JP2016190494A - Insect proof plywood - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide plywood attaining enough insect proof processed state without using insect proof medicines as much as possible.SOLUTION: A water content of deep central part of plywood in ship out is below 7%. The plywood is made through at least a raw wood processing step, a bonding step and a storage step, and is kept for an appointed period so that the water content of the plywood becomes below 7%. Because harmful insects (particularly Lyctus) can grow in water contents approximately from 30% to 7%, keeping the water content of the plywood before ship out below 7% for an appointed period prevents egg-laying, progress and growth of the harmful insects in the appointed period. Therefore enough insect proof processed states without using insect proof medicines as much as possible in storage are attained, and the insect proof plywood almost without harmful insects inside in a time of shipment can be shipped.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an insect repellent plywood that does not suffer insect damage without using an insect repellent as much as possible.

  Various anti-insect treatments have been tried against conventional pests and pest-controlling pests, and the adhesive contains formaldehyde and has a certain anti-insect effect. In view of the problem of volatile organic compounds, low formaldehyde adhesives have been used, and therefore, a method of incorporating an insect repellent into an adhesive layer for bonding laminated single plates to each other has been adopted (for example, Patent Document 1). reference).

JP 2010-64287 A

  However, in the method using the low formaldehyde adhesive disclosed in Patent Document 1, since the insect repellent is mixed into the adhesive and used, it is difficult for the agent to reach the center of the veneer, and a reliable insect repellent. Not only is there a problem that the effect is not obtained, but also it cannot prevent the invasion of pests from the exposed cut surface after molding of plywood, and it is low formaldehyde, but it uses an insect repellent. However, there is a problem that it is difficult to say that the reduction of health damage to the human body has been achieved.

  The present invention has been made paying attention to such problems, and an object thereof is to provide an insect-repellent plywood in which a sufficient insect-repellent treatment state can be achieved without using an insect-repellent agent as much as possible.

In order to solve the above-mentioned problem, the insect-proof plywood of the present invention is
Insect-proof plywood, characterized in that the moisture content at the time of shipment at the center deep part of the plywood is less than 7%.
According to this feature, the condition that the moisture content at the center deep portion of the plywood is less than 7% is evidence that the plywood has been in a dry state with a moisture content of less than 7% for a long period of time. You can use plywood with confidence just by measuring the average moisture content.

It is a conceptual diagram which shows before it transfers to adhesive agent coating in the manufacturing process of the insect-proof plywood in an Example. It is a conceptual diagram which shows from adhesive application to product finishing in the manufacturing process of insect-proof plywood. It is a conceptual diagram which shows the storage process and shipment in the manufacturing process of insect-proof plywood. It is a figure which shows the moisture content in wood. It is a table | surface which shows the insect pest survival number at the time of maintaining the plywood sample of 100 mm x 100 mm at each water content for about 2 weeks. It is sectional drawing which shows the state which measures the moisture content in a plywood.

  The form for implementing the insect-proof plywood which concerns on this invention is demonstrated below based on an Example.

  The insect-repellent plywood according to the present invention assumes an insect-repellent treatment mainly against the larvae among the pests. Can lay eggs, grow and grow, and about 16% is optimal.

  The plywood storage method and the insect-proof plywood that are not affected by insects from this larva will be described below. As shown in FIGS. 1 to 3, the insect-resistant plywood according to the present invention for insect-repelling treatment, after the procurement of raw wood A (a) and after storage (b), peeling, ball cutting (c), cutting / classification (d), Raw wood processing step consisting of drying treatment (e), control board (f), adhesive application (g), temporary pressure bonding (h), bonding step consisting of thermocompression bonding (i), curing / dimension cutting (j), It is manufactured through a product finishing process comprising a polishing finish (k) and a storage process (l).

  First, the manufacturing process of the insect-proof plywood will be described in detail with reference to FIGS. First, raw wood A such as hiba wood, cedar wood, cypress wood, larch wood, red pine wood, etc., which is a material of plywood, is procured (a) by thinning or importing, etc. and stored in a predetermined storage place for about 2 to 3 months (b ) To move to the manufacturing process. The moisture content of timber at this time is explained by taking cedar as an example. Sapwood in the timber immediately after cutting is 148 to 159%, and heartwood is about 55 to 113%. When the log A is dried, an environment suitable for the growth of the pests is generated in the log A, and there is a possibility that eggs, larvae and adults of the larvae and parasites are infested.

  Subsequently, in the raw wood processing step, the raw wood A stored in the storage wood (b) is peeled off and then chopped (c) by the chainsaw 1 to a predetermined length, and further wigged by the rotary race 2 to be thin The single plate thus formed is cut and classified into a front plate, a middle plate and a back plate (d). In addition, at the time of this peeling / ball cutting (c) and cutting / classification (d), the larva was not controlled.

  Subsequently, the veneer is dried (e) by the dryer 3 at about 190 ° C. In addition, eggs, larvae and adults die at 50-60 ° C., so that the pests parasitizing the log A can be killed at the stage of the drying treatment (e), and the drying treatment (e ) Reduces the moisture content of the veneer to less than 7%, so that the veneer can be made into an environment that is not suitable for the growth of the larvae. For this reason, even if a larva is flying during the drying process (e), egg laying and growth are not performed.

