JPH0439402B2 - - Google Patents

Description

[Detailed description of the invention]

Industrial Application Field This invention manufactures thin veneers such as decorative veneers by thinning a single material fritchi obtained by cutting wood from logs or a composite fritchi obtained by laminating and bonding square timbers, boards, etc. This invention relates to a method of slicing. In this specification, "%" is based on weight. Conventional technology and problems When producing a decorative veneer by thinly cutting fritchi with a slicer, the sliced veneer may be torn or cracked during cutting, especially at the single edge of the fritchi on the side where the cutter exits. Cracks occur easily. For this reason, conventionally, a large number of parallel cuts are made in the end face of the frit on the exit side of the cutter in a direction perpendicular to the cutting direction using a chain saw or chain saw to prevent the progression of cracking. Measures were taken to prevent this from expanding into the interior of the veneer. However, even when such cuts are made, it is still not possible to absolutely avoid the occurrence of harmful cracks that extend to the inside of the veneer surface. Not only that, but the fritch material is wasted by the depth of the cut, resulting in a poor yield.In addition, small pieces torn off from the part where the cut was made when cutting with a slicer adhere to the veneer. There was a problem in that it interfered with the adhesion of the veneer to the substrate in a subsequent process, which tended to cause defects. Due to these problems, the following methods have recently been proposed as improvements to prevent rust cracks. A method of slicing with a wood board approximately 5 mm thick attached to the edge of the fritsch on the exit side of the knife so that the cutting surface is straight-grained. A method of slicing with a foamed synthetic resin sheet such as foamed polyurethane attached to the edge of the fritchi on the exit side of the cutter (for example, Japanese Patent Application Laid-Open No.
No. 15302). A method of slicing after forming a resin-impregnated hardened layer on the edge of the frit on the exit side of the blade (for example, Japanese Patent Laid-Open No. 77515/1983). A method of slicing by gluing a mesh sheet to the edge of the frit on the exit side of the blade
No. 128506). However, when using the above method, there is a problem that the cost of the straight-grained wood boards to be attached to the frits is quite high.In addition, it is not necessarily an ideally homogeneous material; In addition, it could be a cause of rust cracks, so it could not necessarily be a fundamental measure to prevent rust cracks. In addition, in the above method, since the foamed synthetic resin sheet has poor cutting suitability, it has a tendency to get entangled with the cutter and cannot be cut well, and may peel off from the frit (peeling), or may lie in front of the cutter and cause the frit to break off. There were problems such as the nose bar suppressing the cutting surface, which could cause it to be ripped off. Furthermore, in the above method, since the resin-impregnated hardened layer is hard, it may cause the blade to chip or come off the frit.
In other words, the cutting resistance increases rapidly when entering the resin-impregnated hardened layer, and the impact at that time may cause partial tears at the interface of the resin-impregnated layer or so-called cutter cracks over the entire length. There were flaws. Furthermore, even when using the above-mentioned method, there are problems similar to the above-mentioned case of pasting a foamed resin sheet, and good results cannot always be obtained. With the background of the prior art as described above, the present inventors conducted intensive research on further improvement means for preventing cracks during cutting, and as a result, the following findings were obtained. That is, as shown in FIG. 6, when cutting with the fritch 11, a break in the material called a tip crack 13 occurs in advance as the cutter 12 advances, and the cutter 1 gradually
2, the chips 14 are peeled off as the cutting tool progresses, but in order to perform accurate and crack-free cutting, it is necessary to ensure that the tip cracking phenomenon described above occurs, and to prevent it from occurring as the blade progresses. It has been found that it is important to produce it in a straight manner in the direction. Based on this knowledge, we analyzed the problems with the conventional technology and found that when a foamed synthetic resin sheet or a mesh sheet is pasted, or when a resin-impregnated hardened layer is formed, the cutter will not work on the fritted wood part. This is because the occurrence of tip cracking is not observed at the stage of transition from the rust crack prevention sheet adhesive layer or resin-impregnated layer, or even if tip cracking occurs, it does not occur immediately in the direction of travel of the knife. It turned out that this was causing various problems. That is, the rust prevention layer 15 is formed by adhering to the fritch 11 or impregnating it with a resin.
Because tip cracks 13 do not occur or tip cracks tend to occur obliquely, cutting is performed with uneven cutting thickness relative to the prevention layer 15 as shown in FIGS. 7 and 8. In particular, when cutting is performed in the state shown in FIG. 7, the attached part of the prevention layer 15 cannot be removed naturally from between the blade and the nose bar, and if it is forcibly pulled out, it may be torn off. ,
Furthermore, it has been found that the prevention layer 15 is prone to so-called cracking, peeling, etc., such as peeling off from the cut veneer 16 as shown in FIG. Based on the elucidation of the above-mentioned phenomenon, the inventors believe that if it is possible to reliably cause tip cracking and to cause it to occur as quickly as possible in the direction of travel of the cutter, it is possible to We predicted that it would be possible to reliably prevent cracks while avoiding technical troubles, and as a result of various experiments and research, we developed a specific configuration for the material to be attached to the exit side of the Fritsch blade. The present inventors have discovered that very good results can be obtained when using a laminated synthetic resin sheet, and have completed the present invention. In addition, the present inventors have previously applied a synthetic resin crack prevention sheet containing a powder filler and having a hardness in the range of 25 to 75 degrees to the fritches in accordance with Japanese Patent Application No. 61-138768. This application is based on the invention of the above-mentioned earlier application, and proposes a method for performing slice cutting, with the aim of further improving the rust prevention function and increasing the useful life of the cutting blade by reducing its friction. This is an improvement. Means for Solving the Problems This invention is based on the premise that a synthetic resin crack prevention sheet is pasted on the end face of the fritsch, which is the exit side of the blade, and that the fritchie is sliced with this sheet attached. The rust crack prevention sheet is composed of a laminated sheet of a first layer and a second layer, and the first layer side is adhered to the fritch.The first layer contains an inorganic powder filler, and its content is is in the range of 25 to 60%, and the second layer is prepared to have a thickness equal to or thicker than the first layer, and a hardness in the range of 25 to 95 degrees, This is subject to the following conditions. The following Table 1 shows the specified conditions for the upper surface of the rust prevention sheet of the present invention, together with the preferred range of conditions. Note that the underlined items in the table are essential conditions, and the items shown in parentheses are preferred conditions.

