JPH01113202A - Slicing cutting method of flitch - Google Patents

Abstract

PURPOSE: To increase the usage life of cutlery as well as to prevent sliver by using a plastic sheet with organic powder fillers to a specified amount and hardness adjusted to a specified value as sliver preventing sheet. CONSTITUTION: In cutting, sliver prevention sheet 4 made of a synthesized resin is adhered at least on the end face of flitch 1 to be the leaving side of a cutlery 2. The sheet 4 employed contains organic powder fillers to a content in the range between 5 to 40 wt.% and its hardness (value measured by A type durometer stipulated in JIS K6301) is adjusted within the range of 25 to 95 degrees (at temperature of 25±1 deg.C). As the organic powder fillers, wooden powder is most typical and alternatives include pulp powder, 42 meshes or smaller. As the matrix resin to form the sheet 4, plastics of polyvinyl chloride type is adequate and it is preferred to form many degassing holes 6 all over its surface to achieve good adhesion.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention is a decorative veneer by thinning a single material flitch obtained by cutting wood from logs or a composite flitch obtained by laminating and bonding square timbers, boards, etc. This invention relates to a slicing method for manufacturing thin veneers such as veneers.

Conventional Technology and Problems When producing decorative veneers by thinly cutting flitches with a slicer, the sliced veneers may be torn or cracked during cutting, especially at the edge of the flitch on the side where the cutter exits. Cracks occur easily.

For this reason, conventionally, (1) a large number of parallel cuts are made in the end face of the flitch on the exit side of the blade in a direction perpendicular to the cutting direction using a cutter or chainsaw, and these cuts are used to prevent the progression of cracking. A method to prevent it from expanding inward into the veneer, ■ A method of slicing with a wood board approximately 5g+ thick attached to the end of the flitch on the exit side of the blade 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 flitch on the exit side of the blade (for example, JP-A-56-1
5302), ■ A method of slicing by gluing a mesh sheet to the flitch end face on the exit side of the cutter (Japanese Patent Laid-Open No. 57-1
28506), ■ On the flitch end face on the exit side of the cutter,
Various methods have been proposed and actually practiced, such as a method of forming a resin-impregnated cured layer and then slicing it (for example, Japanese Patent Application Laid-open No. 77515/1983).

However, the method described in ■■ does not completely prevent rust cracks, and the method described in ■■ prevents peeling of the adhesive sheet for preventing rust cracks (separation phenomenon from the flitch), and cracks (separation phenomenon when the adhesive sheet is placed in front of the cutlery). Furthermore, in method (2) above, the flitch is likely to be torn off by the nose bar which suppresses the cut surface of the flitch, and furthermore, in method The so-called number may cause cracks and tears, which are called cracks, and neither of these measures was a fundamental preventive measure against rust cracks.

Against this background, the inventors of the present application 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 complete prevention technique for preventing cracks, which involves using a synthetic resin sheet prepared within a certain range and performing slicing with the sheet adhered to the end face of the flitch. 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,
Although it is necessary to contain a relatively large amount of inorganic powder filler such as calcium carbonate as a powder filler, the inclusion of this inorganic powder filler accelerates the wear of the cutting blade and quickly reduces the so-called sharpness. There was a problem that the life of the blade was about 3,000 sheets on average, and at most 4,000 sheets or less in cutting tests as shown in Examples below.

In order to solve the above-mentioned problems, it is an object of the present invention to not only completely prevent cracking and scale, but also to extend the life of the cutter.

As a means for solving the problem, the present invention provides a method for slicing the flitch to a predetermined thickness with a crack prevention sheet attached to the end face of the flitch, 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 whose hardness is adjusted to 25 to 95 degrees (measured by a type A hardness meter specified in JIS K6301) is used. The gist is a flitch slicing method that is characterized in that it is used.

In FIG. 1 showing the method of carrying out the invention, (1) is a flitch, (2) is a cutting tool, and the flitch (1) is a cutting tool.
The flitch (1) is cut thinly to form a thin veneer (3) for decorative use, etc., in the direction of arrow (A).

Therefore, in this invention, a synthetic resin crack prevention sheet (4) is attached to at least the end face of the flitch (1) which is the exit side of the blade (2) during cutting, and in this sheet attached state, Slice cutting shall be performed.

