JPH0110357Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention is a cushioning and fixed packaging made of a thermoplastic resin foam molding that can be used in combination with a cardboard case or alone as a packaging material for various products including home appliances. In particular, when the molded body is brought into contact with the corner of the packaged object, the impact load exerted on the molded body by the packaged object at the corner ridgeline, and the direction of the impact load exerted on the formed body by the contact surface. The present invention relates to a molded body having a structure to suppress cracking in the case where cracking occurs due to impact loads such as dropping due to a gap between the parts.

(Prior art) Cushioning packaging protects against shocks and shocks that occur during transportation and cargo handling.
The purpose is to protect the function and condition of the product from external forces such as vibrations, and it is usually designed with two functions: a buffer function when receiving impact loads due to drops, etc., and a fixation function during the product transport process. Necessary packaging functions are provided according to the requirements.

In this cushioning packaging, thermoplastic resin foam moldings such as styrofoam packaging materials are most often used as the inner cushioning packaging material, and there are two types depending on the usage: full-cover type and partial-cover type. When exposed to various shocks during cargo handling or transportation, although it exhibits a buffering function, external forces exceeding a certain level can cause the packaging material to crack, which in turn can cause the packaging material to break and peel. There are many cases. This phenomenon of cracking of the packaging material tends to occur particularly when the packaging material falls at a corner or edge as shown in FIGS. 1 and 2, and there is a risk of short-circuiting resulting in breakage due to the bottoming out phenomenon of the product.

However, regardless of whether the packaging material is damaged by cracking or not, it must not impair its ability to secure the product even after being subjected to an impact load.

According to the inventors' research, the cushioning properties of foamed polystyrene, which is a typical packaging material using thermoplastic resin foam moldings, change depending on the expansion ratio, but basically the The behavior of the buffering properties represented by the stress-strain properties shown in Fig. 11 is shown.

Normally, when designing impact packaging to keep the acceleration generated on the packaged cargo due to a fall impact within a certain allowable acceleration, there is an optimal size and amount of impact packaging material that takes economic efficiency and cushioning characteristics into consideration, and the factors that determine this are the product weight W ₁ (Kg), allowable acceleration G ₁ of the product, and equivalent fall height h (cm).In order to achieve the most efficient buffer design, the buffer coefficient C and dynamic stress σ _nax shown in Figure 11 are The calculation method using is the most commonly used.

Packaging material thickness t (cm) = C・h/G ₁ Pressure-receiving area S (cm ² )=G ₁・W ₁ /σ _nax The buffer coefficient C and dynamic stress σ _nax, which are the basis of the above buffer design, are the 11th When calculating from diagrams, it is necessary to consider economic efficiency (manpower, material cost) and shock absorber characteristics, and it is most desirable to adopt a value that places the strain of the styrofoam in the range of ≒50 to 65%. .

In other words, cushioning packaging using Styrofoam has a large compression deformation (strain≒50-60%) of Styrofoam.
This means that it is a packaging (buffering) method based on the basic premise of using polystyrene resin, and at the same time, it must be taken into account that polystyrene resin is originally a thermoplastic and hard resin, has poor flexibility, and is extremely brittle. For example, cracking of polystyrene foam used as a cushioning material is a fateful matter, and suppressing cracking is an unavoidable problem.

By the way, Styrofoam has a property that no cracking phenomenon occurs even if a strain of 80% or more is applied to the flat plate only in the direction of simple compression. However, as mentioned above, it is brittle on the one hand, so while it is strong against loads in the compression direction, it is weak against other forces such as shearing, bending, and tension. As a result, as shown in Fig. 13, for example, when falling from a corner edge, the left and right packaging materials forming the corner open left and right before the packaging material collapses due to compression, causing the above-mentioned cracking phenomenon due to the so-called opening moment. This results in loss of buffering effect.

Moreover, as a practical matter, the directions of impacts that occur during actual cargo handling, transportation, etc. are irregular and complex.

This can be easily inferred by looking at cracking phenomena during the actual distribution process, or from the fact that most packaged cargo drop test standards specify and evaluate drops from one corner, three edges, and six sides.

Therefore, when analyzing the mechanism of cracking of cushioning packaging materials and developing techniques for suppressing cracking, it is necessary to consider face-to-face, diagonal, diagonal edges, and combinations thereof.

