JPS6172540A - Pallet of synthetic resin foamed and molded body and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain the titled pallet that has enough strength, and is lightweight and excellent in cushioning force, by joining the longitudinal ends of a plurality of pallet members each comprising a foamed and molded body that is produced in a mold from synthetic resin prefoamed particles. CONSTITUTION:Synthetic resin prefoamed particles are foamed and molded in a mold into pallet members 1, 1', which should have a density of 0.045-0.3g/cm<3>, preferably 0.05-0.18g/cm<3>, and a compression strength of 2.0kg/cm<2> or over when compressed 20%. The longitudinal ends of the pallet members 1, 1' are joined to integrate the pallet members 1, 1' thereby producing joined sections 3 and fork finger insertion sections 2 into which fork fingers of a fork lift will be inserted.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a pallet made of a synthetic resin foam molding used as a platform when transporting cargo by a forklift or the like, and a method for manufacturing the pallet.

(Conventional technology) Traditionally, pallets have often been made of wood or metal, but in recent years pallets made of synthetic resin injection molded products and pallets made of synthetic resin extruded foam have also come into use. Ta.

Also, Japanese Utility Model Publication No. 58-143322, Japanese Unexamined Patent Publication No. 58-143322
171342 and JP-A-58-171343 disclose a pallet made of in-mold foam molded polyolefin resin foam particles obtained by fitting an upper pallet component and a lower pallet component. is disclosed.

(Problem to be solved by the invention) The pallet is required to have sufficient strength. From this,
Wooden pallets and metal pallets use thick frame materials and thick board materials, and the pallets themselves are quite heavy.For this reason, wooden pallets and metal pallets have poor workability (,
It also had the drawback of lacking safety. In addition, wooden pallets were prone to hangnails and cracks, causing damage to cargo and injury to workers. Furthermore, since wooden pallets have water absorbing properties, bacteria such as mold and bacteria can easily grow on them.
This has been a particular problem in the food and pharmaceutical industries.

Pallets made of synthetic resin injection molding are often non-foamed and have poor hardness and cushioning power, so they have the drawback of damaging the cargo with the slightest shock.Pallets made of synthetic resin extruded foam are unique to extruded products. There is a directional "stress" that causes the pallet to warp.

Also, Japanese Utility Model Application Publication No. 58-14.3322, Japanese Unexamined Patent Application Publication No. 1983
The pallets disclosed in JP-A-171342 and JP-A-58-171343 require that each pallet component be molded to the same area as the pallet, and the area of the pallet component is large, requiring a large in-mold molding machine. Without it, production is impossible and uneconomical.

An object of the present invention is to provide a pallet that overcomes the drawbacks of the conventional products described above. In other words, the present invention provides a synthetic resin foam molded product that has sufficient strength, is lightweight, has excellent cushioning power, does not absorb water, does not warp, is easy to work with, and has excellent safety. The purpose is to provide manufactured pallets.

Another object of the present invention is to provide a method for manufacturing a pallet of synthetic resin foam molding, which can be sufficiently manufactured using a small-sized in-mold molding machine.

(Means for Solving the Problems) As a result of intensive research in view of the above points, the present inventors have found that the ends of a plurality of pallet component members made of in-mold foam molded articles of synthetic resin pre-expanded particles are connected to each other. The present invention has been completed by successfully developing a pallet made of a synthetic resin foam molded body in which pallet constituent members are joined in the width direction to integrate each other, and a method for manufacturing the same.

That is, the pallet made of a synthetic resin foam molded product of the present invention is obtained by joining two or more pallet component members each made of an in-mold foam molded product of pre-expanded synthetic resin particles at the ends of the component members in the width direction of the pallet. It has an integrated configuration. In addition, the method for manufacturing a pallet made of a synthetic resin foam molded product of the present invention includes filling a mold with pre-expanded synthetic resin particles, heating and foaming them, and molding pallet constituent members in the shape of dividing the pallet into two or more parts. Next, the ends of two or more pallet structural members are joined together in the width direction of the pallet, and the pallet structural members are integrated with each other to obtain a pallet having a desired shape and size.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

2, 4, 6, and 8 are perspective views showing one embodiment of the pallet of the present invention. In each case, 1.1' is a pallet component, 2 is a fork finger insertion part for inserting the fork fingers of a forklift, and 3 is a joint part, and the fork finger insertion part 2 is located opposite from one side of the pallet. It is formed so as to be connected to the other side facing the other side. The pallet component kl' is formed from an in-mold foam molded product of pre-expanded synthetic resin particles, and the foam molded product has a density of 0.045 to 0.3 g/cj, particularly a density of 0.05 to 0.18 g/cj. A material with a compressive strength of 2.0 kg/c+7 or more at 25% compression is preferable because it has sufficient strength, is lightweight, and has excellent cushioning power, and a density of less than 0.045 g/c+j. However, if the density exceeds 0.3 g/cd, the weight becomes too heavy and the workability decreases. Another 25%
Those whose compressive strength during compression is less than 2.0 kg/- also tend to have insufficient strength.

