JP2006069597A - Recycle pallet for cargo work and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recycle pallet made by reusing a used-up wood pallet and a manufacturing method for the recycle pallet which reduce recycling costs and load against the environment substantially. <P>SOLUTION: The component material of a used-up wood pallet for cargo work is crushed to pieces by a crusher to provide wood pieces, which are then pressure bonded together by heat via a natural binder composed in principle of a starch to form deck boards of a given size. The deck boards are used as a top board 1 and a bottom board 2, which are arranged and fixed on both upper and lower surfaces of vertical beams 3 that keeps the gap between the boards 1, 2. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a pallet used for a cargo handling operation by a forklift, and more particularly to a recycled pallet that reuses a used wooden pallet and a manufacturing method thereof.

  Wooden pallets, which are indispensable for forklift trucks, deteriorate over time and cannot be used, but many of them are left unattended due to high disposal costs and lack of a collection system. This is the current situation. In particular, with the revision of the law, small-scale incinerators cannot be used, and the number of pallets left unattended tends to increase.

  In addition, there are countries and regions that require heat treatment and fumigation treatment to prevent the transfer of pests contained in packing materials for wooden pallets used for export. Substitution is progressing. However, the manufacture of plastic pallets requires a large mold, which increases the manufacturing cost and is relatively expensive, and because of the use of a synthetic resin with a large specific gravity, the weight is significant, and handling Is troublesome.

  A pallet manufactured by particle board or MDF (Medium Density Fiberboard) contains an organic solvent in the adhesive, and has a large environmental load when discarded.

When producing a particle board or MDF, secondary crushing, a selection process, etc. are required after primary crushing, and enormous capital investment and processing time are required. Moreover, in addition to wooden pallets for the reuse of general waste materials, waste wood generated at the time of house renovation is used as disclosed in the following patent document, but in construction waste materials, in addition to paint, In the treatment, there are many cases including a polyvinyl chloride film or the like, which is likely to affect the environment, and the removal of foreign matters becomes a problem.
JP 2003-175506 A

  The wood-like molded body in the above-mentioned patent document is obtained by binding a recycled crushed wood having a length of 2 to 40 mm via a synthetic resin binder such as polyethylene, polypropylene, polyamide, PET resin, polyvinyl chloride, and the like. Reprocessing when the recycled molded product deteriorates and cannot be used is a problem.

  A first object of the present invention is to effectively utilize a used wooden cargo handling pallet in a neglected state as a recycled pallet.

  A second object of the present invention is to provide a recycled pallet that exhibits high quality and sufficient strength by minimizing the trouble of removing foreign substances by using only a used pallet as a starting material.

  It is a third object of the present invention to provide a cargo handling recycling pallet that can reduce the cost required for regeneration and can greatly reduce the load on the environment.

  The fourth object of the present invention is to provide a cargo handling recycling pallet which does not require heat treatment or fumigation.

  If the structure of this invention for achieving the said objective is explained in full detail, the invention which concerns on Claim 1 will grind | pulverize the constituent material of the used wooden cargo handling pallet with a crusher, and the said chopped wood pieces will be starched together. A deck board of a predetermined size is formed by hot-pressing it with a natural binder mainly composed of glue, and the deck board is used as a top plate and a bottom plate, and is arranged and fixed on both upper and lower sides of a vertical girder that keeps a gap. It is a recycling pallet for cargo handling.

  The invention according to claim 2 is mainly composed of starch paste for the first step of chopping the components of the used wooden cargo handling pallet with a crusher, and the chopped wood pieces obtained by the first step. The second step of spraying the natural binder and mixing the two with a stirrer to form a film of the natural binder on the peripheral surface of the chopped wood piece, and after the completion of this second step, A third step of producing a deck board having a predetermined size by laminating the aggregate and performing hot pressing for 10 to 20 minutes under a temperature condition of 150 to 200 ° C. by hot pressing, and obtained by this third step And a fourth step of obtaining a recycled pallet using the deck board as a top plate and a bottom plate.

  The recycling pallet for cargo handling of the present invention uses a used wooden pallet as a starting material, and only the nails secure the top plate, bottom plate and stringer, so foreign matter removal can be easily processed with a magnet. can do. In this respect, it is possible to solve the problems caused by other methods using construction waste containing various miscellaneous materials, and of course, it is possible to eliminate the state of leaving the used wooden cargo handling pallet.

