JPH0436524B2 - - 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. Conventional technology and problems When producing decorative veneers by cutting fritchi thinly with a slicer, the sliced veneer may be torn or cracked during cutting, especially at the 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 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 that prevents the cutting from expanding inward into the board. A method of slicing with a wood board approximately 5 mm thick attached to the edge of the fritchi 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 end face of the frit on the exit side of the cutter (for example, Japanese Patent Application Laid-open No. 15302/1983), a mesh sheet is attached to the end face of the frit on the exit side of the cutter. A method of gluing and slicing (Japanese Unexamined Patent Publication No. 57-128506), a method of slicing after forming a resin-impregnated hardened layer on the edge of the frit on the exit side of the cutter (for example, Japanese Patent Application Laid-Open No. 57-77515), etc. Various methods have been proposed and are 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 proposed a sheet with a hardness of 25 to 75 degrees by containing a relatively large amount of inorganic powder filler as a crack prevention sheet in accordance with the earlier application No. 138768/1983. We have proposed a technique to completely prevent cracking by using a synthetic resin sheet prepared within a range of 100°C and slicing it 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. In other words, in order to ensure the occurrence of a good cracking phenomenon to prevent cracking while obtaining sufficient adhesive strength, it is necessary to contain a relatively large amount of an inorganic powder filler such as calcium carbonate as a powder filler. On the other hand, the inclusion of this inorganic powder filler accelerates the wear of the cutting blade and tends to reduce the so-called sharpness early, and the life of the blade is shortened in the cutting tests shown in the examples below. average
The problem was that it ended up being about 3,000 pieces, or at most less than 4,000 pieces. In order to solve the above-mentioned problems, this invention not only can completely prevent rust cracks, but also
The purpose is to increase the life of the knife. Means for Solving the Problems Accordingly, the present invention provides a method for slicing the fritches to a predetermined thickness in a state in which a crack prevention sheet is attached to the end face of the fritches, which is the exit side of the cutter. As a sheet, a synthetic resin sheet containing an organic powder filler in a content range of 5 to 40% by weight and having a hardness of 25 to 95 degrees (measured by a type A hardness tester specified in JIS K6301) is used. The gist of the present invention is a method for cutting slices using a fritsch. In FIG. 1 showing the method of carrying out this invention, 1
2 is a cutting blade, which moves in the direction of arrow A in relation to Fritsch 1,
A thin veneer 3 for decorative purposes etc. is cut by cutting the fritsch 1 thinly. 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 prevention sheet 4 contains an organic powder filler in a content range of 5 to 40% by weight, and has a hardness (measured by a type A hardness tester specified in JIS K6301,
Hereinafter, it will simply be referred to as "hardness." ) is adjusted to a range of 25 to 95 degrees (measurement temperature 25 ± 1 degrees Celsius).
By using a powder filler whose content and hardness are adjusted within this range, when the blade 2 progresses and moves from the fritches 1 to the crack prevention sheet 4 during cutting, it will not cause any damage as shown in FIG. 2. In the same way as the fritches 1, a straight tip 5 is produced in the sheet 4 portion in the direction in which the cutting tool advances, thereby preventing the sheet from escaping from the cutting tool 2 and causing a sudden change in cutting resistance. Ideal cutting is performed without causing any damage. That is, on the cut veneer 3, the cut pieces 4' of the crack prevention sheet 4 remain attached to the end surface of the veneer 3 with an even thickness, and as a result, the veneer 3 without cracks is left on the edge. can get. The organic powder content and hardness of the rust crack prevention sheet used in the present invention are limited to the above ranges for the following reason, which was confirmed from the results of many experiments. In other words, if the content of organic powder is less than 5% by weight or the hardness is less than 25 degrees, it will not be possible to reliably crack the tip during cutting, which will cause defects mainly due to cracks caused by the cutting tool. As a result, peeling of the rust prevention sheet 4 may occur due to peeling and scratching of the nose bar. On the other hand, if the filler content exceeds 40% by weight or the hardness exceeds 95 degrees, tip cracking will occur, but the direction of tip cracking will remain constant despite the nose bar's control of the direction of the tip cracking. As a result, the cutting thickness of the anti-corrosion sheet becomes unstable, which may cause troubles such as peeling and peeling as described above. In particular, if too much filler is contained, the hardness of the rust prevention sheet will increase, but it will also become excessively brittle, making it easy for chipping to occur in the rust prevention sheet when a knife is removed.
This may cause the veneer to break during handling, or the detached pieces of the sheet may adhere to the veneer, resulting in defective products. In the specific implementation of this invention, the preferred organic powder content is 10 to 35% by weight, and the preferred hardness range is approximately 30 to 95 degrees. It is essential that the powder filler contained in the crack prevention sheet 4 is organic.
This is done in consideration of the useful life of the cutting tool. That is, for example, when an inorganic powder filler such as calcium carbonate is used, its inclusion tends to accelerate the wear of the cutting blade and quickly reduce the so-called sharpness, as shown in the examples below. In a cutting test, the tool life was about 3000 sheets, at most.
This is because it will be less than 4000 pieces. Wood flour is cited as the most typical organic powder filler, but other materials such as pulp powder, bagasse powder, and rice husk powder can also be used, and one selected arbitrarily from among them may also be used. It is preferable to use one species or two or more species. Moreover, it is preferable to use these organic powder fillers having as small a particle size as possible. Generally, it is best to use 42 meshes or less. 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. The thickness of the rust crack prevention sheet 4 is not particularly limited either, and an appropriate thickness may be used in consideration of the intended effect for preventing rust cracks and economical efficiency, but it is usually 1.0 to 5.0. A size in the range of about mm is suitable in terms of ease of use. The type of matrix resin constituting the sheet 4 is not particularly limited, but from the viewpoint of price and availability, polyvinyl chloride, ethylene-vinyl acetate copolymer, ethylene-vinyl acetate-vinyl chloride graftomer,
Suitable examples include polyurethane, polypropylene, polyethylene and the like. Among these, those made of polyvinyl chloride resin are preferred 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 due to the adhesion improving effect of containing the organic powder filler in the above range, but in order to further improve this, depending on the type of resin, primer treatment, corona discharge treatment It is also beneficial to perform surface treatments such as 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. 4, 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 approximately 0.1 to 5.0 mm, and is connected to the rust prevention sheet 4.
The holes shall be formed in a regular or irregular arrangement with a pitch of approximately 5 to 10 mm. It is necessary and sufficient that the surface of the rust prevention sheet 4 to be attached to the fritchi 1 is only the end surface on the exit side of the cutter 2 in order to prevent rust. In other words, in order to prevent the edges from tearing during handling, a similar sheet 4 may be attached to both end surfaces or three or four end surfaces of the fritch 1. good. Effects of the Invention As described above, this invention has an organic powder filler with a content of 5 on the end face of the frit which is the exit side of the cutter.
Contained in the range of ~40% by weight and hardness of 25 to 95
By attaching a rust prevention sheet made of a synthetic resin sheet that has been carefully adjusted, and slicing the frits with this sheet attached, the blade advances while slicing the frits thinly and prevents cracks. When the sheet reaches the vicinity of the interface with the prevention sheet, a straight tip crack occurs in the sheet in the direction in which the knife advances, and then the knife enters into this and causes a break. Therefore, the crack prevention sheet is not pushed away by the cutter and is reliably cut immediately. Therefore, the resulting cut veneer has the cut pieces of the sheet firmly attached to its end face with a width equal to the original thickness and a thickness equal to that of the cut veneer. The edges can be completely free from cracks and cracks caused by cutting tools. Unlike the case of pasting conventional wooden boards, the material is homogeneous and has no directionality, so it does not cause cracks, and unlike the case of pasting foam resin sheets or mesh sheets. Stable cutting can be performed without causing problems such as peeling, peeling, and cracking. In addition, in this invention, since organic powder such as wood flour is selected as the powder filler contained in the rust prevention sheet, compared to the case where inorganic powder such as calcium carbonate is used, the wood frit is less and reduce the wear of the slicing cutting tool, greatly increasing its service life. Therefore, it is possible to extend the blade replacement cycle, improve continuous operation, and improve the productivity of cut veneers. EXAMPLE Using various types of rust prevention sheets as shown in the table below, these sheets were each adhered and integrated on the side end surface of a wet oak laminated fritchi 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 coating at a rate of 150 g/m ² , the above-mentioned sheet was placed on the coated surface and cold-pressed for 1 hour. In addition, all rust prevention sheets have a diameter of 1
A large number of gas vent holes with a pitch of 10.0 mm were formed in a staggered arrangement. Next, this sheet-attached fritchi was fixed with a chuck with the sheet-attached surface positioned on the side where the slicer's blade would come out, and the rest was sliced into a veneer with a thickness of 0.3 mm according to the usual method. did.