FIG. 1 is a perspective view showing the constituent members l of the pallet shown in FIG. 2;
3 is a perspective view showing the component 1 at the end of the pallet in FIG. 4, FIG. 5 is a perspective view showing the component 1 at the end of the pallet in FIG. 6, and FIG. FIG. 3 is a perspective view showing the component l of the end of the pallet. FIGS. 9 and 10 are partial sectional views showing the joints of the pallets shown in FIGS. 2 and 4, respectively. The pallet of the present invention uses pallet component members I and 1' divided into two or more parts, and their ends are joined in the width direction of the pallet. Joining in the "width direction of the pallet" means joining in the direction along the formation direction of the fork finger insertion part 2 as shown in Figures 2 and 4, as well as the case where the fork finger insertion part 2 is joined as shown in Figure 6. This also includes cases where the parts are joined in a direction perpendicular to the direction in which the portion 2 is formed. Also,
As shown in Fig. 8, "joining" includes the case where the ends of the components of the pallet are joined by heat-fusion or When bonding with adhesive (for example, No. 9
(As shown in the figure, the mutual joint surfaces of the pallet components are flat), In the case where the mating surfaces of the pallet components are flat, as shown in Figure 1O, the fitting is done by interlocking the concave part and the convex part, or (not shown in the figure), the concave part and the convex part are wedge-shaped. (It may also be the case that the fitting is done by the engagement of the concave part and the convex part as shown in Fig. 10, or the engagement of the wedge-shaped concave part and the convex part.) Not only are they mated together, but
(It may be heat-sealed or bonded with an adhesive.)

The pallet of the present invention may be a three-way pallet having two fork finger insertion portions 2 as shown in FIGS. 2, 4, and 6, or a pair of two fork finger insertion portions 2 as shown in FIG. The pallet of the present invention may be a four-way pallet having four insertion portions 2 intersecting each other at right angles.Also, the pallet of the present invention has three or more fork fingers. The above insertion portions may be provided.

The pallet of the present invention may be a double-sided pallet, as shown in FIGS. 2, 6, and 8, or a single-sided pallet, as shown in FIG. 4.

In addition to the above, the pallet of the present invention may have various shapes depending on the intended use.For example, protrusions may be provided at the corners of the pallet surface to prevent cargo from slipping off the pallet. It is also possible to form irregularities with a degree of slippage.

The pallet components in the present invention include polyethylene (low-density polyethylene, linear low-density polyethylene, high-density polyethylene, etc.), polypropylene, ethylene-propylene random copolymer, ethylene-propylene block copolymer, ethylene-styrene copolymer. , pre-expanded particles of olefin resins such as ethylene-vinyl acetate copolymers, styrene resins such as polystyrene, styrene-butadiene copolymers, styrene-maleic anhydride copolymers, and synthetic resins such as vinyl chloride resins. The pre-expanded synthetic resin particles may be cross-linked.
Among these, in-mold foam molding of pre-expanded particles of -°-fin type resin, which may be non-crosslinked, has sufficient toughness and flexibility, and is superior in impact resistance. It is most preferable because it has a high buffering force.

Furthermore, if a weather-resistant material such as carbon black, an antioxidant, an ultraviolet absorber, etc. are mixed into the in-mold foam molded product of pre-expanded synthetic resin particles forming the pallet of the present invention, the pallet with excellent weather resistance can be obtained. It's preferable.

The pallet of the present invention may use reinforcing tools to increase the strength of the pallet. For example, FIG.
There is a sectional view taken along the line XI, and Figure 12 is taken from X1l-X in Figure 2.
As shown in the cross-sectional view, a reinforcing device 5 and a fastening portion 6 are used in each case. A screw groove for fastening is formed in the reinforcing tool 5, and the fastening tool 6 is screwed into the reinforcing tool 5 to fasten the reinforcing tool 5. In the pallet component, insertion holes 4 for reinforcing tools 5 may be formed in advance, for example, as in the component 1 shown in FIGS. 1 and 3, or as in the pallet shown in FIGS. 6 and 14. The rliffi hole for insertion into the reinforcement 5 may be formed later, not only when inserting in the direction crossing the joint 3 as shown in FIGS. 2, 4, and 6, but also in the direction shown in FIG. It may be inserted along the joint part 3 at the joint part 3 as shown in FIG. It may be inserted along the joint 3, or the joint 3 may be inserted along the joint 3 as in the embodiment of FIG.
The reinforcing device 5 may be inserted in the direction crossing the joint 3 and parallel to the joint 3 near the joint 3, or the reinforcing device 5 may be inserted only in the direction crossing the joint 3, only at the position of the joint 3, The reinforcing device 5 may be inserted near the joint 3 only in a direction parallel to the joint 3. In particular, it is preferable to insert the reinforcing device 5 in a direction crossing the joint 3 because the reinforcing effect on the pallet becomes large. The number of reinforcing tools 5 is seven in FIG.
Although the number is 11 in FIG. 14, it may be selected as appropriate.