By the way, when we used a model to analyze the mechanism of cracking of packaging materials due to drop impact, we found that the first problem in the model's image of a fall is
It was found that this was a corner edge fall as shown in Fig. 2.

Therefore, it has been found that it is more effective to develop techniques for suppressing cracking of packaging materials by focusing on corner edge falls.

Therefore, the purpose of conventional drop tests is to prevent damage caused by cracks in packaging materials that may damage the product fixing function when subjected to impact loads predicted during the transportation process. Therefore, various measures have been taken, such as lowering the expansion ratio of thermoplastic resin foam moldings and increasing the wall thickness.

On the other hand, various attempts have been made to improve the shape of the packaging material as described above to increase its buffering capacity against impact loads. , and providing a groove in the center of this notch surface to increase the impact effect (Utility Model Application No. 51-89071) has been proposed.

(The problem that the invention aims to solve) However, the former method naturally leads to an increase in the amount of foam molded material used, an increase in the number of packaging materials, and a reduction in the original cushioning properties. On the other hand, although the latter method has some effect on the cushioning properties of lightweight packaging products, due to the phenomenon of wall thickness at the ridgeline where the impact load of the product acts,
In packaging that weighs more than No consideration is given to deviations in direction from the load.

In other words, due to the location of the center of gravity of a product package and the thickness of the packaging material, when a product package is dropped from a ridgeline, it is extremely rare for the impact load that the packaging material receives from the packaged object and the impact load that it receives from the ground surface to be on the same line. If they are on the same line, both the upper and lower loads collide and a compressive deformation load acts on the packaging material, but in reality, depending on the center of gravity position and the thickness of the packaging material, the first As shown in the figure, there are many cases where displacement occurs, and in this case, in addition to the compressive deformation load, other forces such as shear force, bending, and tension due to the displacement of both loads act, causing more or less cracking. However, no consideration has been given to such issues.

The present invention addresses the above-mentioned conventional problems, and focuses particularly on falls on ridgelines where the greatest damage due to cracking of packaging materials occurs, and provides an effective method for dealing with deviations in the direction of the impact load. It is an object of the present invention to provide an effective packaging material configuration.

(Means for Solving the Problems) That is, the features of the present invention that meet the above objectives are that the foam is made of thermoplastic resin foam and has three faces of the required thickness that are orthogonal to each other, and the outer shape is a box. Used in contact with the corner of a package, and at the ridgeline of the corner, for cushioning and fixing when there is a deviation between the impact load that the packaged item exerts on the packaging material and the direction of the impact load that is applied to the packaging material on the contact surface. It is a packaging material,
On the outer surface side of the corner ridge line opposite to the surface in contact with the packaged object, a meat strip is provided that extends over the two surfaces forming the ridge line, and the meat strip is spread out from the ridge line on the two surfaces. The difference is that when falling from a ridgeline, the outer surface of the package has a larger extension length out of the respective angles θ ₁ and θ ₂ formed between the outer surface and the ground surface.

In addition, when providing the meat stealing in the above-mentioned configuration of the present invention, it is not limited to the entire length range of the ridgeline on the outer surface side, but may be a part of the length range, since the corner part is particularly problematic when the ridgeline falls. This is a partial corner patch method in which the packaging material is used in contact with only the corner portion of the packaged object, and in some cases, the meat stripping may be provided over the entire length of the outer ridgeline from which it falls. Although this is preferred, it is not always necessary when the packaging material extends not only to the corner portions of the packaged object but also to the entire ridgeline of the packaged object including the corner portions (see Figures 7 and 8). Rather than using the entire length range, only the corner portion and a part of the length range adjacent thereto are sufficient to achieve the function.

(Function) The packaging material of the present invention, which has the above-mentioned configuration, is capable of resisting shearing, bending, and pulling other than compressive deformation loads when falling from the ridgeline when used in contact with the corner ridge of the product package (when used in contact with the insertion section). The tension and other forces are suppressed as much as possible,
Suppresses the occurrence of cracks.

This will be explained in detail below.

As shown in FIG. 10A, an object to be packaged (product) applies acceleration to the packaging material when it falls, and an impact load W is applied in the direction shown in the figure.