Here, in this invention, the above-mentioned rust crack prevention sheet (
As 4), the content of organic powder filler is 5 to 40% by weight.
and whose hardness (measured by a type A hardness meter specified in JIS K6301, hereinafter simply referred to as "hardness") is adjusted to be within the range of 25 to 95 degrees (measurement temperature 25 ± 1 ° C.) Use. By using a powder filler whose content and hardness are adjusted within this range, when the blade (2) advances and moves from the flitch (1) to the crack prevention sheet (4) during cutting, the first As shown in Figure 2, the above sheet (
There is a straight tip crack in the direction of blade movement in the part 4) (5)
Ideal cutting is performed without causing the sheet to escape from the cutter (2) and without causing a sudden change in cutting resistance. That is, the cut pieces (4') of the rust crack prevention sheet (4) remain attached to the cut veneer (3) with an even thickness on the end surface, and as a result, the cut pieces (4') of the crack prevention sheet (4) remain attached to the edge. Veneer without (
3) is obtained.

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, and defects will mainly occur during cutting, such as cracks caused by the cutter. 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, when the filler content exceeds 40% by weight or the hardness exceeds 95 degrees, tip cracking occurs, but the direction of tip cracking remains 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 more likely that the chipping will occur in the rust prevention sheet when a knife is removed. During handling, the veneer may be torn, or pieces of the sheet may fall off and adhere to the veneer, resulting in defective products.

In the specific implementation of this invention, the preferred organic powder content is O 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. This is because, in tests, the life of the knife is about 3,000 sheets, or at most 4,000 sheets or less.

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. 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. -It is best to use 42 mesh or less for crotch meat.

Further, the organic powder filler may be any material as long as it can be dispersed in the matrix resin without any trouble, 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 a material 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 and economical efficiency for preventing rust cracks, but it is usually 1. A range of about .0 to 5.0 is suitable from the viewpoint 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, polyurethane, polypropylene , polyethylene, etc. are listed as suitable materials. 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 blade (2).

This adhesion can be made sufficiently good by the effect of improving adhesion by containing the organic powder filler in the above range. but,
In order to further improve this, it is also useful to perform surface treatments such as primer treatment and corona discharge treatment depending on the type of resin.

For the flitch (1), in addition to the laminated flitch shown in the figure, a single flitch cut from raw wood may be used, but in order to impart cutting suitability, a wet one with a moisture content above the fiber saturation point is used. . For this reason, as the adhesive for pasting the rust prevention sheet (4), select an adhesive that is not only easy to cut after curing, but also can be bonded to wet surfaces. It goes without saying that this should be done. 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 flitch (1) and generates carbon dioxide gas, so in order to achieve good adhesion,
As shown in Figures 3 and 4, the rust prevention sheet (4
) It is desirable to form a large number of gas vent holes (6) over the entire surface. This gas vent hole (6) has a straight I0.
The size is about 1 to 5.0 m, and these are perforated and formed in the rust prevention sheet (4) in a regular or irregular arrangement at a pitch of about 5 to 1°.

In order to prevent rust cracks, it is sufficient that the adhesive surface of the rust prevention sheet (4) to the flitch (1) is only the end surface on the exit side of the knife (2), but the cut veneer (3) For convenience in subsequent handling, that is, in order to prevent tears from occurring at the edges during handling, a similar A sheet (4) may also be attached.

Effects of the Invention As described above, the present invention is characterized in that the end face of the flitch, which is the exit side of the cutter, contains an organic powder filler in a content range of 5 to 40% by weight, and has a hardness adjusted to 25 to 95 degrees. A rust prevention sheet made of a synthetic resin sheet is attached,
By slicing the flitch with this sheet attached, when the blade advances while slicing the flitch thinly and reaches the vicinity of the interface with the sasawa prevention sheet, the sheet is cut in the direction of the blade's movement. A straight tip crack occurs, and then the knife enters into this, causing a break. For this reason, the crack prevention sheet is reliably cut straight without causing a phenomenon in which it escapes due to being pushed by the blade. Therefore, the resulting cut veneer has the cut pieces of the sheet firmly attached to its end face with a width equivalent to the original thickness and a thickness equal to that of the cut veneer, and there are no cracks or cracks on the edge of the veneer. It is possible to completely eliminate the occurrence of 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. Lost,
Stable cutting can be performed without any problems such as peeling or 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, wood flitch is less Improves adhesion to and reduces wear on slicing cutting tools,
Its service life can be significantly increased. Therefore, it is possible to extend the blade replacement cycle, improve continuous operation, and improve the productivity of cut veneers.