  Moreover, since the chopped wood pieces obtained by primary crushing of the used wooden pallet are used, the cost required for regeneration can be significantly reduced as compared with the case of a recycling board in which a multistage crushing process is indispensable. Furthermore, it is a natural binder mainly composed of starch paste that binds the chopped wood pieces together, so it can reduce the environmental burden when disposing of the recycled pallet, and can also be hot-pressed during the manufacturing process. Since the hot pressing is performed under a temperature condition of 150 to 200 ° C., it is not necessary to further perform fumigation or heat treatment even if used for export.

Hereinafter, embodiments of a cargo handling recycle pallet and a method for manufacturing the same will be described in detail.
FIG. 1 is a perspective view showing an embodiment of a recycling pallet for cargo handling according to the present invention, in which a top plate and a bottom plate are respectively arranged and fixed on both upper and lower surfaces of a stringer that holds a space. Reference numeral 2 denotes a bottom plate, and 3 denotes a longitudinal girder.

  At least the top plate 1 and the bottom plate 2 constituting the cargo handling pallet of the present invention use the constituent materials of the used wooden cargo handling pallet. That is, the used wooden load handling pallet is subjected to a crusher using a uniaxial crusher method or a screw shear method, and the thickness direction size is 0.1 mm to 20 mm, the width direction size is 0.1 mm to 40 mm, the length direction A deck board of a predetermined dimension is formed by slicing in the range of 1 mm to 100 mm, and heat-pressing the chopped pieces of wood together with a natural binder mainly composed of starch paste. 1 and the bottom plate 2 are disposed on both upper and lower surfaces of a vertical girder 3 that keeps a distance, and fixed by nails or the like to obtain a recycling pallet for cargo handling of the present invention.

Next, a method for manufacturing a cargo handling recycling pallet will be described in order.
[First Step] A used wooden cargo handling pallet is chopped by a crusher. About 90% of the wooden pallets are broad-leaved trees from Southeast Asia, and 10% are coniferous trees. However, there is no problem even if these are mixed as old pallets for regeneration. Used old pallets are shredded by a crusher, but the operation is performed by rotating a hammer attached to the main shaft and finely shattering it, although it is not uniform due to the hammering force of the hammer. In addition to the crusher method, the crusher can be a crusher using a screw shear method.

  The finely chopped chopped wood pieces are passed through a screen having a relatively large sieve mesh, and the magnets are used to magnetically remove nails mixed in the old pallet. In general, the chips used for the particle board must be finely sized by the multi-stage crushing process of the primary crushed chip, and the size should be uniformed. Is used.

  As described above, the pieces of wood that have been chopped by the crusher and passed through the screen are within the ranges of 0.1 mm to 20 mm in the thickness direction, 0.1 mm to 40 mm in the width direction, and 1 mm to 100 mm in the length direction. Although it is various, most of them have an elongated stick shape and are long in the fiber direction, so that a strong recycling pallet can be obtained by a subsequent hot pressing process or the like.

[Second Step] A natural binder mainly composed of starch paste is sprayed on the finely chopped wood pieces obtained in the first step, and both are mixed with a stirrer. Form a coating. As the natural binder, corn starch or wheat flour is preferably used. Of course, corn starch or wheat flour may be used alone or in combination.

  The spray amount of the natural binder is not uniform depending on the temperature and humidity conditions of the outside air, but it is 5 to 20 with respect to 100 parts of the total dry weight of the chopped wood pieces (weight when the wood pieces are dried and reach a constant weight). About a part. When the amount of starch paste sprayed is 5 parts by weight or less, the adhesive strength decreases. On the other hand, in the case of 20 parts by weight or more, the moisture content after application of the adhesive becomes too high, leading to an extension of the hot pressing time, and the moisture in the wood pieces becomes water vapor at the time of opening pressure. It causes a so-called puncture that jumps out suddenly.

  In addition, according to the experiment by the present inventor, the starch obtained mainly from corn starch or wheat flour and added with a very small amount of an alkaline component (NaOH) and borax and stirred, has high adhesive strength despite its low viscosity. Was revealed. The compounding ratio at that time was starch: sodium hydroxide: borax: water = 29.7: 0.4: 0.3: 69.6.