On the other hand, on the ground contact side, the impact load W
Load P acts as a reaction to absorb the force.

By the way, when falling on a ridge, the angles θ ₁ and θ ₂ that the outer surface of the package makes with the ground plane have different magnitudes, and since θ ₁ < θ ₂ , the packaging material is also tilted left and right with respect to the direction of the load from the packaged object. The lengths l ₁ and l ₂ of are non-uniform, and in the figure l ₁
>l ₂ (usually 8:5).

In other words, there is a deviation in the direction of both loads.

Therefore, as shown in Figure 10A, if we look at the case where there is no meat stealing in the packaging material, even if there is a deviation in both load directions, there is not much influence at first, and the above-mentioned upper and lower loads W and P are Therefore, the packaging material generates compressive strain based on simple compression and has a buffering effect, but when a smaller external force is applied, the load is received directly below the load W from the package due to the deviation between the two loads mentioned above. Therefore, due to the non-uniformity of the lengths l ₁ and l ₂ in the direction of the load from the object to be packaged, the surface that receives the load from the object to be packaged becomes uneven on the left and right sides, and the inner and outer ridge lines at the corners are When the connecting midpoint O is reached, a movement similar to cutting by the double blades of scissors occurs around the midpoint O, and this becomes a shearing force other than the compressive deformation load, causing a crack, and the The buffering capacity is lost, and the packaged product hits the floor and gets damaged.

On the other hand, as shown in Fig. 10B, for example, if we take 20% of the distance H between the inner and outer ridge lines of the corner part so that the position of the outer surface ridge line Q approaches the position directly below in the direction of the load W from the packaged object. In this case, the said 20%
Up to this point, the compressive strain of the packaging material ensures simple compression based on the coincidence of both the upper and lower load directions, suppressing cracking, and exerting an effective buffering force in that range. However, if it exceeds 20%, the receiving surface that bears the load W from the packaged object becomes uneven from side to side, as in the case without meat theft, and cracks occur in the same manner as described above.

Therefore, the meat steal is further increased, and the grounding ridge line becomes the first
As shown in Figure 0 C, if it is placed directly under the load W from the packaged object, if this is 60%, the distance H between the inner and outer edges up to 60% will be the same as the above 20%. It exhibits buffering capacity through simple compression and does not cause cracks.

However, of course, if the impact energy exceeds 60% and the impact energy still remains, there is a possibility that cracks will occur as described above.

By the way, as mentioned above, in cushion packaging, the standard distortion amount of the packaging material is around 60% for foamed polystyrene, and it is usually said that compression work of about 60% of the distance between the inner and outer edges is sufficient.

Therefore, it is practically sufficient for meat stealing if the larger spread is about 60% of the distance H.

However, compared to the case where there is no meat stealing at all, the meat stealing expands the buffering capacity portion by simple compression, as described above, and has the effect of suppressing cracking.

This is also clear from Figures 13 and 14, and when the ridge line A shown in Figure 9 touches the ground in the case of falling from a ridge line as shown in Figures 1 and 2, , if there is no flesh loss on the two surfaces A and B that form this ridgeline, as shown in Figure 13, the packaging material's grounding part will be compressed and deformed due to the compression function of the packaging material itself, and the load received from the grounding surface will be Even if it is distributed over two surfaces and exerts a buffering function (see Fig. 13), there still remains a difference between the load W received from the packaged object and the load P received from the ground surface, which is based on the predetermined compression. After distortion occurs, if there is an external force greater than that, both the above loads P and W are applied.
Due to forces other than compressive deformation loads such as shear force, bending, and tension caused by the misalignment, cracks occur as shown in FIG. 13C.

However, in the packaging material of the present invention, the ridge line (9
As shown in Figure 2, when the material in Figure A) is subjected to an impact load from the ground surface, the packaging material itself has a compression function (normally the outside of the packaging material is covered with a cardboard case, but this case is not considered). Even if the packaging material is compressed and deformed by
The direction of is the second direction from the direction of the arrow P line in FIG.
Shifts to the direction of the arrow P in the figure, and the deviation between the load received from the packaged object and the W direction decreases or almost disappears, and the force due to shear, bending, and tension other than the compressive deformation load, especially the shear The force decreases or almost disappears, and the load becomes only in the direction of simple compression, which is said to be strong against the packaging material, and there is almost no cracking phenomenon, and as shown in Figure 14, a considerable amount of strain is applied. The cracking phenomenon will no longer occur.

