JPS5941203A - Manufacture of flitch - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical field The present invention belongs to the field of manufacturing technology for so-called laminated veneers, which is the manufacture of veneers made of precious wood that is higher grade than low-grade wood.

(b) Background technology veneers are produced by cutting raw material veneers from logs, decoloring and dyeing them as necessary, and then laminating them with an adhesive interposed, and having an uneven surface. It was manufactured by clamping it between mold plates (conventionally, this clamping was done with 'UAL), forming it into flitches, and slicing it. However, in the manufacturing process of 71 Tsunosen, poor adhesion between raw material veneers occurred, resulting in a poor yield when sliced small plates were obtained.

The reason for this was thought to be mainly due to the non-uniform distribution of applied pressure during the manufacturing process of the flitch. It was thought that the cause of this non-uniformity of applied pressure was the use of a mold plate having an uneven surface. In other words, the non-uniformity of the applied pressure that occurs when manufacturing flitches using a mold plate with an uneven surface is because the mold has a curved surface like a gutter, and because the thickness of the raw material veneer is constant. This occurs because pressure is concentrated on both sides of the mold, and it is difficult to apply pressure to the center of the mold. However, the use of a mold with an uneven surface is an essential condition when manufacturing laminated veneer, and this cannot be stopped. Therefore, there was a need for the development of a method for eliminating flitch adhesion failure while using a mold plate having an uneven surface.

(c) Purpose of the Invention This invention was made based on the following circumstances, and was made for the purpose of providing a method for manufacturing a flitch that attempts to equalize the load pressure that causes the above-mentioned adhesion failure.

(d) Disclosure of the Invention In order to eliminate poor adhesion of flitches, the present invention first employs a heating and pressing method in the pressing process.

Then, a method was adopted in which the flitch was manufactured by first heating the part of the mold plate having an uneven surface where the applied pressure was concentrated, and then uniformly heating and pressing the entire part to harden the entire part. Furthermore, a high-frequency heating method was adopted to perform such local heating.

A detailed explanation will be given below based on the drawings shown as examples.

FIG. 1 is a schematic diagram for explaining the pressing process. Here, reference numeral 1 indicates a mold plate having an uneven surface, and reference numeral 2 indicates a pile of raw material veneers laminated with an adhesive interposed therebetween. 3 indicates an electrode plate for high frequency heating. The electrode plate 3 is attached to the surface of a mold plate having an uneven surface. This is divided into several upper and lower collars, arranged in such a way that local heating is possible. In the pressing process in the flitch manufacturing process, the pile of raw material veneers is pressurized, and first, the poles Fj, 3
The outside portion B of the veneer pile is heated by b. When the material has softened to a certain degree, the pressure is released once as necessary and then the pressure is applied again to heat the central portion A.

In this case, the electrode plate 3a is used. And then the electrode plate 3
d is also used and the whole is heated. Although the electrode plates 3 are illustrated as being separated from each other in the drawings, it is actually preferable that they be placed in close contact with each other with an insulating material interposed therebetween. The electrode plates are arranged vertically in correspondence with each other so that the necessary local heating can be achieved. Heating by each electrode plate shall be done by electrical means.

The material mechanical properties of wood (elastic modulus, plastic modulus, yield stress, etc.) are affected by the moisture content and material temperature, and the higher the material temperature, the lower the physical properties. Therefore, in the case of this invention, the pressure concentrated areas on both sides of the concave-convex mold plate that correspond to the high pressure load area are softened by partial heating in advance, so only low stress is generated against strain, and the pressure is equalized as a whole of the flitch. is achieved. Therefore, when a flitch is manufactured by heating using the method described above, bonding failures caused by non-uniformity of pressure during pressing, as in the conventional method, are reduced. Furthermore, it was also possible to eliminate pattern collapse caused by poor adhesion of fringe and chi, which often occurred in the past.

(e) Example [Part I] The experiment was carried out using a sinusoidal mold plate having an uneven surface as shown in FIG. The end angle is 26°7°, and the molding pressure is 20kg/cn! Met. For the veneer, 50 pieces of agathis wood (45% moisture content) with a width of 200 mm and a thickness of 1 mm were used.

First, 5 M + (z, 4ooVO high frequency load ￲￥J2
A voltage was applied to the electrode 3b in the figure for 2 minutes (hereinafter referred to as preload). Next, once the pressure was released, a high frequency load under the same conditions as above was uniformly applied to the whole, and uniform heating and pressing were performed.

As a result of the above, the pressure distribution (σn-1) is 2.3 kg/c
It was nl. However, in a separate experiment for comparison, the pressure distribution when no preload was applied was 10.5 kg/cl.

Note that when a laminated veneer was obtained by slicing the obtained flitch, no defects due to poor adhesion occurred when preload was applied. However, about 6% of the veneers that were preloaded and heated indoors had defects of about 6%.

[Part 2] The same procedure as [Part 1] was carried out except that the preload conditions were 5 MHz, 400 V, and 2 minutes, and the molding pressure was 15 kg/cnl. As a result, the pressure distribution is 1, (J
kg/cnl. However, when carried out without preloading, the pressure distribution was 5,7 kg/C.
%Met. The defective rate of the veneer was the same as above.

(to) Effect This invention is a collection f1'! In the manufacturing method of the board - ζ, when pressing the raw material veneer using a mold plate with an uneven surface to form a flitch, the parts with high load pressure are heated to a certain degree in terms of pressure distribution, and then the whole is heated under heating pressure. Since the adhesive is characterized by being tightened, it has the effect of reducing adhesion failures.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of the pressing process in the manufacturing process of laminated veneer.
FIG. 2 is a sectional view of an embodiment of a mold plate having an uneven surface. 1 is a mold plate having an uneven surface 2 is a laminated pile of small raw material plates 3 is an electrode plate Patent applicant Matsushita Electric Works Co., Ltd.

Claims (2)

[Claims] (1) In the manufacturing method of laminated veneer, when pressing the raw veneer to flitch using a molding plate with an uneven surface, after applying heat in advance to the areas with high load pressure in terms of the pressing pressure distribution. A flitch manufacturing method characterized by heat-pressing the entire part. (2) By using a mold plate with a convex and concave surface on which a plurality of divided electrode plates are provided, high frequency heating is applied in advance to the areas with high load pressure, and then the entire body is heat-pressed. A method for producing a flitch according to claim 1.