JPH0440164B2 - - Google Patents

Description

[Detailed description of the invention]

Industrial Application Field This invention is a method of thinning thin veneers such as decorative veneers by thinning single material frits obtained by cutting wood from logs, or laminated frits obtained by laminating and gluing square timbers, boards, etc. This invention relates to a method of slicing for manufacturing. In this specification, "%" is based on weight. Conventional technology and problems When producing decorative veneers by thinly cutting frits with a slicer, the sliced veneers may tear or crack, especially at the edge of the frits on the side where the cutter exits. is likely to occur. 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 using a chain saw or chain saw in a direction perpendicular to the cutting direction, and these cuts are used to prevent the crack from progressing. A method to prevent it from expanding to the inside of the board, a method for slicing with a wood board approximately 5 mm thick attached to the edge of the fritchi on the exit side of the cutter 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 end face of the frit on the exit side (for example, Japanese Patent Application Laid-open No. 15302/1983), a mesh sheet is glued to the end face of the frit on the exit side of the cutter. There are various methods such as slicing after forming a resin-impregnated hardened layer on the edge of the frit on the exit side of the blade (for example, JP-A-57-77515). A method has been proposed and is in practice. However, the method described above does not completely prevent rust cracks, and the method described above does not prevent peeling of the adhesive sheet for preventing rust cracks (separation phenomenon from the fritchi), and cracking (the cutting surface of the fritchi when placed in front of the cutter). In addition, in the above method, when the cutting tool enters the resin-impregnated hardened layer, the impact generated due to the sudden change in cutting resistance causes so-called pull-out cracking. None of these measures was a fundamental preventive measure against rust cracks, as they could cause cracks and tears. Against this background, the inventors of the present invention have developed a sheet with a hardness in the range of 25 to 75 degrees by containing a relatively large amount of powder filler as a rust crack prevention sheet in accordance with the earlier application, Japanese Patent Application No. 138768/1983. We have proposed a technology to completely prevent cracking by using a synthetic resin sheet prepared in 1999 and performing slicing with the sheet adhered to the end face of the frit. Although this technique is extremely effective for its intended purpose, it has since been discovered that one problem is that it is difficult to obtain sufficient satisfaction in terms of the useful life of the cutting tool. That is, in order to obtain sufficient adhesive strength and ensure the occurrence of a good cracking phenomenon to prevent cracking, a relatively large amount of an inorganic powder filler such as calcium carbonate is preferably contained as the powder filler. However, the inclusion of this inorganic powder filler accelerates the wear of the cutting blade.
There is a tendency for the so-called sharpness to deteriorate early, and in cutting tests such as those shown in Examples below, the blade life is on average about 3000 blades, and at most 4000 blades or less. In order to solve this problem, the inventors of the present invention have further disclosed the following in Japanese Patent Application No. 61-227873 as one of the improvement measures.
The rust crack prevention sheet has a two-layer structure, and the powder filler is dispersed and contained only in the first layer on the side to which the frit is attached to achieve adhesion to the frit and an effect of guiding the direction of cracking, and the second layer is A second improved technique was proposed in which the material was adjusted to be hard without substantially containing the above-mentioned powder filler, and only a straight tip crack was produced. It has been confirmed that the improvement means according to the second proposal can increase the life of the blade to about 6,000 sheets in a cutting test similar to the above. However, in the industrial production of cut veneers, there is an infinitely strong need to improve workability and continuous operation, and in response to the second proposal above, it is necessary to further increase the life of the cutter. In addition, in the previous proposal, it took about 60 minutes to press the rust prevention sheet to the fritch, but it is desired to further shorten this time. OBJECT OF THE INVENTION Therefore, it is an object of the present invention to provide further improvement means in order to meet the above-mentioned demands. More specifically, in addition to being able to completely prevent rust cracks, it is also possible to shorten the pressing time required to attach the rust crack prevention sheet to the fritches to less than 30 to 40 minutes, and to use a cutlery. The specific purpose is to improve the service life to about 7000 sheets or more. Means for Achieving the Object As a means for achieving the above object, the present invention provides a sheet having a laminated structure including a first layer and a second layer, as in the case of the rust crack prevention sheet according to the second proposal. On the other hand, the main feature is that organic powder such as wood flour is used as the powder filler dispersed in the first layer. That is, the present invention provides a method for slicing the fritch to a predetermined thickness with a crack prevention sheet attached to the end face of the fritch, which is the side where the cutter comes out, and in which the crack prevention sheet is attached to the end face of the fritch, which is the side to be adhered to the cutter. The first layer is composed of a synthetic resin layer containing 5 to 40% by weight of an organic powder filler, while the first layer is composed of a synthetic resin layer containing 5 to 40% by weight of an organic powder filler. The gist of the present invention is a fritsch slicing method characterized in that the second layer is a hard synthetic resin layer containing substantially no powder filler. The above-mentioned specified conditions for the rust prevention sheet used in the present invention are shown in Table 1 below along with the preferred range of conditions. Note that the underlined items in the table are essential conditions of the present invention, and the items shown in parentheses represent preferred conditions.