Thus, when the packaging material of the present invention is used and brought into contact with the corner of a box package, the difference between the impact load received by the packaging material from the ground surface and the impact load received from the packaged object becomes small, or It is possible to suppress damage caused by cracks that occur in packaging materials when they are completely removed.

(Example) Hereinafter, preferred examples of the packaging material of the present invention will be described in detail with reference to the accompanying drawings.

Figure 1 shows a product packed in a conventionally shaped packaging material, with the direction of the center of gravity of the package coinciding with the outer ridgeline of the packaging material, where the ridges of the packaging material are most susceptible to cracking damage. FIG. 2 shows an example in which the packaging material according to the present invention is used in a similar state.

In each of these figures, 1 shows the product body, 2 shows the packaging material using a thermoplastic resin foam molded body with side pads including corner parts, 3 shows the outer cardboard case, and C shows the center of gravity of the package. , and θ ₁ and θ ₂ are the angles that the external surface of the package makes with the ground plane 4 when falling from the ridgeline, P is the impact load that the ground plane 4 acts on the packaging material, and W respectively indicate the impact load that the packaged item exerts on the packaging material.

In the conventional method shown in FIG. 1 above, the state in which the packaging material receives an impact load due to falling from the edge is shown in an enlarged view in FIG. A difference occurs between the impact load W received from the packaged object and the impact load P received from the ground plane 4.

Therefore, in such a case, larger forces such as shearing and bending other than the compressive deformation load are generated inside the molded body, so that it is extremely susceptible to cracking damage, as described above.

On the other hand, the part indicated by the reference numeral 5 in FIG. 2 and FIGS. On the two outer surfaces A and B on the opposite side to the contacting surfaces, a flesh cutout 5 is provided along the ridge direction in part or all of the ridgeline portion (see FIGS. 8A and 9B). This meat stealer 5
The part marked with is the ridgeline on the outer surface of the packaging material (see Figure 9 A)
If the package is a box, it is more suitable to provide it in all areas, but if a part that is likely to receive impact load when dropped is identified, it may be sufficient and effective to provide it only in that part. be.

Although the shape of the meat stealer 5 is approximately rectangular in cross section in FIG. 2 and FIG.
The cross-section may have a scalene triangular shape as shown in FIGS. 6 and 6, or may have other equivalent shapes. However, the most common shapes include the rectangular shape or scalene triangular shape.

Further, the size of the meat stealing 5 is not particularly limited, but in the present invention, the larger angle θ ₂ of the angles θ ₁ and θ ₂ formed between the outer surface of the packaging material and the ground surface is used. The packaging material is provided with a thickness b approximately equal to the amount of compressive deformation caused by the impact load on a part or all of the edge with respect to the direction of the surface B having the above-mentioned Is it possible to extremely minimize the deviation between the load P from the ground surface that the packaging material receives and the load W from the packaged object by arranging the meat loss dimension smaller than dimension b and applying irregularly shaped meat loss along the ridge line? , or eliminate it completely.

Each example in FIG. 4, FIG. 5, and FIG. 6 is as follows.
All of them are constructed with such consideration in mind.

7 and 8 are perspective views showing the form of the above-mentioned packaging material to make it easier to understand. In FIG. In the figure, on both sides of the lower part, a portion of the outer surface side ridgeline A is provided with a thinning 5 extending over the two surfaces A and B forming the ridgeline A and having different lengths a and b.

Figures 12, 13, and 14 are examples comparing the state of deformation due to load between the packaging material _S1 of the present invention, which is provided with meat stripping of different spreads, and the packaging material _S2 , which is not provided with the meat stripping. As shown in Fig. 12, the performance of comparative packaging material _S2 without meat stealing is 60~
70Kg/15cm, compressive displacement is about 10mm, whereas the packaging material S ₁ of the present invention has a compressive load of 100Kg to 15cm,
It has the ability to have a compressive displacement approaching 20 mm, and when actually used, whereas the comparative packaging material without flesh stealing shown in Figure 13 cracks at a compressive strain of 30% in Figure C. It was confirmed that the packaging material of the present invention shown in FIG. 14 did not suffer from any cracking damage even at a compressive strain of 30%.