The reinforcing tool 5 may have a shape of a pipe or a rod.
metals such as iron and aluminum, and reinforced plastics (F).
RP) or the like is used as appropriate.

FIG. 15 is a perspective view showing still another embodiment of the pallet of the present invention. In this pallet, the opening edge side of the fork finger insertion portion 2 is covered with a protective cover 7. As shown in FIG. 16, the protective cover 7 covers the edge portions 8 on both the left and right sides of the pallet to prevent the pallet from being damaged, and at the same time protects the opening 2' of the fork finger insertion portion 2 and the opening 2' of the fork finger insertion portion 2. The protective cover 7 also covers a part of the fork finger insertion part 2 near the part 2' to prevent the pallet from being damaged by the fork fingers during operation, and also has the effect of increasing the strength of the entire pallet.

The protective cover is not limited to the shape shown in FIG.
The four circumferences of the pallet may be covered, or the four circumferences of the pallet may be covered by fitting a protective cover of the shape shown in Fig. 15 around the four circumferences of the pallet. (Use a protective cover without an insertion hole on the side wall without section 2'.)

It is preferable that the inner wall 9 of the fork finger insertion part 2 is protected by a protective material 10 as shown in FIG. A long hollow shape with a rectangular cross section that can cover almost the entire surface of the inner wall 9 is particularly preferable, but it may partially cover the upper, lower, left, and right inner walls 9. Part 2 The ceiling of the inner wall, etc. may come in contact with the fork fingers during transportation and be particularly damaged.
A protective material may be provided partially at a key point where it is easy to do so. In this case, the protective material may be, for example, a strip, a pipe, or a rod. In the case of a pipe or a rod, the protective material may be provided on the ceiling of the fork finger insertion part 2. It is preferable that two pipes are provided as a pair in each section, and the distance between these two pipes or bars is slightly narrower than the width of the fork fingers.

FIG. 17 is an enlarged explanatory view of the engagement portion between the protective cover 7 and the protective material 10 in FIG. 16.

By locking and connecting the protective cover 7 and the protective material IO in this way, both the protective cover 7 and the protective material IO can be reliably attached to the pallet, which is preferable.

FIG. 18 is a perspective view of main parts showing still another embodiment of the pallet of the present invention. As shown in FIG. 20, this pallet has an edge protection cover 118 that covers the edge 8 of the pallet.
The opening 2' of the fork finger insertion portion 2 and its surroundings are covered with the insertion port protection cover llb. In this case, the insertion port protective cover 11b and the protective material 10. ! - is the 17th
It is preferable that they be connected by the same interlocking structure as shown in the figure.

Further, as shown in FIG. 19, a reinforcing material lO' having a hollow shape with a rectangular cross section is used to strengthen the inner wall 9 of the fork finger insertion part 2 around the part corresponding to the joint part 3 and/or the tip of the fork finger. You may cover only.

The above-mentioned reinforcing material 10, IO' may be made of metal such as iron or aluminum, reinforced plastic (FRP), or the like, as appropriate.

The protective cover 7, edge protective cover 11a, and socket protective cover 11b are made of acrylonitrile-butadiene.
Injection molded products made from styrene copolymers, styrene-butadiene copolymers, high-density polyethylene, polypropylene, ethylene-vinyl acetate copolymers, etc., molded products made from thin plates of metals such as iron and aluminum, etc. are used as appropriate. be done.

The method for producing a pallet of the present invention involves first filling a mold that can be closed but not sealed with pre-expanded particles, heating and foaming the pallet to divide the pallet into two or more parts (in-mold foam molding). body).

The pre-expanded particles used at this time have a density of 0.03 to 0.45 g.
The density of the pre-expanded particles, which is preferably /-, is the bulk density, which is the value obtained by dividing the weight of the pre-expanded particles when a container of about 200 cc is filled with the particles by the volume of the container. If you want to obtain a weather-resistant pallet, pre-expanded particles should be coated with a weather-resistant material such as carbon black or oxidation preventive material.
Alternatively, a weather-resistant material, an antioxidant, an ultraviolet absorber, etc. may be mixed into a mold that can be closed, but cannot be sealed, together with pre-expanded particles, and heated.
The above-mentioned mold, which may be foamed, has an inner surface shape corresponding to the shape of the final pallet divided into two or more parts, and a heating medium such as steam passes through the mold surface. A material with small holes can be used.