【table】

[Table] Next, the present invention will be explained in more detail based on the drawings. In Fig. 1, 1 is a fritchi, and 2 is a cutting blade, which moves in the direction of arrow A in a relative relationship with the fritchi 1, and cuts the fritchi 1 thinly to cut a thin veneer 3 for decorative purposes. to be accomplished. Accordingly, in this invention, a synthetic resin crack prevention sheet 4 is attached to at least the end surface of the fritch 1 which is the exit side of the blade 2 during this cutting, and slice cutting is performed with this sheet attached. do. Here, in this invention, the rust crack prevention sheet 4 has a powder filler content of 25 to 60%.
The first layer 4 made of synthetic resin is contained in a range of % by weight.
a, which is thicker than or the same thickness as the first layer, and has a hardness of 25 to 95 degrees (measured temperature 25 ± 1 degrees Celsius) as measured by a type A hardness tester specified in JIS K6301 (hereinafter simply referred to as "hardness"). A laminated sheet with a second layer 4b adjusted to a range of 1 to 4 is used.
By using the rust crack prevention sheet 4 having such a structure, when the blade 2 moves forward and moves from the fritches 1 to the crack prevention sheet 4 during cutting, it will not break in the same way as the frit 1, as shown in FIG. It is ideal to create a straight tip crack 5 in the cutting tool's advancing direction in the part of the rust prevention sheet 4, without causing a phenomenon in which the sheet escapes from the cutting tool 2, and without causing a sudden change in cutting resistance. Cutting is performed. That is, the cut pieces of the crack prevention sheet 4 remain attached to the cut veneer 3 with an even thickness on the end face thereof, and as a result, an end plate 3 without cracks on the edge portion is obtained. . In the rust crack prevention sheet 4 used above,
The first layer 4a ensures reliable adhesion of the sheet 4 to the fritches 1 and
The second layer 4b has the role of detecting the occurrence of the phenomenon and immediately directing it towards the second layer 4b. In order to fully demonstrate these functions, it is essential that the first layer contains 25% or more of an inorganic powder filler. That is, if the content is less than 25%, adhesion to fritches will be poor and peeling will easily occur during cutting. However, on the other hand, inorganic powder fillers
A content exceeding 60% is not preferable because the cutting blade 2 will wear out prematurely and its useful life will be shortened. The most suitable content range is approximately 30-50%. The inorganic powder filler used here is not particularly limited, but any one type or a mixture of two or more types selected from the group of inorganic powders such as calcium carbonate, clay, and silica can be used. The thickness of the first layer 4a may be extremely thin, as expected from the above function. in particular
A thickness of 0.1 to 0.5 mm is necessary and sufficient. If it is too thin, it will not be sufficient for the above-mentioned function, but if it is too thick, it will shorten the life of the cutter, which is actually harmful. The hardness of the first layer does not significantly affect the effects of the present invention, and therefore is not particularly limited, but is preferably 25 to 75 degrees, particularly preferably 35 to 75 degrees.
It is best to adjust it to about 65 degrees. That is,
If the hardness is too low, the occurrence of straight tip cracking may be inhibited, which may easily cause peeling. On the other hand, if the hardness is too low, the blade 2 will move from the frit 1 to the crack prevention sheet 4. At the stage of transition, the impact becomes large, and this tends to prevent the smooth occurrence of tip cracking or cause peeling. The second layer 4b of the rust crack prevention sheet 4 causes a straight tip crack in the direction of travel of the cutter, and has the main function of preventing rust cracks.
Therefore, it is not necessary to include a powder filler, but rather it is preferable not to include it in order not to reduce the service life of the cutter 3, and even if it is included, the upper limit is kept at most 10% or less. Should. On the other hand, it is important to adjust the hardness of the second layer 4b in order to achieve the above function. That is, the hardness of the second layer 4b must be in the range of 25 to 95 degrees and must be at least equal to or higher than the hardness of the first layer 4a. That is, the hardness is 25