  About the stirrer used when spraying a natural binder mainly composed of starch paste to stir the chopped wood pieces and stirring them, a large rotation provided with a stirring blade on the inner side used when manufacturing general particle boards The drum is used well. Although the time required for stirring depends on the number of revolutions, starch paste adheres almost evenly to the peripheral surface of the wood piece by stirring for about 2 to 7 minutes, and a film of natural binder is formed. When the stirring time is 2 minutes or less, the adhesive does not spread sufficiently, and if it is too long, the pieces of wood are further crushed by the stirring blades in the drum, and the water contained in the binder evaporates. Cause poor adhesion.

[Third step] After completion of the second step, an aggregate of chopped wood pieces with starch paste attached to the outer peripheral surface is laminated and hot-pressed at a temperature of 150 to 200 ° C for 10 to 20 minutes. A deck board having a predetermined size is produced by hot pressing.

  The reason why the pressing temperature is set to 150 ° C. to 200 ° C. is that when the temperature is lower than 150 ° C., it takes time to evaporate the water in the chopped wood pieces, which causes a problem in terms of production efficiency. Moreover, it is generally said that the properties of wood are chemically changed at 200 ° C or higher. When the pressing temperature is 200 ° C or higher, the surface layer of the chopped wood piece is hardened first, and the inside is hardened. It becomes difficult and the surface is burnt.

  The reason why the pressing time by hot pressing is set to 10 to 20 minutes is that if it is less than 10 minutes, the binder is not sufficiently cured, and if it is more than 20 minutes, the production efficiency is poor and it is economically disadvantageous. is there. The hot press used for hot pressing is called a flat plate press, and a laminated body of chopped wood pieces is inserted between two predetermined heated surface plates, and hydraulic pressure, water pressure, etc. It is heated and pressed by a movable surface plate that operates at A deck board having a predetermined size can be obtained by the hot pressing.

[Fourth Step] A recycled pallet is obtained by using the deck board obtained in the third step as the top plate 1 and the bottom plate 2, but the above-mentioned recycled material can also be used for the stringer 3. Not too long. In addition, when the recycle material is not used for the stringer 3, a heat-treated beam material is used to prevent the transfer of pests contained in the packing material. In order to fix the top plate 1 and the bottom plate 2 to the stringer 3 for maintaining the interval, nails or wood screws are used as in the conventional case.

[Results of deck board strength test, etc.]

<Test conditions> Conforms to the bending test method of JIS A5908 “Particle board” Specimen: width 50 mm, length 275 mm, thickness 15 mm, span 225 mm
Average deformation speed: 10 mm / min.
Room temperature: 20 ° C 60% RH

<Test results>
Bending strength when 10% starch paste is added to the absolute dry weight of the chopped wood piece 106.42Kgf / cm ²

<Resistance to mold>
The humidity inside the container during marine transportation rises to about 90%, so the specimen was left in an environment of 20 ° C and 95% RH for 4 weeks, and the occurrence of mold was visually inspected. It was.

The bending strength applied to the upper and lower deck boards is 31.6Kgf / cm ² with a load capacity of 500Kg and the deck board as a simple beam supported at both ends. However, the above test results satisfy it.

It is a perspective view which shows one Embodiment of the recycling pallet for cargo handling of this invention.

Explanation of symbols

1: Top plate 2: Bottom plate 3: Vertical girder

Claims (2)

A used wooden cargo handling pallet is chopped by a crusher, and the chopped wood pieces are heat-pressed with a natural binder mainly composed of starch paste to form a deck board of a predetermined size. A recycling pallet for cargo handling, characterized in that the deck board is used as a top plate and a bottom plate, and is fixedly disposed on both upper and lower surfaces of a stringer for maintaining a gap. A first step of chopping the components of the used wooden cargo handling pallet with a crusher, and a natural binder mainly composed of starch paste is sprayed on the chopped wood pieces obtained by the first step. The second step of mixing both with a stirrer to form a film of natural binder on the peripheral surface of the chopped wood piece, and after completion of this second step, the aggregate of the chopped piece of wood is laminated and hot pressed And a third step of producing a deck board of a predetermined size by hot-pressing for 10 to 20 minutes under a temperature condition of 150 to 200 ° C., and a deck board obtained by the third step with the top board and A method for producing a recycling pallet for cargo handling, comprising a fourth step of using as a bottom plate to obtain a recycled pallet.

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