[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. Then,
In this invention, a synthetic resin crack prevention sheet 4 is attached to at least the end surface of the fritch 1 on which the blade 2 comes out during cutting, and slice cutting is performed with this sheet attached. Accordingly, in the present invention, the rust crack prevention sheet 4 preferably includes a first layer 4a made of synthetic resin containing an organic powder filler in a content range of 5 to 40%, and preferably a first layer 4a made of a synthetic resin containing an organic powder filler in a content range of 5 to 40%. A laminated sheet is used with a second layer 4b made of hard synthetic resin that is thick or at least the same thickness and whose hardness is adjusted to be relatively harder than that of the first layer. By using the crack prevention sheet 4 having such a configuration,
During cutting, when the blade 2 advances and moves from the fritches 1 to the crack prevention sheet 4, as shown in FIG. Ideal cutting is performed without producing a straight tip crack 5, causing the sheet to escape from the cutter 2, and without causing a sudden change in cutting resistance. 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 surface thereof, and as a result, a veneer 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
It plays a role of promoting the generation of , and immediately guiding it toward the second layer 4b. In order to fully exhibit these functions, it is essential that the first layer contains 5% or more of organic powder filler. That is, if the content is less than 5%, adhesion to fritches will be poor and peeling will easily occur during slicing. However, if the powder filler is contained in a large amount exceeding 40%, it becomes difficult to form the first layer into a thin layer, and the cohesive force decreases, making it brittle, making it more likely to chip during slicing. Furthermore, in any case, as a result, when the veneer is handled, the crack prevention layer that remains attached to it tends to come off easily, and there is a high risk that cracks will occur inside the veneer. The most suitable content range for the organic powder filler is approximately 10 to 30%. Wood flour is cited as the most typical organic powder filler, but other materials such as pulp flour, bagasse flour, rice husk flour, etc. can also be used, and one selected arbitrarily from among these can also be used. A species or two or more species can be used. Moreover, it is preferable to use these organic powder fillers having as small a particle size as possible. Generally, it is good to use 42 meshes or less, particularly preferably 60 meshes or less. More specifically, it is desirable to select the particle size in relation to the thickness of the first layer 4a, and if the thickness of the first layer is about 0.3 mm, the particle size should be 60 mesh or less,
If the thickness is about 0.2 mm, the thickness is 80 mesh or less.
In the case of about 0.1 mm, one with 170 mesh or less can be suitably used. Further, the organic powder filler may be any material as long as it can be dispersed in the matrix resin without any problems, so its moisture content is not particularly limited, but it is desirable that it be as dry as possible. Specifically, it is desirable to use one with a water content of 15% or less, particularly preferably 8% or less. In this invention, the powder filler contained in the first layer must contain organic powder within the above range, but a small amount of auxiliary inorganic powder filler such as calcium carbonate or clay may be included. It is not something to be excluded. The auxiliary inclusion of the inorganic powder filler contributes to improving adhesion, but since it has a negative effect on the life of the cutter, even if it is included, it is necessary to keep the amount as small as possible, and at least Content exceeding 50% is not permitted. It should preferably be within a range of 15% or less. As such an inorganic powder filler, for example, one type or a mixture of two or more of calcium carbonate, clay, silica, etc. is 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 1.0 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 not cause any particular functional defects, and therefore, there is no upper limit to the thickness defined in this invention. However, if it is too thick beyond 1.0mm,
Although there are concerns that it will have a negative effect on the tip breakability and the life of the cutter, it is rather pointless because there is no advantage that outweighs this. The hardness of the first layer does not significantly affect the effects of the present invention, and therefore is not particularly limited; (same), particularly preferably adjusted to about 30 to 90 degrees. In other words, 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 cutter 2 will be removed from the frit 1 by the crack prevention sheet. At the stage of transition to 4, the impact becomes large,
After all, this tends to hinder the smooth occurrence of cracking at the tip 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 the 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 should be at most 10% or less. should be respected. On the other hand, it is rather 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 is preferably in the range of 25 to 95 degrees, and is preferably at least equal to or higher than the hardness of the first layer 4a. That is,