If it is less than 30°, it will not be possible to reliably crack the tip during cutting, which will cause defects mainly due to cracks caused by the blade during cutting, and as a result, peeling and crack prevention sheet 4 due to the nose bar being pulled and inserted.
may cause peeling. On the other hand, when the hardness exceeds 95 degrees, tip cracking occurs, but despite the effect of the nose bar to stabilize the cutting thickness, the direction in which the tip cracking occurs is not constant, and as a result, the cutting thickness of the rust prevention sheet decreases. As a result, problems such as peeling often occur as described above. The most suitable hardness range is about 35 to 90 degrees.
And in the relative relationship with the hardness of the first layer 4a,
Of course, it is preferable that the hardness is higher than that, with a hardness difference of 10 to 55 degrees. Therefore, the hardness of the rust prevention sheet 4 as a whole is mainly controlled by the hardness of the second layer 4b, especially when the thickness of the first layer is considerably thinner than the thickness of the second layer. is almost the same as the hardness of the second layer. In addition, if the thickness of the second layer 4b is too thin, the first layer 4a will have to be relatively thick in relation to the overall thickness required for the rust prevention sheet 4, which will result in a cutlery. The service life will be reduced, and defects such as the cutting pieces of the rust prevention sheet coming off when handling the cut veneer will be more likely to occur. Therefore, it is necessary that the thickness be at least equal to, or preferably thicker than, the first layer. On the other hand, it is also futile to make it too thick. The overall thickness of the rust crack prevention sheet 4 may be determined by considering the initial effect for preventing rust cracks and economical efficiency, but it is usually within the range of 1.0 to 6.0 mm for ease of use. It is also suitable in this respect. In relation to this, the second
The thickness of the layer 4b is preferably set in a range of 0.5 to 5 mm, most preferably in a range of about 1 to 3 mm. The second layer 4b may also be divided in the thickness direction and may have a multi-layer structure. That is, for example, as shown in FIG. 3, the second layer 4b may be composed of two layers, an inner layer 4b' and an outer layer 4b''.In this case, the hardness increases from the inner layer 4b' to the outer layer 4b''. It is recommended that the hardness be made larger and that there be a hardness difference of 10 to 30 degrees between them. Thereby, as the knife 2 advances, it becomes possible to more smoothly produce a straight tip crack in the crack prevention sheet 4 with less resistance. The type of resin that constitutes the rust prevention sheet 4,
In other words, the types of matrix resins for the first and second layers are not particularly limited, but polyvinyl chloride, ethylene-vinyl acetate copolymer, ethylene-vinyl acetate-vinyl chloride are used from the viewpoint of price and availability. Suitable examples include graftomers, polyurethane, polypropylene, polyethylene and the like. Among these, those made of polyvinyl chloride resin are most suitable from the viewpoint of ease of hardness adjustment and cutting suitability. Prior to cutting the flitch 1, the crack prevention sheet 4 must be firmly adhered to the wet flitch 1 at least to the end face of the flitch on the exit side of the cutter 2. This adhesion can be made sufficiently good due to the adhesion-improving effect of containing the powder filler in the above range in the first layer 4a, but in order to improve this, depending on the type of resin, primer treatment is performed. It is also beneficial to perform surface treatments such as , corona discharge treatment, etc. In addition to the laminated fritches shown in the figure, the fritches 1 may be single-piece frits cut from raw wood, but in order to provide suitable cutting properties, wet ones having a moisture content higher than the fiber saturation point are used. Therefore, as the adhesive for pasting the rust prevention sheet 4, it is necessary to select and use an adhesive that is not only easy to cut after curing, but also adhesive that can be bonded to wet surfaces. Needless to say. As the deceptive adhesive, for example, an epoxy resin-based or isocyanate-based moisture-curable polyurethane resin adhesive is suitably used.
