiberboard, which is symmetrical to the present invention, is much more suitable than plastic, and in order to make the most of limited terrestrial resources as effectively as possible, and to incinerate waste wood, Recycling waste wood into wooden boards is of great significance in terms of causing a great deal of pollution of the global environment. Furthermore, the MDF produced by the above-mentioned conventional technology is now widely available on the market as an MDF flat plate which is excellent in flexibility but does not cause deformation such as warpage and twisting, unevenness and poor adhesion.

[0010]

According to the present invention, there is provided a recording medium having a thickness of 2.5.
After cutting a processed plate such as an MDF single veneer or a wood-tipped plate having a thickness of up to 30 mm into a desired shape, steaming it once with superheated steam at 110 ° C. to 120 ° C., the desired curved surface (radius of curvature) Is 50 to 15 times the thickness of the plate).
Under a condition of ４０40 kg / cm ² and a temperature of 120 ° C. and 250 ° C., the mixture is slowly heated and pressed. Immediately after the pressing is released from the press machine, it is exposed to cold air of about 5 ° C. or lower to cool and finish as quickly as possible.

[0011] The MDF curved molded product according to the present invention has a considerably large curvature rate and must not cause deformation or crack breakage while maintaining its shape for a long period of time. Although not influenced by the structural directionality of the MDF, depending on whether the resin agent used in the production is a thermoplastic resin such as a synthetic rubber latex or a thermosetting phenol, urea, melamine resin, etc. It is necessary to select some processing conditions such as temperature and time. Furthermore, after the completion of the heating and pressing, the shape is securely fixed by exposing it to cold air of at least 5 ° C. or less and rapidly cooling to eliminate the possibility of warping, twisting, unevenness and other deformation during practical use. Successful.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an MD having a curved surface according to the present invention.
An F-shaped product and a processing method thereof will be described with reference to the drawings.

FIG. 1 is an explanatory view showing a state in which the MDF having a curved surface of the present invention is hot-pressed after steaming and heat-treating.
Fig. 1 illustrates a molded article according to the present invention, in which (a) is a furniture material, (b) is a confectionery tray, and (c) is a food dish, all of which are perspective views.

In the present invention, as shown in Japanese Patent Application Laid-Open No. 9-104008, which has been exemplified in the prior art, a V-shape is formed on the inner peripheral surface of the curved portion of the core material (corresponding to the MDF elementary plate of the present invention). Because there is no groove with a mold cross section, use superheated steam with low humidity and excellent permeability as the appropriate heating and pressing conditions for forming the curved surface, and quickly and evenly raise the temperature to the inside of the material veneer To increase plasticity.

As an MDF material generally used for forming a curved surface, a plate material having a thickness of 2.5 to 4 mm is generally used.
Thickness of about this or sticking board, polishing, painting,
If the surface is processed by coloring or the like, the desired temperature can be reached in about 10 minutes by using a superheated steam of 110 ° C. Further, depending on the resin material constituting the raw material, for example, if the material is thermoplastic, the object can be achieved at a temperature somewhat lower than that using a thermosetting resin and for a shorter time.

In any case, a symmetrical MDF cut into an appropriate shape is placed in the steaming chamber at an appropriate interval, and
After adding superheated steam of 10 ° C to 120 ° C and performing a steaming heat treatment for 10 to 30 minutes, it is immediately inserted into a hot press having a predetermined curved surface, and pressure is 10 to 40 kg / cm ² , temperature is 120 ° C.
Under the condition of ~ 250 ° C, the initial pressure is gradually increased gradually until the predetermined pressure is reached, press-molding is performed while increasing the pressure, and immediately after being released from the hot press, it is transferred to the cooling chamber, and the temperature is reduced to 5 ° C or more. Exposure to the following cool air and quench to finish. The steaming treatment with the superheated steam is useful for discharging the formalin remaining in the material of the MDF, and has an excellent effect that the surface of the molded product is not changed except for the color.

The processing method of applying the present invention to finish by applying a rapid cooling treatment with cold air after the pressing treatment after the steam heat treatment with the superheated steam is the most characteristic of the present invention, and the molded product thus produced. There is no fear of deformation unless special measures are taken. However, those that have been colored by coloring, printing, etc. may be discolored due to the properties of the dyes and pigments to be used. Therefore, it is necessary to investigate and take measures in advance.

[0018]

An embodiment of the present invention will be described with reference to the drawings. As described above, FIG. 1 is an explanatory diagram showing a state of hot pressing after steaming heat treatment, and FIG. 2 illustrates a molded product according to the present invention, wherein (a) is a household item and (b) is a confectionery. The tray and (c) are perspective views of the food dish. The press die shown in FIG. 1 is an example having a curved surface having a radius of curvature of about 25 times the plate thickness of 12 mm.

MDF material cut into a predetermined shape (1)
Is placed in a steaming chamber set at a predetermined temperature with an appropriate partition or net shelf, and then steaming heat treatment is performed by introducing superheated steam. The appropriate steaming temperature is 110 ° C to 120 ° C.
After heating for 5 to 10 minutes in consideration of the thickness of the DF, coloring agent, etc., immediately sandwich it between the male mold (2) and the female mold (3) for hot pressing set at 120 ° C to 250 ° C, At first, the pressure is gradually and gradually increased through the pressure plates (4) and (4a) to reach the desired pressure of 10 to 40 kg / cm ² ,
After further pressurizing for a minute, the mixture is introduced into a cooling chamber, and is cooled rapidly by injecting cold air of 5 ° C. or lower to obtain a molded product having a desired curved surface. If both of the above processing conditions can be applied, the conventional apparatus can be used, and the economical efficiency is almost the same as the conventional apparatus.

[0020]

According to the present invention, an MDF having excellent surface properties as a woody wood product replacing conventional pure wood products
However, it is possible to finish a shape having a curved surface with a radius of curvature of 50 to 15 times the thickness of the plate, and the economic effect as a daily necessity as well as the artistic effect is great.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a state of a hot pressing process of a molded article of a medium density fiberboard having a curved surface whose curvature radius is about 25 times the thickness of the board according to the present invention.

FIG. 2 is an example of a processed molded product.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Medium density fiberboard 2 Male type 3 Female type 4, 4a Pressure plate

Claims (5)

[Claims] 1. A molded article of a medium-density fiberboard having a curved surface, having a curved surface having a radius of curvature of 50 to 15 times the thickness of the plate. 2. The medium-density fiberboard having a curved surface, characterized in that the medium-density fiberboard is formed of a fiberboard such as a medium-density fiberboard alone, a decorative veneer, a paper, or a cloth. Molded product. 3. The molded article of a medium-density fiberboard having a curved surface according to claim 1, wherein the medium-density fiberboard is formed of a fiberboard which is appropriately painted or colored. 4. The medium-density fiberboard having a curved surface according to claim 1, wherein the medium-density fiberboard is formed by printing or transferring an appropriate pattern. Molded product. 5. A medium-density fiberboard cut into an appropriate shape,
After performing heat treatment with superheated steam at 110 ° C. to 120 ° C. for 10 to 30 minutes, immediately put into a hot press mold having an intended curved surface, pressure 10 to 40 kg / cm ² , temperature 120 ° C.
Under the condition of ~ 250 ° C, the initial pressure is gradually increased until the predetermined pressure is reached, gradually accelerated, pressurized while increasing the pressure, molded, and immediately released from the hot press, immediately exposed to cold air of 5 ° C or less. 5. Finished by rapid cooling.
A method for processing a molded article of a medium-density fiberboard having the curved surface as described above.