If the hardness is less than 25 degrees, it will be difficult to produce a reliable tip crack during cutting, and the sheet will be prone to cracking defects caused mainly by the cutter during cutting, resulting in peeling and crack prevention sheets due to scratches on the nose bar. 4 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
It is about 35 to 90 degrees. In addition, in relation to the hardness of the first layer 4a, it is preferable that the hardness is higher than that of the first layer 4a, and a hardness difference of 10 to 55 degrees is maintained. Further, the thickness of the second layer 4b is not particularly limited, but if it is too thin, the first layer 4a may be relatively thick in relation to the overall thickness required for the rust prevention sheet 4. As mentioned above, this is not a good idea as it will be forced to do so. Therefore, it is desirable that the thickness be at least equal to, or preferably thicker than, the first layer. On the other hand, it is also useless to make it too thick.
The overall thickness of the rust crack prevention sheet 4 may be determined by considering the intended effect for preventing rust cracks and economical efficiency, but it is usually easy to use a thickness in the range of about 1.0 to 6.0 mm. It is also suitable in terms of strength.
In this relationship, the thickness of the second layer 4b is
It is preferable to set it in the range of 0.5 to 5 mm, most preferably in the 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 in terms of ease of hardness adjustment, cutting suitability, etc. 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 by the adhesion improving effect of the organic powder filler contained in the above range in the first layer 4a.
In order to further improve this, depending on the type of resin,
It is also beneficial to perform surface treatments such as primer treatment and corona discharge treatment. As the fritches 1, in addition to the laminated fritches shown in the figure, single frits cut from logs may be used, but in order to provide cutting suitability, 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 such an adhesive, for example, an epoxy resin-based or an 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, so in order to achieve good adhesion, it is necessary to As shown in FIG. 5, it is desirable to form a large number of gas vent holes 6 over the entire surface of the rust prevention sheet 4. This gas vent hole 6 has a diameter of about 0.1 to 5.0 mm, and is placed in the resin sheet 4 with a diameter of about 5 to 5.0 mm.
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, it is necessary to prevent breakage from occurring from the edge during handling. In order to prevent this from happening, a similar resin sheet 4 should be placed on both end faces or on three or four end faces of the fritch 1.
It may also be used as something to attach. Effects of the Invention As described above, the present invention is characterized in that a 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 fritchi is sliced while this sheet is 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 progress, 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 pieces of the rust prevention sheet firmly attached to its end face with a width equivalent to the original thickness and an even thickness to the cut veneer, and the veneer The edges of the blades can be completely free from cracks and cracks caused by cutlery. In particular, the rust prevention sheet includes a first layer containing a powder filler in a predetermined range;
Since it is constructed as a laminated type with a second layer made of hard synthetic resin, the first layer guarantees strong adhesion against frizz and ensures the occurrence of tip cracking, while the second layer Since it is ensured that the tip crack develops straight in the direction of movement of the cutter, the above-mentioned reliable effect of preventing cracking can be achieved. Furthermore, in this invention, organic powder such as wood flour is particularly selected as the powder filler contained in the first layer of the rust prevention sheet, so that when inorganic powder such as calcium carbonate is used, Compared to the above, it can improve the adhesion to wood frits and reduce the wear of the slicing cutting tool, greatly increasing its service life. By the way, the pressing time required for adhering to the fritchi is
It is possible to obtain a sufficiently strong bond in less than 30 to 40 minutes, improving work efficiency, extending the cutter replacement cycle, improving continuous operation, and producing cut veneers. It can greatly contribute to improving sexual performance. Example Using vinyl chloride resin as the matrix resin, various types and amounts of powder filler, thickness, hardness, etc. of the powder filler were used to produce rust prevention sheets with various configurations as shown in Table 2. Using the sheets, these were each adhered and integrated on the side end surfaces of wet oak laminated fritches with a width of 200 mm, 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 applying the coating at a rate of 150 g/m ² , the above-mentioned crack prevention sheet was placed on the coated surface and cold-pressed. 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 sheet-attached side positioned on the side where the slicer's blade comes out, and slice into veneers with a thickness of 0.3 mm using the usual method. I cut it. Then, the pressing time required for complete adhesion of the crack prevention sheet to the fritches was measured, and the useful life of the cutting tool was also investigated and compared. The results are shown in the right column of Table 2.