【table】

[Table] When cutting was performed using the crack prevention sheets of Examples 1 to 10 in the table above, cut pieces of the sheet remained attached to the edges of the cut veneer with an even thickness, A product was obtained that had no cracks at all. In addition, the cutting did not cause troubles such as shearing or peeling of the rust prevention sheet, and stable cutting could be performed while maintaining a sufficient service life of the blade. On the other hand, when the content or hardness of the powder filler is outside the specified range of the present invention according to Comparative Examples 1 and 2, the rust prevention sheet may swell or dislodge, resulting in a large number of cut veneers. Many of them contained small cracks. On the other hand, in Comparative Example 3 in which calcium carbonate, which is an organic powder, was used as the powder filler, the above-mentioned disadvantages did not arise, but the service life of the cutter was shorter than that of the above-mentioned Examples.

[Brief explanation of drawings]

1 to 4 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 the state in which tip cracking occurs when the blade moves from the fritch portion to the crack prevention sheet side, Fig. 3 is a perspective view showing the state of attachment of the crack prevention sheet to the fritch, and Fig. 4 The figure is a partially enlarged front view of the rust crack prevention sheet. FIG. 5 is a cross-sectional view showing how the tip cracking phenomenon occurs when cutting a flitch, and FIGS. 6 to 8 are cross-sectional views showing how various troubles occur when using conventional techniques. 1... Fritsch, 2... Knives, 3... Single plate, 4
...Scatter prevention sheet, 6...Gas vent hole.

Claims (1)

[Scope of Claims] 1. A method of slicing the fritch to a predetermined thickness in a state where a crack prevention sheet is attached to the end face of the fritch, which is the exit side of the cutter, wherein the crack prevention sheet contains an organic powder filler. A fritchi slice characterized by using a synthetic resin sheet containing a synthetic resin sheet containing a hardness of 5 to 40% by weight and a hardness of 25 to 95 degrees (as measured by a type A hardness tester specified in JIS K6301). Cutting method. 2. The method for slicing a fritchi according to claim 1, wherein the rust prevention sheet is made of vinyl chloride resin. 3. The fritsch slicing method according to claim 1 or 2, wherein the organic powder filler is one or more selected from wood flour, pulp flour, and rice husk flour. 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 frits according to any one of claims 1 to 4, wherein the crack prevention sheet has a large number of fine vent holes for degassing on its entire surface.