JPH03213302A - Regeneration of defective plywood - Google Patents

Abstract

PURPOSE:To regenerate a defective plywood, use resources effectively and increase yield by putting marks along a number of fiber directions on a surface layer section of the defective plywood and applying a bonding agent thereon. CONSTITUTION:A defective plywood 1 consists of a surface plate 3, an intermediate plate 4 and a rear plate 5. The permeation of a bonding agent is made better by putting marks 2 on said plywood 1 along the fiber directions. The marks 2 are cut by rotating a roll having a number of sharp cutters, and a number of marks 2 are cut on the surface layer of the defective plywood 1 by said arrangement. The bonding agent having permeability as good as possible is used and applied on the surface by the spreader coating process or the like to permeate the bonding agent uniformly even into the intermediate plate 4 of the plywood 1. After the bonding agent is permeated, new bases 6 and 7 are thermocompression bonded on the coating surface of the plywood 1 on which the marks 2 are cut. The defective plywoods which other have to be burnt or the like because of the puncture or defective bonding can be regenerated and reused by said arrangement.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for recycling defective plywood, and more particularly, to a technique capable of recycling defective plywood with punctures due to poor adhesion, thereby making it possible to effectively utilize resources.

[Prior Art] and [Problems to be Solved] The cost of logs in plywood manufacturing accounts for a very large proportion of the cost structure, and the product yield has a significant effect on the cost of plywood. For this reason,
Improving yields by reducing waste is an important issue for plywood factories, and each plywood factory is making maximum efforts to improve yields.

On the other hand, there are a few cases in which defective products are produced and yields are reduced due to improper handling such as tearing of the veneer due to drying or subsequent handling, or poor adhesion.

In general, defective plywood includes core separation, electrocardiogram, puncture, poor adhesion, cracked veneer, discoloration, holes, damage,
There are dents, creases, etc.

Although each plywood factory strives to reduce the defective rate by thorough quality control, it is extremely difficult to eliminate defective plywood, and the defective rate at plywood factories is generally high.

Punctures and poor adhesion account for half of the defective plywood.

Currently, defective plywood is sometimes incinerated or only the usable parts are cut out and sold as offcuts, but the cost is so low that it's almost free.

If these punctures and poorly bonded plywood can be recycled, it will contribute to improved yield and effective use of resources.

Conventionally, attempts have been made to recycle defective plywood by inserting a hypodermic needle into the punctured part, making another hole, injecting adhesive, and then hot-pressing the punctured part.

However, the adhesive did not spread to the entire defective area, or the strength of the plywood deteriorated, and the appearance deteriorated, so that it could not be put to practical use.

The present invention aims to recycle defective plywood that would otherwise have to be incinerated due to such adhesion problems, thereby making effective use of resources, improving yields, and further improving the yield rate of defective plywood, which was previously unachievable. The aim is to pave the way for revitalization.

Other objects and novel features of the present invention will become apparent from the description herein and the accompanying drawings.

[Means for Solving the Problems] The present invention involves making a large number of scratches along the fiber direction on the surface layer of defective plywood due to punctures or poor adhesion, applying an adhesive to the plywood and allowing it to penetrate, and then The method for recycling defective plywood is characterized in that a new base material is bonded under heat and pressure to the adhesive-applied surface of the plywood, and preferably, the surface of the defective plywood is rotated by a roll having a blade for making scratches. The present invention resides in a method for recycling defective plywood, which is characterized by making a large number of staggered scratches along the fiber direction at a depth that does not reach the surface of the intermediate board of the plywood on the layer surface.

That is, in the present invention, a large number of scratches are formed along the fiber direction on the surface layer of defective plywood. The reason why scratches are made along the fiber direction when making defects on defective plywood is that if the scratches are made at right angles to the fiber direction, the strength of the plywood will decrease.

Therefore, by creating flaws along the fiber direction, the strength of the plywood is not reduced, and by creating flaws along the fiber direction, the permeability of the adhesive is improved. Therefore, by applying an adhesive, the adhesive penetrates evenly to the middle plate of the plywood, and when a base material such as a new veneer is placed on the coated surface using the adhesive and bonded by heat pressure, the base material is The material further improves the strength, and the base material hides the scratched plywood surface, allowing the defective plywood to be recycled as decorative plywood or the like.

Next, the recycling method of the present invention will be explained with reference to the drawings showing an example. FIG. 2(A) schematically shows an example of plywood in a plan view.

The plywood 1 generally has problems with adhesive properties, such as punctures or poor adhesion.

On the defective plywood 1, as shown in FIG. 2(B),
Makes many scratches 2.

FIG. 2(B) schematically shows the plane of section M in the figure.

FIG. 2(B) shows that the length of the flaw 2 is 30 mm and the pitch is 10 mm.

Although the flaws 2 may be formed continuously, it is preferable to form the flaws 2 intermittently at appropriate pitches in view of the strength of the plywood.

Further, it is more preferable to arrange them in a staggered manner as shown in the figure for the same reason.

The reason why the flaws 2 are provided along the fiber direction is that if the flaws are made perpendicular to the fiber direction, the strength of the plywood will be reduced.

Further, by providing the flaws 2 along the fiber direction, the permeability of the adhesive is improved.

To create the scratches 2, a roll having many sharp blades is rotated, thereby creating countless scratches 2 on the surface of the defective plywood l.

FIG. 3 shows a sectional view taken along line 2--I in FIG. 2(B).