[Table] In Table 2 above, Examples Nos. 1 to 8 are
The powder filler content of the layer was varied in the range of 5 to 30%, and the adhesive pressing time was 40% in each case.
The service life of the cutter was 7000 sheets or more, and during that time no work defects such as cracking, buffing of the crack prevention sheet, or cracking occurred. In Examples Nos. 9 and 10, a small amount of calcium carbonate was added in addition to wood flour as a powder filler, and the effect thereof was investigated. All of them exhibited good adhesion and were satisfactory in their rust crack prevention effect, but the useful life of the cutlery tended to be shorter than those of Examples 1 to 7. . Comparative Example 1 used only calcium carbonate powder as the powder filler, and was inferior to the Examples in both adhesiveness and the service life of the blade. In addition, in Comparative Example 2, due to the excessive content of wood flour, defects such as peeling, peeling, and peeling of the rust prevention sheet occurred at the number of cutting times shown in the section on knife life, and the cutting operation was continued as it was. It was inappropriate to continue.

[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 blade 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 of the rust crack prevention sheet shown 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 the 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... Cutlery, 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)

[Scope of Claims] 1. In a method of slicing the fritch to a predetermined thickness with a crack prevention sheet attached to the end face of the fritch, which is the side where the cutter comes out, The laminated sheet includes a first layer and a second layer located outside the first layer, and the first layer is a synthetic resin layer containing 5 to 40% by weight of an organic powder filler. A method for slicing a fritsch, characterized in that the second layer is a hard synthetic resin layer containing substantially no powder filler. 2. The method for slicing a fritsch according to claim 1, wherein the rust prevention sheet is made of vinyl chloride resin. 3. The organic powder filler of the first layer is one or more selected from wood flour, pulp flour, bagasse flour, and rice husk flour, according to claim 1 or 2. Fritsch's slicing method. 4. The method for slicing a fritsch according to claim 3, wherein the organic powder filler has a particle size of 42 mesh or less. 5. The method for slicing a flitch according to any one of claims 1 to 3, wherein the second layer has a thickness equal to or greater than that of the first layer. 6. The method of slicing a fritsch according to claim 5, wherein the first layer has a thickness of 0.01 to 1.0 mm, and the second layer has a thickness of 0.5 to 5 mm. 7. According to any one of claims 1 to 6, the second layer has a hardness (measured by a type A hardness tester specified in JIS K6301) of 25 to 95 degrees. Fritsch's slice cutting method.