In particular, the latter polyurethane resin adhesive is preferably used, but in this case, the adhesive reacts with the moisture contained in the fritch 1 and generates carbon dioxide gas.
To achieve good adhesion, see Figures 4 and 5.
It is desirable to form a large number of gas vent holes 6 over the entire surface of the rust prevention sheet 4 as shown in the figure. This gas vent hole 6 is made large with a diameter of about 0.1 to 5.0 mm, and is placed in the resin sheet 4.
The holes shall be formed in a regular or irregular arrangement with a pitch of approximately 10 mm. The adhering surface of the resin sheet 4 to the fritsch 1 is as follows:
In order to prevent cracking, it is necessary and sufficient to have only the end surface on the exit side of the cutter 3, but for the convenience of handling the cut veneer 3 afterward, in other words, it is necessary to have only the end surface on the exit side of the cutter 3. In order to prevent this from happening, a similar resin sheet 4 may be attached to both end faces of the fritch 1 or to any of three or four end faces. Effects of the Invention As described above, the present invention is characterized in that the crack prevention sheet having the above structure is attached to the end face of the fritchi which is the exit side of the cutter, and the slice cutting of the fritchi is performed with this sheet attached. When the knife advances while cutting the fritchi thinly and reaches near the interface with the crack prevention sheet, a straight tip crack occurs in the sheet in the direction of the knife's movement, and then the knife enters into this and breaks. cause For this reason, the synthetic resin sheet is reliably cut immediately without causing a phenomenon in which the synthetic resin sheet is pushed by the knife and escapes. Therefore, the resulting cut veneer has the cut piece of the synthetic resin sheet firmly attached to its end face with a width corresponding to the original thickness and a thickness equal to that of the cut veneer. The edge of the board can be completely free from cracks and cracks caused by cutting tools. In particular, the rust prevention sheet is made of a first material containing an inorganic powder filler within a predetermined range.
Since it is constructed as a laminated type consisting of a hardness layer and a second layer adjusted to a predetermined hardness range, the first layer guarantees strong adhesion against frizz and ensures that tip cracking does not occur. Since the second layer ensures that the tip crack develops straight in the direction of travel of the cutter, it is possible to achieve the above-mentioned reliable effect of preventing cracks, and the service life of the cutter is not reduced, resulting in good workability. Can be kept. The difference between reattaching conventional wooden boards is that the material is homogeneous,
Since there is no directionality, stable cutting can be performed without causing cracking, and without causing problems such as peeling, peeling, and cracking that occur when pasting foamed resin sheets or mesh sheets. . Example Using rust prevention sheets with various configurations as shown in Table 2 below, each of these was 200 mm wide and
It was glued and integrated into the side edge of a wet oak laminated fritchi with a thickness of 250 mm and a length of 1900 mm. This adhesive uses a moisture-curing polyurethane adhesive on the edge of the fritsch.
After uniformly coating the coating at a rate of 150 g/m ² , the above-mentioned synthetic resin sheet was placed on the coated surface and cold-pressed for 1 hour. Note that the rust crack prevention sheets used were all sheets in which a large number of gas vent holes each having a diameter of 1 mm were formed in a staggered arrangement with a pitch of 10.0 mm. Next, fix the above-mentioned sheet-attached fritchi with a chuck with the resin sheet-attached side positioned on the side where the slicer's blade comes out, and then use the usual method to create a veneer with a thickness of 0.3 mm. Cut into slices.