Thus, it can be seen that the packaging material of the present invention is extremely effective against cracking damage and has excellent performance as a packaging material.

In addition, as mentioned above, the above-mentioned meat stealing in the present invention is particularly problematic at corner parts when falling from a ridgeline, and therefore, in the case of a partial corner patch method, it is preferable to provide the meat over the entire area. In the case where the ridge line portion extends over the entire length as shown in FIG. 8 or FIG. 8, it is not necessarily necessary to cover the entire length of the ridge line portion, but even a corner portion and a portion close to the corner portion can sufficiently perform the function.

(Effects of the invention) As described above, the present invention provides a packaging material in which a part or all of the length of the ridge on the side opposite to the surface where the packaging material contacts the packaged object, that is, the outer surface of the packaging material, is This is a method in which the ridge line is provided and the spread length of the meat thieves is made different on the two surfaces forming the ridge line, and by making the spread length of the meat thieves different, it is possible to reduce the impact from the ground surface that the packaging material receives and the product surface. By aligning the directions of the impact loads as much as possible, and virtually eliminating deviations in both load directions, we are able to eliminate the cause of cracks in the packaging material due to drop impact, even when the thermoplastic foam molded product is dropped from a ridge, where the most damage from cracking occurs. It has a remarkable effect in eliminating damage and achieving damage control.
Furthermore, unlike lowering the foaming ratio or increasing the wall thickness of the molded body, it is possible to save the same material, making it an extremely effective packaging material industrially and practically.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing a state in which a product packed using a conventionally shaped packaging material falls from the edge, Fig. 2 is an explanatory diagram showing a state similar to Fig. 1 described above using the packaging material of the present invention, and Fig. An enlarged view of the main parts in the figure, Figure 4 is the second
5 and 6 are enlarged views of important parts similar to FIG. 4 according to other embodiments of the present invention,
FIGS. 7 and 8 are external perspective views showing examples of packaging materials according to the present invention. In addition, FIG. 9 is a perspective partial view for explaining the packaging material of the present invention from a different perspective.
Figure 0 A, B, and C are action explanatory diagrams, where A shows the case where there is no meat stealing, B shows the case where some meat stealing is provided, and C shows the case where even more meat stealing is provided. Next, Fig. 11 is a diagram showing the behavior of the cushioning properties, Fig. 12 is a comparison diagram of the packaging material of the present invention and the comparative packaging material when falling at an angle of yaw angle, and Fig. 13 A, B, and C are the diagrams of the comparative packaging material. Figure 14 A, B, and C are explanatory diagrams showing the case of foaming with 0 compressive strain, B with 20% compressive strain, and 30% compressive strain in the displacement state under compressive load. In the displaced state, as in Figure 13, A is compressive strain 0.
%, B is an explanatory diagram showing the case where the compression strain is 20%, and C is the case where the compression strain is 30%. 1... Material to be packaged, 2... Packaging material, 3... Exterior cardboard case, 5... Meat stealing, A... Outer side ridge line, A, B... Two surfaces forming the ridge line.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. A thermoplastic resin foam molded product having three sides of the required wall thickness that are perpendicular to each other, and used in contact with the corner portion of a package having a box-like outer shape. A shock-absorbing and fixed packaging material used when there is a deviation between the direction of the impact load that the packaged object exerts on the packaging material at the corner ridgeline and the impact load that the ground contact surface exerts on the packaging material, and the packaging material The ridgeline on the outer surface side opposite to the surface in contact with the packaged object has a meat stripping extending over two surfaces forming the ridgeline, and the flesh stripping extends from the ridgeline on the two surfaces. They have different lengths, and are characterized in that the larger side of the angles θ ₁ and θ ₂ formed between the outer surface of the package and the ground surface when falling from a ridgeline has a larger spread length. Cushioning fixed packaging material. 2. The cushioning and fixing packaging material according to claim 1 of the utility model registration claim, in which the meat strip has a substantially rectangular cross section. 3. The shock-absorbing fixing packaging material according to claim 1 of the utility model registration claim, in which the meat strip has a substantially scalene triangular cross section.