  Furthermore, the veneer which finished the drying process (e) is classified into the front plate B1, the middle plate B2 and the back plate B3 again after selection, repair and joining by the core builder 4 (f), and moves to the bonding step. .

  In the bonding step, first, the adhesive prepared and stirred by the glue mixer 5 is applied and stacked by the spreader 6 on both the front and back surfaces of the middle plate B2 stacked on the even layer (g). The adhesive applied at this time may be mixed with an insect repellent such as cifenotrin.

  The plywood C coated with the adhesive is temporarily press-bonded (h) at room temperature by the cold press 7 and then transferred to thermo-compression (i). In thermocompression bonding (i), the adhesive is thermally cured by pressing the plywood C at a pressure of 8 to 12 kgf / cm <2> by applying a temperature of about 110 to 135 [deg.] C. by the hot press 8 to form the plywood. The In particular, since the plywood C becomes a high temperature in this thermocompression bonding (i), it is possible to kill almost all the larvae.

  After the molded plywood C is cured for about 3 to 7 days, it is cut and processed into a predetermined size by the double saw 9 (j), and the surface is polished smoothly by the polishing finish (k) of the sander 10, and then stored. Move to (l).

  In the storage step (l), the plywood C is stored in the drying chamber 11 that is blocked from the outside air. In the drying chamber 10, the moisture content of the plywood C is measured by a measuring instrument (not shown) here, and is managed and stored so that the moisture content of the plywood C is less than 7%. At least about 2 weeks is desirable, and after that it is shipped (m) as appropriate.

  Next, the state of the moisture content of 7% or less will be described with reference to FIG. The moisture content indicates the moisture state at the cellular level in the wood, and the moisture in the wood includes the bound water in the cell wall 20 and the free water in the cell lumen 21 as shown in (a). It is divided into.

  (A) is wood immediately after cutting, showing that the combined water is saturated and free water is also present to some extent, and the water content is about 50% or more. In addition, since the moisture content varies greatly depending on the type and environment of the raw wood, it is not necessarily about 50%. In addition, an environment having a water content of about 50% or more is not suitable for the growth of the larvae, so that insect damage is unlikely to occur.

  (B) is wood before the drying process (see FIG. 1 (e)), and represents a state in which the drying after cutting has progressed. Since wood begins to evaporate from free water, the free water is completely lost while the bound water is saturated. This is called the fiber saturation point, and the water content is about 30%.

  (C) is the wood after the drying treatment, and in the drying treatment, the moisture content is reduced to less than 7% because the drying proceeds further from the fiber saturation point. And the storage process (refer FIG.3 (l)) mentioned above maintains the state which reduced this moisture content to less than 7%.

  Moreover, as a result of preparing a plywood with different moisture contents and measuring the number of living pests within a certain period from the end of May, which is the egg-laying season of the larvae, as shown in FIG. Furthermore, it was confirmed that the survival rate of the larvae was extremely low in a plywood having a water content of less than 7%. In this test, the survival rate of the larvae after 2 weeks was expressed using a plywood which is a sample of approximately 10 mm × 10 mm having various contents. As is apparent from the graph of FIG. 5, the survival rate peaked at around 16%, and the survival rate of the larvae was hardly confirmed in plywood having a moisture content of less than 7%.

  Thus, the storage method of the plywood C according to the present invention is that the moisture content of the plywood C is in the storage step (see FIG. 3 (l)) in the insect processing plywood manufactured by the raw wood processing step, the bonding step, and the storage step. In order to store the pests in a state of less than 7%, pests (especially oyster beetles) can grow at a moisture content of about 30% to 7%, and the plywood should have a moisture content of less than 7%. Thus, it is possible to prevent the insects from laying, growing and growing, and effectively preventing insect damage in the plywood storage process. In particular, the insect's egg season is 10 to 14 days, after which the larvae will eat through the conduit and cause damage, so that the plywood is kept at a moisture content of less than 7% for at least 2 weeks. The insect repellent treatment state is achieved, and the insect repellent plywood having almost no pests inside can be shipped at the time of shipment.

  In general, when a plywood purchaser performs a construction work using plywood, it is customary to use plywood purchased usually more than two weeks ago to check for pests (especially larvae). Since the product is shipped with an average moisture content of less than 7%, insect damage during the period from purchase to use can be eliminated.

  Further, according to the present embodiment, at the time of shipment, it is ensured that the moisture content in the center deep portion of the plywood is kept in a state of less than 7% and is shipped to the user. The state where the moisture content in the center deep part of the plywood is less than 7% is evidence that the plywood has been in a dry state with a moisture content of less than 7% for a long time. Therefore, as shown in FIG. By inserting the moisture content measuring needle 23 of the moisture content measuring device 22 into the plywood C and measuring the average moisture content in the center deep portion of the plywood, the plywood can be used with confidence.

DESCRIPTION OF SYMBOLS 1 Chain saw 2 Rotary race 3 Dryer 4 Core builder 5 Glue mixer 6 Spreader 7 Cold press 8 Hot press 9 Double saw 10 Thunder 11 Drying chamber 20 Cell wall 21 Cell lumen 22 Moisture content measuring instrument 23 Moisture content measurement needle A Log B1 Table Plate B2 Middle plate B3 Back plate C Plywood

Claims (1)

  Insect-proof plywood, characterized in that the moisture content at the time of shipment at the center deep part of plywood is less than 7%.

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