【table】

[Table] In Table 1 above, Example Nos. 1 to 4, 5 to 8
and 9 to 10, the content of the inorganic powder filler in the first layer was fixed at 30%, 40%, and 50%, and the relative relationship with the change in hardness of the second layer was mainly investigated,
All of the blades had a service life of 5,000 sheets or more, and during that time, no work defects such as cracking, peeling of the crack prevention sheet, or cracking occurred. In Example Nos. 11 and 12, the type of inorganic powder filler was changed, and in Example No. 13, the amount of inorganic powder filler was added to the maximum allowable amount of 60%. Also No. 14 and 15
is a different type of resin. In either case, it was possible to perform defect-free slicing without cracking and while maintaining a sufficient service life of the blade. On the other hand, in Comparative Example No. 1, a wood board was used for the crack prevention layer, and cracks may occur even when cutting less than 5,000 sheets, and the blade becomes weaker due to the decrease in sharpness. There were many crack defects. In Comparative Example No. 2, the rust prevention sheet was composed of a single sheet of PVC resin containing calcium carbonate, and although it was extremely effective in preventing the occurrence of crack defects, it shortened the useful life of the cutter. There were flaws. Comparative example No. 3
is due to insufficient content of inorganic powder filler in the first layer,
No. 4 has too much of the same, No. 5 has too low hardness of the second layer, No.
6 is too high, and No. 7 shows examples of relative imbalance between the thicknesses of the first layer and the second layer, and both are the number of cuttings shown in the section of blade life.
Defects such as peeling, peeling, and cracking of the rust prevention sheet occurred, making it unsuitable to continue the cutting operation in this state.

[Brief explanation of drawings]

1 to 5 show embodiments of the present invention, and FIG. 1 is a perspective view showing the state during cutting;
Fig. 2 is an enlarged cross-sectional view showing how tip cracking occurs when the cutter moves from the frizz portion to the rust crack prevention sheet side; Figure 3 is a sectional view showing a modified example of the rust crack prevention sheet with the frit attached; FIG. 4 is a perspective view showing the rust crack prevention sheet separated from the fritches, and FIG. 5 is a partially enlarged front view of the rust crack prevention sheet. FIG. 6 is a cross-sectional view showing how a tip cracking phenomenon occurs when cutting a flitch, and FIGS. 7 to 9 are cross-sectional views showing how various troubles occur when using conventional techniques. 1... Fritsch, 2... Knives, 3... Single plate, 4
...Saw crack prevention sheet, 4a...First layer, 4b
...Second layer, 4b'...Inner layer, 4b''...Outer layer, 6...
...Gas vent hole.

Claims (1)

[Claims] 1. A method for slicing the fritches to a predetermined thickness with a crack prevention sheet attached to the end face of the fritches, which is the exit side of the cutter,
Moreover, the rust crack prevention sheet has a first layer made of synthetic resin containing an inorganic powder filler in a content range of 20 to 60%, and is thicker than or at least the same thickness as the first layer and has a hardness of 25 to 60%. It consists of a laminated sheet with a second layer made of synthetic resin adjusted to 95 degrees (measured by a type A hardness tester specified in JIS K6301...the same applies hereafter), and the first layer side is glued with the side facing the fritch. A slicing method for fritsch, characterized in that the above-mentioned slicing is performed. 2. The method for slicing a fritsch according to claim 1, wherein the second layer of the rust crack prevention sheet has a hardness equal to or higher than that of the first layer. 3. The second layer of the rust prevention sheet is made up of a plurality of layers, and the hardness gradually increases from the inner layer to the outer layer. 1. The Fritsch slice cutting method described in 1. 4 Claims 1 to 3 claim that the rust prevention sheet is made of vinyl chloride resin.
The method for slicing a fritsch according to any one of Items 1 to 9. 4. The inorganic powder filler is one or more selected from the group of calcium carbonate, clay, and silica. Method. 6. Any one of claims 1 to 5, in which the rust prevention sheet has a large number of fine gas vent holes perforated on its entire surface.
Fritsch's slicing method described in .