As shown in the figure, an example of the cross-sectional configuration of the defective plywood 1 includes a top plate 3, a middle plate (core) 4, and a back plate 5.

As shown in FIG. 3, the flaws 2 are provided on the top plate 2 and are set to a depth that does not reach the surface of the middle plate 4 in order not to reduce the strength of the plywood.

As shown by dotted lines in FIG. 3, flaws 2 may also be provided on the back plate 5 side.

The flaws 2 may be treated on one or both sides depending on the degree of defect in the defective plywood 1.

Although the illustration is omitted, the top plate 3 of the defective plywood 1
An adhesive layer is interposed between the middle plate 4 and the middle plate 4 and between the middle plate 4 and the back plate 5.

+2 By creating flaws 2 along the fiber direction, the recycling adhesive penetrates into the interior of the defective plywood 1 (.

As the adhesive, various types of adhesives conventionally used for plywood can be used.

The adhesive includes, for example, urea resin9. Examples include adhesives made of melamine urea cocondensation resin, phenol resin, and melamine phenol resin.

In the present invention, a large number of scratches are created on the surface layer of the defective plywood, and the scratches are also created along the fiber direction, so that the adhesive can penetrate into the inside of the plywood. Preferably, an adhesive is used.

The adhesive is applied by a method such as sprayer application.

The adhesive evenly penetrates into the middle plate 4 of the plywood 1. By creating a large number of flaws 2 along the fiber direction, it becomes easier to penetrate into the defective adhesion layer.

After applying the adhesive, apply a new base material to the surface (one side or both sides) of the defective plywood 1 that has scratches 2, for example,
Glue as shown.

As new base materials 6 and 7, for example, veneer or plywood can be used to create recycled plywood, decorative paper can be used to create decorative plywood, sawnboard can be used to create new wood materials, FRP (glass fiber reinforced plastics), plastic If an inorganic material is used, it can be made into a composite material.

The new base materials 6, 7 are bonded using the adhesive used in the above application, and the new base materials 6, 7 are bonded under heat and pressure to the surface of the defective plywood 1 to which the scratches 2 have been made.

The base materials 6 and 7 not only have a decorative effect when recycling defective plywood, but also help improve the strength of the plywood.

According to the present invention, by making a large number of scratches 2 along the fiber direction on the surface layer of defective plywood l as described above and applying adhesive, the inside of the plywood can be fixed without reducing the strength of the plywood. It is possible to recycle defective plywood by uniformly penetrating the adhesive into the material and then bonding it with a new base material using heat pressure. This method allows the recycling of defective plywood that would otherwise have to be incinerated due to punctures or poor adhesion. I can do it.

[Example] Next, examples of the present invention will be shown.

Example 1 A roll using defective 3-braid pole plywood with front and back plates of 1.0 mm, middle plate of 3.6 mm, and a large number of sharp blades along the fiber direction on the front and back plates. Rotate it to make a length of 30 mm on the front and back plates as shown in Figure 2 (B).
Make countless scratches 2 in a staggered pattern with a pitch of 10 mm.
Make it easier for the adhesive to penetrate into the poorly bonded layer.

In this case, as shown in Fig. 3, the depth of flaw 2 is
In order to stay on the adhesive layer between the back plate 5) and the core root 4, a roll having a mechanism that allows fine adjustment of the blade height was used to prevent damage to the core root 4 and a decrease in the strength of the plywood.

An area resin adhesive with good permeability is applied to the front and back surfaces of the plywood with the scratches using a glue applicator (spreader) at a rate of 150 g/m2 per side. 1.0 mm thick lauan veneer was layered above and below it, and this was inserted into a hot press and the pressure was 10 kg.
/cm2 and heat-pressing at a temperature of 110°C for 60 seconds to produce recycled plywood.

As Comparative Example 1, the defective plywood was layered with veneers in the same way without scratching it, and the recycled plywood was tied together.

These plywoods were tested according to the Japanese Agricultural Standards for plywood.

Furthermore, as Comparative Example 2, the adhesive strength of untreated defective plywood was similarly tested. As a result, it was confirmed that the strength of the recycled plywood by the method of the present invention at the defective bonding area was improved as shown in Table 1, and there was no problem in practical use.

Table 1 (): Wood breakage rate in parentheses (%) [Effects of the invention] According to the present invention, defective plywood with punctures due to poor adhesion can be recycled, making effective use of resources, improving quality of life, and reducing costs. It is possible to provide a technology that can reduce this, and its significance is extremely significant.

[Brief explanation of drawings]

Figure 1 is a perspective view of an example of recycled plywood produced by the method of the present invention;
Figure (A) is a plan view of the plywood, Figure 2 (B) is an example arrangement of scratches made along the fiber direction of defective plywood, and Figure 3 is a cross-sectional view of the defective plywood with scratches. . In the figure, 1 is a defective plywood, 2 is a flaw, 3 is a top plate, 4 is a core, 5 is a back plate, and 6 and 7 are new base materials. Note that the symbols other than those mentioned above in FIG. 2(B) indicate dimensions.

Claims (1)

[Claims] 1. After making a large number of scratches along the fiber direction on the surface layer of defective plywood due to punctures or poor adhesion, apply an adhesive to the plywood and allow it to penetrate, and then apply the adhesive to the plywood. A method for recycling defective plywood, characterized by bonding a new base material under heat and pressure to the painted surface. 2. A roll having a blade for making scratches is rotated to make a large number of staggered scratches along the fiber direction on the surface of the defective plywood at a depth that does not reach the middle surface of the plywood. How to recycle defective plywood.