JP2745471B2 - Manufacturing method of dry fiber board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for obtaining a fiber board by applying a thermosetting resin adhesive to a wood fiber, forming it into a mat by a dry method, and hot-pressing with a hot press. Regarding the manufacturing method.

[0002]

2. Description of the Related Art Conventionally, in a dry fiberboard manufacturing method, when a wood fiber mat is hot pressed by hot pressing as shown in FIG.
(B) Place the fiber mat (d ) between the boards and
The procedure of interposing a thickness bar (c) having a height corresponding to the final thickness of (d ') has been taken.

Further, according to a general dry manufacturing method of a fiber board, the mat is rapidly pressed in an initial stage of pressing by a hot platen, and at the same time, the surface layer of the mat is plasticized by heat to be compressed, and the surface of the product is compressed. Is higher than the core layer, but the surface density is known to decrease as the product density decreases.

[0004]

The decrease in the surface density of this type of fiber board means a decrease in the fineness and smoothness of the board surface, and the coating and the overlay of the decorative material can be performed beautifully. In addition to this, there is a problem in that the physical and mechanical properties such as the hardness and bending strength of the product surface are reduced, and the use of the product board is naturally restricted.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a fiber board which can easily be used to obtain a dry fiber board having a high surface density even for a product having a low density and which can be advantageously used for a wider range of applications. It is.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a fiber mat obtained by applying a suitable adhesive to defibrated wood fiber to a hot platen temperature of 160-2.
In hot pressing of the mat between hot presses at 00 ° C., in the initial stage of hot pressing, the mat is rapidly overpressed until its density increases from 0.05 to 0.30 g / cm ³ above the product density. In this case, the hot plate is immediately opened to the position corresponding to the predetermined product thickness. In this case, the degree of over-pressing is determined in such a manner that the mat has a predetermined thickness within 30 seconds. The pressing time must be in the range to return.

[0007]

In the production method of the present invention, the thickness of the mat is 0.05 to 0.30 g / cm ^{3 in the} initial stage of pressing without using the thickness bar seen in the conventional hot press.
By over-pressing to a high density, the mat surface layer is plasticized by heat and compression proceeds, so that not only high-density products (density 0.6 to 0.7 g / cm ³ ) but also low-density products (density 0.3 to 0.5 g / cm ³ ), the surface density is kept high, and an excellent effect of obtaining a product excellent in both surface hardness and bending strength is obtained.

[0008]

EXAMPLES The method of the present invention will be described in more detail with reference to Examples 1 to 2.

[0009] (1) The wood fibers coated urea resin adhesive defibrated the wood fibers by a conventional method and forming the mat by a dry method, heat mats prepress Release Temperature 190 ° C. hot pressing on , Product thickness 15mm,
Upon that Naruban low density fiber board product density 0.64 g / cm ^3, after raising the mat density in the initial stage of the hot press to a 0.73 g / cm ³ of 0.09 g / cm ³ widening immediately The hot platen was gradually pulled up to return the mat to a predetermined product thickness, and in this state, hot pressing was further continued for 120 seconds to obtain a target fiber board. In this case, the time required for the over-pressing mat to return to the predetermined product thickness (15 mm) was 20 seconds.

The flexural strength of this fiberboard was measured to be 410 g / cm ² , and the flexural strength of a fiberboard of the same specification by the conventional manufacturing method was 360 g / cm ^2.
As much as 50 g / cm ² was observed as compared with

(Part 2) A wood fiber coated with a melamine resin adhesive is dry-formed into a mat shape, and the mat obtained by pre-pressing is set on a hot press at a hot plate temperature of 190 ° C. to obtain a product having a thickness of 15 mm. In order to obtain a low-density fiberboard having a product density of 0.44 g / cm ³ , the mat density in the initial stage of hot pressing is increased by 0.24 g / cm ³ to 0.68.
g / cm ³ , immediately open the hot platen to return the mat to the predetermined product thickness (15 mm),
The target fiber board was obtained by continuing the hot pressing for 0 second. In this case, the time required for the overpressure mat to return to the predetermined product thickness was 25 seconds.

The bending strength of this fiber board is 224.
g / cm ² , and a Shore hardness of 77 on the surface of the product, which was significantly higher than the flexural strength of 174 g / cm ³ and the Shore hardness of 55 of the fiberboard of the same specification by the conventional manufacturing method.

FIG. 1 is a graph showing the relationship between the thickness of the wood fiber mat (board) and the hot pressing time in the production method of the present invention. It is preferable that the return (restoring) time of the over-pressed mat in the initial stage of the heat-pressing be approximately 30 seconds or less. Is worse, and a board having a predetermined thickness cannot be obtained.

[0014]

As is clear from the above description, the method for manufacturing a dry fiber board according to the present invention is a low-density fiber board unlike the conventional method using a thickness bar. Also, there is an excellent effect that high bending strength and surface hardness can be obtained.

[0015] This means that a low-density fiber board having excellent board surface smoothness and excellent surface decorativeness can be obtained, and thin plywood has so far been used as a lightweight wood material for furniture and the like. The flash panel, which had only been available, can be replaced by the fiber board obtained by the method of the present invention, and a remarkable effect that the range of applications in the field of fittings and furniture can be greatly expanded can be expected.

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between mat thickness and hot pressing time.

2A is an explanatory view showing a process before and after pressing of a mat in a conventional hot press, and FIG. 2B is a graph showing a relationship between a mat thickness and a thick tightening time in this case.

[Explanation of symbols]

(B) (b) Upper and lower hot plates (c) Thickness bar (d) Fiber mat (d) board

Claims (1)

(57) [Claims] In a process of hot-pressing a wood fiber mat coated with an adhesive by a hot press at a hot plate temperature of 160 to 200 ° C. to produce a fiber board, the density of an initial stage of hot pressing is a product. 0.05-0.30g from density
/ Cm ³ was over squeezing until rises, immediately heating plate product
A method of manufacturing a dry fiber board, comprising returning to a thickness position and continuing hot pressing for a predetermined time to form a plate.