EXAMPLE Using rust prevention sheets with various configurations as shown in the table below, these were each coated with a width of 200 mm, a thickness of 250 mm,
It was glued and integrated into the side end face of a 1900m long wet oak laminated flitch.

This adhesion was carried out by uniformly applying a moisture-curing polyurethane adhesive to the end face of the flitch at a rate of 150 g/m, then placing the above-mentioned sheet on the coated surface and cold pressing for 1 hour.

In addition, all of the rust prevention sheets have a diameter of IIn! 1
A large number of gas vent holes with a pitch of 10. Those formed in a staggered arrangement of □m were used.

Next, this sheet-attached flitch was fixed with a chuck with the sheet-attached side positioned on the side where the slicer's blade would come out, and the rest was sliced into 0.3-thick veneer plates according to the usual method. did.

[Left below] (Note 1) PVC: Polyvinyl chloride resin EVA: Ethylene-vinyl acetate copolymer PP: Polypropylene (Note 2) Hardness: A specified in JIS K6301
Measured value using a mold hardness meter (Note 3) Charcoal: Calcium carbonate Wood powder, rice husk powder, pulp powder: Particle size 42 mesh or less, moisture content approximately 5% (Note 4) Knife life: Basically, the sharpness of the knife The evaluation is based on the number of slices (number of slices) until the cut surface of the veneer becomes rough due to the decrease in cutting strength.

In addition, those marked with a chestnut mark are blades. The sharpness is within an acceptable range, but Slice cutting exceeding the number of cuts If you continue to use the rust prevention sheet Do not use the product as it is due to the failure of the product. up to the point where it becomes impossible to use The evaluation was based on the number of cuts.

Also, items marked with an asterisk are the same. The sharpness of the knife is within an acceptable range. However, the number of cuts exceeds the number of cuts. Continuing to cut will prevent cracks. The sheet is chipped and remains as it is. until it reaches a state where it is no longer possible to use it. The evaluation was based on the number of cutting times.

When cutting was performed using the rust crack prevention sheets of Examples 1 to 10 in the table above, the cut pieces of the sheet remained attached to the edges of the cut veneer with an even thickness, and there was no rust crack at all. I got something. 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, in Comparative Examples 1 and 2 in which the content or hardness of the powder filler is outside the specified range of the present invention, the rust crack prevention sheet may swell or dislodge.
Among the large number of cut veneers, many had cracks. On the other hand, Comparative Example 3 in which calcium carbonate, which is an organic powder, was used as the powder filler did not have the above-mentioned disadvantages, but the service life of the cutter was shorter than that of the above example.

[Brief explanation of the drawing]

Figures 1 to 4 show embodiments of the present invention, with Figure 1 being a perspective view showing the state during cutting, and Figure 2 showing the tip when the blade moves from the flitch portion to the rust prevention sheet side. FIG. 3 is an enlarged cross-sectional view showing the state in which cracks have occurred, FIG. 3 is a perspective view showing the state of attachment of the crack prevention sheet to the flitch, and FIG. 4 is a partially enlarged front view of the crack prevention sheet. FIG. 5 is a sectional view showing how the tip cracking phenomenon occurs when cutting a flitch, and FIGS. 6 to 8 are sectional views showing how various troubles occur when using conventional techniques. (1)...flitch, (2)...knife, (3)...
・Veneer board, (4)...Saw crack prevention sheet, (6)...
・Gas vent hole. The above figures are as follows:

Claims (5)

[Claims] (1) In a method of slicing the flitch to a predetermined thickness with a crack prevention sheet attached to the end face of the flitch that is the exit side of the cutter, the crack prevention sheet contains an organic powder filler with a content of 5 to 40%. % by weight, and has a hardness of 25 to 95 degrees (A specified in JIS K6301).
A flitch slicing method characterized by using a synthetic resin sheet adjusted to a value measured by a mold hardness meter. (2) The flitch slicing method according to claim 1, wherein the rust crack prevention sheet is made of vinyl chloride resin. (3) The flitch 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 flitch slicing method according to claim 3, wherein the organic powder filler has a particle size of 42 mesh or less. (5) Slicing of the flitch according to any one of claims 1 to 4, wherein the rust crack prevention sheet has a large number of fine gas vent holes perforated on its entire surface. Method.