Next, the ends of the pallet component members divided into two or more are joined together in the width direction of the pallet.
Then, the pallet components are integrated. Prior to joining, it is preferable to make the dimensions of each pallet component uniform by cutting or the like. As described above, joining methods include, for example, heat fusing using an appropriate heating means, bonding with an adhesive, Examples include means for engaging and fitting concave portions and convex portions formed at each end of the pallet constituent members to be joined.

When heat fusing is performed, by forming the pallet constituent members in advance to be slightly larger than a predetermined size, the dimensions can be accurately adjusted depending on the degree of fusing during fusing. Examples of the heating means used during heat fusion include a heating plate, heating blade, hot air, and the like.

When bonding with adhesive, the dimensions are reduced to U4 by cutting the ends of the pallet components to be joined to an arbitrary width, or conversely, by inserting an intervening member of an arbitrary width between both ends. Examples of the adhesive include acrylic resin, vinyl acetate resin, olefin resin, ethylene-vinyl acetate copolymer, acrylonitrile-butadiene rubber copolymer, polyvinyl alcohol, An adhesive containing a styrene-butadiene rubber copolymer or the like is used.

At the time of joining, pallets having various widths and heights can be manufactured by suitably combining and joining pallet constituent members.

After the ends of the plurality of pallet constituent members are joined together in the width direction of the pallet as described above, the reinforcing tool 5, the protective cover 7, the protective material 10, 10' edge protective cover Za,
A pallet made of synthetic resin foam molding can be obtained by appropriately attaching the insertion hole protective cover 11b and the like.

(Effects of the Invention) The pallet made of the synthetic resin foam molding of the present invention has sufficient strength, is lightweight, and has excellent cushioning force. Furthermore, since the pallet of the present invention is made of an in-mold foamed product made of pre-expanded synthetic resin particles, there is no "stress" in a specific direction, there is no risk of warping, there is no deformation due to distortion, and there is no difference between the pallet and the wooden pallet. There is no risk of hangnails or cracks, so workability is good and safety is excellent. Furthermore, since the water absorption is extremely low, there is no possibility of the spread of germs such as mold and bacteria.

Further, according to the method for manufacturing a pallet made of a synthetic resin foam molded product of the present invention, pallets of various sizes can be produced by appropriately combining pallet constituent members in the shape of a pallet divided into two or more parts and joining them in the width direction of the balent. Even if pallets of different sizes are manufactured, there is no need to prepare molds corresponding to the sizes of each pallet, and the molds for forming the pallet components used in the present invention are small. Since it can be used as a material, the cost of molding molds can be significantly reduced, and pallets of various sizes with excellent physical properties can be manufactured at low cost.

[Brief explanation of the drawing]

The first leap, FIG. 3, FIG. 5, and FIG. 7 are perspective views, FIG. 2, FIG. 4, FIG. 6, and FIG. 13, 14, and 15 are perspective views showing different embodiments of the bullet of the present invention, FIG. 9 is a vertical sectional view of the main part along IX-IX vA in FIG. 11 is a longitudinal sectional view of the main part along the line X-X&l in FIG. 4, FIG. 11 is a sectional view taken along the line XI-XI in FIG. 4, and FIG. XVr-XVI iJl plane sectional view in Figure 15,
FIG. 17 is an enlarged schematic view of part A in FIG. 16, FIG. 18 is a perspective view of the main parts of another embodiment of the pallet of the present invention, and FIG. 19 is
Plane sectional view of still another embodiment of the barre 7) of the present invention, No. 20
The figure is a longitudinal sectional view of the main part along XX-XX Mll in FIG. 18. l, 1'...Pallet component 3...Joint part Patent applicant Japan Styrene Paper Co., Ltd.Figure 1Figure 2Figure 9Figure 10Figure 13rlliFigure 14Figure 15Figure 16 Figure 17 Figure 18

Claims (4)

[Claims] (1) A composition characterized in that two or more pallet constituent members made of in-mold foam molded articles of pre-expanded synthetic resin particles are integrated by joining the ends of the constituent members in the width direction of the pallet. Pallet made of resin foam molding. (2) Density of pallet components is 0.045-0.3g
/cm^2, compressive strength at 25% compression is 2.0kg/c
A pallet made of a synthetic resin foam molding according to claim 1, which has a diameter of m^2 or more. (3) Fill a mold with pre-expanded synthetic resin particles, heat and foam them to form pallet components in the shape of dividing the pallet into two or more parts, and then connect the ends of the two or more pallet components to each other. A method for manufacturing a pallet made of a synthetic resin foam molding, which comprises joining in the width direction and integrating pallet constituent members to obtain a pallet having a desired shape and size. (4) The density of the synthetic resin pre-expanded particles is 0.03 to 0.4
A method for producing a pallet made of a synthetic resin foam molding according to claim 3, wherein the pallet has a weight of 5